With a state-of-the-art analytical laboratory, Plasticolors can provide technical assistance when it is most needed.
Read MoreLet our team of color scientists assist you with your color requirements.
Read MoreOur team of technical representatives lends support and service to assure the success of every program.
Read More
|
Acid Resistance
|
The ability of a plastics material to withstand attack by an acid. Most plastics have a high degree of acid resistance.
|
|
|
|
|
Absorption
|
Process by which light is converted into heat when striking or passing through an object.
|
|
|
|
|
Acid Test
|
The measure of free acid content of a substance. Free acid is expressed as the number of milligrams of base used to neutralize the free acid present in a substance. This value, also called acid number, is sometimes used in connection with the end-group method of determining the molecular weight of polyesters.
|
|
|
|
|
Additive Color
Mixture
|
The color which results from the addition of two or more colored lights
|
|
|
|
|
Alkyd
|
The term derived from the names of the combining functional groups in alcohol and acids.
|
|
|
|
|
Anionic
|
Pertaining to any negatively charged atom, radical or molecule; or to any compound or mixture containing negatively charged groups.
|
|
|
|
|
Appearance
|
The manifestation of the nature of objects and materials through visual attributes such as size, shape, color, texture, glossiness, transparency, opacity, etc.
|
|
|
|
|
Aromatic
Compounds
|
A class of organic compounds containing an unsaturated ring of carbon atoms. Included are benzene, naphthalene, anthracene and their derivatives. The term aromatic stems from the fact that many of these compounds have an agreeable odor.
|
|
|
|
|
Artificial
Weathering
|
The process of exposing plastics to continuous or repeated environmental conditions developed by laboratory methods designed to simulate conditions encountered in actual outdoor exposure. Such conditions include temperature, humidity, moisture, light in the ultraviolet range, and direct water spray.
|
|
|
|
|
Automotive
Refinish
|
Paints not applied to vehicles by the OEM.
|
|
|
|
|
Binder
|
An adhesive material used for holding particles of dry material together. For example, resinous adhesives used in DriLuxeÒ are called binders.
|
|
|
|
|
Black
|
Ideally, the complete absorption of light energy; the absence of any reflection.
|
|
|
|
|
Bleeding
|
The diffusion of color from a plastic article into a surrounding surface or part, caused by inherent solubility of the pigment in one or more ingredients of the composition. The terms migration, crocking, blooming, and bronzing are sometimes used loosely to describe the same phenomenon.
|
|
|
|
|
Bloom
|
An undesirable cloudy effect or whitish powdery deposit on the surface of a plastic article caused by the exudation of a compounding ingredient such as a lubricant, stabilizer, pigment, plasticizer, etc. The term is also used to describe a discoloration of a metal mold.
|
|
|
|
|
Brightening
Agents
|
(optional brighteners, fluorescent bleaches, optical whitening agents) Chemical agents used to some extent in molded and extruded products, to overcome yellow casts and to enhance clarity or brightness. In contrast to bluing agents which remove yellow light, the optical brighteners absorb the invisible ultraviolet rays and convert their energy into visible blue-violet light. Thus, they cannot be used in compounds that also contain U.V. absorbing agents.
|
|
|
|
|
Brightness
|
The quality of color that is referred to as the sum of two scales ranging from black to white (lightness) and neutral gray to high chroma (saturation).
|
|
|
|
|
Bulk Molding
Compounds
|
(BMC) Thermosetting plastic resins mixed with stranded reinforcement, fillers, and other additives into a viscous compound for compression or injection molding.
|
|
|
|
|
CAB
|
Cellulose acetate butyrate is an automotive refinish coatings system.
|
|
|
|
|
Calcium
Carbonate
|
A filler used to extend a resin (calcite, chalk, limestone, whiting).
|
|
|
|
|
Carbon Black
|
Carbon black is a pigment made by the partial combustion and/or thermal cracking of natural gas, oil or another hydrocarbon.
|
|
|
|
|
Catalyst
|
A substance which causes or accelerates a chemical reaction when added to the reactants in a minor amount, without being permanently affected by the reaction. A negative catalyst (inhibitor, retarder) decreases the rate of reaction.
|
|
|
|
|
Cationic
|
Pertaining to any positively charged atom, radical or molecule; or to any compound or mixture containing positively charged groups.
|
|
|
|
|
Centipoise
|
A unit of viscosity, one hundredth of a Poise. At 20 degrees C, water has a viscosity of 1.00 centipoise.
|
|
|
|
|
Chemical
Resistance
|
The ability of a plastic to withstand exposure to acids, alkalis, solvents, and other chemicals.
|
|
|
|
|
Chroma
|
A term used in Munsell notation which deals with the psychological dimension of saturation.
|
|
|
|
|
Chromaticity
|
A dimension of color expressed in terms of hue and saturation.
|
|
|
|
|
Chromophore
|
A certain group of atoms which, when present in an organic molecule, give rise to color compounds.
|
|
|
|
|
Colloid
|
A substance capable of forming a suspension or emulsion with a liquid which will not settle out to a noticeable degree and will not readily diffuse. Colloidal particles usually have a high molecular weight.
|
|
|
|
|
Color
|
An aspect of appearance – the interaction of light, objects, and observers.
|
|
|
|
|
Color Constancy
|
The changes in the color of a single object as a function of the light source.
|
|
|
|
|
Color Difference
|
The degree or magnitude of difference between two objects under specified viewing conditions.
|
|
|
|
|
Color Match
|
Pairs of samples which exhibit no perceptible difference when observed under specified conditions.
|
|
|
|
|
Color Space
|
The three dimensional solid enclosing all possible colors.
|
|
|
|
|
Colorant
|
Unique chemical materials which absorb light an dreflect the complement.
|
|
|
|
|
Colorimeter
|
An instrument used to measure light reflected or transmitted by a specimen using three or four colored filter glasses. It is properly referred to as a tristimulus colorimeter.
|
|
|
|
|
Colorimetry
|
The science of color measurement.
|
|
|
|
|
Colorist
|
The term of European origin to describe a person skilled in the art of color matching and the behavior of colorants.
|
|
|
|
|
Complementary
Colors
|
Two colors which, when mixed together in proper proportions, result in a neutral color. Colored lights which are complementary mixed together form white light and follow the laws of additive color mixtures. Colorants which are complementary, mixed together, form black or gray and follow the laws of subtractive color mixtures.
|
|
|
|
|
Composite
|
A plastic composition in which fibrous reinforcements are imbedded, with strength properties greatly superior to those of the base resin. The reinforcements are usually fibers, rovings, fabrics or mats of glass, asbestos, metals, paper, sisal, cotton or nylon. Resins most commonly used are polyesters, phenolics, vinyl esters and epoxies.
|
|
|
|
|
Compression
Molding
|
A method of molding in which thematerial is placed in an open heated mold cavity, which is closed with a top force and pressure is applied to force the material into contact with all of the mold die areas. Heat and pressure are maintained until the molding material has cured.
|
|
|
|
|
Concrete Coatings
|
Protective and decorative coatings applied over concrete flooring.
|
|
|
|
|
Conditional Match
|
A pair of colors which appear to match only under limited conditions.
|
|
|
|
|
Copolymerization
|
The simultaneous polymerization of two or more monomers.
|
|
|
|
|
Cross-Linking
|
The setting up of chemical links between the molecular chains in polymer molecules. When extensive, as with most thermosetting resins, cross-linking makes one solid super-molecule of all the polymer chains. With thermosetting systems the cross-linking is not reversible.
|
|
|
|
|
Cryptometer
|
An instrument for measuring the opacity of surface coatings.
|
|
|
|
|
Density
|
Mass per unit volume of a substance expressed in units, such as grams per cubic centimeter, pounds per cubic foot or pounds per gallon. It is an important criterion in specifying plastics.
|
|
|
|
|
Differential Scanning Calorimeter
|
An instrument which measures the rate of heat evolution or absorption of a specimen while it is undergoing a programmed temperature change.
|
|
|
|
|
Dispersing Agents
|
Materials added to a suspending medium to promote and maintain the separation of discreet, fine particles of solids or liquids. They are used in the grinding of pigment powders.
|
|
|
|
|
Dispersion
|
A multi-phase system comprising of a finely divided material distributed in another material. Types of dispersions are emulsions (liquids in liquids), suspensions (solids in liquids), foams (gases in liquids), and aerosols (liquids in gases). In the plastics industry, the term dispersion usually denotes a finely divided solid dispersed in a liquid or in another solid. Examples are fillers and pigments in molding compounds.
|
|
|
|
|
Dominant
Wavelength
|
Wavelength of pure light which describes the region of minimum absorbency (maximum reflectance).
|
|
|
|
|
Dry Coloring
|
The process of adding colorants to molding compounds and resins in particulate form by tumble blending them with pigment or color concentrates.
|
|
|
|
|
Dye
|
A colorant which does not scatter light and is generally soluble in the medium used.
|
|
|
|
|
Elastomer
|
A material that at room temperature can be stretched repeatedly to at least twice its original length and upon immediate release of the stress will return with force to its approximate original length.
|
|
|
|
|
Emulsion
|
A two-phase, substantially permanent mixture of two completely miscible liquids, one of which is dispersed as finite globules in the other.
|
|
|
|
|
Encapsulation
|
The enclosure of adhesive particles within a protective film, sometimes called a binder, which prevents adhesive particle coalescence until such time as proper pressure or solvation is applied.
|
|
|
|
|
Endothermic
|
Pertains to a reaction which is accompanied by the absorption of heat, as opposed to exothermic liberation of heat.
|
|
|
|
|
Epoxy
|
A prefix denoting an oxygen atom joined to each of two other atoms which are already united in some fashion such as in –C-O-C. An epoxy resin is a family of thermosetting resins which contain a C-O-C ring (Epoxy group, oxirane group).
|
|
|
|
|
Equivalent
Weight
|
(combining weight) The atomic or formula weight of an element or ion divided by its valence. Elements entering into combination always do so in quantities proportional to their equivalent weights.
|
|
|
|
|
Ester
|
An organic compound corresponding in structure to a salt in inorganic chemistry. Esters are usually formed by the reaction of an organic acid to an organic alcohol. Water is usually a by-product of the reaction.
|
|
|
|
|
Exothermic
|
Pertaining to a reaction which is accompanied by the evolution of heat. An example in the plastics industry is the isocyanate-polyol reaction by which polyurethanes are made.
|
|
|
|
|
Extender
|
In plastics compounding, a substance added to the mixture to reduce its cost. The substance may be a resin, plasticizer or filler.
|
|
|
|
|
Filler
|
A relatively inert substance added to plastic compound to reduce its cost and/or to improve physical properties, particularly hardness, stiffness and impact strength. A filler differs from a reinforcement in two respects. Filler particles are generally small, and they do not markedly improve the tensile strength of a product, whereas reinforcements are fibrous and do markedly improve the tensile strength. The most commonly used general purpose fillers are clay, silicates, talcs, and carbonates. In some cases, a filler may be described as an extender.
|
|
|
|
|
Flame
Retardants
|
Chemical additives that reduce the tendency of materials to burn. They are usually incorporated during compounding, but sometimes are applied to surfaces of finished articles.
|
|
|
|
|
Flash
|
The thin, surplus web of material which is forced into crevices between mating mold surfaces during a molding operation and remains attached to the molded article.
|
|
|
|
|
Flash Point
|
The lowest temperature at which a combustible liquid will give off a flammable vapor that will burn momentarily.
|
|
|
|
|
Flexural
Modulus
|
(modulus of rupture) The maximum stress in the outer fiber at the moment of crack or break. This value is usually higher than the straight tensile strength.
|
|
|
|
|
Fluorescence
|
A phenomenon characterized by the reemission of absorbed radiant energy by certain chemicals or materials.
|
|
|
|
|
Free Radical
|
An atom or group of atoms having at least one unpaired electron. Most free radicals are short lived intermediates with high reactivity and energy. They play a role in many polymerization processes.
|
|
|
|
|
Fumed Silica
|
An exceptionally pure form of silicon dioxide. Individual particles of fumed silica, ranging from .007 to .05 micron, tend to link together to form chain like aggregates with high surface areas which retard the flow of liquids in which they are dispersed. This characteristic makes fumed silica useful as a viscosity control agent imparting thixotropy to liquid resins.
|
|
|
|
|
Gel
|
A jelly like substance formed by some type of chemical interaction.
|
|
|
|
|
Gel Coat
|
A thin outer layer of resin, sometimes containing pigment, applied to give the structure its surface gloss and finish. It also serves as a barrier to liquids and ultraviolet radiation. The gel coat is usually the first to be applied to the mold surface and becomes permanently bonded to the article through successive layers of reinforcement and resin.
|
|
|
|
|
Gloss
|
The subjective term used to describe the relative amount and nature of mirror-like (specular) reflection.
|
|
|
|
|
Glossmeter
|
An instrument for measuring the reflective properties of a surface.
|
|
|
|
|
Hazardous Air
Pollutants (HAPs)
|
Pollutants, also known as toxic air pollutants or air toxics, are air-borne substances that cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological effects. The EPA is required to control 188 hazardous pollutants. Examples of toxic air pollutants include benzene, which is found in gasoline; perchlorethlyene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries. **
|
|
|
|
|
Heat Stability
|
The resistance to change in color or other properties as a result of heat encountered by a plastic compound or article in either processing or end use. Such resistance may be enhanced by using a stabilizer
|
|
|
|
|
Hiding Power
|
The ability of a pigment to obscure the substrate.
|
|
|
|
|
Hue
|
The attribute of a color described by the names of red, yellow, green, blue, and purple.
|
|
|
|
|
Hydroxyl Value
|
A measure of hydroxyl (univalent OH) groups in an organic material. In urethane technology, hydroxyl number is an important factor in the selection of polyols to achieve desired characteristics of elastomers and foams.
|
|
|
|
|
Illuminants
|
Theoretical energy sources which can be described by specific spectral energy distributions.
|
|
|
|
|
Infrared Spectrophotometry
|
An instrumental technique used to identify organic substances in materials such as plastics.
|
|
|
|
|
Inhibitor
|
A substance which reduces or extends the chemical rate of reaction when added in small amounts to a molding compound.
|
|
|
|
|
Inorganic
Pigments
|
Pigments derived from naturally occurring minerals or synthesized from inorganic substances. They are always opaque as opposed to the more transparent organic pigments. Inorganic pigments are usually resistant to heat and light. Examples of those used in plastics are titanium dioxide, iron oxides, ultramarines, lead chromates, and cadmium compounds.
|
|
|
|
|
Krebs Unit
|
A measurement of viscosity used with reference to the Stormer Viscometer.
|
|
|
|
|
L*a*b*
|
L*a*b* are a specific set of color space coordinates which correspond approximately to equal visual perception in three dimensions where: L* - lightness (+) / darkness (-), a* - redness (+) / greenness (-), b* - yellowness (+) / blueness (-). The L*a*b* convention is specific to the CIE 1976 colormatching functions and are typically derived by mathematical expressions associated with color instrument measurements.
|
|
|
|
|
Laminar Flow
|
(lamular flow) The movement of one layer of fluid past another layer with no transfer of matter from one to the other.
|
|
|
|
|
Light
|
Visible energy in the range of 380nm to 770nm.
|
|
|
|
|
Light Source
|
A device which emits energy that is sensitive to the human eye, described by wavelengths between 380nm to 770nm.
|
|
|
|
|
LPA – Low
Profile Agent
|
A substance, usually a thermoplastic, that is added to a polyester compound in solution form that through differences in expansion properties will reduce the fiber prominence and surface waviness inherent to fiberglass reinforced polyester composites. Traditional LPA formulations do not pigment uniformly, but are required for the majority of automotive applications.
|
|
|
|
|
Masstone
|
A pigment/vehicle mixture which contains a single pigment.
|
|
|
|
|
Metamerism
|
Phenomenon where two objects appear to match under a specific set of viewing conditions and then cease to match when the viewing conditions change.
|
|
|
|
|
Molding
Compounds
|
A term applied to mixtures of polyester resin, filler, promoters/catalysts thickening agents, such as Plastigels and glass reinforcements. They may be identified by the nomenclature of BMC (bulk molding compounds) or SMC (sheet molding compounds).
|
|
|
|
|
Monochromatic
Light
|
Light energy at one specified wavelength.
|
|
|
|
|
Mottle
|
An irregular distribution or mixture of colorants or colored materials giving a distinct appearance of specks, spots, or streaks of color. Note: mottling may be purposely achieved for visual effect but it may occur accidentally due to improper mixing.
|
|
|
|
|
Nanometer
|
The unit of measurement used to describe wavelengths of light. One nanometer is equal to1 billionth of a meter or 10 angstroms.
|
|
|
|
|
Non-metameric
Match
|
Also called an invariant match. It is a condition in which two materials match under all viewing conditions.
|
|
|
|
|
Observer
|
A human viewer who receives the sensation of visible energy.
|
|
|
|
|
OEM Automotive
Plastics
|
Paints applied to automotive plastic component parts prior to assembly, parts such as instrument panels and side body moldings.
|
|
|
|
|
OEM General
Metal
|
Paints and coatings applied by the OEM to during the conversion process for coil stock or to finished goods such as appliances, metal furniture, fixtures, and other metal part.
|
|
|
|
|
Opacity
|
The term used to describe the degree to which a material obscures the substrate and blocks the passage of light.
|
|
|
|
|
Peroxides
|
An organic compound which contains at least one pair of oxygen atoms bonded by a single covalent bond. The peroxides most widely used in thermoset plastics are the reaction species which begin the gel process. They are described as catalysts.
|
|
|
|
|
Phthalate Esters
|
A critical type of chemistry to the thermoset industry. Phthalate Esters are produced by the direct action of alcohol on phthalic anhydride. The phthalates are the most widely used of all plasticizers.
|
|
|
|
|
Pigment
|
Finely ground, insoluble particles which, when dispersed in a liquid vehicle, provides color and many of the essential physical properties.
|
|
|
|
|
Polyester
|
A general term encompassing all polymers in which the main polymer backbones are formed by the esterification condensation of polyfunctional alcohols and acids.
|
|
|
|
|
Polymerization
|
A chemical reaction in which the molecules of a simple substance (monomer) are linked together to form large molecules whose molecular weight is a multiple of that of the monomer.
|
|
|
|
|
Primary Colors
|
Red, green, and blue hues defined by their spectrophotometric curves.
|
|
|
|
|
Pultrusion
|
A reinforced plastics technique for continuously producing constant cross-section profiles, both solid and tubular. Strands of reinforcing material are conveyed through a tank of resin, usually polyester or epoxy, from which they are pulled through an elongated, heated steel die shaped to impart the desired profile.
|
|
|
|
|
Reflectance
|
The quality of light energy returned to the observer from an opaque or translucent material
|
|
|
|
|
Saturation
|
The attribute of color perception which address the magnitude of departures from a grey color of equal lightness. Saturation may be described as color intensity when compared to another object of the same lightness.
|
|
|
|
|
Scattering
|
The diffusion or redirection of light energy encountering particles of different refractive indices. Scattering occurs at any such interface, at the surface or inside the medium containing particles.
|
|
|
|
|
Screen Process
Printing
|
A printing that employs a stencil of taut woven fabric secured in a from which marks the unaffected area inhibiting the ink to flow to the substrate. The stencil fabric is commonly called a "silk screen" even though silk is rarely used today. Nylon is most often used, and screens of copper, stainless steel and many other materials are suitable. The screen is placed above the part to be decorated, and a flexible squeegee forces ink through the openings in the screen onto the surface of the article.
|
|
|
|
|
Shear Rate
|
The overall velocity over the cross section of a channel by which molten or fluid layers glide to each other along the wall in laminar flow.
|
|
|
|
|
Sheet Molding
Compound
|
(SMC) A fiber glass reinforced thermosetting compound in continuous sheet form, usually rolled into coils interleaved with plastic film to prevent auto-adhesion. SMC can be molded into complex shapes with little scrap and is low in cost.
|
|
|
|
|
Specific Gravity
|
The ratio of weight of a given volume of a substance to that of an equal volume of water at the same temperature.
|
|
|
|
|
Spectrometer
|
An instrument which measures the response of material when radiated by electromagnetic energy (ie: infrared spectrometer).
|
|
|
|
|
Spectrophotometer
|
An instrument of measuring the transmittance and reflectance of specimens within various portions of spectrum. One useful application of this instrument is the formulation of colorants to match a given sample under all types of illumination. The instrument produces a curve representing the amounts of light energy the specimen will absorb over a wide range of wave lengths. Matching of the curve assures that the developed compound will look like the specimen under any lighting condition.
|
|
|
|
|
SPI
|
Abbreviation for Society of the Plastics Industry.
|
|
|
|
|
Stormer
Viscometer
|
An instrument consisting of a small paddle operated through a rotor which is actuated by the force of falling weights of various sizes.
|
|
|
|
|
Styrene
|
(vinyl benzene) A key raw material used to cross-link many polyester resins. It is a colorless liquid produced from ethylbenzene. Styrene monomer is polymerized by exposure to light, heat or a peroxide catalyst.
|
|
|
|
|
Subtractive Color
Mixture
|
The resulting spectral curve of two coloring materials. For example, the blending of a yellow pigment and a blue pigment results in a green specimen of decreased saturation.
|
|
|
|
|
Thermoplastic
Elastomers
|
A family of polymers that resemble elastomers because they can be repeatedly stretched without distortion of the unstressed part's shape, but are true thermoplastics and thus do not require curing or vulcanization as do rubber-like elastomers.
|
|
|
|
|
Thermoplastics
|
(Thermosets) Resins or plastic compounds which in their final state as finished articles are substantially infusible and insoluble. Thermosetting resins are often liquids at some stage in their manufacture or processing, and are cured by heat, catalysis or other chemical means. After being fully cured, thermosets cannot be resoftened by heat.
|
|
|
|
|
Thermosetting
Plastics
|
(thermosets) Resins or plastic compounds which in their final state as finished articles are substantially infusible and insoluble. Thermosetting resins are often liquids at some stage in their manufacture or processing, and are cured by heat, catalysis or other chemical means. After being fully cured, thermosets can not be resoftened by heat.
|
|
|
|
|
Tint
|
The term used to describe the mixture of a masstone with a white pigment.
|
|
|
|
|
Transmission
|
The quantity of light that goes through an object.
|
|
Truckbed Liners
|
An applied two-component urethane coatings offering protection and aesthetic value to pick-up truck beds.
|
|
|
|
|
Ultraviolet
Stabilizers
|
Exposure of many plastics to UV radiation, especially those in the near-violet region, can cause changes such as loss of gloss, crazing, chalking, discoloration, embrittlement, and electrical characteristics. Additives which protect plastics against such effects by preferentially absorbing the incident UV radiation and dissipating the associated energy in a harmless manner. They are sometimes described as ultraviolet absorbers.
|
|
|
|
|
Universal
Colorant
|
A colorant dispersion whose carrier vehicle has multiple applicability within their separate water/solvent or other generally defined categories.
|
|
|
|
|
Urethane
|
(Urethan, ethyl carbamate, ethyl urethane) A colorless crystalline substance used primarily in medicines, pesticides and fungicides. Urethane is not used in the production of urethane polymers or foams.
|
|
|
|
|
Urethane
Foams
|
(polyurethane foams, isocyanate foams) These foams differ from other members of the cellular plastics group in that the chemical reactions causing foaming occur simultaneously with the polymer forming reactions. As in the case of polyurethane resins, the polymeric constituents of urethane foams is made by reacting a polyol with an isocyanate. When the isocyanate is in excess of the amount that will react with the polyol, and when water is present, the excess isocyanate will react with water to produce carbon dioxide which expands the mixture.
|
|
|
|
|
UV – Ultraviolet Light
|
Emissions from a radiant source (usually the sun) that fall between 4 and 400 nanometers in wavelength. This is the more destructive radiation that occurs in natural sunlight and includes UVA and UVB radiation.
|
|
|
|
|
UVS
|
A Plasticolors proprietary product whereby pigments are dispersed directly into a blend of light stabilizers, surfactants, and antioxidants. These are designed to perform to specific customer weathering criteria. No host resin or carrier vehicle need be present in the dispersion.
|
|
|
|
|
Value, Color
|
Term to describe the lightness and darkness of an object.
|
|
|
|
|
Viscometer
|
(viscosimeter) An instrument used for measuring the viscosity and flow properties of fluids. A commonly used type (Brookfield) measures the force required to rotate a disc or hollow cup immersed in the specimen fluid at a predetermined speed. Of the many other types, some employ rising bubbles, falling or rolling balls, and cups with orifices through which the fluid flows by gravity. Instrument s for measuring flow properties of highly viscous fluids and molten polymers are more often called rheometers.
|
|
|
|
|
Viscosity
|
(dynamic viscosity) The tangential force or unit area of either of two parallel planes at unit distance apart when the space between the planes are filled with the fluid in question and one of the planes moves with unit differential velocity in its own plane. The unit for viscosity is the poise. The centipoises (0.01 poise) is also used.
|
|
|
|
|
Volatile Organic Compounds (VOCs)
|
Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen; these substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinners, degreasers, and dry cleaning fluids). *
|
|
|
|
|
Wavelength
|
The distance between two points of a periodic wave, as from crest to crest.
|
|
|
|
|
Weathering
|
A broad term encompassing exposure of plastics to solar or ultraviolet light, temperature, oxygen, humidity, rain, snow, wind, and air-borne biological and chemical agents.
|
|
|
|
|
White
|
Material that approaches total reflection of all visible light energy.
|
|
|
|
|
Yellowness
Index
|
A measure of the tendency of plastics to turn yellow upon long term exposure to light.
|
|
|
|
|
|