JP3967960B2 - Inkjet recording sheet and method for producing the same - Google Patents

Description

【００６６】
上式中、Ｒ⁸¹〜Ｒ⁸⁴は置換基を有していてもよい有機基を表し、Ｒ⁸⁵及びＲ⁸⁶は、それぞれ独立に、置換基を有していてもよい有機基（Ｒ⁸¹〜Ｒ⁸⁴と同義）又は水素原子を表す。Ｒ⁸⁷は水素原子又はメチル基を表し、Ｒ⁸⁸は−ＣＯＯＲ⁸⁹、−ＣＮ、−ＣＯＮＲ⁹⁰Ｒ⁹¹を表す。ここで、Ｒ⁸⁹〜Ｒ⁹¹は、それぞれ独立に、水素原子、脂肪族基、芳香族基を表す。Ｇ^-は対アニオンを表す。
【００６７】
上記の有機基とは、炭化水素部位及び／又はハロゲン化水素部位を含む基であり、これ以外に水素、炭素、窒素、酸素、硫黄、リン、ケイ素、ホウ素、ハロゲンなどの原子、及び／又はこれらの組合わせからなる官能基を含んでいてもよい。このような例としては、例えば（置換）アルキル基、（置換）アラルキル基、（置換）アリール基、（置換）アシル基、（置換）スルホニル基、ヘテロ環類などが挙げられる。
【００６８】
Ｒ⁸¹〜Ｒ⁸⁴で表される有機基の具体例としては、アルキル基（例えばメチル、エチル、ｎ−プロピル、ｉ−プロピル、ｎ−ブチル、ｉ−ブチル、ｓｅｃ−ブチル、ｔ−ブチル、ｎ−ヘキシル、シクロヘキシル、ｎ−オクチル、２−エチルヘキシル、ｎ−デシル、ｎ−ドデシル、オクタデシル、１，３−ブタジエニル、１，３−ペンタジエニル等）；アラルキル基（例えばベンジル、フェニルエチル、ビニルベンジル、１−フェニルビニル、２−フェニルビニル等）；アリール基（例えばフェニル、ナフチル、トリル、ビニルフェニル等）が挙げられる。
【００６９】
更に、置換基を有する有機基としては、フロロエチル基、トリフロロエチル基、メトキシエチル基、フェノキシエチル基、ヒドロキシフェニルメチル基、クロロフェニル基、ジクロロフェニル基、トリクロロフェニル基、ブロモフェニル基、ヨードフェニル基、フロロフェニル基、ヒドロキシフェニル基、メトキシフェニル基、ヒドロキシフェニル基、アセトキシフェニル基、シアノフェニル基等が挙げられる。
【００７０】
また、水酸基を有するものとして、下記に示す基等が挙げられる。
【化２】

【００７１】
また、以下に示す有機基等が挙げられる。
−ＣＲ¹⁰¹Ｒ¹⁰²−ＣＯＯＲ¹⁰³
前記Ｒ¹⁰¹〜Ｒ¹⁰³は、それぞれ独立に、水素原子、脂肪族基、芳香族基を表し、例えば、メチル基、エチル基、ブチル基、ベンジル基、フェニル基等が挙げられる。
【００７２】
−ＣＯ−Ｒ¹⁰⁴−ＣＯＯＨ
前記Ｒ¹⁰⁴は、二価の連結基を表し、例えば、−ＣＨ₂ＣＨ₂−、−ＣＨ₂ＣＨ₂ＣＨ₂−、−ＣＨ＝ＣＨ−、及び下記連結基等が挙げられる。
【００７３】
【化３】

【００７４】
−ＣＯＲ¹⁰⁵、−ＣＯＯＲ¹⁰⁶、−ＣＯＮＨＲ¹⁰⁷、−ＣＳＮＨＲ¹⁰⁸、−ＳＯ₂Ｒ¹⁰⁹、−Ｐ(＝Ｏ)(ＯＲ¹¹⁰)₂
前記Ｒ¹⁰⁵〜Ｒ¹¹⁰は、それぞれ独立に、水素原子、脂肪族基、芳香族基を表し、例えば、メチル基、エチル基、プロピル基、ブチル基、オクタデシル基、ベンジル基、フェニル基、−ＣＨ＝ＣＨ−Ｐｈ、等が挙げられる。
【００７５】
また、Ｒ⁸⁷は、水素原子又はメチル基を表す。Ｒ⁸⁸は−ＣＯＯＲ¹¹¹、−ＣＮ、−ＣＯＮＲ¹¹²Ｒ¹¹³であり、Ｒ¹¹¹〜Ｒ¹¹³は、それぞれ独立に水素原子、脂肪族基、芳香族基を表す。
Ｒ¹¹¹〜Ｒ¹¹³の具体例としては、水素原子、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、ｉ−ブチル基、ｓｅｃ−ブチル基、ｔ−ブチル基、ｎ−ヘキシル基、シクロヘキシル基、ｎ−オクチル基、２−エチルヘキシル基、ｎ−デシル基、ｎ−ドデシル基、オクタデシル基、アリル基、ベンジル基、フェニル基、ナフチル基、ビフェニル基、１，１，１−トリフロロエチル基、２−ヒドロキシ−３−クロロプロピル基等が挙げられる。
【００７６】
Ｇ^-の具体例としては、ハロゲンイオン（Ｃｌ^-、Ｂｒ^-、Ｉ^-）、スルホン酸イオン、アルキルスルホン酸イオン、アリールスルホン酸イオン、アルキルカルボン酸イオン、アリールカルボン酸イオン等が挙げられる。
【００７７】
これらのポリアリルアミン誘導体の構造は特に限定されないが、得られた重合体は水溶性、或いは水と混和性のある有機溶媒に可溶である方が好ましいが、水分散性のラテックス粒子の形態でも使用することができる。
【００７８】
ポリアリルアミン及びその誘導体の具体例としては、ポリジメチルジアリルアンモニウムクロライド、ポリモノメチルジアリルアンモニウムクロライド、並びに、特公昭６２‐３１７２２号、特公平２‐１４３６４号、特公昭６３-４３４０２号、同６３-４３４０３号、同６３-４５７２１号、同６３-２９８８１号、特公平１-２６３６２号、同２-５６３６５号、同２-５７０８４号、同４-４１６８６号、同６-２７８０号、同６-４５６４９号、同６-１５５９２号、同４-６８６２２号、特許第３１９９２２７号、同３００８３６９号、特開平１０‐３３０４２７号、同１１‐２１３２１号、特開２０００‐２８１７２８号、同２００１‐１０６７３６号、特開昭６２-２５６８０１号、特開平７‐１７３２８６号、同７‐２１３８９７号、同９-２３５３１８号、同９-３０２０２６号、同１１‐２１３２１号、ＷＯ９９／２１９０１号、ＷＯ９９／１９３７２号、特開平５-１４０２１３号、特表平１１‐５０６４８８号等の各公報に記載の化合物が挙げられる。
【００７９】
前記無機媒染剤としては、多価の水溶性金属塩や疎水性金属塩化合物が挙げられる。例えば、マグネシウム、アルミナ、カルシウム、スカンジウム、チタン、バナジウム、マンガン、鉄、ニッケル、銅、亜鉛、ガリウム、ゲルマニウム、ストロンチウム、イットリウム、ジルコニウム、モリブデン、インジウム、バリウム、ランタン、セリウム、プラセオジミウム、ネオジミウム、サマリウム、ユーロピウム、ガドリニウム、ジスロプロシウム、エルビウム、イッテルビウム、ハフニウム、タングステン、ビスマスから選択される金属の塩又は錯体が挙げられる。
【００８０】
具体例としては、酢酸カルシウム、塩化カルシウム、ギ酸カルシウム、硫酸カルシウム、酢酸バリウム、硫酸バリウム、リン酸バリウム、塩化マンガン、酢酸マンガン、ギ酸マンガンニ水和物、硫酸マンガンアンモニウム六水和物、塩化第二銅、塩化アンモニウム銅（II）二水和物、硫酸銅、塩化コバルト、チオシアン酸コバルト、硫酸コバルト、硫酸ニッケル六水和物、塩化ニッケル六水和物、酢酸ニッケル四水和物、硫酸ニッケルアンモニウム六水和物、アミド硫酸ニッケル四水和物、硫酸アルミナ、アルミナミョウバン、塩基性ポリ水酸化アルミナ、亜硫酸アルミナ、チオ硫酸アルミナ、ポリ塩化アルミナ、硝酸アルミナ九水和物、塩化アルミナ六水和物、臭化第一鉄、塩化第一鉄、塩化第二鉄、硫酸第一鉄、硫酸第二鉄、フェノールスルホン酸亜鉛、臭化亜鉛、塩化亜鉛、硝酸亜鉛六水和物、硫酸亜鉛、四塩化チタン、テトライソプロピルチタネート、チタンアセチルアセトネート、乳酸チタン、ジルコニウムアセチルアセトネート、酢酸ジルコニル、硫酸ジルコニル、炭酸ジルコニウムアンモニウム、ステアリン酸ジルコニル、オクチル酸ジルコニル、硝酸ジルコニル、オキシ塩化ジルコニウム、
【００８１】
ヒドロキシ塩化ジルコニウム、酢酸クロム、硫酸クロム、硫酸マグネシウム、塩化マグネシウム六水和物、クエン酸マグネシウム九水和物、りんタングステン酸ナトリウム、クエン酸ナトリウムタングステン、１２タングストリン酸ｎ水和物、１２タングストけい酸２６水和物、塩化モリブデン、１２モリブドリン酸ｎ氷和物、硝酸カリウム、酢酸マンガン、硝酸ゲルマニウム、硝酸ストロンチウム、酢酸イットリウム、塩化イットリウム、硝酸イットリウム、硝酸インジウム、硝酸ランタン、塩化ランタン酢酸ランタン、安息香酸ランタン、塩化セリウム、硫酸セリウム、オクチル酸セリウム、硝酸プラセオジミウム、硝酸ネオジミウム、硝酸サマリウム、硝酸ユーロピウム、硝酸ガドリニウム、硝酸ジスプロシウム、硝酸エルビウム、硝酸イッテルビウム、塩化ハフニウム、硝酸ビスマス等が挙げられる。
【００８２】
前記無機媒染剤の中でも、アルミナ含有化合物、チタン含有化合物、ジルコニウム含有化合物、元素周期律表第IIIＢ族シリーズの金属化合物（塩又は錯体）が好ましい。
【００８３】
また、前記媒染剤を混合せずに、あるいは前記媒染剤と共に前記水溶性樹脂を分散剤として混合することができる。水溶性樹脂を混合した場合も、無機微粒子の分散性、経時での分散安定性を向上させることができる。
【００８４】
前記水溶性樹脂としては、例えば、親水性構造単位としてヒドロキシ基を有する樹脂であるポリビニルアルコール（ＰＶＡ）、アセトアセチル変性ポリビニルアルコール、カチオン変性ポリビニルアルコール、アニオン変性ポリビニルアルコール、シラノール変性ポリビニルアルコール、ポリビニルアセタール、セルロース系樹脂〔メチルセルロース（ＭＣ）、エチルセルロース（ＥＣ）、ヒドロキシエチルセルロース（ＨＥＣ）、カルボキシメチルセルロース（ＣＭＣ）、ヒドロキシプロピルセルロース（ＨＰＣ）等〕、キチン類、キトサン類、デンプン；エーテル結合を有する樹脂であるポリエチレンオキサイド（ＰＥＯ）、ポリプロピレンオキサイド（ＰＰＯ）、ポリエチレングリコール（ＰＥＧ）、ポリビニルエーテル（ＰＶＥ）；アミド基又はアミド結合を有する樹脂であるポリアクリルアミド（ＰＡＡＭ）、ポリビニルピロリドン（ＰＶＰ）、ポリアクリル酸ヒドラジド等が挙げられる。
また、解離性基としてカルボキシル基を有するポリアクリル酸塩、マレイン酸樹脂、アルギン酸塩、ゼラチン類等も挙げることができる。
【００８５】
以上の中でも、特にポリビニルアルコール又はその誘導体が好ましい。該ポリビニルアルコールの例としては、特公平４−５２７８６号、特公平５−６７４３２号、特公平７−２９４７９号、特許第２５３７８２７号、特公平７−５７５５３号、特許第２５０２９９８号、特許第３０５３２３１号、特開昭６３−１７６１７３号、特許第２６０４３６７号、特開平７−２７６７８７号、特開平９−２０７４２５号、特開平１１−５８９４１号、特開２０００−１３５８５８号、特開２００１−２０５９２４号、特開２００１−２８７４４４号、特開昭６２−２７８０８０号、特開平９−３９３７３号、特許第２７５０４３３号、特開２０００−１５８８０１号、特開２００１−２１３０４５号、特開２００１−３２８３４５号、特開平８−３２４１０５号、特開平１１−３４８４１７号等に記載されたものも使用できる。
【００８６】
水溶性樹脂を分散剤として無機微粒子分散液に混合する場合には、上述した分散剤の混合量の範囲内で使用できる。また、水溶性樹脂は、上記分散剤として用いるほか、色材受容層用塗布液の調製時に更に加えることが可能である。
したがって、水溶性樹脂の総量としては、色材受容層を形成したときの該層の全固形分質量に対して、９〜４０質量％が好ましく、１２〜３３質量％がより好ましい。
尚、本発明に係る色材受容層を主に構成する、後述の無機微粒子と水溶性樹脂とは、それぞれ単一素材であってもよいし、複数の素材の混合系を使用してもよい。
【００８７】
尚、透明性を保持する観点からは、微粒子特にシリカ微粒子に組合される水溶性樹脂の種類が重要となる。前記気相法シリカを用いる場合には、該水溶性樹脂としては、ポリビニルアルコール（ＰＶＡ）が好ましく、その中でも、鹸化度７０〜１００％のＰＶＡがより好ましく、鹸化度８０〜９９．５％のＰＶＡが特に好ましい。
【００８８】
前記ポリビニルアルコール（ＰＶＡ）は、その構造単位に水酸基を有するが、この水酸基と前記シリカ微粒子の表面シラノール基とが水素結合を形成するため、シリカ微粒子の二次粒子を網目鎖単位とした三次元網目構造を形成し易くなる。この三次元網目構造の形成によって、空隙率が高く充分な強度のある多孔質構造の色材受容層を形成されると考えられる。
インクジェット記録において、上述のようにして得られた多孔質の色材受容層は、毛細管現象によって急速にインクを吸収し、インクニジミの発生しない真円性の良好なドットを形成することができる。
【００８９】
また、ポリビニルアセタール、セルロース系樹脂〔メチルセルロース（ＭＣ）、エチルセルロース（ＥＣ）、ヒドロキシエチルセルロース（ＨＥＣ）、カルボキシメチルセルロース（ＣＭＣ）、ヒドロキシプロピルセルロース（ＨＰＣ）等〕、キチン類、キトサン類、デンプン；エーテル結合を有する樹脂であるポリエチレンオキサイド（ＰＥＯ）、ポリプロピレンオキサイド（ＰＰＯ）、ポリエチレングリコール（ＰＥＧ）、ポリビニルエーテル（ＰＶＥ）；アミド基またはアミド結合を有する樹脂であるポリアクリルアミド（ＰＡＡＭ）、ポリビニルピロリドン（ＰＶＰ）、ポリアクリル酸ヒドラジド、並びに、解離性基としてカルボキシ基を有するポリアクリル酸塩、マレイン酸樹脂、アルギン酸塩、ゼラチン類等の他の水溶性樹脂を併用してもよい。該他の水溶性樹脂と上記ポリビニルアルコールとを併用する場合、全水溶性樹脂中、ポリビニルアルコールの含有量は、５０質量％以上が好ましく、７０質量％以上が更に好ましい。
【００９０】
上記のカチオン性ポリマーの中でも、カチオン性媒染剤を分散剤とするのが好ましく、ポリジメチルジアリルアンモニウムクロライド、ポリモノメチルジアリルアンモニウムクロライドを少なくとも分散剤とするのが特に好ましく、この二種を組合せて混合するのが最も好ましい。
【００９１】
上記の水溶性樹脂は、無機微粒子の分散剤として用いるほか、色材受容層用塗布液の調製時において、予め調製した無機微粒子分散液に添加したり、あるいは別途水溶性樹脂を含む水溶液を調製しておき、これを無機微粒子分散液と混合する等して、バインダー成分として色材受容層に含有させることができる。水溶性樹脂は、後述の架橋剤によって架橋されることで強固で耐性に優れた色材受容層とすることができる。
【００９２】
塗布形成された色材受容層中における、無機微粒子(ｘ)と水溶性樹脂(ｙ)との質量含有比〔ＰＢ比（ｘ／ｙ）〕は、色材受容層の膜構造及び膜強度に大きな影響を与える。即ち、質量含有比〔ＰＢ比〕が大きくなると、空隙率、細孔容積、表面積（単位質量当り）が大きくなるが、密度や強度は低下する傾向にある。
本発明における前記質量含有比〔ＰＢ比（ｘ／ｙ）〕としては、ＰＢ比が大き過ぎることに起因する、膜強度の低下や乾燥時のひび割れを防止し、かつＰＢ比が小さ過ぎることによって、該空隙が樹脂によって塞がれ易くなり、空隙率が減少することでインク吸収性が低下するのを防止する観点から、１．５：１〜１０：１が好ましい。
【００９３】
インクジェットプリンターの搬送系を通過する場合、記録用シートに応力が加わることがあるので、色材受容層は充分な膜強度を有していることが必要である。またシート状に裁断加工する場合、色材受容層の割れや剥がれ等を防止する上でも、色材受容層には充分な膜強度を有していることが必要である。これらの場合を考慮すると、前記質量比（ｘ／ｙ）としては５：１以下がより好ましく、一方インクジェットプリンターで、高速インク吸収性を確保する観点からは、２：１以上であることがより好ましい。
【００９４】
例えば、平均一次粒子径が２０ｎｍ以下の気相法シリカ微粒子と水溶性樹脂とを、質量比（ｘ／ｙ）２：１〜５：１で水溶液中に完全に分散した塗布液を支持体上に塗布し、該塗布層を乾燥した場合、シリカ微粒子の二次粒子を網目鎖とする三次元網目構造が形成され、その平均細孔径が３０ｎｍ以下、空隙率が５０〜８０％、細孔比容積が０．５ｍｌ／ｇ以上、比表面積が１００ｍ²／ｇ以上の、透光性の多孔質膜を容易に形成することができる。
【００９５】
−無機微粒子−
インクジェット記録用シートの色材受容層は、無機微粒子を含有することにより多孔質構造が得られ、これによりインクの吸収性能が向上する。特に、該無機微粒子の色材受容層における固形分含有量が６０質量％以上、より好ましくは６５質量％を超えていると、更に良好な多孔質構造を形成することが可能となり、充分なインク吸収性を備えたインクジェット記録用シートが得られるので好ましい。ここで、無機微粒子の色材受容層における固形分含有量とは、色材受容層を構成する組成物中の水以外の成分に基づき算出される含有量である。
【００９６】
無機微粒子としては、例えば、シリカ微粒子、コロイダルシリカ、二酸化チタン、硫酸バリウム、珪酸カルシウム、ゼオライト、カオリナイト、ハロイサイト、雲母、タルク、炭酸カルシウム、炭酸マグネシウム、硫酸カルシウム、擬ベーマイト、酸化亜鉛、水酸化亜鉛、アルミナ、珪酸アルミナ、珪酸カルシウム、珪酸マグネシウム、酸化ジルコニウム、水酸化ジルコニウム、酸化セリウム、酸化ランタン、酸化イットリウム等が挙げられる。これらの中でも、良好な多孔質構造を形成する観点より、シリカ微粒子、コロイダルシリカ又は擬ベーマイト、アルミナ微粒子が好ましい。
【００９７】
前記無機微粒子は、一次粒子のまま用いても、あるいは二次粒子を形成した状態で使用してもよい。これら無機微粒子の平均一次粒径は２μｍ以下が好ましく、２００ｎｍ以下がより好ましい。特に、平均一次粒径が２０ｎｍ以下のシリカ微粒子、平均一次粒径が２０ｎｍ以下のアルミナ微粒子、あるいは平均細孔半径が２〜１５ｎｍの擬ベーマイトがより好ましい。
【００９８】
シリカ微粒子は、通常その製造法により湿式法粒子と乾式法（気相法）粒子とに大別される。上記湿式法では、ケイ酸塩の酸分解により活性シリカを生成し、これを適度に重合させ凝集沈降させて含水シリカを得る方法が主流である。一方、気相法は、ハロゲン化珪素の高温気相加水分解による方法（火炎加水分解法）、ケイ砂とコークスとを電気炉中でアークによって加熱還元気化し、これを空気で酸化する方法（アーク法）によって無水シリカを得る方法が主流であり、「気相法シリカ」とは該気相法によって得られた無水シリカ微粒子を意味する。本発明に用いるシリカ微粒子としては、特に気相法シリカ微粒子が好ましい。
【００９９】
気相法シリカは、含水シリカと表面のシラノール基の密度、空孔の有無等に相違があり、異なった性質を示すが、空隙率が高い三次元構造を形成するのに適している。この理由は明らかではないが、含水シリカの場合には、微粒子表面におけるシラノール基の密度が５〜８個／ｎｍ²で多く、シリカ微粒子が密に凝集（アグリゲート）し易く、一方、気相法シリカの場合には、微粒子表面におけるシラノール基の密度が２〜３個／ｎｍ²であり少ないことから疎な軟凝集（フロキュレート）となり、その結果、空隙率が高い構造になるものと推定される。
【０１００】
気相法シリカは、比表面積が特に大きいので、インクの吸収性、保持の効率が高く、また、屈折率が低いので、適切な粒子径まで分散をおこなえば受容層に透明性を付与でき、高い色濃度と良好な発色性が得られるという特徴がある。受容層が透明であることは、ＯＨＰ等透明性が必要とされる用途のみならず、フォト光沢紙等の記録用シートに適用する場合でも、高い色濃度と良好な発色性光沢を得る観点で重要である。
【０１０１】
前記気相法シリカの平均一次粒子径としては３０ｎｍ以下が好ましく、２０ｎｍ以下が更に好ましく、１０ｎｍ以下が特に好ましく、３〜１０ｎｍが最も好ましい。上記気相法シリカは、シラノール基による水素結合によって粒子同士が付着しやすいため、平均一次粒子径が３０ｎｍ以下の場合に空隙率の大きい構造を形成することができ、インク吸収特性を効果的に向上させることができる。
【０１０２】
また、シリカ微粒子は、前述の他の無機微粒子と併用してもよい。該他の無機微粒子と上記気相法シリカとを併用する場合、全無機微粒子中の気相法シリカの含有量は、３０質量％以上が好ましく、５０質量％以上がより好ましい。
【０１０３】
本発明に用いる無機微粒子としては、アルミナ微粒子、アルミナ水和物、これらの混合物又は複合物も好ましい。この内、アルミナ水和物は、インクを良く吸収し定着することなどから好ましく、特に、擬ベーマイト（Ａｌ₂Ｏ₃・ｎＨ₂Ｏ）が好ましい。アルミナ水和物は、種々の形態のものを用いることができるが、容易に平滑な層が得られることからゾル状のベーマイトを原料として用いることが好ましい。
【０１０４】
擬ベーマイトの細孔構造については、その平均細孔半径は１〜３０ｎｍが好ましく、２〜１５ｎｍがより好ましい。また、その細孔容積は０．３〜２．０ｃｃ／ｇが好ましく、０．５〜１．５ｃｃ／ｇがより好ましい。ここで、上記細孔半径及び細孔容積の測定は、窒素吸脱着法により測定されるもので、例えば、ガス吸脱着アナライザー（例えば、コールター社製の商品名「オムニソープ３６９」）により測定できる。
また、アルミナ微粒子の中では気相法アルミナ微粒子が比表面積が大きく好ましい。該気相法アルミナの平均一次粒子径としては３０ｎｍ以下が好ましく、２０ｎｍ以下が更に好ましい。
【０１０５】
上述の無機微粒子をインクジェット記録用シートに用いる場合は、例えば、特開平１０−８１０６４号、同１０−１１９４２３号、同１０−１５７２７７号、同１０−２１７６０１号、同１１−３４８４０９号、特開２００１−１３８６２１号、同２０００−４３４０１号、同２０００−２１１２３５号、同２０００−３０９１５７号、同２００１−９６８９７号、同２００１−１３８６２７号、特開平１１−９１２４２号、同８−２０８７号、同８−２０９０号、同８−２０９１号、同８−２０９３号、同８−１７４９９２号、同１１−１９２７７７号、特開２００１−３０１３１４号等公報に開示された態様でも、好ましく用いることができる。
【０１０６】
また、上記無機微粒子の分散性を改善する目的で、該無機微粒子表面をシランカップリング剤で処理してもよい。該シランカップリング剤としては、カップリング処理を行なう部位の他に、有機官能基（例えば、ビニル基、アミノ基、エポキシ基、メルカプト基、クロロ基、アルキル基、フェニル基、エステル基等）を有するものが好ましい。
【０１０７】
−架橋剤−
本発明のインクジェット記録用シートの色材受容層は、微粒子及び水溶性樹脂を含む塗布層が、更に該水溶性樹脂を架橋し得る架橋剤を含み、該架橋剤と水溶性樹脂との架橋反応によって硬化された多孔質層である態様が好ましい。
【０１０８】
上記の水溶性樹脂、特にポリビニルアルコール系樹脂の架橋には、ホウ素化合物が好ましい。該ホウ素化合物としては、例えば、硼砂、硼酸、硼酸塩（例えば、オルト硼酸塩、ＩｎＢＯ₃、ＳｃＢＯ₃、ＹＢＯ₃、ＬａＢＯ₃、Ｍｇ₃(ＢＯ₃)₂、Ｃｏ₃(ＢＯ₃)₂、二硼酸塩（例えば、Ｍｇ₂Ｂ₂Ｏ₅、Ｃｏ₂Ｂ₂Ｏ₅）、メタ硼酸塩（例えば、ＬｉＢＯ₂、Ｃａ(ＢＯ₂)₂、ＮａＢＯ₂、ＫＢＯ₂）、四硼酸塩（例えば、Ｎａ₂Ｂ₄Ｏ₇・１０Ｈ₂Ｏ）、五硼酸塩（例えば、ＫＢ₅Ｏ₈・４Ｈ₂Ｏ、Ｃａ₂Ｂ₆Ｏ₁₁・７Ｈ₂Ｏ、ＣｓＢ₅Ｏ₅）等を挙げることができる。中でも、速やかに架橋反応を起こすことができる点で、硼砂、硼酸、硼酸塩が好ましく、特に硼酸が好ましい。
【０１０９】
上記水溶性樹脂の架橋剤として、ホウ素化合物以外の下記化合物を使用することもできる。
例えば、ホルムアルデヒド、グリオキザール、グルタールアルデヒド等のアルデヒド系化合物；ジアセチル、シクロペンタンジオン等のケトン系化合物；ビス（２−クロロエチル尿素）−２−ヒドロキシ−４，６−ジクロロ−１，３，５−トリアジン、２，４−ジクロロ−６−Ｓ−トリアジン・ナトリウム塩等の活性ハロゲン化合物；ジビニルスルホン酸、１，３−ビニルスルホニル−２−プロパノール、Ｎ，Ｎ’−エチレンビス（ビニルスルホニルアセタミド）、１，３，５−トリアクリロイル−ヘキサヒドロ−Ｓ−トリアジン等の活性ビニル化合物；ジメチロ−ル尿素、メチロールジメチルヒダントイン等のＮ−メチロール化合物；メラミン樹脂（例えば、メチロールメラミン、アルキル化メチロールメラミン）；エポキシ樹脂；
【０１１０】
１，６−ヘキサメチレンジイソシアネート等のイソシアネート系化合物；米国特許明細書第３０１７２８０号、同第２９８３６１１号に記載のアジリジン系化合物；米国特許明細書第３１００７０４号に記載のカルボキシイミド系化合物；グリセロールトリグリシジルエーテル等のエポキシ系化合物；１，６−ヘキサメチレン−Ｎ，Ｎ’−ビスエチレン尿素等のエチレンイミノ系化合物；ムコクロル酸、ムコフェノキシクロル酸等のハロゲン化カルボキシアルデヒド系化合物；２，３−ジヒドロキシジオキサン等のジオキサン系化合物；乳酸チタン、硫酸アルミ、クロム明ばん、カリ明ばん、酢酸ジルコニル、酢酸クロム等の金属含有化合物、テトラエチレンペンタミン等のポリアミン化合物、アジピン酸ジヒドラジド等のヒドラジド化合物、オキサゾリン基を２個以上含有する低分子又はポリマー等である。
上記の架橋剤は、一種単独でも、２種以上を組合わせて用いてもよい。
【０１１１】
架橋硬化は、無機微粒子、カチオン性ポリマー、水溶性樹脂等を含有する塗布液（塗布液Ａ）及び／又は下記塩基性溶液に架橋剤を添加し、かつ、（１）前記塗布液Ａを塗布して塗布層を形成すると同時、又は（２）前記塗布液Ａを塗布して形成される塗布層の乾燥途中であって該塗布層が減率乾燥を示す前のいずれかのときに、ｐＨ８以上の塩基性溶液（塗布液Ｂ）を前記塗布層に付与することにより行うことが好ましい。
【０１１２】
上記架橋剤の付与は、ホウ素化合物を例にすると下記のように行われることが好ましい。即ち、色材受容層が、無機微粒子及び分散剤等を含有する色材受容層用塗布液（塗布液Ａ）を塗布した塗布層を架橋硬化させた層である場合、架橋硬化は、（１）前記塗布液Ａを塗布して塗布層を形成すると同時、（２）前記塗布液Ａを塗布して形成される塗布層の乾燥塗中であって該塗布層が減率乾燥を示す前のいずれかのときに、ｐＨ８以上の塩基性溶液（塗布液Ｂ）を前記塗布層に付与することにより行われる。架橋剤たるホウ素化合物は、塗布液Ａ又は塗布液Ｂのいずれかに含有すればよく、塗布液Ａ及び塗布液Ｂの両方に含有させておいてもよい。
架橋剤の使用量は、層中の水溶性樹脂に対して、１〜５０質量％が好ましく、５〜４０質量％がより好ましい。
【０１１３】
−その他の成分−
本発明のインクジェット記録用シートは、必要に応じて、更に各種の公知の添加剤、例えば紫外線吸収剤、酸化防止剤、蛍光増白剤、モノマー、重合開始剤、重合禁止剤、ニジミ防止剤、防腐剤、粘度安定剤、消泡剤、界面活性剤、帯電防止剤、マット剤、カール防止剤、耐水化剤等を含有することができる。
上述のカチオン性ポリマー（媒染剤）には、紫外線吸剤、酸化防止剤、滲み防止剤などの堅牢性向上剤を併用することが好ましい。
【０１１４】
これら併用してもよい紫外線吸剤、酸化防止剤、ニジミ防止剤としては、アルキル化フェノール性化合物（ヒンダードフェノール性化合物を含む）、アルキルチオメチルフェノール性化合物、ヒドロキノン化合物、アルキル化ヒドロキノン化合物、トコフェロール化合物、チオジフェニルエーテル化合物、２個以上のチオエーテル結合を有する化合物、ビスフェノール性化合物、Ｏ−，Ｎ−及びＳ−ベンジル化合物、ヒドロキシベンジル化合物、トリアジン化合物、ホスホネート化合物、アシルアミノフェノール性化合物、エステル化合物、アミド化合物、アスコルビン酸、アミン系抗酸化剤、２−（２−ヒドロキシフェニル）ベンゾトリアゾール化合物、２−ヒドロキシベンゾフェノン化合物、アクリレート、水溶性又は疎水性の金属塩、有機金属化合物、金属錯体、ヒンダードアミン化合物（ＴＥＭＰＯ化合物を含む）、２−（２−ヒドロキシフェニル）１，３，５，−トリアジン化合物、金属不活性化剤、ホスフィット化合物、ホスホナイト化合物、ヒドロキシアミン化合物、ニトロン化合物、過酸化物スカベンジャー、ポリアミド安定剤、ポリエーテル化合物、塩基性補助安定剤、核剤、ベンゾフラノン化合物、インドリノン化合物、ホスフィン化合物、ポリアミン化合物、チオ尿素化合物、尿素化合物、ヒドラジト化合物、アミジン化合物、糖化合物、ヒドロキシ安息香酸化合物、ジヒドロキシ安息香酸化合物、トリヒドロキシ安息香酸化合物等が挙げられる。
【０１１５】
これらの中でも、アルキル化フェノール性化合物、２個以上のチオエーテル結合を有する化合物、ビスフェノール性化合物、アスコルビン酸、アミン系抗酸化剤、水溶性又は疎水性の金属塩、有機金属化合物、金属錯体、ヒンダードアミン化合物、ポリアミン化合物、チオ尿素化合物、ヒドラジド化合物、ヒドロキシ安息香酸化合物、ジヒドロキシ安息香酸化合物、トリヒドロキシ安息香酸化合物の内少なくても一種を組合せて用いるのが好ましい。
【０１１６】
具体的な化合物例は、特開平１０−１８２６２１号、特開２００１−２６０５１９号、特公平４−３４９５３号、特公平４−３４５１３号、特開平１１−１７０６８６号、特願２００１−１５２２３７号、特公平４−３４５１２、ＥＰ１１３８５０９号、特開昭６０−６７１９０号、特開平７−２７６８０８号、特開２００１−９４８２９号、特開昭４７−１０５３７号公報、同５８−１１１９４２号公報、同５８−２１２８４４号公報、同５９−１９９４５号公報、同５９−４６６４６号公報、同５９−１０９０５５号公報、同６３−５３５４４号公報、特公昭３６−１０４６６号公報、同４２−２６１８７号公報、同４８−３０４９２号公報、同４８−３１２５５号公報、同４８−４１５７２号公報、同４８−５４９６５号公報、同５０−１０７２６号公報、米国特許第２，７１９，０８６号明細書、同３，７０７，３７５号明細書、同３，７５４，９１９号明細書、同４，２２０，７１１号明細書；
【０１１７】
特公昭４５−４６９９号公報、同５４−５３２４号公報、ヨーロッパ公開特許第２２３７３９号公報、同３０９４０１号公報、同３０９４０２号公報、同３１０５５１号公報、同第３１０５５２号公報、同第４５９４１６号公報、ドイツ公開特許第３４３５４４３号公報、特開昭５４−４８５３５号公報、同６０−１０７３８４号公報、同６０−１０７３８３号公報、同６０−１２５４７０号公報、同６０−１２５４７１号公報、同６０−１２５４７２号公報、同６０−２８７４８５号公報、同６０−２８７４８６号公報、同６０−２８７４８７号公報、同６０−２８７４８８号公報、同６１−１６０２８７号公報、同６１−１８５４８３号公報、同６１−２１１０７９号公報、同６２−１４６６７８号公報、同６２−１４６６８０号公報、同６２−１４６６７９号公報、同６２−２８２８８５号公報、同６２−２６２０４７号公報、同６３−０５１１７４号公報、同６３−８９８７７号公報、同６３−８８３８０号公報、同６６−８８３８１号公報、同６３−１１３５３６号公報；
【０１１８】
同６３−１６３３５１号公報、同６３−２０３３７２号公報、同６３−２２４９８９号公報、同６３−２５１２８２号公報、同６３−２６７５９４号公報、同６３−１８２４８４号公報、特開平１−２３９２８２号公報、特開平２−２６２６５４号公報、同２−７１２６２号公報、同３−１２１４４９号公報、同４−２９１６８５号公報、同４−２９１６８４号公報、同５−６１１６６号公報、同５−１１９４４９号公報、同５−１８８６８７号公報、同５−１８８６８６号公報、同５−１１０４９０号公報、同５−１１０８４３７号公報、同５−１７０３６１号公報、特公昭４８−４３２９５号公報、同４８−３３２１２号公報、米国特許第４８１４２６２号明細書、同第４９８０２７５号明細書等に記載のものが挙げられる。
【０１１９】
その他の成分は、１種単独でも２種以上を併用してもよい。その他の成分は、水溶性化、分散化、ポリマー分散、エマルション化、油滴化して添加してもよく、マイクロカプセル中に内包することもできる。その他の成分を添加する場合の添加量としては、０．０１〜１０ｇ／ｍ²が好ましい。
【０１２０】
本発明において、色材受容層用塗布液は界面活性剤を含有しているのが好ましい。該界面活性剤としてはカチオン系、アニオン系、ノニオン系、両性、フッ素系、シリコン系界面活性剤のいずれも使用可能である。
前記ノニオン系界面活性剤としては、ポリオキシアルキレンアルキルエーテル及びポリオキシアルキレンアルキルフェニルエーテル類（例えば、ジエチレングリコールモノエチルエーテル、ジエチレングリーコールジエチルエーテル、ポリオキシエチレンラウリルエーテル、ポリオキシエチレンステアリルエーテル、ポリオキシエチレンノニルフェニルエーテル等）、オキシエチレン・オキシプロピレンブロックコポリマー、ソルビタン脂肪酸エステル類（例えば、ソルビタンモノラウレート、ソルビタンモノオレート、ソルビタントリオレート等）、ポリオキシエチレンソルビタン脂肪酸エステル類（例えば、ポリオキシエチレンソルビタンモノラウレート、ポリオキシエチレンソルビタンモノオレート、ポリオキシエチレンソルビタントリオレート等）、ポリオキシエチレンソルビトール脂肪酸エステル類（例えば、テトラオレイン酸ポリオキシエチレンソルビット等）、グリセリン脂肪酸エステル類（例えば、グリセロールモノオレート等）、ポリオキシエチレングリセリン脂肪酸エステル類（モノステアリン酸ポリオキシエチレングリセリン、モノオレイン酸ポリオキシエチレングリセリン等）、ポリオキシエチレン脂肪酸エステル類（ポリエチレングリコールモノラウレート、ポリエチレングリコールモノオレート等）、ポリオキシエチレンアルキルアミン、アセチレングリコール類（例えば、２，４，７，９−テトラメチル−５−デシン−４，７−ジオール、及び該ジオールのエチレンオキサイド付加物、プロピレンオキサイド付加物等）等が挙げられ、ポリオキシアルキレンアルキルエーテル類が好ましい。該ノニオン系界面活性剤は、塗布液Ａ及び塗布液Ｂにおいて使用することができる。また、前記ノニオン系界面活性剤は、単独で使用してもよく、２種以上を併用してもよい。
【０１２１】
前記両性界面活性剤としては、アミノ酸型、カルボキシアンモニウムベタイン型、スルホンアンモニウムベタイン型、アンモニウム硫酸エステルベタイン型、イミダゾリウムベタイン型等が挙げられ、例えば、米国特許第３，８４３，３６８号明細書、特開昭５９−４９５３５号公報、同６３−２３６５４６号公報、特開平５−３０３２０５号公報、同８−２６２７４２号公報、同１０−２８２６１９号公報等に記載されているものを好適に使用できる。該両性界面活性剤としては、アミノ酸型両性界面活性剤が好ましく、該アミノ酸型両性界面活性剤としては、特開平５−３０３２０５号公報に記載されているように、例えば、アミノ酸（グリシン、グルタミン酸、ヒスチジン酸等）から誘導体化されたものであり、長鎖のアシル基を導入したＮ−アミノアシル酸及びその塩が挙げられる。前記両性界面活性剤は１種で使用してもよく、２種以上を併用してもよい。
【０１２２】
前記アニオン系界面活性剤としては、脂肪酸塩（例えばステアリン酸ソーダ、オレイン酸カリ）、アルキル硫酸エステル塩（例えばラウリル硫酸ナトリウム、ラウリル硫酸トリエタノールアミン）、スルホン酸塩（例えばドデシルベンゼンスルホン酸ナトリウム）、アルキルスルホコハク酸塩（例えばジオクチルスルホコハク酸ナトリウム）、アルキルジフェニルエーテルジスルホン酸塩、アルキルリン酸塩等が挙げられる。
前記カチオン系界面活性剤としては、アルキルアミン塩、第４級アンモニウム塩、ピリジニウム塩、イミダゾリウム塩などが挙げられる。
【０１２３】
前記フッ素系界面活性剤としては、電解フッ素化、テロメリゼーション、オリゴメリゼーションなどの方法を用いてパーフルオロアルキル基を持つ中間体を経て誘導される化合物が挙げられる。例えば、パーフルオロアルキルスルホン酸塩、パーフルオロアルキルカルボン酸塩、パーフルオロアルキルエチレンオキサイド付加物、パーフルオロアルキルトリアルキルアンモニウム塩、パーフルオロアルキル基含有オリゴマー、パーフルオロアルキルリン酸エステルなどが挙げられる。
【０１２４】
前記シリコン系界面活性剤としては、有機基で変性したシリコンオイルが好ましく、シロキサン構造の側鎖を有機基で変性した構造、両末端を変性した構造、片末端を変性した構造をとり得る。有機基変性として、アミノ変性、ポリエーテル変性、エポキシ変性、カルボキシル変性、カルビノール変性、アルキル変性、アラルキル変性、フェノール変性、フッ素変性等が挙げられる。
【０１２５】
本発明で界面活性剤の含有量としては、色材受容層用塗布液に対して０．００１〜２．０％が好ましく、０．０１〜１．０％がより好ましい。また、色材受容層用塗布液として２液以上を用いて塗布を行なう場合には、それぞれの塗布液に界面活性剤を添加するのが好ましい。
【０１２６】
本発明において、色材受容層はカール防止用に高沸点有機溶剤を含有するのが好ましい。前記高沸点有機溶剤は常圧で沸点が１５０℃以上の有機化合物で、水溶性又は疎水性の化合物である。これらは、室温で液体でも固体でもよく、低分子でも高分子でもよい。
具体的には、芳香族カルボン酸エステル類（例えばフタル酸ジブチル、フタル酸ジフェニル、安息香酸フェニルなど）、脂肪族カルボン酸エステル類（例えばアジピン酸ジオクチル、セバシン酸ジブチル、ステアリン酸メチル、マレイン酸ジブチル、フマル酸ジブチル、アセチルクエン酸トリエチルなど）、リン酸エステル類（例えばリン酸トリオクチル、リン酸トリクレジルなど）、エポキシ類（例えばエポキシ化大豆油、エポキシ化脂肪酸メチルなど）、アルコール類（例えば、ステアリルアルコール、エチレングリコール、プロピレングリコール、ジエチレングリコール、トリエチレングリコール、グリセリン、ジエチレングリコールモノブチルエーテル（ＤＥＧＭＢＥ）、トリエチレングリコールモノブチルエーテル、グリセリンモノメチルエーテル、１，２，３−ブタントリオール、１，２，４−ブタントリオール、１，２，４−ペンタントリオール、１，２，６−ヘキサントリオール、チオジグリコール、トリエタノールアミン、ポリエチレングリコールなど）、植物油（例えば大豆油、ヒマワリ油など）高級脂肪族カルボン酸（例えばリノール酸、オレイン酸など）等が挙げられる。
【０１２７】
（支持体）
支持体としては、プラスチック等の透明材料よりなる透明支持体、紙等の不透明材料からなる不透明支持体のいずれをも使用できる。色材受容層の透明性を生かす上では、透明支持体又は高光沢性の不透明支持体を用いることが好ましい。
【０１２８】
前記透明支持体に使用可能な材料としては、透明性で、ＯＨＰやバックライトディスプレイで使用される時の輻射熱に耐え得る性質を有する材料が好ましい。該材料としては、例えば、ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル類；ポリスルホン、ポリフェニレンオキサイド、ポリイミド、ポリカーボネート、ポリアミド等を挙げることができる。中でも、ポリエステル類が好ましく、特にポリエチレンテレフタレートが好ましい。
前記透明支持体の厚みとしては、特に制限はないが、取り扱い易い点で、５０〜２００μｍが好ましい。
【０１２９】
高光沢性の不透明支持体としては、色材受容層の設けられる側の表面が４０％以上の光沢度を有するものが好ましい。前記光沢度は、ＪＩＳ Ｐ−８１４２（紙及び板紙の７５度鏡面光沢度試験方法）に記載の方法に従って求められる値である。具体的には、下記支持体が挙げられる。
【０１３０】
例えば、アート紙、コート紙、キャストコート紙、銀塩写真用支持体等に使用されるバライタ紙等の高光沢性の紙支持体；ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル類、ニトロセルロース，セルロースアセテート，セルロースアセテートブチレート等のセルロースエステル類、ポリスルホン、ポリフェニレンオキサイド、ポリイミド、ポリカーボネート、ポリアミド等のプラスチックフィルムに白色顔料等を含有させて不透明にした（表面カレンダー処理が施されていてもよい。）高光沢性のフィルム；或いは、前記各種紙支持体、前記透明支持体若しくは白色顔料等を含有する高光沢性のフィルムの表面に、白色顔料を含有若しくは含有しないポリオレフィンの被覆層が設けられた支持体等が挙げられる。
白色顔料含有発泡ポリエステルフィルム（例えば、ポリオレフィン微粒子を含有させ、延伸により空隙を形成した発泡ＰＥＴ）も好適に挙げることができる。更に銀塩写真用印画紙に用いられるレジンコート紙も好適である。
【０１３１】
前記不透明支持体の厚みについても特に制限はないが、取り扱い性の点で、５０〜３００μｍが好ましい。
【０１３２】
また、前記支持体の表面には、濡れ特性及び接着性を改善するために、コロナ放電処理、グロー放電処理、火炎処理、紫外線照射処理等を施したものを使用してもよい。
【０１３３】
次に、前記レジンコート紙に用いられる原紙について詳述する。
前記原紙としては、木材パルプを主原料とし、必要に応じて木材パルプに加えてポリプロピレンなどの合成パルプ、あるいはナイロンやポリエステルなどの合成繊維を用いて抄紙される。前記木材パルプとしては、ＬＢＫＰ、ＬＢＳＰ、ＮＢＫＰ、ＮＢＳＰ、ＬＤＰ、ＮＤＰ、ＬＵＫＰ、ＮＵＫＰのいずれも用いることができるが、短繊維分の多いＬＢＫＰ、ＮＢＳＰ、ＬＢＳＰ、ＮＤＰ、ＬＤＰをより多く用いることが好ましい。
但し、ＬＢＳＰ及び／又はＬＤＰの比率としては、１０質量％以上、７０質量％以下が好ましい。
【０１３４】
前記パルプは、不純物の少ない化学パルプ（硫酸塩パルプや亜硫酸パルプ）が好ましく用いられ、漂白処理を行なって白色度を向上させたパルプも有用である。
【０１３５】
原紙中には、高級脂肪酸、アルキルケテンダイマー等のサイズ剤、炭酸カルシウム、タルク、酸化チタン等の白色顔料、スターチ、ポリアクリルアミド、ポリビニルアルコール等の紙力増強剤、蛍光増白剤、ポリエチレングリコール類等の水分保持剤、分散剤、４級アンモニウム等の柔軟化剤などを適宜添加することができる。
【０１３６】
抄紙に使用するパルプの濾水度としては、ＣＳＦの規定で２００〜５００ｍｌが好ましく、また、叩解後の繊維長が、ＪＩＳ Ｐ−８２０７に規定される２４メッシュ残分質量％と４２メッシュ残分の質量％との和が３０〜７０％が好ましい。尚、４メッシュ残分の質量％は２０質量％以下であることが好ましい。
【０１３７】
原紙の坪量としては、３０〜２５０ｇが好ましく、特に５０〜２００ｇが好ましい。原紙の厚さとしては、４０〜２５０μｍが好ましい。原紙は、抄紙段階又は抄紙後にカレンダー処理して高平滑性を与えることもできる。原紙密度は０．７〜１．２ｇ／ｍ²（ＪＩＳ Ｐ−８１１８）が一般的である。
更に、原紙剛度としては、ＪＩＳ Ｐ−８１４３に規定される条件で２０〜２００ｇが好ましい。
【０１３８】
原紙表面には表面サイズ剤を塗布してもよく、表面サイズ剤としては、前記原紙中添加できるサイズと同様のサイズ剤を使用できる。
原紙のｐＨは、ＪＩＳ Ｐ−８１１３で規定された熱水抽出法により測定された場合、５〜９であることが好ましい。
【０１３９】
原紙表面及び裏面を被覆するポリエチレンは、主として低密度のポリエチレン（ＬＤＰＥ）及び／又は高密度のポリエチレン（ＨＤＰＥ）であるが、他のＬＬＤＰＥやポリプロピレン等も一部使用することができる。
【０１４０】
特に、色材受容層を形成する側のポリエチレン層は、写真用印画紙で広く行なわれているように、ルチル又はアナターゼ型の酸化チタン、蛍光増白剤、群青をポリエチレン中に添加し、不透明度、白色度及び色相を改良したものが好ましい。ここで、酸化チタン含有量としては、ポリエチレンに対して、概ね３〜２０質量％が好ましく、４〜１３質量％がより好ましい。ポリエチレン層の厚みは特に限定はないが、表裏面層とも１０〜５０μｍが好適である。さらにポリエチレン層上に色材受容層との密着性を付与するために下塗り層を設けることもできる。該下塗り層としては、水性ポリエステル、ゼラチン、ＰＶＡが好ましい。また、該下塗り層の厚みとしては、０．０１〜５μｍが好ましい。
【０１４１】
ポリエチレン被覆紙は、光沢紙として用いることも、また、ポリエチレンを原紙表面上に溶融押し出してコーティングする際に、いわゆる型付け処理を行なって通常の写真印画紙で得られるようなマット面や絹目面を形成したものも使用できる。
【０１４２】
支持体にはバックコート層を設けることもでき、このバックコート層に添加可能な成分としては、白色顔料や水性バインダー、その他の成分が挙げられる。
バックコート層に含有される白色顔料としては、例えば、軽質炭酸カルシウム、重質炭酸カルシウム、カオリン、タルク、硫酸カルシウム、硫酸バリウム、二酸化チタン、酸化亜鉛、硫化亜鉛、炭酸亜鉛、サチンホワイト、珪酸アルミニウム、珪藻土、珪酸カルシウム、珪酸マグネシウム、合成非晶質シリカ、コロイダルシリカ、コロイダルアルミナ、擬ベーマイト、水酸化アルミニウム、アルミナ、リトポン、ゼオライト、加水ハロイサイト、炭酸マグネシウム、水酸化マグネシウム等の白色無機顔料、スチレン系プラスチックピグメント、アクリル系プラスチックピグメント、ポリエチレン、マイクロカプセル、尿素樹脂、メラミン樹脂等の有機顔料等が挙げられる。
【０１４３】
バックコート層に用いられる水性バインダーとしては、例えば、スチレン／マレイン酸塩共重合体、スチレン／アクリル酸塩共重合体、ポリビニルアルコール、シラノール変性ポリビニルアルコール、澱粉、カチオン化澱粉、カゼイン、ゼラチン、カルボキシメチルセルロース、ヒドロキシエチルセルロース、ポリビニルピロリドン等の水溶性高分子、スチレンブタジエンラテックス、アクリルエマルジョン等の水分散性高分子等が挙げられる。
バックコート層に含有されるその他の成分としては、消泡剤、抑泡剤、染料、蛍光増白剤、防腐剤、耐水化剤等が挙げられる。
【０１４４】
【実施例】
以下、実施例により本発明を具体的に説明するが、本発明はこれらの実施例に限定されるものではない。尚、実施例中の「部」及び「％」は、特に断らない限り「質量部」及び「質量％」を表し、「分子量」は「重量平均分子量」を表す。
【０１４５】
（支持体の作製）
ＬＢＫＰ１００部からなる木材パルプをダブルディスクリファイナーによりカナディアンフリーネス３００ｍｌまで叩解し、エポキシ化ベヘン酸アミド０．５部、アニオンポリアクリルアミド１．０部、ポリアミドポリアミンエピクロルヒドリン０．１部、カチオンポリアクリルアミド０．５部を、いずれもパルプに対する絶乾質量比で添加し、長網抄紙機により秤量し１７０ｇ／ｍ²の原紙を抄造した。
【０１４６】
上記原紙の表面サイズを調整するため、ポリビニルアルコール４％水溶液に蛍光増白剤（住友化学工業（株）製の「Ｗｈｉｔｅｘ ＢＢ」）を０．０４％添加し、これを絶乾質量換算で０．５ｇ／ｍ²となるように上記原紙に含浸させ、乾燥した後、更にキャレンダー処理を施して密度１．０５ｇ／ｃｃに調整された基紙を得た。
【０１４７】
得られた基紙のワイヤー面（裏面）側にコロナ放電処理を行なった後、溶融押出機を用いて高密度ポリエチレンを厚さ１９μｍとなるようにコーティングし、マット面からなる樹脂層を形成した（以下、樹脂層面を「裏面」と称する。）。この裏面側の樹脂層に更にコロナ放電処理を施し、その後、帯電防止剤として、酸化アルミニウム（日産化学工業（株）製の「アルミナゾル１００」）と二酸化ケイ素（日産化学工業（株）製の「スノーテックスＯ」）とを１：２の質量比で水に分散した分散液を、乾燥質量が０．２ｇ／ｍ²となるように塗布した。
【０１４８】
更に、樹脂層の設けられていない側のフェルト面（オモテ面）側にコロナ放電処理を施した後、アナターゼ型二酸化チタン１０％、微量の群青、及び蛍光増白剤０．０１％（対ポリエチレン）を含有し、ＭＦＲ（メルトフローレート）３．８の低密度ポリエチレンを、溶融押出機を用いて、厚み２９μｍとなるように押し出し、高光沢な熱可塑性樹脂層を基紙の表面側に形成し（以下、この高光沢面を「オモテ面」と称する。）、支持体とした。
【０１４９】
［実施例１〜３、比較例１〜４］
（色材受容層用塗布液Ａの調製）
下記組成中の▲１▼気相法シリカ微粒子と▲２▼イオン交換水と▲３▼下記表１に示す分散剤を混合し、高速回転式コロイドミル（エム・テクニック（株）製の「クレアミックス」）を用いて回転数１００００ｒｐｍで２０分間かけて分散させて、無機微粒子分散液を調製した後、この無機微粒子分散液に、下記▲４▼ポリビニルアルコールと▲５▼ホウ酸と▲６▼ポリオキシエチレンラウリルエーテルと▲７▼イオン交換水を含む溶液を加え、更に回転数１００００ｒｐｍで２０分間かけて再度分散を行ない、色材受容層用塗布液Ａを調製した。
シリカ微粒子と水溶性樹脂との質量比（ＰＢ比＝▲１▼：▲４▼）は、４．５：１であり、色材受容層用塗布液ＡのｐＨは、３．５で酸性を示した。
【０１５０】
<色材受容層塗布液Ａの組成>
▲１▼気相法シリカ微粒子（無機微粒子） …１０．０部
（レオロシールＱＳ３０、平均一次粒子径７ｎｍ、（株）トクヤマ製）
▲２▼イオン交換水 …５１．７部
▲３▼下記分散剤（下記表１参照）
▲４▼ポリビニルアルコール（水溶性樹脂）８％水溶液 …２７．８部
（ＰＶＡ１２４、鹸化度９８．５％、重合度２４００、（株）クラレ製）
▲５▼ホウ酸（架橋剤） … ０．４部
▲６▼ポリオキシエチレンラウリルエーテル（界面活性剤） … １．２部
（エマルゲン１０９Ｐ（１０％水溶液）、ＨＬＢ値１３．６、花王（株）製）
▲７▼イオン交換水 …３３．０部
【０１５１】
【表１】

【０１５２】
（インクジェット記録用シートの作製）
上記支持体のオモテ面にコロナ放電処理を行なった後、上記から得た色材受容層用塗布液Ａを、支持体のオモテ面にエクストルージョンダイコーターを用いて２００ｍｌ／ｍ²の塗布量で塗布し（塗布工程）、熱風乾燥機にて８０℃（風速３〜８ｍ／秒）で塗布層の固形分濃度が２０％になるまで乾燥させた。この塗布層は、この期間は恒率乾燥を示した。その直後、下記組成の媒染剤溶液Ｂに３０秒間浸漬して該塗布層上にその２０ｇ／ｍ²を付着させ（媒染剤溶液を付与する工程）、更に８０℃下で１０分間乾燥させた（乾燥工程）。これにより、乾燥膜厚３２μｍの色材受容層が設けられた本発明のインクジェット記録用シートを作製した。
【０１５３】
<媒染剤溶液Ｂの組成>
▲１▼硼酸（架橋剤） … ０．６５部
▲２▼ポリアリルアミン「ＰＡＡ−１０Ｃ」１０％水溶液 …２５部
（媒染剤、日東紡（株）製）
▲３▼イオン交換水 …５９．７部
▲４▼塩化アンモニウム（表面ｐＨ調製剤） … ０．８部
▲５▼ポリオキシエチレンラウリルエーテル（界面活性剤） …１０部
（エマルゲン１０９Ｐ、２％水溶液、ＨＬＢ値１３．６、花王（株）製）
▲６▼メガファック「Ｆ１４０５」１０％水溶液 … ２．０部
（フッ素系界面活性剤、大日本インキ化学工業（株）製）
【０１５４】
（評価）
(1) 色材受容層用塗布液Ａの液安定性
各実施例及び比較例において調製した各々の色材受容層用塗布液Ａについて、調製直後、並びに調製後に３０℃環境下で７日間保管した後、における液温３０℃での粘度をＢ型粘度計によって測定した。測定結果は下記表２に示す。
【０１５５】
(2)経時ニジミ
各実施例及び比較例において得た色材受容層用塗布液Ａを用いて作製した各インクジェット記録用シートについて、インクジェットプリンター（セイコーエプソン（株）製の「ＰＭ−９００Ｃ」）を用いて、マゼンタインクとブラックインクとを隣り合わせにした格子状の線状パターン（線幅０．２８ｍｍ）を印画し、Ｘ−ｒｉｔｅ社製の「Ｘ−ｒｉｔｅ３１０ＴＲ」によってビジュアル濃度Ｄ¹を測定した。引き続き、印画後３時間放置した後、温度４０℃相対湿度９０％の恒温恒湿槽に１日間保管した後、再度上記同様にしてビジュアル濃度Ｄ²を測定し、その濃度差ΔＯＤ（＝Ｄ¹−Ｄ²）によって経時ニジミを評価した。この濃度差（ΔＯＤ）の値が小さい程、経時ニジミの発生は抑制されていることを示す。評価結果は下記表２に示す。
【０１５６】
【表２】

【０１５７】
上記表２の結果から、色材受容層用塗布液を調製するにあたって、無機微粒子を重量平均分子量の異なる二種のカチオン性ポリマー（分散剤）を用いて分散し無機微粒子分散液とした実施例１〜３では、調製された色材受容層用塗布液は経時で大きく増粘することなく安定に保持することができ、液安定性が良好であることを示した。また、これらの色材受容層用塗布液を用いて作製したインクジェット記録用シートは、いずれもインク吸収性等のインク受容性が良好であると同時に、画像の経時ニジミも抑制された。
一方、無機微粒子の分散に一種の分散剤しか混合しなかった比較例では、いずれも粘度が高く分散性が必ずしも充分でなく、しかも経時で増粘し分散性は低下してしまった。また、これらを用いて得たインクジェット記録用シートは、特に経時ニジミの点で劣っていた。このように、比較例においては、無機微粒子の分散安定性を向上し、同時に経時ニジミとも良化することはできなかった。
【０１５８】
【発明の効果】
本発明によれば、色材受容層形成用の塗布液の調製にあたって、無機微粒子を分散した無機微粒子分散液の安定性を良化し、歩留りを抑えてインクジェット記録用シートの生産性を向上させることができるインクジェット記録用シートの製造方法を提供することができる。また、
本発明によれば、上記本発明のインクジェット記録用シートの製造方法により得られ、良好なインク吸収性を持ちながら、経時でのニジミがなく、かつ生産適性に優れたインクジェット記録用シートを提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording using a liquid ink such as a water-based ink (using a dye or pigment as a coloring material) and an oil-based ink, or a solid ink which is solid at room temperature and melted and liquefied for printing. In particular, the present invention relates to an ink jet recording sheet having excellent ink receiving performance, improved aging blurring, and good production suitability, and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, with the rapid development of the information technology (IT) industry, various information processing systems have been developed, and recording methods and recording apparatuses suitable for the information processing systems have been developed and put into practical use. Among these recording methods, the inkjet recording method is capable of recording on a variety of recording materials, has advantages such as being relatively inexpensive and compact in hardware (device), and excellent in quietness. It has also been widely used for so-called home use.
[0003]
In addition, with the recent increase in resolution of inkjet printers, it has become possible to obtain so-called photographic-like high-quality recorded matter. With the progress of such hardware (devices), recording for inkjet recording has become possible. Various seats have been developed.
The characteristics required for this recording sheet for ink jet recording are generally (1) fast drying (high ink absorption speed), and (2) ink dot diameter is appropriate and uniform. (No blurring), (3) good graininess, (4) high dot roundness, (5) high color density, (6) high chroma (dullness) (7) The water resistance, light resistance, and ozone resistance of the print portion are good, (8) the whiteness of the recording sheet is high, and (9) the storage stability of the recording sheet is good ( (10) it is hard to deform and has good dimensional stability (curl is sufficiently small), and (11) good hard running performance.
Furthermore, in the use of photo glossy paper used for the purpose of obtaining so-called photographic-like high-quality recorded matter, in addition to the above properties, gloss, surface smoothness, photographic paper-like texture similar to silver salt photography, etc. Is also required.
[0004]
In recent years, an ink jet recording sheet having a porous structure in a colorant receiving layer has been developed and put into practical use for the purpose of improving the various properties described above. Such an ink jet recording sheet has a porous structure, and thus has excellent ink receptivity (fast drying property) and high gloss. For example, Japanese Patent Application Laid-Open Nos. 10-119423 and 10-217601 propose an ink jet recording sheet containing fine inorganic pigment particles and a water-soluble resin and having a colorant receiving layer having a high porosity. Yes. These recording sheets, particularly ink jet recording sheets provided with a colorant-receiving layer having a porous structure using silica as inorganic pigment fine particles are excellent in ink absorptivity and can form high-resolution images due to their constitution. It has ink receiving performance and can exhibit high gloss.
[0005]
In addition, in the case of ink jet recording, in order to obtain a fine image, it is required that liquid ink is absorbed quickly and there is no ink bleeding or ink accumulation. In order to solve these points, various proposals have been conventionally made.
For example, JP-A-57-14091 and JP-A-61-19389 propose a recording sheet comprising a transparent support and a transparent layer of colloidal silica and a water-soluble resin provided thereon. Has been. However, since this transparent layer has too large colloidal silica particles and the amount of the water-soluble resin is too large, a sufficiently high porosity cannot be obtained. Therefore, the recording sheet exhibits a sufficiently high ink absorption rate. There is a problem that it is difficult.
[0006]
JP-A-2-276670 and JP-A-3-281383 disclose a recording sheet having a colorant-receiving layer having pores formed from pseudoboehmite fine particles. Surely, according to this recording sheet, although the ink absorptivity is improved, it has been found from the examination results that a sufficiently high transparency cannot be obtained because the refractive index is as high as 1.65.
[0007]
Further, JP-A-61-53598 discloses a recording sheet comprising a support, a synthetic silica provided thereon, fine particles having a refractive index of 1.44 to 1.55, and a transparent layer comprising a water-soluble resin. Is disclosed. Synthetic silica usually has a primary particle size exceeding 10 nm, and the secondary particles have a particle size of several hundred nm. Such secondary particles are likely to scatter light, and thus a recording sheet containing such particles does not exhibit a sufficiently high light transmittance. Furthermore, since the transparent layer has a large number of secondary particles because of the large secondary particles, it is not possible to sufficiently prevent the occurrence of ink bleeding or ink accumulation.
[0008]
On the other hand, Japanese Patent Application Laid-Open No. 7-276789 proposes a recording sheet in which a colorant receiving layer having a high porosity three-dimensional structure formed from inorganic fine particles and a water-soluble resin is provided on a transparent support. ing. With this configuration, it is said that the above-described ink absorbability and suppression of ink bleeding are sufficient, and an image with high resolution can be obtained. Japanese Patent Application Laid-Open No. 11-115308 discloses that a colorant-receiving layer is formed by applying a coating liquid containing inorganic fine particles and a water-soluble resin onto a support, and at the same time or at the same time as the coating, A recording sheet is proposed in which a solution containing a crosslinking agent capable of crosslinking the water-soluble resin is applied and cured by a method such as coating while the speed is exhibited (before the reduced drying speed is exhibited). Has been. It is described that by this method, liquid ink can be absorbed quickly and a fine image free from ink bleeding or ink accumulation can be obtained.
However, although some of these effects are recognized to some extent in the ink absorptivity and the suppression of bleeding in ink jet recording, the effects are not always sufficient, and further improvements have been desired.
[0009]
On the other hand, an ink jet recording sheet is prepared by preparing a coating solution for forming a colorant receiving layer using an inorganic fine particle dispersion in which inorganic fine particles are dispersed in an aqueous solvent in advance, and then applying the coating solution on a support. And can be manufactured by forming a colorant receiving layer. However, if the dispersion stability after the preparation of the inorganic fine particle dispersion is insufficient, the liquid stability (dispersibility, viscosity) of the coating liquid for forming the colorant receiving layer that is finally prepared also decreases. In addition, the ink receiving performance including the ink absorbability of the formed colorant receiving layer is not uniform, the surface gloss, the resolution of the formed image, the color density, etc. are impaired. It becomes a cause. Moreover, when the liquid stability of the prepared inorganic fine particle dispersion is low, not only the productivity is lowered but also the yield is deteriorated.
[0010]
[Problems to be solved by the invention]
As described above, in the ink jet recording sheet in which the color material-receiving layer is provided by coating the support material with the color material-receiving layer coating liquid containing the inorganic fine particle dispersion in which the inorganic fine particles are dispersed. In the present situation, there is no established technology that can improve productivity by preventing performance degradation and yield due to the liquid stability of the ink. There remains room for further improvement in terms of absorbency and resistance to aging blur after image formation.
[0011]
The present invention has been made in view of the above problems, and in the preparation of a coating liquid for forming a colorant receiving layer, the stability of an inorganic fine particle dispersion in which inorganic fine particles are dispersed is improved, and the yield is suppressed. Providing a method for producing an inkjet recording sheet capable of improving the productivity of the inkjet recording sheet, obtained by the method for producing an inkjet recording sheet, and having good ink absorbability, over time. An object of the present invention is to provide an ink jet recording sheet which is free from blurring and excellent in production suitability, and to achieve the object.
[0012]
[Means for Solving the Problems]
  Means for solving the above-mentioned problems are as follows.
  <1> In a method for producing an ink jet recording sheet, a coating material for a colorant receiving layer containing an inorganic fine particle dispersion in which inorganic fine particles are dispersed is applied on a support to form a colorant receiving layer. ,A cationic polymer having a weight average molecular weight of 2,000 to 15,000 and a cationic polymer having a weight average molecular weight of 20,000 to 50,000An inorganic fine particle dispersion is prepared by mixing and dispersing with at least two kinds of cationic polymers, and a water-soluble resin and a crosslinking agent for crosslinking the water-soluble resin are further added to the prepared inorganic fine particle dispersion. This is a method for producing an inkjet recording sheet.
[0013]
  <2> At least two of the cationic polymers are polydimethyldiallylammonium chloride and polymonomethyldiallylammonium chloride<1>The method for producing an inkjet recording sheet described in 1.
[0014]
  <3<1> The mixing amount of each kind of the cationic polymer is 10% by mass or more based on the total mass of all the cationic polymers to be mixed.Or <2>The method for producing an inkjet recording sheet described in 1.
  <4>Small<1> to <<, wherein the total mixing amount of at least two kinds of cationic polymers is 3 to 8% by mass with respect to the mixing mass of the inorganic fine particles.3The method for producing an inkjet recording sheet according to any one of the above.
  <5> <1> to <4The ink-jet recording sheet obtained by the method for producing an ink-jet recording sheet according to any one of the above.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing an inkjet recording sheet of the present invention is characterized in that inorganic fine particles are mixed and dispersed with at least two kinds of dispersants having different weight average molecular weights. Hereinafter, the manufacturing method of the ink jet recording sheet of the present invention will be described in detail, and the ink jet recording sheet obtained by this manufacturing method will be described in detail through the description.
[0016]
In the method for producing an inkjet recording sheet of the present invention, at least one colorant receiving layer is formed by applying a coating material for a colorant receiving layer containing an inorganic fine particle dispersion in which inorganic fine particles are dispersed on a support. To do. At this time, the inorganic fine particle dispersion is prepared by mixing and dispersing the inorganic fine particles with at least two kinds of cationic polymers (dispersing agents) having different weight average molecular weights.
[0017]
  In the present invention, in the process of dispersing the inorganic fine particles,A cationic polymer having a weight average molecular weight of 2,000 to 15000 and a cationic polymer having a weight average molecular weight of 20,000 to 50,000,Dispersing inorganic fine particles in a system that uses at least two kinds of cationic polymers having different weight average molecular weights in combination improves the dispersion stability of inorganic fine particles in aqueous solvents and prevents non-uniformity and thickening of the liquid. be able to. As a result, the liquid stability such as dispersibility, uniformity, viscosity, etc. of the coating material for forming the colorant receiving layer (hereinafter also referred to as coating material for the colorant receiving layer) to be finally prepared can be improved and supported. It is possible to prevent aging of the image formed on the colorant receiving layer on the body.
[0018]
  The colorant receiving layer according to the present invention includes, for example, at least inorganic fine particles andA cationic polymer having a weight average molecular weight of 2,000 to 15,000 and a cationic polymer having a weight average molecular weight of 20,000 to 50,000An inorganic fine particle dispersion containing at least two kinds of cationic polymers (dispersing agents) is prepared, and this inorganic fine particle dispersion (preferably, a water-soluble resin, a mordant, a surfactant, etc. are further added thereto. A coating solution (coloring material-receiving layer coating solution) comprising a coating layer is formed on the support surface to form a coating layer, and a crosslinking agent is added to the coating solution and / or the following basic solution, and ( 1) Either at the same time when the coating solution is applied to form a coating layer, or (2) either during the drying of the coating layer formed by applying the coating solution and before the coating layer exhibits reduced-rate drying. At that time, it can be suitably formed by a method (Wet-on-Wet method) in which a basic solution having a pH of 8 or more is applied to the coating layer and the coating layer is crosslinked and cured. The details of each component contained in the coating solution and the basic solution will be described later.
[0019]
At this time, the crosslinking agent is capable of crosslinking the water-soluble resin, and is preferably contained in at least one or both of the coating solution and the basic solution. Providing the colorant-receiving layer crosslinked and cured in this manner is preferable from the viewpoints of ink absorbability and prevention of film cracking.
[0020]
The inorganic fine particle dispersion is prepared by preparing an aqueous dispersion of inorganic fine particles (for example, a vapor phase silica aqueous dispersion) in advance, and adding the aqueous dispersion to an aqueous dispersant solution containing a cationic polymer. Alternatively, an aqueous dispersant solution containing a cationic polymer may be added to the aqueous dispersion, or the inorganic fine particles and the cationic polymer may be mixed simultaneously with the solvent. Further, instead of the vapor phase silica aqueous dispersion, powder vapor phase silica can be used to add to the aqueous dispersant solution as described above.
[0021]
The inorganic fine particle dispersion contains at least two kinds of cationic polymers having different weight average molecular weights as a dispersant. Three or more kinds of cationic polymers may be contained, and it is only necessary that two kinds of the cationic polymers have different weight average molecular weights. If the weight average molecular weight is different in at least two kinds, the liquid stability of the prepared inorganic fine particle dispersion and the coating material for the colorant receiving layer can be improved, the yield is reduced, and the productivity is improved. Further, it is possible to prevent aging blurring of the formed image.
[0022]
Among the above, a combination in which one kind of weight average molecular weight of the plurality of cationic polymers is 2000 to 15000 and another kind of weight average molecular weight is 20000 to 50000 is preferable. By combining in the above range, the liquid stability can be further improved.
[0023]
When the cationic polymer is mixed with the inorganic fine particles, the mixing amount of one kind of cationic polymer is preferably 10% by mass or more, more preferably 20 to 50% by mass with respect to the total mass of all the cationic polymers to be mixed. preferable.
When the mixing amount of each kind is less than 10% by mass, the effect of the combined use, that is, the effect of improving the liquid stability of the inorganic fine particle dispersion and the colorant-receiving layer coating liquid may not be obtained.
[0024]
The total mixing amount of at least two kinds of cationic polymers having different weight average molecular weights is preferably 3 to 8% by mass and more preferably 4 to 6% by mass with respect to the mixing mass of the inorganic fine particles. When the total mixing amount is less than 3% by mass, the dispersibility of the prepared inorganic fine particle dispersion and the colorant-receiving layer coating solution with time decreases, and the liquid stability decreases due to thickening and the like. If it exceeds 8% by mass, the image quality and ink bleeding may be adversely affected.
[0025]
When inorganic fine particles and a dispersant are mixed and dispersed, the mixed liquid after mixing is finely divided using a disperser to obtain an inorganic fine particle dispersion having an average particle diameter of 50 to 300 nm. Dispersers suitable for obtaining this dispersion include various types of conventionally known dispersers such as a high-speed rotary disperser, a medium stirring disperser (such as a ball mill and a sand mill), an ultrasonic disperser, a colloid mill disperser, and a high pressure disperser. Can be used. A colloid mill disperser or a high pressure disperser is preferable from the viewpoint of efficiently dispersing the formed fine particles.
[0026]
As a solvent used for the preparation of the inorganic fine particle dispersion and the coating material for the colorant receiving layer, water, an organic solvent, or a mixed solvent thereof can be used. Examples of the organic solvent include alcohols such as methanol, ethanol, n-propanol, i-propanol and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate and toluene. The same solvent can be used also as a solvent in the following other steps.
[0027]
As will be described later, since a compound called a mordant can be suitably used as a dispersant in the present invention, it is not always necessary to add a separate mordant, but by adding a separate mordant, the mordant is received. An embodiment in which the thickness of the mordant-existing portion from the surface of the layer is 10 to 60% with respect to the thickness of the receiving layer is also suitable. In this case, for example, (1) a method of forming a coating layer containing inorganic fine particles, a cationic polymer (dispersing agent), a water-soluble resin and the like, and applying a mordant-containing solution thereon, (2) inorganic fine particles, cationic The coating liquid containing a polymer (dispersant), a water-soluble resin, and the like and a mordant-containing solution can be formed by any method such as a multilayer coating method. The mordant-containing solution may contain inorganic fine particles, a water-soluble resin, a crosslinking agent, and the like.
[0028]
As described above, since a large amount of mordant is present in the surface layer portion of the color material receiving layer, the color material of the ink jet is sufficiently mordanted, and the color density, aging blur, gloss of the printed portion, and the water resistance of characters and images after printing. , Ozone resistance can be improved. Part of the mordant may be contained in the layer initially provided on the support, and in that case, the mordant to be applied later may be the same or different.
[0029]
In the present invention, the colorant-receiving layer coating liquid (coating liquid A) containing at least gas phase method silica that is inorganic fine particles, dispersants A and B, and polyvinyl alcohol that is a water-soluble resin is, for example, It can be prepared as follows. That is,
Vapor phase method silica (fine particles) and dispersants (weight average molecular weight 2000 to 15000) A and B (weight average molecular weight 20000 to 50000) are added to water (for example, silica fine particles in water are 10 to 20% by mass). Using a high-speed rotating wet colloid mill (for example, “CLEARMIX” manufactured by M Technique Co., Ltd.), for example, under a high-speed rotation condition of 10,000 rpm (preferably 5000 to 20000 rpm), for example 20 minutes (preferably 10 to 30) For a vapor phase silica dispersion, and then an aqueous polyvinyl alcohol (PVA) solution (for example, PVA having a mass of about 1/3 of the vapor phase silica) is added thereto, It can be prepared by dispersing under the same rotation conditions as above. In order to impart stability to the coating solution, it is preferable to adjust the pH to about 9.2 with ammonia water or the like. The obtained coating solution can be stably held in a uniform sol state, and is applied to the support by the following coating method and dried to obtain a porous color having a uniform three-dimensional network structure. A material receiving layer can be formed.
[0030]
The colorant-receiving layer coating solution is applied by a known coating method using, for example, an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a bar coater, or the like. be able to.
[0031]
When a basic solution (coating solution B) is applied to the coating layer at the same time as or after coating of the colorant-receiving layer coating solution (coating solution A), the coating solution B is applied after coating. May be added before it shows reduced rate drying. That is, it is preferably manufactured by introducing the coating liquid B after the coating material for the colorant receiving layer (coating liquid A) is applied, while the coating layer exhibits constant rate drying. The coating liquid B can contain a mordant.
[0032]
Here, “before the coating layer comes to show reduced-rate drying” usually refers to a process for several minutes immediately after the application of the coating solution for the colorant-receiving layer. This shows a phenomenon of “constant rate drying” in which the content of the solvent (dispersion medium) in the medium decreases in proportion to time. About the time which shows this "constant rate drying", it describes in chemical engineering handbook (pages 707-712, Maruzen Co., Ltd. issue, October 25, 1980), for example.
[0033]
As described above, after the coating solution A is applied, the coating layer is dried until the coating layer exhibits a reduced rate of drying. This drying is generally performed at 40 to 180 ° C. for 0.5 to 10 minutes (preferably, 0 .5-5 minutes). The drying time naturally varies depending on the coating amount, but the above range is usually appropriate.
[0034]
As a method of applying the coating layer before it shows reduced drying, (1) a method of further coating the coating solution B on the coating layer, (2) a method of spraying by a spraying method, (3) (2) A method of immersing the support on which the coating layer is formed in the coating solution B, etc.
[0035]
In the method (1), examples of the coating method for coating the coating liquid B include, for example, curtain flow coater, extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse roll coater, bar A known coating method using a coater or the like can be used. In particular, it is preferable to use a method in which the coater does not directly contact the coating layer that has already been formed, such as an extrusion die coater, a curtain flow coater, a bar coater, or the like.
[0036]
After application of coating liquid B, it is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes, and dried and cured. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.
[0037]
When the basic solution (coating liquid B) is applied at the same time as the colorant-receiving layer coating liquid (coating liquid A) is applied, the coating liquid A and the coating liquid B come into contact with the support. Thus, a colorant receiving layer can be formed by simultaneous application (multilayer application) on the support, followed by drying and curing.
[0038]
The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, an extrusion die coater or a curtain flow coater. After the simultaneous coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at 40 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 100. It is carried out by heating at a temperature of 0.5 to 5 minutes.
[0039]
When the simultaneous coating (multilayer coating) is performed by, for example, an extrusion die coater, the two types of coating liquid discharged at the same time are close to the discharge port of the extrusion die coater, that is, before moving onto the support. A multilayer is formed, and in that state, the multilayer is applied on the support. Since the two-layer coating liquid layered before coating is likely to cause a cross-linking reaction at the interface between the two liquids when transferred to the support, the two liquids to be ejected are mixed in the vicinity of the discharge port of the extrusion die coater. As a result, thickening is likely to occur, which may hinder the application operation. Therefore, when applying simultaneously as mentioned above, it is preferable to apply the coating solution A and the coating solution B together with the barrier layer solution (intermediate layer solution) between the two solutions and apply the triple layer simultaneously.
[0040]
The barrier layer solution can be selected without particular limitation. For example, an aqueous solution containing a trace amount of water-soluble resin, water, and the like can be given. The water-soluble resin here is used in consideration of coating properties for the purpose of a thickener and the like. For example, cellulose resin (for example, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethyl) is used. Cellulose, etc.), polyvinylpyrrolidone, gelatin and other polymers. The barrier layer liquid may contain the mordant.
[0041]
After the colorant receiving layer is formed on the support, the colorant receiving layer is made of, for example, a super calender, a gloss calendar, etc., and subjected to a calendering process between the roll nips under heat and pressure, so that surface smoothness, gloss It is possible to improve the degree, transparency and coating strength. However, the calendering process may cause a decrease in the porosity (that is, the ink absorbability may be decreased), so it is necessary to set the conditions under which the decrease in the porosity is small.
[0042]
As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable.
Moreover, as a linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.
[0043]
The layer thickness of the colorant receiving layer needs to be determined in relation to the void ratio in the layer because it needs to have an absorption capacity sufficient to absorb all droplets in the case of inkjet recording. For example, the ink amount is 8 nL / mm²In the case where the porosity is 60%, a film having a layer thickness of about 15 μm or more is required.
Considering this point, in the case of inkjet recording, the thickness of the colorant receiving layer is preferably 10 to 50 μm.
[0044]
The pore diameter of the colorant receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and pore median diameter can be measured using a mercury porosimeter (trade name “Bore Sizer 9320-PC2” manufactured by Shimadzu Corporation).
[0045]
The color material receiving layer is preferably excellent in transparency, but as a guide, the haze value when the color material receiving layer is formed on a transparent film support is 30% or less. Preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: manufactured by Suga Test Instruments Co., Ltd.).
[0046]
A polymer fine particle dispersion may be added to a constituent layer (for example, a colorant receiving layer or a back layer) of the ink jet recording sheet of the present invention. This polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-1316648, and 62-110066. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.
[0047]
Next, each component contained in the inorganic fine particle dispersion and the colorant-receiving layer coating solution containing the same will be described in detail.
[0048]
-Dispersant-
In the present invention, as a dispersant, at least two kinds of cationic polymers having different weight average molecular weights are contained in the process of dispersing inorganic fine particles described later. That is, when preparing a coating material for a colorant receiving layer using an inorganic fine particle dispersion in which inorganic fine particles are dispersed, at least two kinds of cationic polymers having different weight average molecular weights are prepared in the preparation step of the inorganic fine particle dispersion. By using in combination, the liquid stability of not only the inorganic fine particle dispersion but also the colorant-receiving layer coating liquid containing the dispersion can be improved.
[0049]
The dispersant (cationic polymer) according to the present invention is dissolved in advance in a solvent such as water as a dispersion medium before the dispersion of the inorganic fine particles, or added after the primary dispersion of the inorganic fine particles and further added to the secondary. When the inorganic fine particles are dispersed, such as by dispersing, they are added to accelerate and stabilize the pulverization or aggregation release. At the time of dispersion, a binder component and its hardener (crosslinking agent) may be contained at the same time.
[0050]
Examples of the cationic polymer include an organic mordant such as a cationic mordant, an inorganic mordant such as a water-soluble metal compound (hereinafter, also simply referred to as “mordant”), and a water-soluble resin component (water-soluble). Resin), and at least two kinds having different weight average molecular weights can be appropriately selected from these and mixed.
[0051]
When the organic mordant or the inorganic mordant is mixed, the dispersibility of the inorganic fine particles and the dispersion stability with time can be improved, and it can interact with a liquid ink having an anionic dye as a coloring material. Thus, the coloring material can be stabilized, and the water resistance and aging resistance after image formation can be improved.
[0052]
As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic functional group is preferably used, but a cationic non-polymer mordant is also used. be able to.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (a mordant monomer), and the mordant monomer and other monomers ( Those obtained as copolymers or condensation polymers with non-mordant monomers) are preferred. Moreover, these polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.
[0053]
Examples of the mordant monomer include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N-dimethyl- N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-Np-vinylbenzyl Ammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N Benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinyl Benzylammonium chloride;
[0054]
Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate;
[0055]
N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternized products of ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted with their anions.
[0056]
Specific examples of the compound include monomethyl diallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, Triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl- 2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylua) C) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) Propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride;
[0057]
N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate.
In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.
[0058]
In addition, allylamine, diallylamine, derivatives thereof, salts and the like can be used. Examples of such compounds include allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, the salts include , Hydrochloride, acetate, sulfate, etc.), diallylethylamine and this salt (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride as counter anion of the salt, Acetate ion sulfate ion etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the amine form, it is a general production method to polymerize in the form of a salt and desalting as required.
In addition, a polymerization unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can be used.
[0059]
The non-mordant monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not interact with a dye in an inkjet ink. Or a monomer having a substantially small interaction.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.
[0060]
The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, specifically, for example, methyl (meth) acrylate or ethyl (meth) acrylate. Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, (meth) Examples include octyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable. The non-mordant monomer can also be used alone or in combination of two or more.
[0061]
Further, as the polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine and derivatives thereof, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl 2-Hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, dicyandiamide-formalin polycondensate dicyan-based chaotic resin, dicyanamide-diethylenetriamine polycondensate-typified polyamine-based chaotic resin, epichlorohydrin-dimethylamine addition Polymer, dimethyldialin ammonium chloride-SO₂Copolymer, diallylamine salt-SO₂Copolymers and the like can also be mentioned as preferable ones.
[0062]
Specific examples of the polymer mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, and 60. -23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122294 No. 60-235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,273,853, JP 4282305, JP 4450224, JP-A-1-16123. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, JP-A-2001-138621, 2000-43401, 2000-212235 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-2093, Examples described in JP-A-8-174992, JP-A-11-192777, JP-A-2001-301314, and the like. Of these, polyallylamine and derivatives thereof are particularly preferable.
[0063]
As the organic mordant in the present invention, polyallylamine having a mass average molecular weight of 100,000 or less and a derivative thereof are particularly preferable from the viewpoint of preventing aging blur.
[0064]
<Polyallylamine and its derivatives>
As polyallylamine and derivatives thereof, various known allylamine polymers and derivatives thereof can be used. Examples of such derivatives include salts of polyallylamine and acids (acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, methanesulfonic acid, toluenesulfonic acid, acetic acid, propionic acid, cinnamic acid, (meth) Organic acids such as acrylic acid, or a combination thereof, or a derivative of allylamine as a salt, or a derivative of polyallylamine by a polymer reaction (for example, repeating structural units represented by the following formulas (1) to (5)) ), Polyallylamine and other copolymerizable monomers (specific examples of such monomers include (meth) acrylic acid esters, styrenes, (meth) acrylamides, acrylonitrile, vinyl). Esters) and the like.
[0065]
[Chemical 1]

[0066]
In the above formula, R⁸¹~ R⁸⁴Represents an organic group which may have a substituent, R⁸⁵And R⁸⁶Are each independently an organic group (R⁸¹~ R⁸⁴Or a hydrogen atom. R⁸⁷Represents a hydrogen atom or a methyl group, R⁸⁸Is -COOR⁸⁹, -CN, -CONR⁹⁰R⁹¹Represents. Where R⁸⁹~ R⁹¹Each independently represents a hydrogen atom, an aliphatic group or an aromatic group. G^-Represents a counter anion.
[0067]
The organic group is a group containing a hydrocarbon moiety and / or a hydrogen halide moiety, and in addition, atoms such as hydrogen, carbon, nitrogen, oxygen, sulfur, phosphorus, silicon, boron, and halogen, and / or The functional group which consists of these combination may be included. Examples of such include (substituted) alkyl groups, (substituted) aralkyl groups, (substituted) aryl groups, (substituted) acyl groups, (substituted) sulfonyl groups, and heterocyclic rings.
[0068]
R⁸¹~ R⁸⁴Specific examples of the organic group represented by formula (1) include alkyl groups (for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl, n-decyl, n-dodecyl, octadecyl, 1,3-butadienyl, 1,3-pentadienyl, etc .; aralkyl group (for example, benzyl, phenylethyl, vinylbenzyl, 1-phenylvinyl, 2 -Phenyl vinyl etc.); aryl groups (for example, phenyl, naphthyl, tolyl, vinyl phenyl etc.) are mentioned.
[0069]
Furthermore, as the organic group having a substituent, fluoroethyl group, trifluoroethyl group, methoxyethyl group, phenoxyethyl group, hydroxyphenylmethyl group, chlorophenyl group, dichlorophenyl group, trichlorophenyl group, bromophenyl group, iodophenyl group, Examples include a fluorophenyl group, a hydroxyphenyl group, a methoxyphenyl group, a hydroxyphenyl group, an acetoxyphenyl group, a cyanophenyl group, and the like.
[0070]
Moreover, the group shown below etc. are mentioned as what has a hydroxyl group.
[Chemical 2]

[0071]
Moreover, the organic group etc. which are shown below are mentioned.
-CR¹⁰¹R¹⁰²-COOR¹⁰³
R¹⁰¹~ R¹⁰³Each independently represents a hydrogen atom, an aliphatic group, or an aromatic group, and examples thereof include a methyl group, an ethyl group, a butyl group, a benzyl group, and a phenyl group.
[0072]
-CO-R¹⁰⁴-COOH
R¹⁰⁴Represents a divalent linking group, for example, —CH₂CH₂-, -CH₂CH₂CH₂-, -CH = CH-, the following linking groups and the like can be mentioned.
[0073]
[Chemical 3]

[0074]
-COR¹⁰⁵, -COOR¹⁰⁶, -CONHR¹⁰⁷, -CSNHR¹⁰⁸, -SO₂R¹⁰⁹, -P (= O) (OR¹¹⁰)₂
R¹⁰⁵~ R¹¹⁰Each independently represents a hydrogen atom, an aliphatic group, or an aromatic group, for example, methyl group, ethyl group, propyl group, butyl group, octadecyl group, benzyl group, phenyl group, -CH = CH-Ph, etc. Is mentioned.
[0075]
R⁸⁷Represents a hydrogen atom or a methyl group. R⁸⁸Is -COOR¹¹¹, -CN, -CONR¹¹²R¹¹³And R¹¹¹~ R¹¹³Each independently represents a hydrogen atom, an aliphatic group, or an aromatic group.
R¹¹¹~ R¹¹³Specific examples of the hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, Cyclohexyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, octadecyl group, allyl group, benzyl group, phenyl group, naphthyl group, biphenyl group, 1,1,1-trifluoroethyl Group, 2-hydroxy-3-chloropropyl group and the like.
[0076]
G^-As a specific example, a halogen ion (Cl^-, Br^-, I^-), Sulfonate ions, alkyl sulfonate ions, aryl sulfonate ions, alkyl carboxylic acid ions, aryl carboxylic acid ions, and the like.
[0077]
The structure of these polyallylamine derivatives is not particularly limited, but the obtained polymer is preferably soluble in an organic solvent that is water-soluble or miscible with water, but also in the form of water-dispersible latex particles. Can be used.
[0078]
Specific examples of polyallylamine and derivatives thereof include polydimethyldiallylammonium chloride, polymonomethyldiallylammonium chloride, and JP-B-62-31722, JP-B-2-14364, JP-B-63-43402, and 63-43403. No. 63-45721 No. 63-29881 No. 1-26362 No. 2-56365 No. 2-57084 No. 4-41686 No. 6-2780 No. 6-45649 No. 6-45649 JP-A-6-15592, JP-A-4-68622, JP-A-3199227, JP-A-3008369, JP-A-10-330427, JP-A-11-21321, JP-A-2000-281728, JP-A-2001-106737. Sho 62-256801, JP-A-7-173286, 7-213897, 9- No. 35318, No. 9-302026, No. 11-21321, WO99 / 21901, WO99 / 19372, JP-A-5-140213, JP-A-11-506488, and the like. .
[0079]
Examples of the inorganic mordant include polyvalent water-soluble metal salts and hydrophobic metal salt compounds. For example, magnesium, alumina, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium, samarium, Examples include salts or complexes of metals selected from europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, bismuth.
[0080]
Specific examples include calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, secondary chloride Copper, ammonium chloride (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate Hexahydrate, nickel amidosulfate tetrahydrate, alumina sulfate, alumina alum, basic polyaluminum hydroxide, sulfite alumina, thiosulfate alumina, polychlorinated alumina, alumina nitrate nonahydrate, alumina chloride hexahydrate , Ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, phenol Zinc sulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, zirconium acetylacetonate, zirconyl acetate, zirconyl sulfate, zirconium carbonate Ammonium, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride,
[0081]
Hydroxy zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungsto Acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid hydrate, potassium nitrate, manganese acetate, germanium nitrate, strontium nitrate, yttrium acetate, yttrium chloride, yttrium nitrate, indium nitrate, lanthanum nitrate, lanthanum chloride lanthanum acetate, benzoic acid Lanthanum, cerium chloride, cerium sulfate, cerium octylate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, dysprosium nitrate, erbium nitrate, glass Ytterbium, hafnium chloride, and bismuth nitrate.
[0082]
Among the inorganic mordants, alumina-containing compounds, titanium-containing compounds, zirconium-containing compounds, and group IIIB series metal compounds (salts or complexes) of the periodic table are preferable.
[0083]
Further, the water-soluble resin can be mixed as a dispersant without mixing the mordant or together with the mordant. Even when a water-soluble resin is mixed, the dispersibility of the inorganic fine particles and the dispersion stability over time can be improved.
[0084]
Examples of the water-soluble resin include polyvinyl alcohol (PVA), which is a resin having a hydroxy group as a hydrophilic structural unit, acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and polyvinyl acetal. , Cellulose resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), etc.], chitins, chitosans, starch; resins having ether bonds Certain polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE); Polyacrylamide resins having a bromide group or an amide bond (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, and the like.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.
[0085]
Among these, polyvinyl alcohol or a derivative thereof is particularly preferable. Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-18801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, etc. Kill.
[0086]
When the water-soluble resin is mixed as a dispersant into the inorganic fine particle dispersion, it can be used within the range of the amount of the dispersant described above. In addition to the water-soluble resin used as the dispersant, it can be further added during the preparation of the colorant-receiving layer coating solution.
Therefore, the total amount of the water-soluble resin is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid mass of the layer when the colorant receiving layer is formed.
The inorganic fine particles and the water-soluble resin described later, which mainly constitute the color material receiving layer according to the present invention, may each be a single material or a mixed system of a plurality of materials. .
[0087]
From the viewpoint of maintaining transparency, the type of water-soluble resin combined with the fine particles, particularly silica fine particles, is important. When the vapor phase silica is used, the water-soluble resin is preferably polyvinyl alcohol (PVA), more preferably PVA having a saponification degree of 70 to 100%, and a saponification degree of 80 to 99.5%. PVA is particularly preferred.
[0088]
The polyvinyl alcohol (PVA) has a hydroxyl group in its structural unit. Since this hydroxyl group and the surface silanol group of the silica fine particle form a hydrogen bond, the secondary particle of the silica fine particle is a three-dimensional network unit. It becomes easy to form a network structure. By forming this three-dimensional network structure, it is considered that a color material receiving layer having a porous structure having a high porosity and sufficient strength is formed.
In ink-jet recording, the porous colorant-receiving layer obtained as described above can absorb ink rapidly by capillary action and form dots with good roundness without ink smearing.
[0089]
Polyvinyl acetal, cellulose resin [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), etc.], chitins, chitosans, starch; ether bond Polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) that are resins having polyamide (PAAM), polyvinyl pyrrolidone (PVP) that is a resin having an amide group or an amide bond , Polyacrylic acid hydrazide, and other water-soluble resins such as polyacrylates, maleic acid resins, alginates, gelatins having carboxy groups as dissociative groups It may be use. When the other water-soluble resin and the polyvinyl alcohol are used in combination, the content of polyvinyl alcohol in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.
[0090]
Among the above cationic polymers, it is preferable to use a cationic mordant as a dispersant, and it is particularly preferable to use polydimethyldiallylammonium chloride and polymonomethyldiallylammonium chloride as a dispersant. These two types are mixed and mixed. Is most preferred.
[0091]
The above water-soluble resin is used as a dispersant for inorganic fine particles, and is added to the inorganic fine particle dispersion prepared in advance during the preparation of the coating material for the colorant receiving layer, or an aqueous solution containing a separate water-soluble resin is prepared. In addition, it can be contained in the colorant receiving layer as a binder component, for example, by mixing it with an inorganic fine particle dispersion. The water-soluble resin can be formed into a colorant-receiving layer that is strong and excellent in durability by being crosslinked by a crosslinking agent described later.
[0092]
The mass content ratio [PB ratio (x / y)] between the inorganic fine particles (x) and the water-soluble resin (y) in the color material receiving layer formed by coating is determined by the film structure and film strength of the color material receiving layer. It has a big impact. That is, as the mass content ratio [PB ratio] increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.
As the mass content ratio [PB ratio (x / y)] in the present invention, it is possible to prevent a decrease in film strength and cracking during drying due to an excessively large PB ratio, and a PB ratio is too small. From the viewpoint of preventing the ink absorbability from being lowered due to the void being easily blocked by the resin and decreasing the void ratio, 1.5: 1 to 10: 1 is preferable.
[0093]
Since stress may be applied to the recording sheet when passing through the conveyance system of the ink jet printer, the color material receiving layer needs to have sufficient film strength. In the case of cutting into a sheet shape, it is necessary that the color material receiving layer has sufficient film strength in order to prevent the color material receiving layer from being cracked or peeled off. In consideration of these cases, the mass ratio (x / y) is more preferably 5: 1 or less, while it is more preferably 2: 1 or more from the viewpoint of ensuring high-speed ink absorbency in an inkjet printer. preferable.
[0094]
For example, a coating solution in which gas phase method silica fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a mass ratio (x / y) of 2: 1 to 5: 1 is provided on the support. When the coating layer is dried, a three-dimensional network structure in which secondary particles of silica fine particles are network chains is formed, the average pore diameter is 30 nm or less, the porosity is 50 to 80%, the pore ratio Volume is 0.5ml / g or more, specific surface area is 100m²A translucent porous film of at least / g can be easily formed.
[0095]
-Inorganic fine particles-
The colorant receiving layer of the ink jet recording sheet has a porous structure by containing inorganic fine particles, thereby improving the ink absorption performance. In particular, if the solid content of the inorganic fine particles in the colorant-receiving layer is 60% by mass or more, more preferably more than 65% by mass, it is possible to form a more favorable porous structure, and sufficient ink This is preferable because an ink jet recording sheet having absorbency can be obtained. Here, the solid content in the coloring material receiving layer of the inorganic fine particles is a content calculated based on components other than water in the composition constituting the coloring material receiving layer.
[0096]
Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide, and hydroxide. Zinc, alumina, alumina silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, yttrium oxide and the like can be mentioned. Among these, silica fine particles, colloidal silica, pseudo boehmite, and alumina fine particles are preferable from the viewpoint of forming a good porous structure.
[0097]
The inorganic fine particles may be used as primary particles or in a state where secondary particles are formed. The average primary particle size of these inorganic fine particles is preferably 2 μm or less, and more preferably 200 nm or less. In particular, silica fine particles having an average primary particle size of 20 nm or less, alumina fine particles having an average primary particle size of 20 nm or less, or pseudoboehmite having an average pore radius of 2 to 15 nm is more preferable.
[0098]
Silica fine particles are generally roughly classified into wet method particles and dry method (gas phase method) particles according to the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and “gas phase method silica” means anhydrous silica fine particles obtained by the gas phase method. As the silica fine particles used in the present invention, gas phase method silica fine particles are particularly preferable.
[0099]
Vapor phase silica is different from hydrous silica in terms of the density of silanol groups on the surface, the presence or absence of vacancies, etc., and exhibits different properties, but is suitable for forming a three-dimensional structure with a high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is 5 to 8 / nm.²In the case of vapor phase silica, the density of silanol groups on the fine particle surface is 2 to 3 / nm.²Therefore, it is presumed that the structure becomes sparsely soft agglomerated (flocculated), and as a result, has a structure with a high porosity.
[0100]
Vapor phase silica has a particularly large specific surface area, so ink absorption and retention efficiency is high, and since the refractive index is low, transparency can be imparted to the receiving layer by dispersing to an appropriate particle size. It is characterized by high color density and good color development. The transparency of the receiving layer is not only for applications that require transparency such as OHP, but also in terms of obtaining high color density and good color development gloss even when applied to recording sheets such as photo glossy paper. is important.
[0101]
The average primary particle diameter of the vapor phase silica is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Since the vapor phase silica is easily adhered to each other by hydrogen bonding with a silanol group, a structure having a large porosity can be formed when the average primary particle diameter is 30 nm or less, and ink absorption characteristics are effectively improved. Can be improved.
[0102]
Silica fine particles may be used in combination with the other inorganic fine particles described above. When the other inorganic fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in all the inorganic fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.
[0103]
As the inorganic fine particles used in the present invention, alumina fine particles, alumina hydrate, a mixture or a composite thereof are also preferable. Of these, alumina hydrate is preferable because it absorbs and fixes ink well. In particular, pseudoboehmite (Al₂O_Three・ NH₂O) is preferred. Alumina hydrates can be used in various forms, but it is preferable to use sol boehmite as a raw material because a smooth layer can be easily obtained.
[0104]
About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 30 nm, and more preferably 2 to 15 nm. The pore volume is preferably 0.3 to 2.0 cc / g, more preferably 0.5 to 1.5 cc / g. Here, the pore radius and pore volume are measured by a nitrogen adsorption / desorption method, and can be measured by, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter). .
Among alumina fine particles, vapor-phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle size of the vapor phase alumina is preferably 30 nm or less, and more preferably 20 nm or less.
[0105]
When the above-mentioned inorganic fine particles are used in an inkjet recording sheet, for example, JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, and JP-A-2001-2001. 138621, 2000-43401, 2000-21235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8- The embodiments disclosed in Japanese Patent Nos. 2090, 8-2091, 8-2093, 8-174992, 11-192777, and JP-A-2001-301314 can also be preferably used.
[0106]
In order to improve the dispersibility of the inorganic fine particles, the surface of the inorganic fine particles may be treated with a silane coupling agent. As the silane coupling agent, an organic functional group (for example, a vinyl group, an amino group, an epoxy group, a mercapto group, a chloro group, an alkyl group, a phenyl group, an ester group, etc.) in addition to the site where the coupling treatment is performed. What has is preferable.
[0107]
-Crosslinking agent-
The colorant-receiving layer of the ink jet recording sheet of the present invention includes a coating layer containing fine particles and a water-soluble resin, and further includes a crosslinking agent capable of crosslinking the water-soluble resin, and a crosslinking reaction between the crosslinking agent and the water-soluble resin. The aspect which is the porous layer hardened | cured by is preferable.
[0108]
Boron compounds are preferred for crosslinking the above water-soluble resins, particularly polyvinyl alcohol resins. Examples of the boron compound include borax, boric acid, and borate (for example, orthoborate, InBO)._Three, ScBO_Three, YBO_Three, LaBO_Three, Mg_Three(BO_Three)₂, Co_Three(BO_Three)₂Diborate (eg Mg₂B₂O_Five, Co₂B₂O_Five), Metaborates (eg LiBO)₂, Ca (BO₂)₂, NaBO₂, KBO₂), Tetraborate (eg, Na₂B_FourO₇・ 10H₂O), pentaborate (for example, KB)_FiveO₈・ 4H₂O, Ca₂B₆O₁₁・ 7H₂O, CsB_FiveO_FiveAnd the like. Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.
[0109]
The following compounds other than the boron compound can also be used as the crosslinking agent for the water-soluble resin.
For example, aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin; melamine resins (for example, methylolmelamine, alkylated methylolmelamine) ;Epoxy resin;
[0110]
Isocyanate compounds such as 1,6-hexamethylene diisocyanate; aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; carboximide compounds described in US Pat. No. 3,100,704; glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane compounds such as dioxane; Titanium lactate, aluminum sulfate, chromium alum, potassium alum, metal-containing compounds such as zirconyl acetate and chromium acetate, polyamine compounds such as tetraethylenepentamine, hydrazide compounds such as adipic acid dihydrazide It is a small molecule or polymer or the like containing an oxazoline group two or more.
The above crosslinking agents may be used singly or in combination of two or more.
[0111]
Crosslinking curing is performed by adding a crosslinking agent to a coating solution (coating solution A) and / or the following basic solution containing inorganic fine particles, a cationic polymer, a water-soluble resin, and (1) applying the coating solution A. When the coating layer is formed at the same time, or (2) at any time during the drying of the coating layer formed by coating the coating liquid A and before the coating layer exhibits reduced-rate drying, pH 8 It is preferable to carry out by applying the above basic solution (coating solution B) to the coating layer.
[0112]
The application of the cross-linking agent is preferably performed as described below when a boron compound is taken as an example. That is, when the color material receiving layer is a layer obtained by cross-linking and curing the coating layer coated with the color material receiving layer coating liquid (coating liquid A) containing inorganic fine particles and a dispersant, the cross-linking curing is (1 ) At the same time when the coating solution A is applied to form a coating layer, (2) the coating layer formed by coating the coating solution A is being dried and before the coating layer exhibits reduced-rate drying. At any time, it is carried out by applying a basic solution (coating solution B) having a pH of 8 or higher to the coating layer. The boron compound as the crosslinking agent may be contained in either the coating liquid A or the coating liquid B, and may be contained in both the coating liquid A and the coating liquid B.
1-50 mass% is preferable with respect to the water-soluble resin in a layer, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.
[0113]
-Other ingredients-
The ink jet recording sheet of the present invention may further contain various known additives, for example, an ultraviolet absorber, an antioxidant, a fluorescent brightening agent, a monomer, a polymerization initiator, a polymerization inhibitor, a blurring inhibitor, if necessary. An antiseptic, a viscosity stabilizer, an antifoaming agent, a surfactant, an antistatic agent, a matting agent, an anti-curling agent, a water-proofing agent and the like can be contained.
The cationic polymer (mordant) is preferably used in combination with a fastness improver such as an ultraviolet absorber, an antioxidant, or a bleeding inhibitor.
[0114]
These UV absorbers, antioxidants, and blurring inhibitors that may be used in combination include alkylated phenolic compounds (including hindered phenolic compounds), alkylthiomethylphenolic compounds, hydroquinone compounds, alkylated hydroquinone compounds, tocopherols. Compounds, thiodiphenyl ether compounds, compounds having two or more thioether bonds, bisphenolic compounds, O-, N- and S-benzyl compounds, hydroxybenzyl compounds, triazine compounds, phosphonate compounds, acylaminophenolic compounds, ester compounds, Amide compound, ascorbic acid, amine-based antioxidant, 2- (2-hydroxyphenyl) benzotriazole compound, 2-hydroxybenzophenone compound, acrylate, water-soluble or hydrophobic metal salt, Mechanical metal compounds, metal complexes, hindered amine compounds (including TEMPO compounds), 2- (2-hydroxyphenyl) 1,3,5, -triazine compounds, metal deactivators, phosphite compounds, phosphonite compounds, hydroxyamine compounds , Nitrone compound, peroxide scavenger, polyamide stabilizer, polyether compound, basic auxiliary stabilizer, nucleating agent, benzofuranone compound, indolinone compound, phosphine compound, polyamine compound, thiourea compound, urea compound, hydrazite compound, amidine compound , Sugar compounds, hydroxybenzoic acid compounds, dihydroxybenzoic acid compounds, trihydroxybenzoic acid compounds, and the like.
[0115]
Among these, alkylated phenolic compounds, compounds having two or more thioether bonds, bisphenolic compounds, ascorbic acid, amine-based antioxidants, water-soluble or hydrophobic metal salts, organometallic compounds, metal complexes, hindered amines It is preferable to use a combination of at least one of compounds, polyamine compounds, thiourea compounds, hydrazide compounds, hydroxybenzoic acid compounds, dihydroxybenzoic acid compounds and trihydroxybenzoic acid compounds.
[0116]
Specific examples of the compound include JP-A-10-182621, JP-A-2001-260519, JP-B-4-34953, JP-B-4-34513, JP-A-11-170686, JP-A-2001-152237, JP 4-34512, EP 1138509, JP 60-67190, JP 7-276808, JP 2001-94829, JP 47-10537, 58-111942, 58-212844. Gazettes, 59-19945 gazettes, 59-46646 gazettes, 59-109055 gazettes, 63-53544 gazettes, 36-36466 gazettes, 42-26187 gazettes, and 48-30492 gazettes. Gazette, 48-31255, 48-41572, 48-54965, 50 10726 JP, U.S. Patent Nos. 2,719,086, 3,707,375, the 3,754,919 Pat, the 4,220,711 Pat;
[0117]
Japanese Patent Publication Nos. 45-4699, 54-5324, European Published Patent No. 223739, No. 309401, No. 309402, No. 310551, No. 310552, No. 459416, German Published Patent No. 3435443, JP-A-54-48535, JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472 Publication No. 60-287485, No. 60-287486, No. 60-287487, No. 60-287488, No. 61-160287, No. 61-185483, No. 61-2111079. 62-146678, 62-146680, 62-146679, 62-282858, 62-262447, 63-05174, 63-89877, 63-88380, 66-88381, 63 No. 113536 publication;
[0118]
JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.
[0119]
Other components may be used alone or in combination of two or more. Other components may be added after being water-solubilized, dispersed, polymer-dispersed, emulsified or formed into oil droplets, or may be encapsulated in microcapsules. As addition amount in the case of adding other components, 0.01 to 10 g / m²Is preferred.
[0120]
In the present invention, the colorant-receiving layer coating liquid preferably contains a surfactant. As the surfactant, any of cationic, anionic, nonionic, amphoteric, fluorine and silicon surfactants can be used.
Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers (for example, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyalkylene ether) Ethylene nonylphenyl ether), oxyethylene / oxypropylene block copolymer, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene) Sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitant Oleate, etc.), polyoxyethylene sorbitol fatty acid esters (eg, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (eg, glycerol monooleate), polyoxyethylene glycerin fatty acid esters (polyoxymonostearate) Ethylene glycerol, monooleic acid polyoxyethylene glycerin, etc.), polyoxyethylene fatty acid esters (polyethylene glycol monolaurate, polyethylene glycol monooleate, etc.), polyoxyethylene alkylamine, acetylene glycols (eg, 2, 4, 7) , 9-tetramethyl-5-decyne-4,7-diol, and ethylene oxide adducts and propylene oxide adducts of the diols), and the like. Sharp emission alkyl ethers are preferable. The nonionic surfactant can be used in the coating liquid A and the coating liquid B. Moreover, the said nonionic surfactant may be used independently and may use 2 or more types together.
[0121]
Examples of the amphoteric surfactant include amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, imidazolium betaine type, and the like, for example, US Pat. No. 3,843,368, Those described in JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, and JP-A-10-282619 can be suitably used. As the amphoteric surfactant, an amino acid type amphoteric surfactant is preferable, and as the amino acid type amphoteric surfactant, as described in JP-A-5-303205, for example, an amino acid (glycine, glutamic acid, Histidine acid etc.) and N-aminoacyl acids and salts thereof into which long chain acyl groups have been introduced. The amphoteric surfactant may be used alone or in combination of two or more.
[0122]
Examples of the anionic surfactant include fatty acid salts (for example, sodium stearate, potassium oleate), alkyl sulfate esters (for example, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (for example, sodium dodecylbenzenesulfonate). Alkyl sulfosuccinate (for example, sodium dioctyl sulfosuccinate), alkyl diphenyl ether disulfonate, alkyl phosphate, and the like.
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, pyridinium salts, imidazolium salts, and the like.
[0123]
Examples of the fluorosurfactant include compounds derived via an intermediate having a perfluoroalkyl group using a method such as electrolytic fluorination, telomerization, or oligomerization. Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trialkyl ammonium salts, perfluoroalkyl group-containing oligomers, and perfluoroalkyl phosphate esters.
[0124]
As the silicon-based surfactant, silicon oil modified with an organic group is preferable, and a structure in which a side chain of a siloxane structure is modified with an organic group, a structure in which both ends are modified, and a structure in which one end is modified can be taken. Examples of the organic group modification include amino modification, polyether modification, epoxy modification, carboxyl modification, carbinol modification, alkyl modification, aralkyl modification, phenol modification, and fluorine modification.
[0125]
In the present invention, the content of the surfactant is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0% with respect to the coating solution for the colorant receiving layer. When two or more liquids are used as the colorant-receiving layer coating liquid, it is preferable to add a surfactant to each coating liquid.
[0126]
In the present invention, the colorant receiving layer preferably contains a high boiling point organic solvent for curling prevention. The high-boiling organic solvent is an organic compound having a boiling point of 150 ° C. or higher at normal pressure, and is a water-soluble or hydrophobic compound. These may be liquid or solid at room temperature, and may be low molecules or polymers.
Specifically, aromatic carboxylic acid esters (for example, dibutyl phthalate, diphenyl phthalate, phenyl benzoate, etc.), aliphatic carboxylic acid esters (for example, dioctyl adipate, dibutyl sebacate, methyl stearate, dibutyl maleate) , Dibutyl fumarate, triethyl acetyl citrate, etc.), phosphate esters (eg, trioctyl phosphate, tricresyl phosphate, etc.), epoxies (eg, epoxidized soybean oil, epoxidized fatty acid methyl, etc.), alcohols (eg, stearyl) Alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerol, diethylene glycol monobutyl ether (DEGMBE), triethylene glycol monobutyl ether, glycerol Methyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, triethanolamine, polyethylene glycol, etc. ), Vegetable oils (eg, soybean oil, sunflower oil, etc.) and higher aliphatic carboxylic acids (eg, linoleic acid, oleic acid, etc.).
[0127]
(Support)
As the support, either a transparent support made of a transparent material such as plastic or an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the colorant receiving layer, it is preferable to use a transparent support or a highly glossy opaque support.
[0128]
The material that can be used for the transparent support is preferably a material that is transparent and can withstand radiant heat when used in an OHP or a backlight display. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point which is easy to handle.
[0129]
As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the colorant receiving layer is provided is preferable. The glossiness is a value determined according to the method described in JIS P-8142 (75-degree specular gloss test method for paper and paperboard). Specifically, the following supports are mentioned.
[0130]
For example, high gloss paper support such as art paper, coated paper, cast coated paper, baryta paper used for silver salt photographic support, etc .; polyesters such as polyethylene terephthalate (PET), nitrocellulose, cellulose acetate , Cellulose esters such as cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, and polyamide are made opaque by adding a white pigment or the like (surface calendering may be applied). Glossy film; or a support in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of a highly glossy film containing the various paper supports, the transparent support or the white pigment. Etc.
A white pigment-containing foamed polyester film (for example, foamed PET containing polyolefin fine particles and forming voids by stretching) can also be suitably exemplified. Furthermore, resin-coated paper used for silver salt photographic printing paper is also suitable.
[0131]
Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of handleability.
[0132]
The surface of the support may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, etc. in order to improve wettability and adhesion.
[0133]
Next, the base paper used for the resin-coated paper will be described in detail.
As the base paper, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp as necessary. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used. preferable.
However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.
[0134]
The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.
[0135]
In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.
[0136]
The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% and a 42 mesh residual as defined in JIS P-8207. 30 to 70% of the sum with the mass% of is preferable. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.
[0137]
The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. Base paper density is 0.7-1.2g / m²(JIS P-8118) is common.
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.
[0138]
A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, a sizing agent similar to the size that can be added to the base paper can be used.
The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method defined in JIS P-8113.
[0139]
The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but some other LLDPE, polypropylene, etc. can also be used.
[0140]
In particular, the polyethylene layer on the side on which the colorant-receiving layer is formed is obtained by adding rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine blue to polyethylene, as is widely done in photographic paper. What improved transparency, whiteness, and hue is preferable. Here, as a titanium oxide content, about 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable. Although the thickness of a polyethylene layer does not have limitation in particular, 10-50 micrometers is suitable for both front and back layers. Further, an undercoat layer can be provided on the polyethylene layer in order to provide adhesion to the colorant receiving layer. As the undercoat layer, aqueous polyester, gelatin and PVA are preferable. Moreover, as thickness of this undercoat layer, 0.01-5 micrometers is preferable.
[0141]
Polyethylene-coated paper can be used as glossy paper, or when it is coated by melt-extruding polyethylene onto the surface of the base paper, a matte or silky surface that can be obtained with ordinary photographic printing paper by performing a so-called molding process. Can also be used.
[0142]
A back coat layer can be provided on the support, and examples of components that can be added to the back coat layer include a white pigment, an aqueous binder, and other components.
Examples of white pigments contained in the backcoat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. , Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white inorganic pigment, styrene And organic pigments such as polyethylene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.
[0143]
Examples of the aqueous binder used in the back coat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxy Examples thereof include water-soluble polymers such as methyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.
Examples of other components contained in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.
[0144]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%” unless otherwise specified, and “molecular weight” represents “weight average molecular weight”.
[0145]
(Production of support)
Wood pulp consisting of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All parts were added at an absolutely dry mass ratio to the pulp, and weighed by a long paper machine to 170 g / m.²Paper was made.
[0146]
In order to adjust the surface size of the base paper, 0.04% of a fluorescent whitening agent (“Whiteex BB” manufactured by Sumitomo Chemical Co., Ltd.) is added to a 4% aqueous solution of polyvinyl alcohol, and this is 0 in terms of absolute dry mass. .5g / m²The base paper was impregnated so as to become, dried, and then subjected to a calendar treatment to obtain a base paper adjusted to a density of 1.05 g / cc.
[0147]
After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 19 μm using a melt extruder to form a resin layer composed of a mat surface. (Hereinafter, the resin layer surface is referred to as “back surface”). The resin layer on the back side is further subjected to corona discharge treatment, and thereafter, as an antistatic agent, aluminum oxide (“Alumina sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (“Nissan Chemical Industries, Ltd. Snowtex O ")) in water at a mass ratio of 1: 2 is a dry mass of 0.2 g / m²It applied so that it might become.
[0148]
Furthermore, after the corona discharge treatment was performed on the felt surface (front surface) side on which the resin layer was not provided, 10% anatase-type titanium dioxide, a trace amount of ultramarine blue, and 0.01% fluorescent whitening agent (against polyethylene) ) And MFR (melt flow rate) 3.8 low density polyethylene is extruded to a thickness of 29 μm using a melt extruder to form a high gloss thermoplastic layer on the surface of the base paper (Hereinafter, this high-gloss surface is referred to as the “front side”) and used as a support.
[0149]
[Examples 1 to 3, Comparative Examples 1 to 4]
(Preparation of coating material A for colorant receiving layer)
(1) Vapor phase silica fine particles, (2) ion-exchanged water, and (3) the dispersant shown in Table 1 below are mixed, and a high-speed rotating colloid mill (“Claire” manufactured by M Technique Co., Ltd.) is mixed. Mix)) at a rotational speed of 10,000 rpm for 20 minutes to prepare an inorganic fine particle dispersion, and then into the inorganic fine particle dispersion, the following (4) polyvinyl alcohol, (5) boric acid and (6) A solution containing polyoxyethylene lauryl ether and (7) ion-exchanged water was added, and dispersion was performed again at a rotational speed of 10,000 rpm for 20 minutes to prepare a coating material A for a colorant receiving layer.
The mass ratio of the silica fine particles to the water-soluble resin (PB ratio = (1) :( 4)) is 4.5: 1, and the pH of the coating solution A for the colorant receiving layer is 3.5 and is acidic. Indicated.
[0150]
<Composition of Color Material Receiving Layer Coating Liquid A>
(1) Gas phase method silica fine particles (inorganic fine particles) 10.0 parts
(Leoroseal QS30, average primary particle size 7 nm, manufactured by Tokuyama Corporation)
(2) Ion exchange water: 51.7 parts
(3) The following dispersant (see Table 1 below)
(4) Polyvinyl alcohol (water-soluble resin) 8% aqueous solution 27.8 parts
(PVA124, saponification degree 98.5%, polymerization degree 2400, manufactured by Kuraray Co., Ltd.)
(5) Boric acid (crosslinking agent): 0.4 parts
(6) Polyoxyethylene lauryl ether (surfactant) ... 1.2 parts
(Emulgen 109P (10% aqueous solution), HLB value 13.6, manufactured by Kao Corporation)
(7) Ion exchange water: 33.0 parts
[0151]
[Table 1]

[0152]
(Preparation of inkjet recording sheet)
After the corona discharge treatment is applied to the front surface of the support, the colorant receiving layer coating liquid A obtained above is applied to the front surface of the support at 200 ml / m using an extrusion die coater.²(Application step), and dried with a hot air dryer at 80 ° C. (wind speed 3 to 8 m / second) until the solid content concentration of the coating layer reached 20%. This coating layer showed constant rate drying during this period. Immediately after that, it was soaked in a mordant solution B having the following composition for 30 seconds, and 20 g / m on the coating layer.²Was attached (step of applying a mordant solution) and further dried at 80 ° C. for 10 minutes (drying step). This produced the inkjet recording sheet of the present invention provided with a colorant receiving layer having a dry film thickness of 32 μm.
[0153]
<Composition of mordant solution B>
(1) Boric acid (crosslinking agent) 0.65 parts
(2) 10% aqueous solution of polyallylamine “PAA-10C”: 25 parts
(Mordant, manufactured by Nittobo Co., Ltd.)
(3) Ion exchange water: 59.7 parts
(4) Ammonium chloride (surface pH adjuster): 0.8 parts
(5) Polyoxyethylene lauryl ether (surfactant) 10 parts
(Emulgen 109P, 2% aqueous solution, HLB value 13.6, manufactured by Kao Corporation)
(6) 10% aqueous solution of MegaFuck “F1405” 2.0 parts
(Fluorosurfactant, manufactured by Dainippon Ink & Chemicals, Inc.)
[0154]
(Evaluation)
(1) Solution stability of coating solution A for colorant receiving layer
For each colorant receiving layer coating solution A prepared in each of the examples and comparative examples, the viscosity at a liquid temperature of 30 ° C. was measured immediately after the preparation and after storage for 7 days in a 30 ° C. environment. It was measured by a meter. The measurement results are shown in Table 2 below.
[0155]
(2) aging
About each inkjet recording sheet produced using the coating liquid A for the colorant receiving layer obtained in each Example and Comparative Example, using an inkjet printer (“PM-900C” manufactured by Seiko Epson Corporation), magenta A grid-like linear pattern (line width 0.28 mm) in which the ink and the black ink are adjacent to each other is printed, and the visual density D is measured by “X-rite 310TR” manufactured by X-rite.¹Was measured. Subsequently, after being left for 3 hours after printing, it was stored in a constant temperature and humidity chamber at a temperature of 40 ° C. and a relative humidity of 90% for 1 day, and then again the visual density D as described above.²And the concentration difference ΔOD (= D¹-D²) Was evaluated for aging blur. The smaller the value of the concentration difference (ΔOD), the more the occurrence of aging blur is suppressed. The evaluation results are shown in Table 2 below.
[0156]
[Table 2]

[0157]
From the results of Table 2 above, in preparing a coating material for a colorant receiving layer, Examples were obtained by dispersing inorganic fine particles using two kinds of cationic polymers (dispersing agents) having different weight average molecular weights to obtain inorganic fine particle dispersions. 1 to 3, it was shown that the prepared coating material for the colorant receiving layer can be stably held without greatly thickening with time, and the liquid stability is good. In addition, all of the inkjet recording sheets prepared using these colorant-receiving layer coating liquids had good ink-receiving properties such as ink absorbency, and at the same time, aging of images was suppressed.
On the other hand, in the comparative examples in which only one type of dispersant was mixed in the dispersion of the inorganic fine particles, the viscosity was high and the dispersibility was not always sufficient, and the viscosity increased with time and the dispersibility decreased. In addition, the ink jet recording sheet obtained by using these is particularly inferior in terms of aging blur. Thus, in the comparative example, the dispersion stability of the inorganic fine particles was improved, and at the same time, it was not possible to improve the aging blur.
[0158]
【The invention's effect】
According to the present invention, in preparing a coating liquid for forming a colorant-receiving layer, the stability of an inorganic fine particle dispersion in which inorganic fine particles are dispersed is improved, and the yield is suppressed and the productivity of an inkjet recording sheet is improved. The manufacturing method of the sheet | seat for inkjet recording which can be provided can be provided. Also,
According to the present invention, there is provided an ink jet recording sheet which is obtained by the above-described method for producing an ink jet recording sheet of the present invention, has good ink absorbency, has no blurring with time, and has excellent productivity. be able to.

Claims (5)

In the method for producing an ink jet recording sheet, a color material receiving layer coating liquid comprising an inorganic fine particle dispersion in which inorganic fine particles are dispersed is applied onto a support to form a color material receiving layer.
An inorganic fine particle dispersion is prepared by mixing and dispersing the inorganic fine particles with at least two kinds of cationic polymers including a cationic polymer having a weight average molecular weight of 2,000 to 15000 and a cationic polymer having a weight average molecular weight of 20,000 to 50,000. A method for producing an ink jet recording sheet, further comprising adding a water-soluble resin and a crosslinking agent for crosslinking the water-soluble resin to the prepared inorganic fine particle dispersion. The method for producing an ink jet recording sheet according to claim 1 , wherein at least two of the cationic polymers are polydimethyldiallylammonium chloride and polymonomethyldiallylammonium chloride. The method for producing a sheet for inkjet recording according to claim 1 or 2 , wherein the mixing amount of each kind of the cationic polymer is 10% by mass or more based on the total mass of all the cationic polymers to be mixed. The total mixing amount of the least two cationic polymers, the manufacture of ink jet recording sheet according to any one of claims 1 to 3 which is a 3-8 wt% of the mixed mass of the inorganic fine particles Method. Ink jet recording sheet characterized by being obtained by the method for producing an ink jet recording sheet according to any one of claims 1-4.