| 摘要 |
1,138,121. Microporous polyurethanes. CONTINENTAL GUMMI - WERKE A.G. 30 March, 1967 [11 June, 1966], No. 14486/67. Headings C3C and C3R. [Also in Division B2] Microporous polyurethanes are prepared by reacting a polyol and a polyisocyanate in the presence of a catalyst and (a) in the one-step method, one or more optionally halogensubstituted hydrocarbons having a b.p. of at least 100‹ C., or (b) in the prepolymer method, in the second stage thereof, one or more optionally halogen-substituted hydrocarbons of b.p. above 50‹ C., the reaction mixture being emulsified then moulded at temperatures below the boiling-point of the optionally halogensubstituted hydrocarbons and set, and after setting, the optionally halogen-substituted hydrocarbon expelled. Conventional polyols, polyisocyanates and catalysts are used. The optionally halogen-substituted hydrocarbons may be those of the alkane series having more than 6 carbon atoms especially those of a paraffinic or naphthenic nature which are present as viscous liquids in the reaction mixture. To facilitate emulsification of such compounds they may be mixed with low boiling- point hydrocarbons. In examples, the optionally halogen-substituted hydrocarbons used are petroleum distillation products, and a benzenetype hydrocarbon. The optionally halogensubstituted hydrocarbon may be expelled by heating the polymers to evaporate the hydrocarbon and may be assisted by connecting to a vacuum or the hydrocarbon may be dissolved out with a suitable solvent. Hydrophilic fillers such as starch and bentonite may be added along with the hydrocarbon, as may emulsifying agents such as polysiloxane-polyethers and ester oils. The optionally halogen-substituted hydrocarbon is most suitably dispersed in one of the reaction components. |
