KR20060106666A - High thermal emissive coated metal material - Google Patents

Abstract

In a metal coating body in which at least one layer of resin coating film is formed on one side or both sides of a metal base, the outermost layer is formed by exposing at least part of porous particles having pores of 1 to 1000 nm that are open to the surface from the surface of the outermost layer. The coating metal material excellent in the heat dissipation which is contained in the state and in which the coating film layer containing the radioactive additive was formed in the lower layer side is disclosed. This coated metal material is excellent in heat dissipation and is useful as a material of a casing which accommodates electronic devices (including electric devices and optical devices incorporating heat sources. The same applies hereinafter).

Description

High thermal emissive coated metal material

1 is an explanatory diagram showing a principle of calculating the radiant heat amount Q2 and the convective heat amount Q1 of a coated metal plate.

(Technology)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated metal material having excellent heat dissipation, and is particularly useful as a material of a casing that accommodates an electronic device (including an electric device or an optical device with a built-in heat source. It is related with the coating metal material excellent in heat dissipation.

(Background)

In recent years, as the performance and miniaturization of electronic devices and the like progress, the internal temperature rise of the device due to heat generation inside the electronic devices, etc. becomes a problem, and beyond the heat resistance temperatures of ICs, CPUs (semiconductor devices), disks, and motors In addition, there is a risk of impairing the stable operation, and if the internal temperature of the electronic device rises, the semiconductor device may break or fail, which may shorten the life of the electronic device component.

In view of such a situation, the present inventors have started to develop a framework material capable of rapidly dissipating heat generated from an electronic device component having a heat source to the outside to suppress an increase in internal temperature, and the technique described in Japanese Patent No. 3563731. Developed.

This invention is a coating body which improves heat dissipation by forming the heat dissipation coating film which mix | blended the heat dissipation additive on the surface or front and back surface of a base material, and this heat dissipation coating film has electroconductive fillers, such as Ni, in addition to heat dissipation additives, such as carbon black. It mixes and has electroconductivity. This coating material is an infrared ray (wavelength: 4.5 to 15.4 µm) integral heating rate when heated at 100 ° C satisfies the relationship of the following formula (1), and excellent electrical conductivity due to heat dissipation and electromagnetic shielding (microwave parts It is attracting attention as a coating material for).

a × b? 0.42. … (One)

a: Infrared integral emissivity of a coating body having a heat dissipating film formed on its surface

b: Infrared integral emissivity of the coating body having a heat dissipating film formed on the back surface

Since this coating body forms a heat-dissipating coating film containing heat-dissipating additives on one side or both sides of the substrate and exhibits excellent heat radiation characteristics, it is expected to develop a wide range of applications as a framework for various electronic devices in which an internal temperature rise due to a heat source is problematic. . However, further development of this technology requires further improvement in heat dissipation characteristics.

Also, Japanese Patent Application Laid-Open No. 2001-313009 discloses a sealed battery with a convection accelerator film having a convection accelerator film on the outermost surface of the battery for promoting air convection, and a thin polyethylene telephthalate membrane as a convection accelerator film. And polytetrafluoroethylene membranes, polypropylene membranes, and the like.

However, even if the thin film material described in Unexamined-Japanese-Patent No. 2001-313009 is used as a coating film material intended by this invention, the heat dissipation characteristic anticipated by this invention is not exhibited.

In addition, Japanese Patent Application Laid-Open No. 2001-291982 discloses a structure of a sealed structure containing electronic components, and a ventilation path installed in the frame having an intake hole at the lower portion and an exhaust hole at the upper portion thereof, and cooling the inside of the frame by natural air cooling. An air-cooled hermetic electronic device frame is disclosed.

However, this technique improves the surrounding structure of the heating element to control the flow of external air to promote heat dissipation, which is essentially different from the technique of increasing the heat dissipation characteristics of the coating film itself.

(Problem Solving Invention)

The present invention has been made under the above circumstances, and its object is to provide a coating metal material which further improves the heat dissipation characteristics of the coating film by further improving the performance of the heat dissipating coating body as disclosed in Japanese Patent No. 3563731.

(Means to solve the task)

The coating metal material of this invention which can solve the said subject is a coating metal material in which at least 1 layer of coating film is formed in the at least single side | surface of a metal base material, The outermost layer of the said coating film is a porous which has a pore of 1-1000 nm opened to the surface. The particles are contained in a state in which at least a part is exposed from the surface of the outermost layer.

It is preferable that the outermost layer of the coating metal material of this invention is 0.5-4 micrometers in thickness, and the average particle diameter (y) of porous particle is 1-8 micrometers, and satisfy | fills the relationship of "x <y". Moreover, the coating film layer containing a radioactive additive is formed in the lower surface side of this outermost layer, and when the coating metal body is heated at 100 degreeC, the integral emissivity of infrared rays (wavelength 4.5-15.4 micrometers) shows 0.6 or more, It is preferable to have excellent heat dissipation characteristics, and to reduce the surface resistance to 100 Ω or less by incorporating a conductive filler such as Ni into the coating film is also preferable because it exhibits an electromagnetic shielding effect.

The coated metal body of this invention which has such a characteristic can utilize extremely effectively for the frame body of the electronic device which has a heat source especially. In addition, the coated metal body of the present invention can be extremely effectively utilized as at least a part of an outer wall of an electronic device component incorporating a heat source.

The coating metal material of this invention is a state in which the porous particle which has a pore of 1-1000 nm opened to the outermost layer of the coating film as mentioned above at least one part of this porous particle exposed from the outermost layer surface of a coating film, and opened the pore. The heat transfer promoting effect to the outside air is effectively utilized by convection imparted to the porous particles, thereby exhibiting excellent heat dissipation characteristics. Therefore, it can utilize extremely effectively as a frame material which protects various electronic devices which raise internal temperature by heat generation.

In particular, the porous film is blended into the outermost layer of the coating film, and the coating film containing the heat dissipating additive is formed on the lower layer side. The heat transfer promoting action by the convection of the outermost layer and the thermal radiation characteristics of the lower layer film are combined with each other. Excellent heat dissipation characteristics. In addition, by reducing the electrical resistance of the coating film to 100 Ω or less by mixing a conductive filler in at least one of the coating films, the conductivity is good and excellent performance is also achieved in the electromagnetic wave shielding effect.

(The best form to carry out invention)

Heat generated from internal heat-generating parts such as electronic devices is transferred to a frame (casing) that protects the device by heat conduction, convection, heat radiation, and the like. Therefore, if it is possible to dissipate this heat to the atmosphere quickly without accumulating the heat in the frame, the internal temperature of the frame is not excessively high, so that the internal performance of the electronic device can be protected safely.

Therefore, in Japanese Patent No. 3563731 described above, the frame is made of a plate coated with a heat dissipating coating film to prevent the rise in the internal temperature of the electronic device by dissipating heat generated inside the device to the outside. As described above, the heat dissipating coating film is made of a heat dissipating additive such as carbon black to enhance heat dissipation. It is clarified that the electromagnetic wave shielding effect can also be imparted by adding a conductive filler to the coating film.

In contrast, in the present invention, the use of such a heat dissipating additive is not excluded, but the main body of the heat dissipation action is contained in the outermost layer of the coating film, that is, exhibited by the porous particles having pores of 1 to 1000 nm open to the surface. It has a characteristic to let. That is, when the porous particles having pores of a predetermined size opened on the surface are contained in a state where a part thereof is exposed from the surface of the outermost layer of the coating film, the exposed pores of the porous particles convex to the outside air and exhibit excellent heat transfer effect. It was confirmed that the heat dissipation characteristics were further improved.

As described above, the reason why the pores of a predetermined size opened on the surface of the porous particles exhibit unique heat dissipation characteristics is not clear at present. However, as can be clearly seen from the examples described later, in the fine particles having an average particle diameter of the opened pores of less than 1 nm, the heat dissipation characteristics are almost not improved, and the closed pores in which the pores are not opened to the surface. In this case, it is apparent that the pores with an average particle diameter of 1 nm or more have a significant effect on the heat dissipation characteristics.

In addition, it is important that at least a portion of the porous particles are exposed from the surface of the coating film outermost layer, and the opened pores remain in an open state on the outer surface. For this purpose, it is the simplest method to adjust so that the film thickness (x) of the coating film which comprises an outermost layer and the average particle diameter (y) of the said porous particle satisfy | fill the relationship of "x <y". That is, the fact that the average particle diameter y and the film thickness x of the porous particles satisfy the above relationship means that at least a part of the porous particles is exposed from the surface of the outermost layer coating film. Therefore, the open pores present on the exposed porous particles surface promote heat transfer in the direction of the external atmosphere due to convection, so that the heat dissipation characteristics are more effectively increased.

However, if the average particle diameter (y) of the porous particles becomes too large with respect to the film thickness (x), the porous particles protrude largely from the surface of the outermost layer, and the protruding porous particles easily fall out of the outermost layer with a small frictional force. Preferably, the average particle diameter (y) of the porous particles is about 3/2 to 2 times the film thickness (x), that is, "(3/2) x x y y 2x", and 1/3 to the porous particles. It is preferable to adjust the film thickness and the average particle diameter of the porous particles so that about 1/2 is exposed from the upper surface of the outermost layer. However, when the particle size distribution of the porous particles is narrow, particles having a higher ratio can be exposed on the surface of the outermost layer.

The size of the pores opened on the surface of the porous particles is very important because the heat transfer efficiency due to convection in the outside air direction is increased. As a result of the experiments confirmed by the present inventors, it was confirmed that the size should be at least 1 nm or more. The reason for this is not clear at present, but it was confirmed that the heat dissipation promoting effect intended in the present invention was not exerted in the fine pores smaller than 1 nm. The more preferable average diameter of the pores confirmed by the experiment is 5 nm or more, more preferably 10 nm or more.

The upper limit of the pore average diameter is clearly not present. In the present invention, granular porous particles having these pores are mixed in the outermost layer coating film to exhibit the function. The outermost layer film thickness (x) is preferably about 0.5 to 4 µm, as described later. In the relationship with the thickness (x), the average particle diameter (y) of the porous particles is preferably in the range of 1 to 8 µm. Considering this fact, if the pores are too large, the porous particles become brittle and easily collapsed, so the upper limit of the pore diameter for avoiding such a problem is considered to be about 1000 nm. The upper limit of a more preferable pore diameter is 500 nm, Most preferably, it is about 200 nm.

The pore diameter of the porous particles was measured by nitrogen gas adsorption method using AUTOSORBI, a trade name of AYOSIONIX Co., Ltd., and the average particle diameter of the porous particles, using a micro track 9220 FRA, manufactured by Leed & Northrup. This is the value measured.

Examples of the material usable as the porous particles in the present invention include porous silica, zeolite, some activated carbon, and some alumina.

The porous silica used in the present invention can be prepared, for example, as follows. Sulfuric acid (or hydrochloric acid) is added to an aqueous sodium silicate solution and reacted to obtain silica hydrosol (colloid particles having diameters of several nanometers to several tens of nanometals). The silica hydrosol is gelled to obtain a silica hydrosol, which is washed, dried and calcined to obtain porous silica. Here, the pore size of the porous silica is determined by the size of the silica hydrosol.

In order to obtain the porous particle which satisfy | fills the conditions mentioned above about the pore size, you may select the thing which satisfy | fills the conditions among the existing porous silicas, for example.

The film thickness of the outermost layer is preferably set in the range of 0.5 to 4 µm. If the film thickness is too thin, it is difficult to obtain as many porous particles as necessary for the outermost layer. This is because if the thickness becomes too thick exceeding 4 μm, heat dissipation may be rather hindered by the vehicle resin layer constituting the outermost layer. In consideration of stability and heat dissipation of the porous particles, the more preferable film thickness of the outermost layer is 1 µm or more and 3 µm or less.

In the present invention, as described above, the heat dissipation characteristics are enhanced by utilizing the promoting action of convective heat transfer by the open pores of the porous particles exposed from the surface of the outermost layer of the coating film, so that the pores on the surface of the porous particles exposed to the outermost layer surface It is necessary to keep it open. To this end, it is preferable to use a coating liquid having a low solid content concentration in which the vehicle resin component is sufficiently diluted with a volatile solvent as the coating liquid when forming the porous particle-containing layer.

In other words, when a coating liquid having a high solid content concentration is used, when the coating liquid is applied to the outermost layer of the coating film to form the outermost coating film, the resin penetrating into the pores of the porous particles may be dried and solidified to prevent the pores. When the coating liquid having a low solid content concentration is used, the amount of resin remaining after drying and solidification is small, so that there is no fear of blocking the pores to the extent that a resin film is formed on the inner wall surface of the pores.

Therefore, when forming an outermost layer coating film, it is good to use the low concentration coating liquid of 10 mass% or less, More preferably, 7.5 mass% or less, Most preferably, 5 mass% or less by the density | concentration of resin solid content except a porous particle. . Using such a low concentration coating liquid is also advantageous for forming the outermost layer having a relatively thin film thickness of 0.5 to 4 µm. The lower limit of the coating liquid concentration is not particularly present, but considering the separation stability and coating workability of the porous particles in the coating liquid, the concentration of the resin solid except for the porous particles is 1% by mass or more, more preferably about 2% by mass or more. to be.

The mass ratio of the porous particles in the dry coating film may be appropriately adjusted according to the type and thickness of the coating film and the size and pore conditions of the porous particles so as to obtain desired heat dissipation characteristics. Generally, it is good to mix | blend so that about 10% of porous particles may be contained in a dry coating film.

According to the present invention, as described above, porous particles having a predetermined size of pores opened in the outermost layer of the coating film are mixed to increase heat dissipation characteristics by accelerating heat transfer by convection from the surface of the coating film to the outside air direction. . It is of course possible to improve the heat dissipation by utilizing only such an effect, but it is very effective to exhibit such characteristics in combination with the heat dissipation improving technique shown in Japanese Patent No. 3563731.

That is, an underlayer coating film containing the radioactive additive disclosed in Japanese Patent No. 3563731 is formed on the lower layer side of the outermost layer containing the porous particles, and the heat dissipation characteristics of the underlayer coating film are further enhanced. It is also valid. Specifically, a radioactive additive is added to form a lower layer coating film having high heat dissipation characteristics. Porous particles are formed by increasing the integral emissivity of infrared rays (wavelength of 4.5 to 15.4 μm) when the coated metal plate is heated to 100 ° C. to 0.6 or more. In combination with the presence of the outermost layer of the film having improved convective heat transfer performance, the heat dissipation characteristics are further improved.

In addition, said "infrared integral emissivity" means the ease (absorption) of infrared (thermal energy) emission. Therefore, the higher the infrared emissivity, the greater the amount of thermal energy emitted from the coating film. For example, when 100% of the thermal energy applied to an object (in the case of the present invention, a coated metal material) is emitted, the infrared integrated emissivity becomes 1.

In this invention, the infrared integrated emissivity at the time of heating at 100 degreeC as mentioned above is defined. This coincides with the practical ambient temperature in consideration of the fact that the coated metal material of the present invention is usually applied to an electronic device (although depending on the use, but usually used in an ambient temperature of approximately 50 to 70 ° C. and at most about 100 ° C.). In order to make the heating temperature was set to 100 ℃. However, according to the experiments of the present inventors, it was confirmed that the infrared integrated emissivity when heated to 200 ° C. was only about 0.02 (ie 2%) higher than the infrared integrated emissivity of 100 ° C., and was approximately the same.

Although the method of measuring the infrared integrated emissivity employed in the present invention is also clarified in Japanese Patent No. 3563731, it is as follows.

Apparatus: JIR-5500-type Fourier transform infrared spectrophotometer and radiation measuring unit IRR-200 manufactured by Nippon Denshi Corporation

Wavelength Range: 4.5 ~ 15.4㎛

Measurement temperature: Set the heating temperature of test material to 100 ℃

Total number of times: 200 times

Resolution: 16 cm ^-1

Using this apparatus, the spectral radiant intensity (actual value) of the specimen in the infrared wavelength range (4.5-15.4 micrometers) was measured. This measured value was measured by the added / added values of the background radiation intensity and the device irrigation, and an integrated emissivity was calculated by using an emissivity measurement program (emissivity measurement program manufactured by Nippon Denshi Co., Ltd.) to correct them. Details of the calculation method are as follows.

[Equation 1]

Where ε (λ) is the spectral emissivity (%) of the specimen at wavelength λ, E (T) is the spectral emissivity (%) of the specimen at temperature T (° C.), and M (λ, T) is the wavelength λ, The spectral radiant intensity (actual value) of the specimen at the temperature T (° C.), A (λ) is the device irrigation, and K _FB (λ) is the spectral radiant intensity of the fixed background (background unchanged by the specimen) at the wavelength λ. , K _TB (λ, T _TB ) is the spectral radiant intensity of the trap blackbody at wavelength λ, temperature T _TB (℃), and K _B (λ, T) is the spectral radiation of black body at wavelength λ, temperature T (℃) Intensity (calculated from Frank's theoretical formula), λ1, and λ2 mean the ranges of integrated wavelengths, respectively.

Here, A (λ: device irrigation) and K _FB (λ: spectral radiation intensity in fixed background) are measured values of spectral radiation intensity of two black body furnaces (80 ° C and 160 ° C), and at this temperature range. Based on the spectral radiant intensity (calculated from Frank's theoretical formula) of the black body, the following formula was calculated.

[Formula 2]

In the formula, M _{160 ° C.} (λ, 160 ° C.) is the spectral radiant intensity (actual value) from the wavelength λ to 160 ° C., and M _{80 ° C.} (λ, 80 ° C.) is the spectrum from the wavelength λ to 80 ° C. Radiation intensity (actual value), K _{160 ° C} (λ, 160 ° C) is the spectral radiant intensity from the wavelength lambda to 160 ° _C (calculated from Frank's theoretical formula), K _{80 ° C} (λ, 80 ° C) at the wavelength lambda The spectral radiant intensity (calculated from Frank's theoretical formula) to the black body which is 80 degreeC is meant respectively.

In addition, K _TB (λ, T _TB ) is considered in accordance with the calculation of the integral emissivity E (T = 100 ° C.) because the trap black body, which is water-cooled, is placed around the specimen during measurement. Fluctuations of background radiation (meaning background radiation that varies with specimens due to the installation of the trap blackbody. Since the radiation from the surroundings of the specimens is reflected on the surface of the specimens, the actual value of the spectral radiation intensity of the specimens is added to this background radiation. The spectral radiant intensity of the A pseudo black body having an emissivity of 0.96 is used as the trap black body, and the K _TB [(λ, T _TB ): spectral radiant intensity of the trap black body at a wavelength λ and a temperature T _TB (° C.)] is calculated as follows.

K _TB (λ, T _TB ) = 0.96 × K _B (λ, T _TB )

In the formula, K _B (λ, T _TB ) means the spectral radiant intensity of the black body at the wavelength λ, temperature T _TB (° C.).

The coating metal material in which the lower layer coating film containing a radioactive additive was formed is the integral emissivity (the said E (T = 100 degreeC)) of the infrared rays (wavelength 4.5-15.4 micrometers) measured in this way, and the infrared integral radiation rate of the coating metal material in which this heat radiation coating film was formed ( It is preferable that a) is at least 0.6 or more. In the case of a coated metal material having the same heat dissipating coating film formed on the back surface, it is preferable that the product (a × b) of the infrared integrated emissivity (a) and (b) on the front and back surface satisfies 0.6 or more.

That is, the infrared integrated emissivity emitted from the coated metal material is useful as an index indicating the heat dissipation effect of the coated metal material itself, and the value of &quot; 0.6 or higher &quot; exhibits a high radiation characteristic on average in the infrared wavelength range, and thus the present invention In the above, the above values are defined as preferable integral emissivity. More preferably, it is 0.64 or more, Most preferably, it is 0.72 or more.

When implementing this invention, it is more preferable that there are many infrared radiation rates of the one side which becomes the outer surface side of a frame. A coated metal material having an integral emissivity of 0.6 or more, more preferably 0.7 or more, and most preferably 0.8 or more on one side is recommended as the most preferred embodiment in the present invention.

The infrared integrated emissivity hardly affects the constitution of the outermost layer containing the porous particles, and is almost uniformly determined by the constitution of the lower layer containing the radioactive additive. Therefore, as a preferable aspect of this invention which combined this lower layer coating film with the outermost layer film, the said heat radiation characteristic of the said integral emissivity of this lower layer film and the convection heat transfer of an outermost layer film is exhibited.

The most preferred radioactive additive blended in the undercoat is carbon black. In addition, oxides such as Co, Ni, Cu, Mn, Ag, Sn, sulfides, carbides, or the like, or TiO ₂ , ceramics, iron oxide, aluminum oxide, barium sulfide, silicon oxide, or the like can also be used. Preferable compounding quantity of these radioactive additives is 1 mass% or more, More preferably, it is 2 mass% or more by solid content ratio which occupies in a lower layer coating film.

The preferable size at the time of using carbon black as a radioactive additive is 5 nm or more and 100 nm or less in average particle diameter. If the average particle diameter is less than 5 nm, not only the desired heat dissipation characteristics are obtained, but also the stability of the coating material tends to deteriorate, and the appearance of the coating tends to deteriorate. The appearance of the coating film also tends to be nonuniform. Preferably at least 10 nm and at most 90 nm; More preferably, they are 15 nm or more and 80 nm or less. In addition, considering the heat dissipation characteristics, paint stability, uniformity of appearance after coating, and the like, the optimum average particle diameter of carbon black is in the range of approximately 20 to 40 nm.

The type of resin (base resin for forming a heat dissipation film) used as the vehicle component of the outermost layer coating film and the above-described lower layer coating film is not particularly limited from the viewpoint of heat dissipation characteristics, but an acrylic resin, urethane resin, polyolefin resin, poly Ester resins, fluorine resins, silicone resins, mixtures thereof, modified resins and the like can be suitably used. However, since the coated metal material of the present invention is used as a framework for electronic devices, corrosion resistance and workability are often required along with heat dissipation characteristics. Thus, the base resin is a non-hydrophilic resin (specifically, the contact angle with water is 30 ° C. or higher). (More preferably, 50 ° C. or higher, still more preferably 70 ° C. or higher). Such non-hydrophilic resins also depend on the degree of mixing, the degree of modification, and the like, but for example, polyester resins, polyolefin resins, fluorine resins, silicone resins and mixtures or modified resins thereof are preferable, and among them, polyester resins and the like are particularly preferred. Modified resins (thermosetting polyester-based resins or unsaturated polyester-based resins such as epoxy-based polyester resins and polyester-based resins in which a phenol derivative is introduced into the skeleton).

To these resins, crosslinking agents, such as a melamine type compound and an isocyanate type compound, can be added as needed.

In addition, other additives such as rust preventive pigments, antistatic agents, weather resistance improving agents, and the like may be added to the outermost layer film or the lower layer film within a range that does not impair the effect of the present invention. Among other additives, conductive fillers are preferably mentioned as additives that provide excellent performance by blending on the lower coating layer side.

That is, since the electronic device component to which the coated metal material of the present invention is applied may cause electromagnetic interference to the outside in addition to the problem of heat dissipation, it is preferable that the coated metal material of the present invention used as a frame for these electronic devices has electromagnetic shielding properties. For this purpose, it is recommended to provide an electroconductive shielding property by providing a conductive filler by mixing conductive fillers with one or both of the outermost layer and the lower layer (preferably in the lower layer).

Conductive fillers used for this purpose include Ag, Zn, Fe, Ni. Metal compounds, such as Cu, and metal compounds, such as FeP, are mentioned. Especially preferred is Ni. Although the shape is not specifically limited, In order to provide the outstanding electroconductivity with a small compounding quantity, it is good to use the thing of scale-like form. The compounding amount of the conductive filler is in the range of 5 to 50% by mass in terms of the proportion (solid content) of all the components constituting the coating film, including a crosslinking agent, a heat dissipating additive, and other additives added according to the kind of base resin to be used and if necessary. It is good to do. If it is less than 5%, a desired conductivity imparting effect cannot be obtained, and therefore it is preferable to mix it with 15% or more, more preferably 20% or more. However, when the amount of electroconductive filler exceeds 50 mass%, the workability of a coating film will fall. In particular, when applied to a site where high bending workability is required as a coated metal plate, it is preferable to suppress the content to 40% by mass or less, more preferably 35% by mass or less in order to ensure excellent workability.

As an index of electroconductivity, it is good to refer to electrical resistance of 100 ohms or less, More preferably, it is 10 ohms or less. Here, the electrical resistance can be measured by the following method.

Mitsubishi Chemical Corporation's "Lone Star EP" and the probe used a Mitsubishi Chemical Corporation two-probe probe (MCP-TP01). In the measurement, the resistance (Ω) of the specimen is measured by placing two copper plates each having a thickness of 0.8 mm and a size of 20 mm between the probe and the measurement sample so that the copper plates do not contact each other.

Moreover, in this invention using a metal as a base material, it is also effective to mix | blend a rust preventive agent with the additive of that excepting the above. Specific examples thereof include silica compounds, phosphate compounds, phosphite compounds, polyphosphate compounds, sulfur organic compounds, benzotriazoles, tannic acid, molybdate compounds, tungstate compounds, vanadium compounds, and silane couplings. The agent etc. can be mentioned, These can be used individually or in combination. Particularly preferred is a combination of a silica compound (such as calcium ion exchange silica) and a phosphate compound, a phosphite compound, a polyphosphate compound (such as tripolyphosphate), and a silica compound: (phosphate compound, It is recommended to use a phosphite type compound or polyphosphate type compound together in the range of 0.5-9.5: 9.5-0.5 (more preferably 1: 9-9: 1) by mass ratio. By controlling in such a range, the coating film which has the outstanding corrosion resistance and workability can be obtained.

As mentioned above, although the coating film which characterizes the coating body of this invention was mentioned above, the most important point of this invention specified the coating film, also the outermost layer coating layer, or this and lower layer coating film, The kind of metal base material from which a coating film is formed is especially It is not limited. Therefore, as the metal substrate used in the present invention, the most representative steel sheet, specifically, cold-rolled steel sheet, hot-rolled steel sheet, electrogalvanized steel sheet (EG), hot-dip galvanized steel sheet (GI), alloyed hot-dip galvanized steel sheet (GA), Al -Steel plate such as Zn plated steel sheet, various plated steel sheet such as Al, stainless steel sheet, non-ferrous metal sheet, etc. can all be used, and base materials other than metal sheet, specifically, pipe, wire, bar, release material, etc. can be used. have.

The metal material may be subjected to a surface treatment such as chromate treatment or phosphate treatment for the purpose of improving corrosion resistance, adhesion of the coating film, or the like, or may be a non-chromate metal material in consideration of environmental pollution. In any case, it is included in the technical scope of the present invention.

The coating body of this invention can be manufactured by apply | coating the paint containing the component mentioned above to the surface of a base material by a well-known coating method, or drying it, or heat-baking. Although the coating method is not particularly limited, for example, the surface is cleaned and coated with a roll coating method, a spraying method, a carton coating method, etc. on the surface of the substrate subjected to pre-painting treatment (for example, phosphate treatment, chromate treatment, etc.) if necessary. And drying through a hot air drying furnace or baking.

In the case of forming a multi-layered coating film formed of a lower layer coating film under the outermost layer coating film, it is preferable to form the lower layer coating film after the lower layer coating film is dried and solidified by the above-described method. Incidentally, when the drying and solidification are to be performed at the same time after sequentially applying the lower coat and the outermost coat, it is difficult to obtain the outermost coat intended by the present invention due to mutual diffusion or mixing of the lower coat and the outer coat. .

The coating body of the present invention thus obtained has a thin epidermal coating film containing the above-mentioned porous particles in the outermost layer and has excellent convective heat conduction action, and preferably, by forming a lower coating film containing a radioactive additive on the lower layer side thereof, It is possible to have excellent heat dissipation characteristics or, more preferably, to provide an electromagnetic shielding property by mixing a conductive filler on the lower layer side to form a conductive coating film, which can be extremely effectively used as a framework material for protecting and storing electronic devices.

An electronic device component in which the features of the present invention are effectively exhibited is an electronic device component incorporating a heating element in a closed space, and it is preferable that all or part of the outer wall of the electronic component is made of the above-described coated metal material.

Such electronic device parts include information recording products such as CD, LD, DVD, CD-ROM, CD-RAM, PDP and LCD; Electrical, electronic and communication related products such as personal computers, vehicle navigation systems, and vehicle AV; AV equipment such as a projector, a television, a video, and a game machine; Copying apparatuses such as copying machines and printers; A power box cover such as an air conditioner outdoor unit, a control box cover, a vending machine, a refrigerator, and the like can be exemplified as specific examples.

Example

Hereinafter, an Example is given and this invention is demonstrated further more concretely. This invention is not restrict | limited by the following example, Of course, it is also possible to change suitably and to implement in the range suitable for the meaning of the previous and the latter, and all are included in the technical scope of this invention.

(Example)

Electro-galvanized steel plate subjected to chromate treatment (plate thickness; 0.8 mm, Cr deposition amount; 20 mg / m 3 as a base plate, and a coating material containing the additives shown in Table 1 below on one side thereof (using polyester resin as base resin) And a melamine resin was used as the crosslinking agent), followed by baking and drying to form an undercoat.

Next, the polyester resin coating material which mix | blended the microparticles | fine-particles shown in Table 1 was apply | coated, baked and dried, and the outermost layer coating film was formed. In this polyester-based resin coating material, the diameter of the surface of which is opened in each of the resin solid content in the paint is 50% by mass and 7.5% by mass; Porous silica having a large number of pores of about 20 nm (trade name "Mizukasil P-707" manufactured by Mizusawa Chemical Co., Ltd.) or a aperture having a surface open; Zeolites having a large number of pores of about 0.3 nm (trade name "Zeostar KA-100P" manufactured by Nippon Kagaku Co., Ltd.) were blended so as to be 10% by mass in proportion to the dry coating film.

About each obtained coating metal plate, the heat transfer by convection was evaluated by the following method, and the integral emissivity of infrared (wavelength 4.5-15.4 micrometers) when it heated at 100 degreeC was investigated.

[Convective Heat Transfer Evaluation Method]

In order to evaluate the convection and heat transfer performance of each steel sheet, the representative temperature of the steel sheets heated at the same speed in the same direction in the same direction was measured, and the steel sheets were evaluated relative to each other.

principle :

As shown in Fig. 1, the one side of the test plate A and B of the same dimension was heated with the same amount of heat Q0, and the air set at the same temperature T0 and the same speed V1 flowed on the opposite side. If the heat-transmitting performance of the test steel A is superior to the test steel B, the relationship of "TA <TB" is established between the surface temperature TA of the test steel A and the surface temperature TB of the test steel B. In the figure, ha and hb are heat transfer coefficients of the test steels A and B, and A0 is the micro surface area of the test steels A and B (i.e., the surface area ignoring the pore area of the porous particles exposed to the surface, and the same size in the experiment). Since the plate is used, it is the same value).

In addition, the heat passing performance is determined by the radiant heat transfer amount and the convective heat transfer amount, but when the emissivity (ε0) and the air temperature (T0) of the steel sheet become clear, the radiant heat transfer amount (Q2) can be obtained by the following equation, Since the remaining convective heat transfer amount Q1 can be obtained as "Q1 = Q0 and Q2", it is possible to judge whether the improvement of the convective heat transferability is improved.

Q2 = 5.67 × ε0 × A0 × {[(TA + 273) / 100] ⁴ -[(T0 + 273) / 100] ⁴ }

From the said Table 1, it can think as follows.

The code | symbol 1 is a blank material which used the electro galvanized steel sheet in which no coating film was formed as it is. Reference numeral 2 is a coating metal plate composed of only a lower layer coating containing radioactive additives related to the prior application of Japanese Patent No. 3563731. It has a high heat radiation rate and good heat dissipation, and has a 6.3 DEG C or a lower temperature (heat dissipation) effect than a blank material. Could get

Reference numeral 3 denotes an embodiment of the present invention in which a lower-layer coating film having thermal radiation is formed and an outermost coating film that satisfies the requirements of the present invention is formed thereon. Could get

Reference numeral 4 is an example of using a coating resin for forming the outermost layer coating film with reference to symbol 3, which has a high resin solid content concentration. The effect of forming the outermost layer coating film is not exhibited because the pores of the porous particles are blocked with resin. Did. In addition, the code | symbol 5 and 6 used the zeolite which has micropore whose average pore diameter which has a pore as a porous particle does not reach the size prescribed | regulated by this invention, and heat dissipation worsened than the code | symbol 2 which has only a lower layer coating film. This is considered to be because the zeolite has no heat dissipation effect due to convective heat transfer and the thermal radiation of the lower layer coating film is inhibited by the outermost layer coating film containing the zeolite.

In addition, the thermal emissivity depends only on the lower layer coating film, and the thermal emissivity having the same structure as the lower layer coating code 2 to 6 has a constant value regardless of the outermost layer coating film.

According to the present invention, not only a coating metal material having excellent heat dissipation characteristics can be obtained, but also a coating metal material excellent in conductivity and electromagnetic shielding effect can be obtained.

Claims (6)

A coated metal material on which at least one layer of coating film is formed on at least one side of the metal substrate, wherein the outermost layer of the coating film contains porous particles having pores of 1 to 1000 nm that are open on the surface in a state where at least part of them is exposed to the surface layer side. Painted metal material with excellent heat dissipation, characterized in that there is. The outermost layer has a layer thickness (x) of 0.5 to 4 µm, an average particle diameter (y) of the porous particles of 1 to 8 µm, and satisfies a relationship of "x <y". Painted metal material with excellent heat dissipation. The coating film layer containing a radioactive additive is formed in the lower side of the said outermost layer, The integral emissivity of infrared rays (wavelength 4.5-15.4 micrometers) at the time of heating a coating metal material at 100 degreeC is 0.6 or more, It is characterized by the above-mentioned. Painted metal material with excellent heat dissipation. The coated metal material according to claim 1, wherein the coated metal material has a surface resistance of 100 Ω or less. The coated metal material according to claim 1, wherein the coating film is made of a polyester resin or a modified resin of a polyester resin. The coated metal material according to claim 1, wherein the porous particles are porous silica or zeolite.

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