At the "K '95" plastics trade fair, Bayer AG (HQ: D-51368 Leverkusen) presented a plastic which can be composted completely and without residues. This new development is a semi-crystalline, yet translucent to transparent polyester amide. The plastic is resistant to solvents and light, as well as being strong and extremely tough. The melting point of 125 C is remarkably high for a biodegradable plastic. The material is suitable for the manufacture of mulching sheets, rubbish sacks or disposable flower pots, among other things.

Up to now, the property of biodegradability has been equated with the natural origin of the raw materials. Now, however, Bayer has shown that good biological and technical properties can be combined with outstanding processability in a product manufactured from a synthetic raw material. The compostable plastic is water-tight in use and has unlimited storage stability under normal encounters moisture in combination with soil or humus as a carrier of bacteria and fungi – conditions most often found in compost. The biodegradability of the new plastic was investigated in compost according to a German DIN standard. It meets the stringent criteria of this standard, and is completely biodegradable. Furthermore, a specially developed residual polymer analysis method showed that no plastic residues are left in the compost after biodegradation. The plastic is composted just as quickly as lettuce leaves.

The polyester amide can be extruded into films, injection moulded into finished parts, blow-moulded into hollow bodies or spun into fibres. A profile of properties comparable to LDPE was deliberately targeted with respect to resistance to mechanical and thermal loads and processability.

READER SERVICE: Technical information and report "Biologisch abbaubarer thermoplastischer Kunststoff BAK 1095" (Polyester amide): PIE-No. 38367.