JP7193443B2 - Aluminum fin stock - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aluminum fin material, and more particularly to an aluminum fin material suitable for use in heat exchangers such as air conditioners.

Heat exchangers are used in products in various fields such as room air conditioners, package air conditioners, freezer showcases, refrigerators, oil coolers, and radiators. Aluminum and aluminum alloys, which are excellent in thermal conductivity, workability, corrosion resistance, etc., are generally used as materials for fins of heat exchangers. A plate-fin type or plate-and-tube type heat exchanger has a structure in which fins are arranged side by side at narrow intervals.

Condensed water adheres to the fins of the heat exchanger when the surface temperature drops below the dew point. When the hydrophilicity of the surface of the fins is low, the contact angle of the condensed water that adheres to the fins becomes large, causing splashing in the living environment called water splashing. Moreover, when the condensed water is combined and becomes large, it forms a bridge between the adjacent fins, blocks the ventilation passage between the fins, and increases the ventilation resistance.

For the purpose of preventing such splashing of water and reducing airflow resistance, a technique of coating and forming a hydrophilic film on the surface of the fin has been proposed. As an example of such a hydrophilic film, for example, in Patent Document 1, a component consisting of a sodium salt and / or potassium salt of carboxymethyl cellulose, an ammonium salt of carboxymethyl cellulose, and N-methylolacrylamide having a specific composition , a hydrophilic surface treatment agent characterized by containing specific amounts of polyacrylic acid and a zirconium compound.

Japanese Patent No. 2520308

However, when the heat exchanger is operated for a long period of time, not a little of the components constituting the hydrophilic film are eluted into the water due to the contact of water with the surface of the hydrophilic film. Therefore, it is difficult to maintain the hydrophilicity of the fin surface for a long time. One of the reasons for this is adhesion of volatile organic compounds (VOC) floating in the air to the hydrophilic film surface.
When the hydrophilicity of the hydrophilic film decreases, the water bridging between the fins may increase airflow resistance, and the condensed water adhering to the surface of the fins may splash.

The present invention has been made in view of the above circumstances, and an aluminum fin provided with a hydrophilic coating that maintains its hydrophilicity for a long period of time and suppresses the decrease in hydrophilicity due to the adhesion of volatile organic compounds to the fin surface. The purpose is to provide fin material.

The present invention relates to the following [1] to [5].
[1] An aluminum plate and a hydrophilic film layer formed on the aluminum plate are provided in this order, and the hydrophilic film layer comprises a polymer or copolymer resin A and a Zr-based cross-linking agent. , wherein the polymer or copolymer of the resin A contains at least one group selected from the group consisting of a sulfonic acid group, an alkali metal base of sulfonic acid, and an ammonium base of sulfonic acid. Aluminum fin material composed of a monomer having
[2] The resin composition further comprises a resin B that is a polymer or copolymer, and the polymer or copolymer of the resin B is composed of at least a monomer having a carboxyl group. The aluminum fin material according to [1].
[3] The aluminum fin material according to [2], wherein the content ratio of the resin A:the resin B in the resin composition is 20:80 to 80:20 in mass ratio.
[4] The aluminum fin material according to any one of [1] to [3] above, wherein the content of the Zr-based cross-linking agent in the hydrophilic film layer is 0.05 to 6.0% by mass.
[5] The above [1] to [4], further comprising a corrosion-resistant coating layer between the aluminum plate and the hydrophilic coating layer, wherein the hydrophilic coating layer is formed on the surface of the corrosion-resistant coating layer. The aluminum fin material according to any one of the above.
[6] The aluminum fin material according to any one of [1] to [5], which is used for a heat exchanger.

According to the present invention, the decrease in hydrophilicity due to the adhesion of volatile organic compounds to the surface of the hydrophilic coating layer is suppressed while maintaining the hydrophilicity (durability) in which the hydrophilicity is maintained for a long period of time. As a result, the low airflow resistance of the aluminum fin material and the effect of suppressing water splashing can be maintained for a long period of time. Therefore, when such an aluminum fin material is used in a heat exchanger or the like, it is expected that the heat exchanger itself will have a longer life.

FIG. 1 is a schematic cross-sectional view showing one aspect of the configuration of the aluminum fin material. FIG. 2 is a schematic cross-sectional view showing one aspect of the configuration of the aluminum fin material.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the fin material made from aluminum which concerns on this invention is demonstrated in detail. In addition, "-" indicating a numerical range is used to include the numerical values described before and after it as a lower limit and an upper limit.

<Aluminum fin material>
As shown in FIG. 1, the aluminum fin material 10 according to this embodiment comprises an aluminum plate 1 and a hydrophilic film layer 4 on the aluminum plate 1 in this order. Moreover, it is preferable that a corrosion-resistant coating layer 3 is provided between the aluminum plate 1 and the hydrophilic coating layer 4 , and the hydrophilic coating layer 4 is formed on the surface of the corrosion-resistant coating layer 3 .
The hydrophilic film layer 4 is made of a resin composition containing resin A, which is a polymer or copolymer, and a Zr-based cross-linking agent. Here, the polymer or copolymer of the resin A is a monomer having at least one group selected from the group consisting of a sulfonic acid group, an alkali metal base of sulfonic acid, and an ammonium base of sulfonic acid. Configured.
Further, the aluminum fin material may be provided with a surface treatment layer 2 between the aluminum plate and the corrosion-resistant coating layer, if necessary. Moreover, the surface of the hydrophilic film layer 4 may be further provided with a lubricating film layer 5 .

(Hydrophilic coating layer)
The resin composition forming the hydrophilic film layer 4 contains a resin A and a Zr-based cross-linking agent. The hydrophilic film layer preferably further contains a resin B because the hydrophilicity of the hydrophilic film layer can be better maintained over a long period of time.
Here, the resin A contains at least one group selected from the group consisting of a sulfonic acid group, an alkali metal base of sulfonic acid, and an ammonium base of sulfonic acid (hereinafter simply referred to as "sulfonic acid group, etc."). It is a polymer or copolymer composed of monomers having Resin B is a polymer or copolymer composed of at least a monomer having a carboxyl group.

By including the resin A in the resin composition, a hydrophilic function can be imparted to the resin composition.
Resin A may be a polymer (homopolymer) consisting of only one type of monomer, or a copolymer consisting of two or more types of monomers. When it is a copolymer, it may be an alternating copolymer, a block copolymer, a graft copolymer, a random copolymer, or the like, and the method of arranging the monomers is not particularly limited.

When the resin A is a polymer, it is a polymer composed of one monomer having at least one group selected from the group consisting of sulfonic acid groups, alkali metal bases of sulfonic acid, and ammonium bases of sulfonic acid. is. Further, when the resin A is a copolymer, one or more of the monomers constituting the copolymer consist of a sulfonic acid group, an alkali metal base of sulfonic acid, and an ammonium base of sulfonic acid. A monomer having at least one group selected from the group may be used.

The resin composition may contain, as the resin A, only one kind selected from the group consisting of these polymers and copolymers, or two or more kinds thereof. When two or more types are included, the content of resin A in the hydrophilic film layer or resin composition means the total content of those polymers and copolymers.

Specific examples of resin A include a polymer consisting only of a monomer having a sulfonic acid group, a polymer consisting only of a monomer having an alkali metal base of sulfonic acid, and a monomer having an ammonium base of sulfonic acid. a polymer containing a monomer having a sulfonic acid group, a copolymer containing a monomer having a sulfonic acid alkali metal base, a copolymer containing a monomer having a sulfonic acid ammonium base polymers.

The main chain structure of the monomer constituting the resin A is not particularly limited as long as it has a sulfonic acid group, an alkali metal base of sulfonic acid, or an ammonium base of sulfonic acid. Alkali metal bases of sulfonic acids include, for example, groups forming lithium salts, sodium salts, potassium salts, and the like.

The monomer constituting the resin A preferably has an ethylenically unsaturated bond in the structure of the portion constituting the main chain. Specific examples of such monomers include acrylic acid derivatives, methacrylic acid derivatives, acrylamide derivatives, methacrylamide derivatives, vinyl derivatives, styrene derivatives, etc. having a sulfonic acid group.

More specifically, resin A is preferably polyvinylsulfonic acid, polyvinylsulfonate, or acrylic acid-vinylsulfonic acid copolymer. Such a resin has high hydrophilicity, and when the resin composition contains the resin B, the compatibility with the resin B is also good.
Specific examples of resin A include "Aqualic (registered trademark) GL" manufactured by Nippon Shokubai, "ATBS (registered trademark)" manufactured by Toagosei, and "VSA-H (trade name)" manufactured by Asahi Kasei Finechem. can be done.

In addition to the resin A, the resin composition contains at least a resin B, which is a polymer or copolymer composed of a monomer having a carboxyl group, so that the hydrophilicity of the hydrophilic film layer can be maintained for a long time. It is preferable because it can be expressed over a period of time and is excellent in durability.
Resin B may be a polymer (homopolymer) consisting of only one type of monomer, or a copolymer consisting of two or more types of monomers. When it is a copolymer, it may be an alternating copolymer, a block copolymer, a graft copolymer, a random copolymer, or the like, and the method of arranging the monomers is not particularly limited.

When the resin B is a polymer, it is a polymer composed of one type of monomer having a carboxyl group. Moreover, when the resin B is a copolymer, at least one of the monomers constituting the copolymer may be a monomer having a carboxyl group.

The resin composition may contain, as the resin B, only one selected from the group consisting of these polymers and copolymers, or two or more thereof. When two or more types are included, the content of resin B in the hydrophilic film layer or resin composition means the total content of those polymers and copolymers.

Specific examples of the resin B include a polymer consisting only of a monomer having a carboxyl group, and a copolymer containing a monomer having a carboxyl group.
The main chain structure of the monomer constituting the resin B is not particularly limited as long as it has a carboxyl group.

The monomer constituting the resin B preferably has an ethylenically unsaturated bond in the structure of the portion constituting the main chain. Specific examples of such monomers include acrylic acid, methacrylic acid, and acrylamide derivatives, vinyl derivatives, and styrene derivatives having a carboxyl group.

More specifically, if the resin B is the same as the resin in the corrosion-resistant coating layer, the coating strength of the hydrophilic coating layer and the adhesion between the corrosion-resistant coating layer and the hydrophilic coating layer can be increased. Examples of such resins include acrylic acid-based resins.

The ratio of the resin A and the resin B in the resin composition can be mixed at an appropriate ratio in consideration of paintability, workability, physical properties of the film, and the like. However, from the viewpoint of sufficiently ensuring the hydrophilicity of the hydrophilic film layer, the mass ratio in terms of solid content is preferably resin A: resin B = 20: 80 to 80: 20, and 30: 70 to 80. :20 is more preferable. The proportion of resin A and resin B in the resin composition is the same as the proportion of resin A and resin B in the hydrophilic film layer.

The resin composition further contains a Zr-based cross-linking agent. By including the Zr-based cross-linking agent, the hydrophilicity of the resin A can be maintained for a long period of time, and the durability of the hydrophilicity is improved. Furthermore, it is possible to suppress the decrease in hydrophilicity due to the adhesion of volatile organic compounds to the surface of the hydrophilic film layer, and to realize good stain resistance.

The Zr-based cross-linking agent may be any compound containing Zr and acting as a cross-linking agent. Examples thereof include zirconium nitrate, zirconium acetate, ammonium zirconium carbonate, zirconium hydrofluoric acid, and salts thereof.
By using a Zr-based cross-linking agent, unlike conventional oxazoline-based cross-linking agents, etc., the hydrophilic effect of resin A and the hydrophilic effect of resin B can be maintained for a long period of time. Adhesion of volatile organic compounds can be effectively prevented.

The content of the Zr-based cross-linking agent in the hydrophilic film layer is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of satisfactorily preventing adhesion of volatile organic compounds to the surface of the hydrophilic film layer. is more preferred. On the other hand, the content is preferably 8.0% by mass or less, and 6.0% by mass, in order to prevent the decrease in the hydrophilicity of the hydrophilic film layer due to the decrease in the functional groups of the resin A and the resin B due to an excessive increase in the amount of cross-linking. % by mass or less is more preferable.

In addition to the above, the resin composition further contains various water-based solvents and paint additives for improving paintability, workability, physical properties of the film, etc., as long as the effects of the present embodiment are not impaired. good too. Paint additives include, for example, water-soluble organic solvents, surfactants, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, anti-foaming agents, anti-rust agents, and antibacterial agents. One of these paint additives may be contained, or two or more thereof may be contained.

The thickness of the hydrophilic film layer is preferably 0.1 mg/dm ² or more, more preferably 0.5 mg/dm ² or more, more preferably 1 mg/dm ² from the viewpoint of obtaining good hydrophilicity. The above is more preferable. In addition, the adhesion amount is preferably 15 mg/dm ² or less, and 10 mg/dm ² or less from the viewpoint of obtaining good film formation properties with suppressed defects such as cracks and high heat exchange efficiency with low heat transfer resistance. More preferably, it is 8 mg/dm ² or less.

The coating amount of the hydrophilic coating layer depends on the concentration of the coating composition used for forming the hydrophilic coating layer and the bar coater No. used for forming the coating. can be adjusted by selecting In addition, the coating amount of the hydrophilic coating layer can be measured by fluorescent X-ray, infrared film thickness meter, weight measurement by coating peeling, or the like.

(aluminum plate)
The aluminum plate 1 is a concept including a plate made of aluminum and a plate made of an aluminum alloy, and an aluminum plate conventionally used for aluminum fin materials can be used.
As the aluminum plate, it is preferable to use 1000 series aluminum specified in JIS H 4000:2014 because of its excellent thermal conductivity and workability. More specifically, aluminum with alloy numbers 1050, 1070 and 1200 is preferably used as the aluminum plate. However, the above description does not exclude the use of 2000 series to 9000 series aluminum alloys and other aluminum plates as the aluminum plate.

The thickness of the aluminum plate can be appropriately adjusted depending on the application and specifications of the fin material. Regarding the fin material for heat exchangers, the thickness is preferably 0.08 mm or more, more preferably 0.1 mm or more, from the viewpoint of the strength of the fins. On the other hand, it is preferably 0.3 mm or less, more preferably 0.2 mm or less, from the viewpoint of workability into fins, heat exchange efficiency, and the like.

(Underlayer)
The undercoat layer 2 is a layer that can be provided between the aluminum plate 1 and the corrosion-resistant coating layer 3 as desired. By providing the undercoat layer 2 , the corrosion resistance of the aluminum plate 1 can be enhanced, and the adhesion between the aluminum plate 1 and the corrosion-resistant coating layer 3 can be enhanced.

A conventionally known layer can be used as the base treatment layer, and for example, a layer made of an inorganic oxide or an inorganic-organic composite compound can be used.
As the inorganic oxide, an oxide containing chromium (Cr) or zirconium (Zr) as a main component is preferable. Specific examples of such inorganic oxides include oxides formed by phosphate chromate treatment, zirconium phosphate treatment, chromate chromate treatment, zinc phosphate treatment, phosphate titanate treatment, and the like. However, the types of inorganic oxides are not limited to those formed by these treatments.

Examples of inorganic-organic composite compounds include compounds formed by coating-type chromate treatment, coating-type zirconium treatment, and the like. Specific examples of such inorganic-organic composite compounds include acryl-zirconium composites.

It is preferable that the undercoat layer is formed so that the deposition amount of metal elements such as Cr and Zr in terms of mass is 0.01 to 1 mg/dm ² . Good corrosion resistance can be obtained by setting the adhesion amount within the above range.
The thickness of the undercoat layer may be set appropriately according to the use of the fin material, but is preferably 1 to 100 nm, for example.

The adhesion amount of the undercoat layer can be adjusted by adjusting the concentration of the chemical conversion treatment liquid used for forming the undercoat layer and the film formation processing time. Also, the adhesion amount of the base treatment layer can be measured by fluorescent X-ray, infrared film thickness meter, weight measurement by elution, or the like.

(Corrosion-resistant coating layer)
The corrosion-resistant coating layer 3 is a layer that may be provided mainly for enhancing the corrosion resistance of the aluminum plate 1 . The corrosion-resistant film layer 3 makes it difficult for water such as condensed water, oxygen, ion species such as chloride ions, etc. to enter the aluminum plate 1, causing corrosion of the aluminum plate 1 and generation of aluminum oxides that generate odors. is suppressed.

A conventionally known material can be used for the corrosion-resistant film layer, and examples thereof include a resin composition containing an acrylic acid-based resin. By using an acrylic acid-based resin, a corrosion-resistant film layer can be formed with good coatability using a water-based paint.
The acrylic resin forms hydrogen bonds, and is crosslinked by dehydration condensation when baked during film formation. Therefore, the coating strength of the corrosion-resistant coating layer and the adhesion with other coating layers can be enhanced.

The acrylic resin is specifically composed of a polymer or copolymer obtained by polymerizing at least one of acrylic acid and acrylate. That is, it may be a polymer (homopolymer) consisting of only one type of monomer, or a copolymer consisting of two or more types of monomers. When it is a copolymer, it may be an alternating copolymer, a block copolymer, a graft copolymer, a random copolymer, or the like, and the method of arranging the monomers is not particularly limited.

When the acrylic resin is a polymer, it is a polymer containing acrylic acid or an acrylate as a monomer. Further, when the acrylic resin is a copolymer, one or more monomers constituting the copolymer may be acrylic acid or an acrylate.

The acrylic resin may contain only one selected from the group consisting of these polymers and copolymers, or may contain two or more.

Specific examples of acrylic acid-based resins include polymers consisting only of acrylic acid monomers, polymers consisting only of acrylate monomers, and copolymers having acrylic acid as at least one monomer. Examples thereof include polymers and copolymers having an acrylate as at least one monomer.
In the case of a copolymer, the other monomer may be acrylic acid, acrylate, or other compounds. Other compounds are not particularly limited as long as they are monomers having a reactive group polymerizable with acrylic acids, and examples thereof include ethylene, propylene, styrene, and maleic acid.

The acrylic acid-based resin may be chain-like or cross-linked via a cross-linking agent.
Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, carbodiimide-based cross-linking agents, and aziridine-based cross-linking agents. Further, the acrylic resin may be crosslinked by dehydration condensation that occurs during baking during film formation. Crosslinking by dehydration condensation may be formed via polyols such as carboxymethylcellulose, polyvinyl alcohol, and polyethylene oxide.

More specifically, the acrylic resin is more preferably one or more selected from the group consisting of polyacrylic acid, alkali metal salts of polyacrylic acid, and ammonium polyacrylate. Examples of alkali metal salts of polyacrylic acid include sodium polyacrylate and potassium polyacrylate. By using these resins, high film strength and adhesion can be obtained.

Specific examples of acrylic resins include "Aqualic (registered trademark) HL" manufactured by Nippon Shokubai Co., Ltd., "Neocryl (registered trademark) A-614" manufactured by Kusumoto Kasei, and "Baltop (registered trademark)" manufactured by Nihon Parkerizing. , Toagosei Co., Ltd. “Jurimar (registered trademark)”, Toagosei Co., Ltd. “Aron (registered trademark)”, Taisei Fine Chemical Co., Ltd. “Acryt (registered trademark) AKW”, and the like.

The corrosion-resistant coating layer may contain, in addition to the resins constituting the resin composition, various aqueous solvents and coating additives for improving paintability, workability, physical properties of the coating, and the like. Paint additives include, for example, water-soluble organic solvents, cross-linking agents, surfactants, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, anti-foaming agents, anti-rust agents, antibacterial agents and the like. . One of these paint additives may be added alone, or a plurality of them may be added.

The thickness of the corrosion-resistant coating layer is preferably such that the coating amount of the corrosion-resistant coating layer is 0.3 to 50 mg/dm ² . From the viewpoint of obtaining good corrosion resistance and adhesion between layers, the adhesion amount is preferably 0.3 mg/dm ² or more, more preferably 4 mg/dm ² or more, further preferably 5 mg/dm ² or more, and 10 mg/dm ² or more. The above is even more preferable. On the other hand, from the viewpoint of good film formability, reduced defects such as cracks, low heat transfer resistance of the corrosion-resistant film layer, and good heat exchange efficiency of the fin, the adhesion amount is 50 mg / dm ² or less is preferable, 30 mg/dm ² or less is more preferable, and 20 mg/dm ² or less is even more preferable.

The adhesion amount of the corrosion-resistant coating layer depends on the concentration of the coating composition used for forming the corrosion-resistant coating layer and the bar coater No. used for forming the coating. can be adjusted by selecting Also, the amount of the corrosion-resistant coating layer attached can be measured by fluorescent X-ray, infrared film thickness meter, weight measurement by coating peeling, or the like.

(Lubricating coating layer)
The lubricating coating layer 5 may be provided on the outermost surface of the aluminum fin material 1 mainly to increase the lubricity of the surface of the fin material. That is, it can be provided on the surface of the hydrophilic film layer 4 .
The lubricating coating layer reduces the coefficient of friction on the surface of the fin material, and improves the press formability and the like when processing the fin material into fins.

The lubricating coating layer is not particularly limited as long as it is a conventionally known one. For example, a resin composition containing one or more resins selected from the group consisting of polyethylene glycol, carboxymethyl cellulose and alkali metal salts of carboxymethyl cellulose. Become. Alkali metal salts of carboxymethylcellulose include sodium salts, potassium salts, calcium salts and the like.
These resins may be subjected to known modifications such as urethane modification and alkyl modification by copolymerization with other monomers.
Among them, a mixed resin of polyethylene glycol and sodium carboxymethylcellulose is preferred. More preferably, the weight ratio expressed by polyethylene glycol:sodium carboxymethylcellulose is in the range of 50:50 to 90:10. By setting it as such a composition, the film-forming property and lubricity become much more favorable.

The thickness of the lubricating coating layer is preferably such that the adhesion amount of the lubricating coating layer is 0.1 to 8.0 mg/dm ² . From the viewpoint of obtaining good lubricity, the adhesion amount is preferably 0.1 mg/dm ² or more, more preferably 0.2 mg/dm ² or more. On the other hand, from the viewpoint of obtaining sufficient lubricity and keeping the heat transfer resistance low, the adhesion amount is preferably 8.0 mg / dm ² or less, and from the viewpoint of reducing the adhesion amount as much as possible, 4.0 mg /dm ² or less is more preferable.

The adhesion amount of the lubricating coating layer depends on the concentration of the coating composition used for forming the lubricating coating layer and the bar coater No. used for forming the lubricating coating layer. can be adjusted by selecting Also, the adhesion amount of the lubricating coating layer can be measured by fluorescent X-ray, infrared film thickness meter, weight measurement by coating peeling, or the like.

(Structure of aluminum fin material)
As shown in FIG. 1, the aluminum fin material 10 according to the present embodiment includes the above-described coating layers, that is, the base treatment layer 2 as necessary, the surface treatment layer 2 as necessary, and A corrosion-resistant coating layer 3, a hydrophilic coating layer 4, and, if necessary, a lubricating coating layer 5 are sequentially formed. Each of these coating layers may be formed on the other main surface of the aluminum plate 1 as shown in FIG. The composition of each coating layer on both main surfaces may be the same or different.

The preferred thickness of the aluminum fin material varies depending on the application and the like. For example, when used in a heat exchanger, the thickness is preferably 0.08 mm or more, more preferably 0.1 mm or more, from the standpoint of strength that can withstand processing. From the viewpoint of workability and heat exchange efficiency, the thickness is preferably 0.3 mm or less, more preferably 0.2 mm or less.

The aluminum fin material is preferably used for those having a narrow fin pitch (interval between fin materials). This is because the narrower the fin pitch, the greater the draft resistance due to the water bridging between the fins and the more likely it is for the condensed water adhering to the fin surface to splatter, and the effects of this embodiment are particularly effective. is.

Applications of such a fin pitch include heat exchangers such as air conditioners, heat exchangers for automobiles, and the like. Among them, aluminum fin materials are preferably used for heat exchangers such as air conditioners.

<Method for manufacturing aluminum fin material>
Next, an example of a method for manufacturing the aluminum fin material 10 will be described, but the fin material 10 is not limited to this aspect, and can be manufactured by other manufacturing methods within a range that does not impair the effects of the present embodiment.
The aluminum fin material 10 according to the present embodiment can be manufactured through, for example, a substrate manufacturing process and a coating layer forming process.

(Substrate manufacturing process)
In the substrate manufacturing process, an aluminum plate 1 is manufactured.
For example, the base metal is melted and the molten metal is solidified into an arbitrary shape to obtain an ingot containing a predetermined amount of chemical components such as Al. Then, the ingot is chamfered as necessary, and subjected to hot rolling or cold rolling to obtain an aluminum plate. In producing the aluminum plate, the ingot may be subjected to homogenization heat treatment, or may be subjected to intermediate annealing during rolling. Further, the rolled plate material may be subjected to solution heat treatment, refining, or the like.

(Coating layer forming step)
In the coating layer forming step, a coating layer is formed on the surface of the aluminum plate 1 . Specifically, the hydrophilic film layer 4 is formed on the aluminum plate 1 whose surface is cleaned and degreased as necessary. If desired, the corrosion-resistant coating layer 3 may be formed on the surface of the aluminum plate 1, and then the hydrophilic coating layer 4 may be formed in this order. Between the aluminum plate 1 and the corrosion-resistant film layer 3, it is preferable to further form a surface treatment layer 2 as necessary. In addition, it is preferable to form a lubricating coating layer 5 on the surface of the hydrophilic coating layer 4, that is, on the outermost surface of the aluminum fin material 10, if necessary.

The undercoat layer 2 can be formed by applying a chemical conversion treatment liquid to the aluminum plate 1 by spraying or by immersing the aluminum plate 1 in the chemical conversion treatment solution and then heating and drying the aluminum plate 1 .

The corrosion-resistant coating layer 3 and the lubricating coating layer 5 are formed by dispersing the resin constituting the coating layer in a solvent to obtain a coating composition. It can be formed into a film by baking after coating with a sintering agent. Although the baking temperature for coating is not particularly limited, it is usually carried out in the range of about 100 to 300°C. If the corrosion-resistant coating layer further contains a paint additive, the paint additive may be added to the paint composition and applied, and the paint may be baked at a temperature below which the paint additive does not decompose.

The hydrophilic film layer 4 is formed by dispersing the resin A, the Zr-based cross-linking agent, and optionally the resin B in an arbitrary ratio in an aqueous solvent to obtain a coating composition, followed by a coating device such as a bar coater or a roll coater. is applied to the surface of the corrosion-resistant film layer using and then baked to form a hydrophilic film layer made of the resin composition.

The paint baking temperature of the hydrophilic film layer can be appropriately set according to the type of resin A, the type of resin B, the type of Zr-based cross-linking agent, their mixing ratio, etc., but is usually 150 to 300°C. can be done within the range of From the viewpoint of increasing the film strength and adhesion of the hydrophilic film layer, the paint baking temperature is preferably 190° C. or higher, more preferably 200° C. or higher. On the other hand, from the viewpoint of avoiding thermal decomposition of the resin, the paint baking temperature is preferably 260° C. or less, more preferably 250° C. or less.

Through the above steps, the aluminum fin material according to the present embodiment can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples, and can be modified within the scope of the purpose. It is also possible to implement it, and all of them are included in the technical scope of the present invention.

(Examples 1 to 13 and Comparative Examples 1 to 5)
As the aluminum plate, a standard alloy number 1200 specified in JIS H 4000:2014 with a thickness of 0.1 mm was used. An undercoating layer was formed on one surface of the aluminum plate by phosphoric acid chromate treatment. Next, a coating composition containing a corrosion-resistant film layer resin (acrylic resin, manufactured by Toagosei Co., Ltd.) was applied with a bar coater and baked to form a corrosion-resistant film layer with an adhesion amount of 4 mg/dm ² .
Next, a coating composition obtained by dispersing the composition shown in Table 1 in water was applied to the surface of the corrosion-resistant film layer using a bar coater so that the coating amount of the hydrophilic film layer was the value shown in Table 1. was applied to Subsequently, baking was performed at 200° C. to form a hydrophilic coating layer made of the resin composition.
Finally, a coating composition containing a lubricating coating layer resin (Pascor, manufactured by Meisei Chemical Co., Ltd.) was applied to the surface of the hydrophilic coating layer so that the coating amount was 1.0 mg/dm ² using a bar coater. A lubricating film layer was formed by coating with and baking to obtain an aluminum fin material.
In Table 1, Resin A is a polymer composed of a monomer having a sulfonic acid group, Resin B is a polymer composed of a monomer having a carboxyl group, and a cross-linking agent is a Zr-based cross-linking agent. However, as the cross-linking agent in Comparative Example 5, Epocross (registered trademark) (manufactured by Nippon Shokubai Co., Ltd.), which is an oxazoline-based cross-linking agent, was used.

The obtained aluminum fin material was evaluated for stain resistance and hydrophilicity persistence, which indicates durability, by the following methods.

(stain resistance)
The aluminum fin material was immersed in tap water with a flow rate of 1 L/min for 16 hours. Next, as volatile organic compounds (VOP), paraffin, palmitic acid, stearic acid, dioctyl phthalate (DOP), and stearyl alcohol were placed in a 5 L glass desiccator containing 0.5 g each, and an aluminum fin material was added. was enclosed. Next, a total of 5 cycles of heating the entire glass desiccator at 100° C. for 8 hours were performed, thereby attaching VOP to the surface. After that, the aluminum fin material is returned to room temperature, about 0.5 μL of pure water is dropped on the surface, and the contact angle is measured using a contact angle measuring instrument (manufactured by Kyowa Interface Science Co., Ltd.: CA-05 type). did.
The evaluation criteria were as follows. As a result, the degree of decrease in hydrophilicity (stain resistance) of the surface of the aluminum fin material due to the adhesion of VOP to the surface of the hydrophilic film layer is evaluated. The results are also shown in Table 1.
<Evaluation Criteria>
○ Very good: contact angle is 26 ° or less △ Good (pass): contact angle is over 26 ° and 30 ° or less × Poor (fail): contact angle is over 30 °

(hydrophilic persistence)
A process of exposing the aluminum fin material to deionized water at a flow rate of 0.1 mL/min for 8 hours and then drying it at 80° C. for 16 hours was defined as one cycle, and a total of 14 cycles of this process were performed. After that, the aluminum fin material is returned to room temperature, about 0.5 μL of pure water is dropped on the surface, and the contact angle is measured using a contact angle measuring instrument (manufactured by Kyowa Interface Science Co., Ltd.: CA-05 type). did.
The evaluation criteria were as follows. Thereby, the hydrophilicity durability (hydrophilicity persistence) of the surface of the aluminum fin material is evaluated. The results are also shown in Table 1.
<Evaluation Criteria>
○ Very good: contact angle is less than 40° △ Good (accepted): contact angle is 40° to 60°
× Poor (failed): contact angle exceeds 60 °

From the results of Example 1 and Comparative Example 1, the use of the resin A and the Zr cross-linking agent in the hydrophilic film layer improves the stain resistance. This effect was not seen in the combination of resin B and Zr cross-linking agent (Comparative Example 4), and was also seen in the case of using an oxazoline-based cross-linking agent conventionally used in aluminum fin materials (Comparative Example 5). Therefore, it can be said that the effect is achieved only by combining the resin A and the Zr cross-linking agent.
Further, in addition to the resin A and the Zr-based cross-linking agent, the presence of a predetermined amount of the resin B further improves the stain resistance and the hydrophilicity retention (Examples 1 to 10). Example 5).
The content of the Zr-based cross-linking agent was as small as 0.2% by mass (0.2 parts by mass), but the effect on stain resistance and hydrophilicity persistence was remarkable (Example 4 and Comparative Example 3).
Regarding the thickness of the hydrophilic coating layer, it was confirmed that even if the coating amount was as small as 1 mg/dm ² , sufficient effects were exhibited (Example 10).

Reference Signs List 1 aluminum plate 2 surface treatment layer 3 corrosion-resistant coating layer 4 hydrophilic coating layer 5 lubricating coating layer 10 aluminum fin material

Claims (4)

An aluminum plate and a hydrophilic coating layer formed on the aluminum plate are provided in this order,
The hydrophilic film layer is made of a resin composition containing a polymer or copolymer resin A, a Zr-based cross-linking agent, and a polymer or copolymer resin B ,
The polymer or copolymer of the resin A comprises at least a monomer having at least one group selected from the group consisting of a sulfonic acid group, an alkali metal base of sulfonic acid, and an ammonium base of sulfonic acid ,
The polymer or copolymer of the resin B is composed of at least a monomer having a carboxyl group,
An aluminum fin material, wherein the content of the Zr-based cross-linking agent in the hydrophilic film layer is 0.05 to 6.0% by mass . 2. The aluminum fin material according to claim 1 , wherein the content ratio represented by said resin A: said resin B in said resin composition is 20:80 to 80:20 in mass ratio. 3. The aluminum fin material according to claim 1 , further comprising a corrosion-resistant coating layer between said aluminum plate and said hydrophilic coating layer, wherein said hydrophilic coating layer is formed on the surface of said corrosion-resistant coating layer. . The aluminum fin material according to any one of claims 1 to 3 , which is used in a heat exchanger.

Images