JPH07171500A - Coating film and fin with the same - Google Patents

Abstract

PURPOSE:To improve the wettability with water and workability of the coating film provided on a fin of the room air conditioner, etc., by using a layer like silicate mineral and a binder resin as the constituents of the coating film. CONSTITUTION:This coating film contg. a layer like silicate mineral and a binder resin is formed on a fin material used for heat exchangers such as the room air conditioner, etc., to improve the press-formability, properties with respect to mold wear and wettability with water of the fin material and also to solue the problem of generating an odor in the initial stage of cooling. At this time, flat-platelike particles formed by the inter layer peeling of the layer like silicate mineral are preferably three-dimensionally dispersed into the binder resin and the weight ratio of the layer like silicate mineral to the binder resin is regulated to 2:98 to 60:40. As the layer like silicate mineral, that contg. synthetic mica or synthetic smectite having 0.5 to 100mum average particle size is used. As the binder resin, that contg. a (meth)acrylate-based copolymer is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film having excellent wettability and workability, and particularly to a fin provided with a coating film having excellent wettability and workability.

[0002]

BACKGROUND OF THE INVENTION Recently, room air conditioners have rapidly spread with the improvement of living standards, and the demand for fin materials for heat exchangers is extremely high. As the fin material, aluminum or aluminum alloy (simply aluminum) which is excellent in lightness, workability, and thermal conductivity is widely used.

The fins incorporated in the heat exchanger are coated with water glass or the like on the surface of the aluminum material for the purpose of improving the heat exchange efficiency, that is, in order to improve the water wettability of the fins. Is proposed. However, with the technical means for coating water glass proposed in, for example, Japanese Patent Application Laid-Open No. 58-126989 and Japanese Patent Publication No. 55-1347, water glass gradually melts, so that it is possible to maintain wetness. There is a problem with sex.
In addition, there is a problem that the water glass adsorbs odorous components in the environment and produces odors in the early stage of cooling operation. Furthermore, since the water glass film is hard, when the fins are manufactured by continuously molding after forming the water glass film (precoat treatment),
The mold wear is significant and the cost is high.

Further, a technical means for coating a mixture of an organic resin with water glass, silica or the like, which is proposed in JP-B-62-61078 and JP-A-61-225044, and JP-A-59-170170. In the technical means of applying a coating composed of an organic resin-silica composite proposed in Japanese Patent Publication, although the problem of persistence of water wetting is improved, the problem of odor at the beginning of cooling operation and the mold There is still a problem that the wear is remarkable.

Further, in the technical means of coating a mixture of organic resin and organic fine particles, which is proposed in JP-A-62-129366 and JP-A-63-372, the mold abrasion and the odor are caused. However, the problem of water wettability remains. Also, the fins are washed with a halogen-based solvent after press molding,
Recently, due to environmental problems such as ozone depletion and water pollution, regulations on the use of halogenated solvents such as CFCs and trichlorethylene have been tightened. In order to deal with such a situation, the use of volatile press oil, which does not require solvent cleaning, has started to be used.However, volatile press oil has a lower viscosity than conventional oils, and it is easy to press workability and die wear. The problem is growing.

[0006]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a technique having improved press workability, mold abrasion property, odor problem in the early stage of cooling, and wettability. The object of the present invention is achieved by a coating film containing a layered silicate mineral and a binder resin.

In particular, it is achieved by a coating film characterized in that delaminated tabular grains of a layered silicate mineral are three-dimensionally dispersed in a binder resin. Further, it is achieved by a fin characterized in that a coating film containing a layered silicate mineral and a binder resin is provided on the surface of a fin made of aluminum or an aluminum alloy.

[0008] In particular, it is characterized in that a coating film comprising three-dimensionally dispersed tabular grains of a layered silicate mineral dispersed in a binder resin is provided on the surface of a fin made of aluminum or an aluminum alloy. Achieved by Fins. Further, the present invention is achieved by a fin characterized in that a coating film containing a layered silicate mineral and a binder resin is provided on the surface of an aluminum or aluminum alloy material and then formed and processed.

In particular, a coating film comprising three-dimensionally dispersed tabular grains of a layered silicate mineral dispersed in a binder resin is provided on the surface of an aluminum or aluminum alloy material and then molded. It is achieved by the fin characterized by being. In the above invention, the ratio of the layered silicate mineral to the binder resin is 2 to 98 to 60:40.
(Weight ratio) is preferable. More preferably 10
90 to 30 to 70 (weight ratio).

The layered silicate mineral is preferably one containing mica, particularly synthetic mica. This synthetic mica has an average particle size of 0.5 to 100 μm, preferably 1 to 10 μm. Also, the thickness of each layer is 30 due to delamination.
A synthetic mica of about 0 to 400Å is preferable. The layered silicate mineral is preferably one containing smectite, particularly synthetic smectite (for example, synthetic bentonite or synthetic hectorite). This synthetic smectite has an average particle size of 1 to 10 μm, preferably 1 to 3 μm. Also, the thickness of each layer is 1 to 5 due to delamination.
A synthetic smectite of about 0Å is preferable.

The synthetic mica and the synthetic smectite are preferably used in combination, and the mixing ratio thereof is preferably 99: 1 to 40: 60 (weight ratio). More preferably, it is 90:10 to 70:30 (weight ratio).
As the binder resin, a (meth) acrylic acid ester-based copolymer constituted by using a (meth) acrylic acid ester, particularly an unsaturated monobasic acid other than the (meth) acrylic acid ester and the (meth) acrylic acid ester ( The ratio of the (meth) acrylic acid ester and the unsaturated monobasic acid is preferably 99.5: 0.5 to 95: 5 (molar ratio)), and the (meth) acrylic acid ester-based copolymer Those containing coalescence are preferred. The degree of polymerization of such a (meth) acrylic acid ester-based copolymer is preferably 10,000 to 100,000.

Examples of the (meth) acrylic acid ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate and iso-.
Propyl acrylate, iso-propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, iso-butyl acrylate, iso-butyl methacrylate, tert-butyl acrylate, tert
-Butyl methacrylate, pentyl acrylate, pentyl methacrylate, neopentyl acrylate, neopentyl methacrylate, hexyl acrylate, hexyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate,
Lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-
Hydroxypropyl methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxystyrene acrylate, 2-hydroxystyrene methacrylate, diethylene glycol monoacrylate, diethylene glycol mono Acrylic alkyl esters and methacrylic acid alkyl esters such as methacrylate, triethylene glycol monoacrylate, and triethylene glycol monomethacrylate (for example, C _{1 to} C
Ester of ₁₂ monohydric or polyhydric alcohol and acrylic acid or methacrylic acid), 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl acrylate, 2 -Butoxyethyl methacrylate, 3-methoxypropyl acrylate, 3-methoxypropyl methacrylate, 3-ethoxypropyl acrylate, 3-ethoxypropyl methacrylate, 2-methoxypropyl acrylate, 2-methoxypropyl methacrylate, 2-ethoxypropyl acrylate, 2-ethoxy Propyl methacrylate,
Examples thereof include acrylic acid alkoxyalkyl esters such as phenoxyethyl acrylate and phenoxyethyl methacrylate, and methacrylic acid alkoxyalkyl esters.

Further, a part of the above-mentioned esters selected from the group of acrylic acid esters and methacrylic acid esters may be substituted with monomers similar thereto. For example, phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, glycidyl acrylate, glycidyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, acrylamide, methacrylamide, N-
Methylol acrylamide, N-alkyl acrylamide, N, N-dialkyl acrylamide, N-alkyl methacrylamide, N, N-dialkyl methacrylamide, morpholino acrylate, morpholino methacrylate, morpholino ethyl acrylate, morpholino ethyl methacrylate, aminoalkyl acrylate, aminoalkyl methacrylate , N-alkylaminoalkyl acrylate, N, N-dialkylaminoalkyl acrylate, N-alkylaminoalkyl methacrylate, N, N-dialkylaminoalkyl methacrylate, fumaric acid monoester, fumaric acid diester, maleic acid monoester such as butyl maleate Substitute with ester, maleic acid diester, itaconic acid monoester, itaconic acid diester, etc. It can be.

Examples of unsaturated monobasic acids include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, cinnamic acid, maleic anhydride, itaconic acid, sorbic acid, hydroxyethyl methacrylate maleate, hydroxyethyl acrylate maleate and hydroxy. Examples thereof include propyl methacrylate maleate, hydroxypropyl acrylate maleate, dicyclopentadiene maleate and the like.

In addition, styrene, vinyltoluene, acrylonitrile, aziridinyl methacrylate, etc. can be used. Further, for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate,
Tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, trimethylolpropane tri Acrylate, trimethylolpropane trimethacrylate,
Polyfunctional acrylic acid esters and polyfunctional methacrylic acid esters such as 1,6-hexanediol diacrylate and 1,6-hexanediol dimethacrylate, vinyl acrylate, vinyl methacrylate, divinylbenzene,
Polyfunctional vinyl compounds such as N, N′-divinylbislactam, allyl acrylate, allyl methacrylate, diallyl itaconate, monoallyl itaconate, diallyl succinate, diallyl adipate, triallyl cyanurate, triallyl isocyanurate, etc. Polyfunctional allyl compound, allyloxyethyl acrylate, allyloxyethyl methacrylate, diaryloxyethyl itaconate, monoallyloxyethyl itaconate, 3-butenoic acid methacryloyloxyethyl ester, 2
-Butenoic acid methacryloyloxyethyl ester, pentaerythritol tetra (3-butenate), pentaerythritol tetra (crotonate),
1,3,5-tri (3-butenoic acid) phenyl ester, 1,3,5-tri (2-butenoic acid) phenyl ester, tri (3-butenoyloxyethyl) isocyanurate, tri (2-butenoyloxyethyl) isocyanurate, [2- (1'-methacryloyloxyethyl) -4-allyl] -N, N-tolylenecarbamate, 4-allyl-2- (N-methacryloylaminotri) Yl) -N'-carbamate, 2,4-diallyl-N, N'-tolylenebiscarbamate, [2-
Allyl-4- (1'-methacryloyloxyethyl)]
-N, N'-tolylene carbamate, 2-allyl-4-
(N-methacryloylaminotriyl) -N'-carbamate, 2,4- (1 ', 1''-dimethacryloyloxyethyl) -N, N'-tolylenebiscarbamate,
A cross-linking agent such as 1,3,5-triallyl-N, N ′, N ″ -benzenetriscarbamate can be used if necessary.

The binder resin preferably contains a polyethylene glycol-based polymer (preferably a polymer obtained by polymerizing polyethylene glycol with a dibasic crosslinking agent). The polyethylene glycol-based polymer preferably has a degree of polymerization of 100,000 to 150,000. It is particularly preferable to use the (meth) acrylic acid ester-based copolymer and the polyethylene glycol-based polymer in combination, and in such a case, the (meth) acrylic acid ester-based copolymer and the polyethylene glycol-based polymer are used. The mixing ratio with is preferably 90:10 to 10:90 (weight ratio). It is more preferably 30:70 to 50:50 (weight ratio).

Incidentally, a part of the polyethylene glycol type polymer may be substituted with polyvinyl alcohol, polyethylene oxide, hydroxypropyl cellulose, pullulan, methyl cellulose or the like. Then, in a state in which the synthetic mica or synthetic smectite as described above is dissolved and dispersed in an aqueous solution, these layered silicate minerals are delaminated, and tabular grains consisting of one layer are three-dimensionally It's as if they were dispersed. An aqueous solution containing a binder resin in which such tabular particles are three-dimensionally dispersed is applied to the surface of the aluminum material by an appropriate application means such as spraying, roll coating, shower coating, and dipping. The coating thickness is 0.1 to 5μ after drying.
m (desirably 0.5 to 2 μm) is preferable. Then, it is dried under conditions of a temperature of 100 to 260 ° C. and a time of about 3 to 180 seconds.

After that, by performing press working such as drawless press working or draw press working to form the fin, the die is less likely to be worn, the press is performed with good workability, and the odor in the early stage of cooling is improved. The problem described above is greatly improved, and a fin having improved wettability can be obtained.
Before providing the coating film according to the present invention, after degreasing the aluminum material, boehmite treatment, chromate treatment, phosphoric acid chromate treatment, zirconate treatment, or corrosion-resistant organic resin (epoxy resin type, urethane resin type, phenol resin type) It is preferable to perform a coating treatment of (1) and the like to provide a corrosion resistant film.

[0019]

【Example】

[Example 1] 48.8 parts by weight of tap water, 2.9 parts by weight of synthetic mica (average particle size: 1.15 µm, thickness per layer when delaminated is about 300 to 400Å), and synthetic smectite ( With an average particle diameter of 1 μm, the thickness per layer when delaminated is about 10 to 20Å) 0.6 parts by weight and a polyethylene glycol polymer (polymerization degree 120,000) 6.5 parts by weight by means of a high speed disperser. Dispersed well.

After leaving this mixed and dispersed aqueous solution for 24 hours, 11.8 parts by weight of methanol and 29.4 parts by weight of tap water were added and thoroughly mixed and dispersed. To 100 parts by weight of this mixed dispersion aqueous solution (mixed dispersion aqueous solution of Example 1), a copolymer (2-hydroxyethyl methacrylate: acrylic acid: acrylic acid: 2-hydroxyethyl methacrylate, acrylic acid and N-methylol acrylamide) was added.
5 parts by weight of an aqueous solution (solid content: 14.7%) of N-methylolacrylamide = 95: 4: 1 and a degree of polymerization of 90,000 was slowly added and mixed sufficiently to obtain a coating composition.

Example 2 A copolymer (2-hydroxyethyl methacrylate: 2-hydroxyethyl methacrylate: acrylic acid and N-methylol acrylamide) was added to 100 parts by weight of the aqueous mixed dispersion solution obtained in Example 1.
Acrylic acid: N-methylol acrylamide = 95:
4: 1, polymerization degree 90,000) aqueous solution (solid content 14.7%) 1
A coating composition was obtained by slowly adding 0 parts by weight and thoroughly mixing.

Example 3 A copolymer (2-hydroxyethyl methacrylate: 2-hydroxyethyl methacrylate: acrylic acid, and N-methylolacrylamide) was added to 100 parts by weight of the mixed dispersion aqueous solution obtained in Example 1.
Acrylic acid: N-methylol acrylamide = 95:
4: 1, polymerization degree 90,000) aqueous solution (solid content 14.7%) 1
5 parts by weight were added slowly and mixed well to obtain a coating composition.

Example 4 100 parts by weight of the mixed dispersion aqueous solution obtained in Example 1 was mixed with a copolymer of 2-hydroxyethyl methacrylate, acrylic acid and N-methylol acrylamide (2-hydroxyethyl methacrylate:
Acrylic acid: N-methylol acrylamide = 95:
4: 1, polymerization degree 90,000) aqueous solution (solid content 14.7%) 2
A coating composition was obtained by slowly adding 0 parts by weight and thoroughly mixing.

Example 5 100 parts by weight of the aqueous mixed dispersion solution obtained in Example 1 was mixed with a copolymer of 2-hydroxyethyl methacrylate, acrylic acid and N-methylolacrylamide (2-hydroxyethyl methacrylate:
Acrylic acid: N-methylol acrylamide = 95:
4: 1, polymerization degree 90,000) aqueous solution (solid content 14.7%) 3
A coating composition was obtained by slowly adding 0 parts by weight and thoroughly mixing.

Example 6 100 parts by weight of the aqueous mixed dispersion solution obtained in Example 1 was mixed with a copolymer of 2-hydroxyethyl methacrylate, acrylic acid and N-methylolacrylamide (2-hydroxyethyl methacrylate:
Acrylic acid: N-methylol acrylamide = 95:
4: 1, polymerization degree 90,000) aqueous solution (solid content 14.7%) 5
A coating composition was obtained by slowly adding 0 parts by weight and thoroughly mixing.

Example 7 100 parts by weight of the mixed dispersion aqueous solution obtained in Example 1 was mixed with synthetic mica (average particle size: 1.15 μm,
When delaminated, the thickness per layer is 300-400
Å) 2.4 parts by weight to disperse and stabilize, then
An aqueous solution of a copolymer consisting of hydroxyethyl methacrylate, acrylic acid and N-methylol acrylamide (2-hydroxyethyl methacrylate: acrylic acid: N-methylol acrylamide = 95: 4: 1, degree of polymerization 90,000) (solid content: 14. 50% by weight (7%) was gently added and mixed well to obtain a coating composition.

Example 8 100 parts by weight of the mixed dispersion aqueous solution obtained in Example 1 was mixed with synthetic mica (average particle size: 1.15 μm,
When delaminated, the thickness per layer is 300-400
1 part by weight of about Å) to disperse and stabilize, and then a copolymer consisting of 2-hydroxyethyl methacrylate, acrylic acid and N-methylol acrylamide (2-hydroxyethyl methacrylate: acrylic acid: N-methylol acrylamide = 95) : 4: 1, degree of polymerization 90,000) 20 parts by weight of an aqueous solution (solid content 14.7%) was slowly added and mixed sufficiently to obtain a coating composition.

[Comparative Example 1] 48.8 parts by weight of clean water, 3.5 parts by weight of water-dispersed aggregated colloidal silica (particle size: 0.2 μm), and a polyethylene glycol polymer (polymerization degree: 120,000)
6.5 parts by weight were sufficiently dispersed with a high-speed disperser.
After leaving this mixed and dispersed aqueous solution for 24 hours, 11.8 parts by weight of methanol and 29.4 parts by weight of tap water were added and sufficiently mixed and dispersed.

To 100 parts by weight of this mixed dispersion aqueous solution, 2-
An aqueous solution of a copolymer consisting of hydroxyethyl methacrylate, acrylic acid and N-methylol acrylamide (2-hydroxyethyl methacrylate: acrylic acid: N-methylol acrylamide = 95: 4: 1, degree of polymerization 90,000) (solid content: 14. 5% by weight (7%) was gently added and thoroughly mixed to obtain a coating composition.

Comparative Example 2 91 parts by weight of tap water, 3 parts by weight of polyacrylic acid, and 0.1 part by weight of polyoxyethylene alkylphenyl ether were thoroughly mixed, and 6 parts by weight of sodium silicate No. 3 was added thereto. Parts were gently added and mixed well to obtain a coating composition. [Comparative Example 3] 84 parts by weight of tap water, 15 parts by weight of thermosetting polyester, 1 part by weight of methylated melamine, and 1 part by weight of polyalkylene oxide-modified silicon were sufficiently mixed to obtain a coating composition. .

[Characteristics] An aluminum plate (JIS A1100) obtained by subjecting the coating composition of each of the above examples to a phosphoric acid chromate treatment.
The thickness after drying is 1μ.
The roll coating was performed so that the thickness became m, and baking was performed at 240 ° C. for 20 seconds. Then, this aluminum plate was formed into a fin by drawless press processing.

The fins thus obtained were incorporated into a heat exchanger through predetermined steps and the characteristics of the fins were examined. The results are shown in Table-1. Table-1 Hydrophilic persistence, coating adhesion, paint stability, mold abrasion, odor in the early stage of cooling Example 1 ○ ○ ○ ○ ○ Example 2 ○ ○ ○ ○ ○ Example 3 ○ ○ ○ ○ ○ Example 4 ○ ○ ○ ○ ○ Example 5 ○ ○ ○ ○ ○ Example 6 ○ ○ ○ ○ ○ Example 7 ○ ○ ○ ○ ○ Example 8 ○ ○ ○ ○ ○ Comparative Example 1 ○ − △ × △ Comparative Example 2 ○ − × × × Comparative Example 3 × − ○ ○ ○ * Hydrophilicity persistence: The coated plate was washed with water for 8 hours and dried at 80 ° C. 1
One cycle consists of 6 hours and 15 cycles are processed to measure the contact angle of water droplets.

○ Contact angle 30 ° or less △ Contact angle 31 to 50 ° × Contact angle 51 ° or more * Coating film adhesion: Rub the coated plate surface 10 times with a felt under a load of 5 kg, and observe the appearance.

○ No film peeling △ Very partial film peeling × Film peeling * Paint stability: The coating composition was allowed to stand in a constant temperature bath at 50 ° C for 2 weeks, and Judgment.

○ Almost no change from the initial state of production △ Slight separation, sedimentation × Separation, sedimentation ＊ Die abrasion resistance: The coated coil was subjected to drawless processing using volatile press oil (RF190 manufactured by Showa Shell Sekiyu) 1
After performing a stamping process of 100,000 strokes, observe the scratches and wear of the ironing punch.

○ Punch scratches, no wear △ Slight scratches, wear × Scratches, wear

[0037]

[Effect] A fin having improved press workability, mold wearability, odor problem in the early stage of cooling, and water wettability can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Itaya 4-14-7-405 Sennan Tainan, Wakaba-ku, Chiba-shi, Chiba (72) Inventor Hitoshi Satake 3-47, Shioiri-cho, Yokosuka-shi, Kanagawa (72) Invention Person Kouji Hayashiga 738-1 Endo, Fujisawa City, Kanagawa Prefecture (72) Inventor Tomoyuki Ishii 2-30, Omagari, Samukawa Town, Takaza District, Kanagawa Prefecture

Claims (19)

[Claims] 1. A coating film comprising a layered silicate mineral and a binder resin. 2. A coating film comprising three-dimensionally dispersed tabular grains of a layered silicate mineral dispersed in a binder resin. 3. The coating film according to claim 1, wherein the ratio of the layered silicate mineral and the binder resin is 2 to 98 to 60:40 (weight ratio). 4. The coating film according to claim 1, wherein the layered silicate mineral contains a synthetic mica. 5. The layered silicate mineral has an average particle size of 0.5 to 1.
The coating film according to any one of claims 1 to 3, which contains a synthetic mica of 00 µm. 6. The coating film according to claim 1, wherein the layered silicate mineral contains a synthetic smectite. 7. The layered silicate mineral has an average particle size of 1 to 10 μm.
The coating film according to any one of claims 1 to 3, which contains m of synthetic smectite. 8. The coating film according to claim 1, wherein the layered silicate mineral contains a mixture of synthetic mica and synthetic smectite. 9. The layered silicate mineral has an average particle size of 0.5 to 1.
The coating film according to any one of claims 1 to 3, comprising a mixture of 00 m of synthetic mica and synthetic smectite having an average particle size of 1 to 10 m. 10. The coating film according to claim 8 or 9, wherein the mixing ratio of the synthetic mica and the synthetic smectite is 99: 1 to 40:60 (weight ratio). 11. The binder resin contains a (meth) acrylic acid ester-based copolymer constituted by using a (meth) acrylic acid ester.
~ The coating film according to claim 3. 12. The binder resin is composed of (meth) acrylic acid ester and unsaturated monobasic acid (meth).
The coating film according to any one of claims 1 to 3, which comprises an acrylic acid ester-based copolymer. 13. The binder resin contains a polyethylene glycol-based polymer.
~ The coating film according to claim 3. 14. The binder resin contains a mixture of a (meth) acrylic acid ester-based copolymer and a polyethylene glycol-based polymer.
The coating film according to claim 3. 15. The mixing ratio of the (meth) acrylic acid ester-based copolymer and the polyethylene glycol-based polymer is 9
The coating film according to claim 14, which has a weight ratio of 0:10 to 10:90. 16. A fin, wherein the coating film according to any one of claims 1 to 15 is provided on the surface of a fin made of aluminum or an aluminum alloy. 17. After the coating film according to claim 1 is provided on the surface of an aluminum or aluminum alloy material,
A fin characterized by being formed. 18. The fin according to claim 16 or 17, wherein the coating film formed on the surface has a thickness of 0.1 to 5 μm. 19. A corrosion-resistant film is provided as a base of a coating film provided on the surface.
Or the fin of claim 17.