Coating solution for metal surfaces

Claim 2

An aluminum surface having a uniformly colorless and clear coating which is free of boron and phosphate and is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., said coated aluminum surface having been obtained by contacting such aluminum surface with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine, and glucoheptonate.

Claim 3

An aluminum surface as in claim 1 wherein zirconium is present in the coating solution employed to coat the surface.

Claim 4

An aluminum surface as in claim 2 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 5

An aluminum surface as in claim 1, 2 or 3 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 6

An aluminum surface as in claim 2 wherein the source of zirconium is ammonium fluozirconate.

Claim 7

An aluminum surface as in claim 5 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 8

An aluminum surface as in claim 5 or 6 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 9

An aluminum surface as in claim 2 wherein the source of zirconium is fluozirconic acid.

Claim 10

An aluminum surface as in claim 8 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 11

An aluminum surface as in claim 8 or 9 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 12

An aluminum surface as in claim 2 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 13

An aluminum surface as in claim 11 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 14

An aluminum surface as in claim 11 or 12 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 15

An aluminum surface as in claim 5 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 16

An aluminum surface as in claim 14 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 17

An aluminum surface as in claim 14 or 15 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 18

An aluminum surface as in claim 8 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 19

An aluminum surface as in claim 17 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 20

An aluminum surface as in claim 17 or 18 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 21

An aluminum surface as in claim 2, 5 or 8 wherein the coating solution employed to coat the surface contains from about 0.5×10 -3 moles/liter to about 1.75×10 -3 moles/liter of zirconium and from about 0.3×10 -3 moles/liter to about 1.75×10 -3 moles/liter of polyhydroxy compound.

Claim 22

An aluminum surface as in claim 20 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 23

An aluminum surface as in claim 20 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 24

An aluminum surface as in claim 20 wherein nitric acid is present in the coating solution employed to coat the surface and the solution has a pH of about 3.0 to about 4.0.

Claim 25

An aluminum surface as in claim 11, 14 or 17 wherein the coating solution employed to coat the surface contains from about 0.5×10 -3 moles/liter to about 1.75×10 -3 moles/liter of zirconium and from about 0.3×10 -3 moles/liter to about 1.75×10 -3 moles/liter of polyhydroxy compound.

Claim 26

An aluminum surface as in claim 24 wherein the coating solution employed to coat the surface has a pH of about 3.0 to about 4.0.

Claim 27

An aluminum surface as in claim 24 wherein nitric acid is present in the coating solution employed to coat the surface.

Claim 28

An aluminum surface as in claim 24 wherein nitric acid is present in the coating solution employed to coat the surface and the solution has a pH of about 3.0 to about 4.0.

Claim 29

A continuous process for coating aluminum surfaces having a bright shiny appearance which comprises contacting such surfaces with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a polyhydroxy compound having no more than 7 carbon atoms, and sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution and provide uncomplexed available fluoride, said solution being free of boron and phosphate, and replenishing said solution as necessary with aqueous replenishing concentrate so as to maintain such concentrations, said replenishing concentrate also being free of boron and phosphate, so as to continuously produce aluminum surfaces having uniformly colorless and clear coatings which are capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resist blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine and glucoheptonate.

Claim 30

A continuous process for coating aluminum surfaces having a bright shiny appearance which comprises contacting such surfaces with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a polyhydroxy compound having no more than 7 carbon atoms, and sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution and provide uncomplexed available fluoride, said solution being free of boron and phosphate, and replenishing said solution as necessary with aqueous replenishing concentrate so as to maintain such concentrations, said replenishing concentrate also being free of boron and phosphate, so as to continuously produce aluminum surfaces having uniformly colorless and clear coatings which are capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resist blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine and glucoheptonate.

Claim 31

A process as in claim 28 wherein zirconium is present in the coating solution employed to coat the surfaces and the temperature of the coating solution is at least about 110° F. to about 160° F.

Claim 32

An aluminum surface as in claim 29 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 33

A process as in claim 28, 29 or 30 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 34

A process as in claim 29 wherein the source of zirconium is ammonium fluozirconate.

Claim 35

A process as in claim 32 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 36

A process as in claim 32 or 33 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 37

A process as in claim 29 wherein the source of zirconium is fluozirconic acid.

Claim 38

A process as in claim 35 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 39

A process as in claim 35 or 36 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 40

A process as in claim 29 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 41

A process as in claim 38 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 42

A process as in claim 38 or 39 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 43

A process as in claim 32 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 44

A process as in claim 41 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 45

A process as in claim 41 or 42 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 46

A process as in claim 35 wherein the polyhydroxy compound is selected from the group consisting of gluconic acid and salts of gluconic acid.

Claim 47

A process as in claim 44 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 48

A process as in claim 44 or 45 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 49

A process as in claim 29, 32 or 35 wherein the coating solution employed to coat the surfaces has a temperature of from about 130° F. to about 150° F. and contains from about 0.5×10 -3 moles/liter to about 1.75×10 -3 moles/liter of zirconium and from about 0.3×10 -3 moles/liter to about 1.75×10 -3 moles/liter of polyhydroxy compound, and the replenishing concentrate consists essentially of from about 30.8×10 -3 moles/liter to about 250.5×10 -3 moles/liter of zirconium, from about 18.9×10 -3 moles/liter to about 148.0×10 -3 moles/liter of polyhydroxy compound, and a material which is a source of about 89.5×10 -3 moles/liter to about 695.0×10 -3 moles/liter of uncomplexed available fluoride.

Claim 50

A process as in claim 47 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 51

A process as in claim 47 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 52

A process as in claim 47 wherein nitric acid is present in the coating solution employed to coat the surfaces and the solution has a pH of about 3.0 to about 4.0.

Claim 53

A process as in claim 38, 41 or 44 wherein the coating solution employed to coat the surfaces has a temperature of from about 130° F. to about 150° F. and contains from about 0.5×10 -3 moles/liter to about 1.75×10 -3 moles/liter of zirconium and from about 0.3×10 -3 moles/liter to about 1.75×10 -3 moles/liter of polyhydroxy compound, and the replenishing concentrate consists essentially of from about 30.8×10 -3 moles/liter to about 250.5×10 -3 moles/liter of zirconium, from about 18.9×10 -3 moles/liter to about 148.0×10 -3 moles/liter of polyhydroxy compound, and a material which is a source of about 89.5×10 -3 moles/liter to about 695.0×10 -3 moles/liter of uncomplexed available fluoride.

Claim 54

A process as in claim 51 wherein the coating solution employed to coat the surfaces has a pH of about 3.0 to about 4.0.

Claim 55

A process as in claim 51 wherein nitric acid is present in the coating solution employed to coat the surfaces.

Claim 56

A process as in claim 51 wherein nitric acid is present in the coating solution employed to coat the surfaces and the solution has a pH of about 3.0 to about 4.0.

Claim 57

A acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for about 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine, and glucoheptonate.

Claim 58

A acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for about 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine, and glucoheptonate.

Claim 59

An aqueous concentrate such that an aqueous coating solution containing about 0.5 to about 10 weight percent of the concentrate has a pH within the range of about 3.0 to about 5.0 and consists essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said coating solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on a aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine, and glucoheptonate.

Claim 60

An aqueous concentrate such that an aqueous coating solution containing about 0.5 to about 10 weight percent of the concentrate has a pH within the range of about 3.0 to about 5.0 and consists essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said coating solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on a aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., wherein said polyhydroxy compound is selected from the group consisting of gluconic acid, a salt of gluconic acid, sorbitol, mannitol, dextrose, ethylene glycol, glycerine, and glucoheptonate.

Claim 61

An aluminum surface having a uniformly colorless and clear coating which is free of boron and phosphate and is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., said coated aluminum surface having been obtained by contacting such aluminum surface with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution.

Claim 62

An aluminum surface having a uniformly colorless and clear coating which is free of boron and phosphate and is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F., said coated aluminum surface having been obtained by contacting such aluminum surface with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution.

Claim 63

A continuous process for coating aluminum surfaces having a bright shiny appearance which comprises contacting such surfaces with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution and provide uncomplexed available fluoride, said solution being free of boron and phosphate, and replenishing said solution as necessary with aqueous replenishing concentrate so as to maintain such concentrations, said replenishing concentrate also being free of boron and phosphate, so as to continuously produce aluminum surfaces having uniformly colorless and clear coatings which are capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resist blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 64

A continuous process for coating aluminum surfaces having a bright shiny appearance which comprises contacting such surfaces with an acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution and provide uncomplexed available fluoride, said solution being free of boron and phosphate, and replenishing said solution as necessary with aqueous replenishing concentrate so as to maintain such concentrations, said replenishing concentrate also being free of boron and phosphate, so as to continuously produce aluminum surfaces having uniformly colorless and clear coatings which are capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resist blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 65

An acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium and hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for about 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 66

An acidic aqueous coating solution having a pH within the range of about 3.0 to about 5.0 and consisting essentially of at least about 0.5×10 -3 moles/liter of zirconium and hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for about 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 67

An aqueous concentrate such that an aqueous coating solution containing about 0.5 to about 10 weight percent of the concentrate has a pH within the range of about 3.0 to about 5.0 and consists essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said coating solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 68

An aqueous concentrate such that an aqueous coating solution containing about 0.5 to about 10 weight percent of the concentrate has a pH within the range of about 3.0 to about 5.0 and consists essentially of at least about 0.5×10 -3 moles/liter of zirconium or hafnium or a mixture thereof, at least about 0.025×10 -3 moles/liter of a water soluble polyhydroxy compound having no more than 7 carbon atoms, and at least sufficient fluoride to combine with and form a soluble complex with all of the zirconium and hafnium present in the solution, said coating solution being free of boron and phosphate and capable of forming a uniformly colorless and clear coating on an aluminum surface which is capable of turning light golden brown to purple in color when heated at a temperature of 900° F. for 5 minutes, but which resists blackening for at least 5 minutes when heated in water having a temperature within the range of about 140° F. to about 170° F.

Claim 69

An aluminum surface as in claim 1 or 57 wherein said coating underlies an overlying water-borne coating.

Claim 70

A process as in claim 28 or 58 including applying to said coating an overlying water-borne coating.

Claim 71

An aluminum surface as in claim 61 wherein said water-borne coating is a polyester coating.

Claim 72

A process as in claim 62 wherein said water-borne coating is a polyester coating.