JP3610926B2 - Molded member, endless belt, belt for image forming apparatus, and image forming apparatus - Google Patents

Description

【００７２】
（（Ｉ）式中、Ｒ^１，Ｒ^２，Ｒ^３はそれぞれ独立に水素又は炭素数１〜２０のアルキル基又はアリール基であり、Ｚは単結合又は酸素原子で少なくともその一つは酸素原子である。）
【００７３】
リン酸エステルの具体例としてはリン酸トリエチル、リン酸トリブチル、リン酸トリフェニル等が挙げられる。
【００７４】
また、亜リン酸エステルとしては下記一般式（ＩＩ）〜（ＩＶ）で示されるものが挙げられる。
【００７５】
【化２】

【００７６】
（（ＩＩ）式中、Ｒ^４，Ｒ^５，Ｒ^６はそれぞれ独立に炭素数１〜２０のアルキル基、アリール基、シクロアルキル基、アルアルキル基、アルキルアリール基を示し、Ｚは単結合又は酸素原子で少なくとも一つは酸素原子である。）
【００７７】
その具体例としては、トリエチルホスファイト、トリブチルホスファイト、トリス（２−エチルヘキシル）ホスファイト、トリデシルホスファイト、トリステアリルホスファイト、トリフェニルホスファイト、トリクレジルホスファイト、トリス（ノニルフェニル）ホスファイト、トリス（２，４−ジ−ｔ−ブチルフェニル）ホスファイト、デシル−ジフェニルホスファイト、フェニル−ジ−２−エチルヘキシルホスファイト、フェニル−ジデシルホスファイト、トリス（ビフェニル）ホスファイト、トリシクロヘキシルホスファイト等が挙げられる。
【００７８】
【化３】

【００７９】
（（ＩＩＩ）式中、Ｒ^７，Ｒ^８，Ｒ^９，Ｒ^１０はそれぞれ独立に（ＩＩ）式のＲ^４，Ｒ^５，Ｒ^６の定義に属するものであり、Ｚは（ＩＩ）式のＺと同一定義のものである。Ｙは炭素数１〜３０のアルキレン基、アリーレン基、シクロアルキレン基、アルアルキレン基、アルキルアリーレン基を示す。）
【００８０】
その具体例としては、テトラフェニル−４，４’−イソプロピリデン−ジフェノールジホスファイト、テトラトリデシル−４，４’−イソプロピリデン−ジフェノールジホスファイト、テトラトリデシル−４，４’−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）ジホスファイト、テトラキス（２，４−ジ−ｔ−ブチルフェニル−４，４’−ビフェニレン）ホスファイト等が挙げられる。
【００８１】
【化４】

【００８２】
（（ＩＶ）式中、Ｒ^１１は炭素数１〜３０のアルキル基、アリール基、シクロアルキル基、アルアルキル基、アルキルアリール基であり、Ｒ^１２は炭素数１〜２０のアルキレン基であり、Ｚは式（ＩＩ）のＺと同一定義のものである。）
【００８３】
その具体例としては、ビス（ステアリル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（ノニルフェニル）ペンタエリスリトールジホスファイト等が挙げられる。
【００８４】
上記した各種の化合物の内でも、特にトリブチルホスファイト、トリフェニルホスファイト、ビス（ステアリル）ペンタエリスリトールジホスファイト及びビス（２，６−ジ−ｔ−ブチルフェニル）ペンタエリスリトールジホスファイトが好ましい。
【００８５】
（キレーターの配合量）
樹脂組成物中のキレーターの配合量は特に規定しないが、少ないと反応抑制剤としての添加効果を殆ど発揮せず、ある程度の濃度を超えた時点から顕著に効果を発揮する。従って、本発明においては、成分Ａ〜Ｄの合計重量に対してＴｉにキレートする元素重量として好ましくは１００ｐｐｍ以上、より好ましくは３００ｐｐｍ以上、特に好ましくは５００ｐｐｍ以上とする。なお、キレーターの配合量が多過ぎるとＴｉ系化合物の触媒活性が失われ、良好な成形部材が得られなくなるため、成分Ａ〜Ｄの合計重量に対してＴｉにキレートする元素重量として６０００ｐｐｍ以下、特に３０００ｐｐｍ以下とする。なお、以下において、成分Ａ〜Ｄの合計重量に対するキレーターのＴｉにキレートする元素の重量割合を「キレート元素濃度」と称す場合がある。
【００８６】
（成分Ｅ；導電性物質）
導電性物質としては、分散性に優れているカーボンブラックが用いられる。
【００８８】
カーボンブラックの種類としては、アセチレンブラック、ファーネスブラック、チャンネルブラックなどが好適に使用でき、この中でも不純物としての官能基が少なくカーボン凝集による外観不良を発生しにくいアセチレンブラックが特に好適に使用できる。さらに一次粒子径が１０〜１００ｎｍ、比表面積１０〜２００ｍ^２／ｇ，ｐＨ値３〜１１のものがより好ましい。
【００８９】
また、使用するカーボンブラックは１種類であっても２種類又はそれ以上であっても良い。さらには、カーボンブラックには樹脂を被覆したカーボンブラックや、黒鉛化処理したカーボンブラックや、酸性処理したカーボンブラック等の公知の後処理工程を施したカーボンブラックを用いても何ら問題はない。
【００９０】
また、導電性物質の分散性を向上させる目的でシラン系、アルミネート系、チタネート系、又はジルコネート系等のカップリング剤で処理したカーボンブラック等の導電性物質を用いても良い。
【００９１】
（導電性物質の配合量）
樹脂組成物中の導電性物質の配合量としては、使用する導電性物質の物性により発現する抵抗値は変化するので、所望する抵抗値が得られる導電性物質濃度を見極めて設定する必要がある。本発明においては、成分Ａ〜Ｅの合計重量に対するカーボンブラックの割合（以下、「カーボンブラック濃度」と称す場合がある。）を、１〜５０重量％、好ましくは３〜３０重量％、特に好ましくは１０〜２５重量％とする。上記範囲を超えると製品の外観が悪くなり、また、材料強度が低下して好ましくない。また、上記範囲より少ないと、導電性の付与に関する効果が小さく、好ましくない。
【００９２】
（付加的配合材；任意成分）
本発明の成形部材を構成する樹脂組成物には、各種目的に応じて任意の配合成分を配合することができる。
【００９３】
具体的には、日本チバガイギー社製イルガノックス１０１０（商品名）などの酸化防止剤、熱安定剤、各種可塑剤、光安定剤、紫外線吸収剤、中和剤、滑剤、防曇剤、アンチブロッキング剤、スリップ剤、架橋剤、架橋助剤、着色剤、難燃剤、分散剤等の各種添加剤を添加することができる。
【００９４】
更に、本発明の効果を著しく損なわない範囲内で、第２，第３成分として各種熱可塑性樹脂、各種エラストマー、熱硬化性樹脂、フィラー等の配合材を配合することができる。
【００９５】
付加成分としての熱可塑性樹脂としてはポリプロピレン、ポリエチレン（高密度，中密度，低密度，直鎖状低密度）、プロピレンエチレンブロック又はランダム共重合体、ゴム又はラテックス成分、例えばエチレン・プロピレン共重合体ゴム、スチレン・ブタジエンゴム、スチレン・ブタジエン・スチレンブロック共重合体又は、その水素添加誘導体、ポリブタジエン、ポリイソブチレン、ポリアミド、ポリアミドイミド、ポリアセタール、ポリアリレート、ポリカーボネート、ポリイミド、液晶性ポリエステル、ポリスルフォン、ポリフェニレンサルファイド、ポリビスアミドトリアゾール、ポリエーテルイミド、ポリエーテルエーテルケトン、アクリル、ポリフッ素化ビニリデン、ポリフッ素化ビニル、クロロトリフルオロエチレン、エチレンテトラフルオロエチレン共重合体、ヘキサフルオロプロピレン、パーフルオロアルキルビニルエーテル共重合体、アクリル酸アルキルエステル共重合体、ポリエステルエステル共重合体、ポリエーテルエステル共重合体、ポリエーテルアミド共重合体、ポリウレタン共重合体等の１種又はこれらの２種以上の混合物からなるものが使用できる。
【００９６】
熱硬化性樹脂としては、例えばエポキシ樹脂、メラミン樹脂、フェノール樹脂、不飽和ポリエステル樹脂等の１種又はこれらの２種以上の混合物からなるものが使用できる。
【００９７】
また、各種フィラーとしては、例えば炭酸カルシウム（重質、軽質）、タルク、マイカ、シリカ、アルミナ、水酸化アルミニウム、ゼオライト、ウオラストナイト、けいそう土、ガラス繊維、ガラスビーズ、ベントナイト、アスベスト、中空ガラス玉、黒鉛、二硫化モリブデン、酸化チタン、炭素繊維、アルミニウム繊維、スチレンスチール繊維、黄銅繊維、アルミニウム粉末、木粉、もみ殻、グラファイト、金属粉、導電性金属酸化物、有機金属化合物、有機金属塩等のフィラーの他、添加剤として酸化防止剤（フェノール系、硫黄系、リン酸エステル系など）、滑剤、有機・無機の各種顔料、紫外線防止剤、帯電防止剤、分散剤、中和剤、発泡剤、可塑剤、銅害防止剤、難燃剤、架橋剤、流れ性改良剤等を挙げることができる。
【００９８】
次に、本発明における溶融混練、成形方法、成形品の物性、用途等について説明する。
【００９９】
（溶融混練、成形）
本発明においては、前述の成分Ａ〜Ｅ、及び必要に応じて添加される上記付加成分を加熱混練後、所望の形に成形、固化して成形部材とするが、これらの成分を加熱混練により成形部材として一度ペレット形状に成形し、このペレットをさらに溶融成形して別な形の成形部材に成形する方法が特に好ましい。
【０１００】
このような溶融混練工程において、本発明では重合触媒としてのＴｉ系化合物と、Ｐ系化合物等のキレーターとの作用で良好な効果を得るために、次のような条件設定を行うことが重要となる。
【０１０１】
即ち、Ｔｉ系化合物が触媒として作用したときの反応性は以下の特徴を有している。
【０１０２】
▲１▼ 低温（熱可塑性結晶性エステル系樹脂の融点〜＋４０ｄｅｇ程度）では共重合化、高分子量化、解重合が拮抗した競争反応となる。定量化は難しいが、おおむね低温短時間（約１〜５分程度）では共重合化と高分子量化が優勢になりやすく、長時間（約５〜１０分以上）では解重合が優勢になる場合が多い。
【０１０３】
▲２▼ 高温（熱可塑性結晶性エステル系樹脂融点＋４０ｄｅｇ〜＋８０ｄｅｇ程度）条件下では（時間の長短によらず）解重合が優勢になる場合が多い。
【０１０４】
そのため、比較的低温で加熱混練、溶融成形を施す必要があるが、あまりに時間が短すぎると共重合化も高分子量化も進行しないため高物性が発現せず、逆に時間が長すぎると解重合が優勢になって劣化してしまうことから、最適な滞留時間を見極めながら加工条件を選択する必要があった。
【０１０５】
これに対して、キレーターとして、例えばＰ系化合物を配合した場合、生成したＴｉ−Ｐ錯体は、活性が緩くなっているため共重合化や高分子量化の反応速度は遅くなっているが、元のＴｉ系化合物と比べて、次のような反応性を示す。
【０１０６】
▲１▼ 低温（熱可塑性結晶性エステル系樹脂の融点〜＋４０ｄｅｇ程度）では共重合化、高分子量化、解重合とも反応性が低いので進行しにくい。
【０１０７】
▲２▼ 高温（熱可塑性結晶性エステル系樹脂の融点＋４０ｄｅｇ〜＋８０ｄｅｇ程度）では、短時間（約１〜５分程度）の場合共重合化と高分子量化の反応が優先し、長時間（約５分以上）では共重合化と高分子量化と解重合が拮抗あるいは解重合の反応が優先することが多い。
【０１０８】
従って、本発明において、好適な加工手段の一例としては、各成分を加熱混練してペレット化するときに溶融状態を高温短時間（例えば樹脂温度で熱可塑性結晶性エステル系樹脂の融点＋４０〜＋８０ｄｅｇ、好ましくは＋６０ｄｅｇ程度；溶融状態での滞留時間０．５〜５分、好ましくは約１分）になるように調整し、加熱混練時の段階で共重合化と高分子量化の反応を施す。この加熱混練の手段に特に制限はなく公知の技術を用いることができ、例えば、一軸押出機、二軸混練押出機、バンバリーミキサー、ロール、ブラベンダー、プラストグラフ、ニーダーなどを用いることができ、二軸混練押出機を特に好適に用いることができる。
【０１０９】
次に、このペレットを低温（熱可塑性結晶性エステル系樹脂の融点＋０〜＋４０ｄｅｇ、好ましくは＋３０ｄｅｇ程度）で溶融成形して成形部材を得る。このようにして成形部材を得る場合でも公知の技術を用いることができ、例えば射出成形機、押出成形機などを用いることができる。このような低温ではＴｉ−Ｐ錯体は解重合を促進することは殆どないので成形条件（滞留時間など）が多少変動しても解重合が進行することはない。また、共重合化，高分子量化は既にほぼ終了しているので、滞留時間が短くなっても高物性が発現できる。
【０１１０】
この手法ではＴｉ−Ｐ錯体の触媒としての反応性の特徴を利用して、加熱混練によるペレット化時に共重合化，高分子量化の反応を促進すること、ペレットの溶融成形には共重合化，高分子量化，解重合の反応を抑制することが重要になる。
【０１１１】
Ｔｉ−Ｐ錯体は、６０〜１５０℃で０．５〜１０時間程度加熱しておくと、触媒能が一時的に高くなるので加熱混練前にＴｉ系化合物のみ或いはＴｉ系化合物を含む混練原料を６０〜１５０℃で０．５〜１０時間程度に事前に加熱しておいて共重合化と高分子量化の反応速度を高めることも有効である。事前の加熱により触媒能が高くなる理由は明らかではないが、通常の状態ではＴｉ系化合物は空気中の水を結晶水として取り込むことで触媒能が低下しているが、これを加熱して結晶水を除去してやることで触媒能が高くなるためと考えられる。
【０１１２】
（熱可塑性結晶性エステル系樹脂と熱可塑性非晶性エステル系樹脂との化学結合）
本発明においては、熱可塑性結晶性エステル系樹脂の分子鎖と熱可塑性非晶性エステル系樹脂の分子鎖間の化学結合を形成することにより、両樹脂間の親和性向上、形態の微分散化を促し、熱可塑性結晶性エステル系樹脂の高耐屈曲性と熱可塑性非晶性エステル系樹脂の寸法安定性、（条件によっては更に透明性）を併せ持つ成形部材を得ることができる。
【０１１３】
化学結合の存在比率としては特に制限は無いが、基本的には多い方が好ましく、具体的には熱可塑性結晶性エステル系樹脂の分子鎖と熱可塑性非晶性エステル系樹脂の分子鎖間の化学結合１モルあたりの、熱可塑性結晶性エステル系樹脂と熱可塑性非晶性エステル系樹脂との合計質量（以下、この質量を「対化学結合質量」と称す。）が、１，０００，０００ｇ以下となることが好ましく、３００，０００ｇ以下となることがさらに好ましく、１００，０００ｇ以下となることが特に好ましい。
【０１１４】
この化学結合の量の測定方法に特に制限はないが、例えばＮＭＲにより測定することができる。
【０１１５】
熱可塑性結晶性エステル系樹脂としてＰＢＴ、熱可塑性非晶性エステル系樹脂としてＰＣを用いた場合の測定例を次に示す。
測定機種 ＪＥＯＬＧＳＸ４００
溶媒 １，１，１，２，２，２−ヘキサフルオロイソプロパノール／ｄ−クロロホルム＝３／７（体積比）
積算回数 １２８回
基準 ＴＭＳ
【０１１６】
この測定により、図１，２に示すチャートを得た。なお、図２は図１のＩＩ部分を拡大したものである。
【０１１７】
テレフタル酸（ＴＰＡ）のベンゼン環水素はカルボン酸がブタンジオールと結合している場合とビスフェノールＡ（ＢＰＡ）とで化学シフトが異なることから、ＰＢＴ分子鎖中のＴＰＡとＰＢＴ−ＰＣ結合しているＴＰＡとの量比を求めることができる。
【０１１８】
（熱可塑性結晶性エステル系樹脂と熱可塑性非晶性エステル系樹脂の分散形態）
一般に２種類の熱可塑性樹脂を溶融混合しても完全には混じり合わず、海島構造をとることが知られている。両熱可塑性樹脂の体積分率に大きな差が有る場合は体積分率の大きい方が海で体積分率が小さい方が島の構造をとりやすく、体積分率の差が小さい場合は溶融粘度差が海島構造に影響を与え、溶融粘度の小さい方が海に、大きい方が島になりやすいと云われている。
【０１１９】
一般的な溶融混合では分散粒径が１００ｎｍ程度にしかならないが、本発明においては条件を適正化することにより分散粒径を数ｎｍ以下にまで微細化することが可能で、これにより事実上成形部材を透明化することができる。一般に、ＰＢＴなどの熱可塑性結晶性エステル系樹脂を含む成形部材は透明性を有さないことで知られるが、本発明による手法を用いれば、透明な成形部材を得ることもできる。
【０１２０】
分散状態の確認手法に特に制限はなく、ＲｕＯ_４で染色後、超薄切片を作成しＴＥＭで観察するなどの公知の方法を用いることができる。
【０１２１】
（本発明の成形部材の用途）
本発明の成形部材の用途に特に制限はなく、ＯＡ機器の構成部品，機能部材、自動車の外装部品，内装材、家電機器の構成部材、汎用フィルムなどとして幅広く用いることができる。
【０１２２】
なかでも寸法精度，耐屈曲性，引張破断伸びなど要求物性の厳しいＯＡ機器分野、特に機能部材には好適に用いることができ、例えばエンドレスベルト形状として、電子写真式複写機、レーザービームプリンター、ファクシミリ機等の画像形成装置に中間転写ベルト，搬送転写ベルト，感光体ベルトなどとして用いると、割れ，伸びなど不具合が少ないので好適である。
【０１２３】
以下に、本発明の成形部材の好適な使用例の一例としてのエンドレスベルトについて説明する。
【０１２４】
（エンドレスベルト）
本発明のエンドレスベルトを得るには、前述の成分Ａ〜Ｅ、及び必要に応じて配合されるその他の付加成分を例えば二軸混練押出機により混合し、ペレット化した後にエンドレスベルトとなるように成形する手法が特に好ましく用いられる。
【０１２５】
成形方法については、特に限定されるものではなく、連続溶融押出成形法、射出成形法、ブロー成形法、あるいはインフレーション成形法など公知の方法を採用して得ることができるが、特に望ましいのは、連続溶融押出成形法である。特に押し出したチューブの内径を高精度で制御可能な下方押出方式の内部冷却マンドレル方式あるいはバキュームサイジング方式が好ましく、内部冷却マンドレル方式が最も好ましい。
【０１２６】
また、この成形時の温度，滞留時間の適正化により、より良好な物性のエンドレスベルトを得ることができるので、各配合にあわせて条件を調整することが好ましい。
【０１２７】
（エンドレスベルトの物性）
本発明によれば、以下のような物性を有するエンドレスベルトを得ることができる。
【０１２８】
・耐折回数
本発明のエンドレスベルトを例えば中間転写ベルトとして画像形成装置に用いる場合、耐屈曲性が悪いとクラックが発生して画像が得られなくなることから、耐屈曲性の良好なエンドレスベルトが好ましい。
【０１２９】
耐屈曲性の程度は、ＪＩＳ Ｐ−８１１５の耐折回数の測定方法に従うことで定量的に評価でき、耐折回数の大きいエンドレスベルトほどクラックが入りにくく、耐屈曲性に優れていると判断することができる。
【０１３０】
具体的な数値としては、５００回以上であれば一応エンドレスベルトとしての機能を発揮して使用することができるが、実用的には５０００回以上が好ましく、１００００回以上であれば更に好ましく、３００００回以上であれば、特にクラックが発生しにくくなるので特に好ましい。
【０１３１】
・引張弾性率
エンドレスベルトの引張弾性率が低いと、例えば中間転写ベルトとして画像形成装置に用いる場合に張力により少し伸びが発生してしまい、色ズレなど不具合を発生することがあるので引張弾性率が高い方が好ましく、具体的には１０００ＭＰａ以上が好ましく、１５００ＭＰａ以上であるとさらに好ましく、２０００ＭＰａ以上であるとさらに好ましく、２５００ＭＰａ以上であれば色ズレなどの不具合を大幅に抑えることができるので特に好ましい。
【０１３２】
一般に柔らかいプラスチックは耐折回数が高いが引張弾性率が低くなりやすく、逆に硬いプラスチックは高い引張弾性率を得られるが脆くなりやすく耐折回数は低いものしか得られないことが多い。本発明ではＰＢＴやＰＣの有する固有の高い引張弾性率の特性を維持したまま、高い耐折回数を得ることができる意味で有用であると言える。
【０１３３】
・表面抵抗率
本発明のエンドレスベルトでは導電性物質、好ましくはカーボンブラックを配合することにより導電性を得る。エンドレスベルトの抵抗領域は目的により異なるが、表面抵抗率１〜１×１０^１６Ωの範囲から選定することが好ましい。
【０１３４】
表面抵抗率の更に好ましい範囲は用途により異なるが、例えば感光体ベルトとして用いる場合には必要に応じて外表面の電荷を内表面に逃がせるように１〜１×１０^６Ωと低い表面抵抗率が好ましく、中間転写ベルトとして用いる場合には帯電−転写の容易にできる１×１０^６〜１×１０^１１Ωが好ましく、搬送転写ベルトとして用いる場合には帯電しやすく高電圧でも破損しにくい１×１０^１０〜１×１０^１６Ωと高い領域が好ましい。
【０１３５】
また、エンドレスベルト１本中の表面抵抗率の分布は狭い方が好ましく、それぞれの好ましい表面抵抗率領域において、１本中の最大値が最小値の１００倍以内であることが好ましく、１０倍以内であることが特に好ましい。
【０１３６】
エンドレスベルトの表面抵抗率は例えばダイヤインスツルメント（株）製ハイレスタ，ロレスタやアドバンテスト（株）製Ｒ８３４０Ａなどにより容易に測定することができる。
【０１３７】
・エンドレスベルトの厚み
エンドレスベルトの厚みは５０〜１０００μｍが好ましく、８０〜５００μｍが更に好ましく、１００〜２００μｍであれば特に好ましい。
【０１３８】
（エンドレスベルトの用途）
本発明のエンドレスベルトは、電子写真式複写機、レーザービームプリンター、ファクシミリ機等の画像形成装置に中間転写ベルト、搬送転写ベルト、感光体ベルトなどとして用いた場合、割れ、伸びなど不具合が少なく、長期に亘り安定に使用することができる。
【０１３９】
【実施例】
以下に実施例及び比較例を挙げて、本発明をより具体的に説明する。
【０１４０】
以下の実施例及び比較例では、下記の原料及び成形条件でエンドレスベルトを製造し、その評価を行なって結果を表１に示した。
【０１４１】
（原料）
原料は下記のものを用い、配合割合は表１の通りとした。
成分Ａ：ＰＢＴ（重量平均分子量４０，０００；ＰＳ換算重量平均分子量１２２，０００）
成分Ｂ：ＰＣ（重量平均分子量２８，０００；ＰＳ換算重量平均分子量 ６４，０００）
成分Ｃ：Ｔｉ系化合物（チタニウム（ＩＶ）ブトキシド）
成分Ｄ：Ｐ系化合物（サンドスタブＰ−ＥＰＱ：テトラキス（２，４−ジターシャリブチルフ
ェニル）４，４’−ビフェニリレンジホスホナイト（構造式は下記の通り）；クラリアントジャパン（株）製）
又はヒドラジン類（ＩＲＧＡＮＯＸ ＭＤ１０２４；日本チバガイギー（株）製）
【０１４２】
【化５】

【０１４３】
成分Ｅ；カーボンブラック（デンカブラック；電気化学（株）製）
【０１４４】
なお、成分Ａと成分Ｂについて、前述の方法で測定したＭＦＲ（２６０℃ ２．１６ｋｇ）は各々成分Ａ：７ｇ／１０ｍｉｎ、成分Ｂ：３ｇ／１０ｍｉｎであり、両樹脂のＭＦＲ比は２．３３／１である。
【０１４５】
（加熱混練）
各原料を、二軸混練押出機（ＩＫＧ（株）製 ＰＭＴ３２）を用いて樹脂組成物をペレット化した。なお、熱可塑性樹脂は混練前に１３０℃で８時間乾燥し、さらに６０℃程度まで冷ましてから混練に用いた。混練条件は混練機の設定温度を２４０℃とし、スクリュー回転数１００ｒｐｍ、吐出速度１５ｇ／ｈとした。本条件での混練機内での溶融状態での滞留時間は平均で約２分程度である。
【０１４６】
（エンドレスベルトの成形方法）
この材料ペレットを１３０℃で８時間乾燥し、直径φ１８０ｍｍ、リップ幅１ｍｍの６条スパイラル型環状ダイ付き４０ｍｍφの押出機により、環状ダイ下方に溶融チューブ状態で押し出し、押し出した溶融チューブを、環状ダイと同一軸線上に支持棒を介して装着した外径１７０ｍｍの冷却マンドレルの外表面に接しめて冷却固化させつつ、次に、シームレスベルトの中に設置されている中子と外側に設置されているロールにより、シームレスベルトを円筒形に保持した状態で引き取りつつ３４０ｍｍ長の長さで輪切りにして下記に記載の厚み、滞留時間となるよう押出量、引き取り速度を調整し、直径１６９ｍｍの樹脂製シームレスベルトとした。なお、エンドレスベルトの物性の滞留時間依存性を評価するため、滞留時間を調節し、下記の２種類の条件で成形した。
【０１４７】
条件Ａ；滞留時間１２分、厚み１５０μｍを目標とし、厚みの範囲が±１５μｍになるように調整して成形
条件Ｂ；滞留時間２４分、厚み１５０μｍを目標とし、厚みの範囲が±１５μｍになるように調整して成形
【０１４８】
この条件Ｂでは、条件Ａより滞留時間が長くなるようスクリューの回転を遅くして成形すると共に、条件Ａとベルト厚みが同じになるように引取速度も遅く調整して成形した。
【０１４９】
（評価）
評価は必要に応じ、エンドレスベルトを適当な大きさに切り開いて実施した。
【０１５０】
・耐折回数
ＪＩＳ Ｐ−８１１５準拠
各サンプルで３回づつ測定し、平均値（有効数字２桁）を代表値とした。耐折回数は、耐屈曲疲労性の指標で数字が大きいほど割れにくく丈夫であることを意味する。
【０１５１】
・厚み
東京精密（株）製のマイクロメーターを用いてシームレスベルトの円周方向２０ｍｍピッチで測定
【０１５２】
・表面抵抗率
表面抵抗率は測定器により好適に測定できる領域が異なるので以下のように使い分けた。測定時間は１０秒とし、エンドレスベルトの円周方向に２０ｍｍピッチで測定した。
【０１５３】

【０１５４】
比較例１
表１の配合で、まず、成形条件Ａで表面抵抗率を１０^９Ω程度に調整してエンドレスベルトを成形した。この表面抵抗率のエンドレスベルトは中間転写ベルトとして好適に用いることができる。
【０１５５】
この比較例１では、Ｔｉ系化合物は配合しなかったので、共重合化、高分子量化の反応は生じなかったと考えられる。得られた成形部材の耐折回数は２８００回であった。また、成形条件Ｂにおいても条件Ａ品とほぼ同物性のエンドレスベルトを得ることができた。
【０１５６】
本比較例のエンドレスベルトを中間転写ベルトとして画像形成装置に搭載したところ、良好な初期画像を得た。さらに連続で画像出力を続けたが、約２万枚出力した時点でエンドレスベルトにクラックが発生し、画像出力ができなくなった。
【０１５７】
本樹脂組成物ペレットは成形条件が多少変化してもベルトの物性があまり変化しないので熱的に安定で扱いやすい意味で好ましい材料といえる。ただし、耐折回数２８００回程度なので、中間転写ベルトとしての初期物性は実用性能を有するが、連続使用によりクラックが発生するので、市場では、交換部品として扱わざるを得ず、物性的には不十分であるといえる。
【０１５８】
比較例２
比較例１の配合を基準とし、Ｔｉ系化合物をＴｉ濃度９８ｐｐｍ配合した。得られたペレットでエンドレスベルトの成形を試みたが、条件Ａ，Ｂどちらにおいてもダイ出口から出てきた樹脂は劣化が激しく、ドローダウンしてしまい、エンドレスベルトを得ることができなかった。
【０１５９】
これは、Ｔｉ系化合物が共重合化と高分子量化と共に、解重合の触媒として作用し、本比較例２の条件のもとでは、解重合の方が優先してしまったためと考えられる。
【０１６０】
比較例３
比較例１を基本配合とし、キレーターとしてのＰ系化合物を０．５重量部配合した。
【０１６１】
この比較例３では、比較例１と同様にＴｉ系化合物を配合しなかったので、共重合化、高分子量化の反応は生じなかったと考えられる。得られた成形部材の耐折回数は３０００回であった。また、成形条件Ｂにおいても条件Ａ品とほぼ同物性のエンドレスベルトを得ることができた。
【０１６２】
ただし、耐折回数が低いので、比較例１と同様に中間転写ベルトとしての初期物性は実用性能を有するが、連続使用によりクラックが発生するので、市場では、交換部品として扱わざるを得ず、物性的には不十分であるといえる。
【０１６３】
実施例１
比較例３の配合を基本とし、さらにＴｉ系化合物をＴｉ濃度６９ｐｐｍ配合した。なお、得られた樹脂の対化学結合質量を前述の方法で測定した結果、１１万ｇ／モルであった。
【０１６４】
その結果、成形条件Ａ，Ｂのいずれでも、良好なエンドレスベルトを得ることができ、特に条件Ａでは、耐折回数は１８，０００回と非常に高い値が得られた。
【０１６５】
本実施例１では、成形条件が変わっても、安定して良好且つ高物性のエンドレスベルトを得ることができた。これは、Ｔｉ系化合物にＰ系化合物が配位したことで、触媒としての反応選択性が高められたため、成形条件が変わっても安定して物性の高いエンドレスベルトが得られるようになったためと考えられる。
【０１６６】
実施例２
実施例１の組成を基準とし、Ｔｉ系化合物及びキレーターとしてのＰ系化合物の配合量をさらに高めた。なお、得られた樹脂の対化学結合質量を前述の方法で測定した結果、１３万ｇ／モルであった。
【０１６７】
これにより、実施例１よりも更に耐折回数の高い良好なエンドレスベルトを安定的に得ることができた。
【０１６８】
本実施例２のエンドレスベルトを中間転写ベルトとして画像形成装置に搭載したところ、良好な初期画像を得た。さらに連続で画像出力を続けたが、画像形成装置の目標寿命となる約１０万枚出力してもエンドレスベルトにクラックが発生することがなかった。また、耐折回数も高く、中間転写ベルトとして使用しても初期物性を満足し、長期にわたり連続使用できるので良好な物性であるといえる。
【０１６９】
実施例３
実施例２の組成を基準とし、カーボンブラック濃度を下げて表面抵抗率１０^１２Ω程度のエンドレスベルトを得た。本エンドレスベルトは搬送転写ベルトとして好適に用いることができる。なお、得られた樹脂の対化学結合質量を前述の方法で測定した結果、１３万ｇ／モルであった。
【０１７０】
実施例４
実施例２の組成を基準とし、カーボンブラック濃度を上げて表面抵抗率１０^４Ω程度のエンドレスベルトを得た。本エンドレスベルトは感光体ベルトの基材として好適に用いることができる。なお、得られた樹脂の対化学結合質量を前述の方法で測定した結果、１３万ｇ／モルであった。
【０１７１】
実施例５
実施例２の組成を基準とし、キレーターとしてＰ系化合物の代わりにヒドラジン類を１重量部配合してエンドレスベルトを得た。なお、得られた樹脂の対化学結合質量を前述の方法で測定した結果、１３万ｇ／モルであった。
【０１７２】
上記実施例３〜５においても、耐折回数の高い良好なエンドレスベルトを安定的に得ることができた。
【０１７３】
【表１】

【０１７４】
【発明の効果】
以上の実施例及び比較例からも明らかな通り、本発明によると、耐屈曲性や耐薬品性及び成形寸法安定性に優れ、溶融混合時の反応による物性劣化を抑えたエンドレスベルト等の成形部材と、このエンドレスベルトを用いた画像形成装置用ベルトと、この画像形成装置用ベルトを用いた画像形成装置が提供される。
【図面の簡単な説明】
【図１】ＰＢＴとＰＣとの混合反応物のＮＭＲチャートである。
【図２】図１のＩＩ部分の拡大図である。
【図３】従来の中間転写装置の側面図である。
【符号の説明】
１ 感光ドラム
２ 帯電器
３ 露光光学系
４ 現像器
５ クリーナー
６ 導電性エンドレスベルト
７，８，９ 搬送ローラ[0001]
BACKGROUND OF THE INVENTION
The present invention uses a molded member having excellent physical properties such as moldability, dimensional accuracy, bending resistance and tensile elongation at break, an endless endless belt having such excellent physical properties, and the endless belt. The present invention relates to an image forming apparatus belt such as an intermediate transfer belt, a conveyance transfer belt, and a photosensitive belt used in an electrophotographic copying machine, a laser beam printer, a facsimile machine, and the like, and an image forming apparatus including the image forming apparatus belt.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an image forming apparatus such as an OA apparatus, an electrophotographic system using a photoconductor and toner, and a toner jet system that directly transfers toner onto an endless belt without using a photoconductor are devised and put on the market. These devices include conductive belts, intermediate transfer belts, transfer transfer belts, transfer separation belts, charging tubes, developing sleeves, fixing belts, toner transfer belts, etc., regardless of the presence or absence of seams, conductive, semiconductive, insulating Endless belts controlled to various electrical resistances are used.
[0003]
For example, the intermediate transfer device is configured to once form a toner image on the intermediate transfer member and then transfer the toner to paper or the like. A conductive endless belt is used for charging and discharging the toner on the surface layer of the intermediate transfer member. The endless belt is set (conductive, semiconductive, insulated) to have different surface resistivity and thickness direction electrical resistance (volume specific resistivity) for each machine model.
[0004]
The transport transfer device is configured to hold the paper once on the transport transfer body, transfer the toner from the photosensitive member onto the paper held on the transport transfer body, and further remove the paper from the transport transfer body by discharging. Has been. On the surface of the transport transfer body, an endless belt with or without a seam is used for charging or neutralizing paper. The endless belt is set to have different surface electric resistance and thickness direction electric resistance (volume specific resistivity) for each machine model as described above.
[0005]
FIG. 3 is a side view of a conventional intermediate transfer apparatus. In the figure, 1 is a photosensitive drum and 6 is a conductive endless belt. 1 is an electrophotographic process unit including a charging device 2, an exposure optical system 3 using a semiconductor laser as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged. The conductive endless belt 6 is wound around the transport rollers 7, 8, and 9 and moves in the direction of the arrow in synchronization with the photosensitive drum rotating in the direction of the arrow.
[0006]
Next, the operation will be described. First, the surface of the photosensitive drum 1 rotating in the direction of arrow A is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device (not shown) is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. This toner image is electrostatically transferred to the conductive endless belt 6 by the electrostatic transfer machine 10 and transferred to the recording paper 11 between the conveying roller 9 and the pressing roller 12.
[0007]
By the way, in the case of a conductive endless belt such as an electrophotographic copying machine, it is functionally driven for a long time by two or more rolls with a high tension, so that sufficient durability is required. Further, when used in an intermediate transfer device or the like, an image is formed with toner on a belt and transferred to paper, and if the belt is loosened or stretched during driving, image misalignment may occur. Further, since toner is transferred electrostatically, a certain degree of conductivity is also required.
[0008]
Such an endless belt is an important part that determines a toner image, and is considered to be one of the three important parts together with the photoreceptor and toner.
[0009]
Therefore, the following items (1) to (7) are required for the intermediate transfer belt.
(1) The semiconductor region has a predetermined surface resistivity and volume specific resistivity.
(2) Toner releasability.
(3) The thickness is thin and uniform.
(4) Strong mechanical strength (hard to break).
(5) There should be little variation in resistance due to the environment (temperature, humidity).
(6) Low cost.
(7) The belt must be seamless and round.
[0010]
In addition, with the recent high-speed printing of machines, the driving speed of the belt has increased, and it has become necessary to improve the durability of the belt.
[0011]
In particular, attention is paid to the fact that printing can be performed at a high speed with a tandem type transport transfer, intermediate transfer belt or toner jet belt in which four photoconductors are arranged, and durability and image misalignment are particularly important.
[0012]
To date, carbon blacks such as acetylene black, furnace black, and channel black are added to resin compositions such as polyamide, polyimide, polyvinylidene fluoride, ethylene tetrafluoroethylene copolymer, polycarbonate, and polyester. Then, by forming this to a thickness of several tens to several hundreds of micrometers, a belt set to a predetermined electrical resistivity (surface resistivity, volume resistivity) is used as an intermediate transfer belt, paper transport and toner transfer. It is known that a transfer belt that also serves as a transfer belt is obtained (Japanese Patent Laid-Open Nos. 63-111267, 5-170946, 6-228335, etc.).
[0013]
In addition, the following methods are considered as a manufacturing method of an endless belt.
[0014]
(I) Rotational molding method (or may be expressed as centrifugal molding method)
Put the resin in which the solution is dissolved on the inner peripheral surface of the cylindrical mold, apply temperature while rotating the mold, volatilize the solvent by half or more, and then remove the seamless tube from the mold. And a step of attaching a seamless tube to the outside of the cylindrical mold and applying a temperature to cause a thermosetting reaction (JP-A-60-170862). This method is mainly used for manufacturing a polyimide transfer belt.
[0015]
(Ii) Extrusion method
In this method, a resin compounded with a conductive substance is melt-extruded in a ring shape. This method is mainly used in a method for producing an ethylenetetrafluoroethylene copolymer, polyvinylidene fluoride, polycarbonate-based, polyester-based, or polyimide-based transfer belt.
[0016]
(Iii) Dipping method
In this method, the resin solution is applied to the outer surface of a cylindrical or columnar mold by dipping or the like to form a fixed thickness, and after heating to form a film, the tubular film formed from the mold is pulled out. This method is mainly used for producing a transfer film made of polyvinylidene fluoride.
[0017]
(Iv) Rubber extrusion molding method
A method has been reported in which polyurethane rubber is extruded and vulcanized into a cylindrical shape, and then surface-polished and coated with a fluororesin or the like on the surface of the outer layer again (Electrophotographic Society Journal 33 (1) 43 (1994)).
[0018]
Conventionally, as such a conductive endless belt, one formed by blending a thermosetting resin or a thermoplastic resin with a conductive material such as carbon black has been mainly used. Among them, those mainly composed of a thermoplastic resin are easy to continuously form and have been widely used. Among the thermoplastic resins, the thermoplastic amorphous resin is more excellent in dimensional accuracy than the thermoplastic crystalline resin. As such an endless belt made of a thermoplastic amorphous resin, for example, a conductive carbon black is blended with a thermoplastic resin such as a polycarbonate resin, and is extruded into a cylindrical film using a cylindrical die. Is known (Japanese Patent Laid-Open No. 3-89357, etc.).
[0019]
However, the thermoplastic amorphous resin has better dimensional accuracy than the thermoplastic crystalline resin, but is inferior in bending resistance. For example, when used in electrophotography as an intermediate transfer belt, cracks are likely to occur during use. .
[0020]
In order to solve this problem, an endless belt in which a polycarbonate and a polyalkylene terephthalate such as polybutylene terephthalate are blended has been proposed (JP-A-4-313757 and JP-A-6-149083).
[0021]
However, polyalkylene terephthalate (hereinafter sometimes referred to as “PAT”) such as polycarbonate (hereinafter sometimes referred to as “PC”) and polybutylene terephthalate (hereinafter sometimes referred to as “PBT”). The endless belt formed by blending has improved bending resistance as compared to the above-mentioned endless belt made of polycarbonate, but the effect of the improvement is still insufficient. Further, since the polyalkylene terephthalate resin has high crystallinity, the dimensional accuracy of the endless belt is lowered when the blending amount is increased.
[0022]
As a general knowledge, thermoplastic resins can be broadly classified into thermoplastic crystalline resins and thermoplastic amorphous resins. Thermoplastic crystalline resins are excellent in bending resistance and chemical resistance but have a large molding shrinkage. Therefore, the dimensional stability is poor and it does not have transparency.Conversely, the thermoplastic amorphous resin is excellent in molding dimensional stability and transparency, but has problems such as poor bending resistance and poor chemical resistance. It has been said that However, in many cases, molded members are required to be excellent in all of bending resistance, chemical resistance, molding dimensional stability, and the like. Various studies have been made on improving physical properties by alloying with crystalline resins, and certain results have been achieved.
[0023]
In these studies, for example, in the field of thermoplastic ester resins, it has been reported that crystalline ester resins and amorphous ester resins can be finely dispersed by promoting transesterification (copolymerization). . However, in the conventional technology, when transesterification (copolymerization) is promoted, generation of a low molecular weight product by depolymerization proceeds, resulting in foaming of the resulting molded member, or molecular chain scission. As a result, there are problems such as lowering of the physical properties of molded parts due to lowering of molecular weight (such as reduction in tensile elongation at break), and fine dispersion of both resins by promoting transesterification has not been put into practical use. .
[0024]
For this reason, the present condition is that the molded member which prevented the physical-property fall by suppressing transesterification reaction is actually used as a practical product.
[0025]
[Problems to be solved by the invention]
As described above, the endless belt made of polycarbonate has poor bending resistance, and there is a problem that the belt is cracked and broken while the belt is driven by a roller.
[0026]
The endless belt made of polyalkylene terephthalate has improved bending resistance compared to the PC belt, but has not yet reached a level that sufficiently satisfies the market needs as an endless belt that can be used until the end of the life of the apparatus.
[0027]
Endless belts made of fluororesins satisfy bending resistance, but have a low Young's modulus of 1000 to 1400 MPa, tend to stretch when tension is applied, cause color misregistration, and are transferred to paper in a deformed state. There were problems that sometimes occurred.
[0028]
The endless belt made of polyimide satisfies the bending resistance, but it cannot be continuously molded because of thermosetting resin, and it is the most expensive among plastics. In addition, because the elastic modulus is high at about 6000 MPa, the motor load is applied when driving the belt, so the thickness must be reduced, or dust can get in between the roller and the belt, or the friction with the photoreceptor. If scratches or the like by cracks entered, cracks were likely to occur and there was a problem in reliability.
[0029]
Endless belts made of rubber have poor toner releasability, and attempts have been made to solve this problem by a method of making this a laminated structure. For this reason, processes such as vulcanization, surface polishing, outer layer fluororesin coating, etc. There are problems such as being complicated, likely to be expensive, and low in elasticity and easy to extend.
[0030]
Further, in an image forming apparatus such as an OA device, electrical characteristics are very important in addition to mechanical properties such as price and bending resistance, and the electrical resistance value must be uniformly controlled within a certain range. For this reason, studies have been made to add various conductive materials such as carbon black and metal oxides. However, if the conductive material is mixed with the resin, it will be affected by the lack of affinity with the resin. There was a problem that the mechanical properties and moldability of the resin would be reduced.
[0031]
As described above, an endless belt that satisfies the mechanical properties represented by the price, the bending resistance, and the electrical properties represented by the electrical resistance has not yet been found.
[0032]
An object of the present invention is to provide a molding member and an endless belt which are excellent in bending resistance, chemical resistance and molding dimensional stability, are inexpensive and suitable as an endless belt, and a belt for an image forming apparatus and an image forming apparatus using the endless belt. A device is provided.
[0033]
[Means for Solving the Problems]
The molded member of the present invention comprises: component A: thermoplastic crystalline ester resin, component B: thermoplastic amorphous ester resin, component C: Ti compound, component D: chelator and component E: conductive material, It is formed after heat-kneading at a blending ratio in which the weight ratio of component A / component B is 1/99 to 99/1 and the weight ratio of Ti element to the total of components A to D is 1 to 10,000 ppm.A molded member, wherein the conductive material is carbon black, and the ratio of component E to the total of components A to E is 1 to 50% by weight.It is characterized by that.
[0034]
That is, as a result of intensive studies to achieve the above object, the present inventors have focused on inexpensive thermoplastic ester resins, and copolymerized thermoplastic crystalline ester resins with thermoplastic amorphous ester resins. When a mixture of a Ti compound as a catalyst for increasing the molecular weight and a chelator for suppressing the reactivity of the Ti compound is heat-kneaded, the transesterification is effected without being affected by the molding conditions. A resin composition that has been copolymerized and high molecular weight by reaction can be stably obtained, and is superior in physical properties such as flex resistance to a resin composition obtained by a conventional technique that suppresses the transesterification reaction. The inventors have found that a molded member having transparency can be obtained depending on the conditions, and therefore that the problem of deterioration of moldability and mechanical properties hardly occurs even when a conductive material is added. It was.
[0035]
In the present invention, as the Ti compound as a catalyst, alkyl titanate is preferable, and the type of chelator as a reaction inhibitor of this Ti compound is not particularly limited, but a P compound is preferable, and among them, particularly preferable , Phosphoric acid, phosphate, phosphoric acid ester, phosphorous acid, phosphite, phosphorous acid ester.
[0036]
Polyesters such as polyalkylene terephthalate (PAT) are used as thermoplastic crystalline ester resins, and polyesters such as polycarbonate (PC) and polyarylate (hereinafter sometimes referred to as “PAr”) are used as thermoplastic amorphous ester resins. Is preferredis there.
[0037]
The endless belt of the present invention comprises such a molded member of the present invention, and in this case, the surface resistivity is 1 to 10.¹⁶It is preferable that for a single endless belt, the maximum value of the resistivity is not more than 100 times the minimum value.
[0038]
The belt for an image forming apparatus of the present invention is an intermediate transfer belt, a conveyance transfer belt, or a photoreceptor belt made of this endless belt.
[0039]
The image forming apparatus of the present invention is provided with this image forming apparatus belt.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
[0041]
First, each compounding component and its compounding ratio in this invention are demonstrated.
[0042]
(Component A: Thermoplastic crystalline ester resin)
The thermoplastic crystalline ester resin used in the present invention is not particularly limited, and may be any thermoplastic resin having an ester skeleton in the main chain or side chain and having crystallinity, and a general-purpose resin should be used. Can do. In addition, the thermoplastic crystalline ester resin used in the present invention refers to a resin having a crystallinity of 10% or more and 100% or less.
[0043]
Specifically, PAT (polyalkylene terephthalate) is preferable among thermoplastic crystalline ester resins, and PBT (polybutylene terephthalate), PET (polyethylene terephthalate), and PEN (polyethylene naphthalate) are more preferable, and PBT is crystalline. Since the rate of crystallization is fast, there is little change in crystallinity due to molding conditions, and it is particularly preferable because the crystallinity is generally stable at around 30%.
[0044]
Moreover, a copolymerization component can also be introduce | transduced into the thermoplastic crystalline ester resin used for this invention in the range which does not impair the effect of this invention remarkably. Specific examples include those having an ester bond as a main chain and an ester bond such as polymethylene glycol introduced therein.
[0045]
The molecular weight of the thermoplastic crystalline ester resin used in the present invention is not particularly limited. For example, a resin having a general molecular weight of about 10,000 to 100,000 can be used. When there is a demand for high mechanical properties, high molecular weight materials are preferred. In this case, the molecular weight is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.
[0046]
(Component B: Thermoplastic amorphous ester resin)
The thermoplastic amorphous ester resin used in the present invention is not particularly limited, and may be any thermoplastic resin that has an ester skeleton in the main chain or side chain and is amorphous, and uses a general-purpose resin. be able to. In addition, the thermoplastic amorphous ester resin used in the present invention refers to one having a crystallinity of less than 10%.
[0047]
Specifically, polyesters such as PC (polycarbonate) and PAr (polyarylate), and resins having ester bonds in the side chains such as PMMA (polymethyl methacrylate) can be mentioned as suitable examples. Of these, polyester is preferable, and particularly PC can be suitably used.
[0048]
Moreover, a copolymerization component can be introduce | transduced in the thermoplastic amorphous ester resin used for this invention in the range which does not impair the effect of this invention remarkably. Specific examples include those in which an ester bond is a main chain and an ester bond such as polymethylene glycol is introduced.
[0049]
There is no particular limitation on the molecular weight of the thermoplastic amorphous ester resin used in the present invention. For example, a resin having a general molecular weight of about 10,000 to 100,000 can be used. When there is a demand for high mechanical properties such as, high molecular weight materials are preferred. In this case, the molecular weight is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.
[0050]
(Weight ratio of thermoplastic crystalline ester resin to thermoplastic amorphous ester resin)
As a compounding ratio in the resin composition of the thermoplastic crystalline ester resin and the thermoplastic amorphous ester resin used in the present invention, a weight ratio of thermoplastic crystalline ester resin / thermoplastic amorphous ester resin is used. A wide range of 1/99 to 99/1 can be employed. However, in general, thermoplastic crystalline ester resins are excellent in chemical resistance and flex resistance, and thermoplastic crystalline ester resins are excellent in molding dimensional stability. It is preferable to set. Especially, the weight ratio of thermoplastic crystalline ester resin / thermoplastic amorphous ester resin is preferably 40/60 to 97/3, more preferably 60/40 to 95/5, and 70/30 to 90 / 10 is particularly preferred.
[0051]
As described above, the ratio of the thermoplastic crystalline ester resin is set as a particularly preferable ratio because the thermoplastic amorphous ester resin is expected to sufficiently improve the molding dimensional stability with a small amount of blending. The reason is that a slight excess of the thermoplastic amorphous ester resin may cause a significant deterioration in chemical resistance such as solvent during coating.
[0052]
(MFR ratio between thermoplastic crystalline ester resin and thermoplastic amorphous ester resin)
If the MFR ratio of both resins is too large, good dispersibility may not be obtained even if the production conditions are adjusted, and uniform dispersion may not be achieved. Therefore, it is preferable that the MFR ratio is small.
[0053]
Specifically, MFR measurement is performed on both resins under the same conditions, and the MFR ratio is preferably in the range of about 1/20 to 20/1, and more preferably in the range of 1/10 to 10/1.
[0054]
Here, as a method for measuring MFR, it is preferable to select a condition close to the processing temperature of the resin in accordance with JIS K-7210.
[0055]
For example, when PBT and PC are selected, it is preferable to set a processing temperature of 260 ° C. as a measurement temperature and compare the MFR ratio of both resins. Moreover, it can measure suitably by selecting 2.16 kg, for example as a load.
[0056]
(Component C; Ti compound)
In the present invention, the Ti compound is used as a catalyst for promoting copolymerization and high molecular weight of a thermoplastic crystalline ester resin and a thermoplastic amorphous ester resin.
[0057]
Although there is no restriction | limiting in particular in this Ti type compound, since an activity is high, an alkyl titanate is preferable and tetrabutyl titanate or tetrakis (2-ethylhexyl) orthotitanate is especially preferable among alkyl titanates. These are easily available as TYZOR TOT (manufactured by DuPont) and TYZOR TBT (manufactured by DuPont).
[0058]
Further, Ti compounds are preferable because they work more effectively when combined with an alkali metal, alkaline earth metal-containing compound, or zinc-containing compound, and it is particularly preferable to use a compound containing Mg element in combination.
[0059]
The compound containing Mg element is not particularly limited, but an organic acid magnesium salt is particularly preferable, and magnesium acetate is particularly preferable.
[0060]
(Ti compound content)
If the amount of the Ti compound in the resin composition is too small, it may not work effectively, so it needs to be increased to some extent, and the weight ratio of the Ti element in the Ti compound is component A, B, C. And 1 ppm or more with respect to the total weight of component D described later, this ratio is more preferably 10 ppm or more, and particularly preferably 20 ppm or more. On the other hand, since ester resins may cause depolymerization in the presence of a large amount of heavy metals, this ratio needs to be reduced to some extent, and the Ti element ratio is 10000 ppm or less, preferably 1000 ppm or less. More preferably, the ratio is 500 ppm or less. Hereinafter, the weight ratio of the Ti element of the Ti-based compound to the total weight of the components A to D may be referred to as “Ti concentration”.
[0061]
Further, when the Ti compound is used in combination with a Mg-containing compound such as magnesium acetate, the amount used is preferably Mg / Ti = 8/2 to 2/8 in terms of the weight concentration ratio of Mg element to Ti element. The degree is most preferred.
[0062]
(Component D; chelator)
In the present invention, if the activity of the polymerization catalyst is too high, the depolymerization of the resin is promoted and mechanical properties are reduced due to a decrease in molecular weight, and foaming associated with the generation of a low molecular weight product may cause problems.
[0063]
Therefore, in the present invention, in order to suppress this depolymerization, a chelator having the ability to coordinate with the metal in the polymerization catalyst, that is, Ti of the Ti-based compound to form a complex is used as the reaction inhibitor.
[0064]
There is no restriction | limiting in particular as a kind of chelator, A well-known chelator can be used.
[0065]
Examples include P-based compounds such as phosphites, phosphates, phosphates, and hydrazines, such as Irgafos 168 (manufactured by Nippon Ciba Geigy Co., Ltd.), PEP36 (Asahi Denka Kogyo Co., Ltd.). ), Sandstub P-EPQ (manufactured by Clariant Japan), phosphite, IRGANOXMD1024 (manufactured by Ciba Geigy Japan), CDA-6 (manufactured by Asahi Denka Kogyo Co., Ltd.) Etc. can be easily obtained from the market. Among these, P-based compounds are most preferable as reaction inhibitors for Ti-based compounds that are catalysts.
[0066]
Hereinafter, the P-based compound as a chelator will be described in detail.
[0067]
Ti-based compounds are effective as a catalyst for copolymerization and high molecular weight, but also promote depolymerization as a side reaction. If the activity is too high, depolymerization may prevail. In the present invention, the P-based compound blended as a chelator coordinates to Ti of the Ti-based compound. Thereby, the reaction regularity as a catalyst becomes high, depolymerization of a side reaction can be suppressed, and copolymerization and high molecular weight can be accelerated | stimulated.
[0068]
Examples of the P-based compound include one or more selected from the group consisting of phosphoric acid, phosphate, phosphate ester, phosphorous acid, phosphite, and phosphite.
[0069]
The phosphate and phosphite are not particularly limited as long as they are metal salts, but alkali metal salts or alkaline earth metal salts are preferable.
[0070]
Examples of the phosphate ester include those represented by the following general formula (I).
[0071]
[Chemical 1]

[0072]
((I) where R¹, R², R³Are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group, Z is a single bond or an oxygen atom, and at least one of them is an oxygen atom. )
[0073]
Specific examples of the phosphate ester include triethyl phosphate, tributyl phosphate, and triphenyl phosphate.
[0074]
Examples of the phosphite include those represented by the following general formulas (II) to (IV).
[0075]
[Chemical 2]

[0076]
((II) where R⁴, R⁵, R⁶Each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group, a cycloalkyl group, an aralkyl group or an alkylaryl group, wherein Z is a single bond or an oxygen atom, and at least one is an oxygen atom. )
[0077]
Specific examples thereof include triethyl phosphite, tributyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, tristearyl phosphite, triphenyl phosphite, tricresyl phosphite, tris (nonylphenyl) phosphine. Phyto, tris (2,4-di-t-butylphenyl) phosphite, decyl-diphenyl phosphite, phenyl-di-2-ethylhexyl phosphite, phenyl-didecyl phosphite, tris (biphenyl) phosphite, tricyclohexyl A phosphite etc. are mentioned.
[0078]
[Chemical 3]

[0079]
((III) where R⁷, R⁸, R⁹, R¹⁰Each independently represents R in formula (II)⁴, R⁵, R⁶Z has the same definition as Z in formula (II). Y represents an alkylene group having 1 to 30 carbon atoms, an arylene group, a cycloalkylene group, an aralkylene group, or an alkylarylene group. )
[0080]
Specific examples thereof include tetraphenyl-4,4′-isopropylidene-diphenol diphosphite, tetratridecyl-4,4′-isopropylidene-diphenol diphosphite, tetratridecyl-4,4′-. Examples include butylidenebis (3-methyl-6-tert-butylphenol) diphosphite, tetrakis (2,4-di-tert-butylphenyl-4,4′-biphenylene) phosphite, and the like.
[0081]
[Formula 4]

[0082]
((IV) where R¹¹Is an alkyl group having 1 to 30 carbon atoms, an aryl group, a cycloalkyl group, an aralkyl group, an alkylaryl group, and R¹²Is an alkylene group having 1 to 20 carbon atoms, and Z has the same definition as Z in formula (II). )
[0083]
Specific examples thereof include bis (stearyl) pentaerythritol diphosphite, bis (2,6-di-t-butylphenyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, and the like.
[0084]
Among the various compounds described above, tributyl phosphite, triphenyl phosphite, bis (stearyl) pentaerythritol diphosphite, and bis (2,6-di-t-butylphenyl) pentaerythritol diphosphite are particularly preferable.
[0085]
(Mixing amount of chelator)
The compounding amount of the chelator in the resin composition is not particularly defined, but if it is small, the addition effect as a reaction inhibitor is hardly exhibited, and the effect is remarkably exerted from the time when the concentration exceeds a certain level. Therefore, in the present invention, the element weight chelating to Ti with respect to the total weight of components A to D is preferably 100 ppm or more, more preferably 300 ppm or more, and particularly preferably 500 ppm or more. In addition, when the compounding amount of the chelator is too large, the catalytic activity of the Ti compound is lost, and a good molded member cannot be obtained. In particular, it is 3000 ppm or less. In the following, the weight ratio of the element chelating to Ti of the chelator relative to the total weight of the components A to D may be referred to as “chelate element concentration”.
[0086]
(Component E: Conductive substance)
As a conductive material,Carbon black with excellent dispersibilityIs used.
[0088]
As the type of carbon black, acetylene black, furnace black, channel black and the like can be suitably used, and among these, acetylene black which has few functional groups as impurities and hardly causes poor appearance due to carbon aggregation can be particularly suitably used. Furthermore, the primary particle diameter is 10 to 100 nm, and the specific surface area is 10 to 200 m.²/ G, those having a pH value of 3 to 11 are more preferred.
[0089]
Moreover, the carbon black to be used may be one type, or two or more types. Furthermore, there is no problem even if carbon black subjected to a known post-treatment process such as carbon black coated with resin, carbon black subjected to graphitization treatment, or carbon black subjected to acid treatment is used as the carbon black.
[0090]
Further, for the purpose of improving the dispersibility of the conductive material, a conductive material such as carbon black treated with a coupling agent such as silane, aluminate, titanate, or zirconate may be used.
[0091]
(Contained amount of conductive material)
As the compounding amount of the conductive substance in the resin composition, the resistance value that is expressed varies depending on the physical properties of the conductive substance to be used. Therefore, it is necessary to set the conductive substance concentration at which the desired resistance value can be obtained. . In the present invention, MatureRatio of carbon black to the total weight of components A to E (hereinafter sometimes referred to as “carbon black concentration”)The1 to 50% by weight,Preferably3-30% by weight,Especially preferably10-25% by weightTheWhen the above range is exceeded, the appearance of the product is deteriorated, and the material strength is lowered, which is not preferable. Moreover, when less than the said range, the effect regarding provision of electroconductivity is small and is not preferable.
[0092]
(Additional ingredients; optional ingredients)
Arbitrary compounding components can be blended in the resin composition constituting the molded member of the present invention in accordance with various purposes.
[0093]
Specifically, antioxidants such as Irganox 1010 (trade name) manufactured by Ciba Geigy Japan, heat stabilizers, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antifogging agents, antiblocking agents. Various additives such as an agent, a slip agent, a crosslinking agent, a crosslinking aid, a colorant, a flame retardant, and a dispersing agent can be added.
[0094]
Furthermore, compounding materials such as various thermoplastic resins, various elastomers, thermosetting resins, and fillers can be blended as the second and third components within a range that does not significantly impair the effects of the present invention.
[0095]
The thermoplastic resin as an additional component is polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component such as ethylene / propylene copolymer Rubber, styrene / butadiene rubber, styrene / butadiene / styrene block copolymer or hydrogenated derivatives thereof, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyimide, liquid crystalline polyester, polysulfone, polyphenylene Sulfide, polybisamidetriazole, polyetherimide, polyetheretherketone, acrylic, polyfluorinated vinylidene, polyfluorinated vinyl, chlorotrifluoroethylene, ethylene Rentetrafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, alkyl acrylate ester copolymer, polyester ester copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer What consists of 1 type, such as a polymer, or these 2 or more types of mixtures can be used.
[0096]
As a thermosetting resin, what consists of 1 type, such as an epoxy resin, a melamine resin, a phenol resin, an unsaturated polyester resin, or these 2 or more types of mixtures can be used, for example.
[0097]
Examples of various fillers include calcium carbonate (heavy and light), talc, mica, silica, alumina, aluminum hydroxide, zeolite, wollastonite, diatomaceous earth, glass fiber, glass beads, bentonite, asbestos, and hollow. Glass ball, graphite, molybdenum disulfide, titanium oxide, carbon fiber, aluminum fiber, styrene steel fiber, brass fiber, aluminum powder, wood powder, rice husk, graphite, metal powder, conductive metal oxide, organometallic compound, organic In addition to fillers such as metal salts, additives such as antioxidants (phenolic, sulfur, phosphate ester, etc.), lubricants, various organic and inorganic pigments, UV inhibitors, antistatic agents, dispersants, neutralization Agents, foaming agents, plasticizers, copper damage inhibitors, flame retardants, crosslinking agents, flowability improvers and the like.
[0098]
Next, the melt-kneading, the molding method, the physical properties of the molded product, the use, etc. in the present invention will be described.
[0099]
(Melt kneading, molding)
In the present invention, the components A to E described above and the above-mentioned additional components added as necessary are heated and kneaded and then molded into a desired shape and solidified to form a molded member. These components are heated and kneaded. Particularly preferred is a method in which a molded member is once molded into a pellet shape, and the pellet is further melt-molded to form a molded member of another shape.
[0100]
In such a melt-kneading process, in the present invention, in order to obtain a good effect by the action of a Ti compound as a polymerization catalyst and a chelator such as a P compound, it is important to set the following conditions: Become.
[0101]
That is, the reactivity when the Ti compound acts as a catalyst has the following characteristics.
[0102]
(1) At low temperatures (melting point of thermoplastic crystalline ester resin to about +40 deg), copolymerization, high molecular weight, and depolymerization are competitive reactions. Quantification is difficult, but copolymerization and high molecular weight are likely to predominate for a short time (approximately 1 to 5 minutes), and depolymerization is predominant for a long time (approximately 5 to 10 minutes or more). There are many.
[0103]
(2) Depolymerization often becomes dominant (regardless of the length of time) under conditions of high temperature (thermoplastic crystalline ester resin melting point +40 deg to +80 deg).
[0104]
For this reason, it is necessary to perform heat-kneading and melt molding at a relatively low temperature. However, if the time is too short, copolymerization and high molecular weight will not proceed, so that high physical properties will not be manifested. Since the polymerization becomes dominant and deteriorates, it is necessary to select the processing conditions while determining the optimum residence time.
[0105]
On the other hand, when a P-based compound is blended as a chelator, for example, the generated Ti—P complex has a slow activity, so the reaction rate of copolymerization and high molecular weight is slow. Compared with the Ti-based compound, the following reactivity is exhibited.
[0106]
{Circle around (1)} At low temperatures (melting point of thermoplastic crystalline ester resin to about +40 deg), copolymerization, high molecular weight, and depolymerization are low in reactivity and are difficult to proceed.
[0107]
(2) At a high temperature (melting point of thermoplastic crystalline ester resin + about 40 deg to +80 deg), in the case of a short time (about 1 to 5 minutes), the reaction of copolymerization and high molecular weight takes precedence, and a long time (about In 5 minutes or more, copolymerization, high molecular weight, and depolymerization often give priority to antagonistic or depolymerized reactions.
[0108]
Therefore, in the present invention, as an example of a suitable processing means, when each component is heat-kneaded and pelletized, the molten state is changed to a high temperature for a short time (for example, the melting point of the thermoplastic crystalline ester resin at the resin temperature +40 to +80 deg. , Preferably about +60 deg; the residence time in the molten state is 0.5 to 5 minutes, preferably about 1 minute), and the reaction of copolymerization and high molecular weight is performed at the stage of heating and kneading. There is no particular limitation on the means for heating and kneading, and a known technique can be used. A twin-screw kneading extruder can be particularly preferably used.
[0109]
Next, this pellet is melt-molded at a low temperature (melting point of thermoplastic crystalline ester resin +0 to +40 deg, preferably about +30 deg) to obtain a molded member. Even when a molded member is obtained in this way, a known technique can be used, and for example, an injection molding machine, an extrusion molding machine, or the like can be used. At such a low temperature, the Ti-P complex hardly promotes depolymerization, and therefore depolymerization does not proceed even if the molding conditions (such as residence time) vary somewhat. Further, since copolymerization and high molecular weight have already been almost completed, high physical properties can be expressed even if the residence time is shortened.
[0110]
In this method, utilizing the characteristics of the reactivity of the Ti-P complex as a catalyst, copolymerization and high molecular weight reaction are promoted at the time of pelletization by heating and kneading. It is important to suppress the reaction of high molecular weight and depolymerization.
[0111]
When the Ti-P complex is heated at 60 to 150 ° C. for about 0.5 to 10 hours, the catalytic ability temporarily increases. Therefore, only the Ti-based compound or the kneaded raw material containing the Ti-based compound before heating and kneading is used. It is also effective to increase the reaction rate of copolymerization and high molecular weight by heating in advance at 60 to 150 ° C. for about 0.5 to 10 hours. The reason why the catalytic ability is increased by prior heating is not clear, but in a normal state, Ti-based compounds have reduced catalytic ability by incorporating water in the air as crystallization water. It is considered that the catalytic ability is increased by removing water.
[0112]
(Chemical bond between thermoplastic crystalline ester resin and thermoplastic amorphous ester resin)
In the present invention, by forming a chemical bond between the molecular chain of the thermoplastic crystalline ester resin and the molecular chain of the thermoplastic amorphous ester resin, the affinity between the two resins is improved and the form is finely dispersed. Therefore, it is possible to obtain a molded member having both the high bending resistance of the thermoplastic crystalline ester resin and the dimensional stability of the thermoplastic amorphous ester resin (and further transparency depending on conditions).
[0113]
There is no particular limitation on the abundance ratio of the chemical bond, but it is basically preferable that the ratio is large. Specifically, it is specifically between the molecular chain of the thermoplastic crystalline ester resin and the molecular chain of the thermoplastic amorphous ester resin. The total mass of thermoplastic crystalline ester resin and thermoplastic amorphous ester resin per mole of chemical bonds (hereinafter, this mass is referred to as “chemical bond mass”) is 1,000,000 g. Is preferably 300 g or less, more preferably 100,000 g or less, and particularly preferably 100,000 g or less.
[0114]
Although there is no restriction | limiting in particular in the measuring method of the quantity of this chemical bond, For example, it can measure by NMR.
[0115]
An example of measurement when PBT is used as the thermoplastic crystalline ester resin and PC is used as the thermoplastic amorphous ester resin is shown below.
Measurement model JEOLGSSX400
Solvent 1,1,1,2,2,2-hexafluoroisopropanol / d-chloroform = 3/7 (volume ratio)
Accumulation count 128 times
Standard TMS
[0116]
By this measurement, the charts shown in FIGS. 2 is an enlarged view of the portion II in FIG.
[0117]
Since the benzene ring hydrogen of terephthalic acid (TPA) has a chemical shift different between bisphenol A (BPA) when carboxylic acid is bonded to butanediol, it binds to TPA and PBT-PC in the PBT molecular chain. A quantitative ratio with TPA can be obtained.
[0118]
(Dispersion form of thermoplastic crystalline ester resin and thermoplastic amorphous ester resin)
In general, it is known that even if two types of thermoplastic resins are melt-mixed, they are not completely mixed and have a sea-island structure. If there is a large difference in the volume fraction between the two thermoplastic resins, the larger the volume fraction is, the smaller the volume fraction is in the sea, and the smaller the volume fraction, the easier it is to form an island structure. Affects the island structure, and it is said that the smaller the melt viscosity is, the easier it is to become the sea, and the larger is the island.
[0119]
In general melt mixing, the dispersed particle size is only about 100 nm, but in the present invention, it is possible to reduce the dispersed particle size to several nanometers or less by optimizing the conditions. The member can be made transparent. Generally, a molded member containing a thermoplastic crystalline ester resin such as PBT is known not to have transparency, but a transparent molded member can also be obtained by using the method according to the present invention.
[0120]
There is no particular limitation on the method for confirming the dispersion state.₄After staining with, a known method such as preparing an ultrathin section and observing with TEM can be used.
[0121]
(Use of the molded member of the present invention)
There is no restriction | limiting in particular in the use of the shaping | molding member of this invention, It can use widely as a structural component of OA equipment, a functional member, a vehicle exterior component, interior material, a structural member of household appliances, a general purpose film, etc.
[0122]
In particular, it can be suitably used in the OA equipment field, which has strict physical properties such as dimensional accuracy, bending resistance, and tensile elongation at break, especially for functional members. When used as an intermediate transfer belt, a transfer transfer belt, a photoreceptor belt or the like in an image forming apparatus such as a printer, it is preferable because there are few problems such as cracking and elongation.
[0123]
Below, the endless belt as an example of the suitable usage example of the shaping | molding member of this invention is demonstrated.
[0124]
(Endless belt)
In order to obtain the endless belt of the present invention, the above-described components A to E and other additional components blended as necessary are mixed by, for example, a twin-screw kneading extruder and pelletized to become an endless belt. The molding method is particularly preferably used.
[0125]
The molding method is not particularly limited, and can be obtained by employing a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, or an inflation molding method. This is a continuous melt extrusion method. In particular, the internal cooling mandrel method or vacuum sizing method of the downward extrusion method capable of controlling the inner diameter of the extruded tube with high accuracy is preferable, and the internal cooling mandrel method is most preferable.
[0126]
In addition, an endless belt having better physical properties can be obtained by optimizing the temperature and residence time at the time of molding, so it is preferable to adjust the conditions according to each formulation.
[0127]
(Physical properties of endless belt)
According to the present invention, an endless belt having the following physical properties can be obtained.
[0128]
・ Folding resistance
When the endless belt of the present invention is used in an image forming apparatus as an intermediate transfer belt, for example, an endless belt having good bending resistance is preferred because cracks occur and images cannot be obtained if the bending resistance is poor.
[0129]
The degree of bending resistance can be quantitatively evaluated by following the method for measuring the folding endurance of JIS P-8115, and it is judged that an endless belt with a higher folding endurance is less susceptible to cracking and has superior bending resistance. be able to.
[0130]
As a specific numerical value, if it is 500 times or more, it can be used by exhibiting the function as an endless belt, but it is practically 5000 times or more, more preferably 10,000 times or more, and more preferably 30000. If it is more than the number of times, it is particularly preferable because cracks are hardly generated.
[0131]
・ Tensile modulus
If the tensile elastic modulus of the endless belt is low, for example, when it is used in an image forming apparatus as an intermediate transfer belt, a slight elongation may occur due to the tension, which may cause problems such as color misregistration. More specifically, it is preferably 1000 MPa or more, more preferably 1500 MPa or more, further preferably 2000 MPa or more, and particularly preferably 2500 MPa or more, since problems such as color misregistration can be significantly suppressed.
[0132]
In general, a soft plastic has a high folding resistance but tends to have a low tensile elastic modulus. Conversely, a hard plastic can obtain a high tensile elastic modulus but tends to become brittle and often has only a low folding resistance. In this invention, it can be said that it is useful in the meaning which can obtain a high frequency | count of folding-proof, maintaining the characteristic of the inherent high tensile elasticity modulus which PBT and PC have.
[0133]
・ Surface resistivity
In the endless belt of the present invention, conductivity is obtained by blending a conductive material, preferably carbon black. The resistance region of the endless belt varies depending on the purpose, but the surface resistivity is 1 to 1 × 10¹⁶It is preferable to select from the range of Ω.
[0134]
Although the more preferable range of the surface resistivity varies depending on the application, for example, when used as a photoreceptor belt, 1 to 1 × 10 10 so that the charge on the outer surface can be released to the inner surface as necessary.⁶A low surface resistivity of Ω is preferable, and when used as an intermediate transfer belt, 1 × 10 can be easily charged and transferred.⁶~ 1x10¹¹Ω is preferable, and when used as a conveyance transfer belt, it is easily charged and is not easily damaged even at a high voltage.¹⁰~ 1x10¹⁶A high region such as Ω is preferable.
[0135]
Further, it is preferable that the distribution of the surface resistivity in one endless belt is narrow, and in each preferable surface resistivity region, the maximum value in one belt is preferably within 100 times the minimum value, and within 10 times. It is particularly preferred that
[0136]
The surface resistivity of the endless belt can be easily measured by, for example, Hiresta, Loresta manufactured by Dia Instruments Co., Ltd. or R8340A manufactured by Advantest Co., Ltd.
[0137]
・ Endless belt thickness
The thickness of the endless belt is preferably 50 to 1000 μm, more preferably 80 to 500 μm, and particularly preferably 100 to 200 μm.
[0138]
(Use of endless belt)
When the endless belt of the present invention is used as an intermediate transfer belt, a transfer transfer belt, a photoreceptor belt or the like in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, or a facsimile machine, there are few problems such as cracking and elongation, It can be used stably over a long period of time.
[0139]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
[0140]
In the following Examples and Comparative Examples, endless belts were produced with the following raw materials and molding conditions, evaluated, and the results are shown in Table 1.
[0141]
(material)
The raw materials were as follows, and the mixing ratio was as shown in Table 1.
Component A: PBT (weight average molecular weight 40,000; PS-converted weight average molecular weight 122,000)
Component B: PC (weight average molecular weight 28,000; PS-converted weight average molecular weight 64,000)
Component C: Ti-based compound (titanium (IV) butoxide)
Component D: P-based compound (sand stub P-EPQ: tetrakis (2,4-ditertiary butylphenol)
) 4,4'-biphenylylene diphosphonite (structural formula is as follows); manufactured by Clariant Japan Co., Ltd.)
Or hydrazines (IRGANOX MD1024; manufactured by Ciba Geigy Japan Ltd.)
[0142]
[Chemical formula 5]

[0143]
Component E: Carbon black (Denka Black; manufactured by Electrochemical Co., Ltd.)
[0144]
In addition, about the component A and the component B, MFR (260 degreeC 2.16kg) measured by the above-mentioned method is respectively component A: 7g / 10min and component B: 3g / 10min, The MFR ratio of both resin is 2.33. / 1.
[0145]
(Heat kneading)
Each raw material was pelletized with a resin composition using a twin-screw kneading extruder (PMT32 manufactured by IKG Corporation). The thermoplastic resin was dried at 130 ° C. for 8 hours before kneading and further cooled to about 60 ° C. before being used for kneading. The kneading conditions were a kneader set temperature of 240 ° C., a screw rotation speed of 100 rpm, and a discharge speed of 15 g / h. The residence time in the melted state in the kneader under these conditions is about 2 minutes on average.
[0146]
(Endless belt molding method)
This material pellet was dried at 130 ° C. for 8 hours, extruded in a molten tube state below the annular die by a 40 mmφ extruder with a 6-thread spiral annular die having a diameter φ of 180 mm and a lip width of 1 mm. The cooling mandrel with an outer diameter of 170 mm mounted on the same axis via a support rod is brought into contact with the outer surface of the cooling mandrel to be cooled and solidified. With a roll, the seamless belt is drawn in a cylindrical shape, and is cut into a length of 340 mm, and the extrusion amount and take-up speed are adjusted so that the following thickness and residence time are obtained. A belt. In addition, in order to evaluate the residence time dependency of the physical properties of the endless belt, the residence time was adjusted and molded under the following two conditions.
[0147]
Condition A: Retention time of 12 minutes and thickness of 150 μm are targeted, and the thickness range is adjusted to ± 15 μm and molded
Condition B: Targeting a residence time of 24 minutes and a thickness of 150 μm, adjusting the thickness range to ± 15 μm and forming
[0148]
Under this condition B, molding was performed by slowing the screw rotation so that the residence time was longer than in condition A, and the take-up speed was also adjusted so that the belt thickness was the same as that in condition A.
[0149]
(Evaluation)
The evaluation was carried out by cutting the endless belt into an appropriate size as necessary.
[0150]
・ Folding resistance
JIS P-8115 compliant
Each sample was measured three times, and the average value (2 significant digits) was taken as the representative value. The number of folding resistances is an index of bending fatigue resistance, and the larger the number, the harder it is to break and the stronger it is.
[0151]
・ Thickness
Measured with a 20 mm pitch in the circumferential direction of the seamless belt using a micrometer manufactured by Tokyo Seimitsu Co., Ltd.
[0152]
・ Surface resistivity
The surface resistivity can be properly measured depending on the measuring instrument. The measurement time was 10 seconds, and the measurement was performed at a pitch of 20 mm in the circumferential direction of the endless belt.
[0153]

[0154]
Comparative Example 1
First, the surface resistivity is 10 under the molding condition A with the composition shown in Table 1.⁹An endless belt was formed by adjusting to about Ω. This endless belt having a surface resistivity can be suitably used as an intermediate transfer belt.
[0155]
In Comparative Example 1, since no Ti-based compound was blended, it is considered that no copolymerization or high molecular weight reaction occurred. The obtained molded member had a folding endurance of 2800 times. Also, under the molding condition B, an endless belt having substantially the same physical properties as the condition A product could be obtained.
[0156]
When the endless belt of this comparative example was mounted on an image forming apparatus as an intermediate transfer belt, a good initial image was obtained. Further, the image output was continued continuously. However, when about 20,000 sheets were output, a crack occurred in the endless belt, making it impossible to output the image.
[0157]
The resin composition pellets can be said to be a preferred material in terms of being thermally stable and easy to handle because the physical properties of the belt do not change much even if the molding conditions change somewhat. However, since the number of folding times is about 2,800, the initial physical properties as an intermediate transfer belt have practical performance, but cracks occur due to continuous use, so they must be handled as replacement parts in the market and are not physically good. That's enough.
[0158]
Comparative Example 2
Based on the formulation of Comparative Example 1, a Ti compound was blended with a Ti concentration of 98 ppm. Attempts were made to mold an endless belt with the obtained pellets, but the resin exiting from the die exit was severely deteriorated in both conditions A and B, and the resin was drawn down, so that an endless belt could not be obtained.
[0159]
This is presumably because the Ti-based compound acts as a catalyst for depolymerization along with copolymerization and high molecular weight, and the depolymerization has been prioritized under the conditions of this Comparative Example 2.
[0160]
Comparative Example 3
Comparative Example 1 was used as a basic blend, and 0.5 part by weight of a P-based compound as a chelator was blended.
[0161]
In Comparative Example 3, it was considered that the reaction of copolymerization and high molecular weight did not occur because no Ti-based compound was blended as in Comparative Example 1. The resulting molded member had a folding endurance of 3000 times. Also, under the molding condition B, an endless belt having substantially the same physical properties as the condition A product could be obtained.
[0162]
However, since the number of folding times is low, the initial physical properties of the intermediate transfer belt as in Comparative Example 1 have practical performance, but since cracks occur due to continuous use, they must be handled as replacement parts in the market. It can be said that the physical properties are insufficient.
[0163]
Example 1
Based on the formulation of Comparative Example 3, a Ti compound was further blended with a Ti concentration of 69 ppm. In addition, it was 110,000 g / mol as a result of measuring the chemical bond mass of the obtained resin by the above-mentioned method.
[0164]
As a result, a good endless belt can be obtained under both molding conditions A and B. In particular, under condition A, a very high value of 18,000 folding times was obtained.
[0165]
In Example 1, an endless belt having stable and good physical properties could be obtained even when the molding conditions were changed. This is because the P-based compound is coordinated to the Ti-based compound, so that the reaction selectivity as a catalyst is enhanced, and thus an endless belt having high physical properties can be stably obtained even if the molding conditions are changed. Conceivable.
[0166]
Example 2
Based on the composition of Example 1, the compounding amount of the Ti compound and the P compound as the chelator was further increased. In addition, as a result of measuring the chemical bond mass of the obtained resin by the above-mentioned method, it was 130,000 g / mol.
[0167]
As a result, a good endless belt having a higher folding resistance than that of Example 1 could be stably obtained.
[0168]
When the endless belt of Example 2 was mounted on an image forming apparatus as an intermediate transfer belt, a good initial image was obtained. Further, the image output was continued continuously, but no crack was generated in the endless belt even when about 100,000 sheets were output, which is the target life of the image forming apparatus. Further, the folding performance is high, and even if it is used as an intermediate transfer belt, it satisfies the initial physical properties and can be said to have good physical properties because it can be used continuously for a long time.
[0169]
Example 3
Using the composition of Example 2 as a reference, the surface resistivity is 10 by decreasing the carbon black concentration.¹²An endless belt of about Ω was obtained. This endless belt can be suitably used as a conveyance transfer belt. In addition, as a result of measuring the chemical bond mass of the obtained resin by the above-mentioned method, it was 130,000 g / mol.
[0170]
Example 4
Based on the composition of Example 2, the surface resistivity was increased by increasing the carbon black concentration.⁴An endless belt of about Ω was obtained. This endless belt can be suitably used as a base material for a photoreceptor belt. In addition, as a result of measuring the chemical bond mass of the obtained resin by the above-mentioned method, it was 130,000 g / mol.
[0171]
Example 5
Based on the composition of Example 2, 1 part by weight of hydrazine was used as a chelator instead of P-based compound to obtain an endless belt. In addition, as a result of measuring the chemical bond mass of the obtained resin by the above-mentioned method, it was 130,000 g / mol.
[0172]
Also in Examples 3 to 5, a good endless belt having a high folding resistance could be stably obtained.
[0173]
[Table 1]

[0174]
【The invention's effect】
As is apparent from the above examples and comparative examples, according to the present invention, a molded member such as an endless belt that has excellent bending resistance, chemical resistance, and molding dimensional stability, and suppresses deterioration of physical properties due to reaction during melt mixing. And an image forming apparatus belt using the endless belt, and an image forming apparatus using the image forming apparatus belt.
[Brief description of the drawings]
FIG. 1 is an NMR chart of a mixed reaction product of PBT and PC.
FIG. 2 is an enlarged view of a portion II in FIG.
FIG. 3 is a side view of a conventional intermediate transfer apparatus.
[Explanation of symbols]
1 Photosensitive drum
2 Charger
3 Exposure optical system
4 Developer
5 Cleaner
6 Conductive endless belt
7, 8, 9 Transport roller

Claims (8)

Component A: thermoplastic crystalline ester resin,
Component B: thermoplastic amorphous ester resin,
Component C: Ti compound,
Component D; chelator and component E; conductive material,
The weight ratio of component A / component B is 1/99 to 99/1,
The weight ratio of Ti element to the total of components A to D is 1 to 10,000 ppm.
A molded member formed by heating and kneading at a blending ratio of
The molded member, wherein the conductive material is carbon black, and the ratio of the component E to the total of the components A to E is 1 to 50% by weight . The molded member according to claim 1, wherein the chelator is a P-based compound. 3. The Ti compound according to claim 2, wherein the Ti compound is an alkyl titanate, and the P compound is selected from the group consisting of phosphoric acid, phosphate, phosphate ester, phosphorous acid, phosphite, and phosphite ester. 1 type or 2 types or more, The shaping | molding member characterized by the above-mentioned. 4. The molded member according to claim 1, wherein the thermoplastic crystalline ester resin is polyalkylene terephthalate, and the thermoplastic amorphous ester resin is polycarbonate or polyarylate. . An endless belt comprising the molded member according to any one of claims 1 to 4 . 6. The endless device according to claim 5, wherein the surface resistivity is 1 to 1 × 10 ¹⁶ Ω, and in one endless belt, the maximum value of the resistivity is not more than 100 times the minimum value. belt. An intermediate transfer belt for an image forming apparatus comprising an endless belt according to claim 5 or 6, the conveying transfer belt, or the image forming apparatus belt is a photoreceptor belt. An image forming apparatus comprising the belt for an image forming apparatus according to claim 7 .

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