Glossary Terms

Antistatic - Preventing or inhibiting the build-up of static electricity.

Barrier - Impermeable to the liquid or gas phases of most chemicals and reagents.

Batch Reaction - Production of a substance resulting from one operation.

Biaxially-Oriented - Polymer molecules are drawn or stretched in both the machine and cross machine direction to achieve maximum strength.

BOPET - Biaxially-oriented PET film.

Casting Drum - Rotating drum that collects the flat sheet of molten polymer as it exits the die and cools film to below the melting point.

Chemical Resistance - Ability of a polymer to withstand cracking, crazing, swelling, or dissolving when in contact with organic fluids or hydrocarbon greases.

Clips - Devices assembled into a chain to grip the edges of a web and carry the web through a tenter.

Coating - A thin polymeric layer applied to the surface of a film to provide enhanced surface characteristics.

Coefficient Of Friction (COF) - The ratio of the static or kinetic friction force to the normal force.

Coextrusion - Mixing molten streams of different polymers from a like number of extruders in a multi-manifold die to produce multi-layer films.

Condensation - During polymerization, monomers react to release a small molecule such as water.

Continuous Process - An uninterrupted sequence of operations, i.e., the melt extrusion process is continuous.

Copolymer - Simultaneous polymerization of two or more different monomers to form a polymer.

Corona Treating - The act of exposing the surface of a material to a highly active electric field to modify its surface energy.

Crystallization - Process by which a polymer can form a geometrically regular (ordered) structure to produce a more stress resistant, dimensionally stable polymer that its non-crystalline counterpart.

De-Polymerization - The decomposition of some polymers by stepwise loss of monomer units in a reaction, i.e. reverse of polymerization.

Dimensional Stability - The physical properties of a material which describe its dimensional response to heat or moisture.

Edge Trim - 1) That portion of a web which is removed due to its use as the gripped area during tentering;
2) That portion of a web which is removed to produce the customer desired width.

Esterification - The reaction of an acid with an alcohol to form an ester.

Extrusion - Process by which polymer is propelled continuously along a screw through regions of high temperature and pressure where it is melted and compacted, and finally forced through a die (slit) to form a thin film.

Fast Nip Rolls - Rolls which nip a web to a fast moving roll set to produce stress for stretching the web.

Flatness - That property of a web which describes its ability to maintain a planar shape under no stress.

Forward Draw (MDO)- A mechanical assembly of heated rolls, cooled rolls and auxiliary heaters for the purpose of stretching a material in the machine direction.

Heat Sealability - Ability of a polymer to seal to itself or to other polymeric substrates when heat and pressure are applied.

Heavy Metals - High specific-gravity elements, such as arsenic, barium, cadmium, chromium (+6), lead, mercury, nickel, selenium, and silver, used in coatings, paints, lacquers in packaging applications, children's toys, furniture, and other industrial uses. The EPA and other environmental groups are evaluating these metals for potential toxic effects in humans.

Lamination - Process by which a sandwich of film layers are bound together by adhesives, coatings, or other polymers to form substrates with improved physical and chemical properties.

Master Roll - The first assembly of a web into a wound roll after manufacture.

Monomer - A starting material from which the polymer is formed.

PEN - Poly(ethylene naphthalate), a linear polyester.

Permeability - The ability of small molecules to diffuse slowly through a polymeric membrane.

PET - Poly(ethylene terephthalate), a linear polyester.

PETF - PET film.

Plasticizers - Liquid additives, such as phthalate esters, used to soften rigid polymers.

Polyester - A condensation polymer formed by the reaction of a dicarboxylic acid (or its methyl ester) with a diol followed by the elimination of H2O (or methanol).

Polymer - A large molecule built up by the repetition of small, simple chemical units high molecular-weight substance (from 10.000 to >20,000) formed in an association reaction in which many molecules come together to form one large molecule.

Polymerization - Reaction of two molecules to form a polymer; the length of the polymer chain is specified by the number of repeat units in the chain (degree of polymerization).

Post-Consumer Recycle (PCR) - Material that is recycled from plastic constructions, i.e. bottles, packaging, collected from consumer waste streams.

Reagent - Any substance used in a chemical reaction to detect, measure, examine, or produce other substances.

Shrinkage - The degree to which a polymer constricts when exposed to heat.

Slip - The property of a material to slide against either a similar or different material as measured by its coefficient of friction against that material.

TDO - The portion of a tenter designed to stretch a material in the transverse direction.

Tensile Modulus - The measure of the initial resistance of a material to longitudinal stretching.

Tensile Strength - The load required to break a material by longitudinal stretching.

Stenter (Tenter) - A device for gripping the edges of a moving web to support the web during heating and stretching operations.

Thermal Stability - Ability of a polymer to maintain its physical properties when exposed to high temperatures.