JP4454115B2 - Seamless belt - Google Patents

Description

(Ｒ₀は炭素間結合又は２価の炭化水素基を示し、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄はそれぞれ水素、アルキル基又はアリール基を示す)で表される。具体例としては、２，２′‐ビス(２‐オキサゾリン)、２，２′‐ビス(５‐メチル‐２‐オキサゾリン)、２，２′‐ビス(５，５′‐ジメチル‐２‐オキサゾリン)、２，２′‐ビス(４，４，４′，４′‐テトラメチル‐２‐オキサゾリン)、１，２‐ビス(２‐オキサゾリン‐２‐イル)エタン、１，４‐ビス(２‐オキサゾリン‐２‐イル)ブタン、１，６‐ビス(２‐オキサゾリン‐２‐イル)ヘキサン、１，８‐ビス(２‐オキサゾリン‐２‐イル)オクタン、１，４‐ビス(２‐オキサゾリン‐２‐イル)シクロヘキサン、１，２‐ビス(２‐オキサゾリン‐２‐イル)ベンゼン、１，３‐ビス(２‐オキサゾリン‐２‐イル)ベンゼン、１，４‐ビス(２‐オキサゾリン‐２‐イル)ベンゼン、１，２‐ビス(５‐メチル‐２‐オキサゾリン‐２‐イル)ベンゼン、１，３‐ビス(５‐メチル‐２‐オキサゾリン‐２‐イル)ベンゼン、１，４‐ビス(５‐メチル‐２‐オキサゾリン‐２‐イル)ベンゼン、１，４‐ビス(４，４′‐ジメチル‐２‐オキサゾリン‐２‐イル)ベンゼン等があげられる。このうち、特に扱いやすい融点を有する１，３‐ビス(２‐オキサゾリン‐２‐イル)ベンゼンの使用が好ましい。これらは単独あるいは併用して用いてもかまわない。
【０００９】
多価芳香族ポリアミンは、分子内に少なくとも２つのアミノ基を有していれば良く、単環式又は多環式の化合物であっても良い。この多価芳香族ポリアミンの具体例としては、例えば４，４′‐ジアミノビフェニル、３，３′‐ジメトキシ‐４，４′‐ジアミノビフェニル、４，４′‐ジアミノトリフェニルメタン、３，３′‐ジメチル‐４，４′‐ジアミノビフェニル、２，２′，５，５′‐テトラクロロ‐４，４′‐ジアミノビフェニル、４，４′‐メチレンビスアニリン、４，４′‐メチレンビス(２‐クロロアニリン)、２，２′‐ビス〔４‐(４‐アミノフェノキシ)フェニル〕プロパン、１，３‐ビス(４‐アミノフェノキシ)ベンゼン、１，３‐ビス(３‐アミノフェノキシ)ベンゼン、３，４′‐ジアミノジフェニルエーテル、４，４′‐ジアミノジフェニルスルフィド、４，４′‐ビス(アミノフェニル)アミン、４，４′‐〔１，３‐フェニレンビス(１‐メチルエチリデン)〕ビスアニリン、４，４′‐〔１，４‐フェニレンビス(１‐メチルエチリデン)〕ビスアニリン等があげられる。これら多価芳香族ポリアミンの中では、入手の容易性から４，４′‐メチレンビスアニリン、２，２′‐ビス〔４‐(４‐アミノフェノキシ)フェニル〕プロパン等が好ましい。
【００１０】
可撓性の観点からは、４，４′‐ジアミノビフェニル、３，４′‐ジアミノジフェニルエーテル、４，４′‐ジアミノジフェニルスルフィド等が好ましく、４，４′‐メチレンビス(２‐クロロアニリン)、３，３′，５，５′‐テトラメチル‐４，４′‐ジアミノジフェニルメタン、３，３′，５，５′‐テトラエチル‐４，４′‐ジアミノジフェニルメタン、３，３′‐ジメチル‐５，５′‐ジエチル‐４，４′‐ジアミノジフェニルメタン等は溶融粘度を下げる効果があり、特に好ましい。これら多価芳香族ポリアミンは、単独あるいは２種以上の混合物として用いても良い。
【００１１】
ジカルボン酸の具体例としては、例えばマロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、ドデカン二酸、エイコサン二酸、マレイン酸、フマル酸、イタコン酸、フタル酸、イソフタル酸、テレフタル酸、ナフタレンジカルボン酸、両末端がカルボキシル化されたポリエーテルグリコール、ポリエステルグリコール、ポリカーボネートオリゴマー、ＮＢＲオリゴマー等があげられる。ジカルボン酸の中では、アジピン酸、アゼライン酸、テレフタル酸等が好ましい。これらのジカルボン酸は、炭素数が大きいほど伸びが増し、可撓性を示す。さらに、多価芳香族ポリアミンと反応させる前に、予め過剰のビス(２‐オキサゾリン)化合物と反応させ、プレポリマー化すると架橋点間の距離をより大きくすることができ、可撓性を調整することが可能になる。これらジカルボン酸も、単独あるいは２種以上の混合物として用いることができる。
【００１２】
ビス(２‐オキサゾリン)化合物(ａ)と、多価芳香族ポリアミン(ｂ)と、ジカルボン酸(ｃ)との混合モル比はビス(２‐オキサゾリン)のオキサゾリン基が開環してアミンあるいはカルボン酸と反応するものであるから、(ａ)／((ｂ)＋(ｃ))は架橋密度に影響するものであり、１より大きくなければならず、これより小さいと十分な反応生成物はできない。(ａ)／((ｂ)＋(ｃ))が２．０以上大きくてもあまり物性上影響はないが、大き過ぎるとピークを超えて物性の低下する傾向がみられる。(ａ)、(ｂ)、(ｃ)の３成分の混合物の溶融粘度は、その比が大きいほど低粘度になるが、中間転写ベルト等のベルトとして機能するには十分なモジュラスと伸びとが必要であり、１．０＜(ａ)／((ｂ)＋(ｃ))＜＝３．０が望ましく、１．１＜(ａ)／((ｂ)＋(ｃ))＜＝２．０がより望ましい。
この他、４，４′‐チオビスベンゼンチオール等のジチオールは、ビス(２‐オキサゾリン)化合物との反応性も高く、ジカルボン酸と同様に使用することができる。
【００１３】
上記化合物のための反応触媒としては、カチオン触媒が用いられる。具体例としては、強酸、スルホン酸エステル、硫酸エステル、ルイス酸、脂肪族、又は脂環族炭素、例えばアルキル炭素やアルキレン炭素に結合したハロゲン原子を少なくとも１つ有するハロゲン化物等があげられる。触媒は、単独で使用しても良いし、併用しても良い。
【００１４】
加工に必要な粘度は加工法によるが、一般的に行われる回転成形では、加熱溶融や、必要ならばトルエン、キシレン等の芳香族系、アセトン、ＭＥＫ、ＭＩＢＫ等のケトン系、酢酸エチル、酢酸ブチル、酢酸カルビトール等のエステル系、モノグライム、ジグライム、トリグライム等のエーテル系、ジメチルアセトアミド、ジメチルホルムアミド、ｎ‐メチルピロリドン等の窒素系の単一あるいは混合溶剤に溶かした溶液が用いられる。この溶液の粘度は、通常３０〜３，０００ｃｐ程度である。
【００１５】
静電付着等に必要な１０⁸〜１０¹⁴(Ω・ｃｍ)の半導電性を付与するカーボンブラックは、ファーネスブラック、酸化ファーネスブラック、チャンネルブラックなどから選択されるが、それらの表面には不飽和結合、あるいはカルボキシル基や水酸基等の活性水素があり、絶縁性樹脂の一部と反応し、機械的、熱的振動、又は電流の影響に伴うカーボンブラックの接触状態の変化が抑制される。また、絶縁性樹脂が直接カーボンブラックと反応しなくても、カーボンブラック表面の不飽和結合あるいは活性水素に結合する化合物と反応すれば、同様の効果が得られる。
しかしながら、過度に反応すると、成形前の樹脂溶液の粘度が上昇し、不安定化したり、抵抗値が高くなったり、あるいは成形前の物性が劣化することから、予めカーボンブラック表面をエステル化、アルキル化、シリル化、又はアミド化等し、反応性を低下させることが必要である。
【００１６】
この前処理を説明すると、一次粒子径が５〜３０ｎｍで揮発分２〜２０％のチャンネルブラックあるいは酸化処理されたファーネスブラック等と、アルコール類とを塩酸等の触媒を使用して反応させ、エステルを生成する。または、硫酸ジメチル等を使用してのメチル化、Ｎ‐ビニルカルバゾールやメチルスチレン等のビニルモノマーをカチオングラフトすること等により、アルキル化する。また、メチルクロロシラン、ヘキサメチルジシラザン等のシリカ剤を噴霧、加熱して前処理カーボンブラックを得ることができる。さらにまた、イソシアネートやオキサゾリン化合物を溶媒中で還流させ、前処理カーボンブラックを得ることもできる。
【００１７】
イソシアネート及びオキサゾリン化合物は、カーボンブラック表面の不揮発分の活性水素に対し、効率良く反応し、活性水素を有するアミド結合、ウレタン結合を生成させるので、絶縁性樹脂の一部が反応する。また、ファーネスブラックは反応性基を有していないが、ルイス酸触媒下でアシルクロリドを反応させたり、アゾ化合物、パーオキサイド化合物の分解反応物をラジカル反応させて前処理カーボンブラックを得ることができる。
【００１８】
反応させるモノマーは、分子量が大きいほど、あるいは反応させる量が多いほどカーボンブラックの反応性を低下させ、絶縁性樹脂による適度な補足ができる。但し、過剰だと補足が不充分となり、カーボンブラックが動いて再配列するので注意が必要である。カーボンブラックの前処理の状態は、カーボンブラックのｐＨを測定するか、アルカリ滴定を行い、定量化することができる。
【００１９】
この他、シリカ、アルミナ、酸化チタン、水酸化アルミニウム、炭酸カルシウム、炭酸マグネシウム、タルク、クレー等の充填材も合成樹脂成形の分野で使用されている任意のものを用いることができる。但し、増粘をもたらすもの等は避ける必要がある。また、通常の合成樹脂成形の分野で使用されている安定剤、酸化防止剤、内部離型剤、顔料、分散剤、難燃剤等の任意の添加剤をも用いることが可能である。
【００２０】
次に、本発明に係るシームレスベルトの製造方法について説明する。先ず、シームレスベルト用材料を調整するが、この場合には、加工時間と温度から適正な濃度、粘度、溶剤沸点を選択する。こうして加工時間や温度等を選択したら、絶縁性樹脂(少なくとも一部は熱硬化性樹脂)に必要な溶剤を加え、樹脂原液を得る。
【００２１】
次いで、カーボンブラックを、通常の分散装置、例えば溶液状態あるいは乾燥状態でポットミル、サイクロイドミル、アッペクスミル、ダイノールミル、アトライターミル、ジェットミル等で十分解碎し、一次凝集体にする。一次凝集体を得たら、これを湿式あるいは乾式でモノマーと反応させ、必要ならば洗浄・乾燥して前処理カーボンブラックを調製し、これを樹脂原液に分散混合して半導電性の溶液あるいは溶融スラリーを得る。
【００２２】
次いで、スラリーに硬化剤や触媒を添加し、予め回転させている管状の金型に注入する。この際、スラリーの溶融粘度は５０ポイズ以下が良い。これは、５０ポイズを超えると、均一な膜厚を得るのが困難になるからである。また、遠心成形用の金型は、約５００〜３，０００ｒｐｍで回転させ、１２０〜２００℃に加熱しておく。溶剤を揮発するための乾燥、反応時間は、４５〜２００分ほど必要であるが、熱硬化性樹脂単独の場合には、加熱時間が短く、５〜３０分ほどで良い。こうして所定の時間が経過し、その後、金型を室温まで冷却すれば、５０〜２００μｍの厚さを有するエンドレスで可撓性のシームレスベルトを作製することができる。
【００２３】
ところで、シームレスベルトの抵抗値は、印刷回数が増すにしたがい、付着や剥離用の印加電圧により、表面抵抗値が徐々に低下する。そこで、トナーや紙等の付着と剥離が確実に行われることを見越して、初期においては、体積抵抗値よりも約２桁以上高い表面抵抗値が望まれ、数万から数十万回の印刷後でも表面抵抗の減少が２桁以下程度であることが実用的な限界となっている。この実際の経時変化を実機で確認するのは時間がかかるが、促進試験によれば把握することができる。
【００２４】
すなわち、シームレスベルトを２枚の導電性の弾性電極により印刷用紙と共に挟持し、シームレスベルトに０．０２ｍＡ／ｃｍ²以下のパルス電流を耐用印刷回数の５〜１０倍のパルス数をかければ、表面抵抗値の変化を確認することができる。この時の印加電圧は、シームレスベルトの抵抗や弾性電極の電極面積で変化するが、おおよそ数百〜数千ボルトである。抵抗の測定には、任意の測定器を使用することができるが、三菱化学株式会社製のハイレスター〔商品名〕等が一般に使用される。
【００２５】
【実施例】
以下、本発明に係るシームレスベルトの実施例を比較例と共に説明する。
実施例１の調整
先ず、ポリエーテルサルフォン〔住友化学株式会社製 商品名４８００Ｇ〕８００ｇと、エポキシ当量４７５でビスフェノールＡタイプのエポキシ樹脂２００ｇと、ポリアミド系硬化剤１００ｇ〔旭電化株式会社製 商品名ＥＨ‐３３３〕とをＮ‐メチルピロリドンとトルエン〔混合ｗｔ比９：１〕に溶解し、固形分１５％の樹脂溶液を調製した。この樹脂溶液の粘度は６ポイズであった。
【００２６】
樹脂溶液を調製したら、ファーネスブラック〔三菱化学株式会社製 商品名＃２４００〕を３規定の硝酸中で６０℃、１時間反応させ、濾過・水洗し、乾燥させたカーボンブラックを樹脂溶液の固形分に対して１．７ｗｔ％配合し、ビーズミルで１６時間分散混合してスラリーを得た。こうしてスラリーを得たら、このスラリーを１，０００ｒｐｍで回転している金型に注入し、５０分間乾燥硬化させ、その後、金型を常温まで冷却して試料Ａを作製した。金型は、内周面がクロムメッキされたφ２００ｍｍの鋼管とし、１３５℃で加熱した。スラリーをさらに１３５℃、５０分間還流操作し、上記と同様に試料Ｂを作製し、絶縁性樹脂との反応確認用とした。
【００２７】
実施例２の調整
先ず、１，３‐ビス(２‐オキサゾリン‐２‐イル)ベンゼン２３８ｇ(１．１モル)と、４，４′‐〔１，４‐フェニレンビス(１‐メチルエチリデン)〕ビスアニリン２７５ｇ(０．８モル)と、４，４′‐チオビスベンゼンチオール５０ｇ(０．２モル)とを秤量し、１５０℃のオイルバス中に容器に取り、ミキサで攪拌した。こうしてミキサで攪拌したところ、約１５分後に全て溶融したので、さらに２時間攪拌し、熱硬化性樹脂原液を調製した。この熱硬化性樹脂原液を１２０℃まで冷却し、ポリカーボネート〔帝人化成株式会社製 商品名Ｋ１２８５〕のジメチルフォルムアミド溶液２８０ｇと混合し、１０時間かけて溶剤を揮発し、樹脂原液を得た。この樹脂原液の粘度は１２０℃で１２ポイズであった。
【００２８】
次いで、樹脂原液にチャンネルブラック〔デグサ株式会社製 商品名１５０Ｔ〕８ｗｔ％のフェニルイソシアネートを酢酸エチル溶液中で８０°、１時間反応させた。乾燥させた前処理カーボンブラックを樹脂原液の固形分に対して４．８ｗｔ配合し、高速攪拌機で１６時間分散混合した。こうしてスラリーを得たら、このスラリーに臭化オクチルを２ｐｈｒ添加混合するとともに、スラリーを２，０００ｒｐｍで回転している金型に直ちに注入し、１５分間乾燥硬化させ、その後、金型を常温まで冷却して試料Ａを作製した。金型は、内周面がクロムメッキされたφ２００ｍｍの鋼管とし、１４５℃で加熱した。スラリーをさらに１４５℃、１５分間加熱操作し、上記と同様に試料Ｂを作製し、絶縁性樹脂との反応確認用とした。
【００２９】
実施例３の調整
先ず、１，３‐ビス(２‐オキサゾリン‐２‐イル)ベンゼン３０３ｇ(１．４モル)と、４，４′‐メチレンビスアニリン１９８ｇ(１．０モル)とを秤量し、１５０℃のオイルバス中に容器に取り、ミキサで攪拌した。こうしてミキサで攪拌したところ、約１５分後に全て溶融したので、さらに２時間攪拌し、熱硬化性樹脂原液を調製した。この熱硬化性樹脂原液の粘度は１２０℃で２ポイズであった。この熱硬化性樹脂原液に酸化チャンネルブラック〔デグサ株式会社製 商品名＃５５０〕８ｗｔ％のフェニルオキサゾリンを酢酸エチル溶液中で８０°、３時間反応させた。
【００３０】
乾燥させた前処理カーボンブラックを樹脂原液の固形分に対して４．８ｗｔ配合し、高速攪拌機で１６時間分散混合した。こうしてスラリーを得たら、このスラリーに臭化オクチルを２ｐｈｒ添加混合するとともに、スラリーを２，０００ｒｐｍで回転している金型に直ちに注入し、１０分間乾燥硬化させ、その後、金型を常温まで冷却して試料Ａを作製した。金型は、内周面がクロムメッキされたφ２００ｍｍの鋼管とし、１４０℃で加熱した。スラリーをさらに１４５℃、５０分間加熱操作し、上記と同様に試料Ｂを作製し、絶縁性樹脂との反応確認用とした。
【００３１】
比較例１の調整
カーボンブラックが酸化処理されていないことを除き、実施例１と同様にして試料Ａ、試料Ｂを作製した。
比較例２の調整
ポリアミドイミドワニス〔東洋紡績株式会社製 商品名ＮＸ１００〕(固形分１５％、溶剤、N‐メチルピロリドン)に、実施例２で示す前処理カーボンブラックを樹脂溶液の固形分に対し２．１ｗｔ％配合し、ビーズミルで１６時間分散混合し、スラリーを得た。得られたスラリーを実施例２と同様に処理し、試料Ａ、試料Ｂを作製した。
【００３２】
反応確認
試料Ａ、試料Ｂの体積抵抗をハイレスターで測定した。この測定に際しては、５００Ｖを印加し、測定５点の平均値で算出した。
促進試験
試料Ａ、試料Ｂの体積抵抗と表面抵抗とをハイレスターで測定した。この測定に際しては、５００Ｖを印加し、測定５点の平均値で算出した。続いて、試料Ａに印刷用紙を載せ、厚さ１ｍｍの導電性シリコーンゴム電極(比抵抗５Ω・ｃｍ)で挟み、２０ｇｆ／ｃｍ²になるよう錘を載せた。こうして錘を載せたら、導電性シリコーンゴム電極に０．０１５ｍＡ／ｃｍ²の電流が流れるように商業波の高電圧を一定の電圧で印加し、１６時間印加後、表面抵抗を再度測定した。
【００３３】
【表１】

【００３４】
【発明の効果】
以上のように本発明によれば、絶縁性樹脂の一部がカーボンブラックと反応するので、印刷回数の増加にしたがいカーボンブラックの再配列を起こす微小な動きを規制することが可能になる。そしてこれを通じ、印刷のかすれ、汚れ、位置ずれ等の印刷の不具合発生を抑制することができるとともに、部品モジュールの長期使用が期待できるという産業上の利用価値のきわめて高いシームレスベルトを提供することができるという効果がある。
また、絶縁性樹脂が、ビス(２‐オキサゾリン)化合物と、多価芳香族ポリアミンと、ジカルボン酸との少なくとも一方の反応生成物なので、優れた強度、耐久性、加工性を得ることができる。また、機械的、熱的振動、又は電流の影響に伴うカーボンブラックの接触状態の変化を抑制することができる。 [0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductive seamless belt which can be used for an electrophotographic copying machine, a laser printer, a facsimile machine, or an OA device combining these, and can be transported and peeled off by electrostatically attaching toner or paper. It is.
[0002]
[Prior art]
A conventional seamless belt used as an intermediate transfer belt or the like in an electrophotographic copying machine or the like is not shown, but from the viewpoint of image quality and durability, polyimide resin, polyamideimide resin, polycarbonate resin, polyethersulfone resin, It is molded using a synthetic resin such as polyarylate resin or polyphenyl ether resin. Specifically, 0.1 to 20 wt% of carbon black is dispersed and mixed, and is formed by rotational molding or the like to obtain a uniform film thickness, and is set to a surface resistance and volume resistance suitable for the equipment used. .
[0003]
[Problems to be solved by the invention]
By the way, from the viewpoint of increasing the speed of devices in recent years, diversifying the charging characteristics of toner by increasing the number of colors, improving the printing quality, and the like, it is necessary to quickly and reliably attach or remove toner or paper. Therefore, the surface resistance of the seamless belt is required to be higher than the volume resistance.
However, when the number of times of printing increases, the surface resistance of the seamless belt gradually decreases due to the high voltage applied for adhesion and separation, and adhesion and separation become uncertain. As a result, printing defects such as faint printing, smudges, and misregistration occur, and finally an expensive component module must be replaced.
[0004]
The present invention has been made in view of the above, and an object of the present invention is to provide a seamless belt that can suppress and prevent printing defects such as fading, smudges, and misregistration, and extend the life of a component module.
[0005]
[Means for Solving the Problems]
As a result of repeated investigations on the above problems, the present inventors have conducted a minute current by applying a high voltage, and as a result of rearrangement of carbon black along with it, a conductive path is formed and the surface resistance value is reduced. I found it to decline. In response, the inventors have found that if the movement of carbon black in the insulating resin is restricted, the decrease in surface resistance can be suppressed, and the present invention has been completed.
That is, in order to solve the above-described problems in the present invention, a semi-conductive seamless belt in which carbon black is dispersed and mixed in an insulating resin and centrifugally molded,
The insulating resin comprises at least one reaction product of a bis (2-oxazoline) compound, a polyvalent aromatic polyamine, and a dicarboxylic acid, and a part of the insulating resin is an unsaturated bond or activity on the carbon surface. Reacts with hydrogen and binds carbon black,
The difference (S0−V0) between the initial surface resistance (S0) and the initial volume resistance (V0) is the difference between the initial surface resistance (S0) and the surface resistance (S1) with time after passing the pulse current (S0−S1). ) Is larger than).
[0006]
In addition, it is preferable that a part of the insulating resin reacts with an unsaturated bond on the carbon surface, particularly π electrons or active hydrogen, and binds carbon black.
The insulating resin is preferably composed of at least one reaction product of a bis (2-oxazoline) compound, a polyvalent aromatic polyamine, and a dicarboxylic acid.
[0007]
As the insulating resin, a high-strength, high-modulus material such as polyimide resin, polyamideimide resin, polycarbonate resin, polyether sulfone resin, polyarylate resin, polyphenyl ether resin, or the like is selected. Since these thermoplastic resins have no reactivity with the carbon black surface, carbon black surfaces such as epoxy resins, polyurethane resins, vinyl ester resins, unsaturated polyester resins, acrylic ester resins, dicyclopentadiene resins, bismaleimide resins, etc. A thermosetting resin that reacts with an active bond such as an unsaturated bond or a carboxyl group or a hydroxyl group is required. These thermosetting resins can also be used alone. In addition, from the viewpoint of strength, durability, and processability, a reaction product of at least one of a bis (2-oxazoline) compound, a polyvalent aromatic polyamine, and a dicarboxylic acid is preferable.
[0008]
In detail, bis (2-oxazoline) compounds are already known and have the general formula:

(R ₀ represents a carbon-carbon bond or a divalent hydrocarbon group, and R ₁ , R ₂ , R ₃ , and R ₄ represent hydrogen, an alkyl group, or an aryl group, respectively). Specific examples include 2,2'-bis (2-oxazoline), 2,2'-bis (5-methyl-2-oxazoline), 2,2'-bis (5,5'-dimethyl-2-oxazoline) ), 2,2'-bis (4,4,4 ', 4'-tetramethyl-2-oxazoline), 1,2-bis (2-oxazolin-2-yl) ethane, 1,4-bis (2 -Oxazolin-2-yl) butane, 1,6-bis (2-oxazolin-2-yl) hexane, 1,8-bis (2-oxazolin-2-yl) octane, 1,4-bis (2-oxazoline) -2-yl) cyclohexane, 1,2-bis (2-oxazolin-2-yl) benzene, 1,3-bis (2-oxazolin-2-yl) benzene, 1,4-bis (2-oxazoline-2 -Yl) benzene, 1,2-bis (5-methyl-2-oxazolin-2-yl) benzene Zen, 1,3-bis (5-methyl-2-oxazolin-2-yl) benzene, 1,4-bis (5-methyl-2-oxazolin-2-yl) benzene, 1,4-bis (4 4'-dimethyl-2-oxazolin-2-yl) benzene and the like. Of these, use of 1,3-bis (2-oxazolin-2-yl) benzene having a particularly easy-to-handle melting point is preferred. These may be used alone or in combination.
[0009]
The polyvalent aromatic polyamine only needs to have at least two amino groups in the molecule, and may be a monocyclic or polycyclic compound. Specific examples of this polyaromatic polyamine include, for example, 4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diaminotriphenylmethane, 3,3 '-Dimethyl-4,4'-diaminobiphenyl, 2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 4,4'-methylenebisaniline, 4,4'-methylenebis (2- Chloroaniline), 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 3, , 4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-bis (aminophenyl) amine, 4,4 '-[1,3-phenylenebis (1-methyl) Chiriden)] bisaniline, 4,4 '- [1,4-phenylene bis (1-methylethylidene)] bisaniline, and the like. Among these polyvalent aromatic polyamines, 4,4′-methylenebisaniline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane and the like are preferable because of their availability.
[0010]
From the viewpoint of flexibility, 4,4′-diaminobiphenyl, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide and the like are preferable, and 4,4′-methylenebis (2-chloroaniline), 3 , 3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-5,5 '-Diethyl-4,4'-diaminodiphenylmethane and the like are particularly preferred because they have an effect of lowering the melt viscosity. These polyvalent aromatic polyamines may be used alone or as a mixture of two or more.
[0011]
Specific examples of the dicarboxylic acid include, for example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, maleic acid, fumaric acid, itaconic acid, Examples thereof include phthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, polyether glycol, polyester glycol, polycarbonate oligomer, NBR oligomer having both ends carboxylated. Among dicarboxylic acids, adipic acid, azelaic acid, terephthalic acid and the like are preferable. These dicarboxylic acids increase in elongation as the carbon number increases, and exhibit flexibility. Furthermore, when reacted with an excess of bis (2-oxazoline) compound in advance and then prepolymerized before reacting with the polyvalent aromatic polyamine, the distance between the crosslinking points can be increased, and flexibility is adjusted. It becomes possible. These dicarboxylic acids can also be used alone or as a mixture of two or more.
[0012]
The mixing molar ratio of the bis (2-oxazoline) compound (a), the polyvalent aromatic polyamine (b), and the dicarboxylic acid (c) is such that the oxazoline group of bis (2-oxazoline) is ring-opened to form an amine or carboxylic acid. Since it reacts with acid, (a) / ((b) + (c)) affects the crosslink density and must be greater than 1, otherwise less than enough Can not. Even if (a) / ((b) + (c)) is 2.0 or more, there is not much influence on the physical properties, but if it is too large, there is a tendency that the physical properties decrease beyond the peak. The melt viscosity of the mixture of the three components (a), (b), and (c) decreases as the ratio increases. However, the modulus and elongation sufficient to function as a belt such as an intermediate transfer belt can be obtained. 1.0 <(a) / ((b) + (c)) <= 3.0, 1.1 <(a) / ((b) + (c)) <= 2. 0 is more desirable.
In addition, dithiols such as 4,4′-thiobisbenzenethiol have high reactivity with bis (2-oxazoline) compounds and can be used in the same manner as dicarboxylic acids.
[0013]
Cationic catalysts are used as reaction catalysts for the above compounds. Specific examples include halides having at least one halogen atom bonded to a strong acid, sulfonic acid ester, sulfuric acid ester, Lewis acid, aliphatic or alicyclic carbon such as alkyl carbon or alkylene carbon. The catalyst may be used alone or in combination.
[0014]
Viscosity required for processing depends on the processing method. In general rotational molding, heat melting, if necessary, aromatics such as toluene and xylene, ketones such as acetone, MEK and MIBK, ethyl acetate, acetic acid A solution dissolved in an ester type such as butyl or carbitol acetate, an ether type such as monoglyme, diglyme or triglyme, or a nitrogen type single or mixed solvent such as dimethylacetamide, dimethylformamide or n-methylpyrrolidone is used. The viscosity of this solution is usually about 30 to 3,000 cp.
[0015]
Carbon black imparting a semiconductivity of 10 ⁸ to 10 ¹⁴ (Ω · cm) necessary for electrostatic adhesion or the like is selected from furnace black, oxidized furnace black, channel black, etc. There is a saturated bond, or active hydrogen such as a carboxyl group or a hydroxyl group, which reacts with a part of the insulating resin, and changes in the contact state of carbon black due to the influence of mechanical, thermal vibration, or current are suppressed. Even if the insulating resin does not directly react with carbon black, the same effect can be obtained by reacting with an unsaturated bond on the surface of carbon black or a compound bonded to active hydrogen.
However, if it reacts excessively, the viscosity of the resin solution before molding increases and becomes unstable, the resistance value becomes high, or the physical properties before molding deteriorate. It is necessary to reduce the reactivity by oxidization, silylation or amidation.
[0016]
This pretreatment will be explained by reacting an alcohol with a channel black having a primary particle size of 5 to 30 nm and a volatile content of 2 to 20% or an oxidized furnace black using a catalyst such as hydrochloric acid. Is generated. Alternatively, alkylation is carried out by methylation using dimethyl sulfate or the like, or by cation grafting vinyl monomers such as N-vinylcarbazole and methylstyrene. Further, a pretreated carbon black can be obtained by spraying and heating a silica agent such as methylchlorosilane and hexamethyldisilazane. Furthermore, it is possible to obtain a pretreated carbon black by refluxing an isocyanate or an oxazoline compound in a solvent.
[0017]
The isocyanate and oxazoline compounds react efficiently with the active hydrogen content on the surface of the carbon black to generate amide bonds and urethane bonds having active hydrogen, so that a part of the insulating resin reacts. Although furnace black does not have a reactive group, pretreatment carbon black can be obtained by reacting acyl chloride under a Lewis acid catalyst or radical reaction of decomposition products of azo compounds and peroxide compounds. it can.
[0018]
As the monomer to be reacted has a higher molecular weight or a larger amount to be reacted, the reactivity of the carbon black is lowered and can be appropriately supplemented with an insulating resin. However, if it is excessive, supplementation will be insufficient, and carbon black will move and rearrange, so care must be taken. The state of pretreatment of carbon black can be quantified by measuring the pH of carbon black or performing alkali titration.
[0019]
In addition, fillers such as silica, alumina, titanium oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, talc, and clay can also be used as desired in the field of synthetic resin molding. However, it is necessary to avoid those that cause thickening. Moreover, it is possible to use arbitrary additives such as stabilizers, antioxidants, internal mold release agents, pigments, dispersants, flame retardants and the like used in the field of ordinary synthetic resin molding.
[0020]
Next, the manufacturing method of the seamless belt which concerns on this invention is demonstrated. First, the material for the seamless belt is adjusted. In this case, an appropriate concentration, viscosity, and solvent boiling point are selected from the processing time and temperature. When the processing time, temperature, and the like are selected in this manner, a necessary solvent is added to the insulating resin (at least part of the thermosetting resin) to obtain a resin stock solution.
[0021]
Next, the carbon black is sufficiently undissolved in a normal dispersion apparatus such as a pot mill, a cycloid mill, an apex mill, a dinol mill, an attritor mill, a jet mill or the like in a solution state or a dry state to form primary aggregates. Once the primary agglomerates are obtained, they are reacted with the monomer in a wet or dry manner, and if necessary, washed and dried to prepare pretreated carbon black, which is dispersed and mixed in the resin stock solution to produce a semiconductive solution or melt. A slurry is obtained.
[0022]
Next, a curing agent or a catalyst is added to the slurry and poured into a tubular mold that has been rotated in advance. At this time, the melt viscosity of the slurry is preferably 50 poise or less. This is because if it exceeds 50 poise, it is difficult to obtain a uniform film thickness. The centrifugal mold is rotated at about 500 to 3,000 rpm and heated to 120 to 200 ° C. The drying and reaction time for volatilizing the solvent needs about 45 to 200 minutes. However, in the case of the thermosetting resin alone, the heating time is short and may be about 5 to 30 minutes. Thus, if predetermined time passes and a metal mold | die is cooled to room temperature after that, the endless flexible seamless belt which has a thickness of 50-200 micrometers can be produced.
[0023]
By the way, the resistance value of the seamless belt gradually decreases as the number of times of printing increases due to the applied voltage for adhesion and peeling. Therefore, in anticipation of reliable adhesion and peeling of toner and paper, a surface resistance value that is approximately two orders of magnitude higher than the volume resistance value is desired in the initial stage, and tens of thousands to hundreds of thousands of printings are desired. Even after that, the decrease in surface resistance is about two orders of magnitude or less, which is a practical limit. Although it takes time to confirm this actual change with time, it can be determined by an accelerated test.
[0024]
That is, if a seamless belt is sandwiched with two sheets of conductive elastic electrodes together with printing paper, a pulse current of 0.02 mA / cm ² or less is applied to the seamless belt at a pulse number of 5 to 10 times the number of durable printings, The change in resistance value can be confirmed. The applied voltage at this time varies depending on the resistance of the seamless belt and the electrode area of the elastic electrode, but is approximately several hundred to several thousand volts. An arbitrary measuring device can be used for the measurement of resistance, but a Hiresta [trade name] manufactured by Mitsubishi Chemical Corporation is generally used.
[0025]
【Example】
Examples of seamless belts according to the present invention will be described below together with comparative examples.
Preparation of Example 1 First, 800 g of polyethersulfone (trade name 4800G, manufactured by Sumitomo Chemical Co., Ltd.), 200 g of bisphenol A type epoxy resin with an epoxy equivalent of 475, and 100 g of polyamide-based curing agent (trade name, manufactured by Asahi Denka Co., Ltd.) EH-333] was dissolved in N-methylpyrrolidone and toluene (mixed wt ratio 9: 1) to prepare a resin solution having a solid content of 15%. The viscosity of this resin solution was 6 poise.
[0026]
Once the resin solution is prepared, furnace black (trade name # 2400, manufactured by Mitsubishi Chemical Corporation) is reacted in 3N nitric acid at 60 ° C. for 1 hour, filtered, washed with water, and dried carbon black. The slurry was mixed with 1.7% by weight and dispersed and mixed in a bead mill for 16 hours. When the slurry was thus obtained, this slurry was poured into a mold rotating at 1,000 rpm, dried and cured for 50 minutes, and then the mold was cooled to room temperature to prepare Sample A. The mold was a φ200 mm steel pipe with an inner peripheral surface plated with chromium, and was heated at 135 ° C. The slurry was further refluxed at 135 ° C. for 50 minutes to prepare Sample B in the same manner as described above and used for confirming the reaction with the insulating resin.
[0027]
Preparation of Example 2 First, 238 g (1.1 mol) of 1,3-bis (2-oxazolin-2-yl) benzene and 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] Bisaniline (275 g, 0.8 mol) and 4,4′-thiobisbenzenethiol (50 g, 0.2 mol) were weighed, placed in a 150 ° C. oil bath and stirred with a mixer. When the mixture was stirred in this manner, all melted after about 15 minutes, and the mixture was further stirred for 2 hours to prepare a thermosetting resin stock solution. This thermosetting resin stock solution was cooled to 120 ° C., mixed with 280 g of a dimethylformamide solution of polycarbonate [trade name K1285 manufactured by Teijin Chemicals Ltd.], and the solvent was evaporated over 10 hours to obtain a resin stock solution. The viscosity of this resin stock solution was 12 poise at 120 ° C.
[0028]
Then, 8 wt% of phenyl isocyanate was reacted in the ethyl acetate solution with channel black (trade name 150T, manufactured by Degussa Co., Ltd.) in an ethyl acetate solution for 1 hour. 4.8 wt% of the dried pretreated carbon black was blended with respect to the solid content of the resin stock solution, and dispersed and mixed with a high-speed stirrer for 16 hours. When the slurry is thus obtained, 2 phr of octyl bromide is added and mixed with the slurry, and the slurry is immediately poured into a rotating mold at 2,000 rpm, dried and cured for 15 minutes, and then the mold is cooled to room temperature. Thus, sample A was prepared. The mold was a φ200 mm steel pipe with an inner peripheral surface plated with chromium, and heated at 145 ° C. The slurry was further heated at 145 ° C. for 15 minutes to prepare Sample B in the same manner as described above, and used for confirming the reaction with the insulating resin.
[0029]
Preparation of Example 3 First, 303 g (1.4 mol) of 1,3-bis (2-oxazolin-2-yl) benzene and 198 g (1.0 mol) of 4,4′-methylenebisaniline were weighed. In a 150 ° C. oil bath, the container was taken and stirred with a mixer. When the mixture was stirred in this manner, all melted after about 15 minutes, and the mixture was further stirred for 2 hours to prepare a thermosetting resin stock solution. The viscosity of this thermosetting resin stock solution was 2 poise at 120 ° C. Oxidized channel black (trade name # 550, manufactured by Degussa Co., Ltd.) 8 wt% phenyloxazoline was reacted with this thermosetting resin stock solution in an ethyl acetate solution at 80 ° C. for 3 hours.
[0030]
4.8 wt% of the dried pretreated carbon black was blended with respect to the solid content of the resin stock solution, and dispersed and mixed with a high-speed stirrer for 16 hours. When the slurry is thus obtained, 2 phr of octyl bromide is added to and mixed with the slurry, and the slurry is immediately poured into a rotating mold at 2,000 rpm, dried and cured for 10 minutes, and then the mold is cooled to room temperature. Thus, sample A was prepared. The mold was a φ200 mm steel pipe with an inner peripheral surface plated with chromium, and heated at 140 ° C. The slurry was further heated at 145 ° C. for 50 minutes to prepare Sample B in the same manner as described above and used for confirming the reaction with the insulating resin.
[0031]
Sample A and Sample B were prepared in the same manner as in Example 1 except that the adjusted carbon black of Comparative Example 1 was not oxidized.
Preparation of Comparative Example 2 Polyamideimide varnish [trade name NX100 manufactured by Toyobo Co., Ltd.] (solid content 15%, solvent, N-methylpyrrolidone), the pretreated carbon black shown in Example 2 was added to the solid content of the resin solution. 2.1 wt% was blended and dispersed and mixed in a bead mill for 16 hours to obtain a slurry. The obtained slurry was processed in the same manner as in Example 2 to prepare Sample A and Sample B.
[0032]
The volume resistances of the reaction confirmation samples A and B were measured with a high-reester. In this measurement, 500 V was applied, and the average value of five measurements was calculated.
The volume resistance and surface resistance of the accelerated test sample A and sample B were measured with a high-rester. In this measurement, 500 V was applied, and the average value of five measurements was calculated. Subsequently, a printing paper was placed on the sample A, sandwiched between conductive silicone rubber electrodes (specific resistance 5 Ω · cm) having a thickness of 1 mm, and a weight was placed so as to be 20 gf / cm ² . After placing the weight in this way, a commercial wave high voltage was applied at a constant voltage so that a current of 0.015 mA / cm ² would flow through the conductive silicone rubber electrode, and after 16 hours of application, the surface resistance was measured again.
[0033]
[Table 1]

[0034]
【The invention's effect】
As described above, according to the present invention, since a part of the insulating resin reacts with carbon black, it is possible to regulate minute movement that causes rearrangement of carbon black as the number of printings increases. Through this, it is possible to provide a seamless belt with extremely high industrial utility value that can suppress the occurrence of printing defects such as faint printing, smudges, misalignment, etc. and can be expected to be used for a long period of time. There is an effect that can be done.
In addition, since the insulating resin is a reaction product of at least one of a bis (2-oxazoline) compound, a polyvalent aromatic polyamine, and a dicarboxylic acid, excellent strength, durability, and processability can be obtained. In addition, changes in the contact state of the carbon black due to the influence of mechanical, thermal vibration, or current can be suppressed.

Claims (1)

It is a semiconductive seamless belt in which carbon black is dispersed and mixed in an insulating resin and is centrifugally molded .
The insulating resin is composed of a reaction product of at least one of a bis (2-oxazoline) compound, a polyvalent aromatic polyamine, and a dicarboxylic acid, and a part of the insulating resin is an unsaturated bond or activity on the carbon surface. Reacts with hydrogen and binds carbon black,
The difference (S0−V0) between the initial surface resistance (S0) and the initial volume resistance (V0) is the difference between the initial surface resistance (S0) and the surface resistance (S1) after passing the pulse current (S0−S1). ) Seamless belt characterized by being larger than.