JP2004082694A - Medium to be recorded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medium to be recorded which exhibits high image density, good color tones and ink absorbency, suppresses fading and discoloration of an image during long-term preservation, concurrently improves migration of dye ink, and further suppresses yellowing on a white ground. <P>SOLUTION: One or more ink receiving layers are provided on at least one of surfaces of a base material. The receiving layer contains, as a binder, a water-soluble resin and/or a water dispersive resin, inorganic particles (A), at least one of compounds (B) expressed by general formulas (1) to (4), an acrylamide-diallylamine hydrochloride copolymer (C) and a boronic compound (D), wherein the ratio in masses of (A), (B), (C) and (D) are expressed by 4 × (B + C + D)≤ A and (B/D):C = 0.1:5 to 15:0.1. <P>COPYRIGHT: (C)2004,JPO

Description

（式中ＸおよびＹは同一若しくは異なっていてもよく、それぞれ独立にＣＯＯＨ基或いはＯＨ基を表す。また、Ｒ^１およびＲ^２は同一若しくは異なっていてもよく、アルキレン基またはアリーレン基を表わす。ｎは１または２の整数を表す。）
【００１５】

（式中、Ｒ^１〜Ｒ^４は、同一若しくは異なっていてもよく、水素原子、アルキル基またはアリール基を表わす。また、Ｒ^１およびＲ^２の何れか一方とＲ^３およびＲ^４の何れか一方とが環を形成してもよい。ｎは１、２または４の整数を表す。）
【００１６】

（式中、Ｒ^１〜Ｒ^４は、同一若しくは異なっていてもよく、水素原子、アルキル基、アリール基または−ＮＲ^５Ｒ^６で示される基を表わし、Ｒ^５およびＲ^６は、水素原子、炭素数１〜５のアルキル基、フェニル基または−ＮＲ^７ＣＳＮＲ^８Ｒ^９で示される基（但し、Ｒ^７〜Ｒ^９は、水素原子、炭素数１〜５のアルキル基またはフェニル基からなり、それぞれ同一若しくは異なっていてもよい）を表わす。また、Ｒ^１およびＲ^２の何れか一方とＲ^３およびＲ^４の何れか一方とが環を形成してもよい。）
【００１７】

（式中、Ｒ^１はアリーレン基を表し、Ｒ^２はアルキル基、アリール基、ベンジル基、またはシクロへキシル基を表し、Ｒ^１またはＲ^２は、置換基を有していてもよい。）
【００１８】
また、本発明は、第二発明として、基材の少なくとも一方の面に１層以上のインク受容層を設け、該受容層が、バインダーとして水溶性樹脂および／または水分散性樹脂と、無機微粒子と、前記の一般式（４）で表される化合物と、ホウ素化合物と、アクリルアミド−ジアリルアミン塩酸塩共重合体と、硫黄化合物とが含有され、かつ前記無機微粒子の動的光散乱法により測定される平均粒径（ｄ）および多分散指数（μ／＜Γ＞^２）が下記式（３）および式（４）を満たすことを特徴とする被記録媒体を提供する。
１５０ｎｍ≦ｄ≦２５０ｎｍ・・・・式（３）
０．０１≦μ／＜Γ＞^２≦０．２０・・・・式（４）
【００１９】
上記第二発明では、前記硫黄化合物が、前記の一般式（１）〜（３）で表される化合物から選ばれる少なくとも１種の化合物であることが好ましい。
【００２０】
また、本発明は、第三発明として、前記インク受容層がさらにベンゾトリアゾール系化合物を含む前記第一および第二発明の被記録媒体を提供する。
【００２１】
上記インク受容層を有する上記第一〜第三発明の被記録媒体は、画像濃度や色調、インク吸収性などの印字特性に優れ、長期保存における画像の退色、変色および染料のマイグレーションが少なく、白地部の黄変についても抑制された被記録媒体である。
【００２２】
【発明の実施の形態】
次に好ましい実施の形態を挙げて本発明をさらに詳しく説明する。先ず、第一〜第三発明について共通する基本的な材料を説明する。
本発明において使用する基材としては、例えば、フィルム、キャストコート紙、バライタ紙、レジンコート紙（両面がポリオレフィンなどの樹脂で被覆された樹脂被覆紙）などの紙類からなるものが好ましく使用される。前記フィルムとしては、例えば、ポリエチレン、ポリプロピレン、ポリエステル、ポリ乳酸、ポリスチレン、ポリアセテート、ポリ塩化ビニル、酢酸セルロース、ポリエチレンテレフタレート、ポリメチルメタクリレートおよびポリカーボネートなどの透明な熱可塑性樹脂フィルムが挙げられる。
【００２３】
また、その他にも、適度のサイジングが施された紙、無サイズ紙、コート紙、無機物の充填または微細な発泡により不透明化されたフィルムからなるシート状物質（合成紙など）：さらにはガラスまたは金属などからなるシートなどを使用してもよい。また、これら基材とインク受容層との接着強度を向上させるため、基材表面にコロナ放電処理や各種アンダーコート処理を施すことも可能である。
【００２４】
本発明において使用する無機微粒子（Ａ）としては、インク吸収能が高く、発色性に優れ、高品位の画像が形成可能な無機微粒子であることが好ましい。このような無機微粒子としては、例えば、炭酸カルシウム、炭酸マグネシウム、カオリン、クレー、タルク、ハイドロタルサイト、珪酸アルミニウム、珪酸カルシウム、珪酸マグネシウム、ケイソウ土、アルミナ、コロイダルアルミナ、水酸化アルミニウム、ベーマイト構造のアルミナ水和物および擬ベーマイト構造のアルミナ水和物、合成非晶質シリカ、コロイダルシリカ、リトポン、ゼオライトなどを挙げることができ、これらを単独或いは複数種を併用することができる。これらの無機微粒子の中では、水酸化アルミニウム、アルミナおよびベーマイト構造または擬ベーマイト構造のアルミナ水和物の少なくとも１種から選ばれる無機微粒子が好ましく、さらにベーマイト構造または擬ベーマイト構造のアルミナ水和物が好ましくは用いられる。
【００２５】
前記一般式（１）で表わされる化合物において、Ｒ^１およびＲ^２とＸおよびＹは前記と同意義であり、Ｒ^１およびＲ^２がアルキレン基である場合には、炭素数１〜５のものが好ましく、アリーレン基である場合にはフェニレン基またはナフチレン基が好ましい。これらのアルキレン基若しくはアリーレン基は何れも置換基を有していてもよいし、未置換でもよい。また、Ｒ^１およびＲ^２は同一であっても異なっていてもよい。
【００２６】
前記一般式（１）で表される化合物としては、例えば、以下のようなものが挙げられる。

【００２７】
前記一般式（２）で表わされる化合物において、Ｒ^１〜Ｒ^４は前記と同意義であり、Ｒ^１〜Ｒ^４がアルキル基である場合には炭素数１〜１０のものが好ましく、アリール基である場合にはフェニル基、若しくはナフチル基が好ましい。これらのアルキル基若しくはアリール基は何れも置換基を有していてもよいし、未置換でもよい。また、Ｒ^１とＲ^２とは同一であっても異なっていてもよい。
【００２８】
前記一般式（２）で表される化合物としては、例えば、以下のようなものが挙げられる。

【００２９】
前記一般式（３）で表わされる化合物において、Ｒ^１〜Ｒ^９は前記と同意義であり、Ｒ^１〜Ｒ^４がアルキル基である場合は、炭素数１〜１０のものが好ましく、アリール基である場合はフェニル基またはナフチル基が好ましい。これらのアルキル基およびアリール基は何れも未置換でもよいし、置換基を有してもよい。
【００３０】
前記一般式（３）で表わされる化合物としては、具体的には、以下のようなものが挙げられる。先ず、Ｒ^１〜Ｒ^４が、水素原子、アルキル基またはアリール基などである化合物としては、例えば、以下のようなものが挙げられる。

【００３１】
また、一般式（３）において、Ｒ^１〜Ｒ^４の少なくとも１個が、−ＮＲ^５Ｒ^６で表わされる基である化合物としては、例えば、以下のようなものが挙げられる。

【００３２】
さらに一般式（３）で表わされる化合物において、Ｒ^１およびＲ^２の何れか一方とＲ^３およびＲ^４の何れか一方とが環を形成している化合物としては、例えば、以下のようなものが挙げられる。

【００３３】
前記一般式（４）で表わされる化合物においてＲ^１およびＲ^２は前記と同意義であり、Ｒ^１のアリーレン基としてはフェニレン基が好ましい。また、Ｒ^２がアルキル基の場合には炭素数１〜１０のアルキル基が好ましく、アリール基の場合にはフェニル基、またはナフチル基が好ましい。Ｒ^１およびＲ^２のアルキル基、またはアリール基はいずれも置換基を有していてもよい。
【００３４】
前記一般式（４）で表わされる化合物としては、例えば、以下のようなものが挙げられる。

【００３５】
また、前記一般式（１）〜（４）で表される少なくとも１種の化合物の使用量は、インク受容層のインク吸収性や、そこに形成された画像の退色および変色防止効果の観点から、無機微粒子１００質量部当たり０．５〜１５質量部の範囲が好ましく、この範囲であれば印字時にインクの滲みやビーディングの発生がさらに効果的に防止できる。
【００３６】
本発明においては、前記一般式（１）〜（４）で表される少なくとも１種の化合物とともに、ホウ素化合物を使用する。本発明で使用するホウ素化合物とは、ホウ酸若しくはホウ酸塩などのようなホウ素原子を中心とした酸素酸またはその塩であり、具体的には、例えば、オルトホウ酸、メタホウ酸、次ホウ酸、四ホウ酸、五ホウ酸およびそれらの塩が挙げられる。
【００３７】
一般に、ホウ酸は、親水性ポリマーによって形成される皮膜の造膜性、耐水性および皮膜強度を改善するための硬膜剤として使用されている。硬膜剤は、使用するポリマーが持つ反応性基の種類によって様々なものが選択されるが、例えば、ポリビニルアルコール系の樹脂であれば、エポキシ系硬膜剤や、ホウ酸或いは水溶性アルミニウム塩などの無機系硬膜剤が用いられる。
【００３８】
しかし、本発明におけるホウ素化合物の役割は、被記録媒体中に特に前記一般式（１）〜（４）で表される少なくとも１種の化合物とともに含有させた場合に、画像の退色防止効果および変色防止効果を増大することにあり、硬膜剤としての作用に限定した用途とは異なる。
【００３９】
本発明におけるホウ素化合物（Ｄ）の使用量は、前記画像の退色および変色防止に対する相乗効果と、良好な塗工安定性とを両立させるために、無機微粒子１００質量部当たり０．５〜５質量部とすることが好ましい。より好ましくは、無機微粒子１００質量部当たり１〜５質量部で、前記一般式（１）〜（４）で表される少なくとも１種の化合物（Ｂ）とホウ素化合物（Ｄ）の混合質量比が
０．１≦Ｂ／Ｄ≦１５・・・・式（５）
の範囲であることが好ましい。なお、一般式（１）〜（４）で表される少なくとも１種の化合物とホウ素化合物の使用量の比、すなわち、Ｂ／Ｄが０．１未満である場合は、基材上に形成されるインク受容層がひび割れたり、画像の退色防止効果および変色防止効果の相乗効果が期待できなくなる。また、Ｂ／Ｄが１５を超える場合には、塗工液がゲル化したり、塗工安定性が悪くなることがある。
【００４０】
本発明で使用されるアクリルアミド−ジアリルアミン塩酸塩共重合体は、下記一般式（５）で表されるアクリルアミドとジアリルアミン塩酸塩を構成成分とする共重合体である。式中、ジアリルアミンのモル分率（ｍ）は、一般的には０．０１〜０．９９の範囲、好ましくは０．１５〜０．９５の範囲であり、アクリルアミドのモル分率（ｎ）は、一般的には０．９９〜０．０１の範囲、好ましくは０．８５〜０．０５の範囲である。ジアリルアミンのモル分率が０．０１未満になると、インクジェット記録後の画像の耐水性やマイグレーション防止の効果が充分に発揮されないため、ジアリルアミンの量を極端に少なくすることはあまり現実的ではない。

【００４１】
上記共重合体の高分子鎖中のモノマー配列は、ランダム共重合体、交互共重合体、ブロック共重合体、マルチブロック共重合体などの何れの構造でもよい。また、特に分子量や分子量分布も限定されるものではないが、水溶液にした時の粘性を考慮すると、分子量は５，０００〜２００，０００が好ましいといえる。
【００４２】
また、アクリルアミド−ジアリルアミン塩酸塩共重合体は、一般に被記録媒体に形成された画像の耐水性を改善する目的で染料固着剤として使用される。このような染料固着剤はアニオン性の基を持つインクジェット用染料と塩を形成し、水に対して不溶化することで画像の耐水性を向上させる。
【００４３】
しかし、本発明でアクリルアミド−ジアリルアミン塩酸塩共重合体を使用する目的は、画像の耐水性や染料のマイグレーション防止の機能を付与するためだけではなく、前記一般式（１）〜（４）で表される少なくとも１種の化合物とホウ素化合物と同時に使用することで、さらに画像の退色防止効果および変色防止効果を向上させるためである。
【００４４】
以下、本発明の第一発明の特徴を説明する。この第一発明では、インク受容層の形成に使用する材料の配合割合が特徴である。第一発明で使用する前記一般式（１）〜（４）で表される少なくとも１種の化合物（Ｂ）、ホウ素化合物（Ｄ）およびアクリルアミド−ジアリルアミン塩酸塩共重合体（Ｃ）の使用量は、下記式（２）の範囲である。
（Ｂ／Ｄ）：Ｃ＝０．１：５〜１５：０．１・・・・式（２）
前記一般式（１）〜（４）で表される少なくとも１種の化合物とホウ素化合物の使用量の比、すなわち、（Ｂ／Ｄ）とアクリルアミド−ジアリルアミン塩酸塩共重合体の比が、上記の範囲にある場合、画像の変退色防止の効果をさらに向上させると同時に、染料のマイグレーション防止にも効果がある。
【００４５】
ホウ素化合物やアクリルアミド−ジアリルアミン塩酸塩共重合体の使用量は、無機微粒子（Ａ）やバインダーとして用いる水溶性樹脂および／または水分散性樹脂の量によって大きく変化するが、前記一般式（１）〜（４）で表される少なくとも１種の化合物（Ｂ）、アクリルアミド−ジアリルアミン塩酸塩共重合体（Ｃ）および前記ホウ素化合物（Ｄ）の混合質量比、すなわち、（Ｂ／Ｄ）：Ｃ＝０．１：５〜１５：０．１（式２）となる範囲において、４×（Ｂ＋Ｃ＋Ｄ）≦Ａ（式１）、すなわち、Ｂ、ＣおよびＤの合計量を無機微粒子１００質量部当たり２５質量部以下の割合で添加することが好ましい。好ましくは無機微粒子１００質量部当たり（Ｂ＋Ｃ＋Ｄ）が１．５５〜２５質量部の範囲である。（Ｂ＋Ｃ＋Ｄ）の含有量が２５質量部を超える場合は、インク受容層を形成するための塗工液粘度の経時変化が大きくなり、塗工安定性が劣る場合がある。また、（Ｂ＋Ｃ＋Ｄ）が１．５５質量部未満では本発明の目的である画像の変退色防止効果とマイグレーションの抑制効果が十分ではない場合がある。
【００４６】
さらに第一発明においては、前記無機微粒子の平均粒子径が１５０〜２５０ｎｍで、かつ多分散指数（μ／＜Γ＞^２）が０．０１〜０．２０の範囲とすることが好ましく、より好ましくは無機微粒子の平均粒子径が１６０〜２３０ｎｍの範囲で、かつ多分散指数が０．０１〜０．１８の範囲である。このような無機微粒子を使用することで、第一発明の効果に加えて、後記第二発明の効果も同時に得られる
【００４７】
以下、本発明の第二発明の特徴を説明する。この第二発明においては、インク受容層が前記一般式（４）の化合物と硫黄化合物と含み、かつ無機微粒子の形態に特徴を有する。すなわち、第二発明では、無機微粒子（Ａ）の形態としては、高光沢かつ高透明性のインク受容層を得るために、平均粒子径が１５０〜２５０ｎｍで、かつ多分散指数（μ／＜Γ＞^２）が０．０１〜０．２０の範囲とする。より好ましくは無機微粒子の平均粒子径が１６０〜２３０ｎｍの範囲で、かつ多分散指数が０．０１〜０．１８の範囲である。無機微粒子の平均粒子径が１５０ｎｍより小さい場合には、インク受容層のインク吸収性が低下し、インクの吐出量が多いプリンターや、高速出力するプリンターで印字する際に滲みやビーディングが発生するおそれがある。一方、平均粒子径が２５０ｎｍより大きい場合にはインク受容層の透明性が低下するとともに、耐ガス性が低下することがある。また、多分散指数が０．２０を超える場合も、平均粒子径の場合と同様にインク受容層の透明性、印字濃度および光沢が低下し、印字後の画像がくすむおそれがある。
上記第二発明では、前記硫黄化合物として、前記一般式（１）〜（３）で表される化合物から選ばれる少なくとも１種の化合物を使用することが好ましい。
【００４８】
なお、第二発明でいう平均粒子径と多分散指数は動的光散乱法によって測定され、「高分子の構造（２）散乱実験と形態観察　第１章　光散乱」（共立出版　高分子学会編）、或いはＪ．Ｃｈｅｍ．Ｐｈｙｓ．，７０（Ｂ），１５　Ａｐｌ．，３９６５（１９７９）に記載のキュムラント法を用いた解析から求めることができる。動的光散乱法は異なる粒子径を持つ微粒子が混在している場合、散乱光からの時間相関関数の減衰に分布を有する。この時間相関関数をキュムラント法を用いて解析することで、減衰速度の平均（＜Γ＞）と分散（μ）が求まる。減衰速度（Γ）は粒子の拡散係数と散乱ベクトルの関数で表されるため、ストークス−アインシュタイン式を用いて、流体力学的平均粒子径を求めることができる。従って、減衰速度の分散（μ）を平均の二乗（＜Γ＞^２）で除した多分散指数（μ／＜Γ＞^２）は、粒子径の散らばりの度合いを表しており、値が０に近づく程、粒子径の分布は狭くなることを意味する。本発明で定義される平均粒子径および多分散指数は、例えば、レーザー粒径解析装置　ＰＡＲＩＩＩ（大塚電子（株）製）などを用いて容易に測定することができる。
【００４９】
以下、本発明の第三発明を説明する。該第三発明は、前記第一発明および第二発明の被記録媒体のインク受容層が、さらにベンゾトリアゾール系化合物を含有することを特徴とする。第三発明に用いられるベンゾトリアゾール系化合物の具体例としては、例えば、２−（２−Ｈｙｄｒｏｘｙ−５−ｍｅｔｈｙｌｐｈｅｎｙｌ）ｂｅｎｚｏｔｒｉａｚｏｌｅ（Ｓｕｍｉｓｏｒｂ２００：住友化学）、２−［２−Ｈｙｄｒｏｘｙ−３−（３，４，５，６−ｔｅｔｒａｈｙｄｒｏｐｈｔｈａｌｉｍｉｄｅ−ｍｅｔｈｙｌ）−５−ｍｅｔｈｙｌｐｈｅｎｙｌ］ｂｅｎｚｏｔｒｉａｚｏｌｅ（Ｓｕｍｉｓｏｒｂ２５０：住友化学）、２−（３−ｔｅｒｔ−ｂｕｔｙｌ−２−Ｈｙｄｒｏｘｙ−５−ｍｅｔｈｙｌｐｈｅｎｙｌ）−５−ｃｈｌｏｒｏｂｅｎｚｏｔｒｉａｚｏｌｅ（Ｓｕｍｉｓｏｒｂ３００：住友化学）、２−（２−Ｈｙｄｒｏｘｙ−５−ｔｅｒｔ−ｏｃｔｙｌｐｈｅｎｙｌ）ｂｅｎｚｏｔｒｉａｚｏｌｅ（Ｓｕｍｉｓｏｒｂ３４０：住友化学）、Ｂｅｎｚｏｔｒｉａｚｏｌｅ（関東化学）、２−（３−ｔ−ブチル−５−メチル−２−ヒドロキシフェニル）−５−クロロベンゾトリアゾール（ＫＥＭＩＳＯＲＢ７３：ケミプロ化成）、２−［２−ヒドロキシ−３，５−ビス（α，α−ジメチルベンジル）フェニル］−２Ｈ−ベンゾトリアゾール（ＴＩＮＵＶＩＮ２３４：チバ・スペシヤリティケミカル）、２−（３，５−ジ−ｔ−ブチル−２−ヒドロキシフェニル）ベンゾトリアゾール（ＴＩＮＵＶＩＮ　３２０：チバ・スペシヤリティケミカル）、ヒドロキシフェニルベンゾトリアゾール誘導体（ＴＩＮＵＶＩＮ　５７１：チバ・スペシヤリティケミカル）などの市販のものが挙げられる。なお、本発明に使用されるベンゾトリアゾール系化合物はこれらに限定されるものではなく、単独あるいは複数種混合して用いることができる。
【００５０】
上記ベンゾトリアゾール系化合物の使用量は、無機顔料１００質量部当たり０．０５〜３質量部とすることが好ましく、この範囲であれば、前述した一般式（１）〜（４）で表される少なくとも１種の化合物とホウ素化合物およびアクリルアミド−ジアリルアミン塩酸塩共重合体が共存した場合にも、画像の耐光性および白地部分の黄変防止効果が損なわれることはない。
【００５１】
以下、第一〜第三発明の他の共通事項を説明する。本発明において、上記各成分の混合質量比は、前記式（１）および式（２）を満たすとともに、全体的にみて以下の範囲が好適である。
・無機微粒子・・・１００質量部
・水溶性樹脂および／または水分散性樹脂・・・３．３３〜１００質量部
・前記一般式（１）〜（４）で表される少なくとも１種の化合物・・・０．５〜１５質量部
・アクリルアミド−ジアリルアミン塩酸塩共重合体・・・０．０５〜５質量部
・ホウ素化合物・・・１〜５質量部
・ベンゾトリアゾール系化合物・・・０．０５〜３質量部
【００５２】
本発明の被記録媒体は、以上の成分を含有する塗工液を調製し、該塗工液を基材の表面に塗工してインク受容層を形成することで得られるが、このインク受容層は、前記無機微粒子と少量の水溶性樹脂および／または水分散性樹脂から形成される空隙を有するものが好ましい。より微細な空隙が形成できるという点では、無機微粒子として水酸化アルミニウム、アルミナ、ベーマイト構造若しくは擬ベーマイト構造のアルミナ水和物を用いるのが好ましい。特に、ＢＥＴ比表面積が５０ｍ^２／ｇ以上の、アルミナ、ベーマイト構造または擬ベーマイト構造のアルミナ水和物が好ましい。
本発明に用いられるアルミナ水和物としては、下記一般式（６）により表されるものが使用できる。
Ａｌ_２Ｏ_３−ｎ（ＯＨ）_２ｎ・ｍＨ_２Ｏ・・・・一般式（６）
式中、ｎは０、１、２または３の整数の内の何れかを表し、ｍは０〜１０、好ましくは０〜５の値を表す。ｍＨ_２Ｏは多くの場合結晶格子の形成に関与しない脱離可能な水相を表すものであるため、ｍは整数でない値をとることができる。また、この種のアルミナ水和物をか焼するとｍは０の値に達することがありうる。
【００５３】
一般にベーマイト構造を示すアルミナ水和物の結晶は、その（０２０）面が巨大平面を形成する層状化合物であり、Ｘ線回折図形に特有の回折ピークを示す。ベーマイト構造としては、完全ベーマイトの他に擬ベーマイトと称する、過剰な水を（０２０）面の層間に含んだ構造を取ることもできる。この擬ベーマイトのＸ線回折図形は完全なベーマイトよりも幅広な回折ピークを示す。完全ベーマイトと擬ベーマイトは明確に区別できるものではないので、以下特に断らない限り、両者を含めてベーマイト構造を示すアルミナ水和物という。
【００５４】
本発明で被記録媒体に含有されるベーマイト構造を有するアルミナ水和物の製造方法としては、特に限定されないが、ベーマイト構造をもつアルミナ水和物を製造できる方法であれば、例えば、アルミニウムアルコキシドの加水分解またはアルミン酸ナトリウムを加水分解するなどの公知の方法で製造することもできる。
【００５５】
特開昭５６−１２０５０８号公報に開示されているように、Ｘ線回折的に無定形のアルミナ水和物を、水の存在下で５０℃以上で加熱処理することによってベーマイト構造に変えて用いることができる。特に好ましく用いることができる方法は、長鎖のアルミニウムアルコキシドに対して酸を添加して加水分解および解膠を行うことによってアルミナ水和物を得る方法である。
【００５６】
ここで、長鎖のアルミニウムアルコキシドとは、例えば、炭素数が５以上のアルコキシドであり、さらに炭素数１２〜２２のアルコキシドを用いると、後述するようにアルコール分の除去およびアルミナ水和物の形状制御が容易になるため好ましい。
【００５７】
添加する酸としては有機酸、無機酸の中から１種または２種以上を自由に選択して用いることができるが、加水分解の反応効率および得られたアルミナ水和物の形状制御や分散性の点で硝酸が最も好ましい。この工程の後に水熱合成などを行って粒子径を制御することも可能である。硝酸を含むアルミナ水和物分散液を用いて水熱合成を行うと、水溶液中の硝酸がアルミナ水和物表面に硝酸根として取り込まれて水分散性を向上させることができる。
【００５８】
上記方法には、アルミナヒドロゲルやカチオン性アルミナを製造する方法と比較して、各種イオンなどの不純物が混入しにくいという利点がある。さらに長鎖のアルミニウムアルコキシドは、加水分解後のアルコールが除去し易いため、アルミニウムイソプロポキシドなどの短鎖のアルコキシドを用いる場合と比較して、アルミナ水和物の脱アルコールを完全に行なうことができるという利点がある。
【００５９】
また、前記方法で合成された無機微粒子の分散液をさらに粉砕分散機などを用いた物理的な手段で所望とする粒径にすることも可能である。本発明で用いることのできる粉砕分散機としては、公知の様々な分散機を使用することが可能で、例えば、高圧ホモジナイザー、超音波ホモジナイザー、湿式メディア型粉砕機（サンドミル、ボールミル）、連続式高速撹拌型分散機、超音波分散機などが挙げられる。
【００６０】
具体的にはマントンゴーリンホモジナイザー、ソノレータ（同栄商事社製）、マイクロフルイタイザー（みずほ工業社製）、ナノマイザー（月島機械社製）、アルティマイザー（伊藤忠産機社製）、パールミル、グレンミル、トルネード（浅田鉄鋼社製）、ビスコミル（アイメックス社製）、マイティーミル、ＲＳミル、ＳΓミル（井上製作所製）、荏原マイルダー（荏原製作所製）、ファインフローミル、キャビトロン（大平洋機工社製）などが挙げられる。
【００６１】
本発明の被記録媒体は、前記無機微粒子（Ａ）、前記一般式（１）〜（４）で表される少なくとも１種の化合物（Ｂ）、アクリルアミド−ジアリルアミン塩酸塩共重合体（Ｃ）およびホウ素化合物からなる組成物を、必要に応じた量の水溶性樹脂および水性媒体とともに混合して塗工液を調製し、これを基材の表面に塗布し乾燥させてインク受容層を形成することで得られる。
【００６２】
本発明の被記録媒体の構成としては、コート紙およびコートフィルムのように、基材上にインク受容層を設けたもの、基材の表面近傍に塗工液の一部若しくは大部分が含浸されてインク受容層が形成されたもの、或いは塗工液を基材表面に微量塗工してインク受容層を形成させた構成などが選択できる。本発明では、これらの構成も「基材の表面にインク受容層が形成された」ものとして包含する。
【００６３】
前記塗工液に含有させる水溶性樹脂としては、水性または水分散性の高分子化合物があり、例えば、澱粉、ゼラチン、カゼインおよびそれらの変性物、メチルセルロース、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などのセルロース誘導体、完全または部分ケン化のポリビニルアルコールまたはその変性物（カチオン変性、アニオン変性、シラノール変性など）、尿素系樹脂、メラミン系樹脂、エポキシ系樹脂、エピクロルヒドリン系樹脂、ポリウレタン系樹脂、ポリエチレンイミン系樹脂、ポリアミド系樹脂、ポリビニルピロリドン系樹脂、ポリビニルブチラール系樹脂、ポリ（メタ）アクリル酸またはその共重合体、アクリルアミド系樹脂、無水マレイン酸系共重合体、ポリエステル系樹脂、ＳＢＲラテックス、ＮＢＲラテックス、メチルメタクリレート−ブタジエン共重合体ラテックス、アクリル酸エステル共重合体などのアクリル系重合体ラテックス、エチレン−酢酸ビニル共重合体などのビニル系重合体ラテックスおよびこれらの各種重合体ラテックスにカチオン性基またはアニオン性基を付与した官能基変性重合体ラテックス類などが挙げられる。
【００６４】
特に好ましいのは、ポリ酢酸ビニルを加水分解して得られるポリビニルアルコールで、平均重合度が３００〜５，０００のものである。ケン化度は７０〜１００％未満のものが好ましく、８０〜９９．５％のものが特に好ましい。また、これらの水溶性または水分散性樹脂は単独或いは複数種混合して用いることができる。
【００６５】
塗工液中の無機微粒子と水溶性樹脂の混合質量比は、好ましくは１：１〜３０：１、より好ましくは３：１〜２０：１の範囲である。水溶性樹脂の量がこれらの範囲内であれば、形成されたインク受容層のひび割れや粉落ちが発生し難くなり、インク吸収性も良い。
【００６６】
また、塗工液の水性媒体としては、水または水に混合可能な有機溶剤との混合溶液であれば特に制限はない。水に混合可能な有機溶剤としては、例えば、メタノール、エタノール、プロパノールなどのアルコール類：エチレングリコールモノメチルエーテル、エチレングリコールジメチルエーテルなどの多価アルコールの低級アルキルエーテル類：アセトン、メチルエチルケトンなどのケトン類：テトラヒドロフランなどのエーテル類が挙げられる。
【００６７】
インク受容層を形成するための塗工液中の固形分濃度は、基材上にインク受容層を形成できる程度の粘度であれば特に制限はないが、塗工液全質量に対して５〜５０質量％が好ましい。固形分濃度が５質量％未満の場合は、インク受容層の膜厚を厚くするのに塗工量を増やす必要があり、乾燥に多くの時間とエネルギーを必要とすることから非経済的となる場合がある。また、５０質量％を越えると塗工液の粘度が高くなり、塗工性が低下する場合がある。
【００６８】
また、前記塗工液には、本発明の効果を妨げない範囲内で各種添加剤を配合することができる。このような添加剤としては、界面活性剤、顔料分散剤、増粘剤、消泡剤、インク定着剤、ドット調整剤、着色剤、蛍光増白剤、酸化防止剤、紫外線吸収剤、防腐剤、ｐＨ調整剤などを挙げることができる。
【００６９】
調製された塗工液を基材上に塗布する方法としては、公知の任意の塗工法が適用でき、例えば、ブレードコーティング法、エアーナイフコーティング法、カーテンコーティング法、スロットダイコーティング法、バーコーティング法、グラビアコーティング法、ロールコーティング法などの塗布方式により、乾燥塗布量が０．５〜６０ｇ／ｍ^２となるように塗布される。その後、熱風乾燥機、熱ドラム、遠赤外線乾燥機などの乾燥装置を用いて乾燥することで、インク受容層を形成することができる。なお、インク受容層は、無機微粒子と樹脂およびその他の添加剤の組成比を変更して形成してもよく、基材の片面若しくは両面に形成することも可能である。また、画像の解像度および搬送性などを向上させる目的で、スーパーカレンダー、ソフトカレンダーなどの装置を用いて平滑化処理してもよい。
【００７０】
塗工液の基材上への塗工量として好ましい範囲は、固形分換算で０．５〜６０ｇ／ｍ^２であり、より好ましい範囲は５〜５５ｇ／ｍ^２である。塗工量が０．５ｇ／ｍ^２未満の場合は、形成されたインク受容層がインクの水分を十分に吸収できず、インクが流れたり、画像が滲んだりする場合があり、６０ｇ／ｍ^２を超えると、乾燥時にカールが発生したり、印字性能に期待されるほど顕著な効果が現れない場合がある。
【００７１】
以上の如き本発明の被記録媒体が印字品位に優れ、特に長期保存における画像の退色および変色に対し優れた抑制効果を示した理由については明確ではないが、おそらく前記一般式（１）〜（４）で表される少なくとも１種の化合物とアクリルアミド−ジアリルアミン塩酸塩共重合体とホウ素化合物との間で何らかの相互作用が生じ、このような効果を発現したものと考えられる。
【００７２】
なお、本発明の被記録媒体に記録する際に使用するインクは特に限定されないが、色材として染料または顔料を使用し、媒体として水と水溶性有機溶剤との混合物を使用し、該媒体に染料または顔料を溶解または分散させた一般的なインクジェット記録用の水性インクの使用が好ましい。
【００７３】
前記被記録媒体に上記インクを付与して画像形成を行う方法としては、インクジェット記録方法が特に好適であり、このインクジェット記録方法としてはインクをノズルより効果的に離脱させて、被記録媒体にインクを付与し得る方法であれば如何なる方法でもよい。特に特開昭５４−５９９３６号公報などに記載されている方法で、熱エネルギーの作用を受けたインクが急激な体積変化を生じ、この状態変化による作用力によって、インクをノズルから吐出させるインクジェット方式は有効に使用することができる。
【００７４】
【実施例】
以下、実施例により本発明を具体的に説明する。なお、以下の実施例中、「部」および「％」は特に記載が無い限り質量基準である。
＜アルミナ水和物の製造＞
米国特許第４，２４２，２７１号明細書に記載された方法でアルミニウムドデキシドを製造した。次に米国特許第４，２０２，８７０号明細書に記載された方法で、前記アルミニウムドデキシドを加水分解してアルミナスラリーを製造した。このアルミナスラリーをベーマイト構造を有するアルミナ水和物固形分が７．７％になるまで水を加えた。アルミナスラリーのｐＨは９．４であった。３．９％の硝酸溶液を加えてｐＨを調整した。
【００７５】
次に、オートクレーブを用いて、熟成前のｐＨ：６．０、熟成温度：１５０℃、熟成時間：６時間にて熟成を行いコロイダルゾルを得た。このコロイダルゾルを入口温度８７℃でスプレードライしてアルミナ水和物粉末としたが、得られた粉末は粒子形状が平板状で、結晶構造がベーマイト構造であるアルミナ水和物であった。さらに、イオン交換水中に、前記ベーマイト構造を有するアルミナ水和物を１９％の濃度に加えて混合することにより、アルミナ水和物分散液を調製した。
【００７６】
前記方法で得られた分散液を超音波ホモジナイザーＭＵＳ−６００ＣＣＶＰ−１２（（株）日本精機製作所製）を用いて幾つかの条件で再分散後、遠心分離操作により粗大粒子を取り除き、イオン交換水を加えることで濃度１７％のアルミナ水和物分散液Ａ〜Ｅを調製した。また、アルミナ水和物分散液Ｆに関しては遠心分離操作を行わなかった。このようにして得られたアルミナ水和物分散液の平均粒子径（ｎｍ）と多分散指数（μ／＜Γ＞^２）はレーザー粒径解析装置　ＰＡＲＩＩＩ（大塚電子（株）製）を用いて測定した。下記表１にその結果を示す。
【００７７】

【００７８】
＜評価１：退色・変色抑制効果についての評価方法＞
オゾン暴露による退色・変色を、インクジェット記録装置（ＢＪ　Ｆ９００、キヤノン（株）製）を用いてイエロー（Ｙ）、マゼンタ（Ｍ）、シアン（Ｃ）およびブラック（Ｂｋ）インクを単色で、かつインク量１００％でベタ印字した被記録媒体をオゾン暴露試験機（スガ試験機社製、特注品）に入れて、４０℃・５５％ＲＨの条件下で濃度３ｐｐｍのオゾンに２時間暴露し、保存前後で印字部の色味変化を目視評価した。各色で色味に差異が認められない場合は○、何れかの色で色味に僅かな差異が認められた場合は△、何れかの色で大きな差異が認められた場合は×とした。
【００７９】
＜評価２：マイグレーション防止効果についての評価方法＞
インクジェット記録装置（ＢＪ　Ｆ９００、キヤノン（株）製）を用いてＹ、Ｍ、ＣおよびＢｋインクを単色で、かつインク量１００％でベタ印字した被記録媒体を３０℃、８０％ＲＨの環境に１週間保存した時に、保存前後で染料がマイグレーションした度合いを目視評価した。各色でマイグレーションが起きていないものを〇、何れかの色でマイグレーションが僅かに起きているものを△、何れかの色でマイグレーションの度合いが大きいものを×とした。
【００８０】
＜評価３：インク吸収性評価方法＞
インクジェット記録装置（ＢＪ　Ｆ９００、キヤノン（株）製）を用いて単色から４色までのベタ印字を行った。印字後の被記録媒体表面のインクの乾燥状態を記録部に指で触れてインク吸収性を調べた。単色ベタ印字でのインク量を１００％とした。インク量３００％（３色混合）でインクが指に付着しないものを◎、インク量２００％（２色混合）でインクが指に付着しないものを○、インク量１００％でインクが指に付着しないものを△、同１００％でインクが指に付着するものを×とした。
【００８１】
＜評価４：白地部黄変の評価方法：第三発明においてのみ行った。＞
被記録媒体の白地部黄変の程度を評価する目的で、原因の一つとして考えられるＢＨＴ二量体（４，４’−メチレンビス−２，６−ジ−ｔ−ブチルフェノール）のエタノール１％溶解液を、被記録媒体に固形分量として０．５ｇ／ｍ^２となるように滴下して自然乾燥し、２０℃、６５％ＲＨの条件下で２４時間放置した後、目視で着色の具合を評価した。殆んど着色が認められないものを○、若干黄色く着色したものを△、著しく黄色く着色したものを×とした。
【００８２】
「第一発明」
＜実施例１＞
前記のアルミナ水和物分散液Ｂを１００部（固形分１７部）に、β−チオジグリコール０．８２部（アルミナ水和物に対して４．８％）および３％ホウ酸水溶液を固形分換算で０．６８部（アルミナ水和物に対して４％）およびアクリルアミド−ジアリルアミン塩酸塩共重合体として、スミレーズレジン１００１（住友化学（株）製）を固形分換算で０．１７部（アルミナ水和物に対して１％）加えたものと、ポリビニルアルコール（ＰＶＡ−２２４、クラレ社製）１．７部を水１５．３部に溶解したものを混合して塗工液を調製した。次にレジンコート紙を基材とし、この基材上に先程調製した塗工液を乾燥塗布量３５ｇ／ｍ^２となるようにバーコート法にて塗工し、１００℃、３０分間熱風乾燥してインク受容層を形成させた。このようにして得られた被記録媒体に、インクジェット記録装置（ＢＪ　Ｆ９００、キヤノン（株）製）を用いて単色から４色までのベタ印字を行い、前記評価１〜評価３を行った。
【００８３】
＜実施例２＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、ホウ酸の添加量を固形分換算で０．３４部（アルミナ水和物に対して２％）およびスミレーズレジン１００１の添加量を固形分換算で０．０８５部（アルミナ水和物に対して０．５％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００８４】
＜実施例３＞
前記のアルミナ水和物分散液Ｄを１００部（固形分１７部）に、３％ホウ酸水溶液を固形分換算で０．１７部（アルミナ水和物に対して１％）およびアクリルアミド−ジアリルアミン塩酸塩共重合体として、スミレーズレジン１００１（住友化学（株）製）を固形分換算で０．０１７部（アルミナ水和物に対して０．１％）加えたものと、ポリビニルアルコール（ＰＶＡ−２２４、クラレ社製）１．７部を水１５．３部に溶解したものを混合して塗工液を調製した。次にレジンコート紙を基材とし、この基材上に先程調製した塗工液を乾燥塗布量３５ｇ／ｍ^２となるようにバーコート法にて塗工し、１００℃、３０分間熱風乾燥してインク受容層を形成させた。次ぎにテトラメチルチウラムモノスルフィド１部をメタノール４０部に溶解した溶液を、先に作成したインク受容層上にアルミナ水和物に対して８．２％添加されるように、オーバーコートして被記録媒体を作製し、前記評価を行った。
【００８５】
＜実施例４＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｅに代え、β−チオジグリコールの添加量を２．５５部（アルミナ水和物に対して１５％）添加し、ホウ酸の添加量を固形分換算で０．１７部（アルミナ水和物に対して１％）およびスミレーズレジン１００１の添加量を固形分換算で０．５１部（アルミナ水和物に対して３％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００８６】
＜実施例５＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、β−チオジグリコールの代わりに３，３’−チオジプロピオン酸を１．２１部（アルミナ水和物に対して７．１％）、ホウ酸の添加量を固形分換算で０．１７部（アルミナ水和物に対して１％）およびスミレーズレジン１００１の添加量を固形分換算で０．３４部（アルミナ水和物に対して２％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００８７】
＜実施例６＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、β−チオジグリコールの代わりに２，２’−チオジグリコール酸を２．５５部（アルミナ水和物に対して１５％）、ホウ酸の添加量を固形分換算で０．８５部（アルミナ水和物に対して５％）およびスミレーズレジン１００１の添加量を固形分換算で０．５１部（アルミナ水和物に対して３％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００８８】
＜実施例７＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、β−チオジグリコールの代わりにＮ，Ｎ’−ジエチルチオ尿素を０．３４部（アルミナ水和物に対して２％）、ホウ酸の添加量を固形分換算で０．３４部（アルミナ水和物に対して２％）およびスミレーズレジン１００１の添加量を固形分換算で０．０８５部（アルミナ水和物に対して０．５％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００８９】
＜実施例８＞
実施例１においてアルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、β−チオジグリコールの代わりにチオ尿素を０．１７部（アルミナ水和物に対して１％）、ホウ酸の添加量を固形分換算で０．１７部（アルミナ水和物に対して１％）およびスミレーズレジン１００１の添加量を固形分換算で０．０１７部（アルミナ水和物に対して０．１％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【００９０】
＜実施例９＞
実施例７においてアルミナ水和物分散液Ｃをアルミナ水和物分散液Ｆに代えた以外は、実施例７と同様にして被記録媒体を作製し、前記評価を行った。
＜実施例１０＞
実施例７においてアルミナ水和物分散液Ｃをアルミナ水和物分散液Ａに代えた以外は、実施例７と同様にして被記録媒体を作製し、前記評価を行った。
【００９１】
＜比較例１＞
実施例２において、スミレーズレジン１００１を添加しなかった以外は、実施例２と同様にして被記録媒体を作製し、前記評価を行った。
＜比較例２＞
実施例２において、β−チオジグリコールを添加しなかった以外は、実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【００９２】
＜比較例３＞
実施例２において、β−チオジグリコールとスミレーズレジン１００１を添加しなかった以外は、実施例２と同様にして被記録媒体を作製し、前記評価を行った。
＜比較例４＞
実施例２において、スミレーズレジン１００１の代わりにＰＡＡ−ＨＣｌ−３Ｌ（日東紡社製、ポリアリルアミン塩酸塩）を固形分換算で０．０８５部（アルミナ水和物に対して０．５％）添加した以外は、実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【００９３】
＜比較例５＞
実施例２において、スミレーズレジン１００１の代わりにサンフィックス４１４（三洋化成工業（株）製、ポリアルキレンポリアミン・ジシアンジアミド系重縮合物）を固形分換算で０．０８５部（アルミナ水和物に対して０．５％）添加した以外は、実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【００９４】
＜比較例６＞
実施例２において、ホウ酸を添加しなかった以外は実施例２と同様にして被記録媒体を作製し、前記評価を行った。
＜比較例７＞
実施例３においてテトラメチルチウラムモノスルフィドの添加量を３．４部（アルミナ水和物に対して２０％）、ホウ酸の添加量を０．５１部（アルミナ水和物に対して３％）およびスミレーズレジン１００１の添加量を０．５１部（アルミナ水和物に対して３％）とした以外は実施例３と同様にして被記録媒体を作製し、前記評価を行った。
【００９５】
＜比較例８＞
実施例２において、β−チオジグリコールの添加量を１．７部（アルミナ水和物に対して１０％）、ホウ酸の添加量を１．０２部（アルミナ水和物に対して６％）およびスミレーズレジン１００１の添加量を２．５０部（アルミナ水和物に対して１４．７％）とした以外は実施例２と同様にして塗工液の調製を行ったが、塗工液がゲル化したため被記録媒体を作製することができなかった。
【００９６】
＜比較例９＞
実施例２においてスミレーズレジン１００１の添加量を３．００部（アルミナ水和物に対して１７．６％）とした以外は実施例２と同様にして塗工液の調製を行ったが、塗工液がゲル化したため被記録媒体を作製することができなかった。
以上の実施例および比較例の評価結果を下記表２−１に示す。
【００９７】

【００９８】
以上の実施例および比較例から明らかなように、バインダー、無機微粒子、前記一般式（１）〜（４）で表される少なくとも１種の化合物、アクリルアミド−ジアリルアミン塩酸塩共重合体およびホウ素化合物を、インク受容層に特定の配合割合で同時に含有した被記録媒体に画像を記録した場合、室内での画像の堅牢性を左右する主たる原因であると考えられる大気中の窒素酸化物、硫黄酸化物、オゾンなどによる画像の変色や退色および高温高湿環境下における印字後の染料のマイグレーションを効果的に防止することができた。
【００９９】
「第二発明」
＜実施例１＞
第一発明の実施例１の被記録媒体のインク受容層の表面に、ＶＩＯＳＯＲＢ９０（ｐ−ｔ−ブチルフェニルサリシレート、共同薬品株式会社製）５部をエタノール９５部に溶解した溶液を、アルミナ水和物に対して３．０％添加されるように、オーバーコートして被記録媒体を作製した。このようにして得られた被記録媒体に、インクジェット記録装置（ＢＪ　Ｆ８５０、キヤノン株式会社製）を用いて単色から４色までのベタ印字を行い、前記評価を行った。
【０１００】
＜実施例２＞
実施例１において、アルミナ水和物分散液Ｂをアルミナ水和物分散液Ｃに代え、ホウ酸の添加量を０．３４部（アルミナ水和物に対して２．０％）、スミレーズレジン１００１の添加量を０．０８５部（アルミナ水和物に対して０．５％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して３％となるようにした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１０１】
＜実施例３＞
第一発明の実施例３の被記録媒体のインク受容層の表面に、さらにＶＩＯＳＯＲＢ９０（ｐ−ｔ−ブチルフェニルサリシレート、共同薬品株式会社製）５部をエタノール９５部に溶解した溶液を、インク受容層上にアルミナ水和物に対して１．０％添加されるように、オーバーコートして被記録媒体を作製し、前記評価を行った。
【０１０２】
＜実施例４＞
実施例１において、アルミナ水和物分散液Ｂをアルミナ水和物分散液Ｅに代え、β−チオジグリコールの添加量を２．５５部（アルミナ水和物に対して１５％）、ホウ酸の添加量を０．１７部（アルミナ水和物に対して１％）、スミレーズレジン１００１の添加量を０．５１部（アルミナ水和物に対して３％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して４．８％となるようにした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１０３】
＜実施例５＞
実施例２において、β−チオジグリコールの代わりに３，３’−チオジプロピオン酸を１．２１部（アルミナ水和物に対して７．１％）添加し、ホウ酸の添加量を０．１７部（アルミナ水和物に対して１％）、スミレーズレジン１００１の添加量を０．３４部（アルミナ水和物に対して２％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して３．０％となるようにした以外は実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１０４】
＜実施例６＞
実施例２において、β−チオジグリコールの代わりに２，２’−チオジグリコール酸を２．５５部（アルミナ水和物に対して１５％）添加し、ホウ酸の添加量を０．８５部（アルミナ水和物に対して５％）、スミレーズレジン１００１の添加量を０．５１部（アルミナ水和物に対して３％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して３．０％となるようにした以外は実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１０５】
＜実施例７＞
実施例２において、β−チオジグリコールの代わりに１，３−ジエチル−２−チオウレアを０．３４部（アルミナ水和物に対して２％）添加し、ホウ酸の添加量を０．３４部（アルミナ水和物に対して２％）、スミレーズレジン１００１の添加量を０．０８５部（アルミナ水和物に対して０．５％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して３．０％となるようにした以外は実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１０６】
＜実施例８＞
実施例２において、β−チオジグリコールの代わりにチオウレアを０．１７部（アルミナ水和物に対して１％）添加し、ホウ酸の添加量を０．１７部（アルミナ水和物に対して１％）、スミレーズレジン１００１の添加量を０．０１７部（アルミナ水和物に対して０．１％）、インク受容層にオーバーコートするＶＩＯＳＯＲＢ９０の添加量をアルミナ水和物に対して３．０％となるようにした以外は実施例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１０７】
＜比較例１＞
実施例７において、スミレーズレジン１００１を添加せず、１，３−ジエチル−２−チオウレアの添加量を０．８２部（アルミナ水和物に対して４．８％）とした以外は実施例７と同様にして被記録媒体を作製し、前記評価を行った。
【０１０８】
＜比較例２＞
比較例１において、スミレーズレジン１００１を０．０８５部（アルミナ水和物に対して０．５％）添加し、ＶＩＯＳＯＲＢ９０の代わりにＳＥＥＳＯＲＢ１００（ベンゾフェノン系紫外線吸収剤；シプロ化成株式会社製）を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１０９】
＜比較例３＞
比較例２において、ＶＩＯＳＯＲＢ９０の代わりにアデカスタブＬ７７（ヒンダードアミン系光安定剤、旭電化工業株式会社製）を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１１０】
＜比較例４＞
アルミナ水和物分散液Ｃを１００部（固形分１７部）に、１，３’−ジエチル−２−チオウレア０．８２部（アルミナ水和物に対して４．８％）、ニードラルＵ−１５（酸化セリウム　固形分濃度１５％；多木化学株式会社製）を固形分換算で０．５１部（アルミナ水和物に対して３％）、３％ホウ酸水溶液を固形分換算で０．３４部（アルミナ水和物に対して２％）、およびスミレーズレジン１００１を固形分換算で０．０８５部（アルミナ水和物に対して０．５％）加えたものと、ポリビニルアルコール（ＰＶＡ−２３５、クラレ株式会社製）１．７部を水１５．３部に溶解したものを混合して塗工液を調製した。次にレジンコート紙を基材とし、この基材上に先程調製した塗工液を乾燥塗布量４０ｇ／ｍ^２となるようにバーコート法にて塗工し、１００℃で３０分間熱風乾燥してインク受容層を形成して被記録媒体を作製した。しかし被記録媒体が黄色く着色してしまったため、前記評価は行わなかった。
【０１１１】
＜比較例５＞
比較例２において、ホウ酸を添加せず、ＳＥＥＳＯＲＢ１００の代わりにＶＩＯＳＯＲＢ９０を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１１２】
＜比較例６＞
比較例２において、１，３’−ジエチル−２−チオウレアを添加せず、ＳＥＥＳＯＲＢ１００の代わりにＶＩＯＳＯＲＢ９０を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１１３】
＜比較例７＞
比較例２において、ＳＥＥＳＯＲＢ１００を添加しなかった以外は比較例２と同様にして被記録媒体を作製し、前記評価を行った。
【０１１４】
＜比較例８＞
比較例７において、アルミナ水和物分散液Ｃの代わりにアルミナ水和物分散液Ｆを用い、ＶＩＯＳＯＲＢ９０を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例７と同様にして被記録媒体を作製し、前記評価を行った。
【０１１５】
＜比較例９＞
比較例７において、アルミナ水和物分散液Ｃの代わりにアルミナ水和物分散液Ａを用い、ＶＩＯＳＯＲＢ９０を５部エタノールに溶解した溶液を固形分換算でアルミナ水和物に対して３％添加されるようにオーバーコートした以外は比較例７と同様にして被記録媒体を作製し、前記評価を行った。
以上の実施例および比較例の評価結果を下記表２−２に示す。
【０１１６】

【０１１７】
以上の実施例および比較例から明らかなように、特定の平均粒径および多分散指数の無機微粒子、前記一般式（４）で表わされる化合物、ホウ素化合物、アクリルアミド−ジアリルアミン塩酸塩共重合体および硫黄化合物をインク受容層に同時に含有した被記録媒体に画像を記録した場合、室内での画像の堅牢性を左右する主たる原因であると考えられる大気中の窒素酸化物、硫黄酸化物、オゾンなどによる画像の変退色と光による変退色を効果的に防止することができた。特に硫黄系化合物を単独で用いた時よりも、前記一般式（４）で表される化合物をインク受容層中に含有させたときに、さらに耐ガス性を向上させた被記録媒体を作製することができた。
【０１１８】
「第三発明」
＜実施例１＞
前記アルミナ水和物分散液Ｃ１００部（固形分１７部）に、Ｎ，Ｎ’−ジエチルチオ尿素０．５１部（アルミナ水和物に対して３％）、３％ホウ酸水溶液を固形分換算で０．３４部（アルミナ水和物に対して２％）、アクリルアミド−ジアリルアミン塩酸塩共重合体として、スミレーズレジン１００１（住友化学株式会社製）を固形分換算で０．３４部（アルミナ水和物に対して２％）、ポリビニルアルコール（ＰＶＡ−２３５、クラレ株式会社製）１．７部を水１５．３部に溶解したものを加えて塗工液を調製した。次にレジンコート紙（王子製紙（株）製）を基材とし、この基材上に先程調製した塗工液を乾燥塗布量３０ｇ／ｍ^２となるようにバーコート法にて塗工し、１００℃で３０分間熱風乾燥してインク受容層を形成させた。次にベンゾトリアゾール（関東化学社製）をエタノールに溶解し、これを先に作製したインク受容層上に、アルミナ水和物に対して固形分換算で２．０％添加となるように、オーバーコートし、１００℃、５分間熱風乾燥して被記録媒体を作製した。このようにして得られた被記録媒体を用いて前記評価を行った。
【０１１９】
＜実施例２＞
実施例１においてＮ，Ｎ’−ジエチルチオ尿素の添加量を０．８５部（アルミナ水和物に対して５％）、スミレーズレジン１００１（住友化学株式会社製）の添加量を固形分換算で０．１７部（アルミナ水和物に対して１％）、ベンゾトリアゾール（関東化学社製）の添加量をアルミナ水和物に対して固形分換算で０．５％となるようにした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１２０】
＜実施例３＞
実施例１においてＮ，Ｎ’−ジエチルチオ尿素の添加量を２．０４部（アルミナ水和物に対して１２％）、３％ホウ酸水溶液の量を固形分換算で０．１７部（アルミナ水和物に対して１％）とした以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１２１】
＜実施例４＞
実施例１においてベンゾトリアゾール（関東化学社製）の代わりにＫＥＭＩＳＯＲＢ７３（ケミプロ化成）をアルミナ水和物に対して固形分換算で２％添加した以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１２２】
＜比較例１＞
実施例１においてベンゾトリアゾール（関東化学社製）を添加しなかった以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
＜比較例２＞
実施例１においてＮ，Ｎ’−ジエチルチオ尿素を添加しなかった以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
【０１２３】
＜比較例３＞
実施例１においてホウ酸を添加しなかった以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
＜比較例４＞
実施例１においてスミレーズレジン１００１（住友化学株式会社製）を添加しなかった以外は実施例１と同様にして被記録媒体を作製し、前記評価を行った。
以上の実施例および比較例の評価結果を下記表２−３に示す。
【０１２４】

【０１２５】
以上の実施例および比較例から明らかなように、前記一般式（１）〜（４）で表される化合物、ホウ素化合物、アクリルアミド−ジアリルアミン塩酸塩共重合体およびベンゾトリアゾール系化合物をインク受容層に含有させた本発明の被記録媒体は、室内における画像堅牢性を左右する主たる原因と考えられる大気中の窒素酸化物、硫黄酸化物、オゾンによる画像の退色および変色が効果的に抑えられていた。また、光などによる画像の退色や保存した場合の白地部分の黄変、さらには高温高湿環境下における印字後の染料のマイグレーションが防止され、記録画像の長期保存性に優れたものであった。
【０１２６】
【発明の効果】
インク受容層に無機微粒子と前記一般式（１）〜（４）で表される少なくとも１種の化合物とアクリルアミド−ジアリルアミン塩酸塩共重合体とホウ素化合物を特定の比率で含有させる（第一発明）こと、無機微粒子の形状を特定する（第二発明）こと、さらには該インク受容層にベンゾトリアゾール系化合物を含有させる（第三発明）ことで、印字品位に優れ、長期保存における光や大気中の酸化物による画像の退色および変色と白地部分の黄変および染料インクのマイグレーションが抑制された被記録媒体を提供することができた。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording medium suitable for recording with ink, particularly when applied to a printer or plotter using an ink jet recording method, has excellent printing characteristics, fading of images in long-term storage, discoloration, dye after printing. The present invention relates to a recording medium in which migration is suppressed and yellowing of a white background is suppressed.
[0002]
[Prior art]
The ink jet recording method is a recording method for recording an image, a character, or the like by flying fine droplets of ink according to various operating principles and attaching the droplets to a recording medium such as paper. In addition, the ink jet recording system is characterized in that it has excellent high-speed printing properties, low noise, and flexibility in recording patterns, can easily perform multicolor printing, and does not require development and image fixing. In particular, an image formed by the multi-color ink jet method can obtain a record comparable to multi-color printing by a plate making method or printing by a color photographic method. In recent years, it has been rapidly popularized as an image recording device for various information devices, because it has an advantage that printing cost is lower than printing technology and photographic technology. For example, it is being widely applied to fields that require full-color image recording, such as the output of image design in the design industry, the production of color printing plates in the printing field where photographic quality is required, and signs and product samples that are frequently replaced. is there.
[0003]
In such an ink jet recording method, recording apparatuses and recording methods have been improved in order to improve recording characteristics such as high-speed recording, high definition, and full-color recording. Advanced characteristics have been required. In other words, the characteristics required for the recording medium include high density of print dots, vivid and bright color tone, high contrast, and high ink absorption such that ink does not flow out or bleed even when print dots overlap. That the ink has a printing dot shape close to a perfect circle without unnecessarily increasing the lateral diffusion of the ink, and that the periphery of the dot is smooth and not blurred.
[0004]
Several proposals have hitherto been made for these requirements. For example, Patent Literature 1 discloses a general paper type recording medium in which a low-size base paper is thinly coated with a paint for surface processing to increase ink absorbency. Patent Documents 2 to 4 disclose, in order to improve the reproducibility of the dot shape, density or color tone, which has been a drawback of the general paper type, from a silicon-containing inorganic pigment such as silica and a water-based binder on a substrate. A coating type recording medium to which a coating liquid is applied is disclosed. Furthermore, in order to obtain a surface gloss comparable to that of silver halide photographs, it was attempted to cast the ink receiving layer or to use a water-absorbing polymer for the ink receiving layer, but the former provided sufficient gloss. On the other hand, the latter has a drawback that the ink absorption rate is lower than that of the ink receiving layer made of an inorganic pigment such as silica.
[0005]
Therefore, a recording medium in which fine alumina hydrate is coated on a support together with a water-soluble binder has been proposed as one having improved ink absorbency, glossiness and transparency. For example, Patent Document 5 discloses a recording paper having a coating layer containing a porous cationic alumina hydrate. Patent Documents 6 to 12 disclose recording sheets containing alumina hydrate having a pseudo-boehmite structure. In particular, Patent Documents 9 and 13 disclose recording sheets containing alumina sol having a pseudo-boehmite structure and boric acid or borate. However, in a recording medium containing such inorganic fine particles, an image recorded by light or ozone may be discolored, or a white background of an unprinted portion may be colored yellow depending on specific conditions.
[0006]
In order to avoid such a problem, a recording medium containing various antioxidants, ultraviolet absorbers, light stabilizers, and the like has been proposed. For example, Patent Documents 14 to 16 disclose recording media containing a phenolic antioxidant, a benzophenone-based or benzotriazole-based ultraviolet absorber.
[0007]
Patent Document 17 discloses a medium containing a hindered amine compound, Patent Document 18 discloses a recording medium containing a hydrazide compound, Patent Document 19 describes an andecane compound, and Patent Document 20 describes a recording medium containing a thioether compound. Discloses a recording medium containing a chain-type polyvalent carboxylic acid, and Patent Document 22 proposes a recording medium containing an organic acid having an aromatic nucleus.
[0008]
Patent Documents 23 and 24 disclose recording media containing a thiourea derivative, a thiosemicarbazide derivative, a thiocarbohydrazide derivative, or the like. Further, in Patent Document 25, one kind from a thiourea derivative, a thiosemicarbazide derivative, and a thiocarbohydrazide derivative, and one kind from iodine, iodide, dithiocarbamic acid, thiocyanate, and thiocyanate are respectively contained. A recording medium is disclosed. However, such conventional means are impractical at present, for example, when exposed to a high-temperature and high-humidity environment, dye migration occurs and an image blurs. Furthermore, when a phenolic antioxidant is used, it oxidizes itself and is colored yellow, and there is also a problem that a white background portion turns yellow.
[0009]
As a method of preventing migration of a dye after printing, many methods are disclosed in which a sizing agent such as a cationic polymer having a tertiary or quaternary ammonium salt, an alkyl ketene dimer, or an alkenyl succinic anhydride is added to an ink receiving layer. However, when the antioxidants, light stabilizers, and ultraviolet absorbers described above are used in combination with a cationic polymer or a sizing agent, the effect of preventing migration is lost, and the effect of discoloration of an image is not only lost, but rather. In some cases, it worsens, and there are many adverse effects. Therefore, it has been difficult to simultaneously prevent the migration of the dye and the fading or discoloration of the image.
[0010]
[Patent Document 1]
JP-A-52-53012
[Patent Document 2]
JP-A-55-51583
[Patent Document 3]
JP-A-59-230787
[Patent Document 4]
JP-A-64-11877
[Patent Document 5]
JP-A-60-232990
[Patent Document 6]
JP-A-2-276670
[Patent Document 7]
JP-A-6-48016
[Patent Document 8]
JP-A-6-55829
[Patent Document 9]
JP-A-7-76161
[Patent Document 10]
JP-A-8-22608
[Patent Document 11]
JP-A-10-44585
[Patent Document 12]
JP-A-11-34484
[Patent Document 13]
JP 2000-239578 A
[Patent Document 14]
JP-A-57-74192
[Patent Document 15]
JP-A-57-87989
[Patent Document 16]
JP-A-60-72785
[Patent Document 17]
JP-A-61-146591
[Patent Document 18]
JP-A-61-154989
[Patent Document 19]
JP-A-1-18684
[Patent Document 20]
JP-A-1-115677
[Patent Document 21]
JP-A-6-286297
[Patent Document 22]
JP-A-6-316145
[Patent Document 23]
Japanese Patent Publication No. 4-34953
[Patent Document 24]
JP-A-7-314883
[Patent Document 25]
JP-A-8-25796
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described circumstances, has a high image density, exhibits a good color tone and ink absorbency, and suppresses fading and discoloration of an image during long-term storage, and simultaneously performs migration of a dye ink. It is an object of the present invention to provide a recording medium which has been improved and further suppressed yellowing of a white background.
[0012]
[Means for Solving the Problems]
The present inventors have conducted various studies in order to obtain a recording medium having excellent print quality and suppressed image fading, discoloration and dye migration during long-term storage. As a result, inorganic fine particles and a water-soluble resin and / or water In a recording medium having an ink receiving layer containing a dispersible resin as a main component, a compound represented by the following general formula (1), a compound represented by the following general formula (2), A compound represented by the general formula (3) and at least one compound represented by the following general formula (4) (hereinafter, referred to as "at least one compound represented by the general formulas (1) to (4)") ), An acrylamide-diallylamine hydrochloride copolymer and a boron compound, the inventors have found that the aforementioned problems can be solved, and have completed the present invention.
[0013]
That is, the first invention of the present invention provides at least one ink receiving layer on at least one surface of a base material, wherein the receiving layer comprises a water-soluble resin and / or a water-dispersible resin as a binder, and inorganic fine particles ( A), at least one compound represented by formulas (1) to (4) (B), an acrylamide-diallylamine hydrochloride copolymer (C), and a boron compound (D), The mass ratio of the above (A), (B), (C) and (D) is
4 × (B + C + D) ≦ A (1) and
(B / D): C = 0.1: 5 to 15: 0.1 (2)
A recording medium characterized by the following is provided.
[0014]

(Wherein X and Y may be the same or different and each independently represents a COOH group or an OH group. ¹ And R ² May be the same or different and represent an alkylene group or an arylene group. n represents an integer of 1 or 2. )
[0015]

(Where R ¹ ~ R ⁴ May be the same or different and represent a hydrogen atom, an alkyl group or an aryl group. Also, R ¹ And R ² Any one of and R ³ And R ⁴ May form a ring. n represents an integer of 1, 2 or 4. )
[0016]

(Where R ¹ ~ R ⁴ May be the same or different and represent a hydrogen atom, an alkyl group, an aryl group, or -NR ⁵ R ⁶ R represents a group represented by ⁵ And R ⁶ Is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group or -NR ⁷ CSNR ⁸ R ⁹ (Where R is ⁷ ~ R ⁹ Represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a phenyl group, which may be the same or different). Also, R ¹ And R ² Any one of and R ³ And R ⁴ May form a ring. )
[0017]

(Where R ¹ Represents an arylene group; ² Represents an alkyl group, an aryl group, a benzyl group, or a cyclohexyl group; ¹ Or R ² May have a substituent. )
[0018]
In the present invention, as a second invention, at least one ink receiving layer is provided on at least one surface of the base material, and the receiving layer comprises a water-soluble resin and / or a water-dispersible resin as a binder, and inorganic fine particles. And a compound represented by the general formula (4), a boron compound, an acrylamide-diallylamine hydrochloride copolymer, and a sulfur compound, and are measured by a dynamic light scattering method of the inorganic fine particles. Average particle size (d) and polydispersity index (μ / <Γ>) ² ) Satisfies the following formulas (3) and (4).
150 nm ≦ d ≦ 250 nm (3)
0.01 ≦ μ / <Γ> ² ≦ 0.20 ··· Equation (4)
[0019]
In the second invention, the sulfur compound is preferably at least one compound selected from the compounds represented by the general formulas (1) to (3).
[0020]
The present invention also provides, as a third invention, the recording medium of the first and second inventions, wherein the ink receiving layer further contains a benzotriazole-based compound.
[0021]
The recording medium of the first to third inventions having the ink receiving layer is excellent in printing characteristics such as image density and color tone, ink absorbency, and has little image fading, discoloration and dye migration during long-term storage, and has a white background. This is a recording medium in which yellowing of a portion is also suppressed.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments. First, basic materials common to the first to third inventions will be described.
As the base material used in the present invention, for example, those composed of papers such as films, cast-coated paper, baryta paper, resin-coated paper (resin-coated paper coated on both sides with a resin such as polyolefin) are preferably used. You. Examples of the film include transparent thermoplastic resin films such as polyethylene, polypropylene, polyester, polylactic acid, polystyrene, polyacetate, polyvinyl chloride, cellulose acetate, polyethylene terephthalate, polymethyl methacrylate, and polycarbonate.
[0023]
In addition, other sheet-like materials (such as synthetic paper) made of a suitably sized paper, unsized paper, coated paper, and a film opaque by filling with an inorganic substance or fine foaming: furthermore, glass or A sheet made of metal or the like may be used. In order to improve the adhesive strength between the substrate and the ink receiving layer, the surface of the substrate may be subjected to a corona discharge treatment or various undercoat treatments.
[0024]
The inorganic fine particles (A) used in the present invention are preferably inorganic fine particles having a high ink absorbing ability, excellent color developing properties, and capable of forming a high-quality image. As such inorganic fine particles, for example, calcium carbonate, magnesium carbonate, kaolin, clay, talc, hydrotalcite, aluminum silicate, calcium silicate, magnesium silicate, diatomaceous earth, alumina, colloidal alumina, aluminum hydroxide, boehmite structure Alumina hydrate and alumina hydrate having a pseudo-boehmite structure, synthetic amorphous silica, colloidal silica, lithopone, zeolite and the like can be mentioned, and these can be used alone or in combination of plural kinds. Among these inorganic fine particles, inorganic fine particles selected from aluminum hydroxide, alumina and at least one of alumina hydrates having a boehmite structure or a pseudo-boehmite structure are preferable, and alumina hydrates having a boehmite structure or a pseudo-boehmite structure are further preferable. Preferably used.
[0025]
In the compound represented by the general formula (1), R ¹ And R ² And X and Y are as defined above, and R ¹ And R ² Is preferably an alkylene group, one having 1 to 5 carbon atoms is preferable, and when it is an arylene group, a phenylene group or a naphthylene group is preferable. Any of these alkylene groups or arylene groups may have a substituent or may be unsubstituted. Also, R ¹ And R ² May be the same or different.
[0026]
Examples of the compound represented by the general formula (1) include the following.

[0027]
In the compound represented by the general formula (2), R ¹ ~ R ⁴ Is as defined above, and R ¹ ~ R ⁴ Is preferably an alkyl group having 1 to 10 carbon atoms, and an aryl group is preferably a phenyl group or a naphthyl group. Any of these alkyl groups or aryl groups may have a substituent or may be unsubstituted. Also, R ¹ And R ² May be the same or different.
[0028]
Examples of the compound represented by the general formula (2) include the following.

[0029]
In the compound represented by the general formula (3), R ¹ ~ R ⁹ Is as defined above, and R ¹ ~ R ⁴ Is preferably an alkyl group having 1 to 10 carbon atoms, and an aryl group is preferably a phenyl group or a naphthyl group. Any of these alkyl groups and aryl groups may be unsubstituted or may have a substituent.
[0030]
Specific examples of the compound represented by the general formula (3) include the following. First, R ¹ ~ R ⁴ Examples of compounds in which is a hydrogen atom, an alkyl group or an aryl group include the following.

[0031]
In the general formula (3), R ¹ ~ R ⁴ At least one of -NR ⁵ R ⁶ As the compound which is a group represented by, for example, the following compounds may be mentioned.

[0032]
Further, in the compound represented by the general formula (3), R ¹ And R ² Any one of and R ³ And R ⁴ Examples of the compound forming a ring with either one of the following include the following.

[0033]
In the compound represented by the general formula (4), R ¹ And R ² Is as defined above, and R ¹ The arylene group is preferably a phenylene group. Also, R ² Is preferably an alkyl group having 1 to 10 carbon atoms, and an aryl group is preferably a phenyl group or a naphthyl group. R ¹ And R ² Any of the alkyl groups or aryl groups of the above may have a substituent.
[0034]
Examples of the compound represented by the general formula (4) include the following.

[0035]
The amount of the at least one compound represented by the general formulas (1) to (4) is determined from the viewpoint of the ink absorption of the ink receiving layer and the effect of preventing discoloration and discoloration of an image formed thereon. The range is preferably from 0.5 to 15 parts by mass per 100 parts by mass of the inorganic fine particles, and within this range, the occurrence of ink bleeding and beading during printing can be more effectively prevented.
[0036]
In the present invention, a boron compound is used together with at least one compound represented by the general formulas (1) to (4). The boron compound used in the present invention is an oxygen acid or a salt thereof centered on a boron atom such as boric acid or borate, and specifically, for example, orthoboric acid, metaboric acid, hypoboric acid , Tetraboric acid, pentaboric acid and salts thereof.
[0037]
Generally, boric acid is used as a hardening agent for improving the film forming property, water resistance and film strength of a film formed by a hydrophilic polymer. As the hardener, various ones are selected depending on the type of the reactive group of the polymer to be used. For example, in the case of a polyvinyl alcohol-based resin, an epoxy hardener, boric acid, or a water-soluble aluminum salt is used. Inorganic hardeners such as are used.
[0038]
However, the role of the boron compound in the present invention is that the boron compound has an effect of preventing fading of images and discoloration, particularly when the boron compound is contained in the recording medium together with at least one compound represented by any of the general formulas (1) to (4). It is different from the use limited to the action as a hardener in increasing the prevention effect.
[0039]
The amount of the boron compound (D) used in the present invention is 0.5 to 5 parts by mass per 100 parts by mass of the inorganic fine particles in order to achieve both a synergistic effect for preventing fading and discoloration of the image and good coating stability. It is preferable to use a part. More preferably, the mixing mass ratio of at least one compound (B) represented by the general formulas (1) to (4) and the boron compound (D) is 1 to 5 parts by mass per 100 parts by mass of the inorganic fine particles.
0.1 ≦ B / D ≦ 15 Expression (5)
Is preferably within the range. When the ratio of the amounts of the at least one compound represented by the general formulas (1) to (4) and the boron compound, that is, B / D is less than 0.1, the compound is formed on the base material. The ink receiving layer may be cracked or a synergistic effect of the effect of preventing discoloration and discoloration of an image cannot be expected. When B / D exceeds 15, the coating liquid may gel or the coating stability may deteriorate.
[0040]
The acrylamide-diallylamine hydrochloride copolymer used in the present invention is a copolymer containing acrylamide represented by the following general formula (5) and diallylamine hydrochloride as constituent components. In the formula, the molar fraction (m) of diallylamine is generally in the range of 0.01 to 0.99, preferably 0.15 to 0.95, and the molar fraction (n) of acrylamide is , Generally in the range of 0.99 to 0.01, preferably in the range of 0.85 to 0.05. If the molar fraction of diallylamine is less than 0.01, the effect of preventing water resistance and migration of the image after inkjet recording is not sufficiently exhibited, so that it is not practical to extremely reduce the amount of diallylamine.

[0041]
The monomer sequence in the polymer chain of the above copolymer may have any structure such as a random copolymer, an alternating copolymer, a block copolymer, and a multi-block copolymer. Although the molecular weight and molecular weight distribution are not particularly limited, it can be said that the molecular weight is preferably 5,000 to 200,000 in consideration of the viscosity of an aqueous solution.
[0042]
The acrylamide-diallylamine hydrochloride copolymer is generally used as a dye fixing agent for the purpose of improving the water resistance of an image formed on a recording medium. Such a dye fixing agent forms a salt with an inkjet dye having an anionic group and is insolubilized in water to improve the water resistance of an image.
[0043]
However, the purpose of using the acrylamide-diallylamine hydrochloride copolymer in the present invention is not only to impart the function of water resistance of an image and the function of preventing migration of a dye, but also to the formulas (1) to (4). The use of at least one compound and the boron compound at the same time further improves the effect of preventing discoloration and discoloration of an image.
[0044]
Hereinafter, features of the first invention of the present invention will be described. This first invention is characterized by the mixing ratio of the materials used for forming the ink receiving layer. The amounts of the at least one compound (B) represented by the general formulas (1) to (4), the boron compound (D) and the acrylamide-diallylamine hydrochloride copolymer (C) used in the first invention are as follows. , In the range of the following equation (2).
(B / D): C = 0.1: 5 to 15: 0.1 (2)
The ratio of the amount of the at least one compound represented by the general formulas (1) to (4) and the amount of the boron compound used, that is, the ratio of (B / D) to the acrylamide-diallylamine hydrochloride copolymer is as described above. In the range, the effect of preventing discoloration and fading of an image is further improved, and at the same time, the effect of preventing migration of a dye is also obtained.
[0045]
The amount of the boron compound or the acrylamide-diallylamine hydrochloride copolymer varies greatly depending on the amount of the inorganic fine particles (A) and the water-soluble resin and / or the water-dispersible resin used as the binder. The mixing mass ratio of at least one compound (B) represented by (4), acrylamide-diallylamine hydrochloride copolymer (C) and the boron compound (D), that is, (B / D): C = 0 In the range of 1: 5 to 15: 0.1 (Equation 2), 4 × (B + C + D) ≦ A (Equation 1), that is, the total amount of B, C and D is 25 parts by mass per 100 parts by mass of the inorganic fine particles. It is preferred to add them in a proportion of not more than parts by weight. Preferably, (B + C + D) is in the range of 1.55 to 25 parts by mass per 100 parts by mass of the inorganic fine particles. When the content of (B + C + D) exceeds 25 parts by mass, the viscosity of the coating liquid for forming the ink receiving layer changes with time, and the coating stability may be poor. When (B + C + D) is less than 1.55 parts by mass, the effect of preventing discoloration and fading of an image and the effect of suppressing migration, which are objects of the present invention, may not be sufficient.
[0046]
Further, in the first invention, the inorganic fine particles have an average particle diameter of 150 to 250 nm and a polydispersity index (μ / <Γ>). ² ) Is preferably in the range of 0.01 to 0.20, more preferably the average particle diameter of the inorganic fine particles is in the range of 160 to 230 nm, and the polydispersity index is in the range of 0.01 to 0.18. . By using such inorganic fine particles, in addition to the effects of the first invention, the effects of the second invention described below can be simultaneously obtained.
[0047]
Hereinafter, features of the second invention of the present invention will be described. In this second invention, the ink receiving layer contains the compound of the general formula (4) and a sulfur compound, and is characterized in the form of inorganic fine particles. That is, in the second invention, as the form of the inorganic fine particles (A), in order to obtain a highly glossy and highly transparent ink receiving layer, the average particle diameter is 150 to 250 nm and the polydispersity index (μ / <Γ). > ² ) Is in the range of 0.01 to 0.20. More preferably, the average particle diameter of the inorganic fine particles is in the range of 160 to 230 nm, and the polydispersity index is in the range of 0.01 to 0.18. When the average particle diameter of the inorganic fine particles is smaller than 150 nm, the ink absorption of the ink receiving layer is reduced, and bleeding or beading occurs when printing with a printer that discharges a large amount of ink or a printer that outputs at high speed. There is a risk. On the other hand, when the average particle diameter is larger than 250 nm, the transparency of the ink receiving layer is reduced, and the gas resistance may be reduced. Also, when the polydispersity index exceeds 0.20, the transparency, print density and gloss of the ink receiving layer are reduced as in the case of the average particle diameter, and the image after printing may be dull.
In the second invention, it is preferable to use at least one compound selected from the compounds represented by the general formulas (1) to (3) as the sulfur compound.
[0048]
The average particle diameter and the polydispersity index referred to in the second invention are measured by a dynamic light scattering method, and are described in “Structural Experiment of Polymer (2) Scattering Experiment and Morphological Observation Chapter 1 Light Scattering” (edited by Kyoritsu Shuppan Polymer Society) ) Or J. Chem. Phys. , 70 (B), 15 ApI. , 3965 (1979). In the dynamic light scattering method, when fine particles having different particle sizes are mixed, the distribution of the time correlation function from the scattered light has a distribution. By analyzing the time correlation function using the cumulant method, the average (<Γ>) and the variance (μ) of the decay rates are obtained. Since the decay rate (Γ) is represented by a function of the particle diffusion coefficient and the scattering vector, the hydrodynamic mean particle diameter can be determined using the Stokes-Einstein equation. Therefore, the variance (μ) of the decay rate is calculated as the mean square (<（> ² ) Divided by the polydispersity index (μ / <Γ>) ² ) Represents the degree of dispersion of the particle diameter, and means that the distribution of the particle diameter becomes narrower as the value approaches 0. The average particle size and polydispersity index defined in the present invention can be easily measured using, for example, a laser particle size analyzer PARIII (manufactured by Otsuka Electronics Co., Ltd.).
[0049]
Hereinafter, the third invention of the present invention will be described. The third invention is characterized in that the ink receiving layer of the recording medium according to the first invention and the second invention further contains a benzotriazole compound. Specific examples of the benzotriazole-based compound used in the third invention include, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole (Sumisorb 200: Sumitomo Chemical), 2- [2-Hydroxy-3- (3,4) , 5,6-tetrahydrophthalamide-methyl) -5-methylphenyl] benzotriazole (Sumisorb 250: Sumitomo Chemical), 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzoyl benzoylazole (5-chlorobenzol) 2- (2-Hydroxy-5-tert-octylphenyl) benzotriazole (Sumisorb 40: Sumitomo Chemical), Benzotriazole (Kanto Chemical), 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (KEMISORB73: Chemipro Kasei), 2- [2-hydroxy- 3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole (TINUVIN234: Ciba Specialty Chemical), 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzo Commercially available products such as triazole (TINUVIN 320: Ciba specialty chemical) and hydroxyphenylbenzotriazole derivative (TINUVIN 571: Ciba specialty chemical) are exemplified. The benzotriazole-based compound used in the present invention is not limited to these, and may be used alone or as a mixture of two or more.
[0050]
The amount of the benzotriazole-based compound to be used is preferably 0.05 to 3 parts by mass per 100 parts by mass of the inorganic pigment, and within this range, it is represented by the aforementioned general formulas (1) to (4). Even when at least one compound and a boron compound and an acrylamide-diallylamine hydrochloride copolymer coexist, the light fastness of an image and the effect of preventing yellowing of a white background portion are not impaired.
[0051]
Hereinafter, other common matters of the first to third inventions will be described. In the present invention, the mixing mass ratio of the above components satisfies the formulas (1) and (2), and the following range is preferable as a whole.
・ Inorganic fine particles ・ ・ ・ 100 parts by mass
-Water-soluble resin and / or water-dispersible resin: 3.33 to 100 parts by mass
At least one compound represented by the general formulas (1) to (4): 0.5 to 15 parts by mass
Acrylamide-diallylamine hydrochloride copolymer: 0.05 to 5 parts by mass
-Boron compound: 1 to 5 parts by mass
・ Benzotriazole compound: 0.05 to 3 parts by mass
[0052]
The recording medium of the present invention can be obtained by preparing a coating liquid containing the above components and applying the coating liquid to the surface of a substrate to form an ink receiving layer. The layer preferably has voids formed from the inorganic fine particles and a small amount of a water-soluble resin and / or a water-dispersible resin. From the viewpoint that finer voids can be formed, it is preferable to use aluminum hydroxide, alumina, alumina hydrate having a boehmite structure or pseudo-boehmite structure as the inorganic fine particles. In particular, the BET specific surface area is 50 m ² / G or more of alumina hydrate having alumina, boehmite structure or pseudo-boehmite structure is preferred.
As the alumina hydrate used in the present invention, those represented by the following general formula (6) can be used.
Al ₂ O _3-n (OH) _2n ・ MH ₂ O: General formula (6)
In the formula, n represents any one of the integers 0, 1, 2, and 3, and m represents a value of 0 to 10, preferably 0 to 5. mH ₂ Since O often represents a detachable aqueous phase that does not contribute to the formation of a crystal lattice, m can take a non-integer value. Also, when this type of alumina hydrate is calcined, m can reach a value of 0.
[0053]
In general, the crystal of alumina hydrate having a boehmite structure is a layered compound whose (020) plane forms a giant plane, and shows a unique diffraction peak in an X-ray diffraction pattern. As the boehmite structure, a structure containing excess water between layers on the (020) plane, which is called pseudo-boehmite, in addition to complete boehmite, may be employed. The X-ray diffraction pattern of this pseudo-boehmite shows a broader diffraction peak than perfect boehmite. Since complete boehmite and pseudo-boehmite cannot be clearly distinguished, hereinafter, unless otherwise specified, they are referred to as alumina hydrate showing a boehmite structure including both.
[0054]
The method for producing the alumina hydrate having a boehmite structure contained in the recording medium according to the present invention is not particularly limited, as long as the method can produce an alumina hydrate having a boehmite structure. It can also be produced by a known method such as hydrolysis or hydrolysis of sodium aluminate.
[0055]
As disclosed in JP-A-56-120508, an amorphous alumina hydrate which is X-ray diffractive is used in the form of a boehmite structure by heat treatment at 50 ° C. or more in the presence of water. be able to. A method that can be particularly preferably used is a method in which an acid is added to a long-chain aluminum alkoxide to carry out hydrolysis and peptization to obtain an alumina hydrate.
[0056]
Here, the long-chain aluminum alkoxide is, for example, an alkoxide having 5 or more carbon atoms. When an alkoxide having 12 to 22 carbon atoms is used, the removal of alcohol and the shape of alumina hydrate will be described later. It is preferable because control becomes easy.
[0057]
As the acid to be added, one or more kinds of organic acids and inorganic acids can be freely selected and used. The reaction efficiency of hydrolysis and the shape control and dispersibility of the obtained alumina hydrate can be used. In view of this, nitric acid is most preferred. After this step, it is also possible to control the particle size by performing hydrothermal synthesis or the like. When hydrothermal synthesis is performed using an alumina hydrate dispersion containing nitric acid, nitric acid in the aqueous solution is incorporated as a nitrate group on the surface of the alumina hydrate to improve water dispersibility.
[0058]
The above method has an advantage that impurities such as various ions are less likely to be mixed as compared with a method for producing alumina hydrogel or cationic alumina. Further, since the long-chain aluminum alkoxide easily removes the alcohol after hydrolysis, it is possible to completely remove the alcohol from the alumina hydrate in comparison with the case where a short-chain alkoxide such as aluminum isopropoxide is used. There is an advantage that you can.
[0059]
Further, the dispersion liquid of the inorganic fine particles synthesized by the above method can be further adjusted to a desired particle size by physical means using a pulverizer / disperser or the like. As the pulverizer / disperser that can be used in the present invention, various known dispersers can be used. A stirring type disperser, an ultrasonic disperser and the like can be mentioned.
[0060]
Specifically, a Menton Gorin homogenizer, a sonolator (manufactured by Doei Shoji), a microfluidizer (manufactured by Mizuho Industries), a nanomizer (manufactured by Tsukishima Kikai), an optimizer (manufactured by ITOCHU), a pearl mill, a grain mill, a tornado (Made by Asada Iron & Steel Co., Ltd.), Visco Mill (made by Imex Co., Ltd.), Mighty Mill, RS Mill, SΓ Mill (made by Inoue Seisakusho), Ebara Milder (made by Ebara Seisakusho), Fine Flow Mill, Cavitron (made by Daiheiyo Kiko Co., Ltd.), etc. No.
[0061]
The recording medium of the present invention includes the inorganic fine particles (A), at least one compound (B) represented by the general formulas (1) to (4), an acrylamide-diallylamine hydrochloride copolymer (C), A composition comprising a boron compound is mixed with a necessary amount of a water-soluble resin and an aqueous medium to prepare a coating liquid, which is applied to the surface of a substrate and dried to form an ink receiving layer. Is obtained.
[0062]
As the configuration of the recording medium of the present invention, such as a coated paper and a coated film, provided with an ink receiving layer on a substrate, a part or most of the coating liquid is impregnated near the surface of the substrate The ink receiving layer can be selected from those having an ink receiving layer formed thereon, or a configuration in which an ink receiving layer is formed by applying a small amount of a coating liquid onto a substrate surface. In the present invention, these configurations are also included as “the ink receiving layer is formed on the surface of the substrate”.
[0063]
Examples of the water-soluble resin to be contained in the coating liquid include aqueous or water-dispersible polymer compounds, for example, starch, gelatin, casein and modified products thereof, methylcellulose, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, Completely or partially saponified polyvinyl alcohol or a modified product thereof (cation-modified, anion-modified, silanol-modified, etc.), urea resin, melamine resin, epoxy resin, epichlorohydrin resin, polyurethane resin, polyethyleneimine resin, polyamide Resin, polyvinyl pyrrolidone resin, polyvinyl butyral resin, poly (meth) acrylic acid or its copolymer, acrylamide resin, maleic anhydride copolymer, polyester resin, SBR latex, NBR Tex, methyl methacrylate-butadiene copolymer latex, acrylic polymer latex such as acrylate copolymer, vinyl polymer latex such as ethylene-vinyl acetate copolymer, and cationic latex Alternatively, functional group-modified polymer latexes having an anionic group may be used.
[0064]
Particularly preferred is polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate and having an average degree of polymerization of 300 to 5,000. The saponification degree is preferably from 70 to less than 100%, particularly preferably from 80 to 99.5%. These water-soluble or water-dispersible resins can be used alone or as a mixture of two or more.
[0065]
The mixing mass ratio of the inorganic fine particles and the water-soluble resin in the coating liquid is preferably in the range of 1: 1 to 30: 1, more preferably in the range of 3: 1 to 20: 1. When the amount of the water-soluble resin is within these ranges, the formed ink receiving layer is less likely to crack or fall off, and has good ink absorbency.
[0066]
The aqueous medium of the coating solution is not particularly limited as long as it is a mixed solution with water or an organic solvent that can be mixed with water. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol and propanol: lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether: ketones such as acetone and methyl ethyl ketone: tetrahydrofuran Ethers.
[0067]
The solid content concentration in the coating liquid for forming the ink receiving layer is not particularly limited as long as the viscosity is such that the ink receiving layer can be formed on the substrate, but is 5 to 5% based on the total mass of the coating liquid. 50% by mass is preferred. When the solid content concentration is less than 5% by mass, it is necessary to increase the coating amount to increase the thickness of the ink receiving layer, and it becomes uneconomical because much time and energy are required for drying. There are cases. On the other hand, if it exceeds 50% by mass, the viscosity of the coating liquid may increase, and the coating properties may be reduced.
[0068]
Various additives can be added to the coating liquid within a range that does not impair the effects of the present invention. Such additives include surfactants, pigment dispersants, thickeners, defoamers, ink fixers, dot conditioners, colorants, fluorescent brighteners, antioxidants, ultraviolet absorbers, preservatives And a pH adjuster.
[0069]
As a method of applying the prepared coating liquid on the substrate, any known coating method can be applied, for example, a blade coating method, an air knife coating method, a curtain coating method, a slot die coating method, a bar coating method Depending on the coating method such as gravure coating method and roll coating method, the dry coating amount is 0.5 to 60 g / m ² It is applied so that After that, the ink receiving layer can be formed by drying using a drying device such as a hot air dryer, a heat drum, or a far infrared dryer. The ink receiving layer may be formed by changing the composition ratio of the inorganic fine particles to the resin and other additives, or may be formed on one side or both sides of the substrate. Further, for the purpose of improving the resolution and transportability of an image, a smoothing process may be performed using a device such as a super calendar or a soft calendar.
[0070]
A preferable range of the coating amount of the coating liquid on the substrate is 0.5 to 60 g / m in terms of solid content. ² And a more preferred range is 5 to 55 g / m. ² It is. 0.5 g / m coating amount ² If it is less than 60 g / m2, the formed ink receiving layer may not sufficiently absorb the water of the ink, and the ink may flow or the image may bleed. ² If it exceeds 2,000, curling may occur during drying, or a remarkable effect may not be exhibited as expected in printing performance.
[0071]
Although it is not clear why the recording medium of the present invention has excellent print quality as described above, and particularly has an excellent inhibitory effect on fading and discoloration of an image during long-term storage, it is probably unclear that the general formulas (1) to ( It is considered that at least one kind of compound represented by 4), an acrylamide-diallylamine hydrochloride copolymer, and a boron compound caused some interaction, and such an effect was exhibited.
[0072]
The ink used when recording on the recording medium of the present invention is not particularly limited, but a dye or a pigment is used as a coloring material, and a mixture of water and a water-soluble organic solvent is used as a medium. It is preferable to use a general aqueous ink for inkjet recording in which a dye or pigment is dissolved or dispersed.
[0073]
As a method for forming an image by applying the ink to the recording medium, an ink jet recording method is particularly preferable. As the ink jet recording method, the ink is effectively separated from the nozzles to form the ink on the recording medium. Any method can be used as long as the method can provide the. In particular, according to the method described in Japanese Patent Application Laid-Open No. 54-59936, the ink subjected to the action of thermal energy causes a sudden volume change, and the ink is ejected from the nozzle by the action force due to this state change. Can be used effectively.
[0074]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples. In the following examples, “parts” and “%” are based on mass unless otherwise specified.
<Production of alumina hydrate>
Aluminum dodexide was prepared by the method described in U.S. Pat. No. 4,242,271. Next, the aluminum dodoxide was hydrolyzed by the method described in U.S. Pat. No. 4,202,870 to produce an alumina slurry. Water was added to the alumina slurry until the alumina hydrate having a boehmite structure had a solid content of 7.7%. The pH of the alumina slurry was 9.4. The pH was adjusted by adding a 3.9% nitric acid solution.
[0075]
Next, using an autoclave, aging was performed at pH before aging: 6.0, aging temperature: 150 ° C, and aging time: 6 hours to obtain a colloidal sol. The colloidal sol was spray-dried at an inlet temperature of 87 ° C. to obtain an alumina hydrate powder. The obtained powder was an alumina hydrate having a flat particle shape and a boehmite crystal structure. Furthermore, the alumina hydrate having a boehmite structure was added to a concentration of 19% in ion-exchanged water and mixed to prepare an alumina hydrate dispersion.
[0076]
The dispersion obtained by the above method was redispersed under several conditions using an ultrasonic homogenizer MUS-600CCVP-12 (manufactured by Nippon Seiki Seisaku-sho, Ltd.), and coarse particles were removed by centrifugation. Was added to prepare 17% alumina hydrate dispersions A to E. The centrifugation operation was not performed on the alumina hydrate dispersion liquid F. The average particle diameter (nm) and polydispersity index (μ / <Γ>) of the alumina hydrate dispersion thus obtained are described. ² ) Was measured using a laser particle size analyzer PARIII (manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Table 1 below.
[0077]

[0078]
<Evaluation 1: Evaluation method for fading / discoloration suppression effect>
The discoloration and discoloration due to exposure to ozone can be determined by using an inkjet recording device (BJ F900, manufactured by Canon Inc.) to convert the yellow (Y), magenta (M), cyan (C), and black (Bk) inks into a single color ink. A recording medium solid-printed at an amount of 100% was placed in an ozone exposure tester (manufactured by Suga Test Instruments Co., Ltd., special order product), exposed to ozone at a concentration of 3 ppm at 40 ° C. and 55% RH for 2 hours, and stored. Before and after, the color change of the printed portion was visually evaluated. When there was no difference in color between each color, it was evaluated as ○, when there was a slight difference in color between any of the colors, and Δ when there was a large difference between any of the colors.
[0079]
<Evaluation 2: Evaluation method for migration prevention effect>
Using a inkjet recording apparatus (BJ F900, manufactured by Canon Inc.), a recording medium on which Y, M, C, and Bk inks are printed in a single color and with a solid ink amount of 100% in an environment of 30 ° C. and 80% RH. When stored for one week, the degree of migration of the dye before and after storage was visually evaluated. In each color, no migration occurred. In each color, a slight migration occurred, and in each color, the degree of migration was evaluated as x.
[0080]
<Evaluation 3: Method for evaluating ink absorbency>
Solid printing from single color to four colors was performed using an ink jet recording apparatus (BJ F900, manufactured by Canon Inc.). The dried state of the ink on the surface of the recording medium after printing was touched to the recording portion with a finger to check the ink absorbency. The amount of ink in single-color solid printing was set to 100%. When the ink amount is 300% (mixed three colors) and the ink does not adhere to the finger, ◎: When the ink amount is 200% (mixed two colors), the ink does not adhere to the finger: ○. A sample that did not perform was evaluated as Δ, and a sample that 100% of the ink adhered to the finger was evaluated as x.
[0081]
<Evaluation 4: Evaluation method for yellowing of a white background portion: Evaluation was performed only in the third invention. >
For the purpose of evaluating the degree of yellowing of the white portion of the recording medium, 1% dissolution of BHT dimer (4,4'-methylenebis-2,6-di-t-butylphenol) in ethanol, which is considered as one of the causes. The liquid is added to the recording medium in a solid content of 0.5 g / m ² The mixture was allowed to dry naturally, and allowed to stand at 20 ° C. and 65% RH for 24 hours, and then visually evaluated for coloring.着色 indicates that almost no coloring was observed, Δ indicates that the color was slightly yellow, and X indicates that the color was extremely yellow.
[0082]
"First invention"
<Example 1>
100 parts (solid content: 17 parts) of the alumina hydrate dispersion B and 0.82 parts (4.8% based on alumina hydrate) of β-thiodiglycol and a 3% boric acid aqueous solution were solidified. 0.68 part in terms of minute (4% based on alumina hydrate) and 0.17 part in terms of solids of Sumireze Resin 1001 (manufactured by Sumitomo Chemical Co., Ltd.) as an acrylamide-diallylamine hydrochloride copolymer (1% based on alumina hydrate) and a solution prepared by dissolving 1.7 parts of polyvinyl alcohol (PVA-224, manufactured by Kuraray) in 15.3 parts of water are prepared. did. Next, a resin-coated paper was used as a base material, and the coating solution prepared above was dried on the base material at a dry coating amount of 35 g / m 2. ² Was applied by a bar coating method and dried with hot air at 100 ° C. for 30 minutes to form an ink receiving layer. The recording medium thus obtained was subjected to solid printing of from one color to four colors using an ink jet recording apparatus (BJ F900, manufactured by Canon Inc.), and the above evaluations 1 to 3 were performed.
[0083]
<Example 2>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion C, and the amount of boric acid added was 0.34 parts (2% based on the alumina hydrate) in terms of solid content and Sumireze A recording medium was prepared in the same manner as in Example 1 except that the addition amount of the resin 1001 was 0.085 parts (0.5% based on alumina hydrate) in terms of solid content, and the above evaluation was performed. .
[0084]
<Example 3>
100 parts of the alumina hydrate dispersion D (17 parts of solid content), 0.17 parts of a 3% boric acid aqueous solution in terms of solid content (1% based on alumina hydrate), and acrylamide-diallylamine hydrochloride As a salt copolymer, Sumirezu Resin 1001 (manufactured by Sumitomo Chemical Co., Ltd.) to which 0.017 parts (0.1% based on alumina hydrate) was added in terms of solid content, and polyvinyl alcohol (PVA- 224 (manufactured by Kuraray Co., Ltd.) was dissolved in 15.3 parts of water to prepare a coating liquid. Next, a resin-coated paper was used as a base material, and the coating solution prepared above was dried on the base material at a dry coating amount of 35 g / m 2. ² Was applied by a bar coating method and dried with hot air at 100 ° C. for 30 minutes to form an ink receiving layer. Next, a solution prepared by dissolving 1 part of tetramethylthiuram monosulfide in 40 parts of methanol was overcoated on the ink receiving layer prepared previously so that 8.2% of alumina hydrate was added thereto. A recording medium was prepared and the above evaluation was performed.
[0085]
<Example 4>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion E, and the amount of β-thiodiglycol added was 2.55 parts (15% based on alumina hydrate). The addition amount of the acid was 0.17 parts in terms of solids (1% based on alumina hydrate), and the addition amount of Sumireze resin 1001 was 0.51 parts in terms of solids (3% based on alumina hydrate). %), A recording medium was prepared in the same manner as in Example 1, and the evaluation was performed.
[0086]
<Example 5>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion C, and instead of β-thiodiglycol, 1.21 parts of 3,3′-thiodipropionic acid was added (to the alumina hydrate). The amount of boric acid added was 0.17 parts in terms of solids (1% based on alumina hydrate), and the amount of Sumireze resin 1001 was 0.34 parts in terms of solids. (2% based on alumina hydrate) A recording medium was prepared in the same manner as in Example 1 except that the evaluation was performed.
[0087]
<Example 6>
In Example 1, alumina hydrate dispersion B was replaced with alumina hydrate dispersion C, and instead of β-thiodiglycol, 2.55 parts of 2,2′-thiodiglycolic acid was added (to alumina hydrate). The amount of boric acid added was 0.85 parts in terms of solids (5% based on alumina hydrate), and the amount of Sumireze resin 1001 was 0.51 parts in terms of solids (alumina). A recording medium was prepared in the same manner as in Example 1 except that the hydrate was 3%), and the evaluation was performed.
[0088]
<Example 7>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion C, and instead of β-thiodiglycol, 0.34 parts of N, N′-diethylthiourea was added (based on the alumina hydrate). 2%), the amount of boric acid added was 0.34 parts in terms of solids (2% based on alumina hydrate), and the amount of Sumireze resin 1001 was 0.085 parts in terms of solids (alumina hydrate). A recording medium was prepared in the same manner as in Example 1 except that the content was set to 0.5% based on the product, and the above evaluation was performed.
[0089]
Example 8
In Example 1, alumina hydrate dispersion B was replaced with alumina hydrate dispersion C, and instead of β-thiodiglycol, 0.17 parts of thiourea (1% based on alumina hydrate) was used instead of β-thiodiglycol. The amount of the acid added was 0.17 parts in terms of solids (1% based on alumina hydrate) and the amount of Sumireze resin 1001 was 0.017 parts in terms of solids (0% based on alumina hydrate). 0.1%), a recording medium was produced in the same manner as in Example 1, and the evaluation was performed.
[0090]
<Example 9>
A recording medium was prepared in the same manner as in Example 7 except that the alumina hydrate dispersion liquid C was changed to the alumina hydrate dispersion liquid F in Example 7, and the above evaluation was performed.
<Example 10>
A recording medium was produced in the same manner as in Example 7 except that the alumina hydrate dispersion C was changed to the alumina hydrate dispersion A in Example 7, and the above evaluation was performed.
[0091]
<Comparative Example 1>
A recording medium was prepared in the same manner as in Example 2 except that Sumire Resin 1001 was not added, and the evaluation was performed.
<Comparative Example 2>
A recording medium was prepared in the same manner as in Example 2 except that β-thiodiglycol was not added, and the evaluation was performed.
[0092]
<Comparative Example 3>
A recording medium was prepared in the same manner as in Example 2 except that β-thiodiglycol and Sumireze Resin 1001 were not added, and the evaluation was performed.
<Comparative Example 4>
In Example 2, in place of Sumireze resin 1001, PAA-HCl-3L (manufactured by Nitto Boseki Co., polyallylamine hydrochloride) was converted to a solid content of 0.085 parts (0.5% based on alumina hydrate). A recording medium was prepared in the same manner as in Example 2 except for adding, and the evaluation was performed.
[0093]
<Comparative Example 5>
In Example 2, instead of Sumireze Resin 1001, Sunfix 414 (a polyalkylene polyamine / dicyandiamide polycondensate manufactured by Sanyo Chemical Industries, Ltd.) was used in an amount of 0.085 parts (based on alumina hydrate) in terms of solid content. A recording medium was prepared in the same manner as in Example 2 except that the recording medium was added, and the above evaluation was performed.
[0094]
<Comparative Example 6>
A recording medium was prepared in the same manner as in Example 2 except that boric acid was not added, and the evaluation was performed.
<Comparative Example 7>
In Example 3, the addition amount of tetramethylthiuram monosulfide was 3.4 parts (20% based on alumina hydrate), and the addition amount of boric acid was 0.51 part (3% based on alumina hydrate). A recording medium was prepared in the same manner as in Example 3 except that the amount of Sumire Resin 1001 added was 0.51 part (3% based on alumina hydrate), and the above evaluation was performed.
[0095]
<Comparative Example 8>
In Example 2, the addition amount of β-thiodiglycol was 1.7 parts (10% based on alumina hydrate), and the addition amount of boric acid was 1.02 parts (6% based on alumina hydrate). ) And Sumire's Resin 1001 were added in an amount of 2.50 parts (14.7% based on alumina hydrate) to prepare a coating solution in the same manner as in Example 2. The recording medium could not be produced because the liquid gelled.
[0096]
<Comparative Example 9>
A coating liquid was prepared in the same manner as in Example 2 except that the addition amount of Sumireze Resin 1001 was 3.00 parts (17.6% based on alumina hydrate) in Example 2. The recording medium could not be produced because the coating liquid was gelled.
Table 2-1 below shows the evaluation results of the above Examples and Comparative Examples.
[0097]

[0098]
As is clear from the above Examples and Comparative Examples, the binder, the inorganic fine particles, at least one compound represented by the general formulas (1) to (4), the acrylamide-diallylamine hydrochloride copolymer and the boron compound were used. When an image is recorded on a recording medium that is simultaneously contained in the ink receiving layer at a specific mixing ratio, nitrogen oxides and sulfur oxides in the air are considered to be the main causes that affect the robustness of images in a room. It was possible to effectively prevent discoloration and fading of the image due to ozone and the like and migration of the dye after printing in a high-temperature and high-humidity environment.
[0099]
"Second invention"
<Example 1>
A solution prepared by dissolving 5 parts of VIOSORB 90 (pt-butylphenyl salicylate, manufactured by Kyodo Yakuhin Co., Ltd.) in 95 parts of ethanol was applied to the surface of the ink receiving layer of the recording medium of Example 1 of the first invention by alumina hydration. A recording medium was produced by overcoating so that 3.0% was added to the recording medium. On the recording medium thus obtained, solid printing of from one color to four colors was performed using an ink jet recording apparatus (BJ F850, manufactured by Canon Inc.), and the above evaluation was performed.
[0100]
<Example 2>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion C, the amount of boric acid added was 0.34 parts (2.0% based on alumina hydrate), and Sumireze resin was used. Except that the addition amount of 1001 was 0.085 parts (0.5% based on alumina hydrate), and the addition amount of VIOSORB90 for overcoating the ink receiving layer was 3% based on alumina hydrate. A recording medium was prepared in the same manner as in Example 1, and the evaluation was performed.
[0101]
<Example 3>
On the surface of the ink receiving layer of the recording medium of Example 3 of the first invention, a solution obtained by dissolving 5 parts of VIOSORB 90 (pt-butylphenyl salicylate, manufactured by Kyodo Yakuhin Co., Ltd.) in 95 parts of ethanol was further added to the ink receiving layer. A recording medium was prepared by overcoating the layer so that 1.0% was added to alumina hydrate, and the above evaluation was performed.
[0102]
<Example 4>
In Example 1, the alumina hydrate dispersion B was replaced with the alumina hydrate dispersion E, and the amount of β-thiodiglycol added was 2.55 parts (15% based on alumina hydrate). 0.17 parts (1% based on alumina hydrate), 0.51 parts (3% based on alumina hydrate) of Sumireze Resin 1001, and overcoated the ink receiving layer. A recording medium was prepared in the same manner as in Example 1 except that the amount of VIOSORB 90 to be added was 4.8% with respect to alumina hydrate, and the evaluation was performed.
[0103]
<Example 5>
In Example 2, 1.23 parts of 3,3'-thiodipropionic acid (7.1% based on alumina hydrate) was added instead of β-thiodiglycol, and the amount of boric acid added was 0%. .17 parts (1% based on alumina hydrate), 0.34 parts (2% based on alumina hydrate) of Sumireze resin 1001, and VIOSORB 90 added overcoating the ink receiving layer A recording medium was prepared in the same manner as in Example 2 except that the content was adjusted to 3.0% with respect to alumina hydrate, and the evaluation was performed.
[0104]
<Example 6>
In Example 2, 2.55 parts (15% based on alumina hydrate) of 2,2′-thiodiglycolic acid was added instead of β-thiodiglycol, and the amount of boric acid added was 0.85. Parts (5% based on alumina hydrate), 0.51 parts (3% based on alumina hydrate) of Sumireze Resin 1001, and VIOSORB 90 added overcoating the ink receiving layer with alumina. A recording medium was prepared in the same manner as in Example 2 except that the content was adjusted to 3.0% with respect to the hydrate, and the evaluation was performed.
[0105]
<Example 7>
In Example 2, 0.34 parts (2% based on alumina hydrate) of 1,3-diethyl-2-thiourea was added instead of β-thiodiglycol, and the amount of boric acid added was 0.34. Parts (2% based on alumina hydrate), 0.085 parts (0.5% based on alumina hydrate) of Sumirezu Resin 1001, and the amount of VIOSORB 90 to overcoat the ink receiving layer A recording medium was prepared in the same manner as in Example 2 except that the content was adjusted to 3.0% with respect to alumina hydrate, and the evaluation was performed.
[0106]
Example 8
In Example 2, 0.17 parts (1% based on alumina hydrate) of thiourea was added instead of β-thiodiglycol, and the amount of boric acid added was 0.17 parts (based on alumina hydrate). 1%), the amount of Sumireze resin 1001 added was 0.017 parts (0.1% based on alumina hydrate), and the amount of VIOSORB90 overcoated on the ink receiving layer was based on alumina hydrate. A recording medium was produced in the same manner as in Example 2 except that the content was 3.0%, and the evaluation was performed.
[0107]
<Comparative Example 1>
Example 7 Example 7 was repeated except that Sumireze resin 1001 was not added and the amount of 1,3-diethyl-2-thiourea was changed to 0.82 parts (4.8% based on alumina hydrate). A recording medium was prepared in the same manner as in No. 7, and the evaluation was performed.
[0108]
<Comparative Example 2>
In Comparative Example 1, 0.085 parts of Sumireze resin 1001 (0.5% based on alumina hydrate) was added, and SEESORB100 (a benzophenone-based ultraviolet absorber; manufactured by Cypro Chemical Co., Ltd.) was used instead of VIOSORB90. A recording medium was prepared in the same manner as in Comparative Example 1 except that the solution dissolved in ethanol was added in an amount of 3% in terms of solid content with respect to alumina hydrate, and the above evaluation was performed.
[0109]
<Comparative Example 3>
In Comparative Example 2, a solution prepared by dissolving ADK STAB L77 (hindered amine-based light stabilizer, manufactured by Asahi Denka Kogyo KK) in 5 parts of ethanol instead of VIOSORB 90 was added in an amount of 3% with respect to alumina hydrate in terms of solid content. A recording medium was prepared in the same manner as in Comparative Example 2 except that overcoating was performed as described above, and the evaluation was performed.
[0110]
<Comparative Example 4>
To 100 parts (a solid content of 17 parts) of the alumina hydrate dispersion C, 0.83 parts (4.8% based on alumina hydrate) of 1,3′-diethyl-2-thiourea, and Needal U-15 (Cerium oxide solid content concentration 15%; manufactured by Taki Kagaku Co., Ltd.) 0.51 part in terms of solid content (3% based on alumina hydrate), and 3% boric acid aqueous solution in terms of solid content 0.34. Parts (2% based on alumina hydrate) and 0.085 parts (0.5% based on alumina hydrate) of Sumireze Resin 1001 in terms of solid content, and polyvinyl alcohol (PVA- 235 (manufactured by Kuraray Co., Ltd.) in a solution of 1.7 parts in 15.3 parts of water to prepare a coating solution. Next, a resin-coated paper was used as a base material, and the coating solution prepared above was coated on the base material with a dry coating amount of 40 g / m 2. ² Was applied by a bar coating method and dried with hot air at 100 ° C. for 30 minutes to form an ink receiving layer, thereby producing a recording medium. However, the evaluation was not performed because the recording medium was colored yellow.
[0111]
<Comparative Example 5>
Comparative Example 2 was the same as Comparative Example 2 except that boric acid was not added, and a solution obtained by dissolving VIOSORB 90 in 5 parts of ethanol instead of SEESORB 100 was overcoated so that 3% of alumina hydrate was added in terms of solid content. A recording medium was prepared in the same manner as in Example 2, and the above evaluation was performed.
[0112]
<Comparative Example 6>
In Comparative Example 2, a solution prepared by dissolving VIOSORB 90 in 5 parts of ethanol instead of SEESORB 100 without adding 1,3′-diethyl-2-thiourea was added in an amount of 3% with respect to alumina hydrate in terms of solid content. A recording medium was prepared in the same manner as in Comparative Example 2 except that overcoating was performed as described above, and the evaluation was performed.
[0113]
<Comparative Example 7>
In Comparative Example 2, a recording medium was produced in the same manner as in Comparative Example 2 except that SEESORB 100 was not added, and the evaluation was performed.
[0114]
<Comparative Example 8>
In Comparative Example 7, an alumina hydrate dispersion liquid F was used in place of the alumina hydrate dispersion liquid C, and a solution obtained by dissolving VIOSB 90 in 5 parts of ethanol was added to the alumina hydrate at a solid content of 3%. A recording medium was prepared in the same manner as in Comparative Example 7 except that overcoating was performed as described above, and the evaluation was performed.
[0115]
<Comparative Example 9>
In Comparative Example 7, an alumina hydrate dispersion A was used in place of the alumina hydrate dispersion C, and a solution obtained by dissolving VIOSORB 90 in 5 parts of ethanol was added to the alumina hydrate at a solid content of 3%. A recording medium was prepared in the same manner as in Comparative Example 7 except that overcoating was performed as described above, and the evaluation was performed.
Table 2-2 below shows the evaluation results of the above Examples and Comparative Examples.
[0116]

[0117]
As is clear from the above Examples and Comparative Examples, inorganic fine particles having a specific average particle size and polydispersity index, the compound represented by the general formula (4), the boron compound, the acrylamide-diallylamine hydrochloride copolymer, and sulfur When an image is recorded on a recording medium containing the compound in the ink receiving layer at the same time, nitrogen oxides in the atmosphere, sulfur oxides, ozone, etc., which are considered to be the main factors that determine the robustness of the image in the room It was possible to effectively prevent discoloration and fading of the image and discoloration due to light. In particular, when the compound represented by the general formula (4) is contained in the ink receiving layer, a recording medium with further improved gas resistance is produced as compared with the case where the sulfur compound is used alone. I was able to.
[0118]
"Third invention"
<Example 1>
To 100 parts of the alumina hydrate dispersion liquid C (17 parts of solid content), 0.51 part of N, N'-diethylthiourea (3% with respect to alumina hydrate), and a 3% boric acid aqueous solution in terms of solid content were used. 0.34 part (2% based on alumina hydrate) and 0.34 part (alumina hydrate) of Sumireze Resin 1001 (manufactured by Sumitomo Chemical Co., Ltd.) as an acrylamide-diallylamine hydrochloride copolymer in terms of solid content 2%) and 1.7 parts of polyvinyl alcohol (PVA-235, manufactured by Kuraray Co., Ltd.) dissolved in 15.3 parts of water were added to prepare a coating liquid. Next, a resin-coated paper (manufactured by Oji Paper Co., Ltd.) was used as a base material, and the coating solution prepared above was coated on the base material with a dry coating amount of 30 g / m 2. ² Was applied by a bar coating method and dried with hot air at 100 ° C. for 30 minutes to form an ink receiving layer. Next, benzotriazole (manufactured by Kanto Chemical Co., Ltd.) is dissolved in ethanol, and this is added onto the previously prepared ink receiving layer so that 2.0% is added to alumina hydrate in terms of solid content. It was coated and dried with hot air at 100 ° C. for 5 minutes to produce a recording medium. The above evaluation was performed using the recording medium thus obtained.
[0119]
<Example 2>
In Example 1, the addition amount of N, N'-diethylthiourea was 0.85 parts (5% based on alumina hydrate), and the addition amount of Sumireze Resin 1001 (manufactured by Sumitomo Chemical Co., Ltd.) was calculated as solid content. 0.17 parts (1% based on alumina hydrate), except that the amount of benzotriazole (manufactured by Kanto Kagaku) was 0.5% in terms of solids based on alumina hydrate. A recording medium was prepared in the same manner as in Example 1, and the evaluation was performed.
[0120]
<Example 3>
In Example 1, the addition amount of N, N'-diethylthiourea was 2.04 parts (12% based on alumina hydrate), and the amount of 3% boric acid aqueous solution was 0.17 parts in terms of solid content (alumina water). A recording medium was prepared in the same manner as in Example 1 except that the content was set to 1% with respect to the sum, and the above evaluation was performed.
[0121]
<Example 4>
A recording medium was produced in the same manner as in Example 1 except that KEMISORB 73 (Chempro Kasei) was added to alumina hydrate at 2% in terms of solid content instead of benzotriazole (manufactured by Kanto Chemical Co., Ltd.). Then, the above evaluation was performed.
[0122]
<Comparative Example 1>
A recording medium was prepared in the same manner as in Example 1 except that benzotriazole (manufactured by Kanto Chemical Co., Ltd.) was not added, and the evaluation was performed.
<Comparative Example 2>
A recording medium was prepared in the same manner as in Example 1 except that N, N'-diethylthiourea was not added, and the evaluation was performed.
[0123]
<Comparative Example 3>
A recording medium was prepared in the same manner as in Example 1 except that boric acid was not added, and the evaluation was performed.
<Comparative Example 4>
A recording medium was prepared in the same manner as in Example 1 except that Sumirezu Resin 1001 (manufactured by Sumitomo Chemical Co., Ltd.) was not added, and the evaluation was performed.
Table 2-3 below shows the evaluation results of the above Examples and Comparative Examples.
[0124]

[0125]
As is clear from the above Examples and Comparative Examples, the compounds represented by the general formulas (1) to (4), the boron compound, the acrylamide-diallylamine hydrochloride copolymer and the benzotriazole-based compound are used in the ink receiving layer. In the recording medium of the present invention, the fading and discoloration of the image due to nitrogen oxides, sulfur oxides, and ozone in the air, which are considered to be the main causes affecting the image fastness in a room, were effectively suppressed. . Further, discoloration of the image due to light or yellowing of a white background portion when preserved, and migration of a dye after printing in a high-temperature and high-humidity environment were prevented, and the recorded image was excellent in long-term preservability. .
[0126]
【The invention's effect】
The ink receiving layer contains inorganic fine particles, at least one compound represented by the above general formulas (1) to (4), an acrylamide-diallylamine hydrochloride copolymer and a boron compound in a specific ratio (first invention). By specifying the shape of the inorganic fine particles (second invention), and further including a benzotriazole-based compound in the ink receiving layer (third invention), the printing quality is excellent and the light and air in long-term storage are excellent. It was possible to provide a recording medium in which the discoloration and discoloration of the image due to the oxide, the yellowing of the white background portion, and the migration of the dye ink were suppressed.

Claims (13)

At least one ink-receiving layer is provided on at least one surface of the substrate, and the ink-receiving layer comprises a water-soluble resin and / or a water-dispersible resin as a binder, inorganic fine particles (A), and a compound represented by the following general formula (1): , At least one compound (B) represented by the general formulas (2), (3) and (4), an acrylamide-diallylamine hydrochloride copolymer (C), and a boron compound (D) And the mass ratio of the above (A), (B), (C) and (D) is 4 × (B + C + D) ≦ A (1), and (B / D): C = 0.1: 5 to 15: 0.1 ··· Equation (2)
A recording medium characterized by the following.

(In the formula, X and Y may be the same or different and each independently represents a COOH group or an OH group. R ¹ and R ² may be the same or different and represent an alkylene group or an arylene group. n represents an integer of 1 or 2.)

(Wherein, R ^{1 to} R ⁴ may be the same or different and represent a hydrogen atom, an alkyl group, or an aryl group. In addition, any one of R ¹ and R ² and any one of R ³ and R ⁴ One of them may form a ring, and n represents an integer of 1, 2 or 4.)

(Wherein, R ^{1 to} R ⁴ may be the same or different and represent a hydrogen atom, an alkyl group, an aryl group or a group represented by —NR ⁵ R ⁶ , wherein R ⁵ and R ⁶ are a hydrogen atom, An alkyl group having 1 to 5 carbon atoms, a phenyl group or a group represented by —NR ⁷ CSNR ⁸ R ⁹ (where R ^{7 to} R ⁹ are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a phenyl group, Which may be the same or different), and either one of R ¹ and R ² and one of R ³ and R ⁴ may form a ring.)

(In the formula, R ¹ represents an arylene group, R ² represents an alkyl group, an aryl group, a benzyl group, or a cyclohexyl group, and R ¹ or R ² may have a substituent.) At least one ink receiving layer is provided on at least one surface of the substrate, and the receiving layer comprises a water-soluble resin and / or a water-dispersible resin as a binder, inorganic fine particles, and the general formula (1) according to claim 1. Average particle diameter (d) containing the compound represented by 4), a boron compound, an acrylamide-diallylamine hydrochloride copolymer, and a sulfur compound, and measured by dynamic light scattering of the inorganic fine particles. And a polydispersity index (μ / <Γ> ² ) satisfying the following expressions (3) and (4).
150 nm ≦ d ≦ 250 nm (3)
0.01 ≦ μ / <Γ> ² ≦ 0.20 Equation (4) 3. The coating according to claim 2, wherein the sulfur compound is at least one compound selected from the compounds represented by the general formulas (1), (2) and (3). recoding media. The recording medium according to claim 1, wherein the ink receiving layer further contains a benzotriazole-based compound. The recording medium according to claim 4, wherein the content of the benzotriazole-based compound is 0.05 to 3 parts by mass per 100 parts by mass of the inorganic fine particles. The recording medium according to claim 1, wherein the base material is a resin-coated paper. The recording medium according to claim 1, wherein the binder is a polyvinyl alcohol having an average degree of polymerization of 300 to 5,000 and a degree of saponification of less than 70 to 100% obtained by hydrolyzing polyvinyl acetate. 3. The recording medium according to claim 1, wherein the inorganic fine particles are at least one of aluminum hydroxide, alumina, and alumina hydrate having a boehmite structure or a pseudo-boehmite structure. The recording medium according to claim 1, wherein the inorganic fine particles are alumina hydrate having a boehmite structure or a pseudo-boehmite structure manufactured from an aluminum alkoxide having 12 to 22 carbon atoms. The recording medium according to claim 1, wherein the acrylamide-diallylamine hydrochloride copolymer is a copolymer represented by the following general formula (5).

(The mole fraction m in the formula is 0.01 to 0.99, and the mole fraction n is 0.99 to 0.01.) The recording medium according to claim 10, wherein the molar fraction m is in a range of 0.15 to 0.95, and the molar fraction n is in a range of 0.85 to 0.05. 3. The recording medium according to claim 1, wherein the boron compound contained in the ink receiving layer is boric acid or borate. The ink receiving layer is composed of 100 parts by mass of inorganic fine particles, 3.33 to 100 parts by mass of a water-soluble resin and / or a water-dispersible resin, and at least one compound 0 represented by the general formulas (1) to (4). 3. The recording medium according to claim 1, comprising 0.5 to 15 parts by mass, 0.05 to 5 parts by mass of an acrylamide-diallylamine hydrochloride copolymer, and 1 to 5 parts by mass of a boron compound.