JP2001032399A - Thermal insulating construction material equipped with heat reflection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide thermal insulating construction materials excellent in weight reduction and insulating suitable for roofing, enabling an optional color to color in them and abounding in versatility with high productivity at a low cost. SOLUTION: A reflective coated film 2 with at least one layer containing 2-70 wt.% of pigment having more than 30% of solar heat reflection factor (RE/NIR) in the wavelength area of 800-2100 nm is applied to one side of a metal substrate having more than 20% of solar heat reflection factor (RE) in the wavelength area of 350-2100 nm such as plated steel plate, aluminum plate, stainless steel plate or the like. A thermal insulating material 7 (for example, thin resin foam) is stuck on the rear side of the substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating building material having a heat ray reflecting function, which is preferably used mainly as a building exterior material such as a roofing material and hardly raises the indoor temperature even when exposed to sunlight.

[0002]

2. Description of the Related Art House structures are being strengthened from the viewpoint of improving disaster prevention and the like. Roofing materials include new ceramics, metal roofs, etc., in addition to Japanese tiles.

[0003] Metal roofs weigh about 1/1 compared to Japanese tiles.
0, it is about 1/3 lighter than new ceramics, so it is considered to be a preferable material for promoting structural reinforcement and weight reduction. However, since metal has a higher thermal conductivity than ceramic materials, metal roofing material has the disadvantage that solar heat is easily conducted to the attic, radiated into the room from the back side, and the indoor temperature tends to increase. .

As a method of suppressing the influence of solar heat, there is a method of bonding a heat insulating material to the back surface of a metal roofing material. But,
Usually, since a method of bonding a heat insulating material after forming a metal plate is adopted, the manufacturing process of the bonding material is complicated, and the initial cost required for dedicated equipment is high, so it lacks economy. There's a problem.

[0005] There is also a method of applying a heat-shielding heat-insulating paint to a metal roofing material. The heat-insulating heat-insulating paint is a special paint that uses ceramic having a large number of hollow bubbles as a pigment.
To achieve the effect, it is necessary to increase the coating film thickness,
There are problems such as loss of economy and design. Therefore, it has not been widely adopted for general use.

Japanese Unexamined Patent Publication No. 5-293434 discloses an automobile body or automobile coated with a low-brightness solar-shielding top coat obtained by combining a plurality of pigments having a constant solar heat reflectance and additively mixing colors. Parts are disclosed.
This technique enhances solar heat reflectivity by a top coat having excellent heat reflectivity. However, the solar heat shielding property cannot always be sufficiently ensured only by the coating film.

According to the above publication, in such a case, it is better to use an aluminum base having good heat shielding properties. However, aluminum has low strength, is difficult to weld, and has a very high material cost. However, there is a problem in adopting it widely for general use. Furthermore, even if an aluminum base is adopted, the reflectance of the base may be low depending on the type and amount of the added element, the surface roughness and the oxide film thickness, and the solar heat reflectivity may be poor when the above coating is applied. .

[0008]

DISCLOSURE OF THE INVENTION The present invention is excellent in economic efficiency and versatility, suitable for building exterior materials such as roofs.
An object of the present invention is to provide a metal building material whose outer surface can be painted in a desired color and has little heat dissipation to the back side, and has excellent solar heat reflection and heat insulation.

[0009]

Means for Solving the Problems In a building, its landscape and design are evaluated as important factors. For this reason, it is necessary for a painted metal plate used as a building exterior material to be able to be freely colored into any color or pattern.

[0010] Most of the solar heat has a wavelength of 0.3 to 2.1.
It is irradiated as visible light or near infrared light of μm (300 to 2100 nm). Therefore, it is desirable that a coated metal plate used as a building exterior material has a high reflectance of visible light and near-infrared light in the above wavelength range so as not to absorb solar heat as much as possible.

[0011] From the above viewpoints, the present inventors have examined in detail the influence of a substrate and a coating film on the solar heat reflectivity of a coated metal plate obtained by coating a metal substrate. As a result, the following knowledge was obtained regarding effective prevention of temperature rise due to solar heat.

A. The color perceived visually is determined by the reflectance of light from the object surface at wavelengths in the visible light range (380 to 780 nm). That is, the solar heat reflectance in the visible light region of the painted metal plate is determined by the color of the coating film. Therefore, unless the color of the coating film is changed, the amount of solar heat absorption in the visible light wavelength region is the same, and it is difficult to change the reflectance depending on the wavelength in the visible light region while maintaining the color.

However, it has been found that the solar heat reflectivity can be improved by increasing the spectral reflectance in the near infrared region (0.8 to 2.1 μm) outside the visible light region of the coating film. Since the reflectance in the visible light region is not limited, the color of the coating film can be freely colored to a desired color. In order to increase the spectral reflectance in the near infrared region of the coating film, it is effective to add a pigment having a solar heat reflectance of 30% or more in the near infrared region to the coating film in a certain amount or more. Hereinafter, such a pigment having good solar heat reflectivity is also simply referred to as “reflective pigment”, and a coating film having a high solar heat reflectance containing a certain amount or more of this reflective pigment is also referred to as “reflective coating film”.

In the coating of a metal plate, an undercoating film is provided between the outer layer coating film and the substrate for the purpose of improving the adhesion of the outer layer coating film and improving the rust-prevention property and finish of the coating as a coated metal plate. (Primer) or an intermediate coating film (hereinafter, these are collectively referred to as “inner coating film”) in some cases.

When the metal plate has a plurality of coating films as described above, two or more coating films may be used as reflective coating films.
The most effective way to improve solar heat reflectivity is to include a reflective pigment in the outer layer coating film. However, for example, in the case where the outer layer coating film is thin and the concealing property is not sufficient even if the reflective pigment is contained, in addition to the outer layer coating film, at least one inner layer coating film may have the above-mentioned reflective pigment. In a suitable amount, a coated metal plate having sufficient solar heat reflectivity can be obtained.

B. As described above, even with a coated metal plate provided with a coating excellent in solar heat reflectivity at a wavelength in the near-infrared region, the solar heat reflection performance is lower than that of the coating while maintaining color. It can be affected by the layer (that is, the surface of the metal substrate). In particular, when the solar heat reflective coating is thin, the hiding power is insufficient, and the reflectance of the substrate is likely to be affected.

Therefore, the coated metal plate having solar heat reflection, which maintains both color maintenance and solar heat reflectivity, prevents the substrate from absorbing light having a wavelength of 350 to 2100 nm in the visible light region and the near infrared region. It is effective to In other words, as if the sunlight reaching the substrate is reflected and escaped,
It is advantageous that the reflectance in the wavelength region on the substrate surface is high.

C. Even if the solar heat reflectivity of the coating film and the substrate of the coated metal plate is improved, there is a limit in preventing the absorption of solar heat by itself. Become. By attaching a heat insulating material to the surface of the substrate opposite to the painted surface (hereinafter also referred to as the back surface), it is possible to significantly suppress the rise in room temperature, and to achieve a heat insulating effect that could not be achieved with conventional metal building materials Can be shown. This is because the amount of solar heat absorbed by the substrate is reduced by the above-described reflective coating, so that the heat insulating material can sufficiently absorb the amount of heat transmitted from the substrate, and the amount of heat dissipated indoors is extremely reduced. It is thought that it is.

The present invention, which has been completed on the basis of the above findings, is a heat-insulating building material in which one surface of a metal substrate is a painted surface and a heat-insulating material is disposed on the opposite surface, and the surface of the metal substrate is a painted surface. Solar thermal reflectance (R _E ) in the wavelength range of ~ 2100 nm
Pigment having a solar thermal reflectance (R _{E / NIR} ) of 30% or more in the wavelength region of 800 to 2100 nm.
A heat-insulating building material having a heat ray reflecting function, comprising at least one coating film containing about 70% by weight.

In the present invention, the solar thermal reflectance used for the metal substrate and the pigment is the spectral reflectance (Rλ).
This is the solar thermal reflectance calculated in consideration of the intensity of the spectrum in the wavelength region calculated. 350-2100 solar reflectance R _E in the wavelength region of nm is obtained by the following formula (1), 8
The solar thermal reflectance R _{E / NIR in} the wavelength range of 00 to 2100 nm is obtained by the following equation (2). The spectral reflectance (Rλ) for determining the solar thermal reflectance can be measured using a spectrophotometer.

[0021]

(Equation 1)

Where R _E : solar thermal reflectance (%) in the wavelength range of 350 to 2100 nm
, Eλ: spectral intensity of solar heat, Rλ: spectral reflectance (measured with a spectrophotometer).

[0023]

(Equation 2)

Here, RE _{/ NIR} : solar thermal reflectance (%) in a wavelength region (near infrared region) of 800 to 2100 nm, Eλ: spectral intensity of solar heat, Rλ: spectral reflectance (measured by a spectrophotometer) .

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the heat insulating building material of the present invention will be described more specifically. In the following description,
% Means% by weight unless otherwise specified.

The heat-insulating building material of the present invention is such that one surface of a metal substrate is a painted surface and a heat-insulating material is disposed on the opposite surface of the substrate. The painted surface includes at least one reflective coating containing a reflective pigment. The substrate is used with the surface of the heat insulating material facing the inside of the room and the painted surface provided with the reflective coating facing outward. Hereinafter, the surface of the substrate on which the heat insulating material is disposed is referred to as the back surface, and the surface of the substrate provided with the reflective coating is referred to as the front surface.

Since the heat-insulating building material of the present invention is provided with a reflective coating on the surface on the outer surface side, it can reflect a considerable portion of solar radiation and reduce the amount of solar heat absorbed. Since the reduced absorbed solar heat can be sufficiently absorbed by the heat insulating material disposed on the back side, the amount of heat dissipated to the indoor side is significantly reduced as compared with the conventional metal building material, and the metal building material has excellent heat insulating properties.

Substrate : The metal substrate used in the heat-insulating building material of the present invention has a wavelength range of 350 to 2100 nm (that is, a wavelength range of 350 to 2100 nm calculated from the spectral reflectance of the surface thereof (ie, the painted surface on which the heat insulating material is not disposed). The solar thermal reflectance (R _E ) in the visible light and near infrared regions is 20% or more. Backside of R _E of the substrate is not limited. The substrate often has the same R _E on both surfaces, but only the front surface has an R _{E of} 20% or more and the R
_E can also use metal substrates lower than 20%.

The reason that the target wavelength is limited as described above is that most of the solar heat is included in the above-mentioned wavelength region. Therefore, if the reflectance in this wavelength region is specified, it is not enough to evaluate the solar thermal reflectivity. This is because it has accuracy. And R _E is less than 20% of the substrate surface, even to form a reflective coating containing reflective pigment thereon, solar reflectivity of the entire coated metal plate becomes insufficient, absorption of solar heat As a result, the heat absorbed cannot be sufficiently absorbed by the heat insulating material on the back surface, and heat dissipation to the indoor side increases. Preferably the R _E of the substrate surface at least 30%, more preferably 40% or more.

The substrate may be any metal plate having the above-mentioned reflectivity, and its type and chemical composition are arbitrary. For example, a low-carbon steel, a high-carbon steel, a steel plate made of a low-alloy steel used for a high-strength steel plate and the like is preferable because it is excellent in economy, but it is not necessary to be limited to these, and a plated steel plate, a stainless steel plate, an aluminum plate It does not matter. From the viewpoint of corrosion resistance, a plated steel plate, a stainless steel plate, an aluminum plate and the like are preferable.

When the substrate is a plated steel sheet, the amount of the plating film attached is arbitrary, but a plating film having a thickness of 0.01 μm or more is preferable because the solar heat reflectivity is improved. The plating method is arbitrary, and any known plating method such as an electroplating method, a hot-dip plating method, a molten salt electrolytic plating method, and a vapor deposition plating method can be adopted.

Surface coating : The heat-insulating building material of the present invention is applied to a surface of a metal substrate having a solar heat reflectance R _E of 20% or more (this surface is directed to the outer surface receiving solar radiation) by 800 to 2100 n.
m in the wavelength region (= near infrared region)
_At least one reflective coating containing 2 to 70% by weight of a reflective pigment having an _{E / NIR} ) of 30% or more.

The reflectivity of the reflective pigment is determined by measuring the solar thermal reflectance (R) in the wavelength range of 800 to 2100 nm, which is the near infrared range.
_{E / NIR} ) is specified because the solar thermal reflectance of the pigment with respect to the wavelength in the visible light region is determined by the color applied to the substrate. If the solar heat reflectance of the pigment is defined to include the wavelength in the visible light region, the degree of freedom of the color of the coating film which determines the appearance of the building material is lost, and the building material is not suitable. According to the present invention, only by defining the solar heat reflectance of the pigment used in the coating film with respect to the wavelength in the near-infrared region, it is possible to reliably impart high solar heat reflectivity to the outer surface of the building material. A heat insulating effect can be obtained.

The pigment contained in the coating film is a reflective pigment having a solar heat reflectance (R _{E / NIR} ) of at least 30% in the near infrared region. If the R _{/ NIR of} this pigment is less than 30%, the solar heat reflectivity of the painted surface on the outer surface of the building material will decrease, and the amount of heat absorbed when receiving solar heat will increase. Since it cannot be absorbed, the heat insulating effect of the building material is reduced. The _{RE / NIR of the} pigment is preferably at least 40%.

To make the coating solar reflective, the reflective pigment is incorporated in the coating in an amount of 2 to 70%. When the content of the reflective pigment in the coating film (the total amount when two or more pigments are used in combination) is less than 2%, the solar heat reflectivity of the painted surface is insufficient and the coloring power is insufficient. However, in order to obtain a desired color, a thick coating is required. The content of the reflective pigment is preferably at least 5%. When the content of the reflective pigment in the reflective coating exceeds 70%, the processability of the coating is impaired. The content of the reflective pigment is preferably at most 60%.

The pigment used for the coating film of the heat insulating building material of the present invention can be arbitrarily selected in consideration of hue, weather resistance, color stability and the like. Among them, metal oxides, sulfides and chromates It is preferable to use a pigment selected from metal compounds such as, for example, insoluble dyes (dye pigments), and lake pigments.

The pigment contained in the coating film need not be limited to one kind, and a pigment satisfying the above conditions can be arbitrarily selected in consideration of hue, weather resistance and color stability. R _{E / NIR} is 30
%, The total content of these pigments should be within the above range.

If the average particle size of the pigment exceeds 50 μm, the solar heat reflectivity is poor. Therefore, the average particle size of the reflective pigment is preferably 50 μm or less. From the viewpoints of stain resistance, weather resistance, and color stability, the average particle size of the reflective pigment is more preferably 20 μm.
The thickness is more preferably 10 μm or less.

The solar heat reflective coating film may contain an extender such as silica, titania and alumina, in addition to the above-mentioned pigments. Even if these substances are contained, the solar heat reflectivity of the coating film is not impaired. When the extender coexists, the adhesion between the substrate surface and the organic resin as a binder (for example, polyester resin, fluorine resin, etc.), the cohesive strength of the coating film itself, and the concealment and brightness of the base are improved. Can be done.

As a binder for retaining a pigment, yellowing, discoloration, reduction in gloss, and chalking are unlikely to occur even when exposed to sunlight. It is preferable to use an organic resin that can be maintained for a period.

As such a resin, an acrylic resin,
Various organic resins such as a polyester resin, a polyolefin resin, and a fluorine-based resin may be used. Any one of them may be used, but a mixture of two or more may be used. The content of these organic resins is preferably in the range of 10 to 90% based on the dry weight of the coating film.

In the resin, thickening agents such as synthetic finely divided silica, organic bentonite, carboxymethylcellulose, polyvinyl alcohol, melamine, benzoguanamine,
A crosslinking agent such as an isocyanate type, a dispersing agent such as a polyacrylic acid, a polyacrylate and the like may be contained.

The thickness of the reflective coating is preferably from 3 to 200 μm. A coating film thinner than 3 μm may not have stable hue. The thickness of this coating film is more preferably at least 10 μm. If the thickness of the coating film exceeds 200 μm, peeling or cracking of the coating film may occur at the time of processing, and a plurality of coating operations are required, resulting in poor economy. Therefore, the thickness of the reflective coating is preferably 200 μm or less, more preferably 30 μm.
μm or less.

When a substrate has a plurality of coating films (for example, undercoating, intermediate coating, and overcoating), one or more coatings can be a reflective coating. In that case, it is preferable that the coating film that determines the color of the painted surface (hereinafter, this coating film is referred to as an outer coating film, for example, a top coating film) is a reflective coating film. The coating of the inner layer may or may not contain a reflective pigment.

The ordinary undercoat or intermediate coat generally contains a pigment that easily absorbs solar heat. When the content of the reflective pigment in the inner layer coating film is less than 2%, the thickness of the coating film is preferably thinner and not more than 200 μm so as not to impair the solar heat reflectivity.

However, one or more inner coating films may contain the above-mentioned reflective pigment in an amount of 2 to 70%, so that the inner coating film can also be provided with solar heat reflectivity. For example, if the outer layer coating is thin or the pigment content is low, and the outer layer coating has low concealing properties, the inner layer coating (e.g., intermediate coating) may be made to be solar reflective so that the solar thermal Reflectivity can be further improved.

Since the inner layer coating has almost no effect on the appearance of the coated metal plate, it is preferable to use a pigment having high solar heat reflectivity regardless of color as the reflective pigment used for the inner layer coating. In that sense, the inner layer coating is highly reflective not only for near-infrared rays but also for visible rays,
30% solar thermal reflectance (R _E ) in the wavelength range of ~ 2100 nm
As described above, it is preferable to use a pigment having a content of 40% or more.

On the painted surface of the heat-insulating building material of the present invention, for example, a paint to be used is mixed with aluminum flakes to form a metallic coating, or a matting agent is mixed to form a matte coating. Arbitrary design can be imparted. The reflective coating is preferably provided on the uppermost layer of the coated metal plate of the present invention. However, as described above, for example, when a metallic coating containing aluminum flakes is used, the reflective coating is optionally provided. A clear layer containing no pigment or a translucent layer containing a small amount of pigment may be provided on the film.
Such a layer is not included in the outer layer.

The above-mentioned coating film may be formed only on the front surface (one surface) of the substrate, but may be similarly formed on the back surface. Although the coating on the back side is costly, if a reflective coating is also formed on the back side, the solar heat reflection as a coated metal plate is further improved, and the amount of solar heat radiated into the room is further reduced. When the substrate is a steel plate, there is also an effect of improving corrosion resistance. However, when painting the back surface, the painting may be different from the front surface.

Back insulation: The insulation disposed on the back side of the heat-insulating building material of the present invention is not particularly limited in the material and the like, and a known insulation can be applied as it is. Examples of the heat insulating material include a foamed resin material such as polyethylene foam, glass wool, and the like, but are not limited thereto. The selection may be made in consideration of various factors such as heat insulation (thermal conductivity), flame resistance, toxicity during combustion, and cost.

The heat insulating material can be fixed to the substrate by any method. It is convenient to attach the heat insulating material to the back surface of the metal substrate by using an adhesive or by heat sealing the heat insulating material itself. However, a method of sandwiching a heat insulating material between two steel plates, such as a double heat insulating folded plate, is also possible. Also, in the step of painting the front surface of the substrate, a paint having a heat insulating effect may be painted on the back surface, and a heat insulating material may be provided. However, the double insulation folding method requires a high construction cost because the construction method is complicated, and the method of coating the backside with a heat-insulating paint requires a thick coating film, which is economically disadvantageous. is there.

The heat insulating building material of the present invention may be provided with the above-mentioned reflective coating on the highly reflective surface of the metal substrate and the heat insulating material on the back surface. Is possible.

For example, in order to further increase the corrosion resistance of the plating film on the substrate, a known chromium treatment layer or a phosphate conversion treatment layer may be provided on the plating film. In that case, in order to not impair the reflectivity of the substrate, in the case of a chromium-treated layer, the amount of adhesion is 200 mg / m ² or less in terms of metal Cr,
In the case of a phosphate conversion treatment layer, the content is desirably 5 g / m ² or less.

Even if the substrate is a stainless steel plate, an aluminum plate, or the like, a known chromate treatment may be applied in order to increase the adhesion to the coating film. Is preferred.

In order to improve the adhesion between the reflective coating film and the substrate and the corrosion resistance, an undercoating made of an organic resin such as an acrylic resin or an epoxy resin may be applied to the surface of the substrate.

Production method : The method for producing the heat insulating building material of the present invention is not particularly limited. A paint containing the above-mentioned reflective pigment and an organic resin as a binder is applied to the surface of the metal substrate having an _RE of 20% or more to form a reflective coating film, and the back surface of the substrate is heat-insulated as described above. By arranging the materials, the heat-insulating building material of the present invention can be manufactured.

The solvent used for the paint is not particularly limited, and may be appropriately selected from conventional solvents in accordance with the organic resin. Examples of the solvent include, but are not limited to, water, toluene, xylene, cyclohexanone, and methyl ethyl ketone. The resin may be dissolved in a solvent or may be dispersed or suspended in a solvent such as an emulsion resin. In the paint,
The above-mentioned extender, cross-linking agent, dispersant and the like can be blended.

The coating method of the paint may be a known method, for example, a method such as spray coating, roll coating, curtain flow coating, bar coating and the like can be applied. After the coating, the resin may be dried by a known method such as a hot air oven or an induction heating oven. If the resin is thermosetting, the resin may be baked to cure the resin, and then cooled. These treatments can be performed using known coating equipment.

Before the coating containing the reflective pigment is applied to the substrate, as described above, the substrate may be appropriately subjected to a pre-coating treatment, an undercoat, an intermediate coating, or a part or all thereof may be omitted. You may. Further, the reflective pigment may be contained in the intermediate coating or the coating for the intermediate coating and the undercoat. Before mounting the heat insulating material on the back side, the same or another coating may be applied.

When attaching a heat insulating material to the back surface of the obtained coated metal plate, the attachment may be performed by a known method. For example, the heat insulating material may be continuously applied while unwinding the coated metal sheet wound in a coil shape. If the heat insulating material is thin, the heat insulating material may be applied, and then the desired building material may be continuously applied. Shape. This method is suitable for economically producing the heat insulating building material of the present invention. However, the bonding of the heat insulating material may be performed after the coated metal plate is formed into a desired shape.

The heat insulating material is desirably disposed on the entire back surface of the coated metal plate. In particular, when the heat insulating material is bonded after the substrate is formed, the heat insulating material is partially disposed on the rear surface of the substrate. It may be left without.

The heat-insulating building material of the present invention can freely color the outer surface, has very little heat radiation to the inner surface (indoor) side even when exposed to solar heat, and has excellent heat insulating properties. Ideal for In addition, if it is manufactured by a method of molding, especially after attaching it to a thin heat insulating material, it is possible to manufacture the formed heat insulating building material with good productivity at a low cost, and a heat insulating material having sufficient heat insulating performance even with a thin heat insulating material. Building materials are obtained.

[0063]

EXAMPLES (Example 1) As metal substrates, the thickness was
0.80 mm hot-dip galvanized steel sheet (GI) specified in JIS-G3302, hot-dip zinc-5% aluminum alloy coated steel sheet (5% Al-Zn) specified in JIS-G3317, specified in JIS-G3321 Hot-dip zinc-55% aluminum alloy plated steel sheet
(55% Al-Zn), an austenitic stainless steel plate (SUS304) specified in JIS-G4305, and an aluminum plate (A1100P) specified in JIS-H4000. Solar thermal reflectivity R _E of each of these substrates in the wavelength region of 350 to 2100 nm
Table 1 shows the result of calculating from the spectral reflectance.

The pigment has a spectral reflectance R _{E / NIR} of 45% in a wavelength region of 800 to 2100 nm and an average particle diameter of 0.4 μm.
Insoluble monoazo pigment [SYNMU, manufactured by Dainippon Ink and Chemicals, Incorporated]
LERFAST YELLOW 4192 (PY154)] (hereinafter “Pigment PY”),
And lead chromate having a RE _{/ NIR} of 15% and an average particle diameter of 0.5 μm (325 Nichrome Seika Kogyo, 325 chrome yellow 7G)
"Pigment 7G") was used. Pigment PY is a reflective pigment, and pigment 7G is a comparative pigment.

20 parts by weight of the above pigment, 80 parts by weight of a polyester resin as a binder, and a melamine cross-linking agent as the remainder of the dry solids are mixed, and an appropriate amount of cyclohexanone is used as a solvent to disperse and mix with a ball mill. Paint was prepared.

Separately, an undercoating paint was prepared in the same manner as the topcoating paint except that the pigment was 40 parts by weight, the polyester resin was 60 parts by weight as a binder, and the others were the same.

These paints were applied to one surface of each of the above substrates by a roll coating method in such an amount that a dry film thickness of 10 μm for undercoating and 20 μm for overcoating was obtained.
Baking was performed at 60 ° C for 60 seconds to obtain a coated metal plate coated on one side only.

A 4 mm-thick polyethylene foam (thermal conductivity λ = 0.04 kcal / mh ² ° C.) was continuously applied as a heat insulating material to the unpainted back surface of the coated metal plate to produce a heat insulating building material. Since the adhesive was applied to both sides of this polyethylene foam in advance, it could be adhered to the substrate only by peeling off the release paper.

As another heat insulating material, glass wool having a thickness of 100 mm (thermal conductivity λ = 0.55 kcal / mh ² ° C.) is used, and the heat insulating material is sandwiched between two metal plates by a double folded plate method. Was prepared. In this case, the above-described coated metal plate was used as the upper metal plate, and the uncoated back surface of the substrate was arranged so as to be in contact with the heat insulating material. As the lower metal plate, the same substrate as the coated metal plate (that is, a substrate not coated on both sides) was used.

A sample having a length of 300 mm and a width of 300 mm was cut out from each of the coated metal plate (surface coating only) before the heat insulating material was placed and the above two types of heat insulating building materials.
As shown in (1), the painted surface was placed on the opening of the thermal insulation container having an opening (outside surface), the opening was sealed, the painted surface was exposed to solar radiation, and the temperature rise inside the thermal insulation container was investigated.

FIG. 1 shows a sample of a painted metal plate having a painted surface 2 formed on one side of a substrate 3, FIG. 2 shows a sample of a coated metal plate on which a heat insulating material 7 is arranged on the back side, and FIG. The case where the heat insulating material 7 is manufactured by the double folded plate method and the sample is sandwiched between the substrate 3 and the metal plate 8 is shown.

In FIGS. 1 to 3, the heat retaining container 6 is configured such that the side walls other than the opening have good heat insulating properties. As described above, a device that follows the solar radiation so that the sample is irradiated outdoors with the sunlight 1 at the same angle in the insulated container 6 whose container opening is sealed with the sample with the painted surface 2 facing upward (FIG. (Not shown). A thermocouple 4 was attached to the back surface of the sample, and the thermocouple 4 was connected to a recorder 5 provided outside to measure a temperature change on the back surface of the sample. The highest temperature reached during this measurement is shown in Table 1 together with the structure of the sample.

[0073]

[Table 1]

As can be seen from Table 1, in a coated metal plate having only a surface coating, the paint contained in the coating is changed from a paint having low spectral reflectance in the near infrared region to a paint having high reflectance. As a result, the amount of heat dissipated to the rear surface side is greatly reduced, and the maximum attainable temperature of the rear surface (hereinafter, the rear surface temperature) is lowered. However, if the surface coating alone is used, the backside temperature will exceed 50 ° C. even if the solar heat reflectivity of the coating film is increased.

On the other hand, a very thin heat insulating material having a thickness of 4 mm is adhered to the back surface of the substrate provided with the reflective coating according to the present invention, and the back surface temperature is reduced to around 50 ° C. or lower. Can be reduced. In the case of such a thin heat insulating material, if the solar heat reflectance of the coating film on the front surface side is low, the back surface temperature becomes higher than around 60 ° C., and the difference in the back surface temperature is obvious. When a heat insulating material such as glass wool with a thickness of 100 mm with a large amount of heat insulation is arranged, the back surface temperature is extremely low even if the coated metal plate has low solar heat reflectivity.
However, even in this case, the higher the solar heat reflectivity of the coated metal plate, the lower the back surface temperature.

As described above, the present invention can be applied to a mass production type relatively inexpensive heat insulating building material in which the heat insulating material is as thin as 10 mm or less, for example, and is continuously formed after the heat insulating material is bonded to the painted metal plate. It can be seen that the properties are particularly high.

[0077]

The heat-insulating building material of the present invention is mainly suitable as a building exterior material such as a roof or an outer wall, and is excellent in lightness and heat-shielding properties required for a roof, and can be colored in any color. Moreover, it is possible to obtain a heat-insulating building material having high productivity, capable of continuous molding, and exhibiting high heat-insulating performance with an inexpensive thin heat-insulating material.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an apparatus for measuring the heat insulating property of a coated metal plate that has been coated on one side.

FIG. 2 is an explanatory diagram similar to FIG. 1 in a case where a heat insulating material is arranged on the back surface of a painted metal plate.

FIG. 3 is an explanatory view similar to FIG. 1 in a case where a heat insulating material is arranged on a back surface of a coated metal plate by a double heat insulating folded plate method.

[Explanation of symbols]

1: sunlight, 2: reflective coating, 3: substrate, 4: thermocouple,
5: Recorder, 6: Insulated container, 7: Insulating material, 8: Metal plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Michiyasu Takahashi 4-33, Kitahama, Chuo-ku, Osaka-shi Within Sumitomo Metal Industries Co., Ltd. (72) Inventor: Sao Chio Matsuo 1-21: Fusocho, Amagasaki City Sumitomo Metal Construction Materials In-house company (72) Inventor Minoru Tomohiro 1-21, Fuso-cho, Amagasaki-shi Sumitomo Metal Construction Materials Co., Ltd.F-term (reference) CB00 CC00B DG06C DJ01C GB07 JD12B JJ02C JN06A JN06B YY00A YY00B

Claims (1)

[Claims] An insulated building material comprising a metal substrate having a painted surface on one side and a heat insulating material disposed on an opposite surface, wherein the solar thermal reflectance of the painted substrate surface in a wavelength region of 350 to 2100 nm is provided. (R _E ) is 20% or more and the painted surface is 800 to 2100 n
Insulation having a heat ray reflection function, characterized by comprising at least one coating film containing 2-70% by weight of a pigment having a solar heat reflectance (R _{E / NIR} ) of 30% or more in a wavelength region of m. Building materials.