| 摘要 |
PURPOSE:To provide the title compsn. which has such properties that tan delta is large and a dynamic-to-static modulus ratio is low and is excellent in vibration insulation properties, deterioration resistance and physical properties as a rubber, consisting of a chloroprene copolymer and a liquid chloroprene copolymer obtd. by copolymerizing a specific mixture in the presence of a xanthogen disulfide compd. CONSTITUTION:90-60% (by weight; the same applies hereinbelow) 2-chlorobutadiene-1,3 (a) is polymerized with 10-40% unsaturated nitrile (b) [e.g., (meth)acrylonitrile] and 0-15% copolymerizable monomer (c) (e.g., 1-chlorobutadiene-1,3) at 30-50 deg.C to a conversion of the monomers of 50-80%, thus obtaining a chloroprene copolymer (A) having a number-average MW of 50,000-350,000. A mixture of 1-10% polyfunctional (meth)acrylate (d) having at least two unsaturated double bonds per molecule, 2-15% 2,3-dichlorobutadiene-1,3 (e) and 75-97% component (a) is copolymerized in the presence of a xanthogen disulfide compd. (f) of the formula (wherein R is a 1-12C hydrocarbon group) to obtain a liquid chloroprene copolymer (B) having a number-average MW of 500-20,000 and a toluene-insoluble matter. The component A is blended with the component B.
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