Abstract: An object of the present invention is to provide a fiber made of polylactic acid and having excellent strength, heat resistance and heat shrinkage resistance and a manufacturing method thereof. The present invention relates to the fiber is made of a composition which includes (i) poly(L-lactic acid) having a weight average molecular weight of 50,000 to 300,000 (component A), (ii) poly(D-lactic acid) having a weight average molecular weight of 50,000 to 300,000 (component B) and (iii) 0.01 to 5 parts by weight of a phosphate metal salt (component C) based on 100 parts by weight of the total of the components A and B and has a strength of 2.5 to 10 cN/dTex and a manufacturing method thereof.

Abstract: It is an object of the present invention to produce a polylactic acid having a high molecular weight such as a weight average molecular weight (Mw) of more than 100,000 from which only a stereocomplex crystal is grown even by repeating melting and crystallization. The present invention is a process of producing a polylactic acid, including the steps of: (i) obtaining a solid by kneading together poly(L-lactic acid) and poly(D-lactic acid) at a temperature of 160 to 225° C. and crystallizing the kneaded product; and (ii) melt kneading the obtained solid.

Abstract: A polylactic acid composition wherein a ratio (L/D) of an L-lactic acid unit and a D-lactic acid unit is from 30/70 to 70/30; a weight average molecular weight (Mw) is from 100,000 to 300,000; a stereocomplex crystal content (S) is 80% or more; a melting point (Tm) of a stereocomplex crystal is 200° C. or higher; and a degree of randomization (R) is from 0.001 to less than 2.5%, and a fiber thereof.

Abstract: A polylactic acid composition (A) comprising a polylactic acid component (B) comprising at least 90 mol % of an L-lactic acid unit and less than 10% of copolymerizing component units other than L-lactic acid, and a polylactic acid component (C) comprising at least 90 mol % of a D-lactic acid unit and less than 10 mol % of copolymerizing component units other than D-lactic acid, which is a mixed composition with a (B)/(C) weight ratio of between 10/90 and 90/10.

Abstract: An object of the present invention is to provide a composition containing polylactic acid and having improved blow moldability and a blow molded product thereof. The polylactic acid composition meets the following requirements (a) to (g) at the same time: (a) the weight average molecular weight must be 70,000 to 700,000; (b) the total content (metal content) of Sn atom, Ti atom, Al atom and Ca atom must be 3 to 20 ppm; (c) the content of P atom must be 3 to 3,000 ppm; (d) the (total number of gram-atoms of Sn, Ti, Al and Ca)/(number of gram-atoms of P) value must be 0.01 to 5; (e) the content of a compound having a molecular weight of 150 or less must be not more than 0.2 wt %; (f) the COOH terminal group concentration must be not more than 30 equivalents/ton; and (g) the following expressions (1) and (2) must be satisfied: 10 Pa·s<P<100 Pa·s??(1) 10 MPa<S??(2) (P is a melt viscosity at 230° C. and S is a stress at 150° C.).

Abstract: It is an object of the present invention to produce a polylactic acid having a high molecular weight such as a weight average molecular weight (Mw) of more than 100,000 from which only a stereocomplex crystal is grown even by repeating melting and crystallization. The present invention is a process of producing a polylactic acid, including the steps of: (i) obtaining a solid by kneading together poly(L-lactic acid) and poly(D-lactic acid) at a temperature of 160 to 225° C. and crystallizing the kneaded product; and (ii) melt kneading the obtained solid.

Abstract: An object of the present invention is to provide a fiber made of polylactic acid and having excellent strength, heat resistance and heat shrinkage resistance and a manufacturing method thereof. The present invention relates to the fiber is made of a composition which comprises (i) poly(L-lactic acid) having a weight average molecular weight of 50,000 to 300,000 (component A), (ii) poly(D-lactic acid) having a weight average molecular weight of 50,000 to 300,000 (component B) and (iii) 0.01 to 5 parts by weight of a phosphate metal salt (component C) based on 100 parts by weight of the total of the components A and B and has a strength of 2.5 to 10 cN/dTex and a manufacturing method thereof.