KR20110111526A - Resin-coated metallic material with excellent planar-direction thermal conductivity - Google Patents

Abstract

A resin-coated metal material coated with a resin film containing thermally conductive particles on at least one surface of a metal substrate, wherein the thermally conductive particles observed in the measurement field of view when the scanning electron micrograph of the planar cross section of the resin film is image analyzed. It is a resin coating metal material which satisfy | fills the requirements of 1)-(3).
(1) the average value of the flatness ratio expressed by the maximum length of the thermally conductive particles divided by the minimum length (maximum length / minimum length) is 3.0 or more, and (2) the inclination angle of the maximum length of the thermally conductive particles with the horizontal line in the plane direction. When it measured, the frequency ratio of the thermally conductive particle which exists in the range of 0 degrees or more and less than 30 degrees of inclination angles is 40% or more, and (3) the area ratio of thermally conductive particles is 30% or more.

Description

RESIN-COATED METALLIC MATERIAL WITH EXCELLENT PLANAR-DIRECTION THERMAL CONDUCTIVITY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal material having excellent surface thermal conductivity, and particularly, to an electronic device component (electrical device component or optical) in which a heat source is in local contact with the metal material, and high thermal conductivity in the surface direction is strongly required. It relates to a resin coating metal material which is suitably used as a raw material of (including equipment parts). Examples of such electronic device components include a heat sink, a back chassis such as a thin television, a metal housing (casing) containing an electronic device component incorporating a heat source, and the like.

As the performance and miniaturization of electronic devices and the like become more and more advanced, studies on heat radiation members for radiating heat generated from heat sources inside electronic devices are being actively conducted. Among these, in the heat radiating member which the heat source locally contacts, such as the back chassis of a thin television, it is calculated | required to diffuse the heat | fever which generate | occur | produced quickly in large area, ie, the thermal conductivity in the surface direction of a heat radiating member is excellent. This is because when the surface direction thermal conductivity is low, a temperature gradient occurs in the surface direction, causing dispersion in in-plane temperature, and defects such as color unevenness of the light emitting surface and cracking of the glass substrate occur.

In particular, when the heat dissipation member is made of a metal material such as steel sheet, and the heat source is in contact with the metal material, it is very important to increase the surface direction heat conductivity instead of the thickness direction thermal conductivity of the metal material. When the heat source is in contact with a heat dissipating member such as a steel sheet, two paths of heat transfer from the heat source to the steel sheet and further to the outside are considered, but in the metal material having a thin plate thickness like the steel sheet, the thickness direction Because the heat transfer distance is short, the heat transfer increase effect by the increase in the thickness direction thermal conductivity is very small, while the heat transfer area in the plane direction is very large, it is expected that a significant increase in the heat transfer amount by the improvement in the plane direction thermal conductivity. .

However, most of the studies on the heat dissipation member focus on improving the thermal conductivity in the thickness direction of the heat dissipation member from the viewpoint of rapidly dissipating heat from the electronic device components containing the heat source to the outside. The thermal conductivity of is not very mindful. For example, Patent Document 1 discloses a metal material having a coating layer containing fine carbon fibers (typically carbon nanotubes) having an average aspect ratio of 3 or more as a material capable of efficiently absorbing and dissipating heat. Taking into account the measuring method of, it is considered that only the thermal conductivity in the thickness direction is evaluated.

Japanese Patent Laid-Open No. 2005-199666

This invention is made | formed in view of the said situation, The objective is to provide the resin coating metal material excellent in surface direction thermal conductivity.

The resin coating metal material of this invention is a resin coating metal material in which the resin film containing heat conductive particle was coat | covered on at least one surface of a metal base material, and when it carries out image analysis of the scanning electron microscope photograph of the surface direction cross section of a resin film, The observed thermally conductive particles satisfy the following requirements (1) to (3):

(1) The average value of the flatness ratio expressed by the maximum length of the thermally conductive particles divided by the minimum length (maximum length / minimum length) is 3.0 or more,

(2) When the inclination angle at which the maximum length of the thermally conductive particles forms the horizontal line in the plane direction is measured, the frequency ratio of the thermally conductive particles existing in the range of 0 ° or more and less than 30 ° is 40% or more.

(3) The area ratio of the thermally conductive particles is 30% or more.

In a preferred embodiment of the present invention, the in-plane thermal conductivity of the resin film is 1.5 W / mK or more.

In a preferred embodiment of the present invention, the thermally conductive particles are copper, aluminum or graphite.

In preferable embodiment of this invention, the said resin coating metal material is used for an electronic device component.

In this invention, the electronic device component which has the said resin coating metal material is also included in the scope of the present invention.

Since this invention is comprised as mentioned above, the resin coating metal material with high thermal conductivity in a surface direction was provided. When the metal material of the present invention is used, it is possible to prevent a decrease in the temperature gradient caused by the heat source in contact with the metal material, and therefore, a back chassis such as a heat sink or a thin television, in which high thermal conductivity in the surface direction is strongly required. It is used suitably as a raw material of an electronic device component.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the thermally conductive particle in a resin film.
2 is No. 1 of Example 1; It is the inclination-angle frequency distribution graph of 9 (example of this invention).
3 is No. of Example 1; It is a photograph which shows the SEM image of 9 (example of this invention), and an image analysis result.
4 is No. of Example 1; It is a photograph which shows the SEM image of 11 (comparative example), and an image analysis result.
5 is No. of Example 1; It is a photograph which shows the SEM image and the image analysis result of 14 and 16 (example of this invention).
6A is No. 1 of Example 1; It is a photograph which shows the SEM image of 2-5 (comparative example), and an image analysis result.
6B is No. 1 of Example 1; It is a photograph which shows the SEM image of 6-8 (comparative example), and an image analysis result.
7 is a schematic view for explaining a configuration of an in-plane thermal conductivity measurement apparatus used in the present invention.
8 is No. of Example 1; It is the inclination-angle frequency distribution graph of 9, 14, 16 (example of this invention).
9A is No. 1 of Example 1; It is the inclination-angle frequency distribution graph of 2-6 (comparative example).
9B is No. 1 of Example 1; It is a tilt angle distribution graph of 7, 8, and 11 (comparative example).
10A is No. 1 of Example 1; It is a photograph which shows the SEM image of 9, 10, 12, 15 (example of this invention), and an image analysis apparatus.
10B is No. 1 of Example 1; It is a photograph which shows the SEM image and image analysis apparatus of 17, 19, 20 (example of this invention).
11 is No. 1 of Example 1; It is a photograph showing the SEM image of 18 (comparative example) and an image analysis apparatus.
12A is No. 1 of Example 1; It is the inclination-angle frequency distribution graph of 9, 10, 12 (example of this invention).
12B is No. 1 of Example 1; It is the inclination-angle frequency distribution graph of 15 and 17 (example of this invention).
12C is No. 1 of Example 1; It is the inclination-angle frequency distribution graph of 19 and 20 (example of this invention).
13 is a view of No. 1 of Example 1; It is an inclination-angle frequency distribution graph of 18 (comparative example).

MEANS TO SOLVE THE PROBLEM The present inventors examined in order to provide the resin coating metal material suitably used as a raw material of the heat dissipation member among heat dissipation members for electronic devices, especially since a heat source locally contacts a heat dissipation member, and high thermal conductivity in surface direction is strongly required. Has been repeated. As a result, the desired high in-plane thermal conductivity is not obtained by simply adding a large amount of high thermal conductivity particles having high thermal conductivity in the resin film (see, for example, Nos. 3 and 4 in Table 2). The present invention was completed by discovering that the shape and the direction (degree of tilt of the particle with respect to the horizontal line in the plane direction and defined as "inclined angle") are obtained at a predetermined area ratio in the resin film.

That is, the resin coating metal material of this invention is resin by which the resin film containing heat conductive particle was coat | covered on at least one surface (heat source side) of a metal base material, and a scanning electron micrograph (SEM photograph) of the surface direction cross section of a resin film is carried out. When image analysis, the thermally conductive particles observed in the measurement field of view satisfy the following requirements (1) to (3):

(1) The average value of the flatness ratio expressed by the maximum length of the thermally conductive particles divided by the minimum length (maximum length / minimum length) is 3.0 or more,

(2) When the inclination angle at which the maximum length of the thermally conductive particles forms the horizontal line in the plane direction is measured, the frequency ratio of the thermally conductive particles existing in the range of 0 ° or more and less than 30 ° is 40% or more,

(3) The area ratio of the thermally conductive particles is 30% or more.

Thus, the characteristic part of this invention is having prescribed | regulated the requirements of said (1)-(3) as a requirement which contributes greatly to the improvement of surface direction thermal conductivity. As demonstrated in the examples which will be described later, it is necessary in the present invention to satisfy all three requirements, and it is not possible to obtain desired characteristics that any one requirement does not satisfy the present invention.

First, the flatness ratio prescribed | regulated by said (1) and the inclination-angle prescribed | regulated by said (2) are demonstrated in detail, referring FIG. FIG. 1: is a figure which shows typically the heat conductive particle obtained by the image analysis means demonstrated in detail later.

The flatness ratio prescribed | regulated by said (1) is computed by the ratio (maximum length / minimum length) of the maximum length shown in FIG. 1, and the minimum length computed based on this maximum length. The minimum length is taken as the length when the width of the parallel lines becomes minimum when the heat conductive particles are sandwiched by two straight lines parallel to the maximum length. In the present invention, the value obtained by dividing the maximum length by the minimum length is defined as "flat rate of the thermally conductive particles".

The inclination angle (direction) prescribed | regulated by said (2) is made into the angle formed by the horizontal line of the surface direction, and the line which crosses a horizontal line with the maximum length extended as shown in FIG. Here, the angle formed with the horizontal line in the plane direction means an angle with respect to the direction parallel to the surface of the resin film in a plane perpendicular to the surface of the resin film. Next, according to the analysis procedure mentioned later, the number (frequency) of thermally conductive particles which exist in the range of inclination angle 0-180 degrees is measured every 10 degrees, and a gradient angle frequency distribution graph is created. For reference, No. 1 of Table 1 of the Example mentioned later. The inclination-angle frequency distribution graph of 9 is shown in the top view of FIG. The inclination angles (10 °, 20 °, up to 180 °) are plotted on the horizontal axis of FIG. 2, and the number of thermally conductive particles present in 0 ° or more and less than 10 °, 10 ° or more and less than 20 ° and the like for each inclination angle. Is indicated by a bar graph. In the present invention, the results of the angle of inclination of 0 ° or more and less than 10 ° and of more than 170 ° and 180 ° or less are considered equivalent because they are in enantiomer relations, that is, the frequency of the thermally conductive particles within each inclination angle range is determined. Add up. In dividing the entire inclination angle range (0 to 180 °) by 10 °, as shown in the above example, it is referred to as "more than or less" from 0 ° to 90 °, and from "more than 90 ° to 180 ° or less", Hereinafter. On the other hand, only 90 degrees were made into the area of "80 degrees or more and less than 90 degrees" or "more than 90 degrees and 100 degrees or less." Thereby, the frequency of all the particles which exist in the range of 0 to 180 degrees of inclination angle can be shown as the frequency of the particle which exists in the range of 0 to 90 degrees of inclination angle.

The lower view of FIG. 2 summarizes the inclination-angle frequency distribution graph (tilt angle 0-180 degrees) shown in the upper view of FIG. 2 as mentioned above, and shows the frequency of the heat conductive particle which exists in the range of inclination angle 0-90 degrees. It is shown in °. In the present invention, based on the inclination-angle frequency distribution graph of the lower view of FIG. 2 thus obtained, the total of the frequencies existing within the range of the inclination angle of 0 to 30 ° is the total of all the frequencies existing within the range of the inclination angle of 0 to 90 ° (total frequency). The value divided by) is defined as "the frequency ratio of the heat conductive particles which exist in the range of 0 to 30 degrees of inclination angle".

Next, the usefulness of the present invention will be described in detail with reference to FIGS. 3 and 4. Among these, FIG. 3 is No. 1 of Example 1 which satisfies all the requirements of said (1)-(3). It is a photograph which shows the SEM image of 9 (invention example) and the image analysis result, and FIG. 4 is No. 1 of Example 1 which does not satisfy the requirement of said (3). It is photograph of 11 (comparative example).

As shown in FIG. 3, in the example of this invention, the particle | grains which have a predetermined flat shape, and exist in large numbers existed while the particle | grains of predetermined inclination-angle are substantially continuous and overlapping suitably toward a surface direction. As a result, it is considered that heat passages (paths) are formed toward the surface direction and the surface thermal conductivity is high. For reference, in the image analysis result of FIG. 3, the direction of heat flow is indicated by →.

On the other hand, in the comparative example, as shown in FIG. 4, there exist several cavity places in which particle | grains do not exist over the surface direction. Therefore, it is considered that the heat passage in the plane direction is divided to lower the plane thermal conductivity.

For reference, the results of Example 1 other than the above are shown in FIGS. 5, 6A, 6B, 10A to 10C, and FIG. 11. 5, 10A and 10B show No. 1 of the first embodiment that satisfies all the requirements of (1) to (3) above. 9, 10, 12, 14, 15, 16, 17, 19, 20 (all examples of the present invention) are photographs showing SEM images and image analysis results, and thermal paths useful for improving the in-plane thermal conductivity as in FIG. It can be seen that is formed. 6A, 6B, and 11 show No. 1 not satisfying any of the above requirements (1) to (3). It is a photograph of 2-8 and 18 (all comparative examples). 6A, 6B and 11, similar to FIG. 4 described above, it can be seen that a heat path useful for improving the in-plane thermal conductivity is blocked.

The resin-coated metal material which satisfies all of the requirements of (1) to (3) above has a surface direction thermal conductivity of 1.5 W / mK or more (preferably 1.55 W / mK or more, more preferably 1.6 W / mK or more), More preferably 1.65 W / mK or more, even more preferably 1.7 W / mK or more). According to this invention, as shown in the Example mentioned later, what was very high in the surface direction thermal conductivity of a resin film is 2.0 W / mK or more, Furthermore, 2.5 W / mK or more was obtained.

Here, the surface direction thermal conductivity is "photoelectric method thermal constant measuring apparatus PIT-R1 type" made by an exclusive measuring device (Shinku-Riko. Inc. (currently Alvac Co., Ltd. (ULVAC-RIKO. Inc.)). ] Is calculated based on the following formula (1) based on the thermal diffusivity obtained using]. This device is particularly useful as a device for measuring the planar thermal diffusivity of thin samples having a thickness of 0.3 mm or less.

Planar thermal conductivity (W / mK) = thermal diffusivity (× 10 ^-6 × m ² / sec) × specific heat (J / gK) × density (g / cm ³ )

The thermal diffusivity measuring method in the above formula (1) will be described with reference to FIG. 7. It is a schematic diagram explaining the structure of the said measuring apparatus used for this invention. As shown in FIG. 7, the said measuring apparatus irradiates the light of an alternating current waveform to the sample plate (production method mentioned later) set in the apparatus, and moves a shutter to the plate surface direction of a sample, shielding light, and shielding the plate surface of a sample. Based on the following expression (2) from the gradient d of the absolute value (ln | Tac |) of the absolute value of the alternating temperature Tac measured by the moving distance L of the direction and the thermocouple attached to the surface on the opposite side to the surface to which light is irradiated Calculate the thermal diffusion rate D. In the following examples, the measurement environment was room temperature in the air, and the measurement frequency (f in the following formula (2)) was set to 0.1 Hz.

Thermal diffusion rate D (m ² / sec) = π × f (Hz) / d ² (m ^-2 )

The manufacturing method of the sample plate set to the said measuring apparatus is as follows.

First, a resin film sample for measuring the thermal diffusion rate (in a later example, a resin-coated polyimide film cut to about 5 mm in width and about 10 mm in length) is prepared. The size of the sample to be cut may be about 5 mm in width, and the length may be slightly longer than 10 mm.

Next, as shown in FIG. 7, the light receiving surface of the said sample is blackened. Specifically, using the attached carbon spray (not shown), the carbon spray is blown out so that the surface becomes evenly black from a place about 30 cm away from the sample to blacken the sample. In addition, a sample plate with a thermocouple is attached on the side opposite to the light receiving surface of the sample. Specifically, as shown in FIG. 7, only a minimum amount of silver paste is applied to the intersection of the thermocouple sample plate and the sample plate to bond the sample and the thermocouple. In that case, when the resin film is thin, the warpage of a sample may be seen, but in that case, a sample may be cut long and fixed to a thermocouple sample plate.

In this way, since the light receiving surface is blackened and the sample plate with a thermocouple sample plate attached to the opposite side to a light receiving surface is obtained, this sample plate is set to the said measuring apparatus.

In addition, the specific heat of the resin film sample in said Formula (1) was measured at room temperature using differential scanning calorimetry (Seiko Instruments Inc. make DSC220C). Further, in order to accurately measure the density [weight / (length × width × thickness)] of the resin film sample in the above formula (1), the size (mm) of the length and the width is measured accurately using a nogis, and the flatness ratio is measured. The film thickness (micrometer) was calculated | required from the SEM cross-sectional photograph used for the measurement of.

The thermal diffusivity, specific heat and density obtained in this way were substituted into the above formula (1) to calculate the in-plane thermal conductivity.

Next, the measurement procedure of said (1)-(3) is demonstrated in detail.

First, it cuts into the surface parallel to the resin film of a resin coating metal material, and exposes the surface direction cross section of a resin film. SEM cross-sectional photographs are taken of this resin film surface direction cross section using a scanning electron microscope (SUPRA35 by Carl Zeiss). Observation magnification was set to 1500 times, and the reflecting electron image of SEM in the observation area | region of 600 micrometers x 800 micrometers per one image was image | photographed, and 20 points in total were observed (n number = 20). The taken SEM photograph was processed with the image analyzer (made by Nireco, LUZEX AP 2006.11 edition), and the maximum length, minimum length, and average area ratio were calculated | required. On the other hand, depending on the type of additives such as thermally conductive particles contained in the resin film, the SEM image may be unclear. In that case, a SEM photograph is printed, a PET film is attached thereon, and the portion of the additive is black magic. The traced image can be used for image analysis.

Regarding said (1), in this invention, the average value of the flatness rate of a thermally conductive particle is so good that it is good, Preferably it is 3.2 or more, More preferably, it is 3.5 or more. On the other hand, the upper limit of the average value of the flatness ratio is not particularly limited from the viewpoint of in-plane thermal conductivity, but in consideration of applicability and the like, it is preferably about 20.0, more preferably 19.0.

In addition, with respect to said (2), in this invention, the frequency ratio of the heat conductive particle which exists in the range of 0 degrees or more and less than 30 degrees of inclinations is so good that it is good, Preferably it is 42% or more, More preferably, it is 45% or more. .

In addition, with respect to said (3), in this invention, the area ratio of heat conductive particle is so good that it is good, Preferably it is 32% or more, More preferably, it is 35% or more. On the other hand, the upper limit of the area ratio is not particularly limited from the viewpoint of surface direction thermal conductivity, but in consideration of workability, corrosion resistance, and the like, is preferably about 60%, more preferably 55%.

In the above, the requirements of said (1)-(3) which characterized this invention were demonstrated.

The heat conductive particle used for this invention is not specifically limited, What is normally used for a heat radiating member etc. can be used. Specifically, those having a high thermal conductivity having a thermal conductivity of about 30 W / mK or more are preferably used, and typically copper, aluminum, graphite, Al ₂ O ₃ , SiC, and the like. These are known as having high thermal conductivity in themselves, but as demonstrated in later examples, the surface direction thermal conductivity when added to the resin film can be kept high by appropriately controlling their shapes, inclination angles, and the like.

The preferable average particle diameter of the said heat conductive particle is about 1-40 micrometers, More preferably, it is 1.5-35 micrometers. The average particle diameter can be measured by, for example, a laser diffraction scattering method (micro-track method). When using a commercial item like the Example mentioned later, you may refer to the average particle diameter provided by a manufacturer. In detail, it is preferable to control the average particle diameter of the said heat conductive particle suitably in relationship with the thickness of a resin film. This is because if the average particle diameter of the thermally conductive particles is too large with respect to the thickness of the resin film, the inclination angle deviation of the thermally conductive particles in the resin film may become large and the requirements of the above (2) may not be satisfied. Specifically, the average particle diameter of the thermally conductive particles is preferably controlled within a range of approximately 0.1 to 5 times the thickness of the resin film.

As the heat conductive particles used in the present invention, commercially available products may be used. Specifically, for example, copper, such as 1200YP manufactured by Mitsui Mining & Smelting Co., Ltd .; Aluminum such as MH-8802, MC-606, ME-12, M-701, GX-2134, and BS-200 manufactured by Asahi Kasei Chemicals Corporation; Graphite, such as SP-20 by Nippon Graphite Industry Co., Ltd., SRP-7 by Ito Kokuen Co., Ltd., CNP15, etc. are illustrated.

The shape of the metal material used for this invention is not specifically limited, Although a metal plate is typically mentioned, other tube materials, wire rods, rod materials, mold release materials, etc. can also be used. Moreover, the kind of metal material is not specifically limited, either, Usually used for the housing | casing of electronic device components, etc. can be used. As a metal plate, a steel plate is mentioned typically, and a cold rolled sheet steel, a hot rolled sheet steel, a stainless steel plate, etc. are illustrated. Further, various plated steel sheets such as Al-based galvanized steel sheets such as electro-galvanized steel sheets (EG), hot-dip galvanized steel sheets (GI), alloyed hot-dip galvanized steel sheets (GA), and Al-Zn plated steel sheets, and Cu-based galvanized steel sheets; Steel sheet subjected to surface treatment such as chromate treatment or phosphate treatment; You may use the steel plate to which the non-chromate process was given. Alternatively, non-ferrous metal sheets can also be applied.

The resin film containing the thermally conductive particles may be formed on at least one surface (heat source side) of the metal material, whereby heat from the heat source can be rapidly diffused and transferred in the plane direction of the metal material. The resin film may be provided not only on one side but also on both sides.

Resin (base resin) which comprises the resin film used for this invention is not specifically limited, It is preferable to select suitable resin mainly according to the use of a metal material. As described above, the characteristic part of the present invention lies in specifying the requirements of the thermally conductive particles useful for improving the in-plane thermal conductivity, and the other requirements are not particularly limited as long as the operation of the present invention is not impaired. When the metal material of this invention is used suitably for the housing | casing of an electronic device component, and favorable workability is also required, it is preferable to use polyester-type resin or epoxy resin, those blends, or modified resin. Of course, it is not limited to this, and various resins useful for improving workability can be appropriately selected and used. Moreover, when corrosion resistance etc. are also required, resin suitable for corrosion resistance improvement can be selected and used. The modification of resin used for this invention can be suitably performed by a person skilled in the art according to the use of a metal material.

In addition to the said heat conductive particle and resin, the said resin film may add the addition component normally added to a resin film. As said addition component, an antirust pigment, an antistatic agent, a weather resistance improving agent, etc. are illustrated, for example, and can be added in the range which does not impair the effect | action of this invention. Or a known heat dissipating additive (typically oxides such as Co, Ni, Cu, Mn, Ag, Sn, sulfides, carbides, and the like, TiO ₂ , ceramics, iron oxides, and oxides, for the purpose of improving heat dissipation). Aluminum, barium sulfate, silicon oxide, etc.) may be added.

Moreover, you may have another film on the said resin film, and such a metal material is also included in the scope of the present invention. For example, a known clear film may be coated on the resin film for the purpose of improving scratch resistance and fingerprint resistance.

The resin coating metal material of this invention can be manufactured by apply | coating to the surface of a metal material by the well-known coating method, drying, or heat-baking the said base resin, heat conductive particle, and the coating material which melt | dissolved or disperse | distributed the other additive in a solvent as needed. Can be. Although a coating method is not specifically limited, For example, the roll coater method, the spray method, and the curtain flow coater are made to the surface of the base material which cleaned the surface and performed the coating pretreatment (for example, phosphate treatment, chromate treatment, etc.) as needed. Coating method using a flow flow coater method or the like, and drying by passing through a hot air drying furnace, or firing or baking.

The content of the thermally conductive particles contained in the paint varies depending on the kind of the particles, the resin used in combination, the kind of the solvent, and the like, and it is difficult to uniquely determine them, but it is about 10 to 70 to about 100 parts by mass of the paint. It is preferable that it is a mass part, More preferably, it is about 15-65 mass parts. Similarly, the content of the base resin contained in the paint varies depending on the kind of the resin and the kind of the thermally conductive particles and the solvent used in combination, and it is difficult to determine uniquely, but it is about about 100 parts by mass of the paint. It is preferable that it is 5-35 mass parts, More preferably, it is about 7-33 mass parts.

[Example]

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited by the following example, It is also possible to implement by making a change in the range which may be suitable for the meaning of the previous and later, However, it is included in the technical scope of this invention.

Example 1

(I) Preparation of Paint

Thermally conductive particles of symbols A to D shown below; Mixed solvent of xylene and cyclohexanone (xylene: cyclohexanone = 1: 1); And polyester-based resin (organic solvent-soluble polyester resin `` VYLON (trademark) 650 '' made by TOYOBO Co., Ltd.) and melamine resin (Sumitomo Chemical Co., Ltd.) Ltd.) "Similar (SUMIMAL, registered trademark) M-40ST", 80% of solids, a base resin (matrix resin) mixed in a mass ratio (drying ratio) 100: 20 at a ratio shown in Table 1, The paint was prepared by stirring vigorously with a hand homogenizer (No. 2-20 of Table 1). For reference, Table 1 also shows the average particle diameter (manufacturer display) of symbols A to D. In addition, it was also prepared to include only the base resin without adding the thermally conductive particles for comparison (No. 1 in Table 1).

Symbol A: Spherical copper powder (1300Y made from Mitsui metal mine)

Symbol B1: Uneven copper powder (Mitsui metal mine MA-C08J)

Symbol B2: Uneven copper powder (Mitsui metal mine MA-C04J)

Symbol C1: Flat copper powder (1100 YP made by Mitsui Metals Mine)

Symbol C2: Flat copper powder (1400 YP made by Mitsui Metals Mine)

Symbol C3: Flat copper powder (1300 YP made by Mitsui Metals Mine)

Symbol C4: (2L3N manufactured by Fukuda Metal Foil Industry)

Symbol D: Flat aluminum powder (GX-40A made by Asahi Chemical Co., Ltd.)

(II) Measurement of requirements (1) to (3) specified in the present invention

The flatness ratio of the thermally conductive particles of the requirement (1) defined in the present invention, the ratio of the frequency of the thermally conductive particles existing within the range of 0 ° or more and less than 30 ° of the inclination angle of the requirement (2), and the area ratio of the thermally conductive particles of the requirement (3). Was measured as follows.

First, an electrogalvanized steel sheet (plate thickness 0.8 mm, Zn adhesion amount 20 g / m <^2> ) was prepared as a raw plate. Each coating material prepared as described above was applied to the original plate by a bar coater, baked for 2 minutes at the highest achieved temperature (PMT) of 220 ° C., and then dried to obtain a resin coated metal plate having a resin film having a thickness of 10 to 20 μm. Got it.

According to the measurement procedure mentioned above, the said requirements (1)-(3) which were prescribed | regulated by this invention were measured about what cut | disconnected to the surface parallel to the resin film of the resin coating metal plate obtained in this way, and cut | disconnected about 15 mm x 25 mm. .

(III) Measurement of Planar Thermal Conductivity

As a base material used for the preparation of the resin film sample for thermal diffusivity measurement, the Teflon (TEFLON (trademark)) treated polyimide film ("Capton 500F" by Toray Dupont, 125 micrometers in thickness) was prepared. Each coating material was apply | coated to this original board similarly to said (II), and the resin coating polyimide film which has a resin film with a thickness of 10-20 micrometers was obtained. The surface direction thermal conductivity was measured by the method mentioned above using the measurement sample cut | disconnected from about 5 mm in width x about 10 mm in length from this resin film. The resin film sample used for the measurement was peeled off from the polyimide film, and was used. In the present Example, the thing whose surface direction thermal conductivity is 1.5 W / mK or more is set to pass ((circle)).

These results are put together in Table 2 and described.

For reference, no. 9, 10, 12, 14, 15, 16, 17, 19, 20 (example of the present invention), and No. The inclination-angle frequency distribution graph (inclined angle 0-90 degrees) of 2-8, 11, and 18 (comparative example) is shown to FIG. 8, 9A, 9B, 12A-12C, and FIG. 13, respectively. No. in FIG. The graph of 9 is the same as the bottom view of FIG. 2 described above.

From Table 2, it can consider as follows. First, the thermally conductive particles in the resin film satisfy all the requirements of (1) to (3) specified in the present invention. 9, 10, 12-17, 19, and 20 are No. which do not add a thermally conductive particle. Compared with 1, the in-plane thermal conductivity was obtained.

On the contrary, despite the addition of the same thermally conductive particles as described above, the following examples which do not satisfy any of the requirements defined in the present invention have not obtained desired characteristics. Specifically, No. 2 that does not satisfy the flatness ratio of the above (1). 4; No. which does not satisfy the flatness ratio of said (1) and the frequency ratio of said (2). 3; No. which does not satisfy the flatness ratio of said (1) and the area ratio of said (3). 2, 5, 7; No. that does not satisfy all the requirements of (1) to (3) above. 6; No. which does not satisfy the area ratio of said (3). As for 8, 10, and 18, the high in-plane thermal conductivity was not obtained.

Claims (5)

A resin coated metal material coated with a resin film containing thermally conductive particles on at least one side of a metal substrate,
When the image analysis of the scanning electron micrograph of the surface direction cross section of the said resin film, the thermally conductive particle observed in the measurement visual field satisfies the requirements of following (1)-(3), It is excellent in surface direction thermal conductivity. Resin Painted Metal Material:
(1) The average value of the flatness ratio expressed by the maximum length of the thermally conductive particles divided by the minimum length (maximum length / minimum length) is 3.0 or more,
(2) When the inclination angle at which the maximum length of the thermally conductive particles forms the horizontal line in the plane direction is measured, the frequency ratio of the thermally conductive particles existing in the range of 0 ° or more and less than 30 ° is 40% or more.
(3) The area ratio of the thermally conductive particles is 30% or more. The method of claim 1,
The resin coating metal material whose surface direction thermal conductivity of the said resin film is 1.5 W / mK or more. The method according to claim 1 or 2,
The said heat conductive particle is a resin coating metal material which is copper, aluminum, or graphite. The method according to claim 1 or 2,
Resin-painted metal used for electronic device parts. The electronic device component which has the resin coating metal material of Claim 4.

Images