JP6866465B1 - Coating liquid, coating film, substrate having coating film, and air conditioner having coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating film having high liquid repellency and low surface resistance, and a coating liquid for forming the coating film. A coating liquid containing at least a fluorine-containing organic compound, silicon dioxide particles 3, a carboxy group-containing resin having a glass transition temperature of 60 ° C. or higher, and a solvent, wherein the solvent contains an alcohol having a boiling point of 100 ° C. or lower. [Selection diagram] Fig. 1

Description

The present invention relates to a base material having a coating film that makes it difficult for oil stains, dust, etc. to adhere to the surface, and a coating liquid that forms the coating film. The present invention also relates to an air conditioner having a coating film on the inside of a housing, the surface of a blower fan, the surface of a filter, or the like. An air conditioner is a heat exchanger that circulates indoor air to obtain heated, cooled, or dehumidified air, and releases these air into the room to obtain the temperature of the indoor air or the temperature of the indoor air. It is a device that controls humidity appropriately, and is generally called an air conditioner or an air conditioner.

It is a common experience for everyone to get dirty on the surface of home appliances and furniture due to the adhesion of dirt components such as oil mist and dust floating in the air to the surface. Depending on the dirt, it becomes a nutrient for bacteria, which causes the growth of mold and pathogens, which may hinder life. Therefore, it is desired that these stains do not adhere to home appliances, furniture, etc. as much as possible.

Among home appliances, the one that is particularly exposed to dirt is an air conditioner generally called an air conditioner. Since the air conditioner forcibly takes in the air in the room, the ratio of taking in the dirt in the air is high. The taken-in air is heated, cooled, or dehumidified by an internal heat exchanger and discharged from the air conditioner into the room. When the air conditioner is used for a long period of time, dirt in the room enters the inside of the air conditioner together with the air and adheres to the inside of the air conditioner. Our analysis showed that the main stains were dust and oil. These are attached to the inner surface of the housing of the air conditioner, the tubular blower fan, the filter, the ramp, and the like. In particular, it tends to adhere significantly to the surface of resin parts.

Regarding oil stains, Patent Document 1 describes a fluorine-containing copolymer that suppresses the adhesion of oil stains by coating the surface of the base material. According to the present invention, the surface of a base material is coated with a fluororesin having a small surface energy to suppress the adhesion of oil stains.

As for dust, the greater the resistance on the surface, the easier it is for electrostatic adhesion. Therefore, Patent Document 2 describes an invention in which the resin surface is coated with a low-resistance film to suppress the adhesion of dust.

Japanese Unexamined Patent Publication No. 2001-163927 Japanese Unexamined Patent Publication No. 2012-236941

The coating film of the above patent document has an effect of suppressing adhesion to oil mist or dust. However, it is not a coat film that has the effect of suppressing the adhesion of both oil mist and dust.

Various fluororesins with high liquid repellency described in Patent Document 1, for example, polytetrafluoroethylene, polyvinyl fluoride, etc., have a surface resistance of about 10 ¹⁸ Ω / □, which is a widely used acrylic resin. , Polycarbonate resin, etc., ^{higher than 10 16} Ω / □. Therefore, the surface is easily charged and dust is easily attached.

On the other hand, the coating film described in Patent Document 2 has a surface resistance of ^{108 to 10} Ω / □, which is considerably smaller than that of a general-purpose resin, although the surface resistance varies depending on the relative humidity of the environment in which the resin is placed. Therefore, dust does not easily adhere. However, the contact angle with water is 10 ° or less, and it is easy for the liquid to adhere. Therefore, there is a problem that oil mist easily adheres.

From the above, in order to suppress the adhesion of both oil mist and dust, a coating film having high liquid repellency and low surface resistance is required.

As a result of diligent studies, we applied an alcohol solution (coating solution) containing a fluorine-containing organic compound, silicon dioxide particles, and a carboxy group-containing resin having a glass transition temperature of 60 ° C. or higher to various substrates and dried them. It has been found that the coat film formed by the above-mentioned coating film exhibits high liquid repellency and low surface resistance, and has reached the present invention. The carboxy group-containing resin has sufficient water resistance for practical use, and styrene / (meth) acrylic having a glass transition temperature of 60 ° C. or higher so as not to cause deformation at the expected maximum temperature inside the housing of the home appliance. It is preferable to use an acid copolymer.

Further, since the coating liquid of the present invention is an alcohol rather than a ketone or ester solvent, it is an acrylonitrile-butadiene-styrene copolymer (ABS resin) that is often used in housings of home appliances such as air conditioners and televisions. ), Acrylic resin, polycarbonate resin, and other various resins are not dissolved, so that the coating film of the present invention can be formed on a large number of resin substrates by coating.

The specific solution is as follows.
(1)
A coating liquid containing at least a fluorine-containing organic compound, silicon dioxide particles, a carboxy group-containing resin having a glass transition temperature of 60 ° C. or higher, and a solvent, wherein the solvent contains an alcohol having a boiling point of 100 ° C. or lower.
(2)
The coating liquid according to (1), wherein the carboxy group-containing resin is a styrene / (meth) acrylic acid copolymer.
(3)
The coating liquid according to (2), wherein the styrene / (meth) acrylic acid copolymer has an acid value of 160 or more.
(4)
The coating liquid according to any one of (1) to (3), wherein the silicon dioxide particles have an average particle diameter of 10 to 40 nm.
(5)
The coating liquid according to any one of (1) to (3), wherein the silicon dioxide particles are amorphous and have a short side of 10 to 20 nm and a long side of 50 to 100 nm.
(6)
The content ratio of the silicon dioxide particles in the coating liquid is 20 to 80% by mass with respect to the total amount of the carboxy group-containing resin and the silicon dioxide particles, according to any one of (1) to (5). Coating liquid.
(7)
The coating liquid according to any one of (1) to (6), wherein the content ratio of the fluorine-containing organic compound in the coating liquid is 0.5 to 2.5% by mass.
(8)
The fluorine-containing organic compound according to any one of (1) to (7), wherein the main chain is a hydrocarbon chain and a benzene ring having a fluorine-containing group is bonded to the hydrocarbon chain. Coating liquid.
(9)
The coating liquid according to (8), wherein the fluorine-containing group is a fluoroalkyl group.
(10)
The coating liquid according to any one of (1) to (9), further containing a pyridinium salt.
(11)
A coating film containing at least a fluorine-containing organic compound, silicon dioxide particles, and a carboxy group-containing resin having a glass transition temperature of 60 ° C. or higher.
(12)
The coat film according to (11), wherein the carboxy group-containing resin is a styrene / (meth) acrylic acid copolymer.
(13)
The coat film according to (12), wherein the styrene / (meth) acrylic acid copolymer has an acid value of 160 or more.
(14)
The coat film according to any one of (11) to (13), wherein the silicon dioxide particles have an average particle diameter of 10 to 40 nm.
(15)
The coat film according to any one of (11) to (13), wherein the silicon dioxide particles are amorphous and have a short side of 10 to 20 nm and a long side of 50 to 100 nm.
(16)
The content ratio of the silicon dioxide particles in the coating film is 20 to 80% by mass with respect to the total amount of the carboxy group-containing resin and the silicon dioxide particles, according to any one of (11) to (15). Coat film.
(17)
The coat film according to any one of (11) to (16), wherein the content ratio of the fluorine-containing organic compound in the coat film is 5 to 40% by mass.
(18)
The fluorine-containing organic compound according to any one of (11) to (17), wherein the main chain is a hydrocarbon chain and a benzene ring having a fluorine-containing group is bonded to the hydrocarbon chain. Coat film.
(19)
The coat film according to (18), wherein the fluorine-containing group is a fluoroalkyl group.
(20)
The coat film according to any one of (11) to (19), further containing a pyridinium salt.
(21)
The coat film according to any one of (11) to (20), which has an average film thickness of 0.8 μm or more.
(22)
The coat film according to any one of (11) to (21), wherein the arithmetic mean roughness of the film surface is 0.1 μm or less.
(23)
A base material having the coating film according to any one of (11) to (22) on a part or the entire surface of the base material.
(24)
At least a heat exchanger, a blower fan for passing air through the heat exchanger, a wind direction plate for adjusting the direction of air emitted from the heat exchanger, and a housing containing the heat exchanger and the blower fan inside. Is an air conditioner that includes
An air conditioner having the coating film according to any one of (11) to (22) on the surface of at least one component selected from the group consisting of the blower fan, the wind direction plate, and the housing.

According to the coating liquid of the present invention, it is possible to form a highly liquid-repellent and low-surface resistance coating film that does not easily adhere oil mist and dust to the surface of many base materials. Further, since the main solvent in the coating liquid is alcohol, the coating film is also applied and dried on the surface of parts made of ABS resin, acrylic resin, polycarbonate resin, etc., which are soluble in ketone or ester solvents. Can be formed. In the present invention, an alcohol having a boiling point of 100 ° C. or lower at normal pressure is used as the main solvent so that the solvent can be quickly dried during film formation.

It is a schematic diagram of the cross section of the base material which has the coating film of this invention. It is a schematic diagram of the cross section of the air conditioner of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.

FIG. 1 is a schematic cross-sectional view of a base material having a coating film of the present invention. A coat film 2 is formed on the base material 1. The coat film 2 contains silicon dioxide particles 3 and a mixture 4 of a carboxy group-containing resin and a fluorine-containing organic compound. The coating liquid comprises a liquid in which these materials are dissolved or dispersed in an alcohol having a boiling point of 100 ° C. or lower at normal pressure.

Hereinafter, the coating liquid, the coating film, and the air conditioner will be described.
<Coating liquid>
1. 1. Fluorine-containing organic compound The fluorine-containing organic compound used in the present invention is added to impart liquid repellency to the coat film. The fluorine-containing organic compound is not particularly limited as long as it is soluble in an alcohol having a boiling point of 100 ° C. or lower, but the following two categories of compounds are preferable.

(1) Compound having a carboxy group or a sulfonic acid group in the side chain The fluorine-containing organic compound used in the present invention has a hydrocarbon chain as the main chain and a hydrocarbon group (a fluorine-containing functional group) in the hydrocarbon chain. , And a compound to which a carboxy group is bonded are suitable. The fluorine-containing organic compound having the chemical structure is represented by, for example, the following compound A group.

By having a hydrophilic carboxy group, the polarity as a compound is increased and it becomes easy to dissolve in alcohol. In addition, it has a chemical structure that also has a fluorine-containing group for imparting liquid repellency. The compounds of the compound A group can be synthesized by a radical reaction using the compound A1 group and the compound A2.

As a more specific example of the chemical structure of the compound A group, the following compounds of the compounds 1 to 4 can be mentioned.

By the way, a compound having a sulfonic acid group, which is a hydrophilic substituent other than the carboxy group of the compound A group, also has good solubility in alcohol, and the coat film formed by the coating can exhibit liquid repellency. The fluorine-containing organic compound having the chemical structure is represented by, for example, the following compound group B.

By having a hydrophilic sulfonic acid group, the polarity as a compound is increased and it becomes easy to dissolve in alcohol. In addition, it has a chemical structure that also has a fluorine-containing group for imparting liquid repellency. The compounds of the compound B group can be synthesized by a radical reaction using the compound A1 group and the compound B2.

Specific examples of the chemical structure of the compound B group include the following compounds in the 5th to 8th groups.

(2) Compound having a benzene ring on the side chain The fluorine-containing organic compound used in the present invention has a hydrocarbon chain as the main chain and a benzene ring having a fluorine-containing group (a fluorine-containing functional group) on the hydrocarbon chain. A compound to which is bound is preferable. The reason is that the benzene ring, which has a large steric hindrance, hinders the alignment of the hydrocarbon chains and becomes amorphous, which improves the flatness of the formed coat film and provides a gap between the hydrocarbon chains for coating. This is because the solubility of the fluorine-containing organic compound in the solvent is improved by making it easier for the alcohol contained in the liquid to enter. The fluorine-containing organic compound having the chemical structure is represented by, for example, the following compound C group.

The compounds of the compound C group can be synthesized by a radical reaction using the compound C1 group.

As a more specific example of the chemical structure of the compound C group, the following compounds of the 9th to 12th groups can be mentioned.

The fluorine-containing organic compound used in the present invention may be a compound having a chemical structure other than these as long as it is soluble in an alcohol having a boiling point of 100 ° C. or lower. The compounds 1 to 8 have a structure in which the hydrocarbon chain has no hydrogen atom as a liquid-repellent group or a fluoroalkyl chain having one, two, or four hydrogen atoms is bonded. Here, x and y indicating the length of the hydrocarbon chain are not particularly limited.

The larger the number of carbon atoms in the fluoroalkyl chain, the higher the liquid repellency. As a result of the examination, n must be 3 or more in order to make the contact angle of the formed coat film with water 100 ° or more. On the other hand, when n exceeds 8, the solubility in alcohol becomes low, and a phenomenon is observed in which the coating liquid is partially separated in the coating liquid and the coating liquid becomes turbid. Therefore, the suitable upper limit of n is determined to be 8. Even if n exceeds 8, it is possible to stir the coating liquid before coating, but if n is 8 or less, it is originally dissolved in the coating liquid, so it is necessary to give vibration such as stirring. Absent.

Compounds 9 to 12 have a chemical structure in which a benzene ring is bonded to a hydrocarbon chain. The benzene ring has, as a liquid-repellent group, a fluoroalkyl chain having no hydrogen atom or having one, two, or four hydrogen atoms. Here, x and y indicating the length of the hydrocarbon chain are not particularly limited.

The larger the number of carbon atoms in the fluoroalkyl chain, the higher the liquid repellency. As a result of the examination, n must be 3 or more in order to make the contact angle of the formed coat film with water 100 ° or more. On the other hand, when n exceeds 8, the solubility in alcohol becomes low, and a phenomenon is observed in which the coating liquid is partially separated in the coating liquid and the coating liquid becomes turbid. Therefore, the suitable upper limit of n is determined to be 8. Even if n exceeds 8, it is possible to stir the coating liquid before coating, but if n is 8 or less, it is originally dissolved in the coating liquid, so it is necessary to give vibration such as stirring. Absent.

The content ratio of the fluorine-containing organic compound in the coating liquid is not particularly limited, but is preferably 5% by mass or more, more preferably 15% by mass, from the viewpoint of obtaining a coating film having high liquid repellency with respect to all components other than the solvent. % Or more, more preferably 25% by mass or more, preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 30% by mass or less, from the viewpoint of ensuring the physical strength of the coated film to be formed. is there.

2. Silicon dioxide particles The silicon dioxide particles used in the present invention are added to reduce the surface resistance of the coating film. Since the surface resistance of the silicon dioxide particles is lower than that of the binder resin used for the coating liquid, increasing the addition rate lowers the surface resistance of the coating film and improves the dust resistance.

(1) Particle size The smaller the average particle size of the silicon dioxide particles, the larger the surface area per unit mass, and the easier it is to reduce the surface resistance of the coat film. Further, it was found that when the coating liquid prepared by using the silicon dioxide particles having an average particle diameter of more than 40 nm was allowed to stand, the silicon dioxide particles were precipitated in about one month. Specifically, when a coating liquid prepared using silicon dioxide particles having an average particle diameter of 50 nm or 70 nm was allowed to stand, precipitation occurred in about one month. However, when the coating liquid prepared by using the silicon dioxide particles having an average particle diameter of 40 nm was allowed to stand, no precipitation occurred even after one month. Therefore, the average particle size of the silicon dioxide particles is preferably 40 nm or less. However, if the average particle size is too small, the proportion of particles that do not enter the container and fly into the air during weighing at the time of preparing the coating liquid increases. Therefore, when the shape of the silicon dioxide particles is spherical (including substantially spherical), the average particle size is preferably 10 to 40 nm in consideration of handleability at the time of preparing the coating liquid. Here, the average particle size is a value measured by the dynamic light scattering method.

(2) Shape As for the shape of the silicon dioxide particles, the irregular shape has a larger surface area per unit weight than the spherical shape, so that the surface resistance of the coat film can be easily lowered, which is preferable. The smaller the particle size, the larger the surface area per unit mass, which is preferable. However, in the case of amorphous particles, the short side is 10 in consideration of handleability at the time of preparing the coating liquid, as in the case of spherical particles. It is preferably about 20 nm and the long side is preferably 50 to 100 nm. Here, the measurement of the short side and the long side of the amorphous particle is a value obtained from an electron micrograph of the particle.

The content ratio of the silicon dioxide particles in the coating liquid is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, from the viewpoint of obtaining a coating film having low surface resistance with respect to all the components other than the solvent. It is more preferably 35% by mass or more, preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, from the viewpoint of ensuring the physical strength of the coated film to be formed.

The content ratio of the silicon dioxide particles in the coating liquid is preferably 20% by mass or more from the viewpoint of obtaining a coating film having high liquid repellency and low surface resistance with respect to the total amount of the carboxy group-containing resin and the silicon dioxide particles. , More preferably 25% by mass or more, further preferably 30% by mass or more, and from the viewpoint of the physical strength of the coating film, preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass. It is as follows.

3. 3. Carboxy group-containing resin The carboxy group-containing resin used in the present invention is not particularly limited as long as it has a glass transition temperature of 60 ° C. or higher and is soluble in alcohol having a boiling point of 100 ° C. or lower. For example, (meth) acrylic. / (Meta) acrylic acid resin, styrene / (meth) acrylic acid copolymer, polyvinyl butyral resin having a hydroxyl group and the like can be mentioned. The (meth) acrylic acid means acrylic acid, methacrylic acid, or a mixture thereof. The same applies to (meth) acrylic. As a result of examining these resins, it was found that the surface resistance of the coating film containing the styrene / (meth) acrylic acid copolymer was smaller than that when other resins were used. Therefore, the carboxy group-containing resin is preferably a styrene / (meth) acrylic acid copolymer. In particular, the resin having a higher acid value tended to have a lower surface resistance. In addition, the resin having a higher acid value had higher solubility in alcohol. In particular, a resin having an acid value of 160 or more is suitable because it dissolves in alcohol in a short stirring time. The acid value of the resin is more preferably 200 or more, still more preferably 230 or more.

The content ratio of the carboxy group-containing resin in the coating liquid is not particularly limited, but is preferably 25% by mass or more from the viewpoint of obtaining a coating film having high liquid repellency and low surface resistance with respect to all components other than the solvent. , More preferably 30% by mass or more, further preferably 40% by mass or more, and from the viewpoint of solubility in alcohol or the like, preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 55% by mass. It is as follows.

4. Solvent As described above, in the present invention, an alcohol having a boiling point of 100 ° C. or lower at normal pressure is used as the solvent. Specific examples of the alcohol include methanol (boiling point: about 65 ° C.), ethanol (boiling point: about 78 ° C.), 1-propanol (boiling point: about 97 ° C.), 2-propanol (boiling point: about 82 ° C.). Examples thereof include 2-butanol (boiling point: about 98 ° C.) and 2-methyl-2-propanol (boiling point: about 82 ° C.). These alcohols are preferable because they are dried and cured in a relatively short time by applying the coating liquid to the base material and then leaving it to stand. An alcohol having a boiling point of more than 100 ° C. at normal pressure may be used in combination as long as the effect of the present invention is not impaired.

As described above, the ketone solvents such as acetone and 2-butanone and the ester solvents such as ethyl acetate and butyl acetate are ABS resins, acrylic resins, and polycarbonate resins used for housings of home appliances and various parts. It is not preferable as a solvent for the coating liquid because it dissolves resins such as the above, but it may be used as long as the above problems do not occur.

5. Other Additives Examples of additives other than the essential components include cross-linking agents added to increase the strength of the coat film, antibacterial agents that enhance the antibacterial properties of the coat film, and the like.

(A) Cross-linking agent Examples of the cross-linking agent include compounds having an alkoxysilyl group capable of cross-linking with a carboxy group or a hydroxyl group in the resin. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glusidoxypropyltrimethoxysilane, 3-glusidoxypropyltriethoxysilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, etc. Can be mentioned.

Further, a compound having an alkoxytitanium group can be mentioned. Specific examples thereof include titanium acetylacetate, titanium tetraacetylacetone, titanium ethylacetate acetate, titanium octylene glycolate, and titanium ethylacetate acetate.

By adding these cross-linking agents, there is an advantage that cross-linking between the resins occurs and the physical strength of the coating film is improved.

(B) Antibacterial agent The antibacterial agent is preferably one that is soluble in alcohol, and examples thereof include a pyridinium salt. Examples of the pyridinium salt include hexylpyridinium chloride, octylpyridinium chloride, decylpyridinium chloride, dodecylpyridinium chloride, cetylpyridinium chloride, hexylpyridinium bromide, octylpyridinium bromide, decylpyridinium bromide, dodecylpyridinium bromide, and cetylpyridinium bromide. Be done. These show a strong bactericidal action against gram-positive bacteria such as staphylococci and fungi such as mold.

In addition, antibacterial agents such as hinokitiol and 2-furfural aldehyde (commonly known as furfural), which are soluble in alcohol, can also be used.

By adding these to the coating liquid, it is possible to suppress the growth of bacteria such as mold slightly adhering inside the air conditioner on which the coating film is formed, and to suppress the generation of foul odors and the like.

The content ratio of the antibacterial agent in the coating liquid is not particularly limited, but is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and further preferably 2.0% by mass with respect to all the components other than the solvent. % Or more, preferably 10.0% by mass or less, more preferably 7.0% by mass or less, still more preferably 5.0% by mass or less.

<Coat film>
The coating film of the present invention can be formed by applying the coating liquid to the surface of a base material (part), drying and curing the coating film. When forming the coating film on the substrate, various wet coating methods can be used. Specific examples thereof include a dip coat, a spin coat, a flow coat, a bar coat, and a spray coat. Any of these coating methods can be used when the shape of the base material is flat, but spray coating is preferable when the base material has various irregularities.

When the base material is a resin, if the film thickness of the coating film is too thin, even if the surface resistance of the coating film is small, if the surface resistance of the base material is large, dust is likely to be attached due to the influence of the surface resistance of the base material. .. Therefore, the average film thickness of the coat film is preferably 0.8 μm or more, more preferably 2 μm or more. When the average film thickness of the coating film is 2 μm or more, the influence of the surface resistance of the base material hardly occurs.

The smaller the surface roughness of the coat film, the more the adhesion of oil mist and the like can be suppressed. Therefore, the arithmetic mean roughness of the surface of the coat film is preferably 0.1 μm or less. It should be noted that the surface of the coat film may have a sea-island structure when the alcohol as a solvent volatilizes, probably because a fluorine-containing organic compound, silicon dioxide particles, or the like is added. In that case, the size of the sea-island structure can be reduced and the surface unevenness can be reduced by increasing the drying temperature and the volatilization rate.

<Air conditioner>
FIG. 2 is a schematic cross-sectional view of the air conditioner of the present invention. The air conditioner of the present invention is, for example, a housing 5, a heat exchanger 6 for controlling the temperature and humidity of the air inside the housing, and an air blower for taking in indoor air inside the housing and blowing it outside the housing. The temperature and humidity were controlled by a fan 7, an air suction port 8 that takes in indoor air, a filter 9 for removing dust in the taken air, a dew pan 10 that receives water droplets generated from the heat exchanger, and a heat exchanger. It is composed of horizontal blades 11 and the like for controlling the direction when air is discharged to the outside of the housing.

Since the housing 5, the blower fan 7, the filter 9, the horizontal blade 11, and the like are made of a resin such as ABS resin, acrylic resin, and polycarbonate resin, the surface resistance of these parts is about 10 ¹⁶ Ω / □. .. The contact angle with water is about 80 to 95 °. By forming the coating film of the present invention on the surface of these parts, the surface resistance is ^{reduced to about 10 10} Ω / □ or less, and the contact angle with water becomes 100 ° or more, so that dust, oil mist, etc. are removed from the parts. It becomes difficult to adhere to. As a result, an increase in ventilation resistance inside the air conditioner can be suppressed, and the generation of offensive odors derived from bacteria that grow on the adhered portion of dust, oil mist, etc. can also be suppressed.

Hereinafter, the present invention will be specifically described based on examples.

Example 1
(1) Preparation of coating liquid Compound 13 (2 parts by mass) having n of 8 in the compound 3 group as a fluorine-containing organic compound, silicon dioxide particles having an average particle diameter of 10 nm (5 parts by mass), and Table 1 as a resin. The various resins shown (5 parts by mass) were added to ethanol (88 parts by mass), and the mixture was stirred and dissolved with an overhead stirrer to prepare a coating liquid.

(2) Formation of Coat Film A coat film was formed by applying each of the prepared coating liquids to an ABS resin plate having a thickness of 2 mm with a bar coater and then leaving it in a constant temperature bath at 60 ° C. for about 1 hour. The number of bar coaters used for coating was selected so that the average film thickness of the coating film was about 8 to 10 μm.

(3) Evaluation (a) Surface resistance The surface resistance of the coated film was measured using a surface resistance meter hiresta-UP manufactured by Mitsubishi Chemical Analytical Corporation. The voltage at the time of measurement is 100V.
(B) Contact angle The contact angle of the surface of the coating film with water was measured using a contact angle meter CAD-1 manufactured by Kyowa Interface Science Co., Ltd.
(C) Evaluation of Dust Adhesion Rate With the coat film surface facing up, tobacco ash was poured onto the coat film surface as a simulated dust. Then, the ABS resin plate was lightly struck on the floor twice with the coated film surface vertical. At that time, the ratio of tobacco ash remaining attached to the surface of the coating film was investigated and evaluated according to the following criteria. It can be judged that the smaller the proportion of ash remaining on the surface of the coat film, the more the dust adhesion is suppressed.
a: Tobacco ash adhesion rate is less than 10% b: Tobacco ash adhesion rate is 10% or more

(4) Evaluation results Table 1 shows the evaluation results.

All of the coated films 1 to 8 showed high liquid repellency having a contact angle with water of 100 ° or more. Looking at the adhesion ratio of tobacco ash, the adhesion ratio of tobacco ash was less than 10% in the coat films 1 to 4, but the adhesion ratio of tobacco ash was 10% in the coat films 5 to 8. As mentioned above, in particular, the coat films 7 and 8 were attached to about half. From the above, it was found that the adhesion of dust was suppressed by using the styrene / acrylic acid resin as the resin. Looking at the adhesion ratio of tobacco ash and the surface resistance of the coating film, when the surface resistance was low, specifically, when it was 2 × 10 ¹¹ Ω / □ or less, the adhesion ratio of tobacco ash was less than 10%. .. That is, it is judged that the lower the surface resistance, the more the adhesion of dust is suppressed. It was found that the acid values of the resins used in the coat films 1 and 2 were 150 and 160, respectively, and the surface resistance could be reduced to about 1/10 even if the acid value was 10 higher. Therefore, it can be seen that the acid value of the styrene / acrylic acid resin used is preferably 160 or more.

Example 2
A coating film was used in the same manner as in Example 1 except that the silicon dioxide particles having the average particle size and shape shown in Table 2 were used and the resin was unified to a styrene / acrylic acid resin having an acid value of 240 and a weight average molecular weight of 17,000. Was formed on the ABS plate. Then, the coat film was evaluated by the same method as in Example 1. The evaluation results are shown in Table 2.

The surface resistance of the coating film tended to increase as the average particle size increased. The coat films 9 to 12 using silicon dioxide particles having a spherical shape and an average particle size of 10 to 40 nm had a tobacco ash adhesion ratio of less than 10%. The maximum surface resistance was 5 × 10 ¹⁰ Ω / □. The coat films 13 and 14 using silicon dioxide particles having an average particle size of 50 to 70 nm had a tobacco ash adhesion ratio of 10% or more and a minimum surface resistance of 1 × 10 ¹¹ Ω / □. .. Therefore, it was found that when the shape is spherical, the average particle size of the silicon dioxide particles used is preferably 10 to 40 nm. When the shape is irregular, the coating films 15 and 16 using silicon dioxide having an average short side of 10 to 20 nm and an average long side of 50 to 100 nm have a tobacco ash adhesion ratio of less than 10% and surface resistance. Was 8 × 10 ¹⁰ Ω / □ at the maximum. The coating film 17 using silicon dioxide having an average short side of 30 nm and an average long side of 150 nm had a tobacco ash adhesion ratio of 10% or more and a surface resistance of 2 × 10 ¹¹ Ω / □. Therefore, it was found that when the shape is irregular, the silicon dioxide particles used are preferably those having an average short side of 10 to 20 nm and an average long side of 50 to 100 nm.

Example 3
In addition to compound 13, compound 14 (2 parts by mass) having n of 3 in the compound 3 group, compound 15 (2 parts by mass) having n of 8 in the compound 4 group, and compound 4 as fluorine-containing organic compounds. Among them, compound 16 (2 parts by mass) having n of 3, compound 17 (2 parts by mass) having n of 8 in the compound 6 group, and compound 18 (2 parts by mass) having n of 8 in the compound 10 group. Compound 19 (2 parts by mass) having n of 3 in the compound 10 group and compound 20 (2 parts by mass) having n of 8 in the compound 12 group were used, and the resin had an acid value of 240 and a weight average molecular weight of 17, respectively. A coat film was formed on the ABS plate in the same manner as in Example 1 except that the styrene / acrylic acid resin was unified to 000. Then, the coat film was evaluated by the same method as in Example 1. The evaluation results are shown in Table 3.

The contact angle of each of the coated films was 100 ° or more, the adhesion rate of tobacco ash was less than 10%, and the surface resistance was 3 × 10 ⁹ Ω / □ at the maximum. Therefore, it was found that the coat film using the fluorine-containing organic compound of the present invention has excellent antifouling properties. The larger n indicating the length of the fluoroalkyl group in the fluorine-containing organic compound tended to have a larger contact angle, and the surface resistance tended to be higher.

Example 4
When preparing the coating liquid, the antifouling property was investigated when the addition ratios of the resin and the silicon dioxide particles were variously changed. Specifically, when preparing the coating liquid shown in Example 1, the amount of silicon dioxide particles added was changed to 0 to 9 parts by mass, and the amount of resin added was changed to 10 to 1 part by mass. That is, in each of the coating liquids, the total amount of the silicon dioxide particles and the resin added was 10 parts by mass. Other than that, the same raw material as in Example 1 was added in the same amount to prepare a coating liquid, and a coating film was formed on an ABS plate using the prepared coating liquid. Then, the coat film was evaluated by the same method as in Example 1. The evaluation results are shown in Table 4.

The coat film 26 to which the silicon dioxide particles are not added and the coat film 27 containing 10% by mass of the silicon dioxide particles with respect to the total amount of the resin and the silicon dioxide particles have a tobacco ash adhesion ratio of 10% or more. Met. The surface resistance was 1 × 10 ¹¹ Ω / □ or more. The coating films 28 to 35 containing 20% by mass or more of the silicon dioxide particles with respect to the total amount of the resin and the silicon dioxide particles had an adhesion ratio of tobacco ash of less than 10%. The surface resistance was 3 × 10 ¹⁰ Ω / □ or less. Therefore, it was found that the composition of the coat film is preferably 20% by mass or more of the silicon dioxide particles with respect to the total amount of the resin and the silicon dioxide particles. By the way, the coat film 35 containing 90% by mass of silicon dioxide particles with respect to the total amount of the resin and the silicon dioxide particles has low physical strength, and when the surface of the coat film is rubbed with a tissue paper under a load of about 100 g. , It turned out to be easily peeled off. No peeling was observed in the coated films 28 to 34. It is considered that the decrease in the physical strength of the coat film 35 was caused by the small proportion of the resin added to retain the film material and to increase the physical strength of the film. Since the physical strength of the coat film, which is practically sufficient, cannot be maintained unless the ratio of the resin in the coat film is increased to some extent, the content ratio of the resin is 20% by mass or more with respect to the total amount of the resin and the silicon dioxide particles. It is considered preferable. In other words, the content ratio of the silicon dioxide particles is preferably 80% by mass or less with respect to the total amount of the resin and the silicon dioxide particles. Therefore, it was found that the composition of the coat film is preferably 20 to 80% by mass of the silicon dioxide particles with respect to the total amount of the resin and the silicon dioxide particles.

The coating liquid of the present invention is useful for forming a coating film that makes it difficult for oil stains, dust, etc. to adhere to the surface. The coat film of the present invention is provided, for example, inside the housing of an air conditioner, the surface of a blower fan, the surface of a filter, and the like.

1: Base material 2: Coat film 3: Silicon dioxide particles 4: Mixture of carboxy group-containing resin and fluorine-containing organic compound 5: Housing 6: Heat exchanger 7: Blower fan 8: Air suction port 9: Filter 10: Dew Sauce
11: Horizontal blade

Claims (16)

It contains at least a fluorine-containing organic compound, silicon dioxide particles, a carboxy group-containing resin having a glass transition temperature of 60 ° C. or higher, and a solvent.
The fluorine-containing organic compound has (1) a compound in which the main chain is a hydrocarbon chain and a fluorine-containing group and a carboxy group bonded to the hydrocarbon chain, and (2) the main chain is a hydrocarbon chain. It is one or more selected from the group consisting of compounds in which a benzene ring having a fluorine-containing group is bonded to a hydrocarbon chain.
The silicon dioxide particles have an average particle diameter of 10 to 40 nm or an amorphous shape, and have a short side of 10 to 20 nm and a long side of 50 to 100 nm.
The carboxy group-containing resin is a styrene / (meth) acrylic acid copolymer.
The solvent is a coating liquid containing alcohol having a boiling point of 100 ° C. or lower. The coating liquid according to claim 1 , wherein the styrene / (meth) acrylic acid copolymer has an acid value of 160 or more. The coating liquid according to claim 1 or 2 , wherein the content ratio of the silicon dioxide particles in the coating liquid is 20 to 80% by mass with respect to the total amount of the carboxy group-containing resin and the silicon dioxide particles. The coating liquid according to any one of claims 1 to 3 , wherein the content ratio of the fluorine-containing organic compound in the coating liquid is 0.5 to 2.5% by mass. The coating liquid according to any one of claims 1 to 4, wherein the fluorine-containing group is a fluoroalkyl group. The coating liquid according to any one of claims 1 to 5 , further comprising a pyridinium salt. At least a fluorine-containing organic compound, see-containing silicon dioxide particles, and the glass transition temperature of the 60 ° C. or more carboxy group-containing resin,
The fluorine-containing organic compound has (1) a compound in which the main chain is a hydrocarbon chain and a fluorine-containing group and a carboxy group bonded to the hydrocarbon chain, and (2) the main chain is a hydrocarbon chain. One or more selected from the group consisting of compounds in which a benzene ring having a fluorine-containing group is bonded to a hydrocarbon chain.
The silicon dioxide particles have an average particle diameter of 10 to 40 nm or an amorphous shape, and have a short side of 10 to 20 nm and a long side of 50 to 100 nm.
The carboxy group-containing resin is a coat film which is a styrene / (meth) acrylic acid copolymer. The coat film according to claim 7 , wherein the styrene / (meth) acrylic acid copolymer has an acid value of 160 or more. The coat film according to claim 7 or 8 , wherein the content ratio of the silicon dioxide particles in the coat film is 20 to 80% by mass with respect to the total amount of the carboxy group-containing resin and the silicon dioxide particles. The coat film according to any one of claims 7 to 9 , wherein the content ratio of the fluorine-containing organic compound in the coat film is 5 to 40% by mass. The coat film according to any one of claims 7 to 10, wherein the fluorine-containing group is a fluoroalkyl group. The coat film according to any one of claims 7 to 11 , further containing a pyridinium salt. The coat film according to any one of claims 7 to 12 , wherein the average film thickness is 0.8 μm or more. The coat film according to any one of claims 7 to 13 , wherein the arithmetic mean roughness of the film surface is 0.1 μm or less. A base material having the coating film according to any one of claims 7 to 14 on a part or the entire surface of the base material. At least a heat exchanger, a blower fan for passing air through the heat exchanger, a wind direction plate for adjusting the direction of air emitted from the heat exchanger, and a housing containing the heat exchanger and the blower fan inside. Is an air conditioner that includes
An air conditioner having a coating film according to any one of claims 7 to 14 on the surface of at least one component selected from the group consisting of the blower fan, the wind direction plate, and the housing.

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