JP4042324B2 - Photothermographic imaging material - Google Patents

Description

【００２３】
【化２】

【００２４】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、１ｍ²当り１×１０^-6〜１０^-1モル、好ましくは１×１０^-5〜１×１０^-2モルである。
【００２５】
（紫外線吸収基と結合したフラーレン化合物）
フラーレン分子に紫外線吸収剤を結合させる方法は、前記のフラーレン分子にイオン性基またはノニオン性基を反応させる方法と同様にフラーレンに水酸基またはカルボキシル基を導入し、紫外線吸収剤を結合させることができる。結合させる紫外線吸収剤は、ベンゾフェノン骨格を有する化合物、ベンゾトリアゾール骨格を有する化合物、シアノビニル骨格を有する化合物の部品を使用するのが好ましく、特にベンゾフェノン骨格およびベンゾトリアゾール骨格が好ましい。紫外線吸収剤と結合したフラーレン化合物は、紫外線吸収基を有するフラーレン化合物として、本発明の光熱写真材料の構成層内に添加され、紫外線を含む蛍光灯を使用した室内での暴露やシャーカステン上の最低濃度の上昇を抑制する。好ましい具体例をＵＶ１からＵＶ５として下記に示す。
【００２６】
【化３】

【００２７】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、１ｍ²当り１×１０^-6〜１０^-1モル、好ましくは１×１０^-5〜１×１０^-2モルである。
【００２８】
（架橋剤を介して結合剤に架橋する基を有するフラーレン化合物）
架橋剤を介して結合剤に架橋する基を有するフラーレン化合物は、活性メチレン基、エポキシ基、ヒドラジン基またはアルキレン水酸基を有する化合物をフラーレン分子に付加または縮合により導入することができる。前記フラーレン化合物は架橋剤により結合剤と結合する。結合剤への結合により、本発明の光熱写真画像形成材料の生産における膜の剥落を防止することができ、汚れによる画像欠陥の原因を解消することができる。あるいは、現像時の熱による蒸散、揮発、融解等による現像装置内の汚れも防止することができる。好ましい具体例を下記に示す。
【００２９】
【化４】

【００３０】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、剥落を防止することができ、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、１ｍ²当り１×１０^-6〜１０^-1モル、好ましくは１×１０^-5〜１×１０^-2モルである。
【００３１】
（架橋性基を有するフラーレン分子を結合剤に架橋させる架橋剤）
本発明に好ましい架橋剤は、イソシアナート基、ビニルスルホニル基またはエポキシ基を有する化合物である。特に好ましい架橋剤はイソシアナート基、ビニルスルホニル基またはエポキシ基を少なくとも２個有する多官能型架橋剤を挙げることができる。好ましい架橋剤を下記（Ｈ１）〜（Ｈ１６）に示す。
【００３２】
（Ｈ１） ヘキサメチレンジイソシアナート
（Ｈ２） ヘキサメチレンジイソシアナートの３量体
（Ｈ３） トリレンジイソシアナート
（Ｈ４） フェニレンジイソシアナート
（Ｈ５） キシリレンジイソシアナート
（Ｈ６） １，３−ビス（イソシアナートメチル）シクロヘキサン
（Ｈ７） テトラメチレンキシリレンジイソシアナート
（Ｈ８） ｍ−イソプロペニル−α，α−ジメチルベンジルイソシアナート
【００３３】
【化５】

【００３４】
上記架橋剤は、水、アルコール類、ケトン類、非極性の有機溶媒類に溶解して添加しても良いし、塗布液中に固形のまま添加してもよい。添加量は、架橋する基と当量が好ましいが１０倍まで増量しても良いし、１０分の１以下まで減量してもよい。少なすぎると架橋反応が進まないし、多すぎると未反応の架橋剤が写真性を劣化させるので好ましくない。
【００３５】
（フラーレン分子と結合した分光増感色素）
本発明に使用するハロゲン化銀は、フラーレン分子に増感色素骨格が結合した分光増感色素で増感することができる。フラーレン分子に増感色素骨格を導入する方法は、上述したフラーレン化合物の合成と同様にすることができる。分光増感色素としてフラーレン分子部分を有しない化合物を併用してもよい。例えば特開昭６３−１５９８４１号、同６０−１４０３３５号、同６３−２３１４３７号、同６３−２５９６５１号、同６３−３０４２４２号、同６３−１５２４５号等の各公報、米国特許第４，６３９，４１４号、同第４，７４０，４５５号、同第４，７４１，９６６号、同第４，７５１，１７５号、同第４，８３５，０９６号等の各明細書に記載された増感色素を使用することができる。フラーレン分子部を有する分光増感色素の好ましい具体例を下記に示す。
【００３６】
【化６】

【００３７】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、銀１モル当り１×１０^-8〜１０^-2モル、好ましくは１×１０^-7〜１×１０^-2モルである。
【００３８】
（フラーレン分子と結合した染料）
本発明の光熱写真画像形成材料は、必要により該光熱写真画像形成材料のハレーション防止用又はハレーション防止用のＡＨ層又はＢＣ層が設けられ、該ＡＨ層又はＢＣ層に用いられる染料としては、フラーレン分子部を有する染料を使用する。フラーレン分子に染料骨格を導入する方法は、上述したフラーレン化合物の合成と同様にすることができる。また、フラーレン分子部を有しない染料を使用しないで通常の染料を使用してもよい。好ましい例として特開平２−２１６１４０号、同７−１３２９５号、同７−１１４３２号、米国特許第５，３８０，６３５号明細書等に記載される染料を挙げることができる。フラーレン分子部を有する染料とフラーレン分子部を有しない染料と併用してもよい。下記にフラーレン分子部を有する染料の好ましい具体例を下記に示す。
【００３９】
【化７】

【００４０】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、１ｍ²当り１×１０^-6〜１０^-1モル、好ましくは１×１０^-6〜１×１０^-2モルである。
【００４１】
（フラーレン分子と結合した色調剤）
本発明の光熱写真画像形成材料は、銀の画像の色を調節する色調剤を含むことが好ましい。色調剤としてはフタラジンあるいはフタラジン誘導体を使用することができるが、フタラジンあるいはフタラジン誘導体にフラーレン分子を結合させたフラーレン化合物を使用することが好ましい。フラーレン分子に色調剤を結合させる方法は、前記同様フラーレン分子部に導入した水酸基やカルボキシル基等の官能基に、色調剤の水酸基、アミノ基、カルボキシル基またはビニル基等と縮合または付加させることによりフラーレン分子と結合した色調剤を合成することができる。好ましいフラーレン分子部を有する具体例を下記に示す。
【００４２】
【化８】

【００４３】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、銀１モル当り１×１０^-8〜１０^-2モル、好ましくは１×１０^-7〜１×１０^-2モルである。
【００４４】
（フラーレン分子にカブリ抑制基を結合させたカブリ抑制剤）
本発明の光熱写真画像形成材料は、カブリ抑制剤を含むことが好ましく、カブリ抑制剤としては、ハロゲン化銀に吸着する基を有する、硫黄原子、窒素原子、酸素原子等のヘテロ原子と呼ばれる原子を含む化合物を使用することができるが、これらのヘテロ原子を含むカブリ抑制性基をフラーレン分子に結合させたフラーレン化合物を使用することが好ましい。フラーレン分子にカブリ抑制基を結合させる方法は、前記同様フラーレン分子部に導入した水酸基やカルボキシル基等の官能基に、カブリ抑制基部の水酸基、アミノ基、カルボキシル基またはビニル基等と縮合または付加させることによりフラーレン分子と結合したカブリ抑制剤を合成することができる。ヘテロ原子を有するカブリ抑制基としては、それぞれハロゲン原子やアルキル基、アルコキシ基、またはフェニル基等の置換基を有してもよい１−フェニル−５−メルカプトテトラゾール、ベンゾトリアゾール、ベンズイミダゾール、インダゾール基、テトラゾール基、トリアジン基、テトラザインデン基、プリン基、イミダゾール基またはトリアゾール基等を挙げることができる。好ましいフラーレン分子部を有する抑制剤の好ましい具体例を下記に示す。
【００４５】
【化９】

【００４６】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、銀１モル当り１×１０^-8〜１０^-2モル、好ましくは１×１０^-7〜１×１０^-2モルである。
【００４７】
（フラーレン分子に耐光性基を結合させた化合物）
本発明の光熱写真画像形成材料は、耐光性向上剤を含むことが好ましく、耐光性向上剤としては、ハロゲンラジカルを放出する基を有する化合物を使用することができるが、これらの耐光性向上基をフラーレン分子に結合させたフラーレン化合物を使用することが好ましい。フラーレン分子に耐光性向上基を結合させる方法は、前記フラーレン化合物同様フラーレン分子部に導入した水酸基やカルボキシル基等の官能基に、耐光性向上基部の水酸基、アミノ基、カルボキシル基またはビニル基等と縮合または付加させることにより合成することができる。ハロゲンラジカルを放出する基としては、ポリハロメタン基が好ましく、特にトリブロモメチル基を芳香族環（ベンゼン環、ナフタレン環等）またはヘテロ原子を有するヘテロ環（ピリジン環、トリアジン環、ピリミジン環、キノリン環、ピリミジン環、フラン環等）に結合した基が好ましく、更にポリハロメチル基と芳香族環基またはヘテロ環基と結合させる連結基は、スルホニル基、スルホンアミド基またはカルボアミド基等の硫黄原子や窒素原子含む基が好ましい。フラーレン分子部を有する耐光性向上剤の好ましい具体例を下記に示す。
【００４８】
【化１０】

【００４９】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、銀１モル当り１×１０^-8〜１０^-2モル、好ましくは１×１０^-7〜１×１０^-2モルである。
【００５０】
（フラーレン分子に不安定なカルコーゲン原子基を有する基を結合させた化学増感剤）
感光性ハロゲン化銀は、フラーレン分子に不安定なカルコーゲン原子基を結合させた増感剤で化学増感される。カルコーゲン原子としては、硫黄、セレンまたはテルル原子が好ましい。またはこれらの増感剤と金化合物、白金化合物、パラジウム化合物と組み合わせによって化学増感することができる。フラーレン分子に不安定なカルコーゲン原子基を結合させる方法は、前記フラーレン分子に水酸基またはカルボキシル基を導入した後、不安定カルコーゲン原子有する化学増感剤の骨格構造を縮合や付加反応で導入することにより合成できる。好ましい具体例を下記に示す。
【００５１】
【化１１】

【００５２】
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。使用量は、銀１モル当り１×１０^-8〜１０^-2モル、好ましくは１×１０^-7〜１×１０^-2モルである。
【００５３】
本発明のフラーレン化合物を合成方法を説明する。先ず代表的中間体４種を合成した。反応スキームを下記に示す。
【００５４】
【化１２】

【００５５】
【化１３】

【００５６】
中間体１（ｃｐｄ−１）の合成
攪拌機、温度計、吹込管を備えた４ツ口フラスコに、窒素雰囲気下、乾燥トルエン９６０ｍｌにフラーレン（Ｃ₆₀）２．０ｇ（２．７６ｍｍｏｌ）およびテトラブチルアンモニウムアイオダイド１．６７ｇ（４．５ｍｍｏｌ）を溶解させ、１，２−ジブロモメチル−４，５−ジメトキシベンゼンを１．３４ｇ（４．２ｍｍｏｌ）仕込み、遮光下に１０時間還流を行った。室温まで放冷し、水で洗ったあとトルエン：ヘキサンが３：１の溶媒でシリカゲルクロマトグラフィーで精製した。この化合物の１２４ｍｇ（０．１４ｍｍｏｌ）を乾燥トルエン溶液に０℃に保ちながら３臭化硼素を０．８ｍｌ（９．２ｍｌ）加えて１２時間反応させた。反応後未反応の３臭化硼素を冷水で消失させ酢酸エチルで抽出し、硫酸マグネシウムで乾燥させた。精製物をＴＨＦ／ヘキサンで再沈殿させ精製した。
【００５７】
中間体２（ｃｐｄ−２）の合成
攪拌機、温度計、吹込管を備えた４ツ口フラスコに、窒素雰囲気下、乾燥トルエン９６０ｍｌにフラーレン（Ｃ₆₀）２．０ｇ（２．７６ｍｍｏｌ）およびテトラブチルアンモニウムアイオダイド１．６７ｇ（４．５ｍｍｏｌ）を溶解させ、１，２−ジブロモメチル−４−メトキシベンゼンを１．１２ｇ（４．２ｍｍｏｌ）仕込み、遮光下に１２時間還流を行った。室温まで放冷し、水で洗ったあとトルエン：ヘキサンが３：１の溶媒でシリカゲルクロマトグラフィーで精製した。この化合物の１０４ｍｇ（０．１４ｍｍｏｌ）を乾燥トルエン溶液に０℃に保ちながら３臭化硼素を０．８ｍｌ（９．２ｍｌ）加えて１２時間反応させた。反応後未反応の３臭化硼素を冷水で消失させ酢酸エチルで抽出し、硫酸マグネシウムで乾燥させた。精製物をＴＨＦ／ヘキサンで再沈殿させ精製した。
【００５８】
中間体３（ｃｐｄ−３）の合成
攪拌機、温度計、吹込管を備えた４ツ口フラスコに、窒素雰囲気下、乾燥トルエン９８０ｍｌにフラーレン（Ｃ₆₀）２．０ｇ（２．７６ｍｍｏｌ）およびテトラブチルアンモニウムアイオダイド１．６７ｇ（４．５ｍｍｏｌ）を溶解させ、１，２−ジブロモメチル−４−カルボキシメチルベンゼンを１．２４ｇ（４．２ｍｍｏｌ）仕込み、遮光下に２１時間還流を行った。室温まで放冷し、水で洗ったあとトルエン：ヘキサンが３：１の溶媒でシリカゲルクロマトグラフィーで精製した。この化合物の１２８ｍｇ（０．１４ｍｍｏｌ）を乾燥トルエン溶液に０℃に保ちながら３臭化硼素を０．８ｍｌ（９．２ｍｌ）加えて１２時間反応させた。反応後未反応の３臭化硼素を冷水で消失させ酢酸エチルで抽出し、硫酸マグネシウムで乾燥させた。精製物をＴＨＦ／ヘキサンで再沈殿させ精製した。
【００５９】
中間体４（ｃｐｄ−４）の合成
攪拌機、温度計、吹込管を備えた４ツ口フラスコに、窒素雰囲気下、乾燥トルエン９３０ｍｌにフラーレン（Ｃ₆₀）２．０ｇ（２．７６ｍｍｏｌ）およびテトラブチルアンモニウムアイオダイド１．６７ｇ（４．５ｍｍｏｌ）を溶解させ、１，４−ジブロモ−２−カルボキシメチル−２，３−ブチレンを１．２４ｇ（４．２ｍｍｏｌ）仕込み、遮光下に２１時間還流を行った。室温まで放冷し、水で洗ったあとトルエン：ヘキサンが３：１の溶媒でシリカゲルクロマトグラフィーで精製した。この化合物の１０８ｍｇ（０．１４ｍｍｏｌ）を乾燥トルエン溶液に０℃に保ちながら３臭化硼素を０．８ｍｌ（９．２ｍｌ）加えて１２時間反応させた。反応後未反応の３臭化硼素を冷水で消失させ酢酸エチルで抽出し、硫酸マグネシウムで乾燥させた。精製物をＴＨＦ／ヘキサンで再沈殿させ精製した。
【００６０】
Ｓ１の合成
窒素置換した１Ｌのオートクレーブに中間体１（ｃｐｄ−１）を２．２ｇおよびポリエチレングリコール２．３ｇ（分子量８９８）を導入して濃硫酸を０．２ｇ滴下して５８℃で１時間反応させた後、反応混合物をトルエン２Ｌに投入し、得られた固体を濾取し窒素気流下室温で乾燥させ、粉末状固体を得た。以下同様にしてＳ２〜Ｓ５を合成した。
【００６１】
ＡＳ２の合成
窒素置換した１Ｌのオートクレーブに中間体２（ｃｐｄ−２）を２．１ｇおよびポリエチレングリコール２．２ｇ（分子量８９８）を導入して濃硫酸を０．２ｇ滴下して７８℃で１時間反応させた後、反応混合物をトルエン２Ｌに投入し、得られた固体を濾取し窒素気流下室温で乾燥させ、粉末状固体を得た。以下同様にしてＡＳ１、ＡＳ３〜ＡＳ５を合成した。
【００６２】
ＵＶ１の合成
窒素置換した１Ｌのオートクレーブに中間体４（ｃｐｄ−４）を２．２ｇおよび２−（２−ヒドロキシ−５−ヒドロキシエチルフェニル）ベンゾトリアゾール０．３ｇを導入して濃硫酸を０．２ｇ滴下して７８℃で１時間反応させた後、反応混合物をトルエン２Ｌに投入し、得られた固体を濾取し窒素気流下室温で乾燥させ、粉末状固体を得た。以下同様にしてＵＶ２〜ＵＶ５を合成した。
【００６３】
ＬＰ１の合成
窒素置換した１Ｌのオートクレーブに中間体４（ｃｐｄ−４）を２．２ｇ（２．３ｍｍｏｌ）および４−アミノ−４−メチル−２−ペンタノン２．６５ｇ（２．３ｍｍｏｌ）を導入して濃硫酸を０．２ｇ滴下して６８℃で１時間反応させた後、反応混合物をトルエン２Ｌに投入し、得られた固体を濾取し窒素気流下室温で乾燥させ、粉末状固体を得た。以下同様にして中間体にエポクロルヒドリン、ｐ−アミノフェニルヒドラジン、ヒドロキシエトキシエチルアルコールおよびエチレンジアミンを中間体４に反応させてＬＰ２〜ＬＰ５を合成した。
【００６４】
ＤＥ１〜ＤＥ３およびＤＳ１〜ＤＳ３の合成
前記ＡＳ１と同様にして中間体２にヘプタメチンシアニン色素を反応させてＤＥ１〜ＤＥ３およびＤＳ１〜ＤＳ３を得た。
【００６５】
ＡＦ１の合成
前記ＬＰ１の合成と同様に中間体４に１−（ｐ−ヒドロキシフェニル）−５−メルカプト−テトラゾールを反応させてＡＦ１を得た。５−ヒドロキシベンゾトリアゾール、５−ヒドロキシベンズイミダゾール、５−アミノインダゾール等を反応させてＡＦ２〜ＡＦ４を合成した。ＡＦ５は、３，４−ジメチルチオベンゾイルクロリドを反応させ、加水分解して合成した。
【００６６】
ＴＮ１の合成
前記ＡＦ１と同様に合成したが、ここでは５−ヒドロキシ−アジリジンを反応させた。同様にしてＴＮ２からＴＮ５を得た。
【００６７】
ＨＬ１の合成
前記Ｓ１の合成と同様にして中間体１に１−カルボキシ−４−トリブロモメチルベンゼンを反応させた。同様にしてＨＬ２〜ＨＬ５を得た。
【００６８】
ＳＴ１〜ＳＴ５の合成
前記ＬＰ１の合成と同様にしたが、ここでは中間体４にチオウレアを反応させた。以下セレノウレア、ｐ−アミノテルルウレア、ｐ−アミノセレノウレアおよびｐ−アミノ−パーフロロフェニルセレノウレアを反応させて合成した。
【００６９】
（有機銀塩）
本発明の光熱写真画像形成材料に含有される有機銀塩は還元可能な銀源であり、還元可能な銀イオン源を含有する有機酸、ヘテロ有機酸及び酸ポリマーの銀塩などが用いられる。また、配位子が、４．０〜１０．０の銀イオンに対する総安定定数を有する有機又は無機の銀塩錯体も有用である。銀塩の例は、Ｒｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ第１７０２９及び２９９６３に記載されており、次のものがある：有機酸の塩（例えば、没食子酸、シュウ酸、ベヘン酸、ステアリン酸、パルミチン酸、ラウリン酸等の塩）等。有機銀の使用量は、ハロゲン化銀１モル当たり１０分の１モルから１００モルが好ましい。
【００７０】
（還元剤）
本発明の光熱写真画像形成材料に含有される好ましい還元剤の例は、米国特許第３，７７０，４４８号、同３，７７３，５１２号、同３，５９３，８６３号等の各明細書、及びＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ第１７０２９及び２９９６３に記載されており、次のものが挙げられる。
【００７１】
Ｋ１：１，１−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
Ｋ２：ビス（２−ヒドロキシ−３−ｔ−ブチル−５−メチルフェニル）メタン
Ｋ３：２，２−ビス（４−ヒドロキシ−３−メチルフェニル）プロパン
Ｋ４：４，４−エチリデン−ビス（２−ｔ−ブチル−６−メチルフェノール）
Ｋ５：２，２−ビス（３，５−ジメチル−４−ヒドロキシフェニル）プロパン
前記に示される化合物は、水に分散したり、有機溶媒に溶解して使用する。有機溶媒は、メタノールやエタノール等のアルコール類やアセトンやメチルエチルケトン等のケトン類、トルエンやキシレン等の芳香族系を任意に選択することができる。還元剤の使用量は、銀１モル当り１×１０^-2〜１０モル、好ましくは１×１０^-2〜３モルである。
【００７２】
（感光性ハロゲン化銀粒子）
本発明の光熱写真画像形成材料の感光層中に含有される感光性ハロゲン化銀は、シングルジェット若しくはダブルジェット法などの写真技術の分野で公知の任意の方法により、例えばアンモニア法乳剤、中性法、酸性法等のいずれかの方法で予め調製し、次いで本発明の他の成分と混合して本発明に用いる組成物中に導入することができる。この場合に感光性ハロゲン化銀と有機銀塩の接触を充分に行わせるため、例えば感光性ハロゲン化銀を調製するときの保護ポリマーとして米国特許第３，７０６，５６４号、同第３，７０６，５６５号、同第３，７１３，８３３号、同第３，７４８，１４３号、英国特許第１，３６２，９７０号各明細書に記載されたポリビニルアセタール類などのゼラチン以外のポリマーを用いる手段や、英国特許第１，３５４，１８６号明細書に記載されているような感光性ハロゲン化銀乳剤のゼラチンを酵素分解する手段、又は米国特許第４，０７６，５３９号明細書に記載されているように感光性ハロゲン化銀粒子を界面活性剤の存在下で調製することによって保護ポリマーの使用を省略する手段等の各手段を適用することができる。
【００７３】
感光性ハロゲン化銀は、画像形成後の白濁を低く抑えるために、また良好な画質を得るために粒子サイズが小さいものが好ましい。平均粒子サイズで０．１μｍ以下、好ましくは０．０１〜０．１μｍ、特に０．０２〜０．０８μｍが好ましい。又、ハロゲン化銀の形状としては特に制限はなく、立方体、八面体の所謂正常晶や正常晶でない球状、棒状、平板状等の粒子がある。又ハロゲン化銀組成としても特に制限はなく、塩化銀、塩臭化銀、塩沃臭化銀、臭化銀、沃臭化銀、沃化銀のいずれであってもよい。
【００７４】
上記ハロゲン化銀の量はハロゲン化銀及び後述の有機銀塩の総量に対し５０質量％以下、好ましくは２５〜０．１質量％、更に好ましくは１５〜０．１質量％の間である。上記のハロゲン化銀形成成分を用いて有機銀塩の一部をハロゲン化銀に変換させる工程の反応温度、反応時間、反応圧力等の諸条件は作製の目的にあわせ適宜設定することができるが、通常、反応温度は−２３℃乃至７４℃、その反応時間は０．１秒乃至７２時間であり、その反応圧力は大気圧に設定されるのが好ましい。
【００７５】
（結合剤）
本発明の光熱写真画像形成材料の感光層又は非感光層に用いられる高分子結合剤としては、ポリビニルブチラール、ポリアクリルアミド、ポリスチレン、ポリ酢酸ビニル、ポリウレタン、ポリアクリル酸エステル、スチレン−ブタジエン共重合体、アクリロニトリル−ブタジエン共重合体、塩化ビニル−酢酸ビニル共重合体、スチレン−ブタジエン−アクリル共重合体などが挙げられる。更に乾燥後、膜を形成したのち、その塗膜の平衡含水率の低いものが好ましく、特に含水率の低いものとして、例えば、有機溶媒系の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およびポリアセタールを挙げることができる。ポリアセタールは、ポリ酢酸ビニルを鹸化することによりポリビニルアルコールを製造し、このポリビニルアルコールをアルデヒド化合物で反応させて得られるポリマーを意味するが、本発明に好ましいポリアセタールは、ブチルアルデヒドでアセタール化をしたポリブチラール、アセトアルデヒドでアセタール化したポリアセタール（狭義でのポリアセタール）が好ましい。アセタール化は、１％〜１００％まで理論的には存在するが、実用的には２０％〜９５％が好ましい。アセタール化度が低いと水酸基が多くなり、写真性能において湿度に弱い特性を示し、アセタール化度が高いと反応温度や時間が過酷になり、コストや生産性が低下する。水系塗布用には、水分散系ポリマーのスチレンとブタジエンの共重合体、スチレンとアクリル酸アルキルエステルまたはメタクリル酸アルキルエステル類の共重合体、アクリル酸アルキルエステル類とメタクリル酸アルキルエステルの共重合体を挙げることができる。また、上記水分散系ポリマーとしては、平均粒子径が１ｎｍから数μｍの範囲の微粒子にして水系分散媒中に分散されたものが好ましい。水分散系ポリマーは水系塗布の結合剤として広く使用されている中で耐水性を向上させることができる点から疎水性であることが特に好ましい。ポリマーの重合度は、１０程度から１万程度まで自由に選択することができるが、１００〜６０００が塗布性や合成するときの生産性から好ましい。
【００７６】
（支持体）
支持体としては、ポリエチレンテレフタレート、ポリエチレンナフタレートまたはシンジオタクチックポリスチレン等の支持体が好ましく、２軸延伸や熱固定した光学的に等方性が高く、寸法安定性のよい５０μｍ〜４００μｍ厚のものがよい。
【００７７】
〈画像露光〉
露光方法としては、特開平９−３０４８６９号明細書、同９−３１１４０３号および特開２０００−１０２３０号明細書記載の方法によりレーザー露光することができる。本発明の光熱写真画像形成材料の露光は、当該感材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、当該感材を赤外光に感じ得るものとした場合は、赤外光域ならば如何なる光源にも適用可能であるが、レーザーパワーがハイパワーである事や、感光材料を透明にできる等の点から、赤外半導体レーザー（７８０ｎｍ、８２０ｎｍ）がより好ましく用いられる。
【００７８】
〈熱現像装置〉
光熱写真画像形成材料を現像する装置は、特開平１１−６５０６７号、同１１−７２８９７号および同１１−８４６１９号明細書記載の装置を使用することができる。
【００７９】
【実施例】
以下、本発明の実施例を説明するが、本発明の実施の態様はこれらにより限定れない。
【００８０】
実施例１
（光熱写真画像形成材料の作製）
〈下引済み支持体の作製〉
厚さ１７５μｍのポリエチレンテレフタレート支持体の両面に１２Ｗ／ｍ²・分のコロナ放電処理を施し、一方の面に下記下引塗布液ａ−１を乾燥膜厚０．６μｍになるように塗設し乾燥させて下引層Ａ−１を設け、また反対側の面に下記下引塗布液ｂ−１を乾燥膜厚０．６μｍになるように塗設し乾燥させて下引層Ｂ−１を設けた。
【００８１】
《下引塗布液ａ−１》
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％）
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％）を１５倍に希釈する。
【００８２】
《下引塗布液ｂ−１》
ブチルアクリレート（４０質量％）
スチレン（２０質量％）
グリシジルアクリレート（４０質量％）
の共重合体ラテックス液（固形分３０％）を１５倍に希釈する。
【００８３】
引き続き、下引層Ａ−１及び下引層Ｂ−１の上表面に、１２Ｗ／ｍ²・分のコロナ放電を施し、下引層Ａ−１の上には、下記下引上層塗布液ａ−２を塗布乾燥して下引上層Ａ−２（感光層側用）を設け、下引層Ｂ−１の上には下記下引上層塗布液ｂ−２を塗布乾燥して帯電防止機能をもつ下引上層Ｂ−２（ＢＣ層用）を設けた。
【００８４】
《下引上層塗布液ａ−２》
スチレンとブタジエンの１：２共重合体 ０．４ｇ／ｍ²
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％）
２−ヒドロキシエチルアクリレート（２０質量％）
メタクリル酸（５質量％）
の共重合体ラテックス液（固形分３０％） ０．３ｇ／ｍ²
《下引上層塗布液ｂ−２》
スチレンとブタジエンの１：２共重合体 ０．４ｇ／ｍ²
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％）
２−ヒドロキシエチルアクリレート（２０質量％）
メタクリル酸（５質量％）
の共重合体ラテックス液（固形分３０％） ０．３ｇ／ｍ²
上記作製した下塗り支持体の上に下記組成のＡＨ層、感光層、感光層保護層を同時重層塗布した。感光層に先立ちＢＣ層とＢＣ層保護層を予め同時重層したが、この逆順序でもよく、また、感光層とＢＣ層側を同時重層してもよい。
【００８５】
先ず、塗布に先立ちハロゲン化銀を調製し、次いで作製したハロゲン化銀を使用して有機銀塩を調製した。
【００８６】
〈ハロゲン化銀粒子乳剤Ａの調製〉
水９００ｍｌ中にイナートゼラチン７．５ｇ及び臭化カリウム１０ｍｇを溶解して温度２８℃、ｐＨを３．０に合わせた後、硝酸銀７４ｇを含む水溶液３７０ｍｌと（９８／２）のモル比の臭化カリウムと沃化カリウムを０．４３６モル含む水溶液３７０ｍｌを、ｐＡｇ７．７に保ちながらコントロールドダブルジェット法で１０分間かけて添加した。硝酸銀の添加と同期してヘキサクロロイリジウムのナトリウム塩を１×１０^-6モル／銀１モル添加した。その後４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデン０．３ｇを添加しＮａＯＨでｐＨを５に調整して平均粒子サイズ０．０３６μｍ、投影直径面積の変動係数８％、〔１００〕面比率８７％の立方体沃臭化銀粒子を得た。この乳剤にゼラチン凝集剤を用いて凝集沈降させ脱塩処理後、水を加えて１６０ｍｌに仕上げた。
【００８７】
〈水分散有機銀塩の調製〉
３９８０ｍｌの純水にベヘン酸１１１．４ｇ、アラキジン酸８３．８ｇ、ステアリン酸５４．９ｇを８０℃で溶解した。次に高速で攪拌しながら１．５モル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℃に冷却して有機酸ナトリウム溶液を得た。上記の有機酸ナトリウム溶液の温度を５５℃に保ったまま、前記ハロゲン化銀粒子乳剤Ａ（銀０．０３８モルを含む）と純水４２０ｍｌを添加し５分間攪拌した。次に１モルの硝酸銀溶液７６０．６ｍｌを２分間かけて添加し、さらに２０分攪拌し、濾過により水溶性塩類を除去した。その後、濾液の電導度が２μＳ／ｃｍになるまで脱イオン水による水洗、濾過を繰り返し、最後に円心脱水後乾燥した。
【００８８】
〈感光層及びＢＣ層の塗布〉
前記下引層を施した支持体上に以下の感光層側およびＢＣ側の各層を塗布した。尚、乾燥は感光層側およびＢＣ側とも各々４５℃、１分間で行った。
【００８９】
（ＢＣ層側塗布）
バック面側には以下の組成物を調製した塗布液を以下の付き量なるように同時重層塗布乾燥してＢＣ層を形成した。
【００９０】
《ＢＣ層塗布》
結合剤：ＰＶＢ−１ １．８ｇ／ｍ²
ヘキサメチレンジイソシアナート １×１０^-4モル／ｍ²
染料：Ｃ１ ２．２×１０^-5モル／ｍ²
《ＢＣ保護層の塗布》
セルロースアセテートブチレート １．１ｇ／ｍ²
ヘキサメチレンジイソシアナート １×１０^-4モル／ｍ²
（感光層側の塗布）
《ＡＨ層の塗布》
結合剤：ＰＶＢ−１ ０．４ｇ／ｍ²
染料：Ｃ１ １．３×１０^-5モル／ｍ²
《感光層の塗布》
感光層形成のため以下の組成物の塗布液を調製し、以下の付き量になるように塗布乾燥した。銀量として１．３６ｇ／ｍ²になる量の前記有機銀塩の調製液をポリマー結合剤と混合した。
【００９１】

【００９２】
【化１４】

【００９３】
《表面保護層》
以下の組成物を加えて調製した塗布液を、以下の付き量になるように感光層上に塗布乾燥して表面保護層を形成した。
【００９４】

ＰＶＢ−１は、重合度５００のポリ酢酸ビニルを９８％鹸化後、残存水酸基の８６％をブチラール化して使用した。ＰＶＢ−１はＢＣ層の結合剤としても使用した。尚、イオン性化合物の比較としてラウリルアルコールのスルホン酸エステルをｒｅｆ−１の化合物として、ノニオン性の化合物としてステアリン酸と重合度２０のポリエチレングリコールのエステル化合物をｒｅｆ−２とした。
【００９５】
（写真性能の評価）
上記作製した試料を２５℃で４８％相対湿度の雰囲気下に、８１０ｎｍの半導体レーザー露光用の感光計で露光し、露光後１２０℃で８秒間加熱後、得られた試料のカブリと感度を求めた。感度はカブリ＋濃度０．３を与える露光量の逆数から算出し、試料番号の最初の相対感度を１００とした。
【００９６】
（塗布性の評価）
重層塗布試験機でＡＨ層、感光層および保護層を同時重層塗布した巾５０ｃｍ長さ１ｍの試料を濃度１．０±０．１になるように均一ベタ露光を行い現像処理をし、塗布性を評価した。現像ムラと塗布ムラが区別できるように現像方向と塗布方向が同一にならないように９０℃方向をずらして現像処理した。塗布性は試料内に１０００個の濃度測定を行い濃度の標準偏差を平均濃度で割り１００を掛けた数字を算出し、塗布の均一性として評価した。標準偏差５０以上のレベルを１、以下標準偏差３０〜５０のレベルを２、標準偏差２０〜３０のレベルを３、標準偏差１５〜２０のレベルを４、標準偏差１５以下のレベルを５とした。実用的に問題ないレベルは３である。実験結果を表１に示す。尚、塗布の溶媒としてメチルエチルケトンを使用し、固形分濃度を３２％として塗布液を調製した。
【００９７】
（帯電防止性能）
塗布された５ｃｍ×１５ｃｍの試料を、相対湿度２０％の部屋内に１０時間放置したのち、ナイロン布で表面を５回摩擦し、直径２ｍｍの発泡スチレンビーズを近づけて吸着する程度を評価した。最も多く付着するレベルを１、殆ど付着しないレベルを５とし、実用的に問題ないレベルを３とした。実験内容および実験結果を表１に示す。
【００９８】
【表１】

【００９９】
表１より本発明のイオン性またはアニオン性のフラーレン化合物を使用すると写真性能に悪影響を与えることなく、塗布性を向上させ、帯電防止効果を上げることがわかる。
【０１００】
実施例２
実施例１と同様に実験したが、イオン性またはノニオン性化合物の代わりにここでは紫外線吸収剤を添加し、写真性能および耐光性を評価した。耐光性試験は、紫外線蛍光灯（松下電工社製蛍光管ＦＬ４０ＳＤ）４０ワットを２本並列に並べ２ｍ直下に現像済み試料を放置し、未露光部の濃度上昇を測定した。
【０１０１】
尚、比較の紫外線吸収剤は、ベンゾフェノンをｒｅｆ−３とし、２−（２−ヒドロキシ−５−エチルフェニル）ベンゾトリアゾールをｒｅｆ−４として表記した。また、感光層に添加する実験を合わせて行った。面積当たり添加量は、同一とした。実験内容および実験結果を表２に示す。
【０１０２】
【表２】

【０１０３】
表２より本発明の紫外線吸収基を有するフラーレン化合物は、写真性能を劣化させず耐光性を向上させることがわかる。
【０１０４】
実施例３
実施例１と同様に試料を作製したが、ここではフラーレン化合物として「架橋剤を介して結合する基」をフラーレン分子に結合させた化合物を使用し、同時に架橋剤を使用して剥落耐性を評価した。剥落特性は２０本の対向ローラーを並べた搬送性試験機で３００ｍ／分の早さで試験試料を３０分間搬送し、搬送ローラーの表面に付着した汚れを評価した。２００倍のルーペで観察し、最もよごれているレベルを１、よごれのないレベルを５、よごれが有っても実用的に問題のないレベルを３として評価した。結果を表３に示した。
【０１０５】
【表３】

【０１０６】
表３より本発明の架橋剤を介して結合する基をフラーレン分子に結合させた化合物を使用すると高速搬送においてローラーの汚れを抑えることがわかる。
【０１０７】
実施例４
実施例１と同様に試験試料を作製したが、ここではフラーレン分子に不安定なカルコーゲン基を結合させた化学増感剤をハロゲン化銀の化学熟成に使用した。化学熟成はハロゲン化銀の脱塩後の粒子に対してハロゲン化銀１モルに対して１０^-6モル添加して５５℃１時間化学熟成を行った。尚、ここでは、実施例１で保護膜に添加したフラーレン化合物は使用しないで試料を作製した。尚、化学増感剤の比較として、ジフェニルチオ尿素（ＤＰＴＵ）を使用した。実験内容と結果を下記表４に示す。
【０１０８】
【表４】

【０１０９】
表４より本発明のフラーレン分子に不安定なカルコーゲン基を結合させた化学増感剤で増感を行うとカブリが高くならず、高感度であることがわかる。
【０１１０】
実施例５
実施例１と同様に試料を作製したが、試料５０２〜５０８は感光層に実施例１で使用した分光増感色素（ｒｅｆ−５）に代えて、表５の添加剤１に示す本発明の分光増感色素をハロゲン化銀１モル当たり３×１０^-5モル添加した。尚、ｒｅｆ−５を添加剤２として、試料５０６〜５０８ではハロゲン化銀１モル当たり３×１０^-5モル添加した。保護層にはフラーレン化合物は添加せずに行った。写真性能として、カブリ、感度および鮮鋭性を評価した。鮮鋭性の評価はＭＴＦ（Ｍｏｄｕｌａｔｉｏｎ Ｔｒａｎｓｆｅｒ Ｆｕｎｃｔｉｏｎ）チャートを使用して変調伝達度を求めた。実験内容と実験結果を表５に示す。
【０１１１】
【表５】

【０１１２】
表５より本発明の増感色素を使用すると感度、鮮鋭性が高くなることがわかる。また、分光増感色素と併用すると鮮鋭性が向上することがわかる。
【０１１３】
実施例６
実施例１と同様に試料を作製したが、ここでは、ＢＣに使用した染料の代わりに本発明の分光増感色素をハレーション防止染料として使用した。現像後、実施例５と同様に変調伝達度を測定し鮮鋭性の評価とした。実験内容および得られた結果を表６に示す。
【０１１４】
【表６】

【０１１５】
表６よりハレーション防止染料として使用すると鮮鋭性が向上することがわかる。
【０１１６】
実施例７
実施例１と同様に試料を作製したが、ここでは、保護層に添加したフラーレン化合物を除き、感光層にフラーレン分子にカブリ抑制基を結合させてカブリ防止剤として使用した。尚、カブリ抑制剤の比較として、１−フェニル−５−メルカプトテトラゾール（ＰＭＴ）を使用し、添加量はハロゲン化銀１モル当たり６×１０^-5モルとした。実験内容と実験結果を下記表７に示す。
【０１１７】
【表７】

【０１１８】
表７よりフラーレン分子部にカブリ抑制基が結合したフラーレン化合物を使用するとカブリ抑制性があることがわかる。
【０１１９】
実施例８
実施例７と同様に実験したが、感光層に添加したフラーレン化合物はポリハロメタン基をフラーレン分子部に結合させたフラーレン化合物である。添加量は銀１モル当たり２．４×１０^-4モルであった。比較の化合物としてトリブロモメチルスルホニルベンゼン（ｒｅｆ−６）を使用した。耐光性試験は、４０ワットの蛍光管が４本装着されたシャーカステンに試料を１０時間放置し、そのときのカブリを評価した。
【０１２０】
【表８】

【０１２１】
表８より本発明のフラーレン分子部にポリハロメタン基を結合させた化合物を使用するとカブリの値が増加しないことがわかる。
【０１２２】
実施例９
実施例８と同様に実験したが、ここでは感光層に添加したフラーレン化合物として、フラーレン分子部に茶色銀色調を黒銀色調にする色調基を結合させたフラーレン化合物を添加した。色調の評価は、最も濃い茶色を１ランクとし、最も黒色を５ランクと評価した。実用的に問題ないレベルの色調を３とした。尚、比較としてフタラジン（ｒｅｆ−７）を使用した。実験結果を下記表９に示す。
【０１２３】
【表９】

【０１２４】
表９より本発明のフラーレン分子部に黒色色調化基を結合させたフラーレン化合物は色調が改良されていることがわかる。
【０１２５】
【発明の効果】
本発明により、感度、カブリ抑制、保存性、鮮鋭性、増感、色調、画像欠陥等の諸性能を向上した光熱写真画像形成材料を得た。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photothermographic image forming material that forms an image by thermal development after exposure, and relates to sensitivity, fog suppression, storage stability, sharpness, and sensitization using a compound in which a photographically useful group is bonded to a fullerene molecule. The present invention relates to a technique for improving various performances such as color tone and image defects.
[0002]
[Prior art]
In recent years, there has been a strong demand for photographic materials that form images by light or heat treatment that does not generate waste liquid from wet processing in terms of environmental protection and workability in the medical field, especially by developing using both light and heat, A technology relating to a photothermographic image forming material for photographic technology capable of forming a clear black image with high resolution has been commercialized and rapidly spread. Since these photographic materials are usually developed at a temperature of 80 ° C. or higher, they are called photothermographic image forming materials as distinguished from conventional wet photosensitive materials that are liquid-developed in the range of 25 ° C. to 45 ° C.
[0003]
In this type of photothermographic image forming material, since the developer is contained in the photosensitive layer, the sensitivity and fog are likely to fluctuate during storage, and the light fogging caused by the photosensitive silver halide in the unexposed area after development is reduced. The increase is a problem. In order to solve these problems, the form of silver halide is different, and various photographic additives suitable for this form are used. As the silver halide, ultrafine silver iodobromide or silver chlorobromide having an average grain size of 10 nm to 60 nm and a monodispersity of 5 to 60 is used, and a chemical sensitizer having a higher sensitizing ability than a normal sensitizer. And spectral sensitizing dyes have been used. As a dye for preventing halation and irradiation, UV absorbers and dyes with high visible light transmittance after development are used, and a color tone that makes the color of silver after development black, and unexposed silver halide after development Light resistance improvers and the like that suppress light fogging are used. As the light fastness improver, polyhalomethane compounds that release halogen radicals are generally used. In addition, the additive, such as an antistatic agent that suppresses the generation of static electricity when a coated film that has been applied and dried is transported by a roller, in order to apply the constituent layers including the photosensitive layer uniformly at the same time, There is a need for further improvement in photographic performance. However, satisfactory performance was not obtained. The antistatic agent is an item related to photographic performance because it suppresses the generation of static electricity, prevents dust adhesion and discharge fogging caused by the static electricity, and prevents image defects. Further, the application uniformity of the activator or the like is also an item included in the photographic performance because it is related to the unevenness of the image after development.
[0004]
On the other hand, fullerene compounds composed of 60, 70, 72, 76, 78, 82, and 84 carbon atoms are synthesized, and application development in the field of electronic materials is being studied. JP-A-6-242543 describes the use of fullerene compounds as chemical sensitizers in silver halide photographic light-sensitive materials. Here, the fullerene compound which consists only of carbon atoms is made into object, and the sensitization property only of the fullerene of carbon 60 is only evaluated in the Example. Although there is a description “fullerene compound or derivative thereof”, the structure of the derivative is not shown, and a compound bonded to an organic group is not suggested. Techniques using fullerene as an image forming material are disclosed in JP-A-6-018136, JP-A-6-169812, JP-A-7-33751, JP-A-7-64310, JP-A-7-181698, and JP-A-9-152726. Although it is not a photothermographic image-forming material containing silver halide and organic silver, it is not the fullerene compound of the present invention. The present invention has been achieved as a result of earnest research to improve various performances that have been conventionally required by coupling a photographically useful group to fullerene.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to improve the photographic performance of a photothermographic image-forming material with a compound in which a photographically useful group is bonded to a fullerene molecule. The photographic performance here is suppression of fogging, high sensitivity, sharpness, raw storability, image storability, color tone, coating property, and the like.
[0006]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions.
[0007]
1. A photothermographic image forming material having at least one photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support provided with an undercoat layer. A photothermographic image-forming material comprising a compound having a photographically useful group bonded to a fullerene molecule in at least one of the layers.
[0008]
2. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is an ionic group or a nonionic group bonded to a cyclic or non-cyclic hydrocarbon group.
[0009]
3. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is an ultraviolet absorbing group.
[0010]
4). 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is a group bonded to a binder via a crosslinking agent.
[0011]
5. 5. The photothermographic image-forming material as described in 4 above, wherein the group bonded to the binder via a crosslinking agent is an active methylene group, an epoxy group, a hydrazine group or a hydroxyl group.
[0012]
6). 6. The photothermographic image forming material as described in 4 or 5 above, wherein the crosslinking agent has an isocyanate group, a vinylsulfonyl group or an epoxy group.
[0013]
7. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is a spectral sensitizing dye group.
[0014]
8). 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is an irradiation or antihalation dye group.
[0015]
9. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is a fog suppressing group.
[0016]
10. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is a light fastness improver group.
[0017]
11. 2. The photothermographic image-forming material as described in 1 above, wherein the photographically useful group is a color toner.
[0018]
12 In a photothermographic image-forming material having at least one photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support, the photosensitive silver halide grains are unstable to fullerene molecules. A photothermographic image-forming material which is chemically sensitized with a chemical sensitizer to which a chalcogen atom group is bonded.
[0019]
The present invention will be described in more detail.
The photothermographic image-forming material of the present invention has a layer structure of four or more layers in which at least two undercoat layers and a photosensitive layer and a protective layer adjacent to the photosensitive layer are provided on one side of the support. On the other hand, a backing layer and a protective layer for the backing layer are provided on the opposite side of the photosensitive layer, and the constituent layer contains “a compound in which a photographically useful group is bonded to the fullerene molecule” or the photosensitive layer contains Used for chemical sensitization of contained silver halide grains. The meaning of the usefulness of the photographically useful group means suppression of fogging, improvement of sensitivity, sharpness, raw storage, image storage, color tone, antistatic performance, scratch resistance, transportability, coating uniformity, friction coefficient. It is an improvement in performance including physical properties such as control, and means that at least one of the photographic performance items is improved.
[0020]
Hereinafter, various compounds in which a photographically useful group is bonded to the fullerene molecule of the photothermographic image forming material of the present invention will be described.
[0021]
(Fullerene compounds bonded to ionic or nonionic groups)
“Fullerene compounds having an ionic or nonionic group” are obtained by reacting a compound having an aromatic ring or vinyl group having an alkoxy group or an alkyl carboxyl group with a fullerene molecule, and then hydrolyzing the alkoxy group or the alkyl carboxyl group. Converts to hydroxyl or carboxyl group. A compound having a polyethylene oxide group is condensed on a converted hydroxyl group or carboxyl group to condense or add a nonionic group and a compound having an alkylsulfonic acid group or an alkylsulfoester group to form a compound having an anionic group. These have excellent coating properties and antistatic performance. In particular, a compound having a polyalkylene oxide group in the center and fullerene molecular parts at both ends is effective for antistatic. Preferred specific examples are shown in S1 to S5 and AS1 to AS5.
[0022]
[Chemical 1]

[0023]
[Chemical formula 2]

[0024]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1m²1 × 10 per^-6-10^-1Moles, preferably 1 × 10^-Five~ 1x10^-2Is a mole.
[0025]
(Fullerene compound bonded to UV absorbing group)
The method of bonding an ultraviolet absorber to a fullerene molecule can introduce a hydroxyl group or a carboxyl group into fullerene in the same manner as the method of reacting an ionic group or a nonionic group to the fullerene molecule, and bond the ultraviolet absorber. . As the ultraviolet absorber to be bonded, it is preferable to use a component of a compound having a benzophenone skeleton, a compound having a benzotriazole skeleton, or a compound having a cyanovinyl skeleton, and particularly preferably a benzophenone skeleton and a benzotriazole skeleton. The fullerene compound bonded to the ultraviolet absorber is added to the constituent layer of the photothermographic material of the present invention as a fullerene compound having an ultraviolet absorbing group, and is used for indoor exposure using a fluorescent lamp containing ultraviolet rays or at least on the Schaukasten. Suppresses the increase in concentration. Preferred specific examples are shown below as UV1 to UV5.
[0026]
[Chemical Formula 3]

[0027]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1m²1 × 10 per^-6-10^-1Moles, preferably 1 × 10^-Five~ 1x10^-2Is a mole.
[0028]
(Fullerene compound having a group that crosslinks to the binder via the crosslinking agent)
A fullerene compound having a group that crosslinks to a binder via a crosslinking agent can introduce a compound having an active methylene group, an epoxy group, a hydrazine group, or an alkylene hydroxyl group into the fullerene molecule by addition or condensation. The fullerene compound is bonded to the binder by a crosslinking agent. By bonding to the binder, film peeling in the production of the photothermographic image forming material of the present invention can be prevented, and the cause of image defects due to contamination can be eliminated. Alternatively, contamination in the developing device due to transpiration, volatilization, melting, or the like due to heat during development can be prevented. Preferred specific examples are shown below.
[0029]
[Formula 4]

[0030]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and peeling can be prevented, and an aromatic system such as toluene and xylene can be arbitrarily selected. The amount used is 1m²1 × 10 per^-6-10^-1Moles, preferably 1 × 10^-Five~ 1x10^-2Is a mole.
[0031]
(Crosslinking agent that crosslinks fullerene molecules having a crosslinkable group to a binder)
Preferred crosslinking agents for the present invention are compounds having an isocyanate group, a vinylsulfonyl group or an epoxy group. Particularly preferred crosslinking agents include polyfunctional crosslinking agents having at least two isocyanate groups, vinylsulfonyl groups or epoxy groups. Preferred crosslinking agents are shown in the following (H1) to (H16).
[0032]
(H1) Hexamethylene diisocyanate
(H2) Hexamethylene diisocyanate trimer
(H3) Tolylene diisocyanate
(H4) Phenylene diisocyanate
(H5) Xylylene diisocyanate
(H6) 1,3-bis (isocyanatomethyl) cyclohexane
(H7) Tetramethylene xylylene diisocyanate
(H8) m-isopropenyl-α, α-dimethylbenzyl isocyanate
[0033]
[Chemical formula 5]

[0034]
The crosslinking agent may be added after being dissolved in water, alcohols, ketones or nonpolar organic solvents, or may be added as a solid in the coating solution. The addition amount is preferably equivalent to the cross-linking group, but it may be increased up to 10 times or may be reduced to 1/10 or less. If the amount is too small, the crosslinking reaction does not proceed. If the amount is too large, an unreacted crosslinking agent deteriorates the photographic properties, which is not preferable.
[0035]
(Spectral sensitizing dye combined with fullerene molecule)
The silver halide used in the present invention can be sensitized with a spectral sensitizing dye in which a sensitizing dye skeleton is bonded to a fullerene molecule. The method for introducing the sensitizing dye skeleton into the fullerene molecule can be the same as the synthesis of the fullerene compound described above. You may use together the compound which does not have a fullerene molecular part as a spectral sensitizing dye. For example, JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, JP-A-63-15245, U.S. Pat. No. 4,639, No. 414, No. 4,740,455, No. 4,741,966, No. 4,751,175, No. 4,835,096, etc. Can be used. Preferred specific examples of the spectral sensitizing dye having a fullerene molecular part are shown below.
[0036]
[Chemical 6]

[0037]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1 x 10 per mole of silver.^-8-10^-2Moles, preferably 1 × 10^-7~ 1x10^-2Is a mole.
[0038]
(Dye combined with fullerene molecule)
The photothermographic image-forming material of the present invention is provided with an anti-halation or anti-halation AH layer or BC layer of the photothermographic image-forming material, if necessary, and as a dye used for the AH layer or BC layer, fullerene A dye having a molecular part is used. The method of introducing the dye skeleton into the fullerene molecule can be the same as the synthesis of the fullerene compound described above. Moreover, you may use a normal dye, without using the dye which does not have a fullerene molecular part. Preferred examples include dyes described in JP-A-2-216140, JP-A-7-13295, JP-A-7-11432, US Pat. No. 5,380,635, and the like. You may use together the dye which has a fullerene molecular part, and the dye which does not have a fullerene molecular part. Preferred specific examples of the dye having a fullerene molecular part are shown below.
[0039]
[Chemical 7]

[0040]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1m²1 × 10 per^-6-10^-1Moles, preferably 1 × 10^-6~ 1x10^-2Is a mole.
[0041]
(Coloring agent combined with fullerene molecule)
The photothermographic image-forming material of the present invention preferably contains a toning agent that adjusts the color of the silver image. As the color toning agent, phthalazine or a phthalazine derivative can be used, but a fullerene compound in which a fullerene molecule is bonded to phthalazine or a phthalazine derivative is preferably used. The method of binding the color tone to the fullerene molecule is the same as described above by condensing or adding the hydroxyl group, amino group, carboxyl group or vinyl group of the color tone agent to the functional group such as hydroxyl group or carboxyl group introduced into the fullerene molecule part. It is possible to synthesize a colorant bonded to a fullerene molecule. Specific examples having preferred fullerene molecular parts are shown below.
[0042]
[Chemical 8]

[0043]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1 x 10 per mole of silver.^-8-10^-2Moles, preferably 1 × 10^-7~ 1x10^-2Is a mole.
[0044]
(Fog inhibitor having fog inhibitor bonded to fullerene molecule)
The photothermographic image-forming material of the present invention preferably contains a fog inhibitor, and the fog inhibitor is an atom called a heteroatom such as a sulfur atom, a nitrogen atom or an oxygen atom having a group adsorbed on silver halide. However, it is preferable to use a fullerene compound in which a fog-inhibiting group containing these heteroatoms is bonded to a fullerene molecule. In the same way as described above, the fog suppression group is bonded to the fullerene molecule by condensing or adding a hydroxyl group, an amino group, a carboxyl group, a vinyl group or the like to the functional group such as a hydroxyl group or a carboxyl group introduced into the fullerene molecule portion. Thus, a fog inhibitor combined with a fullerene molecule can be synthesized. As the fog-inhibiting group having a hetero atom, 1-phenyl-5-mercaptotetrazole, benzotriazole, benzimidazole, indazole group each optionally having a substituent such as a halogen atom, an alkyl group, an alkoxy group, or a phenyl group , Tetrazole group, triazine group, tetrazaindene group, purine group, imidazole group, or triazole group. Preferred specific examples of the inhibitor having a preferred fullerene molecular part are shown below.
[0045]
[Chemical 9]

[0046]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1 x 10 per mole of silver.^-8-10^-2Moles, preferably 1 × 10^-7~ 1x10^-2Is a mole.
[0047]
(Compounds with light-resistant groups bonded to fullerene molecules)
The photothermographic image-forming material of the present invention preferably contains a light fastness improver, and as the light fastness improver, a compound having a group capable of releasing a halogen radical can be used. It is preferable to use a fullerene compound in which is bonded to a fullerene molecule. The method of bonding the light resistance improving group to the fullerene molecule is the same as the fullerene compound, such as a hydroxyl group, an amino group, a carboxyl group, a vinyl group, or the like of the light resistance improving group portion on a functional group such as a hydroxyl group or a carboxyl group introduced into the fullerene molecule portion It can be synthesized by condensation or addition. The group capable of releasing a halogen radical is preferably a polyhalomethane group, particularly a tribromomethyl group having an aromatic ring (benzene ring, naphthalene ring, etc.) or a hetero ring having a hetero atom (pyridine ring, triazine ring, pyrimidine ring, quinoline ring). , A pyrimidine ring, a furan ring, and the like), and a linking group to be bonded to a polyhalomethyl group and an aromatic ring group or a heterocyclic group is a sulfur atom or nitrogen atom such as a sulfonyl group, a sulfonamide group, or a carboamide group. Groups containing are preferred. Preferable specific examples of the light resistance improver having a fullerene molecular part are shown below.
[0048]
Embedded image

[0049]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1 x 10 per mole of silver.^-8-10^-2Moles, preferably 1 × 10^-7~ 1x10^-2Is a mole.
[0050]
(Chemical sensitizer in which a group having an unstable chalcogen atom group is bonded to the fullerene molecule)
The photosensitive silver halide is chemically sensitized with a sensitizer in which an unstable chalcogen atom group is bonded to the fullerene molecule. The chalcogen atom is preferably a sulfur, selenium or tellurium atom. Alternatively, chemical sensitization can be performed by combining these sensitizers with gold compounds, platinum compounds, and palladium compounds. In order to bond an unstable chalcogen atom group to a fullerene molecule, after introducing a hydroxyl group or a carboxyl group into the fullerene molecule, a skeleton structure of a chemical sensitizer having an unstable chalcogen atom is introduced by condensation or addition reaction. Can be synthesized. Preferred specific examples are shown below.
[0051]
Embedded image

[0052]
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount used is 1 x 10 per mole of silver.^-8-10^-2Moles, preferably 1 × 10^-7~ 1x10^-2Is a mole.
[0053]
A method for synthesizing the fullerene compound of the present invention will be described. First, four representative intermediates were synthesized. The reaction scheme is shown below.
[0054]
Embedded image

[0055]
Embedded image

[0056]
Synthesis of intermediate 1 (cpd-1)
In a four-necked flask equipped with a stirrer, a thermometer, and a blowing tube, 960 ml of dry toluene was added to fullerene (C₆₀) 2.0 g (2.76 mmol) and 1.67 g (4.5 mmol) of tetrabutylammonium iodide were dissolved, and 1.34 g (4.2 mmol) of 1,2-dibromomethyl-4,5-dimethoxybenzene was charged. The solution was refluxed for 10 hours under light shielding. The mixture was allowed to cool to room temperature, washed with water, and purified by silica gel chromatography using a 3: 1 toluene: hexane solvent. While maintaining 124 mg (0.14 mmol) of this compound in a dry toluene solution at 0 ° C., 0.8 ml (9.2 ml) of boron tribromide was added and reacted for 12 hours. After the reaction, unreacted boron tribromide was removed with cold water, extracted with ethyl acetate, and dried over magnesium sulfate. The purified product was purified by reprecipitation with THF / hexane.
[0057]
Synthesis of intermediate 2 (cpd-2)
In a four-necked flask equipped with a stirrer, a thermometer, and a blowing tube, 960 ml of dry toluene was added to fullerene (C₆₀) 2.0 g (2.76 mmol) and 1.67 g (4.5 mmol) of tetrabutylammonium iodide were dissolved, and 1.12 g (4.2 mmol) of 1,2-dibromomethyl-4-methoxybenzene was added, and light-shielded. The bottom was refluxed for 12 hours. The mixture was allowed to cool to room temperature, washed with water, and purified by silica gel chromatography using a 3: 1 toluene: hexane solvent. While keeping 104 mg (0.14 mmol) of this compound in a dry toluene solution at 0 ° C., 0.8 ml (9.2 ml) of boron tribromide was added and reacted for 12 hours. After the reaction, unreacted boron tribromide was removed with cold water, extracted with ethyl acetate, and dried over magnesium sulfate. The purified product was purified by reprecipitation with THF / hexane.
[0058]
Synthesis of intermediate 3 (cpd-3)
In a four-necked flask equipped with a stirrer, a thermometer, and a blow-in tube, 980 ml of dry toluene was added to fullerene (C₆₀) 2.0 g (2.76 mmol) and 1.67 g (4.5 mmol) of tetrabutylammonium iodide were dissolved, and 1.24 g (4.2 mmol) of 1,2-dibromomethyl-4-carboxymethylbenzene was charged. Reflux was carried out for 21 hours in the dark. The mixture was allowed to cool to room temperature, washed with water, and purified by silica gel chromatography using a 3: 1 toluene: hexane solvent. While maintaining 128 mg (0.14 mmol) of this compound in a dry toluene solution at 0 ° C., 0.8 ml (9.2 ml) of boron tribromide was added and reacted for 12 hours. After the reaction, unreacted boron tribromide was removed with cold water, extracted with ethyl acetate, and dried over magnesium sulfate. The purified product was purified by reprecipitation with THF / hexane.
[0059]
Synthesis of intermediate 4 (cpd-4)
In a four-necked flask equipped with a stirrer, thermometer, and blowing tube, 930 ml of dry toluene was added to fullerene (C₆₀) 2.0 g (2.76 mmol) and 1.67 g (4.5 mmol) of tetrabutylammonium iodide were dissolved, and 1.24 g (4. 4) of 1,4-dibromo-2-carboxymethyl-2,3-butylene was dissolved. 2 mmol), and refluxed for 21 hours in the dark. The mixture was allowed to cool to room temperature, washed with water, and purified by silica gel chromatography using a 3: 1 toluene: hexane solvent. While maintaining 108 mg (0.14 mmol) of this compound in a dry toluene solution at 0 ° C., 0.8 ml (9.2 ml) of boron tribromide was added and reacted for 12 hours. After the reaction, unreacted boron tribromide was removed with cold water, extracted with ethyl acetate, and dried over magnesium sulfate. The purified product was purified by reprecipitation with THF / hexane.
[0060]
Synthesis of S1
Into a 1 L autoclave purged with nitrogen, 2.2 g of intermediate 1 (cpd-1) and 2.3 g of polyethylene glycol (molecular weight 898) were introduced, and 0.2 g of concentrated sulfuric acid was added dropwise and reacted at 58 ° C. for 1 hour. Thereafter, the reaction mixture was poured into 2 L of toluene, and the resulting solid was collected by filtration and dried at room temperature under a nitrogen stream to obtain a powdery solid. Thereafter, S2 to S5 were synthesized in the same manner.
[0061]
Synthesis of AS2
Into a 1 L autoclave purged with nitrogen, 2.1 g of intermediate 2 (cpd-2) and 2.2 g of polyethylene glycol (molecular weight 898) were introduced, and 0.2 g of concentrated sulfuric acid was added dropwise and reacted at 78 ° C. for 1 hour. Thereafter, the reaction mixture was poured into 2 L of toluene, and the resulting solid was collected by filtration and dried at room temperature under a nitrogen stream to obtain a powdery solid. Subsequently, AS1, AS3 to AS5 were synthesized in the same manner.
[0062]
Synthesis of UV1
Into a 1 L autoclave substituted with nitrogen, 2.2 g of intermediate 4 (cpd-4) and 0.3 g of 2- (2-hydroxy-5-hydroxyethylphenyl) benzotriazole were introduced, and 0.2 g of concentrated sulfuric acid was added dropwise. After reacting at 78 ° C. for 1 hour, the reaction mixture was poured into 2 L of toluene, and the resulting solid was collected by filtration and dried at room temperature under a nitrogen stream to obtain a powdery solid. Thereafter, UV2 to UV5 were synthesized in the same manner.
[0063]
Synthesis of LP1
Into a 1 L autoclave substituted with nitrogen, 2.2 g (2.3 mmol) of intermediate 4 (cpd-4) and 2.65 g (2.3 mmol) of 4-amino-4-methyl-2-pentanone were introduced and concentrated sulfuric acid. Was added dropwise at 68 ° C. for 1 hour, the reaction mixture was poured into 2 L of toluene, and the resulting solid was collected by filtration and dried at room temperature under a nitrogen stream to obtain a powdered solid. Thereafter, LP2 to LP5 were synthesized by reacting intermediate 4 with epochorohydrin, p-aminophenylhydrazine, hydroxyethoxyethyl alcohol and ethylenediamine as intermediates.
[0064]
Synthesis of DE1 to DE3 and DS1 to DS3
In the same manner as AS1, heptamethine cyanine dye was reacted with intermediate 2 to obtain DE1 to DE3 and DS1 to DS3.
[0065]
Synthesis of AF1
In the same manner as in the synthesis of LP1, 1 was reacted with 1- (p-hydroxyphenyl) -5-mercapto-tetrazole to obtain AF1. AF2 to AF4 were synthesized by reacting 5-hydroxybenzotriazole, 5-hydroxybenzimidazole, 5-aminoindazole and the like. AF5 was synthesized by reacting 3,4-dimethylthiobenzoyl chloride and hydrolyzing it.
[0066]
Synthesis of TN1
Although it synthesize | combined similarly to said AF1, here, 5-hydroxy-aziridine was made to react. Similarly, TN5 was obtained from TN2.
[0067]
Synthesis of HL1
In the same manner as in the synthesis of S1, intermediate 1 was reacted with 1-carboxy-4-tribromomethylbenzene. Similarly, HL2 to HL5 were obtained.
[0068]
Synthesis of ST1 to ST5
Although it carried out similarly to the synthesis | combination of said LP1, the thiourea was made to react with the intermediate body 4 here. Selenourea, p-aminotellururea, p-aminoselenourea and p-amino-perfluorophenylselenourea were then reacted for synthesis.
[0069]
(Organic silver salt)
The organic silver salt contained in the photothermographic image-forming material of the present invention is a reducible silver source, and organic acids, heteroorganic acids and acid polymer silver salts containing a reducible silver ion source are used. Also useful are organic or inorganic silver salt complexes whose ligands have a total stability constant for silver ions of 4.0-10.0. Examples of silver salts are described in Research Disclosure Nos. 17029 and 29963 and include the following: salts of organic acids (eg, gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid, etc. Salt) etc. The amount of organic silver used is preferably from 1/10 to 100 mol per mol of silver halide.
[0070]
(Reducing agent)
Examples of preferable reducing agents contained in the photothermographic image-forming material of the present invention are described in U.S. Pat. Nos. 3,770,448, 3,773,512, 3,593,863, etc. And Research Disclosure Nos. 17029 and 29963, including the following:
[0071]
K1: 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane
K2: bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane
K3: 2,2-bis (4-hydroxy-3-methylphenyl) propane
K4: 4,4-ethylidene-bis (2-tert-butyl-6-methylphenol)
K5: 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane
The compounds shown above are used by dispersing in water or dissolving in an organic solvent. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic systems such as toluene and xylene can be arbitrarily selected. The amount of reducing agent used is 1 x 10 per mole of silver.^-2-10 mol, preferably 1 x 10^-2~ 3 moles.
[0072]
(Photosensitive silver halide grains)
The photosensitive silver halide contained in the photosensitive layer of the photothermographic image-forming material of the present invention can be obtained by any method known in the field of photographic technology such as a single jet or double jet method, for example, an ammonia emulsion or neutral emulsion. It can be prepared in advance by any method such as a method or an acidic method, and then mixed with the other components of the present invention and introduced into the composition used in the present invention. In this case, in order to sufficiently contact the photosensitive silver halide and the organic silver salt, for example, U.S. Pat. Nos. 3,706,564 and 3,706 are used as protective polymers when preparing the photosensitive silver halide. , 565, 3,713,833, 3,748,143, British Patent 1,362,970, etc., and means using a polymer other than gelatin such as polyvinyl acetals Or means for enzymatic degradation of gelatin in light sensitive silver halide emulsions as described in British Patent 1,354,186, or as described in US Pat. No. 4,076,539. Thus, each means such as a means for omitting the use of the protective polymer can be applied by preparing photosensitive silver halide grains in the presence of a surfactant.
[0073]
The photosensitive silver halide preferably has a small grain size in order to keep white turbidity after image formation low and to obtain good image quality. The average particle size is 0.1 μm or less, preferably 0.01 to 0.1 μm, particularly preferably 0.02 to 0.08 μm. Further, the shape of the silver halide is not particularly limited, and examples thereof include cubic and octahedral so-called normal crystals and non-normal crystals such as spherical, rod-like, and tabular grains. The silver halide composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.
[0074]
The amount of the silver halide is 50% by mass or less, preferably 25 to 0.1% by mass, more preferably 15 to 0.1% by mass, based on the total amount of the silver halide and the organic silver salt described later. Various conditions such as reaction temperature, reaction time, reaction pressure, etc. in the step of converting a part of the organic silver salt into silver halide using the above-mentioned silver halide forming component can be appropriately set according to the purpose of preparation. Usually, the reaction temperature is −23 ° C. to 74 ° C., the reaction time is 0.1 seconds to 72 hours, and the reaction pressure is preferably set to atmospheric pressure.
[0075]
(Binder)
Examples of the polymer binder used in the photosensitive layer or the non-photosensitive layer of the photothermographic image forming material of the present invention include polyvinyl butyral, polyacrylamide, polystyrene, polyvinyl acetate, polyurethane, polyacrylate, and styrene-butadiene copolymer. Acrylonitrile-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, styrene-butadiene-acrylic copolymer, and the like. Further, after drying, a film is formed, and those having a low equilibrium moisture content of the coating film are preferable. Examples of particularly low moisture content include organic solvent-based cellulose acetate, cellulose acetate butyrate and polyacetal. it can. Polyacetal means a polymer obtained by producing polyvinyl alcohol by saponifying polyvinyl acetate and reacting the polyvinyl alcohol with an aldehyde compound. Polyacetal preferred in the present invention is a polyacetal acetalized with butyraldehyde. Polyacetal acetalized with butyral or acetaldehyde (polyacetal in a narrow sense) is preferred. Acetalization theoretically exists from 1% to 100%, but practically 20% to 95% is preferable. When the degree of acetalization is low, the number of hydroxyl groups increases, and the photographic performance is sensitive to humidity. When the degree of acetalization is high, the reaction temperature and time become severe, and the cost and productivity decrease. For water-based coatings, water-dispersed polymer styrene and butadiene copolymer, styrene and alkyl acrylate or alkyl methacrylate ester copolymer, acrylic acid alkyl ester and methacrylate alkyl ester copolymer Can be mentioned. Further, the water-dispersed polymer is preferably a fine particle having an average particle diameter in the range of 1 nm to several μm and dispersed in an aqueous dispersion medium. The water-dispersed polymer is particularly preferably hydrophobic because it can improve water resistance among the widely used binders for aqueous coating. The degree of polymerization of the polymer can be freely selected from about 10 to about 10,000, but 100 to 6000 is preferable from the viewpoint of coating property and productivity when synthesizing.
[0076]
(Support)
As the support, a support such as polyethylene terephthalate, polyethylene naphthalate or syndiotactic polystyrene is preferable, and biaxially stretched or heat-set optically isotropic, having a thickness of 50 μm to 400 μm with good dimensional stability Is good.
[0077]
<Image exposure>
As an exposure method, laser exposure can be performed by the methods described in JP-A-9-304869, JP-A-9-311403 and JP-A-2000-10230. In the exposure of the photothermographic image forming material of the present invention, it is desirable to use a light source suitable for the color sensitivity imparted to the photosensitive material. For example, in the case where the light-sensitive material can be felt by 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.
[0078]
<Heat development device>
As an apparatus for developing the photothermographic image forming material, apparatuses described in JP-A Nos. 11-65067, 11-72897 and 11-84619 can be used.
[0079]
【Example】
Examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.
[0080]
Example 1
(Production of photothermographic image forming material)
<Preparation of underdrawn support>
12 W / m on both sides of a 175 μm thick polyethylene terephthalate support²・ Corona discharge treatment was performed for one minute, and the following undercoat coating solution a-1 was applied on one surface to a dry film thickness of 0.6 μm and dried to provide an undercoat layer A-1, and on the other side The undercoat coating solution b-1 shown below was applied on the surface so as to have a dry film thickness of 0.6 μm and dried to provide an undercoat layer B-1.
[0081]
<< Undercoat coating liquid a-1 >>
Butyl acrylate (30% by mass)
t-Butyl acrylate (20% by mass)
Styrene (25% by mass)
2-Hydroxyethyl acrylate (25% by mass)
The copolymer latex liquid (solid content 30%) is diluted 15 times.
[0082]
<< Undercoating liquid b-1 >>
Butyl acrylate (40% by mass)
Styrene (20% by mass)
Glycidyl acrylate (40% by mass)
The copolymer latex liquid (solid content 30%) is diluted 15 times.
[0083]
Subsequently, 12 W / m is applied to the upper surface of the undercoat layer A-1 and the undercoat layer B-1.²・ Corona discharge was applied for a minute. On the undercoat layer A-1, the following undercoat upper layer coating solution a-2 was applied and dried to provide the undercoat upper layer A-2 (for the photosensitive layer side). On the layer B-1, the following undercoat upper layer coating solution b-2 was applied and dried to provide an undercoat upper layer B-2 (for BC layer) having an antistatic function.
[0084]
<< Undercoating upper layer coating liquid a-2 >>
Styrene and butadiene 1: 2 copolymer 0.4 g / m²
Butyl acrylate (30% by mass)
t-Butyl acrylate (20% by mass)
Styrene (25% by mass)
2-hydroxyethyl acrylate (20% by mass)
Methacrylic acid (5% by mass)
Copolymer latex liquid (solid content 30%) 0.3 g / m²
<< Undercoating Upper Layer Coating Liquid b-2 >>
Styrene and butadiene 1: 2 copolymer 0.4 g / m²
Butyl acrylate (30% by mass)
t-Butyl acrylate (20% by mass)
Styrene (25% by mass)
2-hydroxyethyl acrylate (20% by mass)
Methacrylic acid (5% by mass)
Copolymer latex liquid (solid content 30%) 0.3 g / m²
On the prepared undercoat support, an AH layer, a photosensitive layer and a photosensitive layer protective layer having the following composition were applied simultaneously. Prior to the photosensitive layer, the BC layer and the BC layer protective layer are simultaneously laminated in advance, but this may be reversed, or the photosensitive layer and the BC layer side may be laminated simultaneously.
[0085]
First, silver halide was prepared prior to coating, and then an organic silver salt was prepared using the prepared silver halide.
[0086]
<Preparation of silver halide grain emulsion A>
After dissolving 7.5 g of inert gelatin and 10 mg of potassium bromide in 900 ml of water and adjusting the temperature to 28 ° C. and pH to 3.0, bromide with a molar ratio of (98/2) to 370 ml of an aqueous solution containing 74 g of silver nitrate 370 ml of an aqueous solution containing 0.436 mol of potassium and potassium iodide was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. Synchronous with the addition of silver nitrate, the sodium salt of hexachloroiridium is 1 × 10^-6Mole / silver 1 mol was added. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.036 μm, and the variation coefficient of the projected diameter area was 8%. Cubic silver iodobromide grains having a [100] face ratio of 87% were obtained. This emulsion was coagulated and settled using a gelatin flocculant, desalted, and then added with water to make a final volume of 160 ml.
[0087]
<Preparation of water-dispersed organic silver salt>
In 3980 ml of pure water, 111.4 g of behenic acid, 83.8 g of arachidic acid, and 54.9 g of stearic acid were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 molar sodium hydroxide aqueous solution was added while stirring at high speed, and 6.9 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain an organic acid sodium solution. While maintaining the temperature of the organic acid sodium solution at 55 ° C., the silver halide grain emulsion A (containing 0.038 mol of silver) and 420 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of 1 mol silver nitrate solution was added over 2 minutes, and the mixture was further stirred for 20 minutes, and water-soluble salts were removed by filtration. Thereafter, the filtrate was repeatedly washed with deionized water and filtered until the electrical conductivity of the filtrate reached 2 μS / cm, and finally dried after dehydration at the center.
[0088]
<Coating of photosensitive layer and BC layer>
The following layers on the photosensitive layer side and BC side were coated on the support on which the undercoat layer had been applied. The drying was performed at 45 ° C. for 1 minute on both the photosensitive layer side and the BC side.
[0089]
(BC layer side coating)
On the back surface side, a BC solution layer was formed by simultaneously applying and drying a coating solution prepared with the following composition so as to have the following amount.
[0090]
<< BC layer application >>
Binder: PVB-1 1.8 g / m²
Hexamethylene diisocyanate 1 × 10^-FourMol / m²
Dye: C1 2.2 × 10^-FiveMol / m²
<< Application of BC protective layer >>
Cellulose acetate butyrate 1.1 g / m²
Hexamethylene diisocyanate 1 × 10^-FourMol / m²
(Coating on the photosensitive layer side)
<Application of AH layer>
Binder: PVB-1 0.4 g / m²
Dye: C1 1.3 × 10^-FiveMol / m²
<Application of photosensitive layer>
In order to form a photosensitive layer, a coating solution of the following composition was prepared and applied and dried so as to have the following amount. 1.36 g / m as the amount of silver²An amount of the organic silver salt preparation was mixed with a polymer binder.
[0091]

[0092]
Embedded image

[0093]
<Surface protective layer>
A coating solution prepared by adding the following composition was applied and dried on the photosensitive layer so as to have the following weight to form a surface protective layer.
[0094]

PVB-1 was used after saponifying 98% of polyvinyl acetate having a polymerization degree of 500 and then butylating 86% of the remaining hydroxyl groups. PVB-1 was also used as a binder for the BC layer. As a comparison of the ionic compounds, the sulfonic acid ester of lauryl alcohol was a ref-1 compound, and the nonionic compound was an ester compound of stearic acid and a polyethylene glycol having a polymerization degree of 20 was ref-2.
[0095]
(Evaluation of photographic performance)
The prepared sample is exposed to a 810 nm semiconductor laser exposure sensitometer in an atmosphere of 48% relative humidity at 25 ° C., and after heating for 8 seconds at 120 ° C., the fog and sensitivity of the obtained sample are obtained. It was. Sensitivity was calculated from the reciprocal of the exposure amount giving fog + density 0.3, and the first relative sensitivity of the sample number was 100.
[0096]
(Evaluation of applicability)
Using a multi-layer coating tester, apply a uniform solid exposure to a sample with a width of 50 cm and a length of 1 m on which AH layer, photosensitive layer and protective layer are simultaneously coated, and develop it to a density of 1.0 ± 0.1. Evaluated. The development process was performed by shifting the 90 ° C. direction so that the development direction and the coating direction were not the same so that the development unevenness and the coating unevenness could be distinguished. The coating property was evaluated as the uniformity of coating by measuring the density of 1000 samples in the sample, dividing the standard deviation of the density by the average density and multiplying by 100. Levels with a standard deviation of 50 or more are set to 1, levels with a standard deviation of 30 to 50 are set to 2, levels with a standard deviation of 20 to 30 are set to 3, levels with a standard deviation of 15 to 20 are set to 4, and levels with a standard deviation of 15 or less are set to 5. . The practically no problem level is 3. The experimental results are shown in Table 1. Incidentally, methyl ethyl ketone was used as a coating solvent, and a coating solution was prepared with a solid content concentration of 32%.
[0097]
(Antistatic performance)
The coated sample of 5 cm × 15 cm was left in a room with a relative humidity of 20% for 10 hours, and then the surface was rubbed five times with a nylon cloth to evaluate the degree of adsorbing and adsorbing 2 mm diameter foamed styrene beads. The level with the most adhesion was 1, the level with little adhesion was 5, and the level with no practical problem was 3. Table 1 shows the experimental contents and experimental results.
[0098]
[Table 1]

[0099]
From Table 1, it can be seen that when the ionic or anionic fullerene compound of the present invention is used, the coating property is improved and the antistatic effect is improved without adversely affecting the photographic performance.
[0100]
Example 2
An experiment was conducted in the same manner as in Example 1, but an ultraviolet absorber was added in place of the ionic or nonionic compound, and photographic performance and light resistance were evaluated. In the light resistance test, two 40 watt ultraviolet fluorescent lamps (fluorescent tube FL40SD manufactured by Matsushita Electric Works Co., Ltd.) were arranged in parallel, and the developed sample was left immediately under 2 m, and the density increase in the unexposed area was measured.
[0101]
In addition, the comparative ultraviolet absorber described benzophenone as ref-3 and 2- (2-hydroxy-5-ethylphenyl) benzotriazole as ref-4. In addition, an experiment for adding to the photosensitive layer was also conducted. The amount added per area was the same. Table 2 shows the experimental contents and experimental results.
[0102]
[Table 2]

[0103]
It can be seen from Table 2 that the fullerene compound having an ultraviolet absorbing group of the present invention improves light resistance without deteriorating photographic performance.
[0104]
Example 3
A sample was prepared in the same manner as in Example 1. Here, as the fullerene compound, a compound in which a “group bonded through a crosslinking agent” was bonded to the fullerene molecule was used, and at the same time, the peeling resistance was evaluated using the crosslinking agent. did. For the peeling property, a test sample was transported at a speed of 300 m / min for 30 minutes by a transportability tester in which 20 opposed rollers were arranged, and the dirt adhered to the surface of the transport roller was evaluated. It was observed with a magnifier of 200 times, and the most dirty level was evaluated as 1, the level without contamination as 5, and the level with no practical problem even when there was contamination as 3 was evaluated. The results are shown in Table 3.
[0105]
[Table 3]

[0106]
From Table 3, it can be seen that the use of a compound in which a group bonded through the crosslinking agent of the present invention is bonded to a fullerene molecule suppresses contamination of the roller in high-speed conveyance.
[0107]
Example 4
A test sample was prepared in the same manner as in Example 1. Here, a chemical sensitizer having an unstable chalcogen group bonded to a fullerene molecule was used for chemical ripening of silver halide. Chemical ripening is performed for 10 mol of silver halide per 1 mol of silver halide grains after desalting.^-6Mole was added and chemical ripening was performed at 55 ° C. for 1 hour. Here, a sample was prepared without using the fullerene compound added to the protective film in Example 1. For comparison of chemical sensitizers, diphenylthiourea (DPTU) was used. The experimental contents and results are shown in Table 4 below.
[0108]
[Table 4]

[0109]
From Table 4, it can be seen that when sensitization is performed with a chemical sensitizer in which an unstable chalcogen group is bonded to the fullerene molecule of the present invention, fog does not increase and sensitivity is high.
[0110]
Example 5
Samples were prepared in the same manner as in Example 1. Samples 502 to 508 were prepared according to the present invention shown in Additive 1 in Table 5 in place of the spectral sensitizing dye (ref-5) used in Example 1 for the photosensitive layer. Spectral sensitizing dye 3 × 10 per mole of silver halide^-FiveMole was added. In addition, with ref-5 as additive 2, in samples 506 to 508, 3 × 10 5 per mole of silver halide.^-FiveMole was added. The fullerene compound was not added to the protective layer. As the photographic performance, fog, sensitivity and sharpness were evaluated. For the evaluation of sharpness, the modulation transfer rate was determined using an MTF (Modulation Transfer Function) chart. Table 5 shows the experimental contents and experimental results.
[0111]
[Table 5]

[0112]
From Table 5, it can be seen that the sensitivity and sharpness increase when the sensitizing dye of the present invention is used. It can also be seen that sharpness improves when used in combination with spectral sensitizing dyes.
[0113]
Example 6
A sample was prepared in the same manner as in Example 1, except that the spectral sensitizing dye of the present invention was used as an antihalation dye instead of the dye used in BC. After development, the modulation transmission was measured in the same manner as in Example 5 to evaluate the sharpness. Table 6 shows the contents of the experiment and the results obtained.
[0114]
[Table 6]

[0115]
It can be seen from Table 6 that sharpness is improved when used as an antihalation dye.
[0116]
Example 7
A sample was prepared in the same manner as in Example 1. Here, except for the fullerene compound added to the protective layer, the anti-fogging agent was used by binding the anti-fogging group to the fullerene molecule in the photosensitive layer. As a comparison of the fog inhibitor, 1-phenyl-5-mercaptotetrazole (PMT) was used, and the addition amount was 6 × 10 6 per mol of silver halide.^-FiveMole. The experimental contents and experimental results are shown in Table 7 below.
[0117]
[Table 7]

[0118]
From Table 7, it can be seen that when a fullerene compound having a fog suppression group bonded to the fullerene molecular part is used, the fog suppression property is obtained.
[0119]
Example 8
The experiment was conducted in the same manner as in Example 7. The fullerene compound added to the photosensitive layer was a fullerene compound in which a polyhalomethane group was bonded to the fullerene molecular part. Addition amount is 2.4 × 10 4 per mole of silver.^-FourMole. Tribromomethylsulfonylbenzene (ref-6) was used as a comparative compound. In the light resistance test, a sample was allowed to stand for 10 hours in a shear caster equipped with four 40-watt fluorescent tubes, and fogging at that time was evaluated.
[0120]
[Table 8]

[0121]
Table 8 shows that the fog value does not increase when a compound having a polyhalomethane group bonded to the fullerene molecular part of the present invention is used.
[0122]
Example 9
The experiment was conducted in the same manner as in Example 8. Here, as the fullerene compound added to the photosensitive layer, a fullerene compound in which a color tone group for changing the brown silver color tone to the black silver tone color was combined with the fullerene molecule portion. In the evaluation of the color tone, the darkest brown color was rated as 1 rank, and the black color was rated as 5 ranks. A practically no problem color tone was set to 3. For comparison, phthalazine (ref-7) was used. The experimental results are shown in Table 9 below.
[0123]
[Table 9]

[0124]
From Table 9, it can be seen that the color tone of the fullerene compound in which the black color tone group is bonded to the fullerene molecular part of the present invention is improved.
[0125]
【The invention's effect】
According to the present invention, a photothermographic image forming material having improved performances such as sensitivity, fog suppression, storage stability, sharpness, sensitization, color tone, and image defects was obtained.

Claims (12)

A photothermographic image forming material having at least one photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support provided with an undercoat layer. A photothermographic image-forming material comprising a compound having a photographically useful group bonded to a fullerene molecule in at least one of the layers. 2. The photothermographic image forming material according to claim 1, wherein the photographically useful group is an ionic group or a nonionic group bonded to a cyclic or acyclic hydrocarbon group. 2. The photothermographic image-forming material according to claim 1, wherein the photographically useful group is an ultraviolet absorbing group. 2. The photothermographic image forming material according to claim 1, wherein the photographically useful group is a group bonded to a binder through a crosslinking agent. The photothermographic image-forming material according to claim 4, wherein the group bonded to the binder via a crosslinking agent is an active methylene group, an epoxy group, a hydrazine group or a hydroxyl group. 6. The photothermographic image forming material according to claim 4, wherein the crosslinking agent has an isocyanate group, a vinylsulfonyl group or an epoxy group. 2. The photothermographic image-forming material according to claim 1, wherein the photographically useful group is a spectral sensitizing dye group. The photothermographic image-forming material according to claim 1, wherein the photographically useful group is an irradiation or antihalation dye group. 2. The photothermographic image forming material according to claim 1, wherein the photographically useful group is a fog suppressing group. 2. The photothermographic image-forming material according to claim 1, wherein the photographically useful group is a light fastness improver group. 2. The photothermographic image-forming material according to claim 1, wherein the photographically useful group is a color toner. In a photothermographic image-forming material having at least one photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support, the photosensitive silver halide grains are unstable to fullerene molecules. A photothermographic image-forming material which is chemically sensitized with a chemical sensitizer to which a chalcogen atom group is bonded.