JP4035936B2 - Heat developing material and method for producing heat developing material - Google Patents

Description

【００６２】
式中、Ｒは水素原子、又は炭素原子数１〜１０のアルキル基（例えば、−Ｃ₄Ｈ₉、２，４，４−トリメチルペンチル）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、エチル、ｔ−ブチル）を表す。
【００６３】
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、以下の化合物に限定されるものではない。
【００６４】
【化２】

【００６５】
【化３】

【００６６】
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１×１０^-2〜１０モル、特に１×１０^-2〜１．５モルである。
【００６７】
本発明の熱現像写真感光材料に好適なバインダーは透明又は半透明で、一般に無色であり、天然ポリマー、合成樹脂やポリマー及びコポリマー、その他フィルムを形成する媒体、例えば：ゼラチン、アラビアゴム、ポリ（ビニルアルコール）、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。親水性でも疎水性でもよい。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、画像形成層の外側に非感光層を有することができる。これらの非感光層に用いられるバインダーは画像形成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。
【００６８】
本発明においては、熱現像の速度を速めるために画像形成層のバインダー量が１．５〜１０ｇ／ｍ²であることが好ましい。さらに好ましくは１．７〜８ｇ／ｍ²である。
【００６９】
本発明においては、画像形成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、そのマット剤を画像形成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。
【００７０】
本発明において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。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。マット剤の粒径は球形換算した直径のことを示すものとし、平均粒径が０．５μｍ〜１０μｍであることが好ましく、更に好ましくは１．０μｍ〜８．０μｍである。又、
（粒径の標準偏差）／（粒径の平均値）×１００
で表される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。マット剤は任意の構成層中に含むことができるが、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。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。
【００７１】
本発明の熱現像感光材料は支持体上に少なくとも一層の感光性画像形成層を有している。支持体の上に画像形成層のみを形成しても良いが、画像形成層の上に少なくとも１層の非感光層を形成することが好ましい。画像形成層に通過する光の量又は波長分布を制御するために該層と同じ側にフィルター染料層および／又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、画像形成層に染料又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。
【００７２】
またこれらの非感光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、さら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。
【００７３】
画像形成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／低感層又は低感層／高感層にしても良い。
【００７４】
本発明の熱現像材料は、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ものであることが好ましい。
【００７５】
色調剤は有機銀塩と還元剤の酸化還元反応に関与して、生ずる銀画像を濃色、特に黒色にする機能を有する。本発明に用いられる好適な色調剤の例はＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ第１７０２９号に開示されている。特に好ましい色調剤はフタラゾン又はフタラジンである。
【００７６】
本発明には現像を抑制あるいは促進させ現像を制御するため、分光増感効率を向上させるため、現像前後の保存性を向上させるためなどにメルカプト化合物、ジスルフィド化合物、チオン化合物を含有させることができる。
【００７７】
本発明の熱現像感光材料中にはかぶり防止剤が含まれて良い。最も有効なかぶり防止剤として知られているものは水銀イオンである。感光材料中にかぶり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。非水銀かぶり防止剤としては例えば米国特許第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かぶり防止剤が好ましい。
【００７８】
本発明の熱現像材料には、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。本発明に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Ｉｔｅｍ１８３１Ｘ項（１９７８年８月ｐ．４３７）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。
【００７９】
本発明の熱現像材料には、画像を硬調化させる目的で、ヒドラジン化合物を感材中に含有させてもよい。本発明に用いられる好ましいヒドラジン化合物としては、Ｒｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ Ｉｔｅｍ ２３５１５（１９８３年１１月号、Ｐ．３４６）及びそこに引用された文献の他、米国特許第４，０８０，２０７号、同第４，２６９，９２９号、同第４，２７６，３６４号、同第４，２７８，７４８号、同第４，３８５，１０８号、同第４，４５９，３４７号、同第４，４７８，９２８号、同第４，５６０，６３８号、同第４，６８６，１６７号、同第４，９１２，０１６号、同第４，９８８，６０４号、同第４，９９４，３６５号、同第５，０４１，３５５号、同第５，１０４，７６９号、英国特許第２，０１１，３９１Ｂ号、欧州特許第２１７，３１０号、同第３０１，７９９号、同第３５６，８９８号、特開昭６０−１７９７３４号、同６１−１７０７３３号、同６１−２７０７４４号、同６２−１７８２４６号、同６２−２７０９４８号、同６３−２９７５１号、同６３−３２５３８号、同６３−１０４０４７号、同６３−１２１８３８号、同６３−１２９３３７号、同６３−２２３７４４号、同６３−２３４２４４号、同６３−２３４２４５号、同６３−２３４２４６号、同６３−２９４５５２号、同６３−３０６４３８号、同６４−１０２３３号、特開平１−９０４３９号、同１−１００５３０号、同１−１０５９４１号、同１−１０５９４３号、同１−２７６１２８号、同１−２８０７４７号、同１−２８３５４８号、同１−２８３５４９号、同１−２８５９４０号、同２−２５４１号、同２−７７０５７号、同２−１３９５３８号、同２−１９６２３４号、同２−１９６２３５号、同２−１９８４４０号、同２−１９８４４１号、同２−１９８４４２号、同２−２２００４２号、同２−２２１９５３号、同２−２２１９５４号、同２−２８５３４２号、同２−２８５３４３号、同２−２８９８４３号、同２−３０２７５０号、同２−３０４５５０号、同３−３７６４２号、同３−５４５４９号、同３−１２５１３４号、同３−１８４０３９号、同３−２４００３６号、同３−２４００３７号、同３−２５９２４０号、同３−２８００３８号、同３−２８２５３６号、同４−５１１４３号、同４−５６８４２号、同４−８４１３４号、同２−２３０２３３号、同４−９６０５３号、同４−２１６５４４号、同５−４５７６１号、同５−４５７６２号、同５−４５７６３号、同５−４５７６４号、同５−４５７６５号、同６−２８９５２４号、同９−１６０１６４号等に記載されたものを挙げることが出来る。
【００８０】
この他にも、特公平６−７７１３８号に記載の（化１）で表される化合物で、具体的には同公報３頁、４頁に記載された化合物、特公平６−９３０８２号公報に記載された一般式（１）で表される化合物で具体的には同公報８頁〜１８頁に記載の１〜３８の化合物、特開平６−２３０４９号公報に記載の一般式（４）、（５）及び（６）で表される化合物で、具体的には同公報２５頁、２６頁に記載の化合物４−１〜４−１０、２８頁〜３６頁に記載の化合物５−１〜５−４２、及び３９頁、４０頁に記載の化合物６−１〜６−７、特開平６−２８９５２０号公報に記載の一般式（１）及び（２）で表される化合物で、具体的には同公報５頁から７頁に記載の化合物１−１）〜１−１７）及び２−１）、特開平６−３１３９３６号公報に記載の（化２）及び（化３）で表される化合物で具体的には同公報６頁から１９頁に記載の化合物、特開平６−３１３９５１号公報に記載の（化１）で表される化合物で、具体的には同公報３頁から５頁に記載された化合物、特開平７−５６１０号公報に記載の一般式（Ｉ）で表される化合物で、具体的には同公報の５頁から１０頁に記載の化合物Ｉ−１〜Ｉ−３８、特開平７−７７７８３号公報に記載の一般式（II）で表される化合物で、具体的には同公報１０頁〜２７頁に記載の化合物II−１〜II−１０２、特開平７−１０４４２６号公報に記載の一般式（Ｈ）及び一般式（Ｈａ）で表される化合物で、具体的には同公報８頁から１５頁に記載の化合物Ｈ−１からＨ−４４に記載されたもの等を用いることが出来る。
【００８１】
各種の添加剤は画像形成層、非感光層、又はその他の形成層のいずれに添加しても良い。本発明の熱現像材料には例えば、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。
【００８２】
本発明の熱現像材料の露光は、アルゴンイオンレーザー（４８８ｎｍ）、Ｈｅ−Ｎｅレーザー（６３３ｎｍ）、赤色半導体レーザー（６７０ｎｍ）、赤外半導体レーザー（７８０ｎｍ、８２０ｎｍ）等が好ましく用いられるが、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がより好ましく用いられる。
【００８３】
露光はレーザー走査露光により行うことが好ましいが、感光材料の露光面と走査レーザー光のなす角が実質的に垂直になることがないレーザー走査露光機を用いることが好ましい。ここで、「実質的に垂直になることがない」とはレーザー走査中に最も垂直に近い角度として好ましくは５５度以上８８度以下、より好ましくは６０度以上８６度以下、更に好ましくは６５度以上８４度以下、最も好ましくは７０度以上８２度以下であることをいう。
【００８４】
レーザー光が、感光材料に走査されるときの感光材料露光面でのビームスポット直径は、好ましくは２００μｍ以下、より好ましくは１００μｍ以下である。これは、スポット径が小さい方がレーザー入射角度の垂直からのずらし角度を減らせる点で好ましい。なお、ビームスポット直径の下限は１０μｍである。このようなレーザー走査露光を行うことにより干渉縞様のムラの発生等のような反射光に係る画質劣化を減じることが出来る。
【００８５】
また露光は縦マルチである走査レーザー光を発するレーザー走査露光機を用いて行うことも好ましい。縦単一モードの走査レーザー光に比べて干渉縞様のムラの発生等の画質劣化が減少する。縦マルチ化するには、合波による、戻り光を利用する、高周波重畳をかける、などの方法がよい。なお、縦マルチとは、露光波長が単一でないことを意味し、通常露光波長の分布が５ｎｍ以上、好ましくは１０ｎｍ以上になるとよい。露光波長の分布の上限には特に制限はないが、通常６０ｎｍ程度である。
【００８６】
本発明の熱現像感光材料は常温で安定であるが、露光後高温に加熱することで現像される。加熱温度としては８０℃以上２００℃以下が好ましく、さらに好ましいのは１００℃以上１５０℃以下である。加熱温度が８０℃以下では短時間に十分な画像濃度が得られず、又２００℃以上ではバインダーが溶融し、ローラーへの転写など、画像そのものだけでなく搬送性や、現像機等へも悪影響を及ぼす。処理時間としては５秒以上６０秒以下が好ましく、さらに好ましいのは８秒以上３０秒以下である。処理時間が５秒以下では、処理による濃度ムラが発生しやすくなる。また、６０秒以上ではカブリの発生や、支持体の変形が起きやすくなる。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により銀画像を生成する。この反応過程は、外部からの水等の処理液の供給なしに進行する。
【００８７】
熱現像処理した後の、４００ｎｍにおける支持体を含んだ熱現像材料の光学透過濃度が０．２以下であることが好ましい。光学透過濃度の更に好ましい値は０．０２以上０．２以下である。
【００８８】
【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。
【００８９】
参考例１
［下引済み支持体の作製］
厚さ１２０μｍのポリエチレンテレフタレート支持体の両面に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下引層Ｂ−１とした。
【００９０】

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。
【００９１】
《下引上層塗布液ａ−２》
ゼラチン ０．４ｇ／ｍ²になる量
（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（重量平均分子量６００） ６ｇ
水で１ｌに仕上げる
【００９２】
【化４】

【００９３】
【化５】

【００９４】
（ハロゲン化銀乳剤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を含む水溶液及び塩化ロジウムを銀１モル当たり１×１０^-4モルを、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０．３ｇを添加しＮａＯＨでｐＨを５に調整して平均粒子サイズ０．０６μｍ、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フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整して、ハロゲン化銀乳剤Ａを得た。
【００９５】
特開平９−１２７６４３号実施例１の方法に従い下記のような方法でベヘン酸銀を作製した。
【００９６】
（ベヘン酸Ｎａ溶液の調製）
３４０ｍｌのイソプロパノールにベヘン酸３４ｇを６５℃で溶解した。次に攪拌しながら０．２５Ｎの水酸化ナトリウム水溶液をｐＨ８．７になる様に添加した。この際水酸化ナトリウム水溶液は約４００ｍｌ必要とした。次にこのベヘン酸ナトリウム水溶液を減圧濃縮を行いベヘン酸ナトリウムの濃度が質量％で８．９％とした。
【００９７】
（ベヘン酸銀の調製）
７５０ｍｌの蒸留水中に３０ｇのオセインゼラチンを溶解した溶液に２．９４Ｍの硝酸銀溶液を加え銀電位を４００ｍＶとした。この中にコントロールドダブルジェット法を用いて７８℃の温度下で前記ベヘン酸ナトリウム溶液３７４ｍｌを４４．６ｍｌ／分のスピードで添加し同時に２．９４Ｍの硝酸銀水溶液を銀電位が４００ｍＶになる様に添加した。添加時のベヘン酸ナトリウム及び硝酸銀の使用量はそれぞれ０．０９２モル、０．１０１モルであった。
【００９８】
添加終了後さらに３０分攪拌し限外濾過により水溶性塩類を除去した。
（感光性乳剤Ａの調製）
このベヘン酸銀分散物に前記ハロゲン化銀乳剤Ａをそれぞれ０．０１モル加え、更に攪拌しながらポリ酢酸ビニルの酢酸ｎ−ブチル溶液（１．２質量％）１００ｇを徐々に添加して分散物のフロックを形成後、水を取り除き、更に２回の水洗と水の除去を行った後、バインダーとしてポリビニルブチラール（平均分子量３０００）の２．５質量％の酢酸ブチルとイソプロピルアルコールの１：２混合溶液６０ｇを攪拌しながら加えた後、こうして得られたゲル状のベヘン酸及びハロゲン化銀の混合物にバインダーとしてポリビニルブチラール（平均分子量４０００）及び表１記載の溶媒を加え分散し、感光性乳剤Ａを調製した。
【００９９】
上記で下引層を施した支持体上に以下の各層を順次形成し、試料を作製した。尚、乾燥は各々７５℃，５分間で行った。
【０１００】
（バック面側塗布）
ポリビニルブチラール ８ｇ／ｍ²
染料−Ｂ ７０ｍｇ／ｍ²
染料−Ｃ ７０ｍｇ／ｍ²
からなる組成物を表１に記載の溶媒に加えた塗布液を湿潤厚さ８０ミクロンになるように塗布した。
【０１０１】
【化６】

【０１０２】
（画像形成層面側塗布）
画像形成層１：以下の組成物を塗布銀量が２．０ｇ／ｍ²、バインダーとしてのポリビニルブチラールを８ｇ／ｍ²になる様に表１記載の溶媒に加えて塗布液とし、塗布乾燥した。
【０１０３】

【０１０４】
【化７】

【０１０５】
表面保護層：以下の組成物を表１記載の溶媒に加えて調製した塗布液を湿潤厚さ１００μｍになる様に各画像形成層上に塗布乾燥した。
【０１０６】
セルロースアセテート ８．０ｇ／ｍ²
フタラジン １．０ｇ／ｍ²
４−メチルフタル酸 ０．７２ｇ／ｍ²
テトラクロロフタル酸 ０．２２ｇ／ｍ²
テトラクロロフタル酸無水物 ０．５ｇ／ｍ²
シリカマット剤（平均粒径５μｍ） ０．５ｇ／ｍ²
なお、表１記載の溶媒に溶解しにくいものは、少量のジメチルホルムアミド（ＤＭＦ）等の可溶化する溶媒を用いて溶解するか、表１記載の溶媒に固体分散させて添加した。
【０１０７】
《熱現像材料の平衡含水率の測定》
得られた熱現像材料を２５℃、６０％ＲＨの環境下で２４時間調湿した後、同雰囲気下で、フィルム面積として４６．３ｃｍ²を切り出し質量を測定した後、これを５ｍｍ程度に細かく刻んで専用バイアル瓶に収納しセプタムとアルミキャップで密閉した後、ヒューレット・パッカード社製ヘッドスペースサンプラーＨＰ７６９４型にセットした。ヘッドスペースサンプラー加熱条件：１２０℃、２０分で蒸発した水分をカールフィッシャー法にて定量した。
【０１０８】
《写真性能の評価》
上記で作製した熱現像材料を２つに折半し、ひとつは波長７８０ｎｍの半導体レーザーを有するレーザー感光計で露光した。その後ヒートドラムを用いて１３０℃で２５秒熱現像処理した。その際、露光及び現像は２５℃、６０％ＲＨに調湿した部屋で行った。得られた画像の評価（感度とカブリおよび最高濃度（Ｄｍａｘ））を濃度計により行った（常温写真性）。感度はカブリ（最低）濃度（Ｄｍｉｎ）より０．３高い濃度を与える露光量の比の逆数で評価し塗布試料Ｎｏ．１を基準として相対評価で表わした。なお、熱現像材料の露光面と露光レーザー光の角度は８０度とした。上記の測定は熱現像材料を２４時間２５℃、６０％ＲＨの雰囲気下に置いた後に行った。のこりは、２５℃、６０％ＲＨの雰囲気下で複数枚のシートに分け、表裏を接触させて防湿袋に封入したのち、５５℃で３日間加熱保存したのちに上と同様の評価を実施した（経時代用写真性）。
【０１０９】
評価した結果を表１に示す。
【０１１０】
【表１】

【０１１１】
参考例２
（支持体の作製）
濃度０．１７０（コニカ（株）製デンシトメータＰＤＡ−６５）に青色着色した、厚み１７５μｍのＰＥＴフィルムの両面に８Ｗ／ｍ²・分のコロナ放電処理を施した。
【０１１２】
（感光性ハロゲン化銀乳剤Ｂの調製）
水９００ｍｌ中に平均分子量１０万のオセインゼラチン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を含む水溶液及び塩化イリジウムを銀１モル当たり１×１０^-4モルを、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０．３ｇ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１２％、〔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フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整して、感光性ハロゲン化銀乳剤Ｂを得た。
【０１１３】
（粉末有機銀塩Ｂの調製）
９４５０ｍｌの純水にベヘン酸３２４ｇ、アラキジン酸９９ｇ、ステアリン酸５６ｇを８０℃で溶解した。次に高速で攪拌しながら１．５Ｍの水酸化ナトリウム水溶液９８０ｍｌを添加した。次に濃硝酸９.３ｍｌを加えた後、５５℃に冷却して３０分攪拌させて前記ハロゲン化銀乳剤Ｂ（銀量として０．９モルおよび水１４００ｇを含有）を５秒間で添加し５分間攪拌した後に１Ｍの硝酸銀溶液１４７０ｍｌを２分間かけて加え、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、遠心脱水を実施した後、３７℃にて質量減がなくなるまで温風乾燥を行い、粉末有機銀塩Ｂを得た。
【０１１４】
（感光性乳剤分散液の調製）
ポリビニルブチラール粉末（Ｍｏｎｓａｎｔｏ社 Ｂｕｔｖａｒ Ｂ−７９）１４．５７ｇをメチルエチルケトン１４５７ｇに溶解し、ディゾルバー型ホモジナイザにて攪拌しながら粉末有機銀塩Ｂ５００ｇを徐々に添加して十分に混合した。その後１ｍｍＺｒビーズ（東レ製）を８０％充填したメディア型分散機（ｇｅｔｔｚｍａｎｎ社製）にて周速１３ｍ、ミル内滞留時間３分間にて分散を行ない感光性乳剤分散液を調製した。
【０１１５】
〈赤外増感色素液の調製〉
増感色素−２ ３５０ｍｇ、２−クロロ−安息香酸１３．９６ｇ、および５−メチル−２−メルカプトベンズイミダゾール２．１４ｇをメタノール７３．４ｍｌに暗所にて溶解し赤外増感色素液を調製した。
【０１１６】
〈安定剤液の調製〉
安定剤−１ １．０ｇ、酢酸カリウム０．５ｇをメタノール８．５ｇに溶解し安定剤液を調製した。
【０１１７】
〈現像剤液の調製〉
現像剤−２ １７．７４ｇをＭＥＫに溶解し、１００ｍｌに仕上げ、現像剤液とした。
【０１１８】
〈カブリ防止剤液の調製〉
カブリ防止剤−５ ５．８１ｇをＭＥＫに溶解し、１００ｍｌに仕上げ、かぶり防止剤液とした。
【０１１９】
（画像形成層塗布液の調製）
前記感光性乳剤分散液（５０ｇ）およびＭＥＫ１５．１１ｇを攪拌しながら２１℃に保温し、カブリ防止剤−４（１０％メタノール溶液）３９０μｌを加え、１時間攪拌した。さらに臭化カルシウム（１０％メタノール溶液）８８９μｌを添加して３０分攪拌した。
【０１２０】
次に、赤外増感色素液１．４１６ｍｌおよび安定剤液６６７μｌを添加して１時間攪拌した後に温度を１３℃まで降温してさらに３０分攪拌した。１３℃に保温したまま、ポリビニルブチラール（Ｍｏｎｓａｎｔｏ社 Ｂｕｔｖａｒ Ｂ−７９）１３．３１ｇを添加して３０分攪拌してから、さらに攪拌を続けながら以下の添加物を１５分間隔で添加した。
【０１２１】

を順次添加し攪拌することにより画像形成層塗布液を得た。
【０１２２】
【化８】

【０１２３】

からなる組成の液を調製した。
【０１２４】
上記で得た塗布液をそれぞれ５つ用意し、画像形成層塗布液は、１５℃で表２に示す乾燥剤を詰めたカラムに通過させた直後に塗布し７５℃、５分間乾燥し、熱現像材料を作製した。なお、塗布銀量は２ｇ／ｍ²になる様に塗布した。
【０１２５】
《塗布液の含水率の測定》
上記で調製した塗布液を用いて装置として京都電子（株）社製ＭＫＡ−２１０を用いてカールフィッシャー法により測定した。カールフィッシャー試薬ＳＳとしては三菱化学Ｎｏ．Ｅ９８０６２、また、脱水溶剤ＣＭとしては三菱化学Ｎｏ．Ｌ９７９８８を使用した。
【０１２６】
なお、熱現像材料の平衡含水率の測定は参考例１と同様にした。
《露光及び現像処理》
上記のように作製した感光材料をふたつに折半し、一方の乳剤面側から、高周波重畳にて波長８００ｎｍ〜８２０ｎｍの縦マルチモード化された半導体レーザーを露光源とした露光機によりレーザー走査による露光を与えた。この際に、感光材料の露光面と露光レーザー光の角度を７５度として画像を形成した（なお、当該角度を９０度とした場合に比べムラが少なく、かつ予想外に鮮鋭性等が良好な画像が得られた。）。
【０１２７】
その後、ヒートドラムを有する自動現像機を用いて感光材料の保護層とドラム表面が接触するようにして、１１０℃で１５秒熱現像処理した。その際、露光及び現像は２５℃、６０％ＲＨに調湿した部屋で行った（常温写真性）。得られた画像の評価を濃度計により行った。測定の結果は、感度（未露光部分よりも１．０高い濃度を与える露光量の比の逆数）およびカブリで評価し、感光材料１の感度を１００とする相対値で示した。のこりは、２５℃、６０％ＲＨの雰囲気下で複数枚のシートに分け、表裏を接触させて防湿袋に封入したのち、５５℃で３日間加熱保存したのちに上と同様の評価を実施した（経時代用写真性）。
【０１２８】
評価した結果を表２に示す。
【０１２９】
【表２】

【０１３０】
参考例３
参考例２と同様にして支持体を作製し、感光性ハロゲン化銀乳剤Ｂを調製した。
【０１３１】
（粉末有機銀塩の調製）
４７２０ｍｌ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１．５Ｍ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℃に冷却して有機酸ナトリウム溶液を得た。この溶液を５５℃に保ったまま、前記ハロゲン化銀乳剤Ｂ（銀０．０３８モル含む）と純水４５０ｍｌを添加し５分間攪拌した後に１Ｍの硝酸銀溶液７６０．６ｍｌを２分間かけて加え、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、遠心脱水を実施した後、３７℃にて温風乾燥を行った。この時、乾燥時間を変化させることで粉末有機銀塩の含水量を変化させて、以下の評価に用いた。含水量は得られた有機銀塩粉末を高温で乾燥させたときの質量を測定して算出した。
【０１３２】
【表３】

【０１３３】
感光性乳剤分散液及び赤外増感色素液（増感色素−２に代えて、増感色素−１を用いた）を参考例２と同様にして調製した。
【０１３４】
（画像形成層塗布液の調製）
前記感光性乳剤分散液（５００ｇ）およびＭＥＫ１００ｇを攪拌しながら２１℃に保温し、ビス（ジメチルアセトアミド）ジブロモブロメート０．０２ｇを加え、１時間攪拌した。
【０１３５】
次に、赤外増感色素液１．５ｍｌを添加して１時間攪拌した後に温度を１３℃まで降温してさらに３０分攪拌した。１３℃に保温したまま、ポリビニルブチラール（前出）４８ｇを添加して充分溶解してから、
フタラジン １．５ｇ
テトラクロロフタル酸 ０．５ｇ
４−メチルフタル酸 ０．５ｇ
２−（トリブロモメチル−スルホニル）−ピリジン １．９ｇ
現像剤−２ １５ｇ
脂肪族イソシアネート（前出） １．１０ｇ
を添加した。
【０１３６】
この調製を、湿度８０％ＲＨ、５０％ＲＨ、３５％ＲＨ及び窒素置換の時間を全工程に掛かる時間の３０％、５０％、１００％と条件を変化させて行った。各塗布液の調製条件と含水量について表４に示す。尚、含水量の測定は実施例２と同様に行った。
【０１３７】
【表４】

【０１３８】
支持体上に以下の各層を順次形成し、７５℃で５分間乾燥して試料を作製した。
【０１３９】
（バック面側塗布）
ポリビニルブチラール １５０ｍｌ
染料−Ｂ ７０ｍｇ
染料−Ｃ ７０ｍｇ
からなる組成の塗布液を湿潤厚さ８０μｍになる様に塗布した。
【０１４０】
（画像形成層面側塗布）
前記画像形成層塗布液を、塗布銀量が２．０ｇ／ｍ²、バインダーとしてのポリビニルブチラールを８．５ｇ／ｍ²になる様に塗布した。
【０１４１】
次いで、
アセトン １７５ｍｌ
メタノール １５ｍｌ
セルロースアセテートブチレート ８．０ｇ
フタラジン １．０ｇ
４−メチルフタル酸 ０．７２ｇ
テトラクロロフタル酸 ０．２２ｇ
テトラクロロフタル酸無水物 ０．５ｇ
平均粒径４μｍの単分散シリカ バインダーに対して１質量％
からなる組成の表面保護層塗布液を湿潤厚さ１００μｍで塗布した。
【０１４２】
《露光及び現像処理》
上記のように作製した感光材料の乳剤面側から、参考例２と同様にしてレーザー走査による露光を与え、感光材料の露光面と露光レーザー光の角度を７５度として画像を形成した（なお、ムラが少なく、予想外に鮮鋭性等が良好な画像が得られたのは参考例２と同様である。）。
【０１４３】
その後、参考例２と同様にして熱現像処理した。但し、露光及び現像は２５℃、５０％ＲＨに調湿した部屋で行い、得られた画像の評価を濃度計により行った。感度及びカブリで評価し、同様に感光材料試料Ｎｏ．１のＮ＝１の感度を１００とする相対値で示した。更に、各画像形成層塗布液の調製を３回（Ｎ＝３）ずつ行って、センシトメトリを評価し、製造安定性の評価とした。
【０１４４】
結果を表５に示す。
【０１４５】
【表５】

【０１４６】
（▲４▼〜▲６▼の発明に係る実施例）
実施例４
〈写真用支持体の作製〉
以下のようにしてポリマー樹脂を得た。
【０１４７】
（ＰＥＴ樹脂）
テレフタル酸ジメチル１００質量部、エチレングリコール６５質量部にエステル交換触媒として酢酸マグネシウム水和物０．０５質量部を添加し、常法に従ってエステル交換を行った。得られた生成物に、三酸化アンチモン０．０５質量部、リン酸トリメチルエステル０．０３質量部を添加した。次いで、徐々に昇温、減圧にし、２８０℃、０．５ｍｍＨｇで重合を行い、固有粘度０．５０のポリエチレンテレフタレート（ＰＥＴ）樹脂を得た。
【０１４８】
（ＰＥＮ樹脂）
２，６−ナフタレンジカルボン酸ジメチル１００質量部、エチレングリコール６０質量部にエステル交換触媒として酢酸マグネシウム水和物０．１質量部を添加し、常法に従ってエステル交換を行った。得られた生成物に、三酸化アンチモン０．０５質量部、リン酸トリメチルエステル０．０３質量部を添加した。次いで、徐々に昇温、減圧にし、２９０℃、０．５ｍｍＨｇで重合を行い、固有粘度０．５８のポリエチレン−２，６−ナフタレート（ＰＥＮ）樹脂を得た。
【０１４９】
（共重合ＰＥＴ樹脂（Ｍ−ＰＥＴ樹脂））
テレフタル酸ジメチル１００質量部、エチレングリコール５６質量部、５−ナトリウムスルホ−ジ（β−ヒドロキシエチル）イソフタル酸のエチレングリコール溶液（濃度３５％）を２８質量部添加し、エステル交換触媒として酢酸マグネシウム水和物０．１質量部を添加し、常法に従ってエステル交換を行った。得られた生成物に、三酸化アンチモン０．０４質量部、リン酸トリメチルエステル０．１質量部を添加した。次いで、徐々に昇温、減圧にし、２８５℃、０．５ｍｍＨｇで重合を行い、固有粘度０．４０のポリエチレンテレフタレートが主成分の共重合ポリエステル（Ｍ−ＰＥＴ）樹脂を得た。
【０１５０】
以上のようにして得られたそれぞれのポリマーを用いて、以下のようにして二軸延伸ポリマーフィルムを作製した。
【０１５１】
（ＰＥＴ支持体フィルムおよびＭ−ＰＥＴ支持体フィルム）
ＰＥＴ樹脂またはＭ−ＰＥＴ樹脂をペレット化したものを１５０℃で８時間真空乾燥した後、２８５℃でＴダイから層状に溶融押しだし、３０℃の冷却ドラム上で静電印加しながら密着させ、冷却固化させ、未延伸フィルムを得た。この未延伸シートをロール式縦延伸機を用いて、８０℃で縦方向に３．３倍延伸した。得られた一軸延伸フィルムをテンター式横延伸機を用いて、第一延伸ゾーン９０℃で総横延伸倍率の５０％延伸し、さらに第二延伸ゾーン１００℃で総横延伸倍率３．３倍になるように延伸した。次いで、７０℃２秒間、前熱処理し、さらに第一固定ゾーン１５０℃で５秒間熱固定し、第二固定ゾーン２２０℃で１５秒間熱固定した。次いで横方向に５％弛緩処理しながら室温まで６０秒かけて冷却し、フィルムをクリップから解放し、巻き取り、厚さ１８０μｍの二軸延伸フィルムを得た。
【０１５２】
（ＰＥＮ支持体フィルム）
比較例１のＰＥＴ樹脂の代わりにＰＥＮ樹脂を使用し、溶融押し出し温度３００℃、冷却ドラム温度５０℃、縦延伸温度１３５℃、第一横延伸ゾーン温度１４５℃、第二横延伸ゾーン温度１５５℃、前熱処理温度１００℃、第一固定ゾーン温度２００℃、第二固定ゾーン温度２３０℃を変更させて行った以外、比較例１と同様にして、厚さ１８０μｍの二軸延伸フィルムを得た。
【０１５３】
〈下引済み写真用支持体の作製〉
上記で作製した厚さ１８０μｍの写真用支持体の熱現像画像形成層を塗設する側に８ｗ／ｍ²・分のコロナ放電処理を施し、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とした。いくつかの試料には更に、１００℃で１０分間の熱処理を施し、巻き取り後直ちに防湿シートでカバーをした。
【０１５４】
《下引塗布液ａ′−１》
ポリエステル系ラテックス液ｂ−１（固形分１５％） ２５０ｇ
（Ｃ′−１） ０．６ｇ
水で１ｌに仕上げる
【０１５５】
【化９】

【０１５６】
〈バッキング層の塗設〉
下引き済み写真用支持体の下引きした側と反対側に、下記に示すバッキング層塗布液Ｂ′−１を下記に示す付量になるように塗布乾燥した。尚、乾燥は１００℃，５分間で行った。
【０１５７】

（ハロゲン化銀乳剤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５１ｇと沃化カリウム１．５ｇを含む水溶液３５０ｍｌ及び〔Ｉｒ（ＮＯ）Ｃｌ₅〕塩を銀１モル当たり１×１０^-6モル及び塩化ロジウム塩を銀１モル当たり１×１０^-4モルを、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、単分散度１０％の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フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整して、ハロゲン化銀乳剤Ａ′を得た。さらに塩化金酸及び無機硫黄で化学増感を行った。
【０１５８】
（ベヘン酸Ｎａ溶液の調製）
９４５ｍｌの純水にベヘン酸３２．４ｇ、アラキジン酸９．９ｇ、ステアリン酸５．６ｇを加え９０℃で混合攪拌した。次に高速で攪拌しながら１．５Ｎの水酸化ナトリウム水溶液９８ｍｌを添加した。次に濃硝酸０．９３ｍｌを加えた後、５５℃に冷却して３０分攪拌させてベヘン酸Ｎａ溶液を得た。
【０１５９】
（ベヘン酸Ｎａとハロゲン化銀Ａ′とからのプレフォーム乳剤Ａ′の調製）
上記のベヘン酸Ｎａ溶液に前記ハロゲン化銀乳剤Ａ′を１５．１ｇ添加し水酸化ナトリウム溶液でｐＨ８．１に調整した後に１Ｍの硝酸銀溶液１４７ｍｌを７分間かけて加え、さらに２０分攪拌し限外濾過により水溶性塩類を除去した。できたベヘン酸銀は平均粒子サイズ０．８μｍ、単分散度８％の粒子であった。分散物のフロックを形成後、水を取り除き、更に６回の水洗と水の除去を行った後乾燥させた。これをプレフォーム乳剤Ａ′とする。
【０１６０】
（感光性乳剤Ａ′の調製）
できあがったプレフォーム乳剤Ａ′にポリビニルブチラール（平均分子量３０００）のメチルエチルケトン溶液（１７質量％）５４４ｇとトルエン１０７ｇを徐々に添加して混合した後に、４０００ｐｓｉで分散させた。これを感光性乳剤Ａ′とする。
【０１６１】

からなる組成の液を塗布銀量が２．１ｇ／ｍ²になる様に塗布した。
【０１６２】

からなる組成の液を画像形成層の上に塗布した。
【０１６３】
バッキング層、画像形成層、表面保護層の塗布は、表６に示す相対湿度に調整した工程で３時間調湿後、バッキング層を塗布し、次いで画像形成層と表面保護層を同時重層で塗布し、乾燥温度８０℃で５分間乾燥した。但し、前工程で熱処理を行い防湿シートをカバーしたものについては、シートを除去後、直ちに塗布を行った。
【０１６４】
《露光及び現像処理》
上記で作製した熱現像感光材料に８１０ｎｍ、１００ｍＷの半導体レーザーを有するイメージャーで、縦５ｃｍ横５ｃｍベタの走査露光（ビーム径８μｍ、走査ピッチ５μｍ）を行い、潜像を形成した。その後ヒートドラムを有する自動現像機を用いて、熱現像画像形成層側にヒートドラムが接するように１１０℃で１５秒間、熱現像処理した。その際、露光及び現像は２３℃、５０％ＲＨに調湿した部屋で行った。
【０１６５】
《画像形成材料の評価》
（熱画像寸法安定性）
熱処理現像後、形成された画像の正方形の縦横それぞれの辺の長さを測定し、その長さと露光後の長さ（５ｃｍ）との差の率を熱画像寸法安定度とし、
Ａ：０．０１未満
Ｂ：０．０１以上０．０２未満
Ｃ：０．０２以上０．０４未満
Ｄ：０．０４以上０．０６未満
Ｅ：０．０６以上
で評価した。
【０１６６】
（膜付き）
１２０℃の熱現像ドラムに２５秒間押しつけて熱現像した試料の画像形成層が塗設されている面の表面にカミソリを用いて４ｍｍ間隔で縦横それぞれ６本ずつの傷を付けて、２５升の升目を作った。但し傷は支持体の表面に到達する深さで付けた。この上に幅２５ｍｍのマイラーテープを貼り付けて充分に圧着した。圧着後５分してから、マイラーテープを１８０度の剥離角で急激に引っ張って試料から剥離した。この時画像形成層が試料から剥離した升目の数を数え、
Ａ：剥離０升
【０１６７】
Ｂ：剥離が１升未満
Ｃ：剥離が５升未満
Ｄ：剥離が５升以上
で分類した。Ａ及びＢが実用上問題ないレベルである。
【０１６８】
（生保存性の評価）
上記で作製した熱現像材料を防湿袋に入れ、２３℃、５５％ＲＨで４時間調湿後２つに折半し、一方は調湿後直ちに上記露光、熱現像処理を行い、もう一方は５５℃で３日間防湿袋で加熱保存した後に同様に露光、熱現像処理を行った。得られた画像の評価（カブリ）を濃度計により行い、加熱処理したものと処理していないものの差を生保存性の尺度とした。このとき測定したカブリ濃度はベース濃度を差し引いた値である。
【０１６９】
表６に示すように下引済支持体の熱処理の有無、および画像形成層、バッキング層の塗布工程及び支持体の調湿における相対湿度を変化させることによって、表６に記載の熱現像材料を調製し、熱現像材料の熱寸法安定性、膜付き、生保存性を評価した。
【０１７０】
尚、支持体の含水率については熱寸法安定性、膜付き、生保存性の評価直前の熱現像前に測定した。尚、表６における徐冷とは、下引き層を塗布した支持体を１００℃、１０分で熱処理後、５分で７０℃になる速度で冷却後、室温まで放置して冷却する冷却操作を指す。またアニールは１００℃、１０分で熱処理後、支持体を室温になるまで放置し、その後６０℃で４０時間静置する熱処理を言う。評価した結果を表６に示す。
【０１７１】
【表６】

【０１７２】
表６から明らかなように、熱現像材料の支持体の含水率を０．５％以下にした場合、膜付きが良好で、耐熱寸法安定性、生保存性に優れていることがわかる。
【０１７３】
実施例５
次に画像形成層に添加する化合物の溶解に使用するメタノールを任意の比率で混合したメタノール／ＭＥＫに変更することで表７に示すように画像形成層中のメタノール比率を変化させた。また試料５−３、及び５−４については画像形成層塗布前に塗布液を乾燥剤（シリカゲル）に１時間接触させた。その他の条件は実施例４の試料４−１と同様にして作製し、評価を行った。
【０１７４】
結果を表７に示す。尚、生保存性については３日間の保存温度を６５℃とした。
【０１７５】
【表７】

【０１７６】
表７から明らかなように、熱現像材料の画像形成層の塗布液の含水率を２．０％以下にした場合、膜付きが良好で、耐熱寸法安定性、生保存性に優れている。
【０１７７】
実施例６
次に画像形成層の塗布後に表８に記載の条件で再乾燥を行い、また画像形成層の溶媒であるメチルエチルケトンとトルエンの比率を変更した他は、実施例４の熱現像材料４−１と同様にして熱現像材料を作製し、評価を行った。
【０１７８】
結果を表８に示す。尚、生保存性については保存期間を６日間とした。
【０１７９】
【表８】

【０１８０】
表８から明らかなように、熱現像材料を２３℃、５５％ＲＨに３時間放置したときの含水率を０．５％以下、溶媒残留率を２．０％以下にした場合、膜付きが良好で、耐熱寸法安定性、生保存性に優れている。
【０１８１】
【発明の効果】
本発明により、高感度で、製造時及び生保存時のカブリが低く、熱現像時に膜剥がれが生じなく、また耐熱寸法安定性に優れる熱現像材料を提供することができた。
【図面の簡単な説明】
【図１】放電処理を施す表面処理装置の概略構成図である。
【図２】別の表面処理装置の概略構成図である。
【符号の説明】
１ 支持体
２，３ 電極
４，５ 誘電体
６，７ 供給口
８ ニップローラ
９ 電源
１０ 表面処理装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-developable material that forms an image by heat development, and has high sensitivity, less fogging, improved raw storage, no film peeling during heat development, and excellent heat-resistant dimensional stability. The present invention relates to a heat-developable material and a method for producing the same.
[0002]
[Prior art]
Many thermal development processes in which the development process is performed by heating have been studied so far, and those that obtain black and white images and color images are known. In addition, a so-called transfer type heat developing material for transferring an image obtained by heat development to an image receiving layer is also well known.
[0003]
In recent years, waste liquids resulting from wet processing of image forming materials have become a problem in terms of workability in the fields of printing plate making and medical care. In recent years, the amount of waste processing waste has been strongly reduced from the viewpoint of environmental conservation and space saving. It is desired. Therefore, there is a need for a technique relating to a heat-developable material that can be efficiently exposed by a laser image setter or a laser imager and can form a clear black image with high resolution. For example, U.S. Pat. Nos. 3,152,904, 3,487,075 and D.I. The method described in “Dry Silver Photographic Materials” by Morgan (Handbook of Imaging Materials, Marcel Dekker, Inc., page 48, 1991) and the like is well known. These photosensitive materials are usually developed at a temperature of 80 ° C. or higher.
[0004]
Such a heat-developable material usually contains a reducible silver source (for example, an organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), and a reducing agent dispersed in an organic binder matrix. However, when heated to a high temperature after exposure, silver is generated by a redox reaction between a reducible silver source (acting as an oxidizing agent) and the reducing agent. This redox reaction is promoted by the catalytic action of the latent image generated by exposure. The 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.
[0005]
[Problems to be solved by the invention]
By the way, conventionally, most of this type of heat developing material forms each layer including an image forming layer by applying a coating solution using an organic solvent such as methyl ethyl ketone or methanol to a support. These solvents are highly miscible with water, and moisture is inevitably mixed due to condensation during the production of the coating solution. The organic silver salt also retains moisture according to the dry state, and since it is a heat-developable material, it is difficult to sufficiently dry at a high temperature after coating, not only moisture in the developing material after drying, The present condition is that the organic solvent also remains. Moisture remaining in these coating solutions and materials dissociates silver ions from organic silver salts such as silver behenate, promotes reaction with the contained reducing agent, and induces fogging during production and raw storage. It turned out to be one of the major causes.
[0006]
In addition, when the heat-developable material thus prepared is actually developed at a temperature of 80 to 150 ° C., the film may be peeled off due to thermal shrinkage and a decrease in elastic modulus of the support and binder. It was a problem.
[0007]
In order to eliminate film peeling at the time of heat development of the heat development material, it is generally known to use a film support and a binder composed of a thermoplastic resin having a glass transition point higher than the heat development temperature. This uses a film support composed of a thermoplastic resin having a glass transition point higher than the heat development temperature and a thermoplastic resin binder, and suppresses thermal shrinkage (deformation) and a decrease in elastic modulus due to heat, thereby peeling off the film. Is to prevent. However, it has been found that even when a thermoplastic resin having a glass transition point higher than the heat development temperature is used, film peeling occurs.
[0008]
    The present invention has been made in view of the above circumstances, and an object of the present invention is to firstly provide a heat-developable material having high sensitivity and low fog at the time of production and raw storage. An object of the present invention is to provide a heat-developable material that does not peel off during development and has excellent heat-resistant dimensional stability and small thermal dimensional change.
  In addition, as a result of intensive studies, the present inventors have found that the moisture and residual solvent in the film support and binder play a role as a plasticizer during heat development, and the film support and binder are thermally contracted (deformed) and elastic modulus due to heat. It has been found that film peeling occurs. Therefore, not only the water content and / or residual solvent ratio of the heat-developable material, but also the water content of the film support and the coating solution at the time of coating is controlled in the photothermographic material coated with a coating solution using an organic solvent. Thus, it has been found that a photothermographic material that does not peel off during heat development, has excellent heat-resistant dimensional stability, and has a small heat dimensional change is obtained.
[0009]
[Means for Solving the Problems]
  Therefore, the above object of the present invention is achieved by the following.
  1. A heat-developable material having an image forming layer on a support and having an equilibrium water content of 3% by mass or less at 25 ° C. and 60% RH,Moisture removed when in contact with desiccantIt is a layer formed by applying and drying a coating solution using at least one selected from the following water-miscible solvents, and the support is heat-treated or discharged when the coating solution is applied. A heat-developable material, wherein the water content of the support is 0.33% by mass or less.
  Water miscible solvents: acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, butanol, tetrahydrofuran, dioxane, dioxolane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone
  2. 2. The heat developing material as described in 1 above, wherein the image forming layer contains an organic silver salt and photosensitive silver halide grains.
  3. 2. The heat developable material as described in 1 above, wherein the water-miscible solvent is methyl ethyl ketone.
  4). 3. The method for producing a heat developing material according to 1 or 2, wherein the residual solvent ratio of the heat developing material after drying is 2.0% by mass or less.
[0012]
  The present invention will be described in detail below.
  The “equilibrium moisture content (D) at 25 ° C. and 60% RH” in the present invention means the mass W of the heat-developable material in a humidity-controlled equilibrium under an atmosphere of 25 ° C. and 60% RH and the heat-developable material. Using moisture content w
      D (mass%) = (w / W) × 100
It is represented by
[0013]
  In the present invention, it is necessary that the equilibrium water content of the heat-developable material at 25 ° C. and 60% RH be 3% by mass or less, preferably 0.005% by mass to 2% by mass, and more preferably 0%. It is 0.01 mass% or more and 1 mass% or less.
[0014]
  The “moisture content (F)” in the present invention is determined by using the mass Z of the coating solution and the moisture content z of the coating solution.
      F (mass%) = (z / Z) × 100
It is represented by
[0015]
In order to obtain the heat-developable material of the present invention, the moisture content of the coating solution is preferably 3% by mass or less, more preferably 0.01% by mass to 2% by mass, and still more preferably 0.02% by mass. The content is 1% by mass or less.
[0016]
The actual measurement of the equilibrium moisture content and moisture content can be performed as shown in the examples below.
[0017]
  There are roughly two means for preparing a coating solution having a moisture content of 3% by mass or less, and one is to use an organic solvent having a water solubility of 3% by mass or less. Specific examples thereof include benzene, toluene, xylene, hexane, cyclohexane, diethyl ether, diisopropyl ether, hydrofluoroether, methylene chloride, chloroform, trichloroethylene and the like. In addition, the organic solvent whose water solubility is 3 mass% or less may be used individually or in multiple types. Furthermore, it may be used in combination with a water-miscible solvent described below as long as the moisture content of the coating solution satisfies the condition of 3% by mass or less.
[0018]
The other one is a method in which a water-miscible solvent is used and the coating solution is prepared and applied in an inert gas atmosphere such as dry nitrogen gas, or a water-miscible solvent is used. There is a method of removing water by contacting the liquid with a desiccant. The water-miscible solvent here refers to an organic solvent having a water solubility of more than 3% by mass. Specific examples include acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, butanol, tetrahydrofuran, dioxane, dioxolane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and methyl ethyl ketone is preferred.
[0019]
In addition, the desiccant excluding moisture is not particularly limited as long as moisture is removed by contact, but examples include silica gel, molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, pure iron, and iron compounds. More preferably, it is silica gel.
[0020]
Among the methods described above, as a method for reliably removing moisture, a method of removing moisture by bringing a coating solution prepared using a water-miscible solvent into contact with a desiccant is most preferable.
[0021]
  In the present invention, the water content of the coating solution containing an organic silver salt, photosensitive silver halide grains and a reducing agent for coating the image forming layer is from 5 g to 50 g, preferably from 5 g to 1 g. 40 g, and further 5 g to 20 g. The water content here can be measured by the Karl Fischer method with reference to “Method of measuring moisture of chemical product” (JIS K 0068). In order to control in this way, nitrogen replacement may be performed by setting 50% or more, preferably 80% or more, and further 90% or more of the time required for preparing the coating liquid to be in a nitrogen atmosphere.
[0022]
Of the moisture contained in the coating solution, the moisture contained in the organic silver salt is desirably 5% by mass or less, preferably 3% by mass or less, and further 2% by mass or less. When the ratio of moisture brought in from the organic silver salt is high, the ratio of silver ions in the organic silver salt increases, which causes an increase in fog and a change in sensitivity.
[0023]
  The support used for the heat-developable material of the present invention must have an equilibrium water content of 0.5% by mass or less at 25 ° C. and 60% RH so that moisture does not bleed from the support to the image forming layer. It is preferable that it is 0.01-0.5 mass%, Most preferably, it is 0.3 mass% or less.
[0024]
The water content of the support must be controlled before applying a coating solution containing at least an organic silver salt, a photosensitive silver halide and a reducing agent. This is because it is necessary to perform heat treatment at 100 ° C. or higher for a long time in order to remove moisture from the support after coating.
[0025]
  BookThe invention is to set the moisture content of the uncoated support to 0.5% by mass or less, and as a specific method thereof, (1) at least an organic silver salt, a photosensitive silver halide and a reducing agent are used. The support is heat-treated at 100 ° C. or more immediately before coating the coating solution containing it. (2) Controlling the relative humidity in the step of coating the coating solution containing at least an organic silver salt, a photosensitive silver halide and a reducing agent. (3) Before applying a coating solution containing at least an organic silver salt, a photosensitive silver halide and a reducing agent, the support is heat-treated at 100 ° C. or more, covered with a moisture-proof sheet, stored, and applied immediately after opening. And so on. Two or more of these may be combined. Moreover, (2) and (3) are preferable from the restrictions on the process.
[0026]
  BookThe moisture content of the support in the invention is that when the humidity is adjusted for 3 hours in an atmosphere of 23 ° C. and 20% RH.
[0027]
As the support used in the photothermographic material of the present invention, any type of polymer may be used as long as it satisfies the above equilibrium water content and water content. The following excellent polymers are preferably used.
[0028]
Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAr), polyetheretherketone (PEEK), polysulfone (PSO), polyimide (PI), poly Ether imide (PEI), polyamide (PAm), polystyrene (PS), syndiotactic polystyrene (SPS) and the like.
[0029]
These polymers may be used in a single layer or a laminate, or may be used in copolymers and polymer blends based on these. Of these, PET, PEN and PC are substantially preferred for use as a support in the present invention, and more preferably PET and PEN are substantially preferred. The term “substantially PET and PEN” as used herein may refer to a copolymer and a polymer blend, and refers to those having a mass ratio of the constituent elements of PET and PEN to 50% by mass or more.
[0030]
PET and PEN are composed of terephthalic acid or naphthalene dicarboxylic acid and ethylene glycol, and can be polymerized by combining them under appropriate reaction conditions in the presence of a catalyst. At this time, you may mix an appropriate 1 type, or 2 or more types of 3rd component. However, those in which sulfonic acid groups or hydroxyl groups remain after polymerization are not preferred.
[0031]
The method for synthesizing PET and PEN used for the support in the present invention is not particularly limited, and can be produced according to conventionally known methods for producing PET and PEN. For example, a direct esterification method in which a dicarboxylic acid component is directly esterified with a diol component, or a dialkyl ester is first used as the dicarboxylic acid component, and this is transesterified with the diol component, and then heated under reduced pressure. Thus, a transesterification method in which polymerization is performed by removing excess diol component can be used. At this time, if necessary, a transesterification catalyst or a polymerization reaction catalyst can be used, or a heat-resistant stabilizer can be added. In addition, coloring agents, antioxidants, crystal nucleating agents, slipping agents, stabilizers, anti-blocking agents, UV absorbers, viscosity modifiers, antistatic agents, dyes, pigments, etc. are added during each process during synthesis. Also good.
[0032]
In the present invention, the support can be provided with easy slipperiness if necessary. The slipperiness imparting means is not particularly limited, but an external particle addition method for adding inert inorganic particles, an internal particle precipitation method for precipitating a catalyst added at the time of polymer polymerization, or a surfactant is applied to the film surface. The method of doing is common. Among these, the internal particle precipitation method capable of controlling the precipitated particles to be relatively small is preferable because it can provide easy slipping without impairing the transparency of the film.
[0033]
The thickness of the support used in the present invention is not particularly limited. What is necessary is just to set so that it may have required intensity | strength according to the use purpose. In particular, when used for a medical or printing photographic light-sensitive material, the thickness is preferably 50 to 250 μm, and particularly preferably 70 to 200 μm.
[0034]
In addition, the support used in the present invention preferably has a haze of 3% or less. More preferably, it is 1% or less. If the haze is greater than 3%, the image tends to be unclear when the film is used as a support for a photographic material. The haze is measured according to ASTM-D1003-52.
[0035]
The support used in the present invention is a heat treatment at a temperature below Tg as described in US Pat. No. 4,141,735, as described in JP-A Nos. 9-218486, 9-281650 and 10-103944. By performing a heat treatment while cooling so as to pass through the temperature range of Tg + 25 ° C. to Tg + 5 ° C. over 20 seconds to 300 seconds, it is possible to make it difficult to cause curl.
[0036]
In the present invention, it is preferable to provide an undercoat layer on the support before coating with a coating solution containing at least an organic silver salt, a photosensitive silver halide and a reducing agent. To be improved.
[0037]
The undercoat layer may be applied during film formation of the film support or may be applied off-line after film formation. The conditions for coating the undercoat layer are preferably dried and heat-treated at a temperature of 100 ° C. or more for 1 minute or more in order to greatly contribute to the moisture content when the heat-developable image forming layer is applied.
[0038]
As the resin constituting the undercoat layer, polyester, acrylic modified polyester, polyurethane, acrylic resin, vinyl resin, vinylidene chloride resin, polyethyleneimine vinylidene resin, polyethyleneimine, polyvinyl alcohol, modified polyvinyl alcohol, gelatin and the like are preferable. In particular, polyester, acrylic-modified polyester, polyurethane, and acrylic resin are preferable in terms of adhesion to the heat-developable image forming layer.
[0039]
In the present invention, after applying a coating solution containing at least an organic silver salt, a photosensitive silver halide and a reducing agent, the temperature is 40 to 120 ° C., preferably 50 to 100 ° C., more preferably 60 to 80 ° C., and the tension is 0. .01-30kg / m², Preferably 1.0-20 kg / m²And 5-10kg / m²And drying or heat treatment may be performed. If the temperature is too constant, fogging may occur, and it is preferable that the tension is low if transportability is obtained.
[0040]
The coating method can be applied by various coating methods including dip coating, air knife coating, flow coating, or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. Stephan F. Kister, M.C. Extrusion coating, slide coating, and curtain coating methods described in pages 399 to 734 of “LIQUID FILM COATING” (CHAPMA & HALL, 1997) by Schwezer can also be employed. Further, if desired, U.S. Pat. Nos. 2,761,791, 3,508,947, 2,941,898, 3,526,528 and Yuji Harasaki "Coating Engineering", page 253 (1973) Two or more layers can be applied at the same time by the method described in Asakura Publishing Co., Ltd.).
[0041]
In the present invention of (6), the residual solvent ratio of the produced heat developing material is 2.0% by mass or less, but preferably 1.0% by mass or less. In order to reduce the residual solvent ratio to 2.0% by mass or less, the coating solution is dried again after coating and drying at a temperature range of 40 to 80 ° C. for 1 to 20 minutes, and the boiling point of the organic solvent to be used is 85 ° C. or less. There is a way to make it. Examples of such a solvent include methyl ethyl ketone, benzene, hexane, cyclohexane, diethyl ether, chloroform, methanol, ethanol, isopropanol, and the residual solvent ratio.
Residual solvent ratio = (mass of residual volatile matter / film mass after heat treatment) × 100%
It is represented by The residual volatile matter mass is a value obtained by subtracting the film mass after the heat treatment from the film mass before the heat treatment when the photothermographic material is heat-treated at 115 ° C. for 1 hour.
[0042]
Moreover, it is effective in prevention of film peeling that the at least one side of a support body is discharge-processed.
[0043]
An embodiment of the discharge treatment will be described with reference to FIG. 1 which is a schematic configuration diagram of a surface treatment apparatus 10 that performs the discharge treatment.
[0044]
In FIG. 1a, the support 1 that is continuously transported between the pair of electrodes 2 and 3 by a transport means (not shown) is preferably a polymer support, and more preferably various polyester supports such as PET and PEN. Yes, it is used for the production of photosensitive materials. Between the pair of electrodes 2 and 3 to which the support 1 is transported, an inert gas (preferably argon, which will be described as argon hereinafter) contained at least 50% by pressure at or near atmospheric pressure. The atmosphere is gas. In addition to argon, this gas atmosphere may contain oxygen, nitrogen, carbon dioxide, helium, ketone, hydrocarbon-containing gas, or water vapor. In particular, a gas containing oxygen, nitrogen, carbon dioxide, a ketone or a gas containing water or water vapor can be chemically reformed and the film-attaching property can be improved. This gas is supplied between the pair of electrodes 2 and 3 by a supply means (not shown) to keep the atmosphere.
[0045]
The pair of electrodes 2 and 3 can be a flat plate electrode (FIG. 1a), a cylindrical electrode (FIG. 1b) in which a plurality of cylindrical electrodes are arranged, or a roll electrode (FIG. 1c, FIG. 1d, FIG. 1e), which is formed of a conductive member, for example, a metal such as stainless steel, aluminum, or copper, and a dielectric (for example, ceramic), and a dielectric is provided on at least the opposing surfaces of the pair of electrodes 2 and 3 4, 5 are provided. A plurality of the electrodes may be arranged in parallel. The thickness of the dielectric is preferably around 0.53 mm, but the appropriate point varies depending on the material, the distance between the electrodes, the support, the mixed gas, the power source, and the like. The gap between the pair of electrodes 2 and 3 is set to be 10 mm or less. Further, supply ports 6 and 7 are provided between the electrodes so as to introduce the mixed gas. In general, there are a plurality of supply ports for the uniform introduction of gas, and the position may be in the electrode, but may be provided in other locations. Further, by connecting a power source 9 having a frequency of 1 kHz or more and 100 kHz or less, preferably 1 kHz or more and 10 kHz or less, to the pair of electrodes 2 and 3, discharge is generated between the pair of electrodes 2 and 3.
[0046]
A pair of electrodes having a gas atmosphere containing at least 50% by pressure of argon at atmospheric pressure or in the vicinity thereof with respect to the surface (both sides in the present embodiment) of the support 1 being continuously conveyed in this way. By performing discharge between two and three, the film attachment property can be improved. In addition, since a gas containing at least 50% by pressure of argon, which is cheaper than helium, is used, the running cost can be reduced. In addition, by using argon, the molecular weight thereof is larger than that of helium, so that the edging effect of striking the surface of the support 1 to give unevenness is excellent, so that the film-attachability can be further improved. Furthermore, by setting the gap between the pair of electrodes 2 and 3 to 10 mm or less, stable discharge can be generated.
[0047]
Further, one or more spare chambers are formed on the entrance side where the support 1 enters between the pair of electrodes 2 and 3, and a pair of nip rollers 8 for partitioning the chambers are provided. The pair of nip rollers or more serve as a preventing means for preventing the accompanying air accompanying the conveyance of the support 1 from entering between the pair of electrodes 2 and 3, whereby the accompanying air enters between the pair of electrodes 2 and 3. Without changing the gas concentration, stable discharge is possible. As this prevention means, an air blade using the same gas as the atmosphere between the electrodes 2 and 3 may be used.
[0048]
Further, when the conveying direction of the support 1 is set to the vertical direction, it is advantageous to maintain a gap between the pair of electrodes 2 and 3 without impairing the flatness of each of the pair of electrodes 2 and 3 which are flat plate electrodes. .
[0049]
Moreover, as shown in FIG. 2, you may provide multiple surface treatment apparatuses 10 mentioned above.
The silver halide grains function as an optical sensor. In order to suppress white turbidity after image formation and to obtain a good image quality, it is preferable that the average particle size is small, the average particle size is 0.1 μm or less, more preferably 0.01 μm to 0.1 μm, and particularly preferably 0. 02 μm to 0.08 μm is preferable. The grain size here refers to 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, it means the diameter when a sphere equivalent to the volume of silver halide grains is considered. The silver halide is preferably monodispersed. Monodispersion here means
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100
The monodispersion degree calculated | required by said 40% or less. The particles are more preferably 30% or less, particularly preferably 0.1% or more and 20% or less.
[0050]
The shape of the 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, particularly 80% or more. Is preferred. Another preferred silver halide shape is a 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 preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.08 μm. These are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958 and the like, and the desired tabular grains can be easily obtained.
[0051]
The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. The photographic emulsion used in the present invention is P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared using a method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al. The silver halide may be added to the image forming layer by any method, and at this time, the silver halide is disposed close to the reducible silver source. Further, the silver halide may be prepared by converting a part or all of silver in the organic acid silver to silver halide by the reaction between the organic acid silver and the halogen ion, or the silver halide is prepared in advance. This may be added to the solution for preparing the organic silver salt, or a combination of these methods is possible, but the latter is preferred. In general, the silver halide is preferably contained in an amount of 0.75 to 30% by mass relative to the organic silver salt.
[0052]
The silver halide used in the present invention preferably contains metal ions or complex ions belonging to Groups 6 to 10 of the Periodic Table of Elements in order to improve the illuminance failure and adjust the gradation. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable.
[0053]
The photosensitive silver halide grains can be desalted by washing with water by a method known in the art such as a noodle method or a flocculation method.
[0054]
The photosensitive silver halide grains in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization methods such as gold compounds, platinum, palladium, and iridium compounds, as well known in the art, and reduction sensitization. Sensitive methods can be used.
[0055]
Organic silver salt is a reducible silver source, silver salts of organic acids and heteroorganic acids containing a reducible silver ion source, especially long chains (10-30, preferably 15-25 carbon atoms). Aliphatic carboxylic acids and nitrogen-containing heterocycles are preferred. Also useful are organic or inorganic silver salt complexes in which the ligand has a total stability constant for silver ions of 4.0-10.0. Examples of suitable silver salts are described in Research Disclosure Nos. 17029 and 29963. Among them, a preferable silver source is silver behenate, silver arachidate, or silver stearate.
[0056]
The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver. As described in Japanese Patent Application Laid-Open No. 9-127643, a normal mixing method, a reverse mixing method, and a simultaneous mixing method are used. A controlled double jet method or the like is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.), and then controlled double jet. The soap and silver nitrate are added to produce organic silver salt crystals. At that time, silver halide grains may be mixed.
[0057]
In the present invention, the organic silver salt preferably has an average particle size of 2 μm or less and is monodispersed. The average particle diameter is preferably 0.05 μm to 1.5 μm, particularly preferably 0.05 μm to 1.0 μm. The monodispersity is preferably 1-30. In the present invention, the organic silver salt preferably has tabular grains of 60% or more of the total organic silver. Tabular grains are those having an aspect ratio of 3 or more.
[0058]
These forms of organic silver can be obtained by dispersing and grinding the organic silver crystals with a binder, a surfactant, or the like using a ball mill or the like.
[0059]
In the present invention, in order to prevent devitrification of the light-sensitive material, the total amount of silver halide and organic silver salt is 1 m in terms of silver amount.²It is preferably 0.5 g or more and 2.2 g or less. By setting this range, a high-contrast image can be obtained. The amount of silver halide based on the total amount of silver is 50% or less, preferably 25% or less, and more preferably 0.1% to 15% by mass ratio.
[0060]
Examples of reducing agents suitable for the heat development material of the present invention are described in U.S. Pat. Nos. 3,770,448, 3,773,512, 3,593,863, and Research Disclosure Nos. 17029 and 29963. Has been. Of these, particularly preferred reducing agents are hindered phenols. Examples of the hindered phenols include compounds represented by the following general formula (A).
[0061]
[Chemical 1]

[0062]
In the formula, R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (for example, -C_FourH₉2,4,4-trimethylpentyl), R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (for example, methyl, ethyl, t-butyl).
[0063]
Specific examples of the compound represented by formula (A) are shown below. However, the present invention is not limited to the following compounds.
[0064]
[Chemical formula 2]

[0065]
[Chemical Formula 3]

[0066]
The amount of reducing agent used, including the compound represented by the general formula (A), is preferably 1 × 10 5 per mole of silver.^-2-10 mol, especially 1 x 10^-2~ 1.5 mol.
[0067]
Binders suitable for the heat-developable photographic light-sensitive material of the present invention are transparent or translucent and generally colorless, and are natural polymers, synthetic resins, polymers and copolymers, and other media forming films such as gelatin, gum arabic, poly ( Vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters) , Poly (ureta ), Phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. It may be hydrophilic or hydrophobic. In order to protect the surface of the photosensitive material and prevent scratches, a non-photosensitive layer can be provided outside the image forming layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the image forming layer.
[0068]
In the present invention, the binder amount of the image forming layer is 1.5 to 10 g / m in order to increase the speed of heat development.²It is preferable that More preferably 1.7 to 8 g / m²It is.
[0069]
In the present invention, it is preferable to contain a matting agent on the image forming layer side, and in order to prevent damage to the image after heat development, it is preferable to dispose the matting agent on the surface of the photosensitive material. It is preferable to contain 0.5-30% by mass ratio with respect to the total binder on the image forming layer side.
[0070]
The material of the matting agent used in the present invention may be either organic or inorganic. 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 particle size of the matting agent indicates a sphere-converted diameter, and the average particle size is preferably 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. or,
(Standard deviation of particle size) / (Average value of particle size) × 100
Is preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less. The matting agent can be contained in any constituent layer, but is preferably a constituent layer other than the photosensitive layer, and more preferably the outermost layer as viewed from the support. The method for adding the matting agent may be a method in which the matting agent is dispersed and applied in advance, or a method in which the matting agent is sprayed after the coating solution is applied and before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination.
[0071]
The photothermographic material of the present invention has at least one photosensitive image forming layer on a support. Although only the image forming layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the image forming layer. In order to control the amount of light passing through the image forming layer or the wavelength distribution, a filter dye layer on the same side as the layer and / or an antihalation dye layer, a so-called backing layer, on the opposite side may be formed. A dye or pigment may be included in the layer. The dye to be used may be any compound as long as it has the desired absorption in a desired wavelength range.
[0072]
These non-photosensitive layers preferably contain the binder and matting agent described above, and may further contain a polysiloxane compound, a slipping agent such as wax or liquid paraffin.
[0073]
The image forming layer may be 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 adjusting the gradation.
[0074]
The heat-developable material of the present invention contains an organic silver salt, a photosensitive silver halide, a reducing agent and, if necessary, a toning agent that suppresses the tone of silver in a dispersed state in a normal (organic) binder matrix. It is preferable.
[0075]
The toning agent participates in the oxidation-reduction reaction between the organic silver salt and the reducing agent, and has a function of making the resulting silver image dark, particularly black. Examples of suitable toning agents for use in the present invention are disclosed in Research Disclosure No. 17029. Particularly preferred toning agents are phthalazone or phthalazine.
[0076]
In the present invention, a mercapto compound, a disulfide compound, and a thione compound can be contained in order to suppress or promote development and control development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. .
[0077]
The photothermographic material of the present invention may contain an antifogging agent. Mercury ions are known as the most effective antifoggants. 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, mercury compounds are environmentally undesirable. As the non-mercury antifogging agent, for example, antifogging agents as disclosed in US Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234 are preferable.
[0078]
Examples of the heat developing material of the present 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, US Pat. No. 4,639,414, No. 4,740,455, No. 4,741,966, No. 4,751,175, No. 4,835,096 Can be used. Useful sensitizing dyes 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) and Item 1831X (August 1978, p.437). Has been. 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.
[0079]
In the heat-developable material of the present invention, a hydrazine compound may be contained in the light-sensitive material for the purpose of enhancing the image contrast. Preferred hydrazine compounds used in the present invention include Research Disclosure Item 23515 (November 1983, P. 346) and the literature cited therein, U.S. Pat. No. 4,080,207, 4, No. 269,929, No. 4,276,364, No. 4,278,748, No. 4,385,108, No. 4,459,347, No. 4,478,928, 4,560,638, 4,686,167, 4,912,016, 4,988,604, 4,994,365, 5,041 No. 5,355, No. 5,104,769, British Patent No. 2,011,391B, European Patent Nos. 217,310, 301,799, 356,898, JP-A-60- 17 No. 734, No. 61-170733, No. 61-270744, No. 62-178246, No. 62-270948, No. 63-29751, No. 63-32538, No. 63-104047, No. 63-121838 63-129337, 63-223744, 63-234244, 63-234245, 63-234246, 63-294552, 63-306438, 64-10233, Special Kaihei 1-90439, 1-100530, 1-105941, 1-105943, 1-276128, 1-280747, 1-283548, 1-283549, 1 -285940, 2-2541, 2-77057, 2-139538, 2-19623 No. 2-196235, No. 2-198440, No. 2-198441, No. 2-198442, No. 22-220042, No. 22-221953, No. 2-221154, No. 2-285342, 2-285343, 2-28943, 2-302750, 2-304550, 3-37642, 3-54549, 3-125134, 3-184039, 3 -240036, 3-240037, 3-259240, 3-280038, 3-282536, 4-511436, 4-56842, 4-84134, 2-230233 No. 4-96053, No. 4-216544, No. 5-45761, No. 5-45762, No. 5-45763, No. 5-45764, Examples described in JP-A-5-45765, JP-A-6-289524, JP-A-9-160164, and the like can be given.
[0080]
In addition, compounds represented by (Chemical formula 1) described in JP-B-6-77138, specifically, compounds described on pages 3 and 4 of the same publication, JP-B-6-93082 Specific examples of the compound represented by the general formula (1) described above include compounds 1 to 38 described on pages 8 to 18 of the same publication, general formula (4) described in JP-A-6-23049, Compounds represented by (5) and (6), specifically, compounds 4-1 to 4-10 described on pages 25 and 26 of the same publication, compounds 5-1 to pages 28 to 36 5-42, and compounds 6-1 to 6-7 described on pages 39 and 40, and compounds represented by general formulas (1) and (2) described in JP-A-6-289520, Are described in compounds 1-1) to 1-17) and 2-1) described in pages 5 to 7 of the same publication, and JP-A-6-313936. Compounds represented by (Chemical Formula 2) and (Chemical Formula 3), specifically, compounds described on pages 6 to 19 of the same publication, compounds represented by (Chemical formula 1) described in JP-A-6-313951 Specifically, compounds described on pages 3 to 5 of the publication, compounds represented by general formula (I) described in JP-A-7-5610, and specifically, page 5 of the publication. To compounds 10-1 to I-38 described on page 10 and compounds represented by general formula (II) described in JP-A-7-77783, specifically described on pages 10-27 of the same publication. Compounds II-1 to II-102, compounds represented by general formula (H) and general formula (Ha) described in JP-A-7-104426, specifically, pages 8 to 15 Those described in the described compounds H-1 to H-44 can be used.
[0081]
Various additives may be added to any of the image forming layer, the non-photosensitive layer, and other forming layers. For example, surfactants, antioxidants, stabilizers, plasticizers, ultraviolet absorbers, coating aids, and the like may be used in the heat developing material of the present invention. As these additives and the other additives described above, compounds described in Research Disclosure Item 17029 (June 1978, p. 9-15) can be preferably used.
[0082]
For the exposure of the heat-developable material of the present invention, an argon ion laser (488 nm), a He—Ne laser (633 nm), a red semiconductor laser (670 nm), an infrared semiconductor laser (780 nm, 820 nm) or the like is preferably used. Infrared semiconductor lasers are more preferably used from the viewpoints of high power and that the photosensitive material can be made transparent.
[0083]
The exposure is preferably performed by laser scanning exposure, but it is preferable to use a laser scanning exposure machine in which the angle formed between the exposure surface of the photosensitive material and the scanning laser light is not substantially perpendicular. Here, “substantially not perpendicular” means that the angle closest to the vertical during laser scanning is preferably 55 ° to 88 °, more preferably 60 ° to 86 °, and even more preferably 65 °. It is at least 84 degrees and most preferably 70 degrees to 82 degrees.
[0084]
The beam spot diameter on the exposure surface of the photosensitive material when the laser beam is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that a smaller spot diameter can reduce the angle of deviation of the laser incident angle from the vertical. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.
[0085]
The exposure is also preferably performed using a laser scanning exposure machine that emits a scanning laser beam that is a vertical multi. Compared with a single longitudinal mode scanning laser beam, image quality degradation such as generation of interference fringe-like unevenness is reduced. In order to make it vertically multi-ply, a method such as using return light by combining or applying high-frequency superposition is preferable. The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.
[0086]
The photothermographic material of the present invention is stable at room temperature, but is developed by heating to a high temperature after exposure. The heating temperature is preferably 80 ° C. or higher and 200 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower. When the heating temperature is 80 ° C. or lower, sufficient image density cannot be obtained in a short time. When the heating temperature is 200 ° C. or higher, the binder is melted, and not only the image itself, such as transfer to a roller, but also adversely affects the transportability and the developing machine. Effect. The treatment time is preferably 5 seconds or more and 60 seconds or less, and more preferably 8 seconds or more and 30 seconds or less. When the processing time is 5 seconds or less, density unevenness due to processing tends to occur. In addition, fogging or deformation of the support tends to occur for 60 seconds or more. By heating, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (which functions as an oxidizing agent) and a reducing agent. This reaction process proceeds without supplying a treatment liquid such as water from the outside.
[0087]
It is preferable that the optical transmission density of the heat developing material including the support at 400 nm after the heat development treatment is 0.2 or less. A more preferable value of the optical transmission density is 0.02 or more and 0.2 or less.
[0088]
【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.
[0089]
  referenceExample 1
  [Preparation of a sublimed support]
  8 W / m on both sides of 120 μm thick polyethylene terephthalate support²・ Corona discharge treatment was applied for one minute, and the following undercoat coating liquid 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 the other side The undercoat coating solution b-1 shown below was coated on the surface so as to have a dry film thickness of 0.8 μm and dried to form an undercoat layer B-1.
[0090]

Subsequently, 8 W / m on the upper surface of the undercoat layer A-1 and the undercoat layer B-1.²The 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 layer A-2 so that the dry film thickness was 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.
[0091]
<< Undercoating upper layer coating liquid a-2 >>
Gelatin 0.4g / m²Amount to be
(C-1) 0.2g
(C-2) 0.2g
(C-3) 0.1 g
Silica particles (average particle size 3μm) 0.1g
Finish to 1 liter 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 (weight average molecular weight 600) 6g
Finish to 1 liter with water
[0092]
[Formula 4]

[0093]
[Chemical formula 5]

[0094]
(Preparation of silver halide 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 35 ° 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 An aqueous solution containing potassium and potassium iodide and rhodium chloride is added at 1 × 10 5 per silver mole.^-FourMole was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. 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 0.06 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 precipitated using a gelatin flocculant, desalted and then added with 0.1 g of phenoxyethanol to adjust the pH to 5.9 and pAg 7.5 to obtain a silver halide emulsion A.
[0095]
According to the method of Example 1 of JP-A-9-127643, silver behenate was prepared by the following method.
[0096]
(Preparation of Na behenate solution)
34 g of behenic acid was dissolved in 340 ml of isopropanol at 65 ° C. Next, a 0.25N aqueous sodium hydroxide solution was added with stirring to pH 8.7. At this time, about 400 ml of sodium hydroxide aqueous solution was required. Next, this aqueous solution of sodium behenate was concentrated under reduced pressure to make the concentration of sodium behenate 8.9% by mass.
[0097]
(Preparation of silver behenate)
A 2.94 M silver nitrate solution was added to a solution of 30 g ossein gelatin dissolved in 750 ml distilled water to adjust the silver potential to 400 mV. Into this, 374 ml of the sodium behenate solution was added at a speed of 44.6 ml / min at a temperature of 78 ° C. using a controlled double jet method, and at the same time, a 2.94 M silver nitrate aqueous solution was added so that the silver potential became 400 mV. Added. The amounts of sodium behenate and silver nitrate used at the time of addition were 0.092 mol and 0.101 mol, respectively.
[0098]
After completion of the addition, the mixture was further stirred for 30 minutes, and water-soluble salts were removed by ultrafiltration.
(Preparation of photosensitive emulsion A)
To this silver behenate dispersion, 0.01 mol of the above silver halide emulsion A was added, and 100 g of an n-butyl acetate solution of polyvinyl acetate (1.2% by mass) was gradually added while stirring. After forming water flocs, water was removed, water was washed twice and water was removed, and then a 1: 2 mixture of 2.5% by weight of butyl acetate and isopropyl alcohol in polyvinyl butyral (average molecular weight 3000) as a binder. After adding 60 g of the solution with stirring, polyvinyl butyral (average molecular weight 4000) and the solvent shown in Table 1 were added and dispersed as a binder to the gel-like mixture of behenic acid and silver halide thus obtained. Was prepared.
[0099]
The following layers were sequentially formed on the support with the undercoat layer as described above to prepare a sample. The drying was performed at 75 ° C. for 5 minutes.
[0100]
(Back side application)
Polyvinyl butyral 8g / m²
Dye-B 70 mg / m²
Dye-C 70 mg / m²
A coating solution prepared by adding a composition consisting of the above to a solvent shown in Table 1 was applied to a wet thickness of 80 microns.
[0101]
[Chemical 6]

[0102]
(Image-forming layer side coating)
Image forming layer 1: The following composition is coated with a silver amount of 2.0 g / m²8g / m of polyvinyl butyral as a binder²In addition to the solvents listed in Table 1, a coating solution was prepared and coated and dried.
[0103]

[0104]
[Chemical 7]

[0105]
Surface protective layer: A coating solution prepared by adding the following composition to the solvent shown in Table 1 was applied and dried on each image forming layer so as to have a wet thickness of 100 μm.
[0106]
Cellulose acetate 8.0g / m²
Phthalazine 1.0g / m²
4-methylphthalic acid 0.72 g / m²
Tetrachlorophthalic acid 0.22g / m²
Tetrachlorophthalic anhydride 0.5g / m²
Silica matting agent (average particle size 5 μm) 0.5 g / m²
In addition, those which are difficult to dissolve in the solvents shown in Table 1 were dissolved using a small amount of a solubilizing solvent such as dimethylformamide (DMF) or added in solid dispersion in the solvents shown in Table 1.
[0107]
<Measurement of equilibrium moisture content of heat-developable materials>
The resulting heat-developable material was conditioned for 24 hours in an environment of 25 ° C. and 60% RH, and then the film area was 46.3 cm under the same atmosphere.²After cutting out and measuring the mass, this was finely cut to about 5 mm, housed in a dedicated vial, sealed with a septum and an aluminum cap, and then set in a head space sampler HP7694 manufactured by Hewlett-Packard. Headspace sampler heating condition: moisture evaporated in 120 minutes at 120 ° C. was quantified by the Karl Fischer method.
[0108]
<Evaluation of photographic performance>
The heat-developable material produced above was split in half, and one was exposed with a laser sensitometer having a semiconductor laser with a wavelength of 780 nm. Thereafter, heat development was performed at 130 ° C. for 25 seconds using a heat drum. At that time, exposure and development were performed in a room conditioned at 25 ° C. and 60% RH. Evaluation of the obtained image (sensitivity, fog and maximum density (Dmax)) was performed with a densitometer (room temperature photographic property). The sensitivity was evaluated by the reciprocal of the ratio of the exposure amount giving a density 0.3 higher than the fog (minimum) density (Dmin). It was expressed by relative evaluation with 1 as a reference. The angle between the exposure surface of the heat developing material and the exposure laser beam was 80 degrees. The above measurement was performed after placing the heat developing material in an atmosphere of 25 ° C. and 60% RH for 24 hours. The rest was divided into a plurality of sheets in an atmosphere of 25 ° C. and 60% RH, sealed in a moisture-proof bag with the front and back in contact, and then subjected to the same evaluation as above after being stored at 55 ° C. for 3 days. (Photograph for age).
[0109]
The evaluation results are shown in Table 1.
[0110]
[Table 1]

[0111]
    referenceExample 2
  (Production of support)
  Concentration of 0.170 (Konica Densitometer PDA-65) colored blue, 8 W / m on both sides of a 175 μm thick PET film²・ Corona discharge treatment was performed for a minute.
[0112]
(Preparation of photosensitive silver halide emulsion B)
After dissolving 7.5 g of ossein gelatin having an average molecular weight of 100,000 and 10 mg of potassium bromide in 900 ml of water, adjusting the temperature to 35 ° C. and pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate (98/2) An aqueous solution containing potassium bromide and potassium iodide in a molar ratio of iridium chloride and 1 × 10 5 per silver mole^-FourMole was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. Thereafter, 0.3 g of 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 12%, Cubic silver iodobromide grains having a [100] face ratio of 87% were obtained. The emulsion was coagulated and precipitated using a gelatin flocculant, desalted, and 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5 to obtain photosensitive silver halide emulsion B.
[0113]
(Preparation of powdered organic silver salt B)
In 9450 ml of pure water, 324 g of behenic acid, 99 g of arachidic acid and 56 g of stearic acid were dissolved at 80 ° C. Next, 980 ml of a 1.5 M aqueous sodium hydroxide solution was added while stirring at high speed. Next, after adding 9.3 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes, and the silver halide emulsion B (containing 0.9 mol of silver and 1400 g of water) was added over 5 seconds. After stirring for 1 minute, 1470 ml of 1M silver nitrate solution was added over 2 minutes, stirred for another 20 minutes, and water-soluble salts were removed by filtration. Thereafter, washing with deionized water and filtration are repeated until the electric conductivity of the filtrate reaches 2 μS / cm, and centrifugal dehydration is performed, followed by drying with warm air at 37 ° C. until there is no mass loss, and powdered organic silver salt B Got.
[0114]
(Preparation of photosensitive emulsion dispersion)
14.57 g of polyvinyl butyral powder (Monsanto Butvar B-79) was dissolved in 1457 g of methyl ethyl ketone, and 500 g of powdered organic silver salt B was gradually added while stirring with a dissolver type homogenizer and mixed well. Thereafter, dispersion was carried out at a peripheral speed of 13 m and a residence time in the mill of 3 minutes using a media type dispersing machine (gettzmann) filled with 80% of 1 mmZr beads (manufactured by Toray) to prepare a photosensitive emulsion dispersion.
[0115]
<Preparation of infrared sensitizing dye solution>
Sensitizing dye-2 350 mg, 2-chloro-benzoic acid 13.96 g, and 5-methyl-2-mercaptobenzimidazole 2.14 g were dissolved in 73.4 ml of methanol in the dark to prepare an infrared sensitizing dye solution. did.
[0116]
<Preparation of stabilizer solution>
Stabilizer solution was prepared by dissolving 1.0 g of Stabilizer-1 and 0.5 g of potassium acetate in 8.5 g of methanol.
[0117]
<Preparation of developer solution>
Developer-2 17.74g was melt | dissolved in MEK and it finished to 100 ml, and was set as the developer liquid.
[0118]
<Preparation of antifoggant solution>
Antifoggant-5 5.81 g was dissolved in MEK, finished to 100 ml, and used as an antifoggant solution.
[0119]
(Preparation of image forming layer coating solution)
The photosensitive emulsion dispersion (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, 390 μl of antifoggant-4 (10% methanol solution) was added, and the mixture was stirred for 1 hour. Further, 889 μl of calcium bromide (10% methanol solution) was added and stirred for 30 minutes.
[0120]
Next, 1.416 ml of infrared sensitizing dye solution and 667 μl of stabilizer solution were added and stirred for 1 hour, and then the temperature was lowered to 13 ° C. and stirred for another 30 minutes. While maintaining the temperature at 13 ° C., 13.31 g of polyvinyl butyral (Monsanto Butvar B-79) was added and stirred for 30 minutes, and then the following additives were added at intervals of 15 minutes while further stirring was continued.
[0121]

Were sequentially added and stirred to obtain an image forming layer coating solution.
[0122]
[Chemical 8]

[0123]

A liquid having the composition was prepared.
[0124]
Five coating solutions obtained above were prepared, and the image forming layer coating solution was applied immediately after passing through a column packed with the desiccant shown in Table 2 at 15 ° C., dried at 75 ° C. for 5 minutes, and heated. A developing material was prepared. The applied silver amount is 2 g / m.²It applied so that it might become.
[0125]
<Measurement of water content of coating solution>
Measurement was performed by the Karl Fischer method using MKA-210 manufactured by Kyoto Electronics Co., Ltd. as an apparatus using the coating solution prepared above. As the Karl Fischer reagent SS, Mitsubishi Chemical No. E98062, and as a dehydrating solvent CM, Mitsubishi Chemical No. L97988 was used.
[0126]
  In addition, the measurement of the equilibrium moisture content of heat developable material isreferenceSame as Example 1.
  << Exposure and development process >>
  The photosensitive material produced as described above is split in half, and exposure by laser scanning is performed from one emulsion surface side using an exposure machine using a semiconductor laser having a longitudinal multimode wavelength of 800 nm to 820 nm by high frequency superposition as an exposure source. Gave. At this time, an image was formed by setting the angle between the exposure surface of the photosensitive material and the exposure laser beam to 75 degrees (note that the unevenness is less than that when the angle is 90 degrees, and sharpness is unexpectedly good. An image was obtained.)
[0127]
Thereafter, an automatic developing machine having a heat drum was used for heat development at 110 ° C. for 15 seconds so that the protective layer of the photosensitive material was in contact with the drum surface. At that time, exposure and development were performed in a room adjusted to 25 ° C. and 60% RH (room temperature photographic properties). The obtained image was evaluated with a densitometer. The result of the measurement was evaluated by sensitivity (reciprocal of the ratio of the exposure amount giving a density 1.0 higher than that of the unexposed portion) and fog, and indicated as a relative value with the sensitivity of the photosensitive material 1 being 100. The rest was divided into a plurality of sheets under an atmosphere of 25 ° C. and 60% RH, sealed in a moisture-proof bag with the front and back in contact, and then subjected to the same evaluation as above after being stored at 55 ° C. for 3 days. (Photograph for age).
[0128]
The evaluation results are shown in Table 2.
[0129]
[Table 2]

[0130]
    referenceExample 3
  referenceA support was prepared in the same manner as in Example 2 to prepare photosensitive silver halide emulsion B.
[0131]
(Preparation of powdered organic silver salt)
In 4720 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 1.5 M aqueous sodium hydroxide solution was added while stirring at high speed. Next, 6.9 ml of concentrated nitric acid was added and then cooled to 55 ° C. to obtain an organic acid sodium solution. While maintaining this solution at 55 ° C., the silver halide emulsion B (containing 0.038 mol of silver) and 450 ml of pure water were added and stirred for 5 minutes, and then 760.6 ml of 1M silver nitrate solution was added over 2 minutes. The mixture was further stirred for 20 minutes, and water-soluble salts were removed by filtration. Thereafter, washing with deionized water and filtration were repeated until the electric conductivity of the filtrate reached 2 μS / cm, centrifugal dehydration was performed, and hot air drying was performed at 37 ° C. At this time, by changing the drying time, the water content of the powdered organic silver salt was changed and used for the following evaluation. The water content was calculated by measuring the mass when the obtained organic silver salt powder was dried at high temperature.
[0132]
[Table 3]

[0133]
    Photosensitive emulsion dispersion and infrared sensitizing dye liquid (sensitizing dye-1 was used in place of sensitizing dye-2)referencePrepared as in Example 2.
[0134]
(Preparation of image forming layer coating solution)
The photosensitive emulsion dispersion (500 g) and 100 g of MEK were kept at 21 ° C. with stirring, 0.02 g of bis (dimethylacetamide) dibromobromate was added and stirred for 1 hour.
[0135]
Next, 1.5 ml of an infrared sensitizing dye solution was added and stirred for 1 hour, and then the temperature was lowered to 13 ° C. and stirred for another 30 minutes. While keeping the temperature at 13 ° C., 48 g of polyvinyl butyral (supra) was added and dissolved sufficiently,
Phthalazine 1.5g
Tetrachlorophthalic acid 0.5g
4-methylphthalic acid 0.5g
2- (Tribromomethyl-sulfonyl) -pyridine 1.9 g
Developer-2 15g
Aliphatic isocyanate (supra) 1.10 g
Was added.
[0136]
This preparation was performed by changing the conditions such that the humidity was 80% RH, 50% RH, 35% RH, and the time of nitrogen substitution was 30%, 50%, and 100% of the time required for all steps. It shows in Table 4 about the preparation conditions and water content of each coating liquid. The water content was measured in the same manner as in Example 2.
[0137]
[Table 4]

[0138]
The following layers were sequentially formed on a support and dried at 75 ° C. for 5 minutes to prepare a sample.
[0139]
(Back side application)
Polyvinyl butyral 150ml
Dye-B 70mg
Dye-C 70mg
The coating solution having the composition was applied so as to have a wet thickness of 80 μm.
[0140]
(Image-forming layer side coating)
The image forming layer coating solution has a coating silver amount of 2.0 g / m.², 8.5 g / m of polyvinyl butyral as a binder²It applied so that it might become.
[0141]
Then
175 ml of acetone
Methanol 15ml
Cellulose acetate butyrate 8.0g
Phthalazine 1.0g
4-methylphthalic acid 0.72g
Tetrachlorophthalic acid 0.22g
Tetrachlorophthalic anhydride 0.5g
1% by weight based on monodispersed silica binder with an average particle size of 4 μm
A surface protective layer coating solution having the composition consisting of the following was applied at a wet thickness of 100 μm.
[0142]
  << Exposure and development process >>
  From the emulsion surface side of the photosensitive material prepared as described above,referenceIn the same manner as in Example 2, exposure was performed by laser scanning, and an image was formed with the exposure surface of the photosensitive material and the angle of the exposure laser beam being 75 degrees (note that an image with little unevenness and unexpectedly good sharpness, etc. was formed. I gotreferenceSimilar to Example 2. ).
[0143]
  afterwards,referenceThe heat development processing was carried out in the same manner as in Example 2. However, exposure and development were performed in a room conditioned at 25 ° C. and 50% RH, and the obtained image was evaluated with a densitometer. Evaluation was made based on sensitivity and fog. The sensitivity is shown as a relative value where the sensitivity of N = 1 is 1. Furthermore, each image forming layer coating solution was prepared three times (N = 3), and sensitometry was evaluated to evaluate production stability.
[0144]
The results are shown in Table 5.
[0145]
[Table 5]

[0146]
(Embodiments according to inventions (4) to (6))
Example 4
<Preparation of photographic support>
A polymer resin was obtained as follows.
[0147]
(PET resin)
0.05 parts by mass of magnesium acetate hydrate was added as a transesterification catalyst to 100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol, and transesterification was performed according to a conventional method. To the obtained product, 0.05 part by mass of antimony trioxide and 0.03 part by mass of trimethyl phosphate were added. Subsequently, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 280 ° C. and 0.5 mmHg to obtain a polyethylene terephthalate (PET) resin having an intrinsic viscosity of 0.50.
[0148]
(PEN resin)
To 100 parts by mass of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by mass of ethylene glycol, 0.1 part by mass of magnesium acetate hydrate was added as a transesterification catalyst, and transesterification was performed according to a conventional method. To the obtained product, 0.05 part by mass of antimony trioxide and 0.03 part by mass of trimethyl phosphate were added. Subsequently, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 290 ° C. and 0.5 mmHg to obtain a polyethylene-2,6-naphthalate (PEN) resin having an intrinsic viscosity of 0.58.
[0149]
(Copolymerized PET resin (M-PET resin))
100 parts by mass of dimethyl terephthalate, 56 parts by mass of ethylene glycol, 28 parts by mass of an ethylene glycol solution (concentration 35%) of 5-sodium sulfo-di (β-hydroxyethyl) isophthalic acid was added, and magnesium acetate water as a transesterification catalyst 0.1 part by mass of a Japanese product was added, and transesterification was performed according to a conventional method. To the obtained product, 0.04 part by mass of antimony trioxide and 0.1 part by mass of trimethyl phosphate were added. Next, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 285 ° C. and 0.5 mmHg to obtain a copolymerized polyester (M-PET) resin mainly composed of polyethylene terephthalate having an intrinsic viscosity of 0.40.
[0150]
Using each polymer obtained as described above, a biaxially stretched polymer film was produced as follows.
[0151]
(PET support film and M-PET support film)
Pelletized PET resin or M-PET resin is vacuum dried at 150 ° C. for 8 hours, melted and extruded in layers from a T die at 285 ° C., and brought into close contact with electrostatic application on a cooling drum at 30 ° C. Solidified to obtain an unstretched film. This unstretched sheet was stretched 3.3 times in the longitudinal direction at 80 ° C. using a roll type longitudinal stretching machine. The obtained uniaxially stretched film was stretched by 50% of the total transverse stretching ratio in the first stretching zone at 90 ° C. using a tenter-type transverse stretching machine, and further increased to 3.3 times in the second stretching zone at 100 ° C. It extended | stretched so that it might become. Subsequently, pre-heat treatment was performed at 70 ° C. for 2 seconds, and heat setting was further performed at the first fixing zone 150 ° C. for 5 seconds, and heat setting was performed at the second fixing zone 220 ° C. for 15 seconds. Subsequently, the film was cooled to room temperature over 60 seconds with 5% relaxation treatment in the transverse direction, the film was released from the clip, wound up, and a biaxially stretched film having a thickness of 180 μm was obtained.
[0152]
(PEN support film)
Instead of the PET resin of Comparative Example 1, a PEN resin was used, a melt extrusion temperature of 300 ° C., a cooling drum temperature of 50 ° C., a longitudinal stretching temperature of 135 ° C., a first transverse stretching zone temperature of 145 ° C., and a second transverse stretching zone temperature of 155 ° C. A biaxially stretched film having a thickness of 180 μm was obtained in the same manner as in Comparative Example 1, except that the pre-heat treatment temperature was 100 ° C., the first fixing zone temperature was 200 ° C., and the second fixing zone temperature was 230 ° C.
[0153]
<Preparation of undercoated photographic support>
8 w / m on the side on which the heat-developable image forming layer of the 180 μm-thick photographic support prepared above is coated.²Corona discharge treatment was applied for a minute, and the following undercoat coating solution a′-1 was applied to a dry film thickness of 0.8 μm and dried to form an undercoat layer A′-1. Some samples were further heat treated at 100 ° C. for 10 minutes and covered with a moisture-proof sheet immediately after winding.
[0154]
<< Undercoat coating liquid a'-1 >>
250g polyester latex liquid b-1 (15% solid content)
(C′-1) 0.6 g
Finish to 1 liter with water
[0155]
[Chemical 9]

[0156]
<Coating of backing layer>
The backing layer coating solution B′-1 shown below was applied and dried on the side opposite to the side of the undercoated photographic support, so that the following amount was applied. The drying was performed at 100 ° C. for 5 minutes.
[0157]

(Preparation of silver halide 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 35 ° 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 350 ml of an aqueous solution containing 51 g of potassium and 1.5 g of potassium iodide and [Ir (NO) Cl_Five] 1 x 10 salt per mole of silver^-6Mole and rhodium chloride salt at 1 × 10 5 per mole of silver^-FourMole was added by the controlled double jet method while maintaining pAg 7.7. Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added and the pH was adjusted to 5 with NaOH to change the projected diameter area with an average particle size of 0.06 μm and a monodispersity of 10%. Cubic silver iodobromide grains having a coefficient of 8% and a [100] face ratio of 87% were obtained. This emulsion was coagulated and precipitated using a gelatin flocculant, desalted and then added with 0.1 g of phenoxyethanol to adjust the pH to 5.9 and pAg 7.5 to obtain a silver halide emulsion A ′. Furthermore, chemical sensitization was performed with chloroauric acid and inorganic sulfur.
[0158]
(Preparation of Na behenate solution)
To 945 ml of pure water were added 32.4 g of behenic acid, 9.9 g of arachidic acid, and 5.6 g of stearic acid, and the mixture was stirred at 90 ° C. Next, 98 ml of an aqueous 1.5N sodium hydroxide solution was added while stirring at high speed. Next, 0.93 ml of concentrated nitric acid was added, and then cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium behenate solution.
[0159]
(Preparation of preform emulsion A ′ from sodium behenate and silver halide A ′)
15.1 g of the silver halide emulsion A ′ was added to the above sodium behenate solution and adjusted to pH 8.1 with a sodium hydroxide solution. Then, 147 ml of 1M silver nitrate solution was added over 7 minutes, and the mixture was further stirred for 20 minutes. Water-soluble salts were removed by external filtration. The resulting silver behenate was a grain having an average grain size of 0.8 μm and a monodispersity of 8%. After forming the floc of the dispersion, the water was removed, and after further washing with water 6 times and removing the water, drying was performed. This is designated as Preform Emulsion A ′.
[0160]
(Preparation of photosensitive emulsion A ')
544 g of a methyl ethyl ketone solution (17% by mass) of polyvinyl butyral (average molecular weight 3000) and 107 g of toluene were gradually added to and mixed with the preformed emulsion A ′, and then dispersed at 4000 psi. This is called photosensitive emulsion A '.
[0161]

The amount of silver applied is 2.1 g / m.²It applied so that it might become.
[0162]

A liquid having the composition was applied on the image forming layer.
[0163]
The backing layer, the image forming layer, and the surface protective layer are applied by adjusting the relative humidity shown in Table 6 for 3 hours, then the backing layer is applied, and then the image forming layer and the surface protective layer are simultaneously applied in a multilayer. And dried at a drying temperature of 80 ° C. for 5 minutes. However, in the case where heat treatment was performed in the previous step and the moisture-proof sheet was covered, application was performed immediately after removing the sheet.
[0164]
<< Exposure and development process >>
The photothermographic material produced above was subjected to scanning exposure of 5 cm in length and 5 cm in width (beam diameter 8 μm, scanning pitch 5 μm) with an imager having a 810 nm, 100 mW semiconductor laser to form a latent image. Thereafter, using an automatic developing machine having a heat drum, heat development was performed at 110 ° C. for 15 seconds so that the heat drum was in contact with the heat-developable image forming layer side. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH.
[0165]
<Evaluation of image forming material>
(Thermal image dimensional stability)
After heat development, measure the length of each side of the square of the formed image, the difference between the length and the length after exposure (5 cm) as the thermal image dimensional stability,
A: Less than 0.01
B: 0.01 or more and less than 0.02
C: 0.02 or more and less than 0.04
D: 0.04 or more and less than 0.06
E: 0.06 or more
It was evaluated with.
[0166]
(With membrane)
Using a razor, the surface of the surface on which the image forming layer of the sample that had been heat-developed by being pressed against a 120 ° C. heat development drum for 25 seconds was scratched with 6 razors at intervals of 4 mm to obtain 25 mm. I made a cell. However, the scratch was made at a depth reaching the surface of the support. A Mylar tape having a width of 25 mm was stuck on this and sufficiently bonded. Five minutes after the pressure bonding, the Mylar tape was peeled off from the sample by abruptly pulling at a peeling angle of 180 degrees. At this time, the number of squares from which the image forming layer peeled off from the sample was counted,
A: No peeling
[0167]
B: Peeling less than 1 mm
C: Peeling less than 5 mm
D: More than 5 mm peeling
Classified by. A and B are levels at which there is no practical problem.
[0168]
(Evaluation of raw preservation)
The heat-developable material prepared above is put in a moisture-proof bag, conditioned at 23 ° C. and 55% RH for 4 hours, and then divided into two. One is subjected to the exposure and heat-development treatment immediately after humidity adjustment, and the other is After heat-preserving in a moisture-proof bag at 3 ° C. for 3 days, exposure and heat development were similarly performed. The evaluation (fogging) of the obtained image was performed with a densitometer, and the difference between the heat-treated image and the untreated image was used as a measure of the raw storage stability. The fog density measured at this time is a value obtained by subtracting the base density.
[0169]
As shown in Table 6, the heat-developable material described in Table 6 was prepared by changing the relative humidity in the presence / absence of heat treatment of the underdrawn support and in the application process of the image forming layer and the backing layer and the humidity control of the support. Then, the thermal dimensional stability, film attachment, and raw storage stability of the heat developing material were evaluated.
[0170]
The water content of the support was measured before thermal development immediately before evaluation of thermal dimensional stability, film attachment, and raw storage stability. The slow cooling in Table 6 is a cooling operation in which the support coated with the undercoat layer is heat treated at 100 ° C. for 10 minutes, cooled at a rate of 70 ° C. in 5 minutes, and then allowed to cool to room temperature. Point to. Annealing is a heat treatment in which a support is allowed to stand at room temperature after being heat-treated at 100 ° C. for 10 minutes and then allowed to stand at 60 ° C. for 40 hours. Table 6 shows the evaluation results.
[0171]
[Table 6]

[0172]
As is apparent from Table 6, when the water content of the heat-developable material support is 0.5% or less, it is found that the film attachment is good and the heat-resistant dimensional stability and raw storage stability are excellent.
[0173]
Example 5
Next, the methanol ratio in the image forming layer was changed as shown in Table 7 by changing the methanol used for dissolving the compound added to the image forming layer to methanol / MEK mixed at an arbitrary ratio. For Samples 5-3 and 5-4, the coating solution was brought into contact with a desiccant (silica gel) for 1 hour before coating the image forming layer. The other conditions were prepared and evaluated in the same manner as Sample 4-1 of Example 4.
[0174]
The results are shown in Table 7. In addition, about raw preservation | save property, the storage temperature for 3 days was 65 degreeC.
[0175]
[Table 7]

[0176]
As is apparent from Table 7, when the water content of the coating solution for the image forming layer of the heat developing material is 2.0% or less, the film is good and the heat resistant dimensional stability and raw storage stability are excellent.
[0177]
Example 6
Next, after the image forming layer was applied, re-drying was performed under the conditions described in Table 8, and the ratio of methyl ethyl ketone, which is the solvent of the image forming layer, and toluene was changed. Similarly, a heat-developable material was prepared and evaluated.
[0178]
The results are shown in Table 8. Note that the storage period was 6 days for raw storage.
[0179]
[Table 8]

[0180]
As is apparent from Table 8, when the heat developing material was left at 23 ° C. and 55% RH for 3 hours when the water content was 0.5% or less and the solvent residual ratio was 2.0% or less, the film was attached. Good, heat-resistant dimensional stability and raw storage stability.
[0181]
【The invention's effect】
According to the present invention, it is possible to provide a heat developing material having high sensitivity, low fog at the time of production and raw storage, no film peeling at the time of heat development, and excellent heat resistance dimensional stability.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a surface treatment apparatus that performs discharge treatment.
FIG. 2 is a schematic configuration diagram of another surface treatment apparatus.
[Explanation of symbols]
1 Support
2, 3 electrodes
4,5 dielectric
6,7 Supply port
8 Nip roller
9 Power supply
10 Surface treatment equipment

Claims (4)

A heat-developable material having an image forming layer on a support and having an equilibrium water content of 3% by mass or less at 25 ° C. and 60% RH, wherein the image forming layer is contacted with a desiccant to remove moisture. And a layer formed by applying and drying a coating solution using at least one selected from the following water-miscible solvents, and the support is heat-treated or discharged when applying the coating solution, A heat-developable material, wherein the support has a water content of 0.33% by mass or less when applied.
Water miscible solvents: acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, butanol, tetrahydrofuran, dioxane, dioxolane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone   2. The heat developing material according to claim 1, wherein the image forming layer contains an organic silver salt and photosensitive silver halide grains.   2. The heat developing material according to claim 1, wherein the water miscible solvent is methyl ethyl ketone.   The method for producing a heat-developable material according to claim 1, wherein the residual solvent ratio of the heat-developable material after drying is 2.0% by mass or less.

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