Digital printing ink

Abstract

A digital printing ink including chitosan, a surfactant, and a balance of a solvent is provided. The chitosan has a weight-average molecular weight of 200,000 to 300,000. The surfactant includes a polyglycol, an ethylene oxide, or a combination thereof. The digital printing ink has a viscosity of 2 cps to 12 cps, a surface tension of 28 dyne/cm to 40 dyne/cm, and a pH value of 6 to 8. A content of the chitosan is 5 wt. % to 10 wt. %, and a content of the surfactant is 2 wt. % to 5 wt. %, based on the total weight of the digital printing ink.

What is claimed is: 
     
         1 . A digital printing ink for forming an inkjet pattern on a fabric, the digital printing ink comprising:
 chitosan having a weight-average molecular weight of 200,000 to 300,000;   a surfactant comprising polyglycol, ethylene oxide, or a combination thereof; and   a balance of a solvent,   wherein the digital printing ink has a viscosity of 2 cps to 12 cps, a surface tension of 28 dyne/cm to 40 dyne/cm, and a pH value of 6 to 8, and   wherein a content of the chitosan is 5 wt. % to 10 wt. %, and a content of the surfactant is 2 wt. % to 5 wt. %, based on the total weight of the digital printing ink.   
     
     
         2 . The digital printing ink of  claim 1 , further comprising a pH regulator, wherein the pH regulator comprises triethanolamine, a phosphate solution, or a combination thereof, and a content of the pH regulator is 0.1 wt. % to 0.4 wt. %, based on the total weight of the digital printing ink. 
     
     
         3 . The digital printing ink of  claim 1 , further comprising a coupling agent, wherein the coupling agent comprises a polymer having an ethylene oxide side chain, and a content of the coupling agent is 0.01 wt. % to 0.06 wt. %, based on the total weight of the digital printing ink. 
     
     
         4 . The digital printing ink of  claim 1 , further comprising a humectant, wherein the humectant comprises glycerin, and a content of the humectant is 4 wt. % to 6 wt. %, based on the total weight of the digital printing ink. 
     
     
         5 . The digital printing ink of  claim 1 , further comprising a cosolvent, wherein the cosolvent comprises propylene glycol methyl ether, and a content of the cosolvent is 4 wt. % to 6 wt. %, based on the total weight of the digital printing ink. 
     
     
         6 . The digital printing ink of  claim 1 , wherein the solvent comprises deionized water. 
     
     
         7 . The digital printing ink of  claim 1 , wherein the polyglycol has a weight-average molecular weight of 400 to 600.