Mixed particle material, filler material, slurry composition, and resin composition

Abstract

The present invention addresses the problem of providing a mixed particle material, a filler material, and a slurry composition with which it is possible to form a resin composition having high fluidity, and a resin composition having high fluidity. A mixed particle material according to the present invention is formed of a mixture comprising: an alumina particle material that has a mode diameter exhibiting a maximum value A at 3-12 µm; and a silica particle material that has a particle diameter of 10-100 nm and that is contained in an amount of 0.1-4% based on the mass of the alumina particle material.

Description

Mixed particle material, filler material, slurry composition and resin composition

[0001] The present invention relates to a mixed particle material, a filler material, and a slurry composition that can constitute a highly fluid resin composition, and to a highly fluid resin composition.

[0002] Examples of thermally conductive materials such as TIM that constitute the component interposed between the heating element and the heat dissipation member include resin compositions in which alumina particles, which have high thermal conductivity, are dispersed in a resin material. High fluidity is desirable for the TIM to improve adhesion to the heating element and other components.

[0003] Conventionally, a technique has been disclosed in which silica with a nanometer-order particle size and a hydrophobic surface is blended with the alumina particle material to improve its fluidity in a dry state (Patent Document 1).

[0004] Patent No. 6771078

[0005] As explained above, it is required that a resin composition in which alumina particle material is dispersed in a resin material be able to achieve both fluidity and thermal conductivity.

[0006] The problem to be solved by the present invention is to provide a mixed particle material, a filler material, and a slurry composition that can constitute a resin composition with high fluidity, as well as a resin composition with high fluidity.

[0007] In order to solve the above problems, the present inventors conducted diligent studies and have completed the following invention. (1) That is, the mixed particle material of the present invention that solves the above problems consists of a mixture of an alumina particle material having a peak in the range A of 3 μm or more and 12 μm or less, and a silica particle material having a content of 0.1% or more and 4% or less based on the mass of the alumina particle material, and a particle size of 10 nm or more and 100 nm or less.

[0008] The mixed particle material described in (1) above can be combined with one or more of the items described in (2) to (4) and (6) below. When combining item (4), item (5) can be further combined, and when combining item (6), item (7) can be further combined. (2) The specific surface area of ​​the alumina particle material is 0.2 to 20 m². ２ (1) The amount is / g. (3) The alumina particle material has a peak in range B of 0.1 μm to 1.5 μm, and (area of ​​range A) / (area of ​​range B) is 0.5 to 10. (4) The alumina particle material has a peak in range C of 1 μm to 5 μm, and (area of ​​range A) / (area of ​​range C) is 0.5 to 10. (5) The silica particle material content is 0.2% or more and less than 3% based on the mass of the alumina particle material. (6) The silica particle material and / or the alumina particle material are surface-treated with a silane coupling agent. (7) The silica particle material and / or the alumina particle material contain 0.03% by mass or more and 8.0% by mass or less of carbon derived from the surface treatment agent, based on the mass of the surface-treated particles. (8) The filler material of the present invention that solves the above problems has the above-described mixed particle material. (9) The slurry composition of the present invention that solves the above problems comprises the above-mentioned filler material and a liquid dispersion medium for dispersing the filler material, wherein the filler material is present in an amount of 65% by mass or more and 95% by mass or less, based on the total mass. (10) The resin composition of the present invention that solves the above problems comprises the above-mentioned filler material and a resin material for dispersing the filler material, wherein the filler material is present in an amount of 65% by mass or more and 95% by mass or less, based on the total mass.

[0009] The mixed particle material of the present invention, having the above configuration, can achieve high fluidity and thermal conductivity when used as a resin composition.

[0010] The mixed particle material, filler material, slurry composition and resin composition of the present invention will be described in detail below based on embodiments. The filler material is a material suitable for being dispersed in a resin composition for electronic materials, and the resin composition for electronic materials can be used for sealing materials of semiconductor devices, underfills, substrate materials, and the like.

[0011] It should be noted that the numerical range "x to y" described in the present specification includes the lower limit x and the upper limit y within the range. A new numerical range can be formed by any combination of these upper and lower limits, as well as the numerical values listed in the specification or examples. The new numerical range may also be a range that does not include one or both of the upper limit and the lower limit. Furthermore, any numerical value arbitrarily selected from any of the above numerical ranges can be used as the upper or lower limit of a new numerical range. (Mixed Particle Material) The mixed particle material of the present embodiment is a mixture of an alumina particle material and a silica particle material. The mixed particle material of the present embodiment has a specific surface area of 0.3 m ２ / g or more and 20 m ２ / g or less. As the lower limit of the specific surface area, 0.3 m ２ / g, 0.7 m ２ / g, 1.3 m ２ / g can be exemplified, and as the upper limit, 20 m ２ / g, 10 m ２ / g, 5 m ２ / g can be exemplified. The specific surface area is a value measured by the BET method using nitrogen gas. When the specific surface area is smaller than the upper limit, powder flowability becomes good, which is preferable.

[0012] The alumina particle material contains alumina as a main component, and the silica particle material contains silica as a main component. Here, in the present specification, "containing as a main component" means that the content of the target component is 50% or more based on mass. The lower limit of the content of the target component can be set individually, and examples thereof include 60%, 70%, 80%, 90%, 95%, 99%, and 100% excluding inevitable impurities. Materials that can be contained other than alumina and silica include oxides and nitrides such as Ti and Zr.

[0013] When plotting the particle size distribution of alumina particle material, a peak is observed in range A, between 3 μm and 12 μm. Having a peak in range A results in improved fluidity and thermal conductivity during resin filling. Examples of lower limits for particle size in range A (corresponding to the particle size of the peak present within that range; the same applies hereinafter) include 3 μm, 5 μm, and 7 μm, while examples of upper limits include 12 μm, 11 μm, and 10 μm. In this specification, the area of ​​range A is evaluated in the volume-based particle size distribution. The area of ​​range A is the area enclosed by the volume-based particle size distribution curve, the horizontal axis (frequency 0), and the upper and lower limits of range A (similarly for ranges B and C below, it is the area enclosed by the particle size distribution curve and range B or C). When range A, which has a peak, is larger than this lower limit, thermal conductivity is good, which is preferable, and when range A is smaller than this upper limit, packing performance is good, which is also preferable.

[0014] Furthermore, when plotting the particle size distribution of the alumina particle material, it is preferable that the peak is in range B between 0.1 μm and 1.5 μm. Examples of lower limits for range B include 0.1 μm, 0.15 μm, and 0.2 μm, and examples of upper limits include 1.5 μm, 1.3 μm, and 1.0 μm. It is preferable that range B is larger than this lower limit, as this results in good fluidity of the resin composition, and it is also preferable that the particle size in range B is smaller than this upper limit, as this results in good fluidity of the resin composition.

[0015] The area in range A is preferably 0.5 to 10 times the area in range B. Here, the lower limit of (area in range A) / (area in range B) is preferably 0.5, 1, 1.5, or 2, and the upper limit is preferably 10, 7, 5, or 3. The particle size of the peak in range A is preferably the mode diameter in the alumina particle material. When (area in range A) / (area in range B) is greater than this lower limit, the fluidity of the resin composition is good, which is preferable, and when (area in range A) / (area in range B) is smaller than this upper limit, the fluidity of the resin composition is good, which is also preferable.

[0016] Furthermore, when plotting the particle size distribution of the alumina particle material, it is preferable that the particle size peak is in the range C between 1 μm and 5 μm. Examples of lower limits for range C include 1 μm, 1.5 μm, and 2 μm, while examples of upper limits include 5 μm, 4 μm, and 3 μm. It is preferable that range C is larger than this lower limit because it results in good thermal conductivity, and it is preferable that the particle size in range C is smaller than this upper limit because it results in good fluidity of the resin composition.

[0017] The area in range A is preferably 0.5 to 10 times the area in range C. Here, the lower limit of (area in range A) / (area in range C) is preferably 0.5, 1.0, 1.5, or 2.0, and the upper limit is preferably 10.0, 7.0, 4.0, or 2.5. When (area in range A) / (area in range C) is greater than this lower limit, the fluidity of the resin composition is good, which is preferable, and when (area in range A) / (area in range C) is smaller than this upper limit, the fluidity of the resin composition is good, which is also preferable.

[0018] Examples of alumina particle material D50 include lower limits of 3.0 μm, 4.0 μm, and 5.0 μm, and upper limits of 12.0 μm, 9.0 μm, and 6.0 μm. Examples of alumina particle material D10 include lower limits of 0.2 μm, 0.4 μm, and 0.6 μm, and upper limits of 5.0 μm, 3.0 μm, and 1.0 μm. Examples of alumina particle material D90 include lower limits of 10.0 μm and 15.0 μm, and upper limits of 20.0 μm, 18.0 μm, and 16.0 μm. When the alumina particle material D50 is greater than this lower limit, the fluidity of the resin composition is good, which is preferable, and when D50 is less than this upper limit, the fluidity of the resin composition is also good, which is preferable.

[0019] The alumina particle material preferably has a sphericity of 0.8 or higher, with lower limits of 0.85, 0.9, 0.95, 0.98, and 0.99. In this specification, sphericity is calculated by taking a picture with a SEM and determining the area and perimeter of the observed particle, using the formula: (Sphericity) = {4π × (Area) ÷ (Perimeter)} ２The value is calculated using the formula}. The closer to 1, the closer it is to a perfect sphere. Specifically, the average value measured for 100 particles using image analysis software (Asahi Kasei Engineering Co., Ltd.: A-Image-kun) is adopted. Setting the sphericity above the lower limit is preferable as it results in good packing performance.

[0020] The alumina particle material preferably has an alpha-gelatinization ratio of 5% to 50%. Examples of lower limits for the alpha-gelatinization ratio include 5%, 15%, and 20%, while examples of upper limits include 50%, 40%, and 30%. A alpha-gelatinization ratio higher than this lower limit is preferable because it results in good thermal conductivity, and a alpha-gelatinization ratio lower than this upper limit is preferable because it results in good fluidity during resin mixing.

[0021] The D50 of the silica particle material is between 10 nm and 100 nm, with examples of lower limits of 3 nm, 5 nm, and 10 nm, and upper limits of 100 nm, 50 nm, and 20 nm. It is preferable that the silica particle material be sandwiched between alumina particle materials and exert a roller-like effect. When the D50 of the silica particle material is greater than this lower limit, the powder flowability is good, which is preferable, and when the D50 is less than this upper limit, the powder flowability is also good, which is preferable.

[0022] The silica particle material content is between 0.1% and 4% based on the mass of the alumina particle material. Examples of lower limits for the silica particle material content include 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, and 0.475%, while examples of upper limits include 3.75%, 3.5%, 3.4%, 3.3%, 3.2%, 3.1%, 3%, 2.9%, 2.8%, 2.7%, 2.6%, 2.5%, 2.4%, 2.3%, 2.2%, 2.1%, 2%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, 0.85%, 0.8%, 0.75%, 0.7%, 0.65%, 0.6%, 0.575%, and 0.55%. When the silica particle material content exceeds this lower limit, the powder flowability is good, which is preferable, and when it falls below this upper limit, the thermal conductivity is good, which is also preferable.

[0023] The mixed particle material of this embodiment can be surface-treated with a surface treatment agent. Furthermore, only a portion of the particles contained in the mixed particle material can be surface-treated. Additionally, some or all of the particles in the alumina particle material and the silica particle material can be surface-treated.

[0024] Examples of surface treatment agents include silane compounds such as silane coupling agents, titanate coupling agents, and aluminate coupling agents. Examples of silane compounds include those having alkyl groups, vinyl groups, phenyl groups, styryl groups, amino groups, phenylamino groups, acrylic groups, methacrylic groups, epoxy groups, isocyanurate groups, carboxyl groups, and ureido groups as functional groups. These functional groups may be directly bonded to silicon atoms or bonded via spacers such as alkylene groups. Compounds having two or more of these functional groups are also acceptable.

[0025] The amount of surface treatment agent to react is preferably such that the carbon derived from the surface treatment agent is 0.03% by mass or more and 8.0% by mass or less, based on the mass of the surface-treated particles. Examples of carbon derived from the surface treatment agent include lower limits of 0.05% by mass, 1.0% by mass, and 1.5% by mass, and upper limits of 7.0% by mass, 6.5% by mass, and 6.0% by mass, respectively. It is preferable that the carbon derived from the surface treatment agent is greater than this lower limit, as this results in good fluidity during resin mixing, and it is also preferable that it is less than this upper limit, as this results in good fluidity during resin mixing. (Filler material) The filler material of this embodiment has the mixed particle material of this embodiment described above. In addition to the mixed particle material, the filler material of this embodiment may also contain other inorganic particle materials or organic particle materials. The filler material contains 50% or more of the mixed particle material based on the total mass, with examples of lower limits of content being 60%, 70%, 80%, 90%, 95%, 99%, and 100%. Examples of inorganic particle materials include those composed of metal oxides other than alumina, and examples of organic particle materials include those composed of resin materials such as fluororesins. (Slurry composition and resin composition) The slurry composition of this embodiment comprises the above-mentioned filler material and a liquid dispersion medium for dispersing the filler material. The resin composition of this embodiment comprises the above-mentioned filler material and a resin material for dispersing the filler material. As the above-mentioned filler material can be used, further explanation is omitted. The content ratio of the filler material is 65% by mass or more and 95% by mass or less based on the total mass. It is preferable that the content of the filler material be as high as possible, as long as the filler material can be sufficiently dispersed.

[0026] The dispersion medium is not particularly limited as long as it is in liquid form, but examples include water, organic solvents, and resin material precursors. Examples of organic solvents include alcohols such as methanol, ethanol, and isopropanol; hydrocarbon solvents such as hexane, cyclohexane, octane, toluene, and xylene; and ketones such as acetone and methyl ethyl ketone. The content ratio of the mixed particle material is not particularly limited, but it is preferable to increase it as long as the fluidity of the slurry is maintained.

[0027] The resin material may be a polymer resin material, or a precursor that becomes a polymer through reactions such as polymerization. Furthermore, the resin material may be in solid or liquid form. Here, if the resin material is in liquid form, it can also be called a slurry composition.

[0028] The resin materials that can be used are not particularly limited, and ordinary resin materials such as thermoplastic resins and thermosetting resins, as well as their precursors, can be selected. For example, epoxy resins, polyimides, polycarbonates, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, vinyl chloride, polypropylene, polyethylene, and polyphenylene ether can be used. (Method for manufacturing mixed particle material) An example of a manufacturing method for the mixed particle material of this embodiment described above will be explained. The alumina particle material and silica particle material contained in the mixed particle material can each be manufactured in independent processes. When the alumina particle material and silica particle material are manufactured independently, the mixed particle material can be obtained by simply mixing the two to achieve the mixing ratio in the mixed particle material of this embodiment. ・Method for manufacturing alumina particle material The method for manufacturing the alumina particle material of this embodiment is not particularly limited, but the so-called VMC method, melting method, etc. can be used. By controlling these manufacturing conditions, it is possible to control the particle size distribution of the alumina particle material to have the particle size distribution described above, or to control the particle size distribution to have the required particle size distribution by classifying the manufactured particles.

[0029] The VMC method involves suspending raw material particles made of metallic aluminum in a carrier gas and introducing them into a high-temperature oxidizing atmosphere, where they are explosively combusted to produce gaseous or liquid alumina. Rapid cooling then yields alumina particle material. The resulting alumina particle material can have a high degree of sphericity.

[0030] In the VMC method, the particle size distribution of the resulting alumina particle material can be controlled by controlling the particle size distribution of the raw material particles, the supply rate of the raw material particles, the supply rate of the carrier gas, the temperature of the oxidation atmosphere, and the amount of oxygen. Furthermore, by classifying the obtained alumina particle material, it is possible to obtain alumina particle material with the required particle size distribution. It is preferable to purify the metallic aluminum constituting the raw material particles to the required purity for the manufactured alumina particle material.

[0031] The melting method involves introducing raw material particle materials, such as alumina or aluminum hydroxide, into a high-temperature atmosphere, melting them, and then rapidly cooling them to produce spherical alumina particle material. The particle size distribution of the resulting alumina particle material can be controlled with a similar trend by controlling the particle size distribution of the raw material particle material.

[0032] In the melting method, it is also possible to use granulated material produced by first manufacturing raw material particles with a smaller particle size than the alumina particle material to be manufactured, and then granulating them. This makes it possible to freely select the particle size through granulation. For example, when producing coarse particle material made of alumina by the deflagration method, particles of a specific particle size tend to be produced, but by granulation, coarse particle material of the required size can be obtained. The granulation method is not particularly limited, and granulation can be performed by spray drying or other methods in a slurry dispersed in a dispersion medium. A binder can be included in the dispersion medium. Preferably, the binder is one that decomposes or volatilizes during the spheroidization process.

[0033] When the raw material particle is aluminum hydroxide, a general method for producing aluminum hydroxide can be used, or aluminum hydroxide produced by the so-called underwater spark discharge method can be used. In the underwater spark discharge method, a pair of electrodes made of metal are immersed in water and a voltage is applied to generate a discharge between the electrodes. As a result, the discharge area becomes hot and melts locally, and the molten material peels off from the electrode surface. The peeled molten material reacts with OH groups generated by the discharge to form particles with high sphericity. Both electrodes of the pair are made from metallic aluminum. Since the composition of the metal used for the electrodes is related to the composition of the final particle material produced, it is preferable to use electrodes made from a material in which the content of elements that are undesirable to be included in the final particle material is controlled.

[0034] Alumina particle materials produced by the method described above often have a low alpha-gelatinization rate. Therefore, a subsequent step (alpha-gelatinization step) may be included to increase the alpha-gelatinization rate.

[0035] The gelatinization step involves heating the obtained alumina particle material at 1200°C to 1400°C. While the heating method is not particularly limited, general firing furnaces or microwave heating can be used. Both continuous and batch firing furnaces are acceptable.

[0036] Examples of lower heating temperature limits include 1210°C, 1220°C, and 1230°C, while examples of upper heating temperature limits include 1380°C, 1360°C, and 1340°C. These upper and lower limits can be combined in any way. The heating temperature during the gelatinization process may be constant or variable. If it is variable, it may be gradually increased or gradually decreased. The heating and decreasing processes may be repeated. Preferably, it is a continuous process.

[0037] The heating time should preferably be 5 minutes or more, and preferably 20 minutes or less, during which the food is exposed to the above temperature. The lower limit can be 6, 7, or 8 minutes, and the upper limit can be 19, 18, or 17 minutes. The upper and lower limits can be combined in any way.

[0038] There are no particular limitations on the process until reaching the temperature for the α-forming step (e.g., 1200°C), but it is preferable to raise the temperature from room temperature at a rate in the range of approximately 50°C / min to 500°C / min. Specifically, 70°C / min, 90°C / min, and 110°C / min can be exemplified as the lower limit of the temperature increase rate; and 450°C / min, 400°C / min, and 350°C / min can be exemplified as the upper limit. These upper limit values and lower limit values can be arbitrarily combined.

[0039] There are no particular limitations on cooling after completion of the α-forming step, but it is preferable to lower the temperature at a rate in the range of approximately 50°C / min to 500°C / min. Specifically, 70°C / min, 90°C / min, and 110°C / min can be exemplified as the lower limit of the temperature decrease rate; and 450°C / min, 400°C / min, and 350°C / min can be exemplified as the upper limit. These upper limit values and lower limit values can be arbitrarily combined. Cooling is preferably performed by natural cooling. ・Production of silica particle material Although the method for producing the silica particle material of the present embodiment is not particularly limited, the so-called VMC method and melting method similar to those for the alumina particle material can be employed. Further, as other methods, the following production methods that are easier to produce silica particle materials having smaller particle diameters than the VMC method or the melting method can be employed: a method of forming silica sol by adding an acid after dissolving metallic silicon in an alkali, the Stöber method using alkoxide as a raw material, and the water glass method using an aqueous sodium silicate solution as a raw material.

[0040] By controlling the conditions for producing the silica particle material through these production methods, the silica particle material can be controlled to have the particle size distribution described above, or the produced particles can be classified to obtain the required particle size distribution.

[0041] In the VMC method, raw material particles composed of metallic silicon are suspended in a carrier gas, introduced into a high-temperature oxidizing atmosphere, and burned explosively to generate gaseous or liquid silica. Thereafter, quenching is performed to obtain a silica particle material made of silica. The obtained silica particle material can have high sphericity.

[0042] In the VMC method, controlling the particle size distribution of the obtained silica particle material can be achieved by controlling the particle size distribution of the raw material particle material, the feed rate of the raw material particle material, the feed rate of the carrier gas, the temperature of the oxidizing atmosphere, the amount of oxygen, and the like. Further, by classifying the obtained silica particle material, a silica particle material having a required particle size distribution can be obtained. It is preferable that metallic silica constituting the raw material particle material is purified so as to have a purity required for the silica particle material to be produced.

[0043] The melting method is a method for producing spheroidized silica particle material by feeding a raw material particle material made of silica into a high-temperature atmosphere, melting the material, and then quenching the molten material. The particle size distribution of the obtained silica particle material can be controlled with a similar tendency by controlling the particle size distribution of the raw material particle material. ・Other steps that can be employed in the step of producing alumina particle material and silica particle material As other steps, the method may comprise a surface treatment step of performing surface treatment on the alumina particle material or the silica particle material with a surface treatment agent, and a pulverization step in a case where the alumina particle material or the silica particle material is aggregated. Particularly, when the α-forming step is employed for alumina particle material, aggregation is likely to proceed, and it is preferable to provide a pulverization step when aggregation has proceeded.

[0044] In the surface treatment step, it is preferable to employ the above-mentioned surface treatment agent as the surface treatment agent. The amount described above can be adopted as the amount of the surface treatment agent.

[0045] There is no limitation on the method for performing the surface treatment, and examples include: a method in which the surface treatment agent is directly added into the alumina particle material or silica particle material and mixed by stirring or the like; a method in which the surface treatment agent is dissolved or dispersed in any solvent, then added into the alumina particle material or silica particle material and mixed by stirring or the like; and a method in which the surface treatment agent is heated and vaporized, then supplied to and brought into contact with the alumina particle material or silica particle material. The surface treatment step can be performed independently for each of the alumina particle material and the silica particle material, or can be performed collectively after preparing the mixed particle material.

[0046] After the surface treatment process, the reaction can be required by leaving it at room temperature or by heating it. For example, it can be heated to around 100°C to 150°C.

[0047] The crushing process is a process in which, when agglomeration occurs, the agglomerated alumina or silica particle material is dispersed down to primary particles. Crushing can be carried out using a pulverizer, mixer, etc. A jet mill can be used as the pulverizer. (Method for manufacturing slurry composition and resin composition) The method for manufacturing the slurry composition and resin composition of this embodiment is not particularly limited. For example, the filler material of this embodiment described above can be dispersed in a dispersion medium or resin material to produce them.

[0048] When silica particle materials included in mixed particle materials are manufactured using a wet method, they can be dispersed directly into dispersion media or resin materials without drying. Therefore, even silica particle materials that would normally aggregate upon drying can be added to slurry compositions or resin compositions.

[0049] The mixed particle material, filler material, slurry composition, and resin composition of the present invention will be described in detail below based on the following examples. • Test 1: A large-diameter alumina particle material (manufactured by Admatex) with a volume-average particle size of 10 μm and a small-diameter alumina particle material (manufactured by Admatex) with a volume-average particle size of 0.2 μm were mixed in the ratios described in conditions 1 and 2 of Table 3 to obtain an alumina particle material with a controlled particle size distribution. A mixed particle material was prepared by mixing this alumina particle material with a volume-average particle size of 10 nm (manufactured by Admatex, surface-treated with a silane compound having a phenyl group as a surface treatment agent (carbon content: 6.0%)) in the ratios described in Table 1, and this was used as the test sample for each test example.

[0050] For each test sample, the disk flow area (Table 1), thermal conductivity (Table 2), and FF value (Table 3) were evaluated. The disk flow area and thermal conductivity were measured using a resin composition obtained by dispersing the test sample in epoxy resin (YX4000H) at a filler ratio of 80% based on volume. The disk flow area was evaluated for the resin composition before curing, and the thermal conductivity was evaluated for the resin composition after curing. The resin composition was cured by holding it at 100°C for 3 minutes.

[0051] The disk flow area was measured by placing a 7g pellet of the resin composition on a hot plate heated to 175°C and applying a load with a 20cm diameter disk. The area over which the resin composition spread was measured. Thermal conductivity was measured using the hot disk method. The FF value was evaluated using a powder rheometer.

[0052] As is clear from Table 1, it was found that adding small-diameter alumina particle material increased the disk flow area and improved fluidity. Furthermore, it was found that adding silica particle material also increased the disk flow area. In particular, the disk flow area increased when the silica particle material was added at concentrations of 0.5% and 1%.

[0053] As is clear from Table 2, it was found that the thermal conductivity increased when small-diameter alumina particle material was added. Under these conditions, no significant change in thermal conductivity was observed even when silica particle material was added.

[0054] As is clear from Table 3, it was found that the FF value decreased by adding small-diameter alumina particle material. Furthermore, the FF value could be improved by adding silica particle material, regardless of the presence or absence of small-diameter alumina particle material. The results of measuring D50 and specific surface area for each test sample are shown in Table 4.

[0055] As is clear from Table 4, it was found that the specific surface area increased by adding silica particle material, while D50 remained largely unchanged. • Test 2: By mixing large-diameter alumina particle material (manufactured by Admatex) with a volume-average particle size of 10 μm, medium-diameter alumina particle material (manufactured by Admatex) with a volume-average particle size of 3.0 μm, and small-diameter alumina particle material (manufactured by Admatex) with a volume-average particle size of 0.2 μm, in the ratios listed in Table 5 as conditions 1 to 5 in this test, an alumina particle material with a controlled particle size distribution was obtained.

[0056] As is clear from Table 5, it was found that adding an appropriate amount of medium / small diameter alumina particle material increased the disc flow area and thermal conductivity. Furthermore, the FF value could be improved by adding an appropriate amount of medium / small diameter alumina particle material. Considering both factors together, it was found that condition 4 was preferable. Test 3 The test sample of condition 4 described above was further mixed with silica particle material (the same as that used in Test 1) in the proportions shown in Table 6, and the disc blow area, thermal conductivity, and FF value were measured and shown together.

[0057] As is clear from Table 6, the FF value could be improved by adding silica particle material. However, since the addition of silica particle material tends to decrease thermal conductivity, the test sample under condition 4-4 was found to have a good balance between the decrease in thermal conductivity and the improvement in the FF value. However, the preferred conditions may differ depending on whether thermal conductivity or the FF value is given more importance.

[0058] As is clear from Table 7, it was found that the combinations of small-diameter / medium-diameter alumina particle content are preferably 10% / 30%, 20% / 20%, and 30% / 10%, based on the total mass of the alumina particle material. The silica particle content is preferably 0.5%, 1%, and 3%, based on the mass of the alumina particle material, and is particularly preferably 0.5 to 1.0%.

Claims

1. A mixed particle material comprising an alumina particle material having a peak in the range A of 3 μm or more and 12 μm or less, and a silica particle material having a content of 0.1% or more and 4% or less based on the mass of the alumina particle material, and a particle size of 10 nm or more and 100 nm or less.

2. The specific surface area of ​​the alumina particle material is 0.2 to 20 m². ２ The mixed particle material according to claim 1, wherein the value is / g.

3. The mixed particle material according to claim 1, wherein the alumina particle material has a peak in range B of 0.1 μm to 1.5 μm, and (area of ​​range A) / (area of ​​range B) is 0.5 to 10.

4. The mixed particle material according to claim 1, wherein the alumina particle material has a peak in range C of 1 μm or more and 5 μm or less, and (area of ​​range A) / (area of ​​range C) is 0.5 or more and 10 or less.

5. The mixed particle material according to claim 4, wherein the content of the silica particle material is 0.2% or more and less than 3% based on the mass of the alumina particle material.

6. The mixed particle material according to claim 1, wherein the silica particle material and / or the alumina particle material are surface-treated with a silane coupling agent.

7. The mixed particle material according to claim 6, wherein the silica particle material and / or the alumina particle material contains 0.03% by mass or more and 8.0% by mass or less of carbon derived from the surface treatment agent, based on the mass of the surface-treated particles.

8. A filler material having the mixed particle material according to any one of claims 1 to 7.

9. A slurry composition comprising the filler material described in claim 8 and a liquid dispersion medium for dispersing the filler material, wherein the filler material is present in an amount of 65% by mass or more and 95% by mass or less, based on the total mass.

10. A resin composition comprising a filler material according to claim 8 and a resin material for dispersing the filler material, wherein the filler material is present in an amount of 65% by mass or more and 95% by mass or less, based on the total mass.

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