Kao Corporation

Yuki Suzuki

Teruyuki Fukuda

Satoshi Kunii

Satoshi Tanaka

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.

Aqueous pigment dispersion

The present invention relates to a liquid composition for ink-jet printing which is capable of forming a protective film on a liquid ejection head of an ink-jet type to enhance insulating properties for the liquid ejection head, an image-forming method, a method of forming the protective film, a storing method, and a use of the liquid composition. The present invention provides [1] a liquid composition for ink-jet printing which contains not less than 0.01% by mass and not more than 1.50% by mass of a compound represented by the following formula (1) or a salt thereof, not less than 0.05% by mass and not more than 35% by mass of a compound represented by the following formula (2), and water, [2] an ink-jet image-forming method including the step of ejecting the liquid composition for ink-jet printing according to the above [1] from a liquid ejection head of an ink-jet type including an ejection energy-generating element to form characters or images, [3] a method of forming a protective film on a liquid ejection head of an ink-jet type including an ejection energy-generating element, including the step of applying a voltage to the ejection energy-generating element under such a condition that the ejection energy-generating element is allowed to contact with the liquid composition according to the above [1], [4] a method of storing a liquid ejection head of an ink-jet type including an ejection energy-generating element, including the steps of applying a voltage to the ejection energy-generating element under such a condition that the ejection energy-generating element is allowed to contact with the liquid composition according to the above [1], and filling the liquid ejection head with an ink after the step of applying a voltage, and [5] a use of the liquid composition according to the above [1], as a filling liquid or an ink;R&#x2014;O-(AO)(CHCHO)&#x2014;B&#x2014;COOH&#x2003;&#x2003;(1), andR&#x2014;O-(AO)(CHCHO)&#x2014;H&#x2003;&#x2003;(2).

Inkjet liquid composition

The present invention relates to [1] a pigment water dispersion containing pigment-containing crosslinked polymer particles, in which a crosslinked polymer in the particles is a polymer that is crosslinked with a crosslinking agent represented by the general formula (1), and [2] a process for producing a pigment water dispersion containing pigment-containing crosslinked polymer particles, including the following steps (1) and (2): Step (1): subjecting a pigment mixture containing a pigment, a water-dispersible polymer and water to dispersion treatment, thereby obtaining an aqueous pigment dispersion solution containing pigment-containing polymer particles; and Step (2): mixing the aqueous pigment dispersion solution obtained in the step (1) and a crosslinking agent represented by the general formula (1) to react the water-dispersible polymer with the crosslinking agent, thereby obtaining a pigment water dispersion containing pigment-containing crosslinked polymer particles.

The present invention relates to [1] a pigment water dispersion containing pigment-containing crosslinked polymer particles, in which a crosslinked polymer in the particles is a polymer that is crosslinked with a compound represented by the general formula (1), and the pigment is a carbon black, and [2] a process for producing a pigment water dispersion containing pigment-containing crosslinked polymer particles, including the following steps: Step (1): subjecting a pigment mixture containing a water-dispersible polymer, a pigment and water to dispersion treatment, thereby obtaining an aqueous pigment dispersion solution containing pigment-containing polymer particles; and Step (2): mixing the aqueous pigment dispersion solution obtained in the step (1) and a compound represented by the general formula (1) to react the water-dispersible polymer with the compound to prepare a crosslinked polymer, thereby obtaining the pigment water dispersion containing pigment-containing crosslinked polymer particles.

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Wakayama, Japan

Yuki Suzuki