JPS61222629A - Manufacture of material and machine for heat exchanger - Google Patents

Abstract

PURPOSE:To prevent adsorption of a press oil during washing of a material and to get a good hydrophilic property by forming an inorganic film having a good wettability on the surface of Al material and including an inorganic phosphoric compound in the surface of the inorganic film. CONSTITUTION:After the inorganic film having a good wettability is formed on the surface of Al or Al alloy material, the inorganic film is treated by an inorganic phosphoric acid solution and is dried to make the compound to be included in the surface of the inorganic film. Then, a specified forming work is performed and formed components are assembled. Thus, a heat exchanger is manufactured with a good working efficiency and at a less expense.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat exchanger material and a method for manufacturing a heat exchanger used, for example, in heat exchangers for automobiles or cooling/heating equipment for home appliances.

[Prior art and its problems]

A heat exchanger made of aluminum or an aluminum alloy (hereinafter simply referred to as aluminum) has, for example, a hydrophilic (good water wettability) film formed of an inorganic, organic, or composite material on the surface of the aluminum material. The heat exchanger fins are formed by pressing aluminum material.
After that, the press oil that adheres to the surface during the press processing process is degreased with a neutral or weakly alkaline detergent aqueous solution or a non-aqueous solvent (e.g. perchloroethylene, trichlorethylene, trichloroethane), and then this is assembled. . By the way, in order to improve the heat exchange efficiency and make the heat exchanger more compact, the fin pitch tends to decrease. It is important to improve the water wettability of the fin surface to avoid problems such as increased defrosting, generation of noise, and condensed water being blown into the room, and an increase in defrosting energy outdoors in the winter. is extremely important.

The present inventor has developed a technical means that satisfies the above points and previously proposed it (Japanese Patent Application Laid-open No. 106396/1983), but even with this technical means, some problems remain. In other words, the pre-coated fin material proposed in JP-A-58-106396 was press-molded, washed with an organic solvent such as trichlorethylene, and assembled into an evaporator. It has been found that it is difficult to obtain good hydrophilicity depending on the properties.

[Disclosure of the invention]

The present inventor conducted research on the above-mentioned problems.

The reason for this problem is that the porosity of the inorganic film on the surface of the aluminum material makes it insufficient to remove the press oil that has penetrated and adsorbed into the micropores during cleaning, and as a result, the good hydrophilicity of the inorganic film itself is impaired. As a result of further research, we found that an inorganic film with good water wettability was formed on the surface of the aluminum material, and an inorganic phosphoric acid compound was interposed on the surface of the inorganic film. It has been found that the hydrophilicity of the film itself is not inhibited regardless of the washing conditions, the form and properties of the film, and the above-mentioned problems are almost completely solved.

Inorganic films with good water wettability are, for example, anodized films, boehmite films, films treated with boehmite or silicate after anodization, films treated with silica sol, and silicate films after chromate treatment. treated film, silicate coated film, film with silica sol aqueous solution,
Alternatively, there is an oxide film produced in a bath containing an oxidizing agent as disclosed in JP-A-58-106397, and these inorganic films have a pore diameter of approximately 100 to 200λ in the case of an anodic oxide film, for example. In the case of a boehmite-based film, the pore size is approximately 500 to 1000 pores, and in the case of a silicate-treated film, the pore size is approximately 3000 to 100 000 mm.
It is particularly desirable that the inorganic coating is porous with micropores having a pore diameter of A, and that the thickness of the inorganic coating is about 2 to 11011 I/-.

Further, the i-free compound interposed on the surface of the inorganic film is formed by, for example, treating with a solution containing an inorganic phosphate and drying.

The above treatment can be carried out by, for example, dissolving phosphates such as Ha and Ca in water such as deionized water, tap water, industrial water, etc., and using this phosphate aqueous solution by dipping, coating, or showering. You can do it by etc.

In addition, examples of inorganic phosphates include hypophosphorous acid salts, orthophosphites, pyrophosphites, metaphosphites, hypophosphates, orthophosphates, metaphosphates, One or more suitable compounds such as monoperoxyphosphate, peroxydiphosphate, tripolyphosphate, tetrapolyphosphate, and pyrophosphate 2 are used.

At this time, the inorganic phosphate solution contains approximately 50 ppm.
~ solubility limit, preferably at a concentration of about 1 to 5911, at a temperature of about 10°C to boiling temperature, preferably about 20 to
At 80°C, for about 1 second to 10 minutes, preferably about 5 to 20 minutes.
The reaction may be carried out at a pH of about 2 to 12, preferably about 4 to 9, more preferably about 6 to 8. For pH adjustment,
Phosphoric acid, N
This may be carried out by adding a basic compound such as aOH, KOH, Ca(OH), etc.

For example, the inorganic phosphoric acid compound layer formed on the surface of the inorganic film layer by the above-mentioned treatment needs to have a certain thickness in order for the inorganic phosphoric acid compound layer to have a large effect. It is desirable that this thickness is, for example, about 1 η/m or more, more preferably about 5 to 150 mg/m, in terms of the amount of P deposited.

In order to make a heat exchanger using an inorganic film with good water wettability and an inorganic phosphoric acid compound layer formed on the surface of the inorganic film as described above, the pre-coated aluminum material is used. Drawless press processing, draw press processing, other appropriate processing such as punching or flaring is performed to form the fin into a predetermined shape, and after this press processing, the attached press oil is removed by neutral or weak alkaline detergent aqueous solution, trichlorethylene, etc. can be made by washing away with an organic solvent.

Since the heat exchanger manufactured in this way uses a material with an inorganic phosphate compound layer on the surface of the inorganic film, the polarity of the micropore surface is modified and the press oil is It is difficult to absorb during cleaning,
The water wettability of the inorganic film surface has not decreased significantly,
Therefore, it has good heat exchange efficiency. Further, since a complicated process for removing press oil is not required, a heat exchanger can be provided with high manufacturing efficiency and at low cost.

[Example 1] JIS 1200-H267 aluminum material (width 3 Q
Qmm, length 8000 m, thickness 0.1151 mm
) to a sodium hypochlorite aqueous solution (N1pl concentration 2
00f) pm 1 pH 10,5) at a temperature of about 85°C, then I) immersion in a 1.5% water glass solution of H11,4 at a temperature of about 60°C, followed by a shower rinsing step. Through this process, an inorganic oxide film having a thickness of about 71n9/dm and having good water wettability is formed on the surface.

Next, a sodium tripolyphosphate aqueous solution with a temperature of 25 to 30°C and a concentration of 1000 pI)m was applied to the aluminum material surface on which the oxide film was formed, and then hot air drying was performed at 150°C for 10 seconds to determine the amount of P attached. Then, the aluminum material coated with the inorganic phosphoric acid compound was subjected to drawless pressing mainly ironing to produce fins, and then degreased with trichlorethylene (85 °C for 1 minute) and assemble into a heat exchanger.

[Example 2] After forming a similar oxide film through a process similar to the step of forming an inorganic oxide film with good water wettability in Example 1, potassium pyrophosphate and An aqueous solution containing 3000 ppm of potassium tetrapolyphosphate is applied, followed by hot air drying at 150° C. for 10 seconds to deposit an inorganic phosphoric acid compound with a thickness of 20 mF'm as the amount of P deposited.

Then, the aluminum material coated with the inorganic phosphoric acid compound is subjected to drawless press processing to produce fins, and then degreased with trichlorethylene (50℃-30℃-7
0° C. for 1 minute each) and assembled into a heat exchanger.

[Example 3] The same aluminum material as in Example 1 was etched with a weak alkali, washed with water and dried, and then treated with a sodium silicate aqueous solution (Si
O2/Na20=5, SiO□ concentration s 5g/l) was applied by dipping at 60°C for 1 minute, and then dried at 200°C for 60 seconds to form an inorganic oxide film with good water wettability of approximately 8 Wvdm thickness on the surface. do.

Next, an aqueous solution containing 2000 ppm each of sodium hypophosphite, sodium orthophosphate, and sodium tetrapolyphosphate was applied to the surface of the aluminum material on which the oxide film was formed, and then hot air was dried at 120°C for 20 seconds. , an inorganic phosphoric acid compound with a thickness of 501'V/m'' is deposited as a P deposition amount.

Then, the aluminum material coated with the inorganic phosphoric acid compound is subjected to drawless press processing to produce fins, and then degreased with trichlorethylene (60℃-30℃-8
0° C. for 1 minute each) and assembled into a heat exchanger.

[Practice/Example 4] The same aluminum material as in Example 1 was etched with a weak alkali, washed with water and dried, and then treated with 0.0% triethanolamine.
Boehmite treatment is performed by immersing the material in an aqueous solution containing 5'16 at 90° C. for 60 seconds to form an inorganic oxide film with a thickness of about 4119/di and good water wettability on the surface.

Next, 30001)I)m each of sodium hypophosphate, calcium pyrophosphite, potassium monoperoxyphosphate, sodium peroxydiphosphate, sodium orthophosphate, and sodium metaphosphate was applied to the aluminum material surface on which the oxide film was formed. After applying the containing aqueous solution, hot air drying is performed at 80° C. for 20 seconds to deposit an inorganic phosphoric acid compound having a thickness of 80111977F+′ as the amount of P deposited.

Then, the aluminum material coated with the inorganic phosphoric acid compound is subjected to drawless press processing to produce fins, and then degreased with trichlorethylene (40°C - 30°C - paper, 1 minute each), and then heat exchanger Assemble to.

[Example 5] JIS 1050-H22 aluminum material (width 119
□mm, length 5000m, thickness 0.120mm) was coated with a 2% chromate aqueous solution (Alodine≠12 manufactured by Nippon Paint Co., Ltd.).
00) at 35°C for 20 seconds, then 2
It is immersed in a Tisilica sol aqueous solution at 35°C for 2 minutes to form an inorganic film with good water wettability on the surface with a thickness of about 5 m9/di.

Next, after applying an aqueous solution containing 250,001 pm each of sodium pyrophosphate and sodium tripolyphosphate to the surface of the aluminum material on which the film was formed, 25
After drying with hot air for 10 seconds at 0°C, the amount of P attached was determined as follows:
Deposit 150 mg/m'' thick inorganic phosphoric acid compound.

Then, the aluminum material coated with the inorganic phosphoric acid compound was subjected to draw press processing to produce fins, and then degreased with trichloroethane (50°C - 30°C - 70°C,
1 min each) and assemble into the heat exchanger.

[Comparative Examples 1 to 5] Heat exchangers were obtained in the same manner as in Examples 1 to 5, except that the treatment with the inorganic phosphate solution was omitted.

[Comparative Example 6] A heat exchanger is obtained by carrying out the same procedure as in Example 1 but omitting the oxide film forming step.

[Comparative Example 7] A heat exchanger was obtained by carrying out the same procedure as in Example 1 using a solution of 5 organic phosphate esters (tridodecyl phosphate) instead of the inorganic phosphate solution.

〔Characteristic〕

The water wettability (hydrophilic contact angle) of the heat exchanger fins obtained as described above was examined as shown in the table.

Table As can be seen from this table, the product of this example has good water wettability, especially even if degreasing treatment is performed after pressing. As can be seen from the value of the hydrophilic contact angle after 500 hours of washing with running water, the durability of water wettability was also good, whereas Comparative Example 1, in which treatment with an inorganic phosphate solution was omitted,
~5. In Comparative Example 6 in which the oxide film forming step was omitted, and in Comparative Example 7 in which the phosphate was organic, even though the phosphate treatment was performed, water wetness occurred due to the degreasing treatment performed after pressing and spraying. In addition, the durability of this water wettability is also poor.

Claims (1)

[Scope of Claims] 1. A heat exchanger characterized in that an inorganic film with good water wettability is formed on the surface of an aluminum or aluminum alloy material, and an inorganic phosphoric acid compound is interposed on the surface of the inorganic film. material. 2. After forming an inorganic film with good water wettability on the surface of aluminum or aluminum alloy material, the inorganic film is treated with an inorganic phosphate solution and dried to form an inorganic phosphate compound on the surface of the inorganic film. A method of manufacturing a heat exchanger, which comprises: interposing the heat exchanger, then performing a predetermined molding process, and assembling the molded product.