| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rubber-modified styrene-based resin having excellent impact strength and transparency, especially showing the characteristics when made into a thin sheet. SOLUTION: When the weight ratio of a rubber A comprising 99-60 wt.% of a conjugated diene/1-40 wt.% of styrene is WA and that of a rubber B comprising the conjugated diene is WB, a styrene-based monomer is polymerized in a ratio wholly satisfying (1) WA:WB=(1:99)-(99:1), (2) equation Fη=WA/(WA+ WB)×Log(ηA)+WB/(WA+WB)×Log(ηB)=2.0-2.35 (ηA andηB are solution viscosities of the rubbers A and B [cP unit]) and (3) equation Fn=|nP-nA×WA /(WA+WB)-nB×WB/(WA+WB)|<=0.068 (nP, nA and nB are each refractive indexes of a polymer composed of the styrene-based monomer, the rubbers A and B) to give the objective rubber-modified styrene-based resin having (4) 1.2-5.0μm volume-average particle diameter dv of rubber and (5) 3-15 wt.% conjugated diene content WG. |
