JP2010285569A - Thermoconductive resin material and production method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoconductive resin material having high heat conductivity and easy to process, using a composite material provided by filling thermoconductive particles in an organic polymer resin at a high density without flocculation. <P>SOLUTION: As for the thermoconductive resin material 1 provided by filling the thermoconductive particles in the organic polymer resin 5, the thermoconductive particles are mixed particles 4 having different particle diameter distribution, the mixed particles 4 are composed of crude particles 2 having an average particle diameter of ≥100 μm but ≤500 μm and fine particles 3 having an average particle diameter less than that of the crude particles 2, and the ratio of the average particle diameter of the crude particles 2 to that of the fine particles 3 is ≥30/1 but ≤180/1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermally conductive resin material obtained by combining high thermal conductivity particles in an organic material and a method for producing the same.

  Conventionally, high thermal conductivity metals such as copper, aluminum, and magnesium are generally used as materials having thermal conductivity for heat dissipation. However, since metal has conductivity, the usable range is limited from the viewpoint of ensuring electrical insulation. For example, since it is necessary to maintain insulation between wirings in an electronic circuit board such as a computer, the use of metal as a heat radiating member is limited.

  On the other hand, ceramic materials such as alumina, aluminum nitride, and boron nitride are examples of materials having electrical insulation and thermal conductivity other than metal. However, because these materials are hard solids and have a very high melting point of 2000 ° C. or higher, it is difficult to perform press molding or injection molding, and therefore there are limitations on processing into arbitrary shapes.

  In addition, in electronic devices that are required to be reduced in size and weight, a space for installing a heat sink for heat dissipation is also extremely small, and a heat conductive material that can be processed into any shape according to the shape of a circuit board or other electronic components is required. .

  In recent years, fine particle composites that combine the unique physical properties of fine particles with the flexible and easy processability of organic polymer resins by mixing inorganic fine particles into organic polymers (base materials) such as resins. The technology of synthetic resin materials has attracted attention. For example, by mixing ceramic particles having a high thermal conductivity such as alumina into an organic polymer resin to form a composite, a resin material having a low thermal conductivity can be used as a resin material having a high thermal conductivity. Such a composite resin material has a low melting point, and can be easily processed by injection at a low temperature of about 100 ° C. to 200 ° C., molding by press molding, or molding into a film.

  On the other hand, in order to use such a composite resin material as a heat dissipation member, it is necessary to increase the thermal conductivity of the composite resin material by filling the resin material with inorganic fine particles at a high density. .

  As such a resin material, Patent Document 1 discloses a heat conductive resin material in which an alumina powder having a frequency peak in a particle size distribution region of at least 0.2 to 2 μm and 2 to 63 μm is blended with a resin.

  Further, the resin contains an inorganic powder composed of boron nitride powder having an average particle diameter of 100 to 300 μm and spherical alumina powder having an average particle diameter of 1 to 10 μm, containing 90% by mass or more of particles having a particle diameter of 50 to 350 μm. A thermally conductive resin material disclosed in Patent Document 2 is disclosed.

JP-A-2005-306718 JP 2005-343983 A

  As described above, in order to increase the thermal conductivity of the fine particle composite resin material in which the thermal conductive inorganic particles are mixed in the organic polymer resin, the inorganic fine particles having high thermal conductivity are added at a high density in the resin material. It is important to fill. Therefore, as described in Patent Document 1, a method is used in which particles having a plurality of particle size peaks are used, gaps between large particles are filled with small particles, and the particles are filled with high density.

  However, particles such as alumina and aluminum nitride have a characteristic that single particles tend to aggregate. In particular, when the particle diameter is smaller than 2 μm, the aggregation becomes remarkable, and there is a problem that the packing density of the particles in the resin material becomes insufficient without uniformly mixing the large particles and the small particles.

  If the packing density of the particles is insufficient, the thermal conductivity of the resin material becomes small, making it difficult to apply as a heat dissipation member for a circuit board that generates heat. Further, when the heat generation amount of the heat generating member is large, the temperature of the resin material rises, and there is a problem that the resin material itself is melted.

  The present invention has been made to solve these problems. By filling inorganic polymer particles in an organic polymer resin with high density, the present invention has high thermal conductivity and is easy to process, and can be used for heat sinks and heat dissipation. It aims at providing the heat conductive resin material suitable for uses, such as a housing | casing, and its manufacturing method.

  In order to achieve the above object, the thermally conductive resin material of the present invention is a thermally conductive resin material composed of a composite material in which thermally conductive particles are filled with an organic polymer resin, and the thermally conductive particles have a particle size of Mixed particles having different distributions, and the mixed particles are composed of first particles having an average particle diameter of 100 μm or more and 500 μm or less, and second particles having an average particle diameter smaller than the first particles, and the average of the first particles The ratio of the particle diameter to the average particle diameter of the second particles is 30: 1 or more and 180: 1 or less.

  According to such a configuration, the second particles can be filled at a high density between the first particles having a large particle diameter, and the packing density of the mixed particles in the resin material can be increased to increase the heat conduction of the resin material. The rate can be increased.

  Furthermore, the volume ratio of the second particles in the total volume of the mixed particles is preferably 20% by volume or more and 50% by volume or less. According to such a configuration, it is possible to further increase the filling rate of the inorganic particles and realize a resin material with higher thermal conductivity.

  Furthermore, it is desirable that the average particle diameter of the second particles is 2 μm or more. According to such a configuration, it is possible to suppress the aggregation of the second particles and to fill the second particles at a high density with the gap between the adjacent first particles to realize a higher thermal conductivity.

  Furthermore, the conductive particles are preferably aluminum nitride particles or silicon carbide particles. According to such a configuration, a resin material having high thermal conductivity can be realized.

  Furthermore, it is preferable that the first particles are silicon carbide particles and the second particles are aluminum nitride particles. According to such a configuration, it is possible to realize a resin material having a higher thermal conductivity.

  Moreover, the manufacturing method of the heat conductive resin material of this invention is the average of 1/180 or more and 1/30 or less with respect to the 1st particle | grains which have an average particle diameter of 100 micrometers or more and 500 micrometers or less, and the average particle diameter of 1st particle | grains. A step of preparing mixed particles with second particles having a particle size, a step of preparing a composite resin material by adding and mixing the mixed particles to a heated and melted organic polymer resin, and a composite resin material in a predetermined shape A processing step.

  According to such a method, it is possible to easily realize a thermally conductive resin material having high thermal conductivity by being mixed with high density mixed particles having high thermal conductivity and having excellent moldability. .

  Moreover, the manufacturing method of the heat conductive resin material of this invention is the average of 1/180 or more and 1/30 or less with respect to the 1st particle | grains which have an average particle diameter of 100 micrometers or more and 500 micrometers or less, and the average particle diameter of 1st particle | grains. A step of dispersing a second particle having a particle size in a solvent liquid to prepare a mixed particle dispersion solvent liquid, a step of adding a mixed particle dispersion solvent liquid to an organic polymer resin and preparing a composite resin material, And a step of processing the composite resin material into a predetermined shape.

  According to such a method, it is possible to easily realize a thermally conductive resin material having high thermal conductivity by being mixed with high density mixed particles having high thermal conductivity and having excellent moldability. .

  Furthermore, the solvent liquid can dissolve the organic polymer resin, and after the mixed particle dispersion solvent liquid containing the solvent liquid is added to and mixed with the organic polymer resin, the solvent liquid is volatilized and scattered by a solvent distillation method to form a composite resin. Materials may be prepared. According to such a method, it is possible to realize a composite resin material that can more reliably disperse mixed particles and has no solvent remaining.

  Furthermore, it is desirable that the solvent liquid contains one or more of toluene, xylene, cyclohexane, and ethanol. According to such a method, it is possible to disperse the inorganic particles having a small particle size in the solvent liquid while suppressing aggregation, and it is possible to fill the inorganic particles having a small particle size between the inorganic particles having a large particle size. It becomes.

  Furthermore, it is desirable that the first particles and the second particles are aluminum nitride particles or silicon carbide particles. According to such a method, a resin material having a higher thermal conductivity can be realized.

  As described above, according to the thermally conductive resin material and the manufacturing method thereof of the present invention, it is possible to realize a resin material filled with high density in an organic polymer resin by suppressing aggregation of inorganic particles. A heat conductive resin material suitable for a heat radiating member having conductivity can be realized.

It is the schematic which shows the structure of the heat conductive resin material in Embodiment 1 of this invention. It is a flowchart which shows the manufacturing method of the heat conductive resin material. It is a figure which shows the particle size distribution of the coarse particle of the aluminum nitride used for the heat conductive resin material. It is a figure which shows the particle size distribution of the aluminum nitride microparticles | fine-particles used for the heat conductive resin material. It is a figure which shows the relationship between the fine particle mixing rate of the aluminum nitride particle in the same heat conductive resin material, and the packing density of mixed particles. It is a figure which shows the relationship between the particle diameter ratio of the coarse particle of aluminum nitride particle used for the heat conductive resin material, and microparticles | fine-particles, and the maximum packing density. It is a figure which shows the relationship between the particle diameter of the coarse particle of the aluminum nitride particle used for the heat conductive resin material, and the maximum packing density. It is a figure which shows the heat conductivity of the heat conductive resin material. It is the schematic which shows the structure of the heat conductive resin material in Embodiment 2 of this invention. It is a figure which shows the particle size distribution of the coarse particle of the silicon carbide used for the heat conductive resin material. It is a figure which shows the particle size distribution of the aluminum nitride microparticles | fine-particles used for the heat conductive resin material. It is a figure which shows the heat conductivity of the heat conductive resin material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The heat conductive resin material in Embodiment 1 of this invention is demonstrated using FIGS.

  FIG. 1 is a schematic diagram showing a configuration of a thermally conductive resin material in Embodiment 1 of the present invention, FIG. 2 is a flowchart showing a method for producing the thermally conductive resin material, and FIG. 3A is used for the thermally conductive resin material. FIG. 3B is a diagram showing the particle size distribution of aluminum nitride (AlN) coarse particles, FIG. 3B is a diagram showing the particle size distribution of aluminum nitride (AlN) particles used in the thermally conductive resin material, and FIG. 4 is the thermally conductive resin. The figure which shows the relationship between the fine particle mixing rate of the aluminum nitride (AlN) particle | grains in material, and the packing density of mixed particle | grains, FIG. 5 is the coarse particle of the aluminum nitride (AlN) particle | grain used for the heat conductive resin material, and the particle diameter of fine particle FIG. 6 is a diagram showing the relationship between the ratio and the maximum packing density, FIG. 6 is a diagram showing the relationship between the coarse particle size of the aluminum nitride (AlN) particles used in the thermally conductive resin material and the maximum packing density, and FIG. Thermal conductivity Is a diagram showing the thermal conductivity of the fat materials.

  As shown in FIG. 1, the thermally conductive resin material 1 in Embodiment 1 of the present invention has aluminum nitride (AlN) as second particles in the gaps between coarse particles 2 of aluminum nitride (AlN) as first particles. The mixed particles 4 filled with the fine particles 3) are filled in the organic polymer resin 5 and formed.

  That is, the bulk density of the aluminum nitride (AlN) particles is increased so that the gaps between the adjacent coarse particles 2 are filled with the fine particles 3, and the packing density of the aluminum nitride (AlN) particles in the organic polymer resin 5 is increased. Try to increase. As a result, the proportion of thermally conductive aluminum nitride (AlN) particles in the thermally conductive resin material 1 is increased, the thermal conductivity of the thermally conductive resin material 1 can be increased, and heat dissipation is easy. It becomes possible to realize the thermally conductive resin material 1 that can be used as a member.

  Hereinafter, the manufacturing method of the heat conductive resin material 1 in Embodiment 1 of this invention is demonstrated in detail using the flowchart shown in FIG.

  First, 60 g of aluminum nitride (AlN) coarse particles 2 having an average particle size of 300 μm having the particle size distribution shown in FIG. 3A and aluminum nitride having an average particle size of 5 μm having a particle size distribution shown in FIG. 3B ( 40 g of fine particles 3 of AlN) are weighed and prepared (steps S101 and S102).

  Thereafter, both are mixed to prepare 100 g of mixed particles 4 of aluminum nitride (AlN) in which the ratio of the fine particles 3 to the entire particles is 40% by weight (step S103).

  Subsequently, 12 g of an organic polymer resin 5 having a softening point of 90 ° C. and a specific gravity of 0.92 is prepared, and heated and melted at a temperature of 190 ° C. to prepare a molten organic polymer resin (step S104).

  100 g of the above-mentioned mixed particles 4 of aluminum nitride (AlN) is added to the molten organic polymer resin, and a mixture of the organic polymer resin 5 and the aluminum nitride particles of the mixed particles 4 composed of the coarse particles 2 and the fine particles 3 is added. Make and stir the mixture for 30 minutes at a temperature of 190 ° C. In this process, a molten mixture in which the mixed particles 4 are uniformly mixed with the organic polymer resin 5 is prepared. Next, this molten mixture is cooled to a temperature of 50 ° C. or lower and solidified. In this way, 100 g of mixed particles 4 of aluminum nitride (AlN) particles composed of coarse particles 2 having an average particle diameter of 300 μm and fine particles 3 having an average particle diameter of 5 μm are uniformly distributed within 12 g of organic polymer resin 5. The thermally conductive resin material 1 distributed in the above is produced (step S105). The packing density of the mixed particles 4 in the thermally conductive resin material 1 produced here is 89% by weight in terms of weight percentage, and 70% by volume in terms of volume percentage.

  As described above, when the mixed particles 4 having different particle size distributions are mixed with the organic polymer resin 5 and the fine particles 3 are filled in the gaps of the coarse particles 2, the mixed particles 4 are densely packed in the organic polymer resin 5. It becomes possible to fill, and the heat conductive resin material 1 with high heat conductivity can be produced.

  In particular, in Embodiment 1 of the present invention, the mixed particles 4 are coarse particles 2 that are first particles having an average particle diameter of 100 μm or more and 500 μm or less, and second particles that are smaller in average particle diameter than the first particles. The ratio of the average particle diameter of the coarse particles 2 to the average particle diameter of the fine particles 3 is 30: 1 or more and 180: 1 or less. As a result, the aggregation of the fine particles 3 when preparing the mixed particles 4 is suppressed, and the fine particles 3 can be filled in the gaps between the adjacent coarse particles 2 with high density.

  Next, the heat conductive resin material 1 is processed into a heat radiating member or the like by, for example, injection molding or press molding (step S106).

  FIG. 4 shows the filling rate (volume%) of the mixed particles 4 in the thermally conductive resin material 1 with respect to the fine particle mixing ratio (volume%) which is the ratio of the fine particles 3 in the mixed particles 4 of aluminum nitride (AlN). The particle size ratio between the coarse particles 2 and the fine particles 3 (coarse particle average particle size / fine particle average particle size) is shown as a parameter.

  From FIG. 4, for example, in the mixed particle 4 in which the average particle diameter of the coarse particles 2 is 300 μm, the average particle diameter of the fine particles 3 is 5 μm, and the particle diameter ratio is 60, the fine particle 3 mixing ratio is 40% by volume. A maximum packing density of 77% by volume is obtained. Further, in the mixed particles 4 in which the average particle size of the coarse particles 2 is 300 μm, the average particle size of the fine particles 3 is 30 μm, and the particle size ratio is 10, the maximum packing density is 70% by volume when the fine particle mixing rate is 30% by volume. can get. Furthermore, in the mixed particles 4 in which the average particle diameter of the coarse particles 2 is 300 μm, the average particle diameter of the fine particles 3 is 3 μm, and the particle diameter ratio is 100, the maximum packing density is 79 volume% when the fine particle mixing ratio is 40 volume%. can get.

  From the results shown in FIG. 4, the mixing ratio of the fine particles 3 having the maximum filling rate is in the range of 20% by volume or more and 50% by volume or less in the mixed particles 4 having any particle size ratio of the coarse particles 2 and the fine particles 3. Therefore, by setting the mixing ratio of the fine particles 3 within this range, the filling rate of the heat conductive particles into the heat conductive resin material 1 can be increased, and the heat conductivity having a higher heat conductivity can be achieved. The resin material 1 can be realized.

  Further, in FIG. 5, heat conductive resin material 1 in which coarse particles 2 of aluminum nitride (AlN) having an average particle diameter of 300 μm are used as the first particles and the mixing ratio of fine particles 3 in mixed particles 4 is 40 volume%. 2 shows the relationship between the particle size ratio between the coarse particles 2 and the fine particles 3 (coarse particle average particle size / fine particle average particle size) and the maximum packing density.

  FIG. 5 shows that when the particle size ratio between the coarse particles 2 and the fine particles 3 is 30 or less, the maximum packing density rapidly decreases. This is because if the particle diameter of the fine particles 3 becomes large or the particle diameter of the coarse particles 2 becomes small, the gaps between the coarse particles 2 cannot be filled with the fine particles 3.

  Further, even when the particle size ratio is 150 or more, the maximum packing density is lowered, and in particular, the particle size ratio is reduced to 180 or more. This is because when the particle size ratio is 150 or more, that is, when the average particle size of the fine particles 3 is 2 μm or less, the fine particles 3 aggregate and the coarse particles 2 and the fine particles 3 are not mixed uniformly.

  Therefore, the average particle diameter of the fine particles 3 in the mixed particles 4 is desirably at least 2 μm, and the particle diameter ratio between the coarse particles 2 and the fine particles 3 is 30 or more and 180 or less, preferably 50 or more and 150 or less. For example, the mixed particles 4 can be filled in the heat conductive resin material 1 at a high density.

  In the above description, the average particle diameter of the aluminum nitride (AlN) coarse particles 2 is set to 300 μm, but the packing density varies depending on the average particle diameter of the coarse particles 2.

  FIG. 6 shows the average particle size of the coarse particles 2 in the thermally conductive resin material 1 in which the particle diameter ratio between the coarse particles 2 and the fine particles 3 is 50 and the mixing ratio of the fine particles 3 in the mixed particles 4 is 40% by weight. The change of the maximum packing density when the diameter is changed is shown.

  FIG. 6 shows that the maximum packing density decreases when the average particle diameter of the coarse particles 2 is 100 μm or less. As described above, when the particle size ratio is 50 and the average particle size of the coarse particles 2 is 100 μm, the particle size of the fine particles 3 is 2 μm or less, and the fine particles 3 are aggregated and uniformly mixed with the coarse particles 2. This is because it disappears.

  On the other hand, when the average particle diameter of the coarse particles 2 is 500 μm or more, the coarse particles 2 of aluminum nitride (AlN) are exposed on the surface of the heat conductive resin material 1 to generate irregularities.

  The occurrence of such irregularities reduces the adhesion of the surface of the heat conductive resin material 1, and thus reduces the heat conductivity between the heat generating member and the heat conductive resin material 1. Therefore, the average particle diameter of the aluminum nitride coarse particles 2 is preferably 500 μm or less.

  Therefore, in order to improve the packing density of the particles and maintain the adhesion of the heat conductive resin material, the average particle diameter of the aluminum nitride (AlN) coarse particles 2 is 100 μm or more and 500 μm or less, and the coarse particles 2 and the fine particles The particle size ratio with respect to 3 is preferably 30 or more and 180 or less.

  Next, the heat conductivity of the heat conductive resin material 1 in Embodiment 1 of this invention is demonstrated using FIG.

  Here, as a sample piece for measuring the thermal conductivity of the thermal conductive resin material 1, the thermal conductive resin material 1 manufactured based on the above-described manufacturing method is heated to a temperature of 180 ° C. and melted again, and press molding is performed. Is used to prepare a sample that is processed into a disk shape having a diameter of 10 mm and a thickness of 3 mm, and then cooled and solidified to form a disk shape.

  FIG. 7 shows the result of measurement of the thermal conductivity of this sample piece by the laser flash method. In the case where the sample is made of aluminum nitride particles having only coarse particles as a comparative example, the thermal conductivity of only an organic polymer resin is also used as a comparative example. The result of measuring the rate is shown.

  In FIG. 7, sample A is a heat conductive resin material according to Embodiment 1 of the present invention, that is, coarse particles 2 having an average particle diameter of 300 μm and fine particles 3 having an average particle diameter of 5 μm are mixed at a packing density of 40% by volume. The thermal conductivity of the thermally conductive resin material 1 using aluminum nitride (AlN) particles is shown. Sample B shows the thermal conductivity when only the aluminum nitride particles having an average particle diameter of 300 μm shown in FIG. 3A are used (packing density 40 vol%), and sample C is only organic polymer resin. The thermal conductivity of is shown.

  From FIG. 7, the thermal conductivity of sample A is 8.2 W / m · K, which is about four times the thermal conductivity of sample B as a comparative example, 1.9 W / m · K. It can be seen that the conductivity is improved by about 20 times compared to 0.4 W / m · K.

  As described above, according to the present embodiment, the aggregation of the aluminum nitride (AlN) fine particles 3 is prevented, and the fine particles 3 and the coarse particles 2 are uniformly mixed, so that the gaps between the coarse particles 2 are reduced. It becomes possible to fill the fine particles 3 with high density. As a result, the maximum packing density that can be filled into the heat conductive resin material 1 is increased, the contact area between the heat conductive particles in the heat conductive resin material 1 is increased, and the heat conductive resin material 1 is high. It becomes possible to realize thermal conductivity.

  In the description of Embodiment 1 of the present invention, aluminum nitride (AlN) particles are used as thermally conductive particles, but silicon carbide (SiC) particles may be used instead of aluminum nitride (AlN). Similar effects can be obtained.

(Embodiment 2)
The heat conductive resin material in Embodiment 2 of this invention is demonstrated using FIGS. 8-10.

  FIG. 8 is a schematic diagram showing the configuration of the thermally conductive resin material in Embodiment 2 of the present invention, FIG. 9A is a diagram showing the particle size distribution of coarse particles of silicon carbide (SiC) used in the thermally conductive resin material, FIG. 9B is a view showing the particle size distribution of aluminum nitride (AlN) fine particles used for the thermally conductive resin material, and FIG. 10 is a view showing the thermal conductivity of the thermally conductive resin material.

  As shown in FIG. 8, the thermally conductive resin material 10 in Embodiment 2 of the present invention uses silicon carbide (SiC) as the coarse particles 6 that are the first particles, and aluminum nitride as the fine particles 7 that are the second particles. (AlN) is used. Mixed particles 8 in which fine particles 7 of aluminum nitride (AlN) are filled in gaps between coarse particles 6 of silicon carbide (SiC) are filled in an organic polymer resin 9.

  When the aluminum nitride (AlN) fine particles 7 enter the gaps between the silicon carbide (SiC) coarse particles 6, the bulk density of the mixed particles 8 of thermally conductive particles made of silicon carbide (SiC) and aluminum nitride (AlN) is reduced. It increases, and it becomes possible to increase the filling density to the organic polymer resin 9. As a result, the proportion of the thermally conductive mixed particles 8 in the thermally conductive resin material 10 increases, the thermal conductivity of the thermally conductive resin material 10 can be increased, and it can be used as a heat radiating member that can be easily molded. It is possible to realize a heat conductive resin material 10 that is stable.

  Since the manufacturing method of the heat conductive resin material 10 in Embodiment 2 of this invention is fundamentally the same as the manufacturing method of the heat conductive resin material 1 in Embodiment 1 of this invention, it shows in FIG. The manufacturing method will be described in detail using a flowchart.

First, 60 g (corresponding to a volume of 18.6 cm ³ ) of silicon carbide (SiC) coarse particles 6 having a particle size distribution as shown in FIG. 9A and an average particle size of 300 μm, and the particle size distribution shown in FIG. 40 g (corresponding to a volume of 12.3 cm ³ ) of the aluminum nitride (AlN) fine particles 7 having an average particle diameter of 5 μm are weighed and prepared (steps S101 and S102). Thereafter, both are mixed to prepare 100 g (corresponding to a volume of 30.9 cm ³ ) of mixed particles 8 in which the volume ratio of aluminum nitride (AlN) fine particles 7 occupying the whole is 40 volume% (step S103).

Subsequently, 12 g (corresponding to a volume of 13.0 cm ³ ) of the organic polymer resin 9 having a softening point of 90 ° C. and a specific gravity of 0.92 is heated and melted at a temperature of 190 ° C. to prepare a molten organic polymer resin (step S104).

  100 g of the mixed particles 8 are added to the molten organic polymer resin, the organic polymer resin and the mixed particles 8 are mixed, and stirred at a temperature of 190 ° C. for about 30 minutes.

  By this step, a molten mixture of organic polymer resin 9 in which mixed particles 8 of coarse particles 6 of silicon carbide (SiC) and fine particles 7 of aluminum nitride (AlN) are uniformly mixed is prepared.

  Next, this molten mixture is cooled to a temperature of 50 ° C. or lower and solidified.

  Thus, 100 g of the mixed particles 8 in which the coarse particles 6 of silicon carbide (SiC) having an average particle diameter of 300 μm and the fine particles 7 of aluminum nitride (AlN) having an average particle diameter of 5 μm are mixed together are organic polymer resins. 9 can be produced (step S105).

  At this time, the packing density of the mixed particles 8 in the produced thermally conductive resin material 10 is 89% by weight in terms of weight percentage, and 70% by volume in terms of volume percentage.

  In particular, in Embodiment 2 of the present invention, the mixed particles 8 are composed of coarse particles 6 having an average particle diameter of 100 μm or more and 500 μm or less, and fine particles 7 having an average particle diameter smaller than the coarse particles 6, and the coarse particles The ratio of the average particle size of 6 to the average particle size of the fine particles 7 is set to be 30: 1 or more and 180: 1 or less. As a result, the aggregation of the fine particles 7 when the mixed particles 8 are prepared is suppressed, and the fine particles 7 can be filled in the gaps between the adjacent coarse particles 6 with high density.

  Next, the heat conductive resin material 10 is processed into a heat radiating member or the like by, for example, injection molding or press molding (step S106).

  In the heat conductive resin material 10 in the above-described second embodiment, silicon carbide (SiC) having a higher thermal conductivity than aluminum nitride (AlN) is used as the coarse particles 6 of the heat conductive particles. Compared with the case of only the aluminum nitride (AlN) particles described in 1, the thermal conductivity can be further increased.

  Generally, since silicon carbide (SiC) has high hardness, it is difficult to grind to a particle size of 10 μm or less. For this reason, in Embodiment 2 of the present invention, high density filling is realized by mixing coarse particles 6 and fine particles 7 by using aluminum nitride (AlN) for fine particles 7.

  Next, the thermal conductivity of the thermally conductive resin material 10 produced in Embodiment 2 of the present invention will be described with reference to FIG.

  Here, as a sample piece for measuring the thermal conductivity of the thermally conductive resin material 10, the thermally conductive resin material 10 manufactured based on the above-described manufacturing method is heated to 180 ° C. and melted again, and press molding is performed. The sample which was processed into a disk shape with a diameter of 10 mm and a thickness of 3 mm, and then cooled and solidified to form a disk shape is used.

  In FIG. 10, the result of measuring the thermal conductivity of the sample piece in Embodiment 2 of the present invention by the laser flash method is shown as Sample D, and as a comparative example, mixed particles of only the aluminum nitride (AlN) of Embodiment 1 The thermal conductivity of the thermally conductive resin material using the sample is the sample E, and the thermal conductivity of the thermally conductive resin material using only coarse particles of silicon carbide (SiC) having an average particle diameter of 300 μm as the comparative example is the sample F. Show.

  From FIG. 10, the heat conductive resin material 10 in the second embodiment of the present invention has a thermal conductivity of 11.2 W / m · K, and the heat conductive resin material 1 in the first embodiment as a comparative example. Compared to the thermal conductivity of 8.2 W / m · K, it is improved about 1.3 times. In addition, it can be seen that the thermal conductivity of the silicon resin (SiC) particles having an average particle diameter of 300 μm alone is improved by about 5 times compared with the thermal conductivity of 2.2 W / m · K.

  As described above, even when mixing fine particles and coarse particles of different materials as in Embodiment 2 of the present invention, the fine particles are filled in the gaps between the coarse particles and filled into the thermally conductive resin material. It is possible to increase the density, increase the contact area between the particles in the heat conductive resin material, and improve the thermal conductivity.

  In the first and second embodiments described above, in accordance with the flowchart of the manufacturing method shown in FIG. 2, aluminum nitride or silicon carbide particles are added and mixed into the molten organic polymer resin to produce a heat conductive resin material. An example was given. However, the manufacturing method of a heat conductive resin material is not limited to said method.

  For example, a solvent dispersion in which thermally conductive particles having different particle size distributions are dispersed in a solvent capable of dissolving the organic polymer resin is added and formulated, and the solvent dispersion is added to the organic polymer resin to form an organic polymer. A method of distilling off the solvent after dissolving the resin and mixing the organic polymer resin and the thermally conductive particles is also possible.

  At this time, toluene, xylene, cyclohexane, ethanol, or the like can be used as the organic solvent, and these solvents may be used alone or in combination.

  In addition, when using a solvent that does not dissolve the organic polymer resin, add the mixed dispersion solvent liquid of thermally conductive particles dropwise into the heated and melted organic polymer resin, and stir in the molten state to conduct heat with the organic polymer resin. By mixing the conductive particles, a composite heat-dissipating resin material in which mixed particles having different particle size distributions are uniformly distributed can be produced.

  As described above, the thermally conductive resin material and the manufacturing method thereof according to the present invention realizes a thermally conductive resin material having high thermal conductivity that can be applied to an electronic device or an electric circuit that requires heat dissipation, and injection molding. Therefore, it can be used for various shapes of heat sinks, heat radiating members, and the like.

1,10 Thermally conductive resin material 2,6 Coarse particles 3,7 Fine particles 4,8 Mixed particles 5,9 Organic polymer resin

Claims (11)

A thermally conductive resin material in which thermally conductive particles are filled in an organic polymer resin,
The thermally conductive particles are mixed particles having different particle size distributions. The mixed particles include first particles having an average particle size of 100 μm or more and 500 μm or less, and second particles having an average particle size smaller than that of the first particles. And a ratio of the average particle diameter of the first particles to the average particle diameter of the second particles is 30: 1 or more and 180: 1 or less. 2. The thermally conductive resin material according to claim 1, wherein the volume of the second particles is 20 volume% or more and 50 volume% or less with respect to the volume of all the particles of the mixed particles. The heat conductive resin material according to claim 1 or 2, wherein an average particle diameter of the second particles is 2 µm or more. The thermally conductive resin material according to any one of claims 1 to 3, wherein the thermally conductive particles are aluminum nitride particles or silicon carbide particles. The thermally conductive resin material according to any one of claims 1 to 4, wherein the first particles are silicon carbide particles, and the second particles are aluminum nitride particles. A mixed particle of first particles having an average particle diameter of 100 μm or more and 500 μm or less and second particles having an average particle diameter of 1/180 or more and 1/30 or less with respect to the average particle diameter of the first particles is prepared. Process,
A step of preparing a composite resin material by adding and mixing the mixed particles to a heated and melted organic polymer resin; and
And a step of processing the composite resin material into a predetermined shape. First particles having an average particle diameter of 100 μm or more and 500 μm or less and second particles having an average particle diameter of 1/180 or more and 1/30 or less of the average particle diameter of the first particles are dispersed in a solvent liquid. Preparing a mixed particle dispersion solvent liquid,
A step of preparing a composite resin material by adding and mixing the mixed particle dispersion solvent liquid to an organic polymer resin; and
And a step of processing the composite resin material into a predetermined shape. The solvent liquid can dissolve the organic polymer resin, and after the mixed particle dispersion solvent liquid containing the solvent liquid is added to and mixed with the organic polymer resin, the solvent liquid is volatilized and scattered by a solvent distillation method. The method for producing a thermally conductive resin material according to claim 7, wherein the composite resin material is prepared. The method for producing a thermally conductive resin material according to claim 7, wherein the mixed resin material is prepared by adding the mixed particle-dispersed solvent liquid to the heat-melted organic polymer resin and stirring and mixing the mixture. The method for producing a thermally conductive resin material according to claim 8, wherein the solvent liquid contains one or more of toluene, xylene, cyclohexane, and ethanol. The method for producing a thermally conductive resin material according to any one of claims 6 to 10, wherein the first particles and the second particles are aluminum nitride particles or silicon carbide particles.

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