Oil based ink composition for inkjet printer

Abstract

An oil based ink composition for inkjet printer comprising colored resin particles obtained by dispersion polymerization of a monofunctional polymerizable monomer (A) and a macromonomer (M) copolymerizable with the monomer (A) with coloring component fine particles comprising a surface-treated coloring agent, which are dispersed in a non-aqueous solvent having a dielectric constant of from 1.5 to 20 and a surface tension of from 15 to 60 mN/m at 25° C., as seed particles, in the presence of a dispersion stabilizer (P) soluble in the non-aqueous solvent and a polymerization initiator.

1 . A process of producing colored resin particles comprising performing dispersion polymerization of a dispersion comprising a monofunctional polymerizable monomer (A), a macromonomer (M) copolymerizable with the monomer (A), coloring component fine particles comprising a surface-treated coloring agent, which are dispersed in a non-aqueous solvent having a dielectric constant of from 1.5 to 20 and a surface tension of from 15 to 60 mN/m at 25° C., as seed particles, and a dispersion stabilizer (P) soluble in the non-aqueous solvent in the presence of a polymerization initiator.  
     
     
         2 . The process of producing colored resin particles as claimed in  claim 1 , wherein the macromonomer (M) is a macromonomer having a weight average molecular weight of from 1×10 3  to 4×10 4  in which a polymerizable double bond group represented by formula (I) shown below is connected to a terminal of the main chain of a polymer comprising a repeating unit represented by formula (II) shown below:  
       
         
           
           
               
               
           
         
       
       wherein V represents —COO—, —OCO—, —(CH 2 ) m —OCO—, —(CH 2 ) m —COO—, —O—, —CONHCOO—, —CONHCO—, —SO 2 —, —CO—, —CON(Z 1 )—, —SO 2 N(Z 1 )— or a phenylene group; Z 1  represents a hydrogen atom or a hydrocarbon group; m represents an integer of from 1 to 3; a 1  and a 2 , which may be the same or different, each represent a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, —COO—Z 2  or —COO—Z 2  linked through a hydrocarbon group; and Z 2  represents a hydrogen atom or a hydrocarbon group:  
       
         
           
           
               
               
           
         
       
       wherein X 0  represents a connecting group selected from —COO—, —OCO—, —(CH 2 ) n —OCO—, —(CH 2 ) n —COO—, —O—, —CONHCOO—, —CONHCO—, —SO 2 —, —CO—, —CON(Z 3 )— and —SO 2 N(Z 3 )—; Z 3  represents a hydrogen atom or a hydrocarbon group; n represents an integer of from 1 to 3; b 1  and b 2 , which may be the same or different, each have the same meanings as defined for a 1  and a 2  of formula (I); and Q 0  represents an aliphatic group having from 1 to 22 carbon atoms.  
     
     
         3 . The process of producing colored resin particles as claimed in  claim 1 , wherein the surface-treated coloring agent is an organic or inorganic pigment coated with a polymer.  
     
     
         4 . The process of producing colored resin particles as claimed in  claim 1 , wherein the coloring component fine particles are those dispersed with a pigment dispersant in the non-aqueous solvent and having an average particle diameter of from 0.01 to 1.0 μm.