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Common Thermoplastics Defined


  1. Polyethylene Terephthalate (PET). PET is clear, tough and has good gas and moisture barrier properties. Some of this plastic is used in PET soft drink bottles and other blow molded containers, although sheet applications are increasing. Cleaned, recycled PET flakes and pellets are in great demand for spinning fiber for carpet yarns and producing fiberfill and geotextiles. Other applications include strapping, molding compounds and both food and non-food containers. Introduced in the 1970s.

  2. High-Density Polyethylene (HDPE). HDPE is very tough, chemically resistant thermoplastic, with a "soapy" touch; e.g., used for blow-molded parts such as fuel tanks or other moldings, such as bumpers. Is has excellent resistance to most household chemicals, does not absorb moisture, and makes a good water vapor barrier. Invented in 1957.

  3. Polyvinyl Chloride (PVC). PVC is a thermoplastic made from sodium chloride (salt) salt and ethane (natural gas). It is a non-toxic, odourless, flame resistant, bio-stable and chemically resistant white powder which, when mixed with different additives and treated in various production processes, can be formed into a large number of plastic products. The term PVC is also generically used to describe products made of PVC (for example PVC flooring, PVC gloves, etc.) Invented in 1927.

  4. Low-Density Polyethylene (LDPE). LDPE is lightweight, thermoplastic that feels waxy; is resistant to chemicals and moisture and flexible enough to squeeze. Won't stiffen or become brittle from cold; resistant to chipping, crushing and peeling, but will not last with abrasive cleaning or sterilizing. Desirable properties include clarity, sealability, chemical inertness and ease of processing. Invented in the 1940s.

  5. Polypropylene (PP). Polypropylene has excellent chemical resistance, is strong and has the lowest density of the plastics used in packaging. It has a high melting point, making it ideal for hot-fill liquids. In film form it may or may not be oriented (stretched). PP is found in everything from flexible and rigid packaging to fibers and large molded parts for automotive and consumer products. Invented in 1957.

  6. Polystyrene (PS). Polystyrene is a very versatile plastic that can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It has a relatively low melting point. Typical applications include protective packaging, containers, lids, cups, bottles, trays and tumblers. Available as a crystal or a toughened blend with elastomers for elasticity. Invented in 1938.

  7. Polycarbonate (PC). Polycarbonate is a thermoplastic polymer resin that is linear polyester of carbonic acid. Polycarbonate is a transparent, nontoxic, non-corrosive, heat resistant, high impact strength plastic; it is generally stable, but may be subject to attack by strong alkalis and some organic hydrocarbons. It can be molded, extruded, or thermoformed, and is commonly used for numerous applications, such as non-breakable windows, household appliances, tubing, piping, and cartridge filter sumps. Invented in 1957.

  8. Acrylonitrile-Butadiene-Styrene(ABS). ABS is a thermoplastic derived from acrylonitrile, butadiene, and styrene, the strongest of the styrene copolymers and the most widely used. Typical applications are found in appliances, automotive parts, pipe, business machine and telephone components. Invented in 1948.

  9. Nylon (PA). Nylon is a polyamide fiber derived from coal, water and air. Introduced in 1938, nylon is the first and oldest of the true synthetics. Famous for its strength, abrasion resistance, dimensional stability, soft hand, elasticity, easy-washing qualities and quick-drying characteristics. Invented in 1938.

This technical information has been contributed by
Valley Extrusions

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