JP2004070234A - Heat developable photosensitive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material having high sensitivity and capable of improving optical image preservability after processing. <P>SOLUTION: The heat developable photosensitive material comprises at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for a silver ion and a binder on one face of a support, wherein the photosensitive silver halide has a silver iodide content of 40-100 mol% and contains at least one metal selected from the following first group and at least one metal selected from the following second group; the first group consists of iridium, ruthenium, iron, osmium and copper, the second group consists of ruthenium, iron, osmium, rhenium, gold, platinum, copper, indium, gallium, lead, thallium, chromium, palladium, nickel and zinc, with the proviso that the metal selected from the first group and the metal selected from the second group are not identical with each other. <P>COPYRIGHT: (C)2004,JPO

Description

【００６６】
一般式（Ｒ）においては、Ｒ^１１およびＲ^１１’は各々独立に炭素数１〜２０のアルキル基を表す。Ｒ^１２およびＲ^１２’は各々独立に水素原子またはベンゼン環に置換可能な置換基を表す。Ｌは−Ｓ−基または−ＣＨＲ^１３−基を表す。Ｒ^１３は水素原子または炭素数１〜２０のアルキル基を表す。Ｘ^１およびＸ^１’は各々独立に水素原子またはベンゼン環に置換可能な基を表す。
【００６７】
各置換基について詳細に説明する。
１）Ｒ^１１およびＲ^１１’
Ｒ^１１およびＲ^１１’は各々独立に置換または無置換の炭素数１〜２０のアルキル基であり、アルキル基の置換基は特に限定されることはないが、好ましくは、アリール基、ヒドロキシ基、アルコキシ基、アリールオキシ基、アルキルチオ基、アリールチオ基、アシルアミノ基、スルホンアミド基、スルホニル基、ホスホリル基、アシル基、カルバモイル基、エステル基、ハロゲン原子等があげられる。
【００６８】
２）Ｒ^１２およびＲ^１２’、Ｘ^１およびＸ^１’
Ｒ^１２およびＲ^１２’は各々独立に水素原子またはベンゼン環に置換可能な基を表す。
Ｘ^１およびＸ^１’は、各々独立に水素原子またはベンゼン環に置換可能な基を表す。それぞれベンゼン環に置換可能な基としては、好ましくはアルキル基、アリール基、ハロゲン原子、アルコキシ基、アシルアミノ基があげられる。
【００６９】
３）Ｌ
Ｌは−Ｓ−基または−ＣＨＲ^１３−基を表す。Ｒ^１３は水素原子または炭素数１〜２０のアルキル基を表し、アルキル基は置換基を有していてもよい。
Ｒ^１３の無置換のアルキル基の具体例はメチル基、エチル基、プロピル基、ブチル基、ヘプチル基、ウンデシル基、イソプロピル基、１−エチルペンチル基、２，４，４−トリメチルペンチル基などがあげられる。
【００７０】
アルキル基の置換基の例はＲ^１１の置換基と同様で、ハロゲン原子、アルコキシ基、アルキルチオ基、アリールオキシ基、アリールチオ基、アシルアミノ基、スルホンアミド基、スルホニル基、ホスホリル基、オキシカルボニル基、カルバモイル基、スルファモイル基などがあげられる。
【００７１】
４）好ましい置換基
Ｒ^１１およびＲ^１１’として好ましくは炭素数３〜１５の２級または３級のアルキル基であり、具体的にはイソプロピル基、イソブチル基、ｔ−ブチル基、ｔ−アミル基、ｔ−オクチル基、シクロヘキシル基、シクロペンチル基、１−メチルシクロヘキシル基、１−メチルシクロプロピル基などがあげられる。Ｒ^１１およびＲ^１１’としてより好ましくは炭素数４〜１２の３級アルキル基で、その中でもｔ−ブチル基、ｔ−アミル基、１−メチルシクロヘキシル基が更に好ましく、ｔ−ブチル基が最も好ましい。
【００７２】
Ｒ^１２およびＲ^１２’として好ましくは炭素数１〜２０のアルキル基であり、具体的にはメチル基、エチル基、プロピル基、ブチル基、イソプロピル基、ｔ−ブチル基、ｔ−アミル基、シクロヘキシル基、１−メチルシクロヘキシル基、ベンジル基、メトキシメチル基、メトキシエチル基などがあげられる。より好ましくはメチル基、エチル基、プロピル基、イソプロピル基、ｔ−ブチル基である。
【００７３】
Ｘ^１およびＸ^１’は、好ましくは水素原子、ハロゲン原子、アルキル基で、より好ましくは水素原子である。
【００７４】
Ｌは好ましくは−ＣＨＲ^１３−基である。
【００７５】
Ｒ^１３として好ましくは水素原子または炭素数１〜１５のアルキル基であり、アルキル基としてはメチル基、エチル基、プロピル基、イソプロピル基、２，４，４−トリメチルペンチル基が好ましい。Ｒ^１３として特に好ましいのは水素原子、メチル基、プロピル基またはイソプロピル基である。
【００７６】
Ｒ^１３が水素原子である場合、Ｒ^１２およびＲ^１２’は好ましくは炭素数２〜５のアルキル基であり、エチル基、プロピル基がより好ましく、エチル基が最も好ましい。
【００７７】
Ｒ^１３が炭素数１〜８の１級または２級のアルキル基である場合、Ｒ^１２およびＲ^１２’はメチル基が好ましい。Ｒ^１３の炭素数１〜８の１級または２級のアルキル基としてはメチル基、エチル基、プロピル基、イソプロピル基がより好ましく、メチル基、エチル基、プロピル基が更に好ましい。
【００７８】
Ｒ^１１、Ｒ^１１’およびＲ^１２、Ｒ^１２’とがいずれもメチル基である場合、Ｒ^１３は２級のアルキル基であることが好ましい。この場合、Ｒ^１３の２級アルキル基としてはイソプロピル基、イソブチル基、１−エチルペンチル基が好ましく、イソプロピル基がより好ましい。
【００７９】
上記還元剤は、Ｒ^１１、Ｒ^１１’およびＲ^１２およびＲ^１２’、およびＲ^１３の組合せにより、種々の熱現像性能が異なる。２種以上の還元剤を種々の混合比率で併用することによってこれらの熱現像性能を調整することができるので、目的によっては還元剤を２種類以上組み合わせて使用することが好ましい。
【００８０】
以下に本発明の一般式（Ｒ）で表される化合物の具体例を示すが、本発明はこれらに限定されるものではない。
【００８１】
【化２】

【００８２】
【化３】

【００８３】
【化４】

【００８４】
特に（Ｒ−１）〜（Ｒ−２０）に示すような化合物であることが好ましい。
【００８５】
本発明において還元剤の添加量は０．０１〜５．０ｇ／ｍ^２であることが好ましく、０．１〜３．０ｇ／ｍ^２であることがより好ましく、画像形成層を有する面の銀１モルに対しては５〜５０％モル含まれることが好ましく、１０〜４０モル％で含まれることがさらに好ましい。
【００８６】
本発明の還元剤は、有機銀塩、および感光性ハロゲン化銀を含む画像形成層、およびその隣接層に添加することができるが、画像形成層に含有させることがより好ましい。
【００８７】
本発明の還元剤は溶液形態、乳化分散形態、固体微粒子分散物形態など、いかなる方法で塗布液に含有せしめ、感光材料に含有させてもよい。
【００８８】
よく知られている乳化分散法としては、ジブチルフタレート、トリクレジルフォスフェート、グリセリルトリアセテートあるいはジエチルフタレートなどのオイル、酢酸エチルやシクロヘキサノンなどの補助溶媒を用いて溶解し、機械的に乳化分散物を作製する方法が挙げられる。
【００８９】
また、固体微粒子分散法としては、還元剤を水等の適当な溶媒中にボールミル、コロイドミル、振動ボールミル、サンドミル、ジェットミル、ローラーミルあるいは超音波によって分散し、固体分散物を作成する方法が挙げられる。好ましくは、サンドミルを使った分散方法である。尚、その際に保護コロイド（例えば、ポリビニルアルコール）、界面活性剤（例えばトリイソプロピルナフタレンスルホン酸ナトリウム（３つのイソプロピル基の置換位置が異なるものの混合物）などのアニオン性界面活性剤）を用いてもよい。水分散物には防腐剤（例えばベンゾイソチアゾリノンナトリウム塩）を含有させることができる。
【００９０】
特に好ましいのは、還元剤の固体粒子分散法であり、平均粒子サイズ０．０１μｍ〜１０μｍ、好ましくは０．０５μｍ〜５μｍ、より好ましくは０．１μｍ〜１μｍの微粒子して添加するのが好ましい。本願においては他の固体分散物もこの範囲の粒子サイズに分散して用いるのが好ましい。
【００９１】
１−１−４．現像促進剤
本発明の熱現像感光材料では、現像促進剤として特開２０００−２６７２２２号や特開２０００−３３０２３４号等に記載の一般式（Ａ）で表されるスルホンアミドフェノール系の化合物、特開２００１−９２０７５号記載の一般式（ＩＩ）で表されるヒンダードフェノール系の化合物、特開平１０−６２８９５号や特開平１１−１５１１６号等に記載の一般式（Ｉ）、特願２００１−０７４２７８号に記載の一般式（１）で表されるヒドラジン系の化合物、特願２０００−７６２４０号に記載されている一般式（２）で表されるフェノール系またはナフトール系の化合物が好ましく用いられる。これらの現像促進剤は還元剤に対して０．１〜２０モル％の範囲で使用され、好ましくは０．５〜１０モル％の範囲で、より好ましくは１〜５モル％の範囲である。感材への導入方法は還元剤同様の方法があげられるが、特に固体分散物または乳化分散物として添加することが好ましい。乳化分散物として添加する場合、常温で固体である高沸点溶剤と低沸点の補助溶剤を使用して分散した乳化分散物として添加するか、もしくは高沸点溶剤を使用しない所謂オイルレス乳化分散物として添加することが好ましい。
【００９２】
本発明においては上記現像促進剤の中でも、特願２００１−０７４２７８号に記載の一般式（１）で表されるヒドラジン系の化合物および特願２０００−７６２４０号に記載されている一般式（２）で表されるフェノール系またはナフトール系の化合物が特に好ましい。
【００９３】
以下、本発明の現像促進剤の好ましい具体例を挙げるが、本発明はこれらに限定されるものではない。
【００９４】
【化５】

【００９５】
１−１−５．水素結合性化合物
本発明では、還元剤の芳香族性の水酸基（−ＯＨ）と水素結合を形成することが可能な基を有する非還元性の化合物を併用することが好ましい。
【００９６】
水素結合を形成しうる基としては、ホスホリル基、スルホキシド基、スルホニル基、カルボニル基、アミド基、エステル基、ウレタン基、ウレイド基、３級アミノ基、含窒素芳香族基などが挙げられる。その中でも好ましいのはホスホリル基、スルホキシド基、アミド基（但し、＞Ｎ−Ｈ基を持たず、＞Ｎ−Ｒａ（ＲａはＨ以外の置換基）のようにブロックされている。）、ウレタン基（但し、＞Ｎ−Ｈ基を持たず、＞Ｎ−Ｒａ（ＲａはＨ以外の置換基）のようにブロックされている。）、ウレイド基（但し、＞Ｎ−Ｈ基を持たず、＞Ｎ−Ｒａ（ＲａはＨ以外の置換基）のようにブロックされている。）を有する化合物である。
【００９７】
本発明で、特に好ましい水素結合性化合物は下記一般式（Ｄ）で表される化合物である。
【００９８】
一般式（Ｄ）
【化６】

【００９９】
一般式（Ｄ）においてＲ^２１ないしＲ^２３は各々独立にアルキル基、アリール基、アルコキシ基、アリールオキシ基、アミノ基またはヘテロ環基を表し、これらの基は無置換であっても置換基を有していてもよい。
【０１００】
Ｒ^２１ないしＲ^２３が置換基を有する場合の置換基としてはハロゲン原子、アルキル基、アリール基、アルコキシ基、アミノ基、アシル基、アシルアミノ基、アルキルチオ基、アリールチオ基、スルホンアミド基、アシルオキシ基、オキシカルボニル基、カルバモイル基、スルファモイル基、スルホニル基、ホスホリル基などがあげられ、置換基として好ましいのはアルキル基またはアリール基でたとえばメチル基、エチル基、イソプロピル基、ｔ−ブチル基、ｔ−オクチル基、フェニル基、４−アルコキシフェニル基、４−アシルオキシフェニル基などがあげられる。
【０１０１】
Ｒ^２１ないしＲ^２３のアルキル基としては具体的にはメチル基、エチル基、ブチル基、オクチル基、ドデシル基、イソプロピル基、ｔ−ブチル基、ｔ−アミル基、ｔ−オクチル基、シクロヘキシル基、１−メチルシクロヘキシル基、ベンジル基、フェネチル基、２−フェノキシプロピル基などがあげられる。
【０１０２】
アリール基としてはフェニル基、クレジル基、キシリル基、ナフチル基、４−ｔ−ブチルフェニル基、４−ｔ−オクチルフェニル基、４−アニシジル基、３，５−ジクロロフェニル基などが挙げられる。
【０１０３】
アルコキシ基としてはメトキシ基、エトキシ基、ブトキシ基、オクチルオキシ基、２−エチルヘキシルオキシ基、３，５，５−トリメチルヘキシルオキシ基、ドデシルオキシ基、シクロヘキシルオキシ基、４−メチルシクロヘキシルオキシ基、ベンジルオキシ基等が挙げられる。
【０１０４】
アリールオキシ基としてはフェノキシ基、クレジルオキシ基、イソプロピルフェノキシ基、４−ｔ−ブチルフェノキシ基、ナフトキシ基、ビフェニルオキシ基等が挙げられる。
【０１０５】
アミノ基としてはジメチルアミノ基、ジエチルアミノ基、ジブチルアミノ基、ジオクチルアミノ基、Ｎ−メチル−Ｎ−ヘキシルアミノ基、ジシクロヘキシルアミノ基、ジフェニルアミノ基、Ｎ−メチル−Ｎ−フェニルアミノ基等が挙げられる。
【０１０６】
Ｒ^２１ないしＲ^２３としてはアルキル基、アリール基、アルコキシ基、アリールオキシ基が好ましい。本発明の効果の点ではＲ^２１ないしＲ^２３のうち少なくとも一つ以上がアルキル基またはアリール基であることが好ましく、二つ以上がアルキル基またはアリール基であることがより好ましい。また、安価に入手する事ができるという点ではＲ^２１ないしＲ^２３が同一の基である場合が好ましい。
【０１０７】
以下に本発明における一般式（Ｄ）の化合物をはじめとする水素結合性化合物の具体例を示すが、本発明はこれらに限定されるものではない。
【０１０８】
【化７】

【０１０９】
【化８】

【０１１０】
水素結合性化合物の具体例は上述の他に特願２０００−１９２１９１号、同２０００−１９４８１１号に記載のものがあげられる。
【０１１１】
本発明の水素結合性化合物は、還元剤と同様に溶液形態、乳化分散形態、固体分散微粒子分散物形態で塗布液に含有せしめ、感光材料中で使用することができる。本発明の化合物は、溶液状態でフェノール性水酸基を有する化合物と水素結合による錯体を形成しており、還元剤と本発明の一般式（Ｄ）の化合物との組み合わせによっては錯体として結晶状態で単離することができる。
【０１１２】
このようにして単離した結晶粉体を固体分散微粒子分散物として使用することは安定した性能を得る上で特に好ましい。また、還元剤と本発明の水素結合性化合物を粉体で混合し、適当な分散剤を使って、サンドグラインダーミル等で分散時に錯形成させる方法も好ましく用いることができる。
【０１１３】
本発明の水素結合性化合物は還元剤に対して、１〜２００モル％の範囲で使用することが好ましく、より好ましくは１０〜１５０モル％の範囲で、さらに好ましくは３０〜１００モル％の範囲である。
【０１１４】
１−１−６．バインダー
本発明の有機銀塩含有層のバインダーはいかなるポリマーであってもよく、好適なバインダーは透明又は半透明で、一般に無色であり、天然樹脂やポリマー及びコポリマー、合成樹脂やポリマー及びコポリマー、その他フィルムを形成する媒体、例えば、ゼラチン類、ゴム類、ポリ（ビニルアルコール）類、ヒドロキシエチルセルロース類、セルロースアセテート類、セルロースアセテートブチレート類、ポリ（ビニルピロリドン）類、カゼイン、デンプン、ポリ（アクリル酸）類、ポリ（メチルメタクリル酸）類、ポリ（塩化ビニル）類、ポリ（メタクリル酸）類、スチレン−無水マレイン酸共重合体類、スチレン−アクリロニトリル共重合体類、スチレン−ブタジエン共重合体類、ポリ（ビニルアセタール）類（例えば、ポリ（ビニルホルマール）及びポリ（ビニルブチラール））、ポリ（エステル）類、ポリ（ウレタン）類、フェノキシ樹脂、ポリ（塩化ビニリデン）類、ポリ（エポキシド）類、ポリ（カーボネート）類、ポリ（酢酸ビニル）類、ポリ（オレフィン）類、セルロースエステル類、ポリ（アミド）類がある。バインダーは水又は有機溶媒またはエマルションから被覆形成してもよい。
【０１１５】
本発明では、有機銀塩を含有する層のバインダーのガラス転移温度は１０℃以上８０℃以下であることが好ましく、２０℃〜７０℃であることがより好ましく、２３℃以上６５℃以下であることが更に好ましい。
【０１１６】
なお、本明細書においてＴｇは下記の式で計算される。
１／Ｔｇ＝Σ（Ｘｉ／Ｔｇｉ）
【０１１７】
ここでは、ポリマーはｉ＝１からｎまでのｎ個のモノマー成分が共重合しているとする。Ｘｉはｉ番目のモノマーの重量分率（ΣＸｉ＝１）、Ｔｇｉはｉ番目のモノマーの単独重合体のガラス転移温度（絶対温度）である。ただしΣはｉ＝１からｎまでの和をとる。
尚、各モノマーの単独重合体ガラスの転移温度の値（Ｔｇｉ）はＰｏｌｙｍｅｒ　Ｈａｎｄｂｏｏｋ（３ｒｄ　Ｅｄｉｔｉｏｎ）（Ｊ．Ｂｒａｎｄｒｕｐ，　Ｅ．Ｈ．Ｉｍｍｅｒｇｕｔ著（Ｗｉｌｅｙ−Ｉｎｔｅｒｓｃｉｅｎｃｅ、１９８９））の値を採用した。
【０１１８】
バインダーとなるポリマーは単独種で用いてもよいし、必要に応じて２種以上を併用しても良い。また、ガラス転移温度が２０℃以上のものとガラス転移温度が２０℃未満のものを組み合わせて用いてもよい。Ｔｇの異なるポリマーを２種以上ブレンドして使用する場合には、その重量平均Ｔｇが上記の範囲に入ることが好ましい。
【０１１９】
本発明においては、有機銀塩含有層が溶媒の３０質量％以上が水である塗布液を用いて塗布し、乾燥して形成される場合に、さらに有機銀塩含有層のバインダーが水系溶媒（水溶媒）に可溶または分散可能である場合に、特に２５℃６０％ＲＨでの平衡含水率が２質量％以下のポリマーのラテックスからなる場合に性能が向上する。
最も好ましい形態は、イオン伝導度が２．５ｍＳ／ｃｍ以下になるように調製されたものであり、このような調製法としてポリマー合成後分離機能膜を用いて精製処理する方法が挙げられる。
【０１２０】
ここでいう前記ポリマーが可溶または分散可能である水系溶媒とは、水または水に７０質量％以下の水混和性の有機溶媒を混合したものである。
水混和性の有機溶媒としては、例えば、メチルアルコール、エチルアルコール、プロピルアルコール等のアルコール系、メチルセロソルブ、エチルセロソルブ、ブチルセロソルブ等のセロソルブ系、酢酸エチル、ジメチルホルミアミドなどを挙げることができる。
【０１２１】
また「２５℃６０％ＲＨにおける平衡含水率」とは、２５℃６０％ＲＨの雰囲気下で調湿平衡にあるポリマーの重量Ｗ１と２５℃で絶乾状態にあるポリマーの重量Ｗ０を用いて以下のように表すことができる。
２５℃６０％ＲＨにおける平衡含水率＝［（Ｗ１−Ｗ０）／Ｗ０］×１００（質量％）含水率の定義と測定法については、例えば高分子工学講座１４、高分子材料試験法（高分子学会編、地人書館）を参考にすることができる。
【０１２２】
本発明のバインダーポリマーの２５℃６０％ＲＨにおける平衡含水率は２質量％以下であることが好ましいが、より好ましくは０．０１質量％以上１．５質量％以下、さらに好ましくは０．０２質量％以上１質量％以下が望ましい。
【０１２３】
本発明のバインダーは水系溶媒に分散可能なポリマーが特に好ましい。分散状態の例としては、水不溶な疎水性ポリマーの微粒子が分散しているラテックスやポリマー分子が分子状態またはミセルを形成して分散しているものなどがあるが、いずれも好ましい。分散粒子の平均粒径は１〜５００００ｎｍ、より好ましくは５〜１０００ｎｍ程度の範囲が好ましい。分散粒子の粒径分布に関しては特に制限は無く、広い粒径分布を持つものでも単分散の粒径分布を持つものでもよい。
【０１２４】
本発明において水系溶媒に分散可能なポリマーの好ましい態様としては、アクリル系ポリマー、ポリ（エステル）類、ゴム類（例えばＳＢＲ樹脂）、ポリ（ウレタン）類、ポリ（塩化ビニル）類、ポリ（酢酸ビニル）類、ポリ（塩化ビニリデン）類、ポリ（オレフィン）類等の疎水性ポリマーを好ましく用いることができる。これらポリマーとしては直鎖のポリマーでも枝分かれしたポリマーでもまた架橋されたポリマーでもよいし、単一のモノマーが重合したいわゆるホモポリマーでもよいし、２種類以上のモノマーが重合したコポリマーでもよい。コポリマーの場合はランダムコポリマーでも、ブロックコポリマーでもよい。
【０１２５】
これらポリマーの分子量は数平均分子量で５０００〜１００００００、好ましくは１００００〜２０００００がよい。分子量が小さすぎるものは乳剤層の力学強度が不十分であり、大きすぎるものは成膜性が悪く好ましくない。
【０１２６】
好ましいポリマーラテックスの具体例としては以下のものを挙げることができる。以下では原料モノマーを用いて表し、括弧内の数値は質量％、分子量は数平均分子量である。多官能モノマーを使用した場合は架橋構造を作るため分子量の概念が適用できないので架橋性と記載し、分子量の記載を省略した。Ｔｇはガラス転移温度を表す。
【０１２７】
Ｐ−１；−ＭＭＡ（７０）−ＥＡ（２７）−ＭＡＡ（３）−のラテックス（分子量３７０００、Ｔｇ６１℃）
Ｐ−２；−ＭＭＡ（７０）−２ＥＨＡ（２０）−Ｓｔ（５）−ＡＡ（５）−のラテックス（分子量４００００、Ｔｇ５９℃）
Ｐ−３；−Ｓｔ（５０）−Ｂｕ（４７）−ＭＡＡ（３）−のラテックス（架橋性、Ｔｇ−１７℃）
Ｐ−４；−Ｓｔ（６８）−Ｂｕ（２９）−ＡＡ（３）−のラテックス（架橋性、Ｔｇ１７℃）
Ｐ−５；−Ｓｔ（７１）−Ｂｕ（２６）−ＡＡ（３）−のラテックス（架橋性，Ｔｇ２４℃）
Ｐ−６；−Ｓｔ（７０）−Ｂｕ（２７）−ＩＡ（３）−のラテックス（架橋性）
Ｐ−７；−Ｓｔ（７５）−Ｂｕ（２４）−ＡＡ（１）−のラテックス（架橋性、Ｔｇ２９℃）
Ｐ−８；−Ｓｔ（６０）−Ｂｕ（３５）−ＤＶＢ（３）−ＭＡＡ（２）−のラテックス（架橋性）
Ｐ−９；−Ｓｔ（７０）−Ｂｕ（２５）−ＤＶＢ（２）−ＡＡ（３）−のラテックス（架橋性）
Ｐ−１０；−ＶＣ（５０）−ＭＭＡ（２０）−ＥＡ（２０）−ＡＮ（５）−ＡＡ（５）−のラテックス（分子量８００００）
Ｐ−１１；−ＶＤＣ（８５）−ＭＭＡ（５）−ＥＡ（５）−ＭＡＡ（５）−のラテックス（分子量６７０００）
Ｐ−１２；−Ｅｔ（９０）−ＭＡＡ（１０）−のラテックス（分子量１２０００）
Ｐ−１３；−Ｓｔ（７０）−２ＥＨＡ（２７）−ＡＡ（３）のラテックス（分子量１３００００、Ｔｇ４３℃）
Ｐ−１４；−ＭＭＡ（６３）−ＥＡ（３５）−　ＡＡ（２）のラテックス（分子量３３０００、Ｔｇ４７℃）
Ｐ−１５；−Ｓｔ（７０．５）−Ｂｕ（２６．５）−ＡＡ（３）−のラテックス（架橋性，Ｔｇ２３℃）
Ｐ−１６；−Ｓｔ（６９．５）−Ｂｕ（２７．５）−ＡＡ（３）−のラテックス（架橋性，Ｔｇ２０．５℃）
【０１２８】
上記構造の略号は以下のモノマーを表す。ＭＭＡ；メチルメタクリレート、ＥＡ；エチルアクリレート、ＭＡＡ；メタクリル酸、２ＥＨＡ；２−エチルヘキシルアクリレート、Ｓｔ；スチレン、Ｂｕ；ブタジエン、ＡＡ；アクリル酸、ＤＶＢ；ジビニルベンゼン、ＶＣ；塩化ビニル、ＡＮ；アクリロニトリル、ＶＤＣ；塩化ビニリデン、Ｅｔ；エチレン、ＩＡ；イタコン酸。
【０１２９】
以上に記載したポリマーラテックスは市販もされていて、以下のようなポリマーが利用できる。アクリル系ポリマーの例としては、セビアンＡ−４６３５，４７１８，４６０１（以上ダイセル化学工業（株）製）、Ｎｉｐｏｌ　Ｌｘ８１１、８１４、８２１、８２０、８５７（以上日本ゼオン（株）製）など、ポリ（エステル）類の例としては、ＦＩＮＥＴＥＸ　ＥＳ６５０、６１１、６７５、８５０（以上大日本インキ化学（株）製）、ＷＤ−ｓｉｚｅ、ＷＭＳ（以上イーストマンケミカル製）など、ポリ（ウレタン）類の例としては、ＨＹＤＲＡＮ　ＡＰ１０、２０、３０、４０（以上大日本インキ化学（株）製）など、ゴム類の例としては、ＬＡＣＳＴＡＲ　７３１０Ｋ、３３０７Ｂ、４７００Ｈ、７１３２Ｃ（以上大日本インキ化学（株）製）、Ｎｉｐｏｌ　Ｌｘ４１６、４１０、４３８Ｃ、２５０７（以上日本ゼオン（株）製）など、ポリ（塩化ビニル）類の例としては、Ｇ３５１、Ｇ５７６（以上日本ゼオン（株）製）など、ポリ（塩化ビニリデン）類の例としては、Ｌ５０２、Ｌ５１３（以上旭化成工業（株）製）など、ポリ（オレフィン）類の例としては、ケミパールＳ１２０、ＳＡ１００（以上三井石油化学（株）製）などを挙げることができる。
これらのポリマーラテックスは単独で用いてもよいし、必要に応じて２種以上ブレンドしてもよい。
【０１３０】
本発明に用いられるポリマーラテックスとしては、特に、スチレン−ブタジエン共重合体のラテックスが好ましい。スチレン−ブタジエン共重合体におけるスチレンのモノマー単位とブタジエンのモノマー単位との重量比は４０：６０〜９５：５であることが好ましい。また、スチレンのモノマー単位とブタジエンのモノマー単位との共重合体に占める割合は６０〜９９質量％であることが好ましい。好ましい分子量の範囲は前記と同様である。
【０１３１】
本発明に用いることが好ましいスチレン−ブタジエン共重合体のラテックスとしては、前記のＰ−３〜Ｐ−８，１４，１５、市販品であるＬＡＣＳＴＡＲ−３３０７Ｂ、７１３２Ｃ、Ｎｉｐｏｌ　Ｌｘ４１６等が挙げられる。
【０１３２】
本発明の感光材料の有機銀塩含有層には必要に応じてゼラチン、ポリビニルアルコール、メチルセルロース、ヒドロキシプロピルセルロース、カルボキシメチルセルロースなどの親水性ポリマーを添加してもよい。
【０１３３】
これらの親水性ポリマーの添加量は有機銀塩含有層の全バインダーの３０質量％以下、より好ましくは２０質量％以下が好ましい。
【０１３４】
本発明の有機銀塩含有層（即ち、画像形成層）は、ポリマーラテックスをバインダーに用いて形成されたものが好ましい。有機銀塩含有層のバインダーの量は、全バインダー／有機銀塩の重量比が１／１０〜１０／１、更には１／５〜４／１の範囲が好ましい。
【０１３５】
また、このような有機銀塩含有層は、通常、感光性銀塩である感光性ハロゲン化銀が含有された感光性層（乳剤層）でもあり、このような場合の、全バインダー／ハロゲン化銀の重量比は４００〜５、より好ましくは２００〜１０の範囲が好ましい。
【０１３６】
本発明の画像形成層の全バインダー量は０．２〜３０ｇ／ｍ^２、より好ましくは１〜１５ｇ／ｍ^２の範囲が好ましい。本発明の画像形成層には架橋のための架橋剤、塗布性改良のための界面活性剤などを添加してもよい。
【０１３７】
本発明において感光材料の有機銀塩含有層塗布液の溶媒（ここでは簡単のため、溶媒と分散媒をあわせて溶媒と表す。）は、水を３０質量％以上含む水系溶媒が好ましい。水以外の成分としてはメチルアルコール、エチルアルコール、イソプロピルアルコール、メチルセロソルブ、エチルセロソルブ、ジメチルホルムアミド、酢酸エチルなど任意の水混和性有機溶媒を用いてよい。溶媒の水含有率は５０質量％以上がより好ましく、さらに好ましくは７０質量％以上が良い。
【０１３８】
好ましい溶媒組成の具体例を挙げると、水１００の他、水／メチルアルコール＝９０／１０、水／メチルアルコール＝７０／３０、水／メチルアルコール／ジメチルホルムアミド＝８０／１５／５、水／メチルアルコール／エチルセロソルブ＝８５／１０／５、水／メチルアルコール／イソプロピルアルコール＝８５／１０／５などがある（数値は質量％）。
【０１３９】
１−１−７．かぶり防止剤
本発明はカブリ防止剤として下記一般式（Ｈ）で表される化合物を含有するのが好ましい。
【０１４０】
一般式（Ｈ）　　　Ｑ−（Ｙ）ｎ−Ｃ（Ｚ_１）（Ｚ_２）Ｘ
【０１４１】
一般式（Ｈ）において、Ｑはアルキル基、アリール基またはヘテロ環基を表し、Ｙは２価の連結基を表し、ｎは０または１を表し、Ｚ_１およびＺ_２はハロゲン原子を表し、Ｘは水素原子または電子求引性基を表す。
【０１４２】
Ｑは好ましくはハメットの置換基定数σｐが正の値をとる電子求引性基で置換されたフェニル基を表す。ハメットの置換基定数に関しては、Ｊｏｕｒｎａｌ　ｏｆ　Ｍｅｄｉｃｉｎａｌ　Ｃｈｅｍｉｓｔｒｙ，１９７３，Ｖｏｌ．１６，Ｎｏ．１１，１２０７−１２１６　等を参考にすることができる。
【０１４３】
このような電子求引性基としては、例えばハロゲン原子（フッ素原子（σｐ値：０．０６）、塩素原子（σｐ値：０．２３）、臭素原子（σｐ値：０．２３）、ヨウ素原子（σｐ値：０．１８））、トリハロメチル基（トリブロモメチル（σｐ値：０．２９）、トリクロロメチル（σｐ値：０．３３）、トリフルオロメチル（σｐ値：０．５４））、シアノ基（σｐ値：０．６６）、ニトロ基（σｐ値：０．７８）、脂肪族・アリールもしくは複素環スルホニル基（例えば、メタンスルホニル（σｐ値：０．７２））、脂肪族・アリールもしくは複素環アシル基（例えば、アセチル（σｐ値：０．５０）、ベンゾイル（σｐ値：０．４３））、アルキニル基（例えば、Ｃ≡ＣＨ（σｐ値：０．２３））、脂肪族・アリールもしくは複素環オキシカルボニル基（例えば、メトキシカルボニル（σｐ値：０．４５）、フェノキシカルボニル（σｐ値：０．４４））、カルバモイル基（σｐ値：０．３６）、スルファモイル基（σｐ値：０．５７）、スルホキシド基、ヘテロ環基、ホスホリル基等があげられる。
σｐ値としては好ましくは０．２〜２．０の範囲で、より好ましくは０．４から１．０の範囲である。
【０１４４】
電子求引性基として好ましいのは、カルバモイル基、アルコキシカルボニル基、アルキルスルホニル基、アルキルホスホリル基、カルボキシル基、アルキルまたはアリールカルボニル基、およびアリールスルホニル基であり、特に好ましくはカルバモイル基、アルコキシカルボニル基、アルキルスルホニル基、アルキルホスホリル基であり、カルバモイル基が最も好ましい。
【０１４５】
Ｘは、好ましくは電子求引性基であり、より好ましくはハロゲン原子、脂肪族・アリールもしくは複素環スルホニル基、脂肪族・アリールもしくは複素環アシル基、脂肪族・アリールもしくは複素環オキシカルボニル基、カルバモイル基、スルファモイル基であり、特に好ましくはハロゲン原子である。
ハロゲン原子の中でも、好ましくは塩素原子、臭素原子、ヨウ素原子であり、更に好ましくは塩素原子、臭素原子であり、特に好ましくは臭素原子である。
【０１４６】
Ｙは好ましくは−Ｃ（＝Ｏ）−、−ＳＯ−または−ＳＯ_２　−を表し、より好ましくは−Ｃ（＝Ｏ）−、−ＳＯ_２　−であり、特に好ましくは−ＳＯ_２　−である。ｎは、０または１を表し、好ましくは１である。
【０１４７】
以下に本発明の一般式（Ｈ）の化合物の具体例を示すが、本発明はこれらに限定されるものではない。
【０１４８】
【化９】

【０１４９】
【化１０】

【０１５０】
本発明の一般式（Ｈ）で表される化合物は画像形成層の非感光性銀塩１モル当たり、１０^−４〜０．８モルの範囲で使用することが好ましく、より好ましくは１０^−３〜０．１モルの範囲で、さらに好ましくは５×１０^−３〜０．０５モルの範囲で使用することが好ましい。
特に、本発明のヨウ化銀含有率の高い組成のハロゲン化銀を用いた場合、十分なかぶり防止効果を得るためにはこの一般式（Ｈ）の化合物の添加量は重要であり、５×１０^−３〜０．０３モルの範囲で使用することが最も好ましい。
【０１５１】
本発明において、一般式（Ｈ）で表される化合物を感光材料に含有せしめる方法としては、前記還元剤の含有方法に記載の方法が挙げられる。
【０１５２】
一般式（Ｈ）で表される化合物の融点は２００℃以下であることが好ましく、さらに好ましくは１７０℃以下がよい。
【０１５３】
本発明に用いられるその他の有機ポリハロゲン化物として、特開平１１−６５０２１号の段落番号０１１１〜０１１２に記載の特許に開示されているものが挙げられる。特に特願平１１−８７２９７号の式（Ｐ）で表される有機ハロゲン化合物、特開平１０−３３９９３４号の一般式（ＩＩ）で表される有機ポリハロゲン化合物、特願平１１−２０５３３０号に記載の有機ポリハロゲン化合物が好ましい。
【０１５４】
１−１−８．その他のかぶり防止剤
その他のカブリ防止剤としては特開平１１−６５０２１号段落番号０１１３の水銀（ＩＩ）塩、同号段落番号０１１４の安息香酸類、特開２０００−２０６６４２号のサリチル酸誘導体、特開２０００−２２１６３４号の式（Ｓ）で表されるホルマリンスカベンジャー化合物、特開平１１−３５２６２４号の請求項９に係るトリアジン化合物、特開平６−１１７９１号の一般式（ＩＩＩ）で表される化合物、４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデン等が挙げられる。
【０１５５】
本発明に用いることのできるカブリ防止剤、安定剤および安定剤前駆体特開平１０−６２８９９号の段落番号００７０、欧州特許０８０３７６４Ａ１号の第２０頁第５７行〜第２１頁第７行に記載の特許のもの、特開平９−２８１６３７号、同９−３２９８６４号記載の化合物が挙げられる。
【０１５６】
本発明における熱現像感光材料はカブリ防止を目的としてアゾリウム塩を含有しても良い。アゾリウム塩としては、特開昭５９−１９３４４７号記載の一般式（ＸＩ）で表される化合物、特公昭５５−１２５８１号記載の化合物、特開昭６０−１５３０３９号記載の一般式（ＩＩ）で表される化合物が挙げられる。アゾリウム塩は感光材料のいかなる部位に添加しても良いが、添加層としては感光性層を有する面の層に添加することが好ましく、有機銀塩含有層に添加することがさらに好ましい。
【０１５７】
アゾリウム塩の添加時期としては塗布液調製のいかなる工程で行っても良く、有機銀塩含有層に添加する場合は有機銀塩調製時から塗布液調製時のいかなる工程でも良いが有機銀塩調製後から塗布直前が好ましい。アゾリウム塩の添加法としては粉末、溶液、微粒子分散物などいかなる方法で行っても良い。また、増感色素、還元剤、色調剤など他の添加物と混合した溶液として添加しても良い。
【０１５８】
本発明においてアゾリウム塩の添加量としてはいかなる量でも良いが、銀１モル当たり１×１０^−６モル以上２モル以下が好ましく、１×１０^−３モル以上０．５モル以下がさらに好ましい。
【０１５９】
１−１−９．その他の添加剤
１）メルカプト、ジスルフィド、およびチオン類
本発明には現像を抑制あるいは促進させ現像を制御するため、分光増感効率を向上させるため、現像前後の保存性を向上させるためなどにメルカプト化合物、ジスルフィド化合物、チオン化合物を含有させることができ、特開平１０−６２８９９号の段落番号００６７〜００６９、特開平１０−１８６５７２号の一般式（Ｉ）で表される化合物及びその具体例として段落番号００３３〜００５２、欧州特許公開第０８０３７６４Ａ１号の第２０ページ第３６〜５６行、特願平１１−２７３６７０号等に記載されている。中でもメルカプト置換複素芳香族化合物が好ましい。
【０１６０】
２）色調剤
本発明の熱現像感光材料では色調剤の添加が好ましく、色調剤については、特開平１０−６２８９９号の段落番号００５４〜００５５、欧州特許０８０３７６４Ａ１号のｐ．２１，２３行〜４８行、特開２０００−３５６３１７号や特願２０００−１８７２９８号に記載されており、特に、フタラジノン類（フタラジノン、フタラジノン誘導体もしくは金属塩；例えば４−（１−ナフチル）フタラジノン、６−クロロフタラジノン、５，７−ジメトキシフタラジノンおよび２，３−ジヒドロー１，４−フタラジンジオン）；フタラジノン類とフタル酸類（例えば、フタル酸、４−メチルフタル酸、４−ニトロフタル酸、フタル酸二アンモニウム、フタル酸ナトリウム、フタル酸カリウムおよびテトラクロロ無水フタル酸）の組み合わせ；フタラジン類（フタラジン、フタラジン誘導体もしくは金属塩；例えば４−（１−ナフチル）フタラジン、６−イソプロピルフタラジン、６−ｔ−ブチルフタラジン、６−クロロフタラジン、５．７−ジメトキシフタラジン、および２，３−ジヒドロフタラジン）が好ましく、特に、ヨウ化銀含有率の高い組成のハロゲン化銀との組み合わせにおいては、フタラジン類とフタル酸類の組み合わせが好ましい。
【０１６１】
好ましいフタラジン類の添加量としては、有機銀塩１モル当たり０．０１モル〜０．３モルであり、さらに好ましくは０．０２〜０．２モル、特に好ましくは０．０２〜０．１モルである。この添加量は、本発明のヨウ化銀含有率の高い組成のハロゲン化銀乳剤で課題である現像促進にとって重要な要因であり、適正な添加量の選択によって十分な現像性と低いかぶりの両立が可能となる。
【０１６２】
３）可塑剤、潤滑剤
本発明の感光性層に用いることのできる可塑剤および潤滑剤については特開平１１−６５０２１号段落番号０１１７に記載されている。滑り剤については特開平１１−８４５７３号段落番号００６１〜００６４や特願平１１−１０６８８１号段落番号００４９〜００６２記載されている。
【０１６３】
４）染料、顔料
本発明の感光性層には色調改良、レーザー露光時の干渉縞発生防止、イラジエーション防止の観点から各種染料や顔料（例えばＣ．Ｉ．Ｐｉｇｍｅｎｔ　Ｂｌｕｅ　６０、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ　Ｂｌｕｅ　６４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ　Ｂｌｕｅ　１５：６）を用いることができる。これらについてはＷＯ９８／３６３２２号、特開平１０−２６８４６５号、同１１−３３８０９８号等に詳細に記載されている。
【０１６４】
５）超硬調化剤
印刷製版用途に適した超硬調画像形成のためには、画像形成層に超硬調化剤を添加することが好ましい。超硬調化剤やその添加方法及び添加量については、同号公報段落番号０１１８、特開平１１−２２３８９８号公報段落番号０１３６〜０１９３、特願平１１−８７２９７号明細書の式（Ｈ）、式（１）〜（３）、式（Ａ）、（Ｂ）の化合物、特願平１１−９１６５２号明細書記載の一般式（ＩＩＩ）〜（Ｖ）の化合物（具体的化合物：化２１〜化２４）、硬調化促進剤については特開平１１−６５０２１号公報段落番号０１０２、特開平１１−２２３８９８号公報段落番号０１９４〜０１９５に記載されている。
【０１６５】
蟻酸や蟻酸塩を強いかぶらせ物質として用いるには、感光性ハロゲン化銀を含有する画像形成層を有する側に銀１モル当たり５ミリモル以下、さらには１ミリモル以下で含有させることが好ましい。
本発明の熱現像感光材料で超硬調化剤を用いる場合には五酸化二リンが水和してできる酸またはその塩を併用して用いることが好ましい。五酸化二リンが水和してできる酸またはその塩としては、メタリン酸（塩）、ピロリン酸（塩）、オルトリン酸（塩）、三リン酸（塩）、四リン酸（塩）、ヘキサメタリン酸（塩）などを挙げることができる。特に好ましく用いられる五酸化二リンが水和してできる酸またはその塩としては、オルトリン酸（塩）、ヘキサメタリン酸（塩）を挙げることができる。具体的な塩としてはオルトリン酸ナトリウム、オルトリン酸二水素ナトリウム、ヘキサメタリン酸ナトリウム、ヘキサメタリン酸アンモニウムなどが挙げられる。
五酸化二リンが水和してできる酸またはその塩の使用量（感光材料１ｍ^２あたりの塗布量）は感度やカブリなどの性能に合わせて所望の量でよいが、０．１〜５００ｍｇ／ｍ^２が好ましく、０．５〜１００ｍｇ／ｍ^２がより好ましい。
【０１６６】
１−１−１０．塗布液の調製および塗布
本発明の画像形成層塗布液の調製温度は３０℃以上６５℃以下がよく、さらに好ましい温度は３５℃以上６０℃未満、より好ましい温度は３５℃以上５５℃以下である。また、ポリマーラテックス添加直後の画像形成層塗布液の温度が３０℃以上６５℃以下で維持されることが好ましい。
【０１６７】
１−２．その他の層、および構成成分
本発明の熱現像感光材料は、画像形成層に加えて非感光性層を有することができる。非感光性層は、その配置から（ａ）画像形成層の上（支持体よりも遠い側）に設けられる表面保護層、（ｂ）複数の画像形成層の間や画像形成層と保護層の間に設けられる中間層、（ｃ）画像形成層と支持体との間に設けられる下塗り層、（ｄ）画像形成層の反対側に設けられるバック層に分類できる。
【０１６８】
また、光学フィルターとして作用する層を設けることができるが、（ａ）または（ｂ）の層として設けられる。アンチハレーション層は、（ｃ）または（ｄ）の層として感光材料に設けられる。
【０１６９】
１）表面保護層
本発明における熱現像感光材料は画像形成層の付着防止などの目的で表面保護層を設けることができる。表面保護層は単層でもよいし、複数層であってもよい。表面保護層については、特開平１１−６５０２１号段落番号０１１９〜０１２０、特願２０００−１７１９３６号に記載されている。
【０１７０】
本発明の表面保護層のバインダーとしてはゼラチンが好ましいがポリビニルアルコール（ＰＶＡ）を用いる若しくは併用することも好ましい。ゼラチンとしてはイナートゼラチン（例えば新田ゼラチン７５０）、フタル化ゼラチン（例えば新田ゼラチン８０１）など使用することができる。
【０１７１】
ＰＶＡとしては、特開２０００−１７１９３６号の段落番号０００９〜００２０に記載のものがあげられ、完全けん化物のＰＶＡ−１０５、部分けん化物のＰＶＡ−２０５，ＰＶＡ−３３５、変性ポリビニルアルコールのＭＰ−２０３（以上、クラレ（株）製の商品名）などが好ましく挙げられる。
【０１７２】
保護層（１層当たり）のポリビニルアルコール塗布量（支持体１ｍ^２当たり）としては０．３〜４．０ｇ／ｍ^２が好ましく、０．３〜２．０ｇ／ｍ^２がより好ましい。
【０１７３】
表面保護層（１層当たり）の全バインダー（水溶性ポリマー及びラテックスポリマーを含む）塗布量（支持体１ｍ^２当たり）としては０．３〜５．０ｇ／ｍ^２が好ましく、０．３〜２．０ｇ／ｍ^２がより好ましい。
【０１７４】
２）アンチハレーション層
本発明の熱現像感光材料においては、アンチハレーション層を感光性層に対して露光光源から遠い側に設けることができる。アンチハレーション層については特開平１１−６５０２１号段落番号０１２３〜０１２４、特開平１１−２２３８９８号、同９−２３０５３１号、同１０−３６６９５号、同１０−１０４７７９号、同１１−２３１４５７号、同１１−３５２６２５号、同１１−３５２６２６号等に記載されている。
【０１７５】
アンチハレーション層には、露光波長に吸収を有するアンチハレーション染料を含有する。露光波長が赤外域にある場合には赤外線吸収染料を用いればよく、その場合には可視域に吸収を有しない染料が好ましい。
【０１７６】
可視域に吸収を有する染料を用いてハレーション防止を行う場合には、画像形成後には染料の色が実質的に残らないようにすることが好ましく、熱現像の熱により消色する手段を用いることが好ましく、特に非感光性層に熱消色染料と塩基プレカーサーとを添加してアンチハレーション層として機能させることが好ましい。これらの技術については特開平１１−２３１４５７号等に記載されている。
【０１７７】
消色染料の添加量は、染料の用途により決定する。一般には、目的とする波長で測定したときの光学濃度（吸光度）が０．１を越える量で使用する。光学濃度は、０．２〜２であることが好ましい。このような光学濃度を得るための染料の使用量は、一般に０．００１〜１ｇ／ｍ^２程度である。
【０１７８】
なお、このように染料を消色すると、熱現像後の光学濃度を０．１以下に低下させることができる。二種類以上の消色染料を、熱消色型記録材料や熱現像感光材料において併用してもよい。同様に、二種類以上の塩基プレカーサーを併用してもよい。
【０１７９】
このような消色染料と塩基プレカーサーを用いる熱消色においては、特開平１１−３５２６２６号に記載のような塩基プレカーサーと混合すると融点を３℃以上降下させる物質（例えば、ジフェニルスルホン、４−クロロフェニル（フェニル）スルホン）を併用することが熱消色性等の点で好ましい。
【０１８０】
３）バック層
本発明に適用することのできるバック層については特開平１１−６５０２１号段落番号０１２８〜０１３０に記載されている。
【０１８１】
本発明においては、銀色調、画像の経時変化を改良する目的で３００〜４５０ｎｍに吸収極大を有する着色剤を添加することができる。このような着色剤は、特開昭６２−２１０４５８号、同６３−１０４０４６号、同６３−１０３２３５号、同６３−２０８８４６号、同６３−３０６４３６号、同６３−３１４５３５号、特開平０１−６１７４５号、特願平１１−２７６７５１号などに記載されている。このような着色剤は、通常、０．１ｍｇ／ｍ^２〜１ｇ／ｍ^２の範囲で添加され、添加する層としては感光性層の反対側に設けられるバック層が好ましい。
【０１８２】
４）マット剤
本発明において、搬送性改良のためにマット剤を表面保護層、およびバック層に添加することが好ましい。マット剤については、特開平１１−６５０２１号段落番号０１２６〜０１２７に記載されている。
マット剤は感光材料１ｍ^２当たりの塗布量で示した場合、好ましくは１〜４００ｍｇ／ｍ^２、より好ましくは５〜３００ｍｇ／ｍ^２である。
【０１８３】
また、乳剤面のマット度は、画像部に小さな白抜けが生じ、光漏れが発生するいわゆる星屑故障が生じなければいかようでも良いが、ベック平滑度が３０秒以上２０００秒以下が好ましく、特に４０秒以上１５００秒以下が好ましい。ベック平滑度は、日本工業規格（ＪＩＳ）Ｐ８１１９「紙および板紙のベック試験器による平滑度試験方法」およびＴＡＰＰＩ標準法Ｔ４７９により容易に求めることができる。
【０１８４】
本発明においてバック層のマット度としてはベック平滑度が１２００秒以下１０秒以上が好ましく、８００秒以下２０秒以上が好ましく、さらに好ましくは５００秒以下４０秒以上である。
【０１８５】
本発明において、マット剤は感光材料の最外表面層もしくは最外表面層として機能する層、あるいは外表面に近い層に含有されるのが好ましく、またいわゆる保護層として作用する層に含有されることが好ましい。
【０１８６】
５）ポリマーラテックス
本発明の表面保護層やバック層にポリマーラテックスを添加することができる。
このようなポリマーラテックスについては「合成樹脂エマルジョン（奥田平、稲垣寛編集、高分子刊行会発行（１９７８））」、「合成ラテックスの応用（杉村孝明、片岡靖男、鈴木聡一、笠原啓司編集、高分子刊行会発行（１９９３））」、「合成ラテックスの化学（室井宗一著、高分子刊行会発行（１９７０））」などにも記載され、具体的にはメチルメタクリレート（３３．５質量％）／エチルアクリレート（５０質量％）／メタクリル酸（１６．５質量％）コポリマーのラテックス、メチルメタクリレート（４７．５質量％）／ブタジエン（４７．５質量％）／イタコン酸（５質量％）コポリマーのラテックス、エチルアクリレート／メタクリル酸のコポリマーのラテックス、メチルメタクリレート（５８．９質量％）／２−エチルヘキシルアクリレート（２５．４質量％）／スチレン（８．６質量％）／２−ヒドロキシエチルメタクリレート（５．１質量％）／アクリル酸（２．０質量％）コポリマーのラテックス、メチルメタクリレート（６４．０質量％）／スチレン（９．０質量％）　／ブチルアクリレート（２０．０質量％）／２−ヒドロキシエチルメタクリレート（５．０質量％）／アクリル酸（２．０質量％）コポリマーのラテックスなどが挙げられる。
【０１８７】
ポリマーラテックスは、表面保護層、あるいはバック層の全バインダー（水溶性ポリマーおよびラテックスポリマーを含む）の１０質量％〜９０質量％用いるのが好ましく、特に２０質量％〜８０質量％が好ましい。
【０１８８】
６）膜面ｐＨ
本発明の熱現像感光材料は、熱現像処理前の膜面ｐＨが７．０以下であることが好ましく、さらに好ましくは６．６以下である。その下限には特に制限はないが、３程度である。最も好ましいｐＨ範囲は４〜６．２の範囲である。
【０１８９】
膜面ｐＨの調節はフタル酸誘導体などの有機酸や硫酸などの不揮発性の酸、アンモニアなどの揮発性の塩基を用いることが、膜面ｐＨを低減させるという観点から好ましい。特にアンモニアは揮発しやすく、塗布する工程や熱現像される前に除去できることから低膜面ｐＨを達成する上で好ましい。
また、水酸化ナトリウムや水酸化カリウム、水酸化リチウム等の不揮発性の塩基とアンモニアを併用することも好ましく用いられる。なお、膜面ｐＨの測定方法は、特願平１１−８７２９７号明細書の段落番号０１２３に記載されている。
【０１９０】
７）硬膜剤
本発明の感光性層、保護層、バック層など各層には硬膜剤を用いても良い。
硬膜剤の例としてはＴ．Ｈ．Ｊａｍｅｓ著”ＴＨＥ　ＴＨＥＯＲＹ　ＯＦ　ＴＨＥ　ＰＨＯＴＯＧＲＡＰＨＩＣ　ＰＲＯＣＥＳＳ　ＦＯＵＲＴＨ　ＥＤＩＴＩＯＮ”（Ｍａｃｍｉｌｌａｎ　Ｐｕｂｌｉｓｈｉｎｇ　Ｃｏ．，　Ｉｎｃ．刊、１９７７年刊）７７頁から８７頁に記載の各方法があり、クロムみょうばん、２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジンナトリウム塩、Ｎ，Ｎ−エチレンビス（ビニルスルフォンアセトアミド）、Ｎ，Ｎ−プロピレンビス（ビニルスルフォンアセトアミド）の他、同書７８頁など記載の多価金属イオン、米国特許４，２８１，０６０号、特開平６−２０８１９３号などのポリイソシアネート類、米国特許４，７９１，０４２号などのエポキシ化合物類、特開昭６２−８９０４８号などのビニルスルホン系化合物類が好ましく用いられる。
【０１９１】
硬膜剤は溶液として添加され、この溶液の保護層塗布液中への添加時期は、塗布する１８０分前から直前、好ましくは６０分前から１０秒前であるが、混合方法及び混合条件については本発明の効果が十分に現れる限りにおいては特に制限はない。
【０１９２】
具体的な混合方法としては添加流量とコーターへの送液量から計算した平均滞留時間を所望の時間となるようにしたタンクでの混合する方法やＮ．Ｈａｒｎｂｙ、Ｍ．Ｆ．Ｅｄｗａｒｄｓ、Ａ．Ｗ．Ｎｉｅｎｏｗ著、高橋幸司訳”液体混合技術”（日刊工業新聞社刊、１９８９年）の第８章等に記載されているスタチックミキサーなどを使用する方法がある。
【０１９３】
８）界面活性剤
本発明に適用できる界面活性剤については特開平１１−６５０２１号段落番号０１３２に記載されている。
本発明ではフッ素系界面活性剤を使用することが好ましい。フッ素系界面活性剤の好ましい具体例は特開平１０−１９７９８５号、特開２０００−１９６８０号、特開２０００−２１４５５４号等に記載されている化合物が挙げられる。また、特開平９−２８１６３６号記載の高分子フッ素系界面活性剤も好ましく用いられる。本発明においては、特願２０００−２０６５６０号記載のフッ素系界面活性剤の使用が特に好ましい。
【０１９４】
９）帯電防止剤
また、本発明では、公知の種々の金属酸化物あるいは導電性ポリマーなどを含む帯電防止層を有しても良い。帯電防止層は前述の下塗り層、バック層表面保護層などと兼ねても良く、また別途設けてもよい。帯電防止層については、特開平１１−６５０２１号段落番号０１３５、特開昭５６−１４３４３０号、同５６−１４３４３１号、同５８−６２６４６号、同５６−１２０５１９号、特開平１１−８４５７３号の段落番号００４０〜００５１、米国特許第５，５７５，９５７号、特開平１１−２２３８９８号の段落番号００７８〜００８４に記載の技術を適用することができる。
【０１９５】
１０）支持体
透明支持体は二軸延伸時にフィルム中に残存する内部歪みを緩和させ、熱現像処理中に発生する熱収縮歪みをなくすために、１３０〜１８５℃の温度範囲で熱処理を施したポリエステル、特にポリエチレンテレフタレートが好ましく用いられる。
【０１９６】
医療用の熱現像感光材料の場合、透明支持体は青色染料（例えば、特開平８−２４０８７７号実施例記載の染料−１）で着色されていてもよいし、無着色でもよい。
具体的な支持体の例は、特開平１１−６５０２１同号段落番号０１３４に記載されている。
【０１９７】
支持体には、特開平１１−８４５７４号の水溶性ポリエステル、同１０−１８６５６５号のスチレンブタジエン共重合体、特開２０００−３９６８４号や特願平１１−１０６８８１号段落番号００６３〜００８０の塩化ビニリデン共重合体などの下塗り技術を適用することが好ましい。
【０１９８】
１１）その他の添加剤
熱現像感光材料には、さらに、酸化防止剤、安定化剤、可塑剤、紫外線吸収剤あるいは被覆助剤を添加してもよい。特開平１１−６５０２１号段落番号０１３３の記載の溶剤を添加しても良い。各種の添加剤は、感光性層あるいは非感光性層のいずれかに添加する。それらについてＷＯ９８／３６３２２号、ＥＰ８０３７６４Ａ１号、特開平１０−１８６５６７号、同１０−１８５６８号等を参考にすることができる。
【０１９９】
１２）塗布方式
本発明における熱現像感光材料はいかなる方法で塗布されても良い。具体的には、エクストルージョンコーティング、スライドコーティング、カーテンコーティング、浸漬コーティング、ナイフコーティング、フローコーティング、または米国特許第２，６８１，２９４号に記載の種類のホッパーを用いる押出コーティングを　含む種々のコーティング操作が用いられ、Ｓｔｅｐｈｅｎ　Ｆ．　Ｋｉｓｔｌｅｒ、Ｐｅｔｅｒｔ　Ｍ．　Ｓｃｈｗｅｉｚｅｒ著”ＬＩＱＵＩＤ　ＦＩＬＭ　ＣＯＡＴＩＮＧ”（ＣＨＡＰＭＡＮ　＆　ＨＡＬＬ社刊、１９９７年）３９９頁から５３６頁記載のエクストルージョンコーティング、またはスライドコーティング好ましく用いられ、特に好ましくはスライドコーティングが用いられる。
【０２００】
スライドコーティングに使用されるスライドコーターの形状の例は同書４２７頁のＦｉｇｕｒｅ　１１ｂ．１に　ある。また、所望により同書３９９頁から５３６頁記載の方法、米国特許第２，７６１，７９１　号および英国特許第８３７，０９５号に記載の方法により２層またはそれ以上の層を同時に被覆することができる。
【０２０１】
本発明における有機銀塩含有層塗布液は、いわゆるチキソトロピー流体であることが好ましい。この技術については特開平１１−５２５０９号を参考にすることができる。
本発明における有機銀塩含有層塗布液は剪断速度０．１Ｓ^−１における粘度は４００ｍＰａ・ｓ以上１００，０００ｍＰａ・ｓ以下が好ましく、さらに好ましくは５００ｍＰａ・ｓ以上２０，０００ｍＰａ・ｓ以下である。
また、剪断速度１０００Ｓ^−１においては１ｍＰａ・ｓ以上２００ｍＰａ・ｓ以下が好まく、さらに好ましくは５ｍＰａ・ｓ以上８０ｍＰａ・ｓ以下である。
【０２０２】
本発明の熱現像感光材料は、塗布、乾燥直後に加熱処理をすることが好ましい。特に水性ラテックスをバインダーに用いた熱現像感光材料の場合、この加熱処理によって塗布膜の皮膜強度が改良され、その後の熱現像感光材料の種々の取扱いに対して寛容になり好ましい。加熱処理の温度は塗布膜の実効膜面温度で、６０℃〜１００℃の範囲が好ましく、加熱時間は、１秒〜６０秒の範囲が好ましい。より好ましい範囲は、７０℃〜９０℃、２秒〜１０秒の範囲である。本発明の好ましい加熱処理の方法は、特開２００２−１０７８７２号に記載されている。
【０２０３】
１３）包装材料
本発明の熱現像感光材料は、使用される前の保存時に写真性能の変質を防ぐため、あるいはロール状態の製品形態の場合にはカールしたり巻き癖が付くのを防ぐために、酸素透過率および／または水分透過率の低い包装材料で密閉包装するのが好ましい。酸素透過率は、２５℃で５０ｍｌ／ａｔｍ／ｍ^２・ｄａｙ以下であることが好ましく、より好ましくは１０ｍｌ／ａｔｍ／ｍ^２・ｄａｙ以下であり、さらに好ましくは１．０ｍｌ／ａｔｍ／ｍ^２・ｄａｙ以下である。水分透過率は、１０ｇ／ａｔｍ／ｍ^２・ｄａｙ以下であることが好ましく、より好ましくは５ｇ／ａｔｍ／ｍ^２・ｄａｙ以下であり、さらに好ましくは１ｇ／ａｔｍ／ｍ^２・ｄａｙ以下である。酸素透過率および／または水分透過率の低い包装材料の具体例としては、例えば特開平８−２５４７９３号、特開２０００−２０６６５３号に記載されているものを利用することができる。
【０２０４】
１４）その他の利用できる技術
本発明の熱現像感光材料に用いることのできる技術としては、ＥＰ８０３７６４Ａ１号、ＥＰ８８３０２２Ａ１号、ＷＯ９８／３６３２２号、特開昭５６−６２６４８号、同５８−６２６４４号、特開平９−４３７６６、同９−２８１６３７、同９−２９７３６７号、同９−３０４８６９号、同９−３１１４０５号、同９−３２９８６５号、同１０−１０６６９号、同１０−６２８９９号、同１０−６９０２３号、同１０−１８６５６８号、同１０−９０８２３号、同１０−１７１０６３号、同１０−１８６５６５号、同１０−１８６５６７号、同１０−１８６５６９号〜同１０−１８６５７２号、同１０−１９７９７４号、同１０−１９７９８２号、同１０−１９７９８３号、同１０−１９７９８５号〜同１０−１９７９８７号、同１０−２０７００１号、同１０−２０７００４号、同１０−２２１８０７号、同１０−２８２６０１号、同１０−２８８８２３号、同１０−２８８８２４号、同１０−３０７３６５号、同１０−３１２０３８号、同１０−３３９９３４号、同１１−７１００号、同１１−１５１０５号、同１１−２４２００号、同１１−２４２０１号、同１１−３０８３２号、同１１−８４５７４号、同１１−６５０２１号、同１１−１０９５４７号、同１１−１２５８８０号、同１１−１２９６２９号、同１１−１３３５３６号〜同１１−１３３５３９号、同１１−１３３５４２号、同１１−１３３５４３号、同１１−２２３８９８号、同１１−３５２６２７号、同１１−３０５３７７号、同１１−３０５３７８号、同１１−３０５３８４号、同１１−３０５３８０号、同１１−３１６４３５号、同１１−３２７０７６号、同１１−３３８０９６号、同１１−３３８０９８号、同１１−３３８０９９号、同１１−３４３４２０号、特願２０００−１８７２９８号、同２０００−１０２２９号、同２０００−４７３４５号、同２０００−２０６６４２号、同２０００−９８５３０号、同２０００−９８５３１号、同２０００−１１２０５９号、同２０００−１１２０６０号、同２０００−１１２１０４号、同２０００−１１２０６４号、同２０００−１７１９３６号も挙げられる。
【０２０５】
１５）カラー画像形成
多色カラー熱現像感光材料の構成は、各色についてこれらの二層の組合せを含んでよく、また、米国特許第４，７０８，９２８号に記載されているように単一層内に全ての成分を含んでいてもよい。
多色カラー熱現像感光材料の場合、各乳剤層は、一般に、米国特許第４，４６０，６８１号に記載されているように、各感光性層の間に官能性もしくは非官能性のバリアー層を使用することにより、互いに区別されて保持される。
【０２０６】
２．画像形成方法
２−１．露光
本発明の感光材料はいかなる方法で露光されても良いが、露光光源としてレーザー光が好ましい。本発明のようにヨウ化銀含有率の高いハロゲン化銀乳剤は、従来はその感度が低くて問題であった。しかし、レーザー光のような高照度で書き込むことで低感度の問題も解消され、しかもより少ないエネルギーで画像記録できることがわかった。このような強い光で短時間に書き込むことによって目標の感度を達成することができる。
【０２０７】
特に最高濃度（Ｄｍａｘ）を出すような露光量を与える場合、感光材料表面の好ましい光量は０．１Ｗ／ｍｍ^２〜１００Ｗ／ｍｍ^２である。より好ましくは０．５Ｗ／ｍｍ^２〜５０Ｗ／ｍｍ^２であり、最も好ましくは１Ｗ／ｍｍ^２〜５０Ｗ／ｍｍ^２である。
【０２０８】
本発明によるレーザー光としては、ガスレーザー（Ａｒ^＋，Ｈｅ−Ｎｅ，Ｈｅ−Ｃｄ）、ＹＡＧレーザー、色素レーザー、半導体レーザーなどが好ましい。また、半導体レーザーと第２高調波発生素子などを用いることもできる。好ましく用いられるレーザーは、熱現像感光材料の分光増感色素などの光吸収ピーク波長に対応して決まるが、赤〜赤外発光のＨｅ−Ｎｅレーザー、赤色半導体レーザー、あるいは青〜緑発光のＡｒ^＋，Ｈｅ−Ｎｅ，Ｈｅ−Ｃｄレーザー、青色半導体レーザーである。　近年、特に、ＳＨＧ（Ｓｅｃｏｎｄ　Ｈａｒｍｏｎｉｃ　Ｇｅｎｅｒａｔｏｒ）素子と半導体レーザーを一体化したモジュールや青色半導体レーザーが開発されてきて、短波長領域のレーザー出力装置がクローズアップされてきた。青色半導体レーザーは、高精細の画像記録が可能であること、記録密度の増大、かつ長寿命で安定した出力が得られることから、今後需要が拡大していくことが期待されている。レーザー光のピーク波長は、青色の３００ｎｍ〜５００ｎｍ、好ましくは４００ｎｍ〜５００ｎｍ、赤〜近赤外の６００ｎｍ〜９００ｎｍ、好ましくは６２０ｎｍ〜８５０ｎｍである。
【０２０９】
レーザー光は、高周波重畳などの方法によって縦マルチに発振していることも好ましく用いられる。
【０２１０】
２−２．熱現像
本発明の熱現像感光材料はいかなる方法で現像されても良いが、通常イメージワイズに露光した熱現像感光材料を昇温して現像される。好ましい現像温度としては８０〜２５０℃であり、さらに好ましくは１００〜１４０℃である。
現像時間としては１〜６０秒が好ましく、５〜３０秒がさらに好ましく、５〜２０秒が特に好ましい。
【０２１１】
熱現像の方式としてはプレートヒーター方式が好ましい。プレートヒーター方式による熱現像方式とは特開平１１−１３３５７２号に記載の方法が好ましく、潜像を形成した熱現像感光材料を熱現像部にて加熱手段に接触させることにより可視像を得る熱現像装置であって、前記加熱手段がプレートヒータからなり、かつ前記プレートヒータの一方の面に沿って複数個の押えローラが対向配設され、前記押えローラと前記プレートヒータとの間に前記熱現像感光材料を通過させて熱現像を行うことを特徴とする熱現像装置である。プレートヒータを２〜６段に分けて先端部については１〜１０℃程度温度を下げることが好ましい。
【０２１２】
このような方法は特開昭５４−３００３２号にも記載されており、熱現像感光材料に含有している水分や有機溶媒を系外に除外させることができ、また、急激に熱現像感光材料が加熱されることでの熱現像感光材料の支持体形状の変化を押さえることもできる。
【０２１３】
２−３．システム
露光部および熱現像部を備えた医療用レーザーイメージャーとして富士メディカルドライイメージャー−ＦＭ−ＤＰＬを挙げることができる。該システムは、Ｆｕｊｉ　Ｍｅｄｉｃａｌ　Ｒｅｖｉｅｗ　Ｎｏ．８，ｐａｇｅ３９〜５５に記載されており、それらの技術を利用することができる。また、ＤＩＣＯＭ規格に適合したネットワークシステムとして富士メディカル（株）が提案した「ＡＤ　ｎｅｔｗｏｒｋ」の中のレーザーイメージャー用の熱現像感光材料としても適用することができる。
【０２１４】
３．本発明の用途
本発明の高ヨウ化銀写真乳剤を用いた熱現像感光材料は、銀画像による黒白画像を形成し、医療診断用の熱現像感光材料、工業写真用熱現像感光材料、印刷用熱現像感光材料、ＣＯＭ用の熱現像感光材料として使用されることが好ましい。
【０２１５】
【実施例】
以下、本発明を実施例によって具体的に説明するが、本発明はこれらに限定されるものではない。
【０２１６】
実施例１．
１．ＰＥＴ支持体の作成、および下塗り
１−１．製膜
【０２１７】
テレフタル酸とエチレングリコ−ルを用い、常法に従い固有粘度ＩＶ＝０．６６　（フェノ−ル／テトラクロルエタン＝６／４（重量比）中２５℃で測定）のＰＥＴを得た。これをペレット化した後１３０℃で４時間乾燥した。その後Ｔ型ダイから押し出して急冷し、熱固定後の膜厚が１７５μｍになるような厚みの未延伸フィルムを作成した。
【０２１８】
これを、周速の異なるロ−ルを用い３．３倍に縦延伸、ついでテンタ−で４．５倍に横延伸を実施した。この時の温度はそれぞれ、１１０℃、１３０℃であった。この後、２４０℃で２０秒間熱固定後これと同じ温度で横方向に４％緩和した。この後テンタ−のチャック部をスリットした後、両端にナ−ル加工を行い、４ｋｇ／ｃｍ^２で巻き取り、厚み１７５μｍのロ−ルを得た。
【０２１９】
１−２．表面コロナ処理
ピラー社製ソリッドステートコロナ処理機６ＫＶＡモデルを用い、支持体の両面を室温下において２０ｍ／分で処理した。この時の電流、電圧の読み取り値から、支持体には０．３７５ｋＶ・Ａ・分／ｍ^２の処理がなされていることがわかった。この時の処理周波数は９．６ｋＨｚ、電極と誘電体ロ−ルのギャップクリアランスは１．６ｍｍであった。
【０２２０】
１−３．下塗り
１）下塗層塗布液の作成
処方▲１▼（感光層側下塗り層用）
高松油脂（株）製ペスレジンＡ−５２０（３０質量％溶液）　　　　　　　　　　　　　　　５９ｇ
ポリエチレングリコールモノノニルフェニルエーテル　　　　　　　　　　５．４ｇ
（平均エチレンオキシド数＝８．５）　１０質量％溶液
綜研化学（株）製　ＭＰ−１０００（ポリマー微粒子、平均粒径０．４μｍ）　　０．９１ｇ
蒸留水　　　　　　　　　　　　　　　　　　　　　　　　　　　９３５ｍｌ
【０２２１】
処方▲２▼（バック面第１層用）
スチレン−ブタジエン共重合体ラテックス　　　　　　　　　　　１５８ｇ
（固形分４０質量％、スチレン／ブタジエン重量比＝６８／３２）
２，４−ジクロロ−６−ヒドロキシ−Ｓ−トリアジンナトリウム塩
（８質量％水溶液）　　　　　　　　　　　　　　　　　　　　　２０ｇ
ラウリルベンゼンスルホン酸ナトリウムの１質量％水溶液　　　　１０ｍｌ
蒸留水　　　　　　　　　　　　　　　　　　　　　　　　　　　　８５４ｍｌ
【０２２２】
処方▲３▼（バック面側第２層用）
ＳｎＯ_２／ＳｂＯ　（９／１質量比、平均粒径０．０３８μｍ、１７質量％分散物）　８４ｇ
ゼラチン（１０質量％水溶液）　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　８９．２ｇ
信越化学（株）製　メトローズＴＣ−５（２質量％水溶液）　　　　　　　　　　　　８．６ｇ
綜研化学（株）製　ＭＰ−１０００　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　０．０１ｇ
ドデシルベンゼンスルホン酸ナトリウムの１質量％水溶液　　　　１０ｍｌ
ＮａＯＨ（１質量％）　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　６ｍｌ
プロキセル（ＩＣＩ社製）　　　　　　　　　　　　　　　　　１ｍｌ
蒸留水　　　　　　　　　　　　　　　　　　　　　　　　　８０５ｍｌ
【０２２３】
２）下塗り
上記厚さ１７５μｍの２軸延伸ポリエチレンテレフタレート支持体の両面それぞれに、上記コロナ放電処理を施した後、片面（感光性層面）に上記下塗り塗布液処方▲１▼をワイヤーバーでウエット塗布量が６．６ｍｌ／ｍ^２（片面当たり）になるように塗布して１８０℃で５分間乾燥し、ついでこの裏面（バック面）に上記下塗り塗布液処方▲２▼をワイヤーバーでウエット塗布量が５．７ｍｌ／ｍ^２になるように塗布して１８０℃で５分間乾燥し、更に裏面（バック面）に上記下塗り塗布液処方▲３▼をワイヤーバーでウエット塗布量が７．７ｍｌ／ｍ^２になるように塗布して１８０℃で６分間乾燥して下塗り支持体を作製した。
【０２２４】
２．バック層
２−１．バック層塗布液の調製
１）塩基プレカーサーの固体微粒子分散液（ａ）の調製
塩基プレカーサー化合物−１を６４ｇ、デモールＮ（商品名、花王（株））１０ｇ、ジフェニルスルホン２８ｇ、および蒸留水２２０ｍｌを加えて混合し、混合液を１／４Ｇサンドグラインダーミル（アイメックス（株）製）にてビーズ分散し、平均粒子径０．２μｍの塩基プレカーサー化合物の固体微粒子分散物（ａ）を得た。
【０２２５】
２）染料固体微粒子分散液（ａ）の調製
シアニン染料化合物―１を９．６ｇ、ｐ−ドデシルスルホン酸ナトリウム５．８ｇ、および蒸留水３０５ｍｌを混合して、混合液を１／４Ｇサンドグラインダーミル（アイメックス（株）製）にてビーズ分散し、平均粒子径０．２μｍの占領固体微粒子分散物（ａ）を得た。
【０２２６】
３）ハレーション防止層塗布液の調製
ゼラチン１７ｇ、ポリアクリルアミド９．６ｇ、上記の塩基プレカーサーの固体微粒子分散液（ａ）７０ｇ、上記の染料固体微粒子分散液（ａ）を５６ｇ、単分散ポリメチルメタクリレート微粒子（平均粒子サイズ８μｍ、粒径標準偏差０．４）１．５ｇ、ベンゾイソチアゾリノン０．０３ｇ、ポリエチレンスルホン酸ナトリウム２．２ｇ、青色染料化合物−１を０．２ｇ、黄色染料化合物−１を３．９ｇ、および水８４４ｍｌを混合して、ハレーション防止層塗布液を調製した。
【０２２７】
４）バック面保護層塗布液の調製
容器を４０℃に保温し、ゼラチン５０ｇ、ポリスチレンスルホン酸ナトリウム０．２ｇ、Ｎ、Ｎ−エチレンビス（ビニルスルホンアセトアミド）２．４ｇ、ｔ−オクチルフェノキシエトキシエタンスルホン酸ナトリウム１ｇ、ベンゾイソチアゾリノン３０ｍｇ、フッ素系界面活性剤（Ｆ−１）３７ｍｇ、フッ素系界面活性剤（Ｆ−２）０．１５ｇ、フッ素系界面活性剤（Ｆ−３）６４ｍｇ、フッ素系界面活性剤（Ｆ−４）３２ｍｇ、アクリル酸／エチルアクリレート共重合体（共重合重量比５／９５）８．８ｇ、エアロゾールＯＴ（アメリカンサイアナミド社製）０．６ｇ、流動パラフィン乳化物を流動パラフィンとして１．８ｇ、水を９５０ｍｌ混合してバック面保護層塗布液とした。
【０２２８】
２−２．バック層の塗布
上記下塗り支持体のバック面側に、ハレーション防止層塗布液を固体微粒子染料の塗布量が０．０４ｇ／ｍ^２となるように、またバック面保護層塗布液をゼラチン塗布量が１．７ｇ／ｍ^２となるように同時重層塗布し、乾燥し、バック層を作成した。
【０２２９】
３．画像形成層、中間層、および表面保護層
３−１．塗布用材料の準備
１）ハロゲン化銀乳剤
【０２３０】
（比較のハロゲン化銀乳剤Ａの調製）
蒸留水１４２０ｍｌに１質量％ヨウ化カリウム溶液４．３ｍｌを加え、さら０．５ｍｏｌ／Ｌ濃度の硫酸を３．５ｍｌ、フタル化ゼラチン３６．７ｇを添加した液をステンレス製反応壺中で攪拌しながら、３５℃に液温を保ち、硝酸銀２２．２２ｇに蒸留水を１９５．６ｍｌに希釈した溶液Ａとヨウ化カリウム２１．８ｇを蒸留水にて容量２１９ｍｌに希釈した溶液Ｂを一定流量で９分間かけて全量添加した。その後、３．５質量％の過酸化水素水溶液を１０ｍｌ添加し、さらにベンゾイミダゾールの１０質量％水溶液を１０．８ｍｌ添加した。さらに、硝酸銀５１．８６ｇに蒸留水を加えて３１７．５ｍｌに希釈した溶液Ｃとヨウ化カリウム６０ｇを蒸留水にて容量６００ｍｌに希釈した溶液Ｄを、溶液Ｃは一定流量で１２０分間かけて全量添加し、溶液ＤはｐＡｇを８．１に維持しながらコントロールドダブルジェット法で添加した。
【０２３１】
銀１モル当たり１×１０^−４モルになるよう六塩化イリジウム（ＩＩＩ）酸カリウムを溶液Ｃおよび溶液Ｄを添加しはじめてから１０分後に全量添加した。０．５ｍｏｌ／Ｌ濃度の硫酸を用いてｐＨを３．８に調整し、攪拌を止め、沈降／脱塩／水洗工程をおこなった。１ｍｏｌ／Ｌ濃度の水酸化ナトリウムを用いてｐＨ５．９に調整し、ｐＡｇ８．０のハロゲン化銀分散物を作成した。調製できたハロゲン化銀乳剤中の粒子は、平均球相当径０．０３７μｍ、球相当径の変動係数１７％の純ヨウ化銀粒子であった。粒子サイズ等は、電子顕微鏡を用い１０００個の粒子の平均から求めた。
【０２３２】
上記ハロゲン化銀分散物を攪拌しながら３８℃に維持して、０．３４質量％の１，２−ベンゾイソチアゾリン−３−オンのメタノール溶液を５ｍｌ加え、４０分後に分光増感色素Ａと増感色素Ｂのモル比で１：１のメタノール溶液を銀１モル当たり増感色素ＡとＢの合計として１．２×１０^−３モル加え、１分後に４７℃に昇温した。昇温の２０分後にベンゼンチオスルフォン酸ナトリウムをメタノール溶液で銀１モルに対して７．６×１０^−５モル加え、そのあとｐＡｇ５．５に調製したあと５分後にテルル増感剤（ビス（Ｎ―フェニル−Ｎ―メチルカルバモイル）テルリド）を５．１×１０^−４モル／モル銀を加えて８４分間熟成した。乳剤のｐＡｇを７．５に調製したあと、Ｎ，Ｎ’−ジヒドロキシ−Ｎ”−ジエチルメラミンの０．８質量％メタノール溶液１．３ｍｌを加え、さらに４分後に、５−メチル−２−メルカプトベンヅイミダゾールをメタノール溶液で銀１モル当たり４．８×１０^−３モル及び１−フェニル−２−ヘプチル−５−メルカプト−１，３，４−トリアゾールをメタノール溶液で銀１モルに対して５．４×１０^−３モル添加して、比較のハロゲン化銀乳剤Ａを作成した。
【０２３３】
（比較のハロゲン化銀乳剤Ｂの調製）
比較のハロゲン化銀乳剤Ａの調製において、六塩化イリジウム（ＩＩＩ）酸カリウムの代わりに六シアン化鉄（ＩＩ）カリウム水溶液を銀１モル当たり３×１０^−３モル全量添加して、その他は同様にして比較のハロゲン化銀乳剤Ｂを調製した。
【０２３４】
（比較のハロゲン化銀乳剤Ｃの調製）
比較のハロゲン化銀乳剤Ａの調製において、六塩化イリジウム（ＩＩＩ）酸カリウムを除いて、その他は同様にして比較のハロゲン化銀乳剤Ｃを調製した。
【０２３５】
（本発明のハロゲン化銀乳剤−１〜７の調製）
乳剤―１：Ｉｒ／Ｆｅ（Ｉｒ：均一、Ｆｅ：均一）
比較のハロゲン化銀乳剤Ａの調製において、銀１モル当たり５×１０^−４モルおよび５×１０^−３モルそれぞれ均一ト゛ーフ゜になるよう六塩化イリジウム（ＩＩＩ）酸カリウムおよび六シアン化鉄（ＩＩ）カリウム水溶液を溶液Ｃおよび溶液Ｄを添加して、その他は同様にして本発明のハロゲン化銀乳剤１を調製した。
乳剤―２：Ｉｒ／Ｆｅ（Ｉｒ：コア、Ｆｅ：シェル）
本発明のハロゲン化銀乳剤１の調製において、コア部ドープになるよう六塩化イリジウム（ＩＩＩ）酸カリウム水溶液を溶液Ｃおよび溶液Ｄの代わりに溶液Ｃのみに添加して、シェル部ドープになるよう六シアン化鉄（ＩＩ）カリウム水溶液を溶液Ｃおよび溶液Ｄの代わりに溶液Ｄのみに添加して、その他は同様にして本発明のハロゲン化銀乳剤２を調製した。
乳剤―３：Ｉｒ／Ｆｅ（Ｉｒ：コア、Ｆｅ：表面）
本発明のハロゲン化銀乳剤１の調製において、六シアン化鉄（ＩＩ）カリウム水溶液を溶液Ｃおよび溶液Ｄの代わりに粒子形成後に、粒子形成反応容器に直接添加して、その他は同様にして本発明のハロゲン化銀乳剤３を調製した。
乳剤―４：Ｒｕ／Ｆｅ（Ｒｕ：コア、Ｆｅ：表面）
本発明のハロゲン化銀乳剤３の調製において、六塩化イリジウム（ＩＩＩ）酸カリウム溶液の代わりに、ヘキサクロロルテニウム（ＩＩ）酸カリウム水溶液を銀１モル当たり５×１０^−４モルとなるように添加して、その他は同様にして本発明のハロゲン化銀乳剤４を調製した。
乳剤―５：Ｃｕ／Ｆｅ（Ｃｕ：コア、Ｆｅ：表面）
本発明のハロゲン化銀乳剤３の調製において、六塩化イリジウム（ＩＩＩ）酸カリウム溶液の代わりに、硝酸銅（ＩＩＩ）水溶液を銀１モル当たり５×１０^−４モルとなるように添加して、その他は同様にして本発明のハロゲン化銀乳剤５を調製した。
乳剤―６：Ｆｅ／Ｐｔ（Ｆｅ：コア、Ｐｔ：表面）
本発明のハロゲン化銀乳剤５の調製において、硝酸銅（ＩＩ）水溶液の代わりに、六シアン化鉄（ＩＩ）カリウム水溶液を銀１モル当たり５×１０^−３モルとなるように添加して、六シアン化鉄（ＩＩ）カリウム水溶液の代わりに、テトラクロロ白金（ＩＩ）酸カリウム水溶液を銀１モル当たり５×１０^−３モルとなるように添加して、その他は同様にして本発明のハロゲン化銀乳剤６を調製した。
乳剤―７：Ｏｓ／Ｆｅ（Ｏｓ：コア、Ｆｅ：表面）
本発明のハロゲン化銀乳剤４の調製において、ヘキサヨードルテニウム（ＩＩ）酸カリウム塩水溶液の代わりに、ヘキサクロロオスミウム（ＩＩＩ）酸カリウム水溶液を銀１モル当たり５×１０^−４モルとなるように添加して、その他は同様にして本発明のハロゲン化銀乳剤４を調製した。
【０２３６】
（塗布液添加用乳剤１ａ〜１ｃ、１〜７の調製）
上記ハロゲン化銀乳剤を小分けして溶解し、それぞれに１−（３−メチルウレイド）フェニル−５−メルカプトテトラゾールを銀１モル当たり５×１０^−３モル添加し、その後、塗布液添加用乳剤１ｋｇあたりハロゲン化銀の含有量が銀として３８．２ｇとなるように加水した。
【０２３７】
２）脂肪酸銀分散物の調製
ヘンケル社製ベヘン酸（製品名Ｅｄｅｎｏｒ　Ｃ２２−８５Ｒ）８７．６Ｋｇ、蒸留水４２３Ｌ、５ｍｏｌ／Ｌ濃度のＮａＯＨ水溶液４９．２Ｌ、ｔｅｒｔ−ブタノール１２０Ｌを混合し、７５℃にて１時間攪拌し反応させ、ベヘン酸ナトリウム溶液を得た。別に、硝酸銀４０．４ｋｇの水溶液２０６．２Ｌ（ｐＨ４．０）を用意し、１０℃にて保温した。６３５Ｌの蒸留水と３０Ｌのｔｅｒｔ−ブタノールを入れた反応容器を３０℃に保温し、十分に撹拌しながら先のベヘン酸ナトリウム溶液の全量と硝酸銀水溶液の全量を流量一定でそれぞれ９３分１５秒と９０分かけて添加した。このとき、硝酸銀水溶液添加開始後１１分間は硝酸銀水溶液のみが添加されるようにし、そのあとベヘン酸ナトリウム溶液を添加開始し、硝酸銀水溶液の添加終了後１４分１５秒間はベヘン酸ナトリウム溶液のみが添加されるようにした。このとき、反応容器内の温度は３０℃とし、液温度が一定になるように外温コントロールした。また、ベヘン酸ナトリウム溶液の添加系の配管は、２重管の外側に温水を循環させる事により保温し、添加ノズル先端の出口の液温度が７５℃になるよう調製した。また、硝酸銀水溶液の添加系の配管は、２重管の外側に冷水を循環させることにより保温した。ベヘン酸ナトリウム溶液の添加位置と硝酸銀水溶液の添加位置は撹拌軸を中心として対称的な配置とし、また反応液に接触しないような高さに調製した。
【０２３８】
ベヘン酸ナトリウム溶液を添加終了後、そのままの温度で２０分間撹拌放置し、３０分かけて３５℃に昇温し、その後２１０分熟成を行った。熟成終了後直ちに、遠心濾過で固形分を濾別し、固形分を濾過水の伝導度が３０μＳ／ｃｍになるまで水洗した。こうして脂肪酸銀塩を得た。得られた固形分は、乾燥させないでウエットケーキとして保管した。
【０２３９】
得られたベヘン酸銀粒子の形態を電子顕微鏡撮影により評価したところ、平均値でａ＝０．１４μｍ、ｂ＝０．４μｍ、ｃ＝０．６μｍ、平均アスペクト比５．２、平均球相当径０．５２μｍ、球相当径の変動係数１５％のりん片状の結晶であった。（ａ，ｂ，ｃは本文の規定）
【０２４０】
乾燥固形分２６０ｋｇ相当のウエットケーキに対し、ポリビニルアルコール（商品名：ＰＶＡ−２１７、クラレ（株））１９．３ｋｇおよび水を添加し、全体量を１０００ｋｇとしてからディゾルバー羽根でスラリー化し、更にパイプラインミキサー（みづほ工業製：ＰＭ−１０型）で予備分散した。
【０２４１】
次に予備分散済みの原液を分散機（商品名：マイクロフルイダイザーＭ−６１０、マイクロフルイデックス・インターナショナル・コーポレーション製、Ｚ型インタラクションチャンバー使用）の圧力を１２６０ｋｇ／ｃｍ^２に調節して、三回処理し、ベヘン酸銀分散物を得た。冷却操作は蛇管式熱交換器をインタラクションチャンバーの前後に各々装着し、冷媒の温度を調節することで１８℃の分散温度に設定した。
【０２４２】
３）還元剤分散物（ａ）の調製
還元剤錯体−１を１０ｋｇ、トリフェニルホスフィンオキシド０．１２ｋｇおよび変性ポリビニルアルコール（クラレ（株）製、ポバールＭＰ２０３）の１０質量％水溶液１６ｋｇに、水７．２ｋｇを添加して、よく混合してスラリーとした。このスラリーをダイアフラムポンプで送液し、平均直径０．５ｍｍのジルコニアビーズを充填した横型サンドミル（ＵＶＭ−２：アイメックス（株）製）にて４時間３０分分散したのち、ベンゾイソチアゾリノンナトリウム塩０．２ｇと水を加えて還元剤錯体の濃度が２５質量％になるように調製し、還元剤分散物（ａ）を得た。こうして得た分散物に含まれる還元剤錯体粒子はメジアン径０．４６μｍ、最大粒子径１．６μｍ以下であった。得られた還元剤錯体分散物は孔径３．０μｍのポリプロピレン製フィルターにてろ過を行い、ゴミ等の異物を除去して収納した。
【０２４３】
４）ポリハロゲン化合物の調製
（有機ポリハロゲン化合物分散物（ａ）の調製）
有機ポリハロゲン化合物−１を１０ｋｇと変性ポリビニルアルコールＭＰ２０３の２０質量％水溶液１０ｋｇと、トリイソプロピルナフタレンスルホン酸ナトリウムの２０質量％水溶液０．４ｋｇと、水１４ｋｇを添加して、よく混合してスラリーとした。このスラリーをダイアフラムポンプで送液し、平均直径０．５ｍｍのジルコニアビーズを充填した横型サンドミルＵＶＭ−２にて５時間分散したのち、ベンゾイソチアゾリノンナトリウム塩０．２ｇと水を加えて有機ポリハロゲン化合物の濃度が２６質量％になるように調製し、有機ポリハロゲン化合物分散物（ａ）を得た。こうして得たポリハロゲン化合物分散物に含まれる有機ポリハロゲン化合物粒子はメジアン径０．４１μｍ、最大粒子径２．０μｍ以下であった。得られた有機ポリハロゲン化合物分散物は孔径１０．０μｍのポリプロピレン製フィルターにてろ過を行い、ゴミ等の異物を除去して収納した。
【０２４４】
（有機ポリハロゲン化合物分散物（ｂ）の調製）
有機ポリハロゲン化合物−２を１０ｋｇと変性ポリビニルアルコールＭＰ２０３の１０質量％水溶液２０ｋｇと、トリイソプロピルナフタレンスルホン酸ナトリウムの２０質量％水溶液０．４ｋｇと、水８ｋｇを添加して、よく混合してスラリーとした。このスラリーをダイアフラムポンプで送液し、平均直径０．５ｍｍのジルコニアビーズを充填した横型サンドミルＵＶＭ−２にて５時間分散したのち、ベンゾイソチアゾリノンナトリウム塩０．２ｇと水を加えて有機ポリハロゲン化合物の濃度が２５質量％になるように調製した。この分散液を４０℃で５時間加温し、有機ポリハロゲン化合物−３分散物を得た。こうして得たポリハロゲン化合物分散物に含まれる有機ポリハロゲン化合物粒子はメジアン径０．３６μｍ、最大粒子径１．５μｍ以下であった。得られた有機ポリハロゲン化合物分散物は孔径３．０μｍのポリプロピレン製フィルターにてろ過を行い、ゴミ等の異物を除去して収納した。
【０２４５】
６）フタラジン化合物−１溶液の調製
８ｋｇの変性ポリビニルアルコールＭＰ２０３を水１７４．５７ｋｇに溶解し、次いでトリイソプロピルナフタレンスルホン酸ナトリウムの２０質量％水溶液３．１５ｋｇとフタラジン化合物−１（６−イソプロピルフタラジン）の７０質量％水溶液１４．２８ｋｇを添加し、フタラジン化合物−１の５質量％溶液を調製した。
【０２４６】
７）メルカプト化合物−１水溶液の調製
７ｇのメルカプト化合物−１を水９９３ｇに溶解し、０．７質量％の水溶液とした。
【０２４７】
８）顔料−１分散物の調製
Ｃ．Ｉ．Ｐｉｇｍｅｎｔ　Ｂｌｕｅ　６０を６４ｇと花王（株）製デモールＮを６．４ｇに水２５０ｇを添加しよく混合してスラリーとした。平均直径０．５ｍｍのジルコニアビーズ８００ｇを用意してスラリーと一緒にベッセルに入れ、分散機（１／４Ｇサンドグラインダーミル：アイメックス（株）製）にて２５時間分散した後、ベッセルより取出し、水で希釈して顔料濃度５質量％の顔料−１分散物を得た。こうして得た顔料分散物に含まれる顔料粒子は平均粒径０．２１μｍであった。
【０２４８】
９）ＳＢＲラテックス液の調製
Ｔｇ＝２３℃のＳＢＲラテックスは以下により調整した。
重合開始剤として過硫酸アンモニウム、乳化剤としてアニオン界面活性剤を使用し、スチレン７０．５質量部、ブタジエン２６．５質量部およびアクリル酸３質量部を乳化重合させた後、８０℃で８時間エージングを行った。その後４０℃まで冷却し、アンモニア水によりｐＨ７．０とし、さらに三洋化成（株）製サンデットＢＬを０．２２％になるように添加した。次に５％水酸化ナトリウム水溶液を添加しｐＨ８．３とし、さらにアンモニア水によりｐＨ８．４になるように調整した。このとき使用したＮａ^＋イオンとＮＨ_４ ^＋イオンのモル比は１：２．３であった。さらに、この液１ｋｇ対してベンゾイソチアゾリンノンナトリウム塩７％水溶液を０．１５ｍｌ添加しＳＢＲラテックス液を調製した。
【０２４９】
（ＳＢＲラテックス：−Ｓｔ（７０．５）−Ｂｕ（２６．５）−ＡＡ（３）−のラテックス）
Ｔｇ＝２３℃平均粒径０．１μｍ、濃度４３質量％、２５℃６０％ＲＨにおける平衡含水率０．６質量％、イオン伝導度４．２ｍＳ／ｃｍ（イオン伝導度の測定は東亜電波工業（株）製伝導度計ＣＭ−３０Ｓ使用し、ラテックス原液（４３質量％）を２５℃にて測定）、ｐＨ８．４。
Ｔｇの異なるＳＢＲラテックスはスチレン、ブタジエンの比率を適宜変更し、同様の方法により調整した。
【０２５０】
３−２．塗布液の調製
１）画像形成層の塗布液の調製
上記で得た脂肪酸銀分散物１０００ｇ、水１０４ｍｌ、顔料−１分散物３０ｇ、有機ポリハロゲン化合分散物（ａ）６．３ｇ、有機ポリハロゲン化合物分散物（ｂ）２０．７ｇ、フタラジン化合物−１溶液１７３ｇ、ＳＢＲラテックス（Ｔｇ：２３℃）液１０８２ｇ、還元剤分散物（ａ）２５８ｇ、メルカプト化合物−１溶液９ｇを順次添加し、塗布直前に各塗布液添加用乳剤１ａ〜１ｃ、１〜７を有機酸銀に対する量が銀のモル比で６．６％になるように添加し、よく混合した画像形成層塗布液１ａ〜１ｃ、１〜７を調製し、そのままコーティングダイへ送液し、塗布した。
【０２５１】
２）中間層塗布液の調製
ポリビニルアルコールＰＶＡ−２０５（クラレ（株）製）の１０質量％水溶液７７２ｇ、顔料−１分散物５．３ｇ、メチルメタクリレート／スチレン／ブチルアクリレート／ヒドロキシエチルメタクリレート／アクリル酸共重合体（共重合質量比６４／９／２０／５／２）ラテックス２７．５質量％液２２６ｇにエアロゾールＯＴの５質量％水溶液を２ｍｌ、フタル酸二アンモニウム塩の２０質量％水溶液を１０．５ｍｌ、総量８８０ｇになるように水を加え、ｐＨが７．５になるようにＮａＯＨで調整して中間層塗布液とし、１０ｍｌ／ｍ^２になるようにコーティングダイへ送液した。
塗布液の粘度はＢ型粘度計４０℃（Ｎｏ．１ローター、６０ｒｐｍ）で６５［ｍＰａ・ｓ］であった。
【０２５２】
３）表面保護層第１層塗布液の調製
イナートゼラチン６４ｇを水に溶解し、メチルメタクリレート／スチレン／ブチルアクリレート／ヒドロキシエチルメタクリレート／アクリル酸共重合体（共重合質量比６４／９／２０／５／２）ラテックス２７．５質量％液８０ｇ、フタル酸の１０質量％メタノール溶液を２３ｍｌ、４−メチルフタル酸の１０質量％水溶液２３ｍｌ、０．５ｍｏｌ／Ｌ濃度の硫酸を２８ｍｌ、エアロゾールＯＴの５質量％水溶液を５ｍｌ、フェノキシエタノール０．５ｇ、ベンゾイソチアゾリノン０．１ｇを加え、総量７５０ｇになるように水を加えて塗布液とし、４質量％のクロムみょうばん２６ｍｌを塗布直前にスタチックミキサーで混合したものを１８．６ｍｌ／ｍ^２になるようにコーティングダイへ送液した。
塗布液の粘度はＢ型粘度計４０℃（Ｎｏ．１ローター、６０ｒｐｍ）で２０［ｍＰａ・ｓ］であった。
【０２５３】
４）表面保護層第２層塗布液の調製
イナートゼラチン８０ｇを水に溶解し、メチルメタクリレート／スチレン／ブチルアクリレート／ヒドロキシエチルメタクリレート／アクリル酸共重合体（共重合質量比６４／９／２０／５／２）ラテックス２７．５質量％液１０２ｇ、フッ素系界面活性剤（Ｆ−１）の５質量％溶液を３．２ｍｌ、フッ素系界面活性剤（Ｆ−２）の２質量％水溶液を３２ｍｌ、エアロゾールＯＴの５質量％溶液を２３ｍｌ、ポリメチルメタクリレート微粒子（平均粒径０．７μｍ）４ｇ、ポリメチルメタクリレート微粒子（平均粒径４．５μｍ）２１ｇ、４−メチルフタル酸１．６ｇ、フタル酸４．８ｇ、０．５ｍｏｌ／Ｌ濃度の硫酸４４ｍｌ、ベンゾイソチアゾリノン１０ｍｇに総量６５０ｇとなるよう水を添加して、４質量％のクロムみょうばんと０．６７質量％のフタル酸を含有する水溶液４４５ｍｌを塗布直前にスタチックミキサーで混合したものを表面保護層第２層塗布液とし、８．３ｍｌ／ｍ^２になるようにコーティングダイへ送液した。
塗布液の粘度はＢ型粘度計４０℃（Ｎｏ．１ローター，６０ｒｐｍ）で１９［ｍＰａ・ｓ］であった。
【０２５４】
３−３．熱現像感光材料１ａ〜１ｃ、１〜７の作成
【０２５５】
バック面と反対の面に、順に、画像形成層、中間層、表面保護層第１層、表面保護層第２層の順番でスライドビード塗布方式にて同時重層塗布し、熱現像感光材料の試料を作成した。このとき、画像形成層と中間層の塗布液は３５℃に、表面保護層第１層は３６℃に、表面保護層第２層は３７℃に温度調整した。
画像形成層の各化合物の塗布量（ｇ／ｍ^２）は以下の通りである。
【０２５６】
ベヘン酸銀　　　　　　　　　　　　　　　　　　　６．１９
顔料（Ｃ．Ｉ．Ｐｉｇｍｅｎｔ　Ｂｌｕｅ　６０）　　　　　　　　　　　　　０．０３６
ポリハロゲン化合物−１　　　　　　　　　　　　　０．０４
ポリハロゲン化合物−２　　　　　　　　　　　　　０．１２
フタラジン化合物−１　　　　　　　　　　　　　　０．２１
ＳＢＲラテックス　　　　　　　　　　　　　　　　　１１．１
還元剤錯体−１　　　　　　　　　　　　　　　　　１．５４
メルカプト化合物−１　　　　　　　　　　　　　　０．００２
ハロゲン化銀（Ａｇとして）　　　　　　　　　　　０．１０
タイプ１〜４の化合物（表１に示す）
ハロゲン化銀１モル当たり１×１０^−３モル
【０２５７】
塗布乾燥条件は以下のとおりである。
塗布はスピード１６０ｍ／ｍｉｎで行い、コーティングダイ先端と支持体との間隙を０．１０〜０．３０ｍｍとし、減圧室の圧力を大気圧に対して１９６〜８８２Ｐａ低く設定した。支持体は塗布前にイオン風にて除電した。
引き続くチリングゾーンにて、乾球温度１０〜２０℃の風にて塗布液を冷却した後、無接触型搬送して、つるまき式無接触型乾燥装置にて、乾球温度２３〜４５℃、湿球温度１５〜２１℃の乾燥風で乾燥させた。このようにして塗布試料２１から２７を得た。
乾燥後、２５℃で湿度４０〜６０％ＲＨで調湿した後、膜面を７０〜９０℃になるように加熱した。加熱後、膜面を２５℃まで冷却した。
【０２５８】
作製された熱現像感光材料のマット度はベック平滑度で画像形成層面側が５５０秒、バック面が１３０秒であった。また、画像形成層面側の膜面のｐＨを測定したところ６．０であった。
【０２５９】
以下に本発明の実施例で用いた化合物の化学構造を示す。
【０２６０】
【化１１】

【０２６１】
【化１２】

【０２６２】
【化１３】

【０２６３】
【化１４】

【０２６４】
【化１５】

【０２６５】
４．写真性能の評価
（準備）
得られた試料は半切サイズに切断し、２５℃５０％の環境下で以下の包装材料に包装し、２週間常温下で保管した。
（包装材料）
ＰＥＴ１０μｍ／ＰＥ１２μｍ／アルミ箔９μｍ／Ｎｙ１５μｍ／カーボン３％を含むポリエチレン５０μｍ、酸素透過率：０．０２ｍｌ／ａｔｍ・ｍ^２・２５℃・ｄａｙ、水分透過率：０．１０ｇ／ａｔｍ・ｍ^２・２５℃・ｄａｙ。
【０２６６】
上記の熱現像感光材料を以下のように評価を行った。
（感光材料の露光）
感光材料は以下の様にして露光処理を行った。
富士メディカルドライレーザーイメージャーＦＭ−ＤＰＬを改造して露光・現像処理を行った。露光はＦＭ−ＤＰＬ搭載の最大６０ｍＷ（ＩＩＩＢ）出力の６６０ｎｍ半導体レーザーを１００μｍ×１００μｍに絞って感材を照射した。レーザーの露光量を段階的に変化させて露光を行った。現像は、ＦＭ−ＤＰＬの熱現像部を用いて、１１２℃−１１９℃−１２１℃−１２１℃に設定した４枚のパネルヒーターで、合計２４秒であった。
【０２６７】
（試料の評価）　得られた画像をＭａｃｂｅｔｈ濃度計で濃度測定し露光量の対数に対する濃度の特性曲線を作成した。
感度：カブリ＋１．０の黒化濃度を与える露光量の逆数で感度を表し、試料Ｎｏ．１の感度を１００としてそれに対する相対値で示した。値が大きいほど感度が高いことを示す。
Ｄｍｉｎ：非画像部の濃度をマクベス濃度計により測定した。
画像保存性：熱現像した試料を半切サイズに切断し、３０℃７０％ＲＨの環境下で、照度１０００Ｌｕｘの蛍光灯下で２４時間保存した後、Ｄｍｉｎ部のかぶり濃度の増加を評価した。
【０２６８】
得られた結果は表１に示す。この結果が示すように、本発明の熱現像感光材料は、２種以上の金属ドープによって、高い感度が得られ、かつ、Ｄｍｉｎは低いレベルを維持し、熱現像後のプリントアウト性能もヨウ化銀乳剤を用いた特徴である良好なレベルを維持していた。
【０２６９】
【表１】

【０２７０】
実施例２
実施例１のハロゲン化銀乳剤と同様にして、但し増感色素ＡとＢを添加しないでヨウ化銀乳剤を調製し、その他は実施例１と同様にして塗布試料２ａ，２ｂ，２１から２７を得た。そのあと４０５ｎｍの青色レーザー光を用いる以外は実施例１と同様に処理を行い、表２の結果を得た。なお、相対感度は試料２１を１００として相対比で示した。
【０２７１】
【表２】

【０２７２】
表２から明らかなように、本発明の熱現像感光材料は、２種以上の金属ドープによって、高い感度が得られ、かつ、Ｄｍｉｎは低いレベルを維持し、熱現像後のプリントアウト性能もヨウ化銀乳剤を用いた特徴である良好なレベルを維持していた。
【０２７３】
実施例３
実施例１において、感光性ハロゲン化銀乳剤のドープ金属の種類を表３に示すように変更して、乳剤を調製した。第一の金属は、銀１モル当たり５×１０^−４モル添加し、第二の金属は、銀１モル当たり３×１０^−３モル添加した。
【０２７４】
実施例１と同様に評価した結果を表３に示した。感度は、それぞれ第一の金属を単独使用した場合を１００として相対感度で表し、２つの金属ドープの併用効果が明確にわかるように示した。実施例１と同様に、本発明の熱現像感光材料は、２種の金属ドープによって、高い感度が得られ、かつ、Ｄｍｉｎは低いレベルを維持し、熱現像後のプリントアウト性能もヨウ化銀乳剤を用いた特徴である良好なレベルを維持していた。
【０２７５】
【表３】

【０２７６】
【発明の効果】
本発明により、熱現像処理後の画像のプリントアウト性能に優れ、かつ高感度で低いＤｍｉｎの熱現像感光材料が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photothermographic material, and more particularly to a photothermographic material using a silver halide emulsion having a high silver iodide content, and has high sensitivity and low fog and excellent image storability after development processing. The present invention relates to a photothermographic material.
[0002]
[Prior art]
In recent years, in the medical field and the printing plate making field, dry development of photographic development processing is strongly desired from the viewpoint of environmental protection and space saving. In these areas, digitization has progressed, and image information is captured and stored on a computer, stored, and processed if necessary, and output to photosensitive materials by laser image setter or laser imager where necessary by communication. However, systems for developing and creating images on the spot are rapidly spreading. As a photosensitive material, it is necessary to form a clear black image that can be recorded by laser exposure with high illuminance and has high resolution and sharpness. As such digital imaging recording materials, various hard copy systems using pigments and dyes such as inkjet printers and electrophotography are distributed as general image forming systems, but the diagnostic ability is determined like medical images. It is unsatisfactory in terms of image quality (sharpness, graininess, gradation, color tone) and recording speed (sensitivity), and has not yet reached a level that can replace the conventional silver salt film for wet development.
[0003]
On the other hand, thermal imaging systems using organic silver salts are disclosed in, for example, the specifications of U.S. Pat. “Thermally Processed Silver Systems” (Imaging Processes and Materials) Nebelte 8th Edition, Sturge. (Walworth), A. Shepp (2nd page, 1996). In particular, a photothermographic material generally contains a photosensitive silver halide, a reducing agent, a reducible silver salt (eg, an organic silver salt), and, if necessary, a toning agent for controlling the color tone of silver dispersed in a binder matrix. A photosensitive layer.
[0004]
The photothermographic material is heated to a high temperature (for example, 80 ° C. or higher) after image exposure, and is blackened by an oxidation-reduction reaction between silver halide or a reducible silver salt (functioning as an oxidizing agent) and a reducing agent. Form a silver image. The oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide generated by exposure. As a result, a black silver image is formed in the exposed area. The photothermographic material is disclosed in many documents including US Pat. No. 2,910,377 and Japanese Patent Publication No. 43-4924. In addition, Fuji Medical Dry Imager FM-DP L is practically used as a medical image forming system. Released.
[0005]
In such an image forming system using an organic silver salt, since there is no fixing step, image storage stability after development processing, in particular, deterioration of printout when exposed to light has been a serious problem. Methods for utilizing silver iodide formed by converting an organic silver salt as means for improving this printout are disclosed in US Pat. No. 6,143,488 and EP0922995. However, the method of converting an organic silver salt as disclosed herein with iodine cannot obtain sufficient sensitivity, and it is difficult to construct an actual system. Other photosensitive materials using silver iodide are described in WO97-48014, WO48015, US-6165705, JP-A-8-297345, Japanese Patent No. 2785129, etc., all of which have sufficient sensitivity and fogging level. Was not able to be achieved, and could not withstand practical use as a laser exposure sensitive material.
[0006]
As means for increasing the sensitivity of silver iodide photographic emulsions, Journal of Photographic Science, Vol. 8, 119, 1960, Yaku, 28, 163, 1980, Photographic Science and Engineering, 5, 216 In 1961, etc., it has been known that sensitization is performed by immersion in a halogen acceptor such as sodium nitrite, pyrogallol, hydroquinone, or a silver nitrate aqueous solution, or by sulfur sensitization with pAg7.5. However, as shown in the Examples, the sensitizing effect of these halogen acceptors was very small and extremely insufficient in the photothermographic material targeted by the present invention.
[0007]
Doping light-sensitive silver halides with heavy metal ions has been conventionally performed with various silver halides. For example, Japanese Patent Application Laid-Open No. 2001-42471 describes that a silver halide grain is doped with a transition metal from Group 6 to Group 10 in the periodic table. It is described that the distribution of these doped metals in the particles is preferably distributed more on the surface or in the vicinity of the surface than the inside, or evenly distributed in the particles, which contributes to high sensitivity. As silver halide, silver bromide, silver iodobromide, silver chloroiodobromide are described, and the content of silver iodide is 0.01 mol% to 10 mol%, and 0.0.1 mol%. -5 mol% is a preferable range.
[0008]
On the other hand, Japanese Patent Application Laid-Open No. 2000-66325 discloses a method of doping an iridium-based dopant and a transition metal dopant other than iridium into different regions of silver halide grains, whereby high sensitivity, particularly sensitivity at high illumination exposure. The effect of increasing the amount is explained. As the silver halide, silver bromide, silver iodobromide, and silver chloroiodobromide are described as described above, and the silver iodide content is 0.01 mol% to 10 mol%. 0.1 mol% to 5 mol% is a preferred range. Also, it is described that a multicolor color light-sensitive material having two or more silver halide emulsion layers is suitable for use, and the photothermographic material is not mentioned at all.
[0009]
As described above, for silver halide emulsions having a silver iodide content of 10 mol% or less, preferred heavy metal types and addition methods thereof are known, but a high silver iodide content of 40 mol% or more is known. There has been no knowledge of silver halide in the past. The silver halide having a high silver iodide content in this region is completely different in properties from a silver halide emulsion having a silver iodide content of 10 mol% or less. Regarding the doping of heavy metal ions, the knowledge of silver halide emulsions having a silver iodide content of 10 mol% or less could not be applied, and new technical development was required.
As described above, silver halide itself having such a high silver iodide content has not been practically used in the past, so there was no interest in its heavy metal doping. Furthermore, no attempt was made to apply it to a photothermographic material.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to provide a photothermographic material having high sensitivity and low fog and excellent in image storability in a photothermographic material using high silver iodide.
[0011]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following means.
1) In a photothermographic material containing at least photosensitive silver halide, non-photosensitive organic silver salt, a reducing agent for silver ions, and a binder on one side of the support, the photosensitive silver halide 1) The silver iodide content is 40 mol% or more and 100 mol% or less, and 2) at least one metal selected from the following first metal group and at least one selected from the following second metal group A photothermographic material comprising a seed metal.
(First metal group)
Iridium, ruthenium, iron, osmium
(Second metal group)
Ruthenium, iron, osmium, rhenium, gold, platinum, copper, indium, gallium, lead, thallium, chromium, palladium, nickel, zinc
However, the metal selected from the first metal group and the metal selected from the second metal group are not the same.
2) The photothermographic material according to 1), wherein the first metal and the second metal are selected from the following combinations.
(Ir-Fe), (Ir-Cu), (Ru-Cu), (Ru-Fe), (Fe-Os), (Fe-Ru), (Fe-Cu), (Fe-Pt), (Os -Cu), (Os-Fe), (Cu-Fe), (Cu-Ru)
3) The first metal and the second metal are (Ir-Fe), (Ru-Fe), (Fe-Cu), (Fe-Pt), (Ru-Cu), (Os-Fe), (Cu The photothermographic material according to 1) or 2), which is selected from a combination of -Fe) and (Cu-Ru).
4) The photothermographic material according to claim 1, wherein the first metal is distributed in the core and the second metal is distributed in the shell.
5) The photothermographic material according to 1) to 4), wherein the silver halide emulsion is chemically sensitized with at least one of chalcogen sensitization, gold sensitization, and reduction sensitization.
6) The photothermographic material according to 5), wherein the chalcogen sensitization is tellurium sensitization, selenium sensitization, or sulfur sensitization.
7) The photothermographic material according to 5) or 6), wherein the chalcogen sensitization is tellurium sensitization and selenium sensitization.
8) The photothermographic material according to 5) to 7), wherein the chalcogen sensitization is tellurium sensitization. 9) The photothermographic material according to any one of 1) to 8), wherein the silver halide content of the silver halide photographic emulsion is from 80 mol% to 100 mol%.
10) The photothermographic material according to 9), wherein the silver halide content of the silver halide photographic emulsion is 90 mol% or more and 100 mol% or less.
11) The photothermographic material according to 1) to 10), wherein the silver halide grain size is 50 nm or less and 5 nm or more.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
1. Photothermographic material
The photothermographic material of the present invention has an image forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent, and a binder on at least one surface of a support. Moreover, it is preferable to have a surface protective layer on the image forming layer, or a back layer or a back protective layer on the opposite side.
The configuration of each layer and preferred components thereof will be described in detail.
[0013]
1-1. Image forming layer
1-1-1. Photosensitive silver halide
1) Halogen composition
It is important that the photosensitive silver halide used in the present invention has a high silver iodide content of 40 mol% or more and 100 mol% or less. The rest is not particularly limited and can be selected from silver chloride, silver bromide, or organic silver salts such as silver thiocyanate and silver phosphate. Silver bromide and silver chloride are particularly preferred. By using such a silver halide having a high silver iodide content, it is possible to design a preferable photothermographic material in which image storage stability after development processing, in particular, an increase in fog due to light irradiation is remarkably small.
[0014]
Further, the silver iodide content is preferably 80 mol% or more and 100 mol% or less, and particularly 85 mol% or more and 100 mol% or less, or 90 mol% or more and 100 mol% or less with respect to light irradiation after the treatment. This is extremely preferable from the viewpoint of image storage stability.
[0015]
The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be continuously changed. Further, silver halide grains having a core / shell structure can also be preferably used. A preferable structure is a 2- to 5-fold structure, more preferably 2- to 4-fold core / shell particles. A core high silver iodide structure having a high silver iodide content in the core part or a shell high silver iodide structure having a high silver iodide content in the shell part can also be preferably used. Further, a technique of localizing silver chloride or silver bromide as an epitaxial portion on the surface of the grain can be preferably used.
[0016]
2) Particle size
The grain size is particularly important for high silver iodide silver halides used in the present invention. Larger silver halide sizes increase the amount of silver halide coating required to achieve the required maximum density. The present inventor found that the silver halide composition having a high silver iodide content preferably used in the present invention, when the coating amount is large, the development is remarkably suppressed and the sensitivity is lowered, and the density stability with respect to the development time deteriorates. It has been found that the maximum density cannot be obtained in a predetermined development time when the particle size is not less than a certain value. On the other hand, it has been found that if the amount added is limited, the silver iodide has sufficient developability.
[0017]
In this way, when using high silver iodide, the size of the silver halide grains is sufficiently larger than that of conventional silver bromide and silver iodide containing low iodine to achieve a sufficient maximum optical density. It needs to be small. The preferred silver halide grain size is 5 nm or more and 70 nm or less, and more preferably 5 nm or more and 55 nm or less.
Especially preferably, it is 10 nm or more and 45 nm or less. The term “particle size” as used herein means an average diameter when converted into a circular image having the same area as the projected area observed with an electron microscope.
[0018]
3) Application amount
The coating amount of such silver halide grains is 0.5 mol% or more and 15 mol% or less, preferably 0.5 mol% or more and 12 mol% or less with respect to 1 mol of silver of the non-photosensitive organic silver salt described later. More preferably, it is 10 mol% or less. It is more preferably 1 mol% or more and 9 mol% or less, and particularly preferably 1 mol% or more and 7 mol% or less. In order to suppress remarkable development suppression by the silver halide having a high silver iodide content found by the present inventor, the selection of the addition amount is extremely important.
[0019]
4) Particle formation method
Methods for forming photosensitive silver halide are well known in the art, for example using the methods described in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. Specifically, there is used a method in which a photosensitive silver halide is prepared by adding a silver supply compound and a halogen supply compound to gelatin or another polymer solution, and then mixed with an organic silver salt. Further, the method described in paragraph Nos. 0217 to 0224 of JP-A No. 11-119374, and the method described in JP-A No. 11-352627 and Japanese Patent Application No. 2000-42336 are also preferable.
[0020]
5) Particle shape
Examples of the shape of the silver halide grains include cubic grains, octahedral grains, tetrahedral grains, dodecahedron grains, tabular grains, spherical grains, rod-shaped grains, and potato-like grains. In particular, dodecahedral grains, tetrahedral grains, and tabular grains are preferable.
The silver halide having a high silver iodide content composition of the present invention can take a complicated form. L. JENKINS et al. J of Photo. Sci. Vol. 28 (1980), p164-FIG1. FIG. Tabular grains as shown in Fig. 1 are also preferably used. Grains with rounded corners of silver halide grains can also be preferably used. The surface index (Miller index) of the outer surface of the photosensitive silver halide grain is not particularly limited, but the ratio of the [100] plane having high spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of the Miller index [100] plane is determined by T.T. Tani; Imaging Sci. 29, 165 (1985).
[0021]
6) Heavy metal
The photosensitive silver halide of the present invention is characterized by containing at least a first doping metal and a second doping metal.
[0022]
In the present invention, the combined use of the first doping metal and the second doping metal results in higher sensitivity than the single use due to the synergistic effect. These metals are preferably localized in different regions inside the silver halide grains. For example, it is preferable that a large amount of the first metal is present in the core portion of the particle and a large amount of the second metal is present in the shell portion of the particle. Or conversely, it is also preferable to localize the first metal in the shell and the second metal in the core. Alternatively, the first metal can be localized in the shell and the second metal can be evenly distributed throughout the particles. Each sensitizing effect can be expressed synergistically by being localized in different regions in the particle.
[0023]
In order to dope silver halide grains with these metals, a water-soluble halogen ion solution or a silver nitrate aqueous solution is mixed with a complex salt of these heavy metals at the time of silver halide grain formation. Usually, the method of incorporating into is performed. The method of localizing inside the crystal is controlled by the timing of mixing these metals in the crystal growth stage of silver halide grains. For example, when more localized in the core, a doped metal is added in the initial stage of grain formation. In order to localize more in the shell part, it is mixed later, or after the formation of particles, these doped metals are doped into other fine particles, and these fine particles are mixed to transfer metal ions between the particles. Methods can also be used.
[0024]
6-1) First metal group
The first metal is selected from the group consisting of iridium, ruthenium, iron, osmium, and copper. Among these, iridium and iron are more preferable, and iridium and copper are particularly preferable.
It is preferable to use a metal complex having these metals as a central metal.
[0025]
For example, the metal complex having iridium as the central metal is a trivalent or tetravalent iridium complex. For example, hexachloroiridium (III) complex salt, hexachloroiridium (IV) complex salt, hexabromoiridium (III) complex salt, hexabromo Iridium (IV) complex salt, hexaiodoiridium (III) complex salt, hexaiodoiridium (IV) complex salt, aquapentachloroiridium (III) complex salt, aquapentachloroiridium (IV) complex salt, aquapentabromoiridium (III) complex salt, aqua Pentabromoiridium (IV) complex salt, aqua pentaiodoiridium (III) complex salt, aqua pentaiodoiridium (IV) complex salt, diaquatetrachloroiridium (III) complex salt, diaquatetrachloroiridium (IV) complex salt Diaquatetrabromoiridium (III) complex salt, diaquatetrabromoiridium (IV) complex salt, diaquatetraiodoiridium (III) complex salt, diaquatetraiodoiridium (IV) complex salt, triaquatrichloroiridium (III) complex salt, triaqua Aquatrichloroiridium (IV) complex salt, triaquatribromoiridium (III) complex salt, triaquatribromoiridium (IV) complex salt, triaquatriiodoiridium (III) complex salt, triaquatriiodoiridium (IV) complex salt, hexaammine Iridium (III) complex salt, hexaammineiridium (IV) complex salt, hexachlororuthenium (II) complex salt, hexabromoruthenium (II) complex salt, hexaiodolthenium (II) complex salt, aquapentachlororuthenium II) Complex salt, Nitrosylpentachlororuthenium (II) complex salt, Aquapentabromoruthenium (II) complex salt, Nitrosylpentabromoruthenium (II) complex salt, Aquapentaiodolthenium (II) complex salt, Nitrosylpentaiodolthenium (II) complex salt, Di Aquatetrachlororuthenium (II) complex salt, diaquatetrabromoruthenium (II) complex salt, diaquatetraioruthenium (II) complex salt, triaquatribromoruthenium (II) complex salt, triaquatrichlororuthenium (II) complex salt, hexaammine Ruthenium (II) complex salt, hexacyanoruthenium (II) complex salt, hexachloroiron (II) complex salt, hexabromoiron (II) complex salt, hexaiodoiron (II) complex salt, aquapentachloroiron (II) complex salt, aquapentabromoiron (II) complex salt, aqua pentaiodo iron (II) complex salt, diaqua tetrachloro iron (II) complex salt, diaqua tetrabromo iron (II) complex salt, diaqua tetraioto iron (II) complex salt, triaqua tribromo iron ( II) Complex salt, triaquatrichloroiron (II) complex salt, hexaammine iron (II) complex salt, hexacyanoiron (II) complex salt, hexachloroosmium (II) complex salt, hexabromoosmium (II) complex salt, hexaiodoosmium (II) complex salt , Aquapentachloroosmium (II) complex salt, aquapentabromoosmium (II) complex salt, aquapentaiodoosmium (II) complex salt, diaquatetrachloroosmium (II) complex salt, diaquatetrabromoosmium (II) complex salt, diaqua Tetraiotoosmium (II) complex salt, triaquatri Lomoosmium (II) complex salt, triaquatrichloroosmium (II) complex salt, hexaammineosmium (II) complex salt, hexacyanoosmium (II) complex salt, copper acetate (I), copper acetate (II), copper nitrate (I), nitric acid Copper (II), tetrachloro copper (I) complex salt, tetrachloro copper (II) complex salt, tetrabromo copper (I) complex salt, tetrabromo copper (II) complex salt, tetraiodo copper (I) complex salt, tetraiodo copper (II) complex salt, tetraammine Copper (I) complex salt, tetraammine copper (II) complex salt, tetracyano copper (I) complex salt, tetracyano copper (II) complex salt can be mentioned.
[0026]
In the present invention, the amount of the first metal added is 1 × 10 5 per mole of silver halide.^-8Mol ~ 1 × 10^-1Mole, more preferably 1 × 10^-6Mol ~ 1 × 10^-2The range of moles.
[0027]
In the present invention, the first metal may be distributed in any part of the silver halide grains. The particles may be distributed uniformly in the particle, or may be localized in the core part, the middle shell part, the surface or the vicinity of the surface (shell) of the particle.
When making it local, a core part is preferable.
[0028]
6-2) Second metal group
The second metal is selected from the metal group of ruthenium, iron, rhenium, gold, platinum, copper, indium, gallium, lead, thallium, chromium, palladium, nickel, and zinc.
Of these, ruthenium, iron, rhenium, gold, platinum, and copper are more preferable, and ruthenium and iron are particularly preferable.
These metals are preferably added as metal complex salts in the same manner as the first metal.
[0029]
These metals may be distributed uniformly throughout the silver halide grains, or may be localized in the core portion, the middle shell portion, the surface, or the vicinity of the surface (shell) of the grains.
In the case of localizing, the surface or the vicinity of the surface (shell) is preferable.
[0030]
The doping amount of the second metal is 1 × 10 6 per mole of silver halide.^-8Mol ~ 1 × 10^-1Moles are preferred, more preferably 1 × 10^-6Mol ~ 1 × 10^-2Mole, more preferably 1 × 10^-5Mol ~ 5 × 10^-3Is a mole.
[0031]
Specific examples of the metal complex used in the present invention are shown below, but the present invention is not limited thereto.
[0032]
K₄[Fe (CN)₆]
K₃[Fe (CN)₆]
K₄[Ru (CN)₆]
K₄[Os (CN)₆]
K₃[Co (CN)₆]
K₃[Rh (CN)₆]
K₃[Cr (CN)₆]
K₃[Re (CN)₆]
K₂[Rh (H₂O) Cl₅]
K₃[RhCl₆]
K₃[RuCl₆]
K₃[ReCl₆]
K₃[RuBr₆]
K₃[OsCl₆]
K₃[CrCl₆]
K₃[RhBr₆]
CuCl
CuCl₂
CuBr
CuBr₂
CuI
CH₃CO₂Cu
(CH₃CO₂)₂Cu
(CH₃CO₂)₂Co
(CH₃CO₂)₂Fe
(CH₃CO₂)₂Rh
CoI₂
Co (OH)₂
K₂[Ru (H₂O) Cl₅]
K₂[Ru (NO) Cl₅]
K₂[Pd (CN)₄]
K₂[PdCl₄]
K₂[PdBr₄]
K₂[Pd (NO₂)₄]
K₂[Pd (SCN)₄]
K₂[Pt (CN)₄]
K₂[PtCl₄]
K₂[PtBr₄]
K₂[PtI₄]
K₂[Pt (NO₂)₄]
K₂[Pt (SCN)₄]
K₂[Pt (NO₂)₂(NH₃)₂]
trans- [PtCl₂(NH₃)₂]
cis- [PtCl₂(NH₃)₂]
K₂[Co (NCO)₄]
K₂[CoCl₄]
K₂[CoBr₄]
[CoCl₂(H₂O)₂]
K₂[Ni (CN)₄]
K₂[NiCl₄]
K₂[Ni (SCN)₄]
K [Au (CN)₄]
K [AuCl₄]
K [AuI₄]
K [Pt (CN)₃(Py)] py is pyridine.
K [Pd (CN)₃(Py)]
K [Pt (CN)₂(Bpy)] bpy is 2,2'-bipyridine.
K [Pd (CN)₂(Bpy)]
K [Pt (CN)₃(Pyz)] pyz is pyrazine.
K [Pd (CN)₃(Pyz)]
[Pt (CN) (py)₃] Cl
[Pt (CN) (pyz)₃] Cl
[Pt (pyz)₂Cl₂]
[Fe (py)₄Cl₂]
K₄[Pd (py)₂Cl₂]
[Co (py)₂Cl₂]
[Ag (py)₄Cl₂]
K [Pt (CN)₃(Py)]
K [Zn (CN)₃(Py)]
[Zn (CN)₂(Bpy)]
[Zn (CN)₂Cl₂]
K [Zn (CN)₃(Pyz)]
K₂[Zn (CN)₄]
K₂[ZnCl₄]
K₂[ZnI₄]
K₂[Cu (CN)₃(Py)]
K [Cu (CN)₂(Bpy)]
K₃[Cu (CN)₂Cl₂]
K₂[Cu (CN)₃(Pyz)]
K₃[Cu (CN)₄]
K₃[CuCl₄]
K₃[CuI₄]
K [Au (CN)₂(Bpy)]
K₃[Au (CN)₂Cl₂]
K₂[Au (CN)₃(Pyz)]
K [PtCl₂(Im)₂] Im is imidazole.
[ZnCl₂(Im)₂]
K [PdCl (Im)₃]
K [PdCl₂(Im)₂]
K [CuCl₂(Im)₂]
K [AuCl₂(Im)₂]
K [CoCl₃(Im)]
[CoCl₂(Im)₂]
[CoCl (Im)₃] Cl
[Co (Im)₄] Cl₂
K [Co (CN)₃(Im)]
[Co (CN)₂(Im)₂]
[Co (CN) (Im)₃] Cl
[CoCl₂(Bim)₂] Bim is benzimidazole.
[CoCl (bim)₃] Cl
[Co (bim)₄] Cl₂
K [Pt (CN)₂(Phen)] Phen is 1,10-phenanthroline.
[Zn (CN)₂(Phen)]
K [Cu (CN)₂(Phen)]
K [Au (CN)₂(Phen)]
K [Co (CN)₂(Phen)]
[0033]
6-3) Others
In addition to the above metals, the photosensitive silver halide grains of the present invention include, as third metals, JP-A-7-225449, JP-A-11-65021, paragraph numbers 0018 to 0024, and JP-A-11-119374, paragraph numbers. You may contain the metal salt described in 0227-0240, or a metal complex.
[0034]
6-4) Quantification of doped metal and measurement of its intraparticle distribution
The quantification and distribution of these doped metals in the photosensitive silver halide grains prepared by the grain forming method according to the present invention can be confirmed by the method described in JP-A No. 2001-42471. it can. First, gelatin is separated by adding an aqueous actinase solution and centrifuging. Then, the silver halide grains are gradually dissolved from the surface with a silver halide solvent such as an aqueous ammonia solution or an aqueous potassium cyanide solution, and the concentration of metal ions present in the supernatant is determined using a high frequency induction plasma emission analyzer (ICP-MS), high frequency induction. It can be quantified by plasma emission analyzer (ICP-AFS) or atomic absorption.
[0035]
7) Gelatin
Various gelatins can be used as the gelatin contained in the photosensitive silver halide emulsion used in the present invention. In order to satisfactorily maintain the dispersion state of the photosensitive silver halide emulsion in the organic silver salt-containing coating solution, it is preferable to use low molecular weight gelatin having a molecular weight of 500 to 60,000. These low molecular weight gelatins may be used at the time of particle formation or dispersion after desalting, but are preferably used at the time of dispersion after desalting.
[0036]
8) Chemical sensitization
The photosensitive silver halide used in the present invention may be non-chemically sensitized, but is preferably chemically sensitized by at least one of a chalcogen sensitizing method, a gold sensitizing method, and a reduction sensitizing method. Examples of the chalcogen sensitizing method include a sulfur sensitizing method, a selenium sensitizing method, and a tellurium sensitizing method.
[0037]
In sulfur sensitization, unstable sulfur compounds are used. The unstable sulfur compounds described in Grafkides, Chimie et Physique Photographic (published by Paul Momtel, 1987, 5th edition), Research Disclosure 307, 307105, and the like can be used.
Specifically, thiosulfate (for example, hypo), thioureas (for example, diphenylthiourea, triethylthiourea, N-ethyl-N ′-(4-methyl-2-thiazolyl) thiourea, carboxymethyltrimethylthiourea), thioamides (Eg, thioacetamide), rhodanines (eg, diethyl rhodanine, 5-benzylidene-N-ethyl rhodanine), phosphine sulfides (eg, trimethylphosphine sulfide), thiohydantoins, 4-oxo-oxazolidin-2 Known sulfur compounds such as -thiones, disulfides or polysulfides (for example, dimorpholine disulfide, cystine, hexathiocanthion), polythionate, elemental sulfur, and active gelatin can also be used. Particularly preferred are thiosulfates, thioureas and rhodanines.
[0038]
In selenium sensitization, unstable selenium compounds are used, and Japanese Patent Publication Nos. 43-13489, 44-15748, JP-A-4-25832, JP-A-4-109340, JP-A-4-271341, and JP-A-5-40324. No. 5-11385, Japanese Patent Application No. Hei 4-202415, No. 4-330495, No. 4-333030, No. 5-4203, No. 5-4204, No. 5-106977, No. 5-236538. Selenium compounds described in JP-A-5-241642 and JP-A-5-286916 can be used.
[0039]
Specifically, colloidal metal selenium, selenoureas (eg, N, N-dimethylselenourea, trifluoromethylcarbonyl-trimethylselenourea, acetyl-trimethylselenourea), selenoamides (eg, selenoamide, N, N-diethyl) Phenylselenoamide), phosphine selenides (eg, triphenylphosphine selenide, pentafluorophenyl-triphenylphosphine selenide), selenophosphates (eg, tri-p-tolylselenophosphate, tri-n) -Butylselenophosphate), selenoketones (for example, selenobenzophenone), isoselenocyanates, selenocarboxylic acids, selenoesters, diacyl selenides and the like may be used. Furthermore, non-labile selenium compounds described in JP-B Nos. 46-4553 and 52-34492, such as selenite, selenocyanate, selenazoles, and selenides can also be used. In particular, phosphine selenides, selenoureas and selenocyanates are preferred.
[0040]
In tellurium sensitization, an unstable tellurium compound is used, and JP-A-4-224595, JP-A-4-271341, JP-A-4-3333043, JP-A-5-303157, JP-A-6-27573, JP-A-6-175258, The unstable tellurium described in JP-A-6-180478, JP-A-6-208186, JP-A-6-208184, JP-A-6-317867, JP-A-7-140579, JP-A-7-301879, JP-A-7-301880, etc. A compound can be used.
[0041]
Specifically, phosphine tellurides (for example, butyl-diisopropylphosphine telluride, tributylphosphine telluride, tributoxyphosphine telluride, ethoxydiphenylphosphine telluride), diacyl (di) tellurides ( For example, bis (diphenylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) telluride, bis (N-phenyl-N-benzylcarbamoyl) telluride, bis (ethoxycarbonyl) Telluride), telluroureas (for example, N, N′-dimethylethylenetellurourea, N, N′-diphenylethylenetellurourea) telluramides, telluroesters and the like may be used. In particular, diacyl (di) tellurides and phosphine tellurides are preferable. Particularly, compounds described in literatures described in paragraph No. 0030 of JP-A-11-65021, general formula (II) in JP-A-5-313284, Compounds represented by (III) and (IV) are more preferred.
[0042]
Particularly, in the chalcogen sensitization of the present invention, selenium sensitization and tellurium sensitization are preferable, and tellurium sensitization is particularly preferable.
[0043]
In gold sensitization, P.I. Gold sensitizers described by Grafkides, Chimie et Physique Photographic (published by Paul Momtel, 1987, 5th edition), Research Disclosure 307, No. 307105 can be used. Specifically, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide and the like, in addition to these, U.S. Pat. Nos. 2,642,361, 5,049,484, 5,049,485, 5,169,751, Gold compounds described in 5252455, Belgian Patent No. 691857 and the like can also be used. P. Other than gold, such as platinum, palladium, and iridium salts described in Grafkides, Chimie et Physique, Photographic (Paul Momtel, published in 1987, 5th edition), Research Disclosure 307, 307105 I can do it.
[0044]
Although gold sensitization can be used alone, it is preferably used in combination with the chalcogen sensitization described above. Specifically, gold sulfur sensitization, gold selenium sensitization, gold tellurium sensitization, gold sulfur selenium sensitization, gold sulfur tellurium sensitization, gold selenium tellurium sensitization, and gold sulfur selenium tellurium sensitization.
[0045]
In the present invention, chemical sensitization can be performed at any time after particle formation and before coating. After desalting, (1) before spectral sensitization, (2) simultaneously with spectral sensitization, (3) spectral After sensitization, there may be (4) immediately before application.
[0046]
The amount of chalcogen sensitizer used in the present invention varies depending on the silver halide grains used, chemical ripening conditions, etc., but is 10 per mole of silver halide.^-8-10^-1Moles, preferably 10^-7-10^-2Use about moles.
Similarly, the amount of the gold sensitizer used in the present invention varies depending on various conditions, but as a guideline, it is 10 per silver halide.^-7Mol-10^-2Mole, more preferably 10^-6Mol ~ 5 × 10^-3Is a mole. The environmental conditions for chemically sensitizing this emulsion can be selected under any conditions, but the pAg is 8 or less, preferably 7.0 or less to 6.5 or less, particularly 6.0 or less, and the pAg is 1.5 or less. Above, preferably 2.0 or more, particularly preferably 2.5 or more, pH is 3 to 10, preferably 4 to 9, temperature is 20 to 95 ° C., preferably about 25 to 80 ° C. is there.
[0047]
In the present invention, reduction sensitization can be used in combination with chalcogen sensitization or gold sensitization. In particular, it is preferably used in combination with chalcogen sensitization.
As specific compounds for reduction sensitization, ascorbic acid, thiourea dioxide, and dimethylamine borane are preferable. In addition, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. It is preferable to use it. The reduction sensitizer may be added at any stage in the photosensitive emulsion production process from crystal growth to the preparation process immediately before coating. Further, reduction sensitization is also preferable by ripening while maintaining the pH of the emulsion at 8 or more or pAg at 4 or less, and reduction sensitization is performed by introducing a single addition portion of silver ions during grain formation. Is also preferable.
The amount of reduction sensitizer added varies depending on various conditions, but as a guideline it is 10 per silver halide.^-7Mol-10^-1Mole, more preferably 10^-6Mol ~ 5 × 10^-2Is a mole.
[0048]
A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by the method shown in European Patent Publication No. 293,917.
The photosensitive silver halide grains in the invention are preferably chemically sensitized by at least one of gold sensitization and chalcogen sensitization from the viewpoint of designing a high-sensitivity photothermographic material.
[0049]
9) Sensitizing dye
As a sensitizing dye that can be applied to the present invention, it can spectrally sensitize silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and has a spectral sensitivity suitable for the spectral characteristics of the exposure light source. The dye can be advantageously selected. The photothermographic material of the present invention is preferably spectrally sensitized so as to have a spectral sensitivity peak at 600 nm to 900 nm, or 300 nm to 500 nm. Regarding the sensitizing dye and the addition method, paragraphs 0103 to 0109 of JP-A No. 11-65021, compounds represented by the general formula (II) of JP-A No. 10-186572, and general formulas (I of JP-A No. 11-119374) ) And the dyes described in paragraph No. 0106, US Pat. Nos. 5,510,236 and 3,871,887, Example 5, JP-A-2-96131, JP-A-59-48753 Dyes disclosed in Japanese Patent No. 2000-83865, Japanese Patent Application No. 2000-86865, Japanese Patent Application No. 2000-102560, Japanese Patent Application No. 2000-205399, etc. It is described in. These sensitizing dyes may be used alone or in combination of two or more.
[0050]
The addition amount of the sensitizing dye in the present invention can be set to a desired amount in accordance with the sensitivity and the fogging performance, but is 10 per mol of silver halide in the photosensitive layer.^-6~ 1 mol is preferred, more preferably 10^-4-10^-1Is a mole.
[0051]
In the present invention, a supersensitizer can be used to improve spectral sensitization efficiency.
As the supersensitizer used in the present invention, European Patent Publication No. 587,338, US Pat. Nos. 3,877,943, 4,873,184, JP-A-5-341432, 11- 109547, 10-111543, etc. are mentioned.
[0052]
10) Combined use of silver halide
The photosensitive silver halide emulsion in the photothermographic material used in the present invention may be one kind or two or more kinds (for example, those having different average grain sizes, those having different halogen compositions, those having different crystal habits, Different chemical sensitization conditions or different metal dopes may be used in combination. The gradation can be adjusted by using a plurality of types of photosensitive silver halides having different sensitivities. Examples of these technologies include JP-A-57-119341, 53-106125, 47-3929, 48-55730, 46-5187, 50-73627, 57-150841 and the like. Can be mentioned. The sensitivity difference is preferably 0.2 log E or more for each emulsion.
[0053]
11) Mixing of silver halide and organic silver salt
It is particularly preferred that the photosensitive silver halide grains of the present invention are formed in the absence of non-photosensitive organic silver salt and chemically sensitized. This is because sufficient sensitivity may not be achieved by the method of forming silver halide by adding a halogenating agent to the organic silver salt.
As a method of mixing silver halide and organic silver salt, a method of mixing separately prepared photosensitive silver halide and organic silver salt with a high speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. Alternatively, there may be mentioned a method of preparing an organic silver salt by mixing photosensitive silver halide which has been prepared at any timing during the preparation of the organic silver salt. In any method, the effects of the present invention can be preferably obtained.
[0054]
12) Mixing silver halide into coating solution
The preferred addition timing of the silver halide of the present invention to the image forming layer coating solution is from 180 minutes before coating to immediately before, preferably from 60 minutes to 10 seconds before coating. There is no particular limitation as long as the effect is sufficiently exhibited. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's Koji Takahashi "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).
[0055]
1-1-2. Description of organic silver salt
The non-photosensitive organic silver salt used in the present invention is relatively stable to light, but when heated to 80 ° C. or higher in the presence of exposed photosensitive silver halide and a reducing agent. A silver salt that forms a silver image. The organic silver salt may be any organic material containing a source capable of reducing silver ions. As for such non-photosensitive organic silver salt, paragraph numbers 0048 to 0049 of JP-A-10-62899, page 18 line 24 to page 19 line 37 of European Patent Publication No. 0803764A1, European Patent Publication. No. 0968212A1, JP-A-11-349591, JP-A-2000-7683, JP-A-2000-72711, and the like. Silver salts of organic acids, particularly silver salts of long-chain aliphatic carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Preferable examples of the organic silver salt include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, and a mixture thereof. In the present invention, among these organic silver salts, it is preferable to use organic acid silver having a silver behenate content of 50 mol% to 100 mol%. In particular, the silver behenate content is preferably 75 mol% or more and 98 mol% or less.
[0056]
The shape of the organic silver salt that can be used in the present invention is not particularly limited, and may be a needle shape, a rod shape, a flat plate shape, or a flake shape.
In the present invention, scaly organic silver salts are preferred. In the present specification, the scaly organic silver salt is defined as follows. The organic silver salt is observed with an electron microscope, the shape of the organic silver salt particle is approximated to a rectangular parallelepiped, and the sides of the rectangular parallelepiped are defined as a, b, and c from the shortest side (even though c is the same as b) Good)), and calculate with the shorter numbers a and b, and find x as follows.
x = b / a
[0057]
In this way, x is obtained for about 200 particles, and when the average value x (average) is obtained, particles satisfying the relationship of x (average) ≧ 1.5 are defined as flakes. Preferably, 30 ≧ x (average) ≧ 1.5, more preferably 15 ≧ x (average) ≧ 1.5. Incidentally, the needle shape is 1 ≦ x (average) <1.5.
[0058]
In the flake shaped particle, a can be regarded as a thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably 0.01 μm or more and 0.3 μm or less, and more preferably 0.1 μm or more and 0.23 μm or less. The average of c / b is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and particularly preferably 1 or more and 2 or less.
[0059]
The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion is preferably 100% or less, more preferably 80% or less, and even more preferably 50% of the value obtained by dividing the standard deviation of the lengths of the short and long axes by the short and long axes. Indicates the following. The method for measuring the shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring monodispersity, there is a method of obtaining from the standard deviation of the volume weighted average diameter of the organic silver salt, and the percentage (variation coefficient) of the value divided by the volume weighted average diameter is preferably 100% or less, more Preferably it is 80% or less, More preferably, it is 50% or less. As a measuring method, for example, it is obtained from the particle size (volume weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with laser light and obtaining an autocorrelation function with respect to the temporal change of the fluctuation of the scattered light. Can do.
[0060]
Known methods and the like can be applied to the production and dispersion method of the organic acid silver used in the present invention. For example, Japanese Patent Application Laid-Open No. 10-62899, European Patent Publication No. 0803763A1, European Patent Publication No. 0968212A1, Japanese Patent Application Laid-Open No. 11-349591, Japanese Patent Application Laid-Open No. 2000-7683, Japanese Patent Application Laid-Open No. JP-A-2001-163889-90, JP-A-11-203413, Japanese Patent Application Nos. 2000-90093, 2000-195621, 2000-191226, 2000-213813, 2000-214155, 2000-. Reference may be made to 191226 and the like.
[0061]
In the present invention, an organic silver salt aqueous dispersion and a photosensitive silver salt aqueous dispersion can be mixed to produce a photosensitive material. Mixing two or more organic silver salt water dispersions and two or more photosensitive silver salt water dispersions when mixing is a method preferably used for adjusting photographic properties.
[0062]
The organic silver salt of the present invention can be used in a desired amount, but the amount of silver is 0.1 to 5 g / m.²Is more preferable, and more preferably 1 to 3 g / m.²It is. Particularly preferably 1.2 to 2.5 g / m²It is.
[0063]
1-1-3. Reducing agent
The photothermographic material of the present invention contains a reducing agent for organic silver salt. The reducing agent may be any substance (preferably an organic substance) that can reduce silver ions to metallic silver. Examples of the reducing agent are disclosed in JP-A No. 11-65021, paragraph numbers 0043 to 0045, European Patent No. 0803764, p. 7, lines 34-p. 18th and 12th lines.
[0064]
A preferable reducing agent used in the present invention is a so-called hindered phenol reducing agent having a substituent at the ortho position of the phenolic hydroxyl group, or a bisphenol reducing agent. Particularly preferred are compounds represented by the following general formula (R).
[0065]
General formula (R)
[Chemical 1]

[0066]
In general formula (R), R¹¹And R¹¹Each independently represents an alkyl group having 1 to 20 carbon atoms. R¹²And R¹²Each independently represents a hydrogen atom or a substituent that can be substituted on the benzene ring. L is a -S- group or -CHR.¹³-Represents a group. R¹³Represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. X¹And X¹Each independently represents a hydrogen atom or a group capable of substituting for a benzene ring.
[0067]
Each substituent will be described in detail.
1) R¹¹And R¹¹’
R¹¹And R¹¹Each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and the substituent of the alkyl group is not particularly limited, but is preferably an aryl group, a hydroxy group, an alkoxy group, an aryloxy group. Group, alkylthio group, arylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, acyl group, carbamoyl group, ester group, halogen atom and the like.
[0068]
2) R¹²And R¹²', X¹And X¹’
R¹²And R¹²Each independently represents a hydrogen atom or a group capable of substituting for a benzene ring.
X¹And X¹Each independently represents a hydrogen atom or a group capable of substituting for a benzene ring. Preferred examples of each group that can be substituted on the benzene ring include an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acylamino group.
[0069]
3) L
L is a -S- group or -CHR.¹³-Represents a group. R¹³Represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and the alkyl group may have a substituent.
R¹³Specific examples of the unsubstituted alkyl group include methyl group, ethyl group, propyl group, butyl group, heptyl group, undecyl group, isopropyl group, 1-ethylpentyl group, 2,4,4-trimethylpentyl group and the like. .
[0070]
Examples of substituents for alkyl groups are R¹¹In the same manner as the above substituent, a halogen atom, an alkoxy group, an alkylthio group, an aryloxy group, an arylthio group, an acylamino group, a sulfonamide group, a sulfonyl group, a phosphoryl group, an oxycarbonyl group, a carbamoyl group, a sulfamoyl group and the like can be mentioned.
[0071]
4) Preferred substituents
R¹¹And R¹¹'Is preferably a secondary or tertiary alkyl group having 3 to 15 carbon atoms, specifically, isopropyl group, isobutyl group, t-butyl group, t-amyl group, t-octyl group, cyclohexyl group, cyclopentyl. Group, 1-methylcyclohexyl group, 1-methylcyclopropyl group and the like. R¹¹And R¹¹'Is more preferably a tertiary alkyl group having 4 to 12 carbon atoms, among which a t-butyl group, a t-amyl group, and a 1-methylcyclohexyl group are more preferable, and a t-butyl group is most preferable.
[0072]
R¹²And R¹²'Is preferably an alkyl group having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, isopropyl group, t-butyl group, t-amyl group, cyclohexyl group, 1-methyl group. Examples include cyclohexyl group, benzyl group, methoxymethyl group, methoxyethyl group and the like. More preferred are methyl group, ethyl group, propyl group, isopropyl group and t-butyl group.
[0073]
X¹And X¹'Is preferably a hydrogen atom, a halogen atom or an alkyl group, more preferably a hydrogen atom.
[0074]
L is preferably -CHR¹³-Group.
[0075]
R¹³Is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or a 2,4,4-trimethylpentyl group. R¹³Particularly preferred is a hydrogen atom, a methyl group, a propyl group or an isopropyl group.
[0076]
R¹³R is a hydrogen atom, R¹²And R¹²'Is preferably an alkyl group having 2 to 5 carbon atoms, more preferably an ethyl group or a propyl group, and most preferably an ethyl group.
[0077]
R¹³Is a primary or secondary alkyl group having 1 to 8 carbon atoms, R¹²And R¹²'Is preferably a methyl group. R¹³The primary or secondary alkyl group having 1 to 8 carbon atoms is preferably a methyl group, an ethyl group, a propyl group or an isopropyl group, more preferably a methyl group, an ethyl group or a propyl group.
[0078]
R¹¹, R¹¹'And R¹², R¹²When both are methyl groups,¹³Is preferably a secondary alkyl group. In this case, R¹³As the secondary alkyl group, isopropyl group, isobutyl group, and 1-ethylpentyl group are preferable, and isopropyl group is more preferable.
[0079]
The reducing agent is R¹¹, R¹¹'And R¹²And R¹²'And R¹³Depending on the combination, various heat development performances differ. Since these heat development performances can be adjusted by using two or more reducing agents in combination at various mixing ratios, it is preferable to use two or more reducing agents in combination depending on the purpose.
[0080]
Specific examples of the compound represented by the general formula (R) of the present invention are shown below, but the present invention is not limited thereto.
[0081]
[Chemical 2]

[0082]
[Chemical 3]

[0083]
[Formula 4]

[0084]
Particularly preferred are compounds as shown in (R-1) to (R-20).
[0085]
In the present invention, the reducing agent is added in an amount of 0.01 to 5.0 g / m.²Is preferably 0.1 to 3.0 g / m.²More preferably, it is contained in an amount of 5 to 50% by mole, more preferably 10 to 40% by mole based on 1 mole of silver on the surface having the image forming layer.
[0086]
The reducing agent of the present invention can be added to an image forming layer containing an organic silver salt and a photosensitive silver halide and its adjacent layer, but it is more preferably contained in the image forming layer.
[0087]
The reducing agent of the present invention may be contained in the coating solution by any method such as a solution form, an emulsified dispersion form, or a solid fine particle dispersion form, and may be contained in the photosensitive material.
[0088]
Well-known emulsifying dispersion methods include dissolving oil using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically emulsifying the dispersion. The method of producing is mentioned.
[0089]
The solid fine particle dispersion method includes a method in which a reducing agent is dispersed in an appropriate solvent such as water by a ball mill, a colloid mill, a vibration ball mill, a sand mill, a jet mill, a roller mill, or an ultrasonic wave to create a solid dispersion. Can be mentioned. A dispersion method using a sand mill is preferable. In this case, a protective colloid (for example, polyvinyl alcohol) or a surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three isopropyl groups having different substitution positions)) may be used. Good. The aqueous dispersion can contain a preservative (eg, benzoisothiazolinone sodium salt).
[0090]
Particularly preferable is a solid particle dispersion method of a reducing agent, and it is preferable to add fine particles having an average particle size of 0.01 μm to 10 μm, preferably 0.05 μm to 5 μm, more preferably 0.1 μm to 1 μm. In the present application, it is preferable to use other solid dispersions dispersed in a particle size within this range.
[0091]
1-1-4. Development accelerator
In the photothermographic material of the present invention, a sulfonamide phenol compound represented by the general formula (A) described in JP-A-2000-267222, JP-A-2000-330234, or the like is used as a development accelerator. Hindered phenol compounds represented by the general formula (II) described in No. 92075, the general formula (I) described in JP-A Nos. 10-62895 and 11-15116, and Japanese Patent Application No. 2001-074278 The hydrazine compounds represented by the general formula (1) described above and the phenolic or naphthol compounds represented by the general formula (2) described in Japanese Patent Application No. 2000-76240 are preferably used. These development accelerators are used in the range of 0.1 to 20 mol% with respect to the reducing agent, preferably in the range of 0.5 to 10 mol%, more preferably in the range of 1 to 5 mol%. The introduction method to the light-sensitive material includes the same method as the reducing agent, but it is particularly preferable to add as a solid dispersion or an emulsified dispersion. When added as an emulsified dispersion, it is added as an emulsified dispersion dispersed using a high-boiling solvent that is solid at room temperature and a low-boiling auxiliary solvent, or as a so-called oilless emulsified dispersion that does not use a high-boiling solvent. It is preferable to add.
[0092]
In the present invention, among the above development accelerators, hydrazine compounds represented by the general formula (1) described in Japanese Patent Application No. 2001-074278 and the general formula (2) described in Japanese Patent Application No. 2000-76240. A phenolic or naphtholic compound represented by the formula is particularly preferred.
[0093]
Hereinafter, although the preferable specific example of the development accelerator of this invention is given, this invention is not limited to these.
[0094]
[Chemical formula 5]

[0095]
1-1-5. Hydrogen bonding compound
In the present invention, it is preferable to use a non-reducing compound having a group capable of forming a hydrogen bond with an aromatic hydroxyl group (—OH) of the reducing agent.
[0096]
Examples of the group capable of forming a hydrogen bond include a phosphoryl group, a sulfoxide group, a sulfonyl group, a carbonyl group, an amide group, an ester group, a urethane group, a ureido group, a tertiary amino group, and a nitrogen-containing aromatic group. Among them, preferred are a phosphoryl group, a sulfoxide group, an amide group (however, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a urethane group. (However, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a ureido group (however, it has no> N—H group,> N-Ra (Ra is a substituent other than H).)
[0097]
In the present invention, particularly preferred hydrogen bonding compounds are compounds represented by the following general formula (D).
[0098]
Formula (D)
[Chemical 6]

[0099]
R in general formula (D)²¹Or R²³Each independently represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a heterocyclic group, and these groups may be unsubstituted or may have a substituent.
[0100]
R²¹Or R²³In the case where has a substituent, the substituent is a halogen atom, alkyl group, aryl group, alkoxy group, amino group, acyl group, acylamino group, alkylthio group, arylthio group, sulfonamido group, acyloxy group, oxycarbonyl group, carbamoyl Group, sulfamoyl group, sulfonyl group, phosphoryl group and the like. Preferred as substituents are alkyl groups or aryl groups such as methyl group, ethyl group, isopropyl group, t-butyl group, t-octyl group, phenyl group, 4-alkoxyphenyl group, 4-acyloxyphenyl group and the like can be mentioned.
[0101]
R²¹Or R²³Specific examples of the alkyl group include methyl group, ethyl group, butyl group, octyl group, dodecyl group, isopropyl group, t-butyl group, t-amyl group, t-octyl group, cyclohexyl group, and 1-methylcyclohexyl group. Benzyl group, phenethyl group, 2-phenoxypropyl group, and the like.
[0102]
Examples of the aryl group include phenyl group, cresyl group, xylyl group, naphthyl group, 4-t-butylphenyl group, 4-t-octylphenyl group, 4-anisidyl group, and 3,5-dichlorophenyl group.
[0103]
Alkoxy groups include methoxy, ethoxy, butoxy, octyloxy, 2-ethylhexyloxy, 3,5,5-trimethylhexyloxy, dodecyloxy, cyclohexyloxy, 4-methylcyclohexyloxy, benzyl An oxy group etc. are mentioned.
[0104]
Examples of the aryloxy group include a phenoxy group, a cresyloxy group, an isopropylphenoxy group, a 4-t-butylphenoxy group, a naphthoxy group, and a biphenyloxy group.
[0105]
Examples of the amino group include a dimethylamino group, a diethylamino group, a dibutylamino group, a dioctylamino group, an N-methyl-N-hexylamino group, a dicyclohexylamino group, a diphenylamino group, and an N-methyl-N-phenylamino group. .
[0106]
R²¹Or R²³Are preferably an alkyl group, an aryl group, an alkoxy group, or an aryloxy group. In terms of the effect of the present invention, R²¹Or R²³Of these, at least one is preferably an alkyl group or an aryl group, and more preferably two or more are an alkyl group or an aryl group. In addition, R can be obtained at low cost.²¹Or R²³Are preferably the same group.
[0107]
Specific examples of the hydrogen bonding compound including the compound of the general formula (D) in the present invention are shown below, but the present invention is not limited thereto.
[0108]
[Chemical 7]

[0109]
[Chemical 8]

[0110]
Specific examples of the hydrogen bonding compound include those described in Japanese Patent Application Nos. 2000-192191 and 2000-19481 in addition to those described above.
[0111]
The hydrogen bonding compound of the present invention can be used in a light-sensitive material after being contained in a coating solution in the form of a solution, an emulsified dispersion, or a solid dispersed fine particle dispersion in the same manner as the reducing agent. The compound of the present invention forms a complex by a hydrogen bond with a compound having a phenolic hydroxyl group in a solution state. Depending on the combination of the reducing agent and the compound of the general formula (D) of the present invention, the compound of the present invention Can be separated.
[0112]
The use of the crystal powder isolated in this way as a solid dispersed fine particle dispersion is particularly preferable for obtaining stable performance. Further, a method in which the reducing agent and the hydrogen bonding compound of the present invention are mixed as a powder and complexed at the time of dispersion with a sand grinder mill or the like using an appropriate dispersant can be preferably used.
[0113]
The hydrogen bonding compound of the present invention is preferably used in the range of 1 to 200 mol%, more preferably in the range of 10 to 150 mol%, still more preferably in the range of 30 to 100 mol% with respect to the reducing agent. It is.
[0114]
1-1-6. binder
The binder of the organic silver salt-containing layer of the present invention may be any polymer, suitable binders are transparent or translucent and generally colorless, natural resins, polymers and copolymers, synthetic resins, polymers and copolymers, other films Forming media such as gelatins, gums, poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (acrylic acid) , Poly (methyl methacrylic acid) s, poly (vinyl chloride) s, poly (methacrylic acid) s, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, Poly (vinyl acetal) s (eg, poly (vinyl acetal) Marl) and poly (vinyl butyral)), poly (esters), poly (urethane) s, phenoxy resins, poly (vinylidene chloride) s, poly (epoxides), poly (carbonates), poly (vinyl acetate) s , Poly (olefin) s, cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or emulsion.
[0115]
In the present invention, the glass transition temperature of the binder of the layer containing the organic silver salt is preferably 10 ° C. or higher and 80 ° C. or lower, more preferably 20 ° C. to 70 ° C., and 23 ° C. or higher and 65 ° C. or lower. More preferably.
[0116]
In this specification, Tg is calculated by the following formula.
1 / Tg = Σ (Xi / Tgi)
[0117]
Here, it is assumed that n monomer components from i = 1 to n are copolymerized in the polymer. Xi is the weight fraction of the i-th monomer (ΣXi = 1), and Tgi is the glass transition temperature (absolute temperature) of the homopolymer of the i-th monomer. However, Σ is the sum from i = 1 to n.
As the transition temperature value (Tgi) of the homopolymer glass of each monomer, the value of Polymer Handbook (3rd Edition) (by J. Brandrup, EH Immergut (Wiley-Interscience, 1989)) was adopted.
[0118]
The polymer used as the binder may be used alone or in combination of two or more as required. Further, a glass transition temperature of 20 ° C. or higher and a glass transition temperature of less than 20 ° C. may be used in combination. When two or more kinds of polymers having different Tg are blended and used, the weight average Tg is preferably within the above range.
[0119]
In the present invention, when the organic silver salt-containing layer is formed using a coating solution in which 30% by mass or more of the solvent is water and dried, the binder of the organic silver salt-containing layer is further an aqueous solvent ( When it is soluble or dispersible in an aqueous solvent), the performance is improved particularly when it is made of a latex of a polymer having an equilibrium moisture content of 2% by mass or less at 25 ° C. and 60% RH.
The most preferable form is one prepared so that the ionic conductivity is 2.5 mS / cm or less, and as such a preparation method, there is a method of performing purification treatment using a separation functional membrane after polymer synthesis.
[0120]
The aqueous solvent in which the polymer is soluble or dispersible here is a mixture of water or water and 70% by mass or less of a water-miscible organic solvent.
Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, ethyl acetate and dimethylformamide.
[0121]
The “equilibrium moisture content at 25 ° C. and 60% RH” is the following using the weight W1 of the polymer in the humidity-controlled equilibrium under the atmosphere of 25 ° C. and 60% RH and the weight W0 of the polymer in the absolutely dry state at 25 ° C. It can be expressed as
Equilibrium moisture content at 25 ° C. and 60% RH = [(W1−W0) / W0] × 100 (mass%) For the definition and measurement method of moisture content, see, for example, Polymer Engineering Laboratory 14, Polymer Material Testing Method (polymer (Journal of academic society, Jinjinshokan).
[0122]
The equilibrium moisture content at 25 ° C. and 60% RH of the binder polymer of the present invention is preferably 2% by mass or less, more preferably 0.01% by mass or more and 1.5% by mass or less, and further preferably 0.02% by mass. % To 1% by mass is desirable.
[0123]
The binder of the present invention is particularly preferably a polymer that can be dispersed in an aqueous solvent. Examples of the dispersed state include latex in which fine particles of water-insoluble hydrophobic polymer are dispersed and polymer molecules dispersed in a molecular state or forming micelles, and all are preferable. The average particle size of the dispersed particles is preferably 1 to 50000 nm, more preferably about 5 to 1000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.
[0124]
In the present invention, preferred embodiments of the polymer that can be dispersed in an aqueous solvent include acrylic polymers, poly (esters), rubbers (eg, SBR resin), poly (urethanes), poly (vinyl chloride) s, poly (acetic acid). Hydrophobic polymers such as vinyl), poly (vinylidene chloride) and poly (olefin) can be preferably used. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or copolymers obtained by polymerizing two or more types of monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer.
[0125]
These polymers have a number average molecular weight of 5,000 to 1,000,000, preferably 10,000 to 200,000. When the molecular weight is too small, the mechanical strength of the emulsion layer is insufficient, and when the molecular weight is too large, the film formability is poor, which is not preferable.
[0126]
Specific examples of preferable polymer latex include the following. Below, it represents using a raw material monomer, the numerical value in a parenthesis is the mass%, and molecular weight is a number average molecular weight. When a polyfunctional monomer was used, the concept of molecular weight was not applicable because a crosslinked structure was formed, so it was described as crosslinkability, and the description of molecular weight was omitted. Tg represents the glass transition temperature.
[0127]
Latex of P-1; -MMA (70) -EA (27) -MAA (3)-(molecular weight 37000, Tg 61 ° C.)
Latex of P-2; -MMA (70) -2EHA (20) -St (5) -AA (5)-(molecular weight 40000, Tg 59 ° C.)
P-3; latex of -St (50) -Bu (47) -MAA (3)-(crosslinkability, Tg-17 ° C)
Latex of P-4; -St (68) -Bu (29) -AA (3)-(crosslinkability, Tg 17 ° C.)
Latex of P-5; -St (71) -Bu (26) -AA (3)-(crosslinkability, Tg 24 ° C.)
Latex of P-6; -St (70) -Bu (27) -IA (3)-(crosslinkability)
Latex of P-7; -St (75) -Bu (24) -AA (1)-(crosslinkability, Tg 29 ° C.)
Latex (crosslinkability) of P-8; -St (60) -Bu (35) -DVB (3) -MAA (2)-
Latex (crosslinkability) of P-9; -St (70) -Bu (25) -DVB (2) -AA (3)-
P-10; latex of VC (50) -MMA (20) -EA (20) -AN (5) -AA (5)-(molecular weight 80000)
P-11; latex of VDC (85) -MMA (5) -EA (5) -MAA (5)-(molecular weight 67000)
Latex of P-12; -Et (90) -MAA (10)-(molecular weight 12000)
P-13; Latex of -St (70) -2EHA (27) -AA (3) (molecular weight 130000, Tg 43 ° C)
P-14; latex of MMA (63) -EA (35) -AA (2) (molecular weight 33000, Tg 47 ° C.)
Latex of P-15; -St (70.5) -Bu (26.5) -AA (3)-(crosslinkability, Tg 23 ° C.)
Latex of P-16; -St (69.5) -Bu (27.5) -AA (3)-(crosslinkability, Tg 20.5 ° C)
[0128]
The abbreviations for the above structures represent the following monomers. MMA; Methyl methacrylate, EA; Ethyl acrylate, MAA; Methacrylic acid, 2EHA; 2-Ethylhexyl acrylate, St; Styrene, Bu; Butadiene, AA; Acrylic acid, DVB; Divinylbenzene, VC; Vinyl chloride, AN; Acrylonitrile, VDC Vinylidene chloride, Et; ethylene, IA; itaconic acid.
[0129]
The polymer latex described above is also commercially available, and the following polymers can be used. Examples of acrylic polymers include Sebian A-4635, 4718, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.), poly ( Examples of esters) include: FINETEX ES650, 611, 675, 850 (manufactured by Dainippon Ink & Chemicals, Inc.), WD-size, WMS (manufactured by Eastman Chemical), and other examples of poly (urethanes). Examples of rubbers such as HYDRAN AP10, 20, 30, 40 (above Dainippon Ink Chemical Co., Ltd.) include LACSTAR 7310K, 3307B, 4700H, 7132C (above Dainippon Ink Chemical Co., Ltd.), Nipol Lx416, 410, 438C, 2507 (above ZEON CORPORATION) Examples of poly (vinyl chloride) are G351 and G576 (manufactured by Nippon Zeon Co., Ltd.), and examples of poly (vinylidene chloride) are L502 and L513 (manufactured by Asahi Kasei Kogyo Co., Ltd.). Examples of poly (olefin) s include Chemipearl S120, SA100 (manufactured by Mitsui Petrochemical Co., Ltd.).
These polymer latexes may be used alone or in combination of two or more as required.
[0130]
As the polymer latex used in the present invention, a styrene-butadiene copolymer latex is particularly preferable. The weight ratio of the styrene monomer unit to the butadiene monomer unit in the styrene-butadiene copolymer is preferably 40:60 to 95: 5. The proportion of the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably 60 to 99% by mass. The preferred molecular weight range is the same as described above.
[0131]
Examples of latexes of styrene-butadiene copolymer that are preferably used in the present invention include P-3 to P-8, 14, and 15 described above, commercially available LACSTAR-3307B and 7132C, Nipol Lx416, and the like.
[0132]
If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose may be added to the organic silver salt-containing layer of the light-sensitive material of the present invention.
[0133]
The amount of these hydrophilic polymers added is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total binder of the organic silver salt-containing layer.
[0134]
The organic silver salt-containing layer (that is, the image forming layer) of the present invention is preferably formed using a polymer latex as a binder. The amount of the binder in the organic silver salt-containing layer is preferably such that the weight ratio of total binder / organic silver salt is 1/10 to 10/1, more preferably 1/5 to 4/1.
[0135]
In addition, such an organic silver salt-containing layer is usually a photosensitive layer (emulsion layer) containing a photosensitive silver halide which is a photosensitive silver salt. The weight ratio of silver is preferably 400-5, more preferably 200-10.
[0136]
The total binder amount of the image forming layer of the present invention is 0.2 to 30 g / m.², More preferably 1-15 g / m²The range of is preferable. The image forming layer of the present invention may contain a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like.
[0137]
In the present invention, the solvent of the organic silver salt-containing layer coating solution of the light-sensitive material (here, for simplicity, the solvent and the dispersion medium are collectively referred to as a solvent) is preferably an aqueous solvent containing 30% by mass or more of water. As a component other than water, any water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate may be used. The water content of the solvent is more preferably 50% by mass or more, and still more preferably 70% by mass or more.
[0138]
Specific examples of the preferred solvent composition include water 100, water / methyl alcohol = 90/10, water / methyl alcohol = 70/30, water / methyl alcohol / dimethylformamide = 80/15/5, water / methyl. Alcohol / ethyl cellosolve = 85/10/5, water / methyl alcohol / isopropyl alcohol = 85/10/5, etc. (numerical values are mass%).
[0139]
1-1-7. Antifogging agent
The present invention preferably contains a compound represented by the following general formula (H) as an antifoggant.
[0140]
General formula (H) Q- (Y) n-C (Z₁) (Z₂) X
[0141]
In the general formula (H), Q represents an alkyl group, an aryl group or a heterocyclic group, Y represents a divalent linking group, n represents 0 or 1, Z₁And Z₂Represents a halogen atom, and X represents a hydrogen atom or an electron withdrawing group.
[0142]
Q preferably represents a phenyl group substituted with an electron-withdrawing group in which Hammett's substituent constant σp takes a positive value. Regarding Hammett's substituent constants, Journal of Medicinal Chemistry, 1973, Vol. 16, no. 11, 1207-1216 etc. can be referred to.
[0143]
Examples of such an electron withdrawing group include a halogen atom (fluorine atom (σp value: 0.06), chlorine atom (σp value: 0.23), bromine atom (σp value: 0.23), iodine atom. (Σp value: 0.18)), trihalomethyl group (tribromomethyl (σp value: 0.29), trichloromethyl (σp value: 0.33), trifluoromethyl (σp value: 0.54)), Cyano group (σp value: 0.66), nitro group (σp value: 0.78), aliphatic aryl, or heterocyclic sulfonyl group (for example, methanesulfonyl (σp value: 0.72)), aliphatic aryl Or a heterocyclic acyl group (for example, acetyl (σp value: 0.50), benzoyl (σp value: 0.43)), alkynyl group (for example, C≡CH (σp value: 0.23)), aliphatic Aryl or heterocyclic oxycarbo Group (for example, methoxycarbonyl (σp value: 0.45), phenoxycarbonyl (σp value: 0.44)), carbamoyl group (σp value: 0.36), sulfamoyl group (σp value: 0.57), Examples thereof include a sulfoxide group, a heterocyclic group, and a phosphoryl group.
The σp value is preferably in the range of 0.2 to 2.0, more preferably in the range of 0.4 to 1.0.
[0144]
Preferred as the electron withdrawing group are a carbamoyl group, an alkoxycarbonyl group, an alkylsulfonyl group, an alkylphosphoryl group, a carboxyl group, an alkyl or arylcarbonyl group, and an arylsulfonyl group, and particularly preferably a carbamoyl group and an alkoxycarbonyl group. , An alkylsulfonyl group and an alkylphosphoryl group, and a carbamoyl group is most preferred.
[0145]
X is preferably an electron-withdrawing group, more preferably a halogen atom, aliphatic / aryl or heterocyclic sulfonyl group, aliphatic / aryl or heterocyclic acyl group, aliphatic / aryl or heterocyclic oxycarbonyl group, A carbamoyl group and a sulfamoyl group, particularly preferably a halogen atom.
Among the halogen atoms, a chlorine atom, a bromine atom and an iodine atom are preferable, a chlorine atom and a bromine atom are more preferable, and a bromine atom is particularly preferable.
[0146]
Y is preferably -C (= O)-, -SO- or -SO.₂-, More preferably -C (= O)-, -SO₂-, Particularly preferably -SO₂-. n represents 0 or 1, and is preferably 1.
[0147]
Although the specific example of the compound of general formula (H) of this invention is shown below, this invention is not limited to these.
[0148]
[Chemical 9]

[0149]
Embedded image

[0150]
The compound represented by the general formula (H) of the present invention is 10 per mole of the non-photosensitive silver salt of the image forming layer.^-4It is preferable to use in the range of ~ 0.8 mol, more preferably 10^-3In the range of ~ 0.1 mol, more preferably 5 × 10^-3It is preferable to use in the range of ˜0.05 mol.
In particular, when a silver halide having a high silver iodide content according to the present invention is used, the addition amount of the compound of the general formula (H) is important in order to obtain a sufficient antifogging effect. 10^-3Most preferably, it is used in the range of ˜0.03 mol.
[0151]
In the present invention, examples of the method for incorporating the compound represented by the general formula (H) into the photosensitive material include the methods described in the method for containing a reducing agent.
[0152]
The melting point of the compound represented by the general formula (H) is preferably 200 ° C. or lower, more preferably 170 ° C. or lower.
[0153]
Other organic polyhalides used in the present invention include those disclosed in the patents described in paragraph Nos. 0111 to 0112 of JP-A No. 11-65021. In particular, an organic halogen compound represented by the formula (P) of Japanese Patent Application No. 11-87297, an organic polyhalogen compound represented by the general formula (II) of Japanese Patent Application Laid-Open No. 10-339934, and Japanese Patent Application No. 11-205330 The organic polyhalogen compounds described are preferred.
[0154]
1-1-8. Other antifoggants
Examples of other antifoggants include mercury (II) salts described in paragraph No. 0113 of JP-A No. 11-65021, benzoic acids of paragraph No. 0114 of the same, salicylic acid derivatives disclosed in JP-A No. 2000-206642, and formulas described in JP-A No. 2000-221634. A formalin scavenger compound represented by (S), a triazine compound according to claim 9 of JP-A-11-352624, a compound represented by formula (III) of JP-A-6-11791, 4-hydroxy-6-6 And methyl-1,3,3a, 7-tetrazaindene and the like.
[0155]
Antifoggant, stabilizer and stabilizer precursor that can be used in the present invention described in paragraph No. 0070 of JP-A-10-62899, page 20, line 57 to page 21, line 7 of European Patent No. 0803764A1 Patented compounds and compounds described in JP-A Nos. 9-281737 and 9-329864 can be mentioned.
[0156]
The photothermographic material in the invention may contain an azolium salt for the purpose of fog prevention. Examples of the azolium salt include compounds represented by general formula (XI) described in JP-A-59-193447, compounds described in JP-B-55-12581, and general formula (II) described in JP-A-60-153039. And the compounds represented. The azolium salt may be added to any part of the photosensitive material, but the addition layer is preferably added to the layer having the photosensitive layer, and more preferably to the organic silver salt-containing layer.
[0157]
The azolium salt may be added at any step in the coating solution preparation. When added to the organic silver salt-containing layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be used. To immediately before coating. The azolium salt may be added by any method such as powder, solution, fine particle dispersion. Moreover, you may add as a solution mixed with other additives, such as a sensitizing dye, a reducing agent, and a color toning agent.
[0158]
In the present invention, any amount of the azolium salt may be added, but 1 × 10 10 per silver mole.^-6Preferred is 1 mol or more and 2 mol or less.^-3More preferably, it is more than mol and less than 0.5 mol.
[0159]
1-1-9. Other additives
1) Mercapto, disulfide, and thiones
In the present invention, a mercapto compound, a disulfide compound, and a thione compound can be contained in order to suppress or promote development to control development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. JP-A-10-62899, Paragraph Nos. 0067 to 0069, JP-A-10-186572, General Formula (I) and specific examples thereof include Paragraph Nos. 0033 to 0052, European Patent Publication No. 0803764A1 20 pages, lines 36 to 56, and Japanese Patent Application No. 11-273670. Of these, mercapto-substituted heteroaromatic compounds are preferred.
[0160]
2) Color preparation
In the photothermographic material of the present invention, it is preferable to add a color toning agent. For the color toning agent, paragraph numbers 0054 to 0055 of JP-A No. 10-62899, p. Lines 21, 23 to 48, JP-A No. 2000-356317 and Japanese Patent Application No. 2000-187298, in particular, phthalazinones (phthalazinone, phthalazinone derivatives or metal salts; for example, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione); phthalazinones and phthalic acids (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, A combination of diammonium phthalate, sodium phthalate, potassium phthalate and tetrachlorophthalic anhydride); phthalazines (phthalazine, phthalazine derivatives or metal salts; for example, 4- (1-naphthyl) phthalazine, 6-isopropylphthalazine, 6 -T-butylphthalazine, 6-chloro (Talazine, 5.7-dimethoxyphthalazine, and 2,3-dihydrophthalazine) are preferable. In particular, in the combination with silver halide having a high silver iodide content, the combination of phthalazine and phthalic acid is preferable.
[0161]
The amount of phthalazine added is preferably 0.01 to 0.3 mol, more preferably 0.02 to 0.2 mol, particularly preferably 0.02 to 0.1 mol, per mol of the organic silver salt. It is. This addition amount is an important factor for promoting development, which is a problem in the silver halide emulsion having a high silver iodide content of the present invention. By selecting an appropriate addition amount, both sufficient developability and low fog are achieved. Is possible.
[0162]
3) Plasticizer, lubricant
The plasticizer and lubricant that can be used in the photosensitive layer of the present invention are described in paragraph No. 0117 of JP-A No. 11-65021. The slip agent is described in JP-A No. 11-84573, paragraph numbers 0061 to 0064 and Japanese Patent Application No. 11-106881, paragraph numbers 0049 to 0062.
[0163]
4) Dyes and pigments
The photosensitive layer of the present invention has various dyes and pigments (for example, CI Pigment Blue 60, CI Pigment Blue 64, C.I.) from the viewpoints of improving color tone, preventing interference fringes during laser exposure, and preventing irradiation. I. Pigment Blue 15: 6) can be used. These are described in detail in WO98 / 36322, JP-A-10-268465, JP-A-11-338098 and the like.
[0164]
5) Ultra-high contrast agent
In order to form an ultrahigh contrast image suitable for printing plate making applications, it is preferable to add an ultrahigh contrast agent to the image forming layer. As for the super-high contrast agent and its addition method and addition amount, the formula (H) and formulas of paragraph No. 0118 of the same publication, paragraph Nos. 0136 to 0193 of JP-A No. 11-223898, and Japanese Patent Application No. 11-87297 are disclosed. (1) to (3), compounds of formulas (A) and (B), compounds of general formulas (III) to (V) described in Japanese Patent Application No. 11-91652 (specific compounds: embedded image 24), the contrast enhancement accelerator is described in paragraph No. 0102 of JP-A No. 11-65021 and paragraph Nos. 0194 to 0195 of JP-A No. 11-223898.
[0165]
In order to use formic acid or formate as a strong fogging substance, it is preferably contained at 5 mmol or less, more preferably 1 mmol or less, per mol of silver on the side having the image forming layer containing photosensitive silver halide.
When the ultrahigh contrast agent is used in the photothermographic material of the present invention, it is preferable to use an acid formed by hydrating diphosphorus pentoxide or a salt thereof in combination. Acids or salts thereof formed by hydration of diphosphorus pentoxide include metaphosphoric acid (salt), pyrophosphoric acid (salt), orthophosphoric acid (salt), triphosphoric acid (salt), tetraphosphoric acid (salt), hexametalin An acid (salt) etc. can be mentioned. Examples of the acid or salt thereof formed by hydrating diphosphorus pentoxide particularly preferably include orthophosphoric acid (salt) and hexametaphosphoric acid (salt). Specific examples of the salt include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate, ammonium hexametaphosphate and the like.
Amount of acid or salt thereof formed by hydration of diphosphorus pentoxide (1m photosensitive material)²The coating amount per unit) may be a desired amount according to the performance such as sensitivity and fog, but 0.1 to 500 mg / m²Is preferably 0.5 to 100 mg / m²Is more preferable.
[0166]
1-1-10. Preparation and application of coating solution
The preparation temperature of the image forming layer coating solution of the present invention is preferably 30 ° C. or more and 65 ° C. or less, more preferably 35 ° C. or more and less than 60 ° C., and more preferably 35 ° C. or more and 55 ° C. or less. Moreover, it is preferable that the temperature of the image forming layer coating liquid immediately after the addition of the polymer latex is maintained at 30 ° C. or higher and 65 ° C. or lower.
[0167]
1-2. Other layers and components
The photothermographic material of the present invention can have a non-photosensitive layer in addition to the image forming layer. The non-photosensitive layer includes (a) a surface protective layer provided on the image forming layer (on the side farther than the support), (b) between the plurality of image forming layers and between the image forming layer and the protective layer. It can be classified into an intermediate layer provided therebetween, (c) an undercoat layer provided between the image forming layer and the support, and (d) a back layer provided on the opposite side of the image forming layer.
[0168]
In addition, although a layer acting as an optical filter can be provided, it is provided as the layer (a) or (b). The antihalation layer is provided on the photosensitive material as the layer (c) or (d).
[0169]
1) Surface protective layer
In the photothermographic material of the invention, a surface protective layer can be provided for the purpose of preventing adhesion of the image forming layer. The surface protective layer may be a single layer or a plurality of layers. The surface protective layer is described in JP-A No. 11-65021, paragraph numbers 0119 to 0120 and Japanese Patent Application No. 2000-171936.
[0170]
As the binder for the surface protective layer of the present invention, gelatin is preferable, but it is also preferable to use polyvinyl alcohol (PVA) or a combination thereof. As gelatin, inert gelatin (for example, Nitta gelatin 750), phthalated gelatin (for example, Nitta gelatin 801), and the like can be used.
[0171]
Examples of PVA include those described in paragraph Nos. 0009 to 0020 of JP-A No. 2000-171936. Completely saponified PVA-105, partially saponified PVA-205, PVA-335, and modified polyvinyl alcohol MP- Preferred is 203 (trade name, manufactured by Kuraray Co., Ltd.).
[0172]
Polyvinyl alcohol coating amount of protective layer (per layer) (support 1m²Per unit) as 0.3 to 4.0 g / m²Is preferable, 0.3 to 2.0 g / m²Is more preferable.
[0173]
Total binder (including water-soluble polymer and latex polymer) coating amount of surface protective layer (per layer) (support 1m)²As per) 0.3 to 5.0 g / m²Is preferable, 0.3 to 2.0 g / m²Is more preferable.
[0174]
2) Antihalation layer
In the photothermographic material of the present invention, the antihalation layer can be provided on the side far from the exposure light source with respect to the photosensitive layer. As for the antihalation layer, paragraphs 0123 to 0124 of JP-A-11-65021, JP-A-11-223898, 9-230531, 10-36695, 10-104779, 11-231457, 11 -352625, 11-352626 and the like.
[0175]
The antihalation layer contains an antihalation dye having absorption at the exposure wavelength. When the exposure wavelength is in the infrared region, an infrared absorbing dye may be used, and in that case, a dye having no absorption in the visible region is preferable.
[0176]
When antihalation is performed using a dye having absorption in the visible range, it is preferable that the dye color does not substantially remain after image formation, and a means for decoloring by the heat of heat development is used. In particular, it is preferable to add a thermally decolorable dye and a base precursor to the non-photosensitive layer to function as an antihalation layer. These techniques are described in JP-A-11-231457 and the like.
[0177]
The amount of decoloring dye added is determined by the use of the dye. In general, the optical density (absorbance) measured at the target wavelength is used in an amount exceeding 0.1. The optical density is preferably 0.2-2. The amount of dye used to obtain such an optical density is generally 0.001 to 1 g / m.²Degree.
[0178]
When the dye is decolored in this way, the optical density after heat development can be reduced to 0.1 or less. Two or more kinds of decoloring dyes may be used in combination in a heat decoloring type recording material or a photothermographic material. Similarly, two or more kinds of base precursors may be used in combination.
[0179]
In the thermal decoloration using such decoloring dye and base precursor, substances that lower the melting point by 3 ° C. or more when mixed with a base precursor as described in JP-A-11-352626 (for example, diphenylsulfone, 4-chlorophenyl, etc.) (Phenyl) sulfone) is preferably used in view of thermal decoloring properties.
[0180]
3) Back layer
The back layer applicable to the present invention is described in paragraph Nos. 0128 to 0130 of JP-A No. 11-65021.
[0181]
In the present invention, a colorant having an absorption maximum at 300 to 450 nm can be added for the purpose of improving the silver color tone and the temporal change of the image. Such colorants are disclosed in JP-A-62-210458, JP-A-63-104046, JP-A-63-103235, JP-A-63-208846, JP-A-63-306436, JP-A-63-314535, and JP-A-01-61745. And Japanese Patent Application No. 11-276751. Such colorants are typically 0.1 mg / m²~ 1g / m²The back layer provided on the opposite side of the photosensitive layer is preferable as the layer to be added in the range of.
[0182]
4) Matting agent
In the present invention, it is preferable to add a matting agent to the surface protective layer and the back layer in order to improve transportability. Matting agents are described in JP-A No. 11-65021, paragraph numbers 0126 to 0127.
Matting agent is photosensitive material 1m²When expressed in a coating amount per unit, preferably 1 to 400 mg / m², More preferably 5 to 300 mg / m²It is.
[0183]
Further, the matte degree of the emulsion surface may be any as long as a so-called stardust failure in which small white spots occur in the image area and light leakage occurs, but the Beck smoothness is preferably 30 seconds or more and 2000 seconds or less. It is preferably 40 seconds or more and 1500 seconds or less. The Beck smoothness can be easily determined by Japanese Industrial Standard (JIS) P8119 "Smoothness test method using Beck tester for paper and paperboard" and TAPPI standard method T479.
[0184]
In the present invention, the matte degree of the back layer is preferably a Beck smoothness of 1200 seconds or less and 10 seconds or more, preferably 800 seconds or less and 20 seconds or more, and more preferably 500 seconds or less and 40 seconds or more.
[0185]
In the present invention, the matting agent is preferably contained in the outermost surface layer of the photosensitive material, the layer functioning as the outermost surface layer, or a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. It is preferable.
[0186]
5) Polymer latex
A polymer latex can be added to the surface protective layer or the back layer of the present invention.
For such polymer latex, “Synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing (1978))”, “Application of synthetic latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, Takashi "Molecular Publications (1993))" and "Synthetic Latex Chemistry (Muroichi Muroi, published by High Polymers Publication (1970))", specifically, methyl methacrylate (33.5% by mass) / Ethyl acrylate (50 wt%) / methacrylic acid (16.5 wt%) copolymer latex, methyl methacrylate (47.5 wt%) / butadiene (47.5 wt%) / itaconic acid (5 wt%) copolymer Latex, latex of ethyl acrylate / methacrylic acid copolymer, methyl methacrylate (58.9% by mass) / 2-ethyl A latex of xyl acrylate (25.4% by weight) / styrene (8.6% by weight) / 2-hydroxyethyl methacrylate (5.1% by weight) / acrylic acid (2.0% by weight) copolymer, methyl methacrylate (64. 0 mass%) / styrene (9.0 mass%) / butyl acrylate (20.0 mass%) / 2-hydroxyethyl methacrylate (5.0 mass%) / acrylic acid (2.0 mass%) copolymer latex, etc. Is mentioned.
[0187]
The polymer latex is preferably used in an amount of 10% by mass to 90% by mass, particularly preferably 20% by mass to 80% by mass, based on the total binder (including the water-soluble polymer and latex polymer) of the surface protective layer or the back layer.
[0188]
6) Membrane pH
The photothermographic material of the present invention preferably has a film surface pH of 7.0 or less, more preferably 6.6 or less before heat development. The lower limit is not particularly limited, but is about 3. The most preferred pH range is in the range of 4 to 6.2.
[0189]
The film surface pH is preferably adjusted using an organic acid such as a phthalic acid derivative, a non-volatile acid such as sulfuric acid, or a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is volatile and is preferable for achieving a low film surface pH because it can be removed before the coating process or heat development.
In addition, it is also preferable to use ammonia in combination with a nonvolatile base such as sodium hydroxide, potassium hydroxide, or lithium hydroxide. The method for measuring the film surface pH is described in paragraph No. 0123 of Japanese Patent Application No. 11-87297.
[0190]
7) Hardener
A hardener may be used for each layer such as the photosensitive layer, protective layer, and back layer of the present invention.
Examples of hardeners include T.W. H. There are various methods described in "The THEY OF OF THE PHOTOGRAPHIC PROCESS FOURTH EDITION" by James (published by Macmillan Publishing Co., Inc., published in 1977), pages 77 to 87. -S-triazine sodium salt, N, N-ethylenebis (vinylsulfonacetamide), N, N-propylenebis (vinylsulfonacetamide), polyvalent metal ions described on page 78 thereof, U.S. Pat. No. 4,281, Polyisocyanates such as 060 and JP-A-6-208193, epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A 62-89048 are preferred. Used.
[0191]
The hardening agent is added as a solution, and the addition time of this solution into the protective layer coating solution is from 180 minutes before to immediately before application, preferably from 60 minutes to 10 seconds before application. As long as the effects of the present invention are sufficiently exhibited, there is no particular limitation.
[0192]
Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's Koji Takahashi "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).
[0193]
8) Surfactant
Surfactants applicable to the present invention are described in paragraph No. 0132 of JP-A No. 11-65021.
In the present invention, it is preferable to use a fluorochemical surfactant. Preferable specific examples of the fluorosurfactant include compounds described in JP-A Nos. 10-197985, 2000-19680, 2000-214554 and the like. Further, a polymeric fluorine-based surfactant described in JP-A-9-281636 is also preferably used. In the present invention, the use of a fluorosurfactant described in Japanese Patent Application No. 2000-206560 is particularly preferred.
[0194]
9) Antistatic agent
In the present invention, an antistatic layer containing various known metal oxides or conductive polymers may be provided. The antistatic layer may also serve as the above-described undercoat layer, back layer surface protective layer, or the like, or may be provided separately. Regarding the antistatic layer, paragraph No. 0135 of JP-A No. 11-65021, paragraphs of JP-A Nos. 56-143430, 56-143431, 58-62646, No. 56-120519, and paragraphs of JP-A No. 11-84573. The techniques described in Paragraph Nos. 0078 to 0084 of Nos. 0040 to 0051, US Pat. No. 5,575,957 and JP-A-11-223898 can be applied.
[0195]
10) Support
The transparent support is a polyester, particularly polyethylene, which has been heat-treated in a temperature range of 130 to 185 ° C. in order to relieve internal strain remaining in the film during biaxial stretching and to eliminate thermal shrinkage strain generated during heat development. Terephthalate is preferably used.
[0196]
In the case of a photothermographic material for medical use, the transparent support may be colored with a blue dye (for example, dye-1 described in Examples of JP-A-8-240877) or may be uncolored.
Specific examples of the support are described in paragraph No. 0134 of JP-A No. 11-65021.
[0197]
Examples of the support include water-soluble polyesters disclosed in JP-A-11-84574, styrene-butadiene copolymers described in JP-A-10-186565, and vinylidene chloride described in JP-A-2000-39684 and Japanese Patent Application No. 11-106881, paragraph numbers 0063 to 0080. It is preferable to apply an undercoating technique such as a copolymer.
[0198]
11) Other additives
An antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, or a coating aid may be further added to the photothermographic material. A solvent described in paragraph No. 0133 of JP-A No. 11-65021 may be added. Various additives are added to either the photosensitive layer or the non-photosensitive layer. With respect to these, WO 98/36322, EP 803764A1, JP-A-10-186567, 10-18568 and the like can be referred to.
[0199]
12) Application method
The photothermographic material in the invention may be applied by any method. Specifically, various coating operations including extrusion coating, slide coating, curtain coating, dip coating, knife coating, flow coating, or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. Is used, and Stephen F. Kistler, Peter M. Extrusion coating or slide coating described in pages 399 to 536 of “LIQUID FILM COATING” (CHAPMAN & HALL, 1997) by Schweizer is preferably used, and slide coating is particularly preferably used.
[0200]
An example of the shape of a slide coater used for slide coating is shown in FIG. 11b. 1 If desired, two or more layers can be simultaneously coated by the method described on pages 399 to 536 of the same book, the method described in US Pat. No. 2,761,791 and British Patent No. 837,095. .
[0201]
The organic silver salt-containing layer coating solution in the present invention is preferably a so-called thixotropic fluid. Regarding this technique, JP-A-11-52509 can be referred to.
In the present invention, the organic silver salt-containing layer coating solution has a shear rate of 0.1 S.^-1The viscosity is preferably 400 mPa · s or more and 100,000 mPa · s or less, and more preferably 500 mPa · s or more and 20,000 mPa · s or less.
Also, shear rate 1000S^-1Is preferably 1 mPa · s or more and 200 mPa · s or less, more preferably 5 mPa · s or more and 80 mPa · s or less.
[0202]
The photothermographic material of the present invention is preferably heat-treated immediately after coating and drying. In particular, in the case of a photothermographic material using an aqueous latex as a binder, the film strength of the coating film is improved by this heat treatment, and it is preferable because it allows for various handling of the photothermographic material thereafter. The temperature of the heat treatment is the effective film surface temperature of the coating film and is preferably in the range of 60 ° C. to 100 ° C., and the heating time is preferably in the range of 1 second to 60 seconds. A more preferable range is a range of 70 ° C. to 90 ° C. and 2 seconds to 10 seconds. A preferable heat treatment method of the present invention is described in JP-A No. 2002-107872.
[0203]
13) Packaging materials
The photothermographic material of the present invention has an oxygen transmission rate and a photosensitivity in order to prevent deterioration of photographic performance during storage before use, or to prevent curling or wrinkling in the case of a rolled product form. It is preferable to hermetically package with a packaging material having a low moisture permeability. Oxygen permeability is 50 ml / atm / m at 25 ° C²-Day or less is preferable, more preferably 10 ml / atm / m²-Day or less, more preferably 1.0 ml / atm / m²-Day or less. Moisture permeability is 10 g / atm / m²-Day or less is preferable, more preferably 5 g / atm / m²-Day or less, more preferably 1 g / atm / m²-Day or less. As specific examples of the packaging material having low oxygen permeability and / or moisture permeability, those described in, for example, JP-A-8-254793 and JP-A-2000-206653 can be used.
[0204]
14) Other available technologies
Techniques that can be used for the photothermographic material of the present invention include EP80364A1, EP883022A1, WO98 / 36322, JP56-62648, 58-62644, JP9-43766, and 9-. 281637, 9-297367, 9-304869, 9-311405, 9-329865, 10-10669, 10-62899, 10-69023, 10-186568, 10-90823, 10-171106, 10-186565, 10-186567, 10-186567 to 10-186572, 10-197974, 10-197982, 10 -197983, 10-197985 to 10-197987, 10- 07001, 10-207004, 10-221807, 10-282601, 10-288823, 10-288824, 10-307365, 10-312038, 10-339934 11-7100, 11-15105, 11-24200, 11-24201, 11-30201, 11-30832, 11-84574, 11-65021, 11-109547, 11-125880, 11-129629, 11-133536 to 11-133539, 11-133542, 11-133543, 11-223898, 11-352627, 11- 305377, 11-305378, 11-305384, 11-30538 11-316435, 11-327076, 11-338096, 11-338098, 11-338099, 11-343420, Japanese Patent Application 2000-187298, 2000-10229 2000-47345, 2000-206642, 2000-98530, 2000-98531, 2000-112059, 2000-112060, 2000-112104, 2000-112604, No. 2000-171936 is also mentioned.
[0205]
15) Color image formation
The construction of a multicolor color photothermographic material may include a combination of these two layers for each color and contains all the components in a single layer as described in US Pat. No. 4,708,928. May be included.
In the case of a multicolor color photothermographic material, each emulsion layer is generally a functional or non-functional barrier layer between each photosensitive layer as described in U.S. Pat. No. 4,460,681. Are used to keep them distinguished from each other.
[0206]
2. Image forming method
2-1. exposure
The light-sensitive material of the present invention may be exposed by any method, but laser light is preferred as the exposure light source. A silver halide emulsion having a high silver iodide content as in the present invention has been problematic because of its low sensitivity. However, it has been found that writing with high illuminance such as laser light eliminates the problem of low sensitivity and allows image recording with less energy. The target sensitivity can be achieved by writing with such strong light in a short time.
[0207]
In particular, when an exposure amount giving the maximum density (Dmax) is given, the preferable light amount on the surface of the photosensitive material is 0.1 W / mm.²~ 100W / mm²It is. More preferably 0.5 W / mm²~ 50W / mm²And most preferably 1 W / mm²~ 50W / mm²It is.
[0208]
As the laser light according to the present invention, a gas laser (Ar⁺, He—Ne, He—Cd), YAG laser, dye laser, semiconductor laser and the like are preferable. A semiconductor laser and a second harmonic generation element can also be used. The laser preferably used is determined according to the light absorption peak wavelength of the photosensitizing material such as a spectral sensitizing dye, but it is a red to infrared emitting He-Ne laser, a red semiconductor laser, or a blue to green emitting Ar.⁺, He—Ne, He—Cd laser, blue semiconductor laser. In recent years, in particular, modules and blue semiconductor lasers, in which SHG (Second Harmonic Generator) elements and semiconductor lasers are integrated, have been developed, and laser output devices in the short wavelength region have been highlighted. The blue semiconductor laser is expected to increase in demand in the future because high-definition image recording is possible, the recording density is increased, and a stable output is obtained with a long lifetime. The peak wavelength of the laser light is 300 nm to 500 nm of blue, preferably 400 nm to 500 nm, and 600 nm to 900 nm of red to near infrared, preferably 620 nm to 850 nm.
[0209]
It is also preferable that the laser light is oscillated in a vertical multi by a method such as high frequency superposition.
[0210]
2-2. Heat development
The photothermographic material of the present invention may be developed by any method, but is usually developed by raising the temperature of the photothermographic material exposed imagewise. The preferred development temperature is 80 to 250 ° C, more preferably 100 to 140 ° C.
The development time is preferably 1 to 60 seconds, more preferably 5 to 30 seconds, and particularly preferably 5 to 20 seconds.
[0211]
A plate heater method is preferred as the heat development method. The heat development method using the plate heater method is preferably a method described in JP-A-11-133572. The heat development photosensitive material on which a latent image is formed is brought into contact with a heating means in a heat development part, and heat for obtaining a visible image. In the developing device, the heating unit includes a plate heater, and a plurality of press rollers are disposed to face each other along one surface of the plate heater, and the heat is interposed between the press roller and the plate heater. A thermal development apparatus that performs thermal development by passing a development photosensitive material. It is preferable to divide the plate heater into 2 to 6 stages and lower the temperature about 1 to 10 ° C. at the tip.
[0212]
Such a method is also described in JP-A-54-30032, which can exclude moisture and organic solvents contained in the photothermographic material out of the system, and rapidly develop the photothermographic material. It is also possible to suppress changes in the shape of the support of the photothermographic material due to heating of the photothermographic material.
[0213]
2-3. system
As a medical laser imager provided with an exposure part and a heat development part, Fuji Medical Dry Imager-FM-DPL can be mentioned. The system is Fuji Medical Review No. 8, pages 39 to 55, and these techniques can be used. Further, it can also be applied as a photothermographic material for a laser imager in “AD network” proposed by Fuji Medical as a network system conforming to the DICOM standard.
[0214]
3. Application of the present invention
The photothermographic material using the high silver iodide photographic emulsion of the present invention forms a black-and-white image with a silver image, and is a photothermographic material for medical diagnosis, a photothermographic material for industrial photography, and a photothermographic material for printing. It is preferably used as a photothermographic material for COM.
[0215]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
[0216]
Example 1.
1. Preparation of PET support and undercoating
1-1. Film formation
[0217]
Using terephthalic acid and ethylene glycol, PET having an intrinsic viscosity of IV = 0.66 (measured at 25 ° C. in phenol / tetrachloroethane = 6/4 (weight ratio)) was obtained according to a conventional method. This was pelletized and dried at 130 ° C. for 4 hours. Thereafter, the film was extruded from a T-die and quenched to prepare an unstretched film having a thickness such that the film thickness after heat setting was 175 μm.
[0218]
This was longitudinally stretched 3.3 times using rolls with different peripheral speeds, and then stretched 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. Thereafter, the film was heat-fixed at 240 ° C. for 20 seconds and relaxed by 4% in the lateral direction at the same temperature. After slitting the chuck part of the tenter, knurling is performed on both ends and 4 kg / cm.²And a roll having a thickness of 175 μm was obtained.
[0219]
1-2. Surface corona treatment
Using a solid state corona treatment machine 6KVA model manufactured by Pillar, both surfaces of the support were treated at room temperature at 20 m / min. From the current and voltage readings at this time, the support is 0.375 kV · A · min / m.²It was found that the process was done. The treatment frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.
[0220]
1-3. undercoat
1) Preparation of undercoat layer coating solution
Formulation (1) (for the undercoat layer on the photosensitive layer side)
Pesresin A-520 (30% by mass solution) manufactured by Takamatsu Yushi Co., Ltd. 59 g
Polyethylene glycol monononyl phenyl ether 5.4 g
(Average ethylene oxide number = 8.5) 10% by mass solution
MP-1000 (polymer fine particles, average particle size 0.4 μm) 0.91 g manufactured by Soken Chemical Co., Ltd.
Distilled water 935 ml distilled water
[0221]
Formulation (2) (for back layer 1st layer)
Styrene-butadiene copolymer latex 158 g
(Solid content 40% by mass, styrene / butadiene weight ratio = 68/32)
2,4-Dichloro-6-hydroxy-S-triazine sodium salt
(8% by weight aqueous solution) 20g 20g
1% by weight aqueous solution of sodium laurylbenzenesulfonate 10 ml
Distilled water 854 ml of distilled water
[0222]
Formula (3) (Back side 2nd layer)
SnO₂/ SbO (9/1 mass ratio, average particle size 0.038 μm, 17 mass% dispersion) 84 g
Gelatin (10% by mass aqueous solution) 89.2 g of the gas
Metroise TC-5 (2 mass% aqueous solution) manufactured by Shin-Etsu Chemical Co., Ltd. 8.6 g
MP-1000, Soken Chemical Co., Ltd., 0.01g, 0.01g
10 ml of 1% by weight aqueous solution of sodium dodecylbenzenesulfonate 10 ml
NaOH (1% by mass), 10% of the water, and 6ml of the water.
Proxel (made by ICI) 1 ml
Distilled water 805ml
[0223]
2) Undercoat
After both surfaces of the biaxially stretched polyethylene terephthalate support having a thickness of 175 μm are subjected to the corona discharge treatment, the undercoat coating solution formulation {circle around (1)} is applied to one surface (photosensitive layer surface) with a wire bar. .6ml / m²(Per side) and dried at 180 ° C. for 5 minutes, and then the undercoat coating liquid formulation (2) is applied to the back side (back side) with a wire bar at a wet coating amount of 5.7 ml / m.²And then dried at 180 ° C. for 5 minutes. Further, the undercoat coating liquid formulation (3) is applied to the back surface (back surface) with a wire bar so that the wet coating amount is 7.7 ml / m.²And then dried at 180 ° C. for 6 minutes to prepare an undercoat support.
[0224]
2. Back layer
2-1. Preparation of back layer coating solution
1) Preparation of solid precursor dispersion (a) of base precursor
64 g of base precursor compound-1, 10 g of Demol N (trade name, Kao Corporation), 28 g of diphenylsulfone and 220 ml of distilled water were added and mixed. ) To obtain a solid fine particle dispersion (a) of a base precursor compound having an average particle size of 0.2 μm.
[0225]
2) Preparation of dye solid fine particle dispersion (a)
9.6 g of cyanine dye compound-1, 5.8 g of sodium p-dodecyl sulfonate, and 305 ml of distilled water were mixed, and the mixture was dispersed in beads with a 1/4 G sand grinder mill (manufactured by IMEX Co., Ltd.). An occupied solid fine particle dispersion (a) having an average particle size of 0.2 μm was obtained.
[0226]
3) Preparation of antihalation layer coating solution
Gelatin 17 g, polyacrylamide 9.6 g, solid fine particle dispersion (a) 70 g of the above base precursor, 56 g of the above dye solid fine particle dispersion (a), monodisperse polymethyl methacrylate fine particles (average particle size 8 μm, particle size) Standard deviation 0.4) 1.5 g, benzoisothiazolinone 0.03 g, sodium polyethylene sulfonate 2.2 g, blue dye compound-1 0.2 g, yellow dye compound-1 3.9 g, and water 844 ml. By mixing, an antihalation layer coating solution was prepared.
[0227]
4) Preparation of back surface protective layer coating solution
The container was kept at 40 ° C., 50 g of gelatin, 0.2 g of sodium polystyrenesulfonate, 2.4 g of N, N-ethylenebis (vinylsulfoneacetamide), 1 g of sodium t-octylphenoxyethoxyethanesulfonate, 30 mg of benzoisothiazolinone , 37 mg of fluorosurfactant (F-1), 0.15 g of fluorosurfactant (F-2), 64 mg of fluorosurfactant (F-3), 32 mg of fluorosurfactant (F-4) 8.8 g of acrylic acid / ethyl acrylate copolymer (copolymerization weight ratio 5/95), 0.6 g of aerosol OT (American Cyanamid Co., Ltd.), 1.8 g of liquid paraffin emulsion as liquid paraffin, water Was mixed to prepare a coating solution for the back surface protective layer.
[0228]
2-2. Back layer application
On the back surface side of the undercoat support, an antihalation layer coating solution is applied at a solid fine particle dye coating amount of 0.04 g / m.²In addition, the back surface protective layer coating solution has a gelatin coating amount of 1.7 g / m.²A multi-layer coating was applied and dried to form a back layer.
[0229]
3. Image forming layer, intermediate layer, and surface protective layer
3-1. Preparation of coating materials
1) Silver halide emulsion
[0230]
(Preparation of comparative silver halide emulsion A)
To a solution of 1420 ml of distilled water, 4.3 ml of a 1% by weight potassium iodide solution, 3.5 ml of 0.5 mol / L sulfuric acid, and 36.7 g of phthalated gelatin were added and stirred in a stainless steel reaction vessel. While maintaining the liquid temperature at 35 ° C., a solution A in which 22.22 g of silver nitrate was diluted with distilled water to 195.6 ml and a solution B in which 21.8 g of potassium iodide was diluted with distilled water to a volume of 219 ml were added at a constant flow rate. The whole amount was added over a period of minutes. Thereafter, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added, and 10.8 ml of a 10% by mass aqueous solution of benzimidazole was further added. Further, Solution C obtained by adding distilled water to 51.86 g of silver nitrate and diluting to 317.5 ml and Solution D obtained by diluting 60 g of potassium iodide to a volume of 600 ml with distilled water were added to Solution C over 120 minutes at a constant flow rate. Solution D was added by the controlled double jet method while maintaining pAg at 8.1.
[0231]
1 x 10 per mole of silver^-4The total amount of potassium iridium (III) hexachloride was added 10 minutes after the start of the addition of the solution C and the solution D so as to have a molarity. The pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 8.0. The grains in the prepared silver halide emulsion were pure silver iodide grains having an average sphere equivalent diameter of 0.037 μm and a sphere equivalent diameter variation coefficient of 17%. The particle size and the like were determined from an average of 1000 particles using an electron microscope.
[0232]
While maintaining the silver halide dispersion at 38 ° C. with stirring, 5 ml of a methanol solution of 0.34% by mass of 1,2-benzisothiazolin-3-one was added, and after 40 minutes, the sensitizing dye A and the sensitizing dye A were increased. A methanol solution of 1: 1 in the molar ratio of dye B is 1.2 × 10 as the sum of sensitizing dyes A and B per mole of silver.^-3Mole was added and the temperature was raised to 47 ° C. after 1 minute. 20 minutes after the temperature rise, sodium benzenethiosulfonate was 7.6 × 10 6 in 1 mol of silver with a methanol solution.^-5Mole was added, and after 5 minutes of preparation to pAg 5.5, tellurium sensitizer (bis (N-phenyl-N-methylcarbamoyl) telluride) was added to 5.1 × 10 5.^-4Mol / mol silver was added and aged for 84 minutes. After the pAg of the emulsion was adjusted to 7.5, 1.3 ml of a 0.8 mass% methanol solution of N, N′-dihydroxy-N ″ -diethylmelamine was added, and after further 4 minutes, 5-methyl-2-mercapto was added. Benzoimidazole in methanol solution at 4.8 x 10 per mole of silver^-3Mole and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole in a methanol solution at 5.4 × 10 5 per mole of silver^-3A comparative silver halide emulsion A was prepared by adding a molar amount.
[0233]
(Preparation of comparative silver halide emulsion B)
In the preparation of comparative silver halide emulsion A, an aqueous solution of potassium iron (II) hexacyanide instead of potassium hexachloroiridate (III) was used in an amount of 3 × 10 5 per mol of silver.^-3Comparative silver halide emulsion B was prepared in the same manner except that all the molar amount was added.
[0234]
(Preparation of comparative silver halide emulsion C)
A comparative silver halide emulsion C was prepared in the same manner as in the preparation of comparative silver halide emulsion A except that potassium hexachloroiridate (III) was omitted.
[0235]
(Preparation of silver halide emulsions -1 to 7 of the present invention)
Emulsion-1: Ir / Fe (Ir: uniform, Fe: uniform)
In the preparation of comparative silver halide emulsion A, 5 × 10 5 per mole of silver^-4Moles and 5 × 10^-3The silver halide emulsion 1 of the present invention was prepared in the same manner by adding solution C and solution D to each of potassium hexachloroiridate (III) and potassium iron (II) hexacyanide so that the molar tops were uniform. Prepared.
Emulsion-2: Ir / Fe (Ir: core, Fe: shell)
In the preparation of the silver halide emulsion 1 of the present invention, an aqueous solution of potassium hexachloroiridium (III) is added only to the solution C instead of the solution C and the solution D so as to be the core part dope so that the shell part is doped. A silver halide emulsion 2 of the present invention was prepared in the same manner except that an aqueous solution of potassium iron (II) hexacyanide was added only to the solution D instead of the solution C and the solution D.
Emulsion-3: Ir / Fe (Ir: core, Fe: surface)
In preparation of the silver halide emulsion 1 of the present invention, an aqueous solution of potassium iron (II) hexacyanide was added directly to the grain formation reaction vessel after the grain formation instead of the solution C and the solution D. Inventive silver halide emulsion 3 was prepared.
Emulsion-4: Ru / Fe (Ru: core, Fe: surface)
In the preparation of the silver halide emulsion 3 of the present invention, an aqueous potassium hexachlororuthenium (II) solution was used instead of the potassium hexachloroiridate (III) solution at 5 × 10 5 per mol of silver.^-4A silver halide emulsion 4 of the present invention was prepared in the same manner except that it was added in a molar amount.
Emulsion-5: Cu / Fe (Cu: core, Fe: surface)
In the preparation of the silver halide emulsion 3 of the present invention, an aqueous solution of copper (III) nitrate was used instead of the potassium hexachloroiridate (III) solution at 5 × 10 5 per mol of silver.^-4A silver halide emulsion 5 of the present invention was prepared in the same manner except that the amount was adjusted to be molar.
Emulsion-6: Fe / Pt (Fe: core, Pt: surface)
In the preparation of the silver halide emulsion 5 of the present invention, an aqueous solution of potassium iron (II) hexacyanide was used instead of the aqueous solution of copper (II) nitrate at 5 × 10 5 per mol of silver.^-3In addition to an aqueous solution of potassium iron (II) hexacyanide, an aqueous solution of potassium tetrachloroplatinate (II) is added in an amount of 5 × 10 5 per mol of silver.^-3A silver halide emulsion 6 of the present invention was prepared in the same manner except that it was added in a molar amount.
Emulsion-7: Os / Fe (Os: core, Fe: surface)
In the preparation of the silver halide emulsion 4 of the present invention, an aqueous solution of potassium hexachloroosmium (III) was used in place of the aqueous solution of potassium hexaiodolthenium (II) at 5 × 10 5 per mol of silver.^-4A silver halide emulsion 4 of the present invention was prepared in the same manner except that it was added in a molar amount.
[0236]
(Preparation of emulsions 1a to 1c and 1 to 7 for coating solution addition)
The above silver halide emulsions were dissolved in small portions, and 1- (3-methylureido) phenyl-5-mercaptotetrazole was added to each 5 × 10 5 mol of silver.^-3Thereafter, the mixture was added so that the content of silver halide per 1 kg of the coating solution addition emulsion was 38.2 g as silver.
[0237]
2) Preparation of fatty acid silver dispersion
Henkel behenic acid (product name Edenor C22-85R) 87.6 Kg, distilled water 423 L, 5 mol / L NaOH aqueous solution 49.2 L, tert-butanol 120 L were mixed and stirred at 75 ° C. for 1 hour to react. A sodium behenate solution was obtained. Separately, 206.2 L (pH 4.0) of an aqueous solution containing 40.4 kg of silver nitrate was prepared and kept warm at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of tert-butanol was kept at 30 ° C., and with sufficient stirring, the total amount of the previous sodium behenate solution and the total amount of silver nitrate aqueous solution were 93 minutes and 15 seconds at a constant flow rate, respectively. Added over 90 minutes. At this time, only the silver nitrate aqueous solution is added for 11 minutes after the start of the addition of the aqueous silver nitrate solution, and then the addition of the sodium behenate solution is started. After the addition of the aqueous silver nitrate solution, only the sodium behenate solution is added for 14 minutes and 15 seconds. It was made to be. At this time, the temperature in the reaction vessel was 30 ° C., and the external temperature was controlled so that the liquid temperature was constant. The pipe of the addition system for the sodium behenate solution was kept warm by circulating hot water outside the double pipe so that the liquid temperature at the outlet at the tip of the addition nozzle was 75 ° C. Moreover, the piping of the addition system of the silver nitrate aqueous solution was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically around the stirring axis, and were adjusted so as not to contact the reaction solution.
[0238]
After completion of the addition of the sodium behenate solution, the mixture was left stirring for 20 minutes at the same temperature, heated to 35 ° C. over 30 minutes, and then aged for 210 minutes. Immediately after completion of aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of filtered water reached 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.
[0239]
When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, the average values were a = 0.14 μm, b = 0.4 μm, c = 0.6 μm, average aspect ratio 5.2, average sphere equivalent diameter. It was a flake-like crystal having a variation coefficient of 15% for a sphere equivalent diameter of 0.52 μm. (A, b, and c are the text provisions)
[0240]
19.3 kg of polyvinyl alcohol (trade name: PVA-217, Kuraray Co., Ltd.) and water are added to the wet cake corresponding to a dry solid content of 260 kg. Pre-dispersed with a mixer (manufactured by Mizuho Kogyo Co., Ltd .: PM-10 type).
[0241]
Next, the pre-dispersed stock solution is subjected to a pressure of 1260 kg / cm of a disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using a Z-type interaction chamber).²And was treated three times to obtain a silver behenate dispersion. The cooling operation was carried out by installing a serpentine heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a dispersion temperature of 18 ° C.
[0242]
3) Preparation of reducing agent dispersion (a)
Add 7 kg of water to 10 kg of reducing agent complex-1 and 0.12 kg of triphenylphosphine oxide and 16 kg of 10 wt% aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) and mix well. A slurry was obtained. This slurry was fed with a diaphragm pump and dispersed for 4 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to prepare a reducing agent complex concentration of 25% by mass to obtain a reducing agent dispersion (a). The reducing agent complex particles contained in the dispersion thus obtained had a median diameter of 0.46 μm and a maximum particle diameter of 1.6 μm or less. The obtained reducing agent complex dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign matters such as dust and stored.
[0243]
4) Preparation of polyhalogen compound
(Preparation of organic polyhalogen compound dispersion (a))
Add 10 kg of organic polyhalogen compound-1 and 10 kg of 20 wt% aqueous solution of modified polyvinyl alcohol MP203, 0.4 kg of 20 wt% aqueous solution of sodium triisopropylnaphthalenesulfonate, and 14 kg of water, and mix well to form a slurry. did. This slurry was fed with a diaphragm pump and dispersed in a horizontal sand mill UVM-2 filled with zirconia beads having an average diameter of 0.5 mm for 5 hours. Then, 0.2 g of benzoisothiazolinone sodium salt and water were added to the organic poly An organic polyhalogen compound dispersion (a) was obtained by adjusting the concentration of the halogen compound to be 26% by mass. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust and stored.
[0244]
(Preparation of organic polyhalogen compound dispersion (b))
Add 10 kg of organic polyhalogen compound-2, 20 kg of a 10% by weight aqueous solution of modified polyvinyl alcohol MP203, 0.4 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate, and 8 kg of water, and mix well to form a slurry. did. This slurry was fed with a diaphragm pump and dispersed in a horizontal sand mill UVM-2 filled with zirconia beads having an average diameter of 0.5 mm for 5 hours. Then, 0.2 g of benzoisothiazolinone sodium salt and water were added to the organic poly The concentration of the halogen compound was adjusted to 25% by mass. This dispersion was heated at 40 ° C. for 5 hours to obtain an organic polyhalogen compound-3 dispersion. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.36 μm and a maximum particle diameter of 1.5 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.
[0245]
6) Preparation of phthalazine compound-1 solution
8 kg of modified polyvinyl alcohol MP203 is dissolved in 174.57 kg of water, and then 3.15 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate and 14.28 kg of a 70% by weight aqueous solution of phthalazine compound-1 (6-isopropylphthalazine). Was added to prepare a 5 mass% solution of phthalazine compound-1.
[0246]
7) Preparation of mercapto compound-1 aqueous solution
7 g of mercapto compound-1 was dissolved in 993 g of water to obtain a 0.7% by mass aqueous solution.
[0247]
8) Preparation of pigment-1 dispersion
C. I. Pigment Blue 60 (64 g) and Kao Corp. demole N (6.4 g) were added to 250 g of water and mixed well to prepare a slurry. Prepare 800 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, disperse with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) for 25 hours, take out from the vessel, To obtain a pigment-1 dispersion having a pigment concentration of 5 mass%. The pigment particles contained in the pigment dispersion thus obtained had an average particle size of 0.21 μm.
[0248]
9) Preparation of SBR latex solution
The SBR latex with Tg = 23 ° C. was prepared as follows.
Ammonium persulfate is used as a polymerization initiator, an anionic surfactant is used as an emulsifier, 70.5 parts by mass of styrene, 26.5 parts by mass of butadiene and 3 parts by mass of acrylic acid are subjected to emulsion polymerization, and then aging is performed at 80 ° C. for 8 hours. went. Thereafter, the mixture was cooled to 40 ° C., adjusted to pH 7.0 with aqueous ammonia, and Sandet BL manufactured by Sanyo Chemical Co., Ltd. was further added to 0.22%. Next, 5% aqueous sodium hydroxide solution was added to adjust the pH to 8.3, and further adjusted to pH 8.4 with aqueous ammonia. Na used at this time⁺Ion and NH₄ ⁺The molar ratio of ions was 1: 2.3. Further, 0.15 ml of a 7% aqueous solution of benzoisothiazoline non sodium salt was added to 1 kg of this liquid to prepare an SBR latex liquid.
[0249]
(SBR latex: Latex of -St (70.5) -Bu (26.5) -AA (3)-)
Tg = 23 ° C. Average particle size 0.1 μm, concentration 43% by mass, equilibrium water content 0.6% by mass at 25 ° C. 60% RH, ion conductivity 4.2 mS / cm (Ion conductivity is measured by Toa Denpa Kogyo ( Co., Ltd. conductivity meter CM-30S was used, and the latex stock solution (43% by mass) was measured at 25 ° C.), pH 8.4.
SBR latexes having different Tg were adjusted in the same manner by appropriately changing the ratio of styrene and butadiene.
[0250]
3-2. Preparation of coating solution
1) Preparation of coating solution for image forming layer
1000 g of fatty acid silver dispersion obtained above, 104 ml of water, 30 g of pigment-1 dispersion, 6.3 g of organic polyhalogenated compound dispersion (a), 20.7 g of organic polyhalogen compound dispersion (b), phthalazine compound-1 173 g of solution, 1082 g of SBR latex (Tg: 23 ° C.), 258 g of reducing agent dispersion (a), and 9 g of mercapto compound-1 solution were sequentially added. Is added so that the amount of the organic acid silver is 6.6% in terms of the molar ratio of silver, and the well-mixed image forming layer coating solutions 1a to 1c and 1 to 7 are prepared, and are directly fed to the coating die. Applied.
[0251]
2) Preparation of intermediate layer coating solution
772 g of 10 mass% aqueous solution of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 5.3 g of pigment-1 dispersion, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer mass ratio) 64/9/20/5/2) 226 g of 27.5 wt% latex, 2 ml of 5 wt% aqueous solution of aerosol OT, 10.5 ml of 20 wt% aqueous solution of diammonium phthalate, total amount 880 g Water was added to the solution and adjusted with NaOH so that the pH was 7.5 to obtain an intermediate layer coating solution of 10 ml / m²Then, the solution was fed to the coating die.
The viscosity of the coating solution was 65 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).
[0252]
3) Preparation of surface protective layer first layer coating solution
Inert gelatin (64 g) is dissolved in water, and methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization mass ratio 64/9/20/5/2) 27.5% by weight latex 80 g, 23 ml of 10% by weight methanol solution of phthalic acid, 23 ml of 10% by weight aqueous solution of 4-methylphthalic acid, 28 ml of sulfuric acid having a concentration of 0.5 mol / L, 5 ml of 5% by weight aqueous solution of aerosol OT, 0.5 g of phenoxyethanol, 0.1 g of isothiazolinone was added, water was added so that the total amount was 750 g, and 26 ml of 4% by weight chromium alum was mixed with a static mixer immediately before coating to 18.6 ml / m.²Then, the solution was fed to the coating die.
The viscosity of the coating solution was 20 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).
[0253]
4) Preparation of surface protective layer second layer coating solution
80 g of inert gelatin is dissolved in water, and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization mass ratio 64/9/20/5/2) latex 27.5% by mass solution 102 g, 3.2 ml of a 5% by weight solution of a fluorosurfactant (F-1), 32 ml of a 2% by weight aqueous solution of the fluorosurfactant (F-2), 23 ml of a 5% by weight solution of aerosol OT, poly 4 g of methyl methacrylate fine particles (average particle size 0.7 μm), 21 g of polymethyl methacrylate fine particles (average particle size 4.5 μm), 1.6 g of 4-methylphthalic acid, 4.8 g of phthalic acid, 44 ml of 0.5 mol / L sulfuric acid Water was added to 10 mg of benzoisothiazolinone so that the total amount was 650 g, and 4% by mass of chromium alum and 0.6% were added. A solution prepared by mixing 445 ml of an aqueous solution containing 7% by mass of phthalic acid with a static mixer immediately before coating is used as the surface protective layer second layer coating solution, and 8.3 ml / m.²Then, the solution was fed to the coating die.
The viscosity of the coating solution was 19 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).
[0254]
3-3. Preparation of photothermographic materials 1a to 1c and 1 to 7
[0255]
A photothermographic material sample was coated on the surface opposite to the back surface in the order of an image forming layer, an intermediate layer, a surface protective layer first layer, and a surface protective layer second layer in this order by a slide bead coating method. It was created. At this time, the coating solution for the image forming layer and the intermediate layer was adjusted to 35 ° C., the first surface protective layer was adjusted to 36 ° C., and the second surface protective layer was adjusted to 37 ° C.
Coating amount of each compound in the image forming layer (g / m²) Is as follows.
[0256]
Silver behenate 6.19
Pigment (CI Pigment Blue 60) 0.036
Polyhalogen compound-1 0.04
Polyhalogen compound-2 0.12
Phthalazine Compound-1 0.21
SBR Latex 11.1
Reducing agent complex-1 1.54 1.54
Mercapto compound-1 0.002
Silver halide (as Ag) 0.10
Type 1-4 compounds (shown in Table 1)
1 x 10 per mole of silver halide^-3Mole
[0257]
The coating and drying conditions are as follows.
The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating.
In the subsequent chilling zone, after cooling the coating solution with wind at a dry bulb temperature of 10 to 20 ° C., the coating solution is transported in a non-contact manner, and dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC. Thus, coated samples 21 to 27 were obtained.
After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.
[0258]
The photothermographic material thus prepared had a Beck smoothness of 550 seconds on the image forming layer surface side and 130 seconds on the back surface. Further, the pH of the film surface on the image forming layer surface side was measured and found to be 6.0.
[0259]
The chemical structures of the compounds used in the examples of the present invention are shown below.
[0260]
Embedded image

[0261]
Embedded image

[0262]
Embedded image

[0263]
Embedded image

[0264]
Embedded image

[0265]
4). Evaluation of photographic performance
(Preparation)
The obtained sample was cut into half-cut sizes, packaged in the following packaging materials in an environment of 25 ° C. and 50%, and stored at room temperature for 2 weeks.
(Packaging material)
PET 10 μm / PE 12 μm / Aluminum foil 9 μm / Ny 15 μm / Polyethylene 50% containing carbon 3%, Oxygen permeability: 0.02 ml / atm · m²・ 25 ° C./day, moisture permeability: 0.10 g / atm · m²-25 degreeCday.
[0266]
The above photothermographic material was evaluated as follows.
(Exposure of photosensitive material)
The light-sensitive material was exposed as follows.
Fuji Medical Dry Laser Imager FM-DPL was modified and exposed and developed. The exposure was performed by irradiating the light-sensitive material with a 660 nm semiconductor laser having a maximum output of 60 mW (IIIB) mounted on FM-DPL, narrowed to 100 μm × 100 μm. The exposure was performed by changing the exposure amount of the laser stepwise. Development was a total of 24 seconds with four panel heaters set at 112 ° C.-119 ° C.-121 ° C.-121 ° C. using the FM-DPL thermal development section.
[0267]
(Evaluation of Sample) The obtained image was subjected to density measurement with a Macbeth densitometer, and a density characteristic curve with respect to the logarithm of the exposure amount was created.
Sensitivity: Sensitivity is expressed by the reciprocal of the exposure amount giving a blackening density of fog + 1.0. The sensitivity of 1 is taken as 100, and the relative value is shown. A larger value indicates higher sensitivity.
Dmin: The density of the non-image area was measured with a Macbeth densitometer.
Image storability: The heat-developed sample was cut into half-cut sizes, stored in a fluorescent lamp with an illuminance of 1000 Lux under an environment of 30 ° C. and 70% RH, and then evaluated for an increase in fog density in the Dmin part.
[0268]
The results obtained are shown in Table 1. As can be seen from the results, the photothermographic material of the present invention has high sensitivity obtained by two or more kinds of metal dopes, and maintains a low Dmin level, and the printout performance after heat development is also iodinated. The good level characteristic of using silver emulsion was maintained.
[0269]
[Table 1]

[0270]
Example 2
A silver iodide emulsion was prepared in the same manner as in the silver halide emulsion of Example 1, but without addition of sensitizing dyes A and B. Other than that, the coated samples 2a, 2b, 21 to 27 were prepared in the same manner as in Example 1. Got. Thereafter, treatment was performed in the same manner as in Example 1 except that 405 nm blue laser light was used, and the results shown in Table 2 were obtained. The relative sensitivity was expressed as a relative ratio with Sample 21 as 100.
[0271]
[Table 2]

[0272]
As is apparent from Table 2, the photothermographic material of the present invention has high sensitivity obtained by two or more kinds of metal dopes, maintains a low Dmin, and has a printout performance after heat development. The good level characteristic of the silver halide emulsion was maintained.
[0273]
Example 3
In Example 1, emulsions were prepared by changing the type of doped metal of the photosensitive silver halide emulsion as shown in Table 3. The first metal is 5 x 10 per mole of silver^-4Mole is added and the second metal is 3 x 10 per mole of silver.^-3Mole was added.
[0274]
The results evaluated in the same manner as in Example 1 are shown in Table 3. Sensitivity was expressed as relative sensitivity when the first metal alone was used as 100, and was shown so that the combined effect of two metal dopes could be clearly understood. As in Example 1, the photothermographic material of the present invention has high sensitivity obtained by two kinds of metal dope, maintains a low Dmin, and has a printout performance after heat development of silver iodide. The good level characteristic of the emulsion was maintained.
[0275]
[Table 3]

[0276]
【The invention's effect】
According to the present invention, a photothermographic material excellent in printout performance of an image after heat development processing and having high sensitivity and low Dmin can be obtained.

Claims (11)

In a photothermographic material containing at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions, and a binder on one side of the support, the photosensitive silver halide is 1 2) The silver iodide content is 10 mol% or more and 100 mol% or less, 2) at least one metal selected from the following first metal group and at least one metal selected from the following second metal group A photothermographic material comprising two or more metals.
(First metal group)
Iridium, ruthenium, iron, osmium, copper (second metal group)
Iridium, ruthenium, iron, osmium, rhenium, gold, platinum, copper, indium, gallium, lead, thallium, chromium, palladium, nickel, zinc However, selected from the metal selected from the first metal group and the second metal group The metals are not the same. 2. The photothermographic material according to claim 1, wherein the photosensitive silver halide contains a metal having the following combination of the first metal and the second metal.
(Ir-Fe), (Ir-Cu), (Ru-Cu), (Ru-Fe), (Fe-Os), (Fe-Ru), (Fe-Cu), (Fe-Pt), (Os -Cu), (Os-Fe), (Cu-Fe), (Cu-Ru) The photosensitive silver halide is composed of a first metal and a second metal (Ir-Fe), (Ru-Fe), (Fe-Cu), (Fe-Pt), (Ru-Cu), (Os- 2. The photothermographic material according to claim 1, comprising a metal in a combination of (Fe), (Cu—Fe), and (Cu—Ru). 2. The photothermographic material according to claim 1, wherein the first metal is distributed in the core and the second metal is distributed in the shell. 5. The photothermographic material according to claim 1, wherein the silver halide emulsion is chemically sensitized by at least one of chalcogen sensitization, gold sensitization and reduction sensitization. 6. The photothermographic material according to claim 5, wherein the chalcogen sensitization is tellurium sensitization, selenium sensitization, or sulfur sensitization. 7. The photothermographic material according to claim 5, wherein the chalcogen sensitization is tellurium sensitization or selenium sensitization. 8. The photothermographic material according to claim 5, wherein the chalcogen sensitization is tellurium sensitization. 9. The photothermographic material according to claim 1, wherein the silver halide photographic emulsion has a silver iodide content of 40 mol% or more and 100 mol% or less. The photothermographic material according to claim 9, wherein the silver halide content of the silver halide photographic emulsion is 90 mol% or more and 100 mol% or less. 11. The photothermographic material according to claim 1, wherein the silver halide grains have a grain size of 50 nm or less and 10 nm or more.