Multi-layer barrier film
AssigneeAmerican Can Company
InventorGeorge O. Schroeder
Life of this patent
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Abstract
A delamination resistant multi-layer film comprises a core layer of vinyl alcohol polymers or copolymers such as polyvinyl alcohol or ethylene vinyl alcohol. Adhered to the core layer are one or more layers of a polyolefin blended with a chemically modified polyolefin having functional groups added to the basic polymer such that strong adhesion to the core layer is obtained. The core layer provides an excellent oxygen barrier, while the adjacent layers protect the core layer from degradation by exposure to water vapor. Additional layers of various polymer materials may be provided over the layers of modified polyolefin. The film can be prepared by coextrusion techniques.
Claims36
A delamination resistant multi-layer structure comprising a barrier layer of a substantially pure polymer or copolymer of vinyl alcohol adhered directly to a layer of a modified polyolefin which consists essentially of a polyolefin polymer or copolymer blended with a graft copolymer of polyethylene and an unsaturated fused ring carboxylic acid anhydride.
A delamination resistant coextruded multi-layer structure comprising a barrier layer of substantially pure ethylene vinyl alcohol copolymer located between adjacent layers consisting essentially of a modified polyolefin which consists of a polyolefin polymer or copolymer blended with a graft copolymer of polyethylene and an unsaturated fused ring carboxylic acid anhydride.
A delamination resistant coextruded multi-layer structure comprising
- (a) a substantially pure ethylene vinyl alcohol copolymer core layer;
- (b) a modified polyolefin layer on each side of and adjacent the core layer, the modified polyolefin consisting essentially of a graft copolymer of polyethylene and an unsaturated fused ring carboxylic acid anhydride blended with a polyolefin selected from the group consisting of polyethylene and ethylene vinyl acetate copolymer;
- (c) an outer polymer layer over at least one of the modified polyolefin layers, the outer layers being independently selected from the group which consists of polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, blends of two or more of the foregoing polymers, nylon, and ionomers.
A delamination resistant coextruded multi-layer structure comprising a barrier layer of substantially pure ethylene vinyl alcohol copolymer located between adjacent layers of a modified polyolefin which consists essentially of a blend of ethylene vinyl acetate copolymer and a graft copolymer of high density polyethylene and an unsaturated fused ring carboxylic acid anhydride.
A delamination resistant coextruded multilayer structure comprising a barrier layer of substantially pure ethylene vinyl alcohol copolymer and an adjacent layer of modified polyolefin which consists essentially of a blend of ethylene vinyl acetate copolymer and a graft copolymer of high density polyethylene and an unsaturated fused ring carboxylic acid anhydride.
Dependencies are inferred from the claim text.