PET containers are produced from virgin material supplied by resin and polyester polymer manufacturers. There is one major manufacturer in South Africa, Hosaf Fibres. Hosaf was launched in 2001 and is a successor company to the polyester operation started by Hoechst. Production of virgin resin and polymers is done in Jacobs, south of Durban. In addition, Hosaf operates a fibre production plant in Cape Town and a PET recycling plant in Johannesburg.
Polyester resin manufacturers create PET from mono-ethylene glycol (MEG) and purified terephthalic acid (PTA). In common with all commodities used to make manmade fibres and plastics, MEG and PTA are derived from oil.
There are two key stages in PET manufacture: production of polymer chip in an amorphous state followed by solid state poly-condensation to raise its Intrinsic Viscosity (IV), thereby achieving the strength and resilience demanded in bottling applications.
The Jacobs operation comprises a continuous process (CP) plant – the only one in Africa – and two batch plants. The Jacobs CP plant was commissioned following Durban’s first full environmental impact study, an indication of the industry’s early adoption of sustainable environmental practice and willingness to engage local communities. Its production processes carry Federal Drug Administration (FDA) approval, a global quality benchmark in this field. Production quality also conforms to all relevant European Union directives as Hosaf complements production for South African customers with exports to overseas markets, primarily in Western Europe.
PET conversion has become a growth area for various companies, from small business to JSE-listed groups. Growth seems certain to continue as PET is being specified in an ever expanding range of bottling and packaging applications.
PET converters produce four principal types of product :
pre-forms (essentially, a bottle in embryo), single-stage bottles (pellet turned into a finished bottle in one process), two-stage bottles (pellet to pre-form which is then blown into a finished bottle) and multi-layer bottles (still relatively uncommon in South Africa, but essentially a bottle that makes use of different types of plastic). Converters may also make the closures (bottle tops) that ensure the integrity of a bottle’s contents.
The conversion process involves either stretch-blow moulding or injection-moulding.
Bottlers usually purchase pre-forms and then blow them into the finished bottle, before filling them up with the product that they manufacture.