CN114667267A - Boron nitride particles and method for producing same - Google Patents
Boron nitride particles and method for producing same Download PDFInfo
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- CN114667267A CN114667267A CN202080077963.5A CN202080077963A CN114667267A CN 114667267 A CN114667267 A CN 114667267A CN 202080077963 A CN202080077963 A CN 202080077963A CN 114667267 A CN114667267 A CN 114667267A
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- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
- C01B21/064—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with boron
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- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/38—Boron-containing compounds
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L101/00—Compositions of unspecified macromolecular compounds
Abstract
One aspect of the present invention is a method for producing boron nitride particles, including: a reaction step of introducing a 1 st gas containing a boric acid ester and a 2 nd gas containing ammonia into a tubular reactor from one end surface of the reactor, respectively, and reacting the boric acid ester with ammonia at 750 ℃ or higher in the reactor to obtain a precursor of boron nitride particles; and a heating step of heating a precursor of the boron nitride particles at 1000 ℃ or higher to obtain boron nitride particles, wherein in the reaction step, a 1 st gas is introduced into the reactor so that a side surface of the reactor is positioned on an extension of a 1 st direction in which the 1 st gas is introduced into the reactor, and a 2 nd gas is introduced into the reactor so that a side surface of the reactor is positioned on an extension of a 2 nd direction in which the 2 nd gas is introduced into the reactor.
Description
Technical Field
The present invention relates to boron nitride particles and a method for producing the same.
Background
In electronic components such as transistors, thyristors, and CPUs, efficient heat dissipation of heat generated during use is an important issue. Therefore, a heat dissipating member having high thermal conductivity is used together with such electronic components. On the other hand, boron nitride particles have been widely used as a filler in heat dissipation members because of their high thermal conductivity and high insulation properties.
For example, when boron nitride particles are used as a filler in primary sealing of an electronic component, the boron nitride particles preferably have a small particle size so that the boron nitride particles also enter a narrow gap around the electronic component. For example, patent document 1 discloses spherical boron nitride fine particles characterized by an average particle diameter of 0.01 to 1.0 μm, an orientation index of 1 to 15, a boron nitride purity of 98.0 mass% or more, and an average circularity of 0.80 or more, and a method for producing the same.
Documents of the prior art
Patent document
Patent document 1: international publication No. 2015/122379
Disclosure of Invention
Problems to be solved by the invention
According to the studies of the inventors of the present application, when boron nitride particles are used as a filler in primary sealing of electronic components as described above, it is important for the boron nitride particles to have not only a small average particle size but also a small variation in particle size.
Accordingly, an object of one aspect of the present invention is to obtain boron nitride particles with small variations in particle size.
Means for solving the problems
As a result of studies, the inventors of the present application have found that, in a production method for obtaining boron nitride particles from a boric acid ester and ammonia, a method for introducing a boric acid ester-containing gas and an ammonia-containing gas into a reactor is important in order to reduce variations in particle size of the obtained boron nitride particles.
One aspect of the present invention is a method for producing boron nitride particles, including: a reaction step of introducing a 1 st gas containing a boric acid ester and a 2 nd gas containing ammonia into a tubular reactor from one end surface of the reactor, respectively, and reacting the boric acid ester with ammonia at 750 ℃ or higher in the reactor to obtain a precursor of boron nitride particles; and a heating step of heating a precursor of the boron nitride particles at 1000 ℃ or higher to obtain the boron nitride particles, wherein in the reaction step, the 1 st gas is introduced into the reactor such that a side surface of the reactor is positioned on an extension of a 1 st direction in which the 1 st gas is introduced into the reactor, and the 2 nd gas is introduced into the reactor such that a side surface of the reactor is positioned on an extension of a 2 nd direction in which the 2 nd gas is introduced into the reactor.
The angle formed by the 1 st direction and the extension direction of the reactor extending from one end surface to the other end surface may be θ1Tan theta1Is 1.2 or more. The angle formed by the 2 nd direction and the extending direction of the reactor extending from one end face to the other end face may be θ2Tan theta2Is 1.2 or more.
Another aspect of the present invention is boron nitride particles, wherein, in a volume-based particle size distribution, the boron nitride particles have an average particle diameter of 1 μm or less, and a difference between a 10% cumulative particle diameter and a 100% cumulative particle diameter is 5 μm or less.
The average circularity of the boron nitride particles may be 0.8 or more.
Another aspect of the present invention is a resin composition containing a resin, and the above-described boron nitride particles.
ADVANTAGEOUS EFFECTS OF INVENTION
According to one aspect of the present invention, boron nitride particles with small variations in particle size can be obtained.
Drawings
Fig. 1 is a perspective view showing an example of a reactor used in the method for producing boron nitride particles according to the embodiment.
In FIG. 2, (a) is a side view of the reactor as viewed from the 1 st introduction tube side, and (b) is a side view of the reactor as viewed from the 2 nd introduction tube side.
Detailed Description
One embodiment of the present invention is a method for producing boron nitride particles, including: a reaction step in which boric acid ester is reacted with ammonia at 750 ℃ or higher to obtain a precursor of boron nitride particles; and a heating step of heating the precursor of the boron nitride particles at 1000 ℃ or higher to obtain boron nitride particles.
In the reaction step, a 1 st gas containing a borate ester and a 2 nd gas containing ammonia are introduced into the reactor separately from each other.
FIG. 1 is a perspective view showing an example of a reactor. As shown in fig. 1, the reactor 1 is, for example, cylindrical with both ends open (both end surfaces are open surfaces), and has an internal space S between one end surface 1a and the other end surface 1 b. The length of the reactor 1 may be, for example, 1000mm or more and 1600mm or less. The inner diameter of the reactor 1 may be, for example, 30mm or more and 100mm or less.
Both ends of the reactor 1 are held by the holding members 2 so that the outside of the reactor 1 and the internal space S can be isolated (so that the internal space S can be closed as needed). The reactor 1 is provided so that the heating part H is positioned in an electric resistance heating furnace (not shown) in order to heat only a part (hereinafter referred to as "heating part") H between the both end surfaces 1a and 1 b. The length of the heating section H (the length in the longitudinal direction of the reactor 1) may be, for example, 500mm or more and 900mm or less. The boric acid ester is reacted with ammonia in the heating part H by heating the heating part H of the reactor 1. The temperature of the heating section H may be, for example, 750 ℃ or more and 1500 ℃ or less.
On one end surface 1a of the reactor 1, a 1 st introduction pipe 3 and a 2 nd introduction pipe 4 are respectively attached so that gas can be introduced into the internal space S from the outside of the reactor 1. FIG. 2 (a) is a side view of the reactor 1 viewed from the 1 st inlet pipe 3 side. FIG. 2 (b) is a side view of the reactor 1 viewed from the 2 nd inlet pipe 4 side.
As shown in FIG. 1 and FIG. 2 (a)) As shown, the 1 st introduction pipe 3 has a shape in which a cylindrical tip is bent in a predetermined direction, for example. The first introduction pipe 3 is introduced into the internal space S from the outside of the reactor 1 so as to extend substantially parallel to an extending direction D of the reactor 1 extending from the one end surface 1a to the other end surface 1b (extending direction from the one end surface 1a to the other end surface 1 b), and has an angle θ formed toward the extending direction D of the reactor 1 at a position within the internal space S at a distance of, for example, 10 to 40mm from the one end surface 1a1The bending direction d1 extends in a bending manner. The bending direction d1 of the 1 st introduction tube 3 is defined as a direction perpendicular to the distal end surface 3a of the 1 st introduction tube 3.
As shown in fig. 1 and 2 (b), the 2 nd introduction pipe 4 has a shape in which, for example, a cylindrical tip is bent in a predetermined direction. The 2 nd introduction pipe 4 is introduced into the internal space S from the outside of the reactor 1 so as to extend substantially parallel to the extending direction D of the reactor 1, and has an angle θ formed toward the extending direction D of the reactor 1 at a position within the internal space S and at a distance of, for example, 10 to 40mm from the one end surface 1a2The bending direction d2 extends in a bending manner. The bending direction d1 of the 2 nd introduction pipe 4 is defined as a direction perpendicular to the distal end surface 4a of the 2 nd introduction pipe 4.
The angle theta1The side surface 1c of the reactor 1 (side surface along the extending direction D. the same applies hereinafter) is at such an angle that it is located on the extension line of the bending direction D1 of the 1 st introduction tube 3 (the extension line of the bending direction D1 of the 1 st introduction tube 3 intersects with the side surface 1c of the reactor 1). Likewise, the angle θ2The side surface (side surface along the extending direction D) 1c of the reactor 1 is at such an angle as to be located on an extension line of the bending direction D2 of the 2 nd introduction pipe 4 (the extension line of the bending direction D2 of the 2 nd introduction pipe 4 intersects with the side surface 1c of the reactor 1).
In the reaction step, a 1 st gas containing a borate ester is introduced from the outside of the reactor 1 into the internal space S through the 1 st introduction pipe 3, and a 2 nd gas containing ammonia is introduced from the outside of the reactor 1 into the internal space S through the 2 nd introduction pipe 4 separately from the 1 st gas.
The 1 st gas is obtained by, for example, passing an inert gas through a liquid boric acid ester. In this case, the 1 st gas is a gas containing borate and an inert gas. The borate ester may be, for example, an alkyl borate ester, preferably trimethyl borate. Examples of the inert gas include a rare gas such as helium, neon, or argon, and nitrogen. The 2 nd gas is, for example, a gas containing ammonia.
The molar ratio of the amount of ammonia introduced to the amount of borate ester introduced (ammonia/borate ester) may be, for example, 1 or more and 10 or less.
The boric acid ester introduced into the reactor 1 reacts with ammonia in the heated reactor 1 to produce a precursor (white powder) of boron nitride particles. A part of the precursor of the generated boron nitride particles adheres to the inside of the reactor 1, but the precursor of the boron nitride particles is often recovered by feeding the inert gas or unreacted ammonia gas to a recovery vessel (not shown) attached to the other end face 1b side of the reactor 1. The reaction time of reacting the boric acid ester with ammonia is preferably 30 seconds or less from the viewpoint of facilitating reduction in the particle diameter of the obtained boron nitride particles. The reaction time is a time for which the boric acid ester and ammonia stay in the heating section H of the reactor 1, and can be adjusted by the gas flow rate when the 1 st gas and the 2 nd gas are introduced and the length of the heating section H.
In the reaction step described above, the 1 st introduction pipe 3 is arranged at the angle θ as described above1Bent in the bending direction D1, so that the 1 st gas is also bent at an angle θ with respect to the extending direction D of the reactor 11And (3) the 1 st introduction direction (1 st direction) d 1. Also, since the 2 nd introducing pipe 4 is at the angle θ as described above2Bent in the bending direction D2, so that the 2 nd gas also forms an angle theta with the extending direction D of the reactor 12And (2) the 2 nd introduction direction (2 nd direction) d 2. That is, the side surface 1c of the reactor 1 is positioned on an extension line of the introduction direction d1 of the 1 st gas and an extension line of the introduction direction d2 of the 2 nd gas. Similarly to the bending direction d1 of the 1 st introduction tube 3, the 1 st introduction direction d1 is defined as a direction perpendicular to the distal end surface 3a of the 1 st introduction tube 3. The 2 nd introduction direction d2 is defined as a direction perpendicular to the distal end surface 4a of the 2 nd introduction pipe 4, similarly to the bending direction d2 of the 2 nd introduction pipe 4.
In this manner, by introducing the 1 st gas in the 1 st introduction direction d1 and introducing the 2 nd gas in the 2 nd introduction direction d2, variation in particle size of the obtained boron nitride particles can be reduced. The reason for this is not clear, and it is presumed that the 1 st gas and the 2 nd gas are introduced in the 1 st introduction direction D1 and the 2 nd introduction direction D2, respectively, and thereby the 1 st gas and the 2 nd gas each proceed in the reactor 1 at a certain angle with respect to the extending direction D of the reactor 1 while colliding with the side surface 1c of the reactor 1, respectively, and therefore the 1 st gas and the 2 nd gas are easily mixed uniformly with each other, compared to, for example, a case where the 1 st gas and the 2 nd gas are introduced in parallel to the extending direction D of the reactor 1.
The angle θ is from the viewpoint of further reducing the variation in particle size of the obtained boron nitride particles1And theta2Each of the angles is preferably 50 ° or more, more preferably 60 ° or more, further preferably 65 ° or more, and particularly preferably 70 ° or more. Angle theta1And theta2Each below 90 °, for example 80 ° or less. In other words, for the angle θ1And theta2From the viewpoint of further reducing the variation in particle size of the obtained boron nitride particles, tan θ1And tan theta2Each is preferably 1.2 or more, more preferably 1.7 or more, further preferably 2.1 or more, and particularly preferably 2.7 or more. tan theta1And tan theta2Each may be, for example, 11.4 or less.
In the heating step, the boron nitride particle precursor obtained in the reaction step is heated at 1000 ℃ or higher to obtain boron nitride particles. The heating process may include, for example: a 1 st heating step of heating a boron nitride particle precursor at 1000 to 1600 ℃ to obtain a 1 st precursor; a 2 nd heating step of heating the 1 st precursor at 1000 to 1600 ℃ to obtain a 2 nd precursor; and a 3 rd heating step of heating the 2 nd precursor at 1800 to 2200 ℃ to obtain boron nitride particles. At this time, after the 1 st heating step is completed and before the 2 nd heating step is started, the ambient temperature in which the 1 st precursor is left is temporarily lowered to normal temperature (10 to 30 ℃). In another embodiment, the heating step may be performed by omitting the 1 st heating step and performing the 2 nd and 3 rd heating steps.
In the 1 st heating step, the boron nitride particle precursor obtained in the reaction step is placed in another reaction tube (for example, an alumina tube) provided in the resistance heating furnace, and nitrogen gas and ammonia gas are introduced into the reaction tube, respectively. In this case, the introduced gas may be only ammonia gas. The flow rates of nitrogen and ammonia gas may be adjusted appropriately so that the reaction time is a desired value. For example, the more the flow rates of nitrogen and ammonia, the shorter the reaction time.
Then, the reaction tube is heated to 1000-1600 ℃. The heating time may be, for example, 1 hour or more, or 10 hours or less. Thus, the 1 st precursor was obtained.
After the 1 st heating step, the power supply of the resistance heating furnace was cut off, the introduction of nitrogen gas and ammonia gas was stopped, and the 1 st precursor was allowed to stand in a state where the temperature in the reaction tube was lowered to normal temperature (10 to 30 ℃). The time for standing may be, for example, 0.5 hour or more and 96 hours or less.
In the heating step 2, nitrogen gas and ammonia gas are reintroduced into the reaction tube, and the reaction tube is reheated to 1000 to 1600 ℃. The flow rates of nitrogen gas and ammonia gas and the heating time may be the same as those in the example described in the 1 st heating step. The conditions in the 1 st heating step and the conditions in the 2 nd heating step may be the same as or different from each other. Thus, the 2 nd precursor was obtained.
In the 3 rd heating step, the 2 nd precursor obtained in the 2 nd heating step is put into a boron nitride crucible, and heated to 1800 to 2200 ℃ in a nitrogen atmosphere in an induction heating furnace. The heating time may be, for example, 0.5 hour or more and 10 hours or less. Thereby, boron nitride particles can be obtained.
By the above-described production method, for example, the following boron nitride particles can be obtained: in the volume-based particle size distribution, the average particle diameter is 1 μm or less, and the difference between the 10% cumulative particle diameter and the 100% cumulative particle diameter is 10 μm or less. That is, another embodiment of the present invention is the following boron nitride particles: in the volume-based particle size distribution, the average particle diameter is 1 μm or less, and the difference (D100-D10) between the 10% cumulative particle diameter (D10) and the 100% cumulative particle diameter (D100) is 10 μm or less.
From the viewpoint of reducing the dielectric constant of a heat dissipating member containing boron nitride particles (hereinafter also simply referred to as "heat dissipating member"), the average particle diameter of the boron nitride particles may preferably be 0.9 μm or less, 0.8 μm or less, or 0.7 μm or less. The average particle diameter of the boron nitride particles may preferably be 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, 0.3 μm or more, or 0.4 μm or more, from the viewpoint of suppressing an increase in viscosity when the boron nitride particles are mixed with a resin.
From the viewpoint of reducing the dielectric constant of the heat dissipating member and suppressing variation in particle size, and being more suitable for primary sealing of electronic components, the D100-D10 of the boron nitride particles may preferably be 5 μm or less, 4 μm or less, or 3 μm or less. The boron nitride particles may have a D100-D10 value of, for example, 0.5 μm or more, 0.8 μm or more, or 1 μm or more.
The average particle diameter of the boron nitride particles and D100 to D10 were measured by the following procedure.
A 0.125 mass% aqueous solution of sodium hexametaphosphate was prepared using distilled water as a dispersion medium for dispersing boron nitride particles and sodium hexametaphosphate as a dispersant. To this aqueous solution, boron nitride particles were added at a ratio of 0.1g/80mL, and the resulting mixture was ultrasonically dispersed by an ultrasonic homogenizer (for example, manufactured by Nippon Seiko Seisakusho K.K., trade name: US-300E) at an AMPLITUDE of 80% 1 minute by 30 seconds to prepare a boron nitride particle dispersion. The dispersion was collected while stirring at 60rpm, and the volume-based particle size distribution was measured by a laser diffraction scattering particle size distribution measuring apparatus (for example, product name: LS-13320 manufactured by Beckman Coulter). At this time, 1.33 was used as the refractive index of water, and 1.7 was used as the refractive index of boron nitride particles. From the measurement results, an average particle diameter was calculated as a particle diameter (median particle diameter, D50) of a cumulative value of 50% of the cumulative particle size distribution, and D100 to D10 were calculated as a value obtained by subtracting a particle diameter D10 of a cumulative value of 10% from a particle diameter D100 of a cumulative value of 100% of the cumulative particle size distribution.
The boron nitride particles preferably have a spherical shape or a shape close to a spherical shape from the viewpoints of improving the filling property in the production of the heat dissipating member and making the characteristics (thermal conductivity, dielectric constant, and the like) of the heat dissipating member isotropic. From the same viewpoint, the average circularity of the boron nitride particles is preferably 0.8 or more, 0.82 or more, 0.84 or more, 0.86 or more, or may be 0.88 or more.
The average circularity of boron nitride particles was measured by the following procedure.
The projected area (S) and the perimeter (L) of the boron nitride particles were calculated from an image of the boron nitride particles (magnification: 10,000 times, image resolution: 1280X 1024 pixels) captured by a Scanning Electron Microscope (SEM) by image analysis software (for example, MacView, product name, manufactured by Mountech). Using the projected area (S) and the perimeter (L), the circularity is determined according to the following equation:
circularity 4 pi S/L2。
The average value of circularities obtained for arbitrarily selected 100 boron nitride particles was defined as an average circularity.
The boron nitride particles described above are suitable for use in, for example, heat dissipation members. By using the boron nitride particles, a heat dissipating member having a low dielectric constant can be obtained. When the boron nitride particles are used for a heat dissipating member, they are used, for example, as a resin composition mixed with a resin. That is, another embodiment of the present invention is a resin composition containing a resin and the boron nitride particles.
The content of the boron nitride particles is preferably 30 vol% or more, more preferably 40 vol% or more, and further preferably 50 vol% or more based on the total volume of the resin composition, from the viewpoint of improving the thermal conductivity of the resin composition and easily obtaining excellent heat dissipation performance, and is preferably 85 vol% or less, more preferably 80 vol% or less, and further preferably 70 vol% or less from the viewpoint of suppressing generation of voids during molding and lowering of insulation and mechanical strength.
Examples of the resin include an epoxy resin, a silicone rubber, an acrylic resin, a phenol resin, a melamine resin, a urea resin, an unsaturated polyester, a fluororesin, a polyolefin (such as polyethylene), polyimide, polyamideimide, polyetherimide, polybutylene terephthalate, polyethylene terephthalate, polyphenylene ether, polyphenylene sulfide, a wholly aromatic polyester, polysulfone, a liquid crystal polymer, polyether sulfone, polycarbonate, a maleimide-modified resin, an ABS (acrylonitrile-butadiene-styrene) resin, an AAS (acrylonitrile-acrylic rubber-styrene) resin, and an AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin.
The content of the resin may be 15 vol% or more, 20 vol% or more, or 30 vol% or more, and may be 70 vol% or less, 60 vol% or less, or 50 vol% or less, based on the total volume of the resin composition.
The resin composition may further contain a curing agent for curing the resin. The curing agent may be appropriately selected according to the kind of the resin. For example, when the resin is an epoxy resin, examples of the curing agent include a phenolic Novolac compound, an acid anhydride, an amino compound, and an imidazole compound. The content of the curing agent may be, for example, 0.5 parts by mass or more or 1.0 parts by mass or more, or 15 parts by mass or less or 10 parts by mass or less, with respect to 100 parts by mass of the resin.
The resin composition may further contain boron nitride particles other than the above-described boron nitride particles (for example, known boron nitride particles such as bulk boron nitride particles in which scaly primary particles are aggregated).
Examples
The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
Production example 1
Boron nitride particles were produced by the following procedure.
First, in the reaction step, a cylindrical reactor (quartz tube, length of reactor: 1300mm, inner diameter of reactor: 75mm, positioned at the resistor) as shown in FIG. 1 was placed in a resistance heating furnaceLength of portion inside the heating furnace: 800mm) and heated to 1150 ℃. On the other hand, the 1 st gas obtained by passing nitrogen through trimethyl borate was introduced into the reactor from the 1 st inlet pipe. On the other hand, ammonia gas was introduced directly into the reactor. As the 1 st and 2 nd introduction pipes, in the internal space of the reactor, at a position spaced 25mm from one end surface of the reactor, angles θ formed with respect to the extending direction of the reactor were set1And theta2The bending direction of the guide tube. In other words, the angles formed by the 1 st and 2 nd introduction directions of the introduced gas and the extending direction of the reactor are each θ1And theta2In the method (1), the 1 st gas and the 2 nd gas are introduced. In addition, θ1And theta2Each is such that tan θ1And tan theta2The angles are the values shown in table 1.
The molar ratio of the introduced amount of ammonia to the introduced amount of trimethyl borate (ammonia/trimethyl borate) was 4.5. Thus, trimethyl borate was reacted with ammonia to obtain a precursor (white powder) of boron nitride particles. The reaction time was set to 10 seconds.
Next, in the heating step, the precursor of the boron nitride particles obtained in the reaction step was charged into another reaction tube (alumina tube) provided in the resistance heating furnace, and nitrogen gas and ammonia gas were introduced into the reaction tube at flow rates of 10L/min and 15L/min, respectively. Further, the reaction tube was heated at 1500 ℃ for 2.5 hours. Thereby, the 1 st precursor was obtained (1 st heating step).
Next, the power supply to the resistance heating furnace was cut off, the introduction of nitrogen gas and ammonia gas was stopped, the temperature in the reaction tube was lowered to 25 ℃, and the 1 st precursor was allowed to stand for 2 hours in this state.
Next, introduction of nitrogen gas and ammonia gas and heating in the reaction tube were performed under the same conditions as in the first heating step 1. Thereby, the 2 nd precursor was obtained (2 nd heating step).
Next, the 2 nd precursor obtained in the 2 nd heating step was charged into a crucible made of boron nitride, and heated at 2000 ℃ for 5 hours in a nitrogen atmosphere in an induction heating furnace. Thereby, boron nitride particles were obtained.
Production examples 2 and 3
The introduction direction of the 1 st gas and the introduction direction of the 2 nd gas were changed so that tan θ1And tan theta2Angle θ having the value shown in Table 11And theta2Except for this, boron nitride particles were produced in the same manner as in production example 1.
The average particle diameter, the difference between the 10% cumulative particle diameter and the 100% cumulative particle diameter (D100 to D10), and the average circularity were measured for each of the obtained boron nitride particles by the following methods. The results are shown in Table 1.
(average particle diameter and D100-D10)
A 0.125 mass% aqueous solution of sodium hexametaphosphate was prepared using distilled water as a dispersion medium for dispersing boron nitride particles and sodium hexametaphosphate as a dispersant. Boron nitride particles were added to the aqueous solution at a ratio of 0.1g/80mL, and the resulting mixture was ultrasonically dispersed by an ultrasonic homogenizer (manufactured by Nippon Seiko Seisakusho K.K., trade name: US-300E) under the condition of AMPLITUDE (AMPLITUDE) of 80% for 1 minute and 30 seconds to prepare a boron nitride particle dispersion. The dispersion was collected while stirring at 60rpm, and the volume-based particle size distribution was measured by a laser diffraction scattering particle size distribution measuring apparatus (product name: LS-13320, manufactured by Beckman Coulter). At this time, 1.33 was used as the refractive index of water, and 1.7 was used as the refractive index of boron nitride particles. From the measurement results, an average particle diameter was calculated as a particle diameter (median particle diameter, D50) of 50% of the cumulative value of the cumulative particle size distribution, and D100 to D10 were calculated as a value obtained by subtracting a particle diameter D10 of 10% of the cumulative value from a particle diameter D100 of 100% of the cumulative particle size distribution.
(average circularity degree)
First, the projection area (S) and the perimeter (L) of the boron nitride particles are calculated by image analysis using image analysis software (for example, MacView, product name, manufactured by Mountech) on an image of the boron nitride particles (magnification: 10,000 times, image resolution: 1280X 1024 pixels) captured by a Scanning Electron Microscope (SEM). Then, using the projected area (S) and the perimeter (L), the circularity is obtained according to the following equation:
circularity 4 pi S/L2。
The average value of circularities obtained for arbitrarily selected 100 boron nitride particles was calculated as an average circularity.
The dielectric constant of each of the obtained boron nitride particles was measured by the following method. The results are shown in Table 1.
The boron nitride particles were kneaded with polyethylene (trade name "Novatech HY 540", manufactured by japan polyethylene corporation) in an amount of 20 vol% of the boron nitride particles, and sheet-formed to obtain a sheet having a thickness of 0.2 mm. A twin-screw extruder was used to perform kneading and sheet molding at a temperature of 180 ℃. The obtained sheet was measured at a frequency of 36GHz and a temperature of 25 ℃ by using a measuring apparatus of the cavity resonator method, and the dielectric constant of the sheet was determined.
[ Table 1]
Description of the reference numerals
The reactor system comprises a 1 … reactor, one end face of a 1a … reactor, the other end face of a 1b … reactor, the side face of a 1c … reactor, 2 … holding members, a 3 … st introduction pipe 1, the front end face of a 3a … st introduction pipe 1, a 4 … nd introduction pipe 2, the front end face of a 4a … nd introduction pipe 2, the extending direction of a D … reactor, the internal space of an S … reactor, the introduction direction of a D1 … th gas 1, and the introduction direction of a D2 … nd gas 2.
Claims (6)
1. A method for producing boron nitride particles, comprising:
a reaction step of introducing a 1 st gas containing a boric acid ester and a 2 nd gas containing ammonia into a tubular reactor from one end surface of the reactor, respectively, and reacting the boric acid ester and the ammonia in the reactor at 750 ℃ or higher to obtain a precursor of boron nitride particles; and
a heating step of heating the boron nitride particle precursor at 1000 ℃ or higher to obtain boron nitride particles,
in the reaction step, the 1 st gas is introduced into the reactor such that a side surface of the reactor is positioned on an extension of a 1 st direction in which the 1 st gas is introduced into the reactor, and the 2 nd gas is introduced into the reactor such that a side surface of the reactor is positioned on an extension of a 2 nd direction in which the 2 nd gas is introduced into the reactor.
2. The production method according to claim 1, wherein θ is an angle formed between the 1 st direction and an extending direction of the reactor extending from the one end surface to the other end surface1Tan theta1Is 1.2 or more.
3. The production method according to claim 1 or 2, wherein an angle formed by the 2 nd direction and an extending direction extending from the one end surface to the other end surface of the reactor is represented by θ2Tan θ2Is 1.2 or more.
4. Boron nitride particles, wherein the boron nitride particles have an average particle diameter of 1 μm or less and a difference between a 10% cumulative particle diameter and a 100% cumulative particle diameter of 5 μm or less in a volume-based particle size distribution.
5. The boron nitride particles according to claim 4, wherein the average circularity is 0.8 or more.
6. A resin composition comprising a resin and the boron nitride particles according to claim 4 or 5.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019221272 | 2019-12-06 | ||
| JP2019-221272 | 2019-12-06 | ||
| PCT/JP2020/043466 WO2021111909A1 (en) | 2019-12-06 | 2020-11-20 | Boron nitride particles and method for manufacturing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114667267A true CN114667267A (en) | 2022-06-24 |
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| CN (1) | CN114667267A (en) |
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| WO (1) | WO2021111909A1 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1364728A (en) * | 2002-02-07 | 2002-08-21 | 山东大学 | Process for preparing nitride ultromicro powder and nitride crystal wunder hydrothermal condition |
| JP2008038163A (en) * | 2006-08-01 | 2008-02-21 | Napura:Kk | Nano spherical particle having composite structure, powder and method for producing the same |
| US20110033707A1 (en) * | 2009-02-03 | 2011-02-10 | National Institute For Materials Science | Spherical boron nitride nanoparticles and synthetic method thereof |
| CN105980298A (en) * | 2014-02-12 | 2016-09-28 | 电化株式会社 | Spherical boron nitride particles and production method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3469941A (en) * | 1967-09-05 | 1969-09-30 | Green Refractories | Ultrafine boron nitride and process of making same |
| FR3008223B1 (en) * | 2013-07-08 | 2017-01-27 | Univ Paul Sabatier - Toulouse Iii | ELECTRICALLY INSULATING COMPOSITE MATERIAL, METHOD OF MANUFACTURING SUCH MATERIAL, AND ITS USE AS ELECTRIC INSULATION |
| CN107161960B (en) * | 2017-06-06 | 2019-05-31 | 哈尔滨工业大学深圳研究生院 | A kind of high pressure vapor prepares the method and apparatus of boron nitride spherical powder |
| JP6692050B2 (en) * | 2017-11-01 | 2020-05-13 | デンカ株式会社 | Boron nitride-containing resin composition |
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- 2020-11-20 WO PCT/JP2020/043466 patent/WO2021111909A1/en active Application Filing
- 2020-11-20 JP JP2021562573A patent/JPWO2021111909A1/ja active Pending
- 2020-11-20 CN CN202080077963.5A patent/CN114667267A/en active Pending
- 2020-12-01 TW TW109142138A patent/TW202128552A/en unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1364728A (en) * | 2002-02-07 | 2002-08-21 | 山东大学 | Process for preparing nitride ultromicro powder and nitride crystal wunder hydrothermal condition |
| JP2008038163A (en) * | 2006-08-01 | 2008-02-21 | Napura:Kk | Nano spherical particle having composite structure, powder and method for producing the same |
| US20110033707A1 (en) * | 2009-02-03 | 2011-02-10 | National Institute For Materials Science | Spherical boron nitride nanoparticles and synthetic method thereof |
| CN105980298A (en) * | 2014-02-12 | 2016-09-28 | 电化株式会社 | Spherical boron nitride particles and production method thereof |
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| WO2021111909A1 (en) | 2021-06-10 |
| JPWO2021111909A1 (en) | 2021-06-10 |
| TW202128552A (en) | 2021-08-01 |
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