Patent GB-374437-A (GB)
Title: Improvements in or relating to the production of finely divided material
IPC: C09C3/00
Filed: 1931-02-03
Abstract: In grinding or milling insoluble or difficultly soluble dyestuffs or pigments in aqueous media, frothing is prevented by the addition of an organic liquid having a low surface tension relative to that of water.  Suitable organic liquids are alcohols, e.g. methyl, ethyl, and butyl alcohols, ethers, e.g. ethyl ethers, esters, e.g. ethyl acetate, ketones, e.g. acetone, and aromatic, hydroaromatic or aliphatic hydrocarbons, e.g. benzene or paraffin oil.  The grinding may be carried out in the presence of additional abrasive materials, which may be water-soluble to facilitate their removal from the finely divided material. Examples of such abrasives are boric acid and sodium chloride; thus an insoluble dyestuff may be ground with sodium chloride in the presence of a saturated solution of sodium chloride to which methylated spirits has been added to prevent frothing.  The grinding may also be effected in the presence of dispersing agents or protective colloids, including the dispersing agents described in Specifications 219,349, 224,925, 242,393, 242,711, 269,960, 273,819, 273,820, 322,737, and 323,788, [all in Class 2 (iii), Dyes &c.].  Other additions may also be made; thus thickening agents may be added to produce pastes suitable for printing textiles.  Among the dyestuffs which may be ground in accordance with the invention, the insoluble or difficultly soluble azo, nitrodiarylamine and aminoanthraquinone dyes used in the colouration of materials containing cellulose acetate or other cellulose esters or ethers are specified.  When the dyestuff or pigment is to be afterwards employed in conjunction with an organic liquid of low surface tension, that liquid may conveniently be employed to prevent frothing, thus in grinding a pigment, e.g. titanium oxide, to be incorporated in a solution of cellulose acetate in acetone subsequently to be spun into artificial filaments, acetone may be employed as the liquid to prevent frothing.  In examples (1) titanium oxide is ground in a pebble mill with water and acetone, (2) 1-oxy-4-amino-anthraquinone is ground with water, methylated spirits and a dispersing or wetting agent, e.g. turkey red oil, and (3) 1 : 4-dimethylamino-anthraquinone is ground with common salt and a saturated salt solution with addition of methyl ated spirits.  The Provisional Specification describes the grinding of materials in general in liquid media, with the addition of any substances adapted to prevent frothing.ALSO:In grinding or milling insoluble or difficultly soluble dyestuffs or pigments in aqueous media, frothing is prevented by the addition of an organic liquid having a low-surface tension relative to that of water.  Suitable organic liquids are alcohols, e.g. methyl, ethyl and butyl alcohols, ethers, e.g. ethyl ethers, esters, e.g. ethyl acetate, ketones, e.g. acetone, and aromatic, hydroaromatic or aliphatic hydrocarbons, e.g. benzene or paraffin oil.  The grinding may be carried out in the presence of additional abrasive materials, which may be water-soluble to facilitate their removal from the finely divided material. Examples of such abrasives are boric acid and sodium chloride; thus an insoluble dyestuff may be ground with sodium chloride in the presence of a saturated solution of sodium chloride to which methylated spirits has been added to prevent frothing.  The grinding may also be effected in the presence of dispersing agents or protective colloids, including the dispersing agents described in Specifications 219,349, 224,925, 242,393, 242,711, 269,960, 273,819, 273,820, 322,737, and 323,788, [all in Class 2 (iii), Dyes &c.].  Other additions may also be made; thus thickening agents may be added to produce pastes suitable for printing textiles.  Among the dyestuffs which may be ground in accordance with the invention, the insoluble or difficultly soluble azo, nitrodiarylamine and aminoanthraquinone dyes used in the colouration of materials containing cellulose acetate or other cellulose esters or ethers are specified.  When the dyestuff or pigment is to be afterwards employed in conjunction with an organic liquid of low surface tension, that liquid may conveniently be employed to prevent frothing, thus in grinding a pigment, e.g. titanium oxide, to be incorporated in a solution of cellulose acetate in acetone subsequently to be spun into artificial filaments, acetone may be employed as the liquid to prevent frothing.  In examples (1) titanium oxide is ground in a pebble mill with water and acetone, (2) 1-oxy-4-aminoanthraquinone is ground with water, methylated spirits and a dispersing or wetting agent, e.g. turkey red oil, and (3) 1 : 4-dimethylaminoanthraquinone is ground with common salt and a saturated salt solution with addition of methylated spirits.  The Provisional Specification describes the grinding of materials in general in liquid media, with the addition of any substances adapted to prevent frothing.ALSO:In grinding or milling insoluble or difficultly soluble dyestuffs or pigments in aqueous media, frothing is prevented by the addition of an organic liquid having a low surface tension relative to that of water.  Suitable organic liquids are alcohols, e.g. methyl, ethyl, and butyl alcohols, ethers, e.g. ethyl ethers, esters, e.g. ethyl acetate, ketones, e.g. acetone, and aromatic, hydroaromatic or aliphatic hydrocarbons, e.g. benzene or paraffin oil.  The grinding may be carried out in the presence of additional abrasive materials, which may be water-soluble to facilitate their removal from the finely divided material. Examples of such abrasives are boric acid and sodium chloride; thus an insoluble dyestuff may be ground with sodium chloride in the presence of a saturated solution of sodium chloride to which methylated spirits has been added to prevent frothing.  The grinding may also be effected in the presence of dispersing agents or protective colloids, including the dispersing agents described in Specifications 219,349, 224,925, 242,393, 242,711, 269,960, 273,819, 273,820, 322,737, and 323,788, [all in Class 2 (iii), Dyes &c.].  Other additions may also be made; thus thickening agents may be added to produce pastes suitable for printing textiles.  Among the dyestuffs which may be ground in accordance with the invention, the insoluble or difficultly soluble azo, nitrodiarylamine and aminoanthraquinone dyes used in the colouration of materials containing cellulose acetate or other cellulose esters or ethers are specified.  When the dyestuff or pigment is to be afterwards employed in conjunction with an organic liquid of low surface tension, that liquid may conveniently be employed to prevent frothing, thus in grinding a pigment, e.g. titanium oxide, to be incorporated in a solution of cellulose acetate in acetone subsequently to be spun into artificial filaments, acetone may be employed as the liquid to prevent frothing.  In examples, (1) titanium oxide is ground in a pebble mill with water and acetone, (2) 1-oxy-4-aminoanthraquinone is ground with water, methylated spirits and a dispersing or wetting agent, e.g. turkey red oil, and (3) 1 : 4-dimethylaminoanthraquinone is ground with common salt and a saturated salt solution with addition of methylated spirits.  The Provisional Specification describes the grinding of materials in general in liquid media, with the addition of any substances adapted to prevent frothing.