Breakthrough claimed for bio-based foamable plastic
An American developer has claimed a breakthrough in the development of a bio-based compostable foamable plastic to replace petroleum-based polystyrene foams.
Cereplast claimed that the foamable bio-resin is ideally suited for thermo-forming applications, such as egg cartons, meat trays, and boxes for fruit and mushrooms. It added that the resin, called Compostable 5001, has higher thermal properties than its existing compostable plastics, and can be used on conventional extrusion equipment without process or screw changes.
Bioplastics are already used for disposable items such as shopping bags and plastic cutlery and crockery. They are also used in non-disposable applications where environmentally-sustainable plastics are preferred. Several types exist, most notably those based on starches and on polylactic acids (PLA) - Compostables 5001 uses the latter.
"Compostables 5001 represents an outstanding opportunity for companies across the plastic supply chain, currently using petroleum-based foam plastic resins, to reduce the industry's reliance on oil and contribute to environmental sustainability," declared Frederic Scheer, Cereplast's chairman and CEO.
"A significant breakthrough is the fact we are able to reach a density of about 5 pounds per cubic foot on a traditional screw while keeping acceptable heat deflection, modulus and impact strength," added Philippe Ravera, the company's senior vice-president for sales and marketing. "Compostable 5001 is our first grade of bio-based foamable resins, and we intend to introduce additional grades later this year."
Compostable plastics are being promoted to the food industry, where compostability should be an obvious advantage. There is a caveat, however: many bioplastics will only degrade in the tightly controlled conditions of industrial composting units, not in landfill or in a home composter.
Bioplastics face other challenges too. In particular, they are not compatible with ordinary plastics, which causes problems for the recycling industry. Bioplastic producers hope to overcome this with labelling that ensures their products go for composting, not recycling - although as PLA is also recyclable, advanced (but expensive) sorting technology could also provide an answer.
In addition, the production of bioplastics still requires energy, as does growing the crops that are the industry's feedstock; it also diverts corn out of the foodchain. And some of the corn used as feedstock in the US will be genetically-modified, which raises the hackles of many consumers.