JP3626309B2 - Photothermographic material - Google Patents

Description

【００３６】
表面保護層には必要に応じて有機銀塩、該銀塩の還元剤、色調剤、カブリ防止剤、マット剤、染料、スベリ剤、界面活性剤、などを添加してもよい。
【００３７】
表面保護層に用いられるマット剤としてはポリスチレン、ポリメチルメタクリレート、シリカなどの微粒子が好ましい。粒子の形状には特に制限はないが、球形の微粒子は好ましい。マット剤の粒径は０．２〜２０μｍ 、より好ましくは０．５〜１０μｍ 程度が好ましい。マット剤の添加量は熱現像感光材料の層構成、厚みや使用目的によって一概にいえないが、１０から２００ｍｇ／ｍ^２、より好ましくは２０から１００ｍｇ／ｍ^２程度が好ましい。
【００３８】
表面保護層に用いられるスベリ剤としてはシリコン化合物、パラフィンなど当業界で公知な化合物を用いてよい。
【００３９】
本発明における熱現像感光材料は、支持体の感光層が塗設されている面の反対側の面にバック層を設けてもよい。
【００４０】
本発明のバック層のバインダーには特に制限はなく、表面保護層のバインダーのところで述べたポリマーが使用できる。さらにバインダーとして感光層のところで述べたポリマーラテックス、特に２５℃６０％ＲＨにおける平衡含水率が２ｗｔ％ 以下のポリマーラテックスは特に好ましい。
【００４１】
本発明のバック層は前述の水系塗布液を塗布乾燥して形成することが好ましい。
【００４２】
本発明においてバック層は、所望の波長範囲での最大吸収が０．３ 以上２以下であることが好ましく、さらに好ましくは０．５ 以上２以下の吸収であり、かつ処理後の可視領域においての吸収が０．００１ 以上０．５ 未満であることが好ましく、さらに好ましくは０．００１ 以上０．３ 未満の光学濃度を有する層であることが好ましい。
【００４３】
本発明のバック層には、必要に応じてシリカ、ポリメチルメタクリレートなどのマット剤を添加してもよい。
【００４４】
本発明のバック層にはさらに必要に応じて界面活性剤、架橋剤、スベリ剤などを添加してもよい。
【００４５】
また米国特許第４，４６０，６８１号および同第４，３７４，９２１号に示されるような裏面抵抗性加熱層（ｂａｃｋｓｉｄｅ ｒｅｓｉｓｔｉｖｅ ｈｅａｔｉｎｇ ｌａｙｅｒ）を設けることもできる。
【００４６】
本発明のバック層の厚みは０．１〜２０μｍ 、より好ましくは０．５〜１０μｍ が好ましい。
【００４７】
本発明の熱現像感光材料はバック層の上に保護層（バック面保護層）を設けてもよい。バック面保護層のバインダーには特に制限はなく、バック層のところで述べたポリマーが使用できるが、このうちで親水性ポリマーが特に好ましい。本発明のバック保護層も前述の水系塗布液を塗布乾燥して形成することが好ましい。
【００４８】
本発明のバック保護層は表面保護層と同様に架橋することが好ましい。架橋剤としては前述のものが使用できる。発明のバック面保護層にも必要に応じて前述のマット剤、染料、スベリ剤、界面活性剤などを添加してもよい。本発明のバック面保護層の厚みは０．１〜１０μｍ 、より好ましくは０．５〜５μｍ の範囲が好ましい。
【００４９】
本発明においてバック面のマット度としてはベック平滑度が２５０秒以下１０秒以上が好ましく、さらに１８０秒以下５０秒以上が好ましい。
【００５０】
本発明における感光性ハロゲン化銀の形成方法は当業界ではよく知られており例えば、リサーチディスクロージャー１９７８年６月の第１７０２９ 号、および米国特許第３，７００，４５８ 号に記載されている方法を用いることができる。本発明で用いることのできる具体的な方法としては、調製された有機銀塩中にハロゲン含有化合物を添加することにより有機銀塩の銀の一部を感光性ハロゲン化銀に変換する方法、ゼラチンあるいは他のポリマー溶液の中に銀供給化合物及びハロゲン供給化合物を添加することにより感光性ハロゲン化銀粒子を調製し有機銀塩と混合する方法を用いることができる。本発明において好ましくは後者の方法を用いることができる。感光性ハロゲン化銀の粒子サイズは、画像形成後の白濁を低く抑える目的のために小さいことが好ましく具体的には０．２０μｍ以下、より好ましくは０．０１μｍ 以上０．１５μｍ 以下、更に好ましくは０．０２μｍ以上０．１２μｍ以下がよい。ここでいう粒子サイズとは、ハロゲン化銀粒子が立方体あるいは八面体のいわゆる正常晶である場合にはハロゲン化銀粒子の稜の長さをいう。また、ハロゲン化銀粒子が平板状粒子である場合には主表面の投影面積と同面積の円像に換算したときの直径をいう。その他正常晶でない場合、たとえば球状粒子、棒状粒子等の場合には、ハロゲン化銀粒子の体積と同等な球を考えたときの直径をいう。
【００５１】
ハロゲン化銀粒子の形状としては立方体、八面体、平板状粒子、球状粒子、棒状粒子、ジャガイモ状粒子等を挙げることができるが、本発明においては特に立方体状粒子、平板状粒子が好ましい。平板状ハロゲン化銀粒子を用いる場合の平均アスペクト比は好ましくは１００：１ 〜２：１ 、より好ましくは５０：１〜３：１ がよい。更に、ハロゲン化銀粒子のコーナーが丸まった粒子も好ましく用いることができる。感光性ハロケン化銀粒子の外表面の面指数（ミラー指数）については特に制限はないが、分光増感色素が吸着した場合の分光増感効率が高い｛１００｝ 面の占める割合が高いことが好ましい。その割合としては５０％以上が好ましく、６５％ 以上がより好ましく、８０％ 以上が更に好ましい。ミラー指数｛１００｝ 面の比率は増感色素の吸着における｛１１１｝ 面と｛１００｝ 面との吸着依存性を利用したＴ．Ｔａｎｉ；Ｊ．Ｉｍａｇｉｎｇ Ｓｃｉ．，２９、１６５（１９８５ 年） に記載の方法により求めることができる。感光性ハロゲン化銀のハロゲン組成としては特に制限はなく、塩化銀、塩臭化銀、臭化銀、ヨウ臭化銀、ヨウ塩臭化銀、ヨウ化銀のいずれであっても良いが、本発明においては臭化銀、あるいはヨウ臭化銀を好ましく用いることができる。特に好ましくはヨウ臭化銀であり、ヨウ化銀含有率は０．１ モル％以上４０モル％以下が好ましく、０．１ モル％以上２０モル％以下がより好ましい。粒子内におけるハロゲン組成の分布は均一であってもよく、ハロゲン組成がステップ状に変化したものでもよく、或いは連続的に変化したものでもよいが、好ましい例として粒子内部のヨウ化銀含有率の高いヨウ臭化銀粒子を使用することができる。また、好ましくはコア／シェル構造を有するハロゲン化銀粒子を用いることができる。構造としては好ましくは２〜５重構造、より好ましくは２〜４重構造のコア／シェル粒子を用いることができる。
【００５２】
本発明の感光性ハロゲン化銀粒子は、ロジウム、レニウム、ルテニウム、オスニウム、イリジウム、コバルト、水銀または鉄から選ばれる金属の錯体を少なくとも一種含有することが好ましい。これら金属錯体は１ 種類でもよいし、同種金属及び異種金属の錯体を二種以上併用してもよい。好ましい含有率は銀１モルに対し１ｎモルから１０ｍ モルの範囲が好ましく、１０ｎ モルから１００μモルの範囲がより好ましい。具体的な金属錯体の構造としては特開平７−２２５４４９号等に記載された構造の金属錯体を用いることができる。コバルト、鉄の化合物については六シアノ金属錯体を好ましく用いることができる。具体例としては、フェリシアン酸イオン、フェロシアン酸イオン、ヘキサシアノコバルト酸イオンなどが挙げられるが、これらに限定されるものではない。ハロゲン化銀中の金属錯体の含有相は均一でも、コア部に高濃度に含有させてもよく、あるいはシェル部に高濃度に含有させてもよく特に制限はない。
【００５３】
感光性ハロゲン化銀粒子はヌードル法、フロキュレーション法等、当業界で知られている方法の水洗により脱塩することができるが本発明においては脱塩してもしなくてもよい。
【００５４】
本発明における感光性ハロゲン化銀粒子は化学増感されていることが好ましい。好ましい化学増感法としては当業界でよく知られているように硫黄増感法、セレン増感法、テルル増感法を用いることができる。また金化合物や白金、パラジウム、イリジウム化合物等の貴金属増感法や還元増感法を用いることができる。硫黄増感法、セレン増感法、テルル増感法に好ましく用いられる化合物としては公知の化合物を用いることができるが、特開平７−１２８７６８号等に記載の化合物を使用することができる。テルル増感剤としては例えばジアシルテルリド類、ビス（ オキシカルボニル） テルリド類、ビス（ カルバモイル） テルリド類、ジアシルテルリド類、ビス（ オキシカルボニル） ジテルリド類、ビス（ カルバモイル） ジテルリド類、Ｐ＝Ｔｅ結合を有する化合物、テルロカルボン酸塩類、Ｔｅ−オルガニルテルロカルボン酸エステル類、ジ（ ポリ） テルリド類、テルリド類、テルロール類、テルロアセタール類、テルロスルホナート類、Ｐ−Ｔｅ結合を有する化合物、含Ｔｅヘテロ環類、テルロカルボニル化合物、無機テルル化合物、コロイド状テルルなどを用いることができる。貴金属増感法に好ましく用いられる化合物としては例えば塩化金酸、カリウムクロロオーレート、カリウムオーリチオシアネート、硫化金、金セレナイド、あるいは米国特許２，４４８，０６０ 号、英国特許６１８，０６１ 号など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。還元増感法の具体的な化合物としてはアスコルビン酸、二酸化チオ尿素の他に例えば、塩化第一スズ、アミノイミノメタンスルフィン酸、ヒドラジン誘導体、ボラン化合物、シラン化合物、ポリアミン化合物等を用いることができる。また、乳剤のｐＨを７以上またはｐＡｇ を８．３ 以下に保持して熟成することにより還元増感することができる。また、粒子形成中に銀イオンのシングルアディション部分を導入することにより還元増感することができる。
【００５５】
本発明の感光性ハロゲン化銀の使用量としては有機銀塩１ モルに対して感光性ハロゲン化銀０．０１モル０．５ モル以下が好ましく、０．０２モル以上０．３ モル以下がより好ましく、０．０３モル以上０．２５モル以下が特に好ましい。別々に調製した感光性ハロゲン化銀と有機銀塩の混合方法及び混合条件については、それぞれ調製終了したハロゲン化銀粒子と有機銀塩を高速攪拌機やボールミル、サンドミル、コロイドミル、振動ミル、ホモジナイザー等で混合する方法や、あるいは有機銀塩の調製中のいずれかのタイミングで調製終了した感光性ハロゲン化銀を混合して有機銀塩を調製する方法等があるが、本発明の効果が十分に現れる限りにおいては特に制限はない。
【００５６】
本発明のハロゲン化銀調製法としては、有機銀塩の一部の銀を有機または無機のハロゲン化物でハロゲン化するいわゆるハライデーション法も好ましく用いられる。ここで用いる有機ハロゲン化物としては有機銀塩と反応しハロゲン化銀を生成する化合物で有ればいかなる物でもよいが、Ｎ−ハロゲノイミド（Ｎ− ブロモスクシンイミドなど） 、ハロゲン化４級窒素化合物（ 臭化テトラブチルアンモニウムなど） 、ハロゲン化４ 級窒素塩とハロゲン分子の会合体（ 過臭化臭化ピリジニウム） などが挙げられる。無機ハロゲン化合物としては有機銀塩と反応しハロゲン化銀を生成する化合物で有ればいかなる物でもよいが、ハロゲン化アルカリ金属またはアンモニウム（塩化ナトリウム、臭化リチウム、沃化カリウム、臭化アンモニウムなど）、ハロゲン化アルカリ土類金属（臭化カルシウム、塩化マグネシウムなど）、ハロゲン化遷移金属（塩化第２鉄、臭化第２銅など）、ハロゲン配位子を有する金属錯体（臭化イリジウム酸ナトリウム、塩化ロジウム酸アンモニウムなど）、ハロゲン分子（臭素、塩素、沃素）などがある。また、所望の有機無機ハロゲン化物を併用しても良い。
【００５７】
本発明でハライデーションする際のハロゲン化物の添加量としては有機銀塩１モル当たりハロゲン原子として１ｍモル〜５００ｍモルが好ましく、１０ｍ モル〜２５０ｍモルがさらに好ましい。
【００５８】
本発明に用いることのできる有機銀塩は、光に対して比較的安定であるが、露光された光触媒（感光性ハロゲン化銀の潜像など）及び還元剤の存在下で、８０℃或いはそれ以上に加熱された場合に銀画像を形成する銀塩である。有機銀塩は銀イオンを還元できる源を含む任意の有機物質であってよい。有機酸の銀塩、特に（ 炭素数が１０〜３０、好ましくは１５〜２８の） 長鎖脂肪カルボン酸の銀塩が好ましい。配位子が４．０ 〜１０．０の範囲の錯安定定数を有する有機または無機銀塩の錯体も好ましい。銀供給物質は、好ましくは画像形成層の約５〜７０重量％を構成することができる。好ましい有機銀塩はカルボキシル基を有する有機化合物の銀塩を含む。これらの例は、脂肪族カルボン酸の銀塩および芳香族カルボン酸の銀塩を含むがこれらに限定されることはない。脂肪族カルボン酸の銀塩の好ましい例としては、ベヘン酸銀、ステアリン酸銀、オレイン酸銀、ラウリン酸銀、カプロン酸銀、ミリスチン酸銀、パルミチン酸銀、マレイン酸銀、フマル酸銀、酒石酸銀、リノール酸銀、酪酸銀及び樟脳酸銀、これらの混合物などを含む。
【００５９】
メルカプト基またはチオン基を含む化合物の銀塩及びこれらの誘導体を使用することもできる。これらの化合物の好ましい例としては、３−メルカプト−４− フェニル−１，２，４− トリアゾールの銀塩、２−メルカプトベンズイミダゾールの銀塩、２−メルカプト−５− アミノチアジアゾールの銀塩、２−（エチルグリコールアミド）ベンゾチアゾールの銀塩、Ｓ−アルキルチオグリコール酸（ ここでアルキル基の炭素数は１２〜２２である） の銀塩などのチオグリコール酸の銀塩、ジチオ酢酸の銀塩などのジチオカルボン酸の銀塩、チオアミドの銀塩、５−カルボキシル−１− メチル−２− フェニル−４− チオピリジンの銀塩、メルカプトトリアジンの銀塩、２−メルカプトベンズオキサゾールの銀塩、米国特許第４，１２３，２７４ 号に記載の銀塩、例えば３−アミノ−５− ベンジルチオ−１，２，４− チアゾールの銀塩などの１，２，４−メルカプトチアゾール誘導体の銀塩、米国特許第３，３０１，６７８ 号に記載の３−（３− カルボキシエチル）−４−メチル−４− チアゾリン−２− チオンの銀塩などのチオン化合物の銀塩を含む。さらに、イミノ基を含む化合物も使用することができる。これらの化合物の好ましい例としては、ベンゾトリアゾールの銀塩及びそれらの誘導体、例えばメチルベンゾトリアゾール銀などのベンゾトリアゾールの銀塩、５−クロロベンゾトリアゾール銀などのハロゲン置換ベンゾトリアゾールの銀塩、米国特許第４，２２０，７０９ 号に記載のような１，２，４−トリアゾールまたは１−Ｈ−テトラゾールの銀塩、イミダゾール及びイミダゾール誘導体の銀塩などを含む。例えば、米国特許第４，７６１，３６１ 号及び同第４，７７５，６１３ 号に記載のような種々の銀アセチリド化合物をも使用することもできる。
【００６０】
本発明に用いることができる有機銀塩の形状としては特に制限はないが、短軸と長軸を有する針状結晶が好ましい。本発明においては短軸０．０１μｍ 以上０．２ ０ μｍ 以下、長軸０．１０μｍ 以上５．０ μｍ 以下が好ましく、短軸０．０１μｍ 以上０．１５μｍ 以下、長軸０．１０μｍ 以上４．０ μｍ 以下がより好ましい。有機銀塩の粒子サイズ分布は単分散であることが好ましい。単分散とは短軸、長軸それぞれの長さの標準偏差を短軸、長軸それぞれで割った値の１００ 分率が好ましくは１００％以下、より好ましくは８０％以下、更に好ましくは５０％以下である。有機銀塩の形状の測定方法としては有機銀塩分散物の透過型電子顕微鏡像より求めることができる。単分散性を測定する別の方法として、有機銀塩の体積荷重平均直径の標準偏差を求める方法があり、体積荷重平均直径で割った値の１００ 分率（ 変動係数） が好ましくは１００％以下、より好ましくは８０％以下、更に好ましくは５０％以下である。測定方法としては例えば液中に分散した有機銀塩にレーザー光を照射し、その散乱光のゆらぎの時間変化にたいする自己相関関数を求めることにより得られた粒子サイズ（ 体積荷重平均直径） から求めることができる。
【００６１】
本発明に用いることのできる有機銀塩は、好ましくは脱塩をすることができる。脱塩を行う方法としては特に制限はなく公知の方法を用いることができるが、円心濾過、吸引濾過、限外濾過、凝集法によるフロック形成水洗等の公知の濾過方法を好ましく用いることができる。
【００６２】
本発明に用いることのできる有機銀塩は粒子サイズの小さい、凝集のない微粒子を得る目的で、分散剤を使用した固体微粒子分散物とする方法が用いられる。有機銀塩を固体微粒子分散化する方法は、分散助剤の存在下で公知の微細化手段（例えば、ボールミル、振動ボールミル、遊星ボールミル、サンドミル、コロイドミル、ジェットミル、ローラーミル）を用い、機械的に分散することができる。
【００６３】
有機銀塩を分散剤を使用して固体微粒子化する際には、例えば、ポリアクリル酸、アクリル酸の共重合体、マレイン酸共重合体、マレイン酸モノエステル共重合体、アクリロイルメチルプロパンスルホン酸共重合体、などの合成アニオンポリマー、カルボキシメチルデンプン、カルボキシメチルセルロースなどの半合成アニオンポリマー、アルギン酸、ペクチン酸などのアニオン性ポリマー、特開昭５２−９２７１６号、ＷＯ８８／０４７９４ 号などに記載のアニオン性界面活性剤、特願平７−３５０７５３号に記載の化合物、あるいは公知のアニオン性、ノニオン性、カチオン性界面活性剤や、その他ポリビニルアルコール、ポリビニルピロリドン、カルボキシメチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロース等の公知のポリマー、或いはゼラチン等の自然界に存在する高分子化合物を適宜選択して用いることができる。
【００６４】
分散助剤は、分散前に有機銀塩の粉末またはウェットケーキ状態の有機銀塩と混合し、スラリーとして分散機に送り込むのは一般的な方法であるが、予め有機銀塩と混ぜ合わせた状態で熱処理や溶媒による処理を施して有機銀塩粉末またはウェットケーキとしても良い。分散前後または分散中に適当なｐＨ調整剤によりｐＨコントロールしても良い。
【００６５】
機械的に分散する以外にも、ｐＨコントロールすることで溶媒中に粗分散し、その後、分散助剤の存在下でｐＨを変化させて微粒子化させても良い。このとき、粗分散に用いる溶媒として有機溶媒を使用しても良く、通常有機溶媒は微粒子化終了後除去される。
【００６６】
調製された分散物は、保存時の微粒子の沈降を抑える目的で攪拌しながら保存したり、親水性コロイドにより粘性の高い状態（例えば、ゼラチンを使用しゼリー状にした状態）で保存したりすることもできる。また、保存時の雑菌などの繁殖を防止する目的で防腐剤を添加することもできる。
【００６７】
本発明の有機銀塩は所望の量で使用できるが、０．１ 〜５ｇ／ｍ^２が好ましく、さらに好ましくは１〜３ｇ／ｍ^２である。
【００６８】
有機銀塩のための還元剤は、銀イオンを金属銀に還元するヒンダードフェノール還元剤が用いられる。還元剤は、画像形成層を有する面の銀１モルに対して５〜50% モル含まれることが好ましく、10〜40モル% で含まれることがさらに好ましい。還元剤の添加層は画像形成層を有する面のいかなる層でも良い。画像形成層以外の層に添加する場合は銀１モルに対して10〜50% モルと多めに使用することが好ましい。また、還元剤は現像時のみ有効に機能を持つように誘導化されたいわゆるプレカーサーであってもよい。
【００６９】
ヒンダードフェノール還元剤としては、ビスフェノール、 例えば、ビス(2- ヒドロキシ-3-t- ブチル- 5-メチルフェニル) メタン、2,2-ビス(4- ヒドロキシ-3- メチルフェニル)プロパン、4,4-エチリデン- ビス(2-t- ブチル-6- メチルフェノール) 、1,1,-ビス(2- ヒドロキシ-3,5- ジメチルフェニル)-3,5,5-トリメチルヘキサンおよび2,2-ビス( 3,5-ジメチル-4- ヒドロキシフェニル) プロパンなどが挙げられる。
【００７０】
本発明の還元剤は、溶液、粉末、固体微粒子分散物などいかなる方法で添加してもよい。固体微粒子分散は公知の微細化手段（ 例えば、ボールミル、振動ボールミル、サンドミル、コロイドミル、ジェットミル、ローラーミルなど） で行われる。また、固体微粒子分散する際に分散助剤を用いてもよい。
【００７１】
画像を向上させる「色調剤」として知られる添加剤を含むと光学濃度が高くなることがある。また、色調剤は黒色銀画像を形成させるうえでも有利になることがある。色調剤は画像形成層を有する面に銀１ モルあたりの０．１ 〜５０％ モルの量含まれることが好ましく、０．５ 〜２０％ モル含まれることがさらに好ましい。また、色調剤は現像時のみ有効に機能を持つように誘導化されたいわゆるプレカーサーであってもよい。
【００７２】
有機銀塩を利用した熱現像感光材料においては広範囲の色調剤が特開昭４６−６０７７ 号、同４７−１０２８２号、同４９−５０１９ 号、同４９−５０２０ 号、同４９−９１２１５号、同４９−９１２１５号、同５０−２５２４ 号、同５０−３２９２７号、同５０−６７１３２号、同５０−６７６４１号、同５０−１１４２１７ 号、同５１−３２２３ 号、同５１−２７９２３号、同５２−１４７８８号、同５２−９９８１３号、同５３−１０２０ 号、同５３−７６０２０号、同５４−１５６５２４ 号、同５４−１５６５２５ 号、同６１−１８３６４２ 号、特開平４−５６８４８ 号、特公昭４９−１０７２７号、同５４−２０３３３号、米国特許３，０８０，２５４ 号、同３，４４６，６４８ 号、同３，７８２，９４１ 号、同４，１２３，２８２ 号、同４，５１０，２３６ 号、英国特許１３８０７９５ 号、ベルギー特許８４１９１０号などに開示されている。色調剤の例は、フタルイミドおよびＮ−ヒドロキシフタルイミド；スクシンイミド、ピラゾリン−５− オン、ならびにキナゾリノン、３−フェニル−２− ピラゾリン−５− オン、１−フェニルウラゾール、キナゾリンおよび２，４−チアゾリジンジオンのような環状イミド；ナフタルイミド（ 例えば、Ｎ−ヒドロキシ−１，８− ナフタルイミド） ；コバルト錯体（ 例えば、コバルトヘキサミントリフルオロアセテート） ；３−メルカプト−１，２，４− トリアゾール、２，４−ジメルカプトピリミジン、３−メルカプト−４，５−−ジフェニル−１，２，４− トリアゾールおよび２，５−ジメルカプト−１，３，４− チアジアゾールに例示されるメルカプタン；Ｎ−（ アミノメチル） アリールジカルボキシイミド、（ 例えば、（Ｎ，Ｎ− ジメチルアミノメチル） フタルイミドおよびＮ，Ｎ−（ ジメチルアミノメチル）−ナフタレン−２，３− ジカルボキシイミド） ；ならびにブロック化ピラゾール、イソチウロニウム誘導体およびある種の光退色剤（ 例えば、Ｎ，Ｎ−ヘキサメチレンビス（１− カルバモイル−３，５− ジメチルピラゾール） 、１，８−（３，６− ジアザオクタン） ビス（ イソチウロニウムトリフルオロアセテート） および２−トリブロモメチルスルホニル）−（ ベンゾチアゾール））；ならびに３−エチル−５［（３−エチル−２− ベンゾチアゾリニリデン）−１−メチルエチリデン］−２−チオ−２，４− オキサゾリジンジオン；フタラジノン、フタラジノン誘導体もしくは金属塩、または４−（１− ナフチル） フタラジノン、６−クロロフタラジノン、５，７−ジメトキシフタラジノンおよび２，３−ジヒドロ−１，４− フタラジンジオンなどの誘導体；フタラジノンとフタル酸誘導体（ 例えば、フタル酸、４−メチルフタル酸、４−ニトロフタル酸およびテトラクロロ無水フタル酸など） との組合せ；フタラジン、フタラジン誘導体もしくは金属塩、または４−（１− ナフチル） フタラジン、６−クロロフタラジン、５，７−ジメトキシフタラジンおよび２，３−ジヒドロフタラジンなどの誘導体；フタラジンとフタル酸誘導体（ 例えば、フタル酸、４−メチルフタル酸、４−ニトロフタル酸およびテトラクロロ無水フタル酸など） との組合せ；キナゾリンジオン、ベンズオキサジンまたはナフトオキサジン誘導体；色調調節剤としてだけでなくその場でハロゲン化銀生成のためのハライドイオンの源としても機能するロジウム錯体、例えばヘキサクロロロジウム（ＩＩＩ） 酸アンモニウム、臭化ロジウム、硝酸ロジウムおよびヘキサクロロロジウム（ＩＩＩ）酸カリウムなど；無機過酸化物および過硫酸塩、例えば、過酸化二硫化アンモニウムおよび過酸化水素；１，３−ベンズオキサジン−２，４− ジオン、８− メチル−１，３− ベンズオキサジン−２，４− ジオンおよび６−ニトロ−１，３− ベンズオキサジン−２， ４−ジオンなどのベンズオキサジン−２，４− ジオン；ピリミジンおよび不斉− トリアジン（ 例えば、２，４−ジヒドロキシピリミジン、２−ヒドロキシ−４− アミノピリミジンなど） 、アザウラシル、およびテトラアザペンタレン誘導体（ 例えば、３，６−ジメルカプト−１，４− ジフェニル−１Ｈ，４Ｈ−２，３ａ，５，６ａ− テトラアザペンタレン、および１，４−ジ（ｏ− クロロフェニル）−３，６−ジメルカプト−１Ｈ，４Ｈ−２，３ａ，５，６ａ− テトラアザペンタレン） などがある。
【００７３】
本発明の色調剤は、溶液、粉末、固体微粒子分散物などいかなる方法で添加してもよい。固体微粒子分散は公知の微細化手段（ 例えば、ボールミル、振動ボールミル、サンドミル、コロイドミル、ジェットミル、ローラーミルなど） で行われる。また、固体微粒子分散する際に分散助剤を用いてもよい。
【００７４】
本発明における感光材料は、帯電防止または導電性層、例えば、可溶性塩（例えば塩化物、硝酸塩など）、蒸着金属層、米国特許第２，８６１，０５６号および同第３，２０６，３１２号に記載のようなイオン性ポリマーまたは米国特許第３，４２８，４５１号に記載のような不溶性無機塩などを含む層などを有してもよい。
【００７５】
本発明における熱現像感光材料を用いてカラー画像を得る方法としては特開平７−１３２９５号１０頁左欄４３行目から１１左欄４０行目に記載の方法がある。また、カラー染料画像の安定剤としては英国特許第１，３２６，８８９号、米国特許第３，４３２，３００号、同第３，６９８，９０９号、同第３，５７４，６２７号、同第３，５７３，０５０号、同第３，７６４，３３７号および同第４，０４２，３９４号に例示されている。
【００７６】
本発明における熱現像感光材料を構成する層は、浸漬コーティング、エアナイフコーティング、フローコーティングまたは、米国特許第２，６８１，２９４号に記載の種類のホッパーを用いる押出コーティングを含む種々のコーティング操作により被覆することができる。所望により、米国特許第２，７６１，７９１号および英国特許第８３７，０９５号に記載の方法により２層またはそれ以上の層を同時に被覆することができる。
【００７７】
本発明における熱現像写真材料の中に追加の層、例えば移動染料画像を受容するための染料受容層、反射印刷が望まれる場合の不透明化層、および光熱写真技術において既知のプライマー層などを含むことができる。本発明の感材はその感材一枚のみで画像形成できることが好ましく、受像層等の画像形成に必要な機能性層が別の感材とならないことが好ましい。
【００７８】
本発明の熱現像感光材料はいかなる方法で現像されても良いが、通常イメージワイズに露光した感光材料を昇温して現像される。好ましい現像温度としては８０〜２５０℃であり、さらに好ましくは１００〜１４０℃である。現像時間としては１〜１８０秒が好ましく、１０〜９０秒がさらに好ましい。
【００７９】
本発明の感光材料はいかなる方法で露光されても良いが、露光光源としてレーザー光が好ましい。本発明によるレーザー光としては、ガスレーザー、ＹＡＧレーザー、色素レーザー、半導体レーザーなどが好ましい。また、半導体レーザーと第２高調波発生素子などを用いることもできる。
【００８０】
本発明の感光材料は露光時のヘイズが低く、干渉縞が発生しやすい傾向にある。この干渉縞発生防止技術としては、特開平５−１１３５４８などに開示されているレーザー光を感光材料に対して斜めに入光させる技術や、ＷＯ９５／３１７５４などに開示されているマルチモードレーザーを利用する方法が知られており、これらの技術を用いることが好ましい。
【００８１】
本発明の熱現像感光材料には、種々の支持体を用いることができる。典型的な支持体は、ポリエステルフィルム、下塗りポリエステルフィルム、ポリエチレンテレフタレートフィルム、ポリエチレンナフタレートフィルム、硝酸セルロースフィルム、セルロースエステルフィルム、ポリビニルアセタールフィルム、ポリカーボネートフィルムならびにガラス、紙、金属なども含む。このうち２軸延伸したポリエチレンテレフタレートは強度、寸法安定性、耐薬品性などの点から好ましい。支持体は必要に応じて染色してもよい。
【００８２】
【実施例】
以下に実施例を挙げて本発明をさらに詳細に説明するが本発明はこれらに限定されるものではない。
【００８３】
実施例１
（ハロゲン化銀粒子Ａ の調製）
水７００ｍｌ にフタル化ゼラチン２２ｇ 及び臭化カリウム３０ｍｇを溶解して温度４０℃にてｐＨを５．０ に合わせた後、硝酸銀１８．６ｇ を含む水溶液１５９ｍｌ と臭化カリウムと沃化カリウムを９２：８ のモル比で含む水溶液をｐＡｇ７．７に保ちながらコントロールドダブルジェット法で１０分間かけて添加した。ついで硝酸銀５５．４ｇを含む水溶液４７６ｍｌ と六塩化イリジウム酸二カリウムを８ μモル／リットルと臭化カリウムを１モル／リットルで含む水溶液をｐＡｇ７．７に保ちながらコントロールドダブルジェット法で３０分間かけて添加した。その後ｐＨを下げて凝集沈降させ脱塩処理をし、フェノキシエタノール０．１ ｇを加え、 ｐＨ５．９、 ｐＡｇ８．０ に調製した。沃化銀含有量コア８ モル％、平均２モル％、粒子サイズ０．０７μｍ、投影面積直径の変動係数８ ％、（１００ ）面比率８６％の立方体粒子であった。
【００８４】
得られたハロゲン化銀粒子に対し、温度を６０℃に昇温して、銀１ モル当たりチオ硫酸ナトリウム８５μモルと２、３、４、５、６−ペンタフルオロフェニルジフェニルフォスフィンセレニドを１１μモル、２ μモルのテルル化合物１ 、塩化金酸３．３ μモル、チオシアン酸２３０ μモルを添加し、１２０ 分間熟成した。その後温度を５０℃に変更して増感色素Ａ をハロゲン化銀１モルに対して５ ×１０^ー４モル、増感色素Ｂ を２ ×１０^ー４モル攪拌しながら添加した。更に沃化カリウムをハロゲン化銀に対して３．５ モル％添加して３０分攪拌し、３０℃に急冷してハロゲン化銀粒子Ａ の調製を終了した。
【００８５】
【化２】

【００８６】
【化３】

【００８７】
（有機酸銀微結晶分散物の調製）
ベヘン酸４０ｇ、ステアリン酸７．３ ｇ、水５００ｍｌ を温度９０℃で１５分間攪拌し、１ＮーＮａＯＨ１８７ｍｌを１５分間かけて添加し、１Ｎの硝酸水溶液６１ｍｌを添加して５０℃に降温した。次に１Ｎ硝酸銀水溶液１２４ｍｌ を２ 分間かけて添加し、そのまま３０分間攪拌した。その後、吸引濾過で固形分を濾別し、濾水の伝導度３０μＳ ／ｃｍになるまで固形分を水洗した。こうして得られた固形分は、乾燥させないでウエットケーキとして取り扱い、乾燥固形分３４．８ｇ相当のウエットケーキに対し、ポリビニルアルコール１２ｇおよび水１５０ｍｌ 添加し、良く混合してスラリーとした。平均直径０．５ ｍｍのジルコニアビーズ８４０ ｇ用意してスラリーと一緒にベッセルに入れ、分散機（１ ／４ Ｇサンドグラインダーミル：アイメックス（株）製）にて５ 時間分散し、電子顕微鏡観察により平均短径０．０４μｍ，平均長径０．８ μｍ，投影面積変動係数３０％の針状粒子である有機酸銀の微結晶分散物の調製を終了した。
【００８８】
（還元剤固体微粒子分散物の調製）
下記還元剤１０ｇ に対してヒドロキシプロピルセルロース４ｇと水８６ｇ 添加して良く攪拌してスラリーとして１０時間放置した。その後、平均直径０．５ｍｍ のジルコニア製ビーズを１６８ｇ用意し、スラリーと一緒にベッセルに入れ、有機酸銀微結晶分散物の調製に用いたものと同じ分散機で１０時間分散して固体微粒子分散液を得た。平均粒子径は７０ｗｔ％が１．０ μｍ以下であった。
【００８９】
【化４】

【００９０】
（色調剤固体微粒子分散物の調製）
下記色調剤１、２の２．９ｇ 、２．１ｇ に対してそれぞれヒドロキシプロピルセルロース２ｇ と水９３ｇ 添加して良く攪拌して１０時間放置した。その後、平均直径０．５ｍｍ のジルコニア製ビーズを１６８ｇ 用意し、スラリーと一緒にベッセルに入れ、還元剤微結晶分散物の調製に用いたものと同じ分散機で１０時間分散して色調剤１および２の固体微粒子分散液を得た。平均粒子径は７０ｗｔ％が１．０ μｍ以下であった。
【００９１】
【化５】

【００９２】
（感光層塗布液の調製）
先に調製した有機銀微結晶分散物（銀１モル相当）に対し、ハロゲン化銀粒子Ａをハロゲン化銀１０モル％／有機酸銀相当と、以下のポリマーラテックスおよび素材を添加して感光層塗布液とした。

【００９３】
（表面保護層塗布液の調製）
イナードゼラチン１０ｇ に対し、界面活性剤Ａを０．２６ｇ 、界面活性剤Ｂを０．０９ｇ 、シリカ微粒子（平均粒子サイズ２．５μｍ ）０．９ｇ 、架橋剤（種類と添加量は表１の通り）、水１６４ｇ を添加して表面保護層塗布液とした。
【００９４】
【化６】

【００９５】
（発色剤分散物の調製）
酢酸エチル３５ｇ に対し、下記化合物１、２をそれぞれ２．５ｇ 、７．５ｇ 添加して攪拌して溶解した。その液にあらかじめ溶解したポリビニルアルコール１０重量％溶液を５０ｇ 添加し、５分間ホモジナイザーで攪拌した。その後、酢酸エチルを脱溶媒で揮発させ、最後に水で希釈し、発色剤分散物を調製した。
【００９６】
【化７】

【００９７】
（バック面塗布液の調製）
ポリビニルアルコール３０ｇに対し、先に調製した発色剤分散物５０ｇ、下記化合物２０ｇ、水２５０ｇを添加してバック面塗布液とした。
【００９８】
【化８】

【００９９】
（バック面保護層塗布液の調製）
イナートゼラチン１０ｇ に対し、界面活性剤Ａを０．２６ｇ 、界面活性剤Ｂを０．０９ｇ 、シリカ微粒子（平均粒径サイズ１２μｍ ）０．７ｇ 架橋剤（種類と添加量は表１の通り）、水１６４ｇ を添加して表面保護層塗布液とした。
【０１００】
【表１】

【０１０１】
（塗布サンプルの作成）
上記のように調整した感光層塗布液を、青色染料で色味付けした厚さ１７５ μｍの２軸延伸ポリエチレンテレフタレート支持体上に、銀の塗布量が１．９ｇ／ｍ^２となるように、そして感光層上に表面保護層塗布液をバインダーの塗布量が１．８ｇ／ｍ^２となるように塗布した。なお塗布は３層を１層づつ塗布して乾燥する方法（逐次塗布）と、３層を同時に塗布して乾燥する方法（同時塗布）のいずれかの方法で行った。試料はいずれも塗布後１０℃で１分間保持した後５０℃で２０分間乾燥した。乾燥後、感光層と反対の面上にバック面塗布液を６６０ｎｍの光学濃度０．７となるように、その上にバック面保護層塗布液をバインダーの塗布量が１．８ｇ／ｍ^２となるように２層を同時に塗布し１０℃で１分間保持した後５０℃で２０分乾燥して試料を作成した。
【０１０２】
この試料を２５℃６０％ＲＨの雰囲気下で１０日間保存した後以下の評価を実施した。結果を表１に示す。
【０１０３】
（含水率の評価）
感光層に用いたバインダーの溶液（または分散液）をガラス板上に塗布して５０℃で１時間乾燥し、厚さ約１００μｍ のポリマーモデル膜を作成した。その後、ポリマーモデル膜をガラス板から剥離し、２５℃６０％ＲＨの条件下で３日放置し重量（Ｗ_１ ）を測定した。ついでポリマーモデル膜を真空中に３日放置し、素早く重量の判っている秤量瓶に入れて重量（Ｗ_０ ＝Ｗ_３ −Ｗ_２ ）を測定した。ただし、Ｗ_３ はポリマーモデル膜と秤量瓶の重量、Ｗ_２ は秤量瓶の重量である。Ｗ_０ 、Ｗ_１ を用い、以下の色で含水率を求めた。
平衡含水率＝｛（Ｗ_１ −Ｗ_０ ）／Ｗ_０ ｝×１００（％）
【０１０４】
（写真性能の評価）
６４７ｎｍのＫｒレーザー感光計（最大出力５００ｍＷ ）で法線にたいして３０度の斜度で写真材料を露光した後、塗布試料を１２０℃で２０秒間現像処理し、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、Ｄｍｉｎ． 、Ｄｍａｘ． 、感度（Ｄｍｉｎ． より１．０高い濃度を与える露光量の比の逆数）で評価した。結果を表１に示した。感度については塗布試料１０１の感度を１００とした。
【０１０５】
（画像色調の評価）
写真性能の評価に用いた試料の最高濃度部の銀画像の色調を目視で評価した。
１：黒色
２：わずかに茶色味を帯びた黒色
３：茶色味を帯びた黒色
４：茶色
このうち実用上許容されるのは１、２に分類されるものである。
【０１０６】
（面状の評価）
試料の面状を目視評価して、以下のランクに分類した。
１：全面にわたり面状は良好
２：面状良好だが、塗布部両端にわずかな乱れ
３：全面にわたり若干の乱れ
４：全面にわたり著しい乱れ
これらのうち実用上許容されるのは、１、２に分類されるものである。
【０１０７】
（耐水性の評価）
写真性能評価に用いた現像処理後の試料の表面に蒸留水を０．２ｍｌ滴下して１分後にその部分をガーゼで拭いた。その後この部分の様子を以下のように分類した。
１：水滴の後がほとんど判らない
２：水滴の後がわずかに判る
３：水滴の後がへこんでいてはっきり判る
４：水滴の後の部分の表面保護層がなくなっている
このうち実用上許容されるのは、１、２に分類されるものである。
なお評価は感光層面とバック面の両方について行った。
【０１０８】
実施例２
実施例１で調製したハロゲン化粒子の調製において増感色素Ａ、Ｂの代わりに増感色素Ｃ、Ｄを用いることと、写真性能の評価において６４７ｎｍの代わりに８２０ｎｍのダイオードを備えたレーザー感光計を用いる以外は実施例１と同様にして実施例２を行ったところ評価したところ、実施例１と同様の結果が得られた。
【０１０９】
【化９】

【０１１０】
以上の結果から本発明の試料は、耐水性に優れ面状、写真性、画像色調が良好であり、本発明の効果は明らかである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photothermographic material, and more particularly to a photothermographic material having excellent water resistance on the surface of a photosensitive material after heat development.
[0002]
[Prior art]
A technique having a photosensitive layer on a support and converting a latent image formed by exposure to a visible image by heat development is well known.
[0003]
For example, U.S. Pat. Nos. 3,152,904, 3,457,075 and D.C. Morgan and B.M. “Thermal Processed Silver Systems” by Shelly (Imaging Processing and Materials), Necklet 8th Edition, S., W. Walworth. A. Shepp (2nd page, 1969)).
[0004]
These methods meet the social demands for simplification of processing and environmental protection, which have been increasing in recent years.
[0005]
Conventionally, these photothermographic materials have been coated with an organic solvent coating solution and dried to form a photosensitive layer. For example, US Pat. No. 5,415,993 discloses a polyvinyl butyral binder system using toluene and methyl ethyl ketone as solvents. However, it is not preferable to use an organic solvent from the viewpoints of environmental protection and safety. Thus, a technique for forming a photosensitive layer using an aqueous solvent has been devised. For example, Japanese Patent Application Laid-Open No. 53-116114 discloses gelatin coating, Japanese Patent Application Laid-Open No. 50-151138 discloses polyvinyl alcohol, and Japanese Patent Application Laid-Open No. 58-28737 discloses a technique for aqueous coating of a photosensitive layer binding polyvinyl acetal. Is described. Certainly, these systems can produce a light-sensitive material without using an organic solvent which is not preferable for the environment and safety. However, since the layer constituting the heat-developable photosensitive material is coated in an aqueous system, the water resistance of the heat-developable photosensitive material is low. It had the disadvantage of being insufficient. For example, such a photothermographic material has the disadvantage that the surface of the photosensitive material becomes extremely dirty if water is accidentally applied during use. Accordingly, a photothermographic material that does not have such drawbacks has been desired.
[0006]
[Problems to be solved by the present invention]
SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a photothermographic material having excellent surface and photographic properties and excellent water resistance.
[0007]
Another problem to be solved by the present invention is to provide a photothermographic material that can be produced by water-based coating that is preferable from the viewpoint of environmental protection and safety.
[0008]
[Means for Solving the Problems]
The above-mentioned problems are the following (1) to (6This is achieved by the present invention.
(1) It has a photosensitive layer containing at least one photosensitive silver halide on at least one surface of the support, a non-photosensitive surface protective layer, and an organic silver salt and a silver saltHindered phenol as reducing agentA photothermographic material containing a reducing agent, wherein the photosensitive layer satisfies the following conditions, and the non-photosensitive surface protective layer is crosslinked with a crosslinking agent.
a. More than 50 wt% of the binder is polymer latex.
b. A coating solution in which the binder is dispersed with a solvent containing 30 wt% or more of water is applied and then dried.
(2)The photothermographic material according to the above (1), wherein the hindered phenol reducing agent is bisphenol.
(3The above-mentioned (1), wherein the polymer latex polymer as the binder of the photosensitive layer is a polymer having an equilibrium water content of 2 wt% or less at 25 ° C. and 60% RH.Or (2)Photothermographic material.
(4The above (1), wherein the binder of the non-photosensitive surface protective layer contains 30 wt% or more of a hydrophilic polymer.Or any one of (3)Photothermographic material.
(5The above (wherein the hydrophilic polymer is gelatin)4) Photothermographic material.
(6(1) The photosensitive layer and the non-photosensitive surface protective layer are simultaneously dried after applying the coating solution.Or any one of (5)Photothermographic material.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
First, the photosensitive layer of the photothermographic material of the present invention will be described. The photosensitive layer of the photothermographic material of the present invention refers to a layer containing photosensitive silver halide among the layers constituting the photothermographic material of the present invention. In the photothermographic material of the present invention, there may be two or more photosensitive layers, and at least one of them is a photosensitive layer containing at least 50 wt% of the polymer latex described below. (Hereinafter, this photosensitive layer is referred to as “the photosensitive layer of the present invention”, and the polymer latex used as the binder is referred to as “the polymer latex of the present invention.”) However, the “polymer latex” as used herein refers to a fine water-insoluble hydrophobic polymer. The particles are dispersed in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, the emulsion is polymerized, the micelle is dispersed, or the polymer molecule has a partially hydrophilic structure and the molecular chain itself is molecularly dispersed. Anything may be used.
[0010]
As for the polymer latex of the present invention, “synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Kabushiki Kaisha (1978))”, “application of synthetic latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara) , Published by Polymer Press Association (1993)), “Synthetic Latex Chemistry (written by Soichi Muroi, published by Polymer Press Association (1970))”, and the like. The average particle size of the dispersed particles is preferably 1 to 50000 nm, more preferably about 5 to 1000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.
[0011]
The polymer latex of the present invention may be a so-called core / shell type latex other than a normal polymer latex having a uniform structure. In this case, it may be preferable to change the glass transition temperature between the core and the shell.
[0012]
The minimum film-forming temperature (MFT) of the polymer latex of the present invention is preferably -30 ° C to 90 ° C, more preferably about 0 ° C to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. A film-forming aid, also called a plasticizer, is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of polymer latex. "It is described in.
[0013]
Examples of the polymer species used in the polymer latex of the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof.
[0014]
The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is 5,000 to 1,000,000, preferably 10,000 to 100,000 in terms of number average molecular weight. When the molecular weight is too small, the mechanical strength of the photosensitive layer is insufficient, and when the molecular weight is too large, the film forming property is poor, which is not preferable.
[0015]
The polymer latex polymer used in the present invention preferably has an equilibrium water content at 25 ° C. and 60% RH of 2 wt% or less, more preferably 1 wt% or less. Although there is no restriction | limiting in particular in the minimum of an equilibrium moisture content, Preferably it is 0.01 wt%, More preferably, it is 0.03 wt%. For the definition and measurement method of the equilibrium moisture content, for example, “Polymer Engineering Course 14, Polymer Material Testing Method (Edited by Polymer Society, Jinshokan)” can be referred to.
[0016]
Specific examples of the polymer latex used as the binder of the photosensitive layer of the photothermographic material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2 ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, Methyl methacrylate / vinyl chloride / acrylic acid copolymer latex, vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer latex, and the like.
[0017]
Such polymers are also commercially available, and the following polymers can be used. For example, as an example of an acrylic resin, Sebian A-4635, 46583, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.), etc. FINETEX ES650, 611, 675, 850 (manufactured by Dainippon Ink Chemical Co., Ltd.), WD-size, WMS (manufactured by Eastman Chemical Co., Ltd.) and the like as polyurethane resins, HYDRAN AP10, 20, 30, 40 (more than large) As a rubber-based resin such as Nippon Ink Chemical Co., Ltd., LACSTAR 7310K, 3307K, 4700H, 7123C (above Dainippon Ink and Chemicals Co., Ltd.) <Nipol Lx416, 410, 438C, 2507, (above Nippon Zeon Co., Ltd.) )), Etc. G351, G576 (manufactured by Nippon Zeon Co., Ltd.) as fats, L502, L513 (manufactured by Asahi Kasei Kogyo Co., Ltd.), etc. as vinylidene chloride resins, Chemipearl S120, SA100 (above Mitsui Petrochemical Co., Ltd.) as olefin resins ) Made).
[0018]
These polymers may be used alone or in combination of two or more as required.
[0019]
In the photosensitive layer of the present invention, 50% by weight or more of the total binder is the polymer latex, but 70% by weight or more is preferably the polymer latex.
[0020]
If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, or hydroxypropyl methylcellulose may be added to the photosensitive layer of the present invention within a range of less than 50 wt% of the total binder. The amount of these hydrophilic polymers added is preferably 30 wt% or less of the total binder in the photosensitive layer.
[0021]
The photosensitive layer of the present invention is formed by applying an aqueous coating solution and then drying it. However, “aqueous” as used herein means that 30 wt% or more, preferably 50 wt% or more of the solvent (dispersion medium) of the coating solution is water. As components other than water in the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used.
[0022]
Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80 / 15/5, water / methanol / dimethylformamide = 90/5/5. (However, figures represent wt%.)
The photosensitive layer of the present invention has a total binder amount of 0.2 to 30 g / m.², More preferably 1-15m²The range of is preferable.
[0023]
If necessary, a reducing agent, an organic silver salt, a color toning agent, an antifogging agent, and the like may be added to the photosensitive layer of the present invention. Further, a dye for adjusting the color tone, a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the photosensitive layer of the present invention.
[0024]
The photothermographic material of the present invention may be provided with a photosensitive layer other than the “photosensitive layer of the present invention”, that is, a photosensitive layer that does not satisfy the above conditions. In this case, there are no restrictions on the binder, the solvent of the coating solution, and the like.
[0025]
Next, a non-photosensitive protective layer (hereinafter referred to as “surface protective layer”) provided on the outermost layer of the surface having the photosensitive layer of the photothermographic material of the present invention will be described. Although there is no restriction | limiting in particular in the binder of a surface protective layer, It is preferable to use a hydrophilic polymer.
[0026]
As the hydrophilic polymer, polymers such as gelatin, polyvinyl alcohol, casein, agar, gum arabic, hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl chloride, polymethacrylic acid, polyvinylidene chloride, and polyvinyl acetate can be used. it can. Of these, gelatin is most preferred. Any gelatin such as lime-processed gelatin or acid-processed gelatin may be used. Further, a gelatin derivative may be used. As a binder for the surface protective layer, a latex of a polymer such as ethyl acrylate may be added in addition to the hydrophilic polymer.
[0027]
The thickness of the surface protective layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.
[0028]
The surface protective layer of the present invention is preferably formed by applying the above aqueous coating solution and then drying it.
[0029]
The surface protective layer of the present invention is crosslinked with a crosslinking agent. There is no restriction | limiting in particular in the crosslinking agent used for bridge | crosslinking. Known cross-linking agents such as epoxy compounds, isocyanate compounds, melamine compounds, and phenol compounds can be used. In the case of an isocyanate compound, a blocked isocyanate may be used.
[0030]
When the binder of the surface protective layer is gelatin, a crosslinking agent such as an active halogen compound or a vinyl sulfone compound is preferable.
[0031]
When the binder for the surface protective layer is polyvinyl alcohol, boric acid is also a preferred crosslinking agent.
[0032]
Preferred crosslinking agents are described in, for example, “Crosslinking Agent Handbook” (published by Shinzo Yamashita, published by Taiseisha (1981)).
[0033]
The amount of the crosslinking agent added is preferably 0.5 to 30 wt%, more preferably 1 to 10 wt% of the binder of the non-photosensitive surface protective layer.
[0034]
Specific examples of the crosslinking agent that can be used for crosslinking the surface protective layer of the present invention include the following.
[0035]
[Chemical 1]

[0036]
If necessary, an organic silver salt, a reducing agent for the silver salt, a toning agent, an antifoggant, a matting agent, a dye, a slip agent, a surfactant, and the like may be added to the surface protective layer.
[0037]
As the matting agent used for the surface protective layer, fine particles such as polystyrene, polymethyl methacrylate and silica are preferable. The shape of the particles is not particularly limited, but spherical fine particles are preferable. The particle size of the matting agent is preferably 0.2 to 20 μm, more preferably about 0.5 to 10 μm. The addition amount of the matting agent cannot be generally specified depending on the layer constitution, thickness and purpose of use of the photothermographic material, but is 10 to 200 mg / m.², More preferably 20 to 100 mg / m²The degree is preferred.
[0038]
As the slip agent used for the surface protective layer, a compound known in the art such as silicon compound and paraffin may be used.
[0039]
In the photothermographic material of the invention, a back layer may be provided on the surface of the support opposite to the surface on which the photosensitive layer is coated.
[0040]
The binder for the back layer of the present invention is not particularly limited, and the polymers described for the binder for the surface protective layer can be used. Furthermore, the polymer latex described in the photosensitive layer as a binder, particularly a polymer latex having an equilibrium water content of 2 wt% or less at 25 ° C. and 60% RH is particularly preferable.
[0041]
The back layer of the present invention is preferably formed by applying and drying the aqueous coating solution described above.
[0042]
In the present invention, the back layer preferably has a maximum absorption in the desired wavelength range of 0.3 or more and 2 or less, more preferably 0.5 or more and 2 or less, and in the visible region after processing. The absorption is preferably 0.001 or more and less than 0.5, more preferably a layer having an optical density of 0.001 or more and less than 0.3.
[0043]
You may add mat agents, such as a silica and a polymethylmethacrylate, to the back layer of this invention as needed.
[0044]
A surfactant, a crosslinking agent, a slipping agent and the like may be further added to the back layer of the present invention as necessary.
[0045]
Also, a backside resistive heating layer as shown in US Pat. Nos. 4,460,681 and 4,374,921 can be provided.
[0046]
The thickness of the back layer of the present invention is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm.
[0047]
In the photothermographic material of the invention, a protective layer (back surface protective layer) may be provided on the back layer. The binder for the back surface protective layer is not particularly limited, and the polymers described for the back layer can be used, and among these, hydrophilic polymers are particularly preferable. The back protective layer of the present invention is also preferably formed by applying and drying the aqueous coating solution described above.
[0048]
The back protective layer of the present invention is preferably crosslinked in the same manner as the surface protective layer. As the crosslinking agent, those described above can be used. The above-mentioned matting agent, dye, sliding agent, surfactant and the like may be added to the back surface protective layer of the invention as necessary. The thickness of the back surface protective layer of the present invention is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.
[0049]
In the present invention, the back surface matte degree is preferably 250 seconds or less and 10 seconds or more, and more preferably 180 seconds or less and 50 seconds or more.
[0050]
Methods for forming photosensitive silver halide in the present invention are well known in the art, for example, the methods described in Research Disclosure No. 17029 of June 1978 and US Pat. No. 3,700,458. Can be used. Specific methods that can be used in the present invention include a method in which a part of silver of an organic silver salt is converted into photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin Alternatively, a method of preparing photosensitive silver halide grains by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing it with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of keeping the cloudiness after image formation low, specifically 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less, and still more preferably. It is preferably 0.02 μm or more and 0.12 μm or less. The grain size here means the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. Further, when the silver halide grain is a tabular grain, it means a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other non-normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it means the diameter when considering a sphere equivalent to the volume of silver halide grains.
[0051]
Examples of the shape of the silver halide grains include cubes, octahedrons, tabular grains, spherical grains, rod-shaped grains, and potato grains. In the present invention, cubic grains and tabular grains are particularly preferred. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can be preferably used. The surface index (Miller index) of the outer surface of the photosensitive halosaponified grain is not particularly limited, but the spectral sensitizing efficiency when adsorbed by the spectral sensitizing dye is high, and the ratio of the {100} plane is high. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of the Miller index {100} plane is determined by the T.K. using the adsorption dependency between the {111} plane and the {100} plane in the adsorption of the sensitizing dye. Tani; Imaging Sci. 29, 165 (1985). The halogen composition of the photosensitive silver halide is not particularly limited and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. In the present invention, silver bromide or silver iodobromide can be preferably used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%, more preferably from 0.1 mol% to 20 mol%. The distribution of the halogen composition in the grain may be uniform, the halogen composition may be changed stepwise, or may be continuously changed. High silver iodobromide grains can be used. In addition, silver halide grains preferably having a core / shell structure can be used. As the structure, core / shell particles having a preferably 2- to 5-fold structure, more preferably a 2- to 4-fold structure can be used.
[0052]
The photosensitive silver halide grain of the present invention preferably contains at least one metal complex selected from rhodium, rhenium, ruthenium, osnium, iridium, cobalt, mercury or iron. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 nmol to 10 mmol, and more preferably in the range of 10 nmol to 100 μmol, per mol of silver. As a specific metal complex structure, a metal complex having a structure described in JP-A-7-225449 can be used. For cobalt and iron compounds, hexacyano metal complexes can be preferably used. Specific examples include, but are not limited to, ferricyanate ions, ferrocyanate ions, hexacyanocobaltate ions, and the like. The phase containing the metal complex in the silver halide may be uniform, may be contained in the core part at a high concentration, or may be contained in the shell part at a high concentration, and is not particularly limited.
[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, but in the present invention, it may or may not be desalted.
[0054]
The photosensitive silver halide grains in the present invention are preferably chemically sensitized. As a preferable chemical sensitization method, a sulfur sensitization method, a selenium sensitization method and a tellurium sensitization method can be used as is well known in the art. Further, noble metal sensitization methods such as gold compounds, platinum, palladium, iridium compounds and reduction sensitization methods can be used. As the compound preferably used in the sulfur sensitization method, selenium sensitization method and tellurium sensitization method, known compounds can be used, but compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te Compounds having a bond, tellurocarboxylates, Te-organyl tellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium and the like can be used. Examples of compounds preferably used for the noble metal sensitization include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or US Pat. No. 2,448,060 and British Patent 618,061. The compound which has been used can be preferably used. As specific compounds of the reduction sensitization method, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. can be used in addition to ascorbic acid and thiourea dioxide. . Further, reduction sensitization can be carried out by ripening the emulsion while maintaining the pH at 7 or higher or pAg at 8.3 or lower. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.
[0055]
The amount of the photosensitive silver halide used in the present invention is preferably 0.01 moles to 0.5 moles or less, more preferably 0.02 moles to 0.3 moles per mole of the organic silver salt. It is preferably 0.03 mol or more and 0.25 mol or less. Regarding the mixing method and mixing conditions of photosensitive silver halide and organic silver salt prepared separately, the silver halide particles and organic silver salt prepared respectively are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. Or a method of preparing an organic silver salt by mixing photosensitive silver halide that has been prepared at any timing during the preparation of the organic silver salt. There is no particular limitation as long as it appears.
[0056]
As the silver halide preparation method of the present invention, a so-called hydration method in which a part of silver of the organic silver salt is halogenated with an organic or inorganic halide is also preferably used. The organic halide used here may be any compound as long as it is a compound that reacts with an organic silver salt to produce silver halide, but N-halogenoimide (N-bromosuccinimide etc.), halogenated quaternary nitrogen compound (odor) And tetrabutylammonium bromide), and an association of a halogenated quaternary nitrogen salt with a halogen molecule (pyridinium perbromide). The inorganic halogen compound may be any compound as long as it is a compound that reacts with an organic silver salt to produce silver halide, but alkali metal halide or ammonium (sodium chloride, lithium bromide, potassium iodide, ammonium bromide, etc.) ), Alkaline earth metal halides (calcium bromide, magnesium chloride, etc.), transition metal halides (ferric chloride, cupric bromide, etc.), metal complexes having a halogen ligand (sodium iridate bromide) , Ammonium rhodate, etc.) and halogen molecules (bromine, chlorine, iodine). Moreover, you may use desired organic inorganic halide together.
[0057]
In the present invention, the amount of halide added during the halide is preferably 1 to 500 mmol, more preferably 10 to 250 mmol as a halogen atom per mol of the organic silver salt.
[0058]
The organic silver salt that can be used in the present invention is relatively stable to light, but is 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. It is a silver salt that forms a silver image when heated above. The organic silver salt may be any organic material containing a source capable of reducing silver ions. Silver salts of organic acids, particularly silver salts of long-chain fatty carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Also preferred are organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. The silver supply material can preferably constitute about 5 to 70% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the aliphatic carboxylic acid silver salt include silver behenate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, and tartaric acid. Including silver, silver linoleate, silver butyrate and silver camphorate, mixtures thereof, and the like.
[0059]
Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used. Preferred examples of these compounds include silver salt of 3-mercapto-4-phenyl-1,2,4-triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, 2 Silver salt of-(ethylglycolamide) benzothiazole, silver salt of thioglycolic acid such as silver salt of S-alkylthioglycolic acid (wherein the alkyl group has 12 to 22 carbon atoms), silver salt of dithioacetic acid, etc. Silver salt of dithiocarboxylic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, US Patent No. Silver salts described in US Pat. No. 4,123,274, for example, 3-amino-5-benzylthio-1,2,4-thiazole Silver salt of 1,2,4-mercaptothiazole derivative such as silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in US Pat. No. 3,301,678 Silver salts of thione compounds such as Furthermore, a compound containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, US Patent No. 4,220,709, 1,2,4-triazole or 1-H-tetrazole silver salt, imidazole and silver salt of imidazole derivative. For example, various silver acetylide compounds as described in U.S. Pat. Nos. 4,761,361 and 4,775,613 can also be used.
[0060]
Although there is no restriction | limiting in particular as a shape of the organic silver salt which can be used for this invention, The acicular crystal | crystallization which has a short axis and a long axis is preferable. In the present invention, the minor axis is preferably from 0.01 μm to 0.20 μm, the major axis is from 0.10 μm to 5.0 μm, the minor axis is from 0.01 μm to 0.15 μm, and the major axis is from 0.10 μm to 4. 0 μm or less is more preferable. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion is preferably 100% or less, more preferably 80% or less, and even more preferably 50% of the value obtained by dividing the standard deviation of the lengths of the short and long axes by the short and long axes. It is as follows. The method for measuring the shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring monodispersity, there is a method for obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the 100 fraction (variation coefficient) of the value divided by the volume-weighted average diameter is preferably 100% or less. More preferably, it is 80% or less, More preferably, it is 50% or less. As a measuring method, for example, it is obtained from the particle size (volume load average diameter) obtained by irradiating the organic silver salt dispersed in the liquid with laser light and calculating the autocorrelation function for the time change of the fluctuation of the scattered light. Can do.
[0061]
The organic silver salt that can be used in the present invention can be preferably desalted. There is no particular limitation on the method for performing desalting, and a known method can be used, but a known filtration method such as circular filtration, suction filtration, ultrafiltration, and flock-forming water washing by agglomeration method can be preferably used. .
[0062]
For the purpose of obtaining fine particles having a small particle size and no aggregation, the organic silver salt that can be used in the present invention is a method of forming a solid fine particle dispersion using a dispersant. The method of dispersing the organic silver salt in the form of fine solid particles is performed by using a known refinement means (for example, ball mill, vibration ball mill, planetary ball mill, sand mill, colloid mill, jet mill, roller mill) in the presence of a dispersion aid. Can be dispersed.
[0063]
When organic silver salt is made into solid fine particles using a dispersant, for example, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, maleic acid monoester copolymer, acryloylmethylpropane sulfonic acid Synthetic anionic polymers such as copolymers, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethylcellulose, anionic polymers such as alginic acid and pectic acid, anions described in JP-A-52-92716, WO88 / 04794, etc. Surfactants, compounds described in Japanese Patent Application No. 7-350753, or known anionic, nonionic, cationic surfactants, and other polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl Known polymers Le cellulose, or a polymer compound existing in nature such as gelatin can be suitably selected and used.
[0064]
Dispersing aid is generally mixed with organic silver salt powder or wet cake organic silver salt before dispersion, and sent to the disperser as a slurry. It is good also as an organic silver salt powder or a wet cake by heat-treating and the process by a solvent. The pH may be controlled with an appropriate pH adjuster before, during or after dispersion.
[0065]
In addition to mechanical dispersion, it may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersion aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the formation of fine particles.
[0066]
The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a gelatinized state using gelatin) with a hydrophilic colloid. You can also In addition, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.
[0067]
The organic silver salt of the present invention can be used in a desired amount, but is 0.1 to 5 g / m.²Is more preferable, and more preferably 1 to 3 g / m.²It is.
[0068]
Reducing agents for organic silver salts are hindered phenol reducing agents that reduce silver ions to metallic silver.Used. The reducing agent is preferably contained in an amount of 5 to 50% by mole, more preferably 10 to 40% by mole, based on 1 mole of silver on the surface having the image forming layer. The addition layer of the reducing agent may be any layer on the surface having the image forming layer. When added to a layer other than the image forming layer, it is preferably used in an amount of 10 to 50% mol per mol of silver. The reducing agent may be a so-called precursor that is derivatized so as to have an effective function only during development.
[0069]
As a hindered phenol reducing agentBisphenols such as bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2 -t-butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl) -4-hydroxyphenyl) propane and the like.
[0070]
The reducing agent of the present invention may be added by any method such as a solution, a powder, or a solid fine particle dispersion. The solid fine particle dispersion is performed by a known finer means (for example, ball mill, vibration ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). A dispersion aid may be used when dispersing the solid fine particles.
[0071]
Inclusion of an additive known as a “toning agent” that improves the image may increase the optical density. The toning agent may also be advantageous in forming a black silver image. The color toning agent is preferably included in the surface having the image forming layer in an amount of 0.1 to 50% mol, more preferably 0.5 to 20% mol per mol of silver. The toning agent may be a so-called precursor that is derivatized so as to have an effective function only during development.
[0072]
In a photothermographic material using an organic silver salt, a wide range of toning agents are disclosed in JP-A-46-6077, 47-10282, 49-5019, 49-5020, 49-91215, 49-91215, 50-2524, 50-32927, 50-67132, 50-67641, 50-114217, 51-3223, 51-27923, 52- 14788, 52-99813, 53-1020, 53-76020, 54-156524, 54-156525, 61-183642, JP-A-4-56848, JP-B-49- 10727, 54-20333, U.S. Pat.Nos. 3,080,254, 3,446,648, 3,782,941, No. 4,123,282, No. 4,510,236, British Patent No. 1380795, Belgian Patent No. 841910, and the like. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione Cyclic imides such as: naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4 -Mercaptans exemplified by dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryl Dicarboximide, (for example (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg , N, N-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)- (Benzothiazole)); and 3-ethyl-5 [(3-ethyl-2-benzothiazolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivatives or metals Salt, or 4- (1-naphthyl) Derivatives such as radinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride, etc.); phthalazine, phthalazine derivatives or metal salts, or 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2, Derivatives such as 3-dihydrophthalazine; combinations of phthalazine and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); quinazolinedione, benzoxazine or naphthoxazine derivatives Only as a color tone regulator Rhodium complexes that also serve as a source of halide ions for in situ silver halide formation, such as ammonium hexachlororhodium (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodium (III); inorganic peroxidation And persulfates, such as ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6- Benzoxazine-2,4-diones such as nitro-1,3-benzoxazine-2,4-dione; pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc. ), Azauracil, and tetraazapentalene derivatives ( For example, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4-di (o-chlorophenyl) -3,6-dimercapto-1H , 4H-2,3a, 5,6a-tetraazapentalene) and the like.
[0073]
The toning agent of the present invention may be added by any method such as a solution, a powder, or a solid fine particle dispersion. The solid fine particle dispersion is performed by a known finer means (for example, ball mill, vibration ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). A dispersion aid may be used when dispersing the solid fine particles.
[0074]
The light-sensitive material in the present invention is an antistatic or conductive layer such as a soluble salt (for example, chloride, nitrate, etc.), a vapor-deposited metal layer, U.S. Pat. Nos. 2,861,056 and 3,206,312. It may have a layer containing an ionic polymer as described or an insoluble inorganic salt as described in US Pat. No. 3,428,451.
[0075]
As a method for obtaining a color image using the photothermographic material in the invention, there is a method described in JP-A-7-13295, page 10, left column, line 43 to 11, left column, line 40. Examples of color dye image stabilizers include British Patent No. 1,326,889, US Pat. No. 3,432,300, US Pat. No. 3,698,909, US Pat. No. 3,574,627, US Pat. 3,573,050, 3,764,337 and 4,042,394.
[0076]
The layers constituting the photothermographic material of the present invention are coated by various coating operations 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. can do. If desired, two or more layers can be coated simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095.
[0077]
Includes additional layers in the photothermographic material of the present invention, such as a dye receiving layer for receiving a moving dye image, an opacifying layer when reflective printing is desired, and a primer layer known in the photothermographic art. be able to. The light-sensitive material of the present invention can preferably form an image with only one light-sensitive material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another light-sensitive material.
[0078]
The photothermographic material of the present invention may be developed by any method, but is usually developed by raising the temperature of the photosensitive material exposed imagewise. The preferred development temperature is 80 to 250 ° C, more preferably 100 to 140 ° C. The development time is preferably 1 to 180 seconds, and more preferably 10 to 90 seconds.
[0079]
The light-sensitive material of the present invention may be exposed by any method, but laser light is preferred as the exposure light source. As the laser beam according to the present invention, a gas laser, a YAG laser, a dye laser, a semiconductor laser and the like are preferable. A semiconductor laser and a second harmonic generation element can also be used.
[0080]
The photosensitive material of the present invention has a low haze upon exposure and tends to generate interference fringes. As this interference fringe generation prevention technology, a laser beam disclosed in Japanese Patent Laid-Open No. 5-113548 is incident obliquely on the photosensitive material, or a multimode laser disclosed in WO95 / 31754 is used. Methods are known and these techniques are preferably used.
[0081]
Various supports can be used in the photothermographic material of the invention. Typical supports also include polyester films, primed polyester films, polyethylene terephthalate films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, polyvinyl acetal films, polycarbonate films as well as glass, paper, metals and the like. Among these, biaxially stretched polyethylene terephthalate is preferable in terms of strength, dimensional stability, chemical resistance, and the like. The support may be dyed as necessary.
[0082]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
[0083]
Example 1
(Preparation of silver halide grains A)
After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 700 ml of water and adjusting the pH to 5.0 at a temperature of 40 ° C., 159 ml of an aqueous solution containing 18.6 g of silver nitrate, and potassium bromide and potassium iodide in 92: An aqueous solution containing a molar ratio of 8 was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. Next, 476 ml of an aqueous solution containing 55.4 g of silver nitrate and an aqueous solution containing 8 μmol / liter of dipotassium hexachloroiridate and 1 mol / liter of potassium bromide were maintained for 30 minutes by the controlled double jet method while maintaining pAg 7.7. Added. Thereafter, the pH was lowered to cause coagulation sedimentation, followed by desalting, and 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg 8.0. Cubic grains having a silver iodide content core of 8 mol%, an average of 2 mol%, a grain size of 0.07 μm, a coefficient of variation of projected area diameter of 8%, and a (100) plane ratio of 86%.
[0084]
With respect to the obtained silver halide grains, the temperature was raised to 60 ° C., and 85 μmol of sodium thiosulfate and 11 μl of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide per 1 mol of silver. Mole, 2 μmol of tellurium compound 1, 3.3 μmol of chloroauric acid and 230 μmol of thiocyanic acid were added and aged for 120 minutes. Thereafter, the temperature was changed to 50 ° C., and sensitizing dye A 5 × 10 × 1 mol of silver halide.^-4Mol, sensitizing dye B 2 × 10^-4Added with molar stirring. Further, 3.5 mol% of potassium iodide was added to the silver halide, stirred for 30 minutes, and rapidly cooled to 30 ° C. to complete the preparation of silver halide grains A 1.
[0085]
[Chemical 2]

[0086]
[Chemical 3]

[0087]
(Preparation of organic acid silver microcrystal dispersion)
40 g of behenic acid, 7.3 g of stearic acid, and 500 ml of water were stirred at 90 ° C. for 15 minutes, 187 ml of 1N NaOH was added over 15 minutes, 61 ml of 1N nitric acid aqueous solution was added, and the temperature was lowered to 50 ° C. Next, 124 ml of 1N silver nitrate aqueous solution was added over 2 minutes, and the mixture was stirred for 30 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed until the filtrate had a conductivity of 30 μS / cm. The solid content thus obtained was handled as a wet cake without being dried, and 12 g of polyvinyl alcohol and 150 ml of water were added to the wet cake equivalent to 34.8 g of the dry solid content and mixed well to obtain a slurry. Prepare 840 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and disperse for 5 hours with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.). Preparation of a microcrystalline dispersion of organic acid silver which is needle-like particles having an average minor axis of 0.04 μm, an average major axis of 0.8 μm, and a projected area variation coefficient of 30% was completed.
[0088]
(Preparation of reducing agent solid fine particle dispersion)
To 10 g of the following reducing agent, 4 g of hydroxypropylcellulose and 86 g of water were added and stirred well and left as a slurry for 10 hours. Thereafter, 168 g of zirconia beads having an average diameter of 0.5 mm were prepared, put into a vessel together with the slurry, and dispersed for 10 hours with the same disperser used for the preparation of the organic acid silver microcrystal dispersion. A liquid was obtained. As for the average particle diameter, 70 wt% was 1.0 μm or less.
[0089]
[Formula 4]

[0090]
(Preparation of colorant solid fine particle dispersion)
2 g of hydroxypropylcellulose and 93 g of water were added to 2.9 g and 2.1 g of the following toning agents 1 and 2, and the mixture was well stirred and left for 10 hours. Thereafter, 168 g of zirconia beads having an average diameter of 0.5 mm were prepared, put into a vessel together with the slurry, and dispersed for 10 hours with the same disperser used for the preparation of the reducing agent microcrystal dispersion. 2 solid fine particle dispersion was obtained. As for the average particle diameter, 70 wt% was 1.0 μm or less.
[0091]
[Chemical formula 5]

[0092]
(Preparation of photosensitive layer coating solution)
To the organic silver microcrystal dispersion (equivalent to 1 mol of silver) prepared earlier, 10 mol% of silver halide grains / equivalent to organic acid silver, and the following polymer latex and materials were added to the photosensitive layer. A coating solution was obtained.

[0093]
(Preparation of surface protective layer coating solution)
0.26 g of surfactant A, 0.09 g of surfactant B, 0.9 g of silica fine particles (average particle size 2.5 μm), 10 g of inert gelatin, cross-linking agent (type and amount of addition are shown in Table 1) And 164 g of water was added to prepare a surface protective layer coating solution.
[0094]
[Chemical 6]

[0095]
(Preparation of color former dispersion)
2.5 g and 7.5 g of the following compounds 1 and 2 were added to 35 g of ethyl acetate and dissolved by stirring. 50 g of a 10% by weight solution of polyvinyl alcohol previously dissolved in the solution was added and stirred for 5 minutes with a homogenizer. Thereafter, ethyl acetate was volatilized by removing the solvent, and finally diluted with water to prepare a color former dispersion.
[0096]
[Chemical 7]

[0097]
(Preparation of back surface coating solution)
50 g of the color former dispersion prepared above, 20 g of the following compound, and 250 g of water were added to 30 g of polyvinyl alcohol to prepare a back surface coating solution.
[0098]
[Chemical 8]

[0099]
(Preparation of back surface protective layer coating solution)
10 g of inert gelatin, 0.26 g of surfactant A, 0.09 g of surfactant B, 0.7 g of silica fine particles (average particle size 12 μm), cross-linking agent (type and amount added are as shown in Table 1), 164 g of water was added to prepare a surface protective layer coating solution.
[0100]
[Table 1]

[0101]
(Creation of application sample)
On the 175 μm thick biaxially stretched polyethylene terephthalate support obtained by tinting the photosensitive layer coating solution prepared as described above with a blue dye, the silver coating amount was 1.9 g / m.²And the coating amount of the surface protective layer coating solution on the photosensitive layer is 1.8 g / m.²It applied so that it might become. The coating was carried out by either a method of coating and drying three layers one by one (sequential coating) or a method of coating and drying three layers simultaneously (simultaneous coating). Each sample was held at 10 ° C. for 1 minute after coating and then dried at 50 ° C. for 20 minutes. After drying, the back surface coating solution is applied onto the surface opposite to the photosensitive layer so that the optical density of 660 nm is 0.7, and the coating amount of the binder on the back surface protective layer is 1.8 g / m.²Two layers were simultaneously applied so that the sample was held at 10 ° C. for 1 minute and then dried at 50 ° C. for 20 minutes to prepare a sample.
[0102]
This sample was stored for 10 days in an atmosphere of 25 ° C. and 60% RH, and the following evaluation was performed. The results are shown in Table 1.
[0103]
(Evaluation of moisture content)
The binder solution (or dispersion) used for the photosensitive layer was applied onto a glass plate and dried at 50 ° C. for 1 hour to prepare a polymer model film having a thickness of about 100 μm. Thereafter, the polymer model film is peeled off from the glass plate, and left for 3 days under the condition of 25 ° C. and 60% RH.₁  ) Was measured. The polymer model membrane is then left in a vacuum for 3 days and quickly placed in a weighing bottle of known weight (W₀  = W₃  -W₂  ) Was measured. However, W₃  Is the weight of the polymer model membrane and weighing bottle, W₂  Is the weight of the weighing bottle. W₀  , W₁  The water content was determined with the following colors.
Equilibrium moisture content = {(W₁  -W₀  ) / W₀  } × 100 (%)
[0104]
(Evaluation of photographic performance)
After the photographic material was exposed at an inclination of 30 degrees with respect to the normal line with a 647 nm Kr laser sensitometer (maximum output 500 mW), the coated sample was developed at 120 ° C. for 20 seconds, and the resulting image was evaluated by a densitometer. went. The result of the measurement is Dmin. , Dmax. , And the sensitivity (reciprocal of the ratio of the exposure amount giving a density 1.0 higher than Dmin.). The results are shown in Table 1. Regarding the sensitivity, the sensitivity of the coated sample 101 was set to 100.
[0105]
(Evaluation of image color tone)
The color tone of the silver image at the highest density portion of the sample used for evaluation of photographic performance was visually evaluated.
1: Black
2: Slightly brownish black
3: Blackish brownish
4: Brown
Of these, those which are practically acceptable are classified into 1 and 2.
[0106]
(Surface evaluation)
The surface state of the sample was visually evaluated and classified into the following ranks.
1: Good surface shape over the entire surface
2: Surface condition is good, but slight disturbance at both ends
3: Slight disturbance over the entire surface
4: Significant disorder over the entire surface
Among these, those that are practically acceptable are classified into 1 and 2.
[0107]
(Evaluation of water resistance)
0.2 ml of distilled water was dropped on the surface of the developed sample used for photographic performance evaluation, and the portion was wiped with gauze one minute later. After that, the state of this part was classified as follows.
1: After the water drop is almost unknown
2: Slightly understood after water drop
3: The back of the water drop is dented and clearly understood
4: The surface protective layer after the water drop is gone
Among these, those that are practically acceptable are classified into 1 and 2.
The evaluation was performed on both the photosensitive layer surface and the back surface.
[0108]
Example 2
In the preparation of the halogenated particles prepared in Example 1, the sensitizing dyes C and D are used in place of the sensitizing dyes A and B, and the laser sensitometer having a 820 nm diode instead of 647 nm in the evaluation of photographic performance. When Example 2 was conducted in the same manner as in Example 1 except that was used, evaluation was made and results similar to those in Example 1 were obtained.
[0109]
[Chemical 9]

[0110]
From the above results, the sample of the present invention is excellent in water resistance, has excellent surface properties, photographic properties, and image tone, and the effects of the present invention are clear.

Claims (6)

A photosensitive layer containing at least one photosensitive silver halide on at least one surface of the support and a non-photosensitive surface protective layer, an organic silver salt and a hindered phenol reducing agent as a reducing agent for the silver salt A photothermographic material containing the photothermographic material, wherein the photosensitive layer satisfies the following conditions, and the non-photosensitive surface protective layer is crosslinked with a crosslinking agent.
a. More than 50 wt% of the binder is polymer latex.
b. A coating solution in which the binder is dispersed with a solvent containing 30 wt% or more of water is applied and then dried. 2. The photothermographic material according to claim 1, wherein the hindered phenol reducing agent is bisphenol. 3. The photothermographic material according to claim 1, wherein the polymer latex polymer as a binder of the photosensitive layer is a polymer having an equilibrium water content of 2 wt% or less at 25 ° C. and 60% RH. 4. The photothermographic material according to claim 1, wherein the binder of the non-photosensitive surface protective layer contains 30 wt% or more of a hydrophilic polymer. 5. The photothermographic material according to claim 4 , wherein the hydrophilic polymer is gelatin. Wherein after the photosensitive layer non-light-sensitive surface protective layer coating the coating liquid, heat-developable photosensitive material of any one of claims 1 to 5 are dried at the same time.