A method for coating pigment particles is provided, the method comprising heating a polymer resin in a carrier fluid to dissolve the polymer resin; suspending in the carrier fluid white pigment particles to be coated; and cooling the carrier fluid at a rate of 2° C./hr or less to effect precipitation of the polymer resin from the carrier fluid such that a coating of the resin is formed on the pigment particles, thereby producing the white liquid electrophotographic ink composition.

A composition comprising a pigment particle that is coated with a cationic material and isopropyl titanium tri-isostearate. The pigment particle can be included in a cleansing composition for deposition on a surface, such as skin.

The invention provides a method for preparing a dry titanium dioxide product, comprising the steps of: providing a dispersion comprising titanium dioxide particles; treating the titanium dioxide particles with a silane of formula (I):

R.sup.II(OR.sup.I).sub.aORSiX.sub.3  (I)

wherein R is a divalent C1-24 organic group that is carbon-bonded to the silicon atom, R.sup.I is a C2-6 alkylene group, R.sup.II is hydrogen, a C1-16 alkyl group, a C2-16 alkyl ether group, or a C2-12 acyloxy group, X is a hydrolysable group, and a is a number having a value from 3 to 150;
and then drying the dispersion to provide a dry titanium dioxide product.

The dry titanium dioxide product may optionally be dispersed within a vehicle.

The invention relates to a pigment composition for preparing pigmented matt coatings, such as matt paints and printing inks. Further, the invention relates to a process for preparing such pigment composition, and to a coating formulation containing such composition. Finally, the invention is directed to a pigmented matt surface of a substrate, and to the use of the pigment compositions disclosed herein for matting substrates.

A titanium oxide powder of the present invention has a BET specific surface area of 5 m.sup.2/g or higher and 15 m.sup.2/g or lower and contains single-crystalline titanium oxide particles, in which a value (d10/d50) that is obtained by dividing a value (d10), which is obtained when a particle size distribution represented by a cumulative volume percentage of primary particle diameters of the titanium oxide particles is 10%, by a value (d50), which is obtained when a particle size distribution represented by a cumulative volume percentage thereof is 50%, is 0.3 or higher and 1 or lower, an amount of titanium oxide thereof is 99.0% by mass or more, and the titanium oxide powder has an anatase-type crystalline phase.

This powder satisfies requirements 1 and 2.

Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at at least one temperature Ti in a range of −200° C. to 1200° C. A is (a-axis (shorter axis) lattice constant) of a crystal in the powder)/(c-axis (longer axis) lattice constant of the crystal in the powder), and each of the lattice constants is obtained by X-ray diffractometry of the powder. Requirement 2: a particle diameter D50 at a cumulative frequency of 50%, a particle diameter D10 at a cumulative frequency of 10%, and a particle diameter D90 at a cumulative frequency of 90% in a volume-based cumulative particle diameter distribution curve obtained by a laser diffraction scattering method satisfy conditions (I) and (II): (I) D10/D50 is 0.05 or more and 0.45 or less; and (II) 190 is 0.5 μm or more and 70 μm or less.

This powder satisfies requirements 1 and 2.

Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at at least one temperature Ti in a range of −200° C. to 1200° C. A is (a-axis (shorter axis) lattice constant) of a crystal in the powder)/(c-axis (longer axis) lattice constant of the crystal in the powder), and each of the lattice constants is obtained by X-ray diffractometry of the powder. Requirement 2: a particle diameter D50 at a cumulative frequency of 50%, a particle diameter D10 at a cumulative frequency of 10%, and a particle diameter D90 at a cumulative frequency of 90% in a volume-based cumulative particle diameter distribution curve obtained by a laser diffraction scattering method satisfy conditions (I) and (II): (I) D10/D50 is 0.05 or more and 0.45 or less; and (II) 190 is 0.5 μm or more and 70 μm or less.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

The present invention provides a powder surface treatment method comprising (i) a step for mixing 0.001-20 parts by mass of a surface treating agent composition with 100 parts by mass of a power, and (ii) a step for adding an acidic liquid, followed by mixing, wherein the surface treating agent composition contains (a)-(d) below: (a) one or more selected from among an N-acyl amino acid having a carbon chain length of C8-C22 and a salt thereof; (b) one or more selected from among monohydric and polyhydric alcohols; (c) water; and (d) one or more selected from among (dl) an amino acid having an isoelectric point of 7.5-11, and (d2) a compound which generates an ion selected from among an aluminum ion, a magnesium ion, a calcium ion, a zinc ion, a zirconia ion, and a titanium ion, in the surface treating agent composition.