Disperse dyeing of textile fibers

Abstract

A process for dyeing textile fibers employs a colorant medium comprising a disperse dye and an aqueous dispersion of a copolymer selected from vinyl ester-based copolymers, alkyl acrylate copolymers, alkyl methacrylate copolymers and mixtures thereof. The textile fibers are passed through at least one dye bath containing the colorant medium to deposit the colorant medium at least on the surface of the fibers. The fibers with the colorant medium deposited thereon are then passed between padding rollers to distribute the colorant medium through the fibers, whereafter the fibers are heated to cure the copolymer and bond the disperse dye to the fibers.

1 . A process for dyeing textile fibers, the process comprising;
 (a) providing at least one dye bath comprising a colorant medium comprising a disperse dye and an aqueous dispersion of a copolymer selected from vinyl ester-based copolymers, alkyl acrylate copolymers, alkyl methacrylate copolymers and mixtures thereof;   (b) passing the textile fibers through the at least one dye bath to deposit the colorant medium at least on the surface of the fibers;   (c) passing the fibers with the colorant medium deposited thereon between padding rollers to distribute the colorant medium through the fibers; and then   (d) heating the fibers to cure the copolymer and bond the disperse dye to the fibers.   
     
     
         2 . The process of  claim 1 , wherein the textile fibers comprise natural fibers, preferably cellulosic fibers, more preferably cotton fibers, optionally together with synthetic fibers. 
     
     
         3 . The process of  claim 1 , wherein the copolymer comprises vinyl acetate and ethylene. 
     
     
         4 . The process of  claim 1 , wherein the copolymer comprises from 60 wt % to 95 wt % of vinyl acetate and from 5 wt % to 40 wt % of ethylene, based on total weight of monomers therein. 
     
     
         5 . The process of  claim 1  any preceding claim, wherein the copolymer comprises an alkyl acrylate and/or an alkyl methacrylate containing 1 to 12, preferably 1 to 10, carbon atoms in the alkyl group. 
     
     
         6 . The process of  claim 5 , wherein the copolymer further comprises acrylonitrile. 
     
     
         7 . The process of  claim 1  any preceding claim, wherein the copolymer comprises less than 25 wt % polyester. 
     
     
         8 . The process of  claim 1  any preceding claim, wherein the colorant medium comprises from 0.01 wt % to 15 wt % of the disperse dye. 
     
     
         9 . The process of  claim 1 , wherein the colorant medium has a solids content from about 2 wt % to about 10 wt %. 
     
     
         10 . The process of  claim 1 , wherein the colorant medium has a pH in the range from 2 to 8. 
     
     
         11 . The process of any  claim 1 , wherein the temperature of the colorant medium during step (b) is from 10° C. to 50° C. 
     
     
         12 . The process of any  claim 1 , wherein the textile fibers are passed through the dye bath at a rate of from 1 m/min to 70 m/min. 
     
     
         13 . The process of  claim 1 , wherein the padding rollers apply a pressure from 50 to 250 kPa to the textile fibers during step (c). 
     
     
         14 . The process of  claim 1 , wherein the heating (d) is conducted at a temperature from 100° C. to 200° C. for a period (dwell time) of from 0.2 to 4 minutes. 
     
     
         15 . The process of  claim 1 , wherein heating (d) produces a dyed textile fiber product comprising from 0.1 to 10 wt % of the copolymer on a dry basis based on the combined weight of the copolymer and textile fibers. 
     
     
         16 . The process of  claim 1 , wherein the fibers are continuously passed from step (b) to step (d).