| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject low oligomeric polyester film that is excellent in long-term heat resistance and in productivity and can be used for motor insulation for refrigerator or a variety of electric insulation uses by using a non-liquid crystal polymer and a polyester copolymer. SOLUTION: This objective polyester film comprises (A) <=0.5 wt.%, preferably <=0.35 wt.% of a non-liquid crystal polyester (this polyester is mainly constituted with an aromatic dicarboxylic acid, an alicyclic carboxylic acid or an aliphatic dicarboxylic acid and diols and (B) 0.01-5 wt.%, preferably 0.1-1 wt.% of a polyester copolymer bearing mesogen groups in the main chain (a polyester copolymer comprising aromatic oxycarbonyl units and aromatic dioxy units) and has <=140 deg.C, preferably <=130 deg.C of the heat-up crystallization temperature, 0.6-2.5 dl/g (preferably 0.8-1.5 dl/g of intrinsic viscosity. |
