| 摘要 |
PURPOSE:To obtain the titled copolymer excellent in heat resistance at a high polymer conversion, by emulsion-polymerizing an alpha-alkyl-substituted aromatic vinyl monomer with a vinyl cyanide monomer in a polymerization system of a pH kept in a specified range. CONSTITUTION:A mixture comprising 70-90wt% alpha-alkyl-substituted aromatic vinyl monomer (A) (e.g., alpha-methylstyrene), 10-40wt% vinyl cyanide monomer (B) (e.g., acrylonitrile) and, optionally, 40wt% or below other vinyl monomers [e.g., (meth)acrylic acid] is polymerized in the presence of, optionally, an anionic emulsifier, a polymerization initiator, a polymerization initiator aid and a polymerization degree modifier to a polymer conversion >=30% by keeping the pH in the polymerization system in the range of 9.5-11.5 by the addition of a basic compound (e.g., NaOH) or an acid (e.g., sulfuric acid).
|
