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, polyvinyl chloride or polypropylene fiber, or combinations of two or more of these polymers difficult to acid dye, the process consisting of:
 (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 premetalized 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 or polypropylene, or combinations of two or more of these. 
     
     
         4 . The process of  claim 1  in which the cationic polymer is a cationic styrene-acrylic copolymer. 
     
     
         5 . The process of  claim 1  in which the cationic polymer is a cationic acrylic copolymer. 
     
     
         6 . The process according to  claim 1  wherein in step (2) the fibers are dyed with an acid dye or a premetalized acid dye at a pH of from about 2.0 to about 6.5 and thereby fixing dye to the fibers. 
     
     
         7 . The process according to  claim 1  wherein the fiber is cationic dyeable nylon and in step (2) the fibers are dyed with an acid dye or a premetalized 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.   
     
     
         8 . 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. 
     
     
         9 . A process of increasing the receptivity of cationic dyeable nylon fibers to acid dye, the process consisting of:
 (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.   
     
     
         10 . The process of  claim 9  in which the fibers are in the form of a yarn. 
     
     
         11 . 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 premetalized acid dye. 
     
     
         12 . A process for increasing the receptivity of cationic dyeable nylon, polyvinyl chloride or polypropylene fiber or combinations of two or more of these polymers difficult to acid dye, the process consisting of:
 (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 premetalized 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).   
     
     
         13 . The process of  claim 12  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). 
     
     
         14 . A process for increasing the receptivity of a cationic dyeable nylon that is not normally dyeable with acid dyes comprising:
 (1) applying to the cationic dyeable nylon 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 premetalized acid dye to the thus treated polymer and dyeing the fiber, wherein the acid dye or premetalized acid dye has a pH of from about 2.0 to 6.5.