Increasing receptivity for acid dyes

Abstract

Dye receptivity of fibers used in the dyeing and printing of cationic dyeable nylon as used as carpet fibers or similar polymers difficult to dye with anionic dyes are improved by a coating rendering these fibers more receptive to anionic dyes.

1 . A process for increasing the receptivity of cationic dyeable nylon fiber or other difficult to dye polymer fiber to acid dye comprising: 
 (1) applying to the fiber a cationic polymer coating that is receptive to acid dye and provides anionic dye sites for subsequent coloration, and thereafter    (2) applying an acid dye or premetallized acid dye to the thus treated polymer and dyeing the fiber.    
   
   
       2 . The process of  claim 1  wherein the fiber is a cationic dyeable nylon.  
   
   
       3 . The process of  claim 1  wherein the fiber is polyvinyl chloride, polypropylene, polyester or combinations of two or more of these.  
   
   
       4 . The process of  claim 1  in which the receptivity-improving polymer is a cationic styrene-acrylic copolymer.  
   
   
       5 . The process of  claim 1  in which the receptivity-improving polymer is a cationic acrylic copolymer.  
   
   
       6 . The process of  claim 1  in which the receptivity-improving polymer is a styrene maleic anhydride imide resin.  
   
   
       7 . The process of  claim 1  in which the receptivity-improving polymer is a maleic anhydride adhesive polymer.  
   
   
       8 . The process of  claim 1  in which the receptivity-improving polymer is a poly-diallyl dimethyl ammonium chloride.  
   
   
       9 . The process according to  claim 1  wherein in step (2) the fibers are dyed with an acid dye or a premetallized acid dye at a pH of from about 2.0 to about 6.5 and thereby fixing dye to the fibers.  
   
   
       10 . The process according to  claim 1  wherein in step (2) the fibers are dyed with an acid dye or a premetallized acid dye at a pH of from 2.0 to 6.5 to impart a pre-requisite depth of shade to the nylon fibers, and an additional step of 
 (3) heating the dye-laden fibers to fix the dye into the fibers.    
   
   
       11 . The process of  claim 1 , in which the cationic dyeable nylon fibers contain SO 3 H and/or COOH groups receptive to cationic or basic dyes.  
   
   
       12 . The process of  claim 1 , in which, subsequent to dye fixation, a fluorocarbon soil repellant is applied to the fibers.  
   
   
       13 . A method of increasing the receptivity of cationic dyeable nylon fibers to acid dye comprising 
 (1) applying to the nylon fibers a cationic acrylic polymer or cationic styrene-acrylic polymer receptive to acid dye, and thereafter    (2) dyeing the treated fibers of step (1) with an acid dye.    
   
   
       14 . The process of  claim 13  in which the fibers are in the form of a yarn.  
   
   
       15 . Nylon carpet having improved stain resistance composed of fibers comprised of a cationic dyeable nylon treated with a cationic polymer acid dye receptivity agent then dyed at a pH of from about 2.0 to 6.5 with an acid or premetallized acid dye.  
   
   
       16 . A process for increasing the receptivity of cationic dyeable nylon fiber or other difficult to dye polymer fiber to acid dye comprising: 
 (1) applying to the fiber a cationic polymer coating that is receptive to acid dye, and provides anionic dye sites for subsequent coloration, and thereafter    (2) applying an acid dye or premetallized acid dye to the thus treated polymer and dyeing the fiber,    wherein the fibers treated in step (1) have an increase in anionic dye dyeability, when measured by spectrophotometry, up to 100% or greater as compared to fibers not subjected to treatment prior to step (2).    
   
   
       17 . The process of  claim 16  in which the increase in anionic dye dyeability, when measured by spectrophotometry, is at least 100% as compared to fibers not subjected to treatment prior to step (2).