| 摘要 |
1,244,429. Microporous sheet material. KANEGAFUCHI BOSEKI K.K. 8 July, 1969 [18 July, 1968], No. 34455/69. Heading B2E. [Also in Division C3] A process for the production of a microporous sheet material comprises coating a solution of a film-forming synthetic polymer consisting of or mainly of polyurethane dissolved in a water-miscible organic solvent on to a base material, treating the coated base material with an aqueous coagulating liquid containing urea and at least one of sodium chloride, aluminium chloride, ammonium chloride, sodium sulphate, aluminium sulphate and ammonium sulphate and washing and drying the coagulated polymer layer. The inorganic salt may be present in amount 100-450 grams per litre and the urea may be present in the coagulating liquid in amount 100-250 grams per litre. The polymer solution may also contain urea. The coagulating liquid may be 30-55‹C. One or more film-forming polymers may be present in the solution of polyurethane such as polyvinyl chloride, polyvinyl alcohol, polyacrylonitrile, polyacrylic ester or polyacrylic acid or copolymers of these. A dyestuff or pigment may be present as well as a reinforcing agent such as talc, calcium carbonate or fine powdered silicic acid. The coating may be applied by knife, roller or spray and the base material may be a woven, knitted or non-woven fabric, sponge or paper or an impervious base such as glass, metal or plastics material from which it may be stripped to form an unsupported film. Reference has been directed by the Comptroller to Specification 1,192,598. |
