JP4089272B2 - Silver salt photothermographic dry imaging material and image recording method thereof - Google Patents

Description

【００６８】
式中、Ｒ₁はアルキル基、置換アルキル基、アリール基又は置換アリール基を表すが好ましくはアリール基以外の基である。Ｒ₂は無置換アルキル基、置換アルキル基、無置換アリール基、置換アリール基、−ＣＯＲ₃又は−ＣＯＮＨＲ₃を表す。Ｒ₃はＲ₁と同義である。
【００６９】
Ｒ₁、Ｒ₂、Ｒ₃で表される無置換アルキル基としては、炭素数１〜２０のものが好ましく、特に好ましくは炭素数１〜６である。これらは直鎖であっても分岐していてもよく、好ましくは直鎖のアルキル基が好ましい。このような無置換アルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｔ−ブチル基、ｎ−アミル基、ｔ−アミル基、ｎ−ヘキシル基、シクロヘキシル基、ｎ−ヘプシル基、ｎ−オクチル基、ｔ−オクチル基、２−エチルヘキシル基、ｎ−ノニル基、ｎ−デシル基、ｎ−ドデシル基、ｎ−オクタデシル基等が挙げられるが、特に好ましくはメチル基もしくはプロピル基である。
【００７０】
無置換アリール基としては、炭素数６〜２０のものが好ましく、例えばフェニル基、ナフチル基等が挙げられる。上記のアルキル基、アリール基に置換可能な基としては、アルキル基（例えば、メチル基、ｎ−プロピル基、ｔ−アミル基、ｔ−オクチル基、ｎ−ノニル基、ドデシル基等）、アリール基（例えば、フェニル基等）、ニトロ基、水酸基、シアノ基、スルホ基、アルコキシ基（例えば、メトキシ基等）、アリールオキシ基（例えば、フェノキシ基等）、アシルオキシ基（例えば、アセトキシ基等）、アシルアミノ基（例えば、アセチルアミノ基等）、スルホンアミド基（例えば、メタンスルホンアミド基等）、スルファモイル基（例えば、メチルスルファモイル基等）、ハロゲン原子（例えば、フッ素原子、塩素原子、臭素原子）、カルボキシ基、カルバモイル基（例えば、メチルカルバモイル基等）、アルコキシカルボニル基（例えば、メトキシルボニル基等）、スルホニル基（例えば、メチルスルホニル基等）などが挙げられる。この置換基が２つ以上あるときは、同じでも異なっていてもよい。置換アルキル基の総炭素数は、１〜２０が好ましく、置換アリール基の総炭素数は６〜２０が好ましい。
【００７１】
Ｒ₂としては、−ＣＯＲ₃（Ｒ₃はアルキル基又はアリール基）、−ＣＯＮＨＲ₃（Ｒ₃はアリール基）が好ましい。ａ、ｂ、ｃは各繰り返し単位の質量をモル（ｍｏｌ）％で示した値であり、ａは４０〜８６モル％、ｂは０〜３０モル％、ｃは０〜６０モル％の範囲で、ａ＋ｂ＋ｃ＝１００モル％となる数を表し、特に好ましくは、ａが５０〜８６モル％、ｂが５〜２５モル％、ｃが０〜４０モル％の範囲である。ａ、ｂ、ｃの各組成比をもつ各繰り返し単位は、それぞれ同一のもののみで構成されていても、異なるもので構成されていてもよい。
【００７２】
本発明で用いることのできるポリウレタン樹脂としては、構造がポリエステルポリウレタン、ポリエーテルポリウレタン、ポリエーテルポリエステルポリウレタン、ポリカーボネートポリウレタン、ポリエステルポリカーボネートポリウレタン、ポリカプロラクトンポリウレタンなど公知のものが使用できる。ここに示した全てのポリウレタンについて、必要に応じ、−ＣＯＯＭ、−ＳＯ₃Ｍ、−ＯＳＯ₃Ｍ、−Ｐ＝Ｏ（ＯＭ）₂、−Ｏ−Ｐ＝Ｏ（ＯＭ）₂、（Ｍは水素原子、又はアルカリ金属塩基を表す）、−ＮＲ₂、−Ｎ⁺Ｒ₂（Ｒ₂は炭化水素基を表す）、エポキシ基、−ＳＨ、−ＣＮなどから選ばれる少なくとも一つ以上の極性基を共重合又は付加反応で導入したものを用いることが好ましい。このような極性基の量は１０^-1〜１０^-8モル／ｇであり、好ましくは１０^-2〜１０^-6モル／ｇである。これら極性基以外に、ポリウレタン分子末端に少なくとも１個ずつ、合計２個以上のＯＨ基を有することが好ましい。ＯＨ基は硬化剤であるポリイソシアネートと架橋して３次元の網状構造を形成するので、分子中に多数含むほど好ましい。特に、ＯＨ基が分子末端にある方が、硬化剤との反応性が高いので好ましい。ポリウレタンは、分子末端にＯＨ基を３個以上有することが好ましく、４個以上有することが特に好ましい。ポリウレタンを用いる場合は、ガラス転移温度が７０〜１０５℃、破断伸びが１００〜２０００％、破断応力は０．５〜１００Ｎ／ｍｍ²が好ましい。
【００７３】
本発明の上記一般式（Ｖ）で表される高分子化合物は、「酢酸ビニル樹脂」桜田一郎編（高分子化学刊行会、１９６２年）等に記載の一般的な合成方法で合成することができる。以下に、代表的な合成方法の例を挙げるが、本発明はこれらの代表的な合成例に限定されるものではない。
【００７４】
合成例１：Ｐ−１の合成
日本合成（株）製のポリビニルアルコール（ゴーセノールＧＨ１８）２０ｇと純水１８０ｇを仕込み、ポリビニルアルコールが１０質量％溶液になるように純水に分散した後、これを９５℃に昇温してポリビニルアルコールを溶解した後、７５℃まで冷却して、ポリビニルアルコール水溶液を用意し、更にこのポリビニルアルコール水溶液に、酸触媒として１０質量％の塩酸を１．６ｇ添加し、これを滴下液Ａとした。ついで、ブチルアルデヒド、アセトアルデヒドのｍｏｌ比１：１の混合物１１．５ｇを計量し、これを滴下液Ｂとした。冷却管と攪拌装置を取り付けた１０００ｍｌの４ツ口フラスコに１００ｍｌの純水を入れ、８５℃に加温し強攪拌した。これに滴下液Ａと滴下液Ｂを７５℃に保温した滴下ロートを用いて、攪拌下で２時間を要して同時滴下した。この際、攪拌速度に注意をして、析出する粒子の融着を防止しながら反応を行った。滴下終了後、酸触媒として１０質量％の塩酸を７ｇ追加し、温度８５℃で２時間攪拌を行い、十分に反応を行った。その後、４０℃まで冷却し、重曹を用いて中和し、水洗を５回繰り返した後、濾別してポリマーを取り出し乾燥し、Ｐ−１を得た。得られたＰ−１を、ＤＳＣを用いてＴｇを測定したところ、Ｔｇは７５℃であった。
【００７５】
その他、表１に記載のその他の高分子化合物も同様に合成した。これらの高分子化合物（ポリマー）は単独で用いてもよいし、２種類以上をブレンドして用いてもよい。
【００７６】
感光層には上記ポリマーを主バインダーとして用いることが好ましい。ここで言う主バインダーとは、感光層の全バインダーの５０質量％以上を上記ポリマーが占めている状態をいう。従って、全バインダーの５０質量％未満の範囲で他のポリマーをブレンドして用いてもよい。これらのポリマーとしては、ポリマーが可溶となる溶媒であれば、特に制限はない。より好ましくはポリ酢酸ビニル、ポリアクリル樹脂、ウレタン樹脂などが挙げられる。
【００７７】
以下に、本発明に係る高分子化合物の構成を示す。尚、表中のＴｇは、セイコー電子工業（株）製示差走査熱量計（ＤＳＣ）により測定した値である。
【００７８】
【表１】

【００７９】
尚、表１におけるＰ−９はＢ−７９（ソルーシア社製）である。
（架橋剤）
架橋剤を上記バインダーに対し用いることにより膜付きがよくなり、現像ムラが少なくなることは知られているが、本発明では、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。
【００８０】
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号に記載されているアルデヒド系、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、シラン化合物系架橋剤を用いうるが、好ましいのは以下に示すイソシアネート系化合物、シラン化合物、エポキシ化合物又は酸無水物である。
【００８１】
好適なものの一つである下記一般式〔１〕で表せるイソシアネート系及びチオイソシアネート系架橋剤について説明する。
【００８２】
一般式〔１〕
Ｘ＝Ｃ＝Ｎ−Ｌ−（Ｎ＝Ｃ＝Ｘ）_v
式中、ｖは１又は２であり、Ｌはアルキレン、アルケニレン、アリーレン基又はアルキルアリーレン基でありうる２価の連結基であり、Ｘは酸素又は硫黄原子である。
【００８３】
尚、上記一般式〔１〕で表せる化合物において、アリーレン基のアリール環は置換基を有し得る。好ましい置換基の例は、ハロゲン原子（例えば、臭素原子又は塩素原子）、ヒドロキシル基、アミノ基、カルボキシル基、アルキル基及びアルコキシ基から選択される。
【００８４】
上記イソシアネート系架橋剤は、イソシアネート基を少なくとも２個有しているイソシアネート類及びその付加体（アダクト体）であり、更に、具体的には、脂肪族ジイソシアネート類、環状基を有する脂肪族ジイソシアネート類、ベンゼンジイソシアネート類、ナフタレンジイソシアネート類、ビフェニルイソシアネート類、ジフェニルメタンジイソシアネート類、トリフェニルメタンジイソシアネート類、トリイソシアネート類、テトライソシアネート類、これらのイソシアネート類の付加体及びこれらのイソシアネート類と２価又は３価のポリアルコール類との付加体が挙げられる。
【００８５】
具体例としては、特開昭５６−５５３５号の１０頁から１２頁に記載されているイソシアネート化合物を利用することができる。
【００８６】
尚、イソシアネートとポリアルコールのアダクト体は、特に層間接着を良くし、層の剥離や画像のズレ及び気泡の発生を防止する能力が高い。かかるイソシアネートは光熱写真材料のどの部分に置かれてもよい。例えば支持体中（特に支持体が紙の場合、そのサイズ組成中に含ませることができる）感光層、表面保護層、中間層、アンチハレーション層、下引き層等の支持体の感光層側の任意の層に添加でき、これらの層の中の１層又は２層以上に添加することができる。
【００８７】
又、本発明において使用することが可能なチオイソシアネート系架橋剤としては、上記のイソシアネート類に対応するチオイソシアネート構造を有する化合物も有用である。
【００８８】
本発明において使用される上記架橋剤の添加量は、銀１モルに対して０．００１〜２モル、好ましくは０．００５〜０．５モルの範囲である。
【００８９】
上記イソシアネート化合物及びチオイソシアネート化合物は、上記の架橋剤として機能する化合物であることが好ましいが、上記の一般式においてｖが零（０）、即ち当該官能基を一つのみ有する化合物であっても良い結果が得られる。
【００９０】
本発明において架橋剤として使用できるシラン化合物の例としては、特願２０００−０７７９０４に開示されている一般式（１）又は一般式（２）で表せる化合物が挙げられる。
【００９１】
これらの一般式において、Ｒ¹〜Ｒ⁸はそれぞれ置換されてもよい直鎖、分枝又は環状の炭素数１〜３０のアルキル基（メチル基、エチル基、ブチル基、オクチル基、ドデシル基、シクロアルキル基等）、アルケニル基（プロペニル基、ブテニル基、ノネニル基等）、アルキニル基（アセチレン基、ビスアセチレン基、フェニルアセチレン基等）、アリール基又はヘテロ環基（フェニル基、ナフチル基、テトラヒドロピラン基、ピリジル基、フリル基、チオフェニル基、イミダゾール基、チアゾール基、チアジアゾール基、オキサジアゾール基等）を表し、置換基としては電子吸引性の置換基又は電子供与性の置換基何れをも有することができる。
【００９２】
Ｒ¹〜Ｒ⁸から選ばれる置換基の少なくとも１つが耐拡散性基又は吸着性基であることが好ましく、特にＲ²が耐拡散性基又は吸着性基であることが好ましい。
【００９３】
尚、耐拡散性基は、バラスト基とも呼ばれ炭素数が６以上の脂肪族基や炭素数が３以上のアルキル基が導入されているアリール基等が好ましい。耐拡散性は、バインダーや架橋剤の使用量によって異なるが、耐拡散性の基を導入することにより、室温状態の分子内の移動距離が抑制され経時での反応を抑制できる。
【００９４】
架橋剤として用いることができるエポキシ化合物としては、エポキシ基を１個以上有するものであればよく、エポキシ基の数、分子量、その他に制限はない。エポキシ基はエーテル結合やイミノ結合を介してグリシジル基として分子内に含有されることが好ましい。又エポキシ化合物は、モノマー、オリゴマー、ポリマー等の何れであってもよく、分子内に存在するエポキシ基の数は通常１〜１０個程度、好ましくは２〜４個である。エポキシ化合物がポリマーである場合は、ホモポリマー、コポリマーの何れであってもよく、その数平均分子量Ｍｎの特に好ましい範囲は２０００〜２００００程度である。
【００９５】
エポキシ化合物としては下記一般式〔２〕で表される化合物が好ましい。
【００９６】
【化４】

【００９７】
一般式〔２〕において、Ｒで表されるアルキレン基の置換基は、ハロゲン原子、水酸基、ヒドロキシアルキル基又はアミノ基から選ばれる基であることが好ましい。又Ｒで表される連結基中にアミド連結部分、エーテル連結部分、チオエーテル連結部分を有していることが好ましい。Ｘで表される２価の連結基としては−ＳＯ₂−、−ＳＯ₂ＮＨ−、−Ｓ−、−Ｏ−、又は−ＮＲ′−が好ましい。ここでＲ′は１価の基であり、電子吸引基であることが好ましい。
【００９８】
これらのエポキシ化合物は、１種のみを用いても２種以上を併用してもよい。その添加量は特に制限はないが、１×１０^-6〜１×１０^-2モル／ｍ²の範囲が好ましく、より好ましくは１×１０^-5〜１×１０^-3モル／ｍ²の範囲である。
【００９９】
エポキシ化合物は、感光層、表面保護層、中間層、アンチハレーション層、下引き層等の支持体の感光層側の任意の層に添加でき、これらの層の中の１層又は２層以上に添加することができる。又、併せて支持体の感光層と反対側の任意の層に添加することができる。尚、両面に感光層が存在するタイプの感材では何れの層であってもよい。
【０１００】
酸無水物は下記の構造式で示される酸無水物基を少なくとも１個有する化合物である。
【０１０１】
−ＣＯ−Ｏ−ＣＯ−
酸無水物はこのような酸無水基を１個以上有するものであればよく、酸無水基の数、分子量、その他に制限はないが、一般式〔Ａ〕で表される化合物が好ましい。
【０１０２】
【化５】

【０１０３】
一般式〔Ａ〕において、Ｚは単環又は多環系を形成するのに必要な原子群を表す。これらの環系は未置換であってもよく、置換されていてもよい。置換基の例には、アルキル基（例えば、メチル、エチル、ヘキシル）、アルコキシ基（例えば、メトキシ、エトキシ、オクチルオキシ）、アリール基（例えば、フェニル、ナフチル、トリル）、ヒドロキシル基、アリールオキシ基（例えば、フェノキシ）、アルキルチオ基（例えば、メチルチオ、ブチルチオ）、アリールチオ基（例えば、フェニルチオ）、アシル基（例えば、アセチル、プロピオニル、ブチリル）、スルホニル基（例えば、メチルスルホニル、フェニルスルホニル）、アシルアミノ基、スルホニルアミノ基、アシルオキシ基（例えば、アセトキシ、ベンゾキシ）、カルボキシル基、シアノ基、スルホ基、及びアミノ基が含まれる。置換基としては、ハロゲン原子を含まないものが好ましい。
【０１０４】
これらの酸無水物は、１種のみを用いても２種以上を併用してもよい。その添加量は特に制限はないが、１×１０^-6〜１×１０^-2モル／ｍ²の範囲が好ましく、より好ましくは１×１０^-5〜１×１０^-3モル／ｍ²の範囲である。
【０１０５】
本発明において酸無水物は、感光層、表面保護層、中間層、アンチハレーション層、下引き層等の支持体の感光層側の任意の層に添加でき、これらの層の中の１層又は２層以上に添加することができる。又、前記エポキシ化合物と同じ層に添加すしてもよい。
（還元剤）
本発明に用いられる還元剤としては、上述した一般式（Ｓ）で表されるビスフェノール誘導体が好ましく、より好ましくは上述した一般式（Ｔ）で表される環状構造を有する化合物である。該環は６員環であることが好ましい。
【０１０６】
一般式（Ｓ）において、Ｚは炭素原子とともに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、該環は、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。
【０１０７】
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。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も縮環してよい。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（例えば、フッ素原子、塩素原子、臭素原子等）、アルキル基（例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基等）、シクロアルキル基（例えば、シクロヘキシル基、シクロヘプチル基等）、アルケニル基（例えば、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基等）、シクロアルケニル基（例えば、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（例えば、エチニル基、１−プロピニル基等）、アルコキシ基（例えば、メトキシ基、エトキシ基、プロポキシ基等）、アルキルカルボニルオキシ基（例えば、アセチルオキシ基等）、アルキルチオ基（例えば、メチルチオ基、トリフルオロメチルチオ基等）、カルボキシル基、アルキルカルボニルアミノ基（例えば、アセチルアミノ基等）、ウレイド基（例えば、メチルアミノカルボニルアミノ基等）、アルキルスルホニルアミノ基（例えば、メタンスルホニルアミノ基等）、アルキルスルホニル基（例えば、メタンスルホニル基、トリフルオロメタンスルホニル基等）、カルバモイル基（例えば、カルバモイル基、Ｎ，Ｎ−ジメチルカルバモイル基、Ｎ−モルホリノカルボニル基等）、スルファモイル基（スルファモイル基、Ｎ，Ｎ−ジメチルスルファモイル基、モルフォリノスルファモイル基等）、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（例えば、メタンスルホンアミド基、ブタンスルホンアミド基等）、アルキルアミノ基（例えばアミノ基、Ｎ，Ｎ−ジメチルアミノ基、Ｎ，Ｎ−ジエチルアミノ基等）、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（例えば、メタンスルホニルアミノカルボニル基、エタンスルホニルアミノカルボニル基等）、アルキルカルボニルアミノスルホニル基（例えば、アセトアミドスルホニル基、メトキシアセトアミドスルホニル基等）、アルキニルアミノカルボニル基（例えば、アセトアミドカルボニル基、メトキシアセトアミドカルボニル基等）、アルキルスルフィニルアミノカルボニル基（例えば、メタンスルフィニルアミノカルボニル基、エタンスルフィニルアミノカルボニル基等）等が挙げられる。又、置換基が二つ以上ある場合は、同じでも異なっていても良い。特に好ましい置換基はアルキル基である。Ｒ₀′、Ｒ₀″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のアルキル基であることが好ましい。具体例としてはメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔ−ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基、シクロヘキシル基、シクロヘプチル基、１−メチルシクロヘキシル基、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基、１−シクロアルケニル基、２−シクロアルケニル基、エチニル基、１−プロピニル基等が挙げられる。より好ましくは、メチル基、エチル基、イソプロピル基、ｔ−ブチル基、シクロヘキシル基、１−メチルシクロヘキシル基等が挙げられる。好ましくはメチル基、ｔ−ブチル基、１−メチルシクロヘキシル基であり、最も好ましくはメチル基である。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ン基、キノリン基、イソキノリン基、イミダゾール基、ピラゾール基、トリアゾール基、オキサゾール基、チアゾール基、オキサジアゾール基、チアジアゾール基、テトラゾール基等の芳香族ヘテロ環基やピペリジノ基、モルホリノ基、テトラヒドロフリル基、テトラヒドロチエニル基、テトラヒドロピラニル基等の非芳香族ヘテロ環基が挙げられる。これらの基は更に置換基を有していても良く、該置換基としては前述の環上の置換基を挙げることができる。複数のＲ₀′、Ｒ₀″は同じでも異なっていても良いが、最も好ましくはすべてがメチル基の場合である。
【０１０８】
Ｒ_x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のアルキル基であることが好ましい。具体例としてはメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔ−ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基、シクロヘキシル基、シクロヘプチル基、１−メチルシクロヘキシル基、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基、１−シクロアルケニル基、２−シクロアルケニル基、エチニル基、１−プロピニル基等が挙げられる。より好ましくは、メチル基、エチル基、イソプロピル基、水素原子である。
【０１０９】
Ｑ₀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（メチル基、エチル基、プロピル基、イソプロピル基、ｔｅｒｔ−ブチル基、ペンチル基、ヘキシル基、シクロヘキシル基等）、ハロゲン化アルキル基（トリフルオロメチル基、パーフルオロオクチル基等）、シクロアルキル基（シクロヘキシル基、シクロペンチル基等）、アルキニル基（プロパルギル基等）、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（フェニル基等）、複素環基（ピリジル基、チアゾリル基、オキサゾリル基、イミダゾリル基、フリル基、ピロリル基、ピラジニル基、ピリミジニル基、ピリダジニル基、セレナゾリル基、スリホラニル基、ピペリジニル基、ピラゾリル基、テトラゾリル基等）、ハロゲン原子（塩素原子、臭素原子、ヨウ素原子、フッ素原子等）、アルコキシ基（メトキシ基、エトキシ基、プロピルオキシ基、ペンチルオキシ基、シクロペンチルオキシ基、ヘキシルオキシ基、シクロヘキシルオキシ基等）、アリールオキシ基（フェノキシ基等）、アルコキシカルボニル基（メチルオキシカルボニル基、エチルオキシカルボニル基、ブチルオキシカルボニル基等）、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基等）、スルホンアミド基（メタンスルホンアミド基、エタンスルホンアミド基、ブタンスルホンアミド基、ヘキサンスルホンアミド基、シクロヘキサンスルホンアミド基、ベンゼンスルホンアミド基等）、スルファモイル基（アミノスルホニル基、メチルアミノスルホニル基、ジメチルアミノスルホニル基、ブチルアミノスルホニル基、ヘキシルアミノスルホニル基、シクロヘキシルアミノスルホニル基、フェニルアミノスルホニル基、２−ピリジルアミノスルホニル基等）、ウレタン基（メチルウレイド基、エチルウレイド基、ペンチルウレイド基、シクロヘキシルウレイド基、フェニルウレイド基、２−ピリジルウレイド基等）、アシル基（アセチル基、プロピオニル基、ブタノイル基、ヘキサノイル基、シクロヘキサノイル基、ベンゾイル基、ピリジノイル基等）、カルバモイル基（アミノカルボニル基、メチルアミノカルボニル基、ジメチルアミノカルボニル基、プロピルアミノカルボニル基、ペンチルアミノカルボニル基、シクロヘキシルアミノカルボニル基、フェニルアミノカルボニル基、２−ピリジルアミノカルボニル基等）、アミド基（アセトアミド基、プロピオンアミド基、ブタンアミド基、ヘキサンアミド基、ベンズアミド基等）、スルホニル基（メチルスルホニル基、エチルスルホニル基、ブチルスルホニル基、シクロヘキシルスルホニル基、フェニルスルホニル基、２−ピリジルスルホニル基等）、アミノ基（アミノ基、エチルアミノ基、ジメチルアミノ基、ブチルアミノ基、シクロペンチルアミノ基、アニリノ基、２−ピリジルアミノ基等）、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いてもよい。ｎ及びｍは０〜２の整数を表すが、最も好ましくはｎ、ｍともに０の場合である。
【０１１０】
一般式（Ｔ）中、Ｑ₁はハロゲン原子、アルキル基、アリール基、又はヘテロ環基を表し、Ｑ₂は水素原子、ハロゲン原子、アルキル基、アリール基、又はヘテロ環基を表す。ハロゲン原子として具体的には塩素、臭素、フッ素、ヨウ素が挙げられる。好ましくはフッ素、塩素、臭素である。アルキル基として具体的には炭素数１〜１０のアルキル基であることが好ましい。具体例としてはメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔ−ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基、シクロヘキシル基、シクロヘプチル基、１−メチルシクロヘキシル基、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基、１−シクロアルケニル基、２−シクロアルケニル基、エチニル基、１−プロピニル基等が挙げられる。より好ましくは、メチル基、及びエチル基である。アリール基として具体的にはフェノル基、ナフチル基が挙げられる。ヘテロ環基としてはピリジル基、フリル基、チエニル基、オキサゾリル基等の５〜６員環のヘテロ芳香族基が好ましく挙げられる。Ｇは窒素原子又は炭素原子を表すが、好ましくは炭素原子である。ｎｇは０又は１を表すが好ましくは１である。Ｑ₁として最も好ましくはメチル基であり。Ｑ₂として好ましくは水素原子、又はメチル基であり最も好ましくは水素原子である。
【０１１１】
Ｚ₂は炭素原子及びＧとともに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、３〜１０員の非芳香族環としては前述の一般式（Ｓ）におけるものと同義である。
【０１１２】
Ｒ₀′、Ｒ₀″、Ｒ_x、Ｑ₀、ｎ、及びｍは一般式（Ｓ）におけるものと同義である。
【０１１３】
又、本発明に用いられる還元剤としては、その少なくとも一種が下記一般式（Ｂ）で表される化合物を採用することが好ましい。
【０１１４】
【化６】

【０１１５】
式中、Ｘはカルコゲン原子又はＣＨＲを表し、Ｒは水素原子、ハロゲン原子、炭素数が７以下の鎖状脂肪族基を表す。Ｒ′、Ｒ″はアルキル基を表す。
【０１１６】
一般式（Ｂ）中、Ｘが表すカルコゲン原子としては、具体的には硫黄原子、セレン原子、テルル原子であり、好ましくは硫黄原子である。Ｒは水素原子、ハロゲン原子、炭素数が７以下の鎖状脂肪族基を表すが、ハロゲン原子としては、例えば、フッ素原子、塩素原子、臭素原子等であり、炭素数が７以下の鎖状脂肪族基としては、例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ヘキシル基、ヘプチル基、ビニル基、アリル基、ブテニル基、ヘキサジエニル基、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基等が挙げられる。Ｒとしては炭素数が７以下の鎖状脂肪族基であることが好ましく、中でもメチル基、エチル基、イソプロピル基であることが好ましい。
【０１１７】
これらの基は更に置換基を有していても良く、置換基としては、ハロゲン原子（例えば、フッ素原子、塩素原子、臭素原子等）、シクロアルキル基（例えば、シクロヘキシル基、シクロヘプチル基等）、シクロアルケニル基（例えば、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（例えば、メトキシ基、エトキシ基、プロポキシ基等）、アルキルカルボニルオキシ基（例えば、アセチルオキシ基等）、アルキルチオ基（例えば、メチルチオ基、トリフルオロメチルチオ基等）、カルボキシル基、アルキルカルボニルアミノ基（例えば、アセチルアミノ基等）、ウレイド基（例えば、メチルアミノカルボニルアミノ基等）、アルキルスルホニルアミノ基（例えば、メタンスルホニルアミノ基等）、アルキルスルホニル基（例えば、メタンスルホニル基、トリフルオロメタンスルホニル基等）、カルバモイル基（例えば、カルバモイル基、Ｎ，Ｎ−ジメチルカルバモイル基、Ｎ−モルホリノカルボニル基等）、スルファモイル基（スルファモイル基、Ｎ，Ｎ−ジメチルスルファモイル基、モルフォリノスルファモイル基等）、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（例えば、メタンスルホンアミド基、ブタンスルホンアミド基等）、アルキルアミノ基（例えばアミノ基、Ｎ，Ｎ−ジメチルアミノ基、Ｎ，Ｎ−ジエチルアミノ基等）、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（例えば、メタンスルホニルアミノカルボニル基、エタンスルホニルアミノカルボニル基等）、アルキルカルボニルアミノスルホニル基（例えば、アセトアミドスルホニル基、メトキシアセトアミドスルホニル基等）、アルキニルアミノカルボニル基（例えば、アセトアミドカルボニル基、メトキシアセトアミドカルボニル基等）、アルキルスルフィニルアミノカルボニル基（例えば、メタンスルフィニルアミノカルボニル基、エタンスルフィニルアミノカルボニル基等）等が挙げられる。又、置換基が二つ以上ある場合は、同じでも異なっていても良い。
【０１１８】
Ｒ′、Ｒ″はアルキル基を表すが、具体的には炭素数１〜１０のアルキル基であることが好ましい。具体例としてはメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔ−ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基、シクロヘキシル基、シクロヘプチル基、１−メチルシクロヘキシル基、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基、１−シクロアルケニル基、２−シクロアルケニル基、エチニル基、１−プロピニル基等が挙げられる。より好ましくはメチル基、エチル基、イソプロピル基、ｔ−ブチル基、シクロヘキシル基、１−メチルシクロヘキシル基である。更に好ましくはメチル基、ｔ−ブチル基、１−メチルシクロヘキシル基であり、最も好ましくはメチル基である。これらの基は更に置換基を有していても良く、該置換基としては前述の環上の置換基を挙げることができる。複数のＲ′、Ｒ″は同じでも異なっていても良いが、最も好ましくはすべてがメチル基の場合である。
【０１１９】
以下に一般式（Ｓ）、（Ｔ）、及び（Ｂ）で表される化合物の具体例を列記するが本発明はこれらに限定されるものではない。
【０１２０】
【化７】

【０１２１】
【化８】

【０１２２】
【化９】

【０１２３】
【化１０】

【０１２４】
【化１１】

【０１２５】
【化１２】

【０１２６】
【化１３】

【０１２７】
【化１４】

【０１２８】
【化１５】

【０１２９】
【化１６】

【０１３０】
一般式（Ｓ）、（Ｔ）、及び（Ｂ）で表される化合物は従来公知の方法により容易に合成することができる。好ましい合成スキームを一般式（Ｓ）を例にとり以下に図示する。
【０１３１】
【化１７】

【０１３２】
即ち、好ましくは２当量のフェノール及び１当量のアルデヒドを無溶媒で、もしくは適当な有機溶媒で溶解又は懸濁させ、触媒量の酸を加えて、好ましくは−２０℃〜１２０℃の温度下で０．５〜６０時間反応させることにより好収率で目的とする一般式（Ｓ）で表される化合物を得ることができる。一般式（Ｔ）又は（Ｂ）で表される化合物についても同様である。
【０１３３】
有機溶媒として好ましくは、炭化水素系有機溶媒であり、具体的にはベンゼン、トルエン、キシレン、ジクロロメタン、クロロホルム等が挙げられる。好ましくはトルエンである。更に収率の点からは無溶媒で反応させることが最も好ましい。酸触媒としてあらゆる無機酸、有機酸を使用することができるが、濃塩酸、ｐ−トルエンスルホン酸、及び燐酸が好ましく用いられる。触媒量としては対応するアルデヒドに対して０．００１当量〜１．５当量使用することが好ましい。反応温度として好ましくは室温付近（１５〜２５℃）が好ましく、反応時間としては３〜２０時間が好ましい。
【０１３４】
本発明では米国特許第３，５８９，９０３号、同第４，０２１，２４９号若しくは英国特許第１，４８６，１４８号各及び特開昭５１−５１９３３号、同５０−３６１１０号、同５０−１１６０２３号、同５２−８４７２７号若しくは特公昭５１−３５７２７号公報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第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第３，８０１，３２１号に記載されてい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銀イオン還元剤として用いることができる。
【０１３５】
前記一般式（Ｓ）、（Ｔ）、及び（Ｂ）で表される化合物を始めとする還元剤の使用量は好ましくは銀１モル当り１×１０^-2〜１０モル、特に１×１０^-2〜１．５モルである。
【０１３６】
本発明の光熱写真ドライイメージング材料に使用される還元剤の量は、脂肪族カルボン酸銀塩（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モル乃至１０モル、好ましくは０．１モル乃至３モルが適当である。又この量の範囲内において、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。
【０１３７】
尚、本発明において、塗布銀量は銀塩光熱写真イメージング材料の目的に応じた適量を選ぶことが好ましいが、医療用画像を目的とする場合には、０．６〜２．５ｇ／ｍ²が好ましく、更には１．０〜１．７ｇ／ｍ²が好ましい。当該塗布銀量の内、ハロゲン化銀に由来するものは全銀量に対して２〜１８％を占めることが好ましく、更には３〜１５％がより好ましい。
【０１３８】
又本発明において、０．０１μｍ以上（球相当換算粒径）のハロゲン化銀粒子の塗布密度は１×１０¹⁴〜１×１０¹⁸個／ｍ²が好ましく、更に１×１０¹⁵〜１×１０¹⁷個／ｍ²が好ましい。
（感光性ハロゲン化銀）
本発明における感光性ハロゲン化銀粒子（単にハロゲン化銀粒子ともいう）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来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、且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ときに、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いう。
【０１３９】
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（ＰａｕｌＭｏｎｔｅｌ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。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、沃化銀の何れであってもよい。
【０１４０】
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。
【０１４１】
ハロゲン化銀粒子は、画像形成後の白濁や色調（黄色味）を低く抑えるため、及び良好な画質を得るために平均粒径が小さい方が好ましく、平均粒径は０．０２μｍ未満の粒子を計測の対象外としたときの値として、０．０３５μｍ以上、０．０５５μｍ以下が好ましい。尚ここでいう粒径とは、ハロゲン化銀粒子が立方体或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いう。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ときの直径をいう。
【０１４２】
本発明において、ハロゲン化銀粒子は単分散であることが好ましい。ここでいう単分散とは、下記式で求められる粒径の変動係数が３０％以下をいう。好ましくは２０％以下であり、更に好ましくは１５％以下である。
【０１４３】
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。
【０１４４】
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がよい。これらは米国特許第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。
【０１４５】
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銀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。
【０１４６】
本発明に用いられるハロゲン化銀粒子は、該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２０００〜４００００、更には５０００〜２５０００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ることができる。
【０１４７】
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。
【０１４８】
本発明に用いられるハロゲン化銀粒子は、該粒子形成時に下記の一般式で示される化合物を用いることが好ましい。
【０１４９】
一般式
ＹＯ（ＣＨ₂ＣＨ₂Ｏ）_m（ＣＨ（ＣＨ₃）ＣＨ₂Ｏ）_p（ＣＨ₂ＣＨ₂Ｏ）_nＹ
式中、Ｙは水素原子、−ＳＯ₃Ｍ、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、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。
【０１５０】
上記の一般式で表される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きたものであり、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。上記一般式で表される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。
【０１５１】
上記一般式で表される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。
【０１５２】
上記一般式で表される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若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％に亘る時間で存在せしめるのが好ましく、更に好ましくは７０％以上に亘る時間で存在せしめる。上記一般式で表される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。
【０１５３】
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（例えば、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前記温度範囲内で制御するのが好ましい。
【０１５４】
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／Ｌ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。
【０１５５】
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。
【０１５６】
本発明に用いられるハロゲン化銀粒子はいかなる方法で感光層に添加されてもよく、このとき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。
【０１５７】
本発明に用いられる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、英国特許第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。
【０１５８】
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第４，００９，０３９号、同３，４５７，０７５号、同４，００３，７４９号、英国特許第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マイド、セチルエチルジメチルアンモニウムブロマイド、トリメチルベンジルアンモニウムブロマイドの様なオニウムハライド類、例えばヨードフォルム、ブロモフォルム、四塩化炭素、２−ブロム−２−メチルプロパン等のハロゲン化炭化水素類、Ｎ−ブロム琥珀酸イミド、Ｎ−ブロムフタルイミド、Ｎ−ブロムアセトアミド等の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−ブロム酢酸、２−ブロムエタノール、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。
【０１５９】
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。
【０１６０】
本発明に用いられるハロゲン化銀粒子には、元素周期律表の６族から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種類でも同種或い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モルから、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。本発明においては、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。
【０１６１】
一般式〔ＭＬ₆〕^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、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（弗素イオン、塩素イオン、臭素イオン、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、又異なっていてもよい。
【０１６２】
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、数回に渡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号等に記載されてい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。
【０１６３】
これらの金属化合物は、水或いは適当な有機溶媒（例えば、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ＮａＣｌ、ＫＣｌ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、或いは銀塩溶液とハライド溶液が同時に混合されるとき第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、或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ＮａＣｌ、ＫＣｌ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。
【０１６４】
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。
【０１６５】
本発明の銀塩光熱写真ドライイメージング材料は、熱現像処理にて写真画像を形成するもので、脂肪族カルボン酸銀塩、感光性ハロゲン化銀粒子、架橋剤、還元剤及び必要に応じて銀の色調を調整する色調剤を通常（有機）バインダーマトリックス中に分散した状態で含有していることが好ましい。
（色調剤）
好適な色調剤の例は、ＲＤ１７０２９号、米国特許第４，１２３，２８２号、同３，９９４，７３２号、同３，８４６，１３６号及び同４，０２１，２４９号に開示されている。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み合わせである。
【０１６６】
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やすいと言われている。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。
【０１６７】
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ｈ_abにより求められる。色相角ｈ_ab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^*を用いて次の式によって求める。
【０１６８】
ｈ_ab＝ｔａｎ−１（ｂ^*／ａ^*）
本発明において、好ましい色相角ｈ_abの範囲は１８０°＜ｈ_ab＜２７０°であり、更に好ましくは２００°＜ｈ_ab＜２７０°、最も好ましくは２２０°＜ｈ_ab＜２６０°である。
【０１６９】
本発明においては、銀塩光熱写真ドライイメージング材料の表面層に（感光層側、又支持体をはさみ感光層の反対側に非感光層を設けた場合にも）、現像前の取り扱いや熱現像後の画像の傷つ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。
【０１７０】
マット剤の材質は、有機物及び無機物の何れでもよい。例えば、無機物としては、スイス特許第３３０，１５８号等に記載のシリカ、仏国特許第１，２９６，９９５号等に記載のガラス粉、英国特許第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、米国特許第２，３２２，０３７号等に記載の澱粉、ベルギー特許第６２５，４５１号や英国特許第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、スイス特許第３３０，１５８号等に記載のポリスチレン或いはポリメタアクリレート、米国特許第３，０７９，２５７号等に記載のポリアクリロニトリル、米国特許第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。
【０１７１】
マット剤は平均粒径が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。
【０１７２】
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。
（粒径の標準偏差）／（粒径の平均値）×１００
本発明に係る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あってもよいし、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。
（支持体）
本発明の銀塩光熱写真ドライイメージング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（例えば、アルミニウム）等が挙げられるが、情報記録材料としての取り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ドライイメージング材料における支持体としては、プラスチックフィルム（例えば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、本発明においては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。
【０１７３】
本発明においては帯電性を改良するために、金属酸化物及び／又は導電性ポリマーなどの導電性化合物を構成層中に含ませることができる。これらは何れの層に含有させてもよいが、好ましくは下引層、バッキング層、感光層と下引の間の層などに含まれる。本発明においては米国特許第５，２４４，７７３号カラム１４〜２０に記載された導電性化合物が好ましく用いられる。
（銀塩光熱写真ドライイメージング材料の形成）
本発明の銀塩光熱写真ドライイメージング材料は、支持体上に少なくとも１層の感光層を有している。支持体の上に感光層のみを形成してもよいが、感光層の上に少なくとも一層の非感光層を形成するのが好ましい。例えば、感光層を保護する目的で感光層の上には保護層が、又支持体の反対の面には感光材料間の、或いは感光材料ロールにおいてくっつきを防止する為に、バックコート層が設けられるのが好ましい。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熱現像層よりもガラス転位点が高く、擦り傷や、変形の生じにくいポリマー、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、前記のバインダーのなかから選ばれる。尚、階調調整等のために、感光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。
【０１７４】
本発明の銀塩光熱写真ドライイメージング材料においては、感光層を透過する光の量又は波長分布を制御するために感光層と同じ側又は反対の側にフィルター層を形成するか、感光層に染料又は顔料を含有させることが好ましい。
【０１７５】
用いられる染料としては、感光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。
【０１７６】
例えば、本発明の銀塩光熱写真ドライイメージング材料を赤外光による画像記録材料とする場合には、特願平１１−２５５５５７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（本明細書ではチオピリリウムスクアリリウム染料と呼ぶ）及びピリリウム核を有するスクアリリウム染料（本明細書ではピリリウムスクアリリウム染料と呼ぶ）、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。
【０１７７】
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。以下本明細書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よぶ。
【０１７８】
尚、染料としては特開平８−２０１９５９号の化合物も好ましい。
本発明の銀塩光熱写真ドライイメージング材料は、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、それら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されることが好ましい。ここで「複数同時に重層塗布」とは、各構成層（例えば感光層、保護層）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、乾燥の繰り返しをするのではなく、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うることを意味する。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。
【０１７９】
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。これらのうち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。この塗布方法は感光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、下引きとともに塗布する場合についても同様である。
【０１８０】
尚、本発明において、塗布銀量は銀塩光熱写真イメージング材料の目的に応じた適量を選ぶことが好ましいが、医療用画像を目的とする場合には、０．６〜２．５ｇ／ｍ²が好ましい。更には１．０〜１．７ｇ／ｍ²が好ましい。当該塗布銀量の内、ハロゲン化銀に由来するものは全銀量に対して２〜１８％を占めることが好ましい、更には３〜１５％がより好ましい。
【０１８１】
又本発明において、０．０１μｍ以上（球相当換算粒径）のハロゲン化銀粒子の塗布密度は１×１０¹⁴〜１×１０¹⁸個／ｍ²が好ましい。更には、１×１０¹⁵〜１×１０¹⁷個／ｍ²が好ましい。
【０１８２】
更に本発明の脂肪族カルボン酸銀塩の塗布密度は、０．０１μｍ以上（球相当換算粒径）のハロゲン化銀粒子１個当たり、１０^-17〜１０^-15ｇ、更には１０^-16〜１０^-14ｇが好ましい。
【０１８３】
上記のような範囲内の条件において塗布した場合には、一定塗布銀量当たりの銀画像の光学的最高濃度、即ち、銀被覆量（カバーリング・パワー）及び銀画像の色調等の観点から好ましい結果が得られる。
（画像記録方法）
本発明において、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、像様に露光した銀塩光熱写真ドライイメージング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（例えば、約８０〜２００℃、好ましくは約１００〜２００℃）で十分な時間（一般には約１秒〜約２分間）、銀塩光熱写真ドライイメージング材料を加熱することにより現像することができる。加熱温度が８０℃以下では短時間に十分な画像濃度が得られず、又２００℃以上では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。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。
【０１８４】
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ドライイメージング材料は、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。
【０１８５】
本発明の銀塩光熱写真ドライイメージング材料の露光は、当該感光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（７８０ｎｍ、８２０ｎｍ）がより好ましく用いられる。
【０１８６】
本発明において、露光はレーザ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光のなす角が実質的に垂直になることがないレーザ走査露光機を用いる方法が挙げられる。
【０１８７】
ここで、「実質的に垂直になることがない」とは、レーザ走査中に最も垂直に近い角度として、好ましくは５５〜８８度、より好ましくは６０〜８６度、更に好ましくは６５〜８４度、最も好ましくは７０〜８２度であることをいう。
【０１８８】
レーザ光が、感光材料に走査されるときの感光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係る画質劣化を減じることが出来る。
【０１８９】
又、第２の方法として、本発明における露光は縦マルチである走査レーザ光を発するレーザ走査露光機を用いて行うことも好ましい。縦単一モードの走査レーザ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。
【０１９０】
縦マルチ化するには、合波による戻り光を利用する、高周波重畳をか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。
【０１９１】
尚、上述した第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としては、一般によく知られている、ルビーレーザ、ＹＡＧレーザ、ガラスレーザ等の固体レーザ；ＨｅＮｅレーザ、Ａｒイオンレーザ、Ｋｒイオンレーザ、ＣＯ₂レーザ、ＣＯレーザ、ＨｅＣｄレーザ、Ｎ₂レーザ、エキシマーレーザ等の気体レーザ；ＩｎＧａＰレーザ、ＡｌＧａＡｓレーザ、ＧａＡｓＰレーザ、ＩｎＧａＡｓレーザ、ＩｎＡｓＰレーザ、ＣｄＳｎＰ₂レーザ、ＧａＳｂレーザ等の半導体レーザ；化学レーザ、色素レーザ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の半導体レーザを用いるのが好ましい。尚、レーザ・イメージャやレーザ・イメージセッタで使用されるレーザにおいて、銀塩光熱写真ドライイメージング材料に走査されるとき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、レーザ光走査速度は銀塩光熱写真ドライイメージング材料固有のレーザ発振波長における感度とレーザパワーによって、感光材料毎に最適な値に設定することができる。
【０１９２】
【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。
【０１９３】
実施例１
《写真用支持体の作製》
濃度０．１７０に青色着色したポリエチレンテレフタレートフィルムベース（厚み１７５μｍ）の片方の面に、０．５ｋＶ・Ａ・ｍｉｎ／ｍ²のコロナ放電処理を施した後、その上に下記の下引塗布液Ａを用いて下引層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／ｍ²のコロナ放電処理を施した後、その上に下記の下引塗布液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なるフィルム搬送装置を有する熱処理式オーブンの中で１３０℃にて１５分熱処理を行った。
（下引塗布液Ａ）
ｎ−ブチルアクリレート３０質量％、ｔ−ブチルアクリレート２０質量％、スチレン２５質量％及び２−ヒドロキシエチルアクリレート２５質量％の共重合体ラテックス液（固形分３０％）２７０ｇ、界面活性剤（ＵＬ−１）０．６ｇ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（株）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。
（コロイド状酸化スズ分散液の調製）
塩化第２スズ水和物６５ｇを、水／エタノール混合溶液２０００ｍｌに溶解して均一溶液を調製した。次いで、これを煮沸し共沈殿物を得た。生成した沈殿物をデカンテーションにより取り出し、蒸留水にて数回水洗した。沈殿物を洗浄した蒸留水中に硝酸銀を滴下し、塩素イオンの反応がないことを確認後、洗浄した沈殿物に蒸留水を添加し、全量を２０００ｍｌとする。更に、３０％アンモニア水を４０ｍｌ添加し、水溶液を加温して、容量が４７０ｍｌになるまで濃縮してコロイド状酸化スズ分散液を調製した。
（下引塗布液Ｂ）
前記コロイド状酸化スズ分散液３７．５ｇ、ｎ−ブチルアクリレート２０質量％、ｔ−ブチルアクリレート３０質量％、スチレン２７質量％及び２−ヒドロキシエチルアクリレート２８質量％の共重合体ラテックス液（固形分３０％）３．７ｇ、ｎ−ブチルアクリレート４０質量％、スチレン２０質量％、グリシジルメタクリレート４０質量％の共重合体ラテックス液（固形分３０％）１４．８ｇと界面活性剤（ＵＬ−１）０．１ｇを混合し、水で１０００ｍｌに仕上げて下引塗布液Ｂとした。
【０１９４】
【化１８】

【０１９５】
《バック面側塗布》
メチルエチルケトン（ＭＥＫ）８３０ｇを攪拌しながら、セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社、ＣＡＢ３８１−２０）８４．２ｇ及びポリエステル樹脂（Ｂｏｓｔｉｃ社、ＶｉｔｅｌＰＥ２２００Ｂ）４．５ｇを添加し、溶解した。次に、溶解した液に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Ｆ系活性剤（旭硝子社、サーフロンＫＨ４０）４．５ｇとＦ系活性剤（大日本インク社、メガファッグＦ１２０Ｋ）２．３ｇを添加して、溶解するまで十分に攪拌を行った。最後に、ＭＥＫに１質量％の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、シロイド６４Ｘ６０００）を７５ｇ添加、攪拌しバック面側用の塗布液を調製した。
【０１９６】
【化１９】

【０１９７】
このように調製したバック面塗布液を、乾燥膜厚が３．５μｍになるように押し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。
《感光性ハロゲン化銀乳剤Ａの調製》
Ａ１
フェニルカルバモイル化ゼラチン ８８．３ｇ
化合物（Ａ）（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
Ｂ１
０．６７ｍｏｌ／Ｌ硝酸銀水溶液 ２６３５ｍｌ
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
Ｄ１
臭化カリウム １５４．９ｇ
沃化カリウム ４．４１ｇ
塩化イリジウム（１％溶液） ０．９３ｍｌ
水で１９８２ｍｌに仕上げる
Ｅ１
０．４ｍｏｌ／Ｌ臭化カリウム水溶液 下記銀電位制御量
Ｆ１
水酸化カリウム ０．７１ｇ
水で２０ｍｌに仕上げる
Ｇ１
５６％酢酸水溶液 １８．０ｍｌ
Ｈ１
無水炭酸ナトリウム １．７２ｇ
水で１５１ｍｌに仕上げる
化合物（Ａ）：

特公昭５８−５８２８８号、同５８−５８２８９号に示される混合攪拌機を用いて溶液（Ａ１）に、溶液（Ｂ１）の１／４量及び溶液（Ｃ１）全量を温度３９℃、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３９℃、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分間攪拌した後、４０℃に降温し、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、攪拌後、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、攪拌後、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分攪拌した。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、乳剤を得た。
【０１９８】
この乳剤は平均粒子サイズ０．０５３μｍ、粒子サイズの変動係数１２％、〔１００〕面比率９２％の単分散立方体沃臭化銀粒子であった。
【０１９９】
次に上記乳剤に硫黄増感剤Ｓ−５（０．５％メタノール溶液）２４０ｍｌを加え、更にこの増感剤の１／２０モル相当の金増感剤Ａｕ−５を添加し、５５℃にて１２０分間攪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Ａとする。
【０２００】
【化２０】

【０２０１】
《粉末脂肪族カルボン酸銀塩Ａ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１．５ｍｏｌ／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。該脂肪酸ナトリウム溶液の温度を５５℃に保ったまま、４５．３ｇの上記の感光性ハロゲン化銀乳剤Ａと純水４５０ｍｌを添加し５分間攪拌した。
【０２０２】
次に１ｍｏｌ／Ｌの硝酸銀溶液７０２．６ｍｌを２分間かけて添加し、１０分間攪拌し脂肪族カルボン酸銀塩分散物を得た。その後、得られた脂肪族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攪拌後、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（株式会社セイシン企業製）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Ａを得た。脂肪族カルボン酸銀塩組成物の含水率測定には赤外線水分計を使用した。又、ベヘン酸比率は５４質量％であった。
《粉末脂肪族カルボン酸銀塩Ｂの調製》
ベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇとし、溶解温度を９０℃にした以外は粉末脂肪族カルボン酸銀塩Ａと同様にして粉末脂肪族カルボン酸銀塩Ｂを作製した。ベヘン酸比率は８５質量％であった。
《粉末脂肪族カルボン酸銀塩Ｃの調製》
ベヘン酸（２質量％はアラキジン酸を含有していた）２５９．３ｇを使用し、溶解温度を９０℃にした以外は粉末脂肪族カルボン酸銀塩Ａと同様にして粉末脂肪族カルボン酸銀塩Ｃを作製した。ベヘン酸比率は９８質量％であった。
《粉末脂肪族カルボン酸銀塩Ｄの調製》
ベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇとし、溶解温度を９０℃、水酸化ナトリウムを水酸化カリウムに変更した以外は粉末脂肪族カルボン酸銀塩Ａと同様にして粉末脂肪族カルボン酸銀塩Ｄを作製した。ベヘン酸比率は８５質量％であった。
《粉末脂肪族カルボン酸銀塩Ｅの調製》
ベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇとし、溶解温度を９０℃、水酸化ナトリウムを水酸化ナトリウム：水酸化カリウム＝１：９（モル比）に変更した以外は粉末脂肪族カルボン酸銀塩Ａと同様にして粉末脂肪族カルボン酸銀塩Ｅを作製した。ベヘン酸比率は８５質量％であった。
《粉末脂肪族カルボン酸銀塩Ｆの調製》
ベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇとし、溶解温度を９０℃、水酸化ナトリウムを水酸化ナトリウム：水酸化カリウム＝７５：２５（モル比）に変更した以外は粉末脂肪族カルボン酸銀塩Ａと同様にして粉末脂肪族カルボン酸銀塩Ｆを作製した。ベヘン酸比率は８５質量％であった。
《予備分散液Ａ〜Ｆの調製》
ポリビニルブチラール樹脂（ソルーシア社製、Ｂ−７９）１４．５７ｇをＭＥＫ１４５７ｇに溶解し、ＶＭＡ−ＧＥＴＺＭＡＮＮ社製ディゾルバＤＩＳＰＥＲＭＡＴ ＣＡ−４０Ｍ型にて攪拌しながら、粉末脂肪族カルボン酸銀塩Ａ、５００ｇを徐々に添加して十分に混合することにより予備分散液Ａを調製した。
【０２０３】
粉末脂肪族カルボン酸銀塩Ａの代わりに、粉末脂肪族カルボン酸銀塩Ｂ〜Ｆを用いる他は、全く同様にして予備分散液Ｂ〜Ｆを調製した。
《感光性乳剤分散液Ａ〜Ｆの調製》
予備分散液Ａ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（東レ製トレセラム）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／ｓにて分散を行なうことにより感光性乳剤分散液Ａを調製した。
【０２０４】
予備分散液Ａの代わりに、予備分散液Ｂ〜Ｆを用いる他は、全く同様にして感光性乳剤分散液Ｂ〜Ｆを調製した。
《安定剤液の調製》
１．０ｇの安定剤１、０．３１ｇの酢酸カリウムをメタノール４．９７ｇに溶解し安定剤液を調製した。
《赤外増感色素液Ａの調製》
１９．２ｍｇの赤外増感色素１、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Ａを調製した。
《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）−３，５，５−トリメチルヘキサン（現像剤Ａ）を２７．９８ｇ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。
《添加液ｂの調製》
３．５６ｇのカブリ防止剤２、３．４３ｇのフタラジンをＭＥＫ４０．９ｇに溶解し、添加液ｂとした。
《感光層塗布液Ａの調製》
不活性気体雰囲気下（窒素９７％）において、前記感光性乳剤分散液Ａ（５０ｇ）及びＭＥＫ１５．１１ｇを攪拌しながら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時間攪拌した。更に臭化カルシウム（１０％メタノール溶液）４９４μｌを添加して２０分攪拌した。続いて、安定剤液１６７ｍｌを添加して１０分間攪拌した後、１．３２ｇの前記赤外増感色素液Ａを添加して１時間攪拌した。その後、温度を１３℃まで降温して更に３０分攪拌した。１３℃に保温したまま、ポリビニルブチラール樹脂（Ｂ−７９、ソルーシア社製）１３．３１ｇを添加して３０分攪拌した後、テトラクロロフタル酸（９．４質量％ＭＥＫ溶液）１．０８４ｇを添加して１５分間攪拌した。更に攪拌を続けながら、１２．４３ｇの添加液ａ、１．６ｍｌのＤｅｓｍｏｄｕｒＮ３３００／モーベイ社製の脂肪族イソシアネート（１０％ＭＥＫ溶液）、４．２７ｇの添加液ｂを順次添加し攪拌することにより感光層塗布液Ａを得た。
《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、７．５ｇのＣＡＢ１７１−１５）をＭＥＫ４２．５ｇに溶解し、その中に、炭酸カルシウム（Ｓｐｅｃｉａｌｉｔｙ Ｍｉｎｅｒａｌｓ社、Ｓｕｐｅｒ−Ｐｆｌｅｘ２００）５ｇを添加し、ディゾルバ型ホモジナイザにて８０００ｒｐｍで３０分分散し、マット剤分散液を調製した。
《表面保護層塗布液の調製》
ＭＥＫ８６５ｇを攪拌しながら、セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社、ＣＡＢ１７１−１５）を９６ｇ、ポリメチルメタクリル酸（ローム＆ハース社、パラロイドＡ−２１）を４．５ｇ、ビニルスルホン化合物（ＶＳＣ）を１．５ｇ、ベンズトリアゾールを１．０ｇ、Ｆ系活性剤（旭硝子社、サーフロンＫＨ４０）を１．０ｇ添加し溶解した。次に上記マット剤分散液３０ｇを添加して攪拌し、表面保護層塗布液を調製した。
【０２０５】
【化２１】

【０２０６】
《銀塩光熱写真ドライイメージング材料試料１０１の作製》
感光層塗布液Ａ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を行った。塗布は感光層が塗布銀量１．５ｇ／ｍ²、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、銀塩光熱写真ドライイメージング材料試料１０１（表２では単に試料１０１とする）を作製した。
【０２０７】
感光層塗布液中の感光性乳剤分散液、感光層のバインダー及び還元剤種類を表２に記載のように変更した他は試料１０１と同様にして表２記載の様に試料１０２以下を作製した。
【０２０８】
測定の結果は、感度（未露光部分よりも１．０高い濃度を与える露光量の比の逆数）及びカブリで評価し、試料１０１の感度を１００とする相対値で表２に示した。
《評価》
〈熱転移点温度の測定〉
テフロン（Ｒ）板の上に、前記と同一組成の感光層塗布液及び表面保護層塗布液を、各々ワイヤーバーを用いて同一条件となるように塗布、乾燥させた後、最高濃度が得られる条件で同様に露光、現像した後、テフロン（Ｒ）板より塗設した構成層を剥離した。剥離した試料約１０ｍｇをアルミ製のパンに装填し、示差走査型熱量計（セイコー電子社製、ＥＸＳＴＡＲ６０００）を用い、ＪＩＳ Ｋ７１２１に従って各試料の熱転移点温度を測定した。測定の際の昇温条件としては、０〜２００℃までは１０℃／ｍｉｎで昇温し、０℃までの冷却は２０℃／ｍｉｎで行い、この操作を２回繰り返して、熱転移点温度を求めた。
〈カブリ濃度変動率の測定〉
上記感度測定と同様の方法で熱現像処理を行った試料を４５℃、５５％ＲＨの環境下、市販の白色蛍光灯を試料表面における照度が５００ｌｕｘとなるように配置し、３日間連続照射を施した。蛍光灯照射済み試料の最小濃度（Ｄ₂）と蛍光灯未照射試料の最小濃度（Ｄ₁）をそれぞれ測定し、以下の式よりカブリ濃度変動率（％）を算出した。
【０２０９】
カブリ濃度変動率＝（Ｄ₂−Ｄ₁）／Ｄ₁×１００（％）
〈画像保存性の評価〉
上記感度測定と同様の方法で熱現像処理を行った試料を２５℃及び４５℃の環境下に３日間放置した後、最高濃度の変化を測定し、下記により画像濃度変化率を測定し、それを画像保存性の尺度とした。
【０２１０】
画像濃度変化率＝４５℃保存試料の最高濃度／２５℃保存試料の最高濃度×１００（％）
〈経時保存性の評価〉
得られた試料を下記に示す２つの条件で１０日間保存した後、それぞれ感度の測定と同一方法で露光、現像を行った後、得られた画像の感度評価を行い、各試料の条件Ａに対する条件Ｂの感度変化率を下記より求め、経時保存性の尺度とした。
【０２１１】
条件Ａ：２５℃、５５％ＲＨ
条件Ｂ：４０℃、８０％ＲＨ
感度変化率＝条件Ｂにおける感度／条件Ａにおける感度×１００（％）
〈色相角の測定〉
色相角ｈ_abの測定は、現像処理後試料の最小濃度部及び光学濃度１．０の部分をＪＩＳ Ｚ８７２０の常用光源Ｄ６５を測色用の光源として、２°視野で分光測色計ＣＭ−５０８ｄ（ミノルタ社製）を用いて測定して求めた。
〈フィルター補足物（フィルムからの昇華物）〉
フィルム濃度が３．５以上となるように露光を与えたフィルムを１００００枚熱現像した後、現像機内のフィルターに補足された補足物の質量により４段階に評価した。
【０２１２】
１・・・非常に多い
２・・・多い
３・・・補足物はあるが少ない
４・・・補足物は非常に少ない
【０２１３】
【表２】

【０２１４】
※１：感光性乳剤分散液
※２：感光層のバインダー
※３：還元剤種類
※４：感光層の熱転移点温度（℃）
※５：カブリ濃度変動率（％）
※６：フィルター補足物
※７：色相角ｈ_ab：最小濃度部
※８：色相角ｈ_ab：Ｄ＝１．０部
表２から明らかなように、本発明の銀塩光熱写真ドライイメージング材料は、比較例に比べ、高感度でありながら、カブリが低く、現像処理後の画像保存性及び経時保存性に優れ、フィルムからの昇華物も非常に少ないことが判る。又、本発明の試料はＪＩＳ Ｚ８７２９で規定される色相角の値も１８０°を越え、且つ２７０°未満であり、冷調な画像調子を有し、診断画像として適切な出力画像が得られることが判った。
【０２１５】
実施例２
以下に示す以外は実施例１と同様にして、銀塩光熱写真ドライイメージング材料試料を作製した。
《粉末脂肪族カルボン酸銀塩Ｇの調製》
４７２０ｍｌの純水にベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇを９０℃で溶解した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム：水酸化カリウム水溶液（モル比＝１：９）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、ｔ−ブチルアルコール３４７ｍｌを添加し２０分間攪拌した後、実施例１で得られた感光性ハロゲン化銀乳剤Ａ（４５．３ｇ）と純水４５０ｍｌを添加し５分間攪拌した。
【０２１６】
その他は実施例１の粉末脂肪族カルボン酸銀塩Ａと同様にして、粉末脂肪族カルボン酸銀塩Ｇを調製した。
《粉末脂肪族カルボン酸銀塩Ｈの調製》
４７２０ｍｌの純水にベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇ、ｉｓｏ−アラキジン酸１７．０ｇを９０℃で溶解した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム：水酸化カリウム水溶液（モル比＝１：９）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、実施例１で得られた感光性ハロゲン化銀乳剤Ａ（４５．３ｇ）と純水４５０ｍｌを添加し５分間攪拌した。
【０２１７】
その他は実施例１の粉末脂肪族カルボン酸銀塩Ａと同様にして、粉末脂肪族カルボン酸銀塩Ｈを調製した。
《粉末脂肪族カルボン酸銀塩Ｉの調製》
４７２０ｍｌの純水にベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇ、オレイン酸６．０ｇを９０℃で溶解した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム：水酸化カリウム水溶液（モル比＝１：９）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、実施例１で得られた感光性ハロゲン化銀乳剤Ａ（４５．３ｇ）と純水４５０ｍｌを添加し５分間攪拌した。
【０２１８】
その他は実施例１の粉末脂肪族カルボン酸銀塩Ａと同様にして、粉末脂肪族カルボン酸銀塩Ｉを調製した。
《粉末脂肪族カルボン酸銀塩Ｊの調製》
４７２０ｍｌの純水にベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇ、及びポリビニルアルコール１．５ｇ（クラレ社製ＰＶＡ―２０５）を９０℃で溶解した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム：水酸化カリウム水溶液（モル比＝１：９）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、実施例１で得られた感光性ハロゲン化銀乳剤Ａ（４５．３ｇ）と純水４５０ｍｌを添加し５分間攪拌した。
【０２１９】
その他は実施例１の粉末脂肪族カルボン酸銀塩Ａと同様にして、粉末脂肪族カルボン酸銀塩Ｊを調製した。
《粉末脂肪族カルボン酸銀塩Ｋの調製》
４７２０ｍｌの純水にベヘン酸２１７ｇ、アラキジン酸２０．０ｇ、ステアリン酸１７．３ｇを９０℃で溶解した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム：水酸化カリウム水溶液（モル比＝１：９）５４０．２ｍｌを添加し濃硝酸６．９ｍｌを加えた後ｎ−ブチルアクリレート３０質量％、ｔ−ブチルアクリレート２０質量％、スチレン２５質量％及び２−ヒドロキシエチルアクリレート２５質量％の共重合体ラテックス液（固形分３０％）５０ｇを添加し、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、実施例１で得られた感光性ハロゲン化銀乳剤Ａ（４５．３ｇ）と純水４５０ｍｌを添加し５分間攪拌した。
【０２２０】
その他は実施例１の粉末脂肪族カルボン酸銀塩Ａと同様にして、粉末脂肪族カルボン酸銀塩Ｋを調製した。
《予備分散液Ｇ〜Ｋの調製》
粉末脂肪族カルボン酸銀塩Ｇ〜Ｋに変更する他は、実施例１と同様にして調製した。
《感光性乳剤分散液Ｇ〜Ｋの調製》
予備分散液Ｇ〜Ｋに変更する他は、実施例１と同様にして調製した。
《感光層塗布液Ｇの調製》
実施例１の感光層塗布液Ａと同様にして、感光性乳剤分散液Ｇを用いて感光層塗布液Ｇを調製した。
《銀塩光熱写真ドライイメージング材料試料２０１〜２０５の作製》
感光層塗布液Ｇと実施例１の表面保護層塗布液を用いて、実施例１と同様にして試料２０１を作製した。
【０２２１】
感光層塗布液中の感光性乳剤分散液、感光層のバインダー及び還元剤種類を表３に記載したものに変更した他は、試料２０１と同様にして試料２０２〜２０５を作製した。
〈脂肪族カルボン酸銀塩の粒径と厚さの測定〉
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）を用いて直接倍率５０００倍で撮影し、スキャナーにてネガをデジタル画像として取り込み、画像処理装置ＬＵＺＥＸIII（ニコレ社製）を用いて３００個の粒径を測定し、この平均値を求めた。
【０２２２】
次に厚さを求めるため、支持体上に塗布された感光層を接着剤により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の超薄切片を作製した。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上記透過型電子顕微鏡を用いて、倍率５，０００〜４０，０００で明視野像を観察し画像をフィルムに記録した。この画像を画像処理装置ＬＵＺＥＸIII（ニコレ社製）を用いて３００個の厚さを測定し、この平均値を求めた。
【０２２３】
露光、現像処理及び各種の評価は実施例１と同様にして行った。
【０２２４】
【表３】

【０２２５】
※１：感光性乳剤分散液
※２：脂肪族カルボン酸銀粒径（μｍ）
※３：脂肪族カルボン酸銀膜厚（μｍ）
※４：感光層のバインダー
※５：還元剤種類
※６：感光層の熱転移点温度（℃）
※７：カブリ濃度変動率（％）
※８：フィルター補足物
※９：色相角ｈ_ab：最小濃度部
※１０：色相角ｈ_ab：Ｄ＝１．０部
表３から明らかなように、本発明の銀塩光熱写真ドライイメージング材料は、比較例に比べ高感度でありながら、カブリが低く、現像処理後の画像保存性及び経時保存性に優れ、フィルムからの昇華物も非常に少ないことが判る。又、本発明の試料はＪＩＳ Ｚ８７２９で規定される色相角の値も１８０°を越え、且つ２７０°未満であり、冷調な画像調子を有し、診断画像として適切な出力画像が得られることが判った。
【０２２６】
実施例３
《銀塩光熱写真ドライイメージング材料試料３０１の作製》
公知のエクストルージョン型コーターを用いて、感光層２層及び保護層１層の計３層を同時に重層塗布することにより３０１を作製した。塗布は感光層（上層）の塗布銀量が０．９ｇ／ｍ²、感光層（下層）の塗布銀量が０．６ｇ／ｍ²、表面保護層は乾燥膜厚で２．５μｍになる様にして行った。その後、乾燥温度５０℃、露点温度１０℃の乾燥風を用いて、１０分間乾燥を行った。
【０２２７】
感光層塗布液中の感光性乳剤分散液、還元剤種類及び感光層のバインダーを表４に記載したものに変更した以外は３０１の作製と同様にして試料３０２〜３０８を作製した。
【０２２８】
露光、現像処理及び各種の評価は実施例１と同様にして行った。
【０２２９】
【表４】

【０２３０】
※１：感光性乳剤分散液
※２：感光層のバインダー
※３：還元剤種類
※４：カブリ濃度変動率（％）
※５：フィルター補足物
※６：色相角ｈ_ab：最小濃度部
※７：色相角ｈ_ab：Ｄ＝１．０部
表４から明らかなように、本発明の銀塩光熱写真ドライイメージング材料は感光層重層系でも比較例に比べ高感度でありながら、カブリが低く、現像処理後の画像保存性及び経時保存性に優れ、フィルムからの昇華物も非常に少ないことが判る。又、本発明の試料はＪＩＳ Ｚ８７２９で規定される色相角の値も１８０°を越え、且つ２７０°未満であり、冷調な画像調子を有し、診断画像として適切な出力画像が得られることが判った。
【０２３１】
【発明の効果】
本発明によれば、高感度、低カブリ、且つ生保存性、経時保存性に優れ、フィルムからの昇華物も非常に少ない銀塩光熱写真ドライイメージング材料をその画像記録方法と共に提供することができるという顕著に優れた効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silver salt photothermographic dry imaging material and an image recording method thereof.
[0002]
[Prior art]
Conventionally, in the fields of medical treatment and printing plate making, waste liquid from wet processing of image forming materials has been a problem in terms of workability. In recent years, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental conservation and space saving. ing.
[0003]
For this reason, there has been a need for a technology related to photothermographic materials for photographic technology that enables efficient exposure, such as laser imagers and laser imagesetters, and that can form clear black images with high resolution. Yes.
[0004]
As such a technique, for example, D.I. Morgan and B.M. U.S. Pat. Nos. 3,152,904, 3,487,075 by Shely or D.C. H. As described in "Dry Silver Photographic Materials" by Klosterboer (Handbook of Imaging Materials, Organics of Markel, Inc., page 48, 1991) and the like. A silver salt photothermographic dry imaging material (also simply referred to as a photosensitive material) containing a silver salt, a photosensitive silver halide and a reducing agent is known. Since this silver salt photothermographic dry imaging material does not use any solution processing chemicals, it is possible to provide a user with a simpler system that does not damage the environment.
[0005]
By the way, these silver salt photothermographic dry imaging materials use photosensitive silver halide grains installed in the photosensitive layer as a photosensor, use organic silver salt as a source of silver ions, and usually 80 to 140 depending on a built-in reducing agent. It is characterized in that an image is formed by heat development at 0 ° C. and fixing is not performed.
[0006]
However, since the silver salt photothermographic dry imaging material contains an organic silver salt, photosensitive silver halide grains and a reducing agent, there is a problem that fog is likely to occur during the storage period before heat development. In addition, after exposure, usually heat development is performed at 80 to 250 ° C., and fixing is not performed. Therefore, even after heat development, all or part of silver halide, organic silver salt and reducing agent coexist and remain for a long time. However, there is a problem that metallic silver is generated by heat and light, and the image quality such as the color tone of the silver image is easily changed.
[0007]
Techniques for solving these problems are disclosed in JP-A-6-208192, JP-A-8-267934, US Pat. No. 5,714,311 and documents cited in these patent documents. However, although these disclosed technologies have some effects, they are not yet sufficient as technologies for satisfying the level required in the market.
[0008]
On the other hand, there is a demand for higher image quality as an eternal theme of silver salt photothermographic dry imaging materials. In particular, in the field of medical images, there is a demand for higher image quality that enables more accurate diagnosis. In addition, in the silver salt photothermographic dry imaging material system, there is a problem that carboxylic acid liberated silver by heat development or a sublimable substance adheres to the inside of the machine or the developing roll, so that the material in the dry imaging material is not released as much as possible. Silver salt photothermographic dry imaging materials have been desired.
[0009]
[Problems to be solved by the invention]
Therefore, the present invention has been made in view of the above circumstances, and its purpose is to maintain the fog and sensitivity, and to be excellent in raw storability and stability of a silver image after heat development, and has little contamination in the developing machine. A silver salt photothermographic dry imaging material and an image recording method thereof are provided.
[0010]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following means.
[0012]
  (1) In a silver salt photothermographic dry imaging material having a photosensitive emulsion containing aliphatic silver carboxylate grains and photosensitive silver halide grains, a silver ion reducing agent, a binder and a crosslinking agent, and coated silver Amount 1.0-1.7 g / m²And 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and at least one of the silver ion reducing agents is represented by the general formula (S). A silver salt photothermographic dry imaging material characterized by the above.
[0013]
  (2) In a silver salt photothermographic dry imaging material having a photosensitive emulsion containing aliphatic silver carboxylate grains and photosensitive silver halide grains, a silver ion reducing agent, a binder and a crosslinking agent, and coated silver Amount 1.0-1.7 g / m²And 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and the thermal transition point of the photosensitive layer after development at a temperature of 100 to 180 ° C. A silver salt photothermographic dry imaging material, wherein the temperature is 46 to 200 ° C., and at least one of the silver ion reducing agents is represented by the general formula (S).
[0014]
  (3The compound represented by the general formula (S) is represented by the general formula (T).1Or2A silver salt photothermographic dry imaging material described in 1.
[0015]
  (4) The alkaline solution used in forming the aliphatic carboxylic acid silver salt particles is a mixture of sodium hydroxide and potassium hydroxide, and the ratio is 1:99 to 95: 5.3The silver salt photothermographic dry imaging material according to any one of the above.
[0016]
  (51) The aliphatic carboxylic acid silver salt particles are formed in the presence of a compound that functions as a crystal growth inhibitor or dispersant for the particles.4The silver salt photothermographic dry imaging material according to any one of the above.
[0017]
  (61) The glass transition temperature Tg of the binder is 70 to 105 ° C.5The silver salt photothermographic dry imaging material according to any one of the above.
[0018]
  (7) The above compound, wherein the compound functioning as a crystal growth inhibitor or dispersant is an alcohol having 10 or less carbon atoms.5A silver salt photothermographic dry imaging material described in 1.
[0019]
  (8) The above compound, wherein the compound functioning as a crystal growth inhibitor or dispersant is a branched aliphatic carboxylic acid or an aliphatic unsaturated carboxylic acid.5A silver salt photothermographic dry imaging material described in 1.
[0020]
  (9) The above compound, wherein the compound functioning as a crystal growth inhibitor or dispersant is gelatin or polyvinyl alcohol.5A silver salt photothermographic dry imaging material described in 1.
[0021]
  (10The above compound is characterized in that the compound functioning as a crystal growth inhibitor or dispersant is a polymer latex.5A silver salt photothermographic dry imaging material described in 1.
[0022]
  (111) The above 1 to 1 having a plurality of photosensitive layers0The silver salt photothermographic dry imaging material according to any one of the above.
[0023]
  (12) Hue angle after heat development h_ab180 ° <h_ab<1 to 1 above, characterized by being <270 °1The silver salt photothermographic dry imaging material according to any one of the above.
[0024]
  (13) 1-1 above2An image recording method, wherein the silver salt photothermographic dry imaging material according to any one of the above is exposed by a laser beam scanning exposure machine in which a scanning laser beam is a vertical multi-beam.
[0028]
  Silver salt photothermographic dry imaging material of the present inventionChargeThe amount of silver applied is 1.0 to 1.7 g / m²60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and at least one silver ion reducing agent used is represented by the general formula (S). It is characterized by that.
[0029]
  As an aspect of the silver salt photothermographic dry imaging material preferable in the present invention,A silver salt photothermographic dry imaging material having a photosensitive emulsion containing aliphatic silver carboxylate grains and photosensitive silver halide grains, a photosensitive layer containing a silver ion reducing agent, a binder and a cross-linking agent. Silver amount is 1.0-1.7 g / m ² And 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and the thermal transition point of the photosensitive layer after development at a temperature of 100 to 180 ° C. Silver salt photothermographic dry imaging material having a temperature of 46 to 200 ° C. and at least one of the silver ion reducing agents represented by the general formula (S)is there.
[0030]
Hereinafter, each component will be described.
(Aliphatic carboxylic acid silver salt)
The aliphatic carboxylic acid silver salt in the present invention is a reducible silver source, and a silver salt of an aliphatic carboxylic acid having 10 to 30, preferably 15 to 25 carbon atoms is preferable. Examples of suitable silver salts include the following.
[0031]
Silver salts such as gallic acid, succinic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Among these, preferable silver salts include silver behenate, silver arachidate, and silver stearate. In the present invention, it is preferable that two or more types of aliphatic carboxylic acid silver salts are mixed in order to improve developability and form a silver image having a high density and high contrast. For example, two or more types of aliphatic carboxylic acids are used. It is preferable to prepare the mixture by mixing a silver ion solution.
[0032]
The aliphatic carboxylic acid silver salt compound can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, and is described in Japanese Patent Application Laid-Open No. 9-127643. The controlled double jet method as described above is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then a controlled double jet. According to the method, the soap and silver nitrate are mixed to produce an aliphatic carboxylic acid silver salt crystal. At that time, silver halide grains may be mixed.
[0033]
The type of alkali metal salt used in the present invention is characterized by a mixture of sodium hydroxide and potassium hydroxide, and the ratio is preferably in the range of 1:99 to 95: 5, particularly 10: The range of 90 to 75:25 is preferred. When it reacts with an aliphatic carboxylic acid to form an alkali metal salt of an aliphatic carboxylic acid, the viscosity of the reaction solution can be controlled in a good state when used within the above range. In particular, when 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, it can be controlled to a better state.
[0034]
The aliphatic carboxylic acid silver salt in the present invention preferably has an average equivalent circle diameter of 0.05 to 0.8 μm and an average thickness of 0.005 to 0.07 μm, particularly preferably an average equivalent circle diameter. Is 0.2 to 0.5 μm and the average thickness is 0.01 to 0.05 μm. In short, the preferred aliphatic carboxylic acid silver salt in the present invention is flat.
[0035]
When the average equivalent circle diameter is less than 0.05 μm, the transparency is excellent, but the image storage stability is poor, and when the average particle diameter exceeds 0.8 μm, devitrification tends to be severe. When the average thickness is less than 0.005 μm, the surface area is large, and silver ions are rapidly supplied during development. In particular, at low density portions, silver ions that are not used for silver images and remain in the film are present in large quantities. Image storability is significantly deteriorated. When the average thickness exceeds 0.07 μm, the surface area is reduced and the image stability is improved, but the supply of silver during development is slow, resulting in unevenness of the developed silver shape particularly in the high density portion, resulting in the highest density. Tends to be low.
[0036]
To obtain the average equivalent circle diameter, the dispersed aliphatic carboxylic acid silver salt is diluted and dispersed on a grid with a carbon support film, and the transmission electron microscope (manufactured by JEOL Ltd., 2000FX type) is directly increased to 5000 times magnification. This is accomplished by taking a negative image as a digital image with a scanner, measuring 300 or more particle diameters (equivalent circle diameter) using appropriate image processing software, and calculating the average particle diameter.
[0037]
The average thickness is calculated by a method using a transmission electron microscope (hereinafter referred to as TEM) as shown below.
[0038]
First, the photosensitive layer coated on the support is attached to an appropriate holder with an adhesive, and an ultrathin slice having a thickness of 0.1 to 0.2 μm is produced using a diamond knife in a direction perpendicular to the support surface. . The prepared ultra-thin slice was supported on a copper mesh, transferred onto a carbon film hydrophilized by glow discharge, and cooled to −130 ° C. or less with liquid nitrogen, using a TEM, with a magnification of 5,000 to 40, A bright field image is observed at a magnification of 000 times, and the image is quickly recorded on a film, an imaging plate, a CCD camera, or the like. At this time, it is preferable to appropriately select a portion where the section is not torn or slack as the field of view to be observed.
[0039]
As the carbon film, it is preferable to use an ultrathin collodion, formbar, or the like supported by an organic film. More preferably, the carbon film is formed on a rock salt substrate and dissolved and removed. It is a carbon-only film obtained by solvent and ion etching. The acceleration voltage of TEM is preferably 80 to 400 kV, particularly preferably 80 to 200 kV.
[0040]
In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Japan Electron Microscopy Society Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Japan Electron Microscopy Society Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.
[0041]
A TEM image recorded on an appropriate medium is preferably decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing by a computer is performed. 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 the aliphatic carboxylate silver is extracted by binarization processing.
[0042]
300 or more of the extracted aliphatic carboxylic acid silver salt particles are manually measured with appropriate software to obtain an average value.
[0043]
The method for obtaining the aliphatic carboxylic acid silver salt 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 maintain, optimize the ratio of organic acid to soap, and the ratio of silver nitrate that reacts with soap.
[0044]
Preferred tabular aliphatic carboxylic acid silver salt particles in the present invention (aliphatic carboxylic acid silver salt 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) Is preferably preliminarily dispersed together with a binder, a surfactant or the like, if necessary, and then dispersed and ground with 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 rotating centrifugal radiation type stirrer (dissolver), or a high-speed rotating shear type stirrer (homomixer) can be used.
[0045]
As the media dispersing machine, a rolling mill such as a ball mill, a planetary ball mill or a vibrating ball mill, a bead mill which is a medium agitating mill, an attritor or other basket 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 collided at a high speed after dividing the liquid, and a type in which a thin orifice is passed.
[0046]
Examples of ceramics used for ceramic beads used when dispersing media include Al₂O_Three, BaTiO_Three, SrTiO_Three, MgO, ZrO, BeO, Cr₂O_Three, SiO₂, SiO₂-Al₂O_Three, Cr₂O_Three-MgO, MgO-CaO, MgO-C, MgO-Al₂O_Three(Spinel), SiC, TiO₂, K₂O, Na₂O, BaO, PbO, B₂O_Three, SrTiO_Three(Strontium titanate), BeAl₂O_Four, Y_ThreeAl_FiveO₁₂, ZrO₂-Y₂O_Three(Cubic Zirconia), 3BeO-Al₂O_Three-6SiO₂(Synthetic emerald), C (synthetic diamond), Si₂On-nH₂O, silicon nitride, yttrium stabilized zirconia, zirconia reinforced alumina and the like are preferable. Yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia are hereinafter abbreviated as zirconia) are particularly preferably used for the reason that less impurities are generated due to friction with beads and dispersers during dispersion.
[0047]
The apparatus used for dispersing the tabular aliphatic carboxylic acid silver salt particles preferable in the present invention includes zirconia, alumina, silicon nitride, boron nitride and the like as the material of the member in contact with the aliphatic carboxylic acid silver salt particles. Of these, it is preferable to use ceramics or diamond, and it is particularly preferable to use zirconia. When the above dispersion is performed, the binder concentration is preferably added in an amount of 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 through the main dispersion. As preferable operating conditions for the present dispersion, for example, when a high-pressure homogenizer is used as the dispersing means, preferable operating conditions are 29.42 to 98.06 MPa, and the number of operations is preferably 2 times or more. Moreover, when using a media disperser as a dispersion | distribution means, 6-13 m / sec of peripheral speed is mentioned as preferable conditions.
[0048]
In the present invention, the aliphatic carboxylic acid silver salt particles are preferably formed in the presence of a compound that functions as a crystal growth inhibitor or dispersant for the particles.
[0049]
In the present invention, the “compound functioning as a crystal growth inhibitor or dispersant” for the aliphatic carboxylic acid silver salt particles refers to a fatty acid compound under the conditions in which the compound is present in the production process of the aliphatic carboxylic acid silver salt particles. When a group carboxylic acid silver salt is produced, it refers to a compound having many functions and effects for reducing the particle size and / or monodispersing it when it is produced under non-coexisting conditions. Specific examples of the compound 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. Can be mentioned. A preferable addition amount is 10 to 200% by mass with respect to the aliphatic carboxylate silver. The alcohol having 10 or less carbon atoms is reduced in viscosity by increasing the solubility of sodium aliphatic carboxylate in the charging step, and monodispersed and reduced in particle size by increasing the stirring efficiency.
[0050]
On the other hand, branched aliphatic carboxylic acids containing isomers such as isoheptanoic acid, isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, isoarachidic acid, isobehenic acid and isohexaconic acid are also preferred. In this case, a preferable side chain includes an alkyl group or alkenyl group having 4 or less carbon atoms. In addition, aliphatic unsaturated carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, morotic acid, eicosenoic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, and ceracolonic acid It is done. Branched aliphatic carboxylic acids and aliphatic unsaturated carboxylic acids have higher steric hindrance than the main component linear aliphatic carboxylic acid silver when crystallization of the aliphatic carboxylic acid silver, and the disorder of the crystal lattice is large. Therefore, large crystals are not generated, and as a result, the particle size is reduced. These preferable addition amounts are 0.5 to 10 mol% of the aliphatic carboxylic acid silver.
[0051]
Other 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, sorbitan, sorbit and acetic acid Water-soluble organic solvents such as ethyl, methyl acetate, dimethylformamide, water-soluble organic solvents such as polyvinyl alcohol, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone, and gelatin Polymers are also mentioned as preferred compounds. A preferable addition amount is 0.1 to 20% by mass with respect to the aliphatic carboxylate silver.
[0052]
Polymer latex is also mentioned as a preferred compound. Examples of the polymer latex useful in the present invention include acrylate and / or methacrylate copolymers, polyester resins, acrylate-modified polyester resins, and polyurethane resins. Monomers used for the acrylate and / or methacrylate copolymer include alkyl acrylate, alkyl methacrylate, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, phenyl acrylate, phenylalkyl acrylate, cycloalkyl acrylate, cycloalkyl methacrylate, and other monomers. Examples thereof include styrene, vinyl chloride, vinylidene chloride, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, butadiene, and isoprene. These monomers form a latex by emulsion polymerization. Polyester resins include terephthalic acid, phthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanediacetic acid, adipic acid, sulfophthalic acid, etc. as dicarboxylic acid components, and ethylene glycol, propylene glycol, butylene as diol components. Glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, 1,4-cyclohexanedimethanol and the like can be mentioned, and these dicarboxylic acid components and diol components can be polycondensed through transesterification by a conventional method to obtain a polyester resin. I can do it.
[0053]
The acrylic modified polyester resin can be obtained by polymerizing the water-soluble or water-dispersible polyester resin in a water medium with a monomer used for the acrylate and / or methacrylate copolymer using a polymerization initiator.
[0054]
The polymer latex is present at the time of forming the organic silver, thereby physically inhibiting the crystal growth and reducing the particle size.
(binder)
Binders suitable for the silver salt photothermographic dry imaging material of the present invention are transparent or translucent and generally colorless and are natural polymer synthetic resins, polymers and copolymers, and other media forming films such as: gelatin, gum arabic, Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters) ) , Poly (urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. It may be hydrophilic or non-hydrophilic.
[0055]
Binders preferably used in the photosensitive layer of the silver salt photothermographic dry imaging material of the present invention are polyvinyl acetals, particularly preferably polyvinyl butyral. Details will be described later. For non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers with higher softening temperatures, especially polymers such as triacetyl cellulose and cellulose acetate butyrate preferable. If necessary, the above binders can be used in combination of two or more.
[0056]
Such a binder is used in an effective range to function as a binder. The effective range can be easily determined by one skilled in the art. For example, as an index for holding at least an aliphatic carboxylic acid silver salt in the photosensitive layer, the ratio of the binder to the aliphatic carboxylic acid silver salt is 15: 1 to 1: 2, particularly 8: 1 to 1: 1. A range is preferred. That is, the binder amount of the photosensitive layer is 1.5 to 6 g / m.²It is preferable that More preferably 1.7 to 5 g / m²It is. 1.5g / m²If it is less than 1, the density of the unexposed area will be significantly increased, and it may be unusable.
[0057]
In the present invention, another characteristic is that the thermal transition temperature of the photosensitive layer after development processing at a temperature of 100 to 180 ° C. is 46 to 200 ° C.
[0058]
The “thermal transition point temperature” in the present invention is a value indicated by the VICAT softening point or the ring and ball method, and is a differential scanning calorimeter (DSC) such as EXSTAR 6000 (manufactured by Seiko Electronics Co., Ltd.), DSC220C (Seiko Electronics Industry Co., Ltd.). Manufactured product), DSC-7 (manufactured by Perkin Elmer Co., Ltd.) and the like, and refers to an endothermic peak when a thermally developed photosensitive layer is isolated and measured. In general, a polymer compound has a glass transition point (Tg), but in silver salt photothermographic dry imaging materials, a large endothermic peak is present at a position lower than the Tg value of the binder resin used in the photosensitive layer. Appears. Paying attention to this thermal transition point temperature and setting this thermal transition point temperature to 46-200 ° C, not only the fastness of the formed coating film is increased, but also photographic performance such as sensitivity, maximum density, image storability, etc. It has been found to improve significantly.
[0059]
The glass transition temperature (Tg) is determined by the method described in “Polymer Handbook” from page III-139 to page III-179 (1966, Wiley and Sun, Inc.) by Brandrup et al. Tg in the case of a polymer resin is obtained by the following formula.
[0060]
Tg (copolymer) (° K) = v₁Tg₁+ V₂Tg₂+ ... + v_nTg_n
Where v₁, V₂... v_nRepresents the mass fraction of monomers in the copolymer, Tg₁, Tg₂... Tg_nRepresents Tg (° K) of a single polymer obtained from each monomer in the copolymer. The accuracy of Tg calculated according to the above equation is ± 5 ° C.
[0061]
In the silver salt photothermographic dry imaging material of the present invention, as the binder contained in the photosensitive layer containing aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, a reducing agent, etc. on the support, a conventionally known high Molecular compounds can be used. The Tg is 70 to 105 ° C., the number average molecular weight is 1,000 to 1,000,000, preferably 10,000 to 500,000, and the degree of polymerization is about 50 to 1,000. Examples of such include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic ester, 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 constituent unit, polyurethane resins, and various rubber resins.
[0062]
Moreover, phenol resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, epoxy-polyamide resin, polyester resin and the like can be mentioned. These resins are described in detail in “Plastic Handbook” issued by Asakura Shoten. These polymer compounds are not particularly limited and may be either a homopolymer or a copolymer as long as the glass transition temperature (Tg) of the derived polymer is in the range of 70 to 105 ° C.
[0063]
Polymers or copolymers containing such ethylenically unsaturated monomers as structural units include acrylic acid alkyl esters, acrylic acid aryl esters, methacrylic acid alkyl esters, methacrylic acid aryl esters, alkyl cyanoacrylates. Ester, cyanoacrylic acid aryl ester and the like, and the alkyl group and aryl group thereof may or may not be substituted. Specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl , Dimethyla Nophenoxyethyl, furfuryl, tetrahydrofurfuryl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2 -Acetoacetoxyethyl, 2-ethoxyethyl, 2-iso-propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) Examples thereof include ethyl, 2-diphenylphosphorylethyl, ω-methoxypolyethylene glycol (addition mole number n = 6), allyl, dimethylaminoethylmethyl chloride salt and the like.
[0064]
In addition, the following monomers can be used. Specific examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate. N-substituted acrylamides, N-substituted methacrylamides and acrylamides, methacrylamides: N-substituents include methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethyl Aminoethyl, phenyl, dimethyl, diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl), diacetone and the like; olefins: for example, dicyclopentadiene, ethylene, propylene, 1- Ten, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene, etc .; styrenes: for example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, tert-butylstyrene , Chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, etc .; vinyl ethers: for example, methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether N-substituted maleimides: As N-substituent, methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl , Benzyl, n-dodecyl, phenyl, 2-methylphenyl, 2,6-diethylphenyl, 2-chlorophenyl, etc .; others include 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-vinyl oxazolidone, N -Vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalonnitrile, vinylidene chloride and the like can be mentioned.
[0065]
Among these, particularly preferred examples include methacrylic acid alkyl esters, methacrylic acid aryl esters, and styrenes. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. The polymer compound having an acetal group is preferable because it is excellent in compatibility with the aliphatic carboxylic acid to be produced and has a great effect of preventing the film from being softened.
[0066]
As the polymer compound having an acetal group, a compound represented by the following general formula (V) is particularly preferable.
[0067]
[Chemical Formula 3]

[0068]
Where R₁Represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, preferably a group other than an aryl group. R₂Is an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, -COR_ThreeOr -CONHR_ThreeRepresents. R_ThreeIs R₁It is synonymous with.
[0069]
R₁, R₂, R_ThreeAs an unsubstituted alkyl group represented by this, a C1-C20 thing is preferable, Most preferably, it is C1-C6. These may be linear or branched, and preferably a linear alkyl group. Examples of such unsubstituted alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, t-amyl, n -Hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-octadecyl group, etc. Is particularly preferably a methyl group or a propyl group.
[0070]
As an unsubstituted aryl group, a C6-C20 thing is preferable, for example, a phenyl group, a naphthyl group, etc. are mentioned. Examples of the group that can be substituted with the above alkyl group or aryl group include an alkyl group (for example, a methyl group, an n-propyl group, a t-amyl group, a t-octyl group, an n-nonyl group, a dodecyl group), an aryl group. (For example, phenyl group), nitro group, hydroxyl group, cyano group, sulfo group, alkoxy group (for example, methoxy group), aryloxy group (for example, phenoxy group), acyloxy group (for example, acetoxy group), Acylamino group (for example, acetylamino group), sulfonamide group (for example, methanesulfonamide group), sulfamoyl group (for example, methylsulfamoyl group), halogen atom (for example, fluorine atom, chlorine atom, bromine atom) ), Carboxy group, carbamoyl group (for example, methylcarbamoyl group, etc.), alkoxycarbonyl group (for example, metho Shiruboniru group), a sulfonyl group (e.g., methyl sulfonyl group). When there are two or more substituents, they may be the same or different. The total carbon number of the substituted alkyl group is preferably 1-20, and the total carbon number of the substituted aryl group is preferably 6-20.
[0071]
R₂As -COR_Three(R_ThreeIs an alkyl group or an aryl group), -CONHR_Three(R_ThreeIs preferably an aryl group. a, b, and c are values indicating the mass of each repeating unit in mol (mol)%, a is 40 to 86 mol%, b is 0 to 30 mol%, and c is in the range of 0 to 60 mol% A + b + c = 100 mol%, particularly preferably a is in the range of 50 to 86 mol%, b is 5 to 25 mol%, and c is 0 to 40 mol%. Each repeating unit having each composition ratio of a, b, and c may be composed of only the same one or may be composed of different ones.
[0072]
As the polyurethane resin that can be used in the present invention, known resins such as polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, polyester polycarbonate polyurethane, and polycaprolactone polyurethane can be used. For all of the polyurethanes shown here, if necessary, -COOM, -SO_ThreeM, -OSO_ThreeM, -P = O (OM)₂, -OP = O (OM)₂(M represents a hydrogen atom or an alkali metal base), -NR₂, -N⁺R₂(R₂Represents a hydrocarbon group), and those obtained by introducing at least one polar group selected from an epoxy group, —SH, —CN and the like by copolymerization or addition reaction are preferably used. The amount of such polar groups is 10^-1-10^-8Mol / g, preferably 10^-2-10^-6Mol / g. In addition to these polar groups, it is preferable to have at least one OH group in total at least one at the polyurethane molecule end. Since OH groups are cross-linked with polyisocyanate which is a curing agent to form a three-dimensional network structure, it is more preferable that the OH groups are contained in the molecule. In particular, it is preferable that the OH group is at the molecular end because the reactivity with the curing agent is high. The polyurethane preferably has 3 or more OH groups at the molecular terminals, and particularly preferably 4 or more. When polyurethane is used, the glass transition temperature is 70 to 105 ° C., the breaking elongation is 100 to 2000%, and the breaking stress is 0.5 to 100 N / mm.²Is preferred.
[0073]
The polymer compound represented by the general formula (V) of the present invention can be synthesized by a general synthesis method described in “Vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Publishing Society, 1962). it can. Examples of typical synthesis methods are given below, but the present invention is not limited to these typical synthesis examples.
[0074]
Synthesis Example 1: Synthesis of P-1
20 g of polyvinyl alcohol (GOHSENOL GH18) manufactured by Nippon Gosei Co., Ltd. and 180 g of pure water were charged and dispersed in pure water so that the polyvinyl alcohol became a 10% by mass solution. Then, the mixture was cooled to 75 ° C. to prepare an aqueous polyvinyl alcohol solution. Further, 1.6 g of 10% by mass of hydrochloric acid as an acid catalyst was added to the aqueous polyvinyl alcohol solution, and this was designated as Drop A. Subsequently, 11.5 g of a mixture of butyraldehyde and acetaldehyde in a molar ratio of 1: 1 was weighed, and this was designated as Droplet B. 100 ml of pure water was placed in a 1000 ml four-necked flask equipped with a condenser and a stirrer, heated to 85 ° C. and vigorously stirred. To this, a dropping funnel in which the dropping liquid A and the dropping liquid B were kept at 75 ° C. was added dropwise simultaneously with stirring for 2 hours. At this time, the reaction was carried out while paying attention to the stirring speed and preventing fusion of the precipitated particles. After the completion of dropping, 7 g of 10% by mass hydrochloric acid was added as an acid catalyst, and the mixture was stirred at a temperature of 85 ° C. for 2 hours to sufficiently react. Then, it cooled to 40 degreeC, neutralized using sodium hydrogencarbonate, and after repeating water washing 5 times, it separated by filtration, the polymer was taken out and dried, and P-1 was obtained. When Tg of the obtained P-1 was measured using DSC, Tg was 75 ° C.
[0075]
Other polymer compounds listed in Table 1 were synthesized in the same manner. These polymer compounds (polymers) may be used alone or in a blend of two or more.
[0076]
It is preferable to use the polymer as a main binder in the photosensitive layer. The main binder here refers to a state where the polymer occupies 50% by mass or more of the total binder of the photosensitive layer. Therefore, other polymers may be blended and used within a range of less than 50% by weight of the total binder. These polymers are not particularly limited as long as the polymers are soluble in the solvent. More preferably, polyvinyl acetate, a polyacrylic resin, a urethane resin, etc. are mentioned.
[0077]
The constitution of the polymer compound according to the present invention is shown below. In the table, Tg is a value measured by a differential scanning calorimeter (DSC) manufactured by Seiko Electronics Industry.
[0078]
[Table 1]

[0079]
In addition, P-9 in Table 1 is B-79 (made by Solusia).
(Crosslinking agent)
Although it is known that the use of a crosslinking agent for the above binder improves film formation and reduces development unevenness, in the present invention, suppression of fogging during storage and generation of printed-out silver after development are suppressed. There is also an effect.
[0080]
As the cross-linking agent used in the present invention, various cross-linking agents conventionally used for silver halide photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, and ethyleneimine-based as described in JP-A No. 50-96216 are used. , Vinylsulfone-based, sulfonic acid ester-based, acryloyl-based, carbodiimide-based, and silane compound-based crosslinking agents may be used, but the following isocyanate-based compounds, silane compounds, epoxy compounds, or acid anhydrides are preferable.
[0081]
An isocyanate-based and thioisocyanate-based crosslinking agent represented by the following general formula [1], which is one of the preferred ones, will be described.
[0082]
General formula [1]
X = C = N−L− (N = C = X)_v
In the formula, v is 1 or 2, L is a divalent linking group which can be an alkylene, alkenylene, arylene group or alkylarylene group, and X is an oxygen or sulfur atom.
[0083]
In the compound represented by the general formula [1], the aryl ring of the arylene group may have a substituent. Examples of preferred substituents are selected from halogen atoms (for example, bromine atom or chlorine atom), hydroxyl groups, amino groups, carboxyl groups, alkyl groups and alkoxy groups.
[0084]
The isocyanate-based crosslinking agent includes isocyanates having at least two isocyanate groups and adducts thereof (adducts), and more specifically, aliphatic diisocyanates and aliphatic diisocyanates having a cyclic group. Benzene diisocyanates, naphthalene diisocyanates, biphenyl isocyanates, diphenylmethane diisocyanates, triphenylmethane diisocyanates, triisocyanates, tetraisocyanates, adducts of these isocyanates and divalent or trivalent with these isocyanates Examples include adducts with polyalcohols.
[0085]
As specific examples, isocyanate compounds described on pages 10 to 12 of JP-A-56-5535 can be used.
[0086]
The adduct body of isocyanate and polyalcohol has particularly high ability to improve interlayer adhesion, and prevent layer peeling, image shift and bubble generation. Such isocyanates may be placed in any part of the photothermographic material. For example, in the support (especially when the support is paper, it can be included in the size composition) photosensitive layer, surface protective layer, intermediate layer, antihalation layer, subbing layer, etc. It can be added to any layer and can be added to one or more of these layers.
[0087]
As the thioisocyanate-based crosslinking agent that can be used in the present invention, compounds having a thioisocyanate structure corresponding to the above-mentioned isocyanates are also useful.
[0088]
The addition amount of the crosslinking agent used in the present invention is in the range of 0.001 to 2 mol, preferably 0.005 to 0.5 mol, with respect to 1 mol of silver.
[0089]
The isocyanate compound and the thioisocyanate compound are preferably compounds that function as the above-mentioned crosslinking agent. However, in the above general formula, v is zero (0), that is, a compound having only one functional group. Good results are obtained.
[0090]
Examples of the silane compound that can be used as a crosslinking agent in the present invention include compounds represented by general formula (1) or general formula (2) disclosed in Japanese Patent Application No. 2000-077904.
[0091]
In these general formulas, R¹~ R⁸Are each a linear, branched, or cyclic alkyl group having 1 to 30 carbon atoms (methyl group, ethyl group, butyl group, octyl group, dodecyl group, cycloalkyl group, etc.), alkenyl group (propenyl group). , Butenyl group, nonenyl group, etc.), alkynyl group (acetylene group, bisacetylene group, phenylacetylene group, etc.), aryl group or heterocyclic group (phenyl group, naphthyl group, tetrahydropyran group, pyridyl group, furyl group, thiophenyl group) , An imidazole group, a thiazole group, a thiadiazole group, an oxadiazole group, etc.), and the substituent can have either an electron-withdrawing substituent or an electron-donating substituent.
[0092]
R¹~ R⁸It is preferable that at least one of the substituents selected from is a non-diffusible group or an adsorptive group, particularly R²Is preferably a non-diffusible group or an adsorptive group.
[0093]
The non-diffusible group is also called a ballast group and is preferably an aliphatic group having 6 or more carbon atoms or an aryl group into which an alkyl group having 3 or more carbon atoms is introduced. Diffusion resistance varies depending on the amount of binder and cross-linking agent used, but by introducing a diffusion-resistant group, the intramolecular movement distance at room temperature is suppressed, and the reaction over time can be suppressed.
[0094]
The epoxy compound that can be used as the crosslinking agent is not particularly limited as long as it has one or more epoxy groups and the number of epoxy groups, molecular weight, and the like. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. Moreover, any of a monomer, an oligomer, a polymer, etc. may be sufficient as an epoxy compound, and the number of the epoxy groups which exist in a molecule | numerator is about 1-10 normally, Preferably it is 2-4. When the epoxy compound is a polymer, it may be a homopolymer or a copolymer, and the particularly preferred range of the number average molecular weight Mn is about 2000 to 20000.
[0095]
As the epoxy compound, a compound represented by the following general formula [2] is preferable.
[0096]
[Formula 4]

[0097]
In the general formula [2], the substituent of the alkylene group represented by R is preferably a group selected from a halogen atom, a hydroxyl group, a hydroxyalkyl group or an amino group. The linking group represented by R preferably has an amide linking moiety, an ether linking moiety, or a thioether linking moiety. The divalent linking group represented by X is —SO₂-, -SO₂NH-, -S-, -O-, or -NR'- is preferred. Here, R ′ is a monovalent group, preferably an electron withdrawing group.
[0098]
These epoxy compounds may be used alone or in combination of two or more. The amount added is not particularly limited, but 1 × 10^-6~ 1x10^-2Mol / m²Is preferred, more preferably 1 × 10^-Five~ 1x10^-3Mol / m²Range.
[0099]
The epoxy compound can be added to any layer on the photosensitive layer side of the support such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer, and one or more of these layers can be added. Can be added. Further, it can be added to any layer on the opposite side of the support from the photosensitive layer. In addition, any layer may be sufficient in the type of photosensitive material in which a photosensitive layer exists on both surfaces.
[0100]
An acid anhydride is a compound having at least one acid anhydride group represented by the following structural formula.
[0101]
-CO-O-CO-
The acid anhydride is not particularly limited as long as it has at least one such acid anhydride group, and the number, molecular weight, and the like of the acid anhydride group are not limited, but a compound represented by the general formula [A] is preferable.
[0102]
[Chemical formula 5]

[0103]
In the general formula [A], Z represents an atomic group necessary for forming a monocyclic or polycyclic system. These ring systems may be unsubstituted or substituted. Examples of substituents include alkyl groups (eg, methyl, ethyl, hexyl), alkoxy groups (eg, methoxy, ethoxy, octyloxy), aryl groups (eg, phenyl, naphthyl, tolyl), hydroxyl groups, aryloxy groups (For example, phenoxy), alkylthio group (for example, methylthio, butylthio), arylthio group (for example, phenylthio), acyl group (for example, acetyl, propionyl, butyryl), sulfonyl group (for example, methylsulfonyl, phenylsulfonyl), acylamino group Sulfonylamino group, acyloxy group (for example, acetoxy, benzoxy), carboxyl group, cyano group, sulfo group, and amino group. As the substituent, those not containing a halogen atom are preferable.
[0104]
These acid anhydrides may be used alone or in combination of two or more. The amount added is not particularly limited, but 1 × 10^-6~ 1x10^-2Mol / m²Is preferred, more preferably 1 × 10^-Five~ 1x10^-3Mol / m²Range.
[0105]
In the present invention, the acid anhydride can be added to any layer on the photosensitive layer side of the support, such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer. It can be added to two or more layers. Moreover, you may add to the same layer as the said epoxy compound.
(Reducing agent)
As a reducing agent used for this invention, the bisphenol derivative represented by the general formula (S) mentioned above is preferable, More preferably, it is a compound which has the cyclic structure represented by the general formula (T) mentioned above. The ring is preferably a 6-membered ring.
[0106]
In the general formula (S), Z represents a group of atoms necessary to form a 3- to 10-membered non-aromatic ring together with a carbon atom. Cyclobutyl, cyclobutenyl, oxetanyl, azetidinyl as the 4-membered ring, cyclopentyl, cyclopentenyl, cyclopentadienyl as the 5-membered ring, tetrahydrofuranyl, pyrrolidinyl, tetrahydrothienyl, cyclohexyl, cyclohexenyl, cyclohexadienyl as the 6-membered ring, Tetrahydropyranyl, pyranyl, piperidinyl, dioxanyl, tetrahydrothiopyranyl, norcaranyl, norpinanyl, norbornyl, 7-membered ring is cycloheptyl, cycloheptynyl, cycloheptadienyl, 8-membered ring is cyclooctanyl, citronyl Looctenyl, cyclooctadienyl, cyclooctatrienyl, 9-membered ring is cyclononanyl, cyclononenyl, cyclononadienyl, cyclononatrienyl, 10-membered ring is cyclodecanyl, cyclodecenyl, cyclodecadienyl, cyclodecatrienyl, etc. These groups are mentioned.
[0107]
Preferably it is a 3-6 membered ring, More preferably, it is a 5-6 membered ring, Most preferably, it is a 6 membered ring, Among these, the hydrocarbon ring which does not contain a hetero atom is preferable. The ring may form a spiro bond with another ring through a spiro atom, or may be condensed in any way with another ring including an aromatic ring. Moreover, it can have an arbitrary substituent on the ring. Specific examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, etc.), cycloalkyl group (for example, cyclohexyl group, cycloheptyl group, etc.), alkenyl group (for example, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl) -3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, etc.), cycloalkenyl group (eg 1-cycloalkenyl group, 2-cycloalkenyl group etc.), alkynyl group (eg ethynyl group, 1-propynyl group etc.), alkoxy group (eg methoxy group, ethoxy group, propoxy group etc.), alkylcarbonyloxy group For example, acetyloxy group etc.), alkylthio group (eg methylthio group, trifluoromethylthio group etc.), carboxyl group, alkylcarbonylamino group (eg acetylamino group etc.), ureido group (eg methylaminocarbonylamino group etc.) ), Alkylsulfonylamino groups (for example, methanesulfonylamino group, etc.), alkylsulfonyl groups (for example, methanesulfonyl group, trifluoromethanesulfonyl group, etc.), carbamoyl groups (for example, carbamoyl group, N, N-dimethylcarbamoyl group, N -Morpholinocarbonyl group, etc.), sulfamoyl group (sulfamoyl group, N, N-dimethylsulfamoyl group, morpholinosulfamoyl group, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkylsulfone Group (for example, methanesulfonamide group, butanesulfonamide group, etc.), alkylamino group (for example, amino group, N, N-dimethylamino group, N, N-diethylamino group, etc.), sulfo group, phosphono group, sulfite Group, sulfino group, alkylsulfonylaminocarbonyl group (eg, methanesulfonylaminocarbonyl group, ethanesulfonylaminocarbonyl group, etc.), alkylcarbonylaminosulfonyl group (eg, acetamidosulfonyl group, methoxyacetamidosulfonyl group, etc.), alkynylaminocarbonyl group (For example, acetamidocarbonyl group, methoxyacetamidocarbonyl group, etc.), alkylsulfinylaminocarbonyl group (for example, methanesulfinylaminocarbonyl group, ethanesulfinylaminocarbonyl group) Etc.). Moreover, when there are two or more substituents, they may be the same or different. A particularly preferred substituent is an alkyl group. R₀', R₀"Represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, t-butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, cyclohexyl group, cycloheptyl group, 1-methylcyclohexyl group, ethenyl- 2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 1-cycloalkenyl group, 2-cycloalkenyl group, ethynyl group, 1- And propynyl group, etc. More preferably, methyl group, ethyl group, isopropyl group, t-butyl group, cyclohexyl group, 1-methyl And a cyclohexyl group, preferably a methyl group, a t-butyl group, and a 1-methylcyclohexyl group, and most preferably a methyl group. Specific examples of the heterocyclic group include aromatic heterocycles such as a pyridine group, a quinoline group, an isoquinoline group, an imidazole group, a pyrazole group, a triazole group, an oxazole group, a thiazole group, an oxadiazole group, a thiadiazole group, and a tetrazole group. Non-aromatic heterocyclic groups such as a cyclic group, piperidino group, morpholino group, tetrahydrofuryl group, tetrahydrothienyl group, tetrahydropyranyl group, etc. These groups may further have a substituent. Examples of the group include substituents on the above-described ring.₀', R₀″ May be the same or different, but most preferably all are methyl groups.
[0108]
R_xRepresents a hydrogen atom or an alkyl group, and the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, cyclohexyl group, cycloheptyl. Group, 1-methylcyclohexyl group, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 1-cycloalkenyl group, 2 -A cycloalkenyl group, an ethynyl group, a 1-propynyl group, etc. are mentioned. More preferably, they are a methyl group, an ethyl group, an isopropyl group, and a hydrogen atom.
[0109]
Q₀Represents a substitutable group on the benzene ring, specifically, an alkyl group having 1 to 25 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group). Group), halogenated alkyl group (trifluoromethyl group, perfluorooctyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group etc.), alkynyl group (propargyl group etc.), glycidyl group, acrylate group, methacrylate group, Aryl group (phenyl group, etc.), heterocyclic group (pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group , Tetrazolyl groups, etc.), halogen atoms (chlorine Element, bromine atom, iodine atom, fluorine atom, etc.), alkoxy group (methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group) Etc.), alkoxycarbonyl group (methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group etc.), aryloxycarbonyl group (phenyloxycarbonyl group etc.), sulfonamide group (methanesulfonamide group, ethanesulfonamide group, Butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl group (aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butyl) Minosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylamino) Carbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), amide group (a Cetamide group, propionamide group, butanamide group, hexaneamide group, benzamide group, etc.), sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), Amino group (amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group, etc. Can be mentioned. These groups may be further substituted with these groups. n and m represent an integer of 0 to 2, and most preferably n and m are 0.
[0110]
In general formula (T), Q₁Represents a halogen atom, an alkyl group, an aryl group, or a heterocyclic group;₂Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, or a heterocyclic group. Specific examples of the halogen atom include chlorine, bromine, fluorine, and iodine. Preferred are fluorine, chlorine and bromine. Specifically, the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, cyclohexyl group, cycloheptyl. Group, 1-methylcyclohexyl group, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 1-cycloalkenyl group, 2 -A cycloalkenyl group, an ethynyl group, a 1-propynyl group, etc. are mentioned. More preferably, they are a methyl group and an ethyl group. Specific examples of the aryl group include a phenol group and a naphthyl group. Preferred examples of the heterocyclic group include 5- to 6-membered heteroaromatic groups such as a pyridyl group, a furyl group, a thienyl group, and an oxazolyl group. G represents a nitrogen atom or a carbon atom, preferably a carbon atom. ng represents 0 or 1, but is preferably 1. Q₁Most preferably, it is a methyl group. Q₂Is preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.
[0111]
Z₂Represents an atomic group necessary for constituting a 3 to 10-membered non-aromatic ring together with a carbon atom and G, and the 3 to 10-membered non-aromatic ring has the same meaning as in the general formula (S). It is.
[0112]
R₀', R₀″ 、 R_x, Q₀, N, and m have the same meaning as in general formula (S).
[0113]
Moreover, as a reducing agent used for this invention, it is preferable to employ | adopt the compound by which at least 1 type is represented with the following general formula (B).
[0114]
[Chemical 6]

[0115]
In the formula, X represents a chalcogen atom or CHR, and R represents a hydrogen atom, a halogen atom, or a chain aliphatic group having 7 or less carbon atoms. R ′ and R ″ each represents an alkyl group.
[0116]
In the general formula (B), the chalcogen atom represented by X is specifically a sulfur atom, a selenium atom or a tellurium atom, preferably a sulfur atom. R represents a hydrogen atom, a halogen atom, or a chain aliphatic group having 7 or less carbon atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom, and a chain shape having 7 or less carbon atoms. Examples of the aliphatic group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, hexyl group, heptyl group, vinyl group, allyl group, butenyl group, hexadienyl group, ethenyl-2-propenyl group, 3- A butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group and the like can be mentioned. R is preferably a chain aliphatic group having 7 or less carbon atoms, more preferably a methyl group, an ethyl group, or an isopropyl group.
[0117]
These groups may further have a substituent. Examples of the substituent include a halogen atom (for example, fluorine atom, chlorine atom, bromine atom), cycloalkyl group (for example, cyclohexyl group, cycloheptyl group, etc.). A cycloalkenyl group (eg, 1-cycloalkenyl group, 2-cycloalkenyl group, etc.), an alkoxy group (eg, methoxy group, ethoxy group, propoxy group, etc.), an alkylcarbonyloxy group (eg, acetyloxy group, etc.), An alkylthio group (eg, methylthio group, trifluoromethylthio group, etc.), carboxyl group, alkylcarbonylamino group (eg, acetylamino group, etc.), ureido group (eg, methylaminocarbonylamino group, etc.), alkylsulfonylamino group (eg, , Methanesulfonylamino group, etc.), alkylsulfonyl (For example, methanesulfonyl group, trifluoromethanesulfonyl group, etc.), carbamoyl group (for example, carbamoyl group, N, N-dimethylcarbamoyl group, N-morpholinocarbonyl group, etc.), sulfamoyl group (sulfamoyl group, N, N-dimethylsulfur group, etc.) Famoyl group, morpholinosulfamoyl group, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group (for example, methanesulfonamide group, butanesulfonamide group, etc.), alkylamino group (for example, Amino group, N, N-dimethylamino group, N, N-diethylamino group, etc.), sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonylaminocarbonyl group (for example, methanesulfonylaminocarbonyl group, ethanesulfonylamino group) Carbonyl group etc.), alkylcarbonylaminosulfonyl group (eg acetamidosulfonyl group, methoxyacetamidosulfonyl group etc.), alkynylaminocarbonyl group (eg acetamidocarbonyl group, methoxyacetamidocarbonyl group etc.), alkylsulfinylaminocarbonyl group (eg Methanesulfinylaminocarbonyl group, ethanesulfinylaminocarbonyl group and the like). Moreover, when there are two or more substituents, they may be the same or different.
[0118]
R ′ and R ″ each represents an alkyl group, and specifically, preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, t -Butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, cyclohexyl group, cycloheptyl group, 1-methylcyclohexyl group, ethenyl-2-propenyl group, 3-butenyl group, Examples include 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 1-cycloalkenyl group, 2-cycloalkenyl group, ethynyl group, 1-propynyl group, etc. A methyl group, an ethyl group, an isopropyl group, a t-butyl group, a cyclohexyl group, and a 1-methylcyclohexyl group, more preferably methyl. , T-butyl group, 1-methylcyclohexyl group, most preferably a methyl group, which may further have a substituent, and the substituent may be a substituent on the aforementioned ring. A plurality of R ′ and R ″ may be the same or different, but most preferably all are methyl groups.
[0119]
Specific examples of the compounds represented by the general formulas (S), (T), and (B) are listed below, but the present invention is not limited thereto.
[0120]
[Chemical 7]

[0121]
[Chemical 8]

[0122]
[Chemical 9]

[0123]
Embedded image

[0124]
Embedded image

[0125]
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[0126]
Embedded image

[0127]
Embedded image

[0128]
Embedded image

[0129]
Embedded image

[0130]
The compounds represented by the general formulas (S), (T), and (B) can be easily synthesized by a conventionally known method. A preferred synthesis scheme is illustrated below by taking the general formula (S) as an example.
[0131]
Embedded image

[0132]
That is, preferably 2 equivalents of phenol and 1 equivalent of aldehyde are dissolved or suspended in the absence of a solvent or in a suitable organic solvent, and a catalytic amount of acid is added, preferably at a temperature of -20 ° C to 120 ° C. By reacting for 0.5 to 60 hours, the desired compound represented by the general formula (S) can be obtained in good yield. The same applies to the compound represented by formula (T) or (B).
[0133]
The organic solvent is preferably a hydrocarbon organic solvent, and specific examples include benzene, toluene, xylene, dichloromethane, chloroform and the like. Preferably it is toluene. Furthermore, it is most preferable to make it react without a solvent from the point of a yield. Although any inorganic acid and organic acid can be used as the acid catalyst, concentrated hydrochloric acid, p-toluenesulfonic acid, and phosphoric acid are preferably used. The catalyst amount is preferably 0.001 to 1.5 equivalents relative to the corresponding aldehyde. The reaction temperature is preferably around room temperature (15 to 25 ° C.), and the reaction time is preferably 3 to 20 hours.
[0134]
In the present invention, U.S. Pat. Nos. 3,589,903, 4,021,249 or British Patent 1,486,148 and JP-A-51-51933, 50-36110, 50- Polyphenol compounds described in 116023, 52-84727 or JP-B 51-35727, for example, 2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-2,2 ' Bisnaphthols described in US Pat. No. 3,672,904 such as dihydroxy-1,1′-binaphthyl, and the like, and further, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6- U.S. Pat. Nos. 3,801,32 such as dichloro-4-benzenesulfonamidophenol and 4-benzenesulfonamidonaphthol Sulfonamidophenols or sulfonamidonaphthols, such as described in JP-can also be used as the silver ion reducing agent.
[0135]
The amount of reducing agent used, including the compounds represented by the general formulas (S), (T), and (B), is preferably 1 × 10 6 per mole of silver.^-2-10 mol, especially 1 x 10^-2~ 1.5 mol.
[0136]
The amount of the reducing agent used in the photothermographic dry imaging material of the present invention varies depending on the type of aliphatic carboxylic acid silver salt (organic silver salt), the type of reducing agent, and other additives. A suitable amount is 0.05 to 10 mol, preferably 0.1 to 3 mol, per mol of salt. In addition, within the range of this amount, two or more of the reducing agents described above may be used in combination. In the present invention, it may be preferable that the reducing agent is added to and mixed with a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt grains and a solvent immediately before coating, because photographic performance fluctuation due to stagnation time is small. is there.
[0137]
In the present invention, the amount of coated silver is preferably selected in accordance with the purpose of the silver salt photothermographic imaging material, but 0.6 to 2.5 g / m for medical images.²Is preferable, and 1.0-1.7 g / m is further preferable.²Is preferred. Of the amount of coated silver, the amount derived from silver halide preferably accounts for 2 to 18%, more preferably 3 to 15%, based on the total silver amount.
[0138]
In the present invention, the coating density of silver halide grains having a diameter of 0.01 μm or more (equivalent particle diameter equivalent to sphere) is 1 × 10¹⁴~ 1x10¹⁸Pieces / m²Is preferred, and further 1 × 10¹⁵~ 1x10¹⁷Pieces / m²Is preferred.
(Photosensitive silver halide)
The photosensitive silver halide grains (also simply referred to as silver halide grains) in the present invention will be described. Incidentally, the photosensitive silver halide grains in the present invention can inherently absorb light as an intrinsic property of silver halide crystals, or artificially generate visible light or infrared light by a physicochemical method. Physicochemical changes in the silver halide crystal and / or on the crystal surface when absorbing light in any region within the light wavelength range from the ultraviolet light region to the infrared light region. Refers to silver halide crystal grains that have been processed and produced so that can occur.
[0139]
The silver halide grains themselves used in the present invention are P.I. Chifie et Physique Photographic (published by PaulMontel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared as a silver halide grain emulsion using the method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al. That is, any method such as an acidic method, a neutral method, and an ammonia method may be used, and the formation of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, and a combination thereof. Of these methods, the so-called controlled double jet method, in which silver halide grains are prepared while controlling the formation conditions, is preferred. 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.
[0140]
Grain formation is usually divided into two stages: silver halide seed grain (nucleus) generation and grain growth, and these may be performed continuously at one time. Alternatively, the nucleus (seed grain) formation and grain growth may be separated. The method of performing may be used. The controlled double jet method, in which particles are formed by controlling pAg, pH, etc., which are particle forming conditions, is preferable because the particle shape and size can be controlled. For example, when performing a method in which nucleation and grain growth are separated, first, soluble silver salt and soluble halogen salt are uniformly and rapidly mixed in an aqueous gelatin solution to produce nuclei (seed grains) (nucleation process). Thereafter, silver halide grains are prepared by a grain growth process in which grains are grown while supplying a soluble silver salt and a soluble halogen salt under controlled pAg, pH and the like. After the formation of the grains, the desired salt halide emulsion can be obtained by removing unnecessary salts by a desalting step by a known desalting method such as a noodle method, a flocculation method, an ultrafiltration method, or an electrodialysis method. I can do it.
[0141]
The silver halide grains preferably have a smaller average particle diameter in order to keep the white turbidity and color tone (yellowishness) after image formation low and to obtain good image quality, and the average particle diameter is less than 0.02 μm. The value when excluded from measurement is preferably 0.035 μm or more and 0.055 μm or less. The grain size here means the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. Further, when the silver halide grains are tabular grains, it means the diameter when converted into a circular image having the same area as the projected area of the main surface.
[0142]
In the present invention, the silver halide grains are preferably monodispersed. The term “monodispersed” as used herein means that the coefficient of variation of the particle diameter obtained by the following formula is 30% or less. Preferably it is 20% or less, More preferably, it is 15% or less.
[0143]
Variation coefficient of particle size% = standard deviation of particle size / average value of particle size × 100
Examples of the shape of the silver halide grains include cubes, octahedrons, tetradecahedral grains, tabular grains, spherical grains, rod-like grains, and potato-like grains. Among these, cubic, octahedral, and tetrahedral Tabular silver halide grains are preferred.
[0144]
The average aspect ratio when using tabular silver halide grains is preferably 1.5 to 100, more preferably 2 to 50. These are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958 and the like, and the desired tabular grains can be easily obtained. Further, grains having rounded corners of silver halide grains can be preferably used.
[0145]
There is no particular limitation on the crystal habit on the outer surface of the silver halide grain, but when using a spectral sensitizing dye having crystal habit (plane) selectivity in the adsorption reaction of the silver sensitizing dye on the surface of the silver halide grain It is preferable to use silver halide grains having a relatively high proportion of crystal habits adapted to the selectivity. For example, when using a sensitizing dye that is selectively adsorbed on the crystal face of the Miller index [100], the proportion of the [100] face on the outer surface of the silver halide grain is preferably high, and this ratio is 50 % Or more, more preferably 70% or more, and particularly preferably 80% or more. The ratio of the Miller index [100] plane is a T.K. based on the adsorption dependency of the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging Sci. 29, 165 (1985).
[0146]
The silver halide grains used in the present invention are preferably prepared using low molecular weight gelatin having an average molecular weight of 50,000 or less at the time of forming the grains, 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 2000 to 40000, more preferably 5000 to 25000. The average molecular weight of gelatin can be measured by gel filtration chromatography. Low molecular weight gelatin can be decomposed by adding gelatin-degrading enzyme to a commonly used gelatin aqueous solution with an average molecular weight of about 100,000, hydrolyzing by adding acid or alkali, and heating under atmospheric pressure or pressure. Can be obtained by thermal decomposition, decomposition by ultrasonic irradiation, or a combination of these methods.
[0147]
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 at a low concentration of 0.05 to 3.0% by mass.
[0148]
For the silver halide grains used in the present invention, it is preferable to use a compound represented by the following general formula when the grains are formed.
[0149]
General formula
YO (CH₂CH₂O)_m(CH (CH_Three) CH₂O)_p(CH₂CH₂O)_nY
In the formula, Y is a hydrogen atom, -SO._ThreeM 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. Represents a chain or cyclic group. m and n each represents 0 to 50, and p represents 1 to 100.
[0150]
The polyethylene oxide compound represented by the above general formula comprises a step of producing a gelatin aqueous solution, a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution, and an emulsion. It has been preferably used as an antifoaming agent for significant foaming when the emulsion raw material is stirred or moved, such as a step of coating on a support. 44-9497. The polyethylene oxide compound represented by the above general formula also functions as an antifoaming agent during nucleation.
[0151]
The polyethylene oxide compound represented by the above general formula is preferably used at 1% by mass or less, more preferably 0.01 to 0.1% by mass with respect to silver.
[0152]
The polyethylene oxide compound represented by the above general formula may 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 or You may add and use for the silver salt aqueous solution and halide aqueous solution which are used at the time of formation. Preferably, it is used by adding 0.01 to 2.0% by mass to the aqueous halide solution or both aqueous solutions. Further, it is preferable to exist for at least 50% of the nucleation step, and more preferably for 70% or more. The compound represented by the above general formula may be added as a powder or dissolved in a solvent such as methanol.
[0153]
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 (for example, the temperature at the start of nucleation is 25 ° C. It is preferable to control the temperature within the above temperature range even when the temperature is gradually raised and the temperature at the end of nucleation is 40 ° C.) and vice versa.
[0154]
The concentration of the aqueous silver salt solution and aqueous halide solution used for nucleation is preferably 3.5 mol / L or less, and more preferably used in a low concentration range of 0.01 to 2.5 mol / L. The addition rate of silver ions during nucleation was 1.5 × 10 5 per liter of reaction solution.^-3~ 3.0 × 10^-1Mol / min is preferred, more preferably 3.0 × 10^-3~ 8.0 × 10^-2Mol / min.
[0155]
The pH at the time of nucleation can be set in the range of 1.7 to 10, but the pH on the alkali side is preferably pH 2 to 6 in order to broaden the particle size distribution of nuclei to be formed. Moreover, 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.
[0156]
The silver halide grains used in the present invention may be added to the photosensitive layer by any method. At this time, the silver halide grains are arranged so as to be close to a reducible silver source (aliphatic carboxylic acid silver salt). Is preferred.
[0157]
The silver halide used in the present invention is prepared in advance, and this is added to a solution for preparing aliphatic carboxylic acid silver salt grains. Since the process can be handled separately, it is preferable in terms of production control. However, as described in British Patent 1,447,454, when preparing aliphatic carboxylic acid silver salt particles, halogen components such as halide ions are added. By coexisting with an aliphatic carboxylate silver salt-forming component and injecting silver ions therein, the aliphatic carboxylate silver salt particles can be produced almost simultaneously. It is also possible to prepare silver halide grains by converting a halogen-containing silver salt into an aliphatic carboxylic acid silver salt and converting the aliphatic carboxylic acid silver salt. That is, a silver halide-forming component is allowed to act on a solution or dispersion of an aliphatic carboxylic acid silver salt prepared in advance, or a sheet material containing the aliphatic carboxylic acid silver salt, so that a part of the aliphatic carboxylic acid silver salt is removed. It can also be converted to photosensitive silver halide.
[0158]
Examples of silver halide grain forming components include inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. 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. Inorganic halides such as ammonium, for example, onium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, such as iodoform, bromoform, carbon tetrachloride, 2-bromo-2-methylpropane, etc. Halogenated hydrocarbons of -N-halogen compounds such as bromosuccinimide, N-bromophthalimide, N-bromoacetamide, and others, such as triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone, etc. is there. Thus, a silver halide can also be prepared by converting a part or all of silver in an organic acid silver salt into silver halide by a reaction between an organic acid silver and a halogen ion. Moreover, you may use together the silver halide grain manufactured by converting a part of aliphatic carboxylic acid silver salt into the silver halide prepared separately.
[0159]
These silver halide grains are separately prepared silver halide grains, 0.001 to 0.7 mol per 1 mol of aliphatic carboxylic acid silver salt, and silver halide grains obtained by conversion of aliphatic carboxylic acid silver salt. Preferably 0.03-0.5 mol is used.
[0160]
The silver halide grains used in the present invention preferably contain transition metal ions belonging to Groups 6 to 11 of the Periodic Table of Elements. As the 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. Although these metal ions may introduce a metal salt into silver halide as it is, they can be introduced into silver halide in the form of a metal complex or complex ion. The preferred content is 1 x 10 per mole of silver.^-9From mole to 1 × 10^-2The molar range is preferred, 1 × 10^-8~ 1x10^-FourThe range of is more preferable. In the present invention, the transition metal complex or complex ion is preferably represented by the following general formula.
[0161]
General formula [ML₆]^m
In the formula, M represents a transition metal selected from Group 6 to 11 elements in the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include halogen ion (fluorine ion, chlorine ion, bromine ion, iodine ion), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide, and aco. A ligand, nitrosyl, thionitrosyl and the like can be mentioned, and ako, nitrosyl, thionitrosyl and the like are preferable. When an acoligand is present, it preferably occupies one or two of the ligands. L may be the same or different.
[0162]
The compounds providing these metal ions or complex ions are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening , May be added at any stage before or after chemical sensitization, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, most preferably Preferably, it is added at the stage of nucleation. In addition, it may be divided and added several times, or it can be uniformly contained in the silver halide grains. JP-A-63-29603, JP-A-2-306236, 3 As described in JP-A Nos. 167545, 4-76534, 6-110146, 5-273683, etc., the particles can be contained with a distribution.
[0163]
These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or the silver salt solution and the halide solution are mixed simultaneously. When adding a third aqueous solution, a method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of introducing an aqueous solution of a required amount of a metal compound into a reaction vessel during grain formation, or a silver halide preparation There is a method of adding and dissolving another silver halide grain that has been previously doped with metal ions or complex ions. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution. When added to the particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particle, during or after the physical ripening, or at the chemical ripening.
[0164]
Separately prepared photosensitive silver halide grains can be desalted by a known desalting method such as noodle method, flocculation method, ultrafiltration method, electrodialysis method, etc., but can also be used without desalting. .
[0165]
The silver salt photothermographic dry imaging material of the present invention forms a photographic image by heat development processing, and includes aliphatic carboxylic acid silver salt, photosensitive silver halide grains, a crosslinking agent, a reducing agent, and silver if necessary. It is preferable that a color tone agent for adjusting the color tone is usually contained in a dispersed state in an (organic) binder matrix.
(Coloring agent)
Examples of suitable toning agents are disclosed in RD 17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136 and 4,021,249. Particularly preferred color tones are phthalazinone or a combination of phthalazine and phthalic acids and phthalic anhydrides.
[0166]
Incidentally, with regard to the color tone of the output image for conventional medical diagnosis, it is said that the image tone of the cold tone is more likely to obtain a more accurate diagnostic observation result of the recorded image for the reader of the X-ray photograph. Here, the cool image tone is a pure black tone or a bluish black tone of a black image, and the warm image tone is a black tone of a black image having a brownish tone. To tell.
[0167]
The terms “more cold” and “more warm” relating to the color tone refer to the hue angle h at the minimum density Dmin and optical density D = 1.0._abIs required. Hue angle h_abIs a color space with a perceptually uniform rate recommended in 1976 by the International Commission on Illumination (CIE).^*a^*b^*Color coordinate a of color space^*, B^*Is obtained by the following equation.
[0168]
h_ab= Tan-1 (b^*/ A^*)
In the present invention, a preferred hue angle h_abThe range is 180 ° <h_ab<270 °, more preferably 200 ° <h_ab<270 °, most preferably 220 ° <h_ab<260 °.
[0169]
In the present invention, the surface layer of the silver salt photothermographic dry imaging material (even when the photosensitive layer side or the non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support sandwiched) is handled before development or thermal development. It is preferable to contain a matting agent in order to prevent the subsequent image from being damaged, and it is preferable to contain 0.1 to 30% by mass with respect to the binder.
[0170]
The material of the matting agent may be either organic or inorganic. Examples of inorganic substances include silica described in Swiss Patent No. 330,158 and the like, glass powder described in French Patent No. 1,296,995 and the like, and alkali described in British Patent No. 1,173,181 and the like. Earth metals or carbonates such as cadmium and zinc can be used as the matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037 and the like, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, and Japanese Patent Publication No. 44-3643. Polyvinyl alcohol described, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in US Pat. No. 3,079,257, US Pat. No. 3,022,169 etc. An organic matting agent such as a polycarbonate can be used.
[0171]
The matting agent preferably has an average particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm. The coefficient of variation of the particle size distribution is preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less.
[0172]
Here, the variation coefficient of the particle size distribution is a value represented by the following equation.
(Standard deviation of particle size) / (Average value of particle size) × 100
The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed and applied in advance in the coating solution, or a method in which the matting agent is sprayed after the coating solution is applied and before drying is completed. May be. When a plurality of types of matting agents are added, both methods may be used in combination.
(Support)
Examples of the support material used in the silver salt photothermographic dry imaging material of the present invention include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (for example, aluminum), etc. In terms of handling, a material that can be processed into a flexible sheet or roll is suitable. Therefore, as a support in the silver salt photothermographic dry imaging material of the present invention, a plastic film (for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, polyimide film, cellulose triacetate film, polycarbonate film, etc. In the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferable. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.
[0173]
In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be included in the constituent layers in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat. In the present invention, the conductive compounds described in US Pat. No. 5,244,773, columns 14 to 20 are preferably used.
(Formation of silver salt photothermographic dry imaging materials)
The silver salt photothermographic dry imaging material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is provided on the photosensitive layer for the purpose of protecting the photosensitive layer, and a back coat layer is provided on the opposite side of the support to prevent sticking between the photosensitive materials or in the photosensitive material roll. It is preferred that Binders used in these protective layers and backcoat layers have a glass transition point higher than that of the heat-developable layer, and polymers such as cellulose acetate and cellulose acetate butyrate are less likely to be scratched or deformed, such as cellulose acetate and cellulose acetate butyrate. It is chosen from among them. For gradation adjustment and the like, two or more photosensitive layers may be provided on one side of the support or one or more layers on both sides of the support.
[0174]
In the silver salt photothermographic dry imaging material of the present invention, a filter layer is formed on the same side as or opposite to the photosensitive layer in order to control the amount of light transmitted through the photosensitive layer or the wavelength distribution, or a dye is formed on the photosensitive layer. Or it is preferable to contain a pigment.
[0175]
As the dye used, known compounds that absorb light in various wavelength regions can be used depending on the color sensitivity of the photosensitive material.
[0176]
For example, when the silver salt photothermographic dry imaging material of the present invention is used as an image recording material by infrared light, a squarylium dye having a thiopyrylium nucleus as disclosed in Japanese Patent Application No. 11-255557 (this specification) Used as a thiopyrylium squarylium dye) and a squarylium dye having a pyrylium nucleus (referred to herein as a pyrylium squarylium dye), or a thiopyrylium croconium dye similar to a squarylium dye, or a pyrylium croconium dye. It is preferable to do.
[0177]
The compound having a squarylium nucleus is a compound having 1-cyclobutene-2-hydroxy-4-one in the molecular structure, and the compound having a croconium nucleus is 1-cyclopentene-2-hydroxy- in the molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these pigments are collectively referred to as squarylium dyes for convenience.
[0178]
As the dye, a compound described in JP-A-8-201959 is also preferable.
The silver salt photothermographic dry imaging material of the present invention is formed by preparing a coating liquid in which the above-described constituent layers are dissolved or dispersed in a solvent, and applying a plurality of these coating liquids simultaneously, followed by heat treatment. It is preferable. Here, "multiple simultaneous multi-layer coating" means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and when coating this onto a support, each layer is individually coated and dried repeatedly. In other words, it means that each constituent layer can be formed in such a state that the multilayer coating and drying can be performed simultaneously. That is, the upper layer is provided before the remaining amount of the total solvent in the lower layer reaches 70% by mass or less.
[0179]
There are no particular restrictions on the method of applying multiple layers of each constituent layer simultaneously, and for example, a known method such as a bar coater method, curtain coating method, dipping method, air knife method, hopper coating method, or extrusion coating method may be used. Can do. Of these, a pre-weighing type coating method called an extrusion coating method is more preferable. Since the extrusion coating method does not volatilize on the slide surface unlike the slide coating method, it is suitable for precision coating and organic solvent coating. Although this coating method has been described on the side having the photosensitive layer, the same applies to the case of coating with undercoating when providing the backcoat layer.
[0180]
In the present invention, the amount of coated silver is preferably selected in accordance with the purpose of the silver salt photothermographic imaging material, but 0.6 to 2.5 g / m for medical images.²Is preferred. Furthermore, 1.0 to 1.7 g / m²Is preferred. Among the applied silver amount, those derived from silver halide preferably occupy 2 to 18%, more preferably 3 to 15%, based on the total silver amount.
[0181]
In the present invention, the coating density of silver halide grains having a diameter of 0.01 μm or more (equivalent particle diameter equivalent to sphere) is 1 × 10¹⁴~ 1x10¹⁸Pieces / m²Is preferred. Furthermore, 1x10¹⁵~ 1x10¹⁷Pieces / m²Is preferred.
[0182]
Furthermore, the coating density of the aliphatic carboxylic acid silver salt of the present invention is 10 μm per silver halide grain having a particle diameter of 0.01 μm or more (equivalent particle diameter equivalent to sphere)^-17-10^-15g, or even 10^-16-10^-14g is preferred.
[0183]
When coated under the conditions within the above range, it is preferable from the viewpoint of the optical maximum density of the silver image per fixed coated silver amount, that is, the silver coating amount (covering power) and the color tone of the silver image. Results are obtained.
(Image recording method)
In the present invention, the development conditions vary depending on the equipment, equipment, or means used, but typically involve heating the imagewise exposed silver salt photothermographic dry imaging material at a suitable high temperature. . The latent image obtained after the exposure is obtained at a moderately high temperature (for example, about 80 to 200 ° C., preferably about 100 to 200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). The dry imaging material can be developed by heating. When the heating temperature is 80 ° C. or lower, sufficient image density cannot be obtained in a short time. When the heating temperature is 200 ° C. or higher, the binder is melted, and not only the image itself, such as transfer to a roller, but also adversely affects the transportability and the developing machine. Effect. By heating, a silver image is generated by a redox reaction between the aliphatic carboxylic acid silver salt (which functions as an oxidizing agent) and the reducing agent. This reaction process proceeds without any supply of treatment liquid such as water from the outside.
[0184]
The heating device, apparatus, and means may be a heating means typical as a heat generator using a hot plate, iron, hot roller, carbon, white titanium, or the like. More preferably, the silver salt photothermographic dry imaging material provided with the protective layer is subjected to the heat treatment by bringing the surface having the protective layer into contact with the heating means in order to perform uniform heating, thermal efficiency and workability. In view of the above, it is preferable that the surface is conveyed while being brought into contact with a heat roller, and heat-treated to develop.
[0185]
In the exposure of the silver salt photothermographic dry imaging material of the present invention, it is desirable to use an appropriate light source for the color sensitivity imparted to the photosensitive material. For example, when the photosensitive material is sensitive to infrared light, it can be applied to any light source as long as it is in the infrared light range, but the laser power is high and the photosensitive material can be transparent. In view of the above, an infrared semiconductor laser (780 nm, 820 nm) is more preferably used.
[0186]
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 formed by the exposure surface of the photosensitive material and the scanning laser beam is not substantially perpendicular.
[0187]
Here, “substantially not perpendicular” means that the angle closest to the vertical during laser scanning is preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably 65 to 84 degrees. , And most preferably 70 to 82 degrees.
[0188]
The beam spot diameter on the photosensitive material exposure surface when the laser beam is scanned onto the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that the smaller the spot diameter, the smaller the angle of deviation of the laser incident angle from the vertical. 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 related to reflected light such as generation of interference fringe-like unevenness.
[0189]
As a second method, the exposure in the present invention is preferably performed using a laser scanning exposure machine that emits a scanning laser beam that is a vertical multi. Compared with a single longitudinal mode scanning laser beam, image quality degradation such as occurrence of interference fringe-like unevenness is reduced.
[0190]
In order to make it vertically multi-ply, methods such as using return light by multiplexing and applying high-frequency superposition are preferable. 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.
[0191]
In the image recording methods of the first and second aspects described above, as lasers used for scanning exposure, generally well-known solid lasers such as ruby laser, YAG laser, and glass laser; HeNe laser, Ar ion Laser, Kr ion laser, CO₂Laser, CO laser, HeCd laser, N₂Gas laser such as laser and excimer laser; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP₂Lasers, semiconductor lasers such as GaSb lasers; chemical lasers, dye lasers, etc. can be selected and used in a timely manner, but among these, semiconductor lasers with wavelengths of 600-1200 nm are used due to maintenance and light source size problems. It is preferable to use it. In addition, in a laser used in a laser imager or a laser image setter, the beam spot diameter on the material exposure surface when scanned with a silver salt photothermographic dry imaging material is generally 5 to 75 μm as a minor axis diameter, The major axis diameter is in the range of 5 to 100 μm, and the laser beam scanning speed can be set to an optimum value for each photosensitive material depending on the sensitivity and laser power at the laser oscillation wavelength unique to the silver salt photothermographic dry imaging material.
[0192]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.
[0193]
Example 1
<< Preparation of Photographic Support >>
0.5 kV · A · min / m on one surface of polyethylene terephthalate film base (thickness: 175 μm) colored blue with a concentration of 0.170²After the corona discharge treatment, an undercoat layer “a” was coated thereon using the following undercoat coating solution A so that the dry film thickness was 0.2 μm. Furthermore, the other surface is similarly 0.5 kV · A · min / m.²After the corona discharge treatment, the undercoat coating solution B below was used to coat the undercoat layer b so that the dry film thickness was 0.1 μm. After that, 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.
(Undercoating liquid A)
270 g of copolymer latex liquid (solid content 30%) of 30% by mass of n-butyl acrylate, 20% by mass of t-butyl acrylate, 25% by mass of styrene and 25% by mass of 2-hydroxyethyl acrylate, surfactant (UL-1 ) 0.6 g and methyl cellulose 0.5 g were mixed. Further, 1.3 g of silica particles (Syloid 350, manufactured by Fuji Silysia) was added to 100 g of water, and dispersion treatment was performed for 30 minutes with an ultrasonic disperser (manufactured by ALEX Corporation, Ultrasonic Generator, frequency 25 kHz, 600 W). The dispersion liquid was added, and finally it was made up to 1000 ml with water to obtain an undercoat coating liquid A.
(Preparation of colloidal tin oxide dispersion)
A homogeneous solution was prepared by dissolving 65 g of stannic chloride hydrate in 2000 ml of a water / ethanol mixed solution. This was then boiled to obtain a coprecipitate. The generated precipitate was taken out by decantation and washed several times with distilled water. Silver nitrate is dropped into distilled water from which the precipitate has been washed, and after confirming that there is no reaction of chlorine ions, distilled water is added to the washed precipitate to make a total volume of 2000 ml. Furthermore, 40 ml of 30% aqueous ammonia was added, the aqueous solution was heated, and concentrated to a volume of 470 ml to prepare a colloidal tin oxide dispersion.
(Undercoating liquid B)
Copolymer latex liquid (solid content 30) of 37.5 g of the colloidal tin oxide dispersion, 20% by mass of n-butyl acrylate, 30% by mass of t-butyl acrylate, 27% by mass of styrene and 28% by mass of 2-hydroxyethyl acrylate. %) 3.7 g, n-butyl acrylate 40 mass%, styrene 20 mass%, glycidyl methacrylate 40 mass% copolymer latex liquid (solid content 30%) 14.8 g and surfactant (UL-1) 0. 1 g was mixed and finished to 1000 ml with water to obtain an undercoat coating solution B.
[0194]
Embedded image

[0195]
<Back side application>
While stirring 830 g of methyl ethyl ketone (MEK), 84.2 g of cellulose acetate butyrate (Eastman Chemical, CAB381-20) and 4.5 g of a polyester resin (Bostic, VitelPE2200B) were added and dissolved. Next, 0.30 g of infrared dye 1 was added to the dissolved liquid, and 4.5 g of F-type active agent (Asahi Glass Co., Surflon KH40) and F-type active agent (Dainippon Ink, Inc.) dissolved in 43.2 g of methanol were further added. Co., MegaFag F120K) 2.3 g was added and stirred well until dissolved. Finally, 75 g of silica (WR Grace, Syloid 64X6000) dispersed in MEK at a concentration of 1% by mass with a dissolver type homogenizer was added and stirred to prepare a coating solution for the back surface side.
[0196]
Embedded image

[0197]
The back surface coating solution thus prepared was applied and dried by an extrusion coater so that the dry film thickness was 3.5 μm. It dried for 5 minutes using the drying air with a drying temperature of 100 degreeC, and dew point temperature of 10 degreeC.
<< Preparation of photosensitive silver halide emulsion A >>
A1
Phenylcarbamoylated gelatin 88.3g
Compound (A) (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Finish to 5429 ml with water
B1
0.67 mol / L silver nitrate aqueous solution 2635 ml
C1
Potassium bromide 51.55g
Potassium iodide 1.47g
Finish to 660ml with water
D1
Potassium bromide 154.9g
4.41 g of potassium iodide
Iridium chloride (1% solution) 0.93ml
Finish to 1982ml with water
E1
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount
F1
Potassium hydroxide 0.71g
Finish to 20ml with water
G1
56% acetic acid aqueous solution 18.0 ml
H1
Anhydrous sodium carbonate 1.72 g
Finish to 151ml with water
Compound (A):

Using the mixing stirrer shown in Japanese Patent Publication Nos. 58-58288 and 58-58289, ¼ amount of the solution (B1) and the total amount of the solution (C1) were adjusted to a temperature of 39 ° C. and a pAg of 8.09. While controlling, it was added in 4 minutes and 45 seconds by the simultaneous mixing method, and nucleation was performed. After 1 minute, the entire amount of solution (F1) was added. During this time, the pAg was adjusted as appropriate using the aqueous solution (E1). After 6 minutes, 3/4 amount of the solution (B1) and the total amount of the solution (D1) were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling the temperature at 39 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (G1) was added, and the silver halide emulsion was precipitated. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 L of water was further added, and after stirring, the silver halide emulsion was precipitated. After leaving 1500 ml of the sedimented portion and removing the supernatant, 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 that the amount was 1161 g per mole of silver to obtain an emulsion.
[0198]
This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.053 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.
[0199]
Next, 240 ml of sulfur sensitizer S-5 (0.5% methanol solution) was added to the above emulsion, and gold sensitizer Au-5 corresponding to 1/20 mol of this sensitizer was added, and the mixture was heated to 55 ° C. The mixture was stirred for 120 minutes for chemical sensitization. This is designated as photosensitive silver halide emulsion A.
[0200]
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[0201]
<< Preparation of powdered aliphatic carboxylic acid silver salt A >>
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 mol / L sodium hydroxide aqueous solution was added, and 6.9 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the sodium fatty acid solution at 55 ° C., 45.3 g of the above photosensitive silver halide emulsion A and 450 ml of pure water were added and stirred for 5 minutes.
[0202]
Next, 702.6 ml of a 1 mol / L silver nitrate solution was added over 2 minutes and stirred for 10 minutes to obtain an aliphatic carboxylic acid silver salt dispersion. Thereafter, the obtained aliphatic carboxylic acid silver salt dispersion was transferred to a water-washing vessel, deionized water was added and stirred, and then allowed to stand to float and separate the aliphatic carboxylic acid silver salt dispersion. Was removed. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 50 μS / cm, and centrifugal dehydration was performed. Then, the resulting cake-like aliphatic carboxylic acid silver salt was used as a flash-type dryer flash jet dryer. By using (made by Seishin Enterprise Co., Ltd.) under the operating conditions of nitrogen gas atmosphere and dryer inlet hot air temperature, it was dried until the water content became 0.1% to obtain powdered aliphatic carboxylic acid silver salt A. An infrared moisture meter was used to measure the water content of the aliphatic carboxylic acid silver salt composition. The behenic acid ratio was 54% by mass.
<< Preparation of powdered aliphatic carboxylic acid silver salt B >>
Powdered aliphatic carboxylic acid silver salt B was prepared in the same manner as powdered aliphatic carboxylic acid silver salt A except that behenic acid 217 g, arachidic acid 20.0 g, and stearic acid 17.3 g were used, and the dissolution temperature was 90 ° C. The behenic acid ratio was 85% by mass.
<< Preparation of powdered aliphatic carboxylic acid silver salt C >>
Powdered aliphatic carboxylic acid silver salt The same as powdered aliphatic carboxylic acid silver salt A except that 259.3 g of behenic acid (2% by mass contained arachidic acid) was used and the dissolution temperature was 90 ° C. C was produced. The behenic acid ratio was 98% by mass.
<< Preparation of powdered aliphatic carboxylic acid silver salt D >>
Powdered aliphatic carboxylate in the same manner as powdered aliphatic carboxylic acid silver salt A except that behenic acid 217 g, arachidic acid 20.0 g, and stearic acid 17.3 g were used, the dissolution temperature was changed to 90 ° C., and sodium hydroxide was changed to potassium hydroxide. A carboxylic acid silver salt D was prepared. The behenic acid ratio was 85% by mass.
<< Preparation of powdered aliphatic carboxylic acid silver salt E >>
Powdered aliphatic except that 217 g of behenic acid, 20.0 g of arachidic acid and 17.3 g of stearic acid were used, the dissolution temperature was changed to 90 ° C., and sodium hydroxide was changed to sodium hydroxide: potassium hydroxide = 1: 9 (molar ratio). Powdered aliphatic carboxylic acid silver salt E was produced in the same manner as carboxylic acid silver salt A. The behenic acid ratio was 85% by mass.
<< Preparation of powdered aliphatic carboxylic acid silver salt F >>
Powdered aliphatic except that 217 g of behenic acid, 20.0 g of arachidic acid and 17.3 g of stearic acid were used, the dissolution temperature was 90 ° C., and sodium hydroxide was changed to sodium hydroxide: potassium hydroxide = 75: 25 (molar ratio). Powdered aliphatic carboxylic acid silver salt F was produced in the same manner as carboxylic acid silver salt A. The behenic acid ratio was 85% by mass.
<< Preparation of Preliminary Dispersions A to F >>
Dissolve 14.57 g of polyvinyl butyral resin (manufactured by Solussia, B-79) in 1457 g of MEK and gradually dissolve 500 g of powdered aliphatic carboxylic acid silver salt A while stirring with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. A preliminary dispersion A was prepared by adding to the mixture and mixing well.
[0203]
Preliminary dispersions BF were prepared in exactly the same manner except that powdered aliphatic carboxylic acid silver salts BF were used instead of powdered aliphatic carboxylic acid silver salt A.
<< Preparation of photosensitive emulsion dispersions A to F >>
Media type disperser DISPERMAT SL- filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Torayserum manufactured by Toray) so that the residence time in the mill is 1.5 minutes using a pump. Photosensitive emulsion dispersion A was prepared by supplying to C12EX type (VMA-GETZMANN) and dispersing at a mill peripheral speed of 8 m / s.
[0204]
Photosensitive emulsion dispersions B to F were prepared in the same manner except that the preliminary dispersions B to F were used instead of the preliminary dispersion A.
<< Preparation of stabilizer liquid >>
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate in 4.97 g of methanol.
<< Preparation of infrared sensitizing dye liquid A >>
19.2 mg of infrared sensitizing dye 1, 1.488 g 2-chloro-benzoic acid, 2.7779 g stabilizer 2 and 365 mg 5-methyl-2-mercaptobenzimidazole in 31.3 ml MEK in the dark Infrared sensitizing dye solution A was prepared.
<< Preparation of Additive Liquid a >>
27.98 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (developer A) as a developer and 1.54 g of 4-methylphthalic acid; 48 g of the infrared dye 1 was dissolved in 110 g of MEK to obtain an additive solution a.
<< Preparation of additive liquid b >>
3.56 g of antifoggant 2 and 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain additive solution b.
<< Preparation of photosensitive layer coating solution A >>
In an inert gas atmosphere (97% nitrogen), the photosensitive emulsion dispersion A (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, 390 μl of antifoggant 1 (10% methanol solution) was added, Stir for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of a stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl butyral resin (B-79, manufactured by Solusia) was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added. And stirred for 15 minutes. While further stirring, 12.43 g of additive solution a, 1.6 ml of Desmodur N3300 / Movey aliphatic isocyanate (10% MEK solution), and 4.27 g of additive solution b were sequentially added and stirred for photosensitivity. A layer coating solution A was obtained.
<Preparation of matting agent dispersion>
Cellulose acetate butyrate (Eastman Chemical Co., 7.5 g CAB171-15) was dissolved in 42.5 g of MEK, and 5 g of calcium carbonate (Speciality Minerals, Super-Pflex 200) was added thereto, and a dissolver type homogenizer was used. Dispersion was performed at 8000 rpm for 30 minutes to prepare a matting agent dispersion.
<< Preparation of surface protective layer coating liquid >>
While stirring MEK865g, cellulose acetate butyrate (Eastman Chemical Co., CAB171-15) 96g, polymethylmethacrylic acid (Rohm & Haas Co., Paraloid A-21) 4.5g, vinyl sulfone compound (VSC) 1 0.5 g, 1.0 g of benztriazole, and 1.0 g of F-based activator (Asahi Glass Co., Surflon KH40) were added and dissolved. Next, 30 g of the above matting agent dispersion was added and stirred to prepare a surface protective layer coating solution.
[0205]
Embedded image

[0206]
<< Production of Silver Salt Photothermographic Dry Imaging Material Sample 101 >>
The photosensitive layer coating solution A and the surface protective layer coating solution were simultaneously applied by using a known extrusion coater. The photosensitive layer is coated with a silver coating amount of 1.5 g / m.²The surface protective layer was formed so as to have a dry film thickness of 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. to prepare a silver salt photothermographic dry imaging material sample 101 (simply referred to as sample 101 in Table 2).
[0207]
  Except that the photosensitive emulsion dispersion in the photosensitive layer coating solution, the binder of the photosensitive layer, and the type of reducing agent were changed as shown in Table 2, the same procedure as in Sample 101 was performed.As described in Table 2Sample 102Less thanWas made.
[0208]
The measurement results were evaluated by sensitivity (reciprocal of the ratio of the exposure amount giving a density 1.0 higher than the unexposed portion) and fog, and are shown in Table 2 as relative values with the sensitivity of the sample 101 being 100.
<Evaluation>
<Measurement of thermal transition temperature>
On the Teflon (R) plate, the photosensitive layer coating solution and the surface protective layer coating solution having the same composition as described above are applied and dried so as to satisfy the same conditions using a wire bar. After exposure and development in the same manner under the conditions, the constituent layer coated from the Teflon (R) plate was peeled off. About 10 mg of the peeled sample was loaded into an aluminum pan, and the thermal transition temperature of each sample was measured according to JIS K7121 using a differential scanning calorimeter (EXSTAR6000, manufactured by Seiko Denshi). As temperature rising conditions in the measurement, the temperature was raised from 0 to 200 ° C. at 10 ° C./min, cooling to 0 ° C. was carried out at 20 ° C./min, and this operation was repeated twice to obtain the heat transition temperature. Asked.
<Measurement of fog density fluctuation rate>
A sample that has been heat-developed by the same method as the above sensitivity measurement is placed in a 45 ° C., 55% RH environment with a commercially available white fluorescent lamp so that the illuminance on the sample surface is 500 lux, and irradiation is continued for 3 days. gave. Minimum concentration of sample irradiated with fluorescent lamp (D₂) And the minimum concentration (D₁) Were measured, and the fog density fluctuation rate (%) was calculated from the following equation.
[0209]
Fog density fluctuation rate = (D₂-D₁) / D₁× 100 (%)
<Evaluation of image preservation>
A sample that had been heat-developed by the same method as the above sensitivity measurement was left in an environment of 25 ° C. and 45 ° C. for 3 days, then the change in maximum density was measured, and the rate of change in image density was measured as follows. Was a measure of image preservation.
[0210]
Image density change rate = maximum density of sample stored at 45 ° C./maximum density of sample stored at 25 ° C. × 100 (%)
<Evaluation of storage stability over time>
After the obtained sample was stored for 10 days under the following two conditions, exposure and development were performed in the same manner as the sensitivity measurement, respectively, and the sensitivity of the obtained image was evaluated. The rate of change in sensitivity under condition B was determined from the following and used as a measure of storage stability over time.
[0211]
Condition A: 25 ° C., 55% RH
Condition B: 40 ° C., 80% RH
Sensitivity change rate = sensitivity in condition B / sensitivity in condition A × 100 (%)
<Measurement of hue angle>
Hue angle h_abIs measured using a JIS Z8720 standard light source D65 as a colorimetric light source as a colorimetric light source and a spectral colorimeter CM-508d (manufactured by Minolta Co., Ltd.). ) And measured.
<Filter supplement (sublimation from film)>
The film subjected to exposure so that the film density becomes 3.5 or more was thermally developed for 10,000 sheets, and then evaluated in four stages according to the mass of supplements captured by a filter in the developing machine.
[0212]
1 ... very many
2 ... more
3 ... There are few supplements
4 ... Very few supplements
[0213]
[Table 2]

[0214]
* 1: Photosensitive emulsion dispersion
* 2: Photosensitive layer binder
* 3: Reducing agent type
* 4: Thermal transition temperature (° C) of the photosensitive layer
* 5: Fog density fluctuation rate (%)
* 6: Filter supplement
* 7: Hue angle h_ab: Minimum density part
* 8: Hue angle h_ab: D = 1.0 part
As is clear from Table 2, the silver salt photothermographic dry imaging material of the present invention has high sensitivity and low fog as compared with the comparative example, and is excellent in image storability after development and storability over time. It can be seen that there are also very few sublimates from. The sample of the present invention also has a hue angle value specified by JIS Z8729 that exceeds 180 ° and less than 270 °, has a cold image tone, and can provide an appropriate output image as a diagnostic image. I understood.
[0215]
Example 2
A silver salt photothermographic dry imaging material sample was prepared in the same manner as in Example 1 except for the following.
<< Preparation of powdered aliphatic carboxylic acid silver salt G >>
In 4720 ml of pure water, 217 g of behenic acid, 20.0 g of arachidic acid, and 17.3 g of stearic acid were dissolved at 90 ° C. Next, 540.2 ml of 1.5 mol / L sodium hydroxide: potassium hydroxide aqueous solution (molar ratio = 1: 9) was added and 6.9 ml of concentrated nitric acid was added. Obtained. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., 347 ml of t-butyl alcohol was added and stirred for 20 minutes, and then the photosensitive silver halide emulsion A (45.3 g) obtained in Example 1 and pure water were used. 450 ml was added and stirred for 5 minutes.
[0216]
Otherwise, powdered aliphatic carboxylic acid silver salt G was prepared in the same manner as powdered aliphatic carboxylic acid silver salt A of Example 1.
<< Preparation of powdered aliphatic carboxylic acid silver salt H >>
In 4720 ml of pure water, 217 g of behenic acid, 20.0 g of arachidic acid, 17.3 g of stearic acid, and 17.0 g of iso-arachidic acid were dissolved at 90 ° C. Next, 540.2 ml of 1.5 mol / L sodium hydroxide: potassium hydroxide aqueous solution (molar ratio = 1: 9) was added and 6.9 ml of concentrated nitric acid was added. Obtained. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., the photosensitive silver halide emulsion A (45.3 g) obtained in Example 1 and 450 ml of pure water were added and stirred for 5 minutes.
[0217]
Otherwise, powdered aliphatic carboxylic acid silver salt H was prepared in the same manner as powdered aliphatic carboxylic acid silver salt A of Example 1.
<< Preparation of powdered aliphatic carboxylic acid silver salt I >>
In 4720 ml of pure water, 217 g of behenic acid, 20.0 g of arachidic acid, 17.3 g of stearic acid, and 6.0 g of oleic acid were dissolved at 90 ° C. Next, 540.2 ml of a 1.5 mol / L sodium hydroxide: potassium hydroxide aqueous solution (molar ratio = 1: 9) was added and 6.9 ml of concentrated nitric acid was added. Obtained. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., the photosensitive silver halide emulsion A (45.3 g) obtained in Example 1 and 450 ml of pure water were added and stirred for 5 minutes.
[0218]
Otherwise, the powdered aliphatic carboxylic acid silver salt I was prepared in the same manner as the powdered aliphatic carboxylic acid silver salt A of Example 1.
<< Preparation of powdered aliphatic carboxylic acid silver salt J >>
In 4720 ml of pure water, 217 g of behenic acid, 20.0 g of arachidic acid, 17.3 g of stearic acid, and 1.5 g of polyvinyl alcohol (PVA-205 manufactured by Kuraray Co., Ltd.) were dissolved at 90 ° C. Next, 540.2 ml of 1.5 mol / L sodium hydroxide: potassium hydroxide aqueous solution (molar ratio = 1: 9) was added and 6.9 ml of concentrated nitric acid was added. Obtained. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., the photosensitive silver halide emulsion A (45.3 g) obtained in Example 1 and 450 ml of pure water were added and stirred for 5 minutes.
[0219]
Otherwise, the powdered aliphatic carboxylic acid silver salt J was prepared in the same manner as in Example 1 of the powdered aliphatic carboxylic acid silver salt A.
<< Preparation of powdered aliphatic carboxylic acid silver salt K >>
In 4720 ml of pure water, 217 g of behenic acid, 20.0 g of arachidic acid, and 17.3 g of stearic acid were dissolved at 90 ° C. Next, 540.2 ml of 1.5 mol / L sodium hydroxide: potassium hydroxide aqueous solution (molar ratio = 1: 9) was added, 6.9 ml of concentrated nitric acid was added, and then 30% by mass of n-butyl acrylate, t-butyl. A copolymer latex solution (solid content 30%) of 20% by mass of acrylate, 25% by mass of styrene and 25% by mass of 2-hydroxyethyl acrylate was added and cooled to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., the photosensitive silver halide emulsion A (45.3 g) obtained in Example 1 and 450 ml of pure water were added and stirred for 5 minutes.
[0220]
Otherwise, powdered aliphatic carboxylic acid silver salt K was prepared in the same manner as powdered aliphatic carboxylic acid silver salt A of Example 1.
<< Preparation of preliminary dispersions G to K >>
It was prepared in the same manner as in Example 1 except that the powdered aliphatic carboxylic acid silver salts G to K were used.
<< Preparation of photosensitive emulsion dispersions G to K >>
It was prepared in the same manner as in Example 1 except that the preliminary dispersions G to K were changed.
<< Preparation of photosensitive layer coating solution G >>
In the same manner as in the photosensitive layer coating solution A of Example 1, a photosensitive layer coating solution G was prepared using the photosensitive emulsion dispersion G.
<< Preparation of Silver Salt Photothermographic Dry Imaging Material Samples 201-205 >>
A sample 201 was produced in the same manner as in Example 1 using the photosensitive layer coating solution G and the surface protective layer coating solution of Example 1.
[0221]
Samples 202 to 205 were prepared in the same manner as Sample 201 except that the photosensitive emulsion dispersion in the photosensitive layer coating solution, the binder of the photosensitive layer, and the type of reducing agent were changed to those described in Table 3.
<Measurement of particle size and thickness of aliphatic carboxylic acid silver salt>
The dispersed aliphatic carboxylic acid silver salt is diluted and dispersed on a grid with a carbon support film, photographed directly at a magnification of 5000 using a transmission electron microscope (JEOL Ltd., 2000FX type), and negative with a scanner Was taken as a digital image, and 300 particle sizes were measured using an image processing apparatus LUZEX III (manufactured by Nicole), and the average value was determined.
[0222]
Next, in order to obtain the thickness, the photosensitive layer coated on the support is attached to the holder with an adhesive, and a diamond knife is used in a direction perpendicular to the support surface to form an ultrathin film having a thickness of 0.1 to 0.2 μm. Sections were prepared. An ultra-thin slice is supported on a copper mesh, transferred onto a carbon film that has been made hydrophilic by glow discharge, and cooled to −130 ° C. or lower with liquid nitrogen, using the above transmission electron microscope, at a magnification of 5,000 to 40, A bright field image was observed at 000 and the image was recorded on film. The thickness of 300 images of this image was measured using an image processing apparatus LUZEX III (manufactured by Nicole), and the average value was obtained.
[0223]
Exposure, development processing and various evaluations were performed in the same manner as in Example 1.
[0224]
[Table 3]

[0225]
* 1: Photosensitive emulsion dispersion
* 2: Silver particle size of aliphatic carboxylic acid (μm)
* 3: Aliphatic carboxylate film thickness (μm)
* 4: Photosensitive layer binder
* 5: Reducing agent type
* 6: Thermal transition temperature (° C) of the photosensitive layer
* 7: Fog density fluctuation rate (%)
* 8: Filter supplement
* 9: Hue angle h_ab: Minimum density part
* 10: Hue angle h_ab: D = 1.0 part
As is clear from Table 3, the silver salt photothermographic dry imaging material of the present invention has high sensitivity compared to the comparative example, low fog, excellent image storability after development processing and storage over time, and from the film. It can be seen that there are very few sublimates. The sample of the present invention also has a hue angle value defined by JIS Z8729 that exceeds 180 ° and less than 270 °, has a cold image tone, and can provide an appropriate output image as a diagnostic image. I understood.
[0226]
Example 3
<< Preparation of Silver Salt Photothermographic Dry Imaging Material Sample 301 >>
Using a known extrusion type coater, 301 was prepared by simultaneously applying a total of 3 layers of 2 photosensitive layers and 1 protective layer. For coating, the silver coating amount of the photosensitive layer (upper layer) is 0.9 g / m.²The coated silver amount of the photosensitive layer (lower layer) is 0.6 g / m²The surface protective layer was formed so as to have a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 50 ° C. and a dew point temperature of 10 ° C.
[0227]
Samples 302 to 308 were prepared in the same manner as 301 except that the photosensitive emulsion dispersion, the type of reducing agent, and the binder of the photosensitive layer in the photosensitive layer coating solution were changed to those described in Table 4.
[0228]
Exposure, development processing and various evaluations were performed in the same manner as in Example 1.
[0229]
[Table 4]

[0230]
* 1: Photosensitive emulsion dispersion
* 2: Photosensitive layer binder
* 3: Reducing agent type
* 4: Fog density fluctuation rate (%)
* 5: Filter supplement
* 6: Hue angle h_ab: Minimum density part
* 7: Hue angle h_ab: D = 1.0 part
As is apparent from Table 4, the silver salt photothermographic dry imaging material of the present invention is more sensitive than the comparative example even in the photosensitive layer multi-layer system, but has low fog, and is excellent in image storability and aging preservability after development processing. It can be seen that the film is excellent and there are very few sublimates from the film. The sample of the present invention also has a hue angle value defined by JIS Z8729 that exceeds 180 ° and less than 270 °, has a cold image tone, and can provide an appropriate output image as a diagnostic image. I understood.
[0231]
【The invention's effect】
According to the present invention, it is possible to provide a silver salt photothermographic dry imaging material together with its image recording method, which has high sensitivity, low fog, excellent raw storability and storability with time, and very little sublimate from the film. There is a remarkable effect.

Claims (13)

Amount of coated silver in a silver salt photothermographic dry imaging material having a photosensitive emulsion containing aliphatic silver carboxylate grains and photosensitive silver halide grains, a photosensitive layer containing a silver ion reducing agent, a binder and a crosslinking agent 1.0-1.7 g / m ² And 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and at least one of the silver ion reducing agents is represented by the following general formula (S). A silver salt photothermographic dry imaging material characterized by the above.

[In the formula, Z represents a group of atoms necessary to form a 3- to 10-membered non-aromatic ring together with a carbon atom; _x Represents a hydrogen atom or an alkyl group. R ₀ ', R ₀ ″ Represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group; ₀ Represents a substitutable group on the benzene ring, and n and m represent an integer of 0-2. Multiple Q ₀ May be the same or different. ] Amount of coated silver in a silver salt photothermographic dry imaging material having a photosensitive emulsion containing aliphatic silver carboxylate grains and photosensitive silver halide grains, a photosensitive layer containing a silver ion reducing agent, a binder and a crosslinking agent 1.0-1.7 g / m ² And 60 to 99% by mass of the aliphatic carboxylic acid component in the aliphatic carboxylic acid silver salt particles is behenic acid, and the thermal transition point of the photosensitive layer after development at a temperature of 100 to 180 ° C. A silver salt photothermographic dry imaging material, wherein the temperature is 46 to 200 ° C., and at least one of the silver ion reducing agents is represented by the general formula (S). The silver salt photothermographic dry imaging material according to claim 1 or 2, wherein the compound represented by the general formula (S) is represented by the following general formula (T).

[In the formula, Q ₁ Represents a halogen atom, an alkyl group, an aryl group, or a heterocyclic group; ₂ Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, or a heterocyclic group. G represents a nitrogen atom or a carbon atom. When G is a nitrogen atom, ng is 0. When G is a carbon atom, ng is 0 or 1. Z ₂ Represents a group of atoms necessary to form a 3- to 10-membered non-aromatic ring together with a carbon atom and G. R ₀ ', R ₀ ″, Rx, Q ₀ , N, and m have the same meaning as in general formula (S). ] The alkaline solution used at the time of forming the aliphatic carboxylic acid silver salt particles is a mixture of sodium hydroxide and potassium hydroxide, and the ratio thereof is 1:99 to 95: 5. The silver salt photothermographic dry imaging material according to any one of the above. Aliphatic carboxylic acid silver salt particles are a crystal growth inhibitor or component for the particles. The silver salt photothermographic dry imaging material according to any one of claims 1 to 4, which is formed in the presence of a compound that functions as a powder. The silver salt photothermographic dry imaging material according to any one of claims 1 to 5, wherein the binder has a glass transition temperature Tg of 70 to 105 ° C. The silver salt photothermographic dry imaging material according to claim 5, wherein the compound functioning as a crystal growth inhibitor or a dispersant is an alcohol having 10 or less carbon atoms. 6. The silver salt photothermographic dry imaging material according to claim 5, wherein the compound functioning as a crystal growth inhibitor or a dispersant is a branched aliphatic carboxylic acid or an aliphatic unsaturated carboxylic acid. 6. The silver salt photothermographic dry imaging material according to claim 5, wherein the compound functioning as a crystal growth inhibitor or dispersant is gelatin or polyvinyl alcohol. 6. The silver salt photothermographic dry imaging material according to claim 5, wherein the compound functioning as a crystal growth inhibitor or dispersant is a polymer latex. The silver salt photothermographic dry imaging material according to claim 1, comprising a plurality of photosensitive layers. Hue angle after heat development h _ab 180 ° <h _ab The silver salt photothermographic dry imaging material according to any one of claims 1 to 11, which is <270 °. An image recording method, wherein the silver salt photothermographic dry imaging material according to any one of claims 1 to 12 is exposed by a laser beam scanning exposure machine whose scanning laser beam is a vertical multi.