JPH1161433A - Aluminum coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production of an aluminum coating material in which the close adhesion between a substrate-coating type chromate film and a hydrophilic film formed thereon is improved so as to prevent the hydrophilic film from peeling from the substrate coating type chromate film in the aluminum coating material. SOLUTION: An aluminum plate is treated with a surfactant or an alkaline chemical containing the surfactant and a chelating agent, and rinsed in water, and the organic matter containing the surfactant, the chelating agent and a non-defatted rolling oil on the surface of the aluminum plate is heated and dried at 100 to 300 deg.C in an inert gas state or at 100 to 200 deg.C in the atmosphere so that the organic matter is <=4 mg/m<2> in density, and then is cooled, and further, is applied with the coating type chromate solution, and heat-dried and cooled and hydrophilic film is formed on the coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for an aluminum fin material for a heat exchanger used for a room air conditioner, a car air conditioner, and the like.

[0002]

2. Description of the Related Art In an aluminum fin material for a heat exchanger (hereinafter simply referred to as an aluminum fin material), a corrosion-resistant film layer is formed and a hydrophilic film layer is formed on the layer. Conventionally, there have been many proposals for improving the adhesion between aluminum and a chromate film. However, even if the corrosion resistance is improved, the adhesion between the chromate layer and the treated layer of the hydrophilic resin layer (peeling resistance There has been little consideration for improving), and this is a blind spot, and this solution has been required.

For example, a chromate film obtained by a chemical conversion treatment is heated to 20 to 200 ° C. to form fine cracks in the chromate layer, thereby improving the adhesion to the hydrophilic resin layer (JP-A-3-93539). issue). After hot rolling and before coating, acid or p
Etching is carried out with an alkaline solution of H10 or more at 50 mg / m ² or more to remove an oxide film on the aluminum surface, followed by chemical conversion treatment (JP-A-4-32583). After degreasing, or in place of degreasing, wash with an alkaline solution having a pH of 10 or more for 1 to 300 seconds, rolling oil on aluminum surface, abrasion powder generated during rolling, leveler lubricating oil,
After removing the oxide film, a chemical conversion treatment is performed. However, these methods have insufficient adhesion between the chromate film and the hydrophilic film of the obtained aluminum fin material. Especially in the case of coating type chromate, sufficient adhesion is not obtained, when winding a coil of aluminum coating material, when forming an aluminum plate material into a fin material by pressing, etc., when assembling the fin material to a heat exchanger, etc. There is a drawback that the hydrophilic coating layer is easily peeled off when hard objects such as metal come into contact with each other or between the painted surfaces due to insufficient adhesion between the painted surfaces.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an aluminum coating material, which is one of the major troubles during the manufacturing process of the fin material of the aluminum plate and the assembling process of the heat exchanger or the operation of the heat exchanger. An object of the present invention is to establish a method of manufacturing an aluminum coating material with improved adhesion between a mold chromate film and a hydrophilic film provided thereon to prevent the peeling of the film.

[0005]

According to the present invention, (1) an aluminum plate is treated with a surfactant or an alkaline agent containing a surfactant and a chelating agent, washed with water, and then washed with water.
0 ° C to 300 ° C in an inert gas atmosphere or 100 ° C to
In an atmosphere at 200 ° C., an organic substance containing a surfactant, a chelating agent, and a non-degreased rolling oil on the surface of the aluminum plate is heated and dried until it becomes 4 mg / m ² or less, and then cooled,
A method for producing an aluminum coating material in which a coating type chromate solution is applied, and the resulting solution is heated, dried and cooled, and then a hydrophilic film is formed on the coating film. (2) The aluminum plate material is treated with a surfactant or a surfactant and a chelating agent. Treating with an alkaline chemical containing, washing with water, and then rolling the surfactant, chelating agent and undegreased on the aluminum plate surface in an inert gas atmosphere at 100 ° C. to 300 ° C. or in an atmosphere at 100 ° C. to 200 ° C. The organic substance containing oil is heated and dried until it becomes 4 mg / m ² or less, then cooled, a coating type chromate solution is applied, and 4 mg of the organic substance adhered on the coating type chromate film.
/ M ² or less, and after cooling, further provide a hydrophilic film on the coating film, (1) the method for producing an aluminum coating material according to (1), (3) the pH of the alkaline agent is 9 or more. Water temperature when washing with water is from room temperature to 90
° C, the coating amount of the coating type chromate is 3 to 200 mg / m ² as the coating amount of chromium, and the heating and drying temperature is 40 to 30.
(4) The method for producing an aluminum coating material according to (1) or (2), wherein the hydrophilic coating is a hydrophilic resin coating at a temperature of 0 ° C., wherein the coating amount is 0.1 to 5 g / m ² , and heating is performed. (1) The method for producing an aluminum coating material according to any one of (1) to (3), wherein the drying temperature is 140 to 300 ° C. and the heating and drying time is 5 to 60 seconds, and (5) the hydrophilic film is water glass or colloidal silica. In the case of a system paint, any of (1) to (3) in which the coating amount of silicon is 20 to 400 mg / m ^{2 in} silicon amount, the heating and drying temperature is 140 to 300 ° C., and the heating and drying time is 5 to 60 seconds. The above object has been achieved by developing the method for producing an aluminum coating material described above.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, aluminum means pure aluminum for industrial use and aluminum alloy (hereinafter, both are simply referred to as aluminum), and in particular, JIS 105 used for fin materials of heat exchangers.
0, 1100, 1200, etc., and a material obtained by adding 0.2 to 0.4% of manganese to pure aluminum. The aluminum plate refers to a rolled plate having a thickness of 50 to 2000 μm (in the present invention, the plate refers to both a plate cut and a coil wound). Degreasing, washing with water,
An aluminum coating material is obtained by heat drying, cooling, chromate coating, heat drying, and hydrophilic film coating.

[0007] The surfactant of the alkaline agent used in the aluminum coating material of the present invention is HL to remove oil on the aluminum plate and to enhance its dispersibility.
Nonionic surfactants having a B (hydrophilic lipophilic balance) of about 11 to 15 such as polyoxyethylene alkyl ethers and polyoxyethylene alkyl phenyl ethers; anionic surfactants such as higher alcohol sulfates and higher fatty acid alkali salts; One or two or more of these may be used. In combination therewith, a chelating agent such as ethylenediaminetetraacetic acid disodium salt and sodium gluconate may be used to enhance the etching properties of the aluminum plate.

A surfactant or an alkaline drug containing the surfactant and a chelating agent may be used as an alkali builder such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, phosphoric acid 3
Sodium, 3 potassium phosphate, 2 sodium hydrogen phosphate, sodium dihydrogen phosphate, 2 potassium hydrogen phosphate,
It contains one or more alkali compounds such as potassium dihydrogen phosphate, sodium orthosilicate, potassium orthosilicate, sodium silicate, potassium silicate and the like. When the aluminum plate is degreased with the alkaline agent, an aqueous solution having a pH of 9 or more, preferably 10 or more is used. If the pH of the alkaline agent is less than 9, removal of an oxide film or the like generated in the annealing step or the like becomes insufficient, and the adhesion to the coating type chromate is hindered. At the time of washing, the temperature of the alkaline chemical is set to 40 to 90 ° C, preferably 50 to 80 ° C. If the temperature is lower than 40 ° C., an oxide film formed in the annealing step or the like remains, which impairs the adhesion to the coating type chromate. At the time of treatment, the alkaline chemical is sprayed onto an aluminum plate material for 1 to 20 seconds, preferably 3 to 10 seconds, and oils such as rolling oil on the surface, foreign substances such as metal powder, and rolling, annealing steps, etc. The oxide film generated in step is removed.

[0009] The aluminum plate material washed with the alkaline chemical is spray-washed with water (pure water, soft water, industrial water) at room temperature to 90 ° C, preferably 40 to 80 ° C. The water washing is performed by spraying using 2 to 50 liters, preferably 4 to 30 liters of water per 1 m ² of the surface area of the aluminum plate. The higher the spray pressure, the smaller the amount of water to be supplied to the aluminum plate material. However, the above-mentioned amount of water is required at the water pressure normally used in a coating line. Also, as the amount of washing water increases, the amount of the surfactant and the chelating agent on the surface of the aluminum plate decreases, but the amount of washing water is 1 m ^2.
In order to secure a water supply amount exceeding 50 liters per unit, a large-scale apparatus is required, so that it is practically difficult.

The alkali components (eg, sodium hydroxide, potassium hydroxide, sodium carbonate, etc.) and the acid components (chlorine ions, sulfate ions, phosphate ions, etc.) on the aluminum plate material themselves form a chromate film and a hydrophilic film. Does not hinder adhesion. Therefore, the water quality of the washing water does not need to be pure water in principle as long as the content of the surfactant or the chelating agent is low, and soft water and industrial water can be used. However, tap water is injected with chlorine for sterilization, and itself contains a large amount of chlorine ions, so if it remains on the aluminum plate after washing,
If possible, it is preferable to use deionized water or not to use tap water, since corrosion of the aluminum coating material is caused.

After washing with water as described above, the temperature is 100 ° C. to 300 ° C., preferably 150 ° C. to 25 ° C. in an inert gas atmosphere.
Drying by heating at a temperature of 0 ° C, and 100 ° C to 200 ° C, preferably 150 ° C to 200 ° C in air to avoid oxidation.
The drying is carried out at a temperature of ° C. so that the total amount of organic substances such as a surfactant, a chelating agent, and undegreased residual rolling oil on the surface of the aluminum plate material is 4 mg / m ² or less. This amount is 4
When the amount exceeds mg / m ² , the adhesion between the coating type chromate film of the aluminum coating material and the hydrophilic film applied thereon is greatly impaired. The inert gas atmosphere is preferably an argon atmosphere, but may be a nitrogen gas atmosphere. Heat drying in air tends to form an oxide film on the surface of the aluminum plate, and this oxide film hinders the reaction between the coating type chromate and the surface of the aluminum plate and reduces the adhesion. In (2), the effect is small, so that heating and drying at that temperature is possible. The heating and drying temperature is preferably a temperature at which the evaporation of the surfactant and the chelating agent on the aluminum plate is promoted, and does not necessarily need to be a temperature higher than the boiling point of the compound. At a temperature lower than 100 ° C., the evaporation rate of the surfactant and the chelating agent is small, and the effect is small. A temperature exceeding 300 ° C. greatly promotes the evaporation rate of these compounds, but is unsuitable because it greatly accelerates the annealing speed of the material or the formation rate of an oxide film. In this case, the content of organic substances in the atmosphere gas in the heating and drying furnace is preferably 5% or less, and more preferably 1% or less in terms of carbon. If it exceeds 5%, the amount of organic substances adsorbed on the surface of the aluminum plate increases, and the adhesion between the coating type chromate film and the hydrophilic film decreases.

[0012] The coating type chromate used in the present invention is a usual chromate coating agent, which is a phosphate ion,
It contains hexavalent chromium ion and / or trivalent chromium ion, fluorine ion, alkali metal ion such as sodium or potassium, etc., and may also contain silicate ion, zirconium compound, titanium compound, etc.
Further, it may contain an acrylic resin such as polyacrylic acid, polyacrylate or polyacrylamide, but preferably does not contain a surfactant and / or a chelating agent.

A liquid containing such a coating type chromate is applied to an aluminum plate material by a roll coater or a sprayer, and is applied at 40 ° C. to 300 ° C., preferably 150 ° C.
Several seconds to several minutes, preferably 10 seconds to 30 minutes in the range of 250 ° C.
Heat and dry for about 2 seconds, chromate film layer 3 ~ 200m
g / m ² . If the heating and drying temperature is lower than 40 ° C., sufficient adhesion between the coating type chromate and aluminum cannot be obtained. At a temperature exceeding 300 ° C., the material softens. In addition, the amount of chromate applied is 3 mg /
If it is less than ² m2, sufficient corrosion resistance cannot be imparted.
Even if applied in an amount exceeding g / m ² , there is no improvement in the corrosion resistance, and the cost is simply increased, resulting in waste. In this case, 4 mg / m ^{2 of} an organic substance adheres on the coating type chromate film.
It is a more preferred embodiment to heat and dry as follows. Specifically, low-boiling organic substances are used for various chemicals used in the previous process, and heating is performed to a temperature equal to or higher than the boiling point, a furnace gas containing organic substances is passed through an oxidation catalyst layer supporting platinum, and a drying furnace is used. The purpose is to keep the atmosphere as small as possible by completely burning the concentration of organic substances in the drying furnace, for example, by increasing the amount of fresh air.

The aluminum plate having the coating type chromate film thus obtained is then provided with a hydrophilic film. The hydrophilic film is not particularly limited as long as the coating substrate has a hydrophilic property, but examples of the organic polymer type include polyvinyl alcohol, cellulose resins such as carboxymethyl cellulose, acrylamide, acrylic acid, and acrylic acid. An acrylic resin mainly composed of an ester or the like is suitable, and a homopolymer thereof, a mixture of two or more thereof, or a copolymer thereof may be used. These base resins may be of a self-crosslinking type, if necessary, hexabutylol melamine, a melamine compound such as hexabutyrol methyl melamine, a compound having an epoxy group, urea to which a butylol group is added, or A curing agent such as a compound having an isocyanate group may be added.

As the base material of the inorganic hydrophilic film,
An inorganic paint mainly composed of water glass or colloidal silica may be used (a paint mixed with a resin such as an acrylic resin or polyvinyl alcohol may be used), and a metal crosslinking agent such as zirconate is added. It may be done.

The hydrophilic film-forming paint includes polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene-added sorbitan fatty acid ester, sucrose fatty acid ester, and polyoxyethylene polyoxypropylene block copolymer. Nonionic surfactants such as coalesced polyoxyethylene lanolin alcohol ethers and polyoxyethylene alkylamine ethers; and anionic surfactants such as dialkyl sulfosuccinates, alkyl sulfonates, alkyl phosphates and polyoxyethylene alkyl phosphates It may contain a surfactant and a cationic surfactant such as alkyltrimethylammonium chloride.

The amount of the hydrophilic film to be applied, the heating and drying temperature, and the heating and drying time cannot be specified by the conditions of use of the aluminum coating material, the characteristics of the hydrophilic film forming paint, the characteristics of the heating and drying furnace, and the like. Has a coating amount of 0.
1 to 5 g / m ^2, preferably from 0.2 to 1.5 g / m ^2,
The heating and drying temperature is 140 ° C. to 300 in the case of the thermosetting type
℃, preferably 150 ℃ ~ 250 ℃, the heating and drying time is 5
６０60 seconds, preferably 10-30 seconds. If the coating amount is less than 0.1 g / m ² , the hydrophilicity tends to be insufficient, and if the amount exceeds 5 g / m ² , the hydrophilicity is not improved, and the cost is merely increased, resulting in waste. It is.

In the case of a coating material for forming an inorganic hydrophilic film such as a water glass type or a colloidal silica type, the amount of silica is 20 to 4%.
00 mg / m ² , preferably in the range of 50 to 300 mg / m ² . If it is less than 20 mg / m ² , sufficient hydrophilicity cannot be obtained, and if it exceeds 400 mg / m ² , not only the hydrophilicity is not further improved, but also the precipitated silicon compound becomes powdery, and the adhesion of the coating film decreases. In the case of press molding, problems such as easy peeling occur.

When the coating type chromate film is provided, if there are no organic substances such as a surfactant, a chelating agent, and an undegreased rolling oil residue in the degreasing agent on the aluminum plate material, the coating type chromate film and the hydrophilic film are formed. While having good adhesion, it was found that when this was present, organic substances such as surfactants that had been on the aluminum plate material migrated onto the coating type chromate film and hindered the adhesion with the hydrophilic film. Was.

The mechanism by which an organic substance such as a surfactant on an aluminum plate migrates onto the coating-type chromate is unknown, but even if the coating-type chromate coating layer is thickened, the coating-type chromate solution cannot be removed. The presence of an organic substance such as a surfactant on the surface of the aluminum plate material before coating decreases the adhesion between the coating type chromate film and the hydrophilic resin film, and in this case also, the corrosion resistance of the coating type chromate is reduced. Since the chromate film is porous, it is difficult to imagine a mechanism in which an organic substance such as a surfactant on the surface of the aluminum plate material passes through the coatable chromate film and floats on the surface of the coatable chromate since the chromate film is porous. It is assumed that, when the coating type chromate is applied, an organic substance such as a surfactant on the aluminum plate material dissolves in the coating type chromate and floats on the surface when baked.

Coating type The total amount of organic substances such as surfactants on the surface of the aluminum plate before the application of chromate is 4 mg /
When it is less than m ² , the adhesion between the chromate film and the hydrophilic film is not hindered. At the laboratory level, it is possible to maintain such a level only by washing with water, but industrially, the amount of surfactant, chelating agent, undegreased residual rolling oil, etc. on the aluminum sheet surface is extremely required by the present invention. It is difficult and practically impossible to keep the value low because the amount of drainage is greatly increased and a long multi-stage treatment is required. Therefore, it is difficult to achieve 4 mg / m ² or less only by washing with water.

However, when the aluminum plate after washing with water is heated and dried, low-molecular-weight organic substances such as a surfactant and a chelating agent on the aluminum plate evaporate at a high rate, so that the organic substances on the aluminum plate are greatly reduced. , This value is 4m on the surface of aluminum plate
When heated and dried to a g / m ² or less, the adhesion between the coating type chromate film and the hydrophilic film is greatly improved. However, in the heating and drying of the aluminum plate after washing with water, setting an atmosphere and temperature (in an atmosphere of an inert gas at 100 to 300 ° C. or an atmosphere of 100 to 200 ° C. more severe) that promotes the growth of an oxide film is set. In addition, the formation of the coating type chromate film itself is disturbed, and peeling or poor corrosion resistance occurs at the interface between the surface of the aluminum plate and the coating type chromate film. Therefore, when the heating and drying are performed in an inert gas or in air, it is necessary to perform the drying under conditions that do not promote formation of an oxide film.

When baking the coating type chromate film provided as described above, organic substances in the atmosphere in the heating and drying furnace are adsorbed on the surface of the coating type chromate film. Such an adsorption layer, like organic substances such as a surfactant, a chelating agent, and a non-degreased rolling oil, inhibits the adhesion between the coating type chromate film and the hydrophilic film. Details of the adsorbed substance are unknown, but resins such as acrylic resin, which is one of the coating-type chromate liquid components, and when baking other paints in the same furnace, the resins and solvents contained in the paints and their thermal polymerization Stuff,
Pyrolysates or mixtures thereof are conceivable. These adsorbed substances seem to be physically adsorbed on the coating type chromate when the heating and drying temperature is low, and are chemically adsorbed when the heating and drying temperature is high. It is difficult to remove these adsorbed substances, especially the adsorbed substances chemically adsorbed, even by performing solvent washing or water washing after heating and drying the coating type chromate,
Even if such a cleaning treatment is performed, the adhesion between the coating type chromate film and the hydrophilic film cannot be significantly improved.
Therefore, it is preferable to control the heat-drying atmosphere and the heat-drying temperature of the coating type chromate to minimize the adsorption to the coating type chromate film. The adsorption of organic substances such as a surfactant, a chelating agent, and a residue of undegreased rolling oil in an alkaline chemical onto the coating type chromate film is controlled, and the organic substance on the coating type chromate film is 4 mg / m ^2.
When it is less than the above, the adhesion of the hydrophilic film is further improved.

[0024]

【Example】

(Example 1) An aluminum plate material (11
00-H24) with an alkaline degreasing agent containing a surfactant (Surf Cleaner 33, manufactured by Nippon Paint Co., Ltd.)
Using a 1% aqueous solution of 0), spray-degreased (spray pressure = 2 kgf / cm ² , spray time = 10 seconds) at 60 ° C. The aluminum plate was immediately spray-washed and degreased with 60 ° C. hot water (soft water, spray pressure = 2 kgf / cm ² ) while changing the spray time and hot water washing amount to 1 to 45 liter / m ² . Then, the aluminum plate was immediately dried in a heating and drying oven under the conditions shown in Table 1 for 5 seconds. In this case, the amount of organic substances in the furnace gas atmosphere was 0.5%. For the measurement of organic substances, the surface of the dried aluminum plate material was washed with carbon tetrachloride, and the amount of organic substances was measured from the absorption depth of the IR spectrum of the organic substances eluted in carbon tetrachloride. The aluminum plate material used as the aluminum coating material was subjected to a coating type chromate coating and heat drying without performing the carbon tetrachloride extraction work, and then a hydrophilic paint was coated and heated and dried. In this case, a coating type chromate solution (Nippon Paint Co., Ltd .: trade name Surfalcoat 427) was used for coating, and the amount of chromium adhering was 20 mg /
It was adjusted to m ^2. The heating and drying were performed in an argon atmosphere at an ultimate temperature of 150 ° C. and a heating and drying time of 30 seconds. The organic matter content in the furnace atmosphere was 0.1%.

As the hydrophilic film, a water glass type paint (Nippon Paint Co., Ltd., trade name: Surfalcoat 131) was used. The coating amount was 100 mg / m ^{2 in} silicon. The surface of the aluminum coated plate obtained as described above was rubbed with a Kimwipe, and the number of times immediately before the peeling of the hydrophilic film was measured.

[0026]

[Table 1]

(Example 2) A 1% aqueous solution of an aluminum material (1100-H24) having a thickness of 0.1 mm and an alkaline degreasing agent (Surf Cleaner 330, manufactured by Nippon Paint Co., Ltd.) containing a surfactant was used. Spray at 60 ° C using
Degreasing (spray pressure = 2 kgf / cm ² , spray time =
10 seconds). Immediately wash this aluminum plate with hot water (industrial water, spray pressure = 2 kgf / cm ² , spray time = 10 seconds, water temperature = 70 ° C., hot water washing amount = 15 liter / m)
² ) to obtain a degreased aluminum plate. This material was immediately dried in a heating drying oven at 150 ° C. for 5 seconds in air containing an organic substance in an amount shown in Table 2 in an atmosphere in the furnace. Next, a coating type chromate solution (Nippon Paint Co., Ltd.)
Co., Ltd .: Surfalcoat 427) (trade name), and coating and heat drying were performed so that the amount of chromium adhered was 20 mg / m ² . The heating and drying of the coating type chromate solution is carried out in an argon atmosphere at an ultimate temperature of 120 to 320 ° C. and a heating and drying time of 30.
Seconds. The organic matter content in the furnace gas atmosphere was 0.1%. The surface of this aluminum plate material was washed with a carbon tetrachloride solution, and the amount of the organic substance was measured from the absorption depth of the IR spectrum of the organic substance in the carbon tetrachloride. The aluminum plate material used as the aluminum coating material was subjected to hydrophilic paint coating and heat drying without performing carbon tetrachloride extraction work. As the hydrophilic resin film, an organic paint (Nippon Paint Co., Ltd., trade name: Surfalcoat 240) was used. Application amount is 1 g / m as resin amount
^{And 2} . The surface of the aluminum coated plate obtained as described above was rubbed with a Kimwipe, and the number of times immediately before the peeling of the hydrophilic resin film was recorded. Evaluation ：: No peeling even if rubbed 30 times or more ：: Peeled 20 times or more and 29 times or less. C: peeled 10 times or more and 19 times or less. X: Peeled off 9 times or less.

[0028]

[Table 2]

Example 3 A 2% aqueous solution of an aluminum plate material (1100-H24) having a thickness of 0.1 mm and an alkaline degreasing agent (manufactured by Nippon Parkerizing Co., Ltd., trade name: Fine Cleaner 4498) containing a surfactant was used. Using 5
Spray-degrease at 0 ° C (spray pressure = 2 kgf / cm ² ,
(Spray time = 10 seconds). Immediately spray-wash this aluminum plate (industrial water, spray pressure = 2 kgf)
/ Cm ² , spray time 10 seconds, water temperature = 70 ° C., hot water washing amount = 151 / m ² ) to obtain a degreased aluminum plate.
The plate was immediately dried in a heating oven at 150 ° C. for 5 seconds in air. The amount of organic substances in the furnace atmosphere is 0.1
%Met. It was prepared using a coating type chromate solution (trade name: TD116, manufactured by Nippon Parkerizing Co., Ltd.) so that the amount of chromium attached was 30 mg / m ² . Heat drying is performed in an argon atmosphere, attained temperature = 200 ° C., and heat drying time =
2 to 800 seconds. The organic matter content in the furnace gas atmosphere was 0.5%. The surface of this aluminum plate material was washed with a carbon tetrachloride solution, and the amount of the organic substance was measured from the absorption depth of the IR spectrum of the organic substance in the carbon tetrachloride. The aluminum plate material used as the aluminum coating material was subjected to hydrophilic paint coating and heat drying without performing carbon tetrachloride extraction work. As the hydrophilic film, a water glass-based paint (Nippon Paint Co., Ltd., trade name: Surfalcoat 131) was used. The coating amount was 100 g / m ² in terms of silicon. The surface of the aluminum coated plate obtained as described above was rubbed with a Kimwipe, and the number of times immediately before the peeling of the hydrophilic film was recorded. Evaluation ◎: No peeling even when rubbed 20 times or more ：: Peeled 10 times or more and 19 times or less. Δ: peeled 5 times or more and 9 times or less. X: Peeled off 4 times or less.

[0030]

[Table 3]

[0031]

As described above, the adhesion between the coating type chromate film and the hydrophilic film is improved by reducing the amount of the organic substance on aluminum before the coating type chromate coating to 4 mg / m ² or less. When the amount of the organic substance on the chromate film is 4 mg / m ² or less, the adhesion is further improved. The hydrophilic precoated fin according to the present invention can be suitably used as a heat exchanger fin material.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Sudo Alkacentral Building 20F Sky Aluminum Co., Ltd. 1-2-1, Kinshi, Sumida-ku, Tokyo (72) Inventor Nobuyoshi Sasaki 1-2-2 Kinshi, Sumida-ku, Tokyo No. 1 Alca Central Building 20F Sky Aluminum Co., Ltd.

Claims (5)

[Claims] An aluminum plate material is treated with a surfactant or an alkaline agent containing a surfactant and a chelating agent,
After washing with water and then in an inert gas atmosphere at 100 ° C. to 300 ° C. or in an atmosphere at 100 ° C. to 200 ° C., 4 mg /% of an organic substance containing a surfactant, a chelating agent and a non-degreased rolling oil on the surface of the aluminum plate is added. after heating dried to m ² or less, cooling, applying a coating type chromate bath, producing aluminum coating material and providing a hydrophilic film on the coating film after it has been dried by heating and cooling Method. 2. An aluminum plate material is treated with a surfactant or an alkaline agent containing a surfactant and a chelating agent,
After washing with water and then in an inert gas atmosphere at 100 ° C. to 300 ° C. or in an atmosphere at 100 ° C. to 200 ° C., 4 mg /% of an organic substance containing a surfactant, a chelating agent and a non-degreased rolling oil on the surface of the aluminum plate is added. after heating dried to m ² or less, cooling, applying a coating type chromate solution, the adhesion organic material on the coating-type chromate film was heated and dried so that 4 mg / m ^2, was further cooled The method for producing an aluminum coating material according to claim 1, wherein a hydrophilic film is provided on the coating film. 3. The pH of the alkaline agent is 9 or more, the water temperature when washing with water is from room temperature to 90 ° C., and the coating amount of the coating type chromate is 3 to 20 as a chromium coating amount.
The method for producing an aluminum coating material according to claim 1 or ² , wherein the heating and drying temperature is 0 to 300 ° C. 4. When the hydrophilic film is a hydrophilic resin film, the coating amount is 0.1 to 5 g / m ² , the heating and drying temperature is 140 to 300 ° C., and the heating and drying time is 5 to 60 seconds. The method for producing an aluminum coating material according to any one of claims 1 to 3. 5. When the hydrophilic film is a water glass-based or colloidal silica-based coating, the coating amount of the film is 20 to 400 mg / m ² in silicon, and the heating and drying temperature is 140 to 300.
The method for producing an aluminum coating material according to any one of claims 1 to 3, wherein the heating and drying time is 5 to 60 seconds.