Patent ID: 6280833
Filing Date: 2001-08-28
Classification: B29C,B29D,B29K,B32B,Y10S,Y10T

Abstract:
A biaxially oriented, coextruded polypropylene film comprising:(A) a base layer B, at least 80% by weight of which is composed of thermoplastic polypropylene; and(B) one or more additional layers,wherein at least one outward-facing layer A has a number of elevations/protrusions N per mm.sup.2 of film surface area which is related to their respective heights h and diameters d by the following equationslog N/mm.sup.2 <A.sub.h -B.sub.h *log h/.mu.m, 0.05 .mu.m<h<1.0 .mu.m (1)A.sub.h =1.4; B.sub.h =2.5log N/mm.sup.2 <A.sub.d -B.sub.d *log d/.mu.m, 0.2 .mu.m<d<10 .mu.m (2)A.sub.d =3.4; B.sub.d =2.4