JPH11300269A - Hydrophilic surface treating composition and hydrophilic surface treating membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the problems of foaming and mold abrasion during treatment work by preparing a hydrophilic surface treating composition to be applied to the surfaces of a metal and others from a substance containing a specified amount of a copolymer comprising poly(meth)acrylic acid or its salt and poly(styrene sulfonic acid) or its salt. SOLUTION: A hydrophilic surface treating composition is prepared by incorporating 1-90 wt.% based on solid content of a copolymer comprising poly(meth) acylilic acid or its salt and poly(styrene sulfonic acid) or its salt as an effective component, i.e., an acid-acid copolymer. The acid-acid copolymer is a copolymer which is obtained by copolymerizing acrylic acid and/or methacrylic acid with styrene sulfonic acid, and these can be salts neutralized with a base. For example, the salts of an alkali metal such as sodium and others are named as the kinds of the salts. In order to improve the durability of hydrophilicity, 1-90 wt.% in terms of the solid content, of a water-soluble polymer containing carboxyic groups can be incorporated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophilic surface treatment composition and a hydrophilic surface treatment film used for imparting hydrophilicity to the surface of various kinds of materials to be coated. For example, a metal surface such as a fin material for heat exchange made of aluminum or its alloy, or a plastic surface or a glass surface for the purpose of anti-fog treatment or antistatic treatment of various plastic products and glass products, etc. The present invention relates to a hydrophilic surface treatment composition for imparting properties and a hydrophilic surface treatment film.

[0002]

2. Description of the Related Art An air conditioner (air conditioner) having functions such as cooling, heating, and dehumidification is provided with a fin material for heat exchange in a heat exchange portion thereof. Excellent in heat resistance and heat conductivity,
It is formed of aluminum or its alloy.

When such an air conditioner is operated for cooling, the heat exchange portion on the indoor side becomes lower than the dew point of the moisture in the air, and the moisture in the air condenses on the fins used in the heat exchange portion. And adhere. The shape of the condensed water on the fin surface is determined by the wettability of the fin surface to water.On the fin surface with poor wettability, the condensed water becomes substantially hemispherical water droplets, and furthermore, water is formed between the fins. The bridge forms a bridge, which causes airflow resistance in the heat exchange portion, which impairs ventilation, causes noise, and in some cases, causes dew condensation to scatter and contaminate the surroundings.

Therefore, in order to solve such a problem,
Conventionally, the fin surface is subjected to a hydrophilic treatment. For example, a method using an inorganic hydrophilic treating agent containing water glass or the like as a main component (Japanese Patent Publication No. 2-42389, Japanese Patent Publication No. 3-77440). JP-A-1-299877, Japanese Patent Publication No. 3-475, and a method using an organic hydrophilic treating agent containing a resin having a hydrophilic group as a main component as a main component.
No. 70) and a method of using an organic hydrophilic treating agent having a surfactant added to impart resistance to volatile press oil (Japanese Patent Application Laid-Open No. 3-254864).

[0005] However, in the method using an inorganic hydrophilic treating agent, very good hydrophilicity is imparted to the fin surface, but the hydrophilic film formed on the fin surface mainly comprises silica (SiO ₂ ). It is a hard component and has the problem of severe wear of the mold at the time of press working.In addition, because it has the property of easily adsorbing odor components in the environment, there is also the problem that odor is felt at the beginning of cooling. is there.

In the method using the above-mentioned organic hydrophilic treating agent, there is no problem of mold abrasion or odor generation described above, but it is formed on the fin surface by volatile press oil used at the time of press working. The hydrophilic film is attacked,
There is another problem that the hydrophilicity is reduced.

Further, a method is proposed in which a surfactant is added to compensate for the drawbacks of the organic hydrophilic treating agent. However, when a surfactant is added, foaming occurs during the operation of the hydrophilic treatment and the hydrophilicity is increased. In addition to significantly reducing the workability of the water treatment, if dew water adheres to the fin surface during operation of an air conditioner, the surfactant starts to dissolve into the dew water from the hydrophilic film formed on the fin surface, and this dissolved surfactant However, there is also a serious problem that the drain pan deteriorates.

[0008]

Therefore, the present inventors have found that there is no foaming during the hydrophilic treatment operation, there is no problem of mold abrasion or odor generation, and further, the excellent hydrophilicity and the excellent As a result of intensive studies on a hydrophilic surface treatment composition and a hydrophilic surface treatment film capable of imparting durability, a copolymer comprising poly (meth) acrylic acid or a salt thereof and polystyrene sulfonic acid or a salt thereof was converted to a solid content. It has been found that a composition and a film containing 1 to 90% by weight in conversion achieve this object, and have completed the present invention.

Accordingly, it is an object of the present invention to provide a heat exchange fin material which is free from foaming during a hydrophilic treatment operation, has no problem of mold wear and odor generation, and has a surface to be coated, particularly aluminum or an alloy thereof. Hydrophilicity that can impart excellent hydrophilicity and its durability to plastic surfaces and glass surfaces for the purpose of anti-fog treatment and antistatic treatment of various metal products such as plastic products and glass products, etc. An object of the present invention is to provide a surface treatment composition and a hydrophilic surface treatment film.

[0010]

That is, the present invention relates to a copolymer comprising poly (meth) acrylic acid or a salt thereof and polystyrenesulfonic acid or a salt thereof (hereinafter simply referred to as "acid-acid copolymer") as an active ingredient. ") In the range of 1 to 90% by weight in terms of solid content, and a hydrophilic surface-treated film containing such a component as an active ingredient. Here, the solid content conversion refers to the solid content in the hydrophilic surface treatment composition remaining as a film when a hydrophilic surface treatment film is formed using the hydrophilic surface treatment composition as a whole (100% by weight). It means to convert.

The acid / acid copolymer used in the present invention is a copolymer obtained by copolymerizing acrylic acid and / or methacrylic acid with styrene sulfonic acid, and is obtained by copolymerizing acrylic acid, methacrylic acid and styrene sulfonic acid. May be a salt partially or wholly neutralized with a base. In the case of this salt, the neutralization may be performed before or after the polymerization. As the type of salt, for example, sodium salt,
Alkali metal salts such as potassium salts, ammonium salts,
Organic amine salts such as triethylamine salt and triethanolamine salt are exemplified.

Specific examples of the acid / acid copolymer include polyacrylic acid-polystyrene sulfonic acid copolymer, polymethacrylic acid-polystyrene sulfonic acid copolymer,
Polyacrylic acid-polystyrene sodium sulfonic acid copolymer, polymethacrylic acid-polystyrene sodium sulfonic acid copolymer, ammonium polyacrylate-polystyrene ammonium sulfonic acid copolymer, polyammonium methacrylate-polystyrene ammonium polysulfonic acid copolymer, Acrylic acid such as polyacrylic acid-polymethacrylic acid-polystyrene sulfonic acid copolymer or a salt thereof, methacrylic acid or a salt thereof, and styrene sulfonic acid or a salt thereof obtained by copolymerizing, further acrylic acid, Methacrylic acid, and those obtained by copolymerizing styrene sulfonic acid and then neutralized with a base, and the like, and these copolymers, in addition to only one of them, can be used alone, It can be used as a mixture of two or more That.

In this acid / acid copolymer, the molar ratio of the poly (meth) acrylic acid part to the polystyrene sulfonic acid part is 1:99 to 99: 1, preferably 10:90.
９０90: 10, and the weight average molecular weight is 800 or more, preferably 1000-1.
The range is preferably one million. If the molar ratio or the molecular weight is out of the above range, the hydrophilicity is reduced, the viscosity and the cost are increased, and thus, there are cases where it is not practical.

In the hydrophilic surface-treated composition and hydrophilic surface-treated film of the present invention, the content of the acid / acid copolymer varies depending on the kind and molecular weight, but is 1 to 90% by weight in terms of solid content. , Preferably in the range of 2 to 85% by weight. If the content is less than 1% by weight, the desired hydrophilicity cannot be exhibited, and if it exceeds 90% by weight, the film-forming properties are undesirably deteriorated.

In the present invention, for the purpose of improving the hydrophilicity persistence, a carboxyl group-containing water-soluble polymer other than the above-mentioned acid / acid copolymer is used in an amount of 1 to 90% by weight, preferably 10 to 90% by weight in terms of solid content. It can be blended in the range of 70% by weight. The carboxyl group-containing water-soluble polymer is obtained by homopolymerizing or copolymerizing one or more carboxyl group-containing monomers selected from acrylic acid, methacrylic acid, maleic acid, and itaconic acid. Homopolymer or copolymer and their salts, or one or two of these
A copolymer obtained by copolymerizing at least one kind of carboxyl group-containing monomer and another copolymerizable monomer and a salt thereof,
Cellulose derivatives such as carboxymethyl cellulose,
Further, alginates and derivatives thereof are used. Further, if the blending ratio is less than 1% by weight, the effect of blending such a carboxyl group-containing water-soluble polymer will not be exhibited, and if it exceeds 90% by weight, hydrophilicity will decrease. Problems arise.

Specific examples of such a carboxyl group-containing water-soluble polymer include polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, polyacrylic acid-polymethacrylic acid copolymer, and polyacrylic acid. Polyvinyl alcohol copolymer, polyacrylic acid-polyitaconic acid copolymer, polyacrylic acid-polymaleic acid copolymer, polymethacrylic acid-polyitaconic acid copolymer, polymethacrylic acid-polymaleic acid copolymer, polyacrylic acid- Polymethacrylic acid-polyacrylic ester copolymers and salts thereof, carboxymethylcellulose, alginate and the like can be mentioned. One of these carboxyl group-containing water-soluble polymers can be used alone, or a mixture of two or more thereof can be used.

In the hydrophilic surface treatment composition of the present invention,
The aqueous medium used may be water itself, and, for the purpose of improving coating properties and preventing foaming when using a surfactant, preventing uneven coating, etc., as required, such as ethanol, isopropanol and isobutanol. Alcohols and polyhydric alcohols such as ethylene glycol and glycerin may be added. The solid content concentration in the hydrophilic surface treatment composition when actually applied to a material to be coated is usually 1 to 30% by weight, preferably 2 to 20% by weight. If the solid content concentration is lower than 1% by weight, a sufficient film thickness cannot be ensured, while if it exceeds 30% by weight, there is a problem that the viscosity increases and coating becomes difficult.

Further, in the hydrophilic surface treatment composition and hydrophilic surface treatment film of the present invention, in addition to the above components,
A crosslinking agent is added for the purpose of improving the hydrophilicity persistence, or a water-soluble polymer other than the above-mentioned carboxyl group-containing water-soluble polymer is added for the purpose of further improving the effect of the initial hydrophilicity and the hydrophilicity persistence. Or, add a surfactant etc. to obtain better coatability and better hydrophilicity to press oil, and further add an antibacterial agent to the extent that hydrophilicity is not impaired for the purpose of imparting antibacterial properties Is also good.

Specific examples of the crosslinking agent include, for example, a zirconium compound, polyethyleneimine, and a water-soluble epoxy resin. The amount of the crosslinking agent is in the range of 0.1 to 90% by weight in terms of solid content. Is good.

Other water-soluble polymers other than the carboxyl group-containing water-soluble polymer include, for example, hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl Examples include cellulose derivatives such as methylcellulose (HEMC) and hydroxypropylmethylcellulose (HPMC); polyalkylene glycols such as polyethylene glycol, polyethylene oxide and polypropylene glycol and derivatives thereof; and polyvinyl alcohol and derivatives thereof. The amount of the other water-soluble polymer to be added is preferably in the range of 0.1 to 90% by weight in terms of solid content.

Further, as the surfactant, an anionic surfactant,
Cationic, nonionic, and amphoteric types can be used.As the anionic type, sodium dialkyl sulfosuccinate, sodium dodecylbenzenesulfonate, etc., and as the cationic type, octadecylamine acetate, etc. Preferred examples of the nonionic type include polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether, and examples of the amphoteric type include dimethylalkyl betaine. The amount of the surfactant added is preferably in the range of 0.1 to 50% by weight in terms of solid content.

Examples of the antibacterial agent include benzimidazole compounds, nitrogen-containing sulfur compounds, quaternary ammonium salts, chitosan, and degradation products obtained by treating chitosan with chitinase. The addition amount of this antibacterial agent is preferably in the range of 0.1 to 30% by weight in terms of solid content.

Furthermore, aqueous ammonia may be added to the hydrophilic surface treatment composition of the present invention for the purpose of improving the stability of the coating bath. The amount of the aqueous ammonia is preferably in the range of 0.1 to 10% by weight in terms of ammonia in the coating solution.

Here, the method of forming a hydrophilic film on the surface of the material to be coated using the hydrophilic surface treatment composition of the present invention is not particularly limited, but, for example, a fin material for heat exchange will be described as an example. Then, it is as follows.

First, the surface (front and back) of an aluminum material having a thickness of, for example, 100 to 110 μm is degreased and dried, and then a corrosion-resistant film is formed on the surface. The corrosion-resistant coating at this time is not particularly limited, and for example, an inorganic corrosion-resistant coating or an organic corrosion-resistant coating is formed by a chemical conversion treatment or a coating-type chromate treatment.

Next, the hydrophilic surface treatment composition is applied on the corrosion-resistant coating by an appropriate application means, for example, a roll coating method, a bar coating method, a spraying method, a dipping method or the like.
Preferably, the heating temperature is 150 to 300 ° C. and the heating time is 10 to 10.
Heat drying under the condition of 60 seconds to form a hydrophilic surface-treated film.

The fin material for heat exchange obtained in this manner is subjected to a forming process such as slitting or corrugating by applying a volatile press oil, and is used as a target fin material for heat exchange.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below based on examples and comparative examples.

Examples 1 to 12 and Comparative Examples 1 to 3 [Preparation of hydrophilic surface treatment composition] As a polymethacrylic acid-polystyrene sodium sulfonic acid copolymer (MSSNa), an average molecular weight of 3000 and a polymethacrylic acid portion (MA
A) 50/50 molar ratio (MAA / SSNa) of polystyrene sodium sulfonate portion (SSNa) (MSSNa: manufactured by Tosoh Corporation, solid content 20% by weight), average molecular weight 500
00 and a molar ratio (MAA / SSNa) of 50/50 (MSSNa
: Manufactured by Tosoh Corporation, solid content: 20% by weight), having an average molecular weight of 50,000 and a molar ratio (MAA / SSNa) of 20/80 (MSSNa: manufactured by Tosoh Corporation, solid content: 20% by weight), average molecular weight of 40,000 Molar ratio (MAA / SSNa) 75/25
(MSSNa: manufactured by Tosoh Corporation, solid content 20% by weight), and an average molecular weight of 5000 and a molar ratio (MAA / SSNa)
75/25 (MSSNa: manufactured by Tosoh Corporation, solid content 20% by weight) was used.

The polyacrylic acid-polystyrene sodium sulfonic acid copolymer (ASSNa) has an average molecular weight of 3000 and a molar ratio of polyacrylic acid part (AA) to polystyrene sodium sulfonic acid part (SSNa) (AA / SSNa). 5
0/50 (ASSNa: manufactured by Tosoh Corporation, solid content 2)
0% by weight).

Further, as a carboxyl group-containing water-soluble polymer other than the acid / acid copolymer, polyacrylic acid having an average molecular weight of 60000 (PAA: Accumer 1510 manufactured by Rohm and Haas Co., solid content 25% by weight), and an average molecular weight 1000
No. 00 polyacrylic acid-polyvinyl alcohol copolymer (PAA-PVA: Poval SPC-20A manufactured by Shin-Etsu Chemical Co., Ltd.)
Solids 99% by weight).

Further, as another water-soluble polymer, polyethylene glycol having an average molecular weight of 3000 (PEG3000:
Nippon Oil & Fats Co., Ltd. PEG4000, solid content 100% by weight), polyethylene glycol having an average molecular weight of 19000 (PEG190
00: PEG 20000 (manufactured by NOF Corporation, solid content: 100% by weight) and ammonium salt of carboxymethyl cellulose (CMC-NH ₃ : DL-10N manufactured by Daicel Chemical Industries, Ltd.) were used.

As a crosslinking agent, a zirconium compound (Zr: Baycoat 20, manufactured by Nippon Light Metal Co., Ltd., ZrO ₂
20% by weight) and polyethyleneimine having an average molecular weight of 70,000 (PI: Epomin P-1000 manufactured by Nippon Shokubai Kagaku Co., Ltd., solid content concentration: 30% by weight). Further, aqueous ammonia (NH ₃ aq: 28% by weight as ammonia) was used.

Using water as the aqueous medium, the polymethacrylic acid-polystyrene sodium sulfonate copolymer (MSSNa), polyacrylic acid-polystyrene sodium sulfonate copolymer (ASSNa), containing carboxyl groups in the proportions shown in Table 1 A water-soluble polymer, another water-soluble polymer, a cross-linking agent, and ammonia water were blended to form a bath, and the hydrophilic surface treatment compositions of Examples 1 to 12 and Comparative Examples 1 to 3 were prepared.

[Formation of hydrophilic surface-treated film] A degreasing solution (concentration: 20 g / l, 60 ° C.) prepared using an alkaline degreasing agent (Surf Cleaner 53 manufactured by Nippon Paint Co., Ltd.)
Using an aluminum plate (JIS A 1100, thickness 105μ)
The surface of m) was degreased and washed for 5 minutes, then washed with water and dried. Next, a coating type chromate paint (Surfalcoat 427 manufactured by Nippon Paint Co., Ltd.) was applied to the degreased aluminum plate using a bar coater to a film thickness of 0.1 μm.
And dried at 200 ° C. for 20 seconds to form a corrosion-resistant film.

Each of the above Examples 1 to 12 and Comparative Example 1 was applied to the aluminum plate having the corrosion-resistant coating thus obtained.
Film thickness of 0.5 after drying the hydrophilic surface treatment composition
μm, and then dried at 230 ° C. for 20 seconds to obtain test pieces having the hydrophilic surface-treated films of Examples 1 to 12 and Comparative Examples 1 to 3 on the corrosion-resistant film.

[Evaluation Test] The obtained hydrophilic surface-treated films of Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated for initial hydrophilicity and durability of hydrophilicity. For the initial hydrophilicity, each test piece was immersed in a volatile press oil (Daphne Punch Oil AF2C manufactured by Idemitsu Kosan Co., Ltd.), then pulled up, drained, and then dried at 180 ° C. for 3 minutes.
The contact angle was measured by a droplet method using a contact angle meter (CA-A type manufactured by Kyowa Interface Chemical Co., Ltd.) and evaluated.

The persistence of hydrophilicity can be measured by immersing a test piece for which the initial contact angle has been measured in pure water for 120 hours, drying it at room temperature, and measuring the contact angle with a contact angle meter (manufactured by Kyowa Interface Chemical Co., Ltd.). (CA-A type) by the droplet method and evaluated.
Furthermore, the evaluation of hydrophilicity and its persistence was performed by a four-step evaluation in which the contact angle was 10 degrees or less, ◎; 11 to 30 degrees, ○; 31 to 40 degrees, Δ; Table 1 shows the results.

[0039]

[Table 1]

As is clear from the results shown in Table 1, the hydrophilic surface-treated films formed using the hydrophilic surface-treated compositions of the present invention shown in Examples 1 to 12 all have initial hydrophilicity and hydrophilicity. The sustainability was both ○ or ◎, which proved to be excellent in hydrophilicity.

On the other hand, when the content of MSSNa exceeds 90% by weight in terms of solid content (Comparative Example 1), the film is repelled and cannot be formed into a film. Less than 1% by weight in terms of minutes (Comparative Example 2)
Was found to be inferior in hydrophilicity, and was also inferior in hydrophilicity when MSSNa was not used (Comparative Example 3).

[0042]

According to the hydrophilic surface treatment composition and hydrophilic surface treatment film of the present invention, there is no foaming during the hydrophilic treatment operation, no problem of mold abrasion and odor generation, and the surface of the material to be coated. Excellent hydrophilicity, especially on metal surfaces such as fin materials for heat exchange made of aluminum or its alloys, and on plastic surfaces and glass surfaces for the purpose of anti-fog treatment and antistatic treatment of various plastic products and glass products Gender and its persistence.

Claims (4)

[Claims] 1. A hydrophilic surface treatment composition comprising a copolymer of poly (meth) acrylic acid or a salt thereof and polystyrenesulfonic acid or a salt thereof in an amount of 1 to 90% by weight in terms of solid content. 2. A carboxyl group-containing water-soluble polymer other than a copolymer comprising poly (meth) acrylic acid or a salt thereof and polystyrenesulfonic acid or a salt thereof is converted to a solid content of 1%.
The hydrophilic surface-treating composition according to claim 1, which contains about 90% by weight. 3. A hydrophilic surface-treated film containing a copolymer of poly (meth) acrylic acid or a salt thereof and polystyrenesulfonic acid or a salt thereof in a range of 1 to 90% by weight. 4. A hydrophilic surface-treated film according to claim 3, which is formed on the surface of a material to be coated using the hydrophilic surface-treated composition according to claim 1.