Glossary FAQ
Find definitions to technical terms related to coil and extrusion coating products or other industry dialogue.
Coating Terms
- Abrasion:
- Wearing away of a surface in service by action such as rubbing, scraping, or erosion.
- Abrasion Coefficient:
- Method for reporting the result of an abrasion test using the falling sand abrasion tester, in which it is assumed that the abrasion resistance is proportional to the film thickness.
- Abrasion Resistance:
- The ability of a coating to resist being worn away and to maintain its original appearance and structure as when subjected to rubbing, scraping, or erosion
- Accelerated Testing:
- Tests, the conditions of which simulate those encountered in practice, but which have been accentuated artificially to provide performance results in shorter periods of time. Coatings do not necessarily behave under such tests exactly as they will under actual conditions, but any coating which gives good performance under test may be shown to have possibilities which are worthy of further considerations and experiments
- American Society for Testing and Materials (ASTM):
- A non-profit corporation formed for the development of standards on characteristics and performance of materials, products, systems, and services, and the promotion of related knowledge. In ASTM terminology, standards include test methods, definitions, recommended practices, classifications, and specifications.
- Barrier Coat:
- Coating used to isolate a paint system from the surface to which it is applied in order to prevent chemical or physical interaction between them.
- Blistering Resistance:
- The ability of a coating to resist the formation of dome-shaped, liquid-or-gas filled projections in its film resulting from local loss of adhesion and lifting of the film from the underlying surface or coating.
- Butyl Acetate:
- Limpid, colorless liquid with fruity odor. Prepared by heating and distillation, after contact of n-butyl alcohol with acetic acid in the presence of a catalyst such as sulfuric acid. Solvent used in production of lacquers, natural gums and synthetic resins.
- Chalking:
- (1)Formation of a friable powder on the surface of a paint film caused by the disintegration of the binding medium due to disruptive factors during weather. (2) A condition of printing ink in which the pigment is not properly bound to the paper and can be easily rubbed off as a powder. (3) Formation of a powdery surface condition due to oxidation of the surface of rubber and release of pigments and filler at the surface. Chalking is caused by a degradation of the resin system at the surface of the finish. Resin degradation is caused predominantly by the harmful Ultra Violet (UV) rays of the sun. Acid rain and pollution, salt spray, and abrasion by airborne particulate are other contributors to resin degradation.
- Chalking Resistance:
- The ability of a coating to resist the formation of a friable powder on the surface of its film caused by the disintegration of the binding medium due to degradative weather factors. The chalking of a coating can be considerably affected by the choice and concentration of pigment and binding medium.
- Chemical Resistance:
- That property of coating materials to withstand the attack of specified chemicals.
- Clear Coating:
- Transparent protective and/or decorative film.
- Cleveland Condensing Humidity Cabinet (CCH):
- An accelerated weathering apparatus which operates on a condensation type of water exposure at elevated temperature.
- Climate Cabinet:
- Any enclosure used to simulate selected climatic conditions.
- Coating:
- (1)Generic term for paints, lacquers, enamels, printing inks, etc. (2) A liquid, liquefiable or mastic composition which is converted to a solid protective, decorative, or functional adherent film after application as a thin layer.
- Coating, Spray:
- The process in which a substrate is sprayed with the coating material.
- Coil Coating:
- Process wherein a continuous coil of metal is unwound, cleaned, surface-treated, coated, heat-cured, cooled and rewound in one operation. The coated coil is subsequently unwound and formed into any number of products, such as house siding, venetian blinds, and automotive and appliance parts.
- Color Match:
- Pair of colors exhibiting no perceptible difference when observed under specified conditions. The quality of an attempted match is described by the closeness to this ideal match.
- Color Measurement:
- Physical measurement of light radiated, transmitted, or reflected by a specimen under specified conditions, and mathematically transformed into standardized colorimetric terms which can be correlated with visual evaluations of colors relative to one another. Although the term "color measurement" is normally used, color itself cannot be measured.
- Corrosion:
- The deterioration of metal or of concrete by chemical or electrochemical reaction resulting from exposure to weathering, moisture, chemicals, or other agents in the environment in which it is placed.
- Corrosion Resistance:
- Ability of a substance to resist deterioration because of a reaction with its environment.
- Cracking:
- (1) Generally, the splitting of a dry paint or varnish film, usually as a result of aging. The following terms are used to denote the nature and extent of this defect: Hair-cracking. Fine cracks which do not penetrate the top coat; they occur erratically and at random. Checking. Fine cracks which do not penetrate the top coat and are distributed over the surface, giving the semblance of a small pattern. Cracking. Specifically, a breakdown in which the cracks penetrate at least one coat and which may be expected to result ultimately in complete failure. Crocodiling or alligatoring. A drastic type of crazing, producing a pattern resembling the hide of a crocodile. (2) The process of breaking down certain hydrocarbons into simpler ones of lower boiling points, by means of excess heat, distillation under pressure, etc., in order to give a greater yield of low boiling products than could be obtained by simple distillation. (3) Cracking is also the treatment of rubber, uncured and cured, by passing it through moving corrugated rolls, as in preparing tires and other vulcanized rubber for reclaiming.
- Cracking Resistance:
- The ability of a coating to resist breaks of the film where the breaks extend through to the surface painted and the underlying surface is visible. The use of a minimum magnification of 10 diameters is recommended in cases where it is difficult to differentiate between cracking and checking.
- Creep:
- Dimensional change with time of a material under load, following the initial instantaneous elastic or rapid deformation.
- Curing Time:
- Time necessary for curing.
- Denatured Alcohol:
- Ethyl alcohol to which a denaturant, e.g., methyl alcohol, pyridine, etc., has been added.
- Epoxy:
- Group having the oxirane structure.
- Erosion:
- (1) Wearing away of the top coating of a painted surface, e.g., by chalking, or by the abrasive action of windborne particles of grit, which may result in exposure of the underlying surface; (2) Phenomenon manifested in paint films by the wearing away of the finish to expose the substrate or undercoat. The degree of failure is dependant on the amount of substrate or undercoat visible.
- Erosion Resistance:
- The ability of a coating to withstand being gradually worn away by chalking or by the abrasive action of water or windborne particles of grit. The degree of resistance is dependant upon the amount of coating retained.
- Ethyl Acetate:
- Solvent for nitrocellulose and for phenolformaldehyde resins in industrial alcohol.
- Exposure Tests:
- Tests which are conducted to evaluate the durability of a coating or film. They include exposure to ultraviolet light, moisture, cold, heat, salt water, mildew, etc. They can be generated either naturally or artificially.
- Exterior Finishes:
- Coatings which are expected to possess reasonable durability when exposed to natural weathering.
- Fabricate:
- To work material into a finished form by machining, forming, or other mechanical operations.
- Fading:
- Subjective term used to describe the lightening of the color of a pigmented paint following exposure to the effects of light, heat, time, temperature, chemicals, etc. The observed fading may result from deterioration of the pigment, from deterioration of the vehicle, or from a decrease in gloss. A separation of the vehicle from the pigment particle in the interior of the film, with the subsequent introduction of microvoids which scatter light, may also be interpreted visually as fading.
- Film:
- (1) A layer of one or more coats of paint or varnish covering and object or surface. (2) Any supported or unsupported thin continuous covering or coating.
- Film Integrity:
- Continuity of a coating free of defects.
- Film Thickness:
- Thickness of any applied coating, wet or dry.
- Film Thickness Gauge:
- Device for measuring film thickness; instruments for measuring either wet or dry films are available.
- Flash Point:
- The lowest temperature of a liquid at which it gives off sufficient vapor to form an ignitable mixture with the air near the surface of the liquid or within the vessel used. The flash point can be determined by the open cup or the closed cup method. The flash point determined by the open cup method is usually somewhat higher than the closed cup method. The latter is commonly used to determine the classification of liquids which flash in the ordinary temperature range.
- Flexibility:
- Degree to which a coating after drying is able to conform to movement or deformation of its supporting surface, without cracking or flaking.
- Flexibility Test:
- Test applied to films to ascertain if they are able to accommodate elongations without fracture. Flexibility is usually determined by bending the film, applied to a suitable piece of thin metal, around one or a series of rods or mandrels or a special conical mandrel in a specified time.
- Flop:
- Where two different painted panels appear to be a good match for color when viewed at a given angle, but appear different at all other angles.
- Flop Color:
- Used to describe the color observed on paints (particularly metallic paints) when they are viewed near to the grazing angle, i.e., nearly parallel to the surface. The term is generally used in contrast to the terms "face color" or "top color", the color observed when viewing the surface at an angle near to the perpendicular.
- Galvanic Corrosion:
- Increased corrosion above normal corrosion of a metal that is associated with the flow of current to a less active metal in the same solution and in contact with the more active metal.
- Gloss:
- Subjective term used to describe the relative amount and nature of mirror-like (specular) reflection. Different types of gloss are frequently arbitrarily differentiated, such as sheen, distinctness-of-image gloss, etc.
- Glossmeter:
- An instrument for measuring the degree of gloss in relative terms.
- Gloss Retention:
- Degree to which the original sheen of a coating is retained.
- Gray Scale:
- An achromatic scale ranging from black through a series of successively lighter grays to white. Such a series may be made up of steps which appear to be equally distant from one another (such as Munsell Value Scale) or may be arranged according to some other criteria such as a geometric progression based on lightness. Such scales may be used to describe the relative amount of difference between two similar colors.
- Hardness:
- Ability of a coating film, as distinct from its substrate, to resist cutting, indentation or penetration by a hard object.
- Impact Resistance:
- Ability of a coating to resist a sudden blow. Ability to resist deformation from impact.
- Impact Test:
- Used to access the adhesion and flexibility of applied coatings. A weighted plunger is allowed to fall from a specified height onto the front (direct) or back (reverse) of a coated panel. The extent of the damage caused by the impact is used as a basis for assessing the adhesion and flexibility.
- Industrial Finishes or Coatings:
- Coatings which are applied to factory-made articles (before or after fabrication), usually with the help of special techniques for applying and drying-as opposed to trade sales paints.
- Lightfastness:
- (1) The relative degree of change or lack of change in color of materials exposed to the same amount and character of light. Thus, lightfastness is a relative term dependent on conditions which must be defined. (2) Ability to withstand color change on exposure to light.
- Matching, Color:
- Act of making one material appear to match another color. If the achieved match is dependent on the conditions of illumination and viewing, the match is termed conditional or metameric. If the achieved match is independent of the quality of the illuminant viewer, or viewing conditions, the match is termed nonconditional or nonmetameric.
- Matte Finish:
- A coating surface which displays no gloss when observed at any angle; perfectly diffusely reflecting surface. In practice, such perfect surfaces are extremely difficult to prepare. Hence, the term is applied to finishes which closely approach this ideal.
- Metallic Paint:
- Paint which, on application, gives a film with a metallic appearance. This effect is normally produced by the incorporation of fine flakes of such metals as copper, bronze or aluminum. The aluminum used may be leafing or nonleafing, the former giving a far more brilliant metallic effect. These metals can be used in tinted or colored media to give polychromatic finishes.
- Metallic Pigment:
- Particle or flakes of nonoxidized metals or alloys used as pigments to modify the optical characteristics of a paint, to hide the substrate, modify the color or adjust other properties. The metals most commonly used are aluminum, bronze and zinc.
- Metamerism:
- A phenomenon exhibited by a pair of colors which match under one or more sets of conditions, be they real or calculated. Metamerism should not be confused with "flair" or color constancy, which terms apply to the apparent color change exhibited by a single color when the spectral distribution of the light source is changed or when the angle of illumination or viewing is changed.
- Methanol:
- Colorless, flammable, poisonous liquid used as a solvent, in the manufacture of formaldehyde, in organic synthesis, and for denaturing (rendering impotable) ethanol for industrial use.
- Methyl Isobutyl Ketone:
- Medium-boiling solvent.
- Pearlescent:
- An appearance resembling that of natural pearls or mother-of-pearl. It results from the specular reflectance of alternating thin layers of differing refractive index.
- Pearlescent Pigment:
- Used to obtain pearly luster, iridescent effects and metallic sheen. The pigment particles are transparent, thin platelets of high refractive index which partially reflect and partially transmit incident light; simultaneous reflection from many layers of oriented platelets creates a sense of depth that is characteristic of nacreous luster.
- Pencil Hardness:
- A measure of coating hardness based on the scratching of the film with pencil leads of known hardness. The result is reported as the hardest lead which will not scratch or cut through the film to the substrate.
- Perchlorethylene:
- Used for vapor degreasing and dry cleaning.
- Plastisol:
- A suspension of a finely divided resin in a plasticizer, that can be converted to a continuous film by the application of heat. Distinct from baking enamels, etc., in that substantially all the original mixture becomes a part of the film: there is no significant evaporation of solvent. The films are usually much thicker than obtainable from coatings which depend on the evaporation of a volatile solvent.
- Polyvinylidene Fluoride:
- "Thermoplastic fluorocarbon polymer derived from vinylidene fluoride. In film form it is characterized by superior weather and UV resistance.
Abbreviation: PVDF"
- Pretreatment:
- Usually restricted to mean the chemical treatment of unpainted metal surfaces before painting.
- Primer:
- "1) First complete coat of paint of a painting system applied to a surface. Such paints are designed to provide adequate adhesion to new surfaces and are formulated to meet the special requirements of the surfaces. The type of primer varies with the surface, its condition, and the total painting system to be used. Thus, primers for new wood and certain other surfaces must provide for exceptional absorption of medium. Primers for steelwork contain special anti-corrosive pigments, such as red lead, zinc chromate, zinc powder, etc.
2) Coating applied to a surface, prior to the application of an adhesive, to improve the performance of the bond."
- Resin:
- 1) General term applied to a wide variety of more or less transparent and fusible products, which may be natural or synthetic. They may vary widely in color. Higher molecular weight synthetic resins are presently more generally referred to as polymers. 2) A solid, semisolid, or pseudosolid organic material that has an indefinite and often high molecular weight, exhibits a tendency to flow when subjected to stress, usually has a softening or melting range, and usually fractures conchoidally. 3) In a broad sense, the term is used to designate any polymer that is a basic material for coatings an plastics.
- Roof:
- The cover of a building, including the roofing and all other material and construction (such as supporting members) necessary to carry and maintain it on the wall or uprights.
- Roofing:
- 1) Any material used as a roof covering (such as shingles, slate, sheet metal, or tile) to make it wind- and waterproof, and often to provide thermal insulation. 2) A roof.
- Sheen:
- An attribute of object mode of appearance which is similar to luster: gloss with poor distinctness-of-image reflectance. Frequently, in the paint industry, sheen is used synonomously with "low-angle sheen", a characteristic where a material appears to be matte when illuminated and viewed near to the perpendicular, but appears to be glossy when illuminated and viewed at an angle near the grazing angle, such as 85° off the perpendicular. Sheen is therefore frequently evaluated in terms of gloss measurements made on a 75° or 85° gloss meter.
- Solvent:
- Liquid, usually volatile, which is used in the manufacture of paint to dissolve or disperse the film-forming constituents, and which evaporates during drying and therefore does not become a part of the dried film. Solvents are used to control the consistency and character of the finish and to regulate application properties.
- Spectrophotometer:
- Photometric device for the measurement of spectral transmittance, spectral reflectance, or relative spectral emittance. Spectrophotometers are normally equipped with dispersion optics (prism or grating) to give a continuous spectral curve.
- Specular Reflection:
- Light striking a surface, and being reflected or turned back at an angle equal to the angle of incidence.
- Test Fence:
- An apparatus consisting of a fence strategically located in a part of the country for specific weather conditions (temperature, humidity, sunlight duration, etc.) and facing a specific direction and angle. It contains a series of exposure racks (q.v.) on which test panels are exposed. Coated test panels on various substrates (wood, metal, plastic, cementitious, etc.) are tested for exterior durability properties such as chalk resistance, tint retention, adhesion, cracking, peeling, etc. The panels are exposed for various durations of time. Typical directions are north and south. Typical angles are vertical, horizontal, 5° and 45°. Examples of U.S. test fence locations include, Arizona, Delaware, Florida, New Jersey, Pennsylvania and Puerto Rico.
- Top Coat:
- The coating intended to be the last coat applied in a coating system; usually applied over a primer, undercoaters, or surfaces.
- Turpentine:
- A colorless, volatile oil distilled from the products of certain pine trees and consisting primarily of a complex mixture of terpene hydrocarbons of the general formula. Turpentine was formerly extensively used in paints and varnishes but has now been largely replaced by mineral spirits or white spirit. Four kinds of turpentine are now recognized: (1) Gum Turpentine or Gum Spirits. Obtained by distilling the crude exuded gum or oleoresin collected from living trees; (2) Steam-distilled Wood Turpentine. Obtained from the oleoresin within the wood of pine stumps or cuttings, either by direct steaming of the mechnically disintegrated wood or after solvent extraction of the oleoresin from the wood; (3) Sulfate Wood Turpentine. Recovered during the conversion of wood to paper pulp by the sulfate process; (4) Destructively Distilled Wood Turpentine. Obtained by fractionation of certain oils recovered by condensing the vapors formed during the destructive distillation of pine wood.
- Ultraviolet:
- Radiant energy below about 380 nm; portion of the electromagnetic spectrum between about 10 and 400 nm. The term "ultraviolet light" is incorrect because light refers only to visible radiant energy.
- UV:
- Abbreviation for ultraviolet radiation.
- Viscosity:
- (1) State or quality of being viscous. (2) The property of a fluid whereby it tends to resist relative motion within itself. If different layers of fluid are moving with different velocities, viscous forces come into play, tending to slow down the faster-moving layers and to increase the velocity of the slower-moving layers. The constant of proportionality is called the coefficient of viscosity of the fluid. Measured in newton seconds per square metre (SI units) or poise (c.g.s units).
- Weathering:
- Behavior of paint films when exposed to natural weather or accelerated weathering equipment, characterized by changes in color, texture, strength, chemical composition, or other properties. Natural outdoor weathering tests are normally carried out at selected exposure sites, on painted panels, generally exposed either vertically or at 45° facing south in the northern hemisphere.
- Weather-Ometer:
- An apparatus in which specimen materials can be subjected to artificial and accelerated weathering tests which simulate natural weathering, by the use of controlled cycles of ultraviolet radiation, light, water, and heat. Electric arcs, water spray, and heating elements are used to simulate the natural conditions of sun, rain, and temperature changes.
- Weather Resistance:
- The ability of a material, paint film, or the like to withstand effects of wind, rain, sun, etc., and retain its appearance and integrity.