| 摘要 |
PURPOSE:To suppress the amount of an unreacted monomer remarkably and obtain a heat-resistant copolymer, by adjusting the concentration of the unreacted unsaturated nitrile at a specific value in adding the monomer to a polymerization system of a specific amount of an alpha-alkylstyrene with the unsaturated nitrile. CONSTITUTION:In the emulsion polymerization of 70-80wt% alpha-alkylstyrene, e.g. alpha-methylstyrene, with 30-20wt% unsaturaed nitrile, e.g. acrylonitrile, in the presence of a radical polymerization initiator, the concentration of the unreacted unsaturated nitrile at the completion of the nitrile monomer addition is adjusted to 31% or more based on the total unreacted monomer in the polymerization system, and the monomer is added thereto. For example, the total amount of the alpha- alkylstyrene is previously charged into the polymerization system, and the unsaturated nitrile is continuously added at a rate adjusted according to the measured cocentration of the unreacted nitrile. EFFECT:The amount of the unreacted monomer is suppressed to 1% or less, and the industrial productivity is improved. |
