High gloss high impact monovinylidene aromatic polymers

A rubber modified monovinylidene aromatic polymer having a bimodal particle size distribution comprising:

• a) rubber particles of a star or branched low viscosity rubber, having a solution viscosity (5 percent in styrene at 20° C.) of from 20 to 120 centipoise and a Mooney viscosity (ML+1 at 100° C.) of from 30 to 80 centipoise, a volume average particle size of from 0.1 to 2μ, an average monovinylidene aromatic polymer to rubber occlusion content of from 3.1 to 6, and a cellular or core shell morphology or mixture thereof, and
• b) rubber particles of a star or branched low viscosity rubber, linear diene rubber or block copolymer rubber having a solution viscosity (5 per cent in styrene at 20° C.) of from 20 to 120 centipoise and a Mooney viscosity (ML+1 at 100° C.) of from 30 to 80 centipoise, a volume average particle size of from 0.5 to 10μ, characterized in that the rubber particles of b) are more dense than the particles of a), having an average monovinylidene aromatic polymer to rubber occlusion content of 0.5 to 3,
• wherein the particles of a) are from 50 to 99 wt. % of the total diene rubber content.