Patent ID: 8246873

Claim:
A method for manufacturing foamed polyolefin tapes comprising: combining a polyolefin resin and a blowing agent to form a mixture; heating and shearing the mixture in an extruder to create a supersaturated solution of gas within the polyolefin resin; maintaining a pressure within the extruder and a die that keeps gas dissolved within the polyolefin resin; feeding the polyolefin resin to the die; positioning a cooling device at a predetermined distance from an outlet of the die; extruding the gas-saturated polyolefin resin solution through the die; exposing the extruded resin to atmospheric pressure for a predetermined amount of time based on the predetermined distance between the cooling device and the outlet of the die to form a foamed resin; cooling the foamed resin with the cooling device to form a foamed polyolefin resin sheet; removing the foamed polyolefin resin sheet from the cooling device; slitting the drawn foamed polyolefin sheet into tapes; orienting the tapes from about 4 to about 8 times their original length; and maintaining line speeds for the tapes at or in excess of 850 feet per minute, wherein the maximum thickness of the foamed oriented polyolefin tape comprises 4 mils.