| 摘要 |
PURPOSE:To obtain a method for producing a porous film or sheet which does not allow a liquid, such as water, to permeate, has uniform and excellent air and moisture permeabilities and is excellent in chemical resistance, dust-freeness and electrical characteristics by mixing at least two dispersions of synthetic resins or high-molecular materials having poor compatibility with each other, applying the mixture on a support and melting it to form a film. CONSTITUTION:A dispersion of a thermoplastic resin (A) is mixed with a dispersion containing a high-molecular material (B) having poor compatibility with the resin A and different in melting point and the mixture is applied on a support, melted and formed into film, thus giving a film or sheet. This film or sheet is stretched at least in one direction at a temperature lower than the melting points of the resin A and the material B. |
