JP3855487B2 - Polyimide sheet, carbon sheet and process for producing the same - Google Patents
Polyimide sheet, carbon sheet and process for producing the same Download PDFInfo
- Publication number
- JP3855487B2 JP3855487B2 JP25972498A JP25972498A JP3855487B2 JP 3855487 B2 JP3855487 B2 JP 3855487B2 JP 25972498 A JP25972498 A JP 25972498A JP 25972498 A JP25972498 A JP 25972498A JP 3855487 B2 JP3855487 B2 JP 3855487B2
- Authority
- JP
- Japan
- Prior art keywords
- polyimide
- sheet
- carbon
- organic solvent
- heat
- 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 - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Description
【０００１】
【発明の属する技術分野】
この発明は、表面平滑なポリイミドシ−ト、該ポリイミドシ−トを用いて得られる表面平滑なカ−ボンシ−トおよびその製法に関するものである。
さらに詳しくは、この発明は、可溶性ポリイミドの有機溶媒溶液と耐熱性ポリイミド粉末との混合物を金型に流し込んで加熱乾燥して有機溶媒を除去してなる表面平滑なポリイミドシ−ト、該ポリイミドシ−トを焼成し、炭化してなる表面平滑なカ−ボンシ−トおよびその製法に関するものである。
【０００２】
【従来の技術】
最近、燃料電池用セパレ−タ−として、熱硬化性樹脂製の板を不活性雰囲気下に焼成したカ−ボン部材が使用されている。
この燃料電池に使用されるカ−ボン製セパレ−タは、厚板を切削加工して使用されているため、特別な切削加工を必要としないカ−ボンシ−トが求められている。
【０００３】
一方、ポリイミドシ−ト、その焼成品であるカ−ボンシ−トとしては、ポリイミド粉末を高温高圧で圧縮成形して得られるポリイミド成形体およびその焼成品が知られており、例えば、Ｃａｒｂｏｎ、１９７５．Ｖｏｌ．１３．ｐｐ．１４９−１５７にデュポン社のベスペル（厚さ２ｍｍ）を焼成して焼成品を得た例が開示されている。
また、フェノ−ル樹脂などの熱硬化性樹脂を含む紙を焼成する電池用炭素質セパレ−タ−の製造法が特公平６−２２１３５号公報に記載されている。
さらに、芳香族ポリイミドを不活性雰囲気で２０００℃以上、３５００℃以下の温度で熱処理する高電導性ポリイミド熱処理物の製造法が特公平３−５９０８９号公報に記載されている。
しかし、これら公知のポリイミドおよびそれから得られるカ−ボンは、製造に高温高圧を必要とする圧縮成形品あるいは厚さが２５μｍ程度のフィルム状物であり、基板として使用できるカ−ボンシ−トではなかった。
【０００４】
また、特開昭５７−１６３９０９公報および特開昭６０−２０９４４号公報には、芳香族ポリイミドあるいは芳香族ポリアミドを不活性雰囲気中で熱処理して電導体が得られることが記載されている。
しかし、これらの公報にもポリイミドシ−トについて記載されていない。
【０００５】
【発明が解決しようとする課題】
この発明は、厚さが０．５ｍｍ程度以上で表面に特別な切削加工を施すことなく簡単な平滑処理程度で使用可能なカ−ボンシ−トを与えるポリイミドシ−ト、カ−ボンシ−トおよびその製法を提供することである。
【０００６】
【課題を解決するための手段】
この発明は、可溶性ポリイミドの有機溶媒溶液に耐熱性ポリイミド粉末を混合させたスラリ−状のポリイミド混合物を金型に流し込んだ後、加熱乾燥して有機溶媒を除去してなる表面平滑なポリイミドシ−トに関する。
また、この発明は、前記のポリイミドシ−トを焼成し、炭化してなる表面平滑なカ−ボンシ−ト、および前記のポリイミドシ−トを不活性雰囲気下に焼成して炭化する表面平滑なカ−ボンシ−トの製法に関する。
【０００７】
この発明のポリイミドシ−トは、好適には、有機溶媒中で可溶性ポリイミドを与える芳香族テトラカルボン酸、その酸の二無水物またはその酸のエステルと芳香族ジアミンとを重合およびイミド化し、必要であれば有機溶媒を蒸発除去し、得られた固形分濃度が２５−６０重量％程度の可溶性ポリイミドの有機溶媒溶液１００重量部に対し、１０−１００重量部の割合で耐熱性ポリイミド粉末を混合させたスラリ−状のポリイミド混合物を好適には深さ１．２−１０ｍｍ程度の金型に流し込んで、場合によりその表面をバ−コ−タ−などで平滑に処理した後、５０−３５０℃で１−２０時間程度、特に５０−１００℃で１分−１０時間、１００−１５０℃で１分−２０時間の工程を含む多段加熱で徐々に加熱乾燥することによって好適には厚みが１−５ｍｍ程度の表面平滑なシ−トとして得ることができる。
前記のスラリ−状のポリイミド混合物としては、耐熱性ポリイミド粉末を分散させた有機溶媒中で可溶性ポリイミドを与えるテトラカルボン酸成分とジアミン成分とを重合・イミド化させることによっても得ることができる。
【０００８】
この発明における有機溶媒可溶性のポリイミド樹脂を製造するために使用することができるテトラカルボン酸成分としては、例えば２，３，３’，４’−ビフェニルテトラカルボン酸二無水物が好ましく、ピロメリット酸二無水物、３，３’，４，４’−ビフェニルテトラカルボン酸二無水物、３，３’，４，４’−ベンゾフェノンテトラカルボン酸二無水物、２，２−ビス（３，４−カルボキシフェニル）プロパン二無水物、２，３，６，７−ナフタレンテトラカルボン酸二無水物などの他の芳香族テトラカルボン酸二無水物単独あるいは２種類以上を組み合わせて使用してもよい。
【０００９】
この発明における有機溶媒可溶性のポリイミド樹脂を製造するために使用することができるジアミン成分としては、例えば１，３−ビス（４−アミノフェノキシ）ベンゼンが好ましく、４，４’−ジアミノジフェニルエ−テル、４，４’−ジアミノジフェニルスルフィド、４，４’−ジアミノジフェニルメタン、２，２−ビス（４−アミノフェニル）プロパン、２，２−ビス（４−アミノフェノキシメチル）プロパン、１，４−ビス（４−アミノフェノキシ）ベンゼン、４，４’−ビス（４−アミノフェニル）ジフェニルエ−テル、４，４’−ビス（４−アミノフェニル）ジフェニルスルホン、４，４’−ビス（４−アミノフェニル）ジフェニルスルフィド、４，４’−ビス（４−アミノフェノキシ）ジフェニルメタン、４，４’−ビス（４−アミノフェノキシ）ジフェニルエ−テル、４，４’−ビス（４−アミノフェノキシ）ジフェニルメタン、２，２−ビス〔４−（４−アミノフェノキシ）フェニル〕プロパンなどの複数のベンゼン環を有する柔軟な芳香族ジアミンを単独あるいは２種類以上を組み合わせて使用してもよく、その一部を１，４−ジアミノブタン、１，８−ジアミノオクタン、１，１０−ジアミノデカン、１，１２−ジアミノドデカンなどの脂肪族ジアミンの１種類あるいは２種類以上で置き換えて使用してもよい。
【００１０】
この発明における可溶性ポリイミドは、ＩＲ測定法によるイミド化率が８０％程度以上、特に９０％程度以上のものが好ましく、またガラス転移温度が２００−３５０℃程度であるものが好ましい。
【００１１】
前記の有機溶媒としては、Ｎ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミドなどが挙げられる。これらのアミド系溶媒の一部またはほとんどをテトラヒドロフラン、ジエチレングリコ−ルジメチルエ−テル、アセトンなどの含酸素溶媒でおきかえてもよい。
【００１２】
この発明における耐熱性ポリイミドは、有機溶媒に難溶性でＸ線分析によって結晶性が認められる（Ｘ線分析で結晶化度１５％以上であるものが好ましい）芳香族ポリイミドが好ましく、特に４００℃での動的粘弾性が１０4 dyn/cm2 以上、特に１０4 −１０9 dyn/cm2 であるものが好適である。
前記の耐熱性ポリイミドとしては、ピロメリット酸二無水物、ベンゾフェノンテトラカルボン酸二無水物、３，３’，４，４’−ビフェニルテトラカルボン酸二無水物などの芳香族テトラカルボン酸二無水物とｐ−フェニレンジアミン、４，４’−ジアミノジフェニルエ−テルなどの芳香族ジアミンとを有機溶媒中で重合し、得られたポリアミック酸溶液ワニスを支持体に流延し、加熱乾燥したフィルムを機械的に粉砕して得たポリイミド粉末、あるいは前記のポリアミック酸溶液ワニスをさらに加熱乾燥してポリイミド粉末を析出・分離して得たポリイミド粉末が挙げられる。これらは１種類の芳香族テトラカルボン酸成分と１種類の芳香族ジアミンとから得られるポリイミドであってもよく、あるいはランダムあるいはブロックポリイミド、または異種のポリイミド粉末のブレンドであってもよい。
【００１３】
この発明においては、特に、可溶性ポリイミド：耐熱性ポリイミドの割合が重量比で５０：１００−４００：１００となり、混合物中の固形分（ポリイミド）の濃度が２５−９０重量％程度となるように、耐熱性ポリイミド粉末を混合させることが好ましい。
また、可溶性ポリイミドと耐熱性ポリイミドとの混合時に、補強のためにカ−ボンファイバ−チョップを充填することも可能である。
【００１４】
この発明のポリイミドシ−トは、前記の有機溶媒中可溶性ポリイミドと耐熱性ポリイミド粉末とを含むスラリ−状のポリイミド混合物を金型に流し込んで、多段加熱で徐々に加熱乾燥することによって好適には厚みが１−５ｍｍ程度の表面平滑なシ−トとして得ることができる。
この発明のカ−ボンシ−トは、前記のポリイミドシ−トのみを、あるいはポリイミドシ−トに熱圧着性ポリイミドフィルム（またはシ−ト）（好適にはパンチングにより燃料電池などのセパレ−タ−に必要なガス溝を切り抜いたものであって、後の焼成による体積収縮を考慮して３方向の収縮率に見合う設計をしたもの）をポリイミドシ−トの片面あるいは両面に加熱圧着した積層体を炭素板などの支持板で挟んで、窒素ガスあるいはアルゴンガスなどの不活性ガス中、ガラスカ−ボンとなるに必要な温度条件、好適には６５０−１５００℃の温度で１分−１０時間焼成、炭化して厚み０．５−３ｍｍ程度の表面平滑性が良好なシ−ト状物カ−ボンとして得ることができる。
前記の熱圧着性ポリイミドフィルムとしては、それ自体公知のメタ芳香族ジアミン系または１，３−ビス（４−アミノフェノキシ）ベンゼン系熱可塑ポリイミド系フィルムを使用することができる。
【００１５】
この発明のカ−ボンシ−トは、前記の各成分組成からなる有機溶媒可溶性ポリイミドの連続相と高粘弾性の耐熱性ポリイミド粉末とを含むポリイミドシ−トを使用するため表面平滑であり、また焼成温度を変えることによって電気抵抗を幅広い範囲でコントロ−ルすることができ、ガラス状でありガス透過が実質的にない。
このため、この発明の表面平滑性が良好なカ−ボンシ−トは、特に複雑な切削加工を施すことなく、燃料電池用カ−ボン製セパレ−タ−の部材として好適に使用することができる。
【００１６】
【実施例】
以下、この発明の実施例を示す。
以下の記載において、部は重量部を、％は重量％を意味する。
実施例１
攪拌機、窒素導入管および還流装置を備えた反応容器に、Ｎ−メチル−２−ピロリドンを入れ、さらに１，３−ビス（４−アミノフェノキシ）ベンゼン（ＴＰＥ−Ｒ）と２，３，３’，４’−ビフェニルテトラカルボン酸二無水物（ａ−ＢＰＤＡ）とを１００：１００のモル比で添加し、添加終了後１９０℃にて３時間反応を続け、淡黄色粘稠調なポリマ−濃度４７％のポリイミド溶液を得た。
なお、この可溶性ポリイミドはＩＲ法でイミド化率が９５％以上で、ガラス転移温度が約２５０℃で良好な熱圧着性を示す。
【００１７】
このポリイミド溶液に、３，３’，４，４’−ビフェニルテトラカルボン酸二無水物と４，４’−ジアミノジフェニルエ−テルとをＮ，Ｎ−ジメチルアセトアミド中で重合、イミド化して得たポリイミド粉末（ガラス転移温度：２８５℃、Ｘ線分析による結晶化度：約２５％、４００℃での動的粘弾性：２×１０8 ｄｙｎ／ｃｍ2 ）を、可溶性ポリイミド：耐熱性ポリイミド粉末が２：１となる重量割合で混合した（固形分濃度：８２％）。
得られたスラリ−状のポリイミド混合物を深さ１．６ｍｍの金型に流し込み、次の条件で乾燥して、１００ｍｍ×１００ｍｍ×１ｍｍのポリイミドシ−トを得た。
乾燥条件
８０℃×３０分、１００℃×３０分、１２０℃×５時間
得られたシ−トは、機械的強度が大きくて発泡もなく、表面の平滑なポリイミドシ−トであった。
【００１８】
比較例１
Ｎ−メチル−２−ピロリドンで３，３’，４，４’−ビフェニルテトラカルボン酸二無水物と４，４’−ジアミノジフェニルエ−テルとを重合して得られたポリアミック酸溶液（樹脂分２０％）にポリイミド粉末を、ポリアミック酸：耐熱性ポリイミド粉末が２：１となる重量割合で加えたスラリ−状混合物を使用し、次に示す乾燥条件で加熱乾燥した他は他は実施例１と同様に実施した。
乾燥条件
８０℃×３０分、１００℃×３０分、１２０℃×４時間
１５０℃×３０分、２００℃×３分、２５０℃×３分
３５０℃×３分
得られたポリイミドシ−トは、１００ｍｍ×１００ｍｍ×１ｍｍで発泡もなく平面が平滑であったが、脆くカ−ボンシ−トには適用不可であった。
【００１９】
比較例２
２，３，３’，４’−ビフェニルテトラカルボン酸のメチルエステル（ハ−フエステル）と１，３−ビス（４−アミノフェノキシ）ベンゼンとから得られたポリアミック酸溶液（樹脂分４７％）にポリイミド粉末を、ポリアミック酸：耐熱性ポリイミド粉末が２：１の重量割合で加えたスラリ−状混合物を使用し、次に示す乾燥条件で加熱乾燥した他は他は実施例１と同様に実施した。
乾燥条件
８０℃×３０分、１００℃×３０分、１２０℃×４時間
１５０℃×３０分（発泡発生）、２００℃×３分、２５０℃×３分
３５０℃×３分
得られたポリイミドシ−トは１００ｍｍ×１００ｍｍ×１ｍｍで表面に発泡が多数発生しており、カ−ボンシ−トには適用不可であった。
【００２０】
実施例２
実施例１で得られたポリイミドシ−トを次の条件で焼成して炭化し、カ−ボンシ−トを得た。
焼成条件１
ポリイミドシ−トを炭素板（厚さ１０ｍｍ、１ｍｍφの穴付き）で挟んで、窒素ガス中、２５℃／時間で室温から８００℃まで昇温し、８００℃で１時間保持した後、室温まで炉を冷却して炭化した。
焼成条件２
ポリイミドシ−トを炭素板（厚さ１０ｍｍ、１ｍｍφの穴付き）で挟んで、Ａｒガス中、６００℃／時間で室温から１２００℃まで昇温し、１２００℃で２時間保持した後、室温まで炉を冷却して炭化した。
焼成条件３
ポリイミドシ−トを炭素板（厚さ１０ｍｍ、１ｍｍφの穴付き）で挟んで、窒素ガス中、１００℃／時間で室温から１４００℃まで昇温し、１４００℃で５時間保持した後、５０℃／Ｈで３００℃まで降温しその後室温まで炉を冷却して炭化した。
【００２１】
焼成条件１で得られたカ−ボンシ−ト（７８ｍｍ×７８ｍｍ×０．７ｍｍ）は目視観察で表面平滑性が比較的良好で、割って観察したところガラス状であり、曲げ強さが約５００ｋｇ／ｃｍ2 程度であり、電気特性が圧縮成形法によるものと同等で、良好な物性を有するカ−ボンシ−トの特性を示した。
また、焼成条件２、３でも同様な結果が得られた。
【００２２】
【発明の効果】
この発明によれば、表面が平滑で発泡がほとんどないポリイミドシ−トを得ることができる。
また、この発明によれば、表面に特別な切削加工を施すことなく表面が平滑で基板として使用可能なカ−ボンシ−トを得ることができる。
さらに、この発明の方法によれば、高温高圧の圧縮成形を必要とせず、良好な特性を有するカ−ボンシ−トを製造することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface-smoothed polyimide sheet, a surface-smoothed carbon sheet obtained by using the polyimide sheet, and a method for producing the same.
More specifically, the present invention relates to a polyimide sheet having a smooth surface obtained by pouring a mixture of an organic solvent solution of soluble polyimide and a heat-resistant polyimide powder into a mold and drying by heating to remove the organic solvent. The present invention relates to a carbite sheet having a smooth surface obtained by firing and carbonizing a sheet and a method for producing the same.
[0002]
[Prior art]
Recently, a carbon member obtained by firing a thermosetting resin plate in an inert atmosphere has been used as a separator for a fuel cell.
Since the carbon separator used in this fuel cell is used by cutting a thick plate, a carbon sheet that does not require special cutting is required.
[0003]
On the other hand, as a polyimide sheet and a carbon sheet which is a fired product thereof, a polyimide molded body obtained by compression molding polyimide powder at a high temperature and a high pressure and a fired product thereof are known, for example, Carbon, 1975. . Vol. 13. pp. No. 149-157 discloses an example of firing a DuPont Vespel (thickness 2 mm) to obtain a fired product.
Japanese Patent Publication No. 6-22135 discloses a method for producing a carbonaceous separator for batteries in which paper containing a thermosetting resin such as phenol resin is baked.
Further, Japanese Patent Publication No. 3-59089 discloses a process for producing a highly conductive polyimide heat-treated product in which aromatic polyimide is heat-treated at a temperature of 2000 ° C. or higher and 3500 ° C. or lower in an inert atmosphere.
However, these known polyimides and carbons obtained therefrom are compression molded products that require high temperature and high pressure for production, or film-like products having a thickness of about 25 μm, and are not carbon sheets that can be used as substrates. It was.
[0004]
JP-A-57-163909 and JP-A-60-20944 describe that an electrical conductor can be obtained by heat-treating aromatic polyimide or aromatic polyamide in an inert atmosphere.
However, these publications do not describe a polyimide sheet.
[0005]
[Problems to be solved by the invention]
The present invention relates to a polyimide sheet, a carbon sheet, and a carbon sheet which provide a carbon sheet having a thickness of about 0.5 mm or more and which can be used with a simple smoothing process without subjecting the surface to special cutting. It is to provide the manufacturing method.
[0006]
[Means for Solving the Problems]
In this invention, a slurry-like polyimide mixture obtained by mixing a heat-resistant polyimide powder in an organic solvent solution of a soluble polyimide is poured into a mold, and then dried by heating to remove the organic solvent. About
The present invention also provides a smooth carbon sheet obtained by firing and carbonizing the polyimide sheet, and a smooth surface obtained by firing and carbonizing the polyimide sheet in an inert atmosphere. The present invention relates to a method for manufacturing a carbon sheet.
[0007]
The polyimide sheet of the present invention is preferably formed by polymerizing and imidizing an aromatic tetracarboxylic acid, its acid dianhydride or its acid ester, and an aromatic diamine, which give a soluble polyimide in an organic solvent. Then, the organic solvent is removed by evaporation, and the heat-resistant polyimide powder is mixed at a ratio of 10-100 parts by weight with respect to 100 parts by weight of the organic solvent solution of soluble polyimide having a solid content concentration of about 25-60% by weight. The slurry-like polyimide mixture thus prepared is preferably poured into a mold having a depth of about 1.2 to 10 mm, and the surface thereof is optionally treated with a bar coater or the like, and then 50 to 350 ° C. For about 1-20 hours, especially at 50-100 ° C. for 1 minute-10 hours, and at 100-150 ° C. for 1 minute-20 hours, it is preferably thickly dried by heating and drying gradually. There surface smooth sheet of about 1-5 mm - can be obtained as bets.
The slurry-like polyimide mixture can also be obtained by polymerizing and imidizing a tetracarboxylic acid component that gives a soluble polyimide and a diamine component in an organic solvent in which heat-resistant polyimide powder is dispersed.
[0008]
As a tetracarboxylic acid component that can be used for producing an organic solvent-soluble polyimide resin in the present invention, for example, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride is preferable, and pyromellitic acid Dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4 Other aromatic tetracarboxylic dianhydrides such as carboxyphenyl) propane dianhydride and 2,3,6,7-naphthalenetetracarboxylic dianhydride may be used alone or in combination of two or more.
[0009]
As a diamine component that can be used for producing an organic solvent-soluble polyimide resin in the present invention, for example, 1,3-bis (4-aminophenoxy) benzene is preferable, and 4,4′-diaminodiphenyl ether. 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenoxymethyl) propane, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenyl) diphenyl ether, 4,4′-bis (4-aminophenyl) diphenyl sulfone, 4,4′-bis (4-amino) Phenyl) diphenyl sulfide, 4,4′-bis (4-aminophenoxy) diphenylmethane, 4,4′-bis (4-aminophenyl) Flexible aromatics having a plurality of benzene rings such as noxy) diphenyl ether, 4,4′-bis (4-aminophenoxy) diphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane Diamines may be used alone or in combination of two or more, and a part of them is a fat such as 1,4-diaminobutane, 1,8-diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane. One type or two or more types of group diamines may be used.
[0010]
The soluble polyimide in the present invention preferably has an imidization ratio of about 80% or more, particularly about 90% or more by IR measurement, and preferably has a glass transition temperature of about 200 to 350 ° C.
[0011]
Examples of the organic solvent include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide and the like. Some or most of these amide solvents may be replaced with an oxygen-containing solvent such as tetrahydrofuran, diethylene glycol dimethyl ether or acetone.
[0012]
The heat-resistant polyimide in this invention is preferably an aromatic polyimide that is hardly soluble in an organic solvent and has crystallinity observed by X-ray analysis (preferably having a crystallinity of 15% or more by X-ray analysis), particularly at 400 ° C. A material having a dynamic viscoelasticity of 10 4 dyn / cm 2 or more, particularly 10 4 -10 9 dyn / cm 2 is preferred.
Examples of the heat-resistant polyimide include aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. And an aromatic diamine such as p-phenylenediamine and 4,4′-diaminodiphenyl ether are polymerized in an organic solvent, and the resulting polyamic acid solution varnish is cast on a support and heated to dry a film. Examples thereof include polyimide powder obtained by mechanically pulverizing, or polyimide powder obtained by further drying by heating and drying the polyamic acid solution varnish. These may be polyimides obtained from one type of aromatic tetracarboxylic acid component and one type of aromatic diamine, or may be random or block polyimides or blends of different types of polyimide powders.
[0013]
In this invention, in particular, the ratio of soluble polyimide: heat-resistant polyimide is 50: 100-400: 100 in weight ratio, and the concentration of solid content (polyimide) in the mixture is about 25-90% by weight, It is preferable to mix heat-resistant polyimide powder.
It is also possible to fill a carbon fiber chop for reinforcement when mixing the soluble polyimide and the heat-resistant polyimide.
[0014]
The polyimide sheet of the present invention is preferably obtained by pouring a slurry-like polyimide mixture containing the above-mentioned soluble polyimide in an organic solvent and heat-resistant polyimide powder into a mold and gradually heating and drying by multistage heating. It can be obtained as a surface smooth sheet having a thickness of about 1-5 mm.
The carbon sheet of the present invention may be the above polyimide sheet alone, or a thermocompression bonding polyimide film (or sheet) (preferably a separator such as a fuel cell by punching). A gas-fired laminate that is cut out on the one or both sides of a polyimide sheet and cut out the gas grooves necessary for the above and designed to meet the shrinkage in three directions in consideration of volume shrinkage due to subsequent firing. Is sandwiched between a support plate such as a carbon plate and baked at a temperature condition necessary to become a glass carbon in an inert gas such as nitrogen gas or argon gas, preferably at a temperature of 650 to 1500 ° C. for 1 minute to 10 hours. Carbonized, and can be obtained as a sheet-like material carbon having a surface smoothness of about 0.5 to 3 mm.
As said thermocompression bonding polyimide film, a per se known metaaromatic diamine-based or 1,3-bis (4-aminophenoxy) benzene-based thermoplastic polyimide-based film can be used.
[0015]
The carbon sheet of the present invention is smooth because it uses a polyimide sheet containing a continuous phase of organic solvent-soluble polyimide composed of the above-described components and a high-viscoelastic heat-resistant polyimide powder, and By changing the firing temperature, the electric resistance can be controlled in a wide range and is glassy and substantially free of gas permeation.
For this reason, the carbon sheet having good surface smoothness according to the present invention can be suitably used as a member of a separator made of carbon for a fuel cell without particularly complicated cutting. .
[0016]
【Example】
Examples of the present invention will be described below.
In the following description, “part” means “part by weight” and “%” means “% by weight”.
Example 1
Into a reaction vessel equipped with a stirrer, a nitrogen introduction tube and a reflux apparatus, N-methyl-2-pyrrolidone was added, and 1,3-bis (4-aminophenoxy) benzene (TPE-R) and 2,3,3 ′ were added. , 4′-biphenyltetracarboxylic dianhydride (a-BPDA) was added at a molar ratio of 100: 100, and after completion of the addition, the reaction was continued at 190 ° C. for 3 hours to obtain a pale yellow viscous polymer concentration. A 47% polyimide solution was obtained.
This soluble polyimide exhibits good thermocompression bonding at an imidation ratio of 95% or more by an IR method and a glass transition temperature of about 250 ° C.
[0017]
This polyimide solution was obtained by polymerizing and imidizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether in N, N-dimethylacetamide. Polyimide powder (glass transition temperature: 285 ° C., crystallinity by X-ray analysis: about 25%, dynamic viscoelasticity at 400 ° C .: 2 × 10 8 dyn / cm 2 ), soluble polyimide: heat-resistant polyimide powder The mixture was mixed at a weight ratio of 2: 1 (solid content concentration: 82%).
The obtained slurry-like polyimide mixture was poured into a 1.6 mm deep mold and dried under the following conditions to obtain a 100 mm × 100 mm × 1 mm polyimide sheet.
Drying conditions 80 ° C. × 30 minutes, 100 ° C. × 30 minutes, 120 ° C. × 5 hours The sheet obtained was a polyimide sheet with high mechanical strength, no foaming and a smooth surface.
[0018]
Comparative Example 1
A polyamic acid solution (resin component) obtained by polymerizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether with N-methyl-2-pyrrolidone. Example 1 except that a slurry-like mixture in which polyimide powder was added to 20%) at a weight ratio of polyamic acid: heat-resistant polyimide powder to 2: 1 was heat-dried under the following drying conditions. It carried out like.
Drying conditions 80 ° C. × 30 minutes, 100 ° C. × 30 minutes, 120 ° C. × 4 hours 150 ° C. × 30 minutes, 200 ° C. × 3 minutes, 250 ° C. × 3 minutes 350 ° C. × 3 minutes Although it was 100 mm × 100 mm × 1 mm and there was no foaming and the plane was smooth, it was brittle and not applicable to a carbon sheet.
[0019]
Comparative Example 2
To a polyamic acid solution (resin content 47%) obtained from 2,3,3 ′, 4′-biphenyltetracarboxylic acid methyl ester (half ester) and 1,3-bis (4-aminophenoxy) benzene The same procedure as in Example 1 was performed except that a slurry-like mixture in which polyamic acid: heat-resistant polyimide powder was added at a weight ratio of 2: 1 was used and heat-dried under the following drying conditions. .
Drying conditions 80 ° C. × 30 minutes, 100 ° C. × 30 minutes, 120 ° C. × 4 hours 150 ° C. × 30 minutes (foaming), 200 ° C. × 3 minutes, 250 ° C. × 3 minutes 350 ° C. × 3 minutes -The sheet was 100 mm x 100 mm x 1 mm, and a large amount of foam was generated on the surface, which was not applicable to a carbon sheet.
[0020]
Example 2
The polyimide sheet obtained in Example 1 was fired and carbonized under the following conditions to obtain a carbon sheet.
Firing condition 1
A polyimide sheet is sandwiched between carbon plates (thickness 10 mm, with 1 mmφ holes), heated in nitrogen gas from room temperature to 800 ° C. at 25 ° C./hour, held at 800 ° C. for 1 hour, and then to room temperature. The furnace was cooled and carbonized.
Firing condition 2
A polyimide sheet is sandwiched between carbon plates (thickness 10 mm, with holes of 1 mmφ), heated in Ar gas from room temperature to 1200 ° C. at 600 ° C./hour, held at 1200 ° C. for 2 hours, and then to room temperature The furnace was cooled and carbonized.
Firing condition 3
A polyimide sheet is sandwiched between carbon plates (thickness 10 mm, with holes of 1 mmφ), heated in nitrogen gas from room temperature to 1400 ° C. at 100 ° C./hour, held at 1400 ° C. for 5 hours, and then 50 ° C. The temperature was lowered to 300 ° C. at / H, and then the furnace was cooled to room temperature and carbonized.
[0021]
The carbon sheet (78 mm × 78 mm × 0.7 mm) obtained under firing condition 1 has a relatively good surface smoothness by visual observation, and when observed by splitting, it is glassy and has a bending strength of about 500 kg. The characteristic of the carbon sheet having a good physical property is shown, which is about / cm 2 , the electric characteristics are the same as those obtained by the compression molding method.
Similar results were obtained under firing conditions 2 and 3.
[0022]
【The invention's effect】
According to this invention, a polyimide sheet having a smooth surface and almost no foaming can be obtained.
In addition, according to the present invention, it is possible to obtain a carbon sheet that has a smooth surface and can be used as a substrate without subjecting the surface to special cutting.
Furthermore, according to the method of the present invention, a carbon sheet having good characteristics can be produced without requiring high temperature / high pressure compression molding.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25972498A JP3855487B2 (en) | 1998-09-14 | 1998-09-14 | Polyimide sheet, carbon sheet and process for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25972498A JP3855487B2 (en) | 1998-09-14 | 1998-09-14 | Polyimide sheet, carbon sheet and process for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000084958A JP2000084958A (en) | 2000-03-28 |
| JP3855487B2 true JP3855487B2 (en) | 2006-12-13 |
Family
ID=17338077
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25972498A Expired - Fee Related JP3855487B2 (en) | 1998-09-14 | 1998-09-14 | Polyimide sheet, carbon sheet and process for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3855487B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4245522B2 (en) * | 2003-07-07 | 2009-03-25 | 東洋炭素株式会社 | Carbonized product and production method thereof |
| KR100726961B1 (en) * | 2005-07-27 | 2007-06-14 | 삼원에프에이 (주) | Method for makeing a call of condolence remotely |
| JP2008254937A (en) * | 2007-03-30 | 2008-10-23 | Ube Ind Ltd | Manufacturing method for obtaining carbonaceous film having shape as one's objective |
| JP2008135399A (en) * | 2008-01-07 | 2008-06-12 | Ube Ind Ltd | Electrolyte membrane-electrode assembly, fuel cell, and method of manufacturing electrolyte membrane-electrode assembly |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3715891A1 (en) * | 1987-05-13 | 1988-11-24 | Bayer Ag | SPECIAL POLYAMIDES AS FILMS AND COATINGS |
| JPH0776084B2 (en) * | 1989-11-21 | 1995-08-16 | 東海カーボン株式会社 | Method for producing high density glassy carbon film |
| JP2951484B2 (en) * | 1991-08-28 | 1999-09-20 | ユニチカ株式会社 | Powder and granules of polyimide precursor, mixture thereof and production method thereof |
| JPH09171826A (en) * | 1995-12-19 | 1997-06-30 | Tdk Corp | Lithium secondary battery |
-
1998
- 1998-09-14 JP JP25972498A patent/JP3855487B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000084958A (en) | 2000-03-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3551846B2 (en) | Terminal-modified imide oligomer and cured product thereof | |
| TWI714971B (en) | Polyimide film, manufacturing method thereof, graphite sheet prepared by using the same and electronic device | |
| CN107108926B (en) | Method for producing polyimide film using porous particles and low dielectric constant polyimide film | |
| KR102153509B1 (en) | Ultra-Thin Polyimide Film with Improved Dimensional Stability and Method for Preparing the Same | |
| KR20080034876A (en) | Metal-coated polyimide film | |
| KR102171061B1 (en) | Polyimide Film with Improved Surface Property and Method for Preparing the Same | |
| US7811660B2 (en) | Polyimide film having high adhesiveness and method for producing same | |
| TW202118816A (en) | Polyimide film, method of producing the same, and multilayer film, flexible metal foil laminate and electronic component containing the same | |
| US20020120091A1 (en) | Poly amic acid system for polyimides | |
| JP3855487B2 (en) | Polyimide sheet, carbon sheet and process for producing the same | |
| KR102162628B1 (en) | Flexible Metal Foil Clad Laminate | |
| JP7442613B2 (en) | Polyamic acid composition, method for producing polyamic acid composition, and polyimide containing the same | |
| KR102172562B1 (en) | Graphite sheet manufactured from polyimide film having superior orientation and manufacturing method for the same | |
| KR102153508B1 (en) | Polyimide Film Comprising Crystalline Polyimide Resin and Thermal Conductive Filler and Method for Preparing The Same | |
| CN109748269A (en) | A kind of composite graphite preparation of sections method | |
| KR102172561B1 (en) | Manufacturing Method of Polyimide Film with Superior Orientation, Polyimide Film Prepared Thereby and Graphite Sheet Prepared by Using the Same | |
| KR102125686B1 (en) | Polyamic acid composition and method for preparing the same | |
| KR102013535B1 (en) | Method for Preparing Polyimide Precursor Composition With Improved Storage Stability and Viscosity Stability, and Polyimide Precursor Composition Prepared by Using the Same | |
| JP2962784B2 (en) | Polyimide cured resin composite and manufacturing method thereof | |
| JP3528236B2 (en) | Roughened polyimide film and method for producing the same | |
| KR102652586B1 (en) | Polyimide film with improved mechanical strength and thermal resistance and manufacturing method thereof | |
| KR102644735B1 (en) | Aqueous polyamic acid composition | |
| KR102621023B1 (en) | Aqueous polyamic acid composition | |
| KR102644736B1 (en) | Aqueous polyamic acid composition | |
| KR102644737B1 (en) | Aqueous polyamic acid composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040304 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050902 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060411 |
|
| 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: 20060822 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20060904 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100922 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100922 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110922 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110922 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120922 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120922 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120922 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130922 Year of fee payment: 7 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |