| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition having excellent melt-processability and heat-stability and little migrationality and volatility of a plasticizer by blending a polyester which has a specific number average molecular weight and consists of a specific repeating structural unit, and a biodegradable acetyl cellulose. SOLUTION: This resin composition contains 15-45 wt.% of a polyester which has a number average molecular weight of 500-5,000 and consists of a repeating structural unit of the formula as a plasticizer, 55-85 wt.% of a biodegradable acetyl cellulose having a degree of acetylation of 30-56% and an average degree of polymerization of 70-250, and optionally additives such as a stabilizer for heat degradation prevention and heat coloring prevention, a filler, a lubricant, an antistatic agent, a biodegradation promoter or the like. A polyester having a repeating structural unit of the formula is obtained by carrying out ring- opening mutual copolymerization of a mono-epoxy compound such as glycidyl methylate or the like and a dibasic acid anhydrite such as succinic acid anhydrite or the like using a monovalent or bivalent carboxylic acid such as acetic acid, succinic acid or the like as the polymerization starting point. In the formula, Y and Z are each a 1-20C organic group; and q and r are each 1 or more.
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