JP2004122699A - Release film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release film excellent in heat resistance, not to cause deterioration in flatness, excellent also in oligomer deposition-inhibiting property, even when subjected to a heat treatment at a high temperature in a processing step for applying it to various uses, further excellent in processing properties in sticking, slit/cutting or the like, and applicable to various uses. <P>SOLUTION: The release film comprises a substrate film composed of a resin composition containing polyester and polyimide, having a release layer formed on at least one surface of the substrate film. <P>COPYRIGHT: (C)2004,JPO

Description

【００４９】
このようなフッ素含有樹脂としては、例えば、フッ素含有ビニル重合性単量体からなる重合体（オリゴマーを含む）または共重合体、またはフッ素含有ビニル重合性単量体とフッ素原子を含有しないビニル重合性単量体の少なくとも１種との共重合体、または、これらの混合物であってフッ素原子を５〜８０モル％有するものがあげられる。
【００５０】
フッ素含有ビニル重合性単量体からなる重合体としては、具体例として、ポリ［２−（パーフルオロノネニルオキシ）エチルメタクリレート］、ポリ［２−（パーフルオロノネニルオキシ）エチルアクリレート］、ポリ［２−（パーフルオロノネニルオキシベンゾイルオキシ）エチルメタクリレート］、ポリ［２−（パーフルオロノネニルオキシベンゾイルオキシ）エチルアクリレート］、ポリ［２、２、２−トリフルオロエチルメタクリレート］、ポリ［２、２、２−トリフルオロエチルアクリレート］、ポリ［２、２、３、３、３−ペンタフルオロプロピルメタクリレート］、ポリ［１−メチル−２、２、３、３、４、４−アクリル酸、ヘキサフルオロブチルメタクリレート］、ポリ［１−メチル−２、２アクリル酸、３、３、４、４、−ヘキサフルオロブチルアクリレート］、ポリ［パーフルオロヘプチルエチルメタクリレート］、ポリ［パーフルオロヘプチルエチルアクリレート］、ポリ［パーフルオロヘプチルビニルエーテル］、ポリ［α、β、β−トリフルオロスチレン］、ポリフッ化ビニリデン、ポリヘキサフルオロプロピレン、ポリテトラフルオロエチレンなどがあげられる。この中で、特に基材フィルムに対する親和性などの点から、ポリ［パーフルオロメタクリレート］、ポリ［パーフルオロアクリレート］が好ましい。
【００５１】
前記フッ素含有ビニル重合性単量体と共重合するフッ素原子を含有しないビニル重合性単量体としては、炭化水素系ビニル重合性単量体、炭化水素系非共役ジビニル重合性単量体、官能基含有ビニル重合性単量体、などの化合物があげられ、炭化水素系ビニル重合性単量体としては、例えば、アクリル酸メチル、アクリル酸プロピル、アクリル酸ブチル、アクリル酸イソアミル、アクリル酸２−エチルヘキシル、アクリル酸オクチル、アクリル酸オクタデシル、アクリル酸ラウリル、アクリル酸セシル、アクリル酸Ｎ，Ｎ−ジエチルアミノエチル、メタクリル酸メチル、メタクリル酸プロピル、メタクリル酸ブチル、メタクリル酸イソアミル、メタクリル酸２−エチルヘキシル、メタクリル酸オクチル、メタクリル酸オクタデシル、メタクリル酸ラウリル、メタクリル酸セシル、メタクリル酸Ｎ，Ｎ−ジエチルアミノエチル、酢酸ビニル、プロピオン酸ビニル、カプリン酸ビニル、ラウリン酸ビニル、ステアリン酸ビニル、スチレン、α−メチルスチレン、ｐ−メチルスチレン、フッ化ビニル、塩化ビニル、臭化ビニル、フッ化ビニリデン、塩化ビニリデン、ヘプタン酸アリル、酢酸アリル、カプリン酸アリル、カプロン酸アリル、ビニルメチルケトン、ビニルエチルケトン、１、３−ブタジエン、２−クロロ−１、３−ブタジエン、２、３−ジクロロ−１、３−ブタジエン、イソプレンなど、炭化水素系非共役ジビニル共重合体としては、例えば、エチレングリコールジアクリレート、エチレングリコールメタクリレート、プロピレングリコールジアクリレート、ジエチレングリコールジアクリレート、ジエチレングリコールジアクリレート、ジエチレングリコールジメタクリレート、ポリエチレングリコールジアクリレート、ポリエチレングリコールジメタクリレート、ジビニルベンゼン、ビニルアクリレート、ジブロムネオペンチルグリコールジメタクリレートなど、官能基含有ビニル共重合性単量体としては、例えば、アクリル酸、メタクリル酸、アクリルアミド、メタクリルアミド、Ｎ−ブトキシメチルアクリルアミド、Ｎ−ブトキシメチルアクリルアミド、ダイアセトンアクリルアミド、メチロールダイアセトンアクリルアミド、２−ヒドロキシエチルメタクリレート、２−ヒドロキシエチルアクリレート、ヒドロキシプロピルアクリレート、３−クロロ−２−ヒドロキシプロピルメタクリレートなどがあげられ、これらの中から選択されるが特に限定されるものではない。
【００５２】
フッ素含有樹脂とフッ素系オイルを主成分とするものとして用いられるフッ素系オイルとしては、代表的なものとしてパーフルオロポリエーテル完全フッ素化油等があげられ、具体的には、例えば、下記の化学式等で表される化合物を主成分とするものである。
【００５３】
【化２】

【００５４】
【化３】

【００５５】
【化４】

【００５６】
【化５】

【００５７】
【化６】

【００５８】
中でも本発明では、剥離性の点で化学式化２で表される化合物が好適である。
【００５９】
また、共重合量は前記フッ素含有樹脂とフッ素系オイルを主成分とする離型層が基材フィルムの少なくとも片側に塗布されるが、フッ素含有樹脂とフッ素系オイルの溶媒としては、例えば、アルコール系、カルボン酸エステル系、ケトン系、脂肪族炭化水素脂環式または芳香族炭化水素系、ハロゲン化炭化水素系、フッ素系およびこれらの混合系があげられる。
【００６０】
ワックスとしては、公知の各種ワックスを使用することができる。例えば石油系ワックス、植物系ワックス、鉱物系ワックス、動物系ワックス、低分子量ポリオレフィン類などを使用することができ特に限定されるものではないが、石油系ワックス、植物系ワックスが特に好ましく使用される。石油系ワックスとしてはパラフィンワックス、マイクロクリスタリンワックス、酸化ワックスなどがあげられる。また植物系ワックスとしてはキャンデリラワックス、カルナウバワックス、木ロウ、オリキューリーワックス、さとうきびロウ、ロジン変性ワックスなどがあげられる。それらの中でも、下記組成物から成るものが特に好ましい。すなわち｛ロジンまたは不均化ロジン、または水添ロジン・α、β置換エチレン（α置換基：カルボキシル、β置換基：水素またはメチルまたはカルボキシル）付加物］・アルキルまたはアルケニル（各炭素数１〜８）ポリ（繰り返し単位：１〜６）アルコールのエステル付加物を用いるのが離型性や滑り性の点で好ましく、さらに上記酸化ワックスとの混合系で用いるとより好ましい。
【００６１】
本発明のワックスを主成分とする離型層には、さらにオイル状物質を加えると高温での離型性が優れたものにすることができる。ここでオイル状物質とは常温で液体あるいはペースト状のオイルであり、植物油、油脂、鉱物油、合成潤滑油などやこれらの混合物をあげることができる。これらの中でも、高温での離型性の良好な鉱物油、合成潤滑油が好適である。該オイル状物質は前記ワックス系組成物１００重量部が好ましく、さらに好ましくは３〜５０重量部添加するのが好ましい。
【００６２】
さらに、本発明の離型層には、本発明の目的を損なわない範囲で公知の添加剤、例えば、消泡剤、塗布性改良剤、増粘剤、帯電防止剤、酸化防止剤、紫外線吸収剤、硬化剤、染料等を含有せしめても良いし、滑剤として無機または有機化合物からなる微細粒子を含有せしめてもよい。
【００６３】
本発明において形成される離型層の厚みは、好ましくは０．０１〜２０μｍ、より好ましくは０．０２〜１５μｍ、さらにより好ましくは０．０５〜１３μｍである。離型層の厚みが０．０１μｍ未満であると塗布層の厚さ斑が生じて離型性能を大きく左右するため所望の離型性能が得られない部分が生じるおそれがある。逆に２０μｍを超えると塗膜の乾燥及び硬化に長時間要し生産上不都合になったり、離型剤材料が多量に必要になるばかりか、離型層自体が脆くなるおそれがある。
【００６４】
次に、本発明の離型フィルムの製造方法の具体例について説明するが、以下の記述に限定されものではない。
【００６５】
まず、基材フィルムとして、ポリエチレンテレフタレートを用い、ポリイミドとして、ポリエーテルイミドを用いた例を示す。ポリエーテルイミドは特に限定されるものではないが、例えば、“ウルテム”（Ｇｅｎｅｒａｌ　　Ｅｌｅｃｔｒｉｃ社製）を用いることができる。
【００６６】
まず、常法に従い、テレフタル酸とエチレングリコールとをエステル化し、または、テレフタル酸ジメチルとエチレングリコールをエステル交換反応することにより、ビスーβ―ヒドロキシエチルテレフタレート（ＢＨＴ）を得る。次にこのＢＨＴを重合槽に移送しながら、真空下で２８０℃に加熱して重合する。この時、所定量のポリエーテルイミドを添加しておいてもよい。必要に応じて、得られたポリエステルペレットを減圧下で固相重合する。固相重合する場合は、あらかじめ１８０℃以下の温度で予備結晶化させた後、１９０〜２５０℃で１ｍｍＨｇ程度の減圧下、３〜５０時間固相重合させ、固有粘度０．５〜１．５（ｄｌ／ｇ）のペレットを作る。
【００６７】
また、公知の方法で重合したポリエチレンテレフタレートのペレットとポリエーテルイミドのペレットとを任意の割合で混合して、２７０〜３００℃に加熱されたベント式２軸混練押出機に供給して溶融押出し、両者を混練する。滞留時間は０．５〜２０分が好ましく、より好ましくは１〜１５分の条件である。また、必要に応じて、得られたチップを再び二軸押出機に投入し相溶するまで押出を繰り返してもよい。上記混練によって、ポリエチレンテレフタレートとポリエーテルイミドとは相溶し、ガラス転移点が単一の混合ポリエステルのペレットを得ることができる。
【００６８】
基材フィルム中に粒子を含有させる場合は、ポリエステル中に含有させることがポリエステルとポリイミドの均一相溶性の点から好ましい。エチレングリコールに所定割合の粒子をスラリーの形で添加して分散させた後、このエチレングリコールをテレフタル酸と重合させる方法が好ましい。粒子を添加する際には、例えば、粒子の合成時に得られる水ゾルやアルコールゾルを一旦乾燥させることなく添加すると粒子の分散性がよい。また、粒子の水スラリーを直接所定のポリエステルペレットと混合し、ベント式２軸混練押出機を用いて、ポリエステルに練り込む方法も有効である。
【００６９】
ポリエーテルイミドあるいは粒子の含有量を調節する方法としては、上記方法で作ったポリエーテルイミドを高濃度で含有するペレット、あるいは粒子を高濃度に含有するＰＥＴマスタ−ペレットを作っておき、それを製膜する時に粒子を実質的に含有しないポリエステルペレットで希釈して、それぞれの含有量を調節する方法が有効である。
【００７０】
次に、これらのポリエステル、ポリエーテルイミド、さらには粒子を含有するペレット、または、そのブレンドしたペレットを、１１０〜１９０℃で３時間以上真空乾燥した後、押出機でスリット状口金から溶融押出し、２０〜６０℃のキャスティングドラム上で冷却固化せしめて未延伸フィルムを作る。この場合、溶融ポリマー中の異物や変質ポリマーを除去するために各種のフィルター、例えば、焼結金属、多孔性セラミック、サンド、金網などの素材からなるフィルターを用いることが好ましい。また、必要に応じて、それぞれのポリマー流路にスタティックミキサー、ギヤポンプを設置し、ポリマ押出量を制御する方法は本発明の効果を得るのに有効である。
【００７１】
基材フィルムの構成を例えば２層積層構成（Ａ層／Ｂ層）とする場合は、２台の押出機で積層用マニホールド又は矩形の合流ブロックを用いて、上述と同様に溶融押出し積層未延伸フィルムを得る。この場合ポリエステルＡ層とＢ層を構成する各ポリマーの固有粘度の差（絶対値）を０〜１．２（ｄｌ／ｇ）、好ましくは０〜１（ｄｌ／ｇ）の範囲にしておくことが、本発明の基材フィルムを安定して工業的に製造するのに有効である。また該未延伸フィルムにおいて、溶融状態のポリマーを口金から押し出す場合のドラフト比（＝口金リップポリマ流速／キャスティングドラム上のフィルム（ポリマ）流速）は５〜３０とすることが、本発明のフィルムを得る上で好ましい。
【００７２】
次にこの未延伸フィルムを、最初に長手方向に延伸する。長手方向の延伸は通常ロールを用いて行われるが、延伸温度は８０〜１８０℃、好ましくは９０〜１６０℃である。長手方向の延伸は、１段もしくは２段階以上の多段階で行い、２〜８倍、好ましくは２．５〜６倍の範囲で延伸することが好ましい。
【００７３】
その後フィルムの両端をクリップで把持しつつテンターに導く。テンター内で予熱後、幅方向に２．５〜８倍、好ましくは３〜６倍で、延伸速度３０００〜３００００％／分の範囲で延伸を行う。幅方向に延伸した基材フィルムは、更に熱処理を行う。延伸温度を８０〜１６０℃、好ましくは９０〜１５０℃、熱処理温度を１８５〜２４５℃程度とするのが好ましい。必要以上に熱処理温度を高くすると結晶配向が崩れて平面性の悪化や剛性の低下を招きやすいので、少なくともポリエステルの融点よりも１０℃、好ましくは２０℃低い温度以下で、１〜２０秒間で行うことがよい。また、上記の熱処理だけでは熱収縮が残留しているため、フィルムの歪みが除去しきない場合は、必要に応じて、長手方向及び幅方向に、弛緩しながら熱固定またはフィルムを冷やしながら巻き取る。弛緩率は０．５〜１０％以下の場合に、平面性を維持し、熱寸法安定性に優れたフィルムを得るのに有効である。
【００７４】
次に、上記の方法により得られた基材フィルムに離型層を塗布する。なお、基材フィルムの表面に離型層を設ける時期は、特に限定されない。基材フィルムの製造工程中に塗布する方法、または、ロール状に巻き取った基材フィルムを塗布専用のコーターを用いて塗布する方法のいずれでも良い。塗布の方法としては特に限定されないが、リバースロールコート、ワイヤーバーコート、ドクターブレード、グラビアロールコート、エアーナイフコート、ロッドコート、ダイコート、スプレーコート、含浸コート等を単独または組み合わせて適用することができる。
（物性の測定方法ならびに効果の評価方法）
本発明における特性値の測定方法並びに効果の評価方法は次の通りである。
【００７５】
（１）基材フィルムの積層厚さ及び離型層厚さ
透過型電子顕微鏡（日立製Ｈ−６００型）を用いて、加速電圧１００ｋＶで、フィルム断面を、超薄切片法（ＲｕＯ_４染色）で観察し、積層界面をＴＥＭ写真のコントラストの濃淡差でとらえる。隣接する層の一方がポリイミドまたは粒子を含有する場合は、ポリイミドや粒子の有無や粒子の形状の違いから、各層の界面をとらえ、その積層厚さ及び離型層厚さを求める。
【００７６】
また、倍率は、判定したい積層厚さによって選ぶことが通常であり、特に限定されないが、１万〜２０万倍が適当である。
【００７７】
（２）ポリイミドの含有量
ポリエステルとポリイミドの両者を溶解する適切な溶媒に溶解し、^１Ｈ核のＮＭＲ（核磁気共鳴）スペクトルを測定する。得られたスペクトルで、ポリエステル中の芳香族プロトンに相当する吸収（ＰＥＴでは８．１ｐｐｍ付近）とポリイミドのプロトンに相当する吸収のピーク面積強度をもとめ、その比率とプロトン数よりブレンドのモル比を算出する。さらにポリマーの単位ユニットに相当する式量より重量比を算出する。
【００７８】
ポリイミドがポリエーテルイミド（ＰＥＩ）の場合、フィルムをヘキサフルオロイソプロパノール／クロロホルムのようなＰＥＴとＰＥＩの両者を溶解する適切な溶媒に溶解し、^１Ｈ核のＮＭＲスペクトルを測定する。得られたスペクトルで、ポリエステル中の芳香族プロトンに相当する吸収（ＰＥＴでは８．１ｐｐｍ付近）とポリエーテルイミドのビスフェノールＡの芳香族のプロトンに相当する吸収（７．０ｐｐｍ）のピーク面積強度をもとめ、その比率とプロトン数よりブレンドのモル比を算出する。さらにポリマーの単位ユニットに相当する式量より重量比を算出する。
【００７９】
１）ＮＭＲ測定条件
装置　　　　　　：ＢＲＵＫＥＲ　ＤＲＸ−５００（ブルカー社製）
溶媒　　　　　　：ヘキサフルオロイソプロパノール／重クロロホルム
観測周波数　　　：４９９．８ＭＨｚ
基準　　　　　　：ＴＭＳ（０ｐｐｍ）
測定温度　　　　：３０℃
観測幅　　　　　：１０ＫＨｚ
データ点　　　　：６４Ｋ
ａｃｑｕｉｓｉｔｏｎ　ｔｉｍｅ　：４．９５２秒
ｐｕｌｓｅ　ｄｅｌａｙ　ｔｉｍｅ：３．０４８秒
積算回数　　　　：２５６回。
【００８０】
（３）粒子の含有量
ポリエステルとポリイミドは溶解し粒子は溶解させない溶媒を選択し、ポリエステルとポリイミドを溶解し、粒子をポリエステルから遠心分離し、粒子の基材フィルム全体重量に対する比率（重量％）をもって粒子含有量とする。場合によっては赤外分光法の併用、Ｘ線マイクロアナライザーを併用した。
【００８１】
（４）粒子の平均粒径
上記の評価方法（１）と同様にして、透過型電子顕微鏡（日立製Ｈ−６００型）を用いて、加速電圧１００ｋＶで、フィルム断面を超薄切片法（ＲｕＯ_４染色）で観察し、ＴＥＭの切片厚さは約１００ｎｍ　としＴＥＭ写真から１００視野以上測定し粒径を求めた。
【００８２】
（５）表面粗さＲａ
小坂研究所製の高精度薄膜段差測定器ＥＴ−１０を用いて中心線平均粗さＲａ（単位はｎｍ）を測定した。条件は下記のとおりである。
（測定条件）
触針先端半径：０．５μｍ
触針荷重　　：５ｍｇ
測定長　　　：１．０ｍｍ
カットオフ値：０．０８ｍｍ
フィルム幅方向に走査して２０回測定を行ない、その平均値をとった。
【００８３】
（６）熱収縮率
ＪＩＳ、Ｃ２３１８に従って測定し、熱収縮率を次式より求めた。
【００８４】
熱収縮率（％）＝［（Ｌ_０−Ｌ）／Ｌ_０］×１００
Ｌ_０：加熱処理前の標線間隔
Ｌ：加熱処理後の標線間隔
試料サイズは、幅１０ｍｍ、標線間隔２００ｍｍであり、測定は、温度１６０℃、処理時間３０分、無荷重状態で実施した。
【００８５】
（７）ガラス転移温度（Ｔｇ）
パーキンエルマー社のＤＳＣ（示差走査熱量計）ＩＩ型を用いて測定した。ＤＳＣの測定条件は次のとおりである。すなわち、試料１０ｍｇをＤＳＣ装置にセットし、３００℃の温度で５分間溶融した後、液体窒素中に急冷する。この急冷試料を１０℃／分で昇温し、ガラス転移点Ｔｇを検知する。
【００８６】
（８）固有粘度
オルトクロロフェノール中、２５℃で測定した溶液粘度から下式から計算される値を用いる。
【００８７】
ηｓｐ／Ｃ＝［η］＋Ｋ［η］２・Ｃ
ここで、ηｓｐ＝（溶液粘度／溶媒粘度）−１、Ｃは溶媒１００ｍｌあたりの溶解ポリマ重量（ｇ／１００ｍｌ、通常１．２）、Ｋはハギンス定数（０．３４３とする）である。また、溶液粘度、溶媒粘度はオストワルド粘度計を用いて測定した。
【００８８】
（９）オリゴマ抑止性
フィルムを型枠に張り付け、熱風乾燥機中で１６０℃１時間加熱し、低分子量体を強制的にフィルム表面に析出させる。この表面にアルミ蒸着を施して微分干渉顕微鏡の総合倍率４００倍の写真で観察する。写真上での析出低分子量体の総面積ｓと写真観察面積Ｓを測定し、フィルム表面積に対するオリゴマー析出面積の割合を求める。これを５０視野観察し、その平均値をオリゴマー析出指数とした。
オリゴマー指数＝（ｓ／Ｓ）×１００
評価判定は次の通りとした。
【００８９】
オリゴマー指数　０　　〜０．５未満　　：○
〃　　　　　０．５〜１．０未満　　：△
〃　　　　　１．０以上　　　　　　：×
○が好ましいが、△でも実用上問題ない。
【００９０】
（１０）耐熱性
Ａ４サイズにカットした離型フィルムを１３０℃に加熱された平滑なホットプレート上に３分間のせ、その後、室温程度の平滑な金属板上に３分間放置した。そのときの積層フィルムの表面の凹凸、界面への空気の噛み込みなどを目視で観察した。評価判定は次の通りとした。
【００９１】
◎：平面性が全く変化しなかった
○：端部が若干カールするが平面性が変化しなかった
△：平面性が悪化し表面に凹凸が生じた
×：カールがひどく多数の皺が発生した。
【００９２】
（１１）加工適性
スリット、裁断、コーティング、ラミネート、剥離時等の取り扱いにおけるフィルム破れ・裂けを観察して破れ・裂ける頻度から加工適性を評価した。
【００９３】
○：フィルム破れ・裂けが皆無である場合
△：フィルム破れが極まれに生じるが生産性が低下することなく特に問題とならない場合
×：フィルム破れが頻発する場合。
【００９４】
（１２）離型性
離型フィルムの離型層面に、幅１９ｍｍのアクリル型粘着テープ（日東電工（株）製ニットーポリエステルテープ３１Ｂ）を長さ２００ｍｍとなるように貼り付けゴムローラー（線圧２ｋｇ／ｃｍ）で圧着した。この粘着テープを２５℃５５％ＲＨ雰囲気下で引張速度３００ｍｍ／分、剥離角度１８０度で剥離した時の応力を求めた。測定は１０個の測定の平均値とした。
【００９５】
剥離力が２５ｇ／１９ｍｍ以下である場合、離型性は○、剥離力が２５ｇ／１９ｍｍを超えた場合は離型性は×、とした。
【００９６】
【実施例】
次に実施例に基づいて本発明を説明するが、必ずしもこれに限定されるものではない。
【００９７】
合成例
まず、通常の方法で、テレフタル酸ジメチル１９４重量部とエチレングリコール１２４重量部に、酢酸マグネシウム４水塩０．１重量部を加え、１４０〜２３０℃でメタノールを留出しつつエステル交換反応を行った。次いで、リン酸トリメチル０．０５重量部のエチレングリコール溶液、および三酸化アンチモン０．０５重量部を加えて５分間撹拌した後、低重合体を３０ｒｐｍで攪拌しながら、反応系を２３０℃から２９０℃まで徐々に昇温するとともに圧力を０．１ｋＰａまで下げた。最終温度、最終圧力到達までの時間はともに６０分とした。３時間重合反応させ所定の攪拌トルクとなった時点で反応系を窒素パージし常圧に戻して重縮合反応を停止し、冷水にストランド状に吐出、直ちにカッティングして、ポリエチレンテレフタレートのペレット１（固有粘度０．６５）を得た。このペレットの５０重量％とポリエーテルイミドのペレット“ウルテム１０１０”（ジーイープラスチックス社製、登録商標）の５０重量％を、２９０℃に加熱されたベント式の２軸混練押出機に供給して、剪断速度１００ｓｅｃ−１、滞留時間１分にて溶融押出し、ポリエーテルイミドを５０重量％含有したポリエステルペレット２を得た。得られたチップは透明であり、単一のガラス転移温度しか観測されなかった。
【００９８】
また、ポリエチレンテレフタレートの重合時に粒子（平均粒径１．５μｍの湿式シリカ）を４重量％添加して重合し、ペレット３（固有粘度０．６５）を得た。
【００９９】
実施例１
合成例で得られた粒子を含有しないポリエチレンテレフタレートのペレット１と、ポリエーテルイミドを５０重量％含有したペレット２と、粒子を含有したペレット３を、６．８：３：０．２の割合で混合し、１８０℃で４時間真空乾燥した後、通常の溶融押出機に供給し２９５℃で溶融押出した。これを静電印加キャスト法を用いて、表面温度２５℃のキャスティングドラム上に巻き付けて冷却固化し、未延伸フィルムを作った。
【０１００】
この未延伸フィルムを１０５℃で長手方向に３．４倍延伸した。この延伸は２組ずつのロールの周速差を利用して行った。得られた一軸延伸フィルムの両端をクリップで把持しつつ９５℃の予熱ゾーンに導き、引き続き１１５℃の加熱ゾーンで幅方向に３．６倍延伸した。更に連続的に２３０℃の熱処理ゾーンで幅方向に１０％の弛緩処理を行いながら５秒間の熱処理を施し、フィルム両端部のエッジ部分をトリミングして、フィルム厚みが３８μｍ二軸配向フィルムを得た。
【０１０１】
こうして得たフィルム表面上に空気中でコロナ放電処理を施した後、コロナ放電処理面に、離型剤としてＫＳ８５４（信越化学工業（株）製）を用い、乾燥・硬化後の厚さが０．２μｍになるようにオフセットグラビアコーターにて塗布乾燥し、本発明の離型フィルムを得た。
【０１０２】
かくして得られた離型フィルムは、剥離力１６ｇ／１９ｍｍであり、離型性が良好であった。また、スリット、裁断、コーティング、ラミネート、剥離時等のフィルム取り扱い性に優れ、フィルム破れ・裂けも全く生じることなく、加工適性も良好であった。この離型フィルムは、表１に示したとおり優れた特性を有していた。
【０１０３】
実施例２
合成例で得られたペレット１、ペレット２及びペレット３を、７．８：２：０．２の割合で混合し、実施例１と同様にして未延伸フィルムを作った。この未延伸フィルムを１００℃で長手方向に３．６倍延伸した後、１００℃で幅方向に３．７倍延伸した。更に連続的２３０℃で８秒間熱処理後、幅方向に４％の弛緩処理を行い、フィルム両端部のエッジ部分をトリミングして、二軸配向フィルムを巻き取った。
【０１０４】
次に巻き取った二軸配向フィルムを、赤外線ヒーターによる予熱温度１２０℃、本加熱処理温度が１７５℃、冷却温度１４０℃の加熱ゾーンで、フィルム張力１．０ＭＰａで２５秒間加熱処理し、フィルム厚み３８μｍの本発明の基材フィルムを得た。こうして得たフィルム表面上に空気中でコロナ放電処理を施した後、コロナ放電処理面に、離型塗剤のフッ素含有樹脂として、含フッ素アクリル樹脂“フリリース”ＲＢＸ−７２５ＮＦ（ネオス（株）製）と、フッ素系オイルとして“クライトックス”１５７−ＦＳＭ（デュポン社製）を、“フロリナ−ト”ＦＣ−７７（３Ｍ社製）を希釈溶剤として、重量固形分比２０：８０の組成で均一分散させた濃度３重量％の塗剤をバーコート方式で塗布し、１２０℃１分間乾燥させ、離型層厚み０．３５μｍ形成した離型フィルムを得た。
【０１０５】
得られた離型フィルムは、剥離力７ｇ／１９ｍｍであり、離型性が良好であった。また、スリット、裁断、コーティング、ラミネート、剥離時等のフィルム取り扱い性に優れ、フィルム破れ・裂けも全く生じることなく加工適性も良好であった。この離型フィルムは、表１に示したとおり優れた特性を有していた。
【０１０６】
実施例３
塗料組成が、植物系ワックス（１００重量部）｛水添ロジン・α、β置換エチレン（α置換基：カルボキシル、β置換基：メチル）付加物］・アルキル（炭素数６）ポリ（繰り返し単位：５）アルコールのエステル化合物を水分散塗料とするために、非イオン性界面活性剤、リン酸エステル（ブトキシエチル化合物）、オレイン酸アンモニウム、２−アミノ−２−メチルプロパノールを各１重量部添加し、水中で強攪拌し、さらに超音波分散機で全固形分比率が１重量％の水分散液を作成した。実施例１と同様にして、長手方向に３．４倍延伸した一軸延伸フィルムの片面にコロナ放電処理を施し、その表面上にバーコート方式で上記組成の水分散塗料をインラインコートした。このコートした一軸延伸フィルムをテンターに導き、１１０℃の予熱工程で水分を乾燥させた後、１２５℃に加熱しつつ、幅方向に４倍延伸し、続いて２２５℃で熱固定を行ない、離型層厚さが０．０５μｍのフィルムを得た。その後、実施例２と同様に赤外線ヒーターによる予熱温度１００℃、本加熱処理温度が１３０℃、冷却温度１２０℃の加熱ゾーンで、加熱処理し、フィルム厚みが３８μｍの離型フィルムを得た。
【０１０７】
得られた離型フィルムは、剥離力２０ｇ／１９ｍｍであり、離型性が良好であった。また、スリット、裁断、コーティング、ラミネート、剥離時等のフィルム取り扱い性に優れ、フィルム破れ・裂けも全く生じることなく加工適性も良好であった。この離型フィルムは、表１に示したとおり優れた特性を有していた。
【０１０８】
実施例４
合成例で得られたポリエチレンテレフタレートのペレット１と、ポリエーテルイミドを５０重量％含有したペレット２を、２：８の割合で混合し（ポリマーＡ）、１８０℃で４時間真空乾燥した後、通常の溶融押出機Ａに供給し２９５℃で溶融した。また、前記ペレット１、ペレット２及びペレット３を９：０．５：０．５の割合で混合し（ポリマーＢ）、それぞれ１８０℃で４時間真空乾燥した後、通常の溶融押出機Ｂに供給し２８５℃で溶融した。これらのポリマーを通常の方法で濾過し、２層用の矩形の合流ブロック（フィードブロック）にて、ポリマーＡ層／ポリマーＢ層の２層積層の未延伸フィルムを得た。各層の厚みはそれぞれのラインに設置されたギヤポンプの回転数を調節して押出量を制御することによって調節した。この未延伸フィルムを実施例１と同様にして、フィルム厚みが３８μｍ（Ａ層／Ｂ層＝２／３６μｍ）である二軸配向フィルムを得た。次にこの二軸配向フィルムを、赤外線ヒーターによる予熱温度１２０℃、本加熱処理温度が１８０℃、冷却温度１３０℃の加熱ゾーンで、フィルム張力１．０ＭＰａで１５秒間加熱処理し、フィルム厚み３８μｍの本発明の基材フィルムを得た。この基材フィルムのＡ層側に実施例１と同様にして離型層を設けて離型フィルムを得た。
【０１０９】
得られた離型フィルムは、剥離力１８ｇ／１９ｍｍであり、離型性が良好であった。また、スリット、裁断、コーティング、ラミネート、剥離時等のフィルム取り扱い性に優れ、フィルム破れ・裂けも全く生じることなく、加工適性も良好であった。この離型フィルムは、表１に示したとおり優れた特性を有していた。
【０１１０】
実施例５
基材フィルムの構成を、Ａ／Ｂ／Ａの３層の積層構成とした。Ｂ層には、通常の方法により得られたポリエチレン−２，６−ナフタレート（ＰＥＮ）のペレットの９０重量％とポリエーテルイミド（ＰＥＩ）のペレットの１０重量％を混合し、３００℃に加熱されたベント式の２軸混練押出機に供給して、溶融押出し、ポリエーテルイミドを１０重量％含有したＰＥＮ／ＰＥＩのペレットを用いた。これを１８０℃で４時間真空乾燥した後、通常の溶融押出機Ｂに供給し３０５℃で溶融した。Ａ層には、実施例２のポリマーと同様のものを用い、乾燥し、これを溶融押出機Ａに供給し２９０℃で溶融した。これらの溶融ポリマーを通常の方法で濾過し、３層用の矩形の合流ブロック（フィードブロック）にて、Ａ／Ｂ／Ａを積層した。これを静電印加キャスト法を用いて、表面温度２５℃のキャスティングドラム上に巻き付けて冷却固化し、未延伸フィルムを作った。
【０１１１】
この未延伸フィルムを１３０℃で長手方向に３．８倍延伸し、幅方向に１３０℃の加熱ゾーンで幅方向に４．５倍延伸した。更に連続的に２３０℃の熱処理ゾーンで１０％の弛緩処理を行いながら５秒間の熱処理を施し、フィルム両端部のエッジ部分をトリミングして、フィルム厚みが３８μｍ、（Ａ／Ｂ／Ａ＝２／３４／２μｍ）の二軸配向積層フィルムを得た。この二軸配向積層フィルムを実施例４と同様にして、１８０℃でアニール処理し離型層を設けて離型フィルムを得た。
【０１１２】
得られた離型フィルムは、剥離力１７ｇ／１９ｍｍであり、離型性が良好であった。前記、フィルム両端部のエッジトリミング開始時と、剥離テスト用のサンプリング中にそれぞれ１回ずつフィルム破れが生じたが、特に問題もなく、フィルム取り扱い性が良好であった。この離型フィルムは、表１に示したとおり優れた特性を有していた。
【０１１３】
比較例１
ポリエーテルイミド含有ペレット２を混合しないことと、長手方向の延伸温度を９３℃、延伸倍率３．６倍、そして幅方向の延伸温度を９５℃、延伸倍率３．７倍にすること以外は、実施例１と同様にして離型フィルムを得た。
【０１１４】
得られた離型フィルムは、剥離力２４ｇ／１９ｍｍであり、離型性は良好であったが、熱収縮率が大きくなり、また、耐熱性、オリゴマー抑止性が不良であった。
【０１１５】
比較例２
ＰＥＮ重合時に粒子（平均粒径１．０μｍの湿式シリカ）を０．０８重量添加したものを用い、ポリイミドを含有しないポリマーを用いて、押出温度３００℃で溶融押出した。これを実施例１と同様にして、１２８℃で長手方向に３．４倍１２５℃の加熱ゾーンで幅方向に３．６倍延伸した。更に連続的に２３０℃の熱処理ゾーンで１０％の弛緩処理を行いながら５秒間の熱処理を施し、さらに離型層を設けて、フィルム厚みが３８μｍ離型フィルムを得た。
【０１１６】
得られた離型フィルムは、剥離力１９ｇ／１９ｍｍであり、離型性が良好であったが、この離型フィルムは、スリットや、コーティング時のワインダー巻き取り時に破れ生産性が低下するものであった。また、サンプリングの裁断時に破れ・裂けが頻繁に発生し、取り扱い性が不良であった。また、オリゴマー抑止性も不良であった。
【０１１７】
【表１】

【０１１８】
【発明の効果】
本発明によって得られる離型フィルムは、耐熱性、オリゴマー抑止性に優れているので、種々の用途で使用するための加工工程において高温熱処理された場合でも平面性が悪化せず、オリゴマー析出が大幅に抑制できる。従って、これらの特性を生かして、粘着ラベルシールや粘着テープ等の台紙や、貼付薬保護シート、成形樹脂表面保護シート、あるいは液晶ディスプレイに用いられる偏光板や位相差板等の液晶表示板保護シート、建築資材用の保護シート等の保護用に好適に使用することができ、さらに、塩ビ、ウレタン等合成皮革製造用、感圧接着フィルム製造用、炭素繊維プリプレグ用、セラミックシート、積層セラミックコンデンサー製造用あるいは高密度実装の回路基板等の各種成型品の製造用などの各種工業材料などとして好適に使用することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a release film. In particular, the present invention relates to a release film which is excellent in heat resistance, dimensional stability and oligomer deterrence, and is also excellent in workability at the time of lamination, slitting and cutting.
[0002]
[Prior art]
Conventionally, various base films have been used as release films. Release films are used for backing paper such as adhesive label seals and adhesive tapes, adhesive protection sheets, molded resin surface protection sheets, or liquid crystal display panel protection sheets such as polarizing plates and retardation plates used for liquid crystal displays, and building materials. For the protection of protective sheets, etc., for the production of synthetic leather such as PVC and urethane, for the production of pressure-sensitive adhesive films, for the preparation of carbon fiber prepregs, for the production of ceramic sheets, multilayer ceramic capacitors, and for high-density circuit boards. It is used for manufacturing molded products.
[0003]
In order to sufficiently cure a release layer generally used for a release film, for example, a release layer composed of a thermosetting silicone-based release agent, it is necessary to cure at a high temperature for a long time. In addition, due to the heat treatment in the processing step of the release film and the increase in temperature for increasing the processing speed, the release film is required to have improved heat resistance and dimensional stability that affect the flatness of the film.
[0004]
Further, when the release film is heated in the processing step of the release film, oligomers are precipitated on the film surface, resulting in process dirt and deterioration of product quality. Therefore, it is necessary to suppress the precipitation of oligomers. For this reason, as a conventional method for reducing the amount of oligomers, for example, a method in which polyester is heat-treated in an inert atmosphere having a melting point or lower has been proposed in Patent Document 1 (see Patent Document 1).
[0005]
However, although this method has the effect of reducing oligomers, it requires a heat treatment apparatus, which is not economically preferable.
[0006]
Further, a method has been proposed in which a higher fatty acid ester or a metal salt of dodecylbenzene sulfonic acid is contained in polyester to suppress oligomer precipitation (see Patent Document 2).
[0007]
However, this method has a problem that the effect of suppressing the precipitation of oligomers is not sufficient or these components contained in the polyester form coarse crater-like defects on the film surface due to bleed-out and the like. I was
[0008]
In addition, a release film has been proposed in which a coating layer containing polyvinyl alcohol and a release layer are sequentially provided to reduce the precipitation of oligomers (see Patent Document 3).
[0009]
Regarding heat resistance, a polyethylene 2,6 naphthalate film (hereinafter, sometimes referred to as a PEN film) having a higher heat resistance than a polyethylene terephthalate film (hereinafter, sometimes referred to as a PET film) has been proposed as a base film. (See Patent Documents 4 and 5).
[0010]
Japanese Patent Application Laid-Open No. 62-198445 discloses that a biaxially stretched PEN film obtained from a PEN having a specific resistance upon melting, particularly a smooth surface is used as a base film, on which a thermosetting silicone resin is laminated. Have been. In order to obtain such a specific PEN, it must be produced by a special polymerization method. In addition, PEN is generally easy to tear and easy to break, so that it may be broken, for example, in a high-speed processing process, or in laminating, slitting, cutting, etc., and is not necessarily satisfactory in terms of workability, yield, and cost. Was not.
[0011]
[Patent Document 1]
JP-A-2-298521
[0012]
[Patent Document 2]
JP-A-3-227328
[0013]
[Patent Document 3]
JP 2001-71420 A
[0014]
[Patent Document 4]
JP-A-62-198445
[0015]
[Patent Document 5]
JP-A-3-177474
[0016]
[Problems to be solved by the invention]
The release film of the present invention improves the drawbacks of a conventional release film using PET or PEN as a base film. In other words, without using a heat treatment device or oligomer inhibitor for oligomer reduction, and without using a special PEN having a specific resistance at the time of melting, it is excellent in oligomer precipitation inhibition and heat resistance, and can be used for laminating, slitting and cutting. An object of the present invention is to provide a release film which is excellent in processability and the like and can be developed for various uses.
[0017]
[Means for Solving the Problems]
In order to achieve this object, the release film of the present invention is characterized in that a release layer is provided on at least one surface of a base film made of a resin composition containing polyester and polyimide.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
The release film of the present invention is a film in which a release layer is provided on at least one surface of a base film made of a resin composition containing polyester and polyimide.
[0019]
The polyester in the present invention is not particularly limited, but is selected from ethylene terephthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate and ethylene-2,6-naphthalate units. It is preferable that at least one type of structural unit is the main component, and particularly preferable is polyethylene terephthalate, polyethylene-2,6-naphthalate, or a copolymer or modified product thereof. Two or more polyesters may be mixed or a copolymerized polymer may be used as long as the effects of the present invention are not impaired.
[0020]
The polyimide in the substrate film of the present invention is not particularly limited as long as it has melt moldability and is a polyimide compatible with polyester. For example, tetracarboxylic acid and / or an acid anhydride thereof and an aliphatic primary Examples include polymers obtained by dehydration polycondensation of one or more compounds selected from the group consisting of monoamines, aromatic primary monoamines, aliphatic primary diamines, and aromatic primary diamines. Among them, as the polyimide, polyetherimide containing an ether bond in the polyimide component is preferable from the viewpoints of melt moldability with polyester and handleability.
[0021]
The term “compatible” as used in the present invention means that a chip obtained by blending has a single glass transition temperature (Tg). The single glass transition temperature means that there is only one glass transition temperature between the glass transition temperature of the polyester and the glass transition temperature of the polyimide in a differential scanning calorimeter (DSC) measurement. If two or more glass transition temperatures are observed between the glass transition temperature of the polyester and the glass transition temperature of the polyimide, the compatibility between the polyester and the polyimide is insufficient, and the film is easily broken at the time of film formation, resulting in production. May be reduced.
[0022]
In the present invention, the time at which the polyimide is added to the polyester is not particularly limited, but may be added before the polymerization of the polyester, for example, before the esterification reaction, or after the polymerization and before the melt extrusion. Before melt extrusion, polyester and polyimide may be pelletized and used.
[0023]
The base film of the present invention is preferably a laminated film having at least two layers. When the substrate film of the present invention is a laminated film, at least one of the layers is a layer made of a resin composition containing polyester and polyimide. It is preferable that the base film of the present invention is a laminated film, because the processability and handleability are further improved, and the characteristics of the release film of the present invention are easily obtained. The number of layers in this case is not particularly limited, but 2 to 5 layers are preferable in terms of productivity.
[0024]
In the present invention, the content of the polyester and the polyimide in the resin composition is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more, in total.
[0025]
In the present invention, the polyimide in the base film is preferably a polyetherimide. The content of the polyetherimide in the film layer is preferably 5 to 50% by weight, more preferably 7 to 45% by weight, and further preferably 10 to 40% by weight. When the content of the polyetherimide in the film layer is 5 to 50% by weight, it is preferable from the viewpoints of heat resistance, oligomer inhibition, and the like.
[0026]
The content in the film layer referred to in the present invention is the entire film when the base film is a single layer, and when the base film is a laminated film of two or more layers, each layer is formed. Means the content of each layer with respect to the composition (including particles when the polymer contains particles). For example, when the base film is a two-layer laminated film of the A / B layer, the content of the A layer is defined as the composition forming the A layer (when the polymer A contains particles, The content of the B layer is the content of the polyimide in the composition forming the B layer (including the particles when the polymer B contains the particles). Rate.
[0027]
Since the melt viscosities of polyester and polyimide are greatly different, if the content of polyimide is low, it may be difficult to make them compatible with each other even if they are sufficiently kneaded in an extruder. When the content exceeds 50% by weight, extrusion and stretching become difficult and productivity may be deteriorated.
[0028]
The base film composed of the resin composition containing the polyester and the polyimide of the present invention as main components may contain various additives and crosslinking agents within a range not to impair the effects of the present invention. Examples thereof include antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic and inorganic particles, pigments, dyes, antistatic agents, organic lubricants such as fatty acid esters and waxes.
[0029]
Among them, it is preferable that particles are contained in the film, which gives the film an appropriate lubricity and is suitable for processing at the time of laminating or slit cutting. The particles to be added are not particularly limited, but inorganic particles such as carbon black, zeolite, mica, titanium oxide, calcium carbonate, kaolin, talc, wet or dry silica, colloidal silica, aluminum silicate, calcium phosphate, barium sulfate, alumina and zirconia Particles, organic particles containing acrylic acid, styrene, or the like as constituents, so-called internal particles that are precipitated by a catalyst or the like added during the polyester polymerization reaction, and the like are included.
[0030]
The average particle diameter of the added particles is preferably 0.01 to 5 μm, more preferably about 0.1 to 4 μm, and further preferably about 0.20 to 3 μm. Further, the content of the added particles in the base film is preferably 0.005 to 30% by weight, more preferably 0.01 to 25% by weight, and further preferably 0.1 to 20% by weight. If the particle content is less than 0.005% by weight, it is difficult to obtain slipperiness, while if it exceeds 30% by weight, the film strength tends to decrease, and the film tends to be broken during the film production process and the processing step, resulting in a decrease in productivity. There are cases.
[0031]
It is preferable that the base film of the present invention is biaxially stretched in the longitudinal direction and the width direction to give orientation. As a stretching method, a sequential biaxial stretching method such as stretching in the width direction after stretching in the longitudinal direction, a simultaneous biaxial stretching method in which the longitudinal direction and the width direction are simultaneously stretched using a simultaneous biaxial tenter, and the like, And a method in which a sequential biaxial stretching method and a simultaneous biaxial stretching method are combined.
[0032]
The center line average roughness (Ra) of at least one surface of the substrate film of the present invention is preferably 1 to 100 nm, more preferably 2 to 80 nm, and further preferably 5 to 50 nm. If the center line average roughness is less than 1 nm, the film surface is too smooth, and the slipperiness becomes insufficient, and workability and handleability may become difficult.
[0033]
When the difference between the center line average roughnesses (Ra) of the front and back surfaces of the base film is 0 to 100 nm, processability and handleability are further improved, and the characteristics of the release film of the present invention can be easily obtained. When making a difference in the surface roughness of the front and back of the base film, if a release layer is provided on the smaller surface roughness, for example, the surface to be peeled off after peeling when used as a release film for a ceramic sheet It is preferable because a material excellent in surface flatness and the like can be easily obtained and also has a slipperiness on the opposite side of the release film, so that workability and handleability are further improved.
[0034]
The heat shrinkage of the substrate film of the present invention is preferably 0.7% or less, more preferably 0.6% or less, and still more preferably 0.5% or less when heated at 150 ° C. for 30 minutes. By keeping the heat shrinkage of the base film low in this way, it is possible to dry or heat (or radiation) cure over time at a higher temperature when coating the release layer, and for a longer time at a higher temperature. Even after drying or heat (or radiation) curing, wrinkles and curls can be suppressed as a release film. When the heat shrinkage is larger than 0.7%, the film tends to expand and contract or deform due to long-term storage under high temperature and high humidity, and the film tends to meander at the time of processing. In some cases, curl, wrinkles, or looseness may easily cause deterioration in flatness.
[0035]
The coefficient of thermal expansion of the base film of the present invention at 160 to 60 ° C. is not particularly limited, but the characteristics of the present invention can be obtained by setting preferably 50 ppm or less, more preferably 45 ppm or less, and still more preferably 40 ppm. It becomes easy to be.
[0036]
The substrate film of the present invention can be used in any of unoriented, uniaxial and biaxial orientations, but is preferably a biaxially oriented film because of its excellent mechanical strength. The biaxially oriented film refers to a film in which molecules are oriented in the longitudinal direction of the film and in a direction (width direction) perpendicular to the longitudinal direction. Specifically, a method in which a substantially non-oriented film obtained by melt-extruding a polymer is stretched in the longitudinal direction and then stretched in the width direction, after stretching in the width direction, and stretched in the longitudinal direction, or in the longitudinal direction and width. The stretching may be performed simultaneously in the directions, or the stretching in the longitudinal direction and the stretching in the width direction may be performed plural times in combination. When the base film is a laminated film having at least two layers, it is preferable that at least one layer is a biaxially oriented film.
[0037]
The release film of the present invention is preferably a biaxially oriented film. Furthermore, the heat shrinkage, which is the fate of the biaxially oriented film, is sufficiently reduced in both the longitudinal and width directions, and as a method for obtaining a film having good flatness, the film is biaxially stretched by the known method. It is effective to perform a relaxation treatment while performing heat setting or cooling the film to reduce the heat shrinkage. This relaxation may be carried out continuously in the film forming process, or, after the formed film is wound once, the film roll is subjected to an aging or annealing method, or a combination of both. Alternatively, the aging or annealing treatment may be performed on the material subjected to the relaxation treatment in the film forming step. It is more preferable to perform the relaxation treatment in combination of both, because the heat shrinkage can be further reduced and the heat resistance and the dimensional stability are improved.
[0038]
In the annealing treatment, the roll film wound after film formation is caused to travel through the heating zone at a transport tension of 0.2 to 1.2 MPa. If the transport tension is less than 0.2 MPa, the film may meander or the end of the film may have a petal shape, resulting in poor flatness. If this tension exceeds 1.2 MPa, the residual stress of the film may not be sufficiently relaxed, and it may be difficult to obtain a sufficiently low heat-collecting film. In this case, the heating time in the heating zone is preferably 1 to 35 seconds, more preferably 5 to 30 seconds, and still more preferably 10 to 20 seconds. If the heating time is less than 1 second, it may be difficult to obtain a sufficiently low heat-collecting film. On the other hand, when the time exceeds 35 seconds, the flatness of the film may be deteriorated, and the size of the apparatus may be increased and productivity may be reduced.
[0039]
Furthermore, in the present invention, in order to obtain a film having good flatness and excellent thermal dimensional stability, the temperature distribution of the heat treatment zone is preheated, heating at the relaxation treatment temperature, cooling and heating of the transport film are gradually performed. It is preferable that the film temperature is gradually raised to room temperature rather than rapidly cooled even when cooling, because a film having more excellent flatness can be obtained. The preheating for raising the film temperature in this case is preferably performed at a glass transition temperature Tg of at least 30 ° C., more preferably at Tg of 20 ° C., and still more preferably at least Tg. To 200 ° C., more preferably 110 ° C. to 195 ° C., even more preferably 120 ° C. to 190 ° C., and when the film cooling temperature is Tg-50 ° C. or higher, a film with low heat yield and excellent flatness Is preferred because The method of heat treatment of the film in the case of annealing may be any known method, such as a method using a heating roll, a method in which the film is conveyed in the air of a heating oven or on a guide roll and hot air is blown, or a method of heating with an infrared heater or the like. And heating with an infrared heater is particularly preferred.
[0040]
By subjecting the biaxially oriented film to heat treatment under the above conditions, not only the effect of maintaining the flatness as described above can be obtained, but also the remaining strain is removed only by heat fixing at the time of film formation, and the heat shrinkage occurs. And a film having excellent thermal dimensional stability can be obtained.
[0041]
When the substrate film of the present invention is a film that has been subjected to a surface treatment by a known method, that is, a corona discharge treatment, a plasma treatment or an easy adhesion treatment, the adhesion to the release layer, water resistance, chemical resistance, and the like. Can be more preferably used. In addition, for the easy adhesion treatment, various known methods can be used.Acrylic, urethane, polyester-based various easy adhesives are applied in the film manufacturing process, or after uniaxial or biaxial stretching. A film obtained by applying the above-mentioned various easy-adhesives to a film or the like can be used publicly. In the case of a silicone resin-based release layer, a surface treated with a known silane coupling agent is particularly effectively used.
[0042]
The thickness of the base film of the present invention is not particularly limited, and for example, can be set to an appropriate thickness in the range of about 5 to 500 μm in consideration of the stiffness required for the release film.
[0043]
Further, in the present invention, the release layer provided on at least one side of the base film made of the resin composition containing polyester and polyimide is not particularly limited as long as it is a known one. A resin containing at least one selected from a resin, a fluorine resin, an acrylic resin, and a wax can be suitably used.
[0044]
As the silicone resin, those generally known as release agents can be used, and can be selected from known ones described in “Silicone Material Handbook” (edited by Toray Dow Corning, 1993. 8) and the like. it can.
[0045]
Heat or radiation curing type is common, as a specific curing method,
(1) Thermal condensation reaction type: a reaction in which dimethylpolysiloxane having silanol groups at both ends is reacted with methylhydrogenpolysiloxane or methylmethoxysiloxane in the presence of an organotin-based catalyst;
(2) Non-heat-reactive type: a product obtained by reacting methylvinylpolysiloxane having a vinyl group at both ends of a molecular chain and a side chain group with methylhydrogenpolysiloxane in the presence of a platinum-based catalyst,
(3) Ultraviolet curing type: (3.1) Non-radical type: A siloxane containing an alkenyl group and a mercapto group added with a photopolymerizing agent, (3.2) Hydroxyl type: The same platinum type as the heat non-reactive type Using a catalyst, (3.3) Radical polymerization type: (meth) acrylic group-containing siloxane plus a photopolymerizing agent, (3.4) Cationic polymerization type: Epoxy-containing siloxane onium salt With the addition of a photoinitiator,
(4) Electron beam-curable type: radical polymerizable group-containing siloxane (with or without a functional group, and with or without a photoinitiator).
[0046]
The form of the coating material can be appropriately selected and used from a coating type emulsion type, a solventless type, and the like.
[0047]
Known fluororesins can be used as the fluororesin, and among them, those containing a compound represented by the following general formula as the main component of the fluorine-containing resin or a fluorine-containing resin and fluorine oil Those having a main component are preferably used.
[0048]
Embedded image

[0049]
Examples of such a fluorine-containing resin include a polymer (including an oligomer) or a copolymer comprising a fluorine-containing vinyl polymerizable monomer, or a fluorine-containing vinyl polymerizable monomer and a vinyl polymer containing no fluorine atom. And a mixture thereof with at least one of the hydrophilic monomers, or a mixture thereof having 5 to 80 mol% of fluorine atoms.
[0050]
Specific examples of the polymer comprising a fluorine-containing vinyl polymerizable monomer include poly [2- (perfluorononenyloxy) ethyl methacrylate], poly [2- (perfluorononenyloxy) ethyl acrylate], and poly [2- (perfluorononenyloxy) ethyl acrylate]. [2- (perfluorononenyloxybenzoyloxy) ethyl methacrylate], poly [2- (perfluorononenyloxybenzoyloxy) ethyl acrylate], poly [2,2,2-trifluoroethyl methacrylate], poly [2 2,2,2-trifluoroethyl acrylate], poly [2,2,3,3,3-pentafluoropropyl methacrylate], poly [1-methyl-2,2,3,3,4,4-acrylic acid, Hexafluorobutyl methacrylate], poly [1-methyl-2,2 acrylic acid, 3,3,4,4, Hexafluorobutyl acrylate], poly [perfluoroheptylethyl methacrylate], poly [perfluoroheptylethyl acrylate], poly [perfluoroheptylvinyl ether], poly [α, β, β-trifluorostyrene], polyvinylidene fluoride, poly Hexafluoropropylene, polytetrafluoroethylene and the like can be mentioned. Among these, poly [perfluoromethacrylate] and poly [perfluoroacrylate] are preferable, particularly from the viewpoint of affinity for the base film.
[0051]
Examples of the vinyl polymerizable monomer containing no fluorine atom that is copolymerized with the fluorine-containing vinyl polymerizable monomer include a hydrocarbon-based vinyl polymerizable monomer, a hydrocarbon-based non-conjugated divinyl polymerizable monomer, and a functional group. Examples of the compound include a group-containing vinyl polymerizable monomer, and examples of the hydrocarbon-based vinyl polymerizable monomer include methyl acrylate, propyl acrylate, butyl acrylate, isoamyl acrylate, and acrylic acid 2- Ethylhexyl, octyl acrylate, octadecyl acrylate, lauryl acrylate, cesyl acrylate, N, N-diethylaminoethyl acrylate, methyl methacrylate, propyl methacrylate, butyl methacrylate, isoamyl methacrylate, 2-ethylhexyl methacrylate, methacryl Octyl acid, octadecyl methacrylate, methacrylic acid Lauryl acrylate, cesyl methacrylate, N, N-diethylaminoethyl methacrylate, vinyl acetate, vinyl propionate, vinyl caprate, vinyl laurate, vinyl stearate, styrene, α-methylstyrene, p-methylstyrene, vinyl fluoride , Vinyl chloride, vinyl bromide, vinylidene fluoride, vinylidene chloride, allyl heptanoate, allyl acetate, allyl caprate, allyl caproate, vinyl methyl ketone, vinyl ethyl ketone, 1,3-butadiene, 2-chloro-1, Examples of hydrocarbon-based non-conjugated divinyl copolymers such as 3-butadiene, 2,3-dichloro-1,3-butadiene and isoprene include, for example, ethylene glycol diacrylate, ethylene glycol methacrylate, propylene glycol diacrylate, diethylene glycol As a functional group-containing vinyl copolymerizable monomer such as diol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, divinylbenzene, vinyl acrylate, dibromoneopentyl glycol dimethacrylate, etc. For example, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-butoxymethylacrylamide, N-butoxymethylacrylamide, diacetone acrylamide, methylol diacetone acrylamide, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, Examples include 3-chloro-2-hydroxypropyl methacrylate and the like. , Are selected from among these is not particularly limited.
[0052]
Typical examples of the fluorine-based oil used as the fluorine-based resin and the one containing a fluorine-based oil as a main component include perfluoropolyether perfluorinated oil and the like. Specifically, for example, the following chemical formula And the like as a main component.
[0053]
Embedded image

[0054]
Embedded image

[0055]
Embedded image

[0056]
Embedded image

[0057]
Embedded image

[0058]
Among them, in the present invention, a compound represented by Chemical Formula 2 is preferable in terms of releasability.
[0059]
In addition, the copolymerization amount is such that a release layer containing the fluorine-containing resin and the fluorine-based oil as main components is applied to at least one side of the base film. As a solvent for the fluorine-containing resin and the fluorine-based oil, for example, alcohol System, carboxylic acid ester system, ketone system, aliphatic hydrocarbon alicyclic or aromatic hydrocarbon system, halogenated hydrocarbon system, fluorine system, and a mixture thereof.
[0060]
Various known waxes can be used as the wax. For example, petroleum-based wax, vegetable-based wax, mineral-based wax, animal-based wax, low-molecular-weight polyolefins and the like can be used without any particular limitation, but petroleum-based wax and vegetable-based wax are particularly preferably used. . Examples of the petroleum wax include paraffin wax, microcrystalline wax, and oxidized wax. Examples of the vegetable wax include candelilla wax, carnauba wax, wood wax, oligurie wax, sugarcane wax, and rosin-modified wax. Among them, those comprising the following composition are particularly preferred. That is, rosin or disproportionated rosin, or hydrogenated rosin, α, β-substituted ethylene (α-substituent: carboxyl, β-substituent: hydrogen or methyl or carboxyl) adduct], alkyl or alkenyl (each having 1 to 8 carbon atoms) ) It is preferable to use an ester adduct of poly (repeating unit: 1 to 6) alcohol from the viewpoint of releasability and slipperiness, and it is more preferable to use a mixture with the above-mentioned oxidized wax.
[0061]
When a release layer containing the wax of the present invention as a main component is further added with an oily substance, the release property at high temperatures can be improved. Here, the oily substance is a liquid or paste-like oil at normal temperature, and examples thereof include vegetable oils, fats and oils, mineral oils, synthetic lubricating oils, and mixtures thereof. Among these, mineral oils and synthetic lubricating oils having good releasability at high temperatures are preferred. The oily substance is preferably added in an amount of 100 parts by weight of the wax composition, more preferably 3 to 50 parts by weight.
[0062]
Further, the release layer of the present invention may contain known additives in a range that does not impair the purpose of the present invention, such as an antifoaming agent, a coating improver, a thickener, an antistatic agent, an antioxidant, and an ultraviolet absorber. Agents, hardeners, dyes, etc., or fine particles of inorganic or organic compounds may be contained as lubricants.
[0063]
The thickness of the release layer formed in the present invention is preferably 0.01 to 20 μm, more preferably 0.02 to 15 μm, and even more preferably 0.05 to 13 μm. If the thickness of the release layer is less than 0.01 μm, unevenness in the thickness of the coating layer is generated, which greatly affects the release performance, and there is a possibility that a portion where desired release performance cannot be obtained may occur. Conversely, if it exceeds 20 μm, it takes a long time to dry and harden the coating film, which is inconvenient in production. In addition, a large amount of release agent material is required, and the release layer itself may become brittle.
[0064]
Next, specific examples of the method for producing a release film of the present invention will be described, but the present invention is not limited to the following description.
[0065]
First, an example in which polyethylene terephthalate is used as the base film and polyetherimide is used as the polyimide will be described. The polyetherimide is not particularly limited, and for example, "Ultem" (manufactured by General Electric) can be used.
[0066]
First, according to a conventional method, bis-β-hydroxyethyl terephthalate (BHT) is obtained by esterifying terephthalic acid and ethylene glycol or by transesterifying dimethyl terephthalate and ethylene glycol. Next, while transferring the BHT to the polymerization tank, the BHT is heated to 280 ° C. under vacuum to perform polymerization. At this time, a predetermined amount of polyetherimide may be added. If necessary, the obtained polyester pellets are subjected to solid-state polymerization under reduced pressure. In the case of solid phase polymerization, after preliminarily precrystallizing at a temperature of 180 ° C. or lower, solid phase polymerization is performed at 190 to 250 ° C. under a reduced pressure of about 1 mmHg for 3 to 50 hours, and the intrinsic viscosity is 0.5 to 1.5. Make (dl / g) pellets.
[0067]
Further, polyethylene terephthalate pellets and polyetherimide pellets polymerized by a known method are mixed at an arbitrary ratio, and the mixture is supplied to a vented twin-screw extruder heated to 270 to 300 ° C. and melt-extruded. Knead both. The residence time is preferably 0.5 to 20 minutes, more preferably 1 to 15 minutes. If necessary, the obtained chips may be again introduced into the twin-screw extruder and extrusion may be repeated until the chips are compatible. By the above kneading, polyethylene terephthalate and polyetherimide are compatible with each other, and pellets of the mixed polyester having a single glass transition point can be obtained.
[0068]
When particles are contained in the base film, it is preferable that the particles be contained in the polyester from the viewpoint of uniform compatibility between the polyester and the polyimide. A method is preferred in which a predetermined ratio of particles is added to and dispersed in ethylene glycol in the form of a slurry, and then the ethylene glycol is polymerized with terephthalic acid. When adding the particles, for example, if the water sol or alcohol sol obtained during the synthesis of the particles is added without drying once, the dispersibility of the particles is good. It is also effective to directly mix the water slurry of the particles with predetermined polyester pellets and knead the polyester with a vented twin-screw extruder.
[0069]
As a method for adjusting the content of polyetherimide or particles, a pellet containing a high concentration of the polyetherimide prepared by the above method, or a PET master pellet containing a high concentration of the particles is prepared and then prepared. When forming a film, a method of diluting with a polyester pellet substantially containing no particles and adjusting the respective contents is effective.
[0070]
Next, these polyesters, polyetherimides, and pellets containing particles or blended pellets are vacuum-dried at 110 to 190 ° C. for 3 hours or more, and then melt-extruded from a slit die with an extruder, It is cooled and solidified on a casting drum at 20 to 60 ° C. to form an unstretched film. In this case, it is preferable to use various filters, for example, a filter made of a material such as a sintered metal, a porous ceramic, a sand, or a wire mesh in order to remove foreign substances and a deteriorated polymer in the molten polymer. In addition, a method of installing a static mixer and a gear pump in each polymer flow channel as needed to control the amount of polymer extruded is effective for obtaining the effects of the present invention.
[0071]
When the configuration of the base film is, for example, a two-layer laminated configuration (layer A / layer B), melt extrusion is performed by using two extruders using a laminating manifold or a rectangular merging block in the same manner as described above, and laminating unstretched. Get the film. In this case, the difference (absolute value) between the intrinsic viscosities of the polymers constituting the polyester A layer and the B layer should be in the range of 0 to 1.2 (dl / g), preferably 0 to 1 (dl / g). However, it is effective for stably and industrially producing the base film of the present invention. In the unstretched film, the draft ratio (= flow rate of the lip polymer of the die / flow rate of the film (polymer) on the casting drum) when the polymer in the molten state is extruded from the die is 5 to 30 to obtain the film of the present invention. Preferred above.
[0072]
Next, the unstretched film is first stretched in the longitudinal direction. The stretching in the longitudinal direction is usually performed using a roll, and the stretching temperature is 80 to 180 ° C, preferably 90 to 160 ° C. Stretching in the longitudinal direction is performed in one or two or more stages, and is preferably performed in a range of 2 to 8 times, preferably 2.5 to 6 times.
[0073]
Thereafter, the film is guided to a tenter while holding both ends of the film with clips. After preheating in a tenter, stretching is performed 2.5 to 8 times, preferably 3 to 6 times in the width direction, at a stretching speed of 3000 to 30000% / min. The base film stretched in the width direction is further subjected to a heat treatment. The stretching temperature is preferably from 80 to 160 ° C, preferably from 90 to 150 ° C, and the heat treatment temperature is preferably from 185 to 245 ° C. If the heat treatment temperature is increased more than necessary, the crystal orientation is likely to be lost and the flatness is deteriorated and the rigidity is liable to be lowered. Good. In addition, since the heat shrinkage remains by the above heat treatment alone, if the distortion of the film cannot be completely removed, if necessary, the film is relaxed in the longitudinal direction and the width direction while being thermally fixed or wound up while cooling the film. . When the relaxation rate is 0.5 to 10% or less, it is effective to maintain flatness and obtain a film having excellent thermal dimensional stability.
[0074]
Next, a release layer is applied to the substrate film obtained by the above method. The timing of providing the release layer on the surface of the base film is not particularly limited. Either a method of applying the substrate film during the manufacturing process of the substrate film or a method of applying the substrate film wound up in a roll shape using a coater dedicated for application may be used. The application method is not particularly limited, but a reverse roll coat, a wire bar coat, a doctor blade, a gravure roll coat, an air knife coat, a rod coat, a die coat, a spray coat, an impregnated coat, or the like can be applied alone or in combination. .
(Method of measuring physical properties and method of evaluating effects)
The method for measuring characteristic values and the method for evaluating effects in the present invention are as follows.
[0075]
(1) Lamination thickness and release layer thickness of base film
Using a transmission electron microscope (H-600 manufactured by Hitachi), an ultra-thin section method (RuO ₄ (Dyeing), and the lamination interface is captured by the difference in the contrast of the TEM photograph. When one of the adjacent layers contains polyimide or particles, the interface between the layers is determined from the presence or absence of the polyimide or particles and the difference in the shape of the particles, and the lamination thickness and release layer thickness are determined.
[0076]
The magnification is usually selected depending on the thickness of the laminate to be determined, and is not particularly limited, but is suitably 10,000 to 200,000.
[0077]
(2) Polyimide content
Dissolve in a suitable solvent that dissolves both polyester and polyimide, ¹ An NMR (nuclear magnetic resonance) spectrum of the H nucleus is measured. In the obtained spectrum, the peak area intensity of the absorption corresponding to the aromatic protons in the polyester (around 8.1 ppm in PET) and the absorption corresponding to the protons of the polyimide are determined, and the molar ratio of the blend is determined from the ratio and the number of protons. calculate. Further, the weight ratio is calculated from the formula weight corresponding to the unit unit of the polymer.
[0078]
If the polyimide is polyetherimide (PEI), dissolve the film in a suitable solvent that dissolves both PET and PEI, such as hexafluoroisopropanol / chloroform; ¹ The NMR spectrum of the H nucleus is measured. In the obtained spectrum, the peak area intensities of the absorption corresponding to the aromatic proton in the polyester (around 8.1 ppm in PET) and the absorption corresponding to the aromatic proton of bisphenol A in the polyetherimide (7.0 ppm) are shown. First, the molar ratio of the blend is calculated from the ratio and the number of protons. Further, the weight ratio is calculated from the formula weight corresponding to the unit unit of the polymer.
[0079]
1) NMR measurement conditions
Apparatus: BRUKER DRX-500 (manufactured by Bruker)
Solvent: hexafluoroisopropanol / chloroform
Observation frequency: 499.8 MHz
Standard: TMS (0 ppm)
Measurement temperature: 30 ° C
Observation width: 10 KHz
Data point: 64K
Acquisition time: 4.952 seconds
pulse delay time: 3.048 seconds
Number of integration: 256 times.
[0080]
(3) Content of particles
A solvent that dissolves the polyester and the polyimide but does not dissolve the particles is selected, the polyester and the polyimide are dissolved, the particles are centrifuged from the polyester, and the ratio of the particles to the total weight of the base film (% by weight) is defined as the particle content. In some cases, a combination of infrared spectroscopy and an X-ray microanalyzer were used.
[0081]
(4) Average particle size
In the same manner as in the above evaluation method (1), using a transmission electron microscope (H-600, manufactured by Hitachi), at an accelerating voltage of 100 kV, an ultra-thin section method (RuO) was used. ₄ Staining), the section thickness of the TEM was about 100 nm, and the particle size was determined by measuring 100 or more visual fields from a TEM photograph.
[0082]
(5) Surface roughness Ra
The center line average roughness Ra (unit: nm) was measured using a high-precision thin film step measuring device ET-10 manufactured by Kosaka Laboratory. The conditions are as follows.
(Measurement condition)
Stylus tip radius: 0.5 μm
Stylus load: 5mg
Measurement length: 1.0mm
Cutoff value: 0.08mm
Scanning was performed 20 times in the film width direction, and the average was taken.
[0083]
(6) Heat shrinkage
It was measured according to JIS, C2318, and the heat shrinkage was determined by the following equation.
[0084]
Heat shrinkage (%) = [(L ₀ -L) / L ₀ ] X 100
L ₀ : Marking line interval before heat treatment
L: mark line spacing after heat treatment
The sample size was 10 mm in width and 200 mm in mark interval, and the measurement was performed at a temperature of 160 ° C. for a processing time of 30 minutes with no load.
[0085]
(7) Glass transition temperature (Tg)
The measurement was performed using a Perkin Elmer DSC (differential scanning calorimeter) type II. The measurement conditions of DSC are as follows. That is, 10 mg of a sample is set in a DSC device, melted at a temperature of 300 ° C. for 5 minutes, and then rapidly cooled in liquid nitrogen. The quenched sample is heated at a rate of 10 ° C./min, and the glass transition point Tg is detected.
[0086]
(8) Intrinsic viscosity
The value calculated from the following formula from the solution viscosity measured at 25 ° C. in orthochlorophenol is used.
[0087]
ηsp / C = [η] + K [η] 2 · C
Here, ηsp = (solution viscosity / solvent viscosity) −1, C is the weight of dissolved polymer per 100 ml of solvent (g / 100 ml, usually 1.2), and K is the Huggins constant (0.343). The solution viscosity and the solvent viscosity were measured using an Ostwald viscometer.
[0088]
(9) Oligomer inhibition
The film is attached to a mold and heated at 160 ° C. for 1 hour in a hot air drier to forcibly precipitate low molecular weight substances on the film surface. This surface is subjected to aluminum evaporation and observed with a differential interference microscope at a total magnification of 400. The total area s of the precipitated low molecular weight substance and the photograph observation area S on the photograph are measured, and the ratio of the oligomer precipitation area to the film surface area is determined. This was observed in 50 visual fields, and the average value was taken as the oligomer precipitation index.
Oligomer index = (s / S) × 100
The evaluation judgment was as follows.
[0089]
Oligomer index 0 to less than 0.5: ○
△ 0.5 to less than 1.0: △
〃 1.0 or more: ×
好 ま し い is preferable, but △ has no practical problem.
[0090]
(10) Heat resistance
The release film cut to A4 size was placed on a smooth hot plate heated to 130 ° C. for 3 minutes, and then left on a smooth metal plate at about room temperature for 3 minutes. At that time, irregularities on the surface of the laminated film, air entrapment at the interface, and the like were visually observed. The evaluation judgment was as follows.
[0091]
◎: Flatness did not change at all
：: slightly curled at the end but did not change the flatness
Δ: The flatness was deteriorated and the surface was uneven.
X: The curl was severe and many wrinkles were generated.
[0092]
(11) Processing suitability
Observation of film tearing / tearing during handling at the time of slitting, cutting, coating, laminating, peeling, and the like was performed, and workability was evaluated from the frequency of tearing / tearing.
[0093]
：: When there is no tearing or tearing of the film
Δ: Film tearing rarely occurs, but there is no particular problem without reducing productivity.
X: When film tearing occurs frequently.
[0094]
(12) Releasability
A 19 mm wide acrylic pressure-sensitive adhesive tape (Nitto Polyester Tape 31B manufactured by Nitto Denko Corporation) was attached to the release layer surface of the release film so as to have a length of 200 mm, and pressed with a rubber roller (linear pressure: 2 kg / cm). . The stress when this adhesive tape was peeled at a peeling angle of 180 ° at a pulling rate of 300 mm / min in an atmosphere of 25 ° C. and 55% RH was determined. The measurement was an average value of 10 measurements.
[0095]
When the peeling force was 25 g / 19 mm or less, the releasability was evaluated as ○, and when the peeling force exceeded 25 g / 19 mm, the releasability was evaluated as ×.
[0096]
【Example】
Next, the present invention will be described based on examples, but is not necessarily limited thereto.
[0097]
Synthesis example
First, 0.1 part by weight of magnesium acetate tetrahydrate was added to 194 parts by weight of dimethyl terephthalate and 124 parts by weight of ethylene glycol by a usual method, and transesterification was performed at 140 to 230 ° C. while distilling methanol. . Next, an ethylene glycol solution of 0.05 parts by weight of trimethyl phosphate and 0.05 parts by weight of antimony trioxide were added, and the mixture was stirred for 5 minutes. Then, while stirring the low polymer at 30 rpm, the reaction system was heated to 230 to 290C. C. and the pressure was lowered to 0.1 kPa. The time required to reach the final temperature and the final pressure was 60 minutes. When the polymerization reaction was carried out for 3 hours and a predetermined stirring torque was reached, the reaction system was purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged in cold water in a strand form, and immediately cut to obtain polyethylene terephthalate pellets 1 ( An intrinsic viscosity of 0.65) was obtained. 50% by weight of this pellet and 50% by weight of a polyetherimide pellet "Ultem 1010" (registered trademark, manufactured by GE Plastics Co., Ltd.) were fed to a vented twin-screw extruder heated to 290 ° C. The mixture was melt-extruded at a shear rate of 100 sec-1 and a residence time of 1 minute to obtain a polyester pellet 2 containing 50% by weight of polyetherimide. The resulting chip was transparent and only a single glass transition temperature was observed.
[0098]
In addition, during the polymerization of polyethylene terephthalate, 4% by weight of particles (wet silica having an average particle size of 1.5 μm) were added and polymerized to obtain pellets 3 (intrinsic viscosity: 0.65).
[0099]
Example 1
The polyethylene terephthalate pellets 1 containing no particles obtained in the synthesis example, the pellets 2 containing 50% by weight of polyetherimide, and the pellets 3 containing the particles were mixed at a ratio of 6.8: 3: 0.2. After mixing and vacuum drying at 180 ° C. for 4 hours, the mixture was supplied to a usual melt extruder and melt-extruded at 295 ° C. This was wound around a casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched film.
[0100]
This unstretched film was stretched 3.4 times in the longitudinal direction at 105 ° C. This stretching was performed using the difference in peripheral speed between two sets of rolls. While holding both ends of the obtained uniaxially stretched film with clips, the film was guided to a preheating zone at 95 ° C., and subsequently stretched 3.6 times in the width direction in a heating zone at 115 ° C. Further, the film was subjected to a heat treatment for 5 seconds while continuously performing a relaxation treatment of 10% in the width direction in a heat treatment zone at 230 ° C., and the edge portions at both ends of the film were trimmed to obtain a biaxially oriented film having a film thickness of 38 μm. .
[0101]
After performing a corona discharge treatment in air on the surface of the film thus obtained, KS854 (manufactured by Shin-Etsu Chemical Co., Ltd.) is used as a release agent on the corona discharge treatment surface, and the thickness after drying and curing is 0%. The coating was dried by an offset gravure coater to a thickness of 0.2 μm to obtain a release film of the present invention.
[0102]
The release film thus obtained had a release force of 16 g / 19 mm, and had good release properties. In addition, the film was excellent in film handling properties at the time of slitting, cutting, coating, laminating, peeling, and the like, and no breakage or tearing of the film occurred, and the workability was good. This release film had excellent properties as shown in Table 1.
[0103]
Example 2
Pellets 1, 2 and 3 obtained in the synthesis examples were mixed at a ratio of 7.8: 2: 0.2, and an unstretched film was produced in the same manner as in Example 1. After stretching this unstretched film 3.6 times in the longitudinal direction at 100 ° C., it was stretched 3.7 times in the width direction at 100 ° C. Further, after a continuous heat treatment at 230 ° C. for 8 seconds, a 4% relaxation treatment was performed in the width direction, and the edge portions at both ends of the film were trimmed, and the biaxially oriented film was wound.
[0104]
Next, the wound biaxially oriented film is heated for 25 seconds at a film tension of 1.0 MPa in a heating zone having a preheating temperature of 120 ° C., a main heating temperature of 175 ° C., and a cooling temperature of 140 ° C. by an infrared heater. A substrate film of the present invention having a thickness of 38 μm was obtained. After performing a corona discharge treatment on the film surface obtained in the air in the air, a fluorine-containing acrylic resin “Freaction” RBX-725NF (Neos Corporation) is used as a fluorine-containing resin for a release coating agent on the corona discharge treated surface. "Crytox" 157-FSM (manufactured by DuPont) as a fluorinated oil, and "Fluorinert" FC-77 (manufactured by 3M) as a diluting solvent in a composition having a weight solids ratio of 20:80. A coating material having a concentration of 3% by weight uniformly dispersed was applied by a bar coating method and dried at 120 ° C. for 1 minute to obtain a release film having a release layer thickness of 0.35 μm.
[0105]
The obtained release film had a release force of 7 g / 19 mm and had good release properties. In addition, the film was excellent in handleability at the time of slitting, cutting, coating, laminating, peeling, and the like, and the workability was good without any breakage or tearing of the film. This release film had excellent properties as shown in Table 1.
[0106]
Example 3
Paint composition is vegetable wax (100 parts by weight) {hydrogenated rosin / α-, β-substituted ethylene (α-substituent: carboxyl, β-substituent: methyl) adduct] -alkyl (C6) poly (repeat unit: 5) One part by weight of a nonionic surfactant, a phosphoric acid ester (butoxyethyl compound), ammonium oleate, and 2-amino-2-methylpropanol were added to make the alcohol ester compound a water-dispersed paint. Then, the mixture was vigorously stirred in water, and further, an ultrasonic dispersion machine was used to prepare an aqueous dispersion having a total solid content of 1% by weight. In the same manner as in Example 1, one surface of the uniaxially stretched film stretched 3.4 times in the longitudinal direction was subjected to a corona discharge treatment, and the water-dispersed coating material having the above composition was inline-coated on the surface by a bar coating method. The coated uniaxially stretched film is guided to a tenter and dried in a preheating step at 110 ° C., then stretched 4 times in the width direction while heating to 125 ° C., and then heat-set at 225 ° C. A film having a mold layer thickness of 0.05 μm was obtained. Thereafter, in the same manner as in Example 2, a release film having a film thickness of 38 μm was obtained in a heating zone of a preheating temperature of 100 ° C. using an infrared heater, a main heating temperature of 130 ° C., and a cooling temperature of 120 ° C.
[0107]
The obtained release film had a release force of 20 g / 19 mm and had good release properties. In addition, the film was excellent in handleability at the time of slitting, cutting, coating, laminating, peeling, and the like, and the workability was good without any breakage or tearing of the film. This release film had excellent properties as shown in Table 1.
[0108]
Example 4
The polyethylene terephthalate pellets 1 obtained in the synthesis example and the pellets 2 containing 50% by weight of polyetherimide were mixed at a ratio of 2: 8 (polymer A) and dried under vacuum at 180 ° C. for 4 hours. And melted at 295 ° C. Further, the pellets 1, 2 and 3 were mixed at a ratio of 9: 0.5: 0.5 (polymer B), dried in vacuum at 180 ° C. for 4 hours, and then supplied to a usual melt extruder B. And melted at 285 ° C. These polymers were filtered by an ordinary method, and a two-layer unstretched film of a polymer A layer / polymer B layer was obtained by a rectangular merging block (feed block) for two layers. The thickness of each layer was adjusted by adjusting the rotation speed of a gear pump installed in each line to control the amount of extrusion. A biaxially oriented film having a film thickness of 38 μm (layer A / layer B = 2/36 μm) was obtained from this unstretched film in the same manner as in Example 1. Next, this biaxially oriented film was heated at a film tension of 1.0 MPa for 15 seconds in a heating zone of a preheating temperature of 120 ° C., a main heating temperature of 180 ° C., and a cooling temperature of 130 ° C. by an infrared heater, and a film thickness of 38 μm. A substrate film of the present invention was obtained. A release layer was provided on the layer A side of the substrate film in the same manner as in Example 1 to obtain a release film.
[0109]
The obtained release film had a release force of 18 g / 19 mm and had good release properties. In addition, the film was excellent in film handling properties at the time of slitting, cutting, coating, laminating, peeling, and the like, and no breakage or tearing of the film occurred, and the workability was good. This release film had excellent properties as shown in Table 1.
[0110]
Example 5
The configuration of the base film was a three-layer configuration of A / B / A. In the B layer, 90% by weight of polyethylene-2,6-naphthalate (PEN) pellets obtained by a usual method and 10% by weight of polyetherimide (PEI) pellets were mixed and heated to 300 ° C. The mixture was supplied to a vented twin-screw kneading extruder, melt-extruded, and PEN / PEI pellets containing 10% by weight of polyetherimide were used. This was vacuum-dried at 180 ° C. for 4 hours, and then supplied to a usual melt extruder B to be melted at 305 ° C. The same layer as the polymer of Example 2 was used for the A layer, dried, supplied to the melt extruder A and melted at 290 ° C. These molten polymers were filtered by a usual method, and A / B / A was laminated in a rectangular confluence block (feed block) for three layers. This was wound around a casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched film.
[0111]
This unstretched film was stretched 3.8 times in the longitudinal direction at 130 ° C. and 4.5 times in the width direction in a heating zone at 130 ° C. in the width direction. Further, the film was heat-treated for 5 seconds while continuously performing a 10% relaxation treatment in a heat treatment zone at 230 ° C., and the edge portions at both ends of the film were trimmed to obtain a film having a thickness of 38 μm and (A / B / A = 2 / (34/2 μm). This biaxially oriented laminated film was annealed at 180 ° C. in the same manner as in Example 4 to provide a release layer to obtain a release film.
[0112]
The obtained release film had a release force of 17 g / 19 mm and had good release properties. The film was torn once each at the start of the edge trimming of both ends of the film and during the sampling for the peeling test. However, there was no particular problem, and the film was easy to handle. This release film had excellent properties as shown in Table 1.
[0113]
Comparative Example 1
Except that the polyetherimide-containing pellet 2 is not mixed, and the stretching temperature in the longitudinal direction is 93 ° C., the stretching ratio is 3.6 times, and the stretching temperature in the width direction is 95 ° C., the stretching ratio is 3.7 times, A release film was obtained in the same manner as in Example 1.
[0114]
The obtained release film had a release force of 24 g / 19 mm and had good releasability, but had a large heat shrinkage and poor heat resistance and oligomer deterrence.
[0115]
Comparative Example 2
Using a polymer to which 0.08 weight of particles (wet silica having an average particle size of 1.0 μm) was added at the time of PEN polymerization, melt extrusion was performed at an extrusion temperature of 300 ° C. using a polymer containing no polyimide. This was stretched 3.4 times in the longitudinal direction at 128 ° C and 3.6 times in the width direction in a heating zone at 125 ° C in the same manner as in Example 1. Further, a heat treatment was performed for 5 seconds while continuously performing a 10% relaxation treatment in a heat treatment zone at 230 ° C., and a release layer was further provided to obtain a release film having a film thickness of 38 μm.
[0116]
The obtained release film had a release force of 19 g / 19 mm and had good releasability. However, this release film was torn at the time of slitting and winding at the time of winding a winder at the time of coating. there were. In addition, tearing and tearing frequently occurred during sampling cutting, and handling was poor. In addition, oligomer deterrence was poor.
[0117]
[Table 1]

[0118]
【The invention's effect】
The release film obtained by the present invention is excellent in heat resistance and oligomer deterrence, so that even when subjected to a high-temperature heat treatment in a processing step for use in various applications, the flatness is not deteriorated and oligomer precipitation is significantly increased. Can be suppressed. Therefore, by taking advantage of these characteristics, a backing sheet such as an adhesive label seal or an adhesive tape, an adhesive protection sheet, a molded resin surface protection sheet, or a liquid crystal display panel protection sheet such as a polarizing plate or a retardation plate used for a liquid crystal display. , Which can be suitably used for protecting protective sheets for building materials, etc., and for producing synthetic leather such as PVC and urethane, for producing pressure-sensitive adhesive films, for carbon fiber prepregs, for producing ceramic sheets and multilayer ceramic capacitors. It can be suitably used as various industrial materials for manufacturing various molded products such as circuit boards for high density mounting and the like.

Claims (8)

A release film characterized in that a release layer is provided on at least one surface of a base film made of a resin composition containing polyester and polyimide. The release film according to claim 1, wherein the base film is a laminated film having at least two layers, at least one of which is a layer made of a resin composition containing polyester and polyimide. The release film according to claim 1 or 2, wherein the polyester in the base film is polyethylene terephthalate polyethylene 2,6-naphthalate, or a copolymer or modified product thereof. The release film according to any one of claims 1 to 3, wherein the polyimide in the base film is polyetherimide, and the film layer contains the polyetherimide in an amount of 5 to 50% by weight. The release film according to any one of claims 1 to 4, wherein the base film contains 0.005 to 30% by weight of particles having an average diameter of 0.01 to 5 µm. The center line average roughness (Ra) of at least one surface of the substrate film is 1 to 100 nm, and the difference of the center line average roughness (Ra) of the front and back surfaces of the substrate film is 0 to 100 nm. 5. The release film according to any one of 5. The release film according to any one of claims 1 to 6, wherein a heat shrinkage of the base film after heating at 150 ° C for 30 minutes is 0.7% or less. The release layer contains at least one selected from a silicone resin, a fluorine resin, an acrylic resin, and a wax as a main component, and has a release layer thickness of 0.01 to 20 μm. Item 8. The release film according to any one of Items 1 to 7.