“Contamination is removed during the process through a combination of monomer and polymer filtration units and by vacuum extraction which runs for several hours at temperatures between 270-300°C.”
Plastic films producer DuPont Teijin Films has claimed to have made a “significant step forward” in developing a chemical recycling process for PET plastic. Earlier this week, the company announced details of its LuxCR depolymerisation process, which can be used to produce biaxially-oriented polyethylene terephthalate (BoPET) films.
In a statement, DuPont said that BoPET films could be used in a variety of applications and markets, including food packaging.
Currently, most PET plastic is mechanically recycled, involving expensive machinery to sort, shred and wash the plastic. This often works well, but to recycle PET to make new food packaging you can only use existing food-grade plastic. Chemical recycling is when a chemical process is used to turn plastics like PET into new products. In relation to mechanical recycling, certain end-use applications are temperature restricted, DuPont said.
DuPont (@DuPont_News)also said that although mechanical recycling “will continue to play an important role in the circular economy”, there were some “limitations” with regards to the physical and mechanical properties of the recycled product over repeated cycles.
In a statement, DuPont said: “The LuxCR process addresses these two issues by depolymerising mechanically recovered PET flake back into the monomer unit bis (2-hydroxyethylterephthalate) or BHET which is chemically indistinguishable from virgin monomer.
“This base monomer is then repolymerised into a polyester polymer which is subsequently converted into a wide range of BoPET films. Contamination is removed during the process through a combination of monomer and polymer filtration units and by vacuum extraction which runs for several hours at temperatures between 270-300°C.”
According to DuPont, although the initial focus for the LuxCR process is to provide a feedstock to DuPont Teijin Films’ own manufacturing lines, feasibility studies are underway to see if the scope can be extended to include the external sale of polymer which would open up the technology to applications such as PET bottles and trays.
The chemicals sector has been pressing ahead with chemical recycling to meet its circular economy aims. Currently, there is a big focus on using renewables instead of fossil sources and using recycled material instead of virgin fossil material.
Separately, speaking to Bio Market Insights in January, Dr. Christian Krueger, corporate sustainability strategy expert at chemicals giant BASF, said that BASF was already evaluating chemical recycling to use plastic waste as feedstock to produce new chemicals. However, he also stated that this was not yet recognised as a contribution to fulfilling recycling quotas.
He added: “We also need a market environment, so that our customers can be more successful with sustainable products. In the packaging industry, customers are already demanding solutions which are recyclable or are of renewable origin.
“The biggest hurdle is often the price and performance of the product. Therefore, BASF has developed its biomass balance approach, where products made from renewable resources exhibit the same performance as its counterparts made from fossil feedstock. The availability of sustainable bio-based feedstock is still a challenge. We need more investment in new technologies to convert waste or residues to chemicals.”
You may also be interested in reading…