Patent ID: 6565985
Filing Date: 2003-05-20
Classification: B29C,B32B,Y10T

Abstract:
A heat-shrinkable multilayer film, comprising: at least three layers including an outer surface layer (a) formed of a thermoplastic resin, an intermediate layer (b) formed of a polyamide resin, and an inner surface layer (c) formed of a heat-sealable resin; whereinthe thermoplastic resin forming the outer surface layer (a) comprises a polyester resin or a polyolefin resin, the polyamide resin forming the intermediate layer (b) comprises a mixture of 85-60 wt. % of an aliphatic polyamide resin, and 15-40 wt. % of an aromatic copolyamide resin which is a copolymer of aliphatic diamine/isophthalic acid and aliphatic diamine/terephthalic acid, the heat-sealable resin forming the inner surface layer (c) essentially comprises a copolymer of ethylene and an &agr;-olefin, the copolymer having a density below 0.915, the heat-shrinkable multilayer film has been biaxially stretched and then heat-treated to have hot-water shrinkabilities of at least 30% in each of longitudinal/transverse directions and at least 35% in at least one of longitudinal/transverse directions, as measured after dipping the multilayer film in water at 80Â° C. for 10 seconds, and the heat-shrinkable multilayer film has a characteristic of size change of at most 5% in both of longitudinal/transverse directions after standing for 2 weeks in an environment of 23Â° C. and 50%-relative humidity.