Glossary
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Glossary |
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| additive: | any substance added to polymers to improve or modify one or more properties. | |
| antiblock: | an additive incorporated in or applied to plastic films to prevent the unintentional adherence during production, storage or use | |
| antioxidant: | an additive that inhibits or retards oxidation during production, processing, storage and use | |
| antistatic agent: | an additive which imparts a degree of electrical conductivity to plastics, allowing for the dissipation of static electricity. | |
| calcium carbonate: | widely used inorganic filler (calcite, chalk, marble and limestone) | |
| carbon black: | the most widely used black pigment, also acting as a UV stabiliser in plastics. | |
| carrier: | an inert polymer in which the active ingredients of a masterbatch are compounded | |
| chalking: | a dry, chalk-like appearance or deposit on the surface of a plastic | |
| clarifier: | an additive added to semi-crystalline polymers to modify their crystalline structure by providing sites for initiation of crystallisation, enhancing clarity, hardness, and tensile strength | |
| compatibility: | a state in which a component of an admixture in plastics will not exude, bloom, or separate | |
| compound: | the intimate admixing of a polymer or polymers with other ingredients such as fillers, plasticisers, catalysts and colorants | |
| copolymer: | a polymer derived from more than one species of monomer | |
| cross-linking: | the process of multiple intermolecular bonding between polymeric chains | |
| density: | weight per unit volume of a substance, usually reported in g/cc or kg/m³. | |
| die: | a steel block containing an orifice through which plastic material is extruded, thus shaping it to the desired form. | |
| discoloration: | a colour change which involves either lightening or darkening and/or change in hue | |
| dispersion: | a heterogeneous system in which a finely divided material is distributed homogeneously in an other material | |
| dye: | a colorant, usually transparent, which is soluble in the application medium | |
| extender: | an inert substance added to a polymer to reduce its cost | |
| extruder: | a machine for the continuous shaping of a moulding material through a die in the form of strands, films, fibres, pipes, sheets, profiles, etc. | |
| filler: | a solid, relatively inert, material added to a plastic in order to modify its strength, permanence, working properties, or other qualities or reduce their cost | |
| film: | a thin plane product of arbitrarily limited thickness, in which the thickness is very small in proportion to length and width | |
| flame retardant: | an additive which renders a polymer fire-resistant | |
| flexography: | a printing method in which a liquid ink is applied to a raised photopolymer or rubber plate (stereo) in contact with an inking (anilox) roller. the plate rotates and transfers the image to the surface of the substrate. | |
| fluorescent colorant: | a colorant that absorbs light as particular portions of the colour spectrum, re-emitting this light energy at much lower frequencies or longer wavelengths. | |
| gloss: | the degree to which a surface approaches perfect optical smoothness in its capacity to reflect light | |
| gravure printing: | a printing process by which the depressions in an engraved roll are filled with ink, the excess being wiped off by a doctor blade. ink remaining in the depressions is deposited on a flexible film as it passes between the engraved roll and the back-up roll | |
| haze: | a cloudy appearance within or on the surface of a plastic | |
| kLy: | kilo-Langley is a unit of incident radiation energy (1 kLy = 1 kcal cm-2) | |
| light fastness: | resistance to colour changes due to exposure to light without direct atmospheric effects | |
| lubricant: | an additive which facilitates processing or prevents sticking of a plastic formulation | |
| masterbatch: | a masterbatch is a concentrate of colorants or additives properly dispersed into a carrier polymer, which is then blended into the natural polymer to be coloured or modified | |
| MFI: | (melt flow index) the weight of polymer melt in grams forced through an orifice by a specified weight load in 10 min at a specified temperature. | |
| migration: | the transfer, usually undesirable, of a material from a plastic body to a contacting solid or liquid | |
| monomer: | a compound consisting of molecules each of which can provide one or more constitutional units | |
| opacity: | the property of an object to obstruct the penetration of light | |
| pellet: | a granule of a preformed moulding material having relatively uniform dimensions in a given lot, used as a feedstock in moulding and extrusion operations | |
| pigment: | substance consisting of particles that are practically insoluble in the application medium, used chiefly as a colouring material. | |
| plastic: | a material containing a high polymer as an essential ingredient and which at some stage in its processing into a finished product can be shaped by flow | |
| plasticiser: | a substance of low or negligible volatility incorporated in a plastic to lower its softening range and to increase its workability, flexibility or extensibility | |
| plate out: | the undesirable deposition of additives or pigments on machinery during processing of plastics. | |
| polymer: | a substance composed of molecules characterised by the multiple repetition of one or more species of constitutional units (monomers) linked with each other in such amounts that provide a set of properties that do not vary markedly with the addition or rem | |
| polyolefins: | the class of polymers made by polymerising relatively simple olefins | |
| polypropylene: | a tough, lightweight, rigid plastic made by the polymerisation of propylene gas | |
| premix: | an admixture of resin and additives in powder form, usually prepared by the processor shortly before use | |
| reducer: | a liquid system whose sole function is to reduce solids concentration, viscosity and colour strength of an ink or paint system | |
| resin: | any polymer which may be incorporated in a plastic material, ink or paint system | |
| rigidity: | the property of materials to withstand failure in extensional, impact or flexural stress | |
| slip additive: | a substance which tends to make surfaces slippery i.e. reduce the coefficient of friction. | |
| solvent: | the liquid carrier of an ink or paint systems where resins and additives are dissolved and/or suspended | |
| solvent retention: | incomplete evaporation of the volatile fraction of an ink or paint system during application | |
| stabiliser: | a substance used in the formulation of plastics to assist in maintaining the properties of the material at or near their initial values during processing and service life | |
| suspension: | a dispersion of a solid into a liquid | |
| titanium dioxide: | a white pigment available in two crystalline forms, rutile and anatase, the former being the most widely used white and opacifying pigment in thermoplastics, printing inks and paints. | |
| UV absorber: | an additive which protects materials by absorbing UV radiation. | |
| UV stabiliser: | additive which stabilises organic materials against UV radiation. | |
| varnish: | a liquid system whose sole function is to reduce pigment concentration in an ink or paint system | |
| warpage: | dimensional distortion of a plastic object after moulding or other fabrication | |
| weathering: | the process of material ageing (usually degradation) due to direct outdoor exposure | |