GB781512A - Improvements in or relating to paper composed of fibres of polytetrafluoroethylene and other closely related polymers - Google Patents

Abstract

781,512. Paper containing synthetic filaments; laminates. DU PONT DE NEMOURS & CO., E.I. March 25, 1955 [April 27, 1954], No. 8870/55. Classes 96 and 140. Paper is made by felting, e.g. on a papermaking machine, an aqueous pulp having suspended filaments of polymers or telomers or interpolymers of polytetrafluoroethylene (PTFE) and chlorotrifluoroethylene, and optionally, filaments of rock wool, asbestos, or flake mica, a wetting agent, e.g. an alkyl aryl polyethylene glycol, and an anti-foaming agent. The PTFE filaments may be prepared by shredding extruded rod as by rubbing, and may be reduced in a " micropulverizer " hammer mill. The paper thickness may be 0.02 to 0.10 ins. or more or felts about 2 to 2¢ in. thick may be made. It may have air permeability of 5 to 75 cu. ft. at a pressure differential of 0.05 in. of water. It may be sintered at 350‹ to 370‹ C. to improve its strength, or bonded by sintering to an impervious PTFE base, the resulting laminate being suitable for adhering to cloth, metal, or glass by an adhesive applied to its paper surface. Specification 642,269, [Group IV (a)], is referred to.