| 摘要 |
PURPOSE:To obtain the subject film having specific density and surface-cleavage index, specified void size and small apparent density and resistant to surface cleavage by adding a specific amount of a polyolefin resin to a polyester and biaxially drawing the film of the resin. CONSTITUTION:The objective film having a film density of 0.6-1.2g/cm<2> (preferably 0.6-0.9g/cm<3>) and a surface cleavage index of <=15 (preferably <=5) is produced by adding 5-30wt.% (preferably 8-15wt.%) of a polyolefin resin (preferably polymethylpentene) to a polyester (preferably polyethylene terephthalate) and biaxially drawing the film of the blended resin. Preferably, the surface roughness Ra of the film is 0.1-1.0mum and the optical density of the film is 0.8-1.6 in terms of a film thickness of 150mum. |
