WO2006082905A1

WO2006082905A1 - Heat exchanger, refrigeration cycle apparatus, and hydrophilic coating for use therein

Info

Publication number: WO2006082905A1
Application number: PCT/JP2006/301796
Authority: WO
Inventors: Yasuo Itami; Makio Takeuchi; Kanji Akai; Teruo Kido; Hideo Ohya; Takayuki Hyoudou
Original assignee: Daikin Industries, Ltd.
Priority date: 2005-02-04
Filing date: 2006-02-02
Publication date: 2006-08-10
Also published as: JP2006213859A

Abstract

A heat exchanger which uses, in the evaporator thereof, a fin made of aluminum having a hydrophilic coating film formed on the surface thereof, wherein the hydrophilic coating film comprises at least one of an alkali metal salt and an ammonium salt. A heat exchanger is manufactured by using the above fin and a refrigeration cycle apparatus equipped with the above heat exchanger is manufactured.

Description

Specification

Heat exchanger, refrigeration cycle apparatus, and hydrophilic coating used for them

Technical field

The present invention relates to a heat exchanger, a refrigeration cycle apparatus, and a hydrophilic paint used for them.

Background art

[0002] Generally, heat exchange fins are subjected not only to a ground treatment for preventing corrosion of the fin base material but also to a hydrophilic treatment for preventing water droplets of condensed water generated during heat exchange. This hydrophilization treatment suppresses the formation of condensed water droplets and prevents the water droplets from scattering. In addition, since the formation of a bridge between adjacent fins due to the water droplets is suppressed, problems such as power loss and noise caused by narrowing the air ventilation path are also eliminated.

[0003] Aluminum and aluminum alloys that are excellent in lightness, workability, and thermal conductivity are often used as the fin base material. In addition, a chemical conversion treatment with chromate is used as a base treatment applied to the fin base material.

[0004] On the other hand, as a hydrophilization treatment applied to the surface of the fin substrate, for example,

(i) a method of applying a paint containing silica, water glass, aluminum hydroxide, calcium carbonate, titer, or the like, or a paint further containing a surfactant in addition to the organic resin,

(ii) a method of using a combination of polyvinyl alcohol and a specific water-soluble polymer,

(iii) a method of using a combination of a block copolymer containing a hydrophilic polymer portion and a hydrophobic polymer portion made of a specific hydrophilic monomer, and a metal chelate-type crosslinking agent,

(iv) a method using polyacrylamide-based resin

(V) a method of using a polymer such as polyacrylic acid polymer in combination with a polymer such as polyethylene oxide or polyvinylpyrrolidone that forms a polymer complex by hydrogen bonding with the polymer;

(vi) A method of applying water glass is disclosed in Patent Document 1. Among these, methods (i) to (V) are methods using an organic material as a main component, and methods (vi) are methods using an inorganic material as a main component. On the other hand, Patent Document 2 discloses a method for forming a coating film containing organic resin and silica as main components on the surface of an aluminum fin. However, according to this method, the hydrophilicity of the fin surface is sufficiently exhibited immediately after the coating film is formed, but the hydrophilicity tends to gradually decrease due to repeated drying and wetting and adhesion of hydrocarbons. is there. Patent Document 1: Japanese Patent Laid-Open No. 2002-275650

Patent Document 2: Japanese Patent Laid-Open No. 10-30069

Disclosure of the invention

[0006] In recent years, indoor heat exchangers have been used in highly-air-tight and heat-insulating buildings and in environments where chemicals such as oil, formaldehyde, and VOC (volatile organic compounds) float. The case is increasing. In this case, the chemical substance adheres to and accumulates on the hydrophilic coating film on the fin surface, whereby the hydrophilicity of the fin surface is lowered and water repellency is exhibited. As a result, the condensed water adheres to the surface of the fin and is likely to form water droplets, which may cause the water droplets to be scattered from the blowout port of the indoor unit. Similarly, when the fins are washed to remove the accumulated foreign matter, the hydrophilicity of the fin surface is reduced, and there is a possibility that water droplets are scattered from the outlet of the indoor unit. Further, in this case, the corrosion resistance of the fin base material is also lowered, and therefore, corrosion of the fins may be promoted. Currently, the mechanism for degrading the hydrophilicity of the coating film has not been elucidated, and the fact is that no permanent measures have been taken to maintain the hydrophilicity of the fins.

[0007] An object of the present invention is to eliminate the problem of a heat exchanger that uses aluminum fins in an evaporator and a refrigeration cycle apparatus that includes heat exchange, that is, water repellency on the fin surface.

[0008] As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the water repellency of the fin surface is caused by adhesion of an organic substance to the fin and two hydroxyl groups present in the hydrophilic coating film. Not only does it become ether-bonded or the hydroxyl group is converted to a carbonyl group, the hydrophilicity decreases, but it is also contained in an organic substance, or a carboxylic acid compound derived from an organic substance, aluminum and water. It was found that the main cause is aluminum carboxylate, which is a reaction product of Then, it was found that the formation of aluminum carboxylate is suppressed by containing a specific compound in the hydrophilic coating film before the reaction between the carboxylate compound and aluminum. It was.

[0009] In order to solve the above-described problems, according to the first aspect of the present invention, in heat exchange using an aluminum fin having a hydrophilic coating film on the surface for an evaporator, The coating film contains at least one of an alkali metal salt and an ammonium salt.

[0010] By configuring as described above, under the condition that the hydrophilic coating film provided on the surface of the fin comes into contact with the organic substance in the environment, the fin base force aluminum ions are eluted, and the alkali metal salt Alkali metal ions and ammonium ions are generated from at least one of ammonium salts. Components derived from organic substances react preferentially with alkali metal ions and ammonium ions over aluminum ions. Thus, before the reaction between the organic substance-derived component and the aluminum ion, the organic substance-derived component reacts with the alkali metal ion or the ammonium ion to produce a compound that is easily dissolved in water. Since the product is washed away by condensed water with heat exchange, water repellency on the fin surface is suppressed.

[0011] In the heat exchange described above, the alkali metal salt and the carboxylic acid compound A, which is a component derived from an organic substance, react to produce the alkali metal salt A1 of the carboxylic acid compound. Is preferred. In that case, the carboxylic acid compound A contained in the organic substance reacts preferentially with alkali metal ions over aluminum ions under the condition of contacting with the hydrophilic coating film on the fin surface. As a result, alkali metal carboxylate A1 is produced, while production of aluminum carboxylate is suppressed. In addition, since the alkali metal carboxylate A1 is a compound that is easily dissolved in water, it is dissolved in condensed water and easily washed away. Therefore, water repellency of the fin surface can be suppressed.

In the above heat exchanger, the alkali metal salt is preferably an alkali metal salt of a carboxylic acid compound B having a carboxyl group having a pKa of 0.3 to 15, as the alkali metal salt. A polyvalent carboxylic acid alkali metal salt such as alkali metal acetate or sodium maleate is used. In that case, the alkali metal salt of the carboxylic acid compound B includes a salt of a ruboxyl group having a strength equal to or weaker than the carboxyl group of the carboxylic acid compound A in the organic substance. Therefore, the carboxylic acid compound A deprives the alkali metal ion of the carboxylic acid compound B! Potassium metal salts are easily produced.

[0013] In the above heat exchanger, the content of the alkali metal salt is preferably 0.001 to LO weight% with respect to the hydrophilic coating film. For example, in the case of sodium maleate, the content is preferably from 0.19 to LO weight% with respect to the hydrophilic coating film. In this case, the performance as a fin can be suitably exhibited.

[0014] In the heat exchanger described above, an ammonium salt may be used instead of the alkali metal salt. In this case, although the alkali metal salt has a higher reactivity with the carboxylic acid compound A than the ammonium salt, the structure is otherwise the same. As the ammonium salt, it is preferable to use ammonium sulfate in addition to ammonium acetate and polycarboxylic acid ammonium salt. When the ammonium sulfate salt is used, the content thereof is preferably 0.15 to LO weight% with respect to the hydrophilic film.

[0015] In the above heat exchange! As a hydrophilic coating, a polyacrylic acid-based coating, a polybutyl alcohol-based coating, an epoxy-based coating, an acrylic cellulose-based coating, an acrylamide-based coating, or A coating film containing two or more types of rosin forming each coating film is used. In this case, the hydrophilicity of the fin surface can be maintained for a long time.

[0016] A second aspect of the present invention is a refrigeration cycle apparatus having the above heat exchange, and in this case as well, the same operational effects as in the case of the heat exchange can be obtained.

A third aspect of the present invention is a hydrophilic paint applied to the surface of an aluminum fin for heat exchange, and the hydrophilic paint contains at least one of an alkali metal salt and an ammonium salt. If this hydrophilic paint is used for the application of the fin surface, the function as a heat exchanger fin can be suitably exhibited, and the same effect as in the case of the heat exchanger can be obtained.

Brief Description of Drawings

FIG. 1 is a block diagram showing a schematic configuration of a refrigeration cycle apparatus of the present embodiment.

FIG. 2 is a perspective view showing the overall configuration of the heat exchanger of the present embodiment.

FIG. 3 is a partial sectional view showing a sectional structure near the surface of the fin.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the refrigeration cycle apparatus 10 includes a heat exchanger (evaporator), a compressor 12, a switching valve 13, an expansion valve 14, and a fan 15. In the refrigeration cycle apparatus 10, the surroundings are cooled through the fins of the heat exchanger ll by evaporating the refrigerant in the heat exchanger 11. The refrigeration cycle apparatus 10 is used in various refrigerators such as air conditioners, containers, and showcases.

As shown in FIG. 2, the heat exchanger 11 is a cross fin coil heat exchanger, and is configured by stacking a plurality of fins 16. A heat transfer tube 18 for circulating the refrigerant is disposed inside the heat exchanger 11. As shown in FIG. 3, the fin 16 is made of an aluminum fin base material 16a, and a hydrophilic coating film 20a is provided on the surface of the fin base material 16a.

[0020] According to the present invention, the hydrophilic coating film 20a contains at least one of an alkali metal salt and an ammonium salt. That is, the hydrophilic coating film 20a is a compound (alkali metal salt and ammonium salt) having a higher reactivity with the carboxylic acid compound A derived from an organic substance than the aluminum ion eluted from the fin base material 16a. At least one of the above. As a result, the carboxylic acid compound A derived from the organic substance reacts preferentially with alkali metal ions and ammonium ions over the aluminum ions under the condition that the organic substance contacts the surface of the fin 16. For this reason, the reaction of the carboxylic acid compound A, aluminum and water is suppressed, and the formation of aluminum carboxylate is suppressed. In this case, the preferentially produced carboxylic acid alkali metal salt A1 and carboxylic acid ammonium salt A2 are both easily soluble in water. Since these are all easily dissolved and washed away in the condensed water of the heat exchange force, the hydrophilicity of the surface of the fin 16 is not impaired as in the case where aluminum carboxylate is produced. Accordingly, water repellency on the surface of the fin 16 can be suppressed.

[0021] On the other hand, when the carboxylic acid compound C is already contained in the hydrophilic coating film 20a, at least one of an alkali metal salt and an ammonium salt may be contained in the hydrophilic coating film 20a. , Forces Alkali metal salt C1 and ammonium salt C2 of rubonic acid compound C are generated. At this time, the fin base material 16a is hardly corroded, and the elution of aluminum ions is suppressed as low as possible. Therefore, the reaction between the carboxylic acid compound C and the aluminum ion in the hydrophilic coating film 20a is suppressed. Also, in this case, condensation occurs as the heat exchanger 11 operates. Even when water is produced, at least one of the alkali metal salt CI and the ammonium salt C2 of the carboxylic acid compound C is dissolved in the condensed water and easily removed.

[0022] Under the condition that at least one of an alkali metal salt and an ammonium salt is contained in the hydrophilic coating film 20a and water is present, at least one of the alkali metal salt and the ammonium salt is dissociated. Therefore, the production of aluminum ions is suppressed.

[0023] The fin base 16a is a fin base made of aluminum or an aluminum alloy. The surface of the fin base material 16a is provided with a corrosion-resistant organic film 20b as a base treatment in order to improve the corrosion resistance. In this case, instead of the organic film 20b, chromate may be applied as a base treatment. A hydrophilic coating film 20a is formed so as to cover the organic coating film 20b. In the present embodiment, the coating film 20 is composed of the organic film 20b and the hydrophilic coating film 20a.

[0024] The hydrophilic coating film 20a contains at least one of an alkali metal salt and an ammonium salt, but otherwise has the same configuration as the hydrophilic coating film 20a conventionally applied to the fin 16. . In the present embodiment, the coating material used for forming the hydrophilic coating film 20a is defined as a hydrophilic coating material.

[0025] As a representative example of the hydrophilic coating film 20a, for example,

(1) An organic resin-based coating film in which a hydrophilic organic resin as a main component is combined with a crosslinking agent as necessary,

(2) Organic resin, which is a combination of hydrophilic organic resin and colloidal silica, which are the main components, and a crosslinking agent as required

(3) Water glass coating film that is a mixture of alkali silicate, which is the main component, and ionic or nonionic hydrophilic organic resin. Of these, from the standpoint of superior molding processability and odor resistance, organic resin-based coatings (1) and organic resin-colloidal silica-based coatings (2) are preferred. (1) is more preferable.

[0026] The hydrophilic organic resin used in the formation of the organic resin-based coating film (1) contains a hydroxyl group, a carboxyl group, an amino group, etc. in the molecule and is used as it is, or each of the functional groups is an acid. Alternatively, it is possible to use water-soluble coffee or water-dispersible resin that has been neutralized with a base. [0027] Examples of hydrophilic organic resins include polybulal alcohol, modified polybulal alcohol (for example, copolymers with acrylamide, unsaturated carboxylic acid, sulfonic acid group-containing monomer, cationic monomer, unsaturated silane monomer, etc.) ), Polyacrylic alcohols, polyacrylic acid, carboxyl group-containing acrylic resins, copolymers of ethylene and acrylic acid, acrylic resins such as ionomers, adducts of epoxy resins and amines, etc. Synthetic hydrophilic resins such as epoxy resin, acrylamide resin, polyethylene glycol, carboxyl group-containing polyester resin; natural polysaccharides such as starch, cellulose, and algin; oxidized starch, dextrin, propylene glycol alginate, carboxymethyl Starch, carboxymethylcellulose, Examples include derivatives of natural polysaccharides such as hydroxymethyl starch, hydroxymethyl cellulose, hydroxyethyl cellulose, and acrylic cellulose-based resin. Among these, acrylic resin-based resin, polybutyl alcohol-based resin, epoxy-based resin, acrylic cellulose-based resin, acrylamide-based resin, or a resin containing two or more of each of these resins is preferable. ,.

[0028] Examples of the crosslinking agent used for forming the organic resin-based coating film (1) include melamine resin, urea resin, phenol resin, polyepoxy compound, blocked polyisocyanate compound, There are metal chelate compounds. The cross-linking agent is preferably water-soluble or water-dispersible from the viewpoint of being uniformly dispersed in the coating film.

[0029] Specific examples of the cross-linking agent include, for example, methyl etherified melamine resin, butyl ether melamine resin, methylbutyl mixed etherified melamine resin, methyl ether urea resin, methyl ether benzoguanamine resin, Polyphenols or aliphatic polyvalent alcohol di- or polyglycidyl ethers, amine-modified epoxy resins, hexamethylene diisocyanate triisocyanurate blocked products: titanium (Ti), zirconium (Zr)

And metal chelate compounds of metal elements such as aluminum (A1). As the metal chelate compound, one having two or more metal alkoxide bonds in one molecule is preferable.

[0030] As the hydrophilic organic resin used in forming the organic resin 'colloidal silica-based coating film (2), the same as the hydrophilic organic resin used in forming the organic resin-coated film (1) Used organic rosin 'Colloidal silica-based coating film (2) It is so-called silica sol or finely divided silica. The particle diameter of colloidal silica is usually 5 nm to 10 μm, preferably 5 nm to 1 μm. As colloidal silica, what is supplied as a water dispersion is used as it is or in a state where finely divided silica is dispersed in water. In this case, the organic resin / colloidal silica-based coating (2) reacts in the presence of alkoxysilane with the organic resin and colloidal silica force, which may be formed by simply mixing the organic resin and colloidal silica. May be formed.

[0031] A hydrophilic organic resin used in the formation of the organic resin-based coating film (1) as the char-on or non-one hydrophilic organic resin used in the formation of the water glass-based coating film (3) Of these, eron-based or nonionic organic resins are used.

[0032] According to the present invention, at least one of the alkali metal salt and the ammonium salt contained in the hydrophilic coating film 20a has an acid group having a pKa of 0.3 to 15, for example, a carboxyl group. And at least one of an alkali metal salt and an ammonium salt of the acid, and preferably contains at least one such acid group in the molecule. By containing such an acid group as at least one of an alkali metal salt and an ammonium salt, the organic substance containing the carboxylic acid compound A can be brought into contact with the hydrophilic coating film 20a of the fin 16 under the condition that Carboxy oxide compound A is a compound (at least one of an alkali metal salt and an ammonium salt) that is more reactive than the aluminum ions eluted from the fin base material 16a, specifically, an alkali metal ion or Reacts preferentially with ammonia ions. In this case, since the reaction of the carboxylic acid compound A, aluminum, and water is suppressed, the production of aluminum carboxylate as the reaction product is suppressed. In this case, the carboxylic acid alkali metal A1 and the carboxylic acid ammonium salt A2 that react preferentially are compounds that are easily dissolved in water. Dissolved in water and easily washed away. Therefore, the hydrophilicity of the surface of the fin 16 is not impaired as in the case where aluminum carbonate is produced. That is, water repellency on the surface of the fin 16 is suppressed.

[0033] At least one of the alkali metal salt and the ammonium salt preferably contains an acid group having a pKa of 4.5 to 13. In this case, as the acid group, for example, at least one of an alkali metal salt and an ammonium salt of a carboxylic acid compound B containing a carboxyl group, an alkali metal salt such as sulfuric acid, phosphoric acid, polyphosphoric acid, boric acid, and the like, and List at least one of the ammonium salts It is done. Among these, alkali metal salts of monocarboxylic acids such as sodium formate and sodium acetate, alkali metal salts of polyvalent monocarboxylic acids such as sodium maleate (at least one of monosodium maleate and disodium maleate) and sodium glutamate Ammonium salts of the above monocarboxylic acids and polyvalent monocarboxylic acids, ammonium sulfate, and the like are preferable.

[0034] Examples of the carboxylic acid compound B include a carboxylic acid compound having a carbon number other than carbon contained in the carboxyl group and having 10 to 10 carbon atoms, specifically, formic acid, acetic acid, maleic acid. An acid, glutamic acid, etc. are mentioned.

[0035] The hydrophilic coating film 20a of the present invention may be formed from the coating film component and at least one of an alkali metal salt and an ammonium salt. In order to improve the hydrophilicity of the coating film 20, If necessary, a surfactant may be contained. As the surfactant, hydrophilic polymer fine particles are used, and the average particle diameter thereof is 0.03 to 1 μm, preferably 0.05 to 0.6 μm. The hydrophilic coating 20a is composed of antibacterial agents such as 2- (4-thiazolyl) benzimidazole, bis (dimethylthiolrubamoyl) disulfide, zeolite (aluminosilicate), tannic acid, phytic acid, benzotriazole, etc. It may contain an antifungal agent, oxyacid salt compounds such as molybdenum, vanadium, zinc, nickel, cobalt, copper, iron, and pigments such as colored pigments, extender pigments, and antifungal pigments.

[0036] The content of at least one of the alkali metal salt and the ammonium salt is set to 0.01% by weight or more with respect to the hydrophilic coating film 20a. In the case of an alkali metal salt, the content is preferably at least 0.19% by weight, more preferably at least 0.38% by weight, more preferably at least 1% by weight, and even more preferably at least 2% by weight. . On the other hand, the content of ammonium salt is preferably 0.15% by weight or more, more preferably 0.3% by weight or more, more preferably 1% by weight or more, and even more preferably 2% by weight or more. Is more preferable. If the content is set in this manner, the effect of the present invention can be maintained for a long time by sufficiently reacting with the carboxylic acid compound A derived from an organic substance adhering to substantially the entire surface of the fin 16. In addition, the content of at least one of the alkali metal salt and the ammonia salt is sufficient to maintain the hydrophilicity of the hydrophilic coating film 20a for a long period of time, or in the hydrophilic coating film 20a. 10% by weight or less is preferable, and 6% by weight or less is more preferable 5% from the viewpoint of uniformly dispersing the salt. % Or less is more preferred 4% by weight or less is even more preferred.

[0037] The paint used for forming the hydrophilic coating film 20a may already contain at least one of an alkali metal salt and an ammonium salt. In this case, a combination of at least one of alkali metal salt and ammonium salt in the paint and at least one of alkali metal salt and ammonium salt added later is included in the hydrophilic coating film 20a of the present invention. It is defined as at least one of alkali metal salt and ammonium salt.

[0038] Further, the coating material is defined as the hydrophilic coating material of the present invention, and the proportions of various components contained in the hydrophilic coating material are the same as those of the hydrophilic coating film described above. That is, there is a difference between the state of the hydrophilic coating film 20a formed on the surface of the fin 16 or the state of the paint before forming the hydrophilic coating film 20a.

Next, the fin 16 and the manufacturing method thereof will be described.

The fin 16 is formed by providing an organic film 20b on the surface of the fin base material 16a and providing a hydrophilic coating film 20a on the film 20b. As the fin base 16a, any conventionally known aluminum fin base is used.

[0040] First, the organic film 20b is formed so as to cover the surface of the fin base material 16a. In this case, the organic coating film 20b is formed by applying a paint to the surface of the fin base 16a and drying the paint. Examples of the method of forming the organic film 20b include coating methods such as immersion coating, shower coating, spray coating, roll coating, and electrodeposition coating. The coating material is applied to the fin base material 16a in a state force assembled in the heat exchanger 11 or in a state before being assembled. After application, the fin base material 16a is dried. At this time, the drying temperature is set to 60 to 250 ° C, and the drying time is set to 2 seconds to 30 minutes.

[0041] The thickness of the organic film 20b is usually 0.001 to 10 μm, and preferably 0.1 to 3 μm. If the thickness of the organic film 20b is less than 0.001 / zm, the corrosion resistance and water resistance of the fin base material 16a may not be sufficiently obtained. On the other hand, when the thickness of the organic film 20b exceeds 10 m, the organic film 20b is liable to be cracked, and there is a possibility that sufficient hydrophilicity cannot be obtained.

[0042] Next, the organic film 20b is formed so as to cover the surface of the organic film 20b. In this case, the hydrophilic coating film 20a is formed by applying a hydrophilic coating to the surface of the organic coating 20b and drying the coating. Examples of the method for forming the hydrophilic coating film 20a include dip coating and shading. Methods such as single coating, spray coating, roll coating, and electrodeposition coating are used. Hydrophilic coating

The thickness of 20a is usually 0.3 to 5 μm, preferably 0.5 to 3 μm, and is not particularly limited to these set values. The drying conditions of the hydrophilic coating film 20a are set according to the type of organic resin, the thickness of the coating film, etc., but preferably the drying temperature is set to about 80 to 250 ° C and the drying time is set. Is set to about 5 seconds to about 30 minutes. Through the above-described steps, the heat exchange aluminum fin 16 is manufactured.

According to the present embodiment, the following effects can be obtained.

(1) The hydrophilic coating film 20a contains at least one of an alkali metal salt and an ammonium salt. Thus, even when the organic substance comes into contact with the fins 16, the carboxylic acid compound A derived from the organic substance preferentially reacts with at least one of alkali metal ions and ammonium ions. Then, at least one of an alkali metal salt A1 and an ammonium salt A2 of the carboxylic acid compound A is produced. Since these products are all easily dissolved in water, they are easily washed away by the condensed water from the heat exchanger 11. Therefore, the hydrophilicity of the hydrophilic coating film 20a is maintained, so that the water repellency of the surface of the fin 16 is suppressed. Further, at least one of the alkali metal salt and the ammonium salt in the hydrophilic coating 20a is appropriately changed in the content or type thereof, thereby allowing the alkali metal salt or ammonium salt of the carboxylic acid to be changed. Etc., and the solubility of these products in water can be improved. Further, the acid forming at least one of the alkali metal salt and the ammonium salt preferably has a pKa in a predetermined range. In addition, the water repellency of the surface of the fin 16 can be further suppressed by appropriately changing the type of the hydrophilic coating film 20a. The same effect can be obtained in the heat exchange 11 using the fins 16 in the evaporator. The same effect can be obtained in the refrigeration cycle apparatus 10 including the heat exchanger 11. Further, when the fins 16 are formed using the hydrophilic paint and the heat exchange 11 is manufactured using the fins 16, the same effects can be obtained.

[0044] According to the present invention, since the water repellency of the surface of the fin 16 is suppressed, it is possible to prevent splashing of water droplets formed on the surface of the fin 16 or between adjacent fins 16, and air conditioning. It is also possible to improve the ventilation performance of the system. The present invention is particularly applicable to uses such as heat exchangers, air conditioners, and refrigerators for indoor air conditioners. Example

Next, the embodiment will be described more specifically with reference to examples and comparative examples.

[Example 1 and Conventional Example 1]

The film thickness of the coated film after drying is applied to the surface of the chromate-treated aluminum fin substrate.

The paints listed in Table 1 were applied so that the thickness was 0.5 m. The paint was dried at 200-220 ° C for 30 seconds to prepare two types of coated products. Fins were formed from these paints, and heat exchangers were made using them. At that time, the fins coated with the paint of Example 1 were used for half of the bundle of fins constituting the heat exchanger, and the fins coated with the paint of Conventional Example 1 were used for the other half. The heat exchanger is installed in a multi-flow cassette type air conditioner, and the air conditioner is installed on the ceiling of the office. The air conditioner is operated for 10 hours per day for three power months from July to September. Carried out. Three months after the start of the evaluation test, the front panel of the air conditioner was removed and the fins were observed. As a result, in the fin coated with the paint of Example 1, formation of bridges due to water droplets, scattering of water droplets, and the like were confirmed. On the other hand, in the fin coated with the paint of Conventional Example 1, the formation of bridges due to water droplets and the scattering of water droplets were confirmed.

[0046] According to this evaluation test, the hydrophilicity of the fin surface was kept good in the case of Example 1, but the hydrophilicity of the fin surface was lowered in the case of Conventional Example 1.

[0047] [Table 1]

* 1: Polyvinyl alcohol paint,

Claims

The scope of the claims

[I] In a heat exchanger that uses aluminum fins with a hydrophilic coating on the surface for the evaporator,

The heat exchange film characterized in that the hydrophilic coating film contains at least one of an alkali metal salt and an ammonium salt.

[2] The heat exchanger according to claim 1, wherein the alkali metal salt is an alkali metal salt of a carboxylic acid compound having a carboxyl group having a pKa of 0.3 to 15.

[3] The heat exchanger according to claim 1 or 2, wherein the alkali metal salt is an alkali metal acetate or an alkali metal polyvalent carboxylic acid.

[4] The heat exchanger according to any one of claims 1 to 3, wherein the content of the alkali metal salt is 0.01 to 10 wt% with respect to the hydrophilic coating film. ^.

[5] The alkali metal salt is sodium maleate, and the content of sodium maleate is

The heat exchanger according to any one of claims 1 to 4, wherein the content is 0.19 to 10% by weight based on the hydrophilic coating film.

6. The heat exchanger according to claim 1, wherein the ammonium salt is an ammonium salt of a carboxylic acid compound having a carboxyl group having a pKa of 0.3 to 15.

[7] The ammonium salt is an ammonium sulfate salt, an ammonium acetate salt, or an ammonium salt of a polyvalent carboxylic acid. Heat exchange ^^.

[8] The content of the ammonium salt is 0.01 to 10% by weight with respect to the hydrophilic coating film. Heat exchanger.

[9] The heat exchanger according to claim 7 or 8, wherein the content of the ammonium sulfate salt is 0.15 to 10% by weight with respect to the hydrophilic coating film.

[10] The hydrophilic coating is an acrylic acid-based coating, a polyvinyl alcohol-based coating, an epoxy-based coating, an acrylic cellulose-based coating, an acrylamide-based coating, or a resin that forms each of the coatings. The heat exchanger according to any one of claims 1 to 9, wherein the heat exchanger is a coating film containing two or more of the following.

[II] A refrigeration cycle apparatus comprising the heat exchange according to any one of claims 1 to 10.

[12] A hydrophilic paint applied to the surface of the heat exchanger aluminum fin, wherein the hydrophilic paint contains at least one of an alkali metal salt and an ammonium salt. paint.

[13] The hydrophilic paint according to claim 12, wherein the alkali metal salt is an alkali metal salt of a carboxylic acid compound B having a carboxyl group having a pKa of 0.3 to 15.

14. The hydrophilic paint according to claim 12 or 13, wherein the alkali metal salt is an alkali metal acetate or an alkali metal salt of a polyvalent carboxylic acid.

[15] The hydrophilic paint according to any one of claims 12 to 14, wherein the content of the alkali metal salt is 0.01 to L0% by weight with respect to the hydrophilic paint. .

[16] The alkali metal salt is sodium maleate, and the content of sodium maleate is

The content is 0.19 to 10% by weight based on the hydrophilic paint.

5. The hydrophilic paint according to item 1 above.

17. The hydrophilic paint according to claim 12, wherein the ammonia salt is an ammonium salt of a carboxylic acid compound having a carboxyl group having a pKa of 0.3 to 15.

[18] The hydrophilic property according to claim 12 or 17, wherein the ammonium salt is an ammonium sulfate salt, an ammonium acetate salt or an ammonium salt of a polyvalent carboxylic acid. paint.

[19] The content of the ammonium salt is 0.01 to L0% by weight with respect to the hydrophilic paint. Hydrophilic paint.

20. The hydrophilic paint according to claim 18 or 19, wherein the content of the ammonium sulfate salt is 0.15 to 10% by weight with respect to the hydrophilic paint.

[21] The hydrophilic paint includes two or more of acrylic acid paint, polyvinyl alcohol paint, epoxy paint, acrylic cellulose paint, acrylamide paint, or a resin forming each paint. The hydrophilic paint according to any one of claims 12 to 20, wherein the hydrophilic paint is a paint.