JP2014142139A - Heat exchanger aluminum fin material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger aluminum fin material excellent in hydrophilic persistence and exhibiting high adhesiveness even in a wet environment.SOLUTION: A heat exchanger aluminum fin material includes: a substrate 2; a surface treatment layer 3 including at least one layer out of a corrosion resistance coating film 3a and a hydrophobic coating layer 3b; and a hydrophilic treatment layer 4 formed on a surface of the surface treatment layer 3, and including a film layer that contains a mixture of predetermined silica-based porous fine particles 4a, carboxyl group-based high polymers 4b, and hydroxyl group-based high polymers 4a. An adhesion amount of the silica-based porous fine particles 4a is a predetermined amount, a solid content weight rate of the silica-based porous fine particles 4a is equal to or greater than 0.05 and less than 1.0 of a total solid content weight of the carboxyl group-based high polymers 4b and the hydroxyl group-based high polymers 4b, and a solid content weight rate of the carboxyl group-based high polymers 4b is 0.1 to 10.0 of a solid content weight of the hydroxyl group-based high polymers 4b.

Description

  The present invention relates to a fin material for a heat exchanger, and more particularly to an aluminum fin material for a heat exchanger provided with a substrate made of aluminum or an aluminum alloy.

Heat exchangers are used in products in various fields such as room air conditioners, packaged air conditioners, refrigeration showcases, refrigerators, oil coolers, and radiators.
When this heat exchanger is driven (during condensing operation), water vapor generated in the liquefaction is adhered to the fin surface of the heat exchanger by liquefying (condensing) water vapor in the air. As a result, water droplet bridges are formed between the fins, and depending on the usage environment, frost is formed and clogging occurs between the fins, resulting in an increase in ventilation resistance and the heat exchange rate of the heat exchanger. (Heat exchange efficiency) is reduced.

  In order to prevent the heat exchange efficiency of the heat exchanger from being reduced due to such water droplets and frost, a method of improving the hydrophilicity of the fins is performed in order to cause the water droplets on the fin surface to flow down as a water film. ing.

  As a method of improving the hydrophilicity of the fin, after providing various undercoat layers on the surface of the fin material, an inorganic hydrophilic film mainly composed of silicic acid or silicate such as water glass or colloidal silica is applied and baked. A method of forming a resin-based hydrophilic film using a hydrophilic resin such as polyethylene glycol or the like, and a method of forming by baking are widely used (for example, see Patent Documents 1 to 3).

However, in the method as described above, since the surface of the fin material is insufficiently roughened, the hydrophilicity is not maintained, and is insufficient in terms of defrosting and anti-refrosting properties. There was a problem.
As a technique for solving this problem, Patent Document 4 discloses the following technique.

That is, in Patent Document 4, a hydrophilic treatment layer containing silica-based porous fine particles and a carboxyl group-containing polymer is provided on the surface of the substrate, and the adhesion amount of the silica-based porous fine particles and the carboxyl group-containing polymer An aluminum fin material for a heat exchanger whose content ratio is regulated within a predetermined range is disclosed.
And the technique which concerns on patent document 4 is that it can improve also about defrosting property and re-frosting prevention property while having the above characteristics, improving hydrophilic sustainability.

Japanese Patent Publication No. 3-77440 Japanese Patent No. 3191307 JP-A-9-14888 JP 2011-163714 A

  However, since the technique according to Patent Document 4 is not a technique that takes account of adhesion in a wet environment (specifically, adhesion between a base treatment layer and a hydrophilic treatment layer), fins in a wet environment such as the rainy season There is a possibility that the coating film may be peeled off when the material is pressed. As a result, the coating film peeled off during the press working of the fin material is deposited on the mold, which may cause a decrease in fin productivity and workability. Further, the defrosting property and the re-frosting prevention property may be lowered due to a decrease in the hydrophilicity of the portion where the coating film is peeled off.

  Furthermore, the fin material is also required to have a beautiful appearance with almost no color unevenness. In the fin material, if the coating film is evenly coated and has a beautiful appearance that does not easily discolor, it will be an assurance of performance and appeal of technical capabilities, and reliability of the product can also be obtained.

  However, since the technique according to Patent Document 4 is not a technique that takes into account the design of the appearance, the amount of silica-based porous fine particles attached is large and the appearance is considered white. In the white appearance, color unevenness occurs due to moisture absorption of silica-based porous fine particles and adhesion of fin press oil. In addition, in the white appearance, slight film unevenness becomes color unevenness and is easily noticeable.

  In other words, the technology according to Patent Document 4 has room for improving the adhesion in a wet environment, and the productivity, workability, defrosting, and re-generation due to insufficient adhesion in a wet environment. There is also room for preventing a decrease in anti-frosting property, and there is also room for improving the design of the appearance.

  Then, this invention makes it a subject to provide the aluminum fin material for heat exchangers which was excellent in hydrophilic sustainability, showed the favorable adhesiveness also in the humid environment, and was excellent in the design property.

  As a result of intensive studies to solve the above problems, the present inventors have provided a hydrophilic treatment layer containing silica-based porous fine particles, a carboxyl group-containing polymer, and a hydroxyl group-containing polymer on the substrate surface, The inventors have found that the above problems can be solved by regulating the ratio of each constituent material of the hydrophilic treatment layer to a predetermined range, and have completed the present invention.

That is, an aluminum fin material for a heat exchanger according to the present invention includes a substrate made of aluminum or an aluminum alloy, a corrosion-resistant film formed on the surface of the substrate, made of an inorganic oxide or an inorganic-organic composite compound, and a hydrophobic resin. A base treatment layer composed of at least one hydrophobic coating layer comprising: a surface treatment layer, and an average particle size of 0.1 to 10.0 μm and a pore diameter of 1 to 50 nm. And a hydrophilic treatment layer comprising a coating film containing a mixture of a silica-based porous fine particle, a water-soluble carboxyl group-containing polymer and a water-soluble hydroxyl group-containing polymer, and the silica in the hydrophilic treatment layer system attached amount of the porous fine particles is 1 to 100 mg / m ^2, relative to the total solid weight of said carboxyl group-containing polymer and the hydroxyl group-containing polymer The solid content weight ratio of the silica-based porous fine particles (that is, the solid content weight of the silica-based porous fine particles / the total solid content weight of the carboxyl group-containing polymer and the hydroxyl group-containing polymer) is 0.05 or more. The solid content weight ratio of the carboxyl group-containing polymer to the solid content weight of the hydroxyl group-containing polymer is less than 1.0 (that is, the solid content weight of the carboxyl group-containing polymer / the solid content of the hydroxyl group-containing polymer). The weight) is 0.1 to 10.0.

  Thus, the aluminum fin material for a heat exchanger according to the present invention includes a base treatment layer composed of at least one of a corrosion-resistant coating and a hydrophobic coating layer, so that condensed water that has permeated the hydrophilic treatment layer is separated from the substrate. Since contact can be prevented, corrosion resistance is improved.

Moreover, the aluminum fin material for heat exchangers according to the present invention can improve hydrophilicity by including silica-based porous fine particles having a predetermined average particle diameter and pore diameter in the hydrophilic treatment layer.
This is because the specific surface area of the particles increases due to the formation of pores on the surface of the silica-based porous fine particles, and the pores are exposed on the surface of the hydrophilic treatment layer when the particles are fine particles. This is due to a synergistic effect with an increase in the percentage of And when the specific surface area of the surface of a hydrophilic treatment layer increases, the area which water contacts will increase and hydrophilicity will improve.
As a result, the attached condensed water becomes a thin water film and easily flows down the fin material surface, so that frost is hardly generated. Further, the condensed water in the silica-based porous fine particles is present in a narrow space and has a feature that it is difficult to freeze. Therefore, in the defrosting cycle associated with the heating operation when used as a heat exchanger, the condensation inside the pores is not limited to the property that the condensed water is easily removed as a water film simply due to its excellent hydrophilicity. Since water is difficult to freeze, it has the characteristic that damage to the coating film associated with an increase in the volume of condensed water during freezing can be suppressed. That is, even after the defrosting cycle, the hydrophilicity is unlikely to deteriorate, thereby contributing to the frosting suppression effect.

  Furthermore, the aluminum fin material for a heat exchanger according to the present invention provides an appearance close to transparency by defining the amount of silica-based porous fine particles attached to the hydrophilic treatment layer, and colors such as coating unevenness and discoloration due to moisture absorption. It suppresses unevenness and improves design.

  In addition, in the aluminum fin material for heat exchangers according to the present invention, the silica-based porous fine particles are held in the hydrophilic treatment layer by the hydrophilic treatment layer including the carboxyl group-containing polymer and the hydroxyl group-containing polymer. In addition, the adhesion between the base treatment layer and the hydrophilic treatment layer is improved. As a result, the silica-based porous fine particles are prevented from flowing by the condensed water, and the hydrophilic sustainability is improved. And the inorganic silica-based porous fine particles have the property of easily sticking to the mold when the fin material is molded, but the mold of the silica-based porous fine particles is formed by the carboxyl group-containing polymer and the hydroxyl group-containing polymer. Since sticking to is prevented, workability is improved.

In addition, since the aluminum fin material for a heat exchanger according to the present invention includes a hydrophilic treatment layer containing a carboxyl group-containing polymer in a predetermined weight ratio with respect to the hydroxyl group-containing polymer, the hydroxyl group-containing polymer. By reacting with a carboxyl group-containing polymer (condensation reaction), it is possible to ensure adhesion between the base treatment layer and the hydrophilic treatment layer without impairing the hydrophilicity even in a wet environment.
In addition, by securing the adhesion between the base treatment layer and the hydrophilic treatment layer in a wet environment, the coating film (the base treatment layer, the hydrophilic treatment layer, etc.) can be peeled off when the fin material is pressed in the wet environment. As a result, it is possible to prevent the productivity, workability, defrostability and re-frosting prevention from being lowered.

  The aluminum fin material for heat exchanger according to the present invention is preferably formed by baking the hydrophilic treatment layer at a baking temperature of 190 to 300 ° C.

  Thus, the aluminum fin material for thermal ventilation according to the present invention can ensure the effect of improving adhesion by regulating the baking temperature of the hydrophilic treatment layer within a predetermined range.

  Moreover, it is preferable that the aluminum fin material for heat exchangers according to the present invention further includes a lubrication treatment layer made of a resin eluted in water on the surface of the hydrophilic treatment layer.

  Thus, when the aluminum fin material for heat exchangers according to the present invention includes the lubrication treatment layer, the hydrophilic treatment layer mainly containing an inorganic compound adheres to the mold when the fin material is molded. Therefore, workability is further improved. In addition, since the lubricating layer is made of a resin that elutes into water, the processing oil remaining on the surface of the fin material is washed away by the condensed water. Is further improved.

  Moreover, it is preferable that the aluminum fin material for heat exchangers according to the present invention includes a lubricating component in the hydrophilic treatment layer.

  Thus, the aluminum fin material for heat exchangers according to the present invention further improves the workability when the fin material is formed by including a lubricating component in the hydrophilic treatment layer.

The aluminum fin material for a heat exchanger according to the present invention includes a hydrophilic treatment layer containing silica-based porous fine particles, a carboxyl group-containing polymer, and a hydroxyl group-containing polymer on the substrate surface, and each constituent material of the hydrophilic treatment layer By regulating the ratio and the like within a predetermined range, it is excellent in hydrophilic sustainability, exhibits good adhesion even in a wet environment, and further exhibits excellent design properties.
Moreover, since the aluminum fin material for heat exchangers according to the present invention exhibits good adhesion even in a wet environment, peeling of the coating film (undercoat layer, hydrophilic treatment layer, etc.) during press processing of the fin material is possible. As a result, it is possible to prevent the productivity, workability, defrostability and re-frosting prevention from being lowered.

(A)-(d) is a cross-sectional schematic diagram which shows the structure of the aluminum fin material for heat exchangers which concerns on this invention. It is a figure explaining the process of drawless processing. It is a figure explaining the process of a draw process.

Hereinafter, a form (embodiment) for carrying out an aluminum fin material for a heat exchanger according to the present invention will be described with reference to the drawings as appropriate.
In the description of the second embodiment, the third embodiment, and the fourth embodiment, the description of the configuration that is common to the already described embodiments will be omitted, and the description will focus on the configuration that is different.

[First Embodiment]
<Aluminum fin material for heat exchanger>
As shown in FIG. 1A, an aluminum fin material for heat exchanger (hereinafter referred to as a fin material as appropriate) 1A according to the first embodiment includes a substrate 2 and a corrosion-resistant coating 3a formed on the surface of the substrate 2 ( A ground treatment layer 3) and a hydrophilic treatment layer 4 formed on the surface of the corrosion-resistant film 3a.

(substrate)
The substrate 2 is a plate material made of aluminum or an aluminum alloy, and is excellent in thermal conductivity and workability. Therefore, 1000 series aluminum specified in JIS H4000 is preferably used, and more preferably alloy numbers 1070, 1050, 1200 aluminum is used. In addition, as for the board | substrate 2, in the aluminum fin material 1 for heat exchangers, the board | substrate thickness of about 0.08-0.3 mm is used in consideration of an intensity | strength, heat conductivity, workability, etc. Moreover, the board | substrate 2 is manufactured to the board | plate material of desired thickness by well-known methods, such as casting, hot rolling, cold rolling, and tempering.

(Undercoat layer)
The base treatment layer 3 is composed of a corrosion-resistant film 3a made of an inorganic oxide or an inorganic-organic composite compound.
The inorganic oxide preferably contains Cr or Zr as a main component, and is formed by, for example, phosphoric acid chromate treatment, zirconium phosphate treatment, or chromate chromate treatment. However, in this invention, if it has corrosion resistance, it will not be limited to this, For example, the corrosion-resistant film | membrane 3a can be formed also by performing a zinc phosphate process and a phosphoric acid titanate process. The inorganic-organic composite compound is formed by performing a coating type chromate treatment or a coating type zirconium treatment, and examples thereof include an acryl-zirconium composite. The formation of the corrosion-resistant film 3a is performed, for example, by applying a chemical conversion treatment liquid to the substrate 2 by spraying or the like.

The corrosion-resistant film 3a preferably contains Cr or Zr in the range of 1 to 100 mg / m ² , and the film thickness of the base treatment layer 3 is preferably 10 to 1000 mm, but for the purpose of use, etc. Needless to say, it can be changed as appropriate. By forming the corrosion-resistant film 3a, the adhesion between the substrate 2 and the hydrophilic treatment layer 4 is improved, the contact of condensed water with the substrate 2 is suppressed, and corrosion resistance is imparted to the fin material 1.

(Hydrophilic treatment layer)
The hydrophilic treatment layer 4 is composed of a coating film containing a mixture of silica-based porous fine particles 4a, a water-soluble carboxyl group-containing polymer 4b, and a water-soluble hydroxyl group-containing polymer 4b. Formation of the hydrophilic treatment layer 4 imparts hydrophilic sustainability, processability, and adhesion in a wet environment to the fin material 1.
The hydrophilic treatment layer 4 is formed by dispersing the silica-based porous fine particles 4a in an aqueous solution of the water-soluble carboxyl group-containing polymer 4b and the water-soluble hydroxyl group-containing polymer 4b. It is carried out by applying and baking to the ground treatment layer 3.

In addition to the mixture of the silica-based porous fine particles 4a, the water-soluble carboxyl group-containing polymer 4b, and the water-soluble hydroxyl group-containing polymer 4b, the hydrophilic treatment layer 4 includes lubricity, paintability, appearance, etc. In addition, you may contain the chemical | medical agent for providing an additional characteristic.
Examples of agents (lubricating components) that impart lubricity include inner wax, and examples thereof include animal waxes such as lanolin, plant waxes such as carnauba, synthetic waxes such as polyethylene wax, and petroleum waxes. Species or two or more may be selected and used.
Examples of the agent imparting paintability include surfactants such as acetylene glycol, and examples thereof include Surfinol (registered trademark) manufactured by Nissin Chemical Industry Co., Ltd. Other agents that impart additional properties include pigments that are colored to impart design properties, such as Aqua Fine Color (AF Blue E-2B) manufactured by Dainichi Seika Kogyo Co., Ltd.

The silica-based porous fine particles 4a are manufactured by the manufacturing method described in, for example, Japanese Patent No. 3410634, and are pulverized by various pulverizers, and have an average particle size of 0.1 to 10.0 μm and fine pores. The diameter is 1 to 50 nm. And the adhesion amount of the silica type porous fine particle 4a in the hydrophilic treatment layer 4 is 1-100 mg / m < ² >.

  As the silica-based porous fine particles 4a, in addition to those made of pure silica, silica (aluminum (Al), titanium (Ti), magnesium (Mg), zirconium (Zr), gallium (Ga), beryllium (Be)) , Yttrium (Y), tin (Sn), vanadium (V), boron (B), and the like. However, these are mainly assumed to be inevitably mixed when the silica-based porous fine particles 4a are manufactured, and even if they are actively mixed, no special effect is obtained.

  The reasons for limiting the numerical values of the average particle diameter, the pore diameter, and the adhesion amount in the hydrophilic treatment layer 4 of the silica-based porous fine particles 4a are as follows.

If the average particle diameter of the silica-based porous fine particles 4a exceeds 10.0 μm, the silica-based porous fine particles 4a will settle in the paint even when trying to make a paint, so that the silica-based porous fine particles 4a are uniformly applied to the base treatment layer 3. Cannot be put to practical use. On the other hand, when the average particle size is less than 0.1 μm, it is scattered in the atmosphere during the preparation of the paint. Furthermore, as a general theory, there is a debate that there is a concern about safety of particles having a size of less than 0.1 μm regardless of the type of the particles, and thus it cannot be put into practical use.
The average particle diameter of the silica-based porous fine particles 4a is appropriately adjusted when pulverizing with various pulverizers as described above. The average particle diameter can be an integrated volume 50% particle diameter measured with a laser diffraction particle size distribution measuring instrument in a state where the silica-based porous fine particles 4a are dispersed in an aqueous solvent. It can also be measured using an electron micrograph or the like.

If the pore diameter of the silica-based porous fine particles 4a is less than 1 nm, it is technically impossible to manufacture. On the other hand, when the pore diameter exceeds 50 nm, it cannot be said to be a porous body, and a sufficient effect cannot be obtained. That is, excellent hydrophilic sustainability, defrosting property and anti-refrosting property cannot be obtained.
The pore diameter means the pore diameter that shows the maximum peak in the pore diameter distribution curve. The pore size distribution curve can be derived from an adsorption isotherm of a gas such as nitrogen by using a calculation method such as Cranston-Inklay method or Dollimore-Heal method.

When the adhesion amount of the silica-based porous fine particles 4a is less than 1 mg / m ² , the hydrophilic treatment layer 4 becomes a thin film, and excellent hydrophilic sustainability cannot be obtained. I do not get sex either. On the other hand, when the adhesion amount exceeds 100 mg / m ² , the hydrophilic treatment layer 4 becomes thick, and the appearance of the hydrophilic treatment layer 4 after coating becomes white, so that color unevenness and discoloration are likely to occur.
The adhesion amount of the silica-based porous fine particles 4a is preferably 10 mg / m ² or more in order to ensure the improvement of hydrophilicity retention, and to ensure the suppression of the occurrence of color unevenness. More preferably, it is 80 mg / m ² or less.

  The adhesion amount of the silica-based porous fine particles 4 a is appropriately adjusted depending on the content of the silica-based porous fine particles 4 a contained in the coating material and the coating amount of the coating material when applied to the base treatment layer 3. The adhesion amount of the silica-based porous fine particles 4a is measured by measuring the Si intensity with fluorescent X-rays.

  The silica-based porous fine particles 4a have a function of taking condensed water into the pores by having a pore diameter in a predetermined range. And since the inside of a pore is a narrow space, the condensed water taken in inside the pore is hard to freeze. Therefore, in the defrosting cycle accompanying the heating operation when used as a heat exchanger, the hydrophilic treatment layer 4 has a characteristic other than that it is easy to remove condensed water as a water film simply due to the hydrophilicity of the silica-based porous fine particles 4a. In addition, since the condensed water inside the pores is difficult to freeze, the hydrophilic treatment layer 4 can be prevented from being damaged due to an increase in the volume of the condensed water during freezing. That is, even after the defrosting cycle, the hydrophilicity of the hydrophilic treatment layer 4 is unlikely to deteriorate.

  The water-soluble carboxyl group-containing polymer 4b is a homopolymer obtained by homopolymerization or copolymerization of one or more carboxyl group-containing monomers selected from acrylic acid, methacrylic acid and itaconic acid. It is a copolymer or a copolymer obtained by copolymerizing one or two or more kinds of carboxyl group-containing monomers and other copolymerizable monomers.

  The water-soluble hydroxyl group-containing polymer 4b is a homopolymer or copolymer obtained by homopolymerization or copolymerization of one or more hydroxyl group-containing monomers selected from vinyl alcohol, ethylene glycol and propylene glycol. It is a copolymer or a copolymer obtained by copolymerizing one or two or more types of hydroxyl group-containing monomers with other copolymerizable monomers.

The water-soluble carboxyl group-containing polymer 4b and the water-soluble hydroxyl group-containing polymer 4b function as a binder that retains the silica-based porous fine particles 4a in the hydrophilic treatment layer 4 and does not impair the hydrophilicity.
And after forming a coating film by baking, since the carboxyl group-containing polymer 4b and the hydroxyl group-containing polymer 4b are not eluted into water, the adhesion between the hydrophilic treatment layer 4 and the base treatment layer 3 is ensured. For example, the silica-based porous fine particles 4a are less likely to flow due to condensed water generated during operation. Therefore, excellent hydrophilic sustainability can be obtained.

Furthermore, since the hydrophilic treatment layer 4 includes not only the carboxyl group-containing polymer 4b but also the hydroxyl group-containing polymer 4b, the hydroxyl group-containing polymer 4b reacts with the carboxyl group-containing polymer 4b (condensation reaction). By doing so, the adhesiveness of the base treatment layer 3 and the hydrophilic treatment layer 4 can be ensured without impairing the hydrophilicity even in a wet environment.
Therefore, for example, even when the fin material 1 is pressed in a wet environment such as the rainy season, the coating film (the base treatment layer 3, the hydrophilic treatment layer 4, etc.) is unlikely to peel off. By depositing the film on the mold, it is possible to avoid a situation where the productivity and workability of the fins are lowered. Moreover, possibility that defrosting property and re-frosting prevention property will fall can also be reduced by reducing the hydrophilic property of the part from which the coating film peeled.

The hydrophilic treatment layer 4 is preferably formed by baking at a baking temperature (plate arrival temperature) of 190 to 300 ° C.
When the baking temperature is less than 190 ° C., sufficient adhesion between the hydrophilic treatment layer 4 and the base treatment layer 3 cannot be ensured. On the other hand, when the baking temperature exceeds 300 ° C., not only the adhesion between the hydrophilic treatment layer 4 and the base treatment layer 3 but also the processability cannot be ensured sufficiently.

(Solid content weight ratio of each component of hydrophilic treatment layer)
In the hydrophilic treatment layer 4, the solid content weight ratio of the silica-based porous fine particles 4a to the total solid weight of the carboxyl group-containing polymer 4b and the hydroxyl group-containing polymer 4b (that is, the solid content of the silica-based porous fine particles 4a). Weight / total weight of solid content of carboxyl group-containing polymer 4b and hydroxyl group-containing polymer 4b) is 0.05 or more and less than 1.0.
When the solid content weight ratio is less than 0.05, the content ratio of the silica-based porous fine particles 4a is too low, so that the effect of improving the hydrophilic sustainability exhibited by the fine particles 4a cannot be sufficiently obtained. As a result, hydrophilic sustainability is lowered. On the other hand, when the solid content weight ratio is 1.0 or more, the content ratio of the silica-based porous fine particles 4a is too high, that is, the resin content ratio becomes low, and thus the adhesion in a wet environment. And corrosion resistance tends to decrease.

In the hydrophilic treatment layer 4, the solid content weight ratio of the carboxyl group-containing polymer 4b to the solid content weight of the hydroxyl group-containing polymer 4b (that is, the solid content weight of the carboxyl group-containing polymer 4b / the solid content of the hydroxyl group-containing polymer 4b). Weight) is 0.1 to 10.0.
If the solid content weight ratio is less than 0.1, the content ratio of the carboxyl group-containing polymer 4b is too low, so that the adhesion in a wet environment is lowered. Similarly, when the weight ratio of the solid content exceeds 10.0, the content ratio of the hydroxyl group-containing polymer 4b is too low, so that the adhesion in a wet environment is lowered.
That is, by restricting the content ratio of the carboxyl group-containing polymer 4b and the hydroxyl group-containing polymer 4b in the hydrophilic treatment layer 4 to a predetermined range, both polymers react appropriately (condensation reaction). Adhesiveness can be ensured.

[Second Embodiment]
<Aluminum fin material for heat exchanger>
As shown in FIG.1 (b), the aluminum fin material 1B for heat exchangers based on 2nd Embodiment is the board | substrate 2, the hydrophobic coating film layer 3b (base-treatment layer 3) formed in the surface of the board | substrate 2, and And a hydrophilic treatment layer 4 formed on the surface of the hydrophobic coating layer 3b.

(Undercoat layer)
The base treatment layer 3 includes a hydrophobic coating layer 3b made of a hydrophobic resin made of at least one of urethane resin, epoxy resin, polyester resin and polyacrylic acid resin.
By forming such a hydrophobic coating layer 3b, it is possible to suppress the condensed water that has permeated the hydrophilic treatment layer 4 from coming into contact with the substrate 2 even in a severe and humid environment such as an acidic atmosphere. Thereby, generation | occurrence | production of the aluminum oxide by corrosion (oxidation) of the board | substrate 2 is suppressed, and corrosion resistance is provided to the fin material 1. FIG. The hydrophobic coating layer 3b is formed by, for example, applying and baking a hydrophobic resin aqueous solution on the substrate 2.

  The thickness of the hydrophobic coating layer 3b is preferably 0.1 to 10 μm. When the film thickness is less than 0.1 μm, the penetration of condensed water from the hydrophilic treatment layer 4 cannot be prevented, and the corrosion resistance of the fin material 1 tends to be lowered. In general heat exchangers, a copper pipe is often used as the heat transfer pipe formed through the fin material 1, and when the thickness of the hydrophobic coating layer 3b exceeds 10 μm, the hydrophobic pipe layer 3b becomes hydrophobic. It is presumed that the contact heat resistance with the copper tube by the conductive coating layer 3b increases and the heat transfer performance decreases. Moreover, the film thickness exceeding 10 micrometers is not preferable also economically. In addition, the more preferable film thickness of the hydrophobic coating film layer 3b is 0.5-2 micrometers. With such a film thickness, the corrosion resistance of the fin material 1 is further enhanced.

[Third Embodiment]
<Aluminum fin material for heat exchanger>
As shown in FIG. 1C, an aluminum fin material for heat exchanger 1C according to the third embodiment includes a substrate 2, a corrosion-resistant film 3a (base treatment layer 3) formed on the surface of the substrate 2, and a corrosion-resistant film. And a hydrophobic coating layer 3b (base treatment layer 3) formed on the surface of 3a and a hydrophilic treatment layer 4 formed on the surface of the hydrophobic coating layer 3b.
When the base treatment layer 3 is composed of the corrosion-resistant film 3a and the hydrophobic coating layer 3b, it is preferable to form the corrosion-resistant film 3a on the substrate 2 side as shown in FIG. 1 (c).

[Fourth Embodiment]
<Aluminum fin material for heat exchanger>
As shown in FIG. 1 (d), the aluminum fin material for heat exchanger 1D according to the fourth embodiment includes a substrate 2, a ground treatment layer 3 formed on the surface of the substrate 2, and a surface of the ground treatment layer 3. The formed hydrophilic treatment layer 4 and the lubrication treatment layer 5 formed on the surface of the hydrophilic treatment layer 4 are provided.
The base treatment layer 3 may be composed of the corrosion-resistant film 3a, the hydrophobic coating layer 3b, or the corrosion-resistant film 3a and the hydrophobic coating layer 3b.

(Lubricated layer)
The lubricating treatment layer 5 is made of a resin that elutes into water, for example, polyethylene glycol, modified polyethylene glycol, or polyvinyl alcohol, and is formed with a film thickness of 0.01 to 1 μm. The formation of the lubricating treatment layer 5 is carried out by applying and baking an aqueous solution of a resin eluting into water on the hydrophilic treatment layer 4.

  The lubricating treatment layer 5 is eluted in the condensed water adhering to the fin surface during operation of the heat exchanger, and the molding oil remaining on the fin surface can be washed away by the condensed water. Thereby, a decrease in hydrophilic sustainability caused by molding processing oil or the like is suppressed. Further, since the hydrophilic treatment layer 4 is composed of an inorganic compound, the hydrophilic treatment layer 4 may stick to the mold when the fin material 1 is molded. The adhesion can be suppressed. As a result, workability is improved.

  When the film thickness of the lubrication treatment layer 5 is less than 0.01 μm, adhesion of the hydrophilic treatment layer 4 to the mold cannot be suppressed during molding of the fin material 1, and excellent workability ( It is difficult to obtain tool wear. Further, when the film thickness exceeds 1 μm, the surface of the lubricating treatment layer 5 becomes sticky due to the moisture absorption effect of the lubricating treatment layer 5 itself, so that it is wound around the mold during the molding process of the fin material 1 ), Can not be processed well.

  1A to 1D, the case where the base treatment layer 3, the hydrophilic treatment layer 4 and the lubrication treatment layer 5 are formed on one side of the substrate 2 has been described. It may be formed.

[Method for producing aluminum fin material for heat exchanger]
Next, an example of the manufacturing method of the aluminum fin material for heat exchangers will be described.
Below, the manufacturing method of 1 C of aluminum fin materials for heat exchangers shown in FIG.1 (c) is demonstrated.

(1) The surface of the substrate 2 made of aluminum or an aluminum alloy is subjected to a phosphoric acid chromate treatment, a zirconium phosphate treatment, or the like, thereby forming a corrosion-resistant film 3a made of an inorganic oxide or an inorganic-organic composite compound. Here, the phosphoric acid chromate treatment, the zirconium phosphate treatment, and the like are performed by applying a chemical conversion treatment solution to the substrate 2 by spraying or the like. The coating amount is preferably 1 to 100 mg / m ^{2 in} terms of Cr or Zr, and the formed film thickness is preferably 10 to 1000 mm. Moreover, before forming the corrosion-resistant film 3a, it is preferable to degrease the surface of the substrate 2 in advance by spraying an alkaline aqueous solution or the like on the surface of the substrate 2. The adhesion between the substrate 2 and the base treatment layer 3 is improved by degreasing.

(2) An aqueous solution of a hydrophobic resin is applied to the surface of the formed corrosion-resistant coating 3a and then baked to form the hydrophobic coating layer 3b. The coating method is performed by a conventionally known coating method such as a bar coater or a roll coater, and the coating amount is appropriately set (prepared) so that the thickness of the hydrophobic coating layer 3b is 0.1 to 10 μm. The baking temperature (the temperature reached by the aluminum plate) is appropriately set depending on the hydrophobic resin to be applied, but is generally in the range of 150 to 300 ° C.

(3) Silica-based porous fine particles 4a having an average particle diameter of 0.1 to 10 μm and a pore diameter of 1 to 50 nm and a water-soluble carboxyl group on the surface of the formed hydrophobic coating layer 3b After applying an aqueous dispersion composed of a mixture of the polymer 4b and the water-soluble hydroxyl group-containing polymer 4b, baking is performed to form the hydrophilic treatment layer 4 to obtain the fin material 1. The coating method is performed by a conventionally known coating method such as a bar coater or a roll coater, and the coating amount is appropriately set (prepared so that 1 to 100 mg / m ² of silica-based porous fine particles 4a in the hydrophilic treatment layer 4 are adhered). ) The baking temperature (the temperature reached by the aluminum plate) is appropriately set depending on the aqueous dispersion to be applied, but as described above, it is preferably performed in the range of 190 to 300 ° C.

Moreover, when manufacturing fin material 1D shown by FIG.1 (d), after performing said (1)-(3), following (4) is performed.
(4) An aqueous solution of a resin (water-soluble resin) that elutes into water is applied to the surface of the formed hydrophilic treatment layer 4 and then baked to form the lubrication treatment layer 5. The coating method is performed by a conventionally known coating method such as a bar coater or a roll coater, and the coating amount is appropriately set (prepared) so that the thickness of the lubricating treatment layer 5 is 0.01 to 1 μm. The baking temperature (the temperature reached by the aluminum plate) is appropriately set depending on the aqueous solution to be applied, but is generally in the range of 100 ° C to 200 ° C.

  When the fin material produced by the above-described manufacturing method is used as an aluminum fin for a heat exchanger, as shown in FIGS. 2 and 3, a heat transfer tube made of a copper tube or the like in the thickness direction of the fin material 1 is used. A through-hole 10 b through which (not shown) passes is formed into a fin 10. And as a shaping | molding processing method, a draw-less process, a draw process, etc. are used, for example.

  As shown in FIG. 2, the drawless process can form the collar portion 10 a having the through hole 10 b through which the heat transfer tube passes with fewer processes than the draw process, and includes a pierce burring process, a first ironing process, and a second ironing process. The collar portion 10a (through hole 10b) is formed on the fin material 1 in four steps, a step and a flaring step.

  As shown in FIG. 3, the drawing process is the most common molding process conventionally performed. The first drawing process, the second drawing process, the third drawing process, the fourth drawing process, the pierce burring process, The collar portion 10a (through hole 10b) is formed on the fin material 1 in six steps of the flaring step.

  Further, the present invention will be specifically described with reference to examples and comparative examples.

  The fin material was produced by the following method. As the substrate, an aluminum plate having a thickness of 0.1 mm made of aluminum with an alloy number of 1200 specified in JIS H4000 was used.

A phosphoric acid chromate treatment for forming a corrosion-resistant film was performed on one surface of the aluminum plate. As the chemical conversion treatment liquid, Alsurf (registered trademark) 401/45, phosphoric acid, and chromic acid manufactured by Nippon Paint Co., Ltd. were used. The film thickness of the corrosion-resistant film at this time was 400 mm (Cr conversion value measured by the fluorescent X-ray method was 20 mg / m ² ).

  A material having a hydrophobic coating layer (film thickness: 1.0 μm) formed on one side of this corrosion-resistant film or aluminum plate was also produced. The hydrophobic coating layer was formed by applying and baking a urethane resin paint (manufactured by Toho Chemical Co., Ltd., urethane-modified resin emulsion, Hitech (registered trademark) S-6254). The baking temperature was 160 ° C. at the temperature reached by the aluminum plate. The thus prepared corrosion-resistant film and hydrophobic coating layer were collectively used as a base treatment layer.

On one side of this base treatment layer, silica-based porous fine particles (Silicia (registered trademark) 420, manufactured by Fuji Silysia Co., Ltd.), water-soluble carboxyl group-containing polymers and water-soluble particles having an average particle diameter and pore diameter shown in Table 1 are used. An aqueous dispersion (coating material) for adhering a mixture with a hydrophilic hydroxyl group-containing polymer was applied and baked to form a hydrophilic treatment layer in which the attached amount of silica-based porous fine particles was Table 1.
The baking was performed at the baking temperature shown in Table 1 (maximum temperature reached: PMT).

As the water-soluble carboxyl group-containing polymer, polyacrylic acid (manufactured by Toagosei Co., Ltd., Jurimer (registered trademark) AC-10H) was used.
Polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol (registered trademark) NL-05) was used as the water-soluble hydroxyl group-containing polymer.

  In addition, as a combination of carboxyl group-containing polymer / hydroxyl group-containing polymer, a hydrophilic treatment layer is formed using a combination of polyacrylic acid / PEG (polyethylene glycol) instead of the above-described substances (Sample No. 9). ), A methacrylic acid / PVA (polyvinyl alcohol) combination used to form a hydrophilic treatment layer (sample No. 10), and a polyethylene wax as a chemical imparting lubricity (lubricating component) is added to form a hydrophilic treatment layer. What was formed (sample No. 13), what formed the hydrophilic treatment layer without using resin (sample No. 22), and what formed the hydrophilic treatment layer using epoxy resin (sample No. 27) were also produced. did.

  In addition, a silica fine particle having no pores (manufactured by Nissan Chemical Industries, Ltd., Snowtex (registered trademark) XL: particle diameter 40-60 nm) formed with a hydrophilic treatment layer (sample No. 28), What was formed by applying and baking a hydrophilic treatment layer (film thickness 0.05 μm) made of a silicate compound and polyacrylic acid without using silica-based fine particles (baking temperature is 200 ° C. at the temperature reached by the aluminum plate) (Sample No. .29) was also produced.

  The average particle diameter of the silica-based porous fine particles was measured with an optical micrograph. As the pore diameter of the silica-based porous fine particles, the pore diameter showing the maximum peak calculated from the pore diameter distribution curve derived from the nitrogen adsorption isotherm by the Cranston-Inkley method was used. Furthermore, the adhesion amount of the silica-based porous fine particles was measured by the Si intensity by fluorescent X-rays.

Then, the fin material was manufactured by forming a lubrication treatment layer on one side of the hydrophilic treatment layer.
The lubrication treatment layer was formed by applying an aqueous polyvinyl alcohol solution on one surface of the hydrophilic treatment layer and baking it to obtain the film thickness shown in Table 1. The baking temperature was 200 ° C. at the ultimate temperature of the aluminum plate.

  About the produced fin material (sample No. 1-29), the following methods evaluated hydrophilic sustainability, defrosting property, re-frosting prevention property, adhesiveness, workability, corrosion resistance, and design property.

<Hydrophilic (after defrost cycle)>
The hydrophilicity, defrosting property and anti-refrosting property were evaluated based on hydrophilicity (after defrosting cycle).
For hydrophilicity (after defrosting cycle), the fin material is pasted on the cooled box surface at −10 ° C. for 1 hour and held to form frost on the fin material surface, and then melted at 50 ° C. for 10 minutes. The treatment was set to 1 cycle, and after 15 cycles were applied to the fin material, the surface tension at the time of immersion in pure water was converted into an advancing contact angle and evaluated using a surface tension meter. Immersion was repeated three times, and the second and third measurement values were judged as accurate measurement values, and an average value was calculated from the two measurement values.
A case where the contact angle calculated as an average value is less than 10 ° is a very preferable state (◯), a case where the contact angle is 10 ° or more and less than 30 ° is a preferable state (Δ), and a case where the contact angle is 30 ° or more is not preferable. The state (x) was regarded as acceptable, and the state (◯) and (Δ) were regarded as acceptable.

<Adhesion>
Adhesion was achieved by conducting a rubbing test in which two wipes of Kimwipe (registered trademark) S200 impregnated with 1 ml of ion-exchanged water were wound around the tip of a 2-lb hammer and the fin material surface was reciprocated 100 times. By measuring the strength of the film, the amount of film (the amount of the hydrophilic treatment layer) between the part where the rubbing test was conducted in the longitudinal direction and the part where the rubbing test was not carried out was measured, and the residual rate of the film was calculated and evaluated.
A state where the calculated film residual ratio is 90% or more is very preferable (◯), a case where the film residual ratio is 70% or more and less than 90% is preferable (Δ), and the film residual ratio is 70%. The case of less than% was regarded as an unfavorable state (x), and the state of (◯) and (Δ) was regarded as acceptable.

<Processability>
As for workability, the fin material 1 is subjected to drawless processing (see FIG. 2) and draw processing (see FIG. 3) to produce the fin 10, and the moldability of the collar portion 10a of the fin 10 after continuous 10,000 shots is performed. Evaluation was made by visual confirmation.
The case where molding defects such as seizure were not confirmed on the inner surface of the collar portion 10a of the fin 10 after molding was determined to be acceptable (O), and the case where molding defects were confirmed was determined to be unacceptable (X). In addition, the case where it passed ((circle)) at least one of the drawless process and the draw process was set as the pass ((circle)) in workability.

<Corrosion resistance>
Corrosion resistance was evaluated in accordance with JIS Z 2371 by a rating number corresponding to the corrosion area ratio when the salt spray test was performed on the fin material for 200 hours.
A case where the rating number was 9.8 or more was rated (◯), a case where the rating number was 9.5 or more and less than 9.8 was (Δ), and a case where the rating number was less than 9.5 was (x). The state of ((circle)) and ((triangle | delta)) was set as the pass.

<Designability>
About the designability (color unevenness), the lightness L value before submerging of the fin material and immediately after submerging was evaluated by a SCE method using a spectrocolorimeter (manufactured by Konica Minolta Co., Ltd.). The submerged time of the fin material was 1 minute.
When the difference in L value before and after submergence (before submergence-after submergence = ΔL) is less than 1, (○), when less than 3 but less than 3, (△), when more than 3 (×), The state of (△) was set to pass.

Table 1 shows the evaluation results of hydrophilicity (after the defrosting cycle), adhesion, workability, corrosion resistance, and design of the fin material (sample Nos. 1 to 29).
In addition, the underline in Table 1 indicates that the requirements defined in the present invention are not satisfied.

  As shown in Table 1, since Examples (Sample Nos. 1 to 13) satisfy the requirements of the present invention, hydrophilicity (wearing) is an index of hydrophilic sustainability, defrosting property, and anti-refrosting property. After the defrost cycle) passed, and adhesion, workability, corrosion resistance and design were also passed. Hereinafter, “hydrophilicity (after defrosting cycle)” is referred to as “hydrophilicity”.

In the example (sample No. 3) that does not include the lubrication treatment layer and the example (sample No. 12) in which the baking temperature exceeds the range defined by the present invention, in the ironing process of the drawless process, Although molding defects due to the shortage were confirmed, no molding defects were confirmed in the drawing process, so the workability was accepted.
Moreover, although the example (sample No. 11) in which the baking temperature of the hydrophilic treatment layer is less than the range defined by the present invention was evaluated that all items were acceptable, the adhesion and corrosion resistance were not good. The evaluation was limited to △.

  On the other hand, since the comparative examples (sample Nos. 14 to 29) do not satisfy any of the requirements of the present invention, at least one evaluation item among hydrophilicity, adhesion, workability, corrosion resistance, and design properties The result was a failure.

  Specifically, since the comparative example (sample No. 14) did not include the base treatment layer, the corrosion resistance was rejected. The comparative example (sample No. 15) was not practical because the porous fine particles could not be produced because the pore diameter of the silica-based porous fine particles was less than the lower limit. In Comparative Example (Sample No. 16), since the pore diameter of the silica-based porous fine particles exceeded the upper limit value, the hydrophilicity was unacceptable. Since the average particle diameter of the silica-based porous fine particles was less than the lower limit value, Comparative Example (Sample No. 17) was not practical due to safety concerns. In Comparative Example (Sample No. 18), since the average particle diameter of the silica-based porous fine particles exceeded the upper limit, a coating for a hydrophilic treatment layer could not be prepared and was not practical.

  In Comparative Example (Sample No. 19), the adhesion amount of the silica-based porous fine particles was less than the lower limit value, and thus the hydrophilicity was unacceptable. In Comparative Examples (Sample No. 20) and (Sample No. 21), the adhering amount of the silica-based porous fine particles exceeded the upper limit value, and thus the design properties were unacceptable. In the comparative example (sample No. 21), since the adhesion amount of the silica-based porous fine particles greatly exceeded the upper limit value, not only the design property but also the workability was rejected. Since the comparative example (sample No. 22) did not apply the carboxyl group-containing polymer or the hydroxyl group-containing polymer to the hydrophilic treatment layer, the hydrophilicity and adhesion were unacceptable.

  In Comparative Example (Sample No. 23), the solid content weight ratio of the silica-based porous fine particles in the hydrophilic treatment layer exceeded the upper limit value, and thus the adhesion was unacceptable. Since the comparative example (sample No. 24) had a solid content weight ratio of the silica-based porous fine particles of the hydrophilic treatment layer less than the lower limit, the hydrophilicity was unacceptable. In Comparative Example (Sample No. 25), the solid content weight ratio of the carboxyl group-containing polymer to the hydroxyl group-containing polymer of the hydrophilic treatment layer was less than the lower limit value, and thus the adhesion was unacceptable. In Comparative Example (Sample No. 26), the solid content weight ratio of the carboxyl group-containing polymer to the hydroxyl group-containing polymer of the hydrophilic treatment layer exceeded the upper limit value, and thus the adhesion was unacceptable.

  Since the comparative example (sample No. 27) applied the hydrophobic resin to the hydrophilic treatment layer, the hydrophilicity was unacceptable. Since the comparative example (sample No. 28) applied fine particles having no pores, the hydrophilicity was unacceptable. The comparative example (Sample No. 29) was unsatisfactory in hydrophilicity because the configuration of the hydrophilic treatment layer was different from that defined in the present invention.

  The comparative example (Sample No. 29) has the same configuration as that of the fin material described in Patent Document 2 except that a base treatment layer is provided.

  As mentioned above, although the aluminum fin material for heat exchangers according to the present invention has been described in detail with reference to the embodiments and examples, the gist of the present invention is not limited to the above-described contents, and the description of the scope of claims. Needless to say, modifications and changes can be made based on the above.

1 Aluminum fin material for heat exchanger (fin material)
1A Aluminum fin material for heat exchanger (fin material) according to the first embodiment
1B Aluminum fin material for heat exchanger (fin material) according to the second embodiment
1C Aluminum fin material for heat exchanger (fin material) according to the third embodiment
1D Aluminum fin material for heat exchanger (fin material) according to the fourth embodiment
2 Substrate 3 Base treatment layer 3a Corrosion resistant coating 3b Hydrophobic coating layer 4 Hydrophilic treatment layer 4a Silica-based porous fine particle 4b Carboxyl group-containing polymer and hydroxyl group-containing polymer (carboxyl group-containing polymer, hydroxyl group-containing polymer and lubricating component) )
5 Lubrication layer

Claims (4)

A substrate made of aluminum or an aluminum alloy;
A base treatment layer formed on at least one of a corrosion-resistant film made of an inorganic oxide or an inorganic-organic composite compound, and a hydrophobic coating layer made of a hydrophobic resin, formed on the surface of the substrate;
Silica-based porous fine particles, water-soluble carboxyl group-containing polymer and water-soluble polymer having an average particle diameter of 0.1 to 10.0 μm and a pore diameter of 1 to 50 nm formed on the surface of the base treatment layer A hydrophilic treatment layer composed of a coating film containing a mixture with a hydroxyl group-containing polymer of
Adhered amount of the silica-based porous material fine particles in the hydrophilic treatment layer is 1 to 100 mg / ^{m 2,}
The solid content weight ratio of the silica-based porous fine particles to the total solid content weight of the carboxyl group-containing polymer and the hydroxyl group-containing polymer is 0.05 or more and less than 1.0,
The aluminum fin material for heat exchangers, wherein a solid content weight ratio of the carboxyl group-containing polymer to a solid content weight of the hydroxyl group-containing polymer is 0.1 to 10.0.   The aluminum fin material for a heat exchanger according to claim 1, wherein the hydrophilic treatment layer is formed by baking at a baking temperature of 190 to 300 ° C.   The aluminum fin material for a heat exchanger according to claim 1 or 2, further comprising a lubrication treatment layer made of a resin eluted in water on the surface of the hydrophilic treatment layer.   The said hydrophilic treatment layer further contains a lubrication component, The aluminum fin material for heat exchangers of any one of Claim 1 thru | or 3 characterized by the above-mentioned.

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