JP2000281936A - Aluminum or aluminumalloy hydrophilicity treatment composition and method for hydrophilicity treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide aluminum or aluminum alloy hydrophilicity treatment compositions having continuous corrosion resistance and hydrophilicity and capable of forming coated films which do not cause odor development, and a method for the hydrophilicity treatment. SOLUTION: Compositions for the hydrophilicity treatment of aluminum or its alloys comprise (P1) a water soluble polymer having a monomer (I) represented by the formula (wherein R1 is hydrogen or methyl; and R2 and R3 are the same or different and each is hydrogen, 1-4C alkyl, benzyl or 2C or 3C hydroxyalkyl) as the constituting unit which can be obtained by the polymerization or copolymerization of monomer (I), (A) a water soluble trivalent chromium compound, (B) a water soluble zirconium compound or titanium compound and, if necessary or desired, further (C) water at such a ratio of components (PI), (A) and (B) that based on 100 pts.wt. solids content of component (PI), component (A) is 0.01-70 pts.wt. and component (B) is 0.001-70 pts.wt. A method for the hydrophilicity treatment uses these compositions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for hydrophilizing aluminum or an aluminum alloy and a method for hydrophilizing the composition using the composition. More specifically, the present invention relates to aluminum or its alloys, more particularly, aluminum or its alloy materials, aluminum or its alloy products, such as heat exchangers made of aluminum or its alloys, etc. The present invention relates to a composition for hydrophilizing treatment for imparting properties and corrosion resistance, and a method for hydrophilizing aluminum or an alloy thereof using the same.

[0002]

2. Description of the Related Art Conventionally, most heat exchangers made of aluminum or its alloys are designed so that the areas of the heat radiating portion and the cooling portion are made as large as possible in order to improve the heat radiating or cooling effect. The spacing is very narrow. Also, cuts called louvers are formed between the fins to minimize the ventilation resistance. For this reason, when used for cooling, moisture in the air aggregates on the heat exchanger surface, especially between the fins, and the aggregated water tends to become water droplets as the fin surface becomes more hydrophobic,
In many cases, clogging occurs in the fin gap to increase ventilation resistance and reduce the heat exchange rate. Further, the water droplets accumulated in the fin gaps are easily scattered by the blower of the heat exchanger, so that the water droplets cannot be received by the tray installed below the heat exchanger, and the area near the heat exchanger is often contaminated with water.

[0003] Therefore, in order to prevent water droplets from remaining in the fin gaps and causing clogging by the water droplets, some treatments have been proposed and implemented for imparting hydrophilicity to the aluminum or its alloy surface and improving water wettability. ing. Conventionally, hydrophilizing agents applied to the fin surface of a heat exchanger made of aluminum or its alloys are roughly classified into inorganic compounds, particularly those obtained by adding or adding organic polymers to alkali silicates, and organic polymers alone. It is divided into two types. The former has superior hydrophilicity and hydrophilic sustainability as compared to the latter, and is therefore widely used in the market at present. However, in recent years, the problem of off-flavors generated from heat exchangers has been highlighted, and it is estimated that the cause is due to scattering of inorganic compounds.

A conventional heat exchanger made of aluminum or an alloy thereof for a car air conditioner is manufactured by cutting, punching, and welding a coil material of aluminum or an alloy thereof and then assembling the heat exchanger made of aluminum or an alloy thereof. After pre-cleaning, a chemical conversion treatment such as a chromate chromate treatment is performed to impart corrosion resistance, and then a hydrophilic treatment as described above is performed. The reason why the chemical conversion treatment for imparting corrosion resistance is performed prior to the hydrophilization treatment is that corrosion resistance cannot be imparted to the heat exchanger made of aluminum or its alloy only by the above-mentioned hydrophilic treatment. However, separately performing the corrosion resistance and the hydrophilization treatment is troublesome, and furthermore, after the chemical conversion treatment, a water removal step such as a water washing step or an air blow is generally required. It becomes large and complicated. In addition, chromate chromate and phosphate chromate, which are generally used in chemical conversion treatment, use hexavalent chromium which is harmful to the human body in the treating agent, and thus may adversely affect the environment and wastewater treatment.

Various methods have been proposed to solve these problems. For example, JP-A-63-318496
In order to omit the chemical conversion treatment, the publication discloses a "surface treatment method for a heat exchanger characterized by having a hydrophilicity, an anticorrosive property, an antibacterial property and an antifungal property by one surface treatment step". I have. However, the constituent components are not clearly described in the claims as well as in the examples, and the specificity is poor. JP-A-63-171684 discloses a "method for treating an aqueous hydrophilic treatment agent having corrosion resistance".
This is to form a film that imparts corrosion resistance and hydrophilicity to a resin synthesized from a specific monomer on aluminum or its alloy material. However, this method is not yet sufficiently hydrophilic, and is generally used as a base for a hydrophilic film. Further, JP-A 1-2
Japanese Patent No. 70977 discloses a "method of hydrophilizing aluminum or an alloy thereof having good hydrophilicity and corrosion resistance." This is to form a film imparting corrosion resistance and hydrophilicity by using a specific polymer P1, a polymer P2 having a specific functional group, and a crosslinking agent. However, this method is not environmentally friendly because hexavalent chromium is contained in the hydrophilic film.

Therefore, by applying directly to the surface of an aluminum or alloy product thereof, such as a heat exchanger made of aluminum or an alloy thereof, a uniform film is formed, the hydrophilicity is maintained for a long time, and the undercoat film is formed. A composition for hydrophilizing treatment that does not contain hexavalent chromium and has good corrosion resistance even if not provided has not yet been developed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
By applying directly to the surface of aluminum or its alloy products such as aluminum or its alloy materials or heat exchangers made of aluminum or its alloys, excellent corrosion resistance can be maintained for a long time without using a commonly used undercoat. It is an object of the present invention to provide a composition for hydrophilization treatment capable of forming a film that does not produce odor and can maintain excellent hydrophilicity over a long period of time, and a hydrophilization treatment method using the same. I do.

[0008]

Means for Solving the Problems As a result of intensive studies on the means for solving the above problems, the present inventors have found that a polymer having a specific structure, a water-soluble trivalent chromium compound, It has been found that these problems can be solved by applying a hydrophilic treatment composition containing a water-soluble zirconium compound or a water-soluble titanium compound, and the present invention has been completed.

That is, the present invention provides a compound represented by the general formula

[0010]

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Wherein R ¹ is a hydrogen atom or a methyl group, and R ² and R ³ are the same or different and each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzyl group or a carbon atom having 2 carbon atoms. Or represents a hydroxyalkyl group of 3), obtained by homopolymerization of the monomer (I) or copolymerization of two or more types of the monomer (I), or copolymerization of the monomer (I) with the monomer (I) Or a homopolymer or a homopolymer obtained by copolymerizing the monomer (I) or a salt thereof with the monomer (I) or the salt thereof under the condition that the ratio of the monomer (I) in the total monomer is 40 mol% or more. A water-soluble polymer (P1), a water-soluble trivalent chromium compound (A), a water-soluble zirconium compound or a titanium compound (B) obtained by subjecting the copolymer to conventional modification, and Contain additional water according to,
The mutual proportions of P1, A and B are such that A0.01 to 70 parts by weight and B0.00
The present invention relates to a composition for hydrophilizing aluminum or an aluminum alloy in an amount of 1 to 70 parts by weight.

In the above composition for hydrophilizing aluminum or its alloy, a carboxyl group, a sulfonic acid group, a phosphonic acid group, a primary amino group, a secondary amino group,
A monomer (III) having a tertiary amino group, a quaternary ammonium group, a hydroxyl group, a glycidyl group or an amide group, different from the monomer (I), and homopolymerization of any of these salts or monomer (III); Nonionic monomers and monomers obtained by copolymerization of two or more of these salts or copolymerizable with monomer (III) or a salt thereof, but having no hydroxyl group, glycidyl group or amide group (I
II) or a water-soluble polymer (P2) obtained by copolymerization with a salt thereof, wherein the ratio of the monomer (III) or a salt thereof in the total monomer is 40 mol% or more, is 100 parts by weight of P1 based on the solid content. When the content is 1 to 400 parts by weight, the hydrophilicity of aluminum or an alloy thereof can be further improved.

Further, when the above-mentioned composition for hydrophilizing aluminum or its alloy contains a bactericidal agent having a decomposition temperature of 100 ° C. or higher, the putrefaction odor due to metabolites of microorganisms that propagate in the fin gap is suppressed. Can be.

The present invention also provides a composition for hydrophilizing aluminum or an aluminum alloy as described above, which is applied to the surface of aluminum or an aluminum alloy, dried, and dried.
The present invention relates to a method for hydrophilizing aluminum or an aluminum alloy, which comprises forming a hydrophilic film having a thickness of about 20 μm.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, the “monomer” refers to a monomer having an ethylenic double bond and capable of being polymerized or copolymerized with the monomer. Further, the `` water-soluble polymer '' referred to in the present invention shall include both the water-soluble polymer itself as a solid content and the water-soluble polymer as an aqueous solution according to the custom in the art, and when both are separately discussed, Shall be given the term “solids” or “aqueous solution”. As is clear from the above, the water-soluble polymer referred to in the present invention may be a water-soluble polymer aqueous solution itself obtained by homopolymerizing or copolymerizing each component and further modifying as necessary, and is simply separated therefrom. Alternatively, it may be a purified and isolated water-soluble polymer solid. That is,
In the composition of the present invention, even if the polymerization initiator used in the production of the water-soluble polymer and other additives usually used in the polymerization and modification are contained, unless the object of the present invention is thereby prevented, No problem.

First, the composition for hydrophilizing aluminum or aluminum alloy will be described. Examples of the water-soluble polymer represented by P1 include a water-soluble polymer (P1-1) obtained by homopolymerization of the monomer (I) or copolymerization of two or more monomers (I). In the case of a copolymer, the mutual ratio is not limited. As the monomer (I), acrylamide, methacrylamide,
N-methylacrylamide, N, N-dimethylacrylamide and the like can be mentioned. In addition, for convenience of the following description, acrylamide, methacrylamide, N-methylacrylamide and N, N-dimethylacrylamide are individually or entirely referred to as a monomer (I ′).

The water-soluble polymer represented by P1 also includes a monomer (I) other than the monomer (I) copolymerizable with the monomer (I) or a salt thereof and the monomer (I). Copolymerization under the condition that the ratio of is at least 40 mol%. And the water-soluble polymer (P1-2) obtained by the above. Here, the monomer (I) to be copolymerized with the monomer (II) is not particularly limited as long as it is the monomer (I), but is preferably the monomer (I ′). The monomers (I) may be used alone or in combination of two or more.

Examples of the monomer (II) include a nonionic monomer (II-1), a cationic monomer (II-2) and an anionic monomer (II-3) different from the monomer (I). The monomers (II) may be used alone or in combination of two or more.

As the nonionic monomer (II-1), for example, 2-hydroxyalkyl (C = 2,3)
(Meth) acrylate, diacetone acrylamide, N
-Methylol acrylamide, acryloyl morpholine, acrylonitrile, alkyl (C = 1 to 6) (meth) acrylate, styrene, vinyl acetate and the like.

The cationic monomer (II-2) includes, for example, those represented by the following general formula:

[0021]

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Here, R ¹ represents a hydrogen atom or a methyl group, and M ¹ represents a group imparting cationicity, and examples thereof include the following.

[0023]

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(Wherein R ^a and R ^b are the same or different and each represents a hydrogen atom, an alkyl group (C = 1 to
6, especially 1, 2), a hydroxyalkyl group (alkyl represents C = 1 to 6, especially 1, 2), a phenyl group or a benzyl group, and y represents an integer of 1 to 3.

The salts of the cationic monomer (II-2) include salts with inorganic acids such as hydrochloric acid and sulfuric acid, salts with organic acids such as acetic acid and citric acid, and alkyl halides (methyl chloride, ethyl chloride). Adducts such as alkyl sulfate (methyl sulfate, ethyl sulfate, etc.), dimethyl diallylammonium salt (chloride, sulfate, etc.), and quaternary amines by reaction of chloromethylstyrene with tertiary amines (triethylamine, etc.). Secondary ammonium salts and the like.

Examples of the anionic monomer (II-3) include those represented by the following general formula, and other unsaturated carboxylic acids such as maleic anhydride and itaconic acid:

[0027]

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Here, R ¹ represents a hydrogen atom or a methyl group, and M ² represents a group imparting anionicity, and examples thereof include the following.

[0029]

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The salt of the anionic monomer (II-3) includes sodium salt, potassium salt, ammonium salt,
And salts with amines such as triethylamine.

The composition of the water-soluble polymer (P1-2) can thus be represented as follows: General formula _{(I) n - (II-} 1) p ( where, n ≧ 40, p = 1~60 , n + p = 100) Noni Oh nick polymer represented by the general formula _{(I) n - (II-} 1 ) _P- (II-2 or a salt thereof)
_q (where n ≧ 40, p = 0 to 59, q = 1 to 60, n +
p + q = 100), a cationic polymer represented by the general formula (I) _n- (II-1) _p- (II-3 or a salt thereof)
_r (where n ≧ 40, p = 0 to 59, r = 1 to 60, n +
p + r = 100), or an anionic polymer represented by the general formula (I) _n- (II-1) _p- (II-2 or a salt thereof)
_q- (II-3 or a salt thereof) _r (where n ≧ 40, 0 ≦ p <30, q = 1 to 59, r =
1 to 59, n + p + q + r = 100).

The water-soluble polymer represented by P1 is also obtained by subjecting the above-obtained homopolymer or copolymer, that is, the water-soluble polymer (P1-1) or (P1-2) to conventional modification. Water-soluble polymer (P1-3)
Is mentioned. Examples of conventional modifications include: 1) conversion of an amide group to a carboxyl group by hydrolysis, 2) conversion of the amide group to an amino group by Hoffman rearrangement, 3) conversion of the amide group to HN (R ⁴ ) (R ⁵ ) And -CONH-C by Mannich reaction using formaldehyde
Conversion to H ₂ —N (R ⁴ ) (R ⁵ ) where R ⁴ and R ⁵
Are the same or different and each have 1 to 4 carbon atoms
Represents an alkyl group, a hydroxyalkyl group having 2 or 3 carbon atoms or a benzyl group), 4) a side chain ester group and an alkylenediamine (H ₂ N—R ⁶
-NH ₂₎ introducing -CONH-R ⁶ -NH ₂ by reaction with (wherein, R ⁶ is obtained by reaction of representative) 5) 2) to 4) an alkylene group having 2 to 6 carbon atoms (substituted ) Quaternary ammonium conversion by alkylation of an amino group, and the like.

The homopolymerization or copolymerization method for obtaining the water-soluble polymer (P1) of the present invention is not particularly limited, and can be carried out by a conventional method. For example, 1
A monomer or a mixture of two or more species is dissolved or suspended in water, and potassium persulfate or the like is used as a polymerization initiator and sodium thiosulfate or the like is used as a polymerization accelerator.
The polymerization is carried out at 0-100 ° C. For adjusting the degree of polymerization, a secondary alcohol, mercaptosuccinic acid or the like can be used as a chain transfer agent. Modification (hydrolysis, Hoffmann rearrangement, Mannich reaction, quaternary ammonium conversion, etc.) of the obtained homopolymer or copolymer as necessary can be carried out by a conventional method.

The molecular weight of the obtained water-soluble polymer (P1) should be 5,000 or more by gel permeation chromatography (GPC) using polyacrylic acid ester as a standard substance, to ensure the durability of the film. Therefore, it is appropriate. The molecular weight is preferably 5,000-
300,000, more preferably 10,000 to 10
It is 0000.

Next, the water-soluble trivalent chromium compound (A) is not particularly limited, and examples thereof include chromium sulfate, chromium nitrate, chromium fluoride, chromium acetate, chromium chloride, and chromium biphosphate. Water-soluble trivalent chromium compound (A)
Is generally required to be 0.01 to 70 parts by weight, preferably 0.1 to 50 parts by weight, based on 100 parts by weight of the solid content of the water-soluble polymer (P1). More preferably 1 to 50 parts by weight,
Even more preferably, it is 40 parts by weight. If the amount is less than 0.01 part by weight, the corrosion resistance is insufficient, and if it exceeds 70 parts by weight, odor may be generated.

The water-soluble zirconium compound or titanium compound (B) is not particularly restricted but includes, for example, zirconium acetate, zirconium nitrate, zirconium chloride,
Hexafluorozirconic acid and its salt (Na salt,
K salt), zirconium sulfate, zirconium carbonate, etc., hexafluorotitanic acid and salts thereof (Na salt, K salt, N salt)
H ₄ etc.), titanium sulfate and the like. The amount of the water-soluble zirconium compound or titanium compound (B) used is
Generally, it is necessary to be 0.001 to 70 parts by weight, preferably 0.1 to 50 parts by weight, preferably 0.5 to 0.5 parts by weight, based on 100 parts by weight of the solid content of the water-soluble polymer (P1).
The amount is more preferably from 50 to 50 parts by weight, and even more preferably from 1 to 40 parts by weight. 0.0%
If it is less than 01 parts by weight, the corrosion resistance is insufficient, and if it exceeds 70 parts by weight, odor may be generated.

As mentioned above, the composition of the present invention for hydrophilizing aluminum or an alloy thereof, if it comprises the above-mentioned components P1, A and B and, if necessary, further water, achieves the object of the present invention. However, as further components, carboxyl group, sulfonic acid group, phosphonic acid group, primary amino group, secondary amino group, tertiary amino group, quaternary ammonium group, hydroxyl group, glycidyl group Or a monomer (III) having an amide group, different from monomer (I), obtained by homopolymerization of any of these salts or copolymerization of monomer (III) and two or more of these salts, or Nonionic which can be copolymerized with (III) or a salt thereof, but has no hydroxyl group, glycidyl group or amide group Obtained by copolymerization of Nomar the monomer (III) or a salt thereof, the ratio of the monomer (III) or a salt thereof of the total monomers is 40 mol%
The above water-soluble polymer (P2) is
When it is contained in an amount of 1 to 400 parts by weight based on 100 parts by weight of P1, the hydrophilicity of the obtained film can be further improved.

The monomer (III) having a carboxyl group, a sulfonic acid group or a phosphonic acid group in the molecule
And as the salts thereof, the anionic monomers described in the description of P1 and their salts can be used. In the above, as the monomer (III) having a primary amino group, a secondary amino group, a tertiary amino group or a quaternary ammonium group in the molecule, and salts thereof,
The cationic monomers and salts thereof described in the description of P1 can be used. In the above, the molecule has a hydroxyl group, a glycidyl group or an amide group,
As the monomer (III) different from the monomer (I),
2-hydroxyalkyl (C = 2,3) (meth) acrylate, N-methylol (meth) acrylamide, diacetone acrylamide, or the like can be used.

The nonionic monomer which can be copolymerized with the monomer (III) but does not have any of a hydroxyl group, a glycidyl group and an amide group is not particularly limited. For example, styrene, alkyl (C = 1
To 8) (meth) acrylate, vinyl acetate and the like.

Water-soluble polymer (P2) used in the present invention
The method of the above-mentioned homopolymerization or copolymerization for obtaining the same may be the same as that of the water-soluble polymer (P1).

The molecular weight of the obtained water-soluble polymer (P2) is preferably 1,000 or more by gel permeation chromatography (GPC) using polyacrylic acid ester as a standard substance, in order to ensure the hydrophilicity of the film. Therefore, it is appropriate. The molecular weight is preferably from 1,000 to
500,000, more preferably 5,000-20
It is 0000.

When a water-soluble polymer (P2) is used,
The amount used in the composition of the present invention is P11
1 to 400 parts by weight with respect to 00 parts by weight,
~ 300 parts by weight are preferred.

Further, the composition for hydrophilization treatment of the present invention may further comprise:
By containing a disinfectant having a decomposition temperature of 100 ° C. or higher, putrefaction odor due to metabolites of microorganisms that propagate in the fin gap can be suppressed. The antibacterial agent having a decomposition temperature of 100 ° C. or higher is not particularly limited.
-Methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2- (4-thiocyanomethylthio) benzothiazole, 2,2-dibromo-
3-nitrilopropionamide, sodium ethylenebis (dithiocarbamate), sodium 2-pyridinethiol-1-oxide, 2,2'-dithiobis (pyridine-1-oxide), 2,4,5,6-tetrachloroiso Phthalonitrile, 2-methylcarbonylaminobenzimidazole, zinc 2-pyridinethiol-1-oxide, 2- (4-thiazolyl) -benzimidazole, p-chloro-m-xylenol, 1,2-benzisothiazolin-3-one , 2-bromo-2-nitropropane-1,3-diol, barium metaborate, 2-n
-Octyl-4-isothiazolin-3-one, bis (1
-Hydroxy-2-pyridinethionato) zinc, zeolite compounds having Ag or Cu, and the like. When the above antibacterial agent is used, the amount of the antibacterial agent used in the composition of the present invention may be any amount that can provide an antibacterial effect.
The appropriate amount is 0.01 to 50 parts by weight, preferably 0.1 to 50 parts by weight, based on 100 parts by weight of the solid content.

The composition for hydrophilizing aluminum or its alloy according to the present invention may further contain a rust inhibitor, a leveling agent, a filler, a coloring agent, a surfactant, an antifoaming agent, etc. It can be added within a range that does not impair the film performance.

The solid content concentration of the composition for hydrophilizing aluminum or its alloy of the present invention is determined by applying the composition once to the surface of aluminum or its alloy and drying it, 0.05-20 μm, especially 0.1-
What is necessary is just a solid content density | concentration which becomes 5 micrometers.

Next, using the above composition for hydrophilization treatment,
The method for hydrophilizing aluminum or aluminum alloy of the present invention will be described. The material to be hydrophilized is aluminum or an aluminum alloy, more specifically, a material or product made of aluminum or an aluminum alloy.
The aluminum alloy is not particularly limited, and examples thereof include an alloy of aluminum and manganese, silicon, magnesium, or the like, the aluminum alloy having an aluminum content of 80% by weight or more.
IS3004, JIS5052 and the like. Examples of such a material made of aluminum or aluminum alloy include a plate material, a tube material, a rod material, a fin material used for a heat exchanger, and examples of the product include a heat exchanger and a refrigerator. The composition for hydrophilization treatment of the present invention is particularly preferably used for hydrophilization treatment of a heat exchanger made of aluminum or aluminum alloy by post-coat treatment.

Prior to application of the composition of the present invention, the surface to be applied is generally degreased, washed with water and dried by a conventional method. The composition of the present invention is applied by a usual coating method, for example, dipping,
It can be applied to the surface of aluminum or aluminum alloy by spraying, roll coating, flow coating or the like. After applying the composition of the present invention, drying is performed. The drying method is not particularly limited, but usually, drying is performed by hot air drying.
It is suitable to carry out at a temperature of from 300 to 300C, especially from 100 to 250C.

The thickness of the film after drying needs to be 0.05 to 20 μm, preferably 0.1 to 5 μm. If it is less than 0.05 μm, it is difficult to impart sufficient hydrophilicity to the material to be hydrophilized, and if it exceeds 20 μm, the thermal conductivity of the material to be hydrophilized may be reduced.

[0049]

The film obtained by using the composition for hydrophilizing aluminum or aluminum alloy of the present invention does not generate odor and maintains excellent corrosion resistance and hydrophilicity for a long period of time. Further, by imparting corrosion resistance to the hydrophilic film as described above, it has become possible to omit the chemical conversion film which has been generally performed so far. The mechanism of the corrosion inhibiting effect of the hydrophilic film by the composition of the present invention is not necessarily clear, but is considered as follows. Water-soluble polymer (P
Although it is known that 1) and a water-soluble trivalent chromium compound form a film having a network structure, the water-soluble zirconium compound or titanium compound (B) is used to form a film having a stronger network structure. It is considered that the progress of corrosion is hindered. In addition,
It is considered that this hydrophilic film alone exhibits excellent corrosion resistance over a long period of time and can maintain excellent hydrophilicity and deodorization over a long period of time. It is considered that the odor is not generated for a long period of time because the formed film does not contain an odor component and the film prevents generation of an odor component due to corrosion or the like.

[0050]

The present invention will be described in more detail with reference to the following examples, which are merely illustrative and do not limit the present invention in any way. Example 1 A heat exchanger made of aluminum (JIS 3003) was heated to 60 ° C.
Alkaline degreasing agent (fine cleaner 31)
5, immersed in a 30 g / L aqueous solution of Nippon Parkerizing Co., Ltd. for 50 seconds to remove surface contaminants such as oil, and then washed with tap water for 30 seconds. This heat exchanger was added to a hydrophilizing treatment composition comprising 100 parts by weight of polyacrylamide solids (molecular weight: about 50,000), 10 parts by weight of chromium biphosphate, 10 parts by weight of hexafluorotitanic acid and 5000 parts by weight of water. After immersion at 30 ° C. for 30 seconds, the liquid was removed by air blowing, and then dried by heating in a hot air circulation oven adjusted to 140 ° C. for 30 minutes to form a hydrophilic film. The thickness of this film was measured using a surface carbon measuring device manufactured by LECO (USA).

Example 2 In place of the composition for hydrophilization treatment of Example 1, 100 parts by weight of polyacrylamide solids (molecular weight: about 50,000), 30 parts by weight of chromium biphosphate, and 30 parts by weight of hexafluorozirconic acid
A hydrophilic film was formed in the same manner as in Example 1, except that the composition for hydrophilization treatment consisting of parts by weight and 5000 parts by weight of water was used. Example 3 Instead of the composition for hydrophilization treatment of Example 1, 100 parts by weight of polyacrylamide solids (molecular weight: about 30,000), 10 parts by weight of chromium fluoride, 10 parts by weight of hexafluorozirconate, and 5000 parts by weight of water A hydrophilic film was formed in the same manner as in Example 1 except that the composition for hydrophilization treatment was used.

Example 4 The copolymer solid content of acrylamide (90 mol%) and 2-acrylamido-2-methylpropanesulfonic acid sodium salt (10 mol%) was used in place of the composition for hydrophilization treatment of Example 1. Molecular weight of about 40,000) 100 parts by weight, chromium fluoride 50 parts by weight, hexafluorozirconate 10
A hydrophilic film was formed in the same manner as in Example 1, except that the composition for hydrophilization treatment consisting of parts by weight and 5000 parts by weight of water was used. Example 5 In place of the composition for hydrophilization treatment of Example 1, 100 parts by weight of a sodium salt solid content (molecular weight: about 70,000) of a copolymer of acrylamide and acrylic acid in a ratio of 80:20 (molar ratio), sulfuric acid 10 parts by weight of chromium, 1 part by weight of titanium sulfate and 50 parts of water
A hydrophilic film was formed in the same manner as in Example 1 except that the hydrophilizing treatment composition consisting of 00 parts by weight was used. Example 6 Sodium poly-2-acrylamido-2-methylpropanesulfonate was added to the composition for hydrophilization treatment of Example 1 for 20 times.
A hydrophilic film was formed in the same manner as in Example 1, except that the composition for hydrophilization treatment added in parts by weight was used.

Comparative Example 1 The same as Example 1 except that the composition for hydrophilization treatment of Example 1 was replaced with the same composition for hydrophilization treatment except that polyacrylamide was not contained. To form a hydrophilic film. Comparative Example 2 The procedure of Example 1 was repeated, except that the composition for hydrophilization treatment of Example 1 was used instead of the composition for hydrophilization treatment of Example 1, except that chromium biphosphate was not used. Thus, a hydrophilic film was formed.

Comparative Example 3 Example 1 was repeated except that the composition for hydrophilization treatment was the same as that of Example 3 except that hexafluorozirconic acid was not used in place of the composition for hydrophilization treatment of Example 1. A hydrophilic film was formed in the same manner as described above. Comparative Example 4 Example 3 was repeated except that 200 parts by weight of hexafluorozirconic acid was used instead of 10 parts by weight of hexafluorozirconic acid in place of the composition for hydrophilizing treatment of Example 1.
A hydrophilic film was formed in the same manner as in Example 1 except that the same composition for hydrophilization treatment was used.

Evaluation Test The heat exchangers formed with the films, which were produced in Examples 1 to 5 and Comparative Examples 1 to 4, were evaluated by the following methods. <Test method> (1) Initial hydrophilicity The contact angle with water of the fin part of the heat exchanger was determined by FACE contact angle type CA.
-Measured using a P-type contact angle meter (manufactured by Kyowa Interface Science). (2) Hydrophilicity after durability The contact angle with water of the fin portion after immersion in running water at room temperature for 72 hours was measured using the contact angle meter.

(3) Corrosion Resistance In the corrosion resistance test based on the salt spray test method JIS Z-2371, the rust area after exposure for 72 hours was evaluated from the appearance. The evaluation criteria are as follows. ◎ No discoloration ○ Rust generation less than 10% □ Rust generation 10% or more and less than 25% △ Rust generation 25% or more and less than 50% × Rust generation 50% or more (4) Odor control Running water (deionized water: 0.5 L / min) The odor after 72 hours of immersion was evaluated on a 5-point scale. The evaluation criteria are as follows. ◎ Odorless ○ Smell slightly □ Smell a little △ Clearly smell × Strong smell

With respect to the aluminum heat exchanger having the hydrophilic coatings of the compositions of Examples 1 to 5 and Comparative Examples 1 to 4,
Table 1 summarizes the composition of the composition for hydrophilization treatment, the thickness of the film, and the results of evaluation by the above evaluation method. As is clear from Table 1, in the heat exchanger made of aluminum treated with the composition for hydrophilization treatment of the present invention of Examples 1 to 5, the film has excellent hydrophilicity, corrosion resistance and odor prevention even after the durability test. Having. In contrast, claims 1 of Comparative Examples 1 to 3
In an aluminum heat exchanger treated with the composition for hydrophilization treatment lacking even one of the components described in the above, the corrosion resistance of the film,
At least one of hydrophilicity and deodorant properties was insufficient. In Comparative Example 4, in which hexafluorozirconic acid was added in an excessive amount of 200 parts by weight, the deodorant properties were insufficient.

[0058]

[Table 1]

[0059]

The hydrophilic film obtained by treating aluminum or an aluminum alloy with the composition for hydrophilizing treatment of the present invention shows excellent hydrophilicity, corrosion resistance and deodorization as a single-layer film even after a durability test. .

Continuation of the front page (72) Inventor Masahiro Motozawa 1-15-1, Nihonbashi, Chuo-ku, Tokyo F-term (reference) in Japan Parkerizing Co., Ltd. 4D075 AB03 BB24Z BB33Z BB65X CA32 CA37 DA15 DB07 DC50 EA06 EB22 EC02 4J038 CG171 EA012 GA03 GA06 GA07 GA09 GA13 GA14 NA03 NA06 PC02

Claims (4)

[Claims] 1. A compound of the general formula (Wherein R ¹ is a hydrogen atom or a methyl group; R ² and R ³ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzyl group, or a C 2 or 3 Which is obtained by homopolymerization of the monomer (I) represented by a hydroxyalkyl group) or copolymerization of two or more types of the monomer (I), or copolymerizable with the monomer (I) and the monomer (I). Obtained by copolymerizing the monomer (II) or a salt thereof under the condition that the ratio of the monomer (I) in the total monomer is 40 mol% or more, or the homopolymer or copolymer obtained above To a water-soluble polymer (P1), a water-soluble trivalent chromium compound (A), a water-soluble zirconium compound or a titanium compound (B) obtained by conventional modification, and Consisting of water containing, P1, A and B
Is 100 parts by weight of the solid content of P1,
A composition for hydrophilizing aluminum or an aluminum alloy having 0.01 to 70 parts by weight and 0.001 to 70 parts by weight of B. 2. A carboxyl group, a sulfonic acid group, a phosphonic acid group, a primary amino group, a secondary amino group,
A monomer (III) having a tertiary amino group, a quaternary ammonium group, a hydroxyl group, a glycidyl group or an amide group, different from the monomer (I), and homopolymerization of any of these salts or monomer (III); Nonionic monomers and monomers obtained by copolymerization of two or more of these salts or copolymerizable with monomer (III) or a salt thereof, but having no hydroxyl group, glycidyl group or amide group
(III) or a copolymer thereof with a salt thereof,
A water-soluble polymer (P2) in which the ratio of the monomer (III) or its salt in the total monomer is 40 mol% or more
Is 1 to 4 parts by weight based on 100 parts by weight of P1 on a solid content basis.
2. The composition for hydrophilizing aluminum or an aluminum alloy according to claim 1, which contains 00 parts by weight. 3. The composition for hydrophilizing aluminum or an aluminum alloy according to claim 1, further comprising a bacteriostatic agent having a decomposition temperature of 100 ° C. or higher. 4. A composition for hydrophilizing aluminum or an aluminum alloy according to claim 1, which is applied to a surface of the aluminum or aluminum alloy,
A method for hydrophilizing aluminum or an aluminum alloy, comprising drying to form a hydrophilic film having a thickness of 0.05 to 20 μm.