PET Plastic- Common Questions Answered

PET

WHAT IS PET?

Polyethylene terephthalate otherwise known as PET is the most common thermoplastic polymer resin of the polyester family. It is used for fibers, clothing, containers, liquids, packaging and engineering resins.

Polyester is a category of polymers that contains the ester functional group; ester are chemical compounds derived from an acid which at least one hydroxyl group is replaced by an alkoxy group.

In the textile world polyester is the common name for PET whereas in the packaging world the acronym PET is generally used.

Depending on how it is processed polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer.

 

WHAT IS PET MADE FROM?

Polyethylene terephthalate is produced either from the transesterification reaction of ethylene glycol and dimethyl terephthalate or the esterfication reaction of ethylene glycol and terephthalic acid.

 

HISTORY OF PET?

Polyester was first developed for fibers for the textile industry in 1941.

In the mid 1960’s polyethylene terephthalate was used for food packaging.

Nathaniel Wyeth patented the PET bottle in 1973.

1977 the first PET bottle was recycled.

1982 the first manufacturer of polyethylene terephthalate in South Africa was started by SANS.

 

WHAT ARE COMMON PET PROPERTIES?

PET is known for being lightweight, transparent, strong, rigid and shatter resistant. It is thermostable, BPA (bisphenol A) free which means it is safe for food containers and packaging. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol and solvents.

Polyester fiber is light, resistant to light and climatic conditions, crease-resistant, quick drying and strong. It is used for apparel, insulation, textiles, automotive and geotextiles. Even sails for sailing boats are made from polyester however spinnakers are usually made from nylon.

It is 100% recyclable.

 

WHAT IS PET RECYCLED INTO?

Recycled polyethylene terephthalate is called rPET. In 2013 South Africa recycled 48% of all PET bottled manufactured and is estimated to reach 70% by 2020.

It is also recycled into: fibers for polyester carpeting, pillows, duvets, t-shirts, underwear, shoes, sweaters, luggage, upholstery, strapping, chocolate trays, bottles, food packaging.

 

CAN PET BOTTLES BE REUSED?

PET bottles are FDA (and other world-health safety agencies) approved for continual reuse. Polyethylene terephthalate is a stable, inert material that doesn’t biologically or chemically degrade with use and is resistant to attack by micro-organisms. Regulatory authorities have tested PET bottles and found no harmful substances in either new or re-used bottles.

HOW ARE PET BOTTLES MOULDED?

Polyethylene terephthalate bottles are generally created in a two steps process. First by injection moulding performs which are in the shape of a test tubes. These performs are then blow moulded into the desired shape. In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for moulding non-standard shapes including jars, flat oval, flask shapes, etc.