JP3575639B2 - Method for producing silver halide grains and silver halide emulsion - Google Patents

Description

【００１１】
ここでＲ^０ はＨ、または少なくとも１つの極性基を有する炭素数１〜１０の炭化水素（例えば−ＣＨ_２ＯＨ、−Ｃ_２Ｈ_５ＯＨ 、−ＣＨ_２−Ｏ−ＣＨ_３） で、好ましくはＨである。Ｒは炭素数３〜１０のアルキレン基を表す。
ｎ、ｍは繰返し単位の平均数を表わし、前記分子量規定を満たす４以上の値である。
【００１２】
【化５】

【００１３】
ここでＬＰＵはＨＯ−ＨＰＥＯＵ−基およびＨＯ−ＬＰＡＯＵ−基以外の親油性基を指し、置換または無置換のアルキル基、アルケニル基、アリール基、ヘテロ環基、アルコキシ基、アリーロキシ基、アシル基、アシルアミノ基、アルキルチオ基、アリールチオ基、アルコキシカルボニル基、アリーロキシカルボニル基、アリサイクリック基を指す。なお、ＨＰＥＯＵ、ＬＰＡＯＵは一般式（１）−ａ）、（１）−ｂ）と同義である。ＬＰＵ′はＨ、炭素数１〜２０のアルキル基を指す。
【００１４】
（３） 該分散媒溶液が一般式（３）で表されるモノマーの繰返し単位を１重量％以上含有する重合体の少なくとも１種を０．０１ｇ／リットル以上含有し、該重合体の分子量が５００〜１０^６ である事を特徴とする前記（１） 記載のハロゲン化銀粒子の製造方法。
【００１５】
【化６】

【００１６】
式中Ｒ^１ はＨ、炭素数１〜４の低級アルキル基を表し、Ｒ^２ は炭素数１〜２０の１価の置換基を表す。Ｒ^３ は炭素数３〜１０のアルキレン基を表し、Ｌは２価の連結基を表す。ｎは繰返し単位の平均数を表し、４〜６００である。
【００１７】
（４） 該分散媒溶液が一般式（３）で表わされるモノマーと一般式（４）で表わされるモノマーの少なくとも２種をそれぞれ１重量％以上含有する共重合体を０．０１ｇ／リットル以上含有し、該共重合体の分子量が５００〜１０^６ である事を特徴とする前記（１） 記載のハロゲン化銀粒子の製造方法。
一般式（４） ＣＨ_２ ＝Ｃ（Ｒ^４ ）−Ｌ′−（ＣＨ_２ ＣＨ_２ Ｏ）_ｍ −Ｒ^５
式中、Ｒ^４ はＨ、炭素数１〜４の低級アルキル基を表し、Ｒ^５ は炭素数１〜２０の１価の置換基を表し、Ｌ′は２価の連結基を表す。ｍは繰返し単位の平均数を表し、４〜６００である。
【００１８】
（５） 該分散媒溶液が下記一般式（５）で表される繰返し単位を１重量％以上含有する重合体の少なくとも１種と、一般式（６）で表される繰返し単位を１重量％以上含有する重合体の少なくとも１種をそれぞれ０．０１ｇ／リットル以上含有し、それぞれの重合体の分子量が５００〜１０^６ である事を特徴とする前記（１） 記載のハロゲン化銀粒子の製造方法。
一般式（５） −（Ｒ−Ｏ）_ｎ −
一般式（６） −（ＣＨ_２ ＣＨ_２ Ｏ）_ｍ −
式中、Ｒは炭素数３〜１０のアルキレン基を表わす。
ｎ、ｍは繰返し単位の平均数を表し、該分子量規定を満たす４以上の値である。
【００１９】
（６） 該一般式（５）で表される繰返し単位を有する重合体が下記一般式（７）−（ａ）で表されるモノマーを構成成分とするビニル重合体および一般式（７）−（ｂ）で表されるポリウレタンを含む重合体から選ばれる少なくとも１種の重合体であり、該一般式（６）で表わされる繰返し単位を有する重合体が下記一般式（７）−（ｃ）で表されるモノマーを構成成分とするビニル重合体、一般式（７）−（ｄ）で表されるポリウレタンを含む重合体、および置換または未置換のポリエチレングリコールから選ばれる少なくとも１種の重合体であることを特徴とする前記（５） に記載のハロゲン化銀粒子の製造方法。
一般式（７）−ａ） ＣＨ_２ ＝Ｃ（Ｒ^１ ）−Ｌ−（Ｒ^３ −Ｏ）_ｎ −Ｒ^２
一般式（７）−ｂ）
−〔Ｏ −（Ｒ−Ｏ）_ｎ 〕_ｘ −〔Ｏ − Ｒ^１１−Ｏ 〕_ｙ −〔ＣＯＮＨ−Ｒ^１２−ＮＨＣＯ 〕_Ｚ −
一般式（７）−ｃ） ＣＨ_２ ＝Ｃ（Ｒ^４ ）−Ｌ′−（ＣＨ_２ ＣＨ_２ Ｏ）_ｍ −Ｒ^５
一般式（７）−ｄ）
−〔Ｏ−（ＣＨ_２ＣＨ_２Ｏ） _ｍ 〕_Ｘ’−〔Ｏ−Ｒ^１３−Ｏ 〕 _ｙ’ −〔ＣＯＮＨ−Ｒ^１４−ＮＨＣＯ 〕_Ｚ’−
式中、ｎ、ｍは繰返し単位の平均数を表し、４〜６００である。Ｒ^１ 、Ｒ^４ はＨまたは炭素数１〜４の低級アルキル基を表す。Ｒ^２ 、Ｒ^５ はＨまたは炭素数１〜２０の１価の置換基を表す。Ｌ、Ｌ′は２価の連結基を表す。Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４は２価の連結基を表し、炭素数１〜２０のアルキレン基、炭素数６〜２０のフェニレン基、または炭素数７〜２０のアラルキレン基を表す。ｘ、ｙ、ｚ、ｘ′、ｙ′、ｚ′は各成分の重量百分率を表し、ｘ、ｘ′は１〜７０、ｙ、ｙ′は１〜７０、ｚ、ｚ′は２０〜７０を表す。ここでｘ＋ｙ＋ｚ＝１００、ｘ′＋ｙ′＋ｚ′＝１００である。Ｒは炭素数３〜１０のアルキレン基を表す。
【００２０】
（７） 該平板粒子の主平面が｛１００｝面かまたは｛１１１｝面であり、該粒子の直径分布の変動係数（標準偏差／平均直径）が０〜０．３である事を特徴とする前記１〜６記載のハロゲン化銀粒子の製造方法。
（８） 少なくとも分散媒とハロゲン化銀粒子を有するハロゲン化銀乳剤において、該ハロゲン化銀粒子の全投影面積の７５〜１００％が厚さが０．０２〜０．３μｍ、アスペクト比（直径／厚さ）が２〜５０の平板粒子であり、該粒子の直径分布の変動係数（標準偏差／平均直径）が０〜０．３であり、該分散媒の３０〜１００重量％が（化学修飾された−ＮＨ_２ 基数の％とメチオニン含率の関係が図１のａ_１ の領域にあるゼラチン）である事を特徴とするハロゲン化銀乳剤。
【００２１】
その他、本発明の好ましい態様は次の通り。
（９） 少なくとも分光増感色素を吸着したハロゲン化銀粒子と、分散媒を有するハロゲン化銀乳剤において、該ハロゲン化銀粒子の投影面積の７５〜１００％がアスペクト比が２〜５０、厚さが０．０２〜０．３μｍの平板粒子であり、その直径分布の変動係数が０〜０．３、分光増感色素の吸着被覆率の変動係数が０〜０．３である事を特徴とするハロゲン化銀乳剤。
（１０）該平板粒子が少なくとも１０^−７ｍｏｌ／ｍｏｌ Ａｇ以上でセレン増感されており、かつ、該平板粒子のＳｅの含有率が該平板粒子の表面積に比例しており、該比例定数の粒子間バラツキの変動係数が０〜０．３である事を特徴とする前記（９） 記載のハロゲン化銀乳剤。
（１１）該平板粒子が少なくとも１０^−７ｍｏｌ／ｍｏｌ Ａｇ以上で金増感されており、かつ、該平板粒子の金の含有率が該平板粒子の表面積に比例しており、該比例定数の粒子間バラツキの変動係数が０〜０．３である事を特徴とする前記（９） 、（１０）記載のハロゲン化銀乳剤。
【００２２】
以下に本発明を更に詳細に説明する。
Ａ．平板粒子
該平板粒子は主平面が｛１００｝面の平板粒子（以後、「（１００）平板粒子」と記す）と、｛１１１｝面の平板粒子（以後、「（１１１）平板粒子」と記す）を挙げる事ができる。
該平板粒子は厚さが０．０２〜０．３μｍ、好ましくは０．０２〜０．１５μｍ、より好ましくは０．０３〜０．１０μｍ、最も好ましくは０．０４〜０．０８μｍである。アスペクト比（直径／厚さ）は２〜５０、好ましくは３〜３０である。直径分布の変動係数（分布の標準偏差／平均直径）（以後、「Ｃ．Ｖ．値」と記す）は０〜０．３が好ましく、０〜０．２がより好ましく、０〜０．１が更に好ましく、０〜０．０８が最も好ましい。ここで直径とは粒子の投影面積と等しい面積を有する円の直径を指し、厚さは、平板粒子の２つの主平面間の距離を指す。粒子の直径は０．１μｍ以上が好ましく、０．２〜１０μｍがより好ましい。該平板粒子はＡｇＸ粒子の全投影面積の７５〜１００％、好ましくは９０〜１００％、より好ましくは９７〜１００％を占める。該平板粒子の厚さ分布の変動係数（分布の標準偏差／平均厚さ）は０〜０．３が好ましく、０〜０．２がより好ましく、０〜０．１が更に好ましい。
【００２３】
該平板粒子は少なくとも核形成→熟成→成長、の過程を経て製造される。最終的に得られる平板粒子の核は実質的に該核形成過程で形成される。ここで実質的にとは、数で、好ましくは７５〜１００％、より好ましくは９５〜１００％を指す。
核形成、熟成過程で該修飾ゼラチンを用いた場合は、それらの過程における反応溶液のｐＨは該修飾ゼラチンの等電点以上のｐＨが好ましく、（等電点ｐＨ＋０．２）〜ｐＨ１０がより好ましく、（等電点ｐＨ＋０．４）〜ｐＨ７が更に好ましい。核形成時に添加するＡｇＮＯ_３ の添加量は反応溶液１リットルあたり１ｇ以上が好ましく、１．８ｇ以上がより好ましく、３〜３０ｇが更に好ましい。核形成は反応溶液中へのＡｇ^＋ 液とＸ⁻ 液の同時混合添加法、または２〜１０００回の複数交互シングルジェット添加法で行う事がより好ましい。次に（１００）平板粒子から順に説明する。
【００２４】
Ａ−１．（１００）平板粒子
１．粒子構造
主平面が｛１００｝面である平板粒子を形状で分類すると、次の６つを挙げる事ができる。（１） 主平面の形状が直角平行四辺形で、１つの平板粒子内で隣接辺比率（長辺の長さ／短辺の長さ）が１〜１０、好ましくは１〜３の粒子、より好ましくは１〜２の粒子、（２） 該直角平行四辺形の４つの角の内、１個以上、好ましくは１〜３個が非等価的に欠落した粒子。即ち、〔（最大欠落部の面積／最小欠落部の面積）＝ａ_１ が２〜∞の粒子〕、（３） 該４つの角が等価的に欠落した粒子（該ａ_１ が２より小の粒子）、（４） 該欠落部の面積の５〜１００％、好ましくは２０〜１００％が（１１１）面である粒子、（５） 主平面を構成する４つの辺の内の少なくとも相対する２つの辺が外側に凸の曲線である粒子、（６） 該直角平行四辺形の４つの角の内の１つ以上、好ましくは１〜３個が直角平行四辺形状に欠落した粒子。
２．核形成
該（１００）平板粒子の核は次の方法で製造される。（１） 低保護コロイド性溶液中で、銀塩溶液とハロゲン塩溶液（以後、「Ｘ⁻ 塩液」と記す）を添加し、核形成する。Ｃｏａｇｕｌａｔｉｏｎ により結晶欠陥が形成されるとする考えがある。（２） 格子定数不整合による平板核形成法。例えば、ａ）ハロゲン組成ギャップ面を１つ以上、好ましくは１〜４つ、より好ましくは２〜３つ有する核を形成する。具体的には（ＡｇＸ_１ ｜ＡｇＸ_２ ）において、Ｘ_１ とＸ_２ のハロゲン組成をＣｌ⁻ 含率、またはＢｒ⁻ 含率、またはＩ⁻ 含率で１０〜１００モル％、好ましくは３０〜１００モル％、より好ましくは６０〜１００モル％だけ異なる。ここで（ＡｇＸ_１ ｜ＡｇＸ_２ ）はＡｇＸ_１ 核を形成した後、ＡｇＸ_２ 層を該核の表面上に積層させた態様を指す。より具体的には核形成時に添加するＸ⁻ 塩液のハロゲン組成を該ギャップ面の所で前記規定に従って不連続に変化させる事を指す。該ギャップはＡｇＸ_１ 核に、Ｘ_２ ⁻ 塩溶液を添加し、ハロゲン ｃｏｎｖｅｒｓｉｏｎ を生じさせる事によっても形成する事ができる。
【００２５】
該ギャップ面を２つ有する平板核は（ＡｇＸ_１ ｜ＡｇＸ_２ ｜ＡｇＸ_３ ）と記す事ができる。その他、ｂ）該格子不整による欠陥形成を促進する為に、該ギャップの隣接相間におけるイオウ、セレン、テルル、ＳＣＮ⁻ 、ＳｅＣＮ⁻ 、ＴｅＣＮ⁻ 、ＣＮ⁻ 、（Ａｇ^＋ 以外の金属イオン）、および該金属イオンの錯体（リガンドとしてはＸ⁻ リガンド、ＣＮ⁻ リガンド、イソシアノ、ニトロシル、チオニトロシル、アミン、ヒドロキシルを挙げることができる）の少なくとも１種以上の含有率差を好ましくは０．１〜１００モル％差、より好ましくは１〜１００モル％差、更に好ましくは１０〜１００モル％差にした態様を挙げることができる。Ａｇ^＋ 以外の金属イオンの代表例として周期律表の第８属金属イオン、Ｃｕ、Ｚｎ、Ｃｄ、Ｉｎ、Ｓｎ、Ａｕ、Ｈｇ、Ｐｂ、Ｃｒ、Ｍｎの各金属イオンを挙げることができる。
【００２６】
ｃ）その他、該不純物イオン含率ギャップのみによって、該欠陥を形成する態様を挙げる事ができる。これらの不純物イオンの具体的化合物例、ＡｇＸ相へのドープ方法の詳細に関してはＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ ，３０７巻，アイテム３０７１０５，１１月，１９８９年、米国特許５１６６０４５、同４９３３２７２、同５１６４２９２、同５１３２２０３、同４２６９９２７、同４８４７１９１、同４９３３２７２、同４９８１７８１、同５０２４９３１、特開平４−３０５６４４、同４−３２１０２４、同１−１８３６４７、同２−２０８５３、同１−２８５９４１、同３−１１８５３６の記載を参考にすることができる。
【００２７】
本発明では前記２−（２）、好ましくは２−（２）のａ）の核形成法を好ましく用いる事ができ、該ハロゲンコンバージョン法をより好ましく用いる事ができる。該平板粒子が形成されるのは平板粒子のエッジ方向に成長を促進する欠陥が存在する為である。該欠陥を本発明ではらせん転位欠陥と記す。１つの粒子中に該欠陥が多数形成されると、三次元方向への成長促進が起こり、生成する粒子は厚くなる。該欠陥形成確率をゼロから序々に上げていくと、まず辺比率１〜２の平板粒子が形成される事から、該粒子は〔１１０〕方向またはその−２５°〜＋２５°方向への成長促進ベクトルを有するらせん転位欠陥を１本有すると考えられる。該確率を更に上げていくと、該平板粒子の生成数が増し、更に上げると、低アスペクト比の粒子の混入比率が増す。これは該欠陥が１粒子あたり２本以上入り、厚さ方向に成長加速ベクトルを有するようになる為と考えられる。従って厚い粒子の混入率が許容される範囲内で該確率を高くすればよい。
【００２８】
該ギャップは（ＡｇＸ_１ ｜ＡｇＸ_２ ）組成で形成する方法の他、（ＡｇＸ_１ ｜ＡｇＸ_１２｜ＡｇＸ_２ ）核の形成によって形成してもよい。この場合ＡｇＸ_１２はＡｇ_１ Ｘ_１ とＡｇＸ_２ の間のハロゲン組成を有する中間層である。ＡｇＸ_１ とＡｇＸ_２ のハロゲン組成差を大きくすると、平板粒子核の数は増すが、厚い粒子の核数の比率も増す。中間層を入れる事により、平板粒子核の生成数は増すが、厚い粒子核の生成比率を抑制する効果がある。この場合、（ＡｇＸ_１ ｜ＡｇＸ_１２）および（ＡｇＸ_１２｜ＡｇＸ_２ ）のハロゲン組成ギャップ量は（ＡｇＸ_１ ｜ＡｇＸ_２ ）のギャップ量の１０〜９０％が好ましく、３０〜７０％がより好ましい。該中間層の数は１〜４、好ましくは１つである。該中間層は、前記のギャップ面を２つ以上有する態様に対しても、そのギャップ面の１つ以上に対して設ける事ができる。
【００２９】
３．熟成
核形成で生成した核の内、この熟成過程で非平板粒子核を個数で好ましくは３０〜１００％、より好ましくは６０〜１００％を消失させ、平板粒子の投影面積比率を高める。具体的には反応溶液のＡｇＸ溶解度を１．１倍以上、好ましくは１．５〜３０倍に高めて熟成する。該溶解度を高める方法として次の方法を挙げる事ができる。（１） 温度を５℃以上、好ましくは１０〜６０℃だけ高くする。（２） Ｘ⁻ 塩または銀塩を加える。（３） ＡｇＸ溶剤を加える。（４） 前記（１） 〜（３） の２つ以上の併用方法。反応溶液中の（Ｃｌ⁻ 濃度／Ｘ⁻ 濃度）が０．９〜１．０の場合、該昇温でまず３０％以上の該核を消失させた後、Ｃｌ⁻ 塩を加え、ＡｇＸ溶解度を１．１倍以上、好ましくは１．３〜１０倍に高めて、残りの該核の８０〜１００％、好ましくは９７〜１００％を消失させる事がより好ましい。
消失後、該過剰Ｃｌ⁻ 濃度は、ＡｇＮＯ_３ 液を添加し、低下させる事もできるし、従来公知の乳剤脱塩法で脱塩し、低下させる事もできる。ＡｇＮＯ_３ 液の添加速度は最適の添加速度を選ぶ事ができ、新核発生しない速度で添加する事が好ましい。
【００３０】
該ハロゲン組成ギャップ面を形成した核を熟成し、非平板粒子核を消滅させる場合、その時成長する平板粒子に異種ハロゲンイオンが蓄積する。この時、平板粒子に更にらせん転位等の欠陥が組み込まれ、主平面と垂直な方向の成長ベクトル成分を有する成長促進欠陥が組込まれる。その為に、成長と共に平板粒子は更に厚くなる。これを防止する為には、異種ハロゲンイオンをホストハロゲンイオンで希釈すればよい。具体例を挙げると、（内核｜外核）が（ＡｇＸ_１ ｜ＡｇＸ_２ ）核の場合、熟成時に放出される異種イオンＸ_２ を希釈する為に、Ａｇ^＋ とＸ_１ ⁻ を添加しながら熟成する方法、核の構造を（ＡｇＸ_１ ｜ＡｇＸ_２ ｜ＡｇＸ_１ ）とする方法、粒子直径０．０１〜０．１５μｍのＸ_１ 組成比率の高い微粒子を添加する方法、その２つ以上の併用法、を挙げることができる。該希釈により、非平板粒子核を消滅させる時に新たに形成されるらせん転位欠陥数が、既に存在する欠陥数の０〜０．３が好ましく、０〜０．２がより好ましい。
【００３１】
Ａ−２．（１１１）平板粒子
１．粒子構造
（１１１）平板粒子の主平面の形状で分類すると、次の２つを挙げる事ができる。（１） 主平面の周囲形状が実質的に六角形である六角平板粒子。ここで実質的にとは該六角形の最大隣接辺比率〔１つの六角形内の（最長辺の長さ／最短辺の長さ）〕が１〜２、好ましくは１〜１．５、より好ましくは１〜１．２である態様を指す。（２） 主平面の周囲形状が実質的に三角形である三角平板粒子。ここで実質的にとは該隣接辺比率が２より大である態様を指す。（３） 前記（１） 、（２） の粒子の角が丸くなった態様。該周囲辺の直線部の比率（ｂ_１ ）が０〜０．５の円形平板粒子と、０．５＜ｂ_１ ≦１．０の粒子を挙げる事ができる。ｂ_１ 値は該周囲辺の直線部を延長し、形成される交点間の長さに対する該辺の直線部の長さの割合を指す。（４） 前記（１） 〜（３） の粒子で〔エッジ面の｛１１１｝面の面積／エッジ面の総面積〕が０〜１．０の粒子と、〔エッジ面の｛１００｝面の面積／エッジ面の総面積〕が０〜１．０の粒子。〔エッジ面の｛１１１｝の面積／エッジ面の｛１００｝面の面積〕が０．０１〜１００の粒子。
【００３２】
前記６個の辺を有する六角平板粒子および三角平板粒子の態様において、１つおきの３つの辺の（最長辺の辺長／最短辺の辺長）＝ｂ_２ は１〜１．３が好ましく、１〜１．２がより好ましく、１〜１．１が最も好ましい。該粒子の投影面積の合計が、全ＡｇＸ粒子の投影面積の合計の８０％以上、好ましくは９０％以上、より好ましくは９７〜１００％を占める態様が好ましい。
主平面に平行な双晶面の枚数は２〜４枚、好ましくは２〜３枚、より好ましくは２枚である。２枚の粒子は通常、該六角平板粒子で３枚の粒子は該三角平板粒子であるが、２枚で三角平板粒子である態様も存在する。特に０．１μｍ以下の薄い平板粒子を低過飽和度下で成長させた場合に出現する。エッジ面には凹入角部と凸入角部が存在するが、凹入角部の方が原子結合手数が多い為により速く成長する。薄い平板粒子では（厚さ／双晶面間隔）が小さい為、（凹入角部の面積≠凸入角部の面積）である事が多い。
【００３３】
該粒子を低過飽和成長させた場合、（凹入角面の面積＞凸入角面の面積）の辺がより速く成長する為と考えられる。平行双晶面を３枚有する粒子では、エッジ部の成長速度が（凹入角を２つ有するエッジ部＞凹入角を１つ有するエッジ部）となる為と考えられる。凹入角部を２つ有するエッジ部は、（成長活性点数／単位面積）がより多く、かつ、（凹入角の面積＞凸入角の面積）の関係が成り立つ為である。
（平板粒子の厚さ／双晶面の間隔）または（平板粒子の厚さ／最外双晶面間の間隔）は１．１以上、好ましくは１．５〜１００、より好ましくは２〜５０である。最外双晶面とは、主平面に最も近い双晶面を指す。本発明では前記六角平板粒子またはその角が丸くなった粒子（０．５＜ｂ_１ ＜１．０）が好ましく、隣接辺比率が１〜１．５がより好ましく、１〜１．２が更に好ましい。該粒子を以後、「正六角平板粒子」と呼ぶ。
【００３４】
２．核形成
核形成時の温度は６０℃以下が好ましく、１０〜５０℃がより好ましい。分散媒濃度は０．０１〜５重量％が好ましく、０．０１〜１重量％がより好ましく、０．０３〜０．６重量％が更に好ましい。Ｘ⁻ 塩濃度は１０^−０．８〜１０^−３モル／リットルが好ましく、１０^−１．２〜１０^−２．７モル／リットルがより好ましく、１０^−１．６〜１０^−２．７モル／リットルが更に好ましい。添加するＡｇ^＋ 液および／またはＸ⁻ 液が分散媒を含む態様が好ましく、該濃度が０．０１〜１重量％が好ましく、０．０３〜０．６重量％がより好ましい。分散媒の分子量は３０００〜２０万が好ましく、３０００〜１０万がより好ましい。反応溶液のｐＨは１〜１１が好ましく、２〜６がより好ましい。分散媒はゼラチンが好ましく、アルカリ処理ゼラチンがより好ましく、後述の修飾ゼラチンがより好ましい。
次の熟成過程での熟成をより迅速に行なわせ、かつ、平板粒子比率をより高める為には、ＡｇＸ溶解度の低い条件で微小核を形成する事が好ましい。即ち低Ｘ⁻ 濃度、低温が好ましい。Ｘ⁻ 濃度の低下に伴う双晶面形成確率の低下は分散媒濃度を低下させる事によって補えばよい。また、ｐＨを下げる程、通常、分散媒のＡｇＸ溶解度が低下するので好ましい。
核形成時に添加する銀塩量の３０％以上、好ましくは６０〜１００％、より好ましくは８０〜１００％はＸ⁻ 塩液と同時混合添加する事が好ましい。
【００３５】
３．熟成
核形成で生成した核の内、この熟成過程で非平板粒子核を個数で好ましくは７５〜１００％、より好ましくは９０〜１００％、更に好ましくは１００％を消失させ、平板粒子の投影面積比率を高める。具体的には反応溶液の溶解度を１．１倍以上、好ましくは１．５〜３０倍に高めて熟成する。該溶解度を高める方法としては前記Ａ−１の３項記載の方法を挙げる事ができる。該熟成時の分散媒の濃度は低い程、またｐＨは低い程、該熟成はより迅速に進行する。これは分散媒のＡｇＸ粒子に対する吸着力が弱くなり、平板粒子の成長疎外因子が除かれる事、および、非平板粒子の溶解が促進される為と解される。熟成時の分散媒濃度、分散媒の分子量、反応溶液のｐＨ、分散媒の種類に関しては前記２の項の記載を参考にする事ができる。Ｘ⁻ 塩濃度は１０^−０．８〜１０^−２．５モル／リットルが好ましく、１０^−１．２〜１０^−２モル／リットルがより好ましい。
【００３６】
Ｂ．平板粒子の成長条件
本発明では該成長過程の分散媒溶液中の分散媒の３０〜１００重量％、好ましくは６０〜１００重量％、より好ましくは７５〜９８重量％、最も好ましくは８０〜９６重量％が（化学修飾された−ＮＨ_２ 基数の％とメチオニン含率の関係が図１のａ_１ 、好ましくはａ_２ 、より好ましくはａ_３ の領域にあるゼラチン）である。該態様を実現する為の方法として次の方法を挙げる事ができる。
【００３７】
（１） 核形成、熟成を該修飾ゼラチン以外の分散媒（以後、「非修飾媒」と記す）を用いて行い、成長前に該分散媒の１０〜９９．７重量％を除去し、新たに該修飾ゼラチンを添加する方法。（２） 核形成を非修飾媒を用いて行ない、核形成後に該分散媒の１０〜９９．５重量％を除去し、新たに該修飾ゼラチンを添加する方法。（３） 核形成を非修飾媒の低濃度下で行ない、核形成後に該修飾ゼラチンを添加する方法。（４） 核形成、熟成を非修飾媒の低濃度下で行ない、熟成後に該修飾ゼラチンを添加する方法。（５） 核形成、熟成を該修飾ゼラチンの該濃度下で行う方法。核形成後、または熟成後に更に該修飾ゼラチンを添加する事もできる。（６） 核形成後まで、または熟成後までを非修飾ゼラチンの存在下で行ない、次に後述の修飾剤を用いて該ゼラチンを修飾し、該修飾ゼラチンの比率を高める方法。（７） 核形成後まで、または熟成後までを非修飾ゼラチンの存在下で行ない、次に非修飾ゼラチンを添加し、均一化混合した後に後述の修飾剤を用いて該ゼラチンを修飾し、該修飾ゼラチンの比率を高める方法。
【００３８】
該分散媒の除去方法としては次の方法を挙げる事ができる。１）ＡｇＸ乳剤を遠心分離し、上澄み液を除去する方法。２）限外濾過膜を用いて、限外濾過法で除去する方法。３）凝集沈降剤を加え、沈降水洗する方法、または遠心分離法と併用する方法。
該分散媒の除去率は３０〜９９．５重量％が好ましく、６０〜９９％が更に好ましく、９０〜９９％が最も好ましい。
前記（１） 〜（４） 、（６） 、（７） の方法をより好ましく用いる事ができる。（３） 、（４） の低濃度は、０．０１〜１重量％、好ましくは０．０３〜０．６重量％、より好ましくは０．０３〜０．３重量％を指す。また、後で添加する修飾ゼラチンの添加量は、本発明の態様が達成されるに必要な量である。
【００３９】
平板粒子を厚くせず、かつ、サイズ分布を広げずに成長させる為には分散媒のＡｇＸ粒子に対する吸着性を精密に制御する必要がある。ゼラチン水溶液にＨ_２ Ｏ_２ を添加し、ゼラチンを酸化した場合、Ｈ_２ Ｏ_２ の添加量と共に、ゼラチンの（メチオニンスルホキシド基数／メチオニン基数）＝Ｃ_１ が増加する。Ｃ_１ の増加と共にゼラチンのＡｇＸ粒子への吸着力は低下する。該Ｃ_１ 値の異なる種々のゼラチンを用い、その水溶液中で（１１１）平板粒子を同一条件で成長させた場合、得られる平板粒子はＣ_１ 値の増加と共により薄くなるが、同時によりサイズ分布は広がる。この現象は次のように理解する事ができる。
【００４０】
該酸化により、リジン基、アスパラギン酸基、グルタミン酸基は全く変化を受けていない為、この変化はＣ_１ 値の変化に帰せられる。即ち、メチオニン基の強い吸着がなくなる為に平板粒子のエッジ面の成長律速は、メチオニン基の脱着律速からエッジ面の反応律速へと変る。（１１１）平板粒子の成長活性場所はエッジの凹入角部である為、１つの平板粒子で凹入角部上に成長核が形成される確率は、平板粒子の周囲のエッジ長に比例する。該エッジ長（２πｄ）は直径（ｄ）に比例する為、成長核形成確率はｄに比例する。成長核形成過程が成長律速の場合、成長速度は（大粒子＞小粒子）となり、成長と共にサイズ分布は広がる。
【００４１】
しかし、該酸化ゼラチンにメチオニンを１００（μｍｏｌ ／ｇゼラチン）だけ添加して平板粒子を成長させても該薄平板粒子が形成される。従ってゼラチン中のメチオニン基のみが単独で強い吸着力を保持しているのではない。ゼラチンのアミノ基を無水フタル酸でフタル化し、種々のフタル化率のゼラチンを調製する。次に、該分散媒中で同一の種晶平板粒子を同一条件で成長させた場合、フタル化率の増加と共に、生成する平板粒子は薄くなるが、サイズ分布はあまり広がらない。従って、薄くてサイズ分布の揃った平板粒子を調製する為には、ゼラチンのメチオニン基の含率とアミノ基の含率の最適の組合せを選ぶ事が必要である。この最適値の選択は本発明により初めてなされた。１−フェニル−５−メルカプトテトラゾールはＡｇＸ粒子に強く吸着するが、メルカプト基単独、またはテトラゾール基単独ではそれ程強い吸着を示さない。前記現象はこれと同様に考える事ができる。即ち、ゼラチンのＡｇＸ粒子に対する強い吸着はゼラチン分子中のメチオニン基と−ＮＨ_２ 基の協奏効果により生じていると考えられる。 また、前記酸化ゼラチンで成長させた場合、六角形の形状の歪んだ平板粒子が形成されるが、図１のａ_１ の領域、好ましくはａ_２ の領域のゼラチンを用いた場合は、正六角平板粒子が形成される。
【００４２】
分散媒のＡｇＸ粒子に対する吸着力を制御するもう一つの大きな因子は温度である。同じ分散媒であっても、温度を低くする程、吸着基が脱着する頻度が減少し、粒子成長はより脱着律速成長となる。この場合、平板粒子のすべての表面はより等速成長に近づく。従って温度を高くする程、該脱着律速が除去され、エッジの選択成長性が高められ、より高アスペクト比の平板粒子が得られる。同じ平板粒子を種々の分散媒を用いて３０〜８０℃の種々の温度で成長させた場合、得られる平板粒子の該アスペクト比変化は、メチオニン含率が高く、かつ、自由アミノ基含率の高いゼラチンの方が、大きくなる。本発明の態様では、該温度変化が小さく、広い温度範囲において高アスペクト比で単分散の平板粒子が得られる。また、ＡｇＸ粒子への適度な吸着力が保たれる為にかぶりの発生が抑えられ、（感度／かぶり）比の高い粒子が得られる。成長温度は３０℃以上が好ましく、４０〜９０℃がより好ましい。最も好ましい温度を選んで用いる事ができる。
分散媒のＡｇＸ粒子に対する吸着力を制御するもう１つの大きな因子はｐＨである。メチオニン含率がゼロの酸化処理ゼラチンを用い、種々のｐＨの分散媒溶液を調製する。同じ（１１１）平板種晶をそれぞれの溶液に入れ、成長させた場合、ｐＨの上昇と共に厚い平板粒子の混入比率が増す。ｐＨ８以上、特にｐＨ９以上で顕著になる。この時、メチオニンスルホキシドは変化しない事から、メチオニンだけが厚板粒子の生成原因ではない事を示している。これに対し、本発明の修飾ゼラチンを用いた場合は、該ｐＨ依存性が小さく、ｐＨ９〜１０においても厚板粒子は混入しない。即ち、成長ｐＨが６〜１１、好ましくは６〜１０でより利点が大きくなる。
一方、（１００）平板粒子の場合は、熟成、成長条件をより高ｐＨにする程、薄い平板粒子が得られる。それらの関係と理由は表１にまとめた。ここでＧｅｌ．はゼラチンを指す。
【００４３】
【表１】

【００４４】
これらの平板粒子の成長は目的に応じて最も好ましい過飽和度を選んで成長させる事が好ましい。臨界過飽和度を１００、溶質の添加なしの時の過飽和度を０とした場合、５〜９０が好ましく、１０〜８０がより好ましい。ここで臨界過飽和度とは、ＡｇＮＯ_３ 水溶液とＸ⁻ 塩水溶液を同時混合添加した場合、それ以上の添加速度で添加すると新核が発生する状態の時の過飽和度を指す。過飽和度を高くすると、得られる平板粒子はより単分散化するが、厚さ方向へも成長し、低アスペクト比化する。過飽和度を低くするとより高アスペクト比化するが、サイズ分布が広くなる。
成長時の該分散媒の濃度は０．１〜７重量％が好ましく、０．３〜３重量％がより好ましい。分子量は３０００〜２０万、好ましくは６０００〜１２万である。溶液のｐＨは該修飾ゼラチンの等電点以上のｐＨが好ましく、（等電点ｐＨ＋０．２）〜ｐＨ１１がより好ましく、（等電点ｐＨ＋０．４）〜ｐＨ１０が更に好ましい。同一条件で平板粒子を成長させた時、ｐＨは低下する程、ゼラチン濃度は低下する程、該分子量は低下する程、生成する平板粒子は高アスペクト比化する。目的に応じて最も好ましい組合せを選んで用いる事ができる。
【００４５】
（１１１）平板粒子の熟成時、成長時の反応溶液中のＸ⁻ の濃度は八面体粒子生成領域が好ましい。ここで八面体粒子生成領域とは、該Ｘ⁻ 濃度条件に保ちながらＡｇ^＋ とＸ⁻ を同時混合添加し、ＡｇＸ粒子を形成した場合、粒子表面の７０〜１００％、好ましくは９０〜１００％が｛１１１｝面の粒子が生成する濃度範囲を指す。通常、該Ｘ⁻ 濃度は１０^−０．５〜１０^−２．５モル／リットルが好ましく、１０^−１〜１０^−２モル／リットルがより好ましい。
該特徴は（１１１）平板粒子の他、（１００）平板粒子においても見られる。従って前記（１００）平板粒子に対しても好ましく用いる事ができる。（１００）平板粒子の核形成、熟成、成長時の反応溶液中のＸ⁻ 濃度は立方体粒子生成領域が好ましい。ここで立方体粒子生成領域とは、該Ｘ⁻ 濃度条件に保ちながらＡｇ^＋ とＸ⁻ を同時混合添加し、ＡｇＸ粒子を形成した場合、粒子表面の７０〜１００％、好ましくは９０〜１００％が｛１００｝面の粒子が生成する濃度範囲を指す。通常、該Ｘ⁻ 、およびＡｇ^＋ 濃度は１０^−１．５モル／リットル以下が好ましく、１０^−２モル／リットル以下がより好ましい。
前記平板粒子のその他の詳細に関しては、前記「従来の技術」の項に記載した文献の記載および特開平３−２８８１４３号、同３−２１２６３９号、同３−１１６１３３号、同２−３０１７４２号、同２−３４号、同６−５９３６０号、特願平６−４７９９１号、同５−２４８２１８号、同５−２６４０５９号、同５−９６２５０号、後述の文献の記載を参考にする事ができる。
【００４６】
Ｃ．修飾ゼラチン
ゼラチン中の−ＮＨ_２ 基としてはゼラチン分子の末端基のアミノ基、リジン基、ヒドロキシリジン基、ヒスチジン基、アルギニン基のアミノ基の他、アルギニン基がオルニチン基に変換されていれば、そのアミノ基を挙げる事ができる。更にアデニン、グアニン基等の不純物基も挙げる事ができる。−ＮＨ_２ 基の化学修飾とはゼラチンに反応試薬を添加し、該アミノ基と反応させ、共有結合を形成または脱アミノ化する事である。即ち、一級アミノ基（−ＮＨ_２ ）を２級アミノ基（−ＮＨ−）、３級アミノ基、または脱アミノ化体に変化させる事を指す。
【００４７】
具体的には例えば酸無水物（マレイン酸無水物、ｏ−フタル酸無水物、コハク酸無水物、ｉｓａｔｏｉｃ ａｎｈｙｄｒｉｄｅ 、安息香酸無水物等）、酸ハロゲン化物（Ｒ−ＣＯＸ、Ｒ−ＳＯ_２ Ｘ、Ｒ−Ｏ−ＣＯＸ、Ｐｈｅｎｙｌ−ＣＯＣｌ等）、アルデヒド基を有する化合物（Ｒ−ＣＨＯ等）、エポキシ基を有する化合物、脱アミノ基剤（ＨＮＯ_２ 、ｄｅａｍｉｎａｓｅ 等）、活性エステル化合物（スルホン酸エステル、ｐ−ニトロフェニルアセテート、イソプロペニルアセテート、メチルｏ−クロロベンゾエート、ｐ−ニトロフェニルベンゾエート等）、イソシアネート化合物 （Ａｒｙｌ ｉｓｏｃｙａｎａｔｅ 等） 、活性ハロゲン化合物、例えば〔Ａｒｙｌ ｈａｌｉｄｅ （ｂｅｎｚｙｌ ｂｒｏｍｉｄｅ， ｂｉｐｈｅｎｙｌ−ｈａｌｏｍｅｔｈａｎｅｓ， ｂｅｎｚｏｙｌ ｈａｌｏｍｅｔｈａｎｅ， ｐｈｅｎｙｌ ｂｅｎｚｏｙｌｈａｌｏ−ｍｅｔｈａｎｅ， １−Ｆｌｕｏｒｏ−２，４−ｄｉｎｉｔｒｏ−ｂｅｎｚｅｎｅ）， β−ｋｅｔｏｈａｌｉｄｅ， α−ｈａｌｏａｌｉｐｈａｔｉｃ ａｃｉｄ， β−ｈａｌｏｎｉｔｒｉｌｅ， （ｓ−ｔｒｉａｚｉｎｅ， ｐｙｒｉｍｉｄｉｎｅ， ｐｙｒｉｄａｚｉｎｅ， ｐｙｒａｚｉｎｅ， ｐｙｒｉｄａｚｏｎｅ， ｑｕｉｎｏｘａｌｉｎｅ， ｑｕｉｎａｚｏｌｉｎｅ， ｐｈｔｈａｌａｚｉｎｅ， ｂｅｎｚｏｘａｚｏｌｅ， ｂｅｎｚｏｔｈｉａｚｏｌｅ， ｂｅｎｚｏｉｍｉｄａｚｏｌｅ） のクロル誘導体〕、
カルバモイル化剤（ｃｙａｎａｔｅ， ｎｉｔｒｏｕｒｅａ 等） 、アクリル型活性２重結合基を有する化合物（ｍａｌｅｉｍｉｄｅ， ａｃｒｙｌａｍｉｎｅ， ａｃｒｙｌａｍｉｄｅ， ａｃｒｙｌｏｎｉｔｒｉｌｅ， ｍｅｔｈｙｌｍｅｔｈａａｃｒｙｌａｔｅ， ｖｉｎｙｌ ｓｕｌｐｈｏｎｅ， ｖｉｎｙｌｓｕｌｐｈｏｎａｔｅ ｅｓｔｅｒ， ｓｕｌｐｈｏｎａｍｉｄｅ， ｓｔｙｒｅｎｅ ａｎｄ ｖｉｎｙｌｐｙｒｉｄｉｎｅ， ａｌｌｙｌａｍｉｎｅ， ｂｕｔａｄｉｅｎｅ， ｉｓｏｐｒｅｎｅ， ｃｈｌｏｒｏｐｒｅｎｅ等） 、ｓｕｌｔｏｎｅ 類（ｂｕｔａｎｅ ｓｕｌｔｏｎｅ， ｐｒｏｐａｎｅ ｓｕｌｔｏｎｅ）， Ｇｕａｎｉｄｉｎｅ化剤（ｏ−ｍｅｔｈｙｌｉｓｏｕｒｅａ等） 、ｃａｒｂｏｘｙｌａｚｉｄｅ 等を加え、反応させる事により達成する事ができる。
【００４８】
この場合、ゼラチンの−ＯＨ基や−ＣＯＯＨ基とも反応し、共有結合を形成する試薬よりは主としてゼラチンの−ＮＨ_２ 基と反応する試薬がより好ましい。主としては、６０％以上、好ましくは８０〜１００％、より好ましくは９５〜１００％を指す。更には該反応生成物が、（エーテル基やケトン基の酸素がカルコゲン原子に置き代った基、例えば−Ｓ−、チオン基）を実質的に含まない態様がより好ましい。ここで実質的に含まないとは該化学修飾された基数の好ましくは１０％以下、より好ましくは０〜３％を指す。従って前記の内、酸無水物、ｓｕｌｔｏｎｅ 類、活性２重結合基を有する化合物、カルバモイル化剤、活性ハロゲン化合物、イソシアネート化合物、活性エステル化合物、アルデヒドを有する化合物、脱アミノ基剤がより好ましい。該化学修飾により、ゼラチン分子間で架橋が実質的にできない態様がより好ましい。ここで実質的にできないとは、該化学修飾された基の１０％以下が好ましく、０〜３％が更に好ましい。
【００４９】
該化学修飾剤およびゼラチンの該化学修飾法のその他の詳細に関しては後述の文献、特開平４−２２６４４９、特開昭５０−３３２９号、米国特許第２５２５７５３号、同２６１４９２８号、同２６１４９２９号、同２７６３６３９号、同２５９４２９３号、同３１３２９４５号、安孫子義弘編，にかわとゼラチン，第ＩＩ章，日本にかわ・ゼラチン工業組合（１９８７年）、Ｗａｒｄら編， Ｔｈｅ Ｓｃｉｅｎｃｅ ａｎｄ Ｔｅｃｈｎｏｌｏｇｙ ｏｆ Ｇｅｌａｔｉｎ， 第７章，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ（１９７７）の記載を参考にする事ができる。
該修飾ゼラチンの−ＮＨ_２ 基の化学修飾％は次のようにして求める事ができる。該修飾を行なっていないゼラチンと該修飾を行なったゼラチンを準備し、両者の−ＮＨ_２ 基数をｅ_１ 、ｅ_２ として求める。化学修飾％は１００×（ｅ_１ −ｅ_２ ）／ｅ_１ より求める事ができる。該ｅ_１ とｅ_２ の求め方は、−ＮＨ_２ 基に基づく赤外吸収強度や、該プロトンのＮＭＲ信号強度、呈色反応および蛍光反応を利用する方法を挙げる事ができ、詳細は分析化学便覧、有機編−２、丸善（１９９１）の記載を参考にする事ができる。その他、ゼラチンの滴定曲線の変化、ｆｏｒｍｏｌ滴定法等の定量法を挙げる事ができ、詳細は Ｔｈｅ Ｓｃｉｅｎｃｅ ａｎｄ Ｔｅｃｈｎｏｌｏｇｙ ｏｆ Ｇｅｌａｔｉｎ， 第１５章，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ（１９７７年）の記載を参考にする事ができる。
【００５０】
その他、グルタルアルデヒドとＢｒｉｔｔｏｎ−Ｒｏｂｉｎｓｏｎ 高ｐＨ緩衝液の混合物を指定濃度のゼラチン溶液に添加し、発色させ、４５０ｎｍ近傍の分光吸収強度を測定し、比色定量する事により求める方法〔Ｐｈｏｔｏｇｒａｐｈｉｃ Ｇｅｌａｔｉｎ ＩＩ， ｐ． ２９７〜３１５，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ（１９７６）の記載を参考にする事ができる〕を挙げる事ができる。
該ゼラチンのメチオニン含率は、ゼラチンをアルカリ加水分解法で完全にアミノ酸に分解し、アミノ酸分析計で分析し、グリシン量に対するメチオニン量を求める事により求める事ができる。詳細は特願平６−１０２４８５の記載を参考にする事ができる。該ゼラチンのメチオニン含率は、ゼラチン水溶液に酸化剤を添加し、メチオニンの−Ｓ−基をスルフォキシド、スルフォネート、スルフォンの１つ以上に酸化する事により調節する事ができる。好ましくはスルフォキシドに酸化する。即ち、本発明ではメチオニンの該酸化体はメチオニンと見なされない。該酸化のレベルは主として添加する酸化剤の種類とその添加量により調節する事ができる。該水溶液の温度は１０〜７０℃が好ましく、２５〜５０℃がより好ましい。ｐＨは２〜９が好ましく、３〜７がより好ましい。通常、温度、ｐＨを一定に調節したゼラチン水溶液中に酸化剤を添加し、均一混合化する。次に、容器にフタをし、恒温、静置し、好ましくは１５分間〜３日間、より好ましくは１〜２４時間、経時する。酸化剤に関しては特願平６−１０２４８５の記載を参考にする事ができる。通常はＨ_２ Ｏ_２ を好ましく用いる事ができる。
【００５１】
該酸化により、ゼラチンの吸光係数（２００〜５００ｎｍ波長域）が低下する。従って、種々の酸化レベルの試薬を作り、該吸光係数とメチオニン含率の関係を求めておけば、それ以後は、吸光係数の測定により、該ゼラチンのメチオニン含率を簡便に求める事ができる。標準的なゼラチンのアミノ酸組成は、Ｔｈｅ Ｔｈｅｏｒｙ ｏｆ Ｔｈｅ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓ， 第２章，Ｍａｃｍｉｌａｎ（１９７７年）に記されており、メチオニンは１分子中に８分子含まれている。ゼラチンの分子量を９６，０００とすると、メチオニン含率は８３μｍｏｌ／ｇ であり、従来のゼラチンのメチオニン含率は約８０μｍｏｌ／ｇ 近傍と見なす事ができる。図１のａ_１ 、ａ_２ 領域においてメチオニン含率は６０μｍｏｌ／ｇ 以下が好ましく、５０μｍｏｌ／ｇ 以下がより好ましく、４０μｍｏｌ／ｇ 以下が更に好ましく、３６μｍｏｌ／ｇ 以下が最も好ましい。図１のａ_３ 領域においてはメチオニン含率は４０μｍｏｌ／ｇ 以下が好ましい。
【００５２】
Ｄ．ＰＡＯ重合体
ポリアルキレンオキサイド重合物（以後、「ＰＡＯ重合体」と記す）を核形成前〜成長終了の５分前、好ましくは１０分前までの間に、より好ましくは核形成後〜成長開始直前までの間に添加する事が好ましい。前記平板粒子形成、更にはＢｒ⁻ 含率が５０〜１００モル％の（１１１）平板粒子形成に対して、より好ましく添加する事ができる。該ＰＡＯ重合体の詳細に関しては欧州特許０５１４７４２Ａ１、特願平５−１１８４１８、同５−１９１８１４、同５−２６３１２８に記載の化合物が好ましく、特に特願平５−１９１８１４、同５−２６３１２８記載の態様を好ましく用いる事ができる。下記第１〜第６態様のＰＡＯ重合体の分子量は５００〜１０^６ が好ましく、１０^３ 〜１０^５ がより好ましい。下記第１、第２態様のＰＡＯ重合体の該添加量は０．００１〜２０ｇ／リットルが好ましく、０．００３〜１０ｇ／リットルがより好ましい。下記第３〜第６態様の各重合体の該添加量は０．０１〜２０ｇ／リットルが好ましく、０．０３〜１０ｇ／リットルがより好ましい。下記第３〜第６態様の各重合体の該添加量は０．０１〜２０ｇ／リットルが好ましく、０．０３〜１０ｇ／リットルがより好ましい。粒子成長時のｐＨは５〜１１が好ましく、５〜９．５がより好ましい。
【００５３】
ＡｇＸ粒子への有機エーテル化合物の吸着力の強さの順は、一般的傾向として−Ｏ−＜−Ｓ−＜−Ｓｅ−＜−Ｔｅ−、である。酸素エーテル基のＡｇＸ粒子への吸着力は、チオエーテル基のそれに比べて弱い為、ＡｇＸ粒子の成長を強く抑制する事がない。また、そのＡｇＸ粒子への吸着はファンデアワールスカに基づく為にＡｇＸ粒子の｛１１１｝面よりも｛１００｝面の方により選択的に吸着する。それは｛１１１｝面に比べて｛１００｝面の方がＡｇ^＋ とＸ⁻ を有する為に誘起双極子モーメントが大きい為である。（１１１）平板粒子で｛１００｝面が現れ易いのはエッジ面であるからＰＡＯは主平面よりもエッジ面に適度の吸着力で吸着する。そしてエッジ面の成長律速をＰＡＯの脱着律速に変える。単位面積あたりのＰＡＯの吸着分子数が等しければ、大粒子も小粒子も、各単位面積の成長速度は同じである。従って、大粒子も小粒子も、エッジ面が等速で成長し、成長と共に直径分布の変動係数は小さくなる。
【００５４】
ＰＡＯ重合体の該吸着の晶癖依存性は、次の方法で求める事ができる。等表面積の単分散立方体粒子乳剤と八面体粒子乳剤を準備し、各々にＰＡＯ化合物を添加し、吸着平衡に達せしめた後、遠心分離し、上澄み液の分析をする。例えば該ＰＡＯの曇点以上の温度の場合はその分光透過強度の比較により求める事ができる。その他、クロマトグラフィー法でＰＡＯ成分を分離し分析する方法（例えばゲル濾過クロマトグラフィー法）を挙げる事ができる。その他、誘電損失法で該立方体と八面体粒子のイオン電導度を測定し、該吸着によるイオン伝導度変化量を求める事によっても比較する事ができる。
【００５５】
従来のゼラチンのＡｇＸ粒子への吸着は通常、｛１１１｝面よりも｛１００｝面に強く起こる。それは主として粒子表面のＡｇ^＋ との相互作用に基づいて吸着する為である。この場合、ＰＡＯ重合体の｛１００｝面への吸着は疎外される。しかし、該修飾ゼラチンの場合、ＡｇＸ粒子への吸着が弱い為、ＰＡＯ重合体の｛１００｝面への選択的吸着が可能となり、前記態様の好ましい成長特性が得られる。ＰＡＯ重合体は該吸着でＡｇＢｒ粒子のイオン伝導度を増加させる事から、｛１００｝面のＢｒ⁻ との相互作用が大きいと考えられる。
また、該ＰＡＯ重合体とＸ⁻ との水溶液中の相互作用は次の方法で求める事ができる。該ＰＡＯを含む水溶液中と、含まない水溶液中にそれぞれＸ⁻ 選択電極を入れ、Ｘ⁻ 塩の添加量と該電極電位（対標準電極）との関係を求め、比較すればよい。ＰＡＯ重合体に取り込まれたＸ⁻ 量分だけ該電位変化は小さくなる。
【００５６】
該ＰＡＯ重合体の第１態様はＨＰＡＯであり、前記一般式（１）−ａ）または（１）−ｂ）で表される。ＨＰＥＯＵの分子量は分子全体の分子量の９６．１〜１００％、好ましくは９７〜１００％を占める態様（ＨＰ１）と４〜９６％を占める態様（ＨＰ２）を挙げる事ができる。
（１）式において、Ｒ^０ はＨ、または少なくとも１つの極性基を有する炭素数１〜１０の炭化水素（例えば−ＣＨ_２ＯＨ、−Ｃ_２Ｈ_５ＯＨ 、−ＣＨ_２−Ｏ−ＣＨ_３） で、好ましくはＨである。Ｒは炭素数３以上、１０以下のアルキレン基を表し、具体例として −ＣＨ（ＣＨ_３）ＣＨ_２− 、−ＣＨ_２ＣＨ（ＣＨ_３）− 、−ＣＨ_２ＣＨ_２ＣＨ_２− 、−（ＣＨ_２）_４−、−（ＣＨ_２）_５−、−ＣＨ_２ＣＨ（Ｃ_６Ｈ_５）− を挙げる事ができ、 −ＣＨ（ＣＨ_３）ＣＨ_２− 、−ＣＨ_２ＣＨ（ＣＨ_３）−が特に好ましい。
ｎ、ｍは繰返し単位の平均数を表し、前記分子量規定を満たす４以上好ましくは６〜１０，０００、より好ましくは１０〜２０００の値である。
【００５７】
但し、重合時の環状エーテルの開環位置の選択性が十分ではないので、前記（１）−ｄ）式で例えば−〔ＣＨ_２ＣＨ（ＣＨ_３）Ｏ 〕−と−〔ＣＨ（ＣＨ_３）ＣＨ_２Ｏ 〕−が混入する事がある。
該ＰＡＯ重合体の第２態様はＰＥＯＤであり、一般式で表すと、前記（２） 式の（ａ）〜（ｆ）で表される。ここでＬＰＵはＨＯ−ＨＰＥＯＵ−基およびＨＯ−ＬＰＡＯＵ−基以外の親油性基を指し、置換または無置換のアルキル基、アルケニル基、アリール基、ヘテロ環基、アルコキシ基、アリーロキシ基、アシル基、アシルアミノ基、アルキルチオ基、アリールチオ基、アルコキシカルボニル基、アリーロキシカルボニル基、アリサイクリック基を指し、２価のイオウ、セレン、テルルを含まない化合物がより好ましい。ＬＰＵ′はＨ、炭素数１〜２０のアルキル基を指し、後述のＲ^２ と同じである。
該ＨＰＡＯの具体的化合物例を（１０）式のａ）〜ｃ）に、該ＰＥＯＤの具体的化合物例を（１１）式のａ）〜ｇ）に示した。
ここで置換基としては Ｃ_ｄ Ｈ_{２ ｄ＋１} ⁻ 、 Ｃ_ｄ Ｈ_{２ ｄ＋ １}ＣＯ ⁻ を挙げる事ができる。ｄは１〜１２の整数を表す。
【００５８】
【化７】

【００５９】
式中、ａ、ｂは１〜２５の整数を指し、ｎ_１ 〜ｎ_３ はＨＰＡＯおよびＰＥＯＤの前記分子量規定を満足する１〜１０，０００の値である。第１、第２態様の重合体のその他の詳細に関しては、特願平５−１１８４１８号の記載を参考にする事ができる。
該ＰＡＯ重合体の第３態様は、前記一般式（３）〔後述の（７）−ａ）式と同じである。〕で表されるモノマーの繰返し単位を有する重合体の少なくとも１種を含有させる態様である。該重合体は後述の他のモノマーとの共重合体でもよい。その場合、重合体中で（３）式のモノマーが占める割合は１〜１００重量％、好ましくは１０〜９０重量％である。該第４態様は重合体が一般式（３）で表されるモノマーと一般式（４）〔後述の（７）−ｃ）式と同じである〕で表されるモノマーの少なくとも２種の１：１００〜１００：１、好ましくは５〜１００〜１００：５モル比の共重合体である態様である。
【００６０】
該（３）式と（４）式において、Ｒ^１ 、Ｒ^４ は同じでも異なっていてもよく、Ｈ、炭素数１〜４の低級アルキル基（メチル、エチル、ｎ−プロピル、ｎ−ブチル）を表し、Ｈ、メチル基が特に好ましい。Ｒ^２ 、Ｒ^５ は同じでも異なっていてもよく、炭素数１〜２０の１価の置換基を表し、Ｈ、置換または無置換のアルキル基、置換または無置換のアリール基、アシル基が好ましく、特にＨ、メチル基、エチル基、フェニル基、アセチル基が好ましい。ｎ、ｍは繰返し単位の平均数を表し、ｎは４〜６００、好ましくは４〜２００、ｍは４〜６００、好ましくは４〜２００である。Ｌ、Ｌ′は２価の連結基を表し、具体例として−ＣＯＯ− 、−ＣＯＮＨ−、−ＣＯＮＨ−（ＣＨ_２） _Ｃ −ＣＯＯ− 、−Ｐｈ−ＣＨ_２Ｏ−（Ｐｈ： フェニレン基） 、−ＣＯＯＣＨ_２ＣＨ_２Ｏ−、−ＣＯＮ（ＣＨ_３）−、を挙げる事ができる。Ｃは１〜２０の整数を指す。
【００６１】
一般式（３）で表されるモノマーの具体例は次の通り。

【００６２】
一般式（４）で表されるモノマーの具体例は次の通り。

【００６３】
該共重合体中で （３）式で表されるモノマーの占める割合は１〜９０重量％、好ましくは５〜８５重量％、より好ましくは１５〜７０重量％である。
該共重合体中で （４）式のモノマーの占める割合は１〜９０重量％、好ましくは３〜７０重量％、より好ましくは１０〜５０重量％である。
（３）式のモノマーおよび／または （４）式のモノマーと他のモノマーを共重合して用いる事もできる。該他のモノマーの具体例はアクリル酸エステル類、メタクリル酸エステル類、アクリルアミド類、メタクリルアミド類、ビニルエステル類、ビニルケトン類、アリル化合物、オレフィン類、ビニルエーテル類、Ｎ−ビニルアミド類、ビニル異節環化合物、マレイン酸エステル類、イタコン酸エステル類、フマル酸エステル類、クロトン酸エステル類である。該他のモノマーの共重合量は０〜９９重量％、好ましくは０〜９０重量％、より好ましくは５〜６０重量％である。
【００６４】
（３）式のモノマーと （４）式のモノマーとその他のモノマーの共重合体の具体例を（１２）−１）〜（１２）−５）式に示した。カッコ内は重合体中における各モノマーの重量百分率を表す。

【００６５】
第３、第４態様のＰＡＯ重合体のその他の詳細に関しては後述の第６態様の記載、特願平５−１９１８１４号の記載を参考にする事ができる。
該ＰＡＯ重合体の第５態様は、該分散媒溶液が前記一般式（５）で表される繰返し単位を１重量％以上含有する重合体の少なくとも１種と、前記一般式（６）で表される繰返し単位を１重量％以上含有する重合体をそれぞれ前記濃度で含有する態様である。
該式中、Ｒは炭素数３以上、１０以下のアルキレン基を表し、具体例として−ＣＨ（ＣＨ_３）ＣＨ_２−、−ＣＨ_２ＣＨ（ＣＨ_３）−、−ＣＨ_２ＣＨ_２ＣＨ_２− 、−（ＣＨ_２）_４−、−（ＣＨ_２）_５−、−ＣＨ_２ＣＨ（Ｃ_６Ｈ_５）− を挙げる事ができ、−ＣＨ（ＣＨ_３）ＣＨ_２−、−ＣＨ_２ＣＨ（ＣＨ_３）−が特に好ましい。
ｎ、ｍは繰返し単位の平均数を表し、前記分子量規定を満たす４以上好ましくは６〜１０，０００、より好ましくは１０〜２０００の値である。
【００６６】
該ＰＡＯ重合体の第６態様は、第５態様に対し、次の限定が加わった態様である。 （５）式で表される重合体が、（７） −ａ）式で表されるモノマーのビニル重合体、および（７） −ｂ）式で表されるポリウレタンを含む重合体から選ばれる少なくとも１種の重合体であり、 （６）式で表される重合体が（７） −ｃ）式で表されるモノマーのビニル重合体、（７） −ｄ）式で表されるポリウレタンを含む重合体、および置換または未置換のポリエチレングリコールから選ばれる少なくとも１種の重合体である態様。
該式中、ｎ、ｍは４以上、好ましくは４〜６００、より好ましくは４〜８０の値をとりうる。Ｒ、Ｒ^１ 、Ｒ^２ 、Ｒ^４ 、Ｒ^５ 、Ｌ、Ｌ′は前記と同じである。Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４は２価の連結基を表し、炭素数１〜２０のアルキレン基、炭素数６〜２０のフェニレン基、または炭素数７〜２０のアラルキレン基を表す。ｘ、ｙ、ｚ、ｘ′、ｙ′、ｚ′は各成分の重量百分率を表し、ｘ、ｘ′は１〜７０、好ましくは５〜４０、ｙ、ｙ′は１〜７０、好ましくは３〜５０、ｚ、ｚ′は２０〜７０、好ましくは３０〜６０を表す。ここでｘ＋ｙ＋ｚ＝１００、ｘ′＋ｙ′＋ｚ′＝１００である。
−（Ｒ−Ｏ）−で表される繰り返し単位は、重合体中で１種のみが用いられてもよいし、２種以上であってもよい。また−（Ｒ−Ｏ）−あるいは −（ＣＨ_２ＣＨ_２Ｏ）−の繰返し単位の平均数（分子量）の異なる２種以上がそれぞれ用いられていてもよい。
【００６７】
（５）式で表される重合体としては （５）式の繰返し単位が含まれていれば好ましく用いる事ができるが、一般式（７） −ａ）で表されるモノマーのビニル重合体または、一般式（７） −ｂ）で表されるポリウレタンを含む重合体をより好ましく用いる事ができ、前者の該ビニル重合体を更に好ましく用いる事ができる。
（７） −ａ）式で表されるモノマーの具体例を（７）−ａ）−１） 〜（７）−ａ）−５） 式〔（３） −ａ）−１） 〜（３）−ａ）−５） 式と同じである〕に示した。
【００６８】
【化８】

【００６９】
該ビニル重合体において、（７） −ａ）で表されるモノマー単位の占める割合は１〜１００重量％、好ましくは、１０〜９０重量％、より好ましくは３０〜７０重量％である。（７） −ａ）式のモノマーの該ビニル重合体の具体例を（８）−ａ）−１） 〜（８）−ａ）−３） 式に、（７） −ｂ）式の該ポリウレタンの具体例を（８）−ｂ）−１） 〜（８）−ｂ）−２） 式に示した。カッコ内は重量百分率比を表す。
（８）−ａ）−１） ：（７）−ａ）−３）／アクリルアミド共重合体 （２５／７５）
（８）−ａ）−２） ：（７）−ａ）−３）／アクリル酸／アクリルアミド共重合体 （５０／３０／２０）
（８）−ａ）−３） ：（７）−ａ）−３）／アクリル酸共重合体 （７０／３０）
（８）−ｂ）−１） ：イソホロンジイソシアネート／２，２−ビス（ヒドロキシメチル）プロピオン酸ソーダ／ポリプロピレンオキシド（分子量４００）／ポリプロピレンオキシド（分子量１０００） （４３．１／２１．５／１５．７／１９．７）。
（８）−ｂ）−２） ：トルエンジイソシアネート／２，２−ビス（ヒドロキシメチル）ブタン酸ソーダ／ポリプロピレンオキシド（分子量１０００）
（２９．３／２０．１／５０．６） 。
該ポリウレタンは基本的にジオール化合物とジイソシアネート化合物の付加により合成される。
【００７０】
（６） 式で表される重合体としては（６） 式の繰返し単位が含まれていれば好ましく用いる事ができるが、一般式（７） −ｃ）で表されるモノマーの単独重合体、もしくは共重合体、あるいはポリエチレングリコール、置換ポリエチレングリコール、（７） −ｄ）式で表されるポリウレタンを好ましく用いる事ができ、（７）−ｃ）式のモノマーの該単独重合体をより好ましく用いる事ができる。
【００７１】
（７） −ｃ）式のモノマーは他のエチレン性不飽和モノマーと共重合してもよい。その場合、該共重合体において、（７） −ｃ）式のモノマーが占める割合は１〜１００重量％、好ましくは１０〜８０重量％、より好ましくは３０〜７０重量％である。（７） −ｃ）式で表されるモノマーの具体例は次の通り〔（４）−ａ）−１） 〜（４）−ａ）−５） と同じである。〕。

（６） 式で表される繰り返し単位を有する重合体としてはその他、ポリエチレングリコール、炭素数１〜３０の置換基を有する置換ポリエチレングリコール、ポリウレタンを挙げる事ができる。（７） −ｄ）式で表されるポリウレタン重合体中でポリエチレンオキシドが占める割合は１〜７０重量％、好ましくは５〜４０重量％である。
【００７２】
次に（７） −ｃ）式で表されるモノマーの重合体の具体例を（８） −ｃ）式に、（７） −ｄ）式の重合体例を（８） −ｄ）式に示す。
（８）−ｃ）−１） （７）−（ｃ）−３）／アクリルアミド共重合体 （１０／９０）
（８）−ｃ）−２） 〃 （２５／７５）
（８）−ｃ）−３） 〃 （５０／５０）
（８）−ｃ）−４） （７）−（ｃ）−３）単独共重合体
（８）−ｄ）−１） トルエンジイソシアネート／２，２−ビス（ヒドロキシメチル）ブタン酸ソーダ／ポリエチレングリコール（分子量１０００）
（２９．３／２０．１／５０．６）
（８）−ｄ）−２） ４，４′−ジフェニルメタンジイソシアネート／２，２−ビス（ヒドロキシメチル）プロピオン酸ソーダ／ポリエチレングリコール（分子量４００） （４５．３／１１．３／４３．４）
【００７３】
第５、第６態様のその他の詳細に関しては特願平５−２６３１２８号の記載を参考にする事ができる。
本発明では第１態様のＨＰ１、第２〜第６態様を好ましく用いる事ができ、第２〜第６態様をより好ましく用いる事ができ、第３〜６態様を更に好ましく用いる事ができる。更には第５、第６態様がもっとも好ましい。
前記ＰＡＯ重合体のその他の詳細に関しては Ｄａｖｉｄｓｏｈｎら、Ｓｙｎｔｈｅｔｉｃ Ｄｅｔｅｒｇｅｎｔｓ， Ｊｏｈｎ Ｗｉｌｅｙ ＆ Ｓｏｎｓ， Ｎｅｗ Ｙｏｒｋ （１９８７）、三沢忠則編， 水溶性高分子，化学工業社（１９９０）、堀口博著，新界面活性剤，三共出版（１９７５）、藤本武彦著，新界面活性剤入門，三洋化成工業（１９７６）、日本化学会編，化学便覧，第４−６節，丸善（１９８４）、吉田時行ら著，界面活性剤ハンドブック，工学図書、および後述の文献の記載を参考にする事ができる。
ＡｇＸ粒子のハロゲン組成や成長条件（温度、ｐＨ、ｐＡｇ等）により、（５） 式で表される重合体と（６） 式で表される重合体の最適添加量比が変化する。しかし、第５、第６態様の場合、両重合物を準備しておけば、その添加量比を変える事により、最適条件を選ぶ事ができる。しかし、第４態様の場合、（３） 式のモノマーと（４） 式のモノマーの重合比を種々変化させた重合物を準備しなければならず、きめ細かく対応する事が困難である。また、少量多品種化し、コストアップになる。従って、この点では第４態様より、第５、第６態様の方がより好ましい。
【００７４】
Ｄ．Ａｇ^＋ とＸ⁻ の供給方法
成長過程でのＡｇ^＋ とＸ⁻ の供給方法は、１）可溶性銀塩を溶解させた銀塩溶液と可溶性ハロゲン塩を溶解させたハロゲン塩溶液（以後「Ｘ⁻ 塩液」と記す）を供給するイオン溶液添加法、２）予めＡｇＸ微粒子乳剤を形成し、該微粒子乳剤を供給する方法、３）スプラッシュ添加方法、４）前記両者の併用方法、をあげることができる。可溶性銀塩、可溶性ハロゲン塩としては室温の水に対する溶解度が１重量％以上、好ましくは１０重量％以上の塩をあげることができ、日本化学会編，化学便覧，第８章，丸善（１９９３年）の記載を参考にすることができる。通常はＡｇＮＯ_３ と、Ｃｌ⁻ 、Ｂｒ⁻ 、Ｉ⁻ のアルカリ金属塩、アンモニウム塩を好ましく用いることができる。ＡｇＸ微粒子としては粒子の直径（粒子の投影面積と等しい面積を有する円の直径）が０．１５μｍ以下が好ましく、０．０１〜０．１μｍがより好ましく、０．０２〜０．０６μｍが更に好ましい。ハロゲン組成はＡｇＣｌ、ＡｇＢｒ、ＡｇＩおよびその２種以上の混晶をあげることができる。
【００７５】
該サイズ分布は変動係数で０〜０．４が好ましく、０〜０．２がより好ましく、０〜０．１が更に好ましい。
該微粒子は２重以上の双晶面を実質的に有しないことが好ましく、１重双晶粒子をも実質的に有しないことがより好ましい。更にはらせん転位欠陥をも実質的に有しないことが好ましい。ここで実質的に有しないとは個数で３％以下が好ましく、１％以下がより好ましく、０〜０．１％が更に好ましい。
該微粒子は連続的に添加する事もできるし、断続的に添加する事もできる。また、供給する該微粒子のハロゲン組成は供給時間に対して連続的に変化させる事もできるし、断続的に変化させることもできる。該微粒子乳剤のｐＨは１〜１２、ｐＸは０．５〜６の最も好ましい組合せを選ぶことができる。
【００７６】
該微粒子を形成する場合、ＡｇＸ粒子に強く吸着する分散媒の方が、前記規定の微粒子の形成を可能にする。一方、該微粒子を供給して平板粒子を成長させる場合、分散媒とＡｇＸ粒子の結合は弱い方がよい。それは該微粒子の溶解を促進し、平板粒子の成長を促進する為である。従って、該ＡｇＸ微粒子を分散媒溶液中で形成した後、該処理をし、同一条件下における該分散媒の単位重量あたりのＡｇ^＋ との錯体形成能を１０％以上、好ましくは３０〜９９％以上、より好ましくは６０〜９５％、更に好ましくは８０〜９５％だけ低下させることが好ましい。ここで該処理とはＨ_２ Ｏ_２ 等の酸化剤を添加し、分散媒を酸化する事および／または該修飾剤を添加し、該アミノ基を該化学修飾する事を指す。該処理の詳細、および、該微粒子添加法のその他の詳細に関しては特願平６−１０２４８５の記載を参考にする事ができる。
【００７７】
核形成、熟成、成長時の該Ａｇ^＋ とＸ⁻ の供給装置および該粒子形成装置としては従来公知のあらゆる装置を用いることができる。添加孔が分散媒溶液中に設置され、（添加孔数／１添加液）が２個以上、好ましくは４〜１０^１５個の多孔添加系、該添加孔がゴム弾性体膜ででき、添加時には孔が開となり、添加停止時には孔が閉となる態様を好ましく用いる事ができる。前記微粒子添加法および従来の装置の詳細に関しては後述の文献、および特開平３−２１３３９、同１−１８３４１７、同４−３４５４４、同４−１９３３３６、同４−３３０４２７、同３−１５５５３９、同３−２００９５２、同３−２４６５３４、同４−２８３７４１、同４−１８４３２６〜１８４３３０、同５−１１３７７、同５−４５７５７、同５−６１１３４、同５−３３７３５０、同６−１１７７９、米国特許第５２５４４５４、特願平４−２４０２８３、同４−３０２６０５、同５−２５３１４の記載を参考にする事ができる。
【００７８】
Ｅ．ＡｇＸ乳剤の製造工程
ＡｇＸ乳剤の製造工程は従来は通常、ＡｇＸ粒子形成→乳剤水洗→化学増感、分光増感、で行なわれている。本発明では、この製造工程以外に、目的に応じて、化学増感後、および／または分光増感後に乳剤の脱塩工程を入れることができる。この場合、化学増感時のＡｇＸ乳剤条件、分光増感時のＡｇＸ乳剤条件を、塗布時のＡｇＸ乳剤条件とは異なる条件に選ぶことができ、それぞれの工程に最も適した条件を選ぶことができるという利点がある。化学増感と分光増感は同時に行なうこともでき、いずれか一方を先に行なうこともできる。
該乳剤を調製した後、従来法に従って乳剤を水洗し、脱塩する事ができる。該脱塩法としては、１）ヌーデル水洗法、２）凝集剤を加え、乳剤のｐＨを凝集ｐＨに調節して乳剤を凝集させ、沈降させ、上澄み液を除去する方法、−ＮＨ_２ 基および／またはカルボキシル基、好ましくは−ＮＨ_２ 基を化学修飾したゼラチンを含む場合は、凝集剤なし、またはより少ない添加量で凝集、沈降させる事ができる。３）限外濾過膜を用いてＡｇＸ乳剤中の水溶液を除去する方法、４）遠心沈降法によりＡｇＸ粒子を沈降させ、上澄み液を除去する方法、５）遠心濾過法、６）電気透析法、を挙げる事ができる。それらの詳細に関しては後述の文献、特公昭６２−２７００８号、特開昭６２−１１３１３７号、特開平３−２００９５２号、三沢編，増補・遠心分離，化学工業社（１９８５年）の記載を参考にする事ができる。
本発明の乳剤の場合、該遠心濾過法を用い、分散媒の１０〜９９．９％を除去し、新しい分散媒を添加し、分散媒を置換する方法も好ましく用いる事ができる。
【００７９】
Ｆ．化学増感
本発明のＡｇＸ乳剤粒子は好ましくはＳｘ増感され、分光増感色素を吸着しているが、ここでＳｘとはイオウ、セレン、テルルを指す。Ｓｘ増感剤としては従来公知のＳｘ増感剤を用いることができ、具体例としてはチオ尿素類、ローダニン類、オキサゾリジン類、ポリスルフィド類、セレノ尿素類、ホスフィンセレニド類、セレノアミド類、チオ硫酸塩をあげることができ、詳細は後述の文献の記載を参考にすることができる。
本発明のＡｇＸ乳剤のＡｇＸ粒子は更に金増感されていることが好ましい。金増感剤としては従来公知の金増感剤を用いることができ、例えば塩化金酸、カリウムクロロオーレート、カリウムまたはナトリウムオーリチオシアネート（塩化金酸：ＳＣＮ⁻ ＝１：１〜１：１００モル比）、臭化金酸、ヨウ化金酸、硫化金、金セレナイド等をあげることができ、詳細は後述の文献の記載を参考にすることができる。
なお、（金増感剤の添加モル数／Ｓｘ増感剤の添加モル数）の比は４〜０．２が好ましく、２〜０．３がより好ましく、１．５〜０．４が更に好ましい。ＡｇＸ乳剤への添加量はそれぞれ、１０^−２〜１０^−７、好ましくは１０^−３〜１０^−７モル／モルＡｇＸの中から最適量を選ぶ事が好ましい。
【００８０】
Ｇ．その他
核形成、熟成時の分散媒、また成長時に併存させる分散媒としては従来公知の水溶性分散媒の中から１種以上を選んで用いる事ができ、ゼラチンを好ましく用いる事ができる。従来公知の水溶性分散媒に関しては後述の文献およびＲｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ ，３０７巻，アイテム３０７１０５，１１月，１９８９年、特願平６−１０２４８５、特公昭５２−１６３６５、三沢忠則編，水溶性高分子，化学工業社（１９８７年），高分子学会編，高分子新素材，Ｏｎｅ Ｐｏｉｎｔ ２４，共立出版（１９９０）、長友信治編，水溶性高分子の応用と市場，シーエムシー社（１９８４）、Ｗａｒｄら著， Ｔｈｅ Ｓｃｉｅｎｃｅ ａｎｄ Ｔｅｃｈｎｏｌｏｇｙ ｏｆ Ｇｅｌａｔｉｎ， Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ， Ｌｏｎｄｏｎ （１９６４）、の記載を参考にする事ができる。分散媒の濃度は０．０１〜１０重量％、好ましくは０．０５〜３重量％の内の好ましい濃度を選んで用いる事ができる。
【００８１】
このようにして調製した本発明の平板粒子乳剤は、該成長終了直後の状態は、次の如く表現される。少なくとも分散媒とＡｇＸ粒子を有するＡｇＸ乳剤において、該ＡｇＸ粒子の全投影面積の７５〜１００％、好ましくは９０〜１００％、より好ましくは９７〜１００％が、厚さが０．０２〜０．３μｍ、好ましくは０．０３〜０．１５μｍ、より好ましくは０．０３〜０．１μｍ、アスペクト比（直径／厚さ）が２〜５０、好ましくは３〜３０の平板粒子であり、直径分布の変動係数が０〜０．３、好ましくは０〜０．２、より好ましくは０〜０．１であり、該分散媒の３０〜１００重量％、好ましくは６０〜１００重量％、より好ましくは９０〜１００重量％が（化学修飾された−ＮＨ_２ 基数の％と、メチオニン含率の関係が図１のａ_１ の領域、好ましくはａ_２ の領域、より好ましくはａ_３ の領域にあるゼラチン）である。メチオニン含率に関しては前記Ｃ項の記載を参考にする事ができる。更には該平板粒子の厚さの分布の変動係数は０〜０．３が好ましく、０〜０．２がより好ましく、０〜０．１が更に好ましい。
【００８２】
このようにしてＡｇＸ粒子が形成された後、該ＡｇＸ粒子は通常、水洗、化学増感される。更には分光増感剤、かぶり防止剤等の写真的に有効な添加剤が添加され、支持体上に塗布される。化学増感剤、分光増感用色素およびかぶり防止剤の添加の順序は、それぞれの目的に応じて最適の順序を選ぶことができる。該色素を添加する場合、粒子間で吸着被覆率のバラツキを少なくして均一に吸着させることが好ましい。この場合、添加した色素の吸着速度を適度に遅くした方がよい。即ち、添加した色素がより均一に混合化された後に吸着が進行した方が、該均一性が高まる。色素がＡｇＸ粒子に吸着する時に要する活性化エネルギーは、吸着した分散媒分子との交換吸着エネルギーである。それは主として分散媒分子の脱着の活性化エネルギーである。
【００８３】
従って、該色素吸着速度を遅くするには、該脱着の活性化エネルギーのより大きい分散媒を用い、より低温で該色素を含む溶液をＡｇＸ乳剤に添加すればよい。この場合、前記粒子形成後から、該色素添加までの間に、新たに分散媒を添加することができるし、分散媒の一部もしくは全部を除去した後に新たに分散媒を加えることができる。このようにして、分散媒の種類、温度、ｐＨ、ｐＡｇを調節する事によって分散媒の吸着強度を最適に調製した後、ＡｇＸ乳剤中に設置した中空管型ゴム弾性体多孔膜を通して、激しく攪拌しながら該色素溶液を瞬時に添加する。この場合、混合装置としては（気／液）界面を実質的になくした混合装置を用いる事が好ましい。激しく混合しても、発泡量が抑えられる。具体的には▲１▼添加液の添加量と共に元の容積の１．０５倍以上、好ましくは１．１〜６倍に膨張可能な反応容器を用い、反応容器内の（気相部の体積／反応容器内の総容積）を好ましくは０〜０．３、より好ましくは０〜０．１５、更に好ましくは０とする態様、▲２▼混合溶液表面に該表面の総面積の好ましくは１０％以上、より好ましくは２５〜９９％、更に好ましくは５０〜９８％を覆う浮きブタを設置する態様、であり、その他の詳細は特願平４−３０２６０５号明細書の記載を参考にすることができる。
【００８４】
本発明のＡｇＸ乳剤の分光増感後の好ましい態様は次の通りである。
１）少なくとも分光増感色素を吸着したＡｇＸ粒子と分散媒を有するＡｇＸ乳剤において、該ＡｇＸ粒子の投影面積の７５〜１００％、好ましくは９０〜１００％、より好ましくは９７〜１００％がアスペクト比が２〜５０、好ましくは４〜３０、厚さが０．０２〜０．３μｍ、好ましくは０．０３〜０．１５μｍ、より好ましくは０．０３〜０．１μｍの平板粒子であり、その直径分布の変動係数が０〜０．３、好ましくは０〜０．２、より好ましくは０〜０．１であり、該色素の吸着被覆率の変動係数が０〜０．３、好ましくは０〜０．２、より好ましくは０〜０．１である。
本発明のＡｇＸ乳剤は少なくとも金で増感されている事が好ましい。この場合の好ましい態様は次の通り。２）１０^−７モル／モルＡｇＸ以上の金増感剤で増感されたＡｇＸ粒子と、分散媒を有するＡｇＸ乳剤において、該ＡｇＸ粒子の投影面積の７５〜１００％、好ましくは９０〜１００％、より好ましくは９７〜１００％が前記規定に従う平板粒子であり、該平板粒子の金の含有率が該平板粒子の表面積に比例しており、該比例定数の粒子間バラツキの変動係数が０〜０．３、好ましくは０〜０．２、より好ましくは０〜０．１である。
【００８５】
本発明のＡｇＸ乳剤は少なくともセレンで増感されている事が好ましい。この場合の好ましい態様は次の通り。３）１０^−７モル／モルＡｇＸ以上のセレン増感剤で増感されたＡｇＸ粒子と、分散媒を有するＡｇＸ乳剤において、該ＡｇＸ粒子の投影面積の７５〜１００％、好ましくは９０〜１００％、より好ましくは９７〜１００％が前記規定に従う平板粒子であり、該平板粒子のセレンの含有率が該平板粒子の表面積に比例しており、該比例定数の粒子間バラツキの変動係数が０〜０．３、好ましくは０〜０．２、より好ましくは０〜０．１である。
【００８６】
前記１）〜３）の２つ以上、好ましくは３つが満足されたＡｇＸ乳剤がより好ましい。
前記規定に従った化学増感核を形成する為に、特に次の方法を好ましく用いることができる。従来は先ず、ＡｇＸ乳剤を化学熟成温度に昇温し、次に化学増感剤をＡｇＸ乳剤の液面上に添加し、化学熟成していた。この場合、化学増感剤の高濃度液と接したＡｇＸ粒子の化学増感反応は急速に進行し、化学増感核形成が粒子間で不均一になる。ＡｇＸ乳剤の温度を下げたり、ｐＡｇを上げたり、ｐＨを下げると、該反応速度は低下する。従って本発明では添加した化学増感剤が実質的に反応しない条件でＡｇＸ乳剤に化学増感剤を添加し、均一化した後、ＡｇＸ乳剤を該反応が進行する条件に変化させ、該反応を進行させる。即ち、温度が低温の場合は昇温し、ｐＡｇが高い場合は下げ、ｐＨが低い場合には上げる。
セレン増感剤と金増感剤はＡｇＸ乳剤中で全く、均一であるから、すべてのＡｇＸ粒子上の単位面積部が化学増感剤と反応するチャンスは全く同じであり、本発明の目的が達せられる。
前記均一化学増感法、および均一分光増感法に関するその他の詳細、該均一性の検証法の詳細に関しては、特願平５−３２４５０２号の記載を参考にする事ができる。
【００８７】
従来、分散媒とＡｇＸ粒子を有するＡｇＸ乳剤において、該ＡｇＸ粒子の全投影面積の９０〜１００％、好ましくは９６〜１００％、より好ましくは９８〜１００％が厚さが０．０２〜０．１２μｍ、好ましくは０．０２〜０．１μｍ、アスペクト比が３〜５０、好ましくは４〜５０の六角平板粒子であり、該粒子の直径分布の変動係数が０〜０．２、好ましくは０〜０．１、主平面の形状が、最大隣接辺比率１〜１．５、好ましくは１〜１．２、より好ましくは１〜１．１であるＡｇＸ乳剤は製造された事がない。本発明法を用いて、該乳剤の製造が初めて可能となった。該乳剤を特に好ましく用いる事ができる。
前記（１００）平板粒子を−１００℃以下で透過型電子顕微鏡で観察すると、図２、即ち図３（ａ）に示す粒子像が観察される事がある。この粒子は、Ｍｉｇｎｏｔ， Ｊｏｕｒｎａｌ ｏｆ Ｃｒｙｓｔａｌ Ｇｒｏｗｔｈ， ２３巻，２０７（１９７４年）に記載された２本のらせん転位を含有する態様の粒子に見える。しかし、観察された該欠陥像が、らせん転位線ならば、図３（ｂ）の如くに観察されるはずである。図３（ｂ）に対応する粒子も観察される事があるが、多くの場合、該転位線と異方成長の両ベクトルは必ずしも一致していない。転位線のベクトルはエッジの（１００）面に対し、９０°または６５〜７５°である事が多い。該手法で観察される種々の転位線の観察例を図４に示した。
【００８８】
該らせん転位欠陥は、その他、次の手法で観察できる。即ち、該平板粒子を含むＡｇＸ乳剤を下塗りした平坦な支持体上に塗布し、乾燥させる。乾燥により膜厚が約１／１０に減少する為、平板粒子は支持体と平行に配列する。次に該試薬を−５０℃以下、好ましくは−１００〜−２００℃に冷却し、ミクロトームで裁断し、０．１μｍ以下の厚さの切片を作る。該切片を−１００℃以下に冷却し、その粒子断面の透過型電子顕微鏡写真像を観察する。試料の同じ領域をそのまま透過した電子線と、格子原子に回折されて透過した電子線の干渉像を観察する事により、その格子像を観察する事ができる。いくつかの切片の該像を観察すると、らせん転位線が該切片を通過する点が観察される。該格子像の観察方法に関しては堀内繁雄著，高分解能電子顕微鏡，共立出版（１９８８）、の記載を参考にする事ができる。この場合、大部分の電子線は試料を透過するので、試料のチャージアップは少ない。
【００８９】
ＡｇＸ粒子への分散媒の吸着状態に関してはＡｇＸ粒子のイオン電導度を測定する事によりその一端を理解する事ができる。誘電損失法でゼラチン中に分散されたＡｇＸ粒子の格子間銀イオンＡｇｉのイオン電導度を測定した場合、乳剤のｐＨをｐＨ７→４にＨＮＯ_３ 液で下げた場合、立方体ＡｇＢｒ粒子のイオン電導度は上昇する。これはゼラチンの−ＮＨ_２ 基が−ＮＨ_３ ^＋ となり、粒子表面のＡｇ^＋ への吸着性が低下する為と考えられる。一方、八面体ＡｇＢｒ粒子の場合は該ｐＨ変化で、該イオン電導度は上昇する。この場合、ゼラチンの−ＮＨ_３ ^＋ と粒子表面のＢｒ⁻ 間のクーロン吸着性が増し、ゼラチンの吸着性が増す。これは粒子表面が殆んどＢｒ⁻ で占められている為、該クーロン相互作用力が吸着力のメインになる為と解される。吸着が強化される事により始めて、ゼラチン中の−Ｓ−等と、Ａｇ^＋ が相互作用できるようになる事が考えられる。更には、表面Ｂｒ⁻ の負電荷とバランスして存在していたＡｇｉ^＋ が、該負電荷が中和される事により、クーロン的に不要になり、該濃度が減少する事が考えられる。
【００９０】
得られた粒子をホスト粒子とし、該粒子のエッジおよび／またはコーナーにエピタキシャル粒子を形成して用いてもよい。また、該粒子をコアとして内部に転位線を有する粒子を形成してもよい。その他、該粒子をサブストレートとして、サブストレートと異なるハロゲン組成のＡｇＸ層を積層させ、種々の既知のあらゆる粒子構造の粒子を作ることもできる。これらに関しては後述の文献の記載を参考にすることができる。また、得られた乳剤粒子に対し、通常、化学増感核が付与される。
【００９１】
この場合、該化学増感核の生成場所と数／ｃｍ^２ が制御されていることが好ましい。これに関しては特開平２−８３８号、同２−１４６０３３号、同１−２０１６５１号、同３−１２１４４５号、特開昭６４−７４５４０号、特願平３−７３２６６号、同３−１４０７１２号、同３−１１５８７２号の記載を参考にすることができる。
【００９２】
また、該平板粒子をコアとして、浅内潜乳剤を形成して用いてもよい。また、コア／シェル型粒子を形成することもできる。これについては特開昭５９−１３３５４２号、同６３−１５１６１８号、米国特許第３，２０６，３１３号、同３，３１７，３２２号、同３，７６１，２７６号、同４，２６９，９２７号、同３，２６７，７７８号の記載を参考にすることができる。
本発明の方法で製造したＡｇＸ乳剤粒子を他の１種以上のＡｇＸ乳剤とブレンドして用いることもできる。ブレンド比率は１．０〜０．０１の範囲で適宜、最適比率を選んで用いることができる。
【００９３】
これらの乳剤に粒子形成から塗布工程までの間に添加できる添加剤に特に制限はなく、従来公知のあらゆる写真用添加剤を好ましくは１０^−８〜１０^−１ｍｏｌ／ｍｏｌ ＡｇＸの添加量で添加することができる。例えばＡｇＸ溶剤、ＡｇＸ粒子へのドープ剤（例えば第８族貴金属化合物、その他の金属化合物、カルコゲン化合物、ＳＣＮ化物等）、分散媒、かぶり防止剤、増感色素（青、緑、赤、赤外、パンクロ、オルソ用等）、強色増感剤、化学増感剤（イオウ、セレン、テルル、金および第８族貴金属化合物、リン化合物、ロダン化合物、還元増感剤の単独およびその２種以上の併用）、かぶらせ剤、乳剤沈降剤、界面活性剤、硬膜剤、染料、色像形成剤、カラー写真用添加剤、可溶性銀塩、潜像安定剤、現像剤（ハイドロキノン系化合物等）、圧力減感防止剤、マット剤等を挙げることができる。
【００９４】
本発明のＡｇＸ乳剤粒子および製造方法で製造したＡｇＸ乳剤は従来公知のあらゆる写真感光材料に用いることができる。例えば、黒白ハロゲン化銀写真感光材料〔例えば、Ｘレイ感材、印刷用感材、印画紙、ネガフィルム、マイクスフィルム、直接ポジ感材、超微粒子乾板感材（ＬＳＩフォトマスク用、シャドーマスク用、液晶マスク用）〕、カラー写真感光材料（例えばネガフィルム、印画紙、反転フィルム、直接ポジカラー感材、銀色素漂白法写真など）に用いることができる。更に拡散転写型感光材料（例えば、カラー拡散転写要素、銀塩拡散転写要素）、熱現像感光材料（黒白、カラー）、高密度 ｄｉｇｉｔａｌ記録感材、ホログラフィー用感材などをあげることができる。
【００９５】
塗布銀量は０．０１ｇ／ｍ^２以上の好ましい値を選ぶことができる。該写真感光材料の構成（例えば、層構成、銀／発色材モル比、各層間の銀量比等）、露光、現像処理および写真感光材料の製造装置、写真用添加剤の乳化分散等に関しても制限はなく、従来公知のあらゆる態様、技術を用いることができる。従来公知の写真用添加剤、写真感光材料およびその構成、露光と現像処理、および写真感光材料製造装置等に関しては下記文献の記載を参考にすることができる。
【００９６】
リサーチ・ディスクロージャー（Ｒｅｓｅａｒｃｈ Ｄｉｓｃｌｏｓｕｒｅ）、１７６巻（アイテム１７６４３）（１２月、１９７８年）、同３０７巻（アイテム３０７１０５、１１月、１９８９年）ダフィン（Ｄｕｆｆｉｎ）著、写真乳剤化学 （Ｐｈｏｔｏｇｒａｐｈｉｃ Ｅｍｕｌｓｉｏｎ Ｃｈｅｍｉｓｔｒｙ）、Ｆｏｃａｌ Ｐｒｅｓｓ， Ｎｅｗ Ｙｏｒｋ （１９６６年）、ビル著（Ｅ． Ｊ． Ｂｉｒｒ）、写真用ハロゲン化銀乳剤の安定化（Ｓｔａｂｉｌｉｚａｔｉｏｎ ｏｆ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｓｉｌｖｅｒ Ｈａｌｉｄｅ Ｅｍｕｌｓｉｏｎ）、フォーカル・プレス（Ｆｏｃａｌ Ｐｒｅｓｓ） 、ロンドン（１９７４年）、ジェームス編（Ｔ． Ｈ． Ｊａｍｅｓ） 、写真過程の理論（Ｔｈｅ Ｔｈｅｏｒｙ ｏｆ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓ）第４版、マクミラン（Ｍａｃｍｉｌｌａｎ） 、ニューヨーク（１９７７年）
【００９７】
グラフキデ著（Ｐ． Ｇｌａｆｋｉｄｅｓ）、写真の化学と物理（Ｃｈｉｍｉｅ ｅｔ Ｐｈｙｓｉｑｕｅ Ｐｈｏｔｏｇｒａｐｈｉｑｕｅｓ）、第５版、エディション・ダ・リジンヌヴェル（Ｅｄｉｔｉｏｎ ｄｅ Ｉ’ Ｕｓｉｎｅ Ｎｏｕｖｅｌｌｅ， パリ（１９８７年）同第２版、ポウル・モンテル、パリ（１９５７年）、ゼリクマンら（Ｖ． Ｌ． Ｚａｌｉｋｍａｎ ａｔ ａｌ．） 、写真乳剤の調製と塗布（Ｍａｋｉｎｇ ａｎｄ Ｃｏａｔｉｎｇ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｅｍｕｌｓｉｏｎ）、Ｆｏｃａｌ Ｐｒｅｓｓ （１９６４年）、ホリスター（Ｋ． Ｒ． Ｈｏｌｌｉｓｔｅｒ） ジャーナル・オブ・イメージング・サイエンス（Ｊｏｕｒｎａｌ ｏｆ Ｉｍａｇｉｎｇ ｓｃｉｅｎｃｅ） 、３１巻、ｐ．１４８〜１５６（１９８７年）、マスカスキー（Ｊ． Ｅ． Ｍａｓｋａｓｋｙ）、同３０巻、ｐ．２４７〜２５４（１９８６年）、同３２巻、１６０〜１７７（１９８８年）、同３３巻、１０〜１３（１９８９年）
【００９８】
フリーザーら編、ハロゲン化銀写真過程の基礎（Ｄｉｅ Ｇｒｕｎｄｌａｇｅｎ Ｄｅｒ Ｐｈｏｔｏｇｒａｐｈｉｓｃｈｅｎ Ｐｒｏｚｅｓｓｅ Ｍｉｔ Ｓｉｌｖｅｒｈａｌｏｇｅｎｉｄｅｎ）、アカデミッシェ・フェルラークゲゼルシャフト（Ａｋａｄｅｍｉｓｃｈｅ Ｖｅｒｌａｇｇｅｓｅｌｌｓｃｈａｆｔ）、フランクフルト（１９６８年）。
日化協月報１９８４年、１２月号、ｐ．１８〜２７、日本写真学会誌、４９巻、７〜１２（１９８６年）、同５２巻、１４４〜１６６（１９８９年）、同５２巻、４１〜４８（１９８９年）、特開昭５８−１１３９２６〜１１３９２８号、同５９−９０８４１号、同５８−１１１９３６号、同６２−９９７５１号、同６０−１４３３３１号、同６０−１４３３３２号、同６１−１４６３０号、同６２−６２５１号、同６３−２２０２３８号、同６３−１５１６１８号、同６３−２８１１４９号、同５９−１３３５４２号、同５９−４５４３８号、同６２−２６９９５８号、同６３−３０５３４３号、同５９−１４２５３９号、同６２−２５３１５９号、同６２−２６６５３８号、同６３−１０７８１３号、同６４−２６８３９号、同６２−１５７０２４号、同６２−１９２０３６号、
【００９９】
特開平１−２９７６４９号、同２−１２７６３５号、同１−１５８４２９号、同２−４２号、同２−２４６４３号、同１−１４６０３３号、同２−８３８号、同２−２８６３８号、同３−１０９５３９号、同３−１７５４４０号、同３−１２１４４３号、同２−７３２４５号、同３−１１９３４７号、米国特許第４，６３６，４６１号、同４，９４２，１２０号、同４，２６９，９２７号、同４，９００，６５２号、同４，９７５，３５４号、欧州特許第０３５５５６８Ａ２号、特願平２−３２６２２２号、同２−４１５０３７号、同２−２６６６１５号、同２−４３７９１号、同３−１６０３９５号、同２−１４２６３５号、同３−１４６５０３号、同４−７７２６１号。
本発明の乳剤は特開昭６２−２６９９５８号、同６２−２６６５３８号、同６３−２２０２３８号、同６３−３０５３４３号、同５９−１４２５３９号、同６２−２５３１５９号、特開平１−１３１５４１号、同１−２９７６４９号、同２−４２号、同１−１５８４２９号、同３−２２６７３０号、同４−１５１６４９号、特願平４−１７９９６１号、欧州特許０５０８３９８Ａ１号、特開平６−２５８７８８号、同６−２７３８６０号の実施例の感光材料の構成乳剤として好ましく用いることができる。
【０１００】
【発明の実施の形態】
【０１０１】
【実施例】
次に実施例により本発明を更に詳細に説明するが、本発明の実施態様はこれに限定されるものではない。
実施例１
反応容器にゼラチン溶液１〔Ｈ_２ Ｏ １．２リットル、ゼラチン１を１．０ｇ、ＫＢｒ ０．２５ｇを含み、ＨＮＯ_３ ３Ｎ液でｐＨ２．０に調節した〕を入れ、温度を４０℃に保ち、攪拌しながらＡｇ−１液（ＡｇＮＯ_３ ６０ｇ／リットル）とＸ−１液（Ｈ_２ Ｏ １リットル，ＫＢｒ ４３．２ｇ，ゼラチン１を０．８ｇ含む）を３０ｍｌ／分で１分間添加し、核形成した。２分間攪拌した後、ＫＢｒ−１液（ＫＢｒ １００ｇ／リットル）を３０ｍｌ添加し、１０分間で６０℃に昇温した。更に１２分間、第１熟成した後、硫安液〔（ＮＨ_４ ）_２ ＳＯ_４ ４ｇ，Ｈ_２ Ｏ ２０ｍｌを含む〕とＮａＯＨ １Ｎ液を入れ、ｐＨ９．１とした。１０分間、第２熟成をした後、ゼラチン溶液２〔ゼラチン２を２５ｇ、Ｈ_２ Ｏ １３０ｍｌ，ＫＢｒ ０．１５ｇ含む〕を入れ、ＨＮＯ_３ ３Ｎ液でｐＨ６．３とした。この時、分散媒の９６．１重量％がフタル化率９６％、メチオニン含率３４μｍｏｌ／ｇ のゼラチンとなる。Ａｇ−１液とＸ−１液を用い、ｐＢｒ１．６８に保ちながら同時混合添加した。Ａｇ−１液は６．６ｍｌ／分で８０ｍｌ添加した。次にＡｇ−２液（ＡｇＮＯ_３ ２００ｇ／リットル）とＸ−２液（１４６ｇ／リットル）を用い、同ｐＢｒに保ちながら同時混合添加した。Ａｇ−２液は初期流量３ｍｌ／分、直線流量加速０．３ｍｌ／分で４０分間添加した。１分間攪拌した後、乳剤３ｍｌをサンプリングし、生成粒子のレプリカの透過型電子顕微鏡写真像（ＴＥＭ像）を観察した。その特性値は次の通りであった。
全ＡｇＸ粒子の投影面積の合計（以後、「ＳＡ」と記す）の９９％以上が最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．０５μｍ、平均直径２．１μｍ、平均アスペクト比４２、Ｃ．Ｖ．値は０．０９であった。
【０１０２】
次に該乳剤を３０℃に降温し、ＨＮＯ_３ １Ｎ液でｐＨ３．９に下げ、乳剤を凝集沈降させた。乳剤を純水で３回水洗し、ゼラチン溶液を添加した。ＮａＯＨ１Ｎ液でｐＨ６．４にし、ＮａＢｒ １Ｎ液でｐＢｒ２．８にし、乳剤を再分散させた。該乳剤を特願平５−３２４５０２号の実施例１記載の密閉型容積可変容器に入れ、４０℃で攪拌しながら増感色素１の０．３ｇ／リットル溶液を飽和吸着量の７０％だけ添加した。該実施例と同態様で該中空管型弾性体多孔膜を通して３秒間以内で全量を添加した。１５分間攪拌した後、２番目の密閉型容積可変容器に移液した。乳剤の温度を４５℃に保ちながら金増感剤（塩化金酸：ＮａＳＣＮ＝１：２０モル比の水溶液）を１．２×１０^−５モル／モルＡｇＸだけ添加し、次にカルコゲナイド増感剤Ｓｘ１を２×１０^−５モル／モルＡｇＸだけ添加した。それぞれ独立の、前記態様の中空管型弾性多孔膜より３秒間以内で添加した。
該乳剤の温度を６０℃に昇温し、２０分間熟成した。４０℃に降温し、かぶり防止剤（４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデン）を３×１０^−３モル／モルＡｇＸだけ添加し、増粘剤、塗布助剤を加えて保護層と共に、ＴＡＣ（三酢酸セルロース）ベース上に塗布し、乾燥し、塗布試料１とした。
但し、ゼラチン１は重量平均分子量３０，０００、メチオニン含率３４μｍｏｌ／ｇ の脱イオン化アルカリ処理骨ゼラチン、ゼラチン２はゼラチン１をフタル化率９６％でフタル化したゼラチン、ゼラチン３はメチオニン含率５０μｍｏｌ／ｇ 脱イオン化アルカリ処理非修飾骨ゼラチンを指す。
【０１０３】
【化９】

【０１０４】
実施例２
ゼラチン溶液２にＥＰＡ１を１．０ｇ混入する事以外は実施例１と同じにした。乳剤３ｍｌをサンプリングし、生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。
ＳＡの９９％以上が最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．０９μｍ、平均直径１．５６μｍ、平均アスペクト比約１７、Ｃ．Ｖ．値は０．０７５であった。後は実施例１と同じ態様で処理し、塗布試料２を得た。ここでＥＰＡ１は（３）−ａ）−２） 式の化合物：（４）−ａ）−４） 式の化合物：アクリルアミド＝２５：２５：５０重量％比の共重合体であり、重量平均分子量は３３，０００である。
【０１０５】
実施例３
ゼラチン溶液２にＥＰＡ２とＥＰＡ３を１．０ｇづつ混入する事以外は実施例１と同じにした。生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。ＳＡの９９％以上が最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．０９μ、平均直径１．５６μｍ、平均アスペクト比約１７、Ｃ．Ｖ．値は０．０７であった。該粒子の粒子構造を示すＴＥＭ像を図５に示した。得られた塗布試料を塗布試料３とした。ＥＰＡ２とＥＰＡ３は次の化合物を指す。ＥＰＡ２はＨ_２Ｃ＝Ｃ（ＣＨ_３）−ＣＯＯ−〔ＣＨ_２ＣＨ（ＣＨ_３）Ｏ 〕_１２−Ｈ：アクリルアミド＝２５：７５ 重合比の共重合体を、ＥＰＡ３はＨ_２Ｃ＝Ｃ（ＣＨ_３）−ＣＯＯ−（ＣＨ_２ＣＨ_２Ｏ）_２３−ＣＨ_３：アクリルアミド＝２５：７５ 重量比の重合体を指す。
【０１０６】
実施例４
第２熟成終了までを実施例１と同じにした。次にＨＮＯ_３ １Ｎ液を添加し、ｐＨ６．２とした後、３０℃に降温し、台錐型遠心分離器に乳剤を入れ、遠心分離し、上澄み液を除去した。その除去体積比率は、原乳剤の９３％であった。次にゼラチン溶液２を入れ、ｐＨ６．２とし、再分散し、乳剤を元の容器へ移液した。温度を６０℃とし、ＰＡＯ化合物としてＥＰＰ１ １０ｇ／リットル液を７ｍｌ添加し、後は実施例１と同じにした。乳剤３ｍｌをサンプリングし、生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。
ＳＡの９９％以上が、最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．１１μｍ、平均直径１．４１μｍ、平均アスペクト比約１２．８、Ｃ．Ｖ．値は０．０７５であった。後は実施例１と同じ態様で処理し、塗布試料４を得た。ここでＥＰＰ１はポリエチレンオキシドとポリプロピレンオキシドのブロックコポリマー（分子量約３２００）であり、ＢＡＳＦ社製の商品名プルロニック３１Ｒ１である。前記ＨＰ２に対応するＰＡＯ重合体である。
【０１０７】
実施例５
反応容器にゼラチン溶液５１〔Ｈ_２ Ｏ １．２リットル、ゼラチン１を１．７ｇ、ＫＢｒ １．２ｇ、ＨＮＯ_３ １Ｎ液でｐＨ３．０に調節〕を入れ、温度を３０℃に恒温しながら、Ａｇ−５１液（ＡｇＮＯ_３ １００ｇ／リットル）とＫＢｒ−５１液（ＫＢｒ ７２ｇ／リットル）５０ｍｌ／分で１分間添加し、核形成した。１分間攪拌した後、ＫＢｒ−２液（ＫＢｒ ３００ｇ／リットル）を１０ｍｌ添加し、１０分間で温度を６０℃に上げた。７分間、第１熟成した後、次にゼラチン溶液３（ゼラチン３を２５ｇ、Ｈ_２ Ｏ １３５ｍｌ含む）を添加し、温度を３７℃にし、ＮａＯＨ １Ｎ液でｐＨ９．５とした。ｐＨを９．５に保ちながら無水フタル酸溶液１（ドライアセトン中に無水フタル酸を１２重量％で溶解）を１５分間かけて一定流量で添加した。更に２０分間、ｐＨ９．５に保ちながら攪拌を続けた。次にＨＮＯ_３ ３Ｎ液でｐＨ４．０とし、乳剤を凝集沈降させ、上澄み液を除去した。純水を入れ、該凝集乳剤を水洗し、上澄み液を除去した。ＥＰＡ１を１ｇ含む純水１．３リットルを入れ、ＮａＯＨ液でｐＨ６．４とした。温度を６０℃に上げ、ＮａＢｒ液を入れ、ｐＢｒ１．６とした。
【０１０８】
Ａｇ−５２液（ＡｇＮＯ_３ １２０ｇ／リットル）とＸ−５２液（ＫＢｒ ９０ｇ／リットル）を用いて、ｐＢｒ１．６８に保ちながら３２分間の同時混合添加した。Ａｇ−５２液の初期流量は１２ｍｌ／分、直線流量加速量は０．６ｍｌ／分であった。１分間攪拌した後、乳剤３ｍｌをサンプリングし、生成粒子のレプリカのＴＥＭ像を観察した。その特性値は次の通りであった。ＳＡの９９％以上が最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．０９μｍ、平均直径１．３μｍ、平均アスペクト比約１４．４、Ｃ．Ｖ．値は０．０７２であった。
また、該乳剤をサンプリングし、遠心分離し、上澄み液をとりだした。温度を３０℃とし、上澄み液のｐＨを４．０とし、凝集させ、上澄み液を除去した。純水で３回水洗した。凝集物を乾燥させ、ゼラチン重量を測定した後、純水とＮａＯＨ液を加え、再分散させ、１重量％液とした。ゼラチン３の１重量％液を比較試料とし、前記フォルモル滴定法でフタル化率を求めた所、フタル化率９５％であった。従って、粒子成長時の分散媒の１００％が、フタル化率９５％、メチオニン含率３４μｍｏｌ／ｇ のゼラチンであった事になる。
次に乳剤の温度を３０℃に下げ、ｐＨ４．０にし、乳剤を凝集沈降させた。（上澄み液の除去→純水を入れリンスする）事を３回くり返した後、ゼラチン溶液３を添加した。後の工程は実施例１と同じにして塗布試料５を得た。
【０１０９】
実施例６
実施例１において、ゼラチン溶液１をゼラチン溶液４〔Ｈ_２ Ｏ １．２リットル、ゼラチン２を１．０ｇ、ＫＢｒ ０．２５ｇを含み、ＨＮＯ_３ 液とＮａＯＨ液でｐＨ５．０に調節〕に代え、Ｘ−１液をＸ−６１液（Ｈ_２ Ｏ １リットル、ＫＢｒ ４３．２ｇ、ゼラチン２を０．８ｇ含む）に代えた以外は実施例１と同じにした。この場合、核形成、熟成、成長時の分散媒の１００％が、フタル化率９５％、メチオニン含率３４μｍｏｌ／ｇ のゼラチンである。生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。ＳＡの９９％以上が最大隣接辺比率１〜１．２の六角平板粒子であり、平均厚さ０．０４６μｍ、平均直径２．１９μｍ、平均アスペクト比４７．６、Ｃ．Ｖ．値は０．０８５であった。
【０１１０】
実施例７
乳剤の水洗と再分散を次の態様にする以外は実施例６と同じにし、塗布試料７を得た。粒子形成後、温度を３０℃にし、台錐型遠心分離器に乳剤を入れ、遠心分離し、上澄み液を除去した。該除去量は母液量の９２％に相当した。純水を２Ｌ入れ、リンスした後、遠心分離し、母液の９２％に相当する上澄み液を除去した。ゼラチン３を５０ｇ含むゼラチン溶液を加え、ｐＨ６．４、ｐＢｒ２．８にし、乳剤を再分散させた。
【０１１１】
比較例１
欧州特許０５１４７４２Ａ１の実施例１に基づいて（１１１）平板粒子を調製した。粒子成長時の分散媒は１００重量％がメチオニン含率０μｍｏｌｇ、フタル化率０％であった。
生成粒子のレプリカのＴＥＭ像を観察した所、ｂ_２ ≧１．３２の粒子の投影面積の合計がＳＡの約３２％を占めた。該乳剤に凝集沈降剤を添加し、従来法に従って乳剤を水洗した。ゼラチン溶液３を添加し、ｐＨ６．４、ｐＢｒ２．８にし、乳剤を再分散させた。後は実施例１と同じにして塗布試料を作り、塗布試料２１とした。但し、分光増感色素と化学増感剤の添加は従来法通り、に添加した。生成粒子の粒子構造例を図６に示した。
【０１１２】
実施例１〜７と比較例１で得た塗布試料を５００ｎｍ以上の波長の光を通すマイナス青フィルターと光学ウェッジを通して０．１秒間露光した。次にＭＡＡ−１現像液〔Ｊｏｕｒｎａｌ ｏｆ Ｐｈｏｔｏｇｒａｐｈｉｃ Ｓｃｉｅｎｃｅ， ２３巻，２４９〜２５６（１９７５年）に記載されている〕で、２０℃で１０分間、現像した。常法に従って、停止、定着、水洗、乾燥処理をし、センシトメトリーを行なった。
得られた結果（感度／粒状性の相対値）を表２に示した。該相対値は高い程、写真性能が優れている事を表す。
感度は（かぶり＋０．２）の濃度を与える露光量の逆数で求めた。粒状性は試料を（かぶり＋０．２）の濃度を与える光量で一様に露光し、前述の現像処理を行なった後、マクミラン社刊，ザ・セオリー・オブ・ザ・フォトグラフィック プロセス，ｐ．６１９に記載の方法で測定した。
【０１１３】
実施例８
実施例７において、ゼラチン溶液４とＸ−６１液に用いるフタル化ゼラチンを表２に示した８１〜８６のゼラチンに置き代える以外は同じにした。８１〜８９のゼラチンのメチオニン含量とフタル化率は表３に示した通りである。８１〜８９のゼラチンを用いて調製したＡｇＸ乳剤の塗布試料をそれぞれ塗布試料８１〜８９とした。
塗布試料を該マイナス青フィルターと光学ウェッジを通して０．１秒間露光した。次にＭＡＡ−１現像液で、２０℃で１０分間現像した。センシトメトリーにより得られた結果〔（感度／粒状性）の相対値〕を表３に示した。図１のａ_１ 、好ましくはａ_２ 、より好ましくはａ_３ の領域のゼラチンを用いた時に、最も好ましい写真特性が得られた。
【０１１４】
【表２】

【０１１５】
【表３】

【０１１６】
実施例９
反応容器にゼラチン溶液４〔Ｈ_２ Ｏ １．２リットル、ゼラチン１を２０ｇ、ＮａＣｌを０．５ｇ含み、ＨＮＯ_３ １Ｎ液でｐＨ４．０に調節した〕を入れ、４０℃に保ち、攪拌しながらＡｇ−９１液（ＡｇＮＯ_３ ２００ｇ／リットル）とＸ−９１液（ＮａＣｌ ６９ｇ／リットル）を５０ｍｌ／分で１５秒間、同時混合添加した。１分間攪拌した後、Ｘ−９２液（１リットル中にＮａＣｌ ６ｇ、ＫＢｒ １５ｇを含む）を６０ｍｌ／分で２４秒間添加した。１分間攪拌した後、Ａｇ−９１液とＸ−９１液を５０ｍｌ／分で１分間、同時混合添加した。該核形成した後、次に温度を３７℃にし、ＮａＯＨ １Ｎ液を入れ、ｐＨ９．２とし、ｐＨを９．３に保ちながら無水フタル酸溶液１を１５分間かけて添加した。更に２０分間、９．３に保ちながら攪拌を続けた。ＨＮＯ_３ ３Ｎ液でｐＨ４．０とし、乳剤を凝集沈降させ、上澄み液を除去した。ＮａＣｌ ２．５ｇを含む純水１．３リットルを入れ、ＮａＯＨ液でｐＨ６．０にし、再分散した。ＨＮＯ_３ 液でｐＨ５．３とし、１２分間で７５℃に昇温した。１８分間熟成した後、ＮａＣｌ−１液（ＮａＣｌ １００ｇ／リットル）を１０ｍｌ添加し、更に５分間熟成した。ここで熟成は終了した。Ａｇ−９１液を７ｍｌ／分で添加し、銀電位を１４０ｍＶに調節した。
【０１１７】
銀電位を１４０ｍＶに保ちながら、Ａｇ−９１液とＸ−９１液を同時混合添加した。Ａｇ−９１液の初期流量は７ｍｌ／分で直線流量加速量は０．０５ｍｌ／分であり、総添加量は２９０ｍｌであった。次にＡｇ−９１液とＸ−９３液（１リットル中にＫＢｒ ２３ｇ、ＮａＣｌ ５９ｇを含む）を用いて、銀電位１２０ｍＶに保ちながら同時混合添加した。Ａｇ−９１液は８ｍｌ／分で７分間添加した。次にＡｇ−９１液とＸ−９４液（１リットル中にＫＢｒ ４５ｇ、ＮａＣｌ ５０ｇを含む）を用いて銀電位１２０ｍＶに保ちながら８ｍｌ／分で７分間添加した。１分間更に攪拌した後、温度を３０℃に降温し、ＨＮＯ_３ でｐＨ４．０とし、乳剤を凝集沈降させた。
【０１１８】
乳剤を純水で水洗した後、ゼラチン溶液を加え、ＮａＯＨ液でｐＨを６．１、ｐＣｌ ２．２とした。乳剤３ｍｌを ｓａｍｐｌｉｎｇ し、生成粒子のレプリカのＴＥＭ像を観察した。その特性値は次の通りであった。ＳＡの約９４％が（アスペクト比≧３）、主平面形状が直角平行四辺形、の（１００）平板粒子であり、平均厚さ０．１２μｍ、平均直径１．３μｍ、平均アスペクト比約１０．８、該平板粒子のＣ．Ｖ．値は０．２５であった。
乳剤温度を４０℃とし、増感色素２の０．３ｇ／リットル溶液を、前記多孔膜添加系を用いて、飽和吸着量の６５％だけ３秒間で添加した。１５分間攪拌した後、乳剤を次の容器に移液し、乳剤の温度を４０℃に保ちながら、多孔膜添加系を通してハイポを２．５×１０^−５モル／モルＡｇＸだけ添加し、次に塩化金酸を１０^−５モル／モルＡｇＸだけ添加した。５０℃に昇温し、１５分間熟成した後、かぶり防止剤２を３×１０^−３モル／モルＡｇＸだけ添加し、温度を４０℃にした。増粘剤、塗布助剤を加えてＴＡＣベース上に保護層と共に塗布し、乾燥し、塗布試料９とした。
【０１１９】
【化１０】

【０１２０】
実施例１０
核形成終了までを実施例９と同じにした。次に乳剤を台錐型遠心分離器に入れ、遠心分離し、上澄み液を除去した。該除去量は母液量の９５％であった。次にゼラチン溶液２を入れ、ｐＨ５．３とし、乳剤を再分散させ、乳剤を元の反応容器に戻した。この時の分散媒の９６．１重量％がフタル化率９６％、メチオニン含率３４μｍｏｌ／ｇ のゼラチンとなる。（ＮａＣｌ ２．６ｇ，Ｈ_２ Ｏ ２０ｍｌ）を含む液を入れ、１２分間で温度を７５℃に上げた。該昇温後は実施例９と同じ工程を通して塗布試料１０を得た。
生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。ＳＡの約９４％が（アスペクト比≧３）、主平面形状が直角平行四辺形の（１００）平板粒子であり、平均厚さ０．１３μｍ、平均直径１．２５μｍ、平均アスペクト比約９．６、該平板粒子のＣ．Ｖ．値は０．２６であった。
【０１２１】
比較例２
実施例９と次の工程以外は同じにして塗布試料２２を調製した。即ち、核形成終了後、ＮａＣｌ液（ＮａＣｌ １．６ｇ、Ｈ_２ Ｏ ２０ｍｌを含む）を入れ、ｐＨ５．３とし、７５℃への昇温工程に入る。また、結晶成長後の脱塩工程は、凝集沈降剤を添加して行なう、従来の凝集沈降水洗法で行なう。粒子成長時の分散媒の１００重量％がフタル化率０％、メチオニン含率３４μｍｏｌ／ｇ である。
生成粒子のレプリカのＴＥＭ像を観察した所、その特性値は次の通りであった。ＳＡの約９０％が（アスペクト比≧３）、主平面形状が直角平行四辺形の（１００）平板粒子であり、平均厚さ０．１９μｍ、平均直径１．０３μｍ、平均アスペクト比約５．４、該平板粒子のＣ．Ｖ．値は０．３０であった。
塗布試料９、１０、２２をマイナス青フィルターを通して１０^−２秒間の露光をし、現像した。センシトメトリーの結果、（感度／粒状性）の相対値は、試料９が１１２、試料１０が１１０、試料２２が１００であり、本発明法の効果が確認された。
【０１２２】
【発明の効果】
この様にして調製したＡｇＸ乳剤を支持体上に一層以上で塗布し、写真感光材料を製造した場合、かぶり濃度が低く、感度、粒状性の優れた写真感光材料が得られる。欧州特許５１４７４２Ａ号の態様に比べて、該ＰＡＯ重合体の最適添加量が約２０％以下になる為、他の写真的に有効な添加剤の吸着防害が少ないという利点も有する。
【図面の簡単な説明】
【図１】本発明に用いられるゼラチンのメチオニン含率（μｍｏｌ／ｇ） ｖｓ 、アミノ基の化学修飾（％）、の好ましい組み合せ範囲を示す。図１のａ _１ 領域の上限ラインは該修飾率＝１００％を示し、ａ _３ 領域の上限ラインは該修飾率＝９７％を示す。
【図２】（１００）平板粒子の結晶構造（転位線構造）の例
【図３】転位線の構造模式図
【図４】観察される種々のタイプの結晶構造（転位線構造）の例
【図５】実施例３で得られた平板粒子の結晶構造を示す。
【図６】比較例１で得られた平板粒子の結晶構造を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing silver halide grains (hereinafter referred to as “AgX”) useful in the field of photography and a silver halide emulsion.
[0002]
[Prior art]
When an AgX emulsion containing tabular grains having a large aspect ratio (diameter / thickness) is coated on a support and used for a photographic light-sensitive material, there are many advantages as follows. For example, the film thickness can be reduced to improve sharpness, the surface / volume ratio is large, so that a large amount of spectral sensitizing dye can be adsorbed, the light absorption rate is improved, and the surface / volume ratio is large, so that development processing is performed. Speedup, improvement of graininess by leveling the image, etc. Therefore, tabular grains have been widely used in many photographic materials. However, when the tabular grains were produced by a conventional method, there were the following disadvantages. Non-tabular grains are mixed and the grain size distribution is wide. That is, the particles were polydisperse both in terms of shape and size distribution. For this reason, when the particles are chemically sensitized or spectrally sensitized, there are disadvantages such as an aspect in which all of the particles are not optimally subjected to chemical sensitization or spectral sensitization, and the layering effect cannot be utilized.
[0003]
Many technical studies have been made to remedy this drawback. In the case of tabular grains containing parallel twin planes, the present inventors divided the production process into three processes of nucleation, ripening, and growth, and examined the optimum conditions for each process. That is, in the nucleation process, the twin plane formation probability is adjusted not to be too high and not too low. In the ripening process, tabular grains are left and other non-tabular grains are eliminated by utilizing the selective growth of tabular grains under a low supersaturation degree. In the growth process, a halogen ion (hereinafter referred to as "X") is used to achieve both selective growth of tabular grains and diffusion-controlled growth of the edge portion.⁻) By selecting the concentration and the degree of supersaturation to grow without expanding the size distribution, etc. For details, the description in the following literature can be referred to.
Cl⁻The details of the tabular grains having a content of 50 mol% or more are described in U.S. Pat. Nos. 5,176,992; 5,616,617; 4,44,003; 5,185,239; 5,183,732; 5,178,998; Is Br⁻With respect to the particles having a high content, refer to the descriptions in JP-A-63-151618, JP-A-63-11928, JP-A-2-28638, JP-A-1-131541, JP-A-2-838, JP-A-2-298935, and JP-A-3-121445. You can do it.
[0004]
On the other hand, the same problem also exists in the case of tabular grains having a principal plane of {100} faces when the grains are produced by a conventional method. In order to improve this, the manufacturing recipe is divided into three processes of nucleation, ripening, and growth, and a method of improving each process has been proposed. For details thereof, reference can be made to the descriptions in JP-A-5-281640, JP-A-5-313273, U.S. Pat.
[0005]
As a result of these studies, the monodispersity was significantly improved both in terms of particle shape and size distribution. However, the problem that the smaller the thickness of the tabular grains becomes, the wider the size distribution of the obtained grains has not been solved yet. In addition, there is a need for a method for producing the tabular grains having a lower fog density and more excellent sensitivity and granularity. Attempts have been made to improve the particle properties by changing the dispersion medium during the formation of the particles. For example, Kelly [Journal of Photographic Science, Vol. 6, 16-22 (1958)] discloses oxidized gelatin oxidized under various conditions and X.⁻AgNO in aqueous solution containing₃An aqueous solution was added to form AgBrI tabular grains. H₂O₂The use of oxidized gelatin which has been oxidized as described by Shepard and many other authors has been described. For details, see British Patent No. 245456, French Patent 768015, Gelatin in Photography-Monographs on the Theory of Photography from the Research Laboratory of the Eastman Kodak. No. 3. D. Van Nostrand Co. , New York. In addition, it has been confirmed that the methionine group is changed to methionine sulfoxide by the oxidation, which is described in Journal of Photographic Science, 16, 16, 68-69 (1968).
[0006]
Recently, it has been claimed to produce tabular grains having a thickness of 0.2 μm or less in an oxidized gelatin dispersion medium solution (methionine content <30 μmol / g). For example, JP-A-62-157024. When tabular grains are produced using the gelatin, thinner tabular grains are formed at all temperatures below 76 ° C. as compared to non-oxidized gelatin. However, the smaller the thickness of the particles, the wider the size distribution of the generated particles remains. EP 514 742 A discloses a method for forming AgBr tabular grains having {111} major planes in the presence of the oxidized gelatin and a polyalkylene compound to improve the above disadvantage. However, the main plane shape was a tabular grain distorted from a regular hexagon into an irregular shape, and the sensitivity, granularity, and fog density were not satisfactory.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing AgX tabular grains having a low fog density and excellent sensitivity and granularity and a silver halide emulsion.
[0008]
[Means for Solving the Problems]
The object of the present invention has been achieved by the following items.
(1) In a dispersion medium solution containing water and a dispersion medium, at least 75 to 100% of the total projected area of silver halide grains through a nucleation, ripening and growth process has a thickness of 0.02 to 0.3 μm. In a method for producing silver halide grains which are tabular grains having an aspect ratio (diameter / thickness) of 2 to 50, 30 to 100% by weight of the dispersion medium in the growing process has the following feature (a). A method for producing silver halide grains, characterized in that the silver halide grains are gelatin.
(A) -NH in the gelatin₂The relationship between the percentage of the number of chemically modified groups and the methionine content of the gelatin is shown in FIG.₁Area.
[0009]
(2) The dispersion medium solution is a polymer having a repeating unit of polyalkylene oxide, and has a molecular weight of 500 to 10.⁶HPAO [represented by general formula (1) -a) or (1) -b)] or PEOD [represented by any of -a) to -f) in general formula (2) Is contained in an amount of 0.001 g / L or more.
[0010]
Embedded image

[0011]
Where R⁰Is H, or a hydrocarbon having 1 to 10 carbon atoms having at least one polar group (e.g., -CH₂OH, -C₂H₅OH, -CH₂-O-CH₃), Preferably H. R represents an alkylene group having 3 to 10 carbon atoms.
n and m represent the average number of repeating units, and are values of 4 or more that satisfy the above molecular weight specification.
[0012]
Embedded image

[0013]
Here, LPU refers to a lipophilic group other than the HO-HPEOU- group and the HO-LPAOU- group, and is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, acyl group, Refers to an acylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, and an alicyclic group. Note that HPEOU and LPAOU have the same meanings as in the general formulas (1) -a) and (1) -b). LPU 'indicates H, an alkyl group having 1 to 20 carbon atoms.
[0014]
(3) The dispersion medium solution contains at least one kind of a polymer containing 1% by weight or more of the repeating unit of the monomer represented by the general formula (3) in an amount of 0.01 g / L or more, and the molecular weight of the polymer is 500-10⁶(1) The method for producing silver halide grains as described in (1) above.
[0015]
Embedded image

[0016]
Where R¹Represents H, a lower alkyl group having 1 to 4 carbon atoms;²Represents a monovalent substituent having 1 to 20 carbon atoms. R³Represents an alkylene group having 3 to 10 carbon atoms, and L represents a divalent linking group. n represents the average number of repeating units and is from 4 to 600.
[0017]
(4) The dispersion medium solution contains not less than 0.01 g / liter of a copolymer containing 1% by weight or more of at least two kinds of the monomers represented by the general formula (3) and the monomers represented by the general formula (4), respectively. And the molecular weight of the copolymer is 500 to 10⁶(1) The method for producing silver halide grains as described in (1) above.
General formula (4) CH₂= C (R⁴) -L '-(CH₂CH₂O)_m-R⁵
Where R⁴Represents H, a lower alkyl group having 1 to 4 carbon atoms;⁵Represents a monovalent substituent having 1 to 20 carbon atoms, and L ′ represents a divalent linking group. m represents the average number of repeating units and is from 4 to 600.
[0018]
(5) The dispersion medium solution contains at least one polymer containing 1% by weight or more of the repeating unit represented by the following general formula (5) and 1% by weight of the repeating unit represented by the general formula (6). At least one of the above polymers is contained in an amount of 0.01 g / L or more, and the molecular weight of each polymer is 500 to 10⁶(1) The method for producing silver halide grains as described in (1) above.
General formula (5)-(RO)_n−
General formula (6)-(CH₂CH₂O)_m−
In the formula, R represents an alkylene group having 3 to 10 carbon atoms.
n and m represent the average number of repeating units and are 4 or more that satisfy the molecular weight specification.
[0019]
(6) The polymer having a repeating unit represented by the general formula (5) is a vinyl polymer having a monomer represented by the following general formula (7)-(a) as a constituent component and a general formula (7)- (B) at least one kind of polymer selected from polymers containing polyurethane, and a polymer having a repeating unit represented by the general formula (6) is represented by the following general formula (7)-(c) And at least one polymer selected from substituted or unsubstituted polyethylene glycols, a vinyl polymer containing a monomer represented by the following formula, a polyurethane-containing polymer represented by formulas (7) to (d): (5) The method for producing silver halide grains according to the above (5).
General formula (7) -a) CH₂= C (R¹) -L- (R³-O)_n-R²
General formula (7) -b)
-[O- (RO)_n]_x-[O-R¹¹-O]_y-[CONH-R¹²-NHCO]_Z−
General formula (7) -c) CH₂= C (R⁴) -L '-(CH₂CH₂O)_m-R⁵
General formula (7) -d)
-[O- (CH₂CH₂O)_m]_{X '}-[OR^Thirteen-O]_{y '}-[CONH-R¹⁴-NHCO]_{Z '}−
In the formula, n and m represent the average number of repeating units, and are 4 to 600. R¹, R⁴Represents H or a lower alkyl group having 1 to 4 carbon atoms. R², R⁵Represents H or a monovalent substituent having 1 to 20 carbon atoms. L and L 'represent a divalent linking group. R¹¹, R¹², R^Thirteen, R¹⁴Represents a divalent linking group, and represents an alkylene group having 1 to 20 carbon atoms, a phenylene group having 6 to 20 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms. x, y, z, x ', y', z 'represent the weight percentage of each component, x, x' is 1-70, y, y 'is 1-70, z, z' is 20-70. Represent. Here, x + y + z = 100 and x ′ + y ′ + z ′ = 100. R represents an alkylene group having 3 to 10 carbon atoms.
[0020]
(7) The principal plane of the tabular grains is a {100} plane or a {111} plane, and the coefficient of variation (standard deviation / average diameter) of the diameter distribution of the grains is 0 to 0.3. 7. The method for producing silver halide grains according to the above 1-6.
(8) In a silver halide emulsion having at least a dispersion medium and silver halide grains, 75 to 100% of the total projected area of the silver halide grains has a thickness of 0.02 to 0.3 μm and an aspect ratio (diameter / diameter / Tabular grains having a thickness of 2 to 50, the coefficient of variation (standard deviation / average diameter) of the diameter distribution of the grains being 0 to 0.3, and 30 to 100% by weight of the dispersion medium being (chemically modified). -NH₂The relationship between the% of the base and the methionine content is shown in FIG.₁Silver halide emulsion).
[0021]
Other preferred embodiments of the present invention are as follows.
(9) In a silver halide emulsion having at least a silver sensitizing grain to which a spectral sensitizing dye has been adsorbed and a dispersion medium, 75 to 100% of the projected area of the silver halide grain has an aspect ratio of 2 to 50 and a thickness of Are tabular grains having a diameter of 0.02 to 0.3 μm, the coefficient of variation of the diameter distribution is 0 to 0.3, and the coefficient of variation of the adsorption coverage of the spectral sensitizing dye is 0 to 0.3. Silver halide emulsion.
(10) The tabular grains are at least 10^-7selenium sensitization at mol / mol Ag or more, the Se content of the tabular grains is proportional to the surface area of the tabular grains, and the coefficient of variation of the inter-particle variation of the proportionality constant is 0 to 0. 3. The silver halide emulsion as described in (9) above, wherein
(11) the tabular grains are at least 10^-7mol / mol Ag or more is gold sensitized, and the gold content of the tabular grains is proportional to the surface area of the tabular grains. 3. The silver halide emulsion as described in (9) or (10) above, wherein
[0022]
Hereinafter, the present invention will be described in more detail.
A. Tabular grains
The tabular grains include {100} plane tabular grains (hereinafter referred to as “(100) tabular grains”) and {111} plane tabular grains (hereinafter referred to as “(111) tabular grains”). I can list them.
The tabular grains have a thickness of 0.02 to 0.3 μm, preferably 0.02 to 0.15 μm, more preferably 0.03 to 0.10 μm, and most preferably 0.04 to 0.08 μm. The aspect ratio (diameter / thickness) is 2 to 50, preferably 3 to 30. The coefficient of variation of the diameter distribution (standard deviation of distribution / average diameter) (hereinafter referred to as “CV value”) is preferably 0 to 0.3, more preferably 0 to 0.2, and more preferably 0 to 0.1. Is more preferable, and 0 to 0.08 is most preferable. Here, the diameter refers to the diameter of a circle having an area equal to the projected area of the grains, and the thickness refers to the distance between two main planes of the tabular grains. The diameter of the particles is preferably 0.1 μm or more, more preferably 0.2 to 10 μm. The tabular grains account for 75 to 100%, preferably 90 to 100%, more preferably 97 to 100% of the total projected area of the AgX grains. The coefficient of variation (standard deviation of distribution / average thickness) of the thickness distribution of the tabular grains is preferably 0 to 0.3, more preferably 0 to 0.2, and still more preferably 0 to 0.1.
[0023]
The tabular grains are produced through at least the steps of nucleation → ripening → growth. The nuclei of the finally obtained tabular grains are substantially formed during the nucleation process. Here, “substantially” refers to a number, preferably 75 to 100%, more preferably 95 to 100%.
When the modified gelatin is used in the process of nucleation and ripening, the pH of the reaction solution in those processes is preferably a pH equal to or higher than the isoelectric point of the modified gelatin, and more preferably (isoelectric point pH + 0.2) to pH 10. , (Isoelectric point pH + 0.4) to pH7 are more preferable. AgNO added during nucleation₃Is preferably 1 g or more per liter of the reaction solution, more preferably 1.8 g or more, and even more preferably 3 to 30 g. Nucleation is based on Ag in the reaction solution.⁺Liquid and X⁻It is more preferable to carry out the method by the simultaneous mixing and addition of liquids or the method of adding a plurality of alternate single jets two to 1,000 times. Next, the (100) tabular grains will be described in order.
[0024]
A-1. (100) Tabular grains
1. Particle structure
When tabular grains whose main planes are {100} planes are classified by shape, the following six can be mentioned. (1) Particles having a main plane shape of a right-angled parallelogram and an adjacent side ratio (length of long side / length of short side) of 1 to 10, preferably 1 to 3, within one tabular grain. (1) Particles in which one or more, preferably 1 to 3, of the four corners of the right-angled parallelogram are non-equivalently missing. That is, [(area of the largest missing part / area of the smallest missing part) = a₁Are particles of 2 to ∞), (3) particles in which the four corners are equivalently missing (the a₁(4) particles having a (111) plane in the area of 5 to 100%, preferably 20 to 100% of the area of the missing portion, (5) of the four sides constituting the main plane (6) One or more, preferably 1 to 3, of the four corners of the right-angled parallelogram are missing in the right-angled parallelogram. particle.
2. Nucleation
The core of the (100) tabular grain is produced by the following method. (1) In a low protective colloid solution, a silver salt solution and a halogen salt solution (hereinafter referred to as “X⁻Salt solution) to form nuclei. There is a thought that crystal defects are formed due to coagulation. (2) Plate nucleation by lattice constant mismatch. For example, a) a nucleus having one or more, preferably one to four, more preferably two to three halogen composition gap planes is formed. Specifically, (AgX₁｜ AgX₂), X₁And X₂The halogen composition of Cl⁻Content, or Br⁻Content, or I⁻The content differs by 10 to 100 mol%, preferably 30 to 100 mol%, more preferably 60 to 100 mol%. Here (AgX₁｜ AgX₂) Is AgX₁After nucleation, AgX₂Refers to an embodiment in which a layer is laminated on the surface of the core. More specifically, X added during nucleation⁻This means that the halogen composition of the salt solution is discontinuously changed at the gap surface in accordance with the above-mentioned rules. The gap is AgX₁In the nucleus, X₂ ⁻It can also be formed by adding a salt solution to generate a halogen conversion.
[0025]
The plate nucleus having two gap faces is (AgX₁｜ AgX₂｜ AgX₃) Can be written. B) Sulfur, selenium, tellurium, SCN between adjacent phases of the gap to promote the formation of defects due to the lattice irregularity.⁻, SeCN⁻, TeCN⁻, CN⁻, (Ag⁺And a complex of the metal ion (the ligand is X⁻Ligand, CN⁻Ligand, isocyano, nitrosyl, thionitrosyl, amine, hydroxyl), preferably at least 0.1% to 100% by mole difference, more preferably 1 to 100% by mole difference, An embodiment in which the difference is preferably 10 to 100 mol% can be mentioned. Ag⁺Representative examples of metal ions other than the above include metal ions of Group VIII of the periodic table, and metal ions of Cu, Zn, Cd, In, Sn, Au, Hg, Pb, Cr, and Mn.
[0026]
c) In addition, there can be mentioned an embodiment in which the defect is formed only by the impurity ion content gap. For details of specific examples of the compound of these impurity ions and the method of doping the AgX phase, Research Disclosure, Vol. 307, Item 307105, November, 1989, U.S. Pat. 4847191, 4933272, 4981781, 5024931, JP-A-4-305644, 4-321024, 1-183647, 2-20853, 1-288541, 3-118536. Can be.
[0027]
In the present invention, the nucleation method of the above 2- (2), preferably 2- (2), can be preferably used, and the halogen conversion method can be more preferably used. The tabular grains are formed because there are defects which promote growth in the edge direction of the tabular grains. The defect is referred to as a screw dislocation defect in the present invention. When a large number of the defects are formed in one particle, growth in three-dimensional directions occurs, and the generated particle becomes thick. When the defect formation probability is gradually increased from zero, tabular grains having a side ratio of 1 to 2 are formed first, so that the grains promote the growth in the [110] direction or in the -25 ° to + 25 ° direction. It is considered that there is one screw dislocation defect having a vector. Increasing the probability further increases the number of tabular grains produced, and further increasing the proportion increases the proportion of grains having a low aspect ratio. This is considered to be because the defect contains two or more defects per particle and has a growth acceleration vector in the thickness direction. Therefore, the probability may be increased as long as the mixing ratio of thick particles is allowed.
[0028]
The gap is (AgX₁｜ AgX₂) In addition to the method of forming with composition, (AgX₁｜ AgX₁₂｜ AgX₂) It may be formed by nucleation. In this case AgX₁₂Is Ag₁X₁And AgX₂Is an intermediate layer having a halogen composition between the two. AgX₁And AgX₂When the halogen composition difference is increased, the number of nuclei of tabular grains increases, but the ratio of the number of nuclei of thick grains also increases. The addition of the intermediate layer increases the number of tabular grain nuclei generated, but has the effect of suppressing the rate of formation of thick grain nuclei. In this case, (AgX₁｜ AgX₁₂) And (AgX₁₂｜ AgX₂) Is (AgX₁｜ AgX₂) Is preferably 10 to 90%, more preferably 30 to 70% of the gap amount. The number of the intermediate layers is 1 to 4, preferably 1. The intermediate layer can be provided on one or more of the gap surfaces even in the embodiment having two or more gap surfaces.
[0029]
3. Aging
Of the nuclei generated by nucleation, preferably 30 to 100%, more preferably 60 to 100%, of non-tabular grain nuclei are eliminated by ripening in the ripening process to increase the projected area ratio of tabular grains. Specifically, the reaction solution is matured by increasing the solubility of AgX to 1.1 times or more, preferably 1.5 to 30 times. The following method can be mentioned as a method for increasing the solubility. (1) The temperature is increased by 5 ° C. or more, preferably 10 to 60 ° C. (2) X⁻Add salt or silver salt. (3) Add AgX solvent. (4) A combination method of two or more of the above (1) to (3). (Cl in the reaction solution⁻Concentration / X⁻When the concentration is 0.9 to 1.0, 30% or more of the nuclei are first eliminated by the temperature increase, and then Cl is added.⁻More preferably, a salt is added to increase the solubility of AgX to 1.1 times or more, preferably 1.3 to 10 times, so as to eliminate 80 to 100%, preferably 97 to 100% of the remaining nuclei.
After disappearance, the excess Cl⁻The concentration is AgNO₃It can be reduced by adding a liquid, or can be reduced by desalting by a conventionally known emulsion desalting method. AgNO₃The addition rate of the liquid can be selected from the optimum addition rate, and it is preferable to add the solution at a rate that does not generate new nuclei.
[0030]
When the nuclei on which the halogen composition gap surfaces are formed are aged to eliminate the non-tabular grain nuclei, different types of halogen ions accumulate in the tabular grains growing at that time. At this time, defects such as screw dislocations are further incorporated into the tabular grains, and growth promoting defects having a growth vector component in a direction perpendicular to the main plane are incorporated. Therefore, the tabular grains become thicker as they grow. In order to prevent this, different types of halogen ions may be diluted with host halide ions. To give a specific example, (Inner core | Outer core) is (AgX₁｜ AgX₂) In the case of nuclei, foreign ions X released during ripening₂Ag to dilute⁺And X₁ ⁻A method of ripening while adding, the structure of the core (AgX₁｜ AgX₂｜ AgX₁And X having a particle diameter of 0.01 to 0.15 μm.₁A method of adding fine particles having a high composition ratio, and a method of using two or more of them in combination can be exemplified. By this dilution, the number of screw dislocation defects newly formed when the non-tabular grain nuclei are annihilated is preferably 0 to 0.3, more preferably 0 to 0.2 of the number of existing defects.
[0031]
A-2. (111) Tabular grains
1. Particle structure
When classified according to the shape of the main plane of the (111) tabular grains, the following two can be cited. (1) Hexagonal tabular grains whose peripheral shape around a main plane is substantially hexagonal. Here, “substantially” means that the maximum adjacent side ratio of the hexagon [the length of the longest side / the length of the shortest side in one hexagon] is 1 to 2, preferably 1 to 1.5. It refers to an embodiment that is preferably 1 to 1.2. (2) Triangular tabular grains having a substantially triangular shape around the main plane. Here, “substantially” refers to an aspect in which the adjacent side ratio is greater than 2. (3) A mode in which the corners of the particles (1) and (2) are rounded. The ratio (b₁) Is 0 to 0.5 and 0.5 <b₁<1.0 particles can be mentioned. b₁The value indicates the ratio of the length of the straight portion of the side to the length between the intersections formed by extending the straight portion of the surrounding side. (4) The particles of (1) to (3), wherein [the area of the {111} face of the edge face / the total area of the edge face] is 0 to 1.0; Area / total area of edge surface] of 0 to 1.0. Particles having [area of {111} of edge surface / area of {100} surface of edge surface] of 0.01 to 100.
[0032]
In the embodiment of the hexagonal tabular grain and the triangular tabular grain having the six sides described above, the length of the longest side / the shortest side of every other three sides = b₂Is preferably 1 to 1.3, more preferably 1 to 1.2, and most preferably 1 to 1.1. It is preferable that the total projected area of the grains accounts for 80% or more, preferably 90% or more, more preferably 97 to 100% of the total projected area of all AgX grains.
The number of twin planes parallel to the main plane is 2 to 4, preferably 2 to 3, and more preferably 2. Usually, two grains are the hexagonal tabular grains and three grains are the triangular tabular grains, but there is also an embodiment in which two grains are triangular tabular grains. In particular, it appears when a thin tabular grain of 0.1 μm or less is grown under a low supersaturation degree. The edge surface has a concave corner portion and a convex corner portion, but the concave corner portion grows faster because of a larger number of atomic bonds. In the case of thin tabular grains, since (thickness / twin plane spacing) is small, it is often (area of the concave corner portion / area of the convex corner portion).
[0033]
It is considered that when the particles are grown with low supersaturation, the side of (area of the concave surface> area of the convex surface) grows faster. It is considered that the growth rate of the edge portion of the grain having three parallel twin planes is (the edge portion having two reentrant angles> the edge portion having one reentrant angle). This is because the edge portion having two reentrant corners has more (the number of active growth points / unit area) and the relationship of (reentrant angle area> projection angle area) holds.
(Thickness of tabular grains / interval between twin planes) or (thickness of tabular grains / interval between outermost twin planes) is 1.1 or more, preferably 1.5 to 100, more preferably 2 to 50. It is. The outermost twin plane refers to the twin plane closest to the main plane. In the present invention, the hexagonal tabular grains or grains having rounded corners (0.5 <b₁<1.0) is preferable, the adjacent side ratio is more preferably 1 to 1.5, and still more preferably 1 to 1.2. The grains are hereinafter referred to as “regular hexagonal tabular grains”.
[0034]
2. Nucleation
The temperature at the time of nucleation is preferably 60 ° C or less, more preferably 10 to 50 ° C. The concentration of the dispersion medium is preferably 0.01 to 5% by weight, more preferably 0.01 to 1% by weight, and still more preferably 0.03 to 0.6% by weight. X⁻Salt concentration is 10^−0.8-10^-3Mol / l is preferred, and 10^−1.2-10^-2.7Mol / l is more preferred, and 10^-1.6-10^-2.7Mole / liter is more preferred. Ag to be added⁺Liquid and / or X⁻An embodiment in which the liquid contains a dispersion medium is preferred, and the concentration is preferably 0.01 to 1% by weight, more preferably 0.03 to 0.6% by weight. The molecular weight of the dispersion medium is preferably 3000 to 200,000, more preferably 3000 to 100,000. The pH of the reaction solution is preferably from 1 to 11, and more preferably from 2 to 6. The dispersion medium is preferably gelatin, more preferably alkali-treated gelatin, and more preferably modified gelatin described below.
In order to accelerate the ripening in the next ripening step and to further increase the tabular grain ratio, it is preferable to form micronuclei under conditions of low AgX solubility. That is, low X⁻Concentration and low temperature are preferred. X⁻The decrease in the twin plane formation probability due to the decrease in the concentration may be compensated by decreasing the concentration of the dispersion medium. In addition, the lower the pH, the lower the AgX solubility of the dispersion medium, which is usually preferable.
30% or more, preferably 60 to 100%, more preferably 80 to 100% of the amount of silver salt added at the time of nucleation is X⁻It is preferable to add the salt and the salt at the same time.
[0035]
3. Aging
Of the nuclei formed by nucleation, preferably 75 to 100%, more preferably 90 to 100%, and even more preferably 100%, of non-tabular grain nuclei are eliminated during this ripening process, and the projected area ratio of tabular grains Enhance. Specifically, aging is performed by increasing the solubility of the reaction solution to 1.1 times or more, preferably 1.5 to 30 times. As a method for increasing the solubility, the method described in the above-mentioned item A-3 can be mentioned. The ripening proceeds more rapidly as the concentration of the dispersion medium during ripening is lower and the pH is lower. It is understood that this is because the adsorptive power of the dispersion medium to the AgX particles becomes weak, the growth alienation factor of the tabular grains is removed, and the dissolution of the non-tabular grains is promoted. Regarding the concentration of the dispersion medium during aging, the molecular weight of the dispersion medium, the pH of the reaction solution, and the type of the dispersion medium, the description in the above section 2 can be referred to. X⁻Salt concentration is 10^−0.8-10^−2.5Mol / l is preferred, and 10^−1.2-10^-2Mole / liter is more preferred.
[0036]
B. Tabular grain growth conditions
In the present invention, 30 to 100% by weight, preferably 60 to 100% by weight, more preferably 75 to 98% by weight, and most preferably 80 to 96% by weight of the dispersion medium in the dispersion medium solution in the growth process is chemically modified. -NH₂The relationship between the% of the base and the methionine content is shown in FIG.₁, Preferably a₂And more preferably a₃Gelatin in the region of The following method can be cited as a method for realizing this embodiment.
[0037]
(1) Nucleation and ripening are performed using a dispersing medium other than the modified gelatin (hereinafter referred to as “unmodified medium”), and before growth, 10 to 99.7% by weight of the dispersing medium is removed. Adding the modified gelatin to the mixture. (2) A method in which nucleation is performed using an unmodified medium, 10 to 99.5% by weight of the dispersion medium is removed after nucleation, and the modified gelatin is newly added. (3) A method in which nucleation is carried out at a low concentration of an unmodified medium, and the modified gelatin is added after nucleation. (4) A method in which nucleation and ripening are performed at a low concentration of a non-modified medium, and the modified gelatin is added after ripening. (5) A method in which nucleation and ripening are performed under the concentration of the modified gelatin. The modified gelatin can be further added after nucleation or ripening. (6) A method in which the process is performed in the presence of unmodified gelatin until after nucleation or after ripening, and then the gelatin is modified with a modifier described below to increase the ratio of the modified gelatin. (7) Until the nucleation or ripening is carried out in the presence of the unmodified gelatin, then the unmodified gelatin is added, and the mixture is homogenized and mixed. How to increase the ratio of modified gelatin.
[0038]
The following method can be used as a method for removing the dispersion medium. 1) A method of centrifuging an AgX emulsion and removing a supernatant. 2) A method of removing by an ultrafiltration method using an ultrafiltration membrane. 3) A method of adding a coagulating sedimentation agent and washing by settling, or a method used in combination with a centrifugation method.
The removal rate of the dispersion medium is preferably 30 to 99.5% by weight, more preferably 60 to 99%, and most preferably 90 to 99%.
The methods (1) to (4), (6) and (7) can be more preferably used. The low concentration of (3) and (4) indicates 0.01 to 1% by weight, preferably 0.03 to 0.6% by weight, and more preferably 0.03 to 0.3% by weight. Further, the amount of the modified gelatin to be added later is an amount necessary to achieve the embodiment of the present invention.
[0039]
In order to grow the tabular grains without increasing the thickness and without expanding the size distribution, it is necessary to precisely control the adsorptivity of the dispersion medium to the AgX particles. H in aqueous gelatin solution₂O₂Was added to oxidize the gelatin,₂O₂(Number of methionine sulfoxide groups / number of methionine groups) = C₁Increase. C₁The adsorption power of gelatin to the AgX particles decreases with the increase in the amount of gelatin. The C₁When various types of gelatin having different values are used and (111) tabular grains are grown under the same conditions in an aqueous solution thereof, the obtained tabular grains have C₁As the value increases, it becomes thinner, but at the same time the size distribution broadens. This phenomenon can be understood as follows.
[0040]
Since the oxidation did not change the lysine group, aspartic acid group or glutamic acid group at all, this change₁Attributable to value changes. That is, since the strong adsorption of the methionine group disappears, the rate of growth of the edge surface of the tabular grain changes from the rate of desorption of the methionine group to the rate of reaction of the edge surface. Since the growth active site of the (111) tabular grain is the reentrant corner of the edge, the probability that a single tabular grain forms a growth nucleus on the reentrant corner is proportional to the edge length around the tabular grain. . Since the edge length (2πd) is proportional to the diameter (d), the growth nucleation probability is proportional to d. When the growth nucleation process is growth-determined, the growth rate becomes (larger particles> small particles), and the size distribution expands with growth.
[0041]
However, even when methionine is added to the oxidized gelatin by only 100 (μmol / g gelatin) to grow tabular grains, the thin tabular grains are formed. Therefore, the methionine group alone in gelatin does not alone retain strong adsorption power. Amino groups of gelatin are phthalated with phthalic anhydride to prepare gelatins having various phthalation rates. Next, when the same seed crystal tabular grains are grown in the dispersion medium under the same conditions, the tabular grains generated become thinner with an increase in the phthalation rate, but the size distribution is not so widened. Therefore, in order to prepare thin tabular grains having a uniform size distribution, it is necessary to select an optimal combination of the methionine group content and the amino group content of gelatin. The selection of this optimal value has been made for the first time by the present invention. 1-phenyl-5-mercaptotetrazole strongly adsorbs to AgX particles, but mercapto groups alone or tetrazole groups alone do not show so strong adsorption. The above phenomenon can be considered similarly. That is, the strong adsorption of gelatin to AgX particles is due to the methionine group in the gelatin molecule and -NH.₂It is thought to be caused by the concert effect of the group. When grown on the oxidized gelatin, distorted tabular grains having a hexagonal shape are formed.₁Region, preferably a₂When gelatin in the region (1) is used, regular hexagonal tabular grains are formed.
[0042]
Another major factor controlling the adsorption power of the dispersion medium to AgX particles is temperature. Even with the same dispersion medium, as the temperature is lowered, the frequency of desorption of the adsorbing group is reduced, and the particle growth becomes more desorption-controlled. In this case, all surfaces of the tabular grains approach more uniform growth. Therefore, as the temperature is increased, the rate of desorption is eliminated, the selective growth of the edge is enhanced, and tabular grains having a higher aspect ratio are obtained. When the same tabular grains are grown at various temperatures of 30 to 80 ° C. using various dispersing media, the change in the aspect ratio of the resulting tabular grains has a high methionine content and a high free amino group content. Higher gelatin is larger. In the embodiment of the present invention, monodisperse tabular grains having a small aspect ratio and a high aspect ratio over a wide temperature range can be obtained. Further, since an appropriate adsorption force to the AgX particles is maintained, generation of fog is suppressed, and particles having a high (sensitivity / fogging) ratio can be obtained. The growth temperature is preferably 30C or higher, more preferably 40 to 90C. The most preferred temperature can be selected and used.
Another major factor controlling the adsorption power of the dispersion medium to AgX particles is pH. Using oxidized gelatin having a methionine content of zero, dispersion medium solutions of various pHs are prepared. When the same (111) tabular seed crystal is put into each solution and grown, the mixing ratio of thick tabular grains increases as the pH increases. It becomes remarkable at pH 8 or more, particularly at pH 9 or more. At this time, since methionine sulfoxide does not change, it indicates that methionine alone is not the cause of the formation of thick plate particles. On the other hand, when the modified gelatin of the present invention is used, the pH dependency is small, and no thick particles are mixed even at pH 9 to 10. That is, when the growth pH is 6 to 11, preferably 6 to 10, the advantage becomes larger.
On the other hand, in the case of (100) tabular grains, thinner tabular grains can be obtained as the ripening and growth conditions are set to a higher pH. The relationships and reasons are summarized in Table 1. Here, Gel. Refers to gelatin.
[0043]
[Table 1]

[0044]
The growth of these tabular grains is preferably performed by selecting the most preferable degree of supersaturation according to the purpose. When the critical degree of supersaturation is 100 and the degree of supersaturation when no solute is added is 0, 5-90 is preferable, and 10-80 is more preferable. Here, the critical supersaturation degree is defined as AgNO₃Aqueous solution and X⁻When the salt aqueous solution is added at the same time, it indicates the degree of supersaturation when a new nucleus is generated when the salt solution is added at a higher rate. When the degree of supersaturation is increased, the obtained tabular grains are more monodispersed, but also grow in the thickness direction and have a lower aspect ratio. Lowering the degree of supersaturation increases the aspect ratio, but broadens the size distribution.
The concentration of the dispersion medium during growth is preferably 0.1 to 7% by weight, more preferably 0.3 to 3% by weight. The molecular weight is 3000 to 200,000, preferably 6000 to 120,000. The pH of the solution is preferably a pH equal to or higher than the isoelectric point of the modified gelatin, more preferably (isoelectric point pH + 0.2) to pH 11, and further preferably (isoelectric point pH + 0.4) to pH10. When tabular grains are grown under the same conditions, the lower the pH, the lower the gelatin concentration, and the lower the molecular weight, the higher the aspect ratio of the resulting tabular grains. The most preferable combination can be selected and used according to the purpose.
[0045]
X in the reaction solution during ripening and growth of (111) tabular grains⁻Is preferably in the octahedral particle forming region. Here, the octahedral particle generation region is defined as X⁻Ag while keeping the concentration condition⁺And X⁻Is added at the same time to form AgX particles, a concentration range in which 70 to 100%, preferably 90 to 100% of the particle surface forms {111} plane particles. Usually, the X⁻The concentration is 10^-0.5-10^−2.5Mol / l is preferred, and 10^-1-10^-2Mole / liter is more preferred.
This feature is found not only in (111) tabular grains but also in (100) tabular grains. Therefore, it can be preferably used also for the (100) tabular grains. (100) X in the reaction solution during nucleation, ripening, and growth of tabular grains⁻The concentration is preferably in a cubic particle generation region. Here, the cubic particle generation region is defined as X⁻Ag while keeping the concentration condition⁺And X⁻Is added at the same time to form AgX particles, a concentration range in which 70 to 100%, preferably 90 to 100% of the particle surface forms {100} plane particles. Usually, the X⁻, And Ag⁺The concentration is 10^−1.5Mol / l or less, preferably 10^-2More preferably, it is not more than mol / liter.
With respect to the other details of the tabular grains, the description of the literature described in the section of the “prior art” and JP-A-3-288143, JP-A-3-212639, JP-A-3-116133, JP-A-2-301742, JP-A-2-34, JP-A-6-59360, Japanese Patent Application No. 6-47991, JP-A-5-248218, JP-A-5-264059, JP-A-5-96250, and descriptions of the following documents can be referred to. .
[0046]
C. Modified gelatin
-NH in gelatin₂Examples of the group include an amino group of a terminal group of a gelatin molecule, a lysine group, a hydroxylysine group, a histidine group, an amino group of an arginine group, and, if the arginine group is converted to an ornithine group, the amino group can be mentioned. . Further, impurity groups such as adenine and guanine groups can also be mentioned. -NH₂Chemical modification of a group means adding a reaction reagent to gelatin and reacting with the amino group to form a covalent bond or deamination. That is, a primary amino group (—NH₂) To a secondary amino group (—NH—), a tertiary amino group, or a deaminated product.
[0047]
Specifically, for example, acid anhydrides (maleic anhydride, o-phthalic anhydride, succinic anhydride, isatoic anhydride, benzoic anhydride, etc.), acid halides (R-COX, R-SO₂X, RO-COX, Phenyl-COCl, etc.), a compound having an aldehyde group (R-CHO, etc.), a compound having an epoxy group, a deaminating agent (HNO₂, Deaminese, etc.), active ester compounds (sulfonic acid esters, p-nitrophenyl acetate, isopropenyl acetate, methyl o-chlorobenzoate, p-nitrophenyl benzoate, etc.), isocyanate compounds (Aryl isocyanate, etc.), active halogen compounds, for example [Aryl halide (benzyl bromide, biphenyl-halomethanes, benzoyl halomethane, phenyl benzoylhalo-methane, 1-Fluoro-2,4-dinitro-a-hate, β-fluoro-2,4-dinitro-athene-a, py imidine, pyridazine, pyrazine, pyridazone, quinoxaline, quinazoline, phthalazine, benzoxazole, benzothiazole, chlorine derivatives of benzoimidazole)],
Carbamoylation agent (cyanate, nitrourea, etc.), compounds having an acrylic type active double bond group (maleimide, acrylamine, acrylamide, acrylonitrile, methylmethaacrylate, vinyl sulphone, vinylsulphonate ester, sulphonamide, styrene and vinylpyridine, allylamine, butadiene, isoprene, chloroprene ), Sultones (butane sultone, propane sultone), Guanidine agent (o-methylisourea, etc.), carboxylazide, etc. For example, it can be achieved by reacting.
[0048]
In this case, the reagent which also reacts with the -OH group or -COOH group of gelatin and forms a covalent bond is mainly composed of -NH group of gelatin.₂Reagents that react with groups are more preferred. It mainly means 60% or more, preferably 80 to 100%, more preferably 95 to 100%. Furthermore, an embodiment in which the reaction product does not substantially contain (a group in which oxygen of an ether group or a ketone group replaces a chalcogen atom, for example, -S- or thione group) is more preferable. Here, “substantially not contained” refers to preferably 10% or less, more preferably 0 to 3% of the number of the chemically modified groups. Accordingly, among the above, acid anhydrides, sultones, compounds having an active double bond group, carbamoylating agents, active halogen compounds, isocyanate compounds, active ester compounds, compounds having aldehydes, and deamino groups are more preferred. An embodiment in which cross-linking between gelatin molecules is substantially impossible by the chemical modification is more preferable. Here, "substantially impossible" means that the content of the chemically modified group is preferably 10% or less, more preferably 0 to 3%.
[0049]
For details of the chemical modifying agent and the method of chemically modifying gelatin, see the below-mentioned documents, JP-A-4-226449, JP-A-50-3329, U.S. Pat. Nos. 2,525,753, 2,614,928, 2,614,929 and 2,614,929. No. 2763639, No. 2594293, No. 3132945, edited by Yoshiko Abiko, Nika and Gelatin, Chapter II, Japan Nika and Gelatin Industry Association (1987), edited by Ward et al., The Science and Technology of Gelatin, Chapter 7, Academic. Press (1977) can be referred to.
-NH of the modified gelatin₂The chemical modification% of a group can be determined as follows. Gelatin without the modification and gelatin with the modification are prepared, and -NH₂Base e₁, E₂Asking. Chemical modification% is 100 × (e₁-E₂) / E₁I can ask more. The e₁And e₂Is obtained by -NH₂Examples of the method include a method using an infrared absorption intensity based on a group, an NMR signal intensity of the proton, a color reaction, and a fluorescence reaction. For details, see the descriptions in Analytical Chemistry Handbook, Organic Edition-2, Maruzen (1991). You can refer to it. Other examples include a change in the titration curve of gelatin and a quantitative method such as a formol titration method, and the details can be referred to the description of The Science and Technology of Gelatin, Chapter 15, Academic Press (1977). .
[0050]
In addition, a method in which a mixture of glutaraldehyde and Britton-Robinson high pH buffer is added to a gelatin solution having a specified concentration, color is developed, the spectral absorption intensity around 450 nm is measured, and colorimetric determination is performed [Photographic Gelatin II, p. 297 to 315, Academic Press (1976) can be referred to].
The methionine content of the gelatin can be determined by completely decomposing the gelatin into amino acids by an alkaline hydrolysis method, analyzing the resultant with an amino acid analyzer, and determining the methionine content relative to the glycine content. For details, the description of Japanese Patent Application No. 6-102485 can be referred to. The methionine content of the gelatin can be adjusted by adding an oxidizing agent to the aqueous gelatin solution and oxidizing the -S- group of methionine to one or more of sulfoxide, sulfonate and sulfone. Preferably, it is oxidized to sulfoxide. That is, in the present invention, the oxidized form of methionine is not regarded as methionine. The level of the oxidation can be adjusted mainly by the kind of the oxidizing agent to be added and the amount thereof. The temperature of the aqueous solution is preferably from 10 to 70 ° C, more preferably from 25 to 50 ° C. The pH is preferably 2 to 9, and more preferably 3 to 7. Usually, an oxidizing agent is added to an aqueous gelatin solution whose temperature and pH are constantly adjusted, and the mixture is uniformly mixed. Next, the container is covered with a lid, kept at a constant temperature, and allowed to stand for 15 minutes to 3 days, more preferably for 1 to 24 hours. Regarding the oxidizing agent, the description of Japanese Patent Application No. 6-102485 can be referred to. Usually H₂O₂Can be preferably used.
[0051]
Due to the oxidation, the extinction coefficient (200 to 500 nm wavelength range) of gelatin decreases. Therefore, if reagents having various oxidation levels are prepared and the relationship between the extinction coefficient and the methionine content is determined, thereafter, the methionine content of the gelatin can be easily determined by measuring the extinction coefficient. The amino acid composition of standard gelatin is described in The Theory of The Photographic Process, Chapter 2, Macmillan (1977), and eight molecules of methionine are contained in one molecule. Assuming that the molecular weight of gelatin is 96,000, the methionine content is 83 μmol / g, and the methionine content of conventional gelatin can be considered to be about 80 μmol / g. FIG. 1a₁, A₂In the region, the methionine content is preferably 60 μmol / g or less, more preferably 50 μmol / g or less, still more preferably 40 μmol / g or less, and most preferably 36 μmol / g or less. FIG. 1a₃In the region, the methionine content is preferably 40 μmol / g or less.
[0052]
D. PAO polymer
The polyalkylene oxide polymer (hereinafter referred to as “PAO polymer”) is prepared before nucleation to 5 minutes before the end of growth, preferably up to 10 minutes before, more preferably after nucleation to just before the start of growth. It is preferable to add them in between. The above-mentioned tabular grain formation, furthermore Br⁻It can be more preferably added to the formation of (111) tabular grains having a content of 50 to 100 mol%. With respect to the details of the PAO polymer, the compounds described in European Patent 0514742A1, Japanese Patent Application Nos. 5-118418, 5-191814 and 5-263128 are preferable, and particularly the embodiments described in Japanese Patent Application Nos. 5-191814 and 5-263128. Can be preferably used. The molecular weight of the PAO polymer of the following first to sixth aspects is 500 to 10⁶Is preferably 10³-10⁵Is more preferred. The amount of the PAO polymer in the following first and second embodiments is preferably 0.001 to 20 g / liter, more preferably 0.003 to 10 g / liter. The amount of each polymer of the following third to sixth embodiments is preferably 0.01 to 20 g / liter, more preferably 0.03 to 10 g / liter. The amount of each polymer of the following third to sixth embodiments is preferably 0.01 to 20 g / liter, more preferably 0.03 to 10 g / liter. The pH during grain growth is preferably from 5 to 11, more preferably from 5 to 9.5.
[0053]
The order of the strength of the adsorption power of the organic ether compound to the AgX particles is generally -O-<-S-<-Se-<-Te-. Since the adsorbing power of the oxygen ether group to the AgX particles is weaker than that of the thioether group, the growth of the AgX particles is not strongly suppressed. Since the adsorption to AgX particles is based on Van der Waalska, the adsorption is more selectively performed on the {100} surface than on the {111} surface of the AgX particles. It is Ag on {100} face compared to {111} face⁺And X⁻This is because the induced dipole moment is large because of It is on the edge surface that the {100} plane is likely to appear in the (111) tabular grains, so PAO is adsorbed on the edge surface with a moderate adsorption force rather than on the main plane. Then, the growth rate of the edge surface is changed to the rate of PAO desorption. If the number of adsorbed molecules of PAO per unit area is equal, the growth rate of each unit area is the same for both large and small particles. Therefore, the edge surface of both large particles and small particles grows at a constant speed, and the coefficient of variation of the diameter distribution decreases with the growth.
[0054]
The crystal habit dependence of the adsorption of the PAO polymer can be determined by the following method. A monodisperse cubic grain emulsion and an octahedral grain emulsion having the same surface area are prepared, and a PAO compound is added to each of them to reach an adsorption equilibrium, followed by centrifugation and analysis of a supernatant. For example, when the temperature is higher than the cloud point of the PAO, it can be determined by comparing the spectral transmission intensities. In addition, a method of separating and analyzing the PAO component by chromatography (eg, gel filtration chromatography) can be mentioned. In addition, the comparison can be made by measuring the ionic conductivity of the cubic and octahedral particles by a dielectric loss method and determining the amount of change in ionic conductivity due to the adsorption.
[0055]
Conventional gelatin adsorption on AgX particles usually occurs more strongly on {100} faces than on {111} faces. It is mainly the Ag on the particle surface⁺This is for adsorption based on the interaction with In this case, the adsorption of the PAO polymer to the {100} plane is excluded. However, in the case of the modified gelatin, since the adsorption to the AgX particles is weak, the selective adsorption to the {100} plane of the PAO polymer becomes possible, and the preferable growth characteristics of the above embodiment can be obtained. Since the PAO polymer increases the ionic conductivity of AgBr particles by the adsorption, the {100} plane Br⁻It is thought that the interaction with is large.
Further, the PAO polymer and X⁻Can be determined by the following method. X and X are respectively contained in the aqueous solution containing PAO and the aqueous solution not containing PAO.⁻Insert the selection electrode and X⁻The relationship between the amount of salt added and the electrode potential (relative to the standard electrode) may be determined and compared. X incorporated into PAO polymer⁻The change in the potential is reduced by the amount.
[0056]
A first embodiment of the PAO polymer is HPAO, and is represented by the general formula (1) -a) or (1) -b). The molecular weight of HPEOU includes 96.1 to 100%, preferably 97 to 100% of the molecular weight of the whole molecule (HP1) and the mode (HP2) occupying 4 to 96% of the molecular weight.
In the formula (1), R⁰Is H, or a hydrocarbon having 1 to 10 carbon atoms having at least one polar group (e.g., -CH₂OH, -C₂H₅OH, -CH₂-O-CH₃), Preferably H. R represents an alkylene group having 3 to 10 carbon atoms, and specific examples thereof include -CH (CH₃) CH₂-, -CH₂CH (CH₃)-, -CH₂CH₂CH₂−, − (CH₂)₄-,-(CH₂)₅-, -CH₂CH (C₆H₅)-, And -CH (CH₃) CH₂-, -CH₂CH (CH₃)-Is particularly preferred.
n and m represent the average number of repeating units, and are values of 4 or more, preferably 6 to 10,000, and more preferably 10 to 2000, which satisfy the above-mentioned molecular weight specification.
[0057]
However, since the selectivity of the ring opening position of the cyclic ether during the polymerization is not sufficient, for example,-[CH₂CH (CH₃) O]-and-[CH (CH₃) CH₂O 2] − may be mixed.
The second embodiment of the PAO polymer is PEOD, which is represented by the general formula (a) to (f) in the above formula (2). Here, LPU refers to a lipophilic group other than the HO-HPEOU- group and the HO-LPAOU- group, and is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, acyl group, It refers to an acylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, or an alicyclic group, and is more preferably a compound containing no divalent sulfur, selenium, or tellurium. LPU ′ denotes H, an alkyl group having 1 to 20 carbon atoms,²Is the same as
Specific compound examples of the HPAO are shown in a) to c) of formula (10), and specific compound examples of the PEOD are shown in a) to g) of formula (11).
Here, the substituent is C_dH_{2 d + 1} ⁻, C_dH_{2 d + 1}CO⁻Can be mentioned. d represents an integer of 1 to 12.
[0058]
Embedded image

[0059]
Wherein a and b each represent an integer of 1 to 25;₁~ N₃Is a value of 1 to 10,000 which satisfies the above-mentioned molecular weight specifications of HPAO and PEOD. For other details of the polymers of the first and second embodiments, the description of Japanese Patent Application No. 5-118418 can be referred to.
The third embodiment of the PAO polymer is the same as the general formula (3) [the formula (7) -a described later). ] It contains at least one kind of polymer having a repeating unit of a monomer represented by the following formula: The polymer may be a copolymer with another monomer described below. In that case, the proportion of the monomer of the formula (3) in the polymer is 1 to 100% by weight, preferably 10 to 90% by weight. The fourth embodiment is characterized in that the polymer has at least two kinds of monomers represented by general formula (3) and at least two types of monomers represented by general formula (4) [same as the following formula (7) -c]: : 100 to 100: 1, preferably 5 to 100 to 100: 5 molar ratio.
[0060]
In the formulas (3) and (4), R¹, R⁴May be the same or different, and represents H, a lower alkyl group having 1 to 4 carbon atoms (methyl, ethyl, n-propyl, n-butyl), and H and a methyl group are particularly preferred. R², R⁵May be the same or different and represent a monovalent substituent having 1 to 20 carbon atoms, preferably H, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or an acyl group, particularly preferably H, methyl Groups, ethyl groups, phenyl groups, and acetyl groups are preferred. n and m represent the average number of repeating units, n is 4-600, preferably 4-200, and m is 4-600, preferably 4-200. L and L ′ represent a divalent linking group, and specific examples thereof include —COO—, —CONH—, and —CONH— (CH₂)_C-COO-, -Ph-CH₂O- (Ph: phenylene group), -COOCH₂CH₂O-, -CON (CH₃)-. C indicates an integer of 1 to 20.
[0061]
Specific examples of the monomer represented by the general formula (3) are as follows.

[0062]
Specific examples of the monomer represented by the general formula (4) are as follows.

[0063]
The proportion of the monomer represented by the formula (3) in the copolymer is 1 to 90% by weight, preferably 5 to 85% by weight, more preferably 15 to 70% by weight.
The proportion of the monomer represented by the formula (4) in the copolymer is 1 to 90% by weight, preferably 3 to 70% by weight, more preferably 10 to 50% by weight.
The monomer of the formula (3) and / or the monomer of the formula (4) may be copolymerized with another monomer for use. Specific examples of the other monomers include acrylic esters, methacrylic esters, acrylamides, methacrylamides, vinyl esters, vinyl ketones, allyl compounds, olefins, vinyl ethers, N-vinylamides, and vinyl heterocycles. Compounds, maleic esters, itaconic esters, fumaric esters, crotonic esters. The copolymerization amount of the other monomer is 0 to 99% by weight, preferably 0 to 90% by weight, more preferably 5 to 60% by weight.
[0064]
Specific examples of copolymers of the monomer of the formula (3), the monomer of the formula (4) and other monomers are shown in the formulas (12) -1) to (12) -5). The values in parentheses indicate the weight percentage of each monomer in the polymer.

[0065]
For other details of the PAO polymers of the third and fourth embodiments, the description of the sixth embodiment described later and the description of Japanese Patent Application No. 5-191814 can be referred to.
A fifth aspect of the PAO polymer is that the dispersion medium solution contains at least one polymer containing 1% by weight or more of the repeating unit represented by the general formula (5) and the polymer represented by the general formula (6). In this embodiment, the polymer containing 1% by weight or more of the repeating unit is contained at the above concentration.
In the formula, R represents an alkylene group having 3 to 10 carbon atoms, and specific examples thereof include -CH (CH₃) CH₂-, -CH₂CH (CH₃)-, -CH₂CH₂CH₂−, − (CH₂)₄-,-(CH₂)₅-, -CH₂CH (C₆H₅)-And -CH (CH₃) CH₂-, -CH₂CH (CH₃)-Is particularly preferred.
n and m represent the average number of repeating units, and are values of 4 or more, preferably 6 to 10,000, and more preferably 10 to 2000, which satisfy the above-mentioned molecular weight specification.
[0066]
The sixth embodiment of the PAO polymer is an embodiment in which the following limitation is added to the fifth embodiment. The polymer represented by the formula (5) is at least selected from a vinyl polymer of a monomer represented by the formula (7) -a) and a polymer containing a polyurethane represented by the formula (7) -b). One kind of polymer, wherein the polymer represented by the formula (6) includes a vinyl polymer of a monomer represented by the formula (7) -c) and a polyurethane represented by the formula (7) -d) An embodiment in which the polymer is at least one polymer selected from a polymer and a substituted or unsubstituted polyethylene glycol.
In the above formula, n and m can take values of 4 or more, preferably 4 to 600, more preferably 4 to 80. R, R¹, R², R⁴, R⁵, L, L 'are the same as above. R¹¹, R¹², R^Thirteen, R¹⁴Represents a divalent linking group, and represents an alkylene group having 1 to 20 carbon atoms, a phenylene group having 6 to 20 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms. x, y, z, x ', y', z 'represent the weight percentage of each component, x, x' is 1 to 70, preferably 5 to 40, y, y 'is 1 to 70, preferably 3 -50, z and z 'represent 20-70, preferably 30-60. Here, x + y + z = 100 and x ′ + y ′ + z ′ = 100.
As the repeating unit represented by-(RO)-, only one type may be used in the polymer, or two or more types may be used. Also,-(RO)-or-(CH₂CH₂Two or more types having different average numbers (molecular weights) of O)-repeating units may be used.
[0067]
The polymer represented by the formula (5) can be preferably used as long as it contains the repeating unit of the formula (5). However, a vinyl polymer of the monomer represented by the general formula (7) -a) or And a polymer containing a polyurethane represented by the general formula (7) -b) can be more preferably used, and the former vinyl polymer can be more preferably used.
Specific examples of the monomer represented by the formula (7) -a) are as follows: (7) -a) -1) to (7) -a) -5) Formulas [(3) -a) -1) to (3) -A) -5) Same as the formula].
[0068]
Embedded image

[0069]
In the vinyl polymer, the proportion of the monomer unit represented by (7) -a) is 1 to 100% by weight, preferably 10 to 90% by weight, and more preferably 30 to 70% by weight. Specific examples of the vinyl polymer of the monomer of the formula (7) -a) are represented by formulas (8) -a) -1) to (8) -a) -3), and the polyurethane of the formula (7) -b) Are shown in the formulas (8) -b) -1) to (8) -b) -2). The values in parentheses indicate weight percentage ratios.
(8) -a) -1): (7) -a) -3) / acrylamide copolymer (25/75)
(8) -a) -2): (7) -a) -3) / acrylic acid / acrylamide copolymer (50/30/20)
(8) -a) -3): (7) -a) -3) / acrylic acid copolymer (70/30)
(8) -b) -1): Isophorone diisocyanate / 2,2-bis (hydroxymethyl) propionate sodium / polypropylene oxide (molecular weight 400) / polypropylene oxide (molecular weight 1000) (43.1 / 21.5 / 15. 7 / 19.7).
(8) -b) -2): Toluene diisocyanate / 2,2-bis (hydroxymethyl) butanoic acid sodium / polypropylene oxide (molecular weight 1000)
(29.3 / 20.1 / 50.6).
The polyurethane is basically synthesized by addition of a diol compound and a diisocyanate compound.
[0070]
The polymer represented by the formula (6) can be preferably used as long as it contains the repeating unit of the formula (6). However, a homopolymer of a monomer represented by the general formula (7) -c), Alternatively, a copolymer or a polyethylene glycol, a substituted polyethylene glycol, or a polyurethane represented by the formula (7) -d) can be preferably used, and the homopolymer of the monomer represented by the formula (7) -c) is more preferably used. Can do things.
[0071]
The monomer of the formula (7) -c) may be copolymerized with another ethylenically unsaturated monomer. In this case, the proportion of the monomer represented by the formula (7) -c) in the copolymer is 1 to 100% by weight, preferably 10 to 80% by weight, and more preferably 30 to 70% by weight. Specific examples of the monomer represented by the formula (7) -c) are the same as [(4) -a) -1) to (4) -a) -5) as follows. ].

(6) Other examples of the polymer having a repeating unit represented by the formula include polyethylene glycol, substituted polyethylene glycol having a substituent having 1 to 30 carbon atoms, and polyurethane. The proportion of polyethylene oxide in the polyurethane polymer represented by the formula (7) -d) is 1 to 70% by weight, preferably 5 to 40% by weight.
[0072]
Next, specific examples of the polymer of the monomer represented by the formula (7) -c) are shown in the formula (8) -c), and examples of the polymer of the formula (7) -d) are shown in the formula (8) -d). .
(8) -c) -1) (7)-(c) -3) / acrylamide copolymer (10/90)
(8) -c) -2) 〃 (25/75)
(8) -c) -3) 〃 (50/50)
(8) -c) -4) (7)-(c) -3) Homopolymer
(8) -d) -1) Toluene diisocyanate / 2,2-bis (hydroxymethyl) butanoic acid sodium / polyethylene glycol (molecular weight 1000)
(29.3 / 20.1 / 50.6)
(8) -d) -2) 4,4'-diphenylmethane diisocyanate / 2,2-bis (hydroxymethyl) propionate sodium / polyethylene glycol (molecular weight 400) (45.3 / 11.3 / 43.4)
[0073]
For other details of the fifth and sixth aspects, the description of Japanese Patent Application No. 5-263128 can be referred to.
In the present invention, HP1 of the first aspect, the second to sixth aspects can be preferably used, the second to sixth aspects can be more preferably used, and the third to sixth aspects can be more preferably used. Further, the fifth and sixth aspects are most preferable.
For other details of the PAO polymer, see Davidson et al., Synthetic Detergents, John Wiley & Sons, New York (1987), edited by Tadanori Misawa, Water-Soluble Polymers, Chemical Industry Co. (1990), Hiroshi Horiguchi, New Surface Activity , Sankyo Publishing (1975), Takehiko Fujimoto, Introduction to New Surfactants, Sanyo Chemical Industries (1976), The Chemical Society of Japan, Chemical Handbook, Section 4-6, Maruzen (1984), Tokyuki Yoshida, Surfactant handbooks, engineering books, and the following literatures can be referred to.
The optimum addition ratio of the polymer represented by the formula (5) to the polymer represented by the formula (6) changes depending on the halogen composition of the AgX particles and the growth conditions (temperature, pH, pAg, etc.). However, in the case of the fifth and sixth embodiments, if both polymers are prepared, the optimum conditions can be selected by changing the ratio of the amounts added. However, in the case of the fourth embodiment, it is necessary to prepare a polymer in which the polymerization ratio of the monomer of the formula (3) and the monomer of the formula (4) is variously changed, and it is difficult to respond finely. In addition, a large number of products can be produced in small quantities, resulting in an increase in cost. Therefore, in this regard, the fifth and sixth aspects are more preferable than the fourth aspect.
[0074]
D. Ag⁺And X⁻Supply method
Ag in the growth process⁺And X⁻Can be supplied by 1) a silver salt solution in which a soluble silver salt is dissolved and a halogen salt solution in which a soluble halide salt is dissolved (hereinafter referred to as “X⁻Salt solution), 2) a method of forming an AgX fine particle emulsion in advance and supplying the fine particle emulsion, 3) a splash addition method, and 4) a combination method of the above two methods. it can. Examples of the soluble silver salt and the soluble halogen salt include salts having a solubility in water at room temperature of 1% by weight or more, preferably 10% by weight or more, and are edited by The Chemical Society of Japan, Chemical Handbook, Chapter 8, Maruzen (1993) ) Can be referred to. Usually AgNO₃And Cl⁻, Br⁻, I⁻Alkali metal salts and ammonium salts can be preferably used. The AgX fine particles preferably have a particle diameter (diameter of a circle having an area equal to the projected area of the particles) of 0.15 μm or less, more preferably 0.01 to 0.1 μm, and still more preferably 0.02 to 0.06 μm. . The halogen composition includes AgCl, AgBr, AgI and mixed crystals of two or more thereof.
[0075]
The size distribution preferably has a coefficient of variation of 0 to 0.4, more preferably 0 to 0.2, and still more preferably 0 to 0.1.
The fine particles preferably have substantially no double or more twin planes, more preferably substantially no single twin particles. Further, it is preferable that the film does not substantially have a screw dislocation defect. Here, the term "substantially free" means that the number is preferably 3% or less, more preferably 1% or less, and even more preferably 0 to 0.1%.
The fine particles can be added continuously or intermittently. Further, the halogen composition of the fine particles to be supplied can be changed continuously or intermittently with respect to the supply time. The most preferable combination of the fine grain emulsion having a pH of 1 to 12 and a pX of 0.5 to 6 can be selected.
[0076]
In the case of forming the fine particles, the dispersion medium which strongly adsorbs to the AgX particles enables the formation of the fine particles as defined above. On the other hand, when the fine particles are supplied to grow tabular grains, the bond between the dispersion medium and the AgX grains is preferably weak. This is for promoting the dissolution of the fine particles and promoting the growth of tabular grains. Therefore, after the AgX microparticles are formed in a dispersion medium solution, the treatment is performed, and the Ag / particles per unit weight of the dispersion medium under the same conditions are treated.⁺It is preferable to reduce the ability to form a complex by 10% or more, preferably 30 to 99% or more, more preferably 60 to 95%, and even more preferably 80 to 95%. Here, the processing is H₂O₂And the like, and oxidizing the dispersion medium and / or adding the modifier to chemically modify the amino group. The details of the treatment and other details of the method of adding fine particles can be referred to the description of Japanese Patent Application No. 6-102485.
[0077]
Ag during nucleation, ripening and growth⁺And X⁻Any conventionally known device can be used as the supply device and the particle forming device. The addition holes are provided in the dispersion medium solution, and (number of addition holes / 1 addition liquid) is 2 or more, preferably 4 to 10^FifteenIt is possible to preferably use a mode in which a single porous addition system, in which the addition holes are made of a rubber elastic body film, the holes are opened when the addition is performed, and the holes are closed when the addition is stopped. The details of the method for adding fine particles and the conventional apparatus are described in the following literature, and JP-A-3-21339, 1-183417, 4-34544, 4-193336, 4-330427, 3-155439, 3-15539. -200952, 3-246534, 4-283741, 4-184326 to 184330, 5-1377, 5-45757, 5-61134, 5-337350, 6-11779, U.S. Pat. The description of Japanese Patent Application Nos. 4-240283, 4-302605, and 5-25314 can be referred to.
[0078]
E. FIG. AgX emulsion manufacturing process
Conventionally, the production process of an AgX emulsion is usually carried out in the order of AgX grain formation → rinse water washing → chemical sensitization and spectral sensitization. In the present invention, a desalting step of the emulsion can be added after chemical sensitization and / or after spectral sensitization depending on the purpose other than the production step. In this case, the AgX emulsion conditions at the time of chemical sensitization and the AgX emulsion conditions at the time of spectral sensitization can be selected to be different from the AgX emulsion conditions at the time of coating, and the most suitable conditions for each step can be selected. There is an advantage that you can. Chemical sensitization and spectral sensitization can be performed simultaneously, or one of them can be performed first.
After preparing the emulsion, the emulsion can be washed with water and desalted according to a conventional method. As the desalting method, 1) a Nudel washing method, 2) a method of adding an aggregating agent, adjusting the pH of the emulsion to an aggregation pH, causing the emulsion to aggregate, sedimentation, and removing the supernatant,₂Group and / or carboxyl group, preferably -NH₂When gelatin containing chemically modified groups is included, aggregation and precipitation can be performed without a flocculant or with a smaller amount of addition. 3) a method of removing an aqueous solution in an AgX emulsion using an ultrafiltration membrane, 4) a method of sedimenting AgX particles by a centrifugal sedimentation method and removing a supernatant, 5) a centrifugal filtration method, 6) an electrodialysis method, Can be mentioned. For the details thereof, refer to the following documents, Japanese Patent Publication No. 62-27008, Japanese Patent Application Laid-Open No. 62-113137, Japanese Patent Application Laid-Open No. 3-200952, edited by Misawa, Supplement / Centrifugation, Chemical Industry Co., Ltd. (1985). It can be.
In the case of the emulsion of the present invention, a method of removing 10 to 99.9% of the dispersion medium by using the centrifugal filtration method, adding a new dispersion medium, and replacing the dispersion medium can also be preferably used.
[0079]
F. Chemical sensitization
The AgX emulsion grains of the present invention are preferably Sx sensitized and adsorb spectral sensitizing dyes, where Sx refers to sulfur, selenium, tellurium. As the Sx sensitizer, conventionally known Sx sensitizers can be used. Specific examples thereof include thioureas, rhodanines, oxazolidines, polysulfides, selenoureas, phosphine selenides, selenoamides, and thiosulfates. Salts can be given, and the details can be referred to the descriptions in the following literatures.
The AgX grains of the AgX emulsion of the present invention are preferably further gold sensitized. As the gold sensitizer, a conventionally known gold sensitizer can be used. For example, chloroauric acid, potassium chloroaurate, potassium or sodium aurithiocyanate (chloroauric acid: SCN)⁻= 1: 1 to 1: 100 molar ratio), brominated auric acid, iodoauric acid, gold sulfide, gold selenide and the like.
The ratio of (the number of moles of the gold sensitizer added / the number of moles of the Sx sensitizer) is preferably 4 to 0.2, more preferably 2 to 0.3, and further preferably 1.5 to 0.4. preferable. The amount added to the AgX emulsion was 10^-2-10^-7, Preferably 10^-3-10^-7It is preferable to select an optimum amount from mol / mol AgX.
[0080]
G. FIG. Other
As the dispersion medium at the time of nucleation and ripening, or as a dispersion medium to coexist at the time of growth, one or more kinds of conventionally known water-soluble dispersion media can be selected and used, and gelatin can be preferably used. Regarding conventionally known water-soluble dispersion media, see the following literature and Research Disclosure, Volume 307, Item 307105, November, 1989, Japanese Patent Application No. 6-102485, Japanese Patent Publication No. 52-16365, edited by Tadanori Misawa, water-soluble polymer, Chemical Industry Co. (1987), edited by The Society of Polymer Science, New Polymer Material, One Point 24, Kyoritsu Shuppan (1990), Shinji Nagatomo, edited and marketed for water-soluble polymers, CMC (1984), Ward et al. Reference can be made to the description of the book, The Science and Technology of Gelatin, Academic Press, London (1964). The concentration of the dispersion medium can be selected and used from 0.01 to 10% by weight, preferably 0.05 to 3% by weight.
[0081]
The state of the tabular grain emulsion of the present invention thus prepared immediately after the completion of the growth is expressed as follows. In an AgX emulsion having at least a dispersion medium and AgX grains, 75 to 100%, preferably 90 to 100%, more preferably 97 to 100%, of the total projected area of the AgX grains, and a thickness of 0.02 to 0.1%. Tabular grains having a diameter of 3 μm, preferably 0.03 to 0.15 μm, more preferably 0.03 to 0.1 μm, and an aspect ratio (diameter / thickness) of 2 to 50, preferably 3 to 30. The coefficient of variation is 0 to 0.3, preferably 0 to 0.2, more preferably 0 to 0.1, and 30 to 100% by weight of the dispersion medium, preferably 60 to 100% by weight, more preferably 90 to 100% by weight. ~ 100% by weight (chemically modified -NH₂The relationship between% of the number of bases and methionine content is shown in FIG.₁Region, preferably a₂Region, more preferably a₃Gelatin in the region of Regarding the methionine content, the description in the above section C can be referred to. Further, the coefficient of variation of the thickness distribution of the tabular grains is preferably 0 to 0.3, more preferably 0 to 0.2, and still more preferably 0 to 0.1.
[0082]
After the AgX particles are thus formed, the AgX particles are usually washed with water and chemically sensitized. Further, photographically effective additives such as a spectral sensitizer and an antifoggant are added, and the mixture is coated on a support. The order of addition of the chemical sensitizer, the spectral sensitizing dye, and the antifoggant can be selected in an optimum order according to each purpose. When the dye is added, it is preferred that the particles be uniformly adsorbed with less variation in the adsorption coverage between particles. In this case, it is preferable that the adsorption speed of the added dye is appropriately reduced. That is, the more uniform the admixed dye is and then the adsorption proceeds, the higher the uniformity is. The activation energy required when the dye is adsorbed on the AgX particles is the exchange adsorption energy with the adsorbed dispersion medium molecules. It is mainly the activation energy of the desorption of the dispersion medium molecules.
[0083]
Therefore, in order to slow down the dye adsorption rate, a solution containing the dye may be added to the AgX emulsion at a lower temperature by using a dispersion medium having a larger activation energy for desorption. In this case, a new dispersion medium can be added after the particles are formed and before the pigment is added, or a new dispersion medium can be added after a part or all of the dispersion medium is removed. In this way, after adjusting the type, temperature, pH, and pAg of the dispersion medium to optimally adjust the adsorption strength of the dispersion medium, the dispersion medium is violently passed through a hollow-tube-type rubber elastic porous membrane installed in an AgX emulsion. The dye solution is added instantaneously with stirring. In this case, it is preferable to use a mixing device having substantially no (gas / liquid) interface. Even if mixed vigorously, the amount of foaming can be suppressed. Specifically, {circle around (1)} a reaction vessel which can be expanded to 1.05 times or more, preferably 1.1 to 6 times the original volume together with the added amount of the additive liquid, (Total volume in the reaction vessel) is preferably 0 to 0.3, more preferably 0 to 0.15, and still more preferably 0. (2) The total surface area of the mixed solution is preferably 10 %, More preferably 25-99%, even more preferably 50-98%, in which floating pigs are installed. For other details, refer to the description of Japanese Patent Application No. 4-302605. Can be.
[0084]
Preferred embodiments of the AgX emulsion of the present invention after spectral sensitization are as follows.
1) In an AgX emulsion having at least a spectral sensitizing dye-adsorbed AgX particle and a dispersion medium, the aspect ratio is 75 to 100%, preferably 90 to 100%, more preferably 97 to 100% of the projected area of the AgX particle. Are tabular grains having a diameter of 2 to 50, preferably 4 to 30, and a thickness of 0.02 to 0.3 μm, preferably 0.03 to 0.15 μm, more preferably 0.03 to 0.1 μm. The coefficient of variation of the distribution is 0 to 0.3, preferably 0 to 0.2, more preferably 0 to 0.1, and the coefficient of variation of the adsorption coverage of the dye is 0 to 0.3, preferably 0 to 0.3. 0.2, more preferably 0 to 0.1.
The AgX emulsion of the present invention is preferably sensitized at least with gold. The preferred embodiment in this case is as follows. 2) 10^-7AgX grains sensitized with a gold sensitizer of mol / mol AgX or more and an AgX emulsion having a dispersion medium, 75 to 100%, preferably 90 to 100%, more preferably 97 to 100% of the projected area of the AgX grains. １００100% are tabular grains conforming to the above-mentioned rules, the gold content of the tabular grains is proportional to the surface area of the tabular grains, and the coefficient of variation of the proportional constant between grains is 0 to 0.3, preferably Is 0 to 0.2, more preferably 0 to 0.1.
[0085]
The AgX emulsion of the present invention is preferably sensitized with at least selenium. The preferred embodiment in this case is as follows. 3) 10^-7In an AgX emulsion sensitized with a selenium sensitizer of mol / mol AgX or more and an AgX emulsion having a dispersion medium, 75 to 100%, preferably 90 to 100%, more preferably 97 to 100% of the projected area of the AgX grain. １００100% are tabular grains according to the above definition, the selenium content of the tabular grains is proportional to the surface area of the tabular grains, and the coefficient of variation of the proportional constant between grains is 0 to 0.3, preferably Is 0 to 0.2, more preferably 0 to 0.1.
[0086]
AgX emulsions satisfying two or more, preferably three, of the above 1) to 3) are more preferred.
In order to form a chemical sensitization nucleus according to the above-mentioned rules, the following method can be particularly preferably used. Conventionally, the AgX emulsion was first heated to a chemical ripening temperature, and then a chemical sensitizer was added to the liquid surface of the AgX emulsion to perform chemical ripening. In this case, the chemical sensitization reaction of the AgX particles in contact with the high concentration solution of the chemical sensitizer proceeds rapidly, and the formation of chemical sensitization nuclei becomes non-uniform among the particles. Decreasing the temperature of the AgX emulsion, increasing the pAg, or decreasing the pH decreases the reaction rate. Therefore, in the present invention, the chemical sensitizer is added to the AgX emulsion under the condition that the added chemical sensitizer does not substantially react, and after homogenization, the AgX emulsion is changed to a condition under which the reaction proceeds, and the reaction is performed. Let go. That is, the temperature rises when the temperature is low, decreases when the pAg is high, and increases when the pH is low.
Since the selenium sensitizer and the gold sensitizer are completely uniform in the AgX emulsion, the chance of the unit area on all the AgX grains reacting with the chemical sensitizer is exactly the same. Can be reached.
For the details of the uniform chemical sensitization method and the uniform spectral sensitization method and the details of the method of verifying the uniformity, the description of Japanese Patent Application No. 5-324502 can be referred to.
[0087]
Conventionally, in an AgX emulsion having a dispersion medium and AgX grains, 90 to 100%, preferably 96 to 100%, more preferably 98 to 100% of the total projected area of the AgX grains has a thickness of 0.02 to 0.2%. 12 μm, preferably 0.02 to 0.1 μm, the aspect ratio is 3 to 50, preferably 4 to 50 hexagonal tabular grains, the coefficient of variation of the diameter distribution of the grains is 0 to 0.2, preferably 0 to 0.2. An AgX emulsion having a primary plane shape of 0.1 and a maximum adjacent side ratio of 1 to 1.5, preferably 1 to 1.2, more preferably 1 to 1.1 has never been produced. The use of the method of the present invention makes it possible for the first time to produce such emulsions. The emulsion can be particularly preferably used.
When the (100) tabular grains are observed with a transmission electron microscope at −100 ° C. or lower, a grain image shown in FIG. 2, that is, FIG. 3A may be observed. The particles appear to be particles having an embodiment containing two screw dislocations described in Mignot, Journal of Crystal Growth, Vol. 23, 207 (1974). However, if the observed defect image is a screw dislocation line, it should be observed as shown in FIG. Although a particle corresponding to FIG. 3B may be observed, in many cases, the dislocation line and the vector of anisotropic growth do not always match. The vector of the dislocation line is often 90 ° or 65 to 75 ° with respect to the (100) plane of the edge. FIG. 4 shows examples of observations of various dislocation lines observed by this method.
[0088]
The screw dislocation defect can be observed by the following method. That is, the AgX emulsion containing the tabular grains is coated on an undercoated flat support and dried. Since the film thickness is reduced to about 1/10 by drying, the tabular grains are arranged in parallel with the support. Next, the reagent is cooled to −50 ° C. or lower, preferably −100 to −200 ° C., and cut with a microtome to make a section having a thickness of 0.1 μm or less. The section is cooled to -100 ° C or lower, and a transmission electron microscope photograph of the cross section of the particle is observed. By observing the interference image of the electron beam transmitted through the same region of the sample as it is and the electron beam diffracted by the lattice atoms and transmitted, the lattice image can be observed. When observing the image of several sections, the point at which a screw dislocation line passes through the section is observed. The method of observing the lattice image can be referred to the description of Shigeo Horiuchi, High Resolution Electron Microscope, Kyoritsu Shuppan (1988). In this case, since most of the electron beams pass through the sample, the charge of the sample is small.
[0089]
One end of the adsorption state of the dispersion medium to the AgX particles can be understood by measuring the ion conductivity of the AgX particles. When the ionic conductivity of interstitial silver ion Agi of AgX particles dispersed in gelatin was measured by the dielectric loss method, the pH of the emulsion was changed from pH 7 to pH 4 by HNO.₃When lowered with liquid, the ionic conductivity of the cubic AgBr particles increases. This is the -NH of gelatin₂Group is -NH₃ ⁺And Ag on the particle surface⁺This is considered to be due to the decrease in the adsorbability to the surface. On the other hand, in the case of octahedral AgBr particles, the ion conductivity increases due to the pH change. In this case, -NH of gelatin₃ ⁺And Br on the particle surface⁻The adsorptivity of the coulomb between the membranes increases, and the adsorptivity of the gelatin increases. This is because the particle surface is almost Br⁻Therefore, it is understood that the Coulomb interaction force becomes the main force of the adsorption force. Only when the adsorption is enhanced, -S- in gelatin and Ag⁺May be able to interact. Further, the surface Br⁻Agi that existed in balance with the negative charge of⁺However, it is considered that the neutralization of the negative charge makes Coulomb unnecessary, and the concentration decreases.
[0090]
The obtained particles may be used as host particles and epitaxial particles may be formed at edges and / or corners of the particles. Further, particles having dislocation lines therein may be formed using the particles as a core. Alternatively, the particles may be used as a substrate, and AgX layers having a different halogen composition from the substrate may be laminated to produce various known particles having various particle structures. Regarding these, the description in the following literature can be referred to. Further, a chemically sensitized nucleus is usually provided to the obtained emulsion grains.
[0091]
In this case, the location of the chemical sensitization nucleus and the number / cm²Is preferably controlled. Regarding this, JP-A-2-838, JP-A-2-14633, JP-A-1-201651, JP-A-3-121445, JP-A-64-74540, JP-A-3-73266, JP-A-3-140712, Reference can be made to the description in JP-A-3-1155872.
[0092]
Further, the tabular grains may be used as a core to form a shallow latent emulsion. Also, core / shell type particles can be formed. This is described in JP-A-59-133542, JP-A-63-151618, U.S. Pat. Nos. 3,206,313, 3,317,322, 3,761,276, and 4,269,927. No. 3,267,778 can be referred to.
The AgX emulsion grains produced by the method of the present invention can also be used by blending with one or more other AgX emulsions. The blend ratio can be appropriately selected and used within the range of 1.0 to 0.01.
[0093]
There are no particular restrictions on the additives that can be added to these emulsions during the period from the grain formation to the coating step.^-8-10^-1mol / mol AgX can be added in an added amount. For example, an AgX solvent, a dopant for AgX particles (for example, a Group 8 noble metal compound, another metal compound, a chalcogen compound, an SCN compound, etc.), a dispersion medium, an antifoggant, a sensitizing dye (blue, green, red, infrared) , Panchromatic, orthorectified, etc.), supersensitizers, chemical sensitizers (sulfur, selenium, tellurium, gold and Group 8 noble metal compounds, phosphorus compounds, rhodan compounds, reduction sensitizers alone and two or more of them) ), Fogging agents, emulsion precipitants, surfactants, hardeners, dyes, color image forming agents, color photographic additives, soluble silver salts, latent image stabilizers, developers (hydroquinone compounds, etc.) , A pressure desensitizing agent, a matting agent and the like.
[0094]
The AgX emulsion particles of the present invention and the AgX emulsion produced by the production method can be used for all conventionally known photographic light-sensitive materials. For example, black-and-white silver halide photographic light-sensitive materials [for example, X-ray light-sensitive materials, printing light-sensitive materials, photographic paper, negative films, microphone films, direct positive light-sensitive materials, ultrafine particle dry plate light-sensitive materials (for LSI photomasks, shadow masks) , For liquid crystal masks)] and color photographic light-sensitive materials (for example, negative films, photographic papers, reversal films, direct positive color light-sensitive materials, silver dye bleaching photographs, etc.). Further, there can be mentioned a diffusion transfer type photosensitive material (for example, a color diffusion transfer element, a silver salt diffusion transfer element), a heat development photosensitive material (black and white, color), a high density digital recording material, a holographic material and the like.
[0095]
The amount of silver applied is 0.01 g / m²The above preferred values can be selected. The composition of the photographic material (for example, layer constitution, silver / coloring material molar ratio, silver amount ratio between layers, etc.), exposure, development processing, production equipment of the photographic material, emulsification and dispersion of photographic additives, etc. There is no limitation, and any conventionally known modes and techniques can be used. With respect to conventionally known photographic additives, photographic light-sensitive materials and their constitutions, exposure and development processing, photographic light-sensitive material manufacturing equipment, and the like, the following documents can be referred to.
[0096]
Research Disclosure, Volume 176 (Item 17643) (December, 1978), Volume 307 (Item 307105, November, 1989), Duffin, Photographic Emulsion Chemistry, Focal Press, New York (1966), Bill (EJ Birr), Stabilization of Photographic Silver Silver Hold Emulsion, Focal Press (Focal Press, 1974). ), James James (TH James), Theory of Photographic Process (The Theory of P) Photographic Process, 4th Edition, Macmillan, New York (1977)
[0097]
P. Glafkids, Chemie et Physique Photographiques, 5th Edition, Edition de I 'Usine Nouvelle, Paris (1987) Pond, 2nd Ed. Monterre, Paris (1957); Zelikman et al. (VL Zalikman at al.), Preparation and Coating of Photographic Emulsions (Making and Coating Photographic Emulsion), Focal Press (1964), Hollister (KR Hollister). Journal of Imaging Science, vol. 31, p. 148-156 1987), Maskesky (JE Maskasky), Vol. 30, p. 247-254 (1986), Vol. 32, 160-177 (1988), Vol. 33, 10-13 (1989) )
[0098]
Ed., Freezer et al., Die Grundlagen Der Photographischen Prozesses Mit Silverhalogeniden, Akademichsche Verlaggesellschaft, Akademische Verlaggeschaft, 68, 1967.
JCIA Monthly Report, December 1984, p. 18-27, Journal of the Photographic Society of Japan, 49, 7-12 (1986), 52, 144-166 (1989), 52, 41-48 (1989), JP-A-58-113926. Nos. 113928, 59-90841, 58-111936, 62-99751, 60-143331, 60-143332, 61-14630, 62-6251, 63-220238 No. 63-151618, No. 63-281149, No. 59-133542, No. 59-45438, No. 62-269958, No. 63-305343, No. 59-142439, No. 62-253159, No. 62-266538, No. 63-107813, No. 64-26839, No. 62-157024, No. 62-192036
[0099]
JP-A-1-297649, JP-A-2-127635, JP-A-1-158429, JP-A-2-42, JP-A-2-24643, JP-A-1-14633, JP-A-2-838, JP-A-2-28638, Nos. 3-109439, 3-175440, 3-121443, 2-73245, 3-119347, U.S. Pat. Nos. 4,636,461, 4,942,120, 4, Nos. 269,927, 4,900,652, 4,975,354, European Patent No. 0355568A2, Japanese Patent Application Nos. 2-326222, 2-415037, 2-266615 and 2-266615. Nos. 43991, 3-160395, 2-142635, 3-146503 and 4-77261.
The emulsions of the present invention are described in JP-A-62-269958, JP-A-62-266538, JP-A-63-220238, JP-A-63-305343, JP-A-59-142539, JP-A-62-253159, JP-A-1-131541, JP-A-1-297649, JP-A-2-42, JP-A-1-158429, JP-A-3-226730, JP-A-4-151649, Japanese Patent Application No. 4-179996, European Patent No. 0508398A1, JP-A-6-258788, It can be preferably used as a constituent emulsion of the light-sensitive material of the embodiment of JP-A-6-273860.
[0100]
BEST MODE FOR CARRYING OUT THE INVENTION
[0101]
【Example】
Next, the present invention will be described in more detail by way of examples, but embodiments of the present invention are not limited thereto.
Example 1
Put gelatin solution 1 [H₂O 1.2 liters, containing 1.0 g gelatin 1 and 0.25 g KBr, HNO₃  3N solution adjusted to pH 2.0], keeping the temperature at 40 ° C., and stirring the Ag-1 solution (AgNO₃  60 g / liter) and X-1 solution (H₂O 1 liter, KBr 43.2 g, gelatin 1 0.8 g) was added at 30 ml / min for 1 minute to form nuclei. After stirring for 2 minutes, 30 ml of a KBr-1 solution (100 g / liter of KBr) was added, and the temperature was raised to 60 ° C. for 10 minutes. After the first aging for another 12 minutes, the ammonium sulfate solution [(NH₄)₂SO₄4g, H₂O 20 ml] and 1N NaOH solution were added to adjust the pH to 9.1. After a second aging for 10 minutes, gelatin solution 2 [25 g of gelatin 2, H₂O130ml, KBr 0.15g] and HNO₃  The pH was adjusted to 6.3 with a 3N solution. At this time, 96.1% by weight of the dispersion medium becomes gelatin having a phthalation rate of 96% and a methionine content of 34 μmol / g. Using Ag-1 solution and X-1 solution, simultaneous addition was performed while maintaining pBr at 1.68. 80 ml of the Ag-1 solution was added at 6.6 ml / min. Next, Ag-2 solution (AgNO₃  (200 g / liter) and X-2 solution (146 g / liter) were added simultaneously while maintaining the same pBr. The Ag-2 solution was added for 40 minutes at an initial flow rate of 3 ml / min and a linear flow rate acceleration of 0.3 ml / min. After stirring for 1 minute, 3 ml of the emulsion was sampled, and a transmission electron micrograph image (TEM image) of a replica of the formed particles was observed. The characteristic values were as follows.
99% or more of the total projected area (hereinafter referred to as “SA”) of all AgX grains are hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.05 μm, and an average diameter of 2.1 μm. , Average aspect ratio 42, C.I. V. The value was 0.09.
[0102]
Next, the emulsion was cooled to 30 ° C.₃  The pH was lowered to 3.9 with a 1N solution to coagulate and sediment the emulsion. The emulsion was washed three times with pure water, and a gelatin solution was added. The pH was adjusted to 6.4 with 1N NaOH solution and to 2.8 with 1N NaBr solution to redisperse the emulsion. The emulsion was placed in the closed-type variable-volume container described in Example 1 of Japanese Patent Application No. 5-324502, and a 0.3 g / liter solution of sensitizing dye 1 was added thereto at 70 ° C. while stirring at 40 ° C. by 70% of the saturated adsorption amount. did. The whole amount was added within 3 seconds through the hollow tube-shaped elastic porous membrane in the same manner as in the example. After stirring for 15 minutes, the solution was transferred to the second closed-type variable-volume container. While keeping the temperature of the emulsion at 45 ° C., a gold sensitizer (aqueous solution of chloroauric acid: NaSCN = 1: 20 molar ratio) was added to 1.2 × 10^-5Mol / mol AgX only, and then 2 × 10 2 chalcogenide sensitizer Sx1^-5Only mol / mol AgX was added. The addition was performed within 3 seconds from each of the independent hollow tubular elastic porous membranes of the above embodiment.
The temperature of the emulsion was raised to 60 ° C and ripened for 20 minutes. The temperature was lowered to 40 ° C., and an antifoggant (4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene) was added to 3 × 10^-3Only mol / mol AgX was added, a thickener and a coating aid were added, and the resultant was coated on a TAC (cellulose triacetate) base together with a protective layer, followed by drying.
However, gelatin 1 was a deionized alkali-treated bone gelatin having a weight average molecular weight of 30,000 and a methionine content of 34 μmol / g, gelatin 2 was gelatin obtained by phthalating gelatin 1 at a phthalation rate of 96%, and gelatin 3 was a methionine content of 50 μmol. / G Deionized alkali treated unmodified bone gelatin.
[0103]
Embedded image

[0104]
Example 2
Example 1 was the same as Example 1 except that 1.0 g of EPA1 was mixed into the gelatin solution 2. When 3 ml of the emulsion was sampled and a TEM image of a replica of the formed particles was observed, the characteristic values were as follows.
99% or more of SA is hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.09 μm, an average diameter of 1.56 μm, an average aspect ratio of about 17, and C.I. V. The value was 0.075. Thereafter, the same treatment as in Example 1 was performed to obtain a coated sample 2. Here, EPA1 is a compound of the formula (3) -a) -2): (4) -a) -4) A compound of the formula: acrylamide = 25: 25: 50% by weight and a weight average molecular weight Is 33,000.
[0105]
Example 3
Example 1 was the same as Example 1 except that EPA2 and EPA3 were mixed into the gelatin solution 2 in an amount of 1.0 g each. When the TEM image of the replica of the formed particles was observed, the characteristic values were as follows. 99% or more of SA is hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.09 μm, an average diameter of 1.56 μm, an average aspect ratio of about 17, and C.I. V. The value was 0.07. FIG. 5 shows a TEM image showing the particle structure of the particles. The obtained coating sample was used as coating sample 3. EPA2 and EPA3 refer to the following compounds. EPA2 is H₂C = C (CH₃) -COO- [CH₂CH (CH₃) O]₁₂-H: acrylamide = 25: 75 A copolymer having a polymerization ratio, EPA3 is H₂C = C (CH₃) -COO- (CH₂CH₂O)₂₃-CH₃: Acrylamide = 25: 75 refers to a polymer in a weight ratio.
[0106]
Example 4
The procedure up to the end of the second ripening was the same as in Example 1. Next, HNO₃  After adding 1N solution to adjust the pH to 6.2, the temperature was lowered to 30 ° C., the emulsion was put in a truncated cone type centrifuge, centrifuged, and the supernatant was removed. The removal volume ratio was 93% of the original emulsion. Next, gelatin solution 2 was added to adjust the pH to 6.2, redispersed, and the emulsion was transferred to the original container. The temperature was adjusted to 60 ° C., and 7 ml of a 10 g / liter solution of EPP1 was added as a PAO compound. When 3 ml of the emulsion was sampled and a TEM image of a replica of the formed particles was observed, the characteristic values were as follows.
99% or more of SA is hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.11 μm, an average diameter of 1.41 μm, an average aspect ratio of about 12.8, and C.I. V. The value was 0.075. Thereafter, the same treatment as in Example 1 was performed to obtain a coated sample 4. Here, EPP1 is a block copolymer of polyethylene oxide and polypropylene oxide (molecular weight: about 3200), and is a product name Pluronic 31R1 manufactured by BASF. It is a PAO polymer corresponding to HP2.
[0107]
Example 5
A gelatin solution 51 [H₂O 1.2 liters, gelatin 1 1.7 g, KBr 1.2 g, HNO₃  PH is adjusted to 3.0 with 1N solution], and while keeping the temperature constant at 30 ° C, an Ag-51 solution (AgNO₃  100 g / l) and KBr-51 solution (KBr 72 g / l) at 50 ml / min for 1 minute to form nuclei. After stirring for 1 minute, 10 ml of KBr-2 solution (KBr 300 g / liter) was added, and the temperature was raised to 60 ° C. in 10 minutes. After the first aging for 7 minutes, then gelatin solution 3 (25 g of gelatin 3, H₂O. 135 ml) was added, the temperature was brought to 37 ° C and the pH was adjusted to 9.5 with 1N NaOH solution. While maintaining the pH at 9.5, phthalic anhydride solution 1 (12% by weight of phthalic anhydride dissolved in dry acetone) was added at a constant flow rate over 15 minutes. Stirring was continued for another 20 minutes while maintaining the pH at 9.5. Next, HNO₃  The pH was adjusted to 4.0 with a 3N solution, the emulsion was coagulated and precipitated, and the supernatant was removed. Pure water was added, the aggregated emulsion was washed with water, and the supernatant was removed. 1.3 liters of pure water containing 1 g of EPA1 was added, and the pH was adjusted to 6.4 with a NaOH solution. The temperature was raised to 60 ° C., and a NaBr solution was added to obtain pBr 1.6.
[0108]
Ag-52 liquid (AgNO₃  (120 g / l) and the X-52 solution (KBr 90 g / l) were simultaneously added for 32 minutes while maintaining the pBr at 1.68. The initial flow rate of the Ag-52 solution was 12 ml / min, and the linear flow rate acceleration rate was 0.6 ml / min. After stirring for 1 minute, 3 ml of the emulsion was sampled, and a TEM image of a replica of the formed particles was observed. The characteristic values were as follows. 99% or more of SA is hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.09 μm, an average diameter of 1.3 μm, an average aspect ratio of about 14.4, and C.I. V. The value was 0.072.
The emulsion was sampled, centrifuged, and the supernatant was taken. The temperature was adjusted to 30 ° C., the pH of the supernatant was adjusted to 4.0, the mixture was aggregated, and the supernatant was removed. Washed three times with pure water. After the aggregate was dried and the weight of gelatin was measured, pure water and a NaOH solution were added and redispersed to obtain a 1% by weight solution. A 1% by weight solution of gelatin 3 was used as a comparative sample, and the phthalation ratio was determined by the formal titration method. The phthalation ratio was 95%. Therefore, 100% of the dispersion medium during the particle growth was gelatin having a phthalation ratio of 95% and a methionine content of 34 μmol / g.
Next, the temperature of the emulsion was lowered to 30 ° C., the pH was adjusted to 4.0, and the emulsion was coagulated and settled. (Removal of supernatant liquid → rinsing with pure water) was repeated three times, and then gelatin solution 3 was added. The subsequent steps were the same as in Example 1 to obtain a coating sample 5.
[0109]
Example 6
In Example 1, gelatin solution 1 was replaced with gelatin solution 4 [H₂O 1.2 liters, containing 1.0 g gelatin 2 and 0.25 g KBr, HNO₃Solution and NaOH solution to adjust the pH to 5.0], and replace solution X-1 with solution X-61 (H₂O1 liter, 43.2 g of KBr, and 0.8 g of gelatin 2). In this case, 100% of the dispersion medium during nucleation, ripening and growth is gelatin having a phthalation rate of 95% and a methionine content of 34 μmol / g. When the TEM image of the replica of the formed particles was observed, the characteristic values were as follows. 99% or more of SA is hexagonal tabular grains having a maximum adjacent side ratio of 1 to 1.2, an average thickness of 0.046 μm, an average diameter of 2.19 μm, an average aspect ratio of 47.6, and C.I. V. The value was 0.085.
[0110]
Example 7
A coating sample 7 was obtained in the same manner as in Example 6 except that the emulsion was washed with water and redispersed in the following manner. After grain formation, the temperature was adjusted to 30 ° C., and the emulsion was put in a frustum-type centrifuge, centrifuged, and the supernatant was removed. The removal amount corresponded to 92% of the mother liquor amount. After 2 L of pure water was added and rinsed, the mixture was centrifuged to remove a supernatant corresponding to 92% of the mother liquor. A gelatin solution containing 50 g of gelatin 3 was added to adjust the pH to 6.4 and pBr 2.8, and the emulsion was redispersed.
[0111]
Comparative Example 1
(111) Tabular grains were prepared based on Example 1 of EP 0514742 A1. 100% by weight of the dispersion medium at the time of particle growth had a methionine content of 0 μmolg and a phthalation rate of 0%.
When the TEM image of the replica of the generated particles was observed, b₂The total projected area of the ≧ 1.32 grains accounted for about 32% of SA. A coagulating sedimentation agent was added to the emulsion, and the emulsion was washed with water according to a conventional method. Gelatin solution 3 was added to pH 6.4, pBr 2.8, and the emulsion was redispersed. After that, a coated sample was prepared in the same manner as in Example 1 to obtain a coated sample 21. However, the spectral sensitizing dye and the chemical sensitizer were added as in the conventional method. FIG. 6 shows an example of the particle structure of the generated particles.
[0112]
The coated samples obtained in Examples 1 to 7 and Comparative Example 1 were exposed for 0.1 second through a minus blue filter and an optical wedge that transmit light having a wavelength of 500 nm or more. Next, development was carried out at 20 ° C. for 10 minutes using a MAA-1 developer (described in Journal of Photographic Science, vol. 23, 249-256 (1975)). Stopping, fixing, washing with water, and drying were performed according to a conventional method, and sensitometry was performed.
The results obtained (relative value of sensitivity / granularity) are shown in Table 2. The higher the relative value, the better the photographic performance.
The sensitivity was determined by the reciprocal of the exposure amount giving a density of (fog + 0.2). The graininess was determined by uniformly exposing the sample with a light amount giving a density of (fogging +0.2), and after performing the above-described development processing, Macmillan, Theory of the Photographic Process, p. 619.
[0113]
Example 8
Example 7 was the same as Example 7 except that the phthalated gelatin used for the gelatin solution 4 and the X-61 solution were replaced with the gelatins 81 to 86 shown in Table 2. The methionine content and the phthalation ratio of the gelatins 81 to 89 are as shown in Table 3. The coated samples of the AgX emulsion prepared using the gelatins 81 to 89 were referred to as coated samples 81 to 89, respectively.
The coated sample was exposed for 0.1 second through the minus blue filter and an optical wedge. Next, development was performed at 20 ° C. for 10 minutes using a MAA-1 developer. Table 3 shows the results [relative value of (sensitivity / granularity)] obtained by sensitometry. FIG. 1a₁, Preferably a₂And more preferably a₃The most favorable photographic properties were obtained when using gelatin in the area of
[0114]
[Table 2]

[0115]
[Table 3]

[0116]
Example 9
A gelatin solution 4 [H₂O, 1.2 liters, 20 g of gelatin 1, 0.5 g of NaCl, HNO₃  PH was adjusted to 4.0 with 1N solution], kept at 40 ° C, and stirred with Ag-91 solution (AgNO₃  200 g / liter) and the X-91 solution (69 g / liter of NaCl) were added simultaneously at 50 ml / min for 15 seconds. After stirring for 1 minute, X-92 solution (containing 6 g of NaCl and 15 g of KBr in 1 liter) was added at 60 ml / min for 24 seconds. After stirring for 1 minute, the Ag-91 solution and the X-91 solution were simultaneously mixed and added at 50 ml / min for 1 minute. After the nucleation, the temperature was raised to 37 ° C., a 1N NaOH solution was added to adjust the pH to 9.2, and the phthalic anhydride solution 1 was added over 15 minutes while maintaining the pH at 9.3. Stirring was continued for another 20 minutes while maintaining the temperature at 9.3. HNO₃  The pH was adjusted to 4.0 with a 3N solution, the emulsion was coagulated and precipitated, and the supernatant was removed. 1.3 liters of pure water containing 2.5 g of NaCl was added, the pH was adjusted to 6.0 with a NaOH solution, and the mixture was redispersed. HNO₃The solution was adjusted to pH 5.3 and heated to 75 ° C. for 12 minutes. After aging for 18 minutes, 10 ml of NaCl-1 solution (100 g / liter of NaCl) was added, and aging was performed for another 5 minutes. Here, the aging was completed. The Ag-91 solution was added at 7 ml / min, and the silver potential was adjusted to 140 mV.
[0117]
While keeping the silver potential at 140 mV, the Ag-91 solution and the X-91 solution were simultaneously mixed and added. The initial flow rate of the Ag-91 solution was 7 ml / min, the linear flow acceleration amount was 0.05 ml / min, and the total addition amount was 290 ml. Next, a solution of Ag-91 and a solution of X-93 (containing 23 g of KBr and 59 g of NaCl per liter) were added simultaneously while keeping the silver potential at 120 mV. The Ag-91 solution was added at 8 ml / min for 7 minutes. Next, Ag-91 solution and X-94 solution (containing 45 g of KBr and 50 g of NaCl in 1 liter) were added at 8 ml / min for 7 minutes while keeping the silver potential at 120 mV. After further stirring for 1 minute, the temperature was lowered to 30 ° C.₃The pH was adjusted to pH 4.0 by coagulation and sedimentation of the emulsion.
[0118]
After the emulsion was washed with pure water, a gelatin solution was added, and the pH was adjusted to 6.1 and pCl to 2.2 with a NaOH solution. 3 ml of the emulsion was sampled, and a TEM image of a replica of the formed particles was observed. The characteristic values were as follows. About 94% of SA (aspect ratio ≧ 3) is (100) tabular grains whose main plane shape is a right-angled parallelogram, and has an average thickness of 0.12 μm, an average diameter of 1.3 μm, and an average aspect ratio of about 10. 8, C.I. V. The value was 0.25.
The emulsion temperature was set to 40 ° C., and a 0.3 g / liter solution of sensitizing dye 2 was added for 3 seconds by 65% of the saturated adsorption amount using the porous film addition system. After stirring for 15 minutes, the emulsion was transferred to the next container, and while keeping the temperature of the emulsion at 40 ° C, 2.5 × 10^-5Mol / mol AgX only, then add chloroauric acid^-5Only mol / mol AgX was added. After raising the temperature to 50 ° C. and aging for 15 minutes, 3 × 10^-3Only mol / mol AgX was added and the temperature was brought to 40 ° C. A thickener and a coating aid were added, and the mixture was coated on a TAC base together with a protective layer, and dried to obtain a coated sample 9.
[0119]
Embedded image

[0120]
Example 10
The procedure up to the end of nucleation was the same as in Example 9. Next, the emulsion was placed in a frustum-type centrifuge, centrifuged, and the supernatant was removed. The removal amount was 95% of the mother liquor amount. Next, gelatin solution 2 was added to adjust the pH to 5.3, the emulsion was redispersed, and the emulsion was returned to the original reaction vessel. At this time, 96.1% by weight of the dispersion medium becomes gelatin having a phthalation ratio of 96% and a methionine content of 34 μmol / g. (2.6 g of NaCl, H₂O 20 ml) was added and the temperature was raised to 75 ° C. in 12 minutes. After the temperature rise, a coating sample 10 was obtained through the same steps as in Example 9.
When the TEM image of the replica of the formed particles was observed, the characteristic values were as follows. About 94% of SA (aspect ratio ≧ 3) is a (100) tabular grain whose main plane shape is a rectangular parallelogram, having an average thickness of 0.13 μm, an average diameter of 1.25 μm, and an average aspect ratio of about 9.6. C. of the tabular grains. V. The value was 0.26.
[0121]
Comparative Example 2
A coating sample 22 was prepared in the same manner as in Example 9 except for the following steps. That is, after the completion of nucleation, a NaCl solution (1.6 g of NaCl, H₂O. 20 ml), pH 5.3, and start the temperature raising step to 75 ° C. The desalting step after the crystal growth is performed by a conventional coagulation sedimentation washing method in which a coagulation sedimentation agent is added. 100% by weight of the dispersion medium during grain growth has a phthalation ratio of 0% and a methionine content of 34 μmol / g.
When the TEM image of the replica of the formed particles was observed, the characteristic values were as follows. About 90% of SA (aspect ratio ≧ 3) is (100) tabular grains whose main plane shape is a rectangular parallelogram, and has an average thickness of 0.19 μm, an average diameter of 1.03 μm, and an average aspect ratio of about 5.4. C. of the tabular grains. V. The value was 0.30.
The coated samples 9, 10, and 22 were passed through a minus blue filter for 10 minutes.^-2Exposure for 2 seconds and development. As a result of sensitometry, relative values of (sensitivity / granularity) were 112 for sample 9, 110 for sample 10, and 100 for sample 22, confirming the effect of the method of the present invention.
[0122]
【The invention's effect】
When the AgX emulsion thus prepared is coated on a support in one or more layers to produce a photographic light-sensitive material, a photographic light-sensitive material having low fog density, excellent sensitivity and granularity can be obtained. Compared to the embodiment of EP 514 742 A, the optimum addition amount of the PAO polymer is about 20% or less, so that there is also an advantage that the adsorption prevention of other photographically effective additives is small.
[Brief description of the drawings]
FIG. 1 shows a preferable combination range of methionine content (μmol / g) vs. chemical modification of amino group (%) of gelatin used in the present invention. Of FIG.a ₁ The upper limit line of the region indicates the modification rate = 100%,a ₃ The upper limit line of the region indicates the modification rate = 97%.
FIG. 2 shows an example of a crystal structure (dislocation line structure) of a (100) tabular grain.
FIG. 3 is a schematic structural view of a dislocation line.
FIG. 4 shows examples of various types of crystal structures (dislocation line structures) observed.
FIG. 5 shows the crystal structure of the tabular grains obtained in Example 3.
6 shows the crystal structure of the tabular grains obtained in Comparative Example 1. FIG.

Claims (8)

In a dispersion medium solution containing water and a dispersion medium, at least 75 to 100% of the total projected area of the silver halide grains through a nucleation, ripening, and growth process has a thickness of 0.02 to 0.3 μm and an aspect ratio of In a method for producing silver halide grains which are tabular grains having a diameter / thickness of 2 to 50, 30 to 100% by weight of the dispersion medium in the growing process is gelatin having the following characteristics (a). A method for producing silver halide grains, characterized in that:
(A) Relationship of methionine content of a few percentage% and said gelatin to -NH ₂ group is chemically modified of the gelatin is in the region of a ₁ in FIG. 1. A polymer in which the dispersion medium solution has a repeating unit of polyalkylene oxide, the molecular weight of [represented by the general formula (1) -a) or (1) -b)] HPAO a 500 to ⁶ or PEOD [ Represented by any one of formulas (2) -a) to -f)] of 0.001 g / liter or more.

Here, R ⁰ is H or a hydrocarbon having 1 to 10 carbon atoms having at least one polar group, and is preferably H. R represents an alkylene group having 3 to 10 carbon atoms.
n and m represent the average number of repeating units, and are values of 4 or more that satisfy the above molecular weight specification.

Here, LPU refers to a lipophilic group other than the HO-HPEOU- group and the HO-LPAOU- group, and is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, acyl group, It refers to an acylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, and an alicyclic group. Here, HPEOU and LPAOU have the same meanings as in the general formulas (1) -a) and (1) -b), and LPU 'indicates H and an alkyl group having 1 to 20 carbon atoms. The dispersion medium solution contains at least one kind of polymer containing 1% by weight or more of the repeating unit of the monomer represented by the general formula (3) in an amount of 0.01 g / L or more, and has a molecular weight of 500 to 10 ^{6. The} method for producing silver halide grains according to claim 1, wherein

In the formula, R ¹ represents H, a lower alkyl group having 1 to 4 carbon atoms, and R ² represents a monovalent substituent having 1 to 20 carbon atoms. R ³ represents an alkylene group having 3 to 10 carbon atoms, and L represents a divalent linking group. n represents the average number of repeating units and is from 4 to 600. The dispersion medium solution contains at least 0.01 g / liter of a copolymer containing at least two kinds of monomers represented by the general formula (3) and at least two kinds of the monomers represented by the general formula (4), respectively. method for producing silver halide grains as claimed in claim 1, wherein the molecular weight of the copolymer, characterized in that it is 500 to ^6.
Formula ^{_{(4) CH 2 = C (}} R 4) -L '- (CH 2 CH 2 O) m -R 5
In the formula, R ⁴ represents H, a lower alkyl group having 1 to 4 carbon atoms, R ⁵ represents a monovalent substituent having 1 to 20 carbon atoms, and L ′ represents a divalent linking group. m represents the average number of repeating units and is from 4 to 600. The dispersion medium solution contains at least one polymer containing 1% by weight or more of the repeating unit represented by the following general formula (5) and 1% by weight or more of the repeating unit represented by the general formula (6). at least one kind of containing respectively 0.01 g / l or more, a manufacturing method of the silver halide grains of claim 1, wherein the molecular weight of each polymer is characterized in that a 500 to ⁶ of the polymer.
General formula (5)-(RO) _n-
Formula _{(6) - (CH 2 CH} 2 O) m -
In the formula, R represents an alkylene group having 3 to 10 carbon atoms.
n and m represent the average number of repeating units and are 4 or more that satisfy the molecular weight specification. The polymer having a repeating unit represented by the general formula (5) is a vinyl polymer containing a monomer represented by the following general formula (7)-(a) as a constituent component, and a general formula (7)-(b) At least one kind of polymer selected from polymers containing polyurethane represented by the following general formula (6), wherein the polymer having a repeating unit represented by the general formula (6) is represented by the following general formulas (7) to (c). And at least one polymer selected from a substituted or unsubstituted polyethylene glycol, and a polymer containing a polyurethane represented by the general formulas (7) to (d). The method for producing silver halide grains according to claim 5, wherein
Formula ^{_{(7) -a) CH 2 =}} C (R 1) -L- (R 3 -O) n -R 2
General formula (7) -b)
- [O - _{(R-O) n] x} - [O - ^R 11 -O] _y - ^[CONH-R 12 -NHCO] _Z -
Formula ^{_{(7) -c) CH 2 =}} C (R 4) -L '- (CH 2 CH 2 O) m -R 5
General formula (7) -d)
Among ^[CONH-R 14 -NHCO] _{Z '111,} - - _{[O- (CH 2 CH 2 O)} m ] _X' - ^[O-R 13 -O] _{y '}
n and m represent the average number of repeating units, and are 4-600. R ¹ and R ⁴ represent H or a lower alkyl group having 1 to 4 carbon atoms. R ² and R ⁵ represent H or a monovalent substituent having 1 to 20 carbon atoms. L and L 'represent a divalent linking group. R ¹¹ , R ¹² , R ¹³ and R ¹⁴ represent a divalent linking group, and represent an alkylene group having 1 to 20 carbon atoms, a phenylene group having 6 to 20 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms. x, y, z, x ', y', z 'represent the weight percentage of each component, x, x' is 1-70, y, y 'is 1-70, z, z' is 20-70. Represent. Here, x + y + z = 100 and x ′ + y ′ + z ′ = 100. R represents an alkylene group having 3 to 10 carbon atoms. The principal plane of the tabular grains is a {100} plane or a {111} plane, and the coefficient of variation (standard deviation / average diameter) of the diameter distribution of the grains is 0 to 0.3. 2. The method for producing silver halide grains according to item 1. In a silver halide emulsion having at least a dispersion medium and silver halide grains, 75 to 100% of the total projected area of the silver halide grains has a thickness of 0.02 to 0.3 μm and an aspect ratio (diameter / thickness). Are 2 to 50 tabular grains, the coefficient of variation (standard deviation / average diameter) of the diameter distribution of the grains is 0 to 0.3, and 30 to 100% by weight of the dispersion medium is (chemically modified − the silver halide emulsion NH ₂ cardinality relationship% and methionine content of and wherein the gelatin) in the region of a ₁ in FIG. 1.

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