Multilayer heat shrinkable film
AssigneeVector Europe NV
InventorsRodney L Wallace, Stamatis Ginossatis
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Abstract
A heat shrinkable multilayer film including a thermoplastic heat sealable inner layer, an abuse layer of a thermo-plastic polymer blend having a higher average melting point than said inner layer, and a thermoplastic, optically clear outer layer adjacent said abuse layer, wherein said outer layer has a lower Vicat softening point than said abuse layer. A film in accordance with the invention has high hot water seal strength, high burn-through resistance and superior optical properties without the need for irradiation.
Claims42
A heat shrinkable multilayer film including:
- a heat sealable inner layer of a thermoplastic polymer or a thermoplastic polymer blend;
- an abuse layer of a thermoplastic polymer blend having a melting point at least about 20° C. higher than said inner layer, said abuse layer blend being selected to have substantially balanced shrinkage relative to said inner layer, and
- a thermoplastic, optically clear outer layer adjacent said abuse layer, wherein said outer layer has a lower Vicat softening point as determined by ASTM D-1525 than said abuse layer.
A film according to 28, wherein said one or more thermoplastic layers is an oxygen barrier layer.
A film according to claim 30, wherein said barrier layer includes polyvinylidene chloride, a polyamide barrier material or hydrolyzed ethylene vinyl acetate copolymer.
A film according to any one of claims 1 to 35, wherein said film is a tubular multilayer film formed by coextrusion or coating lamination.
A film according to any one of claims 1 to 36, wherein said film shrinks at least 40% in at least one of machine and transverse directions by measuring unrestrained shrink of the film at 90° C. for about five seconds, or equivalent shrinkage thereof.
A heat shrinkable multilayer film including:
- a heat sealable inner layer of a thermoplastic polymer blend having an average melting point between 94° C. to 96° C.;
- an abuse layer of a thermoplastic polymer blend having an average melting point between 120° C. to 150° C., said abuse layer blend being selected to have substantially balanced shrinkage relative to said inner layer, and
- a thermoplastic, optically clear outer layer adjacent said abuse layer, wherein said outer layer has a lower Vicat softening point as determined by ASTM D-1525 than said abuse layer.
A in a heat shrinkable multilayer film including:
- a heat sealable inner layer of a polymer blend of very lower density polyethylene, ethylene vinyl acetate copolymer, and ethylene α-olefin plastomer copolymer;
- an abuse layer of a polymer blend of polypropylene, polybutylene and ethylene vinyl acetate copolymer or ethylene α-olefin plastomer copolymer, said abuse layer blend being selected to have substantially balanced shrinkage relative to said inner layer;
- an optically clear outer layer adjacent said abuse layer of a polymer blend of ethylene vinyl acetate copolymer, very lower density polyethylene and polypropylene.
41 A film according to any one of claims 37 to 40, wherein the Vicat softening point of the outer layer is less than about 111° C.
42 A film according to any one of claims 42, wherein said Vicat softening point is in the range of 70° C. to 8° C.
Dependencies are inferred from the claim text.