TW201910131A - Thermally conductive resin molded article - Google Patents

Abstract

A thermally conductive resin molded article including a resin and a thermally conductive filler that includes a first thermally conductive filler and a second thermally conductive filler having a smaller grain size than the first thermally conductive filler, wherein the thermally conductive filler content is 30-50% by volume, the first thermally conductive filler comprises boron nitride having a grain size of 30 [mu]m or greater and an aspect ratio of 10 or higher, the first thermally conductive foller content is 5-20% by volume, and the second thermally conductive filler comprises a material other than boron nitride.

Description

Heat conductive resin molded product

The present invention relates to a thermally conductive resin molded product.

In recent years, the high density and thinning of electronic equipment have developed rapidly, and the influence of heat generated from integrated circuits (ICs) or power components, high-brightness light-emitting diodes (LEDs) has become Major issues. In response to this problem, for example, the use of a sheet-like thermally conductive resin molded product is being promoted as a member that efficiently transfers heat between a heat generating body such as a wafer and a heat radiating body. Here, as a method of imparting high thermal conductivity to the resin molded article, it is known to align and disperse the thermally conductive filler in the resin in order to efficiently form the thermally conductive path.

Patent Document 1 proposes a manufacturing method of extruding a kneaded product containing scaly particles of resin and / or rubber and boron nitride into a plurality of band-shaped plasticizers, and using These are collected and sheet-hardened, or they are hardened while being sheet-shaped. Patent Literature 2 proposes a thermally conductive molded body as a thermally conductive molded body characterized by a silicone laminate containing 50% to 75% by volume of a thermally conductive filler It is cut in the stacking direction. The thermally conductive filler contains two types of boron nitride powder (A) and boron nitride powder (B) having different average particle diameters. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 08-244094 Patent Document 2: Japanese Patent Laid-Open No. 2010-260225

[Problems to be Solved by the Invention] The resin molded articles having thermal conductivity described in Patent Document 1 and Patent Document 2 preferably use a filler made of boron nitride as the thermally conductive filler. The filler made of boron nitride has the advantage of easily imparting excellent thermal conductivity. However, boron nitride is expensive, and when a large amount of filler made of boron nitride is contained as in Patent Document 1 and Patent Document 2, it is difficult to provide a resin molded product having thermal conductivity at low cost. On the other hand, in the case where only a filler made of boron nitride is used as the thermally conductive filler, if the content of the filler is small, it is difficult to align the filler. As a result, there is a problem that although the produced resin molded product uses a filler made of boron nitride, the thermal conductivity is poor.

The present invention has been made in view of such a problem, and an object thereof is to provide a thermally conductive resin molded product that has excellent thermal conductivity and can be manufactured at low cost. [Means to solve the problem]

(1) The thermally conductive resin molded article of the present invention includes a resin and a thermally conductive filler, the thermally conductive filler including a first thermally conductive filler and a second thermally conductive filler having a smaller particle size than the first thermally conductive filler, The thermally conductive resin molded article is characterized in that the content of the thermally conductive filler is 30% by volume to 50% by volume, and the first thermally conductive filler is comprised of a particle diameter of 30 μm or more and an aspect ratio of 10 or more For the boron nitride filler, the content of the first thermally conductive filler is 5% to 20% by volume, and the second thermally conductive filler is a filler containing materials other than boron nitride.

The thermally conductive resin molded article of the present invention suppresses the upper limit of the total content of the thermally conductive filler to 50% by volume, and contains a predetermined amount of the first thermally conductive filler containing boron nitride, and materials and particles other than boron nitride. The second thermally conductive filler having a smaller diameter than the first thermally conductive filler. Therefore, according to the thermally conductive resin molded article, even if the content of the first thermally conductive filler containing boron nitride is small, the first thermally conductive filler can be aligned, and the thermally conductive resin molded article is excellent in thermal conductivity. In addition, the thermally conductive resin molded article can be provided at low cost.

(2) In the thermally conductive resin molded article, the particle diameter of the second thermally conductive filler is preferably 3 μm to 20 μm. In this case, the second thermally conductive filler is suitable between the first thermally conductive fillers and improves the thermal conductivity of the thermally conductive resin molded product, and is also suitable for making the first 1 Thermal conductivity filler alignment.

(3) In the thermally conductive resin molded article, the second thermally conductive filler preferably contains magnesium oxide or magnesium carbonate. In this case, the second thermally conductive filler is preferably interposed between the first thermally conductive fillers to increase the thermal conductivity of the thermally conductive resin molded product, and is suitable for providing the thermally conductive resin molded product inexpensively. [Effect of invention]

The thermally conductive resin molded article of the present invention has excellent thermal conductivity. In addition, the thermally conductive resin molded article can be provided at low cost.

The embodiments of the present invention will be described below. In the present invention, the "thermally conductive resin molded product" includes a block produced by molding a raw material composition, and a cut product (including a sliced sheet) obtained by cutting the block. The concept of either. In this embodiment, a heat conductive sheet is taken as an example to describe an embodiment of a heat conductive resin molded product.

1 is a cross-sectional view schematically showing a thermally conductive sheet according to an embodiment of the present invention, and is a cross-sectional view parallel to the thickness direction of the thermally conductive sheet. In addition, FIG. 1 is a schematic diagram, and each member (especially the first thermally conductive filler and the second thermally conductive filler) does not accurately reflect the actual size. The thermally conductive sheet 1 of the present embodiment is disposed between a heat generating member such as an IC chip and a heat dissipating member such as a heat sink, and one side thereof is used in contact with the heat generating member and the other side in contact with the heat dissipating member.

As shown in FIG. 1, the thermally conductive sheet 1 has a matrix component 2, and a first thermally conductive filler 4 and a second thermally conductive filler 5. The first thermally conductive filler 4 is in the approximate thickness direction of the thermally conductive sheet 1 (in FIG. 1 is Up and down direction). In the thermally conductive sheet 1, the thermally conductive path formed by the first thermally conductive filler 4 and the second thermally conductive filler 5 is formed in the substantially thickness direction of the thermally conductive sheet 1. Therefore, the thermal conductivity sheet 1 is excellent in thermal conductivity in the thickness direction. In addition, in the thermally conductive sheet, components other than the thermally conductive filler are collectively referred to as matrix components.

The thermally conductive sheet 1 is a sheet-like sliced piece formed by adhering a thin resin sheet in which the first thermally conductive filler 4 in the matrix component 2 is aligned and dispersed in the plane direction in a state of being folded in the vertical direction ( slice). There are also cases where such a thermally conductive sheet 1 has a weld line 6 formed in a substantially thickness direction.

The matrix component 2 contains at least a resin (including rubber). The resin can be appropriately selected from various conventionally known resins and used. Specifically, for example, ethylene-α-olefin copolymers such as polyethylene, polypropylene, and ethylene-propylene copolymers, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and ethylene- Fluorine resins such as vinyl acetate copolymer, polyvinyl alcohol, polyacetal, polyvinylidene fluoride or polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene Ethylene formate, polystyrene, polyacrylonitrile, styrene-acrylonitrile copolymer, acrylonitrile butadiene-styrene copolymer (Acrylonitrile Butadiene Styrene, ABS) resin, polyphenylene ether, modified polyphenylene ether , Aliphatic Polyamides, Aromatic Polyamides, Polyamide Amide, Polymethacrylic acid or its esters, Polyacrylic acid or its esters, Polycarbonate, Polyphenylene sulfide, Polysulfone, Polyether Ballast, polyether nitrile, polyether ketone, polyketone, liquid crystal polymer, silicone resin, ionic polymer, etc. In addition, for example, styrene-based thermoplastic elastomers such as styrene-butadiene copolymer or its hydrogenated polymer, styrene-isoprene block copolymer or its hydrogenated polymer, olefin-based thermoplastic elastomer, chlorine Ethylene-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, etc. Furthermore, for example, silicone rubber, acrylic rubber, butyl rubber, fluororubber, nitrile rubber, hydrogenated nitrile rubber, and the like can also be used. These can be used alone or in combination of two or more. Among these, silicone rubber is preferred in terms of excellent flexibility, shape-followability when formed into a molded body, adhesion to a heating surface when contacting electronic parts, and heat resistance.

Examples of the silicone rubber include those obtained by crosslinking polymers (silicone) having a silicone skeleton. Here, the crosslinking of the silicone may be a peroxide crosslinking or an addition reaction type crosslinking, but it is preferably a peroxide crosslinking. The silicone rubber obtained by crosslinking by peroxide crosslinking has excellent heat resistance.

The silicone rubber is preferably, for example, a mixture of silicone in which all of the side chains are methyl and does not contain unsaturated groups, and a mixture of silicones having a part of the side chain (including the terminal) having a vinyl group for peroxide crosslinking. Successor. At this time, the silicone having vinyl in a part of the side chain can also be regarded as a crosslinking agent for the silicone in which the side chain is all methyl and does not contain unsaturated groups.

Specific examples of silicones having a vinyl group as part of the side chain include, for example, dimethylvinylsiloxyoxy-blocked dimethylpolysiloxane at both ends of the molecular chain, and methylphenyl at both ends of the molecular chain. Vinylsiloxy-blocked dimethylpolysiloxane, molecular chain both ends dimethylvinylsiloxy-blocked dimethylsiloxane · methylphenylsiloxane copolymer, molecular chain both ends dimethyl Vinylsiloxy-blocked dimethylsiloxane · methylvinylsiloxane copolymer, molecular chain both ends trimethylsiloxy-blocked dimethylsiloxane · methylvinylsiloxane copolymerization Substances, dimethylvinylsiloxy groups at both ends of the molecular chain block methyl (3,3,3-trifluoropropyl) polysiloxane, silanol groups at both ends of the molecular chain block dimethylsiloxane Vinyl vinyl siloxane copolymer, silanol groups at both ends of the molecular chain blocked dimethyl siloxane, methyl vinyl siloxane, methyl phenyl siloxane copolymer, etc. These can be used alone or in combination of two or more.

Examples of the organic peroxide when performing the peroxide crosslinking include, for example, benzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (third butyl) Base peroxide) hexane, di-tertiary butyl peroxide, tertiary butyl perbenzoate, etc. These can be used alone or in combination of two or more. Furthermore, a crosslinking accelerator or a crosslinking accelerator may be used in combination during crosslinking.

In addition to the resin, the matrix component 2 may contain a crosslinking agent, a crosslinking accelerator, and a crosslinking accelerator as described above. In addition, the base component 2 may contain general additives such as reinforcing agents, fillers, softeners, plasticizers, anti-aging agents, adhesion-imparting agents, antistatic agents, kneading adhesives, flame retardants, coupling agents and the like.

The thermally conductive sheet 1 contains a first thermally conductive filler 4 and a second thermally conductive filler 5 having a smaller particle size than the first thermally conductive filler 4 as two types of thermally conductive fillers. The first thermally conductive filler 4 contains boron nitride (BON nitride (BN)). Therefore, the thermally conductive sheet 1 has excellent thermal conductivity. The shape of the first thermally conductive filler 4 is not particularly limited as long as it has a predetermined particle size and aspect ratio. Specific shapes of the first thermally conductive filler 4 include, for example, scaly, plate, film, fibrous, cylindrical, prismatic, elliptical, and flat shapes. Among these shapes, scales are preferred. The reason is that because of the high aspect ratio and isotropic thermal conductivity in the plane direction, the thermal conductivity of the molded product becomes higher when the scale-shaped thermally conductive filler is aligned.

The particle diameter of the first thermally conductive filler 4 is 30 μm or more. If the particle size is less than 30 μm, it may be difficult to form a thermal conduction path and the thermal conductivity may be poor. On the other hand, from the viewpoint of workability when producing a thermally conductive resin molded article, the preferable upper limit of the particle diameter of the first thermally conductive filler 4 is 100 μm.

The aspect ratio of the first thermally conductive filler 4 is 10 or more. In this case, the second thermally conductive filler 5 having a smaller particle size than the first thermally conductive filler 4 is dispersed in the gaps of the first thermally conductive filler 4 and easily forms a thermal conduction path, and the first thermally conductive filler 4 is likely to be easier 2 alignment. On the other hand, the upper limit of the aspect ratio of the first thermally conductive filler 4 is preferably 100. In this case, it is easy to fill the first thermally conductive filler in the thermally conductive resin molded article, and the processability when producing the thermally conductive resin molded article is also excellent.

In the present invention, the so-called "particle size" of the thermally conductive filler is the concept of average particle size in the measurement of particle size distribution. The average particle diameter was measured by a laser backscattering method (device: Microtrac MT3300EXII manufactured by Microtrac-Bel Co., Ltd.). In addition, in the present invention, the "aspect ratio" of the thermally conductive filler is the concept of the average value of the ratio of the major axis to the minor axis. In the aspect ratio, 200 or more particles are arbitrarily selected from the image captured by a scanning electron microscope (SEM), and the ratio of the major axis to the minor axis is calculated and the average value is calculated. Here, regarding the long axis and the short axis, in the observation image of each particle, the length of the longest part is set as the long axis, and the length of the part that passes through the midpoint of the long axis and reaches the long axis is set as the short path.

The second thermally conductive filler 5 has a smaller particle size than the first thermally conductive filler and contains materials other than boron nitride. The second thermally conductive filler 5 only needs to be made of materials other than boron nitride and has thermal conductivity. Specific examples of the second thermally conductive filler 5 include graphite, carbon fiber, carbon nanotube (CNT), mica, alumina, aluminum nitride, silicon carbide, silica, zinc oxide, and oxide. Fillers for magnesium, calcium carbonate, magnesium carbonate, molybdenum disulfide, copper, aluminum, etc. Among these, the thermally conductive filler containing magnesium oxide and the thermally conductive filler containing magnesium carbonate are preferable. The reason is that it is suitable for interposing the first thermally conductive fillers 4 to improve the thermal conductivity of the thermally conductive sheet 1, and is suitable for providing the thermally conductive sheet 1 at a low cost.

The shape of the second thermally conductive filler 5 is not particularly limited, and specific shapes include, for example, spherical, scaly, plate, film, cylindrical, prismatic, elliptical, and flat shapes. The shape of the second thermally conductive filler 5 is preferably spherical or scaly. The reason is that, in this case, it is easy to form a thermal conduction path between the first thermally conductive fillers 4 and it is suitable to align the first thermally conductive fillers 4.

The particle size of the second thermally conductive filler 5 is not particularly limited as long as it is smaller than the particle size of the first thermally conductive filler 4, but it is preferably 3 μm to 20 μm. If the particle size of the second thermally conductive filler 5 is within the above range, it is more suitable for forming a thermal conduction path between the first thermally conductive fillers 4 and aligning the first thermally conductive filler 4. Furthermore, if the particle diameter of the second thermally conductive filler 5 is within the above range, it is suitable to suppress the surface roughness of the thermally conductive sheet 1 and reduce the contact thermal resistance when contacting the heat generating member or heat dissipating member (the surface of the thermally conductive sheet 1) Thermal resistance). On the other hand, if the particle diameter of the second thermally conductive filler 5 exceeds 20 μm, the first thermally conductive filler 4 becomes difficult to align, and the thermal conductivity of the thermally conductive sheet 1 may be poor. In addition, when the particle diameter of the second thermally conductive filler 5 is less than 3 μm, the thermal conductivity of the thermally conductive sheet 1 may be poor depending on the material of the second thermally conductive filler 5. For example, in the case where the material of the second thermally conductive filler 5 is magnesium oxide or magnesium carbonate, there may be foaming of the second thermally conductive filler 5 during the manufacturing process of the thermally conductive sheet 1. If there is a bubble, the thermal conductivity of the manufactured thermal conductive sheet 1 may decrease. The particle size of the second thermally conductive filler 5 is more preferably 5 μm to 20 μm, further preferably 5 μm to 15 μm, and particularly preferably 5 μm to 10 μm.

The upper limit of the aspect ratio of the second thermally conductive filler 5 is preferably 100. The reason is that it is easy to fill the second thermally conductive filler in the thermally conductive resin molded product, and also the processability when producing the thermally conductive resin molded product is excellent. The lower limit of the aspect ratio of the second thermally conductive filler 5 is not limited, and the aspect ratio of the second thermally conductive filler 5 may be 1 or more. The method for measuring the particle size and aspect ratio of the second thermally conductive filler 5 is the same as the method for measuring the particle size and aspect ratio of the first thermally conductive filler 4.

The content of the heat conductive filler (the total content of the heat conductive filler) in the heat conductive sheet 1 is 30% by volume to 50% by volume. If the total content of the thermally conductive filler is less than 30% by volume, sufficient thermal conductivity cannot be ensured. In addition, if the content exceeds 50% by volume, the processability when producing a thermally conductive resin molded product is deteriorated, and it is difficult to provide a thermally conductive resin molded product inexpensively.

The content of the first thermally conductive filler 4 in the thermally conductive sheet 1 is 5 to 20% by volume. In this case, the first thermally conductive filler can be aligned to ensure thermal conductivity. On the other hand, if the content of the first thermally conductive filler 4 is less than 5% by volume, even if the first thermally conductive filler is aligned, sufficient thermal conductivity cannot be ensured. In addition, if the content exceeds 20% by volume, it is difficult to provide a thermally conductive resin molded article at low cost.

The content of the second heat conductive filler 5 in the heat conductive sheet 1 is preferably 10% by volume to 45% by volume. If the content of the second thermally conductive filler 5 is less than 10% by volume, it is difficult to align the first thermally conductive filler during molding. On the other hand, if the content of the second thermally conductive filler 5 exceeds 45% by volume, the content of the first thermally conductive filler becomes too small, and sufficient thermal conductivity cannot be ensured. The content of the second thermally conductive filler 5 is more preferably 20% by volume to 45% by volume.

The thermally conductive sheet 1 of the present embodiment contains the first thermally conductive filler 4 and the second thermally conductive filler 5 as thermally conductive fillers. Here, the particle diameter D1 of the first thermally conductive filler 4 and the particle diameter D2 of the second thermally conductive filler 5 have a relationship of D1> D2. In addition, the thermally conductive sheet 1 may contain thermally conductive fillers other than the first thermally conductive filler 4 and the second thermally conductive filler 5 as long as the effects of the present invention are not impaired.

The thickness of the thermally conductive sheet 1 is not particularly limited, and is, for example, about 0.1 mm to 3.0 mm. In this case, the thermally conductive sheet 1 can be suitably used as a member that efficiently transfers heat between a heat generating member and a heat radiating member in electrical parts, automobile parts, and the like.

Next, the method of manufacturing the thermally conductive sheet of this embodiment will be described with reference to the drawings. FIG. 2 is a diagram schematically showing an extruder used in the production of a thermally conductive sheet according to an embodiment of the present invention. FIG. 2 shows a schematic cross-sectional view of the front end portion of the extruder 100 and the T-die. The raw material composition containing the thermally conductive filler introduced into the extruder 100 is stirred and kneaded by the screw 8 and introduced into the first gap 12 along the flow path 10.

The raw material composition put into the extruder 100 is first twisted in the vertical direction (thickness direction) through the first gap 12 and becomes a thin strip. When passing through the first gap 12, a shear force acts on the raw material composition, and the first thermally conductive filler mixed in the raw material composition is aligned in the flow direction of the raw material composition. Therefore, in the thin resin sheet precursor molded through the first gap 12, at least the first thermally conductive filler is aligned in the plane direction of the resin sheet precursor. In addition, when the second thermally conductive filler is a filler having an alignable shape, the second thermally conductive filler is aligned in the same direction as the first thermally conductive filler when passing through the first gap 12.

The gap of the first gap 12 (the vertical dimension in FIG. 2) is preferably 0.1 mm or more and 5.0 mm or less. If the gap of the first gap 12 is less than 0.1 mm, the extrusion pressure may rise unnecessarily, which may cause resin clogging. On the other hand, if the gap of the first gap 12 is greater than 5.0 mm, the degree of alignment of the thermally conductive filler with respect to the plane direction of the thin resin sheet precursor may decrease.

When the thin resin sheet precursor aligned in the plane direction of the first thermally conductive filler completely passes through the first gap 12, the flow direction of the sheet limited to the extrusion direction is released, and the flow direction changes to the extrusion direction And roughly vertical direction. The reason is that the cross-sectional area of the flow path 10 after passing through the first gap 12 is enlarged, and the length of the flow path 10 in the vertical direction becomes longer. After the sheet resin flow direction changes to a direction substantially perpendicular to the extrusion direction, the thin resin sheet precursor completely passes through the first gap 12 and is then extruded toward the second gap 14. As a result, the resin sheet precursor in the second gap 14 is in a state where the thin resin sheet precursor is laminated. At this time, most of the first thermally conductive filler is aligned in the thickness direction of the resin sheet precursor in the second gap 14 (the vertical direction in FIG. 2). After that, if necessary, the resin sheet precursor is heated under predetermined conditions to perform crosslinking, and then the resin sheet precursor is sliced in a direction perpendicular to the thickness direction as necessary. Through such steps, the thermally conductive sheet 1 is manufactured.

Here, the gap of the second gap 14 is preferably twice or more and 20 times or less the gap of the first gap 12. When the gap in the second gap 14 is less than twice the gap in the first gap 12, the first thermally conductive filler 4 may not be aligned in the thickness direction of the thermally conductive sheet 1. In addition, when the gap of the second gap 14 is greater than 20 times the gap of the first gap 12, a local turbulence of the resin sheet precursor is likely to occur, and as a result, it may sometimes be caused in the thickness direction of the thermal conductive sheet 1 The ratio of the aligned first thermally conductive filler 4 decreases. The gap of the second gap 14 is more preferably twice or more and 10 times or less the gap of the first gap 12. In addition, from the viewpoint that the resin sheet precursor easily flows uniformly in the vertical direction of the flow path 10, the center in the thickness direction in the first gap 12 and the center in the thickness direction in the second gap 14 are preferable In the same direction in the thickness direction.

The shape of the opening connected to the first gap 12 is not particularly limited, but it is preferable to set the side surface (upper and lower surfaces) of the opening on the upstream side as an inclined surface so as to reduce pressure loss. Regarding the side surface of the opening on the downstream side (Upper and lower surfaces) In order to efficiently align the thermally conductive filler in the thickness direction of the resin sheet, it is desirable to adjust the inclination angle (the angle formed by the extrusion direction and the inclined surface). The inclination angle can be set to, for example, 10 ° to 50 °, and more preferably 20 ° to 25 °. In addition, the opening connected to the first gap 12 does not need to have an inclination up and down, and only one of them may have an inclination. In addition, the depths of the first gap 12 and the second gap 14 (that is, the gaps of the first gap 12 and the second gap 14 in the direction substantially perpendicular to the paper surface in FIG. 2) are substantially the same throughout the T-die. In addition, the depth dimension of the first gap and the second gap is not particularly limited, and various design changes can be made according to the product width of the resin sheet.

The thermally conductive sheet according to the embodiment of the present invention can also be manufactured by the following manufacturing method. That is, it can also be produced by the following method: after preparing a raw material composition for manufacturing a thermally conductive sheet, using the raw material composition and using a previously known method to produce a plurality of sheets in which at least the first thermally conductive filler is aligned in the plane direction After the sheet-like object is laminated into a plurality of pieces to form a lump, the lump is stacked in a direction perpendicular to the direction in which the first thermally conductive filler is aligned (layering of the sheet-like object) Body) to cut. In the case of manufacturing a thermally conductive sheet by this method, crosslinking treatment may be performed at an appropriate timing as necessary. In addition, the thermally conductive sheet produced by this method also becomes a sheet having excellent thermal conductivity in which the first thermally conductive filler is aligned in the thickness direction of the thermally conductive sheet. [Example]

Next, the present invention will be further described in detail based on examples, but the present invention is not limited to the examples. (Example 1) In the formulation described in Table 1, the crosslinking agent and the first thermally conductive filler and the second thermally conductive filler (hereinafter, all are collectively referred to as raw material components) are kneaded with two rollers in the resin component. A ribbon sheet (a composition as a precursor) is obtained. As the resin component, silicone rubber "DY321005U manufactured by Toray Dow Corning" and a plasticizer (silicone oil manufactured by Shin-Etsu Chemical Co., Ltd .: KF-96-3000CS) were used. The cross-linking agent used "MR-53" and "RC-4 50P FD" manufactured by Toray Dow Corning. Table 1 shows the total content. As the first thermally conductive filler, a filler containing boron nitride (“XGP” (scaled, 35 μm particle size, approximately 30 aspect ratio) manufactured by Denka Co., Ltd.) is used. As the second thermally conductive filler, a filler containing magnesium carbonate (cubic shape, particle size 6 μm, aspect ratio about 1 (manufactured by Shendao Chemical Industry Co., Ltd.)) was used.

Then, for the produced strip-shaped sheet, a vertical alignment die (die opening) having a first gap of 1 mm and a second gap of 10 mm was used in the short-axis rubber extruder 100 shown in FIG. 2 A sheet with a thickness of 10 mm aligned with the first thermally conductive filler (scaly boron nitride) in the thickness direction was produced, and the sheet was subjected to crosslinking treatment at 170 ° C for 30 minutes. The sheet after the cross-linking treatment was sliced perpendicularly to the thickness direction to produce a thermally conductive sheet 1 as a thermally conductive resin molded article having a thickness of 500 μm.

(Example 2) A thermally conductive sheet 1 was produced in the same manner as in Example 1 except that the amount of raw material components was changed as shown in Table 1.

(Example 3) A filler containing magnesium carbonate (cubic shape, particle size 15 μm, aspect ratio of about 1 (manufactured by Jindao Chemical Industry Co., Ltd.)) was used except for the second thermally conductive filler, and the raw materials were changed as shown in Table 1. The heat conductive sheet 1 was produced like Example 1 except the compounding quantity of a component.

(Example 4) A thermally conductive sheet 1 was produced in the same manner as in Example 1 except that the amount of raw material components was changed as shown in Table 1.

(Example 5) In addition to the second thermally conductive filler, a filler containing magnesium oxide (“SMO” (spherical, particle size 10 μm, aspect ratio about 1) manufactured by Sakai Chemical Industry Co., Ltd.) was used. A heat conductive sheet 1 was produced in the same manner as in Example 1, except that the amount of the raw material components was changed as usual.

(Example 6) A thermally conductive sheet 1 was produced in the same manner as in Example 5 except that the blending amount of raw material components was changed as shown in Table 1.

(Example 7) Except for the second thermally conductive filler, a filler containing magnesium carbonate (cubic shape, particle size of 26 μm, aspect ratio of about 1 (manufactured by Jindao Chemical Industry Co., Ltd.)) was used, and the raw materials were changed as shown in Table 1. The heat conductive sheet 1 was produced like Example 1 except the compounding quantity of a component.

(Example 8) A thermally conductive sheet 1 was produced in the same manner as in Example 3, except for changing the blending amount of raw material components as shown in Table 1.

(Example 9) A thermally conductive sheet 1 was produced in the same manner as in Example 1 except that the amount of raw material components was changed as shown in Table 1.

(Example 10) Except for the use of a filler containing calcium carbonate (“light calcium carbonate” manufactured by Maruo Calcium Co., Ltd. (spherical, particle size 6 μm, aspect ratio about 1)) as the second thermally conductive filler, Example 7 The thermally conductive sheet 1 was produced in the same manner.

(Example 11) Except that the second thermally conductive filler uses a filler containing magnesium oxide ("Stamag MSL" (spherical, particle size 9 μm, aspect ratio 1) manufactured by Shendao Chemical Industry Co., Ltd.), and In Example 7, the thermally conductive sheet 1 was produced in the same manner.

(Comparative Example 1 and Comparative Example 2) A thermally conductive sheet 1 was produced in the same manner as in Example 1 except that the amount of raw material components was changed as shown in Table 1 (the second thermally conductive filler was not used).

[Evaluation Test] (1) Hardness As the hardness of the obtained thermally conductive resin sheet, Asker C hardness was measured. The results are shown in Table 1. (2) Thermal resistance Using a TIM TESTER 1300, the thermal resistance in the thickness direction of the obtained thermally conductive resin sheet was measured at three levels of measurement pressure (0.1 MPa, 0.3 MPa, and 0.5 MPa). Table 1 shows the measured values. In addition, the determination was made by the steady-state method and according to the American Standard for American Society for Testing and Materials (ASTM) D5470. The results are shown in Table 1.

[Table 1]

As is clear from the results shown in Table 1, according to the embodiments of the present invention, it is possible to provide a thermally conductive resin sheet that reduces the amount of expensive BN used and has a low thermal resistance value.

1‧‧‧ Thermally conductive sheet

2‧‧‧ matrix composition

4‧‧‧The first thermally conductive filler

5‧‧‧Second thermally conductive filler

6‧‧‧Fusion wire

8‧‧‧screw

10‧‧‧Flow

12‧‧‧ First gap

14‧‧‧ 2nd gap

100‧‧‧Extruder

FIG. 1 is a cross-sectional view schematically showing a thermally conductive sheet according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing an extruder used in the production of a thermally conductive sheet according to an embodiment of the present invention.

Claims (3)

A thermally conductive resin molded article comprising a resin and a thermally conductive filler, the thermally conductive filler including a first thermally conductive filler and a second thermally conductive filler having a smaller particle size than the first thermally conductive filler, the thermal conductivity The resin molded article is characterized in that the content of the thermally conductive filler is 30% by volume to 50% by volume, and the first thermally conductive filler is boron nitride containing a particle diameter of 30 μm or more and an aspect ratio of 10 or more. The filler, the content of the first thermally conductive filler is 5 to 20% by volume, and the second thermally conductive filler is a filler containing materials other than boron nitride. The thermally conductive resin molded article as described in item 1 of the patent application range, wherein the particle diameter of the second thermally conductive filler is 3 μm to 20 μm. The thermally conductive resin molded article according to item 1 or 2 of the patent application range, wherein the second thermally conductive filler is a filler containing magnesium oxide or magnesium carbonate.