Printing process

DETAILED DESCRIPTION We claim: 1.
A process for printing a fiber assemblage comprising acrylic fibers dyeable with cationic dyes and blend fibers dyeable with anionic dyes with a printing paste containing a cationic dye and an anionic dye which process comprises preparing said printing paste so as to contain lignin sulfonic acid or a soluble salt thereof in an amount by weight greater than the total amounts by weight of cationic and anionic dyes present, printing said fiber assemblage with the thus-prepared printing past and thereafter steaming the thus-treated fiber assemblage to fix the dyes thereon.
2.
The process of claim 1 wherein the amount of lignin sulfonic acid or soluble salt thereof is from 2 to 8 weight percent based on the total weight of printing paste.
3.
The process of claim 1 wherein steaming is carried out at a temperature in the range of 95.
degree.
C.
to 120.
degree.
C.
for at least about 5 minutes.
4.
The process of claim 1 wherein the paste-forming material is carboxymethyl cellulose.
5.
The process of claim 1 wherein a printing auxiliary is also present in said printing paste.
6.
The process of claim 1 wherein the anionic dye is a reactive dye and a polyamine complex salt is incorporated in the printing paste.




Description:
This invention relates to an improved process for printing a fiber blend with dyes of opposing ionic charges.
More particularly, the invention relates to a process for printing a fiber assemblage containing acrylic fibers dyeable with basic dyes and blend fibers dyeable with acid dyes, the printing paste containing a mixture of cationic and anionic dyes which are stabilized against interaction and precipitation by addition of a specific amount of lignin sulfonic acid or a salt thereof to the printing paste.
When a fiber assemblage such as blend-spun, blend-woven, or blend-knit articles consisting of commercially available cationic-dyeable acrylic fibers and anionic-dyeable fibers such as cotton, wool, rayon, nylon, and the like are dyed using conventional immersion dyeing techniques, it has been customary procedure to dye the acrylic fiber with a cationic dye and the blend fiber with an anionic dye in conformity with the dyeing characteristics of the respective fibers employed