Kao Corporation

Tsuyoshi Egawa

Kaname Mitsuyoshi

Tomohiko Nagano

Yusuke Shimizu

Katsuhisa Inoue

Kyoichi Shirota

Yasuyuki Mimura

Shimpei Nishimura

The present invention relates to [1] a water-based ink containing an azomethine metal complex pigment (A), an aromatic group-containing polymer (B), an organic solvent (D) and water, in which a mass ratio of the azomethine metal complex pigment (A) to the aromatic group-containing polymer (B) [(A)/(B)] is not less than 1.4 and not more than 4, and the aromatic group-containing polymer (B) is a crosslinked polymer obtained by crosslinking an aromatic group-containing polymer (b) having an acid value of not less than 80 mgKOH/g and not more than 400 mgKOH/g with a water-insoluble polyfunctional epoxy compound (c), said water-based ink being excellent in storage stability and maintenanceability, and [2] a process for producing a pigment water dispersion liquid of particles of the aromatic group-containing polymer (B) containing the azomethine metal complex pigment (A).

Aqueous ink

The present invention relates to [1] a process for producing a pigment water dispersion liquid of polymer particles containing an azomethine metal complex pigment (A), said process including the step of subjecting a mixture containing the azomethine metal complex pigment (A), an uncrosslinked aromatic group-containing polymer (b) and water to dispersion treatment using a medialess disperser at an accumulated input energy of not more than 5.0 kWh/kg, [2] a pigment water dispersion liquid containing an azomethine metal complex pigment (A) and a polymer dispersant (B), in which in an optical absorption spectrum of the pigment water dispersion liquid, a ratio of a maximum absorbance (A1) in a wavelength range of not less than 440 nm and less than 465 nm to a maximum absorbance (A2) in a wavelength range of not less than 420 nm and less than 440 nm [(A1)/(A2)] is not less than 1.000, and [3] a water-based ink for ink-jet printing, containing the aforementioned pigment water dispersion liquid.

Production method for pigment aqueous dispersion

The present invention relates to an ink set for ink-jet printing which contains at least a water-based ink (I) and a water-based ink (II) in which the water-based ink (I) contains a pigment (A1) having a barbituric acid-derived structure, and the water-based ink (II) contains a diketopyrrolopyrrole pigment (A2), an ink-jet printing method using the ink set, and an ink-jet printed material.

Ink set for inkjet recording

The present invention relates to [1] a water-based ink for ink-jet printing which can be prevented from suffering from increased viscosity and flocculation of the ink upon storage thereof even when used in the form of a system containing a large amount of a solvent, said water-based ink for ink-jet printing containing crosslinked polymer particles containing a pigment having an indanthrone skeleton, an organic solvent and water, in which a crosslinking rate of the crosslinked polymer is not less than 10 mol % and not more than 90 mol %, and a content of the organic solvent in the water-based ink is not less than 30% by mass and not more than 65% by mass, and [2] an ink-jet printing method including the steps of loading the water-based ink as described in the above [1] to an ink-jet printing apparatus, and ejecting the water-based ink in the form of droplets of the ink onto a printing medium to form characters or images on the printing medium.

Water-based ink for ink-jet recording

The present invention provides a novel quaternary ammonium salt compound that is excellent in atomization of a pigment dispersion and storage stability, a dispersant containing the quaternary ammonium salt compound, a use of the quaternary ammonium salt compound, and a process for producing the quaternary ammonium salt compound. The present invention relates to [1] a quaternary ammonium salt compound represented by the general formula (I); [2] a dispersant containing the compound of the above [1]; [3] a use of the compound of the above [1] for dispersing a pigment; and [4] a process for producing a quaternary ammonium salt compound represented by the general formula (I), including a step of reacting a halogenated alkyl ester compound represented by the general formula (II) with a polyamine compound represented by the general formula (III).

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Izumiotsu, Japan

Tsuyoshi Egawa