| abstract |
A process for continuously producing a linear lactide copolymer having a weight-average molecular weight of from 20,000 to 400,000 using a continuous reaction apparatus composed of three or more stirred flow reactors connected in series, which process comprises the steps of continuously feeding from 50 to 98 parts by weight of a lactide and from 2 to 50 parts by weight of a polymer having a hydroxyl group in a molten state or as dissolved in a solvent to the first reactor of said continuous reaction apparatus, and transferring the reaction mixture from said first reactor to the following reactors successively while maintaining the reaction pressure and the reaction temperature in every reactor in the range of from 1 to 5 atm. and of from 140° to 210° C., respectively, to conduct ring opening copolymerization. According to the process of the present invention, the production problems associated with conventional continuous production methods for lactide copolymers, i.e., high viscosity of the reaction system, thermal decomposition of the polymer produced, and coloration of the polymer produced can be eliminated, and a degradable lactide copolymer endowed with broader range properties than conventional lactide copolymers and therefore useful in wider fields can be obtained continuously and efficiently. |