The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 08, 1979
Filed:
Oct. 15, 1974
Erik G Sundberg, Osbacken, SE;
George A Campbell, Newfoundland, NJ (US);
Edward I Doucette, Hollywood, CA (US);
Aktiebolaget Tudor, , SE;
Abstract
A process for producing a microporous plastic member useful as a battery separator which comprises (a) forming a coherent dough by mixing a vinyl chloride resin with a plasticizing amount of a first solvent and with finely divided particles of a filler which contains volatilizable constituent releasable therefrom by heating and which shrinks substantially and irreversibly upon release of said volatilizable constituent therefrom, an example of which is hydrated silica; (b) forming the solvent-containing dough into a shaped member; (c) extracting the first solvent from the member before any substantial evaporation of solvent occurs by contacting it with a second solvent in a liquid bath at a temperature substantially below the boiling point of any liquid present, the second solvent being one which is capable of dissolving the first solvent without dissolving the resin and the filler, thereby deplasticizing the member by extractively removing the first solvent from the member; and (d) thereafter heating the member at an elevated temperature but below the softening point of the resin until the filler is shrunk within the member by release of its volatilizable content.