| 摘要 |
PROBLEM TO BE SOLVED: To achieve an excellent low-temperature impact strength by dispersing a polybutadiene rubber having a specified molecular weight, a specified polydispersity index and a specified cis-1,4-structure content in an aromatic vinyl resin. SOLUTION: A polybutadiene rubber having a bimodal molecular weight distribution curve (as determined by GPC) in which the peak top molecular weights of the high-molecular-weight and low-molecular-weight components are 100,000-1,500,000 and 10,000-50,000, respectively and having a polydispersity index of 4.5-14.5 and a cis-1,4-structure content of 80wt.% or above is dissolved in an aromatic vinyl monomer (e.g. styrene). After the addition of a chain transfer agent and an organic peroxide catalyst, the obtained solution is subjected to polymerization at 20-200 deg.C to a conversion of 30-50%. The polymerization solution is suspended in water containing a suspending stabilizer and subjected to polymerization. The product is filtered, and the cake is washed with water and dried to obtain a high-impact strength aromatic vinyl resin composition composed of the resin matrix and polybutadiene particles having a mean particle diameter of 0.01-10μdispersed therein.
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