Method for producing nitride filler coated with silicone-containing compound having silanol group, and method for producing silica-coated nitride filler coated with silicone-containing compound having silanol group

Abstract

Provided are: a method for producing a nitride filler coated with an organosilicon-containing compound having a silanol group; and a method for producing a silica-coated nitride filler coated with an organosilicon-containing compound having a silanol group, with which it is possible to control the reduction in viscosity of a slurry obtained by mixing with a resin monomer. The method for producing an organosilicon-containing compound-coated nitride filler having a silanol group includes: a first 1A step in which the surface of a nitride filler is coated with an organosilicon compound having a specific structure to obtain an organosilicon-containing compound-coated nitride filler; and a second 2A step in which the surface of the organic silicon compound-coated nitride filler is treated with an alkaline substance to obtain an organic silicon compound-coated nitride filler having a silanol group on the surface. Alternatively, the method includes a first P step in which an organosilicon compound and a basic substance are caused to coexist in the same atmosphere, and the organosilicon compound and the basic substance are treated simultaneously to coat the surface of the nitride filler, thereby obtaining an organosilicon-containing compound-coated nitride filler having a silanol group on the surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a silanol group-containing organosilicon compound-coated nitride filler and a method for producing the same, and a silanol group-containing organosilicon compound-coated silicon dioxide-coated nitride filler and a method for producing the same. BACKGROUND

[0002] Nitride fillers have high thermal conductivity and excellent electrical insulation. Therefore, nitride fillers are expected to be used as fillers for resin compositions used in products such as heat sinks and sealing materials for electronic parts. Among them, aluminum nitride causes hydrolysis by reacting with moisture, and deteriorates to aluminum hydroxide having low thermal conductivity. In addition, aluminum nitride also generates ammonia having corrosive properties at the time of hydrolysis.

[0003] Hydrolysis of aluminum nitride also proceeds by moisture in the atmosphere. Therefore, products to which aluminum nitride is added under conditions of high temperature and high humidity not only cause a decrease in moisture resistance and thermal conductivity, but also cause performance deterioration such as corrosion due to ammonia generated by hydrolysis of aluminum nitride.

[0004] As a technology for achieving an improvement in moisture resistance of aluminum nitride, a method of forming a layer composed of Si-Al-O-N on the surface of aluminum nitride powder (for example, see Patent Literature 1), a method of forming a coating layer on the surface of aluminum nitride powder using a silicate treatment agent and a coupling agent (for example, see Patent Literature 2), a method of treating with a silicate treatment agent to leave an organic group on the surface of aluminum nitride powder (for example, see Patent Literature 3), a method of surface-modifying the surface of aluminum nitride particles using a specific acidic phosphate ester (for example, see Patent Literature 4), and a method of maintaining more excellent moisture resistance and thermal conductivity (for example, see Patent Literature 5) have been proposed.

[0005] The moisture-resistant aluminum nitride powder of Patent Literature 1 is formed by coating a silicate layer on the surface of aluminum nitride powder and then firing at a high temperature of 350 to 1000°C, thereby forming a layer composed of Si-Al-O-N on the surface.

[0006] The aluminum nitride-based powder of Patent Literature 2 is formed by surface treatment with a silicate treatment agent and a coupling agent and then high-temperature heat treatment, thereby forming a coating layer on the surface. The aluminum nitride powder of Patent Literature 3 is surface-treated with a silicate treatment agent and then heat-treated at a temperature of not more than 90°C, thereby leaving an organic group and improving compatibility with a resin.

[0007] The surface-modified particles of Patent Literature 4 are aluminum nitride particles surface-modified using a specific acidic phosphate ester to improve moisture resistance. The surface-modified particles of Patent Literature 5 are formed by coating with an extremely thin, homogeneous, and dense silica film to form excellent moisture-resistant aluminum nitride particles.

[0008] Further, boron nitride is also used for various heat dissipation members due to its high thermal conductivity, there is no problem of moisture resistance like aluminum nitride, and further, it is widely used for various uses while exerting a feature of low dielectric constant. However, even boron nitride, primary particles thereof are plate-like, and originally the effective active points of a silane coupling agent are few, and are concentrated on the end face, and particularly when boron nitride is filled at a high rate, there are problems that the compatibility with a resin, the slurry viscosity easily becomes high.

[0009] Prior art documents

[0010] Patent documents

[0011] Patent document 1: Japanese Patent No. 3446053

[0012] Patent document 2: Japanese Patent No. 4088768

[0013] Patent document 3: Japanese Patent No. 4804023

[0014] Patent document 4: Japanese Patent Application Publication No. 2015-71730

[0015] Patent document 5: International Publication No. 2020 / 040309 SUMMARY

[0016] PROBLEMS TO BE SOLVED BY THE INVENTION

[0017] However, aluminum nitride powder or silicon dioxide-coated aluminum nitride powder having moisture resistance has problems in compatibility with an organic silicon resin, and reduction of viscosity of an organic silicon monomer slurry. Particularly, when attempting to incorporate aluminum nitride powder at a high filling rate, it is necessary to further improve the compatibility.

[0018] In particular, in the patent document 5 in which it is possible to maintain high thermal conductivity characteristics and achieve excellent moisture resistance, it is necessary to further reduce the slurry viscosity.

[0019] Further, with respect to boron nitride, since primary particles thereof are plate-like, the slurry viscosity significantly increases at a particularly high filling rate, and in silane coupling agent treatment based on a general process, sufficient slurry viscosity reduction effect is not obtained. That is, for a heat dissipation filler, it is evaluated that the true value is the product of two characteristics that it is possible to highly fill in a resin to what extent while securing the thermal characteristics and moldability that the powder itself has. Therefore, the slurry viscosity reduction effect is a characteristic as important as the thermal characteristics.

[0020] The present application has been achieved in view of such circumstances, and aims to provide a method for producing a nitride filler coated with a silanol group-containing organosilicon compound, and a method for producing a silica-coated nitride filler coated with a silanol group-containing organosilicon compound, which can control the reduction in viscosity of a slurry obtained by mixing with a resin monomer.

[0021] Means for solving the problem

[0022] The present inventors have conducted intensive studies, and as a result, have found that the above problems can be solved by using a specific organosilicon compound and a specific alkaline substance, and coating the surface of a nitride filler or a silica-coated nitride filler with them by a specific method, thereby completing the present application. That is, the present application has the following configuration.

[0023] [1] A method for producing a nitride filler coated with a silanol group-containing organosilicon compound, the nitride filler coated with a silanol group-containing organosilicon compound having a nitride filler, and a silanol group-containing organosilicon compound coating film coating the surface of the nitride filler and having a silanol group on the surface, the method comprising: a first A step of covering the surface of the nitride filler with an organosilicon compound having a structure represented by the following general formula (1) to obtain a nitride filler coated with an organosilicon compound covered with the organosilicon compound, and a second A step of treating the surface of the nitride filler coated with an organosilicon compound with an alkaline substance to obtain a nitride filler coated with an organosilicon compound having a silanol group on the surface; or comprising: a first P step of coexisting an organosilicon compound having a structure represented by the following general formula (1) and an alkaline substance in the same atmosphere, and treating the organosilicon compound and the alkaline substance to cover the surface of the nitride filler to obtain a nitride filler coated with an organosilicon compound having a silanol group on the surface;

[0024] In formula (1), R is an alkyl group having 1 to 4 carbon atoms.

[0025] [2] The method for producing a nitride filler coated with a silanol group-containing organosilicon compound according to the above [1], in the second A step, the alkaline substance is aqueous ammonia, and the treatment is performed by immersion in the aqueous ammonia.

[0026] [3] The method for producing a nitride filler coated with a silanol group-containing organosilicon compound according to the above [1], in the second A step, the alkaline substance is aqueous ammonia, and the treatment is performed by a chemical vapor deposition (CVD) method.

[0027] [4] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to any one of the above [1] to [3], wherein, in the first P step, the basic substance is aqueous ammonia, and the treatment is performed by a chemical vapor deposition (CVD) method simultaneously with the silanol group-containing organosilicon compound.

[0028] [5] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to any one of the above [1] to [4], wherein the nitride filler is aluminum nitride particles or boron nitride particles.

[0029] [6] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to the above [5], wherein the cumulative volume 50% particle diameter (D50) of the aluminum nitride particles is 0.1 μm or more and 200 μm or less.

[0030] [7] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to any one of the above [1] to [6], wherein the surface treatment agent is attached to the surface of the silanol group-containing organosilicon compound-coated nitride filler by reaction or interaction.

[0031] [8] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to the above [7], wherein the surface treatment agent is a silane coupling agent.

[0032] [9] A silanol group-containing organosilicon compound-coated nitride filler having a nitride filler, and a silanol group-containing organosilicon compound film covering the surface of the nitride filler, and the silanol group being present on the surface at an average surface density of 0.5 to 2.1 per nm 2 .

[0033]

[10] The silanol group-containing organosilicon compound-coated nitride filler according to the above [9], wherein the surface of the silanol group-containing organosilicon compound-coated nitride filler further has a surface treatment agent.

[0034]

[11] The silanol group-containing organosilicon compound-coated nitride filler according to the above

[10] , wherein the surface treatment agent is a silane coupling agent.

[0035]

[12] A method for producing a silanol group-containing organosilicon compound-coated silica-coated nitride filler having a silica-coated nitride filler, and a silanol group-containing organosilicon compound film covering the surface of the silica-coated nitride filler and having a silanol group on the surface, the method comprising: a first B process of covering a surface of the silica-coated nitride filler with an organic silicon compound having a structure represented by the following general formula (1) to obtain an organic silicon compound-coated silica-coated nitride filler covered with the organic silicon compound, and a second B process of treating a surface of the organic silicon compound-coated silica-coated nitride filler with a basic substance to obtain an organic silicon compound-coated silica-coated nitride filler having a silanol group on the surface; or comprising: a first Q process of allowing an organic silicon compound having a structure represented by the following general formula (1) and a basic substance to coexist in the same atmosphere, and simultaneously treating the organic silicon compound and the basic substance to cover a surface of the silica-coated nitride filler to obtain an organic silicon compound-coated silica-coated nitride filler having a silanol group on the surface;

[0036] In formula (1), R is an alkyl group having 1 to 4 carbon atoms.

[0037]

[13] The method for producing the organic silicon compound-coated silica-coated nitride filler having a silanol group according to the above-mentioned

[12] , in the second B process, the basic substance is aqueous ammonia, and the treatment is performed by immersion in the aqueous ammonia.

[0038]

[14] The method for producing the organic silicon compound-coated silica-coated nitride filler having a silanol group according to the above-mentioned

[12] , in the second B process, the basic substance is aqueous ammonia, and the treatment is performed by a chemical vapor deposition (CVD) method.

[0039]

[15] The method for producing the organic silicon compound-coated silica-coated nitride filler having a silanol group according to the above-mentioned

[12] , in the first Q process, the basic substance is aqueous ammonia, and the treatment is performed by a chemical vapor deposition (CVD) method simultaneously with the organic silicon compound.

[0040]

[16] The method for producing the organic silicon compound-coated silica-coated nitride filler having a silanol group according to any one of the above-mentioned

[12] to

[15] , wherein the nitride filler is an aluminum nitride particle or a boron nitride particle.

[0041]

[17] The method for producing the organic silicon compound-coated silica-coated nitride filler having a silanol group according to the above-mentioned

[16] , wherein a cumulative volume 50% particle diameter (D50) of the aluminum nitride particle is 0.1 μm or more and 200 μm or less.

[0042]

[18] The method for producing a silanol group-containing organosilicon compound-coated silica-coated nitride filler according to any one of the above

[12] to

[17] , wherein the surface treatment agent is attached to the surface of the silanol group-containing organosilicon compound-coated silica-coated nitride filler by reaction or interaction.

[0043]

[19] The method for producing a silanol group-containing organosilicon compound-coated silica-coated nitride filler according to the above

[18] , wherein the surface treatment agent is a silane coupling agent.

[0044]

[20] A silanol group-containing organosilicon compound-coated silica-coated nitride filler having a silica-coated nitride filler, and a silanol group-containing organosilicon compound coating film covering the surface of the silica-coated nitride filler, and the silanol group is present on the surface at an average surface density of 0.5 to 2.1 groups / nm 2 .

[0045]

[21] The silanol group-containing organosilicon compound-coated silica-coated nitride filler according to the above

[20] , wherein the surface of the silanol group-containing organosilicon compound-coated silica-coated nitride filler further has a surface treatment agent.

[0046]

[22] The silanol group-containing organosilicon compound-coated silica-coated nitride filler according to the above

[21] , wherein the surface treatment agent is a silane coupling agent.

[0047] Effects of the Invention

[0048] According to the present application, it is possible to provide a method for producing a silanol group-containing organosilicon compound-coated silica-coated nitride filler capable of controlling the reduction in viscosity of a slurry obtained by mixing with a resin monomer, and a method for producing a silanol group-containing organosilicon compound-coated silica-coated nitride filler. DETAILED DESCRIPTION

[0049] Hereinafter, the present application will be described in detail.

[0050] Any selected mode or any combination of modes described in the present specification is also included in the present application.

[0051] In the present specification, preferred limitations can be arbitrarily selected, and a combination of preferred limitations with each other can be said to be more preferred.

[0052] In the present specification, the description of "XX to YY" means "XX or more and YY or less".

[0053] In the present specification, for a preferable numerical range (e.g., a range of content amount, etc.), lower limit values and upper limit values described in segments can each be independently combined. For example, according to a description of "preferably 10 to 90, more preferably 30 to 60", a "preferable lower limit value (10)" can be combined with a "more preferable upper limit value (60)" to form "10 to 60".

[0054] In the present specification, the film formation method in the "gas film formation method" and the "gas simultaneous film formation method" involved in the treatment of the basic substance includes a film formation method based on a chemical vapor deposition (CVD) method.

[0055] In the present specification, the "cumulative volume 50% particle diameter (D50)" means a particle diameter at which the cumulative value of the volume becomes 50% with respect to a certain particle size distribution. The D50 is calculated from a particle size distribution based on a laser diffraction scattering method. Specifically, it can be measured by using a laser diffraction / scattering type particle size distribution measuring device (Microtrack (Microtrack MT3300EX2) manufactured by NIKKISO CO., LTD., trade name: Microtrack MT3300EX2), etc.

[0056] <Method for producing silanol group-containing organosilicon compound-coated nitride filler>

[0057] The method for producing a silanol group-containing organosilicon compound-coated nitride filler according to the present application, the silanol group-containing organosilicon compound-coated nitride filler having a nitride filler and a silanol group-containing organosilicon compound coating film that coats the surface of the nitride filler and has a silanol group on the surface, the method comprising: a first A step of covering the surface of the nitride filler with an organosilicon compound having a structure represented by the following general formula (1) to obtain a silanol group-containing organosilicon compound-coated nitride filler covered with the organosilicon compound, and a second A step of treating the surface of the silanol group-containing organosilicon compound-coated nitride filler with a basic substance to obtain a silanol group-containing organosilicon compound-coated nitride filler having a silanol group on the surface; or comprising: a first P step of allowing an organosilicon compound having a structure represented by the following general formula (1) and a basic substance to coexist in the same atmosphere, and simultaneously treating the organosilicon compound and the basic substance to cover the surface of the nitride filler, to obtain a silanol group-containing organosilicon compound-coated nitride filler having a silanol group on the surface;

[0058] In formula (1), R is an alkyl group having 1 to 4 carbon atoms.

[0059] (First A step)

[0060] This step is a step of covering the surface of the nitride filler with the organosilicon compound containing the structure represented by the above general formula (1) to obtain the nitride filler covered with the organosilicon compound.

[0061] < Nitride filler >

[0062] In the production method of the nitride filler coated with the organosilicon compound having a silanol group of the present application, as the nitride filler used as a raw material, aluminum nitride, boron nitride, silicon nitride, and the like can be exemplified.

[0063] Among them, from the viewpoint of high thermal conductivity as a filler material of a resin composition, aluminum nitride, boron nitride is preferred.

[0064] (Aluminum nitride particles)

[0065] In the production method of the nitride filler coated with the organosilicon compound having a silanol group of the present application, the aluminum nitride particles used as a raw material can use known aluminum nitride particles such as a commercially available product.

[0066] The production method of the aluminum nitride particles is not particularly limited, and for example, there are a direct nitriding method of directly reacting aluminum metal powder with nitrogen or ammonia, a reduction nitriding method of simultaneously performing a nitriding reaction by heating aluminum oxide while performing carbon reduction of the aluminum oxide under a nitrogen or ammonia atmosphere, and the like.

[0067] In addition, as the aluminum nitride particles, particles in which an agglomerate of aluminum nitride particles is made into a granular shape by sintering can be used, and for example, sintered particles using a high-purity aluminum nitride particle as a raw material can be preferably used.

[0068] Here, the high-purity aluminum nitride particle refers to a particle in which the content of oxygen is low and the content of metal impurities is also low. Specifically, for example, a high-purity aluminum nitride particle in which the content of oxygen is 1% by mass or less and the total content of metal impurities (i.e., metal atoms other than aluminum) is 1000 mass ppm or less is preferred because the aluminum nitride particles contained in the organosilicon compound-coated aluminum nitride particles can obtain higher thermal conductivity at this time.

[0069] The aluminum nitride particles can be used alone or in combination.

[0070] Note that the above content of oxygen can be measured using an inorganic analysis device attached with an infrared detector for oxygen detection, or the like. Specifically, the content of oxygen can be measured by using an oxygen-nitrogen-hydrogen analysis device (ONH836: manufactured by LECO K.K.), or the like.

[0071] In addition, the total content of metal atoms other than aluminum can be measured by an ICP (Inductively Coupled Plasma) mass spectrometer or the like. Specifically, the total content of metal atoms other than aluminum can be measured by using an ICP mass spectrometer (ICPMS-2030: Shimadzu Corporation).

[0072] The shape of the aluminum nitride particles used in the present application is not particularly limited, and examples thereof include irregular shapes (chipped shapes), spherical shapes, elliptical shapes, plate shapes, and the like. In addition, in the case where the aluminum nitride particles coated with the organosilicon compound containing a silanol group are dispersed in the resin composition as fillers, as the aluminum nitride particles, only the same kind of aluminum nitride particles (single substance) having the same shape and structure can be used, or a mixture of aluminum nitride particles in which two or more different kinds of aluminum nitride particles having different shapes and structures are mixed in various proportions can be used.

[0073] In the case where the aluminum nitride particles coated with the organosilicon compound containing a silanol group are dispersed in the resin composition as fillers, the greater the volume ratio (filling amount) of the aluminum nitride particles to the resin composition in the aluminum nitride particles coated with the organosilicon compound containing a silanol group, the higher the thermal conductivity of the resin composition. Therefore, the shape of the aluminum nitride particles is preferably a spherical shape that causes less increase in the viscosity of the resin composition due to the addition of the aluminum nitride particles coated with the organosilicon compound containing a silanol group.

[0074] The cumulative volume 50% particle diameter (D50) of the aluminum nitride particles used in the present application is not particularly limited, and is preferably 0.1 μm or more, more preferably 0.3 μm or more and 200.0 μm or less, further preferably 0.4 μm or more and 100.0 μm or less, and particularly preferably 0.5 μm or more and 85.0 μm or less.

[0075] When the D50 of the aluminum nitride particles is within the above range, even in the case where the resin composition containing the aluminum nitride particles coated with the organosilicon compound containing a silanol group is used in a heat dissipation material mounted on a power electronic component, a heat dissipation material having a minimum thickness can be provided, and the surface of the aluminum nitride particles is easily and uniformly coated with a film, and thus the moisture resistance of the aluminum nitride particles is further improved.

[0076] (Boron nitride particles)

[0077] In the production method of the organosilicon compound containing a silanol group-coated nitride filler of the present application, the boron nitride particles used as a raw material can be known boron nitride particles such as commercially available products.

[0078] The method for producing the boron nitride particles is not particularly limited, and for example, there are (a) a method in which boron is directly nitrided using nitrogen, ammonia, or the like, (b) a method in which a boron halide is reacted with ammonia or an ammonium salt, (c) a method in which a boron compound such as boric acid or boron oxide is reduced and nitrided by reacting the boron compound with a nitrogen-containing compound such as melamine at a temperature of about 800°C, (d) a method in which a boron compound and a carbon source are heated to a high temperature of 1600°C or higher in a nitrogen atmosphere to reduce and nitride the boron compound, and the like. Among these, the method of (d) can use low-cost raw materials and is the most preferable method in the production of boron nitride.

[0079] For example, as commercially available products, UHP-1K (manufactured by Resonac, D50: 8.5 μm), UHP-2 (manufactured by Resonac, D50: 10.5 μm), UHP-S2 (manufactured by Resonac, D50: 1.0 μm), and the like can be given.

[0080] <Organic silicon compound for coating>

[0081] In the method for producing a nitride filler coated with a silanol group-containing organosilicon compound according to the present application, the organic silicon compound used as a raw material for forming the film of the silanol group-containing organosilicon compound coating the nitride filler is an organic silicon compound containing a structure represented by the above formula (1). It can be used without particular limitation regardless of whether it is linear, cyclic, or branched. The structure represented by formula (1) is a hydrosiloxane unit in which hydrogen is directly bonded to a silicon atom.

[0082] In the above formula (1), R is an alkyl group having 1 or more and 4 or less carbon atoms, and from the viewpoint of volatilization of the organic silicon compound, it is preferable that R be a methyl group, an ethyl group, a propyl group, a t-butyl group, or the like, and particularly preferably a methyl group. In the method for producing a nitride filler coated with a silanol group-containing organosilicon compound according to the present application, the organic silicon compound used as a raw material is, for example, an oligomer or a polymer containing a structure represented by formula (1).

[0083] As the organic silicon compound, for example, at least one of a compound represented by the following formula (2) and a compound represented by the following formula (3) is preferable.

[0084]

[0085] In formula (2), R1and R2are each independently a hydrogen atom or a methyl group, at least one of R1and R2is a hydrogen atom, and m is an integer of 0 to 10.

[0086]

[0087] In formula (3), n is an integer of 3 to 6.

[0088] In particular, the cyclic hydrosiloxane oligomer of the above formula (3) in which n is 4 is excellent in that a uniform coating film can be formed on the surface of the aluminum nitride particles. The weight average molecular weight of the organosilicon compound containing the structure represented by formula (1) is preferably 100 or more and 2000 or less, more preferably 150 or more and 1000 or less, and further preferably 180 or more and 500 or less. It is presumed that by using the organosilicon compound containing the structure represented by formula (1) having a weight average molecular weight in this range, a thin and uniform coating film is easily formed on the surface of the nitride filler.

[0089] In the present specification, the weight average molecular weight is a polystyrene conversion weight average molecular weight using gel permeation chromatography (GPC), and specifically, can be measured using a combination of a column (Shodex (registered trademark) LF-804: manufactured by Resonac Corporation) and a differential refractive index detector (Shodex (registered trademark) RI-71S: manufactured by Resonac Corporation).

[0090] In the 1A process, the surface of the above nitride filler is coated with the organosilicon compound containing the structure represented by the above formula (1).

[0091] In the 1A process, the method is not particularly limited as long as the surface of the above nitride filler can be coated with the organosilicon compound containing the structure represented by the above formula (1). As the method of the 1A process, a dry mixing method in which a powder mixing device is used, the organosilicon compound is added by spraying or the like while stirring the nitride filler as a raw material, and coating is performed by dry mixing, and the like can be exemplified. As the powder mixing device, a Henschel mixer, a V-shaped mixer of a container rotation type, a double-cone mixer, a ribbon mixer having mixing blades, a screw-type mixer, a closed-type rotary kiln, stirring using a stirring blade of a closed container using a magnetic coupling, and the like can be exemplified. The temperature conditions in this case depend on the boiling point and vapor pressure of the organosilicon compound containing the structure represented by formula (1), and are not particularly limited, and the preferred temperature is in the range of 10°C or more and 200°C or less, more preferably 20°C or more and 150°C or less, and further preferably 40°C or more and 100°C or less.

[0092] Alternatively, as a method for step 1A, a vapor-phase adsorption method can be used, in which the vapor of an organosilicon compound containing the structure represented by formula (1) is deposited or vapor-deposited onto the surface of a stationary nitride filler, either alone or in a mixture with an inert gas such as nitrogen. While the temperature conditions at this time also depend on the boiling point and vapor pressure of the organosilicon compound containing the structure represented by formula (1), a temperature of 10°C or higher and 200°C or lower is preferred, more preferably 20°C or higher and 150°C or lower, and even more preferably 40°C or higher and 100°C or lower. The processing time is preferably 3 to 7 hours, and even more preferably 3.5 to 5 hours. It should be noted that the system can be pressurized or depressurized as needed [sometimes referred to as chemical vapor deposition (CVD)]. As an apparatus that can be used in this case, an apparatus with a closed system and where the gas within the system can be easily replaced is preferred; for example, a CVD apparatus utilizing a glass container or a dryer can be used. When coating with an organosilicon compound without stirring the nitride filler, a longer processing time is required. However, by intermittently placing the processing container on the vibrator, even powders that are in contact with each other and become shielded, or powders that are far from the air layer above, can be processed efficiently by moving their position.

[0093] There is no particular limitation on the amount of organosilicon compound containing the structure represented by formula (1) used in step 1A. In the nitride filler obtained in step 1A and coated with the organosilicon compound containing the structure represented by formula (1), the coating amount of the organosilicon compound containing the structure represented by formula (1) is preferably the specific surface area (m²) determined by the BET method of the nitride filler. 2 / g) calculated per 1m 2 The surface area is in the range of 0.08 mg or more and 20.0 mg or less, more preferably in the range of 0.09 mg or more and 15.0 mg or less, and even more preferably in the range of 1.0 mg or more and 10.0 mg or less.

[0094] It should be noted that the specific surface area (m²) calculated by the BET method for the above-mentioned nitride fillers... 2 / g) calculated per 1m 2 The amount of organosilicon compound coating on the surface area, containing the structure represented by formula (1), can be obtained by dividing the mass difference of the nitride filler before and after coating with the organosilicon compound by the specific surface area (m²) of the nitride filler determined by the BET method. 2 Surface area (m²) calculated from / g) 2 And find it.

[0095] The specific surface area obtained by the BET method can be determined by the nitrogen adsorption BET one-point method using gas flow. As an evaluation device, the Macsorb HM model-1210 manufactured by Mountech can be used.

[0096] (2A step)

[0097] This step is a step of treating the surface of the nitride filler coated with the organosilicon compound obtained in the 1A step with a basic substance to obtain a nitride filler coated with an organosilicon compound having a silanol group on the surface.

[0098] Specifically, it is a step of converting -Si-H groups (active hydrogen groups) to -Si-OH groups (silanol groups) by allowing the surface of the nitride filler coated with the organosilicon compound obtained in the 1A step to act on a basic substance.

[0099] The basic substance is not particularly limited except that a strong alkaline aqueous solution in which a strong base from a weak base to a strong base, from a Bronsted base to a Lewis base remains in a solid form is not used, and ammonia, monoethylamine, diethylamine, triethylamine, 2-ethanolamine, and the like can be cited. From the viewpoint of ease of separation, ammonia is preferred.

[0100] The above treatment uses an immersion method or a vapor deposition method.

[0101] (Immersion method)

[0102] The immersion method is a film formation method in which the nitride filler coated with the organosilicon compound obtained in the 1A step is immersed in an aqueous solution of a basic substance or the like, and thereby the surface of the nitride filler coated with the organosilicon compound is allowed to act on the above-mentioned basic substance to convert -Si-H groups (active hydrogen groups) to -Si-OH groups (silanol groups).

[0103] The basic substance in the 2A step is preferably ammonia, and the treatment is performed by immersion in the aforementioned ammonia.

[0104] In the immersion method, the concentration of the basic substance is not particularly limited, and for example, in the case where ammonia is used as the basic substance, from the viewpoint of reaction speed, it is preferred to be 0.01 N or more and 10 N or less, from the viewpoint of suppressing side reactions of the residual organosilicon compound and reducing the risk of the working environment, it is more preferred to be 0.1 N or more and 5 N or less, and it is further preferred to be 0.5 N or more and 1.5 N or less.

[0105] The amount of ammonia is not particularly limited, and for example, in the case where the particle diameter (D50) of aluminum nitride particles used in the reaction is 30 μm or more and 100 μm or less, it is preferred to treat with ammonia in an amount of one-third or more of the mass of the particles and one-third or less of the mass of the particles. In the case where the above-mentioned particle diameter (D50) is 0.1 μm or more and less than 30 μm, it is preferred to treat with ammonia in an amount of one-half or more of the mass of the particles and twice or less of the mass of the particles.

[0106] There is no particular limitation as long as the particles are entirely immersed in the ammonia water. As the size of the particles becomes smaller, there is a tendency for the surface of the particles to be poorly wetted by the ammonia water immediately after immersion, and therefore, in such cases, it is preferable to add an amount of ethanol equivalent to that of the ammonia water.

[0107] By adding ethanol, the wetting of the surface of the particles by the ammonia water is improved, and therefore, ethanol can be further added while stirring. The reaction can be one of constant stirring or one of sufficient reaction under the condition of intermittent manual mixing and staticity. The container for manual mixing and stirring is not particularly limited, and a polyethylene jar having a volume of about twice the total volume of the contents is preferably used.

[0108] The treatment temperature is preferably 20°C or higher and 60°C or lower, but since the amount of hydrogen produced immediately after treatment is large, it is preferable to start the treatment at 20°C for safety.

[0109] The treatment time is preferably 20 hours or more and 30 hours or less, and further preferably 22 hours or more and 27 hours or less.

[0110] After the treatment of the basic substance is completed, filtration is performed by suction filtration using filter paper. The filtrate is washed thoroughly with distilled water and then washed with ethanol to make it easy to dry. Drying is fast if an acetone wash is performed at the end. By drying the filtrate at 90°C for 2 hours, a silicone compound-containing aluminum nitride particle coated with silanol groups or a silicone compound-containing aluminum nitride particle coated with silica coated with silanol groups can be obtained, for example.

[0111] (Gas phase film formation method)

[0112] The gas phase film formation method refers to a film formation method in which, for the silicone compound-containing nitride filler obtained in the 1st A process, a water solution of a basic substance or the like is subjected to gas phase film formation or the like, whereby the above-mentioned basic substance is caused to act on the surface of the above-mentioned silicone compound-containing nitride filler, and -Si-H groups (active hydrogen groups) are converted to -Si-OH groups (silanol groups).

[0113] It is preferable that the basic substance in the above-mentioned 2nd A process be ammonia water, and the treatment be performed by the gas phase film formation method.

[0114] In the gas phase film formation method, the concentration of the basic substance is not particularly limited, and, for example, in the case where ammonia water is used as the basic substance, it is preferable to be placed in a place where partial exhaust can be performed in a state where an exhaust hole is provided in a gas-tight container. The concentration of the ammonia water is preferably 0.01 N or more and 10.0 N or less, and more preferably 0.10 N or more and 5.0 N or less, and further preferably 0.50 N or more and 1.50 N or less, from the viewpoint of suppressing side reactions of residual silicone compounds and reducing the risk to the work environment.

[0115] In the case of vapor phase film formation, the reaction rate is lower than that of impregnation with ammonia. Therefore, the processing temperature is preferably 20°C or higher and 80°C or lower, more preferably 20°C or higher and 70°C or lower, and even more preferably 30°C or higher and 60°C or lower.

[0116] The processing time for vapor-phase film formation using ammonia is 24 to 48 hours at a processing temperature of 20°C, but this time can be shortened by increasing the processing temperature. For example, at 50°C, sufficient silanol groups can be introduced in 4 to 5 hours.

[0117] (Step 1P)

[0118] This process involves coexisting an organosilicon compound containing the structure represented by the above general formula (1) and the above alkaline substance in the same atmosphere, and simultaneously processing the organosilicon compound and the above alkaline substance to obtain an organosilicon compound-coated nitride filler with a nitride filler surface having silanol groups on the surface.

[0119] The above treatment uses a gas-phase simultaneous film formation method.

[0120] (Gas-on film formation method)

[0121] The simultaneous atmospheric film formation method refers to the method of coexisting the above-mentioned organosilicon compound and the above-mentioned alkaline substance in the same atmosphere, and simultaneously treating the organosilicon compound containing the structure represented by the above general formula (1) and the above-mentioned alkaline substance to convert the -Si-H group (active hydrogen group) of the organosilicon compound on the surface of the nitride filler into the -Si-OH group (silanol group).

[0122] In the aforementioned first P step, considering the use of ammonia water, a volatile alkaline substance, to replenish the moisture indispensable in the reaction, it is preferable that the alkaline substance in the first P step is ammonia water, and the treatment is carried out by gas-phase simultaneous film formation method.

[0123] In the gas-phase simultaneous film formation method, the concentration of the alkaline substance is not particularly limited. For example, when using ammonia as the alkaline substance, it is preferable to place the container in an airtight location with an exhaust vent, where local ventilation is possible. The concentration of ammonia is preferably 0.01N to 10.0N, and more preferably 0.10N to 5.0N, and even more preferably 0.50N to 1.50N, considering the suppression of side reactions of residual organosilicon compounds and the reduction of operational environmental risks.

[0124] In the case of the gas phase simultaneous film formation method, the treatment temperature is preferably 40°C or higher and 65°C or lower, more preferably 45°C or higher and 65°C or lower, and further preferably 50°C or higher and 65°C or lower, although it also depends on the boiling point and vapor pressure of the organosilicon compound containing the structure represented by formula (1).

[0125] The treatment time depends on the treatment temperature, and the preferred treatment is 3 hours or longer and 12 hours or shorter, more preferably 4 hours or longer and 10 hours or shorter, and further preferably 5 hours or longer and 7 hours or shorter. If the ranges of these concentrations and temperatures are deviated, the reaction time becomes too long, or the reaction becomes too violent, and thus is not preferred.

[0126] After the gas phase simultaneous film formation method is finished, it is preferred to dry at 90°C for 2 hours.

[0127] <Method for producing silica-coated nitride filler particles coated with organosilicon compound having silanol group>

[0128] The method for producing silica-coated nitride filler particles coated with organosilicon compound having silanol group according to the present application, the silica-coated nitride filler particles coated with organosilicon compound having silanol group having a silica-coated nitride filler, and a coating film of organosilicon compound covering the surface of the silica-coated nitride filler and having a silanol group on the surface, the production method comprising: a first B step of covering the surface of the silica-coated nitride filler with an organosilicon compound containing a structure represented by the following general formula (1) to obtain silica-coated nitride filler particles coated with organosilicon compound covered with the organosilicon compound, and a second B step of treating the surface of the silica-coated nitride filler particles coated with organosilicon compound with an alkaline substance to obtain silica-coated nitride filler particles coated with organosilicon compound having a silanol group on the surface; or comprising: a first Q step of allowing an organosilicon compound containing a structure represented by the following general formula (1) and an alkaline substance to coexist in the same atmosphere, and simultaneously treating the organosilicon compound and the alkaline substance to cover the surface of the silica-coated nitride filler to obtain silica-coated nitride filler particles coated with organosilicon compound having a silanol group on the surface;

[0129] In formula (1), R is an alkyl group having 1 to 4 carbon atoms.

[0130] (First B step)

[0131] This step is a step of coating the surface of a silica-coated nitride filler with an organic silicon compound having a structure represented by the above formula (1) to obtain the silica-coated nitride filler coated with the organic silicon compound.

[0132] (Silica-coated aluminum nitride particles)

[0133] In the production method of the silica-coated nitride filler coated with the silanol group-containing organic silicon compound of the present application, the silica-coated aluminum nitride particles used as a raw material can use the above-described aluminum nitride, and can be produced using, for example, the method described in International Publication No. 2020 / 040309, paragraphs 0040 to 0061.

[0134] (Silica-coated boron nitride particles)

[0135] In the production method of the silica-coated nitride filler coated with the silanol group-containing organic silicon compound of the present application, the silica-coated boron nitride particles used as a raw material can use the above-described boron nitride, and can be produced using, for example, the method described in International Publication No. 2020 / 040309, paragraphs 0040 to 0061.

[0136] <Organic silicon compound for coating>

[0137] In the production method of the silica-coated nitride filler coated with the silanol group-containing organic silicon compound of the present application, the organic silicon compound used as a raw material for forming the silanol group-containing organic silicon compound film of the silica-coated nitride filler particle is an organic silicon compound containing a structure represented by the above formula (1). It can be used without particular limitation regardless of the form of a straight chain, a ring, or a branched chain. The structure represented by formula (1) is a hydrosiloxane unit in which hydrogen is directly bonded to a silicon atom.

[0138] In the above formula (1), as R which is an alkyl group having 1 or more and 4 or less carbon atoms, from the viewpoint of volatilization of the organic silicon compound, a methyl group, an ethyl group, a propyl group, a t-butyl group, or the like is preferred, and a methyl group is particularly preferred. In the production method of the silica-coated nitride filler coated with the silanol group-containing organic silicon compound of the present application, the organic silicon compound used as a raw material is, for example, an oligomer or a polymer containing a structure represented by formula (1).

[0139] As the organic silicon compound, for example, at least one of a compound represented by the following formula (2) and a compound represented by the following formula (3) is preferred.

[0140]

[0141] In formula (2), R1and R2are each independently a hydrogen atom or a methyl group, at least one of R1and R2is a hydrogen atom, and m is an integer of 0 to 10.

[0142]

[0143] In formula (3), n is an integer of 3 to 6.

[0144] The cyclic hydrosiloxane oligomer of formula (3) in which n is 4 is particularly excellent in that it can form a uniform coating film on the surface of aluminum nitride particles. The weight average molecular weight of the organosilicon compound having the structure represented by formula (1) is preferably 100 or more and 2000 or less, more preferably 150 or more and 1000 or less, and further preferably 180 or more and 500 or less. It is presumed that by using an organosilicon compound having the structure represented by formula (1) having a weight average molecular weight in this range, a thin and uniform coating film is easily formed on the surface of the silica-coated nitride filler particles. Note that in formula (2), m is preferably 1.

[0145] In the 1B process, the surface of the silica-coated nitride filler is coated with the organosilicon compound having the structure represented by formula (1).

[0146] In the 1B process, the method is not particularly limited as long as the surface of the silica-coated nitride filler can be coated with the organosilicon compound having the structure represented by formula (1). As the method of the 1B process, a dry mixing method in which a powder mixing device is used, the silica-coated nitride filler as a raw material is stirred, and the organosilicon compound is added by spraying or the like, thereby performing dry mixing, and the like can be given. As the powder mixing device, for example, a Henschel mixer, a V-type mixer of a container rotation type, a double-cone mixer, a ribbon mixer having mixing blades, a screw-type mixer, a closed-type rotary kiln, stirring using a stirring blade in a closed container using a magnetic coupling, and the like can be given. The temperature conditions in this case depend on the boiling point and vapor pressure of the organosilicon compound having the structure represented by formula (1) and are not particularly limited, and the preferred temperature is in the range of 10°C or more and 200°C or less, more preferably 20°C or more and 150°C or less, and further preferably 40°C or more and 100°C or less.

[0147] Alternatively, as a method for step 1B, a vapor-phase adsorption method can be used, in which the vapor of an organosilicon compound containing the structure represented by formula (1) is deposited or vapor-deposited onto the surface of a stationary silica-coated nitride filler, either alone or in a mixture with an inert gas such as nitrogen. While the temperature conditions at this time also depend on the boiling point and vapor pressure of the organosilicon compound containing the structure represented by formula (1), a temperature of 10°C or higher and 200°C or lower is preferred, more preferably 20°C or higher and 150°C or lower, and even more preferably 40°C or higher and 100°C or lower. The processing time is preferably 3 to 7 hours, and even more preferably 3.5 to 5 hours. It should be noted that, as needed, the system can be pressurized or depressurized [sometimes referred to as chemical vapor deposition (CVD)]. As an apparatus that can be used in this case, an apparatus that is a closed system and allows for easy replacement of the gas within the system is preferred; for example, a glass container, a dryer, or a CVD apparatus can be used. Coating with an organosilicon compound without stirring the silica-coated nitride filler requires a longer processing time.

[0148] However, by intermittently placing the processing container on the vibrator, even powders that are in contact with each other and thus become shielded, or powders that are far from the air layer above, can be processed efficiently by moving the container.

[0149] There is no particular limitation on the amount of organosilicon compound containing the structure represented by formula (1) used in step 1B. In the silica-coated nitride filler obtained in step 1B and coated with the organosilicon compound containing the structure represented by formula (1), the coating amount of the organosilicon compound containing the structure represented by formula (1) is preferably determined by the specific surface area (m²) of the silica-coated nitride filler by the BET method. 2 / g) calculated per 1m 2 The surface area is in the range of 0.08 mg or more and 20.0 mg or less, more preferably 0.09 mg or more and 15.0 mg or less, and even more preferably 1.0 mg or more and 10.0 mg or less. If the coating amount is too large, the thermal conductivity decreases; conversely, if the coating amount is too small, the moisture resistance becomes insufficient.

[0150] It should be noted that the specific surface area (m²) calculated by the BET method for silica-coated nitride fillers mentioned above is... 2 / g) calculated per 1m 2 The coating amount of the organosilicon compound containing the structure represented by formula (1) on the surface area can be obtained by dividing the mass difference of the silica-coated nitride filler before and after coating with the organosilicon compound by the specific surface area (m²) calculated by the BET method of the silica-coated nitride filler. 2 Surface area (m²) calculated from / g) 2 To find the answer, we need to use the given information.

[0151] The specific surface area determined by the BET method can be measured by nitrogen adsorption BET one-point method using a gas flow method. As an evaluation device, Macsorb HM model-1210 manufactured by Mountech Corporation can be used.

[0152] (2B process)

[0153] This process is a process of treating the surface of the silicone compound-coated silica-coated nitride filler obtained in the 1B process with a basic substance to obtain a silicone compound-coated silica-coated nitride filler having a silanol group on the surface.

[0154] Specifically, it is a process of converting -Si-H groups (active hydrogen groups) to -Si-OH groups (silanol groups) by allowing the surface of the silicone compound-coated silica-coated nitride filler obtained in the 1B process to act on a basic substance.

[0155] As the basic substance, the same substance as in the 2A process can be used, and the preferred basic substance and the like are also the same.

[0156] The above treatment is performed using the immersion method or the vapor deposition method as in the above 2A process.

[0157] (Immersion method)

[0158] The immersion method is a film formation method in which the silicone compound-coated silica-coated nitride filler obtained in the 1B process is immersed in an aqueous solution of a basic substance or the like, the above basic substance is allowed to act on the surface of the above silicone compound-coated silica-coated nitride filler, and -Si-H groups (active hydrogen groups) are converted to -Si-OH groups (silanol groups) as represented by the following formula (Z).

[0159]

[0160] Preferably, the basic substance in the process 2B is aqueous ammonia, and the treatment is performed by immersion in aqueous ammonia.

[0161] In the immersion method, the concentration of the basic substance is not particularly limited, and for example, in the case where aqueous ammonia is used as the basic substance, it is preferably 0.01 N or more and 10.0 N or less from the viewpoint of the reaction rate, more preferably 0.10 N or more and 5.0 N or less from the viewpoint of suppressing side reactions of the residual silicone compound and reducing the risk of the working environment, and further preferably 0.50 N or more and 1.50 N or less.

[0162] As for the amount of ammonia water, for example, in the case where the particle diameter (D50) of the silicon dioxide-coated aluminum nitride particles used in the reaction is 30 μm or more and 100 μm or less, it is preferable to treat with ammonia water in an amount of one-third or more of the mass of the particles and one mass or less of the mass of the particles. In the case where the above particle diameter (D50) is 0.1 μm or more and less than 30 μm, it is preferable to treat with ammonia water in an amount of one-half or more of the mass of the particles and twice the mass of the particles or less.

[0163] There is no particular limitation as long as about one-third of the surface area of the particles is dipped in the ammonia water. As the size of the particles becomes smaller, there is a tendency that the surface of the particles is not well wetted with the ammonia water immediately after dipping, and therefore, in such a case, it is preferable to add ethanol in an amount equivalent to the ammonia water. By adding ethanol, the wetting of the surface of the particles with the ammonia water is improved, and therefore, it is sufficient to further add ethanol while stirring. The reaction can be performed while stirring continuously or under a condition where the manual mixing is intermittent and the container is at rest. There is no particular limitation to the container for manual mixing and stirring, and it is preferable to use a polyethylene jar having a volume of about twice the total volume of the contents.

[0164] The treatment temperature is preferably 20°C or more and 60°C or less, but since the amount of hydrogen generated immediately after the treatment is large, it is preferable to start the treatment at 20°C or more for safety.

[0165] The treatment time is preferably 20 hours or more and 30 hours or less, and further preferably 22 hours or more and 27 hours or less.

[0166] After the treatment of the basic substance is completed, the filter is filtered by suction filtration using filter paper. The filtrate is washed with distilled water sufficiently and then washed with ethanol to make it easy to dry. Drying is fast when the final acetone washing is performed. By drying the filtrate at 90°C for 2 hours, a silicon compound-coated silicon dioxide-coated aluminum nitride particle having a silanol group on the surface, for example, can be obtained.

[0167] (Gas phase film formation method)

[0168] The gas phase film formation method is a film formation method in which a water solution of a basic substance or the like is subjected to gas phase film formation or the like, and the above basic substance is allowed to act on the surface of the above silicon compound-coated silicon dioxide-coated nitride filler, as represented by the above formula (Z), to convert -Si-H groups (active hydrogen groups) into -Si-OH groups (silanol groups).

[0169] It is preferable that the above basic substance in the above 2B process be ammonia water, and the above treatment be performed by the gas phase film formation method.

[0170] In the vapor deposition method, the concentration of the basic substance is not particularly limited, for example, in the case where aqueous ammonia is used as the basic substance, it is preferable to place it in a state where a gas exhaust hole is provided in a gas-tight container in a place where partial exhaust is possible. The concentration of the aqueous ammonia is preferably 0.01 N or more and 10 N or less, more preferably 0.1 N or more and 5 N or less, and further preferably 0.5 N or more and 1.5 N or less, from the viewpoint of suppressing side reactions of the residual organosilicon compound and reducing the risk to the working environment.

[0171] In the case of the vapor deposition method, the reaction rate is low compared to the immersion method using aqueous ammonia, and thus the treatment temperature is preferably 20°C or more and 80°C or less, more preferably 20°C or more and 70°C or less, and further preferably 30°C or more and 60°C or less.

[0172] The treatment time in the vapor deposition method using aqueous ammonia is about 24 to 48 hours when the treatment temperature is 20°C, but the treatment time can be shortened by increasing the treatment temperature. For example, when the treatment is performed at 50°C, it is possible to introduce sufficient silanol groups in about 4 to 5 hours.

[0173] After the alkali treatment, it is preferable to dry at 90°C for 2 hours.

[0174] (First Q Step)

[0175] This step is a step of coexisting the organosilicon compound containing the structure represented by the above general formula (1) and the above basic substance in the same atmosphere, simultaneously treating the above organosilicon compound and the above basic substance, and obtaining a silica-coated nitride filler coated with an organosilicon compound having a silanol group on the surface of the silica-coated nitride filler.

[0176] The above treatment uses a vapor simultaneous deposition method.

[0177] (Vapor Simultaneous Deposition Method)

[0178] The vapor simultaneous deposition method is a method of coexisting the above organosilicon compound and the above basic substance in the same atmosphere, simultaneously treating the organosilicon compound containing the structure represented by the above general formula (1) and the above basic substance, and depositing the organosilicon compound by converting the -Si-H group (active hydrogen group) of the organosilicon compound to the -Si-OH group (silanol group) on the surface of the silica-coated nitride filler.

[0179] In the first Q step, the basic substance in the first Q step is preferably aqueous ammonia from the viewpoint of supplementing the moisture indispensable to the reaction by using aqueous ammonia as a volatile basic substance, and the treatment is performed by a vapor simultaneous deposition method.

[0180] In the gas-phase simultaneous film formation method, the concentration of the alkaline substance is not particularly limited. For example, when using ammonia as the alkaline substance, it is preferable to place the container in an airtight location with an exhaust vent, where local ventilation is possible. The concentration of ammonia is preferably 0.01N to 10.0N, and more preferably 0.10N to 5.0N, and even more preferably 0.50N to 1.50N, considering the suppression of side reactions of residual organosilicon compounds and the reduction of operational environmental risks.

[0181] In the case of simultaneous vapor deposition, although it also depends on the boiling point and vapor pressure of the organosilicon compound containing the structure represented by formula (1), the processing temperature is preferably 40°C or higher and 65°C or lower, more preferably 45°C or higher and 65°C or lower, and even more preferably 50°C or higher and 65°C or lower.

[0182] The processing time depends on the processing temperature. The preferred processing time is 3 hours or more and 12 hours or less, more preferably 4 hours or more and 10 hours or less, and even more preferably 5 hours or more and 7 hours or less.

[0183] After the gas-phase film formation method is completed, it is preferable to dry at 90°C for 2 hours.

[0184] (Surface treatment agent)

[0185] The preferred surface treatment agent adheres to the surface of the silanol-based organosilicon compound-coated nitride filler or the silica-based organosilicon compound-coated nitride filler obtained by the present invention through reaction or interaction.

[0186] As a surface treatment agent, silane coupling agents, compounds having one or more groups selected from amino, carboxyl, and epoxy groups, or modified silicone oils can be used. Among these, silane coupling agents are preferred.

[0187] As a silane coupling agent, any known compound can be used as long as it has a hydrolyzable substituent such as a halogen atom or alkoxy group on the silicon atom. Preferred compounds include, for example, vinyltrichlorosilane, vinyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-epoxypropoxypropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-decyltrimethoxysilane (manufactured by Shin-Etsu Silicon Co., Ltd., KBM-3103), n-dodecyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and hexamethyldisilazane (manufactured by Shin-Etsu Silicon Co., Ltd., SZ-31). These silane coupling agents can be used alone or in combination.

[0188] As the compound having one or more of an amino group, a carboxyl group, an epoxy group, a compound that is easily adsorbed to the surface of each nitride filler or reacts with the surface of each nitride filler by the action of these groups is preferable, and a publicly known compound can be used.

[0189] For example, 1,2-epoxyhexane, 1,2-epoxydodecane, n-hexylamine, n-dodecylamine, p-n-hexylaniline, n-hexylcarboxylic acid, n-dodecylcarboxylic acid, p-n-hexylbenzoic acid, and the like are preferable.

[0190] As the modified silicone oil, KF-105, KF-101, KF-102, X-22-173DX, KF-393, KF-864, KF-8012, KF-857, X-22-3667, X-22-162A, X-22-3701E (all of which are manufactured by Shin-Etsu Chemical Co., Ltd.), TSF4700, TSF4701, TSF4702, TSF4703, TSF4730, TSF4770, TSE3070 (all of which are manufactured by Momentive), SF8417, BY16-828, BY16-849, BY16-892, BY16-853, BY16-837, SF8411, BY16-875, BY16-855, SF8421, SF8418, BY16-874 (all of which are manufactured by DuPont-Toray Speciality Materials Co., Ltd.), and the like are preferable, and these substances can be used alone or in a plurality of kinds. As the production method of coating these compounds on the nitride filler coated with the organosilicon compound having a silanol group or the nitride filler coated with the silica coated with the organosilicon compound having a silanol group, there is no particular limitation, and a publicly known method can be used.

[0191] For example, there is a direct method in which the filler is surface-treated in advance. The direct method has a dry method, an immersion method, and a bulk method. The dry method is a method in which a reagent is added dropwise to the filler and stirred and mixed, and the solvent in which the reagent is diluted, a reaction byproduct is evaporated and dried as appropriate. The immersion method is a method in which the filler is buried in a solution of a surface treatment agent, stirred and mixed, filtered, and the solvent, a reaction byproduct is evaporated and dried. The bulk method is a method in which the surface treatment agent is added at the time of kneading with a polymer.

[0192] As the device at the time of performing the treatment, a Henschel mixer, a Nauta mixer, and the like are preferable, as the device at the time of performing the mixing, a kneader, a planetary mixer, and the like are preferable, and drying has a drying by an oven, natural drying, and the like, and a publicly known method can be used.

[0193] As the device at the time of performing the treatment, a Henschel mixer, a Nauta mixer, and the like are preferable, as the device at the time of performing the mixing, a kneader, a planetary mixer, and the like are preferable, and drying has a drying by an oven, natural drying, and the like, and a publicly known method can be used.

[0194] The amount of the silane coupling agent coated on the nitride filler coated with the organosilicon compound having a silanol group or the silica-coated nitride filler coated with the organosilicon compound having a silanol group is preferably 0.05 to 10.0% by mass relative to the nitride filler or the silica-coated nitride filler. By setting it to 0.05% by mass or more, the coating effect is easily obtained. By setting it to 10.0% by mass or less, the content of unreacted silane coupling agent or the like is reduced, and the case where impurities remain is less.

[0195] The feeding ratio of the silane coupling agent is preferably 0.5 to 180 times, more preferably 1.0 to 120 times, and further preferably 2.0 to 100 times, from the viewpoint of the effect of reducing the flow viscosity of the slurry and preventing the aggregation of the filler due to unreacted silane coupling agent.

[0196] Note that the feeding ratio of the silane coupling agent means the feeding ratio when the amount of the silane coupling agent calculated from the BET specific surface area of the nitride filler and the minimum coating area of the silane coupling agent is taken as 1 time. The minimum coating area of the silane coupling agent is calculated based on the molecular weight of the silane coupling agent by the following formula.

[0197] Minimum coating area [m 2 / g] = 6.02 x 10 23 x 13 x 10 -20 / molecular weight of silane coupling agent

[0198] (Method for producing resin composition)

[0199] A resin composition can be produced using the nitride filler coated with the organosilicon compound having a silanol group after surface treatment of the nitride filler coated with the organosilicon compound having a silanol group obtained in the production method of the present application, or the silica-coated nitride filler coated with the organosilicon compound having a silanol group after surface treatment of the silica-coated nitride filler coated with the organosilicon compound having a silanol group.

[0200] That is, the method for producing a resin composition in the present application can have a production step of the nitride filler coated with the organosilicon compound having a silanol group by the above-mentioned method for producing the nitride filler coated with the organosilicon compound having a silanol group, a production step of the nitride filler coated with the organosilicon compound having a silanol group after surface treatment, a mixing step of mixing the nitride filler coated with the organosilicon compound having a silanol group after surface treatment with a resin.

[0201] Alternatively, the method for producing the resin composition of the present application can have: a method for producing a silanol group-containing silicone compound-coated nitride filler coated with silica, a method for producing a surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica, a production step of producing a silanol group-containing silicone compound-coated nitride filler coated with silica; a production step of producing a surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica; and a mixing step of mixing the surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica with a resin.

[0202] In the mixing step, the surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica produced by the method for producing a surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica is mixed with a resin.

[0203] Alternatively, in the mixing step, the surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica produced by the method for producing a surface-treated silanol group-containing silicone compound-coated nitride filler coated with silica is mixed with a resin.

[0204] As the resin to be mixed in the mixing step, there is no particular limitation, and from the viewpoint of heat resistance, a thermosetting resin, a thermoplastic resin, or a mixture of a thermosetting resin and a thermoplastic resin can be exemplified. From the viewpoint of controlling the viscosity of the slurry, a thermosetting resin having a functional group capable of reacting with an active hydrogen group (for example, a vinyl group, an allyl group, or the like), or a thermosetting resin into which such a group is introduced is preferred. As such a thermosetting resin, for example, a silicone resin such as polydimethylsiloxane, an epoxy resin, a phenol resin, a bismaleimide resin, a cyanate ester resin, a polyurethane resin, a (meth)acrylic resin, a vinyl ester resin, an unsaturated polyester resin, a polyvinyl acetal resin, or the like can be exemplified, and these can be used alone or in combination with two or more kinds. Furthermore, a mixture in which the above-mentioned curing agent and curing accelerator are added to the thermosetting resin can also be used. In particular, from the viewpoint of good heat resistance, adhesiveness, and electrical properties after curing, an epoxy resin is preferred, and in applications where soft adhesion is valued, a silicone resin is preferred.

[0205] The silicone resin is an addition reaction-curable silicone resin, a condensation reaction-curable silicone resin, an organic peroxide-curable silicone resin, or the like, and can be used alone or in combination with two or more kinds of silicone resins having different viscosities. In particular, when the obtained resin composition is used in applications where soft adhesion is valued, as the silicone resin, for example, an addition reaction-curable liquid silicone resin that does not generate by-products that can become a cause of bubbles or the like can be mentioned. By reacting an organopolysiloxane having an alkenyl group as a base polymer with an organopolysiloxane having an Si-H group as a crosslinking agent in the presence of a curing catalyst at ordinary temperature or with heating, a silicone resin cured product can be obtained. Note that specific examples of the organopolysiloxane as the base polymer include organopolysiloxanes having a vinyl group, an allyl group, a propenyl group, a hexenyl group, or the like as the alkenyl group. In particular, a vinyl group is preferable for the organopolysiloxane. In addition, as the curing catalyst, for example, a platinum metal-based curing catalyst can be used, and the amount of addition can also be adjusted for use in order to achieve the hardness of the resin cured product as a target.

[0206] As the epoxy resin, a difunctional glycidyl ether type epoxy resin such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a hydrogenated bisphenol A type epoxy resin, a biphenyl type epoxy resin, a glycidyl ester type epoxy resin such as hexahydrophthalic acid glycidyl ester, a dimer acid glycidyl ester, a linear aliphatic epoxy resin such as an epoxidized polybutadiene, an epoxidized soybean oil, a heterocyclic type epoxy resin such as isocyanuric acid triglycidyl ester, a glycidyl amine type epoxy resin such as N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-1,3-benzenedi(methylamine), 4-(glycidyloxy)-N,N-diglycidylaniline, 3-(glycidyloxy)-N,N-diglycidylaniline, a multifunctional glycidyl ether type epoxy resin such as a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a biphenyl aralkyl type epoxy resin, a naphthalene aralkyl type epoxy resin, a 4-functional naphthalene type epoxy resin, a triphenylmethane type epoxy resin, or the like can be mentioned. The above-described epoxy resins can be used alone or in combination with two or more kinds.

[0207] In the case of using the above-mentioned epoxy resin, a curing agent, a curing accelerator can be used in combination. As the curing agent, for example, alicyclic acid anhydride such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride; aliphatic acid anhydride such as dodecenylsuccinic anhydride; aromatic acid anhydride such as phthalic anhydride, trimellitic anhydride; bisphenol such as bisphenol A, bisphenol F, bisphenol S; phenol-formaldehyde resin such as phenol-formaldehyde resin, phenol-aralkyl resin, naphthol-aralkyl resin, phenol-dicyclopentadiene copolymer resin; organic dihydrazide such as dicyandiamide, adipic acid dihydrazide; and as the curing catalyst, for example, amine such as tris(dimethylaminomethyl)phenol, dimethylbenzylamine, 1,8-diazabicyclo(5,4,0)undecene and derivatives thereof; imidazole such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and derivatives thereof can be exemplified. They can be used alone or in combination of two or more.

[0208] In the mixing step, in addition to the above-mentioned silanol group-containing organosilicon compound-coated nitride filler or the above-mentioned silanol group-containing organosilicon compound-coated silica-coated nitride filler, a filler such as alumina, silica, zinc oxide, which is usually used, can be used in combination.

[0209] In the mixing step, the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler and a filler other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler, or the above-mentioned surface-treated silanol group-containing organosilicon compound-coated silica-coated nitride filler and a filler other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated silica-coated nitride filler, can be mixed in an amount to form a desired resin composition.

[0210] The total volume content of the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler and a filler other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler, or the total volume content of the above-mentioned surface-treated silanol group-containing organosilicon compound-coated silica-coated nitride filler and a filler other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated silica-coated nitride filler, in the obtained resin composition is preferably 50% by volume or more and 99% by volume or less, more preferably 60% by volume or more and 97% by volume or less, and further preferably 70% by volume or more and 95% by volume or less, respectively. If the total volume content is 50% by volume or more, good heat dissipation can be achieved, and if it is 99% by volume or less, good workability can be obtained when the resin composition is used.

[0211] In the obtained resin composition, the volume content of the nitride filler coated with the surface-treated silanol group-containing organosilicon compound is preferably 30% by volume or more and 100% by volume or less, more preferably 40% by volume or more and 100% by volume or less, and further preferably 50% by volume or more and 100% by volume or less, of the total volume content of the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler and fillers other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler. When the total volume content is 30% by volume or more, good heat dissipation can be achieved.

[0212] In the obtained resin composition, the volume content of the nitride filler coated with the surface-treated silanol group-containing organosilicon compound is preferably 30% by volume or more and 100% by volume or less, more preferably 40% by volume or more and 100% by volume or less, and further preferably 50% by volume or more and 100% by volume or less, of the total volume content of the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler and fillers other than the above-mentioned surface-treated silanol group-containing organosilicon compound-coated nitride filler. When the total volume content is 30% by volume or more, good heat dissipation can be achieved.

[0213] In the mixing step, a flexible imparting agent such as a silicone, a urethane acrylate, a butyral resin, an acrylic rubber, a diene-based rubber, and a copolymer thereof, a silane-based coupling agent, a titanium-based coupling agent, an inorganic ion capturing agent, a pigment, a dye, a diluent, a solvent, and the like can be further added as needed.

[0214] The mixing method in the mixing step is not particularly limited, and for example, a method in which the surface-treated silanol group-containing organosilicon compound-coated nitride filler or the surface-treated silanol group-containing organosilicon compound-coated silica-coated nitride filler, a resin, and other additives, and the like are mixed, dissolved, and kneaded by using a dispersing-dissolving device such as a grinder, a planetary mixer, a revolution-revolution mixer, a kneader, a roll mill, and the like, alone or in appropriate combination, and heated as needed, thereby obtaining a slurry or the like, can be mentioned.

[0215] In addition, the obtained resin composition can be molded into a sheet shape, and reacted as needed to form a heat dissipation sheet. The above-mentioned resin composition and heat dissipation sheet can be suitably used for bonding applications and the like of semiconductor power devices, power modules, and the like.

[0216] < Nitride filler coated with surface-treated silanol group-containing organosilicon compound >

[0217] The silanol group-containing organosilicon compound-coated nitride filler of the present application is characterized by having a nitride filler, and a silanol group-containing organosilicon compound film coating the surface of the above-mentioned nitride filler and having silanol groups present on the surface at an average surface density of 0.5 to 2.1 groups / nm 2 .

[0218] (Average surface density of silanol groups)

[0219] The average surface density of the silanol groups of the above-mentioned silanol group-containing organosilicon compound-coated nitride filler is 0.5 to 2.1 groups / nm 2 . When less than 0.5 groups / nm 2 , adequate slurry viscosity reduction effects cannot be obtained. In addition, the maximum number of silanol groups that can be introduced is roughly dependent on the type of organosilicon material used in the CVD, but even if the treatment temperature is set to 50°C or higher for the purpose of increasing the reaction rate, or the treatment time is extended, it does not exceed 2.1 groups / nm 2 .

[0220] The average surface density of the silanol groups is preferably 0.6 to 2.1 groups / nm 2 , and further preferably 0.7 to 2.1 groups / nm 2 .

[0221] Note that in order to reduce the average surface density of the silanol groups, it can be arbitrarily controlled by performing a heat treatment in the range of 150°C to 250°C for 2 hours after the CVD treatment of the organosilicon material and before the ammonia treatment. The temperature and time can be freely set according to the cumulative heat amount, and as a guideline, it can be reduced to about two-thirds at 150°C for 2 hours, and to about one-fourth at 200°C for 2 hours, with respect to the average surface density of the silanol groups of 1.3 groups / nm 2 .

[0222] In the present application, the average surface density of the silanol groups of the silanol group-containing organosilicon compound-coated nitride filler can be measured, for example, by the method described in the Examples below.

[0223] It is preferable that the surface of the above-mentioned silanol group-containing organosilicon compound-coated nitride filler further have a surface treatment agent.

[0224] As the surface treatment agent, a silane coupling agent, a compound having one or more of an amino group, a carboxyl group, an epoxy group, or a modified silicone oil, etc. can be used. Among these, the surface treatment agent is preferably a silane coupling agent from the viewpoint of the reactivity with the silanol groups on the surface of the silanol group-containing organosilicon compound-coated nitride filler.

[0225] The amount of the silanol group-containing organosilicon compound coating the nitride filler is preferably 0.05 to 5.0 mass% relative to the silanol group-containing organosilicon compound-coated nitride filler. By setting it to 0.05 mass% or more, the coating effect is easily obtained. By setting it to 5.0 mass% or less, the amount of unreacted silane coupling agent or the like is reduced, and the amount of impurities remaining is reduced.

[0226] <silicon dioxide-coated nitride filler coated with silanol group-containing organosilicon compound>

[0227] The silicon dioxide-coated nitride filler coated with a silanol group-containing organosilicon compound according to the present application is characterized by comprising a silicon dioxide-coated nitride filler, and a silanol group-containing organosilicon compound film coating the surface of the above-mentioned silicon dioxide-coated nitride filler and having silanol groups present on the surface at an average surface density of 0.5 to 2.1 groups / nm 2 .

[0228] (Average surface density of silanol groups)

[0229] The average surface density of the silanol groups of the above-mentioned silicon dioxide-coated nitride filler coated with a silanol group-containing organosilicon compound is 0.5 to 2.1 groups / nm 2 . When it is less than 0.5 groups / nm 2 , the slurry viscosity reduction effect is not sufficient. In addition, the maximum number of silanol groups that can be introduced is roughly dependent on the type of organosilicon material used in the CVD, but even if the treatment temperature is set to 50°C or more for the purpose of increasing the reaction rate, or the treatment time is extended, it does not exceed 2.1 groups / nm 2 .

[0230] The average surface density of the silanol groups is preferably 0.6 to 2.1 groups / nm 2 , and further preferably 0.7 to 2.1 groups / nm 2 , from the viewpoint of obtaining a sufficient slurry viscosity reduction effect.

[0231] Note that, in order to reduce the average surface density of the silanol groups, it can be arbitrarily controlled by performing heat treatment at 150°C to 250°C for 2 hours after the CVD treatment of the organosilicon material and before the ammonia treatment. The temperature and time can be freely set by the amount of heat received, and as a guideline, from 1.3 groups / nm 2 , it can be reduced to about two-thirds at 150°C for 2 hours, and to about one-fourth at 200°C for 2 hours.

[0232] In the present application, the average surface density of silanol groups of the silanol group-containing organosilicon compound-coated silica-coated nitride filler can be measured, for example, by the method described in the Examples below.

[0233] Preferably, the surface of the above-described silanol group-containing organosilicon compound-coated silica-coated nitride filler is further provided with a surface treatment agent.

[0234] As the surface treatment agent, a silane coupling agent, a compound having one or more of an amino group, a carboxyl group, an epoxy group, or a modified silicone oil, etc. can be used. Among these, the surface treatment agent is preferably a silane coupling agent from the viewpoint of the reactivity with the silanol groups on the surface of the silanol group-containing organosilicon compound-coated silica-coated nitride filler.

[0235] The coating amount of the silanol group-containing organosilicon compound-coated silica-coated nitride filler with respect to the silanol group-containing organosilicon compound-coated silica-coated nitride filler is preferably 0.05 to 5.0 mass% of a silane coupling agent, etc. By setting it to 0.05 mass% or more, the coating effect is easily obtained. By setting it to 5.0 mass% or less, the content of unreacted silane coupling agent, etc. is reduced, and the case of remaining as an impurity is less.

[0236] Examples

[0237] Next, the present application is specifically described by way of Examples, but the present application is not limited by these Examples at all.

[0238] [Preparation of silica-coated aluminum nitride particles]

[0239] The surface of the aluminum nitride particles A was coated using a vacuum dryer that was made of acrylic resin with a plate thickness of 20 mm, had an internal size of 260 mm x 260 mm x 100 mm, and was divided into two layers by a partition with a through hole.

[0240] First, 200 g of the aluminum nitride particles A (FAN-f80-A1: manufactured by Furukawa Electric Co., Ltd.) having a cumulative volume 50% particle diameter (D50) of 80 μm and a specific surface area of 0.08 m 2 / g obtained by the BET method were uniformly spread on a stainless steel tray and left standing in the upper section of the vacuum dryer.

[0241] Next, 20 g of the organosilicon compound A (2,4,6,8-tetramethylcyclotetrasiloxane (D4H): manufactured by Tokyo Chemical Industry Co., Ltd.) of formula (3) with n = 4 was placed in the lower section of the vacuum dryer. The sample was placed in a 120°C glass petri dish and allowed to stand. Then, a vacuum desiccator was sealed, and CVD treatment was performed at 80°C for 8 hours using an oven. The sample was then transferred to an alumina crucible and heat-treated at 850°C for 6 hours to obtain silica-coated aluminum nitride particles A.

[0242] In the above, aluminum nitride particles A are changed to have a cumulative volumetric 50% particle size (D50) of 1.0 μm and a specific surface area obtained by the BET method of 2.4 m². 2 / g of aluminum nitride particles B (TFZ-N01P: manufactured by Toyo Aluminum Co., Ltd.) were obtained by changing the heat treatment at 850°C for 6 hours to 700°C for 3 hours, and then performing the same operation as above to obtain silica-coated aluminum nitride particles B.

[0243] (Example 1)

[0244] [Preparation (Immersion Method) and Surface Treatment of Silica-Coated Aluminum Nitride Particles with Introduced Silanol Groups]

[0245] At the bottom of the SUS-made 8L pressure vessel, 11.0 g of 2,4,6,8-tetramethylcyclotetrasiloxane (D4H) was placed in a 50 mL glass petri dish. Next, 200 g of the aforementioned silica-coated aluminum nitride particles A were placed in a tray made of aluminum foil. The tray was then placed on a SUS-made raised-bottom slat plate (snoko) on top of an 8L SUS pressure vessel. The lid of the 8L pressure vessel was then placed on top, and the mixture was kept in a sealed oven at 80°C for 10 minutes. After depressurization, the mixture was again subjected to CVD treatment at 80°C for 4.5 hours (D4H concentration: D4H partial pressure 1.30 × 10⁻⁶). 4 Pa (80℃) [CVD1 treatment].

[0246] Next, 200g of 1N-ammonia water was placed in a 1L polyethylene wide-mouth bottle, followed by all the CVD-treated sample described above. The mixture was manually stirred every hour for the first 3 hours, and then allowed to stand at room temperature in a local exhaust system for 24 hours. During the standing period, the bottle was not sealed, allowing the generated hydrogen to leak out through the gaps in the lid. After 24 hours, the mixture was vacuum filtered using coarse filter paper that could maintain particle size. The filtrate was washed twice with distilled water and twice with ethanol, and then dried at 90°C for 2 hours, thus obtaining silica-coated aluminum nitride particles A (impregnation method) with silanol groups introduced into them.

[0247] Next, with respect to 100 parts by mass of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A, 2.4 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Silicone, KBM-3103: decyltrimethoxysilane) was mixed by the dipping method, and the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A were surface-treated (SC1 treatment). Note that the feeding ratio of the silane coupling agent was set to 90. Then, after drying at room temperature for 2 hours, heat treatment was performed at 120°C for 2 hours using a drying machine, and thus a sample of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A surface-treated with the silane coupling agent was obtained.

[0248] The feeding ratio of the silane coupling agent indicates the feeding ratio when the amount of the silane coupling agent calculated from the BET specific surface area of the aluminum nitride particles A and the minimum coating area of the silane coupling agent is taken as 1. The minimum coating area of the silane coupling agent is calculated based on the molecular weight of the silane coupling agent by the following formula.

[0249] Minimum coating area [m 2 / g]=6.02 x 10 23 x 13 x 10 -20 / molecular weight of silane coupling agent

[0250] The CVD treatment conditions in Example 1 and Examples 2 to 11 described below, and Comparative Examples 1 to 11 described below are shown in Table 3, the basic substance treatment conditions are shown in Table 4, and the silane coupling agent treatment conditions are shown in Table 5.

[0251] (Example 2)

[0252] In Example 1, the CVD treatment conditions were set to 80°C for 1 hour, and the D4H concentration was set to a D4H partial pressure of 8.12 x 10 2 Pa (80°C) [CVD2 treatment], and otherwise, the same operations as in Example 1 were performed to obtain a sample of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A surface-treated with the silane coupling agent.

[0253] (Example 3)

[0254] In Example 1, the CVD treatment conditions were set to 80°C for 1 hour, and the D4H concentration was set to a D4H partial pressure of 2.03 x 10 2 Pa (80°C) [CVD3 treatment], and otherwise, the same operations as in Example 1 were performed to obtain a sample of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A surface-treated with the silane coupling agent.

[0255] (Example 4)

[0256] In Example 1, 1N-ammonia 100 ml, ethanol 100 ml were added to a 1L polyethylene wide-mouth bottle, all of the above CVD-treated sample was added, manual stirring was performed every 1 hour for the first 3 hours, and then, the sample was left to stand for 24 hours at room temperature in a partial evacuation apparatus, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the silica-coated aluminum nitride particles A to which a silane coupling agent was surface-treated, which were the silica-coated aluminum nitride particles A to which a silanol group was introduced.

[0257] (Example 5)

[0258] [Preparation of silica-coated aluminum nitride particles to which a silanol group was introduced (vapor deposition method) and surface treatment]

[0259] In the bottom (the lowest section) of a SUS-made 8L pressure-resistant vessel, 2,4,6,8-tetramethylcyclotetrasiloxane (D4H) 11.0 g was placed in a glass-made 50 petri dish. Next, 200 g of the above D4H-treated silica-coated aluminum nitride particles A was placed in an aluminum-foil-made tray, the tray was placed on a SUS-made convex-bottomed grid plate in the upper portion of the SUS-made 8L pressure-resistant vessel, the lid of the 8L pressure-resistant vessel was closed, and the CVD treatment was performed for 4 hours in a closed state in an oven maintained at 80°C after depressurization.

[0260] (D4H concentration: D4H partial pressure 1.30 x 10 4 Pa (80°C)) [CVD4 treatment].

[0261] Next, the D4H-treated silica-coated aluminum nitride particles A placed in the glass-made 50 petri dish were taken out, and 1N-ammonia 20 g was placed in a glass-made 120 petri dish in the bottom (the lowest section) of the 8L pressure-resistant vessel. Next, the D4H-treated silica-coated aluminum nitride particles A placed in the glass-made 50 petri dish were placed again on the glass-made 120 petri dish. In a state where the lid was closed and one of the depressurization holes was opened, the sample was left to stand for 24 hours at room temperature, and the sample was taken out and dried at 90°C for 2 hours, whereby the silica-coated aluminum nitride particles A to which a silanol group was introduced (vapor deposition method) were obtained.

[0262] ​​​​Next, 100 parts by mass of silica-coated aluminum nitride particles A with silanol groups were mixed with 2.4 parts by mass of a silane coupling agent (Shin-Etsu Silicones Co., Ltd., KBM-3103: decyltrimethoxysilane) by impregnation and surface treated (SC1 treatment). It should be noted that the silane coupling agent dosage ratio was set to 90. Then, after drying at room temperature for 2 hours, a heat treatment was performed at 120°C for 2 hours using a dryer, thus obtaining a sample of silica-coated aluminum nitride particles A with silanol groups introduced by surface treatment using a silane coupling agent.

[0263] [Example 6]

[0264] In Example 1, the CVD treatment conditions were set to 80°C for 4 hours [CVD4 treatment], and the silane coupling agent treatment conditions were set to silane coupling agent (Shin-Etsu Silicon Co., Ltd., SZ-31: hexamethyldisilazane) (SC2 treatment) with a silane coupling agent feed ratio of 5. Otherwise, the same operation as in Example 1 was performed to obtain a sample of silica-coated aluminum nitride particles A with silanol groups introduced and surface-treated with silane coupling agent.

[0265] [Example 7]

[0266] [Preparation and surface treatment of silica-coated aluminum nitride particles with silanol groups (gas phase simultaneous film formation method)]

[0267] At the bottom of the SUS-made 8L pressure vessel, Add 3.0 g of 2,4,6,8-tetramethylcyclotetrasiloxane (D4H) to a 50 mL glass petri dish. Add 20g of 1N ammonia water to a 120°C glass petri dish and place them separately.

[0268] Place 200g of the above-mentioned silica-coated aluminum nitride particles A into... Place the 150°C glass petri dish on the SUS convex bottom grating plate atop an 8L SUS pressure vessel, cover with the lid of the 8L pressure vessel, and let stand in a sealed oven at 60°C for 10 minutes. After depressurization, perform CVD treatment again in a sealed oven at 60°C for 4 hours (D4H concentration: D4H partial pressure 7.66 × 10⁻⁶). 2 Pa (60℃) [CVD5 treatment] (gas phase film formation method).

[0269] Next, with respect to 100 parts by mass of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A, 2.4 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Silicone Co., Ltd., KBM-3103: decyltrimethoxysilane) was mixed by the dipping method to perform surface treatment (SC1 treatment). Note that the feeding ratio of the silane coupling agent was set to 90. Then, after standing for 2 hours at room temperature to perform drying, a dry machine was used to perform heat treatment at 120°C for 2 hours, thereby obtaining a sample of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A that had been surface-treated with the silane coupling agent.

[0270] [Example 8]

[0271] In Example 5, the treatment temperature of ammonia was set to 50°C, the treatment time was set to 4 hours, and otherwise the same operation as in Example 5 was performed to obtain a sample of the silicon-alcohol-group-introduced silica-coated aluminum nitride particles A that had been surface-treated with the silane coupling agent.

[0272] [Example 9]

[0273] In Example 5, the silica-coated aluminum nitride particles A were changed to the silica-coated aluminum nitride particles B, the treatment temperature of ammonia was set to 50°C, the treatment time was set to 4 hours, and the feeding ratio of the silane coupling agent was set to 2, and otherwise the same operation as in Example 5 was performed to obtain a sample of the silica-coated aluminum nitride particles B that had been surface-treated with the silane coupling agent.

[0274] [Example 10]

[0275] In Example 5, the silica-coated aluminum nitride particles A were changed to boron nitride particles A (UHP-1K: manufactured by Resonac Corporation) having a cumulative volume 50% particle diameter (D50) of 8.5 μm and a specific surface area obtained by the BET method of 4 m 2 / g, the treatment temperature of ammonia was set to 50°C, the treatment time was set to 4 hours, and the feeding ratio of the silane coupling agent was set to 2, and otherwise the same operation as in Example 5 was performed to obtain a sample of the boron nitride particles A that had been surface-treated with the silane coupling agent.

[0276] [Example 11]

[0277] In Example 5, the silica-coated aluminum nitride particles A were changed to boron nitride particles A (UHP-1K: manufactured by Resonac Corporation) having a cumulative volume 50% particle diameter (D50) of 8.5 μm and a specific surface area obtained by the BET method of 4 m 2Boron nitride particles B (UHP-S2: manufactured by Resonac Corporation) were used, the treatment temperature of ammonia was set to 50°C, the treatment time was set to 4 hours, the feeding ratio of silane coupling agent was set to 2, and the same operations as in Example 5 were performed except for these, to obtain a sample of boron nitride particles B in which the surface of boron nitride particles B to which silanol groups were introduced was treated with a silane coupling agent.

[0278] [Example 12]

[0279] In Example 8, the silane coupling agent treatment was not performed, and the same operations as in Example 8 were performed except for this, to obtain a sample of silica-coated aluminum nitride particles A in which silanol groups were introduced.

[0280] [Comparative Example 1]

[0281] In Example 1, the CVD treatment and the ammonia treatment were not performed, and the same operations as in Example 1 were performed except for this, to obtain a sample of silica-coated aluminum nitride particles A in which the surface of silica-coated aluminum nitride particles A was treated with a silane coupling agent.

[0282] [Comparative Example 2]

[0283] In Example 1, the ammonia treatment was not performed, and the same operations as in Example 1 were performed except for this, to obtain a sample of silica-coated aluminum nitride particles A in which the surface of silica-coated aluminum nitride particles A was treated with a silane coupling agent.

[0284] [Comparative Example 3]

[0285] In Example 1, the silica-coated aluminum nitride particles A were changed to aluminum nitride particles A, the CVD treatment and the ammonia treatment were not performed, and the same operations as in Example 1 were performed except for this, to obtain a sample of aluminum nitride particles A in which the surface of aluminum nitride particles A was treated with a silane coupling agent.

[0286] [Comparative Example 4]

[0287] In Example 1, the CVD treatment and the ammonia treatment were not performed, and the silane coupling agent treatment was not performed for the bulk method, and thus the silica-coated aluminum nitride particles A were prepared.

[0288] [Comparative Example 5]

[0289] In Example 1, the CVD treatment and the ammonia treatment were not performed, the mixing method of the silane coupling agent was changed from the immersion method to the dry mixing method, the feeding ratio of the silane coupling agent was changed to 3, and the same operations as in Example 1 were performed except for these, to obtain a sample of silica-coated aluminum nitride particles A in which the surface of silica-coated aluminum nitride particles A was treated with a silane coupling agent.

[0290] [Comparative Example 6]

[0291] In Example 1, the CVD treatment and the ammonia treatment were not performed, the silane coupling agent was changed from KBM-3103 to SZ-31, the addition rate of the silane coupling agent was set to 5, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the silica-coated aluminum nitride particle A whose surface was treated with the silane coupling agent.

[0292] [Comparative Example 7]

[0293] In Example 1, the ammonia treatment was not performed, the silane coupling agent was changed from KBM-3103 to SZ-31, the addition rate of the silane coupling agent was set to 5, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the silica-coated aluminum nitride particle A whose surface was treated with the silane coupling agent.

[0294] [Comparative Example 8]

[0295] In Example 9, the CVD treatment, the ammonia treatment, and the silane coupling agent treatment were not performed, and the silica-coated aluminum nitride particle B was used, and otherwise, the same operation as in Example 9 was performed to obtain a sample.

[0296] [Comparative Example 9]

[0297] In Example 1, the silica-coated aluminum nitride particle A was changed to the silica-coated aluminum nitride particle B, the CVD treatment and the ammonia treatment were not performed, the addition rate of the silane coupling agent was set to 2, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the silica-coated aluminum nitride particle B whose surface was treated with the silane coupling agent.

[0298] [Comparative Example 10]

[0299] In Example 1, the silica-coated aluminum nitride particle A was changed to the boron nitride particle A, the CVD treatment and the ammonia treatment were not performed, the addition rate of the silane coupling agent was set to 2, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the boron nitride particle A whose surface was treated with the silane coupling agent.

[0300] [Comparative Example 11]

[0301] In Example 1, the silica-coated aluminum nitride particle A was changed to the boron nitride particle B, the CVD treatment and the ammonia treatment were not performed, the addition rate of the silane coupling agent was set to 2, and otherwise, the same operation as in Example 1 was performed to obtain a sample of the boron nitride particle B whose surface was treated with the silane coupling agent.

[0302] [Measurement of Carbon Atom Content (ΔT-C)]

[0303] The carbon content of the samples obtained in the examples and comparative examples was measured by using a carbon-sulfur analyzer (Carbon Analyzer EMIA-821: HORIBA, Ltd.) based on a tubular electric furnace method, and measuring the samples before and after the introduction of silanol groups and the subsequent surface treatment agent treatment. The carbon increase amount (mass %) in the surface treatment step after the introduction of silanol groups was designated as ΔT-C. The value of this carbon increase amount was used as a reference for the amount of surface treatment agent attached. The results are shown in Tables 1 and 2.

[0304] [Measurement of slurry flow viscosity]

[0305] Examples 1 to 8, 12 and Comparative Examples 1 to 3, 5 to 7

[0306] Each of the particles obtained in Examples 1 to 8, 12 and Comparative Examples 1 to 3, 5 to 7, aluminum nitride particles TFZ-S30P, aluminum oxide particles AA-3, aluminum oxide particles AA-18, zinc oxide HD-01, silicone oil TSF458-50, and silicone resin raw material EG-3100 (A) were placed in a 150-ml special plastic container in such a manner that the slurry composition (mass parts) described in Tables 1 and 2 was formed, and a self-rotation-rotation mixer (Shinko Rika Co., Ltd., trade name: ARV-310P) was used to perform 6 times of stirring and mixing at 1500 rpm for 30 seconds and 3 times of stirring and mixing at 2000 rpm for 30 seconds under reduced pressure, thereby obtaining a slurry. The flow tester (Shimadzu Corporation, model: "CFT-EX") was used to measure the flow viscosity of the obtained slurry under a nozzle 2 x 2 mmL, 30°C, and a 40-kg load. The results are shown in Tables 1 and 2.

[0307] Details of each component are described below.

[0308] • TFZ-S30P: Insulating aluminum nitride heat conductive filler (trade name: Toyal Tech Filler, Toyal Aluminum KK, D50 = 30 μm)

[0309] • AA-3: High-purity alumina (trade name: Advanced Alumina (registered trademark), Sumitomo Chemical Co., Ltd., D50 = 3 μm)

[0310] • AA-18: High-purity alumina (trade name: Advanced Alumina, Sumitomo Chemical Co., Ltd., D50 = 18 μm)

[0311] • HD-01: Zinc oxide (trade name: Development product, Haku Sueki Co., Ltd., D50 = 0.5 μm)

[0312] • TSF458-50: heat-resistant oil (trade name: Straight Silicone Oil, manufactured by Momentive Performance Materials KK)

[0313] • EG-3100(A): A liquid of a silicone resin raw material (trade name: DOWSIL (registered trademark) EG-3100, manufactured by Dow Corning Toray Co., Ltd.) (viscosity: 420 mPa-s, a mixture of a vinyl oil and a platinum catalyst)

[0314] • Comparative Example 4

[0315] In the slurry composition (mass parts) described in Table 2, the silicone resin raw material EG-3100(A) and the silicone oil TSF458-50 as liquid components, and the silane coupling agent KBM3103 in an amount 3 times the amount capable of coating the nitride filler 43.6 parts calculated from the minimum coating area described in Example 1 were placed in a 150-ml special plastic container, and stirred for 30 seconds at a rotation speed of 2000 rpm once using a self-rotation-rotation mixer (manufactured by Shinkey Co., Ltd., trade name: ARV-310P). The particles of Comparative Example 4, the aluminum nitride particles TFZ-S30P, the alumina particles AA-3, the alumina particles AA-18, and the zinc oxide HD-01 were added thereto in a manner to form the slurry composition (mass parts) described in Table 2, and stirred and mixed for 30 seconds at a rotation speed of 1500 rpm for 6 times and at a rotation speed of 2000 rpm for 3 times while reducing the pressure using a self-rotation-rotation mixer (manufactured by Shinkey Co., Ltd., trade name: ARV-310P), to obtain a slurry. The flow viscosity of the obtained slurry was measured using a flow tester (manufactured by Shimadzu Corporation, model: "CFT-EX") under a condition of a nozzle diameter of 2 x 2 mm, a temperature of 30°C, and a load of 40 kg. The results are shown in Table 2. 2 x 2 mm L, 30°C, and a load of 40 kg. The results are shown in Table 2.

[0316] For details of each component of Comparative Example 4, the same substances as those described in Examples 1 to 8, 12 and Comparative Examples 1 to 3, 5 to 7 were used.

[0317] Example 9 and Comparative Examples 8 to 9

[0318] Each particle obtained in Example 9 and Comparative Examples 8 to 9, high-purity alumina AKP-30, and silicone resin raw material EG-3100 (A) were placed in a 150-ml special plastic container in such a manner as to form the slurry composition (mass parts) described in Tables 1 and 2, and a self-rotation-rotation mixing mixer (Shinko Co., Ltd., trade name: ARV-310P) was used to perform stirring mixing at 1,500 rpm for 30 seconds 6 times and at 2,000 rpm for 30 seconds 3 times under reduced pressure, thereby obtaining a slurry. A flow tester (Shimadzu Corporation, model: "CFT-EX") was used to measure the flow viscosity of the obtained slurry under a nozzle 0.5 x 1 mmL, 30°C, 80-kg load conditions. The results are shown in Tables 1 and 2.

[0319] Details of each component are described below.

[0320] • AKP-30: High-purity alumina (trade name: AKP series, Sumitomo Chemical Co., Ltd., D50 = 0.26 μm)

[0321] • EG-3100 (A): A liquid of a silicone resin raw material (trade name: DOWSIL (registered trademark) EG-3100, manufactured by Dow Corning Toray Co., Ltd.) (viscosity: 420 mPa-s, a mixture of a vinyl oil and a platinum catalyst)

[0322] Example 10 and Comparative Example 10

[0323] Each particle obtained in Example 10 and Comparative Example 10 was placed in a 150-ml special plastic container together with silicone oil (trade name: KF-96-1000cs, manufactured by Shin-Etsu Chemical Co., Ltd.) in such a manner as to form the slurry composition (mass parts) described in Tables 1 and 2, and a self-rotation-rotation mixing mixer (Shinko Co., Ltd., trade name: ARV-310P) was used to perform stirring mixing at 1,500 rpm for 30 seconds 1 time and at 2,000 rpm for 30 seconds 2 times under reduced pressure, thereby obtaining a slurry. A flow tester (Shimadzu Corporation, model: "CFT-EX") was used to measure the flow viscosity of the obtained slurry under a nozzle 0.5 x 1 mmL, 30°C, 80-kg load conditions. The results are shown in Tables 1 and 2.

[0324] Example 11 and Comparative Example 11

[0325] The respective particles obtained in Example 11 and Comparative Example 11 were placed in a 150-ml special plastic container together with silicone oil (trade name: KF-96-1000cs, manufactured by Shin-Etsu Chemical Co., Ltd.) in the slurry composition (mass parts) described in Tables 1 and 2, and using a self-rotation-rotation mixing mixer (manufactured by Sanky Co., Ltd., trade name: ARV-310P), stirring and mixing was performed three times at a rotation speed of 1500 rpm for 30 seconds while reducing the pressure, to obtain a slurry. The flow viscosity of the obtained slurry was measured under a condition of 0.5 x 1 mm L, 30°C, and 60-kg load using a flow tester (manufactured by Shimadzu Corporation, model: "CFT-EX") with a nozzle of 2 mm in diameter. The results are shown in Tables 1 and 2.

[0326] [Measurement of average surface density of silanol groups]

[0327] The measurement of the average surface density of silanol groups of each sample obtained in the examples and comparative examples was performed as follows.

[0328] First, 1 g of the sample was uniformly dispersed in a solution composed of chloroform 25 ml and pyridine 2 ml, and then, trifluoroacetic anhydride 0.1 mg was added to the obtained dispersion solution, and stirring was performed at 20°C for 1 hour and further at 40°C for 2 hours, and after allowing it to sufficiently react, the solid was filtered off and dried at 120°C for 2 hours. For the sample subjected to the above treatment, the amount of fluorine atoms was quantified by X-ray photoelectron spectroscopic analysis using a photoelectron spectrometer (model: JPS-9030, manufactured by JEOL Ltd.), and from the number of moles thereof, the number of silanol groups per unit area was calculated as the average surface density of silanol groups (number / nm 2 ). The results are shown in Tables 1 and 2.

[0329]

[0330] It was found that in Examples 1 to 9 (in which aluminum nitride particles were used as the nitride filler), in the 2A process of the manufacturing method of the nitride filler coated with the silicone compound having silanol groups, or the 2B process of the manufacturing method of the silicon dioxide-coated nitride filler coated with the silicone compound having silanol groups, the impregnation method, the vapor deposition method, or the vapor simultaneous deposition method was performed as the treatment method of the alkaline substance, and then, the surface treatment was performed, whereby more surface treatment agent was uniformly applied to the surface of the nitride filler, and thus it was possible to control the slurry flow viscosity at a low level and to mix the nitride filler at a high packing rate.

[0331] On the other hand, for Comparative Examples 1 to 9 which are at least not impregnation method, vapor deposition method, or vapor simultaneous deposition method (not having silanol group) of the treatment method as a basic substance, it is known that even if surface treatment is performed, the slurry flow viscosity is high, the slurry flow viscosity cannot be controlled at a low level, and the nitride filler cannot be mixed at a high packing rate.

[0332] In addition, it is known that in Comparative Examples 10, 11 which are not treated boron nitride, the slurry viscosity is high, and the nitride filler cannot be mixed at a high packing rate, compared to Examples 10, 11 which are treated with an organic silicon compound and then vapor deposition method is performed using a basic substance (use boron nitride particles as the nitride filler).

[0333] Further, it is known that the average surface density of the silanol group on the surface of the filler (filling material particles) of Examples 1 to 11 is higher than that of the filler (filling material particles) of Comparative Examples 1 to 11.

[0334] The silanol group on the surface of the filler easily bonds with the silane coupling agent through condensation, and it is presumed that this effectively exerts the original performance of the silane coupling agent, and contributes to the reduction of the slurry flow viscosity.

Claims

1. A method for manufacturing a silanol-based organosilicon compound-coated nitride filler, wherein the silanol-based organosilicon compound-coated nitride filler comprises a nitride filler and an organosilicon compound film covering the surface of the nitride filler and having silanol groups on the surface, the manufacturing method comprising: Step 1A, in which the surface of the nitride filler is covered with an organosilicon compound having a structure represented by the following general formula (1) to obtain an organosilicon compound-coated nitride filler covered with the organosilicon compound; and Step 2A, in which the surface of the organosilicon compound-coated nitride filler is treated with an alkaline substance to obtain an organosilicon compound-coated nitride filler with silanol groups on the surface. Or include: Step 1P involves coexisting an organosilicon compound containing the structure represented by the following general formula (1) and an alkaline substance in the same atmosphere, while simultaneously treating the organosilicon compound and the alkaline substance to cover the surface of the nitride filler, thereby obtaining an organosilicon compound-coated nitride filler with silanol groups on the surface. In formula (1), R is an alkyl group with 1 to 4 carbon atoms.

2. The method for manufacturing a silanol-based organosilicon compound-coated nitride filler according to claim 1, wherein in step 2A, the alkaline substance is ammonia, and the treatment is carried out by immersion in the ammonia.

3. The method for manufacturing a nitride filler containing an organosilicon compound with a silanol group according to claim 1, wherein in step 2A, the alkaline substance is ammonia water, and the treatment is carried out by chemical vapor deposition, i.e., CVD.

4. The method for manufacturing a nitride filler containing an organosilicon compound with a silanol group according to claim 1, wherein in the first P step, the alkaline substance is ammonia, and the treatment is performed simultaneously with the organosilicon compound by chemical vapor deposition, i.e., CVD.

5. The method for manufacturing a nitride filler containing an organosilicon compound with a silanol group according to claim 1, wherein the nitride filler is aluminum nitride particles or boron nitride particles.

6. The method for manufacturing a silanol-based organosilicon compound-coated nitride filler according to claim 5, wherein the cumulative volume 50% particle size D50 of the aluminum nitride particles is 0.1 μm or more and 200 μm or less.

7. The method for manufacturing a silanol-based organosilicon compound-coated nitride filler according to claim 1, wherein the surface treatment agent is attached to the surface of the silanol-based organosilicon compound-coated nitride filler by reaction or interaction.

8. The method for manufacturing a nitride filler containing an organosilicon compound with a silanol group according to claim 7, wherein the surface treatment agent is a silane coupling agent.

9. A nitride filler coated with an organosilicon compound having silanol groups, comprising a nitride filler and an organosilicon compound film having silanol groups covering the surface of the nitride filler, wherein the silanol groups are distributed on the surface at a density of 0.5 to 2.1 per nm. 2 The average surface density exists.

10. The organosilicon compound-coated nitride filler with silanol groups according to claim 9, wherein, The surface of the nitride filler containing organosilicon compounds with silanol groups also has a surface treatment agent.

11. The organosilicon compound-coated nitride filler with silanol groups according to claim 10, wherein the surface treatment agent is a silane coupling agent.

12. A method for manufacturing a silica-coated nitride filler having silanol groups and containing an organosilicon compound, the silica-coated nitride filler having silanol groups and containing an organosilicon compound film covering the surface of the silica-coated nitride filler and having silanol groups on the surface, the manufacturing method comprising: Step 1B, in which the surface of the silica-coated nitride filler is covered with an organosilicon compound containing the structure represented by the following general formula (1), to obtain a silica-coated nitride filler covered with the organosilicon compound and coated with the organosilicon compound; and Step 2B, in which the surface of the silica-coated nitride filler covered with the organosilicon compound is treated with an alkaline substance to obtain a silica-coated nitride filler with the organosilicon compound having silanol groups on the surface. Or include: In step 1Q, an organosilicon compound containing the structure represented by the following general formula (1) and an alkaline substance coexist in the same atmosphere, while the organosilicon compound and the alkaline substance are treated to cover the surface of the silica-coated nitride filler, thereby obtaining a silica-coated nitride filler with organosilicon compound coating having silanol groups on the surface. In formula (1), R is an alkyl group with 1 to 4 carbon atoms.

13. The method for manufacturing a silica-coated nitride filler with an organosilicon compound having a silanol group according to claim 12, wherein in step 2B, the alkaline substance is ammonia water, and the treatment is carried out by immersion in the ammonia water.

14. The method for manufacturing a silica-coated nitride filler with an organosilicon compound having a silanol group according to claim 12, wherein in step 2B, the alkaline substance is ammonia water, and the treatment is carried out by chemical vapor deposition, i.e., CVD.

15. The method for manufacturing a silica-coated nitride filler with an organosilicon compound having a silanol group according to claim 12, wherein in the first Q step, the alkaline substance is ammonia, and the treatment is performed simultaneously with the organosilicon compound by chemical vapor deposition, i.e., CVD.

16. The method for manufacturing a silica-coated nitride filler with an organosilicon compound having a silanol group according to claim 12, wherein the nitride filler is aluminum nitride particles or boron nitride particles.

17. The method for manufacturing a silica-coated nitride filler with an organosilicon compound containing a silanol group according to claim 16, wherein the cumulative volume 50% particle size D50 of the aluminum nitride particles is 0.1 μm or more and 200 μm or less.

18. The method for manufacturing a silica-coated nitride filler having a silanol group and containing an organosilicon compound as claimed in claim 12, wherein the surface treatment agent is attached to the surface of the silica-coated nitride filler having a silanol group and containing an organosilicon compound by reaction or interaction.

19. The method for manufacturing a silica-coated nitride filler with an organosilicon compound having a silanol group according to claim 18, wherein the surface treatment agent is a silane coupling agent.

20. A silica-coated nitride filler having silanol groups coated with an organosilicon compound, comprising a silica-coated nitride filler and an organosilicon compound film having silanol groups covering the surface of the silica-coated nitride filler, wherein the silanol groups are distributed on the surface at a density of 0.5 to 2.1 per nm. 2 The average surface density exists.

21. The silica-coated nitride filler with an organosilicon compound containing a silanol group according to claim 20, wherein the surface of the silica-coated nitride filler with an organosilicon compound containing a silanol group further comprises a surface treatment agent.

22. The silica-coated nitride filler with an organosilicon compound coating having a silanol group according to claim 21, wherein the surface treatment agent is a silane coupling agent.

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