Process for level exhaust of cellulose fibers with reactive dyes: addition of fixing alkali according to a parabolic time function

Claim 1

In a process for the level dyeing of textile material made from cellulose fibers or mixtures thereof with synthetic fiber types in an aqueous medium by the exhaust technique with reactive dyes which are fixable onto said cellulosic material under alkaline conditions, which process comprises adding an alkaline fixing agent at the fixing temperature and in a substantially continuous or approximately continuous manner, to the exhaust liquor containing the fibrous material to be dyed and at least one such reactive dye and all other ingredients, but containing no alkaline fixing agent, the improvement consisting of (a) adding, at the start of the dyeing process, in one portion 1/400 to 1/15 of the total amount of said alkaline fixing agent required to fix said reactive dyes on said cellulose fibers, (b) then adding continuously or approximately continuously, in the course of at most 20 minutes and in the manner of a parabolic function decreasing towards a value of nearly or equal zero, in a second addition step alkaline fixing agent in an amount of 1/630 to 1/5 of the total amount of said alkaline fixing agent, and (c) finally adding continuously or approximately continuously, in the manner of an increasing parabolic function, the residual alkaline fixing agent.