JPH04108575A - Manufacture of heat-exchanger's fin having undercoating with high waterproof adhesion strength - Google Patents

Abstract

PURPOSE:To make the waterproof adhesion strength between a hydrophilic film and an undercoat film on the surface side high even under highly humid environment by forming a hydrophilic film on the surface of an undercoat film after the undercoating film is formed on the surface of a fin made of aluminum. CONSTITUTION:An aqueous solution containing a water-soluble organic polymer resin to which sulfonic acid residues or its salts are introduced and a water-soluble cross-linking agent (inorganic, organic) is applied to the surface of a fin made of aluminum. Then, the sulfonated water-soluble organic polymer resin and the cross-linking agent are reacted each other by heating to form an undercoating film on the surface of the fin made of aluminum. Next, a hydrophilic coat forming agent of mainly alkali silicate (A) and a lower molecular weight organic compound (B) having carbonyl group is applied to the surface of the undercoating film, The undercoating stuck fin to which the hydrophilic coat forming agent is applied is further heated to react (A) and (B) and form a hydrophilic coating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing fins for heat exchangers having a base film with excellent water-resistant adhesion.

In this specification, aluminum includes aluminum and aluminum alloys.

2. Description of the Related Art In the past, various techniques have been proposed for surface treatment of aluminum fin materials for heat exchangers. For example, conventionally, a method has been known in which a surface-treated fin material with excellent corrosion resistance, moldability, and heat yellowing resistance is produced by surface-treating aluminum fin material using a treatment agent containing a synthetic resin and a metal-containing compound. (For example, JP-A-82-2
(See Publication No. 478813).

Conventionally, after performing a base treatment to contain a hardening agent that makes water glass (alkali silicate) insoluble in the organic polymer resin constituting the base film, the fin material with the base film is treated with an aqueous solution of silicate. A hydrophilic treatment method is known.

Problems to be Solved by the Invention However, when a water glass film is formed on a base film mainly composed of an organic polymer resin as in the conventional method, it may be left in an extremely humid environment or exposed to water during the pressing process. When a strong external force is applied to the glass film, a situation occurs in which the water glass film falls off little by little, leading to problems such as poor appearance and deterioration of hydrophilicity of heat exchangers such as evaporators. There was also the problem that there was a concern that the press mold would be worn out by the pieces of water glass that fell off.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to achieve extremely good adhesion (water-resistant adhesion) between the hydrophilic film on the surface side and the base film even in a high humidity environment, and to achieve excellent Hydrophilicity can be maintained for a long period of time, and therefore, water droplets that adhere to the fins immediately spread into a film and are removed by flowing down, eliminating the possibility of increased ventilation resistance due to water droplets adhering to the fins, greatly improving heat exchange efficiency. It is an object of the present invention to provide a method for manufacturing a fin for a heat exchanger, which has a base film that increases the number of fins, has good moldability, reduces press die wear, and has excellent water-resistant adhesion.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention first provides a method for manufacturing heat exchanger fins having a base film with excellent water-resistant adhesion according to the first invention. To,
An aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-8O3H) or its salt has been introduced and a water-soluble crosslinking agent (inorganic type, organic type) is applied, and the fin material coated with this aqueous solution is The first step is to form a base film on the surface of the aluminum fin material by heating and reacting the sulfonated water-soluble organic polymer resin with the crosslinking agent. A) and a hydrophilic film-forming agent whose main components are a low-molecular-weight organic compound (B) having a carbonyl group are applied, and the fin material with the base film coated with the hydrophilic film-forming agent is heated to form an alkali silica film. A low molecular weight organic compound (B) having an acid salt (A) and a carbonyl group
) to form a hydrophilic film.

In addition, the second aspect of the present invention, the method for producing heat exchanger fins according to the invention, involves reacting a water-soluble organic polymer resin into which a sulfonic acid group (-8O3H) or a salt thereof has been introduced with a crosslinking agent to form a base film. The first step of forming the film is the same as in the first invention, but the hydrophilic film forming agent in the second step is further blended with a water-soluble organic polymer compound (C) to form an alkali silicate (A ) and low-molecular organic compounds with carbonyl groups (
It is characterized in that a hydrophilic film is formed using a hydrophilic film forming agent containing B) and a water-soluble organic polymer compound (C) as main components.

Furthermore, the method for manufacturing heat exchanger fins according to the third aspect of the present invention includes forming a base film by reacting a water-soluble organic polymer resin into which a sulfonic acid group (-8Oi H) or a salt thereof is introduced with a crosslinking agent. The first step is the same as in the first invention, but in the second step, an aqueous solution containing a water-soluble organic polymer compound (C) and a low-molecular organic compound (B) having a carbonyl group is prepared. The fin material with the base film coated with this aqueous solution is heated to cause the water-soluble organic polymer compound (C) and the low-molecular organic compound (B) to react, thereby forming an organic hydrophilic film. It is characterized by

In the above, the aluminum fin material can be processed and processed in the form of a flat plate having the required length, but it is particularly preferable to process and process it continuously in the form of a coil.

In the first step of the method of this invention, the following organic polymer resins may be used to introduce sulfonic acid groups (-so, H).

(i) Vinyl polymers such as vinyl acetate, vinyl chloride, vinylidene chloride, and copolymers thereof, into which sulfonic acid groups have been introduced.

(if) Acrylic polymers such as acrylic acid, methacrylic acid and their esters, acrylamide, and copolymers thereof, into which sulfonic acid groups have been introduced.

(iii) Styrene-based, olefin-based, urethane-based, polyester-based, alkyd-based, epoxy-based polymers and copolymers thereof, into which sulfonic acid groups have been introduced.

(jv) Synthetic rubber type with sulfonic acid groups introduced.

In addition, in this specification, for convenience, synthetic rubber into which a sulfonic acid group has been introduced is included in the water-soluble organic polymer resin into which a sulfonic acid group has been introduced.

Here, there are generally two methods for introducing a sulfonic acid group into the above polymer.

First, a method of polymerizing or copolymerizing a heptamer having a sulfonic acid group.

Here, examples of the monomer having a sulfonic acid group include vinylsulfonic acid, styrenesulfonic acid, and 2-acrylamide-2methylpropanesulfonic acid.

Second, a method in which a sulfonating agent is applied to a polymer or copolymer to introduce sulfonic acid groups into the polymer or copolymer.

As a sulfonating agent, salts of bisulfite such as sodium, potassium and ammonium salts of bisulfite are generally used, but in some cases, sulfite gas is used to adjust bisulfite in the system. However, it can also be subjected to a reaction.

In the reaction, it is preferable to use an oxide as a reaction accelerator, such as peroxides such as potassium persulfate, potassium nitrate, sodium nitrate,
Examples include nitrates such as ammonium nitrate, hydrogen peroxide, oxygen, and organic peroxides.

The proportion of the sulfonating agent used in the reaction is appropriately selected depending on the desired product, but since the reaction generally proceeds quantitatively, it is sufficient to use a theoretical amount or a slightly excess amount. .

In addition, it is appropriate that the pH during the sulfonation reaction be 8 or less, preferably 7 to 5; if the pH value becomes too large, the reactivity will be inhibited, and on the other hand, if the pH value is too small, the sulfonation product will be is not preferred because of its poor solubility.

The reaction temperature is usually room temperature to 1SO℃, and the reaction time is 1
~25 hours, but is not limited to this, of course.

The content of sulfonic acid groups (-8O3H) in the organic polymer resin varies depending on the conditions of the sulfonation reaction, the amount of organic polymer resin used in the reaction, etc. It is preferred that about 50%, especially about 5 to 40%, be sulfonated.

The weight average molecular weight of the organic polymer resin before sulfonation is 1
000-200000, preferably 5000-1000
It is 00.

Note that after producing the organic polymer resins or synthetic rubbers in (i) to (1v) above, they are sulfonated using the sulfonating agent described above, but the components of these organic polymer resins or synthetic rubbers are In some cases, the sulfonated component is preliminarily sulfonated using a sulfonating agent, and then the sulfonated component is polymerized.

The sulfonic acid group (-8O3H) of the above water-soluble organic polymer resin
) may be present in the form of salt. As the cation constituting the salt of the sulfonic acid group of such a water-soluble organic polymer resin, for example, alkali metals, alkaline earth metals, ammonium, amines, etc. are used.

Here, examples of alkali metals include sodium and potassium, and examples of alkaline earth metals include calcium and magnesium.

Examples of amines include alkylamines such as methylamine, ethylamine, propylamine, dimethylamine, diethylamine, triethylamine, and butylamine, and polyamines such as ethylenediamine and diethylenetriamine.

Specifically, the water-soluble organic polymer resin into which the sulfonic acid group (-SO3H) or a salt thereof is introduced includes a copolymer of acrylamide/2-acrylamide-2methylpropanesulfonic acid, and sodium styrene sulfonate. - Examples include acrylamide copolymers, sulfonated polyacrylamide, sulfonated polystyrene, etc.

Further, the water-soluble cross-linking agent used in the first step of the method of this invention includes a water-soluble inorganic cross-linking agent and a water-soluble organic cross-linking agent, and either one of the two may be used, or both may be used in combination. You may do so.

These water-soluble crosslinking agents have the above-mentioned sulfonic acid group (-so,
An appropriate one is used depending on the type of water-soluble organic polymer resin into which H) or its salt is introduced.

That is, for example, when a water-soluble organic polymer resin into which a sulfonic acid group (-8O3H) or a salt thereof has been introduced is an organic polymer resin having active hydrogen, two or more isocyanates are used as a water-soluble crosslinking agent. A compound that can react with active hydrogen, such as a group, an aziridyl group, a glycidyl group, or a methylol group, is used.

Further, when the water-soluble organic polymer resin is an oligomer or organic polymer resin having an unsaturated group, an unsaturated compound copolymerizable with the oligomer or organic polymer resin is used as the water-soluble crosslinking agent.

Furthermore, when the water-soluble organic polymer resin is an organic polymer resin made of a water-soluble polymer or copolymer containing oxygen or nitrogen, a metal compound that can form a complex compound with these is used as a water-soluble crosslinking agent. Use. In this case, the crosslinking agent acts as a crosslinking insolubilizer. In particular, it is preferable to use metal compounds with a coordination number of 4 or more, including Cr, Ti,
It is effective to use 5Al and Zn compounds.

In the first step of the method of this invention, the blending ratio of the water-soluble organic polymer resin into which the sulfonic acid group (-8O3H) or its salt has been introduced and the water-soluble crosslinking agent (inorganic type, organic type) is 0.0% water-soluble crosslinking agent per 1 part by weight of organic polymer resin. It is 1 to 5 parts by weight.

Here, if the water-soluble crosslinking agent is less than 0.1 part by weight per 1 part by weight of the water-soluble organic polymer resin into which a sulfonic acid group (-3O3H) or its salt has been introduced, the crosslinking density during heat drying will be low. 5, the base film is not sufficiently formed into a film, and
If the amount exceeds 1 part by weight, the life of the base treatment liquid (pot life) will be shortened, which is not preferable.

Note that the water-soluble organic polymer resin into which a sulfonic acid group (-so, n) or a salt thereof has been introduced and the water-soluble crosslinking agent are used after being diluted with water. The dilution ratio is based on the hydrophilicity of the base film,
It is necessary to determine this by considering film thickness and workability.

In order to treat the surface of the aluminum fin material with an aqueous solution of the above-mentioned compound, the aluminum fin material may be applied by spraying, roll coating, flow coating, or by immersing the aluminum fin material in the aqueous solution.

The aluminum fin material after being treated with an aqueous solution is 10
at a temperature of 0 to 2 SO °C, preferably 150 to 230 °C,
It is heated and dried for 5 seconds to 20 minutes to form a hydrophilic base film on the surface.

Here, if the heat drying temperature is less than 100°C, the composition will not form a film sufficiently, and if it exceeds 2SO°C, further heating will not only have no effect but will also have a negative effect on the aluminum material. If the heat drying time is less than 5 seconds, the composition will not form a film sufficiently, and if it exceeds 20 minutes, productivity will decrease. And the heat drying temperature is 1SO~2
When the temperature is as high as SO 0 C, the drying time may be as short as 30 seconds to 1 minute, but when the temperature is low, the drying time needs to be longer. If heat drying is insufficient, the formulation will not form a film sufficiently.

Further, the hydrophilic base film is formed on the surface of the aluminum fin material to a thickness of 10p or less, preferably 0.02 to 21m. Here, if the thickness of the base film exceeds 10711777, it is not preferable because it takes a long time to dry and the heat exchange performance deteriorates.

Next, the alkali silicate (A) in the second step of the present invention constitutes the main component for imparting hydrophilicity to the film, and is 5102/M20 (where M is lithium, sodium, It is necessary to use a metal having a ratio of 1 or more (meaning an alkali metal such as potassium).

In particular, it is preferable to use an alkali silicate having 2 to 5 51027M20.

Further, the low molecular weight organic compound (B) in the second step of this invention is a low molecular weight organic compound having a carbonyl group (>C-0) in the molecule, and this is an alkali silicate (
This stabilizes the film formed by A), improves its hydrophilicity, and imparts flexibility to the film.

Specific examples of such low-molecular organic compounds (B) include aldehydes, esters, and amides.

Here, as the aldehydes, formaldehyde, acetaldehyde, glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, furfuraldialdehyde, etc. are used.

Examples of esters include fatty acid esters of monohydric alcohols such as methyl formate, ethyl acetate, methyl acetate, butyl acetate, amyl acetate, and methyl propionate, as well as ethylene glycol diacetate, glycerine triacetate, and ethylene glycol dipropionate. Fatty acid esters of polyhydric alcohols such as esters, intramolecular esters such as γ-butyrolactone and ε-caprolactone,
Also, ethylene glycol monoformate, ethylene glycol monoacetate, ethylene glycol monopropionate, glycerin monoformate, glycerin monoacetate, glycerin monopropionate, glycerin diformate, glycerin diacetate, sorbitol monoformate , sorbitol monoacetate, and polyhydric alcohol partial esters such as glycose acid monoacetate, and polybasic acids such as dimethyl succinate and dimethyl maleate.
Hydrolic alcohol esters and cyclic carbonates such as ethylene carbonate, propylene carbonate, and glycerin carbonate are used.

Further, as the amides, formamide, dimethylformamide, acetamide, dimethylacetamide, propionamide, butyramide, acrylamide, malondiamide, pyrrolidone, caprolatam, and the like are used.

Among the low-molecular organic compounds (B), water-soluble compounds are preferably used in order to perform uniform treatment,
In particular, it is preferred to use aldehydes and esters.

Next, in the second step of the present invention, the water-soluble organic polymer compound (C) has a hydrophilic coating formed from an alkali silicate (A) and a low molecular weight organic compound (B) having a carbonyl group. This further improves flexibility and flexibility.

Specifically, such water-soluble organic polymer compounds (C) include polysaccharide-based natural polymers, water-soluble protein-based natural polymers, anionic, nonionic, or cationic addition-polymerized water-soluble synthetic polymers. , and polycondensation water-soluble polymers.

Here, the polysaccharide natural polymers include soluble starch,
Carboxymethyl cellulose, hydroxyethyl cellulose, guar gum, gum tragacanth, xanthan gum, sodium alginate, etc. are used. Gelatin or the like is used as the water-soluble protein-based natural polymer.

Examples of anionic or nonionic addition polymer water-soluble polymers include polyacrylic acid, sodium polyacrylate, polyacrylamide, partial hydrolysates thereof, polyvinyl alcohol, polyhydroxyethyl amarylate, polyvinylpyrrolidone, and acrylic acid copolymers. and maleic acid copolymers and their alkali metal, organic amine and ammonium salts.

Furthermore, water-soluble synthetic polymers modified by carboxymethylation or sulfonation of the above-mentioned addition polymerized water-soluble synthetic polymers can also be used.

Examples of cationic addition-polymerized water-soluble synthetic polymers include polyethyleneimine, Mannich-modified compounds of polyacrylamide, diacryldimethylaluminum chloride,
Polyalkylamino (meth)acrylates such as polyvinylimidacillin and dimethylaminoethyl acrylate polymers are used.

Polycondensation water-soluble synthetic polymers include polyalkylene polyols such as polyoxyethylene glycol and polyoxyethylene oxypropylene glycol, polycondensates of epichlorohydrin and polyamines such as ethylenediamine or hexamethyldiamine, and water-soluble polyethers and polyesters. Water-soluble polyurethane resin, polyhydroxymethylurea resin, polyhydroxymethylmelamine resin, etc., which are polycondensed isocyanates, are used.

Among the above-mentioned water-soluble organic polymer compounds (C), it is preferable to use an anionic addition-polymerized water-soluble polymer having a carboxylic acid or a carboxylic acid group, particularly polyacrylic acid, acrylic acid copolymer, maleic acid Preference is given to using copolymers and their alkali metal salts. Here, the acrylic acid copolymer and maleic acid copolymer include copolymers of acrylic acid and maleic acid, as well as acrylic acid or maleic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, Preferably, a copolymer with hydroxyethyl methacrylate, itaconic acid, vinyl sulfonic acid, or acrylamide is used.

In the second step of the first invention and M2 invention, the blending ratio of the alkali silicate (A), the low molecular weight organic compound having a carbonyl group (B), and the water-soluble organic polymer compound (C) is as follows: It is as follows.

First, in the case of (A) + (B), the alkali silicate (A)
The low molecular weight organic compound (B) having a carbonyl group is blended at a ratio of 0.1 to 5 parts by weight per 1 part by weight.

Next, in the case of (A) + (B) + (C), 0.1 to 5 parts by weight of the low molecular weight organic compound (B) having a carbonyl group is added to 1 part by weight of the alkali silicate (A). Department,
and a water-soluble organic polymer compound in a proportion of 0.01 to 5 parts by weight.

In the above, if the amount of the alkali silicate (A) in the hydrophilic film forming agent is small, a sufficient hydrophilic film will not be formed on the surface of the base film. On the other hand, if the amount is too large, the film becomes too hard, resulting in poor moldability and mold wear resistance.

Further, if the low molecular weight organic compound (B) having a carbonyl group is less than 0.1 part by weight per 1 part by weight of the alkali silicate (A), the effect of adding the low molecular weight organic compound (B) will not be exhibited. Moreover, if it exceeds 5 parts by weight, the amount of alkali silicate (A) will be relatively small, so that sufficient hydrophilicity will not be exhibited.

The water-soluble organic polymer compound (C) is an alkali silicate (A
) If the amount is less than 0.01 part by weight per 1 part by weight, the effect of adding the polymer compound (C) will not appear, and if it exceeds 5 parts by weight, the formed film will be eluted into water, The lasting effect of hydrophilicity decreases.

In the second step of the third invention, the water-soluble organic polymer compound (C) and the low molecular weight organic compound (B) having a carbonyl group are used after being dissolved in water. These blending ratios must be determined taking into account the hydrophilicity, film thickness, and workability of the film, but it is important to note that the proportion of the low-molecular organic compound having a carbonyl group per 1 part by weight of the water-soluble organic polymer compound (C) (B
) is preferably used in an amount of 0.5 to 2 parts by weight.

Here, if the amount of the low molecular organic compound (B) is less than 0.5 parts by weight with respect to 1 part by weight of the water-soluble organic polymer compound (C), the effect of the crosslinking reaction will be insufficient, and 2 parts by weight If it exceeds the amount, the amount of the low-molecular organic compound CB) used is too large and does not contribute to the reaction, which is wasteful.

In the first to third inventions above, the alkali silicate (A)
and a low molecular weight organic compound (B) having a carbonyl group,
The water-soluble polymer compound (C) is used after being diluted with water. The dilution ratio must be determined in consideration of the hydrophilicity, film thickness, and workability of the film.

As mentioned above, the surface of the aluminum fin material with a base film made of a water-soluble organic polymer resin into which a sulfonic acid group (-8Oi H) or a salt thereof has been introduced and modified with a water-soluble crosslinking agent was coated with the above (^ ) +(B),(A)
To treat with an aqueous solution of the hydrophilic treatment agent +(B) +(C) or (B)+(C), use spray, brushing, roll coating, or flow coating as in the case of the above-mentioned surface treatment. The aluminum fin material can be coated or immersed in an aqueous solution.

The aluminum fin material after being treated with an aqueous solution of a hydrophilic treatment agent has a temperature of 100 to 2SO℃, preferably 150 to 23℃.
It is heated and dried at a temperature of 0° C. for 5 seconds to 30 minutes to form a hydrophilic film on the surface.

Here, if the heat drying temperature is less than 100°C, the hydrophilic treatment agent will not form a film sufficiently, and if it exceeds 2SO°C,
Further heating will not only have no effect, but will also have a negative effect on the aluminum material. In addition, if the heating drying time is less than 5 seconds, the hydrophilic treatment agent will not form a film sufficiently, and the
If it exceeds 1 minute, productivity will decrease. If the heat drying temperature is high, such as 1SO to 2SO''C, the drying time may be as short as 5 seconds to 1 minute, but if the temperature is low, the drying time must be longer. If it is insufficient,
The hydrophilic treatment agent is not formed into a film sufficiently.

Also, the above (A) + (B), (A) + (B) +
The hydrophilic film of each component (C) or (B) + (C) is formed on the surface of the base film at a rate of 0.1 to 10 g/s2, preferably 0.5 to 3 g/s2. do.

Here, the film is 0. If it is 1 g/■2 or more, the initial hydrophilicity is good, but in order to maintain even better hydrophilicity, 0. It is preferable to form a film of 5 g/m2 or more. Moreover, if the coating weight exceeds 10 g 1 2, it is not preferable because it takes a long time to dry and has an adverse effect on press formability.

The aqueous solution of the hydrophilic treatment agent may contain conventionally known additives, such as inorganic rust preventives such as sodium nitrite, sodium polyphosphate, and sodium metaborate, benzoic acid and its salts, halanitrobenzoic acid, and the salt,
Of course, an organic rust preventive agent such as cyclohexylamine carbonate or benzotriazole may be added.

Finally, the aluminum fin material having the base film and hydrophilic film obtained as described above is pressed to produce a fin for a heat exchanger.

Here, press processing is a process for forming a plate-like fin having a tube insertion hole from the film-covered fin material, and includes 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 fin material is a coil material, the shearing process that is performed subsequent to these processes to cut the fin material into a predetermined length is also included.

The heat exchanger fins having the sulfonic acid group-introduced base film and the specific hydrophilic film manufactured by the methods of the first to third inventions of the present invention have relatively soft film components, so press molds wear out. It has a small amount of heat exchanger fins, has excellent moldability and mold abrasion resistance, and can be pressed very smoothly, making it possible to efficiently produce fins for heat exchangers.

In addition, the heat exchanger fins produced by the method of this invention all have extremely excellent hydrophilicity, and even in high humidity environments, the water-resistant adhesion between the hydrophilic film on the surface side and the base film is extremely high. In good condition. Therefore, for example, even in the case of the first and second inventions described above, in which alkali silicate (^), that is, water glass is used as a component of the hydrophilic film, the water glass may be left in an extremely high humidity environment, or the water glass may be removed during the pressing process. Even if a strong external force is applied to the water glass-containing hydrophilic film, the water glass-containing hydrophilic film will not fall off, and problems such as poor appearance of heat exchangers such as evaporators and deterioration of hydrophilicity will not occur at all. It is.

Example Next, examples of the present invention will be described together with comparative examples.

Example 1 As an aluminum fin material, thickness 0.2111 width 5
JISA-1100H with 011% and length 100mm
24 aluminum thin plates were used.

A sulfonic acid group (-8O
50 g/l of a copolymer of acrylamide/2-acrylamide-2methylpropanesulfonic acid as a water-soluble organic polymer resin into which x 25g
/I is applied, and the fin material coated with this aqueous solution is heated at 200°C for 15 minutes to cause the sulfonated water-soluble organic polymer resin to react with the crosslinking agent. A base film was formed on the surface.

Next, alkali silicate (A) 2
Weight %, low molecular weight organic compound (B) having a carbonyl group
A hydrophilic film-forming agent containing 2% by weight of γ-butyrolactone as a water-soluble organic polymer compound (C) and 2% by weight of sodium salt of an acrylic acid/vinyl acetate copolymer as a water-soluble organic polymer compound (C) is applied. The fin material with the base film coated with the film forming agent was heated at 200°C for 1 minute to form the alkali silicate (^), the low molecular weight organic compound (B) having a carbonyl group, and the water-soluble organic polymer compound ( A hydrophilic film was formed by reacting with C).

Finally, the thin aluminum plate having the base film and the hydrophilic film was molded to produce fins for a heat exchanger.

In addition, as the alkali silicate (A), Sl 0
2 /Na20 ratio of 3 was used.

Comparative Example 1 For comparison, 50 g/i of acrylamide/2-acrylamide-ethylamine copolymer as a water-soluble organic polymer resin in which no sulfonic acid groups have been introduced and a water-soluble cross-linked resin were added to the surface of the aluminum thin plate. Sulfonic acid groups were introduced in exactly the same manner as in Example 1 above, except that an aqueous solution containing chromic anhydride (2 g/I) and zirconium fluoride (25 g/L) was applied as the agent. A heat exchanger fin was manufactured by molding a thin aluminum plate having an untreated base film and a hydrophilic film.

Example 2 On the surface of the same aluminum thin plate as in Example 1 above,
In the same manner as in Example 1, the sulfonic acid group (-8(h
A base film into which H) was introduced was formed.

Next, alkali silicate (A
) 5% by weight, a low molecular weight organic compound having a carbonyl group (
As B), a hydrophilic film-forming agent containing 5% by weight of γ-butyrolactone is applied, and the fin material coated with the base film coated with this hydrophilic film-forming agent is heated at 200°C for 1 minute to form an alkali film. A hydrophilic film was formed by reacting the silicate with γ-butyrolactone. and,
A thin aluminum plate having this base film and a hydrophilic film was molded to produce a fin for a heat exchanger.

Comparative Example 2 For comparison, a copolymer of acrylamide/2-acrylamide-ethylamine (50 g/l) as a water-soluble organic polymer resin into which no sulfonic acid group has been introduced and a water-soluble crosslinked resin were added to the surface of the aluminum thin plate for comparison. As agent chromic anhydride 2glfl and fluoridated zirconium 25g#! An aluminum thin plate having a base film in which no sulfonic acid groups were introduced and a hydrophilic film was formed by the same operation as in Example 2 above, except for applying an aqueous solution containing , manufactured fins for heat exchangers.

Example 3 On the surface of the same aluminum thin plate as in Example 1 above,
The same acrylamide 2- as in Example 1 was used as the water-soluble organic polymer resin into which sulfonic acid groups (-8o, H) were introduced.
50 g/fI of a copolymer of acrylamide-2-methylpropanesulfonic acid is used, with 1 gfl of chromic anhydride and 10 gf of zirconammonium hydrofluoride as water-soluble inorganic crosslinking agents and 5 gfl of water-soluble polyurethane as water-soluble organic crosslinking agents. The fin material coated with this aqueous solution is heated at 200°C for 1 minute to cause the sulfonated water-soluble organic polymer resin to react with the crosslinking agent, thereby forming a base on the surface of the aluminum thin plate. A film was formed.

Next, a water-soluble organic polymer compound (
A hydrophilic film forming agent containing 5% by weight of sodium acrylate/acrylamide copolymer as C) and 5% by weight of γ-butyrolactone as the low molecular weight organic compound having a carbonyl group (B) was applied. By heating the fin material with the base film coated with the hydrophilic film forming agent at 190°C for 1 minute to cause the sodium acrylate/acrylamide copolymer and γ-butyrolactone to react,
A hydrophilic film was formed.

Finally, the thin aluminum plate having the base film and the hydrophilic film was molded to produce fins for a heat exchanger.

Comparative Example 3 For comparison, 50 g of a copolymer of acrylamide/2-acrylamide-ethylamine (50 g#) as a water-soluble organic polymer resin into which no sulfonic acid group has been introduced and a water-soluble cross-linked resin were added to the surface of the aluminum thin plate. A sulfonic acid group was introduced in exactly the same manner as in Example 3 above, except that an aqueous solution containing 2 g/i of chromic anhydride and 25 g/l of zirconium fluoride was applied as the agent. A heat exchanger fin was manufactured by molding a thin aluminum plate having a free base film and a hydrophilic film.

Example 4 On the surface of the same aluminum thin plate as in Example 1 above,
As a water-soluble organic polymer resin into which sulfonic acid groups (-8Oi H) have been introduced, 50 g/ρ of a copolymer of sodium styrene sulfonate and acrylamide is used, or 15 g/Ω of water-soluble polyurethane is used as a water-soluble organic crosslinking agent. The fin material coated with this aqueous solution is heated at 200°C for 1 minute to cause the sulfonated water-soluble organic polymer resin to react with the crosslinking agent, thereby forming a base on the surface of the aluminum thin plate. A film was formed.

Next, a water-soluble organic polymer compound (
As C), 5% by weight of sodium acrylate/vinyl acetate copolymer and a low molecular weight organic compound having a carbonyl group (
As B), a hydrophilic film-forming agent containing 5% by weight of glyoxal as a main component is applied, and the fin material with the base film coated with this hydrophilic film-forming agent is heated at 190°C for 1 minute, and then sodium acrylate is applied. - An organic hydrophilic film was formed by reacting vinyl acetate copolymer and glyoxal.

Finally, the thin aluminum plate having the base film and the hydrophilic film was molded to produce fins for a heat exchanger.

Comparative Example 4 For comparison, 50 g/p of polyacrylamide as a water-soluble organic polymer resin into which no sulfonic acid groups have been introduced and 15 g/l of water-soluble polyurethane as a water-soluble organic crosslinking agent were added to the surface of the aluminum thin plate. Except for applying an aqueous solution containing was manufactured.

Evaluation test In order to evaluate the performance of the various heat exchanger fins obtained as described above, the hydrophilicity and water resistant adhesion were measured.
The results obtained are shown in the table below.

Here, hydrophilicity is measured at the initial stage, that is, after the press oil on the surface of the press-molded heat exchanger fins is degreased with a solvent, and at the stage after the running water-drying cycle test. It was measured by measuring the contact angle.

Hydrophilicity evaluation: ◎, contact angle of 20° or less, 20″ to 40°
° is expressed as O. Incidentally, there were no cases where the contact angle exceeded 40°.

Water resistant adhesion is measured in an environment with relative humidity of 70% or more.
The surface of a sample of an aluminum fin for a heat exchanger having a base film and a hydrophilic film was rubbed once with an adhesion test jig (felt), and the appearance was evaluated.

In this evaluation of mold wear resistance, molds that remain unchanged after rubbing with a jig (felt) are ◎, and molds that peel off slightly are O.
It was displayed as . Note that there were no cases of severe peeling or cases of complete peeling.

As is clear from the above table, the heat exchanger fins of Examples 1 to 4, which have a base film with sulfonic acid groups (-8O3H) introduced into the surface by the method of the present invention and a specific hydrophilic film, are of the comparative example. Compared to fins 1 to 4, the initial hydrophilicity is almost the same, but the hydrophilicity deteriorates less over time.

In addition, in a high humidity environment, the water-resistant adhesion between the hydrophilic film on the surface side and the base film is extremely good. Even if the water glass-containing hydrophilic film is left in an extremely high humidity environment or a strong external force is applied to the water glass-containing hydrophilic film during the pressing process, the water glass-containing hydrophilic film will not fall off. There is no problem of poor appearance or deterioration of hydrophilicity of heat exchangers such as evaporators due to falling off of the water glass-containing hydrophilic film.

Moreover, since the film components of the heat exchanger fins of Examples 1 to 4 of the present invention are relatively soft, there is little wear of the press mold, and the moldability and mold wear resistance are also excellent.

Effects of the Invention As described above, the method for manufacturing heat exchanger fins according to the present invention is based on the method of the first invention, in which a sulfonic acid group (-8o, H) or a salt thereof is introduced onto the surface of an aluminum fin material. An aqueous solution containing the sulfonated water-soluble organic polymer resin and a water-soluble crosslinking agent (inorganic or organic) is applied, and the fin material coated with this aqueous solution is heated to form a sulfonated water-soluble organic polymer resin. The first step is to form a base film on the surface of the aluminum fin material by reacting with the crosslinking agent and the crosslinking agent.
A hydrophilic film-forming agent containing an alkali silicate (A) and a low-molecular-weight organic compound (B) having a carbonyl group as main components is applied to the surface of the base film, and this hydrophilic film-forming agent is applied to the surface of the base film. The Mitsuin material with the base film is heated,
It consists of a second step of forming a hydrophilic film by reacting the alkali silicate (A) with a low molecular weight organic compound (B) having a carbonyl group, and a second step of forming a hydrophilic film.
In the method of the invention, the first step is the same as the first invention, or the hydrophilic film forming agent in the second step is further blended with a water-soluble organic polymer compound (C) to form an alkali silicate (A ), a hydrophilic film-forming agent whose main components are a low-molecular organic compound (B) having a carbonyl group and a water-soluble organic polymer compound (C). In the method of the third invention, the first step is the same as the first invention, but in the second step, a water-soluble organic polymer compound (
C) and a low molecular weight organic compound (B) having a carbonyl group
The organic-based The fins for heat exchangers produced by the methods of the first to third inventions of the present invention all have extremely excellent hydrophilic properties; There is little deterioration over time.

Furthermore, even in a high humidity environment, the water resistant adhesion between the hydrophilic film on the surface side and the base film is extremely good.

Therefore, for example, even when alkali silicate (A), that is, water glass is used as a component of the hydrophilic film in the methods of the first and second inventions of the present invention, it may be left in an extremely high humidity environment, or Even if a single external force is applied to the water glass-containing hydrophilic film during the pressing process,
The water glass-containing hydrophilic film does not peel off, and therefore, there is no problem of poor appearance or hydrophilic deterioration of heat exchangers such as evaporators due to the falling off of the water glass-containing hydrophilic film. play.

In the first aspect of the present invention, in the second step, the alkali silicate (A) and the low molecular weight organic compound (B) having a carbonyl group react to form a three-dimensional insoluble silicic acid. A salt film is formed, but at this time, the low molecular weight organic compound (B) is incorporated into the three-dimensional network polymer of the silicate, so a stable silicate film is formed and the hydrophilicity becomes even better. At the same time, the flexibility of the film increases.

Further, in the second invention of the present invention, in the second step, a water-soluble organic polymer compound (C) is further added to the hydrophilic film forming agent in the second step of the first invention. The organic polymer compound (C) is further incorporated into the three-dimensional silicate polymer, further increasing the hydrophilicity and flexibility of the film.

In addition, in the method of the third aspect of the present invention, since the alkali silicate (A) is not used as a component of the hydrophilic film, there is less wear on the press mold, and the moldability and mold wear resistance are excellent. There is.

It should be noted that water droplets adhering to the fins produced by the methods of the first to third aspects of the present invention immediately lose their shape, spread as a film on the surface of the fins, and are removed by flowing down. Water remaining on the fins forms a thin film due to surface tension, so this does not impede ventilation. Therefore, a heat exchanger with high heat exchange efficiency can be obtained without increasing ventilation resistance due to adhesion of water droplets.

Specification (full text amended) July 9, 1991 1. Indication of the case 1990 Patent Application No. 49733 2. Name of the invention 3. Person making the amendment Relationship with the case Patent applicant address Sakai City 6-224 Kaizancho Name: Showa Aluminum Co., Ltd. 4, Agent: Month, Day 6, 1998 Number of claims reduced by amendment, Name of invention Manufacture of heat exchanger fins having a base film with excellent water-resistant adhesion Method 2, claims (1) Applying an aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-3o3H) or a salt thereof has been introduced and a water-soluble crosslinking agent to the surface of an aluminum fin material. a first step of forming a base film on the surface of the aluminum fin material by heating the fin material coated with the aqueous solution and causing the sulfonated water-soluble organic polymer resin to react with the crosslinking agent; Alkali silicate (
A) and a low molecular weight organic compound having a carbonyl group (B
) is applied as a main component, and the fin material with the base film coated with this hydrophilic film-forming agent is heated to form a low-molecular organic material having an alkali silicate (A) and a carbonyl group. A method for manufacturing a fin for a heat exchanger having a base film with excellent water-resistant adhesion, which comprises a second step of forming a hydrophilic film by reacting with a compound (B).

(2) An aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-S03H) or its salt has been introduced and a water-soluble crosslinking agent is applied to the surface of the aluminum fin material, and this aqueous solution is applied. The first step is to form a base film on the surface of the aluminum fin material by heating the fin material and reacting the sulfonated water-soluble organic polymer resin with the crosslinking agent. Silicates (
A), a hydrophilic film-forming agent whose main components are a low-molecular organic compound (B) having a carbonyl group and a water-soluble organic polymer compound (C) is applied, and a base film coated with this hydrophilic film-forming agent. The attached fin material is heated to form an alkali silicate (A) and a low molecular weight organic compound (B) having a carbonyl group.
) and a water-soluble organic polymer compound (C) to form a hydrophilic film.

3. Detailed Description of the Invention Field of Industrial Application This invention relates to a method of manufacturing a fin for a heat exchanger having a base film with excellent water-resistant adhesion.

In this specification, aluminum includes aluminum and aluminum alloys.

BACKGROUND OF THE INVENTION Conventionally, various techniques have been proposed for surface treatment of aluminum fin materials for heat exchangers. For example, conventionally, a method has been known in which a surface-treated fin material with excellent corrosion resistance, moldability, and heat yellowing resistance is produced by surface-treating aluminum fin material using a treatment agent containing a synthetic resin and a metal-containing compound. (For example, JP-A-62-2
(See Publication No. 47866).

Conventionally, after performing a base treatment to contain a hardening agent that makes water glass (alkali silicate) insoluble in the organic polymer resin constituting the base film, the fin material with the base film is treated with an aqueous solution of silicate. A hydrophilic treatment method is known.

Problem to be Solved by the Invention However, when a water glass film is formed on a base film mainly composed of an organic polymer resin as in the conventional method, it may be left in an extremely humid environment, or the pressing process may be difficult. When an external force is applied to the water glass film, the water glass film gradually falls off, leading to problems such as poor appearance and deterioration of hydrophilicity of heat exchangers such as evaporators. There was also the problem that there was a concern that the press mold would be worn out by the pieces of water glass that fell off.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to achieve extremely good adhesion (water-resistant adhesion) between the hydrophilic film on the surface side and the base film even in a high humidity environment, and to achieve excellent Hydrophilicity can be maintained for a long period of time, and therefore, water droplets that adhere to the fins immediately spread out into a film and are removed by flowing down, and the heat exchange efficiency is greatly improved without increasing ventilation resistance due to the adhesion of water droplets. In addition to increasing,
It is an object of the present invention to provide a method for manufacturing a fin for a heat exchanger having a base film having good moldability, little wear of a press die, and excellent water-resistant adhesion.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention first provides a method for manufacturing heat exchanger fins having a base film with excellent water-resistant adhesion according to the first invention. To,
An aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (S03H) or its salt has been introduced and a water-soluble crosslinking agent (inorganic or organic) is applied, and the fin material coated with this aqueous solution is heated. The first step is to form a base film on the surface of the aluminum fin material by reacting the sulfonated water-soluble organic polymer resin with a crosslinking agent. ) and a low-molecular-weight organic compound (B) having a carbonyl group are applied as main components, and the fin material coated with the base film coated with the hydrophilic film-forming agent is heated to form an alkali silicic acid. Salt (A) and low molecular weight organic compound having a carbonyl group (B)
A second layer that forms a hydrophilic film by reacting with
It is characterized by being more closely related to the process.

Further, the method for producing a heat exchanger fin according to the second aspect of the present invention includes forming a base film by reacting a water-soluble organic polymer resin into which a sulfonic acid group (-8o3H) or a salt thereof is introduced with a crosslinking agent. The first step is the same as in the first invention, but a water-soluble organic polymer compound (C) is further added to the hydrophilic film-forming agent in the second step to form an alkali silicate (A). , a low-molecular organic compound having a carbonyl group (B
) and a water-soluble organic polymer compound (C) as main components to form a hydrophilic film using a hydrophilic film forming agent.

In the above, the aluminum fin material can be processed and processed in the form of a flat plate having the required length, but it is particularly preferable to process and process it continuously in the form of a coil.

In the first step of the method of the present invention, examples of the organic polymer resin into which the sulfonic acid group (-SO3H) is to be introduced include the following.

(i) Vinyl polymers such as vinyl acetate, vinyl chloride, and vinylidene chloride, and their copolymers, into which sulfonic acid groups have been introduced.

(11) Acrylic polymers and copolymers thereof, such as acrylic acid, methacrylic acid and their esters, and acrylamide, into which sulfonic acid groups have been introduced.

(iii) Styrene-based, olefin-based, urethane-based,
Polyester, alkyd, and epoxy polymers and their copolymers with sulfonic acid groups introduced.

(1v) A synthetic rubber-based material into which a sulfonic acid group has been introduced.

In addition, in this specification, for convenience, synthetic rubber into which a sulfonic acid group has been introduced is included in the water-soluble organic polymer resin into which a sulfonic acid group has been introduced.

Here, there are generally the following two methods for introducing a sulfonic acid group into the above polymer.

First, a method of polymerizing or copolymerizing a monomer having a sulfonic acid group.

Here, examples of the monomer having a sulfonic acid group include vinylsulfonic acid, styrenesulfonic acid, and 2-acrylamide-2methylpropanesulfonic acid.

Second, a method in which a sulfonating agent is applied to a polymer or copolymer to later introduce a sulfonic acid group.

Here, as the sulfonating agent, salts of bisulfite such as sodium, potassium, and ammonium salts of bisulfite are generally used, but in some cases, sulfite gas may be used to adjust the bisulfite in the system. , it can also be subjected to a reaction.

In the reaction, it is preferable to use an oxide as a reaction accelerator, such as peroxides such as potassium persulfate, potassium nitrate, sodium nitrate,
Examples include nitrates such as ammonium nitrate, hydrogen peroxide, oxygen, and organic peroxides.

The proportion of the sulfonating agent used in the reaction may be selected appropriately depending on the desired product, or, since the reaction generally proceeds quantitatively, it is sufficient to use a theoretical amount or a slight excess amount. be.

In addition, it is appropriate that the pH during the sulfonation reaction be 8 or less, preferably 7 to 5; if the pH value becomes too large, the reactivity will be inhibited, and on the other hand, if the pH value is too small, the sulfonation product will be is not preferred because of its poor solubility.

The reaction temperature is usually room temperature to 1SO℃, and the reaction time is 1
~25 hours, but this is of course not limiting.

The content of sulfonic acid groups (-8O3H) in the organic polymer resin varies depending on the conditions of the sulfonation reaction, the amount of organic polymer resin used in the reaction, etc. It is preferred that about 50%, especially about 5 to 40%, be sulfonated.

The weight average molecular weight of the organic polymer resin before sulfonation is 1
,000-200,000, preferably 5,000-200,000
I(10, (IH.

Note that after producing the organic polymer resins or synthetic rubbers of (i) to (l) above, they are sulfonated using the sulfonating agent described above, but the components of these organic polymer resins or synthetic rubbers are In some cases, the sulfonated component is sulfonated in advance using a sulfonating agent, and then the sulfonated component is polymerized.

The sulfonic acid group (-8o3H) of the above water-soluble organic polymer resin
) may be present in the form of salt. As the cation constituting the salt of the sulfonic acid group of such a water-soluble organic polymer resin, for example, alkali metals, alkaline earth metals, ammonium, amines, etc. are used.

Here, examples of alkali metals include sodium and potassium, and examples of alkaline earth metals include calcium and magnesium.

Examples of amines include alkylamines such as methylamine, ethylamine, propylamine, dimethylamine, diethylamine, triethylamine, and butylamine, and polyamines such as ethylenediamine and diethylenetriamine.

Specifically, the water-soluble organic polymer resin into which the sulfonic acid group (S 03H) or a salt thereof is introduced is a copolymer of acrylamide/2-acrylamide-2methylpropanesulfonic acid, and sodium styrene sulfonate. - Examples include acrylamide copolymers, sulfonated polyacrylamide, sulfonated polystyrene, etc.

Further, the water-soluble cross-linking agent used in the first step of the method of this invention includes a water-soluble inorganic cross-linking agent and a water-soluble organic cross-linking agent, and either one of the two may be used, or both may be used in combination. You may do so.

These water-soluble crosslinking agents have the above-mentioned sulfonic acid group (-8O3
An appropriate one is used depending on the type of water-soluble organic polymer resin into which H) or its salt is introduced.

That is, for example, in the case of a water-soluble organic polymer resin into which a sulfonic acid group (-3O3H) or a salt thereof has been introduced, or an organic polymer resin having active hydrogen, two or more isocyanates are used as a water-soluble crosslinking agent. A compound that can react with active hydrogen, such as a group, an aziridyl group, a glycidyl group, or a methylol group, is used.

Further, when the water-soluble organic polymer resin is an oligomer or organic polymer resin having an unsaturated group, an unsaturated compound copolymerizable with the oligomer or organic polymer resin is used as the water-soluble crosslinking agent.

Furthermore, when the water-soluble organic polymer resin is an organic polymer resin made of a water-soluble polymer or copolymer containing oxygen or nitrogen, a metal compound that can form a complex compound with these is used as a water-soluble crosslinking agent. Use. In this case, the crosslinking agent acts as a crosslinking insolubilizer. In particular, it is preferable to use a metal compound having a coordination number of 4 or more, including Cr, Ti, etc.
, AI, and Zn compounds are effective.

In the first step of the method of this invention, the blending ratio of the water-soluble organic polymer resin into which the sulfonic acid group (-8O3H) or its salt has been introduced and the water-soluble crosslinking agent (inorganic type, organic type) is The amount of the water-soluble crosslinking agent is 0.1 to 5 parts by weight per 1 part by weight of the organic polymer resin.

Here, if the water-soluble crosslinking agent is less than 0.1 part by weight per 1 part by weight of the water-soluble organic polymer resin into which a sulfonic acid group (-8o3H) or its salt has been introduced, the crosslinking density during heat drying will be low. 5, the base film is not sufficiently formed into a film, and
If the amount exceeds 1 part by weight, the life of the base treatment liquid (pot life) will be shortened, which is not preferable.

Note that the water-soluble organic polymer resin into which a sulfonic acid group (-8o3H) or a salt thereof has been introduced and the water-soluble crosslinking agent are used after being diluted with water. The dilution ratio must be determined by taking into consideration the hydrophilicity of the base film, film thickness, and workability.

In order to treat the surface of the aluminum fin material with an aqueous solution of the above-mentioned compound, the aluminum fin material may be applied by spraying, roll coating, flow coating, or by immersing the aluminum fin material in the aqueous solution.

The aluminum fin material after being treated with an aqueous solution is 10
at a temperature of 0 to 2 SO °C, preferably 150 to 230 °C,
It is heated and dried for 5 seconds to 20 minutes to form a hydrophilic base film on the surface.

Here, if the heat drying temperature is less than 100°C, the composition will not form a film sufficiently, and if it exceeds 2SO°C, further heating will not only have no effect but will also have a negative effect on the aluminum material.

If the heat drying time is less than 5 seconds, the composition will not form a film sufficiently, and if it exceeds 20 minutes, productivity will decrease. When the heating drying temperature is high, such as 1SO to 2SO°C, the drying time may be as short as 30 seconds to 1 minute, but when the temperature is low, the drying time needs to be increased. If heat drying is insufficient, the formulation will not form a film sufficiently.

Further, the hydrophilic base film is formed on the surface of the aluminum fin material to a thickness of 10 μm or less, preferably 0.02 to 2 μm. Here, if the thickness of the base film exceeds 10 μm, it is not preferable because it takes a long time to dry and the heat exchange performance deteriorates.

Next, the alkali silicate (A) in the second step of the present invention constitutes the main component for imparting hydrophilicity to the film, and is 51027M20 (where M is lithium, sodium, potassium, etc.). It is necessary to use a metal having a ratio of 1 or more (meaning an alkali metal).

In particular, it is preferable to use an alkali silicate having a SiO/M20 of 2 to 5.

Furthermore, the low-molecular organic compound (B) in the second step of the present invention is a low-molecular organic compound having a carbonyl group (>C=O) in the molecule, and this is an alkali silicate (
This stabilizes the film formed by A), improves its hydrophilicity, and imparts flexibility to the film.

Specific examples of such low-molecular organic compounds (B) include aldehydes, esters, and amides.

Here, as the aldehydes, formaldehyde, acetaldehyde, glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, furfuraldialdehyde, etc. are used.

Examples of esters include fatty acid esters of monohydric alcohols such as methyl formate, ethyl acetate, methyl acetate, butyl acetate, amyl acetate, and methyl propionate, as well as ethylene glycol diacetate, glycerine triacetate, and ethylene glycol dipropionate. Fatty acid esters of polyhydric alcohols such as esters, intramolecular esters such as γ-butyrolactone, and-caprolactone,
Also, ethylene glycol monoformate, ethylene glycol monoacetate, ethylene glycol monopropionate, glycerin monoformate, glycerin monoacetate, glycerin monopropionate, glycerin diformate, glycerin diacetate, sorbitol monoformate , sorbitol monoacetate, and polyhydric alcohol partial esters such as glycose acid monoacetate, and polybasic acids such as dimethyl succinate and dimethyl maleate.
Hydrolic alcohol esters and cyclic carbonates such as ethylene carbonate, propylene carbonate, and glycerin carbonate are used.

Further, as the amides, formamide, dimethylformamide, acetamide, dimethylacetamide, propionamide, butyramide, acrylamide, malondiamide, pyrrolidone, caprolatam, and the like are used.

Among the low-molecular organic compounds (B), water-soluble compounds are preferably used in order to perform uniform treatment,
In particular, it is preferred to use aldehydes and esters.

Next, in the second step of the present invention, the water-soluble organic polymer compound (C) has a hydrophilic coating formed from an alkali silicate (A) and a low molecular weight organic compound (B) having a carbonyl group. This further improves flexibility and flexibility.

Specifically, such water-soluble organic polymer compounds (C) include polysaccharide-based natural polymers, water-soluble protein-based natural polymers, anionic, nonionic, or cationic addition-polymerized water-soluble synthetic polymers. , and polycondensation water-soluble polymers.

Here, the polysaccharide natural polymers include soluble starch,
Carboxymethyl cellulose, hydroxyethyl cellulose, guar gum, gum tragacanth, xanthan gum, sodium alginate, etc. are used. Gelatin or the like is used as the water-soluble protein-based natural polymer.

Examples of anionic or nonionic addition polymer water-soluble polymers include polyacrylic acid, sodium polyacrylate, polyacrylamide, partial hydrolysates thereof, polyvinyl alcohol, polyhydroxyethyl amarylate, polyvinylpyrrolidone, and acrylic acid copolymers. and maleic acid copolymers and their alkali metal, organic amine and ammonium salts. Furthermore, water-soluble synthetic polymers modified by carboxymethylation or sulfonation of the above-mentioned addition polymerized water-soluble synthetic polymers can also be used.

Examples of cationic addition-polymerized water-soluble synthetic polymers include polyethyleneimine, Mannich-modified compounds of polyacrylamide, diacryldimethylaluminum chloride,
Polyalkylamino (meth)acrylates such as polyvinylimidacillin and dimethylaminoethyl acrylate polymers are used.

Polycondensation water-soluble synthetic polymers include polyalkylene polyols such as polyoxyethylene glycol and polyoxyethylene oxypropylene glycol, polycondensates of epichlorohydrin and polyamines such as ethylenediamine or hexamethyldiamine, and water-soluble polyethers. A water-soluble polyurethane resin obtained by polycondensation of polyisocyanate, polyhydroxymethylurea resin, polyhydroxymethylmelamine resin, etc. are used.

Among the water-soluble organic polymer compounds (C), it is preferable to use an anionic addition-polymerized water-soluble polymer having a carboxylic acid or a carboxylic acid group, particularly polyacrylic acid, acrylic acid copolymer, maleic acid, etc. Preference is given to using acid copolymers and their alkali metal salts. Here, the acrylic acid copolymer and maleic acid copolymer include copolymers of acrylic acid and maleic acid, as well as acrylic acid or maleic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, Preferably, a copolymer with hydroxyethyl methacrylate, itaconic acid, vinyl sulfonic acid, or acrylamide is used.

In the second step of the first invention and the second invention, the blending ratio of the alkali silicate (A), the low molecular organic compound having a carbonyl group (B), and the water-soluble organic polymer compound (C) is , as follows.

First, in the case of (A) + (B), alkali silicate (A
) A low molecular weight organic compound (B) having a carbonyl group is blended in an amount of 0.1 to 5 parts by weight per 1 part by weight.

Next, in the case of (A) + (B) + (C), 0.1 to 5 parts by weight of a low molecular weight organic compound (B) having a carbonyl group is added to 1 part by weight of the alkali silicate (A). part by weight, and a water-soluble organic polymer compound in a proportion of 0.01 to 5 parts by weight.

In the above, if the amount of the alkali silicate (A) in the hydrophilic film forming agent is small, a sufficient hydrophilic film will not be formed on the surface of the base film. On the other hand, if the amount is too large, the film becomes too hard, resulting in poor moldability and mold wear resistance.

Further, if the amount is less than 0.1 part by weight per 1 part by weight of the low molecular weight organic compound (B) having a carbonyl group or the alkali silicate (A), the effect of adding the low molecular weight organic compound (B) will not be exhibited. Moreover, if it exceeds 5 parts by weight, the amount of alkali silicate (A) will be relatively small, so that sufficient hydrophilicity will not be exhibited.

The water-soluble organic polymer compound (C) is an alkali silicate (A
) If the amount is less than 0.01 part by weight per 1 part by weight, the effect of adding the polymer compound (C) will not appear, and if it exceeds 5 parts by weight, the formed film will be easily eluted into water, The sustained effect of hydrophilicity is reduced.

In the first and second inventions, the alkali silicic acid m (A), the low molecular organic compound having a carbonyl group (B), and the water-soluble polymer compound (C) are used after being diluted with water. . The dilution ratio must be determined in consideration of the hydrophilicity, film thickness, and workability of the film.

As mentioned above, the surface of the aluminum fin material with a base film made of a water-soluble organic polymer resin into which a sulfonic acid group (-3o3H) or a salt thereof has been introduced and modified with a water-soluble crosslinking agent is coated with the above (A). + (B) or (A)
+ (B) + (C) To treat with an aqueous solution of a hydrophilic treatment agent, apply by spraying, brushing, roll coating, flow coating, or applying in an aqueous solution as in the case of the above-mentioned base treatment. All you have to do is immerse the aluminum fin material in the water.

The aluminum fin material after being treated with an aqueous solution of a hydrophilic treatment agent has a temperature of 100 to 2SO℃, preferably 150 to 23℃.
It is heated and dried at a temperature of 0° C. for 5 seconds to 30 minutes to form a hydrophilic film on the surface.

Here, if the heat drying temperature is less than 100°C, the hydrophilic treatment agent will not form a film sufficiently, and if it exceeds 2SO°C,
Further heating will not only have no effect, but will also have a negative effect on the aluminum material. In addition, if the heating drying time is less than 5 seconds, the hydrophilic treatment agent will not form a film sufficiently, and the
If it exceeds 1 minute, productivity will decrease. If the heat drying temperature is as high as 1SO~2SO℃, the drying time is 5 seconds>
The drying time may be as short as 1 minute, but if the temperature is low, it may be necessary to lengthen the drying time.

If heat drying is insufficient, the hydrophilic treatment agent will not form a film sufficiently.

Also, the above (A) + (B) or (A) + (B) + (
The hydrophilic film of each component in C) has a surface of 0.1
It is formed at a rate of ~10g/m2, preferably 0.5~3g/m2.

Here, if the film is 0.1 g/m2 or more, the initial hydrophilicity is good, but in order to maintain even better hydrophilicity, it is necessary to form a film of 0.5 g/m2 or more. preferable. Moreover, if the film exceeds 10 g/m2, it takes a long time to dry and has an adverse effect on press formability, which is not preferable.

The aqueous solution of the hydrophilic treatment agent may contain conventionally known additives, such as inorganic rust inhibitors such as sodium nitrite, sodium polyphosphate, and sodium metaborate, benzoic acid and its salts, and paranitrobenzoic acid. and its salt,
Of course, an organic rust preventive agent such as cyclohexylamine carbonate or benzotriazole may be added.

Finally, the aluminum fin material having the base film and hydrophilic film obtained as described above is subjected to nibless processing to produce fins for a heat exchanger.

Here, press processing is a process for forming a plate-shaped fin having a tube insertion hole from the above-mentioned coated fin material, and includes overhang processing, drawing processing, punching processing, curling processing, and This includes ironing, etc. to tighten and heighten the cylindrical rising wall around the tube insertion hole.

Furthermore, when the aluminum fin material is a coil material, the shearing process that is performed subsequent to these processes to cut the fin material into a predetermined length is also included.

The heat exchanger fins having the sulfonic acid group-introduced base film and the specific hydrophilic film manufactured by the methods of the first and second inventions of the present invention have relatively soft film components, so press mold wear does not occur. It also has excellent moldability and mold abrasion resistance, and can be pressed extremely smoothly, making it possible to efficiently produce fins for heat exchangers.

Moreover, the heat exchanger fins produced by the method of the present invention all have extremely excellent hydrophilicity, and even in high humidity environments, the water-resistant adhesion between the hydrophilic film on the surface side and the base film is extremely high. In good condition. Therefore, for example, even in the case of the first invention and the second invention, in which alkali silicate (Δ), that is, water glass is used as a component of the hydrophilic film, water glass may be left in an extremely high humidity environment, or water glass may be used in the pressing process. Even if a single external force is applied to the water glass-containing hydrophilic film, the water glass-containing hydrophilic film will not fall off, and there will be no problems with appearance defects or hydrophilic deterioration of heat exchangers such as evaporators. It is.

Example Next, examples of the present invention will be described together with comparative examples.

Example 1 As an aluminum fin material, thickness 0.2cm, width 50mm
mm, and length 100mm JISA-1100H2
No. 4 aluminum thin plate was used.

A sulfonic acid group (-3o
50g/liter of acrylamide/2-acrylamide-2methylpropanesulfonic acid copolymer as a water-soluble organic polymer resin containing 3H), 2g/liter of chromic anhydride and 25g of zirconium fluoride as a water-soluble inorganic crosslinking agent. /liter, and heated the fin material coated with this aqueous solution at 200°C for 15 minutes to cause the sulfonated water-soluble organic polymer resin to react with the crosslinking agent. A base film was formed on the surface.

Next, alkali silicate (A) 2
Weight %, low molecular weight organic compound (B) having a carbonyl group
A hydrophilic film-forming agent containing 2% by weight of γ-butyrolactone as a water-soluble organic polymer compound (C) and 2% by weight of sodium salt of an acrylic acid/vinyl acetate copolymer as a water-soluble organic polymer compound (C) is applied. The fin material with the base film coated with the film-forming agent was heated at 200°C for 1 minute to form the alkali silicate (A) and the low molecular weight organic compound (B) a water-soluble organic polymer compound (B) having a carbonyl group. A hydrophilic film was formed by reacting with C).

Finally, the aluminum thin plate having the base film and hydrophilic film was molded to produce heat exchanger fins.

In addition, as the alkali silicate (A), SiO/
One with a Na2O ratio of 3 was used.

Comparative Example 1 For comparison, 50 g and 7 liters of a copolymer of acrylamide/2-acrylamide-ethylamine was added to the surface of the aluminum thin plate as a water-soluble organic polymer resin in which no sulfonic acid groups were introduced, and as a water-soluble crosslinking agent. Chromic anhydride 2g/liter and fluorinated zirconium 25g/liter
A thin aluminum plate having a base film in which no sulfonic acid groups have been introduced and a hydrophilic film is formed by the same operation as in Example 1 above, except that an aqueous solution containing A fin for an exchanger was manufactured.

Example 2 Same as in Example 1 above, on the surface of the aluminum thin plate,
In the same manner as in Example 1, the sulfonic acid group (-3o3H
) was introduced into the base film.

Next, alkali silicate (A
) 5% by weight, a low molecular weight organic compound having a carbonyl group (
As B), a hydrophilic film-forming agent containing 5% by weight of γ-butyrolactone as a main component is applied, and the fin material coated with the base film coated with this hydrophilic film-forming agent is heated at 200°C for 1 minute to form an alkali film. A hydrophilic film was formed by reacting the silicate with γ-butyrolactone. and,
A thin aluminum plate having this base film and a hydrophilic film was molded to produce a fin for a heat exchanger.

Comparative Example 2 For comparison, 50 g/liter of an acrylamide/2-acrylamide-ethylamine copolymer and a water-soluble crosslinking agent were added to the surface of the aluminum thin plate as a water-soluble organic polymer resin in which no sulfonic acid groups were introduced. as chromic anhydride 2g/liter and fluoridated zirconium 25g/liter
A thin aluminum plate having a base film in which no sulfonic acid groups were introduced and a hydrophilic film was formed by the same operation as in Example 2 above, except for applying an aqueous solution containing 1. A fin for a heat exchanger was manufactured.

Evaluation test In order to evaluate the performance of the various heat exchanger fins obtained as described above, the hydrophilicity and water resistant adhesion were measured.
The results obtained are shown in the table below.

Here, hydrophilicity is measured at the initial stage, that is, after the press oil on the surface of the press-molded heat exchanger fins is degreased with a solvent, and at the stage after the running water-drying cycle test. It was measured by measuring the contact angle.

Hydrophilicity evaluation: ◎, contact angle of 20° or less, 20° to 40°
° is indicated as ○. Incidentally, there were no cases where the contact angle exceeded 40°.

Water resistant adhesion is measured in an environment with relative humidity of 70% or more.
The surface of a sample of an aluminum fin for a heat exchanger having a base film and a hydrophilic film was rubbed once with an adhesion test jig (felt), and the appearance was evaluated.

In this evaluation of mold wear resistance, after rubbing with a jig (felt), those with no change are ◎, and those with slight peeling are ○.
It was displayed as . Note that there were no cases of severe peeling or cases of complete peeling.

As is clear from the above table, the heat exchanger fins of Examples 1 and 2, which have a base film on which sulfonic acid groups (-SO3H) are introduced by the method of the present invention and a specific hydrophilic film, are the same as those of the comparative example. Compared to fins Nos. 1 and 2, the initial hydrophilicity was similar, but the hydrophilicity deteriorated less over time.

In addition, in a high humidity environment, the water-resistant adhesion between the hydrophilic film on the surface side and the base film is extremely good. For example, when alkali silicate (A) or water glass is used as a component of the hydrophilic film. Even if the water glass-containing hydrophilic film is left in an extremely high humidity environment, or even if a single external force is applied to the water glass-containing hydrophilic film during the pressing process, the water glass-containing hydrophilic film will not fall off. There is no problem of poor appearance or deterioration of hydrophilicity of heat exchangers such as evaporators due to such falling off of the water glass-containing hydrophilic film.

Furthermore, since the heat exchanger fins of Examples 1 and 2 of the present invention have relatively soft coating components, there is little wear on the press mold, and they are also excellent in moldability and mold wear resistance.

Effects of the Invention As described above, the method for manufacturing heat exchanger fins according to the present invention is based on the method of the first invention, in which a sulfonic acid group (-8o3H) or a salt thereof is introduced onto the surface of an aluminum fin material. Water-soluble organic polymer resin and water-soluble crosslinking agent (
An aluminum fin material is produced by applying an aqueous solution containing (inorganic and organic) and heating the fin material coated with the aqueous solution to cause the sulfonated water-soluble organic polymer resin to react with the crosslinking agent. The first step is to form a base film on the surface of the
A hydrophilic film-forming agent containing an alkali silicate (A) and a low-molecular-weight organic compound (B) having a carbonyl group as main components is applied to the surface of the base film, and this hydrophilic film-forming agent is applied to the surface of the base film. The fin material with the base film is heated,
It consists of a second step of forming a hydrophilic film by reacting the alkali silicate (A) with a low molecular weight organic compound (B) having a carbonyl group, and a second step of forming a hydrophilic film.
In the method of the invention, the first step is the same as the first invention, or the hydrophilic film forming agent in the second step is further blended with a water-soluble organic polymer compound (C) to form an alkali silicate (A ), a hydrophilic film forming agent whose main components are a low-molecular organic compound (B) having a carbonyl group and a water-soluble organic polymer compound (C) is used to form a hydrophilic film. The heat exchanger fins manufactured by the methods of the first invention and the second invention both have very excellent hydrophilicity, and their hydrophilicity hardly deteriorates over time. Furthermore, even in a high humidity environment, the water resistant adhesion between the surface side hydrophilic film and the base film is extremely good.

Therefore, for example, even when alkali silicate (A), that is, water glass is used as a component of the hydrophilic film in the methods of the first and second inventions of the present invention, it may be left in an extremely high humidity environment, or Even if an external force is applied to the water glass-containing hydrophilic film during the pressing process,
The water glass-containing hydrophilic film does not peel off, and therefore, there is no problem of poor appearance or hydrophilic deterioration of heat exchangers such as evaporators due to the falling off of the water glass-containing hydrophilic film. play.

In the first aspect of the present invention, in the second step, the alkali silicate (A) and the low molecular weight organic compound (B) having a carbonyl group react to form a three-dimensional insoluble silicic acid. A salt film is formed. At this time, the low molecular organic compound (B) is incorporated into the three-dimensional network polymer of the silicate, so a stable silicate film is formed and the hydrophilicity is further improved. At the same time, the flexibility of the film increases.

Further, in the second invention of the present invention, in the second step, the water-soluble organic polymer compound (C) is further added to the hydrophilic film forming agent in the second step of the first invention. The organic polymer compound (C) is further incorporated into the three-dimensional silicate polymer, further increasing the hydrophilicity and flexibility of the film.

It should be noted that water droplets adhering to the fins produced by the methods of the first and second aspects of the present invention immediately lose their shape, spread as a film on the surface of the fins, and are removed by flowing down. Water remaining on the fins forms a thin film due to surface tension, so this does not impede ventilation. Therefore, a heat exchanger with high heat exchange efficiency can be obtained without increasing ventilation resistance due to adhesion of water droplets.

that's all

Claims (3)

[Claims] (1) Applying an aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-SO_3H) or its salt has been introduced and a water-soluble crosslinking agent to the surface of an aluminum fin material,
A first step of forming a base film on the surface of the aluminum fin material by heating the fin material coated with this aqueous solution and causing the sulfonated water-soluble organic polymer resin to react with the crosslinking agent; on the surface of the alkali silicate (A) and a low molecular weight organic compound having a carbonyl group (
A hydrophilic film-forming agent containing B) as a main component is applied, and the fin material with a base film coated with this hydrophilic film-forming agent is heated to form a low-molecular-weight material having an alkali silicate (A) and a carbonyl group. By reacting with the organic compound (B),
A method for manufacturing a fin for a heat exchanger having a base film with excellent water-resistant adhesion, comprising a second step of forming a hydrophilic film. (2) Applying an aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-SO_3H) or its salt has been introduced and a water-soluble crosslinking agent to the surface of an aluminum fin material,
A first step of forming a base film on the surface of the aluminum fin material by heating the fin material coated with this aqueous solution and causing the sulfonated water-soluble organic polymer resin to react with the crosslinking agent; On the surface of the alkali silicate (A), a low molecular weight organic compound having a carbonyl group (B)
A hydrophilic film-forming agent containing a water-soluble organic polymer compound (C) as a main component is applied, and the fin material with a base film coated with this hydrophilic film-forming agent is heated. ) and low-molecular organic compounds with carbonyl groups (
A second step of forming a hydrophilic film by reacting B) with a water-soluble organic polymer compound (C),
A method for manufacturing a heat exchanger fin having a base film with excellent water-resistant adhesion. (3) Applying an aqueous solution containing a water-soluble organic polymer resin into which a sulfonic acid group (-SO_3H) or its salt has been introduced and a water-soluble crosslinking agent to the surface of an aluminum fin material,
A first step of forming a base film on the surface of the aluminum fin material by heating the fin material coated with this aqueous solution and causing the sulfonated water-soluble organic polymer resin to react with the crosslinking agent; An aqueous solution containing a water-soluble organic polymer compound (C) and a low-molecular organic compound (B) having a carbonyl group is applied to the surface of the fin material, and the fin material with the base film coated with this aqueous solution is heated. A heat exchanger having a base film with excellent water-resistant adhesion, consisting of a second step of forming an organic hydrophilic film by reacting a water-soluble organic polymer compound (C) and a low-molecular organic compound (B). How to make dexterous fins.