The present invention provides a process for producing a fine organic pigment which is capable of efficiently atomizing a raw material organic pigment, and excellent in productivity of the fine organic pigment. The present invention relates to a process for producing a fine organic pigment which includes the step of kneading a mixture prepared by compounding a raw material organic pigment, a water-soluble inorganic salt, a water-soluble organic solvent and a resin, in which the resin is a copolymer produced by copolymerizing an aromatic ring-containing ethylenically unsaturated monomer (A), a carboxy group-containing ethylenically unsaturated monomer (B) and an ethylenically unsaturated monomer (C) containing a polyethyleneoxide chain having an average molar number of addition of ethyleneoxide of not less than 1 and not more than 50.

The present invention provides the following process for producing a fine organic pigment which is capable of producing the fine organic pigment that has a very small primary particle size and is excellent in filtering property even in a cleaning step, and a fine organic pigment produced by the process; a process for producing a dispersion using the fine organic pigment, and a dispersion produced by the process; and a process for producing an ink using the dispersion. The present invention relates to [1] a process for producing a fine organic pigment, including steps 1 and 2: step 1: kneading a mixture prepared by compounding a raw material organic pigment, a water-soluble inorganic salt, a water-soluble organic solvent and a compound represented by the following formula (1) with each other, the compound being compounded in an amount of not less than 0.8 part by mass and not more than 18.0 parts by mass on the basis of 100 parts by mass of the raw material organic pigment: R.sup.1O(PO).sub.m(EO).sub.nA (1); and step 2: subjecting the mixture obtained in the step 1 to cleaning treatment with an aqueous solvent and then to filtration, [2] a fine organic pigment produced by the process according to the above aspect [1], [3] a dispersion produced using the fine organic pigment according to the above aspect [2], [4] a process for producing a paste of a fine organic pigment, including the above step 1 and 2, [5] a process for producing a dispersion, including step 3 of subjecting the paste of the fine organic pigment produced by the process according to the above aspect [4], an organic solvent and water to dispersing treatment, and [6] a process for producing an ink, including step 4 of mixing the dispersion produced by the process according to the above aspect [5] with at least one material selected from the group consisting of water and an organic solvent.

A method for producing an aqueous pigment dispersion liquid, including: a kneading step of kneading a mixture of a quinacridone pigment (a), a pigment derivative (b), an organic high-molecular compound having an anionic group (c), a basic compound (d), and an acetylene glycol surfactant (e) in a closed kneader to prepare a pigment-kneaded material having a solid content in the range of 50% to 80% by mass; and a step of diluting the pigment-kneaded material with an aqueous medium. A method for producing a water-based ink for ink jet recording, including a step of diluting the aqueous pigment dispersion liquid with an aqueous medium.

Subject matter are aqueous, low-VOC/SVOC universal pigment preparations comprising a pigment component; a water-soluble, nonionic, surface-active additive comprising a copolymer formed from a vinyl monomer and from an ethylenically unsaturated monomer selected from the group consisting of monocarboxylic esters, dicarboxylic esters, monocarboxamides, and dicarboxamides, the vinyl monomer and/or the ethylenically unsaturated monomer containing an N-containing group with pigment affinity; a phosphoric or phosphonic ester, and optionally customary additives. The aqueous pigment preparations are suitable for the coloring of inks, paints, and renders, especially in metering systems at the point of sale or in in-plant tinting systems.

Novel, nano-structured particles are formed by introducing a selected solid of interest into a structured fluid matrix formed by a dispersion of a small molecule host vessel components, such as a native or modified polysaccharide, cavitand, simple sugar, disaccharide, simple polyol or other similarly structured molecule known to be useful as a host vessel, in an acidic medium or other solvent, whereby the particle size of the introduced solid is reduced and or limited in the structured fluid matrix, by incorporation into or attachment to, the host vessel. The simple, one-batch mixing process results in stabilized colloidal dispersions of the nanoparticles of a variety of solids of varying scope and function and useful in a wide variety of applications, including without limitation ceramic materials, such as hexagonal boron nitride.

A method of producing organic pigment microparticles includes: Step 1 of precipitating organic pigment microparticles by mixing an organic pigment raw material liquid in which an organic pigment raw material is mixed with a solvent, and a precipitation solvent for precipitating the organic pigment microparticles from the organic pigment raw material liquid in a thin film fluid formed by introducing the organic pigment raw material liquid and the precipitation solvent in a space between at least two processing surfaces which are disposed so as to face each other, being capable of approaching to and separating from each other, at least one of which rotates relatively to the other; and Step 2 of coating at least a part of the organic pigment microparticles with an oxide coating; wherein the oxide coating is optically colorless and transparent, and Step 1 and Step 2 are performed out continuously in the thin film fluid.

Subject matter are aqueous, low-VOC/SVOC universal pigment preparations comprising a pigment component, a water-soluble, anionic, surface-active additive from the group of the homo- and copolymers of ethylenically unsaturated monocarboxylic or dicarboxylic acids, which may further comprise, in copolymerized form, vinyl monomers containing no acid function, and of the salts of these homo- and copolymers, the homo- and copolymers being at least partly esterified with a polyether alcohol or a derivative thereof, and comprising a phosphoric or phosphonic ester, and optionally customary additives. The aqueous pigment preparations are suitable for the coloring of inks, paints, and renders, especially in metering systems at the point of sale or in in-plant tinting systems.

Novel, nano-structured particles are formed by introducing a selected solid of interest into a structured fluid matrix formed by a dispersion of a small molecule host vessel components, such as a native or modified polysaccharide, cavitand, simple sugar, disaccharide, simple polyol or other similarly structured molecule known to be useful as a host vessel, in an acidic medium or other solvent, whereby the particle size of the introduced solid is reduced and or limited in the structured fluid matrix, by incorporation into or attachment to, the host vessel. The simple, one-batch mixing process results in stabilized colloidal dispersions of the nanoparticles of a variety of solids of varying scope and function and useful in a wide variety of applications, including without limitation ceramic materials, such as hexagonal boron nitride.

The present invention relates to [1] a process for producing a fine organic pigment, including step 1 of kneading a mixture prepared by compounding a raw material organic pigment, a water-soluble inorganic salt and a water-soluble organic solvent; and step 2 of subjecting the kneaded mixture obtained in the step 1 to cleaning treatment with an aqueous solvent and then to filtration treatment, in which before or after kneading the mixture in the step 1 and before subjecting the kneaded mixture to filtration treatment in the step 2, a sulfonic acid salt dispersant is compounded in an amount of not less than 0.8 part by mass and not more than 8.0 parts by mass on the basis of 100 parts by mass of the raw material organic pigment; [2] a process for producing a dispersion, including step 3 of subjecting a pigment mixture containing the fine organic pigment obtained by the production process according to the above [1], an organic solvent and water to dispersion treatment; and [3] a process for producing an ink, including step 4 of mixing the dispersion obtained by the production process according to the above [2] with at least one medium selected from the group consisting of water and an organic solvent.

Novel, nano-structured particles are formed by introducing a selected solid of interest into a structured fluid matrix formed by a dispersion of a small molecule host vessel components, such as a native or modified polysaccharide, cavitand, simple sugar, simple polyol or other similarly structured molecule known to be useful as a host vessel, in an acidic medium or other solvent, whereby the particle size of the introduced solid is reduced and or limited in the structured fluid matrix, by incorporation into or attachment to, the host vessel. The simple, one-step mixing process results in stabilized colloidal dispersions of the nanoparticles useful in a wide variety of applications.