| 摘要 |
A multistage core-shell particle consisting of a core, a first shell and optionally a second shell, substantially free from vinylically unsaturated compounds having at least two equally reactive double bonds, wherein: (i) the core contains a first (meth)acrylic polymer; (ii) the first shell contains a low Tg polymer comprising 0 to 25 % by weight of a styrenic monomer and 75 to 100 % by weight of a (meth)acrylic monomer, the (meth)acrylic monomer capable of forming a homopolymer having a glass transition temperature (Tg) in the range from -75 to -5 ~C, and which first shell represents more than 65 % by volume of the combined volume of the core and first shell; (iii) the second shell, when present, contains a second (meth)acrylic polymer which may be the same or different from the first (meth)acrylic polymer; and (iv) the core and first shell together contain from 0.5 to 1.0 % by weight of a graftcrosslinker. A composition and a polysiloxane-free moulded article containing residues obtainable from such core-shell particles. A method of forming a moulding article having improved impact resistance using an impact modifier formed from such core-shell particles. |
