Abstract: The present invention is directed toward a film comprising a vinylidene chloride interpolymer, wherein the vinylidene chloride interpolymer having polymerized herein vinylidene chloride in an amount of from about 75 to about 95 percent by weight of interpolymer and from about 25 to about 5 percent by weight of interpolymer of at least one monomer copolymerized therewith, is prepared by extruding said interpolymer through an extrusion die to form an extrudate; passing the extrudate through a cooling means; blowing a blown tubular bubble by expanding the cooled extrudate sheet around a trapped gaseous medium, said bubble having an effective blow-up ratio before deflation such that the bubble after deflation has a desired final blow-up ratio; and conveying the tubular bubble through a deflator means to collapse the bubble into a two-layer film, wherein the film has a final blow-up ratio of between about 2.5 to about 3.
Type:
Grant
Filed:
January 3, 1989
Date of Patent:
December 17, 1991
Assignee:
The Dow Chemical Company
Inventors:
Edward M. Jorge, Antonio Torres, Monty M. Lund, deceased