magnesium oxide

Abstract

The purpose of this disclosure is to provide a magnesium oxide with good moisture resistance. The magnesium oxide of this disclosure has a dyne value of less than 50 mN / m and a specific surface area of ​​0.01 m². 2 / g or more and less than 1.3m 2 / g.

Description

Technical Field

[0001] This disclosure relates to a magnesium oxide. Background Technology

[0002] Magnesium oxide can be used in thermally conductive materials, heat-resistant materials, electrical insulating materials, fillers, optical materials, polishing agents, etc. Patent document 1 describes a method for manufacturing magnesium oxide, in which magnesium hydroxide having a specified particle size and BET specific surface area is calcined at 1100-1600°C, and then pulverized and classified to a secondary particle size of less than 20 μm.

[0003] Patent document 2 describes a thermally conductive filler, which is magnesium oxide, and uses (C) k H (2k+1) ) n -S(OC m H (2m+1) ) (4-n) The coating agent, represented by [k: 6 or more, m: 2 or less, n: 1 to 3], is used to coat magnesium oxide with 1 to 10% by mass, and has a specified BET specific surface area and average secondary particle size.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 6-171928

[0007] Patent Document 2: Japanese Patent Application Publication No. 2011-68757 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The purpose of this disclosure is to provide magnesium oxide with good moisture resistance. Preferably, the purpose of this disclosure is to provide magnesium oxide that, when mixed with resin, can suppress the increase in viscosity of the mixture. Furthermore, preferably, the purpose of this disclosure is to provide magnesium oxide that, when mixed with resin, can suppress the increase in torque during stirring of the mixture.

[0010] Methods for solving problems

[0011] The first embodiment of this disclosure provides a magnesium oxide having a dyne value of 50 mN / m or less.

[0012] The specific surface area of ​​the aforementioned magnesium oxide can be 0.01 m². 2 / g or more and less than 1.3m 2 / g.

[0013] The first-2 embodiment of this disclosure is the first-1 embodiment, wherein the average particle size of the magnesium oxide can be 0.5 μm or more and 50 μm or less.

[0014] The first-third embodiment of this disclosure is in any one of the first-first and second embodiments, wherein the magnesium oxide described above may have a surface treatment layer.

[0015] The I-3 embodiment of this disclosure is in any one of the I-1 and I-2 embodiments, wherein the surface treatment layer is formed using a surface treatment agent containing a silane coupling agent.

[0016] The first-fourth embodiment of this disclosure is in any of the first-third embodiments, wherein the silane coupling agent described above may comprise a compound represented by the following formula (1):

[0017] R 1 n -S(OR 2 ) m ···(1)

[0018] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0019] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0020] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups.

[0021] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0022] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0023] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0024] In the above formula (1), m can represent an integer from 1 to 3.

[0025] The I-5 embodiments of this disclosure are any one of the I-3 and I-4 embodiments.

[0026] The value r is represented by the following equation (2). s It can be above 100% and below 4,000%.

[0027] [Number 1]

[0028]

[0029] In formula (2),

[0030] n s Indicates the amount of substance (mol) of the silane coupling agent.

[0031] N A Avogadro's constant (mol) -1 ),

[0032] S s This represents the area occupied by one molecule of silane coupling agent (m²). 2 ),

[0033] m m This indicates the amount of magnesium oxide added (g).

[0034] s m The specific surface area of ​​magnesium oxide (m²) 2 ·g -1 ).

[0035] Embodiments I-6 of this disclosure provide a magnesium oxide having a torque of 50 N·m or less, as measured by the following method.

[0036] Furthermore, in any one of the embodiments I-1 to I-5 of this disclosure, the torque measured by the following method can be 50 N·m or less.

[0037] [Methods for measuring torque]

[0038] The ethylene-octene polyolefin resin was heated to 120°C and mixed for 10 minutes. Then, magnesium oxide was added to the ethylene-octene polyolefin resin at a volume ratio of 51:49. The mixture was further mixed at 120°C for 15 minutes, and the torque (N·m) was measured at 30 rpm.

[0039] The first-seventh embodiment of this disclosure is any one of the first-1 to first-6 embodiments, wherein the magnesium oxide described herein may have a surface treatment layer.

[0040] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0041] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0042] R 1 n -S(OR 2 ) m ···(1)

[0043] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0044] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0045] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, preferably, can be independently represented by a group selected from C. 1-30 Alkyl and C 2-30 One of the alkenyl groups.

[0046] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0047] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0048] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0049] In the above formula (1), m can represent an integer from 1 to 3.

[0050] Embodiments I-8 of this disclosure provide a magnesium oxide having a viscosity of 70 Pa·s or less, as determined by the following method.

[0051] Furthermore, in any one of the embodiments I-1 to I-7 of this disclosure, the viscosity measured by the following method can be 70 Pa·s or less.

[0052] Methods for measuring viscosity

[0053] Bisphenol-type epoxy resin and magnesium oxide were mixed at a volume ratio of 70:30. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 25°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0054] The first-9 embodiments of this disclosure are any of the first-1 to first-8 embodiments, wherein the magnesium oxide may have a surface treatment layer.

[0055] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0056] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0057] R 1 n -S(OR 2 ) m ···(1)

[0058] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0059] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0060] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, preferably, can be independently represented by a group selected from C. 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0061] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0062] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0063] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0064] In the above formula (1), m can represent an integer from 1 to 3.

[0065] Embodiments I-10 of this disclosure provide a magnesium oxide having a viscosity of 19 Pa·s or less, as determined by the following method.

[0066] Furthermore, in any one of the embodiments I-1 to I-9 of this disclosure, the viscosity measured by the following method can be 70 Pa·s or less.

[0067] Methods for measuring viscosity

[0068] A multifunctional acrylic monomer was mixed with magnesium oxide at a volume ratio of 60:40. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 23°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0069] The first-11th embodiment of this disclosure is any one of the first-1 to first-10 embodiments, wherein the magnesium oxide may have a surface treatment layer.

[0070] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0071] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0072] R 1 n -S(OR 2 ) m ···(1)

[0073] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0074] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0075] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4One of the three groups, preferably, can be independently represented by a group selected from C. 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0076] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0077] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0078] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0079] In the above formula (1), m can represent an integer from 1 to 3.

[0080] Embodiments I-12 of this disclosure provide a method for manufacturing magnesium oxide, comprising surface treating a first magnesium oxide with a surface treatment agent containing a silane coupling agent to obtain a second magnesium oxide having a surface treatment layer.

[0081] The surface treatment described above is carried out using a wet process.

[0082] The I-13th embodiment of this disclosure is the same as the I-12 embodiment, in which the above-mentioned surface treatment can be implemented by a processing method including the following steps: mixing an organic solvent with a first magnesium oxide to obtain a first mixture.

[0083] The above processing method may include the following steps: mixing the above surface treatment agent with the above first mixture to obtain the second mixture.

[0084] The above processing method may include the following steps: removing the organic solvent from the above second mixture to obtain the second magnesium oxide precursor.

[0085] The above processing method may include the following steps: heating and / or drying the above-mentioned second magnesium oxide precursor to obtain a second magnesium oxide with a surface treatment layer.

[0086] Embodiment I-14 of this disclosure provides a heat dissipation component comprising magnesium oxide as described in any one of embodiments I-1 to I-11.

[0087] Embodiments I-15 of this disclosure provide a heat dissipation filler comprising magnesium oxide as described in any one of embodiments I-1 to I-11.

[0088] The first-16th embodiment of this disclosure provides an apparatus comprising a heat dissipation component as described in any one of the first-14 embodiments.

[0089] The II-1 embodiment of this disclosure provides a magnesium oxide having a dyne value of 45 mN / m or less.

[0090] The second embodiment of this disclosure is the same as the first embodiment, wherein the specific surface area of ​​the magnesium oxide described above can be 1.3 m². 2 / g or more and 10m 2 / g or less.

[0091] The II-3 embodiment of this disclosure is in any one of the II-1 and II-2 embodiments, wherein the average particle size of the magnesium oxide can be 0.5 μm or more and 50 μm or less.

[0092] The II-4 embodiment of this disclosure is in any one of the II-1 and II-2 embodiments, wherein the magnesium oxide described above may have a surface treatment layer.

[0093] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0094] The II-5 embodiment of this disclosure is any one of the II-4 embodiments, wherein the silane coupling agent described above may comprise a compound represented by the following formula (1):

[0095] R 1 n -Si-(OR 2 ) m ···(1)

[0096] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0097] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0098] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups.

[0099] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0100] R in the above formula (1) 2 Each can be represented independently of the other. 1-4Alkyl or hydrogen atom.

[0101] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0102] In the above formula (1), m can represent an integer from 1 to 3.

[0103] The II-6 embodiment of this disclosure is any one of the II-4 and II-5 embodiments.

[0104] The value r is represented by the following equation (2). s It can be between 40% and 500%.

[0105] [Number 2]

[0106]

[0107] In formula (2),

[0108] n s Indicates the amount of substance (mol) of the silane coupling agent.

[0109] N A Avogadro's constant (mol) -1 ),

[0110] S s This represents the area occupied by one molecule of silane coupling agent (m²). 2 ),

[0111] m m This indicates the amount of magnesium oxide added (g).

[0112] s m The specific surface area of ​​magnesium oxide (m²) 2 ·g -1 ).

[0113] Embodiments II-7 of this disclosure provide a magnesium oxide having a torque of 53 N·m or less as measured by the following method.

[0114] Furthermore, in any one of the embodiments II-1 to II-6 of this disclosure, the torque measured by the following method can be 53 N·m or less.

[0115] [Methods for measuring torque]

[0116] The ethylene-octene polyolefin resin was heated to 120°C and mixed for 10 minutes. Then, magnesium oxide was added to the ethylene-octene polyolefin resin at a volume ratio of 51:49. The mixture was further mixed at 120°C for 15 minutes, and the torque (N·m) was measured at 30 rpm.

[0117] The II-8 embodiment of this disclosure is any one of the II-1 to II-7 embodiments, wherein the magnesium oxide described herein may have a surface treatment layer.

[0118] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0119] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0120] R 1 n -Si-(OR 2 ) m ···(1)

[0121] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0122] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0123] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, preferably, can be independently represented by a group selected from C. 1-30 Alkyl and -SiR 4 One of the three groups.

[0124] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0125] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0126] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0127] In the above formula (1), m can represent an integer from 1 to 3.

[0128] Embodiments II-9 of this disclosure provide a magnesium oxide having a viscosity of 130 Pa·s or less, as determined by the following method.

[0129] Furthermore, in any one of the embodiments II-1 to II-8 of this disclosure, the viscosity measured by the following method can be 130 Pa·s or less.

[0130] Methods for measuring viscosity

[0131] Bisphenol-type epoxy resin and magnesium oxide were mixed at a volume ratio of 70:30. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 25°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0132] The II-10 embodiment of this disclosure is any one of the II-1 to II-9 embodiments, wherein the magnesium oxide described herein may have a surface treatment layer.

[0133] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0134] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0135] R 1 n -Si-(OR 2 ) m ···(1)

[0136] R in the above formula (1) 1 Each can be represented independently -L 1 -R 3 .

[0137] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0138] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, preferably selected from C 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0139] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0140] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0141] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0142] In the above formula (1), m can represent an integer from 1 to 3.

[0143] Embodiment II-11 of this disclosure provides a magnesium oxide having a viscosity of 27 Pa·s or less, as determined by the following method.

[0144] Furthermore, in any one of the embodiments II-1 to II-10 of this disclosure, the viscosity measured by the following method can be 27 Pa·s or less.

[0145] Methods for measuring viscosity

[0146] A multifunctional acrylic monomer was mixed with magnesium oxide at a volume ratio of 60:40. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 23°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0147] The II-12 embodiment of this disclosure is any one of the II-1 to II-11 embodiments, wherein the magnesium oxide described herein may have a surface treatment layer.

[0148] The aforementioned surface treatment layer can be formed using a surface treatment agent containing a silane coupling agent.

[0149] The above-mentioned silane coupling agent may comprise a compound represented by the following formula (1):

[0150] R 1 n -Si-(OR 2 ) m ···(1)

[0151] R in the above formula (1) 1 Each can be represented independently -L 1 -R3 .

[0152] L in the above formula (1) 1 Each can independently represent a single bond or a divalent organic group.

[0153] R in the above formula (1) 3 Each can be independently represented from C. 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, preferably, can be independently represented by a group selected from C. 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0154] R in the above formula (1) 4 Each can be represented independently of the other. 1-6 Hydrocarbon group.

[0155] R in the above formula (1) 2 Each can be represented independently of the other. 1-4 Alkyl or hydrogen atom.

[0156] In the above formula (1), n ​​can represent an integer from 1 to 3.

[0157] In the above formula (1), m can represent an integer from 1 to 3.

[0158] Embodiments II-13 of this disclosure provide a method for manufacturing magnesium oxide, comprising surface treating a first magnesium oxide with a surface treatment agent containing a silane coupling agent to obtain a second magnesium oxide having a surface-treated layer.

[0159] The surface treatment described above is carried out using a wet process.

[0160] The II-14 embodiment of this disclosure is the same as the II-13 embodiment, wherein the above-mentioned surface treatment can be carried out by a processing method including the following steps: mixing an organic solvent with a first magnesium oxide to obtain a first mixture.

[0161] The above processing method may include: mixing the above surface treatment agent with the above first mixture to obtain a second mixture.

[0162] The above processing method may include: removing the organic solvent from the above second mixture to obtain the second magnesium oxide precursor.

[0163] The above processing method may include: heating and / or drying the above-mentioned second magnesium oxide precursor to obtain a second magnesium oxide with a surface treatment layer.

[0164] Embodiment II-15 of this disclosure provides a heat dissipation component comprising magnesium oxide as described in any one of embodiments II-1 to II-12.

[0165] Embodiment II-16 of this disclosure provides a heat dissipation filler comprising magnesium oxide as described in any one of embodiments II-1 to II-12.

[0166] Embodiment II-17 of this disclosure provides an apparatus comprising a heat dissipation component as described in any one of embodiments II-15.

[0167] Invention Effects

[0168] According to this disclosure, a magnesium oxide with good moisture resistance can be provided. Preferably, this disclosure provides a magnesium oxide that, when mixed with a resin, can suppress the increase in viscosity of the mixture. Furthermore, preferably, this disclosure provides a magnesium oxide that, when mixed with a resin, can suppress the increase in torque during stirring of the mixture. Detailed Implementation

[0169] In Scheme I, the dyne value of magnesium oxide disclosed herein is less than 50 mN / m.

[0170] In Scheme II, the dyne value of magnesium oxide disclosed herein is less than 45 mN / m.

[0171] It should be noted that, unless otherwise stated, the following text implies that either Option I or Option II is applicable.

[0172] The magnesium oxide disclosed herein exhibits excellent moisture resistance. In a preferred embodiment, the magnesium oxide of this disclosure maintains excellent moisture resistance even with prolonged use. Therefore, the formation of Mg(OH)₂ from the reaction of MgO with water can be suppressed, and acid resistance can also be improved. Furthermore, the magnesium oxide of this disclosure exhibits good affinity with resins and good dispersibility in resins. As a result, the thermal conductivity of resin materials containing the magnesium oxide of this disclosure can be improved. This disclosure should not be construed as limiting to a particular theory; the reasons for the improved moisture resistance of the magnesium oxide of this disclosure are considered to be as follows.

[0173] That is, the dyne value is a numerical value that can be used as an indicator of surface free energy. The larger the dyne value, the higher the surface free energy, and the smaller the dyne value, the lower the surface free energy. In the magnesium oxide disclosed in this invention, it is believed that by reducing its surface free energy, the interaction with water can be suppressed, thereby improving its moisture resistance.

[0174] In this disclosure, "magnesium oxide" is not limited to magnesium oxide in compound form, but may also include materials with magnesium oxide as the main component that have undergone surface treatment or other treatments. In this specification, magnesium oxide as a compound is sometimes referred to as "MgO". It should be noted that magnesium oxide (MgO) as the above-mentioned compound may contain elements such as Ca, Si, Cl, S, Al, and Fe as impurities.

[0175] In Scheme I, the dyne value of magnesium oxide is less than 50 mN / m, preferably 15 mN / m or more and 50 mN / m or less, more preferably 20 mN / m or more and 45 mN / m or less. The dyne value of magnesium oxide is preferably 50 mN / m or less, more preferably 45 mN / m or less, further preferably 40 mN / m or less, and preferably 15 mN / m or more, more preferably 20 mN / m or more.

[0176] In Scheme II, the dyne value of magnesium oxide is less than 45 mN / m, preferably 15 mN / m or more and 40 mN / m or less, more preferably 20 mN / m or more and 35 mN / m or less. The dyne value of magnesium oxide is preferably 45 mN / m or less, more preferably 40 mN / m or less, further preferably 35 mN / m or less, and preferably 15 mN / m or more, more preferably 20 mN / m or more.

[0177] The dyne value of magnesium oxide can be determined by the following methods.

[0178] [Methods for determining dyne value]

[0179] Prepare solutions with dyne values ​​of 25.4 mN / m, 30.0 mN / m, 35.0 mN / m, 40.0 mN / m, 45.0 mN / m, and 50.0 mN / m, as well as water. Measure 2 mL of each liquid into a clean glass container and adjust the liquid temperature to 25°C. Use a glass container where the liquid level is at least 5 mm above the bottom. Next, dry the sample at 60°C for 1 hour, then adjust the sample temperature to 25°C. Then, sprinkle 0.01 g of the sample onto the surface of each liquid. After 10 seconds, the lowest dyne value among the liquids that completely float on the surface is taken as the sample's dyne value.

[0180] In this disclosure, magnesium oxide is preferably magnesium oxide particles. In this disclosure, "particle" refers to an aggregate of independent particulate materials. The shape of each particle can be spherical, irregular, etc. When the shape of each particle is spherical, "spherical" is not limited to "true spherical".

[0181] In Scheme I, the specific surface area of ​​magnesium oxide is 0.01 m². 2 / g or more and less than 1.3m 2 / g, preferably 0.05m 2 / g or more and 1m 2 / g or less, more preferably 0.1m 2 / g or more and 1.0m 2 The specific surface area of ​​magnesium oxide is less than 0.01 m² / g. 2 / g or more, preferably 0.05m 2 / g or more, more preferably 0.1m 2 / g or more, and less than 1.3m 2 / g, preferably 1m 2 / g or less, more preferably 1.0m 2 / g or less. Since the specific surface area of ​​magnesium oxide is within the above range, it is easy to control the interface between magnesium oxide particles and resin, and it is easy to suppress the increase in viscosity and torque of the mixture when mixed with resin.

[0182] In Scheme II, the preferred specific surface area of ​​magnesium oxide is 1.3 m². 2 / g or more and 10m 2 / g or less, more preferably 1.3m 2 / g or more and 5.0m 2 / g or less, more preferably 1.3m 2 / g or more and 3.0m 2 / g or less. The preferred specific surface area of ​​magnesium oxide is 1.3m². 2 / g or more, and preferably 10m 2 / g or less, preferably 5.0m 2 / g or less, more preferably 3.0m 2 / g or less. Since the specific surface area of ​​magnesium oxide is within the above range, it is easy to control the interface between magnesium oxide particles and resin, and it is easy to suppress the increase in viscosity and torque of the mixture when mixed with resin.

[0183] The preferred specific surface area of ​​magnesium oxide is 0.01 m². 2 / g or more and 10m 2 / g or less, more preferably 0.05m 2 / g or more and 5.0m 2 / g or less, more preferably 0.1m 2 / g or more and 3.0m 2 / g or less. The specific surface area of ​​the above-mentioned magnesium oxide is preferably 0.01m². 2 / g or more, preferably 0.05m 2 / g or more, further preferably 0.1m 2 / g or more, and preferably 10m 2 / g or less, preferably 5.0m2 / g or less, more preferably 3.0m 2 / g or less.

[0184] In this disclosure, the specific surface area can be determined by the BET method, specifically according to JIS Z 8830.

[0185] In Scheme I, the average particle size of magnesium oxide is preferably 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, and even more preferably 1.5 μm or more and 35 μm or less. The average particle size of magnesium oxide is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 35 μm or less. Because the average particle size of magnesium oxide is within the above range, the surface state of magnesium oxide is easily controlled, moisture resistance can be improved, and the viscosity and torque when mixed with resin can be reduced.

[0186] In Scheme II, the average particle size of magnesium oxide is preferably 0.5 μm or more and 10 μm or less, more preferably 1.0 μm or more and 8 μm or less, and even more preferably 1.5 μm or more and 5 μm or less. The average particle size of magnesium oxide is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less. Because the average particle size of magnesium oxide is within the above range, the surface state of magnesium oxide is easily controlled, moisture resistance can be improved, and the viscosity and torque when mixed with resin can be reduced.

[0187] The average particle size of magnesium oxide is preferably 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, and even more preferably 1.5 μm or more and 30 μm or less.

[0188] In this disclosure, the average particle size can be determined by the Microtrac method (laser diffraction scattering method) and can be the median particle size (D50) on a volume basis.

[0189] In Scheme I, magnesium oxide preferably has a specific surface area of ​​0.01 m². 2 / g or more and less than 1.3m 2 / g, with an average particle size of 0.5μm or more and 50μm or less; more preferably, a specific surface area of ​​0.05m². 2 / g or more and 1.3m 2The particle size is less than / g, with an average particle size of 1.0μm or more and 40μm or less; more preferably, the specific surface area is 0.1m². 2 / g or more and 1.0m 2 The particle size is below / g, with an average particle size of 1.5μm or more and below 30μm.

[0190] In Scheme II, magnesium oxide preferably has a specific surface area of ​​1.3 m². 2 / g or more and 10m 2 The particles are less than 1.5 μm in size and have an average particle size of 0.5 μm or more but less than 10 μm; more preferably, the specific surface area is 1.3 m² / g. 2 / g or more and 5.0m 2 The particles are less than 1.0 μm in size and have an average particle size of 1.0 μm or more but less than 8 μm; more preferably, the specific surface area is 1.3 m². 2 / g or more and 3.0m 2 The particles are less than / g and have an average particle size of more than 1.5μm and less than 5μm.

[0191] Magnesium oxide preferably has a specific surface area of ​​0.01 m². 2 / g or more and 10m 2 The particle size is less than / g, with an average particle size of 0.5μm or more and 50μm or less; more preferably, the specific surface area is 0.05m². 2 / g or more and 5m 2 The particle size is less than / g, with an average particle size of 1.0μm or more and 40μm or less; more preferably, the specific surface area is 0.1m². 2 / g or more and 3m 2 The particle size is below / g, with an average particle size of 1.5μm or more and below 30μm.

[0192] In Scheme I, the torque of magnesium oxide measured by the following method is preferably 50 N·m or less, more preferably 45 N·m or less, even more preferably 40 N·m or less, and for example, it can be 10 N·m or more, 15 Pa·s or more, and even more than 20 N·m.

[0193] In Scheme II, the torque of magnesium oxide measured by the following method is preferably 53 N·m or less, more preferably 50 N·m or less, even more preferably 45 N·m or less, and even more preferably 40 N·m or less. For example, it can be 10 N·m or more, 15 Pa·s or more, and even more preferably 20 N·m or more.

[0194] [Methods for measuring torque]

[0195] The ethylene-octene polyolefin resin was heated to 120°C and mixed for 10 minutes. Then, magnesium oxide was added to the ethylene-octene polyolefin resin at a volume ratio of 51:49. The mixture was further mixed at 120°C for 15 minutes, and the torque (N·m) was measured at 30 rpm.

[0196] In this case, in scheme I, magnesium oxide preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (I-1') described later.

[0197] Furthermore, in this case, in scheme II, magnesium oxide preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (II-1') described later.

[0198] In Scheme I, the viscosity of magnesium oxide, as determined by the following method (i), is preferably 70 Pa·s or less, more preferably 67 Pa·s or less, and even more preferably 65 Pa·s or less. For example, it can be 10 Pa·s or more, 15 Pa·s or more, and even 20 Pa·s or more.

[0199] In Scheme II, the viscosity of magnesium oxide, as determined by the following method (i), is preferably 130 Pa·s or less, more preferably 120 Pa·s or less, and even more preferably 110 Pa·s or less. For example, it can be 40 Pa·s or more, 50 Pa·s or more, and even 60 Pa·s or more.

[0200] [Methods for determining viscosity (i)]

[0201] Bisphenol-type epoxy resin and magnesium oxide were mixed at a volume ratio of 70:30. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 25°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0202] In this case, in scheme I, magnesium oxide preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (I-1'') described later.

[0203] Furthermore, in this case, in scheme II, magnesium oxide preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (II-1'') described later.

[0204] In Scheme I, the viscosity of magnesium oxide, as determined by the following method (ii), is preferably 19 Pa·s or less, more preferably 18 Pa·s or less, even more preferably 17 Pa·s or less, for example, it can be 10 Pa·s or more, and even more preferably 15 Pa·s or more.

[0205] In Scheme II, the viscosity of magnesium oxide, as determined by the following method (ii), is preferably 27 Pa·s or less, more preferably 26 Pa·s or less, and even more preferably 25 Pa·s or less. For example, it can be 10 Pa·s or more, 15 Pa·s or more, and even 20 Pa·s or more.

[0206] [Methods for determining viscosity (ii)]

[0207] A multifunctional acrylic monomer was mixed with magnesium oxide at a volume ratio of 60:40. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 23°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0208] In this case, in scheme I, the magnesium oxide of this disclosure preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (I-1'') described later.

[0209] Furthermore, in this case, in scheme II, the magnesium oxide of this disclosure preferably has a surface treatment layer, which is preferably formed using a surface treatment agent containing a silane coupling agent. Such a silane coupling agent preferably comprises a compound represented by formula (1) described later, and more preferably a compound represented by formula (II-1'') described later.

[0210] The magnesium oxide disclosed herein, when mixed with resin, can suppress the increase in torque. Furthermore, the magnesium oxide disclosed herein, when mixed with resin, can also suppress the increase in viscosity. This reduces the load on the manufacturing equipment. Additionally, if the resin material containing magnesium oxide is liquid, its flowability can be improved for injection into sealed areas; if the resin material containing magnesium oxide is solid, improved moldability is expected.

[0211] The magnesium oxide disclosed herein preferably has a surface treatment layer on its surface. That is, the magnesium oxide of this disclosure may be a material comprising MgO and a surface treatment layer disposed on the surface of the MgO. The MgO is preferably MgO particles. The surface treatment layer covers at least a portion of the surface of the MgO, preferably all of it.

[0212] The surface treatment layer described above is preferably formed using a surface treatment agent containing a silane coupling agent.

[0213] Silane coupling agents can be compounds containing hydrolyzable silyl groups and monovalent organic groups. Hydrolyzable silyl groups refer to Si atoms bonded with hydroxyl or hydrolyzable groups.

[0214] The aforementioned hydrolyzable groups refer to groups that can generate silanol groups through hydrolysis. Examples of such hydrolyzable groups include: -OR a1 -OCOR a1 halogens and hydrogen atoms. R a1 C represents 1-4 Alkyl groups, preferably methyl or ethyl.

[0215] The aforementioned monovalent organic group can be a monovalent group containing a carbon atom, or it can be a monovalent hydrocarbon group; or a monovalent or divalent hydrocarbon group can be combined with a group selected from -O-, -CO-, -NR-. a2 -and-SiR a3 A group consisting of one or more of the elements in 2-. R a2 C represents 1-4 Alkyl or hydrogen atom, R a3 C represents 1-6 Hydrocarbon group. A divalent or higher organic group can be a group that uses one or more hydrogen atoms contained in the above-mentioned monovalent organic groups as bonding sites.

[0216] The aforementioned monovalent hydrocarbon group can be a monovalent group containing both carbon and hydrogen, or a group whose bonding site is one hydrogen atom contained in the hydrocarbon compound. Preferably, the aforementioned hydrocarbon group is C. 1-30The hydrocarbon group can be an aliphatic hydrocarbon group; an alicyclic hydrocarbon group; an aromatic hydrocarbon group; or any group composed of two or more of the aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group. The aforementioned aliphatic hydrocarbon group can be either straight-chain or branched, and can be either saturated or unsaturated. A divalent or higher hydrocarbon group can be a group whose bonding site is one or more hydrogen atoms contained in the aforementioned monovalent hydrocarbon group.

[0217] The molecular weight of the aforementioned silane coupling agent is preferably 130 or more and 10,000 or less, more preferably 140 or more and 6,000 or less. The higher the molecular weight of the silane coupling agent, the better the water resistance of the resulting magnesium oxide can be.

[0218] In this disclosure, the molecular weight of silane coupling agents with a molecular weight less than 500 can be calculated based on the structural formula of the silane coupling agent. Furthermore, the molecular weight of silane coupling agents with a molecular weight of 500 or more refers to the weight-average molecular weight, which can be determined by gel permeation chromatography and can be used as a conversion value with polystyrene as a standard sample.

[0219] The aforementioned silane coupling agent preferably comprises a compound represented by the following formula (1):

[0220] R 1 n -S(OR 2 ) m ···(1)

[0221] In formula (1),

[0222] R 1 Each is represented independently -L 1 -R 3 ,

[0223] L 1 Each can independently represent a single bond or a divalent organic group.

[0224] R 3 Each independently represents a selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups,

[0225] R 4 Each represents C independently. 1-6 hydrocarbon group,

[0226] R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom,

[0227] n represents an integer from 1 to 3.

[0228] m represents an integer from 1 to 3.

[0229] R 1 Each is represented independently -L 1 -R 3 .

[0230] L 1 Each can independently represent a single bond or a divalent organic group.

[0231] As L 1 Examples of divalent organic groups include: divalent hydrocarbon groups; or divalent hydrocarbon groups combined with groups selected from -O-, -CO-, and -NR-. a2 and -SiR a3 A group consisting of one or more of the elements in 2-.

[0232] L 1 The preferred option can be represented by the following equations (i) to (iv):

[0233] -R a4 -O-CO- ···(i)

[0234] -R a4 -NR a2 - ···(ii)

[0235] -R a4 -NR a2 -CO-O- ···(iii)

[0236] -R a4 -NR a2 -CO-OR a5 -(OR a6 ) p1 -(OSiR a3 2) p2 - ···(iv)

[0237] In equations (i) to (iv),

[0238] R a2 C represents 1-4 Alkyl or hydrogen atom,

[0239] R a3 C represents 1-6 hydrocarbon group,

[0240] R a4 C represents 1-4 Alkylene

[0241] R a5 C represents 1-4 Alkylene

[0242] R a6C represents 1-4 Alkylene

[0243] p1 represents an integer from 1 to 5.

[0244] p2 represents an integer from 2 to 100.

[0245] In equations (i) to (iv), R is preferred. a4 One end of the side is bonded to the Si atom in formula (1), and the other end is bonded to R. 3 Bonding.

[0246] R a2 C represents 1-4 The alkyl group can be straight-chain or branched, and preferably methyl or ethyl. As R a2 Hydrogen atoms are preferred.

[0247] As R a3 C represents 1-6 Hydrocarbon groups, for example: C 1-6 Alkyl and phenyl groups. The above C 1-6 Alkyl groups can be straight-chain or branched, preferably C14. 1-4 Alkyl, more preferably methyl or ethyl, and even more preferably methyl. As R a3 Methyl or phenyl is preferred.

[0248] R a4 C represents 1-4 Alkyl groups can be straight-chain or branched, preferably C16-26-3 ... 2-3 Alkylene.

[0249] R a5 C represents 1-4 Alkyl groups can be straight-chain or branched, preferably C16-26-3 ... 2-3 Alkylene.

[0250] R a6 C represents 1-4 Alkyl groups can be straight-chain or branched, preferably C16-26-3 ... 2-3 Alkylene.

[0251] p1 represents an integer from 1 to 5, preferably from 1 to 3.

[0252] p2 represents an integer from 2 to 100, preferably from 5 to 80, and more preferably from 10 to 70.

[0253] As L 1 Preferably, it is a single bond or a group represented by formula (i), (ii), (iii), (iv), and more preferably a single bond or a group represented by formula (i), (ii), (iv).

[0254] R3 Indicates selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 In one of the three options, the preferred option in a given scheme can be selected from C. 1-30 Alkyl and C 2-30 One of the alkenyl groups, in another embodiment, is preferably selected from C. 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0255] R 3 C represents 1-30 The alkyl group can be straight-chain or branched, preferably branched. The above C 1-30 Alkyl groups are preferably straight-chain or branched C4 groups. 1-30 Alkyl groups, more preferably straight-chain or branched C4 groups 5-25 Alkyl groups, more preferably straight-chain or branched C4 groups. 10-20 Alkyl groups, more preferably branched C4 groups 10-20 alkyl.

[0256] R 3 C represents 2-30 The alkenyl group can be linear or branched. The above C 2-30 The alkenyl group is preferably a straight-chain or branched C group. 2-15 Alkenyl groups, more preferably linear or branched C groups, are preferred. 2-10 Alkenyl groups, more preferably linear or branched C groups 2-7 Alkenyl groups, more preferably linear or branched C groups, are preferred. 2-4 Alkenyl group.

[0257] R 3 C represents 6-30 The aromatic hydrocarbon group can be monocyclic or polycyclic, preferably monocyclic. The above C 6-30 The aromatic hydrocarbon group is preferably a monocyclic or polycyclic C. 6-20 Aromatic hydrocarbon groups, more preferably monocyclic or polycyclic C groups. 6-15 Aromatic hydrocarbon groups, more preferably monocyclic or polycyclic C groups. 6-10 Aromatic hydrocarbon groups, more preferably monocyclic C 6-8 Aromatic hydrocarbon group. As R 3 Examples of aromatic hydrocarbon groups that can be represented include: phenyl, tolyl, xylyl, styryl, and naphthyl.

[0258] As R 4 C represents 1-6 Hydrocarbon groups, for example: C 1-6 Alkyl and phenyl groups. The above C 1-6 Alkyl groups can be straight-chain or branched, preferably C14.1-4 Alkyl, more preferably methyl or ethyl, and even more preferably methyl. As R 4 Methyl or phenyl is preferred.

[0259] In one scheme, as R 3 Preferred selection from C 1-30 Alkyl, C 2-30 alkenyl and -SiR 4 One of the three groups.

[0260] In another scheme, as R 3 Preferred selection from C 1-30 Alkyl and C 2-30 One of the alkenyl groups.

[0261] In yet another proposal, as R 3 Preferred selection from C 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups.

[0262] In yet another proposal, as R 3 Preferred selection from C 1-30 Alkyl and -SiR 4 One of the three groups.

[0263] R 2 Each represents C independently. 1-4 Alkyl group or hydrogen atom. R 2 C represents 1-4 The alkyl group can be straight-chain or branched, and preferably methyl or ethyl. As R 2 Preferably, it is selected from one or more of methyl, ethyl and hydrogen atoms.

[0264] n can represent an integer from 1 to 3, preferably 1 or 2, and more preferably 1.

[0265] m can represent an integer from 1 to 3, preferably 2 or 3, and more preferably 3.

[0266] In one embodiment, the silane coupling agent preferably comprises a compound represented by the following formula (I-1'):

[0267] R 1 n -S(OR 2 ) m ... (I-1')

[0268] In formula (I-1'),

[0269] R 1 Each is represented independently -L 1 -R 3I' ,

[0270] L 1 Each can independently represent a single bond or a divalent organic group.

[0271] R 3I' Each independently represents a selection from C 1-30 Alkyl and C 2-30 One of the alkenyl groups,

[0272] R 4 Each represents C independently. 1-6 hydrocarbon group,

[0273] R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom,

[0274] n represents an integer from 1 to 3.

[0275] m represents an integer from 1 to 3.

[0276] In another embodiment, the aforementioned silane coupling agent preferably comprises a compound represented by the following formula (I-1''):

[0277] R 1 n -S(OR 2 ) m ... (I-1'')

[0278] In formula (I-1''),

[0279] R 1 Each is represented independently -L 1 -R 3I'' ,

[0280] L 1 Each can independently represent a single bond or a divalent organic group.

[0281] R 3I'' Each independently represents a selection from C 2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups,

[0282] R 4 Each represents C independently. 1-6 hydrocarbon group,

[0283] R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom,

[0284] n represents an integer from 1 to 3.

[0285] m represents an integer from 1 to 3.

[0286] In yet another embodiment, the aforementioned silane coupling agent preferably comprises a compound represented by the following formula (II-1'):

[0287] R 1 n -Si-(OR 2 ) m ... (II-1')

[0288] In formula (II-1'),

[0289] R 1 Each is represented independently -L 1 -R 3II' ,

[0290] L 1 Each can independently represent a single bond or a divalent organic group.

[0291] R 3II' Each independently represents a selection from C 1-30 Alkyl and -SiR 4 One of the three groups,

[0292] R 4 Each represents C independently. 1-6 hydrocarbon group,

[0293] R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom,

[0294] n represents an integer from 1 to 3.

[0295] m represents an integer from 1 to 3.

[0296] In another embodiment, the aforementioned silane coupling agent may preferably comprise a compound represented by the following formula (II-1''):

[0297] R 1 n -Si-(OR 2 ) m ···(II-1'')

[0298] In formula (II-1''),

[0299] R 1 Each is represented independently -L 1 -R 3II'' ,

[0300] L 1 Each can independently represent a single bond or a divalent organic group.

[0301] R 3II'' Each independently represents a selection from C2-30 alkenyl and C 6-30 One of the aromatic hydrocarbon groups,

[0302] R 4 Each represents C independently. 1-6 hydrocarbon group,

[0303] R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom,

[0304] n represents an integer from 1 to 3.

[0305] m represents an integer from 1 to 3.

[0306] As the aforementioned silane coupling agent, commercially available products or synthetic products can be used.

[0307] In the above surface treatment agent, the content of the compound represented by formula (1) in 100% by mass of silane coupling agent is preferably 80% or more and 100% or less by mass, more preferably 90% or more and 100% or less by mass, and even more preferably 95% or more and 100% or less by mass.

[0308] In the above-mentioned surface treatment agent, the content of silane coupling agent in 100% by mass of the surface treatment agent is preferably 80% or more and 100% or less by mass, more preferably 90% or more and 100% or less by mass, and even more preferably 95% or more and 100% or less by mass.

[0309] In addition to silane coupling agents, the surface treatment agents mentioned above may also contain water and catalysts. The catalysts can be either acid catalysts or base catalysts. Examples of acid catalysts include nitric acid, sulfuric acid, and acetic acid, while examples of base catalysts include ammonia.

[0310] In Scheme I, the value of r in the aforementioned magnesium oxide is represented by the following equation (2). s Preferably, it is 100% or more and 4,000% or less.

[0311] [Number 3]

[0312]

[0313] In formula (2),

[0314] n s Indicates the amount of substance (mol) of the silane coupling agent.

[0315] N A Avogadro's constant (mol) -1 ),

[0316] S s This represents the area occupied by one molecule of silane coupling agent (m²). 2 ),

[0317] m m This indicates the amount of magnesium oxide added (g).

[0318] s m The specific surface area of ​​magnesium oxide (m²) 2 ·g -1 ).

[0319] In scheme I, the above r s Preferably, it is 100% or more and 4,000% or less, more preferably 100% or more and 3,500% or less, and even more preferably 100% or more and 3,000% or less. s Preferably, it is 100% or more, more preferably 4,000% or less, more preferably 3,500% or less, and even more preferably 3,000% or less. By making the above r... s If the lower limit is within the above range, it is expected to increase the contact probability between the surface treatment agent and the magnesium oxide surface, thus promoting the surface treatment reaction. On the other hand, by making the above r s Within the aforementioned range, the amount of silane coupling agent added is moderate relative to the surface area of ​​magnesium oxide, which can suppress manufacturing costs and maintain thermal conductivity even when mixed with resin, thereby also suppressing exudation.

[0320] In Scheme II, the aforementioned r s Preferably, it is 40% or more and 500% or less, more preferably 40% or more and 400% or less, and even more preferably 40% or more and 300% or less. s Preferably, it is 40% or more, more preferably 500% or less, more preferably 400% or less, and even more preferably 300% or less. By making the above r... s If the lower limit is within the above range, it is expected to increase the contact probability between the surface treatment agent and the magnesium oxide surface, thus promoting the surface treatment reaction. On the other hand, by making the above r s Within the aforementioned range, the amount of silane coupling agent added is moderate relative to the surface area of ​​magnesium oxide, which can suppress manufacturing costs and maintain thermal conductivity even when mixed with resin, thereby also suppressing exudation.

[0321] The above r s Preferably, it is 40% or more and 210% or less, more preferably 50% or more and 200% or less, and even more preferably 70% or more and 150% or less. sPreferably, it is 40% or more, more preferably 50% or more, even more preferably 70% or more, and preferably 210% or less, even more preferably 200% or less, and even more preferably 150% or less.

[0322] The above r s This can also be described as the ratio of the total area that the silane coupling agent can cover to the surface area of ​​the MgO that will be treated. By making r s If the lower limit is within the above range, the coverage of MgO by the silane coupling agent can be improved. Furthermore, by making r... s If the upper limit is within the above range, it is easy to improve the coverage efficiency of silane coupling agents.

[0323] The area occupied by the aforementioned 1 molecule of silane coupling agent can be calculated based on the area occupied by the SO- groups bonded to MgO, for example, it can be set as 13 × 10⁻⁶. -20 (m) 2 ).

[0324] Magnesium oxide with the above-mentioned surface treatment layer can be manufactured by wet processing.

[0325] Specifically, the method for manufacturing magnesium oxide is also included within the scope of this disclosure. The method includes the following steps: surface-treating a first magnesium oxide with a surface treatment agent containing a silane coupling agent to obtain a second magnesium oxide having a surface-treated layer.

[0326] The surface treatment described above is performed using a wet process.

[0327] It is believed that by performing the above surface treatment through wet processing, the silane coupling agent can be uniformly attached to the MgO surface.

[0328] In this disclosure, wet processing can refer to processing a mixture comprising the object to be surface-treated and a surface-treated agent in a slurry state. The slurry may be, for example, a mixture with a solids content of 10% by mass or more and 70% by mass or less, preferably 20% by mass or more and 65% by mass or less, and more preferably 30% by mass or more and 60% by mass or less.

[0329] In this disclosure, the solid component of the mixture refers to the heating residue after heating the mixture at 105°C for 1 hour, and the solid component concentration refers to the value obtained by dividing the total mass of the heating residue by the total mass of the mixture supplied for heating.

[0330] The surface treatment agents containing silane coupling agents mentioned above have the same meaning as the surface treatment agents used to form the surface treatment layer mentioned above.

[0331] The aforementioned first magnesium oxide can typically be magnesium oxide without a surface treatment layer, i.e., MgO.

[0332] In Scheme I, the specific surface area of ​​the first magnesium oxide can be 0.01 m². 2 / g or more and less than 1.3m 2 / g, preferably 0.05m 2 / g or more and 1m 2 / g or less, more preferably 0.1m 2 / g or more and 1.0m 2 / g or less. The specific surface area of ​​magnesium oxide can be 0.01m². 2 / g or more, preferably 0.05m 2 / g or more, more preferably 0.1m 2 / g or more, and can be less than 1.3m 2 / g, preferably 1m 2 / g or less, more preferably 1.0m 2 / g or less. By keeping the specific surface area of ​​the first magnesium oxide within the above range, the interface between the magnesium oxide particles forming the surface treatment layer and the resin can be easily controlled, and the viscosity of the mixture can be reduced when mixed with the resin.

[0333] In Scheme II, the specific surface area of ​​the first magnesium oxide can preferably be 0.01 m². 2 / g or more and 10m 2 / g or less, more preferably 0.05m 2 / g or more and 5.0m 2 / g or less, more preferably 0.1m 2 / g or more and 3.0m 2 / g or less. The specific surface area of ​​magnesium oxide is preferably 0.01m². 2 / g or more, preferably 0.05m 2 / g or more, further preferably 0.1m 2 / g or more, and preferably 10m 2 / g or less, preferably 5.0m 2 / g or less, more preferably 3.0m 2 / g or less.

[0334] The specific surface area of ​​magnesium oxide can preferably be 0.01 m². 2 / g or more and 10m 2 / g or less, more preferably 0.05m 2 / g or more and 5.0m 2 / g or less, more preferably 0.1m 2 / g or more and 3.0m 2 / g or less. The specific surface area of ​​the first magnesium oxide described above is preferably 0.01m². 2 / g or more, preferably 0.05m 2 / g or more, further preferably 0.1m 2 / g or more, and preferably 10m 2 / g or less, preferably 5.0m 2 / g or less, more preferably 3.0m 2 / g or less.

[0335] In Scheme I, the average particle size of the first magnesium oxide is preferably 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, and even more preferably 1.5 μm or more and 35 μm or less. The average particle size of the first magnesium oxide is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 35 μm or less. Because the average particle size of the first magnesium oxide is within the above range, the surface state of the magnesium oxide is easily controlled, the resulting magnesium oxide particles with a surface treatment layer exhibit good moisture resistance, and the viscosity and torque when the magnesium oxide is mixed with the resin can be reduced.

[0336] In Scheme II, the average particle size of the first magnesium oxide is preferably 0.5 μm or more and 10 μm or less, more preferably 1.0 μm or more and 8 μm or less, and even more preferably 1.5 μm or more and 5 μm or less. The average particle size of the first magnesium oxide is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less.

[0337] The average particle size of the first magnesium oxide is preferably 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, and even more preferably 1.5 μm or more and 30 μm or less. The average particle size of the first magnesium oxide is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less.

[0338] The above-mentioned surface treatment agent can be used to achieve the r expressed by the above formula (2). s It is preferably used in an amount of 40% or more and 210% or less, more preferably 50% or more and 200% or less, and even more preferably 70% or more and 150% or less.

[0339] In a preferred embodiment, the manufacturing method described above may include the following steps:

[0340] The organic solvent was mixed with the first magnesium oxide to obtain the first mixture;

[0341] The surface treatment agent containing the silane coupling agent is mixed with the first mixture to obtain the second mixture;

[0342] The organic solvent was removed from the second mixture to obtain the second magnesium oxide precursor;

[0343] The above-mentioned second magnesium oxide precursor is heated and / or dried to obtain a second magnesium oxide with a surface treatment layer.

[0344] As the aforementioned organic solvent, an organic solvent that can be miscible with or can dissolve the silane coupling agent is preferred.

[0345] The boiling point of the aforementioned organic solvent is preferably 70°C or higher and 140°C or lower, more preferably 75°C or higher and 130°C or lower, and even more preferably 80°C or higher and 120°C or lower. By keeping the boiling point of the organic solvent within this range, the surface treatment exhibits good stability, and subsequent heating and / or drying of the precursor can be easily performed.

[0346] As the organic solvents mentioned above, alcohol solvents are preferred, specifically ethanol, isopropanol and butanol.

[0347] In the first mixture described above, the amount of organic solvent relative to 100 parts by mass of the first magnesium oxide is preferably 50 parts by mass or more and 900 parts by mass or less, more preferably 60 parts by mass or more and 400 parts by mass or less, and even more preferably 70 parts by mass or more and 200 parts by mass or less.

[0348] The first mixture may also contain water. The amount of water relative to 100 parts by mass of the organic solvent contained in the first mixture is preferably 0 parts by mass or more and 10 parts by mass or less, more preferably 0.01 parts by mass or more and 5 parts by mass or less, and even more preferably 0.05 parts by mass or more and 3 parts by mass or less.

[0349] When the first mixture contains water, the mixing order of the organic solvent, the first magnesium oxide, and the water is not particularly limited. For example, the organic solvent can be mixed with water first, and then the mixture can be further mixed with magnesium oxide; the organic solvent can be mixed with magnesium oxide first, and then the mixture can be further mixed with water; or the organic solvent, water, and magnesium oxide can be mixed simultaneously.

[0350] The mixing of the aforementioned organic solvent with magnesium oxide can be carried out, for example, by stirring and / or ultrasonic treatment. Furthermore, the stirring treatment can be carried out using a magnetic stirrer or a mechanical stirrer. Using a magnetic stirrer, stirring is easily controlled; using a mechanical stirrer, even with a high viscosity mixture, uniform mixing can be achieved. During the stirring treatment, baffles can be installed in the stirring tank. Installing baffles improves stirring efficiency. Furthermore, ultrasonic treatment can break up any agglomerates of magnesium oxide, resulting in a more homogeneous mixture.

[0351] The preparation of the first mixture can be carried out under conditions where the temperature of the first mixture is preferably 10°C or higher and 40°C or lower, more preferably 15°C or higher and 30°C or lower.

[0352] The surface treatment agents containing silane coupling agents mentioned above have the same meaning as the surface treatment agents used to form the surface treatment layer mentioned above.

[0353] In scheme I, the above-mentioned surface treatment agent can be such that r represents the above formula (2). s Preferably, it is used in an amount of 100% or more and 4,000% or less, more preferably 100% or more and 3,500% or less, and even more preferably 100% or more and 3,000% or less. Furthermore, the above-mentioned surface treatment agent can be used in an amount such that r s Preferably, it is used in an amount of 100% or more, more preferably 4,000% or less, more preferably 3,500% or less, and even more preferably 3,000% or less. By making the above-mentioned r s If the lower limit is within the above range, it is expected to increase the contact probability between the surface treatment agent and the magnesium oxide surface, thus promoting the surface treatment reaction. On the other hand, by making the above r s Within the aforementioned range, the amount of silane coupling agent added is moderate relative to the surface area of ​​magnesium oxide, which can suppress manufacturing costs and maintain thermal conductivity even when mixed with resin, thereby also suppressing exudation.

[0354] In scheme II, the above-mentioned surface treatment agent can be used such that r represents the above formula (2). s Preferably, it is used in an amount of 100% or more and 500% or less, more preferably 100% or more and 400% or less, and even more preferably 100% or more and 300% or less. Furthermore, the above-mentioned surface treatment agent can be used to achieve a concentration such that r s Preferably, it is used in an amount of 100% or more, more preferably 500% or less, more preferably 400% or less, and even more preferably 300% or less. By making the above r s If the lower limit is within the above range, it is expected to increase the contact probability between the surface treatment agent and the magnesium oxide surface, thus promoting the surface treatment reaction. On the other hand, by making the above r sWithin the aforementioned range, the amount of silane coupling agent added is moderate relative to the surface area of ​​magnesium oxide, which can suppress manufacturing costs and maintain thermal conductivity even when mixed with resin, thereby also suppressing exudation.

[0355] The above-mentioned surface treatment agent can be used to achieve the r expressed by the above formula (2). s It is preferably used in an amount of 40% or more and 210% or less, more preferably 50% or more and 200% or less, and even more preferably 70% or more and 150% or less.

[0356] Before mixing the surface treatment agent with the first mixture, the first solution can be allowed to stand for a certain period of time. It is believed that this operation makes it easier for the organic solvent and the first magnesium oxide to be mixed evenly.

[0357] The mixing of the surface treatment agent and the first mixture can be carried out by the stirring and / or ultrasonic treatment. It is believed that by carrying out the mixing by stirring and / or ultrasonic treatment, a more uniform mixture can be achieved, and a more uniform surface treatment layer can be formed in the resulting second magnesium oxide.

[0358] The preparation of the second mixture can be carried out at a temperature above the melting point of the silane coupling agent and below the boiling point of the organic solvent. Specifically, it is preferable to carry out the preparation at a temperature above 10°C and below 40°C, and more preferably at a temperature above 15°C and below 30°C. It is believed that by mixing the surface treatment agent with the first mixture at such a temperature, more uniform stirring can be achieved, and a more uniform surface treatment layer can be formed in the resulting second magnesium oxide.

[0359] Methods for removing organic solvents from the second mixture include, for example, filtration, distillation, centrifugation, and freeze-drying. Filtration allows for efficient removal of organic solvents. Distillation easily removes only the organic solvents. Centrifugation removes organic solvents even if the second mixture has a high viscosity due to its high separation ability between solids and liquids. Freeze-drying effectively suppresses the agglomeration of magnesium oxide.

[0360] The temperature for heating and / or drying the obtained magnesium oxide precursor is not particularly limited, as long as it is below the decomposition temperature of the solvent and the silane coupling agent. The temperature for heating and / or drying the magnesium oxide precursor is preferably 80°C or higher and 250°C or lower, more preferably 100°C or higher and 220°C or lower, and even more preferably 120°C or higher and 200°C or lower. Furthermore, the time for heating and / or drying the magnesium oxide precursor is preferably 30 minutes or higher and 48 hours or lower, more preferably 1 hour or higher and 24 hours or lower. By heating and / or drying the precursor under these conditions, the reaction between the silane coupling agent and magnesium oxide can be promoted, forming a surface treatment layer.

[0361] The aforementioned heating and / or drying can be carried out using, for example, a hot air dryer, a microwave dryer, or a rotary dryer. Hot air dryers are highly versatile and can efficiently perform heating and drying. Rotary dryers are suitable for efficiently heating and drying large quantities of precursors. Microwave dryers do not require a high-temperature heat source, thus easily reducing energy consumption.

[0362] The magnesium oxide disclosed herein can be manufactured by a method different from the manufacturing method in the above embodiments, and the manufacturing method of magnesium oxide disclosed herein is not limited to providing only the magnesium oxide described above.

[0363] The aforementioned magnesium oxide is preferably used as a thermally conductive material, particularly a heat dissipation filler. The heat dissipation filler is used to mix with resin materials, rubber materials, etc., to form heat dissipation components. Examples of the aforementioned resin materials include: thermoplastic resins such as polyolefin resins, polyamide resins, and polyphenylene sulfide resins; epoxy resins; phenolic resins; silicone resins; urea-formaldehyde resins; melamine resins; and thermosetting resins such as unsaturated polyesters. Examples of the aforementioned rubber materials include: silicone rubber, butyl rubber, butadiene rubber, acrylic rubber, ethylene propylene rubber, polyurethane rubber, and polyurethane rubber silicone resin.

[0364] In a composition comprising magnesium oxide and resin and / or rubber materials, the volume ratio of magnesium oxide to the total volume of the resin and / or rubber materials and magnesium oxide (magnesium oxide / (resin and / or rubber materials + magnesium oxide)) is preferably 1 or more and 90 or less, more preferably 5 or more and 60 or less, and even more preferably 10 or more and 50 or less.

[0365] In Scheme I, the torque of the above composition, as measured by the following method, is preferably 50 N·m or less, more preferably 45 N·m or less, and even more preferably 40 N·m or less. For example, it can be 10 N·m or more, 15 Pa·s or more, and even 20 N·m or more.

[0366] In Scheme II, the torque of the above composition, as measured by the following method, is preferably 53 N·m or less, more preferably 50 N·m or less, even more preferably 45 N·m or less, and even more preferably 40 N·m or less. For example, it can be 10 N·m or more, 15 Pa·s or more, and even more preferably 20 N·m or more.

[0367] [Methods for measuring torque]

[0368] The ethylene-octene polyolefin resin was heated to 120°C and mixed for 10 minutes. Then, magnesium oxide was added to the ethylene-octene polyolefin resin at a volume ratio of 51:49. The mixture was further mixed at 120°C for 15 minutes, and the torque (N·m) was measured at 30 rpm.

[0369] In Scheme I, the viscosity of the above composition, as determined by the following method (i), is preferably 70 Pa·s or less, more preferably 67 Pa·s or less, and even more preferably 65 Pa·s or less. For example, it can be 10 Pa·s or more, 15 Pa·s or more, and even 20 Pa·s or more.

[0370] In Scheme II, the viscosity of the above composition, as determined by the following method (i), is preferably 130 Pa·s or less, more preferably 120 Pa·s or less, and even more preferably 110 Pa·s or less. For example, it can be 40 Pa·s or more, 50 Pa·s or more, and even 60 Pa·s or more.

[0371] [Methods for determining viscosity (i)]

[0372] Bisphenol-type epoxy resin and magnesium oxide were mixed at a volume ratio of 70:30. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 25°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0373] In Scheme I, the viscosity of the above composition, as determined by the following method (ii), is preferably 19 Pa·s or less, more preferably 18 Pa·s or less, even more preferably 17 Pa·s or less, for example, it can be 10 Pa·s or more, and further preferably 15 Pa·s or more.

[0374] In Scheme II, the viscosity of the above composition, as determined by the following method (ii), is preferably 27 Pa·s or less, more preferably 26 Pa·s or less, and even more preferably 25 Pa·s or less. For example, it can be 10 Pa·s or more, 15 Pa·s or more, and even 20 Pa·s or more.

[0375] [Methods for determining viscosity (ii)]

[0376] A multifunctional acrylic monomer was mixed with magnesium oxide at a volume ratio of 60:40. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used, employing a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm, at a temperature of 23°C, a gap distance of 1 mm, and a shear rate range of 0–20 s. -1 Viscosity (Pa·s) was measured under the condition of a measurement time of 20 seconds.

[0377] The aforementioned multifunctional acrylic monomers can be compounds having two or more (meth)acryloyl groups in one molecule. Examples include: ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and other difunctional (meth)acrylic monomers; trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, and other trifunctional (meth)acrylic monomers. Among them, (meth)acrylic monomers with more than 3 functions are preferred, and pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate are more preferred.

[0378] The molecular weight of the multifunctional acrylic monomer is preferably 150 or more and 800 or less, more preferably 250 or more and 400 or less.

[0379] The magnesium oxide disclosed herein, when mixed with resin, can suppress the increase in torque or viscosity. This could potentially reduce the load on the apparatus during the manufacture of resin compositions or heat dissipation materials, while simultaneously improving the moldability of resin materials containing magnesium oxide.

[0380] In such heat dissipation components, the aforementioned magnesium oxide can be used alone as a heat dissipation filler, or it can be used in combination with one or more other fillers selected from metal hydroxides, metal oxides, and metal nitrides. The heat dissipation filler and other fillers used in the heat dissipation components may or may not undergo surface treatment. That is, these heat dissipation fillers and other fillers may or may not have a surface treatment layer. Furthermore, the shape and particle size of the aforementioned heat dissipation filler and other fillers are not particularly limited. Because the heat dissipation filler using the magnesium oxide of this disclosure undergoes wet processing, in addition to improved durability (thermal conductivity retention) of the heat dissipation component, it becomes easier to mix with resin (viscosity / torque during mixing is reduced), thereby allowing for large-volume filling / mixing. As a result, the load on the device during manufacturing can be reduced, and thermal conductivity can be improved.

[0381] Examples of heat dissipation components include: heat sinks, heat dissipation pads, phase change plates, heat dissipation tapes, heat dissipation gap fillers, heat dissipation adhesives, heat dissipation greases, and sealing materials; and heat dissipation substrates such as heat dissipation insulating sheets and ceramic-based circuit boards. These TIM materials and heat dissipation substrates can be used in automobiles (especially inverters, ECUs, LiB circuits, etc.), mobile devices such as smartphones, communication equipment, communication base stations, electrical products (especially inverters), and LED devices.

[0382] Furthermore, the aforementioned magnesium oxide can also be used as a filler in composites. This filler is used to mix with resins and other additives to form composites. Examples of such resins include: polyolefin resins, polyamide resins, thermoplastic resins such as polyphenylene sulfide resins, epoxy resins, phenolic resins, silicone resins, urea-formaldehyde resins, melamine resins, and thermosetting resins such as unsaturated polyesters.

[0383] Example

[0384] The present disclosure is illustrated in more detail by way of the following embodiments, but the present disclosure is not limited to these embodiments.

[0385] (Synthesis Example 1: Silane Coupling Agent A)

[0386] 22.5 parts by weight of 3-isocyanatopropyltriethoxysilane and 45.3 parts by weight of 1-dodecanool (TCI) were added to a 100 mL round-bottom flask and stirred at 60 °C for 6 hours to obtain silane coupling agent A with alkyl-terminated chains. (Molecular weight (MW) 433)

[0387] (Synthesis Example 2: Silane Coupling Agent B)

[0388] 22.5 parts by weight of 3-isocyanatopropyltriethoxysilane and 45.3 parts by weight of 2-butyloctanol (TCI) were added to a 100 mL round-bottom flask and stirred at 60 °C for 6 hours to obtain silane coupling agent B with alkyl-terminated chains. (Molecular weight (MW) 433)

[0389] (Synthesis Example 3: Silane Coupling Agent C)

[0390] 10.3 parts by weight of 3-isocyanatopropyltriethoxysilane and 50.0 parts by weight of Silaplane FM-0411 (manufactured by JNC, a dimethyl polysiloxane with OH-terminated ends, Mn1000) were added to a 100 mL round-bottom flask. The mixture was stirred at 60 °C for 6 hours to obtain silane coupling agent C with alkyl-terminated ends. (Weight average molecular weight (MW) 1247)

[0391] (Synthesis Example 4: Silane Coupling Agent D)

[0392] 2.6 parts by weight of 3-isocyanatopropyltriethoxysilane and 50.0 parts by weight of Silaplane FM-0421 (manufactured by JNC, a dimethyl polysiloxane with OH-terminated ends, Mn5000) were added to a 100 mL round-bottom flask. The mixture was stirred at 60 °C for 6 hours to obtain silane coupling agent D with alkyl-terminated ends. (Weight average molecular weight (MW) 5247)

[0393] (Example I-1)

[0394] 400 parts by weight of isopropanol and 200 parts by weight of magnesium oxide (B) were added to a 1L round-bottom flask and stirred at 30°C and 800 rpm for 1 hour. While maintaining stirring, 0.3 parts by weight of silane coupling agent A were added, and stirring was continued for another hour under the same conditions. After stirring, the isopropanol was removed, yielding magnesium oxide with a surface covered by the silane coupling agent. The obtained magnesium oxide was then heated in a dryer at 120°C for 6 hours to undergo a curing reaction, thus completing the preparation of surface-coated magnesium oxide via a wet method.

[0395] (r) s : 136%, Particle size (D50) of surface-treated magnesium oxide: 24.1 μm, Specific surface area of ​​surface-treated magnesium oxide: 0.2 m² 2 / g)

[0396] (Examples I-2 to I-8, Comparative Examples I-3 and I-5)

[0397] Magnesium oxide with surface coating was prepared by wet method according to the same procedures as in Example I-1, following the compositions in Tables 1 and 2 respectively.

[0398] In Tables 1 and 2, magnesium oxide (A) represents a specific surface area of ​​1.6 m². 2Magnesium oxide with an average particle size of 2.5 μm and a surface area of ​​0.2 m² / g, where magnesium oxide (B) represents a specific surface area of ​​0.2 m² / g. 2 / g, magnesium oxide with an average particle size of 25μm. IPA stands for isopropanol.

[0399] Silane coupling agent E represents dodecyltriethoxysilane, silane coupling agent F represents octadecyltriethoxysilane, silane coupling agent G represents vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBE-1003), silane coupling agent H represents 3-methacryloyloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBE-503), silane coupling agent I represents decyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-3103C), silane coupling agent J represents N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-573), and silane coupling agent K represents 3-epoxypropoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-403).

[0400] (Comparative Examples I-1 and I-2)

[0401] Magnesium oxide without surface treatment was used.

[0402] (Comparative Example I-4)

[0403] 200 parts by weight of magnesium oxide (B) were placed in a Henschel mixer, and 0.2 parts by weight of silane coupling agent I were gradually added while stirring. After the addition was completed, the mixture was heated at 150°C for 30 minutes, and magnesium oxide with a completed surface coating was obtained by a dry method.

[0404] The magnesium oxide obtained in the examples and comparative examples of Scheme I was evaluated using the following methods.

[0405] (Particle size determination)

[0406] The measurements were performed using a MicrotracBEL MT3300EXII laser diffraction / scattering particle size distribution analyzer. Ethanol was used as the solvent. As a pretreatment, ethanol was mixed with the sample, and the sample was dispersed in the ethanol by ultrasonic treatment.

[0407] (Specific surface area measurement)

[0408] The measurements were performed using the MicrotracBEL BELsorp-max specific surface area / pore distribution measuring device.

[0409] (Dyne value)

[0410] As solutions with known dyne values, wetting tension test mixtures No. 25.4, No. 30.0, No. 35.0, No. 40.0, No. 45.0, and No. 50.0 (manufactured by Fujifilm and Koko Pure Chemical Industries, Ltd.) and water were prepared. 0.01 parts by weight of magnesium oxide prepared in the examples and comparative examples were added to 2 mL of each liquid adjusted to 25°C. The lowest dyne value at which all added particles floated on the liquid surface was taken as the dyne value of the surface-coated magnesium oxide.

[0411] (Moisture resistance test)

[0412] 3.0 g of sample was placed in a weighing bottle and placed in a constant temperature and humidity chamber at 85℃ and 85% for one week. The weight change before and after the experiment was measured. To make a lateral comparison of particles with different particle sizes and specific surface areas, the value obtained by dividing the weight change rate by the specific surface area was also recorded.

[0413] [Table 1]

[0414]

[0415] [Table 2]

[0416]

[0417] Examples I-1 to I-8 are embodiments of Scheme 1, and good moisture resistance was confirmed.

[0418] Comparative examples I-1 to I-2 and I-4 to I-5 all have dyne values ​​of 45 mN / m or higher, and their moisture resistance does not fully meet the requirements.

[0419] Comparative examples I-1 and I-3 have a specific surface area of ​​1.3 m². 2 For examples with a moisture resistance of / g or higher, the moisture resistance does not fully meet the requirements.

[0420] (Example I-9)

[0421] 24 parts by weight of ENGAGE 8200 (manufactured by DOW, ethylene-octene polyolefin resin, MFR: 5 g / 10 min, Mooney viscosity (121°C): 8 MU, glass transition temperature: -53°C) were added to a plasticorder manufactured by Brabender, and the mixture was heated to 120°C and kneaded for 10 minutes to soften the resin. 96 parts by weight of magnesium oxide obtained in Example 3 were added to the softened resin and kneaded for 15 minutes to prepare a resin composition with dispersed MgO. The torque after 15 minutes of kneading was taken as the torque of the resin composition.

[0422] (Example I-10, Comparative Examples I-6 and I-7)

[0423] In Example 9, the same procedure as in Example 9 was followed, except that magnesium oxide as shown in Table 3 was used instead of the magnesium oxide obtained in Example 3, to obtain a resin composition, and the torque was measured.

[0424] [Table 3]

[0425]

[0426] Examples I-9 and I-10 are embodiments of Scheme I, in which the torque of the mixture after mixing with the resin is suppressed.

[0427] Comparative Example I-6 is magnesium oxide with a dyne value exceeding 50 mN / m and a specific surface area of ​​1.3 m². 2 In examples with a volume of / g or higher, the torque of the mixture after being mixed with the resin was not adequately suppressed.

[0428] Comparative Example I-7 is an example where the dyne value of magnesium oxide exceeds 50 mN / m, and the torque of the mixture after being mixed with the resin is not sufficiently suppressed.

[0429] (Example I-11)

[0430] Add 25 parts by weight of jER-828 (manufactured by Mitsubishi Chemical, bisphenol A type epoxy resin, viscosity at 25°C: 12-15 Pa·s, epoxy equivalent: 184-194 g / eq) and 33 parts by weight of magnesium oxide prepared in Example 3 to a 50 mL glass bottle, and stir at 25°C and 500 rpm for 1 hour to obtain a resin composition in which magnesium oxide is dispersed.

[0431] The viscosity of the obtained resin composition was measured. Specifically, a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm were installed in a rheometer (MCR series) manufactured by Anton Paar Japan. The viscosity was measured under the following conditions, and the viscosity was evaluated in 1 second. -1 viscosity.

[0432] Measurement conditions

[0433] Measurement mode: Continuous slope measurement

[0434] Temperature: 25℃

[0435] Gap distance: 1mm

[0436] Shear rate measurement range: 0–20 s -1

[0437] Measurement time: 20s

[0438] (Example I-12, Comparative Examples I-8 to I-10)

[0439] In Examples I-11, the resin compositions were obtained in the same manner as in Example 11, except that the magnesium oxide shown in Table 4 was used instead of the magnesium oxide obtained in Examples I-3. The viscosity of the obtained resin compositions was measured under the same conditions as in Example 11.

[0440] [Table 4]

[0441]

[0442] Examples I-11 and I-12 are embodiments of Scheme 1, in which the viscosity is suppressed when mixed with resin.

[0443] Comparative Example I-8 is magnesium oxide with a dyne value of 50 mN / m or higher and a specific surface area of ​​1.3 m². 2 In examples with a viscosity of / g or higher, the viscosity of the mixture after mixing with the resin was not adequately suppressed.

[0444] Comparative Example I-9 is an example where the dyne value of magnesium oxide is 50 mN / m or higher, and the viscosity of the mixture after mixing with the resin is not sufficiently suppressed.

[0445] Comparative Example I-10 has a specific surface area of ​​1.3 m². 2 In examples with a viscosity of / g or higher, the viscosity of the mixture after mixing with the resin was not adequately suppressed.

[0446] (Example I-13)

[0447] Ten parts by weight of the multifunctional acrylic monomer Aronix M-306 (manufactured by Toa Synthetic Co., Ltd., multifunctional acrylic monomer, viscosity at 25°C: 0.45–0.75 Pa·s) and 20.3 parts by weight of the magnesium oxide prepared in Example 3 were added to a 50 mL glass bottle. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition in which magnesium oxide was dispersed. The volume ratio of the multifunctional acrylic monomer to magnesium oxide was 60:40.

[0448] The viscosity of the obtained resin composition was measured. Specifically, a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm were installed in a rheometer (MCR series) manufactured by Anton Paar Japan. The viscosity was measured under the following conditions, and the viscosity was evaluated in 1 second. -1 viscosity.

[0449] Measurement conditions

[0450] Measurement mode: Continuous slope measurement

[0451] Temperature: 23℃

[0452] Gap distance: 1mm

[0453] Shear rate measurement range: 0–20 s -1

[0454] Measurement time: 20s

[0455] (Examples I-13 to I-15, Comparative Examples I-11 to I-13)

[0456] In Examples I-11, the resin composition was obtained by operating in the same manner as in Examples I-11, except that the magnesium oxide shown in Table 5 was used instead of the magnesium oxide obtained in Examples I-3. The viscosity of the obtained resin composition was measured under the same conditions as in Examples I-11.

[0457] [Table 5]

[0458]

[0459] Examples I-13, I-14, and I-15 are examples of Scheme I, in which viscosity is suppressed when mixed with resin.

[0460] Comparative Example I-11 has a magnesium oxide dyne value of 50 mN / m or higher and a specific surface area of ​​1.3 m². 2 In examples with a viscosity of / g or higher, the viscosity of the mixture after mixing with the resin was not adequately suppressed.

[0461] Comparative Example I-12 is an example where the dyne value of magnesium oxide is above 50 mN / m, and the viscosity of the mixture after mixing with the resin is not sufficiently suppressed.

[0462] Comparative Example I-13 has a specific surface area of ​​1.3 m². 2 In examples with a viscosity of / g or higher, the viscosity of the mixture after mixing with the resin was not adequately suppressed.

[0463] (Examples II-1 to II-15, Comparative Examples II-2 and II-7)

[0464] Magnesium oxide coatings were prepared by wet method according to the compositions in Tables 6 and 7, following the same procedures as in Example I-1.

[0465] In Tables 6 and 7, magnesium oxide (A) represents a specific surface area of ​​1.6 m². 2 / g, magnesium oxide with an average particle size of 2.5μm. IPA represents isopropanol.

[0466] Furthermore, silane coupling agent E represents dodecyltriethoxysilane, silane coupling agent F represents octadecyltriethoxysilane, silane coupling agent G represents vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBE-1003), silane coupling agent H represents 3-methacryloyloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBE-503), silane coupling agent I represents decyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-3103C), silane coupling agent J represents N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-573), and silane coupling agent K represents 3-epoxypropoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-403).

[0467] (Comparative Example II-1)

[0468] Magnesium oxide without surface treatment was used.

[0469] (Comparative Example II-3)

[0470] 200 parts by weight of magnesium oxide (A) were placed in a Henschel mixer, and 1.8 parts by weight of silane coupling agent A were gradually added while stirring. After the addition was completed, the mixture was heated at 150°C for 30 minutes, and the surface-coated magnesium oxide was obtained by a dry method.

[0471] (Comparative Examples II-4 to II-6)

[0472] Magnesium oxide coatings were prepared by dry method according to the composition in Table 7 and the same process as Comparative Example II-3.

[0473] The magnesium oxide obtained in the examples and comparative examples was evaluated using the following methods.

[0474] (Particle size determination)

[0475] The particle size distribution was measured using a MicrotracBEL MT3300EXII laser diffraction / scattering particle size distribution analyzer. Ethanol was used as the solvent. As a pretreatment before measurement, the ethanol was mixed with the sample, and the sample was dispersed in the ethanol by ultrasonic treatment.

[0476] (Specific surface area measurement)

[0477] The measurements were performed using the BELsorp-max specific surface area / pore size distribution measuring device manufactured by MicrotracBEL.

[0478] (Dyne value)

[0479] As solutions with known dyne values, wetting tension test mixtures No. 25.4, No. 30.0, No. 35.0, No. 40.0, No. 45.0, and No. 50.0 (manufactured by Fujifilm and Koko Pure Chemical Industries, Ltd.) and water were prepared. 0.01 parts by weight of magnesium oxide prepared in the examples and comparative examples were added to 2 mL of each liquid adjusted to 25°C. The lowest dyne value at which all added particles floated on the liquid surface was taken as the dyne value of the surface-coated magnesium oxide.

[0480] (Moisture resistance test)

[0481] 3.0 g of sample was placed in a weighing bottle and placed in a constant temperature and humidity chamber at 85℃ and 85% for one week. The weight change before and after the experiment was measured. To make a lateral comparison of particles with different particle sizes and specific surface areas, the value obtained by dividing the weight change rate by the specific surface area was also recorded.

[0482] [Table 6]

[0483]

[0484] [Table 7]

[0485]

[0486] Examples II-1 to II-16 are embodiments of Scheme II, confirming good moisture resistance.

[0487] Comparative Examples II-1 to II-7 are all examples with a dyne value of 45 mN / m or higher, and their moisture resistance does not fully meet the requirements.

[0488] (Example II-17)

[0489] 24 parts by weight of ENGAGE 8200 (manufactured by DOW, ethylene-octene polyolefin resin, MFR: 5 g / 10 min, Mooney viscosity (121°C): 8 MU, glass transition temperature: -53°C) were added to a plasticorder manufactured by Brabender, and the mixture was heated to 120°C and kneaded for 10 minutes to soften the resin. 96 parts by weight of magnesium oxide obtained in Example II-1 were added to the softened resin and kneaded for 15 minutes to prepare a resin composition dispersed with MgO. The torque after 15 minutes of kneading was taken as the torque of the resin composition.

[0490] (Example II-18, Comparative Examples II-8 to II-9)

[0491] In Example 17, the same procedure was followed as in Example 17, except that magnesium oxide as shown in Table 8 was used instead of the magnesium oxide obtained in Example II-1, to obtain a resin composition and measure the torque.

[0492] [Table 8]

[0493]

[0494] Examples II-17 and II-18 are embodiments of Scheme II, in which the torque of the mixture after mixing with the resin is suppressed.

[0495] Comparative Examples II-8 and II-9 are examples of magnesium oxide with a dyne value of 45 mN / m or higher, and the torque of the mixture after mixing with the resin was not sufficiently suppressed.

[0496] (Example II-19)

[0497] 25 parts by weight of jER-828 (manufactured by Mitsubishi Chemical, bisphenol A type epoxy resin, viscosity at 25°C: 12-15 Pa·s, epoxy equivalent: 184-194 g / eq) and 33 parts by weight of magnesium oxide prepared in Examples II-7 were added to a 50 mL glass bottle and stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition in which magnesium oxide is dispersed.

[0498] The viscosity of the obtained resin composition was measured. Specifically, a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm were installed in a rheometer (MCR series) manufactured by Anton Paar Japan. The viscosity was measured under the following conditions, and the viscosity was evaluated in 1 second. -1 viscosity.

[0499] Measurement conditions

[0500] Measurement mode: Continuous slope measurement

[0501] Temperature: 25℃

[0502] Gap distance: 1mm

[0503] Shear rate measurement range: 0–20 s -1

[0504] Measurement time: 20s

[0505] (Examples II-20 to II-21, Comparative Examples II-10 to II-12)

[0506] In Example II-19, the resin composition was obtained by operating in the same manner as in Example II-19, except that the magnesium oxide shown in Table 9 was used instead of the magnesium oxide obtained in Example II-7. The viscosity of the obtained resin composition was measured under the same conditions as in Example II-19.

[0507] [Table 9]

[0508]

[0509] Examples II-19 to II-21 are examples of Scheme II, in which the viscosity is suppressed when mixed with resin.

[0510] Comparative Examples II-10 to II-12 are examples of magnesium oxide with a dyne value of 45 mN / m or higher, and the viscosity of the mixture after mixing with the resin was not sufficiently suppressed.

[0511] (Example II-22)

[0512] Ten parts by weight of the multifunctional acrylic monomer Aronix M-306 (manufactured by Toa Synthetic Co., Ltd., multifunctional acrylic monomer, viscosity at 25°C: 0.45–0.75 Pa·s) and 20.3 parts by weight of the magnesium oxide prepared in Examples II-7 were added to a 50 mL glass bottle. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition in which magnesium oxide was dispersed. The volume ratio of the multifunctional acrylic monomer to magnesium oxide was 60:40.

[0513] The viscosity of the obtained resin composition was measured. Specifically, a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm were installed in a rheometer (MCR series) manufactured by Anton Paar Japan. The viscosity was measured under the following conditions, and the viscosity was evaluated in 1 second. -1 viscosity.

[0514] Measurement conditions

[0515] Measurement mode: Continuous slope measurement

[0516] Temperature: 23℃

[0517] Gap distance: 1mm

[0518] Shear rate measurement range: 0–20 s -1

[0519] Measurement time: 20s

[0520] (Examples II-22 to II-24, Comparative Examples II-13 to II-15)

[0521] In Example II-22, the resin composition was obtained by operating in the same manner as in Example II-22, except that the magnesium oxide shown in Table 10 was used instead of the magnesium oxide obtained in Example II-7. The viscosity of the obtained resin composition was measured under the same conditions as in Example II-22.

[0522] [Table 10]

[0523]

[0524] Examples II-22 to II-24 are examples of Scheme II, in which the viscosity is suppressed when mixed with resin.

[0525] Comparative Examples II-13 to II-15 are examples of magnesium oxide with a dyne value of 45 mN / m or higher, and the viscosity of the mixture after mixing with the resin was not sufficiently suppressed.

[0526] Industrial practicality

[0527] The magnesium oxide of this invention is preferably used as a thermally conductive material, and particularly preferably as a heat-dissipating filler. The heat-dissipating filler can be mixed with resin materials, rubber, etc., to form heat-dissipating components.

[0528] Examples of heat dissipation components include: heat sinks, heat dissipation pads, phase change plates, heat dissipation tapes, heat dissipation gap fillers, heat dissipation adhesives, heat dissipation greases, and sealing materials (TIM materials, thermal interface materials); and heat dissipation substrates such as heat dissipation insulating sheets and ceramic-based circuit boards. These TIM materials and heat dissipation substrates can be used in: automobiles (especially inverters, ECUs, LiB boards, etc.), mobile devices such as smartphones, communication equipment, communication base stations, electrical products (especially inverters), and LED devices.

Claims

1. A magnesium oxide having a dyne value of less than 50 mN / m and a specific surface area of ​​0.01 m². 2 / g or more and less than 1.3m 2 / g.

2. The magnesium oxide according to claim 1, wherein the average particle size is 0.5 μm or more and 50 μm or less.

3. The magnesium oxide according to claim 1 or 2, having a surface treatment layer formed using a surface treatment agent containing a silane coupling agent.

4. The magnesium oxide according to claim 3, wherein, The silane coupling agent comprises a compound represented by the following formula (1): R 1 n -S(OR 2 ) m ···(1) In equation (1), R 1 Each is represented independently -L 1 -R 3 , L 1 Each can independently represent a single bond or a divalent organic group. R 3 Each independently represents a selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, R 4 Each represents C independently. 1-6 hydrocarbon group, R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom, n represents an integer from 1 to 3. m represents an integer from 1 to 3.

5. The magnesium oxide according to claim 3 or 4, wherein, The value r is represented by the following equation (2). s Between 100% and 4,000%, In equation (2), n s Indicates the amount of substance (mol) of the silane coupling agent. N A Avogadro's constant (mol) -1 ), S s This represents the area occupied by one molecule of silane coupling agent (m²). 2 ), m m This indicates the amount of magnesium oxide added (g). s m The specific surface area of ​​magnesium oxide (m²) 2 ·g -1 ).

6. A magnesium oxide having a torque of less than 50 N·m as determined by the following method. The method for measuring torque is as follows: The ethylene-octene polyolefin resin was heated to 120°C and mixed for 10 minutes. Then, magnesium oxide was added to the ethylene-octene polyolefin resin at a volume ratio of 51:

49. The mixture was further mixed at 120°C for 15 minutes. The torque was measured at 30 rpm, and the unit of torque was N·m.

7. The magnesium oxide according to claim 6, wherein it has a surface treatment layer formed using a surface treatment agent containing a silane coupling agent. The silane coupling agent comprises a compound represented by the following formula (1): R 1 n -S(OR 2 ) m ···(1) In equation (1), R 1 Each is represented independently -L 1 -R 3 , L 1 Each can independently represent a single bond or a divalent organic group. R 3 Each independently represents a selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, R 4 Each represents C independently. 1-6 hydrocarbon group, R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom, n represents an integer from 1 to 3. m represents an integer from 1 to 3.

8. A magnesium oxide having a viscosity of less than 70 Pa·s, as determined by the following method. The method for measuring viscosity is as follows: Bisphenol-type epoxy resin and magnesium oxide were mixed at a volume ratio of 70:

30. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used with a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm to measure the shear rate in the range of 0–20 s at 25°C and a gap distance of 1 mm. -1 Viscosity was measured under a 20-second measurement period, and the unit of viscosity is Pa·s.

9. The magnesium oxide according to claim 8, wherein it has a surface treatment layer formed using a surface treatment agent containing a silane coupling agent. The silane coupling agent comprises a compound represented by the following formula (1): R 1 n -S(OR 2 ) m ···(1) In equation (1), R 1 Each is represented independently -L 1 -R 3 , L 1 Each can independently represent a single bond or a divalent organic group. R 3 Each independently represents a selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, R 4 Each represents C independently. 1-6 hydrocarbon group, R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom, n represents an integer from 1 to 3. m represents an integer from 1 to 3.

10. A magnesium oxide having a viscosity of less than 19 Pa·s, as determined by the following method. The method for measuring viscosity is as follows: Multifunctional acrylic monomers and magnesium oxide were mixed at a volume ratio of 60:

40. The mixture was stirred at 25°C and 500 rpm for 1 hour to obtain a resin composition. A rheometer was used with a disposable parallel plate with a diameter of 25 mm and a disposable cup with a diameter of 80 mm to measure the shear rate at a temperature of 23°C, a gap distance of 1 mm, and a range of 0–20 s. -1 Viscosity was measured under a 20-second measurement period, and the unit of viscosity is Pa·s.

11. The magnesium oxide according to claim 10, wherein it has a surface treatment layer formed using a surface treatment agent containing a silane coupling agent. The silane coupling agent comprises a compound represented by the following formula (1): R 1 n -S(OR 2 ) m ···(1) In equation (1), R 1 Each is represented independently -L 1 -R 3 , L 1 Each can independently represent a single bond or a divalent organic group. R 3 Each independently represents a selection from C 1-30 Alkyl, C 2-30 alkenyl, C 6-30 Aromatic hydrocarbon groups and -SiR 4 One of the three groups, R 4 Each represents C independently. 1-6 hydrocarbon group, R 2 Each represents C independently. 1-4 Alkyl or hydrogen atom, n represents an integer from 1 to 3. m represents an integer from 1 to 3.

12. A method for manufacturing magnesium oxide, comprising surface treating a first magnesium oxide with a surface treatment agent containing a silane coupling agent to obtain a second magnesium oxide having a surface-treated layer. in, The surface treatment is performed by a wet process.

13. The method for producing magnesium oxide according to claim 12, wherein, The surface treatment is carried out by a process including the following steps: The organic solvent was mixed with the first magnesium oxide to obtain the first mixture; The surface treatment agent is mixed with the first mixture to obtain the second mixture; The organic solvent is removed from the second mixture to obtain the second magnesium oxide precursor; as well as The second magnesium oxide precursor is heated and / or dried to obtain a second magnesium oxide with a surface treatment layer.

14. A heat dissipation component comprising magnesium oxide according to any one of claims 1 to 11.

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