| 摘要 |
In a process for the preparation of a viscosity raising copolymer, which comprises copolymerizing at an elevated temperature (a) methacrylic acid, (b) a conjugated diolefin, and (c) an ester of an alpha , beta -ethylenically unsaturated dicarboxylic acid, an improvement is provided wherein (a) 50-60% by weight of methacrylic acid, (b) 15-49% by weight of a conjugated diolefin, and (c) 1-25% by weight of fumaric acid dialkyl ester, maleic acid dialkyl ester or a mixture thereof, wherein each alkyl is of 1-8 carbon atoms, are copolymerized in an aqueous emulsion having a phase ratio of monomer mixture:water of 1:1.7 to 1:2.5, wherein, based on the monomer content, the aqueous phase contains 0.02-1% by weight of an alkaline compound, 0.05-1% by weight of an initiator, 0.01-1% by weight of a molecular weight regulator and 0.1-5% by weight of an emulsifier.
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