JP2005001393A - Coated element for electronic instrument member showing excellence in heat radiation and self-cooling, and electronic instrument part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated element for an electronic instrument member which can reduce a temperature of an inner portion of an electronic instrument and control a temperature increase of the coated element itself while satisfying the intrinsic properties required for the electronic instrument member (such as air-tightness for water proof, dust proof, and the like), small-sized and light-weighted. <P>SOLUTION: In the coated element for the electronic instrument member, both the right and reverse surfaces are covered with coating films, and at least the right surface of the substrate is covered with a heat radiation film having a heat radiation property or a heat radiation film containing no conductive filler characterized in that the integration emissivity (wave length of 4.5 to 15.4μm) of infrared radiation of the coated element heated at 100°C satisfies the following formula (4): b≤0.9(a-0.05), and the formula(5):(a-0.05)×(b-0.05)≥0.08 excluding a×b≥0.42 wherein a is the integration emissivity of infrared radiation of the coated element the right surface of which is covered with the heat radiation film, and b is the integration emissivity of infrared radiation of the coated element the reverse surface of which is covered with the heat radiation film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a coating body for an electronic device member that is useful as a housing for electronic, electrical, and optical equipment (hereinafter, may be represented by electronic equipment) and that has excellent heat dissipation and self-cooling properties; The present invention relates to a coating composition useful for forming a coated body excellent in these characteristics. The coated body of the present invention is extremely excellent in heat dissipation characteristics and self-cooling properties, and is in the information recording field such as CD, LD, DVD, CD-ROM, CD-RAM, PDP, LCD; personal computers, car navigation systems, car AVs, etc. Suitable for electrical / electronic / communication-related fields, AV equipment such as projectors, televisions, videos, game machines, etc .; copiers such as copiers and printers; power supply box covers for air conditioner outdoor units, control box covers, automatic It can be used as a housing for various electronic equipment members such as a vending machine and a refrigerator. Furthermore, the coated body of the present invention can be used as a chromium-free coated body containing no harmful hexavalent chromium, and has corrosion resistance and coating film adhesion comparable to a chromate-treated steel sheet. This is extremely useful in that it can provide a chromium-free painted body that also has processability.

  In recent years, with higher performance and smaller size of electronic / electrical / optical equipment, etc., the amount of heat generated inside the chassis of electronic equipment has increased (higher temperature), causing problems such as higher temperature (inside electronic equipment) Higher heat). The internal temperature of electronic equipment is usually about 40 to 70 ° C at ambient temperature, and may be as high as about 100 ° C. However, this will exceed the heat resistance temperature of ICs, CPUs (semiconductor elements), disks, motors, etc. It has been pointed out that this will hinder stable operation. Further, when the temperature rises, the semiconductor element breaks and breaks down, and there is a problem that the life of the electronic equipment component is reduced.

  Therefore, as a heat dissipation means to reduce the internal temperature of the electronic equipment (heat dissipation), heat dissipation from the heat sink, heat pipe, etc. to the housing of the electronic equipment (case body, frame, shield case, back panel of liquid crystal etc.) A method of attaching parts has been proposed. However, this method can only obtain an effect of diffusing the heat released from the heat source (heating element) inside the electronic device to the entire housing, and in particular, when the volume of the housing is small, the desired heat dissipation effect. Cannot be obtained. In addition, it takes time to install the heat-dissipating parts, and it is inappropriate to apply to electronic devices that are becoming smaller and cheaper. It is.

  In addition, a method has been proposed in which a metal plate (painted body) is used for a housing of an electronic device, a hole is formed in the metal plate, a fan is attached, and heat is radiated using convection. However, since electronic devices are generally vulnerable to water and dust, they are difficult to apply depending on the application, and, as with the heat sinks described above, there are problems in terms of increasing the cost of components, securing labor and securing the mounting location, etc. There is.

  Therefore, it is possible to achieve a reduction in internal temperature of the electronic equipment (heat dissipation characteristics) while satisfying the original characteristics required for the electronic equipment (ensure airtightness associated with waterproofing / dustproofing, miniaturization / lightening). There is an urgent need to provide a new housing for electronic device members.

  On the other hand, in addition to the heat dissipation characteristics described above, the housing of the electronic device is also required to suppress the temperature rise of the housing itself. This is because it is possible to prevent the risk of burns from being touched by the consumer while the electronic device product is in operation, and to provide a safe product. This “characteristic for suppressing the temperature rise of the housing of the electronic device itself” is called “self-cooling” in the present invention in order to distinguish it from the “heat dissipation” described above. In order to obtain a housing that is excellent in both of these characteristics, the heat dissipation measures described above (such as attaching heat sinks and heat pipes and heat sinks, and mounting fans by drilling holes in metal plates) A similar problem is seen. Therefore, provision of a housing having both of these characteristics is also eagerly desired.

  In addition, focusing on the substrate side, conventionally, the substrate has been subjected to chromate treatment from the viewpoint of corrosion resistance, coating film adhesion, etc. However, there is a problem of environmental pollution due to the use of a large amount of harmful hexavalent chromium. It is getting serious. Therefore, instead of harmful chromate treatment, it is required to cope with chromium-free non-chromate treatment. However, it is known that when the chromate treatment is not performed, the corrosion resistance, coating film adhesion, and workability are also poor. Therefore, it is a chromium-free coated body that is excellent in corrosion resistance, coating film adhesion, and workability without being subjected to chromate treatment, and also has excellent heat dissipation and self-cooling properties as described above. The provision of a housing for members is eagerly desired.

  The present invention has been made by paying attention to the above circumstances, and its purpose is a coated body used as a casing of an electronic device, which is associated with the original characteristics (waterproof / dustproof, etc.) required for an electronic device member. A new painted body that can achieve a reduction in internal temperature of the electronic equipment (heat dissipation characteristics) while satisfying airtightness, miniaturization, and weight reduction; and a characteristic that suppresses the temperature rise of the painted body itself Coated body for electronic equipment members with excellent (self-cooling); Furthermore, it has excellent corrosion resistance and coating film adhesion, and has good workability, and is a chromium-free coated body for electronic equipment parts; Electronic equipment parts coated with a coated body with characteristics; a coating composition applied to a substrate with a chromium-free base treatment, excellent in heat dissipation, corrosion resistance, coating adhesion, and workability Paint composition; and assessing the heat dissipation of the subject And to provide a heat dissipation property evaluation apparatus.

The “coating body for electronic device members having excellent heat dissipation and self-cooling properties” according to the present invention that has solved the above problems has a coating film coated on the front and back surfaces of the substrate, and at least the surface of the substrate. , A heat-dissipating coating film having a heat dissipation property and coated with a heat-dissipating coating film that does not contain a conductive filler,
The integral emissivity of infrared rays (wavelength: 4.5 to 15.4 μm) when the coated body is heated to 100 ° C. satisfies the following expressions (4) and (5) (provided that a × b ≧ 0. (Excluding 42).
b ≦ 0.9 (a−0.05) (4)
(A−0.05) × (b−0.05) ≧ 0.08 (5)
a: Infrared integrated emissivity of a coated body with a heat dissipation coating coated on the surface
b: Infrared integrated emissivity of a coated body having a heat radiation coating coated on the back surface

  In the coated body of the present invention, it is recommended as a preferred embodiment that the heat dissipation film contains at least 50 to 70% by mass of titanium oxide as a heat dissipation additive and satisfies a film thickness of 25 to 30 μm.

A specific configuration for obtaining such a coated body excellent in “heat dissipation and self-cooling” is that the front and back surfaces of the substrate are coated with a coating film, and at least the surface of the substrate has heat dissipation. It is a coated body coated with a heat dissipation coating that is a heat dissipation coating and does not contain a conductive filler,
The said heat-radiation coating film contains a black heat-radiative additive, and has a summary in the place which satisfies the following Formula (6).
(X-3) × (Y−0.5) ≧ 3 (6)
In formula, X is content (mass%) of the black heat dissipation additive contained in a heat dissipation coating film,
Y means the thickness of the heat radiation coating film (μm).

  Here, X (content of black heat dissipating additive contained in heat dissipation coating) satisfies 4 ≦ X <15 [formula (7)]; Y (coating thickness) satisfies Y> 1 μm. What is satisfied: Further, the average particle size of the black additive satisfies 5 to 100 nm; and the black additive is carbon black is useful for obtaining better heat dissipation.

  In the above-described coated body of the present invention, if a non-hydrophilic resin (preferably a polyester resin) is used as the resin for forming the heat radiation coating film, the corrosion resistance is improved, which is a preferable embodiment.

  Furthermore, in the present invention, the above-described heat-dissipating coating film coated with a clear coating film is useful because it can improve the anti-fouling property and fingerprint resistance.

  The painted body of the present invention can also be applied to a chromium-free painted body. That is, it is a preferable aspect that the substrate is subjected to a chromium-free ground treatment, and the heat radiation coating further contains a rust preventive agent. Specifically, the component for forming the heat radiation coating film is composed of a polyester resin in which an epoxy-modified polyester resin and / or a phenol derivative is introduced into a skeleton, and a crosslinking agent (preferably an isocyanate resin and / or a melamine resin). It is recommended to contain a combination of both of them), whereby excellent corrosion resistance [area ratio of appearance abnormal part in salt spray test corrosion resistance test (72 hours) defined in JIS-Z-2371]: 10% or less], coating film adhesion (the state of peeling of the coating film after taping the bent portion), workability (number of cracks in the adhesion bending test defined in JIS K 5400: 5 or less) Can do. Furthermore, if the coating film is coated on the coating film, the anticorrosive agent can be prevented from being eluted, so that the corrosion resistance [salt spray specified in JIS-Z-2371 is improved. This is very useful because an area ratio of an appearance abnormality portion in a test corrosion resistance test (120 hours): 10% or less] is obtained. Here, if the coating film coated on the coating film is a clear coating film, the scratch resistance and fingerprint resistance can be further improved.

  The various coated bodies as described above are useful as those used as housings for electronic device parts.

  On the other hand, the coating composition for electronic device members of the present invention that has solved the above-mentioned problems is a coating composition used for the coating body as described above, and contains 3 mass of black additive with respect to the coating film forming component. The coating composition is excellent in heat dissipation and self-cooling properties if such a coating composition is used. . Here, what the average particle diameter of the said black additive is 5-100 nm is a preferable aspect.

  Furthermore, the present invention relates to a coating composition applied to a substrate subjected to a chromium-free base treatment, and a polyester in which an epoxy-modified polyester resin and / or a phenol derivative is introduced into a skeleton with respect to a coating film forming component A coating composition for electronic device members containing 35% by mass or more of a resin, 2 to 25% by mass of a rust inhibitor, 1 to 20% by mass of a crosslinking agent, and more than 3% by mass of a black additive is also included in the present invention. Included within range. Here, it is preferable that the said crosslinking agent contains a melamine type resin in the ratio of 5-80 mass parts with respect to 100 mass parts of isocyanate type resins. Moreover, the average particle diameter of the black additive is 5 to 100 nm, and the use of carbon black is recommended. If a coating composition satisfying such a composition is used, a chromium-free coating film excellent in heat dissipation, self-cooling property, corrosion resistance, coating film adhesion, and workability can be formed.

  Further, according to the present invention, there is provided an electronic device component having a heating element in a closed space, wherein the whole or a part of the outer wall of the electronic device component is composed of the above-described coated body for an electronic device member of the present invention. (For example, information recording products such as CD, LD, DVD, CD-ROM, CD-RAM, PDP, LCD, etc .; electrical / electronic / communication related products such as personal computers, car navigation systems, car AVs; projectors, televisions, videos, game machines, etc. AV equipment; copiers such as copiers and printers; power supply box covers such as air conditioner outdoor units, control box covers, vending machines, refrigerators, etc.) are also included within the scope of the present invention.

  Since the coated body of the present invention is configured as described above, while satisfying the original characteristics required for electronic device members (ensure airtightness associated with waterproofing / dustproofing, miniaturization / weight reduction), To provide a coating for an electronic device member that can also have a reduced internal temperature of the device member (heat dissipation property) and also has an excellent property (self-cooling property) that suppresses the temperature rise of the coating body for the electronic device member itself. I was able to. The coated body of the present invention is particularly in the field of information recording such as CD, LD, DVD, CD-ROM, CD-RAM, PDP, LCD, etc .; other fields related to electrical / electronic / communication such as personal computer, car navigation system, car AV, etc. AV equipment such as projectors, TVs, videos, game machines; copiers such as copiers and printers; power supply box covers for air conditioner outdoor units, control box covers, vending machines, refrigerators, etc. be able to.

  The present inventors have reduced the internal temperature of the electronic device while satisfying the original characteristics required for the electronic device (sealing, dustproof, etc., ensuring airtightness, miniaturization / weight reduction, low cost, etc.) In order to provide a new coated body for electronic equipment members that can also achieve heat dissipation characteristics), in particular, it has been intensively studied focusing on improving the heat dissipation of the coated body itself. As a result, it was found that the intended purpose can be achieved if a predetermined coating film is coated on the front and back surfaces of the substrate.

  The mechanism is that "the heat (radiant heat) emitted from the heat source (heating element) inside the electronic device is absorbed (radiated) by the coating film on the back surface, and this heat is radiated from the heat radiation coating film on the surface". The greatest feature is that the idea of the so-called “heat-through method” has been successfully applied to electronic device members. Such a “heat-through method” concept is applied to electronic equipment members, and the amount of heat released from the electronic equipment is absorbed from the back side of the board to the front side of the board and then radiated. It is not known and is new. In the present invention, the outside air side as viewed from the painted body is referred to as “front surface”, and the inside of the painted body is referred to as “back surface”.

  The coated body of the present invention is a coating in which a coating film is coated on the front and back surfaces of the substrate, and at least the surface of the substrate is coated with a heat radiation coating film having a heat dissipation property and containing no conductive filler. As an index representing “excellent self-cooling”, ΔT2 (degree of suppression of temperature rise of the coated body itself) shown in the following (III) or the formula (4) shown in the following (IV) [b ≦ 0. 9 (a-0.05)]; and as an index representing “excellent heat dissipation” in the second coated body, the following formula (5) [(a−0.05) × (B−0.05) ≧ 0.08] is satisfied.

  First, the self-cooling index will be described.

  Among these, the formula (4) is defined as an index indicating a heat dissipation effect that increases the infrared emissivity of the front surface compared to the infrared emissivity of the back surface and moves the heat absorbed by the coated body to the outside air; On the other hand, ΔT2 defines the heat dissipation effect in a practical level painted body that simulates the use of electronic equipment members.

  Thus, both of them are useful as indexes representing “self-cooling” and have a good correlation. For reference, FIG. 3 shows a graph in which the results of Examples described later are plotted. The vertical axis in FIG. 3 represents the calculated value of the left side (0.9a-b) (hereinafter referred to as the Q value) in the equation (0.9a−b ≧ 0.05) obtained by modifying the above equation (4). Yes).

  For those satisfying such self-cooling properties, the temperature rise of the coated body itself can be suppressed. Therefore, even when the painted body is used as a housing for an electronic device, It is possible to provide electronic devices that are safe from the viewpoint of the operator. And since the said coating body also has favorable heat dissipation, the electronic device member which has these both characteristics is very useful at the point which brings further expansion of a use.

  Hereinafter, the characteristics (III) to (V) will be described.

(III) ΔT2 (= T2 _B −T2 _A ) ≧ 0.5 ° C.
Here, T2 _A uses the heat dissipation evaluation apparatus shown in FIG. 1 below, the present invention coated body paint body temperature when measured as a test material; T2 _B is similarly heat dissipation of the FIG. 1 It means the substrate temperature when using an evaluation apparatus and using a substrate not coated with a coating film as a test material. Moreover, the difference ((DELTA) T2) of the temperature when using a test material and the temperature when using the uncoated original board which does not give a coating film was computed.

  ΔT2 was measured five times for each specimen, and the average value of three points of data excluding the upper limit and the lower limit was determined as ΔT2 in the present invention.

  The above ΔT2 shows how the temperature rise of the coated body itself when the electronic device is in operation when the coated body of the present invention is used as compared with the case of using the substrate (the bare original plate not coated with the coating film). An index (self-cooling property) indicating whether it can be suppressed is determined. In the present invention, as the device for measuring ΔT2, in particular, the heat dissipation evaluation device unique to the present invention shown in FIG. 1 is used.

  In order to obtain excellent self-cooling properties, the larger ΔT2 is more preferable. They are 1.0 degreeC or more, 1.5 degreeC or more, 2.0 degreeC or more, and 2.5 degreeC or more in the preferable order of (DELTA) T2.

(IV) Formula (4): b ≦ 0.9 (a−0.05)
In the formula, a and b are integral emissivities of infrared rays (wavelength: 4.5 to 15.4 μm) (hereinafter simply referred to as “ In the case of “infrared integrated emissivity” or “infrared emissivity”, the infrared integrated emissivity (a) on the front surface and the infrared integrated emissivity (b) on the back surface are meant respectively. This infrared integrated irradiation rate is measured by the method described later, and the infrared integrated irradiation rate on the front surface or the back surface can be measured separately.

  The above-mentioned “infrared integrated emissivity” means, in other words, ease of emission (easy absorption) of infrared rays (thermal energy). Therefore, the higher the infrared emissivity, the greater the amount of heat energy released (absorbed). For example, when 100% of the thermal energy applied to an object (in the present invention, a painted body) is emitted, the infrared integrated emissivity is 1.

  In addition, in the present invention, the infrared integrated emissivity when heated to 100 ° C. is determined, but this is because the coated body of the present invention is used for electrical equipment (although it differs depending on members, etc., the normal ambient temperature is generally The heating temperature is set to 100 ° C. in consideration of the application to 50 to 70 ° C. and a maximum of about 100 ° C.). However, the infrared integrated emissivity hardly changes even when heated to 200 ° C., and the infrared integrated emissivity when heated to 200 ° C. is generally about 0.02 higher than the infrared integrated emissivity of 100 ° C., It is confirmed by experiments that they are almost identical.

The method for measuring the infrared integrated emissivity in the present invention is as follows.
Apparatus: “JIR-5500 type Fourier transform infrared spectroscopy” manufactured by JEOL Ltd.
Photometer "and radiation measurement unit" IRR-200 "
Measurement wavelength range: 4.5 to 15.4 μm
Measurement temperature: set the heating temperature of the sample to 100 ° C. Integration count: 200 times Resolution: 16 cm ⁻¹

  Using the above apparatus, the spectral radiant intensity (measured value) of the sample in the infrared wavelength region (4.5 to 15.4 μm) was measured. In addition, since the measured value of the sample is measured as a numerical value obtained by adding / adding the background radiation intensity and the instrument function, an emissivity measurement program [emissivity manufactured by JEOL Ltd.] is used for the purpose of correcting these values. The integral emissivity was calculated using a measurement program. Details of the calculation method are as follows.

Where
ε (λ): Spectral emissivity of sample at wavelength λ (%)
E (T): Integrated emissivity (%) of sample at temperature T (° C.)
M (λ, T): Spectral radiant intensity of sample at wavelength λ and temperature T (° C)
(Actual value)
A (λ): Instrument function K _FB (λ): Fixed background at wavelength λ (depending on sample)
Spectral radiant intensity of unchanging background K _TB (λ, T _TB ): Wavelength of λ, trap black body at temperature T _TB (° C)
Spectral radiant intensity K _B (λ, T): Spectral radiant intensity of a black body at wavelength λ and temperature T (° C.)
(Calculated value from blank theoretical formula)
λ ₁ , λ ₂ : Means the range of wavelengths to be integrated, respectively.

Here, A (λ: instrument function) and K _FB (λ: spectral radiant intensity of fixed background) are measured values of spectral radiant intensity of two blackbody furnaces (80 ° C., 160 ° C.), and Based on the spectral radiant intensity of the black body in the temperature range (calculated value from the theoretical formula of the blank), it is calculated by the following formula.

Where
M ₁₆₀ ° C. (λ, 160 ° C.):
Spectral radiant intensity of 160 ° C blackbody furnace at wavelength λ (actual measurement)
M ₈₀ ° C (λ, 80 ° C):
Spectral radiation intensity of 80 ° C blackbody furnace at wavelength λ (actual measurement)
K ₁₆₀ ° C. (λ, 160 ° C.):
Spectral radiation intensity of 160 ° C blackbody furnace at wavelength λ
(Calculated value from blank theoretical formula)
K ₈₀ ° C (λ, 80 ° C):
Spectral radiant intensity of black body furnace at 80 ° C at wavelength λ
(Calculated value from blank theoretical formula)
Means each.

In calculating the integral emissivity E (T = 100 ° C.), K _TB (λ, T _TB ) is taken into consideration when a trapped black body cooled with water is placed around the sample. Because of that. By installing the trap black body, variable background radiation (meaning background radiation that varies depending on the sample. Since the radiation from the periphery of the sample is reflected on the sample surface, the measured value of the spectral radiant intensity of the sample is Spectral radiation intensity (which appears as a numerical value with background radiation added) can be controlled low. The above trap black body uses a pseudo black body with an emissivity of 0.96, and K _TB [(λ, T _TB ): spectral radiant intensity of the trap black body at wavelength λ and temperature T _TB (° C.). ] Is calculated as follows.
K _TB (λ, T _TB ) = 0.96 × K _B (λ, T _TB )
Where K _B (λ, T _TB ) is the black body at wavelength λ and temperature T _TB (° C.).
Means spectral radiant intensity.

  As described above, the above formula (4) is also useful as an index of “self-cooling property” that suppresses the temperature rise of the coated body itself. The above equation is the idea that “the temperature rise of the coated body itself should be suppressed by applying a coating with a higher infrared emissivity on the surface (outside air side) of the substrate than on the back side of the substrate (inside the electronic device)” Based on the above, the relational expression of the infrared emissivity of the front and back surfaces that can ensure the desired self-cooling property (ΔT2 ≧ 0.5 ° C.) is specified.

  When using a painted body for the housing of an electronic device, increasing the infrared emissivity of the inner surface (back surface) of the housing increases the amount of infrared radiation emitted from the heat source inside the electronic device, and the temperature of the painted body itself increases. End up. On the other hand, if the emissivity of the outer surface (surface) of the housing is increased, the amount of infrared rays emitted from the paint body toward the outside air increases, and the temperature of the paint body also decreases. The present invention is based on such knowledge, and various experiments are repeated to define the above equation. According to the present invention, the surface of the substrate is more than the amount of heat absorbed (radiated) on the back side of the substrate. Since the amount of heat radiated from the side increases, the temperature rise of the coated body itself can be efficiently suppressed.

  In this way, there is no known coating body that has a coating film with different heat dissipation characteristics on the front and back surfaces of the substrate, maintains a certain level of heat dissipation characteristics, and suppresses the temperature rise of the coating body. Think of it as new.

  Therefore, in the coated body of the present invention, the greater the difference in the infrared emissivity between a and b, the better the self-cooling property. Specifically, the Q value (= 0.9a−b) is preferably as large as possible, and in a preferable order, 0.13 or more, 0.24 or more, 0.35 or more, or 0.47 or more.

Next, an index representing “excellent heat dissipation” will be described. In the present invention, ΔT1 (= T1 _B −T1 _A ) ≧ 2.6 ° C., or the following (V) formula (5) [(a−0.05) × (b−0.05) ≧ 0.08] Satisfied.

Here, T1 _A is the temperature at the T1 position when the coated body of the present invention is used as a test material using the heat dissipation evaluation apparatus shown in FIG. 1 to be described later; T1 _B is the heat dissipation of FIG. This means the temperature at the T1 position when using a property evaluation apparatus and using a substrate that is not coated with a coating film as a test material.

  The ΔT1 is an index of how the internal temperature of the electronic device can be reduced when the coated body of the present invention is used, compared to the case where a substrate (a bare original plate not coated with a coating film) is used. In the present invention, as the apparatus for measuring ΔT1, in particular, the heat radiation evaluation apparatus unique to the present invention shown in FIG. 1 was used. The apparatus of FIG. 1 can evaluate the heat radiation characteristics of the ambient temperature assumed for applications such as electronic devices (although the ambient temperature varies depending on the type of electronic device member, etc., it is generally about 50 to 70 ° C. and about 100 ° C. at the maximum). It is extremely useful as a device, and this makes it possible to correctly evaluate the heat dissipation effect at a practical level simulating the use of electronic equipment.

FIG. 1 shows a rectangular parallelepiped device having an internal space of 100 mm (vertical) × 130 mm (horizontal) × 100 mm (height). In FIG. 1, 1 is a test material (subject, measurement area is 100 × 130 mm), 2 is a heat insulating material, 3 is a heating element [the bottom area is 1300 mm ² , and the length of the longest straight line that can be drawn within the heating element area. (In FIG. 1, the length of the diagonal line is 164 mm), 5 is a temperature measuring device.

  Of these, a silicon rubber heater is used as the heating element 3 and an aluminum plate (infrared emissivity is 0.1 or less) is used on the silicon rubber heater. In addition, a thermocouple is fixed as the temperature measuring device 5 at a position T1 in FIG. 1 [central portion of the internal space (above 50 mm from the heating element 3)]. The lower part of the thermocouple is covered for the purpose of eliminating the influence of heat radiation from the heating element. Moreover, since the heat insulating material 2 changes the atmospheric temperature in the box depending on the type and usage mode (which also affects heat dissipation), a metal plate having an infrared emissivity of 0.03 to 0.06 [for example, electrogalvanizing Using a steel plate (JIS SECC, etc.), the method of tensioning the heat insulating material is adjusted so that the atmosphere temperature (absolute value temperature) at the T1 position is in the range of about 73 to 74 ° C. by the method described later. In addition, the factors affecting the heat dissipation (for example, the fixing method of the test material) are similarly adjusted so that the ambient temperature (absolute temperature) at the T1 position is in the range of about 73 to 74 ° C.

  Next, a method for evaluating heat dissipation characteristics using the above apparatus will be described.

  In the measurement, the measurement conditions are controlled to a temperature of 23 ° C. and a relative humidity of 60% for the purpose of eliminating variation in data due to outside air conditions (wind etc.).

  First, each test material 1 is installed, the power is turned on, and the hot plate 3 is heated to 140 ° C. After confirming that the temperature of the hot plate is stably 140 ° C. and the temperature at the T1 position is 60 ° C. or higher, the specimen is once removed. When the temperature in the box drops to 50 ° C., the sample material is installed again, and the temperature in the box 90 minutes after installation is measured. Next, the difference (ΔT1) between the temperature when the above-mentioned test material is used and the temperature when an uncoated original plate without a coating film is used is calculated.

  ΔT1 was measured five times for each specimen, and the average value of three points of data excluding the upper and lower limits was defined as ΔT1 in the present invention.

  The larger ΔT1 calculated in this way means that the heat dissipation characteristic is more excellent. It is 2.7 degreeC or more, 3.0 degreeC or more, 3.3 degreeC or more, 3.5 degreeC or more, 3.7 degreeC or more, 4.0 degreeC or more in preferable order.

  In addition, although the parameter | index (target level) of a heat dissipation characteristic changes with kinds etc. of an electronic device, according to this invention, as it mentions later, the black additive contained in a heat dissipation coating film is related with coating film thickness. By appropriately controlling, it is possible to easily adjust to a predetermined heat dissipation characteristic.

(V) Formula (5): (a−0.05) × (b−0.05) ≧ 0.08
The above formula (5) is an index of heat dissipation characteristics in the coated body of the present invention specified by the product of the infrared integrated emissivity of the front and back surfaces, and the left side [(a−0.05) × (b−0.05). )] (There is a case where it is represented by an R value hereinafter) is larger, it indicates that the heat dissipation characteristic (ΔT1) is more excellent. Preferable lower limits are 0.35 (ΔT1, about 2.6 ° C.) and 0.52 (ΔT1, about 3.5 ° C.) in this order.

  The above equation (5) has a good correlation with the above-described ΔT1. For reference, FIG. 4 shows a graph in which the results of Examples described later are plotted.

  Next, a specific configuration for obtaining the coated body will be described.

  In the coated body, a coating film is coated on the front and back surfaces of a substrate, and at least a surface of the substrate is coated with a heat radiation coating film having heat dissipation properties. In order to secure the desired self-cooling property, it is necessary to satisfy the above formula (4) by increasing the infrared emissivity of the front surface as compared with the back surface, and the heat dissipation characteristic is at least the above formula (5). ) Must be satisfied. Thus, since the level of the heat dissipation characteristic requested | required by the front surface and a back surface differs in the 2nd coating body, below, it demonstrates separately.

  First, the “surface heat radiation coating” in the second coated body includes the following aspects (A) and (B).

(A) A black surface heat-dissipating additive (black additive) is mainly added, and the black additive (X) contained in the heat-radiating coating film is controlled in relation to the coating film thickness (Y) . When adding a black additive to the coating film to improve heat dissipation characteristics, X and Y are added so that the addition amount (X) of the black additive and the coating thickness (Y) satisfy the following formula (6). Is appropriately controlled. Specifically, it is as the following (A-1) to (A-3).

(A-1) Formula (6): (X-3) × (Y-0.5) ≧ 3
The above equation (6) defines the relational expression of X and Y for realizing the target level of heat dissipation (ΔT1 ≧ 1.5 ° C.) in the second coated body, and the P value [= ( The larger the X-3) × (Y-0.5)], the better the heat dissipation characteristics. It is 7 or more, 11 or more, 15 or more, 30 or more, 50 or more in a preferable order.

  However, even if the P value is increased too much, the heat dissipation characteristics do not saturate, and only the amount of black additive to be used increases, which is economically wasteful. In addition, the coated body of the present invention is used as a housing for electronic equipment. In consideration of requirements for workability, conductivity, etc., it is recommended that the upper limit of the P value be controlled to 240, 200, 150, 100 in order of preference.

  The black additive used in the present invention is not particularly limited as long as it can impart black color, and typically includes carbon black, but in addition, Fe, Co, Ni, Cu, Mn, Mo, Ag , Sn or the like, sulfide, carbide, black metal fine powder, or the like can also be used. Most preferred is carbon black.

  Here, the addition amount (X) of carbon black in the coating film can be measured by the following method.

  First, a solvent is added to a subject (analysis sample) and heated to decompose organic substances in the subject. The type of solvent to be used varies depending on the type of base resin, and an appropriate solvent may be used as appropriate according to the solubility of each resin. For example, a polyester resin or a urethane resin is used as the base resin. In such a case, the subject may be added to a container (eg, eggplant-shaped flask) to which a sodium hydroxide-methanol solution has been added, and the container may be heated in a 70 ° C. water bath to decompose organic matter in the subject.

  Subsequently, this organic substance is filtered off with a glass filter (pore diameter 0.2 μm), and carbon in the obtained residue is quantified by a combustion infrared absorption method to calculate a carbon black concentration in the coating film.

  Furthermore, the average particle size of the black additive is preferably controlled to 5 to 100 nm. If the average particle diameter of the additive is less than 5 nm, desired heat dissipation characteristics cannot be obtained, the stability of the paint is poor, and the coating appearance is poor. On the other hand, when the average particle diameter exceeds 100 nm, not only the heat dissipation characteristics are deteriorated, but also the appearance after coating becomes non-uniform. Preferably they are 10 nm or more and 90 nm or less; More preferably, they are 15 nm or more and 80 nm or less. In addition to the heat dissipation characteristics, it is recommended that the optimum average particle size of the black additive be approximately 20 to 40 nm considering the stability of the coating film and the appearance uniformity after coating.

(A-2) Formula (7): 4% ≦ X <15%
Assuming that the content X of the black additive exceeds 3%, it is recommended to set it to 4% or more. Here, in order to satisfy the above equation (6), “X> 3%” is premised on that the coefficient on the left side of the equation (X−3) is positive (> 0). Because it is necessary.

  The lower limit of X is determined in order to obtain excellent heat dissipation characteristics and at the same time ensure the characteristics of the coated body itself (paintability, appearance, etc.). Desirable characteristics can be obtained at 3% or less. Absent. Preferable lower limits are 5%, 7%, 8% and 10% in order. On the other hand, the upper limit of X is not particularly limited in relation to the heat dissipation characteristics, but when it is 15% or more, the paintability is deteriorated, coating unevenness occurs, and appearance defects occur. Therefore, the preferable upper limit in consideration of paintability and the like is less than 15%, 13%, and 11% in order.

(A-3) Formula (8): Y> 1 μm
The coating thickness Y of the heat dissipation coating is premised on more than 0.5 μm, and it is recommended that the coating thickness Y exceeds 1 μm. Here, in order to satisfy the above equation (6), “Y> 0.5 μm” is premised on that the coefficient on the left side of the equation (Y−0.5) is positive (> 0). Because it is necessary to be.

  The lower limit of Y is determined in order to obtain particularly excellent heat dissipation characteristics. When Y is 0.5 μm or less, a desired heat dissipation effect cannot be obtained even if a large amount of black additive is added. Preferable lower limits are 3 μm, 5 μm, 7 μm, and 10 μm in order.

  The upper limit of Y is not particularly limited in relation to heat dissipation characteristics, but the coated body of the present invention is intended to be applied to electronic equipment parts, and improvement in workability is also required in relation to the application. In particular, considering prevention of occurrence of cracks and peeling of the coating film during bending, it is recommended to control to 50 μm or less (more preferably, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less).

  Furthermore, it is recommended to control the above Y to 12 μm or less (more preferably, 11 μm or less, and even more preferably 10 μm or less) in order to provide good workability and ensure excellent conductivity.

(B) A mode in which additives other than black additives are mainly added In order to enhance the heat dissipation characteristics of the surface coating film, other additives (typically, at least TiO2) other than black additives are used. In this case, for example, TiO ₂ , ceramics, iron oxide, aluminum oxide, barium sulfate, silicon oxide or the like is used as the other additive. These can be used alone or in combination of two or more. Further, a black additive such as carbon black may be added. The film thickness of the heat dissipation coating can be appropriately determined depending on the type of additive used, etc., so that desired heat dissipation characteristics can be obtained. Recommended.

Specifically, in the case of a TiO ₂ -containing coating film, it is recommended to add approximately 50 to 70% of titanium oxide in the coating film so that the coating film thickness is about 25 to 30 μm. When it is desired to apply a coating film having a metallic appearance, it is recommended that Al flakes and the like are added in an amount of about 5 to 30% and the coating thickness is about 5 to 30 μm.

  Next, the “back coating film” in the second coated body according to the present invention will be described. The above-mentioned “surface coating film” needs to be a heat radiation coating film in order to ensure excellent self-cooling properties, but the “back surface coating film” is not necessarily a heat radiation coating film as long as desired properties are obtained. It is not necessary to. That is, the coated body of the present invention does not include a “single-side coated steel plate” in which the back side of the substrate is not coated (the infrared emissivity of the uncoated base plate is approximately 0.04, and the desired self-cooling property). However, as long as the above expression (4) is satisfied, any coating film can be employed.

  Specifically, other additives other than the black additive and black additive described above are used alone or in combination, and the addition amount and coating thickness are appropriately adjusted according to the emissivity of the surface coating film. A coating film on the back surface can be formed. In addition, when forming the coating film on the back surface using a black additive, the relationship between the X and Y does not necessarily satisfy the above-described formula (6), and the coating film having almost no heat dissipation (the above-mentioned Even if the infrared emissivity of the surface coating is appropriately controlled, the desired self-cooling property can be secured (Nos. 1 and 11 in Table 1 described later). reference).

  Alternatively, it is also possible to employ a coating film in which the above-mentioned additives are not added at all and the coating thickness is controlled within a predetermined range (about 2.5 μm or more) (see Nos. 3 and 7 in Table 1 described later). . This is because a certain degree of heat dissipation characteristics can be obtained only with the resin contained in the coating film.

  Specifically, for example, when a non-hydrophilic polyester resin is used as the coating film-forming resin, the coating film thickness may be adjusted to approximately 2.5 μm or more.

  The basic configuration of the black additive / other additive that forms the coating film on the front and back surfaces of the coated body of the present invention has been described above.

  In addition, the kind of resin (base resin forming the heat radiation coating film) added to the coating film is not particularly limited from the viewpoint of heat radiation characteristics, and acrylic resin, urethane resin, polyolefin resin, polyester resin. Fluorine-based resins, silicon-based resins, mixed or modified resins thereof, and the like can be used as appropriate. However, since the coated body of the present invention is used as a casing for electronic equipment, considering that the improvement of corrosion resistance and workability is required in addition to heat dissipation, the base resin is a non-hydrophilic resin [specifically, The contact angle with water preferably satisfies 30 ° or more (more preferably 50 ° or more, even more preferably 70 ° or more)]. Resins satisfying such non-hydrophilic properties may vary depending on the degree of mixing, the degree of modification, etc., for example, polyester resins, polyolefin resins, fluorine resins, silicon resins, and mixtures or modifications thereof. Among them, polyester resins or modified polyester resins (epoxy modified polyester resins, thermosetting polyester resins such as polyester resins having a phenol derivative introduced into the skeleton, or unsaturated polyester resins) are preferred. ) Is recommended.

Furthermore, in addition to black additives such as carbon black, pigments such as rust preventive pigments and silica may be added to the coating film as long as the effects of the present invention are not impaired. Alternatively, other heat-dissipating additives (for example, at least one of TiO ₂ , ceramics, iron oxide, aluminum oxide, barium sulfate, silicon oxide, etc.) other than the black additive are also used in the present invention. It can be added as long as the action is not impaired.

  Moreover, a crosslinking agent can be added to the said coating film. As a crosslinking agent used for this invention, a melamine type compound, an isocyanate type compound, etc. are mentioned, for example, It is recommended to add these by 1 type or 2 types or more in the range of 0.5-10 mass%.

  The coating film characterizing the coated body of the present invention has been described in detail above. As described above, the most important point of the present invention is that the configuration of the coating film is specified, and the substrate other than the coating film is not particularly limited. Therefore, as a substrate used in the present invention, (1) typically a metal plate, specifically a cold-rolled steel plate, a hot-rolled steel plate, an electrogalvanized steel plate (EG), a hot-dip galvanized steel plate (GI), alloying Hot-dip galvanized steel sheet (GA), 5% Al—Zn plated steel sheet, 55% Al—Zn plated steel sheet, various plated steel sheets such as Al, steel sheets such as stainless steel sheets, known metal plates, etc. can all be applied In addition, (2) a substrate other than a metal plate, specifically, a wire, a bar, a pipe, a ceramic, and the like can be given. Among these, metal materials such as a metal plate excellent in thermal conductivity, and ceramic are preferable.

  The metal plate (1) may be subjected to surface treatment such as chromate treatment and phosphate treatment for the purpose of improving corrosion resistance and adhesion of the coating film. A non-chromated metal plate may be used, and any embodiment is included within the scope of the present invention.

  Here, the configuration of the coated body of the present invention using a non-chromated metal plate will be described.

  First, the substrate is subjected to a chromium-free ground treatment, and the heat radiation coating film (at least the surface) needs to further contain a rust preventive agent. In general, it is known that non-chromate treatment reduces the corrosion resistance, and the use of a rust inhibitor is indispensable for the purpose of improving the corrosion resistance.

  Here, the “chromium-free base treatment” is not particularly limited, and a known base treatment that is usually used may be performed. Specifically, it is recommended that the surface treatment such as phosphate-based, silica-based, titanium-based, zirconium-based is performed alone or in combination.

  In addition, the above rust preventives include silica compounds, phosphate compounds, phosphite compounds, polyphosphate compounds, sulfur organic compounds, benzotriazole, tannic acid, molybdate compounds, tungsten Examples thereof include acid salt compounds, vanadium compounds, and silane coupling agents, and these can be used alone or in combination. Particularly preferred is a combination of a silica-based compound (for example, calcium ion-exchanged silica) and a phosphate-based compound, a phosphite-based compound, or a polyphosphate-based compound (for example, aluminum tripolyphosphate). Compound: (phosphate compound, phosphite compound, or polyphosphate compound) in a mass ratio of 0.5 to 9.5: 9.5 to 0.5 (more preferably 1: It is recommended to use in the range of 9-9: 1). By controlling within this range, both desired corrosion resistance and workability can be ensured.

  In addition, you may use these rust preventives also for the said surface treatment.

  It is also known that the corrosion resistance can be ensured by the use of the above rust preventive agent, but the workability due to the addition of the rust preventive agent is lowered. Therefore, in the present invention, as a component for forming a heat-dissipating coating film, particularly attention is paid to a combination of a resin and a crosslinking agent, and an epoxy-modified polyester resin and / or a polyester resin in which a phenol derivative is introduced into the skeleton, and a crosslinking agent. It is recommended to use a combination of (preferably an isocyanate resin and / or a melamine resin, more preferably a combination of both).

  Of these, epoxy-modified polyester resins and polyester resins in which phenol derivatives are introduced into the skeleton (for example, polyester resins in which bisphenol A is introduced into the skeleton) are superior in corrosion resistance and coating film adhesion compared to polyester resins. .

  On the other hand, the isocyanate-based crosslinking agent has a workability improving action (meaning an appearance improving action after processing, and in the examples described later, it is evaluated by the number of cracks in an adhesion bending test). Even if a rust inhibitor is added, excellent workability can be secured.

  Moreover, it became clear from the examination result of the present inventors that the melamine-based crosslinking agent has excellent corrosion resistance. Therefore, in the present invention, very good corrosion resistance can be obtained by using in combination with the above-described rust inhibitor.

  In the present invention, the isocyanate-based crosslinking agent and the melamine-based crosslinking agent may be used alone, but when both are used in combination, processability and corrosion resistance can be further improved. Specifically, it is recommended to contain a melamine resin at a ratio of 5 to 80 parts by mass with respect to 100 parts by mass of the isocyanate resin. When the melamine-based resin is less than 5 parts by mass, desired corrosion resistance cannot be obtained. On the other hand, when the melamine-based resin exceeds 80 parts by mass, the effect due to the addition of the isocyanate-based resin is not exhibited well, and the desired processability is achieved. Improvement effect cannot be obtained. More preferably, it is 10 mass parts or more and 40 mass parts or less with respect to 100 mass parts of isocyanate type resin, More preferably, they are 15 mass parts or more and 30 mass parts or less.

  In addition, the ratio of the resin, the rust inhibitor, the crosslinking agent, the black additive, and the conductive filler constituting the coating film forming component described above will be described in “Coating composition” described later.

  A coated body satisfying such a configuration is excellent in corrosion resistance, coating film adhesion and workability. Specifically, regarding the corrosion resistance, the area ratio of abnormal appearance parts (coating swelling, rust, etc.) in the salt spray test corrosion resistance test (72 hours) defined in JIS-Z-2371 is 10% or less (more preferably Satisfies 5% or less). The above properties are suitable for controlling the type of crosslinking agent used (for example, adding a predetermined amount of a melamine-based crosslinking agent useful for improving corrosion resistance alone) or suppressing the dissolution of a rust inhibitor. By adopting a structure such as a two-layer coating film on which a coating film (preferably a clear coating film) is applied, it is further enhanced. As a result, a more severe test [as defined in JIS-Z-2371] The area ratio of appearance abnormality in the salt spray test corrosion resistance test (120 hours)] satisfies 10% or less (more preferably 5% or less).

  Furthermore, the said coated body is excellent also in coating-film adhesiveness and workability. Here, both “coating adhesion” and “workability” have a common property in terms of “excellent appearance after processing”, but in the present invention, “workability” is particularly “ (The number of cracks in the adhesion bending test is 5 or less, more preferably 2 or less. On the other hand, “coating film adhesion” is evaluated by “coating film adhesion of the processed part”.

  The present invention coated body using a nonchromated metal plate has been described above.

  The coated body of the present invention described so far has a single-layer coating structure in which a coating film is applied to a substrate. However, the present invention further includes a multilayer coating in which one or more coating films are coated thereon. Configuration aspects are also encompassed. In particular, in the present invention, when a black coating is used particularly for the purpose of imparting scratch resistance and fingerprint resistance, it is recommended to have a two-layer coating configuration in which a clear coating is applied to the black coating. Since the black coating is painted in dark black, it has the demerit that fingerprints are easily noticeable when handled by hand, and the appearance quality deteriorates, but the clear film improves the fingerprint resistance. Is done. In addition, even if the black coating film has wrinkles, there is an advantage that the wrinkles become inconspicuous by applying the clear coating.

  Here, in order to improve the scratch resistance and fingerprint resistance while maintaining the desired characteristics (heat dissipation characteristics / self-cooling properties), it is important to control the film thickness of the clear coating film, When providing excellent conductivity in addition to heat dissipation, the preferred range of the clear coating thickness changes.

  That is, in the case of a coated body in which a conductive filler is not added to the coating film, in order to maintain the excellent heat dissipation property / self-cooling property and to improve the anti-scratch property and the fingerprint resistance, It is recommended to control the film thickness to 0.1 to 10 μm. If it is less than 0.1 μm, the effect of improving the scratch resistance and fingerprint resistance cannot be obtained. More preferably, it is 0.2 μm or more, and further preferably 0.3 μm or more. However, even if the film thickness is thicker than 10 μm, the effect of improving the scratch resistance and the like is saturated, and it is uneconomical because only the coating cost increases, so the upper limit is preferably 10 μm. More preferably, it is 8 micrometers or less, More preferably, it is 7 micrometers or less.

  By using a two-layer coating film structure in which a clear coating film is coated on a coating film as described above, the scratch resistance can be significantly improved compared to a single-layer coating film structure consisting of a coating film alone, The formation of a clear coating film is extremely effective in that an improvement in fingerprint resistance that cannot be achieved with a single-layer coating film structure can be obtained.

  Here, it does not specifically limit as resin which comprises the said clear membrane | film | coat, All resin which can form a transparent membrane | film | coat is included. Specific examples include resins such as acrylic resins, urethane resins, polyolefin resins, polyester resins, fluorine resins, and silicon resins, and mixtures or modified resins of these resins. Furthermore, additives such as a cross-linking agent, a wax, and a matting agent may be added to the clear film as long as the effects of the present invention are not impaired. Thereby, the lubricity and strength of the coating film can be easily adjusted, and as a result, the scratch resistance can be further enhanced. The additive used in the present invention is not particularly limited as long as it is usually used in a coating film and can effectively exhibit the above-described action. For example, a crosslinking agent such as a melamine crosslinking agent or a blocked isocyanate crosslinking agent. Is mentioned.

  As described above, the coated body of the present invention includes those having a plurality of coating structures coated with a coating film that is not a clear coating film. In this case, the resin constituting the above-described clear coating film and A pigment such as a color pigment can be further added to the additive.

  Further, as a coating composition applied to a substrate subjected to a chromium-free base treatment, 35% by mass of a polyester resin in which an epoxy-modified polyester resin and / or a phenol derivative is introduced into the skeleton with respect to a coating film forming component. Or more (preferably 40% by mass or more, more preferably 45% by mass or more), 2 to 25% by mass of a rust inhibitor (preferably 3% by mass or more, 20% by mass or less; still more preferably 4% by mass or more, 15% by mass or less), 1 to 20% by mass of the crosslinking agent (preferably 2% by mass or more and 18% by mass or less; even more preferably 3% by mass or more and 15% by mass or less), and 3% by mass of the black additive. Super-containing coating compositions are also included within the scope of the present invention. Among these, preferable requirements for the above-mentioned crosslinking agent (preferably containing a melamine-based crosslinking agent in a ratio of 5 to 80 parts by mass with respect to 100 parts by mass of the socyanate-based crosslinking agent), and preferable requirements for the black additive described above. That's right. By using the coating composition of the present invention, it is possible to form a chromium-free coating film excellent in heat dissipation, corrosion resistance, coating film adhesion, and processability. In particular, it can be suitably used as a paint for a chromium-free coated body.

  Next, a method for producing the coated body of the present invention will be described. The coated body of the present invention can be produced by applying a coating containing the above components to the surface of a substrate by a known coating method and drying it. Although the coating method is not particularly limited, for example, the surface of a long metal strip that has been cleaned and subjected to pre-coating treatment (for example, phosphate treatment, chromate treatment, etc.) as necessary, roll coater method, spray method, Examples thereof include a method in which a paint is applied using a curtain flow coater method and the like, and dried by passing through a hot air drying furnace. A roll coater method is preferable in practical use in consideration of uniformity of film thickness, processing cost, coating efficiency, and the like.

When a resin-coated metal plate is used as the substrate, a phosphate treatment or a chromate treatment may be performed as a pre-coating treatment for the purpose of improving the adhesion to the resin film or the corrosion resistance. However, with respect to the chromate treatment material, it is preferable to suppress the Cr adhesion amount during chromate treatment to 35 mg / m ² or less from the viewpoint of chromium elution during use of the resin coating. This is because it is possible to suppress chromium elution from the underlying chromate treatment layer within this range. In addition, the conventional chromate treatment material has a water-resistant adhesion property of the top coating provided as needed, and tends to decrease in a wet environment with the elution of hexavalent chromium, but the above metal plate suppresses the elution. For this reason, the water-resistant adhesion of the top coat does not deteriorate.

  Alternatively, a non-chromate-type coated body can be obtained by applying the above-described chromium-free ground treatment by a roll coater method, a spray method, an immersion treatment method, or the like.

  Further, according to the present invention, there is provided an electronic device component having a heating element built in a closed space, wherein the electronic device component is an electronic device in which all or a part of the outer wall is constituted by the above-described electronic device member coating body. Equipment parts are also included. The electronic device parts include information recording products such as CD, LD, DVD, CD-ROM, CD-RAM, PDP, LCD, etc .; electrical / electronic / communication related products such as personal computers, car navigation systems, car AVs; projectors, televisions, AV equipment such as video and game machines; copiers such as copiers and printers; power supply box covers such as air conditioner outdoor units, control box covers, vending machines, refrigerators and the like.

  The present invention will be described in further detail with reference to the following examples. However, the following examples are not intended to limit the present invention, and all modifications and implementations without departing from the spirit of the present invention are included in the present invention.

Example 1
In this example, the heat release property, self-cooling property, and conductivity of each specimen with various types of additives and the emissivities of the front and back surfaces were measured.

  First, an electrogalvanized steel sheet (thickness 0.6 mm) as a base plate, and a paint in which the additives shown in Table 1 below are added to the front and back surfaces (a polyester resin is used as a base resin and a melamine resin is used as a crosslinking agent) After coating, it was baked and dried to obtain No. Sample materials 1 to 19 (120 × 150 mm) were prepared. Of these, No. 17 uses a blackened Zn-Ni alloy-plated steel plate (plate thickness 0.6 mm) as the original plate, and the other electrogalvanized steel plate (plate thickness 0.6 mm) as the original plate. )It was used.

  About each specimen obtained in this way, using the apparatus of FIG. 1, based on the method described above, the integrated emissivity of infrared rays (wavelength: 4.5 to 15.4 μm), ΔT1, ΔT2, and conductivity Was measured.

In addition, ΔT1 representing heat dissipation characteristics was relatively evaluated according to the following criteria. In the second coated body according to the present invention, the coated bodies of ◎, ●, and ◯ are evaluated as “those that exhibit good heat dissipation in the coated body”.
A: 3.5 ≦ ΔT1
●: 2.7 ≦ ΔT1 <3.5
○: 1.5 ≦ ΔT1 <2.7
Δ: 1.0 ≦ ΔT1 <1.5
×: ΔT <1.0

Further, ΔT2 indicating self-cooling property was evaluated relative to the following criteria. It shows that it is excellent in the thermal radiation characteristic, so that (DELTA) T2 is large. In addition, in this invention, the coating body of (double-circle) and (circle) is evaluated as "the thing which exhibits the outstanding self-cooling property."
A: 1.5 ≦ ΔT2
○: 0.5 ≦ ΔT2 <1.5
×: ΔT2 <0.5

  The obtained results are shown in Tables 1 and 2.

  From the said table | surface, all the coating bodies (No. 1-12) which satisfy the requirements of this invention maintain the favorable heat dissipation characteristic, and also have the outstanding self-cooling property. In particular, in the formula (4) which is an index of the self-cooling property, the Q value (= 0.9a−b) is a No. far exceeding 0.045 or more. 1 to 8 exhibit extremely excellent self-cooling properties, and it can be seen that the larger the Q value, the better the self-cooling properties.

  Of these, Nos. 3 and 7 in Table 1 are examples in which the surface was coated with a carbon black-containing coating film and the back surface was coated only with a coating film (no additive); 6 / No. No. 12 is an example in which the surface / back surface is coated with a carbon black-containing coating film and the back surface / front surface is coated with a titanium oxide-containing coating film; No. 10 is an example in which the front and back surfaces are both coated with a metallic appearance coating film; 11 is an example in which an Al flake-containing coating film is coated on the front surface and a carbon black-containing coating film is coated on the back surface, both of which satisfy the requirements of the present invention and have excellent self-cooling properties. And has good heat dissipation characteristics.

  In Table 1, No. 1 and no. 11 is an example in which carbon black is added to the coating film on the back surface, but the index [Equations (4) and (5)] defined by the second coated body is satisfied even if the above equation (6) is not satisfied. Therefore, both self-cooling properties and heat dissipation properties are good.

  On the other hand, all the coated bodies (Nos. 13 to 19) that do not satisfy the requirements of the present invention are inferior in self-cooling properties.

  For example, no. Reference numeral 13 denotes a single-sided coated body in which coating is not performed on one side, and a heat dissipation characteristic as a base is not obtained. Similarly, no. No. 14, since the composition of the surface (carbon black-containing coating film) does not satisfy the above formula (6), the formula (5) serving as an index of the heat dissipation characteristics is not satisfied, and the desired heat dissipation characteristics cannot be obtained. No. No. 15 does not add any additive to the front and back surfaces, and the coating thickness is thin, so the desired heat dissipation characteristics cannot be obtained.

  On the other hand, no. No. 16 is an example in which the emissivities of the front and back surfaces are similar, and a desired self-cooling property cannot be obtained. No. No. 17 is a conventional example in which the front and back surfaces are blackened by the same method, and the emissivity of the front and back surfaces is approximately the same, so that a desired self-cooling property cannot be obtained. No. No. 18 is an example in which the emissivity of the back surface is larger than that of the front surface, and the self-cooling property is lowered.

In this invention painted body, it is the schematic of the apparatus used in order to evaluate (DELTA) T1 (heat dissipation). It is a graph which shows the range excellent in both the self-cooling property and the thermal radiation characteristic in the coating body of this invention. In Example 1, it is a graph which shows the relationship between (DELTA) T2 and Q value (= 0.9a-b). In Example 1, it is a graph which shows the relationship between (DELTA) T1 and R value [= (a-0.05) * (b-0.05)].

Explanation of symbols

1 Test material (subject)
2 Insulation 3 Heating element 4 Protective member (cover)
5 Temperature measuring device

Claims (20)

A coated body in which a coating film is coated on the front and back surfaces of the substrate, and at least the surface of the substrate is a heat radiation coating film having a heat dissipation property and a heat radiation coating film not containing a conductive filler,
The integral emissivity of infrared rays (wavelength: 4.5 to 15.4 μm) when the coated body is heated to 100 ° C. satisfies the following expressions (4) and (5) (provided that a × b ≧ 0. 42), a coated body for electronic device members having excellent heat dissipation and self-cooling properties.
b ≦ 0.9 (a−0.05) (4)
(A−0.05) × (b−0.05) ≧ 0.08 (5)
a: Infrared integrated emissivity of a coated body with a heat dissipation coating coated on the surface
b: Infrared integrated emissivity of a coated body having a heat radiation coating coated on the back surface   2. The coated body according to claim 1, wherein the heat radiation coating film contains at least 50 to 70 mass% of titanium oxide as a heat radiation additive and satisfies a film thickness of 25 to 30 μm. A coated body in which a coating film is coated on the front and back surfaces of the substrate, and at least the surface of the substrate is a heat radiation coating film having a heat dissipation property and a heat radiation coating film not containing a conductive filler,
The heat dissipation coating contains a black heat dissipation additive, and
The coating body for electronic device members excellent in heat dissipation and self-cooling characteristics characterized by satisfying the following formula (6).
(X-3) × (Y−0.5) ≧ 3 (6)
In formula, X is content (mass%) of the black heat dissipation additive contained in a heat dissipation coating film,
Y means the thickness of the heat radiation coating film (μm). Furthermore, the coating body of Claim 3 which satisfies the following Formula (7).
4 ≦ X <15 (7)
In formula, X means content (mass%) of the black heat-radiating additive contained in a heat-radiation coating film.   Furthermore, the coating body of Claim 3 or 4 which satisfies the thermal radiation coating film thickness Y> 1 micrometer.   The coated body according to any one of claims 3 to 5, wherein the black heat-dissipating additive has an average particle diameter of 5 to 100 nm.   The coated body according to claim 3, wherein the black heat dissipating additive is carbon black.   The coated body according to any one of claims 1 to 7, wherein the resin forming the heat radiation coating film is a non-hydrophilic resin.   The coated body according to claim 8, wherein the non-hydrophilic resin is a polyester resin.   The coated body according to any one of claims 1 to 9, wherein the heat-dissipating coating film is coated with a clear coating film so that wrinkle resistance and fingerprint resistance are enhanced.   The coated body according to any one of claims 1 to 10, wherein the base is a metal plate subjected to a chromium-free ground treatment, and the heat radiation coating further contains a rust preventive.   The coated body according to any one of claims 1 to 11, which is used as a casing for electronic device parts.   It is a coating composition used for the coating body in any one of Claims 1-12, Comprising: With respect to a coating-film formation component, it contains more than 3 mass% of black additives, and does not contain a conductive filler. A coating composition for electronic equipment parts.   The composition according to claim 13, wherein the black heat-dissipating additive has an average particle size of 5 to 100 nm.   The composition according to claim 13 or 14, wherein the black heat dissipating additive is carbon black. It is a coating composition used for the coating object according to claim 11,
35% by mass or more of a polyester resin in which an epoxy-modified polyester resin and / or a phenol derivative is introduced into the skeleton, 2 to 25% by mass of a rust preventive agent, and 1 to 20% by mass of a crosslinking agent with respect to a coating film forming component. And a black additive containing more than 3% by mass, and containing no conductive filler.   The composition according to claim 16, wherein the crosslinking agent contains a melamine resin at a ratio of 5 to 80 parts by mass with respect to 100 parts by mass of the isocyanate resin.   The composition according to claim 16 or 17, wherein the black additive has an average particle size of 5 to 100 nm.   The composition according to claim 16, wherein the black additive is carbon black. An electronic device part containing a heating element in a closed space,
12. The electronic device part according to claim 1, wherein the entire or part of the outer wall of the electronic device part is constituted by the coating body for an electronic device member according to any one of claims 1 to 11.

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