| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a stretched film composed of a polylactic aid-based composition, excellent in heat resistance, surface smoothness, transparency, gas barrier property and toughness. <P>SOLUTION: The film is formed from a polylactic acid-based composition obtained by blending, at 230 to 260°C, 70 to 30 pts.wt. of a poly-L-lactic acid and 30 to 70 pts.wt. of a poly-D-lactic acid (the total of the both is 100 pts.wt.) wherein the weight-average molecular weights of the both are 150,000 to 350,000 and their optical purity is 99 to 100%, wherein the weight-average molecular weights of both the lactic acids constituting the composition are in the range of 0.3 to 0.6 time a numerical value of a weight-average molecular weight being a weighed average of the original weight-average molecular weights; and the composition exhibits a peak ratio (peak 1/peak 2) of a peak 1 at Tm=150 to 180°C and a peak 2 at Tm=200 to 240°C of ≤0.2 in a first-time temperature-rise measurement of DSC; and the melting point is ≥220°C. <P>COPYRIGHT: (C)2013,JPO&INPIT |
