| 摘要 |
PURPOSE:To obtain a porous sheet-like substance with a lower water absorption capacity by impregnating and/or coating a fibrous base with a water-in-oil type organic solvent/water dispersion of polyurethane, followed by specific procedures. CONSTITUTION:A fibrous base is impregnated and/or coated with a water-in-oil type organic solvent/water dispersion of polyurethane (e.g. a mixture of a reaction product of polytetramethylene glycol, ethylene glycol and diphenylmethane diisocyanate and a product obtained by reacting polypropylene glycol and diphenylmethane diisocyanate, followed by a reaction with ethylene glycol). The organic solvent is distilled off from the dispersion to gel the dispersion to thereby obtain a porous sheet-like substance. In the above process, as a dispersion, use is made of one that contains a water-and oil--repellent [e.g. one obtained from CF3(CF2)nCH2CH2OCOCH=CH2 (where n is 5 to 11; 9 on average), stearyl acrylate and N--methylolacrylamide]. |
