JPH02219875A - 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 contg. N (e.g. N,N- diethylamino methacrylate) are polymerized together.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to 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 or metal material). The present invention relates to a composition applied to a surface, an aluminum alloy plate material heat-cured with the composition, and a heat exchanger coated with the composition.

[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 be more compact and have improved thermal efficiency in order to reduce weight, and designs have been adopted to make the fin spacing as narrow as possible. Heat exchangers for air conditioners are During cooling operation, moisture in the air becomes condensed water and adheres to the surface of the aluminum fin.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 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 flows down onto the 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. 164264/1982), 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. 60-101
No. 158) 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, a large amount of alkali silicate (containing nails) must be applied to the material and when it is processed into fins, it acts like an abrasive and causes the mold to dry. increases 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 characteristics.

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.
The first invention is a hydrophilic coating material obtained by superimposing an unsaturated monomer, a C carboxyl group-containing α, β unsaturated monomer, and a D nitrogen-containing α, β unsaturated monomer. , A an α,β unsaturated monomer having a sulfonic acid, B an α,β unsaturated monomer having a hydroxy group, C an α,β unsaturated monomer having a carboxyl group, D a nitrogen-containing α, It consists of a hydrophilic coating material obtained by superposing a β-unsaturated monomer 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. The second invention is a thermosetting hydrophilic coating material, in which A is an α- and β-unsaturated monomer having a sulfonic acid group, B is an α- and β-unsaturated monomer having a hydroxyl group, and C is an α-unsaturated monomer having a carboxyl group.

A hydrophilic coating obtained by superimposing a β-unsaturated monomer, a D-nitrogen-containing α, β monomer, and a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent. A third invention is an aluminum or aluminum alloy plate material for fins, which is prepared by coating an aluminum or aluminum alloy plate material with a thermosetting hydrophilic coating material consisting of at least 1t4 of a curing agent and thermosetting the coating material, wherein the aluminum or aluminum alloy plate material has an A sulfonic acid group. , a β unsaturated monomer, B an α, β unsaturated monomer having a hydroxy group, C an α, β unsaturated monomer having a carboxyl group, and D a nitrogen-containing α9 β unsaturated monomer. at least one selected from the group consisting of a methylol curing agent, an etherified methylol curing agent, and a polyepoxide curing agent.
A fourth aspect of the present invention is a heat exchanger comprising a hydrophilic thermosetting film formed on the surface of an aluminum or aluminum alloy fin.

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 anionic sclera water properties and functions to make the polymer water-soluble. Improves wettability. Examples of the human component include 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, and styrenesulfonic acid, with 2-acrylamido-2-methylpropanesulfonic acid being particularly 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. As this component B, for example, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate represented by the following structural formula, polypropylene glycol mono(meth)acrylate CI! 2 = 6-COO(C112C!120), I
I n-2 to 10R-11, cl13 R-11, Ct13, etc., but especially 2-hydroxy, ethyl (meth)acrylate, 2-hydroxypropyl (
Meth)acrylates are preferred.

α, β unsaturated tli with carboxyl group of C component
The fi component 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 nitrogen-containing α,β unsaturated monomer of component D is useful for imparting softness and flexibility to the formed film, as well as adhesion to the aluminum plate. Such components include, for example, N,N-dimethylaminoethyl (meth)acrylate,
N,N-diethylaminoethyl (meth)acrylate,
Examples include vinylpyrrolidone and vinylimidacillin, among which N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and vinylpyrrolidone are particularly preferred.

The polymerization of these A, B, and CSD components is performed by radical polymerization in an aqueous medium. The composition ratio of the co-merged is A/B/
C/D is heavy;% 20~70/lO~8015~B51
A range of 5 to 40 is preferred.

As the intermediate 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 alone or sodium metabisulfite or sodium thiosulfate are preferred. The polymerization may be carried out using a sodium redox system in combination with the polymerization system, or by dissolving an oil-soluble initiator such as azobisisobutyronitrile in a small amount of alcohol and finely dispersing it in the polymerization system. The radical polymerization initiator is preferably used in an amount of 0.1 to 5% by weight based on the monomer.

The polymerization temperature is preferably 20 to 40°C in the case of a redox system, 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. Examples of such organic solvents include lower alcohols such as methanol, ethanol, and isopropanol, and monoalkyl ethers of glycols such as ethylene glycol monoethyl ether and diethylene glycol monoethyl ether. In addition, acetone, dioxane, etc. can also be used. .

The hydrophilic resin obtained in this way contains a sulfonic acid group and a carboxyl group in its aggregated 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 may be carried out after polymerization (or it may 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 one 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 curing agent used varies depending on the functional groups in the resin and the amount of functional groups in the curing agent, but it is used in the range of 0.1 to 60% by weight based on the hydrophilic resin (1.0% 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 is greatly influenced by the temperature and time during thermal curing, as well as the type of curing agent, and it may be difficult to use a highly basic curing agent such as methylolmelamine or 200% curing catalyst.
When curing conditions at a high temperature of .degree. C. or higher are employed, a curing catalyst is generally not necessary, and rather causes deterioration of the physical properties of the film if used.

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 chemical conversion 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 well-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
In a separable flask, add 2-acrylamido-2-methylpropanesulfonic acid (20 parts) and methacrylic acid (
30 parts), 2-hydroxyethyl acrylate (35 parts)
), N,N-diethylamino methacrylate (15 parts), 100 parts of isopropanol, and 400 parts of demineralized water.
of the mixture was added and dissolved uniformly. Add 6.7 ml of caustic soda to this solution.
Neutralization was carried out by adding a solution prepared by dissolving 1 part in 100 parts of demineralized water. Under nitrogen gas atmosphere, azobisisobutyronitrile 0
．． 5 parts were added and the polymerization was continued at 70°C for 6 hours. After m convexity, the solution was neutralized (pH-7) with 25% aqueous ammonia, and then adjusted to a concentration of 10% with demineralized water.

(2) Preparation of hydrophilic coating material Hydrophilic resin synthesized in the above (1) 50 parts trimethylolmelamine 2 parts ion-exchanged water to bring the solids content to 5%.

■ Industrial pure aluminum with a coating thickness of 0.1205 m on aluminum (A 1
050-H22) The strip was degreased and washed using a commercially available weak alkaline degreaser. Next, it was sprayed with a phosphoric acid chromate-based chemical solution (trade name: Allozin 401/45 manufactured by Nippon Paint Co., Ltd.) to form phosphoric acid chromate skin M (Crff
2011 g/lm2) was formed, and then washed with water and dried. Next, the hydrophilic coating 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 250°C for 30 seconds to obtain a hydrophilic resin film layer (thickness: 1 μIm). Ta.

Example 2 ■ Synthesis of hydrophilic resin 2-acrylamido-2-methylpropanesulfonic acid 1
0 parts of vinyl sulfonic acid, 10 parts of vinyl sulfonic acid, 20 parts of 2-hydroxyethyl methacrylate, 25 parts of methacrylic acid, 35 parts of N-vinylpyrrolidone, 300 parts of demineralized water, and 200 parts of isopropanol were added and uniformly dissolved.

After neutralizing with 8.1 parts of caustic soda and adjusting the pH to -7 with 25% aqueous ammonia, 0.0 parts of azoisobutyronitrile was added.
After dispersing and dissolving 3 parts, polymerization was carried out at 130 to 70°C for 6 hours. Thereafter, the concentration was adjusted to 10% with demineralized water.

(2) Preparation of hydrophilic coating 50 parts of the hydrophilic resin synthesized in (1) above and 1.5 parts of hexamethoxymethylmelamine were diluted with ion-exchanged water to a solid content of 5% and 1°.

(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 3 ■ Preparation of hydrophilic coating agent 50 parts of hydrophilic resin synthesized in Example 3 ■ 1.0 part of dimethoxymethyl urea Polyethylene glycol diglycidyl ether (n=9) (epoxy equivalent 286) 0.5 part of glycerol 0.5 part of triglycidyl ether (epoxy equivalent: 141) was 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 Hydrophilic resin synthesized in Example 1 ■ 50 parts Dimethoxymethyl urea 3.0 parts Dibasic ammonium phosphate 0.1 part Ion-exchanged water to bring the solids content to 5% .

(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 (1) Preparation of hydrophilic coating agent 50 parts of the hydrophilic resin synthesized in Example 1 (2) Hydantoin diglycidyl (epoxy equivalent: 135) L5 parts The solid content was adjusted to 5% with ion-exchanged water.

(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.

Example 6 ■ Preparation of hydrophilic coating agent Hydrophilic resin synthesized in Example 2 ■ 50 parts Polyethylene glycol diglycidyl ether (n=13) (epoxy equivalent weight 135) 5.0 parts Hydantoin diglycidyl (epoxy equivalent weight 135) The solids content was brought to 5% with 0.9 parts 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 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. ◎ is very good (contact angle 20″ or less), o is good (contact angle 20 to 40″), and × is bad (contact angle over 40＠).

As a result, it was found that all of them exhibited very good hydrophilicity, with contact angles of 1" or less.

Adhesion was determined by a cross-cut tape peeling test and evaluated by the number of stitches that were not peeled off. All 100/loo
There was nothing to JIIM.

Continuous moldability was determined by visually observing the wear condition of the molding tool and the appearance of the fin after molding after 100,000 batch fins were continuously applied. There was no mold wear in either case (it was completely good).

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 830 degrees Celsius 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 hardening agent was applied and dried to obtain a hydrophilic film with a thickness of 701 g/m' as 5iffi.

Comparative Example 3 ■ Synthesis of hydrophilic resin 35 parts of methacrylic acid, 40 parts of 2-hydroxyethyl acrylate, 25 parts of N,N-diethylamino methacrylate, 200 parts of isopropanol, and 3 parts of demineralized water were charged.
00 parts were added and uniformly dissolved. Under nitrogen gas atmosphere 1. Add 0.5 part of azobisisobutylotryl and heat to 70℃ for 6 hours.
The meeting continued for m hours. After polymerization, neutralize with 25% ammonia water (p)! -7) I, and then adjusted to a concentration of 10 parts with demineralized water.

(2) Preparation of hydrophilic coating agent Hydrophilic resin synthesized in the above (1) 50 parts trimethylolmelamine 1 part ion-exchanged water to bring the solid content to 5%.

(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 to methylpropanesulfonic acid 4
0 parts, 20 parts of N,N-diethylamino methacrylate were charged, and 100 parts of isopropanol and 400 parts of demineralized water were added and uniformly dissolved. To this solution was added 13 parts of caustic soda to 100 ml of demineralized water.

Neutralization was performed by adding a solution dissolved in the solution. Under a nitrogen gas atmosphere, add 0.5 part of azobisisobutyronitrile,
Polymerization was continued for 6 hours at 0°C. After polymerization, the mixture was neutralized (all-7) with 25% aqueous ammonia, and then adjusted to a concentration of 10% with demineralized water.

(2) Preparation of hydrophilic coating agent Hydrophilic resin synthesized in the above (1) 50 parts Trimethylolmelamine 1.4 parts The solid content was adjusted 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 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.

After neutralization with 16.7 parts of caustic soda, 0.5 part of azobisisobutyronitrile was added and polymerization was continued at 70°C for 6 hours.

After polymerization, it was neutralized (pll-7) with 25% aqueous ammonia, and then adjusted to 10%'a degree with demineralized water.

(2) Preparation of hydrophilic coating material Hydrophilic resin synthesized in the above (1) 50 parts trimethylolmelamine 2.4 parts The solid content was adjusted 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. Comparative Examples 1, 2, and 3 all had good adhesion, but mold wear was observed in Comparative Example 1, and in Comparative Example 1, the contact angle exceeded 51''.
Comparative PI 3 also exceeded 45'' and had insufficient hydrophilicity.

Comparative Examples 4.5 had good hydrophilicity, but peeling and cracking occurred in the film after continuous molding.

[Effects of the Invention] As explained above, the hydrophilic coating material according to 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 aluminum plate material for fins coated with this coating material (5) has been significantly improved, and heat exchangers manufactured using this material have the formation of half-moon-shaped water droplets, bridges, etc. that obstruct ventilation between the fins. 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. Patent Applicant Sumitomo Light Metal Industries Co., Ltd. Agent Patent Attorney Hide Komatsu Agent Patent Attorney Hiroshi Asahi

Claims (4)

[Claims] (1) A α, β unsaturated monomer having a sulfonic acid group, B
It is characterized by being obtained by polymerizing an α, β unsaturated monomer having a hydroxy group, an α, β unsaturated monomer having a C carboxyl group, and a D nitrogen-containing α, β unsaturated monomer. Hydrophilic coating material. (2) A α, β unsaturated monomer having a sulfonic acid group, B
Hydrophilic coating obtained by polymerizing an α, β unsaturated monomer having a hydroxy group, an α, β unsaturated monomer having a C carboxyl group, and a D nitrogen-containing α, β unsaturated monomer 1. A thermosetting hydrophilic coating material comprising a curing agent 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. (3) A α, β unsaturated monomer having a sulfonic acid group, B
Hydrophilic coating obtained by polymerizing an α, β unsaturated monomer having a hydroxy group, an α, β unsaturated monomer having a C carboxyl group, and a D nitrogen-containing α, β unsaturated monomer A thermosetting hydrophilic coating agent consisting of a curing agent 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 applied to an aluminum or aluminum alloy plate material and thermoset. An aluminum or aluminum alloy plate material for fins, which is characterized by being stiffened. (4) A α, β unsaturated monomer having a sulfonic acid group, B
Hydrophilic coating obtained by polymerizing an α, β unsaturated monomer having a hydroxy group, an α, β unsaturated monomer having a C carboxyl group, and a D nitrogen-containing α, β unsaturated monomer 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, on the surface of the aluminum or aluminum alloy fin. A heat exchanger characterized by: