GB1350284A - Polymeric pigment dispersants - Google Patents

Abstract

1350284 Polymeric dispersants for organic pigments IMPERIAL CHEMICAL INDUSTRIES OF AUSTRALIA & NEW ZEALAND Ltd 6 May 1971 [14 May 1970] 13473/71 Heading C3P A polymeric dispersant for dispersing an organic pigment in an organic liquid medium, comprises a backbone chain having incorporated in it or dependent from it one or more solubilizing groups such as a C 8 -C 20 alkyl group, and one or more ionic groups, which are groups which are already charged, or are capable of forming an ion, said ionic group being in the form of a salt with a salt-forming component which is a substance capable of forming a salt with the ionic group, and having an affinity for the surface of the organic pigment particles; the polymer must contain 99-50 mol per cent of the solubilizing group-containing units, and 1-50 mol per cent of the ionic group containing units. The solubilizing group is one which is solvatable by the organic liquid, such as 2-ethyl hexyl, dodecyl, stearyl or phenyl for saturated hydrocarbons, and polyethers for alcoholic solvents. Suitable ionic groups (as defined) are carboxylic acid, sulphonic acid or phosphoric acid groups or their salts, primary-, seoondary- and tertiary amino groups, quaternary ammonium groups, phosphonium and sulphonium groups. The salt-forming components vary widely, and may be for example a pigment modified with an ionic compound which contains any of the ionic groups listed above, an ionic intermediate in the manufacture of the pigment or, in the case of "rosinated pigments", substances such as dehydroabietic acid, abietic acid, cholic acid, desoxycholic acid, cholanic acid and 12-keto cholanic acid. Also, for toners and lake pigments, suitable salt forming components are naphthalene sulphonic acids, anthracene and phenanthrene sulphonic acids, benzene sulphonic acids and formaldehyde condensates of naphthalene-2-sulphonic acid. Preferred polymers are addition polymers. In the examples, copolymers of dimethylamino ethyl methacrylate and 2-ethyl hexyl aorylate in which the amino groups are quaternized with benzyl chloride or, in Example 2 only, dimethyl sulphate, a copolymer of 2-methyl thio acrylate, 2-ethylhexylacrylate and methacrylic acid, reacted with dimethyl sulphate, and a copolymer of allyltriphenyl phosphonium bromide and 2-ethyl hexyl acrylate, are reacted with salt forming components which are selected from rosin, cholic acid, formaldehyde condensation product of naphthalene sulphonic acid, polymerized rosin, hydrogenated polymerized rosin, sulphonated copper phthalocyanine paste, the sodium salt of the coupling product of the diazo salt of 2-chloro-4-aminotoluene-5 sulphonic acid and 2-hydroxy naphthalene-3- carboxylic acid, the coupling product of the diazo salt of 3,3<SP>1</SP>-dichloro-benzidine with sodium acetoaoetanilide para sulphonate, and an ionic pigment of C.I. number 23900. These are then used as dispersants for various organic pigments in media such as toluene, and "Boralene" (Trade Marked petroleum distillate solvent) mixed with a small amount of water.