| 摘要 |
PURPOSE:A fibrous base is impregnated with a solution of high polymeric elastomer containing a flourine-containing urethane and the solution is coagulated by the wet method, the base is brought into contact with a heater on its surface, then a microporous layer is formed by the wet method on the surface whereby the titled sheet of high smooth surface is obtained. CONSTITUTION:A solution of high polymeric elastomer containing a fluorine- containing urethane (preferably of 12-35wt% fluorine content) which has been obtained by reaction between an urethane prepolymer and a compound containing perfluoroalkyl groups, is used to impregnated a fibrous base. Then, the base is dipped in a nonsolvent medium mainly consisting of water to effect the wet coagulation of the elastomer. Then, the base is brought into contact with the surface of a heater on at least one surface of the base of remove the nonsolvent near the surface layer. The surface treated with the heater is coated with an elastomer solution and coagulated by the wet method to form a microporous layer. The base becomes water-repellent on the whole and the penetration of water into the base is inhibited on the formation of the microporous layer, thus the air bubbles in the base are not pushed out thereby forming dense and uniform foam structure.
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