Yoshida Kogyo K.k.

Sakura Color Products Corporation

Bridgestone Corporation

Seishiro Ito

Hatsuo Hirono

Hideo Fukui

Norio Nakada

Hiroshi Inoue

Shigeyasu Inoue

Michitaka Takeshita

Tatsuhiko Ihara

Mitsuo Kiboku

A pigment dispersion composition for fill-in coloration of an aluminum or aluminum alloy oxide film is provided, which comprises at least a pigment, a pigment dispersant, a water-soluble organic solvent, water, and a water-soluble amine and/or a derivative thereof. Pigment particles of the pigment dispersion composition are filled in micropores of the aluminum oxide film to a great depth, so that a vivid color film having excellent weatherability and fastness can be provided. In addition, the composition offers a high adaptability for repetitive coloration, and allows pigment deposited on the film surface other than in the micropores to be washed away by simple immersion in still water or running water.

Electrophoretic coloring composition

The present invention discloses a pigment dispersion composition for depositing a multiplicity of pores existing in anodic oxide films formed on a surface of an aluminum or aluminum alloy material by way of electrophoresis for coloration, the pores being preliminarily enlarged to have a diameter of 50 nm to 250 nm. The pigment dispersion composition comprises water, a pigment dispersant and a pigment. The pigment dispersed in the pigment dispersion composition has a median particle size of not greater than 250 nm in a particle-size distribution thereof with not greater than 30% of the pigment particles being impassable through a sieve having a mesh size of 300 nm. The pigment dispersion composition is useful for coloration of the anodic oxide films, and has excellent repeated-coloration characteristics.

Pigment dispersion composition

A fast and brightly colored oxide film of aluminum which excels in durability and allows no separation of pigment is produced by using an aqueous dispersion of an organic pigment or carbon black finely divided to a size in the range between 3 and 150 nm, forming on a surface of an aluminum member an anodic oxide film containing pores larger in diameter than the ordinary pores, and causing the organic pigment or carbon black to migrate and deposit in the pores of the oxide film by means of electrophoresis. The formation of the anodic oxide film containing the pores larger in diameter than the ordinary pores is accomplished in the first method by subjecting the aluminum member to anodic oxidation at a high voltage in an aqueous solution of acid. In the second method, the anodic oxide film is subjected either to a treatment of immersion in an aqueous solution of at least one acid selected from among phosphoric acid, sulfuric acid, oxalic acid, and sulfamic acid or to a combination treatment of immersion and AC electrolysis repeated in a prescribed number of cycles in the solution, to enlarge the pores in the anodic oxide film.

Method for production of colored article of aluminum or aluminum alloy

Durable and clear blue color of freely controlled density can be expeditiously and efficiently impated to an anodic oxide film of aluminum by a method which comprises forming the anodic oxide film on the aluminum or aluminum alloy, then subjecting the aluminum or aluminum alloy to AC electrolysis in a bath containing an inorganic ferrous salt as a main component thereof thereby inducing deposition of iron in the pores of the oxide film, and subsequently placing the aluminum or aluminum alloy as an anode in a bath containing hexacyano iron (II) acid salt as a main component thereof and subjecting the same to DC electrolysis therein. In the alternative method, the pore-widening treatment is added next to said step of anodic oxidation. The pore-widening treatment is effected by immersing the aluminum or aluminum alloy in sulfuric acid or phosphoric acid or electrolyzing the same in phosphoric acid or a mixed solution of phosphoric acid and sulfuric acid.

Method for impartation of blue color to aluminum or aluminum alloy

An aluminum or aluminum alloy material is subjected to anodic oxidation, then to a treatment of electrophoresis in a bath containing a hexacyanoferrate (II) or hexacyanoferrate (III), and subsequently to a treatment of immersion in a bath containing at least one metal salt selected from the group consisting of salts of Fe, Ni, Co, Cu, Zn, Cd, Ba, Tl, and Mg and at least one electrolyte selected from the group consisting of sodium sulfate, potassium sulfate, sodium chloride, and potassium chloride. Consequently, a coloring compound formed by the reaction of the aforementioned hexacyanoferrate (II) or hexacyanoferrate (III) with the aforementioned metal salt is deposited in the receding parts of micropores of an anodic oxide coating, with the result that the aluminum or aluminum alloy material is endowed with a durable color.

Method of coloring aluminum or aluminum alloy material

A dispersion improved carbon black compounded rubber composition comprises a rubber component and a reinforcing carbon black in an amount of from 30 to 150 parts by weight with respect to 100 parts by weight of the rubber component. The rubber component is selected from a group consisting of a natural rubber, synthetic isoprene rubber and a mixture thereof, or a blend of this rubber component with a diene base synthetic rubber other than this rubber component. The reinforcing carbon black has a specific surface area of from 70 to 200 m.sup.2 /g when measured by a nitrogen adsorption method and a DBP value of from 80 to 130 ml/100 g, and is obtained by introducing mainly phenolic hydroxide groups into the surface of the carbon black through plasma treatment at low temperatures or by introducing carboxyl groups and the phenolic hydroxide groups thereinto through plasma treating at low temperatures and neutralizing the thus introduced acid groups.

Growing community of inventors

Ikoma, Japan

Seishiro Ito