JP3572692B2 - α-Alumina powder-containing resin composition and rubber composition - Google Patents
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Description
【０００１】
【産業上の利用分野】
本発明は、α−アルミナ粉末を含有する樹脂組成物またはゴム組成物、特に高熱伝導性で成形性に優れたα−アルミナ粉末を含有する樹脂組成物またはゴム組成物に関する。
【０００２】
【従来の技術】
近年、電子材料の分野を中心に機器の集積化、高密度化、コンパクト化が進み、それに伴い半導体等の電子部品から発散される熱の放散が大きな課題となっている。そのため、高い熱伝導性と高い電気絶縁性を有する樹脂組成物あるいはゴム組成物が要求されるようになり、熱伝導性封止材、熱伝導性接着材、放熱シートとして実用化されている。
【０００３】
これらの材料には、高い熱伝導性、電気絶縁性の他に、低い熱膨張率であること、耐熱性が高いことと、特に材料特性を十分に引き出すため成形加工性に優れることが要求されている。これらの材料として用いられる熱伝導性電気絶縁樹脂組成物あるいはゴム組成物には、エポキシ樹脂、イミド樹脂、シリコーン樹脂、シリコーンゴム等に、シリカ、アルミナ、マグネシア、ボロンナイトライド等の無機粉末を添加したものが知られている。
【０００４】
上記無機粉末として、電融アルミナや焼結アルミナを粉砕したα−アルミナが用いることが報告されているが、該α−アルミナは、破砕形状で鋭いカッテイングエッジ（破面）を有するため、充填性に劣り、高い熱伝導性が期待される場合には、十分なものではなかった。
【０００５】
上記の問題を解決するため、特開昭６４−６９６６１号公報には、アルミナ粒子とカッテイングエッジを有しない形状である球状コランダム粒子からなるアルミナを充填した高熱伝導性ゴム・プラスチック組成物が提案されている。しかし、該球状コランダム粒子は、電融アルミナ、焼結アルミナの粉砕品の、粒度分布を維持しつつ、カッテイングエッジを減少させ、同時に形状を球状化させる処理をすることにより得たものであり、粒度分布が広く、十分に高い熱伝導性と優れた成形加工性を同時に満足させる組成物を得るためのものとしては、必ずしも満足できるものではなかった。
【０００６】
一方、特公昭５８−２２０５５号公報には、特殊なα−アルミナ粉末、すなわち形状因子が１．０〜１．４で、かつある一定の粒度分布を有するα−アルミナ粉末は、シリコーンゴムに高充填することが可能であり、得られたシリコーンゴムは高い熱伝導性を有することが記載されている。しかし、該α−アルミナ粉末は一部が凝集した球状粒子であり、これをさらにロッドミルあるいはマラー及びらいかい器形式の粉体処理装置で解砕する必要があり、この解砕により微粒子が発生するとともに、カッテイングエッジが生じることは避けられない。このため、高い熱伝導性と優れた成形加工性を同時に満足させる樹脂またはゴム組成物は得られていない。
【０００７】
また、特開平４−３２８１６３号公報には、オルガノポリシロキサンに球状アルミナと硬化剤を添加した熱伝導性シリコーンゴム組成物が記載されている。ここで用いられている球状アルミナは、金属アルミニウムを溶融してから酸素と直接酸化させることにより得られ、高い真球度を有する。しかし、該球状アルミナは球状化させた溶融アルミニウムを酸化させるため、得られる球状アルミナの粒度分布が広い。したがって高レベルの性能を期待する用途には、必ずしも満足できるものではない。また、溶融アルミニウムは均一には酸化されず、活性が高い表面を有するため、貯蔵安定性も必ずしも十分満足できるものではない。
【０００８】
【発明が解決しようとする課題】
本発明の目的は、上記した問題点を解決して、高い熱伝導性と優れた成形加工性の両方を満足させることのできるα−アルミナ粉末を含有する樹脂またはゴム組成物を提供することにある。
【０００９】
【課題を解決するための手段】
本発明はつぎの発明からなる。
〔Ｉ〕（１）Ａ１成分：実質的に破面を有しない、多面体一次粒子よりなり、重量累積粒度分布の微粒側から累積１０％、累積５０％の粒径をそれぞれＤ１０、Ｄ５０としたとき、Ｄ５０が５０μｍ以下で、Ｄ５０／Ｄ１０比が２以下であるα−アルミナ粉末、（２）Ｂ成分：樹脂またはゴム、を含み、該Ａ１成分の配合量が１５〜７０体積％であることを特徴とするα−アルミナ粉末含有樹脂組成物またはゴム組成物。
【００１０】
〔ＩＩ〕（１）Ａ１成分：実質的に破面を有しない、多面体一次粒子よりなり、重量累積粒度分布の微粒側から累積１０％、累積５０％の粒径をそれぞれＤ１０、Ｄ５０としたとき、Ｄ５０が５０μｍ以下で、Ｄ５０／Ｄ１０比が２以下であるα−アルミナ粉末、（２）Ａ２成分：前記Ａ１成分のＤ５０と該Ａ２成分のＤ５０の比が５以上であるα−アルミナ粉末、及び（３）Ｂ成分：樹脂またはゴム、を含み、総α−アルミナ配合量（Ａ１成分とＡ２成分の配合量の合計）が１５〜９４体積％であり、該総α−アルミナ配合量中のＡ１成分の割合が４０重量％以上、１００重量％未満であることを特徴とするα−アルミナ粉末含有樹脂組成物またはゴム組成物。
【００１１】
以下に本発明について詳しく説明する。本発明に用いることのできる、Ａ１成分のα−アルミナ粉末は、実質的に破面を有しない、多面体一次粒子よりなり、重量累積粒度分布の微粒側から累積１０％、累積５０％の粒径をそれぞれＤ１０、Ｄ５０としたとき、Ｄ５０が５０μｍ以下で、Ｄ５０／Ｄ１０比が２以下であるα−アルミナ粉末である。該α−アルミナ粉末を樹脂またはゴムに配合することにより、成形加工性を損なうことなく高充填できるとともに、該α−アルミナ粒子が多面体形状を有しているため、粒子間の接触が球形粒子のように点ではなく、面接触し、熱伝導性を高めることが可能になる。該α−アルミナ粉末の配合量は、１５〜７０体積％、好ましくは５０〜７０体積％、さらに好ましくは６０〜７０体積％である。１５体積％未満では熱伝導率を高める効果が低く、また、７０体積％を越えると成形加工性が低下する。
【００１２】
さらに、Ａ１成分のα−アルミナ粉末に、該Ａ１成分のＤ５０に対するＤ５０の比が５以上である、より微細な粒子径を有するα−アルミナ粉末（Ａ２成分）を混合して、樹脂またはゴムに充填することにより、成形加工性を損なうことなく、さらに高充填することが可能になる。この場合、総α−アルミナ配合量（Ａ１成分とＡ２成分の配合量の合計）中のＡ１成分の割合が４０重量％以上、１００重量％未満、好ましくは５０重量％以上９０重量％以下、さらに好ましくは６５重量％以上８５重量％以下である。総α−アルミナ配合量は、１５〜９４体積％、好ましくは５０〜９４体積％、さらに好ましくは７０〜９４体積％である。微粒子のα−アルミナ粉末（Ａ２成分）の配合量が総アルミナ粉末配合量の６０重量％を越えると成形加工性を低下させるので好ましくない。
【００１３】
上記本発明において、Ａ１成分のα−アルミナ粉末として、Ｄ５０／Ｄ１０比が１．５以下の、実質的に破面を有しない、多面体一次粒子よりなるα−アルミナ粉末を用いることが好ましい。
【００１４】
また、Ａ１成分のα−アルミナ粉末は、重量累積粒度分布の微粒側から累積９０％の粒径をＤ９０としたとき、Ｄ９０／Ｄ１０比が３以下の、実質的に破面を有しない、多面体一次粒子よりなるα−アルミナ粉末であることが好ましい。
【００１５】
さらに、Ａ１成分のα−アルミナ粉末は、Ｄ５０をＢＥＴ比表面積径で除した値が１．５以下の、実質的に破面を有しない、多面体一次粒子よりなるα−アルミナ粉末であることが好ましい。この本発明に好ましく用いられるα−アルミナ粉末は、粒子表面に欠陥が殆ど無いため、吸着水分が低く、エポキシ樹脂やイミド樹脂に充填した場合、水分に起因するクラックの発生を低減でき、また、シリコーン樹脂やシリコーンゴムに充填した場合、シリコーン中のケイ素に結合した水素との反応が抑制され優れた貯蔵安定性を有することが可能になる。
【００１６】
該Ａ１成分のα−アルミナ粉末としては、例えば、原料としての遷移アルミナまたは熱処理により遷移アルミナとなるアルミナ前駆体を、塩化水素ガスを含有する雰囲気ガス中にて焼成することにより得られるα−アルミナ粉末（特開平６−１９１８３３号公報あるいは特開平６−１９１８３６号公報）を挙げることができる。
【００１７】
本発明に用いるＡ２成分のα−アルミナ粉末としては、バイヤー法アルミナ、電融アルミナ、有機金属の加水分解法によるアルミナ等、工業的規模で入手可能な各種のアルミナ粉末を使用することができる。
【００１８】
本発明に用いる樹脂成分またはゴム成分としては、熱伝導性が高い樹脂やゴムが好適であり、例えば、エポキシ樹脂、イミド樹脂、ポリエステル樹脂、シリコーン樹脂、シリコーンゴム等を挙げることができる。また、これらの樹脂類やゴム類を混合して用いることもできる。
エポキシ樹脂としては、ビスフェノールＡ型、フェノールノボラック、クレゾールノボラック等のポリフェノール化合物のグリシジルエーテル化物に代表される物質を使用することができる。
【００１９】
シリコーンゴムの主成分としては、直鎖状オルガノポリシロキサンで加硫可能なものであれば特に制限されず、例えばジメチルポリシロキサンまたはビニル基含有ジメチルポリシロキサンと有機過酸化物からなる熱加硫型オルガノポリシロキサン、ビニル基含有ジメチルポリシロキサンと−ＳｉＨ基を有するジメチルハイドロジエンポリシロキサンと触媒としての白金または白金化合物からなる付加反応加硫型オルガノポリシロキサン、またはこれらの混合物が好ましく用いられる。
【００２０】
なお、本発明の樹脂組成物またはゴム組成物中には、α−アルミナ粉末以外の無機粉末、分散剤、脱泡剤、離型剤、難燃剤、着色剤等の各種添加剤を、本発明の目的を損なわない範囲にて、添加することも可能である。
【００２１】
本発明において、α−アルミナ粉末を樹脂あるいはゴムに混合する方法は特に制限されず、ロール、ニーダーあるいはプラネタリー型撹拌機等の一般の混合機を用いて混合、コンパウンド化することが可能である。
【００２２】
本発明の樹脂組成物またはゴム組成物を用いて半導体等、電子部品を封止する方法としては、トランスファーモールド、コンプレッションモールド、インジェクションモールド、あるいはポッテイング法等を用いることができ、成形する方法としては、押出成形、射出成形、圧縮成形、カレンダーロール成形等を用いることができる。
【００２３】
【実施例】
次に実施例により本発明をさらに詳しく説明するが、本発明はこれらの実施例に限定されるものではない。
【００２４】
なお、本発明における各種の測定は次のようにして行った。
１． 一次粒子径の測定
ＳＥＭ（走査型電子顕微鏡、日本電子（株）製：Ｔ−３００）を使用して粉末粒子の写真を撮影し、その写真から５ないし１０個の粒子を選び出して画像解析を行い、その平均値として求めた。
【００２５】
２． 粒度分布の測定
セデイグラフ５０００ＥＴ（マイクロメリテイクス社製）を使用し、Ｘ線透過沈降法により測定した。
【００２６】
３． ＢＥＴ比表面積の測定
フローソーブＩＩ ２３００型（マイクロメリテイクス社製）を使用して測定した。
【００２７】
実施例１
住友化学工業（株）製のγ−アルミナ粉末（商品名：ＡＫＰ−Ｇ１５）を塩化水素ガス１００％雰囲気中、１１００℃で、２時間焼成し、α−アルミナ粉末を得た。得られたα−アルミナ粉末は実質的に破面を有しない、８〜２０面を有する多面体粒子よりなり、一次粒子径は１８μｍであった。粒度分布を測定した結果、Ｄ５０が１８μｍ、Ｄ１０が１４μｍ、Ｄ９０が２５μｍであり、Ｄ５０／Ｄ１０比は１．３、Ｄ９０／Ｄ１０比は１． ８であった。ＢＥＴ比表面積は０． １ｍ２ ／ｇであったので、ＢＥＴ比表面積径は１５μｍとなり、Ｄ５０をＢＥＴ比表面積径で除した値は１． ２であった。
【００２８】
住友化学工業（株）製のγ−アルミナ粉末（商品名：ＡＫＰ−Ｇ１５）にＢＥＴ比表面積が５． ８ｍ２ ／ｇの住友化学工業（株）製α−アルミナ粉末（商品名：ＡＫＰ−３０）を０． ３重量％添加して混合原料とし、該混合原料を塩化水素ガス１００％雰囲気中、１０００℃で、１時間焼成し、α−アルミナ粉末を得た。得られたα−アルミナ粉末は実質的に破面を有しない、８〜２０面を有する多面体粒子よりなり、一次粒子径は２μｍであった。粒度分布を測定した結果、Ｄ５０が２． ０μｍであった。ＢＥＴ比表面積は１． ０ｍ２ ／ｇであった。
【００２９】
上記一次粒子径が１８μｍのα−アルミナ粉末と、上記一次粒子径が２μｍのα−アルミナ粉末を種々の割合で混合し、得られたα−アルミナの混合粉末を２ｇ採取して内径２ｃｍの金型に充填して、１５００ｋｇ／ｃｍ２ の圧力を一軸プレス機によりかけた。金型ごと一軸プレス機から取り外し、加圧後の粉末の密度を重量と寸法から算出した結果を表１に示した。上記一次粒子径が１８μｍのα−アルミナ粉末と上記一次粒子径が２μｍのα−アルミナ粉末の重量比が８０：２０の場合に最も密度が高くなり、３． ０３ｇ／ｃｍ３ となった。
【００３０】
上記一次粒子径が１８μｍのα−アルミナ粉末と上記一次粒子径が２μｍのα−アルミナ粉末を重量比で８０：２０の割合で混合し、α−アルミナ混合粉末を得てエポキシ樹脂に配合した。
エポキシ樹脂として住友化学工業（株）製のエポキシ樹脂（商品名：スミエポキシＥＳＣＮ−１９５−ＸＬ）を使用し、エポキシ硬化剤、硬化促進剤、離型剤およびカップリング剤を添加し、該α−アルミナ混合粉末を７０体積％となるように添加して、１１０℃でロールにより混練を行った。体積％は、α−アルミナの密度を４． ０ｇ／ｃｍ３ 、エポキシ樹脂の密度を１． ２ｇ／ｃｍ３ として重量から計算した。該混合物をトランスファー成形により板状に成形し、１８０℃に加熱して硬化させ、複合体（成形体）を作製した。得られた複合体の室温（２１℃）における熱伝導度をレーザーフラッシュ法により測定した結果、３．０Ｗ／ｍＫであった。
【００３１】
【表１】
実施例２
実施例１で作製した一次粒子径が１８μｍのα−アルミナ粉末と、住友化学工業（株）製のα−アルミナ粉末（商品名：ＡＫＰ−３０）を重量比で８０：２０の割合で混合し、α−アルミナ混合粉末を得た。ＡＫＰ−３０の粒度分布を測定した結果、Ｄ５０が０． ３５μｍであり、一次粒子径が１８μｍのα−アルミナのＤ５０をＡＫＰ−３０のＤ５０で除した値は５１であった。該混合粉末を充填剤として、実施例１と同様にして、ただし添加量は７５体積％となるようにエポキシ樹脂に配合して複合体を作製した。得られた複合体の室温（２１℃）における熱伝導度をレーザーフラッシュ法により測定した結果、５． １Ｗ／ｍＫであった。
【００３３】
実施例３
実施例１で作製した一次粒子径が１８μｍのα−アルミナ粉末と、住友化学工業（株）製のα−アルミナ粉末（商品名：ＡＫＰ−３０）を重量比で８０：２０の割合で混合し、α−アルミナ混合粉末を得た。該混合粉末を充填剤として、実施例１と同様にして、ただし添加量は８０体積％となるようにエポキシ樹脂に添加し複合体を作製した。得られた複合体の室温（２１℃）における熱伝導度をレーザーフラッシュ法により測定した結果、８． ９Ｗ／ｍＫであった。
【００３４】
比較例１
フジミインコーポレーテッド社製の電融アルミナＷＡ＃８００とＷＡ＃６０００を種々の割合で混合して、実施例１と同様にして加圧後の粉末の密度を測定した。測定の結果を表２に示した。ＷＡ＃８００は破面を有する不定形粒子よりなるα−アルミナ粉末であり、Ｄ５０が１５μｍ、Ｄ１０が１１μｍ、Ｄ９０が１７μｍであり、Ｄ５０／Ｄ１０比は１． ４、Ｄ９０／Ｄ１０比は１． ６であった。ＢＥＴ比表面積は０． ２ｍ２ ／ｇであったので、ＢＥＴ比表面積径は７． ５μｍとなり、Ｄ５０をＢＥＴ比表面積径で除した値は２． ０であった。ＷＡ＃６０００は破面を有する不定形粒子よりなるα−アルミナ粉末であり、Ｄ５０が１． ８μｍ、であり、ＷＡ＃８００のＤ５０をＷＡ＃６０００のＤ５０比で除した値は８． ３であった。また、ＷＡ＃６０００のＢＥＴ比表面積は３． ７ｍ２ ／ｇであった。
【００３５】
ＷＡ＃８００とＷＡ＃６０００を重量比で８０：２０の割合で混合し、実施例１と同様にしてエポキシ樹脂に充填剤として添加したが、総アルミナ添加量を７０体積％とした場合はエポキシ樹脂とα−アルミナ粉末の混合物は流動性のある混合物にならず、トランスファー成形ができなかった。総アルミナ添加量を６０体積％として実施例１と同様にして複合体を作製した。得られた複合体の室温（２１℃）における熱伝導度をレーザーフラッシュ法により測定した結果、１．６Ｗ／ｍＫであった。
【００３６】
【表２】
比較例２
実施例１で用いたエポキシ樹脂にα−アルミナ粉末を配合せずに成形し硬化させたものの室温（２１℃）における熱伝導度をレーザーフラッシュ法により測定した結果、０． ２Ｗ／ｍＫであった。
【００３８】
【発明の効果】
本発明のα−アルミナ粉末含有樹脂組成物またはゴム組成物は、高い熱伝導性を有し、成形性に優れた電気絶縁性の材料であり、熱伝導性封止材、熱伝導性接着材、放熱シート等の用途に適している。[0001]
[Industrial applications]
TECHNICAL FIELD The present invention relates to a resin composition or a rubber composition containing α-alumina powder, particularly a resin composition or a rubber composition containing α-alumina powder having high heat conductivity and excellent moldability.
[0002]
[Prior art]
2. Description of the Related Art In recent years, integration, densification, and compactness of devices have been progressing mainly in the field of electronic materials, and accordingly, dissipation of heat radiated from electronic components such as semiconductors has become a major issue. Therefore, a resin composition or a rubber composition having high thermal conductivity and high electrical insulation has been required, and has been practically used as a thermal conductive sealing material, a thermal conductive adhesive, and a heat dissipation sheet.
[0003]
In addition to high thermal conductivity and electrical insulation, these materials are required to have a low coefficient of thermal expansion, high heat resistance, and especially excellent moldability in order to sufficiently bring out the material properties. ing. To the thermally conductive electrical insulating resin composition or rubber composition used as these materials, an inorganic powder such as silica, alumina, magnesia, boron nitride, etc. is added to epoxy resin, imide resin, silicone resin, silicone rubber, etc. Is known.
[0004]
It has been reported that α-alumina obtained by pulverizing fused alumina or sintered alumina is used as the inorganic powder. However, since α-alumina has a sharp cutting edge (fracture surface) in a crushed shape, its filling property is low. However, when high thermal conductivity was expected, it was not sufficient.
[0005]
In order to solve the above-mentioned problems, Japanese Patent Application Laid-Open No. 64-69661 proposes a highly heat-conductive rubber / plastic composition filled with alumina consisting of alumina particles and spherical corundum particles having a shape having no cutting edge. ing. However, the spherical corundum particles are obtained by performing a process of reducing the cutting edge and simultaneously spheroidizing the shape while maintaining the particle size distribution of the crushed product of fused alumina and sintered alumina. It was not always satisfactory for obtaining a composition having a wide particle size distribution and simultaneously satisfying sufficiently high thermal conductivity and excellent moldability.
[0006]
On the other hand, Japanese Patent Publication No. 58-22055 discloses that a special α-alumina powder, that is, an α-alumina powder having a shape factor of 1.0 to 1.4 and having a certain particle size distribution, is highly suitable for silicone rubber. It is described that it can be filled and the resulting silicone rubber has a high thermal conductivity. However, the α-alumina powder is a partly aggregated spherical particle, which needs to be further crushed by a rod mill or a muller and a grinder-type powder processing apparatus, and fine particles are generated by this crushing. At the same time, it is inevitable that a cutting edge occurs. For this reason, a resin or rubber composition that simultaneously satisfies high thermal conductivity and excellent moldability has not been obtained.
[0007]
Japanese Patent Application Laid-Open No. 4-328163 describes a thermally conductive silicone rubber composition obtained by adding spherical alumina and a curing agent to an organopolysiloxane. The spherical alumina used here is obtained by melting metallic aluminum and then directly oxidizing it with oxygen, and has high sphericity. However, since the spherical alumina oxidizes the spheroidized molten aluminum, the obtained spherical alumina has a wide particle size distribution. Therefore, it is not always satisfactory for applications expecting a high level of performance. Moreover, since the molten aluminum is not uniformly oxidized and has a surface with high activity, the storage stability is not always sufficiently satisfactory.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a resin or rubber composition containing α-alumina powder that can solve both the above-mentioned problems and satisfy both high thermal conductivity and excellent moldability. is there.
[0009]
[Means for Solving the Problems]
The present invention comprises the following inventions.
[I] (1) A1 component: consisting of polyhedral primary particles having substantially no fractured surface, where D10 and D50 are the particle diameters of 10% and 50%, respectively, from the fine particle side of the weight cumulative particle size distribution. , D50 is 50 µm or less, D50 / D10 ratio is 2 or less, (2) B component: resin or rubber, and the compounding amount of the A1 component is 15 to 70% by volume. Characteristic α-alumina powder-containing resin composition or rubber composition.
[0010]
[II] (1) A1 component: consisting of polyhedral primary particles having substantially no fractured surface, when the particle diameters of 10% and 50% are D10 and D50, respectively, from the fine particle side of the weight cumulative particle size distribution. Α-alumina powder having a D50 of 50 μm or less and a D50 / D10 ratio of 2 or less, (2) A2 component: an α-alumina powder having a ratio of D50 of the A1 component and D50 of the A2 component of 5 or more, And (3) a B component: a resin or a rubber, wherein the total amount of α-alumina (the total amount of the components A1 and A2) is 15 to 94% by volume, and The α-alumina powder-containing resin composition or the rubber composition, wherein the proportion of the A1 component is 40% by weight or more and less than 100% by weight.
[0011]
Hereinafter, the present invention will be described in detail. The A1 component α-alumina powder that can be used in the present invention is composed of polyhedral primary particles having substantially no fracture surface, and has a particle size of 10% cumulative and 50% cumulative from the fine particle side of the weight cumulative particle size distribution. Is D10 and D50, respectively, and is an α-alumina powder having a D50 of 50 μm or less and a D50 / D10 ratio of 2 or less. By blending the α-alumina powder with a resin or rubber, high filling can be achieved without impairing the moldability, and since the α-alumina particles have a polyhedral shape, contact between the particles is limited to spherical particles. It is possible to improve the thermal conductivity by making surface contact instead of point. The compounding amount of the α-alumina powder is 15 to 70% by volume, preferably 50 to 70% by volume, and more preferably 60 to 70% by volume. If it is less than 15% by volume, the effect of increasing the thermal conductivity is low, and if it exceeds 70% by volume, the moldability decreases.
[0012]
Further, α-alumina powder of component A1 is mixed with α-alumina powder (component A2) having a finer particle diameter, wherein the ratio of D50 to D50 of component A1 is 5 or more, to form a resin or rubber. By filling, even higher filling can be achieved without impairing the moldability. In this case, the proportion of the A1 component in the total amount of α-alumina (the sum of the amounts of the components A1 and A2) is 40% by weight or more and less than 100% by weight, preferably 50% by weight or more and 90% by weight or less. Preferably it is 65% by weight or more and 85% by weight or less. The total amount of α-alumina is 15 to 94% by volume, preferably 50 to 94% by volume, and more preferably 70 to 94% by volume. If the amount of the fine particles of α-alumina powder (component A2) exceeds 60% by weight of the total amount of the alumina powder, the molding processability is undesirably reduced.
[0013]
In the present invention, it is preferable to use an α-alumina powder having a D50 / D10 ratio of 1.5 or less and substantially having no fractured surface and composed of polyhedral primary particles as the α-alumina powder of the component A1.
[0014]
Further, the α-alumina powder of the A1 component has a D90 / D10 ratio of 3 or less and has substantially no fractured surface when the particle size of 90% of the particles is D90 from the fine particle side in the weight cumulative particle size distribution. It is preferably an α-alumina powder composed of primary particles.
[0015]
Further, the α-alumina powder of the A1 component may be an α-alumina powder composed of polyhedral primary particles having substantially no fracture surface and having a value obtained by dividing D50 by a BET specific surface area diameter of 1.5 or less. preferable. The α-alumina powder preferably used in the present invention has almost no defects on the particle surface, and therefore has a low adsorbed moisture, and when filled in an epoxy resin or an imide resin, can reduce the occurrence of cracks due to moisture, When filled in a silicone resin or silicone rubber, the reaction with hydrogen bonded to silicon in silicone is suppressed, and excellent storage stability can be obtained.
[0016]
As the α-alumina powder of the A1 component, for example, α-alumina obtained by calcining a transition alumina as a raw material or an alumina precursor which becomes a transition alumina by heat treatment in an atmosphere gas containing hydrogen chloride gas is used. Powder (JP-A-6-191833 or JP-A-6-191835) can be used.
[0017]
As the α-alumina powder of the component A2 used in the present invention, various types of alumina powder available on an industrial scale such as Bayer method alumina, electrofused alumina, and alumina obtained by hydrolysis of an organic metal can be used.
[0018]
As the resin component or the rubber component used in the present invention, a resin or rubber having high thermal conductivity is suitable, and examples thereof include an epoxy resin, an imide resin, a polyester resin, a silicone resin, and a silicone rubber. Further, these resins and rubbers can be used as a mixture.
As the epoxy resin, a substance represented by a glycidyl etherified product of a polyphenol compound such as bisphenol A type, phenol novolak, and cresol novolak can be used.
[0019]
The main component of the silicone rubber is not particularly limited as long as it can be vulcanized with a linear organopolysiloxane. For example, a heat vulcanization type comprising dimethylpolysiloxane or vinyl group-containing dimethylpolysiloxane and an organic peroxide can be used. An organopolysiloxane, an addition reaction vulcanization type organopolysiloxane comprising a vinyl group-containing dimethylpolysiloxane, a dimethylhydrogenpolysiloxane having a -SiH group and platinum or a platinum compound as a catalyst, or a mixture thereof is preferably used.
[0020]
In the resin composition or rubber composition of the present invention, various additives such as an inorganic powder other than α-alumina powder, a dispersant, a defoaming agent, a release agent, a flame retardant, and a coloring agent are used in the present invention. Can be added within a range that does not impair the purpose of the above.
[0021]
In the present invention, the method of mixing the α-alumina powder with the resin or rubber is not particularly limited, and it is possible to mix and compound using a general mixer such as a roll, a kneader or a planetary type stirrer. .
[0022]
As a method for sealing an electronic component such as a semiconductor using the resin composition or the rubber composition of the present invention, transfer molding, compression molding, injection molding, or a potting method can be used. , Extrusion molding, injection molding, compression molding, calender roll molding and the like can be used.
[0023]
【Example】
Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.
[0024]
Various measurements in the present invention were performed as follows.
1. Measurement of Primary Particle Size Photographs of the powder particles were taken using an SEM (scanning electron microscope, manufactured by JEOL Ltd .: T-300), and 5 to 10 particles were selected from the photograph to perform image analysis. And the average value was obtained.
[0025]
2. Measurement of particle size distribution The particle size distribution was measured by X-ray transmission sedimentation method using 5000 ET (manufactured by Micromeritics).
[0026]
3. Measurement of BET specific surface area The BET specific surface area was measured using Flowsorb II Model 2300 (manufactured by Micromeritix).
[0027]
Example 1
Γ-alumina powder (trade name: AKP-G15) manufactured by Sumitomo Chemical Co., Ltd. was fired in a 100% hydrogen chloride gas atmosphere at 1100 ° C. for 2 hours to obtain α-alumina powder. The obtained α-alumina powder was composed of polyhedral particles having substantially no fracture surface and having 8 to 20 faces, and the primary particle diameter was 18 μm. As a result of measuring the particle size distribution, D50 was 18 μm, D10 was 14 μm, D90 was 25 μm, the D50 / D10 ratio was 1.3, and the D90 / D10 ratio was 1. It was 8. The BET specific surface area is 0. Since it was 1 m 2 / g, the BET specific surface area diameter was 15 μm, and the value obtained by dividing D50 by the BET specific surface area diameter was 1. It was 2.
[0028]
A BET specific surface area of γ-alumina powder (trade name: AKP-G15) manufactured by Sumitomo Chemical Co., Ltd. was 5. 8 m 2 / g of α-alumina powder (trade name: AKP-30) manufactured by Sumitomo Chemical Co., Ltd. 3 wt% was added to obtain a mixed raw material, and the mixed raw material was fired in a 100% hydrogen chloride gas atmosphere at 1000 ° C. for 1 hour to obtain α-alumina powder. The resulting α-alumina powder was composed of polyhedral particles having substantially no fracture surface and having 8 to 20 faces, and the primary particle diameter was 2 μm. As a result of measuring the particle size distribution, D50 was 2. It was 0 μm. The BET specific surface area is 1. It was 0 m 2 / g.
[0029]
The α-alumina powder having a primary particle diameter of 18 μm and the α-alumina powder having a primary particle diameter of 2 μm are mixed at various ratios, and 2 g of the obtained mixed powder of α-alumina is collected to obtain a gold powder having an inner diameter of 2 cm. The mold was filled and a pressure of 1500 kg / cm 2 was applied by a uniaxial press. The mold was removed from the uniaxial press, and the density of the powder after pressing was calculated from the weight and dimensions. Table 1 shows the results. 2. The density becomes highest when the weight ratio of the α-alumina powder having a primary particle diameter of 18 μm to the α-alumina powder having a primary particle diameter of 2 μm is 80:20. It became 03 g / cm 3 .
[0030]
The α-alumina powder having a primary particle diameter of 18 μm and the α-alumina powder having a primary particle diameter of 2 μm were mixed at a weight ratio of 80:20 to obtain an α-alumina mixed powder, which was mixed with an epoxy resin.
As an epoxy resin, an epoxy resin (trade name: Sumiepoxy ESCN-195-XL) manufactured by Sumitomo Chemical Co., Ltd. was used, and an epoxy curing agent, a curing accelerator, a release agent and a coupling agent were added, and the α- The alumina mixed powder was added so as to be 70% by volume, and kneaded at 110 ° C. with a roll. % By volume means the density of α-alumina. 0 g / cm 3 , and the density of the epoxy resin was 1. It was calculated from the weight as 2 g / cm 3 . The mixture was formed into a plate by transfer molding, and cured by heating to 180 ° C. to produce a composite (molded body). The thermal conductivity of the obtained composite at room temperature (21 ° C.) was measured by a laser flash method and found to be 3.0 W / mK.
[0031]
[Table 1]
Example 2
The α-alumina powder having a primary particle diameter of 18 μm prepared in Example 1 and α-alumina powder (AKP-30) manufactured by Sumitomo Chemical Co., Ltd. were mixed at a weight ratio of 80:20. , Α-alumina mixed powder was obtained. As a result of measuring the particle size distribution of AKP-30, D50 was found to be 0. The value obtained by dividing the D50 of α-alumina having a primary particle diameter of 18 μm by the D50 of AKP-30 was 51 μm. Using the mixed powder as a filler, a composite was prepared in the same manner as in Example 1 except that the addition amount was 75% by volume in an epoxy resin. 4. Thermal conductivity of the obtained composite at room temperature (21 ° C.) was measured by a laser flash method. It was 1 W / mK.
[0033]
Example 3
The α-alumina powder having a primary particle diameter of 18 μm prepared in Example 1 and α-alumina powder (AKP-30) manufactured by Sumitomo Chemical Co., Ltd. were mixed at a weight ratio of 80:20. , Α-alumina mixed powder was obtained. The mixed powder was used as a filler in the same manner as in Example 1 except that the mixed powder was added to an epoxy resin so as to be 80% by volume to prepare a composite. 7. The thermal conductivity of the obtained composite at room temperature (21 ° C.) was measured by a laser flash method. It was 9 W / mK.
[0034]
Comparative Example 1
The fused alumina WA # 800 and WA # 6000 manufactured by Fujimi Incorporated were mixed at various ratios, and the powder density after pressing was measured in the same manner as in Example 1. Table 2 shows the measurement results. WA # 800 is α-alumina powder composed of irregular particles having a fractured surface, D50 is 15 μm, D10 is 11 μm, D90 is 17 μm, and the D50 / D10 ratio is 1. 4. The D90 / D10 ratio is 1. It was 6. The BET specific surface area is 0. Since it was 2 m 2 / g, the BET specific surface area diameter was 7. 5 μm, and the value obtained by dividing D50 by the BET specific surface area diameter is 2. It was 0. WA # 6000 is an α-alumina powder composed of irregular particles having a fractured surface, and has a D50 of 1. 8 μm, and the value obtained by dividing the D50 of WA # 800 by the D50 ratio of WA # 6000 is 8. It was 3. The BET specific surface area of WA # 6000 is 3. It was 7 m 2 / g.
[0035]
WA # 800 and WA # 6000 were mixed at a weight ratio of 80:20 and added as a filler to the epoxy resin in the same manner as in Example 1. However, when the total amount of alumina added was 70% by volume, epoxy The mixture of the resin and the α-alumina powder did not become a fluid mixture, and transfer molding was not possible. A composite was produced in the same manner as in Example 1 except that the total amount of added alumina was 60% by volume. The thermal conductivity of the obtained composite at room temperature (21 ° C.) was measured by a laser flash method and found to be 1.6 W / mK.
[0036]
[Table 2]
Comparative Example 2
As a result of measuring the thermal conductivity at room temperature (21 ° C.) of the epoxy resin used in Example 1 without molding α-alumina powder without blending α-alumina powder by a laser flash method, it was found that the epoxy resin was 0.1%. It was 2 W / mK.
[0038]
【The invention's effect】
The α-alumina powder-containing resin composition or rubber composition of the present invention has high thermal conductivity, is an electrically insulating material having excellent moldability, and has a heat conductive sealing material and a heat conductive adhesive. Suitable for applications such as heat dissipation sheets.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31669094A JP3572692B2 (en) | 1994-12-20 | 1994-12-20 | α-Alumina powder-containing resin composition and rubber composition |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31669094A JP3572692B2 (en) | 1994-12-20 | 1994-12-20 | α-Alumina powder-containing resin composition and rubber composition |
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| JPH08169980A JPH08169980A (en) | 1996-07-02 |
| JP3572692B2 true JP3572692B2 (en) | 2004-10-06 |
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| JP2007070492A (en) * | 2005-09-07 | 2007-03-22 | Hitachi Ltd | Heat conductive grease, adhesive and elastomer composition, and cooling device |
| WO2007105741A1 (en) | 2006-03-10 | 2007-09-20 | Teijin Chemicals Ltd. | Multilayer body |
| CN105658715B (en) * | 2013-10-24 | 2017-11-28 | Dic株式会社 | Resin combination, heat sink material and radiating component |
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