Completely Novel Possibilities
With the VINNEX® range, WACKER experts have made it possible to manufacture containers for hot-filling applications from PLA/PBS blends by thermoforming. This could make the binder a valuable raw material for coffee mugs and soup containers in the future. Most VINNEX® grades are suitable for use in food-contact applications.
The binder additive opens up entirely new possibilities for bioplastics. Take polylacticacid as an example. Even though PLA is a very rigid material, the addition of 20 to 30 percent VINNEX® enables very thin and highly transparent sheets to be made without any trouble. These sheets exhibit reduced noise levels and are considerably easier to weld, which makes them ideal for display and shrink films for the food sector, for example. Since VINNEX® significantly improves the adhesion of PLA to paper, new possibilities also open up for high-speed extrusion coating, e.g. for coated paper cups and storage trays.
Products Remain Biologically Degradable
Furthermore, VINNEX® expands the application range of polyhydroxyalkanoates such as polyhydroxybutyrate (PHB). This bioplastic is produced by fermentation and has different properties, depending on the composition – from hard like ABS to flexible like soft PVC. Experts rate the market potential of polyhydroxyalkanoates to be accordingly high. Thanks to VINNEX®, the material’s processing window can be expanded and undesired postcrystallization prevented. In addition, the polymer blend is less brittle and significantly more flexible than the pure bioplastic. The elongation at break of a blend containing 10 percent VINNEX® is around 220 percent – almost three times that of pure PHB – and it exhibits slightly enhanced tensile strength.
Another VINNEX® series advantage is that certain formulations can meet the biodegradability criteria for bioplastics specified in ISO 14855. Under industrial composting conditions, the biodegradability in a mixture of PLA, starch and 30 percent VINNEX® reaches the 90-percent mark within 65 days. Just as with cellulose – as the test’s reference substrate – the mixture of starch, biobased and synthetic polymers is largely degraded after two months in the ground.