Abstract
The present invention relates to a production method of lactic acid-based polyurethanes. In the first phase of the product ion, the monomeric lactic acid is polymerized into an oligomer, the molecular weight thereof being about 500 to 10,000. Next, the oligomer thus obtained is copolymerized with an isocyanate reacting with the free hydroxyl and carboxyl groups thereof into polyurethane with a high molecular weight. To make the oligomer react with diol prior to the copolymerization is unnecessary according to the invention. The lactic acid used need not be absolutely pure, and by modifying the process, various biodegradable end products can be obtained therefrom, which according to the invention are appropriate for the material of disposable packages, agricultural film or planting pots, or as a coating of fertilizer granules.
| Original language | English |
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| Patent number | US5380813 |
| IPC | C08L 101/ 16 A I |
| Priority date | 16/10/1992 |
| Publication status | Published - 10 Jan 1995 |
| MoE publication type | H1 Granted patent |
