JPH02219877A - Hydrophilic coating agent, aluminum or aluminum alloy sheet for fin and heat exchanger - Google Patents

Abstract

PURPOSE:To obtain the title coating agent providing a coating film with excellent wettability and excellent adhesion with Al material by polymerizing a plurality of specified alpha,beta-unsatd. monomers. CONSTITUTION:An alpha,beta-unsatd. monomer with a sulfonic acid group (e.g. 2- acrylamido-2-methylpropanesulfonic acid), an alpha,beta-unsatd. monomer with a hydroxyl group (e.g. 2-hydroxyethyl acrylate), an alpha,beta-unsatd. monomer with a carboxyl group (e.g. methacrylic acid) and an alpha,beta-unsatd. monomer with a (methylol)amide group (e.g. N-methylolacrylamide) are polymerized together.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a coating method for forming a hydrophilic film on the surface of a metal, particularly an aluminum material or an aluminum alloy material (hereinafter simply referred to as an aluminum alloy material). The present invention relates to a composition made of aluminum alloy, an aluminum alloy plate prepared by thermosetting the composition, and a heat exchanger coated with the same.

[Prior Art] Since the surface of a metal material is poor in hydrophilicity, the fins of a heat exchanger and the planographic printing plate material for printing are coated with a hydrophilic film. Hereinafter, in this specification, the case of the fins of a heat exchanger will be described using an air conditioner as an example.

Recent heat exchangers for air conditioners are required to have improved thermal efficiency and be more compact in order to reduce weight, and designs have been adopted in which the spacing between fins is made as narrow as possible. In heat exchangers for air conditioners, moisture in the air becomes condensed water and adheres to the surface of aluminum fins during cooling operation. The surface of the metal material is
- Since hydrophilicity is generally poor, this condensed water exists on the fin surface in a semicircular shape or in the form of a bridge between the fins, as shown in FIG.

This obstructs the flow of air between the fins, increases ventilation resistance, and causes a significant decrease in heat exchange efficiency.

To improve the thermal efficiency of the heat exchanger, it is necessary to quickly eliminate condensed water on the fin surface. As a solution to this problem, (1) a highly hydrophilic film is formed on the surface of the aluminum alloy fin, allowing the condensed water to flow down as a thin water film; (2) a water-repellent film is formed on the surface of the aluminum alloy fin, and the condensed water is directed to the surface. Although it is possible to prevent the adhesion, method (2) is currently extremely difficult.

In order to obtain hydrophilic properties, a coating film is applied to the surface, and the composition of the hydrophilic film prevents the formation of condensed water droplets on the surface of the material and maintains the water film on the surface of the material. is used for.

Therefore, various methods for forming hydrophilic films have been proposed and put into practice. For example, a method of forming an alkali silicate film on the surface of an aluminum fin (Japanese Patent Publication No. 53
-48177), a method of applying a composition containing a water-based paint resin, a surfactant, and synthetic silica to form a hydrophilic film (Japanese Patent Application Laid-Open No. 184284/1984), A method of forming a hydrophilic film by coating a composition containing a low-molecular organic compound and a water-soluble organic polymer compound (Japanese Unexamined Patent Publication No. 130-10
No. 1158) has been proposed.

[Problems to be Solved by the Invention] However, the method of forming an alkali silicate film in order to impart hydrophilicity has a drawback that the hydrophilicity does not last long over time, and that it When made into fins, the hardness of the coating is high, which increases wear on the mold and tends to cause cracks in the coating when formed into fins.

In those containing a surfactant, it is impossible to prevent the bleeding phenomenon because the surfactant basically migrates toward the surface of the film. As a result, the hydrophilicity of the fin surface decreases over time. Also, since it contains synthetic silica, when it is applied to a material and processed into fins, it acts like an abrasive and increases wear on the mold. The method of forming a hydrophilic film by applying a composition containing a low-molecular organic compound having an alkali silicate and a carbonyl compound and a water-soluble organic polymer compound has been improved in terms of sustainability of hydrophilicity. In order to expect sufficient wettability of the film, the content of alkali silicate must be high. Increase wear.

Therefore, an object of the present invention is to provide a film composition that has good adhesion to aluminum and excellent film physical properties, has no change in hydrophilicity over time, and has good wettability to water. It is an object of the present invention to provide a coating agent that forms a hydrophilic film that does not cause significant wear on a mold when it is applied and processed.

[Means for Solving the Problems] The present inventors have conducted repeated research to solve the above problems. In order for the coating on an aluminum plate to be sufficiently wetted by water, the coating itself needs to have excellent hydrophilic properties, but this depends on the mechanical properties such as the toughness of the coating itself and the adhesion. It was found that it is important to achieve both of these two properties.

Therefore, as a result of further research, it was found that by selecting a combination of constituent monomers of the polymer that forms the coating material, it was possible to achieve both the above-mentioned contradictory properties, that is, the wettability of the formed film and other properties. They discovered that it is possible to do this, and completed the present invention.

The gist of the present invention is that A, an α,β unsaturated monomer having a sulfonic acid group, and an α,β unsaturated monomer having a B hydroxyl group.
Hydrophilicity obtained by polymerizing an unsaturated monomer, an α,β unsaturated monomer having a C carboxyl group, an α,β unsaturated monomer having a D amide group and/or a methylolamide group The first invention is a coating agent, and includes an α,β unsaturated monomer having A sulfonic acid, B an α2 β unsaturated LliQ body having a hydroxy group, and an α,β unsaturated monomer having a C carboxyl group. , a hydrophilic coating obtained by polymerizing an α,β unsaturated monomer having a D amide group and/or a methylolamide group, and a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent. The second invention provides a thermosetting hydrophilic coating agent comprising at least one curing agent selected from A, an α,β unsaturated monomer having a sulfonic acid group, and B an α,β unsaturated monomer having a hydroxyl group. A hydrophilic coating material obtained by polymerizing an unsaturated monomer, an αβ unsaturated monomer having a C carboxyl group, and an α,β unsaturated monomer having a D amide group and/or a methylolamide group. and at least one type of curing agent selected from the group consisting of a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent, is applied to an aluminum or aluminum alloy plate material and thermosetted. The third invention is an aluminum or aluminum alloy plate material for fins, which has A an α, β unsaturated monomer having a sulfonic acid group, B an α, β unsaturated monomer having a hydroxy group, and a C carboxyl group. A hydrophilic coating material and a methylol curing agent obtained by polymerizing an αβ unsaturated monomer, an α,β unsaturated monomer having a D amide group and/or a methylolamide group,
A heat exchanger comprising a hydrophilic thermosetting coating formed on the surface of an aluminum or aluminum alloy fin, which is formed from at least 11-1 curing agent selected from the group consisting of an etherified methylol curing agent and a polyepoxide curing agent. The fourth invention is a container.

The monomers used in the production of the polymer constituting the hydrophilic coating material of the present invention will be explained.

The α, β unsaturated monomer component having a sulfonic acid group of component A has strong anionic water properties and functions to make the polymer water-soluble. Improves wettability. Examples of this component A include 2-acrylamide-2-methylpropanesulfonic acid, vinylsulfonic acid, and stylinonesulfonic acid, but in particular 2-acrylamide-2-
Methylpropanesulfonic acid is preferred.

In addition, the α, β unsaturated monomer component having a hydroxyl group in component B causes a crosslinking reaction with the curing agent component, and improves the physical and chemical properties of the film, such as adhesion to the aluminum plate, toughness, and flexibility. Forms a thermosetting resin with excellent properties. This B component is, for example, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate represented by the following structural formula? R ring 11. Examples include CL R-H, CIl, etc., especially 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (
Meth)acrylates are preferred.

The α,β unsaturated monomer component having a carboxyl group, component C, causes a crosslinking reaction with the curing agent component.

In addition, α, β having a methylol group or an etherified methylol group as a curing agent component and a hydroxy group as a component B
It not only promotes the condensation reaction with the unsaturated monomer, but also contributes to the reaction with component B. Further, even when this component forms a salt with a volatile base such as ammonia, carboxyl groups are liberated during baking, which acts as an anchor effect to the aluminum plate and improves adhesion. Examples of this C component include (meth)acrylic acid, maleic anhydride, crotonic acid, itaconic acid, fumaric acid, maleic acid, fumaric acid, and itaconic acid half ester, among which acrylic acid, methacrylic acid, and Acids are particularly preferred.

The α,β unsaturated monomer having an amide group and/or methylolamide group of component D serves as a crosslinking point with the curing agent together with component C. It also functions to impart flexibility to the film. Examples of such components include (meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-methyl(meth)acrylamide, N- Examples include ethyl (meth)acrylamide, among which (meth)acrylamide, N
-Methylol (meth)acrylamide and N-methoxymethyl (meth)acrylamide are particularly preferred.

The polymerization of these components A, B, C, and D is carried out by radical polymerization in an aqueous medium. Copolymer (7) 4n composition ratio A/B/C/DfJ (ffIffi% 20-70/l
The range of O to GO15 to Q515 to 40 is preferable.

As the polymerization initiator, those generally used in the polymerization of vinyl monomers can be used, but water-soluble ammonium persulfate and potassium persulfate are particularly preferred, and these can be used alone or in combination with sodium metabisulfite or sodium thiosulfate. The polymerization may be carried out using a sodium redox system using a combination of the following, or an oil-soluble initiator such as azobisisobutyronitrile may be dissolved in a small amount of alcohol and finely dispersed in the polymerization system. The radical polymerization initiator is O91-5! relative to the monomer. It is preferable to use rI amount%.

The polymerization temperature is preferably 20 to 40°C in the case of 1-nodox type, and 60 to 80°C in other cases.

Moreover, the monomer concentration in the aqueous medium is preferably 10 to 30%. A water-soluble organic solvent is used as the polymerization regulator. Such an organic solvent and 1. Examples include lower alcohols such as methanol, ethanol, and impropatol, monoalkyl ethers of glycols such as ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, and others such as acetone and dioxane.

The hydrophilic resin thus obtained contains a sulfonic acid group and a carboxyl group in its polymer chain, and the sulfonic acid group is partially or completely contained within the range where the resin sufficiently exhibits hydrophilicity. However, some or all of the carboxyl groups are also neutralized. This neutralization can be done at any time,
That is, it can be carried out at any time, that is, it can be carried out after polymerization, or it can be carried out in the monomer state before polymerization.

As a neutralizing agent, sodium hydroxide for component A;
It is preferable to use an alkali metal hydroxide such as potassium hydroxide, and for component C, it is preferable to use aqueous ammonia or a volatile organic amine.

As the curing agent, those having a functional group that causes a crosslinking reaction with the hydroxy group or carboxyl group in the hydrophilic resin can be used, but in the present invention, a methylol curing agent,
At least 1 tJ of curing agent selected from the group consisting of etherified methylol curing agents and polyepoxide curing agents is used. By selecting the curing agent, a film having excellent mechanical properties, adhesion, and hydrophilicity can be formed.

Examples of the methylol curing agent in the present invention include N-methylol compounds such as dimethylol urea, trimethylol melamine, hexamethylol melamine, monomethylol thiourea, dimethylol urea, and dimethylol ethylene urea.

Among these, dimethylol urea, trimethylol melamine, and hexamethylol melamine are particularly preferred.

In addition, as the etherified methylol curing agent, dimethoxymethylurea, trimethoxymethylmelamine, hexamethoxymethylmelamine, monomethoxymethylthiourea,
Examples include dimethoxymethylthiourea, dimethoxymethylethyleneurea, and among these, dimethoxymethylurea, trimethoxymethylmelamine, and hexamethoxymethylmelamine are particularly preferred.

Among the polyepoxide curing agents of the present invention, glycidyl ether type polyepoxides of polyhydric alcohols are particularly preferred.

Specific examples of such epoxy resins include (1) polyethylene glycol diglycidyl ether, (2) polypropylene glycol diglycidyl ether, (3) polyglycerol polyglycidyl ether, (4)
) glycerol polyglycidyl ether (5) hydantoin diglycidyl, and the like.

The amount of the curing agent used varies depending on the amount of functional groups in the resin and the functional groups in the curing agent, but is used in the range of 0.1 to eo weight % based on the hydrophilic resin (10% concentration).

A curing catalyst can further be used in the hydrophilic coating of the present invention. Examples of curing catalysts that can be used in the present invention include: (1) ammonium salts of inorganic acids such as ammonium chloride, ammonium nitrate, and diammonium phosphate; (2) inorganic metal salts such as magnesium chloride, zinc nitrate, and magnesium dihydrogen phosphate; organic acid ammonium salts such as acid ammonium salts and citrate ammonium salts; ■ 2-amino-2-methyl-1-propatur hydrochloride and phosphate; ■ para-toluenesulfonic acid ammonium salts, benzenesulfonic acid ammonium salts, etc. Organic sulfonates, etc. can be mentioned.

In use, the above accelerators can be used alone or in combination. However, the curing catalyst depends on the temperature and time during thermal curing, or the curing agent. It is also greatly influenced by strong basic curing agents such as methylolmelamine, or
When curing conditions at temperatures above 0°C are adopted,
Generally, a curing catalyst is not necessary, and if used, it causes deterioration of the physical properties of the film.

The hydrophilic coating agent of the present invention can form a hydrophilic film on an object to be coated, and can particularly be applied to aluminum and aluminum alloy plates and chemically treated surfaces thereof.

Moreover, when a higher degree of corrosion resistance is required, a corrosion-resistant organic resin can be coated between the hydrophilic coating agent of the present invention and the surface to be coated.

As a coating method for the hydrophilic coating material of the present invention, various known methods such as brushing, dipping, spraying, electrostatic coating, and roll coater can be applied. A coloring agent or the like may be added to the coating film for aesthetic purposes or other purposes.

The drying and curing conditions of the coated hydrophilic coating should be taken into consideration in accordance with the speed of the production line, but it can usually be carried out under the conditions of a heating temperature of 120 to 280°C and a heating time of 5 seconds to 20 minutes. By curing, it is possible to form a cured resin coating layer that is not only highly hydrophilic but also has excellent coating film properties.

Further, processing of the fin material into a heat exchanger can be performed by a known method, and coating of the coating material of the present invention on the heat exchanger fins may be performed by either a pre-coating method or a post-coating method.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 ■ Synthesis of hydrophilic resin 1 equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe
51 In a separable flask, add 2-acrylamido-2-methylpropanesulfonic acid (30 parts) and methacrylic acid (
20 parts), 2-hydroxyethyl acrylic I/-) (30 parts
100 parts of isopropanol and 400 parts of demineralized water were added and uniformly dissolved. A solution prepared by dissolving 710 parts of caustic saw in 100 parts of demineralized water was added to this solution for neutralization.

Under a nitrogen gas atmosphere, 0.4 parts of potassium persulfate and 0.2 parts of sodium sulfite were added, and polymerization was carried out at 30° C. for 6 hours in a redox system. Thereafter, the concentration was adjusted to 10% with demineralized water.

■ Preparation of hydrophilic coating agent Hydrophilic resin synthesized in above ■ 50 parts trimethylol melamine 2 parts pH with aqueous ammonia ■
7, and the solid content was adjusted to 5% with ion-exchanged water.

■ The coating thickness on aluminum is 0.12 (le+e) industrial pure aluminum (A
1050-H22) was degreased and washed using a commercially available weak alkaline degreaser. Next, a phosphoric acid chromate-based chemical solution (trade name: Allozin 401/45, manufactured by Nippon Paint ■)
After spray treatment, a phosphoric acid chromate film (Crj
After forming 2[]B/+') as 1, it was washed with water and dried. Next, the hydrophilic coating material shown in the above example was applied onto this chemical conversion film using a roll coater, and baked in a hot air circulation drying oven at a temperature of 230°C for 30 seconds to form a hydrophilic resin film layer (
A thickness of 1 μff1) was obtained.

Example 2 A hydrophilic coating material was prepared using the hydrophilic resin synthesized in Example 1 according to the following formulation.

Hydrophilic resin synthesized in Example 1■ 50 parts dimethoxymethyl urea 2.8 parts diammonium phosphate
The pH was adjusted to 7 with 0.1 part ammonia water, and the solid content was brought to 5% with ion-exchanged water.

The coating material thus obtained was applied onto phosphoric acid chromate treated aluminum in the same manner as in Example 1, and
It was heated and dried for 0 seconds.

Example 3 ■ Synthesis of hydrophilic resin 2-acrylamido-2-methylpropanesulfonic acid 1
0 parts, 20 parts of styrene sulfonic acid, 10 parts of 2-hydroxypropyl acrylate, polyethylene glycol (n
-4) 25 parts of monomethacrylate, 25M of methacrylic acid
, 10 parts of N-methoxymethylacrylamide, 4 parts of demineralized water
00 parts and 100 parts of Improper Tool were added and uniformly dissolved.

Neutralized with 8 parts of caustic soda, then adjusted to pH-7 with 25% aqueous ammonia, and then dissolved in benzoyl peroxide, 5 parts.
After dispersion and dissolution, the mixture was mixed at 60 to 70°C for 6 hours.

Thereafter, the concentration was adjusted to 10 parts with demineralized water.

(2) Preparation of hydrophilic coating agent 50 parts of the hydrophilic resin synthesized in (1) above, 1.4 parts of dimethylol urea, and 1.0 parts of trimethylol melamine were adjusted to a solid content of 5% with ion-exchanged water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

Example 4 ■ Preparation of hydrophilic coating agent 50 parts of hydrophilic resin synthesized in Example 3 ■ 1.0 parts of dimethoxymethylethylene urea Polyethylene glycol diglycidyl ether (n -22> (epoxy equivalent: 587) 1
．． 5 parts of polyglycerol polyglycidyl ether (n=3) (epoxy equivalent: 183) and 0.7 parts were brought to a solid content of 5% and 1° with deionized water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

Example 5 ■ Preparation of hydrophilic coating agent 50 parts of hydrophilic resin synthesized in Example 1 ■ Hydantoin diglycidyl (epoxy equivalent L15) 'l, 91
The solids content was brought to 5% with partially exchanged water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

Example 6 ■ Preparation of hydrophilic coating agent 50 parts of hydrophilic resin synthesized in Example 1 ■ Amount of polyethylene glycol diglycidyl ether (Rho 22) (Epoxy equivalent 587) 5.0
1 part glycerol polyglycidyl ether (epoxy equivalent: 141) 1.2 parts ion-exchanged water to bring the solids content to 5%.

(2) Application to aluminum plate The coating material obtained in (1) above is applied to an aluminum surface in the same manner as in Example 1.

The film properties (hydrophilicity, adhesion, continuous formability) were investigated for the fin materials on which the hydrophilic films obtained in Examples 1 to 6 were formed. The results are shown in Table 1.

For hydrophilicity, one cycle is a combination of immersion in water at room temperature for 2 minutes and then drying with cold air for 6 minutes.
After the cycle, the contact angle with water was measured and evaluated as follows. That is, ◎ is very good (contact angle 206 or less), o is good (contact angle 20 to 40''), and × is poor (contact angle over 40''). As a result, it was found that Examples 1 to 6 all exhibited very good hydrophilicity, with contact angles of 40'' or less.

Adhesion was evaluated by a cross-cut tape peeling test, and the number of stitches that did not peel off was determined. None of them peeled off.

Continuous moldability was determined by visually observing the wear of the molding tools and the appearance of the fins after molding after 100,000 consecutive bunch fin presses, and they were all good with no mold wear.

Comparative Examples 1 to 2 After forming a chemical conversion film in the same manner as in Examples, in Comparative Example 1, a water-soluble coating agent consisting of colloidal silica, water-soluble acrylic/melamine resin, and surfactant was applied onto the chemical conversion film. It was dried at ℃ x 30 seconds to obtain a hydrophilic film with a thickness of 1 μm.

In Comparative Example 2, a water-soluble coating agent consisting of sodium-based water glass, polyacrylic acid, and a curing agent was applied and dried to obtain a hydrophilic film with a thickness of 70 B/i' as 5iffi.

Comparative Example 3 (1) Synthesis of hydrophilic resin 40 parts of methacrylic acid, 30 parts of 2-hydroxyethyl acrylate, and 30 parts of acrylamide were charged, 200 parts of ethanol was added, and 300 parts of demineralized water were added and uniformly dissolved. Add 0.4 parts of potassium persulfate and 0.02 parts of sodium sulfite under a nitrogen gas atmosphere, and heat at 30°C using a redox system.
Time polymerization was performed. Thereafter, the concentration was adjusted to 10% with demineralized water.

■ Preparation of hydrophilic coating agent Hydrophilic resin synthesized in step (■) above 50 parts Trimethylolmelamine 3.0 parts pH adjusted with aqueous ammonia
-7, and the solid content was brought to 5% with ion-exchanged water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

Comparative Example 4 ■ Synthesis of hydrophilic resin 2-acrylamide-2-methylpropanesulfonic acid 4
0 parts, 30 parts of 2-hydroxyethyl acrylate, and 30 parts of acrylamide were added, and 100 parts of Impropatool and 400 parts of demineralized water were added to uniformly dissolve. A solution prepared by dissolving 13 parts of caustic soda in 100 parts of demineralized water was added to this solution for neutralization. Under a nitrogen gas atmosphere, 0.4 parts of potassium persulfate and 0.2 parts of sodium sulfite were added, and polymerization was carried out at 30° C. for 6 hours in a redox system. Thereafter, the concentration was adjusted to 10% with demineralized water.

■ Preparation of hydrophilic coating agent Hydrophilic resin synthesized in above (■) 50 parts trimethylolmelamine 1.1 parts pH with aqueous ammonia
-7, and the solid content concentration was made 5% with ion-exchanged water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

Comparative Example 5 ■ Synthesis of hydrophilic resin 2-acrylamido-2-methylpropanesulfonic acid 5
0 parts and 50 parts of methacrylic acid were added, and 100 parts of isopropanol and 400 parts of demineralized water were added to uniformly dissolve.

A solution prepared by dissolving 16.5 parts of caustic soda in 100 parts of demineralized water was added to this solution for neutralization. Under nitrogen gas atmosphere,
0.4 parts of potassium persulfate and 0.2 parts of sodium sulfite were added, and polymerization was carried out at 30° C. for 6 hours in a redox system. Thereafter, the concentration was adjusted to 10 parts with demineralized water.

■ Preparation of hydrophilic coating agent Hydrophilic resin synthesized in step (■) above 50 parts Trimethylolmelamine 2.4 parts pH adjusted with aqueous ammonia
-7, and the solid content was brought to 5% with ion-exchanged water.

(2) Application to aluminum plate The coating material obtained in (1) above was applied to an aluminum surface in the same manner as in Example 1.

The properties of the films obtained in Comparative Examples 1 to 5 were investigated in the same manner as in the Examples, and the results are shown in Table 1.

Although the adhesion was good in both Comparative Examples U and 2.3, mold wear was observed in Comparative Example 1, and in Comparative Example 1, the contact angle exceeded 51°, and in Comparative Example 3, the contact angle exceeded 45". In Comparative Example 4.5, the hydrophilicity was good, but peeling and cracking occurred in the processed part film after continuous molding.

In the heat exchanger manufactured using Table 1, there is no formation of crescent-shaped water droplets, bridges, etc. that obstruct ventilation between the fins, and the heat exchange efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a state in which water droplets adhere between the fins of a conventional heat exchanger. C. Effects of the invention] As explained above, the hydrophilic coating material according to the structure of the present invention has excellent wettability with water, good adhesion to the substrate, and further reduces mold wear during molding. It is possible to form a cured film without any hardening. In addition, the hydrophilicity of the aluminum plate material for fins coated with the coating material is significantly improved, and this patent is patented by Sumitomo Light Metal Industries, Ltd., patent applicant, Kyoeisha Aburashi Chemical Industry Co., Ltd., agent, and patent attorney, Takeshi Komatsu, agent. People Patent Attorney Hiroshi Asahi

Claims (4)

[Claims] (1) A α, β unsaturated monomer having a sulfonic acid group, B
Polymerize with an α,β unsaturated monomer having a hydroxy group, an α,β unsaturated monomer having a C carboxyl group, an α,β unsaturated monomer having a D amide group and/or a methylolamide group A hydrophilic coating material obtained by. (2) A α,β unsaturated monomer having a sulfonic acid group, B
Polymerize with an α,β unsaturated monomer having a hydroxy group, an α,β unsaturated monomer having a C carboxyl group, an α,β unsaturated monomer having a D amide group and/or a methylolamide group A thermosetting hydrophilic coating material comprising a hydrophilic coating material obtained by the method and at least one curing agent selected from the group consisting of a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent. Coating agent. (3) A α, β unsaturated monomer having a sulfonic acid group, B
Polymerize with an α,β unsaturated monomer having a hydroxy group, an α,β unsaturated monomer having a C carboxyl group, an α,β unsaturated monomer having a D amide group and/or a methylolamide group Aluminum or An aluminum or aluminum alloy plate material for fins, which is coated on an aluminum alloy plate material and heat-cured. (4) A α, β unsaturated monomer having a sulfonic acid group, B
Polymerize with an α,β unsaturated monomer having a hydroxy group, an α,β unsaturated monomer having a C carboxyl group, an α,β unsaturated monomer having a D amide group and/or a methylolamide group A hydrophilic thermosetting film formed from the hydrophilic coating material obtained by this method and at least one curing agent selected from the group consisting of a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent is coated on aluminum or A heat exchanger characterized by comprising aluminum alloy fins on the surface thereof.