| 摘要 |
PROBLEM TO BE SOLVED: To provide a polylactic acid by using fermented lactic acid liquid as a raw material by using a direct and continuous polymerization method with single equipment, in a good workability and inexpensively. SOLUTION: This method for producing the polylactic acid by using the fermented lactic acid liquid as the raw material and repeating polycondensation reactions by a multiple number of times continuously to enable the practical production of the polylactic acid is characterized by flash plate-ejecting the fermented lactic acid liquid into a first polycondensation chamber 5 for performing the polycondensation reaction under a reduced pressure in the first polycondensation chamber 5, while dehydrating, then flash plate-ejecting the above product into a second polycondensation chamber 8 for performing the polycondensation reaction under a reduced pressure in the second polycondensation chamber 8 and then flash plate-ejecting the above product into a third polycondensation chamber 13 under a nitrogen super critical or semi-critical condition for performing the polycondensation reaction under a reduced pressure in the third polycondensation chamber 13. COPYRIGHT: (C)2008,JPO&INPIT
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