METALLIFEROUS DISAZO DYES THEIR PRODUCTION AND USE

1299405 Metal complex disazo dyes SANDOZ Ltd 24 April 1970 [14 May 1969 2 June 1969] 19797/70 Heading C4P Metalliferous disazo dyes have the formula wherein Me represents a metal atom and the ring A and/or the ring B may be further substituted. The dyes are generally present in the form of their alkali metal salts or their ammonium salts, and preferably their sodium salts. The dyes are produced by coupling 1 mole of a tetrazotized 4,41 - diamino - 3,31 - dimethoxydiphenyl or 4,41 - diamino 3,31 - dihydroxydiphenyl with 1 mole of 2-hydroxynaphthalene 6,8-disulphonic acid and 1 mole of 2-hydroxynaphthalene-3,6-disulphonic acid and treating the resulting azo dyes with a metal donating agent. Preferred metals are nickel and copper. In use, the dyes may be made into dry preparations comprising 30-90% by weight of dye a 70-10% by weight of a standardizing agent, e.g. Glaubers salt. They may also be used in the form of liquid preparations comprising 5-30% by weight of dye, 5-30% by weight of an amine and 40-90% by weight of water. The dyes give reddish blue shades on paper and cellulose fibre materials.