The invention aims at providing a polylactic acid composition having specific thermal characteristics and gas barrier properties and at obtaining a polylactic acid composition comprising PLLA and PDLA which composition can form moldings (such as stretched film) excellent in surface smoothness, transparency, heat resistance, and toughness. Specifically, a polylactic acid composition characterized by exhibiting a peak of 30 mJ/mg or above in DSC as determined by cooling at a rate of 10 °C/min after the lapse of 10 min at 250 °C, preferably a polylactic acid composition characterized by exhibiting a peak (1)/peak (2) ratio of 0.5 or below wherein the peak (1) and peak (2) correspond to a peak of Tm of 150 to 180 °C and a peak of Tm of 200 to 240°C respectively in DSC as observed in the second heating (namely, re-heating from 0 °C at a rate of 10 °C/min which follows the cooling at a rate of 10 °C /min conducted after the lapse of 10 min at 250 °C).
本发明旨在提供一种具有特定热特性和气体阻隔特性的聚
乳酸组合物,并获得一种由聚
乳酸(PL
LA)和聚
对苯二甲酸(PD
LA)组成的聚
乳酸组合物,该组合物可形成表面光滑度、透明度、耐热性和韧性极佳的成型品(如拉伸薄膜)。具体地说,一种聚
乳酸组合物,其特征是在 250 °C 下经过 10 分钟后,以 10 °C/min 的速度冷却所测定的
DSC 中的峰值为 30 mJ/mg 或以上,最好是一种聚
乳酸组合物,其特征是峰值(1)/峰值(2)比为 0.5或以下,其中峰(1)和峰(2)分别对应于在第二次加热(即在250℃下10分钟后以10℃/分钟的速率冷却后,以10℃/分钟的速率从0℃重新加热)中观察到的
DSC中的150至180℃的Tm峰和200至240℃的Tm峰。