The Dow Chemical Company

James E Holton

Susan E Dollinger

Robert A Luecke

Disclosed is a process for preparing a biaxially oriented substantially non-shrinkable film comprising coextruding a multilayered film comprising a first and second outer layers of resinous thermoplastic material and a barrier layer of a resinous copolymer of vinylidene chloride and an alkyl acrylate, and biaxially draw-tentering the film at a temperature within about 10.degree. C. of the melting point of the copolymer and less than the melting point of the thermoplastic materials of the outer layers.

Process of biaxially orienting coextruded barrier films of

Disclosed are biaxially oriented, coextruded multilayer barrier films wherein a substantial degree of oxygen impermeability is retained after orientation. The barrier layer of the films comprise a copolymer of vinylidene chloride and an alkyl acrylate, wherein the copolymer has a melting point about equal to or less than the melting point of the thermoplastic material comprising the outer layers of the film and has an oxygen permeability of less than 0.25 cc-mil/100 sq. in.-atm-day based upon the thickness of the barrier layer. Further disclosed are biaxially oriented nonshrinkable multilayer barrier films having barrier layers of a copolymer of vinylidene chloride and from more than 6 to about 10 weight percent methyl acrylate. Further disclosed is a process for making the biaxially oriented, coextruded barrier films.

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Newark, OH, United States of America

James E Holton