| 摘要 |
PURPOSE:A rubber-modified styrene resin of good balance between impact resistance and rigidity, obtained by polymerizing a styrene monomer containing a specified polybutadiene rubber as a toughening agent. CONSTITUTION:A solution formed by dissolving 4-15wt% star polybutadiene rubber (preferably, one containing 10-40mol% 1,2-vinyl structure) to which at least 50wt% five polymer chains are bonded in 85-96wt% styrene monomer is polymerized. As the polymerization system, a bulk, solution or bulk/suspension polymerization process is advantageous. For example, a styrene monomer in which polybutadiene is dissolved is bulk-polymerized in the presence of a catalyst such as a peroxide and the polymerization solution at the time of a conversion of about 20-40% is suspended in water and completely polymerized. The rubber-modified styrene resin obtained in this way has both, excellent strength and excellent rigidity. |
