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US 7,611,652 B2Granted
Monoxially-oriented and annealed films with high cross machine toughness and related process
AssigneeShaw Industries Group, Inc.
InventorsLarry L. English, Jeffrey W. Adams
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Abstract
A monoaxially-oriented polymeric film material formed from an impact copolymer and having increased toughness relative to films that are monoaxially-oriented at conventional temperatures. A process for imparting high cross machine toughness to polymer films comprises forming a film; subjecting the film to monoaxial orientation, drawing the film; tempering the film, and annealing the film.
Claims6
A process for imparting high cross machine toughness to polymer film tape yarns, comprising:
- forming a film from an impact copolymer:
- subjecting said film to monoaxial orientation involving drawing at stages where said film is sequentially directed over a series of rollers as the film is sequentially subjected to a stage of preheating, then a stage of drawing and then a stage of tempering;
- wherein said stage of tempering said film is conducted at temperatures of from between about 20 to about 45 percent lower than the temperature at which said film is subjected to during the stage of drawing;
- annealing said film, wherein said film has an average cross machine toughness value of at least 3,000 lbs/in2 after the annealing step;
- and
- slitting said film subsequent to said annealing.
3 more elements
Dependencies are inferred from the claim text.