JP2004352818A - Antistatic composite copolymer aqueous dispersion, plastic film having antistatic layer using it and material for silver salt photothermographic dry imaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion of an organic solvent- and organic amine-free antistatic agent having a reduced load on the environment, an antistatic-coated film having excellent antistaticity and not causing the break of the percolation transition even at elevated temperatures and a material for silver salt photothermographic dry imaging with a controlled rate of fogging even after long term storage. <P>SOLUTION: The composite copolymer aqueous dispersion is obtained by dispersion-polymerizing a vinylic monomer in an aqueous dispersion mixed with a tin oxide-based compound and a water-dispersible copolyester. The plastic film having an antistatic layer is also presented on which the composite copolymer aqueous dispersion is coated directly or via another layer. The material for silver salt photothermographic dry imaging is also presented in which the composite copolymer aqueous dispersion is coated on the plastic film directly or via another layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１１１】
一般式（Ａ）中、Ｘが表すカルコゲン原子としては、硫黄、セレン、テルルであり、好ましくは硫黄原子である。
【０１１２】
Ｒは水素原子、ハロゲン原子、炭素数が７以下の脂肪族基又は６員環以下の環状基を表し、ハロゲン原子としては、例えば弗素、塩素、臭素原子等である。炭素数が７以下の脂肪族基としては、例えばメチル、エチル、プロピル、ブチル、ヘキシル、ヘプチル、ビニル、アリル、ブテニル、ヘキサジエニル、エテニル−２−プロペニル、３−ブテニル、１−メチル−３−プロペニル、３−ペンテニル、１−メチル−３−ブテニル基等である。６員環以下の環状基としては、脂環式基、複素環基を含み、炭素環式基としては、シクロブテン、シクロペンチル、シクロペンテニル、シクロヘキシル、シクロへキセニル、シクロヘキサジエニル、フェニル基等の４〜６員環が好ましく、複素環基としては、ピラゾリル、ピロリル、ピロリジニル、ピリミジニル、ピラジル、ピリジル、トリアジニル、チアゾリル、フリル、ピラニル等の５、６員環基が好ましく、特に好ましくは水素原子又はシクロアルキル基、シクロアルケニル基、フェニル基等の環状構造を有する基である。
【０１１３】
これらの基は更に置換基を有してもよく、該置換基としては、ハロゲン原子（弗素、塩素、臭素等）、シクロアルキル基（シクロヘキシル、シクロヘプチル等）、シクロアルケニル基（１−シクロアルケニル基、２−シクロアルケニル基等）、アルコキシ基（メトキシ、エトキシ、プロポキシ等）、アルキルカルボニルオキシ基（アセチルオキシ等）、アルキルチオ基（メチルチオ、トリフルオロメチルチオ等）、カルボキシル基、アルキルカルボニルアミノ基（アセチルアミノ等）、ウレイド基（メチルアミノカルボニルアミノ等）、アルキルスルホニルアミノ基（メタンスルホニルアミノ等）、アルキルスルホニル基（メタンスルホニル、トリフルオロメタンスルホニル等）、カルバモイル基（カルバモイル、Ｎ，Ｎ−ジメチルカルバモイル、Ｎ−モルホリノカルボニル等）、スルファモイル基（スルファモイル、Ｎ，Ｎ−ジメチルスルファモイル、モルホリノスルファモイル等）、トリフルオロメチル基、ヒドロキシル基、ニトロ基、シアノ基、アルキルスルホンアミド基（メタンスルホンアミド、ブタンスルホンアミド等）、アルキルアミノ基（アミノ、Ｎ，Ｎ−ジメチルアミノ、Ｎ，Ｎ−ジエチルアミノ等）、スルホ基、ホスフォノ基、サルファイト基、スルフィノ基、アルキルスルホニルアミノカルボニル基（メタンスルホニルアミノカルボニル、エタンスルホニルアミノカルボニル等）、アルキルカルボニルアミノスルホニル基（アセトアミドスルホニル、メトキシアセトアミドスルホニル等）、アルキニルアミノカルボニル基（アセトアミドカルボニル、メトキシアセトアミドカルボニル等）、アルキルスルフィニルアミノカルボニル基（メタンスルフィニルアミノカルボニル、エタンスルフィニルアミノカルボニル等）等が挙げられる。又、置換基が二つ以上ある場合は、同じでも異なってもよい。
【０１１４】
Ｒ′及びＲ″は各々、水素原子、ハロゲン原子又は置換基を表し、ハロゲン原子としては、例えば弗素、塩素、臭素原子等が挙げられ、置換基としては、例えばアルキル基、アリール基、シクロアルキル基、アルケニル基、シクロアルケニル基、アルキニル基、アミノ基、アシル基、アシルオキシ基、アシルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、アルキルチオ基、スルホニル基、アルキルスルホニル基、スルフィニル基、シアノ基、複素環基等が挙げられる。複数のＲ′、Ｒ″は同じでも異なってもよい。
【０１１５】
Ｒ′は炭素数２以上が好ましい。Ｒ″は炭素数１〜５が好ましく、更に好ましくは炭素数１である。これらの基は更に置換基を有していてもよく、置換基としては、ハロゲン原子（弗素、塩素、臭素等）、アルキル基（メチル、エチル、プロピルブチル、ペンチル、ｉ−ペンチル、２−エチル−ヘキシル、オクチル、デシル等）、シクロアルキル基（シクロヘキシル、シクロヘプチル等）、アルケニル基（エテニル−２−プロペニル、３−ブテニル、１−メチル−３−プロペニル、３−ペンテニル、１−メチル−３−ブテニル等）、シクロアルケニル基（１−シクロアルケニル基、２−シクロアルケニル基等）、アルキニル基（エチニル、１−プロピニル等）、アルコキシ基（メトキシ、エトキシ、プロポキシ等）、アルキルカルボニルオキシ基（アセチルオキシ等）、アルキルチオ基（メチルチオ、トリフルオロメチルチオ等）、カルボキシル基、アルキルカルボニルアミノ基（アセチルアミノ等）、ウレイド基（メチルアミノカルボニルアミノ等）、アルキルスルホニルアミノ基（メタンスルホニルアミノ等）、アルキルスルホニル基（メタンスルホニル、トリフルオロメタンスルホニル等）、カルバモイル基（カルバモイル、Ｎ，Ｎ−ジメチルカルバモイル、Ｎ−モルホリノカルボニル等）、スルファモイル基（スルファモイル、Ｎ，Ｎ−ジメチルスルファモイル、モルフォリノスルファモイル等）、トリフルオロメチル基、ヒドロキシル基、ニトロ基、シアノ基、アルキルスルホンアミド基（メタンスルホンアミド、ブタンスルホンアミド等）、アルキルアミノ基（アミノ、Ｎ，Ｎ−ジメチルアミノ、Ｎ，Ｎ−ジエチルアミノ等）、スルホ基、ホスホノ基、サルファイト基、スルフィノ基、アルキルスルホニルアミノカルボニル基（メタンスルホニルアミノカルボニル、エタンスルホニルアミノカルボニル等）、アルキルカルボニルアミノスルホニル基（アセトアミドスルホニル、メトキシアセトアミドスルホニル等）、アルキニルアミノカルボニル基（アセトアミドカルボニル、メトキシアセトアミドカルボニル等）、アルキルスルフィニルアミノカルボニル基（メタンスルフィニルアミノカルボニル、エタンスルフィニルアミノカルボニル等）等が挙げられる。
【０１１６】
前記一般式（Ａ）で示される化合物の具体例を以下に示す。
【０１１７】
【化２】

【０１１８】
【化３】

【０１１９】
【化４】

【０１２０】
【化５】

【０１２１】
次に、一般式（Ｓ）中、Ｚは炭素原子と共に３〜１０員の非芳香族環を構成するのに必要な原子群を表すが、該環として具体的に、３員環としてはシクロプロピル、アジリジル、オキシラニル、４員環としてはシクロブチル、シクロブテニル、オキセタニル、アゼチジニル、５員環としてはシクロペンチル、シクロペンテニル、シクロペンタジエニル、テトラヒドロフラニル、ピロリジニル、テトラヒドロチエニル、６員環としてはシクロヘキシル、シクロヘキセニル、シクロヘキサジエニル、テトラヒドロピラニル、ピラニル、ピペリジニル、ジオキサニル、テトラヒドロチオピラニル、ノルカラニル、ノルピナニル、ノルボルニル、７員環としてはシクロヘプチル、シクロヘプチニル、シクロヘプタジエニル、８員環としてはシクロオクタニル、シクロオクテニル、シクロオクタジエニル、シクロオクタトリエニル、９員環としてはシクロノナニル、シクロノネニル、シクロノナジエニル、シクロノナトリエニル、１０員環としてはシクロデカニル、シクロデケニル、シクロデカジエニル、シクロデカトリエニル等の各基が挙げられる。好ましくは３〜６員環であり、より好ましくは５〜６員環であり、最も好ましくは６員環であり、その中でもヘテロ原子を含まない炭化水素環が好ましい。
【０１２２】
該環はスピロ原子を通じて他の環とスピロ結合を形成してもよいし、芳香族環を含む他の環と如何様に縮環してもよい。又、環上には任意の置換基を有することができる。該置換基として具体的には、ハロゲン原子（弗素、塩素、臭素等）、アルキル基（メチル、エチル、プロピル、ブチル、ペンチル、ｉ−ペンチル、２−エチル−ヘキシル、オクチル、デシル等）、シクロアルキル基（シクロヘキシル、シクロヘプチル等）、アルケニル基（エテニル−２−プロペニル、３−ブテニル、１−メチル−３−プロペニル、３−ペンテニル、１−メチル−３−ブテニル等）、シクロアルケニル基（１−シクロアルケニル基、２−シクロアルケニル基等）、アルキニル基（エチニル、１−プロピニル等）、アルコキシ基（メトキシ、エトキシ、プロポキシ等）、アルキルカルボニルオキシ基（アセチルオキシ等）、アルキルチオ基（メチルチオ、トリフルオロメチルチオ等）、カルボキシル基、アルキルカルボニルアミノ基（アセチルアミノ等）、ウレイド基（メチルアミノカルボニルアミノ等）、アルキルスルホニルアミノ基（メタンスルホニルアミノ等）、アルキルスルホニル基（メタンスルホニル、トリフルオロメタンスルホニル等）、カルバモイル基（カルバモイル、Ｎ，Ｎ−ジメチルカルバモイル、Ｎ−モルホリノカルボニル等）、スルファモイル基（スルファモイル、Ｎ，Ｎ−ジメチルスルファモイル、モルホリノスルファモイル等）、トリフルオロメチル基、ヒドロキシル基、ニトロ基、シアノ基、アルキルスルホンアミド基（メタンスルホンアミド、ブタンスルホンアミド等）、アルキルアミノ基（アミノ、Ｎ，Ｎ−ジメチルアミノ、Ｎ，Ｎ−ジエチルアミノ等）、スルホ基、ホスホノ基、サルファイト基、スルフィノ基、アルキルスルホニルアミノカルボニル基（メタンスルホニルアミノカルボニル、エタンスルホニルアミノカルボニル等）、アルキルカルボニルアミノスルホニル基（アセトアミドスルホニル、メトキシアセトアミドスルホニル等）、アルキニルアミノカルボニル基（アセトアミドカルボニル、メトキシアセトアミドカルボニル等）、アルキルスルフィニルアミノカルボニル基（メタンスルフィニルアミノカルボニル、エタンスルフィニルアミノカルボニル等）等が挙げられる。又、置換基が二つ以上ある場合は、同じでも異なってもよい。特に好ましい置換基はアルキル基である。Ｒ_０′、Ｒ_０″は水素原子、アルキル基、アリール基又は複素環基を表すが、アルキル基として具体的には炭素数１〜１０のアルキル基が好ましい。具体例としてはメチル、エチル、プロピル、ｉ−プロピル、ブチル、ｔ−ブチル、ペンチル、ｉ−ペンチル、２−エチル−ヘキシル、オクチル、デシルシクロヘキシル、シクロヘプチル、１−メチルシクロヘキシル、エテニル−２−プロペニル、３−ブテニル、１−メチル−３−プロペニル、３−ペンテニル、１−メチル−３−ブテニル、１−シクロアルケニル、２−シクロアルケニル、エチニル、１−プロピニル等が挙げられる。より好ましくはメチル、エチル、ｉ−プロピル、ｔ−ブチル、シクロヘキシル、１−メチルシクロヘキシル等が挙げられる。好ましくはメチル、ｔ−ブチル、１−メチルシクロヘキシルであり、最も好ましくはメチルである。
【０１２３】
アリール基として具体的には、フェニル基、ナフチル基、アントラニル基等が挙げられる。複素環基として具体的には、ピリジル、キノリル、イソキノリル、イミダゾリル、ピラゾリル、トリアゾリル、オキサゾリル、チアゾリル、オキサジアゾリル、チアジアゾリル、テトラゾリル等の芳香族複素環基やピペリジノ、モルホリノ、テトラヒドロフリル、テトラヒドロチエニル、テトラヒドロピラニル等の非芳香族複素環基が挙げられる。
【０１２４】
これらの基は更に置換基を有してもよく、該置換基としては前述の環上の置換基と同様の基を挙げることができる。複数のＲ_０′、Ｒ_０″は同じでも異なってもよいが、最も好ましくは全てがメチル基の場合である。
【０１２５】
Ｒｘは水素原子又はアルキル基を表すが、アルキル基として具体的には炭素数１〜１０のアルキル基が好ましい。具体例としてはメチル、エチル、プロピル、ｉ−プロピル、ブチル、ｔ−ブチル、ペンチル、ｉ−ペンチル、２−エチル−ヘキシル、オクチル、デシル、シクロヘキシル、シクロヘプチル、１−メチルシクロヘキシル、エテニル−２−プロペニル、３−ブテニル、１−メチル−３−プロペニル、３−ペンテニル、１−メチル−３−ブテニル、１−シクロアルケニル基、２−シクロアルケニル基、エチニル、１−プロピニル等が挙げられる。より好ましくはメチル、エチル、ｉ−プロピル等が挙げられる。好ましくはＲｘは水素原子である。
【０１２６】
Ｑ_０はベンゼン環上に置換可能な基を表すが、具体的には炭素数１〜２５のアルキル基（メチル、エチル、プロピル、ｉ−プロピル、ｔ−ブチル、ペンチル、ヘキシル、シクロヘキシル等）、ハロゲン化アルキル基（トリフルオロメチル、パーフルオロオクチル等）、シクロアルキル基（シクロヘキシル、シクロペンチル等）、アルキニル基（プロパルギル等）、グリシジル基、アクリレート基、メタクリレート基、アリール基（フェニル等）、複素環基（ピリジル、チアゾリル、オキサゾリル、イミダゾリル、フリル、ピロリル、ピラジニル、ピリミジニル、ピリダジニル、セレナゾリル、スリホラニル、ピペリジニル、ピラゾリル、テトラゾリル等）、ハロゲン原子（塩素、臭素、沃素、弗素等）、アルコキシ基（メトキシ、エトキシ、プロピルオキシ、ペンチルオキシ、シクロペンチルオキシ、ヘキシルオキシ、シクロヘキシルオキシ等）、アリールオキシ基（フェノキシ等）、アルコキシカルボニル基（メチルオキシカルボニル、エチルオキシカルボニル、ブチルオキシカルボニル等）、アリールオキシカルボニル基（フェニルオキシカルボニル等）、スルホンアミド基（メタンスルホンアミド、エタンスルホンアミド、ブタンスルホンアミド、ヘキサンスルホンアミド、シクロヘキサンスルホンアミド、ベンゼンスルホンアミド等）、スルファモイル基（アミノスルホニル、メチルアミノスルホニル、ジメチルアミノスルホニル、ブチルアミノスルホニル、ヘキシルアミノスルホニル、シクロヘキシルアミノスルホニル、フェニルアミノスルホニル、２−ピリジルアミノスルホニル等）、ウレタン基（メチルウレイド、エチルウレイド、２−ピリジルウレイド等）、アシル基（アセチル、プロピオニル、ブタノイル、ヘキサノイル、シクロヘキサノイル、ベンゾイル、ピリジノイル等）、カルバモイル基（アミノカルボニル、メチルアミノカルボニル、ジメチルアミノカルボニル、プロピルアミノカルボニル、ペンチルアミノカルボニル、シクロヘキシルアミノカルボニル、フェニルアミノカルボニル、２−ピリジルアミノカルボニル等）、アミド基（アセトアミド、プロピオンアミド、ブタンアミド、ヘキサンアミド、ベンズアミド等）、スルホニル基（メチルスルホニル、エチルスルホニル、ブチルスルホニル、シクロヘキシルスルホニル、フェニルスルホニル、２−ピリジルスルホニル等）、アミノ基（アミノ、エチルアミノ、ジメチルアミノ、ブチルアミノ、シクロペンチルアミノ、アニリノ、２−ピリジルアミノ等）、シアノ基、ニトロ基、スルホ基、カルボキシル基、ヒドロキシル基、オキザモイル基等を挙げることができる。又、これらの基は、更にこれらの基で置換されてもよい。ｎ及びｍは０〜２の整数を表すが、最も好ましくはｎ、ｍ共に０の場合である。
【０１２７】
以下に本発明の一般式（Ｓ）で表される化合物の具体例を列記する。
【０１２８】
【化６】

【０１２９】
【化７】

【０１３０】
【化８】

【０１３１】
【化９】

【０１３２】
【化１０】

【０１３３】
【化１１】

【０１３４】
本発明では、米国特許３，５８９，９０３号、同４，０２１，２４９号もしくは英国特許１，４８６，１４８号及び特開昭５１−５１９３３号、同５０−３６１１０号、同５０−１１６０２３号、同５２−８４７２７号もしくは特公昭５１−３５７２７号に記載されたポリフェノール化合物、例えば２，２′−ジヒドロキシ−１，１′−ビナフチル、６，６′−ジブロモ−２，２′−ジヒドロキシ−１，１′−ビナフチル等の米国特許３，６７２，９０４号に記載されたビスナフトール類、更に、例えば４−ベンゼンスルホンアミドフェノール、２−ベンゼンスルホンアミドフェノール、２，６−ジクロロ−４−ベンゼンスルホンアミドフェノール、４−ベンゼンスルホンアミドナフトール等の米国特許３，８０１，３２１号に記載されるようなスルホンアミドフェノール又はスルホンアミドナフトール類も還元剤として用いることができる。
【０１３５】
上記一般式（Ａ）及び一般式（Ｓ）で表される化合物を初めとする還元剤の使用量は、好ましくは銀１モル当たり１×１０^−２〜１０モル、特に１×１０^−２〜１．５モルである。
【０１３６】
光熱写真材料に使用される還元剤の量は、有機銀塩や還元剤の種類、その他の添加剤によって変化するが、一般的には有機銀塩１モル当たり０．０５〜１０モル、好ましくは０．１〜３モルが適当である。この範囲内において、上記還元剤は２種以上併用されてもよい。本発明においては、還元剤を塗布直前に感光性ハロゲン化銀及び有機銀塩粒子及び溶媒から成る感光乳剤溶液に添加混合して塗布した方が、停滞時間による写真性能変動が小さく好ましい場合がある。
【０１３７】
上述した還元剤は２種以上併用されてもよい。本発明においては、前記還元剤を塗布直前に感光性ハロゲン化銀及び有機銀塩粒子及び溶媒からなる感光乳剤溶液に添加混合して塗布した方が、停滞時間による写真性能変動が小さく好ましい場合がある。
【０１３８】
尚、還元剤の補助剤として、ＥＰ１，０９６，３１０号に記載されるトリフェニルホスフィンオキシド等のように還元剤の水酸基の水素と水素結合を形成し得る化合物を併用することも好ましい。
【０１３９】
（感光性ハロゲン化銀粒子）
本発明の銀塩光熱写真材料に用いられる感光性ハロゲン化銀粒子（単にハロゲン化銀粒子とも言う）について説明する。尚、本発明における感光性ハロゲン化銀粒子とは、ハロゲン化銀結晶の固有の性質として本質的に光吸収することができ、又は人為的に物理化学的な方法により可視光ないし赤外光を吸収することができ、かつ紫外光領域から赤外光領域の光波長範囲内の何れかの領域の光を吸収した時に、当該ハロゲン化銀結晶内及び／又は結晶表面において、物理化学的変化が起こり得るように処理製造されたハロゲン化銀結晶粒子を言う。
【０１４０】
本発明に用いられるハロゲン化銀粒子自体は、Ｐ．Ｇｌａｆｋｉｄｅｓ著：Ｃｈｉｍｉｅ ｅｔ Ｐｈｙｓｉｑｕｅ Ｐｈｏｔｏｇｒａｐｈｉｑｕｅ（Ｐａｕｌ Ｍｏｎｔｅｌ社刊，１９６７年）、Ｇ．Ｆ．Ｄｕｆｆｉｎ著：Ｐｈｏｔｏｇｒａｐｈｉｃ Ｅｍｕｌｓｉｏｎ Ｃｈｅｍｉｓｔｒｙ（Ｔｈｅ Ｆｏｃａｌ Ｐｒｅｓｓ刊、１９６６年）、Ｖ．Ｌ．Ｚｅｌｉｋｍａｎ ｅｔ ａｌ著：Ｍａｋｉｎｇ ａｎｄ Ｃｏａｔｉｎｇ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｅｍｕｌｓｉｏｎ（Ｔｈｅ Ｆｏｃａｌ Ｐｒｅｓｓ刊，１９６４年）等に記載された方法を用いてハロゲン化銀粒子乳剤として調製することができる。
【０１４１】
即ち、酸性法、中性法、アンモニア法等の何れでもよく、又可溶性銀塩と可溶性ハロゲン塩を反応させる形成としては、片側混合法、同時混合法、それらの組合せ等の何れを用いてもよいが、上記方法の中でも形成条件をコントロールしつつハロゲン化銀粒子を調製する、所謂コントロールドダブルジェット法が好ましい。ハロゲン組成としては特に制限はなく、塩化銀、塩臭化銀、塩沃臭化銀、臭化銀、沃臭化銀、沃化銀の何れでもよいが、医用イメージング材料用には臭化銀又は沃臭化銀が好ましい。沃臭化銀の場合は、沃度の含有量は０．０２〜６モル％／Ａｇ１モルの範囲であることが好ましい。沃度はハロゲン化銀粒子全体に分布するように含有させても、ハロゲン化銀粒子の特定個所、例えば粒子の中心部の沃度の濃度を高くし表面近傍における濃度を低く又は実質上ゼロとなるようなコア／シェル型構造にしてもよい。
【０１４２】
粒子形成は、通常、ハロゲン化銀種粒子（核）生成と粒子成長の２段階に分けられ、一度にこれらを連続的に行う方法でもよく、又核（種粒子）形成と粒子成長を分離して行う方法でもよい。粒子形成条件であるｐＡｇ、ｐＨ等をコントロールして粒子形成を行うコントロールドダブルジェット法が粒子形状やサイズのコントロールが出来るので好ましい。例えば、核生成と粒子成長を分離して行う方法を行う場合には、先ず可溶性銀塩と可溶性ハロゲン塩をゼラチン水溶液中で均一、急速に混合させ核（種粒子）生成（核生成工程）した後、コントロールされたｐＡｇ、ｐＨ等のもとで、可溶性銀塩と可溶性ハロゲン塩を供給しつつ、粒子成長させる粒子成長工程によりハロゲン化銀粒子を調製する。粒子形成後、脱塩工程により不要な塩類等をヌードル法、フロキュレーション法、限外濾過法、電気透析法等の公知の脱塩法により除くことで所望のハロゲン化銀乳剤を得ることが出来る。
【０１４３】
本発明に用いるハロゲン化銀粒子は、異なる粒経のものを混合することが好ましく、平均粒径は０．０２μｍ未満の粒子を計測の対象外とした時の値として、０．０４０μｍ以下及び／又は０．０７０〜０．１００μｍのハロゲン化銀粒子数が、全体の１０〜３０％の範囲が好ましい。尚、ここでいう粒径とは、ハロゲン化銀粒子が立方体あるいは八面体の、いわゆる正常晶である場合には、ハロゲン化銀粒子の稜の長さを言う。又、ハロゲン化銀粒子が平板状粒子である場合には、主表面の投影面積と同面積の円像に換算した時の直径をいう。
【０１４４】
ハロゲン化銀粒子は単分散であることが好ましい。ここで言う単分散とは、下記式で求められる粒径の変動係数が３０％以下のことを言う。好ましくは２０％以下であり、更に好ましくは１５％以下である。
【０１４５】
粒径の変動係数％＝（粒径の標準偏差／粒径の平均値）×１００
ハロゲン化銀粒子の形状としては立方体、八面体、１４面体粒子、平板状粒子、球状粒子、棒状粒子、ジャガイモ状粒子などを挙げることができるが、これらの内、特に立方体、八面体、１４面体、平板状ハロゲン化銀粒子が好ましい。
【０１４６】
平板状ハロゲン化銀粒子を用いる場合の平均アスペクト比は、好ましくは１．５〜１００、より好ましくは２〜５０以下がよい。これらは米国特許５，２６４，３３７号、同５，３１４，７９８号、同５，３２０，９５８号等に記載されており、容易に目的の平板状粒子を得ることができる。更に、ハロゲン化銀粒子のコーナーが丸まった粒子も好ましく用いることができる。
【０１４７】
ハロゲン化銀粒子外表面の晶癖については特に制限はないが、ハロゲン化銀粒子表面への増感色素の吸着反応において、晶癖（面）選択性を有する分光増感色素を使用する場合には、その選択性に適応する晶癖を相対的に高い割合で有するハロゲン化銀粒子を使用することが好ましい。例えば、ミラー指数〔１００〕の結晶面に選択的に吸着する増感色素を使用する場合には、ハロゲン化銀粒子外表面において〔１００〕面の占める割合が高いことが好ましく、この割合が５０％以上、更には７０％以上、特に８０％以上であることが好ましい。尚、ミラー指数〔１００〕面の比率は、増感色素の吸着における〔１１１〕面と〔１００〕面との吸着依存性を利用したＴ．Ｔａｎｉ，Ｊ．Ｉｍａｇｉｎｇ Ｓｃｉ．，２９，１６５（１９８５年）により求めることができる。
【０１４８】
本発明に用いられるハロゲン化銀粒子は、粒子形成時に平均分子量５万以下の低分子量ゼラチンを用いて調製することが好ましいが、特にハロゲン化銀粒子の核形成時に用いることが好ましい。低分子量ゼラチンは、平均分子量５万以下のものであり、好ましくは２，０００〜４０，０００、更には５，０００〜２５，０００である。ゼラチンの平均分子量はゲル濾過クロマトグラフィーで測定することができる。低分子量ゼラチンは、通常用いられる平均分子量１０万程度のゼラチン水溶液にゼラチン分解酵素を加えて酵素分解したり、酸又はアルカリを加えて加熱し加水分解したり、大気圧下又は加圧下での加熱により熱分解したり、超音波照射して分解したり、それらの方法を併用したりして得られる。
【０１４９】
核形成時の分散媒の濃度は５質量％以下が好ましく、０．０５〜３．０質量％の低濃度で行うのがより有効である。
【０１５０】
ハロゲン化銀粒子は、該粒子形成時に下記一般式（ＡＯ）で示されるポリエチレンオキシド化合物を用いることが好ましい。
【０１５１】
一般式（ＡＯ）
ＹＯ（ＣＨ_２ＣＨ_２Ｏ）_ｍ（ＣＨ（ＣＨ_３）ＣＨ_２Ｏ）_ｐ（ＣＨ_２ＣＨ_２Ｏ）_ｎＹ
式中、Ｙは水素原子、−ＳＯ_３Ｍ、又は−ＣＯ−Ｂ−ＣＯＯＭを表し、Ｍは水素原子、アルカリ金属原子、アンモニウム基又は炭素原子数５以下のアルキル基にて置換されたアンモニウム基を表し、Ｂは有機２塩基性酸を形成する鎖状又は環状の基を表す。ｍ及びｎは各々０〜５０をｐは１〜１００を表す。
【０１５２】
上記ポリエチレンオキシド化合物は、ハロゲン化銀写真感光材料を製造するに際し、ゼラチン水溶液を製造する工程、ゼラチン溶液に水溶性ハロゲン化物及び水溶性銀塩を添加する工程、乳剤を支持体上に塗布する工程等、乳剤原料を撹拌したり、移動したりする場合の著しい発泡に対する消泡剤として好ましく用いられて来たものであり、消泡剤として用いる技術は、例えば特開昭４４−９４９７号に記載されている。上記ポリエチレンオキシド化合物は核形成時の消泡剤としても機能する。
【０１５３】
上記ポリエチレンオキシド化合物は、銀に対して１質量％以下で用いるのが好ましく、より好ましくは０．０１〜０．１質量％で用いる。
【０１５４】
上記一般式（ＡＯ）のポリエチレンオキシド化合物は核形成時に存在していればよく、核形成前の分散媒中に予め加えておくのが好ましいが、核形成中に添加してもよいし、核形成時に使用する銀塩水溶液やハライド水溶液に添加して用いてもよい。好ましくは、ハライド水溶液もしくは両方の水溶液に０．０１〜２．０質量％で添加して用いることである。又、核形成工程の少なくとも５０％に亘る時間で存在させるのが好ましく、更に好ましくは７０％以上に亘る時間で存在きせる。上記ポリエチレンオキシド化合物は、粉末で添加しても、メタノール等の溶媒に溶かして添加してもよい。
【０１５５】
尚、核形成時の温度は５〜６０℃、好ましくは１５〜５０℃であり、一定の温度であっても、昇温パターン（核形成開始時の温度が２５℃で、核形成中、徐々に温度を挙げ、核形成終了時の温度が４０℃の様な場合）や、その逆のパターンであっても、上記温度範囲内で制御するのが好ましい。
【０１５６】
核形成に用いる銀塩水溶液及びハライド水溶液の濃度は３．５ｍｏｌ（モル）／Ｌ（リットル）以下が好ましく、更には０．０１〜２．５ｍｏｌ／Ｌの低濃度域で使用されるのが好ましい。核形成時の銀イオンの添加速度は、反応液１Ｌ当たり１．５×１０^−３〜３．０×１０^−１モル／分が好ましく、更に好ましくは３．０×１０^−３〜８．０×１０^−２モル／分である。
【０１５７】
核形成時のｐＨは１．７〜１０の範囲に設定できるが、アルカリ側のｐＨでは形成する核の粒径分布を広げるため好ましくはｐＨ２〜６である。又、核形成時のｐＢｒは０．０５〜３．０程度、好ましくは１．０〜２．５、更には１．５〜２．０がより好ましい。
【０１５８】
核形成後に複素環式化合物をハロゲン化銀粒子の内部に含有させることが感度及び画像保存性上好ましい。ここで用いられる複素環式化合物としては、イミダゾール、ピラゾール、ピリジン、ピリミジン、ピラジン、ピリダジン、トリアゾール、トリアジン、インドール、インダゾール、プリン、チアジアゾール、オキサジアゾール、キノリン、フタラジン、ナフチリジン、キノキサリン、キナゾリン、シンノリン、プテリジン、アクリジン、フェナントロリン、フェナジン、テトラゾール、チアゾール、オキサゾール、ベンズイミダゾール、ベンゾオキサゾール、ベンゾチアゾール、インドレニン、テトラザインデン等であり、好ましくはイミダゾール、ピリジン、ピリミジン、ピラジン、ピリダジン、トリアゾール、トリアジン、チアジアゾール、オキサジアゾール、キノリン、フタラジン、ナフチリジン、キノキサリン、キナゾリン、シンノリン、テトラゾール、チアゾール、オキサゾール、ベンズイミダゾール、ベンゾオキサゾール、ベンゾチアゾール、テトラザインデン等である。
【０１５９】
尚、上記の複素環式化合物は置換基を有してもよく、置換基として好ましくはアルキル基、アルケニル基、アリール基、アルコキシ基、アリールオキシ基、アシルオキシ基、アシル基、アルコキシカルボニル基、アリールオキシカルボニル基、アシルオキシ基、アシルアミノ基、アルコキシカルボニルアミノ基、アリールオキシカルボニルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、スルホニル基、ウレイド基、リン酸アミド基、ハロゲン原子、シアノ基、スルホ基、カルボキシル基、ニトロ基、複素環基であり、より好ましくはアルキル基、アリール基、アルコキシ基、アリールオキシ基、アシル基、アシルアミノ基、アルコキシカルボニルアミノ基、アリールオキシカルボニルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、ウレイド基、燐酸アミド基、ハロゲン原子、シアノ基、ニトロ基、複素環基であり、更に好ましくはアルキル基、アリール基、アルコキシ基、アリールオキシ基、アシル基、アシルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、ハロゲン原子、シアノ基、ニトロ基、複素環基である。
【０１６０】
ハロゲン化銀粒子は如何なる方法で画像形成層（感光層）に添加されてもよく、この時、ハロゲン化銀粒子は還元可能な銀源（脂肪族カルボン酸銀塩）に近接するように配置するのが好ましい。
【０１６１】
ハロゲン化銀は予め調製しておき、これを脂肪族カルボン酸銀塩粒子を調製するための溶液に添加するのが、ハロゲン化銀調製工程と脂肪族カルボン酸銀塩粒子調製工程を分離して扱えるので製造コントロール上も好ましいが、英国特許１，４４７，４５４号に記載されている様に、脂肪族カルボン酸銀塩粒子を調製する際にハライドイオン等のハロゲン成分を脂肪族カルボン酸銀塩形成成分と共存させ、これに銀イオンを注入することで脂肪族カルボン酸銀塩粒子の生成とほぼ同時に生成させることも出来る。又、脂肪族カルボン酸銀塩にハロゲン含有化合物を作用させ、脂肪族カルボン酸銀塩のコンバージョンによりハロゲン化銀粒子を調製することも可能である。即ち、予め調製された脂肪族カルボン酸銀塩の溶液もしくは分散液、又は脂肪族カルボン酸銀塩を含むシート材料にハロゲン化銀形成成分を作用させて、脂肪族カルボン酸銀塩の一部を感光性ハロゲン化銀に変換することもできる。
【０１６２】
ただし、本発明の感光性ハロゲン化銀粒子とは、前記脂肪カルボン酸銀塩と直接関わり無く、前記脂肪カルボン酸銀塩とは別個に予め調製したハロゲン化銀粒子を指す。
【０１６３】
ハロゲン化銀粒子形成成分としては、無機ハロゲン化合物、オニウムハライド類、ハロゲン化炭化水素類、Ｎ−ハロゲン化合物、その他の含ハロゲン化合物があり、その具体例については米国特許４，００９，０３９号、同３，４５７，０７５号、同４，００３，７４９号、英国特許１，４９８，９５６号及び特開昭５３−２７０２７号、同５３−２５４２０号に詳説される金属ハロゲン化物、ハロゲン化アンモニウム等の無機ハロゲン化物、例えばトリメチルフェニルアンモニウムブロミド、セチルエチルジメチルアンモニウムブロミド、トリメチルベンジルアンモニウムブロミドの様なオニウムハライド類、例えばヨードホルム、ブロモホルム、四塩化炭素、２−ブロモ−２−メチルプロパン等のハロゲン化炭化水素類、Ｎ−ブロモ琥珀酸イミド、Ｎ−ブロモフタルイミド、Ｎ−ブロモアセトアミド等のＮ−ハロゲン化合物、その他、例えば塩化トリフェニルメチル、臭化トリフェニルメチル、２−ブロモ酢酸、２−ブロモエタノール、ジクロロベンゾフェノン等がある。この様に、ハロゲン化銀を有機酸銀とハロゲンイオンとの反応により有機酸銀塩中の銀の一部又は全部をハロゲン化銀に変換することによって調製することもできる。又、別途調製したハロゲン化銀に脂肪族カルボン酸銀塩の一部をコンバージョンすることで製造したハロゲン化銀粒子を併用してもよい。
【０１６４】
これらのハロゲン化銀粒子は、別途調製したハロゲン化銀粒子、脂肪族カルボン酸銀塩のコンバージョンによるハロゲン化銀粒子とも、脂肪族カルボン酸銀塩１モルに対し０．００１〜０．７モル、好ましくは０．０３〜０．５モル使用するのが好ましい。
【０１６５】
ハロゲン化銀粒子には、元素周期表の６〜１１族に属する遷移金属のイオンを含有することが好ましい。上記の金属としては、Ｗ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｒｕ、Ｒｈ、Ｐｄ、Ｒｅ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕが好ましい。これらは１種類でも同種又は異種の金属錯体を２種以上併用してもよい。これらの金属イオンは、金属塩をそのままハロゲン化銀に導入してもよいが、金属錯体又は錯体イオンの形でハロゲン化銀に導入できる。好ましい含有率は銀１モルに対し１×１０^−９〜１×１０^−２モルの範囲が好ましく、１×１０^−８〜１×１０^−４の範囲がより好ましい。遷移金属錯体又は錯体イオンは下記一般式で表されるものが好ましい。
【０１６６】
一般式〔ＭＬ_６〕^ｍ
式中、Ｍは元素周期表の６〜１１族の元素から選ばれる遷移金属であり、特にＯｓとＲｕが好ましい。Ｌは配位子を表し、ｍは０、−、２−、３−又は４−を表す。Ｌで表される配位子の具体例としては、ハロゲンイオン（弗素、塩素、臭素、沃素イオン）、シアナイド、シアナート、チオシアナート、セレノシアナート、テルロシアナート、アジド及びアコの各配位子、ニトロシル、チオニトロシル等が挙げられ、好ましくはアコ、ニトロシル及びチオニトロシル等である。アコ配位子が存在する場合には、配位子の一つ又は二つを占めることが好ましい。Ｌは同一でもよく、異なってもよい。
【０１６７】
これらの金属のイオン又は錯体イオンを提供する化合物は、ハロゲン化銀粒子形成時に添加し、ハロゲン化銀粒子中に組み込まれることが好ましく、ハロゲン化銀粒子の調製、つまり核形成、成長、物理熟成、化学増感の前後のどの段階で添加してもよいが、特に核形成、成長、物理熟成の段階で添加するのが好ましく、更には核形成、成長の段階で添加するのが好ましく、最も好ましくは核形成の段階で添加する。添加に際しては、数回に亘って分割して添加してもよく、ハロゲン化銀粒子中に均一に含有させることもできるし、特開昭６３−２９６０３号、特開平２−３０６２３６号、同３−１６７５４５号、同４−７６５３４号、同６−１１０１４６号、同５−２７３６８３号等に記載される様に、粒子内に分布を持たせて含有させることもできる。
【０１６８】
これらの金属化合物は、水又は適当な有機溶媒（アルコール類、エーテル類、グリコール類、ケトン類、エステル類、アミド類）に溶解して添加することができるが、例えば金属化合物の粉末の水溶液もしくは金属化合物と塩化ナトリウム、塩化カリウムとを一緒に溶解した水溶液を、粒子形成中の水溶性銀塩溶液又は水溶性ハライド溶液中に添加しておく方法、あるいは銀塩溶液とハライド溶液が同時に混合される時、第３の水溶液として添加し、３液同時混合の方法でハロゲン化銀粒子を調製する方法、粒子形成中に必要量の金属化合物の水溶液を反応容器に投入する方法、あるいはハロゲン化銀調製時に、予め金属のイオン又は錯体イオンをドープしてある別のハロゲン化銀粒子を添加して溶解させる方法等がある。特に、金属化合物の粉末の水溶液もしくは金属化合物と塩化ナトリウム、塩化カリウムとを一緒に溶解した水溶液を水溶性ハライド溶液に添加する方法が好ましい。粒子表面に添加する時には、粒子形成直後又は物理熟成時途中もしくは終了時又は化学熟成時に必要量の金属化合物の水溶液を反応容器に投入することもできる。
【０１６９】
別途調製した感光性ハロゲン化銀粒子は、ヌードル法、フロキュレーション法、限外濾過法、電気透析法等の公知の脱塩法により脱塩することができるが、脱塩しないで用いることもできる。
【０１７０】
尚、本発明においては、ハロゲン化銀粒子の粒経は、核形成後の成長時の温度や成長時間を変化させるなど、当写真業界で既知の方法で任意に制御することができる。
【０１７１】
（脂肪族カルボン酸銀塩）
脂肪族カルボン酸銀塩は還元可能な銀源であり、炭素数１０〜３０、好ましくは１５〜２５の脂肪族カルボン酸の銀塩が好ましい。好適な銀塩の例としては以下のものが挙げられる。
【０１７２】
没食子酸、蓚酸、ベヘン酸、ステアリン酸、アラキジン酸、パルミチン酸、ラウリン酸等の銀塩。これらの内、好ましい銀塩としてはベヘン酸銀、アラキジン酸銀及びステアリン酸銀が挙げられる。又、本発明においては脂肪族カルボン酸銀塩が２種以上混合されていることが、現像性を上げ高濃度、高コントラストの銀画像を形成する上で好ましく、例えば２種以上の脂肪族カルボン酸混合物に銀イオン溶液を混合して調製することが好ましいが、ベヘン酸銀塩のモル比率が８０％以上であることが好ましい。
【０１７３】
脂肪族カルボン酸銀塩化合物は、水溶性銀化合物と銀と錯形成する化合物を混合することにより得られるが、正混合法、逆混合法、同時混合法、特開平９−１２７６４３号に記載される様なコントロールドダブルジェット法等が好ましく用いられる。例えば、有機酸にアルカリ金属塩（水酸化ナトリウム、水酸化カリウム等）を加えて有機酸アルカリ金属塩ソープ（ベヘン酸ナトリウム、アラキジン酸ナトリウム等）を作製した後に、コントロールドダブルジェット法により、前記ソープと硝酸銀などを混合して脂肪族カルボン酸銀塩の結晶を作製する。その際にハロゲン化銀粒子を混在させてもよい。
【０１７４】
脂肪族カルボン酸銀塩においては、平均円相当径が０．０５〜０．８μｍであり、平均厚さが０．００５〜０．０７μｍであることが好ましく、特に好ましくは平均円相当径が０．２〜０．５μｍであり、平均厚さ０．０１〜０．０５μｍである。平均円相当径が０．０５μｍ未満では透明性には優れるが、画像保存性が悪く、平均円相当径が０．８μｍを超えると失透が激しい。平均厚さが０．００５μｍ未満では、表面積が大きく現像時の銀イオン供給が急激に行われ、特に低濃度部では銀画像に使われずに、膜中に残存する銀イオンが多量に存在する結果、画像保存性が著しく劣化する。平均厚さが０．０７μｍを超えると表面積が小さくなり、画像安定性は向上するが、現像時の銀供給が遅く、特に高濃度部での現像銀形状の不均一を招き、結果最高濃度が低くなり易い。
【０１７５】
平均円相当径を求めるには、分散後の脂肪族カルボン酸銀塩を希釈してカーボン支持膜付きグリッド上に分散し、透過型電子顕微鏡（日本電子製：２０００ＦＸ型）、直接倍率５，０００倍にて撮影を行った。スキャナにてネガをデジタル画像として取り込み、適当な画像処理ソフトを用いて粒径（円相当径）を３００個以上測定し、平均粒径を算出する。
【０１７６】
平均厚さを求めるには、下記に示すようなＴＥＭ（透過型電子顕微鏡）を用いた方法により算出する。
【０１７７】
まず、支持体上に塗布された画像形成層を接着剤により適当なホルダーに貼り付け、支持体面と垂直な方向にダイヤモンドナイフを用いて厚さ０．１〜０．２μｍの超薄切片を作製する。作製された超薄切片を、銅メッシュに支持させ、グロー放電により親水化されたカーボン膜上に移し、液体窒素により−１３０℃以下に冷却しながら、ＴＥＭを用いて倍率５，０００〜４０，０００倍にて明視野像を観察し、画像はフィルム、イメージングプレート、ＣＣＤカメラ等に素早く記録する。この際、観察される視野としては、切片に破れや弛みがない部分を適宜選択することが好ましい。
【０１７８】
カーボン膜としては極く薄いコロジオン、ホルムバールなど有機膜に支持されたものを使用することが好ましく、更に好ましくは岩塩基板上に形成し基板を溶解除去して得るか、又は、上記有機膜を有機溶媒、イオンエッチングにより除去して得られたカーボン単独の膜である。ＴＥＭの加速電圧としては８０〜４００ｋＶが好ましく、特に好ましくは８０〜２００ｋＶである。
【０１７９】
その他、電子顕微鏡観察技法、及び試料作製技法の詳細については「日本電子顕微鏡学会関東支部編／医学・生物学電子顕微鏡観察法」（丸善）、「日本電子顕微鏡学会関東支部編／電子顕微鏡生物試料作製法」（丸善）を、それぞれ参考にすることができる。
【０１８０】
適当な媒体に記録されたＴＥＭ画像は、画像１枚を少なくとも１０２４画素×１０２４画素、好ましくは２０４８画素×２０４８画素以上に分解し、コンピュータによる画像処理を行うことが好ましい。画像処理を行うためには、フィルムに記録されたアナログ画像はスキャナなどでデジタル画像に変換し、シェーディング補正、コントラスト・エッジ強調などを必要に応じ施すことが好ましい。その後、ヒストグラムを作製し、２値化処理によって脂肪族カルボン酸銀に相当する箇所を抽出する。
【０１８１】
上記抽出した脂肪族カルボン酸銀塩粒子の厚さを３００個以上適当なソフトでマニュアル測定し、平均値を求める。
【０１８２】
上記の形状を有する脂肪族カルボン酸銀塩粒子を得る方法は特に限定されないが、有機酸アルカリ金属塩ソープ形成時の混合状態及び／又は前記ソープに硝酸銀を添加する際の混合状態などを良好に保つことや、ソープに対する有機酸の割合、ソープと反応する硝酸銀の割合を最適にすることなどが有効である。
【０１８３】
本発明の脂肪族カルボン酸銀塩粒子（平均円相当径が０．０５〜０．８μｍであり、かつ平均厚さが０．００５〜０．０７μｍの脂肪族カルボン酸銀塩粒子を言う）は、必要に応じバインダーや界面活性剤などと共に予備分散した後、メディア分散機又は高圧ホモジナイザなどで分散粉砕することが好ましい。上記予備分散にはアンカー型、プロペラ型等の一般的撹拌機や高速回転遠心放射型撹拌機（ディゾルバ）、高速回転剪断型撹拌機（ホモミキサ）を使用できる。
【０１８４】
又、上記メディア分散機としては、ボールミル、遊星ボールミル、振動ボールミルなどの転動ミルや、媒体撹拌ミルであるビーズミル、アトライター、その他バスケットミル等を用いることが可能であり、高圧ホモジナイザとしては壁、プラグなどに衝突するタイプ、液を複数に分けてから高速で液同士を衝突させるタイプ、細いオリフィスを通過させるタイプ等、様々なタイプを用いることができる。
【０１８５】
メディア分散時に使用されるセラミックスビーズに用いられるセラミックスとしては、例えばＡｌ_２Ｏ_３、ＢａＴｉＯ_３、ＳｒＴｉＯ_３、ＭｇＯ、ＺｒＯ、ＢｅＯ、Ｃｒ_２Ｏ_３、ＳｉＯ_２、ＳｉＯ_２−Ａｌ_２Ｏ_３、Ｃｒ_２Ｏ_３−ＭｇＯ、ＭｇＯ−ＣａＯ、ＭｇＯ−Ｃ、ＭｇＯ−Ａｌ_２Ｏ_３（スピネル）、ＳｉＣ、ＴｉＯ_２、Ｋ_２Ｏ、Ｎａ_２Ｏ、ＢａＯ、ＰｂＯ、Ｂ_２Ｏ_３、ＳｒＴｉＯ_３（チタン酸ストロンチウム）、ＢｅＡｌ_２Ｏ_４、Ｙ_３Ａｌ_５Ｏ_１２、ＺｒＯ_２−Ｙ_２Ｏ_３（立方晶ジルコニア）、３ＢｅＯ−Ａｌ_２Ｏ_３−６ＳｉＯ_２（合成エメラルド）、Ｃ（合成ダイヤモンド）、Ｓｉ_２Ｏ−ｎＨ_２Ｏ、窒化珪素、イットリウム安定化ジルコニア、ジルコニア強化アルミナ等が好ましい。分散時におけるビーズや分散機との摩擦による不純物生成が少ない等の理由から、イットリウム安定化ジルコニア、ジルコニア強化アルミナ（これらジルコニアを含有するセラミックスを、以下ジルコニアと略す）が特に好ましく用いられる。
【０１８６】
本発明の脂肪族カルボン酸銀塩粒子を分散する際に用いられる装置類において、該脂肪族カルボン酸銀塩粒子が接触する部材の材質としてジルコニア、アルミナ、窒化珪素、窒化硼素などのセラミックス類又はダイヤモンドを用いることが好ましく、中でもジルコニアを用いることが好ましい。
【０１８７】
上記分散を行う際、バインダー濃度は脂肪族カルボン酸銀質量の０．１〜１０％添加することが好ましく、予備分散から本分散を通して液温が４５℃を上回らないことが好ましい。又、本分散の好ましい運転条件としては、例えば高圧ホモジナイザを分散手段として用いる場合には、２９．４２〜９８．０６ＭＰａ、運転回数は２回以上が好ましい運転条件として挙げられる。又、メディア分散機を分散手段として用いる場合には、周速が６〜１３ｍ／秒が好ましい条件として挙げられる。
【０１８８】
脂肪族カルボン酸銀塩粒子に対する結晶成長抑制剤ないし分散剤として機能する化合物とは、脂肪族カルボン酸銀塩粒子の製造工程において、当該化合物を共存させた条件下で脂肪族カルボン酸銀を製造した時に、共存させない条件下で製造した時より小粒径化や単分散化する機能、効果を有する化合物を言う。具体例として、炭素数が１０以下の１価アルコール類、好ましくは第２級アルコール、第３級アルコール、エチレングリコール、プロピレングリコールなどのグリコール類、ポリエチレングリコール等のポリエーテル類、グリセリンが挙げられる。好ましい添加量としては、脂肪族カルボン酸銀に対して１０〜２００質量％である。
【０１８９】
一方で、ｉ−ヘプタン酸、ｉ−デカン酸、ｉ−トリデカン酸、ｉ−ミリスチン酸、ｉ−パルミチン酸、ｉ−ステアリン酸、ｉ−アラキジン酸、ｉ−ベヘン酸、ｉ−ヘキサコ酸など、それぞれ異性体を含む分岐脂肪族カルボン酸も好ましい。この場合、好ましい側鎖として、炭素数４以下のアルキル基又はアルケニル基が挙げられる。又、パルミトレイン酸、オレイン酸、リノール酸、リノレン酸、モロクチン酸、エイコセン酸、アラキドン酸、エイコサペンタエン酸、エルカ酸、ドコサペンタエン酸、ドコサヘキサエン酸、セラコレン酸などの脂肪族不飽和カルボン酸が挙げられる。好ましい添加量は、脂肪族カルボン酸銀の０．５〜１０モル％である。
【０１９０】
グルコシド、ガラクトシド、フルクトシド等の配糖体類、トレハロース、スクロース等のトレハロース型２糖類、グリコーゲン、デキストリン、デキストラン、アルギン酸等の多糖類、メチルセロソルブ、エチルセロソルブ等のセロソルブ類、ソルビタン、ソルビット、酢酸エチル、酢酸メチル、ジメチルホルムアミド等の水溶性有機溶媒、ポリビニルアルコール、ポリアクリル酸、アクリル酸共重合体、マレイン酸共重合体、カルボキシメチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロース、ポリビニルピロリドン、ゼラチン等の水溶性ポリマー類も好ましい化合物として挙げられる。これらの好ましい添加量としては脂肪族カルボン酸銀に対して０．１〜２０質量％である。
【０１９１】
炭素数が１０以下のアルコール、好ましくは、第２級又は第３級アルコールは、仕込み工程での脂肪族カルボン酸ナトリウムの溶解度を上げることにより減粘し、撹拌効率を上げることで単分散かつ小粒径化する。分岐脂肪族カルボン酸及び脂肪族不飽和カルボン酸は、脂肪族カルボン酸銀が結晶化する際にメイン成分である直鎖脂肪族カルボン酸銀よりも立体障害性が高く、結晶格子の乱れが大きくなるため大きな結晶は生成せず、結果的に小粒径化する。
【０１９２】
前述のように、従来のハロゲン化銀写真感光材料と比較して、銀塩光熱写真材料の構成上の最大の相違点は、後者の材料中には、現像処理の前後を問わず、カブリやプリントアウト銀（焼出し銀）の発生の原因となり得る感光性ハロゲン化銀、有機銀塩及び還元剤が多量含有されていることである。このため、銀塩光熱写真材料には、現像前ばかりでなく、現像後の保存安定性を維持するために、高度のカブリ防止及び画像安定化技術が必須であるが、従来はカブリ核の成長及び現像を抑制する芳香族性複素環化合物の他に、カブリ核を酸化消滅する機能を有する酢酸水銀のような水銀化合物が、非常に有効な保存安定化剤として使用されていたが、この水銀化合物の使用は安全性、環境保全性の点で問題であった。
【０１９３】
（調色剤）
銀塩光熱写真材料には調色剤を用いるのが望ましい。好適な調色剤の例は、Ｒｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ（ＲＤ）１７０２９号、米国特許４，１２３，２８２号、同３，９９４，７３２号、同３，８４６，１３６号及び同４，０２１，２４９号に開示されており、例えば、以下のものがある。
【０１９４】
イミド類（スクシンイミド、フタルイミド、ナフタールイミド、Ｎ−ヒドロキシ−１，８−ナフタールイミド等）；メルカプタン類（３−メルカプト−１，２，４−トリアゾール等）；フタラジノン誘導体又はこれらの誘導体の金属塩（フタラジノン、４−（１−ナフチル）フタラジノン、６−クロロフタラジノン、５，７−ジメチルオキシフタラジノン、２，３−ジヒドロ−１，４−フタラジンジオン等）；フタラジンとフタル酸類（フタル酸、４−メチルフタル酸、４−ニトロフタル酸、テトラクロロフタル酸等）の組合せ；フタラジンとマレイン酸無水物、及びフタル酸、２，３−ナフタレンジカルボン酸又はｏ−フェニレン酸誘導体及びその無水物（フタル酸、４−メチルフタル酸、４−ニトロフタル酸、テトラクロロフタル酸無水物等）から選択される少なくとも一つの化合物との組合せ等が挙げられる。特に好ましい色調剤としては、フタラジノン又はフタラジンとフタル酸類、フタル酸無水物類の組合せである。
【０１９５】
本発明では特に、フタル酸、４−メチルフタル酸、４−ニトロフタル酸、テトラクロロフタル酸無水物、安息香酸、４−メチル安息香酸、４−ニトロ安息香酸及びペンタクロロ安息香酸などのようにカルボン酸を含有する化合物を、画像形成層に隣接する非画像形成層に含有することが好ましい。更に好ましくは、画像形成層に対して支持体と反対側の非画像形成層に含有することである。
【０１９６】
非画像形成層に含有される本発明のカルボン酸基を含有する化合物の添加量は、好ましくは銀１モル当たり０．００５〜０．２０モルであり、更に好ましくは０．０１〜０．１０モルである。
【０１９７】
尚、従来医療診断用の出力画像の色調に関しては、冷調の画像調子の方が、レントゲン写真の判読者にとってより的確な記録画像の診断観察結果が得易いと言われている。ここで、冷調な画像調子とは、純黒調もしくは黒画像が青味を帯びた青黒調であり、温調な画像調子とは、黒画像が褐色味を帯びた温黒調であることを言う。
【０１９８】
色調に関しての用語「より冷調」及び「より温調」は、最低濃度Ｄｍｉｎ及び光学濃度Ｄ＝１．０における色相角ｈａｂにより求められる。色相角ｈａｂは国際照明委員会（ＣＩＥ）が１９７６年に推奨した、知覚的にほぼ均等な歩度を持つ色空間であるＬ^＊ａ^＊ｂ^＊色空間の色座標ａ^＊、ｂ^＊を用いて、次式によって求める。
【０１９９】
ｈａｂ＝ｔａｎ^−１（ｂ^＊／ａ^＊）
好ましいｈａｂの範囲は１８０°＜ｈａｂ＜２７０°であり、更に好ましくは２００°＜ｈａｂ＜２７０°、最も好ましくは２２０°＜ｈａｂ＜２６０°である。
【０２００】
（カブリ防止及び画像安定化剤）
銀塩光熱写真材料においては、還元剤として、後述するように主にビスフェノール類の還元剤が用いられているので、これらの水素を引き抜くことができる活性種を発生することにより還元剤を不活性化できる化合物が含有されていることが好ましい。好適には無色の光酸化性物質として、露光時にフリーラジカルを反応活性種として生成可能な化合物である。
【０２０１】
従って、これらの機能を有する化合物であれば如何なる化合物でもよいが、複数の原子から成る有機フリーラジカルが好ましい。かかる機能を有し、かつ銀塩光熱写真材料に格別の弊害を生じることのない化合物であれば、如何なる構造を持った化合物でもよい。又、これらのフリーラジカルを発生する化合物としては、発生するフリーラジカルに、還元剤と反応し不活性化するに充分な時間接触できる位の安定性を持たせるために、炭素環式又は複素環式の芳香族基を有するものが好ましい。
【０２０２】
これらの化合物の代表的なものとして以下に挙げるビイミダゾリル化合物、ヨードニウム化合物を挙げることができる。例えばビイミダゾリル化合物は、米国特許３，７３４，７３３号及び英国特許１，２７１，１７７号に記載される製造方法及びそれに準じた方法により製造することができる。好ましい具体例としては、例えば特開２０００−３２１７１１号に記載される化合物例が挙げられる。
【０２０３】
同様に、好適な化合物としてヨードニウム化合物を挙げることができる。ヨードニウム化合物は、Ｏｒｇ．Ｓｙｎ．，１９６１及びＦｉｅｓｅｒ著：Ａｄｖａｎｃｅｄ Ｏｒｇａｎｉｃ Ｃｈｅｍｉｓｔｒｙ（Ｒｅｉｎｈｏｌｄ，Ｎ．Ｙ．，１９６１）に記載される製造方法及びそれに準じた方法により合成できる。好ましい具体例としては、例えば特開２０００−３２１７１１号に記載される化合物例が挙げられる。
【０２０４】
これらの化合物の添加量は、１０^−３〜１０^−１モル／ｍ^２、好ましくは５×１０^−３〜５×１０^−２モル／ｍ^２である。尚、該化合物は、本発明の感光材料の如何なる構成層中にも含有させることができるが、還元剤の近傍に含有させることが好ましい。
【０２０５】
又、還元剤を不活性化し、還元剤が脂肪族カルボン酸銀塩を銀に還元できないようにする化合物としては、反応活性種がハロゲン原子でないものが好ましいが、ハロゲン原子を活性種として放出する化合物も、ハロゲン原子でない活性種を放出する化合物と併用することにより、使用することができる。ハロゲン原子を活性種として放出できる化合物も多くのものが知られており、併用により良好な効果が得られる。
【０２０６】
これらの活性ハロゲン原子を生成する化合物の具体例としては、特開２００１−２４９４２８号記載の４−１〜４−６４を挙げることができる。
【０２０７】
これらの化合物の添加量は、実質的にハロゲン化銀の生成によるプリントアウト銀の増加が問題にならない範囲が好ましく、前記活性ハロゲンラジカルを生成しない化合物に対する比率で最大１５０％以下、更に好ましくは１００％以下であることが望ましい。
【０２０８】
尚、上記化合物の他に、銀塩光熱写真材料中には、従来カブリ防止剤として知られている化合物が含まれてもよいが、上記化合物と同様な反応活性種を生成することができる化合物であっても、カブリ防止機構が異なる化合物であってもよい。例えば米国特許３，５８９，９０３号、同４，５４６，０７５号、同４，４５２，８８５号、特開昭５９−５７２３４号、米国特許３，８７４，９４６号、同４，７５６，９９９号、特開平９−２８８３２８号、同９−９０５５０号に記載される化合物が挙げられる。更に、その他のカブリ防止剤としては、米国特許５，０２８，５２３号及び欧州特許６００，５８７号、同６０５，９８１号、同６３１，１７６号に開示されている化合物が挙げられる。
【０２０９】
本発明の効果を損なわない範囲で、下記一般式（Ｂ）で表されるチオスルフォン酸化合物を併用することが好ましい。
【０２１０】
一般式（Ｂ） Ｒ−ＳＯ_２Ｓ−Ｍ
式中、Ｒは同じでも異なってもよく、脂肪族基、芳香族基又は複素環基を表し、Ｍは陽イオンを表す。
【０２１１】
Ｒが脂肪族基の場合、好ましくは炭素数が１〜２２のアルキル基、炭素数が２〜２２のアルケニル基、アルキニル基であり、これらは、置換基を有してもよい。アルキル基としては、例えばメチル、エチル、プロピル、ブチル、ペンチル、ヘキシル、オクチル、２−エチルヘキシル、デシル、ドデシル、ヘキサデシル、オクタデシル、シクロヘキシル、ｉ−プロピル、ｔ−ブチル等が挙げられる。
【０２１２】
アニケニル基としては、例えばアリル、ブテニルが挙げられる。
アルキニル基としては、例えばプロパルギル、ブチニルが挙げられる。
【０２１３】
Ｒが芳香族基の場合、好ましくは炭素数が６〜２０のもので、例えばフェニル、ナフチルが挙げられる。これらは置換されてもよい。
【０２１４】
Ｒが複素環基の場合、窒素、酸素、硫黄、セレン、テルルから選ばれる元素を少なくとも一つ有する３〜１５員環のものが好ましく、例えばピロリジニル、ピペリジニル、ピリジル、テトラヒドロフラニル、チエニル、オキサゾリル、チアゾリル、イミダゾリル、ベンゾチアゾリル、ベンズオキサゾリル、ベンズイミダゾリル、セレナゾリル、ベンゾセレナゾリル、テルラゾリル、トリアゾリル、ベンゾトリアゾリル、オキサジアゾリル、チアヂアゾリル等が挙げられる。
【０２１５】
Ｒの置換基としては、例えばアルキル基（メチル、エチル、ヘキシル等）、アルコキシ基（メトキシ、エトキシ、オクチル等）、アリール基（フェニル、ナフチル、トリル等）、ヒドロキシル基、ハロゲン原子（弗素、塩素、臭素、沃素）、アリールオキシ基（フェノキシ等）、アルキルチオ基（メチルチオ、ブチルチオ等）、アリールチオ基（フェニルチオ等）、アシル基（アセチル、プロピオニル、ブチリル、バレリル等）、スルホニル基（メチルスルホニル、フェニルスルホニル等）、アシルアミノ基（アセチルアミノ、ベンズアミノ等）、スルホニルアミノ基（メタンスルホニルアミノ、ベンゼンスルホニルアミノ等）、アシロキシ基（アセトキシ、ベンゾキシ等）、カルボキシル基、シアノ基、スルホ基、アミノ基が挙げられる。
【０２１６】
Ｍとして好ましくは、金属イオン又は有機カチオンである。金属イオンとしては、リチウムイオン、ナトリウムイオン、カリウムイオンが挙げられる。有機カチオンとしては、例えばアンモニウムイオン（アニモニウム、テトラメチルアンモニウム、テトラブチルアンモニウム等）、ホスホニウムイオン（テトラフェニルホスホニウム等）、グアニジル基が挙げられる。
【０２１７】
一般式（Ｂ）で表される化合物の乳剤への添加時期は、銀塩の粒子形成時、化学熟成前又は後、塗布直前のどの工程でもできる。好ましい添加時期は化学増感又は分光増感後から塗布直前である。好ましい添加量は銀１モル当たり１×１０^−５〜１モル、更に好ましくは１×１０^−３〜１×０．１モルである。
【０２１８】
（化学増感）
例えば特開２００１−２４９４２６号、同２００１−２４９４２８号に記載される方法等により、硫黄、セレン、テルルなどのカルコゲンを放出する化合物や金イオン等の貴金属イオンを放出する貴金属化合物の利用により、化学増感中心（化学増感核）を形成付与できる。特に、カルコゲン原子を含有する有機増感剤により化学増感されるのが好ましい。
【０２１９】
カルコゲン原子を含有する有機増感剤は、ハロゲン化銀へ吸着可能な基と不安定カルコゲン原子部位を有する化合物であることが好ましい。これらの有機増感剤としては、特開昭６０−１５００４６号、特開平４−１０９２４０号、同１１−２１８８７４号等に開示される種々の構造を有する有機増感剤を用いることができるが、それらの内、カルコゲン原子が炭素原子又は燐原子と二重結合で結ばれている構造を有する化合物の少なくとも１種であることが好ましい。
【０２２０】
有機増感剤としてのカルコゲン化合物の使用量は、使用するカルコゲン化合物、ハロゲン化銀粒子、化学増感を施す際の反応環境などにより変わるが、ハロゲン化銀１モル当たり１０^−８〜１０^−２モルが好ましく、より好ましくは１０^−７〜１０^−３モルを用いる。化学増感環境としては特に制限はないが、感光性ハロゲン化銀粒子上のカルコゲン化銀又は銀核を消滅あるいは、それらの大きさを減少させ得る化合物の存在下において、又、特に銀核を酸化し得る酸化剤の共存下において、カルコゲン原子を含有する有機増感剤を用いて増感を施すことが好ましく、該増感条件として、ｐＡｇは６〜１１が好ましく、より好ましくは７〜１０であり、ｐＨは４〜１０が好ましく、より好ましくは５〜８、又、温度は３０℃以下で増感を施すことが好ましい。
【０２２１】
従って、本発明の銀塩光熱写真材料においては、感光性ハロゲン化銀が、該粒子上の銀核を酸化し得る酸化剤の共存下において、カルコゲン原子を含有する有機増感剤を用いて、温度３０℃以下において化学増感を施され、かつ脂肪族カルボン酸銀塩と混合して分散され、脱水及び乾燥された感光性乳剤を用いることが好ましい。
【０２２２】
又、これらの有機増感剤を用いた化学増感は、分光増感色素又はハロゲン化銀粒子に対して、吸着性を有するヘテロ原子含有化合物の存在下で行われることが好ましい。ハロゲン化銀に吸着性を有する化合物の存在下で化学増感を行うことで、化学増感中心核の分散化を防ぐことができ、高感度、低カブリを達成できる。分光増感色素については後述するが、ハロゲン化銀に吸着性を有するヘテロ原子含有化合物とは、特開平３−２４５３７号に記載される含窒素複素環化合物が好ましい例として挙げられる。含窒素複素環化合物において、複素環としてはピラゾール環、ピリミジン環、１，２，４−トリアゾール環、１，２，３−トリアゾール環、１，３，４−チアジアゾール環、１，２，３−チアジアゾール環、１，２，４−チアジアゾール環、１，２，５−チアジアゾール環、１，２，３，４−テトラゾール環、ピリダジン環、１，２，３−トリアジン環、これらの環が２〜３個結合した環、例えばトリアゾロトリアゾール環、ジアザインデン環、トリアザインデン環、ペンタアザインデン環などを挙げることができる。単環の複素環と芳香族環の縮合した複素環、例えばフタラジン環、ベンズイミダゾール環、インダゾール環、ベンズチアゾール環なども適用できる。
【０２２３】
これらの中で好ましいのはアザインデン環であり、かつ置換基としてヒドロキシル基を有するアザインデン化合物、例えばヒドロキシトリアザインデン、ヒドロキシテトラザインデン、ヒドロキシペンタザインデン化合物等が更に好ましい。複素環にはヒドロキシル基以外の置換基を有してもよい。置換基としては、例えば（置換）アルキル基、アルキルチオ基、アミノ基、ヒドロキシアミノ基、アルキルアミノ基、ジアルキルアミノ基、アリールアミノ基、カルボキシル基、アルコキシカルボニル基、ハロゲン原子、シアノ基などが挙げられる。
【０２２４】
これ含複素環化合物の添加量は、ハロゲン化銀粒子の大きさや組成その他の条件等に応じて広い範囲に亘って変化するが、大凡、ハロゲン化銀１モル当たりの量で１０^−６〜１．０モルの範囲であり、好ましくは１０^−４〜１０^−１モルの範囲である。
【０２２５】
感光性ハロゲン化銀には、金イオン等の貴金属イオンを放出する化合物を利用して貴金属増感を施すことができる。例えば金増感剤として、塩化金酸塩や有機金化合物が利用できる。
【０２２６】
又、上記の増感法の他、還元増感法等も用いることができ、還元増感の貝体的な化合物としては、アスコルビン酸、二酸化チオ尿素、塩化第１錫、ヒドラジン誘導体、ボラン化合物、シラン化合物、ポリアミン化合物等を用いることができる。又、乳剤のｐＨを７以上又はｐＡｇを８．３以下に保持して熟成することにより還元増感することができる。
【０２２７】
化学増感を施されるハロゲン化銀は、有機銀塩の存在下で形成されたものでも、有機銀塩の存在しない条件下で形成されたものでも、又、両者が混合された条件下で形成されたものでもよい。
【０２２８】
（分光増感）
感光性ハロゲン化銀粒子には分光増感色素を吸着させ、分光増感を施すことが好ましい。分光増感色素としては、シアニン色素、メロシアニン色素、コンプレックスシアニン色素、コンプレックスメロシアニン色素、ホロポーラーシアニン色素、スチリル色素、ヘミシアニン色素、オキソノール色素、ヘミオキソノール色素等を用いることができる。例えば特開昭６３−１５９８４１号、同６０−１４０３３５号、同６３−２３１４３７号、同６３−２５９６５１号、同６３−３０４２４２号、同６３−１５２４５号、米国特許４，６３９，４１４号、同４，７４０，４５５号、同４，７４１，９６６号、同４，７５１，１７５号、同４，８３５，０９６号に記載された増感色素が使用できる。有用な増感色素は、例えばＲＤ１７６４３，２３頁，ＩＶ−Ａ項（１９７８年１２月）、同１８４３１，４３７頁，Ｘ項（１９７８年８月）に記載もしくは引用された文献に記載されている。特に、各種レーザーイメージャーやスキャナーの光源の分光特性に適した分光感度を有する増感色素を用いるのが好ましい。例えば特開平９−３４０７８号、同９−５４４０９号、同９−８０６７９号記載の化合物が好ましい。
【０２２９】
有用なシアニン色素は、例えばチアゾリン核、オキサゾリン核、ピロリン核、ピリジン核、オキサゾール核、チアゾール核、セレナゾール核及びイミダゾール核などの塩基性核を有するシアニン色素である。有用なメロシアニン染料で好ましいものは、上記の塩基性核に加えて、チオヒダントイン核、ローダニン核、オキサゾリジンジオン核、チアゾリンジオン核、バルビツール酸核、チアゾリノン核、マロノニトリル核及びピラゾロン核などの酸性核も含む。
【０２３０】
本発明においては、特に赤外に分光感度を有する増感色素を用いることが好ましい。好ましく用いられる赤外分光増感色素としては、例えば米国特許４，５３６，４７３号、同４，５１５，８８８号、同４，９５９，２９４号等に開示される赤外分光増感色素が挙げられる。本発明に用いられる赤外分光増感色素については、ベンズアゾール環のベンゼン環上にスルフィニル基が置換されていることを特徴とした長鎖のポリメチン色素が特に好ましい。
【０２３１】
上記の赤外増感色素は、例えばエフ・エム・ハーマー著：Ｔｈｅ Ｃｈｅｍｉｓｔｒｙ ｏｆ Ｈｅｔｅｒｏｃｙｃｌｉｃ Ｃｏｍｐｏｕｎｄｓ第１８巻，Ｔｈｅ Ｃｙａｎｉｎｅ Ｄｙｅｓ ａｎｄ Ｒｅｌａｔｅｄ Ｃｏｍｐｏｕｎｄｓ（Ａ．Ｗｅｉｓｓｂｅｒｇｅｒ ｅｄ．Ｉｎｔｅｒｓｃｉｅｎｃｅ社刊，Ｎｅｗ Ｙｏｒｋ，１９６４年）に記載の方法により容易に合成することができる。
【０２３２】
これらの赤外増感色素の添加時期は、ハロゲン化銀調製後から脂肪族カルボン酸銀塩と混合するまでが好ましい。更に、微粒子状に分散した所謂固体分散状態でハロゲン化銀粒子を含有する感光性乳剤に添加することが好ましい。又、前記のハロゲン化銀粒子に対し吸着性を有するヘテロ原子含有化合物と同様に、化学増感に先立ってハロゲン化銀粒子に添加し吸着させた後、化学増感を施すこともでき、これにより化学増感中心核の分散化を防ぐことができ高感度、低カブリを達成できる。
【０２３３】
上記の分光増感色素は単独に用いてもよいが、それらの組合せを用いてもよく、増感色素の組合せは特に強色増感の目的でしばしば用いられる。
【０２３４】
（強色増感）
銀塩光電写真材料に用いられる感光性ハロゲン化銀、脂肪族カルボン酸銀塩を含有する乳剤は、増感色素と共にそれ自身分光増感作用を持たない色素、又は可視光を実質的に吸収しない物質であるが、強色増感効果を発現する物質を乳剤中に含ませ、これによりハロゲン化銀粒子が強色増感されてもよい。
【０２３５】
有用な増感色素、強色増感を示す色素の組合せ及び強色増感を示す物質は、ＲＤ１７６４３，２３頁ＩＶ−Ｊ項（１９７８年１２月発行）、特公平９−２５５００号、特開昭５９−１９０３２号、同５９−１９２２４２号、特開平５−３４１４３２号等に記載されるが、強色増感剤としては、下記で表される複素芳香族メルカプト化合物又はメルカプト誘導体化合物が好ましい。
【０２３６】
Ａｒ−ＳＭ
式中、Ｍは水素原子又はアルカリ金属原子であり、Ａｒは１個以上の窒素、硫黄、酸素、セレニウム又はテルリウム原子を有する芳香環又は縮合芳香環である。好ましい複素芳香環は、ベンズイミダゾール、ナフトイミダゾール、ベンゾチアゾール、ナフトチアゾール、ベンゾオキサゾール、ナフトオキサゾール、ベンゾセレナゾール、ベンゾテルラゾール、イミダゾール、オキサゾール、ピラゾール、トリアゾール、トリアジン、ピリミジン、ピリダジン、ピラジン、ピリジン、プリン、キノリン又はキナゾリンである。しかしながら、他の複素芳香環を含んでもよい。
【０２３７】
尚、脂肪族カルボン酸銀塩及び／又はハロゲン化銀粒子乳剤の分散物中に含有させた時に、実質的に上記のメルカプト化合物を生成するメルカプト誘導体化合物も含まれる。特に、下記に表されるメルカプト誘導体化合物が好ましい例として挙げられる。
【０２３８】
Ａｒ−Ｓ−Ｓ−Ａｒ
式中のＡｒは、上記で表されたメルカプト化合物の場合と同義である。
【０２３９】
上記の複素芳香環は、例えばハロゲン原子（塩素、臭素、沃素等）、ヒドロキシル基、アミノ基、カルボキシル基、アルキル基（１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）及びアルコキシ基（１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）から選ばれる置換基を有してもよい。
【０２４０】
上記の強色増感剤の他に、特開２００１−２１５６５２号の段落「００１２」に記載される一般式（１）で表される化合物と大環状化合物を強色増感剤として使用できる。
【０２４１】
上記大環状化合物は、ヘテロ原子として窒素原子、酸素原子、硫黄原子、セレン原子の少なくとも１種を含む９員環以上の大環状化合物が好ましい。更に１２〜２４員環が好ましく、更に好ましいのは１５〜２１員環である。代表的な化合物としては、クラウンエーテルとして知られている化合物でＰｅｄｅｒｓｏｎが１９６７年に合成し、その特異な質を報告以来、数多く合成されているものである。
【０２４２】
これらの化合物は、Ｃ．Ｊ．Ｐｅｄｅｒｓｏｎ：Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．，８６（２４９５），７０１７〜７０３６（１９６７）、Ｇ．Ｗ．Ｇｏｋｅｌ，Ｓ．Ｈ，Ｋｏｒｚｅｎｉｏｗｓｋｉ：Ｍａｃｒｏｃｙｃｌｉｃ ｐｏｌｙｅｔｈｒ ｓｙｎｔｈｅｓｉｓ，Ｓｐｒｉｎｇｅｒ−Ｖｅｒｇａｌ，（１９８２）、小田、庄野、田伏編；クラウンエーテルの化学，化学同人（１９７８）、田伏編：ホスト−ゲスト，共立出版（１９７９）、佐々木、古賀：有機合成化学４５巻（６），５７１〜５８２頁（１９８７）等に詳細に書かれている。
【０２４３】
本発明に用いることが出来る強色増感剤は、有機銀塩及びハロゲン化銀粒子を含む乳剤層中に銀１モル当たり０．００１〜１．０モルの範囲で用いるのが好ましい。特に好ましくは０．０１〜０．５モルの範囲である。
【０２４４】
（バインダー）
銀塩光熱写真材料に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、アラビアゴム、ポリビニルアルコール（ＰＶＡ）、ヒドロキシエチルセルロース、セルロースアセテート、セルロースアセテートブチレート、ポリビニルピロリドン（ＰＶＰ）、カゼイン、澱粉、ポリアクリル酸、ポリメチルメタクリル酸、ポリ塩化ビニル、ポリメタクリル酸、コポリ（スチレン−無水マレイン酸）、コポリ（スチレン−アクリロニトリル）、コポリ（スチレン−ブタジエン）、ポリビニルアセタール類（ポリビニルホルマール及びポリビニルブチラール等）、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、ポリエポキシド類、ポリカーボネート類、ポリビニルアセテート、セルロースエステル類、ポリアミド類が挙げられる。これらは親水性でも非親水性でもよい。
【０２４５】
本発明の銀塩光熱写真材料の画像形成層に好ましいバインダーはポリビニルアセタール類であり、特に好ましいバインダーはポリビニルブチラールである。詳しくは後述する。又、上塗り層や下塗り層、特に保護層やバックコート層等の非画像形成層に対しては、より軟化温度の高いポリマーであるセルロースエステル類、特にトリアセチルセルロース（ＴＡＣ）、セルロースアセテートブチレート等のポリマーが好ましい。尚、必要に応じて、上記のバインダーは２種以上を組み合わせて用い得る。
【０２４６】
このようなバインダーは、バインダーとして機能するのに効果的な範囲で用いられる。効果的な範囲は当業者が容易に決定し得る。例えば、画像形成層において少なくとも脂肪族カルボン酸銀塩を保持する場合の指標としては、バインダーと脂肪族カルボン酸銀塩との割合（質量比）は１５：１〜１：２、特に８：１〜１：１の範囲が好ましい。即ち、画像形成層のバインダー量が１．５〜６ｇ／ｍ^２であることが好ましい。更に好ましくは１．７〜５ｇ／ｍ^２である。１．５ｇ／ｍ^２未満では未露光部の濃度が大幅に上昇し、使用に耐えない場合がある。
【０２４７】
本発明では、１００℃以上の温度で現像処理した後の熱転移点温度が４６〜２００℃であることが好ましい。本発明で言う熱転移点温度とは、ＶＩＣＡＴ軟化点又は環球法で示した値であり、示差走査熱量計（ＤＳＣ）、例えばＥＸＳＴＡＲ ６０００（セイコー電子社製）、ＤＳＣ２２０Ｃ（セイコー電子工業社製）、ＤＳＣ−７（パーキンエルマー社製）等を用いて、熱現像済みの画像形成層を単離して測定した際の吸熱ピークを指す。一般的に、高分子化合物はガラス転移点（Ｔｇ）を有しているが、銀塩光熱写真材料においては、画像形成層に用いているバインダー樹脂のＴｇ値よりも低いところに、大きな吸熱ピークが出現する。この熱転移点温度に着目し鋭意検討を行った結果、この熱転移点温度を４６〜２００℃にすることにより、形成された塗膜の堅牢性が増すのみならず、感度、最大濃度、画像保存性など写真性能が大幅に向上する。
【０２４８】
Ｔｇは、ブランドラップらによる「重合体ハンドブック」ＩＩＩ−１３９頁〜ＩＩＩ−１７９頁（１９６６年，ワイリー アンド サン社版）に記載の方法で求めたものであり、バインダーが共重合体樹脂である場合のＴｇは下記の式で求められる。
【０２４９】
Ｔｇ（共重合体）（℃）＝ｖ_１Ｔｇ_１＋ｖ_２Ｔｇ_２＋・・・＋ｖ_ｎＴｇ_ｎ
式中、ｖ_１、ｖ_２・・・ｖ_ｎは共重合体中の単量体の質量分率を表し、Ｔｇ_１、Ｔｇ_２・・・Ｔｇ_ｎは、共重合体中の各単量体から得られる単一重合体のＴｇ（℃）を表す。上式に従って計算されたＴｇの精度は±５℃である。
【０２５０】
銀塩光熱写真材料において、支持体上に脂肪族カルボン酸銀塩、感光性ハロゲン化銀粒子、還元剤等を含有する画像形成層に含有するバインダーとしては、従来公知の高分子化合物を用いることができる。Ｔｇが７０〜１０５℃、数平均分子量が１，０００〜１，０００，０００、好ましくは１０，０００〜５００，０００、重合度が約５０〜１，０００程度のものである。このような例としては、塩化ビニル、酢酸ビニル、ビニルアルコール、マレイン酸、アクリル酸、アクリル酸エステル、塩化ビニリデン、アクリロニトリル、メタクリル酸、メタクリル酸エステル、スチレン、ブタジエン、エチレン、ビニルブチラール、ビニルアセタール、ビニルエーテル等のエチレン性不飽和モノマーを構成単位として含む重合体又は共重合体より成る化合物、ポリウレタン樹脂、各種ゴム系樹脂がある。
【０２５１】
又、フェノール樹脂、エポキシ樹脂、ポリウレタン硬化型樹脂、尿素樹脂、メラミン樹脂、アルキド樹脂、ホルムアルデヒド樹脂、シリコーン樹脂、エポキシ−ポリアミド樹脂、ポリエステル樹脂等が挙げられる。これらの樹脂については、朝倉書店発行の「プラスチックハンドブック」に詳細な記載がある。
【０２５２】
これらの高分子化合物に特に制限はなく、誘導される重合体のＴｇが７０〜１０５℃の範囲にあれば、単独重合体でも共重合体でもよい。
【０２５３】
このようなエチレン性不飽和モノマーを構成単位として含む重合体又は共重合体としては、（メタ）アクリル酸アルキルエステル類、（メタ）アクリル酸アリールエステル類、シアノアクリル酸アルキルエステル類、シアノアクリル酸アリールエステル類などを挙げることができ、それらのアルキル基、アリール基は置換されてもよく、具体的にはメチル、エチル、プロピル、ｉ−プロピル、ブチル、ｉ−ブチル、ｓｅｃ−ブチル、ｔ−ブチル、アミル、ヘキシル、シクロヘキシル、ベンジル、クロロベンジル、オクチル、ステアリル、スルホプロピル、Ｎ−エチル−フェニルアミノエチル、２−（３−フェニルプロピルオキシ）エチル、ジメチルアミノフェノキシエチル、フルフリル、テトラヒドロフルフリル、フェニル、クレジル、ナフチル、２−ヒドロキシエチル、４−ヒドロキシブチル、トリエチレングリコール、ジプロピレングリコール、２−メトキシエチル、３−メトキシブチル、２−アセトキシエチル、２−アセトアセトキシエチル、２−エトキシエチル、２−ｉ−プロポキシエチル、２−ブトキシエチル、２−（２−メトキシエトキシ）エチル、２−（２−エトキシエトキシ）エチル、２−（２−ブトキシエトキシ）エチル、２−ジフェニルホスホリルエチル、ω−メトキシポリエチレングリコール（付加モル数ｎ＝６）、アリル、ジメチルアミノエチルメチルクロライド塩などを挙げることができる。
【０２５４】
その他、下記のモノマー等が使用できる。
ビニルエステル類：ビニルアセテート、ビニルプロピオネート、ビニルブチレート、ビニル−ｉ−ブチレート、ビニルカプロエート、ビニルクロロアセテート、ビニルメトキシアセテート、ビニルフェニルアセテート、安息香酸ビニル、サリチル酸ビニル等。
【０２５５】
Ｎ−置換アクリルアミド類、Ｎ−置換メタクリルアミド類及びアクリルアミド、メタクリルアミド：Ｎ−置換基としては、メチル、エチル、プロピル、ブチル、ｔｅｒｔ−ブチル、シクロヘキシル、ベンジル、ヒドロキシメチル、メトキシエチル、ジメチルアミノエチル、フェニル、ジメチル、ジエチル、β−シアノエチル、Ｎ−（２−アセトアセトキシエチル）、ジアセトン等。
【０２５６】
オレフィン類：ジシクロペンタジエン、エチレン、プロピレン、１−ブテン、１−ペンテン、塩化ビニル、塩化ビニリデン、イソプレン、クロロプレン、ブタジエン、２，３−ジメチルブタジエン等。
【０２５７】
スチレン類：メチルスチレン、ジメチルスチレン、トリメチルスチレン、エチルスチレン、ｉ−プロピルスチレン、ｔ−ブチルスチレン、クロロメチルスチレン、メトキシスチレン、アセトキシスチレン、クロろスチレン、ジクロロスチレン、ブロモスチレン、ビニル安息香酸メチルエステル等。
【０２５８】
ビニルエーテル類：メチルビニルエーテル、ブチルビニルエーテル、ヘキシルビニルエーテル、メトキシエチルビニルエーテル、ジメチルアミノエチルビニルエーテル等。
【０２５９】
Ｎ−置換マレイミド類：Ｎ−置換基として、メチル、エチル、プロピル、ブチル、ｔ−ブチル、シクロヘキシル、ベンジル、ドデシル、フェニル、２−メチルフェニル、２，６−ジエチルフェニル、２−クロルフェニルなどを有するもの等。
【０２６０】
その他：クロトン酸ブチル、クロトン酸ヘキシル、イタコン酸ジメチル、イタコン酸ジブチル、マレイン酸ジエチル、マレイン酸ジメチル、マレイン酸ジブチル、フマル酸ジエチル、フマル酸ジメチル、フマル酸ジブチル、メチルビニルケトン、フェニルビニルケトン、メトキシエチルビニルケトン、グリシジルアクリレート、グリシジルメタクリレート、Ｎ−ビニルオキサゾリドン、Ｎ−ビニルピロリドン、アクリロニトリル、メタアクリロニトリル、メチレンマロンニトリル、塩化ビニリデン等。
【０２６１】
これらの内、特に好ましい例としては、メタクリル酸アルキルエステル類、メタクリル酸アリールエステル類、スチレン類等が挙げられる。このような高分子化合物の中でも、アセタール基を持つ高分子化合物を用いることが好ましい。アセタール基を持つ高分子化合物では、生成する脂肪族カルボン酸との相溶性に優れるため膜の柔軟化を防ぐ効果が大きく好ましい。
【０２６２】
（架橋剤）
上記バインダーに対し架橋剤を用いることにより膜付きが良くなり、現像ムラが少なくなることは知られているが、保存時のカブリ抑制や、現像後のプリントアウト銀の生成を抑制する効果もある。
【０２６３】
本発明で用いられる架橋剤としては、従来ハロゲン化銀写真感光材料用として使用されている種々の架橋剤、例えば特開昭５０−９６２１６号に記載されるアルデヒド系、エポキシ系、エチレンイミン系、ビニルスルホン系、スルホン酸エステル系、アクリロイル系、カルボジイミド系、シラン系架橋剤を用い得るが、好ましいのはイソシアネート化合物、シラン化合物、エポキシ化合物又は酸無水物である。
【０２６４】
架橋剤は、画像形成層、表面保護層、中間層、アンチハレーション層、下引層等の支持体の画像形成層側の任意の層に添加でき、これらの層の１層又は２層以上に添加することができる。
【０２６５】
（マット剤）
銀塩光熱写真材料の表面層に（画像形成層側、又、支持体を挟み画像形成層の反対側に非画像形成層を設けた場合にも）、現像前の取扱いや熱現像後の画像の傷付き防止のためマット剤を含有することが好ましく、バインダーに対し質量比で０．１〜３０％含有することが好ましい。
【０２６６】
マット剤の材質は、有機物及び無機物の何れでもよい。無機物としては、スイス特許３３０，１５８号等に記載のシリカ、仏国特許１，２９６，９９５号等に記載のガラス粉、英国特許１，１７３，１８１号等に記載のアルカリ土類金属又はカドミウム、亜鉛等の炭酸塩等をマット剤として用いることができる。有機物としては、米国特許２，３２２，０３７号等に記載の澱粉、ベルギー特許６２５，４５１号や英国特許９８１，１９８号等に記載された澱粉誘導体、特公昭４４−３６４３号等に記載のポリビニルアルコール、スイス特許３３０，１５８号等に記載のポリスチレンあるいはポリメタアクリレート、米国特許３，０７９，２５７号等に記載のポリアクリロニトリル、米国特許３，０２２，１６９号等に記載されたポリカーボネートの様な有機マット剤を用いることができる。
【０２６７】
マット剤は、均粒径が０．５〜１０μｍであることが好ましく、更に好ましくは１．０〜８．０μｍである。又、粒子サイズ分布の変動係数としては５０％以下であることが好ましく、更に好ましくは４０％以下であり、特に好ましくは３０％以下となるマット剤である。
【０２６８】
ここで、粒子サイズ分布の変動係数（％）は、下記の式で表される値である。
粒子サイズ分布の変動係数＝（粒径の標準偏差／粒径の平均値）×１００
マット剤の添加方法は、予め塗布液中に分散させて塗布する方法でもよいし、塗布液を塗布した後、乾燥が終了する以前にマット剤を噴霧する方法を用いてもよい。又、複数の種類のマット剤を添加する場合は、両方の方法を併用してもよい。
【０２６９】
（支持体、補助層、その他）
銀塩光熱写真材料に用いる支持体の素材としては、各種高分子材料、ガラス、ウール布、コットン布、紙、金属（アルミニウム等）等が挙げられるが、情報記録材料としての取扱い上は、可撓性のあるシート又はロールに加工できるものが好適である。従って、本発明の銀塩光熱写真材料に用いる支持体としては、プラスチックフィルム（セルロースアセテートフィルム、ポリエステルフィルム、ポリエチレンテレフタレートフィルム、ポリエチレンナフタレートフィルム、ポリアミドフィルム、ポリイミドフィルム、セルローストリアセテートフィルム又はポリカーボネートフィルム等）が好ましく、２軸延伸したポリエチレンテレフタレートフィルムが特に好ましい。支持体の厚みとしては５０〜３００μｍ程度、好ましくは７０〜１８０μｍである。
【０２７０】
本発明の銀塩光熱写真材料は、支持体上に少なくとも１層の画像形成層を有している。支持体の上に画像形成層のみを形成してもよいが、画像形成層の上に少なくとも１層の非画像形成層を形成するのが好ましい。例えば、画像形成層の上には保護層が画像形成層を保護する目的で、又、支持体の反対の面には銀塩光熱写真材料間の、あるいは銀塩光熱写真材料−搬送ロール間における「くっ付き」を防止する為に、バックコート層が設けられるのが好ましい。
【０２７１】
これらの保護層やバックコート層に用いるバインダーとしては、画像形成層よりもＴｇが高く、擦傷や、変形の生じ難いポリマー、例えばセルロースアセテート、セルロースアセテートブチレート等のポリマーが選ばれる。尚、階調調整等のために、画像形成層を支持体の一方の側に２層以上又は支持体の両側に１層以上設置してもよい。
【０２７２】
銀塩光熱写真材料においては、画像形成層を透過する光の量又は波長分布を制御するために、画像形成層と同じ側又は反対の側にフィルター層を形成するか、画像形成層に染料又は顔料を含有させることが好ましい。
【０２７３】
用いられる染料としては、銀塩光熱写真材料の感色性に応じて種々の波長領域の光を吸収する公知の化合物が使用できる。例えば、銀塩光熱写真材料を赤外光による画像記録材料とする場合には、特開２００１−８３６５５号に開示されているようなチオピリリウム核を有するスクアリリウム染料及びピリリウム核を有するスクアリリウム染料、又スクアリリウム染料に類似したチオピリリウムクロコニウム染料又はピリリウムクロコニウム染料を使用することが好ましい。
【０２７４】
尚、スクアリリウム核を有する化合物とは、分子構造中に１−シクロブテン−２−ヒドロキシ−４−オンを有する化合物であり、クロコニウム核を有する化合物とは分子構造中に１−シクロペンテン−２−ヒドロキシ−４，５−ジオンを有する化合物である。ここで、ヒドロキシル基は解離していてもよい。以下、本発明では、これらの色素を便宜的に一括してスクアリリウム染料と呼ぶ。尚、染料としては、特開平８−２０１９５９号の化合物も好ましい。
【０２７５】
（銀塩光熱写真材料の塗布）
本発明の銀塩光熱写真材料は、上述した各構成層の素材を溶媒に溶解又は分散させた塗布液を作り、各塗布液を複数同時に重層塗布した後、加熱処理を行って形成することが好ましい。ここで「複数同時に重層塗布」とは、各構成層（画像形成層、保護層、バック層など）の塗布液を作製し、これを支持体へ塗布する際に各層個別に塗布・乾燥を繰り返すのではなく、同時に重層塗布を行い乾燥する工程も同時に行える状態で各構成層を形成し得ることを意味する。即ち、下層中の全溶剤の残存量が７０質量％以下となる前に、上層を設けることである。
【０２７６】
各構成層を複数同時に重層塗布する方法には特に制限はなく、例えばバーコーター法、カーテンコート法、浸漬法、エアーナイフ法、ホッパー塗布法、エクストリュージョン塗布法などの公知の方法を用いることができる。これらの内、より好ましくはエクストリュージョン塗布法と呼ばれる前計量タイプの塗布方式である。該エクストリュージョン塗布法は、スライド塗布方式のようにスライド面での揮発がないため、精密塗布、有機溶剤塗布に適している。この塗布方法は画像形成層を有する側について述べたが、バックコート層を設ける際、下引きと共に塗布する場合についても同様である。
【０２７７】
（露光方法）
本発明において、露光はレーザー走査露光により行うことが好ましいが、その露光方法には種々の方法が採用できる。例えば、第１の好ましい方法として、感光材料の露光面と走査レーザー光のなす角が実質的に垂直になることがないレーザー走査露光機を用いる方法が挙げられる。ここで、「実質的に垂直になることがない」とは、レーザー走査中に最も垂直に近い角度として、好ましくは５５〜８８°、より好ましくは６０〜８６°、更に好ましくは６５〜８４°、最も好ましくは７０〜８２°であることを言う。
【０２７８】
レーザー光が、銀塩光熱写真ドライイメージング材料に走査される時の写真材料露光面でのビームスポット直径は、好ましくは２００μｍ以下、より好ましくは１００μｍ以下である。これは、スポット径が小さい方がレーザー入射角度の垂直からの「ずらし角度」を減らせる点で好ましい。尚、ビームスポット直径の下限は１０μｍである。このようなレーザー走査露光を行うことにより、干渉縞様のムラの発生等のような反射光に因る画質劣化を減らすことが出来る。
【０２７９】
又、第２の方法として、縦マルチである走査レーザー光を発するレーザー走査露光機を用いて露光を行うことも好ましい。縦単一モードの走査レーザー光に比べて、干渉縞様のムラの発生等の画質劣化が減少する。
【０２８０】
縦マルチ化するには、合波による戻り光を利用する、高周波重畳を掛けるなどの方法がよい。尚、縦マルチとは露光波長が単一でないことを意味し、通常、露光波長の分布が５ｎｍ以上、好ましくは１０ｎｍ以上になるとよい。露光波長の分布の上限には特に制限はないが、通常、６０ｎｍ程度である。
【０２８１】
尚、上述の第１、第２の態様の画像記録方法において、走査露光に用いるレーザーとしては、一般によく知られている、ルビーレーザー、ＹＡＧレーザー、ガラスレーザー等の固体レーザー；Ｈｅ−Ｎｅレーザー、Ａｒイオンレーザー、Ｋｒイオンレーザー、ＣＯ_２レーザー、ＣＯレーザー、Ｈｅ−Ｃｄレーザー、Ｎ_２レーザー、エキシマーレーザー等の気体レーザー；ＩｎＧａＰレーザー、ＡｌＧａＡｓレーザー、ＧａＡｓＰレーザー、ＩｎＧａＡｓレーザー、ＩｎＡｓＰレーザー、ＣｄＳｎＰレーザー、ＧａＳｂレーザー等の半導体レーザー；化学レーザー、色素レーザー等を用途に併せて適時選択して使用できるが、これらの中でも、メンテナンスや光源の大きさの問題から、波長が６００〜１２００ｎｍの半導体レーザーを用いるのが好ましい。尚、レーザー・イメージャやレーザー・イメージセッタで使用されるレーザーにおいて、写真材料に走査される時の該材料露光面でのビームスポット径は、一般に短軸径として５〜７５μｍ、長軸径として５〜１００μｍの範囲であり、レーザー光走査速度は写真材料固有のレーザー発振波長における感度とレーザーパワーによって、銀塩光熱写真材料毎に最適な値に設定することができる。
【０２８２】
（熱現像方法）
銀塩光熱写真材料の現像条件は、使用する機器、装置、或いは手段に依存して変化するが、典型的には、適した高温において、像様に露光した写真材料を加熱することを伴う。露光後に得られた潜像は、中程度の高温（約１００〜２００℃）で十分な時間（一般には、約１秒〜約２分間）、写真材料を加熱することにより現像する。加熱温度が１００℃未満では短時間に十分な画像濃度が得られず、又、２００℃を超すとバインダーが溶融し、ローラーへの転写など、画像そのものだけでなく、搬送性や現像機等へも悪影響を及ぼす。
【０２８３】
加熱することで、脂肪族カルボン酸銀塩（酸化剤として機能する）と還元剤との間の酸化還元反応により銀画像を生成する。この反応過程は、外部からの水等の処理液の一切の供給なしに進行する。
【０２８４】
加熱する機器、装置、手段はホットプレート、アイロン、ホットローラー、炭素又は白色チタン等を用いた熱発生器として典型的な加熱手段で行ってよい。より好ましくは、保護層の設けられた銀塩光熱写真材料は、保護層を有する側の面を加熱手段と接触させ加熱処理するのが、均一な加熱を行う上で、又、熱効率、作業性の点などから好ましく、該面をヒートローラに接触させながら搬送し、加熱処理して現像することが好ましい。
【０２８５】
銀塩光熱写真材料の露光は、当該写真材料に付与した感色性に対し、適切な光源を用いることが望ましい。例えば、当該感光材料を赤外光に感じ得るものとした場合は、赤外光域ならば如何なる光源にも適用可能であるが、レーザーパワーがハイパワーである事や、感光材料を透明にできる等の点から、赤外半導体レーザー（７８０ｎｍ、８２０ｎｍ）が、より好ましく用いられる。
【０２８６】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明はこれらに限定されるものではない。尚、特に断りない限り、実施例中の「部」は「質量部」を、「％」は「質量％」を表す。
【０２８７】
実施例１
〈複合共重合体水分散液ＡＬＸ０１の合成〉
フルゾーン翼撹拌機、温度計、滴下ロート、窒素導入管、還流冷却器を備えた１０００ｍｌの四ツ口フラスコ（以下、反応釜）に純水１９０．０ｍｌを添加し、撹拌翼を回しながら３２ｇの共重合ポリエステル１を徐々に１０分間で添加した。この後、反応釜を内温が９５℃になるまで加熱し、９５℃を３時間保持した。滴下ロート内に、メチルメタクリレート４．８ｇ、ブチルアクリレート０．８ｇ、エチルアクリレート２．４ｇを秤り採り混合・攪拌した。９５℃で３時間加熱後、反応釜の内温を８０℃まで下げ、その途中で酸化錫系化合物１の水分散液を３４３ｇ添加した。その後、反応釜に窒素ガスを３０分間吹き込んだ。釜内温度が８０℃となった時点で、ペルオキソ二硫酸アンモニウム０．１８ｇを添加した。添加５分後、混合モノマーを滴下ロートより１０分間で滴下した。滴下ロートが空になったら、この中に純水６ｍｌを入れ管内のモノマーを送り出した。
【０２８８】
重合開始剤添加後から３時間、内温を８０℃に保持し反応を行った。この後、内温が３０℃以下になるまで冷水にて冷却し、本発明の複合共重合体水分散液ＡＬＸ０１を得た。
【０２８９】
表１に記載のビニル系単量体組成、酸化錫系化合物の種類、酸化錫／水分散性共重合ポリエステル／ビニル系単量体の比を変化させた以外は複合共重合体水分散液ＡＬＸ０１の合成と同様にして、本発明の複合共重合体水分散液ＡＬＸ０２〜ＡＬＸ１７及び比較の水分散液を合成した。
【０２９０】
【表１】

【０２９１】
実施例２
以下のように銀塩光熱写真材料試料を作製した。
【０２９２】
〈下引き済み支持体の作製〉
濃度０．１７０に青色着色したＰＥＴフィルムベース（厚み１７５μｍ）の片方の面に、０．５ｋＶ・Ａ・ｍｉｎ／ｍ^２のコロナ放電処理を施した後、その上に下記の画像形成層側下引塗布液Ａを用い、下引層ａを乾燥膜厚が０．２μｍになるように塗設した。更に、もう一方の面に、同様に０．５ｋＶ・Ａ・ｍｉｎ／ｍ^２のコロナ放電処理を施した後、その上に下記のバッキング層側下引塗布液Ｂを用い、下引層ｂを乾燥膜厚が０．１μｍとなるように塗設した。その後、複数のロール群から成るフィルム搬送装置を有する熱処理式オーブン中で、１３０℃にて１５分熱処理を行い、下引き済み支持体を作製した。
（画像形成層側下引塗布液Ａ）
ブチルアクリレート／ｔ−ブチルアクリレート／スチレン／２−ヒドロキシエチルアクリレート（３０／２０／２５／２５％比）の共重合体ラテックス液（固形分３０％）７４ｇ、界面活性剤（ＵＬ−１）０．１ｇ及びメチルセルロース０．５ｇを混合した。更に、シリカ粒子（サイロイド３５０：富士シリシア社製）１．３ｇを水１００ｇに添加し、超音波分散機（ＡＬＥＸ Ｃｏｒｐｏｒａｔｉｏｎ社製：Ｕｌｔｒａｓｏｎｉｃ Ｇｅｎｅｒａｔｏｒ，周波数２５ｋＨｚ，６００Ｗ）にて３０分間分散処理した分散液を加え、最後に水で１０００ｍｌに仕上げて下引塗布液Ａとした。
（バッキング層側下引塗布液Ｂ）
複合共重合体水分散液ＡＬＸ０１の５６ｇと界面活性剤（ＵＬ−１）の０．１ｇを混合し、水で１０００ｍｌに仕上げて下引塗布液Ｂとした。
【０２９３】
【化１２】

【０２９４】
（バッッキング層塗布液）
メチルエチルケトン（ＭＥＫ）８３０ｇを撹拌しながら、セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社製：ＣＡＢ３８１−２０）８４．２ｇ及びポリエステル樹脂（Ｂｏｓｔｉｃ社製：ＶｉｔｅｌＰＥ２２００Ｂ）４．５ｇを添加し溶解した。溶解液に０．３０ｇの赤外染料１を添加し、更にメタノール４３．２ｇに溶解した弗素系活性剤（旭硝子社製：サーフロンＫＨ４０）４．５ｇと弗素系活性剤（大日本インク社製：メガファッグＦ１２０Ｋ）２．３ｇを添加し、溶解するまで十分に撹拌した。最後に、ＭＥＫに１％濃度でディゾルバ型ホモジナイザにて分散したシリカ（Ｗ．Ｒ．Ｇｒａｃｅ社製：シロイド６４Ｘ６０００）７５ｇを添加、撹拌してバッキング層塗布液とした。
【０２９５】
【化１３】

【０２９６】
上記バッキング層塗布液を、前記下引き済み支持体１のバッキング層側下引き上に、乾燥膜厚が３．５μｍになるように押出しコーターにて塗布・乾燥を行った。乾燥温度１００℃、露点温度１０℃の乾燥風を用いて５分間かけて乾燥した。
【０２９７】
〈感光性ハロゲン化銀乳剤の調製〉
溶液（Ａ１）
フェニルカルバモイル化ゼラチン ８８．３ｇ
化合物（Ｋ）の１０％メタノール水溶液 １０ｍｌ
臭化カリウム ０．３２ｇ
水で５４２９ｍｌに仕上げる
溶液（Ｂ１）
０．６７ｍｏｌ／Ｌ硝酸銀水溶液 ２６３５ｍｌ
溶液（Ｃ１）
臭化カリウム ５１．５５ｇ
沃化カリウム １．４７ｇ
水で６６０ｍｌに仕上げる
溶液（Ｄ１）
臭化カリウム １５４．９ｇ
沃化カリウム ４．４１ｇ
塩化オスミウム（１％溶液） ０．９３ｍｌ
水で１９８２ｍｌに仕上げる。
溶液（Ｅ１）
０．４ｍｏｌ／Ｌ臭化カリウム水溶液 下記銀電位制御量
溶液（Ｆ１）
水酸化カリウム ０．７１ｇ
水で２０ｍｌに仕上げる
溶液（Ｇ１）
５６％酢酸水溶液 １８．０ｍｌ
溶液（Ｈ１）
無水炭酸ナトリウム １．７２ｇ
水で１５１ｍｌに仕上げる。
【０２９８】
化合物（Ｋ）：ＨＯ（ＣＨ_２ＣＨ_２Ｏ）_ｎ〔ＣＨ（ＣＨ_３）ＣＨ_２Ｏ〕_１７（ＣＨ_２ＣＨ_２Ｏ）_ｍＨ（ｍ＋ｎ＝５〜７）
特公昭５８−５８２８８号、同５８−５８２８９号に示される混合撹拌機を用いて溶液（Ａ１）に、溶液（Ｂ１）の１／４量及び溶液（Ｃ１）全量を温度４０℃、ｐＡｇ８．０９に制御しながら、同時混合法により４分４５秒を要して添加し、核形成を行った。１分後、溶液（Ｆ１）の全量を添加し、続けて４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラアザインデンの５％水溶液を２０ｍｌ添加した。この間ｐＡｇの調整を、水溶液（Ｅ１）を用いて適宜行った。６分間経過後、溶液（Ｂ１）の３／４量及び溶液（Ｄ１）の全量を、温度２５℃、ｐＡｇ８．０９に制御しながら、同時混合法により１４分１５秒かけて添加した。５分間撹拌した後、溶液（Ｇ１）を全量添加し、ハロゲン化銀乳剤を沈降させた。沈降部分２０００ｍｌを残して上澄み液を取り除き、水を１０Ｌ加え、撹拌後、再度ハロゲン化銀乳剤を沈降させた。沈降部分１５００ｍｌを残し、上澄み液を取り除き、更に水を１０Ｌ加え、撹拌後、ハロゲン化銀乳剤を沈降させた。沈降部分１５００ｍｌを残し、上澄み液を取り除いた後、溶液（Ｈ１）を加え、６０℃に昇温し、更に１２０分撹拌した。最後にｐＨが５．８になるように調整し、銀量１モル当たり１１６１ｇになるように水を添加し、感光性ハロゲン化銀乳剤を得た。
【０２９９】
この乳剤は、平均粒子サイズ０．０３４μｍ、粒子サイズの変動係数１４％、〔１００〕面比率９２％の単分散立方体沃臭化銀粒子であった。
【０３００】
次に、上記乳剤にトリフェニルホスフィンスルフィド（０．５％メタノール溶液）増感剤２４０ｍｌを加え、更に増感剤の１／２０モル相当の塩化金酸増感剤を添加し、５５℃にて１２０分間撹拌して化学増感を施した。これを感光性ハロゲン化銀乳剤とする。
【０３０１】
〈粉末脂肪族カルボン酸銀塩の調製〉
４７２０ｍｌの純水に、ベヘン酸１３０．８ｇ、アラキジン酸６７．７ｇ、ステアリン酸４３．６ｇ、パルミチン酸２．３ｇを８０℃で溶解した。次に１．５Ｍ／Ｌの水酸化ナトリウム水溶液５４０．２ｍｌを添加し、濃硝酸６．９ｍｌを加えた後、５５℃に冷却して脂肪酸ナトリウム溶液を得た。この脂肪酸ナトリウム溶液の温度を５５℃に保ったまま、上記感光性ハロゲン化銀乳剤４５．３ｇと純水４５０ｍｌを添加し５分間撹拌した。
【０３０２】
次に１Ｍ／Ｌの硝酸銀溶液７０２．６ｍｌを２分間かけて添加し、１０分間撹拌し脂肪族カルボン酸銀塩分散物を得た。その後、得られた脂肪カルボン酸銀塩分散物を水洗容器に移し、脱イオン水を加えて撹拌後、静置させて脂肪族カルボン酸銀塩分散物を浮上分離させ、下方の水溶性塩類を除去した。その後、排水の電導度が５０μＳ／ｃｍになるまで脱イオン水による水洗、排水を繰り返し、遠心脱水を実施した後、得られたケーキ状の脂肪族カルボン酸銀塩を、気流式乾燥機フラッシュジェットドライヤー（セイシン企業社製）を用いて、窒素ガス雰囲気及び乾燥機入り口熱風温度の運転条件により、含水率が０．１％になるまで乾燥して粉末脂肪族カルボン酸銀塩を得た。脂肪族カルボン酸銀塩の含水率測定には赤外線水分計を使用した。
【０３０３】
〈予備分散液の調製〉
ポリビニルブチラール樹脂の１４．５７ｇをＭＥＫ１４５７ｇに溶解し、ＶＭＡ−ＧＥＴＺＭＡＮＮ社製：ディゾルバＤＩＳＰＥＲＭＡＴ ＣＡ−４０Ｍ型にて撹拌しながら、粉末脂肪族カルボン酸銀塩の５００ｇを徐々に添加し、十分に混合することにより予備分散液を調製した。
【０３０４】
〈感光性乳剤分散液の調製〉
予備分散液をポンプを用いてミル内滞留時間が１．５分間となるように、０．５ｍｍ径のジルコニアビーズ（トレセラム東レ社製）を内容積の８０％充填したメディア型分散機ＤＩＳＰＥＲＭＡＴ ＳＬ−Ｃ１２ＥＸ型（ＶＭＡ−ＧＥＴＺＭＡＮＮ社製）に供給し、ミル周速８ｍ／ｓｅｃにて分散を行うことにより感光性乳剤分散液を調製した。
【０３０５】
〈添加液Ａの調製〉
１．０ｇのヘテロ原子を含有する下記の大環状化合物Ｓ−１９と、０．３１ｇの酢酸カリウムをメタノール４．９７ｇに溶解し、添加液Ａとした。
【０３０６】
〈赤外増感色素液の調製〉
１９．２ｍｇの下記赤外増感色素１−３（特願２００１−３０８５８２例示化合物）、１．４８８ｇの２−クロロ安息香酸、２．７７９ｇの安定剤２及び３６５ｍｇの５−メチル−２−メルカプトベンズイミダゾールを、３１．３ｍｌのＭＥＫに暗所にて溶解し、赤外増感色素液とした。
【０３０７】
〈添加液ａの調製〉
現像剤として、１，１−ビス（２−ヒドロキシ−３，５−ジメチルフェニル）−オクタン（例示化合物Ａ−８）の１４．０ｇと１．５４ｇの４−メチルフタル酸、０．４８ｇの前記赤外染料１をＭＥＫ１１０ｇに溶解し、添加液ａとした。
【０３０８】
〈添加液ｂの調製〉
３．４３ｇのフタラジンをＭＥＫ４０．９ｇに溶解し、添加液ｂとした。
【０３０９】
〈添加液ｃの調製〉
３．５６ｇのカブリ防止剤２、０．２５ｇのｐ−トルエンチオスルホン酸ナトリウムをＭＥＫ４０．９ｇに溶解し、添加液ｃとした。
【０３１０】
〈画像形成層塗布液の調製〉
不活性気体雰囲気下（窒素９７％）で、前記感光性乳剤分散液５０ｇ及びＭＥＫ１５．１１ｇを撹拌しながら２１℃に保温し、カブリ防止剤１（１０％メタノール溶液）３９０μｌを加え、１時間撹拌した。次に、塩化イリジウムのメタノール溶液をハロゲン化銀１モル当たり１．０×１０^−５モルになるように添加し、更に臭化カルシウム（１０％メタノール溶液）４９４μｌを添加して３０分撹拌した。続いて、０．２１ｇの前記添加液Ａ、１．３２ｇの前記赤外増感色素液を添加して１時間撹拌した。その後、温度を１３℃まで降温して更に３０分撹拌した。１３℃に保温したまま、バインダー樹脂としてポリビニルアセタール樹脂１３．３１ｇを添加して３０分撹拌した後、テトラクロロフタル酸（９．４％ＭＥＫ溶液）１．０８４ｇを添加して１５分間撹拌した。更に撹拌を続けながら、１２．４３ｇの添加液ａ、１．６ｍｌの脂肪族イソシアネート（ＤｅｓｍｏｄｕｒＮ３３００：モーベイ社製）１０％ＭＥＫ溶液、４．２７ｇの添加液ｂ、１０．０ｇの添加液ｃを順次添加し、撹拌することにより画像形成層塗布液を得た。
【０３１１】
〈マット剤分散液の調製〉
セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社製：ＣＡＢ１７１−１５）７．５ｇをＭＥＫ４２．５ｇに溶解し、その中に炭酸カルシウム（Ｓｐｅｃｉａｌｉｔｙ Ｍｉｎｅｒａｌｓ社製：Ｓｕｐｅｒ−Ｐｆｌｅｘ２００）５ｇを添加し、ディゾルバ型ホモジナイザにて８０００ｒｐｍで３０分間分散し、マット剤分散液を得た。
【０３１２】
〈表面保護層塗布液の調製〉
ＭＥＫ８６５ｇを撹拌しながら、これにセルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社製：ＣＡＢ１７１−１５）９６ｇ、ポリメチルメタクリル酸（ローム＆ハース社製：パラロイドＡ−２１）４．５ｇ、ビニルスルホン化合物（ＶＳＣ）１．５ｇ、ベンゾトリアゾール１．０ｇ、弗素系活性剤（旭硝子社製；サーフロンＫＨ４０）１．０ｇを添加し溶解した。次に、上記マット剤分散液３０ｇを添加して撹拌し、表面保護層塗布液を得た。
【０３１３】
各添加液及び塗布液に使用した添加剤の構造を以下に示す。
【０３１４】
【化１４】

【０３１５】
〈銀塩光熱写真材料試料の作製〉
前記下引き済み支持体１上に、上記前記画像形成層塗布液と表面保護層塗布液を、公知のエクストルージョン型コーターを用いて、同時に重層塗布することにより銀塩光熱写真材料試料を作製した。塗布は画像形成層中の銀が、単位体積当たり１×１０^−４ｇ／ｍ^３、表面保護層が乾燥膜厚で２．５μｍになる様にして行った。その後、乾燥温度７５℃、露点温度１０℃の乾燥風を用いて、１０分間乾燥を行い、試料１０１を得た。
【０３１６】
試料１０１において、バッキング層側下引層の添加剤の種類を表２に記載の如く変化させた以外は試料１０１と同様にして、試料１０２〜１１９を作製した。
【０３１７】
〈露光及び現像処理〉
上記で作製した各試料の乳剤面側から、高周波重畳にて波長８００〜８２０ｎｍの縦マルチモード化された半導体レーザーを露光源とした露光機により、レーザー走査による露光を与えた。この際に、試料の露光面と露光レーザー光の角度を７５°として画像を形成した。尚、当該角度を９０°とした場合に比べ、ムラが少なく、かつ予想外に鮮鋭性等が良好な画像が得られた。
【０３１８】
その後、ヒートドラムを有する自動現像機を用いて、試料の保護層とドラム表面が接触するようにして、１１０℃で１５秒熱現像処理した。その際、露光及び現像は２３℃・５０％ＲＨに調湿した部屋で行った。
【０３１９】
〈評価〉
試料１０１〜１１９について、低湿及び熱処理導電性、保存安定性を以下のように評価した。
【０３２０】
《低湿導電性》
試料を２３℃・２０％ＲＨの条件下に２４時間調湿した後、同条件下で川口電気社製テラオームメーターＶＥ−３０を用いて印加電圧１００Ｖで帯電防止層面の表面比抵抗を測定した値をｌｏｇ（Ω／□）で示した。
【０３２１】
《熱処理導電性》
試料を１４０℃のサーモ機中で１８０秒間加熱し、その後２３℃・２０％ＲＨの条件下に２４時間調湿した後、同条件下で川口電気社製テラオームメーターＶＥ−３０を用いて印加電圧１００Ｖで帯電防止層面の表面比抵抗を測定した値をｌｏｇ（Ω／□）で示した。
【０３２２】
《保存安定性》
上記条件で露光、熱現像して得られた画像を濃度計で測定した。
【０３２３】
保存安定性は、４０℃・８０％ＲＨ条件下で１０日間保存した各試料について、２５℃・５５％ＲＨ条件下で保存した場合に対するカブリの変化を読みとり、表２に示した。尚、色調については、目視評価した結果、試料１０１〜１１９何れも、従来市場で受け入れられていたコンベンショナル医用フィルムと略同等であり、非常に好ましいレベルであった。
【０３２４】
【表２】

【０３２５】
表２から明らかなように、本発明の試料は表面比抵抗が低く、熱処理を行っても導電性が劣化しない。又、色調を劣化させることなく、経時カブリの低減が実現できることが判る。
【０３２６】
【発明の効果】
本発明により、有機溶剤や有機アミンを使用しない、環境に対して負荷の少ない帯電防止用水分散液；高温下でもパーコレーション転移が崩れない帯電防止性能に優れた帯電防止層を有するプラスチックフィルム；長期保存においてもカブリ上昇が抑えられた銀塩光熱写真ドライイメージング材料が提供できた。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tin oxide compound composite copolymer aqueous dispersion, a plastic film having an antistatic layer provided with the aqueous dispersion, and a silver salt photothermographic dry imaging material.
[0002]
[Prior art]
Generally, plastic films represented by polyester have excellent optical and mechanical properties, and are used for various applications. However, since the plastic material itself is an insulator, static electricity is generated in various situations, which is a problem during the manufacturing process of optical products and the use by users. For example, in the case of photosensitive materials, especially silver halide photographic materials, each process of coating / winding, cutting, and packaging, when the photosensitive material is opened by the user, transport in a camera or photographing apparatus, before and after development processing by an automatic developing machine In addition, at the time of observation, troubles due to static electricity occur in various situations. Among them, when the accumulated static electricity generated by the contact friction between the surface of the same or different substance or a different substance, etc. is discharged and the silver halide photographic material is exposed to light, or when it is brought into a developing machine or printer, Failures that are conveyed overlapping and jam the machine, that the photosensitive material coming out of the machine sticks together, or that the sheet is discharged when touched by the hand, make the user uncomfortable.
[0003]
In this field where high optical and mechanical properties are required, various antistatic techniques have been proposed that do not impair the excellent physical properties of plastics. For example, antistatic by adding an ionic surfactant is a simple and moderately effective antistatic technology that increases the amount of surfactant used in preparing a coating film until it can be prevented. This is a technique in which it is difficult to maintain the effect forever, for example, the agent comes out of the coating film by transfer or the like. In order to improve this, antistatic processing using an ionic polymer that has been polymerized and made difficult to transfer has the property that the charging performance depends on humidity, and has the disadvantage that static electricity is easily generated in low humidity conditions such as winter. I was
[0004]
Further, the conductive antistatic technique using a π-electron conductive polymer has a drawback of coloring so as not to be affected by humidity, and also has a problem that the π-electron conductive polymer itself is still expensive. As a method for solving this drawback, there is an antistatic technique using metal oxide particles, particularly a tin oxide compound.
[0005]
In general, tin oxide is a semiconductor, and can obtain high conductivity by doping with a different atom, and is a material excellent in transparency, physical and chemical stability. Therefore, a transparent conductive oxide film typified by an ITO film in which tin oxide is doped with indium has been used for various electric and electronic applications.
[0006]
As a method for forming the ITO film, a chemical vapor deposition method, a vacuum vapor deposition method, a reactive ion plating method, a sputtering method, an ion beam sputtering method, and the like are generally used. However, all of these methods have drawbacks in that not only the apparatus is expensive, complicated, and large, but also the film formation speed is slow and a large-area film cannot be obtained. In the case of forming a film, there are problems such as many restrictions on use, such as easy unevenness.
[0007]
In contrast to the above film forming method, a method of applying a composition containing tin oxide to a substrate, for example, a method of applying using a roll coating, a spray coating, an air doctor coating, a bar coater coating, or the like is relatively easy. This is an industrially superior method because a large-area film can be formed and a film can be formed relatively easily even on a site having a complicated shape.
[0008]
As an antistatic technique suitable for such usage, Japanese Patent Application Laid-Open No. 2002-265860 proposes a method using fine particles of a water-dispersible polyester resin containing neopentyl glycol as an essential component and ultrafine particles of tin oxide. This technique has a high transparency and a coating film having a high antistatic property even under low humidity can be obtained. However, when this copolymerized polyester is dispersed in water, it is necessary to use an organic solvent or an organic amine in combination. Therefore, the working environment from dissolution of the copolyester to coating is poor, and water and organic solvents and organic amines that evaporate during coating and drying cannot be released directly into the atmosphere. There was a problem that it became necessary.
[0009]
The antistatic effect of the tin oxide-based compound is achieved by the so-called percolation transition in which the tin oxide compounds adhere to each other in the coating film. However, when used under heat treatment or at a high temperature, there is a problem that the percolation transition is likely to collapse, and the desired antistatic performance is not exhibited after the heat treatment.
[0010]
Next, the silver salt photothermographic dry imaging material will be described.
Silver halide photosensitive materials, which have been widely used in the past, have been used in the field of image formation as a wide range and high quality material due to their excellent photographic characteristics.However, in order to form an image, development, fixing However, there is a disadvantage that the process of washing, drying and drying is required, and the processing is wet, so that the operation is complicated. For this reason, a silver salt photothermographic dry imaging material in which the development process is performed by heat treatment has been developed and put into practical use, and in recent years, it has rapidly become popular mainly in the medical industry.
[0011]
As such a technique, for example, a silver salt photothermographic dry imaging material having an organic silver salt, photosensitive silver halide particles, and a reducing agent on a support (see Patent Documents 1 and 2 and Non-Patent Document 1) is known. . Since this silver salt photothermographic dry imaging material (hereinafter also referred to as silver salt photothermographic material) does not use any solution-based processing chemicals, a simpler system can be provided to the user.
[0012]
The silver salt photothermographic material is heated to a high temperature (for example, 80 ° C. or higher) after image exposure, and a black silver image is formed by an oxidation-reduction reaction between a reducible silver salt (which functions as an oxidizing agent) and a reducing agent. To form The oxidation-reduction reaction is promoted by the catalytic action of the silver halide latent image generated by the exposure. Therefore, a black silver image is formed in the exposed area.
[0013]
However, even with these silver salt photothermographic materials, there is a problem that fog increases as the storage period of the film becomes longer as compared with conventional silver halide photographic materials.
[0014]
A photographic photosensitive material containing a composite polymer obtained by polymerizing a hydrophilic monomer in the presence of a metal oxide (see Patent Document 3) and a composite polymer obtained by polymerizing a hydrophobic monomer in the presence of a metal oxide Although a photographic light-sensitive material containing the same (see Patent Document 4) and the like have been proposed, the problem that fog increases as the storage period of a film becomes longer has not yet been solved.
[0015]
[Patent Document 1]
U.S. Pat. No. 3,152,904
[0016]
[Patent Document 2]
U.S. Pat. No. 3,487,075
[0017]
[Non-patent document 1]
D. Morgan: Dry Silver Photographic Materials (Handbook of Imaging Materials, Marcel Dekker, Inc.) p. 48, 1991.
[0018]
[Patent Document 3]
JP-A-8-201949
[0019]
[Patent Document 4]
JP-A-8-211537
[0020]
[Problems to be solved by the invention]
A first object of the present invention is to provide an antistatic aqueous dispersion which does not use an organic solvent or an organic amine and has a low environmental load. A second object is to provide a plastic film having an antistatic layer having excellent antistatic performance (conductivity), in which percolation transition does not collapse even at a high temperature. A third object of the present invention is to provide a silver salt photothermographic dry imaging material in which fog is suppressed even during long-term storage.
[0021]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions.
[0022]
1) A composite copolymer aqueous dispersion obtained by dispersion-polymerizing a vinyl monomer in an aqueous dispersion in which a tin oxide-based compound and a water-dispersible copolymerized polyester are mixed.
[0023]
The composite copolymer contains 2) an active methylene group, 3) a glycidyl group, 4) an amide group, 5) a nitrile group, and 6) a hydroxyl group. And 7) containing a carboxyl group are all preferred embodiments.
[0024]
In a preferred embodiment, the tin oxide-based compound is 8) tin oxide, 9) antimony-doped tin oxide, 10) indium-doped tin oxide, and 11) fluorine-doped tin oxide. .
[0025]
12) A plastic film having an antistatic layer formed by coating the aqueous dispersion of the composite copolymer according to any one of 1) to 11) on a plastic film directly or via another layer.
[0026]
13) A silver salt photothermographic dry imaging material obtained by applying the aqueous composite copolymer dispersion according to any one of 1) to 11) directly or via another layer on a plastic film.
[0027]
Hereinafter, the present invention will be described in detail.
The copolymerized polyester in the present invention is a linear polymer obtained by a polycondensation reaction between a polybasic acid or an ester-forming derivative thereof and a polyol or an ester-forming derivative thereof, and contains sulfonic acid or a metal salt thereof. A dicarboxylic acid component is required. Examples of the sulfonic acid-containing dicarboxylic acids include 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, sulfoterephthalic acid, sulfosuccinic acid, 2,5-bis (hydroxyethoxy) benzenesulfonic acid, and 4,4′-bis (hydroxy (Ethyl) disulfonylbisphenol A or a portion of the sulfonic acid group is converted to an alkali metal salt, and 5-sulfoisophthalic acid or its sodium salt is particularly preferable.
[0028]
The molar fraction of the dicarboxylic acid component having an alkali metal sulfonate group with respect to all the dicarboxylic acid components constituting the copolymerized polyester is 5 to 15 mol%, so that the copolymer can be dispersed in water with hot water without using an organic solvent.
[0029]
Other polybasic acids used in the copolymerized polyester include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, Alicyclic dicarboxylic acids such as 4'-bicyclohexyldicarboxylic acid can be mentioned. This component preferably contains at least 5 to 20 mol% of all polybasic acids from the viewpoint of improving the water resistance of the coating film. The polybasic acid preferably contains an aromatic dicarboxylic acid, particularly terephthalic acid and isophthalic acid, in an amount of 50 to 80 mol% based on the total dicarboxylic acid component, and the ratio of terephthalic acid to isophthalic acid is 30/70 in molar ratio. It is particularly preferably from 70 to 30/30 in view of applicability to a plastic film, solubility in hot water, and mechanical strength of the coating film.
[0030]
As another polybasic acid component, an aliphatic dicarboxylic acid such as adipic acid may be contained.
[0031]
Examples of the glycol to be reacted with the above polybasic acid or its ester-forming derivative or its ester-forming derivative include ethylene glycol, diethylene glycol, 1,4-butanediol, dipropylene glycol, 1,6-hexanediol, 1,4 -Cyclohexanedimethanol, xylylene glycol, poly (ethylene oxide) glycol, poly (tetramethyleneoxide) glycol, etc., among which ethylene glycol and 1,4-cyclohexanedimethanol are preferred.
[0032]
Various known methods can be used to polymerize the copolymerized polyester. For example, it can be obtained by a production method in which an initial condensate of a dicarboxylic acid and a glycol is formed by an ester exchange method or a direct esterification method, and this is melt-polymerized. More specifically, for example, a transesterification reaction is performed between an ester of dicarboxylic acid (dimethyl ester of dicarboxylic acid) and glycol, and after methanol is distilled off, polycondensation is performed under reduced pressure and high vacuum. Method, conduct esterification reaction of dicarboxylic acid and glycol, distill off the generated water, gradually reduce the pressure, perform polycondensation under high vacuum, transesterification reaction between dicarboxylic acid ester and glycol And then performing an esterification reaction by further adding a dicarboxylic acid, followed by polycondensation under high vacuum.
[0033]
As the transesterification catalyst and the polycondensation catalyst, known catalysts can be used. As the transesterification catalyst, manganese acetate, calcium acetate, zinc acetate and the like can be used. As the polycondensation catalyst, antimony trioxide, germanium oxide, dibutyltin can be used. Oxide, titanium tetrabutoxide and the like can be used. However, various conditions such as a polymerization method and a catalyst to be used are not limited to the above examples.
[0034]
Such a copolymerized polyester preferably has a glass transition temperature (Tg) in the range of 45 to 90 ° C. from the viewpoints of blocking prevention and hot water dispersibility when storing the copolymerized polyester.
[0035]
After completion of the polycondensation, the copolymerized polyester of the present invention is sent to a pelletizer in a molten state, and there is no particular limitation on the shape, but various shapes such as a cylindrical shape, a flat cylindrical shape, a hexahedral shape, a spherical shape, an elliptical shape, and a flaky shape are used. It is extruded and cooled to a shape and stored as pellets. If the size of the pellet is too large, it is difficult to disperse in water. Therefore, the size of the pellet is preferably 5 g or less per 100 pellets, and particularly preferably 1 to 4 g per 100 pellets.
[0036]
The solvent for dispersing the polyester is mainly composed of water, but may contain a small amount of additives other than water as long as the physical properties of the copolymerized polyester are not impaired. Examples of additives other than water include anionic and nonionic surfactants, water-soluble polymers, salts such as ammonium sulfate and lithium bromide.
[0037]
In preparing a pellet dispersion, a stirrer with a propeller-type, turbine-type, or half-moon-type stirring blade can be used to disperse the pellet in an aqueous medium by stirring, but the shape of the stirring blade is not limited thereto. The addition of the pellets is preferably performed in a stirred aqueous medium before the addition. If the polyester is heated to Tg or more immediately after the addition, the pellets tend to be agglomerated, so it is important to gradually add the pellets to the place where the mixture is being stirred. The stirring is performed to such an extent that the pellets do not settle and stick. The copolymerized polyester of the present invention swells between Tg and 90 ° C., and once becomes in a state where the fluidity of the system is lost, the fluidity comes out at a temperature exceeding 90 ° C., and the material becomes translucent. It becomes a liquid with low viscosity.
[0038]
The heating temperature for dispersing in water is preferably 90 ° C. or higher. If the temperature is lower than 90 ° C., the dispersion is extremely slow or substantially difficult to disperse. Further, at a temperature exceeding the boiling point of water under atmospheric pressure, heating under pressure is necessary, which not only complicates equipment, but also hydrolyzes the copolymerized polyester and easily reduces the molecular weight. The temperature is preferably 98 ° C. or lower.
[0039]
Hereinafter, synthesis examples of the copolymerized polyester used in the present invention will be described. Note that “parts” in the synthesis examples indicates “parts by mass”.
[0040]
<Copolymer polyester 1>
34.07 parts of dimethyl terephthalate, 32.36 parts of dimethyl isophthalate, 17.94 parts of dimethyl sodium 5-sulfoisophthalate, 56.01 parts of ethylene glycol, 0.065 part of calcium acetate monohydrate, manganese acetate tetrahydrate 0.022 parts of the salt was subjected to a theoretical amount of methanol distillation at 170 to 220 ° C. under a nitrogen stream, and further subjected to a transesterification reaction. Thereafter, 0.04 part of trimethyl phosphate, 0.04 part of antimony trioxide as a polycondensation catalyst and 6.04 parts of 1,4-cyclohexanedicarboxylic acid were added. Thereafter, at a reaction temperature of 220 to 235 ° C., almost the theoretical amount of water was distilled off and esterification was performed. Thereafter, the pressure inside the reaction system was further reduced over about 1 hour, and the temperature was raised. Finally, polycondensation was performed at 280 ° C. and 133.3 Pa or lower for about 1 hour to obtain a copolymerized polyester. The intrinsic viscosity of the obtained copolymerized polyester is 0.33, and the composition of the polybasic acid is as follows: dicarboxylic acid having sulfonic acid / alicyclic dicarboxylic acid / terephthalic acid / isophthalic acid = 8/14/40/38 ( Molar ratio).
[0041]
Next, the tin oxide-based compound will be described.
Tin oxide compounds that can be used in the present invention are tin oxide, antimony-doped tin oxide, indium-doped tin oxide, fluorine-doped tin oxide, aluminum-doped tin oxide, tungsten-doped tin oxide, titanium oxide-cerium oxide-tin oxide composite, A composite of titanium oxide and tin oxide can be given.
[0042]
The tin oxide of the present invention will be described. It is known that high-purity, colorless and transparent crystalline tin oxide has a tetragonal rutile structure, a refractive index of 1.9968, and a high electrical conductivity of 106 Ωcm or more at room temperature. The melting point is 1127 ° C., and amorphous tin oxide is a substance which does not show the above properties, the temperature is in a range where the arrangement of atoms is not regular and the substance changes below the melting point of crystalline tin oxide. Is a tin oxide.
[0043]
Such tin oxide can be manufactured as follows. The step of producing the aqueous dispersion containing tin oxide includes a step of hydrolyzing a hydrolyzable tin compound and a step of washing the hydrolyzate with water. The tin oxide is dried and heated to 500 ° C. or more in an electric furnace or the like to be crystallized. The crystallized tin oxide is dispersed in water by a mechanical dispersion method. In the case of amorphous tin oxide, the dispersion is easier than that of crystalline tin oxide, and the pH is adjusted during or after washing with water to disperse. At this time, the washing step and the pH adjusting step may be performed simultaneously. Further, the step of mechanically dispersing may be performed after the washing step or after the pH adjustment step. Further, the present invention does not limit that each step is further subdivided.
[0044]
The raw material of tin oxide is a hydrolyzable tin compound, which is hydrolyzed to prepare amorphous tin oxide. The tin compound is K₂SnO₃・ 3H₂Compounds containing oxo anions such as O, SnCl₄, SnCl₄・ 5H₂Water-soluble halides such as O, tin oxide, tin hydroxide, or organic or inorganic salts of tin (stannic salts, stannic salts) such as tin acetate, tin oxalate, tin sulfate, tin nitrate, tin Alkali stannates such as potassium silicate and sodium stannate, and (C₂H₅)₄Sn, (CH₃)₃SnOC₂H₅, (C₄H₉)₂Sn (OCOC₂H₅)₂, (C₂H₅)₂SnCl₂, (CH₃)₃SnCl ・ C₅H₅Organic tin compounds such as N, Sn (SO₄)₂・ 2H₂Examples include compounds containing an oxo salt such as O. These may be used alone or as a mixture of two or more. Among them, it is industrially desirable to use an aqueous solution of tin chloride in hydrochloric acid. When producing tin oxide, tin oxide is obtained by adding tin chloride to pure water or an aqueous alkali metal solution and hydrolyzing it.
[0045]
In the hydrolysis step, the temperature condition when the tin compound is added to water is important, and is preferably from 10 to 50C, more preferably from 15 to 45C, and particularly preferably from 20 to 40C. It is preferable that the tin compound is dividedly charged, and in this case, the second and subsequent doses are preferably 以下 or less, preferably １ ／ or less of the first dose. The temperature of the hydrolysis step after the addition of the tin compound is preferably 72 to 98 ° C. In split charging of the tin compound, it is preferable that the second and subsequent charging be performed 1 to 25 minutes after the first charging. In the step of washing the hydrolyzed amorphous tin oxide with water, appropriate filtration such as decantation or ultrafiltration, in which solid-liquid separated amorphous tin oxide is separated into a supernatant and the supernatant is discarded, and the supernatant is discarded , The amorphous tin oxide can be separated and taken out, but is not limited thereto.
[0046]
For decantation, it is preferable to use pure water so that unnecessary components are not newly added. By discarding the water content of the supernatant of the precipitated amorphous tin oxide, chlorine ions (here, hydrolyzed stannic chloride and thus chloride ions) and soluble metal compounds can be efficiently removed. Since all water cannot be removed, the amorphous tin oxide becomes a slurry. In order to accelerate the precipitation of the amorphous tin oxide, it is preferable to heat to about 40 ° C. In this step, washing with water is preferably repeated about several times to about 20 times.
[0047]
In this state, the tin oxide may be dried, taken out, and fired to obtain crystalline tin oxide. However, the tin oxide may be dispersed in water in an amorphous state by adjusting the pH. For example, as a step of preparing an aqueous dispersion containing amorphous tin oxide, the pH is adjusted to 6.0 to 7.5 using an alkaline aqueous solution, preferably to 6.5 to 7.0. Adjust so that The alkaline aqueous solution is an alkaline aqueous solution such as lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, and ammonia. In this pH adjusting step, the pH may be adjusted at once with an aqueous alkali solution, or the pH may be adjusted to the above range by dividing it into several times. The latter is preferred because it is easier to control. When the pH comes into the above range, the slurry-like material shifts to a smooth and low-viscosity state. When the pH is adjusted to 9.5 to 10.5 with ammonia, the aqueous dispersion becomes more transparent and has a low viscosity of 1 to 2 mPa · s.
[0048]
When the aqueous dispersion containing tin oxide is thin, it may be concentrated. The concentration is preferably performed using an ultrafiltration membrane so as not to deteriorate the dispersibility of the amorphous tin oxide. Further, ultrasonic dispersion or mechanical dispersion may be performed in order to bring the particles in the slurry into an appropriate dispersion state or to facilitate pH adjustment. In particular, the aggregated particles can be pulverized, and the dispersibility can be improved. Also, a mechanical dispersion method may be used in order to make the particle size uniform. As the mechanical dispersion method referred to in the present invention, a method using a medium mill, a colloid mill, high-speed shear stirring, high-pressure impact dispersion, or the like is preferable. Specific examples of the media mill include a ball mill, an attritor, a sand mill, and a bead mill. Specific examples of the colloid mill include a colloid mill, a stone mill, a caddy mill, and a homogenizer. Specific examples of the high-speed shearing and stirring apparatus include those called high-speed dispersers, high-speed impellers and dissolvers as trade names.
[0049]
Hereinafter, an example of a method for synthesizing the aqueous dispersion of tin oxide will be described.
<Tin oxide compound 1 (tin oxide)>
200 liters of pure water was put into a 300 liter reactor equipped with a dropping funnel, a thermometer, and a stirring rod, and 5.4 kg of anhydrous stannic chloride was put into the dropping funnel. While stirring the inside of the flask with a stirring rod, 4.8 kg of anhydrous stannic chloride was first dropped from the dropping funnel and stirred for 5 minutes. Thereafter, 0.5 kg of anhydrous stannic chloride was dropped and stirred for 5 minutes, and then the remaining anhydrous stannic chloride was dropped. After dropping the entire amount of the second tin chloride, the dropping funnel was removed and replaced with a tube bent into a U-shape. The tip of the tube was immersed in an aqueous solution of sodium carbonate. Thereafter, the kettle was heated with steam, and the inside of the kettle was kept at 85 ° C. As the temperature approached 85 ° C., the inside of the flask became cloudy. While intermittently stirring the inside of the kettle, it was kept warm for 1 hour, water-cooled, and when the internal temperature reached 60 ° C., the hydrolyzed content in the flask was poured into 1,000 liters of pure water at 40 ° C. . Waiting for the slurry to settle and spontaneously settle, the supernatant was discarded when the bulk of the slurry became 1/3 in water. To this, 600 liters of pure water at 40 ° C. was added, and further, sedimentation was performed, and decantation was repeated 17 times. In the course of 17 times of decantation, an aqueous solution of 1 mol / L sodium hydroxide was poured so that the pH became 6.8. After the 17th decantation, the solid content of tin oxide (solid content after heating and drying at 800 ° C. for 1 hour) was further increased to 17.5 using a SEP-1013 ultrafiltration membrane (manufactured by Asahi Kasei Corporation). Concentration was performed until the concentration became mass% to prepare an aqueous dispersion of tin oxide compound 1. The aqueous dispersion of this tin-based oxide was measured with ELS-800 (laser scattering particle size analyzer manufactured by Otsuka Electronics Co., Ltd.), and the particle size at a frequency of 50% was found to be 55 nm.
[0050]
(Antimony-doped tin oxide)
Next, antimony-doped tin oxide will be described. Examples of the newly used antimony compounds include antimony halides such as antimony chloride, inorganic salts such as antimony oxide, antimony hydroxide or antimony sulfate, and these may be used alone or in combination of two or more. May be used. Among them, it is industrially desirable to use an aqueous solution of antimony chloride in hydrochloric acid. The addition amount of antimony oxide is 1 to 30% by mass, preferably 5 to 20% by mass based on tin oxide.
[0051]
As a production method, first, a tin chloride solution is neutralized with an alkali to produce a tin oxide hydrate. Next, a solution of antimony chloride may be neutralized with an alkali to generate a hydrate of antimony oxide, or tin chloride and antimony chloride may be mixed in advance, and a hydrate may be prepared in the same manner. It does not matter. The neutralization reaction of each solution of tin chloride and antimony chloride is performed, for example, by (a) adding each solution of tin chloride or antimony chloride and an aqueous alkali solution in hot water in parallel to neutralize the solution; Alternatively, there may be mentioned a method of neutralizing by adding an aqueous alkali solution to each solution of antimony chloride, and (c) adding each solution of tin chloride or antimony chloride to an aqueous alkali solution for neutralization. Among them, the method (a) is particularly industrially desirable. In this case, the neutralization reaction solution is preferably maintained at a pH of 3 or more, preferably 5 to 10.
[0052]
The neutralization reaction is desirably carried out under heating or in hot water, but can be carried out at room temperature without heating. Examples of the alkaline aqueous solution used as the neutralizing agent include hydroxides, carbonates, and ammonia of alkali metals such as sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. Examples of the acidic aqueous solution include hydrochloric acid and sulfuric acid. And these may be used alone or in combination of two or more.
[0053]
Next, the product is filtered from the reaction solution after the completion of the neutralization reaction, and if necessary, washed and collected. In this case, it is preferable to add an acid to the reaction solution after the neutralization reaction to adjust the pH of the reaction solution to 5 or less, preferably 2 to 4, and then filter the product. When a hydroxide or carbonate of an alkali metal is used as a neutralizing agent, if the alkali metal is adsorbed and remains on the product due to insufficient washing, the alkali metal is converted into SnO of Sb in a firing step described later.₂Since Sb interferes with solid solution in the crystal,₂When a solid solution is formed in the crystal, it is necessary to perform sufficient washing so that no alkali metal remains. In addition, in the step of forming a hydrate of tin oxide, it is preferable that the salt generated by neutralization is removed by washing, and then subjected to a step of forming a hydrate of antimony oxide.
[0054]
The collected product is dried if necessary, and then calcined at a temperature of 400 to 800C, preferably 500 to 700C. When silicon oxide (hydrate) is contained in the precipitate, the silicon compound suppresses sintering of the particles during firing, and finer particles can be obtained. The firing time is suitably from 30 minutes to 5 hours. After firing, the powder is dried and pulverized according to a conventional method to obtain a conductive fine powder. Indium-doped tin oxide can be obtained in a similar manner.
[0055]
Hereinafter, specific examples of antimony-doped tin oxide and indium-doped tin oxide will be described.
[0056]
<Tin oxide based compound 2 (antimony-doped tin oxide)>
SN100S (manufactured by Ishihara Sangyo Co., Ltd .: antimony-doped tin oxide sol solids concentration: 17.5%). The 50% particle size was 51 nm.
[0057]
<Tin oxide based compound 3 (indium-doped tin oxide)>
240 g of stannous chloride and 5.7 g of indium chloride were dissolved in 1600 ml of pure water, and the mixture was reacted while dropping 226 g of 25 mass% aqueous ammonia at a rate of 5 ml / min while stirring at 50 ° C. Was. The obtained precipitate was washed ten times with pure water and filtered. Next, it was dried at 60 ° C. under atmospheric pressure and calcined at 550 ° C. for 1 hour to obtain indium-doped tin oxide fine particles. The obtained fine particles were dispersed in the same manner as in the aqueous dispersion sample 2 to prepare an aqueous dispersion of indium-doped tin oxide (an aqueous dispersion of the tin oxide-based compound 3). The 50% particle size of the indium-doped tin oxide was 45 nm.
[0058]
Next, the fluorine-doped tin oxide used in the present invention will be described. Fluorine-doped tin oxide powder is produced by mixing a solution of a stannic salt with an aqueous solution of fluoride and separating the precipitate of tin hydroxide formed from the liquid. The precipitate is dried at a temperature not exceeding around room temperature and then calcined by briefly heating to a temperature of at least 500 ° C. During firing, the powder is heated until the fluorine content of the powder is at most 10% by weight, preferably 1 to 5% by weight. Known stannic salts of water, such as stannic sulfate and stannic chloride, can be used. It is preferable to use stannic chloride dissolved in water. The water-soluble fluoride can be, for example, sodium fluoride, ammonium fluoride or stannous fluoride. The latter materials are preferred because they usually produce tin oxide powders having lower resistance than powders made from sodium or ammonium fluoride under the same conditions.
[0059]
The calcination of the dried tin hydroxide is performed by heating the tin hydroxide for a while in air or an inert gas such as nitrogen. In the case of calcination in air, a powder having a fluorine content of 1 to 5% by mass and a resistance reaching a minimum value is obtained quite quickly and within 15 minutes. If the calcination is performed in nitrogen, the progress is slow, so that the control is more sufficiently performed so as to obtain a product of a constant quality. In this case, the firing time can be several hours.
[0060]
The calcination of the tin hydroxide can be performed immediately after the drying of the tin hydroxide or at some time thereafter. The drying of the tin hydroxide prior to calcination is because the prior drying step has a beneficial effect on the final tin oxide powder particle size. Drying is performed under appropriate conditions, preferably at room temperature or lower. One interesting drying method is freeze drying.
[0061]
Furthermore, when producing tin oxide, the formation of fine particles is promoted by mixing the salt solution with rapid and vigorous stirring and adding the stannic salt solution, preferably to a fluoride solution.
[0062]
The tin oxide-based compound thus obtained is extremely preferably prepared by subjecting a powder to wet pulverization to prepare an aqueous dispersion in order to reduce the dispersion energy.
[0063]
The solid concentration of the aqueous dispersion is 1 to 70% by mass, preferably 10 to 50% by mass, and the pH is 4 to 12, preferably 5 to 10. Examples of the wet dispersion method include a ball mill, a sand mill, a colloid mill, an ultrasonic dispersion, a jet mill, and a high-speed impeller disperser. Among them, a sand mill using beads is preferably used. It is preferable to use ceramics, particularly zirconia, as beads to be used, and it is preferable to first disperse the beads with large beads of several mm, and then gradually disperse them into smaller beads and disperse them.
[0064]
Hereinafter, a synthesis example of fluorine-doped tin oxide will be described.
<Tin oxide based compound 4 (fluorine-doped tin oxide)>
176.25 g of tin chloride and 8.6 g of silicon chloride were placed in 3000 ml of pure water, and further added to a 7500 ml solution of pure water containing 125 g of ammonium fluoride with vigorous stirring. During the addition, the pH of the reaction mixture was maintained at about 3.5 by dropwise addition of ammonia. After completion of the addition, the mixture was adjusted to pH 7 by adding ammonia, the precipitate was separated from the liquid by centrifugation, dried by freeze-drying, and the obtained powder was calcined at 500 ° C. for 60 minutes under a stream of dry nitrogen to obtain an atomizer ( The powder was pulverized with a fine pulverizer manufactured by Fuji Paudal Co., Ltd. to obtain a fine powder of fluorine-doped tin oxide.
[0065]
150 g of the obtained fine powder B and 350 g of pure water are mixed, and the mixture is dispersed for 1 hour using a homomixer. Further, the mixture is placed in a planetary ball mill together with zirconia beads having a diameter of 0.5 mm, and dispersed for 1 hour to obtain fluorine-doped tin oxide. (Aqueous dispersion of tin oxide-based compound 4) was prepared. The 50% particle size of the fluorine-doped tin oxide was 80 nm.
[0066]
Next, the aqueous composite copolymer dispersion of the present invention will be described.
The aqueous dispersion of the composite copolymer is obtained by emulsion polymerization or suspension polymerization of a vinyl monomer in an aqueous dispersion obtained by mixing a tin oxide-based compound and a water-dispersible copolymerized polyester. At this time, there is no particular limitation on the method for preparing an aqueous dispersion in which the tin oxide-based compound and the water-dispersible copolymerized polyester are mixed, and after preparing a copolymerized copolyester aqueous dispersion in advance, mixing the tin oxide-based compound. Alternatively, it may be prepared by heating an aqueous dispersion of a tin oxide compound and dispersing the copolymerized copolyester pellets in the dispersion.
[0067]
The aqueous dispersion of the composite copolymer in the present invention preferably contains an active methylene group from the viewpoint of suppressing fog with time.
[0068]
The composite copolymer containing an active methylene group can be obtained by mixing an active methylene group-containing vinyl monomer alone or other It is obtained by emulsion polymerization or suspension polymerization of a mixture with a vinyl monomer.
[0069]
Examples of the vinyl monomer having active methylene include acetoacetoxyethyl (meth) acrylate, N-acetoacetoxyethyl (meth) acrylamide, N-acetoacetoaminoethyl (meth) acrylamide, N-acetoacetoaminopropylacrylamide, Acetoxypropyl (meth) acrylate and the like can be mentioned.
[0070]
It is desirable that the aqueous dispersion of the composite copolymer in the present invention contains a glycidyl group from the viewpoint of suppressing fog over time.
[0071]
The glycidyl group-containing composite copolymer can be obtained by mixing a glycidyl group-containing vinyl monomer alone or another vinyl monomer in an aqueous dispersion obtained by mixing a tin oxide compound and a water-dispersible copolymerized polyester. It is obtained by subjecting a mixture with a monomer to emulsion polymerization or suspension polymerization.
[0072]
Examples of the vinyl monomer containing a glycidyl group include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, glycidyl allyl ether, and 3,4. -Epoxycyclohexyl allyl ether and the like.
[0073]
The aqueous dispersion of the composite copolymer in the present invention desirably contains an amide group from the viewpoint of suppressing fog over time.
[0074]
The amide group-containing composite copolymer is prepared by mixing an amide group-containing vinyl monomer alone or another vinyl monomer in an aqueous dispersion obtained by mixing a tin oxide compound and a water-dispersible copolymerized polyester. It is obtained by subjecting a mixture with a monomer to emulsion polymerization or suspension polymerization.
[0075]
Examples of vinyl monomers having an amide group include (meth) acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, and N-dimethylamino. Propyl methacrylamide and the like can be mentioned.
[0076]
The aqueous dispersion of the composite copolymer in the present invention desirably contains a nitrile group from the viewpoint of suppressing fog over time.
[0077]
The nitrile group-containing composite copolymer is obtained by mixing a nitrile group-containing vinyl monomer alone or another vinyl monomer in an aqueous dispersion obtained by mixing a tin oxide compound and a water-dispersible copolymerized polyester. It is obtained by subjecting a mixture with a monomer to emulsion polymerization or suspension polymerization.
[0078]
Examples of the vinyl monomer containing a nitrile group include (meth) acrylonitrile, vinylidene cyanide, α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, α-chloro-β-difluoroacrylonitrile, and α-triol. Examples include fluoromethylacrylonitrile, α-methoxyacrylonitrile, α-vinyl vinyl acetate, α-cyanostyrene, and N, N-bis-β-cyanoethylacrylamide.
[0079]
The aqueous dispersion of the composite copolymer in the present invention desirably contains a hydroxyl group from the viewpoint of suppressing fog over time.
[0080]
This hydroxyl-containing composite copolymer is obtained by mixing a hydroxyl-containing vinyl monomer alone or another vinyl monomer in an aqueous dispersion obtained by mixing a tin oxide-based compound and a water-dispersible copolymerized polyester. It is obtained by subjecting a mixture with a body to emulsion polymerization or suspension polymerization.
[0081]
Examples of the vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxy Butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl allyl ether, 2-hydroxypropyl allyl ether, 3-hydroxypropyl allyl ether, 4-hydroxybutyl allyl ether, allyl alcohol, etc. may be mentioned. I can do it.
[0082]
The aqueous dispersion of the composite copolymer in the present invention desirably contains a carboxyl group from the viewpoint of suppressing fog with time.
[0083]
The carboxyl group-containing composite copolymer can be obtained by mixing a carboxyl group-containing vinyl monomer alone or other vinyl monomers in an aqueous dispersion obtained by mixing a tin oxide compound and a water dispersible copolymerized polyester. It is obtained by emulsion polymerization or suspension polymerization of a mixture with a monomer.
[0084]
Examples of the vinyl monomer having a carboxyl group include, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, sorbic acid, propiolic acid, and the like. Can be done.
[0085]
Other vinyl monomers include acrylic monomers such as alkyl (meth) acrylate (where the alkyl group is methyl, ethyl, propyl, i-propyl, butyl, i-butyl, t-butyl, Ethylhexyl, cyclohexyl, benzyl, phenethyl and the like). Examples of the vinyl monomer other than the acrylic monomer include sulfonic acid groups such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, etc.) or salts thereof. Monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride; aromatics such as styrene, α-methylstyrene, t-butylstyrene, p-chlorostyrene, chloromethylstyrene and vinyltoluene Group vinyl monomers; and vinyl ester monomers such as vinyl formate, vinyl acetate, and vinyl propionate.
[0086]
The amount of the vinyl monomer used is preferably such that the (copolymerized polyester) / (vinyl monomer) ratio is in the range of 99/1 to 5/95 by mass, and 97/3 to 20/80. More preferably, it is within the range.
[0087]
If the (copolyester) / (vinyl monomer) ratio is too high, stable polymerization of the vinyl monomer may not be obtained. Conversely, if the (copolymerized polyester) / (vinyl monomer) ratio is too low, the effect of the present invention will be weakened.
[0088]
As the polymerization initiator used, in emulsion polymerization, organic or inorganic peroxides, acetyl peroxide, acetic peroxide, hydrogen peroxide, percarbonate, persulfate, persalts such as perborate and the like can be used. .
[0089]
The polymerization can be carried out without using a surfactant, but it is also possible to use a surfactant as an emulsifier for the purpose of improving polymerization stability. In this case, any of nonionic and anionic surfactants can be used. Further, if necessary, mercaptans or the like which is a molecular weight modifier may be added.
[0090]
The polymerization conditions are preferably changed according to the method of adding each component to the polymerization system, the addition concentration, the temperature, the pressure during the polymerization reaction, and the stirring conditions. The monomer may be added in a calculated amount, or may be added in an excess amount and collected after the completion of the reaction. If necessary, a stabilizer, a reaction accelerator, a crosslinking agent and the like may be added before or during the synthesis. To the latex after completion of the synthesis, a pH adjuster, a surfactant, a dispersion stabilizer, a wetting agent, and the like, which are conventional methods for imparting stagnant stability, may be further added.
[0091]
The concentration of the polymerization initiator is preferably from 0.15 to 0.7 mol% based on the total amount of the added monomers. The concentration of the polymerization initiator is related to the magnitude of the molecular weight (or degree of polymerization) of the finished polymer. If the amount is small, a polymer having a large molecular weight can be obtained, but the amount of the residual monomer increases, and When the amount is large, only a polymer having a small molecular weight can be obtained, and when a film is formed, only a film having a low film strength can be obtained.
[0092]
In a polymerization system of a polymer latex, a polymerization initiator and a monomer are added after adding a monomer component of 5 to 20% by mass of the total added monomer component to a solvent as a premonomer, and the polymerization proceeds stably, and the viscosity is stable with time. The performance is improved. Furthermore, the formation of aggregates can be reduced, and the yield can be increased. In addition, the amount of residual monomer is reduced, which is preferable in working environment.
[0093]
The polymerization initiation temperature is preferably from 30 to 90C, more preferably from 50 to 90C. This polymerization initiation temperature refers to the liquid temperature when the polymerization initiator is added.
[0094]
Next, the coating composition of the antistatic layer of the present invention will be described.
The antistatic layer coating composition refers to a dispersion obtained by adding a surfactant, a polymer latex or a water-soluble resin, a matting agent, and the like, as necessary, to the aqueous dispersion of the above-described composite copolymer. Surfactants are used to improve coating properties when applying the antistatic layer coating composition to a plastic film, and dispersants such as anionic surfactants, cationic surfactants, and nonionic surfactants, and coating aids. And surface tension adjusters. Polymer latex or water-soluble resin is used to further strengthen the strength of the antistatic layer as a film, and a matting agent controls the coefficient of friction and prevents "sticking" when wound, or makes it easier to wind. Silicon oxide fine particles, titanium oxide fine particles, cross-linkable polymer fine particles, and the like can be used to impart a function of performing the above.
[0095]
The content of the tin oxide-based compound in the antistatic layer coating composition is preferably from 35 to 80% by mass. Further, the addition amount of the copolymerized polyester is preferably 20 to 65% by mass, and the addition amount of other components is preferably 0 to 15% by mass. The addition amount of the tin oxide compound and the copolyester at this time indicates a component in the addition amount of the aqueous dispersion of the composite copolymer.
[0096]
The base film of the plastic film having the antistatic layer according to the present invention will be described.
[0097]
As the base film used in the present invention, for example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, modified polyester film containing metal sulfoaromatic dicarboxylic acid, polyester containing metal sulfoaromatic dicarboxylic acid and PET and / or PEN Polyester film, Polycarbonate (PC) film, Polyamide film, Polyimide film, Polyphenylene sulfone film, Polyphenylene ether film, Cellulose triacetate (TAC) film, Cellulose acetate propionate film, Polyethylene (PE) film and Polypropylene laminated Paper, etc., but are not limited thereto. Among them, PET film, PEN film, modified polyester film containing metal sulfo aromatic dicarboxylic acid, polyester film having a laminated structure of polyester containing metal sulfo aromatic dicarboxylic acid and PET and / or PEN, PC film, TAC film, cellulose acetate Propionate films are preferred.
[0098]
The base film may contain phosphoric acid, phosphorous acid and esters thereof, phthalic acid esters, and inorganic particles (silica, kaolin, calcium carbonate, calcium phosphate, titanium dioxide, etc.), and may appropriately contain pigments, ultraviolet rays, etc. An absorbent, an antioxidant, a matting agent, a slipping agent, a stabilizer, a surfactant, a dispersant, an antiadhesive, a softener, a fluidity-imparting agent, and the like may be added.
[0099]
The plastic film having an antistatic layer of the present invention is obtained by coating the antistatic layer coating composition directly or via another layer on the film. Other layers include an undercoat layer and a back layer. An upper layer may be provided on the antistatic layer, and the upper layer may be a protective layer as an outermost layer. The protective layer may contain a matting agent, a slipping agent, and the like.
[0100]
The application of the antistatic layer coating composition can be performed by a method such as dip coating, air knife coating, spraying or extrusion coating using a hopper described in US Pat. No. 2,681,294. Further, according to U.S. Pat. Nos. 3,508,847, 2,941,898, and 3,526,528, other layers may be simultaneously applied.
[0101]
The coating amount of the antistatic layer coating composition is such that the coating amount of the tin oxide compound is 0.0001 to 2 g / m2.²And more preferably 0.001 to 1 g / m²It is. The surface resistance value of the antistatic layer surface is preferably 8.0 to 12.0 as log (Ω / □) even in a low humidity state of 23 ° C. and 20% RH (relative humidity).
[0102]
The plastic film having an antistatic layer according to the present invention includes a support for a silver halide photographic material, a support for a photothermographic material, a protective film for a polarizing plate, a protective film for a display, an OHP film, and a substrate for an electronic material. It can be used in various fields such as films and packaging films.
[0103]
Next, the silver salt photothermographic material of the present invention will be described.
The silver salt photothermographic material is provided with an undercoat layer, an image forming layer containing an organic silver salt, and a protective layer if necessary, on one side of the polyester support, sequentially from the support side. On the other hand, an undercoat layer, a back coat layer and, if necessary, a protective layer are provided on the opposite side of the image forming layer from the support side. The image forming layer refers to a layer containing an organic silver salt, and usually contains a silver halide, a reducing agent, a high contrast agent, and a color tone agent in addition to the organic silver salt.
[0104]
The aqueous composite copolymer dispersion of the present invention is added to any of the above layers. Although not particularly limited, it is preferable to add the compound to the undercoat layer on the image forming layer side or the undercoat layer on the opposite side of the image forming layer from the viewpoint of suppressing antistatic in the process.
[0105]
(Amount of silver applied)
The amount of silver applied to the silver salt photothermographic material is such that the amount of silver per unit volume in the image forming layer after coating and drying and before exposure and thermal development is 1 × 10 5⁴~ 5 × 10⁵g / m³It is. The silver resources corresponding to the silver loading are silver halide grains prepared by reacting the photosensitive silver halide and the organic silver salt with a halogen-containing compound, and converting the aliphatic carboxylic acid silver salt, the aliphatic carboxylic acid salt. It refers to the sum of all silver salt resources such as silver salt.
[0106]
In the present invention, the coating density of silver halide grains having a particle size of 0.01 μm or more (equivalent sphere equivalent diameter) is 1 × 10 5¹⁴~ 1 × 10¹⁸/ M²Is preferable, and 1 × 10^Fifteen~ 1 × 10¹⁷/ M²Is preferred.
[0107]
Further, the coating density of the aliphatic carboxylic acid silver salt is 10 μm or more per silver halide grain having a particle size of 0.01 μm or more (equivalent sphere equivalent particle size).^-17-10^-14g or less, and even 10^-16-10^-15g is preferred.
[0108]
When the coating is performed within the above range, preferable results can be obtained from the viewpoint of the optical maximum density of the silver image per a fixed amount of silver applied, that is, the silver coverage (covering power) and the color tone of the silver image. .
[0109]
(Reducing agent)
The (silver ion) reducing agent used in the present invention is not particularly limited, but a bisphenol derivative represented by the following general formula (A) or (S) is preferably used. In particular, when a compound in which at least one of the reducing agents is a bisphenol derivative is used alone or in combination with another reducing agent having a different chemical structure, performance deterioration due to fogging and the like during storage of the silver salt photothermographic material and heat Color tone deterioration and the like during storage of a silver image after development are unexpectedly suppressed.
[0110]
Embedded image

[0111]
In the general formula (A), the chalcogen atom represented by X is sulfur, selenium, or tellurium, and is preferably a sulfur atom.
[0112]
R represents a hydrogen atom, a halogen atom, an aliphatic group having 7 or less carbon atoms or a cyclic group having 6 or less members, and examples of the halogen atom include fluorine, chlorine, and bromine. Examples of the aliphatic group having 7 or less carbon atoms include methyl, ethyl, propyl, butyl, hexyl, heptyl, vinyl, allyl, butenyl, hexadienyl, ethenyl-2-propenyl, 3-butenyl, and 1-methyl-3-propenyl. , 3-pentenyl, 1-methyl-3-butenyl group and the like. Examples of the 6-membered or less cyclic group include an alicyclic group and a heterocyclic group, and examples of the carbocyclic group include cyclobutene, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, and phenyl. And a 6-membered ring, and a heterocyclic group is preferably a 5- or 6-membered ring group such as pyrazolyl, pyrrolyl, pyrrolidinyl, pyrimidinyl, pyrazyl, pyridyl, triazinyl, thiazolyl, furyl, and pyranyl, and particularly preferably a hydrogen atom or cycloalkyl. A group having a cyclic structure such as an alkyl group, a cycloalkenyl group, and a phenyl group.
[0113]
These groups may further have a substituent, such as a halogen atom (such as fluorine, chlorine, or bromine), a cycloalkyl group (such as cyclohexyl or cycloheptyl), or a cycloalkenyl group (such as 1-cycloalkenyl). Group, 2-cycloalkenyl group, etc.), alkoxy group (methoxy, ethoxy, propoxy, etc.), alkylcarbonyloxy group (acetyloxy, etc.), alkylthio group (methylthio, trifluoromethylthio, etc.), carboxyl group, alkylcarbonylamino group ( Acetylamino, etc.), ureido group (methylaminocarbonylamino, etc.), alkylsulfonylamino group (methanesulfonylamino, etc.), alkylsulfonyl group (methanesulfonyl, trifluoromethanesulfonyl, etc.), carbamoyl group (carbamoyl, N, N-dimethylcarba) Mo , N-morpholinocarbonyl, etc.), sulfamoyl group (sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfamoyl, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group (methane Sulfonamide, butanesulfonamide, etc.), alkylamino group (amino, N, N-dimethylamino, N, N-diethylamino, etc.), sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonylaminocarbonyl group (methane Sulfonylaminocarbonyl, ethanesulfonylaminocarbonyl, etc.), alkylcarbonylaminosulfonyl group (acetamidosulfonyl, methoxyacetamidosulfonyl, etc.), alkynylaminocarbonyl group (acetamidocarbonyl, methoxy) Seto amide carbonyl, etc.), alkylsulfinyl aminocarbonyl group (methanesulfinyl aminocarbonyl include ethanesulfinyl aminocarbonyl, etc.) and the like. When there are two or more substituents, they may be the same or different.
[0114]
R ′ and R ″ each represent a hydrogen atom, a halogen atom or a substituent, and examples of the halogen atom include fluorine, chlorine, and bromine atoms, and examples of the substituent include an alkyl group, an aryl group, and a cycloalkyl group. Group, alkenyl group, cycloalkenyl group, alkynyl group, amino group, acyl group, acyloxy group, acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, sulfonyl group, alkylsulfonyl group, sulfinyl group, cyano group, And a plurality of R ′ and R ″ may be the same or different.
[0115]
R 'preferably has 2 or more carbon atoms. R "preferably has 1 to 5 carbon atoms, more preferably 1 carbon atom. These groups may further have a substituent, and the substituent may be a halogen atom (fluorine, chlorine, bromine, etc.). An alkyl group (methyl, ethyl, propylbutyl, pentyl, i-pentyl, 2-ethyl-hexyl, octyl, decyl, etc.), a cycloalkyl group (cyclohexyl, cycloheptyl, etc.), an alkenyl group (ethenyl-2-propenyl, 3 -Butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, etc.), cycloalkenyl group (1-cycloalkenyl group, 2-cycloalkenyl group, etc.), alkynyl group (ethynyl, 1- Propynyl), alkoxy group (methoxy, ethoxy, propoxy, etc.), alkylcarbonyloxy group (acetyloxy, etc.), Ruthio group (methylthio, trifluoromethylthio etc.), carboxyl group, alkylcarbonylamino group (acetylamino etc.), ureido group (methylaminocarbonylamino etc.), alkylsulfonylamino group (methanesulfonylamino etc.), alkylsulfonyl group (methane A carbamoyl group (carbamoyl, N, N-dimethylcarbamoyl, N-morpholinocarbonyl, etc.), a sulfamoyl group (sulfamoyl, N, N-dimethylsulfamoyl, morpholino sulfamoyl, etc.), trifluoro Methyl group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group (methanesulfonamide, butanesulfonamide, etc.), alkylamino group (amino, N, N-dimethylamino, N, -Diethylamino), sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonylaminocarbonyl group (methanesulfonylaminocarbonyl, ethanesulfonylaminocarbonyl, etc.), alkylcarbonylaminosulfonyl group (acetamidosulfonyl, methoxyacetamidosulfonyl, etc.) Alkynylaminocarbonyl group (acetamidocarbonyl, methoxyacetamidocarbonyl, etc.), alkylsulfinylaminocarbonyl group (methanesulfinylaminocarbonyl, ethanesulfinylaminocarbonyl, etc.).
[0116]
Specific examples of the compound represented by the general formula (A) are shown below.
[0117]
Embedded image

[0118]
Embedded image

[0119]
Embedded image

[0120]
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[0121]
Next, in the general formula (S), Z represents an atomic group necessary for constituting a 3- to 10-membered non-aromatic ring together with a carbon atom. Propyl, aziridyl, oxiranyl, 4-membered ring is cyclobutyl, cyclobutenyl, oxetanyl, azetidinyl, 5-membered ring is cyclopentyl, cyclopentenyl, cyclopentadienyl, tetrahydrofuranyl, pyrrolidinyl, tetrahydrothienyl, 6-membered ring is cyclohexyl, cyclohexyl Hexenyl, cyclohexadienyl, tetrahydropyranyl, pyranyl, piperidinyl, dioxanyl, tetrahydrothiopyranyl, norcaranyl, norpinanyl, norbornyl, cycloheptyl, cycloheptynyl, cycloheptadienyl as the 7-membered ring, and cyclooctyl as the 8-membered ring Nyl, cyclooctenyl, cyclooctadienyl, cyclooctatrienyl, 9-membered ring is cyclononanyl, cyclononenyl, cyclononadienyl, cyclononatrienyl, 10-membered ring is cyclodecanyl, cyclodecenyl, cyclodecadienyl, cyclodecatri Each group such as enyl is exemplified. It is preferably a 3- to 6-membered ring, more preferably a 5- to 6-membered ring, and most preferably a 6-membered ring, and among them, a hydrocarbon ring containing no hetero atom is preferable.
[0122]
The ring may form a spiro bond with another ring through a spiro atom, or may be condensed with another ring including an aromatic ring in any manner. Further, the ring may have an arbitrary substituent. Specific examples of the substituent include a halogen atom (fluorine, chlorine, bromine, etc.), an alkyl group (methyl, ethyl, propyl, butyl, pentyl, i-pentyl, 2-ethyl-hexyl, octyl, decyl, etc.), cycloalkyl Alkyl group (cyclohexyl, cycloheptyl, etc.), alkenyl group (ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, etc.), cycloalkenyl group (1 -Cycloalkenyl group, 2-cycloalkenyl group, etc.), alkynyl group (ethynyl, 1-propynyl, etc.), alkoxy group (methoxy, ethoxy, propoxy, etc.), alkylcarbonyloxy group (acetyloxy, etc.), alkylthio group (methylthio, Trifluoromethylthio, etc.), carboxyl group, alkylcarbonylamido Group (acetylamino, etc.), ureido group (methylaminocarbonylamino, etc.), alkylsulfonylamino group (methanesulfonylamino, etc.), alkylsulfonyl group (methanesulfonyl, trifluoromethanesulfonyl, etc.), carbamoyl group (carbamoyl, N, N- Dimethylcarbamoyl, N-morpholinocarbonyl, etc.), sulfamoyl group (sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfamoyl, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group ( Methanesulfonamide, butanesulfonamide, etc.), alkylamino group (amino, N, N-dimethylamino, N, N-diethylamino, etc.), sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonyl Aminocarbonyl group (methanesulfonylaminocarbonyl, ethanesulfonylaminocarbonyl, etc.), alkylcarbonylaminosulfonyl group (acetamidosulfonyl, methoxyacetamidosulfonyl, etc.), alkynylaminocarbonyl group (acetamidocarbonyl, methoxyacetamidocarbonyl, etc.), alkylsulfinylaminocarbonyl group (Methanesulfinylaminocarbonyl, ethanesulfinylaminocarbonyl, etc.). When there are two or more substituents, they may be the same or different. Particularly preferred substituents are alkyl groups. R₀', R₀"" Represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, but the alkyl group is specifically preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include methyl, ethyl, propyl, i-propyl, Butyl, t-butyl, pentyl, i-pentyl, 2-ethyl-hexyl, octyl, decylcyclohexyl, cycloheptyl, 1-methylcyclohexyl, ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3 -Pentenyl, 1-methyl-3-butenyl, 1-cycloalkenyl, 2-cycloalkenyl, ethynyl, 1-propynyl, etc. More preferably, methyl, ethyl, i-propyl, t-butyl, cyclohexyl, 1- Methyl cyclohexyl, etc., preferably methyl, t-butyl, 1-methylcyclyl Hexyl, most preferably methyl.
[0123]
Specific examples of the aryl group include a phenyl group, a naphthyl group, and an anthranyl group. Specific examples of the heterocyclic group include aromatic heterocyclic groups such as pyridyl, quinolyl, isoquinolyl, imidazolyl, pyrazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, and tetrazolyl, and piperidino, morpholino, tetrahydrofuryl, tetrahydrothienyl, and tetrahydropyranyl. And non-aromatic heterocyclic groups such as
[0124]
These groups may further have a substituent, and examples of the substituent include the same groups as the above-mentioned substituents on the ring. Multiple R₀', R₀"May be the same or different, but most preferably all are methyl groups.
[0125]
Rx represents a hydrogen atom or an alkyl group. Specifically, the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl, i-pentyl, 2-ethyl-hexyl, octyl, decyl, cyclohexyl, cycloheptyl, 1-methylcyclohexyl, ethenyl-2-ethyl Examples include propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, 1-cycloalkenyl group, 2-cycloalkenyl group, ethynyl, 1-propynyl and the like. More preferred are methyl, ethyl, i-propyl and the like. Preferably, Rx is a hydrogen atom.
[0126]
Q₀Represents a group which can be substituted on a benzene ring, and specifically, an alkyl group having 1 to 25 carbon atoms (eg, methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl, cyclohexyl), halogenated Alkyl group (trifluoromethyl, perfluorooctyl, etc.), cycloalkyl group (cyclohexyl, cyclopentyl, etc.), alkynyl group (propargyl, etc.), glycidyl group, acrylate group, methacrylate group, aryl group (phenyl, etc.), heterocyclic group ( Pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, selenazolyl, slipholanyl, piperidinyl, pyrazolyl, tetrazolyl, etc.), halogen atoms (chlorine, bromine, iodine, fluorine, etc.), alkoxy groups (methoxy, ethoxy, Professional Ruoxy, pentyloxy, cyclopentyloxy, hexyloxy, cyclohexyloxy, etc., aryloxy group (phenoxy, etc.), alkoxycarbonyl group (methyloxycarbonyl, ethyloxycarbonyl, butyloxycarbonyl, etc.), aryloxycarbonyl group (phenyloxycarbonyl ), Sulfonamide group (methanesulfonamide, ethanesulfonamide, butanesulfonamide, hexanesulfonamide, cyclohexanesulfonamide, benzenesulfonamide, etc.), sulfamoyl group (aminosulfonyl, methylaminosulfonyl, dimethylaminosulfonyl, butylaminosulfonyl) , Hexylaminosulfonyl, cyclohexylaminosulfonyl, phenylaminosulfonyl, 2-pyridylaminosulfur Yl), urethane group (methyl ureide, ethyl ureide, 2-pyridyl ureide, etc.), acyl group (acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl group (aminocarbonyl, methylaminocarbonyl) , Dimethylaminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, 2-pyridylaminocarbonyl, etc.), amide group (acetamide, propionamide, butanamide, hexanamide, benzamide, etc.), sulfonyl group (methylsulfonyl) , Ethylsulfonyl, butylsulfonyl, cyclohexylsulfonyl, phenylsulfonyl, 2-pyridylsulfonyl, etc.), amino group (amino , Ethylamino, dimethylamino, butylamino, cyclopentylamino, anilino, 2-pyridylamino, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group and the like. These groups may be further substituted with these groups. n and m each represent an integer of 0 to 2, and most preferably n and m are both 0.
[0127]
Hereinafter, specific examples of the compound represented by formula (S) of the present invention will be listed.
[0128]
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[0129]
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[0130]
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[0131]
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[0132]
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[0133]
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[0134]
In the present invention, U.S. Pat. Nos. 3,589,903 and 4,021,249 or British Patent 1,486,148 and JP-A-51-51933, JP-A-50-36110, JP-A-50-116023, Polyphenol compounds described in JP-A-52-84727 or JP-B-51-35727, such as 2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1, Bisnaphthols described in U.S. Pat. No. 3,672,904, such as 1'-binaphthyl, and further, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamide Phenol, 4-benzenesulfonamido naphthol and the like are described in U.S. Pat. It can also be used as a reducing agent, such sulfonamidophenol or sulfonamide naphthols.
[0135]
The amount of the reducing agent including the compounds represented by the general formulas (A) and (S) is preferably 1 × 10 5 per mol of silver.^-2-10 mol, especially 1 × 10^-2１．５1.5 mol.
[0136]
The amount of the reducing agent used in the photothermographic material varies depending on the type of the organic silver salt, the reducing agent, and other additives, but is generally 0.05 to 10 mol, preferably 1 mol, per mol of the organic silver salt. 0.1 to 3 mol is suitable. Within this range, two or more of the above reducing agents may be used in combination. In the present invention, it is sometimes preferable to add and mix a reducing agent to a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt particles and a solvent immediately before coating and to apply the reducing agent because fluctuation in photographic performance due to stagnation time is small. .
[0137]
Two or more of the above reducing agents may be used in combination. In the present invention, it is preferred that the reducing agent is added to a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt particles and a solvent immediately before coating and then mixed and coated. is there.
[0138]
In addition, it is also preferable to use a compound capable of forming a hydrogen bond with hydrogen of a hydroxyl group of the reducing agent, such as triphenylphosphine oxide described in EP 1,096,310, as an auxiliary agent of the reducing agent.
[0139]
(Photosensitive silver halide grains)
The photosensitive silver halide grains (also simply referred to as silver halide grains) used in the silver salt photothermographic material of the present invention will be described. Incidentally, the photosensitive silver halide grains in the present invention can essentially absorb light as an intrinsic property of silver halide crystals, or artificially emit visible light or infrared light by a physicochemical method. When it can be absorbed and absorbs light in any region within the light wavelength range from the ultraviolet region to the infrared region, a physicochemical change occurs in the silver halide crystal and / or on the crystal surface. Refers to silver halide crystal grains that have been processed as possible.
[0140]
The silver halide grains used in the present invention are themselves P.I. Glafkids: Chimie et Physique Photographique (Paul Montel, 1967); F. Duffin: Photographic Emulsion Chemistry (published by The Focal Press, 1966); L. It can be prepared as a silver halide grain emulsion using a method described in Zelikman et al: Making and Coating Photographic Emulsion (published by The Focal Press, 1964).
[0141]
That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt with a soluble halide may be any one of a one-sided mixing method, a double-sided mixing method, a combination thereof and the like. Of these methods, the so-called controlled double jet method of preparing silver halide grains while controlling the formation conditions is preferable among the above methods. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. Or silver iodobromide is preferred. In the case of silver iodobromide, the iodine content is preferably in the range of 0.02 to 6 mol% / Ag1 mol. Even when the iodine content is contained so as to be distributed throughout the silver halide grains, the iodine concentration at a specific portion of the silver halide grains, for example, the iodine concentration at the center of the grain is increased, and the density near the surface is reduced or substantially zero. Such a core / shell type structure may be adopted.
[0142]
Grain formation is usually divided into two stages of silver halide seed grain (nucleus) formation and grain growth, and these methods may be performed continuously at once, or nucleus (seed grain) formation and grain growth may be separated. May be performed. The controlled double jet method of forming particles by controlling the particle formation conditions such as pAg and pH is preferable because the shape and size of the particles can be controlled. For example, when performing a method in which nucleation and grain growth are performed separately, first, a soluble silver salt and a soluble halide are uniformly and rapidly mixed in an aqueous gelatin solution to form nuclei (seed particles) (nucleation step). Thereafter, silver halide grains are prepared by a grain growth step of growing grains while supplying a soluble silver salt and a soluble halide under controlled pAg, pH, and the like. After grain formation, a desired silver halide emulsion can be obtained by removing unnecessary salts and the like by a desalting step by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method. I can do it.
[0143]
The silver halide grains used in the present invention are preferably mixed with those having different grain diameters, and the average grain size is 0.040 μm or less when the grains having a size smaller than 0.02 μm are excluded from the measurement. Alternatively, the number of silver halide grains of 0.070 to 0.100 μm is preferably in the range of 10 to 30% of the whole. When the silver halide grains are cubic or octahedral, that is, so-called normal crystals, the grain size refers to the length of the edge of the silver halide grains. In the case where the silver halide grains are tabular grains, the diameter refers to the diameter when converted into a circular image having the same area as the projected area of the main surface.
[0144]
The silver halide grains are preferably monodispersed. The term “monodisperse” as used herein means that the coefficient of variation of the particle diameter determined by the following equation is 30% or less. It is preferably at most 20%, more preferably at most 15%.
[0145]
Coefficient of variation of particle size% = (standard deviation of particle size / average value of particle size) × 100
Examples of the shape of silver halide grains include cubic, octahedral, and tetrahedral grains, tabular grains, spherical grains, rod-like grains, potato-like grains, and among them, cubic, octahedral, and tetrahedral grains are particularly preferred. And tabular silver halide grains are preferred.
[0146]
When tabular silver halide grains are used, the average aspect ratio is preferably 1.5 to 100, more preferably 2 to 50 or less. These are described in U.S. Pat. Nos. 5,264,337, 5,314,798, and 5,320,958, and can easily obtain target tabular grains. Further, grains having rounded corners of silver halide grains can also be preferably used.
[0147]
The crystal habit on the outer surface of the silver halide grains is not particularly limited. However, in the case of using a spectral sensitizing dye having crystal habit (plane) selectivity in the adsorption reaction of the sensitizing dye on the surface of the silver halide grains. It is preferable to use silver halide grains having a relatively high proportion of crystal habit adapted to the selectivity. For example, when a sensitizing dye that selectively adsorbs to a crystal plane having a Miller index of [100] is used, the ratio of the [100] plane to the outer surface of the silver halide grain is preferably high, and this ratio is preferably 50%. %, More preferably 70% or more, particularly preferably 80% or more. Incidentally, the ratio of the Miller index [100] plane is determined by the T.V. method using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging Sci. , 29, 165 (1985).
[0148]
The silver halide grains used in the present invention are preferably prepared at the time of grain formation using low molecular weight gelatin having an average molecular weight of 50,000 or less, and particularly preferably used at the time of nucleation of silver halide grains. The low molecular weight gelatin has an average molecular weight of 50,000 or less, preferably 2,000 to 40,000, and more preferably 5,000 to 25,000. The average molecular weight of gelatin can be measured by gel filtration chromatography. Low-molecular-weight gelatin is generally used for enzymatic degradation by adding a gelatin-degrading enzyme to an aqueous gelatin solution having an average molecular weight of about 100,000, hydrolyzing by adding an acid or alkali, and heating under atmospheric pressure or under pressure. By thermal decomposition, decomposition by irradiation with ultrasonic waves, or a combination of these methods.
[0149]
The concentration of the dispersion medium at the time of nucleation is preferably 5% by mass or less, and it is more effective to carry out the concentration at a low concentration of 0.05 to 3.0% by mass.
[0150]
As the silver halide grains, it is preferable to use a polyethylene oxide compound represented by the following general formula (AO) when forming the grains.
[0151]
General formula (AO)
YO (CH₂CH₂O)_m(CH (CH₃) CH₂O)_p(CH₂CH₂O)_nY
Wherein Y is a hydrogen atom, -SO₃M represents -CO-B-COOM, M represents a hydrogen atom, an alkali metal atom, an ammonium group or an ammonium group substituted with an alkyl group having 5 or less carbon atoms, and B represents an organic dibasic acid. It represents a chain or cyclic group to be formed. m and n each represent 0 to 50, and p represents 1 to 100.
[0152]
The above polyethylene oxide compound is used for producing a silver halide photographic light-sensitive material, a step of producing an aqueous gelatin solution, a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution, and a step of coating the emulsion on a support. And the like, which has been preferably used as an antifoaming agent against remarkable foaming when the emulsion raw materials are stirred or moved, and the technique used as an antifoaming agent is described in, for example, JP-A-44-9497. Have been. The polyethylene oxide compound also functions as a defoaming agent during nucleation.
[0153]
The polyethylene oxide compound is preferably used in an amount of 1% by mass or less based on silver, more preferably 0.01 to 0.1% by mass.
[0154]
The polyethylene oxide compound of the above general formula (AO) only needs to be present at the time of nucleation, and is preferably added in advance to the dispersion medium before nucleation, but may be added during nucleation. It may be added to a silver salt aqueous solution or a halide aqueous solution used for formation. Preferably, it is used by adding to the aqueous halide solution or both aqueous solutions at 0.01 to 2.0% by mass. Also, it is preferable to exist for at least 50% of the time of the nucleation step, and more preferably for at least 70% of the time. The polyethylene oxide compound may be added in the form of a powder or dissolved in a solvent such as methanol.
[0155]
The temperature at the time of nucleation is 5 to 60 ° C., preferably 15 to 50 ° C. Even if the temperature is constant, the temperature rising pattern (the temperature at the start of nucleation is 25 ° C. In the case where the temperature at the end of nucleation is 40 ° C.) or the reverse pattern, it is preferable to control within the above temperature range.
[0156]
The concentration of the silver salt aqueous solution and the halide aqueous solution used for nucleation is preferably 3.5 mol (mol) / L (liter) or less, and more preferably used in a low concentration range of 0.01 to 2.5 mol / L. . The rate of silver ion addition during nucleation is 1.5 × 10^-3~ 3.0 × 10^-1Mol / min is preferred, and more preferably 3.0 × 10^-3~ 8.0 × 10^-2Mol / min.
[0157]
The pH at the time of nucleation can be set in the range of 1.7 to 10, but the pH at the alkali side is preferably pH 2 to 6 to broaden the particle size distribution of nuclei to be formed. Further, pBr at the time of nucleation is about 0.05 to 3.0, preferably 1.0 to 2.5, and more preferably 1.5 to 2.0.
[0158]
It is preferred from the viewpoint of sensitivity and image storability that a heterocyclic compound is contained inside the silver halide grains after nucleation. Examples of the heterocyclic compound used herein include imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, and cinnoline. , Pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, indolenine, tetrazaindene and the like, preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, Thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, shinno Emissions, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, a tetrazaindene and the like.
[0159]
Note that the above heterocyclic compound may have a substituent, and the substituent is preferably an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group, an acyloxy group, an acyl group, an alkoxycarbonyl group, an aryl group. Oxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, sulfonyl group, ureido group, phosphoric amide group, halogen atom, cyano group, sulfo group A carboxyl group, a nitro group, a heterocyclic group, more preferably an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, Rufamoyl group, carbamoyl group, ureido group, phosphoramide group, halogen atom, cyano group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy group, acyl group, acylamino group, A sulfonylamino group, a sulfamoyl group, a carbamoyl group, a halogen atom, a cyano group, a nitro group, and a heterocyclic group.
[0160]
The silver halide grains may be added to the image forming layer (photosensitive layer) by any method. At this time, the silver halide grains are arranged so as to be close to a reducible silver source (silver aliphatic carboxylate). Is preferred.
[0161]
The silver halide is prepared in advance, and it is added to a solution for preparing the silver aliphatic carboxylate particles, and the silver halide preparing step and the aliphatic carboxylic acid silver salt particle preparing step are separated. Although it is preferable from the viewpoint of production control because it can be handled, as described in British Patent 1,447,454, a halogen component such as a halide ion is used to prepare a silver salt of an aliphatic carboxylic acid when preparing silver particles of an aliphatic carboxylic acid. By coexisting with a forming component and injecting silver ions into the mixture, it is possible to form silver aliphatic carboxylate particles almost simultaneously with the generation thereof. It is also possible to prepare a silver halide grain by converting a silver salt of an aliphatic carboxylic acid with a halogen-containing compound by reacting the compound with a halogen. That is, a silver halide-forming component is allowed to act on a previously prepared solution or dispersion of a silver salt of an aliphatic carboxylic acid, or a sheet material containing the silver salt of an aliphatic carboxylic acid, to thereby form a part of the silver salt of an aliphatic carboxylic acid. It can also be converted to photosensitive silver halide.
[0162]
However, the photosensitive silver halide grains of the present invention refer to silver halide grains that have been prepared in advance separately from the silver salt of a fatty carboxylic acid, without directly relating to the silver salt of a fatty acid.
[0163]
Examples of silver halide grain forming components include inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds, and specific examples thereof are described in US Pat. No. 4,009,039. No. 3,457,075, No. 4,003,749, British Patent No. 1,498,956 and JP-A Nos. 53-27027 and 53-25420, metal halides, ammonium halides and the like. Onium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide and trimethylbenzylammonium bromide, and halogenated carbonized compounds such as iodoform, bromoform, carbon tetrachloride and 2-bromo-2-methylpropane. Hydrogens, N-bromoamber Imide, N- bromo phthalimide, N- halogen compounds such as N- bromoacetamide, other, for example triphenylmethyl chloride, bromide triphenylmethyl, 2-bromoacetic acid, 2-bromo ethanol, dichloro benzophenone. Thus, the silver halide can be prepared by converting a part or all of the silver in the organic acid silver salt to silver halide by reacting the organic acid silver with the halide ion. Further, silver halide grains produced by converting a part of the aliphatic carboxylic acid silver salt to separately prepared silver halide may be used in combination.
[0164]
These silver halide grains, separately prepared silver halide grains, silver halide grains obtained by conversion of aliphatic carboxylic acid silver salt, 0.001 to 0.7 mole per mole of aliphatic carboxylic acid silver salt, Preferably, 0.03 to 0.5 mol is used.
[0165]
The silver halide grains preferably contain ions of a transition metal belonging to Groups 6 to 11 of the periodic table. As the above metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable. These may be used alone or in combination of two or more of the same or different metal complexes. These metal ions may be directly introduced into silver halide as a metal salt, but can be introduced into silver halide in the form of a metal complex or complex ion. The preferred content is 1 × 10^-9~ 1 × 10^-2The molar range is preferably 1 × 10^-8~ 1 × 10^-4Is more preferable. The transition metal complex or complex ion is preferably represented by the following general formula.
[0166]
General formula [ML₆]^m
In the formula, M is a transition metal selected from elements of Groups 6 to 11 of the periodic table, and particularly, Os and Ru are preferable. L represents a ligand, and m represents 0,-, 2-, 3- or 4-. Specific examples of the ligand represented by L include halogen ions (fluorine, chlorine, bromine, and iodide ions), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo ligands, Examples include nitrosyl, thionitrosyl and the like, and preferred are aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.
[0167]
The compound which provides the ion or complex ion of these metals is preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, and physical ripening It may be added at any stage before and after chemical sensitization, but is particularly preferably added at the stage of nucleation, growth, and physical ripening, more preferably at the stage of nucleation and growth. Preferably, it is added at the stage of nucleation. In the addition, it may be added in several portions, may be added uniformly in the silver halide grains, or may be added uniformly to the silver halide grains, as disclosed in JP-A-63-29603, JP-A-2-306236 and JP-A-2-306236. As described in JP-A-167545, JP-A-4-76534, JP-A-6-110146, JP-A-5-273683 and the like, the particles can be contained in the particles with a distribution.
[0168]
These metal compounds can be added by dissolving them in water or a suitable organic solvent (alcohols, ethers, glycols, ketones, esters, amides). For example, an aqueous solution of a metal compound powder or A method in which an aqueous solution in which a metal compound and sodium chloride and potassium chloride are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are mixed at the same time. At the same time, a method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of charging a required amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or a method of mixing silver halides During preparation, there is a method in which another silver halide grain doped with metal ions or complex ions in advance is added and dissolved. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and sodium chloride and potassium chloride are dissolved together is added to a water-soluble halide solution. When adding to the surface of the particles, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.
[0169]
The separately prepared photosensitive silver halide grains can be desalted by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method. it can.
[0170]
In the present invention, the grain size of the silver halide grains can be arbitrarily controlled by a method known in the photographic art, such as changing the temperature and the growth time during growth after nucleation.
[0171]
(Silver aliphatic carboxylate)
The aliphatic carboxylic acid silver salt is a reducible silver source, and is preferably a silver salt of an aliphatic carboxylic acid having 10 to 30 carbon atoms, preferably 15 to 25 carbon atoms. Examples of suitable silver salts include the following.
[0172]
Silver salts such as gallic acid, oxalic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Among them, preferred silver salts include silver behenate, silver arachidate and silver stearate. In the present invention, it is preferable that two or more kinds of aliphatic carboxylic acid silver salts are mixed in order to improve developability and to form a high-density, high-contrast silver image. The silver ion solution is preferably prepared by mixing the acid mixture with a silver ion solution, and the molar ratio of silver behenate is preferably 80% or more.
[0173]
The aliphatic carboxylic acid silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and is described in a forward mixing method, a reverse mixing method, a simultaneous mixing method, and JP-A No. 9-127643. A controlled double jet method or the like is preferably used. For example, an organic acid alkali metal salt soap (sodium behenate, sodium arachidate, etc.) is prepared by adding an alkali metal salt (sodium hydroxide, potassium hydroxide, etc.) to an organic acid, and then controlled by a controlled double jet method. A soap and silver nitrate are mixed to prepare a crystal of a silver salt of an aliphatic carboxylic acid. At that time, silver halide grains may be mixed.
[0174]
In the aliphatic carboxylic acid silver salt, the average equivalent circle diameter is 0.05 to 0.8 μm, and the average thickness is preferably 0.005 to 0.07 μm, and particularly preferably the average equivalent circle diameter is 0 μm. 0.2 to 0.5 μm and an average thickness of 0.01 to 0.05 μm. When the average equivalent circle diameter is less than 0.05 μm, transparency is excellent, but the image storability is poor. When the average equivalent circle diameter exceeds 0.8 μm, devitrification is severe. When the average thickness is less than 0.005 μm, the surface area is large and silver ions are rapidly supplied during development. Especially in a low density portion, a large amount of silver ions remain in the film without being used for a silver image. In addition, the image storability deteriorates significantly. When the average thickness exceeds 0.07 μm, the surface area is reduced and the image stability is improved, but the silver supply during development is slow, and the developed silver shape becomes non-uniform, especially in the high-density portion, and as a result the maximum density is increased. Easy to get low.
[0175]
In order to determine the average equivalent circle diameter, the silver salt of aliphatic carboxylic acid after dispersion is diluted and dispersed on a grid with a carbon support film, and is measured by a transmission electron microscope (manufactured by JEOL Ltd .: 2000FX type) at a direct magnification of 5,000. Photographed at 2x. The negative is captured as a digital image by a scanner, and the average particle diameter is calculated by measuring 300 or more particle diameters (equivalent circle diameter) using appropriate image processing software.
[0176]
The average thickness is calculated by a method using a TEM (transmission electron microscope) as shown below.
[0177]
First, the image forming layer applied on the support is attached to an appropriate holder with an adhesive, and an ultra-thin section having a thickness of 0.1 to 0.2 μm is prepared using a diamond knife in a direction perpendicular to the surface of the support. I do. The produced ultrathin section was supported on a copper mesh, transferred onto a carbon film that had been hydrophilized by glow discharge, and cooled to −130 ° C. or lower with liquid nitrogen, while using a TEM at a magnification of 5,000 to 40,000. Observe the bright field image at 000x and record the image quickly on a film, imaging plate, CCD camera or the like. At this time, as the visual field to be observed, it is preferable to appropriately select a portion where there is no break or looseness in the section.
[0178]
It is preferable to use a carbon film supported by an organic film such as an extremely thin collodion or formvar, and more preferably to be formed on a rock salt substrate and obtained by dissolving and removing the substrate, or to form the organic film as an organic film. This is a film of carbon alone obtained by removing the solvent and ion etching. The acceleration voltage of the TEM is preferably from 80 to 400 kV, particularly preferably from 80 to 200 kV.
[0179]
For more information on electron microscopy techniques and sample preparation techniques, see "The Electron Microscopy Society of Japan, Kanto Chapter / Medical and Biological Electron Microscopy" (Maruzen), "The Japan Electron Microscopy Society, Kanto Chapter", Electron Microscopy Biological Specimens Production method ”(Maruzen) can be referred to.
[0180]
Regarding the TEM image recorded on an appropriate medium, it is preferable that one image is decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing is performed by a computer. In order to perform image processing, it is preferable that an analog image recorded on a film is converted into a digital image by a scanner or the like, and shading correction, contrast / edge enhancement, and the like are performed as necessary. Thereafter, a histogram is prepared, and a portion corresponding to silver aliphatic carboxylate is extracted by binarization.
[0181]
The thickness of the extracted aliphatic carboxylic acid silver salt particles is manually measured with 300 or more suitable software, and the average value is determined.
[0182]
The method for obtaining the silver aliphatic carboxylate particles having the above-mentioned shape is not particularly limited, but the mixed state at the time of forming the organic acid alkali metal salt soap and / or the mixed state at the time of adding silver nitrate to the soap is excellent. It is effective to keep the ratio, optimize the ratio of the organic acid to the soap, and the ratio of the silver nitrate reacting with the soap.
[0183]
The silver aliphatic carboxylate particles of the present invention (referred to silver aliphatic carboxylate particles having an average equivalent circle diameter of 0.05 to 0.8 μm and an average thickness of 0.005 to 0.07 μm) It is preferable that after preliminarily dispersing together with a binder or a surfactant, if necessary, the mixture is dispersed and pulverized by a media disperser or a high-pressure homogenizer. For the preliminary dispersion, a general stirrer such as an anchor type or a propeller type, a high-speed rotation centrifugal radiation type stirrer (dissolver), and a high-speed rotation shear type stirrer (homomixer) can be used.
[0184]
Further, as the media dispersing machine, a ball mill, a planetary ball mill, a rolling mill such as a vibrating ball mill, a bead mill as a medium stirring mill, an attritor, and other basket mills can be used. As the high-pressure homogenizer, a wall mill can be used. Various types can be used, such as a type that collides with a plug or the like, a type in which liquids are divided into a plurality of pieces and then collides with each other at high speed, and a type that passes through a thin orifice.
[0185]
As ceramics used for ceramic beads used at the time of media dispersion, for example, Al₂O₃, BaTiO₃, SrTiO₃, MgO, ZrO, BeO, Cr₂O₃, SiO₂, SiO₂-Al₂O₃, Cr₂O₃-MgO, MgO-CaO, MgO-C, MgO-Al₂O₃(Spinel), SiC, TiO₂, K₂O, Na₂O, BaO, PbO, B₂O₃, SrTiO₃(Strontium titanate), BeAl₂O₄, Y₃Al₅O₁₂, ZrO₂-Y₂O₃(Cubic zirconia), 3BeO-Al₂O₃-6SiO₂(Synthetic emerald), C (synthetic diamond), Si₂On-nH₂O, silicon nitride, yttrium stabilized zirconia, zirconia reinforced alumina and the like are preferred. Yttrium-stabilized zirconia and zirconia reinforced alumina (these ceramics containing zirconia are hereinafter abbreviated as zirconia) are particularly preferably used because impurities generated due to friction with beads and a disperser during dispersion are small.
[0186]
In the apparatus used for dispersing the silver aliphatic carboxylate particles of the present invention, zirconia, alumina, silicon nitride, ceramics such as boron nitride, etc. It is preferable to use diamond, and particularly preferable to use zirconia.
[0187]
When performing the above dispersion, the binder concentration is preferably 0.1 to 10% of the mass of the aliphatic silver carboxylate, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion to the main dispersion. Preferred operating conditions for the main dispersion include, for example, when a high-pressure homogenizer is used as the dispersing means, 29.42 to 98.06 MPa, and the number of operations is preferably two or more. When a media dispersing machine is used as the dispersing means, a preferable condition is a peripheral speed of 6 to 13 m / sec.
[0188]
The compound that functions as a crystal growth inhibitor or dispersant for the silver aliphatic carboxylate particles refers to the step of producing the silver aliphatic carboxylate under the conditions in which the compound is present in the step of producing the silver aliphatic carboxylate particles. A compound having a function and an effect of reducing the particle size and monodispersing when produced under the condition that coexistence does not occur. Specific examples include monohydric alcohols having 10 or less carbon atoms, preferably secondary alcohols, tertiary alcohols, glycols such as ethylene glycol and propylene glycol, polyethers such as polyethylene glycol, and glycerin. The preferable addition amount is 10 to 200% by mass based on the aliphatic silver carboxylate.
[0189]
On the other hand, i-heptanoic acid, i-decanoic acid, i-tridecanoic acid, i-myristic acid, i-palmitic acid, i-stearic acid, i-arachidic acid, i-behenic acid, i-hexanoic acid, etc. Branched aliphatic carboxylic acids containing isomers are also preferred. In this case, a preferable side chain is an alkyl group or alkenyl group having 4 or less carbon atoms. Also, aliphatic unsaturated carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, moloctic acid, eicosenoic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, and seracolenic acid. Can be The preferred addition amount is 0.5 to 10 mol% of the silver aliphatic carboxylate.
[0190]
Glycosides such as glucoside, galactoside, and fructoside; trehalose-type disaccharides such as trehalose and sucrose; polysaccharides such as glycogen, dextrin, dextran, and alginic acid; cellosolves such as methyl cellosolve and ethyl cellosolve; , Methyl acetate, dimethylformamide and other water-soluble organic solvents, polyvinyl alcohol, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone, gelatin, etc. Polymers are also preferred compounds. The preferable addition amount of these is 0.1 to 20% by mass with respect to the aliphatic silver carboxylate.
[0191]
Alcohols having 10 or less carbon atoms, preferably secondary or tertiary alcohols, are reduced in viscosity by increasing the solubility of sodium aliphatic carboxylate in the charging step, and are monodispersed and reduced by increasing the stirring efficiency. Particle size. Branched aliphatic carboxylic acids and aliphatic unsaturated carboxylic acids have higher steric hindrance than silver aliphatic carboxylate, which is the main component when silver aliphatic carboxylate is crystallized, and disorder of the crystal lattice is large. As a result, large crystals are not generated, and as a result, the particle size is reduced.
[0192]
As described above, the biggest difference in the composition of the silver halide photothermographic material compared to the conventional silver halide photographic light-sensitive material is that the latter material has a fog or A large amount of a photosensitive silver halide, an organic silver salt, and a reducing agent, which may cause generation of printout silver (printed silver). For this reason, silver salt photothermographic materials require advanced fog prevention and image stabilization techniques in order to maintain storage stability not only before development but also after development. Mercury compounds such as mercury acetate, which has the function of oxidizing and eliminating fog nuclei, have been used as very effective storage stabilizers in addition to aromatic heterocyclic compounds that suppress development. The use of the compound was problematic in terms of safety and environmental conservation.
[0193]
(Toning agent)
It is desirable to use a toning agent in the silver salt photothermographic material. Examples of suitable toning agents are described in Research Disclosure (RD) 17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136 and 4,021,249. Disclosed, for example, include:
[0194]
Imides (succinimide, phthalimide, naphthalimide, N-hydroxy-1,8-naphthalimide and the like); mercaptans (3-mercapto-1,2,4-triazole and the like); phthalazinone derivatives or metal salts of these derivatives (phthalazinone, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, 2,3-dihydro-1,4-phthalazinedione and the like; phthalazine and phthalic acids (phthalic acid, 4 -Methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic acid, etc.); phthalazine and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivative and its anhydride (phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic anhydride The combination and the like with at least one compound selected from the like). Particularly preferred toning agents are phthalazinone or a combination of phthalazine and phthalic acids and phthalic anhydrides.
[0195]
Particularly in the present invention, carboxylic acids such as phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic anhydride, benzoic acid, 4-methylbenzoic acid, 4-nitrobenzoic acid and pentachlorobenzoic acid are used. The compound to be contained is preferably contained in a non-image forming layer adjacent to the image forming layer. More preferably, it is contained in the non-image forming layer on the side opposite to the support with respect to the image forming layer.
[0196]
The addition amount of the compound having a carboxylic acid group of the present invention contained in the non-image forming layer is preferably 0.005 to 0.20 mol, more preferably 0.01 to 0.10 mol per mol of silver. Is a mole.
[0197]
Conventionally, regarding the color tone of an output image for medical diagnosis, it is said that a cold tone image tone makes it easier for a reader of an X-ray photograph to obtain a more accurate diagnosis and observation result of a recorded image. Here, the cool image tone is a pure black tone or a blue-black tone in which a black image is bluish, and the warm image tone is a warm black tone in which a black image is brownish. Say
[0198]
The terms “cooler” and “warmer” regarding the color tone are determined by the hue angle “hab” at the minimum density Dmin and the optical density D = 1.0. The hue angle hab is a color space having a perceptually nearly equal rate recommended by the International Commission on Illumination (CIE) in 1976.^*a^*b^*Color coordinate a of color space^*, B^*Is calculated using the following equation.
[0199]
hab = tan^-1(B^*/ A^*)
A preferred hab range is 180 ° <hab <270 °, more preferably 200 ° <hab <270 °, and most preferably 220 ° <hab <260 °.
[0200]
(Anti-fogging and image stabilizer)
In silver salt photothermographic materials, as a reducing agent, a reducing agent of bisphenols is mainly used as described below, so that the reducing agent is inactivated by generating active species capable of extracting these hydrogens. It is preferable that the compound contains a compound which can be converted into a compound. It is preferably a compound capable of generating free radicals as reactive species when exposed to light as a colorless photo-oxidizable substance.
[0201]
Accordingly, any compound having these functions may be used, but an organic free radical consisting of a plurality of atoms is preferable. A compound having any structure may be used as long as it has such a function and does not cause any particular adverse effect on the silver salt photothermographic material. Compounds that generate these free radicals may be carbocyclic or heterocyclic in order to provide stability such that the generated free radicals can be contacted for a sufficient time to react with and inactivate the reducing agent. Those having an aromatic group of the formula are preferred.
[0202]
Representative examples of these compounds include the following biimidazolyl compounds and iodonium compounds. For example, a biimidazolyl compound can be produced by the production method described in US Pat. No. 3,734,733 and British Patent 1,271,177 and a method analogous thereto. Preferred specific examples include, for example, compound examples described in JP-A-2000-321711.
[0203]
Similarly, suitable compounds include iodonium compounds. Iodonium compounds are described in Org. Syn. , 1961 and by Fieser: Advanced Organic Chemistry (Reinhold, NY, 1961) and a method analogous thereto. Preferred specific examples include, for example, compound examples described in JP-A-2000-321711.
[0204]
The addition amount of these compounds is 10^-3-10^-1Mol / m², Preferably 5 × 10^-3~ 5 × 10^-2Mol / m²It is. The compound can be contained in any of the constituent layers of the light-sensitive material of the present invention, but is preferably contained in the vicinity of a reducing agent.
[0205]
As the compound that inactivates the reducing agent and prevents the reducing agent from reducing the silver salt of the aliphatic carboxylic acid to silver, it is preferable that the reactive species is not a halogen atom, but the halogen atom is released as an active species. Compounds can also be used in combination with compounds that release active species that are not halogen atoms. Many compounds that can release a halogen atom as an active species are known, and a good effect can be obtained when used in combination.
[0206]
Specific examples of the compounds that generate these active halogen atoms include 4-1 to 4-64 described in JP-A-2001-249428.
[0207]
The addition amount of these compounds is preferably within a range in which the increase in printout silver due to the formation of silver halide does not cause a problem, and is preferably at most 150% or less, more preferably 100% or less, based on the compound that does not generate active halogen radicals. % Is desirable.
[0208]
In addition, in addition to the above compounds, the silver salt photothermographic material may contain a compound conventionally known as an antifoggant, but a compound capable of producing the same reactive species as the above compound. Or a compound having a different antifogging mechanism. For example, U.S. Pat. Nos. 3,589,903, 4,546,075, 4,452,885, JP-A-59-57234, U.S. Pat. Nos. 3,874,946 and 4,756,999. And compounds described in JP-A-9-288328 and JP-A-9-90550. Further, other antifoggants include the compounds disclosed in U.S. Pat. No. 5,028,523 and European Patents 600,587, 605,981 and 631,176.
[0209]
It is preferable to use a thiosulfonic acid compound represented by the following general formula (B) in combination as long as the effects of the present invention are not impaired.
[0210]
General formula (B) R-SO₂SM
In the formula, R may be the same or different and represents an aliphatic group, an aromatic group or a heterocyclic group, and M represents a cation.
[0211]
When R is an aliphatic group, it is preferably an alkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, or an alkynyl group, and these may have a substituent. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, i-propyl, t-butyl and the like.
[0212]
Examples of the anenyl group include allyl and butenyl.
Examples of the alkynyl group include propargyl and butynyl.
[0213]
When R is an aromatic group, it preferably has 6 to 20 carbon atoms, such as phenyl and naphthyl. These may be substituted.
[0214]
When R is a heterocyclic group, a 3- to 15-membered ring having at least one element selected from nitrogen, oxygen, sulfur, selenium, and tellurium is preferable, for example, pyrrolidinyl, piperidinyl, pyridyl, tetrahydrofuranyl, thienyl, oxazolyl, Examples thereof include thiazolyl, imidazolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, selenazolyl, benzoselenazolyl, tellrazolyl, triazolyl, benzotriazolyl, oxadiazolyl, and thiadiazolyl.
[0215]
Examples of the substituent of R include an alkyl group (eg, methyl, ethyl, hexyl), an alkoxy group (eg, methoxy, ethoxy, octyl), an aryl group (eg, phenyl, naphthyl, tolyl), a hydroxyl group, and a halogen atom (eg, fluorine, chlorine). , Bromine, iodine), aryloxy group (phenoxy, etc.), alkylthio group (methylthio, butylthio, etc.), arylthio group (phenylthio, etc.), acyl group (acetyl, propionyl, butyryl, valeryl, etc.), sulfonyl group (methylsulfonyl, phenyl) Sulfonyl, etc.), acylamino group (acetylamino, benzamino, etc.), sulfonylamino group (methanesulfonylamino, benzenesulfonylamino, etc.), acyloxy group (acetoxy, benzoxy, etc.), carboxyl group, cyano group, sulfo group, amino group. Can be
[0216]
M is preferably a metal ion or an organic cation. Examples of the metal ion include a lithium ion, a sodium ion, and a potassium ion. Examples of the organic cation include an ammonium ion (animonium, tetramethylammonium, tetrabutylammonium, etc.), a phosphonium ion (tetraphenylphosphonium, etc.), and a guanidyl group.
[0217]
The compound represented by formula (B) can be added to the emulsion at any time during the formation of silver salt grains, before or after chemical ripening, or immediately before coating. The preferred timing of addition is from after chemical sensitization or spectral sensitization to immediately before coating. A preferable addition amount is 1 × 10 5 per mol of silver.^-5~ 1 mol, more preferably 1 × 10^-3１1 × 0.1 mol.
[0218]
(Chemical sensitization)
For example, according to the methods described in JP-A-2001-249426 and JP-A-2001-249428, the use of a compound that releases a chalcogen such as sulfur, selenium, or tellurium or a noble metal compound that releases a noble metal ion such as a gold ion enables chemical reaction. A sensitizing center (chemical sensitizing nucleus) can be formed and provided. In particular, chemical sensitization with an organic sensitizer containing a chalcogen atom is preferred.
[0219]
The organic sensitizer containing a chalcogen atom is preferably a compound having a group capable of adsorbing to silver halide and a site of an unstable chalcogen atom. As these organic sensitizers, organic sensitizers having various structures disclosed in JP-A-60-150046, JP-A-4-109240 and JP-A-11-218874 can be used. Among them, it is preferable to use at least one compound having a structure in which a chalcogen atom is bonded to a carbon atom or a phosphorus atom by a double bond.
[0220]
The amount of the chalcogen compound used as the organic sensitizer varies depending on the chalcogen compound to be used, silver halide grains, the reaction environment for chemical sensitization, and the like.^-8-10^-2Mol is preferred, more preferably 10^-7-10^-3Use moles. There is no particular limitation on the chemical sensitization environment, but in the presence of a compound capable of eliminating silver chalcogenide or silver nuclei on the photosensitive silver halide grains or reducing the size thereof, and particularly in the presence of silver nuclei. In the presence of an oxidizing agent which can be oxidized, sensitization is preferably performed using an organic sensitizer containing a chalcogen atom. As the sensitizing condition, pAg is preferably 6 to 11, more preferably 7 to 10 The pH is preferably 4 to 10, more preferably 5 to 8, and the temperature is preferably 30 ° C. or less.
[0221]
Therefore, in the silver salt photothermographic material of the present invention, in the presence of an oxidizing agent capable of oxidizing silver nuclei on the grains of the photosensitive silver halide, using an organic sensitizer containing a chalcogen atom, It is preferable to use a photosensitive emulsion which has been subjected to chemical sensitization at a temperature of 30 ° C. or lower, mixed with a silver salt of an aliphatic carboxylic acid, dispersed, dehydrated and dried.
[0222]
The chemical sensitization using these organic sensitizers is preferably carried out in the presence of a heteroatom-containing compound having adsorptivity to spectral sensitizing dyes or silver halide grains. By performing chemical sensitization in the presence of a compound having an adsorptivity to silver halide, dispersion of the chemical sensitization center nucleus can be prevented, and high sensitivity and low fog can be achieved. Although the spectral sensitizing dye will be described later, the heteroatom-containing compound having adsorptivity to silver halide is preferably a nitrogen-containing heterocyclic compound described in JP-A-3-24537. In the nitrogen-containing heterocyclic compound, the heterocyclic ring is a pyrazole ring, a pyrimidine ring, a 1,2,4-triazole ring, a 1,2,3-triazole ring, a 1,3,4-thiadiazole ring, a 1,2,3- A thiadiazole ring, a 1,2,4-thiadiazole ring, a 1,2,5-thiadiazole ring, a 1,2,3,4-tetrazole ring, a pyridazine ring, a 1,2,3-triazine ring; Examples thereof include three bonded rings, such as a triazolotriazole ring, a diazaindene ring, a triazaindene ring, and a pentaazaindene ring. A condensed heterocyclic ring of a monocyclic heterocycle and an aromatic ring, for example, a phthalazine ring, a benzimidazole ring, an indazole ring, a benzthiazole ring, and the like can also be applied.
[0223]
Of these, an azaindene ring is preferable, and an azaindene compound having a hydroxyl group as a substituent, such as a hydroxytriazaindene, hydroxytetrazaindene, or hydroxypentazaindene compound, is more preferable. The heterocyclic ring may have a substituent other than the hydroxyl group. Examples of the substituent include (substituted) alkyl, alkylthio, amino, hydroxyamino, alkylamino, dialkylamino, arylamino, carboxyl, alkoxycarbonyl, halogen, and cyano groups. .
[0224]
The addition amount of the heterocyclic compound may vary over a wide range depending on the size, composition, and other conditions of the silver halide grains.^-6To 1.0 mole, preferably 10 moles.^-4-10^-1Range of moles.
[0225]
Noble metal sensitization can be applied to the photosensitive silver halide using a compound that releases a noble metal ion such as a gold ion. For example, chloroaurate or an organic gold compound can be used as a gold sensitizer.
[0226]
In addition to the above sensitization methods, reduction sensitization methods and the like can also be used. Examples of the shell-like compounds for reduction sensitization include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, and borane compounds. , A silane compound, a polyamine compound, and the like. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less.
[0227]
The silver halide subjected to chemical sensitization may be formed in the presence of an organic silver salt, may be formed in the absence of an organic silver salt, or may be formed under a mixed condition of both. It may be formed.
[0228]
(Spectral sensitization)
It is preferred that a spectral sensitizing dye is adsorbed on the photosensitive silver halide grains to perform spectral sensitization. As the spectral sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. For example, JP-A-63-159814, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, JP-A-63-15245, U.S. Pat. Nos. 4,639,414, and 4 , 740,455, 4,741,966, 4,751,175, and 4,835,096. Useful sensitizing dyes are described, for example, in the documents described or cited in RD17643, page 23, section IV-A (December 1978) and 18431, 437, section X (August 1978). . In particular, it is preferable to use a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers and scanners. For example, compounds described in JP-A-9-34078, JP-A-9-54409, and JP-A-9-80679 are preferable.
[0229]
Useful cyanine dyes are cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolinedione nucleus, a barbituric acid nucleus, a thiazolinone nucleus, a malononitrile nucleus and a pyrazolone nucleus. Including.
[0230]
In the present invention, it is particularly preferable to use a sensitizing dye having spectral sensitivity in the infrared. Examples of the infrared spectral sensitizing dye preferably used include, for example, infrared spectral sensitizing dyes disclosed in U.S. Pat. Nos. 4,536,473, 4,515,888, and 4,959,294. It is. As the infrared spectral sensitizing dye used in the present invention, a long-chain polymethine dye characterized by having a sulfinyl group substituted on the benzene ring of a benzazole ring is particularly preferable.
[0231]
The above-mentioned infrared sensitizing dyes are described in, for example, FM Hammer: The Chemistry of Heterocyclic Compounds, vol. 18, The Cyanine Dyes and Related Compounds (A. Weissberger ed., N.C., 19th. It can be easily synthesized by the method described above.
[0232]
The time for adding these infrared sensitizing dyes is preferably from the preparation of the silver halide to the mixing with the aliphatic carboxylic acid silver salt. Further, it is preferable to add a so-called solid dispersion state dispersed in fine particles to a photosensitive emulsion containing silver halide particles. Also, like the heteroatom-containing compound having an adsorptivity to the silver halide grains, the chemical sensitization can be performed after adding and adsorbing the silver halide grains prior to the chemical sensitization. Thereby, the dispersion of the chemical sensitization center nucleus can be prevented, and high sensitivity and low fog can be achieved.
[0233]
The above-mentioned spectral sensitizing dyes may be used alone, or a combination thereof may be used, and a combination of sensitizing dyes is often used particularly for supersensitization.
[0234]
(Super sensitization)
Emulsions containing photosensitive silver halide and silver aliphatic carboxylate used in silver salt photothermographic materials are dyes having no spectral sensitizing effect together with sensitizing dyes, or substantially do not absorb visible light. As the substance, a substance exhibiting a supersensitizing effect may be contained in the emulsion, whereby the silver halide grains may be supersensitized.
[0235]
Useful sensitizing dyes, combinations of dyes exhibiting supersensitization, and substances exhibiting supersensitization are described in RD17643, page 23, section IV-J (issued in December 1978), Japanese Patent Publication No. 9-25500, As described in, for example, JP-A-59-19032, JP-A-59-192242, and JP-A-5-341432, the superaromatic sensitizer is preferably a heteroaromatic mercapto compound or a mercapto derivative compound represented by the following.
[0236]
Ar-SM
In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferred heteroaromatic rings are benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, Purine, quinoline or quinazoline. However, it may contain other heteroaromatic rings.
[0237]
In addition, a mercapto derivative compound which substantially forms the above-mentioned mercapto compound when contained in a dispersion of a silver salt of an aliphatic carboxylic acid and / or a silver halide grain emulsion is also included. Particularly, mercapto derivative compounds shown below are preferred examples.
[0238]
Ar-SS-Ar
Ar in the formula has the same meaning as in the case of the mercapto compound represented above.
[0239]
The above-mentioned heteroaromatic ring includes, for example, a halogen atom (chlorine, bromine, iodine, etc.), a hydroxyl group, an amino group, a carboxyl group, an alkyl group (having one or more carbon atoms, preferably one to four carbon atoms). ) And an alkoxy group (having one or more carbon atoms, preferably 1 to 4 carbon atoms).
[0240]
In addition to the above supersensitizers, compounds represented by the general formula (1) and macrocyclic compounds described in paragraph “0012” of JP-A-2001-215652 can be used as supersensitizers.
[0241]
The macrocyclic compound is preferably a 9-membered or more macrocyclic compound containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom and a selenium atom as a hetero atom. Further, a 12-24 membered ring is preferable, and a 15-21 membered ring is more preferable. A typical compound is a compound known as a crown ether, which was synthesized by Pederson in 1967, and which has been synthesized in many cases since its unique quality was reported.
[0242]
These compounds are C.I. J. Pederson: J.M. Am. Chem. Soc. , 86 (2495), 7017-7036 (1967); W. Gokel, S.M. H, Korzeniowski: Macrocyclic polyether synthesis, Springer-Vergal, (1982), Oda, Shono, Tabushi, Ed .; Crown ether chemistry, Chemical Doujin (1978), Tabushi, Ed .: Host-guest, Kyoritsu Shuppan (1979), Sasaki, Koga : Synthetic Organic Chemistry, Vol. 45 (6), pages 571-582 (1987) and the like.
[0243]
The supersensitizer that can be used in the present invention is preferably used in the emulsion layer containing the organic silver salt and silver halide grains in the range of 0.001 to 1.0 mol per mol of silver. Particularly preferably, it is in the range of 0.01 to 0.5 mol.
[0244]
(binder)
Suitable binders for silver salt photothermographic materials are transparent or translucent and generally colorless and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic, polyvinyl alcohol (PVA), hydroxy Ethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone (PVP), casein, starch, polyacrylic acid, polymethylmethacrylic acid, polyvinyl chloride, polymethacrylic acid, copoly (styrene-maleic anhydride), copoly (styrene- (Acrylonitrile), copoly (styrene-butadiene), polyvinyl acetal (polyvinyl formal and polyvinyl butyral, etc.), polyesters, polyurethanes, phenoxy resin, polyvinylidene chloride, poly Pokishido, polycarbonates, polyvinyl acetate, cellulose esters, polyamides such. These may be hydrophilic or non-hydrophilic.
[0245]
The preferred binder for the image forming layer of the silver salt photothermographic material of the present invention is polyvinyl acetal, and the particularly preferred binder is polyvinyl butyral. Details will be described later. Further, for non-image forming layers such as an overcoat layer and an undercoat layer, particularly a protective layer and a back coat layer, a cellulose ester having a higher softening temperature, particularly triacetyl cellulose (TAC), cellulose acetate butyrate, And the like. In addition, if necessary, the above binders may be used in combination of two or more.
[0246]
Such a binder is used in a range effective to function as a binder. Effective ranges can be readily determined by those skilled in the art. For example, as an index when at least the aliphatic carboxylic acid silver salt is retained in the image forming layer, the ratio (mass ratio) of the binder to the aliphatic carboxylic acid silver salt is 15: 1 to 1: 2, particularly 8: 1. A range of 範 囲 1: 1 is preferred. That is, the binder amount of the image forming layer is 1.5 to 6 g / m²It is preferable that More preferably, 1.7 to 5 g / m²It is. 1.5g / m²If it is less than 10, the density of the unexposed portion is significantly increased, and may not be usable.
[0247]
In the present invention, it is preferable that the heat transition temperature after development at a temperature of 100 ° C. or higher is 46 to 200 ° C. The thermal transition point temperature in the present invention is a VICAT softening point or a value indicated by a ring and ball method, and is a differential scanning calorimeter (DSC), for example, EXSTAR 6000 (manufactured by Seiko Denshi), DSC220C (manufactured by Seiko Denshi Kogyo) , DSC-7 (manufactured by PerkinElmer) or the like, and indicates an endothermic peak when the thermally developed image-forming layer is isolated and measured. Generally, a polymer compound has a glass transition point (Tg). However, in a silver salt photothermographic material, a large endothermic peak appears at a place lower than the Tg value of a binder resin used in an image forming layer. Appears. Focusing attention on this heat transition temperature, as a result of intensive studies, it has been found that setting this heat transition temperature to 46 to 200 ° C. not only increases the robustness of the formed coating film, but also increases sensitivity, maximum density, and image quality. Photographic performance such as storage stability is greatly improved.
[0248]
Tg was determined by the method described in Brand Polymer, et al., “Polymer Handbook”, pages III-139 to III-179 (1966, Wiley and Sun, Inc.), and the binder was a copolymer resin. Tg in this case is obtained by the following equation.
[0249]
Tg (copolymer) (° C.) = V₁Tg₁+ V₂Tg₂+ ... + v_nTg_n
Where v₁, V₂... v_nRepresents the mass fraction of the monomers in the copolymer, and Tg₁, Tg₂... Tg_nRepresents Tg (° C.) of a homopolymer obtained from each monomer in the copolymer. The accuracy of the Tg calculated according to the above equation is ± 5 ° C.
[0250]
In a silver salt photothermographic material, a conventionally known polymer compound may be used as a binder contained in an image forming layer containing a silver aliphatic carboxylate, a photosensitive silver halide particle, a reducing agent, and the like on a support. Can be. It has a Tg of 70 to 105 ° C, a number average molecular weight of 1,000 to 1,000,000, preferably 10,000 to 500,000, and a degree of polymerization of about 50 to 1,000. Such examples include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylates, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic esters, styrene, butadiene, ethylene, vinyl butyral, vinyl acetal, There are compounds comprising a polymer or copolymer containing an ethylenically unsaturated monomer such as vinyl ether as a constitutional unit, a polyurethane resin, and various rubber resins.
[0251]
Further, phenol resins, epoxy resins, polyurethane-curable resins, urea resins, melamine resins, alkyd resins, formaldehyde resins, silicone resins, epoxy-polyamide resins, polyester resins and the like can be mentioned. These resins are described in detail in "Plastic Handbook" issued by Asakura Shoten.
[0252]
These polymer compounds are not particularly limited, and may be a homopolymer or a copolymer as long as the derived polymer has a Tg in the range of 70 to 105 ° C.
[0253]
Examples of the polymer or copolymer containing such an ethylenically unsaturated monomer as a constituent unit include alkyl (meth) acrylates, aryl (meth) acrylates, alkyl cyanoacrylates, and cyanoacrylic acid. Aryl esters and the like can be mentioned, and their alkyl groups and aryl groups may be substituted, and specifically, methyl, ethyl, propyl, i-propyl, butyl, i-butyl, sec-butyl, t- Butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl, dimethylaminophenoxyethyl, furfuryl, tetrahydrofurfuryl, Phenyl, cresyl, naph 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2-acetoacetoxyethyl, 2-ethoxyethyl, 2-i- Propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) ethyl, 2-diphenylphosphorylethyl, ω-methoxypolyethylene glycol ( Additional mole number n = 6), allyl, dimethylaminoethyl methyl chloride salt and the like.
[0254]
In addition, the following monomers can be used.
Vinyl esters: vinyl acetate, vinyl propionate, vinyl butyrate, vinyl i-butyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxy acetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate, and the like.
[0255]
N-substituted acrylamides, N-substituted methacrylamides and acrylamide, methacrylamide: N-substituents include methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethylaminoethyl Phenyl, dimethyl, diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl), diacetone and the like.
[0256]
Olefins: dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like.
[0257]
Styrenes: methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, i-propyl styrene, t-butyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, bromostyrene, methyl methyl vinyl benzoate etc.
[0258]
Vinyl ethers: methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether and the like.
[0259]
N-substituted maleimides: N-substituents include methyl, ethyl, propyl, butyl, t-butyl, cyclohexyl, benzyl, dodecyl, phenyl, 2-methylphenyl, 2,6-diethylphenyl, 2-chlorophenyl and the like. Etc.
[0260]
Others: butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate, diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, dibutyl fumarate, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, glycidyl acrylate, glycidyl methacrylate, N-vinyloxazolidone, N-vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalonnitrile, vinylidene chloride and the like.
[0261]
Of these, particularly preferred examples include alkyl methacrylates, aryl methacrylates, and styrenes. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. A polymer compound having an acetal group has excellent compatibility with the aliphatic carboxylic acid to be generated, and therefore has a large effect of preventing the film from being softened, and thus is preferable.
[0262]
(Crosslinking agent)
It is known that the use of a cross-linking agent with respect to the binder improves film formation and reduces development unevenness, but it also has an effect of suppressing fogging during storage and suppressing generation of printout silver after development. .
[0263]
Examples of the cross-linking agent used in the present invention include various cross-linking agents conventionally used for silver halide photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, ethyleneimine-based, and the like described in JP-A-50-96216. A vinyl sulfone-based, sulfonic ester-based, acryloyl-based, carbodiimide-based, or silane-based crosslinking agent can be used, but an isocyanate compound, a silane compound, an epoxy compound, or an acid anhydride is preferable.
[0264]
The crosslinking agent can be added to any layer on the image forming layer side of the support such as an image forming layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer, and may be added to one or more of these layers. Can be added.
[0265]
(Mat agent)
In the surface layer of the silver salt photothermographic material (even when a non-image forming layer is provided on the image forming layer side or on the opposite side of the image forming layer with the support interposed), handling before development and image formation after thermal development It is preferable to contain a matting agent in order to prevent scratching, and it is preferable to contain the matting agent in a mass ratio of 0.1 to 30% based on the binder.
[0266]
The material of the matting agent may be either an organic substance or an inorganic substance. Examples of the inorganic substance include silica described in Swiss Patent 330,158 and the like, glass powder described in French Patent 1,296,995 and the like, and alkaline earth metal or cadmium described in British Patent 1,173,181 and the like. And carbonates such as zinc and the like can be used as a matting agent. Examples of the organic substance include starch described in U.S. Pat. No. 2,322,037, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, etc., and polyvinyl described in Japanese Patent Publication No. 44-3643. Alcohols, such as polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in U.S. Pat. No. 3,079,257, and polycarbonate described in U.S. Pat. No. 3,022,169. Organic matting agents can be used.
[0267]
The matting agent preferably has a uniform particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm. The matting agent preferably has a variation coefficient of the particle size distribution of 50% or less, more preferably 40% or less, and particularly preferably 30% or less.
[0268]
Here, the variation coefficient (%) of the particle size distribution is a value represented by the following equation.
Coefficient of variation of particle size distribution = (standard deviation of particle size / average value of particle size) × 100
The method for adding the matting agent may be a method in which the matting agent is dispersed in the coating solution in advance, or a method in which the matting agent is sprayed before the drying is completed after the coating solution is applied. When a plurality of types of matting agents are added, both methods may be used in combination.
[0269]
(Support, auxiliary layer, etc.)
Examples of the material of the support used for the silver salt photothermographic material include various polymer materials, glass, wool cloth, cotton cloth, paper, and metal (aluminum, etc.). What can be processed into a flexible sheet or roll is suitable. Accordingly, as a support used in the silver salt photothermographic material of the present invention, a plastic film (such as a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film or a polycarbonate film) is used. Are preferred, and a biaxially stretched polyethylene terephthalate film is particularly preferred. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.
[0270]
The silver salt photothermographic material of the present invention has at least one image forming layer on a support. Although only the image forming layer may be formed on the support, it is preferable to form at least one non-image forming layer on the image forming layer. For example, a protective layer is provided on the image forming layer for the purpose of protecting the image forming layer, and between the silver salt photothermographic material and the silver salt photothermographic material-conveying roll on the opposite surface of the support. In order to prevent “sticking”, a back coat layer is preferably provided.
[0271]
As the binder used for the protective layer and the back coat layer, a polymer having a higher Tg than the image forming layer and hardly causing abrasion and deformation, for example, a polymer such as cellulose acetate or cellulose acetate butyrate is selected. In addition, two or more image forming layers may be provided on one side of the support, or one or more layers may be provided on both sides of the support, for gradation adjustment or the like.
[0272]
In the silver salt photothermographic material, in order to control the amount or wavelength distribution of light transmitted through the image forming layer, a filter layer is formed on the same side as the image forming layer or on the opposite side, or a dye or It is preferable to include a pigment.
[0273]
As the dye to be used, known compounds that absorb light in various wavelength ranges according to the color sensitivity of the silver salt photothermographic material can be used. For example, when a silver salt photothermographic material is used as an image recording material using infrared light, a squarylium dye having a thiopyrylium nucleus, a squarylium dye having a pyrylium nucleus, or a squarylium dye disclosed in JP-A-2001-83655. It is preferred to use a thiopyrylium croconium dye or a pyrylium croconium dye similar to the dye.
[0274]
The compound having a squarylium nucleus is a compound having 1-cyclobuten-2-hydroxy-4-one in a molecular structure, and the compound having a croconium nucleus is a compound having 1-cyclopenten-2-hydroxy-one in a molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present invention, these dyes are collectively referred to as squarylium dyes for convenience. As the dye, a compound described in JP-A-8-201959 is also preferable.
[0275]
(Coating of silver salt photothermographic materials)
The silver salt photothermographic material of the present invention can be formed by preparing a coating solution obtained by dissolving or dispersing the above-described constituent layer materials in a solvent, applying a plurality of coating solutions at the same time, and then performing a heat treatment. preferable. Here, the “multi-layer coating at the same time” means that a coating liquid for each constituent layer (image forming layer, protective layer, back layer, etc.) is prepared, and when applying the coating liquid to a support, coating and drying are repeated for each layer individually. Rather, it means that the respective constituent layers can be formed in a state where the steps of performing the multi-layer coating and drying at the same time can be performed at the same time. That is, the upper layer is provided before the remaining amount of all the solvents in the lower layer becomes 70% by mass or less.
[0276]
There is no particular limitation on the method of simultaneously applying multiple layers of each constituent layer, for example, using a known method such as a bar coater method, a curtain coat method, an immersion method, an air knife method, a hopper application method, or an extrusion application method. Can be. Among these, a pre-metering type coating method called an extrusion coating method is more preferable. The extrusion coating method is suitable for precision coating and organic solvent coating since there is no volatilization on the slide surface unlike the slide coating method. Although this coating method has been described on the side having the image forming layer, the same applies to the case where the back coat layer is provided and the coating is performed together with the undercoating.
[0277]
(Exposure method)
In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferred method, there is a method using a laser scanning exposure machine in which the angle between the exposure surface of the photosensitive material and the scanning laser beam does not become substantially perpendicular. Here, “not substantially vertical” means, as the angle closest to vertical during laser scanning, preferably 55 to 88 °, more preferably 60 to 86 °, and still more preferably 65 to 84 °. , Most preferably 70-82 °.
[0278]
The beam spot diameter on the exposed surface of the photographic material when the laser light is scanned on the silver salt photothermographic dry imaging material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable because the spot diameter is smaller in that the “shift angle” of the laser incident angle from the perpendicular can be reduced. Note that the lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration due to reflected light such as occurrence of unevenness like interference fringes.
[0279]
Also, as a second method, it is preferable to perform exposure using a laser scanning exposure device that emits a scanning laser beam that is a vertical multi. Compared with the scanning laser beam in the longitudinal single mode, image quality deterioration such as occurrence of interference fringe-like unevenness is reduced.
[0280]
To achieve vertical multiplication, a method of using return light due to multiplexing, superimposing high frequency, or the like is preferable. In addition, the vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.
[0281]
In the image recording methods of the first and second embodiments, the laser used for scanning exposure is a solid laser such as a ruby laser, a YAG laser, or a glass laser, which is generally well known; a He-Ne laser, Ar ion laser, Kr ion laser, CO₂Laser, CO laser, He-Cd laser, N₂Lasers, gas lasers such as excimer lasers; semiconductor lasers such as InGaP lasers, AlGaAs lasers, GaAsP lasers, InGaAs lasers, InAsP lasers, CdSnP lasers, and GaSb lasers; Of these, among these, it is preferable to use a semiconductor laser having a wavelength of 600 to 1200 nm from the viewpoint of maintenance and the size of the light source. In a laser used in a laser imager or a laser imagesetter, the beam spot diameter on the material exposure surface when scanning a photographic material is generally 5 to 75 μm as a short axis diameter and 5 as a long axis diameter. The scanning speed of the laser beam can be set to an optimum value for each silver halide photothermographic material by the sensitivity and laser power at the laser oscillation wavelength inherent to the photographic material.
[0282]
(Heat development method)
The development conditions for silver halide photothermographic materials vary depending on the equipment, equipment, or means used, but typically involve heating the imagewise exposed photographic material at a suitable elevated temperature. The latent image obtained after exposure is developed by heating the photographic material at a moderately high temperature (about 100-200 ° C.) for a sufficient time (typically about 1 second to about 2 minutes). If the heating temperature is lower than 100 ° C., a sufficient image density cannot be obtained in a short time, and if it exceeds 200 ° C., the binder is melted, and not only the image itself, such as transfer to a roller, but also transportability and a developing machine. Also have an adverse effect.
[0283]
By heating, a silver image is generated by a redox reaction between a silver aliphatic carboxylate (which functions as an oxidizing agent) and a reducing agent. This reaction process proceeds without any supply of a processing liquid such as water from the outside.
[0284]
The heating apparatus, apparatus and means may be performed by a typical heating means such as a hot plate, an iron, a hot roller, and a heat generator using carbon or white titanium. More preferably, the silver salt photothermographic material provided with the protective layer is subjected to heat treatment by bringing the surface having the protective layer into contact with a heating means, in order to perform uniform heating, and to improve thermal efficiency and workability. It is preferable that the surface is conveyed while being brought into contact with a heat roller, subjected to a heat treatment and developed.
[0285]
In the exposure of the silver salt photothermographic material, it is desirable to use a light source appropriate for the color sensitivity imparted to the photographic material. For example, when the photosensitive material can be sensed by infrared light, any light source can be applied as long as it is in the infrared light range, but the laser power can be high and the photosensitive material can be transparent. From these points, an infrared semiconductor laser (780 nm, 820 nm) is more preferably used.
[0286]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. Unless otherwise specified, “parts” in the examples represent “parts by mass” and “%” represents “% by mass”.
[0287]
Example 1
<Synthesis of composite copolymer aqueous dispersion ALX01>
190.0 ml of pure water was added to a 1000 ml four-necked flask (hereinafter referred to as a reaction vessel) equipped with a full zone blade stirrer, a thermometer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser. Copolyester 1 was slowly added over 10 minutes. Thereafter, the reactor was heated until the internal temperature reached 95 ° C., and the temperature was maintained at 95 ° C. for 3 hours. In the dropping funnel, 4.8 g of methyl methacrylate, 0.8 g of butyl acrylate, and 2.4 g of ethyl acrylate were weighed, mixed, and stirred. After heating at 95 ° C. for 3 hours, the internal temperature of the reactor was lowered to 80 ° C., and 343 g of an aqueous dispersion of tin oxide compound 1 was added on the way. Thereafter, nitrogen gas was blown into the reactor for 30 minutes. When the temperature in the kettle reached 80 ° C., 0.18 g of ammonium peroxodisulfate was added. Five minutes after the addition, the mixed monomer was dropped from the dropping funnel in 10 minutes. When the dropping funnel became empty, 6 ml of pure water was put into the funnel and the monomer in the tube was sent out.
[0288]
The reaction was carried out while maintaining the internal temperature at 80 ° C. for 3 hours after the addition of the polymerization initiator. Thereafter, the mixture was cooled with cold water until the internal temperature became 30 ° C. or lower, to obtain a composite copolymer aqueous dispersion ALX01 of the present invention.
[0289]
Except that the composition of the vinyl monomer, the type of the tin oxide compound, and the ratio of tin oxide / water-dispersible copolymerized polyester / vinyl monomer shown in Table 1 were changed, the aqueous composite copolymer dispersion ALX01 was changed. In the same manner as in the synthesis of the above, aqueous dispersions of composite copolymers ALX02 to ALX17 of the present invention and comparative aqueous dispersions were synthesized.
[0290]
[Table 1]

[0291]
Example 2
A silver salt photothermographic material sample was prepared as follows.
[0292]
<Preparation of undercoated support>
0.5 kV · A · min / m on one side of a PET film base (thickness: 175 μm) colored blue with a concentration of 0.170²After that, a subbing layer a was applied thereon by using the following subbing coating solution A on the image forming layer side so that the dry film thickness was 0.2 μm. Further, on the other side, similarly, 0.5 kV · A · min / m²After that, the undercoat layer b was applied thereon by using the following backing layer side undercoat coating solution B such that the dry film thickness became 0.1 μm. Thereafter, heat treatment was performed at 130 ° C. for 15 minutes in a heat treatment oven having a film transport device composed of a plurality of roll groups to produce a subbed support.
(Image forming layer side subbing coating solution A)
74 g of a copolymer latex liquid (solid content: 30%) of butyl acrylate / t-butyl acrylate / styrene / 2-hydroxyethyl acrylate (30/20/25/25% ratio), surfactant (UL-1) 0.1. 1 g and 0.5 g of methylcellulose were mixed. Further, 1.3 g of silica particles (Syloid 350: manufactured by Fuji Silysia Ltd.) was added to 100 g of water, and dispersion treatment was performed for 30 minutes with an ultrasonic dispersing machine (manufactured by ALEX Corporation: Ultrasonic Generator, frequency 25 kHz, 600 W). , And finally finished to 1000 ml with water to obtain a subbing coating solution A.
(Backing layer side coating liquid B)
56 g of the aqueous dispersion of composite copolymer ALX01 and 0.1 g of the surfactant (UL-1) were mixed, and the mixture was made up to 1000 ml with water to obtain a subbing coating liquid B.
[0293]
Embedded image

[0294]
(Backing layer coating solution)
While stirring 830 g of methyl ethyl ketone (MEK), 84.2 g of cellulose acetate butyrate (manufactured by Eastman Chemical: CAB381-20) and 4.5 g of a polyester resin (manufactured by Bostic: VitelPE2200B) were added and dissolved. 0.30 g of infrared dye 1 was added to the solution, and 4.5 g of a fluorine-based activator (Surflon KH40 manufactured by Asahi Glass Co., Ltd.) and 4 g of a fluorine-based activator (Dainippon Ink Co., Ltd.) dissolved in 43.2 g of methanol: 2.3g of Megafag F120K) was added and stirred thoroughly until dissolved. Finally, 75 g of silica (manufactured by WR Grace: Syloid 64X6000) dispersed in MEK at a concentration of 1% with a dissolver-type homogenizer was added thereto, followed by stirring to obtain a backing layer coating solution.
[0295]
Embedded image

[0296]
The coating solution for the backing layer was applied and dried on the undercoating side of the undercoated support 1 by an extrusion coater so that the dried film thickness became 3.5 μm. Drying was performed for 5 minutes using a drying air having a drying temperature of 100 ° C. and a dew point temperature of 10 ° C.
[0297]
<Preparation of photosensitive silver halide emulsion>
Solution (A1)
88.3 g of phenylcarbamoylated gelatin
10% aqueous solution of compound (K) in methanol 10 ml
Potassium bromide 0.32g
Finish to 5429ml with water
Solution (B1)
0.67mol / L silver nitrate aqueous solution 2635ml
Solution (C1)
Potassium bromide 51.55 g
1.47 g of potassium iodide
Finish to 660ml with water
Solution (D1)
Potassium bromide 154.9g
4.41 g of potassium iodide
Osmium chloride (1% solution) 0.93ml
Make up to 1982 ml with water.
Solution (E1)
0.4mol / L potassium bromide aqueous solution The following silver potential control amount
Solution (F1)
Potassium hydroxide 0.71g
Finish with water to 20ml
Solution (G1)
56% acetic acid aqueous solution 18.0 ml
Solution (H1)
1.72 g of anhydrous sodium carbonate
Make up to 151 ml with water.
[0298]
Compound (K): HO (CH₂CH₂O)_n[CH (CH₃) CH₂O]₁₇(CH₂CH₂O)_mH (m + n = 5-7)
Using a mixing stirrer disclosed in JP-B-58-58288 and JP-B-58-58289, 1/4 of the solution (B1) and the entire amount of the solution (C1) were added to the solution (A1) at a temperature of 40 ° C. and a pAg of 8.09. The mixture was added by a simultaneous mixing method over 4 minutes and 45 seconds to form nuclei. One minute later, the entire amount of the solution (F1) was added, followed by 20 ml of a 5% aqueous solution of 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene. During this time, pAg was appropriately adjusted using the aqueous solution (E1). After a lapse of 6 minutes, the 量 amount of the solution (B1) and the entire amount of the solution (D1) were added over 14 minutes and 15 seconds by a double jet method while controlling the temperature at 25 ° C. and the pAg at 8.09. After stirring for 5 minutes, the entire solution (G1) was added, and the silver halide emulsion was precipitated. The supernatant was removed except for 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The supernatant was removed except for the sedimented portion of 1500 ml, and 10 L of water was further added. After stirring, the silver halide emulsion was sedimented. After removing the supernatant liquid leaving 1500 ml of the sedimented portion, the solution (H1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so as to be 1161 g per 1 mol of silver to obtain a photosensitive silver halide emulsion.
[0299]
This emulsion was monodispersed cubic silver iodobromide grains having an average grain size of 0.034 μm, a grain size variation coefficient of 14%, and a [100] face ratio of 92%.
[0300]
Next, 240 ml of a triphenylphosphine sulfide (0.5% methanol solution) sensitizer was added to the above emulsion, and a chloroauric acid sensitizer equivalent to 1/20 mol of the sensitizer was added. The mixture was stirred for 120 minutes to perform chemical sensitization. This is used as a photosensitive silver halide emulsion.
[0301]
<Preparation of powdered aliphatic carboxylic acid silver salt>
130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid, and 2.3 g of palmitic acid were dissolved in 4720 ml of pure water at 80 ° C. Next, 540.2 ml of a 1.5 M / L aqueous sodium hydroxide solution was added, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., 45.3 g of the photosensitive silver halide emulsion and 450 ml of pure water were added and stirred for 5 minutes.
[0302]
Next, 702.6 ml of a 1 M / L silver nitrate solution was added over 2 minutes, and the mixture was stirred for 10 minutes to obtain a silver aliphatic carboxylate dispersion. Thereafter, the obtained silver salt of a fatty acid carboxylate is transferred to a washing vessel, deionized water is added thereto, and after stirring, the mixture is allowed to stand to float and separate the silver salt of a fatty acid carboxylate. Removed. After that, washing with deionized water and draining are repeated until the conductivity of the waste water reaches 50 μS / cm, and centrifugal dehydration is performed. The obtained cake-like aliphatic carboxylic acid silver salt is washed with a flash jet drier flash jet. Using a dryer (manufactured by Seishin Enterprise Co., Ltd.), the powder was dried until the water content became 0.1% under the operating conditions of a nitrogen gas atmosphere and hot air temperature at the dryer entrance, to obtain a powdered silver salt of aliphatic carboxylic acid. An infrared moisture meter was used to measure the water content of the aliphatic carboxylic acid silver salt.
[0303]
<Preparation of preliminary dispersion>
14.57 g of polyvinyl butyral resin is dissolved in 1457 g of MEK, and while stirring with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN, 500 g of powdered aliphatic carboxylic acid silver salt is gradually added and mixed well. Thus, a preliminary dispersion was prepared.
[0304]
<Preparation of photosensitive emulsion dispersion>
A media type disperser DISPERMAT SL- filled with zirconia beads having a diameter of 0.5 mm (manufactured by Torayceram Toray Co., Ltd.) with an internal volume of 80% so that the pre-dispersion liquid is retained in the mill for 1.5 minutes using a pump. The resulting emulsion was supplied to C12EX type (manufactured by VMA-GETZMANN) and dispersed at a mill peripheral speed of 8 m / sec to prepare a photosensitive emulsion dispersion.
[0305]
<Preparation of additive liquid A>
The following macrocyclic compound S-19 containing 1.0 g of a hetero atom and 0.31 g of potassium acetate were dissolved in 4.97 g of methanol to prepare an additive liquid A.
[0306]
<Preparation of infrared sensitizing dye liquid>
19.2 mg of the following infrared sensitizing dye 1-3 (exemplified compound of Japanese Patent Application No. 2001-308858), 1.488 g of 2-chlorobenzoic acid, 2.779 g of stabilizer 2, and 365 mg of 5-methyl-2-mercapto Benzimidazole was dissolved in 31.3 ml of MEK in a dark place to obtain an infrared sensitizing dye solution.
[0307]
<Preparation of additive liquid a>
As a developer, 14.0 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -octane (exemplified compound A-8) and 1.54 g of 4-methylphthalic acid, and 0.48 g of the red Outer dye 1 was dissolved in 110 g of MEK to prepare an additive solution a.
[0308]
<Preparation of additive liquid b>
3.43 g of phthalazine was dissolved in 40.9 g of MEK to prepare an additive liquid b.
[0309]
<Preparation of additive liquid c>
3.56 g of antifoggant 2 and 0.25 g of sodium p-toluenethiosulfonate were dissolved in 40.9 g of MEK to prepare an additive liquid c.
[0310]
<Preparation of coating solution for image forming layer>
Under an inert gas atmosphere (nitrogen 97%), 50 g of the photosensitive emulsion dispersion and 15.11 g of MEK were kept at 21 ° C. while stirring, 390 μl of antifoggant 1 (10% methanol solution) was added, and the mixture was stirred for 1 hour. did. Next, a methanol solution of iridium chloride was added in an amount of 1.0 × 10 5 per mole of silver halide.^-5Then, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 30 minutes. Subsequently, 0.21 g of the additive solution A and 1.32 g of the infrared sensitizing dye solution were added, followed by stirring for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl acetal resin as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4% MEK solution) was added and stirred for 15 minutes. While further stirring, 12.43 g of the additive solution a, 1.6 ml of a 10% MEK solution of aliphatic isocyanate (Desmodur N3300: manufactured by Mobay), 4.27 g of the additive solution b, and 10.0 g of the additive solution c were sequentially added. The mixture was added and stirred to obtain a coating solution for the image forming layer.
[0311]
<Preparation of matting agent dispersion>
7.5 g of cellulose acetate butyrate (manufactured by Eastman Chemical Co., Ltd .: CAB171-15) is dissolved in 42.5 g of MEK, and 5 g of calcium carbonate (Superiority Minerals: Super-Pflex200) is added thereto, followed by a dissolver-type homogenizer. The mixture was dispersed at 8000 rpm for 30 minutes to obtain a matting agent dispersion.
[0312]
<Preparation of coating solution for surface protective layer>
While stirring 865 g of MEK, 96 g of cellulose acetate butyrate (manufactured by Eastman Chemical: CAB171-15), 4.5 g of polymethyl methacrylic acid (manufactured by Rohm & Haas: Paraloid A-21), and vinyl sulfone compound (VSC) were added. 1.5 g, benzotriazole 1.0 g, and a fluorine-based activator (Asahi Glass Co., Ltd .; Surflon KH40) 1.0 g were added and dissolved. Next, 30 g of the above matting agent dispersion was added and stirred to obtain a coating solution for the surface protective layer.
[0313]
The structure of the additive used for each additive solution and coating solution is shown below.
[0314]
Embedded image

[0315]
<Preparation of silver salt photothermographic material sample>
A silver salt photothermographic material sample was prepared by simultaneously applying the above-mentioned image forming layer coating liquid and surface protective layer coating liquid on the undercoated support 1 using a known extrusion type coater. . The coating was performed using silver in the image forming layer at 1 × 10^-4g / m³This was performed so that the dry thickness of the surface protective layer was 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C., thereby obtaining a sample 101.
[0316]
In Sample 101, Samples 102 to 119 were produced in the same manner as in Sample 101, except that the kind of the additive for the backing layer side subbing layer was changed as shown in Table 2.
[0317]
<Exposure and development processing>
Each sample prepared as described above was exposed from the emulsion side by laser scanning using an exposing machine using a semiconductor laser having a wavelength of 800 to 820 nm and formed as a vertical multi-mode by a high frequency superimposition as an exposure source. At this time, an image was formed by setting the angle between the exposure surface of the sample and the exposure laser beam to 75 °. In addition, compared with the case where the angle was set to 90 °, an image having less unevenness and unexpectedly good sharpness and the like was obtained.
[0318]
Thereafter, heat development was performed at 110 ° C. for 15 seconds using an automatic developing machine having a heat drum so that the protective layer of the sample was in contact with the drum surface. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH.
[0319]
<Evaluation>
Samples 101 to 119 were evaluated for low humidity, heat treatment conductivity, and storage stability as follows.
[0320]
《Low humidity conductivity》
After the sample was conditioned for 24 hours under the conditions of 23 ° C. and 20% RH, the surface resistivity of the antistatic layer surface was measured at the applied voltage of 100 V using a Teraohmmeter VE-30 manufactured by Kawaguchi Electric Co. under the same conditions. The value was indicated by log (Ω / □).
[0321]
《Heat treatment conductivity》
The sample was heated in a thermostat at 140 ° C. for 180 seconds, and then conditioned for 24 hours at 23 ° C. and 20% RH, and then applied under the same conditions using a Kawaguchi Electric Co. Teraohmmeter VE-30. The value obtained by measuring the surface resistivity of the antistatic layer surface at a voltage of 100 V was indicated by log (Ω / □).
[0322]
《Storage stability》
An image obtained by exposure and heat development under the above conditions was measured with a densitometer.
[0323]
The storage stability was shown in Table 2 for each sample stored under the conditions of 40 ° C. and 80% RH for 10 days and the change in fog when stored under the conditions of 25 ° C. and 55% RH. In addition, as for the color tone, as a result of the visual evaluation, all of the samples 101 to 119 were almost the same as conventional medical films conventionally accepted in the market, and were at a very preferable level.
[0324]
[Table 2]

[0325]
As is clear from Table 2, the sample of the present invention has a low surface resistivity and does not deteriorate in conductivity even after heat treatment. Further, it can be seen that the reduction of fog with time can be realized without deteriorating the color tone.
[0326]
【The invention's effect】
According to the present invention, an antistatic aqueous dispersion that does not use an organic solvent or an organic amine and has a low burden on the environment; a plastic film having an antistatic layer with an excellent antistatic property that does not lose percolation transition even at a high temperature; Also provided a silver salt photothermographic dry imaging material with reduced fog.

Claims (13)

An aqueous composite copolymer dispersion obtained by dispersion-polymerizing a vinyl monomer in an aqueous dispersion in which a tin oxide compound and a water-dispersible copolymerized polyester are mixed. 2. The aqueous dispersion of a composite copolymer according to claim 1, wherein the composite copolymer contains an active methylene group. 2. The composite copolymer aqueous dispersion according to claim 1, wherein the composite copolymer contains a glycidyl group. The composite copolymer aqueous dispersion according to claim 1, wherein the composite copolymer contains an amide group. 2. The aqueous dispersion of a composite copolymer according to claim 1, wherein the composite copolymer contains a nitrile group. 2. The aqueous dispersion of a composite copolymer according to claim 1, wherein the composite copolymer contains a hydroxyl group. 2. The aqueous dispersion of a composite copolymer according to claim 1, wherein the composite copolymer contains a carboxyl group. The composite copolymer aqueous dispersion according to any one of claims 1 to 7, wherein the tin oxide-based compound is tin oxide. The composite copolymer aqueous dispersion according to any one of claims 1 to 7, wherein the tin oxide-based compound is antimony-doped tin oxide. The composite copolymer aqueous dispersion according to any one of claims 1 to 7, wherein the tin oxide-based compound is indium-doped tin oxide. The composite copolymer aqueous dispersion according to any one of claims 1 to 7, wherein the tin oxide-based compound is fluorine-doped tin oxide. A plastic film having an antistatic layer, wherein the aqueous composite copolymer dispersion according to any one of claims 1 to 11 is applied on a plastic film directly or via another layer. A silver salt photothermographic dry imaging material, characterized in that the composite copolymer aqueous dispersion according to any one of claims 1 to 11 is applied directly or via another layer on a plastic film.