| 摘要 |
1,146,717. Continuously polymerizing vinyl chloride. SOC. EDISON S.p.A. 6 June, 1966 [14 June, 1965], No. 25182/66. Heading C3P. In the continuous polymerization of vinyl chloride alone or with a minor proportion of another monomer at low temperatures, i.e. not greater than the boiling point of the monomer under normal atmospheric pressure, in the presence of a catalyst comprising an organoboron compound and a fluidizing substance capable of keeping the reaction mass highly fluid even at high degrees of conversion, the separation of the polymer and recovery of unpolymerized monomer by contacting a continuous stream of the reaction mixture with a stream of washing water at a temperature of from 10‹ to 30‹ C. containing a small quantity of a substance capable of raising the pH of the water to at least 8, rapidly evaporating the unreacted monomer and fluidizing substance and simultaneously separating the polymer by centrifuging, and eliminating the last traces of catalyst from the evaporated monomer and fluidizing substance before recycling the monomer. Specifications 1,086,497 and 1,128,172 describe fluidizing substances. Substances which raise the pH may be an alkali or alkaline earth hydroxide or salt. The last traces of catalyst are preferably removed from the evaporated monomer and fluidizing substance by washing the mixture with a highly basic organic substance such as amine. The exemplified catalyst is triethyl boron, ethyl ether and cumene hydroperoxide, and the fluidizing substance ethyl chloride. The polymers dissolved in cyclohexanone may be spun into fibres. |
