JPH02989B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a method for manufacturing aluminum fins for heat exchangers. In this specification, aluminum includes aluminum and aluminum alloys. 2. Description of the Related Art In general, in a heat exchanger, particularly an evaporator of an air conditioner, water droplets adhere to the surface of the fin because the surface temperature of the fin is below the dew point of the atmosphere. Due to the adhesion of such water droplets, ventilation resistance increases, the air volume decreases, and heat exchange efficiency decreases. This becomes especially noticeable when the fin pitch is narrowed to improve the performance and downsize the heat exchanger. Heat exchange efficiency is greatly influenced by the wettability of the fin surface.If the fin surface has good wettability, attached water will be less likely to form droplets, which will reduce ventilation resistance and increase the air volume, improving heat exchange efficiency. increase
In order to improve the wettability of the fin surface, conventional heat exchangers are constructed by combining fins and tubes, and then surface treatment is performed by immersing the fins in a solution. A method has been developed to easily form a hydrophilic film. However, when performing surface treatment after assembling the tube into a heat exchanger, the work is very cumbersome, as it is necessary to completely seal both ends of the tube, and the shape of the fins
Since there are restrictions on the fin pitch and the shape of the fins is complicated, it is difficult to form a uniform coating over the entire surface of the fins due to the formation of liquid pools, etc., resulting in variations in performance. Therefore, it may be possible to form a hydrophilic film on the coil material, which is the material of the aluminum fins, before it is assembled into the heat exchanger, but in this case, after the formation of the hydrophilic film, ,
It is necessary to press the coil material by cutting it to a predetermined fin length, drilling a tube insertion hole, and forming a cylindrical rising wall around the hole. When using the mineral oil-based lubricants currently in use, a problem arises in that the lubricants react with the hydrophilic film pre-formed on the surface of the coil material and deteriorate the hydrophilicity of the film. No treatment has been carried out to form a hydrophilic film on the surface of aluminum before it is assembled into a container. Purpose of the Invention The purpose of the present invention is to solve the above problems by forming a film having lubricating and hydrophilic properties on the surface of a plate-shaped aluminum material in advance, and pressing the aluminum material provided with this film. Therefore, the present invention aims to provide a method for producing aluminum fins for heat exchangers with high productivity in a shortened process and having a uniform hydrophilic film over the entire surface. Composition of the Invention In order to achieve the above-mentioned object, the present invention includes a surface of a plate-shaped aluminum material containing 1 to 50% by weight of a surfactant, a phosphorus-based extreme pressure additive, wax, and a higher fatty acid for the surfactant. A step of applying a solution containing 0.1 to 50% by weight of at least one of ester, petroleum resin, and polyethylene glycol, and drying the aluminum material to which this solution has adhered to impart lubricity to the surface of the aluminum material. The gist of this paper is a method for manufacturing aluminum fins for heat exchangers, which comprises a step of forming a hydrophilic film and a step of pressing the coated aluminum material. Hereinafter, the method of the present invention will be explained in detail in the order of steps. () Lubricant/hydrophilic film formation process Aluminum materials can be treated and processed in the form of a flat plate having the required length, but it is especially preferable to process and process them continuously in the form of a coil material. It is. The solution applied to the surface of the aluminum material is a solution in which a substance such as a phosphorus-based extreme pressure additive is added to a surfactant in a predetermined ratio. Surfactants are used to form a film with lubricity and hydrophilic properties on the surface of aluminum materials, and include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. use. Here, as the anionic surfactant, for example, fatty acid metal soaps such as sodium oleate, sodium naphthenate, sodium rosinate, sodium laudyl alcohol sulfate, laudyl ether sulfate, sodium alkylbenzene sulfonate, etc. are used. do. As the cationic surfactant, for example, disiloxyethylstearylamine, triethanolamine monostearate, 2-heptadecenylhydroxyethylimidazoline, lauryltrimethylammonium chloride, etc. are used. As the nonionic surfactant, for example, polyoxyethylene lanolin fatty acid ester, polyoxyethylene lauryl ether, polyoxyethylene nonyl phenyl ether, tallow fatty acid ethylene oxide adduct, polyoxyethylene stearyl ester, etc. are used. As the amphoteric surfactant, stearyl dimethyl betaine, methyl lauryl aminopropionate, etc. are used. Examples of solvents used include water, white kerosene, mineral spirits, benzene, toluene, xylene, and petroleum naphtha. The content of surfactant in the solution varies depending on the thickness of the film formed by drying the solution.If the film thickness is thin, the surfactant content should be reduced; conversely, if the film thickness is If it is thick, it is necessary to increase its content. Therefore, although this cannot be determined unconditionally, in consideration of both the hydrophilicity and lubricity of the film, the content of surfactant in the solution is preferably about 1 to 50% by weight. If the surfactant content is less than 1% by weight, it is difficult to form a film with good lubricity and hydrophilicity, and if it exceeds 50% by weight, the so-called blocking phenomenon may occur, or the mold may become damaged during press processing. This is not preferable because it may cause problems such as adhesion. The solution containing the surfactant further contains at least one substance selected from the group consisting of phosphorus extreme pressure additives, waxes, higher fatty acid esters, petroleum resins, and polyethylene glycols at a ratio of 0.1 to 0.1 to 100% of the surfactant.
It is added at a rate of 50% by weight. These substances are
It is added to improve lubricity and film-forming properties. Here, as the phosphorus-based extreme pressure additive, for example, dialkylhydrogen phosphite and trialkyl phosphite having 10 to 18 carbon atoms are used. As the wax, polyvinyl ether of octadecyl alcohol, montan wax, carnauba wax, etc. are used. As higher fatty acid esters, for example, carbon number
Esters of fatty acids such as lauric acid, palmitic acid, oleic acid, tallow fatty acid, alkenyl succinic anhydride and stearic acid having a carbon number of 10 to 20 and alcohols having 1 to 18 carbon atoms are used. As the petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, and dicyclopentadiene petroleum resin are used. If the above-mentioned substances such as phosphorus-based extreme pressure additives are less than 0.1% by weight, the lubricity and film-forming properties cannot be improved, and if it exceeds 50% by weight, it will adversely affect the hydrophilicity of the film. Undesirable. By applying the above solution to the surface of the plate-shaped aluminum material and drying it, a film having both lubricity and hydrophilicity is formed. The film thus formed, which has both lubricity and hydrophilicity, adheres well to the surface of the aluminum material mainly due to the action of the lipophilic group of the surfactant, and does not peel off. () Pressing process Heat exchanger fins are made by pressing the above-mentioned coated aluminum material having lubricity and hydrophilicity. Here, press working is a process for forming plate-like fins having tube insertion holes from the above-mentioned coated aluminum material, and includes, for example, overhanging, drawing, punching, curling, and tube insertion. This includes ironing, etc. to tighten and heighten the cylindrical rising wall around the insertion hole. Furthermore, when the aluminum material is a coil material, the shearing process that is performed subsequent to these processes to cut the aluminum material into a predetermined length is also included. Since the aluminum material has a film with good lubricity as described above, it can be pressed very smoothly and fins for heat exchangers can be made. In addition, in special cases where aluminum material is pressed under harsh conditions such as ironing,
A lubricant that increases lubricity, does not inhibit the hydrophilicity of the film, and has excellent detergency may also be used. Embodiments Next, embodiments of the present invention will be described. A heat exchanger fin was manufactured by the method of the present invention by sequentially carrying out the following steps. () Lubricating/hydrophilic film formation process First, after degreasing an aluminum (A1200) coil material with a thickness of 0.15 mm, a solution with the composition shown in the table below was applied to it, and then dried at 80°C for 1 minute. A film having lubricity and hydrophilicity was formed in an amount of approximately 200 mg/m ² . () Pressing process After forming a tube insertion hole by applying stretching, squeezing, punching, curling, and ironing to the above-mentioned coated coil material having lubricity and hydrophilic properties, the tube insertion hole is formed into a predetermined length. The fins for the heat exchanger were made by cutting the material into fins. Evaluation Test The contact angle of the heat exchanger fins produced in the above Examples was measured by adhering water to the heat exchanger fins, and the obtained results are summarized in the table below. For comparison, contact angles were also measured for heat exchanger fins manufactured by applying a conventional mineral oil-based lubricant to the above aluminum coil material and washing the lubricant with trichlene after pressing. The results obtained are shown in the same table. When water was applied to the surface of the original coil material and the contact angle was measured, it was 60°, and the contact angle of water on the coil material after degreasing was 45°.

[Table] As is clear from the above table, the fins according to the present invention have a very small contact angle of water adhering to the surface compared to the fins of the comparative example, and therefore are very easily wetted by water. The quality does not deteriorate over a long period of time. Furthermore, no cracking occurred in the fins during press working, and the lubricity was extremely good. Effects of the Invention As described above, the method for manufacturing an aluminum fin for a heat exchanger according to the present invention includes adding 1 to 50% by weight of a surfactant and extreme pressure phosphorus to the surfactant on the surface of a plate-shaped aluminum material. A step of applying a solution containing 0.1 to 50% by weight of at least one of waxes, higher fatty acid esters, petroleum resins, and polyethylene glycol, and drying the aluminum material to which this solution has adhered. The process consists of a process of forming a film with lubricity and hydrophilic properties on the surface, and a process of press working the aluminum material with this film, making it possible to manufacture heat exchanger fins extremely smoothly. The fins are hydrophilic, so in a heat exchanger assembled using these fins and tubes, water adhering to the fin surface is easily wetted and difficult to form into droplets, resulting in low ventilation resistance and high airflow. The heat exchange efficiency is high. In addition, since a treatment is performed to form a film having lubricity and hydrophilic properties on the surface of the aluminum material before pressing, workability is very good and the process can be shortened. Furthermore, since there is no need to apply lubricant during press working, the productivity of the fins is improved. Furthermore, since a film having lubricating and hydrophilic properties is formed on the surface of the aluminum material before pressing, the film is uniform over the entire surface of the aluminum material, so it is suitable for use in heat exchangers, for example. Even if the shape of the fin is complicated, it is possible to produce a fin having a uniform hydrophilic film over the entire surface. In addition, in the method of this invention, the surfactant-containing solution adhering to the aluminum material is dried to form a film before pressing, so the coiled aluminum material is It will not be cut by the press on the way. Therefore, according to the method of the present invention, it is possible to carry out continuous work from applying the solution to the coiled aluminum material to pressing, and the work efficiency is extremely high.

Claims (1)

[Claims] 1 Surfactant 1 on the surface of the plate-shaped aluminum material
~50% by weight of the surfactant and 0.1 to 50% by weight of at least one substance selected from the group consisting of phosphorous extreme pressure additives, waxes, higher fatty acid esters, petroleum resins, and polyethylene glycols. Aluminum for heat exchangers, which consists of a step of drying the aluminum material to which this solution has adhered to form a film having lubricity and hydrophilic properties on the surface of the aluminum material, and a step of press working the aluminum material with this film. Method for manufacturing fins.