Beverage multinational subsidiary Coca-Cola Bottling South Africa (CCBSA) uses 10% recycled polyethylene terephthalate (rPET) and has completed technical and production validation of 25% rPET content, but is constrained by the availability of rPET, Coca-Cola Bottling Gauteng and inland regional supply chain manager Henry Peek said on Friday.
CCBSA energy and sustainability manager JP Blumenthal detailed the company's engineering work to make their PET beverage bottles lighter, called lightweighting, which has seen the weight decrease from 54 g for a 2 litre bottle about 11 years ago to 45.7 g currently, with a wall thickness of about 0.3 mm. The company has validated further lightweighting and can reduce the weight of a 2 litre bottle to 41.8 g, which it would phase in over the next six months.
Ongoing research and development work mainly involves testing the effectiveness of thinner bottles to contain carbon dioxide (CO2) for the carbonated beverages' shelf life, which is currently at about 14 weeks. This does not include the food safety of the product, as canned carbonated beverages can last up to two years because they do not lose CO2.
Blumenthal and his team have worked on ensuring that the stretching of the bottles in the bottle blowers, which expand the small preform PET bottles at a temperature of 130 °C to 140 °C into the sizes required, maintains the performance of the bottles at the same level as the thicker bottles. He said the barrier properties of thinner PET bottles can ensure customer experience remains the same as controlled stretching of the polymer aligns the molecular orientation and structure of the plastic, enabling it to contain the CO2.
A lower weight also directly contributes to reduced energy consumption in the ovens to heat the bottles before they are expanded and the company has reduced energy use in its ovens by 18% to 19% through the use of fast reheat additives and expects to reduce the energy consumption by a further 10% by early next year.
It is performing commercial trials, Peek said.
The company aims to increase the rPET content of its plastic bottles to 13%. It is trying to stockpile rPET to be able to do this, and it can increase the rPET content to 25%, if sufficient recycled materials are available.
During a tour of recycling company Mpact's R350-million plant polymer recycling plant on Friday, which supplies some of the rPET used by CCBSA, Mpact Polymers GM Nicholas Schild pointed out that South Africa recycles about 65% of its PET bottles, according to industry body PETco, but that about 80% to 90% of its PET feedstock is still sourced from landfill sites across the country.
The company also directly supports the establishment and expansion of small recycling businesses across the country, providing technical training, assistance and baling machines for local recycling companies. Local businesses are critical for effective collection, especially in South Africa, Schild said.