Composition

Abstract

To provide a composition which is excellent in heat conductivity.SOLUTION: A composition contains a first surface-modified inorganic substance obtained by surface-modifying fibers and an inorganic substance selected from the group consisting of an inorganic nitride and an inorganic oxide with a boronic acid compound, or a second surface-modified inorganic substance obtained by treating the inorganic matter with an oxidizing agent, and a water-soluble resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition.

Background Art

[0002] In electronic devices such as transformers, motors, and generators, in terms of the life and reliability of the electronic devices, it is required that the heat generated during operation can be efficiently dissipated to the outside. For example, as a method of enhancing the heat dissipation property of a motor, a method of covering a coil conductor disposed in a slot formed in a stator core, which is a member constituting the motor, with a thermally conductive electrical insulating paper is known.

[0003] As the above-mentioned thermally conductive electrical insulating paper, for example, Patent Document 1 discloses a thermally conductive electrical insulating paper containing an aramid fiber, an aramid pulp, a binder material, and a synergistic blend of a thermally conductive filler containing boron nitride and calcium carbonate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the present inventors examined the characteristics of the thermally conductive electrical insulating paper described in Patent Document 1, it was revealed that there is room for further improving the thermal conductivity.

[0006] Therefore, an object of the present invention is to provide a composition having excellent thermal conductivity.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0008] (1) A composition comprising a fiber and a first surface-modified inorganic substance in which an inorganic substance selected from the group consisting of an inorganic nitride and an inorganic oxide is surface-modified with a boronic acid compound, or a second surface-modified inorganic substance in which the inorganic substance is treated with an oxidizing agent, and a water-soluble resin. (2) A composition comprising a fiber and a specific inorganic substance containing at least one selected from the group consisting of an inorganic nitride and an inorganic oxide and having a contact angle with water of 110° or less, and a water-soluble resin. (3) The composition according to (1) or (2), having a porosity of less than 20%. (4) The composition according to any one of (1) to (3), wherein the fiber contains at least one selected from the group consisting of an aramid fiber and a cellulose fiber. (5) The composition according to (1), wherein the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance is 1 to 70% by volume based on the total volume of the composition. (6) The composition according to (1), wherein the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance is 5 to 30% by volume based on the total volume of the composition. (7) The composition according to (2), wherein the content of the specific inorganic substance is 1 to 70% by volume based on the total volume of the composition. (8) The composition according to (2), wherein the content of the specific inorganic substance is 5 to 30% by volume based on the total volume of the composition. (9) The composition according to any one of (1) to (8), wherein the water-soluble resin contains a repeating unit having at least one group selected from the group consisting of a hydroxyl group, an oxyalkylene group, a carboxy group, and an amide group. (10) The composition according to any one of (1) to (9), which is in a sheet form. [Effect of the Invention]

[0009] According to the present invention, a composition having excellent thermal conductivity can be provided. [Embodiments for Carrying Out the Invention]

[0010] Hereinafter, the present invention will be described in detail. In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. Also, in this specification, when there are two or more kinds of a certain component present, the "content" of that component means the total content of those two or more kinds of components. In this specification, in a numerical range described stepwise, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerically described stepwise range. Also, in the numerical range described in this specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0011] In this specification, "(meth)acrylamide" is a concept encompassing either or both of acrylamide and methacrylamide. The same applies to the terms "(meth)acryl", "(meth)acrylate", "(meth)acryloyl", and "(meth)acryloxy".

[0012] Also, the "organic group" in this specification refers to a group containing at least one carbon atom.

[0013] Also, in this specification, the "alkyl group" may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 30, more preferably 2 to 10. The above description regarding the alkyl group also applies to other groups such as alkoxy groups containing an alkyl group moiety. Also, examples of the "alkylene group" include groups obtained by removing one arbitrary hydrogen atom from the above alkyl group. In addition, in this specification, the "alkenyl group" may be linear, branched, or cyclic. The number of carbon atoms in the alkenyl group is preferably 2 to 30, more preferably 2 to 10. Specific examples of the alkenyl group include a vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group, and the like. Note that the above description regarding the alkenyl group also applies to other groups containing an alkenyl group moiety. Further, examples of the "alkenylene group" include groups obtained by removing one arbitrary hydrogen atom from the above alkenyl group.

[0014] In addition, in this specification, the number of carbon atoms in the "alkynyl group" is preferably 2 to 30, more preferably 2 to 10. Specific examples of the alkynyl group include an ethynyl group, 1-propynyl group, 1-butynyl group, 1-octynyl group, and the like.

[0015] In addition, in this specification, the "aryl group" may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 5 to 18, more preferably 5 to 10. Specific examples of the aryl group include a phenyl group, naphthyl group, anthryl group, phenanthryl group, indenyl group, acenaphthenyl group, fluorenyl group, pyrenyl group, and the like. Note that examples of the "arylene group" include groups obtained by removing one arbitrary hydrogen atom from the above aryl group.

[0016] In addition, in this specification, examples of the "heteroaryl group" include groups obtained by removing one hydrogen atom from a hydrogen atom on a heteroaromatic ring containing one or more heteroatoms selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. The above heteroaromatic ring may be monocyclic or polycyclic. Specific examples of the above heteroaromatic ring include pyrrole, furan, thiophene, pyrazole, imidazole, and the like. Note that examples of the "heteroarylene group" include groups obtained by removing one arbitrary hydrogen atom from the above heteroaryl group.

[0017] In this specification, when it is described as "may have a substituent", the type, position, and number of the substituent are not particularly limited. The number of substituents may be, for example, one, two, three, or more. Examples of the substituent may include monovalent non-metal atomic groups excluding hydrogen, and can be selected from, for example, the following substituent group Y. Substituent group Y: Halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N,N-dialkylamino group, N-arylamino group, N,N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N,N-dialkylcarbamoyloxy group, N,N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfinyl group, arylsulfinyl group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N'-alkylureido group, N',N'-dialkylureido group, N'-arylureido group, N',N'-diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N',N'-dialkyl-N-alkylureido group, N',N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N'-aryl-N-arylureido group, N',N'-diaryl-N-alkylureido group, N',N'-diaryl-N-arylureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxy group and its conjugate base group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N,N-dialkylcarbamoyl group, N-arylcarbamoyl group, N,N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (-SO3H) and its conjugate base group, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N,N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N,N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N,N-dialkylsulfamoyl group, N-arylsulfamoyl group, N,N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group, N-alkylsulfonylsulfamoyl group (-SO2NHSO2(alkyl)) and its conjugate base group, N-arylsulfonylsulfamoyl group (-SO2NHSO2(aryl)) and its conjugate base group, N-alkylsulfonylcarbamoyl group (-CONHSO2(alkyl)) and its conjugate base group, N-arylsulfonylcarbamoyl group (-CONHSO2(aryl)) and its conjugate base group, alkoxysilyl group (-Si(Oalkyl)3), aryloxysilyl group (-Si(Oaryl)3), hydroxysilyl group (-Si(OH)3) and its conjugate base group, phosphono group (-PO3H2) and its conjugate base group, dialkylphosphono group (-PO3(alkyl)2), diarylphosphono group (-PO3(aryl)2), alkylarylphosphono group (-PO3(alkyl)(aryl)), monoalkylphosphono group (-PO3H(alkyl)) and its conjugate base group, monoarylphosphono group (-PO3H(aryl)) and its conjugate base group, phosphonooxy group (-OPO3H2) and its conjugate base group, dialkylphosphonooxy group (-OPO3(alkyl)2), diarylphosphonooxy group (-OPO3(aryl)2), alkylarylphosphonooxy group (-OPO3(alkyl)(aryl)), monoalkylphosphonooxy group (-OPO3H(alkyl)) and its conjugate base group, monoarylphosphonooxy group (-OPO3H(aryl)) and its conjugate base group, cyano group, nitro group, aryl group, alkenyl group and alkynyl group. Further, these substituents may, if possible, combine with each other or with the substituted group to form a ring.,

[0018] In this specification, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity (also referred to as "molecular weight distribution") (Mw / Mn) are defined as polystyrene-equivalent values by GPC measurement using a GPC (Gel Permeation Chromatography) apparatus (HLC-8120GPC, manufactured by Tosoh Corporation) (solvent: tetrahydrofuran, flow rate (sample injection volume): 10 μL, column: TSK gel Multipore HXL-M (manufactured by Tosoh Corporation), column temperature: 40 °C, flow rate: 1.0 mL / min, detector: refractive index detector).

[0019] In this specification, "the solid content of the slurry" means all components excluding the solvent when the slurry contains a solvent (such as water, etc.). Note that even liquid components are regarded as solid content.

[0020] [First Composition] The first composition of the present invention is fibers and a first surface-modified inorganic substance in which an inorganic substance selected from the group consisting of inorganic nitrides and inorganic oxides is surface-modified with a boronic acid compound, or a second surface-modified inorganic substance in which the above inorganic substance is treated with an oxidizing agent, and a water-soluble resin.

[0021] The reason why the first composition having the above configuration can solve the problems of the present invention is not necessarily clear, but the present inventors presume as follows. Note that the mechanism by which the effect is obtained is not limited by the following presumption. In other words, even if the effect is obtained by a mechanism other than the following, it is included in the scope of the present invention. As a result of the present study, the inventors have clarified that when the dispersibility of inorganic substances (inorganic nitrides and inorganic oxides) in a composition is poor, voids are likely to occur within the composition, and as a result, the thermal conductivity decreases. On the other hand, in the first composition, by subjecting the inorganic substance to a predetermined surface treatment, the compatibility with the water-soluble resin, which is another component contained in the composition, is improved. As a result, it is presumed that the dispersibility of the fiber and the inorganic substance is also improved, the generation of voids is suppressed, and the thermal conductivity is improved.

[0022] Hereinafter, the fact that the first composition has more excellent thermal conductivity is also referred to as "the effect of the present invention is more excellent". Hereinafter, first, each component that the first composition may contain will be described in detail.

[0023] 〔Fiber〕 The first composition contains a fiber. Note that the fiber typically corresponds to a fine filamentous substance. The fiber may be either an organic fiber or an inorganic fiber, but an organic fiber is preferred. Specific examples of the fiber include, for example, aramid fiber (aromatic polyamide fiber), cellulose fiber, polyphenylene sulfide (PPS) fiber, polyester fiber, polyamide fiber, acrylic fiber, melamine fiber, polyether ether ketone (PEEK) fiber, and polyimide fiber. Among these, in terms of more excellent effects of the present invention, the fiber preferably contains at least one selected from the group consisting of cellulose fiber and aramid fiber, and more preferably contains aramid fiber in terms of more excellent heat resistance. Examples of the aramid fiber include para-aramid fibers such as poly-p-phenylene terephthalamide, poly-p-benzamide, poly-p-amide hydrazide, and poly-p-phenylene terephthalamide-3,4-diphenyl ether terephthalamide, and meta-aramid fibers such as poly-m-phenylene isophthalamide. Examples of the cellulose fiber include those obtained by highly beating cellulose fibers such as wood pulp and rayon using a homogenizer and a disk refiner, those obtained by defibrating using a water collision method, and those subjected to chemical treatment such as TEMPO oxidation method.

[0024] The average fiber diameter of the fiber is not particularly limited, but for example, 0.05 to 3000 μm is preferable, and 0.10 to 1000 μm is more preferable. The aspect ratio represented by the fiber length / fiber diameter of the fiber is not particularly limited, but for example, 1 to 10000 is preferable, and 10 to 5000 is more preferable. The specific surface area of the fiber is not particularly limited, but for example, 0.1 to 1000 m 2 / g is preferable, and 0.2 to 500 m 2 / g is more preferable.

[0025] The fibers may be used alone or in combination of two or more. The lower limit of the fiber content is preferably 5% by volume or more, more preferably 10% by volume or more, and still more preferably 12% by volume or more with respect to the total volume of the composition in terms of more excellent effects of the present invention. The upper limit of the fiber content is preferably 80% by volume or less, more preferably 75% by volume or less, and still more preferably 70% by volume or less with respect to the total volume of the composition in terms of more excellent effects of the present invention.

[0026] 〔First surface-modified inorganic substance or second surface-modified inorganic substance〕 The first composition contains a first surface-modified inorganic substance or a second surface-modified inorganic substance. The first composition may contain both the first surface-modified inorganic substance and the second surface-modified inorganic substance. In the first composition, the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance is preferably 1 to 70% by volume, more preferably 1 to 60% by volume, still more preferably 1 to 40% by volume, particularly preferably 1 to 30% by volume, and most preferably 5 to 30% by volume with respect to the total volume of the first composition. In particular, in the first composition, when the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance is 30% by volume or less with respect to the total volume of the first composition, the first composition is more excellent in bendability (less likely to crack when bent). Further, in the first composition, when the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance is 5% by volume or more with respect to the total volume of the first composition, the first composition is more likely to be excellent in thermal conductivity.

[0027] <The first surface-modified inorganic substance> The first surface-modified inorganic substance is a surface-modified inorganic substance in which an inorganic substance selected from the group consisting of inorganic nitrides and inorganic oxides is surface-modified with a boronic acid compound. Here, "surface-modified with a boronic acid compound" is intended to mean a state in which the boronic acid compound is adsorbed on the surface of the inorganic nitride or inorganic oxide. The form of adsorption is not particularly limited, as long as it is a bonded state. That is, it also includes a state in which a group obtained by desorbing a part of the boronic acid compound is bonded to the surface of the inorganic nitride or inorganic oxide. The bond may be any of a covalent bond, a coordination bond, an ionic bond, a hydrogen bond, a van der Waals bond, and a metal bond, but a covalent bond is preferred. Further, the surface modification with the boronic acid compound may be performed so as to form a monomolecular film on at least a part of the surface of the inorganic nitride or inorganic oxide.

[0028] In the first surface-modified inorganic substance, it is particularly preferred that the boronic acid compound reacts with an -NH2 group or -OH group that may be present on the surface of the inorganic nitride or inorganic oxide to form a bond represented by -NH-B- or a bond represented by -O-B-. Through such a bond, for example, when a compound represented by the following formula (I) is used as the boronic acid compound, an organic chain represented by Z-X- can be present on the surface of the inorganic nitride or inorganic oxide. The first surface-modified inorganic substance is preferably an inorganic nitride surface-modified with a boronic acid compound in terms of more excellent effects of the present invention. That is, the first composition preferably contains an inorganic nitride surface-modified with a boronic acid compound.

[0029] (Inorganic substance) Hereinafter, the inorganic substances (inorganic nitrides and inorganic oxides) contained in the first surface-modified inorganic substance will be described.

[0030] The shapes of the inorganic nitride and the inorganic oxide are not particularly limited, and examples thereof include particulate (e.g., rice grain shape, spherical shape, cubic shape, spindle shape, flaky shape, aggregated shape, and irregular shape), film shape, and plate shape.

[0031] Examples of the inorganic nitride include boron nitride (BN), carbon nitride (C3N4), silicon nitride (Si3N4), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), chromium nitride (Cr2N), copper nitride (Cu3N), iron nitride (Fe4N), iron nitride (Fe3N), lanthanum nitride (LaN), lithium nitride (Li3N), magnesium nitride (Mg3N2), molybdenum nitride (Mo2N), niobium nitride (NbN), tantalum nitride (TaN), titanium nitride (TiN), tungsten nitride (W2N), tungsten nitride (WN2), yttrium nitride (YN), and zirconium nitride (ZrN). Among them, boron nitride, silicon nitride, or aluminum nitride is preferable, and boron nitride is more preferable in terms of more excellent effects of the present invention. The inorganic nitride may be used alone or in combination of two or more.

[0032] Examples of the inorganic oxide include zirconium oxide (ZrO2), titanium oxide (TiO2), silicon oxide (SiO2), aluminum oxide (Al2O3), iron oxide (Fe2O3, FeO, Fe3O4), copper oxide (CuO, Cu2O), zinc oxide (ZnO), yttrium oxide (Y2O3), niobium oxide (Nb2O5), molybdenum oxide (MoO3), indium oxide (In2O3, In2O), tin oxide (SnO2), tantalum oxide (Ta2O5), tungsten oxide (WO3, W2O5), lead oxide (PbO, PbO2), bismuth oxide (Bi2O3), cerium oxide (CeO2, Ce2O3), antimony oxide (Sb2O3, Sb2O5), germanium oxide (GeO2, GeO), lanthanum oxide (La2O3), ruthenium oxide (RuO2), etc. Among them, titanium oxide, aluminum oxide, or zinc oxide is preferable, and aluminum oxide is more preferable in terms of more excellent effects of the present invention. The inorganic oxide may be used alone or in combination of two or more. Note that the inorganic oxide may be an oxide generated by oxidation of a metal prepared as a non-oxide in an environment or the like.

[0033] In addition, the inorganic nitride and inorganic oxide in the first surface-modified inorganic substance may be those subjected to surface modification treatment with an oxidizing agent or the like.

[0034] (Boronic acid compound) The boronic acid compound has a structure in which one or more hydroxyl groups of boric acid are substituted with an organic group such as a hydrocarbon group. The boronic acid compound usually adsorbs to an inorganic substance at the boron part to surface-modify the inorganic substance. Examples of the boronic acid compound include compounds represented by the following formula (I).

[0035] [Chemical formula]

[0036] In formula (I), Z represents an amino group, a thiol group, a hydroxyl group, an isocyanate group, a carboxy group, a carboxylic anhydride group, a polymerizable group, a hydrogen atom, a halogen atom, a quaternary ammonium group or a salt thereof, or a quaternary pyridinium group or a salt thereof. The hydroxyl group represented by Z is preferably a hydroxyl group directly bonded to an aromatic ring such as a phenyl group. The carboxylic anhydride group represented by Z is preferably a group obtained by removing any hydrogen atom from acid anhydrides such as maleic anhydride, phthalic anhydride, pyromellitic anhydride, and trimellitic anhydride. Examples of the polymerizable group represented by Z include ethylenically unsaturated groups (e.g., (meth)acryloyl group, etc.) and oxiranyl groups. Among them, Z is preferably an amino group, a thiol group, or a hydroxyl group.

[0037] X represents an (n + 1)-valent linking group. When the (n + 1)-valent linking group represented by X is a divalent linking group, the divalent linking group is not particularly limited, but is preferably a group composed of one or more selected from the group consisting of -O-, -CO-, -NH-, a divalent aliphatic hydrocarbon group which may have a substituent (preferably an alkylene group or an alkenylene group), an arylene group which may have a substituent, and a heteroarylene group which may have a substituent. The divalent linking group represented by X preferably contains at least one selected from the group consisting of a divalent aliphatic hydrocarbon group which may have a substituent, an arylene group which may have a substituent, and a heteroarylene group which may have a substituent, more preferably contains a phenylene group which may have a substituent, and still more preferably is an unsubstituted phenylene group.

[0038] When X is an (n + 1)-valent (where n represents an integer of 2 or more) linking group, specific examples of the (n + 1)-valent (where n represents an integer of 2 or more) linking group include groups obtained by further removing any n - 1 hydrogen atoms from the divalent linking group represented by X described above.

[0039] n represents an integer of 1 or more. n is preferably from 1 to 10, more preferably from 1 to 6, still more preferably from 1 to 3, and particularly preferably 1 or 2.

[0040] R 1 and R 2 each independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent (preferably an alkyl group, an alkenyl group, or an alkynyl group), an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. Also, R 1 and R 2 may be linked to each other to form a ring structure. R 1 and R 2 are preferably hydrogen atoms among others.

[0041] Examples of the boronic acid compound include the boronic acid compounds described in paragraphs

[0040] to

[0046] and paragraph

[0051] of International Publication No. 2017 / 131006.

[0042] In the first surface-modified inorganic substance, the total content of the inorganic nitride and the inorganic oxide is preferably 90% by mass or more, more preferably 99% by mass or more, still more preferably 99.5% by mass or more, with respect to the total mass of the first surface-modified inorganic substance. The upper limit is less than 100% by mass, and preferably 99.9999% by mass or less. In the first surface-modified inorganic substance, the content of the boronic acid compound is preferably 10% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, with respect to the total mass of the first surface-modified inorganic substance. The lower limit is more than 0% by mass, preferably 0.0001% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.01% by mass or more, and most preferably 0.1% by mass or more.

[0043] (Method for producing the first surface-modified inorganic substance) The first surface-modified inorganic substance can be easily produced by bringing an inorganic oxide or an inorganic nitride into contact with a boronic acid compound. The contact between the inorganic oxide or inorganic nitride and the boronic acid compound can be carried out, for example, by stirring a solution containing the inorganic nitride or inorganic oxide and the boronic acid compound. The solvent contained in the above solution is not particularly limited, but is preferably an aqueous solvent (for example, water). Further, the above solution may be a slurry further containing a water-soluble resin or its raw material monomer, and fibers. When the above solution is the above slurry, the first composition can be formed by performing necessary treatments (for example, drying treatment and heat treatment (polymerization treatment, etc.)).

[0044] <Second surface-modified inorganic substance> The second surface-modified inorganic substance is a surface-modified inorganic substance in which an inorganic substance selected from the group consisting of inorganic nitrides and inorganic oxides is modified with an oxidizing agent. That is, the second surface-modified inorganic substance is at least one or more surface-modified inorganic substances selected from the group consisting of an inorganic nitride treated with an oxidizing agent and an inorganic oxide treated with an oxidizing agent.

[0045] The second surface-modified inorganic substance is preferably an inorganic nitride or an inorganic oxide surface-modified by an oxidizing agent. In addition, the second surface-modified inorganic substance may be further surface-modified with a metal coupling agent after being surface-modified with an oxidizing agent. The metal coupling agent is a compound having a hydrolyzable group directly bonded to a metal atom. Examples of the above metal atoms include Si, Ti, Zr, and Al. Examples of the above hydrolyzable group include an alkoxy group (preferably having 1 to 10 carbon atoms) and a halogen atom such as a chlorine atom. The number of hydrolyzable groups directly bonded to the metal atom possessed by the metal coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, for example, it is 10000. It is also preferable that the metal coupling agent has a reactive group. The reactive group is preferably a group capable of crosslinking with a resin binder or its precursor as described later, for example. Specific examples of the reactive group include an epoxy group, an oxetanyl group, a vinyl group, a (meth)acryl group, a styryl group, an amino group, an isocyanate group, a mercapto group, and an acid anhydride group. The number of reactive groups possessed by the metal coupling agent is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no upper limit to the above number, for example, it is 10000. Examples of the metal coupling agent include a silane coupling agent, a titanium coupling agent, a zirconia coupling agent, an aluminum coupling agent, and a zirconium aluminate coupling agent. Among them, the metal coupling agent is preferably a silane coupling agent.

[0046] The second surface-modified inorganic substance can be produced, for example, by bringing an inorganic nitride or an inorganic oxide into contact with an oxidizing agent. Specific examples of the inorganic nitride and the inorganic oxide used include the same ones as the inorganic nitride and the inorganic oxide contained in the first surface-modified inorganic substance. The contact treatment of the inorganic nitride or the inorganic oxide with the oxidizing agent is preferably carried out in an aqueous solution with a pH of 12 to 14. In the above aqueous solution, the time for bringing the inorganic nitride or the inorganic oxide into contact with the oxidizing agent is preferably 0.5 to 10 hours. Also, the temperature of the above aqueous solution when bringing the inorganic nitride or the inorganic oxide into contact with the oxidizing agent is preferably, for example, 25 to 80°C.

[0047] In an aqueous solution, there is no limitation on the method of bringing an inorganic nitride or an inorganic oxide into contact with an oxidizing agent. For example, a method of mixing and bringing them into contact by treatment using a pulverizer or a disintegrator such as a rocking mill, a bead mill, a ball mill, a Henschel mixer, a jet mill, a starburst, and a paint conditioner; a method of bringing them into contact while stirring using a mechanical stirrer such as a three-one motor or a magnetic stirrer; and a method of bringing them into contact while circulating an aqueous solution of an oxidizing agent containing an oxidizing agent or the like through a cartridge filled with an inorganic nitride or an inorganic oxide by a pump can be mentioned.

[0048] After bringing an inorganic nitride or an inorganic oxide into contact with an oxidizing agent in the above aqueous solution, it is preferable to take out the treated inorganic nitride or inorganic oxide from the above aqueous solution. There is no limitation on the method of taking out the treated inorganic nitride or inorganic oxide from the above aqueous solution. For example, a method of filtering the above aqueous solution and separating the treated inorganic nitride or inorganic oxide as a filtrate can be mentioned.

[0049] The oxidizing agent is not particularly limited. For example, persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; nitrates such as cerium ammonium nitrate, sodium nitrate, and ammonium nitrate; peroxides such as hydrogen peroxide and tert-butyl hydroperoxide; manganese compounds such as potassium permanganate and manganese dioxide; chromium compounds such as potassium chromate and potassium dichromate; hypervalent iodine compounds such as potassium periodate and sodium periodate; quinone compounds such as benzoquinone, naphthoquinone, anthraquinone, and chloranil; amine oxide compounds such as N-methylmorpholine N-oxide, salts of halogen oxoacids such as sodium hypochlorite and sodium chlorite, and a double salt composed of potassium peroxymonosulfate·potassium hydrogen sulfate·potassium sulfate (OXONE manufactured by DuPont) can be mentioned. Among them, the oxidizing agent preferably contains a persulfate, and more preferably a persulfate. In addition, in order to assist the action of the oxidizing agent, a catalyst may be used separately from the oxidizing agent. Examples of the catalyst include divalent iron compounds (such as FeSO4) and trivalent iron compounds. Note that the oxidizing agent and / or the catalyst may be a hydrate. The oxidizing agent may be used alone or in combination of two or more.

[0050] There is no limitation on the contents of the inorganic nitride and the inorganic oxide in the aqueous solution. For example, with respect to 100 parts by mass of water in the aqueous solution, 0.1 to 100 parts by mass is preferable, 1 to 30 parts by mass is more preferable, and 3 to 20 parts by mass is still more preferable. In the aqueous solution, the content of water is preferably 20 to 99% by mass, more preferably 50 to 95% by mass, and still more preferably 65 to 90% by mass with respect to the total mass of the aqueous solution. In the aqueous solution, the content of the oxidizing agent is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 1 to 20 parts by mass with respect to 100 parts by mass of water in the aqueous solution. When the aqueous solution contains a catalyst, the content of the oxidizing agent is preferably 0.005 to 2 parts by mass, more preferably 0.01 to 2 parts by mass, and still more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of water in the aqueous solution. Note that the catalyst may be used alone or in combination of two or more. The aqueous solution preferably contains an alkali source in order to adjust the pH of the aqueous solution. Examples of the alkali source include inorganic bases such as alkali metal hydroxides (such as sodium hydroxide) and alkaline earth metal hydroxides; and organic bases.

[0051] The contact angle of the first surface-modified inorganic substance and the second surface-modified inorganic substance with water is preferably 110° or less, more preferably 100° or less, and still more preferably 90° or less. The lower limit of the contact angle is not particularly limited and is, for example, more than 0°. The contact angle of the first surface-modified inorganic substance and the second surface-modified inorganic substance with water is measured as follows. That is, the first surface-modified inorganic substance or the second surface-modified inorganic substance is placed in a 30 mmφ adapter for hand press, and pressed at a pressure of 600 kgf / cm 2 (5880 N / cm 2 ) for 1 minute to obtain a compressed powder. The contact angle with water is determined by measuring the contact angle between the obtained compressed powder and water using a contact angle meter (DM700) manufactured by Kyowa Interface Science Co., Ltd. The contact angle shall be the value of the contact angle 200 ms after forming a liquid droplet on the compressed powder. The temperature in the measurement environment is preferably 25°C, and the humidity is preferably 50%.

[0052] [Water-soluble resin] The first composition contains a water-soluble resin. In this specification, "water-soluble" means that the solubility in 100 g of water at pH 7.0 with a liquid temperature of 25°C is 0.1 g or more. Therefore, the water-soluble resin is intended to be a resin that satisfies the above solubility conditions. The solubility of the water-soluble resin in 100 g of water at pH 7.0 with a liquid temperature of 25°C is preferably 1 g or more, more preferably 5 g or more, and still more preferably 10 g or more. As the water-soluble resin, in terms of excellent affinity with water, it preferably contains a repeating unit having at least one group selected from the group consisting of a hydroxyl group, an oxyalkylene group, a carboxyl group, and an amide group (hereinafter also referred to as "predetermined hydrophilic group"). Also, the number of predetermined hydrophilic groups in the repeating unit is not particularly limited, and examples thereof include 1 to 6. The number of carbon atoms of the above oxyalkylene group is preferably, for example, 1 to 6, and more preferably 2 to 4. Specific examples of the oxyalkylene group include -OCH2-, -OCH2CH2-, -OCH2CH2CH2-, and -OCH2CH2CH2CH2-. In the repeating unit, the oxyalkylene group may be included as a polyoxyalkylene group. The above amide group may be cyclic (for example, a pyrrolidone group).

[0053] The water-soluble resin is not particularly limited, and examples thereof include (meth)acrylic resins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, polyethylene oxide resins, vinyl ether resins, and polyamide resins. Among them, (meth)acrylic resins are preferred. In the present specification, the (meth)acrylic resin means a resin having a repeating unit derived from a (meth)acrylic compound. Examples of the (meth)acrylic compound include (meth)acrylamide compounds, (meth)acrylic acid, and (meth)acrylate compounds.

[0054] The (meth)acrylamide compound is not particularly limited, and examples thereof include monofunctional (meth)acrylamide compounds such as (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N-2-hydroxyethyl(meth)acrylamide, and polyfunctional (meth)acrylamide compounds such as (meth)acrylamide compounds represented by the following formula (A). A preferred embodiment of the water-soluble resin includes a polymer polymerized from a raw material monomer containing at least a polyfunctional (meth)acrylamide compound represented by the following formula (A). Among them, a polymer polymerized from a raw material monomer containing at least a monofunctional (meth)acrylamide compound and a polyfunctional (meth)acrylamide compound represented by the following formula (A) is preferred.

[0055] [Chemical formula]

[0056] In the formula, R 20 represents a hydrogen atom or a methyl group. In addition, a plurality of R 20 may be the same or different from each other.

[0057] X represents a p-valent linking group. p represents an integer of 2 to 4. X is not particularly limited, and examples thereof include -O-, -S-, -NR A-CO-, and an alkylene group which may contain one or more divalent linking groups selected from the group consisting of the following formula (B), a group represented by the following formula (Z1), a group represented by the following formula (Z2), and the like. The number of carbon atoms of the alkylene group is not particularly limited, but is, for example, 1 to 100. The above R A represents a hydrogen atom or an alkyl group. R A The alkyl group represented by may be linear, branched, or cyclic. Also, R A The number of carbon atoms of the alkyl group represented by is preferably 1 to 6, more preferably 1 to 3. The alkyl group may have a substituent. The substituent that the alkyl group may have is not particularly limited, and examples thereof include the substituents exemplified in the above substituent group Y. R A is preferably a hydrogen atom among others.

[0058]

Chemical formula

[0059] In formula (B), R 20 represents a hydrogen atom or a methyl group. Also, * represents the bonding position.

[0060]

Chemical formula

[0061] In formula (Z1) and formula (Z2), T 1 ~T 7 each independently represents a single bond or a divalent linking group. The divalent linking group is not particularly limited, and examples thereof include an alkylene group having 1 to 10 carbon atoms which may contain one or more divalent linking groups selected from the group consisting of -O-, -S-, -NR A -, and -CO-. Among them, in terms of more excellent effects of the present invention, T 1 ~T 7As for each, independently, an alkylene group having 2 to 4 carbon atoms containing -O- is more preferable. Note that T 1 ~T 7 In, at the position adjacent to the nitrogen atom in the amide group specified in the above formula (A), it is preferable that a carbon atom is located. Further, in the groups represented by the formula (Z1) and the formula (Z2), R 24 represents a hydrogen atom or a substituent. R 24 The substituent represented by is not particularly limited, and examples thereof include the substituents exemplified in the above substituent group Y. Among them, an alkyl group (which may be linear, branched, or cyclic. The number of carbon atoms is preferably 1 to 10, more preferably 1 to 6.) is preferable. The above R 24 is preferably a hydrogen atom or an alkyl group (for example, having 1 to 6 carbon atoms, preferably having 1 to 3 carbon atoms).

[0062] The compound represented by the above formula (A) is preferably a compound represented by the following formula (A1) or a compound represented by the following formula (A2) in that the effects of the present invention are more excellent.

[0063]

Chemical formula

[0064] In the formula (A1), R 20 each independently represents a hydrogen atom or a methyl group. Note that a plurality of R 20 may be the same or different from each other. L 20 each independently represents -O-, an alkylene group having 2 to 4 carbon atoms, or a divalent linking group combining these. Note that L 20 in, at the position adjacent to the nitrogen atom in the amide group specified in the chemical formula, it is preferable that a carbon atom is located. That is, as the group adjacent to the nitrogen atom in the amide group, it is preferable that an alkylene group having 2 to 4 carbon atoms is located. Examples of the above-mentioned "divalent linking group formed by combining these" include alkylene groups having 2 to 4 carbon atoms containing -O- such as -OCH2CH2-, -OCH2CH2CH2-, -OCH2CH2CH2CH2-, -CH2OCH2-, -CH2OCH2CH2-, and -CH2OCH2CH2CH2-, and -(O-alkylene group (having 2 to 4 carbon atoms)) n -represented groups and the like. Here, n represents an integer of 2 or more. The upper limit is not particularly limited, but about 10 may be mentioned. Among them, L 20 is preferably an alkylene group having 2 to 4 carbon atoms containing -O-. In addition, a plurality of Ls present 20 may be the same as or different from each other.

[0065]

Chemical formula

[0066] In formula (A2), each R 20 independently represents a hydrogen atom or a methyl group. R 21 and R 23 each independently represent -O-, an alkylene group having 1 to 4 carbon atoms, or a divalent linking group formed by combining these. Note that in R 21 and R 23 , a carbon atom is usually located at the position adjacent to the nitrogen atom in the amide group explicitly shown in the chemical formula. As the group adjacent to the nitrogen atom in the amide group, an alkylene group having 1 to 4 carbon atoms is preferably located. Examples of the above-mentioned "divalent linking group formed by combining these" include alkylene groups having 1 to 4 carbon atoms containing -O- such as -OCH2-, -OCH2CH2-, -OCH2CH2CH2-, -OCH2CH2CH2CH2-, -CH2OCH2-, -CH2OCH2CH2-, and -CH2OCH2CH2CH2-, and -(O-alkylene group (having 1 to 4 carbon atoms)) n -represented groups and the like. Here, n represents an integer of 2 or more. The upper limit is not particularly limited, but about 10 may be mentioned. Among them, R21 and R 23 is more preferably, each independently, an alkylene group having 1 to 4 carbon atoms or an alkylene group having 1 to 4 carbon atoms containing -O-.

[0067] In formula (A2), R 22 represents -O-, an alkylene group having 1 to 4 carbon atoms, a group represented by the above formula (B), or a divalent linking group combining these. Examples of the above "divalent linking group combining these" include the groups described for the above R 21 and R 23 When combining the group represented by formula (B) with another group, an alkylene group having 1 to 4 carbon atoms is preferably bonded to the nitrogen atom in the group represented by formula (B). Among them, R 22 is more preferably an alkylene group having 1 to 4 carbon atoms, an alkylene group having 1 to 4 carbon atoms containing -O-, or a group represented by formula (B).

[0068] L 21 and L 22 each independently represents a single bond or a group represented by the above formula (B). R 22 When R 21 represents formula (B), L 22 and L

[0069] Hereinafter, specific examples of the polyfunctional (meth) acrylamide compound represented by formula (A) will be exemplified.

[0070]

Chemical formula

[0071] Examples of the (meth)acrylate compound include (meth)acrylate alkyl esters. Specific examples of the (meth)acrylate alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate.

[0072] The weight average molecular weight of the water-soluble resin is preferably from 1,000 to 400,000, more preferably from 3,000 to 300,000, and still more preferably from 5,000 to 200,000. The dispersity (Mw / Mn) of the water-soluble resin is preferably from 1 to 10, more preferably from 1 to 5.

[0073] The water-soluble resin may be used alone or in combination of two or more. The lower limit of the content of the water-soluble resin is preferably 10% by volume or more, more preferably 15% by volume or more, and still more preferably 20% by volume or more, based on the total volume of the composition, in terms of more excellent effects of the present invention. The upper limit of the content of the water-soluble resin is preferably 75% by volume or less, more preferably 70% by volume or less, and still more preferably 65% by volume or less, based on the total volume of the composition, in terms of more excellent effects of the present invention.

[0074] 〔Method for producing the first composition〕 The first composition is preferably produced using an aqueous slurry prepared by mixing a water-soluble resin or its raw material monomer, a first surface-modified inorganic substance or a second surface-modified inorganic substance, fibers, other optional components to be blended as necessary, and an aqueous solvent (preferably water). The content of the solid matter in the aqueous slurry is preferably from 0.1 to 60% by mass, more preferably from 0.5 to 50% by mass, and still more preferably from 1 to 40% by mass, based on the total mass of the aqueous slurry. Note that the solid content is intended to mean components that can constitute the first composition other than the aqueous solvent in the aqueous slurry. Even if the property of the above components is liquid, it is regarded as the solid content.

[0075] When mixing the above various components, the various components may be mixed all at once or sequentially. That is, the preparation of the aqueous slurry containing the first surface-modified inorganic substance may be, for example, a method of mixing a water-soluble resin or its raw material monomer, a boronic acid compound, at least one of an inorganic oxide and an inorganic oxide, a fiber, other optional components (a polymerization initiator, a curing catalyst, a curing accelerator, a polymerization inhibitor, and a filler, etc.) to be blended as necessary, and an aqueous solvent. There is no particular limitation on the method of mixing the components, and known methods can be used. As the mixing device used for mixing, a liquid dispersion machine is preferable, and examples thereof include stirrers such as a rotary-revolution mixer and a high-speed rotation shear type stirrer, a colloid mill, a roll mill, a high-pressure jet type disperser, an ultrasonic disperser, a bead mill, and a homogenizer. The mixing device may be used alone or in combination of two or more. Degassing treatment may be performed before, after, and / or simultaneously with the mixing. The above mixing may be carried out in the air or in an inert gas atmosphere. Further, the above mixing may be carried out under normal pressure or under reduced pressure.

[0076] In the method for producing the first composition, after preparing the aqueous slurry, it preferably has a step of forming a coating film of the aqueous slurry. In particular, when the aqueous slurry contains a curable component containing a raw material monomer of a water-soluble resin, it preferably further has a step of performing a heat treatment (polymerization treatment) on the above coating film. There is no particular limitation on the coating film forming method, and known methods (for example, a method using a paper making machine, a coating method using a roll coater, etc.) can be appropriately used. Note that when forming a coating film of the aqueous slurry, a drying treatment may be performed on the coating film. The drying temperature is preferably, for example, 80 to 120°C, and the drying time is preferably, for example, 60 to 180 minutes.

[0077] The heating temperature during the heat treatment (polymerization treatment) is not particularly limited, and for example, it may be appropriately selected within the range of 150 to 250 °C. Further, when performing the heat treatment, heat treatments at different temperatures may be carried out multiple times. When performing the heat treatment, it is preferably carried out on the coating film of the aqueous slurry in the form of a sheet. Specifically, for example, it is preferably carried out after forming a coating film of the aqueous slurry on a substrate. At this time, after bringing a different substrate into contact with the coating film of the aqueous slurry formed on the substrate, the heat treatment may be carried out. The first composition obtained after the heat treatment may or may not be separated from one or both of the substrates. Further, when performing the heat treatment, coating films of the aqueous slurry may be respectively formed on separate substrates, and the heat treatment may be carried out in a state where the obtained coating films are in contact with each other. The first composition obtained after the heat treatment may or may not be separated from one or both of the substrates.

[0078] The heat treatment may be terminated when the composition is in a semi-cured state. Further, after the composition is in a semi-cured state, the heat treatment may be further carried out to complete the curing. The heat treatment for making the composition in a semi-cured state (also referred to as "semi-curing treatment") and the heat treatment for completely curing (also referred to as "main curing treatment") may be carried out in separate steps.

[0079] For example, in the semi-curing treatment, after forming a coating film of the aqueous slurry on a substrate, the heat treatment may be directly carried out on the coating film on the substrate without pressure to obtain a first composition in a semi-cured state (also referred to as "semi-cured film" or "semi-cured sheet"), or the heat treatment may be carried out on the coating film on the substrate while using pressing in combination to obtain a semi-cured film. The obtained semi-cured film may be used as a heat conductive material, or the semi-cured film may be further subjected to the main curing treatment and then the completely cured film may be used as a heat conductive material. That is, the first composition may be in a semi-cured state or a completely cured state. In the main curing treatment, the semi-cured film may be heated without pressure as it is, or it may be heated after pressing or while pressing. There is no limitation on the press used for press working that may be carried out during the curing treatment such as semi-curing treatment and / or full-curing treatment. For example, a flat press or a roll press may be used. Regarding the production of a heat conductive material including a heat treatment (polymerization treatment), reference can also be made to "High Thermal Conductivity Composite Materials" (published by CMC, written by Yutaka Takezawa).

[0080] There is no particular limitation on the shape of the first composition, and it can be formed into various shapes according to the application. Typical shapes of the formed first composition include, for example, a sheet shape.

[0081] 〔Use of the first composition〕 The first composition can be applied as a heat dissipation material (heat conductive material) to various electronic devices such as transformers, motors, and generators. The first composition is preferably used as a thermally conductive electrical insulating paper for covering a coil conductor disposed in a slot formed in a stator core, which is a member constituting a motor. When the first composition is used as a heat dissipation material, the sheet-shaped first composition may be used in combination with another sheet-shaped support. Specifically, it is preferable to use the sheet-shaped first composition and another sheet-shaped support as a laminate. Examples of the sheet-shaped support include plastic films. Examples of the material of the plastic film include polyesters such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivatives, and silicone. The film thickness of the sheet-shaped first composition is preferably 100 to 500 μm, and more preferably 150 to 400 μm. Examples of the laminate include a structure in which the sheet-shaped first composition is disposed on one or both sides of another polymer film. An adhesive layer may further be provided between the sheet-shaped first composition and the other polymer film.

[0082] 〔Porosity of the first composition〕 The porosity of the first composition is preferably less than 20%, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 8% or less, in terms of more excellent effects of the present invention. The lower limit is not particularly limited, but is usually 0% or more. The porosity is determined based on the following formula (1). Formula (1) Porosity (%) = {(theoretical density - actual density) / theoretical density} × 100 Theoretical density: It is the density calculated from the specific gravity and volume ratio of the components of the composition (the first composition). Actual density: It is the density derived by actually measuring the mass and volume of the composition (the first composition).

[0083] [Thermal conductivity of the first composition] The thermal conductivity of the first composition is preferably 0.5 W / mK or more, more preferably 0.6 W / mK or more, and still more preferably 0.7 W / mK or more. The upper limit is not particularly limited, but is usually 40 W / mK or less.

[0084] [Volume resistivity of the first composition] The first composition preferably has insulation (electrical insulation). For example, the volume resistivity of the first composition at 23°C and 65% relative humidity is 10 10 Ω·cm or more is preferable, 10 12 Ω·cm or more is more preferable, 10 14 Ω·cm or more is still more preferable. The upper limit is not particularly limited, but is usually 10 18 Ω·cm or less.

[0085] [Second composition] The second composition of the present invention is fibers, at least one selected from the group consisting of inorganic nitrides and inorganic oxides, and a specific inorganic substance showing a contact angle with water of 110° or less, a water-soluble resin, and contains them.

[0086] Although it is not necessarily clear why the second composition having the above configuration can solve the problems of the present invention, the present inventors presume as follows. Note that the mechanism by which the effect is obtained is not limited by the following presumption. In other words, even if the effect is obtained by a mechanism other than the following, it is included in the scope of the present invention. As a result of the present inventors' recent studies, it has been clarified that when the dispersibility in a composition of an inorganic nitride and an inorganic oxide is poor, voids are likely to occur in the composition, and as a result, the thermal conductivity decreases. On the other hand, in the second composition, by using an inorganic nitride and an inorganic oxide adjusted to exhibit a predetermined contact angle, the compatibility with a water-soluble resin, which is another component contained in the composition, is improved. As a result, it is presumed that the dispersibility of the fiber and the inorganic substance is also improved, the generation of voids is suppressed, and the thermal conductivity is improved.

[0087] Hereinafter, the fact that the thermal conductivity of the second composition is more excellent is also referred to as "the effect of the present invention is more excellent".

[0088] Hereinafter, the second composition will be described. The second composition is the same as the first composition except that a specific inorganic substance is used instead of the first surface-modified inorganic substance and the second surface-modified inorganic substance. Therefore, the composition (components and formulation), production method, uses, etc. of the second composition are the same as those of the first composition except that a specific inorganic substance is used instead of the first surface-modified inorganic substance and the second surface-modified inorganic substance, and the preferred embodiments are also the same.

[0089] 〔Specific inorganic substance〕 The second composition contains a specific inorganic substance. The specific inorganic substance contains at least one selected from the group consisting of an inorganic nitride and an inorganic oxide, and is not particularly limited as long as the contact angle with water is 110° or less. The contact angle of the specific inorganic substance with water on the surface is 110° or less, preferably 100° or less, and more preferably 90° or less. The lower limit is not particularly limited and is, for example, more than 0°. The contact angle of the specific inorganic substance with water is measured as follows. That is, a specific inorganic substance is placed in a 30 mmφ adapter for a hand press, and pressed at a pressure of 600 kgf / cm 2 (5880 N / cm 2 ) for 1 minute to obtain a compacted powder. The contact angle of the obtained compacted powder with water is measured using a contact angle meter (DM700) manufactured by Kyowa Interface Science Co., Ltd., and the contact angle with water can be determined. The contact angle is read as the value of the contact angle 200 ms after a droplet is formed on the compacted powder. Note that the temperature in the measurement environment is preferably 25°C, and the humidity is preferably 50%.

[0090] As an example of the form of the specific inorganic substance, inorganic nitrides surface-modified with a surface modifier (preferably a boronic acid compound), and inorganic oxides surface-modified with a surface modifier (preferably a boronic acid compound) can be mentioned. Here, "surface-modified with a surface modifier" is intended to mean a state in which the surface modifier is adsorbed on the surface of the inorganic nitride or inorganic oxide. The form of adsorption is not particularly limited, as long as it is in a bonded state. That is, it also includes a state in which a group obtained by partial desorption of the surface modifier is bonded to the surface of the inorganic nitride or inorganic oxide. The bond may be any of a covalent bond, a coordination bond, an ionic bond, a hydrogen bond, a van der Waals bond, and a metal bond, but a covalent bond is preferred. Further, the surface modification with the surface modifier may be performed so as to form a monolayer on at least a part of the surface of the inorganic nitride or inorganic oxide.

[0091] As a specific example of the specific inorganic substance having the above form, the first surface-modified inorganic substance contained in the first composition can be mentioned. When the specific inorganic substance has the above structure, the total content of the inorganic nitride and the inorganic oxide in the specific inorganic substance is preferably 90% by mass or more, more preferably 99% by mass or more, and still more preferably 99.5% by mass or more, based on the total mass of the specific inorganic substance particles. The upper limit is less than 100% by mass, and preferably 99.9999% by mass or less. In the specific inorganic substance, the content of the surface modifier is preferably 10% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less, based on the total mass of the specific inorganic substance. The lower limit is more than 0% by mass, preferably 0.0001% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.01% by mass or more, and most preferably 0.1% by mass or more.

[0092] As another example of the form of the specific inorganic substance, there are inorganic nitrides surface-modified with an oxidizing agent and inorganic oxides surface-modified with an oxidizing agent. The surface modification method using an oxidizing agent for inorganic nitrides and inorganic oxides is as described above. Specific examples of the specific inorganic substance having the above form include the second surface-modified inorganic substance contained in the first composition.

[0093] In addition, as the form of the specific inorganic substance, in addition to the above, there are inorganic nitrides surface-modified by plasma treatment and inorganic oxides surface-modified by plasma treatment. The above plasma treatment may be carried out under atmospheric pressure or under reduced pressure (500 Pa or less, preferably 0 to 100 Pa).

[0094] In the plasma treatment, examples of the gas to be in a plasma state include O2 gas, Ar gas, N2 gas, H2 gas, He gas, and a mixed gas containing one or more of these. It is preferable that at least O2 gas is contained in the above gas, more preferably 60 to 100% by volume of the above gas is O2 gas, still more preferably 90 to 100% by volume of the above gas is O2 gas, and particularly preferably substantially O2 gas alone. That is, the plasma treatment is preferably an oxygen plasma treatment.

[0095] The output in the plasma treatment is preferably 50 to 1000 W, more preferably 70 to 500 W, and still more preferably 100 to 300 W, whether carried out under atmospheric pressure or under reduced pressure. When performing plasma treatment under atmospheric pressure, the plasma treatment time is preferably 0.2 to 30 hours, more preferably 4 to 8 hours. When performing plasma treatment under reduced pressure, the plasma treatment time is preferably 0.2 to 10 hours, more preferably 0.2 to 3 hours. The plasma treatment may be performed continuously or intermittently. When performed intermittently, it is preferable that the total treatment time is within the above range. When performing plasma treatment, the treatment temperature is preferably 0 to 200 °C, more preferably 15 to 100 °C.

[0096] In the second composition, the total content of the specific inorganic substances is preferably 1 to 70% by volume, more preferably 1 to 60% by volume, still more preferably 1 to 40% by volume, particularly preferably 1 to 30% by volume, and most preferably 5 to 30% by volume with respect to the total volume of the second composition. In particular, in the second composition, when the total content of the specific inorganic substances is 30% by volume or less with respect to the total volume of the second composition, the second composition is more excellent in bendability (less likely to crack when bent). Also, in the second composition, when the total content of the specific inorganic substances is 5% by volume or more with respect to the total volume of the second composition, the thermal conductivity of the second composition is likely to be more excellent. The specific inorganic substances may be used alone or in combination of two or more.

[0097] 〔Porosity of the second composition〕 The porosity of the second composition is preferably less than 20%, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 8% or less in terms of more excellent effects of the present invention. The lower limit is not particularly limited, but is usually 0% or more. The porosity is determined based on the above formula (1).

[0098] 〔Thermal conductivity of the second composition〕 The thermal conductivity of the second composition is preferably 0.5 W / mK or more, more preferably 0.6 W / mK or more, still more preferably 0.7 W / mK or more. The upper limit is not particularly limited, but is usually 40 W / mK or less.

[0099] [Volume Resistivity of the Second Composition] The second composition is preferably insulating (electrically insulating). For example, the volume resistivity of the first composition at 23°C and 65% relative humidity is preferably 10 10 Ω·cm or more, more preferably 10 12 Ω·cm or more, and still more preferably 10 14 Ω·cm or more. The upper limit is not particularly limited, but is usually 10 18 Ω·cm or less. [Examples]

[0100] The present invention will be described in more detail based on the following examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0101] [Preparation of Composition] [Preparation of Compositions of Examples 1 to 6] Aramid fiber (product name Aramid Pulp 1094 (manufactured by Teijin)), boron nitride 1 (described as "BN1" in the table. "BORONID Cooling Filer AGGLOMERATE 50" (manufactured by 3M)), boric acid 1 (surface modifier. p-hydroxyphenylboronic acid (manufactured by Fujifilm Wako Pure Chemical Corporation)), FOM-03006 (raw material of water-soluble resin 1. Tetrafunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), N,N-dimethylacrylamide (raw material of water-soluble resin 1. Monofunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), polymerization initiator (product name V-50 (manufactured by Fujifilm Wako Pure Chemical Corporation)), and water were mixed in a predetermined ratio to prepare an aqueous slurry having a solid content of about 6% by mass. When the amount of boron nitride 1 used in the preparation of the above aqueous slurry was 100% by mass, the amount of boric acid 1 used was 1% by mass. Next, the above aqueous slurry was applied onto a 10 cm × 15 cm PET film (Cosmo Shine, manufactured by Toyobo Co., Ltd., film thickness 50 μm) at 4000 g / m 2It was applied so as to obtain a coating film having a uniform planar shape. Then, the obtained PET film with the coating film was subjected to a heat treatment (semi-curing treatment) at 90 °C for 150 minutes using a hot plate to evaporate the moisture in the coating film. Thereafter, the PET film with the coating film was subjected to a pressing treatment at 17.5 MPa for 5 minutes at a temperature of 188 °C to obtain a PET film with a cured film. After the obtained PET film with the cured film was cooled to room temperature, the cured film was peeled off from the PET film to obtain a thermal conductive material (composition) in the form of a self-supporting film of about 300 μm. Table 1 shows the composition of the obtained thermal conductive material (composition).

[0102] [Preparation of Compositions of Examples 7 to 11] Aramid fiber (product name: Aramid pulp 1094 (manufactured by Teijin)), modified boron nitride 1 manufactured by the method described below, FOM-03006 (raw material of water-soluble resin 1, tetrafunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), N,N-dimethylacrylamide (raw material of water-soluble resin 1, monofunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), polymerization initiator (product name: V-50 (manufactured by Fujifilm Wako Pure Chemical Corporation)), and water were mixed in a predetermined ratio to prepare an aqueous slurry having a solid content of about 6% by mass. Next, the above aqueous slurry was applied onto a 10 cm × 15 cm PET film (Cosmo Shine, manufactured by Toyobo Co., Ltd., film thickness 50 μm) at 4000 g / m 2 so as to obtain a coating film having a uniform planar shape. Then, the obtained PET film with the coating film was subjected to a heat treatment (semi-curing treatment) at 90 °C for 150 minutes using a hot plate to evaporate the moisture in the coating film. Thereafter, the PET film with the coating film was subjected to a pressing treatment at 17.5 MPa for 5 minutes at a temperature of 188 °C to obtain a PET film with a cured film. After the obtained PET film with the cured film was cooled to room temperature, the cured film was peeled off from the PET film to obtain a thermal conductive material (composition) in the form of a self-supporting film of about 300 μm. Table 1 shows the composition of the obtained thermal conductive material (composition).

[0103] (Method for Producing Modified Boron Nitride 1) 1 g of boron nitride was added to 400 ml of an aqueous NaOH solution (40 g of NaOH / 400 ml of water) and stirred. To the above aqueous NaOH solution, 100 ml of an aqueous sodium persulfate solution (9.6 g of sodium persulfate / 100 ml of water) was further added. Then, the temperature of the above aqueous NaOH solution was raised to 50 °C and stirred for another 3 hours. A three-one motor manufactured by Shin-Tong Science Co., Ltd. was used for stirring at 150 rpm. After cooling the above aqueous NaOH solution to room temperature, the boron nitride particles in the aqueous NaOH solution were filtered off, and the filtered boron nitride particles were washed with water (500 ml) and acetonitrile (250 ml) to obtain surface-oxidized modified boron nitride particles 1.

[0104] 〔Preparation of Compositions of Examples 12 to 16〕 Aramid fiber (product name: Aramid pulp 1094 (manufactured by Teijin)), surface-modified boron nitride particles 2 produced by the method described below, FOM-03006 (raw material of water-soluble resin 1. Tetrafunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), N,N-dimethylacrylamide (raw material of water-soluble resin 1. Monofunctional acrylamide-based monomer (manufactured by Fujifilm Wako Pure Chemical Corporation)), polymerization initiator (product name: V-50 (manufactured by Fujifilm Wako Pure Chemical Corporation)), and water were mixed in a predetermined ratio to prepare an aqueous slurry with a solid content of about 6% by mass. Next, the above aqueous slurry was applied onto a 10 cm × 15 cm PET film (Cosmo Shine, manufactured by Toyobo Co., Ltd., film thickness 50 μm) at 4000 g / m 2 so as to form a coating film having a uniform planar shape. Then, the obtained PET film with the coating film was heat-treated (semi-curing treatment) at 90 °C for 150 minutes using a hot plate to evaporate the moisture in the coating film. Thereafter, the PET film with the coating film was subjected to a pressing treatment at 17.5 MPa for 5 minutes at a temperature of 188 °C to obtain a PET film with a cured film. After cooling the obtained PET film with the cured film to room temperature, the cured film was peeled off from the PET film to obtain a thermal conductive material (composition) in the form of a self-standing film of about 300 μm. Table 1 shows the composition of the obtained thermal conductive material (composition).

[0105] (Method for Producing Surface-Modified Boron Nitride Particles 2) 1 g of boron nitride was added to 400 ml of water containing 40 g of NaOH and stirred. To the above NaOH solution, 100 ml of water containing 9.6 g of sodium persulfate was further added. Then, the temperature of the above NaOH solution was raised to 50 °C and stirred for another 3 hours. A three-one motor manufactured by Shinto Kagaku Co., Ltd. was used for stirring at 150 rpm. After the above NaOH solution was cooled to room temperature, the boron nitride particles in the NaOH solution were collected by filtration. The collected boron nitride particles were washed with 500 ml of water and 250 ml of acetonitrile to obtain surface-oxidized boron nitride particles 1. The obtained boron nitride particles 1 were stirred in 100 ml of acetonitrile, and 1.25 g of a hydrolysis-adjusted solution of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: X12-984S) was further added to the above acetonitrile. The above acetonitrile was stirred at room temperature for 3 hours for an adsorption treatment. After the boron nitride particles 1 in the above acetonitrile were collected by filtration, the collected boron nitride particles 1 were washed with 100 ml of acetonitrile and dried in an oven at 40 °C to obtain surface-modified boron nitride particles 2. The hydrolysis-adjusted solution of the silane coupling agent was prepared by mixing 1 g of the silane coupling agent, 500 μl of ethanol, 500 μl of 2-propanol, 720 μl of water, and 100 μl of acetic acid and stirring for 1 hour. Also, "X12-984S" is a polymer-type silane coupling agent having an epoxy group and an ethoxysilyl group.

[0106] 〔Preparation of Compositions of Examples 17 to 19〕 A heat-conductive material (composition) was obtained according to the same procedure as in Example 1, except that N,N-dimethylacrylamide was changed to FOM-03010 (a raw material of water-soluble resin 2, a monofunctional acrylamide-based monomer, manufactured by Fujifilm Wako Pure Chemical Corporation)) and the composition was made according to the description in Table 1.

[0107] 〔Preparation of Composition of Comparative Example 1〕 A thermal conductive material (composition) of Comparative Example 1 was prepared in the same procedure as in Examples 1 to 6, except that boron nitride 1 and boric acid 1 were not added. Table 1 shows the composition of the obtained thermal conductive material (composition).

[0108] [Preparation of Composition of Comparative Example 2] A thermal conductive material (composition) of Comparative Example 2 was prepared in the same procedure as in Examples 1 to 6, except that boric acid 1 was not added. Table 1 shows the composition of the obtained thermal conductive material (composition).

[0109] [Preparation of Composition of Comparative Example 3] A mixture of 37.3% by volume of p-aramid pulp (specific surface area 12 to 15 m 2 / g), 61.6% by volume of acrylic latex, and 1.1% by volume of boron nitride was dispersed in water to form an aqueous slurry having a solid content of about 0.06 to 0.9% by mass. As the above acrylic latex, Hycar 26362 obtained from The Lubrizol Corp. (Cleveland, OH) was used. Next, using the above aqueous slurry, dehydration was performed by the screen part and press part (Williams Standard Pulp Testing Apparatus) of a paper-making machine. Then, the sheet obtained from the aqueous slurry was dried. Thereafter, a thermal conductive material (composition) was prepared by calendering between steel rolls at a pressure of 1000 PLI (179 kg / cm), a temperature of 370°F (188°C) to 380°F (193°C), and a speed of 3 ft / min (0.9 m / min).

[0110] [Preparation of Composition of Comparative Example 4] The raw materials of water-soluble resin 1 (FOM-03006 and N,N-dimethylacrylamide) were changed to the disc-shaped liquid crystal compound represented by the following structural formula described in paragraph 0125 of International Publication No. 2017 / 131006, and a thermal conductive material (composition) was prepared according to the same procedure as in Comparative Example 2, except that the composition ratio was changed as shown in Table 1.

[0111] [Chemical Formula]

[0112] [Preparation of the Composition of Comparative Example 5] A heat conductive material (composition) of Comparative Example 5 was prepared in the same procedure as in Comparative Example 2, except that aramid fibers were not added and the composition ratio described in Table 1 was used. Table 1 shows the composition of the obtained heat conductive material (composition).

[0113] [Measurement of Water Contact Angle] The water contact angles of unmodified boron nitride particles, surface-modified boron nitride particles surface-modified with a boronic acid compound, modified boron nitride 1, and surface-modified boron nitride particles 2 contained in the heat conductive materials (compositions) of the examples and comparative examples were measured, respectively. Regarding the surface-modified boron nitride particles surface-modified with the boronic acid compound used in Examples 1 to 6 and Examples 17 to 19, measurement samples were prepared according to the following procedure. Using the various particles described above, the contact angle was measured according to <Measurement of Contact Angle> described below. [Procedure for Preparing Measurement Sample] Boron nitride 1 (1.00 g), boronic acid 1 (surface modifier, p-hydroxyphenylboronic acid (manufactured by Fujifilm Wako Pure Chemical Corporation)) (0.01 g), and water were mixed in a predetermined ratio to prepare an aqueous slurry having a solid content of about 6% by mass. Surface-modified boron nitride particles surface-modified with a boronic acid compound were separated from the obtained aqueous slurry.

[0114] [Measurement of Contact Angle] The measurement sample (unmodified boron nitride particles, surface-modified boron nitride particles surface-modified with a boronic acid compound, modified boron nitride 1, and surface-modified boron nitride particles 2) was placed in a 30 mmφ adapter for hand pressing, and 600 kgf / cm 2 (5880 N / cm 2It was pressed for 1 minute at the pressure of ) to obtain a compacted powder. The contact angle between the compacted powder and water was measured using a contact angle meter (DM700) manufactured by Kyowa Interface Science Co., Ltd. The contact angle was read as the value of the contact angle 200 ms after a liquid droplet was formed on the compacted powder. The measurement was carried out in an environment with a temperature of 25 °C and a humidity of 50%. The results are shown in Table 1.

[0115] [Measurement and Evaluation] The following measurements and evaluations were carried out on the obtained heat conduction material (composition). [Measurement of Porosity] The porosity was determined based on the following formula (1). Formula (1) Porosity (%) = {(Theoretical density - Actual density) / Theoretical density} × 100 Theoretical density: It is the density calculated from the specific gravity and volume ratio of the components of the heat conduction material (composition). Actual density: It is the density derived by actually measuring the mass and volume of the heat conduction material (composition). The results are shown in Table 1.

[0116] [Measurement of Thermal Conductivity] The thermal conductivity was measured by the following method. (1) Using "I-Face Mobile 1u" manufactured by I-Face Co., Ltd., the thermal diffusivity in the thickness direction was measured. (2) Using a balance "XS204" manufactured by METTLER TOLEDO Co., Ltd. (using the "Solid Specific Gravity Measurement Kit"), the specific gravity was measured. (3) Using "DSC320 / 6200" manufactured by Seiko Instruments Inc., under the temperature rising condition of 10 °C / min, the specific heat at 25 °C was determined using the software of DSC7. (4) The thermal conductivity was calculated by multiplying the obtained thermal diffusivity by the specific gravity and the specific heat. The results are shown in Table 1.

[0117] [Bending Test] Test pieces were cut out from the obtained heat conduction material (composition) to have a width of 15 mm and a length of 150 mm. Grip both ends of the obtained test piece in the longitudinal direction, and conduct a bending test under the conditions of load: 1 N, number of bending cycles: 10 times, bending radius R = 1.0, and speed: 60 cpm, and evaluate according to the following evaluation criteria. The results are shown in Table 1. <Evaluation Criteria> "A": No cracks at all. "B": There were very slight cracks. "C": There were cracks, but the cracks were not obvious. "D": There were cracks, and the cracks began to be obvious. "E": The cracks were extremely obvious.

[0118] The following shows Table 1. The content of each component of the heat conductive material (composition) shown in the table represents the volume % with respect to the total volume of the composition. Also, in the table, "surface oxidation treatment" intends surface modification using an oxidizing agent. Also, in the table, "Si agent treatment" means that after surface modification using an oxidizing agent, surface modification using a silane coupling agent was further performed.

[0119]

Table 1

[0120] From the results in Table 1, it is clear that the compositions of the examples (the first composition and the second composition) are excellent in thermal conductivity. Also, from the comparison of the examples, it was confirmed that when the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance in the first composition is 30 volume % or less with respect to the total volume of the first composition, the bendability of the first composition is more excellent. In particular, when the total content of the first surface-modified inorganic substance and the second surface-modified inorganic substance in the first composition is 5 - 30 volume % with respect to the total volume of the first composition, it was confirmed that both the thermal conductivity and the bendability of the first composition are excellent. Also, from the comparison of the examples, it was confirmed that when the first composition contains the first surface-modified inorganic substance, the thermal conductivity of the first composition is more excellent.

[0121] Also, from the comparison of the examples, it was confirmed that when the content of the specific inorganic substance in the second composition is 30% by volume or less with respect to the total volume of the second composition, the bendability of the second composition is more excellent. In particular, when the total content of the specific inorganic substance in the second composition is 5 to 30% by volume with respect to the total volume of the second composition, it was confirmed that both the thermal conductivity and the bendability of the second composition are excellent.

Claims

1. A fiber, a first surface-modified inorganic material in which an inorganic material selected from the group consisting of an inorganic nitride and an inorganic oxide is surface-modified with a boronic acid compound, or a second surface-modified inorganic material in which the inorganic material is treated with an oxidizing agent, and a water-soluble resin, and a composition containing the same.

2. A fiber, a specific inorganic material containing at least one selected from the group consisting of an inorganic nitride and an inorganic oxide and showing a contact angle with water of 110° or less, and a water-soluble resin, and a composition containing the same.

3. The composition according to claim 1 or 2, having a porosity of less than 20%.

4. The composition according to claim 1 or 2, wherein the fiber contains at least one selected from the group consisting of an aramid fiber and a cellulose fiber.

5. The composition according to claim 1, wherein the total content of the first surface-modified inorganic material and the second surface-modified inorganic material is 1 to 70% by volume based on the total volume of the composition.

6. The composition according to claim 1, wherein the total content of the first surface-modified inorganic material and the second surface-modified inorganic material is 5 to 30% by volume based on the total volume of the composition.

7. The composition according to claim 2, wherein the content of the specific inorganic material is 1 to 70% by volume based on the total volume of the composition.

8. The composition according to claim 2, wherein the content of the specific inorganic material is 5 to 30% by volume based on the total volume of the composition.

9. The composition according to claim 1 or 2, wherein the water-soluble resin contains a repeating unit having at least one group selected from the group consisting of a hydroxyl group, an oxyalkylene group, a carboxy group, and an amide group.

10. The composition according to claim 1 or 2, which is in a sheet form.

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