JPH0832437B2 - Fin material for heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat exchanger fin material, and more particularly to a heat exchanger fin material in which condensed water is prevented from accumulating on the surface thereof.

(B) Conventional technology In some heat exchangers, fins made of aluminum having excellent heat conductivity are attached to improve heat exchange efficiency. When cooling is performed using this heat exchanger, warm air is cooled between the fins. At this time, condensed water may adhere to the surfaces of the fins. The condensed water that has adhered and accumulated may narrow the air passage between the fins to reduce the amount of ventilation, or generate noise. Further, the condensed water may be scattered in the ventilation direction and may contaminate various parts of the cooling device and various parts of the house.

For this reason, a method has been conventionally used in which the surface of the fin is made hydrophilic and the condensed water flows down as a thin water film. As a hydrophilic method, for example, a method of applying a mixture of acrylic acid resin and water glass is known.

However, since this flow-down method treats condensed water at the interface between the fins and the atmosphere (that is, the surface of the fins), water changes due to changes in the surface condition of the fins (for example, dust accumulation or water-repellent substance adhesion). There was an inherent drawback that it prevented the flow of water. Further, for example, when an inorganic compound such as water glass is used for the hydrophilic treatment, the presence of this inorganic compound causes cracks when the fins are perforated or bent, and the coating film is easily peeled off. There was a flaw.

Therefore, the present inventors diligently studied to solve this point,
In Japanese Patent Application No. 60-221645, we proposed a fin material for a heat exchanger in which a mixed layer of an adhesive and super absorbent resin powder was formed on the surface of the fin material body. The fin material for heat exchangers according to this proposal is to absorb condensed water in the surface layer of the fin (mixed layer of adhesive and super absorbent resin powder), and to treat condensed water in the layer. Moreover, since the surface layer is composed of only the organic compound, the above-mentioned drawbacks can be completely solved.

(C) Problems to be Solved by the Invention However, since the superabsorbent resin powder used in the proposal of Japanese Patent Application No. 60-221645 has an excessive ability to absorb water and retain it, the condensed water is layered. There was a drawback that it was difficult to let it flow down inside. Further, when a large amount of water is retained, the swollen superabsorbent resin powder may drop off from the surface layer of the fin due to ventilation. Furthermore, because the surface layer is a mixture of adhesive and superabsorbent resin powder,
It also had the drawback of being inferior in mechanical strength.

Therefore, the present invention eliminates the above-mentioned drawbacks by applying a specific composition to the fin material main body, and particularly attempts to cause water to flow down in the fin surface layer immediately after absorbing condensed water. is there.

(D) Means and Actions for Solving the Problems That is, according to the present invention, a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, pullulan, and a chelate compound coordinated with pullulan are attached to the surface of the fin material main body. The present invention relates to a fin material for a heat exchanger, which is obtained by applying a pullulan-based composition containing a produced metal compound.

As the fin material main body, any material can be used as long as it has good heat conductivity, but in particular, it is excellent in heat conductivity, easy to perform various molding processes, and light in weight. Most preferred is aluminum sheet.

A pullulan-based composition is applied to the surface of the fin body. The pullulan-based composition comprises a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, pullulan, and a metal compound coordinated to the pullulan to form a chelate compound.

As the water-soluble melamine resin, either a commercially available monomer resin or a polymer resin such as a dimer type resin having a degree of polycondensation advanced to some extent may be used. As the curing catalyst for the water-soluble melamine resin, ammonium salt-based catalysts such as ammonium chloride, dibasic ammonium phosphate, and ammonium sulfamate, hydrochloric acid or sulfamate of organic amino alcohol, other dimethylaniline hydrochloride, pyridine-hydrochloric acid-based catalyst, Organic amine catalysts such as picoline-monochloroacetic acid,
Inorganic metal catalysts such as magnesium chloride, zinc chloride and zinc sulfate can be mentioned. Above all, it is preferable to use an organic amine salt catalyst. The water-soluble melamine resin becomes a three-dimensional network polymer by its curing catalyst and serves as a substrate for the surface layer formed on the fin body.

Pullulan is a type of black yeast, Aureobasid-ium pu
llulans is a viscous polysaccharide produced outside the bacterium, that is, in the culture broth, when sucrose or starch hydrolyzate is used as a carbon source and other peptone or various salts are added to the medium and cultured under appropriate conditions. . The pullulan thus obtained is a linear polymer and has the following molecular structure.

Pullulan is extremely hydrophilic and water-soluble, and also has excellent adhesiveness and film-forming properties. Pullulan is insolubilized by a metal compound that forms a chelate compound by being coordinated with the pullulan. Zirconium nitrate is generally used as the metal compound, but other zirconium salts and the like can also be used. Pullulan improves the hydrophilicity of the surface layer applied to the surface of the fin material body.

The quantitative ratio of each component in the pullulan-based composition is about 50 to 200 parts by weight, preferably about 80 to 180 parts by weight, with respect to 100 parts by weight of the water-soluble melamine resin. If the amount of pullulan is less than 50 parts by weight, the hydrophilicity of the surface layer tends to be insufficient, and if the amount exceeds 200 parts by weight, the degree of hydrophilicity of the surface layer tends not to be improved so much.

The amount of the metal compound coordinated to pullulan to form a chelate compound is about 2 to 10 parts by weight, preferably about 4 to 7 parts by weight, based on 100 parts by weight of pullulan. If the amount of the metal compound is less than 2 parts by weight, the insolubilization of pullulan tends to be incomplete, and if it exceeds 10 parts by weight, the hydrophilicity of pullulan tends to decrease. The amount of the water-soluble melamine resin curing catalyst may be an amount sufficient to cure the water-soluble melamine resin, for example, the water-soluble melamine resin 10
It is 0.1 to 5 parts by weight with respect to 0 parts by weight.

The pullulan-based composition is applied to the surface of the fin body by adjusting the pullulan-based composition into an aqueous solution. To prepare an aqueous solution, for example, pullulan and a metal compound that coordinates with the pullulan to form a chelate compound, for example, zirconium admired, are dissolved in water to prepare a liquid A. Separately from solution A, water-soluble melamine resin and its curing catalyst are dissolved in water to prepare solution B. Then, the liquid A and the liquid B are mixed and intensively stirred for adjustment.

The fin material for a heat exchanger according to the present invention can be obtained by applying the aqueous solution of the pullulan-based composition on the surface of the fin material body and drying it.

(E) Example Example 1 First, a pullulan-based composition having the composition shown below was prepared.

Water-soluble melamine resin 100 parts by weight Guanidine sulfamate 0.5 parts by weight Pullulan 100 parts by weight Zirconium nitrate 6 parts by weight Aqueous solution concentration 20% by weight This pullulan-based composition is degreased on an aluminum sheet (JIS A-1100, thickness 0.15 mm , Size 200mm × 300mm)
Was applied with a # 6 bar coater and dried in a hot air dryer at 180 ° C. for 3 minutes to obtain a fin material for a heat exchanger.

Example 2 A fin material for a heat exchanger was obtained under the same conditions as in Example 1 except that the following pullulan-based composition was used.

Water-soluble melamine resin 100 parts by weight Ammonium chloride 0.7 parts by weight Pullulan 77 parts by weight Zirconium nitrate 4 parts by weight Aqueous solution concentration 15% by weight Example 3 A heat exchanger under the same conditions as in Example 1 except that the following pullulan-based composition was used. I got the fin material.

Water-soluble melamine resin 100 parts by weight Methylaniline 0.7 parts by weight Pullulan 77 parts by weight Zirconium nitrate 4 parts by weight Aqueous solution concentration 13% by weight The fin material obtained in Examples 1 to 3 is subjected to a predetermined perforation process to form a fin for a heat exchanger. I attached it as. as a result,
Condensed water was immediately absorbed in the pullulan-based composition of the surface layer without water appearing on the surface of the fin, and flowed down by its own weight.

(F) Effect of the invention Since the fin material for a heat exchanger according to the present invention has an organic polymer as a main component of its surface layer, the fin material is coated with a coating film when the fin material is punched or bent. It is possible to prevent the occurrence of cracks in the (surface layer of the pullulan-based composition), and to improve the durability of the coating film and thus the durability of the fin material.

Further, the fin obtained by using the fin material for the heat exchanger according to the present invention does not treat the condensed water on the surface thereof, but in the surface layer, so that the surface of the fin is not dusted or repelled. Even if an aqueous substance adheres, the condensed water can be quickly removed from the fin surface.

In the surface layer of the fin material according to the present invention, chelated pullulan is used as a substance having an affinity for condensed water in place of the super absorbent resin powder used in the proposal of Japanese Patent Application No. 60-221645. Since it is used, it has a small ability to retain condensed water even if it absorbs water, and the water flows down quickly due to its own weight. Therefore, the condensed water can be quickly removed from the fin surface.

Further, the surface layer of the fin material for heat exchanger according to the present invention,
Since it consists of melamine resin with a three-dimensional network structure and pullulan with good film-forming properties, it has high mechanical strength and the surface layer is less likely to be damaged or destroyed during handling. In addition, since pullulan has a good film-forming property, it has an effect of less falling off as compared with the conventional super absorbent polymer powder.

Claims (1)

[Claims] 1. A pullulan-based composition containing a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, pullulan, and a metal compound coordinated with the pullulan to form a chelate compound on the surface of the fin material body. A fin material for a heat exchanger, which is characterized by being applied.