JP5537759B2 - Heat-reflective coating composition and coated article - Google Patents

Description

  The present invention relates to a heat ray highly reflective coating composition that can be applied to roofs, rooftops and outer walls of buildings, vehicles, ships, plants, storerooms, roads, and the like, and a coated article having a coating film of this composition.

In general, dark color paints containing black pigments are often used on the roofs of buildings. However, dark color paints generally have a problem that they easily absorb solar energy, raise the temperature of buildings and the like, and increase energy consumption for air conditioning.
On the other hand, although white-colored coating films can be expected to be highly reflective of heat rays, they have problems such as a landscape-like problem in which contamination is conspicuous and a decrease in heat ray reflection due to contamination.

In order to solve this problem, Patent Documents 1 and 2 disclose a paint composition colored in black, which is an achromatic color, by mixing chromatic pigments of red, orange, yellow, green, blue, and purple. Proposed. However, it is difficult to adjust the color tone, and the color pigment is deteriorated by ultraviolet rays, so that there is a problem that the color is easily changed.
Further, as an example using a heat ray high reflection pigment, Patent Document 3 proposes a black fired pigment coating composition having a high solar radiation reflectance in the near infrared region. However, since chromium-based pigments are used, there is a problem that the health of workers during painting work is impaired and the environment is polluted.
Further, as dark-colored heat ray high reflection pigments, pigments containing bismuth manganese oxide (Patent Document 4) and pigments containing rare earth manganese oxide (Patent Document 5) have been proposed.
Japanese Patent No. 2593968 JP-A-5-293434 Japanese Patent No. 3468698 JP-T-2002-532379 JP 2002-38048 A

In consideration of the effects on the health and environment of workers, the present inventors have used a complex metal oxide containing a Bi and / or Y oxide and a Mn oxide as a dark-colored heat ray highly reflective pigment. We considered using pigments.
However, it has been found that the coating film using the composite metal oxide pigment has a problem that the reflective performance of the heat ray is lowered with time.
The present invention has been made in view of the above circumstances, and includes a composite metal oxide pigment containing an oxide of Bi and / or Y and an oxide of Mn, hardly contaminating, and heat ray reflection performance. It is an object of the present invention to provide a heat ray highly reflective coating composition that can stably maintain a coating, and a coated article having a coating film of this composition.

The present invention employs the following configuration.
[1] A composite metal oxide pigment containing an oxide of Bi and / or Y and an oxide of Mn, and a general formula Si (OR) ₄ (wherein R may be the same as or different from each other; A heat ray highly reflective coating composition comprising a compound represented by (2) or a partial condensate thereof and a resin , wherein a part or all of the resin is a fluororesin .
[2] The heat ray highly reflective coating composition according to [1], wherein the content of the composite metal oxide pigment is 0.1% by mass or more.
[3] The heat ray highly reflective coating composition according to [1] or [2] , further containing a curing agent.
[4] A coated article comprising a coating film formed by coating the heat ray high reflection coating composition according to any one of [1] to [3] .

  The heat ray highly reflective coating composition and coated article of the present invention are less likely to be contaminated and can stably maintain the heat ray reflection performance.

[Heat ray highly reflective coating composition]
The heat ray highly reflective coating composition of the present invention (hereinafter referred to as “the present coating composition”) is a composite metal oxide pigment (hereinafter referred to as “composite pigment M”) containing an oxide of Bi and / or Y and an oxide of Mn. And a compound represented by the general formula Si (OR) ₄ (wherein R may be the same as or different from each other and represent an alkyl group having 1 to 2 carbon atoms) or a partial condensate thereof (hereinafter referred to as “a”). "Compound A") and a resin, and a part or all of the resin is a fluororesin .

(Pigment)
The composite pigment M contains an oxide of Bi and / or Y and an oxide of Mn. The content of manganese in the composite pigment M is preferably 5 to 65% by mass, and more preferably 10 to 50% by mass. If the manganese content is low, the heat reflection effect may not be sufficiently obtained.
As the composite pigment M, it is preferable to use a mixture obtained by baking a mixture of Bi and / or Y and Mn at a baking temperature of 700 ° C. or higher. The average particle size of the composite pigment M is preferably 0.1 μm to 30 μm. If the average particle size is too large, the gloss may be lowered. Examples of commercially available products that satisfy these preferable conditions include Asahi Kasei Kogyo Co., Ltd. Black 6303, Black 6301, and the like.

The composite pigment M is a black-colored pigment, and can be dispersed and blended in the resin.
The content of the composite pigment M with respect to the resin solid content is preferably 0.1 to 200% by mass, and 10 to 100% by mass when only the composite pigment M is used as the pigment in the coating composition. Is more preferable. When the content of the composite pigment M is small, the heat reflection effect cannot be sufficiently obtained. On the other hand, when there is too much content, there exists a possibility that glossiness may fall.

The coating composition may contain other color pigments in order to adjust the color tone according to the application and purpose. For example, inorganic pigments such as titanium oxide, bengara, ocher, calcium carbonate, aluminum silicate, white carbon, fine powder silicic acid, and organic pigments such as phthalocyanine blue, phthalocyanine green, quinacridone, isoindolinone, benzimidazolone, dioxazine, etc. Can be used.
However, it is preferable to adjust the pigment composition so that the coating film formed by applying the present coating composition has a dark color tone. Specifically, it is preferable that the lightness L ^* defined in JIS Z 8729 of the coating film formed by applying the present coating composition is 5 to 80, preferably 10 to 60. It is more preferable.

  The content of the entire pigment with respect to the resin solid content is preferably 0.1 to 200% by mass, and more preferably 10 to 100% by mass. When the content of the entire pigment is small, the content of the composite pigment M is small and the heat reflection effect cannot be obtained sufficiently. On the other hand, if the content of the entire pigment is too large, the gloss may be lowered.

(Compound A)
Compound A is a compound represented by the general formula Si (OR) ₄ (wherein R may be the same or different and each represents an alkyl group having 1 to 2 carbon atoms ) or a partial condensate thereof.
By containing the compound A, the heat ray reflection performance of the composite pigment M can be stably maintained.

When the carbon number of R in the general formula exceeds 5, the effect of maintaining the heat ray reflection performance is lowered. Since particularly the effect of maintaining excellent heat reflecting performance can be obtained, R in the present invention, Ru alkyl group der of 1 or 2 carbon atoms. Particularly preferred compound A is tetramethoxysilane, tetraethoxysilane, or a partial condensate thereof.
Compound A preferably has a silica content of 20 to 60% by weight. If the silica content is too small, the effect of maintaining the heat ray reflection performance is lowered, and if it is too much, the storage stability is impaired.
The silica content is the ratio of compound A to silica (SiO ₂ ) obtained when 100% of the compound A is hydrolytically condensed.

The content of the compound A with respect to the resin solid content is preferably 0.5 to 60% by mass, and more preferably 2 to 30% by mass. If the content of Compound A is too small, the effect of maintaining the heat ray reflection performance is lowered, and if it is too much, foam, sagging, leveling, etc. may occur and paintability may be inferior.
This coating composition may contain an accelerator for promoting dealkoxy group reaction of Compound A and reticulation of molecules. Examples of the accelerator include conventionally known acidic catalysts such as hydrochloric acid and p-toluenesulfonic acid, and metal chelate compounds such as aluminum chelate.

It is considered that the effect of maintaining the heat ray reflection performance by the compound A is obtained even in the coating film using the composite pigment M because the dirt on the coating film causes a decrease in the heat ray reflection performance. .
In other words, since the heat ray reflection performance of the dark-colored coating film is not based on high brightness, the relationship between contamination and a decrease in heat ray reflection performance has not been considered in the past. However, as a result of the study, it was estimated that the heat ray reflection performance of the composite pigment M, which is a black pigment, is also inhibited by dirt.
Since compound A improves the stain resistance of the coating film by imparting hydrophilicity to the coating film, it is considered that the deterioration of the heat ray reflective performance of the composite pigment M can be prevented by improving the stain resistance. .

(resin)
Part or all of the resin of the present coating composition is preferably a fluororesin. By using a fluororesin, a coating film having good weather resistance can be obtained.
As the fluororesin, a fluoroolefin copolymer is preferable. The fluoroolefin copolymer is a copolymer of a fluoroolefin and another copolymerizable monomer copolymerizable with the fluoroolefin.

Examples of the fluoroolefin composing the fluoroolefin copolymer include C2-C3 fluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, and vinyl fluoride.
The proportion of the polymer units based on the fluoroolefin in the fluoroolefin copolymer is preferably 20 to 70 mol% in order to give sufficient weather resistance to the coating film.

  As another copolymerizable monomer constituting the fluoroolefin copolymer, a vinyl monomer, that is, a compound having a carbon-carbon double bond is preferable. Examples of the vinyl monomer include vinyl ether, allyl ether, carboxylic acid vinyl ester, carboxylic acid allyl ester, and olefin.

Examples of the vinyl ether include cycloalkyl vinyl ethers such as cyclohexyl vinyl ether, alkyl vinyl ethers such as nonyl vinyl ether, 2-ethylhexyl vinyl ether, hexyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, and t-butyl vinyl ether. Examples of allyl ethers include alkyl allyl ethers such as ethyl allyl ether and hexyl allyl ether.

Examples of the carboxylic acid vinyl ester or the carboxylic acid allyl ester include vinyl esters or allyl esters of carboxylic acids such as acetic acid, butyric acid, pivalic acid, benzoic acid, and propionic acid. Moreover, as a vinyl ester of a carboxylic acid having a branched alkyl group, commercially available Veova-9, Veova-10 (both manufactured by Shell Chemical Co., Ltd., trade names) and the like may be used. Examples of olefins include ethylene, propylene, and isobutylene.
Another copolymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

  Further, the fluoroolefin copolymer preferably has a functional group capable of reacting with a curing agent described later to form a crosslink. The type of the functional group can be appropriately selected depending on the combination with the curing agent. Representative examples include a hydroxyl group, a carboxyl group, a hydrolyzable silyl group, an epoxy group, and an amino group.

Examples of such a method for introducing a functional group include a method in which a monomer having a functional group is copolymerized in advance.
Examples of the monomer having a functional group include the following. 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, hydroxyalkyl vinyl ethers such as cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, vinyl esters of hydroxyl-containing carboxylic acids such as hydroxyalkyl vinyl crotonate, or Monomers having a hydroxyl group such as allyl ester. Monomers having a carboxyl group such as crotonic acid and undecenoic acid. Monomers having hydrolyzable silyl groups such as triethoxyvinylsilane. Monomers having an epoxy group such as glycidyl vinyl ether and glycidyl allyl ether. Monomers having an amino group such as aminopropyl vinyl ether and aminopropyl vinyl ether.

  Moreover, a functional group can also be introduce | transduced by the post reaction after superposition | polymerization. As this method, for example, a method of introducing a hydroxyl group by saponifying a polymer copolymerized with a carboxylic acid vinyl ester, a carboxyl group is introduced by reacting a polymer having a hydroxyl group with a polyvalent carboxylic acid or its anhydride. Examples include a method of reacting an isocyanate alkylalkoxysilane with a polymer having a hydroxyl group to introduce a hydrolyzable silyl group, a method of reacting a polymer having a hydroxyl group with a polyvalent isocyanate compound to introduce an isocyanate group, and the like. Is done.

  Preferable specific examples of the fluoroolefin copolymer include, for example, a copolymer of chlorotrifluoroethylene, cyclohexyl vinyl ether, alkyl vinyl ether and hydroxyalkyl vinyl ether, a copolymer of chlorotrifluoroethylene, alkyl vinyl ether and allyl alcohol, chloro Examples thereof include a copolymer of trifluoroethylene, an aliphatic carboxylic acid vinyl ester and a hydroxyalkyl vinyl ether, or a copolymer using tetrafluoroethylene in place of chlorotrifluoroethylene in these copolymers. These are commercially available under trade names such as Lumiflon (Asahi Glass) and Cefral Coat (Central Glass).

  A fluoroolefin type copolymer may be used individually by 1 type, and may be used in combination of 2 or more type. The number average molecular weight of the fluoroolefin copolymer is preferably 2,000 to 100,000, more preferably 6,000 to 30,000.

  As the resin of the present coating composition, in addition to the fluoroolefin copolymer, another fluororesin may be used alone or in combination with the fluoroolefin copolymer. In addition to fluororesin, alkyd resin, amino alkyd resin, polyester resin, epoxy resin, urethane resin, epoxy polyester resin, polyvinyl acetate resin, acrylic resin, vinyl chloride resin, phenol resin, silicone modified polyester resin, acrylic silicone A resin, a silicone resin, or the like may be used alone or in combination with a fluororesin.

(Curing agent)
The present coating composition can contain a curing agent. As the curing agent, various curing agents known as coating curing agents can be used. Specific examples of the curing agent include amino-based curing agents such as aminoplasts and urea resins, polyvalent isocyanate-based curing agents, and block polyvalent isocyanate-based curing agents.
A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type. Note that when a self-curing resin is used, a curing agent is not essential.
In addition, there is no limitation on the curing method of the present coating composition, and various curing methods such as a thermosetting type, a thermoplastic type, a room temperature drying type, and a room temperature curing type can be used.

(Other ingredients)
The coating composition may contain a fine particle filler, an additive, a solvent and the like as required.
As the fine particle filler, a hollow sphere that can impart heat insulation is generally used. As the hollow sphere, an inorganic balloon, a resin balloon or the like is known depending on the material. Specific examples include glass balloons, shirasu balloons, alumina balloons, zirconia balloons, and aluminosilicate balloons.
Additives are not particularly limited, for example, matting agents such as silica and alumina, antifoaming agents, leveling agents, anti-sagging agents, surface conditioners, viscosity modifiers, dispersants, ultraviolet absorbers, light stabilizers, Conventional additives such as a curing catalyst can be exemplified.

The present paint composition may be any of a non-aqueous solvent-type paint, a water-based paint, a non-water emulsion-type paint, and the like.
Therefore, the solvent is not particularly limited as long as it is generally used for paints. For example, petroleum, mixed solvents such as toluene, xylene, ExxonMobil Solvesso 100, ExxonMobil Solvesso 150 and the like, minerals Aromatic hydrocarbons such as spirit; esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; and water. These may be used alone or in combination of two or more.
When a solvent is used, it is preferable to use the resin solution by dissolving or dispersing the resin in the solvent.

(Production method)
The present coating composition is obtained by mixing the above-described components. The order of mixing is not particularly limited, but a method in which a pigment is mixed in advance with a resin solution and Compound A or Compound A and a curing agent are added thereto is preferable.
The accelerator for compound A is preferably added in advance to compound A. However, when it takes a long time to mix compound A into the resin solution and the pigment and to apply it, it is preferable to add the accelerator for promoting reticulation of compound A immediately before the coating composition is applied.
Additives such as matting agents, antifoaming agents, leveling agents, anti-sagging agents, surface conditioners, viscosity modifiers, dispersants, UV absorbers, light stabilizers, curing catalysts, etc., are mixed into the resin solution together with the pigment. It is preferable.

[Coated articles]
The coated article of the present invention is an article having a coating film formed by applying the coating composition to an article to be coated. Although the thickness of a coating film is not specifically limited, 5-100 micrometers is preferable and 20-50 micrometers is more preferable. When the film thickness is reduced, the concealability and weather resistance tend to be reduced, and when it is increased, construction problems such as sagging tend to occur.
There are various methods for coating the article to be coated with the coating composition. For example, brush coating, spray coating, dipping method, roll coater or flow coater can be applied.

There is no particular limitation on the material of the article to be coated. For example, there are inorganic materials such as concrete, natural stone, and glass, metals such as iron, stainless steel, aluminum, copper, brass, and titanium, or wood.
The coating composition is also suitable for coating on an organic substrate. In other words, it can be applied to other already formed coating films, adhesive layers, plastics, rubbers, and the like.
It is also suitable for coating on organic-inorganic composite materials such as fiber reinforced plastic, resin reinforced concrete, and fiber reinforced concrete.

  Articles to be coated include transportation equipment such as automobiles, trains and aircraft, civil engineering members such as bridge members and steel towers, industrial materials such as waterproof sheets, tanks and pipes, building exteriors, doors, window gate members, monuments, poles Building materials such as, road median strips, road members such as guardrails, communication equipment, electric and electronic parts.

When applying this coating composition to the article to be coated, pre-treatment that is usually used when applying paint such as surface polishing, sanding treatment, sealing treatment, primer treatment, primer coating, etc. Is preferred. The sealing agent, primer, and undercoat used here are not particularly limited and include organic solvent solutions, non-aqueous dispersions, aqueous solutions, and aqueous dispersions.
Examples of the primer or primer include epoxy resin-based, modified epoxy resin-based, vinyl resin-based, chlorinated rubber-based paints, and the like. If necessary, zinc phosphate, red lead, zinc dust, lead suboxide, Rust preventive pigments such as calcium lead acid, lead cyanamide, basic lead chromate, and basic lead sulfate, and scaly pigments such as iron oxide, mica, aluminum, and glass flakes may be included. Moreover, in order to improve rust prevention power, a zinc rich primer may be used, and two or more kinds of the above-mentioned solvent-based undercoat materials can be applied repeatedly.

The present invention is described in detail below, but the present invention is not limited thereto.
The base material, the main agent, and the curing agent composition used in Examples and Comparative Examples are as follows.
(Base material)
As the base material, an aluminum plate 140 mm × 240 mm × 0.5 mm treated with chromate was coated with an undercoat and an intermediate coat sequentially.
As the undercoat, Bon Epocoat 55MP-S, gray (Asahi Glass Coat and Resin, Epoxy paint) was used. As an intermediate coating agent, Bonflon # 1000 white (Asahi Glass Coat and Resin Co., Ltd., fluorine paint) was used.

(Main agent 1)
Fluororesin Lumiflon LF-200, a copolymer of chlorotrifluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether and hydroxyalkyl vinyl ether [manufactured by Asahi Glass Co., Ltd., hydroxyl group-containing fluoroolefin copolymer (hydroxyl value: 52 mgKOH / g) 60 mass% 15.0 g of xylene was added to 63.0 g. Next, 22.0 g of black 6301 (Mn, Bi composite oxide pigment, 29 mass% manganese content, manufactured by Asahi Kasei Kogyo Co., Ltd.) was added and dispersed with a sand mill. Further, a main ingredient 1 was prepared by adding 0.0005 g of dibutyltin dilaurate and stirring.

(Main agent 2)
16.0 g of xylene was added to 63.0 g of fluororesin Lumiflon LF-200. Next, 21.0 g of black 6303 (manufactured by Asahi Kasei Kogyo Co., Ltd., Mn, Y composite oxide pigment, manganese content 29% by mass) was added and dispersed by a sand mill. Furthermore, what added 0.0005g of dibutyltin dilaurate and stirred was used as the main ingredient 2.

(Main agent 3)
Xylene 34.0g was added to 63.0g of fluororesin Lumiflon LF-200. Next, 3.0 g of Mitsubishi Carbon Black MA-11 (Mitsubishi Chemical Corporation) was added and dispersed with a sand mill. Further, 0.0005 g of dibutyltin dilaurate was added and stirred, and the main agent 3 was used.

(Main agent 4)
10.0 g of fluororesin Lumiflon LF-200 and xylene 3.0 were added to 83.4 g of the main agent 3 (34.03 g as a solid content). Next, 3.6 g of titanium oxide (trade name CR-90, manufactured by Ishihara Sangyo Co., Ltd.) was added and dispersed with a sand mill. Further, the main agent 4 was prepared by adding 0.000083 g of dibutyltin dilaurate and stirring.

(Curing agent composition 1)
1.7 g of aluminum chelate D (produced by Kawaken Fine Chemical Co., Ltd., aluminum chelate compound) is added to 30.0 g of coronate HX (manufactured by Nippon Polyurethane, non-yellowing type isocyanate curing agent) and mixed, and MKC silicate is used as compound A. Curing agent composition 1 was prepared by adding 17.0 g of MS56S [Mitsubishi Chemical Co., Ltd., methyl silicate condensate having a silica content of 56 wt%] and mixing them.
(Curing agent composition 2)
Curing agent composition 2 was prepared by adding 18.7 g of xylene to 30.0 g of coronate HX.

Example 1
A coating composition obtained by mixing 12 g of the curing agent 1 with 100 g of the main agent 1 (59.8 g as a solid content) was applied on a substrate with a bar coater so as to have a film thickness of 30 μm. Thereafter, curing was performed for 7 days at a temperature of 23 ° C. and a relative humidity of 60%, and the test body of Example 1 was obtained.

(Example 2)
A coating composition obtained by mixing 12 g of the curing agent 1 with 100 g of the main agent 2 (59.8 g as a solid content) was applied on a substrate with a bar coater so as to have a film thickness of 30 μm. Thereafter, curing was performed for 7 days at a temperature of 23 ° C. and a relative humidity of 60% to obtain a test body of Example 2.

(Comparative Example 1)
A coating composition obtained by mixing 12 g of the curing agent 2 with 100 g of the main agent 3 (40.8 g as a solid content) was applied on a substrate with a bar coater so as to have a film thickness of 30 μm. Thereafter, curing was performed at a temperature of 23 ° C. and a relative humidity of 60% for 7 days to obtain a specimen of Comparative Example 1.

(Comparative Example 2)
A coating composition obtained by mixing 12 g of curing agent 1 with 100 g (43.3 g as a solid content) of main agent 4 was coated on a substrate with a bar coater so as to have a film thickness of 30 μm. . Thereafter, curing was performed for 7 days at a temperature of 23 ° C. and a relative humidity of 60% to obtain a test sample of Comparative Example 2.

(Comparative Example 3)
A coating composition obtained by mixing 12 g of the curing agent 2 with 100 g of the main agent 1 (59.8 g as a solid content) was applied on a substrate with a bar coater so as to have a film thickness of 30 μm. Thereafter, curing was performed for 7 days at a temperature of 23 ° C. and a relative humidity of 60%, to obtain a specimen of Comparative Example 3.

(Comparative Example 4)
A coating composition obtained by mixing 12 g of the curing agent 2 with 100 g of the main agent 2 (59.8 g as a solid content) was applied on a substrate with a bar coater so as to have a film thickness of 30 μm. Thereafter, curing was performed at a temperature of 23 ° C. and a relative humidity of 60% for 7 days to obtain a specimen of Comparative Example 4.

(Measurement of brightness)
About the surface of each test body, the lightness L ^* prescribed | regulated to JISZ8729 was measured using the spectrocolorimeter CM-2002 type | mold (Minolta company make). The results are shown in Table 1.
(Measurement of water contact angle)
A FACE contact angle meter CA-A type (manufactured by Kyowa Interface Chemical Co., Ltd.) was used to measure the contact angle of 0.005 ml of ion-exchanged water droplets. The results are shown in Table 1.

(Measurement of the initial temperature _{T 1)}
About each test body, the temperature of the coating film when an infrared lamp was irradiated for 10 minutes was measured in the following procedures.
First, the thermocouple was installed in the center part of the test body surface. In addition, an infrared lamp was installed 60 cm from the surface of the test body. The infrared lamp was turned on for 10 minutes and then turned off.
The surface temperature of the specimen was continuously measured with a thermocouple for 15 minutes from the start of lighting of the infrared lamp to 5 minutes after the light was turned off. The highest temperature obtained in the course of the 15 minutes was the initial temperature T _1. The results are shown in Table 1.

(Measurement of pollution after the temperature _{T 2)}
For each specimen, as shown in the procedure below, after carrying out accelerated soil adhesion in accordance with the antifouling test of the Civil Engineering Research Center method (antifouling material evaluation accelerated test method I), the post-contamination temperature T ₂ Was measured. The results are shown in Table 1.
(1) As a soiling substance, 95% by mass of deionized water was mixed well with 5% by mass of carbon black for pigment (manufactured by Deggsa, particle size 0.002-0.028 μm) to prepare a suspension.
(2) About 1/3 of the suspension volume was added to the suspension, and glass beads (2 mmφ) were added and stirred at 2500 rpm using a stirrer. Thereafter, the glass beads were removed to separate the carbon black suspension.
(3) About 200 g / m ² of the carbon black suspension was sprayed on the surface of the test body. After spraying, it was baked and dried with a dryer at 60 ° C. for 1 hour.
(4) After cooling to room temperature, the gauze was moved in the vertical, horizontal and vertical order on the surface of the test specimen under running tap water, and the soiled substances were washed off lightly.
(5) Then, it dried at room temperature and obtained the soil test body.
(6) Test body, except that instead of the dirty specimen, in the same manner as in the measurement of the initial temperature T _1, obtains the highest temperature obtained in the course of 15 minutes, was contaminated after the temperature T _2.

As shown in Table 1, in Examples 1 and 2 containing both the composite pigment M (containing Mn and an oxide of Bi or Y) and the compound A, both the initial temperature T ₁ and the post-contamination temperature T ₂ are low. The difference between the two was also small. That is, good heat ray reflection performance can be stably maintained.
On the other hand, in Comparative Example 1 containing neither the composite pigment M nor the compound A, the initial temperature T ₁ and the post-contamination temperature T ₂ were both high, and the difference between the _two was larger than in Examples 1 and 2.
Further, in Comparative Example 2 not containing the composite pigment M, both the initial temperature T ₁ and the post-contamination temperature T ₂ are high, and the initial temperature T ₁ and the post-contamination temperature T despite the compound A being contained. The difference between the _two was also very large.
In Comparative Examples 3 and 4 containing the composite pigment M (containing Mn and Bi or Y oxide) but not containing the compound A, the initial temperature T ₁ is low, but the post-contamination temperature T ₂ is high. Good heat ray reflection performance could not be maintained.

Claims (4)

A composite metal oxide pigment comprising an oxide of Bi and / or Y and an oxide of Mn;
A compound represented by the general formula Si (OR) ₄ (wherein R may be the same or different and each represents an alkyl group having 1 to 2 carbon atoms) or a partial condensate thereof;
Containing resin ,
A heat ray highly reflective coating composition, wherein a part or all of the resin is a fluororesin . The heat ray highly reflective coating composition according to claim 1, wherein the content of the composite metal oxide pigment is 0.1% by mass or more. Furthermore, the heat ray highly reflective coating composition of Claim 1 or 2 containing a hardening | curing agent. A coated article comprising a coating film formed by coating the heat ray highly reflective coating composition according to any one of claims 1 to 3 .