JP2004291264A - Recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosensitive/pressure sensitive recording material which forms an image with a feel of depth by enhancing the sharpness (resolution) and brightness (feeling of glitter) of a support and has ameliorated texture light resistance. <P>SOLUTION: In the recording material with a recording layer which can develop a color by applying heat and/or pressure, formed on the support, at least one layer containing a polyvinyl alcohol, a bismuth oxychloride and a hardener is formed on the recording layer side of the support. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３２】
下塗り層における上記ハメットの置換基定数σ_ｐ値が正である置換基に隣接するビニル基を単一分子内に二つ以上有する化合物の含有量は、アセトアセチル変性ＰＶＡ等のＰＶＡ１００部に対して、０．１〜３０部の範囲であることが好ましく、０．５〜１０部の範囲であることがより好ましい。
【００３３】
−層状無機化合物−
上記下塗り層には、さらに層状無機化合物を添加することができる。該層状無機化合物としては、膨潤性無機層状化合物が好ましく、例えば、ベントナイト、ヘクトライト、サポナイト、ビーデライト、ノントロナイト、スチブンサイト、バイデライト、モンモリナイト等の膨潤性粘度鉱物類、膨潤性合成雲母、膨潤性合成スメクタイト等が挙げられる。これらの膨潤性無機層状化合物は１０〜１５オングストロームの厚みの単位結晶格子層からなる積層構造を有し、格子内金属原子置換が他の粘土鉱物よりも著しく大きい。その結果、格子層は正荷電不足を生じ、それを補償するために層間にＮａ^＋、Ｃａ^２＋、Ｍｇ^２＋等の陽イオンを吸着している。これらの層間に介在している陽イオンは交換性陽イオンと呼ばれ、いろいろな陽イオンと交換する。特に層間の陽イオンがＬｉ^＋、Ｎａ^＋等の場合、イオン半径が小さいため、層状結晶格子間の結合が弱く、水により大きく膨潤する。その状態でシェアーをかけると容易に劈開し、水中で安定したゾルを形成する。ベントナイト及び膨潤性合成雲母はその傾向が強く本発明の目的には好ましく、特に水膨潤性雲母が好ましい。
【００３４】
水膨潤性雲母としては、ＮａテトラシックマイカＮａＭｇ_２．５（Ｓｉ_４Ｏ_１０）Ｆ_２Ｎａ、Ｌｉテニオライト（ＮａＬｉ）Ｍｇ_２（Ｓｉ_４Ｏ_１０）Ｆ_２Ｎａ、またはＬｉヘクトライト（ＮａＬｉ）／３Ｍｇ_２／３Ｌｉ_１／３Ｓｉ_４Ｏ_１０）Ｆ_２等が挙げられる。
【００３５】
本発明において好ましく用いられる水膨潤性雲母のサイズは、厚みが１〜５０ｎｍの範囲、面サイズが１〜２０μｍの範囲である。拡散制御のためには、厚みは薄ければ薄いほどよく、平面サイズは塗布面の平滑性及び透明性を悪化させない範囲で大きいほどよい。従って、アスペクト比は１００以上であることが好ましく、２００以上であることがより好ましく、５００以上であることがさらに好ましい。
【００３６】
下塗り層に含有されるＰＶＡの質量（ｘ１）と水膨潤性雲母の質量（ｙ１）との質量比率（ｘ１／ｙ１）は、２〜１０の範囲であることが好ましく、５〜１０の範囲であることがより好ましい。上記質量比率が２〜１０の範囲であると、酸素透過抑制に効果が大きい。また、上記ＰＶＡの塗布量は、１ｍ^２当たり０．５ｇ以上であることが好ましく、０．８ｇ以上であることがより好ましい。上記塗布量を１ｍ^２当たり０．５ｇ以上とすることにより、十分なガス透過抑制効果を発揮させることができる。また、上記塗布量の上限としては、１ｍ^２当たり２．０ｇ以下であることが好ましく、１．５ｇ以下であることがより好ましい。上記塗布量が１ｍ^２当たり２．０ｇ以下とすることにより、記録材料の感度及びＤｍａｘ（べた画像濃度）を十分に確保することができる。また、上記水膨潤性雲母の塗布量は、酸素透過抑制として０．２０ｇ／ｍ^２以上であることが好ましく、前記ＰＶＡの塗布量と上記ＰＶＡとの質量比率とから導きだせるものが好ましい。
【００３７】
上記下塗り層は、前記ＰＶＡ、オキシ塩化ビスマス及び硬膜剤、さらに、必要に応じ層状無機化合物、その他の成分を溶解または分散してなる塗布液をブレード塗布法、スプレー塗布法等の公知の塗布法により支持体表面に塗布し、乾燥することにより形成することができる。なお、塗布液の固形分濃度は、均一な膜を形成する等の観点から、５〜２５質量％の範囲であることが好ましい。
【００３８】
下塗り層の膜厚は、０．５μｍ〜２．５μｍの範囲であることが好ましく、０．５μｍ〜２．０μｍの範囲であることがより好ましい。上記膜厚を０．５μｍ〜２．５μｍの範囲内とすることにより、ガス透過抑制効果及びＤｍａｘが十分で、かつ、塗膜の均一性を確保することができるため、高画質化に寄与できる。
【００３９】
（支持体）
本発明の記録材料に用いる支持体は、紙基材の両面を樹脂でコーティングしてなる層を有する。前記支持体に使用される紙基材としては、通常の天然パルプを主成分とする天然パルプ紙、天然パルプと合成繊維とから成る混抄紙、合成繊維を主成分とする合成繊維紙、ポリスチレン、ポリエチレンテレフタレート、ポリプロピレンなどの合成樹脂フィルムを擬紙化した、所謂合成紙の何れでもよいが、天然パルプ紙（以下、単に「原紙」又は「紙基体」ともいう。）が特に好ましく用いられる。原紙は中性紙（ｐＨ５〜９）でも酸性紙でもよいが、中性紙が好ましい。
【００４０】
前記原紙は、針葉樹、広葉樹等から選ばれる天然パルプを主原料に、必要に応じ、クレー、タルク、炭酸カルシウム、尿素樹脂微粒子等の填料、ロジン、アルキルケテンダイマー、高級脂肪酸、エポキシ化脂肪酸アミド、パラフィンワックス、アルケニルコハク酸等のサイズ剤、でんぷん、ポリアミドポリアミンエピクロルヒドリン、ポリアクリルアミド等の紙力増強剤、硫酸バンド、カチオン性ポリマー等の定着剤等を添加したものを用いることができる。また、界面活性剤等の柔軟剤を添加してもよい。さらに、紙支持体として、上記天然パルプに代えて合成パルプを使用した合成紙を使用してもよく、天然パルプと合成パルプとを任意の比率に混合したものを使用してもよい。中でも、短繊維で平滑性が高くなる広葉樹パルプを用いるのが好ましい。使用するパルプ材の水度は、２００〜５００ｍｌ（Ｃ．Ｓ．Ｆ）の範囲であることが好ましく、３００〜４００ｍｌの範囲であることがより好ましい。
【００４１】
上記紙基材は、その他の成分を含有していてもよい。その他の成分としては、サイズ剤、柔軟化剤、紙力剤、定着剤等が挙げられる。上記サイズ剤としては、ロジン、パラフインワックス、高級脂肪酸塩、アルケニルコハク酸塩、脂肪酸無水物、スチレン無水マレイン酸共重合物、アルキルケテンダイマー、エポキシ化脂肪酸アミド等が挙げられる。上記柔軟化剤としては、無水マレイン酸共重合物とポリアルキレンポリアミンとの反応物、高級脂肪酸の４級アンモニウム塩等が挙げられる。紙力剤としては、ポリアクリルアミド、スターチ、ポリビニルアルコール、メラミンホルムアルデヒド縮合物、ゼラチン等が挙げられる。上記定着剤としては、硫酸バンド、ポリアミドポリアミンエピクロルヒドリン等が挙げられる。その他、染料、螢光染料、帯電防止剤等を必要に応じて添加することができる。
【００４２】
前記表面にポリオレフィン樹脂層を有する支持体としては、原紙（紙基材）の両面をポリオレフィン樹脂でラミネートしてなる支持体が好ましい。樹脂層で紙基材を被覆する場合には、紙基材にコロナ放電処理、火炎処理、グロー放電処理、プラズマ処理等の活性化処理を施すことが好ましい。前記ポリオレフィン樹脂層は単層でも多層でもよい。また、多層の場合には、ポリオレフィン樹脂からなる層の組み合わせから構成される積層体でもよい。原紙の両面をポリオレフィンラミネートしてなる支持体を用いると、支持体の表面平滑性が向上し、画像濃度に起因して発生する画像部の厚みの高低差、いわゆるブリスターをさらに軽減できるので好ましい。上記ポリオレフィン樹脂の中ではポリエチレン、ポリプロピレンが好ましく、ポリエチレンがより好ましい。
【００４３】
本発明におけるポリオレフィン樹脂からなる層は、ポリオレフィン樹脂を溶融し、紙基体表面に、通常ラミネート法、逐次ラミネート法、またはフィートブロックタイプ、マルチマニホールドタイプ、マルチスロットタイプ等の単層あるいは多層押出用ダイによるラミネート法のいずれかの方法により積層して形成される。ダイの形状は特に制限されるものではないが、一般にＴダイ、コートハンガーダイ等が好ましく用いられる。
【００４４】
上記ラミネート法としては、例えば、加工技術研究会編「新ラミネート加工便覧」に記載されたような公知の方法から適宜選択して採用することができ、いわゆるドライラミネーション、無溶剤型ドライラミネーション、ホットメルトラミネーション等の方法を採用することができる。例えば、ドライラミネーションによって上記ポリオレフィン樹脂からなる層を形成する場合は、ポリオレフィン樹脂フィルムの片面に、接着剤を塗布して、所望により乾燥し、原紙の表面に熱圧着することによって、形成することができる。上記接着剤としては、溶剤型のビニル系樹脂、アクリル系樹脂、ポリアミド系樹脂、エポキシ系樹脂、ゴム系樹脂、ウレタン樹脂等が挙げられる。また、原紙の表面、及び／または、裏面にコロナ放電処理を施し、ポリオレフィン樹脂からなる層との密着性を向上させてもよい。
【００４５】
なお、紙基体とポリオレフィン樹脂層の密着力を改良するために、ロジン誘導体樹脂、テルペン樹脂（例えば、高分子β−ピネン）、クマロン・インデン樹脂及び石油系炭化水素樹脂等の中から適宜選択できる粘着付与剤樹脂をポリオレフィン樹脂に配合することができる。これらは単独で用いても２種以上を混合していてもよい。
【００４６】
上記石油系炭化水素樹脂の具体例としては、脂肪族系石油樹脂、芳香族系石油樹脂、ジシクロペンタジエン系石油樹脂、共重合系石油樹脂、水添系石油樹脂及び脂環族系石油樹脂等が挙げられる。脂肪族系石油樹脂は、特に炭素原子数５のものが好ましく、芳香族系石油樹脂は、特に炭素原子数９のものが好ましい。このような粘着付与剤樹脂の配合量はポリオレフィンに対し、０．５〜６０質量％の範囲であることが好ましく、１０〜３５質量％の範囲であることがより好ましい。粘着付与剤樹脂の配合量が０．５質量％未満となると、接着不良となり、６０重量％を超えると製造時に塗布幅方向の厚みムラが生じ、特に支持体の端部が厚くなり、製造時の効率に悪い影響を及ぼす。また、ポリオレフィンと熱融着可能な接着性樹脂をポリオレフィン中に配合してもよい。このような接着性樹脂としては、例えば、アイオノマー、エチレン−酢酸ビニル共重合体（ＥＶＡ）、エチレン−アクリル酸共重合体並びにこれらの金属塩等が挙げられる。この接着性樹脂の配合量は、ポリオレフィンに対して２０〜５００質量％の範囲であることが好ましく、５０〜２００質量％の範囲であることがより好ましい。なお、前記粘着付与剤樹脂と接着性樹脂とを併用してもよい。
【００４７】
（記録層）
本発明の記録材料は、熱、及び／または、圧力の供与によって発色可能な少なくとも一層以上の記録層を有する。多色画像形成用の記録材料とする場合は、熱、及び／または、圧力の供与によって相互に異なる色相に発色可能な記録層を２以上有する。特に、多色用の記録材料では、各々の記録層に供与するエネルギーに高低の差をもたせて、所望の色に発色させるため、高印字エネルギーの印画時にブリスターの発生が顕著となるが、本発明の記録材料は、前記下塗り層のガス（水蒸気）透過性抑制によってブリスターの発生を抑制することができ、多色画像の画質を良好に維持することができる。
【００４８】
本発明の記録材料としては、シアン、マゼンタ、イエローに各々発色する複数の記録層が形成された、フルカラー画像を形成し得る多色用の記録材料であることが好ましい。当該多色用の記録材料については、特開平１１−３４４９５号公報第３６欄〜第３８欄に記載の構成例及び記録方法を本発明の記録材料に適用することができる。
【００４９】
上記記録層は、常温・常圧状態では無色で、熱、及び／または、圧力の供与により発色反応する発色成分を含有することが好ましい。上記発色成分としては、下記（ａ）〜（ｒ）の組み合わせが挙げられる。
（ａ）電子供与性染料前駆体と電子受容性化合物との組合せ。
（ｂ）ジアゾ化合物とカップリング成分（以下、「カプラー化合物」という場合がある。）との組合せ。
（ｃ）ベヘン酸銀、ステアリン酸銀等の有機酸金属塩と、プロトカテキン酸、スピロインダン、ハイドロキノン等の還元剤との組合せ。
（ｄ）ステアリン酸第二鉄、ミリスチン酸第二鉄等の長鎖脂肪酸鉄塩と、タンニン酸、没食子酸、サリチル酸アンモニウム等のフェノール類との組合せ。
（ｅ）酢酸、ステアリン酸、パルミチン酸等のニッケル、コバルト、鉛、銅、鉄、水銀、銀塩のような有機酸重金属塩と、硫化カルシウム、硫化ストロンチウム、硫化カリウム等のアルカリ金属またはアルカリ土類金属硫化物との組合せ、または上記有機酸重金属塩と、ｓ−ジフェニルカルバジド、ジフェニルカルバゾン等の有機キレート剤との組合せ。
【００５０】
（ｆ）銀、鉛、水銀、ナトリウム等の硫酸塩等の重金属硫酸塩と、ナトリウムテトラチオネート、チオ硫酸ソーダ、チオ尿素等の硫黄化合物との組合せ。
（ｇ）ステアリン酸第二鉄等の脂肪族第二鉄塩と、３，４−ヒドロキシテトラフェニルメタン等の芳香族ポリヒドロキシ化合物との組合せ。
（ｈ）シュウ酸銀、シュウ酸水銀等の有機酸金属塩と、ポリヒドロキシアルコール、グリセリン、グリコール等の有機ポリヒドロキシ化合物との組合せ。
（ｉ）ペラルゴン酸第二鉄、ラウリン酸第二鉄等の脂肪酸第二鉄塩と、チオセシルカルバミドやイソチオセシルカルバミド誘導体との組合せ。
（ｊ）カプロン酸鉛、ペラルゴン酸鉛、ベヘン酸鉛等の有機酸鉛塩と、エチレンチオ尿素、Ｎ−ドデシルチオ尿素等のチオ尿素誘導体との組合せ。
【００５１】
（ｋ）ステアリン酸第二鉄、ステアリン酸銅等の高級脂肪族重金属塩とジアルキルジチオカルバミン酸亜鉛との組合せ。
（ｌ）レゾルシンとニトロソ化合物との組合せのようなオキサジン染料を形成するもの。
（ｍ）ホルマザン化合物と還元剤、及び／または、金属塩との組合せ。
（ｎ）保護された色素（またはロイコ色素）プレカーサと脱保護剤との組合せ。
（ｏ）酸化型発色剤と酸化剤との組合せ。
（ｐ）フタロニトリル類とジイミノイソインドリン類との組合せ（フタロシアニンが生成する組合せ）。
（ｑ）イソシアナート類とジイミノイソインドリン類との組合せ（着色顔料が生成する組合せ）。
（ｒ）顔料プレカーサーと酸または塩基との組合せ（顔料が形成する組合せ）。
【００５２】
上記発色成分としては、（ａ）電子供与性染料前駆体と電子受容性化合物との組合せ、及び（ｂ）ジアゾ化合物とカップリング成分との組合せが好ましい。
【００５３】
−電子供与性染料前駆体−
上記（ａ）の組み合わせに用いられる電子供与性染料前駆体としては、フタリド系化合物、フルオラン系化合物、フェノチアジン系化合物、インドリルフタリド系化合物、ロイコオーラミン系化合物、ローダミンラクタム系化合物、トリフェニルメタン系化合物、トリアゼン系化合物、スピロピラン系化合物、ピリジン系、ピラジン系化合物、フルオレン系化合物等の各種化合物を挙げることができる。
【００５４】
上記フタリド系化合物としては、例えば、米国再発行特許第２３，０２４号明細書、米国特許第３，４９１，１１１号明細書、同第３，４９１，１１２号明細書、同第３，４９１，１１６号明細書及び同第３，５０９，１７４号明細書に記載の化合物が挙げられ、具体的には、３，３−ビス（ｐ−ジメチルアミノフェニル）−６−ジメチルアミノフタリド、３，３−ビス（ｐ−ジメチルアミノフェニル）フタリド、３−（ｐ−ジメチルアミノフェニル）−３−（１，３−ジメチルインドール−３−イル）フタリド、３−（ｐ−ジメチルアミノフェニル）−３−（２−メチルインドール−３−イル）フタリド等が挙げられる。
【００５５】
上記フルオラン系化合物としては、例えば、米国特許第３，６２４，１０７号明細書、同第３，６２７，７８７号明細書、同第３，６４１，０１１号明細書、同第３，４６２，８２８号明細書、同第３，６８１，３９０号明細書、同第３，９２０，５１０号明細書、同第３９５９，５７１号明細書に記載の化合物が挙げられ、具体的には、２−（ジペンジルアミノ）フルオラン、２−アニリノ−３−メチル−６−ジエチルアミノフルオラン、２−アニリノ−３−メチル−６−ジブチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−エチル−Ｎ−イソアミルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−メチル−Ｎ−シクロヘキシルアミノフルオラン、２−アニリノ−３−クロル−６−ジエチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−エチル−Ｎ−イソプチルアミノフルオラン、２−アニリノ−６−ジブチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−メチル−Ｎ−テトラヒドロフルフリルアミノフルオラン、２−アニリノ−３−メチル−６−ビペリジノアミノフルオラン、２−（ｏ−クロロアニリノ）−６−ジエチルアミノフルオラン、２−（３，４−ジクロルアニリノ）−６−ジエチルアミノフルオラン等が挙げられる。
【００５６】
上記チアジン系化合物としては、例えば、ベンゾイルロイコンメチレンブルー、ｐ−ニトロベンジルロイコメチレンブルー等が挙げられる。
【００５７】
上記ロイコオーラミン系化合物としては、例えば、４，４’−ビス−ジメチルアミノベンズヒドリンベンジルエーテル、Ｎ−ハロフェニル−ロイコオーラミン、Ｎ−２，４，５−トリクロロフェニルロイコオーラミン等が挙げられる。
【００５８】
上記ローダミンラクタム系化合物としては、ローダミン−Ｂ−アニリノラクタム、ローダミン−（ｐ−ニトロ）ラクタム等が挙げられる。
【００５９】
上記スピロピラン系化合物としては、例えば、米国特許第３，９７１，８０８号明細書に記載の化合物が挙げられ、具体的には、３−メチル−スピロ−ジナフトピラン、３−エチル−スピロ−ジナフトピラン３，３’−ジクロロ−スピロ−ジナフトピラン、３−ベンジルスピロ−ジナフトピラン、３−メチル−ナフト−（３−メトキシ−ベンゾ）スピロピラン、３−プロピル−スピロ−ジベンゾピラン等が挙げられる。
【００６０】
上記ピリジン系、及び上記ピラジン系化合物類としては、例えば、米国特許第３，７７５，４２４号明細書、同第３，８５３，８６９号明細書、同第４，２４６，３１８号明細書に記載の化合物が挙げられる。
【００６１】
上記フルオレン系化合物としては、例えば、特開昭６３−９４８７８号公報等に記載の化合物が挙げられる。
【００６２】
シアン、マゼンタ、イエローを発色する色素前駆体としては、米国特許第４，８００，１４９号明細書等に記載の各色素前駆体を使用することができる。さらに、イエロー発色色素用電子供与性染料前駆体としては、米国特許第４，８００，１４８号明細書等に記載の染料前駆体も使用することができ、シアン発色色素用電子供与性染料前駆体としては、特開平６３−５３５４２号公報等に記載の染料前駆体も使用することができる。
【００６３】
−電子受容性化合物−
上記（ａ）の組み合わせに用いられる電子受容性化合物としては、フェノール誘導体、サリチル酸誘導体、芳香族カルボン酸の金属塩、酸性白土、ペントナイト、ノボラック樹脂、金属処理ノボラック樹脂、金属錯体等の従来公知の電子受容性化合物が挙げられる。具体的には、特公昭４０−９３０９号公報、特公昭４５−１４０３９号公報、特開昭５２−１４０４８３号公報、特開昭４８−５１５１０号公報、特開昭５７−２１０８８６号公報、特開昭５８−８７０８９号公報、特開昭５９−１１２８６号公報、特開昭６０−１７６７９５号公報、特開昭６１−９５９８８号公報等に記載されている。
【００６４】
上記のうち、例えば、フェノール誘導体としては、２，２’−ビス（４−ヒドロキシフェニル）プロパン、４−ｔ−ブチルフェノール、４−フェニルフェノール、４−ヒドロキシジフェノキシド、１，１’−ビス（３−クロロ−４−ヒドロキシフェニル）シクロヘキサン、１，１’−ビス（４−ヒドロキシフェニル）シクロヘキサン、１，１’−ビス（３−クロロ−４−ヒドロキシフェニル）−２−エチルブタン、４，４’−ｓｅｃ−イソオクチリデンジフェノール、４，４’−ｓｅｃ−ブチリデンジフェノール、４−ｔｅｒｔ−オクチルフェノール、４−ｐ−メチルフェニルフェノール、４，４’−メチルシクロヘキシリデンフェノール、４，４’−イソペンチリデンフェノール、ｐ−ヒドロキシ安息香酸ベンジル等を挙げることができる。
【００６５】
上記サリチル酸誘導体としては、４−ペンタデシルサリチル酸、３，５−ジ（α−メチルベンジル）サリチル酸、３，５−ジ（ｔｅｒｔ−オクチル）サリチル酸、５−オクタデシルサリチル酸、５−α−（ｐ−α−メチルベンジルフェニル）エチルサリチル酸、３−α−メチルベンジル−５−ｔｅｒｔ−オクチルサリチル酸、５−テトラデシルサリチル酸、４−ヘキシルオキシサリチル酸、４−シクロヘキシルオキシサリチル酸、４−デシルオキシサリチル酸、４−ドデシルオキシサリチル酸、４−ペンタデシルオキシサリチル酸、４−オクタデシルオキシサリチル酸等、及びこれらの亜鉛、アルミニウム、カルシウム、銅、鉛塩等を挙げることができる。
【００６６】
発色成分として、電子供与性染料前駆体と電子受容性化合物との組み合わせを使用する場合、上記電子供与性染料前駆体は、記録層中に０．１〜５ｇ／ｍ^２の範囲で含有させることが好ましく、０．１〜１ｇ／ｍ^２の範囲で含有させることがより好ましい。また、上記電子受容性化合物の使用量は、使用する電子供与性無色染料１部に対して、０．５〜２０部の範囲であることが好ましく、３〜１０部の範囲であることがより好ましい。０．５部未満では、十分な発色濃度を得ることができない場合があり、２０部を超えると、感度が低下したり、塗布適性が劣化する場合があり好ましくない。
【００６７】
−ジアゾ化合物−
上記（ｂ）の組み合わせに使用可能なジアゾ化合物としては、下記式で表される化合物を用いることが好ましい。
Ａｒ−Ｎ_２ ^＋・Ｙ⁻
上記式中、Ａｒは芳香族環基を表し、Ｙ⁻は酸アニオンを表す。
【００６８】
上記式において、Ａｒは、置換または無置換のアリール基を表す。置換基としては、アルキル基、アルコキシ基、アルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アシル基、アルコキシカルボニル基、カルバモイル基、カルボアミド基、スルホニル基、スルファモイル基、スルホンアミド基、ウレイド基、ハロゲン基、アミノ基、ヘテロ環基、等が挙げられ、これら置換基は、さらに置換されていてもよい。
【００６９】
また、上記アリール基としては、炭素原子数６〜３０のアリール基であることが好ましく、例えば、フェニル基、２−メチルフェニル基、２−クロロフェニル基、２−メトキシフェニル基、２−ブトキシフェニル基、２−（２−エチルヘキシルオキシ）フェニル基、２−オクチルオキシフェニル基、３−（２，４−ジ−ｔ−ペンチルフェノキシエトキシ）フェニル基、４−クロロフェニル基、２，５−ジクロロフェニル基、２，４，６−トリメチルフェニル基、３−クロロフェニル基、３−メチルフェニル基、３−メトキシフェニル基、３−ブトキシフェニル基、３−シアノフェニル基、３−（２−エチルヘキシルオキシ）フェニル基、３，４−ジクロロフェニル基、３，５−ジクロロフェニル基、３，４−ジメトキシフェニル基、
【００７０】
３−（ジブチルアミノカルボニルメトキシ）フェニル基、４−シアノフェニル基、４−メチルフェニル基、４−メトキシフェニル基、４−ブトキシフェニル基、４−（２−エチルヘキシルオキシ）フェニル基、４−ベンジルフェニル基、４−アミノスルホニルフェニル基、４−Ｎ，Ｎ−ジブチルアミノスルホニルフェニル基、４−エトキシカルボニルフェニル基、４−（２−エチルヘキシルカルボニル）フェニル基、４−フルオロフェニル基、３−アセチルフェニル基、２−アセチルアミノフェニル基、４−（４−クロロフェニルチオ）フェニル基、４−（４−メチルフェニル）チオ−２，５−ブトキシフェニル基、４−（Ｎ−ベンジル−Ｎ−メチルアミノ）−２−ドデシルオキシカルボニルフェニル基、等が挙げられる。また、これらの基は、さらに、アルキルオキシ基、アルキルチオ基、置換フェニル基、シアノ基、置換アミノ基、ハロゲン原子、ヘテロ環基等により置換されていてもよい。
【００７１】
上記発色成分として好適に使用し得るジアゾ化合物としては、特開平７−２７６８０８号公報の第４４段落欄〜第４９段落欄に例示されるジアゾ化合物が挙げられる。
【００７２】
上記ジアゾ化合物の最大吸収波長λｍａｘは、４５０ｎｍ以下であることが好ましく、２９０〜４４０ｎｍであることがより好ましい。また、ジアゾ化合物は、炭素原子数が１２以上で、水に対する溶解度が１％以下で、かつ酢酸エチルに対する溶解度が５％以上であることが望ましい。
なお、本発明において、ジアゾ化合物は、単独で用いてもよいし、さらに色相調整等の目的に応じて、２種以上を併用することもできる。
【００７３】
−カプラー化合物−
上記（ｂ）の組み合わせに用いられるカプラー化合物は、塩基性雰囲気、及び／または、中性雰囲気で組み合わせて用いられるジアゾ化合物とカップリングして色素を形成するものであり、色相調整等種々目的に応じて、複数種を併用することが可能である。上記カプラー化合物としては、カルボニル基の隣にメチレン基を有するいわゆる活性メチレン化合物、フェノール誘導体、ナフトール誘導体等のカプラーを用いることが好ましい。具体的には、レゾルシン、フロログルシン、２，３−ジヒドロキシナフタレン、２，３−ジヒドロキシナフタレン−６−スルホン酸ナトリウム、１−ヒドロキシ−２−ナフトエ酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸ナトリウム、２−ヒドロキシ−３−ナフタレンスルホン酸アニリド、２−ヒドロキシ−３−ナフタレンスルホン酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸−２−エチルヘキシルオキシプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸−２−エチルヘキシルアミド、５−アセトアミド−１−ナフトール、
【００７４】
１−ヒドロキシ−８−アセトアミドナフタレン−３，６−ジスルホン酸ナトリウム、１−ヒドロキシ−８−アセトアミドナフタレン−３，６−ジスルホン酸ジアニリド、１，５−ジヒドロキシナフタレン、２−ヒドロキシ−３−ナフトエ酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフトエ酸オクチルアミド、２−ヒドロキシ−３−ナフトエ酸アニリド、５，５−ジメチル−１，３−シクロヘキサンジオン、１，３−シクロペンタンジオン、５−（２−ｎ−テトラデシルオキシフェニル）−１，３−シクロヘキサンジオン、５−フェニル−４−メトキシカルボニル−１，３−シクロヘキサンジオン、５−（２，５−ジ−ｎ−オクチルオキシフェニル）−１，３−シクロヘキサンジオン、Ｎ，Ｎ’−ジシクロヘキシルバルビツール酸、Ｎ，Ｎ’−ジ−ｎ−ドデシルバルビツール酸、
【００７５】
Ｎ−ｎ−オクチル−Ｎ’−ｎ−オクタデシルバルビツール酸、Ｎ−フェニル−Ｎ’−（２，５−ジ−ｎ−オクチルオキシフェニル）バルビツール酸、Ｎ，Ｎ’−ビス（オクタデシルオキシカルボニルメチル）バルビツール酸、１−フェニル−３−メチル−５−ピラゾロン、１−（２，４，６−トリクロロフェニル）−３−アニリノ−５−ピラゾロン、１−（２，４，６−トリクロロフェニル）−３−ベンズアミド−５−ピラゾロン、６−ヒドロキシ−４−メチル−３−シアノ−１−（２−エチルヘキシル）−２−ピリドン、２，４−ビス−（ベンゾイルアセトアミド）トルエン、１，３−ビス−（ピバロイルアセトアミドメチル）ベンゼン、ベンゾイルアセトニトリル、テノイルアセトニトリル、アセトアセトアニリド、ベンゾイルアセトアニリド、ピバロイルアセトアニリド、２−クロロ−５−（Ｎ−ｎ−ブチルスルファモイル）−１−ピバロイルアセトアミドベンゼン、１−（２−エチルヘキシルオキシプロピル）−３−シアノ−４−メチル−６−ヒドロキシ−１，２−ジヒドロピリジン−２−オン、１−（ドデシルオキシプロピル）−３−アセチル−４−メチル−６−ヒドロキシ−１，２−ジヒドロピリジン−２−オン、１−（４−ｎ−オクチルオキシフェニル）−３−ｔｅｒｔ−ブチル−５−アミノピラゾール等が挙げられる。
【００７６】
上記カプラー化合物の詳細は、特開平４−２０１４８３号公報、特開平７−２２３３６７号公報、特開平７−２２３３６８号公報、特開平７−３２３６６０号公報、特開平５−２７８６０８号公報、特開平５−２９７０２４号公報、特開平６−１８６６９号公報、特開平６−１８６７０号公報、特開平７−３１６２８０号公報、特開平９−２１６４６８号公報、特開平９−２１６４６９号公報、特開平９−３１９０２５号公報、特開平１０−０３５１１３号公報、特開平１０−１９３８０１号公報、特開平１０−２６４５３２号公報等に記載されたものも参照できる。
【００７７】
上記発色成分としてジアゾ化合物とカプラー化合物との組み合わせを使用する場合、上記ジアゾ化合物は、記録層中に０．０２〜５．０ｇ／ｍ^２の範囲で含有させることが好ましく、０．０５〜３．０ｇ／ｍ^２の範囲で含有させることがより好ましい。上記含有量が０．０２ｇ／ｍ^２未満では、十分な発色濃度を得ることができず、５．０ｇ／ｍ^２を超えると、塗布液の塗布適性が劣化するため好ましくない。また、上記カプラー化合物の使用量は、ジアゾ化合物１部に対し０．５〜２０部の範囲であることが好ましく、１〜１０部の範囲であることがより好ましい。０．５部未満では、十分な発色性を得ることができない場合があり、２０部を超えると、塗布適性が劣化する場合があり好ましくない。
【００７８】
上記カプラー化合物（所望により添加されるその他の成分とともに）は、水溶性高分子を添加して、サンドミル等により固体分散して用いることもできるが、適当な乳化助剤とともに乳化し、乳化物として用いることもできる。ここで、固体分散または乳化する方法としては、特に限定されるものではなく、従来公知の方法を利用することができる。これらの方法の詳細については、特開昭５９−１９０８８６号公報、特開平２−１４１２７９号公報、特開平７−１７１４５号公報に記載されている。
【００７９】
−有機塩基−
ジアゾ化合物とカプラーとのカップリング反応を促進する目的で、第３級アミン類、ピペリジン類、ピペラジン類、アミジン類、フォルムアミジン類、ピリジン類、グアニジン類、モルホリン類等の有機塩基を用いることが好ましい。これらの有機塩基としては、例えば、Ｎ，Ｎ’−ビス（３−フェノキシ−２−ヒドロキシプロピル）ピペラジン、Ｎ，Ｎ’−ビス〔３−（ｐ−メチルフェノキシ）−２−ヒドロキシプロピル〕ピペラジン、Ｎ，Ｎ’−ビス〔３−（ｐ−メトキシフェノキシ）−２−ヒドロキシプロピル〕ピペラジン、Ｎ，Ｎ’−ビス（３−フェニルチオ−２−ヒドロキシプロピル）ピペラジン、Ｎ，Ｎ’−ビス〔３−（β−ナフトキシ）−２−ヒドロキシプロピル〕ピペラジン、Ｎ−３−（β−ナフトキシ）−２−ヒドロキシプロピル−Ｎ’−メチルピペラジン、
【００８０】
１，４−ビス｛〔３−（Ｎ−メチルピペラジノ）−２−ヒドロキシ〕プロピルオキシ｝ベンゼンなどのピペラジン類；Ｎ−〔３−（β−ナフトキシ）−２−ヒドロキシ〕プロピルモルホリン、１，４−ビス〔（３−モルホリノ−２−ヒドロキシ）プロピルオキシ〕ベンゼン、１，３−ビス〔（３−モルホリノ−２−ヒドロキシ）プロピルオキシ〕ベンゼンなどのモルホリン類；Ｎ−（３−フェノキシ−２−ヒドロキシプロピル）ピペリジン、Ｎ−ドデシルピペリジンなどのピペリジン類；トリフェニルグアニジン、トリシクロヘキシルグアニジン、ジシクロヘキシルフェニルグアニジン、４−ヒドロキシ安息香酸２−Ｎ−メチル−Ｎ−ベンジルアミノエチルエステル、４−ヒドロキシ安息香酸２−Ｎ，Ｎ−ジ−ｎ−ブチルアミノエチルエステル、４−（３−Ｎ，Ｎ−ジブチルアミノプロポキシ）ベンゼンスルホンアミド、４−（２−Ｎ，Ｎ−ジブチルアミノエトキシカルボニル）フェノキシ酢酸アミド等；が挙げられる。
これらの有機塩基は、単独で用いてよいし、２種以上併用して用いてもよい。
【００８１】
前記有機塩基は、特開昭５７−１２３０８６号公報、特開昭６０−４９９９１号公報、特開昭６０−９４３８１号公報、特開平９−０７１０４８号公報、特開平９−０７７７２９号公報、特開平９−０７７７３７号公報等に記載されている。
【００８２】
また、前記有機塩基の使用量は、特に限定されるものではないが、ジアゾ化合物１モルに対して、１〜３０モルの範囲であることが好ましい。
【００８３】
−発色助剤−
さらに、発色反応を促進させる目的で、発色助剤を加えることもできる。
上記発色助剤としては、フェノール誘導体、ナフトール誘導体、アルコキシ置換ベンゼン類、アルコキシ置換ナフタレン類、ヒドロキシ化合物、カルボン酸アミド化合物、スルホンアミド化合物等が挙げられる。
【００８４】
−バインダー−
本発明における記録層は、上記発色成分とともにバインダーを含有していてもよい。当該バインダーとしては、水溶性のものが一般的であり、ポリビニルアルコール、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、エチレン−無水マレイン酸共重合体、スチレン−無水マレイン酸共重合体、イソブチレン−無水マレイン酸共重合体、ポリアクリル酸、デンプン誘導体カゼイン、ゼラチン等が挙げられる。また、これらのバインダーに耐水性を付与する目的で耐水化剤（ゲル化剤、架橋剤）を加えたり、疎水性ポリマーのエマルション、具体的には、スチレン−ブタジエンゴムラテツクス、アクリル樹脂エマルション等を加えることもできる。なお、バインダーは記録層中に乾燥質量で１０〜３０質量％の範囲で含有させるのが好ましい。
【００８５】
−その他−
記録層には、さらに消泡剤、螢光染料、着色染料、無機顔料、ワックス類、高級脂肪酸アミド、金属石ケン、紫外線吸収剤、酸化防止剤、ラテックス系バインダー等を必要に応じて添加することができる。また、感熱記録材料、感圧記録材料に使用されている各種添加剤を、記録層あるいはその他の層に含有させることも有効である。上記各種添加剤としては、特開昭６０−１２５４７０号公報、特開昭６０−１２５４７１号公報、特開昭６０−１２５４７２号公報、特開昭６０−２８７４８５号公報、特開昭６０−２８７４８６号公報、特開昭６０−２８７４８７号公報、特開昭６２−１４６６８０号公報、特開昭６０−２８７４８８号公報、特開昭６２−２８２８８５号公報、特開昭６３−８９８７７号公報、特開昭６３−８８３８０号公報、特開昭６３−０８８３８１号公報、特開平０１−２３９２８２号公報、特開平０４−２９１６８５号公報、特開平０４−２９１６８４号公報、特開平０５−１８８６８７号公報、特開平０５−１８８６８６号公報、特開平０５−１１０４９０号公報、特開平０５−１１０８４３７号公報、特開平０５−１７０３６１号公報、特開昭６３−２０３３７２号公報、特開昭６３−２２４９８９号公報、特開昭６３−２６７５９４号公報、特開昭６３−１８２４８４号公報、特開昭６０−１０７３８４号公報、特開昭６０−１０７３８３号公報、特開昭６１−１６０２８７号公報、特開昭６１−１８５４８３号公報、特開昭６１−２１１０７９号公報、特開昭６３−２５１２８２号公報、特開昭６３−０５１１７４号公報、特公昭４８−０４３２９４号公報、特公昭４８−０３３２１２号公報等に記載の化合物が挙げられる。
【００８６】
−マイクロカプセル−
記録層が熱、及び／または、圧力の供与によって発色するためには、前記発色成分の発色反応に熱応答性、及び／または、圧力応答性を付与することが好ましい。例えば、発色成分の一方を熱応答性、及び／または、圧力応答性のマクロカプセルに内包することによって、発色反応を熱応答性、及び／または、圧力応答性にすることができる。発色成分をマイクロカプセル化する方法としては、従来公知の方法を用いることができる。例えば、米国特許第２８００４５７号明細書、同２８０００４５８号明細書に記載の親水性壁形成材料のコアセルベーションを利用した方法、米国特許第３２８７１５４号明細書、英国特許第９９０４４３号明細書、特公昭３８−１９５７４号公報、同４２−４４６号公報、同４２−７７１号公報等に記載の界面重合法、米国特許第３４１８２５０号明細書、同３６６０３０４号明細書に記載のポリマー析出による方法、米国特許第３７９６６６９号明細書に記載のイソシアネートポリオール壁材料を用いる方法、米国特許第３９１４５１１号明細書に記載のイソシアネート壁材料を用いる方法、米国特許第４００１１４０号明細書、同４０８７３７６号明細書、同４０８９８０２号明細書に記載の尿素−ホルムアルデヒド系、尿素ホルムアルデヒド−レゾルシノール系壁形成材料を用いる方法、米国特許第４０２５４５５号明細書に記載のメラミン−ホルムアルデヒド樹脂、ヒドロキシブロビルセルロース等の壁形成材料を用いる方法、特公昭３６−９１６８号公報、特開昭５１−９０７９号公報に記載のモノマーの重合によるｉｎ ｓｉｔｕ法、英国特許第９５２８０７号明細書、同９６５０７４号明細書に記載の電解分散冷却法、米国特許第３１１１４０７号明細書、英国特許第９３０４２２号明細書に記載のスプレードライング法等が挙げられる。
【００８７】
前記発色成分をマイクロカプセル化する方法としては、一方の発色成分（上記（ａ）の組み合わせでは電子供与性染料前駆体、上記（ｂ）の組み合わせではジアゾ化合物）をカプセルの芯となる疎水性の有機溶媒に溶解または分散させ調製した油相を、水溶性高分子を溶解した水相と混合し、ホモジナイザー等の手段により乳化分散した後、加温することによってその油滴界面で高分子形成反応を起こし、高分子物質のマイクロカプセル壁を形成させる界面重合法を採用することが好ましい。この方法によれば、短時間内に均一な粒径のカプセルを形成することができ、生保存性にすぐれた記録材料とすることができる。
【００８８】
高分子を形成するリアクタントは、油滴内部、及び／または、油滴外部に添加される。高分子物質の具体例としては、ポリウレタン、ポリウレア、ポリアミド、ポリエステル、ポリカーボネート、尿素−ホルムアルデヒド樹脂、メラミン樹脂、ポリスチレン、スチレン−メタクリレート共重合体、スチレン−アクリレート共重合体等が挙げられる。中でも、ポリウレタン、ポリウレア、ポリアミド、ポリエステル、ポリカーボネートが好ましく、ポリウレタン、ポリウレアが特に好ましい。上記の高分子物質は、２種以上併用して用いることもできる。
【００８９】
前記水溶性高分子としては、例えば、ゼラチン、ポリビニルピロリドン、ポリビニルアルコール等が挙げられる。例えば、ポリウレタンをカプセル壁材として用いる場合には、多価イソシアネートおよびそれと反応してカプセル壁を形成する第２物質（例えば、ポリオール、ポリアミン）を水溶性高分子水溶液（水相）またはカプセル化すべき油性媒体（油相）中に混合し、これらを乳化分散した後、加温することにより油滴界面で高分子形成反応が生じ、マイクロカプセル壁を形成することができる。なお、マイクロカプセルの粒径は０．１〜１．０μｍの範囲であることが好ましく、０．２〜０．７μｍの範囲であることがより好ましい。
【００９０】
また、発色反応に熱応答性を付与する他の方法としては、前記発色成分の一方（例えば、（ａ）の組み合わせでは受容性化合物、（ｂ）の組み合わせではカプラー化合物、以下「顕色剤」という場合がある）に、低融点の熱可融性物質を混合し、共融物として記録層中に添加する方法や、低融点化合物が顕色剤粒子の表面に融着している状態として記録層に添加する方法が挙げられる。上記低融点化合物として使用される材料としては、ワックス類が挙げられ、ワックス類としては、パラフインワックス、カルナバワックス、マイクロクリスタリンワックス、ポリエチレンワックスの他、ステアリン酸アミド、エチレンビスステアロアミド等の高級脂肪酸アミド、高級脂肪酸エステル等が挙げられる。
【００９１】
上述の記録層は、前記発色成分、及び所望により添加されるバインダー等のその他の成分を溶解、及び／または、分散してなる塗布液を、支持体の樹脂層表面に塗布し、乾燥することによって形成することができる。上記塗布液の塗布方法としては、ブレード塗布法、エアナイフ塗布法、グラビア塗布法、ロールコーテイング塗布法、スプレー塗布法、ディップ塗布法、バー塗布法、エクストルージョン塗布法等の従来公知の塗布方法が利用可能である。
なお、記録層を形成する塗布液の塗布量は限定されるものではないが、乾燥質量で３〜１５ｇ／ｍ^２の範囲となることが好ましく、４〜１０ｇ／ｍ^２の範囲となることがより好ましい。
【００９２】
本発明の記録材料では、所望によって記録層間に中間層（２層以上の記録層を有する場合）、記録層表面に保護層及び紫外線（光透過率）調整層を設けることもできる。前記中間層には、必要に応じて、前記ＰＶＡ、オキシ塩化ビスマス及び硬膜剤を添加することができる。各層に含有される材料、及び各層の配置の例については、特開平１１−３４４９５号公報の第３９欄〜第６０欄に記載の材料や配置例が本発明の記録材料にも適用できる。
【００９３】
【実施例】
以下に本発明を実施例によって具体的に説明するが、本発明はこれらの実施例に限定されるものではない。尚、実施例中の「部」及び「％」は、特に断らない限り「質量部」及び「質量％」を表し、「平均分子量」及び「重合度」は、「重量平均分子量」及び「重量平均重合度」を表す。
＜実施例１＞
（支持体の調製）
（支持体の調製）
ＬＢＫＰ１００部からなる木材パルプを、ダブルディスクリファイナーによりカナディアンフリーネス３００ｍｌまで叩解し、エポキシ化ベヘン酸アミド０．５部、アニオンポリアクリルアミド１．０部、ポリアミドポリアミンエピクロルヒドリン０．１部、及びカチオンポリアクリルアミド０．５部を対パルプ絶乾重量比で添加し、長網抄紙機により秤量１５０ｇ／ｍ^２の原紙を抄造し、１．０ｇ／ｍ^２絶乾重量のポリビニルアルコールで表面サイズし、カレンダー処理によって密度１．０に調製した。
【００９４】
上記原紙のワイヤー面（裏面）にコロナ放電処理を行った後、溶融押出し機にて高密度ポリエチレンを樹脂厚が３５μｍとなるようコーティングし、マット面からなる裏面樹脂層を形成した。
【００９５】
また、原紙のフェルト面（表面）側にはコロナ放電処理を行った後、アナターゼ型二酸化チタン１０部及び微量の群青を含有した低密度ポリエチレンを熱溶融押出し機にて樹脂厚が３０μｍとなるようコーティングし、光沢面からなる表面樹脂層を形成した。
【００９６】
（下塗り層の形成）
−下塗り用塗布液の調製−
（１）アセトアセチル変性ポリビニルアルコール溶液
アセトアセチル変性ポリビニルアルコール（ケン化度９５〜９７％、重合度約１０００、商品名：ゴーセファイマーＺ−２１０、日本合成化学工業社製）１２．８５部を、水８７．１５部に加え８０℃以上で攪拌溶解をし、濃度が１２．８５％のアセトアセチル変性ポリビニルアルコール溶液を調製した。
（２）６５％オキシ塩化ビスマス分散液
６５％オキシ塩化ビスマス分散液（商品名：Ｂｉ−Ｆｌａｉｒ ８４（粒子径：５〜２５μｍ）、オキシ塩化ビスマス／アクリル樹脂／酢酸イソプロピル＝５５／１０／４５）、ＭＥＲＣＫ社製）を準備した。
（３）１．６６％界面活性剤溶液
エチレンオキサイド系界面活性剤（Ｃ_１２Ｈ_２５Ｏ（ＣＨ_２ＣＨ_２Ｏ）_１０Ｈ、商品名：エマレックス７１０、日本エマルジョン（株）製）の１．６６％（メタノール溶解）溶液を調製した。
（４）４％２−エチレンスルホニル−Ｎ−［２−（２−エチレンスルホニル−アセチルアミノ）−エチル］−アセトアミド水溶液
２−エチレンスルホニル−Ｎ−［２−（２−エチレンスルホニル−アセチルアミノ）−エチル］−アセトアミドの４％水溶液を調製した。
【００９７】
（１）の１２．８５％アセトアセチル変性ポリビニルアルコール溶液１００部に対し、水８３部、及びメタノール１１９部を加え、十分攪拌混合した後、（２）の６５％オキシ塩化ビスマス分散液４７部加え、十分攪拌混合し、さらに（３）の１．６６％界面活性剤溶液８部、（４）の４％２−エチレンスルホニル−Ｎ−［２−（２−エチレンスルホニル−アセチルアミノ）−エチル］アセトアミド水溶液３部を加えた。そして、液温度を３０〜４０℃に保ち、１２．１％の下塗り層用塗布液を得た。
【００９８】
−下塗り層の形成−
前記支持体表面の樹脂層をコロナ放電処理した後、上記下塗り層塗布液を、乾燥後塗布量が２．５ｇ／ｍ^２となるような厚みに斜線６５メッシュグラビアロールにて塗布し、下塗り層を形成した。
【００９９】
（記録層の形成）
［記録層用塗布液Ａの調製］
−電子供与性染料前駆体カプセル液の調製−
電子供与性染料前駆体として、クリスタルバイオレットラクトン３．０部を酢酸エチル２０部に溶解し、さらに高沸点溶媒であるアルキルナフタレンを２０部添加し、加熱して均一に混合した。次いでカプセル壁剤として、キシレンジイソシアナート／トリメチロールプロパン付加物２０部をこの溶液にさらに添加し、均一に攪拌して電子供与性染料前駆体溶液を得た。
別途、ゼラチンの６％水溶液５４部を用意し、これに上記電子供与性染料前駆体溶液を添加し、ホモジナイザーにて乳化分散した。得られた乳化液に水６８部を加え、均一化した後、攪拌しながら５０℃に昇温し、３時間カプセル化反応を行わせることにより目的の電子供与性染料前駆体カプセル液を得た。カプセルの平均粒子径は１．６μｍであった。
【０１００】
・電子受容性化合物分散液の調製
電子受容性化合物として、ビスフェノールＡ３０部をゼラチンの４質量％水溶液１５０部中に加えてボールミルにて２４時間分散することにより、電子受容性化合物分散液を調整した。分散液中の電子受容性化合物の平均粒子径は１．２μｍであった。
【０１０１】
−塗布液の調製−
次いで、上記電子供与性染料前駆体カプセル液及び上記電子受容性化合物分散液を、電子供与性染料前駆体／電子受容性化合物の質量比率が１／２となるように混合し、目的の記録層用塗布液Ａを得た。
【０１０２】
［記録層用塗布液Ｂの調製］
−ジアゾニウム塩化合物カプセル液ｂの調製−
ジアゾニウム塩化合物として４−（Ｎ−（２，４−ジ−ｔｅｒｔ−アミルフェノキシ）ブチリル）ピペラジノベンゼンジアゾニウムヘキサフルオロフォスフェート２．０部を、酢酸エチル２０部に溶解し、さらに高沸点溶媒であるアルキルナフタレンを２０部添加し、加熱して均一に混合した。カプセル壁剤として、キシレンジイソシアナート／トリメチロールプロパン付加物１５部をこの溶液にさらに添加し、均一に攪拌してジアゾニウム塩化合物溶液を得た。
別途、ゼラチンの６％水溶液５４部を用意し、これに上記ジアゾニウム塩化合物溶液を添加し、ホモジナイザーにて乳化分散した。得られた乳化液に水６８部を加え均一化した後、攪拌しながら４０℃に昇温し、３時間カプセル化反応を行わせることにより目的のジアゾニウム塩化合物カプセル液ｂを得た。カプセルの平均粒子径は１．１μｍであった。
【０１０３】
−カプラー乳化液ｂの調製−
カプラーとして１−（２’−オクチルフェニル）−３−メチル−５−ピラゾロン２部、１，２，３−トリフェニルグアニジン２部、１，１−（ｐ−ヒドロキフェニル）−２−エチルヘキサン２部、４，４’−（ｐ−フェニレンジイソプロピリデン）ジフェノール４部、２−エチルヘキシル−４−ヒドロキシベンゾエート４部、トリクレジルホスフェート０．３部、マレイン酸ジエチル０．１部、及び７０％ドデシルベンゼンスルホン酸カルシウムのメタノール溶液１部を酢酸エチル１０部に溶解し、この溶液を８％ゼラチン水溶液８０部に添加し、ホモジナイザーで１０分間乳化分散した後、酢酸エチルを除去して目的のカプラー乳化液ｂを得た。
【０１０４】
−塗布液の調製−
次いで、上記のジアゾニウム塩化合物カプセル液ｂ及び上記のカプラー乳化液ｂを、ジアゾニウム塩化合物／カプラーの質量比率が２／３となるように混合し、目的の記録層用塗布液Ｂを得た。
【０１０５】
［記録層用塗布液Ｃの調製］
−ジアゾニウム塩化合物カプセル液ｃの調製−
ジアゾニウム塩化合物として２，５−ジブトキシ−４−トリルチオベンゼンジアゾニウムヘキサフルオロフォスフェート３．０部を、酢酸エチル２０部に溶解し、さらに高沸点溶媒であるアルキルナフタレンを２０部添加し、加熱して均一に混合した。カプセル壁剤として、キシレンジイソシアナート／トリメチロールプロパン付加物１５部をこの溶液にさらに添加し、均一に攪拌してジアゾニウム塩化合物溶液を得た。
別途、ゼラチンの６質量％水溶液５４部を用意し、これに上記ジアゾニウム塩化合物溶液を添加し、ホモジナイザーにて乳化分散した。得られた乳化液に水６８部を加え均一化した後、攪拌しながら４０℃に昇温し、３時間カプセル化反応を行わせることにより目的のジアゾニウム塩化合物カプセル液ｃを得た。カプセルの平均粒子径は１．０μｍであった。
【０１０６】
−カプラー乳化液ｃの調製−
カプラーとして２−クロロ−５−（３−（２，４−ジ−ｔｅｒｔ−ペンチル）フェノキシプロピルアミノ）アセトアセトアニリドを２部、１，２，３−トリフェニルグアニジン２部、１，１−（ｐ−ヒドロキシフェニル）−２−エチルヘキサン２部、４，４’−（ｐ−フェニレンジイソプロピリデン）ジフェノール４部、２−エチルヘキシル−４−ヒドロキシベンゾエート４部、トリクレジルホスフェート０．３部、マレイン酸ジエチル０．１部、及び７０％ドデシルベンゼンスルホン酸カルシウムのメタノール溶液１部を酢酸エチル１０部に溶解し、この溶液をの８％ゼラチン水溶液８０部に添加し、ホモジナイザーで１０分間乳化分散した後、酢酸エチルを除去することにより目的のカプラー乳化液ｃを得た。
【０１０７】
−塗布液の調製−
次いで、上記のジアゾニウム塩化合物カプセル液ｃ及び上記のカプラー乳化液ｃを、ジアゾニウム塩化合物／カプラーの質量比率が４／５となるように混合し、目的の記録層用塗布液Ｃを得た。
【０１０８】
［光透過率調整用塗布液の調製］
−紫外線吸収剤前駆体カプセル液の調製−
酢酸エチル３０部に、紫外線吸収剤前駆体として〔２−アリル−６−（２Ｈ−ベンゾトリアゾール−２−イル）−４−ｔ−オクチルフェニル〕ベンゼンスルホナート１０部、２，５−ジ−ｔ−オクチル−ハイドロキノン３部、トリクレジルフォスフェート２部、α−メチルスチレンダイマー４部を溶解した。カプセル壁剤としてキシレンジイソシアナート／トリメチロールプロパン付加物２０部をこの溶液にさらに添加し、均一に攪拌し、紫外線吸収剤前駆体溶液を得た。
別途、イタコン酸変性ポリビニルアルコールの８％水溶液２００部を用意し、これに上記紫外線吸収剤前駆体溶液を添加し、ホモジナイザーにて乳化分散した。得られた乳化液に水１２０部を加え均一化した後、攪拌しながら４０℃に昇温し、３時間カプセル化反応を行わせ目的の紫外線吸収剤前駆体カプセル液を得た。カプセルの平均粒子径は０．３μｍであった。
【０１０９】
−塗布液の調製−
上記紫外線吸収剤前駆体カプセル液１００部に、（４−ノニルフェノキシトリオキシエチレン）ブチルスルホン酸ナトリウムの２％水溶液１０部を添加し光透過率調整用塗布液を得た。
【０１１０】
［中間層用塗布液の調製］
１０％ゼラチン水溶液１００部に、（４−ノニルフェノキシトリオキシエチレン）ブチルスルホン酸ナトリウムの２％水溶液２部を添加し中間層用塗布液を得た。
【０１１１】
［保護層用塗布液の調製］
５％エチレン変性ポリビニルアルコール水溶液６１部に、２０．５％ステアリン酸亜鉛の分散液（ハイドリンＦ１１５、中京油脂社製）２．０部を添加し、２質量（４−ノニルフェノキシトリオキシエチレン）ブチルスルホン酸ナトリウム水溶液８．４部と、フッ素系離型剤（ＭＥ−３１３、ダイキン社製）８部と、小麦粉澱粉０．５部と、を添加し均一に攪拌し、ポリビニルアルコール液を調製した。
別途、２０％カオグロス（白石工業社製）水溶液１２．５部と、１０％ポリビニルアルコール（ＰＶＡ１０５、クラレ社製）水溶液１．２５部と、２％ドデシルスルホン酸ナトリウム水溶液０．３９部と、を混合し、ダイノミルにて分散し顔料液を調製した。
上記ポリビニルアルコール液８０部に、上記顔料液４．４部を添加して保護層用塗布液を調製した。
【０１１２】
［記録層の形成］
前記下塗り層を形成した印画紙用支持体表面に、前記各塗布液を用いて、下層から記録層Ａ、中間層、記録層Ｂ、中間層、記録層Ｃ、光透過率調整層、保護層の順に、６０ｍ／ｍｉｎの塗布速度で７層同時に連続塗布し、３０℃−３０％ＲＨの条件及び４０℃−３０％ＲＨの条件でそれぞれ乾燥して多色感熱記録材料を作製した。なお、固形分塗布量は順に、記録層Ａが６．０ｇ／ｍ^２、中間層が３．０ｇ／ｍ^２、記録層Ｂが６．０ｇ／ｍ^２、中間層が３．０ｇ／ｍ^２、記録層Ｃが５．０ｇ／ｍ^２、光透過率調整層が３．０ｇ／ｍ^２、保護層が１．５ｇ／ｍ^２となるように塗布した。
【０１１３】
＜実施例２＞
実施例１の下塗り層用塗布液の調製において、水８３部、メタノール１１９部、６５％オキシ塩化ビスマス分散液４７部、１．６６％界面活性剤液８部を使用し、乾燥後塗布量が２．５ｇ／ｍ^２となるような下塗り層を形成する代わりに、水１１６部、メタノール１３６部、６５％オキシ塩化ビスマス分散液２．３部、１．６６％界面活性剤液３部を使用し、乾燥後塗布量が０．９ｇ／ｍ^２をとなるような下塗り層を形成することとした以外は、実施例１と同様にして記録材料を作製した。尚、本実施例で使用した下塗り用塗布液の濃度は４．０％であった。
【０１１４】
＜実施例３＞
実施例１の下塗り層用塗布液の調製において、水８３部、メタノール１１９部、６５％オキシ塩化ビスマス分散液４７部、１．６６％界面活性剤液８部を使用し、乾燥後塗布量が２．５ｇ／ｍ^２となるような下塗り層を形成する代わりに、水３７６部、メタノール３３６部、６５％オキシ塩化ビスマス分散液２３４部、１．６６％界面活性剤液３０部を使用し、乾燥後塗布量が３．２ｇ／ｍ^２をとなるような下塗り層を形成することとした以外は、実施例１と同様にして記録材料を作製した。尚、本実施例で使用した下塗り用塗布液の濃度は１５．３％であった。
【０１１５】
＜比較例１＞
実施例１の、原紙の両面にポリエステルフィルムをラミネートした印画紙用支持体の塗布面側にコロナ放電処理後、下塗り層を形成せずに、記録層を形成することとした以外は、実施例１と同様にして記録材料を作製した。
【０１１６】
＜比較例２＞
実施例１の水８３部、メタノール１１９部、６５質量％オキシ塩化ビスマス分散液４７部、１．６６％界面活性剤８部を使用し、乾燥後塗布重量が２．５ｇ／ｍ^２となるように下塗層を形成する代わりに、 水１１８部、メタノール１３６部、１．６６％界面活性剤２部を使用し、乾燥後塗布重量が０．７６ｇ／ｍ^２となるような下塗層を形成することとした以外は、実施例１と同様にして記録材料を作製した。尚、本比較例で使用した下塗用塗布液の濃度は、３．６％であった。
【０１１７】
＜評価＞
上記より得られた本発明の多色感熱記録材料の実施例１〜３、並びに比較例１、２の各々について、以下の評価試験を行った。試験の結果は下記表２に示す。
【０１１８】
（１）支持体の正反射率測定
実施例１〜３、比較例１、２における記録層を積層する前の支持体について、日立製カラーアナライザー６０７型にて４４０ｎｍにおける全反射率、拡散反射率を測定し、全反射率と拡散反射率の値を測定し、その値の差から正反射率を求めた。基準としては、前記正反射率が２％以上であれば、記録層形成後の画像にくっきり感を与えることができる。各記録材料用支持体の正反射率評価結果を表２に示す。
【０１１９】
（２）支持体の粉落ち評価
実施例１〜３、比較例１、２における記録層を積層する前の支持体について、摩擦試験機（ＨＥＩＤＯＮ−１８、新東科学（株）製）を用い、９００ｇのおもりをサンプル上で回転させ、サンプル表面の粉落ちの程度を評価した。粉落ちがほとんど無い場合を○、粉落ちがやや生じる場合を△、粉落ちが多い場合を×として、評価した。
【０１２０】
（３）画質評価
実施例１〜３、比較例１、２の記録材料に対して、下記表１に示される条件を最高出力とし、順次出力を下げ、各出力ごとにデジタルカラープリンター（商品名ＮＣ３７０Ｄ、富士写真フィルム社製）を使用して記録される種々の画像を印画し、特に細線部に着目して画質を目視評価した。
評価基準は、比較印画サンプル（Ｔｈｅｒｍｏ−Ａｕｔｏｃｈｒｏｍｅ Ｐａｐｅｒ ＲＡ５−Ｇ１００、富士写真フイルム社製）の細線部に比べ、より鮮明かつ奥行き感のあるレベルを○とし、同等レベルを△とし、劣るレベルを×とし、各記録材料の画質評価結果を表２に示す。
【０１２１】
【表１】

【０１２２】
（４）地肌耐光性評価
実施例１〜３、比較例１、２の記録材料に対して、発光中心波長３６５ｎｍの紫外線ランプ下に１５秒間さらし定着した後、ＷＥＡＴＨＥＲＯＭＥＴＥＲ ＣＩ ６５（ＡＴＬＡＳ ＥＬＥＣＴＲＩＣ ＤＥＶＩＣＥＳ ＣＯ．製）により、０．９Ｗ／ｍ^２で１２０時間照射処理した。照射処理前後のサンプルをＸ−ｒｉｔｅ反射濃度計（イエロー成分）で測定し、その差（ΔＤｍｉｎ）を求め、評価した。各記録材料の地肌耐光性評価結果を表２に示す。
【０１２３】
【表２】

【０１２４】
表２の結果から、実施例１〜３の記録材料は、比較例１、２に比べ正反射率が高く、輝き感や奥行き感が得られることによりインパクトが生じ、くっきり感、鮮鋭度の高い画像が得られた。また実施例１〜３の記録材料は、同時に地肌耐光性も良好であった。
【０１２５】
【発明の効果】
本発明によれば、白地部に特徴ある白色性を付与することにより、シャープネス（解像度）とブライトネス（輝き感）とを向上させ、これにより奥行き感のある画像を形成するとともに、地肌耐光性が改良された感熱・感圧記録材料を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording material, and more particularly to a recording material that can be recorded by a thermal head or the like.
[0002]
[Prior art]
In recent years, heat-sensitive and pressure-sensitive recording materials that record images by supplying heat with a thermal head, etc. have been remarkable because of their advantages such as simple recording devices, high reliability, and no maintenance. Evolving. The recording material has a recording layer containing, for example, an electron-donating dye precursor and an electron-accepting compound or a diazonium salt compound and a coupler as a color-forming component on the support surface. An image is recorded by utilizing a color developing reaction that proceeds by the provision of the above.
[0003]
Under such circumstances, in recent years, the heat-sensitive and pressure-sensitive recording materials are required to have higher functions that are differentiated from conventional functions. In order to meet such demands, extensive research has been conducted on the sharpness and brightness from the support coating layer and the undercoat layer for the heat-sensitive recording material, the diffuse reflection, the coated surface, and the image light resistance.
[0004]
Conventionally, in heat-sensitive / pressure-sensitive recording materials, a layer containing inorganic particles such as titanium oxide, aluminum oxide, zinc oxide, calcium carbonate, calcium sulfate, mica as a pigment substance or a light-reflective filler is supported. Although it is used as a body coating layer, undercoat layer, etc., it has been obtained that can satisfy all the quality requirements such as sharpness (resolution), brightness (brightness), depth image and light resistance of the image at the same time. There wasn't.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems of the prior art. That is,
An object of the present invention is to provide a heat-sensitive / pressure-sensitive recording material that improves sharpness (resolution) and brightness (brightness), thereby forming an image with a sense of depth, and improved background light resistance. And
[0006]
[Means for Solving the Problems]
The above-mentioned subject is achieved by the following present invention. That is, the present invention
[0007]
<1> A recording material having a recording layer capable of color development by application of heat and / or pressure on a support, wherein polyvinyl alcohol, bismuth oxychloride and a hardener are provided on the recording layer side of the support. A recording material, comprising at least one layer containing the above.
<2> The recording material according to <1>, wherein the support is formed by coating a polyolefin resin on both sides of a paper substrate.
<3> The recording material according to <1> or <2>, wherein the main particle size of the bismuth oxychloride is 5 to 25 μm and the average thickness is 100 to 250 nm.
[0008]
<4> Any one of the above <1> to <3>, wherein a mass ratio (x / y) between the bismuth oxychloride (x) and the polyvinyl alcohol (y) is 0.1 or more and 10 or less 2. Recording material according to item 1.
<5> The recording material according to any one of <1> to <4>, wherein the polyvinyl alcohol is acetoacetyl-modified polyvinyl alcohol having a degree of polymerization of 1000 or more.
<6> The hardener is Hammett σ._pThe recording material according to any one of <1> to <5>, wherein the recording material is a compound having two or more vinyl groups adjacent to a substituent having a positive value in a single molecule.
[0009]
<7> The recording material according to any one of <1> to <6>, wherein the recording layer includes a plurality of layers that color yellow, magenta, or cyan.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the recording material of the present invention will be described in detail.
The recording material of the present invention is a recording material having a recording layer capable of color development by application of heat and / or pressure on a support, and polyvinyl alcohol (hereinafter referred to as “hereinafter referred to as“ polyvinyl alcohol ”) on the recording layer side of the support. PVA "), bismuth oxychloride and a hardener containing at least one layer. The layer containing polyvinyl alcohol, bismuth oxychloride and a hardener is preferably formed between the support and the recording layer, but is not particularly limited, and is formed on the recording layer side of the support. It can be formed as an intermediate layer in the recording layer, or it can be formed by containing the polyvinyl alcohol, bismuth oxychloride and a hardener in the intermediate layer as required.
Hereinafter, the layer containing polyvinyl alcohol, bismuth oxychloride and a hardener will be referred to as an undercoat layer.
[0011]
(Undercoat layer)
The undercoat layer according to the present invention is a layer containing PVA, bismuth oxychloride and a hardener, and is located between the support and the recording layer. The regular reflection from the undercoat layer is enhanced, and quality such as sharpness and brightness can be satisfied. Furthermore, an image with a sense of depth can be formed, and at the same time, oxygen can be transmitted. Generation | occurrence | production of the blister by suppressing can be suppressed, and background coloring can be prevented. Furthermore, it is excellent in water resistance, and it can suppress that a recording layer peels from a support body. Hereinafter, the components contained in the undercoat layer will be described in detail.
[0012]
-Bismuth oxychloride-
The undercoat layer of the support of the present invention contains the bismuth oxychloride. The said bismuth oxychloride belongs to a pearl luster pigment, and shows silver-white type pearl luster.
[0013]
The pearl luster pigment refers to a pigment capable of giving a pearly shine by utilizing light reflection / interference phenomenon. As a pearlescent pigment, it is a thin crystal with a high refractive index, so that reflection of light occurs at the boundary between the vehicle and the crystal surface, and when all the incident light is reflected, it becomes total reflection and becomes a metal or mirror. It becomes like a real pearl by gathering a lot of reflective and partially refracting surfaces. Such reflection is referred to as multi-layer reflection, but light is reflected from the inside, resulting in a deep gloss. When flat particles having a high refractive index are uniformly dispersed in a transparent resin and arranged in parallel to the surface of the resin, an ideal silver-white pearlescent pigment is obtained. On the other hand, by coating a flaky substrate surface with a transparent or translucent metal oxide having a high refractive index, such as titanium mica, multilayer reflection and reflected light from both the surface and the coating interface are reflected. There are pigments and the like that develop silver color or interference color by mutual interference action.
[0014]
In the present invention, bismuth oxychloride is included in the undercoat layer of the support, and the regular reflectance from the bottom of the recording layer is increased to give the image a sense of brightness and depth, as well as a sharpness and sharpness. The degree can be improved. As the pearlescent pigment, natural pearl essence obtained by extracting and purifying from other fish scales, basic carbonate plate crystals and mica that can be mass-produced with high quality by synthesis, anatase type on the surface There are those coated with titanium dioxide or rutile titanium dioxide.
In the present invention, the regular reflectance is obtained by subtracting the diffuse reflectance from the total reflectance.
[0015]
The bismuth oxychloride has various physical properties, but is preferably bismuth oxychloride having a refractive index of 2.15. Bismuth oxychloride can be produced by a known method. For example, bismuth trichloride is hydrolyzed in dilute hydrochloric acid to obtain bismuth oxychloride crystals. The crystals are collected by filtration and washed with water, and then the pH is adjusted to near neutral with caustic soda water, and the resulting crystals are collected by filtration, washed with water and dried. In addition, from the viewpoint of light resistance, coating treatment with cerium hydroxide or the like is also possible.
In addition, it is more convenient if a commercial item is used. Commercially available flaky bismuth oxychloride includes trade name “BIRON MTU” (Merck), trade name “Biron LF-2000” (Merck), trade name “Bi-Fair 84” (Merck), Trade name “Mearlite Radiant Pearl STL” (manufactured by Angelhard Asia Pacific Inc.), trade name “Mearlite Radiant Pearl SUQ” (manufactured by Engelhard Asia Pacific Inc.), trade name “BBInc (manufactured by BfE”) It is done.
[0016]
The main particle size of the bismuth oxychloride is preferably in the range of 5 to 25 μm, and more preferably in the range of 10 to 20 μm. In particular, the main particle size is most preferably in the range of 15 to 20 μm. If the main particle size is less than 5 μm, the surface of the recording material may not be bright, and if the particle size exceeds 25 μm, the surface of the recording material may be glaring. Here, the above-mentioned “main particle size” means that 90% by mass or more of the total particles exist within this range, and the particle size distribution measuring device LA910 (manufactured by Horiba) is adjusted to a dilute aqueous dispersion. Can be measured.
[0017]
The thickness of the bismuth oxychloride in the present invention is preferably in the range of 100 to 250 nm. Among them, the regular reflectance is improved as the aspect ratio is increased, and thus the thickness is preferably in the range of 100 to 160 nm. .
[0018]
Furthermore, for diffuse reflection control, the thinner the better, the better the particle size, as long as the smoothness and transparency of the coated surface are not impaired. If the particle size is smaller than 5 μm, the glittering feeling on the surface of the recording material may not be obtained. On the other hand, if the particle size is larger than 25 μm, the glare may appear on the surface of the recording material. Further, the aspect ratio of the bismuth oxychloride is preferably 10 or more, more preferably 15 or more, and further preferably 20 or more from the viewpoint of increasing the effect of improving sharpness and brightness.
[0019]
The addition amount of the bismuth oxychloride is preferably in the range of 10 to 1000%, more preferably in the range of 50 to 500% with respect to the polyvinyl alcohol. If the amount is less than 10%, the effect as a pigment may not be sufficiently exhibited. If the amount is more than 1000%, dispersibility is insufficient or powdering occurs (the amount of pigment increases with respect to PVA, and the retention of the pigment decreases). In some cases, the production is not stable.
[0020]
The mass ratio (x / y) between the mass (x) of the bismuth oxychloride and the mass (y) of polyvinyl alcohol contained in the undercoat layer is preferably in the range of 0.1 to 10; A range of 5 to 5 is more preferable.
When the mass ratio is less than 0.1, the effect as a pigment may not be sufficiently exhibited. When the mass ratio exceeds 10, the dispersibility is insufficient or the occurrence of powder falling (pigment with respect to PVA). In some cases, the stability of the production is lacking.
[0021]
(PVA)
The undercoat layer in the present invention contains the PVA. The PVA according to the present invention also includes those containing modified PVA such as acetoacetyl-modified PVA or ethylene-modified PVA. Polyvinyl alcohol is abbreviated as PVA.
[0022]
Examples of PVA in the present invention include fully saponified PVA, partially saponified PVA, carboxylic acid-modified PVA, maleic acid-modified PVA, silanol-modified PVA, cation-modified PVA, ethylene oxide-modified PVA, and acetoacetyl-modified PVA. PVA having a degree of polymerization of 500 or more is preferable, and PVA having a degree of polymerization of 1000 or more is more preferable in terms of large oxygen permeation suppression and high SS characteristics.
Here, the SS characteristic means a tensile energy absorption amount (toughness) expressed by stress-elongation until the film breaks. Therefore, the undercoat layer exhibits a water resistance effect and an oxygen permeation suppressing effect, and freely expands and contracts even when heated by a thermal head, so that no cracks are generated and no blisters are generated.
[0023]
In the present invention, PVA can be used in combination of two or more of the aforementioned PVA, and from the viewpoint of water resistance, it is preferable to use at least one acetoacetyl-modified PVA in combination with a hardener described below. The addition amount of acetoacetyl-modified PVA is 30% by mass or more, preferably 50% by mass or more of the total binder amount.
[0024]
In the present invention, when the acetoacetyl-modified PVA is used, the modification rate is preferably 0.05 to 15 mol%, and from the viewpoint of water resistance and thickening of the coating solution, in particular, 3 to 10 mol%. More preferably. If the modification rate is less than 3 mol%, the water resistance may not be obtained when the pH of the coating solution is 6 or less. If it exceeds 10 mol%, the reaction in the coating solution proceeds and gelation occurs. May end up.
[0025]
The degree of polymerization of PVA used in the present invention is preferably 1000 or more, and more preferably 1000 or more and 2000 or less from the viewpoint of leveling properties of the coating solution.
When the polymerization degree of the PVA is 1000 or more, the effect of suppressing the occurrence of cracks in a low humidity environment (for example, 20 ° C., 10%) is increased. This is considered to be due to the fact that the strength and elongation at break can be remarkably increased by increasing the degree of polymerization to 1000 or more.
When the polymerization degree of the PVA is 2000 or more, the coated surface state may be deteriorated due to a decrease in leveling property of the coating solution.
Furthermore, although the oxygen permeability increases due to the decrease in the bismuth oxychloride ratio in the mass ratio of the PVA and the bismuth oxychloride, it can be compensated by increasing the degree of polymerization of PVA.
[0026]
The saponification degree of PVA used in the present invention is not particularly limited, but is preferably 30 to 99 mol%, from the viewpoint of solubility in an alcohol-water mixed solvent and water resistance after film formation. Especially, it is more preferable that it is 60-97 mol%.
If the degree of saponification decreases, the elongation at break increases. Further, when the degree of polymerization is high, the degree of saponification increases, but when the degree of polymerization is low, it is preferable to reduce the degree of saponification. Further, when the degree of saponification is lowered, the elongation can be increased, while the solubility in methanol is increased, and there is an advantage that the viscosity is lowered and the leveling of the coated surface is improved and the coated surface state is improved.
[0027]
-Hardener-
A hardening agent is preferably used in order to improve the water resistance of the recording material by reacting with PVA such as acetoacetyl-modified PVA. Moreover, it can suppress that a recording layer peels from a support body. Examples of the hardener include diol compounds, epoxy compounds, blocked isocyanates, vinyl sulfone compounds, aldehyde compounds, methylol compounds, boric acid, carboxylic acid anhydrides, silane compounds, chelate compounds, and halogen compounds.
[0028]
As the hardener in the undercoat layer, Hammett's substituent constant σ_pA compound having two or more vinyl groups adjacent to a substituent having a positive value in a single molecule is preferable.
In the undercoat layer in the present invention, Hammett's substituent constant σ as a hardener_pBy containing a compound having two or more vinyl groups adjacent to a substituent having a positive value in a single molecule, it reacts with the PVA such as the acetoacetyl-modified PVA to increase the viscosity of the coating solution for the undercoat layer. Therefore, the water resistance of the recording material can be improved, and as a result, a recording material having improved water resistance of the recording material and coating stability of the coating solution for the undercoat layer can be obtained.
[0029]
Hammett's substituent constant σ_pExamples of the substituent having a positive value include CF₃Group (σ_pValue: 0.54), CN group (σ_pValue: 0.66), COCH₃Group (σ_pValue: 0.50), COOH group (σ_pValue: 0.45), COOR group (R represents an alkyl group) (σ_pValue: 0.45), NO₂Group (σ_pValue: 0.78), OCOCH₃Group (σ_pValue: 0.31), SH group (σ_pValue: 0.15), SOCH₃Group (σ_pValue: 0.49), SO₂CH₃Group (σ_pValue: 0.72), SO₂NH₂Group (σ_pValue: 0.57), SCOCH₃Group (σ_pValue: 0.44), F group (σ_pValue: 0.06), Cl group (σ_pValue: 0.23), Br group (σ_pValue: 0.23), group I (σp value: 0.18), IO₂Group (σ_pValue: 0.76), N⁺(CH₃)₃Group (σ_pValue: 0.82), S⁺(CH₃)₂Group (σ_pValue: 0.90).
[0030]
Hammett's substituent constant σ_pExamples of the compound having two or more vinyl groups adjacent to a substituent having a positive value in a single molecule include 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] acetamide, In addition to bis-2-vinylsulfonylethyl ether, bisacryloylimide, NN′-diaacryloyl urea, 1,1-bisvinylsulfoneethane, ethylene-bis-acrylamide, diacrylate and diacrylate represented by the following structural formula Examples thereof include methacrylate compounds, among which 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] acetamide is particularly preferable.
[0031]
[Chemical 1]

[0032]
Hammett's substituent constant σ in the undercoat layer_pThe content of the compound having two or more vinyl groups adjacent to a substituent having a positive value in a single molecule is in the range of 0.1 to 30 parts with respect to 100 parts of PVA such as acetoacetyl-modified PVA. It is preferable that the range is 0.5 to 10 parts.
[0033]
-Layered inorganic compound-
A layered inorganic compound can be further added to the undercoat layer. As the layered inorganic compound, a swellable inorganic layered compound is preferable. Examples include synthetic smectite. These swellable inorganic layered compounds have a laminated structure composed of unit crystal lattice layers having a thickness of 10 to 15 angstroms, and the substitution of metal atoms in the lattice is significantly larger than that of other clay minerals. As a result, the lattice layer suffers from a lack of positive charge, and between the layers to compensate for it, Na⁺, Ca²⁺, Mg²⁺Etc. are adsorbed. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, the cation between layers is Li⁺, Na⁺In such a case, since the ionic radius is small, the bond between the layered crystal lattices is weak, and the water swells greatly with water. If shear is applied in this state, it will be easily cleaved to form a stable sol in water. Bentonite and swellable synthetic mica have a strong tendency and are preferable for the purpose of the present invention, and water swellable mica is particularly preferable.
[0034]
As water-swellable mica, Na Tetrachic Mica NaMg_2.5(Si₄O₁₀) F₂Na, Li Teniolite (NaLi) Mg₂(Si₄O₁₀) F₂Na or Li hectorite (NaLi) / 3Mg₂/ 3Li_1/3Si₄O₁₀) F₂Etc.
[0035]
The water-swellable mica preferably used in the present invention has a thickness in the range of 1 to 50 nm and a surface size in the range of 1 to 20 μm. For diffusion control, the thinner the better, the better the plane size, so long as it does not deteriorate the smoothness and transparency of the coated surface. Accordingly, the aspect ratio is preferably 100 or more, more preferably 200 or more, and further preferably 500 or more.
[0036]
The mass ratio (x1 / y1) between the mass of PVA contained in the undercoat layer (x1) and the mass of the water-swellable mica (y1) is preferably in the range of 2-10, and in the range of 5-10. More preferably. When the mass ratio is in the range of 2 to 10, the effect of suppressing oxygen permeation is great. Moreover, the coating amount of the PVA is 1 m²It is preferably 0.5 g or more per unit, and more preferably 0.8 g or more. The coating amount is 1m²By setting it to 0.5 g or more per unit, a sufficient gas permeation suppressing effect can be exhibited. The upper limit of the coating amount is 1 m²It is preferably 2.0 g or less per unit, and more preferably 1.5 g or less. The coating amount is 1m²By setting the amount to 2.0 g or less, it is possible to sufficiently secure the sensitivity and Dmax (solid image density) of the recording material. The coating amount of the water-swellable mica is 0.20 g / m for suppressing oxygen permeation.²It is preferable that it is above, and what can be derived from the coating amount of the PVA and the mass ratio of the PVA is preferable.
[0037]
The undercoat layer is a known coating such as a blade coating method or a spray coating method in which a coating solution obtained by dissolving or dispersing the PVA, bismuth oxychloride and a hardener, and, if necessary, a layered inorganic compound and other components is used. It can form by apply | coating to the support surface by a method, and drying. In addition, it is preferable that solid content concentration of a coating liquid is the range of 5-25 mass% from viewpoints, such as forming a uniform film | membrane.
[0038]
The thickness of the undercoat layer is preferably in the range of 0.5 μm to 2.5 μm, and more preferably in the range of 0.5 μm to 2.0 μm. By making the film thickness within the range of 0.5 μm to 2.5 μm, the gas permeation suppressing effect and Dmax are sufficient, and the uniformity of the coating film can be ensured, which can contribute to higher image quality. .
[0039]
(Support)
The support used for the recording material of the present invention has a layer formed by coating both surfaces of a paper substrate with a resin. As the paper substrate used for the support, natural pulp paper mainly composed of normal natural pulp, mixed paper composed of natural pulp and synthetic fiber, synthetic fiber paper mainly composed of synthetic fiber, polystyrene, Any of so-called synthetic papers obtained by pseudo-making a synthetic resin film such as polyethylene terephthalate or polypropylene may be used, but natural pulp paper (hereinafter also simply referred to as “base paper” or “paper substrate”) is particularly preferably used. The base paper may be neutral paper (pH 5-9) or acidic paper, but neutral paper is preferred.
[0040]
The base paper is mainly made of natural pulp selected from conifers, hardwoods, etc., if necessary, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, alkyl ketene dimer, higher fatty acid, epoxidized fatty acid amide, A sizing agent such as paraffin wax and alkenyl succinic acid, a starch, a polyamide polyamine epichlorohydrin, a paper strength enhancer such as polyacrylamide, a fixing agent such as a sulfuric acid band and a cationic polymer can be used. Moreover, you may add softening agents, such as surfactant. Further, as the paper support, synthetic paper using synthetic pulp instead of the natural pulp may be used, or a mixture of natural pulp and synthetic pulp in an arbitrary ratio may be used. Among them, it is preferable to use hardwood pulp having short fibers and high smoothness. The water content of the pulp material used is preferably in the range of 200 to 500 ml (C.S.F), and more preferably in the range of 300 to 400 ml.
[0041]
The paper base material may contain other components. Examples of other components include a sizing agent, a softening agent, a paper strength agent, and a fixing agent. Examples of the sizing agent include rosin, paraffin wax, higher fatty acid salt, alkenyl succinate, fatty acid anhydride, styrene maleic anhydride copolymer, alkyl ketene dimer, epoxidized fatty acid amide and the like. Examples of the softening agent include a reaction product of a maleic anhydride copolymer and a polyalkylene polyamine, a quaternary ammonium salt of a higher fatty acid, and the like. Examples of the paper strength agent include polyacrylamide, starch, polyvinyl alcohol, melamine formaldehyde condensate, gelatin and the like. Examples of the fixing agent include a sulfuric acid band and a polyamide polyamine epichlorohydrin. In addition, dyes, fluorescent dyes, antistatic agents and the like can be added as necessary.
[0042]
The support having a polyolefin resin layer on the surface is preferably a support obtained by laminating both surfaces of a base paper (paper base material) with a polyolefin resin. When the paper base is coated with the resin layer, it is preferable to subject the paper base to activation treatment such as corona discharge treatment, flame treatment, glow discharge treatment, and plasma treatment. The polyolefin resin layer may be a single layer or a multilayer. Moreover, in the case of a multilayer, the laminated body comprised from the combination of the layer which consists of polyolefin resin may be sufficient. It is preferable to use a support obtained by laminating both surfaces of a base paper with polyolefin because the surface smoothness of the support is improved and the difference in thickness of the image area caused by the image density, so-called blisters, can be further reduced. Among the polyolefin resins, polyethylene and polypropylene are preferable, and polyethylene is more preferable.
[0043]
The layer made of polyolefin resin in the present invention is a single layer or multilayer extrusion die such as a normal laminating method, a sequential laminating method, or a foot block type, a multi-manifold type, a multi-slot type, etc. It is formed by laminating by any of the laminating methods. The shape of the die is not particularly limited, but generally a T die, a coat hanger die or the like is preferably used.
[0044]
As the laminating method, for example, it can be appropriately selected from known methods described in “New Laminating Handbook” edited by the Processing Technology Research Group, so-called dry lamination, solventless dry lamination, hot A method such as melt lamination can be employed. For example, when the layer made of the polyolefin resin is formed by dry lamination, it can be formed by applying an adhesive to one side of the polyolefin resin film, drying it if desired, and thermocompression bonding to the surface of the base paper. it can. Examples of the adhesive include solvent-type vinyl resins, acrylic resins, polyamide resins, epoxy resins, rubber resins, and urethane resins. Further, the surface and / or the back surface of the base paper may be subjected to corona discharge treatment to improve the adhesion with the layer made of polyolefin resin.
[0045]
In addition, in order to improve the adhesion between the paper substrate and the polyolefin resin layer, it can be appropriately selected from rosin derivative resin, terpene resin (for example, polymer β-pinene), coumarone-indene resin, petroleum hydrocarbon resin, and the like. A tackifier resin can be blended with the polyolefin resin. These may be used independently or may mix 2 or more types.
[0046]
Specific examples of the petroleum hydrocarbon resins include aliphatic petroleum resins, aromatic petroleum resins, dicyclopentadiene petroleum resins, copolymer petroleum resins, hydrogenated petroleum resins, and alicyclic petroleum resins. Is mentioned. The aliphatic petroleum resin preferably has 5 carbon atoms, and the aromatic petroleum resin particularly preferably has 9 carbon atoms. The compounding amount of such tackifier resin is preferably in the range of 0.5 to 60% by mass and more preferably in the range of 10 to 35% by mass with respect to the polyolefin. When the compounding amount of the tackifier resin is less than 0.5% by mass, adhesion failure occurs, and when it exceeds 60% by weight, thickness unevenness in the coating width direction occurs at the time of manufacture, particularly the end of the support becomes thick, and at the time of manufacture. Has a negative impact on the efficiency. Further, an adhesive resin that can be heat-sealed with polyolefin may be blended in the polyolefin. Examples of such adhesive resins include ionomers, ethylene-vinyl acetate copolymers (EVA), ethylene-acrylic acid copolymers, and metal salts thereof. The compounding amount of the adhesive resin is preferably in the range of 20 to 500% by mass and more preferably in the range of 50 to 200% by mass with respect to the polyolefin. In addition, you may use together the said tackifier resin and adhesive resin.
[0047]
(Recording layer)
The recording material of the present invention has at least one or more recording layers that can be colored by application of heat and / or pressure. When a recording material for forming a multicolor image is used, the recording material has two or more recording layers capable of developing colors different from each other by application of heat and / or pressure. In particular, in multi-color recording materials, since the energy provided to each recording layer has a difference in height and develops a desired color, blistering is noticeable when printing with high printing energy. The recording material of the invention can suppress the generation of blisters by suppressing the gas (water vapor) permeability of the undercoat layer, and can maintain a good image quality of multicolor images.
[0048]
The recording material of the present invention is preferably a multi-color recording material capable of forming a full-color image in which a plurality of recording layers that respectively develop colors of cyan, magenta, and yellow are formed. For the multicolor recording material, the configuration examples and the recording methods described in JP-A No. 11-34495, columns 36 to 38 can be applied to the recording material of the present invention.
[0049]
The recording layer preferably contains a color developing component that is colorless at normal temperature and normal pressure, and that develops a color reaction upon application of heat and / or pressure. Examples of the color forming component include the following combinations (a) to (r).
(A) A combination of an electron donating dye precursor and an electron accepting compound.
(B) A combination of a diazo compound and a coupling component (hereinafter sometimes referred to as “coupler compound”).
(C) A combination of an organic acid metal salt such as silver behenate or silver stearate and a reducing agent such as protocatechinic acid, spiroindane or hydroquinone.
(D) A combination of a long-chain fatty acid iron salt such as ferric stearate or ferric myristate and a phenol such as tannic acid, gallic acid or ammonium salicylate.
(E) Organic acid heavy metal salts such as nickel, cobalt, lead, copper, iron, mercury and silver salts such as acetic acid, stearic acid and palmitic acid, and alkali metals or alkaline earth such as calcium sulfide, strontium sulfide and potassium sulfide A combination of a metal sulfide or a combination of the above organic acid heavy metal salt and an organic chelating agent such as s-diphenylcarbazide or diphenylcarbazone.
[0050]
(F) A combination of a heavy metal sulfate such as a sulfate such as silver, lead, mercury or sodium and a sulfur compound such as sodium tetrathionate, sodium thiosulfate or thiourea.
(G) A combination of an aliphatic ferric salt such as ferric stearate and an aromatic polyhydroxy compound such as 3,4-hydroxytetraphenylmethane.
(H) A combination of an organic acid metal salt such as silver oxalate or mercury oxalate and an organic polyhydroxy compound such as polyhydroxy alcohol, glycerin or glycol.
(I) A combination of a ferric salt of a fatty acid such as ferric pelargonate or ferric laurate and a thiocecylcarbamide or isothiocecylcarbamide derivative.
(J) A combination of an organic acid lead salt such as lead caproate, lead pelargonate or lead behenate and a thiourea derivative such as ethylenethiourea or N-dodecylthiourea.
[0051]
(K) A combination of a higher aliphatic heavy metal salt such as ferric stearate and copper stearate and zinc dialkyldithiocarbamate.
(L) Those that form an oxazine dye such as a combination of resorcin and a nitroso compound.
(M) A combination of a formazan compound and a reducing agent and / or a metal salt.
(N) A combination of a protected dye (or leuco dye) precursor and a deprotecting agent.
(O) A combination of an oxidizing color former and an oxidizing agent.
(P) A combination of phthalonitriles and diiminoisoindolines (a combination of phthalocyanines).
(Q) A combination of isocyanates and diiminoisoindolines (a combination in which a colored pigment is formed).
(R) A combination of a pigment precursor and an acid or a base (a combination that forms a pigment).
[0052]
As the coloring component, (a) a combination of an electron donating dye precursor and an electron accepting compound and (b) a combination of a diazo compound and a coupling component are preferable.
[0053]
-Electron-donating dye precursor-
Examples of the electron donating dye precursor used in the combination (a) include phthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leucooramine compounds, rhodamine lactam compounds, triphenyl. Examples thereof include various compounds such as a methane compound, a triazene compound, a spiropyran compound, a pyridine compound, a pyrazine compound, and a fluorene compound.
[0054]
Examples of the phthalide compound include U.S. Reissued Patent No. 23,024, U.S. Pat. Nos. 3,491,111, 3,491,112, and 3,491. 116 and 3,509,174, specifically, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3, 3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,3-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide and the like.
[0055]
Examples of the fluoran compound include U.S. Pat. Nos. 3,624,107, 3,627,787, 3,641,011, and 3,462,828. No. 3,681,390, No. 3,920,510, No. 3959,571, specifically, 2- ( Dipentylamino) fluorane, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isoamyl Aminofluorane, 2-anilino-3-methyl-6-N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-a Lino-3-methyl-6-N-ethyl-N-isoptylaminofluorane, 2-anilino-6-dibutylaminofluorane, 2-anilino-3-methyl-6-N-methyl-N-tetrahydrofurfuryl Aminofluorane, 2-anilino-3-methyl-6-biperidinoaminofluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2- (3,4-dichloroanilino) -6-diethylaminofluorane Etc.
[0056]
Examples of the thiazine compounds include benzoyl leucon methylene blue and p-nitrobenzyl leucomethylene blue.
[0057]
Examples of the leucooramine compound include 4,4′-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leucooramine, N-2,4,5-trichlorophenylleucooramine and the like. It is done.
[0058]
Examples of the rhodamine lactam compounds include rhodamine-B-anilinolactam and rhodamine- (p-nitro) lactam.
[0059]
Examples of the spiropyran compound include compounds described in U.S. Pat. No. 3,971,808. Specifically, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran 3, Examples include 3′-dichloro-spiro-dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-methyl-naphtho- (3-methoxy-benzo) spiropyran, 3-propyl-spiro-dibenzopyran, and the like.
[0060]
Examples of the pyridine-based and pyrazine-based compounds are described in US Pat. Nos. 3,775,424, 3,853,869, and 4,246,318. The compound of this is mentioned.
[0061]
Examples of the fluorene compound include compounds described in JP-A No. 63-94878.
[0062]
As the dye precursors that develop cyan, magenta, and yellow, the dye precursors described in US Pat. No. 4,800,149 can be used. Further, as the electron donating dye precursor for yellow coloring dye, the dye precursors described in US Pat. No. 4,800,148 can be used, and the electron donating dye precursor for cyan coloring dye can be used. For example, dye precursors described in JP-A No. 63-53542 may be used.
[0063]
-Electron-accepting compound-
Examples of the electron-accepting compound used in the combination of the above (a) include conventionally known phenol derivatives, salicylic acid derivatives, aromatic carboxylic acid metal salts, acid clay, pentonite, novolak resins, metal-treated novolak resins, metal complexes, and the like. And an electron accepting compound. Specifically, JP-B-40-9309, JP-B-45-14039, JP-A-52-140483, JP-A-48-51010, JP-A-57-210886, JP JP-A-58-87089, JP-A-59-11286, JP-A-60-176795, JP-A-61-95988, and the like.
[0064]
Of the above, for example, phenol derivatives include 2,2′-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, 1,1′-bis (3 -Chloro-4-hydroxyphenyl) cyclohexane, 1,1'-bis (4-hydroxyphenyl) cyclohexane, 1,1'-bis (3-chloro-4-hydroxyphenyl) -2-ethylbutane, 4,4'- sec-isooctylidenediphenol, 4,4'-sec-butylidenediphenol, 4-tert-octylphenol, 4-p-methylphenylphenol, 4,4'-methylcyclohexylidenephenol, 4,4'-iso Mention may be made of pentylidenephenol, benzyl p-hydroxybenzoate, etc.
[0065]
Examples of the salicylic acid derivative include 4-pentadecylsalicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (tert-octyl) salicylic acid, 5-octadecylsalicylic acid, 5-α- (p-α -Methylbenzylphenyl) ethylsalicylic acid, 3-α-methylbenzyl-5-tert-octylsalicylic acid, 5-tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-decyloxysalicylic acid, 4-dodecyloxy Examples include salicylic acid, 4-pentadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, and the like, and zinc, aluminum, calcium, copper, lead salts, and the like thereof.
[0066]
When a combination of an electron donating dye precursor and an electron accepting compound is used as the color forming component, the electron donating dye precursor is 0.1 to 5 g / m in the recording layer.²It is preferable to make it contain in the range of 0.1-1 g / m.²It is more preferable to make it contain in the range. The amount of the electron-accepting compound used is preferably in the range of 0.5 to 20 parts, more preferably in the range of 3 to 10 parts, with respect to 1 part of the electron-donating colorless dye used. preferable. If it is less than 0.5 part, sufficient color density cannot be obtained in some cases, and if it exceeds 20 parts, the sensitivity may be lowered or the coating suitability may be deteriorated.
[0067]
-Diazo compounds-
As the diazo compound that can be used in the combination (b), it is preferable to use a compound represented by the following formula.
Ar-N₂ ⁺・ Y⁻
In the above formula, Ar represents an aromatic ring group, and Y⁻Represents an acid anion.
[0068]
In the above formula, Ar represents a substituted or unsubstituted aryl group. Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, a carbamide group, a sulfonyl group, a sulfamoyl group, a sulfonamide group, a ureido group, A halogen group, an amino group, a heterocyclic group, etc. are mentioned, and these substituents may be further substituted.
[0069]
The aryl group is preferably an aryl group having 6 to 30 carbon atoms, such as a phenyl group, 2-methylphenyl group, 2-chlorophenyl group, 2-methoxyphenyl group, 2-butoxyphenyl group. 2- (2-ethylhexyloxy) phenyl group, 2-octyloxyphenyl group, 3- (2,4-di-t-pentylphenoxyethoxy) phenyl group, 4-chlorophenyl group, 2,5-dichlorophenyl group, 2 , 4,6-trimethylphenyl group, 3-chlorophenyl group, 3-methylphenyl group, 3-methoxyphenyl group, 3-butoxyphenyl group, 3-cyanophenyl group, 3- (2-ethylhexyloxy) phenyl group, 3 , 4-dichlorophenyl group, 3,5-dichlorophenyl group, 3,4-dimethoxyphenyl group,
[0070]
3- (dibutylaminocarbonylmethoxy) phenyl group, 4-cyanophenyl group, 4-methylphenyl group, 4-methoxyphenyl group, 4-butoxyphenyl group, 4- (2-ethylhexyloxy) phenyl group, 4-benzylphenyl Group, 4-aminosulfonylphenyl group, 4-N, N-dibutylaminosulfonylphenyl group, 4-ethoxycarbonylphenyl group, 4- (2-ethylhexylcarbonyl) phenyl group, 4-fluorophenyl group, 3-acetylphenyl group 2-acetylaminophenyl group, 4- (4-chlorophenylthio) phenyl group, 4- (4-methylphenyl) thio-2,5-butoxyphenyl group, 4- (N-benzyl-N-methylamino)- And 2-dodecyloxycarbonylphenyl group. Further, these groups may be further substituted with an alkyloxy group, an alkylthio group, a substituted phenyl group, a cyano group, a substituted amino group, a halogen atom, a heterocyclic group, or the like.
[0071]
Examples of the diazo compound that can be suitably used as the color forming component include diazo compounds exemplified in paragraphs 44 to 49 of JP-A-7-276808.
[0072]
The maximum absorption wavelength λmax of the diazo compound is preferably 450 nm or less, and more preferably 290 to 440 nm. The diazo compound preferably has 12 or more carbon atoms, a solubility in water of 1% or less, and a solubility in ethyl acetate of 5% or more.
In the present invention, the diazo compounds may be used alone or in combination of two or more according to the purpose such as hue adjustment.
[0073]
-Coupler compound-
The coupler compound used in the combination of (b) above forms a dye by coupling with a diazo compound used in combination in a basic atmosphere and / or a neutral atmosphere, and for various purposes such as hue adjustment. Accordingly, a plurality of types can be used in combination. As the coupler compound, it is preferable to use a coupler such as a so-called active methylene compound having a methylene group next to a carbonyl group, a phenol derivative, or a naphthol derivative. Specifically, resorcin, phloroglucin, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene-6-sulfonic acid sodium, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid Sodium, 2-hydroxy-3-naphthalenesulfonic acid anilide, 2-hydroxy-3-naphthalenesulfonic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2-ethylhexyloxypropylamide, 2-hydroxy-3-naphthalene Sulfonic acid-2-ethylhexylamide, 5-acetamido-1-naphthol,
[0074]
1-hydroxy-8-acetamidonaphthalene-3,6-disulfonic acid sodium, 1-hydroxy-8-acetamidonaphthalene-3,6-disulfonic acid dianilide, 1,5-dihydroxynaphthalene, 2-hydroxy-3-naphthoic acid morpholino Propylamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid anilide, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-cyclopentanedione, 5- (2- n-tetradecyloxyphenyl) -1,3-cyclohexanedione, 5-phenyl-4-methoxycarbonyl-1,3-cyclohexanedione, 5- (2,5-di-n-octyloxyphenyl) -1,3 -Cyclohexanedione, N, N'-dicyclohexylbarbituric acid, , N'- di -n- dodecyl barbituric acid,
[0075]
Nn-octyl-N′-n-octadecylbarbituric acid, N-phenyl-N ′-(2,5-di-n-octyloxyphenyl) barbituric acid, N, N′-bis (octadecyloxycarbonyl) Methyl) barbituric acid, 1-phenyl-3-methyl-5-pyrazolone, 1- (2,4,6-trichlorophenyl) -3-anilino-5-pyrazolone, 1- (2,4,6-trichlorophenyl) ) -3-benzamido-5-pyrazolone, 6-hydroxy-4-methyl-3-cyano-1- (2-ethylhexyl) -2-pyridone, 2,4-bis- (benzoylacetamido) toluene, 1,3- Bis- (pivaloylacetamidomethyl) benzene, benzoylacetonitrile, thenoylacetonitrile, acetoacetanilide, benzoylaceto Lido, pivaloylacetanilide, 2-chloro-5- (Nn-butylsulfamoyl) -1-pivaloylacetamidobenzene, 1- (2-ethylhexyloxypropyl) -3-cyano-4-methyl- 6-hydroxy-1,2-dihydropyridin-2-one, 1- (dodecyloxypropyl) -3-acetyl-4-methyl-6-hydroxy-1,2-dihydropyridin-2-one, 1- (4-n -Octyloxyphenyl) -3-tert-butyl-5-aminopyrazole and the like.
[0076]
Details of the coupler compound are described in JP-A-4-201483, JP-A-7-223367, JP-A-7-223368, JP-A-7-323660, JP-A-5-278608, and JP-A-5. -297024, JP-A-6-18669, JP-A-6-18670, JP-A-7-316280, JP-A-9-216468, JP-A-9-216469, JP-A-9-319025. Reference can also be made to those described in Japanese Patent Application Laid-Open No. 10-035113, Japanese Patent Application Laid-Open No. 10-193801, Japanese Patent Application Laid-Open No. 10-264532, and the like.
[0077]
When a combination of a diazo compound and a coupler compound is used as the color forming component, the diazo compound is 0.02 to 5.0 g / m in the recording layer.²It is preferable to contain in the range of 0.05-3.0 g / m²It is more preferable to make it contain in the range. The content is 0.02 g / m²If it is less than 1, sufficient color density cannot be obtained, and 5.0 g / m.²Exceeding this is not preferable because the applicability of the coating solution deteriorates. The amount of the coupler compound used is preferably in the range of 0.5 to 20 parts, more preferably in the range of 1 to 10 parts, relative to 1 part of the diazo compound. If it is less than 0.5 part, sufficient color developability may not be obtained, and if it exceeds 20 parts, the coating suitability may be deteriorated.
[0078]
The coupler compound (along with other components added if desired) can be used by adding a water-soluble polymer and solid-dispersing it with a sand mill or the like. It can also be used. Here, the solid dispersion or emulsification method is not particularly limited, and a conventionally known method can be used. Details of these methods are described in JP-A-59-190886, JP-A-2-141279, and JP-A-7-17145.
[0079]
-Organic base-
For the purpose of promoting the coupling reaction between the diazo compound and the coupler, an organic base such as a tertiary amine, piperidine, piperazine, amidine, formamidine, pyridine, guanidine or morpholine may be used. preferable. Examples of these organic bases include N, N′-bis (3-phenoxy-2-hydroxypropyl) piperazine, N, N′-bis [3- (p-methylphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis [3- (p-methoxyphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis (3-phenylthio-2-hydroxypropyl) piperazine, N, N′-bis [3- (Β-naphthoxy) -2-hydroxypropyl] piperazine, N-3- (β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine,
[0080]
Piperazines such as 1,4-bis {[3- (N-methylpiperazino) -2-hydroxy] propyloxy} benzene; N- [3- (β-naphthoxy) -2-hydroxy] propylmorpholine, 1,4- Morpholines such as bis [(3-morpholino-2-hydroxy) propyloxy] benzene, 1,3-bis [(3-morpholino-2-hydroxy) propyloxy] benzene; N- (3-phenoxy-2-hydroxy (Propyl) piperidine, N-dodecylpiperidine, and the like; triphenylguanidine, tricyclohexylguanidine, dicyclohexylphenylguanidine, 4-hydroxybenzoic acid 2-N-methyl-N-benzylaminoethyl ester, 4-hydroxybenzoic acid 2- N, N-di-n-butylaminoethyl ester , 4- (3-N, N- dibutyl-amino propoxy) benzenesulfonamide, 4- (-2 N, N- dibutyl amino ethoxycarbonyl) phenoxyacetic acid amide; and the like.
These organic bases may be used alone or in combination of two or more.
[0081]
The organic bases are disclosed in JP 57-123086, JP 60-49991, JP 60-94381, JP 9-071048, JP 9-077729, JP It is described in Japanese Patent Publication No. 9-077737.
[0082]
Moreover, the usage-amount of the said organic base is although it does not specifically limit, It is preferable that it is the range of 1-30 mol with respect to 1 mol of diazo compounds.
[0083]
-Coloring aid-
Further, for the purpose of promoting the color development reaction, a color development aid can be added.
Examples of the coloring aid include phenol derivatives, naphthol derivatives, alkoxy-substituted benzenes, alkoxy-substituted naphthalenes, hydroxy compounds, carboxylic acid amide compounds, sulfonamide compounds, and the like.
[0084]
-Binder-
The recording layer in the invention may contain a binder together with the color forming component. The binder is generally water-soluble, and polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer. Examples include coalescence, polyacrylic acid, starch derivative casein, and gelatin. In addition, for the purpose of imparting water resistance to these binders, water resistance agents (gelling agents, crosslinking agents) are added, or emulsions of hydrophobic polymers, specifically, styrene-butadiene rubber latex, acrylic resin emulsions, etc. Can also be added. In addition, it is preferable to contain a binder in the range of 10-30 mass% by dry mass in a recording layer.
[0085]
-Others-
Anti-foaming agents, fluorescent dyes, colored dyes, inorganic pigments, waxes, higher fatty acid amides, metal soaps, UV absorbers, antioxidants, latex binders, etc. are added to the recording layer as necessary. be able to. It is also effective to add various additives used in heat-sensitive recording materials and pressure-sensitive recording materials to the recording layer or other layers. Examples of the various additives include JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, JP-A-60-287485, and JP-A-60-287486. JP, 60-287487, JP 62-146680, JP 60-287488, JP 62-22885, JP 63-89877, JP JP-A 63-88380, JP-A 63-088381, JP-A 01-239282, JP-A 04-291658, JP-A 04-291684, JP-A 05-188687, JP-A 05 JP-A-188686, JP-A No. 05-110490, JP-A No. 05-1108437, JP-A No. 05-170361, JP-A No. JP-A 63-203372, JP-A 63-224989, JP-A 63-267594, JP-A 63-182484, JP-A 60-107384, JP-A 60-107383 JP, 61-160287, JP 61-185483, JP 61-2111079, JP 63-251282, JP 63-05174, JP 48- And compounds described in Japanese Patent No. 043294 and Japanese Patent Publication No. 48-033212.
[0086]
-Microcapsules-
In order for the recording layer to develop color by application of heat and / or pressure, it is preferable to impart thermal responsiveness and / or pressure responsiveness to the coloring reaction of the coloring component. For example, by encapsulating one of the coloring components in a thermo-responsive and / or pressure-responsive macrocapsule, the coloring reaction can be made thermo-responsive and / or pressure-responsive. A conventionally known method can be used as a method for microencapsulating the coloring component. For example, US Pat. No. 2,800,547, US Pat. No. 2,800,458, a method utilizing coacervation of hydrophilic wall forming material, US Pat. No. 3,287,154, British Patent No. 990443, Japanese Patent Publication No. 38-19574, No. 42-446, No. 42-771, etc., a method by polymer precipitation described in US Pat. No. 3,418,250, US Pat. No. 3,660,304, US Pat. No. 3,796,669, a method using an isocyanate polyol wall material, a method using an isocyanate wall material described in US Pat. No. 3,914,511, US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Urea-formaldehyde system described in the description, urea formaldehyde A method using a dehydr-resorcinol-based wall forming material, a method using a wall forming material such as melamine-formaldehyde resin and hydroxybrovir cellulose described in US Pat. No. 4,025,455, Japanese Patent Publication No. 36-9168, In situ method by polymerization of monomers described in JP-A-51-9079, electrolytic dispersion cooling method described in British Patent Nos. 952807 and 965074, US Pat. No. 3,111,407, British Patent No. 930422 Examples thereof include a spray drying method described in the specification.
[0087]
As a method of microencapsulating the coloring component, one coloring component (electron-donating dye precursor in the combination of (a) above, diazo compound in the combination of (b) above) is used as a hydrophobic core serving as a capsule core. The oil phase prepared by dissolving or dispersing in an organic solvent is mixed with the water phase in which the water-soluble polymer is dissolved, emulsified and dispersed by means such as a homogenizer, and then heated to form a polymer at the oil droplet interface. It is preferable to adopt an interfacial polymerization method in which a microcapsule wall of a polymer substance is formed. According to this method, capsules having a uniform particle diameter can be formed within a short time, and a recording material excellent in raw storage can be obtained.
[0088]
The reactant that forms the polymer is added inside the oil droplet and / or outside the oil droplet. Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene-methacrylate copolymer, styrene-acrylate copolymer, and the like. Among these, polyurethane, polyurea, polyamide, polyester, and polycarbonate are preferable, and polyurethane and polyurea are particularly preferable. Two or more of the above polymer substances can be used in combination.
[0089]
Examples of the water-soluble polymer include gelatin, polyvinyl pyrrolidone, and polyvinyl alcohol. For example, when polyurethane is used as the capsule wall material, the polyvalent isocyanate and the second substance that reacts therewith to form the capsule wall (for example, polyol, polyamine) should be encapsulated in a water-soluble polymer aqueous solution (aqueous phase) or By mixing in an oily medium (oil phase), emulsifying and dispersing them, and then heating, a polymer forming reaction occurs at the oil droplet interface, and a microcapsule wall can be formed. The particle size of the microcapsules is preferably in the range of 0.1 to 1.0 μm, and more preferably in the range of 0.2 to 0.7 μm.
[0090]
Further, as another method for imparting thermal responsiveness to the color development reaction, one of the color development components (for example, a receiving compound in the combination of (a), a coupler compound in the combination of (b), hereinafter referred to as “developer”). In other cases, a heat-fusible substance having a low melting point is mixed and added to the recording layer as a eutectic material, or the low melting point compound is fused to the surface of the developer particles. The method of adding to a recording layer is mentioned. Examples of the material used as the low melting point compound include waxes. Examples of the waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and higher grades such as stearic acid amide and ethylene bisstearamide. Examples include fatty acid amides and higher fatty acid esters.
[0091]
The above-mentioned recording layer is prepared by applying a coating solution obtained by dissolving and / or dispersing the color developing component and other components such as a binder to be added as desired onto the surface of the resin layer of the support and drying it. Can be formed. As the coating method of the coating liquid, there are conventionally known coating methods such as blade coating method, air knife coating method, gravure coating method, roll coating coating method, spray coating method, dip coating method, bar coating method, and extrusion coating method. Is available.
The coating amount of the coating solution for forming the recording layer is not limited, but is 3 to 15 g / m in dry mass.²Is preferably in the range of 4 to 10 g / m.²It is more preferable to be in the range.
[0092]
In the recording material of the present invention, an intermediate layer (when two or more recording layers are provided) may be provided between recording layers as desired, and a protective layer and an ultraviolet ray (light transmittance) adjusting layer may be provided on the surface of the recording layer. The PVA, bismuth oxychloride and hardener can be added to the intermediate layer as necessary. Regarding the materials contained in each layer and examples of the arrangement of each layer, the materials and arrangement examples described in columns 39 to 60 of JP-A No. 11-34495 can be applied to the recording material of the present invention.
[0093]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%” unless otherwise specified, and “average molecular weight” and “degree of polymerization” are “weight average molecular weight” and “weight”. It represents “average degree of polymerization”.
<Example 1>
(Preparation of support)
(Preparation of support)
Wood pulp consisting of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, and 0 of cationic polyacrylamide .5 parts are added at an absolute dry weight ratio to pulp, and weighed 150 g / m with a long net paper machine.²Paper made of 1.0 g / m²The surface was sized with an absolutely dry weight of polyvinyl alcohol and adjusted to a density of 1.0 by calendering.
[0094]
After the corona discharge treatment was performed on the wire surface (back surface) of the base paper, high-density polyethylene was coated with a melt extruder so as to have a resin thickness of 35 μm to form a back surface resin layer composed of a mat surface.
[0095]
In addition, after the corona discharge treatment is performed on the felt surface (front surface) side of the base paper, low-density polyethylene containing 10 parts of anatase-type titanium dioxide and a small amount of ultramarine blue is heated to a resin thickness of 30 μm using an extruder. Coating was performed to form a surface resin layer having a glossy surface.
[0096]
(Formation of undercoat layer)
-Preparation of coating solution for undercoat-
(1) Acetoacetyl-modified polyvinyl alcohol solution
Add acetoacetyl-modified polyvinyl alcohol (saponification degree 95-97%, polymerization degree about 1000, trade name: Gohsephimer Z-210, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 12.85 parts to water 87.15 parts and add 80 The solution was stirred and dissolved at a temperature of not lower than ° C. to prepare an acetoacetyl-modified polyvinyl alcohol solution having a concentration of 12.85%.
(2) 65% bismuth oxychloride dispersion
A 65% bismuth oxychloride dispersion (trade name: Bi-Flair 84 (particle diameter: 5 to 25 μm), bismuth oxychloride / acrylic resin / isopropyl acetate = 55/10/45), manufactured by MERCK) was prepared.
(3) 1.66% surfactant solution
Ethylene oxide surfactant (C₁₂H₂₅O (CH₂CH₂O)₁₀A 1.66% (methanol-dissolved) solution of H, trade name: Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) was prepared.
(4) 4% 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] -acetamide aqueous solution
A 4% aqueous solution of 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] -acetamide was prepared.
[0097]
Add 100 parts of water and 119 parts of methanol to 100 parts of the 12.85% acetoacetyl-modified polyvinyl alcohol solution of (1), mix well, and then add 47 parts of 65% bismuth oxychloride dispersion of (2). The mixture was further stirred and mixed, and further 8 parts of the 1.66% surfactant solution of (3), 4% 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] of (4) 3 parts of aqueous acetamide solution was added. And the liquid temperature was kept at 30-40 degreeC, and the coating liquid for 12.1% of undercoat layers was obtained.
[0098]
-Formation of undercoat layer-
After the resin layer on the surface of the support is subjected to corona discharge treatment, the coating amount of the undercoat layer after drying is 2.5 g / m after drying.²The undercoat layer was formed by coating with a hatched 65 mesh gravure roll to such a thickness as follows.
[0099]
(Formation of recording layer)
[Preparation of recording layer coating solution A]
-Preparation of electron donating dye precursor capsule liquid-
As an electron-donating dye precursor, 3.0 parts of crystal violet lactone was dissolved in 20 parts of ethyl acetate, and 20 parts of alkylnaphthalene, which is a high boiling point solvent, was added and heated to mix uniformly. Next, 20 parts of xylene diisocyanate / trimethylolpropane adduct as a capsule wall agent was further added to this solution and stirred uniformly to obtain an electron donating dye precursor solution.
Separately, 54 parts of a 6% aqueous solution of gelatin was prepared, and the above electron-donating dye precursor solution was added thereto and emulsified and dispersed with a homogenizer. 68 parts of water was added to the obtained emulsified liquid and homogenized, and then the temperature was raised to 50 ° C. with stirring, and the encapsulation reaction was performed for 3 hours to obtain the target electron donating dye precursor capsule liquid. . The average particle size of the capsules was 1.6 μm.
[0100]
・ Preparation of electron-accepting compound dispersion
As an electron-accepting compound, 30 parts of bisphenol A was added to 150 parts of a 4% by weight aqueous solution of gelatin and dispersed for 24 hours with a ball mill to prepare an electron-accepting compound dispersion. The average particle size of the electron accepting compound in the dispersion was 1.2 μm.
[0101]
-Preparation of coating solution-
Next, the electron-donating dye precursor capsule liquid and the electron-accepting compound dispersion are mixed so that the mass ratio of the electron-donating dye precursor / electron-accepting compound becomes 1/2, and the target recording layer Coating liquid A was obtained.
[0102]
[Preparation of recording layer coating solution B]
-Preparation of diazonium salt compound capsule liquid b-
As a diazonium salt compound, 2.0 parts of 4- (N- (2,4-di-tert-amylphenoxy) butyryl) piperazinobenzenediazonium hexafluorophosphate is dissolved in 20 parts of ethyl acetate, and a high boiling point solvent. 20 parts of an alkylnaphthalene which is As a capsule wall agent, 15 parts of a xylene diisocyanate / trimethylolpropane adduct was further added to this solution and stirred uniformly to obtain a diazonium salt compound solution.
Separately, 54 parts of a 6% aqueous solution of gelatin was prepared, and the above diazonium salt compound solution was added thereto and emulsified and dispersed with a homogenizer. 68 parts of water was added to the resulting emulsified liquid to homogenize it, and then the temperature was raised to 40 ° C. while stirring, and the encapsulation reaction was carried out for 3 hours to obtain the desired diazonium salt compound capsule liquid b. The average particle size of the capsules was 1.1 μm.
[0103]
-Preparation of coupler emulsion b-
As coupler, 1- (2′-octylphenyl) -3-methyl-5-pyrazolone 2 parts, 1,2,3-triphenylguanidine 2 parts, 1,1- (p-hydroxyphenyl) -2-ethylhexane 2 Parts, 4,4 ′-(p-phenylenediisopropylidene) diphenol, 4 parts 2-ethylhexyl-4-hydroxybenzoate, 0.3 part tricresyl phosphate, 0.1 part diethyl maleate, and 70 1 part methanol solution of calcium dodecylbenzenesulfonate is dissolved in 10 parts of ethyl acetate, this solution is added to 80 parts of 8% gelatin aqueous solution, and emulsified and dispersed with a homogenizer for 10 minutes. A coupler emulsion b was obtained.
[0104]
-Preparation of coating solution-
Next, the diazonium salt compound capsule liquid b and the coupler emulsion liquid b were mixed so that the mass ratio of diazonium salt compound / coupler was 2/3 to obtain the target recording layer coating liquid B.
[0105]
[Preparation of recording layer coating solution C]
-Preparation of diazonium salt compound capsule liquid c-
As a diazonium salt compound, 3.0 parts of 2,5-dibutoxy-4-tolylthiobenzenediazonium hexafluorophosphate is dissolved in 20 parts of ethyl acetate, and 20 parts of alkylnaphthalene which is a high boiling point solvent is added and heated. And evenly mixed. As a capsule wall agent, 15 parts of a xylene diisocyanate / trimethylolpropane adduct was further added to this solution and stirred uniformly to obtain a diazonium salt compound solution.
Separately, 54 parts of a 6% by weight aqueous solution of gelatin was prepared, and the above diazonium salt compound solution was added thereto and emulsified and dispersed with a homogenizer. 68 parts of water was added to the obtained emulsion and the mixture was homogenized. Then, the temperature was raised to 40 ° C. with stirring, and the encapsulation reaction was carried out for 3 hours to obtain the desired diazonium salt compound capsule c. The average particle size of the capsules was 1.0 μm.
[0106]
-Preparation of coupler emulsion c-
2-chloro-5- (3- (2,4-di-tert-pentyl) phenoxypropylamino) acetoacetanilide as a coupler, 2 parts of 1,2,3-triphenylguanidine, 1,1- (p -Hydroxyphenyl) -2-ethylhexane 2 parts, 4,4 '-(p-phenylenediisopropylidene) diphenol 4 parts, 2-ethylhexyl-4-hydroxybenzoate 4 parts, tricresyl phosphate 0.3 parts, Dissolve 0.1 parts of diethyl maleate and 1 part of 70% calcium dodecylbenzenesulfonate in methanol in 10 parts of ethyl acetate, add this solution to 80 parts of 8% gelatin aqueous solution, and emulsify and disperse with a homogenizer for 10 minutes. Then, the target coupler emulsion c was obtained by removing ethyl acetate.
[0107]
-Preparation of coating solution-
Subsequently, the diazonium salt compound capsule liquid c and the coupler emulsion liquid c were mixed so that the mass ratio of diazonium salt compound / coupler was 4/5 to obtain a target recording layer coating liquid C.
[0108]
[Preparation of coating solution for adjusting light transmittance]
-Preparation of UV absorber precursor capsule liquid-
30 parts of ethyl acetate, 10 parts of [2-allyl-6- (2H-benzotriazol-2-yl) -4-tert-octylphenyl] benzenesulfonate as a UV absorber precursor, 2,5-di-t -3 parts octyl-hydroquinone, 2 parts tricresyl phosphate, 4 parts α-methylstyrene dimer were dissolved. As a capsule wall agent, 20 parts of xylene diisocyanate / trimethylolpropane adduct was further added to this solution and stirred uniformly to obtain a UV absorber precursor solution.
Separately, 200 parts of an 8% aqueous solution of itaconic acid-modified polyvinyl alcohol was prepared, and the ultraviolet absorbent precursor solution was added thereto, and the mixture was emulsified and dispersed with a homogenizer. 120 parts of water was added to the obtained emulsified liquid and the mixture was homogenized. Then, the temperature was raised to 40 ° C. with stirring, and an encapsulation reaction was performed for 3 hours to obtain a target ultraviolet absorber precursor capsule liquid. The average particle size of the capsules was 0.3 μm.
[0109]
-Preparation of coating solution-
10 parts of a 2% aqueous solution of sodium (4-nonylphenoxytrioxyethylene) butyl sulfonate was added to 100 parts of the ultraviolet absorber precursor capsule liquid to obtain a coating solution for adjusting light transmittance.
[0110]
[Preparation of coating solution for intermediate layer]
To 100 parts of a 10% gelatin aqueous solution, 2 parts of a 2% aqueous solution of sodium (4-nonylphenoxytrioxyethylene) butyl sulfonate was added to obtain a coating solution for an intermediate layer.
[0111]
[Preparation of coating solution for protective layer]
To 61 parts of 5% ethylene-modified polyvinyl alcohol aqueous solution, 2.0 parts of a 20.5% zinc stearate dispersion (Hydrin F115, manufactured by Chukyo Yushi Co., Ltd.) is added, and 2 mass (4-nonylphenoxytrioxyethylene) butyl is added. 8.4 parts of an aqueous sodium sulfonate solution, 8 parts of a fluorine-based mold release agent (ME-313, manufactured by Daikin) and 0.5 part of wheat starch were added and stirred uniformly to prepare a polyvinyl alcohol solution. .
Separately, 12.5 parts of a 20% aqueous solution of kaogros (manufactured by Shiraishi Kogyo Co., Ltd.), 1.25 parts of an aqueous solution of 10% polyvinyl alcohol (PVA105, manufactured by Kuraray Co., Ltd.), and 0.39 part of a 2% aqueous sodium dodecyl sulfonate solution The mixture was mixed and dispersed with a dynomill to prepare a pigment solution.
To 80 parts of the polyvinyl alcohol liquid, 4.4 parts of the pigment liquid was added to prepare a coating solution for a protective layer.
[0112]
[Formation of recording layer]
From the lower layer, the recording layer A, the intermediate layer, the recording layer B, the intermediate layer, the recording layer C, the light transmittance adjusting layer, the protective layer are formed on the surface of the photographic paper support on which the undercoat layer has been formed. In this order, seven layers were simultaneously applied at a coating speed of 60 m / min and dried under conditions of 30 ° C.-30% RH and 40 ° C.-30% RH, respectively, to produce a multicolor thermosensitive recording material. The solid content coating amount was 6.0 g / m for the recording layer A in order.²The intermediate layer is 3.0 g / m²Recording layer B is 6.0 g / m²The intermediate layer is 3.0 g / m²Recording layer C is 5.0 g / m²The light transmittance adjusting layer is 3.0 g / m², The protective layer is 1.5 g / m²It applied so that it might become.
[0113]
<Example 2>
In the preparation of the coating solution for the undercoat layer of Example 1, 83 parts of water, 119 parts of methanol, 47 parts of a 65% bismuth oxychloride dispersion, and 8 parts of a 1.66% surfactant solution were used. 2.5g / m²In this case, 116 parts of water, 136 parts of methanol, 2.3 parts of 65% bismuth oxychloride dispersion and 3 parts of 1.66% surfactant solution are used instead of forming an undercoat layer such that 0.9g / m²A recording material was produced in the same manner as in Example 1 except that an undercoat layer was formed so that The concentration of the undercoat coating solution used in this example was 4.0%.
[0114]
<Example 3>
In the preparation of the coating solution for the undercoat layer of Example 1, 83 parts of water, 119 parts of methanol, 47 parts of 65% bismuth oxychloride dispersion, and 8 parts of 1.66% surfactant solution were used. 2.5g / m²In this case, 376 parts of water, 336 parts of methanol, 234 parts of 65% bismuth oxychloride dispersion, and 30 parts of 1.66% surfactant solution are used, and the coating amount after drying is 3 .2g / m²A recording material was produced in the same manner as in Example 1 except that an undercoat layer was formed so that The concentration of the undercoat coating solution used in this example was 15.3%.
[0115]
<Comparative Example 1>
Example 1 except that the recording layer was formed without forming the undercoat layer after the corona discharge treatment on the coated surface side of the photographic paper support having the polyester film laminated on both sides of the base paper of Example 1. In the same manner as in Example 1, a recording material was produced.
[0116]
<Comparative Example 2>
Using 83 parts of water, 119 parts of methanol, 47 parts of 65% by weight bismuth oxychloride dispersion, 8 parts of a 1.66% surfactant, and a coating weight after drying of 2.5 g / m.²Instead of forming the undercoat layer, 118 parts of water, 136 parts of methanol, 2 parts of a 1.66% surfactant are used, and the coating weight after drying is 0.76 g / m.²A recording material was produced in the same manner as in Example 1 except that an undercoat layer was formed. The concentration of the undercoat coating solution used in this comparative example was 3.6%.
[0117]
<Evaluation>
The following evaluation tests were conducted for each of Examples 1 to 3 and Comparative Examples 1 and 2 of the multicolor thermosensitive recording material of the present invention obtained above. The test results are shown in Table 2 below.
[0118]
(1) Regular reflectance measurement of support
About the support body before laminating | stacking the recording layer in Examples 1-3 and Comparative Examples 1 and 2, the total reflectance and diffuse reflectance in 440 nm were measured with the Hitachi color analyzer 607 type | mold, and total reflectance and diffuse reflection were measured. The value of the rate was measured, and the regular reflectance was determined from the difference between the values. As a reference, if the regular reflectance is 2% or more, a sharp feeling can be given to the image after the recording layer is formed. Table 2 shows the results of regular reflectance evaluation of each recording material support.
[0119]
(2) Evaluation of powder removal from the support
About the support before laminating the recording layers in Examples 1 to 3 and Comparative Examples 1 and 2, a 900 g weight was rotated on the sample using a friction tester (HEIDON-18, manufactured by Shinto Kagaku Co., Ltd.). And the degree of powder falling on the sample surface was evaluated. The case where there was almost no powder fall was evaluated as ◯, the case where powder fall occurred slightly was evaluated as Δ, and the case where there was much powder fall was evaluated as x.
[0120]
(3) Image quality evaluation
For the recording materials of Examples 1 to 3 and Comparative Examples 1 and 2, the conditions shown in Table 1 below were set to the maximum output, and the output was sequentially decreased. For each output, a digital color printer (trade name NC370D, Fuji Photo Film) A variety of images recorded using a printer were printed, and the image quality was visually evaluated by paying particular attention to the thin line portion.
The evaluation criteria are a clearer and deeper level compared to the thin line portion of the comparative print sample (Thermo-Autochrome Paper RA5-G100, manufactured by Fuji Photo Film Co., Ltd.), an equivalent level as △, and an inferior level as × Table 2 shows the image quality evaluation results of each recording material.
[0121]
[Table 1]

[0122]
(4) Evaluation of background light resistance
The recording materials of Examples 1 to 3 and Comparative Examples 1 and 2 were fixed by exposure for 15 seconds under an ultraviolet lamp having an emission center wavelength of 365 nm, and then 0.9 W using WEATHEROMETER CI 65 (manufactured by ATLAS ELECTRIC DEVICES CO.). / M²For 120 hours. Samples before and after the irradiation treatment were measured with an X-rite reflection densitometer (yellow component), and the difference (ΔDmin) was determined and evaluated. Table 2 shows the results of evaluating the background light resistance of each recording material.
[0123]
[Table 2]

[0124]
From the results in Table 2, the recording materials of Examples 1 to 3 have a higher regular reflectance than Comparative Examples 1 and 2, and an impact is generated by obtaining a feeling of brightness and a feeling of depth, and the sharpness and sharpness are high. An image was obtained. In addition, the recording materials of Examples 1 to 3 also had good background light resistance.
[0125]
【The invention's effect】
According to the present invention, sharpness (resolution) and brightness (brightness) are improved by imparting a characteristic whiteness to a white background portion, thereby forming an image with a sense of depth, and having a background light fastness. An improved heat and pressure sensitive recording material can be provided.

Claims (7)

A recording material having a recording layer capable of color development by application of heat and / or pressure on a support, comprising polyvinyl alcohol, bismuth oxychloride and a hardener on the recording layer side of the support. A recording material comprising at least one layer. 2. The recording material according to claim 1, wherein the support is formed by coating a polyolefin resin on both sides of a paper substrate. 3. The recording material according to claim 1, wherein the main particle size of the bismuth oxychloride is 5 to 25 [mu] m and the average thickness is 100 to 250 nm. The mass ratio (x / y) between the bismuth oxychloride (x) and the polyvinyl alcohol (y) is 0.1 or more and 10 or less, according to any one of claims 1 to 3. Recording material. The recording material according to claim 1, wherein the polyvinyl alcohol is acetoacetyl-modified polyvinyl alcohol having a polymerization degree of 1000 or more. The hardener is a compound having two or more vinyl groups adjacent to a substituent having a positive Hammett σ _p value in a single molecule. The recording material described. The recording material according to claim 1, wherein the recording layer includes a plurality of layers that develop yellow, magenta, or cyan.