Process and apparatus for production of yarn having longitudinally variable dye uptake

Abstract

Apparatuses and processes for producing yarn having longitudinally variable dye uptake and well as yarns having longitudinally variable dye uptake and articles prepared from these yarns are provided.

1 . A method for producing yarn having longitudinally variable dye uptake comprising:
 a) providing a yarn;   b) partially wetting the yarn to provide discontinuous wet and dry regions along the length of the yarn;   c) heating the discontinuously wetted yarn to impart longitudinally variable dye uptake to the yarn.   
     
     
         2 . The process of  claim 1  wherein the yarn is twisted. 
     
     
         3 . The process of  claim 2  where the twisted yarn is a textured twisted yarn. 
     
     
         4 . The process of  claim 3  wherein the textured twisted yarn is bulked. 
     
     
         5 . The process of any one of the preceding claims wherein the yarn comprises continuous filaments. 
     
     
         6 . The process of any one of  claims 1  through  4  wherein the yarn comprises staple. 
     
     
         7 . The process of any one of the preceding claims wherein the heating is performed by radiant, convective or conductive heat transfer. 
     
     
         8 . The process of  claim 7  wherein the radiant heating comprises irradiating with microwave or infrared energy. 
     
     
         9 . The process of  claim 7  wherein the heating comprises direct contact with steam. 
     
     
         10 . The process of  9  wherein the steam is superheated or saturated. 
     
     
         11 . The process of any one of the preceding claims wherein the yarn remains discontinuously wetted upon entering the heating step. 
     
     
         12 . The process of any one of the preceding claims wherein the yarn comprises a dyeable polymer. 
     
     
         13 . The process of  claim 12  wherein the dyeable polymer is selected from polyamides, polyesters, polyolefins and copolymers and blends thereof. 
     
     
         14 . The process of  claim 13  wherein the polyamide is selected from nylon, silk and wool. 
     
     
         15 . The process of  14  wherein the nylon is the product of a condensation reaction. 
     
     
         16 . The process of any one of the preceding claims wherein wetting step (b) is performed using a fluid dispensing system. 
     
     
         17 . The process of  claim 16  wherein the fluid dispensing system is selected from the group consisting of air-powered dispensers, dispense valve systems, automated dispensers, dispensing syringe barrels, dispensing pistons, dispensing cartridges, peristaltic pumps, mechanical pumps, manual pumps, syringes, volumetric dispensers, gravimetric dispensers, and squirt guns. 
     
     
         18 . The process of any one of the preceding claims wherein the yarn is wetted in step (b) for a period of about 0.5 to about 7 seconds. 
     
     
         19 . The process of any one of the preceding claims wherein wetting step (b) is performed under hot air at a temperature in the range from about 110° C. to about 150° C. 
     
     
         20 . The process of any one of the preceding claims wherein step (c) is achieved with saturated steam at a temperature in the range from about 120° C. to about 160° C. 
     
     
         21 . The process of any one of the preceding claims wherein step (c) is performed for a period of about 25 to about 60 seconds. 
     
     
         22 . An apparatus for producing yarn having longitudinally variable dye uptake, said apparatus comprising a fluid dispenser system for discontinuously wetting yarn and a guide for transferring the discontinuously wetted yarn to a heater. 
     
     
         23 . The apparatus of  claim 22  further comprising a heater to heat the discontinuously wetted yarn. 
     
     
         24 . The apparatus of  claim 22  wherein the fluid dispenser system is selected from the group consisting of air-powered dispensers, dispense valve systems, automated dispensers, dispensing syringe barrels, dispensing pistons, dispensing cartridges, peristaltic pumps, mechanical pumps, manual pumps, syringes, volumetric dispensers, gravimetric dispensers and squirt guns. 
     
     
         25 . Yarn of uniform composition and cross-sectional size having controlled variable dye uptake along its length. 
     
     
         26 . An article at least a portion of which is formed from yarn of  claim 25 . 
     
     
         27 . A carpet at least a portion of which is formed from yarn of  claim 25 .