| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new polystyrene-based resin composition giving a grafted rubber having a sufficiently low glass transition point and a high graft rate by using a polybutadiene having a specific structure as a rubbery polymer. SOLUTION: This polystyrene-based resin composition comprising a styrenic monomer, an unsaturated nitrile-based monomer and a rubbery polymer is characterized in that the rubbery polymer is a modified polybutadiene obtained by modifying a raw material polybutadiene having the following characteristics with a transition metal catalyst. The characteristics of the raw material polybutadiene: (1) the butadiene monomer units comprise 4 to 30 mol.% of 1,2-structure units, 65 to 95 mol.% of cis-1,4-structure units, and <=5 mol.% of trans-1,4-structure units; and (2) the ratio (Tcp/ ML1+4 ) of a toluene solution viscosity (Tcp) to a Mooney viscosity (ML1+4 ) at 100 deg.C is >=2.5.
|
