GB971044A - Process for conditioning organic pigments - Google Patents

Abstract

Organic pigments are conditioned by grinding them in an aqueous grinding medium in the presence of an organic compound which is solid, which is soluble to the extent of not more than 5 parts by weight in 100 parts by weight of water at room temperature and which is capable of being removed by sublimation or by distillation with steam, or of a mixture of such organic compounds, and then separating the pigment from the grinding medium. Organic compounds mentioned are hexachlorethane, naphthalene, diphenyl, p-dichlorobenzene, hexachlorobenzene, phthalic anhydride, b -hexachlorocyclohexane, hexamethylethane, hexabromethane, chloranil and camphor. The aqueous medium may contain besides water, methanol, ethanol, isopropanol, phenol, cresol acetone, methyl ethyl ketone cyclohexanone, acetic acid, benzoic acid, phthalic acid or an ester thereof, methane sulphonic acid, benzene sulphonic acid, naphthalene sulphonic acid, pyridine, ethanolamine, stearic acid, resin acids, resin acid esters such as dihydroabietic acid esters of paraffin oil. The conditioned a -forms of copper phthalocyanine, copper phthalocyanine containing one or two atoms of chlorine or bromine and metal-free phthalocyanine are made by grinding a ratio of one part of the crude a - or b -forms at 5 DEG to 30 DEG C. with at most three parts of an aliphatic organic compound such as hexachlorethane and optionally in the presence of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, glyoxal, paraformaldehyde, metaldehyde, paraldehyde, hexamethylene tetramine, urea, formamide, dimethylformamide, acetamide or urotropin. Alternatively the pigment may be treated with the aldehyde or amide after the grinding is completed. The conditioned b -form of the phthalocyanines are made by grinding the crude b -forms (a) using as organic compound an aromatic hydrocarbon or a halogenated aromatic hydrocarbon, or (b) using a ratio of at least three parts of hexachlorethane per part of pigment, or (c) using hexachlorethane at a temperature above 40 DEG C., or (d) using hexachlorethane together with naphthalene or a phenol. In examples pigments are conditioned of the phthalocyanine, disazo, dioxazine, nitro, quinacridone, indigo, thioindigo, naphthalic acid di-benzimidazole, perylene tetracarboxylic acid diimide, dianthraquinoryl, isoviolanthrone, flavanthrone, indanthrone and di-(pyrazoleanthronyl) series.ALSO:Organic pigments are conditioned by grinding them in an aqueous grinding medium in the presence of an organic compound which is solid, which is soluble to the extent of not more than 5 parts by weight in 100 parts by weight of water at room temperature and which is capable of being removed by sublimation or by distillation with steam, or of a mixture of such organic compounds, and then separating the pigment from the grinding medium. Organic compounds mentioned are hexachlorethane, naphthalene, diphenyl, p-dichlorobenzene, hexachlorobenzene, phthalic anhydride, b -hexachlorocyclohexane, hexamethylethane, hexabromethane, chloranil and camphor. The aqueous medium may contain besides water, methanol, ethanol, isopropanol, phenol, cresol, acetone, methyl ethyl ketone, cyclohexanone, acetic acid, benzoic acid, phthalic acid or an ester thereof, methane sulphonic acid, benzene sulphonic acid, naphthalene sulphonic acid, pyridine, ethanolamine, stearic acid, resin acids, resin acid esters such as dihydroabietic acid esters or paraffin oil. The conditioned a -forms of copper phthalocyanine, copper phthalocyanine containing one or two atoms of chlorine or bromine and metal free phthalocyanine are made by grinding a ratio of one part of the crude a - or b -forms at 5-30 DEG C. with at most three parts of an aliphatic organic compound such as hexachlorethane and optionally in the presence of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, glyoxal, paraformaldehyde, metaldehyde, paraldehyde, hexamethylene tetramine, urea, formamide, dimethylformamide, acetamide or urotropin. Alternatively the pigment may be treated with the aldehyde or amide after the grinding is completed. The conditioned b -form of the phthalocyanines are made by grinding the crude b -forms (a) using as organic compound an aromatic hydrocarbon or a halogenated aromatic hydrocarbon or (b) using a ratio of at least three parts of hexachlorethane per part of pigment or (c) using hexachlorethane at a temperature above 40 DEG C. or (d) using hexachlorethane together with naphthalene or a phenol. In examples, pigments are conditioned of the phthalocyanine, disazo, dioxazine, nitro, quinacridone, indigo, thioindigo, naphthalic acid di-benzimidazole, perylene tetracarboxylic acid diimide, dianthraquinonyl, isoviolanthrone, flavanthrone, indanthrone and di-(pyrazoleanthronyl) series.