18. Jun 2024
Innovative flexible plastic film material based on PLA
A team from the Fraunhofer Institute for Applied Polymer Research IAP has now developed a flexible and recyclable plastic film material based on polylactide (PLA) bioplastic and paved the way for its commercialization. For their efforts, they will receive the Joseph von Fraunhofer Prize for 2024.
Due to its high stiffness, PLA is perfectly suited for rigid packaging such as disposable cups – but not for flexible disposable packaging such as shopping bags, which are one of the main sources of disposable plastic waste. Antje Lieske has solved this problem together with her colleagues André Gomoll and Benjamín Rodríguez at Fraunhofer IAP.
“We coupled plasticizers, so-called polyethers, directly with the polymer chain to make the material more flexible over the long term. Polyethers are non-toxic, commercially available and can also be produced from bio-based raw materials. Until now, plasticizers have been mixed into PLA as additives. However, the plasticizer molecules migrate out of the material over time, making the PLA stiff and rigid again. To prevent this migration, we anchored the polyether to the polymer. To achieve this, we synthesized PLA-based block copolymers in which the polyether chain segment is covalently linked to PLA chain segments at both ends”, explains Benjamín Rodríguez.
Sustainable and flexible plastic with great potential
The result is a novel, flexible PLA material that does not contain migrating plasticizers and, unlike LDPE, is at least 80 percent biobased. “In the long term, we might be able to increase this proportion to almost 100 %”, Gomoll explains. “In addition, our material can be produced cost-efficiently from commercially available raw materials in a simple synthesis process. This process does not require large-volume synthesis plants but can be implemented locally by medium-sized companies as a continuously operated process. Until now, PLA could only be produced profitably in continuous large-scale plants, which excluded smaller companies as manufacturers. Finally, the new PLA material can also be processed into plastic films using conventional processing equipment in a similar way to LDPE – and it can be chemically recycled with considerably less energy input than LDPE”, Gomoll continues.
These unique material properties prompted the Polymer-Group company to commercialize the material. In 2023, SoBiCo GmbH, a subsidiary of the Polymer-Group, commissioned a production plant for the new PLA block copolymers in Pferdsfeld (western Germany). It produces 2,000 tonnes of the new bioplastics per year under the name Plactid®. In the long term, it is set to produce 10,000 tonnes of the new flexible PLA material each year.
The new class of bioplastics will make an important contribution to making plastic packaging materials more sustainable. In addition to flexible packaging films, the new material might also tap into completely new use cases, e.g., in the automotive sector, in the textile industry and in additive manufacturing.
Read more in the complete press release
Picture: The new PLA material can be processed into plastic films in a similar way to LDPE using conventional processing plants. (photo: © Piotr Banczerowski)