Coated body

Abstract

To provide a coated body that enables prevention of snow accretion over a long period of time even in outdoor buildings etc., and combines uniform heat generation for large-area applications, stable conductivity, and high corrosion resistance.SOLUTION: A coated body comprises a substrate, and at least a heat-generating layer and a surface protective layer on a surface of the substrate, and generates heat by energization. The heat-generating layer includes conductive particles composed of a noble metal and / or conductive particles composed of an alloy using a noble metal, and / or conductive particles having a noble metal on their surfaces and / or conductive particles having an alloy using a noble metal on their surfaces, the conductive particles having a density in a range of 1.7 to 10.5 g / cm3. The heat-generating layer has a thickness of 5 to 100 μm and a volume resistivity of 0.1 to 100 mΩ cm.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a coated body having a heat generating layer on the surface of a base material.

Background Art

[0002] Conventionally, for the purpose of preventing snow accumulation and freezing on the roofs of buildings and the like, a method of providing heating wires on the roofs and the like and preventing snow accumulation and freezing by supplying power to the heating wires or generating heat has been known. However, such a method using heating wires has difficulties such as being difficult to directly apply heat to snow and ice and increasing power consumption.

[0003] On the other hand, a method of applying a heat-generating snow-melting paint to the surface of a roof or the like has been proposed. For example, Patent Document 1 proposes a technique of applying a snow-melting paint containing a resin, nickel powder, and at least one of an amino acid or cellulose to a roof or the like as an object. Further, Patent Document 2 proposes a snow-melting coating structure in which a heat-generating coating film layer is formed by applying a snow-melting paint similar to that of Patent Document 1 to a cement-based roofing such as a cement-based inorganic material, and a coating layer is provided on the surface thereof by applying an inorganic paint or a heat-insulating paint.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, in recent years, a technique of applying such a snow-melting paint and generating heat by energization is expected not only for roofs but also for buildings and the like as a technique for preventing snow accumulation. According to the study by the inventors of the present application, in order to generate uniform heat over a large area, it has been found that conductive particles with a low resistivity and a small specific gravity are required, and high corrosion resistance is also required. Here, the resistivity required in the study is a relatively low resistivity (for example, preferably 10 mΩ·cm or less) compared to the conventional one, and at the same time, it is expected that it would be preferable to have a relatively long-term high corrosion resistance of 10 years or more even in the outdoor environment.

[0006] Therefore, as a result of intensive studies by the inventors of the present application along such an object, a coating body having a heat-generating layer containing predetermined conductive particles and a surface protection layer on the surface of a base material and having an adjusted volume resistivity has been found to have uniform heat-generating properties applicable to large-area applications, stable conductivity, high corrosion resistance, etc., and to be able to satisfy the above object, and thus the present invention has been completed.

[0007] Accordingly, an object of the present invention is to provide a coating body having uniform heat-generating properties, stable conductivity, high corrosion resistance, etc. for large-area applications even in outdoor buildings and the like.

[0008] Conventionally, a mechanism that generates heat by power supply has been used as a heating belt of a fixing device in an image forming apparatus such as a digital multi-function peripheral (for example, Patent Document 3). Further, as materials for electronic components, electronic circuits, etc., a coating material adjusted to a predetermined conductivity (resistivity) by containing a conductive filler has been used (for example, Patent Document 4). Further, metal-coated particles in which core particles are coated with a metal layer made of a noble metal such as gold or silver or an alloy thereof, and having a relatively small surface roughness of the metal layer have been shown (for example, Patent Document 5). However, these technologies are only used for the taught applications and purposes, and it has not been taught to be used for snow prevention or snow melting applications in outdoor buildings, etc., nor have they been optimized for such applications and purposes.

Means for Solving the Problems

[0009] That is, the gist of the present invention is as follows. (1) A coated body comprising a base material, and at least a heat generating layer and a surface protection layer on the surface of the base material, which generates heat by energization, The heat generating layer is composed of conductive particles made of a noble metal and / or conductive particles made of an alloy using a noble metal, and / or a noble metal and / or an alloy using a noble metal, and having a density in the range of 1.7 to 10.5 g / cm 3 A coated body characterized by containing conductive particles within the range, having a thickness of 5 to 100 μm, and a volume resistivity of 0.1 to 100 mΩ·cm. (2) The coated body according to (1), characterized in that the noble metal is silver. (3) The coated body according to (1) or (2), characterized in that the conductive particles are silver particles mainly composed of silver or silver-coated particles in which core particles are coated with silver. (4) The coated body according to (1) or (2), characterized in that the content of the conductive particles in the heat generating layer is 25 to 70% by volume. (5) The coated body according to (1) or (2), characterized in that the heat generating layer contains a cured product of an epoxy resin. (6) The coated body according to (1) or (2), wherein the surface protective layer contains a fluororesin and / or a urethane resin. (7) The coated body according to (1) or (2), wherein the base material is a metal having an undercoat film layer on its surface, and a heat generating layer is provided on the surface of the undercoat film layer. (8) The coated body according to (1) or (2), wherein the heat generating layer contains an ion exchanger. (9) The coated body according to (7), wherein the undercoat film layer contains an ion exchanger. (10) The coated body according to (1) or (2), wherein the surface protective layer contains an ion exchanger. [Advantages of the Invention]

[0010] The coated body according to the present invention has uniform heat generation by energization, stable conductivity, high corrosion resistance, etc., and is excellent in the effect of preventing snow accumulation over a long period, for example, in outdoor buildings. [Brief Description of the Drawings]

[0011]

Figure 1

[0012] Hereinafter, the present invention will be described in detail, but the scope of the present invention is not limited to these descriptions, and other than the following examples, it can be appropriately modified and implemented without departing from the gist of the present invention.

[0013] [Base Material] In the present invention, the base material is not limited and can be appropriately selected according to the application. For example, a base material used as a constituent material of a building installed outdoors such as a roof or a rooftop can be mentioned. It is preferably used for metal base materials, glass base materials, hollow base materials, inorganic building materials such as cement and gypsum, and inorganic base materials such as ceramics. Further, these inorganic base materials may be those subjected to any known pretreatment for removing rust generated on the surface, attached oils, dust, dirt such as garbage and tar, and old coating films. In addition, materials such as reinforced fiber plastics, polyvinyl chloride, and organic-inorganic hybrids can also be used. For example, in the case of a constituent material of a building, it is not limited to new installation, and it may be a constituent material of existing equipment in the case of renovation, or a base material in a state where an old coating film remains on a metal or the like. The shape of the base material can be appropriately set according to the application, and there is no limitation on the thickness of the base material, but preferably, a base material having a thickness of about 0.1 mm to 100 mm is used.

[0014] [Heat generating layer] The present invention provides a heat generating layer on the surface of the base material. The heat generating layer has the function of generating heat by energization and is suitable for applications such as preventing snow accumulation and melting snow.

[0015] The heat generating layer may be composed of one or a plurality of layers. Further, the heat generating layer may be provided directly on the surface of the base material, or may be provided with, for example, one or a plurality of undercoat coating film layers (undercoat coating film layer) on the surface of the base material. When the base material is made of a conductive material, it is preferable to provide an undercoat coating film layer as an insulating layer in order to ensure sufficient insulation between the base material and the heat generating layer. The undercoat coating film layer is not limited and may be formed from known undercoat paints and coating means. However, from the viewpoints of adhesion to the base material and the heat generating layer, insulation properties, and corrosion resistance, it is preferable to provide an undercoat coating film layer using an epoxy resin-based, modified epoxy resin-based, vinyl ester resin-based, polyurethane resin-based, or alkyd resin-based undercoat paint. For the purpose of further enhancing the adhesion between the base material serving as a base (including those having an old coating film) and the heat generating layer, a form in which the heat generating layer is directly provided on the surface of the undercoat coating film layer is more preferable. The thickness of the undercoat coating film layer is not limited, but is usually preferably 10 to 200 μm.

[0016] The heat generating layer is composed of at least a coating composition containing conductive particles and a resin.

[0017] <Conductive particles> The conductive particles used in the present invention are conductive particles made of a noble metal and / or conductive particles made of an alloy using a noble metal and / or conductive particles having a noble metal on the surface and / or conductive particles having an alloy using a noble metal on the surface. That is, any one or two or more of conductive particles made of a noble metal, conductive particles made of an alloy using a noble metal, conductive particles having a noble metal on the surface, and conductive particles having an alloy using a noble metal on the surface may be used, and two or more of each may be used, or a mixture thereof may also be used. Using a noble metal is preferable because it can prevent corrosion and discoloration even when used outdoors. The noble metal is not limited, but is selected from gold, silver, platinum, palladium, rhodium, iridium, ruthenium, osmium, etc. Among these, it is more preferable to use silver in terms of availability, cost, conductivity, and color.

[0018] The conductive particles made of a noble metal do not exclude extremely trace unavoidable components other than the noble metal, and it is sufficient that the noble metal is the main component. Also, an alloy using the noble metal as described above may be used. The alloy using the noble metal is not limited either, but may be an alloy of the above noble metals, or an alloy containing the above noble metal and at least one metal selected from other metals (for example, iron, nickel, chromium, cobalt, titanium, copper, vanadium, and manganese, etc.). The content of the noble metal as the main component in the alloy is preferably 25% by mass or more, more preferably 30% by mass or more. Also, the purity when consisting only of a noble metal is preferably 98% or more, more preferably 99% or more, and most preferably close to 100%. That is, as the conductive particles made of a noble metal, silver particles having silver as the main component are more preferable. Such conductive particles made of a noble metal or conductive particles made of an alloy using a noble metal are not particularly limited, but can be manufactured using a known manufacturing method. Also, it is possible to use commercially available products.

[0019] On the other hand, the conductive particles having a noble metal on the surface are noble metal-coated particles in which the noble metal is coated on the surface of core particles made of a material other than the noble metal, such as by plating. For the noble metal to be coated, it is preferable to adopt the same embodiment as described above. Similarly, as conductive particles having an alloy using a noble metal on the surface, the surface of core particles made of a material other than the noble metal or the alloy using the noble metal is coated with an alloy containing a noble metal coated by plating or the like. For the alloy using the noble metal to be coated, it is preferable to adopt the same embodiment as described above. Here, the material constituting the core particles is not limited. As long as the material is difficult to corrode or oxidize, metals other than noble metals such as nickel and copper can be used, but it is preferably a non-metal in order to prevent corrosion. For example, it is more preferable to use silica, acrylic resin, glass beads, graphite, mica, or the like. Among these, it is even more preferable to use silica or acrylic as the core particles because of easy availability, low cost, good dispersibility, and easy selection of shape. By adopting such a core material, the amount of noble metal used can be reduced, and problems such as migration can be suppressed. Such conductive particles having a noble metal on the surface or conductive particles having an alloy using a noble metal on the surface are not particularly limited, but can be manufactured using known manufacturing methods. It is also possible to use commercially available products.

[0020] And, it is preferable that the conductive particles are uniformly blended in the heat-generating layer from the viewpoint of exerting the functions of conductivity and resistivity as a coating body. That is, it is preferably uniformly dispersed in the paint composition used when forming the heat-generating layer. For such a purpose, the density of the conductive particles is 1.7 to 10.5 g / cm 3 It is necessary to be. When the density is 10.5 g / cm 3If it exceeds this range, it is likely to sediment and accumulate in the paint composition when forming the heat - generating layer, and the uniform arrangement may be impaired when the heat - generating layer is formed. As a result, stable conductivity may not be obtained, which may lead to a decrease in the cohesive force of the coating film of the heat - generating layer, and there is a risk that the heat - generating layer is likely to peel off. On the other hand, when the density is less than 1.7 g / cm 3 In the case of less than this value, the coating with the noble metal becomes non - uniform. In this case as well, the conductivity becomes unstable, which is not preferable. The density of the conductive particles is preferably 2.9 - 9.5 g / cm 3 .

[0021] The shape of the conductive particles is not limited, and particles with known shapes and forms can be used. The average particle diameter of the conductive particles is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 15 μm or less. The average particle diameter is defined as the average particle diameter (median diameter: D50) derived from the volume distribution measured by the laser diffraction scattering method. When the average particle diameter is within the above range, the dispersibility and coatability to the heat - generating layer (paint composition) are excellent, and a uniform coating film is likely to be formed. Thereby, it is considered to contribute to realizing the desired conductivity and resistivity.

[0022] Also, although the compounding amount of the conductive particles is not limited, from the balance between conductivity and heat - generating property, it is preferably compounded so as to be 30 - 60 volume (vol)% in the solid content of the heat - generating layer. More preferably, it is compounded so as to be 35 - 55 vol%. Also, the content of the conductive particles can be exemplified as being 25 - 90 mass% in the solid content of the heat - generating layer, and preferably 45 - 85 mass%.

[0023] <Resin (cured resin)> As the resin (cured resin) used for the heat - generating layer, in addition to the miscibility and stability with the above - mentioned conductive particles, etc., it can be appropriately selected from known resins in consideration of corrosion resistance, adhesion, workability, and use conditions, etc. It can be selected from resins commonly used in the paint industry, and it may be a resin used in a one - component paint composition, or a resin used in a two - component paint composition used in combination with a curing agent described later. Specifically, examples include acrylic resin, silicone resin, acrylic silicone resin, styrene acrylic copolymer resin, polyester resin, fluororesin, rosin resin, petroleum resin, coumarone resin, phenol resin, urethane resin, melamine resin, urea resin, epoxy resin, cellulose resin, xylene resin, alkyd resin, aliphatic hydrocarbon resin, butyral resin, maleic acid resin, fumaric acid resin, vinyl resin, amine resin, ketimine resin, polysiloxane resin, polysilazane, etc. Among these, from the viewpoints of excellent adhesion to the substrate, volume stability, thermal stability, etc., epoxy resin, acrylic resin, polyurethane resin, and acrylic silicone resin are preferable, more preferably epoxy resin or acrylic resin, and even more preferably epoxy resin. The resin may be used alone or in combination of two or more kinds.

[0024] The epoxy resin preferably has at least two epoxy groups in one molecule, and is, for example, obtained by reacting a polyhydric alcohol or polyhydric phenol with a halohydrin. Specific examples include bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, novolac type epoxy resin, polyglycol type epoxy resin, bisphenol F type epoxy resin, epoxidized oil, 1,6 - hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether. It may also be an epoxy ester resin having an ester moiety obtained by reacting the carboxyl group of a carboxylic acid such as acrylic acid or methacrylic acid with the epoxy group of these epoxy resins. The epoxy equivalent of the epoxy resin is not particularly limited, but from the viewpoint of adhesion to the substrate, etc., it is preferably 100 - 1000 g / eq. on average.

[0025] As the epoxy resin, a modified epoxy resin obtained by modifying the epoxy resin may be used. The method of modification of the modified epoxy resin is not limited. For example, it may be one obtained by modifying the above epoxy resin by a method using a known modifier. For example, depending on the modifier, amine modification, isocyanate modification, acrylic modification, polyester modification, urethane modification, fatty acid modification, phenol modification, alkylphenol modification, phenol novolak modification, alkylphenol novolak modification, etc. may be mentioned. For a phenol-modified epoxy resin, an alkylphenol-modified epoxy resin, a phenol novolak-modified epoxy resin or an alkylphenol novolak-modified epoxy resin, for example, at least one epoxy resin selected from glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, and aromatic epoxy resins is modified with a phenol resin, an alkylphenol resin, a phenol novolak resin or an alkylphenol novolak resin, or a phenol resin, an alkylphenol resin, a phenol novolak resin or an alkylphenol novolak resin and epichlorohydrin are reacted. It can be obtained by the method.

[0026] When using a modified epoxy resin, from the viewpoint of reactivity with a curing agent described later, it is preferably modified so that a predetermined amount of epoxy groups remain to satisfy the above epoxy equivalent. The amount of modification can be appropriately adjusted within a range that does not impair the object of the present invention, including the above weight average molecular weight, epoxy equivalent, type of modification, and the like.

[0027] The acrylic resin is a polymer of acrylic acid esters or methacrylic acid esters. For example, polymers obtained by polymerizing one or more acrylic components selected from acrylic acid, methacrylic acid and their esters, amides and nitriles, etc. may be mentioned. Furthermore, polymers obtained by polymerizing an acrylic component and a non-acrylic component such as styrene are also included.

[0028] In the heat - generating layer, the content of the resin is preferably formulated to be 40 - 70 vol% in the solid content. More preferably, it is formulated to be 45 - 65 vol%. Also, the content of the resin can be exemplified as being 10 - 60 mass% in the solid content of the heat - generating layer, and preferably 15 - 50 mass%.

[0029] When used in a two - component paint composition used in combination with a curing agent, the curing agent can be appropriately selected according to the type of resin used, and a curing agent commonly used in the paint industry can be used. These curing agents may be used alone or in combination of two or more. The content of the curing agent is appropriately adjusted according to the amount of reactive groups with the curing agent contained in the resin. However, in the paint composition for forming the heat - generating layer, the content of the curing agent in the solid content is preferably, for example, 1.0 - 30 wt%.

[0030] For epoxy resins, amine - based curing agents can be preferably used. Specific examples include aliphatic polyamines containing alicyclics such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, triaminopropane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, and 1,3 - bis(aminomethyl)cyclohexane; aromatic polyamines such as phenylenediamine, metaxylylenediamine, paraxylylenediamine, and diaminodiphenylmethane; other polyamine compounds such as polyoxyethylenediamine, polyoxypropylenediamine, triethylene glycol diamine, and tripropylene glycol diamine, and modified polyamine compounds obtained by modifying the amino groups of these amine compounds. Here, known methods can be used for the modification of the above - mentioned amine compounds. Examples of the modification reaction include amidation of amino groups, Mannich reaction of amino groups and carbonyl compounds, and addition reaction of amino groups and epoxy groups. Here, a modified polyamine compound of the type in which an epoxy group or the like is added to an amino group is called an adduct - type modified polyamine compound, and an epoxy - adduct - type modified polyamine compound in which an epoxy group is added to an amino group is preferred.

[0031] Also, for example, with respect to a resin containing a hydroxyl group (such as a hydroxyl group-containing acrylic resin), an isocyanate-based curing agent can be preferably used. Specific examples include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methylcyclohexane diisocyanate, bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, dimer acid diisocyanate, lysine diisocyanate, etc. In addition, modified products of these polyisocyanates can be mentioned. Specific examples of the modified products include biuret-modified products, isocyanurate-modified products, adduct-modified products (for example, trimethylolpropane adducts), allophanate-modified products, uretdione-modified products, etc.

[0032] As described above, from the viewpoint of excellent corrosion resistance, adhesion to the base material, etc., the resin (resin cured product) forming the heat-generating layer of the present invention is preferably an epoxy resin as the resin, and it is preferably used in a two-component paint composition with the amine compound as the curing agent. Regarding the amount of the amine compound used, the equivalent ratio (active hydrogen equivalent / epoxy equivalent) of the functional group (active hydrogen) contained in or generated from the amine compound to 1 equivalent of the epoxy group in the epoxy resin is preferably 0.5 to 1.5, more preferably 0.6 to 1.3, and even more preferably 0.7 to 1.2 from the viewpoints of coating film drying property and curability. As the curing agent for the acrylic resin, it is preferably used in a two-component paint composition with the isocyanate-based compound. Regarding the amount of the isocyanate compound used, the equivalent ratio (active hydrogen equivalent / hydroxyl group equivalent) of the functional group (active hydrogen) contained in or generated from the isocyanate compound to 1 equivalent of the hydroxyl group in the acrylic resin is preferably 0.5 to 1.5, more preferably 0.7 to 1.3, and even more preferably 0.8 to 1.2 from the viewpoints of coating film drying property and curability.

[0033] <Other components> When forming the heat-generating layer, other components other than the above-mentioned conductive particles and resin (cured resin) may be blended as long as the object of the present invention is not impaired. Any other components may be used in the paint field. For example, it can include all ordinary paint additives such as rust preventive pigments, extender pigments, coloring pigments, pigment dispersants, surface modifiers, anti-sagging agents (anti-settling agents), silane coupling agents, defoaming agents, driers, anti-skinning agents, etc. These other components are preferably about 0 to 20% by mass in the paint composition for forming the heat-generating layer, and can be appropriately selected and blended according to the purpose.

[0034] When forming the heat-generating layer, a substance having ion-exchange ability (referred to as an ion exchanger) may be added. When the purpose is snow prevention or snow melting in outdoor buildings, etc., the heat-generating layer may be exposed to high-temperature and high-humidity environments, and various corrosion factors may penetrate into the heat-generating layer from the external environment or the coating film or substrate in contact with the heat-generating layer. Therefore, the noble metal on the surface of the conductive particles may be ionized or re-precipitated, significantly impairing the conductivity. Corrosion factors include chloride ions, sulfate ions, ammonium ions, etc. By adding a substance that ion-exchanges anions, cations, or both ions to the heat-generating layer, ionization and re-precipitation of the noble metal on the surface of the conductive particles can be prevented. Regarding the content of the ion exchanger, it is preferably about 0 to 30% by mass in the paint composition for forming the heat-generating layer, more preferably 2 to 25% by mass, and even more preferably 5 to 25% by mass, and can be appropriately selected and blended according to the purpose.

[0035] Here, the ion exchanger can be a cation exchanger, an anion exchanger, or a both-ion exchanger depending on the ion to be exchanged, and can also be an organic ion exchanger or an inorganic ion exchanger depending on the components constituting it. These can be appropriately selected or used in combination. Examples of the organic ion exchanger include compounds having a polymer acid to which an acidic group such as an acidic hydroxyl group, a carboxyl group, or a sulfonic group is bonded. Examples of the inorganic ion exchanger include metal compounds, such as metal hydrous oxides. Specifically, hydrous oxides of Si, Ti, Nb, Sn, Zr, Mg, Al, Sb, Fe, etc., phosphates with tetravalent metals such as Zr, Sn, Ti, and synthetic zeolites can be mentioned. Among these, in the present invention, from the viewpoints of heat resistance and stability, etc., it is preferable to use an inorganic ion exchanger.

[0036] Examples of the inorganic ion exchanger include, for example, "IXE-100" etc. (Toagosei Co., Ltd.) as a cation exchanger. Examples of the anion exchanger include, for example, "IXE-500", "IXE-530", "IXE-550", "IXE-700F", "IXE-770D", "IXE-800" (Toagosei Co., Ltd. above). Further, examples of the both-ion exchanger include, for example, "IXE-600", "IXE-633", "IXE-6107", "IXE-6136", "IXEPLUS-A1", "IXEPLUS-A2", "IXEPLUS-B1" (Toagosei Co., Ltd. above). These inorganic ion exchangers may be used alone or in combination of two or more.

[0037] <Method for forming the heat generating layer> As a method for forming the heat-generating layer, the above-described conductive particles, resin, and other optional components are mixed to prepare a paint composition, and the paint composition is applied to the surface of a substrate or a substrate with an undercoat film and then dried. As a mixing method, particularly in the case of a two-component paint composition using a main agent and a curing agent as resin components, the conductive particles may be blended at the timing of mixing the main agent and the curing agent, or the procedure of mixing the main agent and the curing agent may be adopted in a state where the conductive particles are previously blended with either the main agent or the curing agent.

[0038] As a mixing method of the paint composition, it can be appropriately selected from all mixing means used in the paint field. For example, it can include dispersing stirring, homogenizer, ball mill, sand mill, dyno mill, kneader coater, roll mill, etc. Among these, from the viewpoint of uniformly dispersing the conductive material without crushing it, it is preferable to mix using dispersing stirring.

[0039] Regarding the method of applying the prepared paint composition to a substrate or the like, it can also be appropriately selected from all coating means used in the paint field. For example, it can include brush coating, roller coating, spatula coating, trowel coating, flow coater coating, spray coating (e.g., air spray coating, airless spray coating, etc.). The coating amount is about 0.03 to 0.2 kg / m in terms of solid content, and it is naturally dried or heat-dried. At this time, the viscosity of the paint composition during coating is preferably adjusted within the range of 0.5 to 100 (Pa·s, 23°C) at a shear rate of 0.1 s. 2 Regarding the method of applying the prepared paint composition to a substrate or the like, it can also be appropriately selected from all coating means used in the paint field. For example, it can include brush coating, roller coating, spatula coating, trowel coating, flow coater coating, spray coating (e.g., air spray coating, airless spray coating, etc.). The coating amount is about 0.03 to 0.2 kg / m in terms of solid content, and it is naturally dried or heat-dried. At this time, the viscosity of the paint composition during coating is preferably adjusted within the range of 0.5 to 100 (Pa·s, 23°C) at a shear rate of 0.1 s. -1 For the viewpoint of uniform coating and uniform heat generation, it is preferable that the viscosity at a shear rate of 0.1 s is adjusted within the range of 0.5 to 100 (Pa·s, 23°C).

[0040] <Properties of the heat-generating layer> The heat - generating layer formed as described above should have a thickness of 5 to 100 μm. When the thickness of the heat - generating layer is less than 5 μm, there is a concern that the influence on the resistance value due to coating film defects such as film thickness differences caused by the unevenness of the base may increase, and the heat generation may become non - uniform. On the other hand, when the thickness of the heat - generating layer exceeds 100 μm, there is a risk of causing coating film peeling due to an increase in coating film stress. In particular, since the heat - generating layer of the present invention is used in a form that repeatedly raises and lowers the temperature, it is preferable that the expansion and contraction due to heat are small. By setting the upper limit value as described above, it is possible to suppress the increase in coating film stress and coating film peeling, which is preferable. The thickness of the heat - generating layer is preferably 10 to 80 μm, more preferably 20 to 70 μm.

[0041] Also, the heat - generating layer formed as described above should have a volume resistivity of 0.1 to 100 mΩ·cm. It has been found that the required resistivity within the study needs to be a relatively low resistivity compared to the conventional ones. Preferably, the upper limit value of the resistivity is preferably 60 mΩ·cm or less, more preferably 10 mΩ·cm or less. Even more preferably, the volume resistivity of the heat - generating layer is 0.1 to 10 mΩ·cm.

[0042] <Power - supply means> The means for energizing the heat - generating layer is not limited. For example, by providing a terminal, electrode, conductive plate, conductive tape, power - supply wire, etc. on a part of the heat - generating layer and connecting an external power source equipped with known devices and members such as a controller capable of adjusting power thereto, the heat - generating layer can be energized. The voltage and current during energization can be appropriately adjusted so as to obtain the desired heat generation.

[0043] [Surface protection layer] In the coated body of the present invention, after forming the above - mentioned heat - generating layer, one or more surface protection layers are formed on its surface. By providing the surface protection layer, the corrosion resistance, weather resistance, and insulation can be made more reliable. As the surface protective layer, its type, thickness, etc. are not limited as long as the corrosion resistance and the like can be improved. Usually, it may be formed as a topcoat film or a thick-film topcoat film in the paint field, or it may be formed as a multi-layer coating film layer such as an intermediate coat film and a topcoat film. However, it is preferable to have two or more layers as the intermediate coat film and the topcoat film. As the surface protective layer, one or more paints that can be usually used can be appropriately selected and applied. For example, a paint containing at least one selected from the group consisting of acrylic resin-based paints, urethane resin-based paints, epoxy resin-based paints, chlorinated polyolefin-based paints, silicone resin-based paints, and fluororesin-based paints is preferably used to form a coating film in 1 to 4 layers. Among these, from the viewpoint of life cycle cost, it is preferably formed from a paint containing a fluororesin and / or a urethane resin, and more preferably a fluororesin-based paint containing a fluororesin is used.

[0044] When forming the undercoat film layer of the surface protective layer or the heat-generating layer, the aforementioned ion exchanger may be added. When the purpose is snow prevention or snow melting for outdoor buildings, etc., the heat-generating layer may be exposed to a high-temperature and high-humidity environment, and various corrosion factors may penetrate into the heat-generating layer from the external environment, the coating film in contact with the heat-generating layer, or the base material. Therefore, the noble metal on the surface of the conductive particles may be ionized or redeposited, significantly impairing the conductivity. Corrosion factors include chloride ions, sulfate ions, ammonium ions, etc. By adding a substance that ion-exchanges anions, cations, or both ions to the undercoat film layer of the surface protective layer or the heat-generating layer, ionization and redeposition of the noble metal on the surface of the conductive particles can be prevented. The ion exchanger is preferably about 0 to 30% by mass, more preferably 0.5 to 20% by mass, and still more preferably 1 to 15% by mass in the paint composition for forming the undercoat film layer of the surface protective layer or the heat-generating layer, and can be appropriately selected and blended according to the purpose.

[0045] The water vapor transmission rate of the surface protective layer formed by the topcoat and intermediate coat paints is 50 g / (m 2·day) is preferably as follows. Further, 25 g / (m 2 ·day) is more preferably, and even more preferably 10 g / (m 2 ·day) or less is preferable from the viewpoint of protecting the heating layer. By using a two-component epoxy resin with an amine-based compound as a curing agent as the intermediate coating paint, it is presumed that the reducibility of the amine compound contributes to improving the corrosion resistance.

[0046] In addition, in order to ensure sufficient insulation from the heating layer, the surface protection layer preferably has a volume resistivity of 10 6 Ω·cm or more as measured by an electrical insulation test, and more preferably 10 10 Ω·cm or more. The electrical insulation test can be performed by the method described in the examples.

[0047] The thickness of the surface protection layer is not limited, but the total thickness of the surface protection layer is preferably 55 μm or more. The upper limit is not limited either, but it is preferably 100 μm or less. The drying method of the paint may be air drying at room temperature. As the physical properties of the dried paint film, weather resistance, water resistance, adhesion, alkali resistance, flex resistance, acid resistance, etc. are required. If it is an intermediate coating paint, it is preferably a paint that satisfies the regulations of JIS K5659 (Intermediate Coating for Weather-Resistant Paint for Steel Structures), and if it is a top coating paint, it is preferably a paint that satisfies the regulations of JIS K5659 (Top Coating for Weather-Resistant Paint for Steel Structures).

Examples

[0048] Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to these examples and comparative examples. In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified.

[0049] 1. Preparation of paint composition First, according to the formulation shown in Tables 1 to 2, the main component and the curing agent component were prepared. The units of the numerical values in Tables 1 to 2 are "mass%". The components shown in Tables 1 to 2, the conductive particles used, and the ion exchanger will be described below. In the present application, the conductive particles and the ion exchanger are collectively referred to as "pigment components". *1 Manufactured by Dow Chemical Japan Co., Ltd., trade name "D.E.R. TM 671-X70", non-volatile content 70% by mass, epoxy equivalent (non-volatile content converted value) 445 to 500 g / eq. *2 Manufactured by DIC Corporation, trade name "EPICLON 830", non-volatile content 100% by mass, epoxy equivalent 175 g / eq. *3 Manufactured by DIC Corporation, trade name "EPICLON 5920-70MS", non-volatile content 70% by mass, epoxy equivalent 930 g / eq. *4 Manufactured by DIC Corporation, trade name "Acrylic Acid A-827", non-volatile content 65% by mass. *5 Manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name "SR-16H", non-volatile content 100%. *6 Manufactured by ExxonMobil, trade name "Solvesso 100" *7 Manufactured by DIC Corporation, trade name "Lacquamide TD-961DN", non-volatile content 50% by mass. *8 Manufactured by T&K TOKA Co., Ltd., trade name "Fujicure FXD-822", non-volatile content 100% by mass. *9 Manufactured by Taido Sangyo Co., Ltd., trade name "Daitoclear X-6132", non-volatile content 100% by mass. *10 Manufactured by Fuji Kasei Kogyo Co., Ltd., trade name "Fujicure FXP-8086", non-volatile content 100% by mass. *11 Manufactured by Asahi Kasei Corporation, trade name "Duranate TPA-100", non-volatile content 100% by mass *12 Manufactured by Asahi Kasei Corporation, trade name "Duranate TKA-100", non-volatile content 100% by mass <Conductive Particles> *13 Silver powder manufactured by Company a, average particle diameter (D50) 2.5 μm, true density 10.5 g / cm 3 *14 Silver-coated silica particles manufactured by Company b, average particle diameter (D50) 3.0 μm, true density 2.9 g / cm 3 *15 Carbon-coated copper particles manufactured by Company C, average particle diameter (D50) 5.0 μm, true density 9.1 g / cm 3 *16 Silver-coated nickel particles manufactured by Company D, average particle diameter (D50) 12.0 μm, true density 9.1 g / cm 3 *17 Carbon black particles manufactured by Company E, average particle diameter (D50) 3.0 μm, true density 2.2 g / cm 3 *18 Nickel powder manufactured by Company F, average particle diameter (D50) 4.0 μm, true density 7.8 g / cm 3 *19 Stainless steel (SUS316L) powder manufactured by Company G, average particle diameter (D50) 3.1 μm, true density 7.9 g / cm 3 <Ion exchanger> *20 Amphoteric ion exchanger manufactured by Toagosei Co., Ltd., trade name "IXE-600", average particle diameter (D50) 1.0 μm, true density 5.5 g / cm 3 *21 Cation exchanger manufactured by Toagosei Co., Ltd., trade name "IXE-100", average particle diameter (D50) 1.0 μm, true density 3.0 g / cm 3

[0050]

Table 1

[0051]

Table 2

[0052] [Example 1] Next, the main agent prepared in Table 1 above, the curing agent prepared in Table 2 above, and the conductive particles were mixed in a dispersion stirrer until uniform according to the formulation shown in Table 3 below to prepare a paint composition for the heating layer. In Table 3, the unit of the composition of the paint composition is "mass%" except for the parts indicated by volume (vol)%. The same applies to Tables 4 to 8 hereafter. Also, in Tables 3 to 8, NV represents the non-volatile content, and PVC represents the volume concentration of the pigment component.

[0053]

Table 3

[0054]

Table 4

[0055]

Table 5

[0056]

Table 6

[0057]

Table 7

[0058]

Table 8

[0059] 2. Measurement and Evaluation Methods Test Plate Fabrication Method On a grit blast plate (3.2 × 70 × 150 mm), as an undercoat film layer (insulating layer), Epole Smyle (modified epoxy resin paint manufactured by Dainippon Paint Co., Ltd.) was spray-coated to a dry film thickness of 60 μm and dried. The paint composition for the heating layer was brushed on to a dry film thickness of 50 μm and dried at room temperature for 1 week to produce a heating layer. A conductivity test was performed on the produced heating layer. Thereafter, on the surface of the heating layer, a primer paint (product name "V Freon #100H Smyle Primer" manufactured by Dainippon Paint Co., Ltd.) and a topcoat paint (product name "V Freon #100H Smyle Topcoat IG" manufactured by Dainippon Paint Co., Ltd.) were each brushed on at intervals of 30 μm and 25 μm with a 1-day coating interval, and dried at room temperature for 7 days to form a surface protection layer composed of a primer coating film and a topcoat film, and then a coated body (test panel) was obtained. The obtained coated body (test panel) was subjected to an insulation test. Similarly, the back surface of the obtained coated body (test panel) was sealed with the same paint as the paint used for the undercoat film layer, dried at room temperature for 7 days, and then subjected to a corrosion resistance test and a weather resistance test. In addition, a separate isolation film with a primer coating film and a topcoat film overcoated was separately prepared, and when the water vapor transmission rate of the surface protection layer was measured using L80-6000 manufactured by Illinois, it was 4.0 g / (m 2 ·day). Incidentally, when a separate isolation film with only the primer coating film in Example 16 without a topcoat film was prepared in the same manner and the water vapor transmission rate was measured, it was 6.2 g / (m 2 ·day).

[0060] (1) Conductivity The test panel obtained by the above test panel production method was used for the evaluation of the conductivity test in accordance with JIS K7194 (4-probe method). The volume resistivity (ρV) of the heating layer was evaluated as follows. 〇: The volume resistivity of the heating layer is 0.1 ≦ ρV ≦ 10 mΩ·cm. △: The volume resistivity of the heating layer is 10 mΩ·cm < ρV ≦ 100 mΩ·cm. ×: The volume resistivity of the heating layer is ρV < 0.1 mΩ·cm, 100 mΩ·cm < ρV. In Table 5, for example, "E+04" means "×104 It shows "」", and other comparative examples follow this. Also, O.L. indicates over-resistance.

[0061] (2) Corrosion resistance The test plates obtained by the above test plate manufacturing method were exposed to salt water spray for 2000 hours in accordance with the neutral salt spray resistance of JIS K5600-7-1:1999. During this process, the degree of rust, swelling, etc. that occurred on the test plates was evaluated every 200 hours according to the following criteria. 〇: After 2000 hours, there is no abnormality on the coating surface, and the coating appearance is excellent. △: By the time 2000 hours have passed, abnormalities such as rust and swelling are recognized on a part of the coating surface. ×: By the time 400 hours have passed, abnormalities such as rust and swelling are recognized on a part of the coating surface.

[0062] (3) Weather resistance The test plates obtained by the above test plate manufacturing method were subjected to an accelerated weather resistance test for 2000 hours in accordance with the xenon lamp method of JIS K5600-7-7:2008, and the gloss value of the coating film was evaluated according to the following criteria. 〇: The gloss retention rate after the specified time has passed is 80% or more. △: The gloss retention rate after the specified time has passed is 80% or more and less than 60%. ×: The gloss retention rate after the specified time has passed is 60% or less.

[0063] (4) Insulation The test plates obtained by the above test plate manufacturing method were used for the evaluation of the electrical insulation test of the surface protection layer in accordance with JIS K7194 (four-probe method). The electrical insulation was evaluated according to the following criteria. 〇: The volume resistivity of the surface protection layer is 10 10 Ω·cm ≦ ρV. △: The volume resistivity of the surface protection layer is 10 6 Ω·cm ≦ ρV < 10 10 Ω·cm. ×: The volume resistivity of the surface protection layer is ρV < 10 6 Ω·cm.

[0064] (5) Exothermic Method for manufacturing test plate In Example 1, on a galvanized plate (0.03 × 2.5 × 22 cm) with a polished surface, Epole Smyle (modified epoxy resin paint manufactured by Dainippon Paint Co., Ltd.) was brush-coated as an undercoat film layer (insulating layer) so that the dry film thickness was 60 μm. Next, masking was performed so that the central part of the test piece was 1.5 × 20 cm, and a paint composition for the heating layer was brush-coated on the surface of the undercoat film layer so that the dry film thickness was 50 μm. After drying for 24 hours, conductive tapes were attached to a width of 1 cm from both ends of the heating layer, connected to conductive terminals, and connected to a power supply device (see Fig. 1). Thereafter, on the surface of the heating layer, a primer paint (product name: "V Freon #100H Smyle Primer" manufactured by Dainippon Paint Co., Ltd.) and a topcoat paint (product name: "V Freon #100H Smyle Topcoat IG" manufactured by Dainippon Paint Co., Ltd.) were successively brush-coated at coating intervals of one day, 30 μm and 25 μm respectively, and dried at room temperature for 7 days to form a surface protection layer composed of a primer coating film and a topcoat coating film, and a coated body (test plate) was obtained. The test plate obtained by the above test plate manufacturing method was left standing in a -5°C environment, and after the temperature of the test plate became constant, it was energized. The surface temperature of the test plate when 2.0 A was applied was evaluated according to the following criteria. 〇: When the energization (power density) is 125 W / m 2 or more, and the surface temperature is 5°C or more. △: When the energization (power density) is 80 W / m 2 or more and less than 125 W / m 2 and the surface temperature is 3°C or more and less than 5°C. ×: When the energization (power density) is less than 80 W / m 2 and the surface temperature is less than 3°C.

[0065] [Examples 2 to 16, Comparative Examples 1 to 8, Examples 17 to 25] Also, from Example 2 onwards, except that the composition in the paint composition for the heat - generating layer and the dry film thickness were changed according to the descriptions in Tables 3 - 8, the undercoat paint was changed to the product name "Epole HB Smile" (modified epoxy resin paint, denoted as "Epoxy HB Sm" in the table) manufactured by Dainippon Paint Co., Ltd., the intermediate coat paint and the top - coat paint were changed to the product name "V - Top H Smile Topcoat (polyol isocyanate - curing type paint)" manufactured by Dainippon Paint Co., Ltd., and the top - coat film was not provided, the same experiments were conducted. Also, when the V - Top H Smile Topcoat was used for the top - coat film, the water vapor transmission rate of the intermediate - coat film and the top - coat film was 6.3 g / (m 2 ·day).

[0066] (6) High temperature and high humidity resistance [Example 17] Test plate preparation method In Example 17, on an iron plate (0.03×2.5×22 cm) with a polished surface, as the under - coat film layer (insulating layer), Epole HB Smile (modified epoxy resin paint manufactured by Dainippon Paint Co., Ltd., denoted as "Epoxy HB Sm" in the table) was spray - coated to a dry film thickness of 60 μm and dried. The paint composition for the heat - generating layer was brush - coated to a dry film thickness of 50 μm and dried at room temperature for 1 week to produce the heat - generating layer. The test plate obtained by the above test plate preparation method was left standing in an environment of 70°C and 90% relative humidity for 1000 hours. The test plate was energized at room temperature, and the resistance of the heat - generating layer was measured. The resistance ratio of the heat - generating layer before and after the test start was evaluated according to the following criteria. ◎: The resistance of the heat - generating layer at the end of the test is less than 1.0 times the initial test plate resistance. ○: The resistance of the heat - generating layer at the end of the test is 1.0 times or more and less than 1.5 times the initial test plate resistance. △: The resistance of the heat - generating layer at the end of the test is 1.5 times or more the initial test plate resistance.

[0067] [Examples 18 - 22] Also, from Example 18 onwards, except that the composition in the paint composition for the heat - generating layer or the composition of the under - coat paint was changed to incorporate an ion - exchanger, the same experiments were conducted.

[0068] [Example 23] Method for preparing test board In Example 23, on a tinned plate (0.03×2.5×22 cm) with a polished surface, as an undercoat film layer (insulating layer), an undercoat paint containing an ion exchanger in Epo HB Smile (modified epoxy resin paint manufactured by Dainippon Paint Co., Ltd., denoted as "Epo HB Sma" in the table) was spray-coated to a dry film thickness of 60 μm and dried. The paint composition for the heat-generating layer containing the ion exchanger was brush-coated to a dry film thickness of 50 μm and dried at room temperature for 1 week to prepare the heat-generating layer. Then, on the surface of the heat-generating layer, a primer paint (product name "V Freon #100H Smile Primer" manufactured by Dainippon Paint Co., Ltd.) and a topcoat paint (product name "V Freon #100H Smile Topcoat IG" manufactured by Dainippon Paint Co., Ltd.) were each brush-coated at 30 μm and 25 μm intervals with a 1-day coating interval, and dried at room temperature for 7 days to form a surface protection layer, and then a coated body (test board) was obtained. The test board obtained by the above test board preparation method was left standing in an environment of 70°C and 90% relative humidity for 1000 hours. The test board was energized at room temperature, and the resistance of the heat-generating layer was measured. The resistance ratio of the heat-generating layer before and after the start of the test was evaluated according to the following criteria. ◎: The resistance of the heat-generating layer at the end of the test is less than 1.0 times the initial resistance of the test board. ○: The resistance of the heat-generating layer at the end of the test is 1.0 times or more and less than 1.5 times the initial resistance of the test board. △: The resistance of the heat-generating layer at the end of the test is 1.5 times or more the initial resistance of the test board.

[0069] [Examples 24 - 25] Also, in Examples 24 and 25, the same experiments were conducted except that the composition was changed so as to incorporate an ion exchanger in the composition of the undercoat paint and / or the composition of the primer paint, respectively.

Claims

1. A coated body comprising a base material and at least a heat - generating layer and a surface protection layer on the surface of the base material, which generates heat when an electric current is passed through, The heat-generating layer is composed of conductive particles made of a noble metal and / or conductive particles made of an alloy using a noble metal and / or conductive particles having a noble metal on the surface and / or conductive particles having an alloy using a noble metal on the surface, and the density is within the range of 1.7 to 10.5 g / cm ３ The coated body is characterized by including conductive particles within the range, having a thickness of 5 to 100 μm, and having a volume resistivity of 0.1 to 100 mΩ·cm.

2. The coated body according to claim 1, wherein the noble metal is silver.

3. The coated body according to claim 1 or 2, wherein the conductive particles are silver particles mainly composed of silver or silver - coated particles in which core particles are coated with silver.

4. The coated body according to claim 1 or 2, wherein the content of the conductive particles in the heat - generating layer is 25 to 70% by volume.

5. The coated body according to claim 1 or 2, wherein the heat - generating layer contains a cured product of an epoxy resin.

6. The coated body according to claim 1 or 2, wherein the surface protection layer contains a fluororesin and / or a urethane resin.

7. The coated body according to claim 1 or 2, wherein the base material is a metal having an under - coat film layer on its surface, and the heat - generating layer is provided on the surface of the under - coat film layer.

8. The coated body according to claim 1 or 2, wherein the heat - generating layer contains an ion - exchanger.

9. The coated body according to claim 7, wherein the under - coat film layer contains an ion - exchanger.

10. The coated body according to claim 1 or 2, wherein the surface protection layer contains an ion - exchanger.

Images