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Applications : bulletproof windows, break resistant lenses, compact discs, Riot
shields, optical lenses and headlamp sets, medical items, safety helmets and
glasses, machine guards and power tool housings, laboratory, vacuum desiccators
and centrifuge tubes, cores for solenoids, baby bottles, lighters, hairdryers, coffee
machines, CD ROM's, DVD's, connector housings, switch boxes.
27) Polyethylene Terephthalate (PET):
PET is very light weight polymer with its crystallinity varying from amorphous to
fairly high crystalline and can be semi-rigid to rigid depending on its thickness. It is
naturally colorless with a high transparency but thicker sections are usually opaque
and off-white.
Density 1.3 - 1.4 g/cm 3
Glass transition temperature 73 - 78 °C
Max /Min. continuous Service temperature 80 - 140 °C / -40 °C
Melting Temperature 250 °C
Absorbs moisture hence pre drying before processing is highly recommended for 2-
4 hours at 120°C.
PET can be Injection moulded, Thermoformed, Extruded and Blow moulded.
For Injection Moulding melt temperature of 280-310°C is recommended. Mould
temperature of 140-160°C to obtain a crystalline PET and between 10 and 50°C for
transparent applications is recommended.
In Extrusions with melt temperature of 270-290°C generally films and sheets are
produced (can be thermoformed later)
Blow moulding is generally used to produce transparent bottles with mould
temperature recommended between 10 and 50°C.
Strengths: excellent wear resistance and electrical properties, low coefficient of
friction, high flexural modulus, and superior dimensional stability, broad range of
use temperature, low gases permeability in particularly with carbon dioxide, FDA
compliant , Transparent to microwave radiation, higher strength & stiffness than
PBT. PET exhibits highest HDT and long-term use temperature among general-
purpose engineering thermoplastics. Because PET has no centreline porosity, the
possibility of fluid absorption and leakage is virtually eliminated.
Limitations: PET is notch sensitive, and is not recommended for outdoor use or in
hot water, poor burning behaviour, Lower mouldability than PBT, due its slow
crystallization rate.
Applications: Mineral-water and Soft-drinks bottles, cosmetic jars, microwavable
containers, transparent films, electrical plugs and sockets, appliances Housings,
MPET (metalized PET) for flexible food packaging and thermal insulation, magnetic
tape, backing for pressure sensitive adhesive tapes, packaging trays and blisters,
thermoformed food containers, signs and displays boards, disposable glasses and
coffee cups.
28) Polybutylene Terephthalate (PBT):
Is semi-crystalline polyester. It is an engineering plastic with high stiffness and
strength with very low moisture absorption (an important difference with
polyamides).

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