JPH06228459A - Composition for hydrophilicization method for hydrophilicization using the same - Google Patents

Abstract

PURPOSE:To provide a fin material excellent in hydrophilicity sustainability and corrosion resistance. CONSTITUTION:The composition comprising (A) water-dispersible fine silica particles, (B) a water-soluble or water-dispersible organic resin and (C) an onium group-contg. hydrolyzable silane compound, consisting mainly of an inorganic- organic composite resin with the weight ratio A/B of (10:90) to (95:5) on a solid basis and the component C accounting for 0.5-20wt.% of a total of 100wt.%, on a solid basis, of the components A and B. The other objective method for hydrophilicizing a fin material is such that a fin material made of metallic aluminum or an aluminum alloy is coated with the above composition followed by curing to make a cured coating film 0.1-5mum thick.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophilic treatment composition having excellent hydrophilicity lasting property and a fin material hydrophilic treatment method using the same.

[0002]

2. Description of the Related Art In a heat exchanger of an air conditioner, condensed water generated during cooling forms water droplets to form a water bridge between fins and narrows an air passage, resulting in increased ventilation resistance. Problems such as power loss, noise, and water droplets will occur. As a measure for preventing such a phenomenon, for example, a surface of an aluminum fin material (hereinafter referred to as a fin material) is hydrophilized to prevent formation of water drops and bridges due to water drops.

Examples of the hydrophilic treatment method include (1) a boehmite treatment method known as a surface treatment method for aluminum; (2) a method for applying water glass represented by the general formula mSiO ₂ / nNa ₂ O (for example, Japanese Patent Publication 55-134
No. 7, JP-A-58-126989); (3) Paints in which silica, water glass, aluminum hydroxide, calcium carbonate, titania, etc. are mixed with an organic resin, or a surfactant is used in combination with these paints. Method of applying the above-mentioned paint (for example, Japanese Patent Publication No. 57-46000,
Japanese Patent Publication No. 59-8372, Japanese Patent Publication No. 62-61078
JP-A-59-229197, JP-A-61
No. 225044, etc.); (4) A method of applying a coating material comprising an organic-inorganic (silica) composite resin and a surfactant (see JP-A-59-170170), and the like. Some of them are already in practical use.

Although the hydrophilization technology of the heat exchanger has been put into practical use as exemplified above, in terms of the persistence of the hydrophilicity of the treated plate (water droplet contact angle, entirely wetted with water), corrosion resistance, odor, etc. There are still problems to be improved.

In particular, in recent years, the space between the fin members has become narrower in order to further reduce the size and weight of the heat exchanger, which requires a high degree of hydrophilicity. ) And (4), the hydrophilicity cannot be sufficiently exerted.

Further, in the boehmite treatment method (1), there is a problem in corrosion resistance, and in addition, there is a problem in press workability because the obtained coating film is hard. Further, (2) the method of applying water glass shows a good hydrophilic sustainability, in which the contact angle of water droplets on the fin material-treated plate is 20 ° or less, but the fin material treated with water glass shows a powdery surface on the treated film over time. And a cement odor or chemical odor scattered during ventilation is generated. Moreover, water glass is hydrolyzed by the condensed water generated during the operation of the heat exchanger, and the surface of the fin material becomes alkaline, so that pitting corrosion easily occurs, and aluminum hydroxide powder (white powder), which is a corrosion product, scatters. It is known that there are environmental problems.

As described above, many techniques for making the fin material of the heat exchanger hydrophilic have been proposed in the past, but they are still insufficient in terms of durability of hydrophilicity and corrosion resistance.

[0008] Therefore, the present inventors
As a result of intensive research to develop a hydrophilization treatment method capable of providing a fin material excellent in terms of corrosion resistance, etc., a composition for hydrophilization treatment containing a specific organic-inorganic composite resin composition as a main component The present invention has been completed by finding that the above problems can be solved by using a product.

[0009]

The present invention thus provides
(A) water-dispersible silica fine particles, (B) water-soluble or water-dispersible organic resin, and (C) onium group-containing hydrolyzable silane compound, and (A) component: solid content of (B) component The weight ratio is within the range of 10:90 to 95: 5, and the total solid content of the components (A) and (B) is 1
It is intended to provide a composition for hydrophilization treatment containing an inorganic-organic composite resin as a main component, wherein the amount of the component (C) is within the range of 0.5 to 20 parts by weight relative to 00 parts by weight.

According to the present invention, a fin material made of aluminum or an aluminum alloy is coated with the above-mentioned hydrophilic treatment composition and cured to form a coating film having a cured coating film thickness of 0.1 to 5 μm. The present invention provides a method for hydrophilizing a fin material, which comprises:

As described above, the hydrophilic treatment composition of the present invention is a composition containing an inorganic-organic composite resin as a main component.

(A) in the above inorganic-organic composite resin
The water-dispersible silica fine particles as a component roughen the coating film, and the silanol groups existing on the silica surface form hydrogen bonds with water, which is useful for imparting hydrophilicity to the coating film. In general, silica has a large amount of odor adsorption, and the silica fine particles exposed in the surface layer in the obtained coating film contribute to the adsorption of odor, but since the silica in the interior portion of the coating film is covered with the organic resin component, its odor Adsorption amount is reduced.

Typical examples of silica fine particles that can be used include water-dispersible silica, so-called colloidal silica, and water-dispersible powdered fumed silica. Colloidal silica can be produced, for example, by sodium removal of water glass (ion exchange method, acid decomposition method, peptization method, etc.), and the primary particle diameter is in the range of 5 to 50 mμ, and usually an aqueous dispersion liquid. Is supplied as
For example, Snowtex 20, the same 30, the same C, the same N, the same AK [all above are manufactured by Nissan Kagaku Co., Ltd.], Cataroid S-20L, the same S-30H, same SN [all above, Catalytic Chemical Industry Co., Ltd.], Adelite AT-20, A
Examples thereof include T-30, AT-20N, and CT-100 [all of which are manufactured by Asahi Denka Co., Ltd.].

The water-dispersible powdered fumed silica generally has a primary particle size of 5 to 5 called dry silica.
Within the range of 50 mμ, those produced by combustion of silicon tetrachloride can be used, Aerosil 130,
Aerosil 200, Aerosil 300, Aerosil 38
0, Aerosil R972, Aerosil R974, Aerosil R811 [all of which are manufactured by Nippon Aerosil Co., Ltd.

These silica fine particles may be used alone or in admixture of two or more. As the organic resin which is the component (B) in the inorganic-organic composite resin,
A water-soluble or water-dispersible resin containing at least one functional group such as a hydroxyl group, a carboxyl group and an amino group in the molecule can be used, and examples thereof include an acrylic resin, a polyester resin, an epoxy resin, a fatty acid or Examples thereof include polybasic acid-modified polybutadiene resin, methylol group-introduced phenol resin, alkanolamine-modified polyurethane resin, polyamidoamine resin, amino resin, polycarboxylic acid resin, polyvinyl alcohol, natural polysaccharides and derivatives thereof. Of these resins, a cationic type or nonionic type resin is more preferable from the viewpoint of stability of the hydrophilic treatment composition.

Water-solubilization or water-dispersion of the above-mentioned organic resin is carried out by water-solubilizing or water-dispersing the resin as it is, or, if necessary, based on a functional group introduced into the resin skeleton, for example, an acidic resin. Achieved by neutralizing with amine compounds, ammonia water, and alkali metal hydroxides, if present, and with basic acids, such as fatty acids such as acetic acid and lactic acid, and mineral acids such as phosphates. can do.

(C) in the inorganic-organic composite resin
The onium group-containing hydrolyzable silane compound as a component is
A silane compound containing a hydrolyzable group bonded to silane and an onium group, and examples thereof include an onium salt represented by the following formula (I).

[0018]

[Chemical 2]

[Wherein R ¹ represents an onium-containing group,
R ² and R ³ are the same or different and each represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, Y represents a hydrolyzable group, X represents a halogen atom or an organic acid carboxylate, and a And each represent 0 or 1, respectively.] In the above formula (I), examples of the onium-containing group represented by R ¹ include an ammonium-containing group, a phosphonium-containing group and a sulfonium-containing group. The ammonium-containing group and the phosphonium-containing group may contain any of secondary, tertiary, and quaternary ammonium or phosphonium, and the sulfonium-containing group may be secondary or tertiary. Any of the above sulfonium may be contained.

Of the above-mentioned onium-containing groups, ammonium-containing groups are particularly preferable, and specifically, the following general formula (I
Those represented by I) are preferred.

[0021]

[Chemical 3] [In the formula, R ⁴ represents an organic group having 8 or more carbon atoms, and R ⁵
And R ⁶ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁷ represents a divalent organic group having 1 to 6 carbon atoms.] In the above formula (II), Examples of the organic group having 8 or more carbon atoms represented by R ⁴ include octyl group, decyl group, undecyl group,
C8 to C30 alkyl group such as octadecyl group; aromatic ring-containing hydrocarbon group such as p-vinylbenzyl group and C8 to C30; β-N-vinylbenzylaminoethyl group and other C8 The nitrogen atom-containing organic group of -30 and the like can be mentioned.

The number of carbon atoms in R ⁵ and R ⁶ is 1
Examples of the alkyl group of to 3 include a methyl group, an ethyl group, an n-propyl group and an isopropyl group, and R ⁷
The divalent organic group having 1 to 6 carbon atoms represented by
For example, ethylene group, 1,3-propylene group, 1,4-butylene group, 1,6-hexylene group, etc.
The alkylene group of 6 and the like can be mentioned.

As the alkyl group having 1 to 6 carbon atoms represented by R ² and R ³ in the above formula (I),
For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a neopentyl group, an n-hexyl group, and the like, and a hydrolyzable group represented by Y is Easily hydrolyzed,
An organic group that forms a silanol group together with a Si atom is included, and specifically, methoxy, ethoxy, propoxy,
Examples thereof include an alkoxyl group having 1 to 6 carbon atoms such as butoxy and hexoxy groups; and an alkoxyalkoxyl group having 2 to 6 carbon atoms such as methoxyethoxy, ethoxyethoxy, methoxypropoxy and ethoxybutoxy groups.

The halogen atom represented by X in the above formula (II) includes chlorine, iodine and bromine atoms, and the organic acid carboxylate represented by X includes formic acid, acetic acid, propionic acid, butyric acid, 1 to 6 carbon atoms such as acrylic acid and methacrylic acid
The residue (organic acid carboxylate) obtained by removing the hydrogen atom of the carboxyl group from the organic acid can be mentioned.

Specific examples of the onium group-containing silane compound as the component (C) include, for example, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, N-β- (N-vinylbenzyl). Aminoethyl) -γ-aminopropyltrimethoxysilane · hydrochloride, p-vinylbenzyl [3- (trimethoxysilyl) propyl] ammonium chloride and the like can be mentioned. In the present invention, the blending ratio of the water-dispersible silica fine particles (A) and the water-soluble or water-dispersible organic resin (B) in the inorganic-organic composite resin is (A) / (B). Generally 10/90 to 95/5, preferably 50/50 by weight solids ratio of
It is possible to set it in the range of 20 to 80. If the content of the water-dispersible silica fine particles (A) is less than 10% with respect to the sum of both components (A) and (B), the hydrophilization effect is insufficient, while if it exceeds 95%, a film is formed. There is a tendency for sex to decline. The amount of the onium group-containing hydrolyzable silane compound (C) is generally 0.5 to 20 parts by weight based on 100 parts by weight of the sum (solid content) of both components (A) and (B),
In particular, the range of 3 to 10 parts by weight is preferable.

When the amount of the onium group-containing hydrolyzable silane compound (C) is less than 0.5 parts by weight, the hydrophilicity sustainability is insufficient, and when it exceeds 20 parts by weight, the hydrophilicity sustaining effect is further enhanced. Not only can it not be increased, but the water resistance of the coating tends to deteriorate.

The inorganic-organic composite resin of the present invention is, for example, a water-dispersible silica fine particle (A) and an organic resin (B).
Of the onium group-containing hydrolyzable silane compound (C) are mixed at room temperature, preferably 1
It can be produced by aging at a temperature of 0 ° C. or higher, but usually the mixture is continuously heated at a temperature of 50 ° C. or higher and a boiling point or lower, preferably about 50 to about 90 ° C. Is preferable, and the bonding between the components is sufficiently performed by heating. As the heating continues, the viscosity of the mixed solution gradually increases, and finally becomes almost constant and no change is observed. Therefore, the heating may be stopped at that time. It usually takes 0.5 to 5 hours. The components (A), (B) and (C) are preferably mixed by gradually adding and stirring the component (C) into a liquid in which the components (A) and (B) are uniformly mixed.

The hydrophilic treatment composition of the present invention contains an inorganic-organic composite resin produced as described above as a main component, and usually contains water in addition to the resin, and If necessary, it may contain an organic solvent, a neutralizing agent, a coloring pigment, a rust preventive pigment, a rust preventive, a curing agent, a fungicide, a surfactant and the like.

Examples of color pigments that can be blended are cyanine green, cyanine blue, carbon black,
Examples thereof include quinacridone red, and examples of anticorrosion pigments include chromate-based pigments such as zinc chromate and strontium chromate; lead-based anticorrosion pigments such as lead silicate and lead hydroxide. Examples of the rust agent include phenolcarboxylic acids such as tannic acid and gallic acid and salts thereof; organic phosphoric acids such as phytic acid and phosphinic acid and heavy phosphoric acid and metal salts thereof; nitrite salts such as sodium nitrite. You can Further, as a curing agent that can be used, for example, titanium, zirconium, molybdenum, a cationic compound of a metal such as vanadium and a chelate compound of these metals, a melamine resin that is usually used as a curing agent for coating materials, a urea resin, Examples thereof include polyisocyanate resin.

The hydrophilic treatment composition containing the inorganic-organic composite resin as a main component obtained as described above is applied to the surface of an object to be coated such as metal by a method known per se, and dried at room temperature or heat-cured. In some cases, a cured coating film having excellent hydrophilicity can be formed on the surface of the article to be coated by curing it by irradiation with ultraviolet rays.

Examples of the article to be coated include metals such as aluminum, aluminum alloys, copper, brass, galvanized steel sheets and iron; wood and the like. In particular, aluminum and aluminum alloys are used as fin materials for heat exchangers of air conditioners.
Usually, it is applied and cured so that the cured coating film has a thickness of 0.1 to 5 μm. As a coating method, when coating aluminum or aluminum alloy before being processed into fin material, spray coating, roll coating, flow coating-ironing coating, etc. are usually used, and after curing the coating film. Processed into fin material. In addition, when aluminum or aluminum alloy is processed into fin material and is applied to the heat exchanger before coating, usually dip coating,
A coating method such as spray coating is used, and then the coating film is cured. The curing conditions of the coating film can be appropriately set depending on the type of the hydrophilic treatment composition used, the line conditions, and the like. Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

However, these examples are merely examples and are not intended to limit the present invention in any way.
In the following description, "part" and "%" are "parts by weight"
And "% by weight" are shown.

[0033]

【Example】

Example 1 315 parts of water was charged into a 2-liter four-necked flask, and
While stirring at 5 ° C, the degree of saponification of flakes is 98.0.
60 parts of 99.4 polyvinyl alcohol [Poval PVA-117 manufactured by Kuraray Co., Ltd.] was dissolved. After cooling this to room temperature, 200 parts of colloidal silica aqueous dispersion having a solid content of 20% [“Snowtex C” manufactured by Nissan Kagaku Co., Ltd.] was added with stirring.

After completion of the addition, 5 parts of octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride as an onium group-containing hydrolyzable silane compound was added dropwise. After that, the mixture was heated to 80 ° C. and kept at the same temperature for 3 hours and 30 minutes to react, then cooled to room temperature and stirred to produce UFR65 [Mitsui Cyanamid Co., Ltd.].
Manufactured, urea resin, solid content 100%] was added dropwise to obtain a hydrophilic treatment composition containing an inorganic-organic composite resin as a main component.

Examples 2 to 10 and Comparative Examples 1 to 5 Treatment was carried out in the same manner as in Example 1 except that the types and amounts of the organic resin, silica fine particles, silane compound and curing agent were as shown in Table 1 below. Each hydrophilic treatment composition was obtained. The indication of the amount in Table 1 is based on the solid content.

Preparation of test coated plate An aluminum plate (A1050, plate thickness 0.1 mm) was degreased with an alkaline degreasing agent [Nippon CB Chemicals Co., Ltd., trade name "Chemic Cleaner 561B"], and then a chromate treatment agent [Japan Parkerizing Chromate treatment (coating amount in terms of chromium: 30 mg / m ² ) was performed with a product name “Alchrome 712” manufactured by Co., Ltd. to obtain a coated object. Each of the compositions of Examples and Comparative Examples was applied to the above-mentioned objects to be dried so as to have a dry film thickness of 1 micron, and baked with hot air at 220 ° C. for 30 seconds to form a hydrophilization-treated film. Got

After press oil was applied to the test coated plate and degreasing treatment was performed with trichlene vapor for 5 minutes, the appearance, hydrophilicity and corrosion resistance of the coating film were tested. The test results are shown in Table 1 below.

The tests in Table 1 were conducted according to the following test methods.

Appearance of coating film: The degreased coated plate was visually evaluated. The case where no abnormalities were found in the coating film was marked with ◯.

Hydrophilicity: An initial coated plate that has been degreased, and this initial coated plate is tap water running water (flow rate is 1 m ² of coated plate).
15 kg / hr) for 200 hours, and then the coated plate that has been pulled up and the initial coated plate are soaked in running tap water for 7 hours, then pulled up and dried in the room for 17 hours. The water wettability and the contact angle of water droplets of each cycled coated plate were measured by the following methods.

Water wettability: The coated plate is immersed in a beaker containing tap water for 10 seconds, and the wetted state of the coated plate surface when pulled up is visually determined.

O: The entire surface is wet with water, and there is no unevenness of water even after 10 seconds of pulling.

Δ: The entire surface is wet immediately after pulling up, but after 10 seconds of pulling up, water is in the center from the edge of the coated plate.

X: A state where polka dots are formed immediately after pulling up and the entire coated plate is not wet with water.

Contact angle: The contact angle between the coated plate and water is measured by
The coated plate is dried at 80 ° C. for 5 minutes and then measured with a contact tangle meter DCAA type manufactured by Kyowa Chemical Co., Ltd. Corrosion resistance: According to JIS-Z-2371 salt spray test method. The test time was 500 hours.

The case where neither white rust nor blistering occurred was rated as good (◯).

The case where a small amount of white rust or blister was generated was regarded as a little defective (Δ).

[0048]

[Table 1]

The types of organic resin, silica fine particles, silane compound and urea resin in Table 1 are as follows.

Organic resin A: Polyvinyl alcohol (saponification degree: 98.0-99.4) Organic resin B: Carboxymethyl cellulose (etherification degree: 0.7-0.8) Organic resin C: Water dispersion Acetic Acid Neutralization Cationic Acrylic Resin Silica Fine Particles D: Snowtex C [Nissan Chemical Co., Ltd.
Aqueous dispersion of colloidal silica] Silica fine particles E: Aerosil 200 [manufactured by Nippon Aerosil Co., Ltd., powdered fumed silica] Silane compound F: Octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride Silane compound G: N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane / hydrochloride Silane compound H: γ- (methacryloxypropyl) trimethoxysilane Silane compound I: N-β- (aminoethyl) γ -Aminopropyltrimethoxysilane Hardening agent J: UFR65 [Mitsui Cyanamid Co., Ltd., urea resin] Hardening agent K: Dihydroxy bis (lactato) titanium

[0051]

EFFECT OF THE INVENTION By using the composition of the present invention, a coating film having excellent hydrophilicity can be formed, and heat treatment can be performed by the method for hydrophilizing an aluminum (alloy) fin material using this composition. It is possible to provide a hydrophilized fin that is suitable as a paint fin material for an exchanger, has excellent hydrophilic durability, has good corrosion resistance, and has no odor problem in the early stage of cooling operation.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09D 7/12 PSL 7211-4J F28F 3/00 9141-3L

Claims (3)

[Claims] 1. (A) Water-dispersible silica fine particles,
(B) a water-soluble or water-dispersible organic resin and (C) an onium group-containing hydrolyzable silane compound, and the solid content weight ratio of the component (A) to the component (B) is 10: 9.
0 to 95: 5, and (C) with respect to 100 parts by weight of the total solid content of the components (A) and (B).
A hydrophilic treatment composition comprising an inorganic-organic composite resin as a main component, the amount of which is in the range of 0.5 to 20 parts by weight. 2. A silane compound (C) is represented by the following general formula (I): [In the formula, R ¹ represents an onium-containing group, and R ² and R ³
Are the same or different and each represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, Y represents a hydrolyzable group, X represents a halogen atom or an organic acid carboxylate, and a and b each represent 0 or The composition according to claim 1, which is a compound represented by the formula 1. 3. A fin material made of aluminum or an aluminum alloy is coated with the composition according to claim 1 or 2 and cured to form a coating film having a cured coating film thickness of 0.1 to 5 μm. A method for hydrophilizing a fin material, comprising: