Slip-resistant polyolefin film and process for preparation thereof

A method of producing a slip-resistant polyolefin thin film comprising the steps of:

• forming a mixture of comminuted rubber material and a thermoplastic low molecular weight polyolefin polymer;
• feeding the mixture into an extrusion means to melt said polymer and thereafter pumping said mixture through an extrusion die to plasticize said mixture;
• providing a pair of parallel, counter-rotating first and second rolls in pre-set operatively close spaced relation, said first roll providing a generally smooth first outer circumferential surface and said second roll providing a generally smooth second outer circumferential surface, the circumferential surfaces together defining a nip between the rolls;
• extruding said plasticized mixture from said die onto said first and second surfaces so as to produce an inventory of said plasticized mixture atop said nip;
• cooling said inventory so as to cause the temperature of the inventory contacting said first outer circumferential surface to be between 75 to 150 degrees Fahrenheit cooler than the inventory contacting the second outer circumferential surface;
• drawing said inventory into said nip so as to form a thin film of ordered thickness having opposite first and second surfaces respectively contacting the first and second outer circumferential surfaces of said first and second sizing rolls;
• drawing the thin film thus formed from said nip through one or more cooling stages to further cool and stabilize said thin film;
• collecting the thin film thus stabilized on one or more winder rolls adapted for such collection;
• wherein the first surface of said thin film thus produced is relatively more slip-resistant than the second surface of said thin film.