TW201111166A - Precoated metal plate - Google Patents

Abstract

Disclosed are a precoated metal plate having high heat insulation properties and excellent formability, and a formed article of a coated metal. Specifically disclosed is a precoated metal plate wherein at least two coating layers are provided on one surface or both surfaces of a metal plate. The precoated metal plate is characterized in that a first coating layer, which is a lower-side coating layer of the at least two coating layers, is an air bubble-containing layer, and when the volume concentration of air bubbles contained in the air bubble-containing layer is represented by V (%) and the thickness of the air bubble-containing layer is represented by t ([μ]m), the following formulae are satisfied: -0.1t + 57.5 = V = -0.05t + 92.5 and 50 = t = 350. The precoated metal plate is also characterized in that a second coating layer, which is positioned above the first coating layer, is a coating layer that contains a melamine-curing polyester resin or an isocyanate-curing polyester resin, the number average molecular weight of the polyester resin is 10,000-23,000, and the second coating layer has a thickness of 3-30 [μ]m.

Description

VI. Description of the Invention: Technical Field of the Invention The present invention relates to a pre-coated metal sheet having high thermal insulation properties, and an electronic machine manufactured using at least a portion of the pre-coated metal sheet. Background Art Conventionally, a metal plate such as a steel plate or an aluminum plate has been used for a board other than an electronic device such as a computer or a digital home appliance. Such metal sheets are widely used as pre-coated metal sheets because of their design requirements. In recent years, with the spread of computers and the electronic products of home electric appliances, a large number of parts such as motors or electronic components are used as heat sources in such computers or home electric appliances. Since the heat generated by these heat sources is increasing, when the light touches the outer panel of the home appliance, it feels hot and has a problem of being hurt. Conventionally, in order to suppress an increase in the temperature of the outer panel of the home electric appliance, there is a method of providing an opening for heat dissipation or forcibly cooling by a fan. X, also used various heat sink materials or thermal insulation materials. However, methods such as (10) are still insufficient for the case of |X, because there is a need to attach a heat dissipating material or a thermal insulating material, so there is a problem of productivity, cost increase, and the like. Here, even if the temperature of the gold > 1 plate itself rises, as long as the heat of the metal plate is not transmitted to the skin that comes into contact with it, the heat will not be felt and the scald may be of concern. Therefore, in order to make it difficult to convey the heat of the metal sheet to the skin to be contacted and to impart thermal insulation (4) to the surface of the metal sheet, a technique for forming a coating layer containing bubbles having low thermal conductivity on the surface of the metal sheet is disclosed. For example, in Patent Document 1 or Patent Document 2, there is disclosed a technique in which a foaming paint is applied and foamed at the time of heat curing of a paint to contain bubbles. Further, Japanese Laid-Open Patent Publication No. 3 discloses a technique of containing bubbles by coating a coating material in which hollow particles or hot-expandable particles are added. Here, the inventors of the present invention used the technique of the above-mentioned Patent Document 3 to form a layer containing bubbles on a metal plate, and then confirmed the film properties and examined whether it is suitable for the precoated steel sheet. As a result, it has been found that the thermal insulating properties of the inventions of Patent Documents i and 2 are good, but the addition, particularly the stretch formability, is not good. Further, it has been found that the invention of Patent Document 3 can be stretch-molded, but the thermal performance is not sufficient. As described above, neither of the inventions can satisfy the thermal insulation performance and the workability, and the technical system of the pre-coated metal sheet which can simultaneously satisfy the thermal insulation properties and workability pursued by the outer panel of the home electric appliance has not been proposed. CITATION LIST Patent Literature Patent Literature 1: JP-A-2005-131830 Patent Document 2: Japanese Patent Laid-Open Publication No. Hei No. Hei. No. Hei. OBJECTS OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the invention to provide a precoated metal sheet and a coated metal molded article which have high thermal insulation properties and are excellent in workability. 201111166 Means for Solving the Problem The inventors of the present invention have made efforts to review the above-mentioned problems. As a result, as shown in Fig. 1, it has been found that a coating layer containing a large bubble is coated on one surface or both surfaces of a metal plate. , can obtain high thermal insulation properties. Further, as shown in Fig. 2, when the size of the bubble is too large as the thickness of the coating film, the processability or adhesion of the coating film is not good, as shown in Fig. 3, when the size of the bubble is too small, the thermal insulation property is shown. Not good. In addition, the inventors of the present invention have made a review, and as a result, as shown in Fig. 1, the coating layer containing a large bubble is thinned by the surface of the coating film and the upper portion of the bubble, so that it is processed or subjected to a square test or the like. In order to solve these problems, it is considered that the coating layer containing bubbles as the lower layer coating film (first coating layer) as shown in Fig. 4, and the upper layer is further provided thereon. The idea of the coating film (the second coating layer). In addition, it has been found that the thermal insulation property, the workability, and the adhesion of the precoated metal plate which have been considered can be achieved by controlling the film thickness of the undercoat film and the bubble content rate within a certain relationship. Moreover, it has been found that by controlling the resin component of the coating layer (second coating layer) on the upper side and controlling the shape and number of bubbles contained in the coating layer (first coating layer) on the lower side, it is possible to achieve both Thermal insulation properties and processability and adhesion of the upper layer. The invention of the present application is based on the knowledge obtained from such observations. In other words, the gist of the present invention is as follows. (1) A precoated metal sheet having at least two coating layers on one surface or both sides of a metal sheet, wherein the first coating layer on the lower side of the at least two coating layers A bubble-containing layer containing bubbles, wherein when the bubble content of the bubble-containing layer is a volume concentration V (°/〇) and the film thickness is Ι(μιη), the following formula is satisfied: -〇.lt+57.5S VS-0.05t+92_5, and 50$t$350,

S 5 201111166 The second coating layer on the upper side of the first coating layer contains a coating layer of a melamine-curable polyester resin or an isocyanate-curable polyester resin, and the number average molecular weight of the polyester resin is 10,000 to 23,000. Further, the film thickness of the second coating layer is 3 to 30 μm. (2) The precoated metal sheet according to (1), wherein the total film thickness of the first coating layer and the second coating layer is Τ (μιη), and relative to the surface of the coating film When the diameter of the bubble measured in the vertical direction is Rv (pm), there are 20 or more bubbles satisfying Rv2 〇.8T in the width of 10 mm of the cross section of any coating film. (3) The precoated metal sheet according to (1) or (2), wherein the first coating layer and the second coating layer each contain a pigment of the same color. (4) The precoated metal sheet according to any one of (1) to (3), wherein a temperature on a surface opposite to a surface of the metal plate having the bubble containing layer is set at 80 ° C or higher When the temperature is 200 ° C or lower, the total infrared ray emission rate in the region of the measured wave number 600 to SOOOcm·1 is 0.50 or less. (5) A pre-coated metal sheet according to any one of (1) to (4), wherein the surface of the bubble-containing layer is located on the outer panel, at least a part of the outer panel. Outside side. Advantageous Effects of Invention According to the present invention, it is possible to provide a precoated metal sheet and a coated metal molded article which have high heat insulating properties and are excellent in workability. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a precoated metal sheet coated with a coating layer having a large bubble. 201111166 Fig. 2 is a cross-sectional view of a precoated metal sheet coated with a coating layer with respect to a bubble having an excessively large film thickness. Fig. 3 is a cross-sectional view of a precoated metal sheet coated with a coating layer with respect to a bubble having a too small film thickness. Figure 4 is a cross-sectional view of a precoated metal sheet of the present invention. Fig. 5 is a graph showing the relationship between the bubble content of the bubble-containing layer and the film thickness t (pm) in terms of volume concentration. Fig. 6 is an explanatory view showing an outline of an experimental apparatus for measuring the rising temperature. Fig. 7 is an explanatory view showing the structure of a casing used for the test of the contact time and the rising temperature. Fig. 8 is a photograph of a cross section of a coating film portion of the precoated metal sheet of Example N 〇. 4 observed by an optical microscope. I. Embodiment 3 Mode for Carrying Out the Invention Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The precoated metal sheet of the present invention has at least two coating layers on one side or both sides of a metal sheet as a substrate. The "lower" used when referring to the position of the coating layer of at least two layers of the precoated metal sheet refers to the side close to the metal plate, and the "upper" means the side away from the metal plate. Specifically, the coating layer includes at least a first coating layer containing bubbles (hereinafter referred to as "bubble-containing layer") and a polymer polyester resin having a surface layer side laminated on the first coating layer. The laminated structure of the second coating layer (hereinafter referred to as "upper coating"). S- 7 201111166 The bubble-containing layer is characterized in that when the bubble content of the coating film is V (%) by volume concentration, and the film thickness is Κμηι), -0.1t+57.5SVS-0.05t+92.5 is satisfied. And the relationship of 50St$350. As a result of review by the present inventors, it has been found that a good thermal insulation can be obtained by satisfying the relationship between the bubble content rate V (%) of the bubble-containing layer and the film thickness t (pm) of -0.1 t + 57.5 SV and t250. Performance, by satisfying VS-0.05t+92.5, and t$350, the coating film will have good processability as the metal plate is deformed. Fig. 5 is a graph showing the relationship between the bubble content of the bubble-containing layer and the film concentration of V (%) and film thickness ί (μηι). As shown below, in the examples, the polyurethane (i) was used as the binder resin of the bubble-containing layer, and Cellmic CE was used as the bubble admixture type, carbon black as the pigment, and the top coat was set. In the case of 15 μm (Example No. 4, 13 to 31, 39 to 48), the bubble-containing layer film thickness: ί (μιη) and the bubble content rate: V (° / 〇), and is classified into heat. The results of the evaluation of the insulation performance and the results of the evaluation of the workability and adhesion are shown. The meaning of the evaluation mark in the figure is shown in the table below. Evaluation mark Thermal insulation performance Processability adhesion ◎ ◎ 〇 ◎ 〇 ▲ Δ X ◎ X □ 〇 Δ Δ Δ ◎ 〇 Δ 〇氺 X ◎ 201111166 As can be seen from Fig. 5, the bubble content rate range (-0. U+57.5SV$-0.05t+92.5) and the range surrounded by the film thickness range (5〇gtg35〇) can be well evaluated in terms of thermal insulation properties, workability, and adhesion. Here, the film thickness t is obtained by cutting the coating film, filling the resin, grinding it, and smoothing the cross section perpendicular to the surface of the coating film, and observing it by an optical microscope or an electron microscope, and observing 5 places in the range of the width l〇mm The average value obtained after the request. In addition, the bubble content rate V can be obtained by photographing the cross section of the coating film with an electron microscope or the like, and the transparent sheet used for GHP is covered on the photograph, and the green bubble portion is accurately drawn, and then the bubble portion and the other coating portion are cut out, and the mass is measured. Thereafter, V is obtained from the mass ratio at an area ratio = volume ratio '. The occupational bubble content rate v can also be used to observe the average value obtained after the range of 5 widths l〇mm. Further, the total film thickness of the bubble-containing layer of the pre-coated metal plate and the upper coating layer (as will be described later, when there is a layer below the bubble-containing layer, the thickness of the layer below it is not included). (_) When the diameter of the bubble in the vertical direction of the surface of the coating film is Rv, when there are more than 2 or more bubbles satisfying the width of .8T in the width of any coating film section, the surface is formed with moderate unevenness. It can reduce the contact area between the skin and the pre-coated metal plate when the pre-coated metal plate is touched by fingers or the like, and can reduce the heat transmitted to the skin. In addition, the part in contact with the skin is between the surface of the coating film and the steel plate. The area where the heat conductivity is low and the heat is not easily conveyed n can be caused by the air layer formed between the concave portion of the coating film and the skin. By the effect of the phase multiplication, excellent thermal insulation properties can be obtained. Therefore, it is preferable to have 2G or more bubbles satisfying 2〇.8τ in the wide production of any coating film cross section.

9 S 201111166 The emulsion in the layer is straight; & and the quantity is obtained by observing the cross section perpendicular to the surface of the coating film by an optical microscope or an electron microscope, and looking at the average value obtained after 5 observations in the range of the width version m. The adhesive used for the bubble-containing layer can be generally used. For example, a poly resin, a urethane resin, an acrylic eucalyptus epoxy resin, a melamine resin, a gas vinyl resin, or the like can be used. Further, the resins may be of any of a thermoformable type and a thermosetting type. Among them, an amine phthalate resin or a polyester resin having a high ductility and a good adhesion to the poly-lipid coating used for the overcoat layer is preferred as the binder. When using an urethane resin or a polyester resin, the glass transition temperature (Tg) of the resins is preferably -10 to 7 (TC is preferred. When the Tg of the amine acetoacetate resin or the polyester resin is less than -HTC) There is a concern that the film is not sufficiently formed into a film, and when it is more than 7 (TC, since the film hardness is too high, there is a concern that the workability is low. The method of containing the bubble in the bubble containing layer is not particularly limited, and may be, for example, , coating and burning azomethoxamine, azobisisobutyronitrile are equal to an organic foaming agent which decomposes while generating a gas upon heating, or a solvent which is enclosed in a particle by baking, such as microcapsules, etc. In addition, in the bubble-containing layer of the present invention, when a part of the gas generated by the formation of the bubble is removed by the film, the heat-expandable particles which are inflated may be added to the coating material such as the inorganic hollow particles or the organic hollow particles. 'There is a case where a hole is formed on the surface of the film, but since the upper layer is provided on the bubble containing layer, there is no adverse effect on the performance, and there is no particular problem. On the top of the present invention, the melamine hardened polyester is used. tree , 10 201111166 or isocyanate-cured polyester resin as the basic resin. For example, uranium, by controlling the bubble content of the bubble-containing layer, the film thickness, the bubble diameter m, the thermal insulation, the surface processing to some extent However, the present inventors have found that by providing an overcoat layer on the upper layer of the bubble-containing layer, the bubble-containing layer alone does not satisfy the processing property of the object of the present invention, and the desired excellent processability can be obtained. As the base resin, a melamine hardening type polyester resin having a number average molecular weight of 丨0000 to 23 或 or an isocyanate hardening type polyester resin having a number average molecular weight of 10,000 to 23,000 is used as the base resin. The main tree is a poly-resin resin, and the number average molecular weight is limited to 10,000 to 23,000. The polyester resin having excellent ductility and adhesion is used as an overcoat layer to ensure processability, and the polyester resin is limited. The reason for the melamine-curable polyester resin or the isocyanate-curable polyester resin is that a coating film excellent in hardness and ductility can be obtained. When the number average molecular weight is less than loooo, the workability is deteriorated. When the number average molecular weight of the top coat polyester resin is more than 23,000, the workability is deteriorated. Further, when the number average molecular weight of the top coat polyester resin is more than 23,000, The surface of the film is too soft, and the scratch resistance is deteriorated. Therefore, the upper limit is used. The melamine hardening type of the above-mentioned number average molecular weight of 10,000 to 23,000 is contained in the binder resin. The resin or the isocyanate-curable polyester resin can exhibit the effect of improving the excellent workability. The film thickness of the upper coating layer is preferably 3. When the film thickness of the upper coating layer is less than 3 μm, the workability is poor. Not suitable. When applying the smear layer

11 S 201Π1166 When the film thickness is more than 30μηη, it is easy to cause foaming during coating. It is not suitable for cost in terms of cost. When the film thickness of the upper coating layer is larger than the thickness of the claws, it is not possible to control the bubble content. The thermal insulation effect caused by the unevenness of the surface of the coating film formed by the content of the layer bubble is considered. The bubble-containing layer and the overcoat layer of the present invention may be added with a coloring pigment as needed. As the coloring pigment, generally known inorganic pigments, organic pigments, and metallic pigments can be used. For example, carbon black, titanium oxide, zinc oxide, aging red, bisazo yellow 'bisazopyrazole orange, aluminum pigment, nickel pigment, and the like can be mentioned. The colored pigment added to the bubble-containing layer and the overcoat layer is preferably a homologous color. If the bubble-containing layer and the upper coating layer are of the same color, in addition to obtaining a stable color appearance, even if the upper coating layer is thinned or slightly cracked due to processing or the like, the appearance and the color tone can be suppressed, which is preferable. . When the coloring pigment is added to the bubble-containing layer and the top coat layer of the present invention, the amount of the binder is preferably 100 parts by mass or less based on 100 parts by mass of the binder resin. When the coloring pigment is more than 13 parts by mass, the amount of the coloring pigment is too large, the coating film becomes brittle, and there is a possibility that workability and adhesion are poor. The bubble-containing layer and the overcoat layer of the present invention may be added together with an anti-rust pigment or a rust preventive agent as needed. For example, a generally well-known chromium-based rust preventive pigment such as strontium chromate or calcium chromate; or zinc phosphate 亜 亜 phosphoric acid, aluminum phosphate, aluminum phosphite, molybdate, phosphomolybdate, vanadic acid/ Phosphoric acid mixed pigments, cerium oxide, and calcium citrate are commonly known as non-chromium rust-preventing pigments and rust inhibitors such as Ca-type cerium oxide. Among the above-mentioned rust preventive pigments and rust preventive agents, 12 201111166, a non-chromium rust preventive agent which is chromic acid which is not an environmentally burdening substance is preferred. _ ; The bubble-containing layer of the present invention and the phase of the rust-preventing pigment added to the top coat = 10 parts by mass of the binder resin, and the amount of the anti-recording pigment is preferably 10 to 13 G by mass. When the amount of anti-rust pigment added is less than (7) mass ^ "when there is a possibility of resistance to good quality, when the amount of new rust is more than 130 lbs. I", the rust-preventing pigment is applied, and the coating becomes brittle and dense. Sexualized materials. In addition, when the bubble-containing layer and the top coat of the present invention are both added to the above-mentioned pigment and the anti-coffee material, the upper limit of the solid content of the binder resin is set to 100, and the total amount of the pigment is set to 130. The quality is equal to, = good. When the total amount of addition of the S pigment is larger than the amount of the cut, the amount of the pigment is too large, and the coating film becomes brittle, and there is a possibility that the reading and the adhesion are poor. & Again, the bubble-containing layer and the overcoat layer of the present invention may be added as needed. Well known (four) I, pigment dispersant and the like. The type of the additive or the amount of the added force π is not particularly specified and may be appropriately selected as needed. The bubble-containing layer and the overcoat layer of the present invention can be applied by, for example, a roll coater, a roll curtain coater, a water roll coater, a spray coating, or the like, using a generally well-known coating method, and thereafter, As is well known, the heavy material is baked in a sintering furnace 'Example # ', a hot air drying furnace, an induction addition and subtraction, an infrared heating furnace, or the like. It is generally preferable to mass-produce a product in a continuous pre-coated metal sheet manufacturing apparatus called CCL (Continuous Coating Lines). When coating with Ccl, apply the undercoat film by roller coater or curtain coater, and apply it as a curtain:

It is better to apply the upper coating film to S 13 201111166. The curtain coater differs from the roll coater in that it can be applied without lying on the substrate, so the undercoat film (the second coating layer) of the present invention containing the bubbles after the drying of the (four) cloth is dried and hardened. When the upper coating film (second coating layer) is applied by a curtain coater, the coating can be carried out without damaging the bubbles in the lower coating film, and the coating appearance is also beautiful, which is more preferable. When the coating is applied to the upper coating film, the coating is damaged due to the destruction of the bubble-surface in the lower coating film during coating, or the thermal insulation property is impaired, or the appearance of the upper coating film is poor. consider. When using a multi-layer simultaneous coating device called a slanted curtain type curtain, and simultaneously laminating and coating the coating film and the upper coating film under the drying process, the drying hardening step after coating is reduced to 1 In the step, the hardened multilayer can be dried at the same time, so that it is preferable from the viewpoint of energy reduction or production efficiency. The precoated metal sheet of the present invention may be provided with an undercoat film layer which is coated with an anticorrosive coating function under the bubble containing layer. When the undercoat film screen is applied, it is preferable because the corrosion resistance of the metal plate is improved. The undercoat film layer coated on the coated metal plate of the present invention is a well-known undercoat film for precoated metal sheets, and for example, a polyester primer can be used. The ethyl ester is primed and the like. The hardener for the undercoat film may be any of the melamine isocyanate groups. An anti-rust pigment added to the undercoat film. It is generally known that a complex acid system, a scaly acid system, or a silica dioxide system is used, and those other than the complex acid system are preferred because they have a small burden on the environment. The undercoat film applied to the precoated metal sheet of the present invention can be applied by, for example, a transfer applicator, a roll curtain type coating, a water squeezing roll coater, and a spray coating. After coating, the coating is baked, for example, in a hot-air drying furnace, an induction heating furnace, an infrared heating furnace, or the like. The precoated metal sheet of the present invention is set at a temperature of 8 (Tc or more and 20 degrees (a predetermined temperature below TC) in the range of the wave number of 600 to 3000 cm-1 when the surface opposite to the surface having the bubble containing layer is set. The total infrared emissivity is preferably 0.50 or less. When the thermal radiation is incident on the metal plate, the heat radiation is reflected or absorbed due to the fact that there is no heat radiation transmitted. Here, the heat is generated inside the casing. When the heat radiation generated by the body is incident on the inner surface of the outer casing, when the majority of the incident heat radiation is absorbed, the temperature of the outer casing rises. According to the Kirchhof law regarding heat radiation, At a certain temperature, the absorption rate of the object (7) is the same as that of the emissivity (for example, "Mechanical Engineering Fundamental Lectures and Electrothermal Engineering" by Nishikawa and Fujita, p. 290, Issue: Institute of Science and Technology (1983)). The inventors of the present invention have studied the emissivity of the opposite side of the surface containing the bubble in detail, and as a result, it has been found that the temperature of the outer surface of the outer casing can be lowered by lowering the emissivity of the inner surface of the outer surface of the outer cover of the heating element. In other words, Bubble containing layer The opposite surface is the inner side of the casing, and the total emissivity in the wavenumber 6〇〇~3〇〇〇cm-i region measured at a temperature of 8〇〇c or more and 200C or less is set to 0.50 or less. 'It is better to use 〇4〇 or less, and it is found that the temperature of the outer shell plate can be greatly reduced. Less than the wave number, or the wave number area larger than 3_cm_i, because the heat applied to the outer shell of the basket is very small, so it contains The emissivity of these wavenumber regions is better. By limiting the measured wave number to the region of the deletion, the accuracy is good, and the shirt is efficiently measured. 15 201111166 Further, when the temperature of the measured emissivity is less than 80 ° C In the case of measuring the emissivity, it is easy to generate a test error, and it is not suitable. The temperature is 80° C. or higher and 200. (The following temperature is measured, and the measurement can be performed with high precision. The measurement temperature is greater than 200. (: When the film type is thermally decomposed with the type of the film, it is not suitable. In order to improve the heat reflectivity inside the case, when the metal base material has the south heat reflection property, Its exposed Further, it is more preferable to use a metal having a high electric ore-reflecting property on the surface of the metal plate. A metal material having high heat reflectivity can be a commonly known metal material such as aluminum, nickel, stainless steel or zinc, such an alloy, and plating. There is such a metal material. When the film is peeled off without applying a film on the metal plate or the plating layer, the heat reflectance of the surface on the inner side of the casing is further improved, and the steel plate is hot-dip galvanized. Steel plate, electro-galvanized steel plate, galvanized-nickel alloy steel plate, alloyed hot-dip galvanized steel plate, aluminized steel plate, aluminized-zinc alloy steel plate, etc. However, 'when the metal is peeled off, it is easy to be corroded there. Therefore, it is preferable to carry out chemical conversion treatment. However, as the type or amount of chemical conversion treatment is considered to be low in heat-reflecting, it is necessary to appropriately select the type or the amount of adhesion as needed. For the chemical conversion treatment, a general practitioner can be used. Specifically, for example, a phosphoric acid chemical conversion treatment, a non-chromic acid chemical conversion treatment, a coating type chromic acid treatment, an electrolytic chromic acid treatment, a reaction chromic acid treatment, or the like can be used. Among them, the coating type chromic acid treatment, the electrolytic chromic acid treatment, and the reaction chromic acid treatment are not preferable because they contain hexavalent chromium which is an environmental burden substance. In addition, the chemical conversion treatment of the phosphoric acid system also has doubts that the processing adhesion is worse than other treatments. Therefore, the chemical conversion treatment of the metal material according to the embodiment of the present invention is preferably carried out by a non-chromic acid treatment. The non-chromic acid chemical conversion treatment may be any one of those using an inorganic chemical conversion treatment agent and an organic chemical conversion treatment agent. Specifically, the non-chromic acid-based chemical conversion treatment is known, for example, by using an aqueous solution containing a solution such as Shi Xixuan, a wrong compound, a titanium compound, tannin or tannic acid, a resin, or cerium oxide. Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. A well-known technique described in, for example, Japanese Laid-Open Patent Publication No. Hei. No. 2002-266. Further, as the chemical conversion treatment, a commercially available chemical conversion treatment agent can be used, for example, a chromic acid treatment agent "ZM-1300AN" manufactured by 曰本 PARKERIZING Co., Ltd., and a non-chromic acid chemical conversion treatment agent manufactured by PAR本 PARKERIZING Co., Ltd." CT-E300N", a trivalent chromium-based chemical conversion treatment agent "Surfcoat (registered trademark) NRC1000" manufactured by Sakamoto PAINT. The metal plate of the present invention is preferably used as an outer plate of an electronic machine. By using the metal plate of the present invention on an outer panel such as an electronic device, the surface having the bubble-containing layer becomes the outer side, and even when the skin directly contacts the outer surface of the electronic device, it is hard to feel heat and prevent burns. It is better. The electronic device that can use the metal plate of the present invention in at least a part of the outer panel can be, for example, a desktop PC (Personal Computer), a digital home appliance such as a thin television, a car navigation device, an automobile electronic device such as a car AV, or the like. Also, one of the outer panels of portable products such as notebook PCs and mobile phones.

C 17 201111166 Partial use of the metal sheet of the invention. EXAMPLES Next, the present invention will be more specifically described by way of examples, but the constitution of the present invention is not limited to the following examples. (Example 1) First, the paint used in the present example will be described in detail. In the present embodiment, the surface of the metal plate is formed by sequentially depositing a bubble containing layer (first coating film layer, hereinafter also referred to as "lower layer coating film") and an upper coating layer (second coating film layer) on the side of the metal plate. In the following, the two-layer structure of the "upper coating film" is also applied, and the inside of the steel sheet is not coated or formed with an inner coating film. Hereinafter, the coating composition to be used will be described in the order of the coating material for the bubble-containing layer (hereinafter referred to as "lower layer coating material"), the coating material for the top coating layer (hereinafter referred to as "upper layer coating material"), and the coating material. First, the undercoat layer will be described in detail. By adding a closed isocyanuric acid "Desmodur (registered trademark) BL1100" manufactured by Bayer Urethane Co., Ltd. to "DESMOPHEN (registered trademark) 1150" which is a polyol of Bayer Urethane Co., Ltd., the solid content ratio is a polyol. : Blocked isocyanate = 66: 34, and a clear coating (hereinafter referred to as "amine ethyl ruthenate (i)") was prepared. In addition, isophorone was used as a solvent. As the basic resin, "VYLON (registered trademark) 600" (number average molecular weight: 16,000) of the amorphous polyester resin manufactured by Toyobo Co., Ltd. was used. As the crosslinking agent, a butylated melamine resin "SUPER BECKAMINE (registered trademark) J830" manufactured by DIC Corporation (hereinafter referred to as butylated melamine 18 201111166 amine) was used. (The table is marked as "polyester"). In addition, the solvent is mixed with cyclohexanone: Solvessol 50 = l: 1. As the other basic resin, "EPICLON (registered trademark) P-439" manufactured by DIC Corporation was used. As the crosslinking agent, butyl melamine "SUPERBECKAMINE (registered trademark) J830" manufactured by DIC Corporation was used. (The table is marked as "epoxy"). In addition, the solvent is mixed with cyclohexanone: Solvessol 50 = l: 1. In addition, as the other basic resin, acrylic resin "ACRYSET (registered trademark) AST-5531" manufactured by Nippon Shokubai Co., Ltd. was used. As the crosslinking agent, a butylated melamine resin "SUPER BECKAMINE (registered trademark) J830" manufactured by DIC Corporation (hereinafter referred to as butylated melamine) was used. (The table is marked as "acrylic acid") ° Another:: The granules are mixed with cyclohexanone: S〇lvessol 50 = l : 1 . Then, with a blender, thermometer, nitrogen tube, and condenser! In a liter four-necked flask, 1 part by mass of phthalic anhydride, 57 parts by mass of neopentyl glycol, and 48 parts by mass of trimethylolpropane were added, and the mixture was stirred at 210 while being nitrogen. (: The condensation reaction was carried out, and the water was distilled off. Then, 531 parts by mass of ε-caprolactone was added and cooled to 100 Torr. After heating for 3 hours, it was cooled to 1 〇〇〇c, and added to 78. A part by mass of cyclohexanone, a synthetic polyol. The blocked isocyanate "Smodur (registered trademark) BL3175j, manufactured by Bayer urethane, was added to the synthesized polyol to make the solid content ratio polyhydric alcohol: blocked isocyanate = 66 : 34, Production of clear paint (in the table, "Amino formate (S) (6)"). In addition, the use of isophorone as a solvent. The solid content concentration of the coating 19 201111166 can be tested in the bubble content, paintability, After the storage stability, the foaming agent "(10) (registered trademark) CE" and the hollow granules made by GANZ Chemical Industry Co., Ltd." are used in the air/bag. "Yi Qing (10) GMH-850" Among the coloring pigments, the black pigment is a carbon black "TOKABLACK (registered trademark) #735〇" manufactured by Tokai Chongb〇n Co., Ltd., and the white pigment is a oxidized capsule "TIpAQUE white" manufactured by Ishihara Industry. (Login trademark) CR-95" and commercially available oxygen Zinc, blue pigments use commercially available etched acid and Laiqing, red pigments use commercially available iron oxide and cinnabar 0 20 2011H166 Additive pigment 1J φί _ — ΙΠ __ χΠ 1—< ---- un Cellmic CE 3 丨 carbon black \ 15 Cellmic CE 4 1 carbon black \ 15 \ Cellmic CE 5 carbon black \ 15 Cellmic CE 10 carbon black \ 15 Cellmic CE 15 carbon tired, \ \5 \ Cellmic CE 20 carbon black 15 \ Cellmic CE 30 carbon tired, 15 Cellmic CE 40 affliction, \ \5 \ Cellmic CE 70 carbon black 15 \ Cellmic CE 140 carbon black \ 15 \ - m m-m -< mm τ-Η Ο m 00 (N (N / 寸 τ Η Ό Cellmic CE 3 Carbon Black Cellmic CE 3 Breaking Black Cellmic CE 3 Breaking Black Cellmic CE 3 Carbon Black Carbon Black Oxidation Chin 1 Lu Sodium Bismuth Diqing 1 Zinc Oxide Iron Oxide Cinnabar [Mass] type 0.3 carbon black 1 0.5 carbon black 1 ι carbon black 2 carbon black Ganzpearl 7 ς GMH-850 n Cellmic CE 3 Cellmic CE 3 Cellmic CE 3 Cellmic CE 3 Cellmic CE 3 Cellmic CE 3 Cellmic CE 3 1 blistering agent Type Cellmic CE Cellmic CE ' Cellmic CE Cellmic CE 5 St ♦1 back to 〇〇Ο Ο 〇o Ο Ο 〇〇〇〇 〇100 100 100 1 100 | 100 100 100 100 100 100 100 (N 100 100 100 100 100 100 100 Adhesive Resin Type® - 智 S- 粜'' Ϊ 绖&- ϊ 潜 s- 智 &- —-, Potential δ- 绪智6- rn 馁3 S- , —, Latent δ- 0 毽S- m δ- >C3 m 6- •3 ί 毽S- 淫 polyester acrylate s ·— » —Η N—✓ am «3 ®- 聚polyamine formate (i) .3 6- /-N «Γ s- m 毽s- .0 m ®- s • —H m Spectrum 6- i s- N • iH ® r s- Coating Type Lower Layer-1 Lower Layer-2 Lower Layer-3 Lower Layer-4 Lower Layer-5 Lower Layer-6, Lower Layer-7 Lower Layer-8 Lower Layer-9 Lower Layer-10 Lower Layer-11 Lower Layer-12 Lower Layer-13 Lower Layer -14 lower layer-15 v〇1 lower layer-17 oo 1 (jar lower layer-19 lower layer-20 1 t^or lower layer-22 lower layer-23 lower layer-24 lower layer-25 lower layer-26

S 21 201111166 Next, the top coat is explained in detail. For the basic resin, the amorphous polyester resin "VYLON (registered trademark) 660" (number average molecular weight 8000), "VYLON (registered trademark) GK250" (quantitative average molecular weight 10000), and "VYLON (registered trademark)" manufactured by Toyobo Co., Ltd. are used. GK140" (number average molecular weight 13000), "VYLON (registered trademark) 240" (number average molecular weight 15000), "VYLON (registered trademark) 600" (number average molecular weight 16000), "VYLON (registered trademark) 280" (quantity average Molecular weight: 18,000), "VYLON (registered trademark) 245" (number average molecular weight: 19,000), "VYLON (registered trademark) 103" (number average molecular weight: 23,000), and "VYLON (registered trademark) 550" (number average molecular weight: 28,000). For the cross-linking agent, a butylated melamine resin (hereinafter referred to as butylated melamine) manufactured by DIC Corporation, "SUPER BECKAMINE (registered trademark) J830", and an isocyanic acid-made compound "Desmodur BL3175" manufactured by Bayer Urethane Co., Ltd. (trade name)" (HDI in the table). The solvent is mixed and used in a mass ratio of cyclohexanone: Solvessol 50 = 1 : 1 0 The coloring pigment is the same as the lower coating. 22 201111166 Adding amount of pigment [parts by mass] (solid fraction) ^Η IT) in 〇〇(N CN Η 1 〇 inch 1-4 inch VO type carbon black carbon black carbon black carbon black carbon black r Yamada sarcophagus black carbon black Carbon black carbon black carbon black oxidation drink in Lu acid: copper indigo 1 zinc oxide iron oxide cinnabar crosslinker addition amount [parts by mass] (solids) type butylated melamine butylated melamine butylated melamine butyl Melamine butylated melamine butylated melamine butylated melamine butylated melamine butylated melamine HDI butylated melamine butylated melamine butylated melamine butylated melamine butylated melamine butylated melamine butylated Melamine main resin addition amount [parts by mass] (solid content) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Number average molecular weight Μ 8000 10000 13000 15000 16000 18000 19000 23000 28000 16000 15000 15000 15000 15000 15000 15000 15000 Type 660 GK250 GK140 240 600 280 245 103 550 600 240 24 0 240 240 240 240 240 | Upper layer-1 Upper layer-2 Upper layer-3 | Upper layer-4 | Upper layer-5 | Upper layer-6 | Upper layer-7 | Upper layer-8 Upper layer-9 | Upper layer - ίο | Upper layer -11 | 12 |Upper-13 1Upper-14 |Upper-15 Upper Level-16 Upper Level-17

S 23 201111166 The inside paint is made of the "FL100HQ" of the paint from the company "Fine Coatings" (the table is marked as "inside seven" and "fu〇〇Hq" is transparent (in the table, it is "inside-2"). Hereinafter, the precoated metal sheets used in the experiments of the examples will be described in detail. Prepare galvanized steel sheets (denoted as "EG" in the table), hot-dip galvanized steel sheets (denoted as "GI" in the table), alloyed galvanized steel sheets (denoted as "ga" in the table), and stainless steel (denoted in the table) "SUS"), aluminum plate as the original board. Next, the prepared original plate was made into an alkali degreasing liquid "FC-4336" manufactured by Japan PARKERIZING Co., Ltd. at a concentration of 2% by mass and 5 Torr. (:Aqueous solution spray degreasing, washing with water, drying, and coating "CT-E300N" by chemical conversion treatment of non-complex acid manufactured by PARKERIZING Co., Ltd. by a roll coater, and drying it in a hot air oven. Drying conditions in a hot air oven The arrival sheet temperature of the steel sheet is 60 ° C. The adhesion amount of the non-chromic acid treatment is applied to adhere to the whole solid content of 200 g / m 2 . Then, the undercoat is simultaneously prepared by the applicator It is coated on one side of a metal plate subjected to chemical conversion treatment, and the inner coating material is coated on the other side, and then dried and hardened by an induction heating furnace blown with hot air at a plate temperature of 220 ° C. Further, after drying and baking, water is sprayed onto the coated metal plate by a sprayer to perform water cooling. Next, the upper layer coating is applied to the lower coating film by a roll curtain coater, and hot air is blown therein. The induction heating furnace is dried and hardened under the condition that the sheet metal reaches a plate temperature of 230 C. Further, after drying and baking, water is sprayed onto the coated metal plate by a sprayer, and water-cooled to produce a 2-layer layer. Pre-coated gold 24 2011111 66. The following is a description of the details of the evaluation method of the precoated metal sheet produced in the experiment. 1. Thermal insulation performance 1.1 The use of the contact time and the rising temperature of the hot plate is used to make the surface on the upper side. The coated metal plate was placed on a hot plate heated to 65 ° C for 120 seconds, and then a load of 500 g was applied to the surface of the precoated metal plate with the index finger, and the contact time without feeling of heat was measured, and the following The evaluation was carried out on the basis of the same test, and the same test was carried out for five people, and the average time was used for evaluation. (The table indicates "thermal insulation performance (i)".) ◎ : 10 seconds or longer 〇: 5 seconds or longer Less than 10 seconds Δ : 2 seconds or more and less than 5 seconds X : Less than 2 seconds Further, an outline of the experimental apparatus for measuring the rising temperature is shown in Fig. 6. The precoated metal sheet which is prepared by the surface on the upper side is prepared. Placed on a hot plate heated to 65 ° C for 120 seconds, and then thermocoupled between the silicone rubber (thickness 3mm, side length 10mm square) is attached to the surface of the pre-coated metal plate lg / Mm2, the temperature after 30 seconds is measured, and the following The evaluation is carried out. (The table is labeled as "Thermal insulation performance (ii)".) This is a test in which helium oxide rubber is used as a skin to simulate the heat felt by a person. ◎: Less than 35 ° C 〇: 35 ° C The above is less than 37 ° C Δ : 37 ° C or more and less than 39 ° C x: 39 ° C or more 1.2 Measurement The contact time and the rising temperature of the casing were used to prepare the casing as shown in Fig. 7 and the test was carried out. It is open, and the open surface is coated so that the inside of the prepared precoated metal sheet is S. 25 201111166. In this state, the heat of the heat source is set to 15 W, and 120 woms are placed. In the same manner as the crucible, the load of 5 〇〇g was applied to the surface of the precoated metal sheet by the index finger, and the contact time of the heat was not measured, and the evaluation was performed on the following basis. In addition, the same test was carried out for 5 people, and the average time was used for evaluation. (In the table, it is marked as thermal insulation performance (iii).) ◎: 10 seconds or more 〇: 5 seconds or more and less than 10 seconds Seconds or more is less than 5 seconds X: Less than 2 seconds 2. Processability The s parity is a cylindrical drawing processability as follows. It is carried out under the conditions of punching straight 5 〇mm, punch shoulder (punch shoulder ORJmm, die shoulder R3mm, draw ratio 2 〇, bhfu, and processing until the steel plate is stretched by the mold) and based on the following进行. Visually observed that there are no cracks or discoloration in the processed part. 〇: Visually observed that the processed part has no cracks, but there is discoloration. △: Visually observe the slight cracking of the processed part X. Visually observing the case where the processed part has a large crack. 3. Adhesion 'The adhesion is measured by the checkered tape test. According to JIS K 5600-5-6, the square tape test is carried out, and the following criteria are used. Evaluation: 〇.There is no peeling of the element. 0: It is found that there is some slight peeling at the edge of the square. Λ: The case where 80% of the square remains unpeeled. Χ The case where the square is not separated and the residual square is less than 80%. 4. Pollution resistance 26 201111166 Evaluation of stain resistance' was investigated for the following resistance to magic ink stain resistance. The prepared precoated metal sheet was cut into a side length of 50 mm and evaluated. The face is in red imagic ink Draw three lines, and then place them in an ambient gas of 2 ° ° C for 24 hours, then wipe the lines with ethanol. The residual color of the ink is visually judged and evaluated on the basis of the following: ◎ • The ink trace disappears. The situation 〇: the case where the ink trace remains in a small amount △: the case where the ink trace remains X: the case where the ink trace does not disappear. 5. The scratch resistance is determined by the wrong pen hardness. The method of #JIS κ 5600_5_4 is the standard. 'The scratch resistance of the coating film was investigated by the crack of the coating film when the hardness of the wrong core was changed, and the highest hardness which was not found in the coating film was evaluated as the pencil hardness of the coating film by the following criteria. ◎ . HB The above 〇: B △ : 2B X : 3B or less 6. The emissivity in the measurement was measured using a Fourier transform infrared spectrometer "VALOR-ΠΙ" manufactured by JASCO Corporation, and the plate temperature a of the surface-treated metal plate to be produced was measured to be 80. In the case of C, the infrared luminescence spectrum in the region of the wave number 600 to 3000 cm·1 is compared with the luminescence spectrum of the standard black body to determine the total emissivity of the surface-treated metal plate. In addition, the standard black system is used. The iron plate was coated with a "THI-1B black body sprayer" sold by TACOS JAPAN Co., Ltd. (manufactured by OKITSUMO Co., Ltd.) having a film thickness of 30 ± 2 μm. 27 S. 201111166 The present embodiment is shown in Tables 3 and 4. The composition of pre-coated metal sheets produced in China and its evaluation results. 28 20111Π66

201111166 Scratch resistance <] <] <] ◎ ◎ Pollution resistance ◎ ◎ ◎ ◎ ◎ <<<]<]<] Ο -δ H si <1 < 0 <1 &lt Thermal insulation performance ◎ ◎ ◎ 〇 ◎ 〇 ◎ ◎ 〇 ◎ 〇 JS3 Ξ ^ Vg ®. ^ ^ > ώ ί^) 00 Ο Upper coating film main resin Μ 16000 16000 16000 16000 16000 Ο (Ν 9? 〇ο § ο § 〇jrj ο jq -0.lt +57.5 oi •ο <Ν in iTi (Ν (Ν (bubble content (% by volume) Ο 膜 film thickness after drying (μηι) upper film> 〇« η (Ν ΐτ» lower coating 沄cn 沄 upper coating type upper layer-5 I upper layer-5 upper layer-5 upper layer·5 upper layer _5 lower layer coating type! lower layer-5 lower layer-5 lower layer-5 lower layer-3 lower layer-19 original plate Type α ω 〇 ω 〇 [Jj α ω α UJ g < Ν cn ν〇 201111166 ♦ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 〇〇〇〇 ◎ ◎ ◎ ◎ 〇〇〇|@ |@| |@| |@| |@| |@| |@| |@| |@| |@| Η |@| |@| |@ @@ |@@ Μ |@| Θ |@ Η Η Μ |@| Μ ι ι@ι Μ Η Η Ν Η Η Ν Ν Ν Ν 00 inch 00 inch 00 inch 00 inch 00 inch bud ° ° 吋00 inch 00 inch 00 inch 00 inch 00 inch 00 inch 00 inch 00 inch 00 吋 00 inch 00 inch (SW learning ^"wl-o^w^ ^^εεοι «磁# 000-000-000-000-000- 000-000-000-000-000-go-000-000-000-01 000-000-000-i Chain 钿!ΓΓ s+ 1 -300 •3S •s •ss •s •s -300 3 •38 3 • s • s • s • s • • s • • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • £ε · Bu ε Bu ε 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 (% of you 锲) - - - - - - - - - - - - - - - - -

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(1) Effect of the molecular weight of the upper coating film The influence of the molecular weight of the upper coating film is shown in the examples of NO. 1 to 12, and the comparative examples are shown at ^0.37 and 38. The precoated metal sheet of the embodiment of the present invention has excellent thermal insulation properties, workability, adhesion, stain resistance, and scratch resistance. The molecular weight of the upper coating film is 10,000 (NO.l) is processability, and the molecular weight of the upper enamel film is 23,000 (ΝΟ·7). The stain resistance and scratch resistance tend to be slightly lower. The molecular weight of the membrane is 13,000 to 19000 rpm. Those with a molecular weight of less than 10,000 (Ν0.37) are uncomfortable due to poor processability. The molecular weight of the upper coating film is more than 23,000 (ΝΟ.38), which is not suitable due to the pollution resistance and the poor resistance of the & J wave. (2) Relationship between the concentration of the bubble and the film thickness of the undercoat film The relationship between the bubble concentration and the film thickness of the undercoat film is shown in the examples of N0.13 to 31, and the comparative examples are shown in Nos. 39 to 48. The precoated metal sheet of the embodiment of the present invention has excellent thermal insulation properties, workability, adhesion, stain resistance, and scratch resistance. The bubble contains the concentration V volume (%) and the film thickness t (pm), V6 〇 lt + 57.5 (N0.39, 41, 43, 45) is the thermal insulation performance, and V > - 〇. 〇 5t +92.5 (NO.40, 42 '44, 46) is not suitable for poor workability and adhesion. Further, those having a film thickness of less than 50 μm (N0.47) are thermally insulating, and those having a film thickness of more than 350 μm ((48) are unsuitable for poor workability and adhesion. (3) Effect of film thickness of the upper layer coating film 201111166 The influence of the film thickness of the upper layer coating film is shown in ΝΟ32 to 36, and a comparative example is shown in NO. 49 to 51. The precoated metal sheet of the embodiment of the present invention has excellent thermal insulation properties, workability, adhesion, stain resistance, and scratch resistance. When the film thickness of the upper coating film is 3 μm (N0.32), the processability, the adhesion, and the scratch resistance tend to be slightly lower, and the film thickness of the upper coating film is the cost of the Kawaguchi claw (ΝΟ·36). Some tend to be slightly higher, so the film thickness of the upper coating film is preferably 5 to 25 μm. In addition, those having no upper coating film (Ν0.49) and the upper coating film having a film thickness of less than 3 μm (ΝΟ.50) are inferior in workability, adhesion, and scratch resistance, and the film thickness of the upper coating film is larger than 3〇μιη (Ν0·51) is not suitable because of the high cost. (4) Relationship between bubble diameter and total film thickness The relationship between the cell diameter and the total film thickness is shown in Fig. 5 2 to 5 6 . The relationship between the bubble diameter Rv (μπι) measured in the vertical direction of the coating film surface and the total film thickness μ(μιη) of the lower coating film and the upper coating film is satisfied by the width of 10 mm of any coating film section. Rvg〇.8T has less than 20 bubbles (Ν〇·54, 56). 'There is a tendency for the thermal insulation properties to be slightly lower. Therefore, it is known that the bubble of 5^^〇8丁 is 2〇 in any section l〇mm. More than one is better. (5) Effect of the pigment of the lower coating film and the upper coating film The influence of the pigment of the lower coating film and the upper coating film is shown in N〇 57 to 74. The lower coating film is the same as the coloring pigment of the upper coating film (> Ο 57 57~6 〇), the lower coating film and the upper coating film are not containing the coloring pigment (ΝΟ·61), the lower coating film and the upper coating film. The coloring pigments are the same color (ΝΟ·62, 63, 68-71), and the processing properties are excellent. On the other hand, the lower layer is coated with the film of the 201111166 film and the color of the upper layer coating film (N〇64~67, 72 to 74) Since the processing portion visually recognizes that some microscopic discoloration has a problem of low workability, the pigment of the lower layer coating film and the upper layer coating film is preferably the same color. (5) Effect of Emissivity in the Inside The effect of the emissivity in the inside shows an example in N〇%~08, and a comparative example in NO.69. The lower the emissivity in the inside, the better the thermal insulation performance is. It is preferable that the emissivity in the inside is 0.50 or less. Further, it is also known that even if the emissivity is low inside, the surface of the present invention is inferior in thermal insulation performance (N〇 79). (Example 2) The precoated metal plate of Example ΝΟ73 and Comparative Example 表79 of Table 6 was used as a thin TV rear panel, and (10) was inside, and touched by the index finger 2 hours after the display screen The rear panel measures the contact time. In addition, the experiment is the same for 5 people. In addition, in the same manner, the galvanized steel sheet was processed into a shape of a rear panel, and the foamed polyethylene sheet "FOAM ACE (registered trademark) SN_500" manufactured by Furukawa Electric Co., Ltd. was pressed. Any of the testers was exposed to N0.73 for more than 丨 minutes, but the contact time at N0.79 was less than 5 seconds. Further, the foamed polyethylene sheet is attached for one minute or more, but it requires a bonding time and also impairs the appearance, which is not preferable. (Example 3) The precoated metal sheet of No. 4 in Table 3 was coated with a lower layer coating by a pro-applicator, and dried and hardened by water in an induction heating furnace with hot air.

S 35 201111166 The upper coating film is applied by a roll curtain coater, and dried in an induction heating furnace with hot air to dry and harden it, and water-cooled. It can also be made in the same manner by different coating methods. The undercoat film was applied by a grain curtain coater and dried and hardened, and then a precoated metal plate was formed by coating a top coat film with a roll curtain coater as No. 87. No. 87 was prepared under the same conditions as No. 4 except for the coating method. Further, at the same time, a multi-layer simultaneous coating apparatus called a slanted-plate curtain coater is used to laminate the lower coating film and the upper coating film, and the induction heating furnace in which the hot air is blown reaches the sheet temperature of 230 C. At the same time, the laminated film was dried and hardened and then water-cooled, and the precoated metal sheet thus produced was designated as No. 88. The precoated metal sheet of Νο·88 was prepared under the same conditions as those of Νο·4 except that the upper coating film and the lower coating film were applied by a slanted curtain curtain coater at the same time and simultaneously baked. In addition, a pre-coated metal sheet which was formed by coating the upper layer with a light curtain curtain coating and drying it, and applying the upper coating film by a roll coater, was used as NQ·89. Ν〇·89 was prepared in the same manner as No. 4 except for the coating method. The heat-insulating force described in (Example 1) was evaluated on the prepared pre-coated metal sheet, and the evaluation of the resistance, the adhesion, the stain resistance, and the scratch resistance was determined by β N〇87 ^, 〇. 8 8 And N described in Table 3. The results of the evaluation tests of 4 were completely the same as the flat mussels to the fruit, but the evaluation results of the thermal insulation properties 1 and 2 of No. 89 were Δ, which was slightly lower than kN0.4. When the upper film is applied by roll coating, the roller is coated with the lower layer of the coated bubble (4), so the thermal insulation performance is not good. Moreover, Μ 〇, 4, 87, 88 are beautifully painted, but the upper layer of Ν〇 89 is coated with a mottled pattern. It is presumed that this is also a when the roll coating is applied. 36 201111166 The surface is coated with a roller to crush the lower coating film - the surface is cracked, so that the base is uneven; the completion step of the upper coating film becomes (4) As a result, it can be seen that the coating of the invention is preferably coated by a curtain coater. Further, in Fig. 8, a photograph of a cross section of the coating film portion of the precoated metal sheet of Example n〇4 was observed with an optical microscope. The above is a preferred embodiment of the present invention, but the present invention is not limited by the above. It will be apparent that various changes and modifications may be made without departing from the scope of the invention as described in the appended claims. Technical scope. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a precoated metal sheet coated with a coating layer having a large bubble. Fig. 2 is a cross-sectional view of a precoated metal sheet coated with a coating layer having an excessively large bubble. Fig. 3 is a cross-sectional view of a precoated metal sheet coated with a coating layer with respect to a bubble having a too small film thickness. Figure 4 is a cross-sectional view of a precoated metal sheet of the present invention. Fig. 5 is a graph showing the relationship between the bubble content of the bubble-free layer and the volume; and the agricultural product is V (%) and film thickness ί (μιη). Fig. 6 is a view showing an outline of an experimental apparatus for measuring the rising temperature. Fig. 7 is a view showing a test for contact time and rising temperature.

S 37 201111166 An explanatory diagram of the structure of the casing. Fig. 8 is a photograph of a cross section of a coating film portion of the precoated metal sheet of Example N 〇. 4 observed by an optical microscope. [Main component symbol description] 1.. .Hot plate 4...Hot electricity 2.. Pre-coated metal plate 5...Heat source 3..矽Oxygen rubber 6...Temperature controller 38

Claims (1)

201111166 VII. Patent Application Range: 1. A pre-coated metal sheet, which is a coating layer having at least two layers on one side or both sides of a metal sheet, characterized in that: at least two layers of the coating layer are The first coating layer on the lower side is a bubble-containing layer. When the bubble content of the bubble-containing layer is a volume concentration V (%) and the film thickness is t (pm), the following formula is satisfied: -0.1 t+57.5SVS-0.05t+92.5, and 50StS350, the second coating layer on the upper side of the first coating layer contains a coating layer of a melamine-curable polyester resin or an isocyanate-curable polyester resin, and the polyester The number average molecular weight of the resin is 10,000 to 23,000, and the film thickness of the second coating layer is 3 to 30 μm. 2. The precoated metal sheet according to claim 1, wherein the total film thickness of the first coating layer and the second coating layer is Τ (μηι), and is relative to the coating film When the diameter of the bubble measured in the vertical direction is ΙΙν (μηι), there are 20 or more bubbles satisfying Rvg 0.8T in the width of 10 mm of the cross section of any coating film. 3. The precoated metal sheet according to claim 1 or 2, wherein the first coating layer and the second coating layer each contain a pigment of the same color. 4. The precoated metal sheet according to any one of the items 1 to 3, wherein the temperature of the surface opposite to the surface of the metal sheet having the bubble containing layer is set at 80 ° C or more. When the predetermined temperature is lower than °C, the total infrared ray emission rate in the region of the measured wave number 600 to 3OOOcn^1 is 0.50 or less. 5. An electronic device, wherein at least a portion of the outer panel is a precoated metal sheet as claimed in any one of claims 1 to 4 of claim S 39 201111166, and the surface of the bubble containing layer is located outside said The outer side of the board. . 40