JP2004285170A - Oily ink composition for ink-jet printer, electrophotographic liquid developer, and method for producing colored resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oily ink for ink-jet printer, with a colorant dispersed homogeneously in microparticles, good in dispersion stability of the colorant dispersion, high in jet stability enough to cause no cloggings at a nozzle, and excellent in dryability on printing paper and both water resistance and light resistance of printed images, and also having high fretting resistance. <P>SOLUTION: The oily ink contains colored resin particles which are obtained by the following process: using seed particles consisting of colored component microparticles obtained by dispersing a colored component as a surface-treated colorant in a non-aqueous solvent 1.5-20 in dielectric constant and 15-60 mN/m( at 25°C ), at least one monofunctional monomer(M) and at least one dispersion stabilizer(P) as a polymer comprising recurring unit of specific structure with part of the main chain thereof crosslinked, soluble to the non-aqueous solvent, are added to the non-aqueous solvent followed by carrying out a dispersion polymerization in the presence of a polymerization initiator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１３】
一般式（Ｉ）中、Ｘ^１は−ＣＯＯ−、−ＯＣＯ−、−（ＣＨ_２）_ｋ−ＯＣＯ−、−（ＣＨ_２）_ｋ−ＣＯＯ−及び−Ｏ−から選ばれた１種或いはそれらの組み合わされた連結基を表わす。ｋは１〜３の整数を表す。 ａ^１とａ^２は、互いに同じでも異なってもよく、それぞれ水素原子、ハロゲン原子、シアノ基、炭化水素基、−ＣＯＯ−Ｚ^１又は炭化水素を介した−ＣＯＯ−Ｚ^１ （Ｚ^１は水素原子又は置換されてもよい炭化水素基を示す）を表す。Ｙ^１は炭素数６〜３２の脂肪族基を表す。
【００１４】
（２） 着色剤が有機顔料及び無機顔料から選択された少なくとも一種の顔料であり、着色成分が、該着色剤をポリマー被覆することにより表面処理されたものである上記（１）記載のインクジェットプリンタ用油性インク組成物。
（３） シード粒子が、表面処理された着色成分を顔料分散剤により非水溶媒中に微粒子状に分散安定化して得た着色成分微粒子である上記（１）記載のインクジェットプリンタ用油性インク組成物。
【００１５】
（４） 体積比抵抗１０^９Ωｃｍ以上の非水溶媒中に、着色剤を表面処理した着色成分を該非水溶媒中に微粒子状に分散して得た着色成分微粒子をシード粒子として、一官能性単量体（Ｍ）の少なくとも一種と、上記一般式（Ｉ）で示される繰返し単位を含有する重合体で、且つ、その重合体主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）の少なくとも一種とを加えた分散液を、重合開始剤の存在下に分散重合させることにより得られる着色樹脂粒子を含有することを特徴とする電子写真用液体現像剤。
【００１６】
（５） 有機顔料及び無機顔料から選択された少なくとも一種の顔料であり、着色成分が、該着色剤をポリマー被覆することにより表面処理されたものである上記（４）記載の電子写真用液体現像剤。
（６） シード粒子が、表面処理された着色成分を顔料分散剤により非水溶媒中に微粒子状に分散安定化して得た着色成分微粒子である上記（４）記載の電子写真用液体現像剤。
【００１７】
（７） 比誘電率１．５〜２０及び表面張力１５〜６０ｍＮ／ｍ（２５℃において）を有する非水溶媒中に、着色剤を表面処理した着色成分を該非水溶媒中に微粒子状に分散して得た着色成分微粒子をシード粒子として、一官能性単量体（Ｍ）の少なくとも一種と、上記一般式（Ｉ）で示される繰返し単位を含有する重合体で、且つ、その重合体主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）の少なくとも一種とを加えた分散液を、重合開始剤の存在下に分散重合させることにより得られる着色樹脂粒子の製造方法。
（８） 着色剤が有機顔料及び無機顔料から選択された少なくとも一種の顔料であり、着色成分が、該着色剤をポリマー被覆することにより表面処理されたものである請求項７の着色樹脂粒子の製造方法。
（９） シード粒子が、表面処理された着色成分を顔料分散剤により非水溶媒中に微粒子状に分散安定化して得た着色成分微粒子である前記（７）記載の着色樹脂粒子の製造方法。
【００１８】
【発明の実施の形態】
以下に本発明について詳細に述べる。
本発明のインクジェットプリンタ用油性インク組成物に使用される非水溶媒（分散媒）は、非極性の絶縁性溶剤であり、比誘電率１．５〜２０及び表面張力１５〜６０ｍＮ／ｍ（２５℃において）であることが好ましい。また電子写真用液体現像剤に使用される非水溶媒は、体積比抵抗１０^９Ωｃｍ以上であることが好ましい。更に望まれる特性としては、毒性の少ないこと、引火性が少ないこと、臭気が少ないことである。
【００１９】
かかる非水溶媒としては、直鎖状もしくは分岐状の脂肪族炭化水素、脂環式炭化水素、芳香族炭化水素、石油ナフサ及びこれらのハロゲン置換体等から選ばれた溶媒が挙げられる。例えばヘキサン、オクタン、イソオクタン、デカン、イソデカン、デカリン、ノナン、ドデカン、イソドデカン、エクソン社のアイソパーＥ、アイソパーＧ、アイソパーＨ、アイソパーＬ、フィリップ石油社のソルトール、出光石油化学社のＩＰソルベント、石油ナフサではシェル石油化学社のＳ．Ｂ．Ｒ．シェルゾール７０、シエルゾール７１、モービル石油社のベガゾール等から選ばれた溶媒を単独あるいは混合して用いることができる。
【００２０】
好ましい炭化水素溶剤としては、沸点が１５０〜３５０℃の範囲にある高純度のイソパラフィン系炭化水素が挙げられ、市販品としては前述のエクソン化学製のアイソパーＧ，Ｈ，Ｌ，Ｍ，Ｖ（商品名）、ノーパー１２，１３，１５（商品名）、出光石油化学製のＩＰソルベント１６２０，２０２８（商品名）、日本石油化学製のアイソゾール３００，４００（商品名）、アムスコＯＭＳ、アムスコ４６０溶剤（アムスコ；スピリッツ社の商品名）等が挙げられる。
これらの製品は、極めて純度の高い脂肪族飽和炭化水素であり、２５℃における粘度は３ｃＳｔ以下、２５℃における表面張力は２２．５〜２８．０ｍＮ／ｍ、２５℃における比抵抗は１０^１０Ω・ｃｍ以上である。また、反応性が低く安定であり、低毒性で安全性が高く、臭気も少ないという特徴がある。
ハロゲン置換の炭化水素系溶媒としてフルオロカーボン系溶媒があり、例えばＣ_７Ｆ_１６、Ｃ_８Ｆ_１８などのＣ_ｎＦ_２ｎ＋２で表されるパーフルオロアルカン類（住友３Ｍ社製「フロリナートＰＦ５０８０」、「フロリナートＰＦ５０７０」（商品名）等）、フッ素系不活性液体（住友３Ｍ社製「フロリナートＦＣシリーズ」（商品名）等）、フルオロカーボン類（デュポンジャパンリミテッド社製「クライトックスＧＰＬシリーズ」（商品名）等）、フロン類（ダイキン工業株式会社製「ＨＣＦＣ−１４１ｂ 」（商品名）等）、［Ｆ（ＣＦ_２）_４ＣＨ_２ＣＨ_２Ｉ］、［Ｆ（ＣＦ_２）_６Ｉ］等のヨウ素化フルオロカーボン類（ダイキンファインケミカル研究所製「Ｉ−１４２０」、「Ｉ−１６００」（商品名）等）等がある。
【００２１】
本発明で使用される非水系の溶媒として、更に高級脂肪酸エステルや、シリコーンオイルも使用できる。シリコーンオイルの具体例としては、低粘度の合成ジメチルポリシロキサンが挙げられ、市販品としては、信越シリコーン製のＫＦ９６Ｌ（商品名）、東レ・ダウコーニング・シリコーン製のＳＨ２００（商品名）等がある。
シリコーンオイルとしてはこれらの具体例に限定されるものではない。これらのジメチルポリシロキサンは、その分子量により非常に広い粘度範囲のものが入手可能であるが、１〜２０ｃＳｔの範囲のものを用いるのが好ましい。これらのジメチルポリシロキサンは、イソパラフィン系炭化水素同様、１０^１０Ω・ｃｍ以上の体積抵抗率を有し、高安定性、高安全性、無臭性といった特徴を有している。またこれらのジメチルポリシロキサンは、表面張力が低いことに特徴があり、１８〜２１ｍＮ／ｍの表面張力を有している。
【００２２】
上記の有機溶媒とともに、混合して使用できる溶媒としては、アルコール類（例えばメチルアルコール、エチルアルコール、プロピルアルコール、ブチルアルコール、フッ化アルコール等）、ケトン類（例えばアセトン、メチルエチルケトン、シクロヘキサノン等）、カルボン酸エステル類（例えば酢酸メチル、酢酸エチル、酢酸プロピル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル等）、エーテル類（例えばジエチルエーテル、ジプロピルエーテル、テトラヒドロフラン、ジオキサン等）及びハロゲン化炭化水素類（例えばメチレンジクロリド、クロロホルム、四塩化炭素、ジクロロエタン、メチルクロロホルム等）、等の溶媒が挙げられる。
【００２３】
次に、本発明の表面処理された着色成分について詳細に述べる。
本発明の表面処理された着色成分（以下単に「着色成分」と称することもある）は、着色剤を表面処理したものであり、該着色剤としては、特に限定されるものではなく、一般に市販されているすべての有機顔料及び無機顔料が挙げられる。
【００２４】
例えば、イエロー色を呈するものとして、Ｃ．Ｉ．ピグメントイエロー１（ファストイエローＧ等）、 Ｃ．Ｉ．ピグメントイエロー７４の如きモノアゾ顔料、 Ｃ．Ｉ．ピグメントイエロー１２（ジスアジイエローＡＡＡ等）、 Ｃ．Ｉ．ピグメントイエロー１７の如きジスアゾ顔料、 Ｃ．Ｉ．ピグメントイエロー１８０の如き非ベンジジン系のアゾ顔料、 Ｃ．Ｉ．ピグメントイエロー１００（タートラジンイエローレーキ等）の如きアゾレーキ顔料、 Ｃ．Ｉ．ピグメントイエロー９５（縮合アゾイエローＧＲ等）の如き縮合アゾ顔料、 Ｃ．Ｉ．ピグメントイエロー１１５（キノリンイエローレーキ等）の如き酸性染料レーキ顔料、 Ｃ．Ｉ．ピグメントイエロー１８（チオフラビンレーキ等）の如き塩基性染料レーキ顔料、フラバントロンイエロー（Ｙ−２４）の如きアントラキノン系顔料、イソインドリノンイエロー３ＲＬＴ（Ｙ−１１０）の如きイソインドリノン顔料、キノフタロンイエロー（Ｙ−１３８）の如きキノフタロン顔料、イソインドリンイエロー（Ｙ−１３９）の如きイソインドリン顔料、 Ｃ．Ｉ．ピグメントイエロー１５３（ニッケルニトロソイエロー等）の如きニトロソ顔料、 Ｃ．Ｉ．ピグメントイエロー１１７（銅アゾメチンイエロー等）の如き金属錯塩アゾメチン顔料等が挙げられる。
【００２５】
マゼンタ色を呈するものとして、Ｃ．Ｉ．ビグメントレッド３（トルイジンレッド等）の如きモノアゾ系顔料、 Ｃ．Ｉ．ビグメントレッド３８（ピラゾロンレッドＢ等）の如きジスアゾ顔料、 Ｃ．Ｉ．ビグメントレッド５３：１（レーキレッドＣ等）やＣ．Ｉ．ビグメントレッド５７：１（ブリリアントカーミン６Ｂ）の如きアゾレーキ顔料、 Ｃ．Ｉ．ビグメントレッド１４４（縮合アゾレッドＢＲ等）の如き縮合アゾ顔料、 Ｃ．Ｉ．ビグメントレッド１７４（フロキシンＢレーキ等）の如き酸性染料レーキ顔料、 Ｃ．Ｉ．ビグメントレッド８１（ローダミン６Ｇ’レーキ等）の如き塩基性染料レーキ顔料、 Ｃ．Ｉ．ビグメントレッド１７７（ジアントラキノニルレッド等）の如きアントラキノン系顔料、Ｃ．Ｉ．ビグメントレッド８８（チオインジゴボルドー等）の如きチオインジゴ顔料、 Ｃ．Ｉ．ビグメントレッド１９４（ペリノンレッド等）の如きペリノン顔料、 Ｃ．Ｉ．ビグメントレッド１４９（ペリレンスカーレット等）の如きペリレン顔料、 Ｃ．Ｉ．ビグメントレッド１２２（キナクリドンマゼンタ等）の如きキナクリドン顔料、 Ｃ．Ｉ．ビグメントレッド１８０（イソインドリノンレッド２ＢＬＴ等）の如きイソインドリノン顔料、 Ｃ．Ｉ．ビグメントレッド８３（マダーレーキ等）の如きアリザリンレーキ顔料等が挙げられる。
【００２６】
シアン色を呈する顔料として、Ｃ．Ｉピグメントブルー２５（ジアニシジンブルー等）の如きジスアゾ系顔料、 Ｃ．Ｉ．ビグメントブルー１５（フタロシアニンブルー等）の如きフタロシアニン顔料、 Ｃ．Ｉ．ビグメントブルー２４（ピーコックブルーレーキ等）の如き酸性染料レーキ顔料、 Ｃ．Ｉ．ビグメントブルー１（ビクロチアピュアブルーＢＯレーキ等）の如き塩基性染料レーキ顔料、 Ｃ．Ｉ．ビグメントブルー６０（インダントロンブルー等）の如きアントラキノン系顔料、 Ｃ．Ｉ．ビグメントブルー１８（アルカリブルーＶ−５：１）の如きアルカリブルー顔料等が挙げられる。
【００２７】
ブラック色を呈する顔料として、ＢＫ−１（アニリンブラック）の如きアニリンブラック系顔料等の有機顔料や酸化鉄顔料、及びファーネスブラック、ランプブラック、アセチレンブラック、チャンネルブラック等のカーボンブラック顔料類が挙げられる。
また、金、銀、銅などの色再現のために金属粉も使用可能である。
【００２８】
着色剤の表面処理方法としては、技術情報協会発行の「顔料分散技術」第５章に記載されている、ロジン処理、ポリマー処理、グラフト化処理、プラズマ処理等の方法が適用できる。
【００２９】
「ロジン処理」とは、顔料とロジンを機械的に混練し顔料表面にロジンを処理する方法や、顔料の水性スラリーにロジンのアルカリ水溶液を加えた後にアルカリ土類塩や酸などを加えてロジンの難溶性塩または遊離酸を顔料粒子表面に析出させる方法などである。ロジン処理では通常、顔料の数％から２０％程度のロジンが用いられ、▲１▼顔料の結晶成長防止効果により微細で透明性の大きな顔料が得られること、▲２▼粒子の乾燥凝集が弱くなるために機械的分散が容易になること、▲３▼顔料表面の親油性を増大させることにより油性ビヒクルに対するぬれを改善するなどに大きな効果があり、特に印刷インキの分野で多く使用されている。
【００３０】
「グラフト化処理」とは、カーボンブラック、およびシリカや酸化チタンなどの無機微粒子、さらには有機顔料などの表面に存在する水酸基やカルボキシル基やアミノ基などの官能基とポリマーとのグラフト化反応を行うものである。顔料表面へのポリマーのグラフト化反応には、（１）顔料微粒子の存在下で、重合開始剤を用いてビニルモノマーの重合を行い、系内で生成する生長ポリマーを顔料粒子表面の官能基で停止することによる方法、（２）顔料微粒子表面へ導入した重合開始基からグラフト鎖を生長させる方法、および（３）顔料微粒子表面の官能基とポリマー末端の官能基との高分子反応による方法等がある。
【００３１】
「プラズマ処理」とは、低温プラズマや熱プラズマにより顔料粉体表面の改質を行うものである。低温プラズマによる顔料表面の処理の具体例としては、（１）酸素や窒素などの非重合性気体のプラズマ照射による改質、（２）重合性気体を用いたプラズマ重合膜形成による改質、（３）プラズマ照射によって基材表面に活性種を形成させる１ｓｔ ｓｔａｇｅと、照射後モノマーと接触させ、あと反応でグラフト重合を進行させる２ｎｄ ｓｔａｇｅの２段階プロセスよりなるプラズマ開始グラフト重合反応による改質、などが挙げられる。
顔料の分散性を向上させると共に、この分散された着色成分微粒子をシード粒子として非水溶媒中で分散重合させる観点からは、以下に述べるポリマー処理が好ましい。
【００３２】
ポリマー処理の代表的方法としては、技術情報協会発行の「顔料分散技術」９９頁以降に記載のｉｎ−ｓｉｔｕ重合法を利用した化学的方法、相分離法（コアセルベーション）を利用した方法、顔料分散時に機械的な力で処理する方法などが挙げられる。
【００３３】
ｉｎ−ｓｉｔｕ重合法としては、顔料およびポリマーの系を分散した後懸濁重合する方法、分散剤の存在下に顔料を水系に分散し極性ポリマー、ビニル系ポリマー、多官能橋かけポリマーを加えて重合する方法、顔料を分散したモノマーを塊状重合した後懸濁重合または乳化重合することにより顔料への吸着が十分行えるようにする方法などがある。
【００３４】
相分離法（コアセルベーション）としては、ポリマー溶液中に顔料を分散させた後、何らかの方法でポリマーの溶解度を下げ溶液系からポリマーを顔料粒子上へ析出させる方法で化学的方法（ｉｎ−ｓｉｔｕ重合法）に比べ広い範囲のポリマーを選べる特徴がある。顔料を分散した樹脂溶液に非溶媒を加えて顔料表面に樹脂を析出させる方法や、水溶性ポリマーや水溶性樹脂溶液に顔料を微細に分散した後、ＰＨを調整してこれらを顔料表面に析出させる方法はロジン処理を含めて広く用いられている。酸可溶性の含窒素アクリル樹脂の酸溶液中で顔料を分散させた後、ｐＨを上げてポリマーを顔料表面で不溶化したものは塗料、印刷インキでの凝集防止、流動性、光沢、着色力向上に効果がみられている。
機械的な力でポリマー処理する方法を例示すると、ポリマーと顔料を予め顔料分が５〜９５％になる様に混合した後に、加熱しながらニーダー、三本ロールなどで混練し、ピンミル等で粉砕するものである。フラッシング樹脂処理という方法も機械的なポリマー処理方法に含まれる。
【００３５】
ポリマー処理に用いる樹脂としては、非水溶媒中で顔料の分散性を向上させると共に、この分散された着色成分微粒子をシード粒子として非水溶媒中で分散重合させる際の加熱分散安定性を付与するものであれば何でも良く、液体現像剤で従来使用されている樹脂も使用することができる。
【００３６】
好ましい樹脂としては、着色剤に吸着し、且つ非水系溶媒中に良く分散する機能を有するために、溶媒に溶媒和する部分と溶媒に溶媒和しにくい部分及び極性基を有する部分を持っている樹脂が好ましい。例えば、重合後に溶媒に溶媒和するモノマーとしては、ラウリルメタクリレート、ステアリルメタクリレート、２−エチルヘキシルメタクリレート、セチルメタクリレート等が挙げられる。重合後に溶媒に溶媒和しにくいモノマーとしては、メチルメタクリレート、エチルメタクリレート、イソプロピルメタクリレート、スチレン、ビニルトルエン等が挙げられる。極性基を含むモノマーとしては、アクリル酸、メタクリル酸、イタコン酸、フマル酸、マレイン酸、スチレンスルホン酸またはそのアルカリ塩などの酸性基モノマーと、ジメチルアミノエチルメタクリレート、ジエチルアミノエチルメタクリレート、ビニルピリジン、ビニルピロリジン、ビニルピペリジン、ビニルラクタムなどの塩基性基モノマーが挙げられる。
【００３７】
ポリマー処理に用いる樹脂の具体例としては、オレフィン重合体および共重合体（例えばポリエチレン、ポリプロピレン、ポリイソブチレン、エチレン−酢酸ビニル共重合体、エチレン−アクリレート共重合体、エチレン−メタクリレート共重合体、エチレン−メタクリル酸共重合体等）、スチレンおよびその誘導体の重合体ならびに共重合体（例えばブタジエン−スチレン共重合体、イソプレン−スチレン共重合体、スチレン−メタクリレート共重合体、スチレン−アクリレート共重合体等）、アクリル酸エステル重合体および共重合体、メタクリル酸エステル重合体および共重合体、イタコン酸ジエステル重合体および共重合体、無水マレイン酸共重合体、ロジン樹脂、水素添加ロジン樹脂、石油樹脂、水素添加石油樹脂、マレイン酸樹脂、テルペン樹脂、水素添加テルペン樹脂、クロマン−インデン樹脂、環化ゴム−メタクリル酸エステル共重合体、環化ゴム−アクリル酸エステル共重合体などが挙げられる。
【００３８】
本発明の着色材とポリマー処理に用いられる樹脂の割合は、着色剤／樹脂の質量比で９５／５〜５／９５の範囲で、好ましくは８０／２０〜１０／９０の範囲である。
【００３９】
更に表面処理された着色成分として、一般に市販されている加工顔料も用いることができる。市販加工顔料の具体例としては、チバスペシャリティケミカルズ社のマイクロリス顔料等が挙げられ、好ましい加工顔料の例としては、ロジンエステル樹脂で顔料を被覆したマイクロリス−Ｔ顔料が挙げられる。
【００４０】
本発明においては、上記表面処理された着色成分は、非水溶媒中に微粒子状に分散されて着色成分微粒子を得、これをシード粒子として更に分散重合させるものである。
まず、着色成分の分散工程について述べる。
該分散工程では、表面処理された着色成分を微粒子状に分散し且つ非水溶媒中で分散安定化させるために顔料分散剤の使用することが好ましい。
【００４１】
本発明に使用することができる、表面処理された着色成分を非水溶媒中で微粒子状に分散する顔料分散剤としては、該非水溶媒中で適用される一般の顔料用分散剤が使用できる。顔料用分散剤としては前記非極性の絶縁性溶媒に相溶し、安定的に顔料を微粒子分散できるものであれば良い。
【００４２】
顔料用分散剤の具体例としては、ソルビタン脂肪酸エステル（ソルビタンモノオレエート、ソルビタンモノラウレート、ソルビタンセスキオレエート、ソルビタントリオレエート等）、ポリオキシエチレンソルビタン脂肪酸エステル（ポリオキシエチレンソルビタンモノステアレート、ポリオキシエチレンソルビタンモノオレエート等）、ポリエチレングリコール脂肪酸エステル（ポリオキシエチレンモノステアレート、ポリエチレングリコールジイソステアレート等）、ポリオキシエチレンアルキルフェニルエーテル（ポリオキシエチレンノニルフェニルエーテル、ポリオキシエチレンオクチルフェニルエーテル等）、脂肪族ジエタノールアミド系などのノニオン系界面活性剤、及び高分子系分散剤としては、分子量１０００以上の高分子化合物が良く、例えば、スチレン−マレイン酸樹脂、スチレン−アクリル樹脂、ロジン、ＢＹＫ−１６０、１６２、１６４、１８２（ビックケミー社製のウレタン系高分子化合物）、ＥＦＫＡ−４７、ＬＰ−４０５０（ＥＦＫＡ社製のウレタン系分散剤）、ソルスパーズ２４０００（ゼネカ社製のポリエステル系高分子化合物）、ソルスパース１７０００（ゼネカ社の脂肪族ジエタノールアミド系）等が挙げられる。
【００４３】
高分子系顔料分散剤としては上記の他に更に、溶媒に溶媒和するラウリルメタクリレート、ステアリルメタクリレート、２−エチルヘキシルメタクリレート、セチルメタクリレート等のモノマーと、溶媒に溶媒和しにくいメチルメタクリレート、エチルメタクリレート、イソプロピルメタクリレート、スチレン、ビニルトルエン等のモノマー及び極性基を有する部分からなるランダム共重合体、あるいは特開平３−１８８４６９号公報に開示されているグラフト共重合体が挙げられる。上述の極性基を含むモノマーとしては、アクリル酸、メタクリル酸、イタコン酸、フマル酸、マレイン酸、スチレンスルホン酸またはそのアルカリ塩などの酸性基モノマーと、ジメチルアミノエチルメタクリレート、ジエチルアミノエチルメタクリレート、ビニルピリジン、ビニルピロリジン、ビニルピペリジン、ビニルラクタムなどの塩基性基モノマーが挙げられる。また、この他にはスチレン―ブタジエン共重合体、特開昭６０−１０２６３号公報に開示されているスチレンと長鎖アルキルメタクリレートのブロック共重合体等が挙げられる。好ましい顔料用分散剤としては、特開平３−１８８４６９号公報に開示されているグラフト共重合体等が挙げられる。
【００４４】
顔料用分散剤の使用量は、顔料１００質量部に対して、０．１〜３００質量部が好ましい。顔料分散剤の添加量を上記範囲内にすることで、充分な顔料分散効果を得ることが可能である。
【００４５】
表面処理された着色成分を、非水溶媒中に微粒子状に分散する分散工程において、顔料分散剤を使用する方法としては、例えば次のような方法があり、これらのいずれにによっても目的とする効果が得られる。
【００４６】
１．表面処理された着色成分と顔料分散剤を予め混合して得られる顔料組成物を非水系溶媒中に添加して分散する。
２．非水系溶媒に表面処理された着色成分と顔料分散剤を別々に添加して分散する。
３．非水系溶媒に表面処理された着色成分と顔料分散剤を予め別々に分散し、得られた分散体を混合する。この場合、顔料分散剤を溶剤のみで分散しても良い。
４．非水系溶媒に表面処理された着色成分を分散した後、得られた顔料分散体に顔料分散剤を 添加する等の方法があり、これらのいずれによっても目的とする効果が得られる。
【００４７】
上記の表面処理された着色剤（着色成分）を非水系溶媒中で混合あるいは分散させて、着色成分微粒子とすることができる。非水系溶媒中で混合あるいは分散する機械としては、ディゾルバー、ハイスピードミキサー、ホモミキサー、ニーダー、ボールミル、ロールミル、サンドミル、アトライター等が使用できる。この分散工程での表面処理された着色成分（加工顔料等）の分散平均粒径の範囲は０．０１〜１０μｍである。インク中の加工顔料の好ましい分散平均粒径範囲としては０．０１〜１．０μｍである。
【００４８】
次に上記分散された着色成分微粒子をシード粒子（シード）として、このシード粒子に一官能性単量体（Ｍ）を添加して分散重合させる工程について説明する。
非水溶媒中に着色成分を微粒子状に分散させシード粒子とした中で、一官能性単量体（Ｍ）と、重合体主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）を加えた重合系を、重合開始剤の存在下に重合させることにより、本発明の着色剤を内包した着色樹脂粒子が得られる。単量体（Ｍ）は、該非水溶媒に可溶であるが重合する事によって該非水溶媒に不溶性となる単量体であればいずれでもよい。
具体的には、例えば下記一般式（ＩＩ）で表される重合単量体が挙げられる。
【００４９】
【化５】

【００５０】
一般式（ＩＩ）中、Ｘ^２は−ＣＯＯ−、−ＯＣＯ−、−ＣＨ_２ＯＣＯ−、−ＣＨ_２ＣＯＯ−、−Ｏ−、−ＣＯＮＨＣＯＯ−、−ＣＯＮＨＯＣＯ−、−ＳＯ_２−、−ＣＯＮ（Ｚ^２）−、−ＳＯ_２Ｎ（Ｚ^２）−、またはフェニレン基（以下、フェニレン基を「−Ｐｈ−」と記載することもある。なお、フェニレン基は１，２−、１，３−および１，４−フエニレン基を包含する。）を表す。ここでＺ^２は、水素原子または炭素数１〜８の置換されていてもよい脂肪族基（たとえば、メチル基、エチル基、プロピル基、ブチル基、２−クロロエチル基、２−ブロモエチル基、２−シアノエチル基、２−ヒドロキシエチル基、ベンジル基、クロロベンジル基、メチルベンジル基、メトキシベンジル基、フェネチル基、３−フェニルプロピル基、ジメチルベンジル基、フロロベンジル基、２−メトキシエチル基、３−メトキシプロピル基等）を表す。
【００５１】
Ｙ^２は水素原子または炭素数１〜６の置換されてもよい脂肪族基（例えば、メチル基、エチル基、プロピル基、ブチル基、２−クロロエチル基、２，２−ジクロロエチル基、２，２，２−トリフロロエチル基、２−ブロモエチル基、２−ヒドロキシエチル基、２−ヒドロキシプロピル基、２，３−ジヒドロキシプロピル基、２−ヒドロキシ−３−クロロプロピル基、２−シアノエチル基、３−シアノプロピル基、２−ニトロエチル基、２−メトキシエチル基、２−メタンスルホニルエチル基、２−エトキシエチル基、３−ブロモプロピル基、４−ヒドロキシブチル基、２−フルフリルエチル基、２−チエニルエチル基、２−カルボキシエチル基、３−カルボキシプロピル基、４−カルボキシブチル基、２−カルボキシアミドエチル基、３−スルホアミドプロピル基、２−Ｎ−メチルカルボキシアミドエチル基、シクロペンチル基、クロロシクロヘキシル基、ジクロロヘキシル基等）を表す。
【００５２】
ｂ^１ およびｂ^２ は互いに同じでも異なっていてもよく、好ましくは水素原子、ハロゲン原子（例えば、塩素原子、臭素原子等）、シアノ基、炭素数１〜３のアルキル基（例えばメチル基、エチル基、プロピル基等）、−ＣＯＯ−Ｌ^１または−ＣＨ_２−ＣＯＯ−Ｌ^１〔ここでＬ^１は水素原子、または置換されてもよい炭素数１０以下の炭化水素基（例えば、アルキル基、アルケニル基、アラルキル基、アリール基等を表す）を表す。
【００５３】
具体的な単量体（Ｍ）としては、例えば炭素数１〜６の脂肪族カルボン酸（酢酸、プロピオン酸、酪酸、モノクロロ酢酸、トリフロロプロピオン酸等）のビニルエステル類あるいはアリルエステル類；アクリル酸、メタクリル酸、クロトン酸、イタコン酸、マレイン酸等の不飽和カルボン酸の炭素数１〜４の置換されてもよいアルキルエステル類またはアミド類（アルキル基として例えばメチル基、エチル基、プロピル基、ブチル基、２−クロロエチル基、２−ブロモエチル基、２−ヒドロキシエチル基、２−シアノエチル基、２−ニトロエチル基、２−メトキシエチル基、２−メタンスルホニルエチル基、２−ベンゼンスルホニルエチル基、２−カルボキシエチル基、４−カルボキシブチル基、３−クロロプロピル基、２−ヒドロキシ−３−クロロプロピル基、２−フルフリルエチル基、２−チエニルエチル基、２−カルボキシアミドエチル基等）；スチレン誘導体（例えば、スチレン、ビニルトルエン、α−メチルスチレン、ビニルナフタレン、クロロスチレン、ジクロロスチレン、ブロモスチレン、ビニルベンゼンカルボン酸、ビニルベンゼンスルホン酸、クロロメチルスチレン、ヒドロキシメチルスチレン、メトキシメチルスチレン、ビニルベンゼンカルボキシアミド、ビニルベンゼンスルホアミド等）；アクリル酸、メタクリル酸、クロトン酸、マレイン酸、イタコン酸等の不飽和カルボン酸；マレイン酸、イタコン酸の環状酸無水物；アクリロニトリル；メタクリロニトリル；重合性二重結合基含有のヘテロ環化合物（具体的には、例えば高分子学会編「高分子データハンドブック−基礎編−」、ｐ１７５〜１８４、培風舘（１９８６年刊）に記載の化合物、例えば、Ｎ−ビニルピリジン、Ｎ−ビニルイミダゾール、Ｎ−ビニルピロリドン、ビニルチオフェン、ビニルテトラヒドロフラン、ビニルオキサゾリン、ビニルチアゾール、Ｎ−ビニルモルホリン等）等が挙げられる。
単量体（Ｍ）は、上記の中から少なくとも一種以上選択されたモノマーを主成分とする。
【００５４】
更に、単量体（Ｍ）と共重合可能な、一般式 −Ｎ（Ｒ^１）（Ｒ^２）で示されるアミノ基を含有する、塩基性の単量体（Ｂ）を含有しても良い。Ｒ^１ 、Ｒ^２ は、各々同じでも異なってもよく、好ましくは水素原子又は炭素数１〜２２の置換されてもよいアルキル基（例えば、メチル基、エチル基、プロピル基、ブチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ドデシル基、トリデシル基、テトラデシル基、ヘキサデシル基、オクタデシル基、エイコシル基、ドコシル基、２−クロロエチル基、２−ブロモエチル基、２−シアノエチル基、２−メトキシカルボニルエチル基、２−メトキシエチル基、３−ブロモプロピル基等）、炭素数４〜１８の置換されてもよいアルケニル基（例えば、２−メチル−１−プロペニル基、２−ブテニル基、２−ペンテニル基、３−メチル−２−ペンテニル基、１−ペンテニル基、１−ヘキセニル基、２−ヘキセニル基、４−メチル−２−ヘキセニル基、デセニル基、ドデセニル基、トリデセニル基、ヘキサデセニル基、オクタデセニル基、リノレイル基等）、炭素数７〜１２の置換されてもよいアラルキル基（例えば、ベンジル基、フェネチル基、３−フェニルプロピル基、ナフチルメチル基、２−ナフチルエチル基、クロロベンジル基、ブロモベンジル基、メチルベンジル基、エチルベンジル基、メトキシベンジル基、ジメチルベンジル基、ジメトキシベンジル基等）、炭素数５〜８の置換されてもよい脂環式基（例えば、シクロヘキシル基、２−シクロヘキシルエチル基、２−シクロペンチルエチル基等）または炭素数６〜１２の置換されてもよい芳香族基（例えば、フェニル基、ナフチル基、トリル基、キシリル基、プロピルフェニル基、ブチルフェニル基、オクチルフェニル基、ドデシルフェニル基、メトキシフェニル基、エトキシフェニル基、ブトキシフェニル基、デシルオキシフェニル基、クロロフェニル基、ジクロロフェニル基、ブロモフェニル基、シアノフェニル基、アセチルフェニル基、メトキシカルボニルフェニル基、エトキシカルボニルフェニル基、ブトキシカルボニルフェニル基、アセトアミドフェニル基、プロピオアミドフェニル基、ドデシロイルアミドフェニル基等）が挙げられる。
【００５５】
また、Ｒ^１、Ｒ^２は環を形成しても良く、具体的には、ヘテロ原子（例えば酸素原子、窒素原子、イオウ原子等）を含有してもよい環形成の有機残基を表す。形成される環状アミノ基としては、例えばモルホリノ基、ピペリジノ基、ピリジニル基、イミダゾリル基、キノリル基、等が挙げられる。これらのアミノ基は、塩基性単量体の分子中に複数個含有されていてもよい。
本発明の着色樹脂粒子は、共重合成分としてアミノ基含有の塩基性単量体（Ｂ）を用いることで、粒子自身の表面が正荷電を発現し、非水系溶媒中に分散された粒子の分散安定性が向上する。これは粒子同志の近接時の荷電反発効果によるものと推測される。
塩基性単量体（Ｂ）は、単量体（Ｍ）の総量に対して、好ましくは１〜４５質量％、より好ましくは３〜３０質量％で用いる。
以下に、塩基性単量体（Ｂ）の具体例を示すが、本発明の範囲はこれに限定されるものではない。
【００５６】
【化６】

【００５７】
本発明では、単量体（Ｍ）と共重合可能な、−ＰＯ_３Ｈ_２基、−ＳＯ_３Ｈ基及び−ＳＯ_２Ｈ基から選ばれる少なくとも１つの酸性基を含有する酸性単量体（Ａ）を更に併用してもよい。酸性単量体（Ａ）は、分子中に複数個の上記酸性基を含有してもよい。本発明の着色樹脂粒子は、共重合成分として酸性単量体（Ａ）を用いることで、粒子自身の表面が負荷電に発現する事ができ、非水系溶媒中に分散された粒子の分散安定性が向上する。 酸性単量体（Ａ）は、単量体（Ｍ）の総量に対して、好ましくは１〜４５質量％、より好ましくは３〜３０質量％で用いる。
【００５８】
以下に、酸性単量体（Ａ）の具体例を示すが、本発明はこれらに限定されるものではない（但し下記具体例中、Ｙは−ＳＯ_３Ｈ基及び−ＳＯ_２Ｈ基又は−ＰＯ_３Ｈ_２又は−ＯＰＯ_３Ｈ_２基を表す）。
【００５９】
【化７】

【００６０】
【化８】

【００６１】
本発明では、単量体（Ｍ）と共重合可能な、長鎖の脂肪族基を有する単量体（Ｌ）を更に併用してもよい。長鎖の脂肪族基を有する単量体（Ｌ）において、長鎖の脂肪族基は炭素数７以上の脂肪族基を表す。その場合の具体例としては、総炭素数１０〜３２の脂肪族基（脂肪族基はハロゲン原子、ヒドロキシル基、アミノ基、アルコキシ基等の置換基を含有していてもよく、または酸素原子、イオウ原子、窒素原子等のヘテロ原子でその主鎖の炭素−炭素結合が介されてもよい）を有するアクリル酸、α−フルオロアクリル酸、α−クロロアクリル酸、α−シアノアクリル酸、メタクリル酸、クロトン酸、マレイン酸、イタコン酸の如き不飽和カルボン酸のエステル類（脂肪族基として、例えばデシル基、ドデシル基、トリデシル基、テトラデシル基、ヘキサデシル基、オクタデシル基、ドコシル基、ドデセニル基、ヘキサデセニル基、オレイル基、リノレイル基、ドコセニル基等が挙げられる）；上記不飽和カルボン酸のアミド類（脂肪族基として、上記エステル類で示したと同様のものが挙げられる）；高級脂肪酸のビニルエステル類あるいはアリルエステル類（高級脂肪酸として、例えば、ラウリン酸、ミリスチン酸、ステアリン酸、オレイン酸、リノール酸、べヘン酸等が挙げられる）；及び総炭素数８〜３２の脂肪族基が酸素原子に結合したビニルエーテル類（脂肪族基としては、上記の不飽和カルボン酸エステル類で例示した脂肪族基と同じものが挙げられる）等を挙げることができる。
【００６２】
長鎖の脂肪族基を有する単量体（Ｌ）を用いることにより、着色樹脂粒子の分散安定性、再分散性が更に向上する。これは単量体（Ｌ）に相当する共重合成分が、溶媒との親媒和性が高いことで粒子表面部分に配向し、そのことで粒子自身の表面の溶媒との親媒和性が高まり、粒子同士の凝集・沈殿を抑制するためと推定される。単量体（Ｌ）を用いる場合の使用量は、全単量体中、０．５〜２０質量％、好ましくは１〜１５質量％である。
【００６３】
次に分散安定化剤（Ｐ）について説明する。
分散安定化剤（Ｐ）は、下記一般式（Ｉ）で示される繰返し単位を含有する重合体で、且つ、その重合体主鎖の一部分が架橋された重合体で、該非水溶媒に可溶性である。
【００６４】
【化９】

【００６５】
一般式（Ｉ）中、Ｘ^１は−ＣＯＯ−、−ＯＣＯ−、−（ＣＨ_２）_ｋ−ＯＣＯ−、−（ＣＨ_２）_ｋ−ＣＯＯ−及び−Ｏ−から選ばれた１種或いはそれらの組み合わされた連結基を表わす。ｋは１〜３の整数を表す。
Ｙ^１は炭素数６〜３２の直鎖状或は分岐状のアルキル基又はアルケニル基を表す。具体的には、ブチル基、ヘプチル基、ヘキシル基、オクチル基、ドデシル基、トリデシル基、テトラデシル基、ヘキサデシル基、オクタデシル基、エイコサニル基、ヘキセニル基、オクテニル基、デセニル基、ドデセニル基、ヘキサデセニル基、オクタデセニル基、リノレル基等が挙げられる。
【００６６】
ａ^１とａ^２は、互いに同じでも異なってもよく、好ましくは水素原子、ハロゲン原子（例えば、塩素原子又は臭素原子等）、シアノ基、炭素数１〜３のアルキル基（例えば、メチル基、エチル基又はプロピル基等）、−ＣＯＯ−Ｚ^１又は炭化水素を介した−ＣＯＯ−Ｚ^１ （Ｚ^１は水素原子又は置換されてもよい炭化水素基を示す）を表す。Ｚ^１は水素原子又は炭素数１〜２２の、アルキル基、アルケニル基、アラルキル基、脂環式基、アリール基もしくは架橋環式炭化水素基を表わし、これらは置換されていてもよい。
【００６７】
Ｚ^１の好ましい炭化水素基としては、炭素数１〜２２の置換されてもよいアルキル基（例えば、メチル基、エチル基、プロピル基、ブチル基、ヘプチル基、ヘキシル基、オクチル基、ノニル基、デシル基、ドデシル基、トリデシル基、テトラデシル基、ヘキサデシル基、オクタデシル基、エイコサニル基、ドコサニル基、２−クロロエチル基、２−ブロモエチル基、２−シアノエチル基、２−メトキシカルボニルエチル基、２−メトキシエチル基、３−ブロモプロピル基等）、 炭素数４〜１８の置換されてもよいアルケニル基（例えば、２−メチル−１−プロペニル基、２−ブテニル基、２−ペンテニル基、３−メチル−２−ペンテニル基、１−ペンテニル基、１−ヘキセニル基，２−ヘキセニル基、４−メチル−２−ヘキセニル基、デセニル基、ドデセニル基、トリデセニル基、ヘキサデセニル基、オクタデセニル基、リノレル基等）、 炭素数７〜１２の置換されてもよいアラルキル基（例えば、ベンジル基、フェネチル基、３−フェニルプロピル基、ナフチルメチル基、２−ナフチルエチル基、クロロベンジル基、ブロモベンジル基、メチルベンジル基、エチルベンジル基、メトキシベンジル基、ジメチルベンジル基、ジメトキシベンジル基等）、 炭素数５〜８の置換されてもよい脂環式基（例えば、シクロヘキシル基、２−シクロヘキシルエチル基、２−シクロペンチルエチル基等）、及び炭素数６〜１２の置換されてもよい芳香族基（例えば、フェニル基、ナフチル基、トリル基、キシリル基、プロピルフェニル基、ブチルフェニル基、オクチルフェニル基、ドデシルフェニル基、メトキシフェニル基、エトキシフェニル基、ブトキシフェニル基、デシルオキシフェニル基、クロロフェニル基、ジクロロフェニル基、ブロモフェニル基、シアノフェニル基、アセチルフェニル基、メトキシカルボニルフェニル基、エトキシカルボニルフェニル基、ブトキシカルボニルフェニル基、アセトアミドフェニル基、プロピオアミドフェニル基、ドデシロイルアミドフェニル基等）、又は炭素数５〜１８の架橋環式炭化水素基（例えば、ビシクロ〔１，１，０〕ブタン、ビシクロ〔３，２，１〕オクタン、ビシクロ〔５，２，０〕ノナン、ビシクロ〔４，３，２〕ウンデカン、アダマンタン等の基）が挙げられる。
【００６８】
本発明の分散安定化剤（Ｐ）の重合体成分は、上記一般式（Ｉ）で示される繰返し単位の中から選択されるホモ重合体成分、もしくは一般式（Ｉ）で示される繰返し単位に相当する単量体と共重合し得る他の単量体とを重合して得られる共重合体成分を含有し、且つその重合体主鎖の一部分が架橋された重合体である。
共重合し得る他の単量体としては、重合性二重結合基を含有すればいずれでもよく、例えば、アクリル酸、メタクリル酸、クロトン酸、イタコン酸等の不飽和カルボン酸；炭素数６以下の不飽和カルボン酸のエステル誘導体もしくはアミド誘導体；カルボン酸類のビニルエステル類もしくはアリルエステル類；スチレン類；メタクリロニトリル；アクリロニトリル；重合性二重結合基含有の復素環化合吻等が挙げられる。より具体的には、前記した不溶化する単量体（Ｍ）と同一の内容の化合物等が挙げられる。
分散安定化剤（Ｐ）における重合体成分中、一般式（Ｉ）で示される繰返し単位の成分は、重合体全成分中、少なくとも３０質量％以上であり、好ましくは５０質量％以上、更に好ましくは７０質量％以上である。
【００６９】
重合体中に架橋構造を導入する方法としては、通常知られている方法を利用することができる。
即ち、▲１▼単量体の重合反応において、多官能性単量体を共存させて重合する方法、及び、▲２▼重合体中に、架橋反応を進行する官能基を含有させ高分子反応で架橋する方法である。
本発明の分散安定化剤（Ｂ）は、製造方法が簡便なこと（例えば、長時間の反応を要する、反応が定量的でない、反応促進助剤を用いる等で不純物が混入する等）等から、自己橋かけ反応を有する官能基；−ＣＯＮＨＣＨ_２ＯＲ^３（ここでＲ^３は水素原子又はアルキル基を示す）あるいは、重合による橋かけ反応が有効である。
重合反応において、好ましくは、重合性官能基を２個以上有する単量体を上記した一般式（Ｉ）で示される繰返し単位に相当する単量体とともに重合することで、ポリマー鎖間を橋架する方法である。重合性官能基として具体的には下記構造のものを挙げることができるが、上記の重合性官能基を２個以上有する単量体は、これらの重合性官能基を同一のものあるいは異なったものを２個以上有した単量体であればよい。
【００７０】
【化１０】

【００７１】
重合性官能基を２個以上存した単量体の具体例は、例えば同一の重合性官能基を有する単量体として、ジビニルベンゼン、トリビニルベンゼン等のスチレン誘導体；多価アルコール（例えばエチレングリコール、ジエチレングリコール、トリエチレングリコール、ボリエチレングリコール＃２００、＃４００、＃６００、１，３−ブチレングリコール、ネオペンチルグリコール、ジプロピレングリコール、ポリプロピレングリコール、トリメチロールブロパン、トリメチロールエタン、ペンタエリスリトールなど）又は、ボリヒドロキシフエノール（例えばヒドロキノン、レゾルシン、カテコールおよびそれらの誘導体）のメタクリル酸、アクリル酸又はクロトン酸のエステル類、ビニルテル類又はアリルエーテル類；二塩基酸（例えばマロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、マレイン酸、フタル酸、イタコン酸等）のビニルエステル類、アリルステル支頁、ビニルアミド頻又はアリルアミド頻；ポリアミン（例えばエチレンジアミン、１，３−プロピレンジアミン、１，４−ブチレンジアミン等）とビニル基を含有するカルボン酸（例えば、メタクリル酸、アクリル酸、クロトン酸、アリル酢酸等）との縮合体などが挙げられる。
【００７２】
又、異なる重合性官能基を有する単量体としては、例えば、ビニル基を含有するカルボン酸〔例えば、メタクリル酸、アクリル酸、メタクリロイル酢酸、アクリロイル酢酸、メタクリロイルプロピオン酸、アクリロイルプロピオン酸、イタコニロイル酢酸、イタコニロイルプロピオン酸、カルボン酸無水物とアルコール又はアミンの反応体（例えばアリルオキシカルボニルブロピオン酸、アリルオキシカルボニル酢酸、２−アリルオキシカルボニル安息香酸、アリルアミノカルボニルプロピオン酸等）等〕のビニル基を含有したエステル誘導体又はアミド誘導体（例えば、メタクリル酸ビニル、アクリル酸ビニル、イタコン酸ビニル、メタクリル酸アリル、アクリル酸アリル、イタコン酸アリル、メタクリロイル酢酸ビニル、メタクリロイルプロピオン酸ビニル、メタクリロイルプロピオン酸アリル、メタクリル酸ビニルオキシカルボニルメチルエステル、アクリル酸ビニルオキシカルボニルメチルオキシカルボニルエチレンエステル、Ｎ−アリルアクリルアミド、Ｎ−アリルメタクリルアミド、Ｎ−アリルイタコン酸アミド、メタクリロイルプロピオン酸アリルアミド等）；およびアミノアルコール類（例えばアミノエタノ一ル、１−アミノプロパノール、１−アミノブタノール、１−アミノヘキサノール、２−アミノブタノール等）と、ビニル基を含有したカルボン酸との縮合体などが挙げられる。
本発明に用いられる２個以上の重合性官能基を有する単量体は、全単量体の１０質量％以下、好ましくは８質量％以下用いて重合し、本発明の非水溶媒に可溶性である樹脂を形成する。
【００７３】
本発明の分散安定化剤（Ｐ）は、従来公知の合成方法によって容易に合成することができる。
即ち、一般式（Ｉ）で示される繰り返し単位に相当する単量体、及び上記した多官能性単量体を少なくとも共存させて、重合開始剤（例えば、アゾビス系化合物、過酸化物等）により重合する方法が簡便であり好ましい。
ここで用いられる重合開始剤は、各々全単量体１００質量部に対して０．５〜１５質量％であり、好ましくは１〜１０質量％である。以上の如くして製造された本発明の分散安定化剤（Ｐ）は、不溶性樹脂粒子と相互作用し、不溶性樹脂粒子に吸着する。分散安定化剤（Ｐ）の吸着した粒子は、非水溶媒に可溶となる分散安定化剤（Ｐ）が架橋されていることにより、非水溶媒への親和性が著しく向上される。このように不溶性樹脂粒子界面の親媒性が向上されていることに加えて、更に、粒子に吸着しないで非水溶媒中に存在する分散安定化剤（Ｐ）が分散安定化剤の吸着した粒子同士の接近を立体的に抑制しているものと推定される。これらのことにより不溶性粒子の凝集・沈殿が抑制され、再分散性が著しく向上するものと考えられる。
【００７４】
本発明の分散安定化剤（Ｐ）の重量平均分子量（Ｍｗ）は、５×１０^３〜１×１０^６が好ましく、より好ましくは２×１０^４〜３×１０^５である。
【００７５】
本発明で用いられる顔料を内包した着色樹脂粒子を製造するには、非水溶媒中に表面処理された着色成分を微粒子状に分散させシード粒子とした中で、単量体と重合体繰返し成分主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）を加えた重合系を、過酸化ベンゾイル、アゾビス（２，４−ジメチルバレロニトリル）、アゾビス（４−メトキシ−２，４−ジメチルバレロニトリル）、アゾビスイソブチロニトリル又はブチルリチウム等の重合開始剤の存在下に重合させればよい。
【００７６】
非水溶媒中に表面処理された着色成分を微粒子状に分散させシード粒子とした中に、単量体と重合体繰返し成分主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）と重合開始剤とを具体的に加えるには、
（１）単量体と分散安定化剤（Ｐ）と重合開始剤とを非水溶媒中に混合溶解した溶液を滴下する方法、もしくは一括あるいは分割して添加する方法、
（２）非水溶媒中に着色成分を微粒子状に分散させシード粒子とした中に分散安定化剤（Ｐ）を溶解した溶液を加え、次に単量体と重合開始剤とを滴下、もしくは一括あるいは分割して添加する方法、
（３）非水溶媒中に着色成分を微粒子状に分散させシード粒子とした中に、単量体、分散安定化剤（Ｐ）、重合開始剤を非水溶媒中に混合溶解した溶液の一部を加え分散重合させた後に、残りの単量体、分散安定化剤（Ｐ）、重合開始剤の混合物を任意に添加する方法、
（４）非水溶媒中に着色成分を微粒子状に分散させシード粒子とした中に単量体の一部を加えてシード粒子へのモノマー吸収を促進させ、次に残りの単量体、分散安定化剤（Ｐ）と重合開始剤とを滴下、もしくは一括あるいは分割して添加する方法等
があり、いずれの方法を用いても製造することができる。
【００７７】
次に顔料を内包した着色樹脂粒子を形成する各成分の量について説明する。シード粒子（着色成分微粒子）と単量体｛（Ｍ）並びに、必要に応じて（Ｂ）、（Ａ）及び／又は（Ｌ）｝の総量との使用割合は、５／９５〜９５／５質量比が好ましく、より好ましくは１０／９０〜８０／２０質量比である。単量体総量の仕込み量は、非水溶媒１００質量部に対して５〜８０質量部程度であり、好ましくは１０〜５０質量部である。可溶性もしくはコロイド状に分散している、重合体繰返し成分主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤（Ｐ）は、上記で用いる全単量体１００質量部に対して１〜１００質量部であり、好ましくは３〜５０質量部である。重合開始剤の量は、全単量体の０．１〜５モル％が適切である。又、重合温度は２０〜１８０℃程度であり、好ましくは３０〜１２０℃である。反応時間は１〜１５時間が好ましい。
【００７８】
反応に用いた非水溶媒中に、トルエン、キシレン等の芳香族炭化水素が残存する場合、及び前記したアルコール類、ケトン類、エーテル類、エステル類等の極性溶媒を併用した場合、あるいは重合造粒化される単量体の未反応物が残存する場合、該溶媒あるいは単量体の沸点以上に加温して留去するかあるいは減圧留去することによって除くことが好ましい。
【００７９】
以上の如くして製造された非水系顔料内包樹脂粒子は、顔料が均一に微粒子分散され、且つ分散液の分散安定性に優れることにより、ノズル部での目詰まりが起きない吐出安定性の高いインクジェットプリンタ用油性インクを提供する。また記録紙上での乾燥性、記録画像の耐水性、耐光性に優れており、且つ高度の耐擦過性を有する。更に、非水系溶媒中で均一に微粒子分散された顔料内包樹脂粒子を容易に得ることができ、荷電極性の制御、荷電の経時安定性に優れたインクジェットプリンタ用油性顔料インク、及びその安価な製造方法を提供する。また、単量体を適切に選択する事により、定着性、荷電性などの機能を顔料内包樹脂粒子に導入することができる特徴を有する。
【００８０】
以下の実施例で、本発明のインク組成物がインクジェットプリンタ用油性インクとして有用な事を示す。インクジェットプリンタとしては、ピエゾ方式及び静電方式のインクジェットプリンタを例にして説明するが、これらの方式に限定されずに、サーマル方式やＮＴＴなどのスリットジェットに代表されるインクジェットプリンタにも適用できる。
【００８１】
静電方式のインクジェットプリンタについて更に説明する。
図１及び図２は吐出ヘッドの例を説明する概略図で、図１はライン走査型マルチチャンネルインクジェットヘッドの構成を示す図で、記録ドットに対応した吐出電極の断面を示している。同図においてインク１００はポンプを含む循環機構１１１から、ヘッドブロック１０１に接続されたインク供給流路１１２を通して、ヘッド基板１０２と吐出電極基板１０３間に供給され、同じくヘッドブロック１０１に形成されたインク回収流路１１３を通してインク循環機構１１１に回収される。この吐出電極基板１０３は、貫通孔１０７を有する絶縁性基板１０４と、この貫通孔１０７の周囲で記録媒体側に形成されている吐出電極１０９とから構成されている。一方ヘッド基板１０２上には凸状インクガイド１０８が前記貫通孔１０７の略中心位置に配置されている。この凸状インクガイド１０８はプラスチック樹脂、セラミックスなど絶縁性部材からなり、前記貫通孔１０７と中心が等しくなるように同じ列間隔、ピッチで配置され、所定の方法でヘッド基板１０２上に保持されている。各凸状インクガイド１０８は厚みが一定の平板の先端を三角形あるいは台形状に切り出した形状で、その先端部がインク滴飛翔位置１１０となる。各凸状インクガイド１０８はその先端部からスリット状の溝を形成しても良く、そのスリットの毛細管現象により、インク飛翔位置１１０へのインク供給がスムースに行われ、記録周波数を向上することが出来る。またインクガイドの任意の表面は必要に応じて導電性を有していても良く、その場合には導電部分は電気的に浮遊状態とする事によって、吐出電極への少ない電圧印加で有効にインク飛翔位置に電界を形成できる。各凸状インクガイド１０８は、それぞれの貫通孔からほぼ垂直に所定の距離だけインク滴飛翔方向に突きだしている。凸状インクガイド１０８の先端に対向して記録紙である記録媒体１２１が配置され、この記録媒体１２１のヘッド基板１０２と反対側の背面に、記録媒体１２１を案内するプラテンの役割を兼ねる対向電極１２２が配置されている。また、ヘッド基板１０２と吐出電極基板１０３間によって形成される空間の底部には泳動電極１４０が形成されており、これに所定の電圧を印加する事により、インクガイドの吐出位置方向にインク中の荷電粒子を電気泳動させ、吐出の応答性を上げることが出来る。
【００８２】
次に、吐出電極基板１０３の具体的構成例について図２を用いて説明する。図２は、吐出電極基板１０３を記録媒体１２１側から見た図で、複数個の吐出電極が主走査方向に二列でアレイ状に配列されて、各吐出電極の中心に貫通孔１０７が形成され、この貫通孔１０７の周辺にはそれぞれ個別の吐出電極１０９が形成されている。本実施例では吐出電極１０９の内径は貫通孔１０７の径より一回り大きく設けられているが、貫通孔１０７の径と同径でも良い。ここでは、絶縁性基板１０４は２５から２００μｍ程度の厚さのポリイミドからなり、吐出電極１０９は１０から１００μｍ程度の厚さの銅箔からなり、貫通孔１０７の内径は１５０から２５０μｍΦ程度である。
【００８３】
次に、静電方式のインクジェット記録装置の記録動作を説明する。ここでは正荷電したインクを用いた場合を例にとって説明するが、本発明は本例に限定される物ではない。記録時には、インク循環機構１１１からインク供給流路１１２を経て供給されたインク１００は貫通孔１０７から凸状インクガイド１０８の先端のインク飛翔位置１１０に供給されると共に、一部はインク回収流路１１３を経てインク循環機構１１１に回収される。ここで、吐出電極１０９にはバイアス電圧源１２３から常時バイアスとして例えば＋１．５ｋＶの電圧が与えられ、これに信号電圧源１２４からの画像信号に応じた信号電圧として例えばＯＮ時に＋５００Ｖのパルス電圧が吐出電圧１０９に重畳される。またこの際、泳動電極１４０は＋１．８ｋＶの電圧が印加されている。一方、記録媒体１２１の背面に設けられた対向電極１２２は、図のように接地電圧０Ｖに設定されている。場合によっては記録媒体１２１側を例えば−１．５ｋＶに帯電させてバイアス電圧としても良い。この場合には、対向電極１２２表面に絶縁層を設け、記録媒体にコロナチャージャー、スコロトロンチャージャー、固体イオン発生器等により帯電を行い、かつ吐出電極１０９は例えば接地され、これに信号電圧源１２４からの画像信号に応じた信号電圧として例えばＯＮ時に＋５００Ｖのパルス電圧が吐出電圧１０９に重畳される。またこの際、泳動電極１４０は＋２００Ｖの電圧が印加される。今、吐出電圧１０９がＯＮ状態（５００Ｖが印加された状態）となり、バイアスＤＣ１．５ｋＶに５００Ｖのパルス電圧が重畳された合計２ｋＶの電圧が加わると、凸状電極１０８先端のインク滴飛翔位置１１０から、インク滴１１５が飛び出し、対向電極１２２方向に引っ張られて、該記録媒体１２１に向けて飛翔して画像を形成する。
【００８４】
なお、飛翔後のインク液滴の飛翔を精密制御し記録媒体上での着弾精度を向上するため、吐出電極と記録媒体間に中間電極を設ける、あるいは吐出電極間に電界干渉抑制用のガード電極を設ける、等の手段がしばしば講じられるが、本実施例においても必要により好適に使用されることはもちろんである。また、ヘッド基２８板１０２と吐出電極基板１０３間に多孔質体を設けても良く、この場合にはインクジェットヘッドの移動等によるインク内圧の変化の影響を防止できると共にインク滴吐出後の貫通孔１０７部へのインク液供給が迅速に達成される。したがって、インク滴１１５の飛翔が安定化され、記録媒体１２１上に濃度の安定した良好な画像を高速に記録することができる。
【００８５】
［実施例］
以下、本発明の実施例を説明する。
分散安定化剤の合成例１：分散安定化剤（Ｐ−１）
オクタデシルメタクリレート１００ｇ、ジビニルベンゼン２ｇ及びトルエン２００ｇの混合溶液を窒素気流下撹拌しながら温度８５℃に加温した。２，２’−アゾビスイソブチロニトリル（略称Ａ．Ｉ．Ｂ．Ｎ）３．０ｇを加え４時間反応し、更にＡ．Ｉ．Ｂ．Ｎを１．０ｇ加えて２時間反応し、更にＡ．Ｉ．Ｂ．Ｎを０．５ｇ加えて２時間反応した。冷却後メタノール１．５Ｌ中に、この混合溶液を再沈し、白色粉末を濾集後乾燥して、粉末８８ｇを得た。得られた重合体の重量平均分子量は３．３×１０^４であった。
【００８６】
分散安定化剤の合成例２〜１４：分散安定化剤（Ｐ−２）〜（Ｐ−１４）
合成例１において、オクタデシルメタクリレートの代りに下記表−Ａの単量体を用いる他は合成１と全く同様に操作して各分散安定化剤を合成した。各分散安定化剤の重量平均分子量は３．０×１０^４〜５．０×１０^４であった。
【００８７】
【表１】

【００８８】
分散安定化剤の合成例１５〜２７：分散安定化剤（Ｐ−１５）〜（Ｐ−２７）
合成例１において、架橋用多官能性単量体であるジビニルベンゼン２ｇの代わりに、下記表−Ｂの多官能性単量体又はオリゴマーを用いる他は、合成例と全く同様に操作して各分散安定化剤を合成した。各分散安定化剤の重量平均分子量は３．０×１０^４〜６．０×１０^４であった。
【００８９】
【表２】

【００９０】
分散安定化剤の合成例２８：分散安定化剤（Ｐ−２８）
オクタデシルメタクリレート９５ｇ、Ｎ−メトキシメチルアクリルアミド５ｇ、トルエン１５０ｇ及びイソブロパノール５０ｇの混合吻を窒素気流下に温度７５℃に加温した。Ａ．Ｉ．Ｂ．Ｎ．を３．０ｇ加え、８時間反応した。次に、Ｄｅａｎ−Ｓｔａｒｋを用いて、温度１１０℃に加温し６時間攪拌した。用いた溶媒イソプロパノール及び反応で副生するメタノールを除去した。冷却後、メタノール１．５Ｌ中に再沈し、白色粉末を濾集後、乾燥した。収量８２ｇで重量平均分子量は５．６×１０^４であった。
【００９１】
実施例１
＜顔料分散液の調製＞
下記構造の顔料分散剤（Ｄ−１）をアイソパーＨに加熱溶解して調液した２０％溶液を、顔料分散剤として用いた。上記顔料分散剤溶液８８．２５質量部と、黒色加工顔料としてロジンエステル樹脂で処理されたマイクロリスブラックＣ−Ｔ（チバ・スペシャリティ・ケミカルズ社製）１７．６５質量部、アイソパーＨ２９．４質量部及びガラスビーズ２５０質量部とともにペイントシェイカー（東洋精機ＫＫ）で３０分間混合した。次にガラスビーズをろ別した後、高速度分散混和機器ダイノミル（商品名；ＫＤＬ）で回転数３０００ｒｐｍで３時間分散した。メディアはガラスビーズＭＫ−３ＧＸを使用した。分散液中の顔料粒子の体積平均粒径を、超遠心式自動粒度分布測定装置ＣＡＰＡ７００（堀場製作所）にて測定した所、０．１６μｍと良好に分散されていた。
【００９２】
【化１１】

【００９３】
＜着色樹脂粒子の調製＞
ガラスビーズをろ過した加工顔料分散液のろ液（固形分２３．３％）８５．８ｇを四つ口フラスコに入れ窒素気流下攪拌しながら温度８０℃で３時間加熱した。次にこの加工顔料分散液中に、分散安定化剤（Ｐ）として（Ｐ−１）を粉体で８ｇ、メタクリル酸メチル１２．０ｇ、アクリル酸メチル２８．０ｇ及びアイソパーＨ１２０ｇの混合溶液に２，２′−アゾビス（２，４−ジメチルバレロニトリル）１．０ｇを加えた溶液をフィード溶液として、滴下速度２．５ｍｌ／分で滴下しその後３時間反応させた。滴下開始から約２０分して発熱が始まり、反応液温度は約５℃程上昇した。３時間反応後に温度を９０℃に上げ２時間攪拌し未反応のモノマーを留去した。冷却後２００メッシュのナイロン布を通し得られた黒色樹脂粒子分散液は重合率９７％でその体積平均粒子サイズは０．２４μｍであった。得られた黒色樹脂粒子分散液は、１カ月静置保存した後の分散状態も良好であった。
黒色樹脂粒子分散液をＳ−８００形電界放射形走査電子顕微鏡（日立電気社製）で観察した所、約１００ｎｍ程度のマイクロリスブラック顔料粒子が分散重合後には約１８０ｎｍの球形状樹脂粒子に成長しており、滴下モノマーがシード顔料粒子内で吸収され重合していることが判った。
更に黒色粒子分散液を透過形走査電子顕微鏡で観察した所、分散重合後の約１８０ｎｍの球形状着色樹脂粒子の中にはシードの顔料粒子が内包されているのが判った。
以上より、本発明のシード分散重合により生成した着色樹脂粒子は、ロジンエステル樹脂処理された顔料を内部に含有した着色樹脂粒子である事が判る。
【００９４】
＜インク組成物：（ＩＪ−１）の作製＞
上記着色樹脂粒子分散液を、溶媒留去により一旦濃縮しアイソパーＧにて希釈する事により、粘度は１３ｃｐ（Ｅ型粘度計、温度２５℃で測定）、表面張力は２３ｍＮ／ｍ（協和界面科学社製の自動表面張力計、温度２５℃で測定）のインク組成物（ＩＪ−１）を調液した。インクジェット記録装置としてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）を用い、上記インク組成物（ＩＪ−１）を充填して、富士写真フイルムインクジェットペーパーハイグレード専用紙上に描画した所、ノズル詰まりが無く安定に吐出した。得られた描画画像は、滲みがなく、画像濃度１．８の良質で明瞭なものであった。次にフルベタパターンを印字して、印字物を乾燥させた後ベタ部を指で擦ったところ、目視で地汚れが全くなく極めて耐擦過性に優れていることが判った。インク組成物は、長期に保存しても沈降凝集が見られず分散性が極めて良好で、かなりな期間連続して印刷に使用でき優れた鮮明度の印刷を与えた。
【００９５】
実施例２
＜顔料分散物の調製＞
黒色顔料としてカーボンブラック＃３０（三菱化学社製）１００質量部、ポリマー処理の樹脂としてエチレン／ステアリルアクリレート共重合体（９５／５モル比）、２００質量部をトリオブレンダーで予備粉砕しよく混合した後に、１２０℃に加熱した三本ロールミルで溶融混練（２０分）した。上記の顔料混練物をピンミルで粉砕した。
次に顔料混練物１０質量部、アイソパーＨ６５質量部、下記構造の顔料分散剤（Ｄ−２）をアイソパーＨに加熱溶解して調液した２０ｗｔ％溶液を２０質量部、及び３Ｇ−Ｘガラスビーズ２５０質量部とともにペイントシェイカー（東洋精機ＫＫ）で６０分間混合した。次にガラスビーズをろ別した後、高速度分散混和機器ダイノミル（商品名；ＫＤＬ）で回転数３０００ｒｐｍで３時間分散した。メディアはガラスビーズＭＫ−３ＧＸを使用した。分散液中の顔料粒子の体積平均粒径を、超遠心式自動粒度分布測定装置ＣＡＰＡ７００（堀場製作所）にて測定した所、０．１６μと良好に分散されていた。
【００９６】
【化１２】

【００９７】
＜着色樹脂粒子の調製＞
ガラスビーズをろ過した顔料分散液のろ液（固形分１４．０％）２１４．３ｇを四つ口フラスコに入れ窒素気流下攪拌しながら温度７５℃で１時間加熱した。次にこの顔料分散液中に、実施例１と同様に、分散安定化剤（Ｐ−２）を粉体で４ｇ、メタクリル酸メチル６．０ｇ、アクリル酸メチル１４．０ｇ、及びアイソパーＨ８０ｇの混合溶液に２，２′−アゾビス（２，４−ジメチルバレロニトリル）０．５ｇを加えた溶液をフィード溶液として、一時間で滴下しその後３時間反応させた。滴下開始から約１５分して発熱が始まり、反応液温度は約４℃程上昇した。３時間反応後に温度を９０℃に上げ窒素流量を上げながら、２時間攪拌し未反応のモノマーを留去した。黒色樹脂粒子分散液は重合率９６．０％でその体積平均粒子サイズは０．２２μｍであった。得られた黒色樹脂粒子分散液は、１カ月静置保存した後の分散状態も良好であった。
【００９８】
＜インク組成物：（ＩＪ−２）の作製＞
上記着色樹脂粒子分散液を、溶媒留去により一旦濃縮しアイソパーＧにて希釈する事により、粘度は１３ｃｐ、表面張力は２３ｍＮ／ｍのインク組成物（ＩＪ−２）を調製した。インク組成物（ＩＪ−２）を、実施例１と同様にしてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）で印刷した所、滲みのない良質の明瞭な印刷を与えた。また実施例１と同様にして耐擦過性を調べた所、目視で地汚れが全くなく極めて耐擦過性に優れていることが判った。インク組成物は、長期に保存しても沈降凝集が見られず分散性が良好であつた。
【００９９】
実施例３
＜顔料分散物の調製＞
黒色顔料としてカーボンブラック＃１００（三菱化学社製）１０質量部、水１００質量部をフラッシャーで攪拌後、ポリマー処理の樹脂としてスチレン／ビニルトルエン／ラウリルメタクリリレート共重合体（４０／５８／２モル比）の３３％トルエン溶液６０質量部を、更にフラッシャーに加え攪拌した。次いで、加熱し減圧して水分と溶媒を除去して含水率１質量％の黒色塊状物を得た。黒色塊状物を真空乾燥し、水分を完全に除去した後、サンプルミルで粉砕し、０．１−０．０１ｍｍの黒色粉体を得た。実施例２において、顔料混練物の代わりに上記黒色粉体を用い、顔料分散剤として（Ｄ−２）の代わりに下記構造の顔料分散剤（Ｄ−３）を用いた他は、実施例２と全く同様に顔料分散を行った。ガラスビーズをろ別した後得られた黒色顔料分散液は、体積平均粒径が０．１３μｍと分散性は良好であった。
【０１００】
【化１３】

【０１０１】
＜着色樹脂粒子の調製＞
ガラスビーズをろ過した顔料分散液のろ液（固形分１３．０％）をシード粒子として、実施例２において、分散安定化剤（Ｐ−２）の代わりに（Ｐ−３）を４ｇ用いた他は、実施例２と全く同様にして分散重合を行った。得られた黒色樹脂粒子分散液は重合率９８．０％でその体積平均粒子サイズは０．２３μｍであった。得られた黒色樹脂粒子分散液は、１カ月静置保存した後の分散状態も良好であった。
【０１０２】
＜インク組成物：（ＩＪ−３）の作製＞
上記顔料樹脂粒子分散液を、粘度は１３ｃｐ、表面張力は２３ｍＮ／ｍに調製してインク組成物（ＩＪ−３）を得た。インク組成物（ＩＪ−３）を、実施例１と同様にしてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）で印刷した所、滲みのない良質の明瞭な印刷を与えた。また実施例１と同様にして耐擦過性を調べた所、目視で地汚れが全くなく極めて耐擦過性に優れていることが判った。インク組成物は、長期に保存しても沈降凝集が見られず分散性が良好であつた。
【０１０３】
比較例１
＜比較用顔料分散液の調製＞
青色顔料としてアルカリブルー ５質量部、顔料分散剤としてラウリルメタクリレート／アクリル酸共重合体（組成比９５／５ｗｔ／ｗｔ）５質量部とを、アイソパーＨ９０質量部及びガラスビーズ２５０質量部とともにペイントシェイカー（東洋精機ＫＫ）で３０分間混合した。次にガラスビーズをろ別した後、高速度分散混和機器ダイノミル（商品名；ＫＤＬ）で回転数３０００ｒｐｍで３時間分散し分散液中の顔料粒子の体積平均粒径を、超遠心式自動粒度分布測定装置ＣＡＰＡ７００（堀場製作所）にて測定した所、０．１３μｍと良好に分散されていた。
【０１０４】
＜比較用着色樹脂粒子＞
ガラスビーズをろ過した顔料分散液のろ液（固形分９．６％）２０８．３ｇを四つ口フラスコに入れ窒素気流下攪拌しながら溶液温度を８０℃で３時間加熱した。次にこの顔料分散液中に、実施例１と同様に、分散安定化剤（Ｐ−１）を８ｇ、メタクリル酸メチル１２．０ｇ、アクリル酸メチル２８．０ｇ及びアイソパーＨ１２０ｇの混合溶液に２，２′−アゾビス（２，４−ジメチルバレロニトリル）１．０ｇを加えた溶液をフィード溶液として、滴下速度２．５ｍｌ／分で滴下しその後３時間反応させた。滴下開始から約１５分して発熱が始まり、反応液温度は約５℃程上昇したが、フラスコ壁面に粗大粒子が付着しており、反応後にはフラスコの底に多量の沈殿物がみられた。比較例１の着色樹脂粒子は、粗大粒子、沈降物の生成のため、次のインク組成物に供することができなかった。
【０１０５】
比較例２〜３
実施例１において、ロジンエステル樹脂処理された黒色顔料マイクロリスブラックＣ−Ｔ （チバ・スペシャリティ・ケミカルズ社製）の代わりに、下記のポリマーで処理された青色顔料（Ｃ．Ｉ．Ｐｉｇｍｅｔ Ｂｌｕｅ １５：３）を用いた他は実施例１と全く同様に顔料分散を行った。

【０１０６】
分散後にガラスビーズをろ別し得られた比較例２〜３の顔料分散液は、体積平均粒径が比較例２で１．４８μｍ、比較例３で１．６７μｍであった。比較例２〜３の顔料分散液は、粗大粒子があり経時で沈降物が生成するなど分散性は良好でないため、次のシード重合に供することができなかった。
【０１０７】
実施例１〜３と比較例１〜３より、本発明の如くポリマー処理された顔料は、特異的に微細粒子化され良好な分散安定性を有し、また、分散安定化剤として、重合体成分の主鎖の一部分が架橋された分散安定化剤を用いたために、シード分散重合が良好に進行し、そのシード分散重合により生成したポリマー処理された顔料を内部に含有する着色樹脂粒子は、明瞭な印刷画質、極めて優れた耐擦過性、良好な長期分散性等の、良好なインク特性を示すことが判った。
【０１０８】
実施例４
＜顔料分散液の調製＞
黒色顔料としてカーボンブラック＃３０（三菱化学社製）１００質量部、ポリマー処理の樹脂としてメチルメタクリレート／ステアリルメタクリレート共重合体（９／１モル比）、２００質量部をトリオブレンダーで予備粉砕しよく混合した後に、１２０℃に加熱した三本ロールミルで溶融混練（２０分）した。上記の顔料混練物をピンミルで粉砕した。
次に顔料混練物１０質量部、アイソパーＧ６５質量部、顔料分散剤としてソルプレン１２０５（旭化成社製、スチレン／ブタジエン共重合体）をアイソパーＧに加熱溶解して調液した２０ｗｔ％溶液を２５質量部、及び３Ｇ−Ｘガラスビーズ２５０質量部とともにペイントシェイカー（東洋精機ＫＫ）で６０分間混合した。次にガラスビーズをろ別した後、高速度分散混和機器ダイノミル（商品名；ＫＤＬ）で回転数３０００ｒｐｍで３時間分散した。メディアはガラスビーズＭＫ−３ＧＸを使用した。分散液中の顔料粒子の体積平均粒径を、超遠心式自動粒度分布測定装置ＣＡＰＡ７００（堀場製作所）にて測定した所、０．２１μｍと良好に分散されていた。
【０１０９】
＜着色樹脂粒子の調製＞
ガラスビーズをろ過した顔料分散液のろ液（固形分１４．０％）２１４．３ｇを四つ口フラスコに入れ窒素気流下攪拌しながら温度５０℃で１時間加熱した。次にこの顔料分散液中に、上記の分散安定化剤（Ｐ−２）を粉体で４ｇ、アクリル酸メチル２０．０ｇ及びアイソパーＨ８０ｇの混合溶液に２，２′−アゾビス（４−メトキシ−２，４−ジメチルバレロニトリル）０．７ｇを加えた溶液をフィード溶液として、一時間で滴下しその後３時間反応させた。滴下開始から約２０分して発熱が始まり、反応液温度は約５℃程上昇した。３時間反応後に温度を５０℃から８０℃に上げ窒素流量を上げながら、２時間攪拌し未反応のモノマーを留去した。冷却後２００メッシュのナイロン布を通し得られた黒色樹脂粒子分散液は重合率９２％でその体積平均粒子サイズは０．２４μｍであった。得られた黒色樹脂粒子分散液は、１カ月静置保存した後の分散状態も良好であった。
【０１１０】
＜インク組成物：（ＩＪ−４）の作製＞
上記着色樹脂粒子分散液を、溶媒留去により一旦濃縮しアイソパーＧにて希釈する事により、粘度は１３ｃｐ、表面張力は２３ｍＮ／ｍのインク組成物（ＩＪ−４）を調製した。インク組成物（ＩＪ−４）を、実施例１と同様にしてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）で印刷した所、滲みのない良質の明瞭な印刷を与えた。また実施例１と同様にして耐擦過性を調べた所、目視で地汚れが全くなく極めて耐擦過性に優れていることが判った。インク組成物は、長期に保存しても沈降凝集が見られず分散性が良好であつた。
【０１１１】
比較例４
＜比較用インク組成物：（ＩＪＲ−１）の作製＞
実施例４の着色樹脂粒子の代わりにシード粒子の顔料分散液を用いた他は、インク組成物（ＩＪ−４）と同様にして、比較用インク組成物（ＩＪＲ−１）を作成した。インクの粘度は１２ｃｐ、表面張力は２３ｄｙｎｅ／ｃｍであった。比較用インク組成物（ＩＪＲ−１）を、実施例１と同様にしてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）で印刷した所、滲みのない印刷を与えたものの、ベタ画像部を指で擦ると簡単に画像部が取れてしまい、耐擦過性が極めて悪い事が判った。更に、得られた印刷画像部を指で擦って取れないようにするには、印刷記録体を１２０℃以上に加熱定着する必要がある事が判った。
【０１１２】
本発明のインク組成物（ＩＪ−４）と比較用インク組成物（ＩＪＲ−１）の実験結果より、本発明の如くポリマー処理された顔料をシード粒子として、重合体成分の一部が架橋された分散安定化剤を用いたシード分散重合により、低軟化性の樹脂で被覆された着色樹脂粒子は、明瞭な印刷画質、良好な易定着性、極めて優れた耐擦過性、良好な長期分散性等の、良好なインク特性を示すことが判った。
【０１１３】
実施例５
＜顔料分散物の調製＞
実施例１において、黒色顔料マイクロリスブルーＣ−Ｔ （チバ・スペシャリティ・ケミカルズ社製）の代わりに、黄色顔料マイクロリスイェロ−３Ｒ−Ｔ （チバ・スペシャリティ・ケミカルズ社製）を用いた他は実施例１と全く同様に顔料分散を行った。ガラスビーズをろ別した後得られた黄色顔料の分散液は、体積平均粒径が０．２０μｍと分散性は良好であった。
【０１１４】
＜着色樹脂粒子の調製＞
黄色顔料の分散液（固形分２０．０％）１００ｇを四つ口フラスコに入れ窒素気流下攪拌しながら温度８０℃で２時間加熱した。実施例１において、分散安定化剤として（Ｐ−１）を粉体で４ｇ、メタクリル酸メチル６．０ｇ、アクリル酸メチル１２．０ｇ、ジメチルアミノエチルメタクリレート２．０ｇ及びアイソパーＨ８０ｇの混合溶液に２，２′−アゾビス（２，４−ジメチルバレロニトリル）０．６ｇを加えた溶液をフィード溶液として、滴下速度２．０ｍｌ／分で滴下し３時間反応させた他は、実施例１と全く同一の反応操作を行った。反応液温度は約４℃程上昇した。得られた黄色樹脂分散液は、重合率９５％、体積平均粒子サイズは０．２６μｍであり、１カ月静置保存した後の分散状態も良好であった。
【０１１５】
＜インク組成物：（ＩＪ−５）の作製＞
黄色樹脂粒子分散液をアイソパーＧで樹脂粒子成分が６．０％になる様希釈した。次いで荷電調節剤としてオクタデセン−半マレイン酸オクタデシルアミド共重合体を、０．０１ｇ／アイソパーＧ １リットルになる様添加してインク組成物（ＩＪ−５）を調液した。インク組成物（ＩＪ−５）の荷電量の測定を、特公昭６４−６９６号に記載の現像特性装置（印加電圧５００Ｖ、印加した電極の背面に誘起された電圧の時間変化の初期値を測定）で行った。インク組成物（ＩＪ−５）は全体荷電が２４０ｍＶ、黄色樹脂粒子の荷電が２０１ｍＶと明瞭な正荷電性を示し、一ヵ月後の荷電量の変化も殆ど無く極めて安定している事が判った。また、その荷電量は荷電調節剤の量により容易に制御できる事が判った。
【０１１６】
比較例５
＜比較用インク組成物：（ＩＪＲ−２）の作製＞
実施例５において、シード粒子である黄色顔料分散物をインク組成物（ＩＪ−５）と同様にインク化して比較用インク組成物（ＩＪＲ−２）を作成した。比較用インク組成物（ＩＪＲ−２）の荷電量を測定したところ、荷電極性は負荷電で、全体荷電が９０ｍＶ、黄色顔料粒子の荷電が１３ｍＶであった。
実施例５と比較例５より、シード粒子の黄色顔料マイクロリスイェロ−３Ｒ−Ｔ（比較用インク組成物（ＩＪＲ−２））の荷電極性はもともと負荷電であるが、重合体成分の主鎖の一部分が架橋された分散安定化剤を用いたシード分散重合により樹脂被覆した本発明の着色樹脂粒子（インク組成物（ＩＪ−５））は、荷電極性が明瞭な正荷電を示し、その荷電量も荷電調節剤の量により容易に制御できる事が判る。即ち、もともとの顔料の荷電極性に依らず、シード分散重合により顔料表面を樹脂被覆する事により、荷電極性（適切に荷電調節剤を選択して）、荷電量を自由に制御できることが判る。
【０１１７】
＜画像描画性＞
インクジェツト装置として、図−１に示すヘッド構造の１００ｄｐｉ ６４チャンネルの静電式インクジェツトヘッドを使用し、インク組成物（ＩＪ−５）をインクタンクに充填した。エアーポンプ吸引により記録媒体であるコート記録紙表面の埃除去を行った後、吐出ヘッドを描画位置までコート記録紙に近づけ、描画解像度６００ｄｐｉでインクを吐出し描画した。この際、パルス電圧を調節してドット径１５μｍから６０μｍの範囲で１６段階でドット面積を変化させながら描画した。描画画像は滲みのない満足し得る濃度の良質の明瞭な画像を与えた。インクヘッドからの吐出安定性も良好で、詰まりを生じる事が無く、画像描画でも安定したドット形状の印字ができた。また実施例１と同様にして耐擦過性を調べた所、目視で地汚れが全くなく極めて耐擦過性に優れていた。インク組成物（ＩＪ−５）は、長期に保存しても沈降凝集が見られず分散性が良好であった。
【０１１８】
一方、比較用インク組成物（ＩＪＲ−２）を用い、吐出ヘッドに印加するパルス電圧を負極性にして上記と同様に描画した所、描画画像は滲みがひどく画像濃度も低いものであった。また、吐出不良が発生したために、画像欠落が見られ満足する画像が得られなかった。
以上の結果より、本発明のシード分散重合により樹脂被覆した顔料樹脂粒子（インク組成物（ＩＪ−５））が、明瞭な正荷電と十分な荷電量も有するために、静電式インクジェツト装置において、明瞭な印刷画質、良好な吐出安定性、極めて優れた耐擦過性、良好な長期分散性等の、良好なインク特性を示すことが判った。
【０１１９】
実施例６〜１９
＜顔料分散液の調製＞
実施例１において、顔料分散剤（Ｄ−１）の代わりに（Ｄ−３）を加工顔料に対して５０ｗｔ％用い、また黒色加工顔料マイクロリスブラックＣ−Ｔの代わりに、青色加工顔料マイクロリスブルー４Ｇ−Ｔ（チバ・スペシャリティ・ケミカルズ社製）を用いた他は実施例１と全く同様に顔料分散を行った。ガラスビーズをろ別した後得られた顔料分散液は、体積平均粒径は０．１６μｍで分散性は良好であった。この青色顔料分散液を用いてシード分散重合を行い着色樹脂粒子、インク組成物（ＩＪ−６）〜（ＩＪ−１９）をそれぞれ作成した。
【０１２０】
＜着色樹脂粒子の調製＞
実施例１において、青色加工顔料分散液（固形分１９．１％）１５７．５ｇを用い、下記の表−Ｃに記載の分散安定化剤（Ｐ）を粉体で８ｇ、単量体を４０ｇ、アイソパーＧを１２０ｇ、２，２′−アゾビス（２，４−ジメチルバレロニトリル）を単量体の１モル％加えた溶液をフィード溶液と２時間で滴下して他は、実施例１と全く同一の反応操作を行った。反応液温度はそれぞれ約３〜８℃程上昇した。得られた青色粒子分散液６〜１９は、重合率が約８９〜９８％であり、その体積平均粒子サイズは０．２０〜０．２６μｍであった。また青色粒子分散液６〜１９は、１カ月静置保存した後の分散状態もそれぞれ良好であった。
【０１２１】
＜インク組成物：（ＩＪ−６）〜（ＩＪ−１９）＞
上記着色樹脂粒子分散液６〜１９を、それぞれ粘度は１２〜１４ｃｐ、表面張力は２２〜２４ｍＮ／ｍに調整してインク組成物（ＩＪ−６）〜（ＩＪ−１９）を得た。インク組成物（ＩＪ−６）〜（ＩＪ−１９）を、実施例１と同様にしてカラーファクシミリ彩遊記ＵＸ−Ｅ１ＣＬ（シャープ社製）で印刷した所、インク組成物（ＩＪ−６）〜（ＩＪ−１９）は、滲みのない満足し得る濃度の良質の明瞭な印刷を与え、また目視で地汚れが全くなく極めて耐擦過性に優れていた。また、インク組成物（ＩＪ−６）〜（ＩＪ−１９）は、長期に保存しても沈降凝集が見られず分散性が良好であつた。
【０１２２】
【表３】

【０１２３】
実施例２０
実施例５で得られたインク組成物（ＩＪ−５）を電子写真用液体現像剤として、リコー製湿式複写機ＤＴ−２５００を用いて印字テストしたところ、十分な画像濃度と良好な定着性を有する画像が得られた。また、この電子写真用液体現像剤は荷電の経時変化が極めて少なく、再分散性、保存安定性に優れるものであった。
【０１２４】
【発明の効果】
ポリマー処理された顔料をシード粒子として、非水溶媒中で重合体主鎖の一部分が架橋され該非水溶媒に可溶性の分散安定化剤を用いたシード分散重合により得られる、樹脂で被覆された本発明の顔料樹脂粒子を含有するインク組成物により、顔料が均一に微粒子分散され、且つ顔料分散液の分散安定性に優れるインクジェットプリンタ用油性インクを提供できる。また、ノズル部での目詰まりが起きない吐出安定性の高いインクジェットプリンタ用油性インクを提供できる。更に記録紙上での乾燥性、記録画像の耐水性、耐光性に優れており、且つ高度の耐擦過性を有するインクジェットプリンタ用油性インクを提供できる。また、分散安定性、耐擦過性に優れると共に、荷電極性の制御や荷電の経時安定性にも優れた静電方式インクジェツトプリンタ用油性インク、及び電子写真用液体現像剤を提供する事である。更に上記の特徴を有する、均一に微粒子分散された顔料を内包する樹脂粒子からなるインクジェットプリンタ用インクを得るための製造方法を提供できる。
【０１２５】
【図面の簡単な説明】
【図１】ライン走査型マルチチャンネルインクジェツトヘッドの構成例を示し、記録ドットに対応した 吐出電極の断面を示す図である。
【図２】吐出電極を記録媒体側から見た図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil-based ink for use in an ink jet recording apparatus for flying ink and forming characters and images on a transfer medium such as recording paper, and in particular, colored component particles in which colored resin particles are surface-treated with a colorant. Further, the present invention relates to an oil-based ink which is a colored resin particle coated with a polymer, an electrophotographic developer, and a method for producing the colored resin.
[0002]
[Prior art]
Various ink jet recording methods have been known. For example, Takeshi Yasui, “Real Color Hard Copy” Sangyo Tosho (published in 1993), Shin Ohno “Non-impact Printing -Technology and Materials”, CMC Co., Ltd. (1986), Takeshi Amari "Inkjet Printer-Technology and Materials", CMC Co., Ltd. (1998), etc. are described in the book, on-demand (voluntary injection) and continuous (continuous injection) methods is there. Further, there are known recording methods such as an electrostatic method (Sweet type, Hertz type) for the continuous type, and a piezoelectric method, a shear mode piezoelectric method, a thermal ink jet method, and an electrostatic acceleration type for the on-demand type.
The ink used in these ink jet recording methods is generally water-based ink because it is free from ink clogging in the ink discharge section and ink supply path, has excellent discharge stability, and has good color image quality such as color and gloss. Is used.
[0003]
Susumu Ichinose and Yuji Ohba as on-demand ink jet systems using electrostatic force, IEICE Transactions vol. J66-C (No. 1), p. 47 (1983), Tadayoshi Ohno, Mamoru Mizuguchi, Journal of the Institute of Image Electronics Engineers of Japan, Vol. 10, (No. 3), p. 157 (1981) or the like, and a method called electrostatic acceleration type ink jet or slit jet is known, and specific examples thereof include, for example, JP-A-56-170, JP-A-56-4467, and JP-A-57-151374. It is disclosed in each publication. This is because ink is supplied from an ink tank to a slit-shaped ink chamber in which a large number of electrodes are arranged on the inner surface of the slit-shaped ink holding portion, and a high voltage is selectively applied to these electrodes, thereby being close to the slit. Recording is performed by ejecting ink in the vicinity of the electrodes onto the opposing recording paper.
[0004]
Further, a concentration discharge type electrostatic system that does not use a slit-like recording head is disclosed in Japanese Patent Laid-Open No. 10-138493. The control electrode comprises a plurality of individual electrodes for applying an electrostatic force to the colorant component in the ink, an insulating substrate having a through hole, and a control electrode formed corresponding to the through hole. It is composed of a substrate and a convex ink guide arranged at the substantially central position of this through hole. The surface of this convex ink guide is transported to the ink droplet flying position by surface tension, and a predetermined voltage is applied to the control electrode. When applied, ink droplets are ejected onto the recording medium for recording.
[0005]
As inks used in such various ink jet recording methods, those in which various water-soluble dyes are dissolved in water or a solvent composed of water and a water-soluble organic solvent, and various additives are added as necessary are mainstream. (Hereinafter sometimes referred to as water-based dye ink). However, when actual printing is performed using water-based dye ink, the ink bleeds on the recording paper depending on the paper type, and high-quality printing cannot be obtained, and the formed recording image has poor water resistance and light resistance. In addition, there are drawbacks such as deterioration of the recorded image due to slow drying on the recording paper and tailing, and color mixing (color turbidity or unevenness at the color boundary when different color dots are printed adjacent to each other). It was.
Therefore, in order to improve the water resistance and light resistance of the recorded image, which is a problem of the water-based dye ink, an ink jet recording system using a pigment-based ink in which a pigment is dispersed as fine particles in an aqueous solvent or a non-aqueous solvent body. Various attempts have been made to apply this method.
For example, as an ink for an ink jet printer in which a pigment is dispersed in a solvent containing water as a main component, JP-A-2-255875, JP-A-3-76767, JP-A-3-76768, and JP-A-56-147871. JP-A 56-147868 proposes inks, but since the pigment is insoluble in the medium, the dispersion stability is generally poor, and the nozzle portion is likely to be clogged. Had a problem.
[0006]
On the other hand, an ink in which a pigment is dispersed in a non-polar insulating solvent (hereinafter sometimes referred to as an oil-based pigment ink) has less blotting because of its good absorbability to paper, and the water resistance of a recorded image is low. For example, inks such as Japanese Patent Application Laid-Open Nos. 57-10660 and 57-10661 have been proposed.
JP-A 57-10660 discloses finely divided pigments using an alcohol amide dispersant and JP-A 57-10661 uses a sorbitan-based dispersant. However, the pigment particles are used as a nonpolar insulating solvent. It was not sufficient to uniformly disperse the fine particles, and the dispersion stability was poor, so that there were still problems such as the nozzle part being easily clogged. Furthermore, since the pigment itself does not have a fixing ability with respect to the recording paper, it has a great drawback that it has poor scratch resistance.
In order to improve these, resin-soluble oil-based inks have been proposed in which a resin soluble in a nonpolar insulating solvent is used as a fixing agent and a pigment dispersant. For example, Japanese Patent Laid-Open No. 3-234772 proposes a terpene phenol resin as the above resin. However, the dispersion stability of the pigment is still insufficient, and there is a problem in the reliability as an ink. Further, since the resin is dissolved in a nonpolar solvent, there is no resin left to completely fix the pigment on the recording paper, and the water resistance and scratch resistance are not sufficient.
[0007]
On the other hand, in order to obtain a high degree of scratch resistance, it has been proposed to coat pigment particles with a resin that is insoluble or semi-soluble in a nonpolar insulating solvent. For example, Patent Document 1 (Japanese Patent Laid-Open No. 4-25574) proposes an oil-based ink in which a pigment is coated with a resin by a microcapsule method or the like. However, with this technique, it is difficult to uniformly disperse the pigment-encapsulated resin particles, and the dispersion stability is not sufficient.
In recent years, high-quality photographic quality has been achieved with general inkjet printers that use water-based dye inks, and pigment inks have been made as fine as possible to increase color development and transparency, and the dispersion state has been reduced. It has been required to keep it stable.
However, on the other hand, as the pigment becomes finer, the primary particles of the pigment are crushed simultaneously with the miniaturization of the pigment, and further, the aggregation energy increases simultaneously with the increase of the surface energy, so reaggregation easily occurs. Eventually, there is a problem that the storage stability of the finely divided pigment dispersion is impaired.
As described above, the demand for pigment dispersions used in oil-based pigment inks for ink jet printers requires a higher degree of fineness. It is very difficult to improve the properties, and no oil-based pigment ink satisfying all of the above has been known so far.
[0008]
When these oil-based pigment inks are used in electrostatic ink jet printers or electrophotographic liquid developers, control of the charge polarity and stability over time of the charge are required, but the polarity of the pigment surface is controlled. Since it is very difficult to achieve this, no oil-based pigment ink satisfying the above has been known so far.
A liquid developer for electrophotography using a non-aqueous solvent is generally a mixture comprising an aliphatic hydrocarbon solvent, a colorant, a fixing resin, a dispersant, and various additives added as necessary. Is pulverized with a ball mill or an attritor. Various proposals have been made for the production method thereof. For example, Patent Document 2 (Japanese Patent Laid-Open No. Sho 631-174070) discloses a method of polymerizing styrene, acrylic monomers, etc. in a non-aqueous solvent. A colored liquid developer is disclosed in which a polymer latex obtained is dyed with a dye and used as a colorant. However, this method using a dye as a colorant has the disadvantages that it is difficult to produce a black liquid developer, and that the dye system is low in image density and photobleaching. On the other hand, as an example of using a pigment as a coloring material, Patent Document 3 (Japanese Patent Publication No. Sho 62-3859) describes a pigment as a liquid developer for electrophotography and a natural resin-modified thermosetting resin as a fixing resin. Resins reacted in chain alkyl group-containing monomers have been proposed. However, although this technique is effective in improving the dispersion stability of the colorant, it has not yet had sufficient dispersion stability.
As described above, in an electrophotographic liquid developer using a pigment as a coloring material, sufficient dispersion stability as well as scratch resistance has been desired. Furthermore, since the charge polarity of the pigment differs depending on the type, it is desired that the charge polarity of the pigment particles is clarified and that the charge does not change with time.
[0009]
[Patent Document 1]
JP-A-4-25574
[Patent Document 2]
JP 63-174070 A
[Patent Document 3]
Japanese Examined Patent Publication No. 62-3859
[0010]
[Problems to be solved by the invention]
Accordingly, a first object of the present invention is to provide an oil-based ink jet printer with high ejection stability that does not cause clogging in the nozzle portion because the pigment is uniformly dispersed in fine particles and the dispersion stability of the pigment dispersion is excellent. To provide ink.
A second object of the present invention is to provide an oil-based ink for an ink jet printer which is excellent in drying properties on recording paper, water resistance and light resistance of recorded images, and has a high degree of scratch resistance.
The third object of the present invention is to provide an oil-based ink for an electrostatic ink jet printer, which is excellent in dispersion stability and scratch resistance, as well as charge polarity control and charge aging stability, and electrophotographic liquid development. It is to provide an agent.
A fourth object of the present invention is to provide a production method for obtaining an ink for an ink jet printer having the above-described characteristics and comprising resin particles enclosing a pigment dispersed uniformly in fine particles.
[0011]
[Means for Solving the Problems]
It has been found that the above-described problems of the present invention are solved by the following configuration.
(1) In a non-aqueous solvent having a relative dielectric constant of 1.5 to 20 and a surface tension of 15 to 60 mN / m (at 25 ° C.), a colored component obtained by surface-treating a colorant is dispersed in the form of fine particles in the non-aqueous solvent. And a polymer containing at least one monofunctional monomer (M) and a repeating unit represented by the following general formula (1) using the coloring component fine particles obtained as a seed particle, It is characterized in that it contains colored resin particles obtained by adding a dispersion stabilizer (P) that is partially crosslinked and soluble in the non-aqueous solvent, and dispersing and polymerizing in the presence of a polymerization initiator. An oil-based ink composition for an inkjet printer.
[0012]
[Formula 4]

[0013]
In general formula (I), X ¹ Is —COO—, —OCO—, — (CH ₂ ) _k -OCO-,-(CH ₂ ) _k It represents one or a combination of linking groups selected from —COO— and —O—. k represents an integer of 1 to 3. a ¹ And a ² May be the same or different from each other, and each represents a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, —COO—Z. ¹ Or -COO-Z via hydrocarbon ¹ (Z ¹ Represents a hydrogen atom or an optionally substituted hydrocarbon group. Y ¹ Represents an aliphatic group having 6 to 32 carbon atoms.
[0014]
(2) The inkjet printer according to (1), wherein the colorant is at least one pigment selected from organic pigments and inorganic pigments, and the color component is surface-treated by coating the colorant with a polymer. Oil-based ink composition.
(3) The oil-based ink composition for inkjet printers according to (1), wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant. .
[0015]
(4) Volume resistivity 10 ⁹ At least a monofunctional monomer (M) is obtained using, as seed particles, colored component fine particles obtained by dispersing a colored component obtained by surface-treating a colorant in a non-aqueous solvent of Ωcm or more into fine particles in the non-aqueous solvent. And at least one dispersion stabilizer (P) which is a polymer containing a repeating unit represented by the above general formula (I) and is partially crosslinked with the polymer main chain and soluble in the non-aqueous solvent; A liquid developer for electrophotography characterized by containing colored resin particles obtained by subjecting a dispersion added with a dispersion polymerization in the presence of a polymerization initiator.
[0016]
(5) The liquid development for electrophotography according to the above (4), which is at least one pigment selected from organic pigments and inorganic pigments, and the coloring component is surface-treated by coating the colorant with a polymer. Agent.
(6) The electrophotographic liquid developer according to (4) above, wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant.
[0017]
(7) In a non-aqueous solvent having a relative dielectric constant of 1.5 to 20 and a surface tension of 15 to 60 mN / m (at 25 ° C.), a coloring component obtained by surface-treating the colorant is dispersed in the form of fine particles in the non-aqueous solvent. And a polymer containing at least one monofunctional monomer (M) and a repeating unit represented by the above general formula (I) using the coloring component fine particles obtained as a seed particle, A process for producing colored resin particles obtained by subjecting a dispersion obtained by adding at least one dispersion stabilizer (P) having a partially crosslinked chain and soluble in the non-aqueous solvent to dispersion polymerization in the presence of a polymerization initiator .
(8) The colored resin particle according to claim 7, wherein the colorant is at least one pigment selected from an organic pigment and an inorganic pigment, and the coloring component is surface-treated by coating the colorant with a polymer. Production method.
(9) The method for producing colored resin particles according to (7), wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The non-aqueous solvent (dispersion medium) used in the oil-based ink composition for ink jet printers of the present invention is a nonpolar insulating solvent, having a relative dielectric constant of 1.5 to 20 and a surface tension of 15 to 60 mN / m (25 (In ° C). Further, the non-aqueous solvent used for the electrophotographic liquid developer has a volume resistivity of 10 ⁹ It is preferable that it is Ωcm or more. Further desirable properties are low toxicity, low flammability, and low odor.
[0019]
Examples of such a non-aqueous solvent include a solvent selected from linear or branched aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, petroleum naphtha, and halogen-substituted products thereof. For example, hexane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, Isopar E from Exxon, Isopar G, Isopar H, Isopar L, Saltol from Philippe Petroleum, IP Solvent from Idemitsu Petrochemical, Petroleum Naphtha Then, S. of Shell Petrochemical Co., Ltd. B. R. Solvents selected from Shellzol 70, Cielzol 71, Mobil Petroleum Company's Vegazole and the like can be used alone or in combination.
[0020]
Preferable hydrocarbon solvents include high-purity isoparaffinic hydrocarbons having a boiling point in the range of 150 to 350 ° C., and commercially available products such as Isopar G, H, L, M, and V (manufactured by Exxon Chemical Co., Ltd.) Name), Noper 12, 13, 15 (trade name), IP Solvent 1620, 2028 (trade name) manufactured by Idemitsu Petrochemical, Isosol 300,400 (trade name) manufactured by Nippon Petrochemical, Amsco OMS, Amsco 460 solvent ( Amsco; a brand name of Spirits).
These products are highly saturated aliphatic saturated hydrocarbons, the viscosity at 25 ° C. is 3 cSt or less, the surface tension at 25 ° C. is 22.5 to 28.0 mN / m, and the specific resistance at 25 ° C. is 10 ¹⁰ Ω · cm or more. In addition, it is characterized by low reactivity and stability, low toxicity, high safety, and low odor.
Examples of halogen-substituted hydrocarbon solvents include fluorocarbon solvents such as C ₇ F ₁₆ , C ₈ F ₁₈ C such as _n F _{2n + 2} Perfluoroalkanes represented by (Sumitomo 3M “Fluorinert PF5080”, “Fluorinert PF5070” (trade name), etc.), fluorine-based inert liquid (Sumitomo 3M “Fluorinert FC series” (trade name), etc.) , Fluorocarbons ("Crytox GPL series" (trade name) manufactured by DuPont Japan Limited), chlorofluorocarbons ("HCFC-141b" (trade name) manufactured by Daikin Industries, Ltd.), [F (CF ₂ ) ₄ CH ₂ CH ₂ I], [F (CF ₂ ) ₆ I] and the like (“I-1420”, “I-1600” (trade name), etc., manufactured by Daikin Fine Chemical Laboratory) and the like.
[0021]
As the non-aqueous solvent used in the present invention, higher fatty acid esters and silicone oils can also be used. Specific examples of silicone oil include low-viscosity synthetic dimethylpolysiloxane, and commercially available products include KF96L (trade name) manufactured by Shin-Etsu Silicone, SH200 (trade name) manufactured by Toray Dow Corning Silicone, and the like. .
The silicone oil is not limited to these specific examples. These dimethylpolysiloxanes are available in a very wide viscosity range depending on the molecular weight, but it is preferable to use those in the range of 1 to 20 cSt. These dimethylpolysiloxanes, like isoparaffinic hydrocarbons, are 10 ¹⁰ It has a volume resistivity of Ω · cm or more, and has characteristics such as high stability, high safety, and odorlessness. These dimethylpolysiloxanes are characterized by low surface tension and have a surface tension of 18 to 21 mN / m.
[0022]
Solvents that can be used in combination with the above organic solvents include alcohols (eg, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, fluorinated alcohol), ketones (eg, acetone, methyl ethyl ketone, cyclohexanone, etc.), carvone Acid esters (eg, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, etc.), ethers (eg, diethyl ether, dipropyl ether, tetrahydrofuran, dioxane, etc.) and halogenated hydrocarbons ( Examples thereof include methylene dichloride, chloroform, carbon tetrachloride, dichloroethane, methyl chloroform, and the like.
[0023]
Next, the surface-treated coloring component of the present invention will be described in detail.
The surface-treated coloring component of the present invention (hereinafter sometimes simply referred to as “coloring component”) is a surface-treated colorant, and the colorant is not particularly limited and is generally commercially available. All organic and inorganic pigments mentioned are mentioned.
[0024]
For example, C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. Monoazo pigments such as CI Pigment Yellow 74; I. Pigment yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as CI Pigment Yellow 17; I. Non-benzidine azo pigments such as CI Pigment Yellow 180; I. An azo lake pigment such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as CI Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).
[0025]
As a magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as CI Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment red 53: 1 (such as lake red C) and C.I. I. Pigment red 57: 1 (brilliant carmine 6B), an azo lake pigment such as C.I. I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G ′ Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (such as Thioindigo Bordeaux); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Quinacridone pigments such as C.I. Pigment Red 122 (quinacridone magenta, etc.); I. Pigment Red 180 (isoindolinone red 2BLT, etc.), isoindolinone pigments such as C.I. I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).
[0026]
As a pigment exhibiting a cyan color, C.I. Disazo pigments such as CI Pigment Blue 25 (dianisidine blue, etc.); I. Phthalocyanine pigments such as CI Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).
[0027]
Examples of pigments exhibiting a black color include organic pigments such as aniline black pigments such as BK-1 (aniline black), iron oxide pigments, and carbon black pigments such as furnace black, lamp black, acetylene black, and channel black. .
Also, metal powder can be used for color reproduction of gold, silver, copper and the like.
[0028]
As the surface treatment method of the colorant, methods such as rosin treatment, polymer treatment, grafting treatment, and plasma treatment described in Chapter 5 of “Pigment Dispersion Technology” published by the Technical Information Association can be applied.
[0029]
“Rosin treatment” refers to a method of mechanically kneading the pigment and rosin to treat the rosin on the pigment surface, or adding an alkaline aqueous solution of rosin to the pigment aqueous slurry and then adding an alkaline earth salt or acid to the rosin. For example, a method of precipitating a slightly soluble salt or a free acid on the pigment particle surface. In the rosin treatment, a rosin of about several to 20% of the pigment is usually used. (1) A fine and highly transparent pigment can be obtained by the effect of preventing the crystal growth of the pigment, and (2) the dry aggregation of the particles is weak. Therefore, mechanical dispersion becomes easy, and (3) it has a great effect in improving the wettability to the oil-based vehicle by increasing the lipophilicity of the pigment surface, and it is often used especially in the field of printing ink. .
[0030]
“Grafting treatment” refers to the grafting reaction between carbon black and inorganic fine particles such as silica and titanium oxide, as well as functional groups such as hydroxyl groups, carboxyl groups and amino groups present on the surface of organic pigments and polymers. Is what you do. In the grafting reaction of the polymer on the pigment surface, (1) the vinyl monomer is polymerized using a polymerization initiator in the presence of the pigment fine particles, and the growth polymer produced in the system is converted into functional groups on the pigment particle surface. A method by stopping, (2) a method of growing a graft chain from a polymerization initiating group introduced to the surface of the pigment fine particle, and (3) a method by a polymer reaction between the functional group on the surface of the pigment fine particle and the functional group at the end of the polymer. There is.
[0031]
“Plasma treatment” is a modification of the pigment powder surface by low-temperature plasma or thermal plasma. Specific examples of the treatment of the pigment surface with low-temperature plasma include (1) modification by plasma irradiation of non-polymerizable gas such as oxygen and nitrogen, (2) modification by plasma-polymerized film formation using polymerizable gas, ( 3) Modification by a plasma-initiated graft polymerization reaction consisting of a two-stage process of 1st stage for forming active species on the substrate surface by plasma irradiation and 2nd stage for contacting the post-irradiation monomer and post-reacting graft polymerization; Etc.
From the viewpoint of improving the dispersibility of the pigment and performing dispersion polymerization in a non-aqueous solvent using the dispersed colored component fine particles as seed particles, the polymer treatment described below is preferable.
[0032]
As a typical method of polymer treatment, a chemical method using an in-situ polymerization method described in “Pigment Dispersion Technology” on page 99 and later published by the Technical Information Association, a method using a phase separation method (coacervation), The method of processing with a mechanical force at the time of pigment dispersion etc. is mentioned.
[0033]
As an in-situ polymerization method, a method in which a pigment and a polymer system are dispersed and then suspension polymerization is performed, a pigment is dispersed in an aqueous system in the presence of a dispersant, and a polar polymer, a vinyl polymer, and a polyfunctional crosslinking polymer are added. There are a polymerization method, a method in which a monomer in which a pigment is dispersed is bulk polymerized, and then suspension polymerization or emulsion polymerization is performed to sufficiently adsorb the pigment.
[0034]
The phase separation method (coacervation) is a chemical method (in-situ method) in which a pigment is dispersed in a polymer solution, and then the solubility of the polymer is lowered by some method to precipitate the polymer from the solution system onto the pigment particles. Compared with the polymerization method), there is a feature that a wide range of polymers can be selected. Add a non-solvent to the pigment-dispersed resin solution to deposit the resin on the pigment surface, or finely disperse the pigment in the water-soluble polymer or water-soluble resin solution, then adjust the pH to deposit them on the pigment surface This method is widely used including rosin treatment. After dispersing the pigment in an acid solution of acid-soluble nitrogen-containing acrylic resin, increasing the pH to insolubilize the polymer on the pigment surface will prevent aggregation in paints and printing inks, improve fluidity, gloss, and coloring power. The effect is seen.
Exemplifying the method of polymer processing by mechanical force, after mixing the polymer and pigment in advance so that the pigment content is 5 to 95%, knead with a kneader, three rolls, etc. while heating and pulverize with a pin mill etc. To do. A method called a flushing resin treatment is also included in the mechanical polymer treatment method.
[0035]
As a resin used for polymer treatment, the dispersibility of the pigment is improved in a non-aqueous solvent, and heat dispersion stability is imparted when the dispersed colored component fine particles are used as seed particles for dispersion polymerization in a non-aqueous solvent. Any resin can be used as long as it is a liquid developer.
[0036]
Preferred resins have a function of adsorbing to a colorant and being well dispersed in a non-aqueous solvent, and therefore have a part that solvates with a solvent, a part that does not easily solvate with a solvent, and a part that has a polar group. Resins are preferred. For example, examples of the monomer that solvates with a solvent after polymerization include lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cetyl methacrylate. Examples of monomers that are difficult to solvate with the solvent after polymerization include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, styrene, and vinyl toluene. Monomers containing polar groups include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, styrene sulfonic acid or alkali salts thereof, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyl pyridine, vinyl Examples include basic group monomers such as pyrrolidine, vinylpiperidine, and vinyllactam.
[0037]
Specific examples of the resin used for polymer treatment include olefin polymers and copolymers (for example, polyethylene, polypropylene, polyisobutylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer, ethylene -Methacrylic acid copolymer, etc.), polymers of styrene and its derivatives and copolymers (eg butadiene-styrene copolymer, isoprene-styrene copolymer, styrene-methacrylate copolymer, styrene-acrylate copolymer, etc.) ), Acrylate polymers and copolymers, methacrylate polymers and copolymers, itaconic acid diester polymers and copolymers, maleic anhydride copolymers, rosin resins, hydrogenated rosin resins, petroleum resins, Hydrogenated petroleum resin, maleic acid tree , Terpene resins, hydrogenated terpene resins, chroman - indene resins, cyclized rubber - methacrylic acid ester copolymers, cyclized rubber - like acrylic acid ester copolymer.
[0038]
The ratio of the colorant of the present invention to the resin used for polymer treatment is in the range of 95/5 to 5/95, preferably in the range of 80/20 to 10/90, by the mass ratio of the colorant / resin.
[0039]
In addition, commercially available processed pigments can also be used as the surface-treated coloring component. Specific examples of commercially available processed pigments include microlith pigments manufactured by Ciba Specialty Chemicals, and preferred examples of processed pigments include Microlith-T pigments in which the pigment is coated with a rosin ester resin.
[0040]
In the present invention, the surface-treated colored component is dispersed in the form of fine particles in a non-aqueous solvent to obtain colored component fine particles, which are further dispersed and polymerized as seed particles.
First, the coloring component dispersion step will be described.
In the dispersion step, it is preferable to use a pigment dispersant in order to disperse the surface-treated colored component into fine particles and stabilize the dispersion in a non-aqueous solvent.
[0041]
As the pigment dispersant that can be used in the present invention and in which the surface-treated colored component is dispersed in the form of fine particles in a non-aqueous solvent, a general pigment dispersant applied in the non-aqueous solvent can be used. Any pigment dispersant may be used as long as it is compatible with the nonpolar insulating solvent and can stably disperse the pigment in fine particles.
[0042]
Specific examples of the dispersant for the pigment include sorbitan fatty acid esters (sorbitan monooleate, sorbitan monolaurate, sorbitan sesquioleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (polyoxyethylene sorbitan monostearate, Polyoxyethylene sorbitan monooleate), polyethylene glycol fatty acid ester (polyoxyethylene monostearate, polyethylene glycol diisostearate, etc.), polyoxyethylene alkylphenyl ether (polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl) Ethers), nonionic surfactants such as aliphatic diethanolamides, and polymer dispersants are polymers having a molecular weight of 1000 or more. The compound is good, for example, styrene-maleic acid resin, styrene-acrylic resin, rosin, BYK-160, 162, 164, 182 (urethane polymer compound manufactured by BYK Chemie), EFKA-47, LP-4050 (EFKA) Urethane dispersants manufactured by the company), Solsperz 24000 (polyester polymer compound manufactured by Zeneca), Solsperse 17000 (aliphatic diethanolamide from Zeneca), and the like.
[0043]
In addition to the above, the polymeric pigment dispersants include monomers such as lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cetyl methacrylate that are solvated in a solvent, and methyl methacrylate, ethyl methacrylate, and isopropyl that are difficult to solvate in a solvent. Examples thereof include random copolymers composed of monomers having a polar group and monomers such as methacrylate, styrene and vinyltoluene, and graft copolymers disclosed in JP-A-3-188469. Examples of the monomer containing the polar group include acidic group monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, styrene sulfonic acid, and alkali salts thereof, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and vinylpyridine. And basic group monomers such as vinylpyrrolidine, vinylpiperidine, and vinyllactam. Other examples include styrene-butadiene copolymers and block copolymers of styrene and long-chain alkyl methacrylate disclosed in JP-A-60-10263. Preferred examples of the dispersant for pigment include a graft copolymer disclosed in JP-A-3-188469.
[0044]
The amount of the pigment dispersant used is preferably 0.1 to 300 parts by mass with respect to 100 parts by mass of the pigment. By making the addition amount of the pigment dispersant within the above range, a sufficient pigment dispersion effect can be obtained.
[0045]
In the dispersion step of dispersing the surface-treated coloring component in the form of fine particles in a non-aqueous solvent, examples of the method of using the pigment dispersant include the following methods. An effect is obtained.
[0046]
1. A pigment composition obtained by previously mixing the surface-treated coloring component and the pigment dispersant is added and dispersed in a non-aqueous solvent.
2. A coloring component surface-treated in a non-aqueous solvent and a pigment dispersant are separately added and dispersed.
3. The coloring component surface-treated in the non-aqueous solvent and the pigment dispersant are separately dispersed in advance, and the obtained dispersion is mixed. In this case, the pigment dispersant may be dispersed only with a solvent.
4). There is a method of dispersing a colored component surface-treated in a non-aqueous solvent and then adding a pigment dispersant to the obtained pigment dispersion, and any of these methods can achieve the intended effect.
[0047]
The surface-treated colorant (coloring component) can be mixed or dispersed in a non-aqueous solvent to form colored component fine particles. As a machine for mixing or dispersing in a non-aqueous solvent, a dissolver, a high speed mixer, a homomixer, a kneader, a ball mill, a roll mill, a sand mill, an attritor or the like can be used. The range of the dispersion average particle diameter of the surface-treated colored component (processed pigment or the like) in this dispersion step is 0.01 to 10 μm. A preferable dispersion average particle diameter range of the processed pigment in the ink is 0.01 to 1.0 μm.
[0048]
Next, the step of dispersing and polymerizing the dispersed colored component fine particles as seed particles (seed) by adding a monofunctional monomer (M) to the seed particles will be described.
Dispersion stabilizer in which monofunctional monomer (M) and part of the polymer main chain are cross-linked and soluble in the non-aqueous solvent in which coloring components are dispersed in the form of fine particles in a non-aqueous solvent to form seed particles By polymerizing the polymerization system to which (P) has been added in the presence of a polymerization initiator, colored resin particles encapsulating the colorant of the present invention can be obtained. The monomer (M) may be any monomer that is soluble in the non-aqueous solvent but becomes insoluble in the non-aqueous solvent by polymerization.
Specifically, for example, a polymerization monomer represented by the following general formula (II) can be mentioned.
[0049]
[Chemical formula 5]

[0050]
In general formula (II), X ² Is —COO—, —OCO—, —CH ₂ OCO-, -CH ₂ COO-, -O-, -CONHCOO-, -CONHOCO-, -SO ₂ -, -CON (Z ² )-, -SO ₂ N (Z ² )-Or a phenylene group (hereinafter, the phenylene group may be described as "-Ph-". The phenylene group includes 1,2-, 1,3- and 1,4-phenylene groups). Represents. Where Z ² Is a hydrogen atom or an optionally substituted aliphatic group having 1 to 8 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2-bromoethyl group, 2-cyanoethyl group, 2-hydroxyethyl group, benzyl group, chlorobenzyl group, methylbenzyl group, methoxybenzyl group, phenethyl group, 3-phenylpropyl group, dimethylbenzyl group, fluorobenzyl group, 2-methoxyethyl group, 3-methoxypropyl group, etc. ).
[0051]
Y ² Is a hydrogen atom or an optionally substituted aliphatic group having 1 to 6 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2,2-dichloroethyl group, 2,2, 2-trifluoroethyl group, 2-bromoethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2,3-dihydroxypropyl group, 2-hydroxy-3-chloropropyl group, 2-cyanoethyl group, 3-cyano Propyl group, 2-nitroethyl group, 2-methoxyethyl group, 2-methanesulfonylethyl group, 2-ethoxyethyl group, 3-bromopropyl group, 4-hydroxybutyl group, 2-furfurylethyl group, 2-thienylethyl Group, 2-carboxyethyl group, 3-carboxypropyl group, 4-carboxybutyl group, 2-carboxyamidoethyl group, 3-sulfo Midopuropiru group, 2-N- methyl-carboxamide ethyl group, cyclopentyl group, chlorocyclohexyl group, a dichlorohexyl group).
[0052]
b ¹ And b ² May be the same or different from each other, preferably a hydrogen atom, a halogen atom (eg, chlorine atom, bromine atom, etc.), a cyano group, an alkyl group having 1 to 3 carbon atoms (eg, methyl group, ethyl group, propyl group, etc.) ), -COO-L ¹ Or -CH ₂ -COO-L ¹ [L here ¹ Represents a hydrogen atom or an optionally substituted hydrocarbon group having 10 or less carbon atoms (for example, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, etc.).
[0053]
Specific examples of the monomer (M) include vinyl esters or allyl esters of aliphatic carboxylic acids having 1 to 6 carbon atoms (acetic acid, propionic acid, butyric acid, monochloroacetic acid, trifluoropropionic acid, etc.); acrylic C1-C4 substituted alkyl esters or amides of unsaturated carboxylic acids such as acids, methacrylic acid, crotonic acid, itaconic acid, maleic acid (alkyl groups such as methyl, ethyl, propyl) Butyl group, 2-chloroethyl group, 2-bromoethyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 2-nitroethyl group, 2-methoxyethyl group, 2-methanesulfonylethyl group, 2-benzenesulfonylethyl group, 2-carboxyethyl group, 4-carboxybutyl group, 3-chloropropyl group, 2-hydroxy-3 Chloropropyl group, 2-furfurylethyl group, 2-thienylethyl group, 2-carboxyamidoethyl group, etc.); styrene derivatives (for example, styrene, vinyltoluene, α-methylstyrene, vinylnaphthalene, chlorostyrene, dichlorostyrene, Bromostyrene, vinylbenzenecarboxylic acid, vinylbenzenesulfonic acid, chloromethylstyrene, hydroxymethylstyrene, methoxymethylstyrene, vinylbenzenecarboxamide, vinylbenzenesulfoamide, etc.); acrylic acid, methacrylic acid, crotonic acid, maleic acid, itacone Unsaturated carboxylic acids such as acids; cyclic acid anhydrides of maleic acid and itaconic acid; acrylonitrile; methacrylonitrile; a heterocyclic compound containing a polymerizable double bond group (specifically, for example, “Polymer” Data Nd book-Basic edition ", p. 175-184, compounds described in Yabu Fu (1986), for example, N-vinyl pyridine, N-vinyl imidazole, N-vinyl pyrrolidone, vinyl thiophene, vinyl tetrahydrofuran, vinyl oxazoline, vinyl Thiazole, N-vinylmorpholine, etc.).
The monomer (M) contains as a main component at least one monomer selected from the above.
[0054]
Furthermore, the general formula —N (R), which is copolymerizable with the monomer (M). ¹ ) (R ² A basic monomer (B) containing an amino group represented by R ¹ , R ² Each may be the same or different, preferably a hydrogen atom or an optionally substituted alkyl group having 1 to 22 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, hexyl group, heptyl group, octyl group) Group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, docosyl group, 2-chloroethyl group, 2-bromoethyl group, 2-cyanoethyl group, 2-methoxycarbonylethyl group 2-methoxyethyl group, 3-bromopropyl group, etc.), an alkenyl group having 4 to 18 carbon atoms which may be substituted (for example, 2-methyl-1-propenyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-2-pentenyl group, 1-pentenyl group, 1-hexenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group Nyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linoleyl group, etc.), an aralkyl group having 7 to 12 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3-phenylpropyl group) Naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.), substituted with 5 to 8 carbon atoms May be an alicyclic group (for example, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, etc.) or an aromatic group having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group, tolyl). Group, xylyl group, propylphenyl group, butylphenyl group, octylpheny Group, dodecylphenyl group, methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group, decyloxyphenyl group, chlorophenyl group, dichlorophenyl group, bromophenyl group, cyanophenyl group, acetylphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group , Butoxycarbonylphenyl group, acetamidophenyl group, propioamidophenyl group, dodeciloylamidophenyl group, etc.).
[0055]
R ¹ , R ² May form a ring, and specifically represents a ring-forming organic residue that may contain a hetero atom (for example, an oxygen atom, a nitrogen atom, a sulfur atom, etc.). Examples of the cyclic amino group to be formed include morpholino group, piperidino group, pyridinyl group, imidazolyl group, quinolyl group and the like. A plurality of these amino groups may be contained in the basic monomer molecule.
The colored resin particles of the present invention are particles of particles dispersed in a non-aqueous solvent by using an amino group-containing basic monomer (B) as a copolymerization component so that the surface of the particles themselves is positively charged. Dispersion stability is improved. This is presumably due to the charge repulsion effect when the particles are close to each other.
The basic monomer (B) is preferably used in an amount of 1 to 45 mass%, more preferably 3 to 30 mass%, based on the total amount of the monomer (M).
Specific examples of the basic monomer (B) are shown below, but the scope of the present invention is not limited thereto.
[0056]
[Chemical 6]

[0057]
In the present invention, -PO copolymerizable with the monomer (M). ₃ H ₂ Group, -SO ₃ H group and -SO ₂ An acidic monomer (A) containing at least one acidic group selected from H groups may be further used in combination. The acidic monomer (A) may contain a plurality of the acidic groups in the molecule. By using the acidic monomer (A) as a copolymerization component, the colored resin particles of the present invention can develop the surface of the particles themselves as negatively charged, and the dispersion stability of the particles dispersed in a non-aqueous solvent. Improve. The acidic monomer (A) is preferably used in an amount of 1 to 45 mass%, more preferably 3 to 30 mass%, based on the total amount of the monomer (M).
[0058]
Specific examples of the acidic monomer (A) are shown below, but the present invention is not limited thereto (however, in the following specific examples, Y represents —SO ₃ H group and -SO ₂ H group or -PO ₃ H ₂ Or -OPO ₃ H ₂ Represents a group).
[0059]
[Chemical 7]

[0060]
[Chemical 8]

[0061]
In the present invention, a monomer (L) having a long-chain aliphatic group that can be copolymerized with the monomer (M) may be further used in combination. In the monomer (L) having a long-chain aliphatic group, the long-chain aliphatic group represents an aliphatic group having 7 or more carbon atoms. Specific examples in that case include an aliphatic group having 10 to 32 carbon atoms in total (the aliphatic group may contain a substituent such as a halogen atom, a hydroxyl group, an amino group, an alkoxy group, or an oxygen atom, Acrylic acid, α-fluoroacrylic acid, α-chloroacrylic acid, α-cyanoacrylic acid, methacrylic acid having a hetero atom such as a sulfur atom or a nitrogen atom, and a carbon-carbon bond of the main chain thereof may be interposed , Esters of unsaturated carboxylic acids such as crotonic acid, maleic acid, itaconic acid (eg aliphatic groups such as decyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl, docosyl, dodecenyl, hexadecenyl Groups, oleyl groups, linoleyl groups, dococenyl groups, etc.); amides of the above unsaturated carboxylic acids (as aliphatic groups) Examples of the higher fatty acid vinyl esters or allyl esters (higher fatty acids such as lauric acid, myristic acid, stearic acid, oleic acid, linoleic acid, behenic acid, etc.) And vinyl ethers in which an aliphatic group having 8 to 32 carbon atoms is bonded to an oxygen atom (the aliphatic group is the same as the aliphatic group exemplified in the above unsaturated carboxylic acid esters) And the like.
[0062]
By using the monomer (L) having a long-chain aliphatic group, the dispersion stability and redispersibility of the colored resin particles are further improved. This is because the copolymer component corresponding to the monomer (L) is oriented to the particle surface part due to its high solvophilicity with the solvent, and thus the solvophilicity with the solvent on the surface of the particle itself. This is presumed to increase and suppress aggregation / precipitation of particles. The usage-amount in the case of using a monomer (L) is 0.5-20 mass% in all the monomers, Preferably it is 1-15 mass%.
[0063]
Next, the dispersion stabilizer (P) will be described.
The dispersion stabilizer (P) is a polymer containing a repeating unit represented by the following general formula (I) and a polymer in which a part of the polymer main chain is crosslinked, and is soluble in the non-aqueous solvent. is there.
[0064]
[Chemical 9]

[0065]
In general formula (I), X ¹ Is —COO—, —OCO—, — (CH ₂ ) _k -OCO-,-(CH ₂ ) _k It represents one or a combination of linking groups selected from —COO— and —O—. k represents an integer of 1 to 3.
Y ¹ Represents a linear or branched alkyl or alkenyl group having 6 to 32 carbon atoms. Specifically, butyl group, heptyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, hexenyl group, octenyl group, decenyl group, dodecenyl group, hexadecenyl group, An octadecenyl group, a linolel group, etc. are mentioned.
[0066]
a ¹ And a ² May be the same as or different from each other, preferably a hydrogen atom, a halogen atom (for example, a chlorine atom or a bromine atom), a cyano group, an alkyl group having 1 to 3 carbon atoms (for example, a methyl group, an ethyl group, or a propyl group) Etc.), -COO-Z ¹ Or -COO-Z via hydrocarbon ¹ (Z ¹ Represents a hydrogen atom or an optionally substituted hydrocarbon group. Z ¹ Represents a hydrogen atom or an alkyl group, alkenyl group, aralkyl group, alicyclic group, aryl group or bridged cyclic hydrocarbon group having 1 to 22 carbon atoms, which may be substituted.
[0067]
Z ¹ The preferred hydrocarbon group is an alkyl group having 1 to 22 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, octyl group, nonyl group, decyl group). , Dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, 2-chloroethyl group, 2-bromoethyl group, 2-cyanoethyl group, 2-methoxycarbonylethyl group, 2-methoxyethyl group, 3-bromopropyl group, etc.), an alkenyl group having 4 to 18 carbon atoms which may be substituted (for example, 2-methyl-1-propenyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-2-pentenyl) Group, 1-pentenyl group, 1-hexenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group, decenyl group , Dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolel group, etc.), an aralkyl group having 7 to 12 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.), C5-C8 optionally substituted alicyclic Groups (for example, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, etc.) and optionally substituted aromatic groups having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group, tolyl group, xylyl group) Propylphenyl group, butylphenyl group, octylphenyl group, dodecylpheny Group, methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group, decyloxyphenyl group, chlorophenyl group, dichlorophenyl group, bromophenyl group, cyanophenyl group, acetylphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group, butoxycarbonylphenyl Group, acetamidophenyl group, propioamidophenyl group, dodecyloylamidophenyl group, etc.) or a bridged cyclic hydrocarbon group having 5 to 18 carbon atoms (for example, bicyclo [1,1,0] butane, bicyclo [3 , 2,1] octane, bicyclo [5,2,0] nonane, bicyclo [4,3,2] undecane, adamantane and the like.
[0068]
The polymer component of the dispersion stabilizer (P) of the present invention is a homopolymer component selected from the repeating units represented by the general formula (I) or the repeating unit represented by the general formula (I). It is a polymer containing a copolymer component obtained by polymerizing another monomer that can be copolymerized with the corresponding monomer, and having a part of the polymer main chain crosslinked.
Any other monomer that can be copolymerized may be used as long as it contains a polymerizable double bond group. Examples thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid; And ester derivatives or amide derivatives of unsaturated carboxylic acids; vinyl esters or allylic esters of carboxylic acids; styrenes; methacrylonitrile; acrylonitrile; More specifically, a compound having the same content as the monomer (M) to be insolubilized is mentioned.
In the polymer component in the dispersion stabilizer (P), the component of the repeating unit represented by the general formula (I) is at least 30% by mass, preferably 50% by mass or more, more preferably, in all the polymer components. Is 70% by mass or more.
[0069]
As a method for introducing a crosslinked structure into a polymer, a generally known method can be used.
That is, (1) in the polymerization reaction of the monomer, a method of polymerizing in the presence of a polyfunctional monomer, and (2) a polymer reaction in which the polymer contains a functional group that proceeds with a crosslinking reaction. It is a method of cross-linking with.
The dispersion stabilizer (B) of the present invention has a simple production method (for example, a long reaction time is required, the reaction is not quantitative, impurities are mixed by using a reaction accelerator, etc.), etc. , A functional group having a self-crosslinking reaction; -CONHCH ₂ OR ³ (Where R ³ Represents a hydrogen atom or an alkyl group) or a crosslinking reaction by polymerization is effective.
In the polymerization reaction, the polymer chains are preferably bridged by polymerizing a monomer having two or more polymerizable functional groups together with a monomer corresponding to the repeating unit represented by the general formula (I). Is the method. Specific examples of the polymerizable functional group include those having the following structures, but the monomers having two or more polymerizable functional groups described above are the same or different from each other. Any monomer having two or more of them may be used.
[0070]
[Chemical Formula 10]

[0071]
Specific examples of monomers having two or more polymerizable functional groups include, for example, as monomers having the same polymerizable functional group, styrene derivatives such as divinylbenzene and trivinylbenzene; polyhydric alcohols (for example, ethylene glycol). , Diethylene glycol, triethylene glycol, polyethylene glycol # 200, # 400, # 600, 1,3-butylene glycol, neopentyl glycol, dipropylene glycol, polypropylene glycol, trimethylol blowan, trimethylolethane, pentaerythritol, etc.) Or methacrylic acid, acrylic acid or crotonic acid esters, vinyl teres or allyl ethers of polyhydroxyphenols (eg hydroquinone, resorcin, catechol and derivatives thereof); dibasic acids (eg malo Vinyl esters of acids, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, itaconic acid, etc., allylsteryl branch, vinylamide or allylamide; polyamines (eg ethylenediamine, 1,3-propylenediamine) , 1,4-butylenediamine, etc.) and a carboxylic acid containing a vinyl group (for example, methacrylic acid, acrylic acid, crotonic acid, allyl acetic acid, etc.).
[0072]
Examples of monomers having different polymerizable functional groups include, for example, carboxylic acids containing vinyl groups (for example, methacrylic acid, acrylic acid, methacryloyl acetic acid, acryloyl acetic acid, methacryloyl propionic acid, acryloyl propionic acid, itaconyl yl acetic acid, Vinyl of itaconyloxypropionic acid, a reactant of carboxylic anhydride and alcohol or amine (eg, allyloxycarbonyl bropionic acid, allyloxycarbonylacetic acid, 2-allyloxycarbonylbenzoic acid, allylaminocarbonylpropionic acid, etc.) Ester derivatives or amide derivatives containing groups (for example, vinyl methacrylate, vinyl acrylate, vinyl itaconate, allyl methacrylate, allyl acrylate, allyl itaconate, methacryloyl vinyl acetate, methacryloyl) Vinyl ropionate, allyl methacryloyl propionate, vinyloxycarbonylmethyl ester methacrylate, vinyloxycarbonylmethyloxycarbonyl ethylene acrylate, N-allylacrylamide, N-allylmethacrylamide, N-allyl itaconamide, methacryloylpropionate allylamide And the like, and condensates of amino alcohols (for example, aminoethanol, 1-aminopropanol, 1-aminobutanol, 1-aminohexanol, 2-aminobutanol, etc.) with a carboxylic acid containing a vinyl group. It is done.
The monomer having two or more polymerizable functional groups used in the present invention is polymerized using 10% by mass or less, preferably 8% by mass or less of the total monomers, and is soluble in the non-aqueous solvent of the present invention. A resin is formed.
[0073]
The dispersion stabilizer (P) of the present invention can be easily synthesized by a conventionally known synthesis method.
That is, at least a monomer corresponding to the repeating unit represented by the general formula (I) and the above-described polyfunctional monomer coexist and a polymerization initiator (for example, an azobis compound, a peroxide, etc.) is used. A polymerization method is simple and preferable.
The polymerization initiator used here is 0.5 to 15% by mass, preferably 1 to 10% by mass, based on 100 parts by mass of all monomers. The dispersion stabilizer (P) of the present invention produced as described above interacts with the insoluble resin particles and is adsorbed on the insoluble resin particles. The particles adsorbed with the dispersion stabilizer (P) are markedly improved in affinity to the non-aqueous solvent because the dispersion stabilizer (P) that is soluble in the non-aqueous solvent is crosslinked. In addition to the improvement of the lyophilicity of the insoluble resin particle interface in this way, the dispersion stabilizer (P) present in the non-aqueous solvent without adsorbing to the particles is further adsorbed by the dispersion stabilizer. It is presumed that the approach between particles is suppressed sterically. It is considered that the insoluble particles are prevented from aggregating and precipitating, and the redispersibility is remarkably improved.
[0074]
The weight average molecular weight (Mw) of the dispersion stabilizer (P) of the present invention is 5 × 10. ³ ~ 1x10 ⁶ Is preferred, more preferably 2 × 10 ⁴ ~ 3x10 ⁵ It is.
[0075]
In order to produce colored resin particles encapsulating the pigment used in the present invention, a colored component surface-treated in a non-aqueous solvent is dispersed into fine particles to form seed particles. A polymerization system in which a part of the main chain is crosslinked and a dispersion stabilizer (P) soluble in the non-aqueous solvent is added to benzoyl peroxide, azobis (2,4-dimethylvaleronitrile), azobis (4-methoxy-2, Polymerization may be performed in the presence of a polymerization initiator such as 4-dimethylvaleronitrile), azobisisobutyronitrile, or butyllithium.
[0076]
Dispersion stabilizers that are soluble in the non-aqueous solvent in which a part of the main chain of the monomer and polymer repeating component is cross-linked while the colored component surface-treated in a non-aqueous solvent is dispersed into fine particles to form seed particles. To specifically add P) and a polymerization initiator,
(1) A method of dropping a solution in which a monomer, a dispersion stabilizer (P), and a polymerization initiator are mixed and dissolved in a non-aqueous solvent, or a method of adding all at once or dividedly,
(2) Add a solution in which the dispersion stabilizer (P) is dissolved in the seed particles by dispersing the coloring component in a fine particle in a non-aqueous solvent, and then add the monomer and the polymerization initiator dropwise, or A method of adding in batches or divided,
(3) A solution in which a monomer, a dispersion stabilizer (P), and a polymerization initiator are mixed and dissolved in a non-aqueous solvent while the coloring component is dispersed in the form of fine particles in a non-aqueous solvent to form seed particles. A part is added, and after dispersion polymerization, a method of arbitrarily adding a mixture of the remaining monomer, dispersion stabilizer (P), and polymerization initiator,
(4) Disperse coloring components in a non-aqueous solvent in the form of fine particles to form seed particles, and add a part of the monomer to promote monomer absorption into the seed particles, and then the remaining monomer and dispersion A method in which the stabilizer (P) and the polymerization initiator are added dropwise, or all at once or divided.
It can be manufactured using any method.
[0077]
Next, the amount of each component forming the colored resin particles encapsulating the pigment will be described. The use ratio of the seed particles (colored component fine particles) and the monomer {(M) and, if necessary, the total amount of (B), (A) and / or (L)} is 5/95 to 95/5. The mass ratio is preferred, more preferably 10/90 to 80/20 mass ratio. The charging amount of the total amount of monomers is about 5 to 80 parts by mass, preferably 10 to 50 parts by mass with respect to 100 parts by mass of the nonaqueous solvent. A dispersion stabilizer (P) that is partially soluble in the colloidal form and is partially crosslinked with the polymer repeating component main chain and soluble in the non-aqueous solvent is 1 part by weight per 100 parts by weight of the total monomer used above. It is -100 mass parts, Preferably it is 3-50 mass parts. The amount of the polymerization initiator is suitably 0.1 to 5 mol% of the total monomers. The polymerization temperature is about 20 to 180 ° C, preferably 30 to 120 ° C. The reaction time is preferably 1 to 15 hours.
[0078]
When aromatic hydrocarbons such as toluene and xylene remain in the non-aqueous solvent used in the reaction, and when polar solvents such as alcohols, ketones, ethers and esters described above are used in combination, or When unreacted monomers remaining to be granulated remain, it is preferably removed by heating to a boiling point or higher of the solvent or monomer, or by distilling off under reduced pressure.
[0079]
The non-aqueous pigment-encapsulating resin particles produced as described above have a high discharge stability in which clogging does not occur in the nozzle portion because the pigment is uniformly dispersed in fine particles and the dispersion stability of the dispersion is excellent. An oil-based ink for an ink jet printer is provided. Further, it has excellent drying properties on recording paper, water resistance and light resistance of recorded images, and has a high degree of scratch resistance. Furthermore, it is possible to easily obtain pigment-encapsulating resin particles uniformly dispersed in a non-aqueous solvent, and to control the charge polarity and to improve the charge stability over time. Provide a method. Moreover, it has the characteristic that functions, such as fixing property and charge property, can be introduce | transduced into the pigment inclusion resin particle by selecting a monomer appropriately.
[0080]
The following examples show that the ink composition of the present invention is useful as an oil-based ink for inkjet printers. As an ink jet printer, a piezoelectric method and an electrostatic method ink jet printer will be described as an example. However, the present invention is not limited to these methods, and the present invention can be applied to an ink jet printer represented by a slit jet such as a thermal method or NTT.
[0081]
The electrostatic ink jet printer will be further described.
1 and 2 are schematic diagrams for explaining an example of an ejection head. FIG. 1 is a diagram showing a configuration of a line scanning type multi-channel inkjet head, and shows a section of ejection electrodes corresponding to recording dots. In the drawing, ink 100 is supplied between a head substrate 102 and a discharge electrode substrate 103 from a circulation mechanism 111 including a pump through an ink supply channel 112 connected to the head block 101, and the ink formed in the head block 101 is also the same. The ink is recovered by the ink circulation mechanism 111 through the recovery channel 113. The discharge electrode substrate 103 includes an insulating substrate 104 having a through hole 107 and a discharge electrode 109 formed on the recording medium side around the through hole 107. On the other hand, a convex ink guide 108 is disposed on the head substrate 102 at a substantially central position of the through hole 107. The convex ink guide 108 is made of an insulating member such as plastic resin or ceramics, and is arranged at the same row interval and pitch so that the center is equal to the through hole 107, and is held on the head substrate 102 by a predetermined method. Yes. Each convex ink guide 108 has a shape in which the tip of a flat plate having a constant thickness is cut into a triangle or a trapezoid, and the tip becomes the ink droplet flying position 110. Each convex ink guide 108 may form a slit-like groove from the tip thereof, and the ink supply to the ink flying position 110 is smoothly performed by the capillary action of the slit, thereby improving the recording frequency. I can do it. In addition, any surface of the ink guide may have conductivity as required. In that case, the conductive portion is electrically floated so that the ink can be effectively applied with a small voltage applied to the ejection electrode. An electric field can be formed at the flight position. Each convex ink guide 108 protrudes in the ink droplet flying direction by a predetermined distance substantially perpendicularly from each through hole. A recording medium 121, which is a recording sheet, is disposed opposite to the tip of the convex ink guide 108, and a counter electrode that also serves as a platen for guiding the recording medium 121 on the back surface of the recording medium 121 opposite to the head substrate 102. 122 is arranged. In addition, a migration electrode 140 is formed at the bottom of the space formed between the head substrate 102 and the ejection electrode substrate 103. By applying a predetermined voltage to the migration electrode 140, the migration of the ink in the ink guide in the ejection position direction is performed. Charged particles can be electrophoresed to increase ejection responsiveness.
[0082]
Next, a specific configuration example of the discharge electrode substrate 103 will be described with reference to FIG. FIG. 2 is a view of the discharge electrode substrate 103 as viewed from the recording medium 121 side. A plurality of discharge electrodes are arranged in an array in two rows in the main scanning direction, and a through hole 107 is formed at the center of each discharge electrode. In addition, individual discharge electrodes 109 are formed around the through-holes 107, respectively. In this embodiment, the inner diameter of the discharge electrode 109 is set to be slightly larger than the diameter of the through hole 107, but it may be the same as the diameter of the through hole 107. Here, the insulating substrate 104 is made of polyimide having a thickness of about 25 to 200 μm, the discharge electrode 109 is made of copper foil having a thickness of about 10 to 100 μm, and the inner diameter of the through hole 107 is about 150 to 250 μmΦ.
[0083]
Next, the recording operation of the electrostatic ink jet recording apparatus will be described. Here, a case where positively charged ink is used will be described as an example, but the present invention is not limited to this example. At the time of recording, the ink 100 supplied from the ink circulation mechanism 111 via the ink supply channel 112 is supplied from the through hole 107 to the ink flying position 110 at the tip of the convex ink guide 108, and a part of the ink recovery channel. The ink is recovered by the ink circulation mechanism 111 through 113. Here, a voltage of, for example, +1.5 kV is applied as a bias from the bias voltage source 123 to the ejection electrode 109, and a pulse voltage of, for example, +500 V is applied as a signal voltage corresponding to the image signal from the signal voltage source 124 to the discharge electrode 109. Superposed on the discharge voltage 109. At this time, a voltage of +1.8 kV is applied to the migration electrode 140. On the other hand, the counter electrode 122 provided on the back surface of the recording medium 121 is set to a ground voltage of 0 V as shown in the figure. In some cases, the recording medium 121 side may be charged to, for example, −1.5 kV to obtain a bias voltage. In this case, an insulating layer is provided on the surface of the counter electrode 122, the recording medium is charged by a corona charger, a scorotron charger, a solid ion generator or the like, and the discharge electrode 109 is grounded, for example, and a signal voltage source 124 is connected thereto. As a signal voltage corresponding to the image signal from, for example, a pulse voltage of +500 V is superimposed on the ejection voltage 109 at the time of ON. At this time, a voltage of +200 V is applied to the migration electrode 140. Now, when the discharge voltage 109 is in an ON state (a state in which 500 V is applied) and a voltage of 2 kV in total, in which a 500 V pulse voltage is superimposed on the bias DC 1.5 kV, is applied, the ink droplet flying position 110 at the tip of the convex electrode 108 is applied. Then, the ink droplet 115 is ejected, pulled in the direction of the counter electrode 122, and ejected toward the recording medium 121 to form an image.
[0084]
In order to improve the accuracy of landing on the recording medium by precisely controlling the flying of the ink droplets after the flight, an intermediate electrode is provided between the ejection electrode and the recording medium, or a guard electrode for suppressing electric field interference between the ejection electrodes. Of course, a means such as providing the above is used, but it should be understood that the present embodiment can be suitably used in this embodiment as needed. Further, a porous body may be provided between the head base plate 102 and the discharge electrode substrate 103. In this case, it is possible to prevent the influence of the change in the ink internal pressure due to the movement of the ink jet head and the like, and the through hole after the ink droplet discharge Ink liquid supply to 107 parts is quickly achieved. Therefore, the flying of the ink droplet 115 is stabilized, and a good image with a stable density can be recorded on the recording medium 121 at high speed.
[0085]
[Example]
Examples of the present invention will be described below.
Synthesis Example of Dispersion Stabilizer 1: Dispersion Stabilizer (P-1)
A mixed solution of 100 g of octadecyl methacrylate, 2 g of divinylbenzene and 200 g of toluene was heated to a temperature of 85 ° C. while stirring under a nitrogen stream. 3.0 g of 2,2′-azobisisobutyronitrile (abbreviation AIBN) was added and reacted for 4 hours. I. B. 1.0 g of N was added and reacted for 2 hours. I. B. 0.5 g of N was added and reacted for 2 hours. After cooling, this mixed solution was reprecipitated in 1.5 L of methanol, and the white powder was collected by filtration and dried to obtain 88 g of powder. The weight average molecular weight of the obtained polymer was 3.3 × 10 ⁴ Met.
[0086]
Synthesis Examples 2-14 of Dispersion Stabilizer: Dispersion Stabilizers (P-2) to (P-14)
In Synthesis Example 1, each dispersion stabilizer was synthesized in the same manner as in Synthesis 1 except that the monomers shown in Table A below were used instead of octadecyl methacrylate. The weight average molecular weight of each dispersion stabilizer is 3.0 × 10 ⁴ ~ 5.0 × 10 ⁴ Met.
[0087]
[Table 1]

[0088]
Dispersion Stabilizer Synthesis Examples 15 to 27: Dispersion Stabilizers (P-15) to (P-27)
In Synthesis Example 1, instead of 2 g of divinylbenzene, which is a polyfunctional monomer for cross-linking, the same operations as in Synthesis Example were performed except that the polyfunctional monomer or oligomer shown in Table B below was used. A dispersion stabilizer was synthesized. The weight average molecular weight of each dispersion stabilizer is 3.0 × 10 ⁴ ~ 6.0 × 10 ⁴ Met.
[0089]
[Table 2]

[0090]
Synthesis Example 28 of Dispersion Stabilizer: Dispersion Stabilizer (P-28)
A mixed nose of 95 g of octadecyl methacrylate, 5 g of N-methoxymethyl acrylamide, 150 g of toluene and 50 g of isobropanol was heated to a temperature of 75 ° C. under a nitrogen stream. A. I. B. N. Was added and reacted for 8 hours. Next, using Dean-Stark, it heated at the temperature of 110 degreeC and stirred for 6 hours. The solvent isopropanol used and methanol by-produced in the reaction were removed. After cooling, it was reprecipitated in 1.5 L of methanol, and the white powder was collected by filtration and dried. Yield 82g, weight average molecular weight 5.6 × 10 ⁴ Met.
[0091]
Example 1
<Preparation of pigment dispersion>
A 20% solution prepared by dissolving a pigment dispersant (D-1) having the following structure in Isopar H by heating was used as a pigment dispersant. 88.25 parts by mass of the pigment dispersant solution, 17.65 parts by mass of Microlith Black CT (manufactured by Ciba Specialty Chemicals) treated with a rosin ester resin as a black processed pigment, 29.4 parts by mass of Isopar H The mixture was mixed with 250 parts by mass of glass beads with a paint shaker (Toyo Seiki KK) for 30 minutes. Next, the glass beads were separated by filtration, and then dispersed for 3 hours at a rotational speed of 3000 rpm using a high-speed dispersion mixing apparatus Dynomill (trade name; KDL). The media used glass beads MK-3GX. When the volume average particle diameter of the pigment particles in the dispersion was measured with an ultracentrifugal automatic particle size distribution analyzer CAPA700 (Horiba Seisakusho), it was well dispersed with 0.16 μm.
[0092]
Embedded image

[0093]
<Preparation of colored resin particles>
85.8 g of the filtrate (solid content 23.3%) of the processed pigment dispersion obtained by filtering the glass beads was placed in a four-necked flask and heated at a temperature of 80 ° C. for 3 hours with stirring under a nitrogen stream. Next, in this processed pigment dispersion, 2 g of (P-1) as a dispersion stabilizer (P) as a powder, 22.0 g of methyl methacrylate, 28.0 g of methyl acrylate and 120 g of ISOPAR H are mixed in a mixed solution. , 2'-azobis (2,4-dimethylvaleronitrile) 1.0 g as a feed solution was added dropwise at a dropping rate of 2.5 ml / min, followed by reaction for 3 hours. About 20 minutes after the start of dropping, heat generation started, and the temperature of the reaction solution rose about 5 ° C. After the reaction for 3 hours, the temperature was raised to 90 ° C. and stirred for 2 hours to distill off unreacted monomers. The black resin particle dispersion obtained by passing through a 200-mesh nylon cloth after cooling had a polymerization rate of 97% and a volume average particle size of 0.24 μm. The resulting black resin particle dispersion was also good in dispersion after storage for 1 month.
When the black resin particle dispersion was observed with an S-800 field emission scanning electron microscope (manufactured by Hitachi, Ltd.), microlith black pigment particles of about 100 nm grew into spherical resin particles of about 180 nm after dispersion polymerization. It was found that the dropped monomer was absorbed and polymerized in the seed pigment particles.
Further, when the black particle dispersion was observed with a transmission scanning electron microscope, it was found that the pigment particles of the seed were encapsulated in the spherical colored resin particles of about 180 nm after the dispersion polymerization.
From the above, it can be seen that the colored resin particles produced by the seed dispersion polymerization of the present invention are colored resin particles containing a rosin ester resin-treated pigment inside.
[0094]
<Preparation of ink composition: (IJ-1)>
The colored resin particle dispersion is once concentrated by distilling off the solvent and diluted with Isopar G. The viscosity is 13 cp (E-type viscometer, measured at a temperature of 25 ° C.) and the surface tension is 23 mN / m (Kyowa Interface Science). An ink composition (IJ-1) of an automatic surface tension meter manufactured by a company, measured at a temperature of 25 ° C. was prepared. Using a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation) as an ink jet recording apparatus, filling the ink composition (IJ-1), and drawing on Fuji Photo Film Inkjet Paper High Grade Special Paper, nozzle clogging It was discharged stably. The obtained drawn image was clear and free from bleeding and had an image density of 1.8. Next, a solid pattern was printed, and after the printed matter was dried, the solid portion was rubbed with a finger, and it was found that there was no background stain and it was extremely excellent in scratch resistance. The ink composition did not precipitate and agglomerate even when stored for a long period of time, had very good dispersibility, and could be used for continuous printing for a considerable period of time, giving excellent sharpness printing.
[0095]
Example 2
<Preparation of pigment dispersion>
100 parts by mass of carbon black # 30 (manufactured by Mitsubishi Chemical Corporation) as a black pigment, ethylene / stearyl acrylate copolymer (95/5 molar ratio) as a resin for polymer treatment, and 200 parts by mass were pre-pulverized with a trioblender and mixed well. Thereafter, the mixture was melt-kneaded (20 minutes) with a three-roll mill heated to 120 ° C. The pigment kneaded product was pulverized with a pin mill.
Next, 10 parts by mass of a pigment kneaded product, 65 parts by mass of Isopar H, 20 parts by mass of a 20 wt% solution prepared by heating and dissolving a pigment dispersant (D-2) having the following structure in Isopar H, and 3G-X glass beads The mixture was mixed with 250 parts by mass with a paint shaker (Toyo Seiki KK) for 60 minutes. Next, the glass beads were separated by filtration, and then dispersed for 3 hours at a rotational speed of 3000 rpm using a high-speed dispersion mixing apparatus Dynomill (trade name; KDL). The media used glass beads MK-3GX. When the volume average particle size of the pigment particles in the dispersion was measured with an ultracentrifugal automatic particle size distribution analyzer CAPA700 (Horiba Seisakusho), it was well dispersed as 0.16 μm.
[0096]
Embedded image

[0097]
<Preparation of colored resin particles>
214.3 g of the pigment dispersion filtrate (solid content: 14.0%) obtained by filtering the glass beads was placed in a four-necked flask and heated at 75 ° C. for 1 hour with stirring under a nitrogen stream. Next, in this pigment dispersion, as in Example 1, 4 g of dispersion stabilizer (P-2) in powder form, 6.0 g of methyl methacrylate, 14.0 g of methyl acrylate, and 80 g of Isopar H were mixed. A solution obtained by adding 0.5 g of 2,2′-azobis (2,4-dimethylvaleronitrile) to the solution was added dropwise as a feed solution over 1 hour, and then reacted for 3 hours. About 15 minutes after the start of dropping, heat generation started, and the temperature of the reaction solution rose about 4 ° C. After the reaction for 3 hours, the temperature was raised to 90 ° C., and the mixture was stirred for 2 hours while increasing the nitrogen flow rate to distill off the unreacted monomer. The black resin particle dispersion had a polymerization rate of 96.0% and a volume average particle size of 0.22 μm. The resulting black resin particle dispersion was also good in dispersion after storage for 1 month.
[0098]
<Preparation of ink composition: (IJ-2)>
The colored resin particle dispersion was once concentrated by distilling off the solvent and diluted with Isopar G to prepare an ink composition (IJ-2) having a viscosity of 13 cp and a surface tension of 23 mN / m. When the ink composition (IJ-2) was printed in the same manner as in Example 1 with a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation), a clear print of good quality without bleeding was given. Further, when the scratch resistance was examined in the same manner as in Example 1, it was found that there was no background contamination and it was extremely excellent in scratch resistance. The ink composition had good dispersibility because it did not precipitate and agglomerate even when stored for a long time.
[0099]
Example 3
<Preparation of pigment dispersion>
After stirring 10 parts by mass of carbon black # 100 (manufactured by Mitsubishi Chemical Corporation) as a black pigment and 100 parts by mass of water with a flasher, a styrene / vinyltoluene / lauryl methacrylate copolymer (40/58/2 mol) was used as a resin for polymer treatment. 60 parts by weight of a 33% toluene solution was further added to the flasher and stirred. Subsequently, it heated and pressure-reduced, the water | moisture content and the solvent were removed, and the black lump thing of the water content 1 mass% was obtained. The black lump was vacuum-dried to completely remove water, and then pulverized with a sample mill to obtain a black powder of 0.1 to 0.01 mm. In Example 2, the above black powder was used in place of the pigment kneaded material, and the pigment dispersant (D-3) having the following structure was used in place of (D-2) as the pigment dispersant. The pigment dispersion was carried out in the same manner as described above. The black pigment dispersion obtained after filtering out glass beads had a volume average particle size of 0.13 μm and good dispersibility.
[0100]
Embedded image

[0101]
<Preparation of colored resin particles>
In Example 2, 4 g of (P-3) was used instead of the dispersion stabilizer (P-2) using the filtrate of the pigment dispersion obtained by filtering glass beads (solid content: 13.0%) as seed particles. Other than that, dispersion polymerization was performed in exactly the same manner as in Example 2. The resulting black resin particle dispersion had a polymerization rate of 98.0% and a volume average particle size of 0.23 μm. The resulting black resin particle dispersion was also good in dispersion after storage for 1 month.
[0102]
<Preparation of ink composition: (IJ-3)>
The pigment resin particle dispersion was adjusted to a viscosity of 13 cp and a surface tension of 23 mN / m to obtain an ink composition (IJ-3). When the ink composition (IJ-3) was printed in the same manner as in Example 1 with a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation), high-quality clear printing without blurring was given. Further, when the scratch resistance was examined in the same manner as in Example 1, it was found that there was no background contamination and it was extremely excellent in scratch resistance. The ink composition had good dispersibility because it did not precipitate and agglomerate even when stored for a long time.
[0103]
Comparative Example 1
<Preparation of comparative pigment dispersion>
5 parts by weight of alkali blue as a blue pigment, 5 parts by weight of lauryl methacrylate / acrylic acid copolymer (composition ratio 95/5 wt / wt) as a pigment dispersant, paint shaker (90 parts by weight of ISOPAR H and 250 parts by weight of glass beads) The mixture was mixed with Toyo Seiki KK) for 30 minutes. Next, the glass beads are separated by filtration, then dispersed with a high-speed dispersion mixing apparatus Dynomill (trade name; KDL) for 3 hours at a rotational speed of 3000 rpm, and the volume average particle size of the pigment particles in the dispersion is determined as an ultracentrifugal automatic particle size distribution. When measured with a measuring apparatus CAPA700 (Horiba Seisakusho), it was well dispersed with 0.13 μm.
[0104]
<Comparison colored resin particles>
208.3 g of the pigment dispersion filtrate (solid content: 9.6%) obtained by filtering the glass beads was placed in a four-necked flask and heated at 80 ° C. for 3 hours while stirring under a nitrogen stream. Next, in this pigment dispersion, in the same manner as in Example 1, 8 g of the dispersion stabilizer (P-1), 12.0 g of methyl methacrylate, 28.0 g of methyl acrylate, and 120 g of Isopar H were added to a mixed solution. A solution obtained by adding 1.0 g of 2'-azobis (2,4-dimethylvaleronitrile) as a feed solution was added dropwise at a dropping rate of 2.5 ml / min, and then reacted for 3 hours. About 15 minutes after the start of dropping, heat generation started and the temperature of the reaction solution increased by about 5 ° C., but coarse particles adhered to the wall of the flask, and a large amount of precipitate was observed at the bottom of the flask after the reaction. . The colored resin particles of Comparative Example 1 could not be used for the next ink composition due to the generation of coarse particles and sediment.
[0105]
Comparative Examples 2-3
In Example 1, instead of the rosin ester resin-treated black pigment Microlith Black CT (manufactured by Ciba Specialty Chemicals), a blue pigment treated with the following polymer (CI Pigmet Blue 15: The pigment dispersion was performed in the same manner as in Example 1 except that 3) was used.

[0106]
The pigment dispersions of Comparative Examples 2-3 obtained by filtering glass beads after dispersion had a volume average particle size of 1.48 μm in Comparative Example 2 and 1.67 μm in Comparative Example 3. Since the pigment dispersion liquids of Comparative Examples 2 to 3 have coarse particles and precipitates are formed with the passage of time, the dispersibility is not good, so that they could not be used for the next seed polymerization.
[0107]
From Examples 1 to 3 and Comparative Examples 1 to 3, the pigment treated with the polymer as in the present invention is specifically made into fine particles and has good dispersion stability, and a polymer is used as a dispersion stabilizer. Since the dispersion stabilizer in which a part of the main chain of the component is cross-linked is used, the seed dispersion polymerization proceeds well, and the colored resin particles containing the polymer-treated pigment produced by the seed dispersion polymerization are It has been found that the ink exhibits good ink properties such as clear print image quality, extremely excellent scratch resistance, and good long-term dispersibility.
[0108]
Example 4
<Preparation of pigment dispersion>
Carbon black # 30 (Mitsubishi Chemical Co., Ltd.) 100 parts by mass as a black pigment, methyl methacrylate / stearyl methacrylate copolymer (9/1 molar ratio) as a resin for polymer treatment, and 200 parts by mass are pre-ground with a trioblender and mixed well. Then, it was melt-kneaded (20 minutes) with a three-roll mill heated to 120 ° C. The pigment kneaded product was pulverized with a pin mill.
Next, 10 parts by mass of a pigment kneaded product, 65 parts by mass of Isopar G, and 25 parts by mass of a 20 wt% solution prepared by heating and dissolving Sorprene 1205 (produced by Asahi Kasei Co., Ltd., styrene / butadiene copolymer) as a pigment dispersant in Isopar G. , And 250 parts by mass of 3G-X glass beads were mixed with a paint shaker (Toyo Seiki KK) for 60 minutes. Next, the glass beads were separated by filtration, and then dispersed for 3 hours at a rotational speed of 3000 rpm using a high-speed dispersion mixing apparatus Dynomill (trade name; KDL). The media used glass beads MK-3GX. When the volume average particle diameter of the pigment particles in the dispersion was measured with an ultracentrifugal automatic particle size distribution analyzer CAPA700 (Horiba Seisakusho), it was well dispersed as 0.21 μm.
[0109]
<Preparation of colored resin particles>
214.3 g of the pigment dispersion filtrate (solid content: 14.0%) obtained by filtering the glass beads was placed in a four-necked flask and heated at a temperature of 50 ° C. for 1 hour with stirring under a nitrogen stream. Next, in this pigment dispersion, 4 g of the above dispersion stabilizer (P-2) as a powder, 20.0 g of methyl acrylate and 80 g of Isopar H in a mixed solution of 2,2′-azobis (4-methoxy- 2,4-dimethylvaleronitrile) (0.7 g) was added as a feed solution dropwise over 1 hour, followed by reaction for 3 hours. About 20 minutes after the start of dropping, heat generation started, and the temperature of the reaction solution rose about 5 ° C. After the reaction for 3 hours, the temperature was raised from 50 ° C. to 80 ° C. and the nitrogen flow rate was increased, and the mixture was stirred for 2 hours to distill off unreacted monomers. After cooling, the black resin particle dispersion obtained by passing through a 200-mesh nylon cloth had a polymerization rate of 92% and a volume average particle size of 0.24 μm. The resulting black resin particle dispersion was also good in dispersion after storage for 1 month.
[0110]
<Preparation of ink composition: (IJ-4)>
The colored resin particle dispersion was once concentrated by distilling off the solvent and diluted with Isopar G to prepare an ink composition (IJ-4) having a viscosity of 13 cp and a surface tension of 23 mN / m. When the ink composition (IJ-4) was printed in the same manner as in Example 1 with a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation), high-quality clear printing without blurring was given. Further, when the scratch resistance was examined in the same manner as in Example 1, it was found that there was no background contamination and it was extremely excellent in scratch resistance. The ink composition had good dispersibility because it did not precipitate and agglomerate even when stored for a long time.
[0111]
Comparative Example 4
<Comparison Ink Composition: Preparation of (IJR-1)>
A comparative ink composition (IJR-1) was prepared in the same manner as the ink composition (IJ-4) except that a pigment particle dispersion of seed particles was used instead of the colored resin particles of Example 4. The ink had a viscosity of 12 cp and a surface tension of 23 dyne / cm. The ink composition for comparison (IJR-1) was printed with a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation) in the same manner as in Example 1, giving a print without bleeding, but pointing to the solid image portion. It was found that the image area was easily removed by rubbing with, and the scratch resistance was extremely poor. Further, it has been found that in order to prevent the printed image portion obtained from being rubbed with a finger, it is necessary to heat and fix the print recording body to 120 ° C. or higher.
[0112]
From the experimental results of the ink composition (IJ-4) of the present invention and the comparative ink composition (IJR-1), a part of the polymer component was crosslinked using the pigment treated with the polymer as in the present invention as seed particles. Colored resin particles coated with a low-softening resin by seed dispersion polymerization using a dispersion stabilizer that produces clear print image quality, good easy fixability, excellent scratch resistance, and good long-term dispersibility It was found that the ink characteristics were good.
[0113]
Example 5
<Preparation of pigment dispersion>
In Example 1, instead of the black pigment Microlith Blue CT (manufactured by Ciba Specialty Chemicals), yellow pigment Microlithero-3R-T (manufactured by Ciba Specialty Chemicals) was used. Pigment dispersion was performed exactly as in Example 1. The dispersion of the yellow pigment obtained after filtering out the glass beads had a good dispersibility with a volume average particle size of 0.20 μm.
[0114]
<Preparation of colored resin particles>
100 g of a yellow pigment dispersion (solid content 20.0%) was placed in a four-necked flask and heated at a temperature of 80 ° C. for 2 hours with stirring under a nitrogen stream. In Example 1, as a dispersion stabilizer, (P-1) was mixed in a mixed solution of 4 g of powder, 6.0 g of methyl methacrylate, 12.0 g of methyl acrylate, 2.0 g of dimethylaminoethyl methacrylate and 80 g of ISOPAR H. Except that the solution containing 0.6 g of 2,2'-azobis (2,4-dimethylvaleronitrile) was added as a feed solution and dropped at a drop rate of 2.0 ml / min and reacted for 3 hours, it was exactly the same as Example 1. The reaction operation was performed. The temperature of the reaction solution rose about 4 ° C. The obtained yellow resin dispersion had a polymerization rate of 95%, a volume average particle size of 0.26 μm, and a good dispersion state after storage for 1 month.
[0115]
<Preparation of ink composition: (IJ-5)>
The yellow resin particle dispersion was diluted with Isopar G so that the resin particle component was 6.0%. Next, an ink composition (IJ-5) was prepared by adding an octadecene-half-maleic acid octadecylamide copolymer as a charge control agent to 0.01 g / Isopar G 1 liter. Measurement of the charge amount of the ink composition (IJ-5) was carried out using the development characteristics apparatus described in Japanese Examined Patent Publication No. 64-696 (applied voltage 500 V, initial value of time change of voltage induced on the back surface of the applied electrode was measured. ) The ink composition (IJ-5) showed a clear positive charge with an overall charge of 240 mV and a yellow resin particle charge of 201 mV, and was found to be extremely stable with almost no change in the amount of charge after one month. . It was also found that the amount of charge can be easily controlled by the amount of charge control agent.
[0116]
Comparative Example 5
<Production of Comparative Ink Composition: (IJR-2)>
In Example 5, the yellow pigment dispersion as seed particles was converted into an ink in the same manner as the ink composition (IJ-5) to prepare a comparative ink composition (IJR-2). When the charge amount of the comparative ink composition (IJR-2) was measured, the charge polarity was negative charge, the overall charge was 90 mV, and the charge of the yellow pigment particles was 13 mV.
From Example 5 and Comparative Example 5, the charge polarity of the seed pigment yellow pigment Microlithero-3R-T (comparative ink composition (IJR-2)) was originally negatively charged, but the main chain of the polymer component The colored resin particles of the present invention (ink composition (IJ-5)) coated with a resin by seed dispersion polymerization using a dispersion stabilizer in which a part of the resin is crosslinked show a positive charge with a clear charge polarity. It can be seen that the amount can be easily controlled by the amount of the charge control agent. That is, it can be seen that the charge amount can be freely controlled by coating the surface of the pigment with resin by seed dispersion polymerization, regardless of the charge polarity of the original pigment.
[0117]
<Image drawability>
A 100 dpi 64-channel electrostatic ink jet head having the head structure shown in FIG. 1 was used as the ink jet device, and the ink composition (IJ-5) was filled in the ink tank. After removing dust on the surface of the coated recording paper as a recording medium by air pump suction, the ejection head was brought close to the coated recording paper to the drawing position, and ink was ejected and drawn at a drawing resolution of 600 dpi. At this time, the drawing was performed while adjusting the pulse voltage and changing the dot area in 16 steps within a dot diameter range of 15 μm to 60 μm. The drawn image gave a clear image of good quality with satisfactory density without blur. The ejection stability from the ink head was also good, there was no clogging, and stable dot-shaped printing was possible even in image drawing. Further, when the scratch resistance was examined in the same manner as in Example 1, it was found that there was no background stain at all and it was extremely excellent in scratch resistance. The ink composition (IJ-5) had good dispersibility because no sedimentation aggregation was observed even when stored for a long period of time.
[0118]
On the other hand, when a comparative ink composition (IJR-2) was used and drawn in the same manner as described above with the negative polarity of the pulse voltage applied to the ejection head, the drawn image was severely blurred and the image density was low. Further, since a discharge failure occurred, a satisfactory image could not be obtained due to missing images.
From the above results, since the pigment resin particles (ink composition (IJ-5)) coated with the resin by seed dispersion polymerization of the present invention have a clear positive charge and a sufficient charge amount, the electrostatic ink jet apparatus It was found that the ink exhibits good ink characteristics such as clear print image quality, good ejection stability, extremely excellent scratch resistance, and good long-term dispersibility.
[0119]
Examples 6-19
<Preparation of pigment dispersion>
In Example 1, 50 wt% of (D-3) is used with respect to the processed pigment instead of the pigment dispersant (D-1), and the blue processed pigment microlith is used instead of the black processed pigment microlith Black CT. Pigment dispersion was performed in the same manner as in Example 1 except that Blue 4G-T (manufactured by Ciba Specialty Chemicals) was used. The pigment dispersion obtained after filtering out the glass beads had a volume average particle size of 0.16 μm and good dispersibility. Using this blue pigment dispersion, seed dispersion polymerization was performed to prepare colored resin particles and ink compositions (IJ-6) to (IJ-19).
[0120]
<Preparation of colored resin particles>
In Example 1, 157.5 g of a blue processed pigment dispersion (solid content 19.1%) was used, and 8 g of the dispersion stabilizer (P) described in Table C below was powdered and 40 g of monomer was used. A solution obtained by adding 120 g of Isopar G and 1 mol% of 2,2′-azobis (2,4-dimethylvaleronitrile) to the monomer was added dropwise to the feed solution in 2 hours. The same reaction procedure was performed. The temperature of the reaction solution increased by about 3 to 8 ° C. The obtained blue particle dispersions 6 to 19 had a polymerization rate of about 89 to 98% and a volume average particle size of 0.20 to 0.26 μm. In addition, the blue particle dispersions 6 to 19 were also excellent in dispersion state after being stored for one month.
[0121]
<Ink composition: (IJ-6) to (IJ-19)>
Ink compositions (IJ-6) to (IJ-19) were prepared by adjusting the viscosity of the colored resin particle dispersions 6 to 19 to 12 to 14 cp and the surface tension to 22 to 24 mN / m, respectively. When the ink compositions (IJ-6) to (IJ-19) were printed with a color facsimile Saiyuki UX-E1CL (manufactured by Sharp Corporation) in the same manner as in Example 1, the ink compositions (IJ-6) to (IJ-6) IJ-19) gave a good quality clear print with satisfactory density without bleeding, and was very excellent in scratch resistance with no visible scum. In addition, the ink compositions (IJ-6) to (IJ-19) had good dispersibility because no sedimentation aggregation was observed even when stored for a long period of time.
[0122]
[Table 3]

[0123]
Example 20
When the ink composition (IJ-5) obtained in Example 5 was subjected to a printing test using an electrophotographic liquid developer using a Ricoh wet copying machine DT-2500, sufficient image density and good fixability were obtained. An image having was obtained. Further, this electrophotographic liquid developer has very little change in charge with time, and has excellent redispersibility and storage stability.
[0124]
【The invention's effect】
A resin-coated book obtained by seed dispersion polymerization using a polymer-treated pigment as a seed particle, in which a part of the polymer main chain is crosslinked in a non-aqueous solvent and is soluble in the non-aqueous solvent. The ink composition containing the pigment resin particles of the invention can provide an oil-based ink for an inkjet printer in which pigments are uniformly dispersed in fine particles and the dispersion stability of the pigment dispersion is excellent. Further, it is possible to provide oil-based ink for an ink jet printer having high ejection stability in which clogging at the nozzle portion does not occur. Further, it is possible to provide an oil-based ink for an ink jet printer which is excellent in dryness on recording paper, water resistance and light resistance of a recorded image, and has high scratch resistance. Another object of the present invention is to provide an oil-based ink for an electrostatic ink jet printer and a liquid developer for electrophotography that are excellent in dispersion stability and scratch resistance, and also excellent in charge polarity control and charge aging stability. . Furthermore, the manufacturing method for obtaining the ink for inkjet printers which consists of the resin particle which has the said characteristic and encloses the pigment disperse | distributed uniformly finely can be provided.
[0125]
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a line scanning type multi-channel inkjet head, and is a diagram illustrating a cross section of an ejection electrode corresponding to a recording dot.
FIG. 2 is a diagram of ejection electrodes as viewed from the recording medium side.

Claims (9)

A non-aqueous solvent having a relative dielectric constant of 1.5 to 20 and a surface tension of 15 to 60 mN / m (at 25 ° C.) is obtained by dispersing a coloring component obtained by surface-treating a colorant into the non-aqueous solvent in the form of fine particles. A polymer containing at least one monofunctional monomer (M) and a repeating unit represented by the following general formula (I), and a part of the polymer main chain, using the fine colored component fine particles as seed particles An ink-jet printer comprising colored resin particles obtained by adding at least one dispersion stabilizer (P) which is cross-linked and soluble in the non-aqueous solvent, and dispersion-polymerized in the presence of a polymerization initiator Oil-based ink composition.

In the general formula (I), X ¹ is ^one selected from —COO—, —OCO—, — (CH ₂ ) _k —OCO—, — (CH ₂ ) _k —COO— and —O—, or a combination thereof. Represents a linked group. k represents an integer of 1 to 3. a ¹ and ^{a 2,} which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, ^{-COO-Z 1} or ^{-COO-Z 1} (Z 1 via a hydrocarbon hydrogen Represents an atom or a hydrocarbon group which may be substituted. Y ¹ represents an aliphatic group having 6 to 32 carbon atoms. 2. The oil-based ink composition for an ink jet printer according to claim 1, wherein the colorant is at least one pigment selected from organic pigments and inorganic pigments, and the color component is surface-treated by coating the colorant with a polymer. . The oil-based ink composition for an ink jet printer according to claim 1, wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant. Monofunctional monomer using, as seed particles, colored component fine particles obtained by dispersing a colored component obtained by surface-treating a colorant in a non-aqueous solvent having a volume resistivity of 10 ⁹ Ωcm or more in the form of fine particles in the non-aqueous solvent. A dispersion stabilizer (P) which is a polymer containing at least one of (M) and a repeating unit represented by the following general formula (I), and a part of the polymer main chain is crosslinked and soluble in the non-aqueous solvent. A liquid developer for electrophotography characterized by containing colored resin particles obtained by subjecting a dispersion obtained by adding at least one of the above to dispersion polymerization in the presence of a polymerization initiator.

In the general formula (I), X ¹ is ^one selected from —COO—, —OCO—, — (CH ₂ ) _k —OCO—, — (CH ₂ ) _k —COO— and —O—, or a combination thereof. Represents a linked group. k represents an integer of 1 to 3. a ¹ and ^{a 2,} which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, ^{-COO-Z 1} or ^{-COO-Z 1} (Z 1 via a hydrocarbon hydrogen Represents an atom or a hydrocarbon group which may be substituted. Y ¹ represents an aliphatic group having 6 to 32 carbon atoms. The electrophotographic liquid developer according to claim 4, wherein the colorant is at least one pigment selected from organic pigments and inorganic pigments, and the color component is surface-treated by coating the colorant with a polymer. 5. The electrophotographic liquid developer according to claim 4, wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant. A non-aqueous solvent having a relative dielectric constant of 1.5 to 20 and a surface tension of 15 to 60 mN / m (at 25 ° C.) is obtained by dispersing a coloring component obtained by surface-treating a colorant into the non-aqueous solvent in the form of fine particles. A polymer containing at least one monofunctional monomer (M) and a repeating unit represented by the following general formula (I), and a part of the polymer main chain, using the fine colored component fine particles as seed particles A method for producing colored resin particles obtained by dispersing and dispersing a dispersion obtained by adding at least one dispersion stabilizer (P) that is crosslinked and soluble in the non-aqueous solvent in the presence of a polymerization initiator.

In the general formula (I), X ¹ is ^one selected from —COO—, —OCO—, — (CH ₂ ) _k —OCO—, — (CH ₂ ) _k —COO— and —O—, or a combination thereof. Represents a linked group. k represents an integer of 1 to 3. a ¹ and ^{a 2,} which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, ^{-COO-Z 1} or ^{-COO-Z 1} (Z 1 via a hydrocarbon hydrogen Represents an atom or a hydrocarbon group which may be substituted. Y ¹ represents an aliphatic group having 6 to 32 carbon atoms. The method for producing colored resin particles according to claim 7, wherein the colorant is at least one pigment selected from organic pigments and inorganic pigments, and the color component is surface-treated by coating the colorant with a polymer. The method for producing colored resin particles according to claim 7, wherein the seed particles are colored component fine particles obtained by dispersing and stabilizing the surface-treated colored component in a fine particle form in a non-aqueous solvent using a pigment dispersant.

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