Patent ID: 6117553
Filing Date: 2000-09-12
Classification: B32B,C08J,C08L,Y10T

Abstract:
A self-tack wrapping film comprising a non-oriented multi-layer film of a chlorine-free resin, wherein said multi-layer film comprises outer layers and a core layer in the form of outer layer/core layer/outer layer wherein the outer layer comprises propylene block copolymer obtainable by a process which comprises producing 40 to 85% by weight of a component A which is a propylene-ethylene copolymer having an ethylene content of 1.5 to 6.0% by weight as a first step, and producing 60 to 15% by weight of a component B which is a propylene-ethylene copolymer having an ethylene content of 7 to 17% by weight as a second step, wherein an intrinsic viscosity of the component B ([.eta.]B) is from 2 to 5 dl/g and a ratio of the intrinsic viscosity of the component B to that of the component A ([.eta.]A), [.eta.]B/[.eta.]A, is from 0.5 to 1.8 and the core layer comprises a resin selected from the group consisting of polycarbonate and styrene-based resins, wherein the styrene-based resin is selected from the group consisting of polystyrene, acrylonitrile-styrene copolymer resin, and methacrylic acid-styrene copolymer resin, and wherein said multi-layer film satisfies the following properties (a) to (h),(a) tensile breaking elongation at a longitudinal direction (ELD) being from 10 to 150%,(b) ratio of a tensile breaking elongation at a transverse direction (ETD) to the tensile breaking elongation at a longitudinal direction (ELD), ETD/ELD, being from 0.5 to 3,(c) tensile breaking load at a longitudinal direction (LLD) being from 150 to 800 kg/cm.sup.2,(d) ratio of the tensile breaking load at a longitudinal direction (LLD) to a tensile breaking load at a transverse direction (LDT), LLD/LTD, being from 0.5 to 2,(e) tensile modulus at a longitudinal direction and that a transverse direction being from 200 to 8000 kg/cm.sup.2, respectively,(f) tackiness being from 3 to 20 g/10 cm,(g) heat resistant temperature being 140.degree. C. or higher, and(h) thermal shrinkage percent at a longitudinal direction and that at a transverse direction being 10% or less.