JP5586834B2 - Aluminum fin material for heat exchanger - Google Patents

Description

  The present invention relates to an aluminum fin material made of aluminum or an aluminum alloy having a coating film formed on the surface thereof, and more particularly to an aluminum fin material for a heat exchanger that is preferably used for a fin material of a heat exchanger such as an air conditioner.

  Heat exchangers are used in various fields such as room air conditioners, packaged air conditioners, refrigeration showcases, refrigerators, oil coolers, and radiators. In heat exchangers such as room air conditioners and packaged air conditioners, aluminum material is used for the fin material because of its excellent thermal conductivity and workability.

  In addition, in the heat exchanger, the dew condensation water fin material prevents the dew condensation water during the cooling operation from staying between the fins (fin material), resulting in resistance during blowing and degrading the heat exchanger characteristics. For the purpose of increasing the fluidity on the surface, the surface of the fin material is subjected to a hydrophilic treatment. Furthermore, for the purpose of preventing the occurrence of corrosion of the fin material, the surface of the fin material is also subjected to a corrosion resistance treatment.

  However, when the fin material having the above-described configuration is used in a high-temperature and high-humidity environment, particularly in an environment where there is a large amount of dust or dust, mold or bacteria propagate by using dust or dust attached to the surface of the fin material as a nutrient source. Therefore, it has a problem of generating an unpleasant odor.

In order to solve the above problems, conventionally, an aluminum fin material having the following configuration has been proposed in Patent Document 1 for the purpose of suppressing the growth of mold or bacteria while having excellent hydrophilicity. The aluminum fin material of Patent Document 1 includes a substrate made of aluminum or an aluminum alloy, a corrosion-resistant film made of any one of an inorganic oxide, an organic-inorganic composite compound, and an organic polymer compound formed thereon, and An antibacterial agent formed on the surface and a hydrophilic film composed of a hydrophilic composite compound (composite compound of an organic polymer substance and an inorganic compound) or a hydrophilic mixed resin, and a hydroxyl group in the molecule formed thereon And a water-soluble resin film.
JP 2006-78134 A

  However, the conventional aluminum fin material has the following problems. In the aluminum fin material of Patent Document 1, in order to improve the hydrophilicity of the hydrophilic film and the water-soluble resin film, both films contain an organic substance such as a surfactant or a low-molecular water-soluble substance. When this organic substance is eluted in the dew condensation water (drain water) and stays in the drain pan of the air conditioner, there is a problem that an unpleasant odor is generated due to a hotbed where mold or bacteria are generated.

  The air conditioner may be operated at a slightly higher temperature than the dew point so that drain water is not generated as much as possible. In such a case, there is almost no generation of drain water. Therefore, the organic matter eluted in the drain water does not stay in the drain pan and is washed away. Moreover, if there is little production | generation of drain water, the dust or dust adhering to the fin material surface of a heat exchanger will not be washed off with drain water, but will remain on the fin material surface. There is also a problem that the dust or dust falls and accumulates in a drain pan or the like, and becomes a hotbed where mold or bacteria are generated, resulting in an unpleasant odor.

  This invention is made | formed in view of the said problem, and it aims at providing the aluminum fin material for heat exchangers which can prevent generation | occurrence | production of the unpleasant odor by a mold | fungi or bacteria over a long period of time.

In order to solve the above-mentioned problems, an aluminum fin material for a heat exchanger according to claim 1 is a substrate made of aluminum or an aluminum alloy, and a base made of an inorganic oxide or an organic-inorganic composite compound formed on the substrate. A water-soluble resin having a hydroxyl group in the molecule is formed with respect to 100 parts by mass of polyacrylic acid or polyacrylic acid salt formed on the treatment layer and the base treatment layer in a thickness of 0.1 to 10 μm. A water-soluble resin layer comprising a hydrophilic coating layer comprising a hydrophilic resin containing 100 parts by mass, and a water-soluble resin formed on the hydrophilic coating layer with a film thickness of 0.1 to 10 μm and having a hydroxyl group in the molecule. and a coating layer, wherein the water-soluble coating layer, which contains zinc pyrithione as antibacterial agents, said heat exchanger aluminum fin material when immersed for 24 hours in running water at 20 ° C., prior to The zinc pyrithione elutes 50% or more, and the water-soluble coating layer contains polyethylene glycol having a mass average molecular weight of less than 100,000, and the content of the polyethylene glycol excludes zinc pyrithione of the water-soluble coating layer. The ratio of the resin component is 50% by mass or more.

  According to the above configuration, the hydrophilic coating layer is made of a predetermined hydrophilic resin, and the water-soluble coating layer is made of a predetermined water-soluble resin, whereby the hydrophilicity of the aluminum fin material is increased and its durability is maintained. And the fluidity of drain water on the surface of the aluminum fin material is improved. Accordingly, even if dust or dirt adheres to the surface of the aluminum fin material, it is easily washed away with drain water, and dust or dirt does not remain in the drain pan. Therefore, the occurrence of mold or bacteria in the drain pan is sufficiently suppressed.

In addition, the water-soluble coating layer contains zinc pyrithione as an antibacterial agent having a predetermined solubility, that is, easily soluble in water, and when the aluminum fin material is immersed in flowing water, a predetermined amount of zinc pyrithione is eluted, so that the aluminum fin material Zinc pyrithione dissolves quickly into the drain water from the surface, and the drain pan is covered with zinc pyrithione . Therefore, even when the air conditioner is in an operating state where only a very small amount of drain water is generated and substances (organic matter, dust, dust) that become a hotbed for mold or bacteria generation are difficult to be discharged, mold or bacteria in the drain pan Occurrence is sufficiently suppressed. Furthermore, when the water-soluble coating layer contains a predetermined amount of polyethylene glycol, the water-soluble resin constituting the water-soluble coating layer is likely to elute into the drain water, thereby containing it in the water-soluble coating layer. Zinc pyrithione is easily eluted in the drain water. For this reason, since only a very small amount of drain water is generated, mold or bacteria generation in the drain pan is sufficiently suppressed even when the air conditioner is in an operating state in which substances that become a hotbed for mold or bacteria generation are difficult to be discharged.

  The aluminum fin material for a heat exchanger according to claim 2 is characterized in that the hydrophilic coating layer contains an antibacterial agent having a solubility in pure water at 20 ° C. of 1 mg / 100 ml or less.

  According to the above configuration, the antibacterial agent does not dissolve in the drain water but remains in the aluminum fin material by containing the antibacterial agent that has a predetermined solubility in the hydrophilic coating layer, that is, not easily dissolved in water. Therefore, mold or bacteria generation on the aluminum fin material surface is sufficiently suppressed.

  According to the aluminum fin material for a heat exchanger according to the present invention, by providing a predetermined hydrophilic coating layer and a water-soluble coating layer containing an antibacterial agent, generation of unpleasant odor due to mold or bacteria over a long period of time is prevented. it can. Also, the hydrophilic coating layer contains an antibacterial agent, the water-soluble coating layer contains a predetermined amount of polyethylene glycol, or the water-soluble coating layer contains zinc pyrithione, and a predetermined amount of the zinc pyrithione By elution, generation of unpleasant odor due to mold or bacteria can be further prevented.

An embodiment of an aluminum fin material for a heat exchanger according to the present invention will be described with reference to the drawings. 1A and 1B are cross-sectional views schematically showing a cross section of an aluminum fin material for heat exchanger (hereinafter referred to as a fin material).
<Fin material>
As shown in FIG. 1A, the fin material 1 includes a substrate 2, a base treatment layer 3 formed on the substrate 2, and a hydrophilic coating layer 4 formed on the base treatment layer 3. And a water-soluble coating layer 5 formed on the hydrophilic coating layer 4. Here, the top of the substrate 2 means one side or both sides (not shown) of the substrate 2. Each configuration will be described below.

(substrate)
The substrate 2 is a plate material made of aluminum or an aluminum alloy, and since it has excellent thermal conductivity and workability, 1000 series aluminum defined by JIS H4000, preferably aluminum of alloy number 1200 is used. In addition, in the aluminum fin material for heat exchangers, those having a thickness of about 0.08 to 0.3 mm are used in consideration of strength, thermal conductivity, workability, and the like.

(Undercoat layer)
The base treatment layer 3 is made of an inorganic oxide or an organic-inorganic composite compound. The inorganic oxide preferably contains chromium (Cr) or zirconium (Zr) as a main component, and is formed by, for example, phosphoric acid chromate treatment, zirconium phosphate treatment, or chromate chromate treatment. . However, the present invention is not limited to this as long as it exhibits corrosion resistance. For example, the base treatment layer 3 can also be formed by performing zinc phosphate treatment or phosphate titanate treatment. The organic-inorganic composite compound is formed by performing a coating type chromate treatment or a coating type zirconium treatment, and examples thereof include an acryl-zirconium composite.

The base treatment layer 3 preferably contains Cr or Zr in the range of 1 to 100 mg / m ^2. The thickness of the base treatment layer 3 is preferably 10 to 1000 mm, but the purpose of use, etc. Needless to say, it can be changed as appropriate. The formation of the base treatment layer 3 improves the adhesion between the substrate 2 and a hydrophilic coating layer 4 to be described later, and imparts corrosion resistance to the fin material 1.

(Hydrophilic coating layer)
The hydrophilic coating layer 4 is formed with a film thickness of 0.1 to 10 μm on the base treatment layer 3, and with respect to polyacrylic acid or polyacrylate (hereinafter, both are referred to as polyacrylic acids), It consists of a hydrophilic resin containing a predetermined amount of a water-soluble resin having a hydroxyl group in the molecule. Here, the polyacrylate is specifically a sodium salt, a potassium salt, an ammonium salt or the like.

  The polyacrylic acid constituting the hydrophilic coating layer 4 (hydrophilic resin) becomes a water-insoluble coating layer by coating and baking, but it is not hydrophilic. These polyacrylic acids were originally used for the purpose of imparting adhesiveness or imparting water resistance as a binder resin for a coating film layer. The polyacrylic acid is made to contain a predetermined amount of a water-soluble resin having a hydroxyl group, and the hydrophilic coating layer 4 having strong adhesion is formed by, for example, coating and baking. This is because polyacrylic acids originally have a high adhesion improving effect, and esterification by a dehydration condensation reaction between a hydroxyl group and a carboxyl group occurs in the hydrophilic coating layer 4 partially simultaneously. This is because a strong coating layer is formed. Thus, by making it a coating film layer with high adhesiveness, melt | dissolution to the drain water of the water-soluble resin containing a hydroxyl group can be suppressed, and hydrophilic sustainability can be provided to the hydrophilic coating film layer 4. FIG. Moreover, since the hydrophilic property of the hydrophilic coating film layer 4 is maintained, dust or dust adhering to the surface of the fin material 1 is easily washed away by the drain water.

  The water-soluble resin contained in the polyacrylic acid in a predetermined amount is not particularly limited as long as it has a hydroxyl group in the molecule, and examples thereof include sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene glycol. Moreover, water-soluble resin may be used independently, or 2 or more types may be mixed and used for it.

  As a blending ratio of the hydrophilic resin, the total of the water-soluble resin having a hydroxyl group in the molecule needs to be in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the polyacrylic acids. The reason for limiting the numerical value of this blending ratio is as follows. If the content of the water-soluble resin is less than 1 part by mass, the hydrophilicity of the hydrophilic coating layer 4 cannot be obtained at all. Moreover, when content of water-soluble resin exceeds 100 mass parts, the melt | dissolution component which melt | dissolves in drain water will increase, and the hydrophilic sustainability of the fin material 1 (hydrophilic coating film layer 4) will fall. As a result, dust or dust easily adheres to the surface of the fin material 1 and becomes a hotbed where mold or bacteria are generated.

The reason for limiting the numerical value of the film thickness (0.1 to 10 μm) of the hydrophilic coating film layer 4 is as follows.
If the film thickness is less than 0.1 μm, the hydrophilicity of the hydrophilic coating layer 4 is lowered. Moreover, when a film thickness exceeds 10 micrometers, the applicability | paintability in the case of formation (for example, application baking) of a coating-film layer will fall. In addition, a film thickness exceeding 10 μm is not preferable economically.

(Water-soluble coating layer)
The water-soluble coating layer 5 is formed on the hydrophilic coating layer 4 with a film thickness of 0.1 to 10 μm, and is made of a water-soluble resin having a hydroxyl group in the molecule and has a predetermined solubility. 6 is contained. The reason why the water-soluble coating layer 5 is formed on the hydrophilic coating layer 4 is as follows.

  Since the hydroxyl group of the water-soluble resin constituting the water-soluble coating layer 5 and the carboxyl group of the polyacrylic acid constituting the hydrophilic coating layer 4 cause esterification by a dehydration condensation reaction, the water-soluble coating layer 5 and the hydrophilic coating layer 4 are partially bonded. As a result, the drain water generated during the cooling operation dissolves most of the water-soluble coating layer 5, but the water-soluble coating layer 5 remains slightly on the hydrophilic coating layer 4. It becomes possible to improve the hydrophilic durability of 1 (hydrophilic coating layer 4).

  Moreover, since the hydrophilic coating film layer 4 is comprised from the hydrophilic resin containing polyacrylic acid, it becomes a coating film layer with high adhesiveness. And the fin material 1 is manufactured by processing the board | plate material in which the coating-film layer was formed in the surface. Therefore, if the adhesiveness of the coating layer is high, in manufacturing the fin material 1, when the plate material is made into a coil shape, the plate materials adhere to each other, or when the fin is processed from the plate material, the plate material adheres to the mold. It is easy to cause adhesion failure. In the present invention, the water-soluble coating layer 5 is formed on the hydrophilic coating layer 4 in order to suppress the adhesiveness of the hydrophilic coating layer 4.

  The water-soluble resin constituting the water-soluble coating layer 5 is not particularly limited as long as it has a hydroxyl group in the molecule. The water-soluble resin is preferably a resin having a high solubility in pure water because the water-soluble coating layer 5 is preferably one that can be sufficiently eluted in the drain water. Specific examples include polyvinyl alcohol, sodium or potassium salt of carboxymethyl cellulose, polyethylene glycol, or urethane-modified compounds thereof. In addition, when using polyvinyl alcohol as a water-soluble resin, it is preferable to use the partial saponification type (saponification degree 80% or less) which is easy to elute in drain water.

  The water-soluble coating layer 5 may be composed of one type of the water-soluble resin or may be composed of a mixed resin obtained by mixing two or more types of water-soluble resins. When the antibacterial agent 6 contained in the water-soluble coating layer 5 is zinc pyrillion, when the fin material 1 is immersed in running water for 24 hours, zinc pyrithione is eluted by 50% or more. It is preferable to be composed of a water-soluble resin. Examples of such a water-soluble resin include a sodium salt or potassium salt of carboxymethyl cellulose, a resin containing polyethylene glycol, and the like.

  When using water-soluble resin containing polyethylene glycol, the weight average molecular weight of polyethylene glycol is less than 100,000, and the content of polyethylene glycol in the water-soluble coating layer 5 is water-soluble coating. The proportion of the resin component excluding the antibacterial agent 6 (zinc pyrithione) of the layer 5 is preferably 50% by mass or more, and more preferably 60 to 90% by mass. This is because polyethylene glycol having a mass average molecular weight of less than 100,000 is easily eluted in the drain water, and since this is contained in the water-soluble resin by 50% by mass or more, the water-soluble resin is easily eluted in the drain water. This is because zinc pyrithione is surely easily eluted from the water-soluble coating film layer 5. As a result, generation of mold or bacteria in the drain pan is further suppressed.

  The reasons for limiting the numerical value of the film thickness (0.1 to 10 μm) of the water-soluble coating layer 5 are as follows. When the film thickness is less than 0.1 μm, an adhesion failure occurs when the fin material 1 is manufactured, and the effect of improving the hydrophilic sustainability of the fin material 1 (hydrophilic coating layer 4) is lost. On the other hand, when the film thickness exceeds 10 μm, the coating property during the formation of the coating layer (for example, coating and baking) is reduced, and the antibacterial agent 6 contained in the water-soluble coating layer 5 is drained. Elution is suppressed and mold or bacteria generation in the drain pan cannot be suppressed. In addition, a film thickness exceeding 10 μm is not preferable economically.

  The antibacterial agent 6 contained in the water-soluble coating layer 5 uses an antibacterial agent 6 having a solubility in pure water of 20 ° C. of 1 to 2000 mg / 100 ml, that is, easily soluble in water. By using such an antibacterial agent 6 that is easily dissolved in water, the antibacterial agent 6 quickly dissolves in the drain water and covers the drain pan, so that the antifungal property of the drain pan is improved. Examples of such antibacterial agent 6 include zinc pyrithione, chlorxylenol, thiabendazole, methyl isothiazoline and the like.

  The reasons for limiting the numerical value of the solubility of the antibacterial agent 6 are as follows. When the solubility is less than 1 mg / 100 ml, the antibacterial agent 6 hardly dissolves into the drain water from the surface of the fin material 1 (water-soluble coating layer 5), and the drain pan is not covered with the antibacterial agent 6. Can not control mold or bacteria generation in In addition, when the solubility exceeds 2000 mg / 100 ml, it dissolves faster in the drain water than the organic substances (surfactant or low molecular water-soluble substances, etc.) contained in the coating layer, and is discharged without staying in the drain pan. End up. Therefore, mold or bacteria generation in the drain pan cannot be suppressed.

  The content of the antibacterial agent 6 is preferably 1 to 50% by mass with respect to the total mass of the water-soluble coating layer 5. When the content is less than 1% by mass, the antifungal antibacterial property tends to be lowered, and when the content exceeds 50% by mass, the hydrophilicity of the coating layer tends to be lowered.

  The fin material 1 according to the present invention has a hydrophilic coating layer 4, a water-soluble coating layer 5, and an antibacterial agent 6 contained in the coating layer containing alumina, silica, titania, zeolite, alkali silicate, and It is preferable not to contain impurities such as these hydrates. Moreover, it is preferable that the total amount of at least one of alumina, silica, titania, zeolite, alkali silicate and hydrates contained as impurities in the fin material 1 is 1% by mass or less. When impurities are contained in excess of 1% by mass, these impurities tend to adsorb or occlude dust or dust, generate unpleasant odors, and make the fin material surface water repellent (hydrophilicity lowered). If the hydrophilic coating layer 4 and the water-soluble coating layer 5 contain impurities, it is not a continuous coating layer, so the effect of washing off dust or dust is weakened.

The total amount of impurities is measured as follows, for example. First, the hydrophilic coating film layer 4 and the water-soluble coating film layer 5 are peeled from the substrate 2 (the base treatment layer 3) using fuming nitric acid or the like. Both peeled coating layers are completely burned, and the residue is poured into pure water. And the mass of the insoluble matter which does not melt | dissolve in a pure water is measured, and it is set as the total amount of an impurity.

<Another embodiment of the fin material>
As shown in FIG.1 (b), it is preferable that 1 A of fin materials contain the antimicrobial agent 7 in which the hydrophilic coating film layer 4 has predetermined | prescribed solubility. About another structure, since it is the same as that of the fin material 1 (refer Fig.1 (a)), description is abbreviate | omitted.

  As the antibacterial agent 7 contained in the hydrophilic coating layer 4, an antibacterial agent 7 having a solubility in pure water at 20 ° C. of 1 mg / 100 ml or less, that is, hardly soluble in water is used. By using the antibacterial agent 7 that hardly dissolves in water, the antibacterial agent 7 remains in the fin material 1 (hydrophilic coating layer 4) without eluting into the drain water. The antifungal property of the coating layer 4) is maintained. Examples of the antibacterial agent 7 include copper pyrithione and carbendazine (BCM).

  The reason for limiting the numerical value of the solubility of the antibacterial agent 7 is as follows. When the solubility exceeds 1 mg / 100 ml, the antibacterial agent 7 dissolves into the drain water from the hydrophilic coating layer 4, and the amount of the antibacterial agent 7 in the hydrophilic coating layer 4 decreases, so that the fin material 1 (hydrophilic The antibacterial and antifungal properties of the coating layer 4) tend to decrease.

  The content of the antibacterial agent 7 is preferably 1 to 50% by mass with respect to the total mass of the hydrophilic coating layer 4. When the content is less than 1% by mass, the antifungal antibacterial property tends to be lowered, and when the content exceeds 50% by mass, the hydrophilicity of the coating layer tends to be lowered.

  Note that the antibacterial agent 6 contained in the water-soluble coating layer 5 and the antibacterial agent 7 contained in the hydrophilic coating layer 4 have different antifungal effects. That is, the antibacterial agent 6 contained in the water-soluble coating layer 5 elutes in the dew condensation water (drain water) and obtains the antibacterial and antibacterial effect such as air-conditioning drain pan. Unlike the antibacterial agent 6, the contained antibacterial agent 7 has a fungicidal antibacterial effect on the surface of the fin material.

Next, the manufacturing method of the fin material 1 (refer FIG. 1A) which concerns on this invention is demonstrated. The fin material 1 is manufactured by the following method.
<Fin material manufacturing method>
(1) A base treatment made of an inorganic oxide or an organic-inorganic composite compound by performing phosphoric acid chromate treatment, zirconium phosphate treatment or the like on one or both surfaces (not shown) of a substrate 2 made of aluminum or an aluminum alloy. Layer 3 is formed. Here, the phosphoric acid chromate treatment, the zirconium phosphate treatment, and the like are performed by applying a chemical conversion treatment solution to the substrate 2 by spraying or the like. The coating amount is preferably 1 to 100 mg / m ^{2 in} terms of Cr or Zr, and the formed film thickness is preferably 10 to 1000 mm. In addition, before forming the base treatment layer 3, it is preferable to degrease the surface of the substrate 2 in advance by spraying an alkaline aqueous solution on the surface of the substrate 2. The adhesion between the substrate 2 and the base treatment layer 3 is improved by degreasing.

(2) A resin solution of polyacrylic acid (hydrophilic resin) containing a predetermined amount of water-soluble resin is applied and baked on the formed base treatment layer 3, and hydrophilicity is formed on the base treatment layer 3. A coating layer 4 is formed. Here, application | coating is performed by conventionally well-known application methods, such as a bar coder and a roll coater, and an application quantity is suitably set so that the thickness of the hydrophilic coating film layer 4 may be set to 0.1-10 micrometers.

  The baking temperature is preferably 200 ° C. or higher. When the temperature is lower than 200 ° C., the dehydration condensation reaction between the carboxyl group of the polyacrylic acid constituting the hydrophilic coating layer 4 and the hydroxyl group of the water-soluble resin hardly occurs, and the amount of the water-soluble resin dissolved in the drain water increases. In addition, the hydrophilic durability of the fin material 1 (hydrophilic coating layer 4) is lowered. As a result, dust or dust tends to adhere to the surface of the fin material 1. Although the upper limit of the baking temperature is not particularly limited, in practice, when baking is performed at a high temperature exceeding 300 ° C., the hydrophilic coating layer 4 is thermally decomposed and easily causes problems such as yellowing. Therefore, it is practical that the temperature is 300 ° C. or lower. And, like the fin material 1A (see FIG. 1B), when the hydrophilic coating layer 4 contains the antibacterial agent 7, the antibacterial agent 7 is decomposed and the antibacterial and antibacterial properties are reduced. It becomes easy.

  Furthermore, before forming the hydrophilic coating layer 4, it is preferable to degrease the surface of the base treatment layer 3 in advance by spraying an alkaline aqueous solution onto the surface of the base treatment layer 3. Degreasing improves adhesion between the base treatment layer 3 and the hydrophilic coating layer 4.

(3) A resin solution of a water-soluble resin is applied to the surface of the formed hydrophilic coating layer 4 and baked to form a water-soluble coating layer 5 on the hydrophilic coating layer 4 to obtain a fin material. Set to 1. Here, application | coating is performed by conventionally well-known application methods, such as a bar coder and a roll coater, and an application quantity is suitably set so that the thickness of the water-soluble coating-film layer 5 may be set to 0.1-10 micrometers. The baking temperature is appropriately set depending on the resin solution to be applied, but is performed at a baking temperature at which the antibacterial agent 6 contained in the water-soluble coating layer 5 is not decomposed.

  Moreover, it is preferable to wash the surface of the hydrophilic coating layer 4 with water before forming the water-soluble coating layer 5. By washing the surface of the hydrophilic coating layer 4 with water, organic substances (surfactant or low-molecular water-soluble substance) contained in the hydrophilic resin constituting the hydrophilic coating layer 4 are removed. As a result, it is possible to prevent these organic substances from being dissolved in the drain water, and the dissolved organic substance becomes a hotbed for generation of mold or bacteria, thereby generating an unpleasant odor.

Although the best mode for carrying out the present invention has been described above, examples in which the effects of the present invention have been confirmed will be described below.
( Reference Examples 1 and 2)
In order to confirm the effect of the present invention, a fin material 1 shown in FIG. And the board | substrate 2 used the aluminum plate with a plate | board thickness of 0.1 mm which consists of aluminum of the alloy number 1200 prescribed | regulated to JISH4000.

A phosphoric acid chromate treatment for forming the base treatment layer 3 was performed on one surface of the aluminum plate. As the chemical conversion treatment liquid, Alsurf (registered trademark) 401/45, phosphoric acid, and chromic acid manufactured by Nippon Paint Co., Ltd. were used. At this time, the film thickness of the base treatment layer 3 was 400 mm (Cr conversion value measured by the fluorescent X-ray method was 20 mg / m ² ).

  Then, a predetermined amount of a hydrophilic resin resin solution containing 30 parts by mass of sodium carboxymethyl cellulose (average polymerization degree 500) is applied to 100 parts by mass of polyacrylic acid (average polymerization degree 400) on the base treatment layer 3. Then, baking was performed. The baking temperature was 220 ° C. at the temperature reached by the aluminum plate. In this way, a hydrophilic coating film layer 4 having a thickness of 1 μm was formed. After forming the hydrophilic coating layer 4, the surface was washed with running water for 5 seconds.

Then, a predetermined amount of an aqueous resin solution of polyvinyl alcohol (average polymerization degree 1200, saponification degree 75%) containing a predetermined amount of antibacterial agent 6 is applied onto the washed hydrophilic coating layer 4 and then baked. It was. The baking temperature was 150 ° C. at the temperature reached by the aluminum plate. In this way, a water-soluble coating film layer 5 having a thickness of 0.3 μm was formed, and a fin material 1 ( Reference Example 1) was manufactured. As antibacterial agent 6, zinc pyrithione (solubility: 1.5 mg / 100 ml) was used. The amount of zinc pyrithione (antibacterial agent 6) added was 2% by mass relative to the total mass of the water-soluble coating layer 5.
Further, in the hydrophilic coating layer 4 of the fin 1 ( Reference Example 1), 1% by mass of BCM (solubility: insoluble in water) as an antibacterial agent 7 is added to the resin solid content of the hydrophilic coating layer 4; Fin material 1A ( Reference Example 2) was produced.

(Example 3)
In Example 3, a mixed resin (resin ratio of polyethylene glycol 50 mass%) in which the polyvinyl alcohol and polyethylene glycol (mass average molecular weight: 20,000) were mixed at a solid content ratio of 1: 1 as a water-soluble resin was used. Produced the fin material 1A in the same manner as in Reference Example 2.

( Reference Example 4)
In Reference Example 4, a fin material 1 was produced in the same manner as Reference Example 1 except that a sodium salt of carboxymethyl cellulose was used as the water-soluble resin, and a water-soluble coating layer 5 having a thickness of 1 μm was formed.

(Example 5)
Example 5 uses a mixed resin (polyethylene glycol resin ratio of 90% by mass) in which the polyvinyl alcohol and polyethylene glycol (mass average molecular weight: 20,000) are mixed at a solid content ratio of 1: 9 as a water-soluble resin. The fin material 1 was produced in the same manner as in Reference Example 1 except that the water-soluble coating film layer 5 having a thickness of 0.2 μm was formed.

( Reference Example 6)
Reference Example 6 produced fin material 1 in the same manner as Reference Example 1 except that thiabendazole (solubility: 3 mg / 100 ml) was used as antibacterial agent 6 and water-soluble coating layer 5 having a film thickness of 1 μm was formed. did.

( Reference Example 7)
Reference Example 7 uses a mixed resin (resin ratio of polyethylene glycol 40% by mass) in which the polyvinyl alcohol and polyethylene glycol (mass average molecular weight: 150,000) are mixed at a solid content ratio of 6: 4 as a water-soluble resin. The fin material 1 was manufactured in the same manner as in Reference Example 1 except that the water-soluble coating film layer 5 having a thickness of 1 μm was formed.

( Reference Example 8)
In Reference Example 8, a fin material 1 was produced in the same manner as in Reference Example 1, except that an ammonium salt of carboxymethylcellulose was used as the water-soluble resin, and a water-soluble coating layer 5 having a thickness of 1 μm was formed.

Next, about 10 ml of pure water is sprayed on the fin materials 1 and 1A ( Reference Example 1, Reference Example 2, Example 3, Reference Example 4, Example 5, Reference Examples 6 to 8 ) assuming dew condensation water. Then, the extraction water containing the elution component from the coating layer that has flowed down is received by the plastic plate, the plate is tilted so that the extraction water flows down as it is, and the plastic plate is dried at room temperature in the following state. The antifungal antibacterial test shown in Fig. 1 was carried out. Moreover, about the fin materials 1 and 1A ( Reference example 1, Reference example 2, Example 3, Reference example 4, Example 5, Reference example 7, Reference example 8 ), the antibacterial agent 6 (zinc pyrithione) eluted to drain water In order to quantify the amount of elution, the fin materials 1 and 1A were immersed in running water for 24 hours. And intensity change of zinc derived from zinc pyrithione before and after immersion for 24 hours was measured by fluorescent X-ray measurement. These results are shown in Table 1.

  The fluorescent X-ray measurement was performed using a wavelength dispersion type fluorescent X-ray apparatus (LAB CENTER XRF-1800) manufactured by Shimadzu Corporation. A sample was prepared by cutting the fin materials 1 and 1A into a disk having a diameter of 5 cm. The strength of zinc is the strength obtained by subtracting the blank strength when zinc pyrithione is not added from the strength measured before immersion in running water to 100%, and the initial strength is obtained by subtracting the blank strength from the strength measured after immersion for 24 hours. Expressed as a ratio to strength. That is, the smaller the intensity, the more the zinc pyrithione is eluted.

(Anti-fungal antibacterial test)
According to the test by the glass ring method described in “Sadako Yamada et al .: Rapid antifungal activity test method on solid material surface, antibacterial fungus, Vol.31, No.11, 711-717 (2003)”. evaluated. The mold used was a mixture of three types of mold, black mold (Aspegillus niger), blue mold (Penicillium chrysogenum), and black mold (Cladosporium cladosporioides). The evaluation results are evaluated according to the 6 levels shown in Table 2, but 4 or more is effective, 6 is ◎ (excellent), 4 or 5 is ○ (good), and 3 or less is ineffective. Bad).

(Comparative Examples 1-3)
Comparative Examples 1 and 2, except for using those different antimicrobial agent 6 of the water-soluble coating layer 5 as in Reference Example 1 to produce a fin material 1 in the same manner as in Reference Example 1. Comparative Example 3 uses a mixed resin (resin ratio of polyethylene glycol 50 mass%) in which the polyvinyl alcohol and polyethylene glycol (mass average molecular weight: 20,000) are mixed at a solid content ratio of 1: 1 as a water-soluble resin, The fin material 1 was manufactured in the same manner as in Reference Example 1 except that the water-soluble coating layer 5 having a film thickness of 15 μm was formed. And it carried out similarly to the Example and the reference example, and implemented the antifungal property test of the fin material 1 (Comparative Examples 1-3). Moreover, about the fin material 1 (comparative example 3), it carried out similarly to the Example and the reference example, and measured the intensity | strength change of zinc derived from zinc pyrithione. These results are shown in Table 1.

From the results shown in Table 1, the fin materials of Reference Example 1, Reference Example 2, Example 3, Reference Example 4, Example 5, and Reference Examples 6 to 8 are antifungal antibacterials on plastic plates that have been brought into contact with the drained extracted water. As a result, it was confirmed that it was excellent. Incidentally, the third embodiment, the fin material of Example 5, water-soluble coating layer, since it is composed of a polyvinyl alcohol which contains a predetermined amount of predetermined polyethylene glycol, was particularly excellent. It was confirmed that the fin materials of Comparative Examples 1 and 2 were inferior in antibacterial and antifungal properties because the antibacterial agents contained in the water-soluble coating layer did not satisfy the claims. Furthermore, it was confirmed that the fin material of Comparative Example 3 was inferior in antifungal property because the film thickness of the water-soluble coating layer did not satisfy the scope of the claims.

(A) is sectional drawing which shows typically the cross section of the aluminum fin material for heat exchangers which concerns on this invention, (b) is sectional drawing of another aluminum fin material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Fin material 2 Substrate 3 Ground treatment layer 4 Hydrophilic coating layer 5 Water-soluble coating layer 6, 7 Antibacterial agent

Claims (2)

A substrate made of aluminum or an aluminum alloy;
A base treatment layer made of an inorganic oxide or an organic-inorganic composite compound formed on the substrate;
1-100 parts by mass of a water-soluble resin having a hydroxyl group in the molecule with respect to 100 parts by mass of polyacrylic acid or polyacrylate with a film thickness of 0.1-10 μm formed on the base treatment layer A hydrophilic coating layer made of a hydrophilic resin,
A water-soluble coating layer formed of a water-soluble resin having a film thickness of 0.1 to 10 μm on the hydrophilic coating layer and having a hydroxyl group in the molecule,
The water-soluble coating layer contains zinc pyrithione as antibacterial agents, said heat exchanger aluminum fin material when immersed for 24 hours in running water at 20 ° C., with the zinc pyrithione is eluted 50%
The water-soluble coating layer contains polyethylene glycol having a mass average molecular weight of less than 100,000, and the content of the polyethylene glycol is 50% by mass or more as a ratio of the resin component excluding zinc pyrithione of the water-soluble coating layer. An aluminum fin material for a heat exchanger, characterized in that there is.   The aluminum fin material for a heat exchanger according to claim 1, wherein the hydrophilic coating layer contains an antibacterial agent having a solubility in pure water at 20 ° C of 1 mg / 100 ml or less.

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