Aqueous coloring agent dispersion for inkjet, ink composition, inkjet recording method, and colored body

Abstract

Provided are an aqueous coloring agent dispersion for inkjet which achieves high pigment concentration, exhibits favorable redispersion properties after drying, and does not exhibit changes in ink properties even when stored for a long time; and an ink composition using the aqueous coloring agent dispersion. This aqueous coloring agent dispersion contains a coloring agent (I), a liquid medium (II), and a polymer dispersion agent (III). The polymer dispersion agent (III) is an A-B block polymer obtained by copolymerizing via a living radical polymerization method, by using a mixture of an organic tellurium compound represented by formula (1) and an organic ditellurium compound represented by formula (2), or the like, as a polymerization initiator. Therein, the monomer for configuring the A block is at least one type of monomer represented by formula (3), and the monomer for configuring the B block is benzyl methacrylate and/or benzyl acrylate.

1 . An aqueous coloring agent dispersion for inkjet comprising at least a coloring agent (I), a liquid medium (II), and a polymer dispersion agent (III),
 wherein the polymer dispersion agent (III) is an A-B block polymer obtained by copolymerizing, via a living radical polymerization method, by using as a polymerization initiator any one of a mixture of an organic tellurium compound and an organic ditellurium compound, and a mixture of the organic tellurium compound, an azo-based polymerization initiator, and the organic ditellurium compound,   wherein the organic tellurium compound is represented by the following formula (1):   
       
         
           
           
               
               
           
         
         wherein, R 1  represents a C 1 -C 8  alkyl group, an aryl group, a substituted aryl group, or an aromatic heterocyclic group; R 2  and R 3  represent a hydrogen atom or a C 1 -C 8  alkyl group; and R 4  represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group, or a cyano group, and 
         the organic ditellurium compound is represented by the following formula (2):
   (R 1 Te) 2   (2)
 
 
         wherein, R 1  has the same meaning as that of R 1  in the above formula (1), 
         wherein A and B each mean polymers obtained by polymerizing different monomers, and 
         the monomer for configuring the A block is one or more kinds of the monomers represented by the following formula (3): 
       
       
         
           
           
               
               
           
         
         wherein, R 5  represents a hydrogen atom or an alkyl group having 4 carbon atoms which may have a branch; and R 6  represents a hydrogen atom or a methyl group, and 
         the monomer for configuring the B block is benzyl methacrylate and/or benzyl acrylate. 
       
     
     
         2 . The aqueous coloring agent dispersion for inkjet according to  claim 1 , wherein an acid value of the polymer dispersion agent (III) is 90 to 200 mg KOH/g. 
     
     
         3 . The aqueous coloring agent dispersion for inkjet according to  claim 1 , wherein a mass average molecular weight of the polymer dispersion agent (III) is 10,000 to 60,000. 
     
     
         4 . The aqueous coloring agent dispersion for inkjet according to  claim 1 , wherein the monomer for configuring the A block is two kinds of monomer in which R 5  is a hydrogen atom and R 6  is a methyl group in the above formula (3) and a monomer in which R 5  is an n-butyl group and R 6  is a methyl group in the above formula (3). 
     
     
         5 . The aqueous coloring agent dispersion for inkjet according to  claim 1 , wherein the coloring agent (I) is a pigment or a disperse dye. 
     
     
         6 . A method for producing the aqueous coloring agent dispersion for inkjet according to  claim 1 , the method comprising a process of covering the surface of the coloring agent (I) with the polymer dispersion agent (III). 
     
     
         7 . An ink composition for inkjet recording comprising the aqueous coloring agent dispersion for inkjet according to  claim 1  or an aqueous coloring agent dispersion for inkjet obtained by a method comprising covering the surface of the coloring agent (I) with the polymer dispersion agent (III). 
     
     
         8 . An inkjet recording method comprising: utilizing the ink composition for inkjet recording according to  claim 7  as an ink; and discharging ink droplets of the ink according to a recording signal so that recording is performed on a record-receiving material. 
     
     
         9 . The inkjet recording method according to  claim 8 , wherein the record-receiving material is a communication sheet. 
     
     
         10 . The inkjet recording method according to  claim 9 , wherein the communication sheet is a sheet having an ink-receiving layer containing a porous white inorganic material. 
     
     
         11 . The inkjet recording method according to  claim 9 , wherein the communication sheet is a medium for recording which is subjected to a surface modification treatment selected from a corona discharge treatment, a plasma treatment, and a flame treatment. 
     
     
         12 . A colored body colored with the ink composition for inkjet recording according to  claim 7 . 
     
     
         13 . An inkjet printer loaded with a container containing the ink composition for inkjet recording according to  claim 7 .