JP2001353809A - Thermally reflecting precoated metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a precoated metal plate with high thermal reflecting properties. SOLUTION: A primer coating layer 4 with a dry film thickness of 3-20 μm is formed by applying and baking a resin coating material 1 obtained by adding a rust preventive pigment on the surface of a metallic substrate 2 with a treated surface. Next, a top coat layer 5 consisting of two or more laminar pieces of thermally reflecting layers 6 and 7 is formed on the surface of the primer coating layer 4. Each of the thermally reflecting layers 6 and 7 is finished by applying and baking a coating material obtained by blending 3-20 pts.wt. of a hollow inorganic balloon 9 with an average particle diameter of 20-40 μm for 1,000 pts.wt. of the coating material 1. A hydrophilic agent may be added to the thermally reflecting layer 7. When no hydrophilic agent is added to the layer 7, a contamination-resistant protecting layer is formed on the surface of the layer 7. It is possible to constitute, instead of the two or more laminar pieces of the thermally reflecting layers 6 and 7, the top coat layer 5 of a laminate ply thermally reflecting layer 6 containing the hydrophilic agent or the laminate ply thermally reflecting layer 6 containing no hydrophilic agent and the contamination-resistant protecting layer 8 formed on the layer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-reflective pre-coated metal sheet used for, for example, building materials and home electric appliances.

[0002]

2. Description of the Related Art A pre-coated metal plate is obtained by painting and baking a resin paint on the surface of a surface-treated metal substrate. Usually, a long coiled metal plate is pulled out and roll-painted or baked continuously. And finally wound up into a coil.

[0003] The pre-coated metal plate manufactured in this manner generally has excellent characteristics in terms of design, corrosion resistance, weather resistance, and the like. In some cases, it is desired to have heat insulation.
In that case, conventionally, it has been customary to use a pre-coated metal plate in combination with a heat insulating material.

[0004]

Considering the cost and workability, the heat insulation of the pre-coated metal plate itself is improved by increasing the heat reflectivity of the pre-coated metal plate rather than using the heat insulating material as described above. It is more preferable to do so. However, pre-coated metal plates generally have different heat reflectivities depending on the color of the coating film, and in particular, those having a dark color are more likely to absorb heat and have poor heat reflectivity. It was very difficult to ensure sufficient heat insulation regardless of the situation.

An object of the present invention is to realize a precoated metal sheet having sufficient heat insulating properties and excellent heat reflection regardless of the color of a coating film.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a heat-reflective pre-coated metal plate manufactured by drawing out a coiled long metal substrate, painting and baking it, and finally winding it into a coil. It is applicable and is characterized in that it is configured as follows.

That is, as shown in FIG. 1A, a resin coating containing a rust-preventive pigment is applied on the surface of a surface-treated metal substrate 2 and baked to form an undercoat layer 4 having a dry film thickness of 3 to 20 μm. Is formed on the surface of the undercoat layer 4, and the overcoat layer 5 including the heat reflection layer and the overcoat layer 5 having a dry film thickness of 20 to 100 μm is formed. The heat reflecting layers 6.7 each have a structure in which the heat reflecting layers 6.7 are laminated, and each heat reflecting layer 6.7 contains 3 to 20 parts by weight of a hollow inorganic balloon 9 having an average particle diameter of 20 to 40 μm with respect to 100 parts by weight of the coating material. The painted paint is applied and baked (the invention according to claim 1).

As shown in FIG. 1B, for example, the overcoat layer 5 includes at least two heat reflection layers 6, 7 which are coated and baked on the surface of the undercoat layer 4, and these heat reflection layers 6, 7
Of the heat-reflective layer 7 located at the uppermost layer, and a baking-resistant protective layer 8 having a dry film thickness of 1 to 30 .mu.m.
(The invention according to claim 2). In this case, a hydrophilic agent (not shown) for hydrophilizing the surface of the coating film is blended in the stain-resistant protective layer 8 in order to prevent or suppress the surface of the coating film from being contaminated by raindrops or the like. It is desirable to keep it (the invention according to claim 3). In the case where the contamination-resistant protective layer 8 is not provided on the surface of the heat reflecting layer 7, that is, when the uppermost layer of the coating film is the heat reflecting layer 7, the uppermost heat reflecting layer 7 has a hydrophilic property. It is preferable to add an agent (the invention according to claim 4).

In the above-mentioned heat-reflective precoated metal plate, the lower limit of the dry film thickness of the overcoat layer 5 is set to 20 μm in consideration of providing two or more heat-reflection layers. The lower limit of the dry film thickness of the overcoat layer 5 is set to 10 μm, and then the same means as described above can be employed to impart stain resistance to the coating film surface.

More specifically, for example, as shown in FIG. 1C, a resin paint containing a rust-preventive pigment is applied and baked on the surface of the surface-treated metal substrate 2 to obtain a dry film thickness of 3 to 20 mm.
μm undercoat layer 4 is formed, on the surface of the undercoat layer 4, a heat-reflective precoated metal plate having a dry film thickness of 10 to 100 μm including a heat reflection layer formed on the surface of the undercoat layer 4; Average particle size 2 for 100 parts by weight of paint
A single heat reflection layer 6 formed by coating and baking a paint containing 3 to 20 parts by weight of a hollow inorganic balloon 9 of 0 to 40 μm.
And a contamination-resistant protective layer 8 having a dry film thickness of 1 to 30 μm, which is applied and baked on the surface of the heat reflecting layer 6 (the invention according to claim 5). Also in this case, it is desirable to mix a hydrophilic agent in the stain-resistant protective layer 8 (the invention according to claim 6).

As shown in FIG. 1D, when the contamination-resistant protective layer 8 is not provided on the surface of the single-layer heat reflection layer 6, a hydrophilic agent is added to the single-layer heat reflection layer 6. Constitutes the overcoat layer 5. Specifically, on the surface of the surface-treated metal substrate 2, a resin paint containing a rust-preventive pigment is applied and baked to form an undercoat layer 4 having a dry film thickness of 3 to 20 μm. And a dry film thickness of 10 to 10
In the heat-reflective precoated metal plate having the 0 μm top coat layer 5 formed thereon, the above-mentioned top coat layer 5 is coated with a hollow inorganic balloon 9 having an average particle diameter of 20 to 40 μm with respect to 100 parts by weight of the paint.
Is composed of a single layer of the heat reflection layer 6 formed by baking a paint containing 3 to 20 parts by weight of a compound containing a hydrophilic agent (the invention according to claim 7). That is,
The overcoat layer 5 is composed of a heat reflection layer 6 containing a hydrophilic agent. This kind of heat reflection layer 6 (overcoat layer 5) is prepared by blending a hydrophilic agent into the paint containing the hollow inorganic balloon 9 and baking the paint containing the hydrophilic agent on the surface of the undercoat layer 4. Can be formed by

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically. (1) Metal substrate As a metal substrate, for example, a stainless steel plate, an aluminum plate,
Aluminum-plated steel sheets, galvanized steel sheets, aluminum / zinc alloy-plated steel sheets, and the like can be used. In particular, a 55% aluminum-zinc alloy hot-dip steel sheet is advantageous because it has heat resistance and is inexpensive. The metal substrate is subjected to a surface treatment such as a chromate treatment in a pre-coating process.

(2) Undercoating layer The coating for forming the undercoating layer is a coating containing an epoxy resin, a polyester resin or the like as a main component, and a rust preventive pigment such as strontium chromate is used in an amount of 3 to 100 parts by weight based on 100 parts by weight of the resin. A mixture of 50 parts by weight can be used. The undercoat layer is coated with a roll coater,
The film is baked and dried at 240 ° C. to form a dry film having a thickness of 3 to 20 μm. When the dry film thickness is less than 3 μm,
If sufficient corrosion resistance cannot be obtained for exterior use, and if the dry film thickness exceeds 20 μm, not only will the workability of the coating film be impaired, but also the cost will increase.

(3) Overcoat Layer The overcoat layer formed on the surface of the undercoat layer is a layer containing a heat reflection layer. A single layer of a heat reflection layer containing a hydrophilic agent and a single layer of a heat reflection layer, and a single layer of a heat reflection layer. And a contamination-resistant protective layer laminated thereon. The dry film thickness of the overcoat layer is 20 to 100 μm when two or more heat reflection layers are formed, and 10 to 100 μm when only one heat reflection layer is formed.

(4) Heat Reflection Layer The heat reflection layer constituting the overcoat layer is for improving the heat reflectivity and heat insulation of the coating film. As a paint for forming the heat reflection layer, a paint containing polyester resin, fluorine resin, urethane resin, acrylic resin, epoxy resin, or the like as a main component can be used. These paints may contain a coloring pigment in addition to the hollow inorganic balloon used in the present invention.

The heat reflecting layer is formed by applying the coating containing the hollow inorganic balloon to the surface of the undercoat layer by, for example, roll coating, and baking and drying at a plate temperature of 180 to 270 ° C. At this time, it is advantageous to increase the thickness of the heat reflection layer as much as possible in the range of the dry film thickness of the above-mentioned overcoat layer in order to enhance the heat reflection property and the heat insulation property. In some cases, a dry film thickness cannot be obtained. In such a case, a heat reflection layer is further formed on the surface of the heat reflection layer formed as described above by the same method so that a required dry film thickness can be secured in the entire heat reflection layer.

When only one heat reflection layer is provided, the heat reflection layer has a dry film thickness of 10 to 100 μm, preferably 1 to 100 μm.
It is formed to have a thickness of 0 to 50 μm. 10μ dry film thickness
If it is less than 50 m, the amount of the hollow inorganic balloon in the coating film is reduced, so that sufficient heat reflectivity cannot be obtained, and the dry film thickness is less than 50 m.
If it exceeds μm, the workability of the coating film may not be sufficiently obtained, and if it exceeds 100 μm, the tendency becomes more remarkable. When a contamination-resistant protective layer is provided on the surface of the single-layer heat reflecting layer, the upper limit of the dry film thickness of both layers should not exceed 100 μm.

When two or more heat reflecting layers are provided in consideration of the fact that a single coating may not provide a sufficient dried film thickness, the entire heat reflecting layer (on which the stain-resistant protective layer is provided) The thickness of the heat reflective layer is also set to 50 μm for the reason described above, in which case the dry film thickness is set to 20 to 100 μm. Is preferred.

(5) Hollow Inorganic Balloon In the present invention, it is particularly important that a predetermined amount of hollow inorganic balloon is blended in a coating material for forming a heat reflecting layer in order to secure sufficient heat reflectivity. is there. Specific examples of the hollow inorganic balloon include, for example, a hollow ceramic balloon, a glass balloon, and a shirasu balloon, and among them, the hollow ceramic balloon is preferably used. The material of the hollow ceramic balloon is, for example, silicon boride or alumina silicate.

The hollow inorganic balloon has an average particle size of 20 to
The thing of 40 micrometers is used. If the average particle size is less than 20 μm, sufficient heat reflectivity cannot be obtained. On the other hand, if the average particle size exceeds 40 μm, the hollow inorganic balloon is hollow, resulting in insufficient pressure resistance, and is easily broken by the winding pressure during coiling or the pressing pressure during roll coating.
In addition, it becomes difficult to apply a roll coat in relation to the paint viscosity and the like.

The hollow inorganic balloon is used in an amount of 3 to 2 parts by weight based on 100 parts by weight of the paint for forming the heat reflecting layer before adding the balloon.
0 parts by weight are blended. If the amount is less than 3 parts by weight, the heat reflectance inherent in the hollow inorganic balloon is reduced. On the other hand, if the amount exceeds 20 parts by weight, the processability of the coating film cannot be sufficiently obtained, and the cost is increased.

In the manufacturing process of the precoated metal sheet of the present invention, the hollow inorganic balloon has a pressure resistance of 20 to prevent the hollow inorganic balloon in the overcoat layer from being broken by the winding pressure during coiling or the pressing pressure during roll coating.
0 kgf / cm ² (19.6 MPa) or more is desirable. In addition,
In order to see the relationship between the average particle size and the compressive strength of the hollow inorganic balloon, the compressive strength was measured for two types of average particle sizes (60 μm and 30 μm), and the one with an average particle size of 60 μm was about 30 kgf / cm ² ( 2.94 MPa), average particle size 30
In the case of μm, it was about 700 kgf / cm ² (68.6 MPa).

(6) Hydrophilic agent When the heat-reflective precoated metal sheet of the present invention is used, for example, as an exterior building material, if the coating film surface is contaminated, the coating film surface becomes black, and as a result, compared to the initial stage. The heat reflectivity may be reduced. Therefore, the coating layer forming the coating film surface, specifically, the heat reflection layer (when the stain-resistant protective layer is not provided) or the stain-resistant protective layer (when the stain-resistant protective layer is provided) is hydrophilic. This imparts stain resistance to the coating film surface. In this way, it is possible to prevent a decrease in heat reflectivity due to contamination of the coating film surface, and thus it is possible to maintain the performance for a long period of time.

As a means for hydrophilization, a hydrophilic agent is blended into the above-mentioned paint for forming the heat reflection layer or the paint for forming the stain-resistant protective layer, and the coating film having a hydrophilic group on the surface of the coating film. There can be mentioned a method of forming a structure. In this case, the hydrophilic agent is used in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the paint for forming the heat reflecting layer to be hydrophilized or 100 parts by weight of the paint for forming the stain-resistant protective layer. .
Examples of the hydrophilic agent include a silicate inorganic component such as an alkyl silicate and an organosilicate.

As the former alkyl silicate, those represented by the following general formula can be used.

[0026]

Embedded image

In the above formula, R represents an alkyl group having 1 to 10 carbon atoms, and n represents an integer of 1 or more. In this case, the alkyl group may be either a linear alkyl group or a branched alkyl group. Examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, hexyl, octyl and the like. Particularly preferred are lower alkyl groups having 1 to 3 carbon atoms. Examples of the alkyl silicate include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, dimethoxydiethoxysilane, and condensates thereof. These may be used alone or in combination of two or more.

As the latter organosilicate, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraptoxysilane, tetraphenoxysilane, dimethoxydiethoxysilane, or a condensate thereof can be used. .
Any of these may be used alone, or a plurality of them may be used in combination.

(7) Stain-resistant protective layer When the stain-resistant protective layer is provided, the dry film thickness is 1 to 30.
The stain resistant protective layer is formed by paint baking (plate temperature at the time of baking is 180 to 270 ° C.) so as to have a thickness of 1 μm, preferably 1 to 20 μm. At this time, if a hydrophilic agent is blended in the paint for forming the stain-resistant protective layer as described above, the hydrophilicity is imparted to the stain-resistant protective layer, so that the stain resistance of the coating film surface is improved. , The heat reflection can be maintained for a long period of time.

The paint for forming the stain-resistant protective layer includes:
For example, a paint containing an epoxy resin, a polyester resin, an acrylic resin, a urethane resin, a fluorine resin, or the like as a main component can be used. In order to impart stain resistance to the paint, titanium oxide having photocatalytic activity or the like can be blended in addition to the hydrophilic agent as described above. In that case, if a silicon-based substance (for example, silica), which is a water-containing substance, is used in combination with titanium oxide, a thin water film is formed when exposed to ultraviolet light, so that high hydrophilicity can be provided. Become. Further, as the paint, an uncolored clear paint can be used, but it is not necessarily limited to this. For example, a clear paint containing a color pigment can be used. The stain-resistant protective layer does not contain a hollow inorganic balloon because it is for improving the stain resistance of the coating film surface.

[0031]

In the heat-reflective pre-coated metal sheet of the present invention, since the hollow inorganic balloon is compounded in the heat-reflective layer constituting the overcoat layer, the heat rays such as the sun rays irradiated on the surface of the pre-coated metal sheet are: While being repeatedly reflected on the surface, inside the shell, and even in the central cavity of the hollow inorganic balloon, a part of it is absorbed (that is, converted into thermal energy) by the hollow inorganic balloon, and the other part is reflected to the outside as it is The other portion enters another nearby hollow inorganic balloon, where the reflection is repeated again. And, since a large number of such hollow inorganic balloons having multiple reflectivity are present in a dispersed state in the coating film of the overcoat layer, many of the incident heat rays are eventually reflected to the outside. . These characteristics are
This is particularly noticeable when two or more heat reflection layers are formed on the overcoat layer to increase the thickness of the heat reflection layer as a whole. Thus, according to the precoated metal plate of the present invention, high heat reflectivity can be obtained.

In the above case, when the hollow inorganic balloon is made of ceramic, the hollow inorganic balloon warmed by the incident heat rays secondarily radiates heat energy to the outside as electromagnetic waves of a predetermined wavelength (so-called long-wave radiation). ), So that the heat insulation can also be improved.

The hydrophilicity is imparted to the surface of the coating film by adding a hydrophilic agent to the heat reflection layer or the stain-resistant protective layer.
A self-cleaning effect by rain can be expected. As a result, it is possible to prevent the coating film surface from being blackened by rain dripping marks or the like, so that the above-described heat reflection performance or heat shielding performance can be maintained for a long time.

The average particle diameter of the hollow inorganic balloon is 20 to 4
By setting the thickness to 0 μm, sufficient pressure resistance can be ensured.
The hollow inorganic balloon is not destroyed by the winding pressure during coiling or the pressing pressure during roll coating. Therefore, it can be easily manufactured using a normal continuous coating line for pre-coated metal sheets.

[0035]

(Embodiment 1) FIG. 2 schematically shows a cross-sectional structure of a heat-reflective precoated metal plate according to an embodiment of the present invention. In the heat-reflective pre-coated metal plate 1 of FIG. 2, a 0.4 mm-thick 55% aluminum-zinc alloy hot-dip coated steel plate (hereinafter referred to as a steel plate) is used as the metal substrate 2. On the back surface of the metal substrate 2, a predetermined back coating layer 3 is formed.

An undercoat layer 4 is formed on the surface of the metal substrate 2. This undercoat layer 4 is coated with a roll of a polyester resin paint obtained by blending 28 parts by weight of the rust-preventive pigment strontium chromate with respect to 100 parts by weight of the paint, and baked and dried to have a dry film thickness of 7 μm. It is formed in.

On the surface of the undercoat layer 4, an overcoat layer 5 is formed. In this embodiment, the overcoat layer 5 includes a lower heat reflection layer 6 laminated on the undercoat layer 4 and an upper heat reflection layer 7 laminated on the heat reflection layer 6. It is composed of layers. Both heat reflection layers 6 and 7 are made of paint 100
A polyester resin paint obtained by mixing 10 parts by weight of a silicon boride balloon (hollow inorganic balloon) 9 having an average particle diameter of 30 μm and a white coloring pigment with respect to parts by weight is applied by a roll coater and baked and dried. And the dry film thickness is 30
It was formed so as to be μm.

Next, a method of manufacturing the heat-reflective pre-coated metal plate 1 of this embodiment will be described with reference to FIG.
First, one end of a long metal substrate (steel plate) 2 wound in a roll shape is pulled out and guided to a pre-processing unit 11.
In 1, a predetermined surface treatment such as degreasing, cleaning, and chromate treatment is performed on the metal substrate 2. Next, the metal substrate 2 after the pretreatment is sequentially guided to the undercoating section 12 and the backside coating section 13, and the above-described polyester resin paint for forming an undercoat layer is applied to the surface of the metal substrate 2, and Substrate 2
2 is baked and dried at a plate temperature of 220 ° C. in a first baking furnace 14 to form an undercoat layer 4 having a dry film thickness of 7 μm and a predetermined back coating layer 3 as shown in FIG. Form.

Further, the metal substrate 2 is guided to a first overcoating section 15, and the above-mentioned polyester resin paint for forming a heat reflecting layer is applied on the undercoat layer 4. By baking and drying at a temperature of 230 ° C., a lower heat reflection layer 6 having a dry film thickness of 30 μm as shown in FIG. 2 is formed. Then, similarly, the metal substrate 2 is guided to the second overcoating section 17, and the above-mentioned polyester resin paint for forming a heat reflection layer is applied on the lower heat reflection layer 6, and the third baking is performed. Plate temperature 230 in furnace 18
By baking and drying at ° C., the upper heat reflective layer 7 having a dry film thickness of 30 μm as shown in FIG. 2 is formed, and finally wound up in a roll shape. Thus, the manufacture of the heat-reflective layered precoated metal sheet 1 as shown in FIG. 2 is completed.

Example 2 A precoated metal plate was manufactured in the same manner as in Example 1, except that a gray color pigment was used instead of the white color pigment.

(Example 3) In Example 1, the overcoat layer 5 was composed of one heat reflection layer 6 without forming the heat reflection layer 7 on the upper layer side, and the heat reflection used in Example 1 was performed. Except that the heat reflection layer (dry film thickness: 30 μm) 6 was formed using a coating material in which 4 parts by weight of a hydrophilic agent (here, an alkyl silicate) was mixed with 100 parts by weight of the coating material for forming a layer. In the same manner as in Example 1, a heat-reflective pre-coated metal plate 1 as shown in FIG. The color pigment used for the heat reflection layer 6 is white as in the case of Example 1. In the third embodiment (the same applies to the following fourth embodiment),
Unlike the first embodiment, since the upper heat reflection layer 7 is not formed, the coating step in the second overcoating section 17 and the baking and drying step in the third baking furnace 18 shown in FIG. 3 are omitted.

Example 4 A heat-reflection layer precoated metal plate was manufactured in the same manner as in Example 3, except that a gray color pigment was used instead of the white color pigment.

(Comparative Example 1) In Example 3, except that the hollow inorganic balloon (silicon boride balloon) was omitted from the coating material for forming the heat reflecting layer, and that the coating material did not contain a hydrophilic agent. Manufactured the same precoated metal plate as in Example 3. The color pigment used in Comparative Example 1 was white as in Example 3.

Comparative Example 2 A precoated metal plate was produced in the same manner as in Comparative Example 1, except that a gray colored pigment was used in place of the white colored pigment.

(Performance Test) For each of the heat-reflective precoated metal plates obtained in Examples 1 to 4 and each of the precoated metal plates obtained in Comparative Examples 1 and 2,
The following items were tested.

Heat reflection test (incandescent lamp irradiation test): 2
A 00W incandescent lamp is placed 1 mm from the surface of the pre-coated metal plate.
Irradiation was performed 5 cm apart, and after 20 minutes, the temperature on the back side of the precoated metal plate was measured with a contact thermometer.

Measurement of solar reflectance: JIS-A-575
According to the test method specified in 9-5.4.4 (b), the solar reflectance of each precoated metal plate was determined.

Bending (workability) test (JIS-G-3)
312): Bend 180 ° so that there is a gap of three pre-coated metal plates in between, apply cellophane tape to the bent portion, and peel off (180 ° bending 3T cellophane tape peeling test). The presence or absence of peeling of the film was examined.

Salt spray test (JIS-G-321)
2): 5% salt water was sprayed for 500 hours, and the occurrence of rust or the like was examined.

Accelerated weathering test (JIS-A-141)
5): Irradiation with ultraviolet light of a predetermined wavelength for 1000 hours was performed to examine changes in color and gloss.

Pencil hardness test (JIS-G-331)
2): The surface of the coating film was rubbed with a pencil of hardness H, and the presence or absence of scratches was examined.

(Test Results and Evaluation) Table 1 shows the results of each test.

[0053]

[Table 1]

As can be seen from Table 1, good results were obtained in each of the examples and comparative examples except for the heat reflectivity and the solar reflectivity. The heat-reflective pre-coated metal plates of Examples 1 and 3 had a lower temperature of 6 ° C. to 8 ° C. on the back side as compared with that of Comparative Example 1, which was also white, and the coatings of Examples 2 and 3 were gray. The heat-reflective precoated metal sheet of No. 4 has a lower temperature of 12 ° C. to 19 ° C. on the back side as compared with that of Comparative Example 2 which is also gray. For solar reflectance,
The heat-reflective precoated metal plates of Examples 1 and 3 in which the coating film was white were 11% to 20% higher than those of Comparative Example 1 which was also white, and Example 2 in which the coating film was gray.
The heat-reflective pre-coated metal plate of No. 4 is 9% to 11% higher than that of Comparative Example 2 which is also gray.
Thus, according to the present invention, it is possible to obtain a pre-coated metal sheet having excellent heat reflection properties as compared with a normal pre-coated metal sheet containing no hollow inorganic balloon in a coating film (a general coated steel sheet or a color steel sheet), Moreover, it was confirmed that high heat reflectivity could be ensured regardless of the color of the coating film, white or gray.

In the above embodiment, the average particle size was 30 μm.
In this case, a hollow inorganic balloon having an average particle diameter of 20 μm or 40 μm is used, and substantially the same performance can be obtained.

<Indoor Temperature Test> In order to confirm the effect of applying the heat-reflective pre-coated metal plate of the present invention to the roof of a mini-house, etc., the above-mentioned Examples 1 to 4 and Comparative Example 1
In addition to the heat-reflective pre-coated metal plates according to Examples 2 and 3, the heat-reflective pre-coated metal plates of different colors according to Examples 5 and 6 and the pre-coated metal plates of different colors according to Comparative Examples 3 and 4 (general) Color steel sheets) were manufactured, and the room temperature of a mini-house using these as roof materials and outer wall panels was examined.

(Example 5) In Example 1, the dry film thickness of each heat reflecting layer was 25 μm (the dry film thickness of the overcoat layer was 50 μm).
m), and a heat-reflective pre-coated metal plate was produced in the same manner as in Example 1 except that the ivory color pigment was used.

Example 6 A heat-reflective precoated metal plate was produced in the same manner as in Example 5, except that a gray color pigment was used instead of the ivory color pigment.

Comparative Example 3 A precoated metal plate was prepared in the same manner as in Comparative Example 1, except that the dry thickness of the heat reflecting layer was 50 μm and an ivory color pigment was used.

Comparative Example 4 A heat-reflective precoated metal plate was produced in the same manner as in Comparative Example 4, except that a gray colored pigment was used instead of the ivory colored pigment.

(Survey Details) A 6-tatami box-type mini-house (Yodogawa Steel Works Co., Ltd.) using the heat-reflective precoated metal plates of Examples 5.6 and Comparative Example 3.4. And MH60 type mini-houses) A and B were assembled, and they were placed side by side in a place with little influence of shadows on the factory premises, and the change in indoor temperature on a certain day in early October was examined. . The main specifications of mini-houses A and B are as follows.

-Mini house A: roof (3278 mm x 37)
34 mm) is the heat reflective pre-coated metal plate (ivory) of Example 5, and the outer wall panel is the heat reflective pre-coated metal plate of Example 6 (gray). Height is 2443mm. There are no small windows and outlets.

-Mini house B: roof (3278 mm x 37)
34 mm) is the pre-coated metal plate (ivory) of Comparative Example 3.
And the outer wall panel is the precoated metal plate of Comparative Example 4 (gray). Height is 2443mm. There are no small windows and outlets.

The results are as shown in the graphs of FIGS. As is clear from these graphs, the mini-house A using the heat-reflective pre-coated metal plates of Examples 5.6 and the mini-house B using the heat-reflective pre-coated metal plates of Comparative Examples 3.4. In comparison, the room temperature during the day is low overall. Especially during the day when the sunshine is strong
From time to 15:00, the room temperature of the mini house A is 2 ° C. lower than that of the mini house B as shown in the graph of FIG.
To some extent. From these points, if the heat-reflective pre-coated metal sheet of the present invention is used as a roof material or an outer wall panel of a mini-house, etc., it is possible to suppress an increase in indoor temperature as compared with a conventional one using a general color steel sheet. It can be seen that the electricity usage fee of the cooling device and the like can be reduced by that much.

[0065]

As described above, according to the present invention, since the hollow inorganic balloon is contained in the coating of the heat reflection layer constituting the overcoat layer, regardless of the color of the coating,
Compared to a conventional pre-coated metal plate that does not include such a hollow inorganic balloon, the heat reflectivity and the heat insulation can be improved. In particular, when the overcoat layer is composed of two or more heat reflecting layers, the thickness of the entire heat reflecting layer can be increased, so that higher heat reflectivity can be secured. In addition, when a hydrophilic agent is blended in the uppermost heat reflection layer or when a stain-resistant protective layer is provided on the uppermost layer, it is possible to prevent the coating film surface from being stained black due to raindrops or the like. Therefore, it is possible to avoid a decrease in heat reflection performance due to contamination of the coating film surface for a long period of time, and as a result, it is possible to maintain this kind of heat reflection performance for a long period of time. Thus, according to the present invention, it is possible to realize a precoated metal sheet having excellent heat reflection properties and heat insulation properties suitable as a material for, for example, a roof or a wall of a building or a storeroom.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a specific example of each heat-reflective pre-coated metal plate according to the present invention, and showing a cross-sectional structure thereof.

FIG. 2 is a cross-sectional view schematically illustrating a cross-sectional structure of a heat-reflective precoated metal plate according to Examples 1 and 2 of the present invention.

FIG. 3 is a process chart showing a method for manufacturing a heat-reflective precoated metal sheet according to Examples 1 and 2 of the present invention.

FIG. 4 is a cross-sectional view schematically illustrating a cross-sectional structure of a heat-reflective precoated metal plate according to Examples 3 and 4 of the present invention.

FIG. 5 is a graph showing room temperature changes of mini-houses manufactured using the heat-reflective precoated metal plates according to Examples 5 and 6 of the present invention and the precoated metal plates according to Comparative Examples 3 and 4, respectively. is there.

FIG. 6 is a graph showing a specific portion of the graph of FIG. 5 on an enlarged scale.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pre-coated metal plate 2 Metal substrate 4 Undercoat layer 5 Overcoat layer 6 ・ 7 Heat reflection layer 8 Stain resistant protective layer 9 Hollow inorganic balloon

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4D075 AE03 CA17 CB04 DA06 DB02 DC02 DC18 EC15 EC24 EC35 EC53 EC54 4F100 AA31 AB03A AK01B AK01C AK01D AR00E BA04 BA05 BA07 BA10A BA10D BA10E CA13 CA14B CA30E CC03B DE03B03 EJ03 JJ02C JJ02D JJ10C JJ10D JL06E YY00B 4K044 AA02 AB02 BA10 BA15 BA21 BB05 BB11 BB16 BC02 BC09 BC12 BC14 CA11 CA16 CA53

Claims (7)

[Claims] An undercoat layer having a dry film thickness of 3 to 20 μm is formed by applying and baking a resin paint containing a rust preventive pigment on the surface of the surface-treated metal substrate. Has a dry film thickness of 20 to 100 μm including a heat reflection layer.
m is a heat-reflective pre-coated metal plate on which a top coat layer 5 is formed, wherein the top coat layer 5 has a structure in which two or more heat reflection layers 6 and 7 are laminated. A heat-reflective pre-coated metal plate, which is obtained by coating and baking a paint obtained by mixing 3 to 20 parts by weight of a hollow inorganic balloon 9 having an average particle diameter of 20 to 40 μm with respect to 100 parts by weight of the paint. 2. The overcoat layer 5 includes two or more heat reflection layers 6 and 7 which are applied and baked on the surface of the undercoat layer 4, and a heat reflection layer located on the most upper side of the heat reflection layers 6 and 7. Layer 7
2. The heat-reflective pre-coated metal plate according to claim 1, comprising a stain-resistant protective layer 8 having a dry film thickness of 1 to 30 [mu] m which is painted and baked on the surface of the metal plate. 3. The heat-reflective precoated metal sheet according to claim 2, wherein a hydrophilic agent is blended in the stain-resistant protective layer 8. 4. The heat-reflective pre-coated metal sheet according to claim 1, wherein a hydrophilic agent is blended in the heat-reflective layer 7 located on the uppermost side of the heat-reflective layers 6 and 7 constituting the overcoat layer 5. 5. An undercoat layer 4 having a dry film thickness of 3 to 20 μm is formed on the surface of the surface-treated metal substrate 2 by painting and baking a resin paint containing a rust-preventive pigment. Has a dry film thickness of 10 to 100 μm including a heat reflection layer.
m is a heat-reflective pre-coated metal plate on which a top coat layer 5 is formed, wherein the top coat layer 5 contains 3 to 20 parts by weight of a hollow inorganic balloon 9 having an average particle size of 20 to 40 μm with respect to 100 parts by weight of the coating material. A heat-reflection layer 6 of a single layer formed by applying and baking the applied paint, and a stain-resistant protective layer 8 having a dry film thickness of 1 to 30 μm which is applied and baked on the surface of the heat-reflection layer 6. Features a heat-reflective pre-coated metal plate. 6. The heat-reflective pre-coated metal sheet according to claim 5, wherein a hydrophilic agent is blended in the stain-resistant protective layer 8. 7. An undercoat layer 4 having a dry thickness of 3 to 20 μm is formed on the surface of the surface-treated metal substrate 2 by painting and baking a resin paint containing a rust preventive pigment. And an overcoat layer 5 having a dry film thickness of 10 to 100 μm.
A heat-reflective pre-coated metal plate, wherein the top coat layer 5 is a paint prepared by mixing 3 to 20 parts by weight of a hollow inorganic balloon 9 having an average particle diameter of 20 to 40 μm with respect to 100 parts by weight of the paint. A heat-reflective pre-coated metal plate comprising a single-layer heat-reflective layer 6 and a hydrophilic agent incorporated in the heat-reflective layer 6.