WO2018230638A1 - Carbon-modified boron nitride, method for producing same, and highly heat-conductive resin composition - Google Patents

Carbon-modified boron nitride, method for producing same, and highly heat-conductive resin composition Download PDF

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WO2018230638A1
WO2018230638A1 PCT/JP2018/022717 JP2018022717W WO2018230638A1 WO 2018230638 A1 WO2018230638 A1 WO 2018230638A1 JP 2018022717 W JP2018022717 W JP 2018022717W WO 2018230638 A1 WO2018230638 A1 WO 2018230638A1
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boron nitride
carbon
graphene oxide
resin
modified boron
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PCT/JP2018/022717
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French (fr)
Japanese (ja)
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弘朗 在間
伊藤　玄
淳子 大仲
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株式会社Kri
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Priority claimed from JP2018106168A external-priority patent/JP6803874B2/en
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/064—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with boron
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/02—Ingredients treated with inorganic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds

Definitions

  • the present invention relates to a high thermal conductive material composed of boron nitride and a resin, and specifically to a surface-modified boron nitride.
  • nitrides such as boron nitride having no electrical conductivity and high thermal conductivity are expected.
  • the boron nitride surface has very few functional groups, the affinity with the resin is low. For this reason, there are problems that the dispersibility in the resin is poor, and that separation occurs at the interface between the boron nitride surface and the resin and voids are easily formed.
  • a silane coupling agent, an organic compound, or the like is reacted with an amino group or a hydroxyl group in boron nitride.
  • these groups are mainly present on the end face of the boron nitride crystal sheet having a layered structure similar to that of graphite, it is not very effective in improving the resin affinity on the boron nitride surface.
  • Patent Document 1 heating oxidation in air (Patent Document 1), surface oxidation using supercritical water or subcritical water (Patent Document 2), and introduction of amino groups by plasma treatment (Patent Document 1).
  • Patent Document 3 mechanochemical treatment
  • Patent Document 4 mechanochemical treatment
  • the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide boron nitride having good resin compatibility with energy saving, low cost.
  • Another object is to provide a high thermal conductive resin composition by mixing the carbon-modified boron nitride with a resin.
  • the carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the surface of boron nitride particles.
  • the sheet-like carbon layer is 1 to 20 layers of graphene oxide, or the sheet-like carbon layer is 1 to 20 layers of reduced graphene oxide.
  • the high thermal conductive resin composition of the present invention includes the above carbon-modified boron nitride and a resin.
  • the method for producing carbon-modified boron nitride particles of the present invention includes a step of mixing an aqueous graphene oxide dispersion and boron nitride powder, and collecting and drying a solid from the liquid obtained by the mixing, and carbon-modified boron nitride. Obtaining.
  • the method further includes the step of reducing the carbon-modified boron nitride with a reducing agent.
  • boron nitride having a sheet-like carbon layer on the particle surface can be provided with energy saving and low cost.
  • the affinity between boron nitride and the resin is improved, the fluidity of the blended resin composition and the interfacial adhesion between the boron nitride and the resin can be improved.
  • a heat conductive resin composition having no electrical conductivity and excellent mechanical strength and thermal conductivity.
  • the carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the surface of the boron nitride particles, and this sheet-like carbon layer has a function of improving the affinity between the resin and the boron nitride interface.
  • the sheet-like carbon layer is graphene oxide or reduced graphene oxide obtained by subjecting this graphene oxide to chemical reduction and / or physical reduction treatment by heating. Any known technique can be used for the reduction method, and there is no particular limitation.
  • the sheet-like carbon layer is graphene oxide or reduced graphene oxide obtained by reducing the sheet carbon layer can be selected depending on the properties of the resin mixed with the carbon-modified boron nitride.
  • the affinity for a resin to be mixed can be improved using these.
  • a method of use a method of chemically bonding these groups to a resin, a method of using physical interaction between these groups and a functional group in the resin molecule, an organic compound having good affinity with the resin for these groups, or Examples include a method of chemically bonding oligomers.
  • Graphene oxide obtained by oxidizing and exfoliating graphite using the Hammers method is a single layer graphene oxide, multi-layer graphene oxide composed of multiple layers of single-layer graphene oxide, and multi-layer oxidation with a non-oxidized layer inside It becomes a mixture of graphene. In this specification, all of these are referred to as graphene oxide. If such a mixture is used as it is, the sheet-like carbon layer becomes a layer in which single-layer to multi-layer graphene oxide is mixed.
  • the function of the sheet-like carbon layer is exhibited by 1 to 20 layers, preferably 1 to 10 layers, more preferably 1 to 7 layers of graphene oxide or reduced graphene oxide. If it exceeds 20 layers, the properties of graphite become dominant and the effects of the present invention may not be exhibited.
  • the number of layers of graphene oxide and reduced graphene oxide can be evaluated by, for example, an atomic force microscope, a transmission electron microscope, a Raman spectrum, or the like.
  • This coverage ratio can be estimated from X-ray photoelectron spectroscopy. Further, a micro Raman spectrum measurement of a plurality of points is performed, and the coverage ratio can be obtained by using a ratio of the number of points at which D or G bands derived from graphene oxide are observed to the total number of measurement points. Also in this case, the covering ratio is at least 0.2 or more, preferably 0.3 or more, more preferably 0.5 or more.
  • the sheet-like carbon layer is typically laminated by being adsorbed on boron nitride particles.
  • Boron nitride has various crystal structures such as hexagonal crystal and cubic crystal, and any of them can be used in the present invention.
  • hexagonal boron nitride powder is preferable because it is easily available industrially and is inexpensive.
  • the size of boron nitride is not particularly limited as long as it is generally suitable for use in the heat conduction field.
  • the average particle diameter is preferably 0.1 ⁇ m to 100 ⁇ m, more preferably 0.5 ⁇ m to 60 ⁇ m. When the average particle size is smaller than 0.1 ⁇ m, the fluidity of the resin composition obtained by strengthening the nanoparticle effect may be lowered.
  • the layer thickness in the case of forming a heat conductive layer from the obtained resin composition may not be sufficiently reduced.
  • an average particle diameter (d50) measured by a laser diffraction / scattering method can be adopted.
  • graphene oxide 0.01 w% to 5 w% aqueous dispersion obtained by oxidizing graphite using a known method known as the Hummers method and performing exfoliation treatment to 1 to 20 layers can be used.
  • the medium hydrophilic solvents such as alcohols such as methanol and ethanol, glycols such as ethylene glycol, tetrahydrofuran and the like can be added as long as graphene oxide is mainly agglomerated and does not aggregate.
  • the graphene oxide obtained has various shapes, but the general shape is a thin sheet with a shape close to a rectangle with irregularities around it, the size of which depends on the size of the raw graphite crystals To do.
  • the longest length of the existing sheet is the average particle size of boron nitride particles
  • the diameter is 1/1000 to 2/1, preferably 1/500 to 1/1, and more preferably 1/10 to 0.7 / 1. When it is out of the range of 1/1000 to 2/1, it is difficult to form a sheet-like carbon layer.
  • Carbon-modified boron nitride is dispersed in graphene oxide aqueous dispersion by adding boron nitride powder and stirring or using a powerful dispersing device such as a homogenizer as necessary, and then recovered from the dispersion by filtration or centrifugal sedimentation. Then, it can obtain as a powder by drying at room temperature or heat-drying as needed.
  • boron nitride powder is dispersed in an aqueous graphene oxide dispersion, precipitation occurs and the color of the supernatant (graphene oxide aqueous dispersion layer) becomes lighter. Finally, the supernatant becomes colorless and transparent, and graphene oxide is not detected from the supernatant.
  • the amount of boron nitride added to the graphene oxide aqueous dispersion can be arbitrarily selected depending on how much boron nitride is adsorbed on the surface of the boron nitride particles.
  • the sheet-like carbon layer can be converted into reduced graphene oxide by chemical reduction in which the dispersion or the dried product is reduced with a reducing agent, or heat reduction in which the dried product is heat-treated.
  • a reducing agent for chemical reduction known ones can be used.
  • hydrazine, hydrazine reducing agents such as hydrazine compounds such as hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate, sodium borohydride, sodium sulfite, Sodium bisulfite, sodium thiosulfate, sodium nitrite, sodium hyponitrite, phosphorous acid and its salts such as sodium phosphite, hypophosphorous acid and its salts such as sodium hypophosphite, hydrogen iodide, ascorbine
  • phosphorous acid and its salts such as sodium phosphite, hypophosphorous acid and its salts such as sodium hypophosphite, hydrogen iodide, ascorbine
  • acids include acids, alcohols such as ethanol, glycols such as ethylene glycol, and the like, and one or more of these can be used.
  • the amount used is preferably 0.1 to 50 times, preferably 0.5 to 30 times, more preferably 1 to 20 times the weight of graphene oxide. If the total amount of the reducing agent is less than the above range, the reaction may not proceed easily, and if it exceeds the above range, it may take time to remove from the system.
  • the reduction time is 1 hour to 72 hours when the reduction is performed at room temperature.
  • the reaction mixture can be heated to facilitate the reduction.
  • the heating range is 30 ° C to 100 ° C, preferably 40 ° C to 90 ° C, more preferably 50 ° C to 80 ° C.
  • known conditions can be used. For example, heat treatment may be performed at 700 ° C. to 1200 ° C. in a vacuum or an inert gas.
  • the high thermal conductive resin composition of the present invention includes the above carbon-modified boron nitride and a resin.
  • the high thermal conductive resin composition can be obtained by mixing carbon-modified boron nitride and a resin.
  • the amount of carbon-modified boron nitride mixed with the resin is typically 1% to 90% by volume, preferably 10% to 90% by volume, more preferably 20% to 90% by volume. If the mixing amount is less than 1% by volume, thermal conductivity may not be obtained.
  • the method of mixing the carbon-modified boron nitride of the present invention with a resin is a dry process in which, when the resin is a solid, the carbon-modified boron nitride and the carbon-modified boron nitride are mixed with powder and then melt mixed using a kneader or a twin screw extruder. Alternatively, it can be carried out by a wet process in which a resin is dissolved in an appropriate solvent and mixed with carbon-modified boron nitride and stirred or dispersed using a homogenizer or bead mill. These methods can be appropriately selected depending on the properties of the resin used.
  • the resin is liquid, mix it with carbon-modified boron nitride using a stirrer, three-roll or kneader, or mix and stir the resin with carbon-modified boron nitride by diluting the resin with an appropriate solvent or diluent.
  • a mixing process can be performed by a dispersion process using a homogenizer or a bead mill. These methods can be appropriately selected depending on the properties of the resin used.
  • the resin examples include polyolefin, polycycloolefin, polystyrene, ABS, polycarbonate, polyamide, polyimide, polyacrylate, polyethylene terephthalate, polyphenylene sulfide, epoxy resin, urethane resin, silicone resin, phenol resin, and the like.
  • the resin composition may further contain a curing agent, a crosslinking agent, a polymerization initiator, a high molecular compound or a low molecular compound for adjusting physical properties, and an inorganic filler such as silica or clay as necessary.
  • the oxidized graphite was diluted with 100 ml of a mixed solution adjusted to have a hydrogen peroxide concentration of 0.5% and a sulfuric acid concentration of 3%, and the oxidized graphite was centrifuged. The precipitate was again dispersed in 100 ml of a mixture containing 0.5% hydrogen peroxide and 3% sulfuric acid, and then centrifuged to obtain graphite oxide.
  • the centrifugal sediment is dispersed in 100 ml of a mixture containing 0.5% hydrogen peroxide and 3% sulfuric acid, placed in a dialysis membrane, soaked in ion-exchanged water, and exchanged ion-exchanged water for 7 days. Dialysis was performed. Next, the dialysate was put into an ultrasonic cleaner and subjected to ultrasonic irradiation for 8 hours, and then the supernatant was taken out by centrifugation to obtain a graphene oxide dispersion having a concentration of 0.044 g / 100 ml.
  • the longest sheet has a length distribution of 100 nm to 2000 nm and a thickness of 1 nm to 18 nm. The object was observed.
  • Example 1 (Production of carbon-modified boron nitride having a graphene oxide layer) Hexagonal boron nitride powder (Showa Denko Shobinu (registered trademark) UHP-2) was added to 50 ml of a 0.044 g / 100 ml graphene oxide dispersion while irradiating ultrasonic waves with an ultrasonic cleaner.
  • Hexagonal boron nitride powder Showa Denko Shobinu (registered trademark) UHP-2
  • boron nitride powder was added, coagulation precipitation occurred, and as the amount added increased, the color of the supernatant (brown) became lighter, and when 7.5 g of boron nitride powder was added, the supernatant became almost colorless.
  • the precipitate was separated by filtration, washed with 100 ml of distilled water and 100 ml of methanol, and dried at 60 ° C. for 8 hours to obtain a light brown powder (referred to as carbon-modified UHP-2).
  • carbon-modified UHP-2 a light brown powder
  • this powder was observed with a field emission scanning electron microscope, many wrinkles were observed on the surface of the flat boron nitride particles as shown in FIG. Since such a soot is not seen in the raw material boron nitride particles, this soot is considered to be due to the graphene oxide formed on the surface of the boron nitride particles.
  • Example 2 Production of carbon-modified boron nitride having a reduced graphene oxide layer
  • hexagonal boron nitride powder While adding hexagonal boron nitride powder to 50 ml of a 0.044 g / 100 ml graphene oxide dispersion, it was added.
  • boron nitride powder was added, coagulation precipitation occurred, and as the amount added increased, the color of the supernatant (brown) became lighter, and when 7.5 g of boron nitride powder was added, the supernatant became almost colorless.
  • 5 ml of hydrazine hydrate was added and stirred overnight at room temperature.
  • the formed precipitate was filtered off, washed with 100 ml of distilled water and 100 ml of methanol, and then dried at 60 ° C. for 8 hours to obtain a gray powder (reduced form).
  • Carbon modified UHP-2 When micro Raman spectra were measured at five different points on the surface of the dried boron nitride particles, the G band of reduced graphene oxide could be observed at all measurement points. Therefore, nitriding covered with reduced graphene oxide was performed. It is considered that boron particles are obtained.
  • Example 3 Preparation of resin composition containing carbon-modified boron nitride 1
  • 33 parts by weight of bis-A type epoxy Mitsubishi Chemical: Ep828)
  • 19 parts by weight of phenol novolak DIC: TD2090
  • 2-ethyl-4-methylimidazole Nacalai Tesque: 2E4MZ
  • 48 parts by weight of carbon-modified UHP-2 prepared in Example 1 was added and kneaded until uniform in a mortar to obtain a boron nitride mixture (the boron nitride addition amount was 35 vol%).
  • the obtained mixture was dried at 120 ° C. for 4 minutes, and pressed with a vacuum press at 140 ° C./0.5 MPa / 5 minutes and 180 ° C./0.5 MPa / 2 hours to obtain a cured product.
  • Example 4 (Preparation of resin composition containing carbon-modified boron nitride 2) A cured epoxy resin was obtained in the same manner as in Example 3 except that the amount of carbon-modified UHP-2 prepared in Example 1 was changed to 45 vol%.
  • Comparative Example 2 A cured epoxy resin was prepared in the same manner as in Comparative Example 1, except that the amount of boron nitride (Showen D (registered trademark) UHP-2 manufactured by Showa Denko) was 45 vol%.
  • boron nitride Showen D (registered trademark) UHP-2 manufactured by Showa Denko
  • Example 3 and Comparative Example 1 and Example 4 and Comparative Example 2 having the same addition amount are compared, the cured product using carbon-modified boron nitride clearly has a thickness direction and a planar direction. Both had improved thermal conductivity. In particular, the thermal conductivity in the thickness direction was greatly improved by 23% in Example 2. The reason why the thermal conductivity is different between the planar direction and the thickness direction in the produced cured product is considered to be because boron nitride is oriented in the planar direction.
  • the cause of the improvement in the thermal conductivity in the thickness direction in particular was considered to be that the affinity between the boron nitride surface and the resin was improved, resulting in a decrease in void formation due to separation at the interface between the two. .
  • Example 5 Preparation of resin composition containing carbon-modified boron nitride 3 20 parts by weight of bis-A type epoxy (Mitsubishi Chemical: Ep828), 11 parts by weight of phenol novolac (DIC: TD2090), and 0.3 parts by weight of 2-ethyl-4-methylimidazole (Nacalai Tesque: 2E4MZ) are used in a mortar.
  • Example 2 38 parts by weight of carbon-modified UHP-2 prepared in Example 1 and 31 parts by weight of spherical alumina CB A20S were added and kneaded until uniform in a mortar to obtain a boron nitride-alumina mixture (nitriding)
  • the boron addition amount is 35 vol%
  • the alumina addition amount is 15 vol%
  • the total filler addition amount is 50 vol%).
  • the obtained mixture was dried at 120 ° C. for 4 minutes, and pressed with a vacuum press at 140 ° C./20 MPa / 5 minutes and 180 ° C./0.5 MPa / 2 hours to obtain a cured product.
  • the thermal diffusivity in the thickness direction and the plane direction was measured using a Bethel thermowave analyzer TA (periodic heating method), and the thermal conductivity in the thickness direction and the plane direction was calculated from the specific heat and specific gravity of the cured product. .
  • Example 6 (Preparation of resin composition containing carbon-modified boron nitride 2-5) Spherical alumina (A cured epoxy resin was prepared in the same manner as in Example 5 except that the amount of CB A20S manufactured by Showa Denko was changed to 25, 35, and 40 vol% according to Table 2, and the thermal conductivity in the thickness direction and the planar direction was produced. was calculated.
  • Example 5 and Comparative Example 3 and Example 6 and Comparative Example 4 having the same addition amount are compared, the cured product using carbon-modified boron nitride clearly has a thickness direction.
  • the thermal conductivity was improved in the plane direction.
  • the heat conductivity in the thickness direction was greatly improved by 61% in Example 8. The reason why the thermal conductivity is different between the planar direction and the thickness direction in the produced cured product is considered to be because boron nitride is oriented in the planar direction.
  • the factors that particularly improved the thermal conductivity in the thickness direction were that the addition of spherical alumina disturbed the planar orientation of boron nitride, increasing the heat path in the thickness direction, and the surface of the boron nitride surface.
  • the affinity between the resin and the resin it is considered that void formation due to separation at the interface between the two has decreased.
  • Example 9 (Preparation of resin composition containing carbon-modified boron nitride 6) Solvent-free silicone resin (KNS-320A manufactured by Shin-Etsu Chemical Co., Ltd.) 1.56 parts by weight and 2.18 parts by weight of carbon-modified boron nitride prepared in Example 1 and a curing agent (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) 0 .03 parts by weight were mixed well in a mortar. The mixture was put into a square container made of polytetrafluoroethylene and subjected to vacuum degassing (room temperature 30 minutes), then the lid was spread with a plate made of polytetrafluoroethylene, covered and heated at 80 ° C.
  • KNS-320A manufactured by Shin-Etsu Chemical Co., Ltd. Solvent-free silicone resin
  • CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.
  • the obtained cured product is taken out from the mold, and the thermal diffusivity in the thickness direction is measured using Bethel Thermowave Analyzer TA (periodic heating method), and the thermal conductivity in the thickness direction is determined from the specific heat and specific gravity of the cured product. When calculated, the thermal conductivity was 1.31 W / (m ⁇ K).
  • Example 7 A cured product was prepared in the same manner as in Example 9 except that the carbon-modified boron nitride was changed to unmodified boron nitride (Showa Denko (registered trademark) UHP-2), and the thermal conductivity in the thickness direction was calculated. As a result, the thermal conductivity was 0.82 W / (m ⁇ K). Compared with Example 9, the heat conductivity was higher when carbon-modified boron nitride was used.
  • the carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the particle surface, thereby improving the affinity with the resin and improving the fluidity of the blended resin composition and the interfacial adhesion between the boron nitride and the resin. can do.
  • the heat conductive resin composition excellent in mechanical strength and heat conductivity can be provided, and can be used as a heat conductive material and a heat dissipation material for various devices.

Abstract

Provided is an energy-conserving carbon-modified boron nitride with good resin affinity having a sheet-like carbon layer on the particle surface. Also provided is a highly heat-conductive resin composition containing the carbon-modified boron nitride and a resin. This carbon-modified boron nitride has a sheet-like carbon layer on the boron nitride particle surface, a preferred sheet-like carbon layer being 1-20 layers of graphene oxide or 1-20 layers of reduced graphene oxide.

Description

カーボン修飾窒化ホウ素、その製造方法および高熱伝導性樹脂組成物Carbon-modified boron nitride, method for producing the same, and high thermal conductive resin composition
　本発明は、窒化ホウ素と樹脂からなる高熱伝導材料に関し、具体的には、表面改質された窒化ホウ素に関する。 The present invention relates to a high thermal conductive material composed of boron nitride and a resin, and specifically to a surface-modified boron nitride.
　電子・通信機器の小型化・高密度化やＬＥＤ照明機器の高性能化に伴い、発生する熱を効率よく放熱する重要性が高まり、熱伝導性の高い樹脂材料の開発が進められている。従来、樹脂材料の熱伝導性を高めるためにグラファイトやアルミナなどの金属酸化物粉末を混合することが行われている。しかしながら、グラファイトを用いると樹脂材料の電気伝導性が高くなる問題がある。金属酸化物では、十分な熱伝導性が得られない問題がある。 With the miniaturization and high density of electronic / communication equipment and the high performance of LED lighting equipment, the importance of efficiently dissipating the generated heat is increasing, and the development of resin materials with high thermal conductivity is being promoted. Conventionally, in order to increase the thermal conductivity of a resin material, mixing of metal oxide powders such as graphite and alumina has been performed. However, when graphite is used, there is a problem that the electrical conductivity of the resin material is increased. A metal oxide has a problem that sufficient thermal conductivity cannot be obtained.
　こうした問題に対して、電気伝導性がなく高熱伝導性を有する窒化ホウ素などの窒化物が期待されている。しかしながら、窒化ホウ素表面には官能基がひじょうに少ないため、樹脂との親和性が低い。そのため、樹脂への分散性が悪いことや窒化ホウ素表面と樹脂との界面で剥離が起こって空隙ができやすい問題がある。 In response to these problems, nitrides such as boron nitride having no electrical conductivity and high thermal conductivity are expected. However, since the boron nitride surface has very few functional groups, the affinity with the resin is low. For this reason, there are problems that the dispersibility in the resin is poor, and that separation occurs at the interface between the boron nitride surface and the resin and voids are easily formed.
　窒化ホウ素と樹脂との親和性を改善するため、窒化ホウ素にあるアミノ基や水酸基にシランカップリング剤や有機化合物などを反応させることが行われている。しかし、これらの基は主にグラファイトと同様の層状構造を持つ窒化ホウ素の結晶シートの端面に存在しているため、窒化ホウ素表面の樹脂親和性改善にはあまり効果がない。 In order to improve the affinity between boron nitride and resin, a silane coupling agent, an organic compound, or the like is reacted with an amino group or a hydroxyl group in boron nitride. However, since these groups are mainly present on the end face of the boron nitride crystal sheet having a layered structure similar to that of graphite, it is not very effective in improving the resin affinity on the boron nitride surface.
　窒化ホウ素全面の改質方法としては、例えば、大気中での加熱酸化（特許文献１）、超臨界水又は亜臨界水を用いた表面酸化（特許文献２）、プラズマ処理によるアミノ基導入（特許文献３）、メカノケミカル処理（特許文献４）などが提案されている。 Examples of methods for reforming the entire surface of boron nitride include heating oxidation in air (Patent Document 1), surface oxidation using supercritical water or subcritical water (Patent Document 2), and introduction of amino groups by plasma treatment (Patent Document 1). Document 3), mechanochemical treatment (Patent Document 4) and the like have been proposed.
特開平９－１２７７１号公報Japanese Patent Laid-Open No. 9-12771 特許５７２２０１６号Patent 572216 特開２０１５－１３７３３５号公報JP2015-137335A 特開２０１５－３６３６１号公報Japanese Patent Laying-Open No. 2015-36361
　本発明は前記課題を解決するためになされたものであり、その目的とするところは、省エネルギー、低コストで樹脂親和性の良い窒化ホウ素を提供することにある。 The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide boron nitride having good resin compatibility with energy saving, low cost.
　さらには、前記カーボン修飾窒化ホウ素を樹脂に混合して高熱伝導性樹脂組成物を提供することにある。 Furthermore, another object is to provide a high thermal conductive resin composition by mixing the carbon-modified boron nitride with a resin.
　本発明のカーボン修飾窒化ホウ素は、窒化ホウ素粒子表面にシート状カーボン層を有する。 The carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the surface of boron nitride particles.
　好ましい実施態様においては、前記シート状カーボン層が１層～２０層の酸化グラフェンであり、または、前記シート状カーボン層が１層～２０層の還元型酸化グラフェンである。 In a preferred embodiment, the sheet-like carbon layer is 1 to 20 layers of graphene oxide, or the sheet-like carbon layer is 1 to 20 layers of reduced graphene oxide.
　本発明の高熱伝導性樹脂組成物は、上記のカーボン修飾窒化ホウ素と樹脂とを含む。 The high thermal conductive resin composition of the present invention includes the above carbon-modified boron nitride and a resin.
　本発明のカーボン修飾窒化ホウ素粒子の製造方法は、酸化グラフェン水分散液と窒化ホウ素粉末とを混合する工程、および、前記混合で得られた液から固体を回収して乾燥し、カーボン修飾窒化ホウ素を得る工程、を含む。 The method for producing carbon-modified boron nitride particles of the present invention includes a step of mixing an aqueous graphene oxide dispersion and boron nitride powder, and collecting and drying a solid from the liquid obtained by the mixing, and carbon-modified boron nitride. Obtaining.
　１つの実施態様においては、上記方法は、上記カーボン修飾窒化ホウ素を還元剤で還元する工程をさらに含む。 In one embodiment, the method further includes the step of reducing the carbon-modified boron nitride with a reducing agent.
　本発明によれば、粒子表面にシート状カーボン層を有する窒化ホウ素を省エネルギー、低コストで提供できる。それにより、窒化ホウ素と樹脂との親和性が向上するため、配合された樹脂組成物の流動性や窒化ホウ素と樹脂との界面接着性を向上することができる。それにより電気伝導性がなく機械的強度と熱伝導性の優れた熱伝導性樹脂組成物を提供できる。 According to the present invention, boron nitride having a sheet-like carbon layer on the particle surface can be provided with energy saving and low cost. Thereby, since the affinity between boron nitride and the resin is improved, the fluidity of the blended resin composition and the interfacial adhesion between the boron nitride and the resin can be improved. Thereby, there can be provided a heat conductive resin composition having no electrical conductivity and excellent mechanical strength and thermal conductivity.
表面にシート状カーボン層を有する窒化ホウ素粒子の走査型電子顕微鏡写真。The scanning electron micrograph of the boron nitride particle which has a sheet-like carbon layer on the surface.
　以下、本発明の好ましい実施形態について説明するが、本発明はこれらの実施形態には限定されない。 Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.
　本発明のカーボン修飾窒化ホウ素は、窒化ホウ素粒子表面にシート状カーボン層を有しており、このシート状カーボン層は樹脂と窒化ホウ素界面の親和性を改善する機能を有する。シート状カーボン層は、酸化グラフェン、または、この酸化グラフェンを化学的還元および／または加熱による物理的還元処理した還元型酸化グラフェンである。還元方法は、公知の技術の何れも用いることができ、特に制限はない。 The carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the surface of the boron nitride particles, and this sheet-like carbon layer has a function of improving the affinity between the resin and the boron nitride interface. The sheet-like carbon layer is graphene oxide or reduced graphene oxide obtained by subjecting this graphene oxide to chemical reduction and / or physical reduction treatment by heating. Any known technique can be used for the reduction method, and there is no particular limitation.
　シート状カーボン層を酸化グラフェンとするか、これを還元した還元型酸化グラフェンにするかは、カーボン修飾窒化ホウ素を混合する樹脂の性質によって選択できる。例えば、酸化グラフェンとした場合、酸化グラフェンに水酸基、カルボキシル基、エポキシ基などがあるので、これらを利用して混合する樹脂への親和性を向上することができる。利用方法としては、これらの基を樹脂と化学結合させる方法、これらの基と樹脂分子中の官能基との物理的相互作用を利用する方法、これらの基に樹脂と親和性の良い有機化合物またはオリゴマーを化学結合させる方法などを挙げることができる。なお、化学結合させる場合、当業者であれば容易に実施し得る化学反応ならびに有機化合物およびオリゴマーは全て利用できる。還元型酸化グラフェンとした場合は、ポリフェニレンエーテルなどのような芳香族基を多く有する樹脂への親和性向上が期待できる。 Whether the sheet-like carbon layer is graphene oxide or reduced graphene oxide obtained by reducing the sheet carbon layer can be selected depending on the properties of the resin mixed with the carbon-modified boron nitride. For example, when graphene oxide is used, since graphene oxide includes a hydroxyl group, a carboxyl group, an epoxy group, and the like, the affinity for a resin to be mixed can be improved using these. As a method of use, a method of chemically bonding these groups to a resin, a method of using physical interaction between these groups and a functional group in the resin molecule, an organic compound having good affinity with the resin for these groups, or Examples include a method of chemically bonding oligomers. In the case of chemical bonding, all chemical reactions and organic compounds and oligomers that can be easily carried out by those skilled in the art can be used. In the case of reduced graphene oxide, an improvement in affinity for a resin having many aromatic groups such as polyphenylene ether can be expected.
　グラファイトをハマーズ法などにより酸化・剥離して得られる酸化グラフェンは、単層の酸化グラフェン、単層の酸化グラフェンが複数積層した複層酸化グラフェンおよび内部に酸化されていない層が存在する複層酸化グラフェンの混合物となる。本明細書では、これら全て含めて酸化グラフェンとする。こうした混合物をそのまま使うとシート状カーボン層は単層から複層の酸化グラフェンが混ざった層になる。なお、酸化グラフェン同士の電気的反発により、窒化ホウ素粒子上の酸化グラフェンにさらに別の酸化グラフェンは積層しないため、シート状カーボン層の酸化グラフェン層数の分布は、最初の酸化グラフェンの層数の分布が反映される。窒化ホウ素粒子上の酸化グラフェンを還元した場合、還元型酸化グラフェンの層数は、元の酸化グラフェンの層数が維持されると考えられる。 Graphene oxide obtained by oxidizing and exfoliating graphite using the Hammers method is a single layer graphene oxide, multi-layer graphene oxide composed of multiple layers of single-layer graphene oxide, and multi-layer oxidation with a non-oxidized layer inside It becomes a mixture of graphene. In this specification, all of these are referred to as graphene oxide. If such a mixture is used as it is, the sheet-like carbon layer becomes a layer in which single-layer to multi-layer graphene oxide is mixed. In addition, since another graphene oxide is not stacked on the graphene oxide on the boron nitride particles due to electrical repulsion between the graphene oxides, the distribution of the number of graphene oxide layers in the sheet-like carbon layer is the number of graphene oxide layers Distribution is reflected. When graphene oxide on the boron nitride particles is reduced, the number of layers of reduced graphene oxide is considered to maintain the original number of graphene oxide layers.
　シート状カーボン層の前記機能は、１層～２０層、好ましくは１層～１０層、より好ましくは１層～７層の酸化グラフェンまたは還元型酸化グラフェンにより発揮される。２０層より多くなるとグラファイトの性質が支配的となり、本発明の効果が発揮されない場合がある。ここで、酸化グラフェンおよび還元型酸化グラフェンの層数は、例えば、原子間力顕微鏡、透過型電子顕微鏡、ラマンスペクトルなどで評価することができる。 The function of the sheet-like carbon layer is exhibited by 1 to 20 layers, preferably 1 to 10 layers, more preferably 1 to 7 layers of graphene oxide or reduced graphene oxide. If it exceeds 20 layers, the properties of graphite become dominant and the effects of the present invention may not be exhibited. Here, the number of layers of graphene oxide and reduced graphene oxide can be evaluated by, for example, an atomic force microscope, a transmission electron microscope, a Raman spectrum, or the like.
　シート状カーボン層は窒化ホウ素粒子全面を覆っている必要はないが、樹脂親和性向上効果の面からみると、被覆割合（＝炭素原子数／ホウ素原子数比）は、少なくとも０．２以上、好ましくは０．３以上、より好ましくは０．５以上である。この被覆割合は、Ｘ線光電子分光法から推定できる。また、複数ポイントの顕微ラマンスペクトル測定を行い、酸化グラフェンに由来するＤまたはＧバンドが観測されるポイント数の全測定ポイント数に対する割合を用いて被覆割合とすることもできる。この場合も被覆割合は、少なくとも０．２以上、好ましくは０．３以上、より好ましくは０．５以上である。なお、シート状カーボン層は、代表的には窒化ホウ素粒子に吸着することにより積層されている。 The sheet-like carbon layer does not need to cover the entire surface of the boron nitride particles, but from the viewpoint of the resin affinity improvement effect, the covering ratio (= carbon atom / boron atom ratio) is at least 0.2 or more, Preferably it is 0.3 or more, More preferably, it is 0.5 or more. This coverage ratio can be estimated from X-ray photoelectron spectroscopy. Further, a micro Raman spectrum measurement of a plurality of points is performed, and the coverage ratio can be obtained by using a ratio of the number of points at which D or G bands derived from graphene oxide are observed to the total number of measurement points. Also in this case, the covering ratio is at least 0.2 or more, preferably 0.3 or more, more preferably 0.5 or more. The sheet-like carbon layer is typically laminated by being adsorbed on boron nitride particles.
　窒化ホウ素には六方晶、立方晶等様々な結晶構造のものが知られており、本発明では、いずれをも用いることができる。これらの窒化ホウ素の中で、工業的に入手しやすく、安価であることから六方晶窒化ホウ素粉末が好ましい。窒化ホウ素のサイズは、一般的に熱伝導分野の使用に適する大きさであれば特に限定されない。平均粒径は、好ましくは０．１μｍ～１００μｍ、より好ましくは０．５μｍ～６０μｍである。平均粒径が０．１μｍより小さいと、ナノ粒子効果が強くなって得られる樹脂組成物の流動性が低下する場合がある。平均粒径が１００μｍより大きいと、得られる樹脂組成物から例えば熱伝導層を形成する場合の層厚を十分に薄くできなくなる場合がある。窒化ホウ素の平均粒径は、例えば、レーザー回折・散乱法で測定した平均粒径（ｄ５０）が採用され得る。 Boron nitride has various crystal structures such as hexagonal crystal and cubic crystal, and any of them can be used in the present invention. Among these boron nitrides, hexagonal boron nitride powder is preferable because it is easily available industrially and is inexpensive. The size of boron nitride is not particularly limited as long as it is generally suitable for use in the heat conduction field. The average particle diameter is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 60 μm. When the average particle size is smaller than 0.1 μm, the fluidity of the resin composition obtained by strengthening the nanoparticle effect may be lowered. If the average particle size is larger than 100 μm, the layer thickness in the case of forming a heat conductive layer from the obtained resin composition may not be sufficiently reduced. As the average particle diameter of boron nitride, for example, an average particle diameter (d50) measured by a laser diffraction / scattering method can be adopted.
　酸化グラフェンは、グラファイトをＨｕｍｍｅｒｓ法として知られる公知の方法を用いて酸化し、１層～２０層に剥離処理して得た０．０１ｗ％～５ｗ％水性分散液を利用できる。媒体としては、水を主体として酸化グラフェンが凝集しない範囲で、親水性溶媒、例えば、メタノール、エタノール等のアルコール類、エチレングリコールなどのグリコール類、テトラヒドロフランなどを加えることができる。得られる酸化グラフェンは、様々な形状のものがあるが、一般的な形状は周囲に凹凸のある矩形に近い形状を持つ薄いシート状であり、その大きさは原料のグラファイト結晶の大きさに依存する。しかし、実際にはシートの大きさは広い分布を持っているため、利用においては大きさに特に制限はないが、目安としては存在するシートの最も長いところの長さが窒化ホウ素粒子の平均粒子径の１／１０００～２／１、好ましくは１／５００～１／１、より好ましくは１／１０～０．７／１である。１／１０００～２／１の範囲外であるとシート状カーボン層となりにくい。 As graphene oxide, 0.01 w% to 5 w% aqueous dispersion obtained by oxidizing graphite using a known method known as the Hummers method and performing exfoliation treatment to 1 to 20 layers can be used. As the medium, hydrophilic solvents such as alcohols such as methanol and ethanol, glycols such as ethylene glycol, tetrahydrofuran and the like can be added as long as graphene oxide is mainly agglomerated and does not aggregate. The graphene oxide obtained has various shapes, but the general shape is a thin sheet with a shape close to a rectangle with irregularities around it, the size of which depends on the size of the raw graphite crystals To do. However, since the sheet size actually has a wide distribution, there is no particular limitation on the size in use, but as a guide, the longest length of the existing sheet is the average particle size of boron nitride particles The diameter is 1/1000 to 2/1, preferably 1/500 to 1/1, and more preferably 1/10 to 0.7 / 1. When it is out of the range of 1/1000 to 2/1, it is difficult to form a sheet-like carbon layer.
　カーボン修飾窒化ホウ素は、酸化グラフェン水性分散液に窒化ホウ素粉末を加えて、撹拌または必要に応じてホモジナイザー等の強力な分散装置を用いて分散し、次いで分散液から濾別または遠心沈降によって回収した後、室温乾燥または必要に応じて加熱乾燥することにより粉体として得ることができる。酸化グラフェン水性分散液に窒化ホウ素粉末を分散していくと、沈殿が生じて上澄み（酸化グラフェン水性分散液層）の色が薄くなっていく。最終的に上澄みは無色透明となり、上澄みから酸化グラフェンは検出されなくなる。すなわち、酸化グラフェン水性分散液に窒化ホウ素粉末を分散するだけで、窒化ホウ素粒子への酸化グラフェンの吸着が起こっているものと考えられる。よって、酸化グラフェン水性分散液への窒化ホウ素の添加量は、窒化ホウ素粒子表面にどれだけ吸着させるかによって任意に選択することができる。 Carbon-modified boron nitride is dispersed in graphene oxide aqueous dispersion by adding boron nitride powder and stirring or using a powerful dispersing device such as a homogenizer as necessary, and then recovered from the dispersion by filtration or centrifugal sedimentation. Then, it can obtain as a powder by drying at room temperature or heat-drying as needed. When boron nitride powder is dispersed in an aqueous graphene oxide dispersion, precipitation occurs and the color of the supernatant (graphene oxide aqueous dispersion layer) becomes lighter. Finally, the supernatant becomes colorless and transparent, and graphene oxide is not detected from the supernatant. That is, it is considered that the adsorption of graphene oxide to the boron nitride particles occurs only by dispersing the boron nitride powder in the graphene oxide aqueous dispersion. Accordingly, the amount of boron nitride added to the graphene oxide aqueous dispersion can be arbitrarily selected depending on how much boron nitride is adsorbed on the surface of the boron nitride particles.
　前記分散液または乾燥物を還元剤で還元する化学還元、または乾燥物を加熱処理する加熱還元によりシート状カーボン層を還元型酸化グラフェンとすることができる。化学還元の還元剤としては、公知のものを用いることができ、例えば、ヒドラジンや、塩酸ヒドラジン、硫酸ヒドラジン、抱水ヒドラジン等のヒドラジン化合物等のヒドラジン系還元剤、水素化ホウ素ナトリウム、亜硫酸ナトリウム、亜硫酸水素ナトリウム、チオ硫酸ナトリウム、亜硝酸ナトリウム、次亜硝酸ナトリウム、亜リン酸及び亜リン酸ナトリウム等のその塩、次亜リン酸及び次亜リン酸ナトリウム等のその塩、ヨウ化水素、アスコルビン酸、エタノールなどのアルコール類、エチレングリコールなどのグリコール類等を挙げることができ、これらを１種または２種以上用いることができる。使用量は、酸化グラフェンの重量の０．１倍～５０倍、好ましくは０．５倍～３０倍、より好ましくは１倍～２０倍を用いることが好ましい。還元剤の総量が前記範囲より少ないと反応が進み難い場合があり、前記範囲より多いと系から除く手間がかかる場合がある。還元時間は、室温で還元を行う場合、１時間～７２時間である。還元を促進するために反応混合物を加熱することができる。加熱範囲としては、３０℃～１００℃、好ましくは４０℃～９０℃、より好ましくは５０℃～８０℃である。加熱還元としては、公知の条件を利用できるが、例えば、真空または不活性気体中、７００℃～１２００℃で熱処理すればよい。 The sheet-like carbon layer can be converted into reduced graphene oxide by chemical reduction in which the dispersion or the dried product is reduced with a reducing agent, or heat reduction in which the dried product is heat-treated. As the reducing agent for chemical reduction, known ones can be used. For example, hydrazine, hydrazine reducing agents such as hydrazine compounds such as hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate, sodium borohydride, sodium sulfite, Sodium bisulfite, sodium thiosulfate, sodium nitrite, sodium hyponitrite, phosphorous acid and its salts such as sodium phosphite, hypophosphorous acid and its salts such as sodium hypophosphite, hydrogen iodide, ascorbine Examples thereof include acids, alcohols such as ethanol, glycols such as ethylene glycol, and the like, and one or more of these can be used. The amount used is preferably 0.1 to 50 times, preferably 0.5 to 30 times, more preferably 1 to 20 times the weight of graphene oxide. If the total amount of the reducing agent is less than the above range, the reaction may not proceed easily, and if it exceeds the above range, it may take time to remove from the system. The reduction time is 1 hour to 72 hours when the reduction is performed at room temperature. The reaction mixture can be heated to facilitate the reduction. The heating range is 30 ° C to 100 ° C, preferably 40 ° C to 90 ° C, more preferably 50 ° C to 80 ° C. As the heat reduction, known conditions can be used. For example, heat treatment may be performed at 700 ° C. to 1200 ° C. in a vacuum or an inert gas.
　本発明の高熱伝導性樹脂組成物は、上記のカーボン修飾窒化ホウ素と樹脂とを含む。高熱伝導性樹脂組成物は、カーボン修飾窒化ホウ素と樹脂とを混合することによって得ることができる。樹脂に対するカーボン修飾窒化ホウ素の混合量は、代表的には１体積％～９０体積％、好ましくは１０体積％～９０体積％、より好ましくは２０体積％～９０体積％である。混合量が１体積％より少ないと熱伝導性が得られない場合がある。窒化ホウ素の配合量は多い方が熱伝導性が高くなるので上限は特に限定されないが、樹脂組成物の機械的強度を考慮すると上限は９０体積％程度が好ましい。 The high thermal conductive resin composition of the present invention includes the above carbon-modified boron nitride and a resin. The high thermal conductive resin composition can be obtained by mixing carbon-modified boron nitride and a resin. The amount of carbon-modified boron nitride mixed with the resin is typically 1% to 90% by volume, preferably 10% to 90% by volume, more preferably 20% to 90% by volume. If the mixing amount is less than 1% by volume, thermal conductivity may not be obtained. The higher the boron nitride content, the higher the thermal conductivity, so the upper limit is not particularly limited, but the upper limit is preferably about 90% by volume considering the mechanical strength of the resin composition.
　本発明のカーボン修飾窒化ホウ素を樹脂と混合する方法は、樹脂が固体の場合は、これらとカーボン修飾窒化ホウ素を紛体で混合した後、ニーダーや二軸押出機などを用いて溶融混合する乾式プロセス、あるいは、樹脂を適切な溶剤に溶解してカーボン修飾窒化ホウ素と混合・撹拌またはホモジナイザーやビーズミルを用いた分散処理をする湿式プロセスで行うことができる。これらの方法は、用いる樹脂の性状によって適宜選択することができる。樹脂が液状の場合は、これらとカーボン修飾窒化ホウ素とを攪拌機、３本ロールやニーダーなどを用いて混合、あるいは、樹脂を適切な溶剤または希釈剤で希釈してカーボン修飾窒化ホウ素と混合・撹拌またはホモジナイザーやビーズミルを用いた分散処理をすることで混合処理できる。これらの方法は、用いる樹脂の性状によって適宜選択することができる。 The method of mixing the carbon-modified boron nitride of the present invention with a resin is a dry process in which, when the resin is a solid, the carbon-modified boron nitride and the carbon-modified boron nitride are mixed with powder and then melt mixed using a kneader or a twin screw extruder. Alternatively, it can be carried out by a wet process in which a resin is dissolved in an appropriate solvent and mixed with carbon-modified boron nitride and stirred or dispersed using a homogenizer or bead mill. These methods can be appropriately selected depending on the properties of the resin used. If the resin is liquid, mix it with carbon-modified boron nitride using a stirrer, three-roll or kneader, or mix and stir the resin with carbon-modified boron nitride by diluting the resin with an appropriate solvent or diluent. Alternatively, a mixing process can be performed by a dispersion process using a homogenizer or a bead mill. These methods can be appropriately selected depending on the properties of the resin used.
　上記樹脂としては、ポリオレフィン、ポリシクロオレフィン、ポリスチレン、ＡＢＳ、ポリカーボネート、ポリアミド、ポリイミド、ポリアクリレート、ポリエチレンテレフタレート、ポリフェニレンスルフィド、エポキシ樹脂、ウレタン樹脂、シリコーン樹脂、フェノール樹脂などを挙げることができる。 Examples of the resin include polyolefin, polycycloolefin, polystyrene, ABS, polycarbonate, polyamide, polyimide, polyacrylate, polyethylene terephthalate, polyphenylene sulfide, epoxy resin, urethane resin, silicone resin, phenol resin, and the like.
　前記樹脂組成物は、必要に応じてさらに硬化剤、架橋剤、重合開始剤、物性を調整するための高分子化合物または低分子化合物、シリカやクレイのような無機フィラーを含むことができる。 The resin composition may further contain a curing agent, a crosslinking agent, a polymerization initiator, a high molecular compound or a low molecular compound for adjusting physical properties, and an inorganic filler such as silica or clay as necessary.
　以下、実施例により本発明を具体的に説明するが、本発明はこれら実施例には限定されない。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.
（酸化グラフェン分散液の作製）
　硝酸ナトリウム０．３ｇおよび過マンガン酸カリウム１．８ｇを濃硫酸１４ｍｌに溶解させ、これに日本黒鉛製グラファイトＡＣＢ１５０　０．２ｇを加えて室温で攪拌した。７日間攪拌後、反応液を冷却して５％硫酸水５０ｍｌをゆっくりと加え、さらに３０％過酸化水素水１０ｍｌを加えて１時間室温で攪拌した。次いで、過酸化水素濃度０．５％および硫酸濃度３％となるように調整した混合液１００ｍｌで希釈して、酸化したグラファイトを遠心沈降させた。沈殿物を再び０．５％の過酸化水素と３％の硫酸を含む混合液１００ｍｌに分散させ、次いで遠心沈降させることにより、酸化グラファイトを得た。 (Preparation of graphene oxide dispersion)
0.3 g of sodium nitrate and 1.8 g of potassium permanganate were dissolved in 14 ml of concentrated sulfuric acid, 0.2 g of graphite ACB150 made from Nippon Graphite was added thereto, and the mixture was stirred at room temperature. After stirring for 7 days, the reaction solution was cooled, 50 ml of 5% sulfuric acid aqueous solution was slowly added, and further 10 ml of 30% hydrogen peroxide solution was added and stirred at room temperature for 1 hour. Next, the oxidized graphite was diluted with 100 ml of a mixed solution adjusted to have a hydrogen peroxide concentration of 0.5% and a sulfuric acid concentration of 3%, and the oxidized graphite was centrifuged. The precipitate was again dispersed in 100 ml of a mixture containing 0.5% hydrogen peroxide and 3% sulfuric acid, and then centrifuged to obtain graphite oxide.
　次いで、遠心沈降物を０．５％の過酸化水素と３％の硫酸を含む混合液１００ｍｌに分散させ、これを透析膜に入れてイオン交換水に漬け、イオン交換水を交換しながら７日間透析を行った。次いで、透析液を超音波洗浄機に入れて８時間超音波照射処理した後、遠心分離することにより上澄みを取りだし、濃度０．０４４ｇ／１００ｍｌの酸化グラフェン分散液を得た。分散液を５０倍に希釈してシリコン基板に塗布し、原子間力顕微鏡（ＡＦＭ）で観察したところ、シートの最も長いところの長さが１００ｎｍ～２０００ｎｍ、厚さ１ｎｍ～１８ｎｍの分布を持つシート状物体を観察することができた。 Next, the centrifugal sediment is dispersed in 100 ml of a mixture containing 0.5% hydrogen peroxide and 3% sulfuric acid, placed in a dialysis membrane, soaked in ion-exchanged water, and exchanged ion-exchanged water for 7 days. Dialysis was performed. Next, the dialysate was put into an ultrasonic cleaner and subjected to ultrasonic irradiation for 8 hours, and then the supernatant was taken out by centrifugation to obtain a graphene oxide dispersion having a concentration of 0.044 g / 100 ml. When the dispersion is diluted 50 times and applied to a silicon substrate and observed with an atomic force microscope (AFM), the longest sheet has a length distribution of 100 nm to 2000 nm and a thickness of 1 nm to 18 nm. The object was observed.
（実施例１）
（酸化グラフェン層を有するカーボン修飾窒化ホウ素の作製）
　０．０４４ｇ／１００ｍｌの酸化グラフェン分散液５０ｍｌに六方晶窒化ホウ素粉末（昭和電工　ショウビーエヌ（登録商標）　ＵＨＰ－２）を超音波洗浄器で超音波を照射しながら、加えていった。窒化ホウ素粉末を加えると凝集沈殿が生じ、加える量が増えると上澄みの色（褐色）が薄くなって行き、窒化ホウ素粉末を７．５ｇ加えた時点で上澄みはほぼ無色となった。
　沈殿を濾別して蒸留水１００ｍｌ、メタノール１００ｍｌで洗浄後、６０℃で８時間乾燥して薄茶色の粉末を得た（カーボン修飾ＵＨＰ－２とする）。この粉末を電界放射形走査電子顕微鏡で観察したところ、図１に示すように平板な窒化ホウ素粒子表面に多数の皺が観察された。原料の窒化ホウ素粒子にはこのような皺はみられないことから、この皺は窒化ホウ素粒子表面に形成された酸化グラフェンによるものと考えられる。さらに窒化ホウ素粒子表面の異なる５点の顕微ラマンスペクトルを測定したところ、全ての測定点で酸化グラフェンのＧバンドを観測することができたことから、酸化グラフェンは窒化ホウ素粒子の全面を覆っているものと考えられる。 Example 1
(Production of carbon-modified boron nitride having a graphene oxide layer)
Hexagonal boron nitride powder (Showa Denko Shobinu (registered trademark) UHP-2) was added to 50 ml of a 0.044 g / 100 ml graphene oxide dispersion while irradiating ultrasonic waves with an ultrasonic cleaner. When boron nitride powder was added, coagulation precipitation occurred, and as the amount added increased, the color of the supernatant (brown) became lighter, and when 7.5 g of boron nitride powder was added, the supernatant became almost colorless.
The precipitate was separated by filtration, washed with 100 ml of distilled water and 100 ml of methanol, and dried at 60 ° C. for 8 hours to obtain a light brown powder (referred to as carbon-modified UHP-2). When this powder was observed with a field emission scanning electron microscope, many wrinkles were observed on the surface of the flat boron nitride particles as shown in FIG. Since such a soot is not seen in the raw material boron nitride particles, this soot is considered to be due to the graphene oxide formed on the surface of the boron nitride particles. Further, when microscopic Raman spectra were measured at five different points on the boron nitride particle surface, the graphene oxide covered the entire surface of the boron nitride particles because the G band of graphene oxide was observed at all measurement points. It is considered a thing.
（実施例２）
（還元型酸化グラフェン層を有するカーボン修飾窒化ホウ素の作製）
　０．０４４ｇ／１００ｍｌの酸化グラフェン分散液５０ｍｌに六方晶窒化ホウ素粉末しながら、加えていった。窒化ホウ素粉末を加えると凝集沈殿が生じ、加える量が増えると上澄みの色（褐色）が薄くなって行き、窒化ホウ素粉末を７．５ｇ加えた時点で上澄みはほぼ無色となった。
　次いで、ヒドラジン水和物５ｍｌを加えて１晩室温で撹拌し、生成した沈殿を濾別して蒸留水１００ｍｌ、メタノール１００ｍｌで洗浄後、６０℃で８時間乾燥して灰色の粉末を得た（還元型カーボン修飾ＵＨＰ－２とする）。乾燥した窒化ホウ素粒子表面の異なる５点の顕微ラマンスペクトルを測定したところ、全ての測定点で還元型酸化グラフェンのＧバンドを観測することができたことから、還元型酸化グラフェンに覆われた窒化ホウ素粒子が得られているものと考えられる。 (Example 2)
(Production of carbon-modified boron nitride having a reduced graphene oxide layer)
While adding hexagonal boron nitride powder to 50 ml of a 0.044 g / 100 ml graphene oxide dispersion, it was added. When boron nitride powder was added, coagulation precipitation occurred, and as the amount added increased, the color of the supernatant (brown) became lighter, and when 7.5 g of boron nitride powder was added, the supernatant became almost colorless.
Next, 5 ml of hydrazine hydrate was added and stirred overnight at room temperature. The formed precipitate was filtered off, washed with 100 ml of distilled water and 100 ml of methanol, and then dried at 60 ° C. for 8 hours to obtain a gray powder (reduced form). Carbon modified UHP-2). When micro Raman spectra were measured at five different points on the surface of the dried boron nitride particles, the G band of reduced graphene oxide could be observed at all measurement points. Therefore, nitriding covered with reduced graphene oxide was performed. It is considered that boron particles are obtained.
（実施例３）
（カーボン修飾窒化ホウ素を含む樹脂組成物の作製１）
　ビスＡ型エポキシ（三菱化学製：Ｅｐ８２８）　３３重量部とフェノールノボラック（ＤＩＣ製：ＴＤ２０９０）１９重量部、２－エチル－４－メチルイミダゾール（ナカライテスク製：２Ｅ４ＭＺ）０．５重量部を乳鉢でよく混ぜ合わせ、さらに実施例１で作製したカーボン修飾ＵＨＰ－２　４８重量部を添加して乳鉢で均一になるまで混練して窒化ホウ素混合物を得た（窒化ホウ素添加量は３５ｖｏｌ％）。得られた混合物を１２０℃で４分間乾燥し、真空プレス機にて１４０℃／０．５ＭＰａ／５分、１８０℃／０．５ＭＰａ／２時間プレスを行い、硬化物を得た。 (Example 3)
(Preparation of resin composition containing carbon-modified boron nitride 1)
33 parts by weight of bis-A type epoxy (Mitsubishi Chemical: Ep828), 19 parts by weight of phenol novolak (DIC: TD2090) and 0.5 parts by weight of 2-ethyl-4-methylimidazole (Nacalai Tesque: 2E4MZ) in a mortar Then, 48 parts by weight of carbon-modified UHP-2 prepared in Example 1 was added and kneaded until uniform in a mortar to obtain a boron nitride mixture (the boron nitride addition amount was 35 vol%). The obtained mixture was dried at 120 ° C. for 4 minutes, and pressed with a vacuum press at 140 ° C./0.5 MPa / 5 minutes and 180 ° C./0.5 MPa / 2 hours to obtain a cured product.
（実施例４）
（カーボン修飾窒化ホウ素を含む樹脂組成物の作製２）
　実施例１で作製したカーボン修飾ＵＨＰ－２の添加量を４５ｖｏｌ％にする以外は、実施例３と同様にしてエポキシ樹脂硬化物を得た。 Example 4
(Preparation of resin composition containing carbon-modified boron nitride 2)
A cured epoxy resin was obtained in the same manner as in Example 3 except that the amount of carbon-modified UHP-2 prepared in Example 1 was changed to 45 vol%.
（比較例１）
　窒化ホウ素を未修飾の六方晶窒化ホウ素（昭和電工製ショウビーエヌ（登録商標）　ＵＨＰ－２）にする以外は実施例３と同様にして窒化ホウ素添加量３５ｖｏｌ％のエポキシ樹脂硬化物を作製した。 (Comparative Example 1)
An epoxy resin cured product having a boron nitride addition amount of 35 vol% was prepared in the same manner as in Example 3 except that the boron nitride was changed to unmodified hexagonal boron nitride (Showa Denko (registered trademark) UHP-2). .
（比較例２）
　窒化ホウ素（昭和電工製ショウビーエヌ（登録商標）　ＵＨＰ－２）の添加量を４５ｖｏｌ％にする以外は、比較例１と同様にしてエポキシ樹脂硬化物を作製した。 (Comparative Example 2)
A cured epoxy resin was prepared in the same manner as in Comparative Example 1, except that the amount of boron nitride (Showen D (registered trademark) UHP-2 manufactured by Showa Denko) was 45 vol%.
（熱伝導率の測定）
　べテル製サーモウェーブアナライザ　ＴＡ（周期加熱方式）を用いて、得られた硬化物の厚み方向と平面方向の熱伝導率を算出した。測定結果の一覧を表１に示す。 (Measurement of thermal conductivity)
The thermal conductivity in the thickness direction and the planar direction of the obtained cured product was calculated using a Bethel thermowave analyzer TA (periodic heating method). A list of measurement results is shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、同一添加量である実施例３と比較例１、ならびに実施例４と比較例２を比較すると、カーボン修飾窒化ホウ素を用いた硬化物では、明らかに厚み方向、平面方向ともに熱伝導率が向上していた。特に厚み方向の熱伝導率は、実施例２で２３％の大きな向上がみられた。作製した硬化物において平面方向と厚み方向で熱伝導率が異なるのは、窒化ホウ素が平面方向に配向しているためと考えられる。実施例において、特に厚み方向の熱伝導率の向上がみられた要因としては、窒化ホウ素表面と樹脂との親和性が改善された結果、両者界面の剥離による空隙生成が減ったことが考えられる。 As shown in Table 1, when Example 3 and Comparative Example 1 and Example 4 and Comparative Example 2 having the same addition amount are compared, the cured product using carbon-modified boron nitride clearly has a thickness direction and a planar direction. Both had improved thermal conductivity. In particular, the thermal conductivity in the thickness direction was greatly improved by 23% in Example 2. The reason why the thermal conductivity is different between the planar direction and the thickness direction in the produced cured product is considered to be because boron nitride is oriented in the planar direction. In the examples, the cause of the improvement in the thermal conductivity in the thickness direction in particular was considered to be that the affinity between the boron nitride surface and the resin was improved, resulting in a decrease in void formation due to separation at the interface between the two. .
（顕微ラマンスペクトル測定による酸化グラフェン層を有するカーボン修飾窒化ホウ素の分析）
　実施例１で作製したカーボン修飾窒化ホウ素粒子から無作為に１０個の粒子を選択して顕微ラマンスペクトルを測定（測定装置：Ｈｏｒｉｂａ　ＸｐｌｏＲＡ）し、酸化グラフェン由来の１５９０ｃｍ－１のバンドと窒化ホウ素由来の１３６０ｃｍ－１のバンドのマッピングを行った。すべての粒子について、観察した粒子表面の大部分で１５９０ｃｍ－１のバンドが検出されたことより、窒化ホウ素粒子はまんべんなく表面に酸化グラフェン層を有していると考えられる。また、１５９０ｃｍ－１のバンド強度が強いところは１３６０ｃｍ－１のバンド強度が弱かった。これは、酸化グラフェンによる被覆を支持していると考えられる。 (Analysis of carbon-modified boron nitride with graphene oxide layer by micro Raman spectroscopy)
Ten particles were randomly selected from the carbon-modified boron nitride particles produced in Example 1, and the microscopic Raman spectrum was measured (measuring device: Horiba XploRA). A 1590 cm −1 band derived from graphene oxide and boron nitride derived The 1360 cm −1 band was mapped. For all the particles, a band of 1590 cm −1 was detected on the majority of the observed particle surface, and therefore it is considered that the boron nitride particles have a graphene oxide layer on the entire surface. Further, the band intensity at 1360 cm −1 was weak where the band intensity was 1590 cm −1 . This is considered to support the coating with graphene oxide.
（Ｘ線光電子分光による酸化グラフェン層を有するカーボン修飾窒化ホウ素の分析）
　酸化グラフェンと実施例１で作製したカーボン修飾窒化ホウ素について、Ｘ線光電子分光を用いて酸化グラフェンの吸着前後変化を分析した（測定装置：ＵＬＶＡＣ　ＰＨＩ　５０００）。Ｃ１ｓスペクトルにおいて、未吸着の酸化グラフェンに対して窒化ホウ素上の酸化グラフェン層にはＣ－Ｏ結合に帰属されるピーク強度の著しい減少とＣ－Ｂ結合およびＣ－Ｎ結合とみられる新たなピークがみられた。酸化グラフェンは窒化ホウ素に吸着することによって、何らかの化学的変化を起こしていると考えられる。 (Analysis of carbon-modified boron nitride with graphene oxide layer by X-ray photoelectron spectroscopy)
The graphene oxide and the carbon-modified boron nitride prepared in Example 1 were analyzed for changes before and after the adsorption of graphene oxide using X-ray photoelectron spectroscopy (measurement apparatus: ULVAC PHI 5000). In the C1s spectrum, the graphene oxide layer on boron nitride has a significant decrease in peak intensity attributed to the C—O bond and new peaks that appear to be CB and CN bonds, compared to unadsorbed graphene oxide. It was seen. Graphene oxide is considered to cause some chemical change by adsorbing to boron nitride.
（実施例５）
（カーボン修飾窒化ホウ素を含む樹脂組成物の作製３）
　ビスＡ型エポキシ（三菱化学製：Ｅｐ８２８）　２０重量部とフェノールノボラック（ＤＩＣ製：ＴＤ２０９０）１１重量部、２－エチル－４－メチルイミダゾール（ナカライテスク製：２Ｅ４ＭＺ）０．３重量部を乳鉢でよく混ぜ合わせ、さらに実施例１で作製したカーボン修飾ＵＨＰ－２　３８重量部、球状アルミナＣＢ　Ａ２０Ｓ　３１重量部を添加して乳鉢で均一になるまで混練して窒化ホウ素－アルミナ混合物を得た（窒化ホウ素添加量は３５ｖｏｌ％、アルミナ添加量は１５ｖｏｌ％、充填材総添加量は５０ｖｏｌ％）。得られた混合物を１２０℃で４分間乾燥し、真空プレス機にて１４０℃／２０ＭＰａ／５分、１８０℃／０．５ＭＰａ／２時間プレスを行い、硬化物を得た。
　続いて、べテル製サーモウェーブアナライザ　ＴＡ（周期加熱方式）を用いて厚み方向と平面方向の熱拡散率を測定し、硬化物の比熱と比重から厚み方向と平面方向の熱伝導率を算出した。 (Example 5)
(Preparation of resin composition containing carbon-modified boron nitride 3)
20 parts by weight of bis-A type epoxy (Mitsubishi Chemical: Ep828), 11 parts by weight of phenol novolac (DIC: TD2090), and 0.3 parts by weight of 2-ethyl-4-methylimidazole (Nacalai Tesque: 2E4MZ) are used in a mortar. Further, 38 parts by weight of carbon-modified UHP-2 prepared in Example 1 and 31 parts by weight of spherical alumina CB A20S were added and kneaded until uniform in a mortar to obtain a boron nitride-alumina mixture (nitriding) The boron addition amount is 35 vol%, the alumina addition amount is 15 vol%, and the total filler addition amount is 50 vol%). The obtained mixture was dried at 120 ° C. for 4 minutes, and pressed with a vacuum press at 140 ° C./20 MPa / 5 minutes and 180 ° C./0.5 MPa / 2 hours to obtain a cured product.
Subsequently, the thermal diffusivity in the thickness direction and the plane direction was measured using a Bethel thermowave analyzer TA (periodic heating method), and the thermal conductivity in the thickness direction and the plane direction was calculated from the specific heat and specific gravity of the cured product. .
（実施例６～８）
（カーボン修飾窒化ホウ素を含む樹脂組成物の作製２～５）
　球状アルミナ（昭和電工製ＣＢ　Ａ２０Ｓの添加量を表２に従って２５、３５、４０ｖｏｌ％にする以外は、実施例５と同様にしてエポキシ樹脂硬化物を作製し、厚み方向と平面方向の熱伝導率を算出した。 (Examples 6 to 8)
(Preparation of resin composition containing carbon-modified boron nitride 2-5)
Spherical alumina (A cured epoxy resin was prepared in the same manner as in Example 5 except that the amount of CB A20S manufactured by Showa Denko was changed to 25, 35, and 40 vol% according to Table 2, and the thermal conductivity in the thickness direction and the planar direction was produced. Was calculated.
（比較例３～６）
　窒化ホウ素を未修飾の六方晶窒化ホウ素（昭和電工製ショウビーエヌ（登録商標）ＵＨＰ－２）にする以外は表３に従って実施例５と同様にして窒化ホウ素添加量３５ｖｏｌ％、球状アルミナ添加量１５、２５、３５、４０　ｖｏｌ％のエポキシ樹脂硬化物を作製し、厚み方向と平面方向の熱伝導率を算出した。 (Comparative Examples 3 to 6)
Except for boron nitride being unmodified hexagonal boron nitride (Showa Denko Shown® UHP-2), boron nitride addition amount 35 vol%, spherical alumina addition amount in the same manner as in Example 5 according to Table 3 15, 25, 35, 40 vol% cured epoxy resin was prepared, and the thermal conductivity in the thickness direction and the planar direction was calculated.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表２及び表３に示すように、同一添加量である実施例５と比較例３、ならびに実施例６と比較例４を比較すると、カーボン修飾窒化ホウ素を用いた硬化物では、明らかに厚み方向、平面方向ともに熱伝導率が向上していた。厚み方向の熱伝導率は、実施例８で６１％の大きな向上がみられた。作製した硬化物において平面方向と厚み方向で熱伝導率が異なるのは、窒化ホウ素が平面方向に配向しているためと考えられる。実施例において、特に厚み方向の熱伝導率の向上がみられた要因としては、球状アルミナの添加により窒化ホウ素の平面配向が乱され、厚み方向への熱パスが増えたことと、窒化ホウ素表面と樹脂との親和性が改善された結果、両者界面の剥離による空隙生成が減ったことが考えられる。 As shown in Table 2 and Table 3, when Example 5 and Comparative Example 3 and Example 6 and Comparative Example 4 having the same addition amount are compared, the cured product using carbon-modified boron nitride clearly has a thickness direction. The thermal conductivity was improved in the plane direction. The heat conductivity in the thickness direction was greatly improved by 61% in Example 8. The reason why the thermal conductivity is different between the planar direction and the thickness direction in the produced cured product is considered to be because boron nitride is oriented in the planar direction. In the examples, the factors that particularly improved the thermal conductivity in the thickness direction were that the addition of spherical alumina disturbed the planar orientation of boron nitride, increasing the heat path in the thickness direction, and the surface of the boron nitride surface. As a result of improving the affinity between the resin and the resin, it is considered that void formation due to separation at the interface between the two has decreased.
（実施例９）
（カーボン修飾窒化ホウ素を含む樹脂組成物の作製６）
　無溶剤型シリコーン樹脂（信越化学工業製　ＫＮＳ－３２０Ａ）１．５６重量部に実施例１で作製したカーボン修飾窒化ホウ素２．１８重量部と硬化剤（信越化学工業製ＣＡＴ－ＰＬ－５０Ｔ）０．０３重量部を乳鉢でよく混ぜ合わせた。混合物をポリテトラフッ化エチレン製四角容器に入れて真空脱泡（室温３０分）した後、ポリテトラフッ化エチレン製板で混合物を押し広げながら蓋をして、８０℃３０分加熱して硬化させた。
　得られた硬化物を型枠から取り出してべテル製サーモウェーブアナライザ　ＴＡ（周期加熱方式）を用いて厚み方向の熱拡散率を測定し、硬化物の比熱と比重から厚み方向の熱伝導率を算出したところ、熱伝導率は１．３１Ｗ／（ｍ・Ｋ）であった。 Example 9
(Preparation of resin composition containing carbon-modified boron nitride 6)
Solvent-free silicone resin (KNS-320A manufactured by Shin-Etsu Chemical Co., Ltd.) 1.56 parts by weight and 2.18 parts by weight of carbon-modified boron nitride prepared in Example 1 and a curing agent (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) 0 .03 parts by weight were mixed well in a mortar. The mixture was put into a square container made of polytetrafluoroethylene and subjected to vacuum degassing (room temperature 30 minutes), then the lid was spread with a plate made of polytetrafluoroethylene, covered and heated at 80 ° C. for 30 minutes to be cured.
The obtained cured product is taken out from the mold, and the thermal diffusivity in the thickness direction is measured using Bethel Thermowave Analyzer TA (periodic heating method), and the thermal conductivity in the thickness direction is determined from the specific heat and specific gravity of the cured product. When calculated, the thermal conductivity was 1.31 W / (m · K).
（比較例７）
　カーボン修飾窒化ホウ素を無修飾の窒化ホウ素（昭和電工製ショウビーエヌ（登録商標）ＵＨＰ－２）にする以外は実施例９と同様にして硬化物を作製し、厚み方向の熱伝導率を算出したところ、熱伝導率は０．８２Ｗ／（ｍ・Ｋ）であった。実施例９と比較すると、カーボン修飾窒化ホウ素を用いた方が熱伝導率は高くなる結果となった。 (Comparative Example 7)
A cured product was prepared in the same manner as in Example 9 except that the carbon-modified boron nitride was changed to unmodified boron nitride (Showa Denko (registered trademark) UHP-2), and the thermal conductivity in the thickness direction was calculated. As a result, the thermal conductivity was 0.82 W / (m · K). Compared with Example 9, the heat conductivity was higher when carbon-modified boron nitride was used.
　本発明のカーボン修飾窒化ホウ素は、粒子表面にシート状カーボン層を有することにより樹脂との親和性が向上し、配合された樹脂組成物の流動性や窒化ホウ素と樹脂との界面接着性を改善することができる。それにより機械的強度と熱伝導性の優れた熱伝導性樹脂組成物を提供でき、各種装置の熱伝導材料、放熱材料として利用できる。
 

  The carbon-modified boron nitride of the present invention has a sheet-like carbon layer on the particle surface, thereby improving the affinity with the resin and improving the fluidity of the blended resin composition and the interfacial adhesion between the boron nitride and the resin. can do. Thereby, the heat conductive resin composition excellent in mechanical strength and heat conductivity can be provided, and can be used as a heat conductive material and a heat dissipation material for various devices.


Claims (6)

  1. 　窒化ホウ素粒子表面にシート状カーボン層を有する、カーボン修飾窒化ホウ素。 Carbon-modified boron nitride having a sheet-like carbon layer on the surface of boron nitride particles.
  2. 　前記シート状カーボン層が１層～２０層の酸化グラフェンである、請求項１に記載のカーボン修飾窒化ホウ素。 2. The carbon-modified boron nitride according to claim 1, wherein the sheet-like carbon layer is 1 to 20 layers of graphene oxide.
  3. 　前記シート状カーボン層が１層～２０層の還元型酸化グラフェンである、請求項１に記載のカーボン修飾窒化ホウ素。 2. The carbon-modified boron nitride according to claim 1, wherein the sheet-like carbon layer is 1 to 20 layers of reduced graphene oxide.
  4. 　請求項１から３のいずれかに記載のカーボン修飾窒化ホウ素と樹脂とを含む、高熱伝導性樹脂組成物。 A highly thermally conductive resin composition comprising the carbon-modified boron nitride according to any one of claims 1 to 3 and a resin.
  5. 　酸化グラフェン水分散液と窒化ホウ素粉末とを混合する工程、および
    　前記混合で得られた液から固体を回収して乾燥し、カーボン修飾窒化ホウ素を得る工程、
    　を含む、カーボン修飾窒化ホウ素の製造方法。     A step of mixing a graphene oxide aqueous dispersion and a boron nitride powder, and a step of recovering a solid from the liquid obtained by the mixing and drying to obtain a carbon-modified boron nitride,
    A method for producing carbon-modified boron nitride, comprising:
  6. 　前記カーボン修飾窒化ホウ素を還元剤で還元する工程をさらに含む、請求項５に記載のカーボン修飾窒化ホウ素の製造方法。
     
     

          The method for producing carbon-modified boron nitride according to claim 5, further comprising a step of reducing the carbon-modified boron nitride with a reducing agent.



PCT/JP2018/022717 2017-06-16 2018-06-14 Carbon-modified boron nitride, method for producing same, and highly heat-conductive resin composition WO2018230638A1 (en)

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