# US 5,350,791 A · Hydrophilicizing treatment for metal objects

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- Number: US 5,350,791 A
- Document ID: US5350791A
- Status: Granted
- Kind: A
- Application number: 08/062,091
- Filed: 1993-05-14
- Granted: 1994-09-27
- Earliest claimed: 1992-07-02
- Assignees: Henkel Corporation
- Inventors: Chi-Fan Hsu
- Web page: https://patentgrep.com/patent/US5350791A

## CPC

- F28F 19/02: by using coatings, e.g. vitreous or enamel coatings
- C09D 133/02: Homopolymers or copolymers of acids; Metal or ammonium salts thereof
- C23C 22/66: Treatment of aluminium or alloys based thereon
- C23C 22/83: Chemical after-treatment
- C08L 71/02: Polyalkylene oxides
- F28F 2265/20: for preventing development of microorganisms
- Y10S 428/933: Sacrificial component
- Y10T 428/31511: Of epoxy ether
- Y10T 428/31529: Next to metal
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Substantially improved retention of hydrophilicity after exposure to high temperature can be provided on a metal substrate, particularly an aluminum alloy of the type used for heat exchanger fins by an aqueous liquid hydrophilicizing treatment composition containing acrylic and/or methacrylic acid polymer or copolymer, polyether alcohol, and alkali metal silicate. The treatment composition may also contain an anti-microbial agent and additional alkalinizer. The hydrophilicizing treatment is preferably applied over a conventional conversion coating, particularly a chromium phosphate or chromium oxide conversion coating.

## Claims

### Claim 1

A concentrate composition for preparing a hydrophilicizing treatment by dilution with water, said concentrate composition consisting essentially of:
(A) from about 1.0 to about 60% by weight of a component selected from the group of water soluble polymers and copolymers of acrylic and methacrylic acids and salts thereof;
(B) from about 1.1 to about 60% by weight of a component of water soluble polyether molecules conforming to the general formula:
R.sup.1 --(--O--).sub.p --(C.sub.n H.sub.2n O).sub.q --R.sup.2,
where each of R.sup.1 and R.sup.2 independently is H or an alkyl moiety containing not more than 4 carbon atom; p is either 0 or 1; n is an integer from 2 to 4 inclusive, and the value of n may be selected independently for each of the q groups present in the polymer molecule; and q is an integer with a value of at least 2; and
(C) from about 1.0 to about 40% by weight of a component of water soluble alkali metal silicates; and, optionally,
(D) an anti-microbial effective amount of a anti-microbial agent; and, optionally,
(E) up to about 20% by weight of a component of water soluble non-silicate alkalinizing agents; and, optionally.
(F) water.

### Claim 2 (depends on 1)

A composition according to claim 1, wherein the concentration of component (A) is in the range from about 1.0 to about 20% by weight, the concentration of component (B) is in the range from about 1.0 to about 40% by weight, the concentration of component (C) is in the range from about 1.0 to about 30% by weight, and the concentration of component (E) is in the range from about 0.4 to about 14% by weight.

### Claim 3 (depends on 2)

A composition according to claim 2, wherein the concentration of component (A) is in the range from about 1.0 to about 10% by weight, the concentration of component (B) is in the range from about 1.0 to about 20% by weight:, the concentration of component (C) is in the range from about 1.0 to about 20% by weight, and the concentration of component (E) is in the range from about 0.5 to about 10% by weight.

### Claim 4 (depends on 3)

A composition according to claim 3, wherein at least 85% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, methacrylic acid, and mixtures thereof, and component (A) has an average molecular weight in the range from about 500 to about 1.25.times.10.sup.6 ; at least 95% of component (B) consists of molecular blocks which could have been made by polymerizing ethylene oxide, and the average molecular weight of component (B) is in the range from about 76 to about 1.0.times.10.sup.5 ; and at least 84% of component (C) consists of silicates of sodium, potassium, or a mixture thereof in which the atomic ratio between alkali metal and silicon atoms is in the range from about 0.40:1.0 to about 4.0:1.0.

### Claim 5 (depends on 2)

A composition according to claim 2, wherein at least 73% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, methacrylic acid, esters of acrylic and methacrylic acids with alcohols having no more than 4 carbon atoms, and mixtures thereof, and component (A) has an average molecular weight in the range from about 500 to about 6.0.times.10.sup.6 ; at least 53% of component (B) consists of molecular blocks which could have been made by polymerizing ethylene oxide, propylene oxide, or a mixture thereof, and the average molecular weight of component (B) is in the range from about 76 to about 5.0.times.10.sup.5 ; at least 52% of component (C) consists of silicates of sodium, potassium, or a mixture thereof in which the atomic ratio between alkali metal and silicon atoms is in the range from about 0.35:1.0 to about 5.0:1.0; and component (E) is selected from the group consisting of alkali metal hydroxides, phosphates, and mixtures thereof.

### Claim 6 (depends on 1)

A composition according to claim 1, wherein at least 73% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, methacrylic acid, esters of acrylic and methacrylic acids with alcohols having no more than 4 carbon atoms, and mixtures thereof, and component (A) has an average molecular weight in the range from about 500 to about 6.0.times.10.sup.6 ; at least 53% of component (B) consists of molecular blocks which could have been made by polymerizing a mixture of molecules selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and mixtures thereof, and the average molecular weight of component (B) is in the range from about 76 to about 6.0.times.10.sup.6 ; and at least 52% of component (C) consists of silicates of sodium, potassium, or a mixture thereof in which the atomic ratio between alkali metal and silicon atoms is in the range from about 0.35:1.0 to about 5.0:1.0.

### Claim 7

A process of hydrophilicizing a metal surface, said surface optionally bearing a pre-existing conversion coating, said process comprising contacting the metal surface for a time within the range from about 5 to about 600 seconds at a temperature within the range from about 10.degree. to about 90.degree. C. with a hydrophilicizing composition consisting essentially of water and:
(A) from about 1 to about 300 g/L, measured as dissolved solids, of a component selected from the group of water soluble polymers and copolymers of acrylic and methacrylic acids and salts thereof;
(B) from about 1 to about 300 g/L of a component of water soluble polyether molecules conforming to the general formula:
R.sup.1 --(--O--).sub.p --(C.sub.n H.sub.2n O).sub.q --R.sup.2,
where each of R.sup.1 and R.sup.2 independently is H or an alkyl moiety containing not more than 4, preferably not more than 3, more preferably not more than 2, or most preferably only 1, carbon atom; p is either 0 or 1; n is an integer from 2 to 4 inclusive, preferably 2 or 3, most preferably 2, and the value of n may be selected independently for each of the q groups present in the polymer molecule; and q is an integer with a value of at least 2; and
(C) from about 5 to about 200, g/L of a component of water soluble alkali metal silicates; and, optionally,
(D) an anti-microbial effective amount of a anti-microbial agent; and, optionally,
(E) from about 2 to about 100 g/L of a component of water soluble non-silicate alkalinizing agents.

### Claim 8 (depends on 7)

A process according to claim 7, wherein, in the hydrophilicizing composition, the concentration of component (A) is in the range from about 1 to about 50 g/L, the concentration of component (B) is in the range from about 2 to about 200 g/L, the concentration of component (C) is in the range from about 5 to about 150 g/L

### Claim 9 (depends on 8)

A process according to claim 8, wherein, in the hydrophilicizing composition, the concentration of component (A) is in the range from about 1 to about 50 g/L, the concentration of component (B) is in the range from about 2 to about 100 g/L, the concentration of component (C) is in the range from about 5 to about 100 g/L.

### Claim 10 (depends on 9)

A process according to claim 9, wherein, in the hydrophilicizing composition, the concentration of component (A) is in the range from about 2 to about 10 g/L, the concentration of component (B) is in the range from about 10 to about 30 g/L, the concentration of component (C) is in the range from about 15 to about 60 g/L, and the pH is in the range from about 10.0 to about 13.0.

### Claim 11 (depends on 10)

A process according to claim 10, wherein at least 73% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, methacrylic acid, esters of acrylic and methacrylic acids with alcohols having no more than 4 carbon atoms, and mixtures thereof, and component (A) has an average molecular weight in the range from about 500 to about 6.0.times.10.sup.6 ; at least 53% of component (B) consists of molecular blocks which could have been made by a mixture of molecules selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and mixtures thereof; at least 52% of component (C) consists of silicates of sodium, potassium, or a mixture thereof in which the atomic ratio between alkali metal and silicon atoms is in the range from about 0.35:1.0 to about 5.0:1.0; and component (E) is selected from the group consisting of alkali metal hydroxides, phosphates, and mixtures thereof.

### Claim 12 (depends on 11)

A process according to claim 11, wherein at least 85% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, methacrylic acid, and mixtures thereof, and component (A) has an average molecular weight in the range from about 500 to about 1.25.times.10.sup.6 ; at least 85% of component (B) consists of molecular blocks which could have been made by polymerizing ethylene oxide, propylene oxide, or a mixture thereof, and the average molecular weight of component (B) is in the range from about 76 to about 1.0.times.10.sup.5 ; at least 84% of component (C) consists of silicates of sodium, potassium, or a mixture thereof in which the atomic ratio between alkali metal and silicon atoms is in the range from about 0.40:1.0 to about 4.0:1.0; and the pH is in the range from about 9.0 to about 14.0.

### Claim 13 (depends on 12)

A process according to claim 12, wherein at least 96% of component (A) consists of residues from polymerizing monomers selected from the group consisting of acrylic acid, salts thereof, and mixtures thereof, and component (A) has an average molecular weight in the range from about 1000 to about 5.0.times.10.sup.5 ; at least 96% of component (B) consists of molecular blocks which could have been made by polymerizing ethylene oxide, and the average molecular weight of component (B) is in the range from about 150 to about 2000; at least 96% of component (C) consists of silicates of potassium in which the atomic ratio between potassium and silicon atoms is in the range from about 0.40:1.0 to about 1.0:1.0; and component (E) is selected from the group consisting of sodium and potassium hydroxides and phosphates and mixtures thereof.

### Claim 14 (depends on 13)

A process according to claim 13, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.1 to 1.5 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 15.degree. to about 60.degree. C.; the time of contact is within the range from about 10 to about 300 seconds; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250.degree. C.

### Claim 15 (depends on 12)

A process according to claim 12, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.1 to about 1.5 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 15.degree. to about 60 .degree. C.; the time of contact is within the range from about 10 sec to about 10 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250 .degree. C.

### Claim 16 (depends on 11)

A process according to claim 11, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.1 to about 2.0 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 12.degree. to about 75.degree. C.; the time of contact is within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250 .degree. C.

### Claim 17 (depends on 10)

A process according to claim 10, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.1 to about 2.0 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 15.degree. to about 60.degree. C.; the time of contact is within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250 .degree. C.

### Claim 18 (depends on 9)

A process according to claim 9, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.1 to about 2.0 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 12.degree. to about 75.degree. C.; the time of contact is within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250.degree. C.

### Claim 19 (depends on 8)

A process according to claim 8, wherein the surface treated is an aluminum or aluminum alloy surface precoated with a chromium oxide or chromium phosphate conversion coating; the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.05 to about 3.0 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 12.degree. to about 75.degree. C.; the time of contact is within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250.degree. C.

### Claim 20 (depends on 7)

A process according to claim 7, wherein the mass added to the surface treated by the hydrophilicizing treatment is within the range from about 0.05 to about 3.0 g/m.sup.2 of surface treated; the temperature during contact between the hydrophilicizing composition and the metal is within the range from about 12.degree. to about 75.degree. C.; the time of contact is within the range from about 5 sec to about 30 min; and the wet surface coated with the hydrophilicizing composition is dried in an oven at a temperature within the range from about 50.degree. to about 250.degree. C.