Thermally conductive material

Abstract

A thermally conductive material including a material comprising nanofibers and / or a two-dimensional substance, the nanofibers and the two-dimensional substance being represented by the formula MQaOb (wherein M is at least one element selected from the group consisting of elements belonging to Groups 3, 4, 5, 6, and 7, Q is at least one element (excluding O) selected from the group consisting of elements belonging to Groups 12, 13, 14, 15, and 16, a is 0-2, and b is larger than 0 but not larger than 2).

Description

thermal conductive materials

[0001] The present disclosure relates to thermally conductive materials.

[0002] Conventionally, as an oxide containing a metal, for example, TiO ２ For example, AEROXIDE (registered trademark) TiO ２ P-25 is a hydrophilic titanium dioxide with a particle size of 20 to 30 nm and a very high specific surface area. As shown in Non-Patent Document 1, titanium dioxide is suitable for many catalytic applications, particularly photocatalytic applications, due to the ratio of its anatase and rutile crystal structures, and the photocatalytic effect is known to provide, for example, self-cleaning properties in inorganic compositions.

[0003] Teruhisa Ohno, Koji Sarukawa, Kojiro Tokieda, Michio Matsumura, Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases, Journal of Catalysis, Volume 203, Issue 1, 2001, Pages 82-86

[0004] Known TiO ２ However, TiO is difficult to disperse in an aqueous polymer solution and tends to aggregate. ２ Even if a coating film or the like is formed using a polymer aqueous solution containing TiO ２ Therefore, it was difficult to use the coating film as a thermally conductive material with high thermal conductivity. ２ It is conceivable to add a dispersant to improve the dispersibility of the polymer. However, the presence of the dispersant may reduce desired properties, such as thermal conductivity. Furthermore, there is also the problem of the dispersant bleeding out.

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a novel thermally conductive material.

[0006] According to one aspect of the present disclosure, a compound of the formula: ａ O ｂ (wherein M is at least one element selected from the group consisting of Groups 3, 4, 5, 6, and 7; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15, and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less).

[0007] According to the present disclosure, a novel thermally conductive material is provided that includes a predetermined material and exhibits thermal conductivity.

[0008] Conventional TiO as a filler ２ 8 is an explanatory diagram showing the fracture of a polymer composite containing MQO particles of the present embodiment as a filler when pulled. FIG. 9 is an explanatory diagram showing the fracture of a polymer composite containing MQO particles of the present embodiment as a filler. FIG. 10 is a TEM observation photograph of a TiCO film produced in an example. FIG. 11 is a diagram showing the results of Raman spectroscopy of a material (TiCO) produced in an example. FIG. 12 is an SEM observation photograph of a TiCO film produced in an example. FIG. 13 is an XRD pattern of a material (TiCO) produced in an example. FIG. 14 is a schematic diagram showing the anisotropy of thermal conduction in the in-plane direction and thickness direction of a TiCO film produced in an example. FIG. 15 is an XRD pattern of a material (TiCO / polyurethane composite material) produced in an example. FIG. 16 is a diagram in which the XRD patterns of FIG. 6 and FIG. 17 are superimposed. ２ 1 shows the results of evaluating the dispersibility of a water dispersion of titanium dioxide (TiO ２ 1 shows the results of evaluating the dispersibility of an aqueous polyurethane dispersion of the material (TiCO) produced in the examples.

[0009] The present inventors have conducted extensive research to provide a novel thermally conductive material. As a result, they have found that by including a material containing a specific nanofiber and / or two-dimensional substance, a thermally conductive material exhibiting thermal conductivity can be obtained, and further, when the thermally conductive material is in the form of a film, a film exhibiting anisotropy in thermal conductivity in the in-plane direction and thickness direction of the film can be obtained. Furthermore, as shown schematically in Figure 1, TiO, which has conventionally been used as a filler, can be used as a filler. ２ The polymer composite obtained by mixing the resin 1 and the resin 3 without adding a dispersant and then applying the mixture to a PET substrate 5 contains TiO ２ The aggregated regions 1 are likely to form aggregated regions 7, surrounded by dashed lines (Figure 1, left). When the above polymer composite is pulled in the direction of the black arrow, for example, for measuring film strength (tensile testing), fracture failure is likely to occur starting from the aggregated regions 7, as shown in Figure 1, right. In contrast, as shown schematically in Figure 2, a polymer composite obtained by mixing a material 9 containing a predetermined nanofiber and / or two-dimensional material with a resin 3 without adding a dispersant and then applying the mixture to a PET substrate 5 allows the material 9 to be dispersed without agglomeration. While adding a dispersant during mixing with the resin shortens the service life due to degradation of the dispersant, the composite material of this embodiment does not encounter such a problem. As a result, when the film is pulled in the direction of the black arrow, for example, for measuring film strength (tensile testing), fracture is unlikely to occur and the film exhibits high strength.

[0010] Furthermore, when the thermally conductive material is a film, the material containing the specified nanofibers and / or two-dimensional material preferably has a high aspect ratio, and the entanglement of the high-aspect-ratio material allows the formation of a film (also called a "freestanding film") without the need for a binder or the like. Furthermore, by incorporating the specified nanofibers and / or two-dimensional material into a polymer, for example as a filler, a polymer composite coating film that is resistant to breakage can be provided without the use of a dispersant. The thermally conductive material of this embodiment will now be described.

[0011] [Thermal Conduction Material] This embodiment relates to a thermal conduction material including a material containing a predetermined nanofiber and / or two-dimensional material. In this disclosure, the simple term "material" refers to a "material containing nanofibers and / or two-dimensional material" (in other words, a material containing at least one of nanofibers and two-dimensional material). In this embodiment, a material containing nanofibers and / or two-dimensional material typically refers to a material that is solid and does not contain a binder or the like (e.g., a polymer). In a narrow sense, a material containing nanofibers and / or two-dimensional material may refer to a material that is substantially composed of at least one of nanofibers and two-dimensional material (which may contain other objects, impurities, etc. that may be inevitably mixed in). However, materials containing nanofibers and / or two-dimensional material are not limited to these. The thermal conduction material of this embodiment may be a material that is substantially composed of at least one of nanofibers and two-dimensional material (which may contain other objects, impurities, etc. that may be inevitably mixed in).

[0012] (MQO-containing material) The material contained in the thermally conductive material of this embodiment is a nanofiber and / or two-dimensional substance of a predetermined material (substance). The predetermined material that can be used in this embodiment is represented by the following formula (1): MQO ａ O ｂ ... (1) (In the formula, M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7, and may include at least one element selected from the group consisting of so-called early transition metals, for example, Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and Mn, and preferably at least one element selected from the group consisting of Ti, V, Cr, Mo and Mn; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16 (excluding O), and may include at least one element selected from the group consisting of B, C, N, Si, P and S; a is 0 or more and 2 or less; and b is 0 or more and 2 or less.)

[0013] The above-mentioned predetermined material will be hereinafter also referred to simply as "MQO." Examples of MQO include TiO ２ , TiCO, TiCON, VO ２ , VCO, VCON, CrO ２ , CrCO, CrCON, MoO ２ , MoCO, MoCON, MnO ２ , MnCO, MnCON, and the like. For example, in formula (1), M may be Ti and Q may be C. Also, for example, in formula (1), a may not be 0. That is, a may be greater than 0, for example, 1 or greater.

[0014] MQO has a crystal structure different from the hexagonal system. Although the present embodiment is not bound by any theory, the crystal structure of MQO is currently considered to be anatase type, lepidocrocite type, or a mixture of these. For example, the crystal structure of MQO may be lepidocrocite type.

[0015] MQO can be produced, for example, using a first raw material and a second raw material as follows: The first raw material contains at least M, and the second raw material contains at least Q, and the first raw material and the second raw material are capable of reacting in a protic solvent to produce MQO.

[0016] As the first raw material, a material represented by the following formula (2) can be used: M ｃ A １ ｄ ... (2) (wherein M is as defined above, A １ is at least one element selected from the group consisting of Groups 12, 13, 14, 15, and 16, and may include, for example, at least one element selected from the group consisting of B, C, N, O, Si, P, and S; and c and d are each independently 1 to 5. However, the material represented by formula (2) must be different from the product MQO. The material represented by formula (2) may typically have no peak in its X-ray diffraction (XRD) pattern in a diffraction angle 2θ range of 2° to 12°.

[0017] Examples of the first raw material represented by formula (2) include TiB ２ , TiB, TiC, TiN, TiO ２ , Ti ５ Si ３ , Ti ２ SbP, VO ２ , V ２ O ４ , NbC, Nb ２ O ５ , MoO ２ , MoO ３ , MoS ２ , MnO ２ , Mn ３ O ４ , MnCO ３ MnO that can be used as the first raw material ２ In the XRD pattern, the material has a peak near 2θ=13° and no peak in the 2θ range of 2° or more and 12° or less.

[0018] Alternatively, or in addition to the above, a material represented by the following formula (3) (hereinafter also simply referred to as a "MAX phase" or "MAX raw material") may be used as the first raw material. ｍ A ２ X ｎ ...(3) (wherein M is as defined above, X is at least one element selected from the group consisting of C and N, n is 1 or more and 4 or less, m is greater than n and 5 or less, A ２ is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16, and is usually a Group A element, typically Group IIIA and Group IVA, and more particularly may include at least one element selected from the group consisting of Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, S and Cd, preferably Al). The MAX phase is ｍ X ｎ (which may have a crystal lattice where each X is located in an octahedral array of M), ２ The MAX phase has a crystal structure in which layers composed of atoms are located. When m=n+1, typically, one layer of X atoms is located between each of n+1 layers of M atoms (collectively referred to as "M ｍ Xｎ layer), and the layer next to the n+1-th layer of M atoms is A ２ Atomic layer ("A ２ The MAX phase has repeating units arranged in "atomic layers." However, the MAX phase is not limited to this.

[0019] Examples of the first raw material represented by formula (3) include Ti ３ AlC ２ , Ti ３ GaC ２ , Ti ３ SiC ２ These include:

[0020] As the first raw material, the material represented by formula (2) and the material represented by formula (3) may be used together (for example, as a mixture).

[0021] As the second raw material, an ionically bondable substance having a carbon-containing group can be used. The ionically bondable substance having a carbon-containing group contains C. Examples of the ionically bondable substance include ammonium salts, phosphates, sulfates, etc.

[0022] More specifically, a quaternary ammonium salt may be used as the second raw material. Examples of quaternary ammonium salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH or TBAOH), benzyltrimethylammonium hydroxide, tetrabutylammonium fluoride (TBAF), tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI), benzyltriethylammonium chloride (BTEAC), hexadecyltrimethylammonium bromide, cetyltrimethylammonium bromide (CTAB), benzethonium chloride, benzalkonium chloride, and cetylpyridinium chloride (CPC). Among these, TMAH and TBAOH are preferred.

[0023] Alternatively, or in addition to the above, other ion-binding substances containing P and / or S, etc. may be used as the second raw material.

[0024] The protic solvent may be any solvent capable of at least partially dissolving the first and second raw materials, and may be, in particular, an aqueous solvent. Examples of the protic solvent include water, alcohol (e.g., ethanol, 1-propanol, isopropanol), and carboxylic acids (e.g., acetic acid and formic acid). The aqueous solvent may be composed of water and, optionally, a liquid substance compatible with water (e.g., a protic solvent other than water), and is preferably water.

[0025] The first and second raw materials are reacted in a protic solvent. The second raw material can be added to the protic solvent in advance. The ratio of the second raw material to the total of the protic solvent and the second raw material can be, for example, 5% by mass or more, particularly 20% by mass or more, and / or, for example, 80% by mass or less, particularly 50% by mass or less. The first raw material can be further added to the protic solvent to which the second raw material has been added, and mixed. In this mixture, a reaction to produce MQO proceeds. The temperature (reaction temperature) of the mixture (which may contain the reaction product) can be, for example, 15°C or more, particularly 40°C or more, and / or, for example, 100°C or less, particularly 80°C or less. The mixing time (reaction time) can be, for example, one day or more, particularly two days or more, and / or, for example, 10 days or less, particularly 7 days or less. Mixing can be performed, for example, by rotating a magnetic stirrer placed in a container while maintaining the reaction temperature using a hot plate stirrer and a warm water bath. However, the treatment operations and conditions (temperature, time, etc.) that can cause the reaction to proceed are not limited to those described above, and may be selected appropriately depending on the first raw material, second raw material, protic solvent, etc. that are used.

[0026] The above reaction produces MQO, which may eventually grow into MQO nanofibers and further MQO nanoflakes. While not limiting the present disclosure, the resulting MQO nanofibers may be in the form of nanoribbons extending in nanoscale widths. Alternatively, multiple MQO nanofibers (e.g., nanoribbons) may bond and / or integrate with each other to grow into two-dimensionally extending nanoflakes. Alternatively, multiple MQO nanoflakes may overlap each other (e.g., by van der Waals forces) to form stacks. While the present disclosure is not bound by any theory, the production and growth of MQO may be thought of as a bottom-up synthesis reaction.

[0027] In the present disclosure, the cross-sectional outer dimension of an MQO nanofiber refers to the shortest distance passing through the center of a cross section transverse to the longitudinal direction of the MQO nanofiber. The cross-sectional shape of an MQO nanofiber is not particularly limited, but can be approximated, for example, by a rectangle (rectangle, square, etc.) or an ellipse (flattened circle, perfect circle, etc.). When an MQO nanofiber is in the form of a nanoribbon, the cross-sectional shape can be approximated by a rectangle, and the cross-sectional outer dimension can correspond to the length of the short side of the rectangle. When an MQO nanofiber is in the form of a nanofilament, the cross-sectional shape can be approximated by a flattened circle, and the cross-sectional outer dimension can correspond to the length of the short diameter of the flattened circle.

[0028] In the present disclosure, MQO is a solid content. MQO may typically be in the form of particles (or powder).

[0029] The mixture after the reaction (also referred to as a reaction mixture) may be subjected to appropriate post-treatment, such as washing, impact (including shear force), drying (e.g., freeze-drying or heat drying), or pulverization.

[0030] The washing may be carried out using a protic solvent. The same explanation as above may be applied to the protic solvent, and the protic solvent may be washed with, for example, water or alcohol. After washing, a separation operation (centrifugation and / or decantation) may be carried out. The washing and separation operations may be repeated until the pH of the supernatant after centrifugation is, for example, 8 or less.

[0031] Optionally, instead of or in addition to the above washing, washing may be carried out using an aqueous solution of a metal salt. The metal salt may be, for example, a halide (fluoride, chloride, bromide, iodide) of an alkali metal (Li, Na, K, etc.), typically LiCl, NaCl, KCl, etc. Specifically, washing may be carried out using, for example, an aqueous solution of a metal salt having a molar concentration of 1 to 10. After washing, a separation operation (centrifugation and / or decantation) may be carried out. In this case, too, the washing and separation operations may be repeated as necessary until the pH of the supernatant after centrifugation becomes, for example, 8 or less.

[0032] Impact such as vibration and / or ultrasound may be applied during and / or after washing. This can promote the dispersion of MQO particles (e.g., nanofibers / nanoflakes, hereinafter the same). If the MQO particles are aggregated, they can be broken down. This effect is particularly pronounced when impact is applied during washing with an aqueous solution of a metal salt (it is believed that metal cations derived from the metal salt penetrate into the gaps between the aggregates and break them down). Impact can be applied using, for example, one or more of a handshake, an automatic shaker, a mechanical shaker, a vortex mixer, a homogenizer, an ultrasonic bath, etc.

[0033] Since the MQO particles are a solid component, a separation operation can be carried out at any appropriate time to remove unnecessary liquid components, if any. As a final separation operation, for example, a drying operation, typically freeze-drying or thermal drying, may be carried out. Freeze-drying can be carried out, for example, by freezing a mixture containing the MQO particles and a liquid component at any appropriate temperature (e.g., −40° C.) and then drying under reduced pressure. Thermal drying can be carried out, for example, by drying a mixture containing the MQO particles and a liquid component at a temperature of 25° C. or higher (e.g., 200° C. or lower) under atmospheric pressure or under reduced pressure. Pulverization can be carried out using, for example, a mortar and pestle combination, an IKA mill, or the like, without particular limitation. Pulverization may also be carried out after drying.

[0034] In order to obtain a material containing MQO (a predetermined nanofiber and / or two-dimensional substance, typically MQO particles; hereinafter, this may be referred to as an "MQO-containing material") with higher purity, it is preferable to repeat washing and centrifugation multiple times and recover the supernatant after the final centrifugation. This supernatant can be used as is, appropriately diluted with a liquid medium, or dried and then mixed with a liquid medium to form a slurry containing MQO particles. This slurry can be used to produce a film, which can then be used as the thermal conductive material of this embodiment.

[0035] As a result, MQO particles can be obtained as an MQO-containing material. MQO is represented by formula (1), but the MQO-containing material (typically, MQO particles) does not necessarily have to consist solely of the constituent elements of formula (1). While not limiting the present disclosure, the MQO-containing material may optionally have at least one type of modification or terminal T present on its surface selected from the group consisting of hydroxyl groups, chlorine atoms, oxygen atoms, hydrogen atoms, and nitrogen atoms. Furthermore, the MQO-containing material (typically, MQO particles) may have two or more layers, and at least one type selected from the group consisting of ammonium ions (e.g., quaternary ammonium cations) and metal cations (e.g., alkali metal ions, alkaline earth metal ions) may be present between these layers.

[0036] The particle size of the MQO particles may be, for example, 0.01 nm or more, in particular 0.1 nm or more, or even 1 nm or more, and / or may be, for example, less than 1000 nm, in particular 100 nm or less, or even 50 nm or less. Such particles may also be referred to as nanoparticles.

[0037] The particle form of MQO is nanofibers and / or two-dimensional materials. The two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. In this embodiment, the two-dimensional materials are not limited to only nanoflakes and stacks of nanoflakes.

[0038] Nanofibers may also be referred to as nanowires. In the present disclosure, "nanofiber" refers to a solid object extending in the longitudinal direction, the cross-sectional dimensions of which perpendicular to the longitudinal direction (cross-sectional external dimensions) are on the nano-order (i.e., 1 nm or more and less than 1000 nm) or even smaller, sub-nano-order (less than 1 nm, for example, 0.1 nm or more and less than 1 nm). The longitudinal length of a nanofiber is not limited to the nano-order (i.e., 1 nm or more and less than 1000 nm), but may also be on the micron order (1 μm or more and less than 1000 μm). The cross-sectional external dimensions of a nanofiber may be, for example, 0.1 nm or more, particularly 1 nm or more, and may be, for example, 100 nm or less, particularly 50 nm or less, and preferably 30 nm or less.

[0039] In the present disclosure, the term "two-dimensional material" refers to a solid object having a two-dimensionally extending surface (also referred to as a plane or two-dimensional sheet surface) and a thickness that is relatively small compared to the maximum dimension of the surface (which may correspond to the "in-plane dimension" of a particle), with the thickness being on the nano-order (i.e., 1 nm or more but less than 1000 nm) or even smaller, on the sub-nano-order (less than 1 nm, for example, 0.1 nm or more but less than 1 nm). The in-plane dimension is not limited to the nano-order (i.e., 1 nm or more but less than 1000 nm) and may be on the micron-order (1 μm or more but less than 1000 μm). As described above, two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. Nanoflakes may also be referred to as nanosheets or two-dimensional (nano)sheets. The thickness of one layer of nanoflakes may be, for example, 0.01 nm or more, particularly 0.8 nm or more, and may be, for example, 20 nm or less, particularly 3 nm or less. The in-plane dimensions of the nanoflakes may be, for example, 0.1 μm or more, in particular 1 μm or more, and may be, for example, 200 μm or less, in particular 40 μm or less. The nanoflakes may be composed of an aggregate of nanofibers.

[0040] When the particles are nanofibers or nanoflakes, the length of the fiber is defined as the longest side, and the length is 150 nm or more, preferably 300 nm or more, more preferably 500 nm or more, and particularly preferably 1000 nm or more.

[0041] (Aspect Ratio) The large aspect ratio of MQO particles allows for the formation of a freestanding film without the use of a dispersant and / or resin during film formation. Furthermore, when the thermally conductive material is a film, it is easy to obtain a film that exhibits anisotropy in thermal conductivity in the in-plane and thickness directions of the film. Furthermore, by incorporating a material containing a specific nanofiber and / or two-dimensional substance into the polymer, for example as a filler, it is possible to provide a polymer composite coating film that is resistant to destruction even without the use of a dispersant.

[0042] From the above viewpoint, the cross-sectional outer dimension of the nanofiber, which is one of the factors of the aspect ratio, is 100 nm or less, preferably 50 nm or less, more preferably 30 nm or less, and particularly preferably 15 nm or less. From the above viewpoint, it is preferable that the cross-sectional outer dimension of the fiber is small, but from the viewpoint of the strength of the nanofiber, the cross-sectional outer dimension of the nanofiber can be, for example, 0.1 Å or more. The cross-sectional outer dimension of the nanofiber can be determined by the method described in the Examples below.

[0043] The stack of nanoflakes may also be referred to as a multi-layer MQO. The distance (interlayer distance or gap size) between two adjacent nanoflakes (or two adjacent layers of MQO) is not particularly limited.

[0044] Each of the above dimensions can be determined as a number-average dimension (number average of at least 40 dimensions) based on a photograph observed with a scanning electron microscope (SEM), a transmission electron microscope (TEM), or an atomic force microscope (AFM) (after processing by a method such as focused ion beam (FIB) if necessary), or as a distance in real space calculated from the position in reciprocal lattice space of the (002) plane measured by X-ray diffraction (XRD).

[0045] However, it should be noted that the MQO in the present disclosure is not limited to the above-mentioned form and may have any suitable form. Also, it should be noted that the thermal interface material of the present embodiment may have any suitable form as long as it contains an MQO-containing material.

[0046] The MQO-containing material may typically have a peak in an X-ray diffraction (XRD) pattern where the diffraction angle 2θ is in the range of 2° to 12° inclusive. Although the present disclosure is not bound by any theory, it is believed that the MQO-containing material having a peak in an XRD pattern where 2θ is in the range of 2° to 12° inclusive means that the MQO has a crystal structure different from that of well-known metal oxides.

[0047] In the present disclosure, an XRD pattern is a pattern (the vertical axis represents intensity and the horizontal axis represents 2θ) obtained by scanning in the θ-axis direction with an XRD analyzer using CuKα radiation (approximately 1.54 Å) as characteristic X-rays, and may also be referred to as an “XRD profile.” Peaks in an XRD pattern can be identified visually or by using software used with the XRD analyzer.

[0048] Although this embodiment is not limited to this embodiment, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 435-455cm －１ , and 665-745 cm －１ It may have a peak at the position

[0049] Although this embodiment is not limited thereto, the material of this embodiment (more specifically, MQO) has, for example, an anatase type or a lepidocrocite type crystal structure, or a mixture of these. More preferably, it has a lepidocrocite type crystal structure.

[0050] Although this embodiment is not limited to this embodiment, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 435-455cm －１ , and 665-745 cm －１ and when the intensities of the respective peaks are X, Y, and Z, X is the largest.

[0051] Although this embodiment is not limited thereto, more preferably, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 180 to 200 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１and when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

[0052] Although this embodiment is not limited thereto, more preferably, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 180 to 200 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ and a peak at 275 to 295 cm －１ The intensity of the peak is 180 to 200 cm －１ Intensity of the peak at 375-395 cm －１ and the intensity of the peak at 665-745 cm －１ The intensity of the peak may be greater than the intensity of the peak of the peak of the

[0053] In this disclosure, the Raman spectrum is measured with a Raman spectrometer using a 514 nm laser as an excitation light source (the vertical axis represents intensity, and the horizontal axis represents Raman shift). Peaks in the Raman spectrum can be identified visually or by using software used with the Raman spectrometer.

[0054] The MQO-containing material may also contain unreacted first and / or second raw materials as impurities, and may also contain substances derived from the first, second, and / or protic solvents. For example, when a quaternary ammonium salt is used as the second raw material, N may be present (residual) in any form in the MQO-containing material. While not limiting this embodiment, the MQO-containing material may contain ammonium ions or tetramethylammonium ions. Furthermore, when a MAX raw material is used as the first raw material, the MQO-containing material may contain a relatively small amount of residual A atoms, for example, 10% by mass or less relative to the original A atoms, in the present disclosure. The amount of residual A atoms may preferably be 8% by mass or less, more preferably 6% by mass or less. However, even if the amount of residual A atoms exceeds 10% by mass, this may not be a problem depending on the use conditions, etc.

[0055] The thermally conductive material may contain an MQO-containing material. The thermally conductive material may be composed of an MQO-containing material, or may be composed of an MQO-containing material and other materials as long as the thermal conductivity is not impaired. One aspect of the thermally conductive material of this embodiment is composed of a material containing nanofibers and / or two-dimensional materials represented by a specific formula. The term "composed of" is intended to encompass both aspects consisting essentially of a material containing nanofibers and / or two-dimensional materials represented by a specific formula (which may include other objects or impurities that may inevitably be mixed in), and aspects consisting solely of a material containing the nanofibers and / or two-dimensional materials. Another aspect of the thermally conductive material of this embodiment is an aspect in which, in addition to the material containing nanofibers and / or two-dimensional materials represented by a specific formula, other materials are included, such as a liquid medium (described below), a polymer (described below), or an additive suitable for thermally conductive materials. The thermally conductive material may be in the form of a fluid, including a liquid, or a solid.

[0056] When the thermally conductive material is a fluid material, examples of the thermally conductive material include an aqueous dispersion, slurry, paste, or the like, in which an MQO-containing material (e.g., MQO particles) is dispersed in a liquid medium. Regardless of the fluid material, the MQO particles according to this embodiment have high dispersibility and are well dispersed in the liquid medium without agglomeration. Examples of the liquid medium include an aqueous polymer solution containing water and a water-soluble polymer as a resin, for example, in an amount greater than 0% by mass and less than 20% by mass, preferably less than 10% by mass, of the total liquid medium. Examples of the water-soluble polymer include water-soluble polyurethane, water-soluble polyester, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, and poly(N-vinylacetamide).

[0057] As the liquid medium, an organic medium may be used instead of water or as a mixture with water. Examples of the organic medium include acetonitrile, N,N-dimethylacetamide, N,N-dimethylformamide, DMSO, DMF, NMP, acetone, 2-methyl-2-propanol, isopropyl alcohol, ethanol, and methanol.

[0058] The proportion of the MQO-containing material in the fluid thermal conductive material can be set appropriately depending on the application, and may be, for example, 0.1 mass % or more and 99.9 mass % or less.

[0059] When the thermally conductive material is a solid material, the thermally conductive material may be a thermally conductive material (composite) containing an MQO-containing material and a resin (polymer). Examples of the polymer (resin) include alkyl polymers, polymers having an amide bond (-NHCO-), polymers having a urethane bond, polymers having an ester bond, polymers having an ether bond, and acrylic polymers (acrylic resins). Among these, one or more of a resin having an amide bond or a urethane bond and an acrylic resin are preferred. Examples of resins with a negative zeta potential include these resins having an amide bond or a urethane bond and an acrylic resin. Examples of the resins having an amide bond or a urethane bond include polyamideimide (PAI), polyacrylamide (PMA), nylon (a polyamide resin), DNA (deoxyribonucleic acid), acetanilide, and acetaminophen. Examples of acrylic resins include polymers polymerized from monomers having an acrylic group, such as monofunctional acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, and 3-hydroxyethyl (meth)acrylate, and bifunctional acrylates such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, and butylene glycol di(meth)acrylate. Other examples include alkyl polymers having an acrylic group at at least one end, polymers having an ether bond, and polymers having a reactive functional group, such as a hydroxyl group, a carboxyl group, an amino group, an epoxy group, a mercapto group, or an oxazoline group, on the side chain of these polymers.

[0060] The proportion of the polymer in the solid thermally conductive material can be determined in consideration of the desired properties. The proportion of the polymer in the thermally conductive material can be, for example, 0.1% by mass or more, 60% by mass or less, further 50% by mass or less, and even 40% by mass or less. That is, the proportion of the MQO-containing material in the solid thermally conductive material can be appropriately set depending on the application. In one embodiment, the proportion of the MQO-containing material in the solid thermally conductive material can be, for example, 40% by mass or more, further 50% by mass or more, and even 60% by mass or more, and can be 99.9% by mass or less.

[0061] The MQO-containing material according to this embodiment has high dispersibility, and is therefore well mixed with the polymer, resulting in a polymer composite in which the MQO-containing material is well dispersed without aggregation. The MQO-containing material and polymer can be stirred using a dispersing device such as a homogenizer, a propeller stirrer, a thin film rotary stirrer, a planetary mixer, a mechanical shaker, a vortex mixer, or a high-pressure disperser.

[0062] When the thermally conductive material of this embodiment is solid, it may be, for example, in the form of a film. A film-like thermally conductive material can be formed using, for example, a slurry, which is a mixture of MQO particles and a polymer, which is the fluid-like thermally conductive material. For example, the slurry, which is a mixture of MQO particles and a polymer, can be applied to a substrate (e.g., a substrate) to form a film-like thermally conductive material. However, the application method is not limited. Examples include spray application using a nozzle such as a one-fluid nozzle, a two-fluid nozzle, or an airbrush; slit coating using a table coater, comma coater, or bar coater; screen printing; metal mask printing; and application methods such as spin coating, immersion, and dripping. The application and drying may be repeated multiple times as necessary until a film of the desired thickness is obtained. Drying and curing may be performed, for example, at a temperature of 400°C or less using an atmospheric pressure oven or a vacuum oven.

[0063] Although the present disclosure is not bound by any theory, one of the reasons for the high dispersibility of the MQO particles according to this embodiment is thought to be the large absolute value of the zeta (ζ) potential. It is also thought that the absolute value of the zeta potential of the MQO particles themselves is large, and that dispersion is maintained by electrostatic repulsion. When the zeta potential is measured by the following method, the absolute value of the zeta potential can be, for example, 1 or more, and preferably 10 or more. A large absolute value of the zeta potential allows for good dispersibility when mixed with a polymer, for example. As a result, the MQO particles according to this embodiment are dispersed, and destruction originating from particle aggregates is suppressed, resulting in a polymer composite coating film that is less susceptible to destruction.

[0064] The zeta potential was measured using ion-exchanged water as a dispersion medium, and the particles of MQO or TiO ２ The particle concentration is adjusted to 0.01 to 0.1% by mass, and the dispersion is permeated with a vortex mixer for 5 minutes. Using the dispersion, measurements are performed under atmospheric conditions using a zeta potential measuring device (Zetasizer Nano-ZS, Malvern Panalytical, Malvern, U.K.).

[0065] Although the thermally conductive material in one embodiment has been described above in detail, various modifications of the present disclosure are possible. Note that the material of the present disclosure may be manufactured by a method different from the manufacturing method in the above-described embodiment.

[0066] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the above-mentioned and below-mentioned aims, and all such modifications are included in the technical scope of the present invention.

[0067] [Example 1: TiCO film] [Preparation of slurry containing TiCO] First, titanium diboride (TiB ２1 g of tetramethylammonium hydroxide (TMAH) (manufactured by Alfa Aesar) and 10 mL of a 25% by weight aqueous solution (manufactured by Alfa Aesar) of tetramethylammonium hydroxide (TMAH) were added. A stirrer tip with a length (35 mm) approximately the same size as the inner diameter of the circular bottom of the container was placed therein. The container was maintained at 80°C in an oil bath, and the mixture in the container was stirred with the stirrer tip for 120 hours, allowing the reaction to proceed. The reaction mixture in the container was then transferred to a centrifuge tube. The solids were allowed to settle by centrifugation at 3500 G for 5 minutes using a centrifuge. (i) After centrifugation, the supernatant was discarded, (ii) 40 mL of ethanol (manufactured by Fisher Chemical) was added to the remaining sediment in the centrifuge tube, and the resulting mixture was dispersed using a vortex mixer for 5 minutes (reslurry), and (iii) centrifuged under the same conditions as above. These steps (i) to (iii) were repeated until the pH of the supernatant became 8 or less. After repeating the steps three times, the pH of the supernatant became 8 or less, so the supernatant was discarded and the repeating procedure was terminated. 40 mL of pure water was added to the remaining sediment in the centrifuge tube, and the mixture was shaken and stirred for 5 minutes using a vortex mixer. Then, the mixture was centrifuged at 3500 G for 30 minutes using a centrifuge, and the supernatant was recovered as a slurry containing TiCO as MQO.

[0068] (TEM Observation and Measurement of Cross-Sectional Dimensions of Nanofibers) The shape of the TiCO film was observed using a TEM. Specifically, the TiCO-containing slurry prepared above was diluted 1000 times and dropped onto a TEM substrate. A Pt / Pd vapor deposition process (40 mA, 30 s) was performed, and the cross section of the TiCO film in the thickness direction was observed using a TEM. An example of the observation results is shown in a microscopic photograph in Figure 3. The dark, approximately 300 nm-wide portion at the bottom of Figure 3 is the carbon reinforcement portion of the TEM substrate. The other fibrous portion in Figure 3 is the material of this embodiment, and it was confirmed that numerous entangled nanofibers were obtained. The dotted circle in Figure 3 represents an isolated portion of the nanofibers that were not entangled. The width was measured at five points above and below the center of the nanofiber in the dotted line (10 points in total) at 10 nm intervals. This was performed at four points within the dotted line, and the average value of a total of 40 points was calculated. This confirmed that nanofibers with a cross-sectional dimension of 14 nm were obtained.

[0069] (Measurement of Zeta Potential) The zeta potential of the TiCO slurry was measured and found to be −80 mV, which was a larger absolute value than the −0.5 mV of the conventional titanium dioxide (P-25) slurry (aqueous dispersion).

[0070] (Raman Spectroscopic Analysis) Using the TiCO slurry, a Raman spectrum was obtained by measuring with a Raman spectrometer (manufactured by Renishaw, product number: InVia) using a laser beam with a wavelength of 514 nm as an excitation light source. An example of the measurement results is shown in FIG. 4. From FIG. 4, it can be seen that the Raman shift is 275 to 295 cm －１ , 435-455cm －１ , and 665-745 cm －１ It is clear that the compound has a lepidocrocite-type crystal structure. The Raman shift is at least 180 to 200 cm －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ It can be seen that when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

[0071] [Preparation of TiCO Film] To analyze the component composition, structure, etc. of the obtained TiCO, a TiCO film (also referred to as a TiCO film, "TiCO single film") was prepared using the TiCO-containing slurry as follows. 1 mL of the TiCO-containing slurry was dispensed and mixed with 20 mL of pure water, and then the mixture was vibrated in a vortex mixer for 5 minutes. The mixture thus obtained was subjected to suction filtration overnight using a Nutsche filter. A membrane filter (Durapore, pore size 0.22 μm, manufactured by Merck Ltd.) was used as the filter for suction filtration. After suction filtration, the precursor film on the filter was dried overnight at 80°C in a vacuum oven, and the filter was removed to obtain a film (freestanding film).

[0072] (SEM Observation) The shape of the TiCO film was observed by SEM. Specifically, the film prepared above was manually split to expose a cross section, and the cross section was observed by SEM. The SEM observation photograph is shown in Figure 5. From Figure 5, it can be seen that the TiCO film is a laminate of nanofibers and / or nanoflakes made of nanofibers.

[0073] (X-ray Photoelectron Spectroscopy (XPS) Analysis) The obtained TiCO film (freestanding film) was analyzed by X-ray photoelectron spectroscopy (XPS). In the obtained XPS spectrum, peaks corresponding to Ti2p, C1s, O1s, and N1s were observed, and therefore Ti, C, O, and N were detected. Since N is considered to be a residue of the raw material TMAH, the material of the freestanding film is considered to be composed of Ti, C, and O.

[0074] (Measurement of XRD Pattern) The XRD pattern of the obtained film (freestanding film) was measured using an XRD device (MiniFlex, manufactured by Rigaku Corporation) (characteristic X-rays: CuKα=1.54 Å). The obtained XRD pattern is shown in FIG. 6. As can be seen from FIG. 6, this material had a peak of the (001) plane at 2θ=7.7° and a peak of the (002) plane at 2θ=15.4°. This indicates that this material has a periodic structure in the thickness direction.

[0075] [Evaluation] The thermally conductive materials (films) of the above-mentioned Examples and Comparative Examples were evaluated as follows.

[0076] [Evaluation of thermal conductivity of TiCO film] Using a tabletop xenon flash analyzer (instrument name: LFA 467 HyperFlash, manufactured by NETZSCH), the specific heat capacity and thermal diffusivity of the TiCO film (TiCO film) were measured according to the laser flash method (ASTM E1461), and the thermal conductivity of the TiCO film was calculated. The thermal diffusivity in the in-plane direction of the flat sample was determined by pulse-heating the surface of the sample with a xenon lamp and observing the heat diffusion from the heated portion to the portion moving in the in-plane direction as the time change in the temperature of the back surface of the sample. The thermal diffusivity in the thickness direction of the flat sample was determined by pulse-heating the surface of the sample with a xenon lamp and observing the heat diffusion from the heated portion to the portion moving in the thickness direction as the time change in the temperature of the back surface of the sample.

[0077] As a result, the specific heat capacity (c ρ ) is 1.93 J / (g·K), and the thermal diffusivity (a) in the in-plane direction is 2.97 mm ２ The thermal conductivity (l) in the in-plane direction was 8.67 W / (m·K). The thermal diffusivity (a) in the thickness direction was 0.17 mm. ２ / s, and the thermal conductivity (l) in the thickness direction was 0.51 W / (m K). Figure 7 is a diagram that schematically explains the anisotropy of thermal conduction in the in-plane and thickness directions of the TiCO film. As shown in Figure 7, the thermal conductivity in the in-plane direction indicated by the black arrow is sufficiently larger than the thermal conductivity in the thickness direction indicated by the white arrow, and it was confirmed that the TiCO film exhibits anisotropy of thermal conduction.

[0078] On the other hand, titanium dioxide (TiO ２ A water dispersion of titanium dioxide (TiO) was used and subjected to suction filtration using a membrane filter, but a film (free-standing film) could not be obtained. ２ ) in an aqueous dispersion of titanium dioxide (TiO ２This is thought to be due to the poor dispersibility of titanium dioxide (TiO) and its nanoparticle shape. TiCO is a one-dimensional material (nanofiber) and / or two-dimensional material, and is easy to form a film, whereas titanium dioxide is in a particle form, making it difficult to form a coating. ２ Since it was not possible to form a film containing ZnO), it was also not possible to evaluate the thermal conductivity of the film.

[0079] Example 2 TiCO / Polyurethane Composite Film Preparation of TiCO-Containing Slurry A slurry containing TiCO as MQO was obtained in the same manner as in Example 1 (Preparation of TiCO-Containing Slurry).

[0080] [Preparation of Resin Slurry and Mixing of Resin Slurry with Slurry Containing TiCO] Polyurethane (Rezamin D-4080 (polyether / carbonate type) manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) and pure water were mixed in a ratio of 1:9 and stirred for 5 minutes with a vortex mixer to obtain a resin slurry.

[0081] The resin slurry, pure water, and a slurry containing TiCO were mixed so as to obtain a TiCO / polyurethane composite material in which the ratio of polyurethane to TiCO (after film formation and drying) was 30 mass %. The mixture was stirred for 5 minutes with a vortex mixer to obtain a mixed slurry of TiCO and resin.

[0082] [Preparation of TiCO / Polyurethane Composite Film (1) Suction Filtration] The TiCO / resin mixed slurry prepared above was subjected to suction filtration overnight using a Nutsche filter. A membrane filter (Durapore, pore size 0.22 μm, manufactured by Merck Ltd.) was used as the suction filtration filter. After suction filtration, the precursor film on the filter was dried overnight at 80°C in a vacuum oven, and the filter was removed to obtain a TiCO / polyurethane composite film (a free-standing film, also referred to as a "TiCO / polyurethane composite film").

[0083] [Preparation of TiCO / Polyurethane Composite Film (2) Spray Coating] The TiCO / resin mixed slurry prepared above was spray coated onto a PET substrate using an airbrush with a spray nozzle. The spray irradiation and drying with a dryer were repeated until the film thickness of the TiCO / polyurethane composite material reached 5 μm. After coating, the film was dried in a normal pressure oven at 80°C for about 30 minutes to obtain a TiCO / polyurethane composite film (TiCO / polyurethane composite material film).

[0084] [Measurement of XRD Pattern of TiCO / Polyurethane Composite Film] The TiCO / polyurethane composite film (freestanding film) obtained by the above [Preparation of TiCO / Polyurethane Composite Film (1) Suction Filtration] was used to measure the XRD pattern (characteristic X-ray: CuKα = 1.54 Å) using an XRD device (MiniFlex, manufactured by Rigaku Corporation). The obtained XRD pattern is shown in Figure 8. Figure 9 shows a diagram in which this Figure 8 and the XRD profile in Figure 6 are superimposed. As can be seen from Figure 8, the TiCO / polyurethane composite film had a (001) plane peak at 2θ = 7.7° and a (002) plane peak at 2θ = 15.5°. As shown in Figure 9, the peak positions were not significantly different from those of the TiCO film alone, indicating that this TiCO mixed with the resin still maintained a periodic structure in the thickness direction.

[0085] [Evaluation of Film Strength] The TiCO / polyurethane composite film obtained by the above [Preparation of TiCO / polyurethane Composite Film (2) Spray Coating] and the TiO2 / polyurethane composite film obtained in the same manner as the TiCO / polyurethane composite film were ２ Polyurethane composite films were prepared. Using these composite films, a tape peel test was performed as follows to measure the strength of each composite film. Details of the strength measurement of the composite films are as follows: Adhesive tape (3M, 6122MP Scotch® Magic™ TAPE, ¾ inch wide) was attached to a portion of the upper surface of a composite film formed on a PET substrate, and then peeled off. Cohesive failure of the composite film, i.e., the presence or absence of internal separation due to transfer of a portion of the composite film to the adhesive surface of the tape, was visually confirmed.

[0086] As a result, no cohesive failure was observed for the TiCO / polyurethane composite film. On the other hand, cohesive failure was observed for the titanium dioxide / polyurethane composite film. This is because the titanium dioxide (TiO ２ ) in aqueous dispersions, resulting in a poor dispersibility of titanium dioxide (TiO ２ This is thought to be due to poor dispersibility of the

[0087] [Evaluation of Thermal Conductivity of TiCO / Polyurethane Composite Film] In the same manner as in the evaluation of the thermal conductivity of the TiCO film, the thermal diffusivity in the in-plane direction of the flat plate sample and the thermal diffusivity in the thickness direction of the flat plate sample were determined.

[0088] As a result, the specific heat capacity (c ρ ) is 1.86 J / (g·K), and the thermal diffusivity (a) in the in-plane direction is 2.85 mm ２ The thermal conductivity (l) in the in-plane direction was 7.36 W / (m·K). The thermal diffusivity (a) in the thickness direction was 0.14 mm. ２ / s, and the in-plane thermal conductivity (l) in the thickness direction was 0.37 W / (m K), confirming the anisotropy of thermal conduction. Furthermore, the thermal conductivity was almost unchanged from that of the TiCO film (TiCO film) of Example 1. This is thought to be due to the high aspect ratio of TiCO, the thermal conduction path being maintained even after mixing with the resin, and the good compatibility between TiCO and the resin, resulting in good dispersion of TiCO in the resin.

[0089] The TiCO film and TiCO / polyurethane composite film of the present embodiment having the above-described properties can be provided, for example, between electronic components. This is because a thin device cannot be equipped with a conventional bulky heat sink. Therefore, it is believed that the TiCO film and TiCO / polyurethane composite film can suppress the transfer of heat between electronic components such as CPUs and SSDs and dissipate heat in the in-plane direction of the film, thereby contributing to the suppression of heat-induced deterioration in the performance of devices including the electronic components.

[0090] [Evaluation of Dispersibility] The present inventors separately conducted a test using titanium dioxide (TiO ２ ) aqueous dispersion (titanium dioxide concentration: 2% by mass), titanium dioxide (TiO ２ An aqueous polyurethane dispersion of TiCO(MQO) particles (concentration of titanium dioxide: 1% by mass, concentration of polyurethane: 1% by mass) according to the present embodiment, and an aqueous polyurethane dispersion of TiCO particles (concentration of TiCO particles: 1% by mass, concentration of polyurethane: 1% by mass) according to the present embodiment were placed in a glass container and left to stand. After leaving the containers for 4 days, the bottoms of the glass containers were visually inspected. Photographs of the containers are shown in Figures 10 to 12. A circular white precipitate was observed in the center of the photograph in Figure 10, and a circular white precipitate was observed in the center of the photograph in Figure 11. As is clear from the photographs in Figures 10 and 11, titanium dioxide had precipitated at the bottom of the glass container. In contrast, as shown in the photograph in Figure 12, no precipitation of TiCO particles was observed in the aqueous polyurethane dispersion of TiCO(MQO) particles according to the present embodiment, even after 4 days (note that the white area at the top of the photograph in Figure 12 is due to the background being mixed in and not a precipitate). It is believed that the high dispersibility of the TiCO particles according to the present embodiment contributes to the excellent thermal conductivity and other properties of films containing the TiCO particles.

[0091] This application claims priority to U.S. Application No. 63 / 609,377, filed December 13, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. The formula: MQ ａ O ｂ (wherein M is at least one element selected from the group consisting of groups 3, 4, 5, 6, and 7; Q is at least one element selected from the group consisting of groups 12, 13, 14, 15, and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less.

2. The thermally conductive material of claim 1, wherein the nanofibers have a cross-sectional dimension of 100 nm or less.

3. The thermal conductive material according to claim 1 or 2, which has a peak in an X-ray diffraction pattern at a diffraction angle 2θ in the range of 2° or more and 12° or less.

4. In the Raman spectrum using a 514 nm laser, the Raman shift is 275 to 295 cm －１ , 435-455cm －１ , and 665-745 cm －１ The thermal conductive material according to any one of claims 1 to 3, having a peak at a position 5. The thermal conductive material according to any one of claims 1 to 4, which has a crystal structure of anatase type or lepidocrocite type, or a mixture of these.

6. The thermal conductive material according to any one of claims 1 to 5, having a lepidocrocite type crystal structure.

7. In the Raman spectrum using a laser with a wavelength of 514 nm, the Raman shift is at least 180 to 200 cm －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ and a peak at 275 to 295 cm －１ The intensity of the peak is 180 to 200 cm －１ Intensity of the peak at 375-395 cm －１ and the intensity of the peak at 665-745 cm －１ The thermal conductive material according to any one of claims 1 to 6, wherein the intensity of the peak is greater than or equal to the intensity of the peak of 8. The thermal conductive material according to any one of claims 1 to 7, which is a composite material containing a resin.

9. The thermal conductive material according to claim 8, wherein the resin comprises a resin having a negative zeta potential.

10. The thermal conductive material according to claim 8 or 9, wherein the resin is at least one of a resin having an amide bond or a urethane bond, and an acrylic resin.

11. The thermal conductive material according to any one of claims 8 to 10, wherein the resin accounts for 5 mass % or more of the thermal conductive material.

12. The thermal conductive material according to any one of claims 1 to 11, which is in the form of a film.

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