JP4023072B2 - Method for producing photothermographic material - Google Patents

Description

【００５８】
式中、Ｒは水素原子または炭素原子数１〜１０のアルキル基（例えば、ブチル基、２，４，４−トリメチルペンチル基等）を表し、Ｒ′及びＲ″は炭素原子数１〜５のアルキル基（例えば、メチル基、エチル基、ｔ−ブチル基等）を表す。
【００５９】
一般式（Ａ）で表される化合物の具体例を以下に示す。ただし、本発明は、これらに限定されない。
【００６０】
【化２】

【００６１】
【化３】

【００６２】
本発明においては、前記一般式（Ａ）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１．０×１０^-2〜１０モル、更に好ましくは１．０×１０^-2〜３モルである。
【００６３】
本発明に係る熱現像感光材料には、カブリ防止剤が含まれて良い。有効なカブリ防止剤として知られているものは水銀イオンであり、感光材料中にカブリ防止剤として水銀化合物を使用することについては、例えば米国特許第３，５８９，９０３号に開示されている。しかし、水銀化合物は環境的に好ましくないので、例えば米国特許第４，５４６，０７５号及び同第４，４５２，８８５号及び特開昭５９−５７２３４号に開示されている様な非水銀カブリ防止剤が本発明においては好ましく用いられる。
【００６４】
特に好ましい非水銀カブリ防止剤としては、米国特許第３，８７４，９４６号及び同第４，７５６，９９９号に開示されているような化合物、−Ｃ（Ｘ₁）（Ｘ₂）（Ｘ₃）（ここでＸ₁及びＸ₂はハロゲン原子を表し、Ｘ₃は水素またはハロゲン原子を表す）で表される置換基を１以上備えたヘテロ環状化合物が挙げられる。
【００６５】
また、その他に好適なカブリ防止剤としては、特開平９−２８８３２８号の段落番号〔００３０〕〜〔００３６〕に記載されている化合物、特開平９−９０５５０号の段落番号〔００６２〕〜〔００６３〕に記載されている化合物、米国特許第５，０２８，５２３号及び欧州特許第６００，５８７号、同第６０５，９８１号、同第６３１，１７６号等に開示されている化合物を用いることが出来る。
【００６６】
本発明においては、非水銀カブリ防止剤を始めとするカブリ防止剤の使用量は、好ましくは銀１モル当り１．０×１０^-4〜１０モル、更に好ましくは１．０×１０^-3〜１．５モルである。
【００６７】
本発明に係る熱現像感光材料には、現像後の銀色調を改良する目的で色調剤を添加することが好ましい。好ましい色調剤の例はＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ第１７０２９号に開示されており、次のものがある。
【００６８】
イミド類（例えば、フタルイミド）；環状イミド類、ピラゾリン−５−オン類、及びキナゾリノン（例えば、スクシンイミド、３−フェニル−２−ピラゾリン−５−オン、１−フェニルウラゾール、キナゾリン及び２，４−チアゾリジンジオン）；ナフタールイミド類（例えば、Ｎ−ヒドロキシ−１，８−ナフタールイミド）；コバルト錯体（例えば、コバルトのヘキサミントリフルオロアセテート）、メルカプタン類（例えば、３−メルカプト−１，２，４−トリアゾール）；Ｎ−（アミノメチル）アリールジカルボキシイミド類（例えば、Ｎ−（ジメチルアミノメチル）フタルイミド）；ブロックされたピラゾール類（例えば、Ｎ，Ｎ′−ヘキサメチレン（１−カルバモイル−３，５−ジメチルピラゾール））、イソチウロニウム（ｉｓｏｔｈｉｕｒｏｎｉｕｍ）誘導体及びある種の光漂白剤の組み合わせ、（１，８−（３，６−ジオキサオクタン）ビス（イソチウロニウムトリフルオロアセテート）及び２−（トリブロモメチルスルホニル）ベンゾチアゾールの組み合わせ）；フタラジノン、フタラジノン誘導体またはこれらの誘導体の金属塩（例えば、４−（１−ナフチル）フタラジノン、６−クロロフタラジノン、５，７−ジメチルオキシフタラジノン、及び２，３−ジヒドロ−１，４−フタラジンジオン）；フタラジノンとスルフィン酸誘導体の組み合わせ（例えば、６−クロロフタラジノン＋ベンゼンスルフィン酸ナトリウムまたは８−メチルフタラジノン＋ｐ−トリスルホン酸ナトリウム）；フタラジン＋フタル酸の組み合わせ；フタラジン（フタラジンの付加物を含む）とマレイン酸無水物、及びフタル酸、２，３−ナフタレンジカルボン酸またはｏ−フェニレン酸誘導体及びその無水物（例えば、フタル酸、４−メチルフタル酸、４−ニトロフタル酸及びテトラクロロフタル酸無水物）から選択される少なくとも１つの化合物との組み合わせ；キナゾリンジオン類、ベンゾオキサジン、ナルトキサジン誘導体；ベンゾオキサジン−２，４−ジオン類（例えば、１，３−ベンゾオキサジン−２，４−ジオン）；ピリミジン類及び不斉−トリアジン類（例えば、２，４−ジヒドロキシピリミジン）、及びテトラアザペンタレン誘導体（例えば、３，６−ジメルカプト−１，４−ジフェニル−１Ｈ，４Ｈ−２，３ａ，５，６ａ−テトラアザペンタレン）。好ましい色調剤としてはフタラジノンまたはフタラジンである。
【００６９】
本発明においては、フタラゾンまたはフタラジンを始めとする色調剤の使用量は、好ましくは銀１モル当り１．０×１０^-3〜１０モル、更に好ましくは１．０×１０^-2〜５モルである。
【００７０】
本発明に係る熱現像感光材料には、例えば特開昭６３−１５９８４１号、同６０−１４０３３５号、同６３−２３１４３７号、同６３−２５９６５１号、同６３−３０４２４２号、同６３−１５２４５号、米国特許第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号に記載された増感色素が使用できる。
【００７１】
本発明に好ましく使用される有用な増感色素は例えばＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ Ｉｔｅｍ１７６４３IV−Ａ項（１９７８年１２月ｐ．２３）、同Ｉｔｅｍ１８４３１（１９７９年８月ｐ．４３７）等に記載もしくは引用された文献に記載されている。特に各種スキャナー光源の分光特性に適した分光感度を有する増感色素を有利に選択することができる。例えば特開平９−３４０７８号、同９−５４４０９号、同９−８０６７９号記載の化合物が好ましく用いられる。
【００７２】
本発明に係る熱現像感光材料には、現像を抑制あるいは促進させ現像を制御するため、分光増感効率を向上させるため、現像前後の保存性を向上させるため等にメルカプト化合物、ジスルフィド化合物、チオン化合物を含有させることができる。
【００７３】
本発明にメルカプト化合物を使用する場合、いかなる構造のものでも良いが、Ａｒ−ＳＭ、Ａｒ−Ｓ−Ｓ−Ａｒで表されるものが好ましい。式中、Ｍは水素原子またはアルカリ金属原子であり、Ａｒは１個以上の窒素、イオウ、酸素、セレニウムまたはテルリウム原子を有する芳香環または縮合芳香環を表す。
【００７４】
該芳香環としては、芳香族炭素環及び複素芳香族環が用いられるが、本発明においては複素芳香族環が好ましく用いられる。複素芳香族環としては、例えばベンゾイミダゾール、ナフトイミダゾール、ベンゾチアゾール、ナフトチアゾール、ベンゾオキサゾール、ナフトオキサゾール、ベンゾセレナゾール、ベンゾテルラゾール、イミダゾール、オキサゾール、ピラゾール、トリアゾール、チアジアゾール、テトラゾール、トリアジン、ピリミジン、ピリダジン、ピラジン、ピリジン、プリン、キノリンまたはキナゾリノンである。この複素芳香族環は、例えば、ハロゲン原子（例えば、Ｂｒ及びＣｌ等）、ヒドロキシル基、アミノ基、カルボキシル基、アルキル基（例えば、１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）及びアルコキシ基（例えば、１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）からなる置換基群から選択されるものを有してもよい。メルカプト置換複素芳香族化合物としては、２−メルカプトベンゾイミダゾール、２−メルカプトベンゾオキサゾール、２−メルカプトベンゾチアゾール、２−メルカプト−５−メチルベンゾチアゾール、３−メルカプト−１，２，４−トリアゾール、２−メルカプトキノリン、８−メルカプトプリン、２，３，５，６−テトラクロロ−４−ピリジンチオール、４−ヒドロキシ−２−メルカプトピリミジン、２−メルカプト−４−フェニルオキサゾール等が挙げられるが、本発明はこれらに限定されない。
【００７５】
本発明に係る熱現像感光材料には、感光性層側にマット剤を含有することが好ましく、熱現像後の画像の傷つき防止のためには感光材料の表面にマット剤を配することが好ましく、そのマット剤を乳剤層側の全バインダーに対し、質量比で０．５〜３０％含有することが好ましい。
【００７６】
本発明に用いられるマット剤の材質は有機物及び無機物のいずれでもよい。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またはカドミウム、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、同第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。
【００７７】
マット剤の形状は、定形、不定形どちらでも良いが、好ましくは定形で、球形が好ましく用いられる。マット剤の大きさはマット剤の体積を球形に換算したときの直径で表される。本発明においてマット剤の粒径とはこの球形換算した直径のことを示すものとする。
【００７８】
本発明に用いられるマット剤は、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。
【００７９】
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
本発明に用いられるマット剤は任意の構成層中に含むことができるが、本発明の目的を達成するためには好ましくは感光性層以外の構成層であり、更に好ましくは支持体から見て最も外側の層である。
【００８０】
本発明に用いられ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。また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。
【００８１】
本発明に係る熱現像感光材料には、帯電性を改良するために金属酸化物及び／または導電性ポリマー等の導電性化合物を構成層中に含ませることができる。これらはいず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、感光性層と下引の間の層等に含まれる。
【００８２】
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。
【００８３】
本発明に係る熱現像感光材料に使用される各種の添加剤は、感光性層、非感光性層、またはその他の構成層のいずれに添加しても良い。本発明では上述した以外に例えば、界面活性剤、酸化防止剤、安定化剤、可塑剤、紫外線吸収剤、被覆助剤等を用いても良い。これらの添加剤及び上述したその他の添加剤はＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ Ｉｔｅｍ１７０２９（１９７８年６月、ｐ．９〜１５）に記載されている化合物を好ましく用いることができる。
【００８４】
本発明に係る熱現像感光材料では、好ましいバインダーは透明または半透明で、一般に無色であり、天然ポリマー合成樹脂やポリマー及びコポリマー、その他フィルムを形成する媒体、例えば：ゼラチン、アラビアゴム、ポリ（ビニルアルコール）、ヒドロキシエチルセルロース、セルロースアセテート、セルロースアセテートブチレート、ポリ（ビニルピロリドン）、カゼイン、デンプン、ポリ（アクリル酸）、ポリ（メチルメタクリル酸）、ポリ（塩化ビニル）、ポリ（メタクリル酸）、コポリ（スチレン−無水マレイン酸）、コポリ（スチレン−アクリロニトリル）、コポリ（スチレン−ブタジエン）、ポリ（ビニルアセタール）類（例えば、ポリ（ビニルホルマール）及びポリ（ビニルブチラール））、ポリ（エステル）類、ポリ（ウレタン）類、フェノキシ樹脂、ポリ（塩化ビニリデン）、ポリ（エポキシド）類、ポリ（カーボネート）類、ポリ（ビニルアセテート）、セルロースエステル類、ポリ（アミド）類がある。親水性でも非親水性でもよい。また感光材料の表面を保護したり擦り傷を防止するために、感光性層の外側に非感光性層を有することができる。これらの非感光性層に用いられるバインダーは感光性層に用いられるバインダーと同じ種類でも異なった種類でもよい。
【００８５】
本発明においては、熱現像の速度を速めるために感光性層のバインダー量が１．５〜１０ｇ／ｍ²が好ましく、更に好ましくは１．７〜８ｇ／ｍ²である。
【００８６】
本発明に係る熱現像感光材料で用いられる支持体は、熱現像処理後の画像の変形を防ぐためにプラスチックフィルム（例えば、ポリエチレンテレフタレート、ポリカーボネート、ポリイミド、ナイロン、セルローストリアセテート、ポリエチレンナフタレート）であることが好ましい。
【００８７】
その中でも好ましい支持体としては、ポリエチレンテレフタレート（以下ＰＥＴと略す）及びシンジオタクチック構造を有するスチレン系重合体を含むプラスチック（以下ＳＰＳと略す）の支持体が挙げられる。支持体の厚みとしては５０〜３００μｍ程度、好ましくは７０〜１８０μｍである。
【００８８】
また熱処理したプラスチック支持体を用いることもできる。採用するプラスチックとしては、前記のプラスチックが挙げられる。支持体の熱処理とはこれらの支持体を製膜後、感光性層が塗布されるまでの間に、支持体のガラス転移点より３０℃以上高い温度で、好ましくは３５℃以上高い温度で、更に好ましくは４０℃以上高い温度で加熱することがよい。
【００８９】
次に、本発明に用いられるプラスチックについて説明する。
ＰＥＴはポリエステルの成分が全てポリエチレンテレフタレートからなるものであるが、ポリエチレンテレフタレート以外に、酸成分としてテレフタル酸、ナフタレン−２，６−ジカルボン酸、イソフタル酸、ブチレンジカルボン酸、５−ナトリウムスルホイソフタル酸、アジピン酸等と、グリコール成分としてエチレングリコール、プロピレングリコール、ブタンジオール、シクロヘキサンジメタノール等との変性ポリエステル成分が全ポリエステルの１０モル％以下含まれたポリエステルであってもよい。
【００９０】
ＳＰＳは通常のポリスチレン（アタクチックポリスチレン）と異なり立体的に規則性を有したポリスチレンである。ＳＰＳの規則的な立体規則性構造部分をラセモ連鎖といい、２連鎖、３連鎖、５連鎖、あるいはそれ以上と規則的な部分がより多くあることが好ましく、本発明において、ラセモ連鎖は、２連鎖で８５％以上、３連鎖で７５％以上、５連鎖で５０％以上、それ以上の連鎖で３０％以上であることが好ましい。ＳＰＳの重合は特開平３−１３１８４３号明細書記載の方法に準じて行うことができる。
【００９１】
本発明に用いられる支持体の製膜方法及び下引製造方法は公知の方法を用いることができるが、好ましくは、特開平９−５００９４号の段落〔００３０〕〜〔００７０〕に記載された方法を用いることである。
【００９２】
本発明に係る熱現像感光材料は支持体上に少なくとも一層の感光性層を有している。支持体の上に感光性層のみを形成しても良いが、感光性層の上に少なくとも１層の非感光性層を形成することが好ましい。感光性層に通過する光の量または波長分布を制御するために感光性層と同じ側にフィルター染料層及び／または反対側にアンチハレーション染料層、いわゆるバッキング層を形成しても良いし、感光性層に染料または顔料を含ませても良い。用いられる染料としては所望の波長範囲で目的の吸収を有するものであればいかなる化合物でも良いが、例えば特開昭５９−６４８１号、特開昭５９−１８２４３６号、米国特許第４，２７１，２６３号、同第４，５９４，３１２号、欧州特許公開５３３，００８号、同６５２，４７３号、特開平２−２１６１４０号、同４−３４８３３９号、同７−１９１４３２号、同７−３０１８９０号等に記載の化合物が好ましく用いられる。
【００９３】
またこれらの非感光性層には前記のバインダーやマット剤を含有することが好ましく、更にポリシロキサン化合物やワックスや流動パラフィンのようなスベリ剤を含有してもよい。
【００９４】
感光性層は複数層にしても良く、また階調の調節のため感度を高感層／低感層または低感層／高感層にしても良い。
【００９５】
本発明に係る熱現像感光材料は、熱現像処理にて写真画像を形成するもので、還元可能な銀源（有機銀塩）、感光性ハロゲン化銀、還元剤及び必要に応じて銀の色調を抑制する色調剤を通常（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熱現像感光材料であることが好ましい。本発明に係る熱現像感光材料は常温で安定であるが、露光後高温（例えば、８０℃〜１４０℃）に加熱することで現像される。加熱することで有機銀塩（酸化剤として機能する）と還元剤との間の酸化還元反応を通じて現像銀を生成する。この酸化還元反応は露光で感光性ハロゲン化銀に発生した潜像の触媒作用によって促進される。露光領域中の有機銀塩の反応によって生成した現像銀は黒色画像を提供し、これは非露光領域と対照をなし、画像の形成がなされる。この反応過程は、外部から水等の処理液を供給することなしで進行する。
【００９６】
本発明に係る熱現像感光材料の詳細は、例えば米国特許第３，１５２，９０４号、同第３，４５７，０７５号、及びＤ．モーガン（Ｍｏｒｇａｎ）による「ドライシルバー写真材料（Ｄｒｙ Ｓｉｌｖｅｒ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｍａｔｅｒｉａｌ）」やＤ．モーガン（Ｍｏｒｇａｎ）とＢ．シェリー（Ｓｈｅｌｙ）による「熱によって処理される銀システム（Ｔｈｅｒｍａｌｌｙ Ｐｒｏｃｅｓｓｅｄ Ｓｉｌｖｅｒ Ｓｙｓｔｅｍｓ）」（イメージング・プロセッシーズ・アンド・マテリアルズ（Ｉｍａｇｉｎｇ Ｐｒｏｃｅｓｓｅｓ ａｎｄ Ｍａｔｅｒｉａｌｓ）Ｎｅｂｌｅｔｔｅ 第８版、スタージ（Ｓｔｕｒｇｅ）、Ｖ．ウォールワース（Ｗａｌｗｏｒｔｈ）、Ａ．シェップ（Ｓｈｅｐｐ）編集、第２頁、１９６９年）等に開示されている。その中でも本発明においては、感光材料を８０〜１４０℃で熱現像することで画像を形成させ、定着を行わないことが特徴である。そのため、未露光部に残った感光性ハロゲン化銀や有機銀塩は除去されずにそのまま感光材料中に残る。
【００９７】
本発明に係る熱現像感光材料の熱現像処理機としては、温風加熱方式、加熱ドラム方式等の種類があるが、本発明においては、加熱ドラム方式の熱現像処理機で熱現像されることが好ましい。加熱ドラムは金属製加熱ドラムであることが更に好ましく、熱伝導度が１０〜２１０Ｗ／（ｍ・Ｋ）、比熱が０．２〜１．２ｋＪ／（ｋｇ・Ｋ）、密度が２〜１０ｇ／ｃｍ³、厚さが０．１〜５０ｍｍの範囲を満たす金属製加熱ドラムであることが特に好ましい。
【００９８】
また、本発明に係る熱現像感光材料を熱現像するに当たっては、前記金属製加熱ドラムの表面にシリコンゴム層をコートした形態の加熱ドラムを有する熱現像処理機で熱現像されることが特に好ましく、表面にコートするシリコンゴム層としては熱伝導度が０．１〜１．０Ｗ／（ｍ・Ｋ）、比熱が１．０〜２．０ｋＪ／（ｋｇ・Ｋ）、密度が０．８〜２．０ｇ／ｃｍ³、厚さが０．０５〜５ｍｍの範囲を満たすことが最も好ましい。
【００９９】
本発明に係る熱現像感光材料は、熱現像処理した後の、４００ｎｍにおける支持体を含んだ感光材料の光学透過濃度が０．２以下であることが好ましく、０．０２〜０．２であることが更に好ましい。
【０１００】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されない。
【０１０１】
実施例１
（ハロゲン化銀乳剤Ａの調製）
水９００ｍｌにオセインゼラチン７．５ｇ及び臭化カリウム１０ｍｇを溶解して温度３５℃、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及びＫ₂〔Ｉｒ（ＮＯ）Ｃｌ₅〕塩を銀１モル当たり１×１０^-4モルを含む水溶液を、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。その後４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデンを添加しＮａＯＨでｐＨを５に調整して平均粒子サイズ０．０６μｍ、粒子サイズの変動係数１１％、〔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を行い、その後フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整した。更にチオ硫酸ナトリウム及び塩化金酸で最適に化学増感を施し、ハロゲン化銀乳剤Ａを得た。
【０１０２】
（有機脂肪酸Ｎａ溶液Ｂの調製）
コンビミックスＳＬ−１０型（特殊機化工業（株）製）を用い以下のように調製した。コンビミックスＳＬ−１０型の反応容器内で４７２５ｍｌ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。その際、アンカーミクサーの回転数を１００ｒｐｍ、２対のディスパーミクサーを互いに逆方向で１５００ｒｐｍに設定した。次に１．５ｍｏｌ／Ｌの水酸化ナトリウム水溶液５４０．２ｍｌを添加した。次に濃硝酸６．９ｍｌを加えた後、５５℃に冷却して３０分攪拌させて有機脂肪酸Ｎａ溶液Ｂを得た。
【０１０３】
（感光性有機銀塩分散物の調製）
工程１：ウェットケーキ状有機銀塩組成物の作製
上記の有機脂肪酸Ｎａ溶液Ｂの温度を５５℃に保ったまま、アンカーミクサーの回転数を１２０ｒｐｍ、ディスパーミクサーの回転数を２５００ｒｐｍに設定し、上記ハロゲン化銀乳剤Ａ３２．３ｇと純水４５０ｍｌを添加した。次にアンカーミクサーの回転数を１６５ｒｐｍ、ディスパーミクサーの回転数を５０００ｒｐｍに設定し、１ｍｏｌ／Ｌの硝酸銀溶液７８０ｍｌを２分間かけてディスパーミクサーの近傍に添加した。更にディスパーミクサーの回転数を４５００ｒｐｍに設定し、１０分間攪拌し有機銀塩分散物を得た。次いで、得られた有機銀塩分散物を６０Ｌの容器に移し、純水を加えて攪拌後、静置させて有機銀塩分散物を浮上分離させた。浮上分離後、下層の水層を除去することで水溶性塩類を除去した。この操作を４回繰り返し、脱塩を行った。その後、三脚懸垂式遠心分離機Ｈ−１２２型式ＢＳ−２０（株式会社コクサン製）を９３１０ｍ・ｓ^-2で運転し、含水率２６５％のウェットケーキ状組成物を得た。
【０１０４】
工程２：有機銀塩分散物の乾燥
前記ウェットケーキ状有機銀塩組成物を湿式・乾式整粒機コーミルＵ−２０型（（株）パウレック製）を用いて回転数４７５ｒｐｍで解砕・整粒を行い、粉末状有機銀塩組成物を得た。次いで、箱型通気式乾燥機（不二パウダル（株）製）を用いて、乾燥温度５３℃の送風で５２時間乾燥処理を行い、乾燥済粉体を得た。
【０１０５】
工程３：有機銀塩組成物の分散
上記有機銀塩組成物の乾燥済粉体を１２５ｇ、ポリビニルブチラール（平均分子量４０００）３．６ｇ、メチルエチルケトン３６３ｇをディスパーで攪拌しながら混合した。次いで、横型ビーズミルＬＭＫ−４（株式会社アシザワ製、ビーズ：ジルコニア製）を用いて予備分散を行った後、周速１０ｍ／ｓで本分散を行い、感光性有機銀塩分散物を得た。
【０１０６】
〈ＰＥＴ下引済み写真用支持体の作製〉
市販の２軸延伸熱固定済みの厚さ１００μｍのＰＥＴフィルムの両面に８Ｗ／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０．８μｍになるように塗設し乾燥させて下引層Ａ−１とし、また反対側の面に下記帯電防止加工下引塗布液ｂ−１を乾燥膜厚０．８μｍになるように塗設し乾燥させて帯電防止加工下引層Ｂ−１とした。
【０１０７】
《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％） ２７０ｇ
（Ｃ−１） ０．６ｇ
ヘキサメチレン−１，６−ビス（エチレンウレア） ０．８ｇ
水で１Ｌに仕上げる
《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％） ２７０ｇ
（Ｃ−１） ０．６ｇ
ヘキサメチレン−１，６−ビス（エチレンウレア） ０．８ｇ
水で１Ｌに仕上げる
引き続き、下引層Ａ−１及び下引層Ｂ−１の上表面に、８Ｗ／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を乾燥膜厚０．１μｍになる様に下引上層Ａ−２として、下引層Ｂ−１の上には下記下引上層塗布液ｂ−２を乾燥膜厚０．８μｍになる様に帯電防止機能をもつ下引上層Ｂ−２として塗設した。
【０１０８】
《下引上層塗布液ａ−２》
ゼラチン ０．４ｇ／ｍ²になる質量
（Ｃ−１） ０．２ｇ
（Ｃ−２） ０．２ｇ
（Ｃ−３） ０．１ｇ
シリカ粒子（平均粒径３μｍ） ０．１ｇ
水で１Ｌに仕上げる
《下引上層塗布液ｂ−２》
（Ｃ−４） ６０ｇ
（Ｃ−５）を成分とするラテックス液（固形分２０％） ８０ｇ
硫酸アンモニウム ０．５ｇ
（Ｃ−６） １２ｇ
ポリエチレングリコール（平均分子量６００） ６ｇ
水で１Ｌに仕上げる
【０１０９】
【化４】

【０１１０】
【化５】

【０１１１】
（支持体の熱処理）
上記の下引済み支持体の下引乾燥工程において、支持体を１４０℃で加熱し、その後徐々に冷却した。
【０１１２】
〈熱現像感光材料の作製〉
前記ＰＥＴ下引済写真用支持体上に下記の各層を順次塗設し、試料１１を作製した。尚、乾燥は各々６０℃、１５分間で行った。
【０１１３】

【０１１４】
【化６】

【０１１５】
《感光層面塗布液》
以下の組成の塗布液を塗布銀量が２．１ｇ／ｍ²になる様に塗布した。
【０１１６】

【０１１７】
【化７】

【０１１８】
【化８】

【０１１９】

乾燥温度と乾燥時間を表１に示す条件に変更した以外は前記感光性有機銀塩分散物と同様にして感光性有機銀塩分散物を得、これを用いて試料１１と同様にして試料１２〜１８を作製した。
【０１２０】
（評価）
試料を３．５ｃｍ×１５ｃｍに断裁し、８１０ｎｍダイオードを備えたレーザー感光計で露光した後、１２０℃で１５秒間処理（現像）し、Ｄｍｉｎ及び最大画像濃度を評価し、表１に示した。最大画像濃度は試料１１の最大画像濃度を１００とする相対濃度で表す。
【０１２１】
【表１】

【０１２２】
表１より、本発明の試料は比較試料に比べ低カブリ、高画像濃度であることが明らかである。
【０１２３】
参考例１
この参考例においては乾燥時の風速条件を変化させて評価を行った。
【０１２４】
乾燥温度４０℃で風速を表２に示す条件に変更して行ったこと以外は実施例１と同様にして、試料２１〜２４を得た。
【０１２５】
（評価）
試料２１〜２４を３．５ｃｍ×１５ｃｍに断裁し、８１０ｎｍダイオードを備えたレーザー感光計で露光した後、１２０℃で１５秒間処理（現像）し、Ｄｍｉｎ及び最大画像濃度を評価し、表２に示した。最大画像濃度は試料２１の最大画像濃度を１００とする相対濃度で表す。
【０１２６】
【表２】

【０１２７】
表２より、試料２２〜２４は試料２１に比べ低カブリ、高画像濃度であることが明らかである。
【０１２８】
参考例２
この参考例においてはウェットケーキ状有機銀塩組成物の解砕後の粒子径を変化させて評価を行った。
【０１２９】
乾燥工程におけるウェットケーキ状有機銀塩組成物の解砕後の最大粒子径を表３に示す条件に変更して乾燥を行ったこと以外は上記参考例１の試料２４と同様にして、試料３１〜３４を得た。
【０１３０】
（評価）
試料３１〜３４を３．５ｃｍ×１５ｃｍに断裁し、８１０ｎｍダイオードを備えたレーザー感光計で露光した後、写真材料を１２０℃で１５秒間処理（現像）し、Ｄｍｉｎ及び最大画像濃度を評価し、表３に示した。最大画像濃度は試料３１の最大画像濃度を１００とする相対濃度で表す。
【０１３１】
【表３】

【０１３２】
表３より、試料３２〜３４は試料３１に比べ低カブリ、高画像濃度であることが明らかである。
【０１３３】
比較例３
この比較例においては乾燥済有機銀塩組成物粉末の含水率を変化させて評価を行った。
【０１３４】
有機銀塩組成物の含水率を表４に示す条件に変更して乾燥を行ったこと以外は上記比較例２の試料３４と同様にして、試料４１〜４４を得た。
【０１３５】
（評価）
試料４１〜４４を３．５ｃｍ×１５ｃｍに断裁し、８１０ｎｍダイオードを備えたレーザー感光計で露光した後、写真材料を１２０℃で１５秒間処理（現像）し、Ｄｍｉｎ及び最大画像濃度を評価し、表４に示した。最大画像濃度は試料４１の最大画像濃度を１００とする相対濃度で表す。
【０１３６】
【表４】

【０１３７】
表４より、試料４２〜４４は試料４１に比べ低カブリ、高画像濃度であることが明らかである。
【０１３８】
【発明の効果】
本発明により、低カブリ、高画像濃度、且つ、低コストな有機銀塩を含有する熱現像感光材料の製造方法を提供することができる。
【図面の簡単な説明】
【図１】本発明に用いられる流動層乾燥装置の一例を示す断面図である。
【符号の説明】
１ 給気風入口
２ 原料投入口
３ 乾燥室
４ バグフィルター
５ 排気口
６ 目皿板
７ 製品排出部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a photothermographic material containing an organic silver salt.
[0002]
[Prior art]
In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, there is a need for a technique relating to a photothermographic material for medical diagnosis and photographic technology that can be efficiently exposed by a laser imager or a laser image setter and can form an image having high resolution and sharpness. Has been. These photothermographic materials eliminate the use of solution processing chemicals and can provide customers with a simpler heat development processing system that does not damage the environment.
[0003]
As a photothermographic material, a black-and-white photothermographic material containing an organic silver salt called dry silver is well known. References include US Pat. No. 5,343,043 and Research Disclosure 17029. Can be mentioned.
[0004]
The photothermographic material is required to have many photographic performances, and low fog, maximum image density and the like are considered to be typical photographic performances. Many techniques aimed at improving fog characteristics, image density, and the like have been disclosed so far, but these techniques have not yet been sufficiently solved. One means for achieving a high image density is to increase the amount of coated silver, but there have been problems that cause fogging deterioration and cost increase. Therefore, there has been a demand for a technique that can obtain a high image density even when the amount of coated silver is reduced.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a photothermographic material containing an organic silver salt with low fog, high image density, and low cost.
[0006]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following means.
[0007]
  1. In the method for producing a photothermographic material containing an organic silver salt composition, the drying temperature in the drying step of the organic silver salt composition is38Less than ℃ and drying time32A method for producing a photothermographic material, characterized by being within a time.
[0008]
  2. Organic silver salt compositionThingThe wind speed of the drying process is 2 m / s or less.Said 1A method for producing a photothermographic material.
[0009]
  3. Drying process of organic silver salt compositionCrushed to a particle size of 10 mm or less1 aboveOr 2A method for producing the photothermographic material according to claim.
[0010]
  4). In the method for producing a photothermographic material containing an organic silver salt composition, the drying step of the organic silver salt compositionTo reduce the moisture content to 0.2% or lessIt is characterized byAny one of said 1-3.A method for producing a photothermographic material.
[0014]
Hereinafter, the present invention will be described in more detail.
A general process for producing a photothermographic material and terms used in the present invention will be briefly described. A preformed silver halide emulsion (B) and silver nitrate are added to an alkali solution of an organic fatty acid (A) such as behenic acid to prepare an organic silver salt dispersion (C). Water is added to (C) and stirred. After standing, the floated material is separated and desalted. Repeat this several times if necessary. Thereafter, it is dehydrated with a centrifugal separator or the like to obtain a slurry-like or wet cake-like organic silver salt composition (D). (D) is dried to obtain a dried organic silver salt composition or a dried powder (E). A binder and an organic solvent are added to (E) and stirred to obtain a photosensitive organic silver salt dispersion (F). Various additives such as a sensitizing dye, a reducing agent, an antifoggant, and a color toning agent are added to (F), and after applying the solution, it is applied and dried on a support to obtain a photothermographic material (G). In the present invention, among the above steps, the crushing / sizing step and the drying step are related.
[0015]
A method for producing the photothermographic material used in the present invention will be described. In the present invention, low-fogging, high image density, and low-cost organic silver is obtained by using a production method for drying an organic silver salt composition in a specific dry atmosphere and / or in a specific organic silver salt particle state. A photothermographic material containing a salt composition can be provided.
[0016]
However, in the known methods for producing an organic silver salt composition of a photothermographic material, no sufficient technique for solving a drying process that satisfies the desired performance of the photothermographic material has been recognized. U.S. Pat. No. 5,434,043 describes a drying process for a photothermographic material, but it has not yet achieved the desired performance of the photothermographic material.
[0017]
As a result of intensive studies by the present inventors, in the drying process of the organic silver salt composition, the organic silver salt composition is dried in a specific drying atmosphere and / or in a specific organic silver salt particle state. By using the production method to be carried out, it was possible to achieve improvement in photographic performance and cost reduction of the photothermographic material.
[0018]
  In the invention which concerns on Claim 1, the drying temperature of the drying process of an organic silver salt composition is38Below ℃, and32Within hours. FurtherIn the invention according to claim 1, there is no particularly limited dryer, and any device can be used. For example, a vacuum dryer, a freeze dryer, a box-type aeration / parallel flow dryer, an air flow A type dryer, a spray dryer, etc. can be used.
[0019]
In the invention which concerns on Claim 2, the wind speed of the drying process of an organic silver salt composition is 2 m / s or less. Preferably it is 1.5 m / s or less, More preferably, it is 1.0 m / s. Further, in the invention according to claim 2, any convection heat transfer type dryer can be used without any particular limitation. For example, a band parallel flow dryer, a box-type aeration / parallel flow dryer, a multistage disk A type dryer, a flash dryer, a fluidized bed dryer, or the like can be used. In particular, a fluidized bed dryer is preferably used.
[0020]
  Claim3In the invention according to the present invention, the organic silver salt composition before being dried has a particle size of 10 mm or less, preferably 7 mm or less, and more preferably 4 mm or less.
[0021]
  Claim4In the invention according to the present invention, the water content after drying of the organic silver salt composition is 0.2% or less, preferably 0.15% or less, and more preferably 0.1% or less.
[0022]
There is no limitation in particular as a crushing apparatus applied to the organic silver salt composition used for this invention, All apparatuses can be used. Examples of the crushing apparatus used in the present invention include a rolling mill, a vibration mill, a roller mill, and an impact mill. In particular, an impact mill is preferably used.
[0023]
An example of a fluidized bed dryer preferably used in the present invention is shown in FIG. Drying may be performed twice or more from the viewpoint of productivity and prevention of overdrying. Moreover, you may change a drying temperature and a wind speed arbitrarily with the state of the organic silver salt composition at the time of drying.
[0024]
An example of the fluidized bed dryer used in the present invention will be described with reference to FIG. In the figure, 1 is a supply air inlet, and 2 is a raw material inlet. A supply air controlled to a preset temperature is blown from a supply air inlet 1 using a fan (not shown). The supply air passes through the drying chamber 3 and the bag filter 4 and is then discharged from the exhaust port 5. The organic silver salt composition in the form of a slurry or wet cake containing the organic silver salt is charged into the drying chamber 3 from the raw material charging port 2, and is stirred and fluidized in the drying chamber 3 by the air supplied from the pan plate 6. Dried. At that time, fine powder generated during the drying is captured by the bag filter 4, and is removed by mechanical vibration and / or an appropriate pulse jet such as air or nitrogen and re-dried. Further, the air supply air and the drying temperature can be changed at any time during the drying due to the change in the state of the organic silver composition at the time of drying. After the drying is completed, the dry powder is collected from the product discharge unit 7.
[0025]
As a specific apparatus meeting the object of the present invention, there is a slit flow manufactured by Okawara Manufacturing Co., Ltd.
[0026]
There are no particular limitations on the dispersion apparatus applied to the dispersion of the dried organic silver composition used in the present invention, and any apparatus can be used, including a high-pressure homogenizer, an ultrasonic disperser, and a media disperser. In particular, a media disperser is preferably used.
[0027]
Preparation of a coating solution containing an organic silver salt composition used in the present invention means that various additives such as a reducing agent, an antifoggant, and a color to be described later are added to an organic silver salt dispersion at a desired pH and temperature. It is a process of adding and aging while controlling.
[0028]
The organic silver salt according to the present invention is a reducible silver source and is an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include aliphatic carboxylic acids, carbocyclic carboxylic acids, heterocyclic carboxylic acids, heterocyclic compounds, etc., but particularly long chains (10-30, preferably 15-25). The aliphatic carboxylic acid having the number of carbon atoms) and the heterocyclic carboxylic acid having a nitrogen-containing heterocyclic ring are preferably used. An organic silver salt complex having a total stability constant with respect to silver ions having a ligand of 4.0 to 10.0 is also useful.
[0029]
Examples of organic silver salts according to the present invention are described in Research Disclosure Nos. 17029 and 29963, and include the following: silver salts of fatty acids (eg, gallic acid, oxalic acid, behenic acid, arachidic acid, stearin Acid, palmitic acid, silver salt such as lauric acid); silver carboxyalkylthiourea salt (for example, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc.) A silver complex of a polymerization reaction product of aldehyde and hydroxy-substituted aromatic carboxylic acid (for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted aromatic carboxylic acids (for example, salicylic acid, benzoic acid, 3, 5 -Dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc.) and Silver complexes or the like of polymerization reaction products; silver salts or complexes of thiones (eg, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline) 2-thione), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole Complexes or salts thereof; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptans. Among the organic silver salts described above, fatty acid silver salts are preferably used, and more preferably silver behenate, silver arachidate, and silver stearate.
[0030]
The shape of the organic silver salt according to the present invention is not particularly limited, but a disc or oval flat plate crystal, a needle crystal having a minor axis and a major axis, or a mixture thereof is preferable. Among these, it is more preferable that a large number of disks or oval flat plate crystals occupy.
[0031]
The organic silver salt is preferably finely dispersed, and preferably has an average particle size of 0.03 to 1.0 μm, more preferably 0.05 to 0.8 μm. The organic silver salt is preferably dispersed uniformly. Specifically, the volume average particle size of 60% by mass or more of the organic silver salt is preferably 0.8 μm or less, and the volume average particle size of 75% by mass or more is more preferably 0.8 μm or less, Most preferably, the volume average particle size of 90% by mass or more is 0.8 μm or less. As a measuring method of the average particle size and the volume average particle size, it is preferable to use a particle size distribution meter, for example, a laser diffraction type particle size distribution measuring device (manufactured by Nippon Laser Co., Ltd.). It is calculated by irradiating light and obtaining an autocorrelation function with respect to temporal change of fluctuation of the scattered light.
[0032]
The dispersion of the organic silver salt according to the present invention can be obtained by mixing silver nitrate and an organic acid alkali metal salt, and is produced using a mixing method in which photosensitive silver halide and then silver nitrate are added at the time of forming the organic silver salt. It is preferable.
[0033]
For example, an alkali metal hydroxide (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 halogenated. An organic silver salt dispersion used in the present invention can be prepared by adding silver and then adding and mixing silver nitrate. Furthermore, it is also one of the preferable embodiments that the organic silver salt dispersion used in the present invention is prepared by using a so-called controlled triple jet method in which an alkali metal salt of organic acid, silver nitrate and silver halide are simultaneously added and mixed. One.
[0034]
The photosensitive silver halide grains used in the present invention function as an optical sensor. In the present invention, the average particle size is preferably 0.1 μm or less, more preferably 0.01 to 0.1 μm, and most preferably 0.02 to 0.08 μm.
[0035]
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. In the case of non-normal crystals, for example, in the case of spherical, rod-like, or tabular grains, the diameter when considering a sphere equivalent to the volume of silver halide grains is shown.
[0036]
The photosensitive silver halide grains are preferably monodispersed. The monodispersion here refers to a case where the monodispersity obtained by the following formula is 40% or less. In the present invention, the monodispersity is more preferably 30% or less, and particularly preferably 0.1 to 20%.
[0037]
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100
The shape of the photosensitive silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, further 70% or more, and particularly 80% or more. It is preferable. The ratio of the Miller index [100] plane was determined by T.T. Tani, J .; Imaging Sci. 29, 165 (1985).
[0038]
Another preferred form of photosensitive silver halide is tabular grain. The tabular grains referred to here are those having an aspect ratio = r / h of 3 or more when the square root of the projected area is the grain size r μm and the thickness in the vertical direction is h μm. Among them, the aspect ratio is more preferably 3 to 50. The particle size is preferably 0.1 μm or less, more preferably 0.01 to 0.08 μm. These are described in U.S. Pat. Nos. 5,264,337, 5,314,798, 5,320,958, etc., and the desired tabular grains can be obtained with reference to the above patents. Can do.
[0039]
The halogen composition of the photosensitive silver halide grains is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.
[0040]
The photosensitive silver halide grains used in the present invention can be prepared by any method well known in the art. Grafkides, Chimie et Physique Photographic (published by Paul Montel, 1967), G.K. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. Many documents can be referred to, such as Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al.
[0041]
The photosensitive silver halide used in the present invention preferably contains a metal ion belonging to Groups 6 to 11 of the periodic table. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable.
[0042]
These metal ions can be introduced into the silver halide in the form of metal complexes or metal complex ions. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.
[0043]
General formula [ML₆]^m
In the formula, M represents a transition metal selected from Group 6 to 11 elements of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), 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.
[0044]
Specific preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).
[0045]
Although the specific example of the transition metal complex ion used by this invention is shown below, this invention is not limited to these.
[0046]
1: [RhCl₆]^3-
2: [RuCl₆]^3-
3: [ReCl₆]^3-
4: [RuBr₆]^3-
5: [OsCl₆]^3-
6: [IrCl₆]^Four-
7: [Ru (NO) Cl_Five]^2-
8: [RuBr_Four(H₂O)]^2-
9: [Ru (NO) (H₂O) Cl_Four]^-
10: [RhCl_Five(H₂O)]^2-
11: [Re (NO) Cl_Five]^2-
12: [Re (NO) (CN)_Five]^2-
13: [Re (NO) Cl (CN)_Four]^2-
14: [Rh (NO)₂Cl_Four]^-
15: [Rh (NO) (H₂O) Cl_Four]^-
16: [Ru (NO) (CN)_Five]^2-
17: [Fe (CN)₆]^3-
18: [Rh (NS) Cl_Five]^2-
19: [Os (NO) Cl_Five]^2-
20: [Cr (NO) Cl_Five]^2-
21: [Re (NO) Cl_Five]^-
22: [Os (NS) Cl_Four(TeCN)]^2-
23: [Ru (NS) Cl_Five]^2-
24: [Re (NS) Cl_Four(SeCN)]^2-
25: [Os (NS) Cl (SCN)_Four]^2-
26: [Ir (NO) Cl_Five]^2-
27: [Ir (NS) Cl_Five]^2-
One kind of these metal ions, metal complexes or metal complex ions may be used, or two or more kinds of the same and different metals may be used in combination. The content of these metal ions, metal complexes or metal complex ions is generally 1 × 10 5 per mole of silver halide.^-9~ 1x10^-2Molar is suitable, preferably 1 × 10^-8~ 1x10^-FourIs a mole.
[0047]
The compounds providing these metals 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, chemical sensitization It may be added at any stage before or after, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably at the stage of nucleation. Add in stages.
[0048]
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. Preferably, a distribution can be provided inside the particles.
[0049]
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 the water-soluble silver salt solution or 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 which 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.
[0050]
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 physical ripening, or at the time of chemical ripening.
[0051]
The photosensitive silver halide grains used in the present invention are preferably desalted after grain formation. When desalting is performed, the noodle method, flocculation method, ultrafiltration method, etc. are known in the art. It can desalinate by washing with water using the method.
[0052]
The photosensitive silver halide grains used in the present invention are preferably chemically sensitized. As a preferable chemical sensitization method, a sulfur sensitization method, a selenium sensitization method and a tellurium sensitization method can be used as is well known in the art. Further, noble metal sensitization methods such as gold compounds, platinum, palladium, iridium compounds and reduction sensitization methods can be used. As the compound preferably used in the sulfur sensitization method, selenium sensitization method, and tellurium sensitization method, known compounds can be used, but compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te. A compound having a bond, tellurocarboxylic acid salts, Te-organyltellurocarboxylic acid esters, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium and the like can be used. Compounds preferably used for the noble metal sensitization include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent 618,061, etc. Can preferably be used.
[0053]
As specific compounds of the reduction sensitization method, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. can be used in addition to ascorbic acid and thiourea dioxide. . Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH at 7 or higher or the pAg at 8.3 or lower. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.
[0054]
In the present invention, the amount of the photosensitive silver halide relative to the organic silver salt is preferably 0.01 to 0.30 mol of the photosensitive silver halide (as silver) with respect to 1 mol of the organic silver salt (as silver). 0.01 to 0.20 mol is more preferable, and 0.02 to 0.15 mol is particularly preferable.
[0055]
As described above, the photosensitive silver halide contained in the photothermographic material according to the present invention is preferably prepared separately from the organic silver salt. About the mixing method of both, the photosensitive silver halide grains and the organic silver salt prepared separately are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer or the like, or the preparation of the organic silver salt There is a method of preparing an organic silver salt by mixing photosensitive silver halide preliminarily prepared at any of the above timings, but there is no particular limitation as long as the effects of the present invention are sufficiently exhibited.
[0056]
The photothermographic material according to the invention preferably contains a reducing agent. Examples of preferred reducing agents are described in US Pat. Nos. 3,770,448, 3,773,512, 3,593,863, and Research Disclosure Nos. 17029 and 29963. There is something. Aminohydroxycycloalkenone compounds (eg, 2-hydroxypiperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents; N— Hydroxyurea derivatives (eg Np-methylphenyl-N-hydroxyurea); aldehyde or ketone hydrazones (eg anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (Eg hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5-dihydroxy-phenyl) methylsulfone); sulfohydroxamic acids (eg benzenesulfohydroxam ); Sulfonamidoanilines (eg, 4- (N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (eg, 2-methyl-5- (1-phenyl-5-tetrazolylthio) hydroquinone); tetrahydro Quinoxalines (eg, 1,2,3,4-tetrahydroquinoxaline); amidooximes (eg, phenylamidooxime, 2-thienyl-amidooxime, p-phenoxy-phenylamidoxime, etc.); azines (eg, aliphatic carbon Acid hydrazides and ascorbic acid); polyhydroxybenzene and hydroxylamine combinations; reductone and / or hydrazine; hydroxamic acids; azines and sulfonamidophenols; α-cyanophenylacetic acid derivatives Conductor; combination of bis-β-naphthol and 1,3-dihydroxybenzene derivative; 5-pyrazolone; sulfonamide phenol reducing agent; 2-phenylindane-1,3-dione and the like; chroman; 1,4-dihydropyridines ( For example, 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine); bisphenols (eg, bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, bis (6 -Hydroxy-m-tri) mesitol, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,5-ethylidene-bis (2-tert-butyl-6-methyl) phenol), UV-sensitive ascorbic acid derivatives and 3-pyrazolidones. Of these, particularly preferred reducing agents are hindered phenols. Examples of the hindered phenols include compounds represented by the following general formula (A).
[0057]
[Chemical 1]

[0058]
In the formula, R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (for example, a butyl group, 2,4,4-trimethylpentyl group, etc.), and R ′ and R ″ have 1 to 5 carbon atoms. An alkyl group (for example, a methyl group, an ethyl group, a t-butyl group, etc.) is represented.
[0059]
Specific examples of the compound represented by formula (A) are shown below. However, the present invention is not limited to these.
[0060]
[Chemical 2]

[0061]
[Chemical 3]

[0062]
In the present invention, the amount of the reducing agent including the compound represented by the general formula (A) is preferably 1.0 × 10 6 per silver mole.^-2-10 mol, more preferably 1.0 x 10^-2~ 3 moles.
[0063]
The photothermographic material according to the invention may contain an antifoggant. Known as an antifoggant is mercury ion, and the use of a mercury compound as an antifoggant in a light-sensitive material is disclosed in, for example, US Pat. No. 3,589,903. However, since mercury compounds are environmentally unfavorable, non-mercury fog prevention as disclosed in, for example, US Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234 An agent is preferably used in the present invention.
[0064]
Particularly preferred non-mercury antifoggants include compounds such as those disclosed in US Pat. Nos. 3,874,946 and 4,756,999, —C (X₁) (X₂) (X_Three) (Where X₁And X₂Represents a halogen atom and X_ThreeRepresents a hydrogen or halogen atom), and a heterocyclic compound having one or more substituents represented by.
[0065]
Other suitable antifoggants include compounds described in paragraphs [0030] to [0036] of JP-A-9-288328 and paragraphs [0062] to [0063 of JP-A-9-90550. And the compounds disclosed in US Pat. No. 5,028,523 and European Patent Nos. 600,587, 605,981, 631,176, etc. I can do it.
[0066]
In the present invention, the amount of antifoggant, including non-mercury antifoggant, is preferably 1.0 × 10 6 per mole of silver.^-Four-10 mol, more preferably 1.0 x 10^-3~ 1.5 mol.
[0067]
To the photothermographic material according to the invention, it is preferable to add a color toning agent for the purpose of improving the silver tone after development. Examples of preferred toning agents are disclosed in Research Disclosure No. 17029 and include:
[0068]
Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline, and 2,4- Thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3-mercapto-1,2,4-triazole) N- (aminomethyl) aryl dicarboximides (eg N- (dimethylaminomethyl) phthalimide); blocked pyrazoles (eg N, N′-hexamethylene (1-carbamoyl-3,5-dimethyl); Pyrazole)), isothiuronium (is thiuronium) derivatives and certain photobleaching combinations, (combination of 1,8- (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole) Phthalazinone, phthalazinone derivatives or metal salts of these derivatives (eg, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3-dihydro-1,4 -Phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (eg 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); a combination of phthalazine + phthalic acid; Addition of phthalazine And maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) A quinazolinedione, a benzoxazine, a naltoxazine derivative; a benzoxazine-2,4-dione (eg, 1,3-benzoxazine-2,4-dione); Pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5, 6a-tetraazapentalene). Preferred toning agents are phthalazinone or phthalazine.
[0069]
In the present invention, the amount of the toning agent including phthalazone or phthalazine is preferably 1.0 × 10 6 per silver mole.^-3-10 mol, more preferably 1.0 x 10^-2~ 5 moles.
[0070]
Examples of the photothermographic material according to the invention include 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. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, 4,835,096 Sensitizing dyes can be used.
[0071]
Useful sensitizing dyes preferably used in the present invention are described in, for example, the literature described or cited in Research Disclosure Item 17643IV-A (December 1978, p.23), Item 18431 (August 1979, p.437). Are listed. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, compounds described in JP-A Nos. 9-34078, 9-54409, and 9-80679 are preferably used.
[0072]
The photothermographic material according to the present invention includes a mercapto compound, a disulfide compound, and a thione to suppress or promote development and control development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. Compounds can be included.
[0073]
When a mercapto compound is used in the present invention, any structure may be used, but those represented by Ar-SM and Ar-SS-Ar are preferred. In the formula, M represents a hydrogen atom or an alkali metal atom, and Ar represents an aromatic ring or condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms.
[0074]
As the aromatic ring, an aromatic carbocycle and a heteroaromatic ring are used. In the present invention, a heteroaromatic ring is preferably used. Examples of the heteroaromatic ring include benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, Pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. This heteroaromatic ring is, for example, a halogen atom (for example, Br and Cl), a hydroxyl group, an amino group, a carboxyl group, an alkyl group (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms) And a group selected from a substituent group consisting of an alkoxy group (for example, one having one or more carbon atoms, preferably 1 to 4 carbon atoms). Mercapto-substituted heteroaromatic compounds include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzothiazole, 3-mercapto-1,2,4-triazole, 2 -Mercaptoquinoline, 8-mercaptopurine, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-hydroxy-2-mercaptopyrimidine, 2-mercapto-4-phenyloxazole, and the like. Is not limited to these.
[0075]
The photothermographic material according to the present invention preferably contains a matting agent on the photosensitive layer side, and it is preferable to dispose the matting agent on the surface of the photosensitive material in order to prevent damage to the image after heat development. The matting agent is preferably contained in a mass ratio of 0.5 to 30% with respect to the total binder on the emulsion layer side.
[0076]
The material of the matting agent used in the present invention 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, etc., polyacrylonitrile described in US Pat. No. 3,079,257, No. 3,022,169 etc. An organic matting agent such as polycarbonate can be used.
[0077]
The shape of the matting agent may be either a regular shape or an irregular shape, but is preferably a regular shape, and a spherical shape is preferably used. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle size of the matting agent indicates the diameter converted into a spherical shape.
[0078]
The matting agent used in the present invention 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.
[0079]
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 matting agent used in the present invention can be contained in any constituent layer, but in order to achieve the object of the present invention, it is preferably a constituent layer other than the photosensitive layer, and more preferably viewed from the support. The outermost layer.
[0080]
The method for adding the matting agent used in 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. It may be used. When a plurality of types of matting agents are added, both methods may be used in combination.
[0081]
In the photothermographic material according to the invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained 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, and the like.
[0082]
In the present invention, the conductive compounds described in US Pat. No. 5,244,773 and columns 14 to 20 are preferably used.
[0083]
Various additives used in the photothermographic material according to the invention may be added to any of the photosensitive layer, the non-photosensitive layer, and other constituent layers. In the present invention, for example, surfactants, antioxidants, stabilizers, plasticizers, ultraviolet absorbers, coating aids and the like may be used in addition to those described above. As these additives and the other additives described above, compounds described in Research Disclosure Item 17029 (June 1978, pp. 9-15) can be preferably used.
[0084]
In the photothermographic material according to the present invention, preferred binders are transparent or translucent and generally colorless, and natural polymer synthetic resins, polymers and copolymers, and other media for 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 ( Urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. It may be hydrophilic or non-hydrophilic. Further, in order to protect the surface of the photosensitive material and prevent scratches, a non-photosensitive layer can be provided outside the photosensitive layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the photosensitive layer.
[0085]
In the present invention, the binder amount of the photosensitive layer is 1.5 to 10 g / m in order to increase the speed of heat development.²Is more preferable, and 1.7 to 8 g / m is more preferable.²It is.
[0086]
The support used in the photothermographic material according to the present invention is a plastic film (for example, polyethylene terephthalate, polycarbonate, polyimide, nylon, cellulose triacetate, polyethylene naphthalate) in order to prevent deformation of the image after heat development. Is preferred.
[0087]
Among them, preferable supports include polyethylene terephthalate (hereinafter abbreviated as PET) and a plastic (hereinafter abbreviated as SPS) support including a styrene polymer having a syndiotactic structure. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.
[0088]
A heat-treated plastic support can also be used. Examples of the plastic to be used include the plastics described above. The heat treatment of the support is a temperature higher than the glass transition point of the support by 30 ° C. or more, preferably 35 ° C. or more, after these supports are formed and before the photosensitive layer is applied, More preferably, heating is performed at a temperature higher by 40 ° C. or more.
[0089]
Next, the plastic used in the present invention will be described.
PET is composed of polyethylene terephthalate as a component of polyester. However, in addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid, 5-sodium sulfoisophthalic acid, It may be a polyester in which a modified polyester component such as adipic acid or the like and ethylene glycol, propylene glycol, butanediol, cyclohexanedimethanol or the like as a glycol component is contained in an amount of 10 mol% or less of the total polyester.
[0090]
Unlike ordinary polystyrene (atactic polystyrene), SPS is a polystyrene having three-dimensional regularity. The regular stereoregular structure portion of SPS is called a racemo chain, and it is preferable that there are more regular portions such as a 2-chain, 3-chain, 5-chain or more. In the present invention, the racemo-chain is 2 It is preferably 85% or more in the chain, 75% or more in the 3 chain, 50% or more in the 5 chain, and 30% or more in the further chain. The polymerization of SPS can be carried out according to the method described in JP-A No. 3-131843.
[0091]
A known method can be used for the film-forming method and the undercoating method for the support used in the present invention. Preferably, the methods described in paragraphs [0030] to [0070] of JP-A-9-50094 are used. Is to use.
[0092]
The photothermographic material according to the 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. In order to control the amount of light passing through the photosensitive layer or the wavelength distribution, a filter dye layer on the same side as the photosensitive layer and / or an antihalation dye layer on the opposite side, a so-called backing layer may be formed. A dye or pigment may be included in the conductive layer. Any dye may be used as long as it has the desired absorption in a desired wavelength range. For example, JP-A-59-6481, JP-A-59-182436, US Pat. No. 4,271,263. No. 4,594,312, European Patent Publications 533,008, 652,473, JP-A-2-216140, No. 4-348339, No. 7-191432, No. 7-301890, etc. Are preferably used.
[0093]
These non-photosensitive layers preferably contain the binder and matting agent, and may further contain a polysiloxane compound, a sliding agent such as wax or liquid paraffin.
[0094]
The photosensitive layer may be composed of a plurality of layers, and the sensitivity may be a high sensitivity layer / a low sensitivity layer or a low sensitivity layer / a high sensitivity layer for gradation adjustment.
[0095]
The photothermographic material according to the present invention forms a photographic image by heat development, and includes a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent, and, if necessary, the color tone of silver. It is preferable that the photothermographic material contains a toning agent that suppresses the above in a state where it is dispersed in a normal (organic) binder matrix. The photothermographic material according to the invention is stable at room temperature, but is developed by heating to a high temperature (for example, 80 ° C. to 140 ° C.) after exposure. By heating, developed silver is generated through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This redox reaction is promoted by the catalytic action of the latent image generated on the photosensitive silver halide upon exposure. The developed silver produced by the reaction of the organic silver salt in the exposed areas provides a black image that contrasts with the unexposed areas and forms an image. This reaction process proceeds without supplying a treatment liquid such as water from the outside.
[0096]
Details of the photothermographic material according to the present invention are described in, for example, U.S. Pat. Nos. 3,152,904, 3,457,075, and D.I. “Dry Silver Photographic Material” by Morgan, D.M. Morgan and B.M. "Thermally Processed Silver Systems" by Shely (Imaging Processes and Materials) Nebelte 8th Edition, Sturges. (Walworth), A. Shepp (2nd page, 1969), and the like. Among them, the present invention is characterized in that an image is formed by thermally developing a photosensitive material at 80 to 140 ° C. and fixing is not performed. Therefore, the photosensitive silver halide and organic silver salt remaining in the unexposed area remain in the photosensitive material as they are without being removed.
[0097]
There are various types of photothermographic processing machines for photothermographic materials according to the present invention, such as a hot air heating method and a heating drum method. Is preferred. The heating drum is more preferably a metal heating drum, with a thermal conductivity of 10 to 210 W / (m · K), a specific heat of 0.2 to 1.2 kJ / (kg · K), and a density of 2 to 10 g / cm^ThreeA metal heating drum satisfying a thickness range of 0.1 to 50 mm is particularly preferable.
[0098]
Further, when the photothermographic material according to the present invention is heat-developed, it is particularly preferable that the photothermographic material is heat-developed with a heat-development processor having a heating drum in a form in which a silicon rubber layer is coated on the surface of the metal heating drum. The silicon rubber layer coated on the surface has a thermal conductivity of 0.1 to 1.0 W / (m · K), a specific heat of 1.0 to 2.0 kJ / (kg · K), and a density of 0.8 to 2.0 g / cm^ThreeMost preferably, the thickness satisfies the range of 0.05 to 5 mm.
[0099]
In the photothermographic material according to the invention, the optical transmission density of the photosensitive material containing a support at 400 nm after heat development is preferably 0.2 or less, and is 0.02 to 0.2. More preferably.
[0100]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.
[0101]
Example 1
(Preparation of silver halide emulsion A)
After dissolving 7.5 g of ossein gelatin and 10 mg of potassium bromide in 900 ml of water and adjusting the temperature to 35 ° C. and pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate and an odor with a molar ratio of (98/2) Potassium iodide and potassium iodide and K₂[Ir (NO) Cl_Five] 1 x 10 salt per mole of silver^-FourAn aqueous solution containing a mole was added over 10 minutes by the controlled double jet method while maintaining pAg of 7.7. Then 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added and the pH was adjusted to 5 with NaOH to obtain an average particle size of 0.06 μm, a particle size variation coefficient of 11%, [100] Cubic silver iodobromide grains having an area ratio of 87% were obtained. The emulsion was coagulated and precipitated using a gelatin flocculant and desalted, and then 0.1 g phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5. Further, chemical sensitization was optimally performed with sodium thiosulfate and chloroauric acid to obtain silver halide emulsion A.
[0102]
(Preparation of organic fatty acid Na solution B)
It was prepared as follows using Combimix SL-10 type (manufactured by Tokushu Kika Kogyo Co., Ltd.). In a Combimix SL-10 type reaction vessel, 111.4 g of behenic acid, 83.8 g of arachidic acid, and 54.9 g of stearic acid were dissolved in 4725 ml of pure water at 80 ° C. At that time, the rotation speed of the anchor mixer was set to 100 rpm, and the two pairs of disperser were set to 1500 rpm in opposite directions. Next, 540.2 ml of 1.5 mol / L sodium hydroxide aqueous solution was added. Next, after adding 6.9 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain an organic fatty acid Na solution B.
[0103]
(Preparation of photosensitive organic silver salt dispersion)
Step 1: Preparation of wet cake-like organic silver salt composition
While maintaining the temperature of the organic fatty acid Na solution B at 55 ° C., the rotation speed of the anchor mixer is set to 120 rpm, the rotation speed of the disperser is set to 2500 rpm, and 32.3 g of the silver halide emulsion A and 450 ml of pure water are added. did. Next, the rotation speed of the anchor mixer was set to 165 rpm, the rotation speed of the disperser was set to 5000 rpm, and 780 ml of a 1 mol / L silver nitrate solution was added to the vicinity of the disperser over 2 minutes. Further, the rotational speed of the dispermixer was set to 4500 rpm, and the mixture was stirred for 10 minutes to obtain an organic silver salt dispersion. Next, the obtained organic silver salt dispersion was transferred to a 60 L container, pure water was added and stirred, and then allowed to stand to float and separate the organic silver salt dispersion. After the floating separation, the water-soluble salts were removed by removing the lower aqueous layer. This operation was repeated 4 times to perform desalting. Thereafter, a tripod suspension centrifuge H-122 type BS-20 (manufactured by Kokusan Co., Ltd.) was replaced with 9310 m · s.^-2The wet cake-like composition having a water content of 265% was obtained.
[0104]
Step 2: Drying the organic silver salt dispersion
The wet cake-like organic silver salt composition is pulverized and sized at a rotation speed of 475 rpm using a wet / dry granulator Comil U-20 type (manufactured by POWREC Co., Ltd.) to obtain a powdery organic silver salt composition Got. Next, using a box-type ventilating dryer (manufactured by Fuji Paudal Co., Ltd.), a drying process was performed for 52 hours by blowing air at a drying temperature of 53 ° C. to obtain a dried powder.
[0105]
Step 3: Dispersion of the organic silver salt composition
125 g of the dried powder of the organic silver salt composition, 3.6 g of polyvinyl butyral (average molecular weight 4000), and 363 g of methyl ethyl ketone were mixed with stirring with a disper. Subsequently, preliminary dispersion was performed using a horizontal bead mill LMK-4 (manufactured by Ashizawa Co., Ltd., beads: manufactured by Zirconia), followed by main dispersion at a peripheral speed of 10 m / s to obtain a photosensitive organic silver salt dispersion.
[0106]
<Preparation of PET undercoated photographic support>
8 W / m on both sides of a commercially available biaxially stretched PET film with a thickness of 100 μm²・ A corona discharge treatment was applied for one minute, and the following undercoat coating solution a-1 was applied on one surface to a dry film thickness of 0.8 μm and dried to form an undercoat layer A-1, and on the other side The surface was coated with the following antistatic processing subbing coating solution b-1 so as to have a dry film thickness of 0.8 μm and dried to obtain an antistatic processing subbing layer B-1.
[0107]
<< 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) copolymer latex liquid (solid content 30%) 270 g
(C-1) 0.6g
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1L with water
<< Undercoating liquid b-1 >>
Butyl acrylate (40% by mass), styrene (20% by mass),
Copolymer latex solution of glycidyl acrylate (40% by mass)
(Solid content 30%) 270 g
(C-1) 0.6g
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1L with water
Subsequently, 8 W / m on the upper surface of the undercoat layer A-1 and the undercoat layer B-1.²・ Corona discharge was applied for a minute, and on the undercoat layer A-1, the following undercoat upper layer coating solution a-2 was used as the undercoat upper layer A-2 so as to have a dry film thickness of 0.1 μm. The following undercoat upper layer coating solution b-2 was coated on B-1 as an undercoat upper layer B-2 having an antistatic function so as to have a dry film thickness of 0.8 μm.
[0108]
<< Undercoating upper layer coating liquid a-2 >>
Gelatin 0.4g / m²Mass to become
(C-1) 0.2g
(C-2) 0.2g
(C-3) 0.1 g
Silica particles (average particle size 3μm) 0.1g
Finish to 1L with water
<< Undercoating Upper Layer Coating Liquid b-2 >>
(C-4) 60g
Latex liquid containing 20% of (C-5) (solid content 20%) 80g
Ammonium sulfate 0.5g
(C-6) 12g
Polyethylene glycol (average molecular weight 600) 6g
Finish to 1L with water
[0109]
[Formula 4]

[0110]
[Chemical formula 5]

[0111]
(Heat treatment of support)
In the undercoating drying process of the above-described undercoated support, the support was heated at 140 ° C. and then gradually cooled.
[0112]
<Preparation of photothermographic material>
Samples 11 were prepared by sequentially coating the following layers on the PET underdrawn photographic support. The drying was performed at 60 ° C. for 15 minutes.
[0113]

[0114]
[Chemical 6]

[0115]
<< Photosensitive surface coating solution >>
A coating solution having the following composition has a coating silver amount of 2.1 g / m.²It applied so that it might become.
[0116]

[0117]
[Chemical 7]

[0118]
[Chemical 8]

[0119]

A photosensitive organic silver salt dispersion was obtained in the same manner as the photosensitive organic silver salt dispersion except that the drying temperature and the drying time were changed to the conditions shown in Table 1. Sample 12 was used in the same manner as Sample 11 using this. -18 were produced.
[0120]
(Evaluation)
The sample was cut to 3.5 cm × 15 cm, exposed with a laser sensitometer equipped with an 810 nm diode, then processed (developed) at 120 ° C. for 15 seconds, and Dmin and maximum image density were evaluated. The maximum image density is expressed as a relative density where the maximum image density of the sample 11 is 100.
[0121]
[Table 1]

[0122]
From Table 1, it is clear that the sample of the present invention has lower fog and higher image density than the comparative sample.
[0123]
  referenceExample1
  thisreferenceIn the examples, the evaluation was performed by changing the wind speed conditions during drying.
[0124]
Samples 21 to 24 were obtained in the same manner as in Example 1 except that the drying speed was 40 ° C. and the wind speed was changed to the conditions shown in Table 2.
[0125]
(Evaluation)
Samples 21 to 24 were cut to 3.5 cm × 15 cm, exposed with a laser sensitometer equipped with an 810 nm diode, then processed (developed) at 120 ° C. for 15 seconds, and Dmin and maximum image density were evaluated. Indicated. The maximum image density is expressed as a relative density where the maximum image density of the sample 21 is 100.
[0126]
[Table 2]

[0127]
  From Table 2, TryFee22-24 is a trialFee21It is clear that the image has low fog and high image density.
[0128]
  referenceExample2
  thisreferenceIn the examples, evaluation was performed by changing the particle size after crushing of the wet cake-like organic silver salt composition.
[0129]
  The above except that the maximum particle size after crushing of the wet cake-like organic silver salt composition in the drying step was changed to the conditions shown in Table 3 and drying was performed.referenceExample1In the same manner as Sample 24, Samples 31 to 34 were obtained.
[0130]
(Evaluation)
Samples 31-34 were cut to 3.5 cm × 15 cm and exposed with a laser sensitometer equipped with an 810 nm diode, then the photographic material was processed (developed) at 120 ° C. for 15 seconds to evaluate Dmin and maximum image density, It is shown in Table 3. The maximum image density is expressed as a relative density where the maximum image density of the sample 31 is 100.
[0131]
[Table 3]

[0132]
  From Table 3, TryFee32-34 is a trialFee31It is clear that the image has low fog and high image density.
[0133]
  ComparisonExample3
  thisComparisonIn the examples, evaluation was performed by changing the water content of the dried organic silver salt composition powder.
[0134]
  The above except that the moisture content of the organic silver salt composition was changed to the conditions shown in Table 4 and dried.ComparisonExample2In the same manner as Sample 34, Samples 41 to 44 were obtained.
[0135]
(Evaluation)
Samples 41-44 were cut to 3.5 cm × 15 cm and exposed with a laser sensitometer equipped with an 810 nm diode, then the photographic material was processed (developed) at 120 ° C. for 15 seconds to evaluate Dmin and maximum image density, It is shown in Table 4. The maximum image density is expressed as a relative density with the maximum image density of the sample 41 as 100.
[0136]
[Table 4]

[0137]
  From Table 4, TryFee42-44 is a trialFee41It is clear that the image has low fog and high image density.
[0138]
【The invention's effect】
According to the present invention, a method for producing a photothermographic material containing an organic silver salt with low fog, high image density and low cost can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a fluidized bed drying apparatus used in the present invention.
[Explanation of symbols]
1 Air supply inlet
2 Raw material inlet
3 Drying room
4 Bug filters
5 Exhaust port
6 eye plate
7 Product discharge section

Claims (4)

In the method for producing a photothermographic material containing an organic silver salt composition, the drying temperature in the drying step of the organic silver salt composition is 38 ° C. or less, and the drying time is within 32 hours. A method for producing a photothermographic material. 2. The process for producing a photothermographic material according to claim 1, wherein the wind speed in the drying step of the organic silver salt composition is 2 m / s or less. 3. The method for producing a photothermographic material according to claim 1, wherein the drying step of the organic silver salt composition is pulverized to a particle size of 10 mm or less . The method of manufacturing a photothermographic material comprising an organic silver salt composition, any one of the preceding claims, characterized in that the water content of 0.2% or less by drying of the organic silver salt composition 2. A process for producing a photothermographic material according to item 1 .

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