Fluoropolymer articles having a high surface roughness and high coarseness

Abstract

Fluoropolymer articles having a high surface roughness and high coarseness are provided. In one embodiment, a fiber is provided that has a surface roughness expressed as a peak-to-valley distance (Rt) greater than 10 micrometers and an average surface roughness (Ra) greater than 1.5 micrometers. In another embodiment, a membrane having a coarseness index ρ/EBP of at least 0.3 g/cm3/psi and an air permeability of 15 ft3/ft2/min or higher is provided. The fluoropolymer articles are produced by a process that includes forming a paste-formed fluoropolymer product at a temperature lower than 50° C., densifying the paste-formed product, and then stretching the dens Pied paste-formed fluoropolymer product in at least one direction. In exemplary embodiments, the fluoropolymer may be polytetrafluoroethylene (PTFE), a modified PTFE, a TFE copolymer, a fluorothermoplastic, a fluoroelastomer, or combinations thereof.

Dependencies are inferred from the claim text.