JP2017155973A - Fin material for heat exchanger and heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fin material for a heat exchanger showing a superior hydrophilic property and capable of restricting adsorption of higher alcohol type contaminant and provide a heat exchanger using the fin material.SOLUTION: This invention relates to a base plate 2 made of aluminum and a coated film 3 made of one layer or two layers or more films formed on it and a heat exchanger using them. The coated film 3 has a hydrophilic film 31 at its outermost surface. A solid surface tensile force polarity component of the hydrophilic film 31 calculated by Fowkes expansion formula expressed by the following equation [I]. γmN/m and a solid surface tension hydrogen bond component γmN/m satisfy a relation of 35≤γ≤100 and γ+γ≥60.γ(1+cosθ)=2(γ×γ)+2(γ×γ)+2 (γ×γ)***(I)SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fin material used in a heat exchanger and a heat exchanger using the same.

  In recent years, heat exchangers for air conditioners are required to improve heat exchange efficiency and be compact, and the heat transfer area per volume is increased by shortening the fin interval. For example, in an indoor unit during cooling operation, when moisture in the air that contacts the surface of the fin made of a metal material is cooled to a dew point or less, it adheres to the surface of the fin as condensed water. Here, since the surface of the metal material is generally poor in hydrophilicity, the condensed water stays on the fin surface in a semicircular shape or as a bridge between the fins. As a result, the ventilation resistance, that is, the resistance value of the airflow passing between the fins increases, and as a result, the heat exchange efficiency decreases. Therefore, the fin surface is required to have a surface treatment for quickly draining condensed water.

  As a solution to this, by forming a hydrophilic film on the fin surface and making the condensed water a uniform and thin water film, the drainage is improved, the increase in ventilation resistance due to the condensed water is suppressed, and the heat exchange performance The technique to maintain is adopted. For example, a method has been proposed in which chromate treatment is applied to the fin surface to form an inorganic film containing silica such as water glass or colloidal silica, or an organic film containing a hydrophilic polymer such as cellulose resin or acrylic resin. Yes.

  On the other hand, recently, during the operation of an indoor unit such as an air conditioner, a water splash phenomenon (also referred to as a “dew jump phenomenon”) in which water droplets scatter from the air outlet has become a problem. This is considered to occur because contaminants floating in the indoor space adhere to the fin surface and make the surface water repellent. Examples of contaminants that cause such water repellency include higher alcohols such as hexadecanol and octadecanol. Higher alcohol is also included in cosmetics such as lubricants for machine nuts and bolts, moisturizing creams, etc., so it is said that a lot of water splashing occurs in beauty salons and offices with many female employees. Yes. In order to prevent such a water jump phenomenon, an aluminum fin material having an effect of suppressing the adhesion of higher alcohol-based contaminants has been developed (see Patent Documents 1 and 2).

  For example, in the aluminum fin material of Patent Document 1, the hydrophilic coating film containing a predetermined amount or more of a polyvinyl alcohol-based resin suppresses adhesion of higher alcohol-based pollutants and realizes anti-dew resistance. Further, in the aluminum fin material of Patent Document 2, dew resistance is realized by a hydrophilic film containing a hydrophilic resin such as polyacrylic acid and a silicone compound.

JP 2011-94873 A JP 2013-210144 A

  However, although the fin material of Patent Document 1 can suppress adhesion of higher alcohol-based contaminants, further improvement is desired. In Patent Document 1, since a low-polarity polyvinyl alcohol-based resin is used for the hydrophilic coating film and the degree of saponification is 0.9 or more, there is room for further improvement in hydrophilicity. In addition, in the fin material of Patent Document 2, a hydrophilic film containing a highly polar hydrophilic resin such as polyacrylic acid and a nonpolar silicone compound has a significantly reduced solid surface tension. Therefore, it is difficult to achieve both the suppression of contaminant adhesion and hydrophilicity. Therefore, when the conventional fin material is used for the fins of the heat exchanger, there is a possibility that a water splash phenomenon may occur. In addition, water droplets condensed between the fins may bridge and increase the ventilation resistance.

  The present invention has been made in view of such problems, and provides a fin material for a heat exchanger that is excellent in hydrophilicity and can suppress adsorption of higher alcohol-based contaminants, and a heat exchanger using the same. It is something to try.

One embodiment of the present invention is a substrate made of aluminum;
A coating formed of one or two or more layers formed on the substrate, and the coating has a hydrophilic coating on the outermost surface,
The solid surface tension polar component γ _S ^p mN / m and the solid surface tension hydrogen bonding component γ _S ^h mN / m of the hydrophilic film calculated from the Fowkes expansion formula represented by the following formula (I) are 35 ≦ The heat exchanger fin material satisfies the relationship of γ _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60.
γ _L (1 + cos θ _L ) = 2 (γ _s ^d × γ _L ^d ) ^1/2 +2 (γ _s ^p × γ _L ^p ) ^1/2 +2 (γ _s ^h × γ _L ^h ) ^1/2. I)
γ _L : surface tension of contact medium γ _L ^d : surface tension dispersion component of contact medium γ _L ^p : surface tension polar component of contact medium γ _L ^h : surface tension hydrogen bond component of contact medium γ _s ^d : solid surface tension dispersion Component γ _s ^p : Solid surface tension polar component γ _s ^h : Solid surface tension hydrogen bonding component

  Another aspect of the present invention is a heat exchanger provided with fins made of the fin material.

The fin material has a solid surface tension polar component γ _S ^p [unit: mN / m] and a solid surface tension hydrogen bond component γ _S ^h [unit: mN / m] of the hydrophilic film formed on the outermost surface of 35. ≦ γ _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60 are satisfied. That is, by reducing the component gamma _S ^p of the hydrophilic film selectively below a predetermined value, and reduces the polarity of the hydrophilic film surface. Therefore, it becomes possible to sufficiently suppress the adsorption of the higher alcohol. Furthermore, even if higher alcohol adheres to the surface of the hydrophilic film, condensed water easily enters between the bond between the film and the higher alcohol, and the higher alcohol is easily washed away by the condensed water. Therefore, water repellency on the surface of the film can be prevented. Furthermore, since the sum of the component γ _S ^p and the component γ _S ^h and the component γ _S ^p are adjusted to the predetermined value or more, high hydrophilicity can be obtained.

  As described above, the fin material has both a higher alcohol adsorption suppressing effect and excellent hydrophilicity. Therefore, the heat exchanger provided with such a fin material can prevent the water jumping phenomenon. Furthermore, the thickness of the water film on the dew condensation water on the hydrophilic film is reduced and uniform, so it is possible to improve the removal of adhering higher alcohols and to sufficiently suppress the formation of bridges between the fins of the dew condensation water. can do.

Sectional drawing of the fin material which has a board | substrate and a hydrophilic membrane | film | coat in an Example. Sectional drawing of the fin material which has a board | substrate in Example 1, a corrosion-resistant film | membrane, and a hydrophilic film | membrane. 1 is a schematic diagram illustrating a configuration of a contamination resistance evaluation apparatus in Embodiment 1. FIG. FIG. 3 is a schematic diagram of a heat exchanger in Embodiment 2.

An embodiment of a fin material and a heat exchanger using the same will be described.
The fin material has a substrate made of aluminum. In this specification, “aluminum” is a generic term for metals and alloys mainly composed of aluminum, and is a concept including pure aluminum and aluminum alloys.

  The coating film formed on the substrate has one layer or two or more layers. The coating film formed by applying the same type of coating material once is one layer, but the coating film formed by repeatedly applying the coating material having the same component composition a plurality of times is also one layer. The coating film has a hydrophilic film on the outermost surface.

In the hydrophilic film, the polar component γ _S ^p mN / m of the solid surface tension and the hydrogen bonding component γ _S ^h mN / m satisfy the relationship of 35 ≦ γ _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60. Satisfied. By satisfying these relationships, hydrophilicity can be enhanced while suppressing an increase in the polarity of the hydrophilic film. As a result, the hydrophilic film can achieve both a higher alcohol adsorption suppressing effect and hydrophilicity at a high level. From the viewpoint of further improving the adsorption suppression effect, γ _S ^p ≦ 90 is preferable, and γ _S ^p ≦ 85 is more preferable. From the viewpoint of further improving the hydrophilicity, γ _S ^p ≧ 45 is preferable, and γ _S ^p ≧ 50 is more preferable. As for the γ _S ^p + γ _S ^h, from the viewpoint of further improving the hydrophilicity, preferably ^{_{γ S p + γ S h ≧}} 90, γ S p + γ S h ≧ 100 it is more preferable. From the viewpoint of achieving both hydrophilicity and adsorption suppression effect at a higher level, γ _S ^p and γ _S ^h are preferably close to each other, and the relationship of γ _S ^p −γ _S ^h ≦ 50 is satisfied. It is more preferable that the relationship of γ _S ^p −γ _S ^h ≦ 30 is satisfied.

When γ _S ^p <35 or γ _S ^p + γ _S ^h <60, hydrophilicity may be insufficient, and when γ _S ^p > 100, higher alcohol may be easily adsorbed. is there. Γ _S ^p and γ _S ^p + γ _S ^h of the hydrophilic film can be controlled by adjusting the composition of the film, for example.

In Fowkes expandable represented by the above formula (I), the solid surface tension of the dispersion ingredients gamma _s ^d, a polar component gamma _s ^p, the hydrogen bond component gamma _s ^h, contact media surface tension gamma _L, variance components gamma _L ^d , (a) water, (b) ethylene glycol, and (c) diiodomethane, which are media having known values of the polar component γ _L ^p and the hydrogen bond component γ _L ^h , are respectively dropped onto the surface of the hydrophilic film. And can be calculated by measuring the contact angle. Each value (γ _L , γ _L ^d , γ _L ^p , γ _L ^h ) of the surface tension of each medium is as follows. These units are all mN / m.
(A) Water: γ _L / γ _L ^d / γ _L ^p / γ _L ^h = 72.8 / 29.1 / 1.3 / 42.4
(B) Ethylene glycol: γ _L / γ _L ^d / γ _L ^p / γ _L ^h = 47.7 / 30.1 / 0 / 17.6
(C) Diiodomethane: γ _L / γ _L ^d / γ _L ^p / γ _L ^h = 50.8 / 46.8 / 4.0 / 0

  From the viewpoint of further improving the removal of higher alcohol and further suppressing bridge formation due to dew condensation water between the fins, the water contact angle of the hydrophilic film is preferably 30 ° or less, more preferably 25 ° or less, and 15 °. The following is more preferable.

The hydrophilic film can contain a hydrophilic resin whose main component is a structural unit derived from a monomer having a hydroxyl group. Examples of such hydrophilic resins include vinyl alcohol resins such as polyvinyl alcohol having a structural unit represented by the following formula (1), and celluloses such as carboxymethyl cellulose having a structural unit represented by the following formula (2). Of these, a silanol resin having a structural unit represented by the following formula (3) is preferred. Note that n in the formulas (1) to (3) is an arbitrary natural number appropriately determined according to the molecular weight of each available resin. Further, R ¹ to R ³ in Formula (2) each independently represent OH or CH ₂ COOH, R ¹ in the formula (3) represents H or CH _3.

The hydrophilic film contains at least one hydrophilic resin (A) selected from the group consisting of a vinyl alcohol resin, a cellulose resin, and a silanol resin in a solid content mass ratio of 70% or more, and has a perfluoroalkyl group. It is preferable to contain 0.6 to 5% of the fluorine-based compound (B) having a solid content mass ratio. In this case, a hydrophilic film satisfying the above-described relationship of 35 ≦ γ _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60 can be easily obtained. Specifically, the sum of the polar component γ _S ^p and the hydrogen bonding component γ _S ^h of the solid surface tension is increased by increasing the abundance ratio of the hydrophilic resin (A) having a low polar component above the predetermined value. It is possible to reduce the ratio of the polar component γ _S ^{p to} the solid surface tension while suppressing the decrease in. Further, by adding a fluorine compound having a perfluoroalkyl group in a weight ratio within the predetermined range, while suppressing the decrease in the sum of the polar component gamma _S ^p and hydrogen bond component gamma _S ^h, polar component gamma _S ^p Can be selectively reduced. As a result, a hydrophilic film satisfying the above relationship can be easily obtained. Incidentally, the higher the solid content mass ratio of the hydrophilic resin (A), the polar component gamma _S ^p tends to be low.

  The saponification degree of a vinyl alcohol resin such as polyvinyl alcohol is preferably 0.9 or more, and the etherification degree of a cellulose resin such as carboxymethyl cellulose is preferably 0.6 or more. In these cases, it is possible to suppress the vinyl alcohol resin and the cellulose resin from being dissolved in the condensed water. Therefore, the durability of the hydrophilic film can be further improved.

It is preferable that the hydrophilic film further contains at least one kind obtained from the group consisting of polyacrylic acid, polyacrylate, and polyethylene glycol resin. When at least one of polyacrylic acid and polyacrylate is contained, the hydrophilicity can be further improved. When the polyethylene glycol resin is contained, the lubricity can be further improved. Examples of the polyethylene glycol-based resin include polyethylene glycol and polyethylene oxide. For example, polyacrylic acid and polyacrylate have a structural unit represented by the following formula (4), and R ^{1 in the} formula (4) represents H, Na, and NH ₂ . The polyethylene glycol resin is represented by, for example, the following formula (5). Note that n in the formulas (4) and (5) is an arbitrary natural number that is appropriately determined according to the molecular weight of each available resin.

The hydrophilic film preferably contains a crosslinking agent comprising at least one of a blocked isocyanate compound and a melamine resin. Also in this case, a hydrophilic film satisfying the relationship of 5 ≦ γ _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60 can be easily obtained. Further, in this case, curing of the coating film is accelerated, corrosion resistance and moisture resistance are improved, and an effect of suppressing corrosion of the aluminum plate is obtained.

  Although the thickness of a hydrophilic membrane | film | coat can be adjusted suitably, it can be 0.5-2 micrometers, for example. It is preferable that the hydrophilic film contains at least one of an antibacterial agent and an antifungal agent. In this case, in this case, the antibacterial and antifungal properties of the hydrophilic film can be improved.

  The coating film preferably has a corrosion-resistant film containing at least one resin selected from the group consisting of an acrylic resin, an epoxy resin, a urethane resin, and an ester resin between the hydrophilic film and the substrate. . In this case, the corrosion resistance of the fin material can be further improved. The thickness of the corrosion resistant film can be adjusted to a range of 0.3 to 5 μm, for example. If the thickness of the corrosion-resistant film is too small, the corrosion resistance may not be sufficiently secured, and if the thickness is too large, the heat transfer performance of the fin material may be reduced.

  A base treatment layer made of a chemical conversion film can be provided between the coating film and the substrate. In this case, the adhesion between the coating film and the substrate can be improved. Furthermore, the corrosion resistance of the fin material can be improved, and the under-film corrosion caused when corrosive substances such as water and chlorine compounds permeate the surface of the substrate is suppressed to prevent film cracking and film peeling. Can do.

Examples of chemical coatings include chemical coatings such as chromate treatment such as phosphate chromate and chromate chromate, and non-chromate treatment using titanium phosphate, zirconium phosphate, molybdenum phosphate, zinc phosphate, zirconium oxide, etc. other than chromium compounds. A film obtained by treatment, so-called chemical conversion treatment, can be employed. The chemical conversion treatment methods such as chromate treatment and non-chromate treatment include a reaction type and a coating type, and any method may be used. The base treatment layer can be formed at 100 mg / m ² or less.

  The water contact angle of the hydrophilic film is preferably 30 ° or less. In this case, the surface of the fin material can exhibit sufficiently excellent hydrophilicity. In addition, the water contact angle on the surface of the hydrophilic film is as described above even immediately after the production of the fin material, even after the higher alcohol is adsorbed on the surface and washed with water, as in the later-described contamination resistance evaluation test. It is preferable that it is 30 degrees or less. More preferably, it is 25 ° or less.

  The fin material is used for manufacturing a heat exchanger as follows, for example. Specifically, first, a coil-shaped fin material is cut into a predetermined size to obtain a plurality of plate-shaped fins. Next, the press machine performs slit processing, louver molding, and color processing on the fin. Next, a plurality of fins are stacked and arranged in a state of being spaced apart from each other while passing the metal tube arranged at a predetermined position through a hole provided in the fin. Thereafter, the metal tube and the fin are brought into close contact with each other by inserting a tube expansion plug into the metal tube to increase the outer diameter of the metal tube. In this way, a heat exchanger can be obtained. A heat exchanger can be used for an indoor unit and an outdoor unit of an air conditioner, for example, and is particularly suitable for an indoor unit.

Example 1
In this example, fin materials (sample E1 to sample E18) according to an example of the present invention and fin materials (sample R1 to sample R6) according to a comparative example are manufactured and their characteristics are evaluated. As shown in FIG. 1, the fin material 1 (sample E1 to sample E14) of sample E1 to sample E14 has a substrate 2 made of aluminum and a coating film 3 formed on the surface thereof. The coating film 3 is composed of a hydrophilic film 31. A chemical conversion film 4 is formed between the substrate 2 and the coating film 3. The laminated structure of the films of Samples R1 to R6 is the same as Samples E1 to E14.

  In addition, as shown in FIG. 2, the fin material 1 of the samples E15 to E18 has a hydrophilic film 31 and a corrosion-resistant film 32 as the coating film 3, and the outermost layer is made of the hydrophilic film 31. Other configurations are the same as those of the samples E1 to E14. That is, the fin material 1 of the sample E15 to the sample E18 was formed on the substrate 2, the chemical conversion film 4 formed on the substrate 2, the corrosion resistant film 32 formed on the chemical conversion film 4, and the corrosion resistant film 32. A hydrophilic film 31.

Sample E1~ Sample E18 and Sample R1~ samples R6 is different constituents of the hydrophilic film 31 as shown in Tables 1 and 2 below each other, the solid surface tension polar component gamma _S ^p and the solid surface of the hydrophilic film 31 The tensile hydrogen bonding components γ _S ^h are different from each other.

  Hereinafter, the manufacturing method of fin material (sample E1-sample E14) is demonstrated. First, an aluminum plate having JIS A 1050-H26 and a plate thickness of 0.1 mm was prepared as the substrate 2. By performing a chemical conversion treatment on the substrate 2, a chemical conversion film 4 made of phosphate chromate was formed on the surface of the substrate 2.

  Next, a coating having a predetermined composition (see Table 1) is applied onto the chemical conversion film 4 using a bar coater, and heated at a temperature of 225 ° C. for 10 seconds, thereby forming a coating film made of a hydrophilic film 31 having a thickness of 1 μm. 3 was formed. Thus, the fin material 1 was obtained as shown in FIG. Each of the samples E1 to E14 is manufactured by the same method as described above except that the composition of the paint for forming the hydrophilic film is different. The same applies to the samples R1 to R6.

  Further, the fin materials of Samples E15 to E18 were manufactured as follows. First, the chemical conversion film 4 was formed on the substrate 2 in the same manner as the samples E1 to E14. Next, a coating containing a predetermined resin component (see Table 1) was applied on the chemical conversion film 4 and heated at a temperature of 225 ° C. for 10 seconds to form a corrosion-resistant film 32 having a thickness of 1 μm. After air cooling, a coating having a predetermined composition (see Table 1) was applied onto the corrosion-resistant film 32 using a bar coater, and heated at a temperature of 225 ° C. for 10 seconds to form a hydrophilic film 31 having a thickness of 1 μm. . Thus, the fin material 1 was obtained as shown in FIG.

In Table 1, the constituent components of the hydrophilic film and the type of resin of the corrosion-resistant film are indicated by abbreviations, and the meaning of each abbreviation is as follows.
(1) Hydrophilic resin A
A1: Polyvinyl alcohol (K-50 manufactured by Denka Co., Ltd.)
A2: Silanol resin (MS51 manufactured by Mitsubishi Chemical Corporation)
A3: Carboxymethylcellulose (Serogen 7A manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

(2) Compound B
B1: Fluorine compound; perfluoroalkyl acrylate (F-6130 manufactured by Fluoro Technology Co., Ltd.)
B2: Silicone compound (x-52-2162 manufactured by Shin-Etsu Chemical)

(3) Resin C
C1: Polyacrylic acid (SY31-5A manufactured by Mitsui Chemicals, Inc.)
C2: Polyethylene glycol (PEG200000 manufactured by Sanyo Chemical Industries)
C3: Polyethylene oxide (PEO-27P manufactured by Sumitomo Seika Co., Ltd.)

(4) Additive D
D1: Cross-linking agent; melamine resin (Symel 350 manufactured by Mitsui Chemicals, Inc.)
D2: antibacterial agent; zinc pyridione (DP-2479 manufactured by Nippon Soda Co., Ltd.)

(5) Corrosion resistant resin P
P1: Acrylic resin (Jurimer manufactured by Toagosei Co., Ltd.)
P2: Acrylic modified epoxy resin (MODEPICS-304 manufactured by Arakawa Industry Co., Ltd.)
P3: Urethane resin (Adekabon titer HUX-370 manufactured by ADEKA Corporation)
P4: Ester resin (water dispersion type polyester WR-960 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)

Next, the surface tension of the fin material of each sample was measured. Specifically, first, each fin material was cut into 50 mm × 100 mm to prepare test plates. Next, 1 μl each of water, ethylene glycol, and diiodomethane was dropped on the hydrophilic film of the test plate, and the contact angle 15 seconds after the dropping was measured by the θ / 2 method. For the measurement, an automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. was used. Based on the measured value of the contact angle, the surface tension was determined by the Fowkes expansion formula represented by the following formula (I). The results are shown in Table 1.
γ _L (1 + cos θ _L ) = 2 (γ _s ^d × γ _L ^d ) ^1/2 +2 (γ _s ^p × γ _L ^p ) ^1/2 +2 (γ _s ^h × γ _L ^h ) ^1/2. I)
γ _L : surface tension of contact medium γ _L ^d : surface tension dispersion component of contact medium γ _L ^p : surface tension polar component of contact medium γ _L ^h : surface tension hydrogen bond component of contact medium γ _s ^d : solid surface tension dispersion Component γ _s ^p : Solid surface tension polar component γ _s ^h : Solid surface tension hydrogen bonding component

  Next, the stain resistance and hydrophilicity of the fin material of each sample were evaluated in the following procedure. The results are shown in Table 2.

<Contamination resistance>
The contamination resistance was evaluated by measuring the occupation ratio of higher alcohol (specifically hexadecanol) adsorbed on the hydrophilic film of each sample. Specifically, first, each sample was cut into 50 mm × 100 mm to prepare a test plate. Next, the test plate was immersed in flowing water at a temperature of 25 ° C. and a flow rate of 5 L / hour for 1 hour, and then sufficiently dried.

  Next, as shown in FIG. 3, a sealed bottle 60 with a volume of 5 L was prepared, and an aluminum cup 61 containing 3 g of hexadecanol was placed at the bottom of the sealed bottle 60. Further, a wire 62 extending in the diametrical direction was stretched on the top of the closed bottle, and a wire 63 was hung from the wire 62 toward the bottom of the closed bottle. Then, each test plate 1 was attached to the end of the wire 63. Next, the sealed bottle 60 was placed in an oven heated to a temperature of 80 ° C. and heated for 16 hours to adhere hexadecanol to the surface of the test plate (operation a). Next, the test plate 1 taken out from the sealed bottle 60 was immersed in running water at a temperature of 25 ° C. and a flow rate of 5 L / hour for 8 hours, and then sufficiently dried (operation b). As a reference test, each test plate was heated in an oven at 80 ° C. for 16 hours (operation c). About each test plate after operation a, operation b, and operation c, the water contact angle in the surface of a hydrophilic membrane | film | coat was each measured. The method for measuring the water contact angle is the same as the water contact angle at the time of measuring the surface tension.

Next, the occupation ratio of the adhesion area of hexadecanol was calculated from the Cassie's formula represented by the following formulas (II) and (III). In Formula (II), the water contact angle after operation a is θ _{contamination} , the water contact angle after operation c is θ _heating , and the solid surface contact angle of hexadecanol is θ _HD (θ _HD = 65 °). Yes, x _{contamination} is the occupation ratio of hexadecanol on the surface of the hydrophilic film after operation a, that is, after _{contamination} with hexadecanol. In formula (III), the water contact angle after operation b is θ _{water washing} , the water contact angle after operation c is θ _heating , and the solid surface contact angle of hexadecanol is θ _HD (θ _HD = 65 °). Yes, x _{water washing} is the occupation ratio of hexadecanol after the operation b, that is, the hydrophilic film surface after water washing. The results are shown in Table 2. In Table 2, a value obtained by converting the occupation ratio into a percentage, that is, the occupation ratio (unit:%) is shown.
cos θ _{contamination} = x cos θ _HD + (1−x _{contamination} ) cos θ _heating (II)
cos θ _{water washing} = x cos θ _HD + (1−x _{water washing} ) cos θ _heating (III)

<Hydrophilicity>
The water contact angle was measured by the θ / 2 method using an automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. Specifically, each fin material was cut into 50 mm × 100 mm to prepare test plates. Subsequently, 2 μl of pure water was dropped on the hydrophilic film of each test plate, and the contact angle of water 30 seconds after the dropping was measured. This is the initial water contact angle (see Table 2). Further, the water contact angle of the surface of the hydrophilic film of the test plate after the operation b in the contamination resistance evaluation test was measured. This is the water contact angle after the contamination test (see Table 2).

As known from Tables 1 and 2, the solid surface tension polar component γ _S ^p mN / m and the solid surface tension hydrogen bonding component γ _S ^h mN / m of the hydrophilic film are 35 ≦ γ _S ^p ≦ 100, and The fin materials of Sample E1 to Sample E18 that satisfy the relationship of γ _S ^p + γ _S ^h ≧ 60 are excellent in hydrophilicity and excellent in the effect of suppressing the adsorption of higher alcohol-based contaminants.

For example the sample E1~E4 and the sample R1, from comparison with the sample R2, by the gamma _S ^p below 100 mN / m, higher alcohol contaminants hydrophilic film is not easily absorbed, it is excellent in stain resistance Is confirmed. Further, for example, by comparing the samples E12 to E14 with the samples R3 and R4, the γ _S ^{p is set} to 35 mN / m or more, and the sum of γ _S ^p and γ _S ^h is set to 60 mN / m or more, It is confirmed that the wettability of the adhesive film is improved and the hydrophilicity is excellent. A sample E3, from the comparison of the sample R5, R6, the use of silicone-based compound, gamma _S ^p becomes higher than 100, stain resistance becomes insufficient.

As described above, the surface tension polar component γ _S ^p (mN / m) and the solid surface tension hydrogen bonding component γ _S ^h (mN / m) are 35 ≦ γ _S ^p ≦ 100, γ _S ^p + γ _S ^h ≧ It can be seen that fin materials (samples E1 to E18) having a hydrophilic film satisfying the relationship of 60 have excellent hydrophilicity and can suppress adsorption of higher alcohol-based contaminants such as hexadecanol.

(Example 2)
The present example is an example of a heat exchanger provided with fins made of the fin material of the first embodiment. As shown in FIG. 4, the heat exchanger 7 is a cross fin tube type, and includes a large number of plate-like fins 8 made of the fin material 1 and a metal tube 9 for heat transfer that passes through these fins. The fins 8 are arranged in parallel at a predetermined interval. The width of the fins 8 is, for example, 25.4 mm, the height is, for example, 290 mm, the lamination pitch of the fins 8 is, for example, 1.4 mm, and the overall width of the heat exchanger 1 is, for example, 300 mm. The height direction of the fin 8 is the rolling parallel direction of the substrate. The metal pipes 7 at the width of the fins 8 are arranged in two rows, and the number of stages of the metal pipes 9 at the height of the fins 8 is 14 stages. In FIG. 5, the number of metal pipes 9 is omitted for the convenience of drawing. The metal tube 9 is a copper tube having a spiral groove on the inner surface. The dimensions of the metal tube are as follows: outer diameter: 7.0 mm, bottom wall thickness: 0.45 mm, fin height: 0.20 mm, fin apex angle: 15.0 °, helical angle: 10.0 °.

  The heat exchanger 7 was produced as follows. First, an assembly hole (not shown) having a fin collar portion having a height of 1 to 4 mm for inserting and fixing the metal tube 8 into the fin 8 made of the fin material 1 was formed by press working. After laminating the fins 8, a separately produced metal tube 7 was inserted into the assembly hole. As the metal tube 9, a copper tube was used which was subjected to grooving on the inner surface by rolling or the like, and was subjected to regular cutting and hairpin bending. Next, a tube expansion plug was inserted from one end of the metal tube 9, and the metal tube 9 was fixed to the fin 8 by expanding the outer diameter of the metal tube 9. After removing the tube expansion plug, the U vent tube was brazed to the metal tube 9 to obtain the heat exchanger 7.

  By using the samples E <b> 1 to E <b> 18 in Example 1 as the fin material 1, the heat exchanger 7 is excellent in hydrophilicity of the fins 8 and can further suppress the adsorption of higher alcohol-based contaminants. Therefore, the heat exchanger 8 can prevent the water splash phenomenon. Further, in the heat exchanger 8, since water droplets condensed between the fins 8 can be prevented from bridging, an increase in ventilation resistance can be prevented.

DESCRIPTION OF SYMBOLS 1 Fin material 2 Substrate 3 Coating film 31 Hydrophilic film 7 Heat exchanger 8 Fin

Claims (8)

A substrate made of aluminum;
A coating formed of one or two or more layers formed on the substrate, and the coating has a hydrophilic coating on the outermost surface,
The solid surface tension polar component γ _S ^p mN / m and the solid surface tension hydrogen bonding component γ _S ^h mN / m of the hydrophilic film calculated from the Fowkes expansion formula represented by the following formula (I) are 35 ≦ γ _A fin material for a heat exchanger that satisfies the relationship of _S ^p ≦ 100 and γ _S ^p + γ _S ^h ≧ 60.
γ _L (1 + cos θ _L ) = 2 (γ _s ^d × γ _L ^d ) ^1/2 +2 (γ _s ^p × γ _L ^p ) ^1/2 +2 (γ _s ^h × γ _L ^h ) ^1/2. I)
γ _L : surface tension of contact medium γ _L ^d : surface tension dispersion component of contact medium γ _L ^p : surface tension polar component of contact medium γ _L ^h : surface tension hydrogen bond component of contact medium γ _s ^d : solid surface tension dispersion Component γ _s ^p : Solid surface tension polar component γ _s ^h : Solid surface tension hydrogen bonding component   The said hydrophilic membrane | film | coat is a fin material for heat exchangers of Claim 1 whose water contact angle is 30 degrees or less.   The hydrophilic film contains at least one hydrophilic resin (A) selected from the group consisting of vinyl alcohol resins, cellulose resins, and silanol resins in a solid content mass ratio of 70% or more, and is a perfluoroalkyl. The fin material for heat exchangers according to claim 1 or 2, which contains a fluorine-based compound having a group in a solid content mass ratio of 0.6 to 5%.   The fin material for a heat exchanger according to claim 3, wherein the hydrophilic film further contains at least one kind obtained from the group consisting of polyacrylic acid, polyacrylate, and polyethylene glycol resin.   The fin material for heat exchangers according to any one of claims 1 to 4, wherein the hydrophilic film contains a crosslinking agent comprising at least one of a blocked isocyanate compound and a melamine resin.   The fin material for a heat exchanger according to any one of claims 1 to 5, wherein the hydrophilic film contains at least one of an antibacterial agent and an antifungal agent.   The coating film has a corrosion-resistant film containing at least one resin selected from the group consisting of an acrylic resin, an epoxy resin, a urethane resin, and an ester resin between the hydrophilic film and the substrate. The fin material for heat exchangers according to any one of claims 1 to 6.   The heat exchanger provided with the fin which consists of a fin material for heat exchangers of any one of Claims 1-7.

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