US 4,082,877 AGranted

Unoriented composite laminar film with an elastomeric layer and sealable layer

AssigneeW. R. Grace & Co.

InventorRobert James Shadle

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Abstract

Disclosed is an extensible composite laminar film useful for packaging which includes a first layer of elastomeric polymeric composition and one or more extensible sealable layers of polymeric composition including an interpolymer of ethylene and alkenoic acid or ionomeric salt thereof. In an embodiment the film has a tensile secant modulus of from about 1,000 to about 30,000 and preferably from about 1,000 to about 14,950 pounds per square inch. The film is prepared advantageously by hot blown coextrusion. When stretch wrapped about a variety of products the film typically exhibits a high degree of elastic recovery. Also disclosed is an elastomeric film-forming composition including an ethylene-vinyl acetate interpolymer and an ethylene-propylene interpolymer desirably having a density of not more tha 0.92. The first layer of the film may effectively be prepared from the composition.

Claims31

Dependent claims

A substantially unoriented composite laminar film having a 10 percent tensile secant modulus of from about 1,000 to about 30,000 pounds per square inch which comprises:

a first layer of elastomeric polymeric composition;
and
a sealable layer of a polymeric composition comprising an interpolymer of ethylene and alkenoic acid;
and wherein,
said elastomeric polymeric composition comprises a material selected from the group consisting of elastomeric interpolymer of ethylene with an alpha-mono-olefin having from 3 to about 8 carbon atoms per molecule, elastomeric interpolymers of styrene with a conjugated diene, elastomeric interpolymers of ethylene and a vinyl ester of carboxylic acid having from 2 to about 5 carbon atoms per molecule, elastomeric polyurethanes, elastomeric polyesters, elastomeric polyethers, and mixtures thereof;
and wherein
said alkenoic acid interpolymer is selected from ionomeric salts of interpolymers of ethylene and an alpha, beta-ethylenically unsaturated carboxylic acid having from 3 to about 10 carbon atoms.

4 more elements

Dependencies are inferred from the claim text.