Patent ID: 9017817
Filing Date: 2015-04-28
Classification: B29C,B29K,B32B,C08J,Y10T

Abstract:
1. A method for producing a porous sheet comprising steps of: (I) preparing a plurality of sheet materials, wherein each of the sheet materials comprises polytetrafluoroethylene, carbon particles, and a forming aid; and (II) stacking the plurality of the sheet materials over one another and rolling the stacked sheet materials, wherein the each of the sheet materials is a base sheet or a laminated sheet of the base sheets, the forming aid consists of one or more saturated hydrocarbons, an amount of the carbon particles in the sheet materials is from 60 to 90 wt % relative to a total amount of the polytetrafluoroethylene and the carbon particles, the step (I) and the step (II) are repeated alternately, and the porous sheet has a porosity from 70 to 80 vol %, and wherein the base sheet is prepared by a method comprising steps of: mixing the polytetrafluoroethylene, the carbon particles, and the forming aid under a condition in which forming a fibrous polytetrafluoroethylene is suppressed so as to form a mixture; and then forming the base sheet of the mixture in a sheet form.