Patent ID: 9028732
Filing Date: 2015-05-12
Classification: B29C

Abstract:
1. A method for making single-sided, anti-slip films each having an interior layer, a core layer of flexible polyolefin, and an exterior slip-resistant layer based on a polyolefin elastomer, the method comprising steps of: using a film-blowing machine to coextrude from a circular die a multilayer film tube of at least three coextruded layers, wherein the coextruded film tube includes an inner layer corresponding to said interior layer, a middle layer corresponding to said core layer, and an outer layer corresponding to said exterior layer, wherein said outer layer comprises a blowing agent causing gas bubbles to form in the outer layer during said coextrusion, and wherein said tube has a first and second side each including said three layers; drawing the coextruded multilayer film tube away from the circular die at a predetermined speed; at a predetermined distance from the circular die, collapsing the coextruded multilayer film tube during said drawing by passing the film tube between at least two collapsing nip rollers positioned in close proximity to one another so that a first roller of said at least two nip rollers contacts said first side of the coextruded multilayer film tube and a second roller of said at least two nip rollers contacts said second side of the coextruded multilayer film tube, wherein first and second inner layer sides of the first and second film tube sides abut one another as a result of said collapsing without fusing or sticking together; treating the collapsed film tube so as to collapse said plurality of gas bubbles and form a rough, slip-resistant, open-celled exterior surface on first and second outer layer sides of said first and second film tube sides; and cutting the treated film tube proximate first and second edges thereof so as to form two generally identical film layers as said single-sided, anti-slip films each comprising said interior, core, and exterior layers.