Composite materials and mixtures

Abstract

The composite material comprises a dispersant having a thermal conductivity of 100 W / K·m or more, and a thermoplastic resin substrate having a volume resistivity of 10 GΩ·cm or more, interposed between the dispersants. The mixture comprises a dispersant having a thermal conductivity of 100 W / K·m or more and having one or more maximum values ​​in its particle size distribution, and a powder having a volume resistivity of 10 GΩ·cm or more, wherein the volume ratio of the volume of the powder to the total volume of the dispersant and the powder is 0.5 volume% or more and 50 volume% or less.

Description

Technical Field

[0001] This disclosure relates to composite materials and mixtures.

Background Art

[0002] Patent Document 1 describes a motor member made of resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In addition to conventional automotive applications, companies are actively developing motors for mobility such as flying cars and unmanned aircraft for mobile phone base stations flying in the stratosphere, etc. Such motors are required to have higher output.

[0005] To achieve higher output, it is necessary to suppress the iron loss of the motor member. In particular, since the eddy current loss increases as the rotational speed of the motor increases, it is required to suppress the eddy current loss of the motor member. To suppress the eddy current loss of the motor member, it is necessary to lower the electrical conductivity of the motor member.

[0006] Also, heat dissipation is important for continuous stable operation and high efficiency of the motor. To promote heat dissipation, it is necessary to increase the thermal conductivity of the motor member. A motor member made of resin has a low thermal conductivity. In one aspect of this disclosure, it is preferable to provide a composite material and a mixture having a low electrical conductivity and a high thermal conductivity.

Means for Solving the Problems

[0007] One aspect of this disclosure is a composite material comprising a dispersant having a thermal conductivity of 100 W / K·m or more, and a thermoplastic resin substrate having a volume resistivity of 10 GΩ·cm or more, interposed between the dispersants. This composite material, one aspect of this disclosure, has low electrical conductivity and high thermal conductivity.

[0008] Another aspect of the present disclosure is a powdered mixture comprising a dispersant having a thermal conductivity of 100 W / K·m or more and having one or more maximum values ​​in its particle size distribution, and a powder having a volume resistivity of 10 GΩ·cm or more, wherein the volume ratio of the volume of the powder to the total volume of the dispersant and the powder is 0.5 vol% or more and 50 vol% or less. Using the mixture in another aspect of the present disclosure, a composite material with low electrical conductivity and high thermal conductivity can be manufactured. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1A is an explanatory diagram showing the form of the mixture. Figure 1B is an explanatory diagram showing the process of manufacturing a composite material from the mixture. Figure 1C is an explanatory diagram showing the form of the composite material. [Figure 2] Figure 2A is an explanatory diagram showing the mixture in the female mold. Figure 2B is an explanatory diagram showing the mixture being loaded by the male mold. Figure 2C is an explanatory diagram showing the manufactured composite material being removed from the female and male molds. [Figure 3] This graph shows the particle size distribution of aluminum particles contained in mixtures and composite materials. [Figure 4] This graph shows the thermal conductivity of composite materials. [Modes for carrying out the invention]

[0010] Exemplary embodiments of this disclosure will be described with reference to the drawings. <First Embodiment> 1. Composition of Composite Material 1 As shown in Figure 1C, the composite material 1 includes a dispersant 3 and a thermoplastic resin substrate 5. The thermoplastic resin substrate 5 is continuously interposed between the dispersants 3.

[0011] The thermal conductivity of the dispersant 3 is 100 W / K·m or higher. The dispersant 3 is, for example, a metal powder. Examples of metals include aluminum, copper, silver, gold, and magnesium, as well as alloys containing these. The dispersant 3 is, for example, a ceramic. Examples of ceramics include aluminum nitride, boron nitride, silicon carbide, beryllium oxide, and diamond-like carbon.

[0012] For example, the mass ratio of aluminum in the dispersant 3 is 50% by mass or more. In this case, the thermal conductivity of the composite material 1 becomes even higher, and the composite material 1 becomes lighter. For example, if the total mass of the dispersant 3 is 100 parts by mass, the dispersant 3 is a mixture of 50 parts by mass or more of aluminum and ceramics.

[0013] For example, of the particles in the dispersant 3, more than 90% have a particle size of 300 μm or less. In this case, the composite material 1 can suppress eddy currents. For example, the particle size distribution of the dispersant 3 has one or more maximum values. It is preferable that the particle size distribution of the dispersant 3 has multiple maximum values. In this case, the thermal conductivity of the composite material 1 is even higher. The method for measuring the particle size distribution of the dispersant 3 is laser diffraction.

[0014] The thermoplastic resin substrate 5 has a volume resistivity of 10 GΩ·cm or more. The thermoplastic resin constituting the thermoplastic resin substrate 5 is, for example, polyphenylene sulfide, polyarylate, polysulfone, polyether ketone, polyethersulfone, polyimide, polyamide imide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene, polymethyl methacrylic, or fluororesin. The glass transition temperature of the thermoplastic resin is, for example, less than the melting point of the dispersant 3.

[0015] When the mass of the dispersant 3 is 100 parts by mass, the mass of the thermoplastic resin base material 5 is preferably 0.5 parts by mass or more and 50 parts by mass or less. When the mass of the thermoplastic resin base material 5 is 50 parts by mass or less, the thermal conductivity of the composite material 1 is even higher.

[0016] The electric conductivity of the composite material 1 is, for example, 0.5×10 6 S / m or less. As a method of reducing the electric conductivity of the composite material 1, there is a method of increasing the amount of the thermoplastic resin base material 5. The thermal conductivity of the composite material 1 is, for example, 20 W / K·m or more. As a method of increasing the thermal conductivity of the composite material 1, there is a method of reducing the amount of the thermoplastic resin base material 5.

[0017] The specific gravity of the composite material 1 is, for example, 2.7 g / cm 3 or less. As a method of reducing the specific gravity of the composite material 1, there is a method of reducing the pressure when manufacturing the composite material 1.

[0018] The composite material 1 can be used, for example, as a material for a structural member of a mobility motor. Examples of the structural member include a cover for the entire motor, a fixing plate for the stator, a fixing plate for the rotor, etc. The composite material 1 is plastically deformable, for example, when heated to a temperature equal to or higher than the softening point of the thermoplastic resin base material 5.

[0019] 2. Mixture 11 The composite material 1 can be manufactured, for example, using the mixture 11 shown in Fig. 1A. The mixture 11 includes a dispersant 3 and a powder 13.

[0020] The dispersant 3 has a thermal conductivity of 100 W / K·m or more. The dispersant 3 is, for example, a metal powder. Examples of the metal include aluminum, copper, silver, gold, magnesium, and alloys containing these. The dispersant 3 is, for example, a ceramic. Examples of the ceramic include aluminum nitride, boron nitride, silicon carbide, beryllium oxide, diamond-like carbon, etc.

[0021] For example, at least a portion of the dispersant 3 contains metallic aluminum or an aluminum alloy. For example, the mass ratio of aluminum in the dispersant 3 is 50% by mass or more. In this case, the thermal conductivity of the composite material 1 manufactured using the mixture 11 becomes even higher, and the composite material 1 manufactured using the mixture 11 becomes lighter. For example, if the total mass of the dispersant 3 is 100 parts by mass, the dispersant 3 is a mixture of 50 parts by mass or more of aluminum and ceramics.

[0022] The dispersant 3 has one or more maximum values ​​in its particle size distribution. Preferably, the particle size distribution of the dispersant 3 has multiple maximum values. In this case, the thermal conductivity of the composite material 1 manufactured using the mixture 11 becomes even higher. For example, more than 90% of the particles in the dispersant 3 have a particle size of 300 μm or less. In this case, the composite material 1 manufactured using the mixture 11 can suppress eddy currents.

[0023] Powder 13 has a volume resistivity of 10 GΩ·cm or more. For example, powder 13 contains a thermoplastic resin. For example, powder 13 consists of a thermoplastic resin. For example, the glass transition point of the thermoplastic resin contained in powder 13 is lower than the melting point of the dispersant 3.

[0024] Examples of thermoplastic resins include polyphenylene sulfide, polyarylate, polysulfone, polyether ketone, polyethersulfone, polyimide, polyamide-imide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene, polymethyl methacrylic, or fluororesin. When the mass of the dispersant 3 is 100 parts by mass, the mass of the powder 13 is preferably 0.5 parts by mass or more and 50 parts by mass or less. When the mass of the powder 13 is 50 parts by mass or less, the thermal conductivity of the composite material 1 produced using the mixture 11 is even higher. The volume ratio of the volume of powder 13 to the total volume of the dispersant 3 and powder 13 is 0.5% by volume or more and 50% by volume or less. This increases the thermal conductivity of the composite material 1 produced using the mixture 11.

[0025] The mixture 11 is in powder form. The mixture 11 can be produced by mixing the dispersant 3 and the powder 13. For mixing, for example, a mortar and pestle can be used. Alternatively, mixing may be done using a ball mill or a rotary-blade mixer. For example, in the mixture 11, the dispersant 3 and the powder 13 are uniformly mixed.

[0026] 3. Method for manufacturing composite material 1 The composite material 1 can be manufactured, for example, by the following method. First, a mixture 11 shown in Figure 1A is prepared. The mixture 11 contains a dispersant 3 and a powder 13. The powder 13 later melts and solidifies to become a thermoplastic resin substrate 5. The powder 13 functions as a binder.

[0027] Next, the mixture 11 is heated and compressed. The temperature during heating and compression is, for example, a temperature at which the thermoplastic resin contained in the powder 13 undergoes a glass transition and the powder 13 softens easily, and is below the melting point of the dispersant 3. During heating and compression, as shown in Figure 1B, the thermoplastic resin softens and becomes a viscous body 15, filling the spaces between the dispersants 3. Also, excess air layers are removed by compression. When the viscous body 15 solidifies, it becomes the thermoplastic resin substrate 5.

[0028] One method for heating and compressing the mixture 11 is to use a compression molding apparatus. The compression molding apparatus comprises a female mold 33 and a male mold 35, as shown in Figures 2A to 2C. The shapes of the female mold 33 and the male mold 35 are arbitrary. As shown in Figure 2A, the mixture 11 is placed inside the female mold 33. Next, as shown in Figure 2B, the mixture 11 can be heated and compressed by pressing down the male mold 35 with a compression molding machine while heating it. When heated and compressed, as shown in Figure 1B, the thermoplastic resin contained in the powder 13 changes into a liquid state and becomes a viscous body 15, filling the spaces between the dispersants 3.

[0029] Next, the female mold 33 and male mold 35 are cooled. At this time, the thermoplastic resin contained in the viscous body 15 hardens, and the composite material 1 is completed. Cooling is, for example, natural cooling. After cooling is complete, the composite material 1 is removed from the female mold 33 and male mold 35 as shown in Figure 2C.

[0030] As a method for heating and compressing the mixture 11, injection molding may be used, in which the heated mixture 11 is pressed into a mold of any shape. Alternatively, as a method for heating and compressing the mixture 11, extrusion molding or back extrusion molding may be used, in which pressure is applied to the heated mixture 11 and it is extruded from an extrusion die of any shape.

[0031] The average particle size, particle size distribution, thermal conductivity, melting point, mass, and chemical composition of the dispersant 3 contained in mixture 11 remain substantially unchanged even after it becomes composite material 1. The volume resistivity, glass transition temperature, mass, and chemical composition of the powder 13 contained in mixture 11 remain substantially unchanged even after it becomes composite material 1.

[0032] 4. Effects of composite material 1 and mixture 11 (1A) Composite material 1 has low electrical conductivity. Due to the low electrical conductivity of composite material 1, even when composite material 1 is installed in a location where the magnetic flux changes rapidly, such as around a rotating motor, it is difficult for induced current to be generated in composite material 1. Because it is difficult for induced current to be generated in composite material 1, energy loss can be suppressed. In addition, composite material 1 has high thermal conductivity. Therefore, composite material 1 can be used as a material for components that require heat dissipation.

[0033] (1B) For example, the specific gravity of composite material 1 can be reduced. When the specific gravity of composite material 1 is low, composite material 1 can be used in a mobile device. Examples of mobile devices include HAPS (Airborne Aerial Stations), eVTOL (Flying Vertical Landing Equipment), electric vehicles, drones, etc.

[0034] (1C) For example, the softening temperature of the thermoplastic resin substrate 5 can be set to a low temperature of about 200 to 300°C. In this case, the composite material 1 has manufacturability equivalent to that of general resin molding methods such as injection molding, extrusion molding, and press molding.

[0035] (1D) For example, after producing a semi-finished product in the shape of a cylinder or cuboid made from composite material 1, warm press molding is possible by heating it again to a temperature above the softening point of the thermoplastic resin base material 5. Examples of warm press molding include forging, extrusion, and back extrusion.

[0036] (1E) Using mixture 11, a composite material 1 that exhibits the effects described in (1A) to (1D) above can be manufactured.

[0037] <Examples> 1. Production of mixtures 11A to 11C Aluminum powder with an average particle size of 190 μm, aluminum powder with an average particle size of 15 μm, and polyphenylene sulfide (PPS) powder with an average particle size of 20 μm were prepared. The average particle size was measured by laser diffraction. The aluminum powder with an average particle size of 190 μm and the aluminum powder with an average particle size of 15 μm correspond to dispersant 3. The PPS powder with an average particle size of 20 μm corresponds to powder 13 having a volume resistivity of 10 GΩ·cm or more.

[0038] The thermal conductivity of aluminum powder with an average particle size of 190 μm and aluminum powder with an average particle size of 15 μm was approximately 230 W / K·m. The melting point of aluminum powder with an average particle size of 190 μm and aluminum powder with an average particle size of 15 μm was approximately 660°C. The glass transition temperature of PPS powder with an average particle size of 20 μm was approximately 93°C. The volume resistivity of PPS powder with an average particle size of 20 μm was 10 9 It was greater than GΩ·cm.

[0039] Of the aluminum powder particles with an average particle size of 190 μm, 97% were particles with a particle size of 300 μm or less. Of the aluminum powder particles with an average particle size of 15 μm, 100% were particles with a particle size of 300 μm or less.

[0040] Mixture 11A was prepared by mixing the following components. Aluminum powder with an average particle size of 190 μm: 10 g PPS powder: 3g

[0041] Mixture 11B was prepared by mixing the following components. Aluminum powder with an average particle size of 190 μm: 5 g Aluminum powder with an average particle size of 15 μm: 5 g PPS powder: 3g

[0042] Mixture 11C was prepared by mixing the following components. Aluminum powder with an average particle size of 15 μm: 10 g PPS powder: 3g When preparing mixtures 11A to 11C, each powder was weighed using an electronic balance and then uniformly mixed in a mortar. After mixing, mixtures 11A to 11C showed no localized color unevenness. This indicated that each powder was thoroughly mixed.

[0043] In mixture 11A, the volume ratio of the volume of PPS powder to the volume of mixture 11A was approximately 37% by volume. The volume of mixture 11A is the sum of the volume of aluminum powder and the volume of PPS powder. In mixture 11B, the volume ratio of the volume of PPS powder to the volume of mixture 11B was approximately 37% by volume. The volume of mixture 11B is the sum of the volume of aluminum powder and the volume of PPS powder. In mixture 11C, the volume ratio of the volume of PPS powder to the volume of mixture 11C was approximately 37% by volume. The volume of mixture 11C is the sum of the volume of aluminum powder and the volume of PPS powder.

[0044] 2. Manufacturing of composite materials 1A to 1C A female mold 33 and a male mold 35 were prepared as shown in Figures 2A and 2C. The female mold 33 was cylindrical with an inner diameter of 20 mm and a height of 50 mm. The male mold 35 was cylindrical with a diameter of 20 mm and a height of 50 mm.

[0045] As shown in Figure 2A, the mixture 11A was placed in the female mold 33. Next, as shown in Figure 2B, the mixture 11A was subjected to a load of 5kN by the male mold 35 and held at 300°C for 30 minutes. After cooling, as shown in Figure 2C, the composite material 1A was removed from the female mold 33 and the male mold 35 to obtain a cylindrically molded composite material 1A.

[0046] Similarly, composite material 1B was obtained using mixture 11B. Also, composite material 1C was obtained using mixture 11C. In composite materials 1A to 1C, the PPS powder became the thermoplastic resin base material 5.

[0047] 2. Evaluation of Composite Materials 1A-1C For each of the composite materials 1A to 1C, the thermal conductivity, electrical conductivity, and specific gravity were measured. The thermal conductivity was measured using the laser flash method. For electrical conductivity, an eddy current conductivity meter was used. The specific gravity was measured by dividing the mass, measured with an electronic balance, by the volume, which was determined by measuring with calipers.

[0048] Figure 3 shows the particle size distribution of aluminum particles contained in mixtures 11A to 11C and composite materials 1A to 1C. In mixture 11A and composite material 1A, the particle size distribution of aluminum particles had one maximum value around 190 μm. In mixture 11C and composite material 1C, the particle size distribution of aluminum particles had one maximum value around 15 μm. In mixture 11B and composite material 1B, the particle size distribution of aluminum particles had two maximum values, one around 190 μm and the other around 15 μm.

[0049] Figure 4 shows the thermal conductivity of composite materials 1A to 1C. The horizontal axis of Figure 4 represents the mass ratio of the mass of aluminum powder with an average particle size of 15 μm to the total mass of aluminum powder. The thermal conductivity of composite material 1A was approximately 5 W / m·K. The thermal conductivity of composite material 1C was 23 W / m·K. The thermal conductivity of composite material 1B was 29 W / m·K.

[0050] Composite material 1B exhibited particularly high thermal conductivity. Composite material 1B contained both aluminum powder with an average particle size of 190 μm and aluminum powder with an average particle size of 15 μm. The reason why composite material 1B had higher thermal conductivity compared to composite material 1A is thought to be that the ratio of aluminum volume to the total volume increased as smaller aluminum particles filled the gaps between larger aluminum particles, thereby increasing the average thermal conductivity.

[0051] The reason why composite material 1B had a higher thermal conductivity compared to composite material 1C is thought to be because the total interface between aluminum particles and resin decreased, resulting in lower thermal resistance. In all composite materials 1A to 1C, the electrical conductivity was below the detection limit. Since the detection limit is 0.5 MS / m, the electrical conductivity of all composite materials 1A to 1C was less than 0.5 MS / m. In all composite materials 1A to 1C, the specific gravity was 2.1 g / cm³. 3 That was the case.

[0052] <Other Embodiments> Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0053] (1) The function of one component in each of the above embodiments may be divided among multiple components, or the function of multiple components may be performed by one component. Also, some of the configurations of each of the above embodiments may be omitted. Also, at least some of the configurations of each of the above embodiments may be added to, replaced with, etc., the configurations of other embodiments.

[0054] (2) In addition to the composite material 1 described above, this disclosure can also be realized in various forms, such as a system that uses the composite material 1 as a component, a method for manufacturing the composite material 1, etc.

[0055] [Technical concepts disclosed in this specification] [Item 1] A dispersant having a thermal conductivity of 100 W / K·m or more, A thermoplastic resin substrate having a volume resistivity of 10 GΩ·cm or more is interposed between the aforementioned dispersants, A composite material containing [the above]. [Item 2] The composite material described in item 1, The glass transition point of the thermoplastic resin substrate is below the melting point of the dispersant. Composite material. [Item 3] A composite material as described in item 1 or 2, Of the particles in the aforementioned dispersant, 90% or more are particles with a particle size of 300 μm or less. The particle size distribution of the aforementioned dispersant has one or more maximum values. Composite material. [Item 4] A composite material described in any one of items 1 to 3, At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. Composite material. [Item 5] A composite material described in any one of items 1 to 4, The mass ratio of aluminum in the aforementioned dispersion is 50% by mass or more. Composite material. [Item 6] A composite material described in any one of items 1 to 5, The thermal conductivity is 20 W / K·m or higher. Composite material. [Item 7] A composite material described in any one of items 1 to 6, Electrical conductivity is 0.5 × 10⁻⁶ 6 It is less than or equal to S / m. Composite material. [Item 8] A composite material described in any one of items 1 to 7, Specific gravity is 2.7 g / cm³ 3 The following is: Composite material. [Item 9] A composite material described in any one of items 1 to 8, The thermoplastic resin substrate is plastically deformable when heated to a temperature above its glass transition point. Composite material. [Item 10] A dispersant having a thermal conductivity of 100 W / K·m or more and having one or more maximum values ​​in its particle size distribution, A powder having a volume resistivity of 10 GΩ·cm or more, Includes, The volume ratio of the volume of the powder to the total volume of the dispersant and the powder is 0.5% by volume or more and 50% by volume or less. A powdered mixture. [Item 11] The mixture described in item 10, The powder contains a thermoplastic resin. mixture. [Item 12] The mixture described in item 11, The glass transition point of the thermoplastic resin is lower than the melting point of the dispersant. mixture. [Item 13] A mixture described in any one of items 10 to 12, Of the particles in the aforementioned dispersant, 90% or more have a particle size of 300 μm or less. mixture. [Item 14] A mixture described in any one of items 10 to 13, At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. mixture. [Item 15] A mixture described in any one of items 10 to 14, The mass ratio of aluminum in the aforementioned dispersion is 50% by mass or more. mixture. [Explanation of Symbols]

[0056] 1, 1A, 1B, 1C… Composite material, 3… Dispersion material, 5… Thermoplastic resin substrate, 11, 11A, 11B, 11C… Mixture, 13… Powder, 15… Viscose, 33… Female type, 35… Male type

Claims

1. A dispersant having a thermal conductivity of 100 W / K·m or more, A thermoplastic resin substrate having a volume resistivity of 10 GΩ·cm or more is interposed between the aforementioned dispersants, Includes, Of the particles in the aforementioned dispersant, 90% or more are particles with a particle size of 300 μm or less. At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. With respect to 100 parts by mass of the dispersant, the mass of the thermoplastic resin substrate is 0.5 parts by mass or more and 50 parts by mass or less. The particle size distribution of the aforementioned dispersant has multiple maximum values, The thermal conductivity is 20 W / K·m or higher. Electrical conductivity is 0.5 × 10 ６ It is less than or equal to S / m. Composite material.

2. A dispersant having a thermal conductivity of 100 W / K·m or more, A thermoplastic resin substrate having a volume resistivity of 10 GΩ·cm or more is interposed between the aforementioned dispersants, Includes, At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. With respect to 100 parts by mass of the dispersant, the mass of the thermoplastic resin substrate is 0.5 parts by mass or more and 50 parts by mass or less. The thermal conductivity is 20 W / K·m or higher. Electrical conductivity is 0.5 × 10 ６ It is less than or equal to S / m. Composite material.

3. A composite material according to claim 1 or 2, The glass transition point of the thermoplastic resin substrate is below the melting point of the dispersant. Composite material.

4. The composite material according to claim 2, Of the particles in the aforementioned dispersant, 90% or more have a particle size of 300 μm or less. The particle size distribution of the dispersant has one or more maximum values. Composite material.

5. A composite material according to claim 1 or 2, The mass ratio of aluminum in the aforementioned dispersant is 50% by mass or more. Composite material.

6. A composite material according to claim 1 or 2, Specific gravity is 2.7 g / cm³ ３ The following is: Composite material.

7. A composite material according to claim 1 or 2, The thermoplastic resin substrate is plastically deformable when heated to a temperature above its glass transition point. Composite material.

8. A dispersant having a thermal conductivity of 100 W / K·m or more and having multiple maximum values ​​in its particle size distribution, A powder having a volume resistivity of 10 GΩ·cm or more, Includes, The volume ratio of the volume of the powder to the total volume of the dispersant and the powder is 0.5% by volume or more and 50% by volume or less. At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. With respect to 100 parts by mass of the dispersion, the mass of the powder is 0.5 parts by mass or more and 50 parts by mass or less. A powdered mixture.

9. A dispersant having a thermal conductivity of 100 W / K·m or more and having one or more maximum values ​​in its particle size distribution, A powder having a volume resistivity of 10 GΩ·cm or more, Includes, The volume ratio of the volume of the powder to the total volume of the dispersant and the powder is 0.5% by volume or more and 50% by volume or less. At least a portion of the aforementioned dispersant includes metallic aluminum or an aluminum alloy. With respect to 100 parts by mass of the dispersion, the mass of the powder is 0.5 parts by mass or more and 50 parts by mass or less. A powdered mixture.

10. A mixture according to claim 8 or 9, The powder contains a thermoplastic resin. mixture.

11. The mixture according to claim 10, The glass transition point of the thermoplastic resin is lower than the melting point of the dispersant. mixture.

12. A mixture according to claim 8 or 9, Of the particles in the aforementioned dispersant, 90% or more have a particle size of 300 μm or less. mixture.

13. A mixture according to claim 8 or 9, The mass ratio of aluminum in the aforementioned dispersant is 50% by mass or more. mixture.

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