JP2004177718A - Release film - Google Patents

Abstract

An object of the present invention is to provide a release film for protecting a pressure-sensitive adhesive layer used in the production of a liquid crystal component, which has a minimum amount of oligomer precipitation, has good antistatic properties and transparency, and is easy to inspect with an optical evaluation.
A film used in the production of a liquid crystal component, which is a release film in which a coating layer containing a compound having a nitrogen element and a binder polymer and a release layer are sequentially provided on one surface of a polyester film. A release film for protecting an adhesive layer, which satisfies the formulas (1) to (4) at the same time. OL ≦ 2.0 (1) R ≦ 1 × 10 ¹³ (2) TL ≧ 80 (3) TL (H) ≦ 8 (4) (in the above formula, OL represents the release film after heat treatment. The amount of oligomers extracted from the release layer surface by DMF, R is the surface resistivity of any one of the release films, TL is the total light transmittance of the release film, and TL (H) is orthogonal polarization. Represents the total light transmittance of the laminate with the release film between the plates)
[Selection diagram] None

Description

【００２４】
【化２】

【００２５】
上記式（Ｉ）および（ＩＩ）中、Ｒ^１、Ｒ^２は、それぞれ独立して、アルキル基、フェニル基等であり、これらのアルキル基、フェニル基が以下に示す基で置換されていてもよい。
【００２６】
置換可能な基は、例えば、ヒドロキシル基、アミド基、カルボ低級アルコキシ基、低級アルコキシ基、チオフェノキシ基、シクロアルキル基、トリ−（低級アルキル）アンモニウム低級アルキル基等であり、ニトロ基はアルキル基上でのみ、またハロゲン基はフェニル基上でのみ置換可能である。また、Ｒ^１およびＲ^２は化学的に結合していてもよく、例えば、−（ＣＨ_２）_ｍ−（ｍ＝２〜５の整数）、−ＣＨ（ＣＨ_３）−ＣＨ（ＣＨ_３）−、−ＣＨ＝ＣＨ−ＣＨ＝ＣＨ−、−ＣＨ＝ＣＨ−ＣＨ＝Ｎ−、−ＣＨ＝ＣＨ−Ｎ＝ＣＨ−、−（ＣＨ_２）_２Ｏ（ＣＨ_２）_２、（ＣＨ_２）_２Ｏ（ＣＨ_２）_２等が挙げられる。上記式中のＸ⁻は、Ｃｌ⁻、Ｂｒ⁻、１／２ＳＯ_４ ^２−、または１／３ＰＯ_４ ^３−等の無機酸残基、ＣＨ_３ＳＯ_４ ⁻、Ｃ_２Ｈ_５ＳＯ_４ ⁻のスルホン酸残基を示す。
【００２７】
本発明における（Ｉ）のポリマーは、例えば、下記式（ＩＩＩ）で表される化合物を、ラジカル重合触媒を用いて環化重合させることにより得られる。
【００２８】
【化３】

【００２９】
また、前記（ＩＩ）式のポリマーは、上記（ＩＩＩ）式の化合物を、二酸化イオウを溶媒とする系で環化重合させることにより得られる。重合は、溶媒として水あるいはメタノール、エタノール、イソプロパノール、ホルムアミド、ジオキサン、アセトニトリル、二酸化イオウなどの極性溶媒中で過酸化水素、ベンゾイルパーオキサイド、第３級ブチルパーオキサイド等の重合開始剤により、公知の方法で実施できるが、これらに限定されるものではない。
【００３０】
本発明における主鎖にピロリジウム環を有するポリマーは、上記（ＩＩＩ）式の化合物と重合性のある炭素−炭素不飽和結合を有する化合物を共重合成分としてもよい。
本発明における主鎖にピロリジウム環を有するポリマーの分子量は、好ましくは５００〜１００００００、さらに好ましくは１０００〜５０００００である。ポリマーの分子量が５００未満の場合は、帯電防止効果はあるものの、塗膜の強度が弱かったり、ブロッキングしやすかったりする傾向がある。ポリマーの分子量が１００００００より高い場合は、塗布液の粘度が高くなり、取扱い性や塗布性が悪化する傾向がある。
【００３１】
塗布層中に含有される窒素元素を有する化合物の含有量は特に限定される訳ではないが、好ましくは１０〜９９重量％、さらに好ましくは２０〜９５重量％の範囲がよい。
さらに本発明における離型フィルムを構成する塗布層中には塗布層の塗膜耐久性、造膜性等を考慮して、バインダーポリマーを含有する必要がある。
塗布層に含有されるバインダーポリマーの具体例として、ポリビニルアルコール（以下、ＰＶＡと略記する場合がある。）、ポリアクリルアミド、ポリアルキレングリコール、ポリアルキレンイミン、メチルセルロース、ヒドロキシセルロース、でんぷん類、ポリウレタン、ポリエステル、ポリアクリレート、塩素系ポリマー（ポリ塩化ビニル、塩化ビニル酢酸ビニル共重合体等）、ポリオレフィン等が挙げられる。それらの中でも、塗布層を塗布延伸法により塗設する場合にはノニオン系、カチオン系、両性系の水溶液または水分散体として使用可能な有機ポリマーが挙げられ、好ましくはオリゴマー析出防止性向上の観点からも、上述の窒素元素を有する化合物との好適な組み合わせとして、ポリビニルアルコールを含有するのがよい。
【００３２】
塗布層中に含有されるポリビニルアルコール等のバインダーポリマーの含有量は特に限定される訳ではないが、好ましくは１０〜９０重量％、さらに好ましくは１０〜８０重量％の範囲がよい。バインダーポリマーの含有量が１０重量％未満では塗布層の造膜性が不十分になる等の不具合を生じる場合がある。
また、本発明で用いるＰＶＡの重合度は特に限定されるわけではないが、通常１００以上、好ましくは３００〜４００００のものが用途上好適に用いられる。
一方、ＰＶＡのけん化度は特に限定されるわけではないが、７０モル％以上、好ましくは８０モル％以上、９９．９モル％以下のものが好適に用いられ、具体例としては酢酸ビニルけん化物等が挙げられる。
【００３３】
さらに塗布層には架橋剤を併用してもよく、具体例としてはメチロール化またはアルキロール化した尿素系、メラミン系、グアナミン系、アクリルアミド系、ポリアミド系化合物、エポキシ化合物、アジリジン化合物、ブロックポリイソシアネート、シランカップリング剤、チタンカップリング剤、ジルコ−アルミネートカップリング剤等が挙げられる。これらの架橋成分は、バインダーポリマーと予め結合していてもよい。
また、塗布層の固着性、滑り性改良を目的として、無機系粒子を含有してもよく、具体例としてはシリカ、アルミナ、カオリン、炭酸カルシウム、酸化チタン、バリウム塩等が挙げられる。さらに必要に応じて消泡剤、塗布性改良剤、増粘剤、有機系潤滑剤、有機系高分子粒子、酸化防止剤、紫外線吸収剤発泡剤、染料等が含有されてもよい。
【００３４】
本発明における離型フィルムを構成する塗布層の塗布量（乾燥後）は通常０．０１〜１ｇ／ｍ^２、好ましくは０．０３〜０．５ｇ／ｍ^２の範囲がよい。塗布量が０．０１ｇ／ｍ^２未満の場合には、塗布厚みの均一性が不十分な場合があり、一方、１ｇ／ｍ^２を超えて塗布する場合には、滑り性低下等の不具合を生じる場合がある。
本発明において、離型フィルムを構成する塗布層を設ける方法は後述する離型層を設ける場合と同様にリバースグラビアコート、グラビアコート、バーコート、ダイコート等、従来公知の塗工方式を用いることができる。
【００３５】
なお、塗布層に関して、好ましくは上述の塗布延伸法（インラインコーティング法）によりポリエステルフィルム上に設けられるのがよい。
本発明の離型フィルムを構成する離型層中には硬化型シリコーン樹脂を含有させると離型性が良好となるので好ましい。硬化型シリコーン樹脂を主成分とするタイプでもよいし、ウレタン樹脂、エポキシ樹脂、アルキッド樹脂等の有機樹脂とのグラフト重合等による変性シリコーンタイプ等を使用してもよい。
硬化型シリコーン樹脂の種類としては付加型・縮合型・紫外線硬化型・電子線硬化型・無溶剤型等、何れの硬化反応タイプでも用いることができる。
具体例を挙げると、信越化学工業（株）製ＫＳ−７７４、ＫＳ−７７５、ＫＳ−７７８、ＫＳ−７７９Ｈ、ＫＳ−８４７Ｈ、ＫＳ−８５６、Ｘ−６２−２４２２、Ｘ−６２−２４６１、ダウ・コーニング・アジア（株）製ＤＫＱ３−２０２、ＤＫＱ３−２０３、ＤＫＱ３−２０４、ＤＫＱ３−２０５、ＤＫＱ３−２１０、東芝シリコーン（株）製ＹＳＲ−３０２２、ＴＰＲ−６７００、ＴＰＲ−６７２０、ＴＰＲ−６７２１、東レ・ダウ・コーニング（株）製ＳＤ７２２０、ＳＤ７２２６、ＳＤ７２２９、ＬＴＣ７５０Ａ等が挙げられる。さらに離型層の剥離性等を調整するために、剥離コントロール剤を併用してもよい。
【００３６】
本発明の離型フィルムを構成する塗布層上に離型層を設ける方法として、リバースグラビアコート、グラビアコート、バーコート、ダイコート、カーテンコート等、従来公知の塗工方式を用いることができる。
離型層の塗工量は塗工性の面から、通常０．０１〜１ｇ／ｍ^２、好ましくは０．０３〜０．５ｇ／ｍ^２の範囲である。塗工量が０．０１ｇ／ｍ^２未満の場合、塗工性の面より安定性に欠け、均一な塗膜を得るのが困難になる場合がある。一方、１ｇ／ｍ^２を超えて厚塗りにすると離型層自体の塗膜密着性、硬化性等が低下する場合がある。
【００３７】
本発明における離型フィルムに関して、離型層が設けられていない面には接着層、帯電防止層、オリゴマー析出防止層等の塗布層を設けてもよく、ポリエステルフィルムにはコロナ処理、プラズマ処理等の表面処理を施してもよい。
本発明の離型フィルムの全光線透過率（ＴＬ）は８０％以上であることが用途上、必要である。ＴＬが８０％未満の場合、透明性が不十分となり、光学的評価を伴う検査工程においては異物の混入を見落とし易くなる等の不具合を生じるようになる。
さらに本発明の離型フィルムを、直交させた偏光板の間に挟んで積層状態としたときの全光線透過率（ＴＬ（Ｈ））は８％以下である必要があり、好ましくは５％以下、さらに好ましくは２％以下である。ＴＬ（Ｈ）が８％を超える場合、液晶偏光板の検査工程において、離型フィルムを構成するポリエステルフィルムの光学的異方性起因により、偏光ムラ等の不具合を生じるようになる。
【００３８】
また、本発明の離型フィルムは用途上、ポリエステルフィルム面内の主配向軸のＭＤ方向に対する角度（θ_３）が７０度以上を満足するのが好ましい。θ_３は好ましくは８０度以上がよい。θ_３が７０度未満の場合、光学的評価を伴う検査工程においては異物の混入を見落としやすくなり、検査時に離型フィルムを一旦剥離し、検査終了後に再度貼付しなければならない等の不具合を生じる場合がある。
本発明の離型フィルムを構成する離型層の残留接着率は、貼り合わせる相手方である粘着剤層へのシリコーン移行あるいは転着を抑制するために、９０％以上であることが好ましく、さらに好ましくは９５％以上がよい。残留接着率が９０％未満の場合、製造工程において搬送用ロールのロール表面にシリコーン移行成分が転着したり、離型面と接する粘着剤層の粘着力が低下する等の不具合を生じたりする場合がある。
【００３９】
【実施例】
以下、本発明を実施例によりさらに詳細に説明するが、本発明はその要旨を越えない限り、以下の実施例に限定されるものではない。また、本発明で用いた測定法は次のとおりである。
【００４０】
（１）ポリエステルの固有粘度の測定
ポリエステルに非相溶な他のポリマー成分および顔料を除去したポリエステル１ｇを精秤し、フェノール／テトラクロロエタン＝５０／５０（重量比）の混合溶媒１００ｍｌを加えて溶解させ、３０℃で測定した。
【００４１】
（２）平均粒径（ｄ_５０：μｍ）の測定
遠心沈降式粒度分布測定装置（株式会社島津製作所社製ＳＡ−ＣＰ３型）を使用して測定した等価球形分布における積算（重量基準）５０％の値を平均粒径とした。
【００４２】
（３）離型フィルムの離型層表面から抽出されるオリゴマー量（ＯＬ）の測定
上部が開放され、底辺の面積が２５０ｃｍ^２となるように熱処理後（１８０℃、１０分間）の離型フィルムを折り、四角の箱を作成する。塗布層を設けている場合は塗布層面が内側となるようにする。
次いで、上記の方法で作成した箱の中にＤＭＦ１０ｍｌを入れて３分間放置した後、ＤＭＦを回収する。回収したＤＭＦを液体クロマトグラフィー（島津製作所製：ＬＣ−７Ａ）に供給してＤＭＦ中のオリゴマー量を求め、この値を、ＤＭＦを接触させたフィルム面積で割って、フィルム表面オリゴマー量（ｍｇ／ｍ^２）とする。
ＤＭＦ中のオリゴマー量は、標準試料ピーク面積と測定試料ピーク面積のピーク面積比より求めた（絶対検量線法）。
標準試料の作成は、予め分取したオリゴマー（環状三量体）を正確に秤量し、正確に秤量したＤＭＦに溶解し作成した。標準試料の濃度は０．００１〜０．０１ｍｇ／ｍｌの範囲が好ましい。
【００４３】
なお、液体クロマトグラフの条件は下記のとおりとした。
移動相Ａ：アセトニトリル
移動相Ｂ：２％酢酸水溶液
カラム：三菱化学（株）製『ＭＣＩ ＧＥＬ ＯＤＳ １ＨＵ』
カラム温度：４０℃
流速：１ｍｌ／分
検出波長：２５４ｎｍ
【００４４】
（４）離型フィルムの全光線透過率（ＴＬ）の測定
ＪＩＳ−Ｋ−７１０５に準じて日本電色工業社製積分球式濁度計「ＮＤＨ−３００Ａ」により、離型フィルムの全光線透過率（％）を測定した。
【００４５】
（５）離型フィルムにおける、フィルム面内の主配向軸のＭＤ方向に対する角度（θ_３）の測定
カールツァイス社製偏光顕微鏡を用いて、離型フィルムの配向を観察し、ポリエステルフィルム面内の主配向軸の方向がポリエステルフィルムのＭＤ方向に対して何度傾いているかをフィルム幅方向に均等に１０点測定し、それらの測定値の最大値をθ_３とした。
なお、測定上、主配向軸が９０度を超えた場合にはその補角を主配向軸のＭＤ方向に対する角度とした。
【００４６】
（６）直交偏光板間に離型フィルムを挟んだときの全光線透過率（ＴＬ（Ｈ））の測定
ＪＩＳ−Ｋ−７１０５に準じて日本電色工業社製積分球式濁度計「ＮＤＨ−３００Ａ」により、直交させた偏光板（日東電工製：偏光率９９．９９％）の間に離型フィルムを挟み、積層体の状態での全光線透過率（％）を測定した。
ＴＬ（Ｈ）値が小さいほど、偏光ムラ等が生じにくく、偏光板の検査が容易に行えるようになる。
【００４７】
（７）離型フィルムの残留接着率の評価
▲１▼残留接着力
試料フィルムのシリコーン面に日東電工（製）Ｎｏ．３１Ｂ粘着テープを２ｋｇゴムローラーにて１往復圧着し、１００℃で１時間加熱処理する。次いで、圧着したサンプルから試料フィルムを剥がし、Ｎｏ．３１Ｂ粘着テープをＪＩＳ−Ｃ−２１０７（ステンレス板に対する粘着力、１８０°引き剥がし法）の方法に準じて接着力を測定する。これを残留接着力とする。
【００４８】
▲２▼基礎接着力
残留接着力の場合と同じテープ（Ｎｏ．３１Ｂ）を用いてＪＩＳ−Ｃ−２１０７に準じてステンレス板に粘着テープを圧着して、同様の要領にて測定を行う。この時の値を基礎接着力とする。これらの測定値を用いて、下記式に基づいて残留接着率を求める。
残留接着率（％）＝（残留接着力）×１００／（基礎接着力）
なお、測定は２０±２℃、６５±５％ＲＨにて行う。
【００４９】
（８）離型フィルムの剥離力（Ｆ）の評価
測定試料の離型層に両面粘着テープ（日東電工製「Ｎｏ．５０２」）の片面を貼り付けた後、５０ｍｍ×３００ｍｍのサイズにカットした後、室温にて１時間放置後の剥離力を測定する。剥離力は、引張試験機（（株）インテスコ製「インテスコモデル２００１型」）を使用し、引張速度３００ｍｍ／分の条件下、１８０°剥離を行った。
【００５０】
（９）離型フィルムの帯電防止性（Ｒ）の評価
日本ヒューレット・パッカード社製の測定電極であるＨＰ１６００８Ｂ（商品名）を２３℃、５０％ＲＨ雰囲気下にて測定試料を設置し、１００Ｖの電圧を印加し、同社高抵抗計ＨＰ４３３９Ｂ（商品名）で表面固有抵抗を測定した。
【００５１】
（１０）離型フィルムの消光状態評価
異物を付着させた粘着剤層を介して離型フィルムと偏光板が貼り合わされた積層体において、離型フィルムの側から光を通して見た際の消光状態の有無を観察した。
【００５２】
（１１）離型フィルムの検査容易性評価
異物を付着させた粘着剤層を介して離型フィルムと偏光板が貼り合わされた 積層体において、離型フィルムの側から光を通して見た際の異物の見えやすさを下記判定基準により評価した。
《判定基準》
良好：検査可能（実用上問題ないレベル）
やや不良：検査困難な場合がある（実用上問題あるレベル）
不良：検査不可能（実用上問題あるレベル）
【００５３】
〈ポリエステルの製造〉
製造例１（ポリエチレンテレフタレートＡ１）
ジメチルテレフタレート１００部、エチレングリコール６０部および酢酸マグネシウム・４水塩０．０９部を反応器にとり、加熱昇温すると共にメタノールを留去し、エステル交換反応を行い、反応開始から４時間を要して２３０℃に昇温し、実質的にエステル交換反応を終了した。次いで、エチレングリコールスラリーエチルアシッドフォスフェート０．０４部、三酸化アンチモン０．０３部、平均粒径０．２５μｍのシリカ粒子を０．３部添加した後、１００分で温度を２８０℃、圧力を１５ｍｍＨｇに達せしめ、以後も徐々に圧力を減じ、最終的に０．３ｍｍＨｇとした。４時間後、系内を常圧に戻し、固有粘度０．６１のポリエチレンテレフタレートＡ１を得た。
【００５４】
製造例２（ポリエチレンテレフタレートＡ２）
製造例１において、平均粒径０．２５μｍのシリカ粒子を０．３部添加する代わりに平均粒径０．２７μｍの酸化チタン粒子を１部添加する以外は製造例１と同様にしてポリエチレンテレフタレートＡ２を得た。
【００５５】
〈ポリエステルフィルムの製造〉
製造例３（ポリエステルフィルムＦ１）
製造例１で製造したポリエチレンテレフタレートＡ１を１８０℃で４時間、不活性ガス雰囲気中で乾燥し、溶融押出機により２９０℃で溶融し、口金から押出し静電印加密着法を用いて表面温度を４０℃に設定した冷却ロール上で冷却固化して未延伸シートを得た。得られたシートを８５℃で３．５倍縦方向に延伸した。
次いで、下記組成からなる塗布剤を塗布した後、フィルムをテンターに導き１００℃で３．７倍横方向に延伸した後、２３０℃にて熱固定を行い、中央部１０００ｍｍ幅のみ採取し、塗工量が０．０５ｇ／ｍ^２（乾燥後）の塗布層が設けられた、厚さ２５μｍのＰＥＴフィルムＦ１を得た。
【００５６】
《化合物例》
▲１▼窒素元素を有する化合物（Ａ）：主鎖にピロリジウム環を有する化合物
（第一工業製薬社製：シャロールＤＣ−３０３Ｐ）
▲２▼窒素元素を有する化合物（Ｂ）：ポリトリメチルアミノエチルメタクリレート４級化物
▲３▼アクリル系樹脂（Ｃ）：アクリル酸アルキルエステルとメタクリル酸アルキルエステルの共重合体（Ｔｇ：約４０℃）（日本カーバイド工業製：ニカゾール）
▲４▼ＰＶＡ系樹脂（Ｄ）：けん化度＝８８モル％、重合度＝５００のポリビニルアルコール
▲５▼架橋性化合物（Ｅ）：メトキシメチロールメラミン（大日本インキ化学工業社製：ベッカミン）
▲６▼架橋性化合物（Ｆ）：ジルコニウム化合物（第一稀元素化学工業社製：ジルコゾールＺＣ−２）
▲７▼粒子（Ｇ）：平均粒径０．０５μｍのシリカゾル
【００５７】
《塗布剤組成》
窒素元素を有する化合物（Ａ）：８５重量％、ＰＶＡ系樹脂（Ｄ）：１０重量％、粒子（Ｇ）：５重量％
【００５８】
製造例４（ＰＥＴフィルムＦ２）〜製造例８（ＰＥＴフィルムＦ６）
製造例２において、塗布剤組成を下記表１の塗布剤組成に変更する以外は製造例２と同様にしてＰＥＴフィルムＦ２〜ＰＥＴフィルムＦ６を得た。このフィルムの特性を下記表１に示す。
【００５９】
製造例９（ＰＥＴフィルムＦ７）
製造例３において、ポリエチレンテレフタレートＡ１の代わりにポリエチレンテレフタレートＡ２を用いる以外は製造例３と同様にしてＰＥＴフィルムＦ７を得た。このフィルムの特性を下記表１に示す。
【００６０】
製造例１０（ＰＥＴフィルムＦ８）
製造例３において、端部１０００ｍｍ幅と採取位置が異なる以外は製造例３と同様にして製造し、ＰＥＴフィルムＦ８を得た。このフィルムの特性を下記表１に示す。
【００６１】
製造例１１（ＰＥＴフィルムＦ９）
製造例３において採取した中央部１０００ｍｍ幅と製造例９において採取した端部１０００ｍｍ幅との間の部分にて１０００ｍｍ幅を採取する以外は製造例３と同様にして製造し、ＰＥＴフィルムＦ９を得た。このフィルムの特性を下記表１に示す。
【００６２】
【表１】

【００６３】
実施例１
製造例３で得られたＰＥＴフィルムＦ１に下記離型剤組成からなる離型層を塗布量（乾燥後）が０．１ｇ／ｍ^２になるように設け、離型フィルムを得た。この離型フィルムの特性を下記表２に示す。
《離型剤組成》
硬化型シリコーン樹脂：（ＫＳ−８４７Ｈ：信越化学製 固形分濃度３０％）９９重量％
硬化剤：（ＰＬ−５０Ｔ：信越化学製 固形分濃度１％）１重量％
上記離型剤をＭＥＫ／トルエン混合溶媒（混合比率は１：１）で希釈し、濃度１．５重量％の塗布液を作成した。
【００６４】
実施例２
実施例１において離型剤組成を下記組成に変更する以外は実施例１と同様にして製造し、離型フィルムを得た。この離型フィルムの特性を表２に示す。
《離型剤組成》
硬化型シリコーン樹脂：（ＫＳ−７７４：信越化学製 固形分濃度３０％）９９重量％
硬化剤：（ＰＬ−３：信越化学製 固形分濃度３０％）１重量％
上記離型剤をＭＥＫ／トルエン混合溶媒（混合比率は１：１）で希釈し、濃度１．５重量％の塗布液を作成した。
【００６５】
実施例３
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ２を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００６６】
実施例４
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ３を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００６７】
実施例５
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ４を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００６８】
実施例６
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ９を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００６９】
比較例１
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ５を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００７０】
比較例２
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ６を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００７１】
比較例３
実施例１において離型剤組成を下記組成に変更する以外は実施例１と同様にして製造し、離型フィルムを得た。この離型フィルムの特性を表２に示す。
《離型剤組成》
硬化型シリコーン樹脂：（ＫＳ−８４７Ｈ：信越化学製 固形分濃度３０％）９８重量％
硬化剤：（ＰＬ−５０Ｔ：信越化学製 固形分濃度 １％）１重量％
非反応性シリコーンオイル：（Ｘ−２２−８１９：信越化学製 比重０．９９（２５℃））１重量％
上記離型剤をＭＥＫ／トルエン混合溶媒（混合比率は１：１）で希釈し、濃度１．５重量％の塗布液を作成した。
【００７２】
比較例４
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ７を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００７３】
比較例５
実施例１において、ＰＥＴフィルムＦ１の代わりにＰＥＴフィルムＦ８を用いる以外は実施例１と同様にして離型フィルムを得た。この離型フィルムの特性を表２に示す。
【００７４】
【表２】

【００７５】
【表３】

【００７６】
【発明の効果】
本発明の離型フィルムは、液晶偏光板、位相差板等の液晶構成部材製造時に用いる粘着剤層保護用として、オリゴマー析出量が極力少なく、帯電防止性、透明性良好であり、光学的評価を伴う検査が容易な離型フィルムであり、その工業的価値は極めて高い。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a release film, specifically, as a release film for protecting an adhesive layer used in the production of a liquid crystal component such as a polarizing plate or a retardation plate used for a liquid crystal display (hereinafter sometimes abbreviated as LCD). An object of the present invention is to provide a release film which has a minimum amount of oligomer precipitation, has good antistatic properties and good transparency, and is easy to inspect with optical evaluation.
[0002]
[Prior art]
Conventionally, a release film based on a polyester film has been used for protecting an adhesive layer used in the production of liquid crystal components such as a liquid crystal polarizing plate and a retardation plate. There is a problem that oligomers cause various problems in the production process. The manufacturing process of a liquid crystal polarizing plate includes a process in which a release film and a polarizing plate are bonded together via an adhesive layer and are wound up in a roll shape, but oligomers are precipitated through a drying process after applying the adhesive. it is conceivable that. The oligomer deposited on the surface of the release layer is transferred to the surface of the adhesive layer to which the oligomer is attached, and a polarizing plate with the adhesive layer to which the oligomer is attached is attached to a glass substrate to produce an LCD. In some cases, problems such as a decrease in the brightness of the image may occur.
[0003]
In recent years, there has been a tendency to increase the brightness of the display screen for the purpose of improving the visibility of LCDs, and the above problem has become a serious problem. In addition, with the aim of reducing the manufacturing cost due to the improvement in productivity, with the increase in the speed of the manufacturing process, there is a tendency to set the drying temperature particularly higher in the drying process, and the above-mentioned oligomer is more likely to precipitate. It has become.
On the other hand, during the processing step, if the release film is charged by any action, if processing is continued using the release film, for example, when unwinding a roll-shaped release film, peeling charging occurs. In the pressure-sensitive adhesive application step, uneven application of the pressure-sensitive adhesive occurs. In a sheet-like laminate in which a release film and a polarizing plate are laminated via a pressure-sensitive adhesive layer, the sheet-like laminate is adhered when stacked. In addition, there may be a problem that the release film itself tends to attract foreign matter, dust and the like at the processing site.
[0004]
Therefore, even if countermeasures against static electricity are taken from the equipment side, such as installation of a static eliminator (eg, static elimination bar, ion blow, etc.), the level may not reach a level that does not cause any problems in processing. Prevention may be required.
In the inspection process that involves optical evaluation of the display performance, hue, contrast, and contamination of foreign materials such as liquid crystal polarizing plates, measures have been taken to prevent the outflow of defective products by visual observation or by using a magnifying glass. Since the optical anisotropy of the constituent polyester film may cause inconveniences such as foreign matter being easily overlooked, the release film must be peeled off at the time of inspection, and must be re-attached after the inspection. I have
[0005]
[Patent Document 1] JP-A-10-278203
[Patent Document 2] JP-A-2001-39038
[Patent Document 3] JP-A-2002-39960
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and the problem to be solved is to protect the pressure-sensitive adhesive layer used in the production of a liquid crystal component, the oligomer precipitation amount is as small as possible, antistatic properties, good transparency, optical An object of the present invention is to provide a release film that can be easily inspected with a target evaluation.
[0007]
[Means for Solving the Invention]
Means for Solving the Problems The present inventors have conducted intensive studies in view of the above situation, and as a result, have found that the use of a release film having a specific configuration can easily solve the above-described problems, and have completed the present invention.
That is, the gist of the present invention is a film used in manufacturing a liquid crystal component, a release film in which a coating layer containing a compound having a nitrogen element and a binder polymer and a release layer are sequentially provided on one surface of a polyester film. Wherein the following formulas (1) to (4) are satisfied at the same time.
OL ≦ 2.0 (1)
R ≦ 1 × 10^Thirteen  … (2)
TL ≧ 80 (3)
TL (H) ≦ 8 (4)
(In the above formula, OL is the amount of oligomer (mg / m 2) extracted from the surface of the release layer of the release film after heat treatment (180 ° C., 10 minutes) with dimethylformamide.²), R is the surface resistivity (Ω) of one of the release film surfaces, TL is the total light transmittance (%) of the release film, and TL (H) is the release film between the orthogonally polarizing plates. Represents the total light transmittance (%) of the laminate sandwiching
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
In the present invention, the polyester used for the polyester film may be a homopolyester or a copolyester.
In the case of a homopolyester, those obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like.
[0009]
On the other hand, in the case of a copolyester, it is preferably a copolymer containing 30 mol% or less of the third component. As the dicarboxylic acid component of the copolymerized polyester, one or two or more of isophthalic acid, terephthalic acid phthalate, 2,6-naphthalenedicarboxylic acid, sebacic acid adipate, oxycarboxylic acid (for example, P-oxybenzoic acid) and the like are used. And the glycol component includes one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, and the like.
[0010]
In any case, the polyester in the present invention means polyethylene terephthalate whose ethylene terephthalate unit is usually 80 mol% or more, preferably 90 mol% or more, and polyethylene-2,6-naphthalate which is an ethylene-2,6-naphthalate unit. And the like.
In the polyester layer of the present invention, particles are preferably blended for the purpose of mainly providing lubricity. The type of particles to be blended is not particularly limited as long as the particles can impart lubricity, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples include particles of magnesium silicon oxide, kaolin, aluminum oxide, titanium oxide and the like. Further, heat-resistant organic particles described in JP-B-59-5216 and JP-A-59-217755 may be used. Examples of other heat-resistant organic particles include a thermosetting urea resin, a thermosetting phenol resin, a thermosetting epoxy resin, a benzoguanamine resin, and the like. Further, during the polyester production process, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can be used.
[0011]
On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a massive shape, a rod shape, a flat shape and the like may be used. There is no particular limitation on the hardness, specific gravity, color and the like. These series of particles may be used in combination of two or more as necessary.
The average particle size of the particles used is usually in the range of 0.01 to 3 μm, preferably 0.01 to 1 μm. When the average particle size is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle size is more than 3 μm, the surface roughness of the film becomes too coarse, and Problems may occur when a release layer is applied in the process.
[0012]
Further, the content of particles in the polyester is usually in the range of 0.1 to 5% by weight, preferably 0.1 to 3% by weight. If the particle content is less than 0.1% by weight, the lubricity of the film may be insufficient, while if it exceeds 5% by weight, the transparency of the film may be insufficient. There are cases.
The method for adding particles to the polyester is not particularly limited, and a conventionally known method can be employed. For example, it can be added at any stage of producing the polyester, but preferably the polycondensation reaction may be advanced after the esterification stage or after the transesterification reaction is completed.
[0013]
Further, using a kneading extruder with a vent, a method of blending a slurry of particles dispersed in ethylene glycol or water and a polyester raw material, or a method of blending the dried particles and a polyester raw material using a kneading extruder. It is performed by a method or the like.
In addition, in addition to the above-mentioned particles, conventionally known antioxidants, heat stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film of the present invention, if necessary.
The thickness of the polyester film constituting the release film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 9 to 250 μm, preferably 9 to 188 μm, and more preferably 9 to 75 μm. Range.
[0014]
Next, the production examples of the polyester film in the present invention will be specifically described, but the invention is not limited to the following production examples.
That is, it is preferable to use the above-mentioned polyester raw material and cool and solidify a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet. In this case, it is preferable to increase the adhesion between the sheet and the rotary cooling drum in order to improve the flatness of the sheet, and the electrostatic application adhesion method and / or the liquid application adhesion method are preferably employed.
[0015]
Next, the obtained unstretched sheet is preferably stretched in at least one direction. The sheet may be biaxially stretched. In the case of biaxial stretching, the unstretched sheet is first stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually from 130 to 170 ° C., and the stretching ratio is usually from 2.5 to 7 times, preferably from 3.0 to 6 times. Next, stretching is performed in a direction orthogonal to the stretching direction of the first stage. The stretching temperature is usually 130 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, a heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film.
[0016]
A so-called coating / stretching method (in-line coating) for treating the film surface during the stretching step can be applied. Although it is not limited to the following, in particular, coating can be performed before the first-stage stretching is completed and before the second-stage stretching.
In the above stretching, a method of performing unidirectional stretching in two or more stages can also be used. In that case, it is preferable that the stretching is performed in such a manner that the stretching ratios in the two directions finally fall within the above ranges. It is also possible to simultaneously biaxially stretch the unstretched sheet so that the area magnification becomes 10 to 40 times. Further, if necessary, the film may be stretched in the longitudinal and / or transverse directions again before or after the heat treatment.
[0017]
When a coating layer is provided on a polyester film by the coating and stretching method described above, coating can be performed simultaneously with stretching, and the thickness of the coating layer can be reduced according to the stretching ratio, which is suitable as a polyester film. Film can be manufactured.
The release film in the present invention needs to simultaneously satisfy the following expressions (1) and (2).
OL ≦ 2.0 (1)
R ≦ 1 × 10^{1 3}  … (2)
(In the above formula, OL is the amount of oligomer (mg / m 2) extracted from the surface of the release layer of the release film after heat treatment (180 ° C., 10 minutes) with dimethylformamide.²), R is the surface resistivity (Ω) of one of the film surfaces of the release film)
[0018]
OL is 2.0mg / m²If the drying temperature is set higher, the amount of oligomers deposited on the surface of the release layer of the release film is increased when the drying temperature is set higher. Inconveniences such as a decrease in the adhesiveness and a decrease in the adhesive strength of the adhesive layer occur. For OL, 1.0 mg / m² _{Less than}Is preferred.
[0019]
On the other hand, R is 1 × 10^ThirteenIn the case of exceeding Ω, for example, when the roll-shaped release film is unwound, peeling and charging occur, and in the pressure-sensitive adhesive application step, problems such as uneven application of the pressure-sensitive adhesive occur. R is preferably 1 × 10¹²Ω or less, more preferably 1 × 10¹¹Ω or less, most preferably 1 × 10¹⁰Ω or less.
In the release film of the present invention, as a specific method for simultaneously satisfying the oligomer precipitation preventing property and the antistatic property, it is necessary that the coating layer constituting the release film contains a compound having a nitrogen element.
[0020]
Specific examples of the compound having a nitrogen element include, for example, a quaternary ammonium base-containing cation-based compound, and among them, if a polymer containing either an ionized nitrogen element or a pyrrolidium ring in its main chain is used. In particular, it has been found that not only the antistatic property is improved but also the oligomer has a remarkable anti-oligoprecipitation performance.
As an example of the polymer containing a nitrogen element ionized in the main chain, an ionene polymer is given as an example. Specific examples include JP-B-53-23377, JP-B-54-10039, JP-A-47-34581, JP-A-56-76451, JP-A-58-93710, and JP-A-58-93710. Examples described in JP-A-61-18750 and JP-A-63-68687 are exemplified.
[0021]
See ALAN D. WILSON and HAVARD J. PROSERSER (Ed.) DEVELOPMENTS IN IONIC POLYMERS-2ELSEVIER APPLIED SCIENCE PUBLISHER, 1986), IONENE POLYMERS :, PROPERTURES ANDAPPLICATIONS.
[0022]
In the present invention, the polymer having a pyrrolidium ring in the main chain is, for example, a polymer having a structure represented by the following formula (I) or (II) as a main component.
[0023]
Embedded image

[0024]
Embedded image

[0025]
In the above formulas (I) and (II), R¹, R²Are each independently an alkyl group, a phenyl group, or the like, and these alkyl groups and phenyl groups may be substituted with the following groups.
[0026]
Substitutable groups include, for example, a hydroxyl group, an amide group, a carbo lower alkoxy group, a lower alkoxy group, a thiophenoxy group, a cycloalkyl group, a tri- (lower alkyl) ammonium lower alkyl group, and a nitro group is an alkyl group. Only above, and the halogen group can be substituted only on the phenyl group. Also, R¹And R²May be chemically bonded, for example,-(CH₂)_m-(M = integer of 2 to 5), -CH (CH₃) -CH (CH₃)-, -CH = CH-CH = CH-, -CH = CH-CH = N-, -CH = CH-N = CH-,-(CH₂)₂O (CH₂)₂, (CH₂)₂O (CH₂)₂And the like. X in the above formula⁻Is Cl⁻, Br⁻, 1 / 2SO₄ ^2-Or 1 / 3PO₄ ^3-Such as an inorganic acid residue, CH₃SO₄ ⁻, C₂H₅SO₄ ⁻Represents a sulfonic acid residue.
[0027]
The polymer (I) in the present invention is obtained, for example, by subjecting a compound represented by the following formula (III) to cyclopolymerization using a radical polymerization catalyst.
[0028]
Embedded image

[0029]
The polymer of the formula (II) can be obtained by subjecting the compound of the formula (III) to cyclopolymerization in a system using sulfur dioxide as a solvent. Polymerization is carried out using a known polymerization initiator such as hydrogen peroxide, benzoyl peroxide, or tertiary butyl peroxide in a solvent such as water or a polar solvent such as methanol, ethanol, isopropanol, formamide, dioxane, acetonitrile, or sulfur dioxide. The method can be implemented, but is not limited to these.
[0030]
In the present invention, the polymer having a pyrrolidium ring in the main chain may be a compound having a polymerizable carbon-carbon unsaturated bond with the compound of the above formula (III) as a copolymerization component.
The molecular weight of the polymer having a pyrrolidium ring in the main chain in the present invention is preferably 500 to 1,000,000, and more preferably 1,000 to 500,000. When the molecular weight of the polymer is less than 500, although the polymer has an antistatic effect, the strength of the coating film tends to be weak or the film tends to be easily blocked. When the molecular weight of the polymer is higher than 1,000,000, the viscosity of the coating solution becomes high, and the handling property and the coating property tend to deteriorate.
[0031]
The content of the compound having a nitrogen element contained in the coating layer is not particularly limited, but is preferably from 10 to 99% by weight, and more preferably from 20 to 95% by weight.
Further, in the coating layer constituting the release film in the present invention, it is necessary to contain a binder polymer in consideration of coating film durability, film forming property and the like of the coating layer.
Specific examples of the binder polymer contained in the coating layer include polyvinyl alcohol (hereinafter sometimes abbreviated as PVA), polyacrylamide, polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starch, polyurethane, and polyester. , Polyacrylates, chlorine-based polymers (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, etc.), polyolefins and the like. Among them, when the coating layer is formed by a coating and stretching method, nonionic, cationic, and amphoteric organic polymers that can be used as an aqueous solution or aqueous dispersion can be used. For this reason, it is preferable that polyvinyl alcohol is contained as a suitable combination with the above-mentioned compound having a nitrogen element.
[0032]
The content of the binder polymer such as polyvinyl alcohol contained in the coating layer is not particularly limited, but is preferably in the range of 10 to 90% by weight, more preferably 10 to 80% by weight. If the content of the binder polymer is less than 10% by weight, problems such as insufficient film-forming properties of the coating layer may occur.
The degree of polymerization of the PVA used in the present invention is not particularly limited, but usually 100 or more, preferably 300 to 40,000 is suitably used for applications.
On the other hand, the degree of saponification of PVA is not particularly limited, but one having 70 mol% or more, preferably 80 mol% or more and 99.9 mol% or less is suitably used. And the like.
[0033]
Further, a crosslinking agent may be used in combination in the coating layer. Specific examples thereof include methylolated or alkylolated urea-based, melamine-based, guanamine-based, acrylamide-based, polyamide-based compounds, epoxy compounds, aziridine compounds, and blocked polyisocyanates. , A silane coupling agent, a titanium coupling agent, a zirco-aluminate coupling agent, and the like. These crosslinking components may be pre-bonded to the binder polymer.
Further, inorganic particles may be contained for the purpose of improving the fixability and slipperiness of the coating layer, and specific examples thereof include silica, alumina, kaolin, calcium carbonate, titanium oxide, and barium salt. Further, if necessary, an antifoaming agent, a coating improver, a thickener, an organic lubricant, an organic polymer particle, an antioxidant, an ultraviolet absorbent foaming agent, a dye and the like may be contained.
[0034]
The coating amount (after drying) of the coating layer constituting the release film in the present invention is usually 0.01 to 1 g / m.², Preferably 0.03 to 0.5 g / m²Range is good. Coating amount is 0.01 g / m²If less than 1 g / m, the uniformity of the applied thickness may be insufficient.²When the coating is performed in excess of the above range, problems such as reduced slipperiness may occur.
In the present invention, the method of providing the coating layer constituting the release film may be a conventionally known coating method such as reverse gravure coating, gravure coating, bar coating, and die coating, as in the case of providing a releasing layer described below. it can.
[0035]
The coating layer is preferably provided on the polyester film by the above-mentioned coating and stretching method (in-line coating method).
It is preferable to include a curable silicone resin in the release layer constituting the release film of the present invention since the release property is improved. A type containing a curable silicone resin as a main component or a modified silicone type obtained by graft polymerization with an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin may be used.
As the type of the curable silicone resin, any of a curing reaction type such as an addition type, a condensation type, an ultraviolet curable type, an electron beam curable type, and a solventless type can be used.
Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422, X-62-2461, Dow made by Shin-Etsu Chemical Co., Ltd. -DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210 manufactured by Corning Asia Co., Ltd., YSR-3022, TPR-6700, TPR-6720, TPR-6721, manufactured by Toshiba Silicone Co., Ltd. Toray Dow Corning Co., Ltd. SD7220, SD7226, SD7229, LTC750A etc. are mentioned. Further, a release control agent may be used in combination to adjust the release property of the release layer.
[0036]
As a method of providing a release layer on the coating layer constituting the release film of the present invention, a conventionally known coating method such as reverse gravure coat, gravure coat, bar coat, die coat, curtain coat and the like can be used.
The coating amount of the release layer is usually 0.01 to 1 g / m from the viewpoint of coatability.², Preferably 0.03 to 0.5 g / m²Range. Coating amount is 0.01 g / m²If the amount is less than the above range, stability may be lacked from the viewpoint of coatability, and it may be difficult to obtain a uniform coating film. On the other hand, 1 g / m²If the thickness is too large, the adhesiveness of the release layer itself, the curability and the like may be reduced.
[0037]
With respect to the release film of the present invention, a coating layer such as an adhesive layer, an antistatic layer, and an oligomer precipitation preventing layer may be provided on a surface on which the release layer is not provided. May be applied.
It is necessary for use that the total light transmittance (TL) of the release film of the present invention is 80% or more. If the TL is less than 80%, the transparency becomes insufficient, and in the inspection process involving optical evaluation, problems such as the intrusion of foreign matter easily being overlooked occur.
Further, the total light transmittance (TL (H)) when the release film of the present invention is laminated between orthogonally polarizing plates must be 8% or less, preferably 5% or less, and more preferably 5% or less. Preferably it is 2% or less. When TL (H) is more than 8%, in the inspection step of the liquid crystal polarizing plate, defects such as uneven polarization are caused due to the optical anisotropy of the polyester film constituting the release film.
[0038]
In addition, the release film of the present invention is used for the purpose of using the angle (θ₃) Preferably satisfies 70 ° or more. θ₃Is preferably 80 degrees or more. θ₃If the angle is less than 70 degrees, it is easy to overlook the contamination of foreign substances in the inspection process involving optical evaluation, and there may be a problem that the release film must be peeled off at the time of the inspection and must be attached again after the inspection. is there.
The residual adhesive ratio of the release layer constituting the release film of the present invention is preferably 90% or more, and more preferably 90% or more, in order to suppress the transfer or transfer of silicone to the pressure-sensitive adhesive layer to be bonded. Is preferably 95% or more. When the residual adhesive ratio is less than 90%, in the manufacturing process, problems such as the transfer of the silicone transfer component to the roll surface of the transport roll and the decrease in the adhesive force of the adhesive layer in contact with the release surface may occur. There are cases.
[0039]
【Example】
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. The measuring method used in the present invention is as follows.
[0040]
(1) Measurement of intrinsic viscosity of polyester
1 g of the polyester, from which other polymer components and pigments incompatible with the polyester were removed, was precisely weighed, dissolved in 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio), and measured at 30 ° C.
[0041]
(2) Average particle size (d₅₀: Μm)
The value of 50% integrated (weight basis) in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 manufactured by Shimadzu Corporation) was defined as the average particle size.
[0042]
(3) Measurement of the amount of oligomer (OL) extracted from the surface of the release layer of the release film
Top open, bottom area 250cm²The release film after the heat treatment (180 ° C., 10 minutes) is folded so as to obtain a square box. When a coating layer is provided, the coating layer surface is on the inside.
Next, 10 ml of DMF is put in the box created by the above method and left for 3 minutes, and then DMF is collected. The recovered DMF was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of oligomer in DMF, and this value was divided by the area of the film contacted with DMF to obtain the amount of oligomer on the film surface (mg / mg). m²).
The amount of oligomer in DMF was determined from the peak area ratio between the standard sample peak area and the measurement sample peak area (absolute calibration curve method).
A standard sample was prepared by accurately weighing oligomers (cyclic trimers) that had been collected in advance and dissolving them in DMF that had been accurately weighed. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml.
[0043]
The conditions of the liquid chromatography were as follows.
Mobile phase A: acetonitrile
Mobile phase B: 2% acetic acid aqueous solution
Column: “MCI GEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min
Detection wavelength: 254 nm
[0044]
(4) Measurement of total light transmittance (TL) of release film
The total light transmittance (%) of the release film was measured using an integrating sphere turbidity meter “NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K-7105.
[0045]
(5) In the release film, the angle (θ) of the main orientation axis in the film plane with respect to the MD direction₃) Measurement
Using a Carl Zeiss polarizing microscope, observe the orientation of the release film, and evenly determine in the film width direction how many directions of the main orientation axis in the polyester film plane are inclined with respect to the MD direction of the polyester film. 10 points were measured, and the maximum value of those measured values was θ₃And
In the measurement, when the main orientation axis exceeds 90 degrees, the supplementary angle is defined as the angle of the main orientation axis with respect to the MD direction.
[0046]
(6) Measurement of total light transmittance (TL (H)) when a release film is sandwiched between orthogonal polarizing plates
Release film between polarizing plates (Nitto Denko: 99.99% polarization ratio) crossed by an integrating sphere turbidimeter "NDH-300A" manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K-7105. , The total light transmittance (%) in the state of the laminate was measured.
As the TL (H) value is smaller, polarization unevenness and the like are less likely to occur, and the inspection of the polarizing plate can be easily performed.
[0047]
(7) Evaluation of residual adhesion rate of release film
(1) Residual adhesive strength
On the silicone surface of the sample film, Nitto Denko (manufactured) No. The 31B pressure-sensitive adhesive tape is pressed back and forth with a 2 kg rubber roller once, and heat-treated at 100 ° C. for 1 hour. Next, the sample film was peeled off from the crimped sample. The adhesive strength of the 31B adhesive tape is measured according to the method of JIS-C-2107 (adhesive strength to stainless steel plate, 180 ° peeling method). This is defined as the residual adhesive strength.
[0048]
(2) Basic adhesive strength
Using the same tape (No. 31B) as in the case of the residual adhesive force, an adhesive tape is pressure-bonded to a stainless steel plate according to JIS-C-2107, and the measurement is performed in the same manner. The value at this time is defined as the basic adhesive strength. Using these measured values, the residual adhesion ratio is determined based on the following equation.
Residual adhesion rate (%) = (Residual adhesive strength) × 100 / (Basic adhesive strength)
The measurement is performed at 20 ± 2 ° C. and 65 ± 5% RH.
[0049]
(8) Evaluation of release force (F) of release film
After affixing one side of a double-sided adhesive tape (“No. 502” manufactured by Nitto Denko) to the release layer of the measurement sample, cut it into a size of 50 mm × 300 mm, and measure the peeling force after leaving at room temperature for 1 hour. I do. The peeling force was 180 ° peeled using a tensile tester (“Intesco Model 2001” manufactured by Intesco Corporation) under the condition of a tensile speed of 300 mm / min.
[0050]
(9) Evaluation of antistatic property (R) of release film
A measurement electrode was installed on a measurement electrode of HP16008B (trade name) manufactured by Hewlett-Packard Japan under a 50% RH atmosphere at 23 ° C., a voltage of 100 V was applied, and a high resistance meter HP4339B (trade name) of the company was used. The surface resistivity was measured.
[0051]
(10) Evaluation of extinction state of release film
In the laminate in which the release film and the polarizing plate were bonded via the pressure-sensitive adhesive layer to which the foreign matter was attached, the presence or absence of an extinction state when viewed through light from the release film side was observed.
[0052]
(11) Evaluation of testability of release film
In the laminate in which the release film and the polarizing plate were bonded via the pressure-sensitive adhesive layer to which the foreign matter was adhered, the visibility of the foreign matter when viewed through light from the side of the release film was evaluated according to the following criteria.
《Criteria》
Good: Inspection possible (no problem in practical use)
Slightly defective: In some cases, inspection is difficult (level that is problematic for practical use)
Defective: Inspection impossible (level with practical problems)
[0053]
<Manufacture of polyester>
Production Example 1 (Polyethylene terephthalate A1)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate were placed in a reactor, heated and heated, and methanol was distilled off to carry out a transesterification reaction. It took 4 hours from the start of the reaction. And the temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of ethylene glycol slurry ethyl acid phosphate, 0.03 part of antimony trioxide, and 0.3 part of silica particles having an average particle size of 0.25 μm were added. The pressure reached 15 mmHg, and thereafter the pressure was gradually reduced to finally 0.3 mmHg. After 4 hours, the inside of the system was returned to normal pressure to obtain polyethylene terephthalate A1 having an intrinsic viscosity of 0.61.
[0054]
Production Example 2 (Polyethylene terephthalate A2)
Polyethylene terephthalate A2 was prepared in the same manner as in Production Example 1 except that 1 part of titanium oxide particles having an average particle size of 0.27 μm was added instead of adding 0.3 parts of silica particles having an average particle size of 0.25 μm. Got.
[0055]
<Manufacture of polyester film>
Production Example 3 (Polyester film F1)
The polyethylene terephthalate A1 produced in Production Example 1 was dried at 180 ° C. for 4 hours in an inert gas atmosphere, melted at 290 ° C. by a melt extruder, extruded from a die, and brought to a surface temperature of 40 using an electrostatic application adhesion method. The mixture was cooled and solidified on a cooling roll set at a temperature of ° C. to obtain an unstretched sheet. The obtained sheet was stretched 3.5 times in the longitudinal direction at 85 ° C.
Next, after applying a coating agent having the following composition, the film was guided to a tenter, stretched 3.7 times in the transverse direction at 100 ° C., and then heat-fixed at 230 ° C., and only the central portion having a width of 1,000 mm was collected. Work volume is 0.05g / m²A PET film F1 having a thickness of 25 μm and provided with a coating layer (after drying) was obtained.
[0056]
《Example of compound》
{Circle around (1)} Compound having nitrogen element (A): compound having pyrrolidium ring in main chain
(Daiichi Kogyo Seiyaku Co., Ltd .: Sharoll DC-303P)
(2) Compound containing nitrogen element (B): quaternary polytrimethylaminoethyl methacrylate
{Circle around (3)} Acrylic resin (C): copolymer of alkyl acrylate and alkyl methacrylate (Tg: about 40 ° C.) (Nippon Carbide Industrial: Nicazole)
{Circle around (4)} PVA-based resin (D): polyvinyl alcohol having a degree of saponification of 88 mol% and a degree of polymerization of 500
{Circle around (5)} Crosslinkable compound (E): methoxymethylol melamine (manufactured by Dainippon Ink and Chemicals, Inc .: becamine)
{Circle around (6)} Crosslinkable compound (F): zirconium compound (Zircosol ZC-2 manufactured by Daiichi Kagaku Kagaku Kogyo Co., Ltd.)
{Circle around (7)} Particles (G): silica sol having an average particle diameter of 0.05 μm
[0057]
《Coating composition》
Compound having nitrogen element (A): 85% by weight, PVA-based resin (D): 10% by weight, particles (G): 5% by weight
[0058]
Production Example 4 (PET film F2) to Production example 8 (PET film F6)
In Production Example 2, PET films F2 to F6 were obtained in the same manner as in Production Example 2, except that the coating composition was changed to the coating composition shown in Table 1 below. The properties of this film are shown in Table 1 below.
[0059]
Production Example 9 (PET film F7)
In Production Example 3, a PET film F7 was obtained in the same manner as in Production Example 3, except that polyethylene terephthalate A2 was used instead of polyethylene terephthalate A1. The properties of this film are shown in Table 1 below.
[0060]
Production Example 10 (PET film F8)
In Production Example 3, a PET film F8 was obtained in the same manner as in Production Example 3, except that the width of the end portion was 1000 mm and the sampling position was different. The properties of this film are shown in Table 1 below.
[0061]
Production Example 11 (PET film F9)
The PET film F9 was obtained in the same manner as in Production Example 3 except that a 1000 mm width was collected at a portion between the central portion of 1,000 mm width collected in Production Example 3 and the end portion of 1,000 mm width collected in Production Example 9. Was. The properties of this film are shown in Table 1 below.
[0062]
[Table 1]

[0063]
Example 1
The coating amount (after drying) of the release layer having the following release agent composition was 0.1 g / m 2 on the PET film F1 obtained in Production Example 3.²To obtain a release film. The properties of this release film are shown in Table 2 below.
<< Release agent composition >>
Curable silicone resin: (KS-847H: Shin-Etsu Chemical solid content concentration 30%) 99% by weight
Curing agent: (PL-50T: Shin-Etsu Chemical's solid content concentration 1%) 1% by weight
The release agent was diluted with a mixed solvent of MEK / toluene (mixing ratio was 1: 1) to prepare a coating solution having a concentration of 1.5% by weight.
[0064]
Example 2
A release film was obtained in the same manner as in Example 1, except that the composition of the release agent was changed to the following composition. Table 2 shows the characteristics of the release film.
<< Release agent composition >>
Curable silicone resin: (KS-774: solid content concentration 30%, manufactured by Shin-Etsu Chemical) 99% by weight
Curing agent: (PL-3: solid content concentration 30%, manufactured by Shin-Etsu Chemical) 1% by weight
The release agent was diluted with a mixed solvent of MEK / toluene (mixing ratio was 1: 1) to prepare a coating solution having a concentration of 1.5% by weight.
[0065]
Example 3
A release film was obtained in the same manner as in Example 1 except that the PET film F2 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0066]
Example 4
A release film was obtained in the same manner as in Example 1 except that the PET film F3 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0067]
Example 5
A release film was obtained in the same manner as in Example 1 except that the PET film F4 was used instead of the PET film F1. Table 2 shows the properties of the release film.
[0068]
Example 6
A release film was obtained in the same manner as in Example 1 except that the PET film F9 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0069]
Comparative Example 1
A release film was obtained in the same manner as in Example 1 except that the PET film F5 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0070]
Comparative Example 2
A release film was obtained in the same manner as in Example 1 except that the PET film F6 was used instead of the PET film F1. Table 2 shows the properties of the release film.
[0071]
Comparative Example 3
A release film was obtained in the same manner as in Example 1, except that the composition of the release agent was changed to the following composition. Table 2 shows the characteristics of the release film.
<< Release agent composition >>
Curable silicone resin: (KS-847H: Shin-Etsu Chemical solid content concentration 30%) 98% by weight
Curing agent: (PL-50T: Shin-Etsu Chemical's solid content concentration 1%) 1% by weight
Non-reactive silicone oil: (X-22-819: specific gravity 0.99 (25 ° C.) manufactured by Shin-Etsu Chemical) 1% by weight
The release agent was diluted with a mixed solvent of MEK / toluene (mixing ratio was 1: 1) to prepare a coating solution having a concentration of 1.5% by weight.
[0072]
Comparative Example 4
A release film was obtained in the same manner as in Example 1 except that the PET film F7 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0073]
Comparative Example 5
A release film was obtained in the same manner as in Example 1 except that the PET film F8 was used instead of the PET film F1. Table 2 shows the characteristics of the release film.
[0074]
[Table 2]

[0075]
[Table 3]

[0076]
【The invention's effect】
The release film of the present invention has a minimum amount of oligomer precipitation, good antistatic properties, good transparency, and good optical evaluation for protecting an adhesive layer used in the production of liquid crystal components such as a liquid crystal polarizing plate and a retardation plate. It is a release film that can be easily inspected, and its industrial value is extremely high.

Claims (6)

A film used in manufacturing a liquid crystal component, which is a release film in which a coating layer containing a compound having a nitrogen element and a binder polymer and a release layer are sequentially provided on one surface of a polyester film, and the following formula (1) A release film for protecting an adhesive layer, which simultaneously satisfies (4) to (4).
OL ≦ 2.0 (1)
R ≦ 1 × 10 ¹³ (2)
TL ≧ 80 (3)
TL (H) ≦ 8 (4)
(In the above formula, OL is the amount of oligomers (mg / m ² ) extracted from the surface of the release layer of the release film after heat treatment (180 ° C., 10 minutes) with dimethylformamide, and R is any one of the release films. , TL is the total light transmittance (%) of the release film, and TL (H) is the total light transmittance of the laminate in which the release film is interposed between orthogonally polarizing plates ( %) 2. The release film according to claim 1, wherein the angle (θ ₃ ) of the main orientation axis in the film plane with respect to the MD direction in the release film is 70 degrees or more. The release film according to claim 1, wherein the compound having a nitrogen element is a compound having a quaternary ammonium base. The release film according to any one of claims 1 to 3, wherein the binder polymer is polyvinyl alcohol. The release film according to any one of claims 1 to 4, wherein the coating layer is provided on the polyester film by a coating stretching method (in-line coating method). The release film according to any one of claims 1 to 5, wherein the release layer contains a curable silicone resin.