Patent GB-686269-A (GB)
Title: Manufacture and use of pigment preparations
IPC: C09B67/08
Filed: 1950-08-04
Abstract: Compositions comprising a pigment and a carboxylated vinyl ester polymer, i.e. a vinyl ester polymer containing carboxyl groups and which is soluble in alkalies but insoluble in water as the free acid and which can be kneaded while hot and is a solid at room temperature, are made by precipitating from an aqueous suspension comprising the pigment and a dissolved water-soluble salt of the polymer, e.g. an alkali metal, ammonium or amine salt and optionally a dispersing agent, a mixture of the pigment and polymer as the free acid and/or a water insoluble salt thereof, by treating the suspension with an acid, e.g. hydrochloric, formic or sulphuric acid and/or a salt which forms with the polymer an insoluble salt, e.g. calcium chloride.  The precipitate is preferably purified by washing with water, with kneading, at raised temperatures and subsequently dried.  Specified polymers are copolymers of (1) vinyl acetate and crotonic acid; (2) vinyl acetate and maleic acid mono-methyl ester; (3) vinyl acetate, vinyl chloride and crotonic acid; (4) vinyl acetate, vinyl benzoate and crotonic acid; (5) vinyl acetate, ethyl acrylate and crotonic acid; partially hydrolysed polyvinyl acetate after-treated with phthalic anhydride and partially hydrolysed polyvinyl acetate after-treated with maleic anhydride.  Pigments mentioned are the diazotized product of 2-methyl-4-chloro-1-aminobenzene and 1-(21-oxy-31-naphthoyl)-amino-2-methyl-4-chlorobenzene, the diazotized product of 2 : 5-dichloro-1-aminobenzene and 1-(21-oxy-31 - naphthoyl) - amino - 2 : 5 - dimethoxybenzene, copper phthalocyanine, Cibanone Blue, the diazotized product of o-nitro-p-toluidine and acetoacetic acid anilide, and indigo. Dispersing agents which may be used are sulphite cellulose waste liquor or sodium dinaphthyl methane disulphonate.  The pigment composition may be used (1) in the production of cellulose acetate artificial silk, e.g. in admixture with acetone, acetyl cellulose, lactic acid ethyl ester and paraffin oil; (2) in admixture with nylon in the production of coloured fibres; (3) for colouring masses used in injection moulding; (4) for colouring coating lacquers, e.g. in admixture with dammar resin and alcohol; (5) in the production of coloured sheets and foils, e.g. from a mixture of the pigment composition, acetyl cellulose, dimethyl glycol phthalate and acetone, or from a mixture of the pigment composition, polyvinyl chloride and dioctyl phthalate.  Examples describe: (1) a copolymer of vinyl acetate, vinyl chloride and crotonic acid made by polymerizing a solution of the monomers in acetone in the presence of benzoyl peroxide; (2) a copolymer of vinyl acetate, vinyl benzoate and crotonic acid made by polymerizing a solution of the monomers in propanol and water in the presence of benzoyl peroxide, the latter ingredient being added stepwise, and the preparation of its ammonium salt; (3) a copolymer of vinyl acetate, ethyl acrylate and crotonic acid and the ammonium salt thereof, under conditions similar to (2); (4) the partial hydrolysis of polyvinyl acetate and the after-treatment thereof with phthalic anhydride; and (5) the partial hydrolysis of polyvinyl acetate and the after-treatment thereof with maleic anhydride.