Dainippon Ink and Chemicals, Incorporated

Shouji Imamura

Takashi Mihara

Masao Kamikura

Katsuji Takahashi

Toshirou Ariga

Hideyuki Furuta

Toshiro Ariga

A modifier for a polylactic acid comprising a block polymer (C) having a polymer block (A) satisfying relationship (1):7.80&#x2266;&#x3c3;/&#x3c1;&#x3c;8.54

Polylactic acid composition containing modifier

A molding resin formed from a block copolymer comprising polyhydroxycarboxylic acid structural units (I), and polyester structural units (II) derived from a dicarboxylic acid and a diol; wherein the weight ratio (I)/(II) between the polyhydroxycarboxylic acid structural units (I) and the polyester structural units (II) is within a range from 95/5 to 10/90; the resin has a microphase separated structure in which either the polyhydroxycarboxylic acid structural units (I) or the polyester structural units (II) forms domains within a matrix formed by the other structural units; the average domain size of the domains is within a range from 0.08 to 5.0 &#x3bc;m; and the weight average molecular weight of the molding resin is within a range from 10,000 to 400,000.

Molding resin and process for production thereof

A lactic acid polyester (III), having a lactic acid unit (I) and a polyester unit (II) at a weight ratio within the range of 10:90 to 90:10, a weight average molecular weight of 10,000 or more, and a glass transition temperature of 60&deg; C. or below, imparts superior impact resistance to polyhydroxy carboxylic acids while maintaining superior flexibility and transparency and with minimal occurrence of bleedout.

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Sakura, Japan

Shouji Imamura