JP4046792B2 - Anionic electrodeposition coating and method for forming coating film using the same - Google Patents

Description

【００５７】
【表２】

【００５８】
表３に艶消し電着塗料の塗膜外観の結果を示す。
【００５９】
【表３】

【００６０】
塗料貯蔵安定性及び塗膜外観の試験評価は次の通りである。
【００６１】
塗料貯蔵安定性：塗料を試験管（高さ２０ｃｍ、容量２０ｃｃ）に充填し、２０℃で７日間静置した後、容器の底に沈殿した残渣の高さを調べた。◎は残渣が０．５ｍｍ以下で良好、○は残渣が０．６〜５ｍｍでほぼ良好、△は残渣が６〜１０ｍｍでやや不良、×は１１ｍｍ以上で不良のもの
鏡面反射率：ＪＩＳ Ｋ−５４００の６０度鏡面反射率を測定した
平滑性：塗膜表面（ユズ肌、凹凸等）を目視で評価した。◎は良好、○はほぼ良好、△はやや不良、×は不良のもの
耐ストライプ性：ストライプ（塗液筋）による光沢変化を肉眼で調べた。◎は良好、○はほぼ良好、△はやや不良、×は不良を示す
耐乾きムラ性：塗膜表面の乾きムラの光沢変化を肉眼で調べた。◎は良好、○はほぼ良好、△はやや不良、×は不良を示す
素地の影響：○は塗膜が若干濁って素材のダイス目が目立たないもの、×は塗膜がクリヤーで素地のダイス目が目立つもの。
【００６２】
【発明の効果】
本発明塗料は、特定の有機溶剤を含有していることから、特に、乾きムラ、ストライプ等の塗膜欠陥がなく、平滑性に優れた塗膜を形成することができる。
【００６３】[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel anionic electrodeposition coating material and a coating film forming method using the same.
[0002]
[Prior art]
At present, an anodized electrodeposition paint having a good finish and one coat is applied to an anodized aluminum sash or the like.
[0003]
As a method for applying the above electrodeposition paint, an extra paint (coating solution) adheres to the deposited film of the electrodeposition paint when the object is electrodeposited in the electrodeposition paint bath and then pulled up from the bath. Therefore, an electrodeposition coating method is known in which the coating liquid is removed by setting (non-rinsing) or washing with water (such as clean water or RO permeated water) (rinsing) and then baked.
[0004]
However, conventionally used electrodeposition paints have a problem that the finished appearance such as gloss, dry unevenness, and smoothness of the coating film is inferior.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to develop an anionic electrodeposition coating material having improved coating appearance of a conventional anionic electrodeposition coating material and a method for forming the coating film.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an anionic electric battery comprising 0.001 to 2.0% by weight of a hydrophobic organic solvent having a boiling point of 200 ° C. to 400 ° C. The present inventors have found that the coating material can provide a coating film having an excellent finished appearance and thus completed the present invention.
[0007]
That is, the present invention
1. An anionic electrodeposition paint comprising 0.001 to 2.0% by weight of a hydrophobic organic solvent having a boiling point of 200 ° C to 400 ° C,
2. The anionic electrodeposition paint as described above, wherein the hydrophobic organic solvent has a solubility (g amount of the organic solvent dissolved in 100 g of water at 20 ° C.) in a range of less than 5.0.
3. An anodized aluminum substrate is electrodeposited in an anionic electrodeposition coating containing 0.001 to 2.0% by weight of a hydrophobic organic solvent having a boiling point of 200 ° C. to 400 ° C., and then obtained. In addition, the present invention relates to a method for forming a coating film, characterized in that the electrodeposited coating is washed with water as necessary and then baked.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The organic solvent referred to in the present invention is a hydrophobic organic solvent having a boiling point of 200 ° C. to 400 ° C., preferably 220 ° C. to 300 ° C. When the boiling point is lower than 200 ° C, the organic solvent volatilizes while setting the electrodeposition coating (before baking), causing the coating film to dry unevenly due to the coating liquid and washing water, and drooping stripes (stripe). However, when the temperature exceeds 400 ° C., this remains in the baked coating film and the coating film performance deteriorates. The hydrophobicity of the organic solvent is inferior in solubility in water, and the solubility (the number of grams of the organic solvent dissolved in 100 g of water at 20 ° C.) is particularly less than 5.0, especially 0.1 to 4. A range of .8 is preferred. When the solubility is 5.0 or more, improvement in coating defects such as drying unevenness, stripes, smoothness, and gloss due to the coating liquid or washing water is not preferable.
[0009]
As the hydrophobic organic solvent, conventionally known organic solvents can be appropriately selected and used as long as they satisfy the above conditions. Specifically, for example, ethylene glycol mono-2-ethylhexyl ether (boiling point 229 ° C., solubility 0.2), diethylene glycol mono-2-ethylhexyl ether (boiling point 272 ° C., solubility 0.3), dipropylene glycol monopropyl ether (boiling point 212). ° C, solubility 4.8), tripropylene glycol mono n-butyl ether (boiling point 274 ° C, solubility 3.0), ethylene glycol monophenyl ether (boiling point 244 ° C, solubility 2.7), propylene glycol monophenyl ether (boiling point 242) C, solubility 0.2), (CH3) 2CHCOOCH2C (CH3) 2CH (OH) CH (CH3) 2 (boiling point 390 ° C, solubility 0.2) and the like. These organic solvents can be used alone or in combination of two or more. Among these, diethylene glycol monoalkyl ether and diethylene glycol phenyl ether are particularly preferable.
[0010]
The content of the above-mentioned hydrophobic organic solvent is 0. 0 to the coating bath (generally, a bath paint or line paint having a solid content in the range of about 5 to 25% by weight, preferably about 6 to 20% by weight). The range is 001 to 2.0% by weight, preferably 0.01 to 0.5% by weight. If the content is less than 0.001% by weight, the coating film may have drying defects, stripes, etc., and the coating film smoothness, gloss, etc. may be inferior. Stability and electrodeposition characteristics deteriorate (a uniform deposited coating cannot be obtained). As a result, the finished appearance such as the smoothness of the coating is deteriorated. And scratch resistance are deteriorated.
[0011]
The anionic electrodeposition coating referred to in the present invention is generally known and includes an aqueous base resin containing a carboxyl group and a hydroxyl group in the skeleton, an amino resin, and a crosslinking agent such as a block polyisocyanate compound. The vehicle component is neutralized with a neutralizing agent such as amine and then dispersed in water.
[0012]
Examples of the aqueous base resin include vinyl copolymers, polyester resins, alkyd resins, fluororesins, and silicone resins. These resins can be used alone or in combination of two or more. Among these, it is preferable to use the following vinyl copolymer.
[0013]
Examples of the vinyl copolymer include vinyl copolymers obtained by radical copolymerization reaction of a hydroxyl group-containing vinyl monomer, an ethylenically unsaturated carboxylic acid and, if necessary, other unsaturated monomers.
[0014]
Examples of these monomer components include the following.
[0015]
(1) Hydroxyl-containing vinyl monomers: for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (poly) ethylene glycol mono (meth) Acrylate, (poly) propylene glycol mono (meth) acrylate, hydroxybutyl vinyl ether, (meth) allyl alcohol, and hydroxyl group-containing vinyl monomers and β-propiolactone, dimethyl As a product name, such as a reaction product with a lactone compound such as propiolactone, butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprolactone, γ-lauryllactone, ε-caprolactone, δ-caprolactone, etc. PLACCEL FM1 (manufactured by Daicel Chemical Industries, trade name, caprolactone modified (meta Acrylic acid hydroxy esters), PLACCEL FM2 (Same as left), PLACCEL FM3 (Same as left), Placcel FA-1 (Same as left), PLACCEL FA2 (Same as left), PLACCEL FA3 (Same as left) or the like.
[0016]
(2) Ethylenically unsaturated carboxylic acids: For example, (meth) acrylic acid, maleic acid, Plaxel FM1A (hereinafter referred to as Daicel Chemical Industries, Ltd., caprolactone-modified carboxyl group-containing (meth) acrylic monomer, trade name), Plaxel FM4A, PLACCEL FM10A etc.
[0017]
(3) Other unsaturated monomers: for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth C1-18 alkyl or cycloalkyl esters of (meth) acrylic acid such as octyl acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, aromatic vinyl monomers such as styrene, (meth) acrylic (Meth) acrylamide and derivatives thereof such as acid amide, N-butoxymethyl (meth) acrylamide, N-methylol (meth) acrylamide, (meth) acrylonitrile compounds, etc., γ- (meth) acryloxypropyltrimethoxy Silane, γ- (meth) acryloxypropylmethyldimethoxysilane Alkoxysilyl group-containing vinyl monomers such as γ- (meth) acryloxypropyltriethoxysilane and vinyltrimethoxysilane.
[0018]
In the blending ratio of these monomers, the hydroxyl group-containing monomers may be blended so that the hydroxyl value of the copolymer falls within the range of about 30 to 300 mg KOH / g. The amount of hydroxyl group-containing monomers is about 3 to 40% by weight, preferably about 5 to 30% by weight in terms of amount.
[0019]
The ethylenically unsaturated carboxylic acid may be blended so that the acid value of the copolymer falls within the range of about 10 to 200 mg KOH / g. However, the ethylenically unsaturated carboxylic acid is ethylenic with respect to the total amount of monomers. The unsaturated carboxylic acid ranges from about 3 to 30% by weight, preferably from about 4 to 20% by weight.
[0020]
As other unsaturated monomers, it is preferable to use C1-C18 alkyl or cycloalkyl esters of (meth) acrylic acid and aromatic vinyl monomers such as styrene. The blending amount of the monomers is about 37 to 95% by weight, preferably about 60 to 91% by weight, based on the total amount of the monomers.
[0021]
The radical copolymerization can be performed by a conventionally known solution polymerization method or the like.
[0022]
As the crosslinking agent, for example, a part or all of the methylol group of the melamine resin is modified with one or more monohydric alcohols such as methanol, ethanol, propanol, butanol, octyl alcohol, 2-ethylhexyl alcohol and the like. Can be used. The melamine resin is preferably a mononuclear to multi (about 2 to 5) nuclei occupying 50% by weight or more. The melamine resin may contain other functional groups such as an imino group and a methylol group. Further, the matte electrodeposition coating material has an average of about 2.0 or more, especially 2.0 to 1, ether groups modified with C3 or higher monohydric alcohol, particularly C4-18 monohydric alcohol per triazine ring. It is preferable to contain 5.0.
[0023]
Examples of the block polyisocyanate crosslinking agent include isophorone diisocyanate, hexamethylene diisocyanate and the like “aliphatic and alicyclic polyisocyanate compounds, lactones such as ε-caprolactone, methanol, ethanol, propanol, butanol, pentanol, and the like. And alcohols blocked with oximes such as methyl ethyl ketoxime and methyl isobutyl ketoxime can be used.
[0024]
In the paint of the present invention, the blending ratio of the aqueous base resin and the crosslinking agent is 40 to 85% by weight, preferably 50 to 80% by weight, based on the total measured solid content of both, and the crosslinking agent. Is in the range of 15-60% by weight, preferably 20-50% by weight. When the blending ratio of the aqueous base resin is less than 40% by weight and the crosslinking agent exceeds 60% by weight, the coating performance such as weather resistance and processability is deteriorated, while the blending ratio of the aqueous base resin is 85% by weight. If it exceeds the upper limit and the crosslinking agent is less than 15% by weight, the coating film performance such as weather resistance, scratch resistance and processability is deteriorated.
[0025]
The paint of the present invention can be blended with pigments, dyes, fluidity modifiers and the like as necessary.
[0026]
The paint of the present invention may be any type of paint such as a bath paint, a replenishing paint, and a line paint, but is particularly preferably used as a line paint. As the line paint, for example, the hydrophobic organic solvent can be directly mixed or mixed with a hydrophilic organic solvent in a line paint that has already been used.
[0027]
In the paint of the present invention, in addition to the hydrophobic organic solvent having a boiling point of 200 ° C. to 400 ° C., a hydrophilic organic solvent such as propyl alcohol, butyl cellosolve and butanol is about 0.2 to 3.0% by weight, preferably about 0.3%. When it is contained in the range of ˜2.5% by weight, a coating film having an excellent finished appearance (stripe property) is formed. Therefore, it is desirable to use these in combination.
[0028]
The paint of the present invention can be used as a glossy or matte paint and can form a coating film by the following non-rinse or rinse coating method. When a paint film is formed by non-rinsing or rinsing using a glossy paint, a paint film having excellent smoothness can be formed without any coating defects such as dry unevenness and sagging streaks. Since the organic solvent uses a specific amount of an organic solvent that is hydrophobic and has an appropriate boiling point, the storage stability of the electrodeposition paint is excellent. Also, in electrodeposition coating, after the object to be coated is lifted from the electrodeposition bath, the deposited coating is difficult to dry during setting up to baking, so there is no drying unevenness. In baking, the organic solvent is deposited. The thermal fluidity of the film is promoted, so that a coating film having no gloss unevenness and excellent smoothness is formed, and the organic solvent does not remain in the coating film after baking, so that the coating film performance is not deteriorated.
[0029]
When a paint film is formed by rinsing using a matte paint, the clear coating film becomes slightly cloudy because the organic solvent is incompatible with the electrodeposition paint resin composition in addition to the same effects as described above. Is formed. For this reason, for example, the effect of concealing the base (die) of aluminum building material is recognized.
[0030]
The paint of the present invention is particularly preferably applied to the field of aluminum building materials using a colored or non-colored anodized aluminum material.
[0031]
In the coating film forming method of the present invention, the anionic electrodeposition paint obtained above is used as an electrodeposition paint bath, and after the aluminum material is immersed in this bath, the dry film thickness is about 5 to 30 microns. After anionic electrodeposition coating, without washing with water (non-rinse) or with water (rinse), and then setting at room temperature, the coating is applied by baking (for example, about 160 to 200 ° C. for about 20 to 40 minutes). Can be formed.
[0032]
【Example】
The present invention will be described in detail with reference to examples. The invention is not limited to the examples provided.
[0033]
Production Example of Acrylic Copolymer (a) 70 g of isopropyl alcohol was charged into a reaction vessel and maintained at 80 ° C., 10 g of styrene, 31 g of methyl methacrylate, 10 g of n-butyl acrylate, ethyl acrylate 30 g, a mixture of 12 g of 2-hydroxyethyl acrylate, 7 g of acrylic acid, and 2 g of azobisdimethylvaleronitrile was added dropwise over 3 hours, then 1 g of azobisdimethylvaleronitrile was added and held at 80 ° C. for 1 hour Thus, a reactive copolymer (a) varnish was produced. The copolymer had a weight average molecular weight of about 20,000, an acid value of 55 mgKOH / g, and a hydroxyl value of 58 mgKOH / g. This copolymer (a) is used for glossy electrodeposition paints.
[0034]
Production Example of Acrylic Copolymer (b) 70 g of isopropyl alcohol was charged into a reaction vessel and maintained at 80 ° C., and 10 g of styrene, 24 g of methyl methacrylate, 7 g of γ-methacryloxypropyltrimethoxysilane, A mixture of 10 g of n-butyl acrylate, 30 g of ethyl acrylate, 12 g of 2-hydroxyethyl acrylate, 7 g of acrylic acid and 2 g of azobisdimethylvaleronitrile was added dropwise over 3 hours, and then 1 g of azobisdimethylvaleronitrile. And kept at 80 ° C. for 1 hour to produce a reactive copolymer (b) varnish. The copolymer had a weight average molecular weight of about 25,000, an acid value of 55 mgKOH / g, and a hydroxyl value of 58 mgKOH / g. This copolymer (b) is used for matte electrodeposition coatings.
[0035]
Example 1
After blending 0.4 equivalent of triethylamine with respect to the carboxyl group of the copolymer (a) into 7 Kg (solid content) of the copolymer (a), the mixture was mixed and dispersed, and then Nicalak MX600 (Sanwa) (Chemical Co., Ltd., trade name, butoxylated melamine resin) After mixing and dispersing 3 kg, deionized water is gradually added dropwise with stirring, and triethylamine is added so that the pH becomes 8.0. A glossy electrodeposition coating material of Example 1 of% by weight was produced. Subsequently, the paint was aged by releasing and stirring at 30 ° C. for 7 days. The aging is produced assuming a line paint that has been run. Volatile water and isopropanol were added by aging, and butyl cellosolve and diethylene glycol mono-2-ethylhexyl ether (boiling point 272 ° C., solubility 0.3) were added. The obtained clear glossy paint had a solid content of 10% by weight, isopropanol 2.0% by weight, butyl cellosolve 1.2% by weight, butanol 1.1% by weight, and diethylene glycol mono-2-ethylhexyl ether 0.2% by weight.
[0036]
Example 2
A clear glossy electrodeposition paint of Example 2 was produced in the same manner as in Example 1 except that 0.2% by weight of diethylene glycol mono-2-ethylhexyl ether was changed to 0.4% by weight.
[0037]
Example 3
In Example 1, in place of diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether (boiling point 244 ° C., solubility 2.7) was used in the same manner as in Example 1 except that 0.2% by weight was used. A clear glossy electrodeposition paint was produced.
[0038]
Example 4
In Example 1, in place of diethylene glycol mono-2-ethylhexyl ether, propylene glycol monophenyl ether (boiling point 242 ° C., solubility 0.2) was used in an amount of 0.2% by weight. A clear glossy electrodeposition paint was produced.
[0039]
Example 5
Example 1 Example 1 was carried out in the same manner as Example 1 except that 7 kg of the copolymer (a) was replaced with a pigment dispersion resin of 7 kg of the copolymer (a) and 7 kg of titanium dioxide, and the amount of water was increased. A white glossy paint having a solid content of 10% by weight was obtained. The solvent composition is the same as in Example 1.
[0040]
Example 6
In Example 1, the copolymer (a) was changed to the copolymer (b), and Nicarak MX-600 was changed to Nicarak MX-430 (manufactured by Sanwa Chemical Co., Ltd., trade name, about 3 methyl groups per melamine nucleus). The matte clear coating material of Example 6 having a solid content of 10% by weight was obtained in the same manner as in Example 1 except that the same amount was used.
[0041]
Example 7
The clear matte electrodeposition paint of Example 7 was produced in the same manner as in Example 6 except that 0.2% by weight of diethylene glycol mono-2-ethylhexyl ether was changed to 0.4% by weight.
[0042]
Example 8
In Example 6, in place of diethylene glycol mono-2-ethylhexyl ether, 0.2% by weight of ethylene glycol monophenyl ether (boiling point 244 ° C., solubility 2.7) was used. A clear matte electrodeposition paint was produced.
[0043]
Example 9
In Example 6, in place of diethylene glycol mono-2-ethylhexyl ether, propylene glycol monophenyl ether (boiling point 242 ° C., solubility 0.2) was used in an amount of 0.2% by weight. A clear matte electrodeposition paint was produced.
[0044]
Comparative Example 1
A clear glossy electrodeposition paint of Comparative Example 1 was produced in the same manner as in Example 1 except that diethylene glycol mono-2-ethylhexyl ether was not used at all.
[0045]
Comparative Example 2
A clear glossy electrodeposition paint of Comparative Example 2 was produced in the same manner as in Example 1 except that 0.2% by weight of diethylene glycol 2-ethylhexyl ether was changed to 2.1% by weight.
[0046]
Comparative Example 3
In Example 1, the same amount of ethylene glycol mono n-butyl ether (boiling point 170 ° C., solubility 6.0 g) was used instead of diethylene glycol mono 2-ethylhexyl ether, and the clear gloss of Comparative Example 3 was used. An electrodeposition paint was produced.
[0047]
Comparative Example 4
In the same manner as in Example 1 except that propylene glycol mono n-butyl ether (boiling point 230 ° C., solubility 5.0 g) was used instead of diethylene glycol mono 2-ethylhexyl ether in Example 1, the clear gloss of Comparative Example 4 was used. An electrodeposition paint was produced.
[0048]
Comparative Example 5
In Example 5, a white glossy electrodeposition coating material of Comparative Example 5 was produced in the same manner as Example 5 except that diethylene glycol mono-2-ethylhexyl ether was not used at all.
[0049]
Comparative Example 6
A clear matte electrodeposition coating of Comparative Example 6 was produced in the same manner as in Example 6 except that no diethylene glycol mono-2-ethylhexyl ether was used in Example 6.
[0050]
Comparative Example 7
A clear matte electrodeposition paint of Comparative Example 7 was produced in the same manner as in Example 6 except that 0.2% by weight of diethylene glycol 2-ethylhexyl ether was changed to 2.1% by weight.
[0051]
Comparative Example 8
In Example 6, the same amount of ethylene glycol mono n-butyl ether (boiling point 170 ° C., solubility 6.0 g) was used in place of diethylene glycol mono-2-ethylhexyl ether, and the clear gloss of Comparative Example 8 was used. An erase electrodeposition paint was produced.
[0052]
Comparative Example 9
In Example 6, the clear gloss of Comparative Example 9 was used in the same manner as in Example 6 except that the same amount of propylene glycol mono n-butyl ether (boiling point: 230 ° C., solubility: 5.0 g) was used instead of diethylene glycol mono-2-ethylhexyl ether. An erase electrodeposition paint was produced.
[0053]
Painting method (non-rinse):
The electrodeposition paint obtained in the above-mentioned Examples and Comparative Examples was used as an electrodeposition bath, and an object to be coated (an anodized aluminum material having a film thickness of about 10 microns) (size is 1 m long × 0.1 m wide). X thickness 0.5mm) is vertically suspended and dipped, anion electrodeposition coating is performed so that the dry film thickness is about 10 microns, and then the coated material is pulled up from the bathtub, and then the humidity is 70% at 20 ° C. It was left to stand for about 2 minutes in the atmosphere (until the coating solution hangs down), and then baked at 170 ° C. for 30 minutes to form coating films of Examples and Comparative Examples.
[0054]
Painting method (rinse):
After performing the anion electrodeposition coating by the method of coating method I described above, the coated material is pulled up from the bathtub and washed with water at 20 ° C. and then baked at 170 ° C. for 30 minutes to form the coating films of the examples and comparative examples. Formed.
[0055]
Tables 1 and 2 show the results of the coating film appearance of the glossy electrodeposition paint.
[0056]
[Table 1]

[0057]
[Table 2]

[0058]
Table 3 shows the results of the paint film appearance of the matte electrodeposition paint.
[0059]
[Table 3]

[0060]
Test evaluations of paint storage stability and coating film appearance are as follows.
[0061]
Paint storage stability: The paint was filled in a test tube (height 20 cm, capacity 20 cc) and allowed to stand at 20 ° C. for 7 days, and then the height of the residue precipitated on the bottom of the container was examined. ◎ is good when the residue is 0.5 mm or less, ○ is almost good when the residue is 0.6 to 5 mm, Δ is slightly bad when the residue is 6 to 10 mm, x is bad when it is 11 mm or more, and mirror reflectivity: JIS K- Smoothness obtained by measuring 60 ° specular reflectance of 5400: The coating film surface (skin skin, unevenness, etc.) was visually evaluated. ◎ is good, ○ is almost good, Δ is slightly bad, x is bad. Strip resistance: Gloss change due to stripes (coating lines) was examined with the naked eye. ◎ is good, ○ is almost good, Δ is slightly poor, and x is poor. Drying unevenness resistance: The gloss change of dry unevenness on the coating film surface was examined with the naked eye. ◎: Good, ○: Almost good, △: Slightly poor, ×: Poor substrate effect: ○: Slightly turbid coating material with inconspicuous material dies, ×: Clear coating substrate dies Things that stand out.
[0062]
【The invention's effect】
Since the coating composition of the present invention contains a specific organic solvent, it is particularly free from coating film defects such as uneven drying and stripes, and can form a coating film excellent in smoothness.
[0063]

Claims (2)

4. An anionic electrodeposition paint that is electrodeposited onto an anodized aluminum substrate, the boiling point of which is 200 ° C. to 400 ° C., and the solubility is the number of grams dissolved in 100 g of water at 20 ° C. A hydrophobic organic solvent in a range of less than 0 is blended in the electrodeposition paint in an amount of 0.001 to 2.0% by weight, and the hydrophobic organic solvent is diethylene glycol monomer ethyl hexyl ether, ethylene glycol monophenyl ether and propylene. An anionic electrodeposition paint characterized by being selected from glycol monophenyl ether . The anodized aluminum base material is electrodeposited in the anionic electrodeposition paint according to claim 1 , and then the obtained electrodeposition coating is washed with water or baked without washing. Coating film forming method.