POLYESTER (PBT & PET)

Polyesters are engineering thermoplastics based on Polybutylene Terephthalate (PBT) and Polyethylene Terephthalate (PET).  They combine excellent mechanical, electrical and thermal properties with very good chemical resistance and dimensional stability.

Please Note: This page is for information purposes only. Rutland Plastics is an Injection Moulder and does not supply polymers.

PROPERTIES

Polyesters have high hardness and good impact strength.  Together with excellent dimensional stability (due to low water absorption compared with Nylons, for example) they also provide high heat resistance.  The materials have both good chemical and weathering resistance.

COLOURING

The natural colour of the material is transparent so it is available in a wide range of colours and can be easily self-coloured using masterbatch.  There is now a wide range of masterbatches specific for use with PET.

Finishing

The material can be machined on conventional lathes using standard metal machining tools.  Can be glued using adhesives.  Can be decorated by all known printing systems but due to the chemical resistance of the material it is difficult for inks to adhere so a primer should be used.  Parts can readily be painted.  Vacuum metallization is the best method for plating.  Parts can be vibration, spin, hot-plate and ultrasonically welded.

CHEMICAL RESISTANCE

Mineral Acids (dilute)Excellent
Mineral Acids (concentrated)Poor
AlkaliFair
AlcoholExcellent
KetoneFair
Aromatic HydrocarbonFair
Chlorinated HydrocarbonFair
DetergentsGood
Oils, GreasesExcellent

PBT & PET USE

PET
Carbonated Soft Drink Bottles49.0%
Mineral Water Bottles29.2%
PET Sheet11.7%
Beer/Wine/Spirit Bottles6.1%
Other 13.1%
PBT
Electric/Electronic38.7%
Automotive22.5%
Household Appliances7.3%
Other31.6%

APPLICATIONS

The main application for PET is in the manufacture of blow moulded bottles.  PBT is used for high quality and high stress engineering components such as automotive windscreen wiper arms, door handles and particularly electronic parts; household appliances and in electric and electronic engineering, for example circuit breakers.