Multi-layer film containing a layer of crosslinked ethylene/vinyl alcohol copolymer
AssigneeW. R. Grace & Co.
InventorJoseph Z. Sun
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Abstract
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.
Claims11
A process for producing a multi-layer film, comprising the steps of:
- providing a multi-layer structure having a substrate layer having a flexibility suitable for packaging material and a precursor layer of a copolymer of an olefin and a vinyl ester;
- crosslinking said precursor layer to produce a crosslinked precursor layer with at least one crosslink per weight average molecule;
- hydrolyzing said crosslinked precursor layer to produce a multi-layer film having a substrate layer and a copolymer layer of an olefin and vinyl alcohol.
Dependencies are inferred from the claim text.