JPH04277577A - Coating composition and coated aluminum material - Google Patents

Abstract

PURPOSE:To provide a coating compsn. which gives a coating film excellent in corrosion resistance, electrodeposition coating properties, etc., and an aluminum material coated with the compsn. and excellent in formability. CONSTITUTION:A coating compsn. which contains a bisphenol epoxy resin consisting of bisphenol A units, bisphenol F units, and epichlorohydrin units and a lubricant powder having a mean particle diameter of 0.1-20mum, and an aluminum material coated with the compsn.

Description

[Detailed description of the invention]

[0001] The present invention relates to a coating composition capable of forming a coating film having excellent corrosion resistance, electrodeposition coating properties, etc. on an aluminum material, and a coating film obtained from the coating composition having moldability, etc. Regarding coated aluminum materials with excellent properties.

0002

BACKGROUND OF THE INVENTION In recent years, aluminum materials made of aluminum or aluminum alloys have come to be used as outer panels of automobile bodies because of their light weight. That is, automobile bodies constructed by assembling steel materials and aluminum materials as outer panels of automobile bodies are being put on the market.

By the way, there is one method for manufacturing an automobile body constructed by assembling such steel materials and aluminum materials.
As one of the methods, the following method is adopted.

[0004] Steel material forming process─
┐│→Assembly→Degreasing→Aluminum molding ┘
Chemical treatment → Electrodeposition painting → Intermediate coating → Top coating

[0005] However, in the above conventional method, the press moldability of aluminum material is poor, and when the press oil or rust preventive oil used during molding is aluminum material,
Compared to steel materials, it is difficult to degrease sufficiently, and as a result, when subjected to reinforcement treatment such as zinc phosphate treatment, uneven chemical conversion treatment occurs on the surface of the aluminum material, reducing corrosion resistance, waterproof secondary adhesion, etc. Aluminum elution occurs during
There is a problem in that if the amount exceeds a certain amount, the progress of the chemical conversion treatment is hindered. Furthermore, contact between the steel material and the aluminum material is unavoidable, and as a result, there is a problem that electrical corrosion of the aluminum material occurs due to contact between different metals.

On the other hand, in order to improve the above-mentioned problems, for example to improve the formability, methods of changing the metal composition in the aluminum alloy (JP-A-58-171547, JP-A-61-201748, JP-A-Sho 61-201748, JP-A-Sho 61-201748, No. 61-201749,
JP-A No. 62-27544, etc.), a method of roughening the surface of aluminum material (JP-A No. 61-276707, JP-A-1-21047, etc.), etc., but the corrosion resistance, water resistant secondary adhesion, There is no solution to the problem of preventing electrolytic corrosion.

[0007] In addition, in order to prevent uneven chemical conversion treatment, methods for chemically cleaning the surface of aluminum materials (JP-A-1-240675, JP-A-1-279788, JP-A-2-57692, etc.), There is a method of completely degreasing by lowering the viscosity of rust oil (Japanese Patent Application Laid-Open No. 2-115385, etc.), and there is also a method of specifying the surface area ratio of aluminum and steel to enable the same chemical conversion treatment of both materials (
JP-A No. 61-104089, etc.), but none of them have solved the problem of moldability or the like.

[0008] Therefore, in the conventional method described above, a method has been considered in which the surface of the aluminum material is pre-primed, and a coated aluminum material coated with paint is used to form and assemble it with steel materials, but chemical conversion treatment in the post-process is considered. There are problems such as the coating is easy to peel off, resulting in a decrease in corrosion resistance, poor electrodeposition coating properties in post-processes, and poor moldability. A practical coating material that satisfies processability, electrodeposition coating properties, etc. has not yet been developed.

In view of the current situation, the present invention provides a coating composition for obtaining an aluminum material with excellent chemical conversion resistance, corrosion resistance, moldability, electrodeposition coating property, etc., and a coated aluminum material coated with the same. The purpose is to provide the following.

0010

[Means for Solving the Problems] That is, the present invention provides (i)
Consisting of a bisphenol skeleton consisting of a weight ratio of bisphenol A skeleton to bisphenol F skeleton (95:5 to 60:40) and an epichlorohydrin skeleton,
A bisphenol type epoxy resin having two or more epoxy groups in one molecule, and (ii) an average particle size of 0.1 to
The present invention relates to a coating composition for aluminum material containing a 20 μm lubricant powder; and a coated aluminum material in which the coating composition is applied to the surface of the aluminum material which has been pretreated.

The present invention will be explained in detail below. Bisphenol-type epoxy resin (
i) is a resin having two or more epoxy groups in one molecule, which is composed of a bisphenol skeleton and an epichlorohydrin skeleton obtained by condensing bisphenols consisting of bisphenol A and bisphenol F with epichlorohydrin according to a conventional method. Yes, preferably with a molecular weight of approx.
500 to 100,000 resin. For the condensation reaction between bisphenols and epichlorohydrin, it is appropriate to mix bisphenol A and bisphenol F and react with epichlorohydrin at the same time. The present invention also includes an epoxy resin obtained by reacting the obtained epoxy resin or bisphenol F with epichlorohydrin, and further adding and reacting bisphenol A.

By the way, bisphenol A type epoxy resin, which is obtained only from bisphenol A as a bisphenol, provides a coating film with excellent water resistance, chemical resistance, etc.
While it has excellent adhesion to aluminum materials and top coats, the paint film is hard and has poor flexibility, and is electrically insulating, so its electrodepositability is somewhat poor. Ta.

[0013] The present inventors therefore attempted to use a blend of bisphenol A type epoxy resin and bisphenol F type epoxy resin, but it was found that the electrodeposition coating properties were not improved. On the other hand, when using a bisphenol-type resin having two or more epoxy groups in one molecule, which is composed of a bisphenol skeleton consisting of a specific ratio of a bisphenol A skeleton and a bisphenol F skeleton and an epichlorohydrin skeleton, unexpected molding results may occur. It was found that both processability and electrodeposition coating properties were significantly improved.

[0014] In order to exhibit such effects, it is appropriate that the weight ratio of the bisphenol A skeleton to the bisphenol F skeleton is (95:5 to 60:40). If the bisphenol A skeleton is more than the above range, the effect of substitution with the bisphenol F skeleton will not be sufficiently recognized, and conversely, if the bisphenol A skeleton is less than the above range, the coating film will become too soft and the corrosion resistance, water resistance, etc. will decrease. So I don't like it.

[0015] Furthermore, the bisphenol type epoxy resin used in the present invention has 20% of the epoxy group of the resin in order to further improve alkali resistance, water resistance and secondary adhesion.
Modified epoxy resins that are 100% modified with basic nitrogen compounds or polybasic acids can also be used. In addition, examples of the basic nitrogen compound include n-propylamine, is
o-propylamine, n-butylamine, sec-
Butylamine, tert-butylamine, diethylamine, ethylenediamine, diethylenetriamine, triethylenediamine, tetraethylenediamine, propylenediamine, N-methylpiperazine, ethanolamine,
Diethanolamine, N-methylethanolamine, i
Typical examples include so-propanolamine, diisopropanolamine, n-propanolamine, ethylethanolamine, and 3-methanolpiperidine.

[0016] Further, as the polybasic acid, isophthalic acid,
Typical examples include terephthalic acid, succinic acid, adipic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, phthalic anhydride, succinic anhydride, citric acid, tartaric acid, oxalic acid, rosin maleic anhydride, benzenetricarboxylic anhydride, etc. It is mentioned as something like that. The lubricant powder (ii) constituting the coating composition of the present invention is desirably one that maintains its powder form at room temperature and after coating film formation, and the lubricant powder roughens the surface of the resulting coating film, It is blended to provide lubricity, that is, to reduce the coefficient of dynamic friction, and to improve the formability, particularly press formability, of the coated aluminum material. Typical examples of such lubricant powder include synthetic wax powder and solid lubricant powder.

Synthetic wax powders include synthetic hydrocarbons; fatty acid esters; fatty acid nitrogen derivatives such as fatty amides and substituted amides; modified waxes such as montan wax derivatives and montan oxide wax; polymeric compounds such as polyethylene wax; chlorinated paraffins. Typical waxes include chlorinated waxes such as chlorinated waxes, but synthetic wax powders that have a saponification value, are poorly soluble in solvents, and have a high melting point are particularly desirable.

Solid lubricant powders include layered solid lubricants such as graphite, molybdenum disulfide, tungsten disulfide, boron nitride, and graphite fluoride; polyvinyl chloride;
Typical examples include plastic lubricants such as polystyrene, polymethyl (meth)acrylate, polyamide, high-density polyethylene, polypropylene, and polytetrafluoroethylene; metal soaps containing fatty acids such as calcium, barium, lithium, zinc, and aluminum. However, plastic lubricants with particularly high surface smoothness,
Metallic soap is preferred.

It is recommended that such a lubricant powder be blended in an amount of about 1 to 50 parts by weight to 100 parts by weight of the above-mentioned bisphenol type epoxy resin in order to exhibit the lubricity of the coating film and to improve the physical and chemical properties of the coating film. It is desirable because the target strength is also moderate. In addition, the appropriate particle size of the lubricant powder is an average particle size of about 0.1 to 20 μm; if it is too small, such as less than 0.1 μm, the lubricant particles will be difficult to expose on the coating film, so the lubricant powder will be difficult to expose. 20μ
If it is too large, exceeding m, there will be problems with the film-forming properties of the coating and the stability of the coating. Note that the preferred range of particle size of the lubricant powder is 0.5 to 12 μm.

The coating composition of the present invention comprises the above-described bisphenol-type epoxy resin (i) and lubricant powder (ii).
The paint preferably has a solid content of 10 to 40% by weight. As other components, conventionally known components that are appropriately blended as necessary are blended. Specifically, water, organic solvents such as various hydrocarbons, esters, ketones, alcohols, and amide; crosslinking agents such as melamine resin, benzoguanamine resin, and polyblocked isocyanate compounds; organic or inorganic pigments; dispersion It is possible to add additives such as antisettling agents, antisettling agents, and leveling agents, or various modified resins.

Next, the method for manufacturing the coated aluminum material of the present invention will be explained. Examples of the aluminum material used in the present invention include non-heat-treated Al-Mg 5000-series metals, heat-treated Al-Cu-Mg 2000-series alloys, which are used in ordinary molded products. Heat treatment type Al-Mg-Zn 7000 series alloy, heat treatment type Al-
Mg-Si 6000 series alloy, non-heat treated Al-Mn
Typical examples include 3000 series alloys and 4000 series alloys, and 1000 series wrought materials of non-heat-treated pure aluminum, but are not limited to these.

[0022] The aluminum materials used in the present invention are subjected to chromium-based treatment by conventional means such as reactive chromate treatment such as chromium chromate or phosphoric acid chromate treatment, coating type chromate treatment, electrolytic chromate treatment, or phosphoric acid chromate treatment. This is an aluminum material that has undergone surface treatment using non-chromium-based treatments such as zircon treatment, silane coupling treatment, titanium coupling treatment, zircon coupling treatment, and aluminum coupling treatment.

[0023] The above-mentioned coating composition is applied to the surface of the aluminum material which has been subjected to the base treatment by means such as spraying, roll coating, shower coating, etc., and then heated at 80 to 300°C.
Preferably, the coated aluminum material is produced by curing at a temperature of 100 to 250°C. It should be noted that although a thin film of around several μm in thickness can exhibit sufficient performance, it is not prohibited to make the film even thicker.

The thus obtained coated aluminum material is subjected to electrodeposition coating or ordinary top coating, and is applied to fields such as automobile bodies, home appliances, and building materials.

[0025]

Effects of the Invention By coating coated aluminum materials with the coating composition of the present invention, products with excellent corrosion resistance, electrodeposition coating properties, adhesion properties, moldability, etc. can be obtained. In addition, in the above-mentioned manufacturing method of an automobile body constructed by assembling steel materials and aluminum materials, when the coated aluminum material of the present invention is used as the aluminum material, it is durable, that is, resistant to alkali degreasing, against alkali treatment in the degreasing process. Furthermore, when a subsequent chemical conversion treatment such as zinc phosphate treatment is applied, a chemical conversion film is formed only on the steel material, and no chemical conversion film is formed on the coated aluminum material, eliminating the disadvantages of uneven chemical conversion treatment. It can be said to be a paint and coated aluminum material with high practical value, as it has good resistance to chemical conversion treatment and can prevent electrolytic corrosion of the aluminum material due to contact between different metals between the steel material and the coated aluminum material.

[0026]

[Examples] The present invention will be explained in more detail below with reference to Examples. In the examples, "parts" and "%" are expressed on a weight basis. (Preparation of epoxy resin solution (1)) In a three-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, 109.4 parts of bisphenol A, 64.0 parts of bisphenol F, and 6
A caustic soda aqueous solution prepared by dissolving 0 parts of caustic soda in 600 parts of water was added, and the mixture was heated at 50° C. for 10 minutes with stirring. Subsequently, 116 parts of epichlorohydrin was added and the temperature was gradually raised to 100° C. over 20 minutes, and this temperature was maintained for 40 minutes while stirring.

After cooling, the supernatant water layer was removed by the decanting method, and 600 parts of water was further added, heated to 90° C. and vigorously stirred. After cooling again, the supernatant water layer was removed in the same manner. Repeat this operation until it no longer shows alkalinity, and after thoroughly separating the water, heat to 150℃ with stirring.
The mixture was heated and dehydrated for 30 minutes to produce an epoxy resin having a molecular weight of about 900.

200 parts of the obtained epoxy resin was heated to 80°C to add 200 parts of ethylene glycol monoethyl ether.
Epoxy resin solution (1) with a solid content of 50% dissolved in
was prepared. (Preparation of epoxy resin solution (2)) Add 729.6 parts of bisphenol A, 160 parts of bisphenol F, and 2572 parts of a 10% caustic soda aqueous solution into a flask equipped with a stirrer, thermometer, and dropping funnel, and heat at 50°C for 10 minutes while stirring. Heated for minutes. Next, 463 parts of epichlorohydrin was added, heated to 100°C with stirring, and
It was held for 0 minutes.

Next, the supernatant water layer was removed by a decanting method, and the mixture was washed repeatedly with boiling water until it no longer showed alkalinity. Then, it was heated to 150° C. and dehydrated to produce an epoxy resin having a molecular weight of about 1400. 300 parts of the obtained epoxy resin was dissolved in 300 parts of ethylene glycol monobutyl ether heated to 80°C to prepare an epoxy resin solution (2) with a solid content of 50%. (Preparation of epoxy resin solution (3))
Epoxy equivalent obtained by adding 680 parts of ethylene glycol monoethyl ether acetate to a three-necked flask equipped with a reflux condenser, thermometer, and stirrer and heating it to 100°C, then reacting bisphenol A and epichlorohydrin. 1000 parts of 2800-3300 epoxy resin was added little by little and dissolved. Next, 25 parts of bisphenol F and 1 part of lithium chloride were added and reacted at 200°C for 60 minutes to prepare an epoxy resin solution (3) with a molecular weight of about 7000 and a solid content of 60%. (Modified epoxy resin solution (
4) Preparation) In a three-necked flask equipped with a reflux condenser, thermometer, and stirrer, 109.4 parts of bisphenol A, 64.0 parts of bisphenol F, and 60 parts of caustic soda were added.
An aqueous solution of caustic soda dissolved in 0 parts of water was added, and the mixture was heated at 50° C. for 10 minutes with stirring. Next, 116 parts of epichlorohydrin was added and the temperature was gradually raised to 100 parts in 20 minutes.
℃ and kept at this temperature for 40 minutes with stirring.

After cooling, the supernatant aqueous layer was removed by the decanting method, and 600 parts of water was further added, heated to 90° C., vigorously stirred, cooled again, and the supernatant aqueous layer was removed in the same manner. Repeat this operation until it no longer shows alkalinity.
Finally, after sufficiently separating water, heat at 150℃ while stirring.
The mixture was heated and dehydrated for 30 minutes to produce an epoxy resin having a molecular weight of about 900.

200 parts of ethylene glycol monoethyl ether obtained by heating 200 parts of the obtained epoxy resin to 80°C.
An epoxy resin solution with a solid content of 50% (4'
) was prepared. 180 parts of the epoxy resin solution (4') was heated to 60°C, then 17.7 parts of diethanolamine was added dropwise over 2 hours, and the reaction was further carried out at 70°C for 3 hours to form a modified epoxy resin solution with a solid content of 55%. (4) was prepared. (Preparation of modified epoxy resin solution (5)) Reflux condenser,
680 parts of ethylene glycol monoethyl ether acetate was added to a three-necked flask equipped with a thermometer and a stirrer, and after heating to 100°C, an epoxy equivalent of 28% was obtained by reacting bisphenol A and epichlorohydrin.
00-3300 epoxy resin was added little by little and dissolved. Next, 25 parts of bisphenol F and 1 part of lithium chloride were added and reacted at 200°C for 60 minutes to form an epoxy resin solution (5
') was prepared. The epoxy resin solution (5') 1167
7.5 parts of N-methylethanolamine was added to the solution and reacted in the same manner as the solution (4) above to prepare a modified epoxy resin solution (5) with a solid content of 60.2%. (Preparation of modified epoxy resin solution (6)) Bisphenol A109 was added to a three-necked flask equipped with a reflux condenser, a thermometer, and a stirrer.
．． 4 parts of bisphenol F, 64.0 parts of bisphenol F, and a caustic soda aqueous solution prepared by dissolving 60 parts of caustic soda in 600 parts of water were added, and the mixture was heated at 50° C. for 10 minutes with stirring. Next, 116 parts of epichlorohydrin was added and the temperature was gradually raised to 20 parts.
The temperature was raised to 100° C. for 40 minutes and maintained at this temperature for 40 minutes with stirring.

After cooling, the supernatant water layer was removed by the decanting method, and 600 parts of water was added, heated to 90°C, and vigorously stirred. After cooling again, the supernatant water layer was removed in the same manner. . Repeat this operation until it no longer shows alkalinity.Finally, after thoroughly separating the water, add water for 15 minutes while stirring.
The mixture was heated at 0° C. for 30 minutes and dehydrated to produce an epoxy resin having a molecular weight of about 900.

200 parts of ethylene glycol monoethyl ether obtained by heating 200 parts of the obtained epoxy resin to 80°C.
An epoxy resin solution (6'
) was prepared. 180 parts of the solution (6') was heated to 150°C, and 2 parts of hydroquinone and 1 part of dimethylbenzylamine were added.
and 26.6 parts of phthalic anhydride were added thereto and reacted for 5 hours to prepare a modified epoxy resin solution (6) with a solid content of 56%. (Preparation of modified epoxy resin solution (7)) Add 680 parts of ethylene glycol monoethyl ether acetate to a three-necked flask equipped with a reflux condenser, thermometer, and stirrer, and after heating to 100°C, add bisphenol A and epichlorohydrin. Epoxy equivalent 2 obtained by reacting with
1000 parts of 800-3300 epoxy resin was added little by little and dissolved. Next, 25 parts of bisphenol F and 1 part of lithium chloride were added and reacted at 200°C for 60 minutes.
Epoxy resin solution with a molecular weight of approximately 7000 and a solid content of 60% (
7′) was prepared.

4.5 parts of hydroquinone, 3.8 parts of dimethylbenzylamine and 14.6 parts of adipic acid were added to 1167 parts of the solution (7') and reacted in the same manner as in the solution (6) above to reduce the solid content. A 60.5% modified epoxy resin solution (7) was prepared. (Preparation of epoxy resin solution (8))
Bisphenol A type epoxy resin ["Epicote 100"
1” (trade name manufactured by Ciel Chemical Co., Ltd.), epoxy equivalent 450~
500] was dissolved in 300 parts of ethylene glycol monoethyl ether to prepare an epoxy resin solution (8) with a solid content of 50%. (Preparation of epoxy resin solution (9)) Bisphenol F type epoxy resin ["Epicron 83
0'' (trade name, manufactured by Dainippon Ink Chemical Industries, Ltd.), with an epoxy equivalent of about 175, was dissolved in 300 parts of ethylene glycol monoethyl ether to prepare an epoxy resin solution (9) with a solid content of 50%. Example 1 Epoxy resin solution (
1) 200 parts of polypropylene wax, 40 parts of polypropylene wax, and 497 parts of propylene glycol monoethyl ether were mixed to prepare a paint.

[0035] The obtained paint was applied to aluminum materials (thickness 1.0 mm) that had been subjected to various surface treatments as shown in Table 1, with a dry film thickness of 3 μm.
Roll coated so that the maximum board temperature is 3.
Baking at 150℃ in 0 seconds, corrosion resistance, moldability, alkali resistance, chemical conversion treatment resistance, electrodeposition coating properties, topcoat adhesion, water resistance, and paint stability tests were conducted, and the results are listed in Table 1. Shown in the column below. Examples 2 to 7 and Comparative Examples 1 to 4 A mixture of an epoxy resin solution and a lubricant powder in the proportions shown in Table 1 was diluted with propylene glycol monoethyl ether in an amount to give a solid content of 20%, and a paint was prepared. Prepared. The obtained paint was applied in the same manner as in Example 1, and various tests were conducted, and the results are shown in the lower column of Table 1.

As is clear from Table 1, in the Examples using the coating composition of the present invention, the coating stability was good;
It also had excellent coating film performance. On the other hand, in Comparative Example 1, which did not contain lubricant powder, moldability and the like were poor. Furthermore, in Comparative Example 2, which used an epoxy resin having a bisphenol skeleton and only a bisphenol A skeleton, moldability, electrodeposition coating properties, etc. were poor. Furthermore, in Comparative Example 3 in which an epoxy resin consisting only of bisphenol F skeleton was used as the bisphenol skeleton, corrosion resistance, alkali resistance, chemical conversion treatment resistance, water resistance, etc. were poor. Furthermore, in Comparative Example 4 using a liquid lubricant, electrodeposition coating properties, topcoat adhesion, water resistance, etc. were poor.

[0037]

[Table 1]

Note 1) “Shamrock Wax
S-363” (Shamrock Chemicals
(product name manufactured by Hoechst), average particle size 5 μm Note 2) “Ceridust 3910” (product name manufactured by Hoechst), average particle size 8 μm
Note 3) “Hitazol GP-60” (trade name manufactured by Hitachi Powder Metallurgy Co., Ltd.), average particle size 0.5 μm Note 4) “Rubron L
-2" (trade name manufactured by Daikin Industries, Ltd.), average particle size 5 μm Note 5) "Famex A-12" (trade name manufactured by Ajinomoto Co., Ltd.), average particle size 10 μm Note 6) "SC-100" (
Sakai Chemical Industry Co., Ltd. product name), average particle size 3 μm Note 7)
MD-40” (trade name manufactured by Hitachi Powder Metallurgy Co., Ltd.), average particle size 1
μm Note 8) “KF945(A)” (product name manufactured by Shin-Etsu Chemical Co., Ltd.), liquid Note 9) A cross cut was made on the coated surface of the test plate, and a salt spray test based on JIS-Z-2371 was conducted for 600 hours. Observe the rust occurrence ○: No abnormality at all △: White rust scattered ×: All white rust Note 10)
A test plate with a diameter of 50 mmφ and a depth of 25 mm was punched out with a diameter of 84 mmφ.
mm cylindrical drawing (BHF = 1 ton), and after processing JI
A salt water spray test was conducted for 400 hours based on S-Z-2371, and the occurrence of white rust was observed. ○: No white rust △:
White rust less than 5% ×: white rust 5% or more Note 11)
The test plate was immersed in an alkaline degreasing solution at 50°C, washed with water and dried, then cut 100 1mm gobs with a cutter knife, and measured the coating film remaining rate after the peel test using cellophane tape ◎: Immersion time 6 minutes Survival rate after: 100%
○: 〃 3 minutes 〃 100%△:
〃 〃 〃
90-99%×: 〃 〃 〃
89% or less Note 12) The test plate was immersed in a zinc phosphate treatment solution at 45°C for 3 minutes, and the coating film was observed after washing with water and drying ○: The coating film remained uniform as before chemical conversion treatment without peeling. Peeling of film Note 13) Apply amine-added epoxy resin-blocked isocyanate-based cationic electrodeposition paint to the coated surface of the test plate at a bath temperature of 28°C and 100V for 3 minutes, and bake at 165°C for 20 minutes. , Observe the appearance of the paint film (area 100 cm2) ○: Gas pins and craters generated 0 to 5 points △: Gas pins and craters generated 6 to 20 points
×: Gas pin and crater generation
20 points or more Note 14) Cut 100 1 mm goblets from the cationic electrodeposition coated plate obtained in Note 13).
- Make a cut with a knife, perform a peel test using cellophane tape, and measure the residual rate of the electrodeposition film. ○: 95-100%
△: 90-94% ×: 89% or less Note 15)
The cationic electrodeposition coated plate obtained in Note 13) was immersed in water at 40°C, dried, and then coated with Note 14.
) to measure the residual rate of the electrodeposited coating.

Claims (4)

[Claims] Claim 1: (i) Weight ratio of bisphenol A skeleton to bisphenol F skeleton (95:5 to 60:40
) and an epichlorohydrin skeleton, and has two or more epoxy groups in one molecule, and (ii
) A coating composition for aluminum materials containing lubricant powder having an average particle size of 0.1 to 20 μm. 2. Contains (i) a modified epoxy resin obtained by modifying the epoxy resin according to claim 1 with a basic nitrogen compound or a polybasic acid, and (ii) a lubricant powder with an average particle size of 0.1 to 20 μm. Coating composition for aluminum materials. 3. A coated aluminum material obtained by applying the coating composition according to claim (1) or claim (2) to the surface of an aluminum material that has been subjected to a base treatment. 4. The coated aluminum material according to claim 3, which is used for automobile bodies.