Aluminum fin material

Abstract

To provide an aluminum-made fin material capable of improving appearance by blackening a surface, having excellent hydrophilicity, and capable of suppressing adhesion of dew condensation water SOLUTION: The aluminum-made fin material 10 has an aluminum sheet 1 and a film layer 2 formed on the surface of the aluminum sheet 1. The coating layer 2 has a corrosion-resistant resin coating layer 3 and a hydrophilic coating layer 4 in this order from the aluminum sheet 1 side. The corrosion-resistant resin coating layer 3 contains a black pigment 6 and a dispersion aid, the black pigment 6 is at least one selected from carbon black, a metal inorganic compound-based pigment, and an organic pigment, a mass ratio of the black pigment 6 to a total mass of the corrosion-resistant resin coating layer 3 is 35 mass% or less, a mass ratio of the dispersion aid to a mass of the black pigment 6 in the corrosion-resistant resin coating layer 3 is 10 mass% or more, and an L * value in an L * a * b color system measured on the surface of the aluminum-made fin material 10 by a spectrophotometer is 83 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aluminum fin material, and more particularly to an aluminum fin material suitable for use in a heat exchanger for an outdoor unit of an air conditioner or the like. [Background technology]

[0002] Heat exchangers are used in a variety of products, including air conditioners such as room air conditioners and packaged air conditioners, refrigerated showcases, refrigerators, oil coolers, radiators, etc. Among these heat exchangers, in recent years, research has been conducted into the design of outdoor units for air conditioners with the aim of improving their aesthetic appearance.

[0003] For example, Patent Document 1 proposes a grill mounting structure for an outdoor unit for an air conditioner that can prevent a loss of design due to the mounting of an outlet grill. The outdoor unit for an air conditioner described in Patent Document 1 has a contrasting color tone between the light-colored outlet grill and the dark-colored internal structure, for example, so that the conspicuous mounting part is hidden and less visible from the outside.

[0004] Additionally, to improve design, fins that have been colored by adding pigments or dyes to the coating are becoming popular, such as blue fins that give a clean impression and gold fins that give a luxurious impression.

[0005] In recent years, the popularity of ATW (Air To Water), a heat pump type heating appliance, has increased in Europe, and as a result, demand for outdoor units equipped with heat exchangers using aluminum fins has also increased. However, people living in Europe tend to view outdoor units as interior décor, and many find the movement of the fan when it is in operation to be unpleasant. As a result, there is a growing demand for outdoor units with black exterior frames, built-in fans, and even the fins located behind the fans.

[0006] When the surface temperature of a heat exchanger's fin material drops below the dew point, condensation water adheres to it. If the fin material's surface is not hydrophilic, the contact angle of the condensation water increases, causing it to splash around in the living environment, a phenomenon known as water splashing. Furthermore, when multiple condensation water droplets on the surface combine and grow, they form bridges between adjacent fin materials, blocking the ventilation passages between the fin materials and increasing ventilation resistance. Therefore, heat exchanger fin materials are required to have the ability to suppress the adhesion of condensation water. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-136005 Summary of the Invention [Problem to be solved by the invention]

[0008] Conventional black fins are all after-coated by electrodeposition coating after the heat exchanger is manufactured, but due to the principle of electrodeposition coating, it is difficult to apply multiple coatings to an aluminum substrate. Therefore, in fins colored black by electrodeposition coating, the coating film is single-layered, which makes it difficult to achieve various coating properties.

[0009] The present invention has been made in consideration of such problems, and aims to provide an aluminum fin material that can have a blackened surface to improve aesthetics, has excellent hydrophilicity, and can suppress the adhesion of condensation water. [Means for solving the problem]

[0010] The above object of the present invention is achieved by the following configuration [1] relating to an aluminum fin material.

[0011] [1] An aluminum fin material having an aluminum plate and a coating layer formed on the surface of the aluminum plate, The coating layer has, in order from the aluminum plate side, a corrosion-resistant resin coating layer and a hydrophilic coating layer, the corrosion-resistant resin coating layer contains a black pigment, L measured on the aluminum fin surface using a spectrophotometer * a * Lightness L in the b color system * An aluminum fin material characterized in that the value is 83 or less.

[0012] Furthermore, preferred embodiments of the present invention relating to the aluminum fin material relate to the following [2] to [8].

[0013] [2] The aluminum fin material according to [1], characterized in that the black pigment is at least one selected from carbon black, inorganic metal compound pigments, and organic pigments.

[0014] [3] The aluminum fin material described in [1], characterized in that the black pigment is carbon black and the mass ratio of the carbon black to the total mass of the corrosion-resistant resin coating layer is 35 mass% or less.

[0015] [4] The black pigment is carbon black, and the content of the carbon black per unit area of ​​the corrosion-resistant resin coating layer is 0.1 (mg / dm 2 The aluminum fin material according to [1], characterized in that it is at least 100%.

[0016] [5] The aluminum fin material according to any one of [1] to [4], characterized in that the corrosion-resistant resin film layer contains at least one selected from epoxy resin, urethane resin, and acrylic resin to which a Zr-based crosslinking agent has been added.

[0017] [6] The aluminum fin material according to any one of [1] to [4], wherein the corrosion-resistant resin coating layer contains a dispersion aid.

[0018] [7] The aluminum fin material according to any one of [1] to [4], characterized in that the hydrophilic coating layer contains both an acrylic resin and a polyether-based polyurethane resin.

[0019] [8] The aluminum fin material according to any one of [1] to [4], characterized in that a base treatment layer is provided between the aluminum plate and the coating layer. [Effects of the Invention]

[0020] According to the present invention, a corrosion-resistant resin film layer and a hydrophilic film layer are provided, and the corrosion-resistant resin film layer contains a black pigment. * Since the values ​​are controlled within a predetermined range, it is possible to provide an aluminum fin material that has excellent aesthetics and hydrophilicity and can prevent a decrease in heat exchange efficiency. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an aluminum fin material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] As a result of intensive research to solve the above problems, the present inventors have found that in a fin material having, in order from the aluminum plate side, a corrosion-resistant resin film layer and a hydrophilic film layer, it is effective to incorporate a black pigment into the corrosion-resistant resin film layer. That is, by coloring the corrosion-resistant resin film layer and then forming a hydrophilic film layer on top of it, a fin material that satisfies both aesthetics and hydrophilicity can be obtained. The present invention was made based on the above findings.

[0023] Hereinafter, an embodiment of the aluminum fin material according to the present invention will be described in detail. In this specification, aluminum or an aluminum alloy may be simply referred to as aluminum. In addition, in the present invention, the L * a * Lightness L in the b color system * However, in the present specification, this value is simply referred to as L * There is something called value.

[0024] [Aluminum fin material] FIG. 1 is a schematic cross-sectional view showing an aluminum fin material according to an embodiment of the present invention. As shown in FIG. 1, an aluminum fin material 10 according to this embodiment (hereinafter, sometimes simply referred to as "fin material 10") has an aluminum plate 1, a coating layer 2 formed on the surface of the aluminum plate 1, and a base treatment layer 5 formed between the aluminum plate 1 and the coating layer 2. The coating layer 2 has, in order from the aluminum plate 1 side, a corrosion-resistant resin coating layer 3 and a hydrophilic coating layer 4. The corrosion-resistant resin coating layer 3 contains a black pigment 6, which causes the fin material 10 to be colored black. Furthermore, in this embodiment, the L on the surface of the fin material 10 * In this embodiment, an example is shown in which the undercoat treatment layer 5 is formed, but the undercoat treatment layer 5 is not necessarily required, and the presence or absence of the layer can be selected as needed.

[0025] In the fin material 10 according to this embodiment, the corrosion-resistant resin film layer 3 contains a black pigment 6, and the L * Since the value is specified to be 83 or less, it is possible to obtain a fin material 10 with the desired black color. Furthermore, since the hydrophilic coating layer 4 having hydrophilic properties is laminated on the corrosion-resistant resin coating layer 3, it is possible to prevent condensed water from adhering to the surface of the fin material 10. As a result, it is possible to prevent water from splashing and the formation of bridges between adjacent fin materials, and it is possible to suppress a decrease in heat exchange efficiency.

[0026] Hereinafter, the L of the surface of the fin material 10 according to this embodiment will be * The values ​​and components of the fin material 10 will be specifically described.

[0027] [L * Value: 83 or less) L * The value is an index representing brightness, and the closer to 0, the blacker it is, and the closer to 100, the whiter it is. In this embodiment, in order to satisfy specific requirements regarding the color of the fin material 10, the L * The value is specified. * If the value exceeds 83, the desired black color cannot be obtained, and the aesthetic appearance is deteriorated. * The value is 83 or less, preferably 80 or less, more preferably 70 or less, even more preferably 60 or less, even more preferably 50 or less, even more preferably 40 or less, and especially preferably 30 or less. On the other hand, the L on the surface of the fin material 10 * Although there is no particular limit to the lower limit of the value, the darker the black, the more preferable it is. * Specifically, the L * The value is particularly preferably 0, but may be 0.1 or more, or may be 0.5 or more. In addition, from the viewpoint of widening the latitude in selecting the type and content of the black pigment, L * The value may be 1 or more, 3 or more, and preferably 5 or more.

[0028] L * The value varies depending on various factors such as the type of black pigment, particle size and content, and the presence or absence and content of a dispersing agent. Therefore, by appropriately adjusting the above factors, it is possible to achieve a L * The value can be controlled to a desired range.

[0029] In addition, L *The values ​​can be measured using a spectrophotometer, such as a spectrophotometer (CM-600d) manufactured by Konica Minolta Japan Inc. or a multi-angle spectrophotometer (MA-68II) manufactured by X-Rite Inc.

[0030] [Aluminum plate] The aluminum plate 1 represents a plate made of aluminum or an aluminum alloy. As the aluminum plate 1, an aluminum plate generally used for aluminum fin materials can be used. As the aluminum plate 1, it is preferable to use 1000 series aluminum specified in JIS H 4000:2014 because it has excellent thermal conductivity and processability. More specifically, it is more preferable to use aluminum of alloy numbers 1050, 1070, and 1200 as the aluminum plate. However, the aluminum plate 1 of the aluminum fin material 10 according to this embodiment is not limited to the above.

[0031] The thickness of the aluminum plate 1 can be designed appropriately depending on the specifications of the fin material 10. In the fin material 10 for a heat exchanger, from the viewpoint of the strength of the fin, the thickness is preferably 0.08 mm or more, and more preferably 0.1 mm or more. On the other hand, from the viewpoint of the workability into fins, the heat exchange efficiency, etc., the thickness of the fin material 10 is preferably 0.3 mm or less, and more preferably 0.2 mm or less.

[0032] [Coating layer] <Corrosion-resistant resin coating layer> The corrosion-resistant resin film layer 3 is formed on the aluminum plate 1 mainly to enhance the corrosion resistance of the aluminum plate 1, and preferably contains a hydrophobic resin. When a base treatment layer 5 is formed on the surface of the aluminum plate 1, the corrosion-resistant resin film layer 3 is formed on the base treatment layer 5. The corrosion-resistant resin film layer 3 can be formed, for example, by applying a coating composition containing a hydrophobic resin and a black pigment 6 onto the aluminum plate 1 or the base treatment layer 5, followed by drying and baking.

[0033] In this embodiment, the corrosion-resistant resin coating layer 3 is formed on the surface of the aluminum plate 1 directly or via a base treatment layer 5 or the like, which makes it difficult for moisture such as condensation water, oxygen, ions such as chloride ions, and the like to penetrate into the aluminum plate 1. As a result, corrosion of the aluminum plate 1 and the generation of aluminum oxides that cause odors can be suppressed.

[0034] The hydrophobic resin in the corrosion-resistant resin film layer may be any known hydrophobic resin, such as epoxy resin, urethane resin, acrylic resin with a Zr-based crosslinking agent added, phenol resin, amine resin, polyester resin, silicone resin, or fluororesin.

[0035] (black pigment) The corrosion-resistant resin film layer 3 contains a black pigment 6. In this embodiment, the surface of the fin material 10 is blackened to improve the appearance. * The black pigment to be used is not particularly limited as long as the value can be controlled within the above range, and various black pigments can be used. Specifically, at least one selected from carbon black containing C (carbon) as the main component, inorganic metal compound pigments not containing C, and organic pigments containing C, H, and N as the main components can be used.

[0036] Examples of carbon black include furnace black, channel black, acetylene black, thermal black, graphitized black, and Ketjen black. Examples of inorganic metal compound pigments include chromium oxide, iron oxide, titanium black, and composite oxides. Examples of organic pigments include aniline black. Of these pigments, it is preferable to use carbon black.

[0037] Average particle size of black pigment The average particle size of the black pigment 6 is not particularly limited. However, if the black pigment 6 has a small average particle size and is uniformly dispersed in the corrosion-resistant resin film layer 3, L * Specifically, the average particle size of the black pigment 6 in the corrosion-resistant resin film layer 3 is preferably 10 nm or more. On the other hand, if the average particle size of the black pigment 6 in the corrosion-resistant resin film layer 3 becomes too large, the L * In addition, if the average particle size of the black pigment 6 is larger than the thickness of the corrosion-resistant resin coating layer 3, it may affect the hydrophilicity of the hydrophilic coating layer 4. Therefore, the average particle size of the black pigment 6 in the corrosion-resistant resin coating layer 3 is preferably smaller than the thickness of the corrosion-resistant resin coating layer 3, for example, preferably 1000 nm or less, and more preferably 100 nm or less.

[0038] When carbon black is used as the black pigment 6, the average particle size of the carbon black as a raw material before being mixed into the coating composition will be larger after forming the corrosion-resistant resin coating layer 3. Therefore, the average particle size of the carbon black as a raw material for the coating composition for the corrosion-resistant resin coating layer 3 is preferably 10 nm or more and 500 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less.

[0039] Black pigment content In this embodiment, the L of the surface of the fin material 10 *The content of the black pigment is not particularly limited as long as the value can be controlled within the above-mentioned range. From the viewpoint of obtaining a desired black color without reducing corrosion resistance, the mass ratio of carbon black to the total mass of the corrosion-resistant resin coating layer 3 is preferably 35 mass% or less, more preferably 15 mass% or less, and even more preferably 3 mass% or less.

[0040] On the other hand, the L on the surface of the fin material 10 * As long as the value can be controlled within the above range, there is no particular lower limit to the mass ratio of the black pigment. From the viewpoint of easily obtaining a desired black color, the content of carbon black per unit area of ​​the corrosion-resistant resin coating layer 3 is 0.1 (mg / dm 2 ) or more, and 0.3 (mg / dm 2 ) or more, and 1 (mg / dm 2 ) or more is more preferable.

[0041] (Dispersion aid) The corrosion-resistant resin coating layer 3 preferably contains a dispersing aid (not shown) in addition to the black pigment 6. The dispersing aid may be any that can easily mix the hydrophobic black pigment 6 with the surrounding water and disperse the black pigment 6 more uniformly in the corrosion-resistant resin coating layer 3, and in addition to general dispersing agents, surfactants and the like can also be used. Specific examples of the dispersing aid include acrylic dispersing agents, polyester dispersing agents, and polyamine dispersing agents.

[0042] Dispersing agent content In this embodiment, if the compatibility between the black pigment 6 and the hydrophobic resin is good, a dispersing aid is not necessarily required. For example, when carbon black is used as the black pigment 6 and an acrylic dispersing agent is used as the dispersing aid, even better dispersibility can be achieved if the mass ratio of the dispersing aid to the mass of carbon black in the corrosion-resistant resin coating layer 3 is 10 mass% or more. As a result, it is possible to prevent agglomerated carbon black from becoming a starting point for corrosion, and the occurrence of corrosion can be suppressed even in more severe environments. Therefore, the mass ratio of the dispersing aid to the mass of carbon black is preferably 10 mass% or more, and more preferably 20 mass% or more.

[0043] On the other hand, if the mass ratio of the dispersing aid is increased too much, the effect of dispersing the carbon black will reach saturation and the content of the hydrophobic resin in the corrosion-resistant resin coating layer 3 will decrease, making it difficult to obtain the desired corrosion resistance. Therefore, the mass ratio of the dispersing aid to the mass of carbon black is preferably 30 mass% or less.

[0044] The mass ratio of the dispersing aid to the carbon black in the corrosion-resistant resin coating layer 3 can be considered to be the same as the mass ratio of the dispersing aid to the carbon black in the coating composition. Therefore, in order to set the mass ratio of the dispersing aid in the corrosion-resistant resin coating layer 3 within the above range, the amount of dispersing aid added may be adjusted when preparing the coating composition so that the desired mass ratio is achieved relative to the mass of carbon black.

[0045] (Other ingredients) As long as the effects of the present invention are not impaired, other optional components may be contained in the corrosion-resistant resin coating layer 3. Examples of optional components include various water-based solvents and paint additives for improving coatability, workability, and physical properties of the coating. Examples of paint additives include water-soluble organic solvents, crosslinking agents, surfactants, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, anti-foaming agents, rust inhibitors, antibacterial agents, anti-fungal agents, etc. One type of these paint additives may be contained, or two or more types may be contained.

[0046] The amount of the corrosion-resistant resin film layer 3 is not particularly limited, but from the viewpoint of imparting sufficient corrosion resistance to the aluminum plate, it is preferred that the amount be 0.5 mg / dm 2 It is preferable that the concentration is 2.0 mg / dm or more. 2 On the other hand, from the viewpoint of suppressing a decrease in the heat exchange efficiency of the fin, the coating amount of the corrosion-resistant resin coating layer 3 is set to 150 mg / dm 2 It is preferable to keep it below 50 mg / dm 2 It is more preferable to set the following:

[0047] The thickness of the corrosion-resistant resin film layer 3 is preferably 0.05 μm or more from the viewpoint of obtaining good corrosion resistance, and is preferably 15 μm or less from the viewpoints of good film-forming properties, reducing defects such as cracks, and keeping the heat transfer resistance of the corrosion-resistant resin film layer low, thereby obtaining good heat exchange efficiency of the fin. The thickness of the corrosion-resistant resin film layer 3 and the amount of hydrophobic resin applied can be adjusted by the concentration of the coating composition used to form the corrosion-resistant resin film layer 3 and the selection of the bar coater number.

[0048] The corrosion-resistant resin film layer 3 may consist of one layer or two or more layers. When the corrosion-resistant resin film layer 3 consists of multiple layers, the black pigment 6 may be contained in any one of the layers, or in multiple layers.

[0049] <Hydrophilic film layer> The hydrophilic coating layer 4 is a coating layer formed to improve the hydrophilicity of the surface of the fin material 10, prevent condensation water from adhering to the surface of the fin material 10, and suppress a decrease in heat exchange efficiency, and preferably contains a hydrophilic resin. The hydrophilic resin may contain one type of resin or two or more types of resins as long as it has a hydrophilic group. Examples of the hydrophilic group include a hydroxyl group, a carboxyl group, a sulfonic acid group, and a polyether group.

[0050] Examples of those having a hydroxyl group include polyethylene glycol (PEG) and polyvinyl alcohol (PVA). Examples of those having a carboxyl group include polyacrylic acid (PAA). Examples of those having a hydroxyl group and a carboxyl group include carboxymethyl cellulose (CMC). Examples of those having a sulfonic acid group include sulfoethyl acrylate. Examples of those having a polyether group include polyethylene glycol (PEG) and modified compounds thereof.

[0051] Even when other functional coating layers are formed on the surface of the hydrophilic coating layer 4, it is preferable to select a hydrophilic resin that more suitably exhibits the desired hydrophilicity. Specifically, it is preferable to use a hydrophilic resin containing a sulfonic acid group or a hydrophilic resin containing a polyether group, i.e., an ether bond, and it is more preferable to use a hydrophilic resin containing a sulfonic acid group and an ether bond, and it is particularly preferable to use an acrylic resin containing a sulfonic acid group and an ether bond.

[0052] The acrylic resin containing a sulfonic acid group and an ether bond is an acrylic resin containing an unsaturated double bond group and a sulfonic acid group, and examples thereof include polyvinyl ether-sulfonic acid acrylic copolymer, benzyl ether-sulfonic acid acrylic copolymer, etc. However, the acrylic resin containing a sulfonic acid group and an ether bond is not limited to these.

[0053] In this embodiment, particularly from the viewpoint of improving the processability of the hydrophilic coating layer, it is preferable that the hydrophilic coating layer contains both an acrylic resin and a polyether-based resin having slip properties, and it is more preferable that the hydrophilic coating layer contains both an acrylic resin and a polyether-based polyurethane resin having extensibility in addition to slip properties.

[0054] In addition to the above, the hydrophilic resin may also be a copolymer of two or more types of monomers having a hydrophilic group. For example, a copolymer of acrylic acid and sulfoethyl acrylate may be used. The copolymer 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.

[0055] To enhance the hydrophilicity of the hydrophilic coating layer 4, a surfactant may be contained. Any of anionic, cationic, and nonionic surfactants can be used, but nonionic surfactants are preferred from the viewpoint of ease of dispersion in the hydrophilic coating layer.

[0056] Examples of nonionic surfactants include ethylenediamine polyoxypropylene-polyoxyethylene condensates, polyoxyethylene sorbitan monolaurate, polyoxyethylene polyoxypropylene block polymers, and polyoxyethylene sorbitan monostearate.

[0057] The hydrophilic coating layer 4 can be formed by applying a coating composition containing a hydrophilic resin onto the corrosion-resistant resin coating layer 3, followed by drying and solidifying by baking or the like.

[0058] The amount of the hydrophilic coating layer 4 is 0.1 mg / dm 2 It is preferable to set the concentration to 0.5 mg / dm or more. 2 More preferably, it is 1 mg / dm or more. 2 Furthermore, from the viewpoint of preventing the hydrophilic resin from eluting when the surface of the fin material is wetted with water and affecting other coating layers, the coating amount of the hydrophilic coating layer 4 is set to 50 mg / dm 2 It is preferable to keep it below 30 mg / dm 2 It is more preferable to keep it below 10 mg / dm 2 It is more preferable that:

[0059] The hydrophilic coating layer 4 may contain the above-mentioned black pigment as long as the hydrophilicity is not reduced. However, even if the hydrophilic coating layer 4 contains the black pigment, when the surface of the fin material is wetted with water, the black pigment flows out together with the water-soluble components in the hydrophilic coating layer 4, and the intensity of the black color decreases over time. In contrast, the fin material according to this embodiment has a black pigment contained in the corrosion-resistant resin coating layer, so that the L * Since the value is controlled, the hydrophilic coating layer 4 does not need to contain a black pigment, and it is more preferable that the hydrophilic coating layer 4 does not contain a black pigment.

[0060] In addition to the hydrophilic resin and surfactant, other optional components may be contained in the hydrophilic coating layer 4, provided that the effects of the present invention are not impaired. Examples of optional components include various water-based solvents and paint additives for improving the coatability, workability, and physical properties of the coating layer. Examples of paint additives include water-soluble organic solvents, crosslinking agents, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, anti-foaming agents, rust inhibitors, antibacterial agents, anti-fungal agents, etc. These paint additives may be contained alone or in combination of two or more.

[0061] The thickness of the hydrophilic coating layer is not particularly limited, but the density of the hydrophilic coating layer is preferably 1 g / cm 3 Assuming this, in order to obtain good hydrophilicity, the thickness is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more. There is no particular upper limit, but it is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. The thickness of the hydrophilic coating layer can be adjusted by the concentration of the coating composition used to form the hydrophilic coating layer, the selection of the bar coater number, and the like.

[0062] The total thickness of the coating layer 2 of the fin material 10 is preferably 5 μm or less from the viewpoint of suppressing a decrease in the heat exchange efficiency of the fin material 10. In this embodiment, the coating layer 2 refers to the corrosion-resistant resin coating layer 3 and the hydrophilic coating layer 4.

[0063] <Undercoat treatment layer> In this embodiment, a base treatment layer 5 may be provided between the aluminum plate 1 and the coating layer 2. By providing the base treatment layer 5 in the fin material 10, the adhesion between the aluminum plate 1 and the corrosion-resistant resin coating layer 3 can be increased, and the corrosion resistance of the aluminum plate 1 can be further improved.

[0064] Any conventionally known material can be used for the base treatment layer 5 as long as it has the effect of increasing the adhesion between the aluminum plate 1 and the corrosion-resistant resin coating layer 3. For example, a layer made of an inorganic oxide or an inorganic-organic composite compound can be used as the base treatment layer 5. The inorganic material constituting the inorganic oxide or inorganic-organic composite compound preferably has chromium (Cr), zirconium (Zr) or titanium (Ti) as the main component.

[0065] The layer made of an inorganic oxide that will become the undercoat treatment layer 5 can be formed, for example, by subjecting the aluminum plate 1 to a chromate phosphate treatment, a zirconium phosphate treatment, a zirconium oxide treatment, a chromate chromate phosphate treatment, a zinc phosphate treatment, a titanic acid phosphate treatment, or the like. However, the type of inorganic oxide is not limited to those formed by these treatments.

[0066] The layer made of an inorganic-organic composite compound that serves as the undercoat treatment layer 5 can be formed, for example, by subjecting the aluminum plate 1 to a coating type chromate treatment or a coating type zirconium treatment. Specific examples of such inorganic-organic composite compounds include an acrylic-zirconium composite.

[0067] The thickness of the undercoat treatment layer 5 is not particularly limited and may be set appropriately, but the amount of adhesion per unit area is preferably 1 to 100 mg / m in terms of metal (Cr, Zr, Ti). 2The deposition amount and film thickness of the base treatment layer 5 can be adjusted by adjusting the concentration of the chemical conversion treatment solution used to form the base treatment layer and the film formation treatment time.

[0068] Before forming the primer treatment layer 5, the surface of the aluminum plate 1 may be degreased in advance using an alkaline degreasing solution, which improves the reactivity of the primer treatment and also improves the adhesion of the formed primer treatment layer.

[0069] <Functional coating layer> In this embodiment, the coating layer 2 may further include a functional coating layer (not shown). For example, when forming a functional coating layer for the purpose of suppressing adhesion of contaminants, the functional coating layer may be formed on the outermost surface of the fin material 10. Such a functional coating layer preferably contains a silicone component which has low surface free energy and is thought to have low adhesive properties to substances, thereby reducing adhesion of contaminants, mainly oily components.

[0070] It is also preferable that the functional coating layer formed on the outermost surface of the fin material 10 further contains a resin that enhances lubricity, in order to increase the lubricity of the surface of the fin material 10. Forming a functional coating layer that enhances lubricity reduces the coefficient of friction on the surface of the fin material 10, improving press formability when processing the fin material 10 into a fin. Such a functional coating layer can be formed, for example, by applying a paint containing a silicone component and, if necessary, a resin that enhances lubricity, onto the hydrophilic coating layer and then solidifying it by drying or the like.

[0071] The silicone component is a polymer of a silicon compound, and is a compound having a siloxane bond as a skeleton. The silicone component preferably contains a modified polydimethylsiloxane derivative having one or more functional groups selected from polyether groups, epoxy groups, methacrylic groups, amino groups, phenyl groups, hydrogen groups, and hydroxyl groups in its structure, because it has particularly high dispersibility in paints and high fixability in resin films, and more preferably contains a modified polydimethylsiloxane derivative having one or more functional groups selected from the group consisting of epoxy groups, methacrylic groups, phenyl groups, and hydrogen groups in its structure. Silicones containing long-chain alkyl groups are also preferred. Such modified polydimethylsiloxane derivatives and silicones containing long-chain alkyl groups can be nonionic, anionic, or cationic.

[0072] The amount of silicone component attached in the functional coating layer is 0.0010 g / m from the viewpoint of obtaining sufficient oil repellency and suppressing the attachment of oily components. 2 It is preferable that the density is 0.006 g / m or more. 2 More preferably, it is 0.01 g / m or more. 2 On the other hand, since the silicone component is oil-repellent and hydrophobic at the same time, the amount of silicone component attached is preferably 1.0 g / m or more from the viewpoint of preventing the hydrophilic function of the hydrophilic coating layer 4 from being impaired. 2 It is preferable that the concentration is 0.3 g / m or less. 2 It is more preferable that the concentration is 0.1 g / m or less. 2 It is more preferable that the concentration is 0.05 g / m or less. 2 It is particularly preferred that:

[0073] When imparting lubricity to the functional coating layer, examples of resins that enhance lubricity include resins having hydrophilic groups. The resin may contain one type or two or more types. The hydrophilic groups are as described for the hydrophilic coating layer 4. As the resin that enhances lubricity to be contained in the functional coating layer, it is preferable to use a resin having a hydroxyl group, and it is more preferable to use polyethylene glycol (PEG, PEO).

[0074] In addition to the above, the functional coating layer may contain other optional components within the scope of the present invention, such as various water-based solvents and paint additives for improving coatability, workability, and physical properties of the coating. Examples of paint additives include water-soluble organic solvents, crosslinking agents, surfactants, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, anti-foaming agents, rust inhibitors, antibacterial agents, anti-fungal agents, etc. One type of these paint additives may be contained, or two or more types may be contained.

[0075] The amount of resin attached to the functional coating layer is 0.01 g / m to ensure sufficient lubricity. 2 It is preferable that the concentration is 0.03 g / m or more. 2 More preferably, it is 0.05 g / m or more. 2 On the other hand, from the viewpoint of preventing a decrease in the workability of applying the functional coating layer, the coating amount is set to 5 g / m or more. 2 It is preferable that the density is 0.5 g / m or less. 2 More preferably, it is 0.3 g / m or less. 2 It is more preferable that the concentration is 0.1 g / m or less. 2 Even more preferably, the following is true:

[0076] The thickness of the functional coating layer is not particularly limited, but the density of the functional coating layer is preferably 1 g / cm 3 Assuming this, in order to obtain good oil repellency, the thickness is preferably 0.001 μm or more, more preferably 0.01 μm or more, and even more preferably 0.03 μm or more. In addition, in order to obtain good coating workability during film formation, the thickness is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less. The thickness of the functional coating layer can be adjusted by the concentration of the coating composition used to form the functional coating layer, the selection of the bar coater number used to form the layer, and the like.

[0077] The coating layer 2 may be formed on at least one surface of the aluminum plate 1, but may also be formed on both surfaces of the aluminum plate 1. Furthermore, when the coating layer 2 is formed on both surfaces of the aluminum plate 1, the coating layers do not need to be in the same form. [Example]

[0078] The present invention will be explained in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples, and modifications can be made within the scope of the invention, and all such modifications are included in the technical scope of the present invention.

[0079] [Manufacturing of aluminum fin materials] First, an aluminum plate having a thickness of 0.095 mm and alloy number 1070 specified in JIS H 4000:2014 was used, and a phosphate chromate treatment was performed on the surface of the aluminum plate to form a primer layer. Next, a coating composition containing a hydrophobic resin and carbon black was applied with a bar coater and baked at 250°C to form a corrosion-resistant resin film layer. Recoating was carried out as necessary, and the coating amount of the corrosion-resistant resin film layer was adjusted to 0.5 to 800 mg / dm 2 The coating weight of the corrosion-resistant resin coating layer was calculated from the mass ratio of the black pigment to the corrosion-resistant resin coating layer and the content of the black pigment. Thereafter, a coating composition containing an acrylic resin and a polyether-based polyurethane resin was applied to the surface of the corrosion-resistant resin film layer using a bar coater, and then baked at 150°C to form a hydrophilic film layer, thereby producing an aluminum fin material. The coating amount of the hydrophilic film layer was 2.0 mg / dm 2 It was decided. In forming the corrosion-resistant resin film layer, carbon black was used as the black pigment, epoxy resin, urethane resin or acrylic resin was used as the resin material, and a dispersant was used as the dispersing aid.

[0080] [Measurement of color tone of aluminum fin material] The L of the obtained aluminum fin material * The L value was measured using a spectrophotometer (CM-600d, manufactured by Konica Minolta Japan, Inc.) by the specular component exclude (SCE) method. * The values ​​were measured without pretreatment and after immersion in running water. The immersion conditions were room temperature for 120 hours. The evaluation criteria for aesthetics were L * A value of 83 or less was considered good, and a value of 80 or less was considered excellent.

[0081] [Evaluation of aluminum fin materials] <Evaluation of hydrophilicity> At room temperature, approximately 1 μL of pure water was dropped onto the surface of the aluminum fin material, and the contact angle of the droplet (pure water) was measured using a contact angle meter (Kyowa Interface Science Co., Ltd., CA-05 model). The smaller the contact angle, the better the hydrophilicity. As a criterion for evaluating hydrophilicity, a contact angle of 40° or less was considered good.

[0082] <Corrosion resistance evaluation> (Moisture resistance test) The aluminum fin material was placed in an environment with a temperature of 49°C and a humidity of 98%, and after 100 hours, the corrosion condition was evaluated using RN (rating number). The higher the RN value, the better the moisture resistance. As a moisture resistance evaluation standard, an RN of 8.0 or higher was considered good.

[0083] (Salt Spray Testing (SST)) The aluminum fin material was subjected to an even more severe corrosive environment to evaluate its corrosion resistance. Specifically, the aluminum fin material was subjected to a salt spray test for 100 hours based on the salt spray test method specified in JIS Z 2371:2015, and then the corrosion condition was visually observed to confirm whether or not corrosion had occurred.

[0084] In this example, a specimen that showed good results in the moisture resistance test was judged to have good corrosion resistance, and a specimen that showed no corrosion in the SST test, which reproduced a severe corrosive environment, was judged to have excellent corrosion resistance.

[0085] Materials used in the corrosion-resistant resin film layer and hydrophilic film layer and their content, L * The values ​​are shown in Tables 1 and 2 below, and the evaluation results are shown in Table 3 below. In Tables 1 and 2 below, the corrosion-resistant layer refers to the corrosion-resistant resin film layer, and the hydrophilic layer refers to the hydrophilic film layer. The mass ratio of the black pigment to the corrosion-resistant layer or hydrophilic layer is the value obtained by dividing the mass of carbon black contained in the corrosion-resistant layer or hydrophilic layer by the mass of the corrosion-resistant layer or hydrophilic layer containing the carbon black, and is expressed in mass %. The content of the black pigment to the corrosion-resistant layer or hydrophilic layer is the mass of carbon black per unit area of ​​the corrosion-resistant layer or hydrophilic layer, and is expressed in mg / dm 2 The mass ratio of the dispersing aid to the black pigment is the value obtained by dividing the mass of the dispersing aid contained in the corrosion-resistant layer or the hydrophilic layer by the mass of the carbon black in the corrosion-resistant layer or the hydrophilic layer containing the dispersing aid, and is expressed in mass %.

[0086] [Table 1]

[0087] [Table 2]

[0088] [Table 3]

[0089] As shown in Tables 1 to 3 above, inventive examples Nos. 1 to 25, the corrosion-resistant resin film layer contains a black pigment, and L *Since the values ​​were within the specified range, a fin material with excellent aesthetics was obtained. Furthermore, by providing a hydrophilic resin film layer on top of the corrosion-resistant resin film layer, the contact angle was 40° or less, which provided excellent hydrophilicity without impairing aesthetics, and a fin material was obtained that can prevent a decrease in heat exchange efficiency. Three types of resin were used as materials for the corrosion-resistant resin film layer: epoxy resin, urethane resin, and acrylic resin with a Zr-based crosslinking agent added, and similar results were obtained regardless of the resin used.

[0090] In addition, Examples 1 to 25 had an RN of 8.0 or more, which evaluates moisture resistance, and thus exhibited excellent corrosion resistance. Furthermore, among the above-mentioned examples, Examples 1 to 12, 17 to 18, 20 to 21, and 23 had the mass ratio of the black pigment to the corrosion-resistant resin film layer and the mass ratio of the dispersing aid to the black pigment all within the preferred ranges specified in the present invention. Therefore, no corrosion occurred even in the SST test, which is a more severe corrosion test, and excellent corrosion resistance was obtained.

[0091] On the other hand, Comparative Example No. 1 is a fin material formed with a corrosion-resistant resin film layer containing a black pigment, but since no hydrophilic film layer is formed, the contact angle increases and the desired hydrophilicity cannot be obtained. Also, Comparative Example No. 2 is a fin material formed with a corrosion-resistant resin film layer and a hydrophilic film layer, but the hydrophilic film layer contains a black pigment, and the L after immersion in running water * The values ​​exceeded the upper limit specified in the present invention. This is thought to be because the carbon black was washed out of the coating together with the polyether polyurethane resin, which is a water-soluble component in the hydrophilic coating layer, by running water, and was decolorized. Therefore, the desired aesthetic appearance could not be obtained. [Explanation of symbols]

[0092] 1 aluminum plate 2. Coating layer 3. Corrosion-resistant resin coating layer 4 Hydrophilic film layer 5. Undercoating layer 6. Black pigment 10 Aluminum fin material

Claims

1. An aluminum plate having an aluminum plate and a coating layer formed on the surface of the aluminum plate. A miniature fin material, The coating layer is made up of a corrosion-resistant resin coating layer and a hydrophilic coating layer in this order from the aluminum plate side. , and the corrosion-resistant resin coating layer contains a black pigment and a dispersing aid, At least one pigment selected from carbon black, inorganic metal compound pigments, and organic pigments is used as the black pigment, a mass ratio of the black pigment to the total mass of the corrosion-resistant resin coating layer is 35 mass% or less; a mass ratio of the dispersing aid to the mass of the black pigment in the corrosion-resistant resin coating layer is 10 mass% or more; L measured by a spectrophotometer on the aluminum fin material surface ＊ a ＊ b color system Lightness L ＊ An aluminum fin material characterized in that the value is 83 or less.

2. The black pigment is carbon black, and the content of the carbon black per unit area of ​​the corrosion-resistant resin film layer is 0.1 (mg / dm ２ 2. The aluminum fin material according to claim 1, wherein the thickness is 100 mm or more.

3. The aluminum fin material according to claim 1 or 2, characterized in that the corrosion-resistant resin film layer contains at least one selected from epoxy resin, urethane resin, and acrylic resin to which a Zr-based crosslinking agent has been added.

4. The aluminum fin material according to claim 1 or 2, characterized in that the hydrophilic coating layer contains both an acrylic resin and a polyether-based polyurethane resin.

5. The aluminum fin material according to claim 1 or 2, characterized in that a base treatment layer is provided between the aluminum plate and the coating layer.

6. The aluminum fin material according to claim 1 or 2, characterized in that the dispersion aid is made of any one of an acrylic dispersant, a polyester dispersant, and a polyamine dispersant.

Images