Patent GB-1482766-A (GB)
Title: Method for preparation of abs type resins
IPC: C08F279/00
Filed: 1974-12-20
Abstract: 1482766 Graft polymer blends MONSANTO CO 20 Dec 1974 [26 Dec 1973] 55085/74 Heading C3G A process for the production of a polymer blend comprising particles of an alkadiene elastomer graft polymerized with a mono (substituted or unsubstituted vinyl) aromatic monomer and an alkenenitrile monomer dispersed in a matrix copolymer of a mono (substituted or unsubstituted vinyl) aromatic monomer and an alkenenitrile monomer comprises: (a) mixing, with a rubber latex prepared by emulsion graft polymerizing in an aqueous medium an alkalidene elastomer with a mono (substituted or unsubstituted vinyl) aromatic monomer and an alkenenitrile monomer, 20- 400 parts by weight per 100 parts by weight of latex solids of a mixture of (i) at least one monoethylenically unsaturated monomer, selected from a mono (substituted or unsubstituted vinyl) aromatic monomer and an alkenenitrile monomer and (ii) at least one saturated organic solvent for styrene/acrylonitrile copolymer boiling at a temperature of 25-250 C. at atmospheric pressure, the mixture comprising at least 5 parts by weight of the saturated organic solvent but not more than 50 parts by weight of the mono (substituted or unsubstituted vinyl) aromatic monomer per 100 parts of solvent and monomers by weight; (b) extracting the graft rubber latex into the mixture of monoethylenically unsaturated monomer and saturated organic solvent to form a dispersion phase therein and a separate aqueous phase; (c) separating the aqueous phase from the dispersion phase; and (d) subjecting the dispersion of graft rubber in the mixture of unsaturated monomer and saturated organic solvent to mass polymerization conditions, thereby producing a polymer blend comprising graft alkadiene rubber dispersed in a matrix copolymer of mono (substituted or unsubstituted vinyl) aromatic monomer and an alkenenitrile monomer. Preferred alkaliene rubbers are monopolymers of butadiene, isoprene, piperylene, and chloroprene and copolymers thereof with monoethylenically unsaturated monomers. The unsaturated monomer to be mixed with the graft polymer is preferably styrene and/or acrylonitrile. Numerous saturated organic solvents are specified in the description. The mixing and extraction step (b) may be carried out at 0-160 C. The graft rubber latex may be coagulated prior to extraction into the mixture of monoethylenically unsaturated monomer and saturated organic solvent. The organic phase which results from the extraction of graft rubber and the separation of the free water phase comprises a dispersion of graft rubber copolymer particles in the monomer-solvent mixture. Prior to the mass polymerization step which is carried out conventionally, e.g. under heat at 130-200 C. further monomers such as styrene or acrylonitrile may be added. The mass polymerization may be continuous and the product obtained thereby may be subjected to devolatilisation, the volatile fraction separated being recycled to form at least part of the mixture of monoethylenically unsaturated monomer and solvent. The aqueous phase may be effected mechanicaally with applied pressure, e.g. in a screw separator. In the specific examples the process is carried out on a butadiene-styrene rubber grafted with styrene-acrylonitrile mixed with: styrene and acetonitrile as solvent (IA) (IB); styrene and acrylonitride and acetone (II); acrylonitrile and a solvent selected from propionitrile, acetone, cyanohydrin, hydroxyethyl acetate, propylene carbonate, butyronitrile, benzonitrile, ethyl acetate, #-methoxy propionitrile, dimethyl formamide, toluene, acetonitrile, and chloroform (III). In Example IV the same grafted rubber is mixed with styrene and acrylonitrile and a solvent selected from propionitrile, butyronitrile, #-methoxy propionitrile and methyl ethyl ketone, the latex formed being coagulated with aluminium sulsulphate whilst Examples V to VII describe processes in which there is further addition of styrene and acrylonitrile monomers.