TWI430881B - Metal material coated with excellent thermal conductivity resin in the surface direction - Google Patents

Description

Metal material coated with excellent thermal conductivity resin in the surface direction

The present invention relates to a metal material coated with an excellent thermal conductive resin in a surface direction, in particular, a partial contact of the metal material with respect to a heat source, and is suitable as an electronic machine part (including an electric machine part or an optical machine) which strongly requires high thermal conductivity in a plane direction. The raw material of the part) is a resin-coated metal material. Examples of such an electronic device component include a heat sink, a back chassis such as a thin television, and a metal case (housing) that houses an electronic component in which a heat source is housed.

High-performance electronic devices and the like ‧ The miniaturization system is progressing more and more, and the research on the heat-dissipating members that dissipate heat generated by the heat sources inside the electronic devices is actively carried out. Among them, in a heat dissipating member that is partially in contact with a heat source such as a back shell of a thin television, it is required to rapidly spread the generated heat in a wide area, that is, to have excellent thermal conductivity in the surface direction of the heat dissipating member. When the thermal conductivity in the surface direction is low, a temperature gradient occurs in the surface direction, and dispersion of the in-plane temperature occurs, causing problems such as color unevenness of the light-emitting surface or cracking of the glass substrate.

In particular, when the heat dissipating member is made of a metal material such as a steel plate, when the heat source is in contact with the metal material, it is extremely important that the thermal conductivity in the thickness direction of the metal material is not increased, but the thermal conductivity in the surface direction is increased. In this case, when the heat source is in contact with a heat dissipating member such as a steel plate, as a path for heat transfer from the heat source to the steel sheet to the outside, both the thickness direction and the surface direction are considered, and in a metal material such as a steel sheet having a thin plate thickness, Since the heat transfer distance in the thickness direction is short, the effect of increasing the heat transfer amount with respect to the thermal conductivity in the thickness direction is extremely small, and the heat transfer area in the surface direction is very wide, and the heat transfer rate in the surface direction can be expected to be improved. Significant increase in heat.

However, the fact that most of the research relating to the heat dissipating member is to rapidly diffuse the heat of the electronic machine component from the built-in heat source to the outside, the focus is on the thermal conductivity in the thickness direction of the heat dissipating member. The improvement is made without paying attention to the thermal conductivity of the surface of the heat dissipating member. For example, Patent Document 1 discloses a material which can absorb and diffuse heat with high efficiency, and has a metal material containing a coating layer of micro carbon fibers (representatively, carbon nanotubes) having an average aspect ratio of 3 or more. The method of measuring the rate is considered to evaluate only the thermal conductivity in the thickness direction.

Prior technical literature Patent literature

[Patent Document 1] JP-A-2005-199666

The present invention has been made in view of the above circumstances, and an object thereof is to provide a metal material which is coated with an excellent thermal conductive resin in the surface direction.

The resin-coated metal material of the present invention is a resin-coated metal material coated with a resin film containing thermally conductive particles on at least one surface of a metal substrate, and is characterized by a scanning electron in a cross section facing the surface of the resin film. When performing image analysis on a microscope photograph, the heat conductive particles observed in the measurement field of view satisfy the requirements of the following (1) to (3);

(1) The average value of the flatness ratio expressed by the value obtained by dividing the maximum length of the heat conductive particles by the minimum length (maximum length/minimum length) is 3.0 or more.

(2) When the inclination angle formed by the maximum length of the heat-conductive particles and the horizontal line in the plane direction is measured, the frequency ratio of the heat-conductive particles in which the inclination angle exists in the range of 0° or more and less than 30° is 40% or more.

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

In a preferred embodiment of the present invention, the resin film has a surface thermal conductivity of 1.5 W/mK or more.

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

In a preferred embodiment of the present invention, the resin coated metal material is used for an electronic machine component.

In the present invention, an electronic machine part having the above-described resin-coated metal material is also included in the scope of the present invention.

According to the present invention, as described above, it is possible to provide a metal material coated with a resin having high thermal conductivity in the surface direction. When the metal material of the present invention is used, since the temperature gradient due to the heat source contacting the metal material can be prevented from being lowered, it is particularly suitable as a heat sink for which high thermal conductivity is strongly required in the plane direction, or a back shell such as a thin television. Raw materials for electronic machine parts.

Form of implementing the invention

In order to provide a heat-dissipating member for an electronic device, in particular, a heat-receiving member in which a heat source is partially in contact with a heat-dissipating member, and a heat-dissipating member that strongly requires high thermal conductivity in a surface direction is provided, and a resin-coated metal material to be applied is repeatedly reviewed. . As a result, it has been found that the desired high thermal conductivity in the plane direction cannot be obtained by simply adding a plurality of high thermal conductive particles having a high thermal conductivity to the resin film (for example, refer to No. 3 and 4 of Table 2), but to thermally conductive particles. The shape or direction (defined as a horizontal angle with respect to the plane direction, the degree of inclination of the particles "inclination angle") is obtained by appropriately controlling the presence of a predetermined area ratio in the resin film, and the present invention has been completed.

In other words, the resin-coated metal material of the present invention is a resin coated with a resin film containing heat-conductive particles on at least one surface (heat source side) of the metal substrate, and is characterized in that a cross section of the resin film is scanned in the plane direction. When performing image analysis on a type electron microscope photograph (SEM photograph), the heat conductive particles observed in the measurement field of view satisfy the requirements of the following (1) to (3);

(1) The average value of the flatness ratio expressed by the value obtained by dividing the maximum length of the heat conductive particles by the minimum length (maximum length/minimum length) is 3.0 or more.

(2) When the inclination angle formed by the maximum length of the heat-conductive particles and the horizontal line in the plane direction is measured, the frequency ratio of the heat-conductive particles in which the inclination angle exists in the range of 0° or more and less than 30° is 40% or more.

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

As described above, the feature of the present invention is to specify the requirements of the above (1) to (3), which contribute greatly to the improvement of the thermal conductivity in the plane direction. As will be confirmed by the examples described later, the above three requirements must be fully satisfied in the present invention, and any one of the elements that does not satisfy the present invention does not have the desired characteristics.

First, the flattening ratio defined in the above (1) and the inclined angle defined in the above (2) will be described in detail with reference to Fig. 1 . Fig. 1 is a view schematically showing thermally conductive particles obtained by an image analysis means which will be described in detail later.

The flatness ratio defined in the above (1) is calculated from the ratio of the maximum length shown in Fig. 1 to the minimum length calculated based on the maximum length (maximum length/minimum length). The minimum length refers to the length at which the width of the parallel line becomes the smallest 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 "the flattening rate of the heat conductive particles".

The inclination angle (direction) defined in the above (2) means an angle formed by a horizontal line extending in the plane direction and a line extending the maximum length and intersecting the horizontal line as shown in Fig. 1 . Here, the angle formed by the horizontal line in the plane direction means an angle in a direction parallel to the surface of the resin film in a plane perpendicular to the surface of the resin film. Next, the number (frequency) of the thermally conductive particles existing in the range of the inclination angle of 0 to 180° was measured every 10° according to an analysis procedure described later, and a skew angle frequency distribution map was prepared. For reference, the upper graph of Fig. 2 shows a skew angle frequency distribution map of No. 9 of Table 1 of the embodiment to be described later. The inclination angles (10°, 20°, and maximum 180°) are plotted on the horizontal axis of Fig. 2, and are present in the bar graph as being above 0° and not above 10°, 10° or more with respect to the respective inclination angles. Frequency of heat-conductive particles up to 20°. In the present invention, the result of the inclination angle of 0° or more and less than 10° and more than 170° and 180° or less is considered to be equivalent to the enantiomer, and will be present at the respective inclination angles. The frequency of the thermally conductive particles in the range is added. When the entire tilt angle range (0 to 180°) is divided every 10°, as described above, 0° or more and less than 90° are regarded as “above, not reached” and will be from 90° to 180°. It is regarded as "exceeded or below". Furthermore, only 90° is included in the range of “80° or more and less than 90°” or “over 90° and 100° or less”. Thereby, the frequency of all the particles existing in the range of the inclination angle of 0 to 180° can be expressed as the frequency of the particles existing in the range of the inclination angle of 0 to 90°.

The lower diagram of FIG. 2 is a heat transfer particle having a tilt angle frequency distribution map (inclination angle of 0 to 180°) shown in the upper diagram of FIG. 2 as described above, and having a tilt angle of 0 to 90°. The frequency is expressed in units of 10°. In the present invention, based on the oblique angle frequency distribution map of the lower graph of FIG. 2 thus obtained, the total of the frequencies existing in the range of the inclination angle of 0 to 30° is divided by the inclination angle of 0 to 90°. The value after the entire frequency (all frequencies) in the range is defined as the "frequency ratio of the thermally conductive particles in the range where the inclination angle exists in the range of 0° or more and less than 30°".

Next, the usefulness of the present invention will be described in detail with reference to FIGS. 3 and 4. In addition, FIG. 3 is a photograph showing the SEM image and image analysis result of No. 9 (inventive example) of Example 1 which satisfies the requirements of the above (1) to (3), and FIG. 4 does not satisfy the above ( A photograph of No. 11 (Comparative Example) of Example 1 of the requirement of 3).

As shown in Fig. 3, in the example of the present invention, the particles having the predetermined flat shape and having the specified inclination angle are substantially continuous in the plane direction, and are mostly overlapped while being appropriately overlapped. As a result, the hot passage (path) is formed toward the surface direction, and the thermal conductivity of the surface is judged to be high. For reference, in the image analysis result of FIG. 3, the flow direction of heat is indicated by →.

On the other hand, in the comparative example, as shown in FIG. 4, there are several voids in which the particles do not exist in the plane direction. Therefore, the hot path in the plane direction is broken, and the thermal conductivity in the direction of the plane is judged to be low.

For reference, the results of Example 1 other than the above are shown in FIGS. 5, 6A, 6B, 10A to 10C, and 11. 5, FIG. 10A, and FIG. 10B show No. 9, 10, 12, 14, 15, 16, 17, 19, 20 of the first embodiment which fully satisfy the requirements of the above (1) to (3). In the SEM image and the image analysis result of the example of the present invention, it is understood that a heat path for improving the thermal conductivity in the plane direction is formed in the same manner as in the above-described FIG. 3 . On the other hand, FIGS. 6A, 6B, and 11 are photographs of No. 2 to 8 and 18 (all comparative examples) which do not satisfy any of the above-described items (1) to (3). In FIGS. 6A, 6B, and 11, it is understood that the path for the heat having a higher thermal conductivity in the plane direction is blocked as in the case of FIG. 4 described above.

A metal material coated with a resin that satisfies the requirements of the above (1) to (3), the thermal conductivity of the resin film in the surface direction is as high as 1.5 W/mK or more (preferably 1.55 W/mK or more, and particularly preferably 1.6). Above W/mK, more preferably 1.65 W/mK or more, and even more preferably 1.7 W/mK or more. According to the present invention, as shown in the examples below, the surface thermal conductivity of the resin film obtained is 2.0 W/mK or more, and more preferably 2.5 W/mK or more.

Here, the thermal conductivity in the plane direction is the optical AC thermal constant using a dedicated measuring device [Shenku-Riko. Inc. (now ULVAC-RIKO. Inc.)). The thermal diffusivity obtained by the measuring device PIT-R1 type" is calculated based on the following formula (1). This apparatus is particularly suitable as a device for measuring the thermal diffusivity in the plane direction of a thin sample having a thickness of 0.3 mm or less.

Thermal conductivity in the plane direction (W/mK) = thermal diffusivity (×10 ^-6 × m ² /sec) × specific heat (J/gK) × density (g/cm ³ ) ‧‧‧(1)

The method of measuring the thermal diffusivity in the above formula (1) will be described with reference to Fig. 7 . Fig. 7 is a schematic view showing the configuration of the above-described measuring device used in the present invention. As shown in FIG. 7 , in the above-described measuring device, the sample plate (the manufacturing method is described later) fixed in the device is irradiated with light of an alternating current waveform, and the shutter is moved in the direction of the plate surface of the sample to shield the light. The gradient d of the logarithm (ln∣Tac∣) of the absolute value of the alternating current temperature Tac measured by the thermocouple mounted on the surface opposite to the light-irradiating surface from the moving direction distance L of the sample in the direction of the sheet surface, according to the following formula (2) Calculate the thermal diffusivity D. In the following examples, the measurement environment was at room temperature in the atmosphere, and the measurement frequency [f in the following formula (2)] was 0.1 Hz.

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

The method of producing the sample plate fixed to the above measuring device is as follows.

First, a resin film sample for measuring the thermal diffusivity is prepared (in the examples described later, a polyimide film coated with a resin having a width of about 5 mm and a length of about 10 mm) is used. The size of the sample to be cut may be about 5 mm in width, and the length may be longer than 10 mm.

Next, as shown in FIG. 7, the light-receiving surface of the said sample was blackened. Specifically, an attached carbon sprayer (not shown) was used to spray carbon from a place of about 30 cm from the sample to blacken the sample so that the surface became as black. Further, a sample plate with a thermocouple was attached to the side opposite to the light receiving surface of the sample. Specifically, as shown in Fig. 7, only the necessary and minimum amount of silver paste was applied at the intersection of the thermocouple sample plate and the sample plate to adhere the sample to the thermocouple. At this time, if the resin film is thin, the warpage of the sample is observed. In this case, the sample can be cut long and fixed on the thermocouple sample plate.

In this manner, a sample plate in which the light-receiving surface was blackened and a galvanic sample plate was attached to the opposite side of the light-receiving surface was obtained, and the sample plate was fixed to the measuring device.

In addition, the specific heat of the resin film sample in the above formula (1) was measured at room temperature using a differential scanning calorimetry (DSC220C manufactured by Seiko Instruments Inc.). In addition, in order to accurately measure the density [weight/(length × horizontal × thickness)] of the resin film sample in the above formula (1), the vertical and horizontal dimensions (mm) are accurately measured using a vernier caliper, and the flattening ratio is used. The film thickness (μm) was determined from the SEM cross-sectional photograph used in the measurement.

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

Next, the measurement procedures of the above (1) to (3) will be described in detail.

First, the surface of the resin-coated metal material parallel to the resin film is cut so that the cross section of the resin film in the surface direction is exposed. A SEM cross-sectional photograph of the cross section of the surface of the resin film was taken using a scanning electron microscope (SUPRA35, manufactured by Carl Zeiss). The observation magnification was 1500 times, and the reflected electron image of the SEM of the observation area of 600 μm × 800 μm per field of view was taken, and 20 places (n number = 20) were observed in total. The photographed SEM photograph was processed by an image analysis apparatus (manufactured by NIRECO, LUZEX AP 2006.11), and the maximum length, the minimum length, and the average area ratio were obtained. Further, depending on the type of the additive such as the thermally conductive particles contained in the resin film, the SEM image may not be sharp. In this case, an SEM photograph is printed, and a PET film is attached thereon, and the additive portion is drawn with a black singular pen. The image is in image parsing.

In the above (1), in the present invention, the average value of the flatness ratio of the thermally conductive particles is preferably as large as possible, and is preferably 3.2 or more, and more preferably 3.5 or more. In addition, the upper limit of the average value of the flatness ratio is not particularly limited, but is preferably about 20.0, more preferably 19.0, in view of applicability or the like.

Further, in the above (2), in the present invention, the inclination angle is 0. The frequency ratio of the thermally conductive particles in the above range of less than 30° is preferably as good as possible, preferably 42% or more, more preferably 45% or more.

Further, in the above (3), in the present invention, the area ratio of the thermally conductive particles is preferably as large as possible, and is preferably 32% or more, more preferably 35% or more. In addition, the upper limit of the area ratio is not particularly limited, but is preferably 60%, more preferably 55%, in view of workability, corrosion resistance, and the like.

The present invention has been described above with reference to the requirements of the above (1) to (3).

The heat conductive particles used in the present invention are not particularly limited, and a general user in a heat dissipating member or the like can be used. Specifically, those having a high thermal conductivity of about 30 W/mK or more in terms of thermal conductivity are preferably used, and representative examples thereof include copper, aluminum, graphite, Al ₂ O ₃ , SiC, and the like. It is known that those having a high thermal conductivity are themselves capable of maintaining a high surface when added to a resin film by appropriately controlling their shape or inclination angle as confirmed by the examples described later. Directional thermal conductivity.

The preferred average particle diameter of the thermally conductive particles is approximately 1 to 40 μm, more preferably 1.5 to 35 μm. The average particle diameter can be measured, for example, by a laser diffraction ‧ scattering method (mirco-track method). When a commercially available product is used as an example described later, the average particle diameter provided by the manufacturer can be referred to. In detail, the average particle diameter of the thermally conductive particles is preferably appropriately controlled in relation to the thickness of the resin film. When the average particle diameter of the thermally conductive particles is too large, the dispersion of the inclination angle of the thermally conductive particles in the resin film becomes large, and the requirements of the above (2) cannot 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 with respect to the thickness of the resin film.

Commercially available products can be used as the thermally conductive particles used in the present invention. Specifically, in addition to those used in the examples described later, for example, copper of 1200YP manufactured by Mitsui Mining & Smelting Co., Ltd.; MH-8802 manufactured by Asahi Kasei Chemicals Corporation, Aluminum of MC-606, ME-12, M-701, GX-2134, BS-200, etc.; SP-20 manufactured by Nippon Graphite Industory Co., Ltd., Ito Kokuen Co. Ltd., such as SRP-7, CNP15 and the like.

The shape of the metal material used in the present invention is not particularly limited, and a metal plate may be used as a representative, and pipes, wires, rods, and profiled materials other than the above may be used. Further, the type of the metal material is not particularly limited, and a user such as a casing of an electronic device component can be used. In the case of a metal plate, a steel plate can be exemplified, and a cold rolled steel plate, a hot rolled steel plate, a stainless steel plate, or the like can be exemplified. Further, various plating such as an Al-plated copper plate or a Cu-plated steel plate such as an electrogalvanized steel sheet (EG), a hot-dip galvanized steel sheet (GI), an alloyed hot-dip galvanized steel sheet (GA), or an Al-Zn-plated steel sheet may be used. Steel plate; steel plate treated with a surface treatment such as chromate treatment or phosphate treatment; and non-chromate treated steel sheet. Alternatively, non-ferrous metal sheets may also be used.

The resin film containing the heat-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 to the surface direction of the metal material. The resin film can be provided not only on one side but also on both sides.

The resin (base resin) constituting the resin film used in the present invention is not particularly limited, and it is preferred to select a suitable resin mainly in accordance with the use of the metal material. As described above, the characteristic portion of the present invention is in the aspect of improving the thermal conductivity in the plane direction, and particularly specifies the requirements of the suitable heat-conductive particles. The other elements are not particularly limited as long as the effects of the present invention are not impaired. The metal material of the present invention is suitable for use in a casing of an electronic component. If good workability is required in consideration, it is preferred to use a polyester resin or an epoxy resin, a blend thereof or a modified resin. Of course, the aim is not limited to this, and various resins which are useful for improving workability can be selected as appropriate. Further, in the case where corrosion resistance or the like is also required, a resin suitable for improvement in corrosion resistance can be selected and used. The change of the resin used in the present invention can be suitably carried out by the person skilled in the art in accordance with the use of the metal material.

In addition to the heat conductive particles and the resin, the resin film may be added with an additive component usually added to the resin film. As the above-mentioned additive component, for example, a rust preventive pigment, an antistatic agent, a weather resistance improving agent, and the like can be exemplified, and it can be added within a range that does not impair the effects of the present invention. Alternatively, for the purpose of improving heat dissipation, a well-known heat dissipation additive (representatively, carbon black, oxides, sulfides, carbides, etc. of Co, Ni, Cu, Mn, Ag, Sn, etc.) may be added. And TiO ₂ , ceramics, iron oxide, aluminum oxide, barium sulfate, barium oxide, etc.).

Further, there may be other films on the resin film, and such a metal material is also included in the scope of the present invention. For example, for the purpose of improving the scratch resistance and the finger print resistance, a well-known clear film may be coated on the resin film.

The metal material coated with the resin of the present invention can be coated on the surface of the metal material by a well-known coating method by dissolving or dispersing the above-mentioned base resin and heat conductive particles in a solvent, if necessary, other additives. It is produced by coating and drying, or by heating and baking. The coating method is not particularly limited, and for example, the surface is cleaned, and if necessary, on the surface of the substrate to which the pre-coating treatment (for example, phosphate treatment, chromate treatment, etc.) is applied, roll coating is used. A method of applying a coating by a roll coater method, a spray method, a curtain flow coater method, or the like, drying it by a hot air drying oven, or hardening a grill.

The content of the heat-conductive particles contained in the above-mentioned coating material varies depending on the type of the particles or the type of the resin or solvent used in combination, and is difficult to determine, but is roughly equivalent to 100 parts by mass of the coating material. It is preferably from 10 to 70 parts by mass, more preferably from about 15 to 65 parts by mass. Similarly, the content of the base resin contained in the above-mentioned coating material varies depending on the type of the resin or the type of the heat-conductive particles or solvent used in combination, and is difficult to determine, but is substantially equivalent to 100 parts by mass of the coating material. Preferably, it is about 5 to 35 parts by mass, more preferably about 7 to 33 parts by mass.

[Examples]

The present invention will be more specifically described by the following examples, but the present invention is not limited by the following examples, and may be modified and implemented within the scope of the following hereinafter. Within the technical scope of the invention.

Example 1

(I) Modulation of paint

The thermally conductive particles of the symbols A to D shown below were mixed at the ratios shown in Table 1; a mixed solvent of xylene and cyclohexanone (xylene: cyclohexanone = 1:1); polyester resin (Toyo Textile Co., Ltd.) Organic solvent-soluble polyester resin "Byron (VYLON, registered trademark) 650" manufactured by TOYOBO Co., Ltd.) and melamine resin (manufactured by Sumitomo Chemical Co., Ltd.) Sumimar (SUMIMAL, registered trademark) M-40ST", solid content 80%) base resin (masterbatch resin) mixed in a mass ratio (dry ratio) of 100:20, using a manual homogenizer (hand The homogenizer was vigorously stirred to prepare a coating (No. 2 to 20 in Table 1). For reference, the average particle diameters of the symbols A to D (displayed by the manufacturer) are also shown in Table 1. Moreover, for comparison, only the base resin which does not add a heat-conductive particle is prepared (No. 1 of Table 1).

Mark A: Spherical copper powder (1300Y made by Mitsui Metal Plating)

Mark B1: Concave copper powder (MA-CO8J made by Mitsui Mining and Metals Co., Ltd.)

Mark B2: Concave copper powder (MA-CO4J manufactured by Mitsui Mining and Metals Co., Ltd.)

Mark C1: Flat copper powder (1100YP made by Mitsui Mining and Metals Co., Ltd.)

Mark C2: Flat copper powder (1400YP made by Mitsui Mining and Metals Co., Ltd.)

Mark C3: Flat copper powder (1300YP made by Mitsui Mining and Metals)

Mark C4: (2L3N made by Fukuda Metal Foil Industry)

Mark D: Flat aluminum powder (GX-40A by Asahi Kasei Chemicals)

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

The flatness ratio of the thermally conductive particles of the element (1) specified in the present invention is measured as follows, and the ratio of the frequency of the thermally conductive particles in the range of 0° or more and less than 30° of the inclination angle of the element (2), and the requirements ( 3) The area ratio of the thermally conductive particles.

First, as the bottom plate, an electrogalvanized steel sheet (plate thickness: 0.8 mm, Zn adhesion amount: 20 g/m ² ) was used. On the bottom plate, each of the coating materials prepared as described above was applied by a bar coater, and baked at a maximum temperature (PMT) of 220 ° C for 2 minutes, followed by drying to obtain a resin film having a thickness of 10 to 20 μm. Resin coated metal plate.

The surface of the thus-obtained resin-coated metal sheet parallel to the resin film is cut, and for the cutting to a size of about 15 mm × 25 mm, the above-described requirements (1) to (3) defined in the present invention are measured in accordance with the above-described measurement procedure. ).

(II) Determination of thermal conductivity in the plane direction

A Teflon (trademark)-treated polyimine film ("Kapton 500F" manufactured by Toray DuPont, thickness: 125 μm) was prepared as a substrate for the production of a resin film sample for thermal diffusivity measurement. On the substrate, each of the coating materials was applied in the same manner as in the above (II) to obtain a resin-coated polyimide film having a resin film having a thickness of 10 to 20 μm. The measurement sample having a width of 5 mm and a length of about 10 mm was cut out using the resin film, and the thermal conductivity in the plane direction was measured by the above method. The resin film sample used for the measurement was peeled off from the polyimide film and used. In the present embodiment, those having a surface thermal conductivity of 1.5 W/mK or more were regarded as pass (○).

The results of these are summarized in Table 2.

For reference, FIGS. 8, 9A, 9B, 12A to 12C, and 13 each show No. 9, 10, 12, 14, 15, 16, 17, 19, 20 (invention example), and No. .2~8, 11 and 18 (comparative examples) slope angle frequency distribution map (inclination angle 0~90°). The diagram of No. 9 in Fig. 8 is the same as the lower diagram of Fig. 2 described above.

According to Table 2, it can be examined as follows. First, the thermally conductive particles in the resin film completely satisfy No. 9, 10, 12 to 17, 19, and 20 of the above-mentioned requirements (1) to (3) defined by the present invention, compared with No. 1 in which no heat conductive particles are added. , the high thermal conductivity in the plane direction is obtained.

On the other hand, although the same heat conductive particles as described above were added, the following examples which did not satisfy any of the requirements specified in the present invention did not provide desired characteristics. In detail, No. 4 which does not satisfy the flatness ratio of the above (1) does not satisfy the flat ratio of the above (1) and No. 3 of the frequency ratio of the above (2), and does not satisfy the flatness ratio of the above (1) and the above. No. 2, 5, and 7 of the area ratio of (3) do not satisfy the requirements of No. 6 of the above (1) to (3), and No. 8, 10, and 18 which do not satisfy the area ratio of the above (3). , the system can not get high surface thermal conductivity.

Fig. 1 is a view schematically showing heat conductive particles in a resin film.

Fig. 2 is a diagram showing the distribution of the oblique angle frequency of No. 9 (inventive example) of the first embodiment.

Fig. 3 is a photograph showing an SEM image and an image analysis result of No. 9 (inventive example) of Example 1.

4 is a photograph showing an SEM image and an image analysis result of No. 11 (Comparative Example) of Example 1. FIG.

Fig. 5 is a photograph showing SEM images and image analysis results of Nos. 14 and 16 (inventive examples) of Example 1.

Fig. 6A is a photograph showing SEM images and image analysis results of Nos. 2 to 5 (comparative examples) of Example 1.

Fig. 6B is a photograph showing SEM images and image analysis results of Nos. 6 to 8 (comparative examples) of Example 1.

Fig. 7 is a schematic view showing the configuration of a measuring device for the thermal conductivity in the surface direction used in the present invention.

Fig. 8 is a diagram showing the distribution of the oblique angle frequency of Nos. 9, 14, and 16 (inventive examples) of the first embodiment.

Fig. 9A is a diagram showing a skew angle frequency distribution of Nos. 2 to 6 (comparative examples) of the first embodiment.

Fig. 9B is a distribution diagram of the oblique angle frequency of Nos. 7, 8, and 11 (comparative examples) of the first embodiment.

Fig. 10A is a photograph showing SEM images and image analysis results of Nos. 9, 10, 12, and 15 (inventive examples) of Example 1.

Fig. 10B shows photographs of SEM images and image analysis results of Nos. 17, 19, and 20 (inventive examples) of Example 1.

Fig. 11 is a photograph showing an SEM image and an image analysis result of No. 18 (Comparative Example) of Example 1.

Fig. 12A is a view showing a distribution of the inclination angle frequency of Nos. 9, 10, and 12 (inventive examples) of the first embodiment.

Fig. 12B is a diagram showing the distribution of the skew angle frequency of Nos. 15 and 17 (inventive examples) of the first embodiment.

Fig. 12C is a view showing the distribution of the skew angle frequency of Nos. 19 and 20 (inventive examples) of the first embodiment.

Fig. 13 is a diagram showing the distribution of the oblique angle frequency of No. 18 (comparative example) of the first embodiment.

Claims (5)

A metal material coated with an excellent thermal conductive resin in a surface direction, which is a resin-coated metal material coated with a resin film containing thermally conductive particles on at least one surface of a metal substrate, and is characterized by being in the resin film When the image is analyzed by scanning electron micrographs of the cross section in the plane direction, the thermally conductive particles observed in the measurement field of view satisfy the requirements of the following (1) to (3); (1) the maximum length of the thermally conductive particles is divided by the minimum The average value of the flatness ratio expressed by the value after the length (maximum length/minimum length) is 3.0 or more. (2) When the inclination angle formed by the maximum length of the heat-conductive particles and the horizontal line in the plane direction is measured, the inclination angle exists at 0°. The ratio of the frequency of the thermally conductive particles in the range of less than 30° is 40% or more, and (3) the area ratio of the thermally conductive particles is 30% or more. The resin-coated metal material according to the first aspect of the invention, wherein the surface thermal conductivity of the resin film is 1.5 W/mK or more. The resin-coated metal material according to claim 1 or 2, wherein the heat conductive particles are copper, aluminum or graphite. A resin-coated metal material as claimed in claim 1 or 2, which is used in electronic machine parts. An electronic machine part having the resin coated metal material of claim 4 of the patent application.