JP4833398B2 - Method for producing thermally conductive molded body - Google Patents
Method for producing thermally conductive molded body Download PDFInfo
- Publication number
- JP4833398B2 JP4833398B2 JP2000281703A JP2000281703A JP4833398B2 JP 4833398 B2 JP4833398 B2 JP 4833398B2 JP 2000281703 A JP2000281703 A JP 2000281703A JP 2000281703 A JP2000281703 A JP 2000281703A JP 4833398 B2 JP4833398 B2 JP 4833398B2
- Authority
- JP
- Japan
- Prior art keywords
- thermally conductive
- graphitized carbon
- carbon fiber
- conductive molded
- molded body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/10—Bump connectors; Manufacturing methods related thereto
- H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
- H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
- H01L2224/161—Disposition
- H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
- H01L2224/732—Location after the connecting process
- H01L2224/73251—Location after the connecting process on different surfaces
- H01L2224/73253—Bump and layer connectors
Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Inorganic Fibers (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Description
【0001】
【発明の属する技術分野】
本発明は、優れた熱伝導性を有する熱伝導性成形体の製造方法に関するものである。さらに詳しくは、電子機器等において半導体素子や電源、光源などの電子部品が発生する熱を効果的に外部へ放散させるための放熱部材、伝熱部材あるいはそれらの構成材料として好適な熱伝導性成形体の製造方法に関するものである。
【0002】
【従来の技術】
近年、電子機器においては、高性能化、小型化及び軽量化に伴う半導体パッケージの高密度実装化、LSIの高集積化及び高速化によって、各種の電子部品で発生する熱を効果的に外部へ放散させる熱対策が非常に重要な課題になっている。従来、この熱対策として、プリント配線基板、半導体パッケージ、放熱板、筐体等を熱伝導性に優れる材料(熱伝導性高分子組成物)で形成すること、放熱板等の放熱部材と発熱源との間に熱伝導性を有する高分子グリスや前記熱伝導性高分子組成物よりなるシート材(熱伝導性成形体)を介在させることなどが実施されている。
【0003】
従来の熱伝導性高分子組成物及び熱伝導性成形体としては、高分子材料に熱伝導性充填剤として、酸化アルミニウムや窒化ホウ素、窒化アルミニウム、酸化マグネシウム、酸化亜鉛、炭化ケイ素、石英、水酸化アルミニウムなどの金属酸化物、金属窒化物、金属炭化物、金属水酸化物などを充填したものが知られている。
【0004】
また、炭素繊維や黒鉛粉末を熱伝導性充填剤として配合した熱伝導性高分子組成物及び熱伝導性成形体も知られている。具体的には、黒鉛粉末を熱可塑性樹脂に充填した熱伝導性樹脂成形品(特開昭62−131033号公報)、カーボンブラックや黒鉛などを含有するポリエステル樹脂組成物(特開平4−246456号公報)、一方向に引揃えた炭素繊維に黒鉛粉末と熱硬化性樹脂を含浸した機械的強度の高い熱伝導性成形品(特開平5−17593号公報)、断面構造を特定したピッチ系炭素繊維を利用した熱伝導性材料(特開平5−222620号公報)、粒径1〜20μmの人造黒鉛を配合したゴム組成物(特開平5−247268号公報)、特定のアスペクト比の黒鉛化炭素繊維をシリコーンゴムなどの高分子に分散した熱伝導性シート(特開平9−283955号公報)、結晶面間隔が0.330〜0.340nmの球状黒鉛粉末をシリコーンゴムに配合した組成物及び放熱シート(特開平10−298433号公報)、特定の加熱処理を施した黒鉛微粒子をシリコーンゴムに配合した導電性と熱伝導性とを有するシリコーンゴム組成物(特開平11−158378号公報)、特定長さの炭素繊維をシリコーンゴムに配合した導電性と熱伝導性に優れる組成物(特開平11−279406号公報)等である。
【0005】
【発明が解決しようとする課題】
ところが、発熱量が一段と増大し続ける最近の電子機器においては、熱対策として適用される熱伝導性高分子組成物及び熱伝導性成形体に、より一層優れた熱伝導性が要求されており、上述した従来の熱伝導性高分子組成物及び熱伝導性成形体では、そのニーズに十分応えることができないという問題があった。
【0006】
本発明は、上記のような従来技術に存在する問題点に着目してなされたものである。その目的とするところは、優れた熱伝導性を有し、電子機器等における放熱部材、伝熱部材あるいはそれらの構成材料として好適な熱伝導性成形体の製造方法を提供することにある。
【0007】
【課題を解決するための手段】
上記の目的を達成するために、請求項1に記載の発明は、X線回折法による黒鉛層間の面間隔(d002)が0.3370nm未満で、かつ、(101)回折ピークと(100)回折ピークのピーク強度比(P101/P100)が1.15以上であるとともに強磁性体で被覆されていない黒鉛化炭素繊維と、高分子材料とを含有する熱伝導性高分子組成物に対して磁束密度2テスラ以上の磁場を印加し、前記黒鉛化炭素繊維を一定方向に配向させた状態で前記熱伝導性高分子組成物を固化させることを要旨とする。
【0008】
請求項2に記載の発明は、請求項1に記載の熱伝導性成形体の製造方法において、前記黒鉛化炭素繊維は、メソフェーズピッチを原料に用いて紡糸、不融化及び炭化の各処理を順次行った後に粉砕し、その後黒鉛化して得られるものであり、その繊維直径が5〜20μm、平均粒径が5〜500μmであることを要旨とする。
【0010】
【発明の実施の形態】
以下、本発明を具体化した実施形態を詳細に説明する。
本実施形態における熱伝導性成形体は、高分子材料と、熱伝導性充填剤として黒鉛化炭素繊維とを含有する熱伝導性高分子組成物を所定の形状に成形したものであり、その熱伝導性成形体中における黒鉛化炭素繊維は一定方向に配向している。
【0011】
まず、熱伝導性充填剤として用いられる黒鉛化炭素繊維について説明する。
ここで用いられる黒鉛化炭素繊維は、X線回折法による黒鉛層間の面間隔(d002)が0.3370nm未満で、かつ、(101)回折ピークと(100)回折ピークのピーク強度比(P101/P100)が1.15以上である。面間隔(d002)が0.3370nm以上又はピーク強度比(P101/P100)が1.15未満の場合は、得られる熱伝導性成形体に十分な熱伝導性を持たせることができず不適当である。尚、黒鉛層間の面間隔(d002)の下限値は、理論値として算出される0.3354nmであり、ピーク強度比(P101/P100)の上限値は、3である。
【0012】
ここで、X線回折法とは、X線源にCuKα、標準物質に高純度シリコンを使用して回折パターンを測定するものである。面間隔(d002)は、(002)回折パターンのピーク位置と半値幅から求められる。また、ピーク強度比(P101/P100)は、得られた回折線図にベースラインを引き、このベースラインから(101)(2θ≒44.5度)、(100)(2θ≒42.5度)の各ピークの高さ(P101)、(P100)を測定し、(P101)を(P100)で除して求められる。
【0013】
黒鉛化炭素繊維の原料としては、例えば、ナフタレンやフェナントレン等の縮合多環炭化水素化合物、石油系ピッチや石炭系ピッチ等の縮合複素環化合物等が挙げられる。その中でも石油系ピッチ又は石炭系ピッチが好ましく、特に光学的異方性ピッチ、すなわちメソフェーズピッチが好ましい。これらは、一種を単独で用いても、二種以上を適宜組み合わせて用いてもよいが、メソフェーズピッチを単独で用いること、すなわちメソフェーズピッチ含有量100%の黒鉛化炭素繊維が最も好ましい。
【0014】
黒鉛化炭素繊維の形態としては、繊維状(繊維状の形態が維持された粉砕品や切断品も含む)、ウィスカー状、マイクロコイル状、ナノチューブ状等が挙げられるが、特に限定されない。
【0015】
黒鉛化炭素繊維の繊維直径は、好ましくは5〜20μm、より好ましくは5〜15μm、特に好ましくは8〜12μmである。繊維直径が5μmよりも小さかったり20μmよりも大きいと、生産性が低下するため好ましくない。
【0016】
黒鉛化炭素繊維の平均粒径は、好ましくは5〜500μm、より好ましくは15〜100μm、特に好ましくは15〜45μmである。平均粒径が5μmよりも小さいと、黒鉛化炭素繊維同士の接触が少なくなって熱の伝導経路が不十分になるために、熱伝導性成形体の熱伝導性が低下する。逆に平均粒径が500μmよりも大きいと、黒鉛化炭素繊維が嵩高くなるために高分子材料中に高濃度で充填させることが困難となる。尚、黒鉛化炭素繊維の平均粒径の値は、レーザー回折方式による粒度分布から算出することができる。
【0017】
黒鉛化炭素繊維の熱伝導率は特に限定されないが、繊維の長さ方向における熱伝導率で400W/m・K以上が好ましく、800W/m・K以上がより好ましく、1000W/m・K以上が特に好ましい。
【0018】
黒鉛化炭素繊維は、電解酸化などによる酸化処理によって、あるいはカップリング剤やサイジング剤で処理することによって表面を改質させたものでもよい。この場合には、高分子材料との濡れ性や充填性を向上させたり、界面の剥離強度を改良したりすることができる。また、無電解メッキ法、電解メッキ法、真空蒸着、スパッタリング、イオンプレーティングなどの物理的蒸着法、化学的蒸着法、塗装、浸漬、微細粒子を機械的に固着させるメカノケミカル法などの方法によって金属やセラミックスを表面に被覆させたものでもよい。
【0019】
次に、高分子材料について説明する。
高分子材料としては、例えば、熱可塑性樹脂、熱可塑性エラストマー、熱硬化性樹脂、架橋ゴム等が挙げられる。
【0020】
熱可塑性樹脂としては、ポリエチレン、ポリプロピレン、エチレン−プロピレン共重合体等のエチレン−α−オレフィン共重合体、ポリメチルペンテン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリ酢酸ビニル、エチレン−酢酸ビニル共重合体、ポリビニルアルコール、ポリアセタール、フッ素樹脂(ポリフッ化ビニリデン、ポリテトラフルオロエチレン等)、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエチレンナフタレート、ポリスチレン、ポリアクリロニトリル、スチレン−アクリロニトリル共重合体、ABS樹脂、ポリフェニレンエーテル(PPE)樹脂、変性PPE樹脂、脂肪族ポリアミド類、芳香族ポリアミド類、ポリイミド、ポリアミドイミド、ポリメタクリル酸類(ポリメタクリル酸メチル等のポリメタクリル酸エステル)、ポリアクリル酸類、ポリカーボネート、ポリフェニレンスルフィド、ポリサルホン、ポリエーテルサルホン、ポリエーテルニトリル、ポリエーテルケトン、ポリケトン、液晶ポリマー、アイオノマー等が挙げられる。
【0021】
熱可塑性エラストマーとしては、スチレン−ブタジエン共重合体及びスチレン−イソプレンブロック共重合体とそれらの水添物、スチレン系熱可塑性エラストマー、オレフィン系熱可塑性エラストマー、塩化ビニル系熱可塑性エラストマー、ポリエステル系熱可塑性エラストマー、ポリウレタン系熱可塑性エラストマー、ポリアミド系熱可塑性エラストマー等が挙げられる。
【0022】
熱硬化性樹脂としては、エポキシ樹脂、ポリイミド樹脂、ビスマレイミド、ベンゾシクロブテン、フェノール樹脂、不飽和ポリエステル樹脂、ジアリルフタレート、シリコーン樹脂、ポリウレタン、ポリイミドシリコーン、熱硬化型PPE樹脂、熱硬化型変性PPE樹脂等が挙げられる。
【0023】
架橋ゴムとしては、天然ゴム、ブタジエンゴム、イソプレンゴム、スチレン−ブタジエン共重合ゴム、ニトリルゴム、水添ニトリルゴム、クロロプレンゴム、エチレン−プロピレン共重合ゴム、塩素化ポリエチレン、クロロスルホン化ポリエチレン、ブチルゴム、ハロゲン化ブチルゴム、フッ素ゴム、ウレタンゴム、シリコーンゴム等が挙げられる。
【0024】
これらの高分子材料の中でも耐熱性などの温度特性及び電気的信頼性の点から、シリコーンゴム、エポキシ樹脂、ポリウレタン、不飽和ポリエステル、ポリイミド、ビスマレイミド樹脂、ベンゾシクロブテン樹脂、フッ素樹脂、PPE樹脂及び熱可塑性エラストマーより選ばれる少なくとも一種が好ましい。これらの高分子材料は、一種を単独で用いても、二種以上を適宜組み合わせて用いてもよく、二種以上の高分子材料からなるポリマーアロイを使用してもよい。また、高分子材料の架橋方法については特に限定されず、熱硬化、光硬化、湿気硬化等、公知の架橋方法を採用することができる。
【0025】
尚、これらの高分子材料は用途や要求性能に応じて適宜選択して用いられる。例えば誘電率、誘電正接が小さく、かつ高周波領域での周波数特性を要求される配線基板用途には、フッ素樹脂、熱硬化型PPE樹脂、熱硬化型変性PPE樹脂及びポリオレフィン系樹脂が好ましい。また、接着剤用途には、エポキシ樹脂、ポリイミド、アクリル樹脂等の接着性高分子が好ましい。
【0026】
続いて、上記の黒鉛化炭素繊維と高分子材料とを含有する熱伝導性高分子組成物、及びその熱伝導性高分子組成物を所定の形状に成形した熱伝導性成形体について説明する。
【0027】
熱伝導性高分子組成物に含まれる高分子材料と黒鉛化炭素繊維の比は、目的とする最終製品の要求性能によって適宜決定されるが、100重量部の高分子材料に対して黒鉛化炭素繊維を5〜500重量部とするのが好ましく、40〜300重量部がより好ましい。黒鉛化炭素繊維の配合量が5重量部よりも少ないと、得られる熱伝導性成形体の熱伝導率が小さくなって放熱特性が低下する。逆に500重量部を超えると、配合組成物の粘度が増大して黒鉛化炭素繊維を均一に分散させることが困難になり、また気泡の混入が避けられず好ましくない。
【0028】
さらに熱伝導性高分子組成物には、上述の黒鉛化炭素繊維の他に、その他の熱伝導性充填剤、難燃材、軟化剤、着色材、安定剤等を必要に応じて配合してもよい。その他の熱伝導性充填剤としては、金属やセラミックス、具体的には、銀、銅、金、酸化アルミニウム、酸化マグネシウム、窒化ホウ素、窒化アルミニウム、窒化ケイ素、炭化ケイ素、水酸化アルミニウムのほか、金属被覆樹脂、上述の黒鉛化炭素繊維以外の黒鉛化炭素繊維、黒鉛化されていない炭素繊維、天然黒鉛、人造黒鉛、メソカーボンマイクロビーズ等が挙げられる。また、その形態としては、球状、粉状、繊維状、針状、鱗片状、ウィスカー状、マイクロコイル状、単層ナノチューブ、多層ナノチューブ状等が挙げられる。尚、最終製品として特に電気絶縁性が要求される用途においては、酸化アルミニウム、酸化マグネシウム、窒化ホウ素、窒化アルミニウム、窒化ケイ素、炭化ケイ素、水酸化アルミニウム等の電気絶縁性の充填剤が好ましい。また、揮発性の有機溶剤や低粘度の軟化剤、反応性可塑剤を添加してもよく、これらを添加した場合には熱伝導性高分子組成物の粘度を低下させることができ、黒鉛化炭素繊維を一定方向に配向させやすくすることができる。
【0029】
シート状に成形した熱伝導性成形体(熱伝導性シート)場合、その硬度は、用途に応じて適宜決定されるが、使用時の応力緩和性と追随性に関しては柔軟なほど、すなわち低硬度ほど有利である。具体的な硬度としては、ショアA硬度で70以下が好ましく、40以下がより好ましく、アスカーC硬度で30以下のゲル状のシリコーンゴムや熱可塑性エラストマーを高分子材料として使用したものが特に好ましい。また、厚みも特に限定されないが、好ましくは50μm〜10mm、より好ましくは200μm〜5mmである。50μmよりも薄いと製造しにくく、また取り扱いにくい。10mmよりも厚くなると熱抵抗が大きくなるので好ましくない。
【0030】
次に、熱伝導性成形体の使用方法を説明する。
熱伝導性成形体は、電子機器等において半導体素子や電源、光源などの電子部品が発生する熱を効果的に外部へ放散させるための放熱部材、伝熱部材あるいはそれらの構成材料等として用いられる。具体的には、シート状に加工して半導体素子等の発熱部材と放熱器等の放熱部材との間に介在させて用いたり、放熱板、半導体パッケージ用部品、ヒートシンク、ヒートスプレッダー、ダイパッド、プリント配線基板、冷却ファン用部品、ヒートパイプ、筐体等に成形加工して用いたりする。
【0031】
図1は、シート状の熱伝導性成形体を伝熱部材として用いた例を示す図である。図1(a)に示す例では、半導体素子11(ボールグリッドアレイ型半導体パッケージ)と放熱板12との間に熱伝導性成形体13が介在されている。図1(b)に示す例では、半導体素子11(チップサイズ型半導体パッケージ)とプリント配線基板14との間に熱伝導性成形体13が介在されている。図1(c)に示す例では、半導体素子11(ピングリッドアレイ型半導体パッケージ)とヒートシンク15との間に熱伝導性成形体13が介在されている。図1(d)に示す例では、複数の半導体素子11と筐体16との間に熱伝導性成形体13が介在されている。また図2は、プリント配線基板14を熱伝導性成形体で構成した例を示す図である。同図に示すプリント配線基板14は、熱伝導性高分子組成物を板状に成形した基板17を備え、その基板17上には銅箔などからなる導電層18が形成されている。
【0032】
次に、熱伝導性成形体の製造方法を説明する。
ピッチを原料とする繊維状(繊維状の形態が維持された粉砕品や切断品)の黒鉛化炭素繊維は、紡糸、不融化及び炭化の各処理を順次行った後に粉砕又は切断し、その後黒鉛化して製造される。尚、粉砕又は切断は、炭化の後に限定されるものでなく、不融化の後に行っても、黒鉛化の後に行ってもよいが、炭化の後が最も好ましい。黒鉛化後に粉砕又は切断した場合には、繊維軸方向に発達した黒鉛層面に沿って開裂が生じやすく、破断面表面積の割合が大きくなって熱伝導性が低下するため好ましくない。
【0033】
紡糸工程における紡糸方法としては、メルトスピニング法、メルトブロー法、遠心紡糸法、渦流紡糸法等が挙げられるが、紡糸時の生産性や得られる黒鉛化炭素繊維の品質の観点からメルトブロー法が好ましい。またメルトブロー法の場合、数十ポイズ以下の低粘度で紡糸し、かつ高速冷却することによって、黒鉛層面が繊維軸に平行に配列しやすくなるという利点もある。
【0034】
メルトブロー法の場合、紡糸孔の直径は0.1〜0.5mmが好ましく、0.15〜0.3mmがより好ましい。紡糸孔の直径が0.1mmよりも小さいと目詰まりが生じやすく、また紡糸ノズルの製作が困難になるため好ましくない。逆に0.5mmを超えると、繊維直径が25μm以上と大きくなりやすく、また繊維直径がばらつきやすくなり品質管理上も好ましくない。紡糸速度は、生産性の面から毎分500m以上が好ましく、毎分1500mm以上がより好ましく、毎分2000m以上が特に好ましい。紡糸温度は、原料ピッチの軟化点以上でピッチが変質しない温度以下であればよいが、通常は300〜400℃、好ましくは300〜380℃である。前記紡糸温度との関係から、原料ピッチの軟化点は230〜350℃が好ましく、250〜310℃がより好ましい。
【0035】
不融化工程における不融化処理の方法としては、二酸化窒素や酸素等の酸化性ガス雰囲気中で加熱処理する方法、硝酸やクロム酸等の酸化性水溶液中で処理する方法、光やγ線等により重合処理する方法等が挙げられるが、空気中で加熱処理する方法が簡便なことから好ましい。空気中で加熱処理する方法を採る場合、好ましくは3℃/分以上、より好ましくは5℃/分以上の平均昇温速度で、350℃程度まで昇温させながら加熱処理することが望ましい。
【0036】
続く炭化工程における炭化処理及び黒鉛化工程における黒鉛化処理は、不活性ガス雰囲気中で加熱処理することによって行われる。炭化処理の際の処理温度は好ましくは250〜1500℃、より好ましくは500〜900℃である。また黒鉛化処理の際の処理温度は好ましくは2500℃以上、より好ましくは3000℃以上である。
【0037】
粉砕又は切断処理には、ビクトリーミル、ジェットミル、高速回転ミル等の粉砕機、又はチョップド繊維で用いられる切断機等が使用される。粉砕又は切断を効率よく行うためには、ブレードを取付けたロータを高速に回転させることにより、繊維軸に対して直角方向に繊維を寸断する方法が適切である。この粉砕又は切断処理によって生じる黒鉛化炭素繊維の平均粒径は、ロータの回転数、ブレードの角度等を調整することにより制御される。尚、繊維の粉砕方法としてはボールミル等の磨砕機による方法もあるが、この方法の場合、繊維の直角方向への加圧力が働いて繊維軸方向への縦割れの発生が多くなるので不適当である。
【0038】
上記のようにして得られた黒鉛化炭素繊維と高分子材料とを混合し、必要に応じて脱泡操作などを行うことで、熱伝導性高分子組成物が得られる。この混合の際には、ブレンダー、ミキサー、ロール、押出機などの混合装置又は混練装置を使用してもよい。そして、得られた熱伝導性高分子組成物を、所定の形状に成形することで熱伝導性成形体が得られ、特にシート状に成形した場合には熱伝導性シートが得られる。この成形の方法としては、プレス成形法、押出成形法、射出成形法、注型成形法、ブロー成形法、カレンダー成形法などが挙げられるほか、熱伝導性高分子組成物が液状の場合には、塗装法、印刷法、ディスペンサー法、ポッティング法などが挙げられる。また、シート状に成形する場合には、圧縮成形法、注型成形法、押出成形法、ブレード成形法、カレンダー成形法が好ましい。
【0039】
熱伝導性高分子組成物中における黒鉛化炭素繊維を一定方向に配向させる方法としては、流動場又はせん断場を利用する方法、磁場を利用する方法、電場を利用する方法等が挙げられる。その中でも、黒鉛化炭素繊維の比較的大きい異方性磁化率を利用して、熱伝導性高分子組成物に外部から強磁場を印加して黒鉛化炭素繊維を磁力線と平行に配向させる方法が、効率的で、なおかつ配向方向を任意に設定できることから好ましい。
【0040】
磁場配向を利用して熱伝導性成形体を製造する場合には、金型のキャビティ内に注入された前記熱伝導性高分子組成物に対して磁場を印加し、その熱伝導性高分子組成物中に含まれる黒鉛化炭素繊維を一定方向に配向させた状態で熱伝導性高分子組成物を固化させる。
【0041】
例えば図3に示すような板状の熱伝導性成形体21において黒鉛化炭素繊維を厚み方向(図3におけるZ軸方向)に配向させる場合には、図4(a)に示すように、磁力線Mの向きが熱伝導性成形体21(図3参照)の厚み方向に一致するように磁場発生手段22を配置して、金型23のキャビティ23a内に注入された熱伝導性高分子組成物24に対して磁場を印加する。また、熱伝導性成形体21の面内方向(図3におけるX軸方向、Y軸方向等)に黒鉛化炭素繊維を配向させる場合には、図4(b)に示すように、磁力線Mの向きが熱伝導性成形体21(図3参照)の面内方向に一致するように磁場発生手段22を配置して、金型23のキャビティ23a内に注入された熱伝導性高分子組成物24に対して磁場を印加する。
【0042】
尚、図4(a),(b)に示す例では、一対の磁場発生手段22を金型23を間に挟んで配置させるようにしたが、各例において一方の磁場発生手段22を省略してもよい。また、図4(a),(b)に示す例では、互いのS極とN極とが対向するように一対の磁場発生手段22を配置したが、S極同士又はN極同士が対向するように一対の磁場発生手段22を配置してもよい。さらに、磁力線Mは必ずしも直線状でなくてもよく、曲線状や矩形状でもよい。また、磁力線Mが一方向だけでなく2方向以上に延びるように磁場発生手段22を配置してもよい。
【0043】
前記磁場発生手段22としては、永久磁石、電磁石等が挙げられる。磁場発生手段22によって形成される磁場の磁束密度は、0.05〜30テスラの範囲が好ましく、0.5テスラ以上がより好ましく、2テスラ以上が特に好ましい。
【0044】
以上詳述した本実施形態によれば次のような効果が発揮される。
・ 熱伝導性成形体に含まれる黒鉛化炭素繊維のX線回折法による黒鉛層間の面間隔(d002)を0.3370nm未満とし、さらにピーク強度比(P101/P100)を1.15以上とすることにより、熱伝導性成形体の熱伝導性を大幅に改善させることができる。このため、本実施形態における熱伝導性成形体は優れた熱伝導性を発揮することができ、電子機器等における放熱部材、伝熱部材あるいはそれらの構成材料として好適に用いることができる。熱伝導性が大幅に改善される理由は定かではないが、黒鉛化炭素繊維を高分子材料中に分散させた場合、熱の伝達経路が黒鉛化炭素繊維のミクロ構造と非常に強く相関しているものと考えられる。
【0045】
・ 黒鉛化炭素繊維は繊維の長さ方向における熱伝導性が非常に優れている。従って、黒鉛化炭素繊維が配合された熱伝導性成形体では、黒鉛化炭素繊維を一定方向に配向させることによってその配向方向における熱伝導性を著しく向上させることができ、熱伝導性に異方性を有する熱伝導性成形体を得ることができる。
【0046】
・ 黒鉛化炭素繊維の原料としてメソフェーズピッチを用いることにより、得られる熱伝導性成形体の熱伝導性をさらに向上させることができる。また、メソフェーズピッチ含有量100%の黒鉛化炭素繊維、すなわち黒鉛化炭素繊維の原料としてメソフェーズピッチのみを用いた場合には、紡糸性、品質の安定性をも向上させることができる。
【0047】
・ 黒鉛化炭素繊維の繊維直径は5〜20μm、平均粒径は5〜500μmとすることにより、高分子材料に高濃度で充填させることできるとともに、得られる熱伝導性成形体の熱伝導性を向上させることができる。また工業的に生産も容易である。
【0048】
・ 粉砕又は切断を紡糸、不融化及び炭化の各処理を順次行った後に行うようにすることで、繊維の縦割れを抑制することができる。さらには、黒鉛化処理の際、粉砕又は切断して新たに露出した面において縮重合反応、環化反応が進みやすい傾向にあることから、熱伝導性に優れた黒鉛化炭素繊維を得やすいという利点もある。
【0049】
・ 熱伝導性高分子組成物に対して外部から磁場を印加して、その熱伝導性高分子組成物中に含まれる黒鉛化炭素繊維を一定方向に配向させ、その状態で熱伝導性高分子組成物を固化させるようにしたため、黒鉛化炭素繊維を効率的に配向させることができるとともに、その配向方向を任意に設定することができる。
【0050】
【実施例】
次に、実施例及び比較例を挙げて前記実施形態をさらに具体的に説明する。
(黒鉛化炭素繊維の試作例1)
光学異方性で比重1.25の石油系メソフェーズピッチを原料として、幅3mmのスリットの中に直径0.2mmφの紡糸孔を有するダイスを使用し、スリットから加熱空気を噴出させて、紡糸温度360℃で溶融ピッチを牽引して平均直径13μmのピッチ系繊維を製造した。紡出された繊維をベルト上に捕集してマットとし、空気中で室温から300℃まで平均昇温速度6℃/分で昇温して不融化処理した。引続き、この不融化処理繊維を700℃で軽度に炭化処理した後、高速回転ミルで粉砕して炭素繊維粉砕品を得た。この炭素繊維粉砕品を、アルゴン雰囲気下で、2300℃まで昇温後、2300℃で40分間保持し、次いで3℃/分の速度で3000℃まで昇温し、さらに3000℃で1時間保持してから降温し、黒鉛化された炭素繊維粉砕品を製造した。この黒鉛化炭素繊維粉砕品(試作例1)の密度、繊維直径、平均粒径、X線回折パラメータ及び繊維の長さ方向における熱伝導率について測定した結果を表1に示す。尚、繊維の長さ方向における熱伝導率は、粉砕せずマット形状のまま同様の条件で黒鉛化したものを用いて測定した。
【0051】
(黒鉛化炭素繊維の試作例2)
光学異方性で比重1.25の石油系メソフェーズピッチを原料として、幅3mmのスリットの中に直径0.2mmφの紡糸孔を有するダイスを使用し、スリットから加熱空気を噴出させて、紡糸温度360℃で溶融ピッチを牽引して平均直径15μmのピッチ系繊維を製造した。紡出された繊維をベルト上に捕集してマットとし、空気中で室温から300℃まで平均昇温速度6℃/分で昇温して不融化処理した。引続き、この不融化処理繊維を700℃で軽度に炭化処理した後、高速回転ミルで粉砕して炭素繊維粉砕品を得た。この炭素繊維粉砕品をアルゴン雰囲気下で、2300℃まで昇温後、2300℃で40分間保持し、次いで3℃/分の速度で3100℃まで昇温し、さらに3100℃で1時間保持してから降温し、黒鉛化された炭素繊維粉砕品を製造した。この黒鉛化炭素繊維粉砕品(試作例2)の密度、繊維直径、平均粒径、X線回折パラメータ及び繊維の長さ方向における熱伝導率について測定した結果を表1に示す。尚、繊維の長さ方向における熱伝導率は、粉砕せずマット形状のまま同様の条件で黒鉛化したものを用いて測定した。
【0052】
(黒鉛化炭素繊維の試作例3)
三菱化学株式会社製の超高弾性率ピッチ系黒鉛化炭素繊維を高速回転ミルで粉砕して黒鉛化炭素繊維粉砕品(試作例3)を製造した。この黒鉛化炭素繊維粉砕品の密度、繊維直径、平均粒径、X線回折パラメータ及び繊維の長さ方向における熱伝導率について測定した結果を表1に示す。
【0053】
(黒鉛化炭素繊維の試作例4)
日本グラファイトファイバー株式会社製の超高弾性率ピッチ系黒鉛化炭素繊維を高速回転ミルで粉砕して黒鉛化炭素繊維粉砕品(試作例4)を製造した。この黒鉛化炭素繊維粉砕品の密度、繊維直径、平均粒径、X線回折パラメータ及び繊維の長さ方向における熱伝導率について測定した結果を表1に示す。
【0054】
【表1】
(実施例1)
試作例1の黒鉛化炭素繊維をシランカップリング剤で表面処理し、その処理後の黒鉛化炭素繊維125重量部を不飽和ポリエステル樹脂(株式会社日本触媒製エポラック)100重量部に混合し真空脱泡して熱伝導性高分子組成物を調製した。続いて、その熱伝導性高分子組成物を所定の金型のキャビティ内に注入し、磁力線の向きが熱伝導性成形体の厚み方向に一致する磁場(磁束密度10テスラ)を印加して熱伝導性高分子組成物中の黒鉛化炭素繊維を十分に配向させた後に加熱硬化させて、厚み1.5mm×縦20mm×横20mmの板状の熱伝導性成形体を得た。
【0055】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向(Z軸方向)に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ11.5W/m・K、2.7W/m・Kであった。
【0056】
(実施例2)
実施例1において、磁力線の向きが熱伝導性成形体の面内方向(X軸方向)に一致する磁場をキャビティ内の熱伝導性高分子組成物に印加するように変更した。それ以外は実施例1と同様にして板状の熱伝導性成形体を作製した。
【0057】
この熱伝導性成形体中の黒鉛化炭素繊維は面内方向(X軸方向)に揃って配向していた。熱伝導性成形体の厚み方向、面内方向(X軸方向)及び面内方向(Y軸方向)における熱伝導率を測定したところ、それぞれ2.8W/m・K、12.6W/m・K、2.8W/m・Kであった。
【0058】
(実施例3)
試作例2の黒鉛化炭素繊維をシランカップリング剤で表面処理し、その処理後の黒鉛化炭素繊維100重量部を液状エポキシ樹脂(スリーボンド株式会社製 TB2280C)100重量部に混合し真空脱泡して熱伝導性高分子組成物を調製した。続いて、その熱伝導性高分子組成物を所定の金型のキャビティ内に注入し、磁力線の向きが熱伝導性成形体の厚み方向に一致する磁場(磁束密度8テスラ)を印加して熱伝導性高分子組成物中の黒鉛化炭素繊維を十分に配向させた後に加熱硬化させて、厚み3mm×縦20mm×横20mmの板状の熱伝導性成形体を得た。
【0059】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ8.2W/m・K、2.5W/m・Kであった。
【0060】
(実施例4)
実施例3において、磁力線の向きが熱伝導性成形体の面内方向(X軸方向)に一致する磁場をキャビティ内の熱伝導性高分子組成物に印加するように変更した。それ以外は実施例3と同様にして板状の熱伝導性成形体を作製した。
【0061】
この熱伝導性成形体中の黒鉛化炭素繊維は面内方向(X軸方向)に揃って配向していた。熱伝導性成形体の厚み方向、面内方向(X軸方向)及び面内方向(Y軸方向)における熱伝導率を測定したところ、それぞれ2.6W/m・K、9.2W/m・K、2.7W/m・Kであった。
【0062】
(実施例5)
試作例1の黒鉛化炭素繊維をシランカップリング剤で表面処理し、その処理後の黒鉛化炭素繊維110重量部と酸化アルミニウム粉末(昭和電工株式会社製 AS−20)60重量部とを、液状シリコーンゴム(GE東芝シリコーン株式会社製 TSE3070)100重量部に混合し真空脱泡して熱伝導性高分子組成物を調製した。続いて、その熱伝導性高分子組成物を所定の金型のキャビティ内に注入し、磁力線の向きが熱伝導性成形体の厚み方向に一致する磁場(磁束密度12テスラ)を印加して熱伝導性高分子組成物中の黒鉛化炭素繊維を十分に配向させた後に加熱硬化させて、厚み0.5mm×縦20mm×横20mmの板状の熱伝導性成形体(アスカーC硬度17)を得た。
【0063】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ11.6W/m・K、2.9W/m・Kであった。
【0064】
(実施例6)
実施例5において、磁力線の向きが熱伝導性成形体の面内方向(X軸方向)に一致する磁場をキャビティ内の熱伝導性高分子組成物に印加するように変更した。それ以外は実施例5と同様にして板状の熱伝導性成形体(アスカーC硬度17)を作製した。
【0065】
この熱伝導性成形体中の黒鉛化炭素繊維は面内方向(X軸方向)に揃って配向していた。熱伝導性成形体の厚み方向における熱伝導率、面内方向(X軸方向)、面内方向(Y軸方向)における熱伝導率を測定したところ、それぞれ2.1W/m・K、10.8W/m・K、2.5W/m・Kであった。
【0066】
(実施例7)
スチレン系熱可塑性エラストマー(旭化成工業株式会社製 タフテックH1053)100重量部に溶剤としてトルエン2000重量部を加えて溶解し、そこに試作例1の黒鉛化炭素繊維60重量部を混合して熱伝導性高分子組成物を調製した。続いて、その熱伝導性高分子組成物を所定の金型のキャビティ内に注入し、磁力線の向きが熱伝導性成形体の高さ方向に一致する磁場(磁束密度6テスラ)を印加して熱伝導性高分子組成物中の黒鉛化炭素繊維を十分に配向させた後にトルエンを揮発させて加熱乾燥し、高さ40mm×縦20mm×横20mmの熱伝導性成形体を得た。
【0067】
この熱伝導性成形体中の黒鉛化炭素繊維は高さ方向に揃って配向していた。熱伝導性成形体の高さ方向及び面内方向における熱伝導率を測定したところ、それぞれ7.4W/m・K、2.2W/m・Kであった。
【0068】
(比較例1)
実施例1において、熱伝導性高分子組成物を硬化させる際の磁場の印加を省略した。それ以外は実施例1と同様にして板状の熱伝導性成形体を作製した。
【0069】
この熱伝導性成形体中の黒鉛化炭素繊維は一定方向に配向せずランダムに分散していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ1.4W/m・K、4.2W/m・Kであった。
【0070】
(比較例2)
実施例3において、試作例2の黒鉛化炭素繊維に代えて試作例4の黒鉛化炭素繊維を使用するように変更した。それ以外は実施例3と同様にして板状の熱伝導性成形体を作製した。
【0071】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ5.1W/m・K、2.3W/m・Kであった。
【0072】
(比較例3)
実施例5において、熱伝導性高分子組成物を硬化させる際に印加する磁場の磁束密度を1.5テスラに変更した。それ以外は実施例5と同様にして板状の熱伝導性成形体を作製した。
【0073】
この熱伝導性成形体中の黒鉛化炭素繊維は充分に配向しておらず、厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ2.7W/m・K、3.1W/m・Kであった。
【0074】
(比較例4)
実施例5において、試作例1の黒鉛化炭素繊維に代えて試作例3の黒鉛化炭素繊維を使用するように変更するとともに、熱伝導性高分子組成物を硬化させる際に印加する磁場の磁束密度を10テスラに変更した。それ以外は実施例5と同様にして板状の熱伝導性成形体(アスカーC硬度17)を作製した。
【0075】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ8.7W/m・K、2.7W/m・Kであった。
【0076】
(比較例5)
比較例4において、試作例3の黒鉛化炭素繊維に代えて試作例4の黒鉛化炭素繊維を使用するように変更した。それ以外は比較例4と同様にして板状の熱伝導性成形体(アスカーC硬度17)を作成した。
【0077】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ9.3W/m・K、2.8W/m・Kであった。
【0078】
(比較例6)
実施例7において、試作例1の黒鉛化炭素繊維に代えて試作例4の黒鉛化炭素繊維を使用するように変更した。それ以外は実施例7と同様にして板状の熱伝導性成形体を作成した。
【0079】
この熱伝導性成形体中の黒鉛化炭素繊維は厚み方向に揃って配向していた。熱伝導性成形体の厚み方向及び面内方向における熱伝導率を測定したところ、それぞれ5.3W/m・K、2.5W/m・Kであった。
上記の結果より、実施例1〜7並びに比較例2及び比較例4〜6の熱伝導性成形体は、黒鉛化炭素繊維の配向方向における熱伝導率の値が、その他の方向における熱伝導率の値に比べて著しく大きく、熱伝導性に異方性があることが示された。また、その配向方向における熱伝導率の値は、試作例1又は試作例2の黒鉛化炭素繊維を使用した実施例1〜7のほうが、試作例3又は試作例4の黒鉛化炭素繊維を使用した比較例2及び比較例4〜6に比べて大きく、優れた熱伝導性を有することが示された。さらに、磁場を印加しなかった比較例1及び磁場を印加したが磁束密度の小さい比較例3の場合は、黒鉛化炭素繊維が配向していないために熱伝導性に異方性がなく、熱伝導率の値も小さいことが示された。
【0080】
(実施例8)
実施例3の板状の熱伝導性成形体を使って配線基板を作製した。すなわち、実施例3の熱伝導性成形体を基板とし、その基板上に電気絶縁性エポキシ系接着剤を塗布し、厚さ35μmの銅箔をプレスで加圧接着した後、銅箔をエッチングすることにより、基板上に導体回路を形成した。この配線基板上にトランジスタ(株式会社東芝製 TO−220)を半田付けし、反対面を冷却ファンで冷却しながら通電し、トランジスタと配線基板の温度差より熱抵抗を求めたところ、0.18℃/Wであった。
【0081】
(比較例5)
比較例2の板状の熱伝導性成形体を使って実施例8と同様にして配線基板を作製した。この配線基板上にトランジスタ(株式会社東芝製 TO−220)を半田付けし、反対面を冷却ファンで冷却しながら通電し、トランジスタと配線基板の温度差より熱抵抗を求めたところ、0.25℃/Wであった。
【0082】
なお、前記実施形態を次のように変更して構成することもできる。
・ 図1(a)〜(d)に示すプリント配線基板14、図1(c)に示すヒートシンク15及び図1(d)に示す筐体16を熱伝導性成形体で構成してもよい。この場合、熱の放散効果を高めることができる。
【0083】
・ 前記実施形態における黒鉛化炭素繊維に加えて、下記の(A)と(B)の2種の黒鉛化炭素繊維うちの少なくとも一方をさらに熱伝導性充填剤として含有させて熱伝導性高分子組成物を構成するように変更してもよい。
【0084】
(A)メソフェーズピッチを原料に用いて紡糸、不融化及び炭化の各処理を順次行った後に粉砕し、その後黒鉛化して得られる黒鉛化炭素繊維。
(B)平均粒径が500μm以下であり、かつ下記(1)及び(2)の物性を備えた黒鉛化炭素繊維。
【0085】
(1)レーザー回折法で測定される粒度分布
10%累積径(μm): 6〜 20
50%累積径(μm):15〜 40
90%累積径(μm):40〜150
(2)タップ密度(g/cm3):0.6〜1.5
(A)に示す黒鉛化炭素繊維を含ませた場合には、熱伝導性成形体の熱伝導性を相乗的に向上させることができる。また、(B)に示す黒鉛化炭素繊維を含ませた場合には、熱伝導性成形体の熱伝導性を相乗的に向上させるとともに加工性も向上させることができる。
【0090】
【発明の効果】
本発明は、以上のように構成されているため、次のような効果を奏する。
請求項1に記載の発明によれば、優れた熱伝導性を発揮することができ、電子機器等における放熱部材、伝熱部材あるいはそれらの構成材料として好適に用いることができる熱伝導性成形体の製造方法が提供される。また、優れた熱伝導性を有する熱伝導性成形体を効率的に製造することができる。
【0091】
請求項2に記載の発明によれば、請求項1に記載の発明の効果に加え、熱伝導性をさらに向上させることができる。
【図面の簡単な説明】
【図1】 (a)〜(d)は熱伝導性成形体の適用例を示す側面図。
【図2】 同じく熱伝導性成形体の適用例を示す断面図。
【図3】 四角板状の熱伝導性成形体を示す斜視図。
【図4】 (a),(b)は熱伝導性成形体の製造方法を示す概念図。
【符号の説明】
13,21…熱伝導性成形体、17…熱伝導性成形体としての基板。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermally conductive molded article having excellent thermal conductivity.Manufacturing methodIt is about. More specifically, heat conductive molding suitable as a heat radiating member, heat transfer member, or constituent material for effectively radiating heat generated by electronic components such as semiconductor elements, power supplies, and light sources to the outside in electronic devices and the like.the body'sIt relates to a manufacturing method.
[0002]
[Prior art]
In recent years, in electronic devices, the heat generated by various electronic components has been effectively transferred to the outside through high-density mounting of semiconductor packages, high integration of LSIs, and high-speed processing due to high performance, miniaturization, and weight reduction. Measures to dissipate heat are a very important issue. Conventionally, as a heat countermeasure, a printed wiring board, a semiconductor package, a heat sink, a housing, etc. are formed of a material having excellent thermal conductivity (thermal conductive polymer composition), a heat dissipation member such as a heat sink, and a heat source. In the meantime, a polymer grease having thermal conductivity or a sheet material (thermally conductive molded body) made of the thermal conductive polymer composition is interposed.
[0003]
Conventional thermal conductive polymer compositions and thermal conductive molded articles include aluminum oxide, boron nitride, aluminum nitride, magnesium oxide, zinc oxide, silicon carbide, quartz, water as a thermal conductive filler in polymer materials. A material filled with a metal oxide such as aluminum oxide, a metal nitride, a metal carbide, or a metal hydroxide is known.
[0004]
In addition, a thermally conductive polymer composition and a thermally conductive molded body in which carbon fiber or graphite powder is blended as a thermally conductive filler are also known. Specifically, a thermally conductive resin molded product in which a graphite powder is filled in a thermoplastic resin (Japanese Patent Laid-Open No. 62-133103), a polyester resin composition containing carbon black, graphite, or the like (Japanese Patent Laid-Open No. 4-246456). Gazette), heat-conductive molded article with high mechanical strength, in which carbon fiber aligned in one direction is impregnated with graphite powder and thermosetting resin (Japanese Patent Laid-Open No. 5-17593), pitch-based carbon with a specified cross-sectional structure Thermally conductive material using fibers (JP-A-5-222620), rubber composition containing artificial graphite having a particle size of 1 to 20 μm (JP-A-5-247268), graphitized carbon having a specific aspect ratio A thermally conductive sheet (Japanese Patent Laid-Open No. 9-283955) in which fibers are dispersed in a polymer such as silicone rubber, and spherical graphite powder having a crystal plane spacing of 0.330 to 0.340 nm are made of silicone rubber. A composition and a heat-dissipating sheet (Japanese Patent Laid-Open No. 10-298433), a silicone rubber composition having electrical conductivity and thermal conductivity obtained by blending specific heat-treated graphite fine particles with silicone rubber (Japanese Patent Laid-Open No. No. 158378), a composition excellent in electrical conductivity and thermal conductivity in which carbon fibers having a specific length are blended with silicone rubber (Japanese Patent Laid-Open No. 11-279406).
[0005]
[Problems to be solved by the invention]
However, in recent electronic devices in which the calorific value continues to increase further, even better thermal conductivity is required for the thermally conductive polymer composition and thermally conductive molded body applied as a heat countermeasure, The conventional heat conductive polymer composition and the heat conductive molded body described above have a problem that the needs cannot be sufficiently met.
[0006]
The present invention has been made paying attention to the problems existing in the prior art as described above. The purpose is to have excellent thermal conductivity, heat conductive molding suitable for heat radiating members, heat transfer members or their constituent materials in electronic devices, etc.the body'sIt is to provide a manufacturing method.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that the interplanar spacing (d002) between graphite layers by X-ray diffraction is less than 0.3370 nm, and (101) diffraction peak and (100) diffraction. The peak intensity ratio (P101 / P100) of the peak is 1.15 or moreAnd not coated with ferromagnetic materialA magnetic field having a magnetic flux density of 2 Tesla or more is applied to a thermally conductive polymer composition containing graphitized carbon fiber and a polymer material, and the heat is applied in a state where the graphitized carbon fiber is oriented in a certain direction. The gist is to solidify the conductive polymer composition.
[0008]
The invention according to claim 2 is the thermally conductive molded article according to claim 1.Manufacturing methodThe graphitized carbon fiber is obtained by sequentially performing spinning, infusibilization and carbonization using mesophase pitch as a raw material and then pulverizing and then graphitizing, and the fiber diameter is 5 to 20 μm. The gist is that the average particle size is 5 to 500 μm.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail.
The thermally conductive molded body in the present embodiment is obtained by molding a thermally conductive polymer composition containing a polymer material and graphitized carbon fiber as a thermally conductive filler into a predetermined shape. The graphitized carbon fibers in the conductive molded body are oriented in a certain direction.
[0011]
First, the graphitized carbon fiber used as the heat conductive filler will be described.
The graphitized carbon fiber used here has an interplanar spacing (d002) between graphite layers of less than 0.3370 nm by the X-ray diffraction method, and the peak intensity ratio of (101) diffraction peak to (100) diffraction peak (P101 / P100) is 1.15 or more. If the interplanar spacing (d002) is 0.3370 nm or more or the peak intensity ratio (P101 / P100) is less than 1.15, the resulting thermally conductive molded body cannot be given sufficient thermal conductivity and is inappropriate. It is. The lower limit of the interplanar spacing (d002) between the graphite layers is 0.3354 nm calculated as a theoretical value, and the upper limit of the peak intensity ratio (P101 / P100) is 3.
[0012]
Here, the X-ray diffraction method measures a diffraction pattern using CuKα as an X-ray source and high-purity silicon as a standard substance. The surface interval (d002) is obtained from the peak position and half-value width of the (002) diffraction pattern. In addition, the peak intensity ratio (P101 / P100) is obtained by drawing a base line from the obtained diffraction diagram, and (101) (2θ≈44.5 degrees), (100) (2θ≈42.5 degrees) from this base line. ) Is measured by measuring the height (P101) and (P100) of each peak and dividing (P101) by (P100).
[0013]
Examples of the raw material for the graphitized carbon fiber include condensed polycyclic hydrocarbon compounds such as naphthalene and phenanthrene, condensed heterocyclic compounds such as petroleum pitch and coal pitch, and the like. Among them, petroleum pitch or coal pitch is preferable, and optically anisotropic pitch, that is, mesophase pitch is particularly preferable. These may be used singly or in appropriate combination of two or more, but the use of mesophase pitch alone, that is, graphitized carbon fiber having a mesophase pitch content of 100% is most preferable.
[0014]
Examples of the graphitized carbon fiber include, but are not particularly limited to, fibrous (including pulverized and cut products in which the fibrous form is maintained), whisker, microcoil, and nanotube.
[0015]
The fiber diameter of the graphitized carbon fiber is preferably 5 to 20 μm, more preferably 5 to 15 μm, and particularly preferably 8 to 12 μm. When the fiber diameter is smaller than 5 μm or larger than 20 μm, the productivity is lowered, which is not preferable.
[0016]
The average particle diameter of the graphitized carbon fiber is preferably 5 to 500 μm, more preferably 15 to 100 μm, and particularly preferably 15 to 45 μm. When the average particle size is less than 5 μm, the contact between the graphitized carbon fibers is reduced and the heat conduction path becomes insufficient, so that the thermal conductivity of the thermally conductive molded body is lowered. On the other hand, if the average particle size is larger than 500 μm, the graphitized carbon fiber becomes bulky, so that it is difficult to fill the polymer material at a high concentration. In addition, the value of the average particle diameter of graphitized carbon fiber can be calculated from the particle size distribution by the laser diffraction method.
[0017]
The thermal conductivity of the graphitized carbon fiber is not particularly limited, but the thermal conductivity in the fiber length direction is preferably 400 W / m · K or more, more preferably 800 W / m · K or more, and 1000 W / m · K or more. Particularly preferred.
[0018]
The graphitized carbon fiber may have a surface modified by oxidation treatment such as electrolytic oxidation or by treatment with a coupling agent or sizing agent. In this case, the wettability and filling property with the polymer material can be improved, and the peel strength at the interface can be improved. Also, by electroless plating method, electrolytic plating method, physical vapor deposition method such as vacuum deposition, sputtering, ion plating, chemical vapor deposition method, painting, dipping, mechanochemical method for mechanically fixing fine particles, etc. A metal or ceramic coated on the surface may be used.
[0019]
Next, the polymer material will be described.
Examples of the polymer material include a thermoplastic resin, a thermoplastic elastomer, a thermosetting resin, and a crosslinked rubber.
[0020]
Examples of the thermoplastic resin include ethylene-α-olefin copolymers such as polyethylene, polypropylene, and ethylene-propylene copolymers, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and ethylene-vinyl acetate copolymers. , Polyvinyl alcohol, polyacetal, fluorine resin (polyvinylidene fluoride, polytetrafluoroethylene, etc.), polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyacrylonitrile, styrene-acrylonitrile copolymer, ABS resin, polyphenylene ether (PPE) ) Resin, modified PPE resin, aliphatic polyamide, aromatic polyamide, polyimide, polyamideimide, polymethacrylic acid (polymer such as polymethylmethacrylate) Acrylic acid ester), polyacrylic acids, polycarbonate, polyphenylene sulfide, polysulfone, polyether sulfone, polyether nitrile, polyether ketone, polyketone, liquid crystal polymer, ionomer and the like.
[0021]
As thermoplastic elastomers, styrene-butadiene copolymers and styrene-isoprene block copolymers and their hydrogenated products, styrene thermoplastic elastomers, olefin thermoplastic elastomers, vinyl chloride thermoplastic elastomers, polyester thermoplastics Examples thereof include elastomers, polyurethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and the like.
[0022]
Thermosetting resins include epoxy resin, polyimide resin, bismaleimide, benzocyclobutene, phenol resin, unsaturated polyester resin, diallyl phthalate, silicone resin, polyurethane, polyimide silicone, thermosetting PPE resin, thermosetting modified PPE Examples thereof include resins.
[0023]
As the crosslinked rubber, natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene-propylene copolymer rubber, chlorinated polyethylene, chlorosulfonated polyethylene, butyl rubber, Halogenated butyl rubber, fluorine rubber, urethane rubber, silicone rubber and the like can be mentioned.
[0024]
Among these polymer materials, from the viewpoint of temperature characteristics such as heat resistance and electrical reliability, silicone rubber, epoxy resin, polyurethane, unsaturated polyester, polyimide, bismaleimide resin, benzocyclobutene resin, fluorine resin, PPE resin And at least one selected from thermoplastic elastomers is preferred. These polymer materials may be used singly or in appropriate combination of two or more, or a polymer alloy composed of two or more polymer materials may be used. Moreover, it does not specifically limit about the crosslinking method of a polymeric material, Well-known crosslinking methods, such as thermosetting, photocuring, and moisture curing, are employable.
[0025]
These polymer materials are appropriately selected and used depending on the application and required performance. For example, fluororesin, thermosetting PPE resin, thermosetting modified PPE resin, and polyolefin resin are preferable for wiring board applications that have a low dielectric constant and dielectric loss tangent and require frequency characteristics in a high frequency region. For adhesive use, adhesive polymers such as epoxy resin, polyimide, and acrylic resin are preferable.
[0026]
Then, the heat conductive polymer composition containing said graphitized carbon fiber and polymer material, and the heat conductive molded object which shape | molded the heat conductive polymer composition in the predetermined shape are demonstrated.
[0027]
The ratio of the polymer material and graphitized carbon fiber contained in the thermally conductive polymer composition is appropriately determined depending on the required performance of the final product, but the graphitized carbon with respect to 100 parts by weight of the polymer material. The fiber is preferably 5 to 500 parts by weight, more preferably 40 to 300 parts by weight. If the blended amount of graphitized carbon fiber is less than 5 parts by weight, the thermal conductivity of the resulting thermally conductive molded body will be small and the heat dissipation characteristics will be degraded. On the other hand, when the amount exceeds 500 parts by weight, the viscosity of the blended composition increases, making it difficult to uniformly disperse the graphitized carbon fiber, and mixing of bubbles is unavoidable, which is not preferable.
[0028]
Furthermore, in addition to the above graphitized carbon fiber, other thermally conductive fillers, flame retardants, softeners, colorants, stabilizers and the like are blended in the thermally conductive polymer composition as necessary. Also good. Other thermally conductive fillers include metals and ceramics, specifically silver, copper, gold, aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum hydroxide, metal Examples thereof include coating resins, graphitized carbon fibers other than the above-mentioned graphitized carbon fibers, non-graphitized carbon fibers, natural graphite, artificial graphite, and mesocarbon microbeads. Examples of the form include a spherical shape, a powder shape, a fiber shape, a needle shape, a scale shape, a whisker shape, a microcoil shape, a single-wall nanotube, and a multi-wall nanotube shape. In applications where electrical insulation is particularly required as the final product, electrical insulating fillers such as aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, and aluminum hydroxide are preferred. In addition, a volatile organic solvent, a low-viscosity softener, or a reactive plasticizer may be added. When these are added, the viscosity of the thermally conductive polymer composition can be reduced, and graphitization can be achieved. The carbon fibers can be easily oriented in a certain direction.
[0029]
In the case of a thermally conductive molded body (thermally conductive sheet) molded into a sheet shape, the hardness is appropriately determined according to the application, but the more flexible the stress relaxation and followability during use, that is, the lower the hardness. Is more advantageous. The specific hardness is preferably 70 or less in Shore A hardness, more preferably 40 or less, and particularly preferably a gel-like silicone rubber or thermoplastic elastomer having an Asker C hardness of 30 or less as a polymer material. Moreover, although thickness is not specifically limited, Preferably it is 50 micrometers-10 mm, More preferably, it is 200 micrometers-5 mm. If it is thinner than 50 μm, it is difficult to produce and handle. If it is thicker than 10 mm, the thermal resistance increases, which is not preferable.
[0030]
Next, the usage method of a heat conductive molded object is demonstrated.
Thermally conductive molded bodies are used as heat radiating members, heat transfer members, or constituent materials for effectively radiating heat generated by electronic components such as semiconductor elements, power supplies, and light sources in electronic devices and the like. . Specifically, it is processed into a sheet shape and used between a heat-generating member such as a semiconductor element and a heat-dissipating member such as a radiator, or a heat sink, semiconductor package component, heat sink, heat spreader, die pad, print They are used after being molded into wiring boards, cooling fan components, heat pipes, casings, and the like.
[0031]
FIG. 1 is a diagram showing an example in which a sheet-like thermally conductive molded body is used as a heat transfer member. In the example shown in FIG. 1A, a thermally conductive molded
[0032]
Next, the manufacturing method of a heat conductive molded object is demonstrated.
Fibrous (pulverized or cut products in which the fibrous form is maintained) using pitch as a raw material is graphitized carbon fiber, which is pulverized or cut after the spinning, infusibilization and carbonization treatments in sequence, and then graphite. Manufactured. The crushing or cutting is not limited to after carbonization, and may be performed after infusibilization or after graphitization, but is most preferably after carbonization. When pulverized or cut after graphitization, it is not preferable because cleavage is likely to occur along the surface of the graphite layer developed in the fiber axis direction, and the ratio of the fracture surface area increases and the thermal conductivity decreases.
[0033]
Examples of the spinning method in the spinning step include a melt spinning method, a melt blowing method, a centrifugal spinning method, a vortex spinning method, and the like. The melt blowing method is preferred from the viewpoint of productivity during spinning and the quality of the graphitized carbon fiber obtained. In the case of the melt blow method, there is also an advantage that the graphite layer surface is easily arranged in parallel to the fiber axis by spinning at a low viscosity of several tens of poises and cooling at a high speed.
[0034]
In the case of the melt blow method, the diameter of the spinning hole is preferably 0.1 to 0.5 mm, and more preferably 0.15 to 0.3 mm. If the diameter of the spinning hole is smaller than 0.1 mm, clogging is likely to occur, and it becomes difficult to manufacture the spinning nozzle, which is not preferable. On the other hand, if it exceeds 0.5 mm, the fiber diameter tends to be as large as 25 μm or more, and the fiber diameter tends to vary, which is not preferable for quality control. The spinning speed is preferably 500 m / min or more from the viewpoint of productivity, more preferably 1500 mm / min or more, and particularly preferably 2000 m / min or more. The spinning temperature may be not lower than the temperature at which the pitch is not lower than the softening point of the raw material pitch, but is usually 300 to 400 ° C, preferably 300 to 380 ° C. From the relationship with the spinning temperature, the softening point of the raw material pitch is preferably 230 to 350 ° C, more preferably 250 to 310 ° C.
[0035]
As an infusibilization method in the infusibilization process, a heat treatment method in an oxidizing gas atmosphere such as nitrogen dioxide or oxygen, a treatment method in an oxidizing aqueous solution such as nitric acid or chromic acid, light, γ-ray, etc. Although the method of superposing | polymerizing is mentioned, The method of heat-processing in the air is preferable from the simplicity. When the method of heat treatment in the air is employed, it is desirable to perform the heat treatment while raising the temperature to about 350 ° C. at an average temperature rise rate of preferably 3 ° C./min or more, more preferably 5 ° C./min or more.
[0036]
The carbonization process in the subsequent carbonization process and the graphitization process in the graphitization process are performed by heat treatment in an inert gas atmosphere. The treatment temperature during the carbonization treatment is preferably 250 to 1500 ° C, more preferably 500 to 900 ° C. The treatment temperature during graphitization is preferably 2500 ° C or higher, more preferably 3000 ° C or higher.
[0037]
For the pulverization or cutting treatment, a pulverizer such as a Victory mill, a jet mill, a high-speed rotary mill, or a cutting machine used for chopped fibers is used. In order to efficiently perform pulverization or cutting, a method of cutting fibers in a direction perpendicular to the fiber axis by rotating a rotor to which blades are attached at high speed is appropriate. The average particle diameter of the graphitized carbon fiber generated by this pulverization or cutting treatment is controlled by adjusting the rotational speed of the rotor, the angle of the blade, and the like. In addition, as a method for pulverizing the fiber, there is a method using a grinding machine such as a ball mill. However, in this method, the pressure in the perpendicular direction of the fiber acts and the occurrence of vertical cracks in the fiber axis direction increases, which is inappropriate. It is.
[0038]
A heat conductive polymer composition is obtained by mixing the graphitized carbon fiber obtained as described above and a polymer material and performing a defoaming operation or the like as necessary. In the mixing, a mixing device or a kneading device such as a blender, a mixer, a roll, or an extruder may be used. And the heat conductive molded object is obtained by shape | molding the obtained heat conductive polymer composition in a defined shape, and when it shape | molds especially in a sheet form, a heat conductive sheet is obtained. Examples of this molding method include a press molding method, an extrusion molding method, an injection molding method, a casting molding method, a blow molding method, a calendar molding method, and the like, and when the heat conductive polymer composition is in a liquid state. , Coating method, printing method, dispenser method, potting method and the like. In the case of molding into a sheet, a compression molding method, a casting molding method, an extrusion molding method, a blade molding method, and a calendar molding method are preferable.
[0039]
Examples of the method for orienting the graphitized carbon fiber in the thermally conductive polymer composition include a method using a flow field or a shear field, a method using a magnetic field, and a method using an electric field. Among them, there is a method of orienting the graphitized carbon fiber parallel to the magnetic field lines by applying a strong magnetic field from the outside to the thermally conductive polymer composition using the relatively large anisotropic magnetic susceptibility of the graphitized carbon fiber. It is preferable because it is efficient and the orientation direction can be arbitrarily set.
[0040]
When producing a thermally conductive molded body using magnetic field orientation, a magnetic field is applied to the thermally conductive polymer composition injected into the mold cavity, and the thermally conductive polymer composition is applied. The thermally conductive polymer composition is solidified in a state where the graphitized carbon fibers contained in the product are oriented in a certain direction.
[0041]
For example, in the case where the graphitized carbon fiber is oriented in the thickness direction (Z-axis direction in FIG. 3) in the plate-like thermally conductive molded
[0042]
In the example shown in FIGS. 4A and 4B, the pair of magnetic field generating means 22 is arranged with the
[0043]
Examples of the magnetic field generating means 22 include permanent magnets and electromagnets. The magnetic flux density of the magnetic field generated by the magnetic field generating means 22 is preferably in the range of 0.05 to 30 Tesla, more preferably 0.5 Tesla or more, and particularly preferably 2 Tesla or more.
[0044]
According to the embodiment described above in detail, the following effects are exhibited.
-Interplanar spacing (d002) between graphite layers by X-ray diffraction of graphitized carbon fibers contained in the thermally conductive compact is less than 0.3370 nm, and the peak intensity ratio (P101 / P100) is 1.15 or more. Thereby, the heat conductivity of a heat conductive molded object can be improved significantly. For this reason, the heat conductive molded object in this embodiment can exhibit the outstanding heat conductivity, and can be used suitably as a heat radiating member in an electronic device etc., a heat-transfer member, or those constituent materials. The reason why the thermal conductivity is greatly improved is not clear, but when graphitized carbon fiber is dispersed in a polymer material, the heat transfer path correlates very strongly with the microstructure of graphitized carbon fiber. It is thought that there is.
[0045]
-Graphitized carbon fiber has very good thermal conductivity in the fiber length direction. Therefore, in a thermally conductive molded body in which graphitized carbon fiber is blended, the thermal conductivity in the orientation direction can be remarkably improved by orienting the graphitized carbon fiber in a certain direction. The heat conductive molded object which has property can be obtained.
[0046]
-By using mesophase pitch as a raw material for graphitized carbon fiber, the thermal conductivity of the obtained thermally conductive molded body can be further improved. In addition, when only mesophase pitch is used as a raw material for graphitized carbon fiber having a mesophase pitch content of 100%, that is, graphitized carbon fiber, spinnability and quality stability can be improved.
[0047]
-The graphitized carbon fiber has a fiber diameter of 5 to 20 μm and an average particle diameter of 5 to 500 μm, so that the polymer material can be filled at a high concentration and the thermal conductivity of the obtained heat conductive molded body can be increased. Can be improved. It is also easy to produce industrially.
[0048]
-By performing each process of spinning, infusibilization, and carbonization in order after crushing or cutting, longitudinal cracking of the fibers can be suppressed. Furthermore, it is easy to obtain graphitized carbon fibers having excellent thermal conductivity because the condensation polymerization reaction and cyclization reaction tend to proceed on the newly exposed surface after pulverization or cutting during the graphitization treatment. There are also advantages.
[0049]
・ Applying a magnetic field from the outside to the thermally conductive polymer composition to orient the graphitized carbon fibers contained in the thermally conductive polymer composition in a certain direction, and in that state the thermally conductive polymer Since the composition is solidified, the graphitized carbon fiber can be efficiently oriented, and the orientation direction can be arbitrarily set.
[0050]
【Example】
Next, the embodiment will be described more specifically with reference to examples and comparative examples.
(Prototype example 1 of graphitized carbon fiber)
Using a petroleum mesophase pitch with optical anisotropy and specific gravity of 1.25 as a raw material, using a die having a spinning hole with a diameter of 0.2 mmφ in a slit with a width of 3 mm, and blowing heated air from the slit, spinning temperature Pitch fibers having an average diameter of 13 μm were produced by pulling the melt pitch at 360 ° C. The spun fibers were collected on a belt to form a mat, which was infusibilized by raising the temperature from room temperature to 300 ° C. at an average temperature rising rate of 6 ° C./min. Subsequently, the infusibilized fiber was slightly carbonized at 700 ° C. and then pulverized by a high-speed rotary mill to obtain a pulverized carbon fiber product. The carbon fiber pulverized product was heated to 2300 ° C. under an argon atmosphere, held at 2300 ° C. for 40 minutes, then heated to 3000 ° C. at a rate of 3 ° C./minute, and further held at 3000 ° C. for 1 hour. Then, the temperature was lowered to produce a graphitized carbon fiber pulverized product. Table 1 shows the measurement results of the density, fiber diameter, average particle diameter, X-ray diffraction parameters, and thermal conductivity in the fiber length direction of this graphitized carbon fiber pulverized product (Prototype Example 1). The thermal conductivity in the longitudinal direction of the fiber was measured using a material that was graphitized under the same conditions without being crushed and in a mat shape.
[0051]
(Prototype example 2 of graphitized carbon fiber)
Using a petroleum mesophase pitch with optical anisotropy and specific gravity of 1.25 as a raw material, using a die having a spinning hole with a diameter of 0.2 mmφ in a slit with a width of 3 mm, and blowing heated air from the slit, spinning temperature Pitch fibers having an average diameter of 15 μm were produced by pulling the melt pitch at 360 ° C. The spun fibers were collected on a belt to form a mat, which was infusibilized by raising the temperature from room temperature to 300 ° C. at an average temperature rising rate of 6 ° C./min. Subsequently, the infusibilized fiber was slightly carbonized at 700 ° C. and then pulverized by a high-speed rotary mill to obtain a pulverized carbon fiber product. This carbon fiber pulverized product was heated to 2300 ° C. in an argon atmosphere, held at 2300 ° C. for 40 minutes, then heated to 3100 ° C. at a rate of 3 ° C./minute, and further held at 3100 ° C. for 1 hour. The temperature was then lowered to produce a graphitized carbon fiber pulverized product. Table 1 shows the results of measurement of the density, fiber diameter, average particle diameter, X-ray diffraction parameters, and thermal conductivity in the fiber length direction of this graphitized carbon fiber pulverized product (Prototype Example 2). The thermal conductivity in the longitudinal direction of the fiber was measured using a material that was graphitized under the same conditions without being crushed and in a mat shape.
[0052]
(Prototype example 3 of graphitized carbon fiber)
An ultra-high modulus pitch graphitized carbon fiber manufactured by Mitsubishi Chemical Corporation was pulverized with a high-speed rotary mill to produce a graphitized carbon fiber pulverized product (Prototype Example 3). Table 1 shows the results of measurement of the density, fiber diameter, average particle diameter, X-ray diffraction parameter, and thermal conductivity in the fiber length direction of the graphitized carbon fiber pulverized product.
[0053]
(Prototype example 4 of graphitized carbon fiber)
An ultra-high modulus pitch graphitized carbon fiber manufactured by Nippon Graphite Fiber Co., Ltd. was pulverized with a high-speed rotary mill to produce a graphitized carbon fiber pulverized product (Prototype Example 4). Table 1 shows the results of measurement of the density, fiber diameter, average particle diameter, X-ray diffraction parameter, and thermal conductivity in the fiber length direction of the graphitized carbon fiber pulverized product.
[0054]
[Table 1]
Example 1
The graphitized carbon fiber of Prototype Example 1 is surface-treated with a silane coupling agent, and 125 parts by weight of the graphitized carbon fiber after the treatment is mixed with 100 parts by weight of unsaturated polyester resin (Nippon Shokubai Epolak Co., Ltd.) and vacuum degassed. A heat conductive polymer composition was prepared by foaming. Subsequently, the thermally conductive polymer composition is injected into a cavity of a predetermined mold, and a magnetic field (magnetic flux density of 10 Tesla) in which the direction of the magnetic field lines matches the thickness direction of the thermally conductive molded body is applied. The graphitized carbon fiber in the conductive polymer composition was sufficiently oriented and then cured by heating to obtain a plate-like thermally conductive molded body having a thickness of 1.5 mm × length 20 mm × width 20 mm.
[0055]
The graphitized carbon fibers in the thermally conductive molded body were aligned in the thickness direction (Z-axis direction). When the thermal conductivity in the thickness direction and in-plane direction of the thermally conductive molded body was measured, it was 11.5 W / m · K and 2.7 W / m · K, respectively.
[0056]
(Example 2)
In Example 1, a magnetic field in which the direction of the magnetic field lines coincided with the in-plane direction (X-axis direction) of the thermally conductive molded body was changed to be applied to the thermally conductive polymer composition in the cavity. Other than that was carried out similarly to Example 1, and produced the plate-shaped heat conductive molded object.
[0057]
The graphitized carbon fibers in the thermally conductive molded body were aligned in the in-plane direction (X-axis direction). When the thermal conductivity in the thickness direction, in-plane direction (X-axis direction) and in-plane direction (Y-axis direction) of the thermally conductive molded body was measured, it was 2.8 W / m · K and 12.6 W / m ·, respectively. K, 2.8 W / m · K.
[0058]
(Example 3)
The graphitized carbon fiber of Prototype Example 2 is surface-treated with a silane coupling agent, and 100 parts by weight of the graphitized carbon fiber after the treatment is mixed with 100 parts by weight of a liquid epoxy resin (TB2280C manufactured by ThreeBond Co., Ltd.) and vacuum degassed. Thus, a heat conductive polymer composition was prepared. Subsequently, the thermally conductive polymer composition is injected into a cavity of a predetermined mold, and a magnetic field (magnetic flux density of 8 Tesla) in which the direction of the magnetic field lines coincides with the thickness direction of the thermally conductive molded body is applied. The graphitized carbon fiber in the conductive polymer composition was sufficiently oriented and then heat-cured to obtain a plate-like thermally conductive molded body having a thickness of 3 mm × length 20 mm × width 20 mm.
[0059]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. The thermal conductivity in the thickness direction and in-plane direction of the thermally conductive molded body was measured and found to be 8.2 W / m · K and 2.5 W / m · K, respectively.
[0060]
Example 4
In Example 3, a magnetic field in which the direction of magnetic field lines coincided with the in-plane direction (X-axis direction) of the thermally conductive molded body was changed to be applied to the thermally conductive polymer composition in the cavity. Other than that was carried out similarly to Example 3, and produced the plate-shaped heat conductive molded object.
[0061]
The graphitized carbon fibers in the thermally conductive molded body were aligned in the in-plane direction (X-axis direction). When the thermal conductivity in the thickness direction, in-plane direction (X-axis direction), and in-plane direction (Y-axis direction) of the thermally conductive molded body was measured, it was 2.6 W / m · K and 9.2 W / m ·, respectively. K, 2.7 W / m · K.
[0062]
(Example 5)
The graphitized carbon fiber of Prototype Example 1 is surface-treated with a silane coupling agent, and 110 parts by weight of the graphitized carbon fiber after the treatment and 60 parts by weight of aluminum oxide powder (AS-20 manufactured by Showa Denko KK) are liquid. A heat conductive polymer composition was prepared by mixing 100 parts by weight of silicone rubber (GESE Silicone Co., Ltd. TSE3070) and vacuum degassing. Subsequently, the thermally conductive polymer composition is injected into a cavity of a predetermined mold, and a magnetic field (magnetic flux density of 12 Tesla) in which the direction of the magnetic field lines coincides with the thickness direction of the thermally conductive molded body is applied. The graphitized carbon fiber in the conductive polymer composition is sufficiently oriented and then cured by heating to form a plate-like thermally conductive molded body (Asker C hardness 17) having a thickness of 0.5 mm × length 20 mm × width 20 mm. Obtained.
[0063]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. It was 11.6 W / m * K and 2.9 W / m * K when the heat conductivity in the thickness direction and in-plane direction of a heat conductive molded object was measured, respectively.
[0064]
(Example 6)
In Example 5, a magnetic field in which the direction of the magnetic lines of force coincided with the in-plane direction (X-axis direction) of the thermally conductive molded body was changed to be applied to the thermally conductive polymer composition in the cavity. Other than that was carried out similarly to Example 5, and produced the plate-shaped heat conductive molded object (Asker C hardness 17).
[0065]
The graphitized carbon fibers in the thermally conductive molded body were aligned in the in-plane direction (X-axis direction). When the thermal conductivity in the thickness direction, the in-plane direction (X-axis direction), and the in-plane direction (Y-axis direction) of the thermally conductive molded body were measured, 2.1 W / m · K, 10. They were 8 W / m · K and 2.5 W / m · K.
[0066]
(Example 7)
To 100 parts by weight of a styrene-based thermoplastic elastomer (Tuftec H1053 manufactured by Asahi Kasei Kogyo Co., Ltd.), 2000 parts by weight of toluene as a solvent is added and dissolved, and 60 parts by weight of graphitized carbon fiber of Prototype Example 1 is mixed therewith to conduct heat. A polymer composition was prepared. Subsequently, the thermally conductive polymer composition is injected into a cavity of a predetermined mold, and a magnetic field (magnetic flux density of 6 Tesla) in which the direction of the magnetic field lines coincides with the height direction of the thermally conductive molded body is applied. After fully orienting the graphitized carbon fibers in the thermally conductive polymer composition, toluene was volatilized and dried by heating to obtain a thermally conductive molded body having a height of 40 mm × length 20 mm × width 20 mm.
[0067]
The graphitized carbon fibers in the thermally conductive molded body were aligned in the height direction. The thermal conductivity in the height direction and in-plane direction of the thermally conductive molded body was measured and found to be 7.4 W / m · K and 2.2 W / m · K, respectively.
[0068]
(Comparative Example 1)
In Example 1, application of a magnetic field when curing the thermally conductive polymer composition was omitted. Other than that was carried out similarly to Example 1, and produced the plate-shaped heat conductive molded object.
[0069]
The graphitized carbon fibers in this thermally conductive molded body were not oriented in a certain direction but were randomly dispersed. The thermal conductivity in the thickness direction and in-plane direction of the thermally conductive molded body was measured and found to be 1.4 W / m · K and 4.2 W / m · K, respectively.
[0070]
(Comparative Example 2)
In Example 3, the graphitized carbon fiber of Prototype Example 4 was used instead of the graphitized carbon fiber of Prototype Example 2. Other than that was carried out similarly to Example 3, and produced the plate-shaped heat conductive molded object.
[0071]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. It was 5.1 W / m * K and 2.3 W / m * K, respectively when the heat conductivity in the thickness direction and in-plane direction of a heat conductive molded object was measured.
[0072]
(Comparative Example 3)
In Example 5, the magnetic flux density of the magnetic field applied when curing the thermally conductive polymer composition was changed to 1.5 Tesla. Other than that was carried out similarly to Example 5, and produced the plate-shaped heat conductive molded object.
[0073]
The graphitized carbon fibers in the thermally conductive molded body were not sufficiently oriented, and the thermal conductivity in the thickness direction and in-plane direction was measured to find 2.7 W / m · K and 3.1 W / m, respectively.・ It was K.
[0074]
(Comparative Example 4)
In Example 5, in place of the graphitized carbon fiber of Prototype Example 1, the graphitized carbon fiber of Prototype Example 3 was changed to be used, and the magnetic flux applied when the thermally conductive polymer composition was cured. The density was changed to 10 Tesla. Other than that was carried out similarly to Example 5, and produced the plate-shaped heat conductive molded object (Asker C hardness 17).
[0075]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. When the thermal conductivity in the thickness direction and in-plane direction of the thermally conductive molded body was measured, they were 8.7 W / m · K and 2.7 W / m · K, respectively.
[0076]
(Comparative Example 5)
In Comparative Example 4, the graphitized carbon fiber of Prototype Example 4 was used instead of the graphitized carbon fiber of Prototype Example 3. Other than that was carried out similarly to the comparative example 4, and produced the plate-shaped heat conductive molded object (Asker C hardness 17).
[0077]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. It was 9.3 W / m * K and 2.8 W / m * K when the heat conductivity in the thickness direction and in-plane direction of a heat conductive molded object was measured, respectively.
[0078]
(Comparative Example 6)
In Example 7, the graphitized carbon fiber of Prototype Example 4 was changed to be used instead of the graphitized carbon fiber of Prototype Example 1. Other than that was carried out similarly to Example 7, and produced the plate-shaped heat conductive molded object.
[0079]
The graphitized carbon fibers in the heat conductive molded body were aligned in the thickness direction. The thermal conductivity in the thickness direction and in-plane direction of the thermally conductive molded body was measured and found to be 5.3 W / m · K and 2.5 W / m · K, respectively.
From the above results, the thermal conductive molded bodies of Examples 1 to 7, Comparative Example 2 and Comparative Examples 4 to 6 have thermal conductivity values in the orientation direction of graphitized carbon fiber, and thermal conductivities in other directions. It was remarkably larger than this value, indicating that the thermal conductivity is anisotropic. Moreover, the value of the thermal conductivity in the orientation direction is that in Examples 1 to 7 using the graphitized carbon fiber of Prototype Example 1 or Prototype Example 2, the graphitized carbon fiber of Prototype Example 3 or Prototype Example 4 is used. It was large as compared with Comparative Example 2 and Comparative Examples 4 to 6 and was shown to have excellent thermal conductivity. Further, in Comparative Example 1 in which no magnetic field was applied and in Comparative Example 3 in which the magnetic field was applied but the magnetic flux density was small, since the graphitized carbon fiber was not oriented, there was no anisotropy in thermal conductivity, The conductivity value was also shown to be small.
[0080]
(Example 8)
A wiring board was produced using the plate-like thermally conductive molded body of Example 3. That is, the thermally conductive molded body of Example 3 was used as a substrate, an electrically insulating epoxy adhesive was applied on the substrate, and a copper foil having a thickness of 35 μm was pressure-bonded by a press, and then the copper foil was etched. As a result, a conductor circuit was formed on the substrate. A transistor (TOS-220, manufactured by Toshiba Corporation) was soldered onto this wiring board, and the opposite surface was energized while being cooled with a cooling fan. The thermal resistance was determined from the temperature difference between the transistor and the wiring board. It was ° C / W.
[0081]
(Comparative Example 5)
A wiring board was produced in the same manner as in Example 8 using the plate-like thermally conductive molded body of Comparative Example 2. A transistor (TOS-220, manufactured by Toshiba Corporation) was soldered onto this wiring board, and the opposite surface was energized while being cooled with a cooling fan. The thermal resistance was determined from the temperature difference between the transistor and the wiring board. It was ° C / W.
[0082]
In addition, the said embodiment can also be changed and comprised as follows.
-You may comprise the printed
[0083]
In addition to the graphitized carbon fiber in the above embodiment, at least one of the following two types of graphitized carbon fiber (A) and (B) is further contained as a heat conductive filler to form a heat conductive polymer. You may change so that a composition may be comprised.
[0084]
(A) Graphitized carbon fiber obtained by sequentially performing spinning, infusibilization and carbonization using mesophase pitch as a raw material, and then pulverizing and then graphitizing.
(B) Graphitized carbon fiber having an average particle size of 500 μm or less and having the following physical properties (1) and (2).
[0085]
(1) Particle size distribution measured by laser diffraction method
10% cumulative diameter (μm): 6-20
50% cumulative diameter (μm): 15-40
90% cumulative diameter (μm): 40-150
(2) Tap density (g / cmThree): 0.6 to 1.5
When the graphitized carbon fiber shown in (A) is included, the thermal conductivity of the thermally conductive molded body can be synergistically improved. Moreover, when the graphitized carbon fiber shown in (B) is included, the thermal conductivity of the thermally conductive molded body can be improved synergistically and the workability can be improved.
[0090]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
According to the first aspect of the present invention, excellent thermal conductivity can be exhibited, and it can be suitably used as a heat radiating member, a heat transfer member, or a component material thereof in an electronic device or the like.A method for producing a thermally conductive molded body is provided..Moreover, the heat conductive molded object which has the outstanding heat conductivity can be manufactured efficiently.
[0091]
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the thermal conductivity can be further improved..
[Brief description of the drawings]
FIGS. 1A to 1D are side views showing an application example of a thermally conductive molded body.
FIG. 2 is a cross-sectional view showing an application example of a thermally conductive molded body.
FIG. 3 is a perspective view showing a square plate-like thermally conductive molded body.
4A and 4B are conceptual diagrams showing a method for manufacturing a thermally conductive molded body.
[Explanation of symbols]
13, 21... Thermally conductive molded body, 17... Substrate as a thermally conductive molded body.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000281703A JP4833398B2 (en) | 2000-09-18 | 2000-09-18 | Method for producing thermally conductive molded body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000281703A JP4833398B2 (en) | 2000-09-18 | 2000-09-18 | Method for producing thermally conductive molded body |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2002088257A JP2002088257A (en) | 2002-03-27 |
JP4833398B2 true JP4833398B2 (en) | 2011-12-07 |
Family
ID=18766320
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2000281703A Expired - Lifetime JP4833398B2 (en) | 2000-09-18 | 2000-09-18 | Method for producing thermally conductive molded body |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP4833398B2 (en) |
Families Citing this family (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003301048A (en) * | 2002-04-10 | 2003-10-21 | Polymatech Co Ltd | Thermally conductive molded product |
JP2004051852A (en) | 2002-07-22 | 2004-02-19 | Polymatech Co Ltd | Thermally conductive polymer molding and its production method |
JP2004140289A (en) * | 2002-10-21 | 2004-05-13 | Funai Electric Co Ltd | Heat radiation structure of electronic component and disk drive device comprising it |
JP2004149722A (en) * | 2002-10-31 | 2004-05-27 | Polymatech Co Ltd | Thermally conductive polymer molded product |
JP4454353B2 (en) * | 2003-05-09 | 2010-04-21 | 昭和電工株式会社 | Linear fine carbon fiber and resin composite using the same |
JP2006113126A (en) * | 2004-10-12 | 2006-04-27 | Sony Corp | Frame body of liquid crystal display panel and liquid crystal display |
JP2006315893A (en) * | 2005-05-11 | 2006-11-24 | Sumitomo Precision Prod Co Ltd | Method for producing carbon nanotube-dispersed composite material |
JP4686274B2 (en) * | 2005-06-30 | 2011-05-25 | ポリマテック株式会社 | Heat dissipation component and manufacturing method thereof |
CN1891780B (en) | 2005-07-01 | 2013-04-24 | 清华大学 | Thermal interface material, and its preparing method |
JP4945097B2 (en) * | 2005-07-05 | 2012-06-06 | Jx日鉱日石エネルギー株式会社 | Totally aromatic liquid crystal polyester resin composition and optical pickup lens holder |
JP2007165357A (en) * | 2005-12-09 | 2007-06-28 | Kyoto Univ | Wiring board |
CN101054467B (en) * | 2006-04-14 | 2010-05-26 | 清华大学 | Carbon nano-tube composite material and preparation method thereof |
JP4950994B2 (en) * | 2006-07-28 | 2012-06-13 | 帝人株式会社 | Thermally conductive adhesive |
KR101449075B1 (en) * | 2006-11-01 | 2014-10-08 | 히타치가세이가부시끼가이샤 | Heat conducting sheet process for producing the same and radiator utilizing the sheet |
JP5080295B2 (en) * | 2007-01-26 | 2012-11-21 | 帝人株式会社 | Heat dissipating mounting board and manufacturing method thereof |
JP2008208490A (en) * | 2007-02-27 | 2008-09-11 | Teijin Ltd | Pitch-based carbon fiber and carbon fiber-reinforced composite material |
JP5334375B2 (en) * | 2007-03-30 | 2013-11-06 | 旭有機材工業株式会社 | Thermosetting resin composition, fiber reinforced molding material and molded body |
US20100314790A1 (en) * | 2009-06-12 | 2010-12-16 | Stansberry Peter G | Highly Oriented Graphite Product |
CN103555085B (en) * | 2013-10-10 | 2015-12-09 | 浙江川科防保材料发展有限公司 | A kind of steel construction special fireproof Lacquer finish functional fluoropolymer coating and preparation technology thereof |
KR102560615B1 (en) * | 2015-08-26 | 2023-07-27 | 덴카 주식회사 | Thermally conductive resin composition |
JP6753745B2 (en) * | 2016-09-12 | 2020-09-09 | デクセリアルズ株式会社 | Heat conduction sheet and semiconductor device |
US10256188B2 (en) | 2016-11-26 | 2019-04-09 | Texas Instruments Incorporated | Interconnect via with grown graphitic material |
US10529641B2 (en) | 2016-11-26 | 2020-01-07 | Texas Instruments Incorporated | Integrated circuit nanoparticle thermal routing structure over interconnect region |
US11004680B2 (en) | 2016-11-26 | 2021-05-11 | Texas Instruments Incorporated | Semiconductor device package thermal conduit |
US10811334B2 (en) | 2016-11-26 | 2020-10-20 | Texas Instruments Incorporated | Integrated circuit nanoparticle thermal routing structure in interconnect region |
US11676880B2 (en) | 2016-11-26 | 2023-06-13 | Texas Instruments Incorporated | High thermal conductivity vias by additive processing |
US10861763B2 (en) | 2016-11-26 | 2020-12-08 | Texas Instruments Incorporated | Thermal routing trench by additive processing |
KR102641305B1 (en) * | 2018-08-30 | 2024-02-28 | 엘지이노텍 주식회사 | Converter |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11302545A (en) * | 1998-02-18 | 1999-11-02 | Nippon Mitsubishi Oil Corp | Silicone rubber composite |
JP2000164215A (en) * | 1998-11-25 | 2000-06-16 | Petoca Ltd | Graphite material for negative electrode of lithium ion secondary battery |
JP2000192337A (en) * | 1998-12-21 | 2000-07-11 | Mitsubishi Chemicals Corp | Graphite carbon fiber and heat-dissipation sheet made thereof |
JP2000195998A (en) * | 1998-12-28 | 2000-07-14 | Polymatech Co Ltd | Heat conductive sheet, its manufacture, and semiconductor device |
-
2000
- 2000-09-18 JP JP2000281703A patent/JP4833398B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JP2002088257A (en) | 2002-03-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4833398B2 (en) | Method for producing thermally conductive molded body | |
US7264869B2 (en) | Thermally conductive molded article and method of making the same | |
EP1199328B1 (en) | Thermally conductive polymer sheet | |
JP4759122B2 (en) | Thermally conductive sheet and thermally conductive grease | |
JP4772239B2 (en) | Graphitized carbon powder and thermally conductive composite composition | |
JP4663153B2 (en) | Thermally conductive composite composition | |
KR100954768B1 (en) | Thermally conductive formed article and method of manufacturing the same | |
JP5015366B2 (en) | Thermally conductive molded body and method for producing the same | |
JP2008208316A (en) | Carbon fiber composite material | |
JP2008069474A (en) | Carbon fiber aggregate suitable for reinforcing material/heat-dissipating material | |
JP2008208316A5 (en) | ||
JP2002097372A (en) | Heat-conductive polymer composition and heat-conductive molding | |
JP2008049607A (en) | Heat-conductive laminate with bonded thin film of electrical insulation | |
JP2009191392A (en) | Pitch-based carbon fiber filer and molded article using the same | |
JP2002146672A (en) | Heat conductive filler, heat conductive adhesive and semiconductor device | |
JP2002088249A (en) | Thermoconductive polymer composition and thermoconductive molded body | |
JP2008248462A (en) | Pitch based carbon fiber filler and molded article using the same | |
JP2009108424A (en) | Thermally conductive filler and molded product using the same | |
JP5015490B2 (en) | Thermally conductive filler and composite molded body using the same | |
JP2002097371A (en) | Heat-conductive polymer composition and heat-conductive molding | |
JP2009108425A (en) | Carbon fiber and composite material using the same | |
JP2002088256A (en) | Thermally conductive polymeric composition and thermally conductive molded product | |
JP2009030215A (en) | Carbon fiber and molded article using the same | |
JP2009108423A (en) | Thermally conductive filler and molded product using the same | |
JP2001081202A (en) | Heat conductive molded article and its preparation and resin substrate for conductive circuit |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070911 |
|
A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100525 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100601 |
|
A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100730 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110607 |
|
A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110729 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110906 |
|
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110922 |
|
R150 | Certificate of patent or registration of utility model |
Ref document number: 4833398 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140930 Year of fee payment: 3 |
|
S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
EXPY | Cancellation because of completion of term |