Patent ID: 11866558

Abstract:
A sheet comprising a plexifilamentary film-fibril network consisting essentially of high density polyethylene in an overlapping multi-directional configuration, the sheet, as-produced from a spin cell, having a normalized Frazier air permeability of between 0.002 and 0.2 m3/m2·minute at 50 gsm, a BET surface area of between 9 and 20 m2/gm, and a normalized hydrohead of between 150 and 250 cm at 50 gsm, wherein the plexifilamentary film-fibril network in an overlapping multi-directional configuration is flash-spun from a spin fluid comprising polymer and spin agent, the spin fluid temperature being 190° C. or greater, the spin agent comprising dichloromethane, the spin fluid having a polymer concentration of 12 to 14 weight percent.