Disazo dyes and their use in dyeing

摘要

The invention comprises disazo dyes of formula wherein a, c and n are each 0, 1, 2 or 3 and b, d and m are each 0, 1 or 2, if m + n exceeds 0 then a + b must be at least 1, if a + b + m + n is 0 then the total number of carbon atoms in (R3)c and (R4)d msut be at least 3, wherein c and d have positive values only when a + b + m + n = 0 and wherein each X represents an acyl group derived from a C1- 6 carboxylic acid, an N-alkyl- or N,N-dialkyl-sulphonamido, dialkylamino, alkoxy, carboalkoxy, carboxy, nitro, benzoyl, substituted benzoyl, hydroxy, trifluoromethyl, cyano, benzoylamino, b -cyanoethoxy, methylsulphonyl, thiocyano, substituted benzoylamino, mono- or di-b -hydroxyethylamino or di-b -cyanoethylamino group or a halogen atom, Y is a cycloalkyl, alkoxy, b -hydroxy-or -cyanoethoxy or trifluoromethyl group or a halogen atom, Z is a hydrogen atom or a methyl group and R1, R2, R3 and R4 ar C1- 20 alkyl groups. The dyes are prepared by coupling appropriately substituted diazotized aminoazobenzenes with salicylic acid or 3-methylsalicylic acid. Metal complexes of the dyes may be prepared by reaction with a metallizing agent, e.g. a zinc or aluminium compound. The dyes are preferably used to colour synthetic materials, e.g. polyolefins, polyamides, polyesters, polyacetals and polyacrylonitrile containing zinc or aluminium compounds. The dyes may also be used to colour wool, silk and animalized cotton. Yellow, red and brown shades are obtained.