Boron nitride material and product including same

Abstract

The boron nitride material according to the present disclosure comprises two or more hexagonal boron nitrides, and a carbazole-ring-containing compound that adheres to at least a portion of the surfaces of the two or more hexagonal boron nitrides. The boron nitride material is in the form of flakes. Each of the two or more hexagonal boron nitrides is in the form of flakes.

Description

Boron nitride materials and their application products

[0001] The present disclosure relates to boron nitride materials and applied products thereof.

[0002] In recent years, in the electronics field, the level of performance required of electronic devices has been increasing in preparation for the expansion of fifth-generation mobile communication systems (5G). For example, 5G uses higher frequency bands to achieve faster communication speeds than previous generations. This means that electronic devices require wiring boards that can handle high frequencies.

[0003] Furthermore, high-capacity communications such as 5G use high-frequency bands, resulting in short radio wave transmission distances. This necessitates increased output power from electronic devices. Furthermore, with the realization of high integration and miniaturization, circuit packaging density also increases. Meeting these needs increases the amount of heat generated per unit area of ​​the wiring board. Therefore, wiring boards are required to have high heat dissipation properties. To improve the heat dissipation properties of wiring boards, it is conceivable to increase the thermal conductivity of the wiring board by incorporating a filler, which is a filling agent with excellent thermal conductivity, into the substrate material that constitutes the insulating layer of the wiring board.

[0004] Boron nitride is a material with high thermal conductivity, excellent heat dissipation properties, and excellent electrical insulation properties, and for this reason, boron nitride particles have attracted attention as a filler for the insulating layer of wiring boards (see, for example, Patent Document 1).

[0005] JP 2018-043899 A Japanese Patent No. 6847219

[0006] Yi-Tao Liu, Xu-Ming Xie and Xiong-Ying Ye, Chem. Commun., 2013, 49, 388-390Rice NA, Bodnaryk WJ, Tamblyn I, et al., J Polym Sci., 2020,58, 1889-1902

[0007] The present disclosure provides boron nitride materials with excellent thermal conductivity.

[0008] The boron nitride material of the present disclosure includes two or more hexagonal boron nitrides and a compound containing a carbazole ring attached to at least a portion of the surface of the two or more hexagonal boron nitrides. The boron nitride material has a flaky shape. Each of the two or more hexagonal boron nitrides has a flaky shape.

[0009] According to the present disclosure, a boron nitride material having excellent thermal conductivity can be provided.

[0010] Fig. 1 is a diagram showing a schematic configuration of one embodiment of a boron nitride material of the present disclosure. Fig. 2 is a schematic explanatory diagram showing one embodiment of a state in which the particle size of the boron nitride material of the present disclosure is reduced by deagglomeration. Fig. 3 is a diagram showing a schematic configuration of one embodiment of a resin composition of the present disclosure. Fig. 4 is a schematic cross-sectional view of one embodiment of a film with a resin layer of the present disclosure. Fig. 5 is a schematic cross-sectional view of one embodiment of a metal foil with a resin layer of the present disclosure. Fig. 6 is a schematic cross-sectional view of one embodiment of a metal-clad laminate of the present disclosure. Fig. 7 is a schematic cross-sectional view of one embodiment of a wiring board of the present disclosure.

[0011] Representative embodiments of the present disclosure will be described below. The embodiments described below are representative examples of the present disclosure, and the present disclosure is not limited to the embodiments described below.

[0012] <<Knowledge Forming the Basis of the Present Disclosure>> Boron nitride is a material with high thermal conductivity, excellent heat dissipation, and excellent electrical insulation. Therefore, boron nitride can be used as a filler in resin compositions used in thermally conductive sheets, heat dissipation sheets, sealants filled in small gaps, and the like. In particular, hexagonal boron nitride, which has a hexagonal crystal structure, has a layered structure similar to graphite, can be synthesized relatively easily, and can have particularly excellent properties such as thermal conductivity, heat dissipation, and electrical insulation.

[0013] Here, primary particles of hexagonal boron nitride are generally flat, scaly boron nitride primary particles, and exhibit thermal conductivity anisotropy, i.e., high thermal conductivity in the (0001) in-plane direction (i.e., width direction) and low thermal conductivity in the thickness direction. Therefore, they exhibit thermal conductivity anisotropy, exhibiting high thermal conductivity in the width direction of the particles but low thermal conductivity in the thickness direction of the particles. This property is also shared by scaly boron nitride secondary particles, which are aggregates of scaly boron nitride primary particles. When a resin composition containing at least one type of scaly boron nitride particles selected from the group consisting of scaly boron nitride primary particles and scaly boron nitride secondary particles is molded into a resin sheet by pressing or the like, the pressure applied during molding tends to cause the scaly boron nitride particles to orient parallel to the surface of the resin sheet. In such a resin sheet, the thermal conductivity in the thickness direction is lower than that in the plane direction.

[0014] Therefore, the inventors used the material development simulation software GeoDict to perform a heat transfer simulation of the thermal conductivity in the thickness direction of a resin sheet when all of the scaly boron nitride particles were oriented parallel to the surface of the resin sheet. The thermal conductivity of the scaly boron nitride particles in the width direction was set to 160 W / mK, the thermal conductivity of the scaly boron nitride particles in the thickness direction was set to 2 W / mK, the thermal conductivity of the resin was set to 0.17 W / mK, and the shape of the scaly boron nitride particles was set to approximate a flat particle with a thickness of 1 μm. The diameter of the planar portion of the scaly boron nitride particles was set to three levels: 8 μm, 12 μm, and 17 μm. The scaly boron nitride particles were randomly arranged so that the volume fraction of the scaly boron nitride particles in the resin sheet was 25%. The heat transfer simulation of the effective thermal conductivity in the thickness direction of the resin sheet resulted in the results shown in Table 1.

[0015]

[0016] As shown in Table 1, it was found that the smaller the diameter of the flat portion of the scaly boron nitride particles, the higher the thermal conductivity. From these results, it can be seen that when the scaly boron nitride particles are oriented parallel to the surface of the resin sheet, the smaller the particle size of the scaly boron nitride particles, the higher the effective thermal conductivity in the thickness direction of the resin sheet. Therefore, the inventors worked on designing scaly boron nitride particles with a small particle size.

[0017] Furthermore, when blending scaly boron nitride particles with resin to prepare a resin composition, the resin dissolved in a solution may be mixed with the scaly boron nitride particles to form a varnish, or the liquid resin may be mixed with the scaly boron nitride particles to form a heat-dissipating paste. However, due to the high specific gravity of boron nitride, the scaly boron nitride particles easily settle in the resin solution or liquid resin, resulting in problems such as a short pot life and difficulty in maintaining a uniform varnish or paste. One way to solve these problems is to reduce the particle size of the scaly boron nitride particles to delay settling. In this respect, too, designing scaly boron nitride particles with a small particle size is extremely beneficial.

[0018] Non-Patent Document 1 discloses a method for producing boron nitride nanosheets from hexagonal boron nitride particles by ultrasonic treatment and then modifying their surfaces with a polymer. The boron nitride nanosheets are presumed to have smaller particle sizes than the original hexagonal boron nitride, but producing the boron nitride nanosheets requires long ultrasonic treatment times and has a very low yield, posing problems in terms of production efficiency and cost.

[0019] Patent Document 2 discloses a method for modifying the surfaces of boron nitride particles with a specific compound, but does not mention that this changes the particle size of the hexagonal boron nitride particles.

[0020] Non-Patent Document 2 discloses a method for modifying the surface of boron nitride nanotubes with a specific organic compound. However, Non-Patent Document 2 does not mention hexagonal boron nitride or thermal conductivity. Furthermore, boron nitride nanotubes are much more expensive than hexagonal boron nitride and are difficult to obtain in large quantities, which poses a problem in terms of production cost.

[0021] As described above, no techniques have been reported to date for efficiently reducing the particle size of scaly boron nitride particles.

[0022] The present inventors have investigated techniques for efficiently reducing the particle size of scaly boron nitride particles, and have found that attaching a compound having a specific structure to the surfaces of scaly boron nitride secondary particles promotes deagglomeration of the scaly boron nitride secondary particles, thereby efficiently producing small scaly boron nitride particles, leading to the completion of the boron nitride material of the present disclosure, which has excellent thermal conductivity.

[0023] Boron Nitride Material One embodiment of the boron nitride material of the present disclosure comprises two or more hexagonal boron nitrides and a compound containing a carbazole ring attached to at least a portion of the surface of the two or more hexagonal boron nitrides, and the boron nitride material is in the form of a scale. Figure 1 is a diagram showing a schematic configuration of one embodiment of the boron nitride material of the present disclosure. Boron nitride material 10 comprises two or more hexagonal boron nitrides 1 and a compound containing a carbazole ring 2 attached to at least a portion of the surface of the two or more hexagonal boron nitrides 1.

[0024] In one embodiment of the boron nitride material 10, each of the two or more hexagonal boron nitride particles 1 has a scale-like shape. In this case, the hexagonal boron nitride 1 may be at least one type selected from the group consisting of scale-like boron nitride particles, i.e., scale-like boron nitride primary particles and scale-like boron nitride secondary particles. For ease of explanation, FIG. 1 illustrates the hexagonal boron nitride 1 as being a scale-like boron nitride primary particle. However, the boron nitride material 10 may also include hexagonal boron nitride 1 having a shape other than a scale-like shape.

[0025] One embodiment of the boron nitride material 10 is scaly boron nitride secondary particles formed by aggregation of scaly boron nitride primary particles. That is, the hexagonal boron nitride 1 is the scaly boron nitride primary particles, and the boron nitride material 10 is the scaly boron nitride secondary particles.

[0026] In one embodiment of the boron nitride material 10, as shown in Figure 1, the two or more hexagonal boron nitrides include a first hexagonal boron nitride and a second hexagonal boron nitride, and at least a portion of the surface of the first hexagonal boron nitride is in contact with at least a portion of the surface of the second hexagonal boron nitride. In this way, at least a portion of the surface of the first hexagonal boron nitride and at least a portion of the surface of the second hexagonal boron nitride overlap so as to be in contact with each other, thereby efficiently forming a scale-like shape. Note that the first hexagonal boron nitride and the second hexagonal boron nitride refer to two hexagonal boron nitrides included in the two or more hexagonal boron nitrides, which are in contact with each other at least a portion of their surfaces.

[0027] The boron nitride material of the present disclosure can be easily deagglomerated, efficiently producing small-sized scaly boron nitride particles, resulting in excellent thermal conductivity. Figure 2 is a schematic diagram illustrating one embodiment of the state in which the boron nitride material of the present disclosure is deagglomerated and reduced in size. The attachment of carbazole ring-containing compound 2 to at least a portion of the surface of boron nitride material 10 efficiently promotes deagglomeration, resulting in reduced-sized scaly boron nitride particles 15. It is presumed that this is because the surface modification with carbazole ring-containing compound 2 reduces the surface energy of the hexagonal boron nitride contained in boron nitride material 10, thereby promoting deagglomeration of boron nitride material 10 and resulting in reduced-sized scaly boron nitride particles 15.

[0028] [Hexagonal Boron Nitride] Generally, boron nitride includes hexagonal boron nitride (h-BN) having a graphite-type layered structure, diamond-type cubic boron nitride (c-BN), and amorphous boron nitride (a-BN). In the present disclosure, hexagonal boron nitride (h-BN) having a graphite-type layered structure is used as the boron nitride. Hexagonal boron nitride has a layered structure similar to graphite, can be synthesized relatively easily, and can have particularly excellent properties such as thermal conductivity, heat dissipation, and electrical insulation.

[0029] Hexagonal boron nitride particles can be used as the hexagonal boron nitride contained in the boron nitride material of the present disclosure. Hexagonal boron nitride particles are usually white. Any appropriate shape can be adopted as the hexagonal boron nitride particles as long as the effects of the present disclosure are not impaired. The shape of the hexagonal boron nitride particles can be, for example, scaly, spherical, oval, or rod-like. In terms of further exhibiting the effects of the present disclosure, the hexagonal boron nitride contained in the boron nitride material of the present disclosure can be at least one type of scaly boron nitride particle selected from the group consisting of scaly boron nitride primary particles and scaly boron nitride secondary particles.

[0030] The average particle size of the hexagonal boron nitride particles may be any appropriate average particle size as long as it does not impair the effects of the present disclosure. The average particle size of the hexagonal boron nitride particles may be, for example, 0.05 μm or more and 100 μm or less, and may be 0.1 μm or more and 50 μm or less. In the present disclosure, the average particle size of the hexagonal boron nitride particles refers to the median diameter. The median diameter refers to the particle size (d50) when the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured, for example, using a laser diffraction measurement device.

[0031] [Compounds Containing Carbazole Rings] Compounds containing carbazole rings are attached to at least a portion of the surface of a boron nitride material, specifically to the surface of hexagonal boron nitride, and preferably to the surface of hexagonal boron nitride particles (i.e., scaly boron nitride particles). Carbazole rings are electron-rich heteroaromatic rings with high planarity. Therefore, compounds containing carbazole rings are suitable for modifying the surface of hexagonal boron nitride, which has a planar structure. Furthermore, compounds containing carbazole rings also have excellent properties such as chemical stability and heat resistance. That is, compounds containing carbazole rings serve to modify the surface of hexagonal boron nitride and can function as a surface modifier for hexagonal boron nitride.

[0032] The compound containing a carbazole ring may have a substituent at the 9-position of the carbazole ring, for example, to further enhance the effects of the present disclosure. Any appropriate substituent may be employed as such a substituent, provided that the effects of the present disclosure are not impaired. Examples of such a substituent include at least one selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group. The use of such a substituent may enable the compound containing a carbazole ring to exhibit high solubility in a solvent. This is believed to be due to weakened intermolecular forces between compounds containing a carbazole ring. The use of such a substituent may also weaken the intermolecular forces between compounds containing a carbazole ring, even in compounds containing a carbazole ring attached to the surface of a boron nitride material, thereby facilitating deagglomeration of the boron nitride material.

[0033] Examples of the aliphatic hydrocarbon group include saturated aliphatic hydrocarbon groups and unsaturated aliphatic hydrocarbon groups.

[0034] As the aliphatic saturated hydrocarbon group, any appropriate aliphatic saturated hydrocarbon group may be adopted as long as the effects of the present disclosure are not impaired. Examples of such aliphatic saturated hydrocarbon groups include linear aliphatic saturated hydrocarbon groups and branched aliphatic saturated hydrocarbon groups, and specific examples thereof include -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH(CH3)CH2CH3, -C(CH3)3, -CH2CH(CH3)2, -(CH2)3CH3, -(CH2)4CH3, -C(CH2CH3)(CH3)2, -CH2C(CH3)3, -(CH2)5CH3, -(CH2)6CH3, -(CH2)7CH3, -(CH2)8CH3, -(CH2)9CH3, -(CH2) 10 CH3, -(CH2) 11 CH3, -(CH2) 12 CH3, -(CH2) 13 CH3, -(CH2) 14 CH3, -(CH2) 15 CH3, -(CH2) 16 CH3, -(CH2) 17 CH3, -(CH2) 18 CH3, and -(CH2) 19 The aliphatic saturated hydrocarbon group may have any suitable number of carbon atoms as long as the effects of the present disclosure are not impaired. From the viewpoint of increasing the solubility of a compound containing a carbazole ring and reducing the amount of solvent used during surface modification of hexagonal boron nitride, the number of carbon atoms may be, for example, 1 to 20, or may be 1 to 10, or may be 1 to 5.

[0035] As the aliphatic unsaturated hydrocarbon group, any appropriate aliphatic unsaturated hydrocarbon group may be employed as long as the effects of the present disclosure are not impaired. Examples of such aliphatic unsaturated hydrocarbon groups include linear aliphatic unsaturated hydrocarbon groups and branched aliphatic unsaturated hydrocarbon groups, and specific examples include -CH=CH2, -C≡CH, -C≡CCH3, -C(CH3)=CH2, -CH=CHCH3, and -CH2CH=CH2. As the number of carbon atoms in the aliphatic unsaturated hydrocarbon group, any appropriate number of carbon atoms may be employed as long as the effects of the present disclosure are not impaired. The number of carbon atoms is, for example, from the viewpoint of increasing the solubility of a compound containing a carbazole ring and reducing the amount of solvent used during surface modification of hexagonal boron nitride, and may be, for example, from the viewpoint of reducing the amount of solvent used during surface modification of hexagonal boron nitride.

[0036] Examples of the alicyclic hydrocarbon group include an alicyclic saturated hydrocarbon group and an alicyclic unsaturated hydrocarbon group.

[0037] As the alicyclic saturated hydrocarbon group, any appropriate alicyclic saturated hydrocarbon group may be adopted as long as the effects of the present disclosure are not impaired. Examples of such alicyclic saturated hydrocarbon groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and an adamantyl group. As the number of carbon atoms in the alicyclic saturated hydrocarbon group, any appropriate number of carbon atoms may be adopted as long as the effects of the present disclosure are not impaired. The number of carbon atoms may be, for example, 1 or more and 20 or less, or may be 1 or more and 10 or less, or may be 1 or more and 5 or less, from the viewpoint of increasing the solubility of a compound containing a carbazole ring and reducing the amount of solvent used during surface modification of hexagonal boron nitride.

[0038] As the alicyclic unsaturated hydrocarbon group, any appropriate alicyclic unsaturated hydrocarbon group can be adopted as long as the effects of the present disclosure are not impaired. Examples of such alicyclic unsaturated hydrocarbon groups include a 1-cyclobutenyl group, a 2-cyclobutenyl group, a 1,3-cyclobutadienyl group, a 1-cyclopentenyl group, a 2-cyclopentenyl group, a 3-cyclopentenyl group, a 1,3-cyclopentadienyl group, a 2,4-cyclopentadienyl group, a 1-cyclohexenyl group, a 2-cyclohexenyl group, a 3-cyclohexenyl group, a 1,3-cyclohexadienyl group, a 1,4-cyclohexadienyl group, a 2,4-cyclohexadienyl group, a 2,5-cyclohexadienyl group, and a norbornenyl group. The number of carbon atoms in the alicyclic unsaturated hydrocarbon group can be any appropriate number of carbon atoms as long as the effects of the present disclosure are not impaired. The number of carbon atoms is, for example, from the viewpoint of increasing the solubility of the compound containing a carbazole ring and reducing the amount of solvent used during surface modification of hexagonal boron nitride, 1 or more and 20 or less, or 1 or more and 10 or less, or 1 or more and 5 or less.

[0039] Examples of halogenated aliphatic hydrocarbon groups include halogenated saturated aliphatic hydrocarbon groups and halogenated aliphatic unsaturated hydrocarbon groups.

[0040] Examples of such halogenated aliphatic hydrocarbon groups include the aforementioned aliphatic hydrocarbon groups in which at least one hydrogen atom has been substituted with a halogen atom, such as an F atom, a Cl atom, a Br atom, or an I atom.

[0041] Examples of halogenated alicyclic hydrocarbon groups include halogenated saturated alicyclic hydrocarbon groups and halogenated unsaturated alicyclic hydrocarbon groups.

[0042] Examples of such halogenated alicyclic hydrocarbon groups include groups in which at least one hydrogen atom contained in the above-mentioned alicyclic hydrocarbon groups has been substituted with a halogen atom, such as an F atom, a Cl atom, a Br atom, or an I atom.

[0043] Examples of halogen groups include F, Cl, Br, and I groups.

[0044] One embodiment of the substituent includes at least one selected from the group consisting of an aliphatic unsaturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group. These substituents are reactive substituents, and when such a substituent is employed, it can react with any compound on the surface of the boron nitride material, thereby controlling the surface state of the boron nitride material. Furthermore, when such a substituent is employed, when the boron nitride material is mixed with a resin to prepare a resin composition, the performance of the resin composition can be improved by reacting with the resin.

[0045] One embodiment of the compound containing a carbazole ring is represented by general formula (1). A compound having a carbazole ring in the main chain skeleton, such as that represented by general formula (1), results in a polymer with a more planar secondary structure than a compound having a carbazole ring in a side chain. Therefore, a compound having a carbazole ring in the main chain skeleton is suitable for modifying the surface of hexagonal boron nitride having a planar structure, typically scaly boron nitride particles, and preferably scaly boron nitride primary particles.

[0046]

[0047] In the general formula (1), n ​​represents a positive integer, for example, 1 or 1 to 1000.

[0048] In the general formula (1), a and b each independently represent an integer of 0 to 3.

[0049] In general formula (1), X is a single bond or at least one group selected from the group consisting of a divalent hydrocarbon group, a divalent halogenated hydrocarbon group, a divalent oxygen atom-containing group, a divalent nitrogen atom-containing group, a divalent sulfur atom-containing group, a divalent silicon atom-containing group, a divalent phosphorus atom-containing group, and a divalent boron atom-containing group.

[0050] As the divalent hydrocarbon group that X can represent, any appropriate divalent hydrocarbon group can be adopted as long as the effects of the present disclosure are not impaired. Examples of such divalent hydrocarbon groups include alkanediyl groups having 1 to 20 carbon atoms, alkenediyl groups having 1 to 20 carbon atoms, and divalent hydrocarbon groups containing an aromatic hydrocarbon ring. Examples of alkanediyl groups having 1 to 20 carbon atoms include methylene, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,2-diyl, propane-2,2-diyl, propane-1,3-diyl, 2-methylpropane-1,3-diyl, butane-1,3-diyl, butane-2,3-diyl, and butane-1,4-diyl. Examples of alkenediyl groups having 1 to 20 carbon atoms include ethene-1,2-diyl, 1-propene-1,3-diyl, 2-butene-1,4-diyl, 1-methyl-1-butene-1,4-diyl, and 2-cyclohexene-1,4-diyl. Examples of divalent hydrocarbon groups containing an aromatic hydrocarbon ring include those in which a portion of the aforementioned alkanediyl groups is replaced with an aromatic hydrocarbon ring, those in which a portion of the aforementioned alkenediyl groups is replaced with an aromatic hydrocarbon ring, and divalent hydrocarbon groups consisting solely of an aromatic hydrocarbon ring. Examples of such aromatic hydrocarbon rings include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring.

[0051] Any appropriate divalent halogenated hydrocarbon group may be employed as the divalent halogenated hydrocarbon group that can be represented by X, as long as the effects of the present disclosure are not impaired. Examples of such divalent halogenated hydrocarbon groups include the above-mentioned divalent hydrocarbon groups in which at least one hydrogen atom is substituted with a halogen atom.

[0052] As the divalent oxygen atom-containing group that X can take, any suitable divalent oxygen atom-containing group can be adopted as long as it does not impair the effects of the present disclosure. Examples of such divalent oxygen atom-containing groups include oxygen atoms (ether groups), ester groups, carbonyl groups, and divalent oxygen-containing aromatic heterocyclic groups. Examples of the oxygen-containing aromatic heterocycles that constitute the divalent oxygen-containing aromatic heterocyclic groups include furan rings and benzofuran rings.

[0053] As the divalent nitrogen atom-containing group that X can take, any suitable divalent nitrogen atom-containing group can be adopted as long as it does not impair the effects of the present disclosure. Examples of such divalent nitrogen atom-containing groups include imino groups and divalent nitrogen-containing aromatic heterocyclic groups. Examples of the nitrogen-containing aromatic heterocycle that constitutes the divalent nitrogen-containing aromatic heterocyclic group include pyrrole rings, pyrazole rings, imidazole rings, pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, indole rings, benzimidazole rings, quinoline rings, and isoquinoline rings.

[0054] As the divalent sulfur atom-containing group that X can take, any appropriate divalent sulfur atom-containing group can be adopted as long as it does not impair the effects of the present disclosure. Examples of such divalent sulfur atom-containing groups include sulfide groups, sulfinyl groups, sulfonyl groups, and divalent sulfur-containing aromatic heterocyclic groups. Examples of sulfur-containing aromatic heterocycles that constitute divalent sulfur-containing aromatic heterocyclic groups include thiophene rings and benzothiophene rings.

[0055] As the divalent silicon atom-containing group, divalent phosphorus atom-containing group, and divalent boron atom-containing group that X can take, any appropriate divalent silicon atom-containing group, divalent phosphorus atom-containing group, and divalent boron atom-containing group can be adopted, respectively, within a range that does not impair the effects of the present disclosure.

[0056] One exemplary embodiment of X is a single bond.

[0057] In general formula (1), R 1is at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group. The above description of the substituent located at the 9-position of the carbazole ring can be applied to these substituents.

[0058] In general formula (1), R 2 , R 3 , R 4 , and R 5 are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group.

[0059] R 2 , R 3 , R 4 , and R 5 Examples of hydrocarbon groups that may be included include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and hydrocarbon groups containing an aromatic hydrocarbon ring. Among these, the above-mentioned explanation of the substituent at the 9-position of the carbazole ring can be applied to the aliphatic hydrocarbon groups and alicyclic hydrocarbon groups. Examples of hydrocarbon groups containing an aromatic hydrocarbon ring include those in which a portion of the above-mentioned aliphatic hydrocarbon groups is replaced with an aromatic hydrocarbon ring, those in which a portion of the above-mentioned alicyclic hydrocarbon groups is replaced with an aromatic hydrocarbon ring, and hydrocarbon groups consisting only of an aromatic hydrocarbon ring. Examples of such aromatic hydrocarbon rings include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring.

[0060] R 2 , R 3 , R 4 , and R 5Examples of halogenated hydrocarbon groups that may be included include halogenated aliphatic hydrocarbon groups, halogenated alicyclic hydrocarbon groups, and halogenated hydrocarbon groups containing an aromatic hydrocarbon ring.Of these, the above-mentioned explanation of the substituent at the 9-position of the carbazole ring can be applied to halogenated aliphatic hydrocarbon groups and halogenated alicyclic hydrocarbon groups.Examples of halogenated hydrocarbon groups containing an aromatic hydrocarbon ring include those in which a portion of the halogenated aliphatic hydrocarbon group is replaced with an aromatic hydrocarbon ring, those in which a portion of the halogenated alicyclic hydrocarbon group is replaced with an aromatic hydrocarbon ring, and halogenated hydrocarbon groups consisting only of a halogenated aromatic hydrocarbon ring in which at least one hydrogen atom in the aromatic hydrocarbon ring is replaced with a halogen atom.Examples of halogen atoms include F atom, Cl atom, Br atom, and I atom.

[0061] R 2 , R 3 , R 4 , and R 5 The halogen group which may be taken by may be the same as that described above for the substituent at the 9-position of the carbazole ring.

[0062] R 2 , R 3 , R 4 , and R 5 As the oxygen atom-containing group that may be taken by the group, any appropriate oxygen atom-containing group may be adopted as long as the effects of the present disclosure are not impaired. Examples of such oxygen atom-containing groups include a hydroxyl group, a carboxyl group, an aldehyde group, and an acyl group.

[0063] R 2 , R 3 , R 4 , and R 5 As the nitrogen atom-containing group that may be taken by the compound (I), any appropriate nitrogen atom-containing group may be adopted as long as the effects of the present disclosure are not impaired. Examples of such nitrogen atom-containing groups include an amino group, a cyano group, an azido group, an amide group, a carbamate group, a nitro group, a cyanamide group, an isocyanate group, and an oxime group.

[0064] R 2 , R3 , R 4 , and R 5 As the sulfur atom-containing group that may be taken by the group, any appropriate sulfur atom-containing group can be adopted as long as the effects of the present disclosure are not impaired. Examples of such sulfur atom-containing groups include a thiol group, a sulfino group, a sulfonic acid group, an acylthio group, a sulfenamide group, a sulfonamide group, a thioamide group, a thiocarbamide group, and a thiocyano group.

[0065] R 2 , R 3 , R 4 , and R 5 As the silicon atom-containing group that may be taken by the compound (I), any appropriate silicon atom-containing group may be adopted as long as the effects of the present disclosure are not impaired. Examples of such silicon atom-containing groups include silyl groups and siloxy groups.

[0066] R 2 , R 3 , R 4 , and R 5 As the phosphorus atom-containing group that can be taken by the compound (I), any appropriate phosphorus atom-containing group can be adopted as long as the effects of the present disclosure are not impaired. Examples of such phosphorus atom-containing groups include a phosphino group and a phosphoryl group.

[0067] R 2 , R 3 , R 4 , and R 5 As the boron atom-containing group that can be taken by the formula (I), any appropriate boron atom-containing group can be adopted as long as the effects of the present disclosure are not impaired. Examples of such boron atom-containing groups include boronic acid groups and hydrocarbon groups having a boronic acid group. The hydrocarbon group referred to here may be the same as the above-mentioned description of the substituent located at the 9-position of the carbazole ring.

[0068] R 2 , R 3 , R 4 , and R 5 One exemplary embodiment of is a hydrocarbon group.

[0069] Another embodiment of the compound containing a carbazole ring is represented by general formula (2).

[0070] In the general formula (2), n represents a positive integer, for example, 1 to 1000.

[0071] In the general formula (2), a, b, c, and d each independently represent an integer of 0 to 3.

[0072] In general formula (2), R 1 and R 4 are each independently at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group. The above description of the substituent located at the 9-position of the carbazole ring can be applied to these substituents.

[0073] In general formula (2), R 2 , R 3 , R 5 , R 6 , R 7 , and R 8 are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group. 2 , R 3 , R 4 , and R 5 The explanation given in the previous paragraphs can be used.

[0074] R 2 , R 3 , R 5 , R 6 , R 7 , and R 8 One exemplary embodiment of is a hydrocarbon group.

[0075] [Boron nitride material] As described above, the boron nitride material of the present disclosure contains two or more hexagonal boron nitride particles and has a scaly shape. A compound containing a carbazole ring is attached to at least a portion of the surface of the boron nitride material of the present disclosure. In other words, the boron nitride material of the present disclosure is hexagonal boron nitride surface-modified with a compound containing a carbazole ring.

[0076] The amount of the compound containing a carbazole ring attached to hexagonal boron nitride may be any appropriate amount as long as it does not impair the effects of the present disclosure. A smaller amount is desirable as long as it does not impair the effects of the present disclosure. The amount of the compound containing a carbazole ring attached to hexagonal boron nitride is, for example, 10% by mass or less, or may be 0.01% by mass or more and 10% by mass or less, or 0.75% by mass or more and 5% by mass or less, relative to the amount of hexagonal boron nitride. If the amount of the compound containing a carbazole ring attached to hexagonal boron nitride is too high, the thermal conductivity may decrease compared to hexagonal boron nitride alone, potentially impairing performance as a thermal dissipation filler. The lower limit of the amount of the compound containing a carbazole ring attached to hexagonal boron nitride is sufficient to sufficiently modify the surface of hexagonal boron nitride, and is, for example, 0.01% by mass or more, as described above.

[0077] The boron nitride material of the present disclosure can be produced by any appropriate method as long as the effects of the present disclosure are not impaired. One embodiment of such a production method includes, for example, dissolving a compound containing a carbazole ring in a solvent to form a solution, mixing the solution with hexagonal boron nitride to perform surface modification of the hexagonal boron nitride, and filtering, washing, and drying the solid product to produce the boron nitride material of the present disclosure.

[0078] In the above-described manufacturing method, any appropriate mixing method can be adopted as a method for mixing the solution containing the compound containing a carbazole ring with hexagonal boron nitride, as long as the effects of the present disclosure are not impaired.

[0079] In the above-described manufacturing method, the temperature at which the solution containing the carbazole ring-containing compound is mixed with hexagonal boron nitride to perform surface modification of the hexagonal boron nitride may be any appropriate temperature within a range that does not impair the effects of the present disclosure. Such a temperature may be, for example, 5°C or higher and 95°C or lower, 5°C or higher and 80°C or lower, 5°C or higher and 60°C or lower, 5°C or higher and 50°C or lower, or 5°C or higher and 40°C or lower. Such a temperature may be, for example, room temperature (20°C±15°C).

[0080] In the above-described production method, any appropriate solvent may be used as the solvent as long as it does not impair the effects of the present disclosure.

[0081] <<Filler>> The filler of the present disclosure includes the boron nitride material of the present disclosure. The filler of the present disclosure may be the boron nitride material of the present disclosure itself, or may contain other components.

[0082] Thermally Dissipating Gap Filler One embodiment of the filler of the present disclosure is a thermally dissipating gap filler that includes the boron nitride material of the present disclosure.

[0083] In this disclosure, a thermally dissipating gap filler is a filler that is applied to electronic components such as substrate materials to fill air pockets or gaps, thereby dissipating heat from the electronic components. The thermally dissipating gap filler is a curing-type thermally dissipating paste that hardens from a paste state into a sheet state. The thermally dissipating gap filler of the present disclosure can improve the heat resistance of a resin composition containing it.

[0084] The thermally dissipating gap filler of the present disclosure can be produced, for example, by kneading the boron nitride material of the present disclosure with an epoxy resin or a silicone-based resin, or a non-silicone acrylic resin or a ceramic-based resin.

[0085] <Filler for Thermal Grease> Another embodiment of the filler of the present disclosure is a filler for thermal grease, which includes the boron nitride material of the present disclosure.

[0086] In this disclosure, the term "thermal grease filler" refers to a filler used in thermal grease. Thermal grease is a thermal paste that is applied to electronic components such as circuit board materials to fill air pockets or gaps, thereby dissipating heat from the electronic components. The thermal grease filler of this disclosure can improve the heat resistance of the filler.

[0087] The thermal grease filler of the present disclosure can be produced, for example, by kneading the boron nitride material of the present disclosure with an epoxy resin or a silicone-based resin, or a non-silicone acrylic resin or a ceramic-based resin.

[0088] Resin Composition The resin composition of the present disclosure includes the filler of the present disclosure. Because the resin composition of the present disclosure includes the filler of the present disclosure, it can exhibit high thermal conductivity, excellent heat dissipation properties, and excellent electrical insulation properties without reducing mechanical properties such as flexibility.

[0089] 3 is a diagram showing a schematic configuration of one embodiment of the resin composition of the present disclosure. The resin composition 20 includes, for example, a filler 22 and a curable resin 24.

[0090] Filler 22 includes boron nitride material 10 of the present disclosure. Filler 22 may consist solely of boron nitride material 10 of the present disclosure, or may contain other filler materials, such as silica particles, in combination with boron nitride material 10 of the present disclosure.

[0091] Examples of the curable resin 24 include epoxy resins, cyanate ester compounds, maleimide compounds, phenolic resins, acrylic resins, polyamide resins, polyamideimide resins, thermosetting polyimide resins, and polyphenylene ether resins. Only one type of curable resin 24 may be used, or two or more types may be used in combination.

[0092] The resin composition 20 may contain other components. Examples of the other components include a curing agent, a flame retardant, an ultraviolet absorber, an antioxidant, a reaction initiator, a silane coupling agent, a fluorescent brightener, a photosensitizer, a dye, a pigment, a thickener, a lubricant, an antifoaming agent, a dispersant, a leveling agent, a gloss agent, an antistatic agent, a polymerization inhibitor, and an organic solvent. Only one of the other components may be used, or two or more may be used in combination.

[0093] <Film with Resin Layer> The film with a resin layer of the present disclosure includes a resin layer containing the resin composition of the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a support film. The film with a resin layer of the present disclosure is suitable for, for example, an insulating layer.

[0094] The semi-cured resin composition of the present disclosure refers to a material in a partially cured state to the extent that the resin composition of the present disclosure can be further cured. That is, the semi-cured resin composition of the present disclosure is a material in a semi-cured state of the resin composition of the present disclosure. In one embodiment of the resin composition of the present disclosure, when heated, its viscosity gradually decreases, and as heating continues, curing then begins and its viscosity gradually increases. In such a case, the semi-cured state of the resin composition of the present disclosure can be the state of the resin composition of the present disclosure from the time when the viscosity starts to increase to the time when it is completely cured.

[0095] The resin composition of the present disclosure may be cured by any suitable method as long as the effects of the present disclosure are not impaired. Examples of such a curing method include a thermosetting reaction.

[0096] The curing temperature during the thermosetting reaction may be set to any appropriate temperature depending on the composition or purpose of the resin composition of the present disclosure, and may be, for example, 40°C to 300°C.

[0097] Fig. 4 is a schematic cross-sectional view of one embodiment of the resin layer-included film of the present disclosure. The resin layer-included film 30 of the present disclosure includes a resin layer 32 containing the resin composition of the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a support film 34. The resin layer 32 is supported by the support film 34. In the embodiment shown in Fig. 4, the support film 34 is disposed on the surface of the resin layer 32. Note that another layer, such as an adhesive layer, may be provided between the resin layer 32 and the support film 34.

[0098] The resin layer 32 may include a fibrous base material. Any appropriate fibrous base material may be used as the fibrous base material as long as the effects of the present disclosure are not impaired. Examples of such fibrous base materials include known materials used in various types of laminates for electrical insulating materials. Examples of such fibrous base materials include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper.

[0099] The resin layer 32 can be an insulating layer either as it is or after curing, such as an insulating layer of a wiring board.

[0100] Any suitable support film may be used as the support film as long as the effects of the present disclosure are not impaired. Examples of such a support film include resin films such as polyethylene terephthalate films.

[0101] The resin layer-attached metal foil of the present disclosure includes a resin layer containing the resin composition of the present disclosure, a semi-cured product thereof, or a cured product thereof, and a metal foil. The resin layer-attached metal foil of the present disclosure can be used as a resin layer-attached metal foil suitable for electronic circuit components such as wiring boards.

[0102] The above-described explanation of the resin layer-attached film may be applied to the semi-cured product of the resin composition of the present disclosure and the cured product of the resin composition of the present disclosure.

[0103] Fig. 5 is a schematic cross-sectional view of one embodiment of the resin layer-provided metal foil of the present disclosure. The resin layer-provided metal foil 40 of the present disclosure includes a resin layer 42 containing the resin composition of the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a metal foil 44. The resin layer 42 is supported by the metal foil 44. In the embodiment shown in Fig. 5, the metal foil 44 is disposed on the surface of the resin layer 42. Note that another layer, such as an adhesive layer, may be provided between the resin layer 42 and the metal foil 44.

[0104] The resin layer may contain a fibrous substrate. The description of the fibrous substrate that may be contained in the resin layer-attached film may be used as the fibrous substrate. The resin layer may become an insulating layer as it is or after curing. An example of such an insulating layer is, for example, an insulating layer of a wiring board.

[0105] As the metal foil, any appropriate metal foil can be used as long as it does not impair the effects of the present disclosure. Examples of such metal foils include copper foil and aluminum foil.

[0106] <Prepreg> The prepreg of the present disclosure contains the resin composition of the present disclosure or a semi-cured product thereof.

[0107] For the semi-cured product of the resin composition of the present disclosure, the above description of the film with a resin layer can be applied.

[0108] The prepreg of the present disclosure typically includes a fibrous substrate. The fibrous substrate may be present in a matrix of the resin composition of the present disclosure or a semi-cured product thereof. The prepreg of the present disclosure may be a composite material of the resin composition of the present disclosure or a semi-cured product thereof and the fibrous substrate. The prepreg of the present disclosure having such a configuration may be suitable for high-frequency wiring boards.

[0109] As for the fibrous base material, the description of the fibrous base material that can be contained in the resin layer-attached film can be used.

[0110] In the prepreg of the present disclosure, the resin composition of the present disclosure or a semi-cured product thereof can be impregnated into a fibrous substrate by treatment such as immersion, coating, etc. By heating the fibrous substrate impregnated with the resin composition of the present disclosure or a semi-cured product thereof under predetermined heating conditions, a prepreg of the present disclosure in an uncured or semi-cured state can be obtained.

[0111] <Metal-clad laminate> One embodiment of the metal-clad laminate of the present disclosure includes an insulating layer containing a cured product of the resin composition of the present disclosure and a metal foil. Another embodiment of the metal-clad laminate of the present disclosure includes an insulating layer containing a cured product of the prepreg of the present disclosure and a metal foil. The metal-clad laminate of the present disclosure can be, for example, a metal-clad laminate suitable for wiring boards.

[0112] For the cured product of the resin composition of the present disclosure, the above description of the film with a resin layer may be applied.

[0113] Figure 6 is a schematic cross-sectional view of one embodiment of a metal-clad laminate according to the present disclosure. The metal-clad laminate 50 includes an insulating layer 52 and at least one metal foil 54. The insulating layer 52 includes a cured product of the resin composition according to the present disclosure or a cured product of the prepreg according to the present disclosure. The metal foil 54 is disposed on the surface of the insulating layer 52. In the example shown in Figure 6, metal foils 54 are disposed on both the front and back surfaces of the insulating layer 52.

[0114] A typical embodiment of the metal-clad laminate of the present disclosure is manufactured using the prepreg of the present disclosure. The metal-clad laminate of the present disclosure is manufactured, for example, by stacking 1 to 20 prepregs to form a laminate, placing metal foil on one or both sides of the resulting prepreg laminate, and applying heat and pressure to produce the metal-clad laminate of the present disclosure.

[0115] As the metal foil, any appropriate metal foil can be used as long as it does not impair the effects of the present disclosure. Examples of such metal foils include copper foil and aluminum foil.

[0116] As the molding conditions for producing the metal-clad laminate of the present disclosure, any appropriate molding conditions can be adopted as long as the effects of the present disclosure are not impaired. For example, molding conditions generally adopted for producing laminates for electrical insulating materials and multilayer boards can be applied.

[0117] <<Wiring Board>> One embodiment of the wiring board of the present disclosure includes an insulating layer containing a cured product of the resin composition of the present disclosure, and wiring. Another embodiment of the wiring board of the present disclosure includes an insulating layer containing a cured product of the prepreg of the present disclosure, and wiring. The wiring board of the present disclosure can be, for example, a wiring board suitable for high frequencies.

[0118] For the cured product of the resin composition of the present disclosure, the above description of the film with a resin layer may be applied.

[0119] 7 is a schematic cross-sectional view of one embodiment of a wiring board according to the present disclosure. The wiring board 60 according to the present disclosure includes an insulating layer 62 and wiring 64. The insulating layer 62 includes a cured product of the resin composition according to the present disclosure or a cured product of the prepreg according to the present disclosure. The wiring 64 is supported by the insulating layer 62. The wiring 64 is typically disposed on the insulating layer 62. The wiring 64 can be formed, for example, by partially removing the metal foil. For example, by patterning the metal foil on the surface of the metal-clad laminate according to the present disclosure by a method such as etching, a wiring board 60 having wiring 64 forming a circuit on the surface of the insulating layer 62 can be obtained.

[0120] A new laminate may be formed by laminating the prepreg of the present disclosure on at least one surface of the wiring board of the present disclosure, and then applying heat and pressure. A multilayer wiring board can be obtained by patterning the metal foil on the surface of the resulting laminate to form wiring.

[0121] <Heat Conductive Material> The heat conductive material of the present disclosure includes a semi-cured product or a cured product of the resin composition of the present disclosure.

[0122] The above-described explanation of the resin layer-attached film may be applied to the semi-cured product of the resin composition of the present disclosure and the cured product of the resin composition of the present disclosure.

[0123] The thermally conductive material of the present disclosure may have any suitable shape as long as the effects of the present disclosure are not impaired. The thermally conductive material of the present disclosure may be, for example, in the form of a sheet. In this case, the thermally conductive material of the present disclosure may be a thermally conductive sheet. Alternatively, the thermally conductive material of the present disclosure may be a thermally conductive insulating composition.

[0124] The thermally conductive material of the present disclosure can be applied to heat dissipation materials such as heat dissipation sheets, etc. Specifically, by placing a thermally conductive layer including the thermally conductive material of the present disclosure on a device, heat generated from the device can be efficiently dissipated through the thermally conductive layer.

[0125] The thermally conductive material of the present disclosure may also be employed in heat dissipation applications for power semiconductor devices, for example.

[0126] When the thermally conductive material of the present disclosure has adhesive properties, it can also be used as a thermally conductive adhesive.

[0127] The thermally conductive material of the present disclosure may be used in combination with other members, such as sheet-like supports, including, for example, plastic films, metal films, and glass plates.

[0128] The thermally conductive materials of the present disclosure also include heat dissipation sealants, heat dissipation insulating plates, thermally conductive putties, phase change materials (PCMs), and heat dissipation double-sided tapes.

[0129] <<Additional Notes>> Based on the above description, the following techniques are disclosed.

[0130] (Technology 1) A boron nitride material comprising two or more hexagonal boron nitrides and a compound containing a carbazole ring attached to at least a portion of the surface of the two or more hexagonal boron nitrides, wherein the boron nitride material is shaped like a scale, and each of the two or more hexagonal boron nitrides is shaped like a scale.

[0131] (Technology 2) The two or more hexagonal boron nitrides include a first hexagonal boron nitride and a second hexagonal boron nitride, and at least a portion of a surface of the first hexagonal boron nitride is in contact with at least a portion of a surface of the second hexagonal boron nitride. The boron nitride material according to Technology 1.

[0132] (Technology 3) The boron nitride material according to Technology 1 or Technology 2, wherein the compound containing the carbazole ring has a substituent at the 9-position of the carbazole ring.

[0133] (Technology 4) The boron nitride material according to Technology 3, wherein the substituent is at least one selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group.

[0134] (Technology 5) The boron nitride material according to any one of Technology 1 to Technology 4, wherein the compound containing a carbazole ring is represented by general formula (1). In general formula (1), n ​​represents a positive integer, a and b each independently represent an integer of 0 to 3, X represents a single bond or at least one group selected from the group consisting of a divalent hydrocarbon group, a divalent halogenated hydrocarbon group, a divalent oxygen atom-containing group, a divalent nitrogen atom-containing group, a divalent sulfur atom-containing group, a divalent silicon atom-containing group, a divalent phosphorus atom-containing group, and a divalent boron atom-containing group, and R 1 is at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group, and R 2 , R 3 , R 4 , and R 5are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group.

[0135] (Technology 6) The boron nitride material according to Technology 5, wherein X in the general formula (1) is a single bond.

[0136] (Technology 7) R in the general formula (1) 2 , R 3 , R 4 , and R 5 The boron nitride material according to Technology 5 or Technology 6, wherein is a hydrocarbon group.

[0137] (Technology 8) The boron nitride material according to any one of Technology 5 to Technology 7, wherein n in the general formula (1) is 1.

[0138] (Technology 9) The boron nitride material according to any one of Technology 1 to Technology 4, wherein the compound containing a carbazole ring is represented by general formula (2): In general formula (2), n represents a positive integer, a, b, c, and d each independently represent an integer of 0 to 3, and R 1 and R 4 are each independently at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group; R 2 , R 3 , R 5 , R 6 , R 7 , and R 8 are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group.

[0139] (Technology 10) R in the general formula (2) 2, R 3 , R 5 , R 6 , R 7 , and R 8 The boron nitride material according to claim 9, wherein is a hydrocarbon group.

[0140] (Technology 11) A filler comprising the boron nitride material according to any one of Technology 1 to Technology 10.

[0141] (Technology 12) A resin composition comprising the filler according to Technology 11.

[0142] (Technology 13) A film with a resin layer, comprising: the resin composition according to Technology 12; a resin layer containing a semi-cured product of the resin composition or a cured product of the resin composition; and a support film.

[0143] (Technology 14) A metal foil with a resin layer, comprising: the resin composition according to Technology 12; a resin layer containing a semi-cured product of the resin composition or a cured product of the resin composition; and a metal foil.

[0144] (Technology 15) A prepreg comprising the resin composition according to Technology 12 or a semi-cured product of the resin composition.

[0145] (Technology 16) A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to Technology 12, and a metal foil.

[0146] (Technology 17) A metal-clad laminate comprising an insulating layer containing a cured product of the prepreg according to Technology 15, and a metal foil.

[0147] (Technology 18) A wiring board comprising an insulating layer containing a cured product of the resin composition according to Technology 12 and wiring.

[0148] (Technology 19) A wiring board comprising an insulating layer containing a cured product of the prepreg according to Technology 15, and wiring.

[0149] (Technology 20) A thermally conductive material comprising a semi-cured product of the resin composition according to Technology 12 or a cured product of the resin composition.

[0150] The present disclosure will be specifically described below with reference to examples. The examples are intended to illustrate the present disclosure and are not intended to limit the scope of the present disclosure.

[0151] <Measurement of particle size distribution> The particle size distribution of the boron nitride materials obtained in the examples and comparative examples was measured using a laser diffraction particle size distribution analyzer (SALD-2300, manufactured by Shimadzu Corporation). A batch cell was used for the measurement, and the particle size distribution was measured in toluene with a refractive index of 2.20-0.05i, and the median diameter was confirmed by the measurement.

[0152] <Measurement of Number Average Molecular Weight by GPC> The number average molecular weights of Compounds A, B, and C used in the examples were measured using a gel permeation chromatograph (GPC) measuring device (HLC-8320GPC, manufactured by Tosoh Corporation). The detector of this GPC measuring device was a differential refractometer. Chloroform was used as the measurement solvent, and two TSKgel Super HM-H columns (manufactured by Tosoh Corporation) were used, at a flow rate of 0.6 mL / min and a column temperature of 40°C.

[0153] Example 1 100 mg of compound A was dissolved in 100 mL of chloroform, and 10 g of boron nitride (hexagonal boron nitride, manufactured by Denka, SGP grade), which is scaly boron nitride particles, was suspended therein. After the chloroform was distilled off under reduced pressure, the remaining powder was suspended in chloroform, isolated by suction filtration, and then washed with chloroform. This was then vacuum dried, yielding approximately 10 g of boron nitride material (1). The median diameter of the obtained boron nitride material (1) is shown in Table 2.

[0154]

[0155] The number average molecular weight of the compound A represented by formula (A) was found to be 5 by GPC measurement.

[0156] Example 2 100 mg of compound B was dissolved in 100 mL of chloroform, and 10 g of boron nitride (hexagonal boron nitride, manufactured by Denka, SGP grade), which is a scale-like boron nitride particle, was suspended therein. After the chloroform was distilled off under reduced pressure, the remaining powder was suspended in chloroform, isolated by suction filtration, and then washed with chloroform. This was then vacuum dried, yielding approximately 10 g of boron nitride material (2). The median diameter of the obtained boron nitride material (2) is shown in Table 2.

[0157]

[0158] The number average molecular weight of the compound B represented by formula (B) was found to be 11 by GPC measurement.

[0159] Example 3 100 mg of compound C was dissolved in 100 mL of chloroform, and 10 g of boron nitride (hexagonal boron nitride, manufactured by Denka, SGP grade), which is a scale-like boron nitride particle, was suspended therein. After the chloroform was distilled off under reduced pressure, the remaining powder was suspended in chloroform, isolated by suction filtration, and then washed with chloroform. This was then vacuum dried, yielding approximately 10 g of boron nitride material (3). The median diameter of the obtained boron nitride material (3) is shown in Table 2.

[0160]

[0161] The number average molecular weight of the compound C represented by formula (C) was found to be 3 by GPC measurement.

[0162] Example 4 100 mg of compound D was dissolved in 10 mL of toluene, and 10 g of boron nitride (hexagonal boron nitride, manufactured by Denka, SGP grade), which is a scale-like boron nitride particle, was suspended therein. After the toluene was distilled off under reduced pressure, the remaining powder was suspended in toluene, isolated by suction filtration, and washed with toluene. This was then vacuum dried, yielding approximately 10 g of boron nitride material (4). The median diameter of the obtained boron nitride material (4) is shown in Table 2.

[0163]

[0164] [Comparative Example 1] Boron nitride (hexagonal boron nitride, manufactured by Denka, SGP grade) itself, which is a scaly boron nitride particle, was used as a boron nitride material (C1). The median diameter of the boron nitride material (C1) is shown in Table 2.

[0165] Comparative Example 2 3.3 mL of a silane coupling agent (KBM-503, manufactured by Shin-Etsu Silicones Co., Ltd.) was dissolved in 70 mL of toluene, and 10 g of boron nitride (hexagonal boron nitride, manufactured by Denka Corporation, SGP grade), which is scaly boron nitride particles, was suspended therein. After stirring at 100°C for 3 hours, the powder was isolated by suction filtration and washed with toluene. The mixture was then dried by heating at 80°C for 20 minutes, yielding approximately 10 g of boron nitride material (C2). The median diameter of the boron nitride material (C2) is shown in Table 2.

[0166]

[0167] <<Discussion>> As shown in Table 2, the median diameters of the boron nitride materials obtained in Examples 1 to 4 were significantly smaller than those of the boron nitride materials obtained in Comparative Examples 1 and 2. This shows that the particle size of the boron nitride material of the present disclosure is significantly smaller due to its surface modification than that of boron nitride before surface modification. It is generally known that when anisotropic particles are deagglomerated, the particle size distribution of laser diffraction shifts overall to a smaller size, resulting in a smaller median diameter. Therefore, it is presumed that the surface modification of the boron nitride materials obtained in Examples 1 to 4 promotes deagglomeration of secondary particles, resulting in a smaller particle size.

[0168] As explained in the section "Knowledge Forming the Basis of the Present Disclosure," the inventors conducted heat transfer simulation studies and found that the smaller the particle size of the scaly boron nitride particles, the higher the thermal conductivity. Therefore, it can be seen that the boron nitride material of the present disclosure has excellent thermal conductivity. Furthermore, when blending boron nitride particles into a resin to prepare a resin composition, it can be seen that the pot life can be improved when the resin dissolved in a solution and the boron nitride particles are mixed to form a varnish, or when the liquid resin and the boron nitride particles are mixed to form a heat-dissipating paste.

[0169] As described above, in order to express the present disclosure, the present disclosure has been appropriately and sufficiently described through the embodiments, but it should be recognized that those skilled in the art can easily change and / or improve the above-described embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that deviates from the scope of the claims described in the claims, the changes or improvements are interpreted as being encompassed within the scope of the claims.

[0170] The boron nitride material of the present disclosure can provide a filler with excellent heat resistance, making it suitable for applications such as wiring boards for electronic devices used in high-capacity communications.

[0171] REFERENCE SIGNS LIST 1 Hexagonal boron nitride 2 Compound containing carbazole ring 10 Boron nitride material 15 Small particle size scaly boron nitride particles 20 Resin composition 22 Filler 24 Curable resin 30 Resin-attached film 32 Resin layer 34 Support film 40 Resin-attached metal foil 42 Resin layer 44 Metal foil 50 Metal-clad laminate 52 Insulating layer 54 Metal foil 60 Wiring board 62 Insulating layer 64 Wiring

Claims

1. A boron nitride material comprising: two or more hexagonal boron nitride particles; and a compound containing a carbazole ring attached to at least a portion of a surface of the two or more hexagonal boron nitride particles, wherein the boron nitride material is shaped like a flake; and each of the two or more hexagonal boron nitride particles is shaped like a flake.

2. The boron nitride material of claim 1, wherein the two or more hexagonal boron nitrides include a first hexagonal boron nitride and a second hexagonal boron nitride, and at least a portion of a surface of the first hexagonal boron nitride is in contact with at least a portion of a surface of the second hexagonal boron nitride.

3. The boron nitride material according to claim 1, wherein the compound containing a carbazole ring has a substituent at the 9-position of the carbazole ring.

4. The boron nitride material according to claim 3, wherein the substituent is at least one selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group.

5. The boron nitride material according to claim 1, wherein the compound containing a carbazole ring is represented by general formula (1). In general formula (1), n ​​represents a positive integer, a and b each independently represent an integer from 0 to 3, X represents a single bond or at least one group selected from the group consisting of a divalent hydrocarbon group, a divalent halogenated hydrocarbon group, a divalent oxygen atom-containing group, a divalent nitrogen atom-containing group, a divalent sulfur atom-containing group, a divalent silicon atom-containing group, a divalent phosphorus atom-containing group, and a divalent boron atom-containing group, and R 1 R is at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group; 2 , R 3 , R 4 , and R 5 are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group.

6. The boron nitride material according to claim 5, wherein X in said general formula (1) is a single bond.

7. R in the above general formula (1) 2 , R 3 , R 4 , and R 5 The boron nitride material of claim 5 , wherein: is a hydrocarbon group.

8. The boron nitride material according to claim 5, wherein n in said general formula (1) is 1.

9. The boron nitride material according to claim 1, wherein the compound containing a carbazole ring is represented by general formula (2). In the general formula (2), n represents a positive integer, a, b, c, and d each independently represent an integer of 0 to 3, 1 and R 4 are each independently at least one substituent selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, a halogenated aliphatic hydrocarbon group, a halogenated alicyclic hydrocarbon group, a halogen group, an acrylic group, a methacrylic group, an acyl group, an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a silanol group, and a thiol group; 2 , R 3 , R 5 , R 6 , R 7 , and R 8 are each independently at least one group selected from the group consisting of a hydrogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a halogen group, an oxygen atom-containing group, a nitrogen atom-containing group, a sulfur atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, and a boron atom-containing group.

10. R in the above general formula (2) 2 , R 3 , R 5 , R 6 , R 7 , and R 8 The boron nitride material of claim 9 , wherein: is a hydrocarbon group.

11. A filler comprising the boron nitride material according to any one of claims 1 to 10.

12. A resin composition comprising the filler according to claim 11.

13. A film with a resin layer, comprising: a resin layer containing the resin composition according to claim 12, a semi-cured product of said resin composition, or a cured product of said resin composition; and a support film.

14. A metal foil with a resin layer, comprising: a resin layer comprising the resin composition according to claim 12, a semi-cured product of said resin composition, or a cured product of said resin composition; and a metal foil.

15. A prepreg comprising the resin composition according to claim 12 or a semi-cured product of said resin composition.

16. A metal-clad laminate comprising an insulating layer comprising a cured product of the resin composition according to claim 12, and a metal foil.

17. A metal-clad laminate comprising an insulating layer comprising the cured product of the prepreg according to claim 15, and a metal foil.

18. A wiring board comprising an insulating layer containing a cured product of the resin composition according to claim 12, and wiring.

19. A wiring board comprising an insulating layer containing the cured product of the prepreg according to claim 15 and wiring.

20. A thermally conductive material comprising a semi-cured product of the resin composition according to claim 12 or a cured product of the resin composition.