Ink Composition, Recording Method Using the Same, and Recorded Matter

Abstract

An ink composition comprises at least a coloring agent coated with a water-insoluble polymer and resin particles. The water-insoluble polymer is a polymer obtained by a solution polymerization process using at least a polymerizable unsaturated monomer and a polymerization initiator. The coloring agent coated with the water-insoluble polymer is a coloring material obtained by a phase inversion emulsification process in which, after the water-insoluble polymer is dissolved in an organic solvent, at least the coloring agent and water are added thereto, followed by mixing. The organic solvent is removed to perform dispersion in an aqueous system. The resin particles are a polymer obtained by an emulsion polymerization process using at least a crosslinking agent. The average particle size of the resin particles is from 20 to 80 nm.

1 . An ink composition comprising at least a coloring agent coated with a water-insoluble polymer and resin particles, wherein the water-insoluble polymer is a polymer obtained by a solution polymerization process using at least a polymerizable unsaturated monomer and a polymerization initiator, wherein the coloring agent coated with the water-insoluble polymer is a coloring material obtained by a phase inversion emulsification process in which after the water-insoluble polymer is dissolved in an organic solvent, at least the coloring agent and water are added thereto, followed by mixing, and the organic solvent is removed to perform dispersion in an aqueous system, and
 wherein the resin particles are a polymer obtained by an emulsion polymerization process using at least a crosslinking agent, and   wherein the average particle size of the resin particles is from 20 to 80 nm.   
     
     
         2 . The ink composition according to  claim 1 , wherein the coloring agent is a coloring agent insoluble in water. 
     
     
         3 . The ink composition according to  claim 1 , wherein the water-insoluble polymer is a branched polymer. 
     
     
         4 . The ink composition according to  claim 1 , wherein the resin particles comprise a polymer which does not form a film at a temperature of 40° C. or less. 
     
     
         5 . The ink composition according to  claim 1 , wherein the coloring agent is a pigment, the ink composition further contains water and a water-soluble organic compound, and the average particle size of the resin particles in the ink composition ranges from 50 to 150 nm. 
     
     
         6 . The ink composition according to  claim 5 , wherein the water-soluble organic compound comprises at least a polyhydric alcohol, a solid wetting agent and a butyl ether of a glycol. 
     
     
         7 . The ink composition according to  claim 6 , wherein the polyhydric alcohol comprises two or more members selected from glycerol, diethylene glycol, triethylene glycol, 1,5-pentanediol and 1,2-hexanediol, the solid wetting agent is trimethylolethane, trimethylolpropane or urea, and the butyl glycol is diethylene glycol monobutyl ether or triethylene glycol monobutyl ether. 
     
     
         8 . The ink composition according to  claim 1 , wherein it is used in an ink jet recording system. 
     
     
         9 . A recording method comprising a step of rendering the ink composition according to  claim 1  to attach onto a recording medium to perform printing. 
     
     
         10 . The recording method according to  claim 9 , wherein the method further comprises a step of ejecting droplets of the ink, and the droplets are rendered to attach onto the recording medium to perform printing. 
     
     
         11 . Recorded matter recorded by the recording method according to  claim 9 .