Various reactive dyes have been known. They have been widely used for dyeing cellulosic fibers. The reactive dyes have reactive groups such as monochloro-triazinyl, monofluoro-triazinyl, fluoro-chloro-pyrimidinyl, dichloro-quinoxazinyl, vinylsulfonyl, sulfato-ethylsulfonyl and the like. For dyeing, the reactive dye is used in the presence of an acid binder such as sodium carbonate, sodium hydroxide, sodium metasilicate and the like in a dyeing bath having a pH of 10 or higher and a temperature of 100° C. or less. The acid binder is often added stepwise during a dyeing step in order to avoid problems such as unlevel dyeing, lowering in color yield due to hydrolysis and the like.
On the other hand, cellulose-containing blended fibers, especially blended cotton/polyester fibers are commercially employed in large quantities since they give comfortable clothes.
A disperse dye used for dyeing polyester fibers is generally used in a dye bath having an acid to neutral pH and a temperature of about 100 to 140° C. in order to avoid its decomposition and alteration. These dyeing conditions of a disperse dye do not agree with those of a reactive dye. Therefore, when blended fibers are dyed, a two bath method wherein respective fibers are independently treated in respective dye bath and an one bath/two step method wherein both fibers are successively treated in one dye bath while sliding dying conditions for each fibers.
For purposes of reducing a dyeing time, saving energy, simplifying dyeing operations and the like, a reasonable dyeing method wherein there is no need for controlling a delicate and complicated addition of an agent during a dyeing step has been desired. And, in the dyeing of blended polyester/cotton fibers, an efficient one bath/one step dyeing method wherein both fibers are dyed simultaneously in one dye bath is desired. This one bath/one step dyeing method is sometime referred to as “one bath dyeing method”. A reactive dye used in this method should have a stability without causing a decomposition and a high dyeing property under conditions of dyeing polyester fibers with a disperse dye, that is, in a dye bath having an acidic to neutral pH and a temperature of 100 to 140° C.
Some reactive dyes having the above properties have been proposed. Yellow reactive dyes relating to the present invention can be exemplified in, for example, JP-A-60-086168 (1985), JP-A-01-308460 (1989) and the like. However, the dyes described in these patents have not always satisfactory properties. For example, the dyes do not show sufficient dyeing property over a relatively low temperature range around 100° C. and therefore a high color yield is not attained. Problems such as color breakup and unlevel dyeing upon dyeing using a mixed dye comprising a reactive dye and other dye are observed so that a formulation compatibility, a reproducibility and the like are not still satisfactory. Thus, the development of a yellow reactive dye which always shows a high dyeing property, has a good reproducibility and excellent fastnesses in various aspects such as a fastness to light, a fastness to chlorinated water, a fastness to washing and the like, and does not invite problems such as thermal discoloration, phototropy and the like is strongly desired.
In addition, in a mixed dye comprising a yellow reactive dye together with a red reactive dye and/or a blue reactive dye, reactive dyes having a reactive groups such as carboxypyridinio-triazinyl group, for example C.I. Reactive Yellow 162, 163, 178; C.I. Reactive Red 221; C.I. Reactive Blue 216, 217; and the like have been used.
When a mixed dye comprising the above known reactive dye is used for dyeing, however, many problems such as a poor dyeing reproducibility and an unlevel dyeing property caused by the difference in dyeing property of dyes to be mixed, a color transfer (migration) during a drying step caused by a poor washing of a non-fixed dye, and the like are found.
Thus, in a mixed dye comprising a yellow reactive dye together with a red reactive dye and/or a blue reactive dye, the development of a reactive dye composition which shows negligible change in hue with the change of dyeing conditions including an inorganic salt concentration, a bath ratio, a pH of a dye bath, a dyeing temperature, a dyeing period and the like over a wide temperature range from 90 to 140° C., excellent dyeing reproducibility and excellent washing property of a non-fixed dye and without causing problems such as a color transfer of a non-fixed dye during a drying step and the like is desired. Further, the development of a reactive dye composition having excellent formulation compatibility brought about by harmonizing a dyeing property of each dye component and the development of a method of dyeing cellulose fibers or cellulose-containing fibers are strongly desired.