A method for producing dispersions with a defined particle size includes following steps: A) Preparation of a mixed dispersion in a predispersion process, B) introduction of the mixed dispersion into at least one continuously operating separating device, C) separation of the mixed dispersion in the separating device into coarse particles of a coarse-part dispersion and into fine particles of a fine-part dispersion, D) discharging the fine particle dispersion from the separating device into at least one storage tank, E) discharging the coarse particle dispersion from the separating device into at least one disperser, F) grinding the coarse particles of the coarse particle dispersion in the disperser into a dispersed particle mixture and returning the dispersed particle mixture to the mixing tank in the predispersion process, and G) mixing the dispersed particle mixture returned to the predispersion process with the mixing dispersion produced in the predispersion process in the mixing tank.

According to the present invention, provided is a core-shell structured chromic microcapsule having a size of 50-1,500 m, comprising: a core comprising a colorant core (A) and an optional inner color layer (B); and a shell comprising a pressure sensitive destructible wall layer (C) encompassing the core, an optional outer color layer (D) and an optional outermost protective layer (E), wherein the colorant core allows a high content of a colorant to be contained, and the pressure sensitive destructible wall layer comprises carbon dioxide particles and a binder comprising one or more wall-forming materials and one or more lipid-base materials. The chromic microcapsule according to the present invention has high colorant content, has excellent storage durability, maintenance durability and color-hiding property of the inner color layers, is easily destroyed by pushing, rubbing, polishing or scrubbing with the hands or a tool (cotton fabric, sponge or paper) so as to express the color of the inner color layers, and can maintain stability for a long time even if being added into a carrier.

The present invention relates to polyalkylene imine based polymers, which have aliphatic polyester groups attached to the polyalkylenimine backbone via an carboxamide group. The novel polymers are particularly useful as dispersants for pigments, in particular as dispersants for pigments in non-aqueous compositions. The polyalkylene imine based polymers are characterized by having a) a polyalkylene imine backbone; b) at least one aromatic moiety P.1, which is bound to a nitrogen atom of the polyalkylene imine backbone via an carboxamide or carboximide group; and c) at least one aliphatic polyester moiety P.2, which is bound to a nitrogen atom of the polyalkylene imine backbone via an carboxamide group.

The present invention relates to [1] a process for producing a pigment composition, including the step of subjecting a raw material pigment composition containing PY74 and a specific by-product to a treatment with an oxidizing agent, in which a content of the specific by-product in the pigment composition after the treatment on the basis of a content of PY74 in the pigment composition after the treatment is not more than 1,200 mg/kg; [2] a process for producing a pigment composition, including the step of subjecting a raw material pigment composition containing PY74, a specific by-product and water to a treatment with hydrogen peroxide; [3] a method of reducing a content of a specific by-product in a raw material pigment composition containing PY74 and the specific by-product, said method including the step of subjecting the raw material pigment composition to a treatment with an oxidizing agent; and [4] a method of preventing an ink for ink-jet printing from suffering from ejection defects, including the step of compounding the pigment composition produced by any of the aforementioned processes in the ink for ink-jet printing.

A method for preparing a dispersion of nanoparticles of a solid organic dye or pigment in a liquid carrier, the method comprising forming a solution or slurry of the solid organic dye or pigment in an organic or other solvent, and continuously mixing the solution or slurry with the liquid carrier in a counter current or concurrent mixing reactor providing a dispersion of the nanoparticles in the liquid carrier and solvent mixture and, optionally concentrating the dispersion.

A pigment comprising dyed crystalline cellulose particles comprising a crystalline cellulose core having a surface charge, optionally one or more polyelectrolyte layers with alternating charges adsorbed on top of each other on the crystalline cellulose core, the polyelectrolyte layer closest to the core having a charge opposite the surface charge of the core, and at least one organic dye having a charge is provided.

This invention relates to a process for preparing multi-color dispersions and the multi-color dispersions made thereof.

The present disclosure is drawn to aqueous pigment co-dispersions. The co-dispersions include self-dispersed pigment with a chemically modified surface; released surface moieties from the self-dispersing pigment; pigment powder having the released surface moieties associated with pigment powder surfaces; polymeric dispersant; and water.

Provided is a black pigment that enables pattern formation of pixel division layer while suppressing generation of development residue. The black pigment comprises (a) a core containing at least one organic black pigment selected from the group consisting of benzodifuranone-based black pigments, perylene-based black pigments, azo-based black pigments, and isomers thereof and (b) a coating layer containing silica and/or a metal oxide and/or a metal hydroxide.

Provided herein are compositions useful as ink or coatings which contain novel dispersants that are capable of dispersing pigments which are traditionally difficult to disperse while maintaining acceptable levels of viscosity. Use of dispersants as taught herein enables the preparation of a wide variety of inks and coatings having high pigment loading and existing within a conventionally-useful viscosity range.