Patent GB-801522-A (GB)
Title: Manufacture of pigment dispersions
IPC: C09C3/00
Filed: 1954-09-10
Abstract: Aqueous pigment (e.g. carbon black, azo-, phthalocyanine-, and other pigment dyes) dispersions are prepared by kneading a hydrous pigment or pigment-dye press cake with an acid resin in neutral or acid medium, the resin being kneadable at room temperature or being rendered kneadable by the application of heat, until a good blend is obtained, eliminating the separated water and treating the pigment dye preparation obtained by a change of phase, with an aqueous alkaline liquid, preferably aqueous ammonia.  In an example an aqueous press cake of carbon black is kneaded with a polyacrylonitrile which has been 80 per cent hydrolysed, water is separated and the carbon black resin phase dissolved in aqueous ammonia.  Other acidic natural or synthetic resins may be used, e.g. shellac, copolymers of vinyl esters with unsaturated acids, incompletely condensed alkyd resins or polyamides.ALSO:Aqueous pigment dispersions are prepared by kneading a hydrous pigment or pigment dye press cake with an acid resin in neutral or acid medium, the resin being kneadable at room temperature or being rendered kneadable by the application of heat, until a good blend is obtained, eliminating the separated water and treating the pigment dye preparation obtained by a change of phase, with an aqueous alkaline liquid, preferably aqueous ammonia.  The term "acid resin" is defined as a resin having free carboxylic acid groups enabling it to be dissolved in alkali so that pigment dispersions may be obtained which contain only pigment dyestuff particles in the dispersed phase and in the dispersion medium a solution of a salt os the resin.  Specified resins include copolymerf of vinyl acetate or propionate or chloride with acids such as maleic, fumaric, crotonic, acrylic, methacrylic or cinnamic acid; a copolymer of vinyl butyl ether and maleic anhydride; hydrolysis products of polymers containing ester, nitrile or acid anhydride groups; incompletely condensed resins of polybasic acids and polyhydric alcohols or polyamines; and shellac.  Specified alkalies are sodium and potassium hydroxides and carbonates, sodium and ammonium bicarbonates, borax, ethylene diamine and di- or tri-ethanolamine.  Any pigment insensitive to acids or alkalies may be used such as mono- or dis-azo, vat and phthalocyanine dyestuffs and carbon black (see Group III).  In examples: (1) an aqueous press cake of Hansa Yellow G is kneaded with the resin obtained by condensing 1.2 mols. of phthalic acid with 1 mol. of hexane-triol-(1 : 3 : 5), water is eliminated, the pigment-resin phase is kneaded further with aqueous ammonia and then water is added to give an aqueous dispersion; (2) as in (1) using Indanthrene Red Violet RH and a mixture of the resins obtained by copolymerizing crotonic acid with vinylacetate and propionate; (3) as in (1) using the azo dyestuff 1-amino-2-methyl-4-chlorobenzene --> 1 - (21:31 - hydroxynaphthoylamino) - 2 - methyl - 4 - chlorobenzene, a copolymer of vinyl acetate and crotonic acid and aqueous sodium hydroxide; (4) as in (1) using the azo dyestuff 4-nitro-2-aminotoluene --> 1 - (21:31 - hydroxynaphtholyamino) - 4 - chlorobenzene, shellac and aqueous borax, sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia; (5) as in (1) using the disazo dyestuff 3:31-dichlorobenzidine (1 mol.) --> acetoacetanilide (2 mols.), a copolymer of vinyl butyl ether and maleic anhydride and aqueous sodium carbonate or sodium hydroxide; (6) as in (1) using copper phthalocyanine, the esterification product of 1 mol. of methanol with the copolymer of 1 mol. of maleic anhydride and 1 mol. of vinyl butyl ether and ammonia or ammonium carbonate; (7) as in (1) using tetradecachloro-copper phthalocyanine, a copolymer of 7 mols. of ethyl acrylate and 3 mols. of acrylic acid and potassium carbonate or hydroxide; (8) as in (1) using carbon black, a polyacrylonitrile which has been 80 per cent hydrolysed and ammonia; (9) as in (1) using the azo dyestuff 2-chloro-4-nitroaniline --> 2-naphthol, the condensation product of 1:2 mols. of phthalic anhydride and 1 mol. of hexanetriol-(1 : 3 : 5).ALSO:Aqueous pigment dispersions are prepared by kneading a hydrous pigment or pigment dye press cake with an acid resin in neutral or acid medium, the resin being kneadable at room temperature or being rendered kneadable by the application of heat, until a good blend is obtained, eliminating the separated water and treating the pigment dye preparation obtained by a change of phase, with an aqueous alkaline liquid, preferably aqueous ammonia.  The term "acid resin" is defined as a resin having free carboxylic acid groups enabling it to be dissolved in alkali so that pigment dispersions may be obtained which contain only pigment dyestuff particles in the dispersed phase and in the dispersion medium a solution of a salt of the resin.  Specified resins include copolymers of vinyl acetate or propionate or chloride with acids such as maleic, fumaric, crotonic, acrylic, methacrylic or cinnamic acid; a copolymer of vinyl butyl ether and maleic anhydride; hydrolysis products of polymers containing ester, nitrile or acid anhydride groups; incompletely condensed resins of polybasic acids and polyhydric alcohols or polyamines; and shellac.  Specified alkalies are sodium and potassium hydroxides and carbonates, sodium and ammonium bicarbonates, borax, ethylene diamine and di- or tri-ethanolamine.  Any pigment insensitive to acids or alkalies may be used such as mono- or dis-azo, vat and phthalocyanine dyestuffs and carbon black (see Group III).  In examples: (1) an aqueous press cake of Hansa Yellow G is kneaded with the resin obtained by condensing 1.2 mols. of phthalic acid with 1 mol. of hexane-triol-(1 : 3 : 5), water is eliminated, the pigment-resin phase is kneaded further with aqueous ammonia and then water is added to give an aqueous dispersion; (2) as in (1) using Indanthrene Red Violet RH and a mixture of the resins obtained by copolymerizing crotonic acid with vinylacetate and propionate; (3) as in (1) using the azo dyestuff 1-amino-2-methyl-4-chlorobenzene --> 1 - (21 : 31 - hydroxynaphthoylamino) - 2-methyl-4-chlorobenzene, a copolymer of vinyl acetate and crotonic acid and aqueous sodium hydroxide; (4) as in (1) using the azo dyestuff 4 - nitro - 2 - aminotoluene --> 1 - (21 : 31-hydroxynaphthoylamino) - 4 - chlorobenzene, shellac and aqueous borax, sodium hydroxide, sodium carbonate, sodium or carbonate, ammonium carbonate, ammonium bicarbonate or ammonia; (5) as in (1) using the disazo dyestuff 3 : 31 - dichlorobenzidine (1 mol.) \sQ acetoacetanilide (2 mols.), a copolymer of vinyl butyl ether and maleic anhydride and aqueous sodium carbonate or sodium hydroxide; (6) as in (1) using copper phthalocyanine, the product of esterification of 1 mol. of methanol with the copolymer of 1 mol. of maleic anhydride and 1 mol. of vinyl butyl ether and ammonia or ammonium carbonate; (7) as in (1) using tetradecachlora-copper phthalocyanine, a copolymer of 7 mols. of ethyl acrylate and 3 mols. of acrylic acid and potassium carbonate or hydroxide; (9) as in (1) using the azo dyestuff 2-chloro - 4 - nitroaniline --> 2 - naphthol, the condensation product of 1 : 2 mols. of phthalic anhydride and 1 mol. of hexane-triol-(1 : 3 : 5).