All
| Term | Definition |
|---|---|
| Epoxy Resins |
Thermosetting resins which, in the uncured form, contain one or more reactive epoxide or oxirane groups. These groups serve as crosslinking points in the subsequent curing hardener. Epoxy resins are used in protective coatings, bonding adhesives, in building and construction, and electrical uses. |
| Erucamide |
A fatty acid-based slip additive used in polyolefin resins. |
| Ethylene |
A colorless, flammable gas derived by cracking of petroleum and natural gas fractions. Also serves as a monomer for polyethylene. |
| Ethylene Vinyl Acetate (Eva) |
Copolymeric member of the polyolefin family derived from random copolymerization of vinyl acetate and ethylene. |
| Exotherm |
The temperature vs. time curve of a chemical reaction and the amount of heat given off. Maximum temperature occurs at peak exotherm. |
| Exothermic Reaction |
A reaction in which heat is given off. |
| Extensibility |
The ability of a material to extend or elongate upon application of sufficient force, expressed as a percent of the original length. |
| Extrudate |
The film, wire coating, pipe or other product of the extrusion process. |
| Extrudate Swell |
See Die Swell. |
| Extrudate Swell Ratio |
See Die Swell Ratio |
| Extruder |
A machine for producing more or less continuous lengths of plastic sections such as rods, sheets, tubes, profiles, and cable coatings by melting and pumping resin through a forming die. |
| Extruder Size |
The nominal inside diameter of the extruder barrel. |
| Extruder, Compounding |
The basic functions of a compounding extruder are to melt the polymer and evenly disperse and distribute additives or fillers to meet the specifications of the end product. Large-scale compounding is done on either single-or twin-screw extruders. Single screws are used for basic operations where little variation in material formulation and viscosity is expected. Twin-screw compounders offer better mixing characteristics. |
| Extruder, Single Screw |
Basic machine consists of a screw, barrel, drive mechanism, resin feed arrangement and controls. The constantly turning screw augers the resin through the heated barrel where it is heated to proper temperature and blended into a homogeneous melt. Before the melt can leave the barrel, it must pass through a breaker plate and screen pack. The melt is then extruded through the die into the desire shape. |
| Extruder, Twin Screw |
Two screws, side by side, are placed within the extruder barrel, either co-rotating twin screw extruders are used primarily for processing PVC products such as pipe, siding, sheet, pellets, and film. The co-rotating units are used for compounding materials where thorough mixing and high output rates are important. The twin-screw unit resembles a positive displacement screw pump. It coveys the material at low speeds with controlled shear. The positive action assures that all portions of the material experience a uniform residence time. |
| Extruder, Vented |
An extruder provided with a vent hole, usually in the metering zone where the material has attained a molten condition, for the withdrawal of gases and air. |
| Extrusion |
Compacting and melting a plastic material and forcing it through an orifice in a continuous fashion. In the extrusion process, the material is conveyed through the heated machine barrel by a helical screw where it is heated and mixed to a homogeneous state and then forced through a die of the shape required for the finished product. |
| Extrusion Blow Molding |
Extruder is operated continuously and the output either feeds an accumulator or flows through the die as an endless parison, pinching it off, with air then introduced into the cavity. |
| Extrusion Plastometer |
A type of viscometer used for determining flow rates of a polymer under specified temperatures and loads, more commonly known as a melt indexer. |
| Exudation |
Migration of additives from the interior to the surface of a plastic part to the melting zone. |
| Fan Gate |
Opening between the runner and the cavity which has the shape of a fan. This shape reduces stress concentrations in the gate area by spreading the opening over a wider area. |
| Fatigue Strength |
The maximum cyclic stress a material can withstand for a given number of cycles before failure occurs. |
| Feed Section |
First section or zone of an extruder screw, which is fed from the hopper and conveys solids. |
| Filament |
Fiber of extreme length, used in yarns and other compositions. |
| Fill |
In injection molding, packing of a cavity or cavities to produce complete parts. |
| Filler |
A material which is added to plastics to make it less costly. Filler can be inert or can alter various properties of the plastic. |
| Film |
Sheet material having a nominal thickness not greater than 10 mil. |
| Fisheye |
Small globular mass which has not blended completely into the surrounding material resulting as a fault in film or sheet. |
| Flame Retardant |
Reactive compounds and additive compounds to render a polymer fire resistant. Reactive compounds become an integral part of the polymer. |
| Flame Treating |
A method of rendering the surface of inert thermoplastics or other substitutes, particularly polyolefins, receptive to inks, lacquers, paints, adhesives, and the like by bathing the surface of the article in a highly oxidizing flame. This treatment oxidizes the surface layer of the article, making it receptive to coating. |
| Flammability |
The measure of the extent to which a material will support combustion. The test usually used is described in ASTM D-1433, the results being expressed in seconds required for specimen to burn over six inches of its length. |
| Flash |
The thin, surplus web of material which is forced into crevices between mating mold surfaces during a molding operation, and which remains attached to the molded article. It is usually removed by deflashing operations such buffing, grinding, tumbling, or blasting. |
| Flash Gate |
A long, shallow rectangular gate in an injection mold. |
| Flash Mold |
A mold designed to permit excess molding material. |
| Flexural Modulus |
Ratio of applied stress to strain in outer fibers of a plastic specimen during flexure. |