Non-aqueous inkjet ink and ink set

Abstract

A non-aqueous inkjet ink includes a polyvinyl chloride resin synthesized by a suspension polymerization method or an emulsion polymerization method, an organic solvent that is a mixed solvent including diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, and diethylene glycol monoethyl ether in which the polyvinyl chloride resin is dissolved. This inkjet ink also includes a pigment, and a radical polymerization inhibitor. The radical polymerization inhibitor prevents the polyvinyl chloride resin from gelling in a short period and causing a discharge fault, clogging, etc. An ink set of inkjet inks includes a combination of the non-aqueous inkjet inks above having respective colors and including at least a cyan ink, a magenta ink, a yellow ink, and a black ink.

What is claimed is: 
     
         1 . A non-aqueous inkjet ink, comprising:
 a polyvinyl chloride resin synthesized by a suspension polymerization method or an emulsion polymerization method;   an organic solvent that is a mixed solvent comprising diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, and diethylene glycol monoethyl ether in which the polyvinyl chloride resin is dissolved;   a pigment; and   a radical polymerization inhibitor.   
     
     
         2 . The non-aqueous inkjet ink according to  claim 1 , wherein the radical polymerization inhibitor is selected from the group consisting of hydroquinones, catechols, hindered amines, phenols, phenothiazines, condensed aromatic ring quinones, and combinations thereof. 
     
     
         3 . The non-aqueous inkjet ink according to  claim 1 , wherein the polyvinyl chloride resin is a vinyl chloride-vinyl acetate copolymer, and wherein the vinyl chloride-vinyl acetate copolymer has a vinyl content that is no less than 1 mass % and no more than 36 mass %. 
     
     
         4 . The non-aqueous inkjet ink according to  claim 1 , wherein the non-aqueous inkjet ink further comprises a benzotriazole. 
     
     
         5 . The non-aqueous inkjet ink according to  claim 1 , wherein the pigment is a phthalocyanine pigment, and wherein the radical polymerization inhibitor is a hindered amine present in an amount based on total amount of the non-aqueous inkjet ink that is no less than 0.2 mass % and no more than 2 mass %. 
     
     
         6 . The non-aqueous inkjet ink according to  claim 1 , wherein the pigment is a quinacridone pigment, and wherein the radical polymerization inhibitor is a hindered phenol present in an amount based on total amount of the non-aqueous inkjet ink that is no less than 0.05 mass % and no more than 2 mass %. 
     
     
         7 . The non-aqueous inkjet ink according to  claim 1 , wherein the pigment is a chelate azo pigment, and wherein the radical polymerization inhibitor is a hindered amine present in an amount based on total amount of the non-aqueous inkjet ink that is no less than 0.05 mass % and no more than 2 mass %. 
     
     
         8 . The non-aqueous inkjet ink according to  claim 1 , wherein the pigment is carbon black, and wherein the radical polymerization inhibitor is a hindered amine present in an amount based on total amount of the non-aqueous inkjet ink that is no less than 0.05 mass % and no more than 2 mass %. 
     
     
         9 . An ink set of inkjet inks, comprising:
 a combination of non-aqueous inkjet inks according to  claim 1  having respective colors and including at least:   a cyan ink having a cyan color;   a magenta ink having a magenta color;   a yellow ink having a yellow color; and   a black ink having a black color.