JP2006214675A - Heat exchanger, refrigeration cycle apparatus and hydrophilic paint used for them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of dust and trash adhered to a surface of a fin of a refrigerating cycle device having a heat exchanger using the fin for the surface hydrophilic heat exchanger in an evaporator. <P>SOLUTION: This heat exchanger uses the fin for the heat exchanger provided with a hydrophilic film on the surface of the fin in the evaporator. The hydrophilic film contains a functional group-switching agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a heat exchanger in which a hydrophilic coating film is provided on the surface of a fin for a heat exchanger, the heat exchanger containing a functional group switching agent in the hydrophilic coating film, and evaporating the heat exchanger The present invention relates to a refrigeration cycle apparatus used in a vessel and a hydrophilic paint used to form the hydrophilic coating film.

  The fins for indoor heat exchangers used in indoor heat exchangers are subjected to a ground treatment to prevent corrosion of the fin base material, and then the condensed water generated during cooling becomes water droplets. Surface hydrophilization treatment is performed to prevent deterioration of the performance. If the condensed water is in the form of water droplets, it may cause problems such as splashing of water droplets, and if the water droplets form a bridge, the air flow path is narrowed to increase airflow resistance, resulting in power loss, noise generation, etc. Problems arise.

  As the fin base material, a base material made of aluminum or aluminum alloy having excellent lightness, workability, and thermal conductivity is generally used. Further, as a base treatment for preventing corrosion of the fin base material, a chemical conversion treatment with chromate is generally performed.

On the other hand, as the surface hydrophilization treatment, for example, (i) a paint in which silica, water glass, aluminum hydroxide, calcium carbonate, titania or the like is mixed with an organic resin, or a paint further containing a surfactant in these paints is used. A method of coating (ii) a method of using a combination of polyvinyl alcohol and a specific water-soluble polymer (iii) a block copolymer consisting of a hydrophilic polymer portion comprising a specific hydrophilic monomer and a hydrophobic polymer portion; (Iv) a method using a metal chelate type crosslinking agent in combination (iv) a method using a polyacrylamide resin (v) a polymer such as a polyacrylic acid polymer, and a polyethylene oxide capable of forming a polymer complex by hydrogen bonding with this polymer Use organic materials as the main component, such as a method using in combination with polymers such as polyvinylpyrrolidone And methods,
(Vi) A method of using an inorganic material as a main component such as a method of applying water glass is disclosed (for example, see Patent Document 1).
JP 2002-275650 A (see, for example, paragraphs [0002] to [0007])

  The fin provided with a hydrophilic coating film on the surface of the fin for the heat exchanger can improve the trouble caused by the condensed water generated during cooling in the form of water droplets and further the water droplets forming bridges. Because the coating is provided, the surface is hydrophilic even during shutdown, and dust and debris that have an affinity for it are easily attached. Since this dust and debris has affinity for the hydrophilic surface, the subsequent cooling There is a problem that it is difficult to remove even with condensed water generated by resuming operation. However, the fact is that there is no effective method for solving such problems.

  The present invention is a problem of the refrigeration cycle apparatus using the heat exchanger fin provided with the hydrophilic coating film, that is, since the hydrophilic coating film is provided, the surface exhibits hydrophilicity even during shutdown. The object is to solve the problem that dust and dirt having an affinity are easily attached and difficult to remove.

  As a result of intensive studies to solve the above problems, the present inventors have made the surface hydrophilic even during the operation stop, so that it is difficult to remove dust / dust having affinity for the hydrophilic coating film. The problem is that if a coating film that becomes hydrophilic during operation and becomes water-repellent during operation stoppage can be developed, the above problem can be solved while achieving the purpose of providing a hydrophilic coating film. I reached the idea that I could do it. In addition, the present inventors have conducted various studies on a method for forming a hydrophilic coating film having different characteristics during operation and during operation stop as described above. As a result, functional switching has been performed on the hydrophilic coating film. The inventors have found that the purpose can be achieved by containing an agent, and have completed the present invention.

  The present invention relates to a heat exchanger in which a fin for a heat exchanger provided with a hydrophilic coating film on a fin surface is used for an evaporator, wherein the hydrophilic coating film contains a functional group switching agent. is there.

  In the present invention, when the heat exchanger is operated as an evaporator (when cooling operation is performed), the hydrophilic coating film is wetted by the generated condensed water, and the contained functional group switching agent The surface also becomes hydrophilic and does not impair the properties of the hydrophilic coating film. On the other hand, when the operation of the heat exchanger as an evaporator is stopped, the supply of condensed water is stopped, so that the hydrophilic coating film in a wet state is dried. When the hydrophilic coating film is dried, the surface of the functional group switching agent contained in the coating film exhibits water repellency, and the coating film surface also exhibits water repellency. As a result, the dust / dust attached to the surface of the coating film during operation stop adheres to the dust / dust having affinity with the surface of the water-repellent coating film. Condensed water is generated by restarting the cooling operation, the surface of the functional group switching agent becomes hydrophilic, and the surface of the coating film becomes hydrophilic. As a result, dust and dirt having an affinity for the surface of the water-repellent paint film that adheres to the surface of the paint film are easily washed away with condensed water, and the amount of dust and dirt on the surface of the hydrophilic paint film is considered to be reduced. It is done.

  The functional group switching agent has both a hydrophilic functional group and a water repellent functional group. When the surrounding environment is in a wet state, the hydrophilic functional group is compatible with the surrounding environment. It is hydrophilic so that the group comes out on the surface and is better compatible with the surrounding environment. If the surrounding environment is not moist (when it shows water repellency in the dry state), it should be compatible with the surrounding environment. A material that exhibits water repellency so that the water-repellent functional group is exposed to the surface and is compatible with the surrounding environment, for example, a material whose surface performance can be changed to hydrophilic and water repellency in the presence or absence of water. That is. Preferable specific examples include silicone polymer materials.

  As the functional group switching agent, when a material whose surface performance can be changed to hydrophilicity and water repellency in the presence or absence of water, preferably a silicone polymer material, a hydrophilic coating is provided on the fin surface. The effect obtained when the operation / stop of the heat exchanger of the present invention using the heat exchanger fins in the evaporator is repeated can be made more remarkable.

  Further, in the present invention, the hydrophilic coating film is a polyacrylic acid coating film, a polyvinyl alcohol coating film, an epoxy coating film, an acrylic cellulose coating film, an acrylamide coating film, or a resin that forms the coating film. It can be set as the coating film containing any 2 or more types of resin.

  When the coating film is used, the hydrophilic coating film provided on the surface of the heat exchanger fin is likely to change into a hydrophilic performance surface or a water-repellent performance surface in the presence or absence of water. The fin surface of the heat exchanger also shows hydrophilicity when the fin surface is wet, such as during cooling operation, and exhibits water repellency when the fin surface being stopped is dry.

Although the above description is about the heat exchanger, the same effect is applied to the refrigeration cycle apparatus using the heat exchanger.
Moreover, when the hydrophilic coating material which can form the coating film formed on the surface of the said fin for heat exchangers is used for the coating of the surface of the fin for heat exchangers, the fin used for the heat exchanger of this invention Is obtained and acts in the same manner as the heat exchanger of the present invention.

  By including a functional group switching agent in the hydrophilic coating film on the fin of the heat exchanger of the present invention, condensed water is generated during the heat exchanger operation, and the fin surface becomes wet. The agent exhibits hydrophilicity, and the coating film is made hydrophilic. On the other hand, when the heat exchanger is stopped, since the condensed water is not supplied, the coating film is dried. At this time, since the functional group switching agent exhibits water repellency as the coating film dries, the surface of the coating film also becomes water repellant. As a result, dust and dirt attached to the fin surface while the heat exchanger is stopped have affinity for the water-repellent surface, and the condensed water generated by restarting the cooling operation makes the surface hydrophilic and functional group switching. The surface of the agent also becomes hydrophilic, and dust and dirt having an affinity for the attached water-repellent surface are easily washed away. By defining the type of the functional group switching agent and the type of the hydrophilic coating film, the effect of the present invention can be improved. Moreover, the same effect is acquired also in the refrigerating-cycle apparatus which uses this heat exchanger. Furthermore, the heat exchanger fin of the present invention is obtained by manufacturing a heat exchanger fin using a hydrophilic paint and then manufacturing the heat exchanger, and the heat exchanger is obtained by using the heat exchanger. The effect when used is obtained.

The best mode for carrying out the present invention will be described below.
The heat exchanger of the present invention is a heat exchanger in which a fin for a heat exchanger provided with a hydrophilic coating film on a fin surface is used for an evaporator, and a functional group switching agent is contained in the hydrophilic coating film. Yes.

  The heat exchanger fins provided with a hydrophilic coating on the surface are treated for improving the corrosion resistance, for example, the chromate treatment, the formation of the corrosion resistant coating or the chromate treatment and the corrosion resistance on the fin base surface made of aluminum or aluminum alloy, for example. A fin provided with a hydrophilic coating film on the surface is provided with a hydrophilic coating film on the surface of the fin.

The said hydrophilic coating film is the same as the hydrophilic coating film conventionally provided in the fin for heat exchangers, except that the functional group switching agent is contained in the hydrophilic coating film.
As typical examples of the hydrophilic coating film, for example, (1) an organic resin coating film comprising a hydrophilic organic resin as a main component and a combination of a crosslinking agent as required,
(2) An organic resin / colloidal silica-based coating film comprising a hydrophilic organic resin and colloidal silica as main components, and a combination of a crosslinking agent as required;
(3) A water glass coating film that is a mixture of an alkali silicate as a main component and an anionic or nonionic hydrophilic organic resin can be used. Of these, the organic resin-based coating film (1) and the organic resin / colloidal silica-based coating film (2) are preferable from the viewpoint of molding processability and odor resistance, and the organic resin-based coating film (1) is more preferable.

  The hydrophilic organic resin used for forming the organic resin-based coating film (1) contains a functional group such as a hydroxyl group, a carboxyl group or an amino group in the molecule, or the functional group is an acid or a base as it is. Examples of the resin that can be water-soluble or water-dispersible by neutralization with the above.

  Specific examples of the hydrophilic organic resin include, for example, polyvinyl alcohol, modified polyvinyl alcohol (eg, a copolymer with acrylamide, unsaturated carboxylic acid, sulfonic acid group-containing monomer, cationic monomer, unsaturated silane monomer, etc.). Polyvinyl alcohol resin, polyacrylic acid, carboxyl group-containing acrylic resin, acrylic resin such as copolymer ionomer of ethylene and acrylic acid, epoxy resin such as adduct of epoxy resin and amine, acrylamide resin, Synthetic hydrophilic resins such as polyethylene glycol and carboxyl group-containing polyester resins; natural polysaccharides such as starch, cellulose, and algin; oxidized starch, dextrin, propylene glycol alginate, carboxymethyl starch, carboxymethylcellulose Hydroxymethyl starch, hydroxymethyl cellulose, hydroxyethyl cellulose, and the like can be given natural polysaccharide derivatives such as acrylic cellulose resin. Among these, for example, an acrylic acid resin, a polyvinyl alcohol resin, an epoxy resin, an acrylic cellulose resin, an acrylamide resin, or a resin containing two or more of the above resins is hydrophilic and water resistant. From the viewpoint of compatibility and cost, a mixture of a polyacrylic acid resin and a polyvinyl alcohol resin is more preferable.

  Examples of the crosslinking agent used as necessary in the organic resin coating film (1) include melamine resin, urea resin, phenol resin, polyepoxy compound, blocked polyisocyanate compound, metal chelate compound and the like. it can. In general, the crosslinking agent is preferably water-soluble or water-dispersible from the viewpoint that a uniform coating film is easily formed.

  Specific examples of the crosslinking agent include, for example, a methyl etherified melamine resin, a butyl etherified melamine resin, a methylbutyl mixed etherified melamine resin, a methyl etherified urea resin, a methyl etherified benzoguanamine resin, a polyphenol or a dihydric polyhydric alcohol. -Or polyglycidyl ether, amine-modified epoxy resin, hexamethylene diisocyanate triisocyanurate block product; metal chelate compounds of metal elements such as titanium (Ti), zirconium (Zr), aluminum (Al), etc. it can. The metal chelate compound preferably has two or more metal alkoxide bonds in one molecule.

  As the hydrophilic organic resin used for forming the organic resin / colloidal silica-based coating film (2), the same hydrophilic organic resin used for forming the organic resin-based coating film (1) may be used. it can.

  The colloidal silica used for forming the organic resin / colloidal silica-based coating film (2) is so-called silica sol or finely divided silica, and the particle diameter is usually about 5 nm to 10 μm, preferably 5 nm to 1 μm. Usually, what is supplied as an aqueous dispersion can be used as it is, or finely divided silica can be dispersed in water. When forming the organic resin / colloidal silica-based coating film (2), the organic resin and colloidal silica may be simply mixed, or the organic resin and colloidal silica are reacted in the presence of alkoxysilane to form a composite. It may be made.

  As the anionic or nonionic hydrophilic organic resin used for forming the water glass-based coating film (3), among the hydrophilic organic resins used for forming the organic resin-based coating film (1), anionic Alternatively, a nonionic organic resin can be used.

  In the present invention, the functional group switching agent contained in the hydrophilic coating film is such that when the coating film surface is covered with water or the like, a hydrophilic part having a siloxane bond or a hydroxyl group is oriented on the surface. It is characterized by the property that hydrophobic groups such as methyl groups are inverted and exist inside, and conversely, when water on the surface of the coating disappears, hydrophobic groups such as methyl groups are oriented on the surface. It is.

  Examples of the functional group switching agent include, for example, dimethyl silicone, methylphenyl silicone, methyl hydrogen silicone, and the like, which are silicone polymer materials.

  The functional group switching agent may be a liquid type or a solid type such as a fine powder type, but the liquid type is a material used for forming the hydrophilic coating film. Mixing is easy and functional group switching properties in a dry state and a wet state are likely to occur even after the coating film is formed.

Moreover, the said functional group switching agent can also be used as an emulsification and dispersion, and can also be used after mixing with resin which forms a hydrophilic coating film.
The amount of the functional group switching agent contained in the hydrophilic coating film is 0.05% by weight or more, further 0.35% by weight or more in terms of solid content with respect to the hydrophilic coating film containing the functional group switching agent. It is preferable from the viewpoint that it can be uniformly dispersed and oriented on the surface of the coating film and can exhibit performance, and it is 10% by weight or less, more preferably 4% by weight or less, and the coating film is easily formed This is preferable because the performance can be maintained for a longer period. For example, when a dimethyl silicone compound is used as the functional group switching agent, it is preferably 0.06% by weight or more, more preferably 0.13% by weight or more, and preferably 10% by weight or less, It is preferably 1.5% by weight or less.

  The paint used for forming the paint is the hydrophilic paint of the present invention, and the use ratio of each component is the same as in the case of the coating film. The difference is whether the form has already been formed on the coating film or the state of the paint before the coating film is formed.

  Next, a heat exchanger fin used in the present invention, for example, an aluminum fin for a heat exchanger and a manufacturing method thereof will be described. The heat exchanger of the present invention is a heat exchanger having the heat exchanger fins, and the refrigeration cycle apparatus of the present invention is a refrigeration cycle measure having the heat exchanger.

  The heat exchanger aluminum fin, which is a representative example of the heat exchanger fin used in the present invention, is formed on a surface of a fin base made of aluminum or aluminum alloy with a film for improving corrosion resistance, and the hydrophilic coating film is formed on the surface of the fin base. It is provided.

As the aluminum fin base material, those known per se that can be conventionally used as the aluminum fin base material for heat exchangers can be used.
By providing a film for improving the corrosion resistance on the aluminum fin base material, an aluminum fin base material having a corrosion resistance improving film can be obtained. The coating is an aluminum fin base (which may be assembled in a heat exchanger), a processing method known per se, such as dip coating, shower coating, spray coating, roll coating, electrodeposition coating, etc. It can be carried out by the coating method. The drying condition when the film is coated is usually performed by drying for about 2 seconds to about 30 minutes under the condition that the maximum temperature reached by the base material is about 60 to 250 ° C.

  Moreover, as a dry film thickness, the range of 0.001-10 micrometers normally, especially 0.1-3 micrometers is preferable. When the thickness is less than 0.001 μm, the performance such as corrosion resistance and water resistance tends to be inferior. On the other hand, when the thickness exceeds 10 μm, the formed film tends to be broken or the hydrophilicity tends to be inferior.

  A hydrophilic paint containing the functional group switching agent is applied to an aluminum fin base material (which may be assembled in a heat exchanger) provided with the coating, and a coating method known per se, for example, dip coating By applying and drying by a method such as shower coating, spray coating, roll coating, electrodeposition coating, etc., an aluminum fin for a heat exchanger having a hydrophilic coating film formed on the surface can be produced. Although there is no limitation in particular in the film thickness of the said hydrophilic coating film, it is 0.3-5 micrometers normally, Preferably it exists in the range of 0.5-3 micrometers. Moreover, the formation conditions (drying conditions) of the hydrophilic coating film can be appropriately set according to the type of organic resin used, the thickness of the coating film, and the like. Usually, the maximum temperature reached by the aluminum fin material is about 80 to 250. It is preferable to dry at about 5 seconds for about 5 seconds to about 30 minutes.

The heat exchanger fin having a hydrophilic coating film formed on the surface thus manufactured is used for an evaporator of the heat exchanger, and the manufactured heat exchanger is used for manufacturing a refrigeration cycle apparatus. .
The refrigeration cycle apparatus refers to an air conditioner and a refrigerator, for example, a container refrigerator, a commercial refrigerator, a refrigerator such as a showcase, and a refrigerator for a refrigeration facility. The device that cools the surroundings.

Next, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.
[Example 1 and Conventional Example 1]
Two types of coatings were applied on the aluminum fin base material whose surface was chromated and the coating materials listed in Table 1 were applied so that the dry film thickness was 0.5 μm and dried at 200 to 220 ° C. for 30 seconds. I got a thing. Aluminum fins were produced from the obtained coated material, and the obtained aluminum fins were used to make aluminum fins coated with the paint of Example 1 half of the number of aluminum fin bundles forming the heat exchanger, and the rest One half of the heat exchanger was made of aluminum fins coated with the paint of Conventional Example 1, and then a ceiling-embedded multiflow cassette type air conditioner was produced.

  The obtained air conditioner was installed in a general office and operated for 10 hours / day for three months from July to September. After 3 months, the aluminum fins were removed from the air conditioner and divided into a part coated with the paint of Example 1 and a part painted with the paint of Conventional Example 1, and each part (width 12 mm, length 200 mm, 30 sheets) The bundle was washed with ultrasonic water. Thereafter, the washing water was filtered and the filter paper was observed. In the case where the paint of Example 1 was applied but the wash water was filtered, the filter paper was white and free of dirt, but the paint of Conventional Example 1 was applied. When the washing water was filtered, the filter paper was dark.

＊１：ポリビニルアルコール系塗料。 From the above results, it can be seen that the aluminum fin used in the present invention has a hydrophilic coating film that is easily removed even if dust or dirt is attached during operation stop.

* 1: Polyvinyl alcohol paint.

  The fin for heat exchangers using the hydrophilic paint of the present invention is provided with a hydrophilic coating film containing a functional group switching agent on the surface, so that it becomes water repellent during shutdown and has an affinity for the hydrophilic surface. It is difficult to attach dust and dirt with water and has an affinity for water-repellent surfaces, so it is easy to be washed away by condensed water generated by cooling operation, and less dust and dirt adhere to the hydrophilic coating film. can do. Therefore, it can be suitably used for various refrigeration cycle apparatus applications such as a heat exchanger using the fins, an air conditioner using the heat exchanger, a refrigerator, and a refrigeration apparatus for refrigeration equipment.

Claims (9)

  A heat exchanger using a fin for a heat exchanger having a hydrophilic coating film on a fin surface as an evaporator, wherein the hydrophilic coating film contains a functional group switching agent. .   The heat exchanger according to claim 1, wherein the functional group switching agent is a material whose surface performance can be changed to hydrophilicity and water repellency in the presence or absence of water.   The heat exchanger according to claim 1 or 2, wherein the functional group switching agent is a silicone polymer material.   The hydrophilic coating film is a polyacrylic acid coating film, a polyvinyl alcohol coating film, an epoxy coating film, an acrylic cellulose coating film, an acrylamide coating film, or a resin that forms these coating films. It is a coating film containing the above resin, The heat exchanger of any one of Claims 1-3 characterized by the above-mentioned.   A refrigeration cycle apparatus using the heat exchanger according to any one of claims 1 to 4.   A hydrophilic paint to be coated on a fin surface, wherein the hydrophilic paint contains a functional group switching agent.   7. The hydrophilic paint according to claim 6, wherein the functional group switching agent is a material whose surface performance can be changed to hydrophilicity and water repellency in the presence or absence of water.   The hydrophilic paint according to claim 6 or 7, wherein the functional group switching agent is a silicone polymer material.   The hydrophilic paint is a paint containing any two or more of polyacrylic acid paints, polyvinyl alcohol paints, epoxy paints, acrylic cellulose paints, acrylamide paints and resins forming these paints. The hydrophilic paint according to claim 6, wherein the hydrophilic paint is present.