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. 09, 2000
Filed:
Jul. 29, 1998
Donald W DuBois, Irwin, PA (US);
Bernard A Maloney, Murrysville, PA (US);
Jerry N Kinney, Harrison City, PA (US);
PPG Industries Ohio, Inc., Cleveland, OH (US);
Abstract
A method of forming a liquid-permeable asbestos-free diaphragm on a cathode structure is described. The method comprises forming a liquid-permeable diaphragm base mat comprising fibrous synthetic polymeric material, e.g., polytetrafluoroethylene, on a cathode structure, e.g., a foraminous cathode; drawing a liquid slurry comprising an aqueous medium containing a wetting amount of surfactant and water-insoluble inorganic particulate material through the base mat, thereby to deposit said inorganic particulate material on and within the pre-formed base mat; and drying the resultant diaphragm at temperatures less than the temperature at which decomposition by-products of the surfactant are formed. The liquid slurry is substantially free of alkali metal halide and alkali metal hydroxide; and the inorganic particulate material comprises at least one oxide or silicate of a valve metal, e.g., zirconium oxide, having a median diameter of 0.1 to 5 micrometers, and optionally clay mineral and/or hydrous oxide of zirconium and/or magnesium. In a further embodiment of the present invention, the base mat is dried prior to deposition of the inorganic particulate material.