W. R. Grace Co.

Joseph Z Sun

Alan S Weinberg

Henry G Schirmer

Norman D Bornstein

Donald J D'Entremont

A multi-layer film having a crosslinked layer of an olefin vinyl alcohol copolymer is produced by providing a substrate layer and a layer of a copolymer of an olefin and a vinyl ester. The multi-layer structure is crosslinked preferably by irradiation and then hydrolyzed to convert the olefin/vinyl ester copolymer into a copolymer of the olefin and vinyl alcohol. The thus produced structure may be incorporated into a further film combination by extrusion coating additional layers. The multi-layer structure may be oriented to produce a heat shrinkable film for use as a packaging material.

Multi-layer film containing a layer of crosslinked ethylene/vinyl

This invention is a process for making a self-welding packaging film by blending at least two ethylene polymers, one of the polymers having a melt flow substantially greater than any of the other polymers in the blend, and thereafter extruding a film from the blend. The film may be self-supporting or it may be an inner layer in a multi-ply film. Preferred ethylene polymers for the blend are the ethylene-vinyl acetate copolymers wherein one copolymer has a melt flow of less than 5.0 and the other has a melt flow greater than 28.0.

Self-welding packaging film

This invention is a self-welding packaging film made by blending at least two ethylene polymers, one of the polymers having a melt flow substantially greater than any of the other polymers in the blend, and thereafter extruding a film from the blend. The film may be self-supporting or it may be an inner layer in a multi-ply film. Preferred ethylene polymers for the blend are the ethylene-vinyl acetate copolymers wherein one copolymer has a melt flow of less than 5.0 and the other has a melt flow greater than 28.0.

Packaging film comprising a blended self-welding layer

A heat shrinkable multi-layer packaging film having a layer of a hydrolyzed ethylene-vinyl acetate copolymer. Preferably, the film is formed by coextruding the hydrolyzed ethylene-vinyl acetate copolymer layer between two other polymeric layers, at least one of which is cross-linkable, and thereafter irradiating and orienting the multi-layer structure. The resulting film is heat shrinkable and has very low oxygen permeability.

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Spartanburg, SC, United States of America

Joseph Z Sun