Kao Corporation

Nippon Paper Industries Co., Ltd.

Takayuki Suzuki

Yasufumi Ueda

Hirotaka Takeno

Kaname Mitsuyoshi

Koji Kutsuwa

Teruyuki Fukuda

Takahiro Yoshikawa

Erika Maekawa

Masaaki Nakano

Takako Yamamoto

The present invention relates to a cleaning liquid for a water-based ink that contains a pigment and a water-insoluble polymer, said cleaning liquid containing (A) an acetylene glycol having an average molar number of addition of EO of 0 to 2 mol, (B) at least one compound selected from the group consisting of an acetylene glycol having an average molar number of addition of EO of not less than 4 mol and a polyethylene glycol alkyl ether containing an alkyl group having not less than 8 carbon atoms, (C) a water-soluble organic solvent and water, in which the water-soluble organic solvent (C) contains at least one water-soluble organic solvent having a boiling point of not lower than 90&#xb0; C.; a boiling point of the water-soluble organic solvent (C) is not higher than 250&#xb0; C. in terms of a weighted mean value thereof; and a content of the water-soluble organic solvent (C) in the cleaning liquid is not more than 20% by mass; a process for producing the cleaning liquid; and a method of cleaning a water-based ink using the cleaning liquid.

Cleaning liquid for aqueous ink comprising an acetylene glycol-based surfactant

The present invention relates to a pigment water dispersion containing a pigment, a crosslinked polymer and water, in which the crosslinked polymer is prepared by crosslinking a carboxy group-containing polymer with a crosslinking agent, and has an acid value of not less than 70 mgKOH/g and not more than 300 mgKOH/g; and the pigment water dispersion further contains a formaldehyde-releasing compound. The pigment water dispersion of the present invention is excellent in storage stability even when being stored under high-temperature conditions for a long period of time.

Aqueous pigment dispersion

The present invention relates to a cleaning liquid for a water-based ink that contains a pigment and a water-insoluble polymer, said cleaning liquid containing (A) a surfactant, (B) a water-soluble organic solvent containing (b-1) diethylene glycol monoisopropyl ether, and water, in which the surfactant (A) contains at least one compound selected from the group consisting of (a-1) an acetylene glycol or an ethyleneoxide adduct of the acetylene glycol, and (a-2) a polyethylene glycol alkyl ether containing an alkyl group having not less than 8 carbon atoms or a polyethylene glycol aryl ether containing an aryl group having not less than 6 carbon atoms, and a content of the water-soluble organic solvent (B) in the cleaning liquid is from 5 to 30% by mass; and a method of cleaning a water-based ink using the cleaning liquid.

Cleaning liquid for aqueous ink

An inkjet recording medium having an ink receiving layer containing an inorganic pigment, starch, and copolymer latex on at least one surface of a base, characterized in that the inorganic pigment contains engineered calcium carbonate and kaolin, an amount of the engineered calcium carbonate is from 50% by weight or more to less than 80% by weight and an amount of the kaolin is from 10% by weight or more to less than 50% by weight with respect to a total amount of the inorganic pigment, and from 1 parts by weight or more to 10 parts by weight or less of an organic pigment having a glass transition temperature (Tg) of 20&#xb0; C. or more is contained in the ink receiving layer with respect to 100 parts by weight of the inorganic pigment.

Inkjet recording medium and inkjet recording method

The present invention relates to a water-based ink that exhibits excellent ejection properties, and can be prevented from suffering from reduction in a dot size of the ink during a drying step thereof even when printed on a low-water absorbing recording medium, and is capable of obtaining printed characters or images having excellent uniformity, as well as an ink-jet printing method using the water-based ink. The water-based ink includes a pigment, a water-insoluble polymer, an acetylene glycol-based nonionic surfactant (A) having HLB of not less than 0 and not more than 5, a nonionic surfactant (B) having HLB of not less than 6 and not more than 20, a polyether-modified silicone (C) having a kinematic viscosity of not less than 30 mm/s and not more than 190 mm/s as measured at 25&#xb0; C. and an organic solvent (D), in which a weighted mean value of a boiling point of the organic solvent (D) is not lower than 150&#xb0; C. and not higher than 230&#xb0; C.

Water-based ink

An inkjet recording method for printing an inkjet recording medium comprising an ink-receiving layer containing inorganic pigment, starch and copolymer latex on a surface of a base with inkjet ink as aqueous pigment ink, a content of the inorganic pigment being 10 g/mor more to 35 g/mor less in the ink-receiving layer, and a content of calcium carbonate being from 80% by weight or more to 100% by weight or less, the inkjet ink containing one or more selected from self dispersed pigment and pigment containing water-insoluble polymer particles, from 10% by weight or more to 48% by weight or less of a water-soluble organic solvent A having a boiling point of 230&#xb0; C. or less, from 0% by weight or more to 5.0% by weight or less of a water-soluble organic solvent B having a boiling point of 280&#xb0; C. or more, from 42% by weight or more to 70% by weight or less of water.

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Barcelona, Spain

Takayuki Suzuki