| 摘要 |
PURPOSE:To obtain the title film which is lightweight and improved in light resistance, scratch resistance and hiding power by at least unidirectionally orienting a polyester film containing specified white particles and crystalline PP. CONSTITUTION:2-20wt.% white particle (e.g., BaSO4) of a Mohs hardness <=5, a mean particle diameter of 0.05-5mum, a specific gravity <=6 and a refractive index >=1.5 and 3-40wt.% crystalline PP of an MI of 0.2-120g/10min are added to an aromatic polyester of an intrinsic viscosity >=0.4, and the mixture is melt-kneaded at 250-320 deg.C, extruded into a sheet through a die and cooled to 70 deg.C or below to obtain an amorphous sheet. This sheet is oriented at least unidirectionally in an areal ratio >=4 and heat-treated at 120-250 deg.C to obtain a microcellular polyester film. |
