JP2006102670A - Method for forming heat-insulating coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the stain resistance, blister preventing properties, etc. of a coating film in a coating film forming method for applying an aqueous heat-insulating coating and an aqueous top coat in order. <P>SOLUTION: In the coating film forming method for applying the aqueous top coat after applying the aqueous heat-insulating coating, a coating which essentially comprises a synthetic resin emulsion (I), hollow particles (II), and an organic powder (III) comprising an organic powder (a) made of a polymer having an average particle diameter of 0.1-100 μm and a glass transition temperature of -60 to 60°C, and/or an organic powder (b) having a core part made of a polymer having an average particle diameter of 0.1-100 μm and a glass transition temperature of <30°C, and a shell part made of a polymer having a glass transition temperature of ≥30°C, and contains 0.5-200 pts.wt the component (II) and 3-400 pts.wt the component (III) with respect to 100 pts.wt. solid matter of the component (I) is used as the heat-insulating coating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming a heat insulating coating film.

  Conventionally, the exterior of a building has been painted to protect the building's enclosure or improve aesthetics. Among these, a painting method aimed at preventing an increase in the temperature of the building, reducing the amount of cooling used, suppressing the heat island phenomenon, and the like has attracted attention.

  As an example, in JP-A-1-126376 (Patent Document 1) and JP-A-1-263163 (Patent Document 2), a spherical hollow body such as a glass balloon, a shirasu balloon, or a resin balloon is formed on a structure substrate. A method of applying a top coat after applying a heat insulating paint is disclosed. However, all of the heat insulating paints described in these publications are paints using a solvent-based resin as a binder, and there is a possibility that the organic solvent may be released into the atmosphere at the time of painting. In particular, if a thick film is to be formed, the amount of organic solvent released increases in proportion to the film thickness. In general, organic solvents in paints are substances that are listed as one of the causative substances of photochemical smog and global warming. It is not preferable.

  On the other hand, a water-based heat-insulating paint using a synthetic resin emulsion as a binder has been proposed. If such a water-based heat insulating coating material is used, the amount of organic solvent released can be suppressed. For example, Japanese Patent Application Laid-Open No. 60-94470 (Patent Document 3) discloses an aqueous heat-insulating paint comprising a synthetic resin emulsion, hydraulic cement, and resin foam particles.

However, in the water-based heat-insulating paint described in the above publication, a synthetic resin emulsion having a relatively low glass transition temperature is employed in order to prevent the occurrence of cracks in the coating film. Therefore, when recoating the top coat on the water-based heat-insulating paint film, the glass transition temperature of the resin used in the top coat must be set low so that the top coat does not crack. It is difficult to prevent the adhesion of contaminants in the top coat.
Such adhesion of contaminants may cause an increase in the temperature of the top coating film and induce the occurrence of swelling of the coating film. In particular, when the thermal insulation performance is improved by increasing the film thickness of the lower thermal insulation coating, the heat generated in the upper coating becomes difficult to conduct and diffuse in the direction of the lower coating. Problems such as occurrence of blistering are more likely to occur.

JP-A-1-126376 JP-A-1-263163 JP 60-94470 A

  The present invention has been made in view of the above-described problems, and in a coating film forming method in which a water-based heat-insulating coating material and a water-based top coating material are applied in order, the stain resistance, swelling prevention, and the like are improved. It is intended.

  As a result of diligent studies to achieve the above-mentioned object, the present inventor has conceived a method of applying an aqueous top coating after applying a water-based heat-insulating coating containing a specific organic powder as a constituent component, The present invention has been completed.

  That is, the present invention has the following features.

1. In the method of forming a heat-insulating coating film in which a water-based top coat is applied after applying a water-based heat-insulating paint, as the water-based heat-insulating paint,
Synthetic resin emulsion (I), hollow particles (II), and organic powder (a) composed of a polymer having an average particle diameter of 0.1 to 100 μm and a glass transition temperature of −60 to 60 ° C., and / or average Organic powder comprising an organic powder (b) having a particle diameter of 0.1 to 100 μm and having a core part made of a polymer having a glass transition temperature of less than 30 ° C. and a shell part made of a polymer having a glass transition temperature of 30 ° C. or more. Body (III)
Is used as an essential component, and it contains 0.5 to 200 parts by weight of component (II) and 3 to 400 parts by weight of component (III) with respect to 100 parts by weight of the solid content of component (I). A method for forming a heat-insulating coating film.
2. The water-based top coat is a pigment,
Organic powder (a) made of a polymer having an average particle size of 0.1 to 100 μm and a glass transition temperature of −60 to 60 ° C. and / or an average particle size of 0.1 to 100 μm and a glass transition temperature 1. An organic powder comprising an organic powder (b) having a core part made of a polymer of less than 30 ° C. and a shell part made of a polymer having a glass transition temperature of 30 ° C. or higher. The formation method of the heat insulation coating film of description.

  In the coating film forming method of the present invention, since both water-based paints are used as the heat-insulating paint and the top-coat paint, it is possible to perform coating in consideration of the environment. Moreover, in the present invention, it is possible to improve the stain resistance, the swelling prevention property and the like in the formed coating film.

  Hereinafter, the best mode for carrying out the present invention will be described.

The water-based heat insulating paint in the present invention is
Synthetic resin emulsion (I) (hereinafter referred to as component (I)),
Hollow powder (II) (hereinafter referred to as component (II)) and organic powder (a) composed of a polymer having an average particle size of 0.1 to 100 μm and a glass transition temperature of −60 to 60 ° C., and / or An organic substance comprising an organic powder (b) having an average particle diameter of 0.1 to 100 μm and having a core part made of a polymer having a glass transition temperature of less than 30 ° C. and a shell part made of a polymer having a glass transition temperature of 30 ° C. or more. Powder (III) (hereinafter referred to as (III) component)
Is contained as an essential component.

  The component (I) in the water-based heat insulating coating is a component that acts as a binder. Specifically, as the component (I), for example, a vinyl acetate resin emulsion, a vinyl chloride resin emulsion, an epoxy resin emulsion, an acrylic resin emulsion, a urethane resin emulsion, an acrylic silicon resin emulsion, a fluororesin emulsion, or a composite system thereof. Can be mentioned. These can be used alone or in combination of two or more.

Such component (I) may have crosslinking reactivity. When the component (I) is a crosslinking reaction type synthetic resin emulsion, the water resistance, weather resistance, adhesion and the like of the coating film can be improved. The crosslinking reaction type synthetic resin emulsion may be either one that causes a crosslinking reaction by itself or one that causes a crosslinking reaction by a separately mixed crosslinking agent. Such crosslinking reactivity includes, for example, carboxyl group and metal ion, carboxyl group and carbodiimide group, carboxyl group and epoxy group, carboxyl group and aziridine group, carboxyl group and oxazoline group, hydroxyl group and isocyanate group, carbonyl group and hydrazide group. It can be imparted by combining reactive functional groups such as epoxy groups and amino groups, aldo groups and semicarbazide groups, keto groups and semicarbazide groups, and alkoxyl groups.
Moreover, a core-shell type synthetic resin emulsion can also be used as the component (I).

  Although the manufacturing method of (I) component is not specifically limited, For example, emulsion polymerization, soap-free emulsion polymerization, dispersion polymerization, feed emulsion polymerization, feed dispersion polymerization, seed emulsion polymerization, seed dispersion polymerization, etc. are employable.

The glass transition temperature (hereinafter referred to as “Tg”) of the component (I) may be appropriately set within the range of −50 to 50 ° C. In the present invention, the component (I) Can be set relatively high (preferably -5 to 50 ° C, more preferably 5 to 50 ° C, and further preferably 15 to 50 ° C). When Tg is higher than this range, the followability to the ground becomes insufficient, and cracks are likely to occur in the coating film. If the Tg is too low, a resin having a low Tg must be used even in the top coat, and contaminants tend to adhere to the coating surface. Moreover, it becomes easy to generate | occur | produce a swelling in a coating film.
The Tg in the present invention is a value obtained from the formula of Fox from the type of monomer constituting the component (I) and its constituent ratio.
(I) The average particle diameter of a component is about 0.05-0.4 micrometer normally.

The hollow particles (II) in the water-based heat insulating paint are components that impart heat insulating properties to the coating film. Examples of the component (II) include hollow ceramic beads and hollow resin beads. Examples of the ceramic component constituting the hollow ceramic beads include sodium silicate glass, aluminum silicate glass, borosilicate soda glass, carbon, alumina, silica, zirconia, shirasu, obsidian and the like. Examples of the resin component constituting the hollow resin beads include acrylic resin, styrene resin, acrylic-styrene copolymer resin, acrylic-acrylonitrile copolymer resin, acrylic-styrene-acrylonitrile copolymer resin, acrylonitrile-methacrylonitrile copolymer resin, Acrylic-acrylonitrile-methacrylonitrile copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, polyethylene resin, polypropylene resin, polyurethane resin and the like can be mentioned. These can be used alone or in combination of two or more. The component (II) that is a resin component is advantageous in that it has a low thermal conductivity.
Examples of the shape of the component (II) include a spherical shape, an elliptical spherical shape, and a flat spherical shape.

  The component (II) has a hollow structure, and focusing on the structure, it is classified into an open cell type hollow particle and a closed cell type hollow particle. Of these, closed-cell hollow particles are preferred in the present invention. When closed cell-type hollow particles are used, it is possible to prevent intrusion of a resin component or the like into the cell, so that high heat insulation performance can be exhibited. The internal structure of the closed-cell type hollow particles may be a single hollow type having one hollow per particle, or a multi-hollow type having two or more hollows per particle. .

  The hollow part of the component (II) is usually filled with gas, but it is also possible to use a hollow part that is vacuum. Examples of the gas that can be filled in the hollow portion include air, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, fluorinated chlorinated hydrocarbons, and volatile monomers. Of these, aliphatic hydrocarbons are preferred.

(II) The average particle diameter of a component is 0.1-200 micrometers normally, Preferably it is 1-150 micrometers. When the average particle diameter is in such a range, a coating film having high smoothness can be formed. In addition, concealability, infrared reflectivity and the like can be improved.
The density of the component (II) is usually 0.01 to 1 g / cm 3, preferably 0.01 to 0.5 g / cm 3. When the density is in such a range, heat insulation, light weight, etc. can be enhanced.

  In the water-based heat-insulating paint, by mixing a specific organic powder as the component (III), the followability to the base is increased, and the occurrence of cracks in the coating film can be suppressed. In addition, since the component (III) has a lower thermal conductivity than the inorganic powder, it is advantageous in terms of heat insulation.

  The first (III) component is an organic powder (hereinafter referred to as “component (a)”) having an average particle size of 0.1 to 100 μm and comprising a polymer having a Tg of 60 to 60 ° C. (A) The average particle diameter of a component is 0.1-100 micrometers normally, Preferably it is 0.5-50 micrometers, More preferably, it is 1-30 micrometers.

  The polymer of component (a) is formed by copolymerizing various polymerizable monomers. Examples of polymerizable monomers that can be used include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, and lauroyl. Examples include alkyl (meth) acrylate styrene such as (meth) acrylate and stearyl (meth) acrylate, aromatic vinyl monomers such as vinyltoluene and α-methylstyrene. A polyfunctional monomer having two or more vinyl groups in the molecule can also be used.

  (A) Tg of a component is -60-60 degreeC normally, Preferably it is -50-50 degreeC, More preferably, it is -40-40 degreeC. (A) Tg of a component can be adjusted by setting suitably the kind and ratio of the monomer which comprise a polymer. When Tg is too high, sufficient performance cannot be obtained in the followability to the base, and when Tg is too low, it is disadvantageous in terms of contamination resistance.

In the water-based heat-insulating coating material, the second (III) component has an average particle diameter of 0.1 to 100 μm, and has a core part made of a polymer having a Tg of less than 30 ° C. and a shell part made of a polymer having a Tg of 30 ° C. or more. Organic powder (hereinafter referred to as “component (b)”) can be used. By using such a component (b), it is possible to further improve the followability to the base and the crack prevention property. In this case, the component (a) and the component (b) can be mixed and used.
(B) The average particle diameter of a component is 0.1-100 micrometers normally, Preferably it is 0.5-50 micrometers, More preferably, it is 1-30 micrometers.

(B) Tg of the core part of a component is usually less than 30 degreeC, Preferably it is -60-20 degreeC, More preferably, it is -60-10 degreeC. The Tg of the shell part is usually 30 ° C. or higher, preferably 50 to 140 ° C., more preferably 60 to 130 ° C.
In the component (b), as long as the Tg of the core part and the shell part is within a predetermined range, the monomer constituting the polymer is not particularly limited, and the same monomer as the component (a) is used. it can.
The component (a) and the component (b) are both non-film-forming powders and are different materials from the component (I) having film-forming properties.

  The water-based heat-insulating coating material preferably contains infrared reflective powder (IV) (hereinafter referred to as “(IV) component”). This component (IV) is suitable in that it has a function of suppressing heat storage of the coating film by sunlight. Examples of the component (IV) include aluminum flake, titanium oxide, barium sulfate, zinc oxide, calcium carbonate, silicon oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, antimony oxide, tin oxide, calcium oxide, and lead white. , Zinc sulfide, alumina and the like. These can be used alone or in combination of two or more. Among these, in this invention, 1 or more types chosen from a titanium oxide and a zinc oxide are suitable.

  The average particle size of the component (IV) is usually 0.1 to 10 μm, preferably 0.1 to 1 μm. When the average particle diameter is in such a range, infrared reflectivity can be enhanced.

The weight ratio of each component in the water-based heat-insulating coating is 0.5 to 200 parts by weight (preferably 1 to 100 parts by weight) of (II) component, and (III) with respect to 100 parts by weight of the solid content of component (I). The component is 3 to 400 parts by weight (preferably 5 to 300 parts by weight). When the component (VI) is used, the component (IV) is 1 to 400 parts by weight (preferably 2 to 200 parts by weight) with respect to 100 parts by weight of the solid content of the component (I). By mixing each component in such a ratio in the water-based heat-insulating paint, the heat-insulating property, infrared reflectivity, etc. are excellent, and adhesion with the top-coat paint is high, and a coating film having sufficient coating strength is formed. It becomes possible.
When the amount of the component (II) is less than 0.5 parts by weight, sufficient heat insulating performance cannot be obtained. When the amount is more than 200 parts by weight, swelling, peeling, cracking and the like are likely to occur.
When the amount of the component (III) is less than 3 parts by weight, the Tg of the component (I) must be set low in order to ensure the crack prevention property of the coating film, which is disadvantageous in terms of contamination resistance. . When the amount is more than 400 parts by weight, the adhesion may be lowered.
When the component (IV) is less than 1 part by weight, the coating film is likely to store heat by sunlight. In addition, sufficient coating strength cannot be obtained, and swelling, peeling and the like are likely to occur. When the amount is more than 400 parts by weight, peeling, cracking and the like are likely to occur.

In the water-based heat-insulating paint of the present invention, in addition to the above-mentioned components, additives that can be blended in a normal paint can also be added within a range that does not impair the effects of the present invention. Examples of such additives include crosslinking agents, catalysts, pigments, dyes, aggregates, matting agents, fibers, thickeners, leveling agents, plasticizers, film-forming aids, antifreeze agents, preservatives, Antibacterial agents, antifungal agents, dispersants, antifoaming agents, pH adjusting agents, ultraviolet absorbers, antioxidants and the like can be mentioned.
The aqueous heat-insulating paint of the present invention can be obtained by uniformly mixing the above components by a conventional method.

The water-based heat insulating paint of the present invention is mainly applied to the surface of a building exterior surface such as a roof, a rooftop, or an outer wall. Among these, it can be suitably applied particularly to the outer wall surface.
The base material of the exterior surface is not particularly limited, and examples thereof include concrete, mortar, metal, plastic, or various boards such as a slate plate, an extruded plate, a siding board, and an ALC plate. These base materials may have already been formed with a coating film. The water-based heat-insulating coating is applied mainly to existing buildings, but various boards can be pre-coated at a factory or the like in advance. The building to be painted may be a newly built property or a renovated property.

  The water-based heat-insulating paint of the present invention can be directly applied to the substrate to be coated. Before applying the water-based heat insulating paint, it may be treated with, for example, a sealer or a filler, if necessary.

In the application of the water-based heat-insulating paint, a known coating instrument can be used. For example, a spray, a roller, a brush, a trowel, or the like can be used as the coating instrument. When pre-coating is performed, a roll coater, a flow coater or the like can also be used. When painting, the paint can be diluted with water. What is necessary is just to set the mixing amount of water suitably according to the coating instrument to be used, a desired surface shape, etc. Examples of the surface shape that can be formed in the water-based heat insulating paint include a smooth shape, a yuzu skin shape, a spray tile shape, and a ripple shape.
The dry film thickness of the coating film formed with the aqueous heat-insulating paint is usually 0.1 to 10 mm, preferably 0.5 to 5 mm.

  In this invention, after apply | coating the above-mentioned water-based heat insulation coating material with respect to the surface of a building exterior surface, a water-based top coating material is applied. As the aqueous top coat in the present invention, a paint capable of forming a relatively hard coating film can be used. Therefore, the stain resistance of the coating film can be improved as compared with the conventional case.

A synthetic resin emulsion is usually used as the binder in the aqueous top coating. Examples of such synthetic resin emulsions include acrylic resins, urethane resins, acrylic urethane resins, silicone resins, acrylic silicone resins, vinyl acetate resins, vinyl acrylate resins, fluororesins, and the like, one or two of these. More than seeds can be used. These may be those having a crosslinked structure in the resin, or those having a crosslinked structure after the formation of the coating film. Such a crosslinked structure can improve adhesion, weather resistance, water resistance, chemical resistance, moisture permeability, and the like. Such a synthetic resin emulsion may be of a core-shell type.
The Tg of the synthetic resin emulsion in the aqueous top coating is usually -5 to 80 ° C, preferably 10 to 60 ° C, more preferably 20 to 50 ° C.

As the water-based top coating material, those containing the component (III) in the above water-based heat insulating coating material are suitable. By using such a specific organic powder for an aqueous top coating, it is possible to further improve the stain resistance and crack resistance of the coating film.
The content of the component (III) in the aqueous top coat may be 1 to 400 parts by weight (preferably 2 to 200 parts by weight) with respect to 100 parts by weight of the solid content of the synthetic resin emulsion.

  The water-based top coating material may be either a colored type or a clear type. When the water-based top coat is a clear type, it is desirable that the above-mentioned water-based heat insulating paint contains the component (IV) as an essential component.

  In the coloring type water-based top coating, it is desirable that the water-based top coating itself contains an infrared reflecting powder and / or an infrared transmitting powder. When the aqueous top coating contains such a powder component, it is possible to color the top coating in a desired color while suppressing heat accumulation of the top coating by sunlight.

  Of these, the infrared reflective powder can be the same as the component (IV) of the water-based heat insulating paint, such as aluminum flakes, titanium oxide, barium sulfate, zinc oxide, calcium carbonate, silicon oxide, Examples thereof include magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, antimony oxide, tin oxide, calcium oxide, white lead, zinc sulfide, and alumina. These can be used alone or in combination of two or more.

  Examples of the infrared transmitting powder include perylene pigment, azo pigment, yellow lead, petal, vermilion, titanium red, cadmium red, quinacridone red, isoindolinone, benzimidazolone, phthalocyanine green, phthalocyanine blue, cobalt blue, Induslen blue, ultramarine blue, bitumen and the like can be mentioned, and one or more of these can be used. There is a limit to the hue that can be expressed only by using the above-mentioned infrared reflective powder, but it is possible to form a coating film of various hues by appropriately combining these infrared transparent powders. .

  The content of the infrared reflecting powder and / or the infrared transmitting powder is desirably 1 to 40 parts by weight with respect to 100 parts by weight of the solid content of the synthetic resin emulsion.

  In the water-based top coating material, in addition to the above-described components, additives that can be usually added to the coating material can be added within a range that does not impair the effects of the present invention. Examples of such additives include cross-linking agents, catalysts, matting agents, fibers, thickeners, leveling agents, plasticizers, film-forming aids, antifreezing agents, antiseptics, antibacterial agents, antifungal agents, Dispersing agents, antifoaming agents, pH adjusting agents, ultraviolet absorbers, antioxidants and the like can be mentioned. The aqueous top coating composition of the present invention can be obtained by uniformly mixing the above components by a conventional method.

The water-based top coating can be applied after the surface of the water-based heat-insulating coating is dried.
In the application of the water-based top coating material, a known coating device can be used. For example, a spray, a roller, a brush, or the like can be used as the coating instrument. When pre-coating is performed, a roll coater, a flow coater or the like can also be used. When painting, the paint can be diluted with water. What is necessary is just to set the mixing amount of water suitably according to the coating instrument etc. to be used.
The dry film thickness of the coating film formed with the aqueous top coating is usually 5 to 200 μm.

  Examples and Comparative Examples are shown below to clarify the features of the present invention.

(Insulating paint 1-5)
The following raw materials were mixed at the ratios shown in Table 1 (numbers in the table are parts by weight) and stirred uniformly to produce heat-insulating paints 1-5. Moreover, the top coating materials 1-3 were manufactured by mixing each raw material by the ratio shown in Table 2 (the number in a table | surface is a weight part), and stirring uniformly.

Resin 1: Acrylic resin emulsion (solid content 50% by weight, Tg 20 ° C.)
Resin 2: Acrylic resin emulsion (solid content 50% by weight, Tg-20 ° C.)
Resin 3: Acrylic silicone resin emulsion (solid content 50% by weight, Tg 23 ° C.)
Resin 4: Acrylic silicone resin emulsion (solid content 50% by weight, Tg 28 ° C.)
Resin 5: Acrylic silicone resin emulsion (solid content 50% by weight, Tg 6 ° C.)
Hollow particles: closed cell hollow resin beads (acrylic-acrylonitrile copolymer resin, average particle diameter 45 μm, density 0.025 g / cm 3)
Organic powder 1: acrylic polymer powder (average particle size 8 μm, Tg 20 ° C., specific gravity 1.0)
Organic powder 2: Core-shell type acrylic polymer powder (average particle size 8 μm, core portion Tg-54 ° C., shell portion Tg 105 ° C., specific gravity 1.0)
Organic powder 3: Acrylic polymer powder (average particle diameter 8 μm, Tg 105 ° C., specific gravity 1.0)
・ Infrared reflective powder: Titanium oxide (average particle size 0.3μm)
-Film-forming aid: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate-Thickener: Polycarboxylic acid thickener-Antifoaming agent: Silicone defoamer

Example 1
Spray coating of heat-insulating paint 1 on a slate plate of 300 x 225 mm, drying for 8 hours under an atmosphere of temperature 20 ° C. and relative humidity 65% RH (hereinafter referred to as “standard state”), spray-coating top coat 1 A test plate was prepared by curing for 14 days in a standard state. At this time, the heat insulating paint was applied so that the dry film thickness was 1 mm, and the top coat was applied so that the dry film thickness was 50 μm.
The obtained test plate was subjected to a total of 10 cycles of hot / cold repeated tests with water immersion (20 ° C.) for 18 hours → −20 ° C. for 3 hours → 50 ° C. for 3 hours to change the surface state of the coating film (swelling) The presence or absence of peeling, cracking, etc.) was visually observed. Evaluation is “◎” when no abnormality is observed, “○” when almost no abnormality is observed, “△” when abnormality is observed, and “×” when abnormality is significantly observed. It was.
In addition, the test plate obtained by the above method was installed in the south face in Ibaraki City, Osaka Prefecture, and was exposed outdoors, and the degree of dirt after one month was 4 levels (good ◎>○>△> × poor) ).

On the other hand, a 450 × 450 × 450 mm box was prepared using a 12 mm thick slate plate in order to conduct a heat insulation test. The heat insulating paint 1 was spray-coated on the surface, dried for 8 hours in a standard state, and then the top coat paint 1 was spray-coated, and further cured for 14 days to obtain a specimen for the heat insulating test. At this time, the heat insulating paint was applied so that the dry film thickness was 1 mm, and the top coat was applied so that the dry film thickness was 50 μm.
Next, the obtained specimen was irradiated with an infrared lamp (250 W) from a distance of 60 cm for 90 minutes, and the temperature change inside the box during that time was measured. The evaluation was “◯” when the temperature change was less than 5 ° C., “△” when the temperature change was 5 ° C. or more and less than 10 ° C., and “X” when the temperature change was 10 ° C. or more. It was.

(Examples 2-3, Comparative Examples 1-3)
The test was performed in the same manner as in Example 1 except that the heat insulating paint and the top coat paint shown in Table 3 were used. The test results are shown in Table 3.

Claims (2)

In the method of forming a heat-insulating coating film in which a water-based top coat is applied after applying a water-based heat-insulating paint, as the water-based heat-insulating paint,
Synthetic resin emulsion (I), hollow particles (II), and organic powder (a) composed of a polymer having an average particle diameter of 0.1 to 100 μm and a glass transition temperature of −60 to 60 ° C., and / or average Organic powder comprising an organic powder (b) having a particle diameter of 0.1 to 100 μm and having a core portion made of a polymer having a glass transition temperature of less than 30 ° C. and a shell portion made of a polymer having a glass transition temperature of 30 ° C. or higher. Body (III)
Is used as an essential component, and it contains 0.5 to 200 parts by weight of component (II) and 3 to 400 parts by weight of component (III) with respect to 100 parts by weight of the solid content of component (I). A method for forming a heat-insulating coating film. The water-based top coat is a pigment,
Organic powder (a) made of a polymer having an average particle diameter of 0.1 to 100 μm and a glass transition temperature of −60 to 60 ° C. and / or an average particle diameter of 0.1 to 100 μm and a glass transition temperature 2. The organic powder comprising an organic powder (b) having a core part made of a polymer having a temperature of less than 30 ° C. and a shell part made of a polymer having a glass transition temperature of 30 ° C. or higher. A method for forming a heat-insulating coating film.