| abstract |
An object of the present invention is to provide a method for producing polylactic acid having a high melting point. The present invention relates to a polymer L1 and a polymer L2 mainly composed of L-lactic acid units and having a melting point of 140 to 180 ° C., The polymer D1 and the polymer D2 mainly composed of D-lactic acid units and having a melting point of 140 to 180 ° C. are mixed in a weight ratio (L1 + L2) / (D1 + D2) in the range of 10/90 to 90/10, and at 240 to 300 ° C. A method for producing polylactic acid by heat treatment, comprising the following conditions: M L1 / M L2 = 1.5-3 M D1 / M D2 = 1.5-3 (However, M L1 , M L2 , M D1 and M D2 represent the weight average molecular weights of the polymers L1, L2, D1 and D2, respectively.) Is a process for producing polylactic acid characterized by satisfying [Selection] Figure 1 |