| abstract |
(57) [Summary] The present invention provides a novel polyester raw material, and an overall thickness of ≤ 4 µm, a roughness R a <30 nm on at least one film surface, and at least one film surface. Gas flow resistance of t ≦ a · d b [sec] (in the formula, a = 0 to 10,000 [sec / μm], b = 3. 0 to 0, d (overall film thickness) ≦ 4 μm. ) Disclosed is the manufacture and use of stretched, monolayer or multilayer films. |