PURPOSE: To obtain a copolymer of α-methylstyrene and acrylonitrile having good composition uniformity and impact strength by subjecting α-methylstyrene and acrylonitrile to the emulsion polymerization under such a specific condition that excess unreacted α-methylstyrene is present and then, adding the entire monomers to complete the emulsion polymerization.
CONSTITUTION: A first monomer feed flow containing α-methylstyrene and acrylonitrile at a weight ratio of 77/25-85/15 is filled in a reactor containing 0.05-5.0 wt.% polymer seed latex under the emulsion polymerization condition until, based on the total weight of the monomers and a polymer, the amount of unreacted α-methylstyrene and acrylonitrile comes to 20-45% and, at the same time, the amount of unreacted α-methylstyrene comes to 670-5,000 wt.% based on unreacted acrylonitrile and subsequently, a second feed monomer flow containing acrylonitrile in the absence of α-methylstyrene is filled in the reactor until the amount of unreacted monomers comes to 5-15% based on the total monomer weight, and until the conversion reaches 90 wt.%, the emulsion polymerization is continued to obtain the desired copolymer.
ROBAATO PII DEION
NOOMAN EI RIIFUBAA
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