JP2011033243A - Fin material for heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fin material for a heat exchanger, which has excellent radiation performance and hydrophilicity, suppresses heat transfer resistance between a tube and the fin material, suppresses die abrasion during treatment to form a fin shape and prevents loss of color when colored. <P>SOLUTION: The fin material includes: a base material 2 made of aluminum or aluminum alloy; and a film 3 applied to the surface of the base material 2 and obtained by burning coating material including polymer molecules and plate-shaped particles 4. The content of the plate-shaped particles 4 in the coating material is set to be 30-200 pts.wt. with respect to 100 pts.wt. of the polymer molecules. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fin material for a heat exchanger such as an air conditioner.

A heat exchanger of an air conditioner (air conditioner) is provided with, for example, a tube and a plurality of heat exchange units made of fin material attached to the tube, so that heat exchange between the refrigerant flowing in the tube and the outside air is performed by fins. It is configured to be performed via a material.
In such a heat exchanger, in order to obtain high heat exchange efficiency, the fin material has high heat dissipation so that the refrigerant can be quickly cooled, and the ventilation resistance of the ventilation path defined by the fin material is small. That is required.

  However, in this type of heat exchanger, condensed water adhering to each fin material during cooling operation becomes water droplets, and a bridge of water between adjacent wall surfaces of the fin material (for example, between adjacent fin materials). When the phenomenon of forming the air is observed, the air passage becomes narrower, so that the resistance to ventilation increases and the heat exchange efficiency decreases.

In order to reduce this kind of decrease in heat exchange efficiency, in heat exchangers, the surface of the fin material is subjected to a hydrophilization treatment in order to impart wettability to the surface of the fin material and to spread the condensed water wet. It is done.
As a hydrophilization treatment method, a method of forming a hydrophilic film by applying and baking sodium silicate (water glass) on the fin material surface (see, for example, Patent Document 1), water resin or silica on a resin There are known methods for forming a hydrophilic film by applying a paint mixed with inorganic particles such as aluminum hydroxide and titania (for example, see Patent Documents 2 to 5).

As another method, there is also known a method of forming a hydrophilic polymer film by appropriately combining hydrophilic polymers such as acrylic resin, polyvinyl alcohol, carboxymethyl cellulose and the like and applying it to the surface of the fin material. This method is known as a method for obtaining hydrophilicity only by organic matter without using inorganic matter. In these fin materials that have been subjected to hydrophilic treatment, water adhering to the surface easily wets and spreads. Hard to occur. For this reason, a bridge of water is rarely formed between the fin members, and ventilation resistance can be suppressed.

However, these hydrophilic treatment methods have the following problems.
First, since the hydrophilic film formed using water glass is hard, there is a problem that when the base material on which the film is formed is processed into a fin shape, the processing mold is remarkably easily worn. In addition, even when a resin mixed with inorganic particles such as water glass or silica is applied to the surface of the base material, due to the hardness of these inorganic substances, the wear of the processing mold is also reduced when the base material is processed into a fin shape. Is likely to be a problem.

  In addition, the method of forming a hydrophilic polymer film on the surface of the substrate often requires a film thickness of 1 μm or more in order to obtain sufficient hydrophilicity. In this case, the fin material is incorporated in the heat exchanger. In this case, since the fin material and the tube are connected via a polymer film of 1 μm or more, the heat transfer resistance between the tube and the fin material is increased, which adversely affects the heat exchange performance of the heat exchanger. End up.

  Further, in such a fin material, a coating film containing a color pigment may be provided in order to improve design properties. Here, when a coloring pigment is contained in the hydrophilic polymer film, there is a problem that the coloring pigment easily flows out to the condensed water adhering to the surface due to high water permeability of the hydrophilic polymer film. As a result, the polymer film is discolored, and the dew condensation water is colored and the drainage portion is colored.

  On the other hand, the heat dissipation of the fin material mainly depends on the thermal characteristics of the material. As a material for the fin material, generally, an aluminum plate or an aluminum alloy plate that has been surface-treated is used, but these aluminum materials themselves are excellent in heat conductivity but are not necessarily high in heat dissipation. That's not true. Here, when the resin mixed with inorganic particles such as water glass or silica as described above is applied to the surface of the aluminum material, the heat dissipation is improved as compared with the unpainted aluminum material. In order to obtain a heat exchanger with higher heat exchange efficiency, it is considered necessary to further improve the heat dissipation of the fin material.

Japanese Patent Publication No.55-1347 Japanese Patent Publication No.57-46000 Japanese Patent Publication No.59-8372 Japanese Examined Patent Publication No. 62-61078 JP-A-61-225044

  The present invention has been made to solve these problems, is excellent in heat dissipation and water wettability, suppresses heat transfer resistance between the tube and the fin material, and at the time of processing into a fin shape. An object of the present invention is to provide a fin material for a heat exchanger in which wear is suppressed and color fading hardly occurs when colored.

  As a result of the inventor's repeated studies to solve the above problems, a hydrophilic film formed by applying and baking a coating material containing a polymer and a plate-like particle in a predetermined ratio on a substrate surface is as follows. , Excellent water wettability can be obtained while keeping the thickness relatively thin, heat of the fin material can be radiated efficiently to the outside, and the plate-like particles are relatively soft, so that the processing mold is worn out. It was found difficult to complete the present invention.

The present invention includes a base material made of aluminum or an aluminum alloy, and a coating film obtained by baking a paint that is applied to the surface of the base material and contains a polymer and plate-like particles. The content of the shaped particles is 30 to 200 parts by weight with respect to 100 parts by weight of the polymer.
In the present invention, the plate-like particles are preferably talc.
In the present invention, the polymer preferably contains a polyvinyl alcohol resin as a main component.
In the present invention, the paint preferably contains an organic titanium compound as a crosslinking agent.
In the present invention, the polymer preferably contains a polyvinyl alcohol resin, and the content of the organic titanium compound in the paint is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin.

According to the present invention, the heat exchanger fin material has a base material and a hydrophilic film obtained by forming and baking a coating film containing a polymer and plate-like particles on the surface of the base material. Configured.
This hydrophilic coating has excellent water wettability reflecting the fact that the plate-like particles are excellent in water wettability. For this reason, in the fin material of the present invention, when water adheres to the surface of the hydrophilic coating, the water easily wets and spreads, and water droplets are hardly generated on the surface. Thereby, it can suppress that the bridge of water is formed between adjacent fin materials.

In addition, the hydrophilic coating of the present invention can obtain sufficient water wettability even when the film thickness is relatively thin by optimizing the combination of the polymer and the tabular grains. When the thickness of the hydrophilic coating is set to be thin, the thickness of the coating interposed between the fin base material and the refrigerant pipe is reduced when the fin material is incorporated into the heat exchanger. The heat transfer resistance can be kept low.
In addition, since the plate-like particles are easily oriented in a substantially horizontal direction with respect to the substrate surface at the time of coating film formation, the hydrophilic coating obtained by this is a plate-like particle in a plan view seen from the substrate side. Occupies a large area. For this reason, in the fin material having the structure of the present invention, the heat of the base material is efficiently radiated to the outside through the plate-like particles, and high heat dissipation can be obtained.

  Furthermore, the plate-like particles contained in the hydrophilic coating are often soft due to their crystal structure. For this reason, when the base material on which the hydrophilic film is formed is processed into a fin shape using the processing mold, it is possible to prevent the processing mold from being worn and the processing performance of the processing mold. Can be maintained over a long period of time.

It is a schematic longitudinal cross-sectional view which shows the fin material for heat exchangers of this invention. It is a schematic diagram which shows the structure of a heat dissipation measuring apparatus. It is a characteristic view which shows the heat dissipation of the fin material produced by each Example and each comparative example.

Hereinafter, specific embodiments of the present invention will be described.
FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a fin material for a heat exchanger according to the present invention.
A fin material 1 shown in FIG. 1 has a base material 2 made of aluminum or an aluminum alloy, and a hydrophilic film 3 coated on the surface of the base material 2.
As the base material 2, a plate material made of aluminum or an aluminum alloy is preferably used because of excellent lightness and workability. These aluminum plates may be subjected to a surface treatment such as phosphoric acid chromate, zirconium phosphate, or anodization in addition to the degreasing treatment. By these surface treatments, the corrosion resistance can be further enhanced.
The shape of the base material 2 is not specifically limited, It selects suitably according to the form of the heat exchanger to which a fin material is applied.

The hydrophilic coating 3 is a coating obtained by applying a coating containing a polymer and the plate-like particles 4 to the surface of a substrate to form a coating and baking the coating. And the content of the plate-like particles 4 in the coating is specified in the range of 30 to 200 parts by weight with respect to 100 parts by weight of the polymer.
Here, the polymer has a function of forming a coating film by holding the plate-like particles 4 and particles such as coloring pigment added as necessary on the surface of the substrate 2.
As the polymer, those having hydrophilicity are preferable, and specific examples include polyvinyl alcohol resins, acrylic resins, epoxy resins, polyurethane resins, and the like, and one or more of these may be combined. Can be used.
When a hydrophilic polymer is used, the hydrophilic coating 3 excellent in water wettability can be obtained reflecting this. Among these, since the polyvinyl alcohol-based resin has high hydrophilicity, the hydrophilic coating 3 using this as a main component of the polymer has a small water contact angle, and water adhering to the surface easily spreads and water droplets are generated. hard. For this reason, even when the space | interval of fin materials is comparatively narrow, it can suppress reliably that the bridge of water is formed between these fin materials.

However, the hydrophilic coating 3 containing a polyvinyl alcohol-based resin as a main component of the polymer has a relatively high water permeability, and therefore, when a coloring pigment described later is added, the coloring pigment adheres to the water adhering to the surface. Elution may cause slight discoloration.
For this reason, when using polyvinyl alcohol-type resin, it is preferable to add an organic titanium compound to a coating material. The organic titanium compound forms a crosslinked structure in the polyvinyl alcohol resin. As a result, a dense network structure is formed in the hydrophilic coating 3, so that the colored pigment is reliably held in the coating 3, and the colored pigment to water attached to the surface of the hydrophilic coating 3 is obtained. Elution can be suppressed.

Examples of the organic titanium compound include titanium lactate, titanium lactate ammonium salt, titanium diisopropoxybis (triethanolaminate), and the like, and these can be used alone or in combination.
As for the addition amount of the organic titanium compound in a coating material, it is desirable that it is 1-20 weight part with respect to 100 weight part of polyvinyl alcohol. When the addition amount of the organic titanium compound is less than 1 part by weight, the effect of suppressing color fading cannot be sufficiently obtained. Moreover, when the addition amount of an organic titanium compound exceeds 20 weight part, the wettability of the hydrophilic coating 3 may fall a little.

In addition, a hydrophilic pigment 3 using a resin (acrylic resin, epoxy resin, polyurethane resin) other than the polyvinyl alcohol-based resin among the above-described hydrophilic polymers as a main component of the polymer is a colored pigment added. Can be reliably held, and elution of the colored pigment into water adhering to the surface can be suppressed.
On the other hand, the water wettability of the hydrophilic coating 3 when these resins are used is inferior to that of a coating containing a polyvinyl alcohol resin as a main component of the polymer (the water contact angle is large), but is relatively good. Has good water wettability. For this reason, if it is a case where the space | interval of adjacent fin materials is made into the comparatively wide state, it can fully suppress that the bridge | bridging of water is formed between these.
The above polymers may be used in combination of two or more. Thereby, the water wettability and the color fading resistance of the hydrophilic coating 3 can be controlled by changing the resin to be selected and the blending ratio of each resin. Thereby, the characteristic of the hydrophilic film 3 can be optimized according to the interval between the adjacent portions of the fin material 1 and the application.

The plate-like particles 4 of this embodiment have a function of imparting water wettability and heat dissipation to the fin material 1. Examples of the plate-like particles 4 of the present embodiment include talc, mica, kaolinite, montmorillonite, and the like, and these can be used alone or in combination.
All of these plate-like particles 4 have excellent water wettability and impart excellent water wettability to the hydrophilic coating 3. Thereby, in the fin material 1, when water adheres to the surface of the hydrophilic coating 3, the water easily wets and spreads, and it is difficult for water droplets to be generated. For this reason, it can suppress that the bridge of water is formed between adjacent fin materials.
Further, since the plate-like particles 4 are plate-like, when the coating material containing the plate-like particles 4 is applied to the surface of the base material 2, as shown in FIG. It tends to be oriented in the direction. For this reason, the hydrophilic film 3 obtained by baking this coating film is in a state where the plate-like particles 4 occupy a wide area in a plan view as viewed from the surface side of the substrate 2. Thereby, since the heat | fever of the base material 2 tends to be efficiently radiated | emitted efficiently outside through the plate-shaped particle | grains 4, the fin material 1 of this embodiment can obtain high heat dissipation.

  The plate-like particles 4 are often soft due to their crystal structure. For this reason, when processing the base material 1 on which the hydrophilic coating 2 is formed into a fin shape using the processing mold, the processing mold can be prevented from being worn, and the processing performance can be reduced. It can be maintained for a long time. Among the materials mentioned above, talc has a very low hardness (Mohs's hardness 1) and also has lubricity, so that the use of talc as the plate-like particles 4 can surely suppress the wear of the processing mold. It can also have excellent heat dissipation.

  In the present embodiment, the content of the plate-like particles 4 in the paint is preferably in the range of 30 to 200 parts by weight with respect to 100 parts by weight of the polymer. When the content of the plate-like particles 4 is less than 30 parts by weight, the effect of adding the plate-like particles 4 (effect of improving water wettability and heat dissipation) cannot be obtained sufficiently. Moreover, when the content of the plate-like particles 4 exceeds 200 parts by weight, the adhesion between the hydrophilic coating 3 and the substrate 2 and the strength of the hydrophilic coating 3 are reduced, and the coating film is peeled off and applied during processing by the mold. Problems such as film scraping will occur. Further, if the content of the plate-like particles 4 is large, there is a problem that even if the hydrophilic coating 3 is colored, the color of the plate-like particles 4 is not vividly developed and the color tone is changed.

The particle size of the plate-like particles 4 is not particularly limited, but the average diameter of the flat portion is preferably 5 μm or less, the maximum diameter is preferably 10 μm or less, and the average diameter is more preferably 2 to 3 μm. Here, the “average diameter” is an average value of the long diameter (maximum diameter) and the short diameter (minimum diameter) in the plane portion, that is, the value of (maximum diameter + minimum diameter) / 2.
When the average diameter in the plane portion exceeds 5 μm, or when the maximum diameter exceeds 10 μm, the base on which the hydrophilic coating 3 is formed depends on the type and content of the polymer or the plate-like particle 4. When the material 2 is processed by a mold, the plate-like particles 4 may be easily peeled off. On the other hand, the plate-like particles 4 having an average diameter smaller than 2 μm are difficult to obtain and expensive, lacking versatility, and when the average diameter is too small, the plate-like particles 4 are arranged in parallel to the surface of the fin material 1 at the time of application. It tends to be difficult.
Further, it is preferable to use a plate-like particle 4 having a thickness in the range of 0.001 μm to 0.05 μm.

The hydrophilic coating 3 is obtained by supplying a coating containing the polymer as described above and the plate-like particles 4 to the surface of the substrate to form a coating, and baking the coating.
Specifically, the coating material can be prepared by adding and dispersing the plate-like particles 4 in a solution (polymer solution) in which a polymer is dissolved.
Here, the plate-like particles 4 may be added directly to the polymer solution, or may be added to the polymer solution in a state of being previously dispersed in water or an organic solvent.
The dispersion of the plate-like particles 4 may be performed by stirring, or may be performed using an apparatus that disperses by vibration such as a shaker, or a dispersion apparatus that also serves as pulverization such as a ball mill.

Moreover, you may add a color pigment to a coating material as needed.
The coloring pigment imparts a hue to the hydrophilic coating 3. When the hydrophilic coating 3 has a hue, the design of the fin material 1 is improved. Further, for example, if the hue of the hydrophilic coating 3 is changed depending on the type, grade, etc. of the substrate 2, the effect that the type, grade, etc. of the substrate 2 can be easily discriminated by the hue can be obtained.
An organic pigment or an inorganic pigment can be used as the pigment, or a single pigment or a combination of a plurality of pigments can be used according to the target hue. This color pigment may be added directly to the polymer solution, or may be added to the polymer solution in a state of being previously dispersed in water or an organic solvent.

  Furthermore, you may add the additive which prevents precipitation of the plate-shaped particle 4 to a coating material. Examples of such additives include sodium polyacrylate, various surfactants, alkali metal silicates, and the like, and one or more of these can be used in combination. In particular, the addition of such an additive is effective because the plate-like particles 4 having a large particle size are easily precipitated in the paint and difficult to uniformly disperse. In addition, it is preferable to set the addition amount of an additive in the range which does not affect the performance (hydrophilicity, heat dissipation, etc.) of the hydrophilic film 3. FIG.

  Although the thickness of a coating film is not specifically limited, It is desirable that it is 1 micrometer or less. When the thickness of the coating film exceeds 1 μm, the thickness of the hydrophilic coating film 3 obtained by baking the coating film also increases. As a result, when the fin material 1 is incorporated in the heat exchanger, the tube and the fin base 2 are connected via the relatively thick coating 3, and the heat transfer resistance between the tube and the fin material 1 is reduced. growing. Moreover, when the thickness of the coating film is too thin, the effect of providing the hydrophilic coating 3 cannot be sufficiently obtained. From the above viewpoint, it is desirable that the thickness of the coating film is set to about the lower limit of the thickness range where necessary hydrophilicity can be obtained.

  The baking conditions vary depending on the type of polymer contained in the coating film, and baking may be performed at an optimum temperature and baking time depending on the type of polymer. Note that the optimum conditions for baking are almost independent of the type of the plate-like particles 4 and are determined by the type of polymer.

As described above, in the fin material 1, the hydrophilic coating 3 obtained by baking the coating containing the polymer and the plate-like particles 4 is provided on the surface of the substrate 2.
Such a hydrophilic coating 3 can impart excellent water wettability to the surface thereof by using the plate-like particles 4 excellent in water wettability. Thereby, in this fin material 1, when water adheres to the surface of the hydrophilic coating 3, the water easily wets and spreads, so that water droplets are hardly generated and a water bridge is formed between the fin materials. Can be suppressed.

  In addition, the hydrophilic coating 3 can obtain sufficient water wettability even when the film thickness is relatively thin by optimizing the combination of the polymer and the tabular grains 4. When the thickness of the hydrophilic film 3 is set to be thin, the thickness of the film 3 interposed between the fin base material 2 and the tube is reduced when the fin material 1 is incorporated in the heat exchanger. Heat transfer resistance between materials can be kept low.

  Further, the plate-like particles 4 are oriented in a substantially horizontal direction with respect to the surface of the substrate 2 at the time of coating film formation, and the hydrophilic coating 3 obtained thereby has a plate-like shape in plan view as viewed from the substrate 2 side. The particles 4 occupy a large area. For this reason, in this fin material 1, the heat of the base material 2 is efficiently radiated to the outside through the plate-like particles 4, and high heat dissipation can be obtained.

  Furthermore, many of the plate-like particles 4 are soft due to their crystal structure. For this reason, when the base material 1 on which the hydrophilic coating 3 is formed is processed into a fin shape using the processing mold, it is possible to prevent the processing mold from being worn by particles in the coating. For this reason, the performance of the processing mold can be maintained over a long period of time.

This fin material is excellent in heat dissipation because the hydrophilic coating can efficiently radiate the heat of the base material. For this reason, the heat transfer between the fin and the atmosphere is good, and the heat of the refrigerant flowing in the tube can be efficiently transmitted to the fin and dissipated.
Further, since the hydrophilic coating 3 is excellent in water wettability, water attached to the surface of the fin (hydrophilic coating) easily spreads and flows down, and water droplets are hardly generated. For this reason, it is suppressed that the bridge of water is formed between the adjacent wall surfaces of the fin, and the ventilation resistance of the air ventilation path can be suppressed to be small.
By these actions, this heat exchanger can obtain high heat exchange efficiency.
As mentioned above, although embodiment of the fin material for heat exchangers of this invention was described, each part which comprises the said fin material for heat exchangers is an example, Comprising: It can change suitably in the range which does not deviate from the range of this invention.

Specific examples of the present invention will be described below, but the present invention is not limited to these examples.
<Production of fin material>
Example 1
First, a coating material was prepared by mixing and dispersing 100 parts by weight of polyvinyl alcohol (PVA), 100 parts by weight of plate-like talc particles (average particle size 2 μm, thickness 0.01 μm) and a phthalocyanine pigment. The amount of the phthalocyanine pigment was adjusted so that the b ^* value when the coating film was measured with a color difference meter was -5.
Next, an aluminum plate subjected to a phosphoric acid chromate treatment was prepared, and a coating film (thickness 5 μm) was formed by applying a paint to the surface.
Next, this coating film was baked by heat-treating at a temperature of 210 ° C. for 60 seconds to form a hydrophilic coating (film thickness: 0.7 μm).
The fin material was created by the above process.

(Examples 2 and 3)
A fin material was prepared in the same manner as in Example 1 except that the amount of talc particles mixed in the paint was changed as shown in Table 1.
(Examples 4 to 8),
A fin material was prepared in the same manner as in Example 1 except that the type and amount of inorganic particles to be mixed in the coating material were selected as shown in Table 1, and the organic titanium compound shown in Table 1 was added to the coating material.
The organic titanium compound used is titanium lactate (TL), titanium lactate ammonium salt (TL ammonium salt), or titanium diisopropoxybis (triethanolaminate) (TDIPTA).
(Examples 9 and 10)
A fin material was prepared in the same manner as in Example 1 except that the type of inorganic particles mixed in the paint was changed to that shown in Table 1.
(Examples 11 to 15)
A fin material was prepared in the same manner as in Example 1 except that the type of polymer mixed in the paint, the type and amount of inorganic particles, and the baking temperature of the coating film were as shown in Table 1.

(Comparative Examples 1 to 5)
A fin material was prepared in the same manner as in Example 1 except that the types and amounts of the inorganic particles to be mixed in the paint were as shown in Table 1.

<Evaluation>
About the fin material produced in each Example and each comparative example, water wettability, color fading resistance, metal mold | die abrasion property, and heat dissipation were evaluated. The evaluation conditions are as shown below.
1. Water wettability Each fin material was cooled to 5 ° C. by being attached to a cooling plate in an environment of a temperature of 40 ° C. and a humidity of 80%, and the dew condensation state at that time was visually observed. The observation results were evaluated according to the following criteria.
A: Wetting is observed on the entire surface of the coating.
○: Although the film is entirely wetted, a portion that is not wetted is recognized.
Δ: Most of the film is wet, but some water droplets are observed.
X: Many water droplets are generated.

2. Color fading resistance Each sample obtained by cutting each fin material to a size of 2000 cm ² was immersed in 1000 ml of water for 10 minutes. Thereafter, this water was concentrated to 10 ml, and the absorbance at a wavelength of 430 nm was measured using a 10 mm-thick cell for this concentrated water. The measurement results were evaluated according to the following criteria.
◎: Absorbance is less than 0.01 ○: Absorbance is 0.01 or more and less than 0.02 ×: Absorbance is 0.02 or more

3. Mold Abrasion Resistance Each fin material was cut 1 million times using a shearing mold made of powdered high speed tool steel (HRC60), and then the wear state of the mold was observed. In addition, when the wear of the mold progressed and cutting was impossible, the evaluation was stopped at that time. The observation results were evaluated according to the following criteria.
A: Mold wear is hardly recognized.
○: Slight mold wear is recognized.
Δ: The mold is considerably worn.
X: The mold wear progresses rapidly and cannot be cut 1 million times.

4). Heat dissipation Heat dissipation was evaluated using a heat dissipation measuring device shown in FIG.
The heat dissipation measuring device 101 includes a heat insulating container 102 having an open top, a thermocouple 103 penetrating through a side wall of the heat insulating container 102, and a heat sensitive part inserted into the heat insulating container 102, and a thermocouple 103. A temperature recorder 104 for recording the measured temperature is used.

  First, the fin material 1 is placed on the heat insulating container 102, and the heat insulating container 102 is carried into an oven and heated. Then, when the temperature measured by the thermocouple 103 (temperature in the heat insulation container) reaches 80 ° C., the heat insulation container 102 is taken out into the room at a temperature of 20 ° C., and immediately after that, the temperature change in the heat insulation container 102 ( The temperature change with time measured by the thermocouple 103 was observed. The result is shown in FIG.

  As shown in Table 2, all the fin materials produced in each example were excellent in water wettability and color fading resistance, and mold wear was also suppressed. In particular, fin materials (Examples 4 to 6 and 8) using polyvinyl alcohol as a polymer and added with an organic titanium compound were able to obtain particularly excellent water wettability and color fading resistance.

In addition, as shown in FIG. 3, the fin materials produced in each of the examples all have excellent heat dissipation because the temperature dropped at a rate of about 15 ° C. for 10 seconds in the above-described heat dissipation test. Was.
On the other hand, the fin materials of Comparative Examples 1, 2, and 5 that do not use plate-like inorganic particles and Comparative Example 3 with a small amount of inorganic particles are the same in the above heat dissipation test (see FIG. 2). Compared to the examples, the temperature drop was small (about 10 ° C. for 10 seconds), and the heat dissipation was inferior.

Further, as shown in Table 2, the fin material of Comparative Example 3 has insufficient water wettability, and the fin material of Comparative Example 5 has insufficient water wettability and inferior color fading resistance. It was.
Furthermore, the fin material of Comparative Example 4 having a large amount of inorganic particles had low color fading resistance. In the sample of Comparative Example 4, talc was hardened on the surface of the hydrophilic coating, and the coating peeled when the fin material was cut in the mold wear test.

  DESCRIPTION OF SYMBOLS 1 ... Fin material, 1A ... Fin, 2 ... Base material, 3 ... Hydrophilic film | membrane (film), 4 ... Plate-like particle | grain.

Claims (5)

A base material made of aluminum or an aluminum alloy, and a coating obtained by baking a paint containing a polymer and plate-like particles applied to the surface of the base material;
The heat exchanger fin material, wherein the content of the plate-like particles in the paint is 30 to 200 parts by weight with respect to 100 parts by weight of the polymer.   The fin material for a heat exchanger according to claim 1, wherein the plate-like particles are talc.   The heat exchanger fin material according to claim 1, wherein the polymer contains a polyvinyl alcohol-based resin as a main component.   The fin material for a heat exchanger according to any one of claims 1 to 3, wherein the coating contains an organic titanium compound as a crosslinking agent.   5. The polymer according to claim 4, wherein the polymer contains a polyvinyl alcohol resin, and the content of the organic titanium compound in the paint is 1 to 20 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. The fin material for heat exchangers as described.

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