| 摘要 |
The invention comprises a composition comprising at least one non-metallised and non-metallisable acid dye that is capable of dyeing nylon fibres from a substantially neutral to weakly acid solution, and at least a molecular equivalent of a premetallised azo dye-chromium-complex containing at least one sulphonic group, wherein the dye and Cr are present in a molar ratio of 1:1, the premetallised dye is free of dye-metal complexes in which the dye metal ratio is 2:1, and the metallised portion is free from unchromed dye and is soluble in neutral and weakly alkaline aqueous solutions, and wherein the premetallised dye is one in which the Cr is bound to an azo dye by reaction with groups positioned ortho, ortho/sv to the azo linkage one of these original groups being -OH and the other being -OH1 -NH2 or -COOH. Some 1:1 Cr complexes may have their water-solubility increased by further complexing with certain aliphatic carboxylic acids. The dye compositions can be applied to nylon simultaneously from a single bath or the individual components of the composition can be applied sequentially from the same bath or sequentially from different dyebaths. When the dyestuffs are applied sequentially from the same bath the dye composition is applied to nylon fibres from an aqueous solution, the fibres remaining in the solution until the acid dye component is completely exhausted and thereafter the fibres are dyed in the presence of acid at elevated temperatures with a sufficient quantity of the premetallised dye component. When the dyes are applied from different baths, the non-metallised dye component is first applied and thereafter the premetallised dye is applied. The preferred method involves applying the dye compositions from a neutral dye bath to dye on the acid dye component and then lowering the pH to dye on the premetallised dye component. Examples of the dyeing processes are given. |
