Patent ID: 6159587
Filing Date: 2000-12-12
Classification: B32B,Y10T

Abstract:
Stretchable multilayer film characterized by comprising:at least an outer layer (A) that comprises a copolymer of ethylene with one or more .alpha.-olefins CH.sub.2 .dbd.CHR.sup.I, where R.sup.I is an alkyl radical having from 2 to 10 carbon atoms, said copolymer having a density from 0.915 to 0.945 g/cm.sup.3 and a melt index from 0.01 to 100 g/10' and containing up to 20 mol % of .alpha.-olefins CH.sub.2 .dbd.CHR.sup.I ;at least one intermediate layer (B) that comprises:(i) from 80 to 100 parts by weight of a copolymer of ethylene with one or more .alpha.-olefins CH.sub.2 .dbd.CHR, where R is an alkyl radical having from 1 to 10 carbon atoms, this copolymer having a density from 0.88 to 0.945 g/cm.sup.3 and a melt index from 0.1 to 10 g/10' and containing up to 20 mol % of .alpha.-olefins CH.sub.2 .dbd.CHR.sup.I ;(ii) from 5 to 30 parts by weight of copolymer of propylene with ethylene and/or one or more .alpha.-olefins CH.sub.2 .dbd.CHR.sup.I, where R.sup.I is an hydrocarbon radical having from 2 to 10 carbon atoms, said propylene copolymer containing from 60 to 98% by weight of propylene units and having an insolubility in xylene higher than 70%; and(iii) a heterophasic polymer composition comprising(a) 20-100 parts by weight of a fraction which is insoluble in xylene at room temperature, comprising a propylene homopolymer or a copolymer of propylene with ethylene and/or another .alpha.-olefin CH.sub.2 .dbd.CHR.sup.I, where R.sup.I is an alkyl radical having 2-10 carbon atoms, this fraction containing more than 85% by weight of units derived from propylene; and(b) 30-80 parts by weight of a fraction which is soluble in xylene at room temperature, comprising an amorphous copolymer of ethylene with propylene and/or another .alpha.-olefins CH.sub.2 .dbd.CHR.sup.I, R.sup.I has the meaning said above, this fraction optionally containing minor amounts of a diene and containing more than 15% by weight of units derived from ethylene; and at least another outer layer (C) that comprises a copolymer of ethylene with one or more .alpha.-olefin CH.sub.2 .dbd.CHR.sup.I, where R.sup.I is an alkyl radical having 2-10 carbon atoms, having a density between 0.87 and 0.914 g/cm.sup.3.