Impact-modified compositions

摘要

In one of its aspects the invention is directed to rubber modified thermoplastic resin compositions comprising discontinuous elastomeric phase particles derived from a unitary rubber substrate having at least a bimodal particle size distribution, wherein the elastomeric phase particles comprise a polymer having structural units derived from at least one (C₁-C₁₂)alkyl(meth)acrylate monomer and are dispersed in a rigid thermoplastic phase, wherein at least a portion of the rigid thermoplastic phase is grafted as a shell to elastomeric phase core particles, and wherein the rigid thermoplastic phase comprises structural units derived from at least one vinyl aromatic monomer, at least one monoethylenically unsaturated nitrile monomer and at least one (C₁-C₁₂)alkyl- or aryl-(meth)acrylate monomer. In another aspect the rigid thermoplastic phase of the compositions comprises a first thermoplastic phase at least a portion of which is grafted to the elastomeric phase; and a second thermoplastic phase comprising a polymer prepared separately in the absence of elastomeric phase and added to the composition.