PET is an acronym for Polyethylene terephthalate, a plastic material which is part of the polyester family and can be used for food contact applications. PET is perfectly transparent, light, shock-resistant and can be produced in different colours. The production of bioriented bottles in PET occurs in two phases:
- The first phase consists in creating a preform by injection mold of melted PET at 350°C in appropriate moulds with particular characteristics in terms of shape and thickness depending on the type of final bottle.
- The second phase entails blowing of the preform, at a temperature of 120°C, with a simultaneous axial and radial stretch.
The stretching confers to the bottle a bioriented structure, improving its mechanical resistance and gas barrier properties.
The use of PET bottles started to become widespread within the beverage industry in the late 70’s. PET use started in the mineral water sector and the CSD and then expanded in the juices, fresh milk, wine and liqueurs market. PET has recently entered in the beer sector, thanks to new systems for coating of the bottles to increase barrier properties against oxygen and carbon dioxide.
Additionally, there is a current study in process concerning additives which, if added to liquid PET prior to injection in the preform moulds, confer improved UV or oxygen barrier properties to the material.
PET containers have many advantages, such as a high shock-resistance, great transparency, lightness, the possibility of producing tailor-made bottles with original shapes and a good barrier against carbon dioxide.
Today PET can be easily recycled, with systems now able to recycle the product to produce new bottles using 100% of material coming from old bottles. The compatibility of PET for food contact is sanctioned by norms 2002/72/CE of the European commission and subsequent modifications (2004/19/CE).