JPH0857414A - A1 or a1 alloy fin material of superior hydrophilic nature - Google Patents

Abstract

PURPOSE: To provide an A1 alloy fin material of high performance in which stabilized hydrophilic continuous nature is demonstrated securely and pressure loss or lowering of heat exchange efficiency composed by remaining condensed water or the like even in the case of continuous operation for a long time by forming a film on the surface of an A1 alloy fin material. CONSTITUTION: A resin film of superior hydrophilic mature composed of a polymer compound of interaction energy (ΔE0 ) of 1.0Kcal/mol or more per one molecule of water found by the following formula as a main component is formed on the surface of an A1 or A1 alloy fin material. In the formula of ΔE0 =(Ew +Ep -Ew-p )/NH2 O, Ew represents the energy of an aggregate of water molecule only, Ep represents energy of polymer compound model molecule only, Ew-p is energy of hydrated polymer compound model molecule and NH2 O represents the number of hydrated water molecules.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin material made of Al or Al alloy (hereinafter represented by Al alloy) having excellent hydrophilicity, and in particular, a polymer compound having excellent hydrophilicity on its surface. The present invention relates to an Al alloy fin material in which the water content of the fin material is enhanced by forming a resin coating film, and the heat exchange efficiency is enhanced by improving the flow of condensed water. Also, it exhibits excellent effects as a fin material for a heat exchanger in an air conditioner for business use or a home, and also for an air conditioner for an automobile, a vehicle, an aircraft, and the like.

[0002]

2. Description of the Related Art Since Al alloys are lightweight and have excellent heat conductivity, formability, corrosion resistance, etc., they are widely used as fin materials for heat exchangers for air conditioners as described above. Has been done. However, it has been pointed out that the fin material made of Al alloy has a problem that the ventilation resistance increases due to the attachment and retention of condensed water during use, and the heat exchange efficiency decreases.

Therefore, as a means for improving such difficulties, Al before being formed as a fin material for a heat exchanger is used.
Hydrophilic treatment is applied to the surface of the alloy plate to improve water wettability so that condensed water can form a water film and quickly flow down, thereby making it possible to use it when assembled and used as a heat exchanger. Methods for reducing ventilation resistance, increasing heat exchange efficiency, suppressing power loss, suppressing noise, and preventing water droplets from being scattered have been implemented.

The hydrophilic treatment method for the surface of the Al alloy fin material includes (1) a method of applying water glass to the surface (see, for example, Japanese Patent Laid-Open Publication No.
(8-126989, etc.) (2) A method of forming a film in which silica, water glass, aluminum hydroxide, calcium carbonate, titania or the like is mixed with an organic resin, or a hydrophilic film in which a surfactant is mixed (for example, JP-A-55-99976 and 60-
No. 101156, etc.) (3) A method of subjecting the surface of an Al alloy plate to a boehmite treatment or an alumina treatment (for example, JP-A-56-20971, etc.) (4) Water-soluble or water-soluble hydrophilic acrylic resin, water-soluble cellulose or the like A method of applying a coating liquid containing a cross-linking agent, a surfactant, a chelating agent, etc. to a dispersible organic resin (for example,
JP-A-62-186198, etc.) are known, and some of them are already in practical use.

However, each of the above methods has the following drawbacks. That is, in the above methods (1) to (3), since the main component that exhibits hydrophilicity is an inorganic compound, the ductility of the film is poor, and cracks are formed in the film during overhang forming or ironing when forming into a fin shape. May enter and may propagate to the material and cause cracks in the Al alloy plate.
That is, it is pointed out that there is a big problem that the formability is remarkably lowered as compared with the untreated material which is not surface-treated.

On the other hand, as in the above method (4), an organic compound containing a water-soluble or water-dispersible resin as a main component, which is composed of an organic polymer compound such as an acrylic type, a cellulose type, a vinyl alcohol type, a urethane type or the like, is used. In the case where a hydrophilic resin film is provided, the film itself has ductility,
As pointed out in the above inorganic coating, it does not adversely affect the moldability of the material, and exhibits excellent performance in terms of initial hydrophilicity. However, these polymer compound-based hydrophilic resin coatings may exhibit an excellent hydrophilic sustaining effect depending on the type of polymer compound, but depending on the type, they can be used on the fin due to continued use of the heat exchanger. Condensation and water flowing down gradually dissolve the polymer compound,
Alternatively, the oil content in the air during the drying operation causes water repellency, which may make it impossible to maintain high hydrophilicity for a long time.

The reason why there is a difference in the hydrophilic durability of the film depending on the kind of the hydrophilic polymer compound used is as follows.
It has not been theoretically elucidated and goes through trial and error. At present, various hydrophilic polymer compounds are actually used to form a film on the surface of an Al alloy plate, and the initial hydrophilicity and long-term The reality is that the type of polymer compound is selected after confirming the hydrophilic sustainability at each use.

However, it is almost impossible to confirm the hydrophilicity and long-term hydrophilicity sustaining effect of all of the innumerable polymer compounds by experiments, and the hydrophilic surface film constituent material for the Al alloy fin material is almost impossible. If the sustainability of hydrophilicity of a polymer compound can be easily determined from a simple evaluation method or an index specific to the polymer compound used, the selection criteria for the hydrophilic polymer compound will become clear, and preliminary practical application will be possible. It is considered that a high-performance hydrophilic film-forming Al compound fin material can be stably provided without requiring a test.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to
Established a method for evaluating the suitability of polymer compounds as a hydrophilicity-imparting film-forming material for alloy fin materials, which ensures excellent water wettability even when the condensation and drying operations are repeated for a long period of time. Al with a hydrophilic film
It is intended to provide an alloy fin material.

[0010]

The structure of the fin material made of Al or Al alloy according to the present invention, which has been capable of solving the above-mentioned problems, is Al or Al in which a resin film having a polymer compound as an essential component is formed. In the alloy fin material, water 1 calculated by the following formula (1) as a polymer compound
Interaction energy (ΔE ₀ ) with each molecule is 1.0
The gist of the invention is that it is used by selecting one having a Kcal / mol or more. ΔE ₀ = (E _W + E _P −E _WP ) / N _H2O (1) In the formula, E _W is the energy of the aggregate of water molecules alone E _P is the energy of the polymer compound model molecule alone E _WP is the hydration The energy N _H2O of the model molecule of the polymer compound represents the number of hydrated water molecules.

Particularly preferred as the polymer compound having the above interaction energy is a polymer containing (meth) acrylic acid or vinyl alcohol as a polymerized unit, a cellulosic compound or a mixture thereof, and the polymer compound-containing resin. The system coating preferably contains a metal chelate cross-linking agent or a surfactant, and the one having a corrosion resistant coating formed as an underlayer of the polymer compound-containing resin coating has excellent durability in combination with improved corrosion resistance. It has the property.

[0012]

As described above, in the present invention, the hydrophilicity of the film containing an organic polymer compound as a main component is utilized to enhance the water wettability of the film. The quality can be evaluated to some extent by the rising angle (contact angle with water) of the water droplet when the water droplet is dripped onto the surface of the coating, and the hydrophilicity of the hydrophilic coating formed on the fin material surface is It can be said that the smaller the contact angle, the better. However, it takes a lot of labor to measure the contact angle of numerous commercially available polymer compounds with water and evaluate the suitability as a hydrophilic film forming material formed on the fin material surface, and it is necessary for practical use. Not a suitable evaluation method.

Therefore, the present inventors can easily, quickly and accurately evaluate the hydrophilicity required as a film constituent material for fin materials from among the various characteristics originally possessed by polymer compounds. As a result of research from various angles, the value of interaction energy with various water molecules of various polymer compounds obtained by the equation (1) by calculation based on the molecular mechanics method is Knowing that it accurately reflects the quality, the completion of the present invention is seen here.

In the above equation (1), E _w , E _p , E
_wp is the potential function (E) expressed by the following equation (2), using the atomic species that make up each molecule and their coordinates.
Calculated by E = E _b + E θ + E φ + E _i + E _vdw + E _el + E _hb …… (2) E _b = 1 / 2K _b (rr ₀ ) ² E _θ = 1 / 2K θ (θ-θ ₀ ) ² E φ = 1 / 2K φ [1 + d・ Cos (nφ)] E _i = 1/2 (cosω-cosω ₀ ) ² E _vdw ＝ D ₀ [(R ₀ / R) ¹² -2 (R / R ₀ ) ⁶ ] E _el ＝ 332.0637Q _i Q _j / R _ij E _hb = D ₀ [(R ₀ / R) ¹² -2 (R / R ₀ ) ¹⁰ ]

In the above equation, r, θ, φ, ω, R,
R _ij is a variable determined by atomic coordinates such as the interatomic distance and bond angle, and K _b , r _o , Kθ, θ
₀ , Kφ, d, n, ω ₀ , D ₀ and R ₀ are parameters determined for each atomic species, and Q _i and Q _j are charges of each atom. Parameters determined for each atomic species are described in the literature "Mayo, SL, Olaf
son, BD, GoddardIII, WA, J. Phys. Chem., 1990,
94 , 8897-8909 ".

That is, first, a polymer molecule model is prepared by linearly connecting 10 to 20 monomer molecule models. A hydrated polymer model molecule is prepared by arranging a water molecule in the space around the polymer molecule model, that is, in a position of 2.8 to 5.6Å from the surface of the polymer molecule. Based on these molecular structures, the molecular energy is calculated according to the formula (2) while changing the atomic coordinates to obtain the molecular structure (stabilized structure I) that minimizes the value of the formula (2) (structure optimization). Calculation). The energy of this stabilizing structure is E _wp . Next, the polymer molecular model is removed from the stabilized structure I, and the energy is calculated by the above equation (2) in the state where only water molecules remain, and is designated as E _w . On the other hand, the water molecules are removed from the stabilized structure I, and the energy is calculated by the equation (2) in the state where only the polymer molecule model remains, and is set as E _p .

By _obtaining (E _W + E _P −E _WP ) from the thus obtained E _W , E _P , and E _WP , the interaction energy (ΔE) between the water molecule aggregate and the polymer model molecule can be obtained, By dividing this by the number of water molecules, the interaction energy (ΔE ₀ ) of the polymer molecule per water molecule can be obtained.

As is clear from the examples described later, the interaction energy (ΔE ₀ ) is 1.0 Kc.
al / mol or more, more preferably 1.5 Kcal / m
If a polymer compound having an ol or more is selected and used as the main component of the hydrophilic coating, the hydrophilicity of the Al alloy fin material is stable not only in the initial hydrophilicity but also in the long-term hydrophilicity and maintaining a very excellent performance. It was confirmed that a chemical film can be formed.

In the present invention, the selection criteria of the polymer compound selected as the main component of the hydrophilic film are water 1 as described above.
Although it is the interaction energy with per molecule, in selecting it, it is good to select one that can form a film with excellent flexibility in consideration of adhesion and moldability to the Al alloy substrate, which is preferable. Examples include poly (meth) acrylic acid, alkali metal salts of poly (meth) acrylic acid, copolymers of poly (meth) acrylic acid and polyvinyl acetate, and poly (meth) acrylic acid and polyvinyl alcohol. Copolymer, copolymer of poly (meth) acrylic acid and cellulose, copolymer of poly (meth) acrylic acid and starch, poly (meth) acrylamide, poly (meth)
Acrylamide methyl propane sulfonic acid, copolymer of (meth) acrylic acid and polyamide, polyvinyl alcohol, partially saponified polyvinyl acetate, cellulosic resin (hydroxypropyl cellulose, carboxymethyl cellulose, water-soluble cellulose such as methyl cellulose)
And the like. These can be used as a homopolymer or a copolymer, or as a mixture of two or more kinds.

The hydrophilic polymer compound as described above forms a film exhibiting excellent water wettability when used by itself as a hydrophilic film constituent material. It is preferable to use an agent in combination because the properties thereof, particularly the hydrophilic lasting property, can be further enhanced.
That is, it is extremely important for this film to have durability of hydrophilicity in addition to initial hydrophilicity, that is, long-term hydrophilic lasting. To obtain a film having long-term hydrophilic lasting, a hydrophilic film is required. It is effective to enhance long-term adhesion with the base material. For that purpose, the molecular weight of the polymer compound is increased to suppress entrainment / outflow of condensed water from the surface of the fin material, and the corrosion resistance formed as a hydrophilic film and a base material or, if necessary, an undercoat layer. It is effective to increase the adhesion by bonding with the film, but from the viewpoint of increasing the molecular weight of the film constituent material or enhancing the adhesion to the substrate and substrate, it is extremely difficult to add an appropriate amount of cross-linking agent to the film. It is valid.

The cross-linking agent used here is Ti,
Examples thereof include chelates such as Zr, Al and Zn, metal salts and metal complexes containing ionomer-forming metals, and alkoxide compounds known as organic coordinating compounds.
These may be used alone or in combination of two or more if necessary. These cross-linking agents cause a cross-linking reaction or a coordinate bond with the water-soluble or water-dispersible polymer compound to increase the molecular weight of the film-constituting resin, thereby increasing the hydrophilic durability as described above and forming an undercoat film. It exerts the effect of further enhancing the adhesion.

In the present invention, it is effective to add a surfactant as another additive. That is, the surfactant mainly serves to improve the initial hydrophilicity and to prevent the hydrophilicity from being deteriorated due to the adsorption of the press oil applied during the fin-shaped forming process. Enhances initial hydrophilicity when used as
In addition, there is no limitation on the kind as long as it is capable of causing the press oil and the like to flow out when it flows out together with the water condensed on the fins, and any of anionic, nonionic, cationic and amphoteric surfactants can be used. May be used. Typical examples are alkyl sulfonic acid ester salts and polyoxyethylene alkylphenyl ether sulfates as anionic compounds, and polyoxyethylene alkylphenyl ethers and polyoxyethylene / polyoxypropylene copolymer fatty acid esters as nonionic compounds. Examples of the cationic type include alkylamine salts and alkylmethyltrimethylammonium chloride, and examples of the amphoteric type include alkylaminopropionate and alkyldimethylbetaine.

The mixing ratio of the above-mentioned cross-linking agent and surfactant is not particularly limited, but preferably the weight of each component in the hydrophilic film-forming agent (coating liquid) having a solid content of 1 to 20% by weight. The ratio is 3 to 100 parts by weight, more preferably 10 to 100 parts by weight of the hydrophilic polymer compound.
70 parts by weight, the surfactant is 1 to 20 parts by weight, more preferably 3 to 10 parts by weight. Further, if necessary, other antifungal agents, antibacterial agents, deodorants, etc. may be added to the coating solution to inhibit hydrophilicity and hydrophilic persistence for the purpose of preventing corrosion of fin materials and generation of unpleasant odor. It is also effective to add it within the range not to do.

The Al alloy fin material according to the present invention is made of Al
The resin coating solution mainly composed of the hydrophilic polymer compound as described above is applied to the surface of the alloy fin material by an arbitrary method such as a dipping method or a coating method, and usually heat-treated at about 150 to 230 ° C to form a film. Can be obtained. The film thickness is
The dry film thickness is generally about 0.5 to 5 μm, preferably about 0.5 to 2 μm, although it varies depending on the conditions of use as a heat exchanger. The Al alloy material may be a flat plate having an arbitrary length, but in view of productivity, it is preferable to continuously process and process the long product wound in a coil shape. At this time, if a chromate film, an organic resin film, a chromium compound-containing organic film or the like is previously formed as a base layer having corrosion resistance on the surface of the Al alloy material, a fin material having both corrosion resistance and hydrophilicity can be obtained. It is preferable because it is possible.

[0025]

EXAMPLES Hereinafter, the constitution and working effects of the present invention will be described more specifically with reference to examples, but the present invention is not limited by the following examples, and is applicable to the gist of the preceding and the following. It is also possible to carry out appropriate modifications within the scope of obtaining, and all of them are included in the technical scope of the present invention.

Example A 0.1 ^t × 100 ^w × 200 ^l mm JIS-A-1100H204 was used as an Al alloy material, and the Al alloy plate was degreased and washed according to a conventional method. The Al alloy plate is used as it is, or a base treatment layer is formed as the first layer,
Various hydrophilic polymer-based hydrophilic treatment agents shown in Tables 2 and 3 were applied thereon, and dried by heating at 200 ° C. for 30 seconds to form a hydrophilic film having a thickness of 1 μm. The test piece of was obtained. The interaction energies of the polymer compound used with one molecule of water are as shown in Table 1.

Each of the obtained test pieces was subjected to various performance evaluation tests to evaluate its usefulness as a fin material for a heat exchanger. In addition, after providing the first undercoat layer on the surface of the aluminum plate that has been degreased and washed in the same manner as above, a surface coating having the configuration shown in Table 4 is formed in the same manner as above, and Comparative Examples 1 to 10 The test piece of 1 was obtained, and the usefulness as a fin material for a heat exchanger was similarly evaluated.

Each test piece was coated with press oil (viscosity of press oil 9.0 cSt / 40 ° C.) → heat-dried (180 ° C. × 7).
min) → submerged in water (24 hours) → dried (180 ° C x 7 mi
n) → Hydrophilicity evaluation was performed in this order, and the hydrophilicity was evaluated by the hydrophilicity after repeating the cycle of running water (running water 5 liters / Hr × 8Hr) → heat drying (80 ° C. × 16Hr) for 8 cycles. evaluated. The hydrophilicity is evaluated by the water repellent state after spraying water, the corrosion resistance is evaluated by the surface state after 10 days of the salt spray test, and the moldability evaluation is evaluated by the presence or absence of cracking in the bent portion when burned. did.

The results are shown in Tables 2-4. In addition, the meanings of the symbols shown in the column of the film constituents in Tables 2 to 4 are as follows. First layer treatment column a: Phosphoric acid chromate coating b: Acrylic resin coating c: Epoxy resin coating d: Acrylic melamine resin coating e: No treatment Crosslinking agent column I: Ammonium zirconium carbonate: Dihydroxybis (lactal) titanium diammonium salt C: Zinc carbonate D: Ethyl acetoacetate aluminum diisopropylate Surfactant column 1: Polyoxyethylene alkylphenyl ether 2: Sodium dodecylbenzene sulfonate 3: Polyoxyethylene / polyoxypropylene copolymer 4: Maleic acid modified poly Oxyethylene

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

As is clear from Tables 2 and 3, the interaction energy with one molecule of water is 1.0 Kcal / m.
The fin material of the present invention having a water-resistant coating mainly composed of a polymer compound of ol or more has excellent hydrophilicity in addition to excellent moldability and corrosion resistance. In contrast, as shown in Table 4, the interaction energy is 1.0K
In each of the comparative examples in which a polymer compound-based coating having a cal / mol of less than 1 was formed, it was found that the hydrophilicity was extremely poor and could not withstand the long-term continuous operation of the heat exchanger.

[0035]

EFFECTS OF THE INVENTION The present invention is constituted as described above, and by incorporating the interaction energy with one molecule of water as a selection criterion of the polymer compound constituting the hydrophilic resin film, it can be stably and reliably A high-performance Al alloy that can form a film with excellent hydrophilicity, and that does not cause pressure loss or reduction in heat exchange efficiency due to the retention of dew condensation water even after continuous operation for a long time. It has become possible to provide a fin material.

Claims (5)

[Claims] 1. In a fin material made of Al or Al alloy having a resinous coating containing a polymer compound as an essential component, the interaction energy (ΔE) per molecule of water obtained by the following formula as the polymer compound. ₀ ) is 1.
A fin material made of Al or an Al alloy having excellent hydrophilicity, which is used by selecting one having a content of 0 Kcal / mol or more. ΔE ₀ = (E _W + E _P −E _WP ) / _{NH 2 O In the} formula, E _W is the energy of the aggregate of water molecules E _P is the energy of the polymer compound model E _P is the energy of the molecule molecule E _WP is the hydrated polymer compound model The molecular energy N _H2O represents the number of hydrated water molecules, respectively. 2. The fin material according to claim 1, wherein the polymer compound is a polymer containing (meth) acrylic acid or vinyl alcohol as a polymerized unit, a cellulosic compound or a mixture thereof. 3. The fin material according to claim 1, wherein the polymer compound-containing resin film contains a metal chelate crosslinking agent. 4. The fin material according to claim 1, wherein the polymer compound-containing resin film contains a surfactant. 5. A corrosion-resistant coating is formed as a base layer of a polymer coating containing a polymer compound.
The fin material according to any one of 1.