Patent GB-1415817-A (GB)
Title: Polycarbonate graft polymer rubber compositions
IPC: C08L21/00
Filed: 1974-04-01
Abstract: 1415817 Polycarbonate/graft copolymer compositions BAYER AG 1 April 1974 [16 Nov 1973] 14390/74 Heading C3G A moulding composition comprises : (1) 70-20% by weight of at least one polycarbonate prepared by condensing polycarbonate chains on to a graft stock, said graft stock being a vinyl polymer of molecular weight 10,000- 100,000 having 3-10 side chains per macromolecule which are attached via carbon atoms, each side chain containing at least one hydroxyphenyl group; (2) 30-80% by weight of at least one graft polymer rubber obtained by graft polymerizing a mixture which comprises: (i) 50-90% by weight of styrene, α-methylstyrene, methylmethacrylate, or mixtures thereof; (ii) 10-50% by weight of acrylonitrile, methacrylonitrile, methylmethacrylate, or mixtures thereof on a diene or acrylate rubber. The polycarbonate graft stock is prepared by the radical initiated polymerization of at least one ethylenically unsaturated compound and at least one aromatic hydroxy compound copolymerizable therewith via an olefinically unsaturated substituent. The preferred ethylenically unsaturated compounds are aromatic vinyl compounds (styrene, α-methylstyrene, vinylnaphthalene); acrylic and methacrylic acid derivatives, such as the nitriles (acrylonitrile, methacrylonitrile), and C 1-6  alkyl esters (methylacrylate, methylmethacrylate, ethylacrylate, ethylmethacrylate, butylacrylate, hexylacrylate, butylmethacrylate); and vinyl esters ofaliphatic carboxylic acids (vinylacetate, vinylpropropionate). Two monomers may be used (styrene and acrylonitrile in weight ratios of from 90 : 10 to 50 : 50), or one may be used alone (methylmethacrylate). The polymerizable aromatic hydroxy compound has the formula wherein R = H or C 1 -C 4  alkyl, R 1  = H, Cl, Br, C 1 -C 4  alkyl, cycloalkyl or C 1 -C 4  alkoxy, n = 0, 1, or 2, X = OH or in an amount of 1-10 molecules per 100 molecules of total monomer quantity involved in copolymerization. Preferred aromatic hydroxy compounds are p-isopropenylphenol and 2- (hydroxyphenyl) - 2 - (p - isopropenylphenyl)- propane. The graft stock is reacted with at least one di(hydroxyphenyl)alkene (bisphenol A, tetrachlorobisphenol A and tetrabromobisphenol A) and phosgene (or other carbonic acid derivative), under conditions suitable for polycarbonate formation, such that all the hydroxyl groups of the graft stock are converted to polycarbonate chains. The graft polymer rubber component is prepared by the radical emulsion polymerization of the graft monomers in the presence of a rubber latex. The rubber may be polybutadiene, butadiene/styrene copolymer, butadiene/acrylate copolymer or polyacrylates (the term "acrylate" is defined as C 1 -C 6  alkyl esters of acrylic and methacrylic acids), and may include up to 10% by weight of at least one other monomer (methylacrylamide, methacrylamidomethylol ether, acrylic acid, divinylbenzene and ethylene glycol dimethacrylate). 10-200 parts by weight monomers are grafted with 100 parts by weight rubber. The term "graft polymer rubber" includes monomers grafted on to the rubber plus resinous polymers obtained by copolymerization of the grafting monomers. The mixture should have a rubber content of 5-40% by weight, and sufficient monomer should be grafted on to the rubber to render the grafted rubber compatible with the resinous copolymers. Preferred graft polymer rubber compositions comprise (1) 10-100% by weight of a graft polymer of 10-90 parts by weight of a monomer mixture of 50-90% by weight of styrene and 50-10% by weight of acrylonitrile on 90-10 parts by weight of polybutadiene, butadiene/acrylonitrile copolymer (optionally containing up to 10% by weight of methacrylic acid and/or divinylbenzene) or polybutylacrylate (optionally containing up to 10% by weight methacrylamidomethylol ether); (2) 0-90% by weight of a resin-like copolymer of 50-90% by weight of styrene and 50-10% by weight of acrylonitrile. The compositions may comprise fillers, glass fibres, pigments, stabilizers, flame-retarding agents, fluidizing agents and/or lubricants, and are prepared by mixing the components using rolling mills, internal kneaders or double shaft extruders. Moulded articles may be prepared (especially by injection moulding processes).