Patent GB-758986-A (GB)
Title: Improvements in or relating to aqueous dispersions of pigments
IPC: C09D17/00
Filed: 1954-07-28
Abstract: Inorganic pigments are dispersed in water with 0.05 to 3 per cent of a water-soluble salt of a homogeneous copolymer of maleic anhydride and an unsaturated hydrocarbon having only one active olefinic linkage and containing five to ten carbon atoms, said copolymer having a molecular weight below 5000, a viscosity less than 1000 c.p.s. at 25 DEG  C. in 35 per cent solution in dioxane or methyl ethyl ketone, and the salt thereof giving a pH in water of at least 4.5.  Unsaturated hydrocarbons specified are diisobutylene, amylene, isoamylene, hexene, decene, styrene, a -methylstyrene, vinyltoluene, isopropenyltoluene, indene, dicyclopentadiene and terpenes such as b -pinene and limonene. Salts described are those derived from alkali metal, ammonium, quaternary ammonium and amine bases.  The pigments may be calcium and/or magnesium carbonate; barium sulphate; zinc, chromium and lead oxides; mica, talc, white lead, silica, china clay, rutile, anatase, blanc fixe, kaolin, lithopone and mixtures and also included may be insoluble colours such as iron oxide, cadmium sulphide, toluidine red, lithol toner, chrome orange or yellow or green, "Mansa" (Registered Trade Mark) yellow and phthalocyanine green or blue.  The dispersions may contain up to 85 per cent pigment and wetting agents such as sulphated alcohols, sulphonated alkylbenzenes, sodium alkylphenoxypolyethoxyethyl sulphonate and alkylphenoxypolyethoxyethanols, are optional additives.  In examples diethylene glycol and an antifoamer are also included. The dispersions find application in water-base coating compositions, such as paints and enamels, and may be added to copolymer latices, e.g. those of copolymers of styrene with butadiene, vinyl acetate and acrylic compounds.ALSO:Aqueous dispersions of inorganic pigments contain as dispersing agent a water soluble salt of homogenous copolymer of maleic anhydride and an unsaturated hydrocarbon having only one active olefinic linkage and containing 5 to 10 carbon atoms, said copolymer having a molecular weight below 5000, a viscosity less than 1000 cps. at 25 DEG C. in 35 per cent solution in dioxane of methyl ethyl ketone, and the salt thereof giving a pH in water of at least 4.5.  Unsaturated hydrocarbons specified are diisobutylene, amylene, isoamylene, hexene, decene, styrene, a-methylstyrene, vinyltoluene, isopropenyl toluene, indene, dicyclopentadiene and terpenes such as b -pinene and limonene. Salts disclosed are those derived from alkali metal, ammonium, quaternary ammonium and amine bases and the amount of salt used in the dispersion is from 0.05 to 3 per cent by weight of the pigments.  Pigments specified are calcium and magnesium carbonates; barium sulphate; zinc, chrome and lead oxides; mica, talc, white lead, silica, china clay, rutile, anatase, blanc fixe, kaolin, lithopone and mixtures and also present may be unsoluble colours such as iron oxide, cadmium sulphide, toluidine red, lithol toner, chrome orange or yellow or green, "Hanso" (Registered Trade Mark) yellow and phthalocyanine green or blue. The dispersions, optionally containing wetting agents, may contain up to 85 per cent of pigment and are useful in paints and enamels.