| 简介 |
PROBLEM TO BE SOLVED : To provide a method for effectively producing polylactic acid-based resin having a high molecular weight, in favorable embodiments, having a high melting point, and excellent in thermal stability and hues.
SOLUTION : This method produces the polylactic acid-based resin through direct polycondensation using lactic acid as a main material, wherein solid phase polymerization is performed after polycondensation with the usage of a film evaporator, preferably in a state free from a solvent, and as a catalyst, at least one kind selected from a tin compound, a titanium compound, a lead compound, a zinc compound, a cobalt compound, an iron compound, a lithium compound, a rare earth compound, and a sulfonic acid compound is used.
COPYRIGHT : (C)2009, JPO&INPIT |
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