The present invention relates to the production of lactic acid-based polyurethanes. In the first phase of the production, monomeric lactic acid is polymerized into an oligomer having a molecular weight of about 500 to 10,000. Next, the oligomer thus obtained is copolymerized with an isocyanate which reacts with the free hydroxyl and carboxyl groups of the oligomer to produce a high molecular weight polyurethane. The lactic acid used need not be absolutely pure. Various biodegradable end products can be obtained suitable for use as material for disposable packages, agricultural film or planting pots, or a coating for fertilizer granules.
|IPC||C08L 101/ 16 A I|
|Publication status||Published - 20 Apr 1994|
|MoE publication type||H1 Granted patent|