JP2518654B2 - Heat exchange medium material and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to a heat exchange medium material such as a fin made of aluminum or an aluminum alloy used for a heat exchanger of an automobile or a cooling / heating device for home electric appliances, and a manufacturing method thereof.

[Prior art and its problems]

A heat exchange medium material made of aluminum or an aluminum alloy (hereinafter, simply referred to as an aluminum alloy) usually has a surface on which a film of organic, inorganic, or a composite system thereof having good wettability is formed. Then, the fin material for heat exchange medium is press-molded to form fins. After that, it is incorporated into the heat exchanger through a step of degreasing a lubricating oil such as a press oil adhered to the fin surface or the like in a press working step with an organic solvent or a neutral or weak alkaline detergent aqueous solution. In such a heat exchanger, the fin pitch of the heat exchanger tends to be reduced in recent years in order to improve the heat exchange efficiency and reduce the size thereof. In such a case, in the evaporator, the fin pitch of moisture in the atmosphere is reduced. Condensation of air causes an increase in ventilation resistance and dry-humidity ratio, noise generation, and blowout of condensed water into the room.In addition, defrosting energy increases outdoors in winter, so the fin surface is wettable. Also, good oil stain resistance is becoming extremely important. Therefore, the present inventor has already proposed various techniques (for example, Japanese Patent Publication No. 60-1558) as a method for solving these problems. That is, an aluminum alloy thin plate (usually 0.05 to 0.2 mm
After the surface is treated with sodium hypochlorite or the like to form a hydrated oxide film on the surface, silicon is applied to the film by dipping treatment with, for example, an alkali silicate (water glass) or the like. By interposing a compound, a heat exchange medium material excellent in moldability, water wettability, corrosion resistance and the like is industrially mass-produced. However, even when these heat exchange medium materials are actually assembled and used as a heat exchanger, they are not without problems, and for example, one of those problems is that the heat exchanger medium is When contaminants are easily adsorbed, so-called "cement odor", "mold odor", and other problems that produce an extremely weak offensive odor and deterioration of fin pitting corrosion resistance in severe corrosive environments Such problems are being pointed out.

DISCLOSURE OF THE INVENTION

The present inventor, as a result of earnestly pushing forward the research on the above problems, a silicon compound of about 0.01 to 0.04 g / m ² in terms of silicon and a phosphorus compound of about 0.005 to 0.03 g / m ^{2 in} terms of phosphorus are selected. On the surface of the aluminum alloy material on which a hydrated oxide film having a thickness of about 0.4 to 0.6 g / m ² is provided,
The heat exchange medium material provided with a 0.8 g / m ² thick hydrophilic resin coating film does not have a strange odor such as so-called "moldy odor", and has excellent wettability and durability (persistence) of wettability. In addition, they have found that they have excellent white rust resistance and pitting corrosion resistance, and also have excellent press workability, and have completed the present invention. Incidentally, the hydrated oxide film formed on the surface of the aluminum alloy is preferably formed by treatment with a neutral or basic aqueous solution, for example, a boehmite-based film formed by immersion in boiling pure water. Examples include boehmite-based coatings treated with a pure water-based solution adjusted to pH 9 to 12 with various basic substances such as triethanolamine, ammonia or caustic soda. In addition, in the solution for forming the hydrated oxide film as described above,
For example, when an oxidizing agent such as hypohalite, halohalite, halogenate, or peroxoborate is added, a product having further improved press workability can be obtained. And what is extremely important is to keep the thickness of this hydrated oxide film at about 0.4 to 0.6 g / m ² . That is, when the thickness of the hydrated oxide film is too thin, the adhesion of the hydrated oxide film and the coating film provided on the hydrated oxide film becomes weak, and for example, the coating film is likely to peel off after pressing on the fin. However, if the hydrated oxide film is too thick, cracks may be observed on the surface of the hydrated oxide film after press working on the fins, or water may not be used. The coating film provided on the surface of the Japanese oxide film becomes easy to peel off, leading to a decrease in corrosion resistance.
Moreover, the "moldy smell" is now felt. In addition, the above-mentioned hydrated oxide film has a silicon equivalent of about
0.01 to 0.4 g / m ² of a silicon compound is intercalated, which hydrates a silicate-containing solution such as an aqueous solution or suspension of water glass, sodium silicate, potassium silicate, silica sol, etc. It can be carried out by treating the aluminum alloy surface on which the oxide film is formed with an appropriate means such as spraying or dipping. The silicate concentration in the silicate-containing solution used is, for example, about 0.5 to 10%, preferably about 0.5 to 5%. And what is important in the treatment with this silicate-containing solution is that the amount of the silicon compound that intervenes in the hydrated oxide film is
It is about 0.01 to 0.04 g / m ^{2 in} terms of silicon. That is, if the amount of the silicon compound to intervene in the hydrated oxide film is too small, the coating film provided on the hydrated oxide film is likely to peel off when placed under severe environmental conditions after pressing. Corrosion resistance tends to be poor, and durability of water wetting tends to be poor. Conversely, if the amount of silicon compound is too large, there is no problem in terms of durability of water wetting, but a "moldy odor" is felt. This is because the coating film provided on the hydrated oxide film tends to peel off and the corrosion resistance tends to deteriorate when exposed and exposed to severe environmental conditions after pressing. Further, the hydrated oxide film as described above has a phosphorus conversion of about 0.
005 ~ 0.03g / m ² of the phosphorus-based compound is interposed, which is treated with an aqueous solution containing the phosphorus-based compound,
It can be easily carried out by drying. For example, the phosphorus compound is dissolved in water such as deionized water, tap water or industrial water so that the concentration is 50 ppm or more, preferably about 1 to 20%, and the pH is 2 to 12, preferably p.
It can be easily formed by using an aqueous solution of a phosphorus-based compound adjusted to H6 to 8 at a temperature of 10 to 100 ° C for 1 to 10 minutes, preferably 5 to 20 seconds, by applying, coating or showering means. . The pH of this aqueous solution can be adjusted by using phosphorus compounds.
Considering pH, phosphoric acid, citric acid, acetic acid, NaOH, KO
It may be performed using H, Ca (OH) ₂ , triethanolamine, ammonia, or the like. Then, the phosphorus compound to be present on the film of the hydrated oxide film system by treating with the solution containing the phosphorus compound, from the viewpoint of corrosion resistance and coating adhesion, is converted to about 0.005 to 0.03 g / phosphorus. It was desired to be m ² . That is, when the content is 0.03 g / m ² or more, the adhesion of the coating film deteriorates and the coating film peels off during press working. On the other hand, if it is 0.005 g / m ² or less, the corrosion resistance of the fin after actual use is poor. Examples of the phosphorus compound include hypophosphite, orthophosphite, pyrophosphate, metaphosphite, hypophosphite, orthophosphate, metaphosphate, tripolyphosphate, tetrapolyphosphate. One or more water-soluble salts such as acid salts and inorganic phosphates such as pyrophosphate can be used. In the case of the treatment with the phosphorus compound solution, it is more preferable to treat with a solution containing a small amount of a surfactant such as 0.1 to 2%. That is, when not only the phosphorus compound but also the surfactant is interposed in the hydrated oxide film,
It has been found that the adhesion of the phosphorus compound to the hydrated oxide film is improved and becomes more desirable. And, the hydrophilic resin coating film is provided on the hydrated oxide film in which the silicon compound and the phosphorus compound are interposed as described above, and the hydrophilic resin coating film has a thickness of about 0.1 to 0.8 g. It is important to keep / m ² . That is, if the thickness of the coating film is too thin, although there is no problem in the persistence of water wetting and press workability, "mold odor" is clearly felt, and the corrosion resistance tends to decrease, on the contrary, This is because if the thickness of the coating film is too thick, the problems of "mold odor" and corrosion resistance will disappear, but the sustainability of water wetting will deteriorate. Incidentally, the hydrophilic resin coating film is an acrylic ester type, an alkyd type, an acrylic alkyd type, an acrylic modified cellulose type, a cellulose type, a polyester type, an epoxy type,
1 to various hydrophilic resins such as polyamino type and polyamide type
It can be constituted by applying a coating solution of an aqueous solution or an aqueous dispersion solution containing 20% by weight, preferably 2 to 10% by weight. Then, in a coating material containing such a hydrophilic resin, about 0.1
If a surfactant is contained in an amount of about 5%, the adhesion between the hydrated oxide film and the hydrophilic coating film will be improved, and the water wettability and the durability of water wettability will be improved. Is preferred. Further, the present invention is a hydrated oxide film formation for forming a hydrated oxide film having a thickness of about 0.4 to 0.6 g / m ² by treating a cold rolled material of aluminum or aluminum alloy with a neutral or basic aqueous solution. Process and the hydrated oxide film formed in this hydrated oxide film forming process is treated with a silicate-containing solution to interpose about 0.01 to 0.04 g / m ² of silicon compound in terms of silicon on the surface of the hydrated oxide film. A silicate-containing solution treatment step to be performed, and the hydrated oxide film formed in the hydrated oxide film forming step is treated with a phosphorus-containing compound-containing solution to convert the hydrated oxide film surface to about 0.005 to 0.03 g / phosphorus in terms of phosphorus. A phosphorus compound-containing solution treatment step in which a phosphorus compound of m ² is interposed, an annealing step of temper annealing this after passing through the hydrated oxide film forming step, and applying a hydrophilic resin coating after this annealing step. , Display a coating film whose thickness after baking and drying is about 0.1 to 0.8 g / m ^2. It is intended to provide a method for producing a heat exchange medium material, which has a coating film forming step provided on a surface and a molding processing step of subjecting the coating film forming step to predetermined molding processing. The cold-rolled aluminum alloy material means a material that has not been substantially annealed after cold-rolling, and has, for example, a surface without oil seizure. Then, as a pretreatment of the step of forming a hydrated oxide film on the surface of the cold-rolled material of the aluminum alloy, it is usually degreased with a neutral or alkaline aqueous solution, but if the rolling oil can be removed. The content of the pretreatment as described above is not limited, and for example, pickling or hot water washing may be performed. Further, the aluminum alloy provided with a hydrated oxide film with a silicon compound and a phosphorus compound interposed is temper-annealed. This temper-annealing step is performed after cold rolling, and The reason why the formation of the Japanese oxide film is performed is as follows. That is, if the temper annealing is performed before the formation of the hydrated oxide film, the residual oil component is seized, the hydrated oxide film is difficult to be formed well, and the coating film adhesion tends to decrease. This is because no inconvenience occurred even when H ₂ n material, H ₃ n material or 0 material was subjected to temper annealing. The heat treatment temperature is about 200 to 500 ° C. and the heat treatment time is from several seconds to about 20 hours.

Example 1 JIS1200, H18 aluminum alloy material was degreased by weak alkaline etching, and then sodium hypochlorite aqueous solution (NaOCl concentration 2
00ppm, pH 10.5) at a temperature of about 85 ℃, about 0.6g /
Form a hydrated oxide film of m ² . Then, it is immersed in a 1.5% water glass solution (pH 11.4) at a temperature of about 60 ° C., and a shower water washing step is performed to provide a silicon compound of about 0.025 g / m ^{2 in} terms of silicon on the surface of the aluminum alloy material. After that, under the condition of 25 to 30 ° C, 12% sodium tripolyphosphate and 0.5% polyoxyethylene nonylphenyl ether (HLB number 14) aqueous solution are applied, and hot air drying is carried out at 150 ° C for 10 seconds to convert it to approximately phosphorus. An inorganic phosphate of 0.015 g / m ² and a nonionic surfactant are interposed on the surface of the hydrated oxide film treated with water glass. Then, this is heated and annealed in an atmospheric furnace at 260 ° C. to make it equivalent to H26 material. Thereafter, on the surface of the aluminum alloy thin plate, a polyamide-based water-based paint containing a nonionic and anionic surfactant (manufactured by Nippon Paint Co., Ltd., trade name NP Alcoat 11
2. Resin solid content 20%) was applied by a roll coat of about 3 g / m ^{2 and} dried by heating at 230 ° C. for 60 seconds to give a coating film having an application amount of 0.6 g / m ^{2 on} the surface of the aluminum alloy thin plate. Then, the pre-coated fin material was draw-pressed to form fins. Then, after degreasing with a trichloroethylene solvent at 80 ° C. for 1 minute, this was assembled into a heat exchanger.

Example 2 After washing the aluminum alloy material after degreasing with weak alkaline etching in Example 1, washing with water, triethanolamine 1.
The product is immersed in an aqueous solution containing 5% and having a pH of 10.0 at a temperature of 90 ° C for boehmite treatment to form a hydrated oxide film of about 0.4 g / m ² thickness on the surface of the aluminum alloy material. p
It is immersed in a 10% water glass solution adjusted to H12.8 at a temperature of about 85 ° C, then washed with shower water, and a silicon compound of about 0.04 g / m ^{2 in} terms of silicon is interposed on the surface.
The to 30 ° C. tripolyphosphate aqueous sodium concentration of 15% at a temperature of coated, and subjected to hot air drying for 10 seconds at 0.99 ° C., the inorganic phosphate from about 0.03 g / m ² are water glass treated with phosphorus terms Intercalated on the surface of the hydrated oxide film. Then, this is heated and annealed in an atmospheric furnace at 260 ° C. to make it equivalent to H26 material. Thereafter, on the surface of the aluminum alloy thin plate, an acrylic-modified cellulose-based water-based paint (manufactured by Nippon Paint Co., Ltd., trade name NP Alcoat 150, resin solid content 15%) was applied by a roll coat of about 8 g / m ² at 230 ° C., 62 Heat dry for a second,
A coating film having a coating amount of 0.3 g / m ^{2 was} applied to the surface of the aluminum alloy thin plate. Then, this pre-coated fin material was subjected to drawless press working to form fins. Then, after degreasing with a trichloroethylene solvent at 80 ° C. for 1 minute, this was assembled into a heat exchanger.

Comparative Example 1 A heat exchanger was obtained through the same steps as in Example 1, except that the coating amount of the polyamide-based water-based paint after drying was 0.04 g / m ² .

Comparative Example 2 A heat exchanger was obtained through the same steps as in Example 1, except that the coating amount of the polyamide-based water-based paint after drying was about 1.0 g / m ² .

[Comparative Example 3] A heat exchanger was obtained through the same steps as in Example 1, except that the amount of the hydrated oxide film was 0.9 g / m ² .

Comparative Example 4 A heat exchanger was obtained through the same steps as in Example 1, except that the amount of the hydrated oxide film was set to about 0.3 g / m ² .

Comparative Example 5 A heat exchanger was obtained through the same steps as in Example 1, except that the silicon compound was not interposed on the surface of the hydrated oxide film.

Comparative Example 6 A heat exchanger was obtained through the same steps except that the silicon compound on the surface of the hydrated oxide film was changed to about 0.05 g / m ^{2 in} terms of silicon in Example 1.

【Characteristic】

Regarding the heat exchanger of each example obtained as described above,
Initial water wettability (wind speed 1m / see, ventilation resistance dry / wet ratio in 30 ° C, 60% RH), water wettability (water wettability of fin surface after immersion in running water for 500 hours), so-called "mold odor" , Etc., corrosion resistance (presence or absence of pitting corrosion after 1000 hours in a salt spray test according to JIS Z 2371) and press workability on fins (water on the fin surface after pressing fin material) The conditions of the Japanese oxide film and the coating film) were examined, and the results are shown in the table. According to this, in the example, since the dry / wet ratio shows a value within the range of 1 to 1.2, it is excellent in water wettability and water wettability, and the heat exchange efficiency is high. Can be seen to be excellent. In addition, no strange odor such as so-called "moldy odor" is observed. This means that in a cooler or the like used at home, this is unlikely to be a mold source, and will not adversely affect health. In particular, as the number of households made of reinforced concrete that prevent moisture from escaping increases, the number of patients with asthma who have mold as an allergen is increasing, but it is extremely significant that such mold is unlikely to occur. It is also extremely excellent in corrosion resistance and press workability. On the other hand, the coating film on the hydrated oxide film is about 0.04
If it is too thin, such as g / m ^2, as shown in Comparative Example 1, water wettability and press workability are good, but
There are drawbacks such as "moldy odor" being recognized and poor corrosion resistance. On the contrary, when the coating film provided on the hydrated oxide film is too thick as 1 g / m ^2, as shown in Comparative Example 2, no “moldy odor” is observed and the corrosion resistance is high. Although it is good, it has a large dry / wet ratio of 1.35, and has a drawback of poor durability against water. That is, comparing Comparative Examples 1 and 2 with this Example, in the case of Comparative Example, "moldy odor" was recognized when the water wetting continuity was improved, and "moldy odor" was removed. In this case, either of the drawbacks such as the poor wettability persists, whereas the characteristics of the present example are good. Further, when the thickness of the hydrated oxide film was increased to about 0.9 g / m ^2, as shown in Comparative Example 3, although wettability was improved, a “moldy odor” was felt, At the same time, the corrosion resistance decreases, and the press workability also deteriorates. On the contrary, if the hydrated oxide film is too thin, such as about 0.3 g / m ^{2, the} hydrated oxide film and the coating film formed on the surface of the aluminum alloy will be peeled off by pressing in this case. It will not be used in practice. That is, comparing Comparative Examples 3 and 4 with the present Example, in Comparative Example 3, even if the water wettability was good, “moldy odor” was felt, and as in Comparative Example 1, Although the drawbacks have not been solved, the characteristics of the present embodiment are good. When no silicon compound is present on the surface of the hydrated oxide film, as shown in Comparative Example 5, "moldy smell"
Although it is not observed, the water-wettability is poor, and the corrosion resistance and press workability are also poor. On the contrary, when the amount of the silicon compound intercalated on the surface of the hydrated oxide film is too large, as shown in Comparative Example 6, the wettability is improved, but a "moldy odor" is felt. There is. That is, even in this case, when the water wettability was improved as in Comparative Examples 1 and 2, "mold odor" was observed, and conversely, when the "mold odor" was removed, While either defect such as poor water wettability appears, the properties of the present embodiment are good.

Claims (2)

(57) [Claims] 1. A about 0.4 to 0.6 g / m ² thick the phosphorus compound is interposed about 0.005~0.03g / m ² in silicon compound of from about 0.01-0.04 / m ² of silicon in terms and phosphorus in terms of water A heat exchange medium material characterized in that a hydrophilic resin coating film having a thickness of about 0.1 to 0.8 g / m ² is provided on the surface of an aluminum or aluminum alloy material provided with a Japanese oxide film on the surface. 2. A cold-rolled material of aluminum or aluminum alloy is treated with a neutral or basic aqueous solution to apply a surface treatment.
A hydrated oxide film forming step for forming a hydrated oxide film having a thickness of 0.4 to 0.6 g / m ² and a hydrated oxide film formed in this hydrated oxide film forming step are treated with a silicate-containing solution to obtain water. A silicate-containing solution treatment step of interposing a silicon compound of about 0.01 to 0.04 g / m ^{2 in} terms of silicon on the surface of the Japanese oxide film, and the hydrated oxide film formed in the hydrated oxide film forming step is a phosphorus-based compound. Treated with the solution containing about 0.
005 ~ 0.03g / m ² phosphorus compound-containing solution treatment step of interposing a phosphorus compound, an annealing step of temper annealing it after the hydrated oxide film forming step, and a hydrophilic property after this annealing step A coating process in which a resin coating is applied and a coating film having a thickness after baking and drying of about 0.1 to 0.8 g / m ² is provided on the surface, and a predetermined forming process is performed after this coating film forming process A method of manufacturing a heat exchange medium material, comprising the steps of: