| abstract |
A method for the manufacture of a porous or voided film or coating comprising application on to a substrate a water-in-oil emulsion comprising a film-forming resin, such as polyvinyl butyral, styrene/maleic anhydride copolymer, vinyl chloride copolymer, vinyl chloride/vinyl acetate/vinyl alcohol terpolymer, dissolved in a solvent. The film-forming resin is mixed with water, preferably water with a water soluble or miscible polymer, such as a salt of polyacrylic acid, and then drying the water-in-oil emulsion. The method is particularly suitable for the manufacture of heat sensitive stencils for use on stencil and/or digital duplicators. |