Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
  • C01B21/072—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with aluminium
  • C01B21/0728—After-treatment, e.g. grinding, purification
• • 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
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • 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
  • C08K9/04—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
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
• • 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
  • C09C3/12—Treatment with organosilicon 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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/28—Nitrogen-containing compounds
  • C08K2003/282—Binary compounds of nitrogen with aluminium
• • 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
  • C08K2201/00—Specific properties of additives
  • C08K2201/002—Physical properties
  • C08K2201/003—Additives being defined by their diameter

Definitions

• the present invention relates to a novel hydrophobic aluminum nitride powder, and more particularly to an aluminum nitride powder to which hydrophobicity is imparted by surface treatment with a silane compound.
• heat-dissipating materials used to efficiently dissipate heat generated from devices has increased. There is. Further, further improvement in heat dissipation performance is required.
• heat dissipation materials are arranged in various paths, and the materials and forms of the heat dissipation materials are also diverse. Among them, there are various heat-dissipating resin materials filled with filler powder having high thermal conductivity, and at the same time, there are many types in their forms, so that the demand in the market is increasing.
• Typical examples of the filler having high thermal conductivity include alumina, aluminum nitride, boron nitride, zinc oxide, and magnesium oxide. Further, as a heat-dissipating resin material containing these fillers, a heat-dissipating sheet, a semiconductor encapsulant, a heat-dissipating grease, a heat-dissipating adhesive and the like are known.
• aluminum nitride (AlN) powder has a particularly high thermal conductivity, which is several tens of times or more that of silica and five times or more that of alumina, and is therefore highly expected as a heat dissipation filler. ing. Further, since high insulating properties are required for electronic device applications, a filler that is chemically stable and does not release ionic impurities is required as a filler to be filled in the resin.
• AlN powder has high insulating properties, it is easily hydrolyzed to generate ammonium ions when it comes into contact with water, so that a molded product composed of a resin composition filled with the hydrolyzed particles has high insulating properties. Its use was restricted in applications that required sex. That is, water infiltrates into the molded body (including AlN resin) in contact with water or in a high humidity atmosphere, and the contact with AlN in the molded body causes hydrolysis.
• Patent Document 1 proposes an AlN powder that has been surface-treated with orthoric acid to impart water resistance.
• phosphorus compounds may elute phosphate ions and are avoided in electronic materials that require high insulation.
• the epoxy resin often contains an alkaline curing agent such as amine. Therefore, when the AlN powder surface-treated with orthoric acid is blended with the epoxy resin, the alkaline curing agent reacts with the phosphoric acid group, and as a result, the film of the aluminum nitride compound formed on the surface of the AlN particles is formed. It is lost, and there arises a problem that the water resistance of AlN existing in the epoxy resin deteriorates.
• Patent Document 2 proposes to improve the moisture resistance by forming a silicon oxide coating layer on the AlN surface. That is, by forming a coating layer of silicon oxide on the surface, hydrolysis due to contact between AlN and water is suppressed.
• silicon oxide has low thermal conductivity, which not only lowers the thermal conductivity of AlN, but also tends to generate aggregated particles in the surface treatment step of coating the silicon oxide, which deteriorates the filling property into the resin. There is a risk.
• Patent Document 3 shows that the water resistance at room temperature is improved by surface-treating the AlN powder with a hydrophobic agent made of an organosilane having a long-chain alkyl group having 9 to 15 carbon atoms. ..
• a hydrophobic agent made of an organosilane having a long-chain alkyl group having 9 to 15 carbon atoms. ..
• the AlN powder treated with such a hydrophobic agent having a strongly hydrophobic group having a long-chain alkyl chain exhibits extremely high hydrophobicity, the water resistance in the resin is not sufficient. That is, when this powder is filled in the resin, the hydrolysis of the AlN powder (that is, the hydrolysis in the resin) due to the permeation of water into the resin cannot be sufficiently prevented, and there is room for further improvement. rice field.
• Patent Document 4 proposes an aluminum nitride powder surface-treated with an alkoxy-modified silicone
• Patent Document 5 describes a reaction product with a silane coupling agent or a titanium coupling agent. Ceramic powders coated with certain organic compounds have been proposed.
• the aluminum nitride powder surface-treated with the alkoxy-modified silicone of Patent Document 4 has high water resistance (hydrolysis resistance) in the powder state, it is water resistant in the state of being blended with the resin as in Patent Document 3. It cannot be said that the sex is sufficient, and improvement is needed. Further, the same applies to the case where the surface treatment technique of Patent Document 5 is applied to the aluminum nitride powder, and the water resistance in the state of being blended in the resin is not sufficient.
• the above problem is particularly problematic in aluminum nitride powder composed of particles having a relatively small particle size.
• an object of the present invention is that when the resin is filled, the hydrolysis of aluminum nitride due to contact with water infiltrated into the resin is highly suppressed, and hydrophobic nitride capable of exhibiting high water resistance characteristics can be exhibited.
• the purpose is to provide aluminum powder.
• the present inventors when the aluminum nitride (AlN) powder is filled in the resin, the hydrolysis of AlN by contact with water permeated into the resin is carried out. It was found that a gap is generated at the interface between the particles of the AlN powder and the resin, and the water that has penetrated into the resin accumulates in the gap and rapidly progresses. Further, it was found that when the AlN powder is excessively hydrophobized with a hydrophobizing agent in order to improve the water resistance, the affinity with the resin is lowered, the generation of the gap is promoted, and the hydrolysis of AlN proceeds. Also got.
• AlN aluminum nitride
• AlN powder which has been given a certain level of hydrophobicity by surface treatment with a hydrophobic agent, exhibits hydrophobicity and an appropriate affinity with the resin, and is contained in the resin. We have found that hydrolysis by permeated water can be effectively suppressed, and have completed the present invention.
• hydrophobic aluminum nitride powder having a degree of hydrophobicity of 1 to 45.
• the hydrophobic aluminum nitride powder of the present invention can preferably take the following aspects.
• the molecular weight of the silane compound is 400 or less.
• the degree of hydrophobicity is in the range of 1 to 30.
• the cumulative volume 50% particle size D 50 is 0.5 to 20 ⁇ m.
• the decomposition rate of the aluminum nitride measured after immersing the test piece in 50 g of ion-exchanged water at 120 ° C. for 90 hours (hereinafter, may be referred to as a basic hydrolysis rate in a resin) is 25% or less. To be.
• a resin composition containing the above-mentioned hydrophobic aluminum nitride powder.
• the hydrophobic aluminum nitride powder is contained in an amount of 10 to 1500 parts by mass per 100 parts by mass of the resin.
• the resin is an epoxy resin or a (meth) acrylic resin. Is preferable.
• Step of preparing non-hydrophobic aluminum nitride powder as raw material powder The surface of the raw material powder is obtained by mixing the raw material powder and the silane compound so that the degree of hydrophobicity is 1 to 45 and the carbon content derived from the silane compound is in the range of 0.1 to 0.5% by mass.
• Surface treatment process to perform treatment A method for producing a hydrophobic aluminum nitride powder containing the above is provided. In such a production method, it is desirable that the molecular weight of the silane compound is 400 or less.
• the hydrophobic aluminum nitride powder of the present invention is surface-treated using a silane compound as a hydrophobic agent, and has a degree of hydrophobicity in the range of 1 to 45, and at the same time, a hydrophobic agent introduced into the particle surface.
• the carbon content derived from (silane compound) is in the range of 0.1 to 0.5% by mass.
• the hydrolyzability (basic hydrolysis rate in the resin) of the AlN powder in an epoxy resin molded product containing a predetermined amount of the hydrophobic aluminum nitride powder is determined. When measured, it shows a value of 25% or less (see Examples for detailed measurement conditions). That is, the hydrophobic AlN powder of the present invention having the above-mentioned degree of hydrophobization and carbon content derived from the hydrophobizing agent has an affinity for the resin because carbon derived from the hydrophobizing agent is present on the particle surface in a certain ratio. As a result, it is present in close contact with the resin component in various resin molded bodies, and exhibits high hydrolysis resistance (water resistance) even in the resin molded bodies.
• the hydrophobic AlN powder of the present invention having the above-mentioned degree of hydrophobicity and carbon content has a high affinity for the polymer chain (substantially a hydrocarbon chain) forming the resin. It is presumed that there is.
• the hydrophobic aluminum nitride powder of the present invention is extremely useful as a filler to be blended in a resin composition for a heat-dissipating material that requires high reliability under high humidity conditions.
• the hydrophobic aluminum nitride powder of the present invention comprises AlN particles surface-treated with a silane compound. That is, the silane compound forms a chemical bond with a hydroxyl group or the like existing on the surface (or an oxide film formed on the surface) of the aluminum nitride particles and bonds to the surface thereof, thereby exhibiting hydrophobicity and exhibiting hydrophobicity. It suppresses the hydrolysis of aluminum nitride (AlN).
• the surface treatment with the silane compound as described above imparts hydrophobicity, and the degree of hydrophobicity is in the range of 1 to 45, preferably 1 to 30.
• This degree of hydrophobicity is also called methanol wettability, and is a parameter measured by a method that utilizes the fact that hydrophobic aluminum nitride powder floats in water but is completely suspended in methanol and settles. Specifically, 100 cc of methanol aqueous solution having different methanol concentrations in 1% by mass increments is placed in a beaker having a capacity of 200 cc. When 1 g of the sample AlN powder was added to each aqueous solution (beaker) and the aqueous solution in the beaker was stirred with a magnetic stirrer for 5 minutes and 50% of the AlN powder was suspended and settled, the aqueous solution in the beaker was used. The value of the volume percentage of methanol is defined as the degree of hydrophobicity. AlN powder with low hydrophobicity does not suspend and settle unless it is an aqueous solution with a high methanol concentration.
• the hydrophobic AlN powder of the present invention has a carbon content derived from a silane compound (hydrophobicizing agent) present on the particle surface in the range of 0.1 to 0.5% by mass.
• the carbon content is a value measured by a carbon analyzer after the hydrophobization treatment (after the surface treatment) and calculated by the following formula.
• Carbon content (% by mass) derived from silane compound A ⁇ 100 / B
• A Carbon amount after hydrophobization treatment
• B Total mass of AlN powder after hydrophobization treatment
• the carbon content before hydrophobization treatment is substantially zero, or even if it is not zero, it is an impurity level and is ignored. It is a numerical value that can be done. Therefore, the carbon content before the hydrophobization treatment may be treated as zero, and the carbon content per total mass of the AlN powder after the hydrophobization treatment may be treated as the carbon content derived from the silane compound.
• the water resistance (hydrolysis resistance) as a powder is improved, but the water resistance in the resin is unsatisfactory, and there are many aggregated particles.
• the filling property for resin is also low.
• the above-mentioned degree of hydrophobicity is satisfied and the carbon content satisfies the above-mentioned range (0.1 to 0.5% by mass)
• not only the water resistance as a powder is high, but also the water resistance in the resin is high.
• the filling property for resin is high.
• the hydrophobic AlN powder has very high hydrolysis resistance (water resistance in the resin) to the moisture permeated into the molded body. High.
• the decomposition rate of the AlN powder (basic water addition in the resin) when an epoxy resin molded body ( ⁇ : 10 mm ⁇ 1.2 mm thickness) containing 25% by mass of hydrophobic AlN powder is immersed in 50 g of ion-exchanged water for 90 hours.
• Decomposition rate is extremely low at 25% or less. That is, in the hydrophobic AlN powder of the present invention satisfying the above-mentioned degree of hydrophobicity and carbon content, since hydrocarbon molecules having an appropriate size are distributed in an appropriate amount on the particle surface, a resin is formed.
• the affinity for the polymer chains is greatly improved, and as a result, the particles forming the AlN powder and the resin are in close contact with each other, the permeation of water is effectively suppressed, and the water resistance in the resin is extremely high. It's getting higher. Therefore, as shown in Examples described later, even if the compounding composition of the epoxy resin molded product is changed or the resin type is changed to acrylic resin and the hydrolyzability is measured in the same manner, the decomposition is similarly low. Show sex. Of course, the hydrophobic AlN powder of the present invention has extremely low water resistance (hydrolyzability) as a powder.
• the carbon content derived from the silane compound is approximately proportional to the density of the silane compound bonded to the particle surface. Therefore, the hydrophobic group density of the silane compound represents a suitable surface treatment amount of the silane compound. You can also do it.
• the hydrophobic AlN powder of the present invention has a hydrophobic group density indicating the number of silane compounds in the range of 0.5 to 5.0 pieces / nm 2 , preferably 1.0 to 4.0 pieces / nm 2 . It is preferable to have. This hydrophobic group density can be calculated from the above-mentioned carbon content, or can be measured by 29 SiNMR.
• the silane compound (hydrophobicizing agent) that satisfies the above-mentioned degree of hydrophobicity and carbon content (hydrophobic group density) is a silane compound having a relatively low hydrophobicity effect, for example, an appropriate size.
• Those having a hydrocarbon group can be used alone or in combination of two or more.
• the reaction rate can be increased and the silane compound density (Si density) can be increased. Therefore, a silane compound having an alkyl group or an alkylene group having a molecular weight of 400 or less or a carbon number of 8 or less is particularly suitable.
• the surface-treated AlN powder surface-treated with a silane compound a part or all of the silane compound is bonded to the particle surface by a dehydration condensation reaction with a hydroxyl group of an aluminum oxide layer present not a little on the surface of the AlN particles. exist.
• the AlN powder surface-treated in this way is dispersed in an organic solvent, and even after solid-liquid separation, a certain amount of silane is not washed away and exists in a powdered state.
• the free silane compound not bonded to the surface of the AlN particles is usually removed by washing with an organic solvent, heat treatment under reduced pressure, or the like.
• Typical examples of the above silane compound are a silane compound having a reactive functional group and a silane compound having no reactive functional group.
• silane compound having a reactive functional group examples include the following alkoxysilanes. 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-Acryloxypropyltrimethoxysilane, 3-Mercaptopropyltrimethoxysilane, 3-Aminopropyltrimethoxysilane, 3-Aminopropyltriethoxysilane, 2-Aminoethyl-3-amino
• silane compound having no reactive functional group examples include the following alkylalkoxysilanes and arylalkoxysilanes.
• chlorosilane compounds can also be used.
• the hydrophobic AlN powder of the present invention has a relatively low degree of hydrophobicity, and the AlN powder having a low degree of hydrophobicity has an extremely low value for the basic hydrolysis rate in the resin, which is an evaluation value of water resistance using an epoxy resin. What is shown is that conventional hydrophobization techniques cannot be predicted. That is, it is considered that the surface treatment of AlN powder with a silane compound (hydrophobicizing agent) has higher water resistance even in the resin as the degree of hydrophobization indicating the degree of hydrophobization is higher.
• the property is dominated by the adhesion between the resin and the particles, and the resin of the surface-treated AlN powder (having a high degree of hydrophobicity exceeding 50) treated with the silane compound having a strongly hydrophobic group.
• the internal basic hydrolysis decomposition rate is not necessarily low and exceeds 25%.
• the surface-treated aluminum nitride powder of the present invention has a cumulative volume of 50% particle size D 50 of 0.3 to 20 ⁇ m, preferably 0, in a particle size distribution measured by a laser diffraction scattering type particle size distribution meter using an ethanol solvent. It is preferably .5 to 8 ⁇ m. That is, the hydrophobic AlN powder having such a small particle size is a particle having a relatively large specific surface area when used as a filler, and has a large area forming an interface with a resin, so that the effect of the present invention is particularly effective. It appears prominently.
• the hydrophobic AlN powder of the present invention preferably has a cumulative volume of 90% particle size D 90 of 100 ⁇ m or less, preferably 20 ⁇ m or less.
• the surface-treated aluminum nitride powder of the present invention preferably has a BET specific surface area A in the range of 0.1 to 6.0 m 2 / g measured by the nitrogen adsorption one-point method.
• the hydrophobic AlN powder of the present invention is produced, for example, through the following steps.
• the raw material powder and the silane compound are mixed to have a degree of hydrophobicity of 1 to 45, particularly 1 to 30, and a carbon content derived from the silane compound of 0.1 to 0.5% by mass (or hydrophobicity derived from the silane compound).
• the AlN powder produced by a conventionally known method can be used without particular limitation.
• it may be an AlN powder produced by a direct nitriding method, a reduction nitriding method, a gas phase synthesis method, or the like.
• the amount of aggregates contained in the raw material powder is small regardless of the particle size distribution or the size of the average particle size.
• the agglomerates remain in the surface-treated hydrophobic AlN as they are, and tend to cause deterioration of the filling property to the resin. Further, the voids contained in the aggregate remain even after being filled in the resin molded product, and are easily hydrolyzed by the infiltrated water.
• the inside of the aggregate is difficult to be surface-treated, if the aggregate is crushed after the surface treatment step, the untreated surface that has not been surface-treated is exposed, so that the untreated surface is susceptible to hydrolysis and becomes a resin. I'm not familiar with it. Therefore, before the surface treatment step, it is preferable to crush it with a ball mill, a jet mill or the like, or remove it from the raw material powder by dry classification or wet classification, if necessary.
• the particle size distribution of the non-hydrophobic AlN powder as a raw material is not particularly limited, and may be appropriately determined in consideration of the change in the particle size due to the surface treatment of the target hydrophobic AlN powder.
• the cumulative volume 50% particle size D50 is in the range of 20 ⁇ m or less.
• the specific surface area of the raw material powder measured by the BET method is 0.6 m 2 / g or more.
• the non-hydrophobic AlN powder contains impurities derived from raw materials used for the synthesis of AlN or impurities such as alkaline earth elements and rare earth elements added in the synthesis process up to about 5% by mass. It doesn't matter if it is. Further, boron nitride may be contained as an impurity derived from an antiaggregating agent or a setter up to about 5% by mass. However, the amount of impurities that significantly reduces the crystallinity of AlN is not preferable because it causes a decrease in thermal conductivity.
• the aluminum nitride content in the raw material powder is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 99% by mass or more.
• the hydrophobic AlN powder of the present invention binds a silane compound which is a hydrophobic agent to the surface of aluminum nitride particles at high density
• the non-hydrophobic AlN powder which is a raw material to be used for surface treatment has many oxide layers on the surface.
• the oxide layer reduces the thermal conductivity of the AlN powder. Therefore, it is preferable that the oxide layer on the surface of the particles is limited to an amount that does not significantly reduce the thermal conductivity. For example, when the thickness of the oxide layer is about 0.005% to 0.2% of the diameter of the particles, the density of hydroxyl groups capable of reacting with the silane compound in the oxide layer is 0.8 pieces / nm 2 or more. It becomes.
• the density of hydroxyl groups in the AlN powder is 0.8 to 2 / nm 2 , and in particular, 0.9 to 1.6 / nm 2 . It is preferable to do so.
• the particles that have undergone excessive oxidation treatment with a hydroxyl group density of more than 2 / nm 2 are in a state where the oxidation reaction has proceeded excessively or hydrolysis has progressed to aluminum hydroxide. It may be in a state of alteration. Such a state is not preferable because the surface has low thermal conductivity.
• this oxide layer may be formed by natural oxidation when the AlN powder (non-hydrophobic AlN powder) is stored, or may be formed by a conscious oxidation treatment step. Further, the oxidation treatment of the AlN powder may be performed in the process of producing aluminum nitride, or may be performed as a separate step after the aluminum nitride is produced. For example, the non-hydrophobic AlN powder obtained by the reduction nitriding method undergoes an oxidation treatment step in the manufacturing process for the purpose of removing carbon used in the reaction, so that an aluminum oxide layer is present on the surface. An oxidation treatment step may be further added to the aluminum nitride powder of the reduction nitriding method thus obtained.
• the suitable conditions are as follows.
• the non-hydrophobic AlN powder (raw material powder) obtained by various methods is preferably used in an oxygen-containing atmosphere at a temperature of preferably 400 to 1,000 ° C, more preferably 600 to 900 ° C, and preferably 10 to 600.
• An aluminum oxide layer can be formed on the surface of AlN particles by heating for a minute, more preferably 30 to 300 minutes.
• oxygen-containing atmosphere for example, oxygen, air, water vapor, carbon dioxide and the like can be used, but in relation to the object of the present invention, treatment in air, particularly under atmospheric pressure is preferable.
• the oxidation treatment is performed at a high temperature exceeding 1000 ° C. for a long time, a thick oxide film may be formed on the surface of the AlN particles, and this aluminum oxide film is uniform because the thermal expansion coefficient is different from that of the AlN core.
• the film cannot be maintained, the film may crack, and the AlN surface of the core may be exposed, which causes the hydrolysis resistance to deteriorate. Therefore, the oxidation treatment conditions should not be too strict.
• the shape of the primary particles of the non-hydrophobic AlN powder which is the raw material powder in the present invention, is not particularly limited, and may be any shape such as an indefinite shape, a spherical shape, a polyhedral shape, a columnar shape, a whiskers shape, and a flat plate shape. can. Above all, for filler applications, a spherical shape having good viscosity characteristics and high reproducibility of thermal conductivity is desirable. Further, it is preferable that the particle aspect ratio is small. A suitable aspect ratio is 1 to 3.
• the above-mentioned raw material powder (non-hydrophobic AlN powder) is surface-treated with a silane compound, whereby the desired hydrophobic AlN powder of the present invention can be obtained.
• the degree of hydrophobicity is 1 to 45, particularly 1 to 30, and the carbon content derived from the silane compound is 0.1 to 0.5% by mass (or derived from the silane compound).
• the hydrophobic group density is 0.5 to 5.0 elements / nm 2 , especially 1.0 to 4.0 elements / nm 2 ). Therefore, the amount of the silane compound varies depending on the type of the silane compound, the amount of OH groups present on the particle surface of the non-hydrophobic AlN powder to be subjected to surface treatment, and the specific surface area of the non-hydrophobic AlN powder, but is generally used.
• the silane compound is used in an amount of 0.1 to 5 parts by mass, preferably 0.2 to 1.0 part by mass with respect to 100 parts by mass of the aluminum nitride powder having an oxide layer on the surface.
• the method of contacting the hydrophobic AlN powder with the silane compound may be either a dry surface treatment or a wet surface treatment.
• Dry surface treatment is a method of mixing aluminum nitride powder and a hydrophobic agent by dry mixing without using a large amount of solvent.
• the dry mixing method includes the following methods. A method of gasifying a silane compound and mixing it with the raw material powder; A method of spraying or dropping a liquid silane compound and mixing it with the raw material powder; A method of diluting a silane compound with a small amount of organic solvent to increase the amount of liquid, and then spraying or dropping;
• the method of gasification can be applied when treating a highly volatile low molecular weight silane compound or the like.
• the method of diluting with an organic solvent is performed when the amount of silane compound is too small to uniformly disperse in the entire powder, but if too much organic solvent is used for dilution, the liquid content of the entire powder is high. Will increase and cause aggregation.
• diluting it is desirable to dilute about 5 to 50 times by weight. In any case, in the dry method, it is important to evenly distribute the silane compound throughout the raw material powder.
• the silane compound When mixing by dry type, it may be heated while heating, or it may be heated separately after sufficiently mixing at room temperature. It is desirable to carry out heating as a method for strongly immobilizing the silane compound on the surface of AlN particles. However, if heated at an excessively high temperature, the silane compound may volatilize, or the condensation between the silane compounds may proceed excessively, resulting in uneven treatment. Further, if the mixing time at room temperature is provided before the start of heating, the reaction will occur after the silane compound has spread throughout, and a uniform treated powder can be easily obtained.
• the heating temperature during or after mixing is preferably 20 to 150 ° C, particularly preferably about 40 to 130 ° C.
• the silane compound can also be subjected to surface treatment after being hydrolyzed with an acid, a base or the like in advance.
• the acids and bases used for hydrolysis, especially basic substances change the surface of AlN particles, so it is better to avoid using them.
• a general mixing / stirring device such as a planetary mixer, a Henschel mixer, a super mixer, a V-type mixer, a drum mixer, a double cone mixer, and a locking mixer can be used. It is desirable that these devices are provided with a heating function. By heating while stirring, the number of surface treatment steps can be reduced. In addition, since powders tend to aggregate in drywall mixing, it is desirable that the mixing device be equipped with a mechanism such as a crushing blade or a chopper to disassemble the once generated aggregates.
• the powder may be pressed against the wall of the mixing vessel to form a thick adhesion layer, and in that case, the powder is in a mixed state. Can no longer be maintained. Therefore, it is even better to equip the wall surface of the mixing container with measures to prevent adhesion such as a fluororesin coat, a mechanism for removing adhered powder such as a knocker, and a scraping mechanism with a devised stirring blade.
• the wet surface treatment is a method in which a solvent is used when the aluminum nitride powder and the silane compound are mixed.
• the hydrophobizing agent can be uniformly distributed to all the particles, so that the treatment agent has less unevenness and the powder properties are stable.
• a drying step is required, and the silane compound may segregate depending on the drying method.
• addition of the silane compound to the solvent, dispersion of the raw material AlN powder in the solvent, and heating, solvent removal, and heat drying are performed as necessary.
• the heating performed as necessary is for the purpose of promoting the reaction between the silane compound and the surface of the AlN particles.
• the heating temperature is preferably about 50 to 120 ° C., and the time is preferably about 60 to 300 minutes. Further, as in the dry surface treatment, heating may be performed after removing the solvent in order to immobilize the silane compound on the surface of AlN particles.
• the heating temperature is preferably 20 to 150 ° C, particularly preferably about 40 to 130 ° C.
• heating may be performed under reduced pressure.
• the pressure at the time of depressurization is preferably 10 hPa or less.
• the obtained hydrophobic AlN powder may be aggregated, and the powder characteristics and the filling property into the resin may be impaired. In that case, it is preferable to remove coarse particles by a crushing treatment or a classification treatment.
• the above crushing treatment and classification treatment are preferably performed so that the cumulative volume 90% particle size D 90 of the hydrophobic AlN powder is 100 ⁇ m or less.
• the crushing device include a dry crushing device such as a stone mill type grinder, a raft machine, a cutter mill, a hammer mill, and a pin mill. Among them, a stone mill type grinder that can selectively crush large aggregates in a short time and has less uneven crushing is preferable.
• the atmosphere of the crushing treatment is preferably in the air or in an inert gas. Further, the humidity of the atmosphere is preferably not too high, specifically, the humidity is less than 70%, more preferably less than 55%.
• a dry classification method or a wet classification method can be selected, but if high-precision classification is not required, a dry classification method that can omit the solvent removal step is desirable.
• a dry classification method an air flow classification or a vibrating sieve can be used.
• the airflow classification method or apparatus may be appropriately selected so as to have a particle size distribution suitable as a filler for blending with the resin.
• the airflow classification method is a method in which the powder is dispersed in the airflow and separated into fine powder and coarse powder by the gravity, inertial force, and centrifugal force of the particles at that time.
• the accuracy suitable for classifying particles of several ⁇ m can be obtained by a classifying device using inertial force and centrifugal force.
• an impactor that separates fine powder and coarse powder when bending a powder or granular material that has gained momentum with an air flow into a curve.
• examples include a semi-free vortex centrifugal type that classifies particles by applying centrifugal force to the particles, and a Coanda type that utilizes the Coanda effect.
• Examples of the classification device using the inertial force include a cascade impactor, a viable impactor, an aerofine classifier, an eddy classifier, an elbow jet, and a hyperplex.
• the method using centrifugal force separates fine powder and coarse powder using a vortex air flow
• examples of the device include a free vortex type and a forced vortex type.
• Free vortex type devices include cyclones without guide blades, multi-stage cyclones, turboplexes that use secondary air to promote the elimination of aggregation, dispersion separators with guide blades to improve classification accuracy, microspins, and microcuts. Be done.
• the forced vortex type is a device that enhances the classification accuracy by applying centrifugal force to the particles with a rotating body inside the device and creating another air flow inside the device, such as turbo classifier and donacerec.
• the crushing treatment and the classification treatment may be used in combination.
• the surface treatment with the above-mentioned silane compound not only appropriately improves the hydrophobicity of the AlN powder and improves the water resistance of the powder itself, but also adheres the resin to the AlN particles when blended with the resin. By improving the properties, the AlN particles in the resin molded body are less likely to be hydrolyzed.
• the hydrophobic AlN powder of the present invention exhibits excellent water resistance when filled in a resin to form a resin composition.
• Thermosetting resin and thermoplastic resin are used without limitation as the resin used for the composition of such a resin composition, but particularly for a resin having a property that water easily penetrates into the resin matrix.
• the hydrophobic AlN powder of the present invention is effective.
• the hydrophobic AlN powder of the present invention can be used in a ratio of 10 to 1500 parts by mass with respect to 100 parts by mass of the resin.
• the amount of the hydrophobic AlN powder is 10 to 700 parts by mass, and the other It is preferable to form a resin composition in combination with a filler.
• thermosetting resin examples include phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, diallyl phthalate resin, polyurethane resin, silicone resin and the like.
• thermoplastic resin Vinyl polymerized resins such as acrylic resin and polystyrene; polyamide; Nylon; Polyacetal; Polycarbonate; Polyphenylene ether, Polyester such as polyethylene terephthalate; Cyclic polyolefin; Polyphenylene sulfide; Polytetrafluoroethylene; Polysulfone; Liquid crystal polymer; Polyetheretherketone; Thermoplastic polyimide polyamide-imide;
• epoxy resins and (meth) acrylic resins are preferable in consideration of compatibility with resins that are generally used as heat-dissipating materials. Further, these have an advantage that they can be easily cured by heating or light irradiation when the production method described later is adopted. These resins may be used alone or in combination.
• the epoxy resin and (meth) acrylic resin suitable for use will be described below.
• the epoxy resin that can be used in the present invention is not particularly limited, and general ones can be used. Specific examples are as follows. Bisphenol A type epoxy resin; Bisphenol F type epoxy resin; Phenolic novolac type epoxy resin; Cresol novolac type epoxy resin; Alicyclic epoxy resin; Heterocyclic epoxy resin; Glycidyl ester type epoxy resin; Glycidylamine type epoxy resin; Biphenyl type epoxy resin; Epoxy resin containing naphthalene ring; Cyclopentadiene-containing epoxy resin Among the above, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin are preferable.
• a general curing agent for the epoxy resin can be used.
• Thermo-curable curing agents such as amines, polyamides, imidazoles, acid anhydrides, boron trifluoride-amine complexes, dicyandiamides, organic acid hydrazides, phenol novolac resins, bisphenol novolak resins, cresol novolak resins, etc.; Photo-curing agents such as diphenyliodonium hexafluorophosphate, triphenylsulfonium hexafluorophosphate, etc .; Among these, amines, imidazoles, and acid anhydrides are preferable.
• amine curing agent examples include the following amine compounds.
• Chain aliphatic amines for example Diethylenetriamine, Triethylenetetramine, Tetraethylenepentamine, Dipropylene diamine, Diethylaminopropylamine; Cyclic aliphatic amines, for example N-Aminoethylpiperazine, Isophorone diamine; Cyclic aromatic polyamines, eg, m-xylene diamine; Aromatic amines, for example Meta-phenylenediamine, Diaminodiphenylmethane, Diaminodiphenyl sulfone;
• imidazole curing agent examples include the following imidazole compounds. 2-Methylimidazole; 2-Ethyl-4-methylimidazole; 1-Cyanoethyl-2-undecylimidazole trimellitate; Epoxy imidazole adduct;
• Examples of the acid anhydride curing agent include the following acid anhydride compounds. Phthalic anhydride; Trimellitic acid anhydride; Anhydrous pyromellitic acid; Anhydrous benzophenone tetracarboxylic acid; Ethylene glycol bistrimeritate; maleic anhydride; Tetrahydrophthalic anhydride; Methyltetrahydrophthalic anhydride; Methylendomethylene tetrahydrophthalic anhydride; Methylbutenyltetrahydrophthalic anhydride; Dodecenyl succinic anhydride; Hexahydrophthalic anhydride; Succinic anhydride; Methylcyclohexene dicarboxylic acid anhydride; Alkylstyrene-maleic anhydride copolymer; Chlorendic acid anhydride; Polyacelaic acid anhydride;
• a curing accelerator may be added and cured if necessary.
• the following compounds can be exemplified as specific examples of the curing accelerator.
• Imidazole-based curing accelerators such as imidazole, 2-methylimidazole; Phosphine derivatives such as triphenylphosphine, tris-p-methoxyphenylphosphine, tricyclohexylphosphine; Cycloamidine derivatives such as 1,8-diazabicyclo (5.4.0) undec-7-ene;
• a reactive diluent having an epoxy group may be further blended.
• the reactive diluent can also be a general one.
• the following compounds can be exemplified as specific examples of the reaction diluent.
• the (meth) acrylic resin that can be used in the present invention is not particularly limited, and general ones can be used.
• the following compounds can be exemplified as examples of the monofunctional monomer used for forming the (meth) acrylic resin.
• the following compounds can be exemplified as examples of the polyfunctional monomer used for forming the (meth) acrylic resin.
• the above polyfunctional monomer can be used alone to form a (meth) acrylic resin, or can be mixed with a monofunctional monomer and used to form a (meth) acrylic resin.
• a thermal radical polymerization initiator can be used to polymerize and cure the (meth) acrylic monomer described above.
• the following compounds can be exemplified as examples of the thermal radical polymerization initiator.
• Organic peroxides for example Octanoyl peroxide, Lauroyl peroxide, t-Butylperoxy-2-ethylhexanoate, Benzoyl peroxide, t-Butyl peroxyisobutyrate, t-Butyl peroxylaurate, t-hexyl peroxybenzoate, Di-t-butyl peroxide;
• Azobis-based polymerization initiator for example 2,2-Azobisisobutyronitrile, 2,2-Azobis- (2,4-dimelvaleronitrile);
• benzoyl peroxide, t-butylperoxy-2-ethylhexanoate and the like can be preferably used when polymerizing at
• a known initiator can be adopted as the photopolymerization initiator of the (meth) acrylic group.
• the hydrophobic AlN powder of the present invention When used as a filler, other fillers may be contained. Such a filler does not necessarily have to be a thermally conductive filler, and may be combined with a filler having a low thermal conductivity if improvement in filling property can be expected.
• the combined use with the above other fillers is useful for improving the filling property of the hydrophobic AlN powder when the particle size is small, and in particular, the D 50 has a particularly small particle size such as 0.5 to 8 ⁇ m. It is suitable when using the hydrophobic AlN powder of.
• the particle size of the other filler is preferably 15 to 100 ⁇ m for D50 , and the other filler is used in the range of 150 to 900 parts by mass with respect to 100 parts by mass of the hydrophobic AlN powder. It is preferable to do so.
• the filler which will be described later, aluminum oxide is particularly preferable.
• the heat conductive filler include aluminum oxide, boron nitride, ZnO, MgO, carbon fiber, diamond particles and the like.
• composite oxides such as silica, quartz, talc, mica, silica-titania, silica-zirconia, silica-valium oxide, silica-aluminum, silica-calcia, silica-strontium oxide, silica-magnesia, zeolite, montmorillonite and the like.
• Silicates and the like can also be used as a heat conductive filler.
• the above filler may or may not be surface-treated.
• an additive known per se may be contained in addition to the filler and the resin raw material.
• the purpose of adding the additive is to improve the filling property of the filler and to improve the mechanical properties of the resin molded product.
• Such additives can be used without particular limitation as long as they have properties that do not inhibit the adhesion between the hydrophobic AlN powder and the resin and those that do not inhibit thermal conductivity.
• an organic solvent may be used as long as it is removed in the process of molding into the final resin molded product.
• a silane compound can be particularly preferably used from the viewpoint of affinity with hydrophobic AlN and other general fillers.
• the silane compound is preferably blended in a ratio of 0.01 to 5 parts by mass with respect to 100 parts by mass of the resin.
• Specific examples of the silane compound used as an additive are as follows.
• Epoxy group-containing silanes eg 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-Epoxycyclohexyl) ethyltrimethoxysilane;
• Methacrylic group-containing silanes such as 3-methacryloxypropyltrimethoxysilane, 3-Acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane;
• Amino group-containing silanes such as 3-Aminopropyltrimethoxysilane, 3-Aminopropyltriethoxysilane, 2-Aminoethyl-3-amin
• the resin composition composed of the hydrophobic AlN powder and the resin of the present invention can be suitably used as a heat-dissipating resin material.
• the heat-dissipating resin material produced by using the hydrophobic AlN powder of the present invention is used as a heat-dissipating member for efficiently dissipating heat generated from semiconductor parts mounted on, for example, home appliances, automobiles, notebook personal computers, and the like.
• Materials can be mentioned. Specific examples of these include heat-dissipating grease, heat-dissipating gel, heat-dissipating sheet, phase change sheet, adhesive and the like.
• the composite material can also be used as an insulating layer used for, for example, a metal base substrate, a printed circuit board, a flexible substrate, a semiconductor encapsulant, an underfill, a housing, a heat dissipation fin, and the like.
• [Raw material AlN powder] -A1 H No. produced by the reduction nitriding method manufactured by Tokuyama Corporation. 1 grade powder.
• ⁇ D 50 1.20 ⁇ m ⁇ Specific surface area 2.60m 2 / g ⁇ Oxygen concentration 0.8% by mass ⁇ Surface hydroxyl group amount 1.4 pieces / nm 2 -A2: HF-05 grade powder produced by the reduction nitriding method manufactured by Tokuyama Corporation.
• ⁇ D 50 4.95 ⁇ m ⁇ Specific surface area 0.80m 2 / g ⁇ Oxygen concentration 0.8% by mass ⁇ Surface hydroxyl group amount 1.3 / nm 2 -A3: AlN powder produced by the direct nitriding method.
• ⁇ D 50 1.18 ⁇ m ⁇ Specific surface area 2.72m 2 / g ⁇ Oxygen concentration 0.5% by mass ⁇ Surface hydroxyl group amount 0.3 / nm 2
• AlN powder [Aluminum oxide] Showa Denko A20s (average particle size 22.7 ⁇ m) was used as the aluminum oxide filler used in combination with AlN powder.
• the BET specific surface area of the organic-inorganic composite particle powder was measured by the BET method (nitrogen adsorption 1-point method) using a specific surface area measuring device (manufactured by Shimadzu Corporation: Flowsorb 2-2300 type). For the measurement, 2 g of the organic-inorganic composite particle powder was used, and the one obtained by performing the drying treatment at 100 ° C. for 1 hour in advance in a nitrogen gas flow was used for the measurement.
• the raw material AlN uses water as a solvent at the time of measurement.
• Hydrophobic AlN uses ethanol as the solvent for measurement.
• the particle size distribution of the liquid dispersed by dispersing AlN powder in a solvent at a concentration of 0.2% by mass and irradiating with ultrasonic waves of about 200 W for 2 minutes is measured using a laser diffraction / scattering type particle size distribution meter.
• the volume frequency distribution of the particle size the volume frequency is accumulated from the smaller particle size, and the value of the particle size where the cumulative value is 50% is D 50 , and the value of the particle size where the cumulative value is 90% is D. It was set to 90 . Further, in the present invention, the value of D 50 is taken as the average particle size.
• the carbon content of the hydrophobic AlN powder was measured with a carbon analyzer (for example, EMIA-110 manufactured by HORIBA, Ltd.). The powder was burned in an oxygen stream at 1350 ° C. until carbon dioxide gas was no longer generated, and the carbon content of each powder was quantified from the amount of carbon dioxide generated.
• the carbon content derived from the hydrophobized layer of the hydrophobic AlN powder was calculated using the formula for calculating the carbon content derived from the silane compound shown in the text.
• the hydrophobic group density was calculated from the above carbon content.
• the oxygen concentration of the AlN powder was measured by an oxygen analyzer manufactured by HORIBA, Ltd. It has been confirmed that at least 70% or more of oxygen in the AlN particles is present in the oxide layer on the surface.
• the obtained sample (cured product) and 50 cc of ion-exchanged water were placed in a fluororesin container with a capacity of 50 cc, stored at 120 ° C. for 90 hours, cooled to 10 ° C., and then opened.
• the amount of ammonium ion in the collected water was quantified by ion chromatography, and it was assumed that AlN was hydrolyzed according to the formula (1), and the basic hydrolysis rate in the resin was calculated from the measured value of the ammonium ion.
• a resin composition was prepared by the following method, and the decomposition rate (water resistance) was measured according to the method for measuring the basic hydrolysis rate (water resistance) in the resin.
• ⁇ Epoxy resin composition The following raw materials were weighed and kneaded in a mortar for 15 minutes to obtain a kneaded product. ⁇ Hydrophobic AlN powder 0.47g, -Aluminum oxide powder A20s 1.33g, -Epoxy resin jER828 0.12g, ⁇ Curing agent CureW 0.03g The obtained kneaded product was heat press-molded at 150 ° C. and 20 MPa for 1 hour, and further heated at 180 ° C. for 1 hour to obtain a disc-shaped cured product made of a resin composition having a diameter of 10 mm and a thickness of 1.2 mm.
• ⁇ Acrylic resin composition > The following raw materials were weighed and kneaded in a mortar for 15 minutes to obtain a kneaded product. ⁇ Hydrophobic AlN powder 0.47g -Aluminum oxide powder A20s 1.33g ⁇ Methacrylate Monomer BPE-100 0.105g ⁇ 3G 0.045g ⁇ Perbutyl O 0.001g The obtained kneaded product was heat-press molded at 150 ° C. and 20 MPa for 3 hours to obtain a disc-shaped cured product made of a resin composition having a diameter of 10 mm and a thickness of 1.2 mm.
• Hydrophobic AlN powder was obtained by the method described in the following production example (see Table 1). With respect to the obtained hydrophobic AlN powder, D50 , carbon content, hydrophobic group density, specific surface area, degree of hydrophobicity, powder decomposition rate, and basic hydrolysis rate in resin were measured according to the above-mentioned method. Further, the epoxy resin composition and the acrylic resin composition were produced using the hydrophobic AlN powder, and the water resistance test thereof was performed. The results are summarized in Tables 2 and 3.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Inorganic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=82057789

Family Applications (1)

Country Status (7)

Cited By (4)

Citations (4)

Family Cites Families (9)

• 2021
  • 2021-12-13 DE DE112021006805.9T patent/DE112021006805T5/de active Pending
  • 2021-12-13 CN CN202180075091.3A patent/CN116438237B/zh active Active
  • 2021-12-13 WO PCT/JP2021/045777 patent/WO2022131199A1/ja not_active Ceased
  • 2021-12-13 KR KR1020237015290A patent/KR20230118810A/ko active Pending
  • 2021-12-13 US US18/036,364 patent/US20230416501A1/en not_active Abandoned
  • 2021-12-13 JP JP2022569976A patent/JP7707202B2/ja active Active
  • 2021-12-15 TW TW110146840A patent/TW202231574A/zh unknown

Patent Citations (4)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events