| 摘要 |
A method for producing a poly(lactic acid) resin, the method comprising the steps of:
carrying out direct polycondensation using lactic acid as a main raw material to prepare a crystallized prepolymer having a weight average molecular weight of 5,000 to 25,000, an enthalpy of fusion ”Hm of 50 to 65 [J/g] and an acid value A [mol/ton] satisfying the Inequality (1) below: 450 / Mw / 10 , 000 - 0.14 < A < 950 / Mw / 10 , 000 - 0.14
(wherein Mw represents the weight average molecular weight of the crystallized prepolymer); and
subjecting the crystallized prepolymer to solid-phase polymerization. A method for producing an aliphatic polyester resin having a high molecular weight and, in a preferred embodiment, having a high melting point as well as excellent thermal stability and hue can be provided. |
