JP2004292672A - Carbon black dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon black-containing resin composition having high OD value of a coated film, excellent in developing characteristics and coated film surface characteristics. <P>SOLUTION: The carbon black dispersion comprises carbon black having 20-30 nm average primary particle diameter, ≤140 mL/100g DBP absorption amount and pH 2.5-4 and an organic compound having 1-100 mg KOH/g amine value and 5,000-12,000 weight-average molecular weight. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４２】
（式中、ＭはＣｕ、Ｔｉ、Ｎｉ、Ａｌ、Ｆｅ、Ｃｏ、Ｈ−Ｈを表し、Ｘ_１、Ｘ_２、Ｘ_３、Ｘ_４は独立に−Ｂｒ、−Ｃｌを表し、Ｙ_１、Ｙ_２、Ｙ_３、Ｙ_４は独立に−ＣＯＯＨ、−ＣＯＯＮａ、−ＣＯＯＫ、−ＳＯ_３Ｈ、−ＳＯ_３Ｎａ、−ＳＯ_３Ｋ、一般式［ＩＩ］で示される酸性アミン塩を表し、ｋ_１、ｋ_２、ｋ_３、ｋ_４、ｎ_１、ｎ_２、ｎ_３、ｎ_４は何れも０〜４の整数を表し、ｎ_１＋ｎ_２＋ｎ_３＋ｎ_４＝１〜４であり、好ましくはｋ_１＋ｋ_２＋ｋ_３＋ｋ_４＝０〜３である。）
一般式［ＩＩ］
【００４３】
【化２】

【００４４】
（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４は独立に水素原子、炭素数１〜４のアルキル基、炭素数１〜３のアルカノール基、炭素数１〜４のアルキル基で置換されたアルキルアカノール基を表す。）
【００４５】
水溶性フタロシアニン誘導体の合成は、例えば特開２０００−３１３８３７号公報に記載されるように、フタロシアニンを発煙硫酸や濃硫酸、クロロ硫酸などのスルホン化剤を用いてスルホン化するのが一般的である。カルボキシル基の導入は、フタロシアニン合成時の環化の原料として置換基を持ったものを使うことが行われている。合成した誘導体の官能基数は分布を持ち、精製分離をしない限りその置換基数は平均値として表される。好ましくは、酸性官能基の平均置換基数としては１以上２未満、更に好ましくは１〜１．９であり、２より多い置換基数を持つ場合には分散安定性を増加する効果が低い。
【００４６】
カーボンブラックへのフタロシアニン誘導体の吸着処理の方法は限定されず、顔料の分散に通常使用される分散機を用い、フタロシアニン誘導体の塩基性溶液中に顔料を添加して分散させる等、公知の方法を用いればよい。
特に好ましいフタロシアニン誘導体の具体例としては、
【００４７】
【化３】

【００４８】
【化４】

【００４９】
【化５】

【００５０】
等が挙げられる。もちろん、使用できるのはこれらの化合物のみに限定されるものではない。
これらの分散助剤を顔料の分散に使用することは従来より知られている。また、ブラックマトリックス形成用の感光性樹脂組成物で使用することも知られている（特開平１０−２０４，３２１号公報等）。しかし、ＢＭ用途で望まれる高特性実現のために、特定の一次物性の顔料及び特定の物性を有する高分子材料を用いる本発明の系において、これら特定の分散助剤が極めて好ましい性能を発揮することは容易には想到しえないことである。これら分散助剤の配合量は、カーボンブラック１００重量部に対して０．１〜５０重量部が好ましく、特に好ましくは１〜１０重量部である。
【００５１】
本発明の感光性樹脂組成物は後述するように、上述のカーボンブラック及び特定の有機化合物、並びに感光性の樹脂成分を含有するものであり、必要に応じて他の分散剤や分散助剤等を含有してもよい。
【００５２】
予め、上記の各成分を混合してカーボンブラック分散液を調製しておき、ここに樹脂成分を配合するのが望ましい。予めカーボンブラック分散液を調製して所望の分散度合いを達成しておくことにより、樹脂組成物中に均一にカーボンブラックを分散することが容易となる。
【００５３】
（分散液の調製方法）
カーボンブラック分散液を調製するための分散手段は特に限定されない。一般には、カーボンブラック、分散剤、必要に応じて分散助剤を分散媒に混合し、ガラスビーズ、ジルコニアビーズ等のメディアを加え、ペイントコンディショナー、ビーズミル、サンドミル、ボールミル、ディゾルバー、サンドグラインダー等により分散を行う。また、２本ロール、３本ロール、ニーダ―、ホモジナイザー系、ジェットミル、超音波等を用いて分散することもできる。これらの分散手段を複数組み合わせてもよい。この際、熱によりゲル化する恐れがある高分子化合物を用いた場合、必要に応じてハイドロキノン等の重合禁止剤を添加したり、冷却しても良い。
【００５４】
分散の程度は、カーボンブラックの分散粒径が１〜３００ｎｍ、好ましくは５０〜３００ｎｍ、さらに好ましくは８０〜２００ｎｍとなるように調整するのが望ましい。ここでの分散粒径は、例えば公知のレーザードップラー式の粒度測定器で求めた際の平均の粒子径である。
カーボンブラックは、超微細な粉体であること、さらに一次粒子が葡萄の房や鎖のように連なった、いわゆるストラクチャーを形成していることにより好ましい均一な分散を達成することは非常に困難であり、このことが、理論的に到達可能なＯＤ値を得られないことの一因となっていると推測されるが、本発明では上記の特定のカーボンブラックと特定の有機化合物との組み合わせにより、このような好ましい分散径を得ることが容易となり、このことが最終的な感光性樹脂組成物の性能の大幅な向上に寄与していることが考えられる。
【００５５】
また分散液の粘度は、３．０〜２００．０ｍＰａ・ｓ、好ましくは３．０〜１００．０ｍＰａ・ｓ、さらに好ましくは３．０〜３０．０ｍＰａ・ｓに調整するのが好ましい。
また、ここでの粘度は公知のコーンプレート型粘度形より求めた、分散液の液温２５℃での粘度である。
【００５６】
分散が不十分で分散粒径が上記の範囲より大きい場合には、粗大粒子と呼ばれる未分散カーボンブラックが残存し、フィルタリング工程での不良、さらにはＢＭの表面粗度、パターン形状に悪影響を及ぼすことがある。
一方、過分散と呼ばれる、過度に分散された状態になると、分散液粘度の増加や分散安定性に問題が生じ感光性樹脂組成物での塗布性や、現像特性に悪影響を及ぼすことがある。
なお、分散が不十分で粗大粒子がある場合でも、フィルタリングにてそれらを除去して上記の分散粒径の範囲に調整することができる。また、分散が十分な場合でも、系内の異物を除去する目的で、フィルタリングすることが望ましく、そのフィルタリングは通常の濾過器を用いて実施すればよい。
【００５７】
こうして本発明のカーボンブラック分散液を得ることができる。
カラーフィルターのブラックマトリックスを形成するには後述するように透明基板に塗布し露光して硬化させてブラックマトリックスとするのが一般的な工程であるため、以上説明したカーボンブラックの他、感光性の樹脂成分を含有させた感光性樹脂組成物として用いるのが一般的である。本発明の感光性樹脂組成物は、少なくとも、上述したカーボンブラックと、感光性の樹脂成分とを含有する。さらに、必要に応じてバインダー樹脂を含有していてもよく、一般には溶剤成分をも含有している。いわゆるブラックマトリックス形成用レジスト、黒色塗料組成物、感光性樹脂組成物と呼ばれカラーフィルターのブラックマトリックスの形成に用いられる各種のカーボンブラック含有組成物が相当する。
【００５８】
（光重合開始剤）
感光性樹脂組成物を露光により硬化させるため、一般に、光を吸収してラジカルを発生する光重合開始剤を含有させる。光重合開始剤としては、例えば、ベンジル；ベンゾインエーテル；ベンゾインイソブチルエーテル；ベンゾインプロピルエーテル；ベンゾインイソブチルエーテル；ベンゾフェノン；ベンゾイル安息香酸；４−ベンゾイル−４‘−メチルジフェニルサルファイド；ベンジルメチルケタール；２−ｎ−ブトキシエル−４−メチルアミノベンゾエート；２−クロロチオキサントン３，３’−ジメチル−４−メトキシベンゾフェノン、ベンゾイル安息香酸、ベンゾイル安息香酸メチル；ベンゾイル安息香酸のエステル化物、ベンジルジメチルケタール、メチルチオキサントン、エチルチオキサントン、イソプロピルチオキサントン、ジメチルチオキサントン、ジエチルチオキサントン、ジイソプロピルチオキサントン、ジメチルアミノメチルベンゾエート、ジメチルアミノ安息香酸イソアミルエステル、１−（４−ドデシルフェニル）−２−ヒドロキシ−２−メチルプロパン−１−オン、１−ヒドロキシシクロヘキシルフェニルケトン、２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オン、１−（４−イソプロピルフェニル）−２−ヒドロキシ−２−メチルプロパン−１−オン、メチルベンゾイルフォーメート、２−メチル−１−（４−メチルチオフェニル）−２−モルホリノプロパン−１−オン、２−ベンジル−２−ジメチルアミノ−１−（４−モルホリノフェニル）−ブタン−１−オン、２，２’−ビス（２−クロロフェニル）−４，４’，５，５’−テトラフェニルビスイミダゾール、２，２’−ビス（２−クロロフェニル）−４，４’，５，５’−テトラ−（４−メトキシフェニル）ビスイミダゾール等の、感光性樹脂組成物において公知の各種の光重合開始剤の１種又は２種以上を適宜選択して用いればよい。
これらの使用量は、感光性樹脂組成物の固形分を１００重量部としたとき０．５〜３０重量部、好ましくは１〜２５重量部加えることが望ましい。
【００５９】
（感光性の樹脂成分）
感光性の樹脂成分は、光重合開始剤の作用により硬化する感光性光架橋又は光重合可能な化合物であれば特に限定されず、例えば、モノマー、オリゴマー、プレポリマー等、限定されず用いられる。例えば、特開平１１−１４，８２２号公報等に記載されるような、エチレン性不飽和二重結合を少なくとも１つ以上有する光重合性化合物が代表的である。
【００６０】
使用されうるエチレン性不飽和二重結合を少なくとも１つ以上有する光重合性化合物としては、以下のような化合物が挙げられる。
【００６１】
光架橋または光重合可能なモノマー、オリゴマー、プレポリマーとして、エチルアクリレート、ブチルアクリレート、ヒドロキシエチルアクリレート、ヒドロキシエチルメタクリレート、エチレングリコールジメタアクリレート、ペンタエリスリトールトリアクリレート、ヒドロキシエチルメタクリレート、エチレングリコールジメタアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールトリメタアクリレート、ジペンタエリスリトールヘキサアクリレート、ジペンタエリスリトールヘキサメタクリレートのような１価又は多価アルコールのアクリル酸又はメタクリル酸のエステル類；多価アルコールと１塩基酸を縮合して得られるポリエステルプレポリマーに（メタ）アクリル酸を反応して得られるポリエステル（メタ）アクリレート；ポリオール基と２個のイソシアネート基を持つ化合物を反応させた後（メタ）アクリル酸を反応して得られるポリウレタン（メタ）アクリレート；ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ビスフェノールＳ型エポキシ樹脂、ノボラック型エポキシ樹脂、ポリカルボン酸グリシジルエステル、ポリオールポリグリシジルエステル、脂肪族又は脂環式エポキシ樹脂、アミンエポキシ樹脂、トリフェノールメタン型エポキシ樹脂、ジヒドロキシベンゼン型エポキシ樹脂などのエポキシ樹脂と（メタ）アクリル酸を反応させて得られるエポキシ（メタ）アクリレート等の通常の光重合性樹脂が挙げられる。
その他、メタノール、エタノール、プロパノール等の低級アルコール、（ポリ）エチレングリコール、（ポリ）プロピレングリコール、グリセリン、メチロールプロパン、ペンタエリスリトール、ジペンタエリスリトール等の多価アルコールと（メタ）アクリル酸を反応させて得られるエステル化合物、Ｎ−メチロールメラミン、Ｎ−メチロールベンゾグアナミン、（ポリ）Ｎ−メチロール（メタ）アクリルアミド等と（メタ）アクリル酸を反応させて得られるエステル化合物、無水マレイン酸と共重合可能なモノマー類とを重合して得られるポリマーとヒドロキシエチル（メタ）アクリル酸との反応物、アジドベンゾフェノン、アジドカルコン、アジドスチルベン、アジドベンザルシクロヘキサノン等のアジド化合物、メタノール、エタノール、プロパノール等の低級アルコール、（ポリ）エチレングリコール、（ポリ）プロピレングリコール、グリセリン、メチロールプロパン、ペンタエリスリトール、ジペンタエリスリトール等の多価アルコールとアジド安息香酸の縮合物、また、（メタ）アクリル酸、（メタ）アクリル酸エステル、、アクリルアミド、アクリロニトリル、酢酸ビニル、ビニルフェノール、ビニル安息香酸、スチレン、無水マレイン酸、ビニルブチラール、クロロプレン、塩化ビニル、ビニルピロリドン等のモノマー類を単独又は２種以上組み合わせて、ラジカル重合法もしくはイオン重合法等で重合させて得られる高分子化合物等が挙げられる。これらの使用量は、黒色顔料組成物中の高分子化合物１００重量部に対し３０〜２００重量部、好ましくは５０〜１５０重量部である。
配合割合は、カーボン１００重量部に対して１〜１００重量部、好ましくは、５〜５０重量部、更に好ましくは５〜３０重量部である。
【００６２】
これらのエチレン性不飽和二重結合を有するラジカル重合性モノマーは、単独又は２種以上の組み合わせで使用することが可能で、例えば、２−エチル、２−ブチルプロパンジオールジアクリレート、ペンタエリスリトールテトラアクリレート、ジペンタエリストールヘキサアクリレート、ジペンタエリストールペンタアクリレート、ポリオキシエチル化トリメチロールプロパントリアクリレート、トリス（２−アクリロイルオキシエチル）イソシアヌレート、１，４−ジイソプペニルベンゼン、１，４−ジヒドロキシベンゼンメタクリレート、デカメチレングリコールジアクリレート、エチレングリコールジアクリレート、トリエチレングリコールアクリレート、トリメチロールプロパントリアクリレート、またはジアリルフマレート等が挙げられる。特に、２−ブチルプロパンジオールジアクリレート、ペンタエリストールテトラアクリレート、ジペンタエリストールペンタアクリレート、またはポリオキシエチル化トリメチロールプロパントリアクリレートが好適である。
【００６３】
これらの光重合性化合物の中でも、その平均分子量が１０００以上の化合物は、光重合速度が極めて速く、感光性樹脂組成物中にこれらの化合物を含有せしめることが特に有用である。
特に、カルボキシル基等の酸性基とエチレン性不飽和二重結合をもつ光重合性化合物が好ましく使用される。これらの化合物は感光性樹脂中のエチレン性不飽和二重結合を持つ光重合性化合物の含有割合を上げ大気暴露下での重合速度を上げ、なおかつ水性現像を可能ならしめる点で極めて有用である。
【００６４】
そのようなカルボキシル基等の酸性基とエチレン性不飽和二重結合を併せ持つ光重合性化合物の具体例としては、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ノボラック型エポキシ樹脂、ポリカルボン酸グリシジルエステル、ポリオールグリシジルエステル、脂肪族又は脂環式エポキシ樹脂、アミンエポキシ樹脂、トリフェノールメタン型エポキシ樹脂、ジヒドロキシベンゼン型エポキシ樹脂などのエポキシ基と（メタ）アクリル酸を反応させて得られるヒドロキシ基に酸無水物を反応させてエポキシ（メタ）アクリレート−カルボン酸付加物無水マレイン酸と共重合可能な、エチレン、プロペン、イソブチレン、スチレン、ビニルフェノール、アクリル酸、アクリル酸エステル、アクリルアミド等のモノマーとの共重合体の無水マレイン酸部にヒドロキシエチルアクリレート等のアルコール性のヒドロキシ基を持つアクリレートやグリシジルメタクリレート等のエポキシ基をもつアクリレートを反応させハーフエステル化した化合物アクリル酸、アクリル酸エステルとヒドロキシエチルアクリレート等のアルコール性のヒドロキシ基を持つアクリレートの共重合体の−ＯＨ基にさらにアクリル酸を反応せしめた化合物等が挙げられる。
【００６５】
光重合性化合物の割合が、６０％以上となるように感光性樹脂組成物を作成するのが好ましい。
【００６６】
（バインダー樹脂）
バインダー樹脂は一般に、相溶性、被膜形成性、現像性、接着性等の光重合性層の改善のために、結合剤の役割を果たす有機高分子物質であり、例えば特開平１０−２５３，８２０号公報、特開平１１−１４，８２２号公報に記載されるものが挙げられる。
【００６７】
具体的には、例えば下記の化合物が挙げられる。
ポリエチレン、ポリプロピレン、ポリイソブチレン等のポリオレフィン系ポリマー；ポリブタジエン、ポリイソプレン等のジエン系ポリマー；ポリアセチレン系ポリマー、ポリフェニレン系ポリマー等の共役ポリエン構造を有するポリマー；ポリ塩化ビニル、ポリスチレン、酢酸ビニル、ポリビニルアルコール、ポリアクリル酸、ポリアクリル酸エステル、ポリアクリルアミド、ポリアクリロニトリル、ポリビニルフェノール等のビニルポリマー；ポリフェニレンエーテル、ポリオキシラン、ポリオキセタン、ポリテトラヒドロフラン、ポリエーテルケトン、ポリアセタール等のポリエーテル；ノボラック樹脂、レゾール樹脂等のフェノール樹脂；ポリエチレンテレフタレート、ポリフェノールフタレインテレフタレート、ポリカーボネート、アルキッド樹脂、不飽和ポリエステル樹脂等のポリエステル；ナイロン−６、ナイロン６６、水溶性ナイロン、ポリフェニレンアミド等のポリアミド；ゼラチン、カゼイン等のポリペプチド；ノボラックエポキシ樹脂、ビスフェノールエポキシ樹脂、ノボラックエポキシアクリレート及び酸無水物による変性樹脂等のエポキシ樹脂及びその変性物；その他、ポリウレタン、ポリイミド、メラミン樹脂、尿素樹脂、ポリイミダゾール、ポリオキサゾール、ポリピロール、ポリアニリン、ポリスルフィド、ポリスルホン、セルロース類等。
【００６８】
例えば、（メタ）アクリル酸と（メタ）アクリル酸アルキルエステル（例えば、メチル基、エチル基、ブチル基等）の共重合体、ポリ（メタ）アクリル酸、スチレンと無水マレイン酸等の不飽和二塩基酸無水物との共重合物が挙げられる。また、分子中にカルボン酸、ヒドロキシ基、アミノ基、カルボン酸アミド基、スルフォン酸アミド基等を含む高分子化合物も挙げられる。
【００６９】
これらの有機高分子物質の中では樹脂側鎖または主鎖にカルボキシル基あるいはフェノール性水酸基等を有する樹脂を含有する感光性樹脂組成物が、アルカリ現像可能なため、公害防止の観点から好ましい。特にカルボキシル基を有する樹脂、例えば、アクリル酸（共）重合体、スチレン／無水マレイン酸樹脂、ノボラックエポキシアクリレートの酸無水物変性樹脂等は高アルカリ現像性なので好ましい。
【００７０】
さらに、アクリル系樹脂は現像性に優れているので好ましく、様々なモノマーを選択して種々の共重合体を得ることが可能なため、性能および製造制御の観点から好ましい。より具体的にはカルボキシル基を含有するアクリル樹脂は、例えば、（メタ）アクリル酸、（無水）マレイン酸等、例えば特開平１０−２５３，８２０号公報に例示される各種のものが挙げられる。
【００７１】
これらのバインダー樹脂の添加量は、固形分総量の４０重量％以下、特に５〜３０重量％が好ましい。さらに好ましくは１５〜３０重量％の添加量である。この添加量が５重量％未満では基板とパターンの密着強度が低下し、３０重量％を超えると感光性の低下の原因となる。
耐熱性の向上の目的で、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ノボラック型エポキシ樹脂、ポリカルボン酸グリシジルエステル等のエポキシ化合物等を使用することもできる。エポキシ化合物とカルボン酸を持つ化合物との組み合わせにより、これらが反応し架橋して耐熱性が向上すると考えられる。
【００７２】
その他の耐熱性樹脂として例えばフッ素樹脂、シリコーン樹脂、ケイ素含有アクリル樹脂、ポリイミド、ポリイミドアミド、ポリジフェニルエーテル、ポリ（アルキレンイミン）、フェノール樹脂、キシレン樹脂などの耐熱性樹脂を、単独でまたは２種以上混合して用いることができる。
かかる耐熱性樹脂の添加により、また、本発明の液晶パネル用組成物から形成された皮膜に、たとえば２００〜３００℃程度の熱処理に施したばあいであっても、耐熱性の低下を防止できる。
【００７３】
（溶剤）
用いる溶剤には特に制限はなく、カーボンブラック分散液を得るため使用されるものと同じものを使用すればよい。また、感光性樹脂組成物調製時の作業性向上のための希釈溶剤として、エチルセロソルブ、エチルセロソルブアセテート、ブチルセロソルブ、ブチルセロソルブアセテート、エチルカルビトール、エチルカルビトールアセテート、ジグライム、シクロヘキサノン、プロピレングリコールモノメチルエーテルアセテート、乳酸エステル類等の有機溶剤を用いることもできる。
【００７４】
その他、必要に応じて基板との密着性を上げるためのシランカップリング剤やチタネートカップリング剤、膜の平滑性を上げるためのフッ素系、シリコン系、炭化水素系の界面活性剤及び紫外線吸収剤、酸化防止剤等の各種の添加剤を配合してもよい。
【００７５】
感光性樹脂組成物の具体例としては、いわゆるレジスト組成物としてカラーフィルター用途、ブラックマトリックス形成に用いられるものとして公知の各種のものが挙げられる。例えば、多官能アクリレートモノマーまたは多官能メタクリレートモノマーの何れかと、有機重合体結合剤と、ハロメチルオキサジアゾール系化合物及びハロメチル−ｓ−トリアジン系化合物から選択された少なくとも一種からなる光重合開始剤とを含有する組成物（特公平６−９５，２１１号公報）、感光性樹脂として、光を吸収してラジカルを発生する光重合開始剤と、光重合開始剤の作用により硬化するモノマーを含有し、さらに好ましくは相溶性、被膜形成性、現像性、接着性等の光重合性層の改善のために、結合剤としての有機高分子物質を含有させたもの、特に、アルカリ現像可能なため公害防止の観点から好ましいものとして有機高分子物質として樹脂側鎖または主鎖にカルボキシル基あるいはフェノール性水酸基等を有する樹脂を含有し、光重合開始剤の作用により硬化するモノマーとして光重合開始剤の発生するラジカルの作用によりラジカル重合するモノマー及び光重合開始剤から発生する酸の作用で付加縮合するモノマー等公知のものを含有するレジスト、なかでもカルボキシル基を含有するアクリル樹脂とアクリルモノマーとの組み合わせを含有するもの（特開平１０−２５３，８２０号公報）が挙げられる。
【００７６】
また、カーボンブラックの他にバインダー樹脂、エチレン系不飽和二重結合を有するモノマー及び光重合開始剤を含有する感光性樹脂組成物（特開平１１−１４，８２２号公報）、カーボンブラックと共に、光を吸収してラジカルを発生する光重合開始系と、当該ラジカルにより重合が誘起される付加重合性のエチレン性不飽和二重結合を少なくとも一個有する化合物（エチレン性化合物）とを含有し、さらに、必要に応じて有機高分子物質（バインダー樹脂）、分散剤などを含有する光重合性組成物（特開平１１−８０，５８４号公報）、ヒドロキシスチレンを主成分とする共重合体、架橋剤、光酸発生剤及びカーボンブラックを含有し、前記ヒドロキシスチレンを主成分とする共重合体が、ヒドロキシスチレン単位を５０モル％以上、さらにカルボン酸基を有するモノマー単位を５〜３０モル％を含む共重合体である黒色感光性組成物（特開平１１−２４，２６９号公報）、カーボンブラックの他に（Ａ）クレゾールを有するフェノール類とアルデヒド類とを縮合して得られるアルカリ可溶性樹脂及び（Ｂ）酸架橋性メチロール化メラミン樹脂、（Ｃ）光を吸収して酸を発生する、特定の構造の含ハロゲントリアジン化合物を含有するブラックマトリックス形成材料（特開平１１−１４３，０５６号公報）等が挙げられる。
【００７７】
ヒンダードフェノール系酸化防止剤を配合した感光性樹脂組成物（特開２００２−２２，９２５号公報）、感光性樹脂として、分子中にカルボキシル基を導入して水溶性を付与したものを使用することによってアルカリ水溶液での現像を可能にしたものとして、ノボラック型エポキシ樹脂、ビスフェノール型エポキシ樹脂、ビフェニル型エポキシ樹脂、脂環式エポキシ樹脂等の１分子中にエポキシ基を２個以上有するエポキシ樹脂と（メタ）アクリル酸等の不飽和一塩基酸とを反応する際に生成するヒドロキシル基と酸無水物とを反応させて得られるカルボキシル基含有エポキシ（メタ）アクリレート、無水マレイン酸と共重合可能なエチレン、プロピレン、イソブレチン、スチレン、ビニルフェノール、（メタ）アクリル酸、（メタ）アクリル酸エステル、アクリルアミド等のモノマーとの共重合体の無水マレイン酸部にヒドロキシエチル（メタ）アクリレート等のアルコール性のヒドロキシル基を持つ（メタ）アクリレートを反応させハーフエステル化した化合物、あるいはトリメチロールプロパンジ（メタ）アクリレートやペンタエリスリトールトリ（メタ）アクリレート等水酸基含有（メタ）アクリレートと酸無水物とのハーフエステル化物等が挙げられる（特開平８−３３７，７３６号公報）。
【００７８】
また近年、高耐熱性、溶剤溶解性、高透明性、高屈折率、低複屈折、高ガス透過性を有する高分子材料として知られるカルド型ポリマーが、ＢＭをはじめとするカラーフィルター形成に用いられる感光性樹脂成分として知られている。カルド型ポリマーとは環状の基が高分子主鎖に直接結合した構造を持つポリマーの総称であるが、主鎖にかさ高い置換基が存在することにより、（１）ポリマー主鎖の回転束縛、（２）主鎖および側鎖のコンフォメーション規制、（３）分子間パッキングの阻害、（４）側鎖の芳香族置換基導入による芳香族性の増加、などが発現され、さらに物性上の特徴として、高耐熱性、溶剤溶解性、高透明性、高屈折率、低複屈折などに加えて、より高いガス透過性を示すとされている。
【００７９】
このようなカルド型ポリマー、中でも下記の式（Ｉ）〜（Ｖ）で表されるような、フルオレン骨格を有するカルド型ポリマーが、カラーフィルター用の感光性樹脂として提案されており（特公平７−３５，４２６号公報、特開平７−４８４２４号公報、特開平９−２４１，３３９号公報、特開平９−２４１，３４０号公報、特開平９−３０４，９２９号公報、特開平９−３２５，４９４号公報、特開平９−３２８，５３４号公報等）、本発明の感光性樹脂組成物における感光性の樹脂成分としては、このようなカルド型ポリマーも特に好適に用いることができる。
【００８０】
式（Ｉ）：
【００８１】
【化６】

【００８２】
（式（Ｉ）中、Ｒは水素原子又はメチル基の何れかを示し、ｎは０〜２０の整数である。）
【００８３】
式（ＩＩ）：
【化７】

【００８４】
（式（ＩＩ）中、ｎは１以上の整数）
【００８５】
式（ＩＩＩ）：
【００８６】
【化８】

【００８７】
（式（ＩＩＩ）中、ｎは１以上の整数）
式（ＩＶ）：
【００８８】
【化９】

【００８９】
（式（ＩＶ）中、Ｒ１及びＲ２は水素原子、炭素数１〜５のアルキル基又はハロゲン原子を、ｎは１〜５の数を示す。Ａは４価の有機残基を、Ｘは１以上の数を示す。）
【００９０】
式（Ｖ）：
【００９１】
【化１０】

【００９２】
（式（Ｖ）中、ＲはＨ又は低級アルキル基、Ｒ’はＨ又はメチル基を示す。ｎ＝０〜２０の整数である。）
【００９３】
以上説明したカーボンブラック、感光性の樹脂成分等の他、カーボンブラック以外の顔料を配合してもよい。例えば、黒色低次酸窒化チタン、酸化チタン、硫酸バリウム、亜鉛華、硫酸鉛、黄色鉛、マンガン紫、コバルト紫、硫酸バリウム、ベンガラ、群青、酸化クロム、アンチモン白、鉄黒、鉛丹、硫化亜鉛、カドミウムイエロー、カドミウムレッド、亜鉛、炭酸マグネシウム等の金属酸化物、金属硫化物、硫酸塩、金属水酸化物、金属炭酸塩等のうち１種又は２種以上が挙げられる。しかしこの場合、カーボンブラック総量１００重量部に対して２０重量部以下、好ましくは１０重量部以下に抑えるのが、現像性の劣化とＯＤ値の低下を防止する点から望ましい。
【００９４】
感光性樹脂組成物の固形分量を１００重量部としたとき、カーボンブラックの割合は、５〜７０重量部、好ましくは１０〜６０重量部、有機顔料の割合は、４０重量部以下、好ましくは３０重量部以下、カーボン以外の無機顔料の割合は、６０重量部以下、好ましくは５０重量部以下で使用され、かつ総顔料割合は、２０〜８０重量部、好ましくは３０〜７５重量部で用いることができる。顔料総割合が２０重量部未満の場合、遮光性が充分でなく、８０重量部を超えると感度が低下や、塗布性が損なわれる等の不都合が生じる恐れがある。
【００９５】
以上の材料をディゾルバー型撹拌機、ターボ型撹拌機、二軸式撹拌機等の撹拌機を用いて混和して感光性樹脂組成物とするか、或いは２本ロールミル、３本ロールミル、サンドミル、ペイントシェーカー等の分散機を用いて混練して感光性樹脂組成物とするが、その際に用いられる前述した有機溶剤の好ましい量は通常、全固形分の５０〜２００重量％である。
【００９６】
本発明の感光性樹脂組成物は、導電性に優れ、さらには着色力および隠蔽力が大きく、たとえば液晶ディスプレーなどにおけるブラックマトリックスの形成などに特に好適に使用することができる。
【００９７】
耐熱性樹脂の配合する場合、その使用量は、本発明の感光性樹脂組成物に充分な耐熱性を付与するために、感光性樹脂組成物中での含有量が３重量％以上、なかんづく５重量％以上となるように調整することが好ましく、また組成物中に前述の光重合性モノマーとプレポリマーとが含まれているばあいには、両者の架橋反応を充分に進行させるために、感光性樹脂組成物中での含有量が５０重量％以下、なかんづく３０重量％以下となるように調整することが好ましい。
【００９８】
各成分の配合割合は、得られるＢＭに充分な導電性を付与するために、一般にはカーボンブラック１００重量部に対して前述した本発明で規定する特定の有機化合物１重量部以上、特に５重量部以上であることが好ましく、またカーボンブラックによる隠蔽力を充分に発現させる為に、カーボンブラック１００重量部に対して１００重量部以下、さらに好ましくは６０重量部以下である事が好ましい。分散媒の配合量は、感光性樹脂組成物の固形１００重量部に対して一般にはカーボンブラック及び前記特定の有機化合物並びに分散助剤等を差し引いたものである。
【００９９】
以上説明した感光性樹脂組成物を基板に塗布し、放射線を照射して硬化し、カラーフィルターのブラックマトリックスを形成する。
通常、以下のように作成される。ガラス基板等の基板上に、スピンコート法、ロールコート法、印刷法、バーコート法等の方法が使用される。膜厚が通常０．５〜５μｍになるように塗布し、プレベークを行い膜を作る。次に放射線（例えばＸ線、電子線、紫外線、可視光線、好ましくは紫外線）を全面に照射し、ポストベーク等の処理をして黒色硬化膜を得る。得られた黒色硬化膜は、遮光性、基板に対する密着性も高い。また、パターンを形成させる場合の画像露光は、光重合性層上にネガのマトリクスパターンマスクを介し、紫外または可視の光源を照射して行われる。アルカリ現像液としては、炭酸ナトリウム、炭酸カリウム、珪酸ナトリウム、珪酸カリウム、水酸化ナトリウム、水酸化カリウム等の無機アルカリ剤が使用される。
【０１００】
例えば、図２の（ａ）に示すように、ガラス基板等の透明基板（１）上に、感光性樹脂組成物をバーコート法、ロールコート法、スピンナー法、或いはカーテンコート法等の公知の手段により均一に塗布し、黒色樹脂層（２）を形成する。乾燥を必要とする場合は、７０〜１００℃程度の温度にて加熱してもよい。黒色樹脂層の膜厚は、好ましくは１．５μｍ以下、特に好ましくは１．０μｍ以下とすることで、次の工程で施す複数の色画素との重なり膜厚を小さくする。
【０１０１】
次に、図２の（ｂ）に示すように、マスク（３）を介して紫外光を照射するパターン露光を行い、感光性樹脂組成物を硬化させる。露光に使用する光源としては、高圧水銀灯、超高圧水銀灯が挙げられる。続いて、炭酸ナトリウム等のアルカリ金属塩、水酸化ナトリウム等のアルカリ金属水酸化物、テトラメチルアンモニウム等のハイドロオキサン有機塩基などのアルカリ水溶液を現像液として、未露光部分の黒色樹脂層を除去し、透明基板上に黒色樹脂層からなるブラックマトリックス（４）を形成する（図２の（ｃ））。
【０１０２】
次に、図２の（ｄ）に示すように、ブラックマトリックスとの重なりマージンを持たせた形態で複数の色画素（５）を設けて所望のカラーフィルターとする。また、他の方法として、図３の（ａ）に示すように予め複数色の色画素（５）が形成された透明基板（１）上に、感光性樹脂組成物をバーコート法、ロールコート法、スピンナー法、あるいはカーテンコート法等の公知の手段により塗布して黒色樹脂層（２）を形成する（図３の（ｂ））。
【０１０３】
必要に応じて乾燥した後、色画素をマスクとし、透明基板の裏面より紫外光を照射する背面露光を行い、感光性樹脂組成物を硬化させる（図３の（ｃ））。
【０１０４】
さらに、アルカリ現像及び水洗浄を行うことにより未露光部の黒色樹脂層を除去して基板上にブラックマトリックス（４）を形成し、乾燥等を経てカラーフィルターとする（図３の（ｄ））。
【０１０５】
本発明のカーボンブラック分散液や感光性樹脂組成物を用いてレジストパターンを形成する事により、優れた現像特性を得ることができる。これは、本発明のカーボンブラック含有樹脂組成物は、塗膜を透過する紫外光に対する感度が高いためと考えられる。このため、カーボンブラック含有量を増やすことができ、高いＯＤ値を得ることができ、これによりパターンの薄膜化が可能となる。
【０１０６】
また、本発明のカーボンブラック分散液や感光性樹脂組成物は抵抗調整が容易であり、ＢＭの表面抵抗値を１０^４〜１０^１４Ω・ｃｍ程度の広い範囲に調整することが可能であることから、低抵抗樹脂ＢＭにも好適に使用できる。つまり、高ＯＤ値で優れた現像性の低抵抗樹脂ＢＭを得ることができるのである。
【０１０７】
【実施例】
本発明を実施例によりさらに具体的に説明する。なお「部」及び「％」は特にことわりのない限り「重量部」及び「重量％」を表す。
【０１０８】
〔実施例１〕
（カーボンブラック分散液の調製）
市販のカーボンブラック（平均一次粒子径２４ｎｍ、ＤＢＰ吸油量１００ｍｌ／１００ｇ、ｐＨ３．０）を２０重量部、市販の高分子分散剤Ａ（ポリウレタン系高分子化合物、アミン価４５ｍｇＫＯＨ／ｇ、重量平均分子量８，０００、酸価０）を４．８重量部（固形分換算）、分散助剤として市販の銅フタロシアニン誘導体を０．６重量部、プロピレングリコールモノエチルエーテルアセテートを７４．６重量部に添加し、ビーズミルを用いて混合撹拌してカーボンブラック分散液を得た。
【０１０９】
〔液物性の測定〕
（１）分散安定性（粘度変化）
分散安定性は、カーボンブラック含有組成物を４０℃の温度を掛けて促進させ１ヶ月の粘度変化を測定した。測定結果を表−３に示す。粘度変化が５％以内を○、５％以上を×とする。
【０１１０】
（２）分散性（分散粒径）
得られたカーボンブラック分散液の平均分散粒径をコールターＮ４型粒子径測定器（ベックマン・コールター社製）を用いて測定した。希釈溶剤はプロピレングリコールモノメチルエーテルアセテートを使用した。測定結果を表−３に示す。
【０１１１】
（３）操作性（粘度）
また、このカーボンブラック分散液の２５℃の粘度をコーンプレート型粘度計（ＴＯＫＩＭＥＣ社製ＥＬＤ）を用いて測定した。測定結果を表−３に示す。
【０１１２】
（感光性樹脂組成物の調製）
プレポリマー（エポキシアクリレート）２０部及び光重合性モノマー（ジペンタエリスリトールヘキサアクリレート）１０部を、プロピレングリコールモノメチルエーテルアセテート７０重量部で希釈した後、光重合開始剤（２，４ジエチルチオキサントン）２部を添加し、希釈用樹脂液を調製した。
【０１１３】
前記のカーボンブラック分散液５０部、希釈用樹脂液３０部及びプロピレングリコールモノメチルエーテルアセテート２０部を、混合撹拌し、ブラックマトリックス形成用レジストとしての感光性樹脂組成物を得た。この樹脂組成物を用いて、以下の方法に従って物性の測定を行った。
【０１１４】
（ブラックマトリックスの形成）
上記の感光性樹脂組成物をスピンコーターにてガラス基板に塗布し、８０℃のホットプレート上でプレベークを行い厚さ約１μｍの塗膜を形成させた。次に、このサンプル塗膜を高圧水銀灯で像露光した後、温度２５℃、濃度０．０５％の水酸化カリウム溶液に浸漬現像し、さらに、２２０℃のホットプレート上で３０分間ポストベークを行い、ブラックマトリックスを形成した。
【０１１５】
〔ＢＭの物性の測定〕
（１）ＯＤ値
現像後のブラックマトリックスのパターン部のＯＤ値を、「マクベス（登録商標）濃度計」（ＴＲ−９２７ オルソマチックタイプ）を用いて測定した。結果を表−３に示す。
【０１１６】
（２）現像性
▲１▼パターン形状
ブラックマトリックスのパターンの形状を、光学顕微鏡で観察した。
評価は、パターンエッジのがたつきがなく最も良好であるものを○とし、がたつきがあるものを×とした。結果を表−３に示す。
【０１１７】
▲２▼密着性
現像後のブラックマトリックスのパターン部に、カッターナイフで１０ｍｍ×１０ｍｍ角内に、２ｍｍ×２ｍｍ角のキズを碁盤目状につけ、その傷にセロテープＬＰ−１８（登録商標）（ニチバン（株）製）を貼り付けた上から、５００ｇの重りを載せ、１０分間静置後、剥離する手法で密着性を評価した。
その評価は、塗膜の剥がれが５個所以内のものを○、剥れが１５個所以上のものを×とした。この評価は、同一基板内で２個所実施した。結果を表−３に示す。
【０１１８】
（３）表面抵抗値
ブラックマトリックスの表面抵抗値を、表面抵抗計（三菱化学株式会社製、「ハイレスターＵＰ」（ローレスタ？）、測定プローブＵＲＳ、印加電圧１０Ｖ）にて測定した。
表面抵抗が高すぎて測定上限を超えた（表示ＯＶＥＲ）サンプルについては、さらに印加電圧を１０００Ｖに変更し測定した。 結果を表−３に示す。
【０１１９】
〔実施例２〕
実施例１で用いたカーボンブラックを２０重量部、市販の高分子分散剤Ａ（（ポリウレタン系高分子化合物、アミン価４５ｍｇＫＯＨ／ｇ、重量平均分子量８，０００、酸価０）を２．４重量部（固形分換算）、更に他の市販の高分子分散剤Ｂ（ポリウレタン系高分子化合物、アミン価３２ｍｇＫＯＨ／ｇ、分子量１０，０００）を２重量部（固形分換算）、分散助剤として実施例１で用いたと同様の市販の銅フタロシアニン誘導体を０．８重量部、プロピレングリコールモノエチルエーテルアセテートを７４．８重量部に添加し、ビーズミルを用いて混合撹拌し、カーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２０】
実施例３
市販のカーボンブラックとして平均一次粒子径２１ｎｍ、ＤＢＰ吸油量６５ｍｌ／１００ｇ、ｐＨ３．０のものを２０重量部に替えた以外は、実施例１と同様にしてカーボンブラック分散液を得た。実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２１】
実施例４
平均一次粒子径２４ｎｍ、ＤＢＰ吸油量１００ｍｌ／１００ｇ、ｐＨ２．７のカーボンブラックを２０重量部、市販の高分子分散剤Ａ（ポリウレタン系高分子化合物、アミン価４５ｍｇＫＯＨ／ｇ、重量平均分子量８，０００、酸価０）を４．８重量部（固形分換算）、分散助剤として市販の銅フタロシアニン誘導体を０．６重量部、プロピレングリコールモノエチルエーテルアセテート７４．６重量部に添加し、ビーズミルを用いて混合撹拌し、カーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２２】
実施例５
平均一次粒子径２４ｎｍ、ＤＢＰ吸油量１００ｍｌ／１００ｇ、ｐＨ３．５のカーボンブラックを２０重量部に変えた以外は、実施例４と同様に行った。結果を表−３に示す。
【０１２３】
比較例１
市販のカーボンブラック（平均一次粒子径５５ｎｍ、ＤＢＰ吸油量９３ｍｌ／１００ｇ、ｐＨ３．０）を２０重量部、市販の高分子分散剤Ａ（ポリウレタン系高分子化合物、アミン価４５ｍｇＫＯＨ／ｇ、分子量８，０００、酸価０）を４．８重量部（固形分換算）、分散助剤として市販の銅フタロシアニン誘導体を０．６重量部、プロピレングリコールモノエチルエーテルアセテートを７４．６重量部に添加し、ビーズミルを用いて混合撹拌し、カーボンブラック分散液を得た。
【０１２４】
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２５】
比較例２
平均一次粒子径２４ｎｍ、ＤＢＰ吸油量１００ｍｌ／１００ｇ、ｐＨ３．０のカーボンブラックを２０重量部、分散剤として市販の高分子分散剤Ｃ（ポリウレタン系高分子化合物、アミン価３７．５ｍｇＫＯＨ／ｇ、重量平均分子量１５０００）を４．８重量部（固形分換算）、分散助剤として市販の銅フタロシアニン誘導体を０．６重量部、分散媒としてプロピレングリコールモノエチルエーテルアセテートを７４．６重量部に添加し、ビーズミルを用いて２５℃で混合撹拌し、カーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２６】
比較例３
平均一次粒子径２４ｎｍ、ＤＢＰ吸油量１００ｍｌ／１００ｇ、ｐＨ３．０のカーボンブラックを２０重量部、分散剤として市販の高分子分散剤Ｄ（ポリウレタン系高分子化合物、アミン価３７ｍｇＫＯＨ／ｇ、重量平均分子量２００００）を４．８重量部（固形分換算）、分散助剤として市販の銅フタロシアニン誘導体を０．６重量部、分散媒としてプロピレングリコールモノエチルエーテルアセテートを７４．６重量部に添加し、ビーズミルを用いて２５℃で混合撹拌し、カーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２７】
比較例４
カーボンブラックとして平均一次粒子径２４ｎｍ ＤＢＰ吸油量９８ｍｌ／１００ｇ、ｐＨ７．７のものを用いた以外は実施例１と同様に行い、カーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２８】
比較例５
カーボンブラックとして平均一次粒子径５０ｎｍＤＢＰ吸油量１７５ｍｌ／１００ｇ、ｐＨ７のものを用いた以外は実施例１と同様に行いカーボンブラック分散液を得た。
実施例１同様の方法で液物性の測定を行った。結果を表−３に示す。さらに実施例１と同様の方法で（感光性樹脂組成物の調製）、（ブラックマトリックスの形成）及び（ＢＭの物性の測定）を行った。結果を表−３に示す。
【０１２９】
実施例１〜５及び比較例１〜５で使用したカーボンブラック及び高分子分散剤の物性（各々、一次粒子径、ＤＢＰ吸油量及びｐＨ、高分子の種類、重量平均分子量、アミン価及び酸価）並びに分散助剤の種類について、表−１に示す。使用したカーボンブラックの物性及び高分子分散剤の物性間の関係を表−２に示す。用いた高分子分散剤のアミン価と重量平均分子量の関係を表−２に示す。なお各表中、「分子量」は「重量平均分子量」を表し、以下の測定方法で求めたものである。
試料調整：試料１５ｍｇに３ｍｌのＧＰＣ測定用移動相を加えて溶解し、０．４５μｍの親水性ＰＴＦＥ（Ｍｉｌｌｅｘ−ＬＨ：日本ミリポア社製）で濾過する。
装置：５１５高圧ポンプ、７１７ｐｌｕｓ自動注入装置（日本ウォーターズ）
ＲＩ−１０１（昭和電工（株）製）
カラム：ＰＬｇｅｌ ５ ＭＩＸＥＤ−Ｄ （６００×７．５ｍｍ）（Ｐｏｌｙｍｅｒ Ｌａｂｏｒａｔｏｒｉｅｓ社製）
カラム温度：常温
移動相：ＴＨＦ ０．０３％ ＢＨＴ添加
流量：１．０ｍｌ／ｍｉｎ
検出：ＲＩ
注入量：５０μＬ
【０１３０】
【表１】

【０１３１】
【表２】

【０１３２】
【表３】

【０１３３】
以上の実施例及び比較例から明らかなように、本発明のカーボンブラック分散液、本発明の感光性樹脂樹脂組成物は操作性に優れ、これらを用いることによって現像性、ＯＤ値共に優れたブラックマトリックスを形成できることがわかる。
【０１３４】
【発明の効果】
本発明により、操作性に優れたカーボンブラック分散液及びカーボンブラック含有樹脂組成物を提供でき、これらを用いることによって現像性、ＯＤ値共に優れたブラックマトリックスを形成できる。
【図面の簡単な説明】
【図１】カラーフィルターの製造工程を示す説明図
【図２】カラーフィルターの製造工程を示す説明図
【符号の説明】
１ 透明基板
２ 黒色樹脂層
３ マスク
４ ブラックマトリックス
５ 色画素[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a curable composition and a carbon black dispersion suitably used for forming a black matrix of a color filter and the like.
[0002]
[Prior art]
Conventionally, chromium has been used as a black matrix for color filters, but there is a concern that chromium may affect the environment. On the other hand, a light-shielding material such as carbon black is blended with a polymer material such as a photosensitive resin to form a black photosensitive resin composition, which is applied to a substrate and cured to form a black for a color filter. A so-called resin BM that forms a matrix has been conventionally proposed (Non-Patent Document 1, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, etc.).
[0003]
In particular, in the IPS (In-Plane-Switching) system in which the electric field in the panel is in the horizontal axis direction, since the BM material also needs to be insulative, it is necessary to form an insulative black matrix by using insulative carbon black. (Patent Document 5, Patent Document 6, Patent Document 7, etc.).
[0004]
In addition, in order to obtain a composition having improved photosensitivity and high precision, and also improved light-shielding properties represented by OD values, and further having good dispersibility and improved coatability during coating film formation. Various attempts have been made. For example, using a light-shielding material having a plurality of particle sizes (Patent Documents 8 and 9), using a combination of a plurality of types of light-shielding materials (Patent Documents 10, 11, and 12), and a specific dispersion It has been proposed to use an agent (Patent Documents 13 and 14) and to select a specific light-shielding material (Patent Document 15).
[0005]
[Non-Patent Document 1] "Pigment dispersion technology and surface treatment technology / evaluation" (Technical Information Association, 2001.12.15 edition)
[Patent Document 1] Japanese Patent Application Laid-Open No. 4-63,870
[Patent Document 2] JP-A-5-311,109
[Patent Document 3] JP-A-6-35,188
[Patent Document 4] JP-A-9-26,571
[Patent Document 5] JP-A-2001-106,938
[Patent Document 6] JP-A-2001-152,048
[Patent Document 7] Japanese Patent Application Laid-Open No. 9-95,625
[Patent Document 8] JP-A-11-80,584
[Patent Document 9] JP-A-9-279082
[Patent Document 10] JP-A-8-73,800
[Patent Document 11] JP-A-4-63,870
[Patent Document 12] JP-A-10-60169
[Patent Document 13] JP-A-10-204,321
[Patent Document 14] JP-A-10-253,820
[Patent Document 15] JP-A-6-35,188
[0006]
[Problems to be solved by the invention]
However, it has been difficult to obtain developability and OD value at the same time by any of these conventional means. That is, in the case of the resin BM, in order to obtain an OD value equivalent to that of the chromium-based BM using chromium, a film thickness that is one order of magnitude or more is required. In particular, recently, with the increase in the luminance of the panel, a higher light-shielding property, that is, an OD value is required for the BM. However, since the resin BM is irradiated with light such as ultraviolet light to cure the film, it is difficult to solve the problem that the resin BM has a high light-shielding property and is sufficiently cured by the irradiation light in the inherently opposite directions. In addition, there remains a problem with the demand for operability and high definition in the process.
[0007]
[Means for Solving the Problems]
In view of the above-mentioned problems, the present inventors have conducted intensive studies. As a result, they found that these problems can be solved by using a specific carbon black as a light-shielding material and dispersing using a specific compound, and reached the present invention. That is, the present invention
(1) Carbon black having an average primary particle diameter of 20 to 30 nm, a DBP absorption of 140 ml / 100 g or less, and a pH of 2.5 to 4, and an organic compound having an amine value of 1 to 100 mgKOH / g and a weight average molecular weight of 5000 to 12,000. Containing carbon black dispersion,
(2) The carbon black dispersion according to the above (1), which is used for forming a black matrix.
(3) Carbon black having an average primary particle diameter of 20 to 30 nm, a DBP absorption of 140 ml / 100 g or less, and a pH of 2.5 to 4, and an organic compound having an amine value of 1 to 100 mgKOH / g and a weight average molecular weight of 5000 to 12,000. , A photosensitive resin composition containing a photosensitive resin component,
[0008]
(4) a photosensitive resin composition obtained by blending a photosensitive resin component with the carbon black dispersion described in (1) or (2) above;
(5) The photosensitive resin composition according to the above (3) or (4), which is used for forming a black matrix.
(6) a black matrix obtained by applying and curing the photosensitive resin composition according to (5) above on a substrate,
(7) A color filter comprising the black matrix according to (6).
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The carbon black dispersion of the present invention is characterized by containing carbon black having specific physical properties and an organic compound having specific physical properties. It is thought that some chemical behavior occurs between the carbon black and the organic compound, but since there is no strong chemical bond between the two, this specific carbon black has essentially It is considered that the coloring power and the hiding power are sufficiently exhibited without losing them.
In addition, since these are relatively uniformly and finely dispersed, the viscosity of the obtained photosensitive resin composition does not extremely increase, and it is suitable for a film formed using the photosensitive resin composition. It is presumed that excellent physical properties such as high mechanical strength are imparted and excellent adhesion to the substrate are exhibited.
[0010]
(Carbon black)
In the present invention, the following are used as carbon black.
The carbon black used in the present invention has a primary particle diameter of 20 to 30 nm, preferably 20 to 25 nm. If it is less than 20 nm, sufficient dispersibility and dispersion stability cannot be obtained. If it exceeds 30 nm, the pattern shape of the BM deteriorates, for example, the surface of the obtained black matrix (hereinafter also referred to as BM) becomes jagged. Further, it is difficult to obtain a black matrix having a high OD value, which is not preferable. Here, the primary particle diameter is determined by electron microscopy, that is, taking an electron micrograph at a magnification of several tens of thousands, measuring several thousand particles, and calculating the average value.
[0011]
The carbon black used in the present invention has a DBP oil absorption of 140 ml / 100 g or less. Particularly preferably, it is 120 ml / 100 g or less. When the DBP oil absorption exceeds 140 ml / 100 g, the blackness of the carbon black itself is reduced, and not only is the density of the photosensitive resin composition prepared but not sufficiently high when the BM is formed, but also the carbon black dispersion or the light The viscosity of the water-soluble resin composition may also increase, and a coating film having good smoothness may not be obtained. Here, the DBP oil absorption can be measured according to JIS K6221 (1982).
[0012]
The carbon black used in the present invention has a pH of 2.5 to 4. Preferably it is 2.6-3.8. If it is less than 2.5, the resistance value is 10 ⁶ Ω · cm or more, and the insulating property is too high as a substitute for chromium. On the other hand, when it exceeds 4, the dispersibility decreases.
The pH was measured by adding 20 g of carbon black to distilled water (pH 7.0), boiling for 5 minutes, cooling to room temperature, and measuring the pH of the muddy carbon black with a glass electrode pH meter. Can be
[0013]
The ash content of the carbon black is not particularly limited, but those having an ash content of 1.0% by weight or less, particularly 0.5% by weight or less are particularly preferred because of their excellent dispersibility. The measurement of the ash content can be calculated from the amount of ash remaining when the carbon black is calcined in air at 750 ° C. for 5 to 6 hours.
[0014]
The specific surface area of the carbon black is not particularly limited, but the value measured by the BET method is usually 20 to 1500 m. ² / G, especially 50-1200m ² / G is preferred.
As carbon black, carbon black provided with insulation by means such as resin coating as described in Patent Document 5, Patent Document 6, Patent Document 7, etc. may be used. With a resistance value of 10 ⁴ -10 ⁶ When used for a so-called low-resistance resin BM having a relatively low resistance of Ω · cm and a high dielectric constant, a carbon black having normal conductivity is sufficient instead of these insulating carbon blacks. Of course, a plurality of types of carbon black may be used.
[0015]
(Organic compound)
The present invention is characterized by containing the specific carbon black described above and the specific organic compound described below. That is, it is an organic compound having an amine value of 1 to 100 mgKOH / g and a weight average molecular weight of 5,000 to 12,000.
Such an organic compound can be selected from substances generally known as a polymer dispersant, and can also be newly synthesized and used.
[0016]
(1) Amine value
The amine value of the organic compound used in the present invention is 1 to 100 mgKOH / g, preferably 30 to 65 mgKOH / g. When the amine value is less than 1 mgKOH / g, the dispersion stability is not sufficient. When the amine value exceeds 100 mgKOH / g, the developability and the resolution deteriorate.
[0017]
The amine value is measured by neutralizing and titrating a basic functional group with an acid and expressing the result in terms of mg of KOH in correspondence with the acid value. A typical method for measuring the amine value is the method described in DIN 16945.
[0018]
(2) Weight average molecular weight
The weight average molecular weight of the organic compound used in the present invention is 5,000 to 12,000 in terms of weight average in terms of polystyrene. Particularly preferably, it is 7,000 to 11,000, more preferably 7,500 to 10,500. If the weight average molecular weight is less than 5,000, dispersion is poor, adhesion to a substrate (glass or the like) is reduced, and developability and resolution are reduced. When the weight average molecular weight exceeds 100,000, developability and resolution deteriorate.
That is, when the BM is larger than the range defined in the present invention, the stability of the liquid tends to be low, and the obtained BM pattern shape is x. The development time is also slow. Possibly, it is considered that the miscibility with the photosensitive resin is poor, that the irradiation energy is prevented from reaching the photosensitive resin, or that the adhesion to the substrate (glass plate) is too good, and that some other obstacles are caused. You.
[0019]
The relationship between the amine value and the weight average molecular weight is as follows: {amine value [mgKOH / g] / weight average molecular weight} × 10 ³ Is the value of 1 Is preferred, more preferably 3 That is all. The organic compound in this range is particularly excellent in the liquid properties such as the dispersibility, stability, and coatability of the resulting carbon black dispersion and photosensitive resin composition, and at the same time, the photosensitive represented by the exposure time during BM production. It is excellent in both developability and OD value in terms of developability and the pattern shape of the obtained BM.
[0020]
(3) Acid value
The acid value of the organic compound used in the present invention is not particularly limited. However, preferably, the acid number is
100 [mgKOH / g] or less, more preferably 50 [mgKOH / g] or less, especially preferably an acid value of zero. The measurement of the acid value is typically performed by the method described in DIN 53402.
[0021]
Regarding the relationship between the particle size of carbon black and the amine value of the organic compound, the value of {primary particle size (nm) of carbon black / amine value of the organic compound [mgKOH / g]} is preferably 3 or less, particularly preferably 2 or less. , More preferably 1.5 or less.
[0022]
The ratio of the DBP absorption amount of carbon black to the amine value of the organic compound is such that the DBP absorption amount of carbon black / the amine value of the organic compound = 0.5 to 10, preferably 1.0 to 5.0, and more preferably 2. 0 to 4.0.
The ratio of the specific surface area of carbon black to the weight average molecular weight of the organic compound is such that the specific surface area of carbon black / the weight average molecular weight of the organic compound is 0.001 to 0.050, preferably 0.005 to 0.040, and more preferably 0.005 to 0.040. 0.008 to 0.020.
[0023]
The ratio of the DBP absorption of carbon black to the weight average molecular weight of the organic compound is as follows: DBP absorption of carbon black / weight average molecular weight of organic compound = 0.001 to 0.050, preferably 0.005 to 0.040, and Preferably it is 0.008-0.020.
When these are in this range, an adsorption layer of an appropriate thickness is firmly formed around the carbon black, thereby obtaining a fine and stable dispersion state with high dispersibility and the light shielding property of the carbon black. It is conceivable that they are expressed without disturbing the expression. It is considered that when the amine value is within this range with respect to the surface of the carbon black, the electrostatic properties of the adsorption layer are good.
[0024]
As such an organic compound that can be used in the present invention, among those generally used as a polymer dispersant, particularly, those having a basic functional group can be selected. As the thermoplastic resin, any of a thermosetting resin can be used, and as the thermosetting resin, urethane-based, acrylic-based, polyimide-based, alkyd-based, epoxy-based, unsaturated polyester-based, melamine-based, phenol-based, etc. Examples of the thermoplastic resin include an acrylic resin, a vinyl chloride resin, a vinyl chloride vinyl acetate copolymer, a urethane resin, a polyamide resin, and a polycarbonate resin.
[0025]
Among these, a polyurethane polymer dispersant is particularly preferable. Here, a polyurethane-based polymer is a polymer compound having a plurality of urethane bonds in its main chain, and a so-called urethane resin corresponds thereto, and a water-soluble or water-soluble polymer obtained by reacting a diisocyanate compound with a diol compound. Dispersible urethane resins are known and can be used.
[0026]
Examples of the diisocyanate compound include alicyclic compounds such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate. Aromatic diisocyanate compounds such as diisocyanate compounds, xylylene diisocyanate, and tetramethyl xylene diisocyanate; aromatic diisocyanate compounds such as toluylene diisocyanate and phenylmethane diisocyanate; Is mentioned.
[0027]
Examples of the diol compound include a diol compound obtained by (co) polymerizing an alkylene oxide such as ethylene oxide or propylene oxide or a heterocyclic ether such as tetrahydrofuran. Specific examples of such diol compounds include polyether diols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol, polyethylene adipate, polybutylene adipate, polyneopentyl adipate, and poly-3-methyl. Examples thereof include polyester diols such as pentyl adipate, polyethylene / butylene adipate, and polyneopentyl / hexyl adipate; polylactone diols such as polycaprolactone diol; and polycarbonate diols. Among these, one or more of polyether, polyester and polycarbonate are preferred.
[0028]
In addition to the above, diol compounds having an acidic group such as a carboxylic acid group and a sulfonic acid group can also be used, and specific examples thereof include dimethylolacetic acid, dimethylolpropionic acid, and dimethylolbutyric acid. Of these, dimethylolpropionic acid is preferred.
These diol compounds may be used in combination of two or more.
[0029]
In synthesizing the polyurethane polymer, a low molecular weight polyhydroxy compound may be added. Examples of the low molecular weight polyhydroxy compound include glycol, alkylene oxide low molar adducts, glycerin, trimethylolethane, trimethylolpropane and other trihydric alcohols used as raw materials for polyester diols, and alkylene oxide low molar adducts thereof. No. The urethane prepolymer thus obtained can be water-extended or chain-extended with di (tri) amine after or while neutralizing an acid group derived from dimethylolalkanoic acid. Examples of the polyamine used for chain extension include hexamethylenediamine, isophoronediamine, hydrazine, piperazine, and the like, and two or more of these may be used in combination.
[0030]
The form of the polyurethane polymer is not particularly limited. For example, emulsion types such as a self-emulsifying emulsion and a self-stabilizing type may be mentioned. In particular, among the above-mentioned compounds, diols having an acidic group such as a carboxylic acid group and a sulfonic acid group are used, or a low-molecular weight polyhydroxy compound is added, or a urethane resin having an acidic group introduced therein, particularly one having a carboxy group Is mentioned.
[0031]
These resins may be further neutralized, and examples of the base used for neutralization include alkylamines such as butylamine and triethylamine, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and morpholine. , Ammonia, and inorganic bases such as sodium hydroxide.
The polymer having an amide bond and / or a urethane bond is preferably a polyether-based polyurethane resin, a polyester-based polyurethane resin, or a polycarbonate-based polyurethane obtained by using a polyether-based, polyester-based, or polycarbonate-based diol as a diol compound. Resins.
[0032]
As described above, the organic compound that can be used in the present invention is most preferably a polyurethane polymer compound. As described above, the polyurethane-based polymer compound refers to a polymer compound having a plurality of urethane bonds in the main chain, and the weight-average molecular weight and the amine value fall within the ranges specified in the present invention. The structure and the production method are not particularly limited as long as the compound contains (i) a polyisocyanate, (ii) a compound having a hydroxyl group, (iii) Zerewitinoff active hydrogen and at least one nitrogen atom. A dispersant containing a polyurethane polymer compound obtained by reacting a compound having a basic group and (if necessary) (iv) a compound having an amine nitrogen atom is preferred. Particularly, an aromatic isocyanurate-based isocyanate is preferably used as the isocyanate and reacted with a polyol. For example, USP. 4,762,752, USP. 4,647,647, USP. 4,795,796, USP. 4,942,213, USP. 5,399,294, USP. 5, 425, 900 and WO 97/26, 984 are preferably used. The type and amount of each reaction component may be appropriately selected, and may be adjusted so that the weight average molecular weight and the amine value fall within the ranges specified in the present invention.
[0033]
Among the polyurethane-based polymer compounds described in these documents, it is desirable to use, as the above (iii), a urethane-based polymer material into which a nitrogen-containing heterocyclic ring is introduced by using a compound having a nitrogen-containing heterocyclic ring. Such a urethane-based polymer material having a nitrogen-containing heterocyclic ring is conventionally known as a pigment dispersant, as described in the above-mentioned known literature. However, in the case of BM application, not only good dispersibility but also interaction with not only the pigment but also the photosensitive resin may affect the developability of the obtained resist and optical characteristics such as the OD value of the formed BM. It must have the desired effect and reach the required high level. Selection of a suitable combination from this point has been extremely difficult. The specific combination of the present invention can provide an excellent BM-forming composition that can satisfy all of these properties.
[0034]
Although the amount of the specific organic compound described above is not limited, it is usually preferably at least 1 part by weight, particularly preferably at least 5 parts by weight, based on 100 parts by weight of carbon black, and sufficient conductivity for the obtained BM. 100 parts by weight or less, more preferably 60 parts by weight or less, further preferably 50 parts by weight or less, and most preferably 30 parts by weight or less, based on 100 parts by weight of carbon black in order to impart properties and sufficiently exhibit the hiding power of carbon black. It is appropriate to use not more than parts by weight. The specific organic compounds described above may be used alone or in combination of two or more.
[0035]
<Carbon black dispersion>
The carbon black and the specific organic compound described above are contained in a dispersion medium to form a carbon black dispersion.
[0036]
(Dispersion medium)
The dispersion medium of the carbon black dispersion of the present invention is not particularly limited, and may be appropriately selected from those usually used for carbon black dispersion. For example, benzene solvents such as benzene, toluene, xylene, etc., cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetates such as methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene Propylene glycol monoalkyl ether acetates such as glycol monoethyl ether acetate propylene glycol monobutyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, propionates such as ethyl ethoxypropionate, methyl lactate, Lactic acid esters such as ethyl lactate and butyl lactate, diethylene glycol monomethyl Ethers, diethylene glycols such as diethylene glycol monoethyl ether, etc., methyl acetate, ethyl acetate, butyl acetate, acetates such as aluminum acetate, dimethyl ether, diethyl ether, ethers such as tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, methyl butyl ketone, cyclohexanone Ketones, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, methoxypropyl acetate, cellosolve acetate solvents such as 2-methoxyethyl acetate, 3-ethoxyethyl propionate, propylene glycol monomethyl ether propionate, etc. Organic solvents such as hydrocarbon compounds having an ether bond and an ester bond, water, and the like. These may be used alone or as a mixture of two or more. The obtained solution and / or dispersion liquid is used after being subjected to redispersion treatment or filtration as necessary to remove impurities.
[0037]
Although the amount of the dispersion medium is not limited, the concentration of carbon black in the dispersion liquid is generally 5 to 50% by weight, preferably in view of easy mixing with the resin composition described later and dispersion stability. Is adjusted to be 10 to 30% by weight.
[0038]
(Dispersion aid)
If necessary, a compound such as a known dispersing aid may be added. These compounds have the function of mediating between carbon black and the dispersant, and are considered to have a function of electrically and chemically adsorbing the carbon black surface and the dispersant to improve the dispersion stability. ing.
[0039]
Examples of such a dispersing agent include a polycarboxylic acid type polymer activator, an anionic activator such as a polysulfonic acid type polymer activator, and a nonionic activator such as polyoxyethylene and polyoxylen broloc polymer. Although preferred, anthraquinone, phthalocyanine, metal phthalocyanine, quinacridone, azochelate, azo, isoindolinone, pyranthrone, indanthrone, anthrapyrimidine, dibromoanthanthrone, flavanthrone are preferred. A pigment derivative having an organic pigment such as a perylene-based, perylene-based, perinone-based, quinophthalone-based, thioindigo-based, or dioxazine-based as a base, and having introduced a substituent such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a carbonamide group, or a sulfonamide group No. Of these, phthalocyanine-based and metal phthalocyanine sulfonamide compounds are particularly effective.
[0040]
(Phthalocyanine derivative)
Among these compounds known as dispersion aids, it is particularly preferable to use phthalocyanine derivatives. Examples of the phthalocyanine derivative include a phthalocyanine compound represented by the following general formula [I].
General formula [I]
[0041]
Embedded image

[0042]
(Where M represents Cu, Ti, Ni, Al, Fe, Co, HH, X ₁ , X ₂ , X ₃ , X ₄ Independently represents -Br or -Cl; ₁ , Y ₂ , Y ₃ , Y ₄ Is independently -COOH, -COONa, -COOK, -SO ₃ H, -SO ₃ Na, -SO ₃ K represents an acidic amine salt represented by the general formula [II]; ₁ , K ₂ , K ₃ , K ₄ , N ₁ , N ₂ , N ₃ , N ₄ Each represents an integer of 0 to 4; ₁ + N ₂ + N ₃ + N ₄ = 1 to 4, preferably k ₁ + K ₂ + K ₃ + K ₄ = 0 to 3. )
General formula [II]
[0043]
Embedded image

[0044]
(Where R ₁ , R ₂ , R ₃ , R ₄ Independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkanol group having 1 to 3 carbon atoms, or an alkyl akanol group substituted with an alkyl group having 1 to 4 carbon atoms. )
[0045]
The synthesis of a water-soluble phthalocyanine derivative is generally carried out by sulfonating phthalocyanine using a sulfonating agent such as fuming sulfuric acid, concentrated sulfuric acid, or chlorosulfuric acid, as described in, for example, JP-A-2000-313837. . The introduction of a carboxyl group has been carried out by using a compound having a substituent as a starting material for cyclization during the synthesis of phthalocyanine. The number of functional groups of the synthesized derivative has a distribution, and the number of substituents is expressed as an average value unless purification and separation are performed. Preferably, the average number of substituents of the acidic functional group is 1 or more and less than 2, more preferably 1 to 1.9. When the number of substituents is more than 2, the effect of increasing the dispersion stability is low.
[0046]
The method of the adsorption treatment of the phthalocyanine derivative to the carbon black is not limited, a known method such as adding and dispersing the pigment in a basic solution of the phthalocyanine derivative using a disperser generally used for dispersing the pigment. It may be used.
As specific examples of particularly preferred phthalocyanine derivatives,
[0047]
Embedded image

[0048]
Embedded image

[0049]
Embedded image

[0050]
And the like. Of course, use is not limited to only these compounds.
It is conventionally known to use these dispersing aids for dispersing pigments. It is also known to use a photosensitive resin composition for forming a black matrix (Japanese Patent Application Laid-Open No. 10-204,321). However, in order to achieve the high properties desired for BM applications, in the system of the present invention using a pigment having specific primary physical properties and a polymer material having specific physical properties, these specific dispersing aids exhibit extremely favorable performance. That is not easy to imagine. The amount of these dispersing aids is preferably 0.1 to 50 parts by weight, particularly preferably 1 to 10 parts by weight, per 100 parts by weight of carbon black.
[0051]
As described below, the photosensitive resin composition of the present invention contains the above-described carbon black and the specific organic compound, and the photosensitive resin component. If necessary, other dispersants and dispersing aids may be used. May be contained.
[0052]
It is desirable that the above components are mixed in advance to prepare a carbon black dispersion, and the resin component is mixed therein. By preparing a carbon black dispersion in advance and achieving a desired degree of dispersion, it becomes easy to uniformly disperse carbon black in the resin composition.
[0053]
(Method for preparing dispersion liquid)
The dispersing means for preparing the carbon black dispersion is not particularly limited. Generally, carbon black, a dispersing agent, and a dispersing aid as needed are mixed with a dispersion medium, media such as glass beads and zirconia beads are added, and dispersed by a paint conditioner, a bead mill, a sand mill, a ball mill, a dissolver, a sand grinder, or the like. I do. The dispersion can also be carried out using a two-roll, three-roll, kneader, homogenizer system, jet mill, ultrasonic wave or the like. A plurality of these dispersing means may be combined. At this time, when a polymer compound which may be gelled by heat is used, a polymerization inhibitor such as hydroquinone may be added or cooled if necessary.
[0054]
The degree of dispersion is desirably adjusted so that the dispersed particle size of carbon black is 1 to 300 nm, preferably 50 to 300 nm, and more preferably 80 to 200 nm. The dispersion particle size here is an average particle size obtained by, for example, a known laser Doppler type particle size measuring device.
Carbon black is a very fine powder, and it is very difficult to achieve a desirable uniform dispersion because the primary particles form a so-called structure in which the primary particles are linked like a bunch of grapes or chains. Although it is presumed that this is one of the causes of not being able to obtain a theoretically attainable OD value, in the present invention, the combination of the specific carbon black and the specific organic compound described above It is easy to obtain such a preferable dispersion diameter, and it is considered that this contributes to a significant improvement in the performance of the final photosensitive resin composition.
[0055]
The viscosity of the dispersion is preferably adjusted to 3.0 to 200.0 mPa · s, more preferably 3.0 to 100.0 mPa · s, and still more preferably 3.0 to 30.0 mPa · s.
The viscosity here is the viscosity of the dispersion at a liquid temperature of 25 ° C., obtained from a known cone plate type viscosity type.
[0056]
When the dispersion is insufficient and the dispersion particle size is larger than the above range, undispersed carbon black called coarse particles remains, which causes a defect in the filtering step, and further adversely affects the surface roughness and pattern shape of the BM. Sometimes.
On the other hand, when the state is excessively dispersed, which is called overdispersion, a problem arises in an increase in dispersion viscosity and dispersion stability, which may adversely affect the coating properties of the photosensitive resin composition and the development characteristics.
In addition, even if there are coarse particles with insufficient dispersion, they can be removed by filtering and adjusted to the above-mentioned range of dispersed particle diameter. Further, even when the dispersion is sufficient, it is desirable to perform filtering for the purpose of removing foreign substances in the system, and the filtering may be performed using a normal filter.
[0057]
Thus, the carbon black dispersion of the present invention can be obtained.
In order to form a black matrix of a color filter, it is a general process to apply the composition to a transparent substrate, expose and cure as described below to form a black matrix. It is generally used as a photosensitive resin composition containing a resin component. The photosensitive resin composition of the present invention contains at least the above-described carbon black and a photosensitive resin component. Further, if necessary, a binder resin may be contained, and generally a solvent component is also contained. A so-called black matrix forming resist, a black paint composition, and a photosensitive resin composition correspond to various carbon black-containing compositions used for forming a black matrix of a color filter.
[0058]
(Photopolymerization initiator)
In order to cure the photosensitive resin composition by exposure, a photopolymerization initiator that absorbs light and generates radicals is generally contained. Examples of the photopolymerization initiator include benzyl; benzoin ether; benzoin isobutyl ether; benzoin propyl ether; benzoin isobutyl ether; benzophenone; benzoyl benzoic acid; 4-benzoyl-4'-methyldiphenyl sulfide; benzyl methyl ketal; -Butoxyel-4-methylaminobenzoate; 2-chlorothioxanthone 3,3'-dimethyl-4-methoxybenzophenone, benzoylbenzoic acid, methyl benzoylbenzoate; benzoylbenzoic acid ester, benzyldimethyl ketal, methylthioxanthone, ethylthioxanthone , Isopropylthioxanthone, dimethylthioxanthone, diethylthioxanthone, diisopropylthioxanthone, dimethylaminomethylbenzoate G, isoamyl dimethylaminobenzoate, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane -1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, methylbenzoylformate, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane- 1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′- Tetraphenylbisimidazole, 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetra- (4-methoxyphenyl B) One or more of various known photopolymerization initiators in a photosensitive resin composition such as bisimidazole may be appropriately selected and used.
It is desirable to add 0.5 to 30 parts by weight, preferably 1 to 25 parts by weight, based on 100 parts by weight of the solid content of the photosensitive resin composition.
[0059]
(Photosensitive resin component)
The photosensitive resin component is not particularly limited as long as it is a photosensitive photocrosslinkable or photopolymerizable compound that is cured by the action of a photopolymerization initiator. For example, a photopolymerizable compound having at least one ethylenically unsaturated double bond as described in JP-A-11-14822 is typical.
[0060]
Examples of the photopolymerizable compound having at least one ethylenically unsaturated double bond that can be used include the following compounds.
[0061]
Photocrosslinkable or photopolymerizable monomers, oligomers, and prepolymers include ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, pentaerythritol triacrylate, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, Esters of acrylic acid or methacrylic acid of monohydric or polyhydric alcohol such as pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate; condensation of polyhydric alcohol and monobasic acid Obtained by reacting (meth) acrylic acid with polyester prepolymer obtained by (Meth) acrylate; polyurethane (meth) acrylate obtained by reacting a compound having a polyol group and two isocyanate groups and then reacting with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol Epoxy resins such as S-type epoxy resin, novolak-type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin, amine epoxy resin, triphenolmethane-type epoxy resin, dihydroxybenzene-type epoxy resin And a usual photopolymerizable resin such as an epoxy (meth) acrylate obtained by reacting the polymer with (meth) acrylic acid.
In addition, (meth) acrylic acid is reacted with lower alcohols such as methanol, ethanol and propanol, and polyhydric alcohols such as (poly) ethylene glycol, (poly) propylene glycol, glycerin, methylolpropane, pentaerythritol and dipentaerythritol. Ester compound obtained, N-methylol melamine, N-methylol benzoguanamine, ester compound obtained by reacting (poly) N-methylol (meth) acrylamide and the like with (meth) acrylic acid, monomer copolymerizable with maleic anhydride Of a polymer obtained by polymerizing a compound with hydroxyethyl (meth) acrylic acid, an azido compound such as azidobenzophenone, azidochalcone, azidostilbene, azidobenzalcyclohexanone, methanol, ethanol Condensates of lower alcohols such as alcohol and propanol, polyhydric alcohols such as (poly) ethylene glycol, (poly) propylene glycol, glycerin, methylolpropane, pentaerythritol and dipentaerythritol and azidobenzoic acid, and (meth) acrylic Monomers such as acid, (meth) acrylic ester, acrylamide, acrylonitrile, vinyl acetate, vinylphenol, vinylbenzoic acid, styrene, maleic anhydride, vinylbutyral, chloroprene, vinyl chloride, vinylpyrrolidone, etc. Polymer compounds obtained by combining and polymerizing by a radical polymerization method, an ionic polymerization method, or the like are exemplified. These are used in an amount of 30 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the polymer compound in the black pigment composition.
The compounding ratio is 1 to 100 parts by weight, preferably 5 to 50 parts by weight, and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of carbon.
[0062]
These radically polymerizable monomers having an ethylenically unsaturated double bond can be used alone or in combination of two or more. For example, 2-ethyl, 2-butylpropanediol diacrylate, pentaerythritol tetraacrylate , Dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, polyoxyethylated trimethylolpropane triacrylate, tris (2-acryloyloxyethyl) isocyanurate, 1,4-diisopropenylbenzene, 1,4- Dihydroxybenzene methacrylate, decamethylene glycol diacrylate, ethylene glycol diacrylate, triethylene glycol acrylate, trimethylolpropane triacrylate, diallyl fumarate, etc. It is below. In particular, 2-butylpropanediol diacrylate, pentaerythritol tetraacrylate, dipentaeristol pentaacrylate, or polyoxyethylated trimethylolpropane triacrylate is preferred.
[0063]
Among these photopolymerizable compounds, compounds having an average molecular weight of 1000 or more have a very high photopolymerization rate, and it is particularly useful to incorporate these compounds into the photosensitive resin composition.
In particular, a photopolymerizable compound having an acidic group such as a carboxyl group and an ethylenically unsaturated double bond is preferably used. These compounds are extremely useful in increasing the content of the photopolymerizable compound having an ethylenically unsaturated double bond in the photosensitive resin, increasing the polymerization rate under atmospheric exposure, and enabling aqueous development. .
[0064]
Specific examples of the photopolymerizable compound having both an acidic group such as a carboxyl group and an ethylenically unsaturated double bond include bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin, and glycidyl polycarboxylate. Ester, polyol glycidyl ester, aliphatic or alicyclic epoxy resin, amine epoxy resin, triphenolmethane epoxy resin, dihydroxybenzene epoxy resin and other epoxy groups and hydroxy groups obtained by reacting (meth) acrylic acid Epoxy (meth) acrylate-carboxylic acid adducts can be copolymerized with maleic anhydride by reacting with acid anhydrides, and can be copolymerized with monomers such as ethylene, propene, isobutylene, styrene, vinylphenol, acrylic acid, acrylic acid esters and acrylamide. A half-esterified compound obtained by reacting the maleic anhydride part of the polymer with an acrylate having an alcoholic hydroxy group such as hydroxyethyl acrylate or an acrylate having an epoxy group such as glycidyl methacrylate Acrylic acid, acrylic acid ester and hydroxyethyl acrylate And a compound obtained by further reacting acrylic acid with an -OH group of an acrylate copolymer having an alcoholic hydroxy group.
[0065]
It is preferable to prepare the photosensitive resin composition so that the ratio of the photopolymerizable compound is 60% or more.
[0066]
(Binder resin)
The binder resin is generally an organic polymer substance that plays a role of a binder for improving a photopolymerizable layer such as compatibility, film forming property, developability, adhesiveness, etc., for example, as disclosed in JP-A-10-253,820. And JP-A-11-14,822.
[0067]
Specific examples include the following compounds.
Polyolefin polymers such as polyethylene, polypropylene and polyisobutylene; diene polymers such as polybutadiene and polyisoprene; polymers having a conjugated polyene structure such as polyacetylene polymers and polyphenylene polymers; polyvinyl chloride, polystyrene, vinyl acetate, polyvinyl alcohol, Vinyl polymers such as polyacrylic acid, polyacrylic acid ester, polyacrylamide, polyacrylonitrile, and polyvinyl phenol; polyphenylene ether, polyoxirane, polyoxetane, polytetrahydrofuran, polyether ketone, polyether such as polyacetal; novolak resin, resol resin, etc. Phenolic resin; polyethylene terephthalate, polyphenolphthalein terephthalate, polycarbonate Polyesters such as alkyd resins and unsaturated polyester resins; polyamides such as nylon-6, nylon 66, water-soluble nylon and polyphenylene amide; polypeptides such as gelatin and casein; novolak epoxy resins, bisphenol epoxy resins, novolak epoxy acrylates and acid anhydrides Resins such as modified resins and modified products thereof; polyurethanes, polyimides, melamine resins, urea resins, polyimidazoles, polyoxazoles, polypyrroles, polyanilines, polysulfides, polysulfones, celluloses and the like.
[0068]
For example, a copolymer of (meth) acrylic acid and an alkyl ester of (meth) acrylic acid (for example, a methyl group, an ethyl group, a butyl group, etc.); Copolymers with basic acid anhydrides may be mentioned. Further, a high molecular compound containing a carboxylic acid, a hydroxy group, an amino group, a carboxylic amide group, a sulfonamide group, or the like in a molecule is also included.
[0069]
Among these organic polymer substances, a photosensitive resin composition containing a resin having a carboxyl group, a phenolic hydroxyl group, or the like in a resin side chain or a main chain is preferable from the viewpoint of preventing pollution since it can be alkali-developed. In particular, a resin having a carboxyl group, for example, an acrylic acid (co) polymer, a styrene / maleic anhydride resin, an acid anhydride-modified resin of novolak epoxy acrylate, and the like are preferable because of high alkali developability.
[0070]
Further, acrylic resins are preferred because of their excellent developability, and various copolymers can be obtained by selecting various monomers, and thus are preferred from the viewpoint of performance and production control. More specifically, examples of the acrylic resin containing a carboxyl group include (meth) acrylic acid, (maleic anhydride) and the like, for example, various resins exemplified in JP-A-10-253,820.
[0071]
The added amount of these binder resins is preferably 40% by weight or less, particularly preferably 5 to 30% by weight of the total solid content. More preferably, the amount is 15 to 30% by weight. If the amount is less than 5% by weight, the adhesion strength between the substrate and the pattern is reduced, and if it exceeds 30% by weight, the photosensitivity is reduced.
For the purpose of improving heat resistance, an epoxy compound such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, and glycidyl polycarboxylate may be used. It is considered that the combination of an epoxy compound and a compound having a carboxylic acid reacts and crosslinks to improve heat resistance.
[0072]
Other heat-resistant resins such as a fluororesin, a silicone resin, a silicon-containing acrylic resin, a polyimide, a polyimide amide, a polydiphenyl ether, a poly (alkyleneimine), a phenol resin, and a xylene resin, alone or in combination of two or more. They can be used in combination.
Addition of such a heat-resistant resin can prevent a decrease in heat resistance even when a film formed from the composition for a liquid crystal panel of the present invention is subjected to a heat treatment at, for example, about 200 to 300 ° C. .
[0073]
(solvent)
The solvent used is not particularly limited, and the same solvent as that used for obtaining the carbon black dispersion may be used. Further, as a diluting solvent for improving the workability during the preparation of the photosensitive resin composition, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, ethyl carbitol acetate, diglyme, cyclohexanone, propylene glycol monomethyl ether acetate And organic solvents such as lactic acid esters.
[0074]
In addition, a silane coupling agent and a titanate coupling agent for improving the adhesion to the substrate as required, a fluorine-based, silicon-based, hydrocarbon-based surfactant and an ultraviolet absorber for improving the smoothness of the film. And various additives such as an antioxidant.
[0075]
Specific examples of the photosensitive resin composition include various kinds of so-called resist compositions that are known for use in color filters and for forming a black matrix. For example, either a polyfunctional acrylate monomer or a polyfunctional methacrylate monomer, an organic polymer binder, and a photopolymerization initiator composed of at least one selected from halomethyloxadiazole-based compounds and halomethyl-s-triazine-based compounds. (JP-B-6-95211), a photosensitive resin containing a photopolymerization initiator that absorbs light to generate radicals and a monomer that is cured by the action of the photopolymerization initiator. And more preferably those containing an organic polymer substance as a binder in order to improve the photopolymerizable layer such as compatibility, film forming property, developability, adhesiveness, etc. From the viewpoint of prevention, it is preferable to have a carboxyl group or a phenolic hydroxyl group in the resin side chain or main chain as an organic polymer substance as a preferable one Fatty acid-containing monomers that are cured by the action of the photopolymerization initiator. Known monomers such as monomers that undergo radical polymerization by the action of radicals generated by the photopolymerization initiator and monomers that undergo addition condensation by the action of acids generated from the photopolymerization initiator. And a resist containing a combination of an acrylic resin containing a carboxyl group and an acrylic monomer (Japanese Patent Application Laid-Open No. 10-253,820).
[0076]
Further, in addition to carbon black, a photosensitive resin composition containing a binder resin, a monomer having an ethylenically unsaturated double bond, and a photopolymerization initiator (Japanese Patent Application Laid-Open No. 11-14822), together with carbon black, And a compound having at least one ethylenically unsaturated double bond capable of being polymerized by addition of a photopolymerization initiation system that generates a radical by absorbing the compound (ethylenic compound). A photopolymerizable composition (Japanese Patent Laid-Open No. 11-80,584) containing an organic polymer substance (binder resin), a dispersant, and the like, a copolymer containing hydroxystyrene as a main component, a crosslinking agent, The copolymer containing a photoacid generator and carbon black and containing hydroxystyrene as a main component has a hydroxystyrene unit content of at least 50 mol%. Black photosensitive composition (JP-A-11-24269), which is a copolymer containing 5 to 30 mol% of a monomer unit having a carboxylic acid group, phenol having (A) cresol in addition to carbon black -Soluble resin obtained by condensation of aldehydes and aldehydes, (B) an acid-crosslinkable methylolated melamine resin, and (C) a halogen-containing triazine compound having a specific structure capable of absorbing light to generate an acid. Black matrix forming materials (JP-A-11-143,056) and the like.
[0077]
A photosensitive resin composition containing a hindered phenolic antioxidant (Japanese Patent Application Laid-Open No. 2002-22925), and a photosensitive resin obtained by introducing a carboxyl group into a molecule to impart water solubility. Epoxy resins having two or more epoxy groups in one molecule such as novolak type epoxy resin, bisphenol type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, etc. Carboxyl group-containing epoxy (meth) acrylate obtained by reacting an acid anhydride with a hydroxyl group generated when reacting with an unsaturated monobasic acid such as (meth) acrylic acid, copolymerizable with maleic anhydride Ethylene, propylene, isobretine, styrene, vinylphenol, (meth) acrylic acid, Compounds obtained by half-esterification by reacting (meth) acrylate having an alcoholic hydroxyl group such as hydroxyethyl (meth) acrylate with the maleic anhydride part of a copolymer with a monomer such as acrylate or acrylamide, or trimethylol Examples thereof include half-esterified products of a hydroxyl group-containing (meth) acrylate such as propane di (meth) acrylate and pentaerythritol tri (meth) acrylate with an acid anhydride (Japanese Patent Application Laid-Open No. 8-337,736).
[0078]
In recent years, a cardo-type polymer known as a polymer material having high heat resistance, solvent solubility, high transparency, high refractive index, low birefringence, and high gas permeability has been used for forming color filters including BM. It is known as a photosensitive resin component. The cardo type polymer is a general term for polymers having a structure in which a cyclic group is directly bonded to a polymer main chain. However, the presence of a bulky substituent in the main chain results in (1) rotation constraint of the polymer main chain, (2) conformational regulation of the main chain and side chain, (3) inhibition of intermolecular packing, (4) increase in aromaticity due to introduction of an aromatic substituent on the side chain, and the like, and furthermore, characteristics in physical properties It is said to exhibit higher gas permeability in addition to high heat resistance, solvent solubility, high transparency, high refractive index, low birefringence, and the like.
[0079]
Such cardo-type polymers, in particular, cardo-type polymers having a fluorene skeleton represented by the following formulas (I) to (V) have been proposed as photosensitive resins for color filters (Japanese Patent Publication No. Hei 7 (1994)). -35,426, JP-A-7-48424, JP-A-9-241,339, JP-A-9-241,340, JP-A-9-304,929, JP-A-9-325 , 494, JP-A-9-328,534), and such a cardo type polymer can be particularly preferably used as a photosensitive resin component in the photosensitive resin composition of the present invention.
[0080]
Formula (I):
[0081]
Embedded image

[0082]
(In the formula (I), R represents either a hydrogen atom or a methyl group, and n is an integer of 0 to 20.)
[0083]
Formula (II):
Embedded image

[0084]
(In the formula (II), n is an integer of 1 or more.)
[0085]
Formula (III):
[0086]
Embedded image

[0087]
(In the formula (III), n is an integer of 1 or more)
Formula (IV):
[0088]
Embedded image

[0089]
(In the formula (IV), R1 and R2 represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen atom, n represents a number of 1 to 5. A represents a tetravalent organic residue, and X represents 1 The above numbers are shown.)
[0090]
Formula (V):
[0091]
Embedded image

[0092]
(In the formula (V), R represents H or a lower alkyl group, R ′ represents H or a methyl group, and n is an integer of 0 to 20.)
[0093]
In addition to the above-described carbon black, photosensitive resin component, and the like, a pigment other than carbon black may be blended. For example, black low-order titanium oxynitride, titanium oxide, barium sulfate, zinc white, lead sulfate, yellow lead, manganese purple, cobalt purple, barium sulfate, red iron oxide, ultramarine blue, chromium oxide, antimony white, iron black, lead black, sulfide One or more of metal oxides such as zinc, cadmium yellow, cadmium red, zinc, and magnesium carbonate, metal sulfides, sulfates, metal hydroxides, metal carbonates, and the like are included. However, in this case, it is desirable to keep the amount to not more than 20 parts by weight, preferably not more than 10 parts by weight based on 100 parts by weight of the total amount of carbon black, from the viewpoint of preventing the deterioration of the developing property and the OD value.
[0094]
When the solid content of the photosensitive resin composition is 100 parts by weight, the proportion of carbon black is 5 to 70 parts by weight, preferably 10 to 60 parts by weight, and the proportion of the organic pigment is 40 parts by weight or less, preferably 30 parts by weight. Parts by weight or less, the proportion of inorganic pigments other than carbon is 60 parts by weight or less, preferably 50 parts by weight or less, and the total pigment proportion is 20 to 80 parts by weight, preferably 30 to 75 parts by weight. Can be. When the total pigment ratio is less than 20 parts by weight, the light-shielding property is not sufficient, and when it exceeds 80 parts by weight, inconveniences such as a decrease in sensitivity and a decrease in coatability may occur.
[0095]
The above-mentioned materials are mixed using a stirrer such as a dissolver type stirrer, a turbo type stirrer, and a twin-screw stirrer to obtain a photosensitive resin composition, or a two-roll mill, a three-roll mill, a sand mill, and a paint. The photosensitive resin composition is kneaded using a disperser such as a shaker, and the preferable amount of the above-mentioned organic solvent used at that time is usually 50 to 200% by weight of the total solids.
[0096]
The photosensitive resin composition of the present invention is excellent in conductivity, and has high coloring power and hiding power, and can be particularly suitably used, for example, for forming a black matrix in a liquid crystal display or the like.
[0097]
When the heat-resistant resin is blended, the amount used is preferably 3% by weight or more, especially 5%, in order to impart sufficient heat resistance to the photosensitive resin composition of the present invention. % By weight or more, and when the composition contains the above-mentioned photopolymerizable monomer and prepolymer, in order to allow the crosslinking reaction between the two to proceed sufficiently, It is preferable to adjust the content in the photosensitive resin composition so as to be 50% by weight or less, especially 30% by weight or less.
[0098]
In order to impart sufficient conductivity to the obtained BM, the mixing ratio of each component is generally 1 part by weight or more, particularly 5 parts by weight, of the above-mentioned specific organic compound defined in the present invention with respect to 100 parts by weight of carbon black. It is preferably at least 100 parts by weight, more preferably at most 100 parts by weight, more preferably at most 60 parts by weight, based on 100 parts by weight of carbon black in order to sufficiently exhibit the hiding power of carbon black. The compounding amount of the dispersion medium is generally a value obtained by subtracting carbon black, the above-mentioned specific organic compound, and a dispersing aid from 100 parts by weight of the solid of the photosensitive resin composition.
[0099]
The above-described photosensitive resin composition is applied to a substrate, irradiated with radiation, and cured to form a black matrix of a color filter.
Usually, it is created as follows. A method such as a spin coating method, a roll coating method, a printing method, and a bar coating method is used on a substrate such as a glass substrate. Coating is performed so that the film thickness is usually 0.5 to 5 μm, and prebaking is performed to form a film. Next, the entire surface is irradiated with radiation (for example, X-rays, electron beams, ultraviolet rays, visible rays, and preferably ultraviolet rays) and subjected to treatment such as post-baking to obtain a black cured film. The obtained black cured film has high light-shielding properties and high adhesion to substrates. The image exposure for forming a pattern is performed by irradiating an ultraviolet or visible light source onto the photopolymerizable layer through a negative matrix pattern mask. As the alkali developer, an inorganic alkali agent such as sodium carbonate, potassium carbonate, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide and the like is used.
[0100]
For example, as shown in FIG. 2A, a photosensitive resin composition is coated on a transparent substrate (1) such as a glass substrate by a known method such as a bar coating method, a roll coating method, a spinner method, or a curtain coating method. It is applied uniformly by means to form a black resin layer (2). When drying is required, heating may be performed at a temperature of about 70 to 100 ° C. By setting the thickness of the black resin layer to preferably 1.5 μm or less, particularly preferably 1.0 μm or less, the overlap thickness with a plurality of color pixels to be performed in the next step is reduced.
[0101]
Next, as shown in FIG. 2B, pattern exposure is performed by irradiating ultraviolet light through a mask (3) to cure the photosensitive resin composition. As a light source used for exposure, a high-pressure mercury lamp and an ultra-high-pressure mercury lamp can be used. Subsequently, using an aqueous alkali solution such as an alkali metal salt such as sodium carbonate, an alkali metal hydroxide such as sodium hydroxide, or a hydrooxane organic base such as tetramethylammonium as a developer, the black resin layer in the unexposed portion is removed. Then, a black matrix (4) composed of a black resin layer is formed on the transparent substrate (FIG. 2C).
[0102]
Next, as shown in FIG. 2D, a plurality of color pixels (5) are provided in a form having an overlap margin with the black matrix to form a desired color filter. As another method, as shown in FIG. 3A, a photosensitive resin composition is coated on a transparent substrate (1) on which a plurality of color pixels (5) are formed in advance by a bar coating method or a roll coating method. A black resin layer (2) is formed by coating by a known method such as a spin coating method, a spin coating method, or a curtain coating method (FIG. 3B).
[0103]
After drying if necessary, the photosensitive resin composition is cured by irradiating the back surface of the transparent substrate with ultraviolet light using the color pixels as a mask (FIG. 3 (c)).
[0104]
Further, the black resin layer in the unexposed portions is removed by performing alkali development and washing with water to form a black matrix (4) on the substrate, and a color filter is formed through drying and the like (FIG. 3 (d)). .
[0105]
By forming a resist pattern using the carbon black dispersion or the photosensitive resin composition of the present invention, excellent development characteristics can be obtained. This is presumably because the carbon black-containing resin composition of the present invention has high sensitivity to ultraviolet light transmitted through the coating film. For this reason, the carbon black content can be increased, and a high OD value can be obtained, whereby the pattern can be made thinner.
[0106]
Further, the carbon black dispersion and the photosensitive resin composition of the present invention are easy to adjust the resistance, and have a surface resistance of 10%. ⁴ -10 ¹⁴ Since it can be adjusted to a wide range of about Ω · cm, it can be suitably used for the low-resistance resin BM. That is, a low-resistance resin BM having a high OD value and excellent developability can be obtained.
[0107]
【Example】
The present invention will be described more specifically with reference to examples. “Parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified.
[0108]
[Example 1]
(Preparation of carbon black dispersion)
20 parts by weight of commercially available carbon black (average primary particle diameter 24 nm, DBP oil absorption 100 ml / 100 g, pH 3.0), commercially available polymer dispersant A (polyurethane polymer compound, amine value 45 mgKOH / g, weight average molecular weight) 8,000, acid value 0) to 4.8 parts by weight (in terms of solid content), 0.6 parts by weight of a commercially available copper phthalocyanine derivative as a dispersing aid, and 74.6 parts by weight of propylene glycol monoethyl ether acetate. The mixture was mixed and stirred using a bead mill to obtain a carbon black dispersion.
[0109]
(Measurement of liquid properties)
(1) Dispersion stability (viscosity change)
The dispersion stability was measured by accelerating the carbon black-containing composition at a temperature of 40 ° C. and measuring the change in viscosity for one month. Table 3 shows the measurement results. ○ indicates that the viscosity change is within 5%, and X indicates that the change is 5% or more.
[0110]
(2) Dispersibility (dispersion particle size)
The average dispersed particle size of the obtained carbon black dispersion was measured using a Coulter N4 type particle size measuring device (manufactured by Beckman Coulter, Inc.). As a diluting solvent, propylene glycol monomethyl ether acetate was used. Table 3 shows the measurement results.
[0111]
(3) Operability (viscosity)
The viscosity of the carbon black dispersion at 25 ° C. was measured using a cone-plate viscometer (ELD manufactured by TOKIMEC). Table 3 shows the measurement results.
[0112]
(Preparation of photosensitive resin composition)
After diluting 20 parts of a prepolymer (epoxy acrylate) and 10 parts of a photopolymerizable monomer (dipentaerythritol hexaacrylate) with 70 parts by weight of propylene glycol monomethyl ether acetate, 2 parts of a photopolymerization initiator (2,4 diethylthioxanthone) Was added to prepare a resin solution for dilution.
[0113]
50 parts of the carbon black dispersion, 30 parts of the resin solution for dilution and 20 parts of propylene glycol monomethyl ether acetate were mixed and stirred to obtain a photosensitive resin composition as a resist for forming a black matrix. Using this resin composition, physical properties were measured according to the following methods.
[0114]
(Formation of black matrix)
The above photosensitive resin composition was applied to a glass substrate by a spin coater, and prebaked on a hot plate at 80 ° C. to form a coating film having a thickness of about 1 μm. Next, the sample coating film was image-exposed with a high-pressure mercury lamp, immersed and developed in a potassium hydroxide solution having a temperature of 25 ° C. and a concentration of 0.05%, and further post-baked on a hot plate at 220 ° C. for 30 minutes. To form a black matrix.
[0115]
[Measurement of physical properties of BM]
(1) OD value
The OD value of the pattern part of the black matrix after development was measured using a “Macbeth (registered trademark) densitometer” (TR-927 orthomatic type). Table 3 shows the results.
[0116]
(2) Developability
(1) Pattern shape
The shape of the pattern of the black matrix was observed with an optical microscope.
The evaluation was evaluated as ○ when the pattern edge was free from rattling, and as X when the pattern edge was rattling. Table 3 shows the results.
[0117]
▲ 2 ▼ Adhesion
A 2 mm × 2 mm square flaw is cut in a 10 mm × 10 mm square in a grid pattern on the pattern portion of the developed black matrix with a cutter knife, and the scratch is made with Cellotape LP-18 (registered trademark) (Nichiban Co., Ltd.). Was adhered, a 500 g weight was placed thereon, and after standing for 10 minutes, the adhesion was evaluated by peeling.
The evaluation was evaluated as ○ when the peeling of the coating film was within 5 places, and as X when the peeling was 15 or more places. This evaluation was performed at two locations in the same substrate. Table 3 shows the results.
[0118]
(3) Surface resistance value
The surface resistance of the black matrix was measured with a surface resistance meter (manufactured by Mitsubishi Chemical Corporation, "Hiresta UP" (Loresta?), Measuring probe URS, applied voltage 10 V).
For the sample whose surface resistance was too high and exceeded the upper limit of measurement (display OVER), the applied voltage was further changed to 1000 V and measured. Table 3 shows the results.
[0119]
[Example 2]
20 parts by weight of the carbon black used in Example 1 and 2.4 parts by weight of a commercially available polymer dispersant A ((polyurethane-based compound, amine value 45 mgKOH / g, weight average molecular weight 8,000, acid value 0)). Parts (in terms of solids) and 2 parts by weight (in terms of solids) of another commercially available polymer dispersant B (polyurethane-based compound, amine value 32 mg KOH / g, molecular weight 10,000), and used as a dispersing aid. 0.8 parts by weight of the same commercially available copper phthalocyanine derivative as used in Example 1 and 74.8 parts by weight of propylene glycol monoethyl ether acetate were added, and mixed and stirred using a bead mill to obtain a carbon black dispersion. .
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0120]
Example 3
A carbon black dispersion was obtained in the same manner as in Example 1, except that commercially available carbon black having an average primary particle diameter of 21 nm, a DBP oil absorption of 65 ml / 100 g, and a pH of 3.0 was changed to 20 parts by weight. Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0121]
Example 4
20 parts by weight of carbon black having an average primary particle diameter of 24 nm, a DBP oil absorption of 100 ml / 100 g, and a pH of 2.7, a commercially available polymer dispersant A (polyurethane polymer compound, amine value of 45 mgKOH / g, weight average molecular weight of 8,000 4.8 parts by weight (acid value 0), 0.6 parts by weight of a commercially available copper phthalocyanine derivative as a dispersing aid, and 74.6 parts by weight of propylene glycol monoethyl ether acetate. The mixture was mixed and stirred to obtain a carbon black dispersion.
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0122]
Example 5
Example 4 was carried out in the same manner as in Example 4, except that carbon black having an average primary particle diameter of 24 nm, a DBP oil absorption of 100 ml / 100 g, and a pH of 3.5 was changed to 20 parts by weight. Table 3 shows the results.
[0123]
Comparative Example 1
20 parts by weight of commercially available carbon black (average primary particle diameter 55 nm, DBP oil absorption 93 ml / 100 g, pH 3.0), commercially available polymer dispersant A (polyurethane polymer compound, amine value 45 mgKOH / g, molecular weight 8, 000, acid value 0) to 4.8 parts by weight (in terms of solid content), 0.6 parts by weight of a commercially available copper phthalocyanine derivative as a dispersing aid, and 74.6 parts by weight of propylene glycol monoethyl ether acetate. The mixture was mixed and stirred using a bead mill to obtain a carbon black dispersion.
[0124]
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0125]
Comparative Example 2
20 parts by weight of carbon black having an average primary particle diameter of 24 nm, a DBP oil absorption of 100 ml / 100 g, and a pH of 3.0; 4.8 parts by weight (average molecular weight: 15,000), 0.6 parts by weight of a commercially available copper phthalocyanine derivative as a dispersing aid, and 74.6 parts by weight of propylene glycol monoethyl ether acetate as a dispersion medium. The mixture was mixed and stirred at 25 ° C. using a bead mill to obtain a carbon black dispersion.
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0126]
Comparative Example 3
20 parts by weight of carbon black having an average primary particle diameter of 24 nm, a DBP oil absorption of 100 ml / 100 g, and a pH of 3.0, and a commercially available polymer dispersant D (polyurethane polymer compound, amine value 37 mgKOH / g, weight average molecular weight 20,000) to 4.8 parts by weight (in terms of solid content), 0.6 parts by weight of a commercially available copper phthalocyanine derivative as a dispersing aid, and 74.6 parts by weight of propylene glycol monoethyl ether acetate as a dispersion medium. Was mixed and stirred at 25 ° C. to obtain a carbon black dispersion.
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0127]
Comparative Example 4
A carbon black dispersion was obtained in the same manner as in Example 1 except that carbon black having an average primary particle diameter of 24 nm, a DBP oil absorption of 98 ml / 100 g, and a pH of 7.7 was used.
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0128]
Comparative Example 5
A carbon black dispersion was obtained in the same manner as in Example 1 except that carbon black having an average primary particle diameter of 50 nm, a DBP oil absorption of 175 ml / 100 g, and a pH of 7 was used.
Liquid physical properties were measured in the same manner as in Example 1. Table 3 shows the results. Further, (preparation of photosensitive resin composition), (formation of black matrix) and (measurement of physical properties of BM) were performed in the same manner as in Example 1. Table 3 shows the results.
[0129]
Physical properties of carbon black and polymer dispersant used in Examples 1 to 5 and Comparative Examples 1 to 5 (primary particle diameter, DBP oil absorption and pH, type of polymer, weight average molecular weight, amine value and acid value, respectively) ) And the types of dispersion aids are shown in Table 1. Table 2 shows the relationship between the physical properties of the carbon black used and the physical properties of the polymer dispersant. Table 2 shows the relationship between the amine value and the weight average molecular weight of the polymer dispersant used. In each table, "molecular weight" represents "weight average molecular weight" and is determined by the following measurement method.
Sample preparation: 15 mg of a sample is dissolved by adding 3 ml of a mobile phase for GPC measurement, and filtered with 0.45 μm hydrophilic PTFE (Millix-LH: manufactured by Nippon Millipore).
Equipment: 515 high-pressure pump, 717plus automatic injection equipment (Nippon Waters)
RI-101 (manufactured by Showa Denko KK)
Column: PLgel 5 MIXED-D (600 × 7.5 mm) (manufactured by Polymer Laboratories)
Column temperature: normal temperature
Mobile phase: THF 0.03% BHT added
Flow rate: 1.0 ml / min
Detection: RI
Injection volume: 50 μL
[0130]
[Table 1]

[0131]
[Table 2]

[0132]
[Table 3]

[0133]
As is clear from the above Examples and Comparative Examples, the carbon black dispersion of the present invention and the photosensitive resin composition of the present invention are excellent in operability. It can be seen that a matrix can be formed.
[0134]
【The invention's effect】
According to the present invention, a carbon black dispersion liquid and a carbon black-containing resin composition excellent in operability can be provided, and by using these, a black matrix excellent in both developability and OD value can be formed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a manufacturing process of a color filter.
FIG. 2 is an explanatory view showing a manufacturing process of a color filter.
[Explanation of symbols]
1 Transparent substrate
2 Black resin layer
3 Mask
4 Black Matrix
5 color pixels

Claims (7)

It contains carbon black having an average primary particle diameter of 20 to 30 nm, a DBP absorption of 140 ml / 100 g or less, and a pH of 2.5 to 4, and an organic compound having an amine value of 1 to 100 mgKOH / g and a weight average molecular weight of 5,000 to 12,000. Carbon black dispersion. The carbon black dispersion according to claim 1, which is used for forming a black matrix. Carbon black having an average primary particle diameter of 20 to 30 nm, a DBP absorption of 140 ml / 100 g or less, and a pH of 2.5 to 4, an organic compound having an amine value of 1 to 100 mgKOH / g, a weight average molecular weight of 5,000 to 12,000, A photosensitive resin composition comprising a resin component. A photosensitive resin composition obtained by mixing a photosensitive resin component with the carbon black dispersion according to claim 1. 5. The photosensitive resin composition according to claim 3, which is used for forming a black matrix. A black matrix obtained by applying and curing the photosensitive resin composition according to claim 5 on a substrate. A color filter comprising the black matrix according to claim 6.

Images