Method for producing laminated porous sheet comprising polytetrafluoroethylene and carbon particles

Abstract

The method for producing the porous sheet of the present invention includes the steps of (I) preparing a plurality of sheet materials that contain polytetrafluoroethylene and carbon particles and (II) stacking the plurality of sheet materials over one another and rolling the stacked sheet materials. In the method for producing the porous sheet of the present invention, step (I) and step (II) may be repeated alternately. Further, as the sheet materials to be used in the production method of the present invention, a base sheet obtained by forming a mixture containing polytetrafluoroethylene and carbon particles into sheet form also can be used, or a laminated sheet obtained by stacking a plurality of base sheets over one another and rolling them also can be used, for example.

1 - 4 . (canceled) 
     
     
         5 . A porous sheet containing polytetrafluoroethylene and carbon particles, the porous sheet having a thermal conductivity in the thickness direction of at least 0.05 W/mK but not more than 0.1 W/mK and a volume resistivity in the thickness direction of at least 0.5 Ω·cm but not more than 2 Ω·cm. 
     
     
         6 . The porous sheet according to  claim 5 , the porous sheet having a compressive elastic modulus at 5% strain in the thickness direction of at least 0.5 MPa but not more than 2 MPa. 
     
     
         7 . A heat insulating sheet produced using the porous sheet of  claim 5 .