Abbreviation for American Society for Testing and Materials. ASTM is a highly respected organisation, its specifications, standards and recommendations regarding material properties and their test methods are widely accepted worldwide by paint industry as well as many other industries.
Thermoplastic copolymer of acrylonitrile-butadiene-styrene that easily softens and deforms when heated.
Complete incorporation of another substance or energy into a matter. (e.g., Absorption of resin into the plastered surface, absorption of sun light by black object, s.o.)
Organic coatings that do not fill and close the small pores of the wood. Open-pore coatings, wet the small crevices without filling and closing them either because they are applied at the low film thicknesses or because they wet the crevices very well due to teir relatively low surface tensions which can be achieved with the help of additives.
Polyacid that is obtained by oxidation of cyclohexane and that improves the flexibility of the polyester resins while weakening the water resistance when used in the synthesis of polyester resins.
Melting point: 153°C
Adhesion of material as a thin molecular layer, to a solid or liquid surface, it is in contact with.
Equipment that burns the otherwise emitted solvent vapors produced during baking the oven-cured coatings rather than emitting the vapors to the environment. The heat formed in the afterburners is used by heat exchangers to pre-heat the air used for burning, reducing the energy consumption.
Lightly packed cluster of pigment particles formed by contacts of the corners of the particles with resultant air pockets between the particles. See Also Clusters of pigments and extenders
Strongly packed cluster of pigment particles that are formed through intense contact of particle surfaces. Breaking down to primary particles needs high amount of energy only accessible by grinding. See Also Clusters of pigments and extenders
General term for coatings with superior corrosion resistance and mechanical properties for protection of the surfaces prone to corrosion
Mixture of solvents obtained at 226-285°C interval during distillation of aromatically rich petroleum. Evaporation number relative to ether: >1000; specific gravity: 0,990; refractive index: 1,591; flash point: 102°C
Class of motor vehicles with a minimum loading capacity of 3,5 tons, including buses for minimum 8 persons (excluding the driver) and load trucks. Also called “heavy vehicle”. See Also Motor vehicles
Weight percent of non volatile substances present in an organic coating.
Weight average molecular weight is calculated by summing the products of the weights of each species and their molecular weights and dividing by the total weight of the mixture.
General term for organic coatings used for protection and decoration purposes on wood surfaces for indoor and outdoor applications such as furniture, doors, window frames, floors, fences etc. Some examples of wood coatings are: wood preservatives, stains, primers, sealers, putties, pigmented and clear topcoats.
A wood layer of around 0.5 mm thickness to cover the surfaces of solid wood, chipboard and MDF. Veneers are made of different trees using different cutting techniques. Veneers are bonded to wooden substrates using glues (adhesives).
Substrates that primarily comprise wood as the main component. In Turkey, solid wood, plywood, veneer, chipboard, MDF and hardboard are used as main wooden substrates.
Its wood is heavy, light colored and tough. It is easily processable with hand tools and machines. It is used in production of rotary-cut veneer or sliced veneer. Fiddleback-grained wood of maple is traditionally used for parquet making, musical instruments, backs of violins, pulley wheels, brush handles and production of food packaging cups.
Cylindrical cups, of generally 100 ml inner volume, with flat or conical bases and holes at the bottom, used to measure fluid viscosity. There are various flow cups defined by various standards (e.g. DIN cups, ISO cups, Ford cups, Afnor cups, Iwata cups)
General term for substances that demonstrate flowing behaviour. Liquids and gases are fluids.
Application of coating to the surface by pouring the coating by means of a hose etc. Coating is then collected in a bottom container to be pumped back to flow coating process.
Coating defect described by runny and non-levelled appearance after applying the coating to a vertical surface and giving enough time to the coating to form a solid film. The possibility of sagging increases with increasing coating thickness. The maximum possible film thickness that a coating can be applied to a vertical surface without observing sagging is called the “sagging limit”.
Acrylic monomer used in synthesis of acrylic resins with amide functional groups. Polyacrylamide polymers can be synthesized to carry a carboxylic acid functional group and can cross-link with epoxy resins. In addition, self cross-linking acrylamide resins can be synthesized by copolymerization of acrylamide and monomers carrying hydroxyl functional groups.
The most widely used acidic monomer in acrylic polymer synthesis.
Chemical name: Propenoic acid, vinyl formic acid
Melting point: 13°C; Boiling point: 142°C
Class of resins formed by addition polymerisation of acrylic and metacrylic acids and their esters over their ethylene double bonds with the help of free radicals. If acrylic acid esters and metacrylic acid esters have functional groups, the resulting is a thermoset acrylic resin, or else, the product is a thermoplastic acrylic resin. Solvent soluble, water-thinnable, water emulsion types are available.
Term especially used for spray applications. It defines the percentage of the amount of paint that reaches the surface, to the total amount of sprayed paint:
Type of polyethylene having a more branched structure compared to another widely used polyethylene (HDPE) resulting in more empty volume and thus lower density. LDPE has lower crystallinity and tensile strength than HDPE, however, it has higher formability and biodegradability.
General name for solvents having a linear structure and are able to dissolve low polarity binders such as long oil alkyd resins. These types of solvents are produced from distillation of high aliphatic content petroleum. Hexane, heptane and white spirit are a few of the aliphatic hydrocarbon solvents
Resistance of organic coating films against the destructive effect of chemicals with basic character. Basic chemicals causes structural breakdown of ester resins (e.g. alkyd and polyester resins) and some organic pigments.
Cleaning of metal surfaces with aqueous alkaline solutions to get rid of all kinds of oil, especially rolling oils. The oil on the surface is dissolved and removed by saponification with the help of alkaline surface cleaners usually held at temperatures higher than the room temperature. See Also Degreasing
Class of resins obtained by reaction of polyols and polyacids with oils or mono-functional fatty acids. Their structure is composed of a polyester backbone of polyols and polyacids and monofunctional fatty acids added to the backbone. They are defined as drying, semi-drying and non-drying according to the fatty acid type added to the backbone; and as short oil, medium oil and long oil according to the fatty acid amount.
Class of organic compounds defined by the general formula R-OH, where R demonstrates an alkyl group.
The paint production step at which other input materials in the paint formulation are added to the pigment paste.
Aluminum pigments are used to create a metallic effect on painted surfaces. They are composed of pure aluminum platelets of 10-30 micrometers diameter and of 0,1-0,9 micrometer thickness. See Effect pigments
Viscosity of wet paint at the stage of packaging. It is also defined as delivery viscosity. Packaging viscosity of a paint is determined considering two points:
1) Packaging viscosity should be high enough to prevent settling of fillers, pigments and additives throughout the shelf life of the paint mixture;
2) Packaging viscosity should be low enough to provide homogeneous and easy mixing of the thinner that is added prior to use.
General name for compounds of inorganic or organic nature that are formed by substitution of one of the hydrogen molecules of ammonia with another element or an acyl group (RCO+). In coatings industry, amides of organic nature are utilised in cross-linking of epoxy resins.
Commercial solvent comprised of two of the eight isomers of penthanol structures of which are given below:
Boiling range: 133-139°C; evaporation number relative to ether: 65; specific gravity: 0,812-0,817; refractive index: 1,410-1,411; flash point: 43°C
Compounds formed by exchange of one or more hydrogen groups of ammonia (NH3) with hydrocarbon groups. In case of a single hydrogen exchange, primary amines (RNH2); double hydrogen exchange secondary amines (R2NH); and in case of triple hydrogen exchange tertiary amines (NR3) are formed. They are commonly used for pH adjustment and as hardeners for epoxy resin based paints.
Class of resins formed by reaction of formaldehyde with amino functional groups of compounds such as melamine, urea and benzoguanamine. The resulting resins undergo etherification with alcohols to promote solubility in hydrocarbon solvents and also to enable cross-linking reactions with hydroxyl and carboxyl functional groups on other resins during film formation. Most commonly used amino resins, listed in order of consumption amount, are urea formaldehyde resins, melamine formaldehyde resins and benzoguanamine resins.
Type of electrophoretic coating in which the object to be coated is connected to the electrolysis circuit as the anode and, thus, is coated with the negatively charged paint molecules. See Also Electrodeposition coatings
Crystalline form of titanium dioxide with a lower refractive index (2,488) compared to that of rutile form (2,609) the other crystalline form. Therefore, considering the refractive index of organic binders are generally between 1,40 and 1,60, hiding power of films with anatase type is much less than that of films with rutile type titanium dioxide.
Slowdown of electrochemical processes in an electrolysis circuit, as a result of increased circuit resistance due to accumulation of a liquid or gas layer with a comparably high electrical resistance on anodic surface.
The electrode in an electrochemical circuit where oxidation reaction occurs.
Coatings applied to submerged surfaces in order to avoid accumulation of certain organisms, their residues and the fouling associated with those residues.
Coatings with the main function of protecting the applied surface against corrosion. Anticorrosive paints avoid corrosion through the binders, pigments and additives in their composition. Water-resistant binders with good metal adhesion, anticorrosive pigments inactivating and protecting the metal surface, additives improving the water-resistance or protecting the metal by electrochemical means are used for anticorrosive coating purposes.
Functional pigments added to the paint formulation in order to improve the corrosion resistance of the paint. Most widely used anticorrosive pigments are: chromates, phosphate, phosphosilicate and borosilicate salts, having controlled water solubilities and inactivating the metal surfaces; zinc powder, cathodically protecting the coated metal surfaces; and micaceous iron oxide (MIO or MIOX), having a plate-like structure and acting as a water barrier for metal surfaces.
Type of coating applied between the primer and top coat in heavy duty coating applications in order to obtain the adequate total coating thickness.
Coating defect described by the insufficient adhesion observed between the successive layers of a coating system. Successive application of chemically incompatible layers, and degradation of surface active compounds due to overbaking of lower layers can be typical factors causing intercoat adhesion failure.
Process of keeping the oven-baked wet paint at a lower temperature before baking, to ensure that fast evaporating solvents leave the coating film. Also called “pre-drying”.
Although it is found as a tree in hot and reserved areas, it grows as a shrub in colder climates. Typically, its wood is soft and durable against water, decay and worms. Used in the manufacture of pencil. Its timber is used as railway sleeper. Eight types of Juniper trees are grown in Turkey.
Common name of strong solvents -with a benzene ring on their structure- for dissolving many of the binders, especially alkyd, polyester and acrylic resins. They are obtained from distillation of fossil fuels, especially from high aromatic content petroleum (e.g, Toluene, Xylene, Solvent naphtha etc.).
Chemical name: 2,4-pentanedion
Boiling point: 140ºC, Specific gravity: 0,975, Refractive index:1,452, Flash point: 34ºC
Strong solvent for cellulose derived resins, polyvinyl acetate, short oil alkyd resins and natural resins.
Chemical name: Propane-2-on, dimethylketone
Boiling point: 56,2°C; evaporation number relative to ether: 2,1; specific gravity: 0,791; refractive index: 1,3587; flash point: <-20°C
Measure of amount of acid groups present in a chemical. In coating industry, acid value of binders are widely mentioned. Acid value is defined as the amount of potassium hydroxide (KOH) in mg needed to neutralise the acid groups present in 1 gram of solid resin (e.g. 30 mg KOH/g solid resin).
Endurance/resistance of coating films to the harmful effects of acids.
Type of catalysts that are most widely used for the polimerisation of amino-formaldehyde resins with some other resins such as alkyds, polyesters and acrylic. Weak organic acids of low water solubility are prefered in order to prevent weakening of water resistance of the coating.
Removal of oils and oxide layers on a surface with acid solutions, either by saponification of oils to obtain water soluble soaps or by formation of water soluble salts from oxides. Chromic acid and phosphoric acid are especially prefered for surface cleaning because they form metal chromate or metal phosphate layers strongly adhering to the metal and behave as electrochemically inactive metals rather than dissolving the metal oxide layers like most of the other acids do.
Additives, with both hydrophilic
parts, that establish secondary bonds with waterborne coating binders by means of the repulsive forces applied by water to their hydophobic parts. These secondary bonds cause a viscosity increase that can be easily reversed by shear.
The first pigmented layer of a multi-layer coating system.
Measurable thinning of an organic coating film due to succesive mechanical destruction such as scratching and impacts.
Measure of endurance/resistance of organic coatings to abrasion.
Excess hardening of a high temperature cured coating as a result of curing for a longer time and/or at higher temperatures than required.
Breaking of the wet paint into tiny droplets while being sprayed onto the surface. In air spray applications, droplets of 20-50 micrometers are obtained from atomization with the help of high pressure air. In airless spray applications, paint particles, compressed under 5-35 atm pressure, are broken into smaller pieces by the air molecules they collide with after leaving the nozzle. However, in airless spray applications, an atomization fineness of 70-150 micrometers is considered satisfactory.
Vegetable oil obtained from sun flower oil seeds, and used widely in food industry and in production of alkyd resins. It is a semi-drying oil due to the existence of 52% di-unsaturated linoleic acid and 29% mono-unsaturated oleic acid in its structure.
Multilayer coating applied to the back surface of the mirror in order for the mirror to perform its function. A thin layer of copper coating is applied to protect the silver coating, that enables the reflection on the mirror surface, from corrosion. Mirror coatings are applied to protect the mentioned copper coating from corrosion under humid conditions present in bathrooms etc., where mirrors are widely used.
Percentage ratio of the amount of reflected light from a surface having the same angle with the normal as the light coming to the surface, to the total amount of light coming to a surface.
Percentage ratio of water vapour amount in a gas to maximum water vapor amount the gas can contain (saturation amount) at the same temperature. Relative humidity of air is frequently mentioned.
Chemical substance used to bind the input materials in the organic coating and provide adhesion of the coating film to the application surface as a rigid and continuous film. Binders commonly have polymeric structures, while, less commonly, they may have oligomeric or monomeric structures.
Coating defect described by dull or blurry appearance of topcoat due to the migration of some of the binder to the previous wet paint layer in wet on wet applications.
Type of accelerated test to determine the performance of organic coatings in preventing the corrosion of the metal surface they are applied to. Different from the standard Salt Spray Test
, the aqueous solution sprayed on the coated panel includes 0,025% copper chloride dihydrate, in addition to the 5% sodium chloride.
Name used to describe the tanks utilised to balance the ships by adjusting the center of gravity.
Coating defect described by the crater appearance caused by a fluid having a lower surface tension than the coating system. In fish eye defect, there should be no solid residue observed in the center of the crater, which is usually caused by an oil or silicon droplet, or an undissolved lump of polymer.
Test performed to measure the degree of adhesion of the organic coating film to the surface after application and drying of the coating. Adhesion performance is checked by adhering a tape to the thoroughly cut coating film and pulling away rapidly to determine whether the coating comes off and if it does, to what extent it does.
Natural ore of barium sulfate: (BaSO4). It has rhombic crystal structure; refractive index: 1,64; specific gravity: 4,25-4,50; oil absorption: ~10 g/100 g baryte. The micronised filler, obtained from grinding of the natural ore, is a widely used matting agent for cost reduction purposes because of its low oil absorption value and high density especially when price per weight is important.
General name for chemicals that activate the unsaturated reactive molecule by converting the molecule to a free radical, an organic cation or an organic anion during addition polymerization. Most widely used initiators are, peroxide compounds, azo compounds, alkaline metal alkyls and boron trifloride. The initiators that start to act under the influence of light energy (e.g. UV) are called photoinitiators.
Intermediate coating applied on dried primer layer, mainly in OEM and car refinish paints. Varnish is applied on base coat while it is still wet to obtain an appealing surface and protection. Usually, base coats also contain metallic and pearl pigments.
During the paint drying process, honeycomb-like hexagon cells are formed by the convectional flow due to the solvent evaporation caused by the temperature differences. These hexagonal cells are called Bénard cells. Film defects such as floating
occur due to the formation of Bénard cells of various sizes.
Liquid that is obtained from distillation of raw petroleum and that includes mainly aliphatic hydrocarbons. While the main usage is in internal combustion engines, it is also used as a coating solvent. Besides the general purpose gasoline, some special gasoline types, distilled at different temperature intervals, are also used as coating solvents. Depending on the properties of the raw petroleum, gasoline can chemically contain more than 120 hydrocarbon types. Many of those hydrocarbons have saturated structures with 4 to 12 carbons on their backbone.
Compound used in the production of benzoguanamine formaldehyde resins.
Chemical name: 1,3-Diamino-5-phenyl-2,4,6-triazine
Melting point: 227°C
Class of resins synthesized from polymerization of benzoguanamine with formaldehyde. Their use in organic coatings is limited to some oven-cured primers.
Mono-functional organic acid used as a chain stopper to control the molecule growth in the production of alkyd and polyester resins.
Melting point: 121°C
Method for producing paints, containing more than one type of pigments and/or fillers, where pigments and/or fillers are dispersed by grinding together.
Type of coatings used for painting of household goods such as refrigerators, ovens, dishwashers, washing machines and driers. While wet coatings had been commonly used for this application until fifteen years ago, powder coatings
are widely used presently.
Type of vegetable oil obtained from linseed and used in organic coatings for almost a thousand years. Linseed oil contains 52% tri-unsaturated linoleic acid, 16% di-unsaturated lionleic acid and 22% mono-unsaturated oleic acid in its structure. Because linseed oil is a drying oil, it is directly used as paint binder, as well as in drying alkyd resin production.
OICA (The International Organization of Motor Vehicle Manufacturers) defines the passenger cars as: Vehicles used for passenger transportation purposes with at least four wheels and 9 seats -including the driver seat- are defined as “passenger cars”. See Also Motor vehicles
Type of polyol obtained from the reaction of phenol and acetone under strongly acidic conditions and used for production of epoxy resins. It is also the main building structure of polycarbonate polymer.
Chemical name: Diphenylolpropane
Melting point: 155°C
Type of polyol obtained from the reaction of phenol and formaldehyde under strongly acidic conditions and used for production of epoxy resins with smaller molecular weight and higher functionality.
Chemical name: Dihydroxydiphenylmetane
Melting point: 163°C
General name for oils stored in seeds, fruits and bodies of plants, and obtained from esterification reaction of three vegetable fatty acids with the three hydroxyl group of glycerine. Most widely used vegetable oils in coatings industry are soybean oil, sunflower oil, linseed oil, tung oil, olive oil and castor oil. See Also Triglycerides
Chemicals used to prevent growth of various bacteria, fungi and maggots in especially waterborne coatings either in the package or after application. Most widely used biocides are formaldehyde, formaldehyde derivatives, tin compounds and basic quarternary copper compounds.
Synthetic barium sulfate (BaSO4) obtained starting from baryte, forming first barium sulfur (BaS), followed by reaction of BaS with sodium sulfate (Na2SO4). After isolation and grinding, Blanc fixe is used as high quality filler.
Isocyanate resins, which react with hydroxyl and amine groups at room temperature, are blocked by volatile compounds to be able to produce single component oven-cured coatings. For blocked isocyanate resins, blocking chemicals that evaporates at a temperature a little lower than the oven temperature are chosen.
Coatings used in high speed lines to coat coils (metals shaped into foils and winded as a roll) resulting in flexible and high resistance coatings. See Also Pre-coated metal (PCM)
Consists of a cylindrical shape metal cup. There are various steel discs on the rotating mill along the axis of the cup. Hard beads of 0,5-3,0 mm diameter are placed in the mill together with the pigment paste to be grinded. The pigment agglomerates between the moving beads are grinded with the help of the friction between the beads that are moving with the whirling effect of rotating discs. Until recently, similar mills containing high silica sand instead of beads were widely used. These mills were called sand mills
Part of a ship above its “full load line”. Board surfaces are usually dry, however they are wetted from time to time by spatters or water vapor and they are always exposed to oxygen and sunlight.
1) Organic coating material that contains coloring substances called pigments; 2) Organic coating film that contains pigments and is already coated on a surface. (Note: Most of the time the term “paint” is used in place of “organic coating
”, since it is the most widely used organic coating)
“Destructive test” equipment used to determine the layer thickness values of different layers in a coating system separately by punching a conical hole in the paint film and observing the layers with a scaled magnifier. A paint borer consists of a right triangle shaped steel knife rotating around its perpendicular edge and a scaled magnifier.
Auxiliary material used to remove the dried coating film from the surface. Paint removers contain strong solvents gelled by various binders and additives, and provide removal of the coating film by inflating/swelling effect of solvents. Paint removers should be miscible with water to allow rinsing of the swelled coating.
Material obtained by coating the coils with high temperature cured coatings on high speed lines. Pre-coated metal is an interesting solution for: 1) quality and durability due to the usage of specially designed coatings 2) environment due to burning of the released VOC
in after-burners and recycling as energy 3) efficiency due to high speed application.
Coloring chemical substance in the form of small particles so as not to cause the scattering of light, and is soluble in water and some organic solvents.
Dimensional change of especially wood and metal in the form of shrinkage and expansion. Dimensional changes on metal surfaces are expansions and shrinkages occuring at varying ambient temperatures related to the expansion coefficient. For wood surfaces, dimensional change is due to the swelling of the material by capturing water at humid conditions or shrinkage due to loss of humidity at dry conditions.
Test that aims to determine hardness of a coating film by measuring the depth of a V-shaped cavity formed by running a sharp metal wheel carrying a constant weight on dried coating film.
The coefficient indicating how fast a solvent or a solvent blend evaporates compared to a reference solvent. Diethyl ether and butyl acetate are widely used as referance solvents. See Also Evaporation number
“Evaporation number” is defined as the ratio of time spent to completely evaporate a certain amount of solvent at 20°C temperature and 65% relative humidity, to the time spent to completely evaporate the same amount of reference solvent under same conditions. Diethyl ether is widely used as the reference solvent in Europe. In America and Far East, the most widely used reference solvent is n-butyl acetate.
Resistance of a coating film to cracking, breaking and delamination when bended together with the metal surface. Bending resistance is measured by bending the panel around a cylindrical or conical surface or by directly folding the panel. These tests are called cylindrical bending test, conical bending test and T-Bend test, respectively.
In electrophoretic coating, it is required that coating reaches to the remotest parts of the coated object starting from the shortest distance between the electrodes. The ability of electrophoretic paints to coat the remotest parts of the coated object is called throwing power. Coating of the remote parts usually requires bending of electrical field lines that normally follow the shortest distance between the two electrodes.
Alcohol which dissolves urea/melamine formaldehyde, polyvinyl acetate, Polyvinyl butyral resins in addition to natural resins. It can dissolve a broad range of polymers when used with aromatic solvents.
Chemical name: n-butyl alcohol or butan-1-ol.
Boiling point: 117,7°C; Evaporation number based on the ether: 33; Specific gravity: 1,809-1,811; Refractive index; 1,3993; Flash point: 35°C
Ester which dissolves almost all types of cellulose derivatives, polyester, acrylic and short oil alkyd resins.
Chemical name: Acetic acid n-butyl ester butile
Boiling point: 126,5°C; Evaporation number based on the ether: 14; Specific gravity: 0,882; Refractive index: 1,3951; Flash point: 25°C
used to retard drying of nitrocellulose, epoxy based solvent-borne coatings and as a “heavy” co-solvent in waterborne organic coatings at low quantities such as 1-2 %.
Chemical name: Diethylene glycol mono butyl ether; 2-(2-butoxy-ethoxy) ethanol ( also called Butyl carbitol)
Boiling point: 230°C; Evaporation number relative to ether: ~1200; specific gravity:0,954; refractive index: 1,4322; flash point: 105°C
used to retard drying of cellulose derived resins, polyester and short oil alkyd based solvent-borne coatings at low quantities such as 1-2 %.
Chemical name: diethylene glycol mono ether acetate (also called butyl carbitol acetate)
Boiling point: 247°C; Evaporation number relative to ether: >1200; specific gravity:0,979; refractive index: 1,4262; flash point: ~108°C
“Slow” solvent used as a co-solvent in waterborne organic coatings and also to dissolve nitrocellulose, polyester, epoxy resins.
Chemical name: Ethylene glycol mono butyl ether; 2-Butoxyethanol (also called butyl cellosolve or butyl oxitol)
Boiling point: 171°C; Evaporation number relative to ether: 160; specific gravity:0,901; refractive index: 1,4196; flash point: 60°C
“Slow” solvent that has a dissolving effect on some cellulose derivatives and polyester resins.
Chemical name: Ethylene glycol mono butyl ether acetate; butoxy ethyl acetate (also called butyl cellosolve acetate or butyl oxytol acetate)
Boiling point: 192°C; Evaporation number relative to ether: 190; specific gravity:0,941; refractive index: 1,4139; flash point: 75°C
Melamine formaldehyde resins modified by reacting with butanol. Butylated melamine formaldehyde resins are widely used because of their compatibility and high film quality due to their comparably low surface tension. However, they are not used in high solid systems because of their high molecular weights.
Transparent or semi-transparent inorganic substance, main raw material of which is silica (SiO2). There are sub-groups such as soda-lime-silica glass, borosilicate glass, phosphate glass and crystal (lead glass).
Temperature at which amorphous polymers undergo an evident transformation from brittle to elastomeric behaviour upon heating.
Mathematically structured color identification system developed by International Commission on Illumination (Commission Internationale de l’Eclairage, CIE). The system is based on the fact that there are three types of conical shaped light perception cells in human eye and those cells are sensitive to blue, green and red lights. Taking this fact in to account, each color is expressed in terms of three variables; L, a and b. Because it takes the light and the observer into account together with the object, CIE Lab color system gives more sensitive and reproducible results compared to the other color identification systems. See Also Color identification systems
Transparent and wax-like substances that fill the pores/pinholes on a surface upon polishing increasing the gloss of a surface. However, in Turkey, varnishes applied on wood surfaces are also referred to as polishes.
Bells rotating at a speed of 25,000-60,000 rpm are used for spray applications, which are especially utilised in otomotive OEM coatings. Paint is broken into tiny droplets as a result of the centrifugal force arising from high rotation speed and sprayed on the application surface. Electrostatic methods are used for these kind of applications due to transfer effectiveness.
Polymerization of organic coating binders with each other is as effective as the solvent evaporation for the film forming (i.e. drying) process. Polymerization by binding to each other is called “crosslinking”.
Crosslinked polymers are formed by the reaction of at least two initially linear or branched polymers over their active functional groups. Functionalities of the monomers constituting these polymers cannot be less than 2, and at least one of the monomers should have a functionality of F=3 or more. Crosslinked polymers are of thermosetting nature.
Visual effect created by using metalic paints containing silicone based incompatible surface additives. Local surface energy differences caused by the incompatible nonhomogeneous silicone surface additive, creates a hammered appearance on the dry coating film.
Name given to putties that unsaturated polyester resins or epoxy resins are used as binders and that reaches to very high stiffness after spatula application and drying.
Frame-like appearance caused by higher coating thickness on the edges of the coated object. This is due to the fact that there is more interface on the edges, therefore evaporation occurs faster on the edges. Since solvents have lower surface tension values than the rest of the paint formulation, surface tension of the remaining wet film is higher at edges, and consequently, paint accumulation occurs on these parts. See Also Maragoni effect
Inorganic coatings applied by dipping or spraying to enhance the adhesion of coatings to metal surface and to improve the corrosion resistance. See Also Phosphating
Zinc soap, not soluble in paint solvents, used as an additive in paints and varnishes for matting and easy sanding with sandpaper.
The grains on the wood surface are destroyed during sanding. The grains on the surface are filled with dilute thermoplastic aqueous varnishes by a process called sizing. Destroyed grains swell and jut themselves out of the surface during sizing. Sanding is performed after flash-off of sizing varnish; a second sanding should be performed to remove these protruded grains. Consequently, wood surface becomes ready for paint application.
Formation of irreversible little cavities on the organic coating film surface is called scratching. Organic coatings with high “scratch resistance” either have high resistance to scratching or scratches dissappear after a while due to the nature of the coating.
For crosslinking organic coatings, if the crosslinking occurs at room temperature, reactants of crosslinking are packed separately. Coatings, packed as two or more separate components, are called multi-pack coatings. See Also Two-pack coatings
Coated surfaces, giving a gloss value over 80 when measured at 60° with a glossmeter, are called high gloss paints.
Settling of pigments, fillers and other solid particles in the paint formulation under the influence of gravity, leaving the suspension state. If the settled particles can be homogenized by mixing, the phenomenon is called “soft sedimentation”. If the settled particles cannot be dispersed even with vigorous mixing, the phenomenon is called “hard sedimentation”.
Organic liquid of mostly volatile nature that is used in the coating formulation to dissolve the binder.
Coatings having viscosities low enough to enable the application even if they do not include solvents in their formulations. Solvent-free liquid coatings are produced with binders obtained from low molecular weight polymers, oligomers or reactive monomers. (e.g, Radiation curable coatings
, solventless epoxy coatings etc.)
Removal of dirt, oil or other contaminants from the paint application surface by using strong oil dissolving solvents.
Coatings containing binders that are soluble in organic solvents.
Coatings containing binders that are soluble in organic solvents.
Solvent or solvent blend property that describes the capability of the solvent/solvent blend to dissolve a polymeric binder and to decrease the solution’s viscosity.
Parameters, proposed by Hildebrand based on the structural properties of a chemical, demonstrating the dissolving characteristics of a chemical. Later on, Hansen developed a more advanced three component (dispersion forces, polar forces and hydrogen bridges) “three dimensional solubility parameter” system.
Coating application performed by dipping the object into a vessel or tank filled with wet paint at application viscosity. Possible coating defects such as sagging; settling, foaming and non-homogeneous film thickness can be avoided by complete control over application variables.
General name for polymers having three or more polymer segments connected to a branch point. They are formed by reaction of di-functional monomers bearing at least one of their functional groups on their central parts allowing branching. For step growth polymerization, small amounts of monomers with F=3 is used. For addition polymerization, small amounts of initiators with tendency to branch or monomers with F≥4 are used. Some common branched polymer types are shown below:
Branched polymers can be of thermoplastic or thermosetting nature.
Resistance of a coating film to surface defects such as ripping and delamination even under impacts that can cause physical changes in substrate. For this purpose, a ball of standard mass is dropped onto coated surface from gradually increasing altitudes. The impact strength is described as product of ball mass and drop distance at the point of first visible damage. (e.g., kg.cm, lb.ft etc.)
Grinding of pigment agglomerates and aggregates close to their primary particle sizes after dispersion process. See Also Controlled flocculation
Castor oil derivative, obtained by dehydrating castor oil, containing two conjugate double bonds and demonstrating drying oil properties. See Also Castor oil
Natural or synthetic oxides of iron are considered to be the oldest and the most widely used pigments. Oxides of the Fe2O3 structure are red, Fe2O3xH2O structure are yellow, Fe3O4 structure are black, and different mixtures of FeO and Fe2O3 are used as brown pigments.
Coatings with superior corrosion and water resistance used for yachts, commercial and naval marine vehicles and containers for sea transportation.
Big metal box used for sea transportation of goods. Sea containers are 20 ft (~6 meters) or 40 ft (~12 meters) long.
Coatings used for interior and exterior surfaces of sea containers. Primary function of exterior coatings is high resistance against corrosion and water. For this purpose, epoxy based primers and, acrylic, chlorinated rubber or alkyd based top coats are used. Interior coatings are expected not to be affected by the dry load carried in the container and to prevent contamination of the dry load by container’s interior surface or the coating itself.
Flexible coatings used for tanned leathers of animals such as cattles, pigs and sheep to obtain a more appealing look.
Test performed by pushing a knob with a constant speed against the back side of a coated panel causing deformation. During the test, also called Erichsen deformation test, knob is stopped when the first sign of crack formation is observed, deformation depth is measured in mm and this value is defined as deep cupping resistance.
In-depth filtration is performed using porous filtration media (e.g, porous cartridges) with a thickness much higher than the desired particle size in the paint. Undesired particles are held in the pores of the filter and, thus the paint is filtered.
Resistance of organic coatings against UV, water, oxygen, chemicals, microorganisms, mold, temperature, temperature differences, wind and abrasives.
Most reliable tests, performed to measure the resistance of organic coatings to external factors, are the ones that are held at natural outdoor environment. These tests are preferrebly carried out at test stations located in places where severe weather conditions prevail (e.g, Florida, USA; Arizona, USA; Okinawa, Japan; North Sea Coast, Europe).
Solvent, of both ketone and alcohol character, obtained from condensation reaction of two acetone molecules and utilized in cellulose derived resins and epoxy based coatings.
Chemical name: 4-hydroxy-4-methyl pentane-2-one.
Boiling point: 167,9°C; evaporation number relative to ether: 135; specific gravity: 0,938; refractive index: 1,4241; flash point: 58°C
Solvent that is obtained from blending of dimethyl glutarate, dimethyl succinate and dimethyl adipate and that is a strong solvent for polyester resins. Blending ratio of three esters differs according to the producer. Typical composition and some properties of a widely used product of Invista, named DBE, are given below:
Typical chemical composition:
59% Dimethyl glutarate
20% Dimethyl succinate
Boiling range: 196-225°C; evaporation number relative to ether: >100; specific gravity: 1,092; refractive index: 1,423; flash point: 103°C
Fluids that undergo a viscosity increase upon exposure to shear force (e.g., mixing or applying pressure) See Shear thickening fluids
Type of roller applications, which are based on coating flat panels with rollers on a moving conveyer. In direct roller applications, rotation direction of “application roll” is the same as the conveyer’s moving direction. Having a lower shear than reverse roller application, direct roller application provides good results in primer and non-glossy top coat applications. See Also Reverse roller application
, Roller coating applications
1) Scattering of a substance in another substance in small particles.
2) Homogeneous and stable mixture obtained by dispersion process.
Process of preserving the homogeneous and dispersed state of the pigments in the paint. Stabilization is achieved by two basic mechanisms: (a) Pigment interfaces are electrically charged using convenient additives, therefore repulsion force between particles of similar charge keeps the pigments from agglomeration; (b) Polymeric dispersion additives carrying pigment-loving groups prevents the pigments from agglomeration by forming a polymer layer around the pigment particle (: steric hindrance)
A tree belonging to the olive family with a hard and precious wood. White Ash has brown sap wood and large pore white-yellow heartwood in addition to its distinctive growth rings. It is used in furniture production and it has a specific gravity of 0,75 g/ml.
Color identification system that takes four basic colors, which are saturated and not darkened with black, as reference. For NCS, yelow, red, blue and green standarts are formed with the above mentioned properties. Various color tones are obtained by mixing the standards at different ratios. Each color can be mixed with transparent varnish to obtain several saturation levels. In addition, these colors can be darkened with black in various ratios. Colors obtained by these methods are named by NCS as follows: 2080-R70B means color contains 20% black, 80% saturated and its hue is composed of 70% Red (R:Red) and 30% Blue (B:Blue). See Also Munsell color system
, Color identification systems
Drying of a coating film to a point where it feels dry when touched. Touch-free drying tests are performed by; (a) Applying an average pressure on the drying film with a finger, (b) Observing whether there is paint residue on a piece of cotton pressed to the surface with a pressure of 250-500 gr/cm²
Since high amount of paint is required on production lines such as automotive products and household equipment lines, transfer of paint to the application point is done with circulation routes. There are various hydraulic and mechanical factors affecting the paint stability in these circuits/routes that consist of pipes, elbows, valves, pumps etc. Circulation stability determines the resistance of paint to such factors.
Transparent primer, applied on, especially, wood surfaces when a transparent coating system is desired.
General name for micron-sized powder coating input materials, many of which are comprised of grinded natural minerals (baryte
) and some of which are obtained by synthetic methods (Blanc Fixe
). While main reason for using extenders is cost reduction, they can also be used to improve certain properties. For extenders used in pigmentless coatings, it is crucial that extenders are also colorless and have refractive indicis close to the binder’s refractive index in order for the transparent look not to be affected.
Rocks formed by precipitation of calcium and magnesium carbonate together are called dolomites (CaCO3.MgCO3). Refractive index: 1,60; Specific gravity: 2,90. Filler material obtained by grinding of dolomite is used in exterior architectural coatings.
Coating defect defined by dull, non-homogeneous or shady appearance caused by accumulation of certain substances on coating surface. Bloom is usually caused by foreign substances such as non-transparent oils or waxes.
Name given to composite material group obtained by mixing unsaturated polyester resin with fiber, sand etc. to improve mechanical strength. Fiber reinforced polyesters (also called FRP or Glass) are the most widely used unsaturated polyester based composites.
Coating application device that sprays the wet paint fed to its surface on to the paint application surface as atomized droplets with the effect of the centrifugal force generated by rotation at 1000 rpm or more. Rotary discs are most widely used for home appliances and other metal goods
Wooden sheet that’s smooth on one side and porous on the other side. Hardboards are produced by a process in which pine, oak, beech chips are made fibrous by swelling and shaped by wet-processing after some adhesive is added.
Spray guns designed to provide the atomization of paint using less air by mixing the paint in the gun with air at less than 0,7 atm positive pressure. LVLP spray guns are used for high transfer efficiency and high surface quality.
Insufficient drying of high temperature cured organic coatings as a result of insufficient temperature or exposure times.
Natural or synthetic polymer that can be elongated to at least double its length at room temperature and can recover to its original length after removal of force. Vulcanized rubber usually demonstrates elastomeric behaviour.
Term generally used in coatings industry to describe the electrical resistivity of wet paints. In order for the wet paint to be sprayed by electrostatic methods, it has to reach to the cathodic surface with the effect of electrical attraction forces. For this purpose, electrical resistance of the wet paint should be below a certain value. In other words, the wet paint has to be sufficiently conductive. See Also Conductivity
Coating of an object with paint particles after dipping into an emulsion paint bath as an electrode and applying external current.
Process of migration of electrically charged emulsified particles to the oppositely charged electrode and deposition on the electrode under an electrical current. If the material migration under the influence of the electric field occurs by movement of (+) charged particles to cathode, the process is called cataphoresis
. Similarly, if (-) charged particles move towards the anode, the process is called anaphoresis.
Coatings, on generally steel based surfaces, obtained by connecting the surface to an electrolysis circuit as the cathode leading to formation of a thin zinc layer on the surface. Electrogalvanic coatings provide corrosion resistance to the steel based surface with the help of the thin zinc layer.
Spray coatings performed by negatively charging the paint or surrounding the sprayed paint with ionized air (:corona) and connecting the application surface to the circuit as the positively charged electrode. Electrostatic spray coating is used for both wet and powder coatings because of the minimum transfer loss as a result of the movement of particles directly to the surface with the electrical attraction forces.
Objects made of aluminum are connected to an electrolysis circuit as the anode and an oxide layer with good adhesion, high barrier and corrosion resistance is formed. This process is called eloxal (Electrolytic Oxidation of Aluminum) and the resulting surfaces are called eloxal surfaces.
Saturation of a substance with a fluid by penetration of the fluid into the substance.
System formed by suspension of a liquid in another immiscible liquid as droplets larger than a colloidal state.
Compound obtained by starting from chlorination of propylene and used in production of epoxy resins and epichlorohydrin rubber.
Chemical name: Chloromethyloxirane
Boiling point: 116°C
Organic coating resins obtained by reaction of Bisphenol A based epoxy resins with fatty acids; solvent or water thinning versions can be produced. Air drying or oven drying epoxy resins can be synthesized depending on the fatty acid type used.
Resins carrying two or more extra epoxy groups at the ends of their polymer chains. The most widely used type is produced by reaction of epichlorohydrine (chloromethyl oxirane) and bisphenol A (diphenylolpropane). Liquid or solid epoxy resins can be produced depending on the length of the polymer chain. For organic coatings, epoxy resins are reacted with polyamides, polyaminoamides, isocyanate compounds, amino resins and ketimines. Epoxy resins are used in production of organic coatings with superior adhesion, chemical resistance and corrosion resistance.
Epoxy based coatings in which ketimine compounds are used as hardeners. Typical epoxy-amine crosslinking reaction occurs as a result of decomposition of ketimine to amine and ketone in the presence of water or moisture. See Also Moisture curing coatings
Two component coatings having one epoxy resin based and one polyamide resin based component.
Certain mechanic tests applied to determine the elasticity of dry coating film. Elasticity measurement tests (deep-cupping, bending, impact) are also used to measure toughness.
Organic compounds formed by condensation reaction of organic acids and alcohols.
Minimum amount of energy required to initiate a chemical reaction at a certain temperature.
Ethanol, just like methanol, is not a strong solvent for most of the polymers. However, blending with aromatics causes a strong solvent effect.
Chemical name: Ethyl alcohol
Boiling point: 78,3°C; evaporation number relative to ether: 8,3; specific gravity: 0,789; refractive index: 1,3614; flash point: 12°C
Type of ester that is a strong solvent for a wide range of polymers including many cellulose derived resins, polyvinyl acetate and polyesters.
Chemical name: Acetic acid ethyl ester
Boiling point: 77,2°C; evaporation number relative to ether: 2,9, specific gravity: 0,901; refractive index: 1,3725; flash point: –4°C
Tail solvent of ether alcohol structure, used to retard drying of cellulose derived resins, epoxy resins, polyester resin based coating systems and water-borne coatings at low quantities such as 1-2 %.
Chemical name: Diethylene glycol mono ethyl ether; 2-(2-ethoxyethoxy)ethanol (also known by the commercial name Carbitol)
Boiling point: 202°C; evaporation number relative to ether: ~1200, specific gravity: 0,990; refractive index: 1,4270; flash point: 90°C
Tail solvent used to retard drying of cellulose derived resins, polyester resins and short oil alkyd based coating systems at low quantities such as 1-2 %.
Chemical name: Diethylene glycol mono ethyl ether acetate; 2-(2-ethoxyethoxy) ethyl acetate.
Boiling point: 217°C; evaporation number relative to ether: >1200, specific gravity: 1,009; refractive index: 1,4213; flash point: 98°C
Ether alcohol used to dissolve nitrocellulose, polyvinyl alcohol, epoxy resins and many natural resins. Its use is limited due to possible health risks.
Chemical name: Ethylene glycol mono ethyl ether, ethoxy ethanol (also known as Cellosolve or oxitol)
Boiling point: 135°C; evaporation number relative to ether: 43, specific gravity: 0,930; refractive index: 1,4081; flash point: 42°C
Ether acetate also used to dissolve polyester and short oil alkyd resins, besides being used for the same applications as ethyl glycol. Its use is limited due to health concerns.
Chemical name: Ethylene glycol mono ethyl ether acetate; ethoxy ethyl acetate (also known as Cellosolve acetate).
Boiling point: 156,2°C; evaporation number relative to ether: 60, specific gravity: 0,975; refractive index: 1,4058; flash point: 51°C
Solvent used below 10% in organic coating formulations when a late evaporating polar tail solvent is required. Also called isooctanol or isooctyl alcohol.
Boiling point: 184°C; evaporation number relative to ether: ~600; specific gravity: 0,833; refractive index: 1,4328; flash point: 74°C
Water soluble cellulose ether resins obtained by reaction of cellulose with ethanol. They are used as binders in water-borne architectural coatings and as thickeners.
Group of coating binders that is obtained by reaction of silica with ethyl groups and that provides high corrosion resistance. Most widely used example is tetraethylorthosilicate monomer. They are used in production of zinc-rich waterborne primers.
Type of polyol that is obtained by hydration of ethylene oxide and is a petrochemical product. It is widely used in making of alkyd and polyester resins. Also widely used in closed circuit anti-freeze solutions.
Chemical name: Ethane-1,2-diol
Boiling point: 197°C; specific gravity: 1,113; refractive index: 1,4310; flash point: 110°C
Type of synthetic rubber. Tailor-made plastics with adjusted strength, flexibility and brittleness are obtained by preparation of alloys of ethylene propylenediene polymer and polypropylene (PP/EPDM) at various ratios. PP/EPDM alloys are most widely used for automotive bumpers.
Chemicals; detergents, alcohols, ammonia, sodium hypochloride, soaps, oils, vinegar etc.; that have destructive effects on coated surfaces of household objects such as furniture, home appliance, electronic devices and parts such as flooring, walls and doors etc.
Paint production step applied to decrease the particle size of pigment aggregates in the fluid medium using mechanical energy. Because grinding of pigments used in wet paints are achieved in liquid media consisting of resin solutions, those processes are also called “wet grinding”.
Upper limit of particle size range obtained after dispersion. Fineness of grind is usually stated using two gauges: Metric gauge based on micrometer and Hegman gauge. e.g, in the case that almost all the particles in a pigment paste or coating are 25µm or smaller, fineness of grind is 25µm in metric gauge and 6 in Hegman gauge.
Laboratory device used to determine the upper limit of pigment size of coatings or semi-finished coatings. Grindometers consist of a steel block with a cavity of varying depth starting from zero depth. The deep end of the cavity is filled with the pigmented liquid and the liquid is scraped towards the shallow end with the help of a knife. Depth of cavity at the point where particles are visible is noted as the fineness of grind.
Part of a ship between submerge levels of empty and fully loaded conditions. Surfaces at boot topping part are exposed to frictional effects by guide boats, piers and buoys. In addition, depending on the loading level, it can be exposed to spattering of sea water or can be fully submerged.
During electrostatic spray applications, electrical field lines, formed between spray gun and coated object, prevent the coating from reaching indentations. Process of formation of electrical field lines in a cage form preventing the transfer of coating to the inner surfaces of the cage is called the “Faraday Cage”.
White and crystalline chemical substance used as raw material for phenolic resins.
General name for resins, formed by reaction of phenol and aldehydes, having outstanding thermal and chemical resistance.
Apparatus used to apply paint by means of its fibers attached to a handle. Brush fibers are prefered to be made of nylon or polyester for waterborne coatings; and of polyester or animal hair for solventborne coatings.
Fiber streaks can be observed right after the application of the paint by brush. If those streaks do not dissappear during drying process, a coating defect named “brush mark” arises. Brush marks can be overcome by lowering the surface tension or viscosity, or by adding slow solvents to the coating system.
Baking of high temperature drying coating systems in high temperature ovens.
Formation of a highly adhering, hard and enduring film as a result of physical (solvent evaporation for wet coatings, cooling for powder coatings) and/or chemical processes after application of wet or powder coating to the surface as a thin layer.
Organic coating raw material used for providing adhesion, internal integrity and strength. See Also Binder
Agglomeration of previously grinded and dispersed pigments as flocculates due to the unstable dispersion process. See Also Flocculate
Pigment lump formed by coalescence of pigments at their edges and containing resin and solvent in their interspaces. Flocculates generally arise from re-agglomeration of previously dispersed pigment particles. See Also Clusters of pigments and extenders
Most of the colored objects absorb some of the light they are exposed to and reflect the rest, while they return the light energy they absorbed to the surrounding in the form of heat energy. There are few objects, however, that return the light energy in the form of light energy. This fact is called flourescence.
Flourescent pigments, after absorbing the UV spectral part of the light, return the UV light energy in the form of a blue visible light together with some heat energy. Therefore, flourescent pigments emit more visible light than they are exposed to.
General name for polymers, structural units of which contain fluoro compounds. Polytetra fluoroethylene (PTFE), polyvinylidendifloride (PVDF or PVF2) and polyvinylidenfloride (PVF) can be mentioned among the main fluoropolymers that are used in organic coatings having superior thermal resistance, chemical resistance and outdoor durability.
Similar to polysiloxane surface additives; fluorocarbon surface additives, having low surface tensions and compatibility with the coating formulation, migrate to the surface to avoid formation of film defects.
Functionality is the total number of functional groups in the molecule of a chemical compound (total capacity for chemical bonding).
General name for groups formed by atoms, present in the structure of a chemical compound, arranged together to have tendency to undergo chemical reactions. (e.g., –OH, –COOH, –NCO, –HC=CH–)
Reactive gas obtained by catalitic oxidation or dehydrogenetion of methanol
Basic structural unit used in production of various resins such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde etc.
Boiling point: –21°C
See Also Paraformaldehyde
Surface treatment performed to improve adhesion of coating to metal surfaces and to reduce corrosion tendency (inactivation) of metal surfaces. Phosphating is carried out either by using iron phosphate solutions resulting in more limited protection or by using solutions containing one or more of zinc, manganese and nickel phosphate salts resulting in thicker coatings. The latter case provides better adhesion and higher corrosion resistance.
Some objects absorb some of the light energy and reflect the rest, while returning most of the absorbed light energy to its surrounding in the form of light energy, similar to fluorescence but with a time lag. This fact is called phosphorescence. See Also Fluorescence
Phosphorescent pigments, following absorption of the UV spectral part of the light, return some of the energy as heat energy; after a time lag they emit the rest of the energy in the form of a blue visible light. Therefore, phosphorescent pigments continue to emit a blue light also after removal of the light source.
Breaking up of polymers (meanwhile dried coating films) into smaller molecules with the effect of visible or UV light.
Chemical substance obtained by oxidation of o-xylene or naphthaline. Phtalic anhydride is the most widely used polyacid in alkyd resin and polyester resin synthesis.
Boiling point: 131°C
Volume unit. Imperial gallon corresponds to 4,54 liters and U.S gallon corresponds to 3,785 liters.
Name for coatings applied by dipping cold rolled carbon steel plates or various carbon steel objects into a melted aluminum, zinc, silicon alloy bath. These coatings are composed of 55% zinc, 43,4% aluminum, 1,6% silicone; and are also known as Aluzinc or Zincalume.
Name given to slow evaporating solvents added to coating formulations to prevent surface defects such as brush mark
s, orange peel
etc. caused by “fast” evaporation of solvent blends during coating applications.
Segment of industrial coatings market that covers the sub-segments which are not classified as seperate technical or commercial groups. According to Paint Research Association (PRA), these sub-segments are as follows: Heavy Duty Coatings, Heating, Ventilation and Conditioning Coatings; Auto Ancillary Industry Coatings; Metal Furniture, Accessories and Connections Coatings, General Metal Industry Coatings. However, since industrial structure in Turkey has some differences with those in highly developed industrial countries, the General Industrial Coatings segment in Turkey, includes some other activity fields which PRA classifies as seperate segments of Industrial Coatings market. In line with this, General Industrial Coatings activities in Kansai-Altan are structured to serve the following sub-segments: Agricultural Vehicle Coatings, Heavy Duty Machinery Coatings, Steel Construction Coatings, Construction Material Coatings, Household Instrument Coatings, General Metal Industry Coatings. See Also Industrial Coatings
Scattering of wet paint particles sprayed by conventional air spray guns to the surroundings after bouncing from the air cushion near the surface or bouncing with the air from the surface. Bouncing effect decreases the transfer efficiency since some of the sprayed coating is not transfered to the application surface.
U.S institution that arranges the standarts, norms and recommendations regarding food and drug. FDA is an important foundation for coatings industry due to the standarts and limitations on coatings applied to food contact surfaces.
Light rays falling on transparent thin plates with a thickness close to wavelength, are reflected separately from top and bottom surfaces of the thin plate. These separately reflected light rays undergo a physical interaction called “interference” and perceived as different colors. These colors, especially observed with pearlescent pigments, are called “interference colors”.
Heat energy required to completely evaporate a unit amount of liquid heated to its boiling point under 1 atmosphere pressure. (Unit: cal/g)
Compounds, obtained from reaction of glycol ethers with acetic acid, having both ether and hydroxyl bonds. (e.g, Butyl glycol acetate = Ethylene glycol monobutyl ether acetate). Glycol ether esters are among the most widely used oxygenated solvent groups.
Compounds, formed by reactions of glycols (e.g, ethylene glycol) having both ether and hydroxyl bonds. For instance, structure of ethylene glycol monobutyl ether is given below. Glycol ethers are among the most widely used oxygenated solvent groups.
Glycerine occurs naturally in structures of vegetable and animal fats. Synthesis is achieved by oxidation of propylene. It is the most widely used polyol in alkyd resin production.
Chemical name: Propane-1,2,3-triol or 1,2,3-propanetriol
Melting point: 18,2°C; boiling point: 290°C
Spectrometer that carries out color measurements via detectors placed in such a way that enables measuring of different reflection angles from a colored surface. Goniospectrometers are used to measure colors that change at different angles, especially colors of coatings containing metal or pearlescent pigments.
For basecoats containing aluminum and pearlescent pigments, partly cloudy, low glitter, low luminosity surface appearance is observed if factors such as low film viscosity, nonhomogeneous film thickness etc. prevents the aluminum or pearlescent pigments to be alligned parallel to the surface. This phenomenon is called mottling or cloudiness.
Pigments added to coating formulations to provide an appealing look, besides coloring the coating. For this purpose, aluminum pigments and mica based pearlescent pigments of platelet shape are widely used. There is a special aesthetical expectation from basecoat applications containing metalic or pearlescent (or micaceous) pigments: the flip-flop property. This coating property, formed by parallel allignment of aluminum or pearlescent platelets to the surface, leads to a mirror-like appearance when looked from the front, and to a dark color appearance when looked from a very low angle. Transparency of the film formed by binders enhances the flip-flop effect.
DOI is one of the three concepts designating the reflected image quality, therefore, low DOI is an important defect for automotive OEM and car repair coatings. Low DOI is revealed by observation of scattering on the vicinity of the main light beam reflected with an angle of 20° from the varnish surface. However, scaterring in low DOI occurs in a much narrower angle interval than that of haze defect. Low DOI is perceived as reduction in sharpness and distinctness on the edges of the reflected image. Measurement of DOI is performed by DOI-meters produced by equipment producers. Low DOI can arise from light scattering caused by crystalline additives or binders in the coating film, or by tiny wrinkles on the surface of the coating.
Wavelength interval of light (between ~380-780 nm) perceived by the human eye. Orbit electrons of atoms and molecules constituting the objects, radiate when exposed to an external energy intense enough to stimulate the electrons. Only a small part of these radiations, X-ray being the strongest and radio waves being the weakest, is visible to human eye.
Determination of color, distinguishing only with human eye without using any measurement tools. One or more of the following is intended by this process: (i) Estimation of pigment or dye stuff content of an observed color with an unknown composition. (ii) Determination of matching degree of an observed color according to a reference color. (iii) Determination of types and amounts of stains to match an observed color with a reference color.
Type of polymerization that allows growth of the polymer chain on different ends as a result of a silicone structured initiator activating alternating ends of polymer chain in turns or activating ends of two separate chains in turns during growth. Monomers used in group transfer polymerization should contain carbonyl or nitrile groups. Such growing polymers are also called living polymers.
Its timber is dense and tough. Hornbeam timber is not suitable to use in construction carpentry and cabinetry. It gives best results in producing small scale but tough objects. It is used in flooring and production of wooden parts of laboratory equipment.
Top part of the ship, above storage and cabins, suitable for strolling.
Ratio of non-volatile content volume of a wet paint to the total wet paint volume is defined as “non-volatile content by volume”.
Surface layer, formed during hot rolling of steel that contains iron oxide and rolling oils in their compositions besides steel.
General name for organic coatings that can lead to dry rigid films at ambient conditions without any assistance after application. Coatings that form films by solvent evaporation and oxidative drying are characterized as “air drying”, since they appear to dry with no assistance.
Applications based on breaking and spraying the liquid paint in tiny droplets to surfaces with the help of pressurized air. Spray applications performed by air spray guns using pressurized air at 2,5-5,5 atm. are widely used especially for industrial coating applications. In air spray applications, paint is sprayed in droplets of 20-50 micron diameter.
Spraying of paint through a thin nozzle at 5-35 atm pressure. In airless spray applications, the paint can be sprayed as droplets of 70-150 micrometer diameter by means of an airless spray gun. The bouncing effect and related paint loss is less compared to air spraying applications.
General name for fats stored in animal bodies and formed by reaction of three hydroxyl groups of glycerine with animal fatty acids, especially stearic acid.
Fineness of grind gauge with the deepest edge of 100 microne depth marked as “zero” and the shallowest edge of zero depth marked as “eight”. Therefore, in Hegman gauge, each unit between zero to eight corresponds to 12,5 micron fineness.
Melting point: 35°C
Monomeric melamine formaldeyde subjected to complete etherification with methanol. Its low molecular weight and solubility in both water and organic solvents enables its usage as high solid content coating input. Because it is completely etherified, acid catalysts need to be added to the coating formulations in order to enhance the reaction tendency, which is lower compared to butylated melamine formaldehyde resins.
Diisocyanate used to produce polyurethane coatings with high flexibility and high outdoor durability. Non-volatile biuret or its trimers are used as hardeners instead of volatile HMDI for occupational health concerns.
Boiling point: 140-142°C
Polyol used in limited amounts to enhance flexibility of polyester for saturated polyester production.
Aliphatic solvent used in coatings industry.
Boiling range: 94-99°C; Evaporation number based on the ether: 3; Specific gravity: 0,715-0,725; Refractive index: 1,397; Flash point: -5°C
Tests that aim to accelerate the destructive effects of external factors compared to those under normal conditions by increasing the intensity of those factors. (e.g., accelerated setttling tendency test or accelerated corrosion test and so on).
Monomer of ester structure, used in synthesis of acrylic polymers with hydroxyl functional groups.
Cellulose derivative used as rheology modifier and thickener especially in latex based architectural coatings.
General name for subtances having tendency to adsorp and absorp water.
Vegetable oil obtained from seeds of Ricinus communis. It is used in production of oven dried or two component coatings as OH functional and monounsaturated ricinoleic acid constitutes almost 90% of the fatty acids it contains. During dehydration, castor oil loses one OH group and one H atom, thus losing one H2O from its molecule. This results in the formation of a new carbon-carbon double bond and since number of double bonds increases to two, the molecule turns into a drying oil which is called and separately used as “dehydrated castor oil
Castor oil derivatives, having tendencies to establish hydrogen bonds with the binders over their OH groups, provide the coating with a thixotropic structure. Sensitivity to high temperatures applied during paint production can be noted as their weakness.
A polymer is called a homopolymer if it grows by repetition of a single monomer (e.g., -AAAAA-, A being the monomer). Examples are polyethylene, polypropylene etc.
Birch is a dense, fine-grained and moderate tough tree. It is flexible and strong. Its sapwood and heartwood is same in color. Its use in woodturning is difficult and it has a poor exterior durability. It decays fast in outdoor exposure. It is used in engraved furnitures, musical instruments, sledges, skis, plywood production, barrel, pulley, bobbin case and wooden lasts.
Lime tree has very soft timber. Growth rings are not distinctive. It has small pore structure and its appearance is uniform. Lime tree is a dense, fine-grained and flexible tree. It considerably shrinks during drying. It decays fast in open air and changing weather conditions. Its durability against physical conditions is poor. It is an easily processable and light weight tree. Its timber is whitish yellow and reddish white. Timber of lime tree is primarily used in wood carving, statuary as well as mannequin and drawing board production.
Amount of energy required to increase the temperature of 1 gram of a pure substance by 1°C.
1) General name for reactive chemical substances that are able to harden and become insoluble by polymerization upon heat exposure; 2) General name for polymeric materials that harden and become insoluble by polymerization upon heat exposure.
General name for substances that can repeatedly soften when heated and recover to their original hardness after cooling.
Coating defect described by coating’s inability to form a film during or after application to the surface. Dewetting occurs when surface tension of wet coating is higher than that of the application surface.
General name for additives that are used to (a) perform dispersion of pigments and fillers using less energy in shorter time, (b) increase dispersion stability in the fluid composed of resin and solvent.
Spreading of a fluid on a surface as a thin homogeneous layer due to its lower surface tension than that of the application surface.
Light fastness is defined as the resistance of organic coating inputs, especially dye stuff and pigments, to destructive effects of sun light. In addition, light endurance of a dried coating film is also defined as light fastness.
One of the three components used to define a color (other two are hue
). Highest lightness corresponds to white, while lowest lightness corresponds to black. Therefore, by lightness, darkness-lightness state of a color on the black-white axis is meant.
Coatings formed by reaction of reactants with the help of radiation energy to give a rigid film. UV curable coatings and Electron beam (EB) curable coatings are the two main types of radiation curable coatings.
Storage of binders, having reactive groups that give crosslinking reactions at room temperature, in the same container leads to gelation. Containers that contain binders with reactive groups and stored in separate containers are called two-pack coatings. They are widely named as 2K coatings or 2K varnishes etc. In cases when reactive groups react in presence of a catalyst, the catalyst is stored in the second component. In some rare situations, both reactive groups and catalyst need to be stored separately.
In coatings industry, conductivity is frequently used to state the electrical conductivity of wet coating or dry coating film. 1) It is important that electrical conductivity of a solventborne wet coating is convenient for electrostatic spraying application. 2) If a dry coating film is conductive enough, it enables application of another layer of coating by electrostatic spraying or electrophoresis.
Solvent or solvent blend used to adjust the viscosity of wet coatings for a defined application.
Percentage ratio of thinner amount that has to be added to a wet coating to bring it to the required viscosity, to the amount of undiluted wet coating.
General name for surface treatment operations applied to enhance corrosion resistance of metal surface and to improve adhesion of organic coatings. Iron phosphate coatings are obtained by converting the iron atoms already present on the metal surface to iron phosphate molecules by using phosphoric acid rich compounds. On the other hand, zinc phosphate or phosphate-nickel-manganese (trication) phosphate coatings are obtained by formation of a thick crystalline layer that enables higher corrosion resistance than iron phosphate coatings.
Inorganic based pigments, most of which are formed by metal oxides, metal oxide mixtures and carbon black. Almost all inorganic pigments used today are obtained synthetically.
General name for architectural and constructional coatings that have primary function of decorating interior and exterior parts of buildings, and secondary function of protection. They are also known as decorative coatings.
Coating defect seen in brush applications described by glittery marks of thread or fiberlike appearance paralel to the brush application direction. This defect is caused by fillers with big particle sizes. In addition, similar marks can be observed in dipping applications. In this case, coating defect is caused by the surface tension differences.
Dryness level needed to stack coated pieces is called dry to stack, and time needed to reach this dryness level is called dry to stack time. In order to measure dry to stack time, coated pieces are stacked so that coated surface touch each other and is subjected to a constant pressure (e.g, 50 kg/m²) applied by a mass for 24 hours. Later on, easiness of separation from each other is observed and coated surfaces are investigated for defects such as delamination etc.
Dryness state at which coated pieces can be stacked without sticking to each other is defined as stackability. Safe dry to stack time of a coating for a certain application material is determined by “dry to stack test” at laboratory conditions.
Amount of iodine in grams required to saturate the double bonds in 100 grams of oil is called the iodine value. Iodine value is generally directly proportional to the oxidation drying capacity.
Alcohol similar to n-butanol in terms of solvent strength.
Chemical name: Isobutyl alcohol, 2-methylpropane-1-ol
Boiling point: 108°C; evaporation number relative to ether: 25, specific gravity: 0,803; refractive index: 1,3959; flash point: 27°C
Type of acetate similar to n-butyl acetate in terms of solvent properties.
Chemical name: Acetic acid isobutyl ester
Boiling point: 117,2°C; evaporation number relative to ether: 7,7, specific gravity: 0,870; refractive index: 1,3902; flash point: 18°C
Solvent having similar but weaker solvent properties to butyl acetate.
Chemical name: Isobutyric acid isobutyl ester
Boiling point: 140,7°C; evaporation number relative to ether: 21, specific gravity: 0,853; refractive index: 1,3999; flash point: 37°C
Polyisocyanate having outdoor durability as good as hexamethylene diisocyanate (HMDI), but lower flexibility than HMDI.
For polyurethane coatings, its prepolymer is used instead of IPDI due to the occupational health concerns. Monomeric IPDI, like other monomeric isocyanates, partially evaporates at room temperature and leads to health risks.
Chemical name: 5-isocyanate-1-(isocyanomethyl)-1,3,3- trimethylcyclohexane
Isophtalic acid is obtained by oxidation of m-Xylene. When used in unsaturated polyester and alkyd formulations instead of phtalic anhydride, resins are obtained with better thermal and chemical resistance and mechanical strength.
Chemical name: Benzene-1,3-dicarboxylic acid
Melting point: 347°C
Alcohol that dissolves urea and melamine formaldehyde resins, polyvinyl acetate and polyvinyl butyral, in addition to being widely used as a thinner for resins together with aromatic solvents.
Chemical name: Isopropyl alcohol, propane-2-ol
Boiling point: 82,4°C; evaporation number relative to ether: 10, specific gravity: 0,785; refractive index: 1,3772; flash point: 12°C
General name for compounds, having NCO functional groups, formed by reaction of polyisocyanate monomers with their own kind or with polyols over some of their isocyanate (NCO) groups (e.g., Toluenediisocyanate and trimethylol propane prepolymers, biurets of hexamethylenediidocyanate, isophorone diisocyanate and water prepolymers etc.).
Formation of insoluble coating films is aimed by crosslinking binders present in the coating formulation. Determination of crosslinking ratio of coating film has influence on the performance of the film after application. In order to determine this ratio, a solvent or solvent blend is chosen to dissolve the unreacted binder left in the film. Pieces of coating film, scraped from the surface, are extracted with the chosen solvent (blend) and unreacted binder is removed from the film together with the pigments and fillers attached to it. Percentage ratio of remaining sample weight to the initial sample weight is called the gel fraction.
Formation of blisters filled with gas or liquid on a dried coating film. Main reasons for liquid filled blisters could be development of local corrosions on the application surface and existence of water soluble salts in wet paint or application surface. In addition, for especially oven dried coatings, factors such as existence of solvents that are unable to pass the thick coating film can cause gas filled blisters. Blistering is a defect that hinders the protective and decorative functions of the coating.
Coating defect described by wrinkled appearance of a partially crosslinked dry film after swelling under the influence of strong solvents when a coating containing strong solvents is applied on it.
General name for additives used in oxygen-cured coatings to prevent skinning of mentioned coatings in their containers during their shelf life.
Varnishes- glossy, silky mat, mat etc- applied as a thin layer on paper surfaces to prevent from destructive effects of moisture, oil etc. and to provide an appealing look. Being mostly used for packaging papers and papers for brochures, catalogs, magazines etc., an important portion of paper coatings are produced using UV cured polymers.
Test method used to determine the surface hardness of a dry organic coating film using a pencil with standart hardness. For pencil hardness test, pencils of following standarts are used arranged in increasing hardness level: 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H. Coated surface is scratched with a pencil tip, square shaped with sand paper. A coating’s pencil hardness is defined as the hardness that is one level softer than the softest pencil leaving a permanent mark on the surface.
Material applied on the inner surfaces of molds to ease the removal of objects, especially plastics, from the mold after injection. Release agents are chosen from substances with low surface tensions in order for the molded object not to stick to the mold. Failure in removing the release agents from the coating application surfaces causes surface defects such as craters, orange peel and poor adhesion.
Material applied on the inner surfaces of molds to ease the removal of objects, especially plastics, from the mold after injection. Release agents are chosen from substances with low surface tensions in order for the molded object not to stick to the mold. Failure in removing the release agents from the coating application surfaces causes surface defects such as craters, orange peel and poor adhesion.
Calcite is the ore of lime stone (CaCO3) with rombic structure. Refractive index: 1,60; specific gravity: 2,70-2,71; oil absorption: 17±2 g/100 g calcite. Extender obtained by grinding of the ore, is widely used especially in architectural coatings.
Mineral of aluminum silicate containing crystal water is known as kaolin (Al2O3.2SiO2.2H2O). Refractive index: 1,56; specific gravity: 2,58; oil absorption: 40 g/100 g kaolin. Filler material obtained from grinding of the mineral, mainly used in paper industry and also used in exterior architectural coatings in coatings industry.
Decomposition of liquid petroleum distillation products, natural gas or acetylene to carbon and hydrogen leads to hydrogen generation and carbon black (soot) formation. Carbon black is a black pigment widely used in coating industry.
Carbon steel is alloy of iron and contains 0,05-2,00 % carbon. It has superior mechanical strength and corrosion resistance compared to pure iron. Manganese, silica and copper are also added to carbon steel in addition to iron and carbon.
Equipment used to homogenize the coating during production or before application and is composed of an engine, a mill attached perpendicularly to the engine and a mixer knife attached to the mill. Depending on the mixer knife type, propeller type, serrated type, anchor type mixers are used.
Main part of a ship that is always submerged in the sea. For this reason, outer surface of the carine is always exposed to salty water, biological accumulation, and friction when the ship is on the move or the sea is rough.
Filtration of coatings with “deep filtration method” under an applied pressure using cartridge filters having controlled porous structures. Presently, cartridge filters of 1µm to 100µm pore sizes are used for paint filtration processes.
Physicochemical process that occurs as deposition of positively charged organic polymer particles, previously suspended in aqueous medium, after migrating to cathode of the electrolytic circuit under direct current and being reduced at the cathode. See Also Cataphoretic coatings
Additives used to accelerate the crosslinking reactions in organic coating formulations. Catalysts can be directly added to the coating formulation, or they can also be packed separately and added to the formulation right before application.
Test applied to determine the water resistance of organic coatings. For cataplasm test, water-absorbed cotton is covered by a thin polymer film to avoid evaporation. Later on, mentioned piece of cotton is left on the coating film for a certain time period (e.g, 8 hours) at a certain temperature (50°C, 60°C, 70°C, 80°C, ...) and effects of water is observed (softening, lifting, color change etc.).
Amount of solvent-free binder present in 100 units of wet paint or binder solution.
Polymerization of unsaturated reactive molecules by addition over their unsaturated sections via activation by chemicals, also known as initiators. Addition polymerization is comprised of four steps: Initiation, propagation, chain transfer and termination. Addition polymerization reactions forming free radicals, organic cations or organic anions via initiators are named as follows: Free radical polymerization, Cationic polymerization, Anionic polymerization.
General name for coating formulation inputs that constitute maximum two percent of the formulation causing dramatic changes in technical properties of coatings. Additives are used to obtain required properties during production, application, storage and shelf life.
Organic coatings formed by coating of an object- having a conductive surface- connected to a circuit as the cathode by positively charged paint particles suspended in aqueous medium under direct current. Cathodic electrodeposition coatings are most widely utilized for automotive coatings. Perfect adhesion enables superior corrosion resistance. These coatings are also known as cataphoretic coatings.
A metal object, desired to be protected from corrosion, is made the cathode of an electrolytic circuit and therefore, corrosion rate is decreased dramatically. This method is called cathodic protection. Cathodic protection can be obtained by constructing a circuit with the metal to be protected and an inert electrode; and using the metal as the cathode by applying a voltage. Another method is to connect the metal object with a more active metal (called sacrificial anode) to form an electrochemical cell.
Process that causes a decrease in corrosion rate as a result of less conductive depositions on cathode surfaces.
One of the basic electrodes present in a electrochemical cell. The electrode where reduction reaction occurs is called the cathode.
Remainder of the juice of rubber tree (Hevea brusiliensis) after evaporation. Rubber, chemically composed of polyisopyrene, crosslinks with sulfur compounds forming a high resistance elastomer. Process of crosslinking with sulfur compounds is called vulcanization, and rubber that undergoes vulcanization is called vulcanized rubber.
It has white, dark white, yellowish white and brown heartwood depending on the species. Growth rings and grains are not distinctive. It has a very soft, coarse and loose structure. It sticks well with glue. It has a low physical strength. Large diameter poplar trees are commonly used in veneer and plywood industry. Poplar timber is used in match making. Furthermore, poplar is used in the production of packing boxes, barrels to keep dry stuff and chipboards.
Wood of beech tree is dense and tough. Its sapwood is reddish brown. It lasts long and is durable because of its hard structure. Fibers of beech tree can absorb varnish well. In addition to any type of solidwood work and furniture, beech tree is used in production of panels, tool handles, and musical instruments as well as in woodturning.
Boiling point is defined as the temperature that vapor pressure of a pure liquid reaches to the total outside pressure. At this temperature, the liquid boils and evaporates rapidly.
Boiling of liquids that are not pure, occurs at a boiling range rather than a single temperature. This range is called the “boiling range”.
In latex coatings, for which polymer suspensions in water are used as binders, the polymer particles approach each other to form a continuous rigid film as a result of water evaporation. In order for the coalescence to take place also at ambient temperatures, some glycol based solvent is commonly added to latex based architectural coatings.
Branch of science that investigates the changes in the rheology of a fluid, having components that undergo a chemical reaction, during the course of the reaction. It is also used to investigate the rheological behaviour of crosslinking organic coatings during the film formation process.
Self polishing coatings are mainly applied to submerged surfaces and produced using binders that undergo controlled hydrolization in sea water. Residues accumulated on the surface, leaves the surface together with the top coat binder as a result of water contact. Thus, leaving a clean and polished surface.
Separation of a substance’s neighbouring particles from each other by applying different parallel forces causing different particle velocities. (e.g., knives of scissors cut a piece of paper by applying forces in two opposite directions normal to paper surface. These forces are called shear forces. Shear force is applied to the paint formulation by mixer blade while mixing.)
Fluids that undergo a viscosity decrease upon exposure to shear force (e.g., mixing or shaking). They regain their original viscosity after removal of the shear force. Pseudoplastic fluids regaining their viscosity a while after shear force removal are called thixotropic fluids. An important portion of coatings demonstrate thixotropic behaviour.
Fluids that undergo a viscosity increase upon exposure to shear force (e.g., mixing or shaking). They regain their original viscosity after removal of the shear force. Some pigment pastes with high pigment loading demonstrate shear thickening behaviour.
Its timber is between dark yellow and white in color. It is easy to process but heavy and brittle. It has good water resistance. Growth rings are distinctive and uniform. They are used in veneer, solidwood furniture production and interior decoration. It is suitable for producing long-lasting and durable furnitures. Paint and varnish can be applied on it.
Special corrosion test performed to estimate the resistance of coatings to corrosive effects of sulfur dioxide from chimney waste.
Organic chemical compounds containing a carbonyl group (C=O) and having a general formula given below.
Paint especially designed and produced to give a wrinkled appearance. Wrinkled paints are designed so that the upper surface of the wet paint dries faster than the overall film.
Coating defect described by the wrinkled appearance caused by faster drying of surface layer of a wet coating film than lower layers, similar to lifting defect.
Refractive index of a substance is the ratio of speed of light in space to speed of light in that substance. It is also defined as the ratio of sinus of the angle between the light coming from space hitting the object surface and normal, to the sinus of the angle between refracted light and normal.
Name of the harder, darker and denser rings that are present in the cross-section of a tree and that are formed during winter time.
It‘s named as red pine because of its reddish buds. Red pine is a resinous tree. Since its trunk is curved and branched, red pine tree is used in production of packing boxes as well as in rough construction works.
Resistance of organic coating films to possible effects of chemical substances that they are exposed to throughout their service lives. For industrial coatings various acid resistances, alkaline resistances, fuel and solvent resistances; and for domestic coatings alcohol, ketchup, oil, sweat, tomato paste resistances can be mentioned among chemical resistances.
State of dryness and hardness needed for a coating film to reach the expected chemical resistance is called chemical drying, and time period needed to achieve chemical drying is called chemical drying time. Chemical drying time is determined by measuring the chemical resistance of the coating film.
Its durable and reddish wood with uniform grains is used in interior decoration as solidwood or plywood in addition to making high quality furniture. Works that require lathing, embossing and engraving on wood, modeling and production of musical and scientific instruments. In producing high quality articles, its sapwood is used. Paint and varnish can applied on cherry well.
Hard thermoplastic resin that is obtained from reaction of natural rubber with chloride, containing approximately 65% chloride and that is soluble in aromatic solvents. It has superior chemical resistance and water resistance. There are also some commercial products obtained from chlorination of synthetic rubber.
Hardness measured by marking the coating film using a diamond tip that carries a certain weight. Knoop hardness is calculated by dividing the mass, that applies the weight, by the area of the mark observed on the surface.
Attraction of molecules of same kind towards each other resulting in stable agglomerates of those molecules both in liquid and solid phases is called cohesion. Attraction forces that similar molecules apply to each other leading to cohesion are called cohesion forces.
Functional groups on a molecule can have positive or negative effects on the tendency of the neighbouring groups of the same molecule to react with other compounds. This effect is called “neighbouring effect”.
Term used to describe the position of double bonds in a molecule with respect to each other in the case that double bonds are separated from each other by one single bond. See Also Conjugated fatty acids
Fatty acids containing double bonds separated from each other by one single bond on their main molecule chain that is composed of carbon-carbon bonds. e.g., eleostearic acid, licanic acid etc.
Oils containing mainly conjugated fatty acids in their structures.
During obtaining of wooden materials, if the cutting direction is perpendicular to the grain direction of wood, it is called end cutting. See Also Edge Cutting
Pigment particles undergo controlled flocculation with the help of dispersion additives that hold on to the pigment particles over their pigment-loving groups. Bigger particle sizes are obtained compared to deflocculation; however, “hard precipitation” tendency of the coating decreases. Controlled flocculation is a widely used technique during dispersion of primer pigments and fillers.
End cut and edge cut thin wood panels of the same number with 1 mm thickness are glued and pressed together such that adjacent plies have different wood grain at right angles to each other. Wood panels obtained by this technique are called plywood.
Application of paints and varnishes by spraying in tiny droplets using air guns with air at 2,5-5,5 atm pressure. Feeding of coating to the gun is achieved either by gravitational forces from a cup placed on top of the gun, or by suction from a cup placed under the gun or by pressurizing the paint.
Heating ovens that contain hot combustion gases or heated air inside. The hot combustion gases or air provides drying and curing of the objects coated with oven-cured coatings.
Polymers having more than one type of repetitive units such as –ABABAB– or –AAABBBAAA–, where A and B are two separate units. (e.g., ethylene vinyl acetate copolymer)
Electrostatic coating method used to coat a positively charged surface with little loss, using powder coating particles charged by air molecules ionized under high voltage.
Electrochemical circuit that has two different metals as its electrodes and that more active electrode naturally behaves as the anode, experiencing corrosion.
Laboratory tests that aim to determine the corrosion resistances of coated or uncoated materials in a much shorter time than actual exposure periods in their usual service lives, by subjecting the materials to severely corrosive conditions.
Coarse wood with no grains. Timber of fir-silver fir is yellowish white and matt. Owing to distinctive growth rings with no color difference, it is also used as veneer.
Additives that accumulate on the surfaces of microbubbles in the wet coating and enables combination of microbubbles to grow into bigger bubbles that migrate to the paint surface and leave the system.(e.g., polyethers with limited compatibility, polyacrylates, polymethylalkylsiloxanes)
Foam stability is defined as the resistance of bubbles, caused by air trapped in the wet coating during production or application, against bursting and disappearing. It is known that silicon additives increase the foam stability if they are highly compatible with the coating and they effectively decrease the surface tension.
Bubbles in the wet coating cannot burst easily even if they are moved to the surface by defoamers. For this reason, it may be necessary to use bubble breakers to ensure bursting of the bubbles on the surface. (e.g., mineral oils, dimethylpolysiloxanes with limited compatibility)
Cup shaped cavities, that remind volcano craters and that are caused by local surface tension decreases, are called craters. Gel particles, oils, foreign materials, fibers, incompatible silicon contamination and spray dusts of other coatings can be counted among the typical crater causes.
Pigment volume concentration at which all the binder in a coating formulation is used up to wet the pigments and to fill up the pigment pores, leaving no free binder.
Color parameters obtained by converting measured X, Y and Z values of any color to decimal numbers that sum up to 1. This way, instead of three parameters, an easier two-dimensional color coordinate system is obtained.
Accelerated outdoor durability test that aims to simulate the accelerated effects of sun light using xenon lamps.
Solvent obtained from high aromatic content petroleum and coal tar. The solvent, that is known by the name xylene in coating industry, is in fact a blend of three isomers having the chemical formula
Some properties of xylene blend used in the coating industry are as follows:
Boiling range: 137-143°C; evaporation number relative to ether: 13; specific gravity: 0,871; refractive index: 1,4980; flash point: 25°C
Surface preparation treatment performed to remove dirt, oil, rust etc. from application surfaces (metal, concrete etc), and to increase surface roughness for improved adhesion. For sand blasting process, high silica sand, hard metalic abrasives; for more sensitive surfaces (e.g., plane bodies) hazelnut shells, plastic granules etc. are sprayed to the surface via pressurized air. Regarding sand blasting, SSPC (Steel Structures Painting Counsel) standards are widely used in industry.
Mills that aim to grind pigment aggregates using high silica sand as the grinder. See Also Bead mill
Valuable metal objects, which need to be protected, are connected to electrochemically more active metals or alloys to construct a corrosion circuit. In that case, the active metal behaves as the anode and is depleted by corrosion at a certain rate. Meanwhile, the other metal is protected from corrosion. The material connected to the circuit to behave as the anode is called the sacrificial anode.
Thickness of a coating after application and formation of a dry and rigid film. Dry film thickness can be measured either by destructive or nondestructive methods.
Grieves’ “drying index” is widely accepted to define drying oils:
Drying index=(Percentage of fatty acids with 2 double bonds)+2*(Percentage of fatty acids with 3 double bonds)
Oils having a drying index greater than 70 are classified as drying oils. Grieves’ formula cannot be applied to oils containing conjugate unsaturated fatty acids. “Iodine value
” is also utilized to identify drying tendency.
Time period required to reach the desired drying level after application, is defined as the drying time. Depending on the drying level, various drying times can be mentioned such as dust-free drying time, dry-to-touch time, dry-to-assembly time, dry-to-stack time and chemical drying time etc.
Alkyd resins that contain saturated fatty acids on their backbone. Since non-drying alkyd resins do not polymerize oxidatively via oxygen of air, they are used in oven-cured coatings that crosslink with amino resins and in two-pack coatings that cures via isocyanate based hardeners.
General name for oils obtained by reaction of glycerine with fatty acids that do not contain unsaturation or contain limited unsaturation. There is no distinct definition of non-drying oils as in the case of drying oils. However, oils with an average unsaturation value smaller than or equal to one double bond per one fatty acid chain, are practically classified as “non-drying oils”.
General name given to organic coating additives that catalyzes the oxidative drying process. Almost all commercial driers are metal soaps that can dissolve in coating solvents. Among main driers are soaps formed by reaction of metals such as cobalt, manganese, lead, zinc, zirconium, calcium etc. with octoic acid and naphtanic acid.
Alkyd resins, that contain two or more unsaturated fatty acids on their backbone, tend to form films that harden by air oxygen. Alkyd resins, containing fatty acids with average drying index of 70 or higher, are classified as drying alkyd resins.
Natural vegetable oils that contain unsaturated fatty acids connected to three hydroxyl group of glycerine molecule. Drying oils dry by polymerizing with air oxygen via opening of the double bonds on fatty acids.
Solvent added in small amounts to organic coating formulations as the last solvent to leave the coating film due to being less volatile compared to other solvents in the formulation.
Ash content is determined by heating the organic coating material up to the temperature at which its binder decomposes or burns. For this purpose, a 2 gr sample is heated at 800°C for 5-6 hours, and ash content is calculated as the percentage ratio of residual ash amount to the original sample amount.
Process of transformation of an organic coating film to a rigid film of thermosetting character as a result of polymerization reactions.
A round shaped dent on dry paint film. A hole, formed by gas or solvent vapor trapped in the coating film while leaving the film, can grow into a larger semi-spherical concavity as a result of partial levelling of the film. This surface defect is called “cuvette”. This defect is mainly encountered in oven-cured coatings containing trapped air or solvent vapor, and polyurethane coating films with trapped carbon dioxide in them.
Its timber is flexible and tough with a high humidity resistance. Spruce is frequently used in all types of construction works, outdoor and indoor woodworks, flooring and in staircases. Since, spruce can be polished it is used in making of furnitures. Furthermore, spruce is used for production of plywood, matches, paper and rayon.
General name of pigmented top coats given by paint appliers in Turkish furniture sector
General name of very durable and elastic organic polymers. Natural rubber is the most frequently used type of rubber. Natural and synthetic rubbers are cross-linked through vulcanization so that their strength, elasticity and chemical resistance will improve. Rubbers, especially the vulcanized rubbers are also called as elastomers.
Binders produced by stable dispersion of solid polymer particles, primarily, natural and synthetic rubber in water.
Paints produced using latex binders which are aqueous emulsions of solid polymer particles.
BaSO4.ZnS. Mixed Crystal; refractive index: 1,84; specific gravity: ~ 4,3; oil absorption value: 11-17 g/100 g lithopone. Lithopone is a white extender with poor hiding power and it is produced by co-precipitation upon mixing of barium sulfate and zinc sulfide.
Organic coating material that contains extenders above the Critical Pigment Volume Concentration (CPVC
). Putties are used to fill holes, cracks, and eliminate roughness on the substrate. Putties can be applied using spatula and rollers due to their high viscosity.
When a closed half-filled bottle of wine, turned upside-down after shaking, it is seen that the wine in the bottle starts to climb the walls of bottle. Since, Italian physicist Carlo Marangoni explained the physicochemical mechanism lying under this phenomenon at the beginning of 1990’s, it’s called Marangoni effect. Alcohol in the thin wet film on the lateral surface of partially full bottle of wine evaporates more rapidly than water. Hence, alcohol amount decreases in these parts, resulting in increase in water concentration. The surface tension of pure water is higher than that of pure ethanol. Therefore, the surface tension of the liquid film from which alcohol evaporated increases. Then, a flow gradient occurs from the bulk part of wine which has lower surface tension, to the thin film layer on the sides with higher surface tension.
Wooden material obtained by giving a shape to timber cut from log or by joining different timbers. The difference of solid wood from MDF
, particle board
is its natural wood structure.
General name of putty based elastic organic coating materials containing high level of extender. They elastically fill the junction points or the whole surface of objects, to impart protection against water and chemicals as well as heat and sound isolation.
Mattness, which is the reflection of incident light in a broad range of angles, can be imparted using some additives. These additives are mainly micronized silicon particles and various types of polymer waxes
If the incoming light (incident light) on a substrate is reflected in a broad range of directions instead of a single outgoing direction, mattness occurs. Paints and clear coats are classified according to the mattness they have as silk, semi matt or satin, matt or flat and eggshell. However, there is no common opinion in the paint industry on the gloss levels corresponding to these mattness classes. A common misperception is that matt surfaces reflect less light. A matt surface reflects light as much as a gloss surface does. The difference is, light reflected from matt surfaces comes to the eye in a whole range of angles, whereas, light from glossy surfaces comes making the same angle of incident light with respect to the surface normal. Reflected light form a surface depends on the color not the gloss of the surface.
Its timber is free of voids and not flexible. It has excellent workability. Paint and varnish can be applied on it well. It shows a great durability against changing weather conditions. Pieces made out of it are connected It sticks with nail, screw and adhesive. It dries well. It is suitable for engraving and lathing.
Symmetrical triazine compound synthesized by heating up urea in the presence of ammonia. It is primarily used in the production of melamine formaldehyde resins.
Chemical Name: 1,35,-Triamino-s-2,4,6-triazine
Melting Point: 354°C
Polymerization products of melamine and formaldehyde. They are the most common cross linkers in baking systems. Melamine formaldehyde resins are modified with various alcohols to increase solubility in paint solvents and compatibility with polymers.
Its timber has dense structure with thick, short and flexible fibers. Tannin content prevents the oak tree from decaying. White and black oak is used in construction works. Timber of oak tree is hard and heavy with high humidity resistance. Due to its high price it is used only in critical places where strong abrasion resistance is required. It is used in furniture making as veneer or solid wood. Furthermore, oak tree is favorably used in water bridges, bridge piers, vessels, barrels, pier piles, traverse and vertical members in mines.
An acidic monomer commonly used in the synthesis of acrylic polymers.
Melting point: 14°C; Boiling point: 163°C
Organic coating applied on inside and outside surface of a can is called “can coating”. Can coatings are used to form an isolated layer between packaged goods and packaging material, as well as prevent rust formation on the outside surface of packaging materials and enhance aesthetics.
Marks left on a painted film when bare metal is drawn across its surface. Especially, white and light-colored surfaces are more susceptible to metal marking. This paint defect can be prevented to a large extent by using slip additives, extenders like platelet kaolin or a sutiable resin.
General name of paints, having glossy surfaces as newly sandblasted because of the aluminium pigment flakes in their composition.
Wearing away of metals due to electrochemical reactions is known as metallic corrosion. Oxidizing of metals through an electrochemical process leads to the formation of metal oxides or other metal salts. Of these corrosion products, metal oxides are commonly named ”rust”.
Due to the lack of good solvency in most organic polymers, its use in paint industry is rare.
Chemical name: Methyl alcohol
Boiling point: 64,7°C; Evaporation number based on the ether: 6,3; Specific gravity: 0,792; Refractive index: 1,3287; Flash point: 11°C
It is a ketone analogous to acetone having similar solvency but volatile.
Chemical name: butan-2-one (abbreviated as MEK).
Boiling point: 79,6°C; Evaporation number based on the ether: 2,6; Specific gravity: 0,805; Refractive index: 1,3788; Flash point: -1°C
Glycol ether that dissolves cellulose derivatives, epoxy resins and polyvinyl acetate. Due to the potential risks to human health, its use is restricted.
Chemical name: Ethylene glycol monomethyl ether; 2-Methoxyethanol (also known as methyl cellosolve)
Boiling point: 124,5°C; Evaporation number based on the ether: 34; Specific gravity: 0,964; Refractive index: 1,4021; Flash point: 37°C
Ether acetate used in similar areas as methyl glycol. Due to the potential risks to human health, its use is restricted.
Chemical name: Ethylene glycol monomethyl ether acetate; 2-Methoxyethyl Acetate (also known as methyl cellosolve acetate)
Boiling point: 145°C; Evaporation number based on the ether: 35; Specific gravity: 1,005; Refractive index: 1,4019; Flash point: 47°C
It is a ketone having less solvency effect on polymers that acetone can dissolve.
Chemical name:4-Methylpentan-2-one (abbreviated as MIBK).
Boiling point: 117°C; Evaporation number based on the ether: 7,0; Specific gravity: 0,801; Refractive index: 1,3958; Flash point: 14°C
Ester based monomer of polymethylmethacrylate in addition to its use in synthesis of various acrylic copolymers.
Boiling point: 100,5°C
Ketone used as an additive in paint formulations.
Chemical name: 1-methyl-2-pyrrolidone
Boiling point: 202°C; Evaporation number based on the ether: 360; Specific gravity: 1,028; Refractive index: 1,4680; Flash point: 91°C
Glycol ether having same solvency as ethylene glycol.
Chemical name: propylene glycol monomethyl ether
Boiling point: 121°C; Evaporation number based on the ether: 25; Specific gravity: 0,922; Refractive index; 1,4040; Flash point: 30°C
Glycol ether acetate that dissolves cellulose derivatives, polyvinyl alcohol, polyester and short oil alkyd resins. In addition, it is used as co-solvent in waterborne organic coatings.
Chemical name: propylene glycol monomethyl ether acetate
Boiling point: 146°C; Evaporation number based on the ether: 33; Specific gravity: 0,966; Refractive index: 1,4020; Flash point: 45°C
A mineral found in muscovite rocks. It’s primarily composed of aluminum potassium silicate (Al3KSi3H2O12). Mica will appear in light brown and in platelet form. Refractive index:1,58-1,61; Specific gravity: ~2,80; oil absorption value: ~65 g/100 g mica. Its use in paint industry is rare.
A test method at which an instrument records the motion of a sharp indenter impressed into the paint film at slightly increasing loads. Carrying out this test, makes it possible not only the measurement micro-indentation hardness of the coating but also the determination of the elastic and plastic deformation thresholds of the paint film.
A unit of length equal to one thousandth of a millimeter.
Monochromatic light is a light ray of a single wavelength. It is produced either by radiation caused by heating up some pure metals or by passing the polychromatic light through prisms (Monochromators).
The state in paint curing at which the paint film on the item will resist deformation due to the effects from firmly grasping, handling, raising and pushing etc. Since, different parameters are taken into account in the assembly of painted items; specific test methods are often preferred instead of standard methods.
General name of additives used to prevent degradation of organic coating films exposed to UV light. UV stabilizers are classified into two groups. UV stabilizers (also called as UV absorbers). They convert the absorbed UV energy into heat and this heat is then dissipated through the substrate. Benzophenones and benzotriazole derivatives are commonly used UV stabilizers. The other group is free radical scavengers. They act by trapping the free radicals formed by UV light and decompose these radicals along with themselves hereby suppress the degradation of coating. Hindered amine light stabilizers (HALS) are used as free radical scavengers.
A vehicle with at least four wheels whose propulsion is provided by an engine and used for transport of passengers as well as for carriage of goods on highways is a motor vehicle. According to the International Organization of Motor Vehicle Manufacturers (OICA), motor vehicles are classified as follows.
Distinction between light commercial vehicles and other commercial vehicles is drawn according to their transport capacity. Changing from country to country this distinction is in between 3,5 tons and 7,0 tons. In Turkey, vehicles having a transport capacity below 3,5 tons are defined as light commercial vehicle.
General name of low molecular weight polymeric materials that are solid at room temperature and can soften at nearly 50-100°C. Waxes are traditionally produced from animals (e.g., Beeswax, Spermaceti), plants (e.g., Carnauba wax, from the leaves of the Carnauba palm) and petroleum products (e.g., Paraffin wax). Waxes are chemically synthesized by polymerization of ester, alcohol and carboxylic acid or their mixtures. Other than natural waxes there are specific purpose synthetic waxes. Some of these waxes are used as additives in paint. See Also Synthetic waxes
Visual color definition system based on ten principal hues as Blue, Blue-Green, Green, Green-Yellow, Yellow, Yellow-Red, Red, Red-Purple, Purple, Purple-Blue. Each of these principal hues can be diluted with clear-coats to decrease its chroma or mixed with black pigmented paint to decrease its lightness. For instance, for a color specified as GY5/6 in Munsell color system, one can say Green-Yellow (GY), 50% mixed with black and 60% saturated. Munsell color system is commonly used in the USA. On the other hand, in Europe, Natural Color System (NCS) is preferred. NCS, ables a more detailed definition of color than Munsell system. See Also Natural color system
, Color identification systems
Generic name given to the polyamides. Different types of Nylon are the most widely used polymers in the world.
Resistance of cured paint film against degradation caused by humidity. Humidity resistance of painted film is measured in closed cabinets where temperature and relative humidity is kept constant. The change in gloss, hardness, adhesion and appereance of the film is observed after keeping it inside the cabinet for a certain time. See Also Condensing humidity test
, Non-condensing humidity test
Resins with isocyanate functionality react with moisture in the air to form polyurea. The coatings produced form these resins are called “moisture curing coatings”. Epoxy-ketimine based 2K coatings are also called moisture curing coatings because amine produced from the reaction of ketimine with water, forms a cross-linked network.
Despite the fact that, polyurea is formed from the reaction of isocyanate with moisture in the air, coatings composed of polyurea is commonly misnamed as “moisture curing polyurethane coatings”.
Polyol synthesized by the reaction of isobutyraldehyde with formaldehyde. It is a raw material for polyester resins.
Chemical name: 2,2-dimethyl-1,3-propanediol
Melting point: 128°C
Fluids having viscosity independent of shear stress. Since these types of fluids behave according to Newton's model, they are called “Newtonian fluids”.
Viscosity of some fluids may change according to the shear stress applied. These types of fluids are called “Non-newtonian fluids”. Non-newtonian fluids exhibit shear- thinning (Pseudoplastic), shear-thickening (Dilatant) or plastic flow behaviours.
See Also Shear thinning fluids
, Shear thickening fluids
General name of resins, synthesized by the reaction of phenolic compounds with formaldehyde with a phenol/formaldehyde ratio of substantially larger than 1. Therefore, Novolac resins have functional OH end groups.
To diffuse through a substance by overcoming its resistance.
Drying oils, drying and semi-drying alkyds polymerize over the unsaturated bonds in the fatty acids with the oxygen in the air. If the drying of the organic coating films occurs through this mechanism, this process is called “oxidative drying”, “auto-oxidative drying” or “drying with oxygen in the air”.
See Also Air drying
, Drying oils
, Drying alkyd resins
, Semi-drying alkyd resins
Cylic ether groups pendant to the epoxy resin. Oxirane groups are also called as epoxy group.
General name of chemicals, which are formed by the reaction of a definite number of monomers but not large enough to be qualified as a polymer. Although, there is no widespread agreement on the definition of oligomer, the molecular weight of an oligomer ranges from a few hundred to a few thousand and an oligomer consists of 2 to 20 repeating units (mers).
A property of matter that prevents light from passing through it or a condition of being non-transparent. If an object consumes all the light coming to it by reflection, scattering, and/or absorbtion, this object is said to be opaque.
1) General name of coating materials, having a backbone structure of organic polymers, oligomers or monomer based binders. Organic coating material with no pigment is called clear coat or varnish and if pigmented then it’s called paint.
2) Film formed by the film formation of organic coating material. See Also Putty
, Powder coatings
Group of pigments synthesized from basic organic molecules and possessing the ability to enhance the aesthetics in paint industry by virtue of their wide range of colors.
Natural clays with surplus OH groups on their surface, are reacted with ammonium salts to increase their compatibility with paints. They attribute shear thinning and thixotropy to the paint by forming hydrogen bonds.
Compounds having silane groups with high affinity to polar groups at one end and hydrocarbon part that is highly compatible with the main binder at the other end. Especially, they are used as additives to improve the adhesion of coatings applied on surfaces rich in polar groups like metal, glass and concrete.
Mixture of distillation products composed predominantly of aromatics. Chemical structure: No definite chemical structure.
Boiling range: ~180-210°C; Evaporation number based on the ether: 115 (for Solvesso 150), 148 (for Shelsol AB); Specific gravity: 0,894-0,895; Refractive index: 1,512; Flash point: 62°C
It is a panel shaped product formed by breaking down of wood chips into fibres under steam, adding urea formaldehyde and a little amount of paraffin wax, and drying under high temperature and pressure. MDF has a typical density of 600-800 kg/m³. Since the chips in MDF are broken down as wood fibres, mechanical strength and humidity resistance of MDF is higher than fiberboards like chipboard. MDF is used in production of kitchen and bathroom cabinets, drawers, shelves, bookcase and office furniture as well as for interior decoration.
Putties, primers and top coats used for painting partly or in full if an accident happens or a scratch occurs on the car in the assembly line. Plastic parts, seats made of fibers and polymeric foams and other non heat resistant accessories, do not allow the exposure of the car to temperature above 80°C. Therefore, car repair paints should be dried and cured below 80°C. On the other hand, to eliminate color and gloss differences between the painted part and the whole car, during the assembly line and throughout the service-life of the car, the resin and pigments used in repair paint should have similar durability as the OEM coating.
Vast majority of automotive components used at manufacturing plants where the main purpose is to produce cars in rapid assembly lines, are produced at various automotive component plants. Putties, primers, top coats and clear coats used for painting metal or plastic parts like engines, radiators, filters, seats, mirrors, bumpers, interior plastic parts, rims, hubcaps etc. are called automotive component coatings. In addition to paints applied to original vehicle components, paints applied to spare parts especially during the service-life of vehicle are also considered as automotive component coatings.
Paints applied to automotive products in OEMs' paintshops for bringing protection and visual attraction to cars. Nowadays, coating system of a passenger car is composed of following layers with their functions given in parenthesis.
1) Cathodic Electro Deposition (CED
) primer applied by dipping (to provide high corrosion resistance).
2) Primer surfacer applied by spraying (to increase stone chip resistance and to smooth the surface for topcoating).
3) Top coat layers applied by spraying (to increase exterior durability of coating system and to bring an appearance with glossy and attractive colors that last for long periods).
Think of two fluids with the same chemical composition but differing in concentration which are separated by a semi-permeable membrane. This membrane permits passage of small size solvent molecules but not the large solute molecules. Movement of solvent molecules from an area of low solute concentration to an area of high solute concentration is called “osmosis”. During osmosis, movement of solvent molecules leads to an increase in mass followed by an increase in pressure. The equilibrium in osmosis is reached when concentration difference (driving force of osmosis) and pressure difference which acts against it balance each other.
During osmosis in a cup divided into two parts by a semi-permeable membrane, liquid mass in the high solvent concentration part increases and exerts a pressure on the membrane. When this pressure is high enough and doesn’t allow any further mass transfer, the movement of solvent molecules stops. This pressure is called osmotic pressure. Paint film acts as a semi-permeable membrane and lets water migrate through itself when a water-soluble impurity exists on the substrate or in its composition. Osmotic pressure in paint films results in a paint defect called “blistering
Ability of any pigmented organic coating to hide or obscure the surface of the substrate. Hiding power is assessed by applying successively increased thickness of paint over a black/white contrast strips or checkerboard squares until the color difference in the background contrast could be no longer noted. The dry film thickness at this point refers to hiding power and it is defined in micrometers. Hiding power directly changes with the opacity of the applied coating film. See Also Opacity
A polymer consists of 10 to 100 formaldehyde units. Not only the hazardous effects to human health and environment but also the difficulties in processing and storing of formaldehyde gas leads to paraformaldehyde use in formaldehyde resins. Paraformaldehyde decomposes into the formaldehyde at nearly 150°C.
Varnish applied on indoor parquet floors to increase their durability against water, household chemicals and most importantly against abrasion, while enhancing their appearance.
A term defining the degree to which the gloss of an organic coating is retained after a period of service-life. Generally gloss retention is used for high gloss topcoats and it is the ratio in percentage of original surface gloss to the gloss after a service-life.
The temperature at which a solvent, solvent mixture or solvent borne paint is heated so that it ignites with a spark. Flash point test performed by introducing spark to a heated solvent contained in an open cup is called “open cup flash point test”, whereas if spark is introduced to solvent in a closed cup is called “closed cup flash point test”.
Water insoluble metal oxides formed by oxidation of metals due to corrosion.
Viscous dispersions of abrasives in liquid phase that are used to eliminate defects and scratches or chalking, which occur over time on the glossy paints or clearcoats. Pastes are used in the first stage of polishing to smooth the rough surface.
To diffuse through a substance by overcoming its resistance.
Polyol prepared by polymerization of acetaldehyde and formaldehyde in a basic environment. It is used as a raw material for the preparation of alkyd and polyester resins.
Chemical name: tetramethylolmethane, 2,2-Bis(hydroxymethyl)-1,3-Propanediol
Melting point: 262°C
A coating technique in which paint continuously falls through a slit, onto panels transported on a conveyer belt. This method is used especially in rapid lines for manufacturing sheet shaped furniture components and mirror coating lines.
Vertical rupture of dynamically discharging paint curtain due to air bubbles or impurities present in wet paint. Curtain rupture causes defects as non- painted regions on the object to be coated.
Additives that absorb and destroy free radicals, which occur due to UV light and can degrade paint film. HALS decompose themselves as they destroy the free radicals. Using HALS will greatly improves the exterior durability of paint. See Also UV stabilizers
Destructive measuring device used to determine the thickness of paint film by incising a V-groove through the film and observing the thickness with a microscope bearing a measuring scale.
Pigments are finely ground, organic solvent and water insoluble chemical substances that impart color, various visual effects and in some cases corrosion resistance to paint. Two main differences between pigments and dyestuffs are pigments are insoluble in both organic solvents and water and pigments have better exterior durability than dyestuffs.
The percentage ratio of the volume of total pigment (and extender) to the volume of total nonvolatile material present in paint formulation.
Chemical groups present in dispersion additives to ease the attachment to the surfaces of polar pigments. Pigment affinic groups comprise carboxylic acid, amine, isocyanate and their derivatives.
Paint semi-product which has a higher pigment content and generally a higher viscosity then the finished paint.
Although pigments and extenders are produced as primary particles, they form aggregates and agglomerates when they are in touch with each other in bulk phase. In dispersion stage, these pigment clusters are tried to break down to primary particles. If dispersed pigments are not stable, they form loosely combined units called flocculates. Since, the distinction between these three terms might not be clear, for a better understanding a schematic representation is given below.
See Also Aggregate
Breaking down of pigment flocculates which are combined as agglomerates or aggregates, in a binder and solvent medium. Dispersion of pigments and extenders is performed using high-speed dispersers and wet mills.
The ratio by weight of pigment content to solid binder content in paint formulation. See Also Solid binder content
Solvent vapour and other gas bubbles present in wet paint film, tend to make holes while leaving the film during drying process. Drying results in an increase in viscosity, in turn, makes it impossible for paint film to level this holes out and a paint defect called pinholing defect will occur.
When the film thickness of applied paint increases, release of solvent vapour and other gases will be retarded. Since paint film starts to get hardened during this period, the holes formed by solvent vapours and other gases become permanent if the thickness of the film is above a certain limit. The dry film thickness of paint film at which this defect starts to occur is called pinholing limit.
Plasticizers are used as softening additive in paints based on resins like cellulose nitrate. These resins have large molecules, are hard and mostly brittle.
Deposition of solid or gas phase insulation materials on an anode or cathode in an electrochemical cell hinders the current generation. This phenomenon is called electrode polarization. If the electrochemical cell is a corrosion battery, polarization increases corrosion rate.
Surface additives that prevent defects by forming a thin continuous layer on the surface. These additives are designed with limited compatibility with the paint binders and solvents so that they can migrate to the surface. See Also Surface additives
General name of alcohols having more than one hydroxyl groups. They are also known as polyalcohol or polyhydric alcohol.
Amide functional macromolecules formed by controlled polyaddition of polamides with various compounds especially epoxy resins. Polyamide adducts, due to their higher glass-transiton temperature (Tg) than polyamides, provide a partial physical drying ability for epoxy resins which in turn leads to an increase in cure rate.
Hardener for epoxy resins, composed of aliphatic polyamide resins which can crosslink with oxirane groups of epoxy resins using the active hydrogens it possesses.
An amine and amide functional hardener for epoxy resins which can crosslink with oxirane groups of epoxy resins using the active hydrogens it possesses.
General name of acids having more than one reactive hydrogen atoms in their structure. They are known as polybasic acids as well.
Hard thermoplastic polyester resin synthesized by polymerization of 1,4-Butanediol and pure terephthalic acid according to process which became wide spread in the last decade. Formerly, it was synthesized using dimethyl terephthalate instead of terephthalic acid.
The ratio of weight average molecular weight to number average molecular weight of a polymer is defined as polidispersity or polidispersity index.
Thermoplastic polyester resin synthesized by condensation polymerization of terephthalic acid or terephthalic acid dimethyl ester with ethylene glycol.
Thermoplastic organic polymers with carbonate group as a repeating unit. Generally, they are produced by reacting bisphenol A with organic carbonate (diphenyl carbonate) or phosgene gas. Carbonate group is given below.
Formerly, polychromatic light was defined as visible light array composed of many light rays in various colors. With the semantic extension in the course of time, this definition has changed to define light composed of light rays with many different wavelengths irrespective of whether it is in visible region or not.
A large molecule composed of numerous number of repeating structural units called monomers typically connected by covalent chemical bonds.
Dispersion additives having a branched/chained backbone which is compatible with paint resins and solvents in addition to having pigment affinic groups. Owing to their large molecules, polymeric dispersing additives form a layer around the pigment molecule they attach to so that other pigments are prevented from coming close. Therefore, they provide dispersion stabilization by steric hindrance.
Polymeric thickeners are polymeric in nature and impart shear-thickening to the paint. They prevent pigment settling and sagging by forming a network in wet paint by entangling themselves with polymer branches of the resin. Since polymeric thickeners contain oxygen and nitrogen atoms, they impart thixotropy to paint by forming hydrogen bonds.
General name of thermoplastic polymers synthesized by polymerization of propylene. In paint industry, polypropylene is encountered as a substrate material since its impact resistance is high. On the other hand, low surface tension of propylene (30,1 mN/m) makes the substrate difficult for wetting and adhesion of paint.
General name of surface additives that prevent surface defects like craters, orange peel, telegraphing etc. by virtue of their compatibility with paint ingredients as well as lower surface tension they have than other paint ingredients. See Also Surface additives
It is a transparent thermoplastic polymer. It can easily be made to take on various colors and it can be processed easily. Although it is brittle, its mechanical and thermal properties are suitable for production of everyday goods such as packaging, household items, home decoration as in film or foam.
Poly(tetrafluoroethylene) is synthesized by free radical polymerization of tetrafluoroethylene under high pressure and aqueous medium. It is a highly crystalline, linear and orientable polymer. Solvent and corrosion resistance is high but surface tension and friction coefficient are low. It has by far the lowest dielectric constant for all known polymeric materials. It is used in non-stick paints for painting kitchen items, hygienic bathroom and toilets.
It is a plastic material having a melting point of 170ºC and a 50% crystalline structure. It is durable against shape deformation and creep at high and low temperatures. PVDF, is used in production of coil coating topcoats with high exterior durability.
Ester based polymers derived from polycondensation of polyols and polyacids. Although their backbone structure is similar, to point out the difference from the fatty acid containing alkyd resins, they are called oil-free polyesters. If the polyols and polyacids contain unsaturation, polyester resins are called “unsaturated polyester resins”, if not, they are called “saturated polyester resins”
This surface defect can be characterized by bumps and valleys resembling an orange skin texture of substrate.This orange skin texture is generally due to poor levelling and it is more common in spray and roller applications. If the surface tension differs at various points on the surface, the migration of paint can cause orange peel. It should be borne in mind that, high viscosity is another factor hindering the levelling.
Mixture of polypropylene with rubber which is also a polymerization product of ethylene, propylene and diene monomers. See Also Ethylene propylenediene
Solvent, which dissolves natural resins, phenol formaldehyde and urea-formaldehyde resins. Mixtures with aromatic solvents provide a broad solvency range. Chemical name: n-propyl alcohol
Boiling point: 97,2°C; Evaporation number based on the ether: 16; Specific gravity: 0,804; Refractive index: 1,4680; Flash point: 23°C
On the high gloss paint surfaces, the incident light coming from an angle of 20º reflects mostly at 20º and a small part of the light scatters around 20º. This defect is perceived by the eye as haze on the paint surface.
Small diameter hole in paint spray guns through which the paint leaves the gun with an increased speed.
Paints produced using PVC plastisol resins. PVC plastisol resins are prepared by dissolving plasticizers like dibutyl phthalate or benzylbutylphthalate in thermoplastic PVC resin. PVC plastisol based coatings have remarkable properties like water and chemical resistance in addition to corrosion resistance when they are applied as topcoat of 100-200 mikrometer thickness in metal coating industry.
Coatings formed by reaction of reactants with the help of radiation energy to give a rigid film. UV curable coatings and Electron beam (EB) curable coatings are the main two type of radiation curable coatings.
Chemicals that dissolve organic coating binder and participate in the cross-linking reaction because of the functional groups they bear. Therefore, they are not volatile or hazardous to environment.
An instrument used for measuring the refractive index of a material.
The human eye identifies thousands of different colors. However, it is not always easy to interpret these colors to someone and expect him/her to understand the same color. For this purpose color identification systems are developed. See Also Color identification systems
, Color systems
One of the three components used to define a color (other two are "hue
" and "lightness
"). Saturation describes the concentration of color components constituting the hue. The terms chroma and purity are also used in place of saturation.
Reducing the color difference between a trial and a reference color. Color matching can be performed at laboratories by using additive method or can be carried out using computers with the data from the color measurement devices.
A defect in which pigments and/or dyestuffs from the lower coat of paint film diffuse into the upper coat due to the solvents (sometimes resins) and causing unwanted discoloration on the latter. It is important to use dyestuffs with sufficient solvent resistance to prevent bleeding.
An instrument that measures the color by dispersing the light coming from a colored surface to its detector by passing through a prism into its component wavelengths and determining amount of light ray at each wavelength. See Also Colorimeter
Measure of power of a pigment to color. Comparison of color strength of dispersed pigment is made by mixing with dispersed titanium dioxide in equal amount of color pigment.
Systems developed for subjective identification of color. Color identification systems can be divided into two groups. Visual system and mathematical system. Visual system comprises numerous color chips arranged systematically. The color is identified by the nearest resemblance color cards code. Munsell color system and natural color system are the most common visual color identification systems. Mathematical color identification systems based on three dimensional color space while each point in this color space specifies a certain color. CIE Lab is the most common mathematical system used. See Also Munsell color system
, Natural color system
, CIE lab color system
Color range formed by dispersing a polychromatic light (especially the sunlight) through a prism into different colors (i.e., different wavelengths)
Main component of color that makes it possible to perceive color as red, yellow, blue, violet. Besides hue, chroma and lightness are the other components of color. See Also Chroma
Chemical groups present in pigment and dyestuff molecules that can impart color to the molecules.
1) Organic coating containing dyestuff and transparent pigments of several microns applied as a thin layer on mostly wood substrates. Stain is impregnated on wood surfaces by spraying, brush or pad application.
2) Component having a high pigment concentration such that when added to a paint mixture it changes the color.
Obtaining color by adding various concentrations of colorants.
An instrument that measures color characteristics according to the intensity of excitement of three receptor cells in our eyes. Colorimeters define a color using “tristimulus values” which are the blue, green and red present in a color.
Science of flow and deformation of materials.
Additives that modify the film behaviour of organic coatings during production, storage and application. These additives impart shear thinning and thixotropic behaviour to wet paint.
Resol resins are synthesized by reacting phenol compounds with formaldehyde with a phenol/formaldehyde ratio higher than the stoichiometric ratio but lower than the ratio used in novolac type resins. In resol resins part of phenol compounds are methylated.
A test performed to determine whether there is a pigment flocculation or flooding in the wet paint. The paint to be tested is applied on a panel. After a short drying time (flash-off) rub-out test is carried out by rubbing the paint film with a finger while it is still damp but already starting to dry. The pigment flocs, which may present in the paint film will be re-dispersed by rubbing and the active pigment surface will increase leading to an increase in color strength of pigments. Therefore, if defects described above exist in paint film, there would be a color difference between the rubbed and unrubbed area.
A simple paint application tool with a rolling cylindrical core. They are preferred because of their time efficiency. Application viscosity in roller applications should be in the same range of that in brush application. The roller frame is made of fibre reinforced plastic or metal. The pile fabric of roller cover is made of polyester, nylon, mohair or lamb’s wool. Fibre length of fabric is between 5 mm and 20 mm. Furthermore, relatively less skill is required with roller applications.
Rutile is one of the natural forms of titanium oxide (TiO2) with the highest refractive index. When rutile titanium oxide is used with organic resins having a refractive index in between 1.40 and 1.60, white paints with the highest hiding power can be obtained. See Also Anatase
Resistance of a paint film to crack under stress is called toughness. The tests to assess this characteristic property is called toughness test.
Due to the market dynamics as well as the sophistication of paint technologies, industrial coatings market is divided into sub categories. Prestigious UK based research institute Paint Research Association (PRA) defines these categories as, automotive OEM
, automotive refinish
, motorcycles, trucks, buses and other vehicles, rail, marine
, protective coatings, industrial wood coatings, agriculture, construction and earthmoving, pre-coated metal sheet and extrusions, metal packaging coatings
, general industrial coatings. Some fields of activity in the Industrial coatings market in Turkey do not have sizes enough to classify them as seperate market segments. Therefore, they are included in the segment called General Industrial Coatings. See Also General industrial coatings
A precious tree grown in tropic regions in Africa. Its reddish-brown wood resembles Mahogany. It is an extremely durable tree with an attractive surface because of its growth rings. It is used for the production of furniture, musical instruments in addition to interior decoration and parquet flooring. In Turkish furniture sector, it is also called “sapelli”.
Shift of color of cured organic coating films to yellowish side under the influence of outdoor conditions.
Although its wood is easily processable, it has a low mechanical strength. Its timber is used for mould making in construction, package industry and wood chip production.
An oscillating pendulum, which is in contact with the paint film through two semi spherical touch points, damps according to non-elastic response of the paint film in due course and eventually stops. The time passed for the swing of the pendulum to be damped, is accepted as a measure of paint film hardness.
Property of a material by which all the incoming light to its surface passes through, without any loss from reflection and absorption. Paints with small pigment particles and clearcoats are expected to highly transmit the light. Therefore, either transparencies of paint films applied on a glass are visually compared or instrumental measurements are performed for assessing transparency.
Number average molecular weight is found by summing the products of the number of molecules and molecular weights of each group containing equal molecular weights divided by the sum of thenumber of molecules in the polymer mixture.
Paint produced using pearlescent pigment, in order to obtain various visual effects depending on the viewing angle.
Pigments produced by coating TiO2 or some other oxides at varying thickness from 120 nm to 160 nm on the mica flakes of 100–500 nm (0,1–0,5 µm) thick. Nacreous pigments are perceived in different colors and sheen depending upon the viewing angle. Mica based nacreous pigments impart color to the coating by light interference caused by mica flakes of the same thickness with the wavelengths in visible light spectrum (100–500 nm). See Also Effect pigments
Its wood is resistant to weather conditions and decaying. The odor of cedar oil keeps moths away therefore it is used for the production of wardrobes as solid wood or veneer. Besides, due to its odor absorption property, shoe cabinets are made of cedar. Some types of cedar wood are used to produce guitar body and headstock.
An exterior durable, thermoplastic resin formed by the reaction of cellulose with acetic acid and butyric acid. It is used in automotive OEM and automotive refinish coatings as basecoat in addition to wood varnishes. See Also Cellulosic resins
Thermoplastic resin formed by the nitration of raw cellulose with sulphuric acid and nitric acid. Nitration to a level of 10,7%-12,3% Nitrogen is used in cellulose nitrate resins for paint industry.
Paints in which cellulose nitrate is the main binder. Cellulosic paints cure by evaporation of solvent. The flexibility of cellulosic paints are increased by adding alkyd resins and plasticizers into their formulation.
Resins synthesized by reaction of acids and alcohols with cellulose, which is typically gathered from cotton and wood. Cellulose nitrate (nitrocellulose) resins are the most widely used type. Other types include cellulose acetobutyrate (CAB), ethyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose resins
Paints produced using synthetic resins as binders instead of natural oils or resins, during the first period of industrialized paint production. Since, first resins that became widespread were alkyd resins, historically, synthetic paints and alkyd resin terms are used interchangeably. Although most of the paint resins used nowadays are synthetic, use of synthetic paint term for defining alkyd resins is still common.
Wax polymers produced synthetically for various purposes. Polyethylene, polypropylene, polytetrafluoroethylene and polyvinyl acetate are frequently used in paint industry to increase scratch resistance in addition to matting and rheology modification. See Also Wax
Basket mills are wet grinders consisting of an agitator disc connected to a vertical shaft. They work by immersing the agitator disc into a pigment or extender paste. Basket assembly is filled with high density milling beads, and the external part contains a slotted sieve which allows pigment paste to pass but not the milling beads. Basket mills are designed such that vacuum created by rotating disc, causes the paste to enter the basket from the upper surface. In addition to basic concept, some basket mill producers have different designs that impart extra features.
Tanning is the process of making leather, which is a raw material in textile industry, by removing the flesh, fat and the hair from the skins of animals by using chemicals and making them durable against degradation by microorganisms.
The volume, which is excluded from the volume occupied by the molecules in the total bulk volume of polymer and its solution.
The most common type of addition polymerization. Monomers transform into free radicals and become activated with the help of an initiator and the polymerization starts.
Transition of liquid organic coating on a surface, into a tough and durable dry film. Curing may take place (a) by solvent evaporation in liquid paints (b) by melting of coated powder into a film and then cooling to ambient temperature in powder coatings. (c) by polymerization reaction happening inside the film in liquid paints or powder coatings that contain heat-curing resins.
Component that starts hardening by cross-linking when mixed with binder containing component known as first component. Hardener may consist of cross-linkers or a catalyst.
Measure of resistance of a paint film to scratch, indentation and fatigue deformation.
Vast majority of tests for measuring the hardness of organic coatings are based on the following three principles: scratch resistance, indentation resistance and fatigue resistance against periodic deformation.
Widely used scratch resistance test is the pencil hardness test. Pencils with varying hardnesses are used to scratch the paint film. The hardness of the film is reported as the grade of pencil that does not cause any scratching on the surface.
In indentation resistance tests, an indenter harder than the organic coating is forced against the film under a fixed load. The size of the indentation indicates the resistance of the paint. Buchholz hardness test and Tukon (Knoop) hardness test are the most known indentation hardness tests.
Pendulum hardness test is the most common test relateed to fatigue resistance against periodic deformation. The damping time or number of swings made by the pendulum required to make permanent deformation of paint film under periodic load is determined.
See Also Pencil hardness
, Buchholz hardness
, Knoop hardness
, Pendulum hardness
Although their particular solvency is moderate, when mixed with strong solvents they do not affect the solvency. Diluents are used in conjunction with thinners to reduce cost.
It is the process of coating iron or carbon steel with a thin zinc layer, by passing the metal through a molten bath of zinc at a temperature of around 460°C. Since Zinc is more prone to corrosion than iron or steel, zinc layer acts as a sacrificial anode and protects the metal from corrosion.
Sheet shaped products obtained by passing carbon steel billets heated above their recrystallization temperature, through a set of work rolls so that thinner cross sections form.
Hiding of paint over the real subtrate to be coated is called industrial hiding. It is determined by applying gradually increasing subsequent layers on the real substrate (sometimes it can be a bare surface or primed surface with a certain color.) If the color difference obtained by color measuring device, between two subsequent layers (a thicker film after a thin film) is less than 0.3 (DE<0.3), the film thickness at that point is defined as industrial hiding.
Paint that is applied on the back surface of metal coils to protect this side from corrosion.
Polyol that is used in exterior-use industrial coating polyesters which require high water and UV resistance.
Chemical name: 1,4-cyclohexane dimethylol, 1,4-dimethylcyclohexane
Melting point: 35°C
Alcohol that can dissolve many natural resins, cellulose ethers and phenol formaldehyde resins.
Boiling range: 160°C; Evaporation number based on the ether: 28; Specific gravity: 0,942; Refractive index: 1, 4191; Flash point: 63°C
Cyclo aliphatic ketone solvent used in solvent-borne coatings.
Chemical name: Cyclohexanone
Boiling point: 156,7°C; evaporation number relative to ether: 40; specific gravity: 0,948; refractive index: 1,4500; flash point: 43°C
Abridged name of silicon dioxide, which is an abundant mineral on earth. In paint industry, porous and pyrogenic silica and colloidal silica produced by burning of organosilicone compounds, are used to adjust sagging, leveling and settling behavior of paint. Larger and grinded in micron scale silica dust is used as a matting agent. Precipitated silica in proper solvent and/or resin vehicle is used to improve scratch and flame resistances of paints.
Quartz powder which is obtained by grinding amorphous quartz is widely used in paint industry as matting additive. Furthermore, SiO2 based on diatomaceous earth is used for the same purpose. Moreover, pyrogenic silica obtained by burning of silicon tetrachloride (SiCl4) is used as rheology modifier in paints.
Alkali metal silicates like sodium and potassium silicates have limited use as inorganic paint binder. Furthermore, ethyl silicate is used as a binder in anti-corrosive paints, especially in high corrosion resistant zinc-rich primers.
Heat resistant coating resins produced by copolymerization of silanediol and silanetriol in different ratios. Hardness, flexibility, chemical and heat resistance as well as solubility depends on hydrocarbon segments borne by silane compounds and diol/triol ratio.
Paint application performed by using three parallel rollers named as pick-up, feeding and applicator. Pick-up roller immersed in paint pan, moves around its axis and transfers the paint to the feeding roller which it is in touch with. Feeding roller transfers the paint to the applicator roller in contact with it. Application roller, transfers the coating onto the material to be coated which is moving on a conveyor belt. See Also Direct roller application
, Reverse roller application
Empty space in engine room and one meter high from the engine room floor in ships. Oil, fuel, dirty water as well as clean and seawater leaked from engine and its components or emptied water during maintance is drained in bilge.
Sheet shaped products obtained by passing carbon steel billets below their recrystallization temperature, through a set of work rolls so that thinner cross sections form. Sheets produced by cold-rolling have higher sagging resistance and harder than hot-rolled steel.
Due to outdoor effects, especially UV light and chemicals, pigments degrade. This degradation leads to decrease in saturation of color and is called fading.
Solvent mixture obtained in a boiling range of 150-195°C during distillation of petroleum products rich in aromatics. Evaporation number based on the ether: 35-46; Specific gravity: 0,872-0,875; Refractive index: 1, 50; Flash point: ~42°C. (Commercial samples: Solvesso 100, Shelsol A etc.)
The last coat applied in a coating system. Since topcoats are exposed directly to the outdoor conditions, they are expected to have certain durability.
Soybean oil is a vegetable oil extracted from soybeans. It is used in food industry and synthesis of alkyd resins. Soybean oil is semi-drying oil, which have a similar fatty acid composition and drying characteristics to sun flower oil. Soybean oil contains %51 of linoleic acid (two unsaturated bonds) and %25 oleic acid (single unsaturated bond).
Paints that can provide protection for a certain time to the surface on which they applied and after this period, they can be easily removed from the surface.
Removal in sheets of cured organic coating from the surface.
Colors in the visible color spectrum each of which are lights of certain wavelength.
In wet paint applications, a spray dust fallen on a still wet paint film from the paint itself or another paint applied nearby at the same time may cause visual defects as particles , craters or orange peel. The property of a paint causing this phenomenon is known as spray dust sensitivity.
A monomer used as a precursor or a modifier in the synthesis of most polymers.
Chemical name: phenylethene, vinyl benzene
Boiling point: 145°C
Resistance of a paint film against degradation and failure caused by water.
Wetting of paint film becomes difficult when surface tension of paint film is lower than that of water and the paint film does not include any water-soluble impurities. In order to specify the difficulty of wettability of paint film, sometimes paint film is defined as water repellent.
Regional appearance change on paint film caused merely by water.
General name of materials that have a tendency to absorb water or a strong affinity to water.
General name of materials that do not have a tendency to absorb water or a strong affinity to water.
Waterborne coatings are defined as coatings in which water is used for adjusting flow behaviour instead of organic solvents. They are subdivided into three groups as latex coatings, water reducible coatings and, emulsion coatings. Waterborne coatings are commonly misnamed as water based coatings. This term is misleading because basis of something is the inherent element that determines its characteristics, whereas water leaves the paint during drying.
Paints in which waterborne emulsion polymers are used as binders.
Waterborne emulsion polymers are suspensions of small polymer droplets which are stabilized by emulsifiers in water. If the polymerization occurs in the droplets formed by raw materials, the emulsion is called “primary emulsion”. If the solution of a solventborne polymer is emulsified in water, than it is called “secondary emulsion”.
Panels with various thicknesses, produced by mixing wood chips with certain chemical binders and compressing. It is frequently used in furniture sector. Chipboards have poor resistance against water and flame.. Kitchen cabinets, wardrobes and shelves that are used for carrying lightweight objects, some office furnitures and shelves are made from chipboard.
Water reducible paints contain water reducible polymers as well as water miscible solvents such as alcohol or glycol generally below 15%. Water reducible paints, can be reduced using water before application. They are commonly misnamed as water soluble paints.
Resins, which are made water reducible by adding sufficient amount of hydrophilic groups into their structure.
During obtaining of wooden materials, if the cutting direction is parallel to the grain direction of wood, it is called edge cutting. See Also End cutting
Phase transition of a solid element or compound to gas phase without passing through liquid stage.
A paint defect appearing as whitening on the paint and varnish surfaces when paint application is performed at high relative humidity. It is seen in solventborne coatings. After application, solvent evaporation lowers the substrate temperature causing moisture in the air to condense on the paint film which, in turn causes precipitation of organic binder.
Test for evaluating the abrasion resistance of paint films. A certain mass loaded abrading wheel rolls on painted panel mounted on a on a rotating turntable. After a certain number of revolutions, weight loss due to abrasion is determined.
Tests which can be performed by not causing damage to the object to be evaluated.
Magnesium silicate mineral containing crystal water Mg(SiO10)(OH)2 or 3Mg.4SiO2.H2O. It is found in spherical, lamellar and fibrous formed crystal structures. Refractive index: 1,54-1,59; specific gravity: 2,70-2,85; oil absorption value: 23-52 g/100 g talc. It enhances sanding of paint, primer and putties. Due to its high oil absorption value, it increases the viscosity of paint and provides active matting.
Wood oil obtained as a byproduct of the alkali process of wood pulp (Kraft process) manufacture. After decolorization by distilation, tall oil and its fatty acids are used in alkyd resin production. Tall oil is a semi-drying oil with a fatty acid composition of 30% oleic acid, 45% linoleic acid and 14% pinoleic acid.
Hardening of an organic coating film to a degree at which it has its ultimate physical and chemical properties.
If two colors mixed in a proper proportion, result in a neutral color then they are called complementary colors. . For instance, when two lights with complementary colors are mixed, white light forms. On the other hand, when two paints with the complementary color are mixed, black paint is obtained.
Paints applied to various agricultural machines, tankers, valves, tanks, plows and other agricultural equipment in addition to some parts of agricultural hand tools like shovel, scissor and handsaw. Paints for agricultural tools are designed to have high resistance against wear, chemicals and corrosion.
Total quality arisen from the predicted qualifications of a product or a service during the design stage. For instance, a pizza shop could be founded to take orders of 10 different pizzas of which ingredients are predefined, via internet and deliver these orders to all locations in the city within 20 minutes in a hot and hygienic condition. (See Peelable coatings
). On the other hand, another pizza shop, could be founded to serve pizzas in the shop in which its temperature is held constant in summer and winter at 25ºC and there are fresh flowers in a vase at each table. Customers choose the ingredients of pizza and they will be served at most 15 minutes. The difference between two services is stem from the difference between their design qualities.
See Also Production quality
Resistance of coatings especially applied on exterior parts of vehicles, against the impacts by stones thrown-up from road. The paint film should have strong and elastic chemical bonds so that the impacts are damped without deforming the coating. Therefore, aliphatic polyurethanes are preferred for high stone chip resistant coatings.
Fluid medium in which pigment powders are dispersed. In liquid paints, vehicle comprises binder and solvent. In powder coatings, binders that can be fluidized by heat are used as vehicle.
It is used to specify a color change along the depth of the film due to the migration of one or several pigments to the surface more than other pigments. When rub-out test is performed on a wet paint film with flooding, one can see an indistinct color change on the rubbed region by looking the paint-glass interface behind the glass. On the other hand, a more certain color change can be seen at paint-air interface.
Chalk is obtained from shell remains of marine microorganisms and is composed mostly of amorphous calcium carbonate (CaCO3). It is used as an extender in interior-use architectural coatings.
A paint defect occurs when some of the paint resin types decompose on exposure to UV light, temperature differences and oxygen, and becomes powder-like, and leaves the film.
In this paint production approach, a resin with a high compatibility range is selected as main dispersion resin and different pigments are dispersed separately to a certain grain size using this resin. Color matching is performed using this pigment pastes and letdown is done by adding remaining ingredients after a proper calculation. The main advantages of this approach are, better optimization of capacity of production equipment (especially the mills) and storage areas in addition to reduced production times. It is achieved by producing common pigment pastes, which can be used in various product groups owing to the compatible resin used. The drawback of this approach is the difficulties in sensitive color matching because of highly concentrated pigment pastes in addition to the possibility of decrease in color strength, gloss as well as haze and formation of particles due to pigment flocculation during storage.
A simple tool used to remove rust, loose/peeling paint and dirt from the surface to be coated otherwise these can cause difficulty in adhesion. The bristles of wire brush are usually made of carbon steel, stainless steel and brass. (Given in a sequence of use prevalence. Wire brushes are used with rotating and vibrating motors in addition to simply by hand.
Telegraphing is the revealing of surface of the coated part of the substrate through the coating. Sometimes, the showing through of fingerprints, water spots or sanding marks on the substrate is called telegraphing. But these defects are usually manifestations of dewetting. Telegraphing is normally caused by surface tension gradients on the part of the substrate due to the concentration or temperature changes. For instance, when baking a sheet metal surface, if there is a reinforcment element, it will cause that part to have a lower temperature and therefore a higher surface tension. In this case, due to movement towards the high surface tension region (Marangoni effect
), paint film above the reinforcement element will be higher.
A liquid droplet in contact with a solid surface makes an angle at solid-liquid-air triple point. The angle known as contact angle can be measured with goniometer. In paint industry, the contact angle is used to determine surface tension of liquid paint.
Polyacid produced by oxidation of p-xylene. It is commonly used as precursor to polyethylene terephthalate polyesters for textile industry.
Sublimation temperature: 300°C
Sweating is a paint defect where the ingredients of a paint film, which are liquid at room temperature, exude through the surface causing a sweating appearance.
Solvent group obtained from roots and trunks of some of the pine trees and used in long-oil alkyds based coatings. Terpene solvents have the general formula of (C5H8)n. The most widely used terpene solvents are turpentine and Dipentene with an empirical formula of C10H16. In the mean time, use of terpene solvents decreased since they are superseded by petroleum based white spirit.
The impact caused by falling of a weighed plunger from a gradually increased height onto the back of metal panel of a cured paint film is called reverse impact strength. See Also Impact resistance
Paint application method where the applicator rolls run in the opposite direction to the conveyor movement. In this application, better levelling is achieved on the surface because sheer stress exerted on the paint film is higher than in direct rolling application. Reverse roller application method is preferred especially in glossy topcoats. See Also Roller coating applications
, Direct roller application
A phenomenon observed in some of the pseudoplastic fluids is the change in viscosity after an applied shear. If a pseudoplastic fluid is not thixotropic and a constant sheer stress is applied on it (i.e., stirring at a constant speed), its viscosity drops and keeps constant. On the other hand, if fluid is thixotropic, viscosity drop continues after a homogenous stirring is reached. When stirring stops, viscosity of a non-thixotropic fluid rises to its steady value, whereas, thixotropic fluid may need minutes, hours even days to recover its original viscosity.
See Also Shear thinning fluids
, Pseudoplastic fluids
Oxide of titanium having anatase, rutile, ilmenite crystal forms. Rutile crystal structure titanium dioxide is the prime pigment in paint industry. The rutile titanium dioxide used in paint industry is produced by converting the crude ore to high purity titanium dioxide by one of the chemical processes (sulphate process and chloride process).
Paint solvent obtained from coal tar and petroleum rich in aromatics.
Boiling range: 110-111°C; Evaporation number based on the ether: 6; Specific gravity: 0,871; Refractive index: 1,4969; Flash point: 6°C
Polyurethane raw material which is commonly used in coating industry as a mixture of 2,4 and 2,6 isomers with a ratio of 80% and 20%, respectively.
In roller coating applications, pick-up roller immersed in a paint pan, moves around its axis and transfers the paint on its surface as a film. See Also Roller coating applications
In ball mills, ceramic and metal balls of 20-30 mm diameter disperse pigments in a cylindrical container rotating around its horizontal axis. Ball mills are the main equipments that can disperse by both hammering and rubbing. However, due to space they occupy in shop floor, long dispersion times and limited adaptation to the variable capacity batch processes, ball mills are gradually discarded.
Solvent free coatings which use resins with glass transition temperatures higher than room temperature. Powder coatings are comminuted to 20-100 microns. Powders clung to the surface forms a thin film after high temperature baking.
Through these applications, powder coating fluidized by mixing with air is sprayed using a powder gun with an orifice. A high voltage of 40-100 kV connected to a negative electrode at the orifice ionizes air molecules. This cloud of ions is called “corona”. Powder particles pick-up anions when passing through the corona and become negatively charged. Since the object to be coated has become anode because of grounding it attracts particles to its surface. Particles are neutralized when they reach the surface. Loose powder coating film, turns to a tough, durable, continuous, film with good adhesion after baking.
Dust free drying is defined as the shortest time which a dust dropped on a wet film will no longer stick to the surface. Tipping gently with the point finger on the film and the time at which paint does not adhere to the finger is the most frequently used test method to define dust free drying time. If this method is employed, before starting, the point finger should be wiped with a rag wet with acetone and the dampness and skin oil on the finger should be removed. A more practical method is starting a stopwatch after paint is applied. Cotton fibers are dropped on the wet test film from a height of 15 cm. After 10 seconds, cotton fibers are tried to removed by blowing over the test film. If no marks are left on the film, then stopwatch is stopped. Time passed is determined as dust free drying time and it is recorded with the ambient temperature. (e.g., Dust-free drying=5 minutes at 25°C)
General name of components formed by esterification reaction of glycerol with acids, particularly fatty acids, through three hydroxyl groups that glycerol bears. Triglycerides formed by esterification of vegetable fatty acids and glycerol are called vegetable oils.
Surfaces cleaned from oil and dirt are pretreated before paint application. Since use of Cr+6 is restricted, it’s been superseded by phosphate coatings. Among phosphate coatings, the best corrosion resistance and surface adhesion are achieved by tricationic phosphate coatings (zinc-nickel-manganese phosphate). Phosphate coatings can be applied by dipping or spraying. Shape of the formed metal phosphate crystals depends on the application method. In dipping, crystals cover the metal surface as a protective shield made of ordered fish scales. In spray applications, acicular (perpendicular to metal surface) metal phosphate crystals are formed. Therefore, by dipping method, impervious and high corrosion resistant phosphate coatings with high stone chip resistance are formed.
Chemical name: 1,2,4-Benzenetricarboxylic anhydride
Melting point: 167ºC
Polyol synthesized by reaction of formaldehyde with butyraldehyde. Trimethylolpropane is used in the production alkyd resins and isocyanate prepolymers.
Chemical name: 1,1,1- Trimethylolpropane
Melting point: 58,8°C; Boiling point 295°C
Tung oil is vegetable oil obtained from tung tree with a fatty acid composition of 80% eleostearic acid. Eleostearic acid bears three conjugated double bounds. Therefore, it is oxidized by air at room temperature to give tough and durable films. On the other hand, if baked over 120°C, due to self polymerization, tough and durable films are formed.
It is an accelerated test to assess how efficiently the paint film protects the substrate against corrosion. Coated steel panels scribed through the coating, exposing the bare steel, are hung on in a 35ºC chamber by non-metal grids, where they are exposed to a continuous mist of 5% NaCl salt solution. For industrial coatings, after a test period of a few hundred hours to a few thousand hours, the panels are examined for degradation of the paint film and corrosion of the substrate.
Aerospace coatings include primers, top coats and specialty coatings to paint the interior and exterior surfaces as well as various parts of airplanes. Need for high mechanical strength neccessitates the use of low density materials, made use of aluminium alloys, plastic composites and titanium widespread in aerospace coatings. During flights, airplanes are subjected to high grade UV exposure without protected by clouds. Moreover, sudden temperature change is another important parameter. Therefore, in aerospace coatings, primers with good surface adhesion as well as topcoats with high UV durability and flexibility are employed. Aluminium and alloys are preferred because of their low density and high mechanical strength in addition to corrosion resistant nature and their ease of production. Together with aluminium, composite materials produced from different types of engineering polymers and reinforcing materials, magnesium, titanium, and steel are used.
Adjective used for chemicals that have high evaporation rates although liquid at room temperature.
The amount of volatile organic compounds in grams per 1 liter of liquid organic coating.
A test performed to predict the degrading effect of outdoor exposure as UV light, rain/fog and temperature change. Especially, it is a common belief that, degradation of binders during the UV cycle of the test, under high energy radiation which does not exist under natural exposures, disturbs its simulation quality.
Name of the roller which transfers the paint to the sheet to be coated on the conveyor belt. If the application roller runs in the same direction (at different speed) with the conveyor line, the process is called direct roller application, if roller runs in the opposite direction it is called reverse roller application. See Also Direct roller application
, Reverse roller application
The most suitable viscosity at which paint can be applied by the chosen method with ease.
Inclination of two or more substances mixed with each other to form a stabile homogenous mixture. Negative inclination between two or more substances is called “incompatibility“.
Various segments on a molecule make it difficult for other chemically affinic molecules to approach another part on the same molecule. This hindrance completely arises from the shielding effect caused by spatial arrangement of that molecule.
Paint production equipment, which disperses by efficiently grinding the pigment flocs passing through nips of three rollers revolving at different speeds. Although they perform effective dispersion, their use is much more limited today because of their capacity limitations.
Three different receptor cells in the retina of human eye are sensitive to blue, green and red lights. Color spectrophotometers are utilized to measure how much a color comprises these lights. Results will be tristimulus values expressed in X, Y, Z symbols.
Compound produced by reaction of liquid CO2 with ammonia and used in the synthesis of urea formaldehyde resin.
Melting point: 132-136°C
Polymerization product of urea and formaldehyde. Commonly used as adhesives. In addition, they are used as cross-linker in alkyd and polyester baking systems.
Resins that have alkyd, acrylic structures but modified with monomers and prepolymers containing isocyanate groups to improve flexibility, chemical resistance and so on.
Urethane resins are formed by reactions of compounds bearing at least two isocyanate groups with molecules with more than one hydroxyl groups. Urethane coatings have high water, solvent and chemical resistance. Urethane coatings with no aromatic groups have superior UV resistance.
Assessment of how close the characteristics of a product and service are after production process, relative to those projected during design stage. See Also Design quality
1) Transparent organic coating material containing no pigments.
2) Transparent film formed by applying and curing of a clearcoat.
Organic coating resins synthesized by polymerization of unsaturated vinyl groups and their derivatives.
1) Having a high resistance to flow (e.g., viscous fluid)
2) Pertaining to the resistance to flow (e.g., viscous force)
General name of equipment used to measure viscosity of fluids.
Measure of resistance of a fluid against flow. The higher the viscosity of a fluid, the more resistance it has to flow.
Accelerated test for predicting the change in the viscosity of an organic coating during storage. For simulating stability during storage, the paint is kept at 50 – 60ºC for a predetermined time.
Cross-linking of natural and synthetic rubber with sulfur compounds. See Also Natural Rubber
An accelerated test for predicting the exterior durability of the paint in the real service condition. In the UV cycle, the radiation from carbon arc or xenon lamb, is assumed to have the same wavelength distribution as the sun light but more intense Although test time is longer than UV-con test, WeatherOmeter test is accepted as a more reliable test for predicting the exterior durability of paint.
Solvent mixture obtained in a boiling range of 130-220°C of during distillation of petroleum products rich in aliphatics. Long oil alkyd resins based synthetic paints, which can be applied either with a brush or with a roller, are commonly reduced by white spirit.
Chemical name: Hydrocarbon mixture rich in aliphatics. No certain chemical formula exits.
Boiling point: 130-220°C; Evaporation number based on the ether: 85°C; Specific gravity: ~0,750; Refractive index: 1,434; Flash point: 40°C
Quantity of linseed oil slowly added to 100 g of pigment while rubbing with a spatula until reaching a point at which the mixture takes the form of a ball. Oil absorption value, is commonly used for predicting the binder amount for a specified pigment during paint formulation.
Grease on surfaces to be coated, causes poor adhesion for all types of coatings. Therefore, before application, it is important that grease of all kinds should be removed from the surface. First method to degrease before paint application is, wiping/washing the surface with a rag wet with solvent or with a brush. The second method is to remove grease by saponification from the surface by applying hot alkali solution.
Acids that form oils by esterification with polyols. Majority of fatty acids are “vegetable fatty acids” which form vegetable oils by glycerol esterification. Monofunctional vegetable oils having 18 Carbon chain in their backbone are classified according to the number of C=C bond they have, as drying, semi-drying and non-drying. Fatty acids are widely used in paint industry for alkyd resin production.
Amount of fatty acid added to the polyester backbone of alkyd resin. Oil length is defined as the total weight of oil in 100% solids alkyd resin. If oil length is higher than 60%, “long-oil alkyd resin”, between 40% and 60%, “medium-oil alkyd resin”, lower than 40%,“short-oil alkyd resin” is obtained.
Insulating putties found applications in automotive OEM, automotive refinish aerospace industry and water craft industry. Main purpose of using insulating putties is to prevent transfer of water, humidity, chemical and gas by elastically sealing of edge joint points and junction points of coated objects. Furthermore, providing a sound insulation by its flexible and porous (some types) structure and again providing heat insulation by its low heat conductivity and porous (some types) structure are the main purposes of using insulating putties.
State in which two surfaces (i.e., solid-liquid or solid-another solid) held together by attractive forces. Components that results in adhesion are: (a) mechanical component, (b) chemical component, (c) dispersion component, (d) electrostatic component and (e) diffusion component. In any adhesion event, all or some of the components play a role.
Primers applied as a thin layer to promote interlaminar adhesion on surfaces difficult to adhere. The surfaces difficult to adhere are mainly polyolefinic structured plastic surfaces like polyethylene and polypropylene etc. and some aluminium alloy surfaces. Examples of adhesion promoters are chlorinated polyolefin, organosilanes and polyvinylbutyral based primers.
Chemical groups which can be presented in the structure of pigments and dyestuffs and can contribute to color of the compound together with main chromophore groups.
Alkyd resins containing semi-drying oils in their backbone.
General name of oils, formed by reaction of glycerine with fatty acids with limited unsaturation. (Semi-drying oils do not have a certain definition as the drying oils). Practically, it is conveninent to define oils as semi-drying if they have an approximately 1.5 - 2 unsaturation per fatty acid chain.
To complete the electrical circuit during wet paint electrostatic applications, the paint droplets reaching the surface to be coated should transfer the charge to the ground. Thus, the conductivity of the paint should be adjusted using proper solvents and additives.
Test to determine the properties that a paint should have in the package (i.e., viscosity
, solids%, density, fineness of grind
, settling stability etc.)
Density of paints in package or application viscosity. It is measured in g/ml units. Paint density is commonly measured with pycnometer. Pycnometers are constant volume cups made of aluminium or stainless steel.
The thickness of the wet paint film immediately after application. Wet film thickness is commonly measured by Wet Film Comb Gauges with various depth tabs. Another frequently used tool is the Wet Film Thickness Wheel which consists of nested eccentric discs.
Paint application method based on applying a layer without waiting for the previous layer to dry.
Transition of wet paint applied on a surface to a thin film layer due to surface tension and gravitational force. If the paint film is continuous and homogeneous, it is said to be good levelling.
Since a complete homogenization is impossible in materials, there are many anodic and cathodic regions on a surface of every alloy or metal composed of single element but containing a certain amount of impurity. Hence, these neighbouring regions that have different compositions and therefore different oxidation potentials are prone to act as electrodes of a cell. If a liquid layer, even as little as a humidity layer is formed on a metal surface, this systems act as a cell. This type of cell is called as local corrosion cells.
Anti corrosive primer applied on ferrous or light alloy surfaces at 4-7 mm dry film thickness. Since first applications were done by washing the object with the primer, they are called “wash primers”. Wash primers are formulated with polyvinylbutyral as well as epoxy and phenolic resins. In the last two decades, wash primers included zinc phosphate pigments instead of zinc chromates due to hazards caused by Cr+6 to the environment and human health. Wash primers are catalyzed with acid-catalysts for a good adhesion on the metal surface. Applying layers with basic resins on the wash primer films with acid molecules left inside may result in intercoat adhesion failure. Therefore, attention should be paid to wash primer application.
Since water is formed as a side product during this type of polymerization reaction, it is called condensation polymerization. In condensation polymerization, starting from the initiation, in every step during the polymerization, a repeatable unit forms from the reaction of two molecules and this structural unit combines to the chain. Therefore, condensation polymerization is also called “step-growth polymerization”.
Accelerated test for measuring the water resistance of coatings were preformed in test cabinets where the sides of the cabinets are covered with test panels and inside is filled with saturated air at test temperature. Adjusting inside temperature of the cabinet by at least 10ºC higher than outside temperature, condensation of the water vapour in cabinet atmosphere, on the coated surface facing inside is accomplished. Hence, a thin boundary layer is deposited on the coated side of the panel, throughout the test. Condensing humidity tests are carried out at temperatures between 40ºC and 60ºC and for 5 to 20 days.
See Also Non-condensing humidity test
In non-condensing humidity test panels are suspended in the constant temperature cabinets. The air inside the cabinet should be saturated. In this stage, condensation leads to formation of random water films on panels which are also at the same temperature with the inside air. Calling this test non-condensing should not be misleading. Difference between condensing and non-condensing humidity test is, a continuous film formed on panels in the former test whereas random (from place to place or time to time) film formation is seen on the latter test. Temperature and humidity of non-condensing humidity test can be kept in the same range in condensing humidity test. In these tests, it is advisable to evaluate performance of a coating with respect to reference paint.
See Also Condensing humidity test
During the paint production, either in premix or in difficult homogenising processes, high-speed dispersers are utilized. Cowles type dissolver discs are typically used in high-speed dissolvers.
Using 0.2-07 atm pressure instead of 2.5-5.5 atm air in conventional spray guns. But the volume of the low pressure air made is higher. Special channels in the spray gun allow the adequate atomization of low pressure air. Therefore, bounce back effects are reduced and transfer efficiency is increased at low pressure.
General name of liquid paints with a solid content considerably higher than that of the conventional paint. High solids coatings are gaining attention because of reduced effects on environment due to low volatile content and short application times owing to the fact that with high solid content less time is needed to achieve the same dry film thickness. The aim of high solid coating formulation is, achieving application viscosity by adding minimum amount of solvent to the non-volatile constituents. Therefore, use of reactive monomers or oligomers, low molecular weight polymers, dispersion additives that can considerably reduce pigment paste viscosity, in addition to use of solvents that can reduce binder viscosity and reactive diluents which stays in the film by participating in crosslinking reaction are the main strategies in designing high solids coatings.
A common type of polyethylene and it has a less branched structure than LDPE. Nevertheless, its density and crystallization ratio is higher. The tensile strength of HDPE is higher but shape formation and biodegrading properties are lower than LDPE.
Contracted from English word (Surface+active+agent). Surfactants are used to reduce surface tensions of organic coatings. Surfactants comprise one polar group at one edge and one organophilic (high compatibility with solvent and resins) group at another end. They are used in preparation of emulsions, aqueous pigment dispersions and also as defoamers.
Forces which tend to reduce surface area of any liquid. Depending on the type of liquid, all liquids have intermolecular attractions. Molecules deep within a liquid, are attracted equally in all directions by similar neighbouring molecules. Hence, they are in a stage of balanced equilibrium with their surroundings. Nevertheless, a molecule at the surface (the vapour-liquid interface) is pulled only by the molecules under and near and not by those above, due to the fact that vapour phase density is much lower than that of liquid phase. Work should be done against cohesion forces between liquid molecules, to increase the free surface area by taking the molecules to the surface from bulk liquid. Consequently, molar free energy of surface is higher than molar free energy of other parts of liquid. (Note: Another definition of surface tension is the free surface energy per unit surface area of liquid).
There are various methods to determine the surface tension of liquids. Four of them is frequently used in paint industry.
(a) Du Noüy Ring method for liquid paints.
(b) Wilhelmy plate method for liquid paints.
(c) Measuring the contact angle for liquid paints. (Sessile drop method)
(d) Test ink method for cured paint films
Surface additives are added to paint formulation to prevent film defects. They either have surface tensions lower than paint ingredients (silicone and fluoride compounds) or they are compounds having limited compatibility. They migrate to the surface and form a thin layer. Hence, surface tension gradients that cause defects on paint film are prevented.
A process in which unwanted particles presented in paint are retained on a certain mesh size sieve.
Floating is a term used to describe a mottled, splotchy or streaked appearance exhibited by a paint film. Floating is due to separation and uneven distribution of different pigments in the paint. Difference between floating and flooding
is that, in flooding color varies along the depth of the film and the film appears uniform horizontally,owing to migration of one or several pigments to the surface. On the other hand, in floating, changes are localized on the panel and color is not uniform horizontally.
Chemicals that predicted to cause cancer or other serious health issues such as in reproduction system, congenital anomalies or to the environment. Benzene is considered as HAPs and is found as an impurity in liquid petroleum. Perchloroethylene, is emitted from dry cleaning shops, methylene chloride is used as solvent and paint remover. Moreover, dioxins, chromium and lead compounds are also known as hazardous air pollutants.
Sandpaper is a form of paper or cloth where an abrasive material has been embedded to its surface. It is used to remove small amounts of material from surfaces. There are different types of sandpapers for use on bare or painted metal and wood surfaces. Sanding papers are used by mounting on electrically powered rotating discs or by covering it with a wedge for manual operations. The abrading particles on sanding papers are garnet, aluminum oxide or silicon carbide and they come in different grit sizes. Grits are designed by different symbols ranginf from P12 to P2500. The higher the number, the smaller is the grit size.
Sanding is mechanically removing a layer of material from a wood, coated or a metal surface by using sandpaper. Sanding is performed to prepare surfaces to application in paint industry. Thus, by sanding, physical imperfections on the surface and deposited grease that can reduce surface adhesion can be removed. Since, sanding increases surface area by making the surface rougher, adhesion improves further.
They are called as linear polymers as well. Their structure is a linear chain. They are composed of monomers with double functionality (F=2). Typically, they are of thermoplastic type.