The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 20, 2003
Filed:
Sep. 26, 2001
Takahisa Ueyama, Ibaraki-ken, JP;
Tadayoshi Itoh, Ibaraki-ken, JP;
Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A polyamide resin-based heat-shrinkable multilayer film is caused to satisfy various properties required of a packaging material, especially a food packaging material, at high levels, and particularly exhibit a highest level of heat-shrinkability. The multilayer film comprises at least three layers including an outer surface layer (a) which comprises a polyester resin or a polyolefin resin; an intermediate layer (b) which 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, and an inner surface layer (c) which essentially comprises a copolymer of ethylene and &agr;-olefin having a density below 0.915. The heat-shrinkable multilayer film has been biaxially stretched and then heat-treated to have hot-water shrinkabilities at 80° C. of at least 30% in each of longitudinal/transverse directions and at least 35% in at least one of longitudinal/transverse directions.