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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsYasuo Kawashima, Yasuhiro Fujii, Takeshi Kanamori
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As pellets suddenly soften by crystallization heat at a temperature equal to or higher than the glass transition temperature due to the characteristics of polylactic acid and a blocking phenomenon occurs, there is a need for inhibiting the blocking phenomenon. It is thus an object of the present invention to improve productivity of a polylactic acid resin and a polylactic acid-based resin composition comprising polylactic acid as a main component by inhibiting the blocking phenomenon. Aiming at solving above problems, in the present invention, a resin composition comprising polylactic acid or a blend of polylactic acid and another resin obtained by manufacturing the polylactic acid by polymerization or blending the polylactic acid and the another resin after manufacturing the polylactic acid is subjected to a heat treatment at a temperature of the glass transition temperature of polylactic acid ±10° C. for 15 minutes or more before a drying and crystallization treatment.
1-5. (canceled)
A polylactic acid-based resin composition having a degree of crystallinity of 30% or less, comprising polylactic acid and having a specific heat capacity variation of 0.4 J/(g·° C.) or less in a temperature range of from 50° C. to 80° C., the specific heat capacity variation being measured by temperature-modulated differential scanning calorimetry in which a temperature is raised from 50° C. to 80° C. by multi-stages with temperature modulation for 10 minutes at each temperature from 50° C. to 80° C. under the conditions of a temperature modulation amplitude of ±0.5° C. and a temperature modulation period of 60 seconds.
Dependencies are inferred from the claim text.