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Method for forming microporous fluorocarbon polymer sheet and product

  • US 4,196,070 A
  • Filed: 12/12/1977
  • Issued: 04/01/1980
  • Est. Priority Date: 12/12/1977
  • Status: Expired due to Term
First Claim
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1. In a method for forming a microporous fluorocarbon sheet membrane, the steps of:

  • (a) mixing an aqueous dispersion of fluorocarbon polymer with a pore-forming agent comprising a watersoluble crystallizable metallic organic salt, the crystal of said salt being stable at the sintering point of said fluorocarbon polymer,(b) forming a wet sheet from said aqueous dispersion,(c) concentrating the aqueous dispersion to grow crystals of said dissolved organic salt dispersed through said sheet,(d) drying said crystal-containing sheet,(e) sintering the dry sheet, and(f) leaching the salt crystals from the sheet in an aqueous medium and removing the formed aqueous solution from the sheet.

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