JPH04335992A - Aluminum fin material with mildewproofness - Google Patents

Abstract

PURPOSE:To provide an aluminum fin material for a heat exchanger, in which a problem of mildew in a fin and a drain is overcome and hydrophilic properties are held. CONSTITUTION:An aluminum fin material having mildewproofness, wherein a hydrophilic organic resin film containing silver powder and water dispersive silica is formed on an aluminum material.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum fin material for heat exchangers that has excellent hydrophilicity and anti-mold properties.

0002

2. Description of the Related Art In general, in a heat exchanger, particularly in an evaporator of an air conditioner, the surface temperature of the fins is below the dew point of the atmosphere, so water droplets adhere to the fin surfaces. Due to the adhesion of such water droplets, ventilation resistance increases and the air volume decreases, resulting in a decrease in heat exchange efficiency. Heat exchange efficiency is greatly influenced by the water wettability of the fin surface.If the fin surface has good wettability, attached water is less likely to form droplets, which reduces ventilation resistance and increases air volume, increasing heat exchange efficiency. increase It has been devised to perform such hydrophilic surface treatments on aluminum strips, and treatments such as boehmite treatment, silicate treatment, silica sol treatment, and mixing treatment with hydrophilic organic polymers and silicate compounds have been carried out.

[0003] In recent years, houses have become more airtight, making condensation more likely to occur, and changes in lifestyles, such as installing carpets on the floors, are creating an environment in which bacteria and mold can easily breed. This mold and bacteria move through the airflow circulating indoors and grow on the surface of the heat exchanger's surface-treated aluminum fins and in the drain water, giving the indoor air a musty odor and causing mold to clog the drain water. or

0004

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an aluminum fin material for heat exchangers that overcomes the problem of mold growth in fins and drains and retains hydrophilicity.

[0005]

[Means for Solving the Problems] As a result of various studies to achieve the above object, the present inventors have found that by mixing copper powder together with silica into the hydrophilic organic resin film of the aluminum fin material, the hydrophilic organic resin film of the aluminum fin material becomes hydrophilic. It was discovered that the antifungal properties could be improved without impairing the properties, and based on this knowledge, the present invention was accomplished. That is, the present invention provides an aluminum fin material having mold-proof properties, which is formed by forming a hydrophilic organic resin film containing copper powder and water-dispersible silica on an aluminum material.

According to the fin material of the present invention, an antifungal agent containing copper powder as a main ingredient is mixed into a hydrophilic coating containing water-dispersible silica, thereby imparting antifungal properties to the coating film and at the same time providing antifungal properties to the hydrophilic coating containing water-dispersible silica. Copper ions are eluted over time, suppressing the growth of mold and bacteria not only in the fins but also in the drain water. Further, as described later, by controlling the mixing ratio of the hydrophilic organic resin and the antifungal agent and the thickness of the hydrophilic film containing the antifungal agent, hydrophilicity and coatability are not inhibited.

As the water-dispersible silica used in the present invention, alkali silicates such as sodium silicate and potassium silicate, or silica sol (colloidal silica) are used, and the particle size thereof is usually 1 to 100 μm, preferably 1 to 100 μm. 5-20μm
It is. As the hydrophilic organic resin, acrylic resin, epoxy resin, urea resin, etc. are used. Particle size of copper powder is 1μ
It is preferable to use fine copper powder of about 1.0 m. In addition, as the antifungal agent, organic antifungal agents and inorganic antifungal agents such as zeolite are preferred as they are highly safe and effective. It is of course possible to add one of these antifungal agents alone, but 2
It is more effective to use a mixture of two or more species. Furthermore, in order to further increase hydrophilicity, it is also possible to use nonionic, anionic, or cationic surfactants. The content of copper powder in the antifungal agent is usually 0.5% or more, preferably 3 to 30%.

By the way, in general, when a fungicide is mixed into a hydrophilic film, hydrophilicity is inhibited, but in the present invention, the mixing ratio of water-dispersible silica and hydrophilic resin is 3. :1 to 1:1.5, and the mixing ratio of the antifungal agent to the hydrophilic resin is in the range of 3:97 to 30:70 by weight.A fin material with excellent hydrophilicity and antifungal properties. succeeded in forming. If the amount of organic resin is not within this range, the balance of the hydrophilic film will be poor, resulting in a decrease in hydrophilicity. Also,
If the amount of the antifungal agent is less than this range, a sufficient antifungal effect will not be obtained, and if it is more than this range, not only will the stability of the paint deteriorate, but also the hydrophilicity will decrease. In the present invention, water-dispersible silica has the effect of improving hydrophilicity and corrosion resistance, and if it is too small, the hydrophilicity and corrosion resistance deteriorate,
If the amount is too large, workability will decrease.

[0009] In addition, the hydrophilic film containing the antifungal agent has S in the film.
It is desirable that the i amount is 50 mg/m2 to 350 mg/m2. If the coating amount is less than this range, a sufficient anti-mildew effect cannot be obtained, and if it is greater than this range, fin moldability will be affected. In the present invention, an aluminum strip is preferably used as the aluminum material, and the above-mentioned hydrophilic film is formed on the aluminum strip after it is usually subjected to a surface treatment. Although there are no particular restrictions on the surface treatment, ordinary chromic acid chromate treatment is preferably performed.

0010

EXAMPLES Next, the present invention will be explained in more detail based on examples.

Example: An industrial pure aluminum strip with a thickness of 0.105 mm was continuously degreased and chemically treated, and water-dispersible colloidal silica particles with a particle size (average) of 10 μm, a hydrophilic acrylic resin, and a fungicide were added thereto. copper powder, or copper powder and TBZ (manufactured by Hokuko Chemical Co., Ltd.,
The solid content ratio of colloidal silica: hydrophilic acrylic resin: fungicide is 45:
Apply the paint mixed in the ratio of 45:8 and heat it at 200℃ for 15 minutes.
Bake drying was performed for seconds. The amount of coating depends on the amount of Si in the film.
The amount was set at 150 mg/m2. As the copper powder, C-100 (average particle size 1 μm) manufactured by Kyoto Elex Co., Ltd. was used. In this way, sample no. I got 1.

Next, as shown in Table 1 below, sample No. 2 to 8 were created.

[0013]

[Table 1]

These sample No. Tests Nos. 1 to 8 were tested for hydrophilicity, mold resistance, workability, and drain mold resistance as follows, and the results are shown in Table 2.

[0015]

[Table 2]

From these results, it can be seen that the products of the present invention are excellent in all of hydrophilicity, mildew resistance, and processability, but the comparative examples are poor in at least one of the items.

[0017]

Effects of the Invention As explained above, in the present invention, fine copper powder is used as a fungicide, and the mixing ratio of water-dispersible silica, hydrophilic organic resin, and fungicide in the hydrophilic film is controlled. Hydrophilic properties can be achieved by setting the hydrophilic film thickness within an appropriate range.
It is possible to obtain an aluminum fin material for a heat exchanger with excellent mold resistance without impairing workability.

Claims (4)

[Claims] 1. An aluminum fin material having mildew resistance, which is formed by forming a hydrophilic organic resin film containing copper powder and water-dispersible silica on an aluminum material. 2. The aluminum fin material according to claim 1, wherein the hydrophilic organic resin film contains one or more fungicides. 3. The aluminum fin material according to claim 2, wherein the ratio of the sum of the copper powder and the antifungal agent to the hydrophilic organic resin film is in the range of 3:97 to 30:70 by weight. 4. The aluminum fin material according to claim 1, wherein the coating amount of the hydrophilic organic resin film is in the range of 50 to 350 mg/m2 in terms of Si content.