Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from vegetable oils or vegetable oil-derived compounds; near infrared absorbing fine particles in an amount of 2 mass % or more and 25 mass % or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XB.sub.a (wherein element X is at least one or more kinds selected from a group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr, and Ca, satisfying 4.0a6.2); and a dispersant soluble in the solvent and having a fatty acid in its structure, wherein viscosity is 180 mPa/S or less, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid. Also provided is an anti-counterfeit printed matter excellent in anti-counterfeit effect due to the printed matter containing the near infrared absorbing fine particles.

Provided is a near infrared absorbing fine particle dispersion liquid, which can be applied to offset printing, including: a solvent of one or more kinds selected from vegetable oils and vegetable oil-derived compounds; near infrared absorbing fine particles of one or more kinds selected from 10 mass % more and 25 mass % or less of a composite tungsten oxide expressed by M.sub.xW.sub.yO.sub.z, and/or a tungsten oxide having a Magneli phase expressed by a general formula W.sub.yO.sub.z; and a dispersant soluble in the solvent and having a fatty acid in its structure, wherein a viscosity is 180 mPa/S or less.

A modified clay is disclosed which is characterized by an average shape factor less than 60, a sediment void volume greater than 48%, and containing less than 30% by mass of particles less than 1 micron in diameter. The modified clay may be used in products including coatings, paints, and other products where clays and pigments are used.

There is provided a method for producing a carbon material dispersion, which makes it possible to simply produce a dispersion in which a carbon material containing a carbon nanotube is dispersed favorably without substantially producing a coarse aggregate, the dispersion excellent in viscosity stability. The method is a method for producing a carbon material dispersion, the method including a step (1) of subjecting a raw material containing: a carbon material containing a carbon nanotube; a dispersant; and a liquid medium to a stirring treatment to obtain a wetted mixture, and a step (2) of subjecting the wetted mixture to a dispersion treatment using a high-pressure homogenizer, wherein the high-pressure homogenizer is at least any one of a high-pressure homogenizer (A1) employing a system of allowing the wetted mixtures jetted by pressurization to collide with each other to form fine particles and a high-pressure homogenizer (A2) employing a system of introducing the wetted mixture pressurized into a collision chamber to form fine particles, and a two-stage dispersion treatment in which the inner diameter of the ejection nozzle and the treatment pressure are changed is performed.

There is provided a carbon material dispersion in which a carbon material containing a carbon nanotube is dispersed favorably without substantially producing a coarse aggregate irrespective of liquid compositions and dispersion methods, the carbon material dispersion excellent in viscosity stability. The carbon material dispersion excluding one that contains a volatile salt contains: a carbon material containing a carbon nanotube; a liquid medium; and a dispersant. The content of the dispersant in terms of solid content based on 100 parts by mass of the carbon material is 204 parts by mass or less, and when a dilute dispersion is obtained by diluting the carbon material dispersion with a diluent comprising the liquid medium such that absorbance at a wavelength W.sub.M, which is a median value of an arbitrary wavelength W.sub.L within a range of 350 to 550 nm and an arbitrary wavelength W.sub.H within a range of 650 to 850 nm, is 1.80.02, a ratio of absorbance A.sub.L at the wavelength W.sub.L to absorbance A.sub.H at the wavelength W.sub.H, (A.sub.L/A.sub.H), is 1.60 or more for the dilute dispersion.

A particle material that has high dispersibility in a dispersion medium such as toluene having high hydrophobicity, and a slurry composition in which the particle material is used, are provided for solving the problem. A surface-modified particle material of the present invention includes: a particle material formed of an inorganic material; and a surface treatment agent formed of a silane compound having a first functional group that has any of C, N, and O atoms away over five or more atoms from Si to which an alkoxide is bound, the surface treatment agent allowing surface treatment of the particle material in such an amount that a degree of hydrophobicity becomes not less than 30%. Dispersibility is enhanced also in a dispersion medium having high hydrophobicity in a case where a functional group having a predetermined structure is introduced so as to impart predetermined or higher hydrophobicity.

A method of making a liquid electrophotographic (LEP) paste is disclosed herein. A base paste is made by forming a dispersion of a pigment and a non-polar carrier, adding a transparent resin dispersion to the pigment dispersion to form a dispersion mixture, and homogenizing the dispersion mixture. The transparent resin dispersion includes a polymer dispersed in a non-aqueous carrier. The homogenizing may be accomplished by agitating the dispersion mixture at a frequency of less than 1 kHz, thereby forming the paste.

A method of forming a passivated pigment slurry includes combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface. After combining, the method includes mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry. The coated pigment-resin slurry includes the resin and a coated pigment including the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface. The method further includes reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form the passivated pigment slurry. The passivated pigment slurry includes the resin and a passivated pigment including the plurality of flakes each coated with a second layer disposed on the first layer.

The invention relates to a method for improving rheological properties of an aqueous pigment slurry. In the method dispersion agent is added to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added. The dispersion agent comprises styrene acrylate copolymer. The invention also relates to a dispersion agent for a pigment slurry comprising a first component comprising styrene acrylate copolymer and a second component comprising a conventional dispersion agent, such as a straight-chain polyacrylate.

The present invention provides a magnetic multilayer pigment flake and a magnetic coating composition that are relatively safe for human health and the environment. The pigment flake includes one or more magnetic layers of a magnetic alloy and one or more dielectric layers of a dielectric material. The magnetic alloy is an iron-chromium alloy or an iron-chromium-aluminum alloy, having a substantially nickel-free composition. The coating composition includes a plurality of the pigment flakes disposed in a binder medium.