To provide a transparent rubber-modified polystyrene-based resin having excellent transparency and resistance to environmental stress-cracking, while keeping impact resistance.
This transparent rubber-modified polystyrene-based resin is composed of rubber particles (A) comprising a rubbery copolymer as a dispersed phase and a copolymer (B) as a continuous phase, wherein the copolymer (B) is obtained by copolymerizing (i-1) a styrene-based monomer in an amount of 20-70 pts.wt., (i-2) an (meth)acrylic acid ester-based monomer in an amount of 30-80 pts.wt., (i-3) another polymerizable monomer in an amount of 0-40 pts.wt., and a polyfunctional maleimide-based monomer in an amount of 0.0005-1.0 pt.wt. based on 100 pts.wt. of the monomers (i-1), (i-2), and (i-3) in total, a residue content of the polyfunctional maleimide-based monomer in the resin is not more than 80 ppm, a difference of refractive indexes between the copolymer (B) and the rubber particles (A) is not more than 0.01, and a rubber content in the transparent rubber-modified polystyrene-based resin is 1-40 wt%.
Takahiko Mizobe
Kiyoharu Nishiyama