| 摘要 |
<p>Copolymers of vinyl aromatic, ethylenically unsaturated nitrile and, optionally, methyl methacrylate monomers, have an impact modifier comprising a) large grafted rubber particles of a rubbery alkyl acrylate polymer having a particle size from 0.5 mu m to 0.8 mu m, 0.04 to 0.5 percent by weight of a polymerized crosslinking monomer and from 0.5 to 40 percent grafted rigid phase, and b) small grafted rubber particles of a rubbery alkyl acrylate polymer having a particle size from 0.05 mu m ro 0.20 mu m, 0.25 to 2.0 percent of a crosslinking monomer and from 15 to 60 percent by weight grafted rigid phase. The weight percentage of crosslinking monomer is at least twice the weight percentage of the crosslinking monomer in the large particle, and the weight ratio of large to small rubber particles is 5-80/95-20.</p> |
