| 摘要 |
1,054,165. Continuous polyurethane processes. MONSANTO CO. May 13, 1965 [May 13, 1964], No. 20321/65. Heading C3R. Fibre-forming polyurethane elastomers are prepared by continuously introducing a polymeric glycol reactant at a predetermined, controlled rate into a reaction zone, continuously introducing a molar excess of an organic diisocyanate reactant at a predetermined, controlled rate into said reaction zone, continuously introducing into said reaction zone an organic solvent which is a solvent for and non-reactive with the glycol, the diisocyanate and the isocyanate terminated prepolymer produced by their reaction, maintaining the reaction zone substantially free of substance other than the reactants, the solvent and the prepolymer, continuously withdrawing formed prepolymer from the reaction zone and continuously passing said prepolymer into a polymerization zone, continuously introducing a chain extending agent into said polymerization zone at a predetermined, controlled rate, intimately mixing the contents of said polymerization zone and continuously withdrawing fibre-forming polyurethane elastomer from said polymerization zone. The solvent may be dimethylacetamide or dimethylformamide and the chain extender may be a diamine. The temperature of the reaction zone may be maintained at 25-40‹ C. |
