Water-based inks for ink-jet printing

Abstract

The present invention relates to a water-based ink for ink-jet printing which not only satisfies a high optical density but also exhibits excellent high lighter-fastness and gloss; and a water dispersion used for the water-based ink. There are provided a water dispersion for ink-jet printing containing (A) a self-dispersible pigment, (B) self-emulsifiable polymer particles containing a constitutional unit derived from a salt-forming group-containing monomer, and (C) emulsion polymer particles; and a water-based ink containing the water dispersion.

1 . A water dispersion for ink-jet printing comprising (A) a self-dispersible pigment, (B) self-emulsifiable polymer particles containing a constitutional unit derived from a monomer containing a salt-forming group, and (C) emulsion polymer particles. 
   
   
       2 . The water dispersion for ink-jet printing according to  claim 1 , wherein the self-emulsifiable polymer particles (B) are polymer particles obtained by neutralizing a water-insoluble polymer containing a constitutional unit derived from a monomer containing a salt-forming group (a), and a constitutional unit derived from a macromer (b) and/or a constitutional unit derived from a hydrophobic monomer (c). 
   
   
       3 . The water dispersion for ink-jet printing according to  claim 1 , wherein the emulsion polymer particles (C) are polymer particles produced by polymerizing an ethylenically unsaturated monomer in the presence of a reactive surfactant. 
   
   
       4 . The water dispersion for ink-jet printing according to  claim 1 , wherein the emulsion polymer particles (C) are (meth)acrylic-styrene-based polymer particles. 
   
   
       5 . The water dispersion for ink-jet printing according to  claim 1 , wherein the self-dispersible pigment (A) is self-dispersible carbon black. 
   
   
       6 . The water dispersion for inkjet printing according to  claim 1 , wherein a weight ratio of the self-emulsifiable polymer particles (B) to the emulsion polymer particles (C) in the water dispersion is from 1/10 to 10/1. 
   
   
       7 . The water dispersion for ink-jet printing according to  claim 1 , wherein a weight ratio of a sum of the self-emulsifiable polymer particles (B) and the emulsion polymer particles (C) to the self-dispersible pigment (A) in the water dispersion is from 1/10 to 2/1. 
   
   
       8 . A water-based ink for ink-jet printing comprising the water dispersion as defined  claim 1 . 
   
   
       9 . A method of ink-jet printing using the water-based ink as defined in  claim 8 .