| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for restraining the deterioration of the optical density of a lactic acid polymer when the lactic acid polymer is hydrolyzed. <P>SOLUTION: A method for recovering a lactic acid oligomer and/or its derivative comprises: a step (1) of putting the lactic acid polymer having 50,000-2,000,000 weight-average molecular weight and/or its derivative in a reactor and introducing steam into the reactor by decompressing the reactor and/or replacing a gas phase of the reactor with steam; a step (2) of hydrolyzing the lactic acid polymer and/or its derivative in a heated steam atmosphere; a step (3) of discharging the steam by decompressing the reactor and introducing dry air and/or an inert gas; and a step (4) of recovering the lactic acid oligomer having 1,000-50,000 weight-average molecular weight and/or its derivative which are obtained at the step (3). <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
