JP2009126948A - Hydrophilizing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrophilizing agent imparting excellent initial hydrophilicity and hydrophilicity sustention and excellent odor resistance to a metallic material surface. <P>SOLUTION: The hydrophilizing agent comprises a block copolymer of a polyvinyl alcohol resin block having a mercapto group and a polyanionic resin block obtained by polymerizing a polymerizable monomer having at least one carboxyl group and/or sulfonic acid group in one molecule, and a polyacrylic acid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrophilic treatment agent and a hydrophilic treatment method using the hydrophilic treatment agent.

  In evaporators and heat exchangers used in air conditioners, automotive air conditioners, etc., aluminum fins are usually held at narrow intervals in order to secure the heat exchanger surface area as large as possible. It has a complicated structure in which aluminum tubes for supply are intricately arranged. Moisture in the air adheres to the fin surface as condensed water during the operation of the indoor air conditioner or car air conditioner, but at this time, the condensed water becomes substantially hemispherical water droplets on the fin surface with poor water wettability, The existence of a bridge between the fins increases the ventilation resistance. Thus, the poor wettability of the fin surface, that is, the lack of hydrophilicity, lowers the heat exchange efficiency and thus directly leads to product claims.

  Aluminum-based metal materials including aluminum and its alloys are inherently excellent in corrosion resistance, but if condensed water stays on the fin surface using the material for a long time, an oxygen concentration cell is formed. Contaminating components gradually adhere and concentrate to promote hydration and corrosion reactions. This corrosion product accumulates on the fin surface and hinders heat exchange, and is especially problematic during warm-up operation because it is discharged from the air outlet as white fine powder.

  Further, segregated materials such as aluminum-based oxides and brazing aluminum-silicon alloys formed in the heat exchanger manufacturing process remain on the fin surface, so that white rust mainly composed of aluminum oxide is formed on the fin surface. This white rust was one of the causes of deterioration of the heat exchanger. Further, white rust adsorbs moisture, and mold growth and adsorption of odorous substances (for example, cigarettes, sweat, perfume, etc.) are likely to occur, and unpleasant odors resulting from these may be brought into buildings and automobiles. It was a problem.

In order to solve the above problems, the fin surface has been conventionally hydrophilized for the purpose of imparting hydrophilicity, water wettability, corrosion resistance, odor resistance, etc. to the aluminum fin surface.
For example, Patent Document 1 proposes a hydrophilizing agent containing a predetermined polyvinyl alcohol, a salt of a phosphoric acid compound of Ca, Al, Mg, Fe and Zn, a salt of boric acid, and the like. However, although the hydrophilic treatment agent exhibits a certain degree of hydrophilicity and odor resistance, it is hardly soluble in water because the predetermined polyvinyl alcohol used is a highly crystalline resin, and the hydrophilic treatment agent is used for solubilization. It was necessary to dissolve by heating at the time of manufacturing, which had hindered production efficiency at the time of manufacturing.
Patent Document 2 discloses hydrophilicity obtained by copolymerization of a predetermined monomer, hydrophilicity that can maintain initial hydrophilicity for a long period of time even after a contaminant is attached, and hydrophilicity that is excellent in adhesion. A crosslinkable resin fine particle that forms a film and a hydrophilizing agent using the same have been proposed. However, the hydrophilic treatment agent is excellent in initial hydrophilicity, hydrophilic sustainability, and adhesion, but is not sufficient in terms of odor resistance.

Patent Document 3 discloses an aluminum heat exchanger treated with a mixed aqueous solution of polyvinyl alcohol, a water-soluble polymer, and a water-soluble crosslinking agent, and a method for producing the same. However, the resin film formed with the mixed aqueous solution has a property of absorbing water and easily hydrogels, so that it is not sufficient in terms of odor resistance.
Patent Document 4 proposes a method for producing a block copolymer containing a predetermined polyvinyl alcohol-based polymer as one component, and the copolymer comprises a coating agent such as a metal surface coating agent and an antifogging agent, and a hydrophobic property. This suggests that it can be used as a hydrophilicity imparting agent for resins. However, application to these uses is limited to general disclosure, and there is no description about the use as a resin composition used for a hydrophilization treatment agent on the surface of an aluminum-based metal. It has not been known that it is useful as a hydrophilic treatment agent having excellent properties and odor resistance.

JP 2002-285139 A JP 2005-2151 A JP-A-6-26381 JP 59-189113 A

  Under such circumstances, the present invention can impart excellent initial hydrophilicity and hydrophilic sustainability and excellent odor resistance to the surface of metal materials other than aluminum-based materials as well as aluminum-based materials. An object of the present invention is to provide a hydrophilic treatment agent and a hydrophilic treatment method using the same.

  As a result of intensive research to achieve the above object, the present inventors have solved the above object with a predetermined block copolymer containing a polyvinyl alcohol resin block and the like, and a hydrophilizing agent containing polyacrylic acid. I found that I could do it.

That is, the present invention
(1) A block copolymer of a polyvinyl alcohol resin block having a mercapto group and a polyanion resin block obtained by polymerizing a polymerizable monomer having at least one carboxyl group and / or sulfonic acid group in one molecule, and polyacryl A hydrophilizing agent containing an acid,
(2) The above (1) in which the content of the block copolymer is 10 to 95% by mass (resin solids conversion) and the polyacrylic acid content is 5 to 90% by mass (resin solids conversion). ) The hydrophilization treatment agent according to
(3) The block copolymer is obtained by radical polymerization of a polymerizable monomer in the presence of a polyvinyl alcohol resin having a mercapto group at one end, and the content of the polyanion resin block in the block copolymer is The hydrophilizing agent according to (1) or (2) above, which is 10 to 98% by mass (resin solids conversion),
(4) The hydrophilizing agent according to any one of (1) to (3) above, further containing 1 to 35% by mass (in terms of resin solid content) of crosslinkable resin fine particles, and (5) the above (1) The hydrophilization treatment method according to any one of to (4), wherein the surface of the aluminum metal material is hydrophilized by treating the surface of the aluminum metal material,
Is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrophilic treatment agent which can provide the outstanding initial hydrophilic property and hydrophilic property persistence, and the outstanding odor resistance to the metal material surface can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, the term “hydrophilic” means a broad meaning of hydrophilicity including initial hydrophilicity and hydrophilicity after time (hydrophilic sustainability) unless otherwise specified.

  The hydrophilic treatment agent of the present invention comprises a block copolymer of a polyvinyl alcohol resin block having a mercapto group and a polyanion resin block obtained by polymerizing a polymerizable monomer having at least one carboxyl group and / or sulfonic acid group in one molecule. It contains a polymer and polyacrylic acid.

[Block copolymer]
The block copolymer used in the present invention comprises a polyvinyl alcohol resin block having a mercapto group and a polyanion resin block obtained by polymerizing a polymerizable monomer component having at least one carboxyl group and / or sulfonic acid group in one molecule. Is a block copolymer.
In the hydrophilic treatment agent of the present invention, the content of the block copolymer is preferably a lower limit of 10% by mass and an upper limit of 95% by mass, more preferably a lower limit of 30% by mass and an upper limit of 70% by mass. The lower limit is 40% by mass and the upper limit is 60% by mass, and the lower limit is 45% by mass and the upper limit is 55% by mass.
The content of the polyvinyl alcohol resin block in the block copolymer is, in terms of resin solid content, the lower limit is preferably 2% by mass and the upper limit is preferably 90% by mass, the lower limit is 2% by mass, and the upper limit is 30% by mass. More preferably. When the content of the polyvinyl alcohol resin block is within the above range, the film forming property of the polyvinyl alcohol resin block is expressed, so that the formed hydrophilic film can maintain the film state. Adhesion is good and hydrophilicity lasts longer.
The content of the polyanion resin block in the block copolymer is preferably 10% by mass at the lower limit and 98% by mass at the upper limit in terms of resin solids, and is 70% by mass and 95% by mass at the upper limit. It is more preferable that When the content of the polyanion resin block is within the above range, a hydrophilic film having excellent hydrophilicity and excellent odor resistance can be obtained.

[Block copolymer: polyvinyl alcohol resin block]
The polyvinyl alcohol resin having a mercapto group at one end used in the present invention is, for example, in the presence of thiolic acid such as thiol acetic acid, thiol propionacetic acid, thiol butyric acid, thiol valeric acid, etc., for example, vinyl formate, vinyl acetate, propion It can be obtained by saponifying a polyvinyl ester polymer obtained by polymerizing vinyl monomers such as vinyl acid vinyl, versatic acid vinyl, vinyl laurate, vinyl stearate, vinyl benzoate and the like. It is also possible to use a commercially available product, for example, a trade name “Kuraray M Polymer” (manufactured by Kuraray Co., Ltd.).

[Block copolymer: polyanion resin block]
The polyanion resin block according to the present invention is a resin block formed by polymerizing a polymerizable monomer having at least one carboxyl group and / or sulfonic acid group in one molecule.
Examples of the polymerizable monomer having a carboxyl group and / or a sulfonic acid group include vinyl esters such as vinyl formate, vinyl acetate and vinyl propionate; alkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ( (Meth) acrylic acid esters such as dimethylaminoethyl acrylate and quaternized compounds thereof; 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sulfoalkyl (meth) acrylate, allylsulfonic acid, vinylsulfonic acid And sodium salt thereof, p-styrenesulfonic acid and sodium salt and / or potassium salt thereof, and the like. These may be used alone or in combination.

  Preferred examples of the polymerizable monomer having a carboxyl group and / or a sulfonic acid group include AMPS, acrylic acid, 2-hydroxyethyl (meth) acrylate and the like, and among them, AMPS and acrylic acid are preferable. When the polymerizable monomer contains AMPS, the lower limit of the content of AMPS in the polymerizable monomer is preferably 40% by mass and the upper limit is 100% by mass, the lower limit is 50% by mass, and the upper limit is 80% by mass. The lower limit is more preferably 60% by mass, and the lower limit is particularly preferably 75% by mass. When the content of AMPS in the polymerizable monomer is within the above range, a film excellent in hydrophilicity and odor resistance can be obtained.

[Block copolymer: production method]
The block copolymer used in the present invention can be obtained by a generally known polymerization method, and is preferably obtained by radical polymerization of a polymerizable monomer component in the presence of a polyvinyl alcohol resin having a mercapto group at one end. The radical polymerization is preferably performed in a solvent that can dissolve the polyvinyl alcohol resin, for example, a medium mainly composed of water, dimethyl sulfoxide, or the like. Moreover, as a polymerization system, well-known things, such as a batch type, a semi-continuous type, a continuous type, are mentioned.

In radical polymerization, a commonly used radical polymerization initiator can be used, for example, persulfates such as potassium persulfate and ammonium persulfate; 2,2′-azobis- (2,4-dimethylvaleronitrile), 2 Azo compounds such as 2,2′-azobisbutyronitrile; peroxides such as methyl ethyl peroxide, di-t-butyl peroxide and acetyl peroxide; hydrogen peroxide, potassium bromate and the like.
When polymerization is carried out in an aqueous system, it is preferable to use an oxidizing agent such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or potassium bromate. Among them, potassium bromate does not generate radicals under normal polymerization conditions. Since it decomposes only by a redox reaction with a mercapto group at one end in the polyvinyl alcohol resin to generate a radical, it is preferable for preparing the block copolymer according to the present invention.

  When radically polymerizing a polymerizable monomer component in the presence of a polyvinyl alcohol resin having a mercapto group at one end, the polymerization system is preferably acidic, and all polymerization operations are preferably pH 6 or less, more preferably pH 4 or less. To implement. If it exists in this range, superposition | polymerization efficiency can be kept favorable.

[Crosslinkable resin fine particles]
The hydrophilic treatment agent of the present invention preferably further contains crosslinkable resin fine particles.
As the crosslinkable resin fine particles used in the present invention, generally used organic resin fine particles can be used. For example, acrylic resin, melamine resin, polycarbonate resin, urethane resin, urea resin, benzoguanamine resin, benzoguanamine- Fine particles such as melamine-formaldehyde condensate can be mentioned. Moreover, as crosslinkable resin fine particles, the monomer (a) represented by the following formula (1) is 30 to 95% by mass, the polyoxyalkylene chain represented by the following formula (2) and / or the following formula (3). And a monomer (b) having a polymerizable double bond (5) to 60% by mass, and a resin obtained by copolymerizing monomer components (0) to 50% by mass containing (meth) acrylic acid Particular preference can be given to fine particles using.

  The crosslinkable resin fine particles represented in this way are obtained by reacting a methylol group or ethylol group of the following monomer (a) with a functional group such as a carboxyl group or a hydroxyl group of the following monomer (b), or between methylol groups or ethylol groups. May form a water-insoluble strong hydrophilic film when used as a component of the hydrophilizing agent of the present invention, because of the condensation reaction or the reaction with the carboxyl group or hydroxyl group of the following monomer (c). Can do. In addition, since the crosslinkable resin fine particles are highly hydrophilic and have a relatively large number of unreacted functional groups, when used as a component of the hydrophilic treatment agent of the present invention, by reacting with other hydrophilic resins, The hydrophilicity is not impaired and the persistence of hydrophilicity after contamination can be greatly improved. Furthermore, since the crosslinkable resin fine particles have a relatively small swelling rate with respect to water, it is possible to prevent the formed hydrophilic film from being dissolved in water.

[Crosslinkable resin fine particles: monomer (a)]
The monomer (a) is a monomer represented by the following formula (1).

Here, in the formula, R ¹ represents hydrogen or a methyl group. R ² represents CH ₂ or C ₂ H ₄ . The monomer represented by the formula (1) is N-methylolacrylamide, N-methylolmethacrylamide, N-hydroxyethylacrylamide or N-hydroxyethylmethacrylamide. In the case where the monomer (a) represented by the above formula (1) is used, when a hydrophilic treatment agent containing the resulting crosslinkable resin fine particles is used, a film excellent in hydrophilic sustainability and adhesion is formed. Can do. These may be used alone or in combination of two or more.

[Crosslinkable resin fine particles: monomer (b)]
The monomer (b) is preferably a monomer having a polyoxyalkylene chain and a polymerizable double bond represented by the following formula (2) and / or (3). The monomer (b) imparts excellent water dispersion stability and hydrophilicity to the crosslinkable resin fine particles.

  Formula (2) which is a preferable embodiment of the monomer (b) is represented as follows.

Here, in the formula, R ³ and R ⁴ may be the same or different and each represents hydrogen or a methyl group. R ⁵ represents hydrogen, a methyl group, SO ₃ H, SO ₃ Na or SO ₃ NH ₄ . n represents an integer of 6 to 300, the lower limit is 30, and the upper limit is preferably 200. Within this range, the dispersion stability and hydrophilicity are good, and the crosslinkable resin fine particles can be easily prepared.

  Moreover, Formula (3) which is a preferable aspect of a monomer (b) is represented as follows.

Here, in the formula, R ⁶ and R ⁸ may be the same or different and each represents hydrogen or a methyl group. R ⁹ represents hydrogen, methyl, SO ₃ H, the SO ₃ Na or SO ₃ NH _4. R ⁷ is CH ₂ or the following chemical formula;

を表す。ｍは、６〜３００の整数を表す。分散安定性、及び親水性の観点から、下限は３０であることが好ましく、上限は２００であることが好ましい。

Represents. m represents an integer of 6 to 300. From the viewpoint of dispersion stability and hydrophilicity, the lower limit is preferably 30, and the upper limit is preferably 200.

  Examples of the monomer (b) include methoxypolyethylene glycol monomethacrylate, methoxypolyethyleneglycol monoacrylate, octoxypolyethyleneglycol-polypropyleneglycol monoacrylate and the like in addition to the above-described compounds. These may be used alone or in combination of two or more.

  Further, the monomer (b) preferably contains 50% by mass or more of polyoxyalkylene chain, and more preferably contains a lower limit of 80% by mass and an upper limit of 99% by mass. Here, for example, 50% by mass or more means that the total solid mass of the polyoxyalkylene chain portion is 50% by mass or more in 100% by mass of the total solid content of the monomer (b) used. . If it is in the said range, the hydrophilic property of a hydrophilic film will not fall.

[Crosslinkable resin fine particles: monomer (c)]
The monomer (c) is a compound that has a polymerizable unsaturated bond in one molecule and can be copolymerized with the monomer (a) represented by the formula (1) and the monomer (b). It is not limited. Examples of the monomer (c) include carboxylic acid groups such as (meth) acrylic acid and maleic acid, vinyl monomers such as vinyl acetate groups, hydroxyl groups such as 2-hydroxyethyl acrylate, N-vinylacetamide, and N-vinylformamide. , N-vinylpyrrolidone, N-vinylimidazole, acrylonitrile, methyl (meth) acrylate, styrene, unsaturated double bond-containing surfactant, (meth) acrylamide, N-methylacrylamide, N-vinylsulfonic acid, N- Examples include allyl sulfonic acid, styrene sulfonic acid soda, and 2-acrylamide 2-methylpropane sulfonic acid. Moreover, the unsaturated monomer used for normal radical polymerization, such as (meth) acrylic acid esters other than methyl (meth) acrylate, is also illustrated. Among these, (meth) acrylic acid is preferable because the hydrophilicity of the resulting crosslinkable fine particles can be improved. These may be used alone or in combination of two or more.

The content of the monomer (a) in the crosslinkable resin fine particles is preferably a lower limit of 30% by mass and an upper limit of 95% by mass, more preferably a lower limit of 30% by mass and an upper limit of 90% by mass, and a lower limit of 40% by mass. The upper limit is more preferably 80% by mass. If the content of the monomer (a) in the crosslinkable resin fine particles is within the above range, the hydrophilic durability after the contamination of the hydrophilic film formed by the hydrophilizing agent is not lowered, and excellent adhesion is obtained. In addition, the production of the crosslinkable resin fine particles is facilitated.
The content of the monomer (b) in the crosslinkable resin fine particles is preferably a lower limit of 5% by mass and an upper limit of 60% by mass, and more preferably a lower limit of 10% by mass and an upper limit of 40% by mass. If it exists in the said range, the dispersibility of the crosslinkable fine particle in a hydrophilic treatment agent can be kept favorable, and the hydrophilicity of the hydrophilic film which a hydrophilic treatment agent forms can be made excellent. Moreover, since the adhesiveness of the hydrophilic film becomes good, the hydrophilic durability after contamination becomes excellent.
In addition, the content of the monomer (c) in the crosslinkable resin fine particles is preferably a lower limit of 0% by mass and an upper limit of 50% by mass, and more preferably an upper limit of 30% by mass. If it exists in this range, the hydrophilic durability after the contamination of the hydrophilic film which a hydrophilic treatment agent forms can be prevented from falling, without the hydrophilic property and crosslinking property of the crosslinkable resin fine particle obtained falling.

  The crosslinkable resin fine particles used in the present invention preferably have a water swelling ratio of 1.5 or less. By setting the water swelling rate within the above range, even when the hydrophilic film is exposed to moisture when the hydrophilic film is formed, a decrease in the adhesion of the film is suppressed. A water swelling ratio of 1.5 or less is obtained by appropriately setting the reaction conditions for the monomer (a), the monomer (b), and the monomer (c) represented by the above formula (1) with the above-described blending ratio. be able to. The water swelling rate is more preferably a lower limit of 1.0 and an upper limit of 1.3. Here, the water swelling ratio is a value calculated as water swelling ratio = particle diameter in aqueous solution / average particle diameter in solvent. Moreover, an average particle diameter is the value measured using the electrophoretic light-scattering photometer photoELS-800 (made by Otsuka Electronics Co., Ltd.).

[Crosslinkable resin fine particles: production method]
The crosslinkable resin fine particles used in the present invention include, for example, N-methylol (meth) acrylamide 30 to 95% by mass, monomer (b) 5 to 60% by mass having a polyoxyalkylene chain and a polymerizable double bond, and monomer (C) 0 to 50% by weight in a water-miscible organic solvent or a water-miscible organic solvent that dissolves the monomers used but does not substantially dissolve the resulting copolymer in the absence of a dispersion stabilizer. It can be produced by polymerizing in a water mixed solvent.

  The copolymerization of the monomer component consisting of the monomer (a), the monomer (b), and the monomer (c) is usually performed in the presence of a radical polymerization initiator. It does not specifically limit as said radical polymerization initiator, All the normally used can be used, The thing similar to what is used in superposition | polymerization of a block copolymer can be used. The amount used can usually be in the range of 0.2 to 5 mass% with respect to the monomer component.

In the production of the crosslinkable fine particles of the present invention, the copolymerization of the monomer component consisting of the monomer (a), the monomer (b) and the monomer (c) The reaction can be performed in a solvent such as an ether solvent, methoxypropanol, or a mixed solvent of these with water.
In the polymerization in the production of the crosslinkable fine particles, a dispersant may be used in combination. Examples of the dispersant include dispersion resins such as polyvinyl pyrrolidone, polyvinyl alcohol, and polycarboxylic acid, and anionic, cationic, and nonionic surfactants.

  The polymerization temperature in the above copolymerization can be changed depending on the type of polymerization initiator used, but a temperature within the range of a lower limit of 70 ° C. and an upper limit of 140 ° C. is usually appropriate. If it is less than 70 ° C., the crosslinkability becomes insufficient, and if it exceeds 140 ° C., it is difficult to control the reaction. The lower limit is more preferably 90 ° C, and the upper limit is more preferably 120 ° C. The reaction time is usually 0.2 to 5 hours. If it is less than 0.2 hours, the crosslinkability becomes insufficient, and even if it exceeds 5 hours, the reaction does not change, which is economically disadvantageous. By setting the polymerization temperature to 90 ° C. or higher, the intraparticle crosslinking can be advanced. When the polymerization temperature is less than 70 ° C., the intra-particle crosslinking reaction usually hardly proceeds during the polymerization. Therefore, after the polymerization reaction, the resulting polymer is usually heated at a temperature of 90 ° C. or more for 0.2 to 5 hours. An operation for advancing intra-particle crosslinking is performed.

  In addition, a crosslinking reaction catalyst may be added to the polymerization reaction system as necessary in order to advance the intraparticle crosslinking reaction of the polymer particles during or after the polymerization reaction more quickly. Examples of the crosslinking reaction catalyst include strong acid catalysts such as dodecylbenzenesulfonic acid and paratoluenesulfonic acid; and polymerizable double bond-containing strong acid catalysts such as sulfoethyl methacrylate.

  The particle diameter of the crosslinkable resin fine particles thus obtained is not particularly limited, but is generally within the range of 0.03 to 1 μm, preferably 0.05 to 0.6 μm from the viewpoint of the stability of the crosslinkable resin fine particles. It is. The particle diameter is a value measured using an electrophoretic light scattering photometer photo ELS-800 (manufactured by Otsuka Electronics Co., Ltd.).

[Polyacrylic acid]
The hydrophilic treatment agent of the present invention contains polyacrylic acid. The polyacrylic acid may be a homopolymer or a copolymer. The other monomer used in the case of the copolymer is not particularly limited as long as it is copolymerizable with acrylic acid, but is preferably a hydroxyalkyl ester or alkyl ester of acrylic acid.
Moreover, when polyacrylic acid is a copolymer, the content of polyacrylic acid in the copolymer is preferably 20 to 100% (mol basis), and more preferably 80 to 100% (mol basis). If it exists in the said range, the hydrophilic durability of a hydrophilic membrane | film | coat and the fall of adhesiveness can be suppressed.

The polyacrylic acid preferably has an acid value of 200 mgKOH / g or more or a hydroxyl value of 200 mgKOH / g or more. Thereby, the hydrophilic sustainability and adhesiveness of the formed hydrophilic film can be further improved. The acid value of the polyacrylic resin is preferably a lower limit of 200 mgKOH / g and an upper limit of 800 mgKOH / g, and the hydroxyl group is preferably a lower limit of 200 mgKOH / g and an upper limit of 1500 mgKOH / g.
As such polyacrylic acid, what was manufactured by the well-known method can also be used, and a commercial item ("Jurimer (brand name)": Nippon Pure Chemical Co., Ltd. product etc.) may be used.

[Other hydrophilic resins]
The hydrophilic treatment agent of the present invention can further contain other hydrophilic resin.
Other hydrophilic resins are not particularly limited as long as they are hydrophilic resins. For example, unsaturated polymerizable monomers or unsaturated polymerizable aqueous polymer compounds containing carboxyl groups and / or hydroxyl groups, carboxyl groups and / or Or a natural polymer compound or a derivative thereof containing a hydroxyl group, an aqueous alkyd resin, an aqueous polyester resin, an aqueous polybutadiene resin, an aqueous polyamide resin, an aqueous epoxy resin, an aqueous polyurethane resin, an aqueous phenol resin, an aqueous amino resin, a polyether resin, Examples include polyacrylic acid (methacrylic acid) modified products (including derivatives).

Examples of the unsaturated polymerizable monomer or unsaturated polymerizable aqueous polymer compound containing a carboxyl group and / or a hydroxyl group include, for example, polyvinyl alcohol such as polyvinyl alcohol partially saponified polyvinyl acetate resin and the block copolymer Examples include polyvinyl alcohol derivatives other than coalescence, polyvinyl pyrrolidone, and the like.
Examples of the polyvinyl alcohol derivative other than the block copolymer include polyoxyethylene-modified polyvinyl alcohol having a structure in which a polyoxyethylene chain such as polyoxyethylene is grafted on a part of hydroxyl groups in the polyvinyl alcohol. Specifically, a trade name “Ecomatey WO-320RN” (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) can be mentioned.
Examples of the natural polymer compound or derivative thereof containing a carboxyl group and / or a hydroxyl group include cellulose derivatives such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and methyl cellulose (MC), and methyl cellulose derivatives. Can do.
Examples of the modified polyacrylic acid (methacrylic acid) (including derivatives) include sodium salts, potassium salts, ammonium salts, acrylates (acrylic acid esters), and alkoxy acrylates.

The hydrophilic resin is preferably at least one selected from polyvinyl alcohol derivatives other than polyvinyl alcohol and the block copolymer, cellulose derivatives, and polyacryl-modified products (including derivatives). Thereby, the hydrophilic sustainability and adhesiveness of the formed hydrophilic film can be further improved.
The acid value of these hydrophilic resins is preferably a lower limit of 200 mgKOH / g and an upper limit of 800 mgKOH / g. If it exists in this range, the hydrophilic durability of a hydrophilic membrane | film | coat and the fall of adhesiveness can be suppressed. Further, the hydroxyl group of the hydrophilic resin is preferably the lower limit of 200 mgKOH / g and the upper limit of 1500 mgKOH / g for the same reason.

[Hydrophilic treatment agent]
The hydrophilization treatment agent of the present invention is a block copolymer comprising a polyvinyl alcohol resin block having a mercapto group obtained as described above and a polyanion resin block obtained by polymerizing a polymerizable monomer component, a polyacrylic resin, In addition, the crosslinkable resin fine particles, hydrophilic resin, various additives and the like blended as necessary are blended according to a conventionally known method so as to have the following contents.

  The content of the block copolymer in the hydrophilic treatment agent of the present invention is preferably 10% by mass lower limit and 95% by mass upper limit in terms of resin solid content, more preferably 30% by mass and 70% by mass upper limit. Preferably, the lower limit is 40% by mass and the upper limit is 60% by mass, and the lower limit is 45% by mass and the upper limit is 55% by mass. The content of polyacrylic acid in the hydrophilic treatment agent is preferably 5 to 90% by mass in terms of resin solid content, more preferably a lower limit of 10% by mass and an upper limit of 70% by mass, and a lower limit of 30% by mass and an upper limit of 40% by mass. Is more preferable.

When the hydrophilization treatment agent contains crosslinkable resin fine particles, the content is more preferably a lower limit of 1% by mass and an upper limit of 35% by mass, and a lower limit of 5% by mass and an upper limit of 20% by mass in terms of resin solid content. Preferably, the lower limit is 10% by mass and the upper limit is 15% by mass.
Moreover, when a hydrophilic treatment agent contains other hydrophilic resin, the content is 5-30 mass% in conversion of resin solid content in a hydrophilic treatment agent, a minimum is 10 mass%, and an upper limit is 25 mass%. The lower limit is more preferably 15% by mass and the upper limit is more preferably 25% by mass. If content of other hydrophilic resin exists in the said range, the fall of the hydrophilic sustainability of a hydrophilic membrane | film | coat and the processability of a hydrophilic treatment agent can be suppressed.

  The hydrophilic treatment agent of the present invention can be used by dissolving in a solvent. The content in the hydrophilizing agent is preferably 1 to 50% by mass, more preferably 5% by mass and the upper limit is 30% by mass in terms of workability and economy in terms of resin solid content.

  The solvent is not particularly limited, but a solvent mainly containing water is preferable from the viewpoint of waste liquid treatment. Further, a solvent may be used in combination in order to improve the film forming property and form a more uniform and smooth film. Such a solvent is not particularly limited as long as it is generally used in paints and can be uniformly mixed with water, and examples thereof include alcohol-based, ketone-based, ester-based and ether-based organic solvents. Can do.

  The hydrophilic treatment agent of the present invention may be added with a necessary amount of other components depending on the function to be added. For example, surfactants, colloidal silica, titanium oxide, saccharides and other hydrophilic additives; tannic acid, imidazoles, triazines, triazoles, guanines, hydrazines, phenol resins, zirconium compounds, silane coupling agents, etc. Rust additive; Melamine resin, epoxy resin, blocked isocyanate, amine, phenolic resin, silica, aluminum, zirconium and other crosslinking agents; antibacterial agent, fungicide, preservative, dispersant, lubricant, deodorant, solvent, Examples thereof include pigments, dyes, antibacterial agents, antioxidants, surface roughening materials, and inhibitors for imparting corrosion resistance.

  The hydrophilic treatment agent of the present invention thus obtained is applied to the surface of the metal material, so that it has excellent hydrophilicity on the surface of the metal material and long-term hydrophilic durability (hydrophilic durability), excellent It is possible to form a hydrophilic film capable of imparting high odor resistance and excellent storage stability. The hydrophilic treatment agent of the present invention can be preferably used for aluminum or an alloy thereof among metal materials, and more preferably, an evaporator used for an air conditioner, an air conditioner for automobiles, a metal fin of a heat exchanger, and the like. Is preferably used for aluminum fins.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.

[Preparation of block copolymer]
Synthesis example 1
In a glass reaction vessel equipped with a stirrer and a nitrogen air supply tube, 5 parts by mass of polyvinyl alcohol having a mercapto group at one end (manufactured by Kuraray Co., Ltd., product name: Kuraray M Polymer M-205) in terms of solid content is added in a nitrogen atmosphere It melt | dissolved in 500 mass parts of ion-exchange water at 70 degreeC. Maintaining this at 70 ° C., a monomer aqueous solution in which 20 parts by mass of acrylic acid (AA) and 75 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) are dissolved in 300 parts by mass of ion-exchanged water, In addition, an ammonium persulfate aqueous solution dissolved in 50 parts by mass of pure water as a polymerization initiator was dropped from another port over 90 minutes, and further heated and stirred for 1 hour for polymerization. A mass% block copolymer was obtained.
The polyvinyl alcohol used had an average degree of polymerization of 500 and a degree of saponification of 88 mol%, and the amount of mercapto group in the polyvinyl alcohol determined by the iodine oxidation method was 4.1 × 10 ⁻⁵ equivalent / g. Met.

As Synthetic Examples 2-8 and Comparative Synthetic Examples 1-3, the same as Synthetic Example 1 except that the blending amounts of the raw materials used in Synthetic Example 1 (all in terms of solid content) were changed to the conditions described in Table 1. To obtain a block copolymer.
In Comparative Synthesis Example 1, polyvinyl alcohol containing no mercapto group (trade name “Kuraray Poval”: manufactured by Kuraray Co., Ltd.) was used as the polyvinyl alcohol.

[Preparation of crosslinkable resin fine particles]
A monomer solution in which 70 parts by mass of N-methylolacrylamide and 30 parts by mass of methoxypolyethylene glycol monomethacrylate (polyethylene chain having 100 repeating units) were dissolved in 200 parts by mass of methoxypropanol, and “ACVA” (50 parts by mass of methoxypropanol) Otsuka Chemical Co., Ltd. azo initiator) A solution in which 1 part by mass was dissolved was added dropwise from another port to 150 parts by mass of methoxypropanol at 105 ° C. in a nitrogen atmosphere over 3 hours, and further heated and stirred for 1 hour. Polymerized. In the obtained dispersion, the average particle diameter of the crosslinkable fine particles was 250 nm, the water swelling ratio of the crosslinkable fine particles was 1.10, and the viscosity Ford Cup No. 4 was 17 seconds and the solid content concentration was 20% by mass. In addition, the average particle diameter of the crosslinkable fine particles was measured with photal ELS-800 (electrophoretic light scattering photometer manufactured by Otsuka Electronics Co., Ltd.) (the same measurement was performed hereinafter).

[Synthesis of polyacrylic acid]
A monomer solution in which 80 parts by mass of acrylic acid and 20 parts by mass of 2-hydroxyethyl acrylate are dissolved in 300 parts by mass of pure water is separated from a solution in which 1 part by mass of ammonium persulfate is dissolved in 50 parts by mass of pure water. From a mouth, it is dripped over 90 minutes at 70 degreeC in nitrogen atmosphere over 90 minutes, and also superposes | polymerizes by heating and stirring for 1 hour, Ion exchange water is added, 10 mass% polyacryl of resin solid content conversion is added. The acid was prepared. The obtained polyacrylic acid had a solid content acid value of 620, a solid content hydroxyl value of 110, and a weight average molecular weight of 20,000 to 100,000.
[Other hydrophilic resins]
As other hydrophilic resins, AA / AMPS copolymer (trade name “Aron A6012”, manufactured by Toa Gosei Co., Ltd.), CMC (trade name “Sunrose APP-84”: manufactured by Nippon Paper Industries Co., Ltd.) were used. .

Examples 1-16, Comparative Examples 1-8
The components obtained in the above synthesis examples and the like are mixed at a blending ratio shown in Table 2, and ion-exchanged water is added so that the resin solid content concentration shown in Table 2 is obtained. Got. The obtained hydrophilic treatment agent was evaluated by the following evaluation method. The results of evaluation of Examples 1 to 16 are shown in Table 2, and the results of evaluation of Comparative Examples 1 to 8 are shown in Table 2.

(Evaluation methods)
The hydrophilizing agent obtained in each example was evaluated by the following method.
(1) Preparation of test plate A 150 mm square (thickness: 0.13 mm) 1000 series aluminum substrate was degreased at 70 ° C. for 5 seconds using a 1% solution of Surf Cleaner EC370 (manufactured by Nippon Paint Co., Ltd.), and Alsurf 4130 ( Zirconium treatment was performed at 60 ° C. for 5 seconds using a 10% solution (manufactured by Nippon Paint Co., Ltd.). Subsequently, the hydrophilization treatment agent of each Example and Comparative Example was applied with a bar coater # 4, and heated and dried at 240 ° C. for 20 seconds to obtain a test plate.
(2) Evaluation of initial hydrophilicity (measurement of contact angle)
After the hydrophilization treatment product was brought into contact with running tap water for 72 hours, the contact angle with water droplets was measured. The water contact angle was measured using an automatic contact angle meter (model number: DSA20E, manufactured by KRUSS). It can be said that the smaller the value of the contact angle, the higher the hydrophilicity. In the present invention, the value of the water contact angle is determined to be good if it is 50 degrees or less, preferably 30 degrees or less, and more preferably 25 degrees or less.
(3) Evaluation of hydrophilic durability (measurement of contact angle)
After the test plate was brought into contact with running water for 8 hours, 5 g each of dioctyl phthalate, hexadecanol and stearic acid were added to the petri dish as contaminants, and the test plate placed in the petri dish was dried at 80 ° C. for 16 hours (contaminant Part of the water vaporized), and this flowing water contact and drying were taken as one cycle. The contact angles after 1, 5, and 10 cycles were measured to investigate hydrophilic degradation due to contamination in the atmospheric environment. The water contact angle was measured using an automatic contact angle meter (model number: DSA20E, manufactured by KRUSS), and the hydrophilicity was evaluated in the same manner as the hydrophilicity evaluation in (2) above.
(4) Evaluation of hydrophilic sustainability by immersion in ion-exchanged water In order to evaluate hydrophilic sustainability after long-term exposure to an aqueous environment, hydrophilic sustainability was evaluated in ion-exchanged water. The test plate was immersed in ion-exchanged water kept at 20 ° C. for 72 hours to 240 hours, drained, and then dried in a drier kept at 80 ° C. for 15 minutes. After the taken-out test plate was air-cooled, it was immediately measured using an automatic contact angle meter (model number: DSA20E, manufactured by KRUS), and the hydrophilicity was evaluated in the same manner as the hydrophilicity evaluation in (2) above.
(5) Evaluation of adhesion After the test plate was immersed in boiling water for 1 minute, a load of 500 g was applied and the test plate was rubbed with paper to make one reciprocation once. The number of reciprocations until the substrate of the test plate was seen was evaluated according to the following criteria.
○: 10 times or more ×: Less than 10 times (6) Evaluation of odor resistance Cigarette (product name: Mild Seven, manufactured by Japan Tobacco Inc.) is bubbled against 2 L of ion-exchanged water (14/2) Time), the smoke component was dissolved in water. After the test plate was brought into contact with running water for 12 hours, the test plate was sprayed with water in which the smoke component was dissolved, and was blown and dried for 8 minutes while blowing tobacco smoke. Thereafter, the test plate was brought into contact with running water for 2 hours and then naturally dried. A series of these steps is defined as one cycle, and five panelists evaluated the test plates after 1, 5, and 10 cycles according to the following criteria, and the average value was evaluated as odor resistance.
0: Odorless 1: Slightly smelling 2: Slightly smelling 3: Clearly smelling 4: Strong odor 5: Very strong odor

  From Table 2, the hydrophilic treatment agents obtained in Examples 1 to 16 showed excellent results in all points of initial hydrophilicity, hydrophilic durability, adhesion, and odor resistance. On the other hand, the hydrophilization treatment agents obtained in Comparative Examples 1 to 8 were all inferior to the examples in terms of hydrophilization, hydrophilic sustainability, and durability.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrophilic treatment agent which can provide the outstanding initial hydrophilic property and hydrophilic property persistence, and the outstanding odor resistance to the metal material surface can be obtained. The hydrophilizing agent of the present invention can be suitably used for hydrophilizing a metal material surface, particularly aluminum and fins for heat exchange using aluminum.

Claims (5)

  A block copolymer of a polyvinyl alcohol resin block having a mercapto group and a polyanion resin block obtained by polymerizing a polymerizable monomer having at least one carboxyl group and / or sulfonic acid group in one molecule, and polyacrylic acid Hydrophilizing agent.   The content of the block copolymer is 10 to 95% by mass (resin solid content conversion), and the content of polyacrylic acid is 5 to 90% by mass (resin solid content conversion). Hydrophilizing agent.   The block copolymer is obtained by radical polymerization of a polymerizable monomer in the presence of a polyvinyl alcohol resin having a mercapto group at one end, and the content of the polyanion resin block in the block copolymer is 10 to 98. The hydrophilizing agent according to claim 1, wherein the hydrophilizing agent is in mass% (resin solids conversion).   Furthermore, the hydrophilic treatment agent in any one of Claims 1-3 which contains 1-35 mass% (resin solid content conversion) of crosslinkable resin microparticles | fine-particles.   A method for hydrophilizing a surface of an aluminum-based metal material, comprising treating the surface of an aluminum-based metal material with the hydrophilization treatment agent according to claim 1.