Process for coloring aluminum and aluminum alloys

Claim 2

A PROCESS FOR COLORING ALUMINUM AND ALUMINUM ALLOYS, WHICH COMPRISES: ANODICALLY OXIDIZING A MEMBRANE OF ALUMINUM OR AN ALUMINUM ALLOY AT A TEMPERATURE OF FROM 15* - 35*C IN A SOLUTION CONTAINING FROM 0.1 - 30% BY WEIGHT OF A PHOSPHOROUS OXIDE ACID OR AN ACID MIXTURE OF A PHOSPHOROUS OXIDE ACID AND FROM 50 TO 150% BY WEIGHT OF A SECOND ACID BASED ON THE AMOUNT OF PHOSPHOROUS OXIDE ACID USED, WHEREIN THE TOTAL CONCENTRATION OF SAID ACID MIXTURE RANGES FROM 0.1 - 30% BY WEIGHT AND TREATING SAID MEMBRANE WITH AN AQUEOUS PIGMENT DISPERSION CONSISTING ESSENTIALLY OF WATER, A PIGMENT AND A DISPERSING AGENT, WHEREBY THE PIGMENT IS IMPREGNATED INTO THE POROUS SURFACE OF THE MEMBRANE.

Claim 3

The process of claim 1, wherein an electric current is passed through the aqueous pigment dispersion.

Claim 4

The process of claim 1, wherein the porous anodically oxidized membrane is treated with the aqueous pigment dispersion and then sealed.

Claim 5

The pRocess of claim 1, wherein said membrane impregnated with a pigment is coated with a coating composition.

Claim 6

The process of claim 1, wherein the anodic oxidation process is conducted together with the adsorption of the pigment in said acid solution containing said pigment dispersion.

Claim 7

The process of claim 1, wherein said aluminum alloy is an alloy of aluminum and another metal selected from the group consisting of copper, silicon, iron, manganese, magnesium, zinc, chromium, titanium, lead, nickel, bismuth and mixtures thereof.

Claim 8

The process of claim 1, wherein said phosphorous oxide acid is selected from the group consisting of orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid and polymetaphosphoric acid.

Claim 9

The process of claim 1, wherein said second acid in said acid mixture is selected from the group consisting of sulfuric acid, chromic acid, boric acid, oxalic acid, sulfamic acid, malonic acid, sulfosalicylic acid, maleic acid, citric acid, tartaric acid, phthalic acid, benzenesulfonic acid, succinic acid, lactic acid or mixtures thereof.

Claim 10

The process of claim 1, wherein the concentration of the pigment having an average particle diameter in the range of 0.01 - 3.0 Mu in a solution of a pH from 1 - 11 is in a range of 0.2 - 30%.

Claim 11

The process of claim 1, wherein said aqueous pigment dispersion is applied by a dip method.

Claim 12

The process of claim 1, wherein said aqueous pigment dispersion is applied by a spray method.

Claim 13

A colored aluminum or aluminum alloy product produced by a process, which comprises the steps of: anodically oxidizing a membrane of aluminum or an aluminum alloy at a temperature of from 15* - 35*C in a solution containing from 0.1 - 30% by weight of a phosphorous oxide acid or an acid mixture of a phosphorous oxide acid and from 50 to 150% by weight of a second acid based on the amount of phosphorous oxide acid used, wherein the total concentration of said acid mixture ranges from 0.1 - 30% by weight and treating said membrane with an aqueous pigment dispersion consisting essentially of water, pigment and a dispersing agent, whereby the pigment is impregnated into the porous surface of the membrane.

Claim 14

A colored aluminum or aluminum alloy product produced by a process, which comprises the steps of: anodically oxidizing a membrane of aluminum or an aluminum alloy at a temperature of from 15* - 35*C in a solution containing from 0.1 - 30% by weight of a phosphorous oxide acid or an acid mixture of a phosphorous oxide acid and from 50 to 150% by weight of a second acid based on the amount of phosphorous oxide acid used, wherein the total concentration of said acid mixture ranges from 0.1 - 30% by weight and treating said membrane with an aqueous pigment dispersion consisting essentially of water, pigment and a dispersing agent, whereby the pigment is impregnated into the porous surface of the membrane.

Claim 15

The colored aluminum or aluminum alloy product of claim 12 which is coated with a layer of resin.