| 摘要 |
PURPOSE:To produce a thermoplastic resin of excellent heat resistance while keeping the reaction system in a state of a stable emulsion, by polymerizing a mixture of a maleimide monomer and a vinyl monomer in an aq. emulsion in the presence of a small amount of a silicon compound. CONSTITUTION:100pts.wt. monomer mixture comprising 1-50wt% maleimide monomer (e.g., maleimide or N-phenylmaleimide) and 99-50wt% other vinyl monomers copolymerizable therewith [e.g., styrene or methyl (meth)acrylate] are polymerized in an aq. emulsion emulsion at 30-120 deg.C in the presence of 0.01-10wt% silicon compound (e.g., silica powder). Conventionally, when the monomer mixture is polymerized in an aq. emulsion, the pH shifts to an acidic side with the progress of polymerization, the state of emulsion becomes unstable, and polymer deposition in a polymerization kettle and on impellers is marked, so that such a conventional process is not suitable for industrial production. By the addition of the silicon compound to the monomer mixture, it is possible to produce the copolymer while the reaction system is being kept in a state of a stable emulsion.
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