JPH0657810B2 - Hydrophilic treatment composition for heat exchanger fin and hydrophilic treatment method using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydrophilic treatment composition for a heat exchanger fin made of aluminum and a hydrophilic treatment method, and more specifically, to water treatment by hydrophilizing an aluminum surface. The present invention relates to a hydrophilic treatment composition for a heat exchanger fin made of aluminum, which keeps a contact angle at 30 ° or less, suppresses or prevents generation of water droplets, and forms a surface excellent in rust prevention, and a hydrophilic treatment method.

(Prior Art) In a heat exchanger of an air conditioner, condensed water generated during cooling forms drops of water to form a bridge of water between fins, which narrows an air passage to increase ventilation resistance, resulting in power loss. Problems such as noise and water droplets may occur. As a measure to prevent such a phenomenon, the surface of an aluminum fin material (hereinafter referred to as a fin material) is made hydrophilic to prevent the occurrence of dew condensation. As such a method, (1)
A method of forming a hydrated aluminum oxide layer on the fin material surface by performing a boehmide treatment known as a surface treatment method of aluminum, (2) a method of applying so-called water glass represented by the general formula mSiO ₂ / nNa ₂ O (For example, JP-B-55-1347 and JP-A-58-126989), (3) paints obtained by mixing silica, water glass, aluminum hydroxide, calcium carbonate, etc. with an organic resin, and surfactants in these compositions. And a method of applying a coating composition (for example, JP-A Nos. 53-125437 and 5-
No. 5-164264, JP-A-59-229197, JP-A-61-225044, etc.), (4) A method of applying a coating material comprising an organic-inorganic (silica) composite resin and a surfactant by the present inventor. (For example, JP-A-59-170
No. 170 etc.) has been put to practical use.

On the other hand, it is known that condensed water generated during cooling corrodes the aluminum fin material, and aluminum hydroxide powder (white powder), which is a corrosion product, scatters, and measures are taken from the standpoint of environmental protection. For example, a chromate treatment agent which is a known surface treatment agent for aluminum, a non-chromate treatment agent using a titanium or zirconium compound, a coating agent including an acrylic resin-melamine resin, and the like have been put into practical use. Since these treated coatings are water repellent, as a method for imparting hydrophilicity to the fin material, a so-called compound coating is used in which an anticorrosive coating such as chromate is formed on the aluminum fin surface and the hydrophilic treatment agent is coated thereon. A layer treatment method has been developed and put to practical use. For example, chromate film-water glass film) JP-A-50-38645 and JP-A-59-13.
No. 078), boehmite film-water glass film (JP-A-62-50477), chromate film-water glass / organic resin film (JP-A-61-225044), chromate film-polyamide resin film (JP-A-62-25044). 61-250495
No.), a chromate film-silica maltolose film (JP-A-61-276697, etc.), a hydrophobic organic resin film-cellulose or a polyvinyl alcohol film (JP-A-6-6).
2-105629).

On the other hand, as a method for surface treatment of a heat exchanger, an aluminum plate is molded and processed to form fins, which are then assembled, and then a surface treatment agent (hydrophilic, rustproof) is dipped, sprayed, showered, etc. There are two methods: a so-called after-coating method of applying the above-mentioned means and a so-called pre-coating method of forming a surface treatment film on an aluminum plate in advance and then press-molding this plate to form a fin material. In the latter, if the inorganic components in the hydrophilic coating layer, such as silica, water glass, alumina, aluminum hydroxide, calcium carbonate, titania, etc. are mixed, the mold used for press molding is significantly worn,
Problems such as poor molding of the fin material, deterioration of corrosion resistance due to destruction of the hydrophilic film, and economic loss due to shortened mold life occur. In recent years, fin materials have been made thinner in order to reduce the size and weight of heat exchangers. For this reason, the molding process is changed from the conventional draw process (overhanging, drawing) to drawless process (ironing). The development of a hydrophilic treatment agent applicable to the latter method has been demanded.

Further, it is known that the air conditioner is in an atmosphere of moderate humidity and temperature and dusts and the like in the room adhere to it, so that microorganisms are easily generated, which causes a bad odor at the start of operation. As a countermeasure against this, it has been proposed to use a film agent mixed with an antibacterial agent and a rust preventive agent (for example, JP-A-58-10051).
No. 58-101717 and 60-503.
97, JP-A-61-168675).

(Problems to be Solved by the Invention) Although the hydrophilization technology for heat exchangers has been put into practical use as illustrated above, any method has not reached the stage where it can sufficiently meet social demands. Not in. For example, the technologies that have been proven as hydrophilic treatment methods have the following problems.

Water glass film: The contact angle with water is relatively low at about 20 ° or less, which is good, but the hydrophilicity deteriorates over time. In addition, the water glass film is hydrolyzed by the adhesion of water to generate an alkali, which causes corrosion (pitting corrosion) of aluminum. In addition, the fine powder is scattered due to the decomposition of the film, and the mold is easily generated by bacteria, and an odor in which both are mixed is generated. Further, in the precoating method, the die wear is remarkable in the fin forming process, and it is not possible to sufficiently deal with it.

Chromate film-Water glass film: Good corrosion resistance to aluminum, but other functions have the same problems as above.

Organic resin-silica film, chromate film-organic resin / silica film: good durability over time in wettability over the entire surface,
The contact angle with water becomes 50 ° or more, and water droplets may be generated between the fins at the start of operation. Also, in the pre-coat method, die wear is remarkable during the fin forming process,
In particular, it cannot fully support the drawless processing method.

Chromate film-polyamide film, acrylic resin film-cellulosic film: The contact angle with water becomes large in terms of durability over time, and water droplets may be generated between the fins as in the above case.

With respect to the above performance problems, the inventors of the present invention have earnestly studied to develop a treatment agent and a treatment system which ensure the corrosion resistance and hydrophilicity of the fin material and further conform to the durability of the die for press molding in the Pile coat method. As a result, the present invention has been completed.

(Means for Solving Problems) According to the present invention, the following hydrophilic treatment composition and a hydrophilic treatment method using the same are proposed.

(A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysis products, and reaction products of natural polysaccharides of natural polysaccharides, derivatives of natural polysaccharides selected from carboxyalkyl derivatives, oxyalkyl derivatives and alkyl derivatives. At least one of them [hereinafter, sometimes abbreviated as “polysaccharide component”]. ] To (C) Ti, Z
A hydrophilic treatment composition for heat exchanger fins made of aluminum, characterized by mixing at least one metal chelate compound of an element selected from r and Al.

2. (A) At least one metal chelate compound of an element selected from Ti, Zr, and Al and (D) a dialkylsulfosuccinic acid ester salt and / or a heat-dissolved product of polyvinyl alcohol and (B) a polysaccharide component. A hydrophilic treatment composition for aluminum heat exchanger fins, which is obtained by mixing an alkylene oxide silane compound.

3. (A) At least one metal chelate compound of an element selected from (C) Ti, Zr, and Al and (E) 2- (4'-thiazolyl) in a heated solution of polyvinyl alcohol and (B) a polysaccharide component. -A hydrophilic treatment composition for heat exchanger fins made of aluminum, which is obtained by mixing a benzimidazole compound.

4. (A) At least one metal chelate compound of an element selected from (C) Ti, Zr, and Al in a heated melt of polyvinyl alcohol and (B) polysaccharide component, (D)
Dialkyl sulfosuccinic acid ester salt and / or alkylene oxide silane compound and (E) 2- (4 '
A thiazolyl) -benzimidazole compound is mixed, and a hydrophilic treatment composition for aluminum heat exchanger fins is characterized.

5. A chromate film is formed on the surface of the aluminum fin material, and (C) Ti, on the heat-dissolved product of (A) polyvinyl alcohol and (B) polysaccharide component, on the chromate film.
At least one metal chelate compound of an element selected from Zr and Al, and optionally (D) a dialkylsulfosuccinic acid ester salt and / or an alkylene oxide silane compound, and optionally (E) 2-
A method for hydrophilizing an aluminum heat exchanger fin material, which comprises coating a hydrophilization composition obtained by mixing a (4'-thiazolyl) -benzimidazole compound.

Hereinafter, the present invention will be described in detail. A known chromate treatment method can be applied to the chromate film used as the lower tank film. That is, a typical alkali salt-chromate method (BV method, M.I.
B. V. Law, E. W. Methods, alloc method, pyrmine method), chromic acid method, chromate method, chromic acid phosphate method and the like, and anhydrous washing coating type treatment method with a composition mainly containing chromium chromate can be used. The coating amount is appropriately adjusted according to the degree of rust prevention of the target material. The purpose of this chromate film is to prevent corrosion as well as to improve the adhesion of the hydrophilic film of the upper layer film at the same time, so the time after formation of the chromate film is not preferable,
After forming the lower layer film, it is preferable to continuously form the upper layer film.

Polyvinyl alcohol (A), which is one of the materials forming the hydrophilic treatment composition in the present invention, plays a major role as a film-forming component and has a large amount of secondary hydroxyl groups in the molecule, so that it has an affinity with water. It has excellent properties, and further exhibits the action of maintaining water resistance and hydrophilic durability by the interaction between the hydroxyl group and other constituent components. A material suitable for this purpose is a polyvinyl alcohol having a saponification degree of 87 to 89% or more, and a particularly preferable material for the present invention is a completely saponified polyvinyl alcohol having a saponification degree of 98% or more. This material has a low solubility in water at room temperature and exhibits favorable properties as a film for a heat exchanger fin material used at room temperature or below. The molecular weight of polyvinyl alcohol is 50.
It is preferably 0 or more, in order to maintain the hydrophilic continuity by the molecular entanglement with the polysaccharide component described below. Further, so-called modified polyvinyl alcohol (for example, copolymer with acrylamide, unsaturated carboxylic acid, sulfonic acid monomer, cationic monomer, unsaturated silane monomer, etc.) reacted with other organic compounds can also be applied.

It is the second component of the hydrophilic treatment composition of the present invention (B).
The polysaccharide component is a component that plays an important role in the durability of hydrophilicity. That is, since the hydroxyl group, the carbonyl group, and the carboxyl group that control the hydrophilicity of the formed film are arranged in the resin main skeleton, there is no selective orientation of these functional groups during the film formation process, and a large amount of hydrophilic groups on the film surface. Is present, and excellent water wettability and a low contact angle with water can be obtained. Materials suitable for such purpose include starches (potatoes, potatoes, tapioca, wheat, corn, etc.), cellulose, and natural polysaccharides such as algin and derivatives of these natural polysaccharides. In the present invention, the natural polysaccharide derivative is
Modified natural polysaccharides such as oxides such as oxidized starch; hydrolysates such as dextrin; reaction products with glycols such as propylene glycol alginate; carboxyalkyl derivatives such as carboxymethyl starch and carboxymethyl cellulose; hydroxymethyl At least one of oxyalkyl derivatives such as starch, hydroxymethyl cellulose, hydroxyethyl cellulose; and alkyl derivatives such as methyl cellulose. Although these polysaccharide components alone form a film, they have insufficient water resistance and cannot be practically used. Therefore, it is used in combination with the above-mentioned component (A), polyvinyl alcohol.

The usage method is as follows.

Since these polysaccharide components are supplied as powder, they are mixed with the polyvinyl alcohol powder of component (A) above,
Dissolve in ~ 100 ° hot water. In this state, both resins interact with each other and intermolecular entanglement occurs,
The hydrophilic functional groups of the component (A) and the component (B) are appropriately distributed in the film, and thus excellent hydrophilic durability is exhibited.

On the other hand, simply by mixing the aqueous solutions of the components (A) and (B), the coating does not have sufficient water resistance and swells, and the component (B) elutes and the desired performance cannot be obtained.

Although the desired performance is achieved by the action mechanism as described above, starch is selected as the preferred polysaccharide component compatible with the present invention. That is, since natural starch does not dissolve in water at room temperature and has a property of being gelatinized and dissolved at a temperature of 80 ° C. or higher, the same action as that of the completely saponified polyvinyl alcohol can be expected.

(C) Titanium (T) which is the third component of the hydrophilic treatment composition
i), zirconium (Zr), and aluminum (A
The metal chelate compound of the element selected from (1) plays a role as a crosslinking agent for improving the water resistance of the film formed from the mixed composition of the component (A) and the component (B) in the present invention. Generally, an amino resin (melamine, benzoguanamine, urea) or an epoxy resin is used as a cross-linking agent for an organic resin containing a hydroxyl group, an amino group, a carboxyl group or the like, but a resin system showing high polarity such as the composition of the present invention is used. When these are used as the curing agent, the desired hydrophilicity cannot be obtained because the curing agent tends to be oriented in the film surface layer during the film formation process. To this end, the present invention provides a metal chelate compound capable of undergoing a substitution reaction between an organic compound coordinated to a metal and a functional group in the component (A) and the component (B) by heating in an aqueous solution. Used.

When the metal element M is a titanium or zirconium element, the metal chelate compound in the present invention is represented by the general formula (R ¹ ) _4-n M (R ² ) _n , and when M is an aluminum element, General formula (R ¹ ) _3-m M
(R ² ) _m alkoxide compound or alkoxyl group-substituted alkoxide compound [wherein n is 2
To 4 and m is an integer of 2 to 3, R ¹ is an ethyl group, an amyl group, a phenyl group, a vinyl group, β- (3.4-).
Epoxycyclohexyl) group, γ-mercaptopropyl group, aminoalkyl group and the like, and R ² is usually an alkoxy group having 1 to 8 carbon atoms (for example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group). Group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, -pentoxy group, isopentoxy group, n-hexoxy group, n-heptoxy group, n-octoxy group, etc.) or the total number of carbon atoms is 2 10 represents an alkoxyl group-substituted alkoxyl group (eg, methoxymethoxy group, methoxyethoxy group, ethoxybutoxy group, butoxypentoxy group, etc.)] to dicarboxylic acids such as maleic acid; ketone alcohols such as diacetone alcohol; acetylacetone Such as diketone; keto such as ethyl acetoacetate Esters; diesters such as ethyl malonate; salicylic acid; phenols having two or more phenolic hydroxyl groups such as catechol and pyrogal; alkanolamines such as triethanolamine, diethanolamine and dimethylaminoalcohol as ligands. It is a coordination compound (complex compound) having 2 or more, preferably 2 to 3 metal alkoxide bonds (including an alkoxyl group-substituted alkoxide bond) bonded together.

With the composition comprising the above three components (A), (B), and (C), the target hydrophilization composition for heat exchanger fins can be obtained, but when the fin pitch is 1.2 mm or less. Is preferably so-called extended wetting with a contact angle with water of 5 degrees or less. For this purpose, as the fourth component,
(D) A dialkyl sulfosuccinic acid ester salt and / or a wetting surfactant of an alkylene oxide silane compound is used. Anionic, cationic, zwitterionic, and nonionic surfactants can be used as long as they have a large wetting action. In the present invention, the stability of the mixed composition and the film are From the viewpoints of maintaining the surface activity of the above (stability of heating action in the film forming process, interaction with other components, etc.), the above two types exhibit the most stable performance. In the present invention, the dialkylsulfosuccinic acid ester salt in the component (D) is a dialkylsulfosuccinic acid ester salt represented by the following formula.

(R ₁ : represents an alkyl group having 1 to 18 carbon atoms. M ₁ : represents an alkali metal such as lithium, sodium or potassium, or represents an ammonium group or an amine.) In the present invention, the alkylene in the component (D). The oxide silane compound is a nonionic alkylene oxide silane compound represented by the following formula.

(X: integer of 5-20, a: integer of 5-20, b: 0
15 integers, y: integers 1 to 8 and R ₂ : carbon number 1 to
6 represents a lower alkyl group of 6) These surfactants can be used alone or in combination. It is presumed that these surfactants are immobilized by hydrogen bonding by the interaction with the functional groups of the components (A) to (C).

In addition, a fungicide can be used as a fifth component in the composition of the present invention. The conditions of the mildew-proofing agent compatible with the present invention include low toxicity from the viewpoint of environmental safety, heat resistance to withstand film forming temperature, insoluble or desolvent in water, and in water-based paint. It can be selected from known aliphatic compounds, aromatic compounds, and inorganic compounds because it is uniformly dispersed and does not impair the hydrophilicity of the formed film.
The most compatible material to the present invention from these antifungal agents include the (E) 2- (4'- thiazolyl) benzimidazole _{(C 10 H 7 N 3 S} ).

The blending ratio of the polyvinyl alcohol of the component (A) and the polysaccharide and / or the polysaccharide derivative of the component (B) in the present invention is 10:90 to 75:% by weight of the solid content.
25, preferably in the range of 50:50 to 25:75.

When the amount of polyvinyl alcohol exceeds 75%, the wettability of the formed film on the front surface is impaired. On the other hand, 90% of polysaccharide resin
If it exceeds, the water resistance of the formed film becomes insufficient and the film tends to swell and dissolve.

The compounding ratio of the metal chelate compound consisting of the elements of titanium, zirconium and aluminum of the component (C) in the present invention is 2 in terms of the solid content weight percentage ratio to the mixture of the components (A) and (B): 98 to 20:80
And preferably in the range of 5:95 to 10:90. When the amount of the metal chelate compound is less than 2%, the amount of residual free hydroxyl groups in the (A) + (B) component composition may be large, so that water resistance and corrosion resistance may not be sufficiently enhanced. If added in excess of 20%, the metal chelate compound itself will preferentially condense and cannot be mixed uniformly, which may make it difficult to form a smooth film, and is also economically disadvantageous. .

The blending ratio of the dialkylsulfosuccinic acid ester salt of the component (D) and the alkylene oxide silane compound in the present invention is a weight percentage ratio of the solid content with respect to the mixture of the components (A) + (B) + (C). 0.5: 99.5 to 10:90, preferably 0.5: 99.5 to 5:95. If the addition amount is 0.5% or less, the expected value of the contact angle of the formed film with water cannot be obtained. On the other hand, if the added amount exceeds 10%, the formed film swells when the formed film comes into contact with the fin material. Problems such as the film falling off from the product and foaming during operation due to water extraction of the surfactant occur.

2- (4'-thiazolyl) which is the component (E) in the present invention
-The compounding ratio of benzimidazole is (A) +
The weight percentage ratio of solids to the mixture of components (B) + (C) is 1:99 to 10:90, preferably 3:97 to 6:94. If the added amount is 1% or less, a sufficient antifungal effect cannot be recognized. If the addition amount is 10% or more, the contact angle of the formed film with water may be large and the corrosion resistance may be deteriorated. However, when importance is attached to the antifungal property, use of 10% or more is also possible.

The method for preparing the hydrophilic treatment composition in the present invention is as follows. First, the component (A) and the component (B) are mixed in a predetermined ratio to obtain an aqueous dispersion having a solid content concentration of 15 to 20% by weight. This mixture is heated under reflux with stirring to above 95 ° C. to dissolve both components. Then, after cooling to room temperature, a predetermined amount of the component (C) is gradually added with stirring to obtain the compound.

Further, depending on the purpose, a predetermined amount of the component (D) may be gradually added to this composition under stirring at room temperature to give a composition. Further, a predetermined amount of the component (E) is gradually added to the composition of (A) + (B) + (C) or the composition of (A) + (B) + (C) + (D) at room temperature under stirring. It can also be an added composition.

The method for forming the hydrophilic coating of the aluminum fin material in the present invention is as follows. That is, the chromate film is formed on an aluminum plate that has been sufficiently degreased. The chromate coating may have a coating composition of either chromium chromate or chromium phosphate. The coating amount is 5 mg / m ² or more, preferably 10 in terms of chromium element.
Is in the range of ˜30 mg / m ² . When the amount is less than 5 mg / m ² , the adhesion of the upper layer film is not sufficient, and when the hydrophilically treated fin material comes into contact with water, the film may swell and fall off. Also, the corrosion resistance is not sufficient. On the other hand, the upper limit is not particularly limited, but in the case of the above-mentioned precoat method, the amount of chromium is 30 in consideration of wear of the die in the press working in the next step.
It is preferably adjusted to be mg / m ² or less. The film forming method can be carried out by a generally known spray, shower, dip, roll or the like.

Then, the aluminum plate or the aluminum heat exchanger core on which the lower layer film of chromate is formed is treated with the above-mentioned hydrophilic treatment composition [(A) + (B) + (C) component system, (A) +
(B) + (C) + (D) component system, (A) + (B) +
(C) + (E) component system, (A) + (B) + (C) +
(D) + (E) component system] to form a hydrophilic film. The coating amount is 0.5 to 5 μm, preferably 1
Is in the range of ~ 3 microns. When the film thickness is 0.5 micron or less, the hydrophilic sustaining effect is not sufficient and water repellency may be exhibited over time. If the film thickness exceeds 5 microns, the heat dissipation efficiency of the fin material may decrease. The film is formed by spraying, showering, dipping, or roll coating.

Then, it is baked and cured to form a tough film. When a short-time baking is desired by a heating method such as hot air, far infrared rays, electromagnetic induction, etc., it is preferable to perform the baking at a metal temperature of 200 ° C. to 250 ° C. for 5 seconds to 50 seconds. If the temperature is 200 ° C or lower, the film is not sufficiently cured and the formed film swells with water. On the other hand, if the temperature exceeds 250 ° C., heat deterioration of the constituents of the film and sublimation of the mildew-proofing agent occur, which is not preferable. If low temperature baking is desired, 1
Baking conditions of 50 ° C. to 180 ° C. and 10 minutes to 30 minutes are preferable. If the conditions are not within this range, the desired performance cannot be obtained.

Thus, a core for a heat exchanger having both corrosion resistance and hydrophilic durability can be prepared, but the present invention is not limited to the combination described above. For example, as a lower layer film, a known aluminum surface treatment method is used. Anodized film, boehmite film, other inorganic film or organic resin film can be used. Further, as the hydrophilic treatment composition for forming the upper layer film, tannic acid, which contributes to the anticorrosiveness of aluminum within the range that does not impair the hydrophilicity, phenolic acid such as gallic acid, and ribbon acids and salts thereof, phytic acid, and phosphonic acid. , A mixture of benzotriazole, imidazole, nitrous acid, chromic acid, etc., a cationic compound such as molybdenum, vanadium, chromium, zinc, nickel, cobalt, copper, iron as a crosslinking accelerator, and an oxygenate compound, or organic coordination The compounds can be mixed. Further, as a material for improving the water retention property of the upper layer film and imparting more hydrophilic durability, silica or alumina compound having a particle diameter of 0.5 micron or less, or a hydrate thereof can be used.

Further, the hydrophilic treatment composition for forming an upper layer film of the present invention should be used as a film agent for preventing dew condensation and preventing snow and ice on molded plastics such as plastic films, molded products, ceramics molded products, and other structures and vessels. You can also

(Example) An example and a comparative example are shown below. These examples are for the purpose of illustrating the present invention in more detail and do not limit the present invention in any way. Parts and% indicate parts by weight and% by weight.

Example 1 90 g of water was charged into a three-necked flask equipped with a thermometer, a stirrer and a condenser, and 90 g of water was added thereto. Then, polyvinyl alcohol powder (manufactured by Denki Kagaku Kogyo KK, trade name "Denka Poval K-"
05 ") 5 g is gradually added at room temperature with stirring. Subsequently, 5 g of starch (Kanto Kagaku Co., Ltd., trade name "Starch, (corn)" is gradually added. This slurry-like mixture is heated to a boiling temperature from 95 ° C.
The solution was retained for a period of time to dissolve, and a transparent to translucent solution was obtained.
Then, this solution was cooled to room temperature, and 0.68 g of g-i-propoxybis (acetylacetonato) titanium (Nippon Soda Co., Ltd., trade name "Titabond-50", solid content 74%) was gradually added and stirred for 15 minutes. A pale yellow suspension composition was obtained.

Example 2 A sulfosuccinic acid ester sodium salt (manufactured by Nippon Emulsifier Co., Ltd.,
Product name "New Call 290M" solid content 75%) 0.4
g was added and stirred for 15 minutes to obtain a suspension composition.

Examples 3 to 10 According to the mixing ratios shown in Table 1, Example 1 and Example 2
Each composition was prepared according to.

Example 11 An aluminum plate (A1050, plate thickness 0.1 mm) was treated with an alkali degreasing agent (manufactured by Nippon CB Chemical Co., Ltd., trade name “Chemic Cleaner 561B”), and then a chromate treatment agent (Nihon Parkerizing Co., Ltd. Under the trade name of "Alchrome 712"), a lower layer film of a chromate film (chrome conversion coating amount: 30 mg / mm ² ) was formed. Then, the composition of Example 1 was applied so as to have a dry film thickness of 1 micron and baked with hot air at 220 ° C. for 30 seconds to form an upper layer film. When the hydrophilicity of this multi-layer coated aluminum plate was examined, as shown in Table 3, excellent wettability and long-lasting hydrophilicity were observed.

Further, the continuous workability was the same as that of the untreated aluminum plate. In addition, the corrosion resistance by salt spray test is 5
No generation of white rust was observed even after 00 hours had elapsed. Further, the adhesion to the aluminum plate was not abnormal at all.

Example 12 A coated plate was prepared under the same conditions as in Example 11, except that the upper layer film was the composition of Example 2. When the hydrophilicity of this coated plate was examined, the contact angle with water was 5 ° C. or less, and the hydrophilic durability was also good. Continuous workability, corrosion resistance,
The coating adhesion was similar to that of Example 1.

Example 13 A coated plate was prepared under the same conditions as in Example 11 except that the upper layer film had the composition of Example 3. When the mold resistance of this coated plate was examined, it showed excellent performance with no generation or adhesion of mold. Hydrophilic persistence, continuous processability, corrosion resistance,
The coating adhesion was similar to that of Example 11.

Example 14 A coated plate was prepared under the same conditions as in Example 11, except that the upper layer film was the composition of Examples 1 to 10. About this coated plate, hydrophilic sustainability, continuous processability, corrosion resistance, coating adhesion,
As a result of a mildew proof test, as shown in Table 3, all showed excellent performance.

Comparative Examples 1 to 2 Example 1 using the composition of the formulation example for comparative example shown in Table 2
A coated plate was prepared in exactly the same manner except that the chromate film as the lower layer film was omitted in Example 1. As a result, as shown in Table 3, the film formed only by the polyvinyl alcohol of Comparative Formulation Example 1 rapidly absorbed and swelled upon contact with water, and the film fell off in running water (Comparative Example 1). The same phenomenon as in Comparative Example 1 was observed in the film formed from the composition of Comparative Formulation Example 3 (Comparative Example 2).

Comparative Examples 3 to 11 Coated plates were prepared in the same manner as in Example 1 using the compositions of the comparative formulation examples shown in Table 2. As a result, as shown in Table 3, the coated plates obtained using Comparative Formulation Example 2 and Comparative Formulation Example 3 were not water wettable over the entire surface and showed water repellency, and water droplets were generated on the surface of the coated plate. (Comparative examples 3-4). When the coated plates of the compositions of Comparative Formulation Examples 4 to 9 were brought into contact with water, the coating quickly absorbed and swelled in water, and the coating fell off in running water (Comparative Examples 5 to 10). The aluminum plate only subjected to the chromate treatment showed water repellency on the surface of the film over time (after 24 hours), and water droplets were generated (Comparative Example 11).

(Effects of the Invention) As described above, the aluminum fin material formed by the composition of the present invention and the surface treatment method using the same retains excellent corrosion resistance due to the chromate film of the lower layer film, and the polyvinyl alcohol of the upper layer film. A hydrophilic film made of a mixture of a water-soluble polysaccharide resin and a polysaccharide resin has a conventional problem of hydrophilic persistence (wetted surface wettability and contact angle with water of 30 ° C.).
Below), continuous molding processability (die abrasion resistance) is maintained, and since it has excellent mold resistance, it exhibits the effect of suppressing odor generation.

Thus, the surface treatment method of the present invention is suitable for energy saving measures and resource saving measures for heat exchangers.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication C09D 129/04 PFM 6904-4J PFN 6904-4J F28F 1/32 H 9141-3L

Claims (5)

[Claims] 1. Natural products selected from (A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysates and reaction products of natural polysaccharides with glycols, carboxyalkyl derivatives, oxyalkyl derivatives and alkyl derivatives. A heat exchange product made of aluminum, which is obtained by mixing at least one kind of a metal chelate compound of an element selected from (C) Ti, Zr and Al with a heated melt with at least one kind of a derivative of a polysaccharide. Hydrophilic treatment composition for container fins. 2. A natural material selected from (A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysates and reaction products of natural polysaccharides with glycols, carboxyalkyl derivatives, oxyalkyl derivatives and alkyl derivatives. (C) At least one metal chelate compound of an element selected from Ti, Zr, and Al, and (D) a dialkylsulfosuccinic acid ester salt and / or an alkylene oxide in a heated melt with at least one of the polysaccharide derivatives. A hydrophilic treatment composition for aluminum heat exchanger fins, which is obtained by mixing a silane compound. 3. A natural product selected from (A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysates and reaction products of natural polysaccharides with glycols, carboxyalkyl derivatives, oxyalkyl derivatives and alkyl derivatives. At least one metal chelate compound of an element selected from (C) Ti, Zr, and Al and (E) 2− in a heated melt with at least one of the polysaccharide derivatives.
A hydrophilic treatment composition for aluminum heat exchanger fins, which is obtained by mixing a (4'-thiazolyl) -benzimidazole compound. 4. A natural material selected from (A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysates and reaction products of natural polysaccharides with glycols, carboxyalkyl derivatives, oxyalkyl derivatives and alkyl derivatives. (C) at least one metal chelate compound of an element selected from Ti, Zr, and Al, and (D) a dialkylsulfosuccinic acid ester salt and / or an alkylene oxide in a heated melt with at least one of the polysaccharide derivatives. A hydrophilic treatment composition for aluminum heat exchanger fins, comprising a mixture of a silane compound and (E) 2- (4'-thiazolyl) -benzimidazole compound. 5. A chromate film is formed on the surface of an aluminum fin material, and (A) polyvinyl alcohol and (B) natural polysaccharides and oxides, hydrolysates and glycols of natural polysaccharides are formed on the chromate film. (C) a metal of an element selected from Ti, Zr, and Al in a heated melt with at least one of the natural polysaccharide derivatives selected from the reaction product of (1), a carboxyalkyl derivative, an oxyalkyl derivative, and an alkyl derivative. At least one chelate compound, and optionally (D) dialkylsulfosuccinic acid ester salt and / or alkylene oxide silane compound, and optionally (E) 2- (4'-
A method for hydrophilizing an aluminum heat exchanger fin material, which comprises coating a hydrophilizing composition obtained by mixing a thiazolyl) -benzimidazole compound.