Patent ID: 6214440
Filing Date: 2001-04-10
Classification: B29K,B32B,Y10S,Y10T

Abstract:
A biaxially oriented, coextruded polyester film, comprising at least two layers with a base layer B at least 80% by weight of which is composed of a thermoplastic polyester and with another layer applied to the base layer B, wherein at least one outward-facing layer Ai) has, per mm.sup.2 of film surface, a number N of elevations whose respective heights h and diameters d are correlated by the following equations:log N/mm.sup.2 <A.sub.h -B.sub.h *log h/.mu.m, 0.05 .mu.m<h<1.0 .mu.m (1)wherein 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<10.0 .mu.m (2)wherein A.sub.d =3.4; B.sub.d =2.4 andii) has a copolyester coating, wherein said coating is composed of the condensation product of the following monomers or their derivatives capable of forming polyesters:A) from 65 to 95 mol % of isophthalic acid;B) from 0 to 30 mol % of at least one aliphatic dicarboxylic acid of formula HOOC(CH.sub.2).sub.n COOH, where n is from 1 to 11;C) from 5 to 15 mol % of at least one sulfomonomer containing an alkali metal sulfonate group on an aromatic moiety of a dicarboxylic acid;D) a copolymerizable aliphatic or cycloaliphatic glycol having 2 to 11 carbon atoms in the stoichiometric amount necessary to form 100 mol % of condensate;wherein each of the percentages given is based on the total amount of the monomers forming the polyester coating.