JP5600081B2 - Pre-coated fin material for heat exchanger and heat exchanger - Google Patents

Description

  The present invention includes a precoat fin material for a heat exchanger provided with an excellent frosting suppressing effect and a condensed water eliminating effect on the surface of an aluminum plate made of aluminum or an aluminum alloy, and a fin structure configured using the same. It relates to a heat exchanger.

  A precoat fin material for a heat exchanger made of an aluminum plate is used as a fin material for a heat exchanger for a heat pump air conditioner by forming it into a desired fin shape. However, in the heat exchanger using the precoat fin material for heat exchanger, frost adheres to the fin surface when the air temperature is low or the refrigerant evaporation temperature is low in the outdoor unit during heating operation. When the frost is formed, the gap between the fins is closed and the ventilation resistance is increased. As a result, the amount of air flowing into the heat exchanger is decreased, and the evaporation capacity of the heat exchanger of the outdoor unit is decreased. For this reason, when frost adheres to the fin surface of the heat exchanger, it is necessary to stop the heating operation and perform the defrosting operation in order to remove the frost. It was.

  In addition, as a technique for suppressing such frost formation, there is a method of forming a water-repellent film on the surface of the fin. In this method, it is possible to extend the time for blocking by frost formation, but after defrosting or comparison When the temperature of the refrigerant is high and water droplets are condensed on the fin surface, condensed water adheres between the fins, and this condensed water forms a bridge between the fins, resulting in increased ventilation resistance. As a result, there is a problem that the heat exchange performance is lowered.

  For this reason, in order to improve the thermal efficiency of the heat exchanger during heating operation, it is required to remove the condensed water on the fin surface before frosting and to make the fin surface difficult to frost, Moreover, as means for solving this problem, a hydrophilic treatment method (Patent Documents 1 to 3) in which a hydrophilic film is formed on the fin surface and condensed water flows down as a thin water film, and a water-repellent film is formed on the fin surface. A water repellent treatment method (Patent Documents 4 to 6) for forming and removing condensed water at an early stage, and forming a water repellent film and a hydrophilic film according to the arrangement and location of the fins. Water repellent / hydrophilic treatment methods (Patent Documents 7 to 9) and the like have been proposed that compensate for the advantages and disadvantages of the conductive film.

JP 09-014,888 JP 2000-028,291 JP JP 2010-223,520 Japanese Patent Laid-Open No. 08-269,367 JP 09-026,286 JP JP 2009-270,181 Japanese Patent Laid-Open No. 08-152,287 Japanese Patent No. 3,761,262 JP 2006-046,695 gazette

  However, in the hydrophilic treatment methods of Patent Documents 1 to 3, the function of flowing down as a thin water film is not sufficient, and the defrosting property that suppresses frost formation during heating operation is not sufficient. Also in the water repellency treatment method of 4-6, the water repellency is not sufficient, the defrosting property that reliably eliminates the condensed water droplets and suppresses frost formation is not sufficient, and in Patent Documents 7-9, Water-repellent film and hydrophilic film formed according to fin arrangement and site, especially water-repellent film, water repellency performance and hydrophilic performance, especially water repellency performance is not always sufficient and satisfactory frost control effect Has not yet been achieved, and the problem of increased ventilation resistance between fins due to condensed water has not been sufficiently solved.

  In view of these problems of the prior art, the present inventors have developed a precoat fin material for heat exchangers that has an excellent frost suppression effect and a condensed water elimination effect, and uses this precoat fin material. To develop a heat exchanger with a fin structure that has no frost formation during heating operation and that does not have the problem of increased ventilation resistance between the fins due to condensed water by cooperating the frost suppression effect and the condensed water exclusion effect. As a result of intensive studies, the cross-linked water-repellent film obtained by introducing a specific cross-linked structure into the water-repellent film has excellent anti-frosting effect. It was found that a fin structure having both an excellent frost suppression effect and an excellent condensed water elimination effect can be constructed by cooperating with an excellent hydrophilic film on the surface, and the present invention was completed.

  Accordingly, an object of the present invention is to provide a precoat fin material for a heat exchanger having a cross-linked water-repellent film having an excellent frosting-inhibiting effect on one surface and a hydrophilic film having a condensate eliminating effect on the other surface. It is to provide.

  Another object of the present invention is to use a single-sided water-repellent / single-sided hydrophilic fin material made of the precoat fin material for heat exchangers, or a cross-linked water-repellent film having an excellent frosting-inhibiting effect on both sides. Using a double-sided water-repellent fin material and a double-sided hydrophilic fin material with a hydrophilic film having an excellent condensate draining effect on both sides, a cross-linked water-repellent film having an excellent frost-inhibiting effect and an excellent condensate drainage A hydrophilic film that has an effect is made to face each other and collaborate to prevent frost formation during heating operation as much as possible, and water droplets of condensed water contact the hydrophilic film under conditions where the fin surface tends to condense Accordingly, it is an object of the present invention to provide a heat exchanger having a fin structure that can quickly remove the water droplets and thereby continue a good heat exchange function without increasing the ventilation resistance.

  That is, the present invention provides a fin substrate formed of an aluminum plate made of aluminum or an aluminum alloy, a cross-linked water-repellent coating having a frost formation suppressing effect provided on one surface of the fin substrate, and the other of the fin substrate. A pre-coated fin material for a heat exchanger provided with a hydrophilic film having an effect of eliminating condensed water provided on the surface, wherein the crosslinked water-repellent film is selected from the group consisting of perfluoroalkyl groups and perfluoroalkenyl groups A resin having at least one fluorine atom-containing group (A), a quaternary ammonium base-containing modified epoxy resin (B) and an amino resin (C), and a quaternary ammonium base-containing modified epoxy resin (B) and amino It consists of a perfluoroalkyl group and a perfluoroalkenyl group with respect to a total solid content of 100 parts by mass of the resin (C). A precoat fin for a heat exchanger, wherein the resin (A) having at least one fluorine atom-containing group selected from the group is formed from a water-based water-repellent coating composition having a solid content of 1 to 30 parts by mass. It is a material.

  Further, the present invention provides a water repellent surface and a condensed water eliminating effect in which a large number of flat precoated fin materials are arranged in parallel with each other at a predetermined interval and have a frosting suppressing effect between adjacent precoated fin materials. A heat exchanger having a fin structure facing a hydrophilic surface having a plurality of pre-coated fin materials on one surface of a fin substrate formed of an aluminum plate made of aluminum or an aluminum alloy. It is composed of a number of single-sided water-repellent / single-sided hydrophilic fin materials having a cross-linked water-repellent film that forms a surface and a hydrophilic film that forms a hydrophilic surface on the other surface, or from aluminum or an aluminum alloy A plurality of double-sided water-repellent films having a cross-linked water-repellent film that forms a water-repellent surface on both sides of a fin substrate formed of an aluminum plate. And a plurality of double-sided hydrophilic fin materials having a hydrophilic film that forms hydrophilic surfaces on both sides of a fin substrate formed of an aluminum plate made of aluminum or an aluminum alloy, and the crosslinked water-repellent material Resin (A) whose film has at least one fluorine atom-containing group selected from the group consisting of perfluoroalkyl groups and perfluoroalkenyl groups, quaternary ammonium base-containing modified epoxy resin (B) and amino resin (C) At least one selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group with respect to a total of 100 parts by mass of the solid content of the quaternary ammonium base-containing modified epoxy resin (B) and amino resin (C) Aqueous water repellent coating composition in which the solid content of the resin (A) having a fluorine atom-containing group is 1 to 30 parts by mass It is a heat exchanger, characterized in that the al formed.

  In the present invention, the aluminum plate material forming the fin substrate may be made of pure aluminum or an aluminum alloy, and is not particularly limited. About a board | substrate, from a corrosion-resistant viewpoint, it is preferable that the corrosion-resistant film | membrane is provided in the both surfaces preferably.

  For this purpose, the corrosion-resistant film provided on both surfaces of the fin substrate is formed by applying a corrosion-resistant treatment agent on both surfaces of the fin substrate. Examples of the corrosion-resistant treatment agent used here include a chromate treatment agent. In addition, a phosphoric acid chromate treatment agent, a chromium-free chemical conversion treatment agent, an organic corrosion-resistant primer, and the like can be mentioned. From the viewpoint of an environmentally friendly corrosion-resistant film, a chromium-free chemical conversion treatment agent and an organic corrosion-resistant primer are preferable.

  In the present invention, as a precoat fin material for a heat exchanger, a cross-linked water-repellent film that forms a water-repellent surface is provided on one side of the fin substrate, and a hydrophilic film that forms a hydrophilic surface is provided on the other side. A single-sided water-repellent / single-sided hydrophilic fin material is formed, or a double-sided water-repellent fin material is formed by providing a cross-linked water-repellent film having a frosting-inhibiting effect on both sides of the fin substrate. The crosslinked water-repellent film having the effect of suppressing frost formation is a water-repellent water-repellent film containing a resin (A) having a fluorine atom-containing group, a quaternary ammonium base-containing modified epoxy resin (B), and an amino resin (C) described later. It is necessary that the water-repellent film formed from the coating composition forms a crosslinked structure.

  Here, about the crosslinked water-repellent film having the frosting-inhibiting effect, the water contact angle is preferably 100 ° or more, more preferably 105 ° or more, and the film thickness is usually 0.05 to 5. The thickness is 0 μm, preferably 0.1 to 4.0 μm, more preferably 0.2 to 2.0 μm. The higher the water contact angle of this crosslinked water-repellent film, the better. However, if the water contact angle of this crosslinked water-repellent film is lower than 100 °, there is a problem that the effect of suppressing frost formation is reduced. Regarding the film thickness of the crosslinked water-repellent film, if it is less than 0.05 μm, the frost formation between lots and hydrophilic variations increase, and the aging of frost formation and hydrophilic durability increases over time. On the other hand, if the thickness exceeds 5.0 μm, it is not only possible to expect further suppression of frost formation and improvement in hydrophilicity, but rather a heat-induced film when brazing a copper pipe for refrigerant to the fin material There is a problem that the burning of the film becomes conspicuous and the cost increases as the film thickness increases.

  In the present invention, the crosslinked water-repellent coating film that exhibits the above-described frosting-inhibiting effect is formed by applying an aqueous water-repellent coating composition, and as an aqueous water-repellent coating composition used for this purpose, Resin having at least one fluorine atom-containing group selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group (A), a quaternary ammonium base-containing modified epoxy resin, from the viewpoint of maintaining a frosting suppression effect for a long period of time An aqueous water-repellent coating composition containing (B) and an amino resin (C) can be mentioned. In the following description, “resin (A) having at least one fluorine atom-containing group selected from the group consisting of perfluoroalkyl groups and perfluoroalkenyl groups” is simply referred to as “resin having fluorine atom-containing group (A ) ".

<Resin having fluorine atom-containing group (A)>
In the water-based water-repellent coating composition, as the resin (A) having a fluorine atom-containing group, a known resin can be used as long as it has a perfluoroalkyl group and / or a perfluoroalkenyl group. What was disperse | distributed or melt | dissolved in the medium (henceforth an "aqueous medium") which has water as a main component can be used. The resin (A) having such a fluorine atom-containing group is, for example, at least one fluorine atom-containing group selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group having a structure represented by the following general formula (1). Polymerizable unsaturated monomer (a-1) [hereinafter, sometimes referred to as “polymerizable unsaturated monomer (a-1) having a fluorine atom-containing group]” and other polymerizable unsaturated monomers A resin obtained by copolymerizing a saturated monomer (a-2) is preferable. The method for carrying out the polymerization reaction can be selected from known polymerization methods, and examples thereof include bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, dispersion polymerization, and the like, which are dispersed or dissolved in an aqueous medium. From the viewpoint of resin production efficiency and the like, emulsion polymerization is preferred.

(In the formula, Rf represents a linear or branched perfluoroalkyl group or perfluoroalkenyl group having 1 to 21 carbon atoms. R represents a hydrogen atom, a halogen atom, or a methyl group. X represents an oxygen atom or Y represents an imino group, and Y represents a divalent organic group having 1 to 20 carbon atoms which may or may not contain an oxygen atom, a sulfur atom, a nitrogen atom or a phosphorus atom.

The fluorine atom-containing group is preferably a perfluoroalkyl group. Examples of the perfluoroalkyl group include —CF ₃ , —CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ , —CF (CF _{3) 2, -CF 2 CF 2} CF 2 CF 3, -CF 2 CF (CF 3) 2, -C (CF 3) 3, - (CF 2) 4 CF 3, - (CF 2) 2 CF (CF _{3) 2, -CF 2 C (} CF 3) 3, -CF (CF 3) CF 2 CF 2 CF 3, - (CF 2) 5 CF 3, - (CF 2) 3 CF (CF 3) 2, - (CF ₂ ) ₄ CF (CF ₃ ) ₂ ,-(CF ₂ ) ₇ CF ₃ ,-(CF ₂ ) ₅ CF (CF ₃ ) ₂ ,-(CF ₂ ) ₆ CF (CF ₃ ) ₂ ,-(CF _{2) 9} CF _3, and the like. The carbon number of the perfluoroalkyl group is 1 to 21, preferably 2 to 20, and more preferably 4 to 16.

  Emulsion polymerization of a polymerizable unsaturated monomer (a-1) having a fluorine atom-containing group is a mixture of the monomer (a-1) and another polymerizable unsaturated monomer (a-2). Can be carried out by a known method of emulsion polymerization in an aqueous medium using an emulsifier and a polymerization initiator. In the emulsion polymerization, a hydrophilic or hydrophobic organic solvent may be used as necessary.

  A conventionally well-known emulsifier can be used as an emulsifier, For example, anionic surfactant, a nonionic surfactant, an amphoteric surfactant, or what combined them is used. As the surfactant, a compound to which a fluorine atom such as a fluorinated alkyl group is bonded may be used as necessary.

  As the polymerization initiator, conventionally known polymerization initiators can be used, for example, persulfates such as ammonium persulfate (APS), potassium persulfate, sodium persulfate, diisopropyl peroxydicarbonate (IPP), Examples thereof include oil-soluble polymerization initiators such as benzoyl peroxide, dibutyl peroxide, and azobisisobutyronitrile (AIBN).

  In the emulsion polymerization reaction, a chain transfer agent may be used. Examples of the chain transfer agent include malonic acid diesters such as diethyl malonate (MDE) and dimethyl malonate, ethyl acetate, butyl acetate and the like. Examples thereof include acetates, alcohols such as methanol and ethanol, mercaptans such as n-lauryl mercaptan and n-octyl mercaptan, and α-methylstyrene dimer.

  By carrying out the polymerization reaction at a polymerization temperature of 20 to 150 ° C. and a polymerization time of 0.1 to 100 hours, an aqueous dispersion of the resin (A) having a fluorine atom-containing group can be produced. In the aqueous dispersion, the resin (A) having a fluorine atom-containing group is obtained as particles having an average particle diameter of 10 to 500 nm, preferably 30 to 200 nm. The solid content concentration is preferably about 5 to 50% by mass.

  The particles of the resin (A) having a fluorine atom-containing group may have a single-layer structure or a multilayer structure including a core-shell structure, and the inside of the particles may be cross-linked. Can be obtained by a known method.

  The other polymerizable unsaturated monomer (a-2) is not particularly limited as long as it has copolymerization reactivity with the polymerizable unsaturated monomer (a-1) having a fluorine atom-containing group. For example, acrylic acid, methacrylic acid, itaconic acid, itaconic anhydride, maleic anhydride, butadiene, isoprene, chloroprene, alkyl (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms, (Meth) acrylic acid cyclohexyl ester, (meth) acrylic acid isobornyl, (meth) acrylic acid benzyl ester, di (meth) acrylic acid polyethylene glycol; aromatic vinyl-based singles such as styrene, α-methylstyrene, p-methylstyrene 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate Hydroxyalkyl (meth) acrylates such as hydroxyamyl (meth) acrylate and hydroxyhexyl (meth) acrylate; vinyl alkyl ethers having 1 to 20 carbon atoms in the alkyl group; halogenated alkyl vinyl ethers having 1 to 20 carbon atoms in the alkyl group A vinyl alkyl ketone having an alkyl group having 1 to 20 carbon atoms; a silyl group-containing unsaturated monomer such as vinyltriethoxysilane or γ- (methacryloxypropyl) trimethoxysilane; (meth) acrylamide, N-methylol ( (Meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, Nn-propoxymethyl (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, N-sec-butoxymethyl (meth) acryl (Meth) acrylamide monomers such as amide and N-tert-butoxymethyl (meth) acrylamide; vinyl acetate, vinyl esters such as “Veova” (Shell's vinyl ester), acrylonitrile, methacrylonitrile ethylene, butadiene, etc. Can be mentioned. In the present specification, (meth) acrylic acid is a generic term for acrylic acid and methacrylic acid, (meth) acrylate is a generic term for acrylate and methacrylate, and (meth) acrylamide is a generic term for acrylamide and methacrylamide. .

  Commercially available products of the resin (A) having a fluorine atom-containing group dissolved or dispersed in an aqueous medium include Unidyne TG-652, Unidyne TG-664, Unidyne TG-410, Unidyne TG-5521, Unidyne TG-5601, Unidyne. TG-8711, Unidyne TG-470B, Unidyne TG-500S, Unidyne TG-580, Unidyne TG-581, Unidyne TG-658 (above, Daikin, trade name), SWK-601 (Seimi Chemical), FS6810 (Manufactured by Fluoro Technology), NK guard SR-108 (manufactured by Nikka Chemical Co., Ltd.) and the like.

  The resin (A) having a fluorine atom-containing group is produced by the above polymerizable unsaturated monomer (a-1) having a fluorine atom-containing group and other polymerizable unsaturated monomer (a-2). In addition to the copolymerization reaction method, a polymerization reaction of a polymerizable unsaturated monomer using a perfluoroalkyl group-containing radical generator as a polymerization initiator can be performed. Examples thereof include fluorine-containing organic peroxides described in JP-A No. 2010-195,937.

<Quaternary ammonium base-containing modified epoxy resin (B)>
The aqueous water-repellent coating composition contains a quaternary ammonium base-containing modified epoxy resin (B) described below from the viewpoint of processability, adhesion, moisture resistance, and corrosion resistance of the resulting coating film.

  The modified epoxy resin (B) can be produced by reacting a mixture containing an epoxy resin (b-1), a carboxyl group-containing acrylic resin (b-2) and an amine compound (b-3). In the reaction, a reaction for producing a quaternary ammonium base and an esterification reaction between an epoxy group contained in the epoxy resin and a carboxyl group contained in the carboxyl group-containing acrylic resin proceeded to modify the quaternary ammonium base-containing modification. An epoxy resin (B) is produced. In the reaction, the epoxy group of the epoxy resin (b-1) is opened to generate a hydroxyl group. And the hydroxyl group of the said quaternary ammonium base containing modified epoxy resin (B) produced | generated in this way has reactivity with the amino resin (C) mentioned later.

  The epoxy resin (b-1) is preferably a bisphenol type epoxy resin from the viewpoints of adhesion and corrosion resistance. The bisphenol type epoxy resin is a resin obtained by a reaction between a bisphenol compound and an epihalohydrin, for example, epichlorohydrin.

  Examples of the bisphenol compound include bis (4-hydroxyphenyl) -2,2-propane [bisphenol A], 4,4-dihydroxybenzophenone, bis (4-hydroxyphenyl) methane [bisphenol F], 4,4- Dihydroxydiphenyl sulfone [bisphenol S] and the like can be mentioned. Among the bisphenol type epoxy resins (b-1), it is preferable to use a bisphenol A type epoxy resin from the viewpoint of corrosion resistance.

  From the viewpoint of dispersion stability in an aqueous medium, processability and hygiene of the resulting coating film, the number average molecular weight of the bisphenol type epoxy resin (b-1) is preferably 4,000 to 30,000, preferably Those having an epoxy equivalent in the range of 5,000 to 30,000 and an epoxy equivalent in the range of 2,000 to 10,000, preferably 2,500 to 10,000 are preferably used.

  Here, examples of commercially available bisphenol A type epoxy resins that can be used as the bisphenol type epoxy resin (b-1) include jER1010, jER1256B40, and jER1256 manufactured by Japan Epoxy Resin Co., Ltd.

The bisphenol A type epoxy resin may be a bisphenol A type modified epoxy resin obtained by modifying a bisphenol A type epoxy resin with a dibasic acid. In this case, as the bisphenol A type epoxy resin to be reacted with the dibasic acid, those having a number average molecular weight of 2,000 to 8,000 and an epoxy equivalent in the range of 1,000 to 4,000 are suitable. Can be used for Examples of the dibasic acid include compounds represented by the general formula HOOC— (CH ₂ ) _n —COOH ( _{where n} represents an integer of 1 to 12), specifically succinic acid and adipic acid. Pimelic acid, azelaic acid, sebacic acid, dodecanedioic acid and the like, hexahydrophthalic acid and the like can be used, and adipic acid can be particularly preferably used.

  The modified bisphenol A type epoxy resin is prepared by reacting a mixture of the bisphenol A type epoxy resin and a dibasic acid in the presence of an esterification catalyst such as tri-n-butylamine or an organic solvent at a reaction temperature of 120 to 180 ° C. And a reaction time of about 1 to 4 hours.

  The carboxyl group-containing acrylic resin (b-2) used in the production of the modified quaternary ammonium base-containing modified epoxy resin (B) is composed of a carboxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers. It can manufacture by heating the mixture which contains it on the conditions of 80-150 degreeC and 1 to 10 hours in an organic solvent using a radical polymerization initiator, for example, and carrying out a copolymerization reaction.

  Examples of the other polymerizable unsaturated monomer that can be used for the production of the carboxyl group-containing acrylic resin (b-2) include, for example, the other polymerization described in the resin (A) having a fluorine atom-containing group. And unsaturated unsaturated monomer (a-2).

  As the radical polymerization initiator used in the production of the carboxyl group-containing acrylic resin (b-2), an organic peroxide type, an azo type, or the like is used. Examples of the organic peroxide type include benzoyl peroxide, t -Butylperoxy-2-ethylhexanoate, di-t-butylperoxide, t-butylperoxybenzoate, t-amylperoxy-2-ethylhexanoate, etc. Examples thereof include azobisisobutyronitrile and azobisdimethylvaleronitrile.

  In the copolymerization reaction in producing the carboxyl group-containing acrylic resin (b-2), a chain transfer agent may be used as necessary. Examples of the chain transfer agent include α-methylstyrene dimer and mercaptan compounds. And the like.

  The carboxyl group-containing acrylic resin (b-2) has a weight average molecular weight of 5,000 to 100,000, preferably 10 from the viewpoints of stability in an aqueous medium, processability of the resulting coating film, adhesion, and the like. The resin acid value is preferably in the range of 150 to 700 mgKOH / g and 200 to 500 mgKOH / g.

  The amine compound (b-3) is preferably a tertiary amine compound such as triethylamine, dimethylethanolamine, triethanolamine, monomethyldiethanolamine, N-methylmorpholine.

  The quaternary ammonium base-containing modified epoxy resin (B) is a mixture of the epoxy resin (b-1), carboxyl group-containing acrylic resin (b-2) and amine compound (b-3) in an organic solvent. It can manufacture by heating and making it react on conditions of -120 degreeC and 0.5 to 8 hours.

  Here, the blending ratio of the epoxy resin (b-1) and the carboxyl group-containing acrylic resin (b-2) in the above reaction may be appropriately selected according to coating workability and coating film performance, preferably The solid content mass ratio of resin (b-1) / resin (b-2) is preferably in the range of 10/90 to 95/5, more preferably 60/40 to 90/10.

  The amount of the amine compound (b-3) used is the total solid content of the epoxy resin (b-1) and the carboxyl group-containing acrylic resin (b-2) from the viewpoint of the moisture resistance and corrosion resistance of the obtained film. A range of 1-10% by weight based on the minutes is preferred.

  The quaternary ammonium base-containing modified epoxy resin (B) obtained by the above reaction has an acid value of 20 from the viewpoints of stability in an aqueous medium, processability of the resulting coating film, adhesion, moisture resistance, and corrosion resistance. ˜120 mg KOH / g, preferably 30 to 100 mg KOH / g, and the weight average molecular weight is 1,000 to 40,000, preferably 2,000 to 15,000.

  In this specification, “weight average molecular weight” is a value obtained by converting retention time (retention capacity) measured by gel permeation chromatography using polystyrene as a solvent, based on the weight average molecular weight of polystyrene. . The “number average molecular weight” is a value obtained by calculation from the weight average molecular weight.

  As the gel permeation chromatograph, “HLC8120GPC” (manufactured by Tosoh Corporation) was used. As the column, four columns of “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL”, “TSKgel G-2000HXL” (both manufactured by Tosoh Corporation, trade name) are used, Mobile phase: Tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 ml / min, detector: under the conditions of RI.

  The quaternary ammonium base-containing modified epoxy resin (B) is neutralized and dispersed in an aqueous medium, but as a neutralizing agent used for neutralization, basic compounds such as amines and ammonia are preferably used. Is done.

  Representative examples of amines used as the neutralizing agent include triethylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, morpholine, and the like. Of these, triethylamine and dimethylethanolamine are particularly preferred. The neutralization of the quaternary ammonium base-containing modified epoxy resin (B) is usually preferably in the range of 0.2 to 2.0 equivalent neutralization with respect to the carboxyl group in the resin.

In the present invention, from the viewpoint of adhesion, moisture resistance, corrosion resistance, etc., the amount of quaternary ammonium base formed during the esterification reaction and by neutralization (number of moles of quaternary ammonium base contained per 1 g of resin) is 3.0 × 10 ⁻⁴ mol / g or less, preferably 0.6 × 10 ^{−4 to} 3.0 × 10 ⁻⁴ mol / g, more preferably 0.8 × 10 ⁻⁴ to It is desirable to be within the range of 2.5 × 10 ⁻⁴ mol / g.

Here, the amount of the quaternary ammonium base is measured as follows. That is, the sample after the start of the reaction is dissolved in a solvent to prepare a sample solution, and the obtained sample solution is obtained by dissolving an indicator solution (an indicator having a sulfonic acid group and a hydroxyl group as functional groups in the solvent. The titration reaction is carried out by dropping the solution, and the indicator in the indicator solution reacts with the quaternary ammonium chloride epoxy compound in the sample solution to simultaneously ionize both the sulfonic acid group and the hydroxyl group. The first stage of the titration reaction in which an acid is formed, and the sulfonic acid group in which only the sulfonic acid group is ionized by the reaction of the ionization indicator generated in the first stage titration reaction with the indicator in the indicator solution. For the second stage of the titration reaction in which an ionization indicator is formed, plot the relationship between the titer and conductivity, and connect the plots in the first stage. Lines and determine the titer t ₁ in the first stage from the titer at an intersection between the straight line connecting the plots in the second stage, by the following equation (1), quaternary ammonium salts of the sample in terms of solid content in 1 g (mol / g).

Quaternary ammonium salt content (mol / g)
= T ₁ (ml) × 2 × indicator concentration (mol / l) × (1 / 1,000)
× {100 / (Sample (g) × Solid content (%))} ……………… Formula (1)
The aqueous medium in which the quaternary ammonium base-containing modified epoxy resin (B) is dispersed may be water alone or a mixture of water and an organic solvent. Any known organic solvent can be used as long as the stability of the quaternary ammonium base-containing modified epoxy resin (B) in an aqueous medium is not impaired.

<Amino resin (C)>
Examples of the amino resin (C) contained in the aqueous water-repellent coating composition include melamine resin, urea resin, and benzoguanamine resin, and melamine resin is preferable from the viewpoint of processability and adhesion.

  As the melamine resin, for example, a part or all of the methylol group of methylolated melamine is a monohydric alcohol having 1 to 8 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl. Examples include partially etherified or fully etherified melamine resins etherified with alcohol, i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

  These may be used in which all methylol groups are etherified or partially etherified, and methylol groups or imino groups remain. For example, alkyl etherified melamines such as methyl etherified melamine, ethyl etherified melamine, butyl etherified melamine and the like can be mentioned, and only one kind or two or more kinds may be used in combination. Among these, a methyl etherified melamine resin obtained by methyl etherifying at least a part of methylol groups is preferable.

  Examples of commercially available melamine resins that satisfy such conditions include “Cymel 202”, “Cymel 232”, “Cymel 235”, “Cymel 238”, “Cymel 254”, “Cymel 266”, and “Cymel 267”. , “Cymel 272”, “Cymel 285”, “Cymel 301”, “Cymel 303”, “Cymel 325”, “Cymel 327”, “Cymel 350”, “Cymel 370”, “Cymel 701”, “Cymel 703” , “Cymel 736”, “Cymel 738”, “Cymel 771”, “Cymel 1141”, “Cymel 1156”, “Cymel 1158”, “My Coat 212”, “My Coat 715”, “My Coat 776”, etc. (Nippon Cytec Co., Ltd.), “Uban 120”, “Uban 20HS”, “ Ban 2021 "," U-VAN 2028 "," U-VAN 2061 "and the like (or more, manufactured by Mitsui Chemicals Co., Ltd.) are commercially available under the trade name of, and" Melan 522 "and the like (manufactured by Hitachi Chemical Co., Ltd.).

  The blending ratio of the quaternary ammonium base-containing modified epoxy resin (B) and amino resin (C) is 95 / as the solid content mass ratio of the quaternary ammonium base-containing modified epoxy resin (B) / amino resin (C). A range of 5-50 / 50, particularly 93 / 7-60 / 40 is preferred. If the amount of the amino resin (C) is too small, sufficient curability cannot be obtained. On the other hand, if the amount is too large, the processability of the manufactured pre-coated fin material may be lowered.

  The content of the resin (A) having a fluorine atom-containing group in the water-based water-repellent coating composition is the above-mentioned quaternary ammonium base-containing modified epoxy in terms of solid content from the viewpoints of frost formation suppression, corrosion resistance, and coating stability. It is 1-30 mass parts with respect to a total of 100 mass parts of resin (B) and amino resin (C), Preferably it is 3-25 mass parts, More preferably, it is 10-22 mass parts.

  In addition to the resin having a fluorine atom-containing group (A), the quaternary ammonium base-containing modified epoxy resin (B) and the amino resin (C), the water-based water-repellent coating composition in the present invention, if necessary, Basic compound, crosslinking agent other than amino resin (C) (eg, blocked polyisocyanate), colloidal silica, antibacterial agent, coloring pigment, rust preventive pigment known per se (eg, chromate-based, lead-based, molybdenum) Acid), rust inhibitors (eg, phenolic carboxylic acids such as tannic acid and gallic acid and their salts, organic phosphoric acids such as phytic acid and phosphinic acid, metal salts of heavy phosphoric acid, nitrite, etc.) Agents and aqueous media can be added. Here, the aqueous medium may be water or a mixed solvent of water and a small amount of an organic solvent or a basic compound such as amines or ammonia. The content of is usually 80% by mass or more.

  In the present invention, the single-side water-repellent / single-side hydrophilic fin material is used to form a heat exchanger fin structure in which the water-repellent surface and the hydrophilic surface face each other, or the fin substrate Using a double-sided water-repellent fin material provided with a cross-linked water-repellent film that forms a water-repellent surface on both sides, and a double-sided hydrophilic fin material provided with a hydrophilic film that forms a hydrophilic surface on both sides of a fin substrate The fin structure of the heat exchanger in which the water-repellent surface and the hydrophilic surface face each other is configured. The hydrophilic film on the one-sided water-repellent / single-sided hydrophilic fin material and the two-sided hydrophilic fin material will be described later. It is formed by applying a hydrophilic paint.

  Here, about the hydrophilic membrane | film which exhibits the said condensed water exclusion effect, the water contact angle becomes like this. Preferably it is 40 degrees or less, More preferably, it is 30 degrees or less, Moreover, the film thickness is 0.05-5. It is 0 μm or less, preferably 0.1 to 4.0 μm, more preferably 0.2 to 2.0 μm. The lower the water contact angle of this hydrophilic film, the better. However, if the water contact angle of this hydrophilic film is higher than 40 °, there is a problem that condensed water does not flow easily. As in the case of the cross-linked water-repellent film, if the film thickness is less than 0.05 μm, frost suppression between lots and hydrophilic variation increase, and frost suppression and hydrophilic durability deteriorate over time. On the contrary, if it exceeds 5.0 μm, it is not only possible to expect further frosting suppression and hydrophilic improvement, but rather braze a copper pipe for refrigerant to the fin material There are problems such as the scorching of the film due to the heat at the time becomes conspicuous and the cost increases as the film thickness increases.

  In the present invention, examples of the hydrophilic paint used to form the hydrophilic film exhibiting the effect of eliminating condensed water include inorganic hydrophilic paints such as water glass, silica and boehmite, and water-soluble acrylic resins. Organic hydrophilic coatings containing water-soluble cellulose resin, water-soluble amino resin, polyvinyl alcohol, etc., organic-inorganic composite hydrophilic coatings containing inorganic materials and organic resins, etc. From the viewpoint of mold wear countermeasures, organic hydrophilic paints are preferred.

A well-known thing can be used as said organic hydrophilic coating material, For example, the following organic hydrophilic coating composition (E) can be mentioned.
(1) Polyvinyl alcohol having a saponification degree of 87% or more and at least a part of carboxyl groups of a high acid value acrylic resin having a resin acid value of 300 mgKOH / g or more have no boiling point of less than 180 ° C. and An organic hydrophilic coating composition containing a neutralized resin obtained by neutralizing with a basic compound that does not decompose at less than 180 ° C. to form a salt.
(2) An organic hydrophilic coating composition containing a polyvinyl alcohol resin and a polyethylene glycol resin as main components and containing a nitric acid compound having a monovalent or divalent element (see JP 2002-275,407) .

<Corrosion-resistant film, crosslinked water-repellent film, and method for forming hydrophilic film>
There is no particular limitation on the method of forming the corrosion-resistant film, the crosslinked water-repellent film, and the hydrophilic film on the surface of the fin substrate. For example, a roll coater method that uses a commonly used roll coater or a coating method Gravure roll method to apply using gravure roll convenient for volume control, natural coat method convenient for thick coating, reverse coat method, bar coat method, spray method, etc., which are advantageous for beautifully finishing the coated surface Can be adopted.

  For example, a cross-linked water-repellent coating is formed on one surface of the fin substrate using the water-based water-repellent coating composition, and a hydrophilic coating is formed on the other surface using the organic hydrophilic coating composition. Thus, when producing a single-sided water-repellent / single-sided hydrophilic fin material for a heat exchanger, first, the water-repellent coating composition is applied to one surface of the fin substrate using a roll coater or the like, Next, for example, heating is performed under high temperature ventilation with a floater oven or the like, preferably heating is performed at high temperature of 60 to 300 ° C. for 2 seconds to 30 minutes under high temperature ventilation of 10 to 30 m / min, and one surface of the fin substrate is formed. A crosslinked water-repellent film is formed, then a hydrophilic coating composition is applied to the other surface of the fin substrate, and then heated under high temperature ventilation, for example, by a floater oven, preferably at high temperature ventilation of 10 to 30 m / min. 60 ~ below Heating is performed at a high temperature of 300 ° C. for 2 seconds to 30 minutes. Alternatively, the water-based water-repellent coating composition is applied to one surface of the fin substrate using a roll coater or the like, then the hydrophilic coating composition is applied to the other surface of the fin substrate, and then heated at a high temperature using, for example, a floater oven. Heating under ventilation, preferably heating at a high temperature of 60 to 300 ° C. under high temperature ventilation of 10 to 30 m / min for 2 seconds to 30 minutes.

<Fin structure of heat exchanger>
The precoat fin material for a heat exchanger of the present invention obtained as described above is subjected to normal molding processing, for example, after applying volatile press oil for press molding processing to the surface of the precoat fin material, slit processing, etc. By performing the forming process, the heat exchange fin having a desired fin shape is formed and used.

The fin structure of the heat exchanger formed using the heat exchange fins described above is such that the water-repellent surface provided with the crosslinked water-repellent coating and the hydrophilic surface provided with the hydrophilic coating face each other. Configured.
For example, when the above single-sided water-repellent / single-sided hydrophilic fin material is used as the precoat fin material for a heat exchanger, a large number of single-sided water-repellent / single-sided hydrophilic fin materials have a relative relationship between the water-repellent surface and the hydrophilic surface. The fin structure may be configured by arranging it so as to face and fixing it to the tube material. Further, when the above double-sided water-repellent fin material is used as a precoat fin material for a heat exchanger, both sides of the double-sided water-repellent fin material and a hydrophilic film formed on both sides of the fin substrate using the above-mentioned hydrophilic paint. Using a hydrophilic fin material, these double-sided water-repellent fin material and double-sided hydrophilic fin material are alternately arranged so that the water-repellent surface and the hydrophilic surface face each other and fixed to the tube material, and the fin structure is What is necessary is just to comprise.

  According to the precoat fin material for a heat exchanger composed of the single-sided water-repellent / single-sided hydrophilic fin material of the present invention, the cross-linked water-repellent coating provided on one surface exhibits an excellent frosting-inhibiting effect, and the other Since the excellent condensate drainage effect is exhibited by the hydrophilic film provided on the surface, using this precoat fin material for heat exchangers, the fin structure of the heat exchanger excellent in frost suppression characteristics and condensate drainage characteristics Can be configured easily.

  Further, according to the heat exchanger having the fin structure of the present invention, the excellent frost formation suppressing effect due to the water repellent surface of the crosslinked water repellent coating and the excellent condensed water eliminating effect due to the hydrophilic surface of the hydrophilic coating are cooperating. In the heating operation, frost formation is prevented as much as possible, and under the condition where condensation is likely to occur on the fin surface, when water droplets generated by condensation on the water-repellent surface come into contact with the adjacent hydrophilic surface The water droplets can be easily transferred to the hydrophilic surface side and can be quickly removed, whereby a good heat exchange function can be maintained over a long period of time without increasing the ventilation resistance.

Hereinafter, preferred embodiments of the present invention will be described in detail based on examples and comparative examples.
In the following Examples and Comparative Examples, the measurement of the water contact angle of the crosslinked water-repellent coating and the hydrophilic coating and the confirmation of the frosting suppression effect were performed by the following methods.

(Measurement of water contact angle)
A part of the precoat fin material for heat exchangers prepared in each example and comparative example was cut into a size of 7 cm × 15 cm, and 2 μL of pure water was dropped on the film of a horizontally installed test piece, and a contact angle meter (Kyowa) The contact angle of water droplets formed on the film of the test piece was measured using Interface Science Co., Ltd. (CA-A).

[Confirmation test for frost suppression and condensed water elimination effect]
2 rows x 12 rows of color parts are pressed into the single-sided water-repellent / single-sided hydrophilic fin material (JIS A 1050, 500 mm x 25 mm x 0.1 mm) obtained in each of Examples 1-8 and Comparative Examples 1-8. A heat exchange fin, and a fin structure is formed so that the collar portion coincides and the water repellent surface and the hydrophilic surface face each other at an interval of 1.5 mm. Laminate and insert a copper tube (JIS-C1220, outer diameter 7mm, wall thickness 0.3mm) into the collar of this laminate, then expand the copper tube with a mandrel and mechanically join the collar Examples 1 to 8 each having a fin structure in which a cross fin tube type heat exchanger (outside dimensions 500 mm × 25 mm × 250 mm) is manufactured and the water-repellent surface and the hydrophilic surface face each other at intervals of 1.5 mm And the heat exchanger for a cross fin and tube type test of Comparative Examples 1-8 was produced.

  Further, the fin material of Comparative Example 9 was pressed in the same manner as described above to form heat exchange fins, and the heat exchange fins were laminated at intervals of 1.5 mm so that the collar portions coincided with each other. Insert a copper tube (JIS-C1220, outer diameter 7mm, wall thickness 0.3mm) into the collar, then expand the copper tube with a mandrel and mechanically join the collar to test the cross fin tube type A heat exchanger (outside dimensions 500 mm × 25 mm × 250 mm) was prepared.

  Furthermore, using the double-sided water-repellent fin material and double-sided hydrophilic fin material (JIS A 1050, 500 mm × 25 mm × 0.1 mm) obtained in each of Examples 9 to 11, the water-repellent surface and the hydrophilic surface Have a fin structure in which the water-repellent surface and the hydrophilic surface face each other at an interval of 1.5 mm in the same manner as described above. The cross fin and tube type test heat exchangers of Examples 9 to 11 were produced.

  In Comparative Example 10, two double-sided water-repellent fin materials (JIS A 1050, 500 mm × 25 mm × 0.1 mm) of Example 9 were laminated, and then two double-sided hydrophilic fin materials (JIS A 1050, 500 mm × 25 mm × 0.1 mm) is repeated a plurality of times to form a fin structure, and the water repellent surface and water repellent surface, the water repellent surface and hydrophilic surface, and the hydrophilic surface and hydrophilic surface are 1. A cross fin and tube type test heat exchanger of Comparative Example 10 laminated so as to be formed at equal intervals of 5 mm was produced. Furthermore, in Comparative Example 11, five double-sided water-repellent fin materials (JIS A 1050, 500 mm × 25 mm × 0.1 mm) of Example 10 were laminated, and then five double-sided hydrophilic fin materials (JIS A 1050, 500 mm × 25 mm × 0.1 mm) is repeated a plurality of times to form a fin structure, and the water repellent surface and water repellent surface, the water repellent surface and hydrophilic surface, and the hydrophilic surface and hydrophilic surface are 1. A cross fin and tube type test heat exchanger of Comparative Example 11 laminated so as to be formed at equal intervals of 5 mm was produced.

  Next, a 50 wt% -propylene glycol aqueous solution was introduced as a refrigerant into the test heat exchangers of Examples 1 to 11 and Comparative Examples 1 to 11 prepared in this way, and the room temperature was 2 ° C and the humidity was RH 90% or more. In a thermostatic chamber, the refrigerant was circulated under conditions of a refrigerant temperature of −6 ° C. and a refrigerant flow rate of 1 L / min, and operated for 45 minutes to observe the frost formation state on the heat exchange fins of each test heat exchanger. Moreover, after defrosting, the defrosting operation for 3 minutes was performed with the 30 degreeC refrigerant | coolant, and the formation presence or absence of the bridge | bridging by the molten water (or condensed water) which generate | occur | produced between the heat exchange fins was observed.

  The frosting suppression effect is measured by measuring the time until the entire surface is frosted. X: When it is less than 15 minutes, Δ: When it is 15 minutes or more and less than 30 minutes, ○: When it is 30 minutes or more and less than 45 minutes, and A: Evaluated based on the standard when no frost is formed even after 45 minutes, and the condensed water removal effect is observed by observing the adhesion of molten water (or condensed water) between the fins after the defrosting operation. : Evaluation was made on the basis of a case where bridges occurred on almost the entire surface, Δ: A case where some bridges occurred, and ○: A case where no bridges were observed.

<Production of fin substrates A and B>
A 100 μm thick aluminum material (JIS A 1050) is used as the aluminum fin material. After the degreasing treatment, a chromate treatment agent (treatment agent I: manufactured by Nihon Parkerizing Co., Ltd. 712 "), or an organic processing agent (Treatment agent: manufactured by Kansai Paint Co., Ltd., trade name" Cosmer 9105 ") is applied with a roll coater to form a corrosion-resistant film, and used in the following examples and comparative examples. Substrates A and B were produced.

Here, when preparing the fin substrate (a) using the treatment agent (a), the treatment agent (a) is applied to both surfaces of the aluminum material using a roll coater so that the Cr amount is 20 mg / m ^2, and then PMT (Peak Metal Temperature) It is formed by drying at a temperature of 230 ° C. for 15 seconds, and when a treatment agent is used, the treatment agent is made to have a film thickness of 1.0 g / m ^{2 on} both sides of the aluminum plate. It was formed by coating with a roll coater and then drying at a temperature of PMT of 250 ° C. for 10 seconds.

<Example of production of water-based water-repellent coating composition>
In the following production examples, “parts” represents mass parts, and “%” represents mass%.
(1) Manufacture of carboxyl group-containing acrylic resin (ca) used for manufacture of ammonium base-containing modified epoxy resin (B) [Production Example 1: Solution of carboxyl group-containing acrylic resin (ca-1)]
850 parts of n-butanol was heated to 100 ° C. under a nitrogen stream, and a monomer mixture and a polymerization initiator “450 parts of methacrylic acid, 450 parts of styrene, 100 parts of ethyl acrylate, t-butylperoxy-2- 40 parts of ethylhexanoate "was added dropwise over 3 hours, and the mixture was aged for 1 hour after the addition. Subsequently, a mixed solution of 10 parts of t-butylperoxy-2-ethylhexanoate and 100 parts of n-butanol was added dropwise over 30 minutes, and then aged for 2 hours. Subsequently, 933 parts of n-butanol and 400 parts of ethylene glycol monobutyl ether were added to obtain a solution of a carboxyl group-containing acrylic resin (ca-1) having a solid content of about 30%. The obtained resin had a resin acid value of 300 mg KOH / g and a weight average molecular weight of about 17,000.

[Production Example 2: Solution of carboxyl group-containing acrylic resin (ca-2)]
1,400 parts of n-butanol were heated to 100 ° C. under a nitrogen stream, and the monomer mixture and the polymerization initiator “methacrylic acid 670 parts, styrene 250 parts, ethyl acrylate 80 parts, t-butylperoxy- "50 parts of 2-ethylhexanoate" was added dropwise over 3 hours, and the mixture was aged for 1 hour after the addition. Subsequently, a mixed solution of 10 parts of t-butylperoxy-2-ethylhexanoate and 100 parts of n-butanol was added dropwise over 30 minutes, and then aged for 2 hours. Subsequently, 373 parts of n-butanol and 400 parts of ethylene glycol monobutyl ether were added to obtain a solution of a carboxyl group-containing acrylic resin (ca-2) having a solid content of about 30%. The obtained resin had a resin acid value of 450 mg KOH / g and a weight average molecular weight of about 14,000.

(2) Production of ammonium base-containing modified epoxy resin (ae) [Production Example 3: Aqueous dispersion of ammonium base-containing modified epoxy resin (ae-1)]
jER828EL [manufactured by Japan Epoxy Resin Co., Ltd., epoxy resin, epoxy equivalent of about 190, number average molecular weight of about 380] 513 parts, bisphenol A 287 parts, tetramethylammonium chloride 0.3 parts and methyl isobutyl ketone 89 parts, nitrogen stream The reaction was carried out for about 4 hours while heating to 140 ° C. to obtain an epoxy resin solution. The resulting epoxy resin had an epoxy equivalent of 3,700 and a number average molecular weight of about 1,7000.

Next, 667 parts of a solution of the carboxyl group-containing acrylic resin (ca-1) having a solid content of about 30% obtained in Production Example 1 was added to the obtained epoxy resin solution and heated to 90 ° C. to uniformly dissolve the solution. Then, 40 parts of deionized water was added dropwise at the same temperature over 30 minutes, and then 30 parts of dimethylethanolamine was added and stirred for 1 hour to carry out the reaction. Further, 2380 parts of deionized water was added over 1 hour to obtain an aqueous dispersion of an ammonium base-containing modified epoxy resin (ae-1) having a solid content of about 25%. The obtained resin has a resin acid value of 48 mg KOH / g, a quaternary ammonium salt amount (according to the conductivity titration method in the specification) 1.2 × 10 ⁻⁴ mol / g, and a weight average molecular weight of 26,000. It was.

[Production Example 4: Aqueous dispersion of ammonium base-containing modified epoxy resin (ae-2)]
jER828EL [manufactured by Japan Epoxy Resin Co., Ltd., epoxy resin, epoxy equivalent of about 190, number average molecular weight of about 380] 519 parts, bisphenol A 281 parts, tetramethylammonium chloride 0.3 parts and methyl isobutyl ketone 89 parts, nitrogen stream The reaction was carried out for about 4 hours while heating to 140 ° C. to obtain an epoxy resin solution. The resulting epoxy resin had an epoxy equivalent of 2,800 and a number average molecular weight of about 12,000.

Next, 667 parts of a solution of the carboxyl group-containing acrylic resin (ca-2) having a solid content of about 30% obtained in Production Example 2 was added to the obtained epoxy resin solution and heated to 90 ° C. to uniformly dissolve the solution. At the same temperature, 40 parts of deionized water was added dropwise over 30 minutes, and then 53 parts of dimethylethanolamine was added and stirred for 1 hour to carry out the reaction. Further, 2,350 parts of deionized water was added over 1 hour to obtain an aqueous dispersion of an ammonium base-containing modified epoxy resin (ae-2) having a solid content of about 25%. The obtained resin had a resin acid value of 75 mg KOH / g, a quaternary ammonium salt amount (result of conductivity titration) of 1.8 × 10 ⁻⁴ mol / g, and a weight average molecular weight of 18,000.

(3) Production of water-based water-repellent coating composition (D) [Production Example 5: Water-based water-repellent coating composition (D-1)]
Unidyne TG-500S (* 2 of Note 2) 10 parts (solid content), 90 parts (solid content) of the quaternary ammonium base-containing modified epoxy resin (ae-1) obtained in Production Example 3, Mycoat 715 ( * 4) of Note 2 was added in 10 parts (solid content), and deionized water was further added to adjust the solid content to obtain an aqueous water-repellent coating composition (D-1) having a solid content of 10%.

[Production Examples 6 to 12: Water-based water-repellent coating composition (D-2) to (D-8)]
Each component is thoroughly mixed with a stirrer according to the formulation shown in Table 1 and Table 2 below, and deionized water is added to adjust the solid content to obtain a water-based water-repellent coating composition (D-2) to (D-2) to ( D-8) was created.

<Production example of hydrophilic coating composition (E)>
[Production Example 13: Polyvinyl alcohol aqueous solution (e-1)]
Denkapoval K-05 (manufactured by Denki Kagaku Kogyo Co., Ltd., saponification degree 99%, polymerization degree 550) was dissolved in water to obtain a polyvinyl alcohol aqueous solution (e-1) having a solid content of 14%.

[Production Example 14: Acrylic resin aqueous solution]
80 parts of “Julimer AC10LP” (manufactured by Nippon Pure Chemical Co., Ltd., polyacrylic acid, weight average molecular weight 25,000, acid value 779 mg KOH / g) is dissolved in 535 parts of a 3% -n-butanol aqueous solution, and an acrylic having a solid content of 13% An aqueous resin solution (e-2) was obtained.

[Production Example 15: Acrylic resin aqueous solution]
80 parts of “Julimer AC10LHP” (manufactured by Nippon Pure Chemicals Co., Ltd., polyacrylic acid, weight average molecular weight 250,000, acid value 779 mg KOH / g) is dissolved in 920 parts of a 3% -n-butanol aqueous solution, and an acrylic having a solid content of 8% An aqueous resin solution (e-3) was obtained.

[Production Example 16: hydrophilic coating composition (E-2)]
To 357 parts of the 14% solid polyvinyl alcohol aqueous solution (e-1) obtained in Production Example 13, 385 parts of the 13% solid acrylic resin aqueous solution (e-2) obtained in Production Example 14 was added. A mixed solution of 14.6 parts of lithium hydroxide monohydrate (LiOH.H ₂ O) and 131.4 parts of 3% -n-butanol aqueous solution so that the neutralization degree of the carboxyl group is 0.6 equivalent (Solution having a 10% lithium hydroxide monohydrate concentration) 146 parts were added and mixed and stirred, and 112 parts of 3% -n-butanol aqueous solution was added and mixed and stirred to obtain a solid content of 10 parts. % Hydrophilic coating composition (E-2) was obtained. Table 2 shows the paint formulation.

[Production Example 17: hydrophilic coating composition (E-3)]
To 357 parts of the polyvinyl alcohol aqueous solution (e-1) having a solid content of 14% obtained in Production Example 13, 385 parts of the aqueous acrylic resin solution (e-3) having a solid content of 13% obtained in Production Example 15 was added. A mixed solution of 14.6 parts of lithium hydroxide monohydrate (LiOH.H ₂ O) and 131.4 parts of a 3% n-butanol aqueous solution so that the neutralization degree of the carboxyl group is 0.6 equivalent ( 146 parts of a lithium hydroxide monohydrate concentration of 10%) was added and mixed and stirred, and 112 parts of 3% n-butanol aqueous solution was added and mixed and stirred to obtain a solid content of 10%. A hydrophilic coating composition (E-3) was obtained. Table 2 shows the paint formulation.

<Preparation of comparative water-repellent coating composition>
[Comparative Production Example 1: Modified epoxy resin containing no quaternary ammonium base]
jER828EL [manufactured by Japan Epoxy Resin Co., Ltd., epoxy resin, epoxy equivalent of about 190, number average molecular weight of about 380] 513 parts, bisphenol A 287 parts, tetramethylammonium chloride 0.3 parts, and methyl isobutyl ketone 89 parts, nitrogen The reaction was carried out for about 4 hours while heating to 140 ° C. under an air stream to obtain an epoxy resin solution. The obtained epoxy resin had an epoxy equivalent of 3,700 and a number average molecular weight of about 1,7000.

  Next, the epoxy resin solution thus obtained was charged with 667 parts of a carboxyl group-containing acrylic resin (ca-1) having a solid content of about 30% obtained in Production Example 1, and heated to 90 ° C. After uniformly dissolving, 40 parts of deionized water was added dropwise at the same temperature over 30 minutes, then 0.2 part of tetramethylammonium chloride was added, and the reaction was carried out with stirring for 3 hours. Further, a mixture of 2380 parts of deionized water and 23 parts of 25% -ammonia water was added over 1 hour to obtain an aqueous dispersion of a modified epoxy resin containing no quaternary ammonium base having a solid content of about 25%. It was. The obtained resin had a resin acid value of 48 mg KOH / g and a weight average molecular weight of 24,000.

<Example of production of single-sided water-repellent / single-sided hydrophilic fin material>
[Example 1]
Using the above-mentioned fin substrate A as the fin substrate, a coating D-1 of the water-repellent water-repellent coating composition shown in Table 1 is applied on the corrosion-resistant film on one surface of the fin substrate A by a roll coater (or bar coater). The film was coated at the film thickness shown in Table 4, and then dried at a temperature of PMT of 220 ° C. for 10 seconds to form a crosslinked water-repellent film.

  Next, a carboxymethylcellulose-based paint E-1 (trade name “Surfal Coat 160, manufactured by Nippon Paint Co., Ltd.) was applied on the corrosion-resistant film on the other side of the fin substrate a having a crosslinked water-repellent film on one side by a roll coater. )) Was applied at a film thickness shown in Table 4, and then dried at a temperature of PMT of 200 ° C. for 10 seconds to form a hydrophilic film, whereby a single-sided water-repellent / single-sided hydrophilic fin material according to Example 1 was prepared.

[Examples 2 to 8]
Using the fin substrate shown in Table 4, the water-repellent water-repellent paint composition shown in Table 4 and the paint E-1 as the hydrophilic paint composition, or the paint E-2 or paint E-3 shown in Table 2 are used. In the same manner as in Example 1 and when paint E-2 and paint E-3 were used, the single-sided water-repellent / single-sided hydrophilic fin material according to Examples 2 to 8 under the conditions of PMT 230 ° C. and 10 seconds, respectively. Was prepared.

(Comparative Example 1)
Using the above-mentioned fin substrate A as the fin substrate, the coating D-1 of the water-repellent water-repellent coating composition shown in Table 1 is formed on the corrosion-resistant film provided on both surfaces of the fin substrate A by the film shown in Table 4. The double-sided water-repellent fin material of Comparative Example 1 having a crosslinked water-repellent film on both sides of the fin substrate A was formed by coating with a thickness and then drying at a temperature of PMT 220 ° C. for 10 seconds.

[Comparative Example 2]
The above-mentioned fin substrate A is used as the fin substrate, and the coating E-2 of the hydrophilic coating composition shown in Table 1 is applied to the film thickness shown in Table 4 by a roll coater on the corrosion-resistant film provided on both surfaces of the fin substrate A. It was applied and then dried at a temperature of PMT of 230 ° C. for 10 seconds to form a double-sided hydrophilic fin material of Comparative Example 2 having a hydrophilic film on both sides of the fin substrate.

[Comparative Example 3]
The above-mentioned fin substrate A is used as the fin substrate, and the coating F-1 of the comparative water-repellent coating composition shown in Table 3 is formed on the corrosion-resistant film on one surface of the fin substrate A by the roll coater as shown in Table 4. And then dried at a temperature of PMT of 220 ° C. for 10 seconds to form a water repellent film.

  Next, the coating material E-1 of the hydrophilic coating composition was applied with a film thickness shown in Table 4 on the other surface of the fin substrate A provided with a water-repellent coating on one side by a roll coater. A hydrophilic film was formed by drying at a temperature of PMT of 200 ° C. for 10 seconds to prepare a single-sided water-repellent / single-sided hydrophilic fin material according to Comparative Example 3.

[Comparative Example 4]
The above-mentioned fin substrate A is used as the fin substrate, and the coating D-2 of the water-repellent water-repellent coating composition shown in Table 1 is formed on the corrosion-resistant film on one surface of the fin substrate A by the roll coater as shown in Table 4. And then dried at a temperature of PMT of 220 ° C. for 10 seconds to form a crosslinked water-repellent film.

  Next, the coating E-2 of the hydrophilic coating composition was applied at a film thickness shown in Table 4 by a roll coater on the corrosion-resistant coating on the other side of the fin substrate a provided with a crosslinked water-repellent coating on one side. Next, the film was dried at a temperature of PMT of 270 ° C. for 10 seconds to form a hydrophilic film, and a single-sided water-repellent / single-sided hydrophilic fin material according to Comparative Example 4 was prepared.

[Comparative Example 5]
The above-mentioned fin substrate A is used as the fin substrate, and the coating F-2 of the comparative water-repellent coating composition shown in Table 3 is formed on the corrosion-resistant film on one surface of the fin substrate A by the roll coater as shown in Table 4. And then dried at a temperature of PMT of 220 ° C. for 10 seconds to form a water repellent film.

  Next, the coating material E-1 of the hydrophilic coating composition was applied with a film thickness shown in Table 4 on the other surface of the fin substrate A provided with a water-repellent coating on one side by a roll coater. A hydrophilic film was formed by drying at a temperature of PMT of 270 ° C. for 10 seconds to prepare a single-sided water-repellent / single-sided hydrophilic fin material according to Comparative Example 4.

[Comparative Examples 6-9]
The above-mentioned fin substrate B is used as the fin substrate, and the comparative water-repellent coating compositions F3, F4, and F5 shown in Table 3 are formed on the corrosion-resistant film provided on both surfaces of the fin substrate B by a roll coater. The double-sided water-repellent fin material of Comparative Examples 6 to 8 having a comparative water-repellent film on both sides of the fin substrate was formed by coating with a thickness and then drying at a temperature of PMT of 220 ° C. for 10 seconds.
In Comparative Example 9, the fin substrate B was used as the fin substrate, and a fin material that did not form a water-repellent or hydrophilic film was prepared.

About the single-sided water-repellent / single-sided hydrophilic fin materials of Examples 1-8 and Comparative Examples 1-9 produced as described above, the crosslinked water-repellent coatings of Examples 1-8 and Comparative Examples 1-9 Measurement of the water contact angle on the water-repellent surface formed by the water-repellent film and the hydrophilic surfaces formed by the hydrophilic films of Examples 1 to 8 and Comparative Examples 1 to 9, and Examples 1 to 8 and About Comparative Examples 1-9, the heat exchanger was produced and the confirmation test of frost formation suppression and a condensed water exclusion effect was implemented.
The results are shown in Table 4.

  In Examples 1 to 8, the heat exchange fins used were frosted on the hydrophilic surface on which the hydrophilic film was formed, but did not grow until the frost was blocked. On the water-repellent surface on which the other crosslinked water-repellent film was formed, no frosting phenomenon occurred, and the entire surface did not frost within 30 minutes. After defrosting operation, the frost melting water adhering to the hydrophilic surface flows down, and the condensed water on the water-repellent surface flows down by touching the hydrophilic surface, there is no bridge formation, and the ventilation state is good. . At that time, the frost adhered to the hydrophilic surface also melted and flowed down.

  On the other hand, in Comparative Example 1, since both surfaces of the heat exchange fin were only a water-repellent film having a frost-inhibiting effect, no frosting phenomenon occurred, but after defrosting operation, the bridge was formed by dew condensation water. Formed. Moreover, in Comparative Example 2, since both surfaces of the heat exchange fin were only hydrophilic films, the entire surface was frosted and blocked in a short time. Furthermore, in Comparative Examples 3, 5, 6, and 8, because of the water-repellent coating that has no effect of suppressing frost formation, the entire surface is frosted in 15 to 30 minutes, and a bridge is formed by dew condensation water after defrosting operation. did. In Comparative Example 4, since one side was a water-repellent film having a frost-inhibiting effect, frost was not formed within 30 minutes, but after defrosting operation, the frost melting water adhering to the hydrophilic surface was The condensed water on the water-repellent surface did not flow down but touched the hydrophilic surface, but did not flow down, and a bridge was formed by the condensed water. Furthermore, in Comparative Example 7, because of the water-repellent film having a low frost suppression effect, the entire surface was frosted within 15 minutes, and after defrosting operation, a bridge was formed with condensed water. Furthermore, in the case of Comparative Example 9 using untreated heat exchange fins, as in Comparative Example 7, the entire surface was frosted within 15 minutes, and after defrosting operation, a bridge was formed with condensed water.

<Production example of double-sided water-repellent fin material>
Example 9
Using the above-mentioned fin substrate A or B as the fin substrate, the paint D-2 of the water-repellent water-repellent coating composition shown in Table 1 is displayed on the corrosion-resistant film provided on both surfaces of the fin substrate A or B by a roll coater. 5 and then dried at a temperature of 220 ° C. for 10 seconds to form a double-sided water-repellent fin material of Example 9 having a crosslinked water-repellent film on both sides of the fin substrate A.

Example 10
The above-mentioned fin substrate B is used as the fin substrate, and the coating D-3 of the water-repellent water-repellent coating composition shown in Table 1 is applied to the film shown in Table 5 by a roll coater on the corrosion-resistant film provided on both surfaces of the fin substrate B. The double-sided water-repellent fin material of Example 10 having a cross-linked water-repellent coating on both sides of the fin substrate was formed by coating with a thickness and then drying at a temperature of PMT 220 ° C. for 10 seconds.

Example 11
The above-mentioned fin substrate B is used as the fin substrate, and the coating D-4 of the water-repellent water-repellent coating composition shown in Table 1 is applied to the film shown in Table 5 by a roll coater on the corrosion-resistant film provided on both surfaces of the fin substrate B. The double-sided water-repellent fin material of Example 11 having a cross-linked water-repellent film on both sides of the fin substrate was formed by coating with a thickness and then drying at a temperature of PMT 220 ° C. for 10 seconds.

  About the obtained double-sided water-repellent fin material of each of Examples 9 to 11, the water contact angle was measured in the same manner as described above. The results are shown in Table 5.

<Example of manufacturing double-sided hydrophilic fin material>
The above-described fin substrate A or B is used as the fin substrate, and the coating E of the hydrophilic coating composition shown in Table 2 is provided on the corrosion-resistant film provided on both surfaces of the fin substrate A or B by a roll coater (or bar coater). -1, E-2 and E-3 were applied at the film thicknesses shown in Table 6, and then for E-1, 10 seconds at a temperature of PMT of 200 ° C, and for E-2 and E-3, a temperature of 230 ° C for PMT And dried for 10 seconds to form three types of double-sided hydrophilic fin materials (ac) having hydrophilic coatings on both sides of the fin substrate A or B.

  About each obtained double-sided hydrophilic fin material (ac), the water contact angle was measured in the same manner as described above. The results are shown in Table 6.

<Fin structure creation and frost control / condensate rejection test>
[Examples 9 to 11 and Comparative Examples 10 to 11]
Using the double-sided water-repellent fin materials of Examples 9 to 11 shown in Table 5 and the double-sided hydrophilic fin materials a to c shown in Table 6 prepared as described above, these double-sided water-repellent fin materials and double-sided hydrophilic materials. In the case of Examples 1 to 8, the fin structures of Examples 9 to 11 are configured by alternately arranging the conductive fin material so that the water-repellent surface and the hydrophilic surface face each other at an interval of 1.5 mm. A cross-fin tube type heat exchanger for testing was prepared in the same manner as above, and a confirmation test of the effect of suppressing frost formation and eliminating condensed water was conducted.

Further, in Comparative Example 10, a structure in which two double-sided water-repellent fin materials of Example 9 are laminated and then two double-sided hydrophilic fins a are laminated is repeated a plurality of times to form a fin structure. In Comparative Example 11, the structure in which five double-sided water-repellent fin materials D-3 of Example 10 were laminated and then five double-sided hydrophilic fins b were laminated was repeated a plurality of times to form a fin structure. In the same manner as described above, a cross-fin tube type heat exchanger for testing was produced, and a confirmation test of the effect of suppressing frost formation and eliminating condensed water was performed.
Table 7 shows the results of Examples 9 to 11 and Comparative Examples 10 to 11.

Claims (9)

Fin substrate made of aluminum plate made of aluminum or aluminum alloy, cross-linked water-repellent film having frost formation suppressing effect provided on one surface of this fin substrate, and condensation provided on the other surface of the fin substrate A precoat fin material for a heat exchanger provided with a hydrophilic film having a water exclusion effect,
The crosslinked water-repellent coating is a resin (A) having at least one fluorine atom-containing group selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group, a quaternary ammonium base-containing modified epoxy resin (B), and amino The resin (C) is contained and selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group with respect to a total solid content of 100 parts by mass of the quaternary ammonium base-containing modified epoxy resin (B) and amino resin (C). A precoat fin material for a heat exchanger, wherein the resin (A) having at least one fluorine atom-containing group is formed from an aqueous water-repellent coating composition having a solid content of 1 to 30 parts by mass.   The pre-coated fin material for a heat exchanger according to claim 1, wherein the crosslinked water-repellent coating is formed on any one of the corrosion-resistant coatings provided on both surfaces of the fin substrate.   The pre-coated fin material for a heat exchanger according to claim 1 or 2, wherein the crosslinked water-repellent coating has a water contact angle of 100 ° or more.   The precoat fin material for a heat exchanger according to any one of claims 1 to 3, wherein the hydrophilic film has a water contact angle of 40 ° or less.   The heat exchange according to any one of claims 1 to 4, wherein the crosslinked water-repellent coating is formed by baking after applying the water-based water-repellent coating composition, and has a film thickness of 0.05 to 5.0 µm. Pre-coated fin material for dexterity.   The precoat fin material for a heat exchanger according to any one of claims 1 to 4, wherein the hydrophilic film is formed by baking after applying a hydrophilic paint, and the film thickness is 0.05 to 5.0 µm. A plurality of plate-like pre-coated fin materials are arranged in parallel with each other at a predetermined interval, and a water-repellent surface having a frosting suppressing effect and a hydrophilic surface having a condensed water eliminating effect between adjacent pre-coated fin materials. Is a heat exchanger with a fin structure facing each other,
The plurality of pre-coated fin materials have a crosslinked water-repellent film that forms a water-repellent surface on one surface of a fin substrate formed of an aluminum plate made of aluminum or an aluminum alloy, and also forms a hydrophilic surface on the other surface. Cross-linked water repellency that is composed of a number of single-sided water-repellent / single-sided hydrophilic fin materials having a hydrophilic film or that forms a water-repellent surface on both sides of a fin substrate made of an aluminum plate made of aluminum or aluminum alloy Consists of a plurality of double-sided water-repellent fin materials having a film and a plurality of double-sided hydrophilic fin materials having a hydrophilic film that forms a hydrophilic surface on both surfaces of a fin substrate formed of an aluminum plate made of aluminum or an aluminum alloy Has been
The crosslinked water-repellent coating is composed of a resin (A) having at least one fluorine atom-containing group selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group, a quaternary ammonium base-containing modified epoxy resin (B), and an amino acid. The resin (C) is contained and selected from the group consisting of a perfluoroalkyl group and a perfluoroalkenyl group with respect to a total solid content of 100 parts by mass of the quaternary ammonium base-containing modified epoxy resin (B) and amino resin (C). A heat exchanger, wherein the resin (A) having at least one fluorine atom-containing group is formed from a water-based water-repellent coating composition having a solid content of 1 to 30 parts by mass.   The heat exchanger according to claim 7, wherein the plurality of pre-coated fin materials are formed of a plurality of single-side water-repellent / single-side hydrophilic fin materials.   The heat exchanger according to claim 7, wherein the plurality of pre-coated fin materials are composed of a plurality of double-sided water-repellent fin materials and a plurality of double-sided hydrophilic fin materials.