JP2014214222A - Thermally-conductive filler and production method thereof and resin composition - Google Patents
Thermally-conductive filler and production method thereof and resin composition Download PDFInfo
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- 239000011231 conductive filler Substances 0.000 title claims abstract description 104
- 239000011342 resin composition Substances 0.000 title claims abstract description 26
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims abstract description 50
- 239000000395 magnesium oxide Substances 0.000 claims abstract description 45
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims abstract description 45
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims abstract description 45
- 238000002156 mixing Methods 0.000 claims abstract description 44
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052796 boron Inorganic materials 0.000 claims abstract description 34
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims abstract description 25
- 235000019341 magnesium sulphate Nutrition 0.000 claims abstract description 25
- 229920005989 resin Polymers 0.000 claims abstract description 18
- 239000011347 resin Substances 0.000 claims abstract description 18
- 150000001639 boron compounds Chemical class 0.000 claims abstract description 15
- 239000000203 mixture Substances 0.000 claims abstract description 14
- 238000010304 firing Methods 0.000 claims description 19
- 239000002904 solvent Substances 0.000 claims description 5
- 238000004090 dissolution Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 12
- 230000036571 hydration Effects 0.000 abstract description 8
- 238000006703 hydration reaction Methods 0.000 abstract description 8
- 238000001354 calcination Methods 0.000 abstract description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 25
- 239000004327 boric acid Substances 0.000 description 23
- 238000000034 method Methods 0.000 description 18
- 239000000945 filler Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 239000002245 particle Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 239000012752 auxiliary agent Substances 0.000 description 7
- 238000007580 dry-mixing Methods 0.000 description 7
- 239000000835 fiber Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- QLZJUIZVJLSNDD-UHFFFAOYSA-N 2-(2-methylidenebutanoyloxy)ethyl 2-methylidenebutanoate Chemical compound CCC(=C)C(=O)OCCOC(=O)C(=C)CC QLZJUIZVJLSNDD-UHFFFAOYSA-N 0.000 description 4
- 229910021538 borax Inorganic materials 0.000 description 4
- 229920006244 ethylene-ethyl acrylate Polymers 0.000 description 4
- 239000005042 ethylene-ethyl acrylate Substances 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000004898 kneading Methods 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- 239000004328 sodium tetraborate Substances 0.000 description 4
- 235000010339 sodium tetraborate Nutrition 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 3
- 238000013329 compounding Methods 0.000 description 3
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 3
- 239000000347 magnesium hydroxide Substances 0.000 description 3
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OHVLMTFVQDZYHP-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CN1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O OHVLMTFVQDZYHP-UHFFFAOYSA-N 0.000 description 1
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
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- 239000011248 coating agent Substances 0.000 description 1
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- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 150000002681 magnesium compounds Chemical class 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
Abstract
Description
本発明は、熱伝導性フィラー及びその製造方法並びに樹脂組成物に関し、特に、酸化マグネシウムを主成分とする熱伝導性フィラー及びその製造方法並びに樹脂組成物に関する。 The present invention relates to a thermally conductive filler, a method for producing the same, and a resin composition, and particularly relates to a thermally conductive filler mainly composed of magnesium oxide, a method for producing the same, and a resin composition.
酸化マグネシウムは、熱伝導性や耐熱性などに優れた無機化合物であり、樹脂組成物の熱伝導性を高めるための熱伝導性フィラーとして様々な樹脂に使用されている。 Magnesium oxide is an inorganic compound excellent in thermal conductivity and heat resistance, and is used in various resins as a thermally conductive filler for increasing the thermal conductivity of the resin composition.
例えば、特許文献1には、塩基性硫酸マグネシウムを焼成して得られる、長さ/直径比が約5以上の繊維状酸化マグネシウムであって、樹脂の熱伝導率改良剤の用途として用いられることが記載されている。また、特許文献2には、マグネシウム及び結晶水を含有する針状粒子を焼成して得られる繊維状酸化マグネシウムであって、合成樹脂用充填剤として用いられることが記載されている。熱伝導性フィラーは隣り合うフィラー同士の接触により熱伝導パス(経路)が形成されて熱を効率よく伝達するが、従来の柱状(又は針状)の熱伝導性フィラーはアスペクト比が大きく熱伝導性フィラーの長手方向において熱伝導効率が高いため、アスペクト比が低いものに比べて樹脂組成物の熱伝導率が向上する。
For example, in
柱状酸化マグネシウムからなる熱伝導性フィラーは、硫酸や水を含む柱状マグネシウム化合物を焼成することで製造される。しかしながら、上述した従来の熱伝導性フィラーは、焼成時に劣化しやすいため、必ずしも望ましい柱状にならないことがあった。 The thermally conductive filler made of columnar magnesium oxide is produced by firing a columnar magnesium compound containing sulfuric acid and water. However, the above-described conventional thermally conductive filler is not necessarily formed into a desirable column shape because it easily deteriorates during firing.
具体的には、ウィスカー状の塩基性硫酸マグネシウムは、焼成によって硫酸根や水が抜けて内部に空洞が多くなり、このため焼成後の柱状酸化マグネシウムは脆くて崩れやすくなる。したがって、アスペクト比の高い熱伝導性フィラーを得ることが困難であり、従来はアスペクト比の低いものしか得られにくかった。また、このようなアスペクト比の低い熱伝導性フィラーを配合した樹脂組成物は、アスペクト比の高い熱伝導性フィラーを使用した場合と比較して、同じ配合量あたりの熱伝導率が低くなりがちであった。さらに、熱伝導率を高くするために樹脂に対して熱伝導性フィラーの配合割合を多くすると、製造コストがかかったり、樹脂の特性に悪影響を与えたりするという不都合もあった。 Specifically, whisker-like basic magnesium sulfate is baked to remove sulfate radicals and water, resulting in a large number of cavities in the inside. For this reason, post-baked columnar magnesium oxide is brittle and easily collapses. Therefore, it is difficult to obtain a heat conductive filler having a high aspect ratio, and it has conventionally been difficult to obtain only a low aspect ratio. In addition, a resin composition containing such a low aspect ratio thermal conductive filler tends to have a lower thermal conductivity per the same amount compared to the case where a high aspect ratio thermal conductive filler is used. Met. Furthermore, if the blending ratio of the heat conductive filler is increased with respect to the resin in order to increase the heat conductivity, there are disadvantages in that the manufacturing cost is increased and the properties of the resin are adversely affected.
また、アスペクト比の低い熱伝導性フィラーは、アスペクト比の高い熱伝導性フィラーよりも比表面積が高いため、表面からの水分吸収量が増加することから耐水和性に劣っていた。このため、このようなアスペクト比の低い熱伝導性フィラーを配合した樹脂組成物もまた耐水性に劣るものとなっていた。 Moreover, since the specific surface area of the heat conductive filler with a low aspect ratio is higher than that of the heat conductive filler with a high aspect ratio, the amount of moisture absorbed from the surface is increased, resulting in poor hydration resistance. For this reason, the resin composition which mix | blended such a heat conductive filler with a low aspect ratio was also inferior to water resistance.
本発明の目的は、アスペクト比が高く耐水和性に優れた柱状の熱伝導性フィラー及びその製造方法を提供することにある。また、本発明の他の目的は、熱伝導率が高く耐水性にも優れた樹脂組成物を提供することにある。 An object of the present invention is to provide a columnar heat conductive filler having a high aspect ratio and excellent hydration resistance, and a method for producing the same. Another object of the present invention is to provide a resin composition having high thermal conductivity and excellent water resistance.
本発明者らは、以上の目的を達成するために、鋭意検討した結果、柱状の酸化マグネシウムとホウ素を含有することで、アスペクト比が高く耐水和性にも優れた熱伝導性フィラーを提供できることを見出して、本発明を完成させるに至った。 As a result of intensive investigations to achieve the above object, the present inventors can provide a thermally conductive filler having a high aspect ratio and excellent hydration resistance by containing columnar magnesium oxide and boron. As a result, the present invention has been completed.
すなわち、本発明は、柱状酸化マグネシウム及びホウ素を少なくとも含み、長径/短径で定義されるアスペクト比の平均値が2以上であることを特徴とする熱伝導性フィラーである。 That is, the present invention is a thermally conductive filler characterized in that it contains at least columnar magnesium oxide and boron, and has an average aspect ratio defined by major axis / minor axis of 2 or more.
この場合において、前記ホウ素の含有量が、B2O3換算で0.1〜1.0重量%であることが好ましい。 In this case, the boron content is preferably 0.1 to 1.0% by weight in terms of B 2 O 3 .
また、平均長径が1.0〜10.0μmであることが好ましい。 Moreover, it is preferable that an average major axis is 1.0-10.0 micrometers.
さらに、前記ホウ素は、前記柱状酸化マグネシウムの表面を覆うように付着して前記柱状酸化マグネシウムに含有されていると好適である。 Furthermore, it is preferable that the boron is included so as to cover the surface of the columnar magnesium oxide and is included in the columnar magnesium oxide.
また、本発明は、上記のいずれかに記載の熱伝導性フィラーの製造方法であって、ウィスカー状の塩基性硫酸マグネシウムとホウ素又はホウ素化合物とを混合する混合工程と、前記混合後の混合物を500〜1300℃で焼成する焼成工程と、を含むことを特徴とする熱伝導性フィラーの製造方法である。 Further, the present invention is a method for producing a thermally conductive filler according to any one of the above, wherein a mixing step of mixing whisker-like basic magnesium sulfate and boron or a boron compound, and a mixture after the mixing are performed. And a firing step of firing at 500 to 1300 ° C.
この場合において、前記混合工程は、前記ホウ素又はホウ素化合物を溶媒に溶解し、前記塩基性硫酸マグネシウムを前記溶解後の前記溶媒に混合する湿式混合工程であることが好ましい。 In this case, the mixing step is preferably a wet mixing step of dissolving the boron or boron compound in a solvent and mixing the basic magnesium sulfate with the solvent after dissolution.
さらに、本発明は、柱状酸化マグネシウム及びホウ素を少なくとも含み、長径/短径で定義されるアスペクト比の平均値が2以上である熱伝導性フィラーを酸化マグネシウム換算で1〜60体積%、樹脂を40〜99体積%含有することを特徴とする熱伝導性樹脂組成物である。 Furthermore, the present invention includes a thermally conductive filler containing at least columnar magnesium oxide and boron and having an average aspect ratio defined by major axis / minor axis of 2 or more, 1 to 60% by volume in terms of magnesium oxide, and resin. It is a heat conductive resin composition characterized by containing 40 to 99 volume%.
本発明によれば、アスペクト比が高く耐水和性に優れた柱状の熱伝導性フィラー及びその製造方法を提供することができる。また、本発明によれば、熱伝導率が高く耐水性にも優れた樹脂組成物を提供することができる。 According to the present invention, it is possible to provide a columnar thermally conductive filler having a high aspect ratio and excellent hydration resistance, and a method for producing the same. In addition, according to the present invention, it is possible to provide a resin composition having high thermal conductivity and excellent water resistance.
<熱伝導性フィラー>
本発明の熱伝導性フィラー(以下、単に「熱伝導性フィラー」という)は、柱状酸化マグネシウム及びホウ素を少なくとも含み、長径/短径で定義されるアスペクト比の平均値が2以上である。
<Thermal conductive filler>
The thermally conductive filler of the present invention (hereinafter simply referred to as “thermally conductive filler”) contains at least columnar magnesium oxide and boron, and has an average aspect ratio defined by a major axis / minor axis of 2 or more.
熱伝導性フィラーは、柱状酸化マグネシウムとホウ素を少なくとも含んでいる。柱状の酸化マグネシウムの表面には凹凸が、内部には空洞が多く含まれており、その表面にホウ素が付着している。 The thermally conductive filler contains at least columnar magnesium oxide and boron. The surface of the columnar magnesium oxide has irregularities and many cavities inside, and boron adheres to the surface.
柱状酸化マグネシウムの含有量は、熱伝導性フィラーの全重量を100重量%としたときに、90重量%以上が好ましく、95重量%以上がより好ましく、98重量%以上が特に好ましい。柱状酸化マグネシウムの含有量が90重量%を下回ると、熱伝導性フィラーの熱伝導率が低くなりやすい。 The content of the columnar magnesium oxide is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 98% by weight or more when the total weight of the thermally conductive filler is 100% by weight. When the content of columnar magnesium oxide is less than 90% by weight, the thermal conductivity of the thermally conductive filler tends to be low.
ホウ素の含有量は、B2O3換算で0.1〜1.0重量%の範囲内が好ましく、0.2〜0.9重量%の範囲内がより好ましく、0.3〜0.8重量%の範囲内が特に好ましい。ホウ素の含有量が0.1重量%を下回ると熱伝導性フィラーが脆くなり上記のような高い平均アスペクト比になりにくく、1.0重量%を上回ると酸化マグネシウムに対するホウ酸の割合が高くなるため熱伝導性フィラーの熱伝導率が低くなりやすくなる。ここでいうホウ素の含有量とは、熱伝導性フィラーの全重量を100重量%としたときに、熱伝導性フィラーに含まれるホウ素の割合(重量基準)を意味する。 The boron content is preferably in the range of 0.1 to 1.0% by weight in terms of B 2 O 3 , more preferably in the range of 0.2 to 0.9% by weight, and 0.3 to 0.8%. Particularly preferred is in the range of% by weight. When the boron content is less than 0.1% by weight, the thermally conductive filler becomes brittle and it is difficult to achieve the high average aspect ratio as described above, and when it exceeds 1.0% by weight, the ratio of boric acid to magnesium oxide increases. Therefore, the thermal conductivity of the thermally conductive filler tends to be low. Here, the boron content means the proportion (weight basis) of boron contained in the thermally conductive filler when the total weight of the thermally conductive filler is 100% by weight.
熱伝導性フィラーの平均長径は、好ましくは1.0〜10.0μmの範囲内であり、より好ましくは2.4〜4.0μmの範囲内であり、さらに好ましくは2.5〜3.8μm、特に好ましくは2.7〜3.6μmである。平均長径が1.0μm下回ると熱伝導率が低くなりやすくなり、平均長径が10.0μmを超えると熱伝導性フィラーが折れやすくなる。 The average major axis of the thermally conductive filler is preferably in the range of 1.0 to 10.0 μm, more preferably in the range of 2.4 to 4.0 μm, and even more preferably 2.5 to 3.8 μm. Particularly preferably, it is 2.7 to 3.6 μm. When the average major axis is less than 1.0 μm, the thermal conductivity tends to be low, and when the average major axis exceeds 10.0 μm, the thermal conductive filler tends to break.
熱伝導性フィラーの平均長径のばらつきとしては、特に制限はないが、平均長径の変動係数が30%以下であることが好ましく、20%以下であることがより好ましいく、10%以下であることが特に好ましい。なお、平均長径の変動係数とは、平均長径に対する平均長径の標準偏差の比で表すことができる。 The variation of the average major axis of the thermally conductive filler is not particularly limited, but the coefficient of variation of the average major axis is preferably 30% or less, more preferably 20% or less, and 10% or less. Is particularly preferred. The variation coefficient of the average major axis can be represented by the ratio of the standard deviation of the average major axis to the average major axis.
熱伝導性フィラーのアスペクト比の平均値(以下、「平均アスペクト比」ということがある)は、2以上であり、好ましくは3〜20であり、より好ましくは4〜10である。平均アスペクト比が2を下回ると熱伝導パスが短くなるため、熱伝導率が低くなりやすくなるほか、形状が球状に近くなることから比表面積が増加して表面からの水分の吸収量が多くなるため、耐水和性に劣りやすくなる。また、平均アスペクト比の上限は特に制限はないが、20を超えると熱伝導性フィラーが折れやすくなる。なお、ここでいうアスペクト比とは、長径/短径で定義したものであり、平均値とは複数の熱伝導性フィラーのアスペクト比を平均した値を意味する。 The average aspect ratio (hereinafter sometimes referred to as “average aspect ratio”) of the thermally conductive filler is 2 or more, preferably 3 to 20, and more preferably 4 to 10. When the average aspect ratio is less than 2, the heat conduction path is shortened, so that the heat conductivity is likely to be low, and the shape is close to a spherical shape, so that the specific surface area increases and the amount of moisture absorbed from the surface increases. Therefore, it tends to be inferior in hydration resistance. The upper limit of the average aspect ratio is not particularly limited, but if it exceeds 20, the thermally conductive filler is likely to break. The aspect ratio here is defined by the major axis / minor axis, and the average value means a value obtained by averaging the aspect ratios of a plurality of thermally conductive fillers.
熱伝導性フィラーの平均短径は、上記の平均アスペクト比の範囲内に含まれるものであれば特には限定されない。平均短径の具体例としては、0.3〜0.8μmが好ましく、0.4〜0.7μmがより好ましい。 The average minor axis of the thermally conductive filler is not particularly limited as long as it is within the range of the above average aspect ratio. As a specific example of the average minor axis, 0.3 to 0.8 μm is preferable, and 0.4 to 0.7 μm is more preferable.
熱伝導性フィラーの平均短径のばらつきとしては、特に制限はないが、平均短径の変動係数が30%以下であることが好ましく、20%以下であることがより好ましいく、10%以下であることが特に好ましい。 The variation of the average minor axis of the heat conductive filler is not particularly limited, but the coefficient of variation of the average minor axis is preferably 30% or less, more preferably 20% or less, and 10% or less. It is particularly preferred.
なお、上記の平均長径、平均短径、平均アスペクト比は、熱伝導性フィラーの走査型電子顕微鏡(SEM)写真を目視又は自動的に画像処理する方法で得ることができる。熱伝導性フィラーの長径は、熱伝導性フィラーを立方体とみなしたときの長手方向の長さ(長辺の長さ)として測定することができる。また、熱伝導性フィラーの短径は、熱伝導性フィラーを立方体と見立てたときの短手方向の長さ(短辺の長さ)として測定することができる。さらに、「平均」とは、統計学上の信頼性のある個数(N数)の熱伝導性フィラーを測定して得られた平均値を意味し、その個数としては通常は10個以上、好ましくは50個以上、より好ましくは100個以上である。 In addition, said average major axis, average minor axis, and average aspect-ratio can be obtained by the method of visually or automatically image-processing the scanning electron microscope (SEM) photograph of a heat conductive filler. The major axis of the thermally conductive filler can be measured as the length in the longitudinal direction (long side length) when the thermally conductive filler is regarded as a cube. Moreover, the short diameter of a heat conductive filler can be measured as the length (short side length) of a transversal direction when a heat conductive filler is regarded as a cube. Furthermore, the “average” means an average value obtained by measuring a statistically reliable number (N number) of thermally conductive fillers, and the number is usually 10 or more, preferably Is 50 or more, more preferably 100 or more.
熱伝導性フィラーのBET比表面積は、特に限定されないが、通常、1.0〜5.0m2/gであり、好ましくは1.5〜4.5m2/gであり、より好ましくは2.0〜4.0m2/gである。BET比表面積が1.0m2/gを下回ると、融着、凝集をおこしやすくなり、5.0m2/gを上回ると表面積が大きくなりすぎて耐水和性に劣りやすくなる。 Although the BET specific surface area of a heat conductive filler is not specifically limited, Usually, it is 1.0-5.0 m < 2 > / g, Preferably it is 1.5-4.5 m < 2 > / g, More preferably, it is 2. It is 0-4.0m < 2 > / g. When the BET specific surface area is less than 1.0 m 2 / g, fusion and aggregation tend to occur, and when it exceeds 5.0 m 2 / g, the surface area becomes too large and the hydration resistance tends to be poor.
熱伝導性フィラーとしては、その他の元素や化合物を含んでもよく、例えば酸化物換算で、CaO、SiO2、Al2O3、Fe2O3、Na2SO4などを含んでもよい。 The thermally conductive filler may contain other elements or compounds, for example, in terms of oxide, CaO, SiO 2, Al 2 O 3, Fe 2 O 3, may include such Na 2 SO 4.
<熱伝導性フィラーの製造方法>
上記の熱伝導性フィラーは、原料である塩基性硫酸マグネシウムとホウ素又はホウ素化合物とを混合する混合工程と、混合後の混合物を焼成する焼成工程と、を経ることで製造することができる。以下、本発明の熱伝導性フィラーの製造方法について説明する。
<Method for producing thermally conductive filler>
Said heat conductive filler can be manufactured through the mixing process which mixes the basic magnesium sulfate which is a raw material, and a boron, or a boron compound, and the baking process which bakes the mixture after mixing. Hereinafter, the manufacturing method of the heat conductive filler of this invention is demonstrated.
(1)原料・助剤
原料である塩基性硫酸マグネシウムは、化学式がMgSO4・5Mg(OH)2・3H2Oで表される化合物であり、形状がウィスカー状(針状、繊維状ともいう)である。塩基性硫酸マグネシウムは、平均繊維長が5〜50μm、平均繊維径が0.1〜1.0μm、繊維長/繊維径で定義されるアスペクト比の平均値(平均アスペクト比)が2〜50のものが好ましい。塩基性硫酸マグネシウムの平均アスペクト比が2を下回ると、得られる熱伝導性フィラーの平均アスペクト比も低くなり、熱伝導率や耐水和性が劣るものとなりやすい。また、塩基性硫酸マグネシウムの平均アスペクト比が50を上回るものは、製造自体が困難である。
(1) Raw material / auxiliary material Basic magnesium sulfate, which is a raw material, is a compound represented by the chemical formula MgSO 4 .5Mg (OH) 2 .3H 2 O, and has a whisker shape (also called a needle shape or a fiber shape). ). Basic magnesium sulfate has an average fiber length of 5 to 50 μm, an average fiber diameter of 0.1 to 1.0 μm, and an average aspect ratio (average aspect ratio) defined by fiber length / fiber diameter of 2 to 50. Those are preferred. When the average aspect ratio of basic magnesium sulfate is less than 2, the average aspect ratio of the resulting heat conductive filler is also low, and the thermal conductivity and hydration resistance tend to be poor. Moreover, when the average aspect ratio of basic magnesium sulfate exceeds 50, the production itself is difficult.
塩基性硫酸マグネシウムは、水酸化マグネシウムと硫酸とを原料として生成することができる。具体的には、硫酸マグネシウム水溶液に水酸化マグネシウム又は酸化マグネシウムを分散させて水熱反応させる方法、可溶性硫酸塩含有水溶液に酸化マグネシウム粉末を分散させた分散液を加熱反応させて繭状物を生成させ、これを強い剪断力で解砕する方法、塩基性硫酸マグネシウムの種粒子と水酸化マグネシウム粒子とを分散させた分散液を硫酸マグネシウム水溶液に混合して加熱することで塩基性硫酸マグネシウムを種粒子の表面に析出させる方法などを挙げることができる。 Basic magnesium sulfate can be produced using magnesium hydroxide and sulfuric acid as raw materials. Specifically, a method in which magnesium hydroxide or magnesium oxide is dispersed in an aqueous magnesium sulfate solution and subjected to a hydrothermal reaction, and a dispersion in which magnesium oxide powder is dispersed in an aqueous solution containing a soluble sulfate is heated to produce a soot-like material. The basic magnesium sulfate is mixed with a magnesium sulfate aqueous solution and heated to disperse the dispersion of basic magnesium sulfate seed particles and magnesium hydroxide particles. The method of depositing on the surface of particle | grains etc. can be mentioned.
ホウ素又はホウ素化合物は、助剤として配合される成分である。ホウ素又はホウ素化合物としては、ホウ素のほか、ホウ酸(H3BO3)、ホウ砂(Na2B4O5(OH)4・8H2O)などを挙げることができる。ホウ素又はホウ素化合物は、塩基性硫酸マグネシウムに含まれる酸化マグネシウムに対して、H3BO3換算で0.5〜8.0重量%の割合で含まれるように混合することが好ましい。ホウ素又はホウ素化合物の配合量が0.5重量%を下回ると、熱伝導性フィラーに含まれるホウ酸の量が少なくなるため、焼成後に得られる熱伝導性フィラーが脆くなり上記のような高い平均アスペクト比になりにくい。また、ホウ素又はホウ素化合物の配合量が8.0重量%を上回ると、焼成後に得られる熱伝導性フィラーに含まれる酸化マグネシウムに対するホウ酸の割合が高くなり、ホウ酸が隣り合った熱伝導性フィラーどうしを接着するため、酸化マグネシウムの分散性が悪くなる。 Boron or a boron compound is a component blended as an auxiliary agent. Examples of boron or boron compounds include boric acid (H 3 BO 3 ), borax (Na 2 B 4 O 5 (OH) 4 · 8H 2 O), and the like in addition to boron. Boron or a boron compound is preferably mixed so as to be contained at a ratio of 0.5 to 8.0% by weight in terms of H 3 BO 3 with respect to magnesium oxide contained in basic magnesium sulfate. When the compounding amount of boron or boron compound is less than 0.5% by weight, the amount of boric acid contained in the thermally conductive filler decreases, so that the thermally conductive filler obtained after firing becomes brittle and has a high average as described above. Difficult to get aspect ratio. Moreover, when the compounding quantity of boron or a boron compound exceeds 8.0 weight%, the ratio of the boric acid with respect to the magnesium oxide contained in the heat conductive filler obtained after baking will become high, and the heat conductivity which boric acid adjoined. Since the fillers are bonded to each other, the dispersibility of magnesium oxide is deteriorated.
(2)混合工程
原料の塩基性硫酸マグネシウムと助剤のホウ素又はホウ素化合物とを、公知の方法で混合する工程である。原料と助剤の混合方法としては、乾式混合、湿式混合のいずれでもよいが、ホウ酸を酸化マグネシウムの表面に均一に付着させやすいことから、湿式混合が好ましい。乾式混合では、塩基性硫酸マグネシウム粉末とホウ素又はホウ素化合物の粉末とを袋などに入れて手作業で混合する方法や、公知のミキサーを用いて機械的に混合する方法を挙げることができる。湿式混合では、ホウ素又はホウ素化合物を水などの溶媒に溶解し、これに塩基性硫酸マグネシウム粉末を混合して撹拌し、ろ過・脱水・乾燥する方法を挙げることができる。撹拌時間、撹拌温度などの条件は適宜設定することができるが、例えば撹拌時間は5〜60分間、撹拌温度は10〜40℃の範囲内とすることができる。
(2) Mixing step In this step, the raw material basic magnesium sulfate and the auxiliary boron or boron compound are mixed by a known method. As a method for mixing the raw material and the auxiliary agent, either dry mixing or wet mixing may be used. However, wet mixing is preferable because boric acid is easily adhered to the surface of magnesium oxide. Examples of the dry mixing include a method in which basic magnesium sulfate powder and boron or boron compound powder are put in a bag and mixed manually, and a method in which mechanical mixing is performed using a known mixer. In the wet mixing, there can be mentioned a method in which boron or a boron compound is dissolved in a solvent such as water, and basic magnesium sulfate powder is mixed and stirred, followed by filtration, dehydration and drying. Conditions such as the stirring time and the stirring temperature can be set as appropriate. For example, the stirring time can be 5 to 60 minutes, and the stirring temperature can be in the range of 10 to 40 ° C.
(3)焼成工程
混合工程で得られた混合物を高温で焼成する工程である。焼成は、電気炉、ガス炉などの公知の装置を用いて行うことができる。焼成温度は500〜1300℃の範囲内で適宜設定することができるが、好ましくは600〜1200℃の範囲内であり、より好ましくは700〜1100℃の範囲内である。焼成温度が500℃を下回ると、焼成が不十分で硫酸や水が残りやすくなる。また、焼成温度が1300℃を上回ると、平均アスペクト比の高い結晶が得られにくい。
(3) Firing step In this step, the mixture obtained in the mixing step is fired at a high temperature. Firing can be performed using a known apparatus such as an electric furnace or a gas furnace. Although a calcination temperature can be suitably set within the range of 500-1300 degreeC, Preferably it is in the range of 600-1200 degreeC, More preferably, it exists in the range of 700-1100 degreeC. If the firing temperature is below 500 ° C., the firing is insufficient and sulfuric acid and water tend to remain. On the other hand, if the firing temperature exceeds 1300 ° C., it is difficult to obtain a crystal having a high average aspect ratio.
焼成は、昇温速度150〜250℃/時間の範囲内で800℃前後まで昇温する第一昇温ステップと、昇温速度50〜150℃/時間の範囲内で1100℃前後まで昇温する第二昇温ステップと、第二昇温ステップの後に冷却又は自然放冷する降温ステップと、を有することが好ましい。このように昇温・降温することで、平均アスペクト比の高い柱状の熱伝導性フィラーを製造することができる。 Firing is performed in a first temperature raising step in which the temperature is raised to about 800 ° C. within a temperature rising rate of 150 to 250 ° C./hour, and to 1100 ° C. in a temperature rising rate of 50 to 150 ° C./hour. It is preferable to have a second temperature raising step and a temperature lowering step that cools or naturally cools after the second temperature raising step. By raising and lowering the temperature in this way, a columnar thermally conductive filler with a high average aspect ratio can be produced.
上記の焼成により、塩基性硫酸マグネシウムからは酸化マグネシウムが、ホウ素又はホウ素化合物からはホウ酸が生成する。また、ウィスカー状の塩基性硫酸マグネシウムから硫酸根や水が抜けて表面に凹凸が、内部に空洞が形成される。ホウ酸は、酸化マグネシウムの表面の凹凸に付着して表面層を形成したり、内部の空洞壁に付着して空洞を充填したりすることで、柱状の酸化マグネシウムを補強する機能を有する。このため、焼成の際に柱状の酸化マグネシウムが脆く砕けにくくなり、平均アスペクト比の高い熱伝導性フィラーを得ることができる。さらに、柱状酸化マグネシウムの表面をホウ酸がコーティングすることで、耐水性を高めている。また、ホウ酸は、例えば酸化ケイ素(SiO2)のような他の酸化物と比べて融剤(助剤)として作用し、柱状(針状)の酸化マグネシウムが形成されやすく好適である。 By the above firing, magnesium oxide is produced from basic magnesium sulfate, and boric acid is produced from boron or a boron compound. In addition, sulfate radicals and water are removed from the whisker-like basic magnesium sulfate, and irregularities are formed on the surface, and cavities are formed inside. Boric acid has a function to reinforce columnar magnesium oxide by adhering to irregularities on the surface of magnesium oxide to form a surface layer, or adhering to an internal cavity wall to fill the cavity. For this reason, the columnar magnesium oxide is brittle and difficult to break during firing, and a heat conductive filler having a high average aspect ratio can be obtained. Furthermore, water resistance is enhanced by coating boric acid on the surface of columnar magnesium oxide. In addition, boric acid is suitable as a flux (auxiliary agent) as compared with other oxides such as silicon oxide (SiO 2 ), and columnar (needle-like) magnesium oxide is easily formed.
<熱伝導性樹脂組成物>
上記の熱伝導性フィラーは、樹脂に配合して樹脂組成物の熱伝導性を高めることができる。以下、本発明の熱伝導性樹脂組成物(以下、単に「熱伝導性樹脂組成物」という)について説明する。
<Thermal conductive resin composition>
Said heat conductive filler can be mix | blended with resin and can improve the heat conductivity of a resin composition. Hereinafter, the heat conductive resin composition of the present invention (hereinafter, simply referred to as “heat conductive resin composition”) will be described.
熱伝導性樹脂組成物に配合される樹脂の種類としては、用途などに応じて適宜設定することができるが、例えば、オレフィン樹脂やアクリル系樹脂などの熱可塑性樹脂でもよく、エポキシ樹脂やフェノール樹脂などの熱硬化性樹脂でもよい。各成分の配合量は、熱伝導性フィラーが酸化マグネシウム換算で1〜60体積%、樹脂が40〜99体積%である。熱伝導性フィラーの配合量が1体積%を下回ると、得られる樹脂組成物の熱伝導率が低くなりやすく、60体積%を上回ると熱伝導性フィラーの割合が高くなるため製造コストが上がるほか、樹脂特性に悪影響を及ぼしやすくなる。 The type of the resin blended in the heat conductive resin composition can be appropriately set according to the use, etc., but may be a thermoplastic resin such as an olefin resin or an acrylic resin, such as an epoxy resin or a phenol resin. A thermosetting resin such as The compounding amount of each component is 1 to 60% by volume of the thermally conductive filler in terms of magnesium oxide and 40 to 99% by volume of the resin. If the blending amount of the thermally conductive filler is less than 1% by volume, the thermal conductivity of the resulting resin composition tends to be low, and if it exceeds 60% by volume, the proportion of the thermally conductive filler increases, resulting in an increase in manufacturing cost. It tends to adversely affect the resin properties.
熱伝導性樹脂組成物は、樹脂と熱伝導性フィラーを公知の方法で混合することで製造することができる。また、得られた熱伝導性樹脂組成物は、押出成形など公知の方法で成形し、所望の形状に加工することができる。 A heat conductive resin composition can be manufactured by mixing resin and a heat conductive filler by a well-known method. Moreover, the obtained heat conductive resin composition can be shape | molded by well-known methods, such as extrusion molding, and can be processed into a desired shape.
熱伝導性樹脂組成物は、各種物品に適用することができるが、特に高い熱伝導率が求められる物品に対して好適に使用することができる。このような物品としては、例えば自動車分野では排ガスバルブ、ランプソケット、各種電装部品を挙げることができる。また、電子機器分野では、ヒートシンク、ダイパッド、プリント配線基板、半導体パッケージ用部品、冷却ファン用部品、ピックアップ部品、コネクタ、スイッチ、軸受け、ケースハウジングなどを挙げることができる。 Although a heat conductive resin composition can be applied to various articles | goods, it can be used conveniently with respect to the articles | goods by which especially high heat conductivity is calculated | required. Examples of such articles include exhaust gas bulbs, lamp sockets, and various electrical components in the automobile field. In the field of electronic equipment, heat sinks, die pads, printed wiring boards, semiconductor package parts, cooling fan parts, pickup parts, connectors, switches, bearings, case housings, and the like can be given.
以下、本発明を実施例に基づいて具体的に説明するが、これらは本発明の目的を限定するものではない。 EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, these do not limit the objective of this invention.
1.湿式混合による熱伝導性フィラーの作製(実施例1、比較例1)
(1)使用原料及び助剤
(a)原料:塩基性針状硫酸マグネシウム(MgSO4・5Mg(OH)2・3H2O)・・・宇部マテリアルズ(株)モスハイジ(平均繊維長15μm、平均繊維径1μm、平均アスペクト比15)
(b)助剤:ホウ酸(H3BO3)・・・シグマアルドリッチジャパン(株)試薬特級
1. Preparation of thermally conductive filler by wet mixing (Example 1, Comparative Example 1)
(1) Raw materials and auxiliaries (a) Raw materials: Basic acicular magnesium sulfate (MgSO 4 · 5Mg (OH) 2 · 3H 2 O) ··· Ube Materials Co., Ltd. Mosheidi (average fiber length 15 µm, average Fiber diameter 1μm, average aspect ratio 15)
(B) Auxiliary agent: boric acid (H 3 BO 3 ) ... Sigma Aldrich Japan Co., Ltd. reagent special grade
(2)混合工程(湿式混合)
ビーカーに純水500mLを入れ、助剤のホウ酸を表1の添加量で添加して溶解した。なお、助剤の添加量は、酸化マグネシウム(MgO)換算で計算した。次に、溶解後の溶液に原料の塩基性硫酸マグネシウムを30g入れ、マグネットスターラ―を使用して室温で30分攪拌した。最後に、真空濾過機を用いて溶液をろ過・脱水して粉末とし、乾燥機を使用して120℃、12時間で粉末を乾燥して混合物を得た。
(2) Mixing process (wet mixing)
In a beaker, 500 mL of pure water was added, and auxiliary boric acid was added at the addition amount shown in Table 1 and dissolved. The amount of auxiliary added was calculated in terms of magnesium oxide (MgO). Next, 30 g of raw basic magnesium sulfate was added to the solution after dissolution, and the mixture was stirred at room temperature for 30 minutes using a magnetic stirrer. Finally, the solution was filtered and dehydrated using a vacuum filter to obtain powder, and the powder was dried at 120 ° C. for 12 hours using a dryer to obtain a mixture.
(3)焼成工程
混合工程で得られた混合物20gを箱型電気炉(中外プロックス製 N100/H)に入れ、焼成を行った。焼成パターンは、室温スタートの後、昇温速度200℃/時間で800℃まで昇温し、続いて昇温速度100℃/時間で1100℃まで昇温した。この温度で1時間保持し、自然放冷して室温まで降温して熱伝導性フィラー(実施例1−1〜1−5)を得た。また助剤のホウ酸を添加せずに上記工程と同様の工程を実施し比較例の酸化マグネシウムを生成した(比較例1)。
(3) Firing step 20 g of the mixture obtained in the mixing step was placed in a box-type electric furnace (N100 / H manufactured by Chugai Prox) and baked. The firing pattern was heated to 800 ° C. at a temperature rising rate of 200 ° C./hour after starting at room temperature, and then heated to 1100 ° C. at a temperature rising rate of 100 ° C./hour. It hold | maintained at this temperature for 1 hour, it stood to cool naturally, and it cooled to room temperature, and obtained the heat conductive filler (Example 1-1 to 1-5). Moreover, the process similar to the said process was implemented, without adding the auxiliary boric acid, and the magnesium oxide of the comparative example was produced | generated (comparative example 1).
(4)物性の測定
得られた熱伝導性フィラー(実施例1−1〜1−5、比較例1)のそれぞれについて、成分組成、BET比表面積、平均短径、平均長径、平均アスペクト比を測定した。測定方法は以下のとおりである。得られた物性値を表1に示した。また、ホウ酸添加量0重量%(比較例1)、0.5重量%(実施例1−1)、2.0重量%(実施例1−3)、4.0重量%(実施例1−4)、8.0重量%(実施例1−5)で得られた熱伝導性フィラーのSEM写真を図1に示した。
(a)フィラー組成(成分組成):酸化マグネシウムはEDTA滴定法、その他組成はICP法を用いて分析した。
(b)BET比表面積:一点法で測定した。
(c)平均短径:画像解析ソフト(Mac-view:(株)マウントテック製)を使って短径を測定し、複数の粒子数の測定結果の平均値を求めた。
(d)平均長径:画像解析ソフト(Mac-view:(株)マウントテック製)を使って長径を測定し、複数の粒子数の測定結果の平均値を求めた。
(e)平均アスペクト比:画像解析ソフト(Mac-view:(株)マウントテック製)を使って柱状酸化マグネシウム各粒子の長径/短径の平均値を求めた。
(4) Measurement of physical properties For each of the obtained thermally conductive fillers (Examples 1-1 to 1-5, Comparative Example 1), the component composition, the BET specific surface area, the average minor axis, the average major axis, and the average aspect ratio are determined. It was measured. The measurement method is as follows. The obtained physical property values are shown in Table 1. Further, the addition amount of
(A) Filler composition (component composition): Magnesium oxide was analyzed using the EDTA titration method, and other compositions were analyzed using the ICP method.
(B) BET specific surface area: measured by a one-point method.
(C) Average short diameter: The short diameter was measured using image analysis software (Mac-view: manufactured by Mounttec Co., Ltd.), and the average value of the measurement results of the number of particles was obtained.
(D) Average major axis: The major axis was measured using image analysis software (Mac-view: manufactured by Mounttec Co., Ltd.), and the average value of the measurement results of the number of particles was obtained.
(E) Average aspect ratio: The average value of major axis / minor axis of each columnar magnesium oxide particle was determined using image analysis software (Mac-view: manufactured by Mounttec Co., Ltd.).
以上の結果から、ホウ酸添加量が0.5〜8.0重量%の実施例は、得られる熱伝導性フィラーのホウ素含有量が0.1〜1.0重量%の範囲内となり、平均長径が1.0μm以上、平均アスペクト比が3を超えることがわかった。また、ホウ酸添加量が0.5重量%(実施例1−1)ではBET比表面積が3.0m2/gを超えており、平均アスペクト比も約3.1と比較的低い値であったが、ホウ酸添加量が1.0重量%以上(実施例1−2〜1−5)ではBET比表面積が2.4〜2.7m2/gとおおむね一定に推移しており、平均アスペクト比は4.0以上となっている。さらに、SEM写真からも、ホウ酸添加量が1.0重量%以上では、アスクペクト比の高い熱伝導性フィラーが多く含まれていることがわかった。このことから、これらの実施例の中でも、ホウ酸添加量は1.0重量%以上(実施例1−2〜1−5)がより好ましく、2.0重量%以上(実施例1−3〜1−5)が特に好ましいことがわかった。 From the above results, examples in which the amount of boric acid added is 0.5 to 8.0% by weight have a boron content of 0.1 to 1.0% by weight in the obtained heat conductive filler, and the average It was found that the major axis was 1.0 μm or more and the average aspect ratio exceeded 3. When the amount of boric acid added was 0.5% by weight (Example 1-1), the BET specific surface area exceeded 3.0 m 2 / g, and the average aspect ratio was about 3.1, which was a relatively low value. However, when the amount of boric acid added was 1.0% by weight or more (Examples 1-2 to 1-5), the BET specific surface area was approximately constant at 2.4 to 2.7 m 2 / g, and the average The aspect ratio is 4.0 or more. Furthermore, from SEM photographs, it was found that when the amount of boric acid added was 1.0% by weight or more, a large amount of thermally conductive filler with a high aspect ratio was contained. Therefore, among these examples, the boric acid addition amount is more preferably 1.0% by weight or more (Examples 1-2 to 1-5), and 2.0% by weight or more (Examples 1-3 to 3). 1-5) has been found to be particularly preferred.
(5)耐吸湿性の評価
ホウ酸添加量2重量%(実施例1−3)と未添加(比較例1)について、耐吸湿性の評価を行った。評価方法は、まず、熱伝導性フィラーのサンプル3gを磁性皿に入れ、温度60℃、湿度90%の恒温恒湿槽にサンプル入りの磁性皿を入れて48時間保持した。恒温恒湿槽から磁性皿を取り出し、サンプルの重量増加率を測定した。重量増加率=(保持後の重量増加分(g)/最初のサンプル量(3g))×100(%)で計算した。
(5) Evaluation of hygroscopic resistance The hygroscopic resistance of the boric acid addition amount 2% by weight (Example 1-3) and non-added (Comparative Example 1) was evaluated. The evaluation method was as follows. First, 3 g of the thermally conductive filler sample was placed in a magnetic dish, and the sampled magnetic dish was placed in a constant temperature and humidity chamber at a temperature of 60 ° C. and a humidity of 90% and held for 48 hours. The magnetic dish was taken out from the constant temperature and humidity chamber, and the weight increase rate of the sample was measured. Weight increase rate = (weight increase after holding (g) / initial sample amount (3 g)) × 100 (%).
その結果、比較例1のサンプルでは重量増加率が2.41%だったのに対して、実施例1−3のサンプルでは重量増加率が0.52%と大幅に減少した。このことから、ホウ酸を含む熱伝導性フィラーは、耐吸湿性が高くなることがわかった。 As a result, the weight increase rate of the sample of Comparative Example 1 was 2.41%, whereas the weight increase rate of the sample of Example 1-3 was significantly reduced to 0.52%. From this, it was found that the heat conductive filler containing boric acid has high moisture absorption resistance.
2.乾式混合による熱伝導性フィラーの作製(実施例2)
上記の「1.湿式混合による熱伝導性フィラーの作製(実施例1)」の混合工程において、原料と助剤の混合を、袋に原料の粉末と助剤の粉末とを添加し、袋を振って混合を実施した以外は実施例1と同じ条件で熱伝導性フィラーを作製した。ホウ酸添加量0.5重量%(実施例2−1)、2.0重量%(実施例2−2)で得られた熱伝導性フィラーのSEM写真を図2に示した。なお、この図には、比較のため実施例1の湿式混合で得られたSEM写真も示している。
2. Preparation of thermally conductive filler by dry mixing (Example 2)
In the mixing step of “1. Preparation of thermally conductive filler by wet mixing (Example 1)”, mixing of raw material and auxiliary agent, adding raw material powder and auxiliary agent powder to the bag, A thermally conductive filler was produced under the same conditions as in Example 1 except that the mixing was performed by shaking. The SEM photograph of the heat conductive filler obtained by boric acid addition amount 0.5 weight% (Example 2-1) and 2.0 weight% (Example 2-2) was shown in FIG. In addition, in this figure, the SEM photograph obtained by the wet mixing of Example 1 is also shown for the comparison.
この結果から、乾式混合(実施例2)と湿式混合(実施例1)のいずれにおいても柱状の熱伝導性フィラーが得られることがわかった。また、乾式混合と湿式混合を比較すると、湿式混合のほうが乾式混合よりも柱状に長くなっている熱伝導性フィラーの数が多い傾向にある。したがって、平均アスペクト比の高い熱伝導性フィラーを得るという観点からは、湿式混合のほうが乾式混合よりも好ましいと考えられる。 From this result, it was found that a columnar thermally conductive filler was obtained in both dry mixing (Example 2) and wet mixing (Example 1). Moreover, when dry mixing and wet mixing are compared, there is a tendency that wet mixing has a larger number of thermally conductive fillers that are longer in a columnar shape than dry mixing. Therefore, from the viewpoint of obtaining a heat conductive filler having a high average aspect ratio, it is considered that wet mixing is preferable to dry mixing.
3.ホウ砂を助剤とした熱伝導性フィラーの作製(実施例3)
上記の「1.湿式混合による熱伝導性フィラーの作製(実施例1)」の助剤としてホウ砂(Na2B4O5(OH)4・8H2O)(片山化学工業(株)試薬特級)を用い、添加量を3.06重量%とした以外は実施例1と同じ条件で熱伝導性フィラーを作製した。得られた熱伝導性フィラーは、平均短径0.65μm、平均長径2.65μmで平均アスペクト比が4.2であった。熱伝導性フィラーのSEM写真を図3に示した。なお、この図には、比較のため、ホウ酸2.0重量%を添加して湿式混合で製造した実施例1−3のSEM写真も示している。
3. Preparation of thermally conductive filler using borax as auxiliary agent (Example 3)
Borax (Na 2 B 4 O 5 (OH) 4 · 8H 2 O) (Katayama Chemical Co., Ltd. Reagent) as an aid for the above-mentioned “1. Preparation of thermally conductive filler by wet mixing (Example 1)” A heat conductive filler was prepared under the same conditions as in Example 1 except that the amount added was 3.06 wt%. The obtained heat conductive filler had an average minor axis of 0.65 μm, an average major axis of 2.65 μm, and an average aspect ratio of 4.2. An SEM photograph of the thermally conductive filler is shown in FIG. In addition, this figure also shows the SEM photograph of Example 1-3 which added 2.0 weight% of boric acid and manufactured by wet mixing for the comparison.
この結果から、ホウ酸に替えてホウ砂を用いても柱状の熱伝導性フィラーを作製することができることがわかった。 From this result, it was found that a columnar thermally conductive filler can be produced even if borax is used instead of boric acid.
4.樹脂組成物の作製(実施例4)
(1)混練に使用した物質
(a−1)熱伝導性フィラー(実施例4):実施例1−3(ホウ酸:MgO換算で2.0重量%添加品)
(a−2)粒状フィラー(比較例2):宇部マテリアルズ(株)製酸化マグネシウム (平均粒径10μm、平均アスペクト比1.4)
(b)樹脂:エチレンエチルアクリレート(EEA)(日本ユニカー(株)DPDJ-6169BKC)
4). Production of Resin Composition (Example 4)
(1) Substance used for kneading (a-1) Thermally conductive filler (Example 4): Example 1-3 (Boric acid: 2.0% by weight additive in terms of MgO)
(A-2) Granular filler (Comparative example 2): Magnesium oxide manufactured by Ube Materials Co., Ltd. (
(B) Resin: Ethylene ethyl acrylate (EEA) (Japan Unicar Corporation DPDJ-6169BKC)
(2)樹脂とフィラーの混練
熱伝導性フィラー(実施例4)と粒状フィラー(比較例1)のそれぞれについて、EEA樹脂:フィラー=50体積%:50体積%とEEA樹脂:フィラー=75体積%:25体積%(実施例4−2)の2つの配合比で樹脂と混練した。混練は、混練装置(東洋精機 LABO PLASTMILL 10D100−01)を用い、160℃、10分間を行った。混練物を180℃でヒートプレスして120mm×120mm×3mmTの試験片を作製した。
(2) Kneading of resin and filler For each of the thermally conductive filler (Example 4) and the granular filler (Comparative Example 1), EEA resin: filler = 50 vol%: 50 vol% and EEA resin: filler = 75 vol% : Kneaded with resin at two blending ratios of 25% by volume (Example 4-2). The kneading was performed at 160 ° C. for 10 minutes using a kneading apparatus (Toyo Seiki LABO PLASTMILL 10D100-01). The kneaded product was heat-pressed at 180 ° C. to prepare a test piece of 120 mm × 120 mm × 3 mmT.
(3)熱伝導率評価
評価装置として、非定常法細線加熱法(京都電子(株) QTM−500)を使用した。装置メーカーの標準サンプルの石英基板の上に試験片を乗せ、試験片の熱伝導率を測定した。その結果を図4に示す。
(3) Thermal conductivity evaluation An unsteady thin wire heating method (Kyoto Electronics Co., Ltd. QTM-500) was used as an evaluation device. A test piece was placed on a quartz substrate as a standard sample of an apparatus manufacturer, and the thermal conductivity of the test piece was measured. The result is shown in FIG.
この結果から、柱状の熱伝導性フィラー(実施例4)は、粒状のフィラー(比較例2)と比べて、樹脂組成物の熱伝導率が向上していることがわかった。具体的には、熱伝導性フィラーの配合量が50体積%では約1.6W/m・Kの非常に高い熱伝導率とすることができ、20体積%であっても1.0W/m・K以上と比較的高い熱伝導率とすることができた。また、柱状の熱伝導性フィラーは、粒状のフィラーの約半分の添加量で同等の熱伝導率を示すことがわかった。このことから、平均アスペクト比の高い熱伝導性フィラーを使用することで、樹脂組成物の熱伝導率を向上させ、樹脂組成物の軽量化を図ることができることがわかった。 From this result, it was found that the thermal conductivity of the resin composition was improved in the columnar thermally conductive filler (Example 4) compared to the granular filler (Comparative Example 2). Specifically, when the blending amount of the heat conductive filler is 50% by volume, a very high heat conductivity of about 1.6 W / m · K can be obtained, and even when it is 20% by volume, 1.0 W / m.・ It was possible to achieve a relatively high thermal conductivity of K or more. Moreover, it turned out that a columnar heat conductive filler shows an equivalent heat conductivity with the addition amount of about half of a granular filler. From this, it was found that by using a heat conductive filler having a high average aspect ratio, the heat conductivity of the resin composition can be improved and the weight of the resin composition can be reduced.
Claims (7)
長径/短径で定義されるアスペクト比の平均値が2以上であることを特徴とする熱伝導性フィラー。 Containing at least columnar magnesium oxide and boron;
An average value of aspect ratio defined by major axis / minor axis is 2 or more.
ウィスカー状の塩基性硫酸マグネシウムとホウ素又はホウ素化合物とを混合する混合工程と、
前記混合後の混合物を500〜1300℃で焼成する焼成工程と、
を含むことを特徴とする熱伝導性フィラーの製造方法。 It is a manufacturing method of the heat conductive filler in any one of Claims 1-4,
A mixing step of mixing whisker-like basic magnesium sulfate with boron or a boron compound;
A firing step of firing the mixture after mixing at 500 to 1300 ° C .;
The manufacturing method of the heat conductive filler characterized by including.
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CN115667147A (en) * | 2020-12-25 | 2023-01-31 | 宇部材料工业株式会社 | Magnesium oxide powder, thermally conductive filler, resin composition, and method for producing magnesium oxide powder |
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