Inkjet inks containing crosslinked polyurethanes

Abstract

Inkjet inks are described that have, as a principal component, a crosslinked polyurethane dispersoid binder additive. These inks can be used for printing on different media, and are particularly suitable for printing on textiles.

1 . An inkjet ink composition comprising an aqueous vehicle, a colorant and a crosslinked polyurethane dispersoid, wherein the colorant is soluble or dispersible in the aqueous vehicle, and wherein the weight ratio of crosslinked polyurethane to colorant is at least about 1.0.  
     
     
         2 . The inkjet ink composition of  claim 1 , wherein the ink comprises from about 0.1 to about 30% by weight of the colorant, based on the total weight of the ink.  
     
     
         3 . The inkjet ink composition of  claim 1 , wherein the ink comprises more than about 1% to about 30% by weight (solids basis) of the crosslinked polyurethane dispersoid, based on the total weight of the ink.  
     
     
         4 . The inkjet ink composition of  claim 1 , wherein the amount of crosslinking in the crosslinked polyurethane is greater than about 1% (THF insolubles test).  
     
     
         5 . The inkjet ink composition of  claim 1 , wherein the amount of crosslinking in the crosslinked polyurethane is less than about 50% (THF insolubles test).  
     
     
         6 . The inkjet ink composition of  claim 1 , wherein the ink comprises from about 0.1 to about 30% by weight of the colorant, and more than about 1% to about 30% by weight (solids basis) of the crosslinked polyurethane dispersoid, based on the total weight of the ink; and the amount of crosslinking in the crosslinked polyurethane is greater than about 1% and less than about 50% (THF insolubles test).  
     
     
         7 . The inkjet ink composition of  claim 1 , having a surface tension in the range of about 20 dyne/cm to about 70 dyne/cm, and a viscosity is in the range of about 1 cP to about 30 cP at 25° C.  
     
     
         8 . The inkjet ink composition of  claim 1 , wherein the crosslinked polyurethane has incorporated therein hydrophilic functionality to the extent required to maintain a stable dispersion of the polymer in the aqueous vehicle.  
     
     
         9 . The inkjet ink composition of  claim 1 , wherein the colorant comprises a pigment.  
     
     
         10 . An inkjet ink set comprising at least three differently colored inkjet inks, wherein at least one of the inks is an inkjet ink composition comprising an aqueous vehicle, a colorant and a crosslinked polyurethane dispersoid, wherein the colorant is soluble or dispersible in the aqueous vehicle, and wherein the weight ratio of crosslinked polyurethane to colorant is at least about 1.0.  
     
     
         11 . The inkjet ink set of  claim 10 , wherein the inkjet ink composition comprises from about 0.1 to about 30% by weight of the colorant, and more than about 1% to about 30% by weight (solids basis) of the crosslinked polyurethane dispersoid, based on the total weight of the ink; and the amount of crosslinking in the crosslinked polyurethane is greater than about 1% and less than about 50% (THF insolubles test).  
     
     
         12 . The inkjet ink set of  claim 11 , wherein the inkjet ink composition has a surface tension in the range of about 20 dyne/cm to about 70 dyne/cm, and a viscosity is in the range of about 1 cP to about 30 cP at 25° C.  
     
     
         13 . The inkjet ink set of  claim 10 , wherein the crosslinked polyurethane has incorporated therein hydrophilic functionality to the extent required to maintain a stable dispersion of the polymer in the aqueous vehicle.  
     
     
         14 . The inkjet ink set of  claim 10 , wherein the colorant comprises a pigment.  
     
     
         15 . The inkjet ink set of  claim 10 , wherein ink set comprises: 
 (a) a first colored ink comprising a first aqueous vehicle, a first colorant and a first crosslinked polyurethane dispersoid, wherein the first colorant is soluble or dispersible in the first aqueous vehicle, and wherein the weight ratio of the first polyurethane dispersoid to first colorant is at least about 1.0;    (b) a second colored ink comprising a second aqueous vehicle, a second colorant and a second crosslinked polyurethane dispersoid, wherein the second colorant is soluble or dispersible in the second aqueous vehicle, and wherein the weight ratio of the second polyurethane dispersoid to second colorant is at least about 1.0; and    (c) a third colored ink comprising a third aqueous vehicle, a third colorant and a third crosslinked polyurethane dispersoid, wherein the third colorant is soluble or dispersible in the third aqueous vehicle, and wherein the weight ratio of the third polyurethane dispersoid to third colorant is at least about 1.0.    
     
     
         16 . The inkjet ink set of  claim 15 , wherein the first colored ink is a cyan ink, the second colored ink is a magenta ink and the third colored ink is a yellow ink.  
     
     
         17 . The inkjet ink set of  claim 15 , further comprising (d) a fourth colored ink comprising a fourth aqueous vehicle, a fourth colorant and a fourth crosslinked polyurethane dispersoid, wherein the fourth colorant is soluble or dispersible in the fourth aqueous vehicle, and wherein the weight ratio of the fourth polyurethane dispersoid to fourth colorant is at least about 1.0.  
     
     
         18 . The inkjet ink set of  claim 17 , wherein the fourth colored ink is a black ink.  
     
     
         19 . A method for inkjet printing onto a substrate, comprising the steps of: 
 (a) providing an inkjet printer that is responsive to digital data signals;    (b) loading the printer with a substrate to be printed;    (c) loading the printer with an inkjet ink composition comprising an aqueous vehicle, a colorant and a crosslinked polyurethane dispersoid, wherein the colorant is soluble or dispersible in the aqueous vehicle, and wherein the weight ratio of crosslinked polyurethane to colorant is at least about 1.0.; and    (d) printing onto the substrate using the ink in response to the digital data signals.    
     
     
         20 . The method of  claim 19 , wherein the printer is loaded with an inkjet ink set comprising at least three differently colored inkjet inks, wherein at least one of the inks is an inkjet ink composition comprising an aqueous vehicle, a colorant and a crosslinked polyurethane dispersoid, wherein the colorant is soluble or dispersible in the aqueous vehicle, and wherein the weight ratio of crosslinked polyurethane to colorant is at least about 1.0; and wherein the printing onto the substrate uses the inkjet ink set.  
     
     
         21 . The method of  claim 19 , wherein the substrate is a textile.  
     
     
         22 . The method of  claim 21 , wherein the printed substrate is post treated with a combination of heat and pressure.  
     
     
         23 . The method of  claim 21 , wherein the printed textile has a wash fastness of at least 2.0 and a stain rating of at least 3.3 (as measured in accordance with AATCC Test Method 61-1996 as the 2A test).  
     
     
         24 . An inkjet printed textile inkjet printed with a pigmented inkjet ink, said printed textile having a wash fastness of at least 2.0 and a stain rating of at least 3.0 (as measured in accordance with AATCC Test Method 61-1996 as the 2A test).