Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/28—Nitrogen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/02—Ingredients treated with inorganic substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/04—Ingredients treated with organic substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/04—Ingredients treated with organic substances
  • C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/40—Compounds of aluminium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/10—Treatment with macromolecular organic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/12—Treatment with organosilicon compounds

Definitions

• the present invention relates to an aluminum nitride filler, a method for producing an aluminum nitride filler, a resin composition, and a method for producing a resin composition.
• Nitride fillers have high thermal conductivity and excellent electrical insulation. For this reason, nitride fillers are promising as fillers for resin compositions used in products such as heat dissipation sheets and sealing materials for electronic components.
• aluminum nitride undergoes hydrolysis when it reacts with moisture, turning into aluminum hydroxide, which has low thermal conductivity. Furthermore, aluminum nitride also produces ammonia, which is corrosive, during hydrolysis.
• Technologies for improving the moisture resistance of aluminum nitride include a method of forming a layer made of Si-Al-O-N on the surface of aluminum nitride powder (see, for example, Patent Document 1), a method of forming a coating layer on the surface of aluminum nitride powder using a silicate treatment agent and a coupling agent (see, for example, Patent Document 2), a method of treating the surface of aluminum nitride powder with a silicate treatment agent to leave organic groups on the surface (see, for example, Patent Document 3), a method of surface-modifying the surface of aluminum nitride particles with a specific acidic phosphate ester (see, for example, Patent Document 4), and an improved method that maintains better moisture resistance and thermal conductivity (see, for example, Patent Document 5).
• a layer of silicate ester is applied to the surface of the aluminum nitride powder, and then the powder is fired at a high temperature of 350 to 1000°C to form a layer of Si-Al-O-N on the surface.
• a coating layer is formed on the surface by performing a high-temperature heat treatment after surface treatment with a silicate treatment agent and a coupling agent.
• the surface is treated with a silicate treatment agent, and then heat treated at a temperature not exceeding 90°C, leaving organic groups, improving compatibility with resins.
• the surface-modified particles are aluminum nitride particles that have been surface-modified with a specific acidic phosphate ester to improve moisture resistance.
• the surface-modified particles are excellent moisture-resistant aluminum nitride particles coated with an extremely thin, uniform, and dense silica film.
• Boron nitride is also used in various heat dissipation components due to its high thermal conductivity, does not have the moisture resistance problem of aluminum nitride, and is also being developed for a variety of applications, taking advantage of its low dielectric constant.
• the primary particles are plate-shaped, and there are few active sites on which silane coupling agents can be effective, and they are localized on the end faces, so there are problems with compatibility with resins and the slurry viscosity tends to be high, especially when boron nitride is highly loaded.
• resin compositions that contain aluminum nitride filler and epoxy resin and are used in products such as heat dissipation sheets and sealing materials for electronic components are required to have good adhesive strength so that they can be used in a variety of applications.
• the present invention has been made in consideration of these circumstances, and aims to provide an aluminum nitride filler that can suppress an increase in viscosity when mixed with an epoxy resin and can suppress a decrease in adhesive strength after curing of an epoxy resin-containing resin composition, a method for producing the aluminum nitride filler, a resin composition containing the aluminum nitride filler, and a method for producing the resin composition.
• the present invention has the following configuration.
• An aluminum nitride filler comprising: aluminum nitride particles; and a coating (a) containing a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain, and having a weight average molecular weight of 2,000 or more and 10,000 or less.
• a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain and having a weight average molecular weight of 2,000 or more and 10,000 or less.
• the aluminum nitride filler according to the above [1] which contains a silicon-containing oxide coating (b).
• the aluminum nitride filler according to the above [1] or [2] which contains an organosilicon compound coating (c) having a silanol group.
• a method for producing an aluminum nitride filler comprising: aluminum nitride particles; and a coating (a) containing a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain and having a weight average molecular weight of 2,000 or more and 10,000 or less, the method comprising the steps of: A method for producing an aluminum nitride filler, comprising a fourth step of forming the coating film (a). [10] A first step of coating with an organosilicon compound having active hydrogen; and a second step of forming a silicon-containing oxide coating (b) by heating.
• a resin composition comprising the aluminum nitride filler according to any one of [1] to [8] above and an epoxy resin.
• a step II-1 of obtaining a composition i containing the compound (A) and the epoxy resin comprising step II-2 of adding and mixing at least one type of particle selected from aluminum nitride particles, particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, particles containing an organosilicone compound coating (c) and aluminum nitride particles, and particles containing a silicon-containing oxide coating (b), an organosilicone compound coating (c), and aluminum nitride particles, to composition i.
• the present invention provides an aluminum nitride filler that can suppress an increase in viscosity when mixed with an epoxy resin and can suppress a decrease in adhesive strength after curing of an epoxy resin-containing resin composition, a method for producing the aluminum nitride filler, a resin composition containing the aluminum nitride filler, and a method for producing the resin composition.
• D50 50% cumulative volume particle size
• D50 is determined from the particle size distribution using a laser diffraction scattering method. Specifically, it can be measured using a laser diffraction/scattering type particle size distribution measuring device (manufactured by Microtrac Bell Co., Ltd., product name: Microtrac MT3300EX2) or the like.
• the aluminum nitride filler of the present invention contains aluminum nitride particles and a coating (a) containing a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain and having a weight average molecular weight of 2,000 or more and 10,000 or less.
• a coating (a) containing the compound (A) an increase in viscosity when mixed with an epoxy resin can be suppressed, and a decrease in adhesive strength after curing of the epoxy resin-containing resin composition can be suppressed.
• the aluminum nitride particles used as a raw material can be any known product such as a commercially available product.
• the method for producing aluminum nitride particles is not particularly limited, and examples thereof include a direct nitridation method in which metallic aluminum powder is directly reacted with nitrogen or ammonia, and a reduction-nitridation method in which alumina is carbon-reduced while being heated in a nitrogen or ammonia atmosphere to simultaneously carry out a nitridation reaction.
• the aluminum nitride particles may be particles that have been sintered to form granules from aggregates of aluminum nitride particles.
• sintered granules made from high-purity aluminum nitride particles can be preferably used.
• the high-purity aluminum nitride particles refer to particles having a low oxygen content and a small amount of metal impurities.
• high-purity aluminum nitride particles having an oxygen content of 1 mass% or less and a total content of metal impurities (i.e., metal atoms other than aluminum) of 1000 mass ppm or less are suitable for obtaining higher thermal conductivity of the aluminum nitride particles contained in the aluminum nitride filler.
• the aluminum nitride particles can be used alone or in combination.
• the oxygen content described above can be measured using an inorganic analyzer equipped with an infrared detector for oxygen detection.
• the oxygen content can be measured using an oxygen, nitrogen, and hydrogen analyzer (ONH836: manufactured by LECO Japan LLC) or the like.
• the total content of metal atoms other than aluminum can be measured using an ICP (Inductively Coupled Plasma) mass spectrometer. Specifically, the total content of metal atoms other than aluminum can be measured using an ICP mass spectrometer (ICPMS-2030: manufactured by Shimadzu Corporation).
• ICPMS-2030 manufactured by Shimadzu Corporation.
• the shape of the aluminum nitride particles used in the present invention is not particularly limited, and examples include amorphous (crushed), spherical, elliptical, and plate-like (scale-like) shapes.
• the aluminum nitride particles may be the same type of aluminum nitride particles (single particles) having the same shape and structure, but they may also be used in the form of a mixture of aluminum nitride particles in which two or more different types of aluminum nitride particles having different shapes and structures are mixed in various ratios.
• the cumulative 50% volume particle size (D50) of the aluminum nitride particles used in the present invention is not particularly limited, but is preferably 0.1 ⁇ m or more, more preferably 0.3 ⁇ m to 200.0 ⁇ m, even more preferably 0.4 ⁇ m to 100.0 ⁇ m, and particularly preferably 0.5 ⁇ m to 85.0 ⁇ m.
• the D50 of the aluminum nitride particles is within the above-mentioned range, even when a resin composition containing aluminum nitride filler is used as a heat dissipation material for mounting power electronic components, it becomes possible to supply a thin heat dissipation material with a minimum thickness, and the moisture resistance of the aluminum nitride filler is further improved, probably because the coating easily covers the surface of the aluminum nitride particles uniformly.
• the coating (a) contained in the aluminum nitride filler of the present invention contains a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain, and having a weight average molecular weight of 2,000 or more and 10,000 or less.
• the content of compound (A) in coating (a) is not particularly limited, but from the viewpoint of suppressing an increase in viscosity and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition, it is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 98% by mass or more, and may be 100% by mass. That is, coating (a) may be formed from compound (A).
• the coating (a) may be formed adjacent to the aluminum nitride particle, or may be formed on the aluminum nitride particle via another layer, such as a silicon-containing oxide coating (b) or an organosilicon compound coating (c) having a silanol group, which will be described later.
• a silicon-containing oxide coating (b) or an organosilicon compound coating (c) having a silanol group which will be described later.
• it is preferable that the coating (a) is formed as the outermost layer of the aluminum nitride filler.
• the coating (a) may contain, in addition to the compound (A), a dispersant such as a surface treatment agent, a tackifier, and the like, if necessary.
• a dispersant such as a surface treatment agent, a tackifier, and the like, if necessary.
• dispersants include DISPERBYK106, BYK-W9010, BYK-P104 (all manufactured by BYK Japan KK), and FLOWRENE G700 (Kyoeisha Chemical Co., Ltd.).
• tackifiers include hydrogenated petroleum resin Alcon M-90 (Arakawa Chemical Industries Co., Ltd.), terpene resin YS RESIN TO-85, and YS POLYSTAR T80 (all manufactured by Yasuhara Chemical Co., Ltd.).
• the compound (A) contained in the coating (a) contained in the aluminum nitride filler of the present invention has a polyethyleneimine skeleton and a polyalkylene oxide chain, and has a weight average molecular weight of 2,000 or more and 10,000 or less.
• the polyethyleneimine backbone has ethyleneimine (-CH 2 CH 2 NH-) as its building block. This polyethyleneimine backbone can be branched when the hydrogen on the nitrogen is replaced by another chain of ethyleneimine building blocks.
• the polyethyleneimine backbone includes not only those having a completely linear structure, but also those having a branched chain structure containing primary, secondary and tertiary amino nitrogens.
• the polyethyleneimine skeleton preferably has 3 to 10 nitrogen atoms in one molecule, from the viewpoints of suppressing an increase in viscosity and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition.
• the alkylene oxide in the polyalkylene oxide chain is preferably an alkylene oxide having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, oxetane, butylene oxide, and tetrahydrofuran.
• propylene oxide is preferred from the viewpoint of suppressing an increase in viscosity and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition.
• compound (A) has 1 to 10 polyalkylene oxide chains with 8 to 15 repeating units as side chains.
• the viscosity increase of the resulting resin composition can be suppressed by adding a general surfactant, etc.
• a general surfactant, etc. when a general surfactant, etc. is added, the adhesive strength at the interface between the aluminum nitride particles or the filler containing aluminum nitride particles and the epoxy resin decreases, and the strength of the cured product of the resulting resin composition decreases, and the adhesive strength at the phase interface also decreases.
• compound (A) since compound (A) has a polyethyleneimine skeleton and a polyalkylene oxide chain, not only can an increase in viscosity of the resin composition be suppressed, but also a decrease in adhesive strength at the interface between the aluminum nitride filler and the epoxy resin can be suppressed, and a decrease in adhesive strength at the phase interface can be suppressed.
• the weight average molecular weight of the compound (A) is not particularly limited as long as it is from 2,000 to 10,000. From the viewpoint of further suppressing an increase in viscosity when mixed with an epoxy resin and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition, the weight average molecular weight is preferably from 2,500 to 9,000, more preferably from 3,000 to 7,000, and even more preferably from 3,500 to 6,000. In this specification, the weight average molecular weight is a value measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and specifically, it can be measured by the method described in the Examples.
• MALDI-TOF MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
• the content of compound (A) in the aluminum nitride filler is preferably 5.0 ⁇ 10-4 g or more and less than 5.0 ⁇ 10-2 g, more preferably 2.0 ⁇ 10-3 g or more and 4.0 ⁇ 10-2 g or less, and even more preferably 4.0 ⁇ 10-3 g or more and 3.5 ⁇ 10-2 g or less, per m2 of surface area calculated from the specific surface area ( m2 /g) of the aluminum nitride particles determined by the BET method, from the viewpoint of further suppressing the increase in viscosity when mixed with an epoxy resin and suppressing a decrease in adhesive strength after curing of the epoxy resin - containing resin composition .
• the specific surface area (m 2 /g) determined by the BET method is a value measured by a nitrogen adsorption BET single point method using a gas flow method.
• Macsorb HM model-1220 manufactured by Mountech can be used as an evaluation device.
• the content of compound (A) in the aluminum nitride filler is, from the viewpoint of further suppressing an increase in viscosity when mixed with an epoxy resin and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition, preferably 5.0 ⁇ 10-4 g or more and less than 5.0 ⁇ 10-2 g, more preferably 2.0 ⁇ 10-3 g or more and 4.0 ⁇ 10-2 g or less, and even more preferably 4.0 ⁇ 10-3 g or more and 3.5 ⁇ 10-2 g or less per m2 of surface area calculated from the specific surface area (m2/g) determined by the BET method of the particles containing the silicon-containing oxide coating (b) and the aluminum nitride particles.
• the content of compound (A) in the aluminum nitride filler is, from the viewpoint of further suppressing an increase in viscosity when mixed with an epoxy resin and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition, preferably 5.0 ⁇ 10-4 g or more and less than 5.0 ⁇ 10-2 g, more preferably 2.0 ⁇ 10-3 g or more and 4.0 ⁇ 10-2 g or less, and even more preferably 4.0 ⁇ 10-3 g or more and 3.5 ⁇ 10-2 g or less per m2 of surface area calculated from the specific surface area (m2 / g) determined by the BET method of the particles containing the organosilicon compound coating (c) having a silanol group and the aluminum nitride particles.
• the content of compound (A) in the aluminum nitride filler is, from the viewpoint of further suppressing an increase in viscosity when mixed with an epoxy resin and suppressing a decrease in adhesive strength after curing of the epoxy resin-containing resin composition, preferably 5.0 ⁇ 10-4 g or more and less than 5.0 ⁇ 10-2 g, more preferably 2.0 ⁇ 10-3 g or more and 4.0 ⁇ 10-2 g or less, and even more preferably 4.0 ⁇ 10-3 g or more and 3.5 ⁇ 10-2 g or less per m2 of surface area calculated from the specific surface area ( m2 /g) determined by the BET method of the particles containing the silicon-containing oxide coating (b), the organosilicon compound coating ( c ) having a silanol group , and the aluminum nitride particles.
• the aluminum nitride filler of the present invention may contain a silicon-containing oxide coating (b).
• the aluminum nitride filler contains the silicon-containing oxide coating (b)
• the moisture resistance is improved.
• the "silicon-containing oxide” in the silicon-containing oxide coating (b) includes silica and composite oxides of silicon and aluminum.
• the term “oxide” also includes oxynitrides, oxycarbonitrides, and the like.
• the content of the silicon-containing oxide coating (b) in the aluminum nitride filler is preferably 0.8 ⁇ 10 ⁇ 5 to 2.5 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO 2 ], more preferably 1.0 ⁇ 10 ⁇ 4 to 2.0 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO 2 ], and even more preferably 2.0 ⁇ 10 ⁇ 4 to 1.5 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO 2 ].
• the content of the silicon-containing oxide coating (b) in the aluminum nitride filler can be determined by dividing the content of silicon atoms ( ⁇ Si amount) measured by ICP atomic emission spectrometry by the surface area (m 2 ) calculated from the specific surface area (m 2 /g) of the aluminum nitride filler determined by the BET method.
• the silicon atom content ( ⁇ Si amount) in the silicon-containing oxide coating (b) is preferably 20 to 2,000 ppm by mass, more preferably 30 to 1,950 ppm by mass, and even more preferably 40 to 1,900 ppm by mass.
• the amount of ⁇ Si can be measured by ICP emission spectrometry.
• the silicon-containing oxide coating (b) can be formed by the ⁇ Production method of aluminum nitride filler> described below. In addition, it is preferable that the silicon-containing oxide coating (b) is formed using the ⁇ Organic silicone compound> described below as a raw material.
• the silicon-containing oxide coating (b) is preferably formed on the surface of the aluminum nitride particles from the viewpoint of further improving moisture resistance.
• the aluminum nitride filler of the present invention contains the silicon-containing oxide coating (b)
• the aluminum nitride filler of the present invention may further contain an organosilicon compound coating (c) having a silanol group (hereinafter, sometimes simply referred to as "organosilicon compound coating (c)"). Since the organosilicon compound coating (c) has a high affinity with compound (A), when the aluminum nitride filler contains the organosilicon compound coating (c), the interfacial adhesive strength between the resin contained in the resin composition described below and the aluminum nitride filler is improved, and when the resin composition is laminated and molded, the adhesive strength at the layer interface is improved.
• organosilicon compound coating (c) having a silanol group
• the organosilicon compound coating (c) contains an organosilicon compound having a structure represented by the following formula (i):
• R 1 is an alkyl group having 1 to 4 carbon atoms.
• the organosilicon compound containing the structure represented by formula (i) above may be linear, cyclic, or branched.
• the content of the organosilicon compound containing the structure represented by the above formula (i) in the organosilicon compound coating (c) is not particularly limited, but from the viewpoint of suppressing a decrease in the interfacial adhesive strength between the resin contained in the resin composition and the aluminum nitride filler, it is preferably 80 mass% or more, more preferably 90 mass% or more, and even more preferably 98 mass% or more, and may be 100 mass%. That is, the organosilicon compound coating (c) may be formed from an organosilicon compound containing the structure represented by the above formula (i).
• the content of the organosilicon compound containing the structure represented by the above formula (i) in the organosilicon compound coating (c) can be calculated by converting the value measured by ICP emission spectrometry.
• the content of the organosilicon compound coating (c) in the aluminum nitride filler is preferably 0.8 ⁇ 10 ⁇ 5 to 2.5 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO2], more preferably 1.0 ⁇ 10 ⁇ 4 to 2.0 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO2], and even more preferably 2.0 ⁇ 10 ⁇ 4 to 1.5 ⁇ 10 ⁇ 2 [g/m 2 equivalent to SiO2 ] .
• the content of the organosilicon compound coating (c) can be determined in the same manner as for the content of the silicon-containing oxide coating (b) in the aluminum nitride filler.
• the organosilicone compound coating (c) is preferably formed adjacent to the coating (a) from the viewpoint of suppressing a decrease in the interfacial adhesive strength between the resin contained in the resin composition and the aluminum nitride filler, and is preferably formed between the aluminum nitride particles and the coating (a) from the viewpoint of effectively obtaining the effects of the present invention.
• the aluminum nitride filler contains a silicon-containing oxide coating (b)
• the aluminum nitride particles and the silicon-containing oxide coating (b) are adjacent to each other, the surface of the silicon-containing oxide coating (b) opposite to the surface in contact with the aluminum nitride particles is adjacent to the organosilicone compound coating (c), and the coating (a) is formed as the outermost layer.
• the method for producing an aluminum nitride filler of the present invention is a method for producing the above-mentioned aluminum nitride filler. That is, the method for producing an aluminum nitride filler of the present invention is a method for producing an aluminum nitride filler containing aluminum nitride particles and a coating film (a) containing a compound (A) having a polyethyleneimine skeleton and a polyalkylene oxide chain and having a weight average molecular weight of 2000 to 10000, and includes a fourth step of forming the coating film (a).
• the method for producing an aluminum nitride filler of the present invention may include, in addition to the fourth step, a first step of coating with an organosilicon compound having active hydrogen, a second step of forming a silicon-containing oxide coating (b) by heating, or a third step of coating with an organosilicon compound having active hydrogen by vapor deposition, and treating with a basic substance to form an organosilicon compound coating (c) having a silanol group.
• the method for producing an aluminum nitride filler of the present invention may include, in addition to the fourth step, a first step of coating with an organosilicon compound having active hydrogen, and a second step of forming a silicon-containing oxide coating film (b) by heating.
• the method for producing an aluminum nitride filler of the present invention may also include a first step of coating with an organosilicon compound having active hydrogen, a second step of forming a silicon-containing oxide coating film (b) by heating, and a third step of forming an organosilicon compound coating film (c) having a silanol group by treating with a basic substance.
• the first to fourth steps will be described below.
• This step is a step of coating with an organosilicon compound having active hydrogen, and is carried out in order to form the silicon-containing oxide coating film (b).
• the objects to be coated with the organosilicon compound having active hydrogen are aluminum nitride particles and particles containing a silicon-containing oxide coating (b) and aluminum nitride particles.
• the organosilicon compound having active hydrogen used as a raw material for the silicon-containing oxide coating (b) is preferably an organosilicon compound containing a structure represented by the following formula (1) from the viewpoint of moisture resistance, and may be linear, cyclic, or branched.
• the structure represented by the following formula (1) is a hydrogen siloxane unit in which hydrogen is directly bonded to a silicon atom.
• R is an alkyl group having 1 to 4 carbon atoms.
• R which is an alkyl group having 1 to 4 carbon atoms, is preferably a methyl group, an ethyl group, a propyl group, a t-butyl group, etc., from the viewpoint of volatilizing the silicone compound, and the methyl group is particularly preferred.
• the organosilicone compound used as a raw material is, for example, an oligomer or polymer containing the structure represented by formula (1).
• organic silicone compound for example, at least one of the compounds represented by the following formula (2) and the compounds represented by the following formula (3) is suitable.
• R1 and R2 are each independently a hydrogen atom or a methyl group, at least one of R1 and R2 is a hydrogen atom, and m is an integer from 0 to 10.
• n is an integer from 3 to 6.
• the cyclic hydrogen siloxane oligomer in which n is 4 in the formula (3) is excellent in that it can form a uniform silicon-containing oxide film (b) on the surface of the object to be coated.
• the weight-average molecular weight of the organosilicone compound containing the structure shown in formula (1) is preferably 100 or more and 2000 or less, more preferably 150 or more and 1000 or less, and even more preferably 180 or more and 500 or less. It is presumed that by using an organosilicone compound containing the structure shown in formula (1) with a weight-average molecular weight in this range, it is easy to form a thin and uniform silicon-containing oxide film (b) on the surface of the object to be coated.
• m in formula (2) is 1.
• the method is not particularly limited as long as the surface of the object to be coated can be covered with the organic silicone compound.
• the method for the first step includes a dry mixing method in which the organic silicone compound is added by spraying or the like while stirring the object to be coated, and then dry-mixed to coat the object.
• powder mixing devices include a Henschel mixer, a container-rotating V-blender, a double-cone blender, a ribbon blender with mixing blades, a screw-type blender, a closed rotary kiln, and stirring with a stirrer in a closed container using a magnetic coupling.
• the temperature conditions in this case are not particularly limited, depending on the boiling point and vapor pressure of the organic silicone compound, but a preferred temperature is 10°C to 200°C, more preferably 20°C to 150°C, and even more preferably 40°C to 100°C.
• a gas-phase adsorption method can be used in which the vapor of the organosilicon compound alone or a mixed gas with an inert gas such as nitrogen gas is attached or deposited on the surface of the object to be coated that is placed still.
• the temperature conditions in this case depend on the boiling point and vapor pressure of the organosilicon compound, but the preferred temperature range is 10°C to 200°C, more preferably 20°C to 150°C, and even more preferably 40°C to 100°C.
• the treatment time is preferably 3 to 7 hours, and more preferably 3.5 to 5 hours. If necessary, the system can be pressurized or depressurized [sometimes called chemical vapor deposition (CVD) method].
• the equipment that can be used in this case is preferably a closed system and an equipment that can easily replace the gas in the system, such as a glass container, a desiccator, or a CVD device.
• the treatment time needs to be longer when the object to be coated is coated with the organosilicon compound without stirring.
• by intermittently placing the processing container on the vibrator it is possible to efficiently process powder in areas that are in the shade due to contact with other powder particles, or powder that is far from the air layer above, by moving the position.
• the amount of the organic silicone compound used in the first step is not particularly limited.
• the coating amount of the organic silicone compound containing a structure represented by formula (1) is preferably 0.08 mg or more and 20.0 mg or less per m2 of surface area calculated from the specific surface area ( m2 /g) of the object to be coated determined by the BET method, 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.
• the amount of the organosilicone compound having the structure represented by formula (1) coated per m2 of surface area calculated from the specific surface area ( m2 /g) of the object to be coated determined by the BET method can be determined by dividing the mass difference of the object to be coated before and after being coated with the organosilicone compound by the surface area ( m2 ) calculated from the specific surface area (m2/ g ) of the object to be coated determined by the BET method.
• the timing of the introduction of the organosilicon compound may be at any stage before the temperature is increased, as long as the reaction amount of the organosilicon compound is maintained.
• the silicon-containing oxide coating (b) is formed by heating the aluminum nitride particles coated with the organosilicon compound, or particles containing the silicon-containing oxide coating (b) coated with the organosilicon compound and aluminum nitride particles.
• the heating temperature in the second step is preferably 500°C or higher and 900°C or lower, more preferably 550°C or higher and 850°C or lower, and even more preferably 600°C or higher and 800°C or lower.
• a general heating furnace can be used as long as it can maintain the temperature within the above range.
• the heating temperature in the second step When the heating temperature in the second step is low, a silica coating is formed on the surface of the object to be coated, and silica-coated aluminum nitride particles can be produced. That is, the silicon-containing oxide coating (b) is formed as a silica coating.
• the heating temperature in the second step is high, a coating of a complex oxide of silicon and aluminum elements is formed on the surface of the object to be coated, and aluminum nitride particles coated with a complex oxide of silicon and aluminum elements can be produced. That is, the silicon-containing oxide coating (b) is formed as a coating of a complex oxide of silicon and aluminum elements.
• the silicon-containing oxide coating (b) is preferably a silica coating.
• silica coating means that it is coated with a thin film mainly composed of silica.
• ToF-SIMS Time of Flight Secondary Ion Mass Spectrometry, ION-TOF, TOF.SIMS5
• recombination of secondary ions and decomposition during ionization may overlap, and segments such as AlSiO 4 ions and SiNO ions may be detected simultaneously as subcomponents.
• the composite segments analyzed by this ToF-SIMS analysis can also be defined as partial detections when aluminum nitride is silicated.
• silica can be considered to be the main component.
• the carbon atom content can be measured using a carbon/sulfur analyzer that uses a non-dispersive infrared absorption method with a tubular electric furnace. Specifically, it can be measured using a carbon/sulfur analyzer (Carbon Analyzer EMIA-821: manufactured by Horiba, Ltd.).
• the heating temperature (heat treatment temperature) in the second step is 500°C or higher, the silicon-containing oxide coating (b) becomes dense and less permeable to moisture, resulting in better moisture resistance. Heating at 1000°C or lower results in better thermal conductivity and moisture resistance. If the heating temperature is 500°C or higher and 1000°C or lower, the silicon-containing oxide coating (b) is formed uniformly on the surface of the object to be coated. If the heating temperature is 500°C or higher, the silicon-containing oxide coating (b) has excellent insulating properties, and if the heating temperature is 1000°C or lower, it is also effective in terms of energy costs.
• the heating time is preferably from 2 to 10 hours, more preferably from 2 to 8 hours, and even more preferably from 2 to 7 hours.
• a heat treatment time of 2 hours or more is preferable in that no decomposition products of the organic group (alkyl group having 4 or less carbon atoms) of the organosilicon compound remain, and a silicon-containing oxide coating (b) with a very low carbon atom content is obtained on the surface of the object to be coated.
• a heating time of 7 hours or less is preferable in that the silicon-containing oxide coating (b) can be formed efficiently.
• the atmosphere for the heat treatment in the second step is not particularly limited, and may be, for example, an inert gas atmosphere such as N2 , Ar, or He, an atmosphere containing a reducing gas such as H2 , CO, or CH4 , or an atmosphere containing oxygen gas, for example, in the atmosphere (air).
• an inert gas atmosphere such as N2 , Ar, or He
• an atmosphere containing a reducing gas such as H2 , CO, or CH4
• an atmosphere containing oxygen gas for example, in the atmosphere (air).
• the first and second steps may be performed in sequence after the heat treatment in the second step. That is, the process of performing the first and second steps in sequence may be repeated.
• the coating method in which the surface of the object to be coated is covered with an organic silicone compound by gas-phase adsorption in the first step is preferable because it is possible to form a uniform and thin silicon-containing oxide coating (b) compared to a coating method using a liquid treatment. Therefore, even if the process of sequentially carrying out the first step and the second step is repeated multiple times, for example about 2 to 5 times, the aluminum nitride particles can exhibit good thermal conductivity.
• the number of times that the first and second steps are performed in sequence can be freely selected depending on the level of moisture resistance required for the actual application.
• an organosilicon compound having active hydrogen is coated on aluminum nitride particles by vapor deposition, and then treated with a basic substance to form an organosilicon compound coating (c) having a silanol group.
• the organosilicon compound coating (c) may be formed adjacent to the aluminum nitride particles, or after forming a silicon-containing oxide coating (b) on the aluminum nitride particle surface, the organosilicon compound coating (c) may be formed on the surface opposite to the surface where the silicon-containing oxide coating (b) contacts the aluminum nitride particles.
• the organosilicone compound coating (c) be adjacent to the coating (a).
• the method for coating the organosilicon compound having active hydrogen by vapor deposition in this step can be the same as the method for coating the organosilicon compound by vapor deposition in step 1.
• the organosilicon compound used in this step may be the same as or different from the organosilicon compound used in step 1.
• the organosilicon compound used in this step is preferably an organosilicon compound containing the structure represented by the above formula (1).
• the aluminum nitride particles are coated with an organosilicon compound having active hydrogen by vapor deposition, components other than the organosilicon compound having active hydrogen may or may not be coated. That is, the coating film coated by vapor deposition may contain components other than the organosilicon compound having active hydrogen, or may be formed from the organosilicon compound.
• an organosilicon compound is coated by vapor deposition, and then the --Si--H groups (active hydrogen groups) contained in the organosilicon compound are converted to --Si--OH groups (silanol groups) by treating with a basic substance.
• the basic substance is not particularly limited, and may range from a weak base to a strong base, from a Bronsted base to a Lewis base, so long as no strong base aqueous solution that remains as a solid is used, and examples of the basic substance include aqueous ammonia, monoethylamine, diethylamine, triethylamine, 2-ethanolamine, etc. From the viewpoint of ease of separation, aqueous ammonia is preferred.
• the treatment with a basic substance can be performed by immersion or vapor deposition.
• the immersion method is a film formation method in which an organosilicon compound coated by vapor deposition is immersed in an aqueous solution of a basic substance, etc., to cause the basic substance to act on the organosilicon compound, thereby converting -Si-H groups (active hydrogen groups) into -Si-OH groups (silanol groups).
• the aqueous solution of the basic substance is preferably aqueous ammonia.
• the concentration of the basic substance there are no particular limitations on the concentration of the basic substance, but for example, when ammonia water is used as the basic substance, the concentration is preferably 0.01N or more and 10N or less from the viewpoint of reaction rate, and more preferably 0.1N or more and 5N or less from the viewpoint of suppressing side reactions of residual organosilicon compounds and reducing the risk to the working environment, and even more preferably 0.5N or more and 1.5N or less.
• the amount of ammonia water is not particularly limited, but for example, when the particle diameter (D50) of the aluminum nitride particles used in the reaction is 30 ⁇ m or more and 100 ⁇ m or less, it is preferable to treat with ammonia water of a mass of at least one-third of the particle mass and a mass equal to or less than the particle mass. Also, when the particle diameter (D50) is 0.1 ⁇ m or more and less than 30 ⁇ m, it is preferable to treat with ammonia water of a mass of at least one-half of the particle mass and a mass equal to or less than twice the particle mass.
• the treatment temperature is preferably 20° C. or higher and 60° C. or lower, but since a large amount of hydrogen is generated immediately after treatment, it is preferable to start the treatment at 20° C. for safety reasons.
• the treatment time is preferably 20 hours or higher and 30 hours or lower, and more preferably 22 hours or higher and 27 hours or lower.
• the residue After the treatment of the basic substance is complete, it is preferable to filter the residue by suction filtration using filter paper, wash the residue thoroughly with distilled water, and then wash it with ethanol to make it easier to dry. To make it easier to dry, the residue may be washed with acetone. The residue may also be dried by heating it at 90 to 120°C for 2 to 4 hours.
• the vapor phase film formation method is a film formation method in which a basic substance is vapor-phase film formed on an organosilicon compound coated by vapor deposition using an aqueous solution of a basic substance, and the basic substance is allowed to act on the organosilicon compound, thereby converting -Si-H groups (active hydrogen groups) into -Si-OH groups (silanol groups).
• the aqueous solution of the basic substance is preferably aqueous ammonia.
• the concentration of the basic substance is not particularly limited, but for example, when ammonia water is used as the basic substance, it is preferable to carry out the method by opening a gas vent hole in an airtight container and placing it in a place where local exhaust can be performed.
• the concentration of ammonia water is preferably 0.01N or more and 10.0N or less, more preferably 0.10N or more and 5.0N or less from the viewpoint of suppressing the side reaction of residual organic silicone compounds and reducing the risk of working environment, and even more preferably 0.50N or more and 1.50N or less.
• the reaction rate is slower than in the immersion method using aqueous ammonia, so the treatment temperature is preferably 20° C.
• the treatment time for the vapor phase film formation method using aqueous ammonia is 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, in the case of treatment at 50° C., sufficient silanol groups can be introduced in 4 to 5 hours.
• organosilicon compound coating (c) by a gas phase film formation method, since this eliminates the need for filtration and drying processes and allows for efficient production.
• a coating (a) is formed.
• the coating (a) is formed on aluminum nitride particles, or particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, or particles containing an organic silicone compound coating (c) and aluminum nitride particles, or particles containing a silicon-containing oxide coating (b), an organic silicone compound coating (c) and aluminum nitride particles (hereinafter sometimes simply referred to as "particles").
• an aluminum nitride filler containing aluminum nitride particles and the coating (a) can be produced.
• the method for forming the coating (a) is not particularly limited, but it is preferably formed by the impregnation method or the integral method, and from the viewpoint of more effectively obtaining the effects of the present invention, it is more preferable to form it by the impregnation method.
• the impregnation method is a film-forming method in which the particles are immersed in a solution containing the compound (A) to form a coating (a) on the surfaces of the particles.
• solvents that can be used in the solution containing compound (A) include isopropanol, 1-methoxy-2-propanol, ethylene glycol monomethyl ether, dioxolane, etc. Among these, isopropanol is preferred from the viewpoint of the balance between volatility and solubility and from the viewpoint of not being highly toxic.
• the content of compound (A) in the solution containing compound (A) is preferably 8 to 30 mass%, more preferably 10 to 25 mass%, and even more preferably 15 to 20 mass%, from the viewpoint of efficiently forming the coating film (a).
• the solution containing compound (A) may contain components other than compound (A).
• the time for soaking the particles is preferably 10 to 60 minutes, more preferably 15 to 50 minutes, and even more preferably 20 to 40 minutes.
• the material After immersion, the material may be heated at 100-150°C for 1-3 hours to remove the solvent.
• the integral method is a film-forming method in which a resin such as an epoxy resin is mixed with a compound (A), and then aluminum nitride particles, or particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, or particles containing an organosilicone compound coating (c) and aluminum nitride particles, or particles containing a silicon-containing oxide coating (b), an organosilicone compound coating (c) and aluminum nitride particles, are added to the mixture and mixed, thereby forming a coating (a) on the surfaces of these particles.
• a resin such as an epoxy resin
• Al nitride particles or particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, or particles containing an organosilicone compound coating (c) and aluminum nitride particles, are added to the mixture and mixed, thereby forming a coating (a) on the surfaces of these particles.
• the resin to be mixed with compound (A) may be an epoxy resin, a phenol resin, a phenol novolac resin, a urethane resin, an acrylic resin, an epoxy phenol resin, an epoxy urethane resin, an epoxy acrylic resin, or the like, but epoxy-based resins are preferably used in the main.
• the content of compound (A) in a mixture obtained by mixing a resin such as an epoxy resin with compound (A) is preferably 0.03 to 3.0 mass%, more preferably 0.05 to 1.5 mass%, and even more preferably 0.08 to 0.8 mass%, from the viewpoint of more effectively obtaining the effects of the present invention.
• a mixture obtained by mixing a resin such as an epoxy resin with the compound (A) is used as a resin composition described later
• the content of the compound (A) in the mixture obtained by mixing a resin such as an epoxy resin with the compound (A) is preferably 0.03 to 3.0 mass%, more preferably 0.05 to 1.5 mass%, and even more preferably 0.08 to 0.8 mass%, from the viewpoint of more effectively obtaining the effects of the present invention.
• the amount of the particles added is such that the content of the particles in the resulting resin composition is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 60 to 80% by mass, from the viewpoint of more effectively obtaining the effects of the present invention.
• the method for producing the aluminum nitride filler preferably includes a first step of coating with an organosilicon compound having active hydrogen, a second step of forming the silicon-containing oxide coating (b) by heating, and a fourth step of forming the coating (a).
• the method for producing the aluminum nitride filler preferably comprises a third step of coating the aluminum nitride filler with an organosilicon compound having active hydrogen by vapor deposition, and treating the resulting product with a basic substance to form an organosilicon compound coating (c) having a silanol group, and a fourth step of forming the coating (a).
• the method for producing the aluminum nitride filler preferably comprises a first step of coating with an organosilicon compound having active hydrogen, a second step of forming the silicon-containing oxide coating (b) by heating, a third step of coating with an organosilicon compound having active hydrogen by vapor deposition, and treating with a basic substance to form the organosilicon compound coating (c) having silanol groups, and a fourth step of forming the coating (a).
• the resin composition of the present invention contains the aluminum nitride filler of the present invention and an epoxy resin. Since the resin composition of the present invention contains the aluminum nitride filler of the present invention, an increase in viscosity is suppressed and a decrease in adhesive strength after curing is also suppressed.
• the resin composition may contain, in addition to the aluminum nitride filler of the present invention, commonly used fillers such as boron nitride, alumina, silica, and zinc oxide.
• epoxy resins include bifunctional glycidyl ether type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, and biphenyl type epoxy resins; glycidyl ester type epoxy resins such as hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester; linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil; heterocyclic epoxy resins such as triglycidyl isocyanurate; and N,N,N',N'-tetraglycidyl-4,4'-diazotylene.
• bifunctional glycidyl ether type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, and biphenyl type epoxy resins
• glycidylamine-type epoxy resins such as dimethylaminodiphenylmethane, N,N,N',N'-tetraglycidyl-1,3-benzenedi(methanamine), 4-(glycidyloxy)-N,N-diglycidylaniline, and 3-(glycidyloxy)-N,N-diglycidylaniline; polyfunctional glycidyl ether-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, biphenyl aralkyl-type epoxy resins, naphthalene aralkyl-type epoxy resins, tetrafunctional naphthalene-type epoxy resins, and triphenylmethane-type epoxy resins; and the like.
• the above-mentioned epoxy resins can be used alone or in combination of two or more kinds.
• the coating (a) containing the compound (A) exhibits the most suitable viscosity reducing effect when used in combination with a bisphenol A type epoxy resin.
• the bisphenol A type epoxy resin may be used alone, or may be used in combination with a bisphenol A type epoxy resin and an epoxy resin other than the bisphenol A type epoxy resin, or may be used in combination with a bisphenol A type epoxy resin and a phenol novolac resin.
• a hardener and hardening accelerator may be added.
• the curing agent include alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and himic anhydride; aliphatic acid anhydrides such as dodecenylsuccinic anhydride; aromatic acid anhydrides such as phthalic anhydride and trimellitic anhydride; bisphenols such as bisphenol A, bisphenol F, and bisphenol S; phenol resins such as phenol-formaldehyde resin, phenol-aralkyl resin, naphthol-aralkyl resin, and phenol-dicyclopentadiene copolymer resin; organic dihydrazides such as dicyandiamide and adipic acid dihydrazide; and examples of the curing catalyst include amines such as tris(dimethylaminomethyl)phenol, dimethylbenzylamine, 1,
• the resin composition of the present invention may contain a resin other than an epoxy resin.
• the resin other than an epoxy resin is preferably a thermosetting resin, a thermoplastic resin, or a mixture of a thermosetting resin and a thermoplastic resin, since the resulting resin composition has excellent heat resistance.
• thermosetting resins include silicone resins such as polydimethylsiloxane, phenolic resins, bismaleimide resins, cyanate resins, urethane resins, (meth)acrylic resins, vinyl ester resins, unsaturated polyester resins, polyvinyl alcohol acetal resins, etc., and these can be used alone or in combination of two or more types.
• a mixture of a thermosetting resin with a curing agent and a curing accelerator may be used.
• the silicone resin may be an addition reaction curing type silicone resin, a condensation reaction curing type silicone resin, an organic peroxide curing type silicone resin, etc., and may be used alone or in combination of two or more types with different viscosities.
• the silicone resin may be, for example, an addition reaction curing type liquid silicone resin that does not produce by-products that may cause bubbles, etc., and a silicone resin cured product can be obtained by reacting an organopolysiloxane having an alkenyl group, which is the base polymer, with an organopolysiloxane having a Si-H group, which is the crosslinking agent, in the presence of a curing agent at room temperature or by heating.
• the organopolysiloxane which is the base polymer
• examples of the organopolysiloxane include those having, for example, a vinyl group, an allyl group, a propenyl group, a hexenyl group, etc., as the alkenyl group.
• the vinyl group is preferable as the organopolysiloxane.
• a platinum metal-based curing catalyst may be used as the curing catalyst, and the amount of addition may be adjusted to achieve the desired hardness of the cured resin.
• the resin composition of the present invention may further contain additives such as flexibility imparting agents such as silicone, urethane acrylate, butyral resin, acrylic rubber, diene rubber and copolymers thereof, silane coupling agents, titanium coupling agents, inorganic ion scavengers, pigments, dyes, diluents, solvents, etc., as required.
• flexibility imparting agents such as silicone, urethane acrylate, butyral resin, acrylic rubber, diene rubber and copolymers thereof, silane coupling agents, titanium coupling agents, inorganic ion scavengers, pigments, dyes, diluents, solvents, etc.
• the total content of aluminum nitride filler and fillers other than the aluminum nitride filler in the resin composition is not particularly limited as long as it is an amount that results in the desired resin composition, but is preferably 50% by mass or more and 90% by mass or less, more preferably 60% by mass or more and 88% by mass or less, and even more preferably 70% by mass or more and 85% by mass or less. If the total content is 50% by mass or more, good heat dissipation properties can be achieved, and if it is 90% by mass or less, good workability can be obtained when using the resin composition.
• the content of aluminum nitride filler in the components (fillers) other than the resin components of the resin composition is preferably 30% by mass or more and 100% by mass or less of the total content of the aluminum nitride filler and fillers other than the aluminum nitride filler, more preferably 40% by mass or more and 100% by mass or less, and even more preferably 50% by mass or more and 100% by mass or less. If the total content is 30% by mass or more, good heat dissipation properties can be achieved.
• the total content of epoxy resins and resins other than the epoxy resins in the resin composition is not particularly limited as long as it is an amount that results in the desired resin composition, but is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less. If the total content is 50% by mass or less, good heat dissipation properties can be achieved, and if it is 1% by mass or more, good workability can be obtained when using the resin composition.
• the content of the epoxy resin in the resin composition is preferably 30% by mass or more and 100% by mass or less of the total content of the epoxy resin and resins other than the epoxy resin, more preferably 35% by mass or more and 100% by mass or less, and even more preferably 40% by mass or more and 100% by mass or less. If the total content is 30% by mass or more, the increase in viscosity when mixed with the epoxy resin can be further suppressed, and the decrease in adhesive strength after curing of the epoxy resin-containing resin composition can be suppressed.
• the method for producing a resin composition of the present invention preferably includes the following step I, or the following steps II-1 and II-2.
• Step I a step of adding and mixing the aluminum nitride filler with the epoxy resin
• Step II-1 a step of obtaining a composition i containing the compound (A) and the epoxy resin
• Step II-2 a step of adding and mixing at least one type of particle selected from aluminum nitride particles, particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, particles containing an organosilicone compound coating (c) and aluminum nitride particles, and particles containing a silicon-containing oxide coating (b), an organosilicone compound coating (c), and aluminum nitride particles to the composition i.
• Steps I, II-1, and II-2 will be described below.
• Step I This step is a step of adding and mixing the aluminum nitride filler of the present invention into an epoxy resin. Through this step, a resin composition can be obtained.
• the epoxy resin may be any of the epoxy resins described above in the section entitled "Resin composition.” In this step, other components described in the above ⁇ Resin composition> other than the compound (A) and the epoxy resin may be added.
• the mixing method is not particularly limited, and examples include a method in which components such as the aluminum nitride filler of the present invention, epoxy resin, resin other than epoxy resin, fillers such as boron nitride, alumina, silica, zinc oxide, and other additives are mixed together or divided into portions and mixed, dissolved, and kneaded using a dispersing/dissolving device such as a grinder, planetary mixer, rotation/revolution mixer, kneader, roll mill, etc., alone or in appropriate combination, and heated as necessary.
• the method for producing a resin composition preferably includes step I.
• Step II-1 This step is a step of obtaining a composition i containing the compound (A) and an epoxy resin, and the composition i is obtained by mixing the compound (A) and the epoxy resin.
• the epoxy resin may be any of the epoxy resins described above in the section entitled "Resin composition.”
• the compound (A) and the other components described in the above ⁇ Resin composition> other than the epoxy resin may be added and mixed to obtain the composition i.
• the mixing method in this step is not particularly limited, and examples thereof include a method in which compound (A), an epoxy resin, a resin other than an epoxy resin, other additives, etc.
• a dispersing/dissolving device such as a grinder, a planetary mixer, a rotation/revolution mixer, a kneader, or a roll mill, either alone or in appropriate combination, and heated as necessary.
• Step II-2 This step is a step of adding and mixing at least one selected from aluminum nitride particles, particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, particles containing an organosilicon compound coating (c) and aluminum nitride particles, and particles containing a silicon-containing oxide coating (b), an organosilicon compound coating (c), and aluminum nitride particles, to composition i.
• a coating (a) can be formed on the surface of the particle.
• the mixing method in this step is not particularly limited, and examples of the method include mixing, dissolving, and kneading the components to be mixed together or divided into portions using a dispersing/dissolving device such as a grinder, a planetary mixer, a rotation/revolution mixer, a kneader, or a roll mill, either alone or in appropriate combination, and heating as necessary.
• a dispersing/dissolving device such as a grinder, a planetary mixer, a rotation/revolution mixer, a kneader, or a roll mill, either alone or in appropriate combination, and heating as necessary.
• the resin composition obtained by step I or the following steps II-1 and II-2 can be formed into a sheet and reacted as necessary to form a heat dissipation sheet.
• the above-mentioned resin composition and heat dissipation sheet can be suitably used for bonding applications such as semiconductor power devices and power modules.
• the manufacturing method of the heat dissipation sheet includes molding the resin composition by a compression press or the like in such a way that both sides are sandwiched between base film, and coating the resin composition on the base film using equipment such as a bar coater, screen printer, blade coater, die coater or comma coater. Furthermore, after molding and coating, the heat dissipation sheet can be subjected to additional processing steps such as a process for removing the solvent, heating to bring it to a B-stage, or complete curing. As mentioned above, various forms of heat dissipation sheets can be obtained depending on the process, making it possible to widely accommodate the target fields of application and methods of use.
• a solvent can be used to improve workability.
• the solvent is not particularly limited, but includes ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; ether-based solvents such as 1,4-dioxane, tetrahydrofuran, and diglyme; glycol ether-based solvents such as methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and diethylene glycol methyl ethyl ether; and other solvents such as benzyl alcohol, N-methylpyrrolidone, ⁇ -butyrolactone, eth
• a high molecular weight component can be added to the resin composition.
• examples include phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, (meth)acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin, acrylic rubber, etc., and among these, from the viewpoint of excellent heat resistance and film formability, phenoxy resin, polyimide resin, (meth)acrylic resin, acrylic rubber, cyanate ester resin, polycarbodiimide resin, etc. are preferred, and phenoxy resin, polyimide resin, (meth)acrylic resin, and acrylic rubber are more preferred. They can be used alone or as a mixture or copolymer of two or more kinds.
• the weight average molecular weight of the high molecular weight component is preferably 10,000 or more and 100,000 or less, and more preferably 20,000 or more and 50,000 or less.
• a good sheet shape with good handleability can be maintained by adding a weight average molecular weight component in the range described above.
• the amount of the high molecular weight component added is not particularly limited, but in order to maintain the sheet properties, it is preferably 0.1% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and even more preferably 2% by mass to 10% by mass.
• An addition amount of 0.1% by mass to 20% by mass provides good ease of handling and allows the formation of a good sheet or film.
• the base film used in the manufacture of the heat dissipation sheet is not particularly limited as long as it can withstand the process conditions during manufacture, such as heating and drying, and examples of such films include films made of polyesters having aromatic rings, such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polypropylene films, polyimide films, and polyetherimide films.
• PET polyethylene terephthalate
• PBT polybutylene terephthalate
• polypropylene films polyimide films
• polyetherimide films polyetherimide films.
• the above-mentioned films may be multi-layer films combining two or more types, and may have a surface treated with a release agent such as a silicone-based release agent.
• the thickness of the base film is preferably 10 ⁇ m or more and 100 ⁇ m or less.
• the thickness of the heat dissipation sheet formed on the base film is preferably 20 ⁇ m or more and 500 ⁇ m or less, and more preferably 50 ⁇ m or more and 200 ⁇ m or less. If the thickness of the heat dissipation sheet is 20 ⁇ m or more, a heat dissipation sheet with a uniform composition can be obtained, and if it is 500 ⁇ m or less, good heat dissipation properties can be obtained.
• the weight-average molecular weights of the compound (A) and the surface treatment agent were measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Specifically, the measurement was performed with an accumulation count of 1500 times using an "Autoflex (registered trademark) max" (manufactured by Bruker Japan Co., Ltd.) as a measuring device and a tetrahydrofuran solution containing 1 mol/L of sodium trifluoroacetate as an ionization reagent.
• MALDI-TOF MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
• the amount of compound (A) and the amount of surface treatment agent (g/m 2 ) were determined by dividing the amount of compound (A) used in the examples or the amount of surface treatment agent (g) used in the comparative examples by the BET specific surface area of the particles measured by the BET one-point method using nitrogen adsorption using a specific surface area measuring device (manufactured by Mountec Co., Ltd., product name: Macsorb HM model-1210).
• the adsorption gas used in measuring the specific surface area was a mixed gas of 70 vol. % He and 30 vol. % N 2 .
• the particles referred to herein refer to particles used when forming the coating (a), and refer to aluminum nitride particles, or particles containing a silicon-containing oxide coating (b) and aluminum nitride particles, or particles containing an organosilicon compound coating (c) and aluminum nitride particles, or particles containing a silicon-containing oxide coating (b), an organosilicon compound coating (c), and aluminum nitride particles.
• viscosity The viscosity of the resin composition was measured using a flow tester (manufactured by Shimadzu Corporation, model name: "CFT-EX”) under conditions of a nozzle of ⁇ 2 ⁇ 2 mmL, 30° C., and a load of 25 kg.
• a container volume 300 mL
• a rotation/revolution mixer product name:
• This raw material for pressing was filled into a mold of 30 mm x 30 mm x 0.3 mm, and then both the upper and lower surfaces were sandwiched between 30 ⁇ m thick copper foils, and the sides were sandwiched between 5 mm thick SUS flat plates, and press molded for 30 minutes at 150° C. to prepare a flat plate sample with a solid volume ratio of 60% by volume. A 10 mm x 10 mm size was cut out from this flat plate sample to prepare a measurement sample.
• the thermal diffusivity of the obtained measurement samples was measured using a xenon laser flash thermal diffusivity measurement device (product name: LFA447 NanoFlash, manufactured by NETZSCH Co., Ltd.)
• the thermal diffusivity thus obtained was multiplied by the theoretical values of the specific heat and density of each measurement sample to calculate the thermal conductivity in the thickness direction of the measurement sample.
• Table 1 shows details of the aluminum nitride particles used in the examples and comparative examples
• Table 2 shows details of the compounds used to form the coating and the compounds used to evaluate the adhesive strength.
• alumina particles and epoxy resins used in the examples and comparative examples are as follows.
• Epoxy resin YD-128 Bisphenol A type epoxy resin (product name: YD-128, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
• organosilicon compound (1) trade name: 2,4,6,8-tetramethylcyclotetrasiloxane, manufactured by Tokyo Chemical Industry Co., Ltd.
• the reaction vessel Since hydrogen gas is generated by the reaction, the reaction vessel was evacuated in advance until the oxygen concentration was 8 volume% or less, which is the explosion limit, and then nitrogen gas was flowed into the reaction vessel to return the internal pressure to normal pressure (0.1 MPa). Thereafter, the reaction vessel was heated to 80 ° C. for 7.5 hours, the organosilicon compound (1) was vaporized, and particles coated with the organosilicon compound were obtained. The obtained particles coated with the organosilicon compound were placed in an alumina crucible and heated in air at 700°C for 3 hours to obtain particles X-2 containing aluminum nitride particles and one layer of the silicon-containing oxide coating (b).
• a coating (a) was formed in the same manner as in Example 1, except that particles X-2 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-2.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 1.70 parts by mass per 100 parts by mass of particles X-2 (corresponding to 6.3 ⁇ 10 ⁇ 3 g per m 2 of the surface area of particles X-2).
• a resin composition X-2 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-2 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-2 are shown in Table 3.
• Example 3 (Production of aluminum nitride filler)
• one layer of silicon-containing oxide coating (b) was formed on aluminum nitride particles I, and then a further layer of silicon-containing oxide coating (b) was formed on the surface of the silicon-containing oxide coating (b) by the same procedure, thereby obtaining particles X-3 containing two layers of silicon-containing oxide coating (b).
• a coating (a) was formed in the same manner as in Example 1, except that particles X-3 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-3.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 1.70 parts by mass per 100 parts by mass of particles X-3 (corresponding to 6.3 ⁇ 10 ⁇ 3 g per m 2 of the surface area of particles X-3).
• a resin composition X-3 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-3 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-3 are shown in Table 3.
• Example 4 (Production of aluminum nitride filler) 11.0 g of organic silicone compound (1) was placed in a ⁇ 50 glass petri dish at the bottom of an 8 L SUS pressure vessel. Next, 200 g of aluminum nitride particles I were placed in an aluminum foil tray, and placed on a SUS raised-bottomed lattice at the top of the 8 L SUS pressure vessel. The 8 L pressure vessel was then covered with a lid, and placed in an oven maintained at 80° C. in a sealed state for 10 minutes. After depressurization, the CVD treatment was performed again in an oven maintained at 80° C. in a sealed state for 4.5 hours.
• a coating (a) was formed in the same manner as in Example 1, except that particles X-4 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-4.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 1.70 parts by mass per 100 parts by mass of particles X-4 (corresponding to 6.3 ⁇ 10 ⁇ 3 g per m 2 of the surface area of particles X-4).
• a resin composition X-4 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-4 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-4 are shown in Table 3.
• Example 5 (Production of aluminum nitride filler)
• particles X-2 containing one layer of the silicon-containing oxide coating (b) were obtained.
• an organosilicon compound coating film (c) having a silanol group was formed in the same manner as in Example 4, except that particles X-2 were used instead of aluminum nitride particles I, thereby obtaining particles X-5 containing an organosilicon compound coating film (c).
• a coating (a) was formed in the same manner as in Example 1, except that particles X-5 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-5.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 1.70 parts by mass per 100 parts by mass of particles X-5 (corresponding to 6.3 ⁇ 10 ⁇ 3 g per m 2 of the surface area of particles X-5).
• Resin composition X-5 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-5 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-5 are shown in Table 3.
• Example 6 (Production of aluminum nitride filler)
• particles X-3 containing two layers of the silicon-containing oxide coating (b) were obtained.
• an organosilicon compound coating film (c) having a silanol group was formed in the same manner as in Example 4, except that particles X-3 were used instead of aluminum nitride particles I, thereby obtaining particles X-6 containing an organosilicon compound coating film (c).
• a coating (a) was formed in the same manner as in Example 1, except that particles X-6 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-6.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 1.70 parts by mass per 100 parts by mass of particles X-6 (corresponding to 6.3 ⁇ 10 ⁇ 3 g per m 2 of the surface area of particles X-6).
• Resin composition X-6 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-6 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-6 are shown in Table 3.
• Example 7 (Production of aluminum nitride filler)
• Resin composition X-7 was obtained in the same manner as in Example 1, except that aluminum nitride filler X-7 was used instead of aluminum nitride filler X-1.
• the evaluation results of the physical properties of the resin composition X-7 are shown in Table 3.
• Example 8 (Production of aluminum nitride filler)
• aluminum nitride particles II were used in place of aluminum nitride particles I to obtain particles X-8.
• Example 9 (Production of aluminum nitride filler) Particles X-8 were obtained by the same procedure as in Example 8. Subsequently, an organosilicon compound coating film (c) having a silanol group was formed in the same manner as in Example 4, except that particles X-8 were used instead of aluminum nitride particles I, thereby obtaining particles X-9 containing an organosilicon compound coating film (c). Subsequently, a coating (a) was formed in the same manner as in Example 8, except that particles X-9 were used instead of aluminum nitride particles I, to obtain aluminum nitride filler X-9.
• compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 0.30 parts by mass per 100 parts by mass of particles X-9 (corresponding to 1.2 ⁇ 10 ⁇ 2 g per m 2 of the surface area of particles X-9).
• Resin composition X-9 was obtained in the same manner as in Example 8, except that aluminum nitride filler X-9 was used instead of aluminum nitride filler X-8.
• the evaluation results of the physical properties of the resin composition X-9 are shown in Table 3.
• Example 10 (Production of aluminum nitride filler)
• Resin composition X-10 was obtained in the same manner as in Example 8, except that 17.62 g of aluminum nitride filler X-10 was used instead of aluminum nitride filler X-8, 11.10 g of AA-3, 9.08 g of AKP-30, and 2.16 g of epoxy resin YD-128 were used.
• the evaluation results of the physical properties of the resin composition X-10 are shown in Table 3.
• Example 11 (Production of aluminum nitride filler)
• Resin composition X-11 was obtained in the same manner as in Example 10, except that aluminum nitride filler X-11 was used instead of aluminum nitride filler X-10.
• the evaluation results of the physical properties of the resin composition X-11 are shown in Table 3.
• Example 13 In the same manner as in Example 2, particles X-2 containing one layer of the silicon-containing oxide coating (b) were obtained. Subsequently, resin composition X-13 was obtained in the same manner as in Example 12, except that particles X-2 were used instead of aluminum nitride particles I. Compound a was used in an amount such that the content of coating (a) in the aluminum nitride filler was 0.22 parts by mass per 100 parts by mass of particles X-2 (equivalent to 8.0 ⁇ 10 ⁇ 4 g per m 2 of the surface area of particles X-2). The evaluation results of the physical properties of the resin composition X-13 are shown in Table 3.
• resin compositions Y-6 to Y-11 were obtained in the same manner as in Comparative Example 1, except that aluminum nitride fillers Y-6 to Y-11 were used instead of the aluminum nitride particles I.
• the evaluation results of the physical properties of resin compositions Y-6 to Y-11 are shown in Table 4.
• the evaluation results of the physical properties of the resin composition Y-12 are shown in Table 4.
• Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, Example 8 and Comparative Example 4, and Example 10 and Comparative Example 5, it can be seen that when an aluminum nitride filler contains a coating film (a) containing compound (A), it is possible to suppress an increase in viscosity when mixed with an epoxy resin.
• Comparative Examples 6 to 12 which used Compounds c to h that have a polyethyleneimine skeleton and a polyalkylene oxide chain and are not compounds having a weight average molecular weight of 2,000 or more and 10,000 or less, the viscosity increases when mixed with an epoxy resin.
• Comparative Examples 1 to 11 and Comparative Examples 1 to 11 that the inherent high thermal conductivity of aluminum nitride is not impaired by the coating (a) containing the compound (A).
• the obtained slurry was applied onto a copper foil having a thickness of 12 ⁇ m using an applicator with a coating gap of 350 ⁇ m, and dried at 100° C. for 10 minutes. After that, a copper foil having a thickness of 12 ⁇ m was placed on the applied slurry, and both sides of the applied slurry were sandwiched between 38 ⁇ m polyester sheets to obtain a pre-press sheet. This was pressed at 180° C. for 1 hour at a pressure of 5 MPa for hardening, to obtain a copper-clad board. Next, the polyester sheet was removed, and 10 mm wide PET adhesive masking tape was firmly attached on the copper foil with a gap of 2 to 3 mm.

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