Impact-modified compositions

A rubber modified thermoplastic resin composition comprising about 20 to about 94 wt. % based on the total weight of the resin composition of 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 butyl acrylate and are dispersed in a rigid thermoplastic phase, wherein the unitary rubber substrate comprises a first mean particle size of less than about 160 nm and a second mean particle size in a range of between about 200 nm and about 750 nm, wherein at least a portion of the rigid thermoplastic phase is grafted as a shell to elastomeric phase core particles, and wherein the thermoplastic phase comprises structural units derived from methyl methacrylate and either styrene and acrylonitrile, or alpha-methyl styrene and acrylonitrile or a mixture of styrene, alpha-methyl styrene and acrylonitrile.

A rubber modified thermoplastic resin composition comprising a discontinuous elastomeric phase dispersed in a rigid thermoplastic phase, wherein the elastomeric phase comprises particles comprising a polymer having structural units derived from at least one (C1-C12)alkyl(meth)acrylate monomer and further comprises less than about 1 weight % of structural units derived from polymerization of monoethylenically unsaturated carboxylic acids, and wherein the rigid thermoplastic phase comprises a first thermoplastic phase at least a portion of which is grafted as a shell to elastomeric phase core particles;

• and a second thermoplastic phase comprising a polymer prepared separately in the absence of elastomeric phase and subsequently added to the composition, wherein the first 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;
• and wherein the polymer of the second thermoplastic phase comprises structural units derived from at least one vinyl aromatic monomer and at least one monoethylenically unsaturated nitrile monomer.

A rubber modified thermoplastic resin composition comprising a discontinuous elastomeric phase dispersed in a rigid thermoplastic phase, wherein the elastomeric phase comprises particles comprising a polymer having structural units derived from butyl acrylate and wherein the rigid thermoplastic phase comprises a first thermoplastic phase at least a portion of which is grafted as a shell to elastomeric phase core particles, and a second thermoplastic phase comprising a polymer prepared separately in the absence of elastomeric phase and added to the composition, wherein the first thermoplastic phase comprises structural units derived from methyl methacrylate and either styrene and acrylonitrile, or alpha-methyl styrene and acrylonitrile or a mixture of styrene, alpha-methyl styrene and acrylonitrile;

• wherein the second thermoplastic phase comprises a polymer having structural units derived from either styrene and acrylonitrile, or alpha-methyl styrene and acrylonitrile or a mixture of styrene, alpha-methyl styrene and acrylonitrile;
• and wherein the elastomeric phase comprises less than about 1 weight % of structural units derived from polymerization of monoethylenically unsaturated carboxylic acids.