| 摘要 |
PURPOSE:To improve mobility, sticking resistance and printability by setting the apparent density and thickness of a film containing many fine independent bubbles to a specific range. CONSTITUTION:The apparent density of a film containing many fine independent bubbles is 0.6-1.3g/cm<3>, and the thickness of the film is set to 1-25mum. Its melt flow index is 0.2-120 and desirably 0.5-50. 3-40wt.% of crystalline polypropylene in which at least 90mol% or more and desirably 95mol% or more is propylene unit is mixed in a polyester, which is extruded as a material by an extruder to be melted and kneaded at 250-330 deg.C, extruded in a sheet state from a die, cooled to be solidified at approx. 30-80 deg.C to obtain a substantially amorphous sheet. Then, it is elongated longitudinally and/or laterally 4 times or more of area magnification and desirably 9 times of more, and further heat treated at 120-250 deg.C to be easily manufactured. |
