JP3863253B2 - Liquid crystal display element and manufacturing method thereof - Google Patents

Description

【００４６】
（上記式中、Ｒは水素、低級アルキル、低級アルコキシまたはハロゲンを示し、ｍは１〜３の整数を示し、ｍが２又は３の時、Ｒは異なった種類であっても良い。ｎは０又は正の整数である。）で表されるものである。
【００４７】
上記式において、低級アルキルとしては、例えばメチル、エチル、ｎ−プロピル、イソプロピル、ｎ−ブチル、イソブチル、ｔ−ブチル等のＣ１〜Ｃ４のアルキルが、低級アルコキシとしては、例えばメトキシ、エトキシ、ｎ−プロポキシ、イソプロポキシ、ｎ−ブトキシ、イソブトキシ、ｔ−ブトキシ等のＣ１〜Ｃ４のアルコキシが、ハロゲンとしては、例えば臭素等が挙げられる。ｎにおける正の整数は１〜１０が好ましい。
【００４８】
本発明で使用するフェノール系ノボラック樹脂からなる硬化剤は、上記式の化合物において，ｎ＝１以上である成分は軟化点が高いので、ｎ＝０である成分が存在している方が好ましく、その存在量は、ノボラック樹脂中通常２０〜８０重量％、好ましくは２５〜７０重量％、より好ましくは３０〜５０重量％程度である（残りはｎ＝１以上である成分）。
【００４９】
上記フェノール系ノボラック樹脂と液状エポキシ樹脂との混合物は、常温で液状であるか又は環球法の測定で50℃以下の軟化点を有するものであることが好ましい。
【００５０】
また、本発明で使用するフェノール系ノボラック樹脂からなる硬化剤は、好ましくはエポキシ等量が２３０以下の液状エポキシ樹脂との組み合わせにおいて，ガラス基板との接着性と耐湿信頼性が優れている。
【００５１】
フェノール系ノボラック樹脂のエポキシ樹脂との反応において、２核体（例えば、上記式においてｎ＝０の化合物）のフェノールノボラック樹脂は、３核体以上（例えば、上記式においてｎ＝１の化合物）のフェノールノボラック硬化剤の硬化による３次元架橋構造に対して線形に架橋するために剛直な構造に可撓性がでるため、ガラス基板との接着性が向上している。
【００５２】
更に、本発明で用いられるフェノールノボラック樹脂は軟化点が７５°Ｃ以下と低いために、液晶素子製造時の上下ガラス基板貼り合わせプロセス時の液晶シール剤の樹脂粘度が低いものとなり、貼り合わせ、ギャップ形成が容易になる。本発明で使用する前記充填剤（ｃ）としては、溶融シリカ、結晶シリカ、シリコンカーバイド、窒化珪素、窒化ホウ素、炭酸カルシウム、炭酸マグネシウム、硫酸バリウム、硫酸カルシウム、マイカ、タルク、クレー、アルミナ、酸化マグネシウム、酸化ジルコニウム、水酸化アルミニウム、水酸化マグネシウム、珪酸カルシウム、珪酸アルミニウム、珪酸リチウムアルミニウム、珪酸ジルコニウム、チタン酸バリウム、硝子繊維、炭素繊維、二硫化モリブデン、アスベスト等が挙げられ、好ましくは、溶融シリカ、結晶シリカ、窒化珪素、窒化ホウ素、炭酸カルシウム、硫酸バリウム、硫酸カルシウム、マイカ、タルク、クレー、アルミナ、水酸化アルミニウム、珪酸カルシウム、珪酸アルミニウムであり、更に好ましくは溶融シリカ、結晶シリカ、アルミナである。
【００５３】
これらの充填剤は２種以上を混合して用いても良く、特に好ましくはシリカとアルミナを併用した場合である。
【００５４】
本発明で用いられる充填剤の最大粒径は、レーザー法の測定で１０μｍ以下、好ましくは６μｍ以下、更に好ましくは４μｍ以下であり、特に好ましくは４μｍ以下でその平均粒径が２μｍ以下であるものである。
【００５５】
１０μｍより充填剤の粒径が大きいと、液晶表示素子製造時の上下基板の貼り合わせ後のギャップ形成がうまくできない。このような充填剤のシリカは、例えば溶融シリカ又は結晶シリカを粉砕し、分級することによって製造される。
【００５６】
アルミナは、例えば水酸化アルミニウムを焼成してできたアルミナ又は無水塩化アルミニウムの火焔加水分解によってできたアルミナ又はアンモニウム明ばんを焼成して得られたアルミナを粉砕、分級して製造される。
【００５７】
本発明で使用される充填剤の液晶シール剤中の含有量は、溶剤を除いた液晶シール剤中５〜３０体積％、より好ましくは１５〜２５体積％である。
【００５８】
充填剤の含有量が５体積％より低い場合、充填剤量が少ないため低粘度になり、液晶シール剤塗布後にガラス基板上でだれ、はじきが起こりやすくなり、シール形状が乱れてしまう恐れがある。また、充填剤の含有量が３０体積％より多い場合、充填剤含有量が多すぎるため潰れ難く、液晶表示素子のギャップ形成ができなくなってしまう。
【００５９】
本発明に用いられる前記硬化促進剤（ｄ）としては、例えばイミダゾール類、イミダゾール類とフタル酸、イソフタル酸、テレフタル酸、トリメリット酸、ピロメリット酸、ナフタレンジカルボン酸、マレイン酸、蓚酸等の多価カルボン酸との塩類、ジシアンジアミド等のアミド類及び該アミド類とフェノール類、前記多価カルボン酸類、又はフォスフィン酸類との塩類、１，８−ジアザ−ビシクロ（５．４．０）ウンデセン−７等のジアザ化合物及び該ジアザ化合物とフェノール類、前記多価カルボン酸類、又はフォスフィン酸類、トリフェニルホスフィン、テトラフェニルホスホニウムテトラフェニルボレート等のホスフィン類、２，４，６−トリスアミノメチルフェノール等のフェノール類、アミンアダクト等が挙げられる。
【００６０】
イミダゾール類としては２−メチルイミダゾール、２−フェニルイミダゾール、２−ウンデシルイミダゾール、２−ヘプタデシルイミダゾール、２−フェニル−４−メチルイミダゾール、１−ベンジル−２−フェニルイミダゾール、１−ベンジル−２−メチルイミダゾール、１−シアノエチル−２−メチルイミダゾール、１−シアノエチル−２−フェニルイミダゾール、１−シアノエチル−２−ウンデシルイミダゾール、２，４−ジアミノー６（２’−メチルイミダゾール（１’））エチル−ｓ−トリアジン、２，４−ジアミノ−６（２’−ウンデシルイミダゾール（１’））エチル−ｓ−トリアジン、２，４−ジアミノ−６（２’−エチル、４−メチルイミダゾール（１’））エチル−ｓ−トリアジン、２，４−ジアミノ−６（２’−メチルイミダゾール（１’））エチル−ｓ−トリアジン・イソシアヌル酸付加物、２−メチルイミダゾールイソシアヌル酸の２：３付加物、２−フェニルイミダゾールイソシアヌル酸付加物、２−フェニル−３、５−ジヒドロキシメチルイミダゾール、２−フェニル−４−ヒドロキシメチル−５−メチルイミダゾール、１−シアノエチル−２−フェニル−３、５−ジシアノエトキシメチルイミダゾール等が挙げられる。
【００６１】
これら硬化促進剤のうち好ましいものとしては、例えば、２，４−ジアミノ−６（２’−メチルイミダゾール（１’））エチル−ｓ−トリアジン・イソシアヌル酸付加物、２−メチルイミダゾールイソシアヌル酸の２：３付加物、２−フェニルイミダゾールイソシアヌル酸付加物、イミダゾール類とフタル酸、イソフタル酸、テレフタル酸、トリメリット酸、ピロメリット酸、ナフタレンジカルボン酸、マレイン酸、蓚酸等の多価カルボン酸との塩類、アミンアダクト等が挙げられる。
【００６２】
硬化促進剤の添加量は、エポキシ樹脂１００重量部に対して０．５〜２０重量部好ましくは１〜１０重量部である。
【００６３】
これら硬化促進剤は、潜在性硬化促進剤の形式で使用した方が作業性の向上（ポットライフ時間の延長）等のメリットがあり、好ましい。
【００６４】
潜在性硬化促進剤は室温では固体で、加熱されることによって溶解し、初めて硬化促進剤として反応するという性質を有するもので、例えばこれら硬化促進剤をマイクロカプセルにしたマイクロカプセル型硬化促進剤や溶剤やエポキシ樹脂に溶解しにくい固体分散型の硬化促進剤（例えばイミダゾール類）、アミンアダクト等が挙げられる。
【００６５】
これら硬化促進剤のうち、固体分散型の潜在性硬化促進剤の平均粒径はレーザー法の測定で６μｍ以下、好ましくは４μｍ以下、より好ましくは３μｍ以下程度である。平均粒径が６μｍより大きい潜在性硬化促進剤を使用すると、ディスペンサ塗布が難しく、また、塗布後の形状も均一でなく、そのため、シール後のシール形状も均一でなくなってしまう。
【００６６】
また、平均粒径が６μｍより大きい硬化促進剤を使用した液晶シール剤のシール後のシール部に充填剤の荒い粗密が確認される。
【００６７】
本発明の液晶シール剤は、上記の液状エポキシ樹脂（ａ）、環球法による軟化点７５°Ｃ以下のノボラック樹脂からなる硬化剤（ｂ）、粒径が１０μｍ以下の充填剤（ｃ）、及び硬化促進剤（ｄ）を必須成分とし、（ａ）成分と（ｂ）成分の（溶融）混合物の軟化点が環球法の測定で５０°Ｃ以下、好ましくは４０°Ｃ以下、より好ましくは３０°Ｃ以下、更に好ましくは常温で液状であることを特徴とする。軟化点が５０°Ｃより高い場合には、溶剤を使用して液状の液晶シール剤とするが、この場合溶剤揮発後のシール剤が固形となり、液晶素子製造時の上下ガラス基板の貼り合わせは、上下ガラス基板への加熱なしで行うために、上下ガラス基板を貼り合わせるときに常温では液晶シール剤がつぶれないので、液晶セルの製造ができない。
【００６８】
本発明の液晶シール剤が常温で液状である場合、その粘度は作業性を考慮すると２００〜４００ポイズ（２５°Ｃ）程度が適当である。更に，そのチクソ性としては０．８〜１．１程度が適当である。
【００６９】
本発明の液晶シール剤には、１種又は２種以上の固形エポキシ樹脂を加えることができる。用いられる固形エポキシ樹脂としては、ビスフェノールＡ、ビスフェノールＦ、ビスフェノールＳ、４，４’−ビフェニルフェノール、２，２’，６，６’−テトラメチル−４，４’−ビフェニルフェノール、２，２’−メチレン−ビス（４−メチル−６−ｔｅｒｔ−ブチルフェノール），トリスヒドロキシフェニルメタン、ピロガロール、ジイソプロピリデン骨格を有するフェノール類、１，１−ジ−４−ヒドロキシフェニルフルオレン等のフルオレン骨格を有するフェノール類、フェノール化ポリブタジエン等のポリフェノール化合物のグリシジルエーテル化物である多官能エポキシ樹脂、フェノール、クレゾール類、エチルフェノール類、ブチルフェノール類、オクチルフェノール類、ビスフェノールＡ、テトラブロムビスフェノールＡ、ビスフェノールＦ、ビスフェノールＳ、ナフトール類等の各種フェノールを原料とするノボラック樹脂、キシリレン骨格含有フェノールノボラック樹脂、ジシクロペンタジエン骨格含有フェノールノボラック樹脂、フルオレン骨格含有フェノールノボラック樹脂等の各種ノボラック樹脂のグリシジルエーテル化物、シクロヘキサン等の脂肪族骨格を有する脂環式エポキシ樹脂、イソシアヌル環、ヒダントイン環等の複素環を有する複素環式エポキシ樹脂、ブロム化ビスフェノールＡ、ブロム化ビスフェノールＦ、ブロム化ビスフェノールＳ、ブロム化フェノールノボラック、ブロム化クレゾールノボラック等のブロム化フェノール類をグリシジル化したエポキシ樹脂が挙げられ、その使用量は得られたシール剤の融点、作業性、物性に影響を与えない範囲で用いられる。
【００７０】
また、この固形エポキシ樹脂の全塩素量は１５００ｐｐｍ以下、好ましくは１２００以下、更に好ましくは１０００以下である。全塩素量が１５００以上では液晶セルのＩＴＯ電極の腐食が著しくなる。
【００７１】
本発明の液晶シール剤には、カップリング剤を加えることができる。カップリング剤としては、例えば３−グリシドキシプロピルトリメトキシシラン、３−グリシドキシプロピルメチルジメトキシシラン、３−グリシドキシプロピルメチルジメトキシシラン、２−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、Ｎ−フェニル−γ−アミノプロピルトリメトキシシラン、Ｎ−（２−アミノエチル）３−アミノプロピルメチルジメトキシシラン、Ｎ−（２−アミノエチル）３−アミノプロピルメチルトリメトキシシラン、３−アミノプロピルトリエトキシシラン、３−メルカプトプロピルトリメトキシシラン、ビニルトリメトキシシラン、Ｎ−（２−（ビニルベンジルアミノ）エチル）３−アミノプロピルトリメトキシシラン塩酸塩、３−メタクリロキシプロピルトリメトキシシラン、３−クロロプロピルメチルジメトキシシラン、３−クロロプロピルトリメトキシシラン等のシラン系カップリング剤、イソプロピル（Ｎ−エチルアミノエチルアミノ）チタネート、イソプロピルトリイソステアロイルチタネート、チタニュウム（ジオクチルピロフォスフェート）オキシアセテート、テトライソプロピルジ（ジオクチルフォスファイト）チタネート、ネオアルコキシトリ（ｐ−Ｎ−（β−アミノエチル）アミノフェニル）チタネート等のチタン系カップリング剤、Ｚｒ−アセチルアセトネート、Ｚｒ−メタクリレート、Ｚｒ−プロピオネート、ネオアルコキシジルコネート、ネオアルコキシトリスネオデカノイルジルコネート、ネオアルコキシトリス（ドデカノイル）ベンゼンスルフォニルジルコネート、ネオアルコキシトリス（エチレンジアミノエチル）ジルコネート、ネオアルコキシトリス（ｍ−アミノフェニル）ジルコネート、アンモニウムジルコニウムカーボネート、Ａ１−アセチルアセトネート、Ａ１−メタクリレート、Ａ１−プロピオネート等のジルコニウム、あるいはアルミニウム系カップリング剤が挙げられるが、好ましくはシリコン系カップリング剤であり、更に好ましくはアミノシラン系カップリング剤である。
【００７２】
カップリング剤を使用することにより耐湿信頼性が優れ、吸湿後の接着強度の低下が少ない液晶シール剤が得られる。
【００７３】
本発明の液晶シール剤は、粘度を低くして作業性を向上させるために溶剤を添加しても良い。使用し得る溶剤としては、例えばアルコール系溶剤、エーテル系溶剤、アセテート系溶剤が挙げられ、これらは１種又は２種以上を単独で又は混合して、任意の比率で用いることができる。
【００７４】
アルコール系溶剤としては、例えばエタノール、イソプロピルアルコール等のアルキルアルコール類、３−メチル−３−メトキシブタノール、３−メチル−３−エトキシブタノール、３−メチル−３−ｎ−プロポキシブタノール、３−メチル−３−ｎ−ブトキシブタノール、３−メチル−３−イソブトキシブタノール、３−メチル−３−ｓｅｃ−ブトキシブタノール、３−メチル−３−ｔｅｒｔ−ブトキシブタノール等のアルコキシアルコール類が挙げられる。
【００７５】
エーテル系溶剤としては、例えば１価アルコールエーテル系溶剤、アルキレングリコールモノアルキルエーテル系溶剤、アルキレングリコールジアルキルエーテル系溶剤、ジアルキレングリコールアルキルエーテル系溶剤、トリアルキレングリコールアルキルエーテル系溶剤、１価アルコールエーテル系溶剤としては、例えば３−メチル−３−メトキシブタノールメチルエーテル、３−メチル−３−エトキシブタノールエチルエーテル、３−メチル−３−ｎ−ブトキシブタノールエチルエーテル、３−メチル−３−イソブトキシブタノールプロピルエーテル、３−メチル−３−ｓｅｃ−ブトキシブタノールーイソプロピルエーテル、３−メチル−３−ｔｅｒｔ−ブトキシブタノール−ｎ−ブチルエーテル等が挙げられる。
【００７６】
アルキレングリコールモノアルキルエーテル系溶剤としては、例えばプロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノプロピルエーテル、プロピレングリコールモノイソプロピルエーテル、プロピレングリコールモノ−ｎ−ブチルエーテル、プロピレングリコールモノイソブチルエーテル、プロピレングリコールモノ−ｓｅｃ−ブチルエーテル、プロピレングリコールモノ−ｔｅｒｔ−ブチルエーテル、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノプロピルエーテル、エチレングリコールモノイソプロピルエーテル、エチレングリコールモノ−ｎ−ブチルエーテル、エチレングリコールモノイソブチルエーテル、エチレングリコールモノ−ｓｅｃ−ブチルエーテル、エチレングリコールモノ−ｔｅｒｔ−ブチルエーテル等が挙げられる。
【００７７】
アルキレングリコールジアルキルエーテル系溶剤としては、例えばプロピレングリコールジメチルエーテル、プロピレングリコールジエチルエーテル、プロピレングリコールジプロピルエーテル、プロピレングリコールジイソプロピルエーテル、プロピレングリコールジ−ｎ−ブチルエーテル、プロピレングリコールジイソブチルエーテル、プロピレングリコールジ−ｓｅｃ−ブチルエーテル、プロピレングリコールジ−ｔｅｒｔ−ブチルエーテル、エチレングリコールジメチルエーテル、エチレングリコールジエチルエーテル、エチレングリコールジプロピルエーテル、エチレングリコールジイソプロピルエーテル、エチレングリコールジ−ｎ−ブチルエーテル、エチレングリコールジイソブチルエーテル、エチレングリコールジ−ｓｅｃ−ブチルエーテル、エチレングリコールジ−ｔｅｒｔ−ブチルエーテル等が挙げられる。
【００７８】
ジアルキレングリコールジアルキルエーテル系溶剤としては、例えばジプロピレングリコールジメチルエーテル、ジプロピレングリコールジエチルエーテル、ジプロピレングリコールジプロピルエーテル、ジプロピレングリコールジイソプロピルエーテル、ジプロピレングリコールジ−ｎ−ブチルエーテル、ジプロピレングリコールジイソブチルエーテル、ジプロピレングリコールジ−ｓｅｃ−ブチルエーテル、ジプロピレングリコールジ−ｔｅｒｔ−ブチルエーテル、ジエチレングリコールジメチルエーテル（ジグライム）、ジエチレングリコールジエチルエーテル、ジエチレングリコールジプロピルエーテル、ジエチレングリコールジイソプロピルエーテル、ジエチレングリコールジ−ｎ−ブチルエーテル、ジエチレングリコールジイソブチルエーテル、ジエチレングリコールジ−ｓｅｃ−ブチルエーテル、ジエチレングリコールジ−ｔｅｒｔ−ブチルエーテル等が挙げられる。
【００７９】
トリアルキレングリコールアルキルエーテル系溶剤としては、例えばトリプロピレングリコールジメチルエーテル、トリプロピレングリコールジエチルエーテル、トリジプロピレングリコールジプロピルエーテル、トリプロピレングリコールジイソプロピルエーテル、トリプロピレングリコールジ−ｎ−ブチルエーテル、トリプロピレングリコールジイソブチルエーテル、トリプロピレングリコールジ−ｓｅｃ−ブチルエーテル、トリプロピレングリコールジ−ｔｅｒｔ−ブチルエーテル、トリエチレングリコールジメチルエーテル、トリエチレングリコールジエチルエーテル、トリエチレングリコールジプロピルエーテル、トリエチレングリコールジイソプロピルエーテル、トリエチレングリコールジ−ｎ−ブチルエーテル、トリエチレングリコールジイソブチルエーテル、トリエチレングリコールジ−ｓｅｃ−ブチルエーテル、トリエチレングリコールジ−ｔｅｒｔ−ブチルエーテル等のアルキレングリコールジアルキルエーテル類等が挙げられる。
【００８０】
アセテート系溶剤としては、例えばエチレングリコールモノメチルエーテルアセテート、エチレングリコールモノエチルエーテルアセテート、エチレングリコールモノプロピルエーテルアセテート、エチレングリコールモノイソプロピルエーテルアセテート、エチレングリコールモノ−ｎ−ブチルエーテルアセテート、エチレングリコールモノイソブチルエーテルアセテート、エチレングリコールモノ−ｓｅｃ−ブチルエーテルアセテート、エチレングリコールモノ−ｔｅｒｔ−ブチルエーテルアセテート、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノエチルエーテルアセテート、プロピレングリコールモノプロピルエーテルアセテート、プロピレングリコールモノイソプロピルエーテルアセテート、プロピレングリコールモノ−ｎ−ブチルエーテルアセテート、プロピレングリコールモノイソブチルエーテルアセテート、プロピレングリコールモノ−ｓｅｃ−ブチルエーテルアセテート、プロピレングリコールモノ−ｔｅｒｔ−ブチルエーテルアセテート、３−メチル−３−メトキシブチルアセテート、３−メチル−３−エトキシブチルアセテート、３−メチル−３−プロポキシブチルアセテート、３−メチル−３−イソプロポキシブチルアセテート、３−メチル−３−ｎ−ブトキシブチルアセテート、３−メチル−３−イソブトキシブチルアセテート、３−メチル−３−ｓｅｃ−ブトキシブチルアセテート、３−メチル−３−ｔｅｒｔ−ブトキシブチルアセテート等のアルキレングリコールモノアルキルエーテルアセテート類、エチレングリコールジアセテート、ジエチレングリコールジアセテート、トリエチレングリコールジアセテート、プロピレングリコールジアセテート、ジプロピレングリコールジアセテート、トリプロピレングリコールジアセテート、酢酸ブチル等の溶媒が挙げられる。
【００８１】
溶剤の使用量は、液晶シール剤がディスペンサーあるいはスクリーン印刷等の方法で塗布できる。例えば、２００〜４００ポイズ（２５°Ｃ）に調整するのに必要な任意の量を用いることができ、通常、液晶シール剤中の不揮発成分が７０重量％以上、好ましくは８５〜９５重量％になるように使用する。
【００８２】
本発明の液晶シール剤は、前記したエポキシ樹脂、ノボラック樹脂、必要に応じて溶剤を添加し、加熱混合攪拌により溶解し、更に、充填剤、硬化促進剤、必要に応じカップリング剤、消泡剤、レベリング剤等の所定量を添加し、公知の混合装置、例えばボールミル、サンドミル、３本ロール等により混合することにより製造することができる。
【００８３】
本発明の液晶素子は、透過型の場合には、一対の透明基板間に液晶組成物を保持させ、両基板の周縁を上記シール剤で封止した素子である。透明基板の少なくとも一方の内面には透明電極又は液晶制御素子を備える。
【００８４】
透明基板としては、ガラス基板、石英基板、プラスッチク基板等を用いることができる。液晶制御素子としては、液晶の電気光学効果を制御する公知の素子を用いることができ、例えばアモルファスシリコンＴＦＴ、多結晶シリコンＴＦＴ、ＭＩＭ、ダイオード、結晶のＭＯＳＦＥＴ等を挙げることができる。反射型の場合には、上記基板の一方にシリコン基板を用いることができる。
【００８５】
図１は本発明による液晶表示素子の一例の構造を説明する要部断面模式図であって、１は薄膜トランジスタ等の液晶制御素子、２は画素電極、３はガラス基板（一方の基板、アクティブマトリクス基板）、４は対向するガラス基板（他方の基板、フィルタ基板）、５はカラーフィルタ、６，６’は配向膜を構成する有機高分子膜、７は透明電極、８はシール剤である。
【００８６】
下側のガラス基板３上に液晶制御素子１、画素電極２等が形成され、対向するガラス基板４上にブラックマトリクスで区画されてマトリックス状に配列された赤、緑、青色の三原色カラーフィルター５が形成される。
【００８７】
カラーフィルターは、染色法、印刷法、蒸着法、電着法、顔料分散法等の公知の方法で形成することができる。このカラーフィルター５上には、透明電極７を形成し、また、上記２枚の基板３，４の対向する少なくとも１枚の面に有機高分子膜を形成した後、所定の方向に液晶組成物が配向するようにラビング処理を行って配向膜を形成する。
【００８８】
そして、上記２枚のガラス基板を、それらの配向膜が対面するように重ね合わせ、一部に液晶の注入口を残して周縁にシール剤を介挿して接着硬化させて形成した両基板間の間隙に液晶組成物を注入した後、当該液晶注入口を封止して液晶表示素子を形成する。
【００８９】
図２は本発明の液晶表示素子の製造工程の貼り合わせ工程の概略説明図である。
【００９０】
同図において、１０は貼り合わせ工程、２０は第１加熱工程、３０は第２加熱工程、４０は冷却工程、５０は移載工程、６０は最終硬化工程である。
【００９１】
第１加熱工程２０、第１加熱工程２０、冷却工程３０には平面受け台２２、３２、４２の上面に掛け渡した搬送ベルト２１、３１、４１、および加圧部材２３、３３、４３、から構成されるプレス機構を有し、各工程において、搬送ベルト２１、３１、４１で上流から搬入される貼り合わせ済の２枚のガラス基板（以下、液晶パネルＰＮＬ）を加圧して加熱硬化、あるいは冷却させる。
【００９２】
先ず、２枚のガラス基板３と４は貼り合わせ工程１０において室温で重ね合わせられる。すなわち、基板４または３の周縁にシール剤を塗布する。このとき、周縁の一部にシール剤の非塗布部分を作り、液晶の注入口として残して置く。
【００９３】
貼り合わせたものを矢印Ａに示したように第１加熱工程２０に装入する、第１加熱工程２０では１６０〜１８０°Ｃで１〜３分間加熱しながら加圧してシール剤のプレ硬化とセルギャップ出しを行う。これをさらに第２加熱工程３０に移送して１６０〜１８０°Ｃで１〜３分間加熱を行ってシール剤の硬化を行う。
【００９４】
次に、シール剤の硬化を行った液晶パネルＰＮＬは冷却工程４０に移送され、２５°Ｃ〜４０°Ｃで１〜３分間加圧することにより２枚の基板の反りを矯正する。
【００９５】
冷却工程を経た液晶パネルＰＮＬは移載工程５０で移載機５１によりカセット５２に収納される。このカセット５２を最終硬化工程６０で最終硬化炉６１に入れ、１８０°Ｃで４０分間加熱することで、所謂キュアリングを行う。
【００９６】
本発明に用いる液晶組成物としては公知の液晶組成物を用いることができ、例えば、フッ素系、シアノ系、シクロヘキサン系、フェニルシクロヘキサン系、ビフェニル系、シッフベース系、強誘電性液晶、反強誘電性液晶等を挙げることができる。
【００９７】
本発明の液晶表示素子は、このような基板の一方にグラスファイバー等のスペーサー（間隙制御材）を添加後、基板の周縁に液晶組成物の注入口を残すように、スクリーン印刷、ディスペンサー塗布等の公知の方法でシール剤を塗布し、例えば１００°Ｃ、１０分間の加熱で溶剤を蒸発させ、もう一方の基板との間に所定の間隔（セルギャップ）を得られるように、例えばスペーサービーズをドライ分散、あるいはセミドライ分散等の公知の方法で分散させ、カラーフィルター５と液晶制御素子１の画素が対応するようにアライメントして両基板を重ね合わせ、次いで上下ガラス基板を貼り合わせ、プレスにてギャップ出しを行い、１６０〜１８０°Ｃで５０分加熱し硬化させる。
【００９８】
その後、上記注入口から液晶組成物９を注入して充填し、公知の封止剤を用いて注入口を封止することにより液晶表示素子が得られる。
【００９９】
このようにして得られた液晶表示素子は、接着性、耐湿性に優れ、また対液晶汚染性が低くため液晶の電気抵抗の低下が認められず、表示特性が優れたものとなる。
【０１００】
なお、上記スペーサーとしては、例えばグラスファイバー、ガラスビーズ等が挙げられる。その直径は、目的に応じ異なるが、通常２〜１０μｍ、好ましくは３．５〜７μｍである。また、その使用量は、溶剤を除く本発明の液晶シール剤１００重量部に対し０．１重量部、好ましくは０．５〜２重量部、更に好ましくは０．９〜１．５重量部程度である。
【０１０１】
［実施例］
以下、本発明を実施例により更に詳しく説明する。
【０１０２】
（実施例１）
液晶表示素子用シール剤の調整
エポキシ樹脂としてエポキシ当量が１８５の液状のビスフェノールＡ型エポキシ樹脂（ＲＥー３１０Ｓ、全塩素量５００ｐｐｍ、日本化薬製）１００ｇ、硬化剤として軟化点が５０°Ｃであるフェノールノボラック樹脂（ＰＮー１５２、日本化薬製）５４ｇを溶剤のプロピレングリコールモノエチルエーテルアセテート４０ｇに加熱溶解させる。
【０１０３】
この樹脂溶液に充填剤として粒径が３μｍ以下（平均粒径１．５μｍ以下）のシリカ３２ｇ、粒径が０．５μｍ以下（平均粒径０．５μｍ以下）のアルミナ８３ｇ、カップリング剤としてＮ−フェニル−γ−アミノプロピルトリメトキシシラン２０ｇを３本ロールにより混合分散し、硬化促進剤として平均粒径が３μｍ以下の２ＭＡＯＫ−ＰＷ（四国化成製）５ｇを、またギャップ形成のため７μｍのグラスファイバー１ｇを添加して本発明の液晶表示素子用シール剤を得た。
【０１０４】
液晶表示素子の作製
図１に示すように、ガラス基板上に画素電極、液晶制御素子１としてのアモルファスシリコンＴＦＴを形成し、その上にＰＡＳ膜をを形成した後、表面をラビング処理したアクティブマトリックス基板３と、ガラス基板上に三原色カラーフィルター５を形成し、その上に有機高分子膜６を塗布した後、表面をラビング処理した対向基板４を作製した。
【０１０５】
次に、本実施例で調整したシール剤８を対向基板４の周縁に、液晶組成物の注入口を残すようにディスペンサーを用いて塗布し、１００°Ｃで１０分間の加熱で溶剤揮発を行った後、カラーフィルター５と液晶制御素子（ＴＦＴ）の画素が対応するようにアライメントしてアクティブマトリックス基板３を重ね合わせた。重ね合わせた後、プレスにてギャップ出しを行い、１８０°Ｃ／２０分間加熱して硬化し、液晶セルを作製した。
【０１０６】
次に、液晶セルの注入口からフッ素系液晶組成物９（初期比抵抗４．２×１０¹³Ω・ｃｍ、ＮＩ点：７８°Ｃ）をセル内に充填した後、注入口から封止剤で封止して紫外線照射することにより硬化させて液晶表示素子を得た。
【０１０７】
得られた液晶表示素子について、電圧保持率、基板の接着強度の環境加速実験を評価した。また、シール剤が液晶に与える影響を調べるため、硬化したサンプルに液晶を浸し、その比抵抗測定を行なった。
【０１０８】
実施例１で調合したシール剤を、５ｃｃサンプル瓶に０．５ｇのシール剤をとり、１８０°Ｃで５０分間加熱して硬化させた。その硬化サンプルが入っている瓶にフッ素系液晶組成物９を２ｍｌ添加後，１００°Ｃで２０時間エージングしたものを測定した。結果を表１に示す。
【０１０９】
【表１】

【０１１０】
（実施例２〜５）、（比較例１、２）
実施例１で調整したシール剤の代わりに表２の処方に従って配合し、実施例１と同様にして本発明の実施例２〜５、又は比較例１、２の液晶表示素子を得、上記と同様に評価した。
【０１１１】
なお、比較例１、２のシール剤硬化時間は、温度は同じで時間のみが４時間で行った。この結果を表１に示す。
【０１１２】
【表２】

【０１１３】
表２の使用原料の説明
エポキシ樹脂
液状エポキシ樹脂Ａ：ビスフェノールＡ型エポキシ樹脂（ＲＥー３１０Ｓ 日本化薬製）
固体状エポキシ樹脂Ｂ：ビスフェノールＡ型エポキシ樹脂（エピコート１００１ 油化シェル製）
硬化剤
硬化剤Ａ：フェノールノボラック樹脂（ＰＮー１５２：二核体含有率４０％日本化薬製）
硬化剤Ｂ：フェノールノボラック樹脂（ＰＮー８０：二核体含有率１２％ 日本化薬製）
硬化剤Ｃ：２，４−ジアミノ−６−（２’−メチルイミダゾリル（１）’）エチル−ｓ−トリアジン・イソシアヌール酸付加物（２ＭＡＯＫーＰＷ 四国化成製）
硬化促進剤
硬化促進剤Ａ：２，４−ジアミノ−６−（２’−メチルイミダゾリル（１）’）エチル−ｓ−トリアジン・イソシアヌール酸付加物（２ＭＡＯＫーＰＷ 四国化成製）
アミンアダクト（平均粒径３μｍ以下） アミキュアＭＹ−Ｈ（味の素製）
２エチル４メチルイミダゾール ２Ｅ４ＭＺ（四国化成製）
溶剤
プロピレングリコールモノエチルエーテルアセテート
シランカップリング剤
Ｎ−フェニル−γ−アミノプロピルトリメトキシシラン（ＫＢＭ−５７３ 信越化学工業製）
表１から明らかなように、液晶セル製造時に上下ガラス基板の貼り合わせが常温で可能となり、かつ、多面取りに耐えられる接着強度と耐湿信頼性（−２０〜８０°Ｃ）に優れ、更に、可撓性に優れ、また、短時間で硬化が終了して所定のギャップが形成でき、かつ、硬化後のシール剤から液晶に対して汚染物質を流失させないことが分かる。
【０１１４】
図３は本発明によるシール剤の効果を温度対ゲル化時間の関係で示す説明図であって、白丸は前記実施例１のシール剤、黒丸は前記比較例１のシール剤である。
【０１１５】
図示したように、本発明のシール剤は短時間でゲル化するため、硬化時間が比較例よりも短縮され、所定のセルギャップが形成される。
【０１１６】
【発明の効果】
以上説明したように、本発明による液晶表示素子は、液晶表示素子の製造時に上下基板の貼り合わせを常温で実行することが可能となり、かつ、多面取りに耐えられる接着強度と耐湿信頼性（−２０〜８０°Ｃ）に優れ、更に、可撓性に優れ、また、短時間で硬化が終了して所定のギャップが形成でき、かつ、硬化後のシール剤から液晶に対して汚染物質を流失させるという従来技術の問題が解消される。
【０１１７】
更に、高温高湿下の通電試験、高温、低温の放置試験、及びヒートサイクル試験において十分な耐性を有する共に、熱応力に対してもクラッキング等を起こすこともなく液晶表示素子としての十分な信頼性を保持している。
【０１１８】
また、十分な接着強度が得られると同時に液晶組成物を劣化させることがないので、液晶の配向不良及び電気抵抗の低下が生じることがなく、表示特性が優れた液晶表示素子を提供することができる。
【図面の簡単な説明】
【図１】本発明による液晶表示素子の一例の構造を説明する要部断面模式図である。
【図２】本発明の液晶表示素子の製造工程の貼り合わせ工程の概略説明図である。
【図３】本発明によるシール剤の効果を温度対ゲル化時間の関係で示す説明図である。
【符号の説明】
１ 液晶制御素子
２ 画素電極
３ 基板
４ 対向基板
５ カラーフィルター
６ 絶縁膜
７ 透明電極
８ シール剤
９ 液晶組成物。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display element, and more particularly to a liquid crystal display element using a liquid crystal sealant that can easily bond two substrates and has improved adhesive strength, and a method for manufacturing the same.
[0002]
[Prior art]
Liquid crystal display devices are widely used as devices that display various images including still images and moving images.
[0003]
A liquid crystal display device is basically a liquid crystal display in which liquid crystal is sealed between two substrates, at least one of which is made of transparent glass, and the periphery of the substrate is bonded and fixed with a liquid crystal sealant. A type that integrates an element, a drive circuit, various optical sheets, a backlight, etc., and selectively turns on and off a predetermined pixel by selectively applying a voltage to various electrodes for pixel formation formed on the substrate ( A so-called simple matrix type, and a type (so-called thin film transistor (TFT)) that turns on and off a predetermined pixel by forming the above-mentioned various electrodes and a switching element for selecting a pixel as a liquid crystal control element and selecting the switching element. ) And the like.
[0004]
In particular, the latter active matrix type liquid crystal display devices have become the mainstream of liquid crystal display devices due to contrast performance, high-speed display performance, and the like.
[0005]
This active matrix type liquid crystal display device generally has a vertical electric field system in which an electric field for changing the alignment direction of a liquid crystal layer is applied between an electrode formed on one substrate and an electrode formed on the other substrate. However, recently, a lateral electric field type (In-Plane Switching Mode: IPS type) liquid crystal display device in which the direction of the electric field applied to the liquid crystal is substantially parallel to the substrate surface has been put into practical use.
[0006]
In producing a liquid crystal display element constituting such a liquid crystal display device, a liquid crystal sealant (hereinafter also simply referred to as a sealant) is applied to a glass substrate by a dispenser or a method such as screen printing, and is usually heated or After leveling without heating, the upper and lower substrates are bonded together by a process of bonding the upper and lower substrates with high precision using alignment marks and pressing a liquid crystal sealant.
[0007]
[Problems to be solved by the invention]
Currently, thermosetting epoxy resins are mainly used as the liquid crystal sealant used here. And what used amines, imidazoles, and hydrazides as the hardening | curing agent of this epoxy resin has the problem that it is inferior to adhesiveness and moisture-proof reliability.
[0008]
As a method for solving this problem, Japanese Patent Publication No. 59-24403 discloses a liquid crystal sealing agent in which a phenol novolac resin is used as a curing agent for an epoxy resin and a solvent is added to make the coating liquid liquid. This liquid crystal sealant has been shown to be excellent in moisture resistance.
[0009]
However, this liquid crystal sealant uses a phenol novolac resin having a trinuclear body or more, and when the upper and lower substrates are bonded using this, the softening point of the phenol novolac resin is a solid having a softening point of 80 ° C. or more. For this reason, since the resin component of the sealant is usually solidified in the process of removing the solvent, the upper and lower substrates must be heated to melt the sealant for bonding.
[0010]
In recent years, substrates for liquid crystal display elements have become increasingly larger, and when bonded together while heating, the upper and lower substrates can be moved with high accuracy due to the difference in temperature expansion between the upper and lower substrates and the difference in thermal expansion depending on the location of the substrates. It has become difficult to attach the substrates.
[0011]
As a method for solving this problem, a method of laminating a glass substrate at room temperature is considered, but a sealant that can be bonded at room temperature using a liquid crystal sealant having a phenol novolac resin as a curing agent is still known. Absent.
[0012]
Furthermore, recent liquid crystal display elements have a multi-processing process in which a large number of electrodes are formed on a large substrate, and then assembled by laminating upper and lower substrates, and then divided into individual liquid crystal display elements (also referred to as liquid crystal cells). However, the number of processed sheets has been increased from the conventional one-sheet picking to two-piece picking, four-piece picking, six-piece picking, nine-piece picking, and the like.
[0013]
Furthermore, in recent years, since the individual liquid crystal display elements themselves are becoming larger and larger, there has been a problem that the seal part is peeled off when a strong force is applied to the seal part during the multi-processing process.
[0014]
In order to solve this problem, a sealant excellent in adhesiveness and flexibility is required. However, conventional sealants using amines, imidazoles, and hydrazides as curing agents are inferior in adhesiveness. Since a sealing agent using a phenol novolac resin of a nucleus or higher as a curing agent has a drawback of being hard and brittle, it cannot cope with an increase in the size of a substrate and an increase in the size of a liquid crystal display element.
[0015]
Further, since the length of the seal line has been increased with the increase in the size of the liquid crystal display element, the substrate is also excellent in moisture resistance reliability and the line width of the seal is reduced (0.2 to 1.5 mm). There is a demand for a sealing agent that is excellent in adhesiveness and excellent in flexibility.
[0016]
Further, there is a demand for a sealant that can be cured in a short time in the seal forming step. Further, after the sealing agent is crosslinked and cured, liquid crystal is injected between the substrates. Since the injected liquid crystal and the sealing agent are in contact with each other, contaminants flow out from the sealing agent into the liquid crystal. Development of a sealant that does not cause a decrease in the specific resistance of liquid crystal is demanded.
[0017]
Further, regarding the workability in the coating process of the sealing agent, there is a demand for a sealing agent that has a small increase in viscosity and has a long usable time (life: pot life).
[0018]
In addition, a sealing agent that does not have to be degassed to remove bubbles in the sealing agent after being kneaded with glass fiber or the like added as a filler for forming a gap at a predetermined interval of the sealing agent. Is required.
[0019]
Accordingly, the object of the present invention is to provide excellent adhesive strength and moisture resistance reliability (-20 to 80 ° C.) capable of bonding the upper and lower substrates at room temperature during the production of the liquid crystal liquid crystal element, Furthermore, it is excellent in flexibility, can be cured in a short time, can form a predetermined gap, and does not cause contaminants to flow away from the cured sealant to the liquid crystal. A liquid crystal display element using a liquid crystal sealing agent that is added to form a gap of, for example, kneading with glass fiber and does not need to be deaerated to remove bubbles in the sealing agent, and It is to provide a manufacturing method.
[0020]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have configured the present invention as follows. That is, the present invention
(1) One substrate having at least a liquid crystal control element and a pixel electrode, and the other substrate having at least a color filter are arranged to face each other at a predetermined interval, and are fixed with a liquid crystal sealant interposed at the periphery. In a liquid crystal display element having a liquid crystal sandwiched between gaps,
The liquid crystal sealing agent is (a) a liquid epoxy resin, (b) a curing agent comprising a novolac resin having a softening point of 75 ° C. or less by the ring and ball method, (c) a filler having a particle size of 10 μm or less, and (d) The curing accelerator is an essential component, and the mixture of the component (a) and the component (b) is liquid or has a softening point of 50 ° C. or less as measured by the ring and ball method.
[0021]
(2) The total chlorine content in the component (a) in (1) was set to 1500 ppm or less.
[0022]
(3) The liquid epoxy resin (a) in either (1) or (2) was a bisphenol A liquid epoxy resin and / or a bisphenol F liquid epoxy resin.
[0023]
(4) The novolac resin in which the curing agent (b) in any one of (1) to (3) contains 20 to 80% by weight of a binuclear body.
[0024]
(5) The average particle diameter of the filler of (c) in any one of (1) to (4) was 2 μm or less.
[0025]
(6) The content of the filler (c) in any one of (1) to (5) is 5 to 30% by volume in the liquid crystal sealant. .
[0026]
(7) The filler of (c) in any one of (1) to (6) was alumina and / or silica.
[0027]
(8) The curing accelerator (d) in any one of (1) to (7) was used as a latent curing accelerator.
[0028]
(9) The latent curing accelerator in (8) is a solid dispersion type imidazole, and its average particle size is 6 μm or less.
[0029]
(10) The latent curing accelerator in (8) is an amine adduct and has an average particle size of 6 μm or less.
[0030]
(11) A coupling agent is contained in the liquid crystal sealant in (1) to (10).
[0031]
(12) The coupling agent contained in the liquid crystal sealant according to any one of (1) to (10) is an aminosilane coupling agent.
[0032]
(13) One substrate having at least a liquid crystal control element and a pixel electrode and the other substrate having at least a color filter are arranged to face each other at a predetermined interval, and a liquid crystal sealant is inserted around the periphery excluding the liquid crystal composition injection port. The liquid crystal display element is manufactured by injecting a liquid crystal composition from the liquid crystal injection port and sandwiching the liquid crystal in the gap between the two substrates to obtain a liquid crystal display element. And
As the liquid crystal sealant, (a) a liquid epoxy resin, (b) a curing agent made of a novolak resin having a softening point of 75 ° C. or less by the ring and ball method, (c) a filler having a particle size of 10 μm or less, and (d) A curing accelerator is an essential component, and the mixture of the component (a) and the component (b) is liquid or has a softening point of 50 ° C. or less as measured by the ring and ball method, and is 160 to 180 ° C. A liquid crystal sealant having a curing time of 50 minutes or less was used.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0034]
A liquid crystal display element according to the present invention is a liquid crystal display element having a sealant for sandwiching a liquid crystal between a pair of transparent substrates, such as a pair of glass and the like, and sandwiching the liquid crystal between the pair of substrates. (A) liquid epoxy resin, (b) a curing agent made of a novolak resin having a softening point of 75 ° C. or less by the ring and ball method, (c) a filler having a particle size of 10 μm or less, and (d) a curing accelerator. The component is characterized in that the mixture of the component (a) and the component (b) is liquid or has a softening point of 50 ° C. or less as measured by the ring and ball method.
[0035]
The liquid epoxy resin (a) used in the present invention is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, N, N-diglycidyl-0-toluidine, N, N- Diglycidyl aniline, phenyl glycidyl ether, resorcinol cidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polypropylene glycol diglycidyl ether, (3,4-4-3 ′, 4 ′ epoxycyclo) hexylmethyl Although generally produced and sold epoxy resins such as hexanecarboxylate, hexahydrophthalic anhydride diglycidyl ester, and the like, bisphenol A type epoxy resin, bisphenol F type epoxy resin, , N-diglycidyl-o-toluidine, N, N-diglycidylaniline, (3,4-3 ′, 4′epoxycyclo) hexylmethylhexanecarboxylate, hexahydrophthalic anhydride diglycidyl ester, more preferably bisphenol A type epoxy resin and / or bisphenol F type epoxy resin.
[0036]
These liquid epoxy resins may be used in combination of two or more. Since these liquid epoxy resins are liquid at room temperature, the resin viscosity of the liquid crystal sealant when the upper and lower glass substrates are bonded at the time of manufacturing the liquid crystal cell is low, enabling bonding at room temperature and easy gap formation. Become.
[0037]
The epoxy equivalent of the liquid epoxy resin used in the present invention is 230 or less, preferably 210 or less, more preferably 190 or less. If it is 230 or more, the reactivity with the curing agent is inferior, and there is a problem in workability.
[0038]
Moreover, the total chlorine amount of the liquid epoxy resin used for this invention is 1500 ppm or less, Preferably it is 1200 or less, More preferably, it is 1000 or less. When the total chlorine amount is 1500 or more, the ITO electrode of the liquid crystal element is significantly corroded. The epoxy equivalent is measured by JIS K7236, and the total chlorine content is measured by a hydrolysis method (the same applies hereinafter).
[0039]
The curing agent (b) used in the present invention is a novolak resin having a softening point by a ring and ball method of usually 75 ° C. or lower, preferably 65 ° C. or lower, more preferably 50 ° C. or lower. A novolak resin using a compound having a hydroxyl group as a raw material is preferable. The softening point is measured by the ring and ball method defined in JIS K7234.
[0040]
Examples of the novolak resin include bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, 2,2 ′, 6,6′-tetramethyl-4,4′-biphenylphenol, 2 , 2'-methylene-bis (4-methyl-6-tert-butylphenol), trishydroxyphenylmethane, pyrogallol, phenols having a diisopropylidene skeleton, fluorene skeletons such as 1,1-di-4-hydroxyphenylfluorene Phenols, polyphenol compounds such as phenolized polybutadiene, phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, brominated bisphenol A, bisphenol F, bisphenol Examples thereof include novolak resins made of various phenols such as Nord S and naphthols, xylylene skeleton-containing phenol novolak resins, dicyclopentadiene skeleton-containing phenol novolak resins, and fluorene skeleton-containing phenol novolak resins. Preferably, novolak resin, xylylene skeleton-containing phenol novolak resin, dicyclopentadiene skeleton made from various phenols such as phenol, cresol, ethylphenol, butylphenol, octylphenol, bisphenol A, bisphenol F, bisphenol S, naphthol Various novolak resins such as a phenol novolac resin containing phenol, a fluorene skeleton containing phenol novolac resin, more preferably phenol, Various novolak resins such as novolak resins made from various phenols such as resoles, octylphenol, bisphenol A, bisphenol F, bisphenol S, naphthols, etc., particularly preferably phenol novolak resins and cresols made from phenol It is a cresol novolac resin used as a raw material.
[0041]
These novolak resins are used alone or in admixture of two or more. Moreover, the usage-amount of the novolak resin used by this invention is 0.6-1.4 chemical equivalent as the equivalent of the hydroxyl group in a novolak resin with respect to the epoxy equivalent of the epoxy resin in a sealing agent, Preferably it is 0.8. 9 to 1.11 chemical equivalents.
[0042]
In addition, the novolak resin is usually obtained from the production process as a mixture of a binuclear body having two phenolic hydroxyl groups in the molecule and a product having three or more phenolic hydroxyl groups in the molecule.
[0043]
The preferred phenolic novolak resin used in the present invention has a binuclear content of 20 to 80% by weight, preferably 25 to 70% by weight, more preferably 30 to 50% by weight.
[0044]
A preferred novolak resin used in the present invention is a novolak made of monophenols as a raw material, and has the following general formula:
[0045]
[Chemical 1]

[0046]
(In the above formula, R represents hydrogen, lower alkyl, lower alkoxy or halogen, m represents an integer of 1 to 3, and when m is 2 or 3, R may be a different type. 0 or a positive integer).
[0047]
In the above formula, examples of the lower alkyl include C1-C4 alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and t-butyl, and examples of the lower alkoxy include methoxy, ethoxy, n- Examples of the halogen of C1-C4 alkoxy such as propoxy, isopropoxy, n-butoxy, isobutoxy, t-butoxy and the like include bromine. The positive integer in n is preferably 1-10.
[0048]
The curing agent comprising a phenolic novolak resin used in the present invention preferably has a component where n = 0 in the compound represented by the above formula because a component where n = 1 or higher has a high softening point. The amount thereof is usually 20 to 80% by weight, preferably 25 to 70% by weight, more preferably about 30 to 50% by weight in the novolak resin (the rest is a component where n = 1 or more).
[0049]
The mixture of the phenolic novolac resin and the liquid epoxy resin is preferably liquid at room temperature or has a softening point of 50 ° C. or less as measured by the ring and ball method.
[0050]
Further, the curing agent composed of a phenolic novolak resin used in the present invention is excellent in adhesion to a glass substrate and moisture resistance reliability, preferably in combination with a liquid epoxy resin having an epoxy equivalent of 230 or less.
[0051]
In the reaction of a phenolic novolak resin with an epoxy resin, a phenol novolac resin having a binuclear structure (for example, a compound having n = 0 in the above formula) is a trinuclear compound or more (for example, a compound having n = 1 in the above formula). Since the three-dimensional cross-linked structure obtained by curing the phenol novolac hardener is linearly cross-linked, the rigid structure is flexible, and thus the adhesion to the glass substrate is improved.
[0052]
Furthermore, since the phenol novolac resin used in the present invention has a softening point as low as 75 ° C. or lower, the resin viscosity of the liquid crystal sealant during the process of laminating the upper and lower glass substrates during liquid crystal element production becomes low, and the laminating, Gaps can be easily formed. Examples of the filler (c) used in the present invention include fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, and oxidation. Magnesium, zirconium oxide, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably molten Silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, aluminum silicate, more preferably fused silica, Silica, alumina.
[0053]
These fillers may be used as a mixture of two or more, and particularly preferably when silica and alumina are used in combination.
[0054]
The maximum particle size of the filler used in the present invention is 10 μm or less, preferably 6 μm or less, more preferably 4 μm or less, particularly preferably 4 μm or less, and its average particle size is 2 μm or less as measured by the laser method. It is.
[0055]
When the particle size of the filler is larger than 10 μm, the gap cannot be formed well after the upper and lower substrates are bonded at the time of manufacturing the liquid crystal display element. Such filler silica is produced, for example, by grinding and classifying fused silica or crystalline silica.
[0056]
Alumina is produced, for example, by pulverizing and classifying alumina obtained by calcining aluminum hydroxide or alumina obtained by flame hydrolysis of anhydrous aluminum chloride or alumina alum.
[0057]
Content in the liquid-crystal sealing compound of the filler used by this invention is 5-30 volume% in a liquid-crystal sealing compound except a solvent, More preferably, it is 15-25 volume%.
[0058]
When the content of the filler is lower than 5% by volume, the amount of the filler is small, so the viscosity becomes low. After application of the liquid crystal sealant, it tends to sag and repel on the glass substrate, and the seal shape may be disturbed. . Moreover, when there is more content of a filler than 30 volume%, since there is too much filler content, it is hard to be crushed and it will become impossible to form the gap of a liquid crystal display element.
[0059]
Examples of the curing accelerator (d) used in the present invention include imidazoles, imidazoles and phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, maleic acid, and oxalic acid. Salts with monovalent carboxylic acids, amides such as dicyandiamide, and salts of the amides with phenols, the polyvalent carboxylic acids or phosphinic acids, 1,8-diaza-bicyclo (5.4.0) undecene-7 And diaza compounds such as diaza compounds and phenols, the polyvalent carboxylic acids, phosphinic acids, phosphines such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, and phenols such as 2,4,6-trisaminomethylphenol And amine adducts.
[0060]
Examples of imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2- Methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2′-methylimidazole (1 ′)) ethyl- s-triazine, 2,4-diamino-6 (2'-undecylimidazole (1 ')) ethyl-s-triazine, 2,4-diamino-6 (2'-ethyl, 4-methylimidazole (1') ) Ethyl-s-triazine, 2,4-diamino-6 (2'-methyl) Imidazole (1 ′)) ethyl-s-triazine isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3, 5-dihydroxymethylimidazole 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3, 5-dicyanoethoxymethylimidazole and the like.
[0061]
Among these curing accelerators, for example, 2,4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine-isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2 : 3-adduct, 2-phenylimidazole isocyanuric acid adduct, imidazoles and polyvalent carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, maleic acid, and oxalic acid Examples thereof include salts and amine adducts.
[0062]
The addition amount of a hardening accelerator is 0.5-20 weight part with respect to 100 weight part of epoxy resins, Preferably it is 1-10 weight part.
[0063]
These curing accelerators are preferably used in the form of latent curing accelerators because they have advantages such as improved workability (extension of pot life time).
[0064]
The latent curing accelerator is solid at room temperature, has a property of dissolving when heated, and reacts as a curing accelerator for the first time. For example, a microcapsule type curing accelerator in which these curing accelerators are microcapsules, Examples thereof include solid dispersion type curing accelerators (for example, imidazoles) that are hardly dissolved in a solvent or an epoxy resin, and amine adducts.
[0065]
Among these curing accelerators, the average particle size of the solid dispersion type latent curing accelerator is about 6 μm or less, preferably about 4 μm or less, more preferably about 3 μm or less as measured by a laser method. When a latent curing accelerator having an average particle size of more than 6 μm is used, it is difficult to apply the dispenser, and the shape after application is not uniform, and therefore the seal shape after sealing is not uniform.
[0066]
Moreover, the rough coarseness of a filler is confirmed in the seal | sticker part after sealing of the liquid-crystal sealing compound which uses a hardening accelerator with an average particle diameter larger than 6 micrometers.
[0067]
The liquid crystal sealant of the present invention includes the above liquid epoxy resin (a), a curing agent (b) composed of a novolac resin having a softening point of 75 ° C. or less by the ring and ball method, a filler (c) having a particle size of 10 μm or less, and The curing accelerator (d) is an essential component, and the softening point of the (molten) mixture of the component (a) and the component (b) is 50 ° C. or less, preferably 40 ° C. or less, more preferably 30 as measured by the ring and ball method. It is characterized by being in a liquid state at room temperature or less, more preferably at room temperature. When the softening point is higher than 50 ° C, a solvent is used to form a liquid crystal sealing agent. In this case, the sealing agent after the solvent volatilization becomes solid, and the upper and lower glass substrates are bonded to each other at the time of manufacturing the liquid crystal element. Since the liquid crystal sealant is not crushed at room temperature when the upper and lower glass substrates are bonded to each other without heating the upper and lower glass substrates, the liquid crystal cell cannot be manufactured.
[0068]
When the liquid crystal sealing agent of the present invention is liquid at room temperature, its viscosity is suitably about 200 to 400 poise (25 ° C.) in consideration of workability. Further, the thixotropy is suitably about 0.8 to 1.1.
[0069]
1 type (s) or 2 or more types of solid epoxy resins can be added to the liquid-crystal sealing compound of this invention. Examples of the solid epoxy resin used include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, 2,2 ′, 6,6′-tetramethyl-4,4′-biphenylphenol, and 2,2 ′. -Methylene-bis (4-methyl-6-tert-butylphenol), trishydroxyphenylmethane, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene , Polyfunctional epoxy resins that are glycidyl etherified products of polyphenol compounds such as phenolized polybutadiene, phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, tetrabromobisphenol Glycidyl ethers of various novolak resins such as novolak resin, xylylene skeleton-containing phenol novolak resin, dicyclopentadiene skeleton-containing phenol novolak resin, fluorene skeleton-containing phenol novolak resin, etc. , Cycloaliphatic alicyclic epoxy resin having an aliphatic skeleton, isocyanuric ring, heterocyclic epoxy resin having a heterocyclic ring such as hydantoin ring, brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated Examples include epoxy resins obtained by glycidylation of brominated phenols such as phenol novolac and brominated cresol novolac, and the amount used affects the melting point, workability and physical properties of the resulting sealant. Used in a range which does not give.
[0070]
The total chlorine content of the solid epoxy resin is 1500 ppm or less, preferably 1200 or less, and more preferably 1000 or less. When the total chlorine amount is 1500 or more, corrosion of the ITO electrode of the liquid crystal cell becomes significant.
[0071]
A coupling agent can be added to the liquid crystal sealant of the present invention. As the coupling agent, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-amino Propyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3 -Black Silane coupling agents such as propylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane, isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium (dioctyl pyrophosphate) oxyacetate, tetraisopropyldi (Dioctyl phosphite) titanate, titanium-based coupling agents such as neoalkoxytri (pN- (β-aminoethyl) aminophenyl) titanate, Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, neoalkoxyzirco , Neoalkoxytris neodecanoyl zirconate, neoalkoxytris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxytris (ethyl) Diaminoethyl) zirconate, neoalkoxy tris (m-aminophenyl) zirconate, ammonium zirconium carbonate, zirconium such as A1-acetylacetonate, A1-methacrylate, A1-propionate, or aluminum coupling agents are preferable, Silicon coupling agents are preferred, and aminosilane coupling agents are more preferred.
[0072]
By using a coupling agent, a liquid crystal sealant having excellent moisture resistance reliability and little decrease in adhesive strength after moisture absorption can be obtained.
[0073]
In the liquid crystal sealant of the present invention, a solvent may be added to lower the viscosity and improve workability. Examples of the solvent that can be used include alcohol solvents, ether solvents, and acetate solvents. These may be used alone or in combination of two or more thereof in any ratio.
[0074]
Examples of alcohol solvents include alkyl alcohols such as ethanol and isopropyl alcohol, 3-methyl-3-methoxybutanol, 3-methyl-3-ethoxybutanol, 3-methyl-3-n-propoxybutanol, and 3-methyl- Examples include alkoxy alcohols such as 3-n-butoxybutanol, 3-methyl-3-isobutoxybutanol, 3-methyl-3-sec-butoxybutanol, and 3-methyl-3-tert-butoxybutanol.
[0075]
Examples of ether solvents include monohydric alcohol ether solvents, alkylene glycol monoalkyl ether solvents, alkylene glycol dialkyl ether solvents, dialkylene glycol alkyl ether solvents, trialkylene glycol alkyl ether solvents, monohydric alcohol ether solvents. Examples of the solvent include 3-methyl-3-methoxybutanol methyl ether, 3-methyl-3-ethoxybutanol ethyl ether, 3-methyl-3-n-butoxybutanol ethyl ether, 3-methyl-3-isobutoxybutanol propyl. Examples include ether, 3-methyl-3-sec-butoxybutanol-isopropyl ether, and 3-methyl-3-tert-butoxybutanol-n-butyl ether.
[0076]
Examples of the alkylene glycol monoalkyl ether solvent include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol mono-n-butyl ether, propylene glycol monoisobutyl ether, propylene glycol Mono-sec-butyl ether, propylene glycol mono-tert-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether Ethylene glycol monobutyl -sec- butyl ether, and ethylene glycol monobutyl -tert- butyl ether.
[0077]
Examples of the alkylene glycol dialkyl ether solvent include propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol diisopropyl ether, propylene glycol di-n-butyl ether, propylene glycol diisobutyl ether, propylene glycol di-sec-butyl ether. , Propylene glycol di-tert-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol diisopropyl ether, ethylene glycol di-n-butyl ether, ethylene glycol diisobutyl ether, ethylene glycol di-sec Ether, and ethylene glycol di -tert- butyl ether.
[0078]
Dialkylene glycol dialkyl ether solvents include, for example, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dipropyl ether, dipropylene glycol diisopropyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol diisobutyl ether, Dipropylene glycol di-sec-butyl ether, dipropylene glycol di-tert-butyl ether, diethylene glycol dimethyl ether (diglyme), diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol diisopropyl ether, diethylene glycol di-n-butyl ether, diethylene glycol diiso Chirueteru, diethylene glycol di -sec- butyl ether, diethylene glycol di -tert- butyl ether, and the like.
[0079]
Examples of the trialkylene glycol alkyl ether solvent include tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tridipropylene glycol dipropyl ether, tripropylene glycol diisopropyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol diisobutyl ether, Tripropylene glycol di-sec-butyl ether, tripropylene glycol di-tert-butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropyl ether, triethylene glycol diisopropyl ether, triethylene glycol di-n-butyl ether , Triethylene Recall diisobutyl ether, triethylene glycol di -sec- butyl ether, alkylene glycol dialkyl ethers such as triethylene glycol di -tert- butyl ether, and the like.
[0080]
Examples of acetate solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol monoisobutyl ether acetate, Ethylene glycol mono-sec-butyl ether acetate, ethylene glycol mono-tert-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monoisopropyl ether acetate, Pyrene glycol mono-n-butyl ether acetate, propylene glycol monoisobutyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-tert-butyl ether acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3- Ethoxybutyl acetate, 3-methyl-3-propoxybutyl acetate, 3-methyl-3-isopropoxybutyl acetate, 3-methyl-3-n-butoxybutyl acetate, 3-methyl-3-isobutoxybutyl acetate, 3- Alkylene glycol monoalkyl ether acetates such as methyl-3-sec-butoxybutyl acetate and 3-methyl-3-tert-butoxybutyl acetate; Call diacetate, diethylene glycol diacetate, triethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, tripropylene glycol diacetate, include solvents such as butyl acetate.
[0081]
As for the amount of the solvent used, the liquid crystal sealant can be applied by a method such as dispenser or screen printing. For example, any amount necessary to adjust to 200 to 400 poise (25 ° C.) can be used, and usually the non-volatile component in the liquid crystal sealant is 70% by weight or more, preferably 85 to 95% by weight. Use to be.
[0082]
The liquid crystal sealant of the present invention includes the above-described epoxy resin, novolak resin, a solvent as necessary, and is dissolved by heating, mixing and stirring, and further, a filler, a curing accelerator, a coupling agent as necessary, and an antifoaming agent It can be produced by adding a predetermined amount of an agent, a leveling agent, etc., and mixing them with a known mixing device such as a ball mill, a sand mill, a three roll or the like.
[0083]
In the case of the transmissive type, the liquid crystal element of the present invention is an element in which a liquid crystal composition is held between a pair of transparent substrates and the peripheral edges of both substrates are sealed with the above-described sealing agent. A transparent electrode or a liquid crystal control element is provided on at least one inner surface of the transparent substrate.
[0084]
As the transparent substrate, a glass substrate, a quartz substrate, a plastic substrate, or the like can be used. As the liquid crystal control element, a known element for controlling the electro-optic effect of the liquid crystal can be used, and examples thereof include an amorphous silicon TFT, a polycrystalline silicon TFT, an MIM, a diode, and a crystal MOSFET. In the case of the reflection type, a silicon substrate can be used for one of the substrates.
[0085]
FIG. 1 is a schematic cross-sectional view of an essential part for explaining the structure of an example of a liquid crystal display device according to the present invention. 1 is a liquid crystal control element such as a thin film transistor, 2 is a pixel electrode, and 3 is a glass substrate (one substrate, active matrix). Substrate), 4 is an opposing glass substrate (the other substrate, filter substrate), 5 is a color filter, 6 and 6 'are organic polymer films constituting an alignment film, 7 is a transparent electrode, and 8 is a sealant.
[0086]
The liquid crystal control element 1, the pixel electrode 2 and the like are formed on the lower glass substrate 3, and the three primary color filters 5 of red, green, and blue arranged in a matrix on the opposite glass substrate 4 partitioned by a black matrix. Is formed.
[0087]
The color filter can be formed by a known method such as a dyeing method, a printing method, a vapor deposition method, an electrodeposition method, or a pigment dispersion method. A transparent electrode 7 is formed on the color filter 5 and an organic polymer film is formed on at least one surface of the two substrates 3 and 4 facing each other, and then a liquid crystal composition in a predetermined direction. The alignment film is formed by performing a rubbing process so as to align.
[0088]
Then, the two glass substrates are overlapped so that their alignment films face each other, and a liquid crystal injection port is left in a part, and a sealant is inserted in the periphery to bond and cure between the two substrates. After injecting a liquid crystal composition into the gap, the liquid crystal injection port is sealed to form a liquid crystal display element.
[0089]
FIG. 2 is a schematic explanatory view of a bonding process in the manufacturing process of the liquid crystal display element of the present invention.
[0090]
In the figure, 10 is a bonding process, 20 is a first heating process, 30 is a second heating process, 40 is a cooling process, 50 is a transfer process, and 60 is a final curing process.
[0091]
In the first heating step 20, the first heating step 20, and the cooling step 30, the conveyor belts 21, 31, 41 and the pressure members 23, 33, 43, which are stretched over the upper surfaces of the flat pedestals 22, 32, 42, are used. A press mechanism configured, and in each process, pressurize and heat cure two bonded glass substrates (hereinafter referred to as liquid crystal panel PNL) that are carried from the upstream by the conveyor belts 21, 31, 41, or Allow to cool.
[0092]
First, the two glass substrates 3 and 4 are superposed at room temperature in the bonding step 10. That is, a sealing agent is applied to the periphery of the substrate 4 or 3. At this time, a non-coated portion of the sealant is formed on a part of the peripheral edge and left as a liquid crystal injection port.
[0093]
As shown by the arrow A, the pasted material is charged into the first heating step 20. In the first heating step 20, pressure is applied while heating at 160 to 180 ° C. for 1 to 3 minutes, and the precuring of the sealing agent is performed. Perform cell gap. This is further transferred to the second heating step 30 and heated at 160 to 180 ° C. for 1 to 3 minutes to cure the sealant.
[0094]
Next, the liquid crystal panel PNL on which the sealing agent has been cured is transferred to the cooling step 40, and the warpage of the two substrates is corrected by pressurizing at 25 ° C. to 40 ° C. for 1 to 3 minutes.
[0095]
The liquid crystal panel PNL that has undergone the cooling process is stored in the cassette 52 by the transfer machine 51 in the transfer process 50. The cassette 52 is placed in a final curing furnace 61 in a final curing step 60 and heated at 180 ° C. for 40 minutes to perform so-called curing.
[0096]
As the liquid crystal composition used in the present invention, a known liquid crystal composition can be used. For example, fluorine, cyano, cyclohexane, phenylcyclohexane, biphenyl, Schiff base, ferroelectric liquid crystal, antiferroelectric property A liquid crystal etc. can be mentioned.
[0097]
In the liquid crystal display element of the present invention, after adding a spacer (gap control material) such as glass fiber to one of such substrates, screen printing, dispenser coating, etc. so as to leave a liquid crystal composition inlet at the periphery of the substrate. For example, spacer beads are used so that a predetermined gap (cell gap) can be obtained between the other substrate by evaporating the solvent by, for example, heating at 100 ° C. for 10 minutes. Is dispersed by a known method such as dry dispersion or semi-dry dispersion, aligned so that the pixels of the color filter 5 and the liquid crystal control element 1 correspond to each other, and both substrates are overlapped, and then the upper and lower glass substrates are bonded together, and pressed Gap out and heat at 160-180 ° C. for 50 minutes to cure.
[0098]
Thereafter, the liquid crystal composition 9 is injected and filled from the injection port, and the injection port is sealed using a known sealing agent, whereby a liquid crystal display element is obtained.
[0099]
The liquid crystal display element thus obtained is excellent in adhesiveness and moisture resistance, and has a low resistance to liquid crystal, so that a decrease in the electrical resistance of the liquid crystal is not observed, and the display characteristics are excellent.
[0100]
Examples of the spacer include glass fiber and glass beads. The diameter varies depending on the purpose, but is usually 2 to 10 μm, preferably 3.5 to 7 μm. The amount used is 0.1 parts by weight, preferably 0.5 to 2 parts by weight, more preferably about 0.9 to 1.5 parts by weight, based on 100 parts by weight of the liquid crystal sealant of the present invention excluding the solvent. It is.
[0101]
[Example]
Hereinafter, the present invention will be described in more detail with reference to examples.
[0102]
(Example 1)
Adjustment of sealant for liquid crystal display elements
100 g of liquid bisphenol A type epoxy resin (RE-310S, total chlorine amount 500 ppm, manufactured by Nippon Kayaku Co., Ltd.) having an epoxy equivalent of 185 as an epoxy resin, and a phenol novolac resin (PN-152) having a softening point of 50 ° C. as a curing agent. (Manufactured by Nippon Kayaku Co., Ltd.) is dissolved in 40 g of propylene glycol monoethyl ether acetate as a solvent by heating.
[0103]
In this resin solution, 32 g of silica having a particle size of 3 μm or less (average particle size of 1.5 μm or less) as a filler, 83 g of alumina having a particle size of 0.5 μm or less (average particle size of 0.5 μm or less), and N as a coupling agent -20 g of phenyl-γ-aminopropyltrimethoxysilane was mixed and dispersed by three rolls, 5 g of 2MAOK-PW (manufactured by Shikoku Kasei) having an average particle size of 3 μm or less as a curing accelerator, and a glass of 7 μm for forming a gap. 1 g of fiber was added to obtain a sealing agent for liquid crystal display elements of the present invention.
[0104]
Production of liquid crystal display elements
As shown in FIG. 1, after forming an amorphous silicon TFT as a pixel electrode and a liquid crystal control element 1 on a glass substrate and forming a PAS film thereon, an active matrix substrate 3 whose surface is rubbed, and a glass After forming the three primary color filters 5 on the substrate and coating the organic polymer film 6 thereon, the counter substrate 4 whose surface was rubbed was produced.
[0105]
Next, the sealant 8 prepared in this example was applied to the peripheral edge of the counter substrate 4 using a dispenser so as to leave an injection port for the liquid crystal composition, and the solvent was volatilized by heating at 100 ° C. for 10 minutes. After that, the active matrix substrate 3 was overlaid by aligning the color filter 5 and the liquid crystal control element (TFT) pixels so as to correspond to each other. After superposition, gaps were made with a press and cured by heating at 180 ° C./20 minutes to produce a liquid crystal cell.
[0106]
Next, the fluorine-based liquid crystal composition 9 (initial specific resistance 4.2 × 10 6 is introduced from the injection port of the liquid crystal cell.¹³(Ω · cm, NI point: 78 ° C.) was filled in the cell, sealed with a sealant from the inlet, and cured by irradiation with ultraviolet rays to obtain a liquid crystal display element.
[0107]
About the obtained liquid crystal display element, the environmental acceleration experiment of voltage holding ratio and the adhesive strength of a board | substrate was evaluated. Moreover, in order to investigate the influence which a sealing agent has on a liquid crystal, the liquid crystal was immersed in the hardened sample, and the specific resistance was measured.
[0108]
The sealant prepared in Example 1 was cured by taking 0.5 g of the sealant in a 5 cc sample bottle and heating at 180 ° C. for 50 minutes. After 2 ml of the fluorinated liquid crystal composition 9 was added to the bottle containing the cured sample, the sample was aged at 100 ° C. for 20 hours. The results are shown in Table 1.
[0109]
[Table 1]

[0110]
(Examples 2 to 5), (Comparative Examples 1 and 2)
The liquid crystal display elements of Examples 2 to 5 of the present invention or Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 instead of the sealing agent prepared in Example 1 according to the formulation of Table 2, and Evaluation was performed in the same manner.
[0111]
In addition, as for the sealing agent hardening time of Comparative Examples 1 and 2, the temperature was the same and only the time was 4 hours. The results are shown in Table 1.
[0112]
[Table 2]

[0113]
Explanation of raw materials used in Table 2
Epoxy resin
Liquid epoxy resin A: bisphenol A type epoxy resin (RE-310S made by Nippon Kayaku)
Solid epoxy resin B: bisphenol A type epoxy resin (Epicoat 1001 made by oiled shell)
Hardener
Hardener A: Phenol novolac resin (PN-152: Binuclear content 40% Nippon Kayaku)
Curing agent B: Phenol novolac resin (PN-80: Binuclear content 12% Nippon Kayaku)
Curing agent C: 2,4-diamino-6- (2'-methylimidazolyl (1) ') ethyl-s-triazine isocyanuric acid adduct (2MAOK-PW, manufactured by Shikoku Chemicals)
Curing accelerator
Curing accelerator A: 2,4-diamino-6- (2'-methylimidazolyl (1) ') ethyl-s-triazine isocyanuric acid adduct (2MAOK-PW, manufactured by Shikoku Chemicals)
Amine Adduct (average particle size 3μm or less) Amicure MY-H (Ajinomoto)
2-ethyl 4-methylimidazole 2E4MZ (manufactured by Shikoku Chemicals)
solvent
Propylene glycol monoethyl ether acetate
Silane coupling agent
N-phenyl-γ-aminopropyltrimethoxysilane (KBM-573 manufactured by Shin-Etsu Chemical Co., Ltd.)
As is apparent from Table 1, the upper and lower glass substrates can be bonded together at room temperature during the production of the liquid crystal cell, and has excellent adhesive strength and moisture resistance reliability (-20 to 80 ° C.) that can withstand multiple surfaces, It can be seen that it is excellent in flexibility, can be cured in a short time, can form a predetermined gap, and does not cause contaminants to flow out of the liquid crystal from the cured sealant.
[0114]
FIG. 3 is an explanatory view showing the effect of the sealing agent according to the present invention in terms of the relationship between temperature and gelation time. The white circle is the sealing agent of Example 1 and the black circle is the sealing agent of Comparative Example 1.
[0115]
As shown in the figure, since the sealing agent of the present invention gels in a short time, the curing time is shorter than that of the comparative example, and a predetermined cell gap is formed.
[0116]
【The invention's effect】
As described above, the liquid crystal display element according to the present invention can perform bonding of the upper and lower substrates at room temperature when manufacturing the liquid crystal display element, and can withstand adhesive strength and moisture resistance (− 20 to 80 ° C), excellent flexibility, curing can be completed in a short time to form a predetermined gap, and contaminants are washed away from the cured liquid to the liquid crystal. This solves the problem of the prior art.
[0117]
Furthermore, it has sufficient resistance in energization tests under high temperature and high humidity, standing test at high temperature and low temperature, and heat cycle test, and sufficient reliability as a liquid crystal display element without causing cracking against thermal stress. Holds sex.
[0118]
In addition, since the liquid crystal composition is not deteriorated at the same time as sufficient adhesive strength is obtained, it is possible to provide a liquid crystal display element having excellent display characteristics without causing poor alignment of liquid crystal and lowering of electric resistance. it can.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an essential part for explaining the structure of an example of a liquid crystal display element according to the present invention.
FIG. 2 is a schematic explanatory diagram of a bonding process in the manufacturing process of the liquid crystal display element of the present invention.
FIG. 3 is an explanatory diagram showing the effect of the sealant according to the present invention in relation to temperature and gelation time.
[Explanation of symbols]
1 Liquid crystal control element
2 Pixel electrode
3 Substrate
4 Counter substrate
5 Color filter
6 Insulating film
7 Transparent electrode
8 Sealant
9 Liquid crystal composition.

Claims (10)

And one substrate having at least a liquid crystal control device and the pixel electrode, the other substrate having at least a color filter disposed opposite at a predetermined interval, after fixing the liquid crystal sealing agent interposed on the periphery, liquid crystal of the gap between the substrates In a liquid crystal display element sandwiched between
The liquid crystal sealing agent is (a) a liquid epoxy resin, (b) a curing agent comprising a novolac resin having a softening point of 75 ° C. or less by the ring and ball method, (c) a filler having a particle size of 10 μm or less, and (d) An amine adduct having an average particle diameter of 6 μm or less or 2,4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine isocyanuric acid adduct as an essential component as a curing accelerator, A liquid crystal display element, wherein the mixture of the component (b) and the component (b) is liquid or has a softening point of 50 ° C. or less as measured by the ring and ball method.   2. The liquid crystal display element according to claim 1, wherein the total chlorine content in the component (a) is 1500 ppm or less.   3. The liquid crystal display element according to claim 1, wherein the liquid epoxy resin (a) is a bisphenol A type liquid epoxy resin and / or a bisphenol F type liquid epoxy resin.   4. The liquid crystal display element according to claim 1, wherein the curing agent (b) comprises a novolac resin containing 20 to 80% by weight of a dinuclear body.   The liquid crystal display element according to claim 1, wherein the filler (c) has an average particle size of 2 μm or less.   6. The liquid crystal display element according to claim 1, wherein the content of the filler (c) is 5 to 30% by volume in the liquid crystal sealant.   The liquid crystal display element according to claim 1, wherein the filler of (c) is alumina and / or silica. The liquid crystal sealing agent, the liquid crystal display device according to any one of claims 1 to 7, characterized by containing a coupling agent. Wherein the coupling agent contained in the liquid crystal sealant, a liquid crystal display device according to any one of claims 1 to 7, characterized in that the aminosilane coupling agent. One substrate having at least a liquid crystal control element and a pixel electrode and the other substrate having at least a color filter are arranged to face each other at a predetermined interval, and a liquid crystal sealant is inserted around the periphery excluding the liquid crystal composition injection port at room temperature. A method for manufacturing a liquid crystal display element, wherein the liquid crystal composition is injected by injecting a liquid crystal composition from the liquid crystal injection port and sandwiching the liquid crystal in the gap between the two substrates after being superposed and fixed by heating. As a liquid crystal sealant, (a) a liquid epoxy resin, (b) a curing agent composed of a novolac resin having a softening point of 75 ° C. or less by the ring and ball method, (c) a filler having a particle size of 10 μm or less, and (d) curing the average particle diameter as a promoter is not more than the amine adduct or 2,4-diamino-6 (2'-methylimidazole (1 ')) ethyl -s- triazine isocyanuric acid adduct as an essential component 6 [mu] m, before A liquid crystal in which the mixture of the component (a) and the component (b) is liquid or has a softening point of 50 ° C. or less as measured by the ring and ball method, and the curing time at 160 to 180 ° C. is 50 minutes or less. A method for producing a liquid crystal display element, comprising using a sealant.

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