JP2000329497A - Fin for heat exchanger in car air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fins for a heat exchanger in a car air conditioner excellent in hydrophilicity and corrosion resistance. SOLUTION: The fins for heat exchanger is coated, on the surface thereof, with an antibacterial resin and an antibacterial composition containing microparticles. The antibacterial composition has a fungi resistance index of 2 or above estimated in the form of film according to JIS Z 2911 6.2.2, a contact angle with water of 25 deg. or above. After the film is immersed into water of 40 deg.C for 120 hours, the fungi resistance index is 2 or above and the contact angle with water is 25 deg. or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to antibacterial and antifungal properties,
The present invention relates to a fin for an air conditioner heat exchanger having excellent hydrophilicity and durability.

[0002]

2. Description of the Related Art Generally, in a heat exchanger used for an automobile air conditioner, condensed water is generated during cooling. The condensed water becomes water droplets and accumulates between the fins, and further forms a bridge between the water droplets, causing problems such as a decrease in the cooling capacity of the automobile air conditioner and scattering of the water droplets. In order to solve such a problem, the surface of the heat exchanger fin is made hydrophilic to prevent a bridge from being formed by water droplets.

[0003] Generally, the surface hydrophilization treatment of heat exchanger fins is performed after forming an aluminum plate by forming an aluminum plate and assembling it. Generally, the surface hydrophilization treatment is performed by a method of subjecting an aluminum fin to a chromate treatment and then applying a hydrophilic surface treatment agent by means of dipping, spraying, showering or the like to form a film on the aluminum fin. Examples of the hydrophilic surface treating agent used in such a method include: (1) water glass (for example, see JP-A-59-13078); (2) water-soluble polyamide resin or the like. Solution containing an organic polymer resin as a main component (for example, see JP-A-61-250495).
No. Gazette).

In recent years, in order to prevent unpleasant odors and scattering of microorganisms at the start of heat exchanger operation due to microorganisms generated on the fin surface, use of a resin-based treating agent containing an antibacterial and antifungal agent has been used. It has been proposed (for example, Japanese Unexamined Patent Publication No.
366396).

However, in the film formed by applying the surface treating agent of the above (1), a powdery substance is formed on the surface of the film with the passage of time, and the powder is scattered during operation of the heat exchanger to cause cement odor, Alternatively, a chemical odor is generated. Furthermore, the water glass is hydrolyzed by the condensed water generated by the operation of the heat exchanger, making the fin surface alkaline and causing fin corrosion. The aluminum hydroxide powder formed by corrosion of the aluminum fins scatters and causes environmental protection problems.

On the other hand, the film formed by applying the surface treatment agent of the above (2) is not sufficiently water-resistant, and the film dissolves in coagulated water over time. Therefore, there are problems such as a decrease in the persistence of hydrophilicity on the fin surface and a decrease in corrosion resistance, and the cost is high.

In recent years, the size and weight of automobile air conditioners have been reduced, and the heat exchangers have been designed to be compact, so that the spacing between the fins has been narrowed, and thus higher hydrophilicity has been required. The hydrophilicity is generally represented by a contact angle with water, and the lower the contact angle with water, the higher the hydrophilicity, and thus a fin having a low contact angle with water (for example, 25 ° or less) is desired.

Further, recently, since a comfortable living space is required even in an automobile, generation of odor by an automobile air conditioner has been regarded as a problem. Conventional methods proposed to prevent the smell of the coating film at the beginning of use, the unpleasant odor at the start of operation due to the microorganisms generated in the air conditioner, and the scattering of the microorganisms (for example, JP-A-4-366396, Cannot provide a sufficient effect, and its improvement is required.

[0009] As described above, since the methods currently put into practical use cannot sufficiently meet the above-mentioned requirements, they are more excellent in hydrophilicity and corrosion resistance and have an antibacterial coating film having no odor problem. Development of fins is desired.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fin for an automotive air conditioner heat exchanger having excellent hydrophilicity and corrosion resistance.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies with the aim of solving the above problems, and as a result, have found that
By applying to the surface an antibacterial composition mainly composed of an antibacterial resin having both fungicidal properties and hydrophilicity, it is possible to suppress the generation of bacteria and mold for a long period of time and prevent the generation of unpleasant odors, Further, by roughening the surface of the film obtained by adding fine particles to the antibacterial composition, it becomes easier to wet with water, and as a result, in addition to the inherent hydrophilicity of the antibacterial resin, extremely high hydrophilicity, It has been found that a fin for an automobile air conditioner heat exchanger having water wettability and maintaining its effects over a long period of time can be obtained.

The present invention relates to a fin for an automotive air conditioner heat exchanger having a surface coated with an antibacterial composition containing an antibacterial resin and fine particles, wherein the antibacterial composition is JIS Z 2911 when formed into a film. The mold resistance is 2 or more by the evaluation method according to 6.2.2, the contact angle with water is 25 ° or less, and the film is
A fin for an automotive air conditioner heat exchanger having a mold resistance indication of 2 or more after immersion in water at 0 ° C. for 120 hours and a contact angle with the water of 25 ° or less. Thereby, the above object is achieved.

Preferably, the antibacterial resin is a copolymer of an antibacterial polymer containing an organic antibacterial component and a hydrophilic component.

Preferably, the antibacterial polymer is a copolymer having at least one of an ammonium base, a phosphonium base, and a sulfonium base in a main chain and / or a side chain.

The present invention is also an automobile air conditioner heat exchanger having the above-mentioned fin for an automobile air conditioner heat exchanger.

The fin material coated on the surface with the above antibacterial composition has excellent hydrophilicity and corrosion resistance over a long period of time, has no odor problem, and is most suitable for a fin for an automobile air conditioner heat exchanger.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The fins for a heat exchanger of an air conditioner of an automobile according to the present invention will be described below in detail.

Generally, a fin for an air conditioner heat exchanger is
This refers to a thin metal plate provided to allow the air conditioner refrigerant to cool.

The fin for an automotive air conditioner heat exchanger of the present invention has a structure in which an antibacterial composition is applied to a fin-shaped substrate.

As the substrate having the shape of a fin, any conventionally known substrate can be used. For example, aluminum is preferable.

The shape and size of the fin can be the shape and size of a conventionally known fin for a vehicle air conditioner heat exchanger, and preferably, the shape and size of a corrugate, 0.8 c
It has a size of mx 6.5 cm x 21 cm.

The antibacterial composition applied to the fins for an automotive air conditioner heat exchanger of the present invention contains an antibacterial resin and fine particles. Here, the antibacterial composition refers to a composition capable of killing bacteria and molds or suppressing their growth, and the antibacterial resin is a resin having antibacterial and antifungal properties.

The antibacterial resin used in the present invention comprises:
It is a copolymer of an antibacterial polymer containing an organic antibacterial component and a hydrophilic component. This antibacterial polymer is a polymer having an organic antibacterial component in the main chain or side chain.

Among organic antibacterial agents, relatively high antibacterial
Some have antifungal properties, but are generally easy to elute,
Antibacterial and antifungal effects do not last. Thus, by binding an organic antibacterial agent component to the main chain or side chain of the antibacterial polymer, elution can be prevented, and thus the antibacterial and antifungal effects can be maintained.

The hydrophilic component can impart hydrophilicity to the antimicrobial polymer. However, when a hydrophilic component is simply mixed with the polymer, the hydrophilic component gradually elutes during use, and the hydrophilicity of the antibacterial polymer decreases. Therefore, a hydrophilic component is copolymerized with the antibacterial polymer,
Alternatively, they are chemically bonded by a curing agent or the like. Thereby, elution of the hydrophilic component can be suppressed, and therefore,
It is possible to prevent the hydrophilicity from decreasing over time.

The organic antimicrobial component is a general term for natural extracts, low molecular weight organic compounds and polymers having antibacterial properties, and generally refers to compounds containing elements such as nitrogen, sulfur and phosphorus. For example, natural extracts include chitin, chitosan, wasabi extract, mustard extract, hinokitiol,
Tea extract and the like, as low molecular organic compounds, include quaternary ammonium salts such as allyl isothiocyanate, polyoxyalkylenetrialkylammonium, benzalkonium chloride, hexamethylenebiguanide hydrochloride; organic silicon quaternary ammonium salts; Quaternary phosphonium salts such as tri-n-butylhexadecylphosphonium chloride, tri-n-butyltetradecylphosphonium chloride, tri-n-butylhexadecylphosphonium chloride; phenylamide, biguanide, tetraalkylphosphonium sulfoisophthalate Examples thereof include, but are not limited to, salts or diesters thereof, imidazole / thiazole compounds, thiocarbide compounds, pyridine / quinoline compounds, and the like.

Among the above-mentioned organic antibacterial agents, onium salts such as ammonium base, phosphonium base, sulfonium base and the like, and antibacterial active groups such as phenylamide group and biguanide group have a main chain or a chain, because of easy binding to antibacterial polymer. A polymer bonded to a side chain is preferable, and a phosphonium salt-based compound having high antibacterial activity and a broad antibacterial spectrum is particularly preferable.

The hydrophilic component is a substance having an excellent affinity for water, that is, a substance which can be dissolved, dispersed or swelled in water, or a water-retaining or moisture-retaining substance. A low molecular weight organic compound or high molecular weight compound containing a hydrophilic group such as an amide group, a carboxyl group or its alkali metal salt, a sulfonic acid group or its alkali metal salt or a derivative thereof, or containing two or more ether bonds in one molecule. It is. Specific examples of the hydrophilic component include polyvinyl alcohol, starch, a homopolymer or copolymer of acrylic acid, a homopolymer or copolymer of methacrylic acid, and a homopolymer or copolymer of maleic anhydride (for example, maleic anhydride). Styrene copolymer), polyvinyl sulfonic acid or its copolymer or an alkali metal salt thereof, polyethylene glycol (also known as polyethylene oxide), polypropylene glycol, polyethylene propylene glycol, polyalkylene glycol such as polytetramethylene glycol,
Glycerin, polyols such as polyglycerin or polymers thereof, glycerin, polyglycerin, water-soluble modified cellulose (for example, hydroxyethylcellulose, methylcellulose, methylhydroxypropylcellulose,
Sodium carboxycellulose, cellulose nitrate carboxymethyl ether) and the like.

As the antibacterial resin in the present invention, a dicarboxylic acid component and a glycol component are mainly used as main components, and a sulfonic acid group-containing aromatic dicarboxylic acid represented by the following general formula (Chemical Formula 1) is used as an organic antibacterial component. A copolymer of a polyester resin having an acid phosphonium base and a hydrophilic substance is preferred.

[0030]

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(Where A is an aromatic group, X ¹ and X ² are each independently an ester-forming functional group, and R ¹ , R ² , R ³ and R ⁴ are each independently An alkyl group, at least one of which has 10 carbon atoms.
-20 alkyl groups).

Preferably, the polyester resin contains a phosphonium base of a sulfonic acid group-containing aromatic dicarboxylic acid represented by the above general formula (Chemical Formula 1) in an amount of preferably 1 to 50 mol%, more preferably 1 to 50 mol%, based on all acid components. Is 3 to 20 mol%
It is a copolymerized polyester resin.

When the phosphonium base of the sulfonic acid group-containing aromatic dicarboxylic acid is 1 mol% or less based on the total acid components,
Antibacterial polymers having good antibacterial and antifungal properties may not be obtained. If the phosphonium base of the sulfonic acid group-containing aromatic dicarboxylic acid is to be copolymerized in an amount of 50 mol% or more based on the total acid components, gelation occurs during the polymerization of the polyester, which makes polymerization difficult.

The dicarboxylic acid component includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. Moreover, you may use in combination with an alicyclic dicarboxylic acid, an aliphatic dicarboxylic acid, a heterocyclic dicarboxylic acid, an oxycarboxylic acid, a polyvalent carboxylic acid, etc. within the range which does not impair the content of the invention. Examples of the alicyclic dicarboxylic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, azelaic acid, eicoic acid, dimer acid and derivatives thereof. Heterocyclic dicarboxylic acids include pyridine carboxylic acid and its derivatives. Examples of the oxycarboxylic acid include p-oxybenzoic acid. Examples of the polyvalent carboxylic acid include trimellitic anhydride, pyromellitic anhydride and the like.

In consideration of practical durability when the obtained antibacterial composition is formed into a film, it is preferable that 70 mol% or more of all dicarboxylic acid components are aromatic dicarboxylic acids. As the dicarboxylic acid component other than the aromatic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, and sebacic acid are particularly preferable.

The glycol components include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,
4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-
Methyl-1,5-pentanediol, 2-methyl-1,
5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-
Alkylene glycols such as decanediol, 1,2-
Alicyclic glycols such as cyclohexanedimethanol,
Alkylene oxide adducts of bisphenol A or F, diethylene glycol, polyethylene glycol,
Neopentyl glycol of hydroxypivalic acid (HP
N), polypropylene glycol, polytetramethylene glycol and the like. The glycol component,
A small amount of a compound having an amide bond, a urethane bond, an ether bond, or a carbonate bond may be contained.

Considering the practical durability when the obtained antibacterial composition is formed into a film, the glycol component is
Ethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 1,5-pentanediol, 3-methyl-1,
5-pentanediol, 1,4-cyclohexanedimethanol and the like are preferred. Furthermore, as long as the content of the invention is not impaired, it may be used in combination with a polyhydric polyol such as trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol.

Examples of the phosphonium salt of the aromatic sulfonic acid group-containing aromatic dicarboxylic acid include trisulfoisophthalic acid.
n-butyldecylphosphonium salt, tri-n-butyloctadecylphosphonium sulfoisophthalate, tri-n-butylhexadecylphosphonium sulfoisophthalate, tri-n-butyltetradecylphosphonium sulfoisophthalate, sulfoisophthalic acid-n -Butyldodecylphosphonium salt, 4-sulfonaphthalene-2,7
Tri-n-butyldecylphosphonium dicarboxylate, tri-n-butyloctadecylphosphonium 4-sulfonaphthalene-2,7-dicarboxylate, tri-n-butylhexadecyl 4-sulfonaphthalene-2,7-dicarboxylate Phosphonium salt, 4-sulfonaphthalene-
Tri-n-butyltetradecylphosphonium 2,7-dicarboxylate; tri-n-butyldodecylphosphonium 4-sulfonaphthalene-2,7-dicarboxylate; and the like. From the viewpoint of antibacterial activity, tri-n-butylhexadecylphosphonium sulfoisophthalate, tri-n-butyltetradecylphosphonium sulfoisophthalate, and tri-n-butyldodecylphosphonium sulfoisophthalate are particularly preferred.

The phosphonium salts of the aromatic sulfonic acid group-containing aromatic dicarboxylic acids include tri-n-butylhexadecylphosphonium bromide, tri-n-butyltetrafluorosulfonic acid and its sodium, potassium and ammonium salts. It is obtained by reacting a phosphonium salt such as decylphosphonium bromide and tri-n-butyldodecylphosphonium bromide. The solvent used in the above reaction is not particularly limited,
Water is most preferred.

The method for producing the polyester resin is not particularly limited, and may be any method, for example, a direct polymerization method in which a dicarboxylic acid and a glycol are directly reacted and the obtained oligomer is polycondensed, After a transesterification reaction between the dimethyl ester and glycol,
Polycondensation, transesterification, and the like can be applied.

The polyester resin is copolymerized with a hydrophilic component. By copolymerizing the hydrophilic component, hydrophilicity can be imparted to the polyester resin, and the antibacterial and antifungal properties are remarkably improved. When the hydrophilic component is simply mixed with the polyester resin, the hydrophilic component gradually elutes during use, and the hydrophilicity of the antibacterial resin decreases. By copolymerizing the hydrophilic component with the polyester resin, elution of the hydrophilic component can be suppressed, and therefore,
It is possible to prevent a decrease in hydrophilicity over time.

The method of copolymerizing the above hydrophilic component with a polyester resin includes: 1) a method of copolymerizing a dicarboxylic acid or glycol containing a metal salt of sulfonic acid with a polyester resin; 2) a method of copolymerizing an alkylene glycol with a polyester resin. 3) a method of graft-polymerizing a vinyl-based monomer having a hydrophilic group onto a polyester resin. Examples of the dicarboxylic acid or glycol containing a sulfonic acid metal base used in the method 1) include 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5- (4-sulfophenoxy) isophthalic acid. Metal salt, or 2-sulfo-
Metal salts such as 1,4-butanediol and 2,5-dimethyl-3-sulfo-2,5-hexanediol are exemplified. Examples of the alkylene glycol used in the method 2) include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of the vinyl monomer having a hydrophilic group which can be used in the method 3) of graft-polymerizing the hydrophilic component to a polyester resin include monomers having a carboxyl group, a hydroxy group, a sulfonic acid group, an amide group and the like. Monomers having a group that can be converted to a hydrophilic group (for example, an acid anhydride group, a glycidyl group, a chloro group, and the like) are included. For example, monomers containing a carboxyl group or a salt thereof, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof; methyl acrylate, ethyl acrylate, n-
Propyl acrylate, isopropyl acrylate, n
Alkyl acrylates such as -butyl acrylate and t-butyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and t-butyl methacrylate;
Hydroxy group-containing monomers such as hydroxyethyl acrylate and 2-hydroxyethyl methacrylate; acrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-
Methylol methacrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide,
Amide group-containing monomers such as N, N-dimethylolacrylamide and N-phenylacrylamide; epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether; styrene sulfonic acid, vinyl sulfonic acid and salts thereof. A monomer containing a sulfonic acid group or a salt thereof; and a monomer containing an acid anhydride group such as maleic anhydride and itaconic anhydride. A vinyl monomer having a carboxyl group is most preferred.

The above-mentioned vinyl monomers having a hydrophilic group can be used in combination with one or two kinds of vinyl monomers having no hydrophilic group. Examples of the vinyl monomer having no hydrophilic group include vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, acrylonitrile, methacrylonitrile, vinylidene chloride, vinyl acetate, and vinyl chloride.

The molar ratio of the vinyl monomer having a hydrophilic group to the vinyl monomer having no hydrophilic group is preferably 30/70 to 100/0, more preferably 40/60 to 100. / 0, most preferably 5
It is in the range of 0/50 to 100/0. If the ratio of the vinyl monomer having a hydrophilic group is less than 30% by mole, the effect of increasing the hydrophilicity of the whole obtained antibacterial resin is not sufficiently exerted.

As a method for grafting the above-mentioned vinyl monomer having a hydrophilic group to a polyester resin, a known graft polymerization method can be used. Typical examples thereof include, for example, the following methods: a radical polymerization method in which radicals are generated in a main chain polymer substance by light, heat, radiation, or the like, and then the monomers are graft-polymerized;
A cationic polymerization method in which a cation is generated in a main chain polymer substance using a catalyst such as AlCl ₃ or TiCl ₄ and a monomer is graft-polymerized; an anion is formed in the main chain polymer substance using metal Na, metal Li, or the like. An anionic polymerization method of generating and graft-polymerizing a monomer.

Further, there is a method in which a polymerizable unsaturated double bond is previously introduced into a polymer material of the main chain, and a vinyl monomer is reacted with the polymerizable unsaturated double bond. Examples of the monomer having a polymerizable unsaturated double bond used in this method include fumaric acid, maleic acid, maleic anhydride, tetrahydromaleic anhydride, 2,5-norbornene dicarboxylic acid, and the like. And 2,5-norbornene dicarboxylic acid are most preferred.

Further, there is a method in which a high molecular substance serving as a main chain having a functional group introduced into a side chain is reacted with a branch polymer having a group which reacts with the functional group at a terminal. For example, -OH group, -SH group, -NH ₂ group, -COO
A polymer having a hydrogen donating group such as an H group or a -CONH ₂ group, and -N = C = O group, = C = C = O group at one end;

[0049]

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A method of reacting with a vinyl copolymer having a hydrogen accepting group, or a method of conducting the reaction in the reverse combination.

The weight ratio of the polyester resin as the main chain of the antibacterial resin to the vinyl monomer to be grafted is as follows:
Preferably it is in the range of 99/1 to 30/70, more preferably 95/5 to 50/50, most preferably 85/50.
It is in the range of 15 to 65/35. When the weight ratio of the main-chain polyester resin is less than 30%, the graft-polymerizable vinyl monomer remains without completely reacting, so that the main-chain polyester resin has properties such as heat resistance, processability, and water resistance. Can be compromised. The weight ratio of the main chain polyester resin is 9
If it exceeds 9%, it is difficult to obtain hydrophilicity as the whole antibacterial resin.

The antimicrobial resin may contain a curing agent capable of reacting with either the polyester resin or the hydrophilic component. Examples of such a curing agent include an alkyl etherified aminoformaldehyde resin, an epoxy compound, and an isocyanate compound.

The alkyl etherified aminoformaldehyde resin which can be used as the curing agent is, for example, formaldehyde alkyl etherified with an alcohol having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol and n-butanol. Or urea, N, N
A condensation product with ethylene urea, dicyandiamide, aminotriazine and the like. Specific examples include methoxylated methylol benzoguanamine, methoxylated methylol-N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, methoxylated / butoxylated mixed methylol melamine. And the like. From the viewpoint of processability, methoxylated methylol melamine, butoxylated methylol melamine,
And methoxylated / butoxylated mixed methylolmelamine are preferred, and each can be used alone or in combination.

Examples of the epoxy compound that can be used as the curing agent include diglycidyl ethers of bisphenol A and oligomers thereof, diglycidyl ethers of hydrogenated bisphenol A and oligomers thereof, diglycidyl orthoisophthalate, diglycidyl isophthalate, and the like. Diglycidyl terephthalate, p
-Diglycidyl oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene glycol diglycidyl ether, propylene glycol Diglycidyl ether, 1,4-butanediol diglycidyl ether,
1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, triglycidyl trimellitate, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidylpropylene urea, glycerol triglycidyl ether, triglycidyl ether Examples include methylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, and triglycidyl ethers of glycerol alkylene oxide adducts.

Examples of the isocyanate compound that can be used as the above-mentioned curing agent include aromatic or aliphatic diisocyanates and trivalent or higher polyisocyanates. Either low molecular weight compounds or high molecular weight compounds may be used. For example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate or trimers of these isocyanate compounds, and excess of these isocyanate compounds Quantity and
Examples of the compound include a terminal isocyanate group-containing compound obtained by reacting a low molecular weight active hydrogen compound or a high molecular weight active hydrogen compound. As low molecular active hydrogen compounds,
For example, ethylene glycol, propylene glycol,
Trimethylolpropane, glycerin, sorbitol,
Examples include ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine. Examples of the polymer active hydrogen compound include various polyester polyols, polyether polyols, and polyamides. The isocyanate compound may be a blocked isocyanate. The blocked isocyanate can be obtained by subjecting the above-mentioned isocyanate compound to an isocyanate blocking agent to undergo an addition reaction using an appropriate known method. Examples of the isocyanate blocking agent include phenols such as phenol, thiophenol, methylthiophenol, ethylthiophenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; oximes such as acetoxime, methylethylketoxime, and cyclohexanone oxime; Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; t-butanol and t-
Tertiary alcohols such as pentanol; ε-caprolactam, δ-valerolactam, γ-butyrolactam, β
Lactams such as propyrolactam; and aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetate, and malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; And the like.

Further, these curing agents can be used in combination with other known curing agents or accelerators selected according to their types.

The antibacterial composition of the present invention further contains fine particles in addition to the above antibacterial resin.

The fine particles include organic particles and inorganic particles. As the organic particles, typically, cellulose particles, sodium acrylate polymer particles, sodium acrylate-acrylamide copolymer particles, acrylic acid-vinyl alcohol copolymer particles, vinyl acetate-methyl acrylate copolymer Examples include saponified particles, starch-polyacrylonitrile hydrolyzed particles, and starch-polyacrylate crosslinked particles. Typical examples of the inorganic particles include silica, alumina, titanium oxide, zirconium oxide, iron oxide, chromium oxide, calcium carbonate, calcium phosphate, calcium sulfate, magnesium carbonate, and barium sulfate. Some inorganic particles have a very small primary particle diameter, but the secondary particle diameter is preferably within the following range.

The fine particles preferably have an average particle size of 0.1.
It is from 0.05 to 10 μm, more preferably from 0.10 to 5 μm, and most preferably from 0.15 to 3 μm. When the average particle diameter of the fine particles is 0.05 μm or less, when the obtained antibacterial composition is formed into a film, the surface of the film is insufficiently roughened, and the hydrophilicity is not sufficiently exhibited. On the other hand, when the average particle diameter of the fine particles is 10 μm or more, the dispersibility of the fine particles in the antibacterial composition is deteriorated, and a good film may not be produced.

The content of the fine particles in the antibacterial composition of the present invention is preferably 10 to 50% by weight, more preferably 12 to 45% by weight, and most preferably 15 to 40% by weight.
It is. When the content of the fine particles is 10% by weight or less, when the obtained antibacterial composition is formed into a film, the surface of the film is insufficiently roughened, and it is difficult to sufficiently exhibit hydrophilicity. The upper limit of the content of the fine particles is not specified because it greatly varies depending on the density of the fine particles. However, if the content of the fine particles is too large, the surface hardness of the film becomes extremely low when the obtained antibacterial composition is formed into a film.

When the antibacterial composition was formed into a film, the contact angle between the surface of the obtained film and water was 25 °.
Or less, preferably 20 ° or less,
Most preferably, it is 15 ° or less, and JIS Z
The mold resistance is 2 or more by the evaluation method according to 2911 6.2.2. Here, the film includes a film of the antibacterial composition alone, a coating film and a film formed on the substrate, a film laminated on the substrate, and the like, and has excellent water resistance, for example, at 40 ° C. Even after immersion in water for 120 hours, the mold resistance reading is 2 or more and the contact angle with water is 25 ° or less.

As a method for forming a film of the above-mentioned antibacterial composition on the surface of the fin for a heat exchanger, the above-mentioned antibacterial composition is appropriately adjusted to a concentration suitable for coating, and a conventional coating method such as dip coating or showering is used. Apply to heat exchanger fins molded by painting, spray painting, roll painting, etc.
Next, a method of drying by heating is used.

In the present invention, among the above coating methods, dip coating is particularly preferred. When the dip coating method is used, the solid concentration is usually 2 to 30% by weight, preferably 5 to 30% by weight.
In an aqueous bath containing the antibacterial composition adjusted to the range of 10% by weight, the fins for heat exchanger pre-molded and assembled are immersed for, for example, 0.5 to 1 minute, pulled up, and then subjected to appropriate baking conditions. For example, a film can be formed by baking at 100 to 180 ° C. for 1 to 10 minutes.

In the present invention, the above antibacterial composition forms a practical hydrophilic film even when applied to a heat exchanger fin that has been subjected to only degreasing and washing, but forms a film having excellent corrosion resistance. Therefore, it is preferred that the fins for the heat exchanger that have been sufficiently degreased are subjected to a phosphoric acid chromate treatment or a chromate chromate treatment, which is a conventionally known surface treatment for aluminum, before being applied.

The antibacterial film thus formed is
The film thickness is in the range of 0.2 to 5 μm, preferably 0.5 to 3 μm. When the film thickness is less than 0.2 μm, the hydrophilicity and antibacterial properties are insufficiently maintained, and when it exceeds 5 μm, the heat radiation efficiency of the heat exchanger fins may be reduced.

As described above, the fin for an automobile air conditioner heat exchanger of the present invention is obtained.

As described above, the fin for an automobile air conditioner heat exchanger of the present invention has a long-lasting effect by applying an antibacterial composition mainly composed of an antibacterial resin having both antibacterial and antifungal properties and hydrophilicity to the surface. For a long time, the generation of unpleasant odors can be prevented by suppressing the generation of bacteria and mold, and the surface of the film obtained by adding fine particles to the antibacterial composition is roughened, so that it becomes easier to wet with water. As a result, in addition to the inherent hydrophilicity of the antibacterial resin, the resin has extremely high hydrophilicity and water wettability, and its effects are maintained for a long time.

The fin for an air conditioner heat exchanger of the present invention thus manufactured is attached to an automobile air conditioner heat exchanger by a conventionally known method. As the members for the automotive air conditioner other than the fins, all conventionally known members can be used. If it is a fin for an automobile air conditioner heat exchanger of the present invention, for example, 5 mm to 20 mm, preferably 5 mm
Even when the fins are mounted at extremely narrow fin intervals of 8 mm to 8 mm, water aggregation between the fins can be effectively prevented for a long period of time. Furthermore, with such a fin spacing design, the heat exchanger as a whole, for example, is 30 cm × 1
0cm × 44cm or less, further 23cm × 7cm × 2
An extremely small automobile air conditioner having a size of 3 cm or less can be manufactured.

[0069]

EXAMPLES The fins for a heat exchanger of an automobile air conditioner according to the present invention will be described in more detail with reference to the following examples. These examples are illustrative of the present invention and do not limit the present invention.

(Production Example of Polyester Resin) Dimethyl terephthalate 505 was placed in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 369 parts of dimethyl isophthalate, 161 parts of tri-n-butyldodecylphosphonium salt of 5-sulfodimethylisophthalic acid, 450 parts of ethylene glycol, 450 parts of neopentyl glycol, and 0.52 part of tetra-n-butyl titanate, 4 to 160-220 ° C
The transesterification was performed over time. Next, 29 parts of fumaric acid was added, the temperature was raised to 200 to 220 ° C. over 1 hour, and the pressure of the reaction system was gradually reduced. Then, the reaction was allowed to proceed under a reduced pressure of 0.2 mmHg for 2 hours to obtain polyester (A-1). Obtained. The composition of the polyester is as shown in Table 1.

In the same manner, polyesters (A-2, A-3, A-4) shown in Table 1 were produced.

[0072]

[Table 1]

(Production Example 1 of Aqueous Dispersion of Graft Polymer) In a reactor equipped with a stirrer, a thermometer, a reflux device and a metered addition device, 300 parts of polyester (A-1), 360 parts of methyl ethyl ketone and 120 parts of isopropyl alcohol
The polyester was dissolved under reflux while heating and stirring. After the polyester is completely dissolved, acrylic acid 6
A mixture of 0 parts, 40 parts of ethyl acrylate and 1.5 parts of octyl mercaptan, and a solution prepared by dissolving 6 parts of azobisisobutyronitrile in a mixture of 90 parts of methyl ethyl ketone and 30 parts of isopropyl alcohol were prepared.
These were respectively dropped into the polyester solution over 2 hours, and reacted for further 3 hours to obtain a graft polymer solution. Next, the graft polymer solution was cooled to room temperature, neutralized by adding 56 parts of triethylamine, and then 800 parts of ion-exchanged water was added and stirred for 30 minutes. Thereafter, the organic solvent remaining in the dispersion was distilled off by heating to obtain an aqueous graft polymer dispersion (B-1).

In a similar manner, the polyester (A-
2, A-3) was graft-polymerized to obtain a graft polymer aqueous dispersion (B-2, B-3).

(Production Example of Polyester Aqueous Dispersion) In a reactor equipped with a stirrer, a thermometer, a reflux device, and a metering dropping device, 300 parts of polyester (A-4), 360 parts of methyl ethyl ketone, and 120 parts of isopropyl alcohol were put. The polyester was dissolved by heating and stirring under reflux.
Then, after cooling the polyester solution to room temperature,
800 parts of ion-exchanged water was added and stirred for 30 minutes. Thereafter, the organic solvent remaining in the dispersion is removed by heating,
An aqueous polyester dispersion (B-4) was obtained.

(Production Example 2 of Graft Polymer Aqueous Dispersion) In a reactor equipped with a stirrer, a thermometer, a reflux device, and a metered addition device, 100 parts of polyester (A-1), 360 parts of methyl ethyl ketone and 120 parts of isopropyl alcohol
The polyester was dissolved under reflux while heating and stirring. After the polyester has completely dissolved, acrylic acid 1
A mixture of 80 parts, 120 parts of ethyl acrylate and 4.5 parts of octyl mercaptan, and a solution prepared by dissolving 18 parts of azobisisobutyronitrile in a mixture of 270 parts of methyl ethyl ketone and 90 parts of isopropyl alcohol were prepared. These were respectively dropped into the polyester solution over 2 hours, and reacted for further 3 hours to obtain a graft polymer solution. Next, the graft polymer solution was cooled to room temperature, neutralized by adding 150 parts of triethylamine, and then 800 parts of ion-exchanged water was added and stirred for 30 minutes. Thereafter, the organic solvent remaining in the dispersion was removed by heating to obtain an aqueous dispersion of graft polymer (B-5).

With respect to the metal substrates obtained in the following examples and comparative examples, the following items were tested.

(Antibacterial test) E. coli diluted with 1/50 broth Bacterial solution coli (E. coli) (ATCC 25922): The 0.1ml of (concentration 10 ⁵ cells / ml), was added dropwise to a pre-autoclaving was 5 cm × 5 cm size sample metal substrate of the coating film surface, the A high-pressure steam-sterilized polyethylene film was adhered to the coating surface of the sample metal substrate. The obtained test piece was transferred to a sterile petri dish and cultured at 37 ° C. for 24 hours. Then, the bacteria on the film were transferred to SCDLP medium 1
The cells were washed with 0 ml, diluted 10-fold, spread on an ordinary agar plate, and the number of bacteria was counted 24 hours later. The antibacterial rate was calculated by the formula: Antibacterial rate = [1- (measured bacterial count / initial bacterial count)] × 100.

(Mold prevention test) JISZ29116.
5 cm on an inorganic salt agar plate according to 2.2.
A sample metal substrate having a size of × 5 cm was adhered, and 0.2 ml of a mixed solution obtained by adding 5% sucrose to a spore suspension of the following five mold strains was sprayed and cultured at 27 ± 1 ° C. for 28 days. Was evaluated for growth status. Test strain: Aspergillus niger (ATCC627)
5) Penicillium citrinum (ATCC
9849) Chaetomium globosum (ATCC6
205) Rhizopus stolonifer (ATCC1
0404) Aureobasidium pullulans (I
FO6353) Mold resistance display: 1: Mold growth is 1/3 or more of the surface area of the sample metal substrate 2: Mold growth is within 1/3 of the surface area of the sample metal substrate 3: Mold growth is not recognized (water contact) Angle) Using a contact angle meter CA-X (manufactured by Kyowa Kagaku Co., Ltd.), water contact of the coating film of the antibacterial composition on the sample metal substrate having a size of 5 cm × 5 cm at 25 ° C. and 50% relative humidity. The corner was measured.

(Water Leakage Property) Judgment was made based on the state of adhesion of water by spraying to a sample metal substrate having a size of 5 cm × 5 cm. In Table 2, ◎ indicates overall water leakage, は indicates repelling water within 10% of the surface area of the sample metal substrate, Δ indicates repelling water within 50%, and × indicates repelling water of 50% or more.

(Odor Suppressing Property) A sample metal substrate having a size of 5 cm × 5 cm was left in a thermo-hygrostat at a temperature of 30 ° C. and a relative humidity of 90% for 2 weeks to evaluate the odor. In Table 2, ◎ indicates no odor, は indicates almost no odor, Δ indicates a slight odor, and X indicates a state in which an odor is clearly felt.

(Water resistance) 1 L of distilled water in which a sample metal substrate having a size of 5 cm × 5 cm was controlled at 40 ° C. ± 1 ° C.
After being immersed in for 120 hours, taken out and dried at room temperature, the above five evaluations were performed and compared with the evaluation before immersion in distilled water.

Example 1 A liquid 1 was prepared by diluting the above aqueous dispersion of graft polymer (B-1) with water until the solid content became 10%.
To 00 parts, 5 parts of silica fine particles having an average secondary particle size of 0.2 μm (Aerosil # 200 manufactured by Nippon Aerosil Co., Ltd.) was added, and the mixture was stirred until the silica fine particles were sufficiently dispersed to obtain an antibacterial coating solution. A coating amount of 10 mm on the surface of a 0.2 mm thick aluminum alloy plate by coating type chromate treatment.
An inorganic corrosion resistant film was previously formed by coating so as to be mg / m ² . Then, after applying the antibacterial coating solution by a dip coating method so that the coating amount of the solid content is 1 g / m ² ,
Heat treatment was performed at 150 ° C. for 5 minutes to prepare a resin-laminated metal substrate having a coating film of the antibacterial composition on the surface. The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

Example 2 Graft Polymer Aqueous Dispersion (B
A resin-laminated metal substrate having a coating film of an antibacterial composition on the surface was prepared in the same manner as in Example 1, except that the graft polymer aqueous dispersion (B-2) was used instead of -1). The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

(Comparative Example 1) Graft polymer aqueous dispersion (B
A resin-laminated metal substrate having a coating film of an antibacterial composition on the surface was prepared in the same manner as in Example 1 except that the graft polymer aqueous dispersion (B-3) was used instead of -1). The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

(Comparative Example 2) Graft polymer aqueous dispersion (B
A resin laminated metal substrate having a coating film of an antibacterial composition on the surface was prepared in the same manner as in Example 1 except that the aqueous polyester dispersion (B-4) was used instead of -1). The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

(Comparative Example 3) 5 parts of silica fine particles (Aerosil manufactured by Nippon Aerosil Co., Ltd.) and a polyacrylic acid aqueous solution (weight: 100 parts) were prepared by diluting polyester (B-4) with water to a solid content of 10%. Average molecular weight 500
(0, 50% solid content) and stirred until the silica fine particles were sufficiently dispersed to obtain an antibacterial coating solution. An inorganic corrosion resistant film was previously formed on the surface of an aluminum alloy plate having a thickness of 0.2 mm by a coating type chromate treatment so that the film amount was 10 mg / m ² . Next, the antibacterial coating solution is applied by a dip coating method to a solid content of 1%.
g / m ^2, and heat-treated at 150 ° C. for 5 minutes to prepare a resin-laminated metal substrate having a surface coated with an antibacterial composition. The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

(Comparative Example 4) Graft polymer aqueous dispersion (B
A resin-laminated metal substrate having a coating film of an antibacterial composition on the surface was prepared in the same manner as in Example 1, except that the graft polymer aqueous dispersion (B-5) was used instead of -1). The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

(Comparative Example 5) An inorganic corrosion-resistant film was previously formed on a surface of an aluminum alloy plate having a thickness of 0.2 mm by a coating-type chromate treatment so as to have a film amount of 10 mg / m ² . Next, a solution obtained by diluting the aqueous graft polymer dispersion (B-1) with water until the solid content becomes 10% is applied by a dip coating method so that the applied amount of the solid content is 1 g / m ^2, and then 150 C. for 5 minutes to prepare a resin-laminated metal substrate having a coating film of the antibacterial composition on the surface. The characteristics of the resin-laminated metal substrate were measured by the method described above. Table 2 shows the results.

[0090]

[Table 2]

From Table 2, the following became clear: (1) The metal substrates obtained in Examples 1 and 2 had good antibacterial efficiency, antifungal property, water contact angle before and after the water resistance test. Shows water leakage and odor prevention. (2) Since the metal substrate obtained in Comparative Example 1 did not contain an organic antibacterial agent component (tri-n-butyldodecylphosphonium 5-sulfodimethylisophthalate) in the polyester, it had antibacterial and antifungal properties. And does not have odor prevention properties. (3) Since the metal substrate obtained in Comparative Example 2 did not graft a hydrophilic component (acrylic acid) on polyester,
The water contact angle is large and the water wettability is insufficient. Furthermore, the antibacterial rate is significantly lower than the metal substrates obtained in Examples 1 and 2. (4) The metal substrate obtained in Comparative Example 3 was insufficient in water resistance because the hydrophilic component (polyacrylic acid) was simply blended with the polyester, and the coating of the antibacterial composition was not performed during the water resistance test. The film almost peeled off, whereby the antibacterial rate, antifungal property, water contact angle, water wettability and odor control were significantly deteriorated after the water resistance test. (5) The metal substrate obtained in Comparative Example 4 had insufficient water resistance because the graft amount of the hydrophilic component (acrylic acid) to the polyester was too large, and a coating film of the antibacterial composition during the water resistance test. Almost peeled off, thereby significantly deteriorating the antibacterial rate, antifungal property, water contact angle and water wettability after the water resistance test. (6) The metal substrate obtained in Comparative Example 5 had a large water contact angle and was poor in water wettability because silica fine particles were not added to the polyester.

Using the methods and materials in each of the above Examples and Comparative Examples, only the shape was the shape of the fin for an air conditioner heat exchanger of an automobile (0.7 cm × 6.5 cm × 2).
1 cm) to produce a fin for an automobile air conditioner heat exchanger. The fins for a vehicle air conditioner heat exchanger thus obtained were arranged at 0.8 mm intervals to produce a vehicle air conditioner heat exchanger.

Using each of these air conditioners, water wettability and antibacterial properties were evaluated.

In the same examples as those in the above examples, the durable water contact angle after 72 hours of running tap water was not significantly larger than the initial water contact angle. Further, 72 hours after tap water flow, the antibacterial properties were evaluated in accordance with the above (antibacterial test). The viable cell rates of Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus were 1/100 or less. . Therefore, no condensed water accumulated between the fins, and no unpleasant odor was generated. In the same comparative examples, the durable water contact angle after 72 hours of running tap water was significantly larger than the initial water contact angle. Furthermore, 72 hours after tap water flow, when the antibacterial property was evaluated according to the above (antibacterial test), a significant number of viable bacteria was observed. Therefore, in the same thing as the comparative example 1, an unpleasant odor due to fungi and mold is generated, and in the same thing as the comparative example 2, the condensed water is accumulated between the fins,
The number of bacteria increases, and condensed water accumulates between the fins in the cases similar to Comparative Examples 3 and 4, and further, an unpleasant odor due to fungi and mold is generated. Sex was bad.

[0095]

According to the present invention, by applying an antibacterial composition having an antibacterial resin having both antibacterial and antifungal properties and hydrophilicity to the surface, the generation of bacteria and mold can be prevented for a long period of time. It is possible to suppress the generation of unpleasant odor by suppressing, and furthermore, by adding the fine particles to the above antibacterial composition to roughen the surface of the film, it becomes easier to wet with water, and as a result, the antibacterial resin A fin for an automotive air conditioner heat exchanger having extremely high hydrophilicity and water wettability in addition to the original hydrophilicity and maintaining its effects over a long period of time can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/14 C09D 5/14 (72) Inventor Satoshi Hayakawa 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo (72) Inventor Hideto Ohashi 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Affiliation Research Institute (72) Inventor Shigetsugu Konagaya 2-1-1 Katata, Otsu City, Shiga Prefecture No. Toyobo Co., Ltd. Research Institute (72) Inventor Kazunori Yamaguchi 1 Nakashinki, Hashime-cho, Okazaki City, Aichi Prefecture Mitsubishi Motors Corporation F-term (reference) 4H011 AA02 BA04 BB04 BB07 BB09 BB10 BB17 BB22 BC19 DD06 DH02 DH03 DH10 DH25 4J038 BA011 BA022 BA121 CE021 CG031 CG081 CG092 CG172 DD001 DD241 EA011 GA08 GA13 GA14 HA216 HA286 HA376 HA416 HA446 JB11 JB29 JB32 JC03 JC2 9 KA20 MA02 NA06 PB07 PC02

Claims (4)

[Claims] 1. A fin for an automobile air conditioner heat exchanger having a surface coated with an antibacterial composition containing an antibacterial resin and fine particles, wherein the antibacterial composition is a JIS Z 2911 film. 2.
The mold resistance display by an evaluation method according to 2 is 2 or more, the contact angle with water is 25 ° or less, and the mold resistance display after immersing the film in 40 ° C. water for 120 hours. Is 2 or more, and the contact angle with the water is 25 °
The following are the fins for an automotive air conditioner heat exchanger. 2. The fin for an automotive air conditioner heat exchanger according to claim 1, wherein the antibacterial resin is a copolymer of an antibacterial polymer containing an organic antibacterial component and a hydrophilic component. 3. The heat exchange of an automobile air conditioner according to claim 2, wherein the antibacterial polymer is a copolymer having at least one of an ammonium base, a phosphonium base, and a sulfonium base in a main chain and / or a side chain. Dexterous fins. 4. A vehicle air conditioner heat exchanger having the vehicle air conditioner heat exchanger fin according to claim 1.