Title:
PROCESS FOR PRODUCING POLYHYDROXYCARBOXYLIC ACID
Document Type and Number:
WIPO Patent Application WO/2000/078840
Kind Code:
A1
Abstract:
A process for producing a polyhydroxycarboxylic acid having a weight-average molecular weight of 50,000 to 1,000,000 which comprises: a crystallization step comprising (A) a step in which pellets of a polyhydroxycarboxylic acid having a weight-average molecular weight of 2,000 to 100,000 obtained by liquid-phase polycondensation are heated with stirring at a temperature not lower than the glass transition point but not higher than the melting point until the area of the endothermic peak of the polyhydroxycarboxylic acid which corresponds to the heat of crystallization thereof and is observed upon temperature-rising analysis with a differential scanning calorimeter becomes 38 J/g or larger and (B) a step in which the polyhydroxycarboxylic acid is heated to a temperature at which solid-phase polycondensation occurs; and a solid-phase polycondensation step in which the crystallized polyhydroxycarboxylic acid is reacted at a temperature not higher than the lowest temperature in the endothermic peak observed in temperature-rising analysis with a differential scanning calorimeter.
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Inventors:
HIRAOKA SHOUJI (JP)
TSUBOI HITOSHI (JP)
SAKAI MASAYUKI (JP)
TSUBOI HITOSHI (JP)
SAKAI MASAYUKI (JP)
Application Number:
PCT/JP2000/004069
Publication Date:
December 28, 2000
Filing Date:
June 22, 2000
Export Citation:
Assignee:
MITSUI CHEMICALS INC (JP)
HIRAOKA SHOUJI (JP)
TSUBOI HITOSHI (JP)
SAKAI MASAYUKI (JP)
HIRAOKA SHOUJI (JP)
TSUBOI HITOSHI (JP)
SAKAI MASAYUKI (JP)
International Classes:
B29B9/12; B29B9/16; C08G63/78; C08G63/80; C08G63/06; (IPC1-7): C08G63/78
Foreign References:
| JPH08269175A | 1996-10-15 | |||
| JPH08193124A | 1996-07-30 |
Other References:
See also references of EP 1114840A4
Attorney, Agent or Firm:
Mogami, Shotaro (Akasaka 1-chome Minato-ku, Tokyo, JP)
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