JP2002249886A - Treatment method for aluminum or aluminum alloy material, and aluminum or aluminum alloy base material subjected to the treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method for an aluminum or an aluminum alloy material by which corrosion resistance equal to or above that of chromate treatment can be imparted thereto by using a treatment solution which does not contain chromium, its adhesion to a coating film can be improved, and the brightness of aluminum can sufficiently be maintained, and to provide the aluminum or the aluminum alloy material treated by the treatment method and has metallic luster on the surface. SOLUTION: The treatment method for an aluminum or an aluminum alloy material contains a stage (1) where an aluminum material or an aluminum alloy material is treated with acidic aqueous solution of pH 0.6 to 2.0 containing ferric ions of 0.1 to 0.4 g/L and sulfuric ions; a stage (2) where the base material is treated with an acidic chemical conversion treatment agent of pH 1.5 to 4.0 containing zirconium ions or titanium ions of 0.01 to 0.125 g/L, phosphoric ions of 0.01 to 1.0 g/L and fluorine ions of 0.01 to 0.5 g/L; a stage (3) where the base material is treated with a solution containing an epoxy resin; and a stage (4) where the base material is coated with powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating an aluminum substrate or an aluminum alloy substrate, and an aluminum substrate or an aluminum alloy substrate treated by the above-mentioned treatment method.

[0002]

2. Description of the Related Art Aluminum base materials and aluminum alloy base materials are brilliant and light in weight, and are being utilized in various fields by utilizing these characteristics. For example, although iron wheels are mainly used for automobile wheels, demand for aluminum wheels made of an aluminum alloy base material has been increasing since automobiles have been required to have higher quality and lighter weight.

[0003] In general, aluminum substrates have the above-mentioned properties, but have insufficient corrosion resistance. Therefore, if there are scratches or the like on the surface, there is a defect that thread rust is generated or an oxide film is easily formed on the surface. In addition, the aluminum alloy base material has a problem that other components added for increasing the strength float on the surface as impurities, and if it is applied as it is, the adhesion to the coating film may be insufficient. For this reason, these base materials are subjected to a surface treatment in order to improve performance such as corrosion resistance and adhesion.

[0004] As a surface treatment method of an aluminum wheel, after degreasing, anodizing and coloring treatment such as alumite method, etc.
Chromate treatment, chemical film treatment such as MBV method, boehmite method and the like are performed. Among them, a chromate treatment is preferably used because the adhesion and corrosion resistance of the coating film can be further improved.

[0005] In the chromate treatment, however, although excellent corrosion resistance can be imparted, since the chromate film is colored in khaki, the gloss of the surface of the aluminum substrate or aluminum alloy substrate is hidden by the film. I will. For this reason, in applications where the luster of the material is required, such as aluminum wheels, the amount of chromium deposited is limited, and sufficient corrosion resistance may not be provided.

Japanese Patent Application Laid-Open No. 5-179486 discloses the formation of a colorless chromate film on a glittering aluminum wheel which forms a transparent chromate film by subjecting the surface of an aluminum wheel to a cathodic electrolytic treatment using an acidic solution containing chromium ions. A method is disclosed. In this method, since the chromate film is transparent, the light beam penetrates to the surface of the substrate and does not impair the glitter of the material. However, in recent years, the harmfulness of chromium has been pointed out, and it has been desired to perform treatment using a treatment solution containing no chromium.

[0007] At present, non-chromate treatment using a treatment solution containing no chromium is also performed. However, although there is no problem with environmental safety in this treatment method, the corrosion resistance is insufficient as compared with the chromate treatment, so that it is necessary to increase the film thickness in order to impart sufficient corrosion resistance. As a result, the glitter of the material is impaired.

[0008] In particular, in the case of aluminum wheel coating,
Since the sense of quality is regarded as important, it is necessary to utilize not only the corrosion resistance and adhesion but also the glitter of the material, and the above-described processing method cannot sufficiently cope with the problem.

Aluminum substrates and aluminum alloy substrates are also used as aluminum cans for beverages and edible aluminum cans. These surface treatment methods include pickling, degreasing, and chemical conversion treatment. Post-processing is performed as necessary.

As the cleaning agent used in the above pickling treatment,
Japanese Patent Publication No. 3-50838 discloses a surface cleaning agent comprising ferric ion, sulfuric acid and / or nitric acid.
This is a drawing and ironing (D
I) The present invention is applied to an aluminum can for beverages manufactured by processing, and is used for removing a smut composed of lubricating oil and aluminum powder adhered to the aluminum surface during processing.

As a chemical conversion treatment method without performing the above chromate treatment, JP-B-56-33468 discloses zirconium ions or titanium ions, phosphate ions,
A coating agent comprising fluorine ions is disclosed. This is used to improve the corrosion resistance of aluminum cans and the adhesion of coating films.

JP-A-59-219478 discloses a post-treatment agent comprising an organoalkoxysilane compound having a reactive functional group. This is used for improving the corrosion resistance and the adhesion of a coating film on the surface of an aluminum substrate subjected to a chemical conversion treatment with zinc phosphate. All of the above techniques provide a treatment agent containing no chromium, and are preferable in terms of environmental hygiene.However, an aluminum substrate or an aluminum alloy substrate to be applied can be used for beverage aluminum cans, food aluminum cans, and the like. It was used for applications.

Japanese Patent Application Laid-Open No. 2000-28225 discloses a method for pre-painting aluminum wheels which require a material with a brilliancy.
In JP-A No. 1 (1999), after treating an aluminum substrate or an aluminum alloy substrate with an acidic solution containing 0.2 to 0.4 g / L of ferric ion and sulfuric acid and having a pH of 0.6 to 2.0, the zirconium ion or Titanium ion 0.01-0.12
PH containing 5 g / L, phosphate ions 0.01 to 1.0 g / L, and fluorine ions 0.01 to 0.5 g / L
A treatment method comprising a chemical conversion treatment with an acidic chemical conversion treatment agent having a pH of 1.5 to 4.0 and then a treatment with an aqueous solution having a pH of 10 to 12 containing 0.1 to 10 g / L of an organoalkoxysilane is disclosed. However, even in this method, the corrosion resistance and the adhesion of the coating film are somewhat insufficient, and a treatment method having higher corrosion resistance and coating film adhesion has been desired.

[0014]

DISCLOSURE OF THE INVENTION In view of the above, the present invention can provide a corrosion resistance equal to or higher than that of chromate treatment by using a treatment solution containing no chromium, and improve the adhesion to a coating film. And, a method of treating an aluminum substrate or an aluminum alloy substrate capable of sufficiently exhibiting the glitter of aluminum, and an aluminum substrate or an aluminum alloy substrate having a metallic luster on the surface treated by the treatment method. It is intended to provide.

[0015]

According to the present invention, an aluminum substrate or an aluminum alloy substrate is coated with ferric ion of 0.1%.
PH containing 0.4 to 0.4 g / L and sulfate ion.
Step (1) of treating with an acidic aqueous solution of zirconium ion or titanium ion 0.01 to 0.125 g /
L, pH 1.5-containing phosphate ions 0.01-1.0 g / L and fluorine ions 0.01-0.5 g / L
A step (2) of a chemical conversion treatment with an acid conversion treatment agent of 4.0, a step (3) of a treatment with a solution containing an epoxy resin, and
A method for treating an aluminum substrate or an aluminum alloy substrate, comprising a step (4) of powder coating.

The above aluminum substrate or aluminum alloy
A wheel suitable as a gold substrate is a wheel. The above formation
The weight of the film formed by the treatment step (2) is 5
~ 50mg / m ^Two It is preferred that

The present invention also relates to an aluminum substrate or an aluminum alloy substrate which has been treated by the above treatment method. Hereinafter, the present invention will be described in detail.

According to the treatment method of the present invention, a step (1) of treating an aluminum substrate or an aluminum alloy substrate with an acidic aqueous solution, a step (2) of a chemical conversion treatment with an acid chemical treating agent, and a treatment containing an epoxy resin are performed. Step (3), and
It includes a step (4) of powder coating.

As the above aluminum substrate or aluminum alloy substrate (for example, AC-4C or AC-4CH), an aluminum wheel is preferable. The treatment method of the present invention can provide a coating film having excellent corrosion resistance and adhesion, and can maintain the glitter of the surface. Can be.

In the present invention, the aluminum substrate or the aluminum alloy substrate is subjected to a degreasing treatment as required. The degreasing treatment is not particularly limited, and the degreasing treatment can be performed by a method used for ordinary treatment of an aluminum substrate or an aluminum alloy substrate such as alkali degreasing cleaning. The method of the degreasing treatment is not particularly limited, but is preferably performed by a dipping method in order to perform the degreasing effectively. After performing the above degreasing treatment, it is preferable to perform a water washing treatment in order to reduce the amount of the degreasing agent brought into the next step.

In the step (1), the aluminum base material or the aluminum alloy base material is first treated with ferric ion 0.1.
PH 0.6- containing 1-0.4 g / L and sulfate ion
Treated with 2.0 acidic aqueous solution. This step is a pickling step for removing dirt and oxide films on the surface of the aluminum substrate or aluminum alloy substrate.

The ferric ion serves to promote the etching of aluminum by sulfuric acid in the acidic aqueous solution.

The content of the ferric ion is 0.1 to 0.4 g / L in the acidic aqueous solution. If it is less than 0.1 g / L, the effect of accelerating the etching rate is small, and there is a possibility that the etching may be insufficient. Is limited to

The source of the ferric ion is particularly limited.
Not specified, for example, Fe_Two (SO_Four ) _Three , Fe (NO
_Three )_Three , Fe (ClO_Four )_Three And other water-soluble ferric salts such as Fe;
SO_Four , Fe (NO_Three )_Two And other water-soluble ferrous salts, etc.
Can be Above all, providing sulfate ions
Fe that can be_Two (SO_Four )_Three , FeSO_Four Using
Is preferred.

When the above-mentioned water-soluble ferrous salt is used as a source of the above-mentioned ferric ion, an equivalent oxidizing agent is added to an acidic aqueous solution containing the above-mentioned water-soluble ferrous salt, and the necessary amount is added. It is preferable that the ferrous ion is oxidized to ferric ion before use.

The content of the sulfate ion in the acidic aqueous solution is preferably 10.6 to 12.4 g / L. 10.6
If it is less than g / L, the etching of the aluminum surface will be insufficient, and if it exceeds 12.4 g / L, the aluminum surface will be etched improperly.

The source of the sulfate ions is not particularly limited. For example, H ₂ SO ₄ , Fe ₂ (SO ₄ ) ₃ , F
eSO _{4 and the} like.

The acidic aqueous solution has a pH of 0.6 to 2.0. If the pH is less than 0.6, the aluminum surface will be etched unduly.
Since the etching rate of aluminum decreases extremely,
It is limited to the above range. The pH adjustment is preferably performed with H ₂ SO ₄ which is a source of the sulfate ions.

Fluorine ions, surfactants, and the like may be added to the acidic aqueous solution as required.

The pickling is generally carried out at a processing temperature of 30 to 75.
C., preferably 35 to 45.degree. C., and a treatment time of 1 to 5 minutes, preferably about 3 minutes. The pickling method is not particularly limited, and examples thereof include an immersion method and a spray method.

By the above-mentioned pickling, the oxide film on the surface of the aluminum substrate or the aluminum alloy substrate is effectively removed, and impurities other than aluminum contained in the aluminum alloy floating on the surface, for example, Mg , Si, Cu, etc., can be removed. Therefore, the chemical conversion treatment described below can be favorably performed.

The aluminum substrate or aluminum alloy substrate that has been subjected to the pickling treatment in the above step (1) is usually washed with water in order to prevent the acidic aqueous solution from being carried into the subsequent steps. The method of water washing is not particularly limited, and can be performed by a method generally used for metal surface treatment.

In the treatment method of the present invention, after the step (1) of treating the aluminum base material or the aluminum alloy base material with the acidic aqueous solution, in the step (2), the zirconium ion or the titanium ion is used in an amount of 0.01 to 0.01%. 0.
125 g / L, phosphate ion 0.01 to 1.0 g / L,
And a pH containing 0.01 to 0.5 g / L of fluorine ions
The chemical conversion treatment is carried out with an acid conversion treatment agent of 1.5 to 4.0.

The zirconium ion or titanium ion is a film-forming component in the acidic film-forming chemical. The content of the zirconium ion or the titanium ion is 0.01 to
0.125 g / L. When the amount is less than 0.01 g / L, the weight of the formed film becomes insufficient and the performance such as corrosion resistance becomes insufficient. When the amount exceeds 0.125 g / L, the weight of the formed film increases. The thickness is limited to the above range because the film becomes thick and the glitter of the aluminum substrate or the aluminum alloy substrate is impaired.

As a source of the zirconium ion,
There is no particular limitation, for example, fluorozirconate, full
Soluble fluorozirconates such as olosilconate acid;
(NH _Four )_Two ZrF₆ ; Alkali metal fluorozircones
And zirconium fluoride.

The source of the titanium ion is not particularly limited. For example, a soluble fluorotitanate such as fluorotitanate or fluorotitanate acid;
₄ ) ₂ TiF ₆ ; alkali metal fluorotitanate; titanium fluoride and the like.

In the above acidic film chemical conversion treatment agent, the phosphate ions are one of the film forming components and contribute to the corrosion resistance of the formed film and the adhesion to the coating film.

[0038] The content of the phosphate ion is 0.01 to 1.0 g / L in the acid film chemical conversion treatment agent. 0.
When the amount is less than 01 g / L, the weight of the formed film becomes insufficient and the performance such as corrosion resistance becomes insufficient. When the amount exceeds 1.0 g / L, the film becomes too thick, so that it is limited to the above range. .

The source of the phosphate ion is not particularly limited, and examples thereof include a phosphate compound soluble in an acid solution such as phosphoric acid, ammonium phosphate and alkali metal phosphate. As a source of the phosphate ions, orthophosphoric acid is preferably used, but metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, hypophosphoric acid, and salts thereof may be used.

The above-mentioned fluorine ions serve as an etching agent for aluminum in the above-mentioned acidic film chemical conversion treatment agent.

The content of the above-mentioned fluorine ion is 0.01 to 0.5 g / L in the above-mentioned acidic film chemical conversion treatment agent. 0.
When the amount is less than 01 g / L, the etching of the surface of the aluminum substrate or the aluminum alloy substrate becomes insufficient, and the weight of the formed film becomes insufficient. Since the surface of the aluminum alloy base material is unduly etched, and the surface of the base material becomes bumpy as if covered with frost, it is limited to the above range.

The source of the fluorine ions is one which is soluble in the acidic film chemical conversion treatment agent, can form a complex with aluminum, and does not exhibit the effect of a reaction on the chemical conversion treatment. There is no particular limitation as long as it is present, and examples thereof include hydrofluoric acid, hydrofluoric acid, and boric acid. When the above-mentioned zirconium or titanium complex is used as a supply source of the fluorine ions, the amount of the generated fluorine ions is insufficient. Therefore, it is preferable to use the fluorine compound in combination.

The pH of the acid film chemical conversion treatment agent is 1.5
４4.0. If the pH is less than 1.5, the surface of the aluminum substrate or the aluminum alloy substrate is unduly etched, and if the pH exceeds 4.0, the etching of the surface of the aluminum substrate or the aluminum alloy substrate is unsatisfactory. Because it is sufficient, it is limited to the above range. Preferably, p
H2.6 to 3.8.

Adjustment of the pH of the acid film chemical conversion treating agent
It is preferable to use an acid or a base which does not adversely affect the above chemical conversion treatment, such as nitric acid, ammonium hydroxide; perchloric acid, sulfuric acid and the like. When sulfuric acid is used, the pH of the acidic film chemical conversion treatment agent is preferably 2 or more.

The weight of the film formed in the above chemical conversion treatment is preferably ²⁰ to 40 mg / m ² . 20mg / m
If it is less than ^2, it is insufficient performance such as corrosion resistance, 40
If the amount exceeds mg / m ² , not only may the film become too thick and the glitter of aluminum may be impaired, but rather the corrosion resistance may be poor.

The chemical conversion treatment may be performed so that the weight of the film to be formed falls within the above range. Generally, it is preferable to perform the treatment at a treatment temperature of 35 to 45 ° C. and a treatment time of 40 to 50 seconds. More preferably, the treatment is performed at 40 ° C. for about 45 seconds. The method of the chemical conversion treatment is not particularly limited, and examples thereof include an immersion method and a spray method. The aluminum substrate or the aluminum alloy substrate is usually washed with water after the chemical conversion treatment step (2).

In the present invention, the aluminum substrate or the aluminum alloy substrate is then post-treated with a solution containing an epoxy resin in step (3). By performing the post-treatment with the solution containing the epoxy resin, a thin film having better adhesion to the coating film can be formed on the surface of the chemical conversion film, and a film having excellent corrosion resistance can be obtained.

The epoxy resin is not particularly limited as long as it has an epoxy group. For example, a glycidyl ether resin which is a condensate of bisphenol A or bisphenol F with epichlorohydrin; a phenol novolak type epoxy resin; Cresol novolak epoxy resin; polyglycidyl ester resin of polybasic carboxylic acid such as polyglycidyl acrylate; aliphatic epoxy resin such as glycidyl ether of epoxidized polybutadiene, aliphatic polyol or polyether polyol; alicyclic epoxy resin; Compounds containing two or more oxirane groups in one molecule, such as epoxy resins, may be mentioned.

As the epoxy resin, a chain extension of the epoxy resin with a bifunctional polyester polyol, polyether polyol, bisphenol, dibasic carboxylic acid or the like can be used. Further, for the purpose of adjusting the molecular weight or amine equivalent, improving the heat flow property, etc., 2-epoxyhexanol, nonylphenol, ethyleneglycol mono-2-
Ethylhexyl ether, propylene glycol mono-
A monohydroxy compound such as 2-ethylhexyl ether can be added for use.

As the above-mentioned epoxy resin, it is also possible to use a resin in which some epoxy groups have been modified with a hydratable functional group in order to dissolve them in water. Examples of the functional group include a cationic group such as an ammonium group based on an amine such as an alkanolamine, a sulfonium group based on a sulfide; an anionic group such as a carboxyl group; and a nonionic group such as a hydroxyl group. Preferably, it is a cationic group. Modification with the above functional group can be performed according to a conventional method. For example, as a method of modifying with a sulfonium group, Japanese Unexamined Patent Application Publication No. 11-209663
And the production method described in Japanese Patent Application Publication No.

The epoxy resin has a number average molecular weight of 25.
0 to 20,000 is preferred. Less than 250, 2
If it exceeds 0000, the adhesion to the coating film may be poor, or the physical properties such as corrosion resistance may be poor.

When a water-soluble epoxy resin is used, a solution containing the epoxy resin used in the step (3) can be prepared by dissolving the epoxy resin in an aqueous medium. The aqueous medium is a medium containing water as a main component, and may contain a water-soluble solvent such as an alcohol generally used when preparing an aqueous paint.

When the epoxy resin is not water-soluble, the epoxy resin is emulsified and dispersed in an aqueous medium or a neutralizing agent (acetic acid or the like) in an amount capable of neutralizing the cationic group or anionic group in each resin. The solution containing the epoxy resin used in the step (3) can be prepared by neutralizing and emulsifying and dispersing in water as an emulsion. In preparing the emulsion, it is also possible to use emulsifiers.

In the present invention, the epoxy resin was treated with a solution containing the epoxy resin because it is considered that the epoxy resin exerts an adhesive effect with the powder coating film to be subsequently applied. Thereafter, it is preferable to apply the powder coating in step (4) without curing. Therefore, the solution containing the epoxy resin used in the step (3) does not necessarily need to contain a curing agent.

The content of the epoxy resin is preferably 0.5 to 10% by weight in the above solution. 0.5
If the amount is less than 10% by weight, the adhesion of the coating film becomes insufficient and
If the content exceeds 0% by weight, the epoxy resin may agglomerate on the surface of the aluminum base material or the aluminum alloy base material, or uneven coating may occur. More preferably, 0.5
~ 5% by weight.

As a method of treating with a solution containing the above epoxy resin, it is generally preferable to carry out the treatment at a treatment temperature of 20 to 45 ° C. and a treatment time of about 30 seconds to 2 minutes. In addition, treatments such as an immersion method and a spray method can be given. The thickness obtained by treating with the solution containing the epoxy resin is preferably 0.1 to 10 μm. If it is less than 0.1 μm, the adhesion cannot be improved, and if it exceeds 10 μm, the glitter of the aluminum substrate or the aluminum alloy substrate may be impaired.

After the above step (3), the aluminum base material or the aluminum alloy base material is not washed with water,
Dried. In the present invention, from the viewpoint of improving the adhesion to the coating film, it is preferable that the epoxy resin is not completely cured or is in an uncured state and is powder-coated by the next step (4). Therefore, the drying is performed at 100 to 1
It is preferable to carry out at 40 ° C. for about 20 to 30 minutes.

In the present invention, the aluminum substrate or the aluminum alloy substrate is then subjected to powder coating in step (4). Generally, the powder coating has a high internal stress in the coating film after coating, and when powder coating is performed after performing normal pre-coating treatment, it is not possible to obtain an excellent corrosion resistance. In the present invention, by performing the step (3) of treating with the solution containing the epoxy resin, a thin film having excellent adhesion with the coating film can be formed on the surface of the chemical conversion film. Obtainable.
Powder coating is also preferred from the viewpoint of environmental safety.

The paint used for the powder coating is not particularly limited, but it is preferable to use an acrylic clear powder paint in order to maintain the glitter on the surface of the aluminum substrate and the surface of the aluminum alloy substrate. .

In the method for treating an aluminum substrate or an aluminum alloy substrate according to the present invention, as a pretreatment for coating, an acid pickling in step (1), a chemical conversion treatment in step (2), and a post-treatment in step (3) are performed. After that, powder coating is performed. Each of these steps, in the processing method of the present invention,
It plays an important role in obtaining a coated product excellent in corrosion resistance and coating film adhesion while maintaining the glitteriness of aluminum.

That is, the pickling in the above step (1) is a step for removing impurities on the surface of the base material, and the chemical conversion treatment in the above step (2) is a process for improving the transparency and the adhesiveness of the coating film. This is a process for forming a film having a high surface roughness. Further, the post-treatment in the step (3) is a step for further increasing the adhesion to the coating film and forming a thin film having excellent corrosion resistance.

Therefore, through this series of steps, the surface cleaning of the aluminum base material or the aluminum alloy base material and the provision of properties such as adhesion to the coating film and corrosion resistance are sequentially performed. Even when the powder coating is performed according to 4), a coated product which retains the brilliancy of aluminum and has excellent performance such as corrosion resistance can be obtained as compared with the conventional coating pretreatment method. An aluminum substrate or an aluminum alloy substrate treated by the above treatment method is also one of the present invention.

In the method for treating an aluminum substrate or an aluminum alloy substrate of the present invention, a treatment liquid not containing harmful substance, chromium, is used in the chemical conversion treatment. However, unlike the conventional non-chromate treatment, A film having performance equal to or higher than that of the chromate treatment can be formed. Therefore, the treatment load of the wastewater containing the chemical conversion treatment liquid can be reduced, and the coating method is also a powder coating, which is a preferable treatment method in terms of environmental hygiene from these points.

[0064]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Aluminum alloy (AC-4C) test panel and A-
Using two kinds of base materials of 1100P test panel, after performing degreasing, washing with water, and pickling treatment under the following conditions,
Water washing, chemical conversion treatment, water washing and post-treatment were performed, and after drying, powder coating was performed. Washing was performed with a tap water shower, and each step was all performed by a dip method. Drying was performed at 120 ° C. for 25 minutes using an electric dryer.

(A) Degreasing treatment solution: 2% (w / v) Surf Cleaner 53 (manufactured by Nippon Paint Co., Ltd.) Treatment temperature: 50 ° C. Treatment time: 3 minutes (B) Pickling treatment solution: 3% (w / v) v) Surf cleaner 355A (manufactured by Nippon paint Co., Ltd.; FeSO ₄ · 7H ₂ O0.81g /
L, 98% sulfuric acid 12.1 g / L, pH 0.9) Treatment temperature: 40 ° C. Treatment time: 3 minutes (C) Chemical conversion treatment Treatment liquid: 2.5% (w / v) Alsurf 501N-1
(Nippon Paint Co .; zirconium phosphate treatment agent;
_{(NH 4) 2 ZrF 6 0.12g} / L, 75% H 3 PO
₄ 0.10 g / L, 55% HF 0.02 g / L, 42%
HBF ₄ 0.16 g / L, pH 3.5) Processing temperature: 40 ° C. Processing time: 45 seconds

(D) Post-treatment Treatment solution: Powernics 110F-2 (manufactured by Nippon Paint Co .; component is a modified epoxy emulsion; non-volatile content: 36)
Wt.) Diluted with water so that the resin solid content becomes 2 wt.% Processing temperature: 25 ° C. Processing time: 1 minute (E) Powder coating Powderx A400 (acrylic powder coating, manufactured by Nippon Paint Co., Ltd.) ) Was applied to a dry film thickness of 80 μm,
Baking was performed at 60 ° C. for 20 minutes.

The film formed in the chemical conversion treatment (C)
Weight is analyzed as X-ray fluorescence by X-ray fluorescence
As a result, 30 mg / m^Two Met. For post-processing (D)
The film formed at this time is permascope (Fisher
Was 1 μm. Profit
A composite corrosion test was performed using the obtained substrate. Armini
Cutting for aluminum alloy (AC-4C) test panel
The surface and the shot surface were each tested. Table 1 shows the results
Indicated.Composite corrosion test  Put a cross cut on the coating film and spray with salt water for 17 hours → forced drying
3 hours of drying → 2 hours of salt water immersion → 2 hours of natural drying (room temperature)
Cycle [CCT (cycle corrosion)
test) cycle] for 60 cycles
The rust width (mm) on both sides of the G part was measured. Also, after the test
The following evaluation was conducted on the rust generated on the cross cut part of the base material.
And was visually confirmed. ：: Practical level. ×: Not practically feasible.

[0069]

[Table 1]

Embodiment 2 In the post-processing (D) of Embodiment 1, the power nicks 11
Instead of 0F-2, Epolite 400E (manufactured by Kyoeisha Chemical Co., Ltd .; polyethylene glycol diglycidyl ether;
Except having used the number average molecular weight 600), it processed like Example 1. The results are shown in Table 1.

Comparative Example 1 In post-processing (D) of Example 1, the power nicks 11
PC2200 (manufactured by Nippon Paint Co .; ethylene acrylic acid copolymer; number average molecular weight 10)
Except using 0), it processed like Example 1. The results are shown in Table 1.

Comparative Example 2 In the post-processing (D) of Example 1, the power nicks 11
The treatment was performed in the same manner as in Example 1 except that Julimer NP13L (manufactured by Nippon Pure Chemical Co., Ltd .; polyacrylic acid; number average molecular weight 70) was used instead of 0F-2. Table 1 shows the results
It was shown to.

Comparative Example 3 The procedure of Example 1 was repeated, except that the pickling treatment (B) was not carried out. The results are shown in Table 1.

Comparative Example 4 The procedure of Example 2 was repeated, except that the pickling treatment (B) was not carried out. The results are shown in Table 1.

Comparative Example 5 The procedure of Comparative Example 1 was repeated except that the pickling treatment (B) was not performed. The results are shown in Table 1.

Comparative Example 6 The procedure of Comparative Example 2 was repeated except that the pickling treatment (B) was not performed. The results are shown in Table 1.

From the above results, the samples treated according to the present invention are superior to the cut surface and shot surface of the aluminum alloy (AC-4C) test panel and the base material of the A-1100P test panel. Showed corrosion resistance.
In Comparative Examples 1, 2, 5, and 6, in which a resin other than the epoxy resin was used in the step (3), the corrosion resistance was poor in any of the base materials. Further, Comparative Examples 3 to 6 in which the pickling treatment was not performed were further inferior in corrosion resistance.

[0078]

The method for treating an aluminum substrate or an aluminum alloy substrate of the present invention is as described above.
Without using a harmful chromium-containing treating agent, it is possible to form a coating film that is excellent in performance such as corrosion resistance and adhesion of a powder coating film and can maintain the glitter of aluminum. Further, the aluminum substrate or aluminum alloy substrate treated by the treatment method of the present invention has corrosion resistance,
It is excellent in adhesion of a coating film and retains the brilliancy of aluminum, and can be suitably used for applications requiring a sense of quality, for example, automotive parts such as aluminum wheels.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C23C 22/78 C23C 22/78 F term (reference) 4D075 AE03 BB65X BB73Y BB92Y CA13 CA33 CB04 CB06 DA23 DB07 DC13 EA02 EA06 EA43 EB22 EB33 4F100 AA21B AA27B AB10A AK25 AK53C BA04 BA07 BA10A BA10D CC10D DE01D GB32 JB02 YY00B 4K026 AA09 BA03 BB01 BB07 BB08 CA13 CA18 CA23 CA24 CA26 CA28 DA03 DA06 DA13 DA16 EA07 EB08 CA04 BC04 BC04 BC04 ABC03

Claims (4)

[Claims] 1. A step (1) of treating an aluminum substrate or an aluminum alloy substrate with an acidic aqueous solution containing 0.1 to 0.4 g / L of ferric ions and sulfate ions and having a pH of 0.6 to 2.0. , Zirconium ion or titanium ion 0.01-0.125 g / L, phosphate ion 0.01-
1.0 g / L and fluorine ion 0.01 to 0.5 g
/ L and a chemical conversion treatment with an acidic chemical treatment agent having a pH of 1.5 to 4.0, a step (3) of treating with a solution containing an epoxy resin, and a step (4) of powder coating. A method for treating an aluminum substrate or an aluminum alloy substrate, comprising: 2. The processing method according to claim 1, wherein the aluminum substrate or the aluminum alloy substrate is a wheel. 3. The treatment method according to claim 1, wherein the weight of the film formed in the chemical conversion treatment step (2) is 5 to 50 mg / m ² . 4. An aluminum substrate or an aluminum alloy substrate treated by the treatment method according to claim 1, 2 or 3.