Musashino Chemical Laboratory, Ltd.

Mutual Corporation

Other

Teijin Limited

Zhen Tang

Yuka Komazawa

Yoshiharu Kimura

Kiyotsuna Toyohara

Ryuji Nonokawa

Tsuyoshi Aoki

Yasuhito Maeda

Kazuki Fukushima

Masayuki Takada

It is an object of the present invention to provide polylactic acid containing a stereocomplex crystal and having excellent moldability, a high molecular weight, high crystallinity and a high melting point and a process for manufacturing the same. It is another object of the present invention to provide a composition comprising the polylactic acid and a molded product of the polylactic acid. The present invention is characterized from polylactic acid having a weight average molecular weight of 80,000 to 500,000 and a melting peak at 195&#xb0; C. or higher which accounts for 80% or more of the total of melting peaks in the temperature elevation step when measured by a differential scanning calorimeter (DSC) and a process for manufacturing the same.

Polylactic acid and manufacturing process thereof

It is an object of the present invention to provide a method for producing a polylactic acid block copolymer having high molecular weight, and in lower cost, wherein only a stereo-complex crystal is capable of growing, even when heat melting process is repeated. The present invention relates to a method for producing a polylactic acid block copolymer characterized in that (i) ring-opening polymerization of D-lactide (D component) is carried out in the presence of poly-L-lactic acid (L component), or (ii) ring-opening polymerization of L-lactide (L component) is carried out in the presence of poly-D-lactic acid (D component), and mass ratio of the D component and the L component is the D component/the L component=60/40 to 91/9, or the L component/the D component=60/40 to 91/9.

Method for producing polylactic acid block copolymer

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Chuo-ku, Japan

Zhen Tang