The present invention provides a pigment water dispersion that is excellent in dispersion stability, and also excellent in ejection properties even when used as an ink for ink-jet printing. The present invention relates to [1] a pigment water dispersion containing (A) a pigment, (B) a carboxy group-containing crosslinked polymer and (C) an alkyl group-containing ethanolamine having a pKa of not less than 8.7, [2] a water-based ink containing the pigment water dispersion, an organic solvent and a surfactant, and [3] a process for producing a pigment water dispersion, including step (I) of subjecting a mixture containing the pigment (A), a crosslinkable polymer, the aforementioned ethanolamine (C), an organic solvent and water to dispersion treatment, thereby obtaining a dispersion of pigment-containing polymer particles containing the pigment (A) and the crosslinkable polymer that is adhered onto the pigment (A); step (II) of removing the organic solvent from the obtained dispersion, thereby obtaining a water dispersion of the pigment-containing polymer particles; and step (III) of further subjecting the polymer to crosslinking reaction with a crosslinking agent, thereby obtaining the pigment water dispersion containing pigment-containing crosslinked polymer (B) particles.

The present invention provides a pigment water dispersion that is excellent in dispersion stability, and also excellent in ejection properties even when used as an ink for ink-jet printing. The present invention relates to [1] a pigment water dispersion containing (A) a pigment, (B) a carboxy group-containing crosslinked polymer and (C) an alkyl group-containing ethanolamine having a pKa of not less than 8.7, [2] a water-based ink containing the pigment water dispersion, an organic solvent and a surfactant, and [3] a process for producing a pigment water dispersion, including step (I) of subjecting a mixture containing the pigment (A), a crosslinkable polymer, the aforementioned ethanolamine (C), an organic solvent and water to dispersion treatment, thereby obtaining a dispersion of pigment-containing polymer particles containing the pigment (A) and the crosslinkable polymer that is adhered onto the pigment (A); step (II) of removing the organic solvent from the obtained dispersion, thereby obtaining a water dispersion of the pigment-containing polymer particles; and step (III) of further subjecting the polymer to crosslinking reaction with a crosslinking agent, thereby obtaining the pigment water dispersion containing pigment-containing crosslinked polymer (B) particles.

The ink-jet ink of the present invention comprises a solvent S having an SP value of 9.1-9.4, resin emulsion particles and water. It is preferable that the resin emulsion particles contain a (meth)acrylic polymer. It is also preferable that the resin emulsion particles contain a structural unit derived from styrene. It is also preferable that the solvent S is tripropylene glycol monomethyl ether and/or monoethylene glycol monoisopropyl ether.

The ink-jet ink of the present invention comprises a solvent S having an SP value of 9.1-9.4, resin emulsion particles and water. It is preferable that the resin emulsion particles contain a (meth)acrylic polymer. It is also preferable that the resin emulsion particles contain a structural unit derived from styrene. It is also preferable that the solvent S is tripropylene glycol monomethyl ether and/or monoethylene glycol monoisopropyl ether.

An example of a liquid ink includes a pigment dispersion, a polyurethane dispersion, a polytetrafluoroethylene wax emulsion, a co-solvent, and a balance of water. A particle diameter of a polytetrafluoroethylene wax in the polytetrafluoroethylene wax emulsion is less than 50 nm. Examples of the liquid ink may be incorporated into a thermal inkjet printing system.

An example of a liquid ink includes a pigment dispersion, a polyurethane dispersion, a polytetrafluoroethylene wax emulsion, a co-solvent, and a balance of water. A particle diameter of a polytetrafluoroethylene wax in the polytetrafluoroethylene wax emulsion is less than 50 nm. Examples of the liquid ink may be incorporated into a thermal inkjet printing system.

A radiation-curable ink is provided and includes: a first liquid phase, including a radiation-curable hydrophobic polymerizable compound; and a second liquid phase, including at least one compound selected from a group consisting of water, an aqueous polymerizable compound, an aqueous polymer, and an aqueous non-polymerizable compound. The second liquid phase is emulsified and dispersed in the first liquid phase. And, a three-dimensional object is formed by curing the radiation-curable ink, in which a third liquid phase derived from the second liquid phase and including at least one compound selected from the group consisting of water, the aqueous polymerizable compound, the aqueous polymer, and the aqueous non-polymerizable compound is dispersed as a sea-island structure in a continuous phase of a hydrophobic cured product formed by curing the first liquid phase. A water content of the third liquid phase is 1% by weight or more.

A radiation-curable ink is provided and includes: a first liquid phase, including a radiation-curable hydrophobic polymerizable compound; and a second liquid phase, including at least one compound selected from a group consisting of water, an aqueous polymerizable compound, an aqueous polymer, and an aqueous non-polymerizable compound. The second liquid phase is emulsified and dispersed in the first liquid phase. And, a three-dimensional object is formed by curing the radiation-curable ink, in which a third liquid phase derived from the second liquid phase and including at least one compound selected from the group consisting of water, the aqueous polymerizable compound, the aqueous polymer, and the aqueous non-polymerizable compound is dispersed as a sea-island structure in a continuous phase of a hydrophobic cured product formed by curing the first liquid phase. A water content of the third liquid phase is 1% by weight or more.

The present invention provides: a vinyl chloride-based resin emulsion of a polymerization product composed of (A) a polycarbonate urethane oligomer having a number average molecular weight of 5,000 to 50,000 and (B) a monomer composition containing a vinyl chloride monomer, wherein the polycarbonate urethane oligomer (A) having a number average molecular weight of 5,000 to 50,000 is contained in an amount of 40 to 500 parts by mass relative to 100 parts by mass of the monomer composition (B) containing a vinyl chloride monomer; and a method for producing the vinyl chloride-based resin emulsion. The vinyl chloride-based resin emulsion according to the present invention can exhibit excellent water resistance, moisture resistance, high gloss, alcohol resistance, close adhesiveness and film formability at ambient temperature when used in a water-based ink, and can exhibit excellent color developability, water resistance, moisture resistance, color visibility, high gloss and close adhesiveness when used in recording paper, and therefore can be used effectively in a binder for an ink, a coating material and an inorganic substance dispersion, an absorption layer in recording paper, a fiber treating agent, wallpaper in medical facilities and the like.

The present invention provides: a vinyl chloride-based resin emulsion of a polymerization product composed of (A) a polycarbonate urethane oligomer having a number average molecular weight of 5,000 to 50,000 and (B) a monomer composition containing a vinyl chloride monomer, wherein the polycarbonate urethane oligomer (A) having a number average molecular weight of 5,000 to 50,000 is contained in an amount of 40 to 500 parts by mass relative to 100 parts by mass of the monomer composition (B) containing a vinyl chloride monomer; and a method for producing the vinyl chloride-based resin emulsion. The vinyl chloride-based resin emulsion according to the present invention can exhibit excellent water resistance, moisture resistance, high gloss, alcohol resistance, close adhesiveness and film formability at ambient temperature when used in a water-based ink, and can exhibit excellent color developability, water resistance, moisture resistance, color visibility, high gloss and close adhesiveness when used in recording paper, and therefore can be used effectively in a binder for an ink, a coating material and an inorganic substance dispersion, an absorption layer in recording paper, a fiber treating agent, wallpaper in medical facilities and the like.