JPH11201688A - Fin material for heat-exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fin material for an heat-exchanger which is excellent in extended hydrophilic durability while low order property characteristics to a resin group treated material is maintained. SOLUTION: On an aluminum plate surface, an anti-corrosion coat comprising a chromate coat or a zirconium-based coat is formed. And over the anti- corrosion coat, a first hydrophilic resin coat comprising a rough with interval of 10 μm or less is formed on surface. Further on the hydrophilic resin coat, a second hydrophilic resin coat wherein a water-soluble resin which comprises, in molecule at least one kind of functional group selected among the group consisting of a hydroxyl group, ester group, amino group, carboxyl group, and ether group is mixed with zirconium compound (0.01-50 parts by weight of zirconium compound for 100 parts by weight of water-soluble resin), comprising a rough with interval of 0.5 μm or less on surface, is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin material for a heat exchanger made of aluminum or an aluminum alloy material having a film formed on a surface thereof, and more particularly, to a fin material for a heat exchanger for home use which has a long-lasting hydrophilicity suitable. It relates to an excellent fin material for a heat exchanger.

[0002]

2. Description of the Related Art Heat exchangers are used in various fields such as room air conditioners, package air conditioners, freezer showcases, refrigerators, oil coolers and radiators. In these heat exchangers, aluminum or aluminum alloy materials having excellent heat conductivity and workability are used as fin materials for heat exchangers such as room air conditioners and package air conditioners. Hereinafter, aluminum and aluminum alloy materials are collectively referred to as aluminum materials.

[0003] The surface of the fin material for a heat exchanger is usually subjected to anticorrosion treatment for preventing the occurrence of corrosion. Further, in order to prevent condensed water from remaining in the fins during cooling operation, a surface treatment for improving water repellency to enhance the dropping property of granular water droplets or a surface treatment for improving the hydrophilicity to enhance the dropping property of water film-like water droplets. Is applied to the fin surface.

When a surface treatment for enhancing hydrophilicity is applied to the surface of an aluminum material, the contact angle of water droplets attached to fins made of the aluminum material can be reduced. FIG.
Is a schematic diagram showing a contact angle of a water droplet on a plane, and FIG. 2 is a schematic diagram showing a heat exchange part of a heat exchanger. As shown in FIG. 1, the contact angle θ refers to the angle between the tangent line 22 of the water droplet at the point A rising from the plane 1 on the surface of the water droplet 2 and the plane 1, and the smaller the contact angle θ, the thinner the water film becomes. ,
Good hydrophilicity. In the heat exchange section of the heat exchanger as shown in FIG. 2, the refrigerant flows in the copper tube 4 passing through the fins 3 in the direction indicated by the arrow.
Although water droplets are condensed on the surface of the film, if the hydrophilicity is good, the water droplets fall well. Therefore, it is possible to prevent the resistance at the time of blowing from being increased by water droplets or a water film adhered to the fins 3, and to obtain excellent heat exchanger characteristics.

FIGS. 3 (a) to 3 (c) are schematic diagrams showing the state of water droplets adhering to the fin surface. In FIG. 3, the length of the downward arrow is proportional to the distance at which a water drop falls in a certain time. As shown in FIG. 3A, when the fin 5 has good hydrophilicity, the contact angle of the water droplet 6 is low, so that the water droplet 6 easily falls along the fin 5. For this reason, since the water droplets 6 do not block the ventilation, the ventilation resistance is reduced. On the other hand, in a heat exchanger composed of fins having poor hydrophilicity, as shown in FIG. 3B, the contact angle of the water droplet 8 is high, so that the water droplet 8 stays on the fin 7, or as shown in FIG. In addition, since the water droplet 11 contacts and stays in both the fin 9 and the fin 10 adjacent to the fin, the water droplet blocks the air flow, and the air flow resistance is significantly increased.

Incidentally, as a surface treatment method for enhancing the hydrophilicity of the fin material, there is the following method. For example, a method of providing a mixed film layer of a water-soluble organic polymer substance and a silicate compound on an aluminum material surface (Japanese Patent Publication No. 3-7744).
No. 0), a method in which a film in which fine silica particles are dispersed in a thermosetting resin is applied to the surface of an aluminum material (Japanese Unexamined Patent Publication No.
No. 269072).

However, in the case of the above-described treatment using a silicate, although the hydrophilicity is good, the hard silica is contained, so that the tool wear in forming the fin becomes large, and when the cooling operation is started. In this case, a faint odor peculiar to water glass is generated. Further, in the resin treatment containing silica fine particles, odor generation is small, but tool wear is large, and the contact angle of water droplets adhering to the surface increases, and the hydrophilicity decreases.

Further, a method of sequentially forming an acrylic resin layer and a cellulose resin layer on the surface of an aluminum material to improve hydrophilicity and corrosion resistance (Japanese Patent Publication No. Hei 4-24632), a method of preparing a water-soluble organic resin and a nonionic surfactant For forming a hydrophilic film having a thickness of 0.05 to 5 [mu] m (Japanese Unexamined Patent Publication (Kokai) No. Hei 4-316837), an organic hardener containing a melamine resin, a urea resin or a benzoguanamine resin as a hydrophilic organic compound. There is also a method of forming an added hydrophilic film (Japanese Patent Publication No. 5-15176).

Although these processing methods have the characteristics that tool wear is small and odor is hardly generated, the contact angle of water droplets adhering to the fin surface increases when cooling operation and heating operation are alternately repeated. Performance is reduced. Further, when a surfactant is used as in the technique described in JP-A-4-316837, problems such as uneven quality due to foaming and a decrease in productivity arise.
When the surfactant elutes, the hydrophilicity is significantly reduced. Furthermore, when the fin material for a heat exchanger is coated and used, degeneration and cracks may occur on the surface of the plastic drain pan due to dew condensation water or components eluted by the dew condensation water.

Therefore, a method of applying a mixed film obtained by adding polyacrylic acid, N-methylolacrylamide, polyethylene oxide and the like to a carboxymethylcellulose resin is applied to the surface of an aluminum material (JP-A-6-32255).
No. 2, Japanese Patent Application Laid-Open No. 7-102188), a method of forming a film containing an aqueous resin, if necessary, using polyglutamic acid and a basic compound as essential components (JP-A-7-102188).
A method of providing a mixed film of the above resin having a polyoxyalkylene chain and a specific aqueous resin (JP-A-7-1021)
No. 89), a method of mixing two or more water-soluble resins having different solubility parameters on an aluminum material to form a resin-based film having a finely roughened surface and maintaining a low contact angle ( JP-A-7-270092), a method in which an aqueous solution of carboxymethylcellulose and polyethylene glycol having a defined molecular weight is applied to the surface of an aluminum material (JP-A-8-261688), and the surface is finely roughened to form a contact angle. (Japanese Patent Laid-Open No. 7-27)
[0092] A method of forming a hydrophilic film having fine pores on the surface thereof using a mixture of an epoxy-based crosslinking agent having a defined molecular weight and a polyvinyl-based resin (JP-A-9-26288) has been proposed.

According to these techniques, it is possible to obtain the same excellent hydrophilicity as that obtained by a water glass treatment. In particular, Japanese Patent Application Laid-Open Nos.
In the technique described in JP-A-26288, since the surface morphology is roughened to a fine ground glass shape by a resin film, the fin material is excellent in hydrophilicity and is subjected to a conventional water glass treatment. There are almost no problems such as tool wear and odor. Further, it is epoch-making in that the durability of the hydrophilic property is improved.

[0012]

However, the long-term hydrophilicity of the fin material on which the above-mentioned resin film is formed is inferior to that of the fin material treated with water glass. An air conditioner may be operated for cooling for a long period of time, and condensed water is generated to gradually dissolve the resin film. For this reason, although short-term hydrophilic continuity can be obtained, excellent long-term hydrophilic continuity cannot be obtained in the long term.

The present invention has been made in view of the above problems, and provides a fin material for a heat exchanger having excellent long-term hydrophilicity retention while maintaining low odor characteristic of a resin-based treatment material. The purpose is to:

[0014]

A fin material for a heat exchanger according to the present invention comprises a corrosion-resistant film containing one of a chromate film and a zirconium-based film formed on the surface thereof, and a fin material formed on the corrosion-resistant film. A first hydrophilic resin film having irregularities on the surface at intervals of 10 μm or less;
A second hydrophilic resin film formed on the surface of the hydrophilic resin film having irregularities at intervals of 0.5 μm or less,
The second hydrophilic resin film contains a water-soluble resin and a zirconium compound in an amount of 0.1 to 100 parts by weight of the water-soluble resin.
It is characterized by being a mixture of 01 to 50 parts by weight.

The water-soluble resin has a hydroxyl group,
It is preferable that the compound has at least one functional group selected from the group consisting of an ester group, an amino group, a carboxyl group and an ether group in the molecule.

In the present invention, since the corrosion-resistant film is formed on the surface of the fin material for a heat exchanger, the corrosion resistance of the fin material can be improved. Further, a first hydrophilic resin film having irregularities provided on the surface at appropriate intervals is formed on the corrosion-resistant film, and an appropriate amount of a zirconium compound for a water-soluble resin is formed on the first hydrophilic resin film. Are mixed to form a second hydrophilic resin film having irregularities on the surface at appropriate intervals, so that the long-lasting hydrophilicity is improved and the water glass-based treatment film is formed. Such odor does not occur.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fin material for a heat exchanger according to the present invention will be described below. In the present invention, a chromate film or a zirconium-based film is used as a corrosion-resistant film formed on the surface of an aluminum material or the like. As the chromate film, for example, a phosphoric acid chromate film and a chromate chromate film can be used, and the surface of an aluminum material or the like may be subjected to a coating type chromate treatment to which a resin component is added. On the other hand, the zirconium-based coating can be formed by a reactive zirconium-based chemical conversion treatment or a coating-type zirconium treatment. The acryl-zirconium composite film can be formed by this coating type zirconium treatment.

The amount of the corrosion-resistant coating to be applied is not particularly limited as long as it is within the range where the corrosion resistance can be obtained. Therefore, the amount of the corrosion-resistant coating to be applied is 10% as the Cr equivalent value and the Zr equivalent value.
It is preferably from 60 to 60 mg / m ² .

In the first hydrophilic resin film formed on the corrosion-resistant film, irregularities are formed on the surface at intervals of 10 μm or less to obtain a contact angle equivalent to that of the water glass treatment, and the surface is roughened. ing. When the distance between the irregularities exceeds 10 μm,
The function of imparting hydrophilicity due to the uneven shape cannot be obtained. Therefore,
The distance between the irregularities formed on the surface of the first hydrophilic resin film is 10 μm or less. As the first hydrophilic resin film,
For example, a mixed film of an epoxy resin and a polyvinyl resin is used.

As a method for forming the first hydrophilic resin film, for example, a method of applying a mixture of an epoxy-based crosslinking agent and a polyvinyl-based resin, and a method of applying a mixture of high-molecular compounds having a defined solubility parameter are applied. And the like. As in the method described in JP-A-7-270092, there is a method in which a surface is roughened by using a blend of resins having greatly different molecular cohesion forces to form irregularities at intervals of 10 μm or less. Further, a method of applying a mixture of polyglutamic acid and a basic compound may be used.

[0021] In the second hydrophilic resin film formed on the first hydrophilic resin film, 0.01 to 50 parts by weight of a zirconium compound is mixed with 100 parts by weight of a water-soluble resin. Irregularities are formed at intervals of 0.5 μm or less and the surface is roughened. The water-soluble resin is not particularly limited as long as it is other than a thermosetting resin that inhibits the hydrophilicity of the first hydrophilic resin. For example, polyacrylic acid or a salt thereof having at least one functional group selected from the group consisting of a hydroxyl group, an ester group, an amino group, a carboxyl group and an ether group in the molecule, polymethacrylic acid, polyamide resin, polyacrylamide , Polyvinyl alcohol, cellulose resin, polyethylene glycol or various surfactants.

If the distance between the irregularities formed on the surface of the second hydrophilic resin film exceeds 0.5 μm, the shape becomes the same as that of the first hydrophilic resin film, and there is no effect of improving the hydrophilicity. Therefore, the interval between the irregularities formed on the surface of the second hydrophilic resin film is set to 0.5 μm or less.

The zirconium compound causes a crosslinking reaction between the first hydrophilic resin film and the second hydrophilic resin film, whereby irregularities are formed on the surface of the second hydrophilic resin film. If the mixing amount of the zirconium compound is less than 0.01 part by weight with respect to 100 parts by weight of the water-soluble resin, the crosslinking reaction does not sufficiently occur, and irregularities having an interval of 0.5 μm or less are not formed. On the other hand, if the mixing amount of the zirconium compound exceeds 0.5 parts by weight, the crosslinking reaction occurs excessively, and the interval between the irregularities exceeds 0.5 μm. Further, when the mixing amount exceeds 0.5 parts by weight, the amount of inorganic substances increases, so that tool wear occurs when hard fins are formed as in the case of the water glass-based treatment, and at the start of cooling, it is weak. Offensive odor is generated. Therefore, the mixing amount of the zirconium compound with respect to 100 parts by weight of the water-soluble resin is 0.01 to 50 parts by weight.

[0024]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples that fall outside the scope of the claims.

First, JIS having a plate thickness of 0.110 mm
A corrosion-resistant coating (first layer) shown in Table 1 below was laminated on the surface of an aluminum plate material of A1100 H22.

[0026]

[Table 1]

Incidentally, among the corrosion-resistant coatings in Table 1 above,
In the coating treatment of A2 and A3, the coating material was applied using a bar coater and baked at 200 ° C. for 20 seconds to form a coating. In the chromate treatment of A1 and A2, the amount of deposition was 20 mg / m ^{2 in} terms of Cr, and in the zirconium treatment of A3, the amount of deposition was 40 mg / m ^{2 in} terms of Zr.

Next, a first hydrophilic resin film (second layer) shown in Table 2 below was laminated on the first layer.

[0029]

[Table 2]

[0030] Of the hydrophilic resin films in Table 2 above, the amount of the film was 5000 mg for B1 and B2.
/ M ² and baked at 220 ° C. for 30 seconds to form a film. Further, in the water glass hydrophilic treatment of B3, the applied amount was set to 200 mg / m ^{2 in} terms of SiO ₂ ,
A film was formed by baking at 00 ° C. for 20 seconds.

Next, a second hydrophilic resin film (third layer) in which a zirconium compound was mixed with a water-soluble resin shown in Table 3 below was laminated on the second layer.

[0032]

[Table 3]

As the zirconium compound, zirconium oxide (ZrO ₂ ) having a solid content of about 12 to 14% by weight.
A zirconyl ammonium carbonate solution containing is used. The amount of the film was 5000 mg / m ² ,
A film was formed by baking for 2 seconds.

The combinations of the first to third layers are shown in Table 4 below.
Shown in

[0035]

[Table 4]

At this time, the average distance between the irregularities formed on the surface of the second layer and the surface of the third layer is shown in Table 5 below. In addition,
The average interval between the irregularities was measured using a scanning electron microscope (SEM).

[0037]

[Table 5]

In Table 4 above, the mixing amount of the zirconium compound is a ratio of parts by weight of zirconium oxide to 100 parts by weight of the water-soluble resin.

Next, the long-term hydrophilicity persistence and odor of the test material of the fin material thus produced were evaluated. Hereinafter, each evaluation method will be described.

For the long-term hydrophilicity persistence, the contact angle was measured after 70 steps of immersing in tap water (flow rate: 1 liter / minute) for 7 hours and drying at 80 ° C. for 17 hours. evaluated.

The odor was evaluated by spraying water on the test material by spraying and smelling the odor immediately after wetting. A sample having no odor was rated as O, and a sample having strong odor was rated as X. .

The results are shown in Table 6 below.

[0043]

[Table 6]

As shown in Table 6 above, in Examples 1 to 8, since a suitable surface treatment film was formed on the fin for a heat exchanger, the contact angle was 30 ° or less, and the long-term hydrophilic persistence was good. In addition, there was no odor.

On the other hand, in Comparative Example 9, an odor was generated because the water glass-based treatment film was formed as the second layer.

In Comparative Example 10, since the second hydrophilic resin film was not formed on the third layer, the contact angle exceeded 30 ° and the long-term hydrophilicity was poor.

In Comparative Example 11, since the amount of the zirconium compound mixed in the second hydrophilic resin film is less than the lower limit of the range of the present invention, the distance between the irregularities formed on the surface exceeds the upper limit of the range of the present invention. , Poor long-term hydrophilicity persistence.

On the other hand, in Comparative Example 12, since the amount of the zirconium compound mixed in the second hydrophilic resin film exceeded the upper limit of the range of the present invention, the crosslinking reaction was excessive and the unevenness formed on the surface was reduced. The interval has exceeded the upper limit of the range of the present invention. For this reason, long-term hydrophilicity persistence was inferior. Further, an odor was generated in the same manner as when the water glass-based treatment film was formed.

In Comparative Example 13, the distance between the irregularities formed on the surface of the first hydrophilic resin film formed as the second layer exceeded the upper limit of the range of the present invention.

[0050]

As described above, according to the present invention,
The heat exchanger fin material has a three-layer structure in which a corrosion-resistant film and an appropriate hydrophilic resin film are laminated on the surface, so that the low odor characteristic of the resin-based surface treatment material can be maintained, and the heat treatment fin material can have a long odor. Excellent hydrophilicity retention over a period.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a contact angle of a water droplet on a plane.

FIG. 2 is a schematic diagram illustrating a heat exchange unit of the heat exchanger.

FIGS. 3A and 3B are schematic diagrams showing the state of attachment of water droplets on the fin surface, where FIG. 3A shows a case where hydrophilicity is good, FIG. 3B shows a case where hydrophilicity is poor, and FIG. .

[Explanation of symbols]

 1; planes 2, 6, 8, 11; water drops 3, 5, 7, 9, 10; fins 4; copper tube 22;

Claims (2)

[Claims] 1. A first anti-corrosion film formed on a surface of the anti-corrosion film and containing one of a chromate film and a zirconium-based film, and a first hydrophilic film formed on the anti-corrosion film and having irregularities on the surface at intervals of 10 μm or less. A second hydrophilic resin film formed on the first hydrophilic resin film, the second hydrophilic resin film having irregularities on the surface at intervals of 0.5 μm or less; A fin material for a heat exchanger, wherein a water-soluble resin is mixed with a zirconium compound in an amount of 0.01 to 50 parts by weight based on 100 parts by weight of the water-soluble resin. 2. The water-soluble resin has at least one functional group selected from the group consisting of a hydroxyl group, an ester group, an amino group, a carboxyl group and an ether group in the molecule. The fin material for heat exchange according to claim 1.