Polymer film having linear tear properties
AssigneeTower Products, Inc.
InventorsNorman J. Otten, Eldrige H. Presnell
Life of this patent
Estimating the term…
Abstract
Certain blends or mixtures of polyethylene and ionomer resins are blow extruded to make a film having excellent linear tear properties in the direction of extrusion, which property is not found in films of either of the resins alone.
Claims15
A method of imparting linear tear properties in the direction of extrusion to a polymer film comprising the steps of preparing a blend of resins consisting essentially of from about 12% to about 95% ionomer resin and from about 5% to about 88% low density polyethylene resin, and extruding said blend of resins at a stretch ratio of approximately 1.5 to 1 into a film[,] whereby said film exhibits linear tear properties in a direction parallel to the direction of extrusion and an Elmendorf tear strength of from 30 to 125 g.
An extruded polymer film consisting essentially of from about 12% to about 95% of ionomer and the remainder as polyethylene having a density of from about 0.910 to about 0.960, said film being extruded at a stretch ratio of approximately 1.5 to 1 and being capable of being torn in substantially a straight line in the direction of extrusion at a deviation of less than 20.degree. from said straight line, said film having an Elmendorf tear strength of from 30 to 125 g. [
The film of claim [7] 6 wherein the Elmendorf tear strength of said film is from about 30 to about 125 g.
A pouch composed of an extruded polymer film, said pouch having a top edge, bottom edge and side edges, said top and bottom edges being substantially parallel with the direction of extrusion of said film, the film of said pouch consisting essentially of from about 12% to about 95% ionomer with the remainder as polyethylene having a density of 0.910 to about 0.960 and containing from about zero to 7.5% vinyl acetate, the film of said pouch being extruded at a stretch ratio of approximately 1.5 to 1 and having an Elmendorf tear strength of from 30 to 125 g, said pouch being capable of being torn from side to side in substantially a straight line parallel with the direction of extrusion.
A pouch comprising a blow extruded polymer tube section having open ends, said tube being heat sealed adjacent each open end to form an enclosure, said tube consisting essentially of from about 12% to about 95% ionomer with the remainder as polyethylene and zero to about 71/2% vinyl acetate, the heat sealed edges of said tube being perpendicular to the direction of extrusion, said tube being extruded at a stretch ratio of approximately 1.5 to 1 and having an Elmendorf tear strength of from 30 to 125 g, said pouch being capable of being torn in substantially a straight line between the sealed edges thereof.
Dependencies are inferred from the claim text.