JP4070587B2 - Planographic printing plate precursor - Google Patents

Description

【００５９】
式（１）中、Ｘは３価の原子または原子団を表し、中でも、窒素原子またはメチン基（ＣＨ）が好ましく、互変異性を容易に起こす観点から窒素原子であることが特に好ましい。
【００６０】
本発明のチオール化合物としては、有機化合物のいずれかに−ＳＨ基を有するものが挙げられ、炭化水素系化合物に−ＳＨ基を有するものが一般的である。−ＳＨ基は分子内に少なくとも１つ有すればよいが、複数の−ＳＨ基を有するものであってもよいことは言うまでもない。
鎖状の化合物としては、脂肪族炭化水素の側鎖或いは末端に−ＳＨを有するものが挙げられる。これらの炭化水素化合物は、直鎖状であっても分岐鎖を有するものであってもよく、さらに水酸基、ハロゲン原子、アミノ基等の置換基を有するものであってもよい。
また、炭化水素系化合物内のメチレン基は、エーテル、チオエーテル、エステル、アミド、ウレア、チオウレア等の２価の有機基で置換されていてもよい。
このような化合物としては、例えば、エタン、ブタン、ヘキサン、ノナン、デカン、ドデカン、オクタデカンなど炭素原子数２〜１８程度の直鎖状炭化水素の片末端、或いは両末端に−ＳＨ基を導入した化合物、炭素原子数２〜１８程度の炭化水素鎖内の炭素上に−ＳＨ基を導入した化合物、およびそれらの炭化水素鎖内のメチン基をエーテル結合、エステル結合で置換した化合物などが挙げられる。
環状の化合物としては、脂環炭化水素、芳香族炭化水素、縮合多環系炭化水素、さらには、ヘテロ環化合物などが挙げられる。また、分子内に互いに独立した２以上の環構造を有するものであってもよい。環状炭化水素系化合物においても、環構造に−ＳＨ基の他、アルキル基、ハロゲン原子、水酸基などの置換基を有するものであってもよい。
このような化合物としては、シクロヘキサン、ベンゼン、ナフタレン、などの環状炭化水素に−ＳＨ基を置換した化合物、環状炭化水素上のアルキル基などの置換基上に−ＳＨ基を置換した化合物、ヘテロ環に−ＳＨ基を置換した化合物などが挙げられる。
【００６１】
前述したように、チオール化合物として、分子量が比較的大きいものが好ましいが、直鎖状炭化水素化合物においては、分子量を大きくすると溶解性が低下する傾向があり、塗布液調製上の観点からは、分岐鎖を有するものや環構造を有するものが好ましい。
なかでも、前記したように互変異性を有するものが好ましいという観点から、分子内に共役二重結合を有する芳香族チオール化合物やヘテロ環含有チオール化合物が挙げられ、芳香族チオール化合物が特に好ましい。
さらに、通常は−ＳＨ基を有する形態で記述される、−Ｃ＝Ｓを有するいわゆるチオン化合物（前記一般式（１）の▲２▼で表される構造を有する如き化合物）も、本発明のチオール化合物として好適に用いられ、そのような化合物としては、例えば、チオウレア系化合物、チオアミド化合物等が挙げられる。
以下に、本発明に好適に用いられるチオール化合物の具体例を示すが、本発明はこれらに限定されるものではない。
【００６２】
【化２】

【００６３】
【化３】

【００６４】
【化４】

【００６５】
【化５】

【００６６】
【化６】

【００６７】
【化７】

【００６８】
【化８】

【００６９】
【化９】

【００７０】
【化１０】

【００７１】
本発明に係るチオール化合物は、記録層の全固形分中、０．２〜２０質量％添加されることが好ましく、０．５〜１０質量％添加されることがさらに好ましい。添加量が少なすぎると、優れた現像ラチチュードおよび画像コントラストが得難く、添加量が多すぎると塗膜の皮膜特性が低下する傾向にある。
【００７２】
＜（Ａ）アルカリ可溶性樹脂＞
本発明の記録層に使用する（Ａ）アルカリ可溶性樹脂としては、高分子中の主鎖および／または側鎖に酸性基を含有する単独重合体、これらの共重合体またはこれらの混合物を包含する。
中でも、下記（１）〜（６）に挙げる酸性基を高分子の主鎖および／または側鎖中に有するものが、耐現像性の点、アルカリ水溶液に対する溶解性の点で好ましい。
【００７３】
（１）フェノール基（−Ａｒ−ＯＨ）
（２）スルホンアミド基（−ＳＯ₂ＮＨ−Ｒ）
（３）活性イミド基
〔−ＳＯ₂ＮＨＣＯＲ、−ＳＯ₂ＮＨＳＯ₂Ｒ、−ＣＯＮＨＳＯ₂Ｒ〕
（４）カルボン酸基（−ＣＯ₂Ｈ）
（５）スルホン酸基（−ＳＯ₃Ｈ）
（６）リン酸基（−ＯＰＯ₃Ｈ₂）
【００７４】
上記（１）〜（６）中、Ａｒは置換基を有していてもよい２価のアリール連結基を表し、Ｒは、置換基を有していてもよい炭化水素基を表す。
【００７５】
上記（１）〜（６）より選ばれる酸性基を有するアルカリ可溶性樹脂の中でも、（１）フェノール基、（２）スルホンアミド基および（３）活性イミド基を有するアルカリ可溶性樹脂が好ましく、特に、（１）フェノール基または（２）スルホンアミド基を有するアルカリ可溶性樹脂が、アルカリ性現像液に対する溶解性、現像ラチチュード、膜強度を充分に確保する点から最も好ましい。
【００７６】
上記（１）〜（６）より選ばれる酸性基を有するアルカリ可溶性樹脂としては、例えば、以下のものを挙げることができる。
（１）フェノール基を有するアルカリ可溶性樹脂としては、例えば、フェノールとホルムアルデヒドとの縮重合体、ｍ−クレゾールとホルムアルデヒドとの縮重合体、ｐ−クレゾールとホルムアルデヒドとの縮重合体、ｍ−／ｐ−混合クレゾールとホルムアルデヒドとの縮重合体、フェノールとクレゾール（ｍ−、ｐ−、またはｍ−／ｐ−混合のいずれでもよい）とホルムアルデヒドとの縮重合体等のノボラック樹脂、およびピロガロールとアセトンとの縮重合体を挙げることができる。さらに、フェノール基を側鎖に有する化合物を共重合させた共重合体を挙げることもできる。或いは、フェノール基を側鎖に有する化合物を共重合させた共重合体を用いることもできる。
【００７７】
フェノール基を有する化合物としては、フェノール基を有するアクリルアミド、メタクリルアミド、アクリル酸エステル、メタクリル酸エステル、またはヒドロキシスチレン等が挙げられる。
【００７８】
（２）スルホンアミド基を有するアルカリ可溶性樹脂としては、例えば、スルホンアミド基を有する化合物に由来する最小構成単位を主要構成成分として構成される重合体を挙げることができる。上記のような化合物としては、窒素原子に少なくとも一つの水素原子が結合したスルホンアミド基と、重合可能な不飽和基と、を分子内にそれぞれ１以上有する化合物が挙げられる。中でも、アクリロイル基、アリル基、またはビニロキシ基と、置換あるいはモノ置換アミノスルホニル基または置換スルホニルイミノ基と、を分子内に有する低分子化合物が好ましく、例えば、下記一般式（ｉ）〜一般式（ｖ）で表される化合物が挙げられる。
【００７９】
【化１１】

【００８０】
〔式中、Ｘ¹、Ｘ²は、それぞれ独立に−Ｏ−または−ＮＲ⁷を表す。Ｒ¹、Ｒ⁴は、それぞれ独立に水素原子またはＣＨ₃を表す。Ｒ²、Ｒ⁵、Ｒ⁹、Ｒ¹²、および、Ｒ¹⁶は、それぞれ独立に置換基を有していてもよい炭素数１〜１２のアルキレン基、シクロアルキレン基、アリーレン基またはアラルキレン基を表す。Ｒ³、Ｒ⁷、および、Ｒ¹³は、それぞれ独立に水素原子、置換基を有していてもよい炭素数１〜１２のアルキル基、シクロアルキル基、アリール基またはアラルキル基を表す。また、Ｒ⁶、Ｒ¹⁷は、それぞれ独立に置換基を有していてもよい炭素数１〜１２のアルキル基、シクロアルキル基、アリール基、アラルキル基を表す。Ｒ⁸、Ｒ¹⁰、Ｒ¹⁴は、それぞれ独立に水素原子またはＣＨ₃を表す。Ｒ¹¹、Ｒ¹⁵は、それぞれ独立に単結合または置換基を有していてもよい炭素数１〜１２のアルキレン基、シクロアルキレン基、アリーレン基またはアラルキレン基を表す。Ｙ¹、Ｙ²は、それぞれ独立に単結合またはＣＯを表す。〕
【００８１】
一般式（ｉ）〜一般式（ｖ）で表される化合物のうち、本発明の記録層では、特に、ｍ−アミノスルホニルフェニルメタクリレート、Ｎ−（ｐ−アミノスルホニルフェニル）メタクリルアミド、Ｎ−（ｐ−アミノスルホニルフェニル）アクリルアミド等を好適に使用することができる。
【００８２】
（３）活性イミド基を有するアルカリ可溶性樹脂としては、例えば、活性イミド基を有する化合物に由来する最小構成単位を主要構成成分として構成される重合体を挙げることができる。上記のような化合物としては、下記構造式で表される活性イミド基と、重合可能な不飽和基と、を分子内にそれぞれ１以上有する化合物を挙げることができる。
【００８３】
【化１２】

【００８４】
具体的には、Ｎ−（ｐ−トルエンスルホニル）メタクリルアミド、Ｎ−（ｐ−トルエンスルホニル）アクリルアミド等を好適に使用することができる。
【００８５】
（４）カルボン酸基を有するアルカリ可溶性樹脂としては、例えば、カルボン酸基と重合可能な不飽和基とを分子内にそれぞれ１以上有する化合物に由来する最小構成単位を主要構成成分とする重合体を挙げることができる。
（５）スルホン酸基を有するアルカリ可溶性高分子としては、例えば、スルホン酸基と重合可能な不飽和基とを分子内にそれぞれ１以上有する化合物に由来する最小構成単位を主要構成単位とする重合体を挙げることができる。
（６）リン酸基を有するアルカリ可溶性樹脂としては、例えば、リン酸基と重合可能な不飽和基とを分子内にそれぞれ１以上有する化合物に由来する最小構成単位を主要構成成分とする重合体を挙げることができる。
【００８６】
本発明の記録層に用いるアルカリ可溶性樹脂を構成する、前記（１）〜（６）より選ばれる酸性基を有する最小構成単位は、特に１種類のみである必要はなく、同一の酸性基を有する最小構成単位を２種以上、または異なる酸性基を有する最小構成単位を２種以上共重合させたものを用いることもできる。
【００８７】
前記共重合体は、共重合させる（１）〜（６）より選ばれる酸性基を有する化合物が共重合体中に１０モル％以上含まれているものが現像ラチチュードを充分に向上させるために好ましく、２０モル％以上含まれているものがより好ましい。
【００８８】
本発明では、化合物を共重合してアルカリ可溶性樹脂を共重合体として用いる場合、共重合させる化合物として、前記（１）〜（６）の酸性基を含まない他の化合物を用いることもできる。（１）〜（６）の酸性基を含まない他の化合物の例としては、下記（ｍ１）〜（ｍ１２）に挙げる化合物を例示することができるが、これらに限定されるものではない。
（ｍ１）２−ヒドロキシエチルアクリレートまたは２−ヒドロキシエチルメタクリレート等の脂肪族水酸基を有するアクリル酸エステル類、およびメタクリル酸エステル類。
（ｍ２）アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ブチル、アクリル酸アミル、アクリル酸ヘキシル、アクリル酸オクチル、アクリル酸ベンジル、アクリル酸−２−クロロエチル、グリシジルアクリレート、等のアルキルアクリレート。
（ｍ３）メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ブチル、メタクリル酸アミル、メタクリル酸ヘキシル、メタクリル酸シクロヘキシル、メタクリル酸ベンジル、メタクリル酸−２−クロロエチル、グリシジルメタクリレート、等のアルキルメタクリレート。
（ｍ４）アクリルアミド、メタクリルアミド、Ｎ−メチロールアクリルアミド、Ｎ−エチルアクリルアミド、Ｎ−ヘキシルメタクリルアミド、Ｎ−シクロヘキシルアクリルアミド、Ｎ−ヒドロキシエチルアクリルアミド、Ｎ−フェニルアクリルアミド、Ｎ−ニトロフェニルアクリルアミド、Ｎ−エチル−Ｎ−フェニルアクリルアミド等のアクリルアミド若しくはメタクリルアミド。
【００８９】
（ｍ５）エチルビニルエーテル、２−クロロエチルビニルエーテル、ヒドロキシエチルビニルエーテル、プロピルビニルエーテル、ブチルビニルエーテル、オクチルビニルエーテル、フェニルビニルエーテル等のビニルエーテル類。
（ｍ６）ビニルアセテート、ビニルクロロアセテート、ビニルブチレート、安息香酸ビニル等のビニルエステル類。
（ｍ７）スチレン、α−メチルスチレン、メチルスチレン、クロロメチルスチレン等のスチレン類。
（ｍ８）メチルビニルケトン、エチルビニルケトン、プロピルビニルケトン、フェニルビニルケトン等のビニルケトン類。
（ｍ９）エチレン、プロピレン、イソブチレン、ブタジエン、イソプレン等のオレフィン類。
（ｍ１０）Ｎ−ビニルピロリドン、アクリロニトリル、メタクリロニトリル等。
（ｍ１１）マレイミド、Ｎ−アクリロイルアクリルアミド、Ｎ−アセチルメタクリルアミド、Ｎ−プロピオニルメタクリルアミド、Ｎ−（ｐ−クロロベンゾイル）メタクリルアミド等の不飽和イミド。
（ｍ１２）アクリル酸、メタクリル酸、無水マレイン酸、イタコン酸等の不飽和カルボン酸。
【００９０】
アルカリ可溶性樹脂としては、赤外線レーザ等による露光での画像形成性に優れる点で、フェノール性水酸基を有することが好ましく、例えば、フェノールホルムアルデヒド樹脂、ｍ−クレゾールホルムアルデヒド樹脂、ｐ−クレゾールホルムアルデヒド樹脂、ｍ−／ｐ−混合クレゾールホルムアルデヒド樹脂、フェノール／クレゾール（ｍ−，ｐ−，またはｍ−／ｐ−混合のいずれでもよい）混合ホルムアルデヒド樹脂等のノボラック樹脂やピロガロールアセトン樹脂が好ましく挙げられる。
【００９１】
また、フェノール性水酸基を有するアルカリ可溶性樹脂としては、更に、米国特許第４，１２３，２７９号明細書に記載されているように、ｔ−ブチルフェノールホルムアルデヒド樹脂、オクチルフェノールホルムアルデヒド樹脂のような、炭素数３〜８のアルキル基を置換基として有するフェノールとホルムアルデヒドとの縮重合体が挙げられる。
【００９２】
アルカリ可溶性樹脂は、その重量平均分子量が５００以上であることが画像形成性の点で好ましく、１，０００〜７００，０００であることがより好ましい。また、その数平均分子量が５００以上であることが好ましく、７５０〜６５０，０００であることがより好ましい。分散度（重量平均分子量／数平均分子量）は１．１〜１０であることが好ましい。
【００９３】
また、これらのアルカリ可溶性樹脂は単独で用いるのみならず、２種類以上を組み合わせて使用してもよい。組み合わせる場合には、米国特許第４１２３２７９号明細書に記載されているような、ｔ−ブチルフェノールとホルムアルデヒドとの縮重合体や、オクチルフェノールとホルムアルデヒドとの縮重合体のような、炭素数３〜８のアルキル基を置換基として有するフェノールとホルムアルデヒドとの縮重合体、本発明者らが先に提出した特開２０００−２４１９７２号公報に記載の芳香環上に電子吸引性基を有するフェノール構造を有するアルカリ可溶性樹脂などを併用してもよい。
【００９４】
本発明におけるアルカリ可溶性樹脂は、その合計の含有量が、記録層の全固形分中、３０〜９８質量％が好ましく、４０〜９５質量％がより好ましい。含有量が３０質量％以上であることで、耐久性を充分に確保でき、また、９８質量％以下とすることで、感度、画像形成性を充分に確保できるので好ましい。
【００９５】
＜（Ｂ）赤外線吸収剤＞
本発明に用いられる赤外線吸収剤としては、赤外線を吸収し、熱を発生する物質であれば特に制限はなく用いることができるが、入手容易な高出力レーザへの適合性の観点から、波長７６０ｎｍ〜１２００ｎｍに吸収極大を有する赤外線吸収性染料または顔料が好ましく挙げられる。
【００９６】
染料としては、市販の染料、例えば「染料便覧」（有機合成化学協会編集、昭和４５年刊）等の文献に記載されている公知のものが利用できる。具体的には、アゾ染料、金属錯塩アゾ染料、ピラゾロンアゾ染料、ナフトキノン染料、アントラキノン染料、フタロシアニン染料、カルボニウム染料、キノンイミン染料、メチン染料、シアニン染料、スクアリリウム色素、ピリリウム塩、金属チオレート錯体、オキソノール染料、ジイモニウム染料、アミニウム染料、クロコニウム染料等の染料が挙げられる。
【００９７】
好ましい染料としては、例えば、特開昭５８−１２５２４６号、特開昭５９−８４３５６号、特開昭６０−７８７８７号、米国特許第４９７３５７２号明細書等に記載されているシアニン染料、特開昭５８−１７３６９６号、特開昭５８−１８１６９０号、特開昭５８−１９４５９５号等に記載されているメチン染料、特開昭５８−１１２７９３号、特開昭５８−２２４７９３号、特開昭５９−４８１８７号、特開昭５９−７３９９６号、特開昭６０−５２９４０号、特開昭６０−６３７４４号等に記載されているナフトキノン染料、特開昭５８−１１２７９２号等に記載されているスクアリリウム色素、英国特許４３４，８７５号記載のシアニン染料等を挙げることができる。
【００９８】
また、米国特許第５，１５６，９３８号記載の近赤外吸収増感剤も好適に用いられ、また、米国特許第３，８８１，９２４号記載の置換されたアリールベンゾ（チオ）ピリリウム塩、特開昭５７−１４２６４５号（米国特許第４，３２７，１６９号）記載のトリメチンチアピリリウム塩、特開昭５８−１８１０５１号、同５８−２２０１４３号、同５９−４１３６３号、同５９−８４２４８号、同５９−８４２４９号、同５９−１４６０６３号、同５９−１４６０６１号に記載されているピリリウム系化合物、特開昭５９−２１６１４６号記載のシアニン色素、米国特許第４，２８３，４７５号に記載のペンタメチンチオピリリウム塩等や特公平５−１３５１４号、同５−１９７０２号に開示されているピリリウム化合物も好ましく用いられる。
【００９９】
また、染料として好ましい別の例として米国特許第４，７５６，９９３号明細書中に式（Ｉ）、（II）として記載されている近赤外吸収染料を挙げることができる。
【０１００】
これらの染料のうち特に好ましいものとしては、シアニン色素、フタロシアニン染料、オキソノール染料、スクアリリウム色素、ピリリウム塩、チオピリリウム染料、ニッケルチオレート錯体が挙げられる。さらに、下記一般式（ａ）〜一般式（ｅ）で示される染料が光熱変換効率に優れるため好ましく、特に下記一般式（ａ）で示されるシアニン色素は、本発明の記録層で使用した場合に、アルカリ溶解性樹脂との高い相互作用を与え、且つ、安定性、経済性に優れるため最も好ましい。
【０１０１】
【化１３】

【０１０２】
一般式（ａ）中、Ｘ¹は、水素原子、ハロゲン原子、−ＮＰｈ₂、Ｘ²−Ｌ¹または以下に示す基を表す。ここで、Ｘ²は酸素原子または、硫黄原子を示し、Ｌ¹は、炭素原子数１〜１２の炭化水素基、ヘテロ原子を有する芳香族環、ヘテロ原子を含む炭素原子数１〜１２の炭化水素基を示す。なお、ここでヘテロ原子とは、Ｎ、Ｓ、Ｏ、ハロゲン原子、Ｓｅを示す。
【０１０３】
【化１４】

【０１０４】
Ｒ¹およびＲ²は、それぞれ独立に、炭素原子数１〜１２の炭化水素基を示す。記録層塗布液の保存安定性から、Ｒ¹およびＲ²は、炭素原子数２個以上の炭化水素基であることが好ましく、さらに、Ｒ¹とＲ²とは互いに結合し、５員環または６員環を形成していることが特に好ましい。
【０１０５】
Ａｒ¹、Ａｒ²は、それぞれ同じでも異なっていても良く、置換基を有していても良い芳香族炭化水素基を示す。好ましい芳香族炭化水素基としては、ベンゼン環およびナフタレン環が挙げられる。また、好ましい置換基としては、炭素原子数１２個以下の炭化水素基、ハロゲン原子、炭素原子数１２個以下のアルコキシ基が挙げられる。Ｙ¹、Ｙ²は、それぞれ同じでも異なっていても良く、硫黄原子または炭素原子数１２個以下のジアルキルメチレン基を示す。Ｒ³、Ｒ⁴は、それぞれ同じでも異なっていても良く、置換基を有していても良い炭素原子数２０個以下の炭化水素基を示す。好ましい置換基としては、炭素原子数１２個以下のアルコキシ基、カルボキシル基、スルホ基が挙げられる。Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸は、それぞれ同じでも異なっていても良く、水素原子または炭素原子数１２個以下の炭化水素基を示す。原料の入手性から、好ましくは水素原子である。また、Ｚａ^-は、対アニオンを示す。ただし、Ｒ¹〜Ｒ⁸のいずれかにスルホ基が置換されている場合は、Ｚａ^-は必要ない。好ましいＺａ^-は、記録層塗布液の保存安定性から、ハロゲンイオン、過塩素酸イオン、テトラフルオロボレートイオン、ヘキサフルオロホスフェートイオン、およびスルホン酸イオンであり、特に好ましくは、過塩素酸イオン、ヘキサフルオロホスフェートイオン、およびアリールスルホン酸イオンである。
【０１０６】
本発明において、好適に用いることのできる一般式（ａ）で示されるシアニン色素の具体例としては、以下に例示するものの他、特開２００１−１３３９６９明細書の段落番号［００１７］〜［００１９］、特開２００２−４０６３８明細書の段落番号［００１２］〜［００３８］、特開２００２−２３３６０明細書の段落番号［００１２］〜［００２３］に記載されたものを挙げることができる。
【０１０７】
【化１５】

【０１０８】
【化１６】

【０１０９】
【化１７】

【０１１０】
【化１８】

【０１１１】
前記一般式（ｂ）中、Ｌは共役炭素原子数７以上のメチン鎖を表し、該メチン鎖は置換基を有していてもよく、置換基が互いに結合して環構造を形成していてもよい。Ｚｂ⁺は対カチオンを示す。好ましい対カチオンとしては、アンモニウム、ヨードニウム、スルホニウム、ホスホニウム、ピリジニウム、アルカリ金属カチオン（Ｎｉ⁺、Ｋ⁺、Ｌｉ⁺）などが挙げられる。Ｒ⁹〜Ｒ¹⁴およびＲ¹⁵〜Ｒ²⁰は互いに独立に水素原子またはハロゲン原子、シアノ基、アルキル基、アリール基、アルケニル基、アルキニル基、カルボニル基、チオ基、スルホニル基、スルフィニル基、オキシ基、またはアミノ基から選択される置換基、或いは、これらを２つ若しくは３つ組み合わせた置換基を表し、互いに結合して環構造を形成していてもよい。ここで、前記一般式（ｂ）中、Ｌが共役炭素原子数７のメチン鎖を表すもの、および、Ｒ⁹〜Ｒ¹⁴およびＲ¹⁵〜Ｒ²⁰がすべて水素原子を表すものが入手の容易性と効果の観点から好ましい。
【０１１２】
本発明において、好適に用いることのできる一般式（ｂ）で示される染料の具体例としては、以下に例示するものを挙げることができる。
【０１１３】
【化１９】

【０１１４】
【化２０】

【０１１５】
前記一般式（ｃ）中、Ｙ³およびＹ⁴は、それぞれ、酸素原子、硫黄原子、セレン原子、またはテルル原子を表す。Ｍは、共役炭素数５以上のメチン鎖を表す。Ｒ²¹〜Ｒ²⁴およびＲ²⁵〜Ｒ²⁸は、それぞれ同じであっても異なっていてもよく、水素原子、ハロゲン原子、シアノ基、アルキル基、アリール基、アルケニル基、アルキニル基、カルボニル基、チオ基、スルホニル基、スルフィニル基、オキシ基、またはアミノ基を表す。また、式中Ｚａ^-は対アニオンを表し、前記一般式（ａ）におけるＺａ^-と同義である。
【０１１６】
本発明において、好適に用いることのできる一般式（ｃ）で示される染料の具体例としては、以下に例示するものを挙げることができる。
【０１１７】
【化２１】

【０１１８】
【化２２】

【０１１９】
前記一般式（ｄ）中、Ｒ²⁹〜Ｒ³²は各々独立に、水素原子、アルキル基、またはアリール基を示す。Ｒ³³およびＲ³⁴は各々独立に、アルキル基、置換オキシ基、またはハロゲン原子を示す。ｎおよびｍは各々独立に０ないし４の整数を示す。Ｒ²⁹とＲ³⁰、またはＲ³¹とＲ³²はそれぞれ結合して環を形成してもよく、またＲ²⁹および／またはＲ³⁰はＲ³³と、またＲ³¹および／またはＲ³²はＲ³⁴と結合して環を形成しても良く、さらに、Ｒ³³或いはＲ³⁴が複数存在する場合に、Ｒ³³同士あるいはＲ³⁴同士は互いに結合して環を形成してもよい。Ｘ²およびＸ³は各々独立に、水素原子、アルキル基、またはアリール基であり、Ｘ²およびＸ³の少なくとも一方は水素原子またはアルキル基を示す。Ｑは置換基を有していてもよいトリメチン基またはペンタメチン基であり、２価の有機基とともに環構造を形成してもよい。Ｚｃ^-は対アニオンを示し、前記一般式（ａ）におけるＺａ^-と同義である。
【０１２０】
本発明において、好適に用いることのできる一般式（ｄ）で示される染料の具体例としては、以下に例示するものを挙げることができる。
【０１２１】
【化２３】

【０１２２】
【化２４】

【０１２３】
前記一般式（ｅ）中、Ｒ³⁵〜Ｒ⁵⁰はそれぞれ独立に、置換基を有してもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アリール基、アルケニル基、アルキニル基、水酸基、カルボニル基、チオ基、スルホニル基、スルフィニル基、オキシ基、アミノ基、オニウム塩構造を示す。Ｒ³⁶とＲ³⁷、Ｒ⁴⁰とＲ⁴¹、Ｒ⁴⁴とＲ⁴⁵およびＲ⁴⁸とＲ⁴⁹は、連結して脂肪族環、芳香族環または複素環を形成してもよく、その環は縮合環を有してもよい。Ｍは２つの水素原子若しくは金属原子、ハロメタル基、オキシメタル基を示すが、そこに含まれる金属原子としては、周期律表のＩＡ、IIＡ、IIIＢ、IVＢ族原子、第一、第二、第三周期の遷移金属、ランタノイド元素が挙げられ、中でも、銅、マグネシウム、鉄、亜鉛、コバルト、アルミニウム、チタン、バナジウムが好ましい。
【０１２４】
本発明において、好適に用いることのできる一般式（ｅ）で示される染料の具体例としては、以下に例示するものを挙げることができる。
【０１２５】
【化２５】

【０１２６】
本発明において赤外線吸収剤として使用される顔料としては、市販の顔料およびカラーインデックス（Ｃ．Ｉ．）便覧、「最新顔料便覧」（日本顔料技術協会編、１９７７年刊）、「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）、「印刷インキ技術」ＣＭＣ出版、１９８４年刊）に記載されている顔料が挙げられる。
【０１２７】
顔料の種類としては、黒色顔料、黄色顔料、オレンジ色顔料、褐色顔料、赤色顔料、紫色顔料、青色顔料、緑色顔料、蛍光顔料、金属粉顔料、その他、ポリマー結合色素が挙げられる。具体的には、不溶性アゾ顔料、アゾレーキ顔料、縮合アゾ顔料、キレートアゾ顔料、フタロシアニン系顔料、アントラキノン系顔料、ペリレンおよびペリノン系顔料、チオインジゴ系顔料、キナクリドン系顔料、ジオキサジン系顔料、イソインドリノン系顔料、キノフタロン系顔料、染付けレーキ顔料、アジン顔料、ニトロソ顔料、ニトロ顔料、天然顔料、蛍光顔料、無機顔料、カーボンブラック等が使用できる。これらの顔料のうち好ましいものはカーボンブラックである。
【０１２８】
これら顔料は表面処理をせずに用いてもよく、表面処理を施して用いてもよい。表面処理の方法には、樹脂やワックスを表面コートする方法、界面活性剤を付着させる方法、反応性物質（例えば、シランカップリング剤、エポキシ化合物、ポリイソシアネート等）を顔料表面に結合させる方法等が考えられる。上記の表面処理方法は、「金属石鹸の性質と応用」（幸書房）、「印刷インキ技術」（ＣＭＣ出版、１９８４年刊）および「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）に記載されている。
【０１２９】
顔料の粒径は０．０１μｍ〜１０μｍの範囲にあることが好ましく、０．０５μｍ〜１μｍの範囲にあることがさらに好ましく、特に０．１μｍ〜１μｍの範囲にあることが好ましい。分散物の画像記録層塗布液中での安定性の点から顔料の粒径は０．０１μｍ以上であることが好ましく、また、記録層の均一性の点から１０μｍ以下であることが好ましい。
【０１３０】
顔料を分散する方法としては、インク製造やトナー製造等に用いられる公知の分散技術が使用できる。分散機としては、超音波分散器、サンドミル、アトライター、パールミル、スーパーミル、ボールミル、インペラー、デスパーザー、ＫＤミル、コロイドミル、ダイナトロン、３本ロールミル、加圧ニーダー等が挙げられる。詳細は、「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）に記載されている。
【０１３１】
これらの顔料もしくは染料は、記録層の全固形分に対し０．０１〜５０質量％、好ましくは０．１〜１０質量％、染料の場合特に好ましくは０．５〜１０質量％、顔料の場合特に好ましくは０．１〜１０質量％の割合で添加することができる。顔料もしくは染料の添加量が０．０１質量％以上とすることで感度を充分に確保することができ、また５０質量％以下の範囲とすることで、記録層の均一性や、記録層の膜強度を維持できる。
【０１３２】
［ポジ型の記録層］
上記の本発明の記録層は、赤外線レーザ露光によりアルカリ水溶液に対する溶解性が向上するポジ型記録層として平版印刷版原版に適用される。ポジ型記録層としては、相互作用解除系の記録層および酸触媒分解系の記録層が挙げられる。これらの記録層は多層構成で用いることができる。例えば、相互作用解除系２層からなる記録層、相互作用系と酸触媒分解系とからなる２層構成などが挙げられる。酸触媒分解系が、多層構造内の一層として複数の層中に設けられる場合には、特に、露光面の最上層として形成されることが好ましい。
【０１３３】
＜相互作用解除系＞
相互作用解除系の記録層は、（Ａ）アルカリ可溶性樹脂と（Ｂ）赤外線吸収剤とを含む層であり、光照射や加熱により発生する熱エネルギーにより、記録層を形成しているアルカリ可溶性樹脂の会合などの相互作用が解除されてアルカリ水溶液に可溶となり、現像により除去されて非画像部を形成するものである。その際、本発明の（Ｃ）チオール化合物を共存させることによって、良好なディスクリミネーションが付与される。
本発明の相互作用解除系の記録層には、所望により上記（Ａ）、（Ｂ）および（Ｃ）成分以外の公知の化合物を併用することができる。
【０１３４】
＜酸触媒分解系＞
酸触媒分解系の記録層は、上記（Ａ）、（Ｂ）および（Ｃ）成分の他に、光または熱の作用により酸を発生する化合物（酸発生剤）、および、発生した酸を触媒として化学結合を開裂しアルカリ現像液に対する溶解性が増大する化合物（酸分解性化合物）とを必須成分として含有する層である。この系では、（Ａ）アルカリ可溶性樹脂は主としてバインダーポリマーとして機能する。
かかる酸触媒分解のメカニズムにより、酸触媒分解系画像形成材料は、化学増幅系画像形成材料とも称される。
【０１３５】
＜酸分解性化合物＞
本発明において、酸を触媒として化学結合を開裂しアルカリ現像液に対する溶解性が増大する化合物とは、分子内に酸で分解し得る結合基を有する化合物と言い代えることができる。このような化合物は、特開平９−１７１２５４号公報に「酸で分解し得る結合を少なくとも１つ有する化合物」として記載されたものを用いることができる。酸で分解し得る結合としては、例えば、アセタール結合またはケタール結合等を好ましいものとして挙げることができる。
このような化合物中、感度および現像性の観点から、下記一般式（Ｉ）で表される化合物を用いることがより好ましい。
【０１３６】
【化２６】

【０１３７】
一般式（Ｉ）中、Ｒ¹、Ｒ²およびＲ³は、各々水素原子、炭素原子数１〜５のアルキル基、炭素原子数１〜５のアルコキシ基、スルホ基、カルボキシル基またはヒドロキシル基を表し、ｐ、ｑおよびｒは、各々１〜３の整数を表し、ｍおよびｎは、各々１〜５の整数を表す。
【０１３８】
一般式（Ｉ）において、Ｒ¹、Ｒ²およびＲ³が表すアルキル基は直鎖でも分岐でもよく、例えばメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔｅｒｔ−ブチル基、ペンチル基等が挙げられ、アルコキシ基としては、例えばメトキシ基、エトキシ基、プロポキシ基、イソプロポキシ基、ブトキシ基、ｔｅｒｔ−ブトキシ基、ペントキシ基等が挙げられ、スルホ基およびカルボキシル基はその塩を包含する。一般式（Ｉ）で表される化合物のうち、ｍおよびｎが１または２である化合物が特に好ましい。一般式（Ｉ）で表される化合物は公知の方法で合成することができる。
【０１３９】
その他、本発明に適用し得る酸分解性化合物としては、特開昭４８−８９６０３号、同５１−１２０７１４号、同５３−１３３４２９号、同５５−１２９９５号、同５５−１２６２３６号、同５６−１７３４５号に記載のＣ−Ｏ−Ｃ結合を有する化合物、特開昭６０−３７５４９号、同６０−１２１４４６号に記載のＳｉ−Ｏ−Ｃ結合を有する化合物、特開昭６０−３６２５号、同６０−１０２４７号に記載されているその他の酸分解化合物を挙げることができ、更に特開昭６２−２２２２４６号に記載されているＳｉ−Ｎ結合を有する化合物、特開昭６２−２５１７４３号に記載されている炭酸エステル、特開昭６２−２０９４５１号に記載されているオルト炭酸エステル、特開昭６２−２８０８４１号に記載されているオルトチタン酸エステル、特開昭６２−２８０８４２号に記載されているオルトケイ酸エステル、特開昭６３−０１０１５３号、特開平１０−５５０６７号、同１０−１１１５６４号、同１０−８７７３３号、同１０−１５３８５３号、同１０−２２８１０２号、同１０−２６８５０７号、同２８２６４８号、同１０−２８２６７０号、ＥＰ−０８８４５４７Ａｌに記載されているアセタール、ケタールおよびオルトカルボン酸エステル、特開昭６２−２４４０３８号に記載されているＣ−Ｓ結合を有する化合物を用いることが出来る。
【０１４０】
上記酸分解性化合物の中でも特に、特開昭５３−１３３４２９号、同５６−１７３４５号、同６０−１２１４４６号、同６０−３７５４９号、同６２−２０９４５１号、同６３−０１０１５３号、特開平１０−５５０６７号、同１０−１１１５６４号、同１０−８７７３３号、同１０−１５３８５３号、同１０−２２８１０２号、同１０−２６８５０７号、同２８２６４８号、同１０−２８２６７０号、ＥＰ０８８４６４７Ａｌの各公報に記載されているＣ−Ｏ−Ｃ結合を有する化合物、Ｓｉ−Ｏ−Ｃ結合を有する化合物、オルト炭酸エステル、アセタール類、ケタール類およびシリルエーテル類が好ましい。
この酸分解性化合物の中でも、主鎖中に繰り返しアセタールまたはケタール部分を有し、アルカリ現像液中でその溶解度が発生した酸により上昇する高分子化合物が好ましく用いられる。
【０１４１】
これらの酸分解性化合物は、１種のみを用いても、２種以上を組み合わせて用いてもよい。また、添加量としては、化学増幅層全固形分に対し５〜７０質量％、好ましくは１０〜５０質量％、より好ましくは１５〜３５質量％の割合で層中に添加される。添加量が５質量％以上とすることで、非画像部の汚れが発生せず、また添加量が７０質量％以下とすることで、画像部の膜強度を保つことができるために好ましい。
【０１４２】
＜酸発生剤＞
光または熱により酸を発生する化合物（酸発生剤）とは、赤外線の照射や、１００℃以上の加熱によって分解し酸を発生する化合物を指す。発生する酸としては、スルホン酸、塩酸等のｐＫａが２以下の強酸であることが好ましい。
【０１４３】
本発明において好適に用いられる酸発生剤としては、ヨードニウム塩、スルホニウム塩、ホスホニウム塩、ジアゾニウム塩等のオニウム塩が挙げられる。具体的には、米国特許第４，７０８，９２５号明細書や特開平７−２０６２９号公報に記載されている化合物を挙げることができる。特に、スルホン酸イオンを対イオンとするヨードニウム塩、スルホニウム塩、ジアゾニウム塩が好ましい。ジアゾニウム塩としては、米国特許第３，８６７，１４７号記載のジアゾニウム化合物、米国特許第２，６３２，７０３号明細書記載のジアゾニウム化合物や特開平１−１０２４５６号公報および特開平１−１０２４５７号公報に記載されているジアゾ樹脂も好ましい。また、米国特許第５，１３５，８３８号明細書や米国特許第５，２００，５４４号明細書に記載されているベンジルスルホナート類も好ましい。更に、特開平２−１０００５４号公報、特開平２−１０００５５号公報および特開平９−１９７６７１号公報に記載されている活性スルホン酸エステルやジスルホニル化合物類も好ましい。他にも、特開平７−２７１０２９号公報に記載されている、ハロアルキル置換されたＳ−トリアジン類も好ましい。
【０１４４】
本発明における光酸発生剤の含有量は、その化学的性質および本発明の記録層の組成あるいは物性によって広範囲に変えることができるが、記録層固形分に対して約０．１〜約２０質量％の範囲が適当であり、好ましくは０．２〜１０質量％の範囲である。
【０１４５】
＜その他の成分＞
上述された本発明の記録層には、更に必要に応じて、種々の添加剤を添加することができる。
例えば、他のオニウム塩、芳香族スルホン化合物、芳香族スルホン酸エステル化合物、多官能アミン化合物等、添加するとアルカリ水可溶性高分子（アルカリ可溶性樹脂）の現像液への溶解阻止機能を向上させるいわゆる溶解抑止剤を添加することが好ましく、中でも、オニウム塩、ｏ−キノンジアジド化合物、スルホン酸アルキルエステル等の熱分解性であり、分解しない状態ではアルカリ可溶性樹脂の溶解性を実質的に低下させる物質を併用することが、画像部の現像液への溶解阻止性の向上を図る点で好ましい。分解性溶解抑止剤としては、ジアゾニウム塩、ヨードニウム塩、スルホニウム塩、アンモニウム塩等のオニウム塩および、ｏ−キノンジアジド化合物が好ましく、ジアゾニウム塩、ヨードニウム塩、スルホニウム塩のオニウム塩がより好ましい。
【０１４６】
本発明において用いられるオニウム塩として、好適なものとしては、例えばＳ．Ｉ．Ｓｃｈｌｅｓｉｎｇｅｒ，Ｐｈｏｔｏｇｒ．Ｓｃｉ．Ｅｎｇ．，１８，３８７（１９７４）、Ｔ．Ｓ．Ｂａｌ ｅｔ ａｌ，Ｐｏｌｙｍｅｒ，２１，４２３（１９８０）、特開平５−１５８２３０号公報に記載のジアゾニウム塩、米国特許第４，０６９，０５５号、同４，０６９，０５６号、特開平３−１４０１４０号の明細書に記載のアンモニウム塩、Ｄ．Ｃ．Ｎｅｃｋｅｒ ｅｔ ａｌ，Ｍａｃｒｏｍｏｌｅｃｕｌｅｓ，１７，２４６８（１９８４）、Ｃ．Ｓ．Ｗｅｎ ｅｔ ａｌ，Ｔｅｈ，Ｐｒｏｃ．Ｃｏｎｆ．Ｒａｄ．Ｃｕｒｉｎｇ ＡＳＩＡ，ｐ４７８ Ｔｏｋｙｏ，Ｏｃｔ（１９８８）、米国特許第４，０６９，０５５号、同４，０６９，０５６号に記載のホスホニウム塩、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏｅｔ ａｌ，Ｍａｃｒｏｍｏｒｅｃｕｌｅｓ，１０（６），１３０７（１９７７）、Ｃｈｅｍ．＆Ｅｎｇ．Ｎｅｗｓ，Ｎｏｖ．２８，ｐ３１（１９８８）、欧州特許第１０４，１４３号、米国特許第５，０４１，３５８号、同第４，４９１，６２８号、特開平２−１５０８４８号、特開平２−２９６５１４号に記載のヨードニウム塩、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，Ｐｏｌｙｍｅｒ Ｊ．１７，７３（１９８５）、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ．Ｊ．Ｏｒｇ．Ｃｈｅｍ．，４３，３０５５（１９７８）、Ｗ．Ｒ．Ｗａｔｔ ｅｔ ａｌ，Ｊ．Ｐｏｌｙｍｅｒ Ｓｃｉ．，Ｐｏｌｙｍｅｒ Ｃｈｅｍ．Ｅｄ．，２２，１７８９（１９８４）、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，ＰｏｌｙｍｅｒＢｕｌｌ．，１４，２７９（１９８５）、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，Ｍａｃｒｏｍｏｒｅｃｕｌｅｓ，１４（５），１１４１（１９８１）、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，Ｊ．Ｐｏｌｙｍｅｒ Ｓｃｉ．，Ｐｏｌｙｍｅｒ Ｃｈｅｍ．Ｅｄ．，１７，２８７７（１９７９）、欧州特許第３７０，６９３号、同２３３，５６７号、同２９７，４４３号、同２９７，４４２号、米国特許第４，９３３，３７７号、同３，９０２，１１４号、同５，０４１，３５８号、同４，４９１，６２８号、同４，７６０，０１３号、同４，７３４，４４４号、同２，８３３，８２７号、独国特許第２，９０４，６２６号、同３，６０４，５８０号、同３，６０４，５８１号に記載のスルホニウム塩、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，Ｍａｃｒｏｍｏｒｅｃｕｌｅｓ，１０（６），１３０７（１９７７）、Ｊ．Ｖ．Ｃｒｉｖｅｌｌｏ ｅｔ ａｌ，Ｊ．Ｐｏｌｙｍｅｒ Ｓｃｉ．，Ｐｏｌｙｍｅｒ Ｃｈｅｍ．Ｅｄ．，１７，１０４７（１９７９）に記載のセレノニウム塩、Ｃ．Ｓ．Ｗｅｎ ｅｔ ａｌ，Ｔｅｈ，Ｐｒｏｃ．Ｃｏｎｆ．Ｒａｄ．Ｃｕｒｉｎｇ ＡＳＩＡ，ｐ４７８ Ｔｏｋｙｏ，Ｏｃｔ（１９８８）に記載のアルソニウム塩等があげられる。
これらのオニウム塩の中でも、溶解阻止能や熱分解性の観点から、ジアゾニウム塩が特に好ましい。特に、特開平５−１５８２３０号公報に記載の一般式（Ｉ）で示されるジアゾニウム塩や特開平１１−１４３０６４号公報に記載の一般式（１）で示されるジアゾニウム塩が好ましく、可視光領域の吸収波長が小さい特開平１１−１４３０６４号公報に記載の一般式（１）で示されるジアゾニウム塩が最も好ましい。
【０１４７】
オニウム塩の対イオンとしては、四フッ化ホウ酸、六フッ化リン酸、トリイソプロピルナフタレンスルホン酸、５−ニトロ−ｏ−トルエンスルホン酸、５−スルホサリチル酸、２，５−ジメチルベンゼンスルホン酸、２，４，６−トリメチルベンゼンスルホン酸、２−ニトロベンゼンスルホン酸、３−クロロベンゼンスルホン酸、３−ブロモベンゼンスルホン酸、２−フルオロカプリルナフタレンスルホン酸、ドデシルベンゼンスルホン酸、１−ナフトール−５−スルホン酸、２−メトキシ−４−ヒドロキシ−５−ベンゾイル−ベンゼンスルホン酸、およびパラトルエンスルホン酸等を挙げることができる。これらの中でも特に六フッ化リン酸、トリイソプロピルナフタレンスルホン酸や２，５−ジメチルベンゼンスルホン酸のごときアルキル芳香族スルホン酸が好適である。
【０１４８】
好適なキノンジアジド類としてはｏ−キノンジアジド化合物を挙げることができる。本発明に用いられるｏ−キノンジアジド化合物は、少なくとも１個のｏ−キノンジアジド基を有する化合物で、熱分解によりアルカリ可溶性を増すものであり、種々の構造の化合物を用いることができる。つまり、ｏ−キノンジアジドは熱分解により結着剤の溶解抑制能を失うことと、ｏ−キノンジアジド自身がアルカリ可溶性の物質に変化することの両方の効果により感材系の溶解性を助ける。本発明に用いられるｏ−キノンジアジド化合物としては、例えば、Ｊ．コーサー著「ライト−センシティブ・システムズ」（Ｊｏｈｎ Ｗｉｌｅｙ＆Ｓｏｎｓ．Ｉｎｃ．）第３３９〜３５２頁に記載の化合物が使用できるが、特に種々の芳香族ポリヒドロキシ化合物あるいは芳香族アミノ化合物と反応させたｏ−キノンジアジドのスルホン酸エステルまたはスルホン酸アミドが好適である。また、特公昭４３−２８４０３号公報に記載されているようなベンゾキノン（１，２）−ジアジドスルホン酸クロライドまたはナフトキノン−（１，２）−ジアジド−５−スルホン酸クロライドとピロガロール−アセトン樹脂とのエステル、米国特許第３，０４６，１２０号および同第３，１８８，２１０号に記載されているベンゾキノン−（１，２）−ジアジドスルホン酸クロライドまたはナフトキノン−（１，２）−ジアジド−５−スルホン酸クロライドとフェノール−ホルムアルデヒド樹脂とのエステルも好適に使用される。
【０１４９】
さらにナフトキノン−（１，２）−ジアジド−４−スルホン酸クロライドとフェノールホルムアルデヒド樹脂あるいはクレゾール−ホルムアルデヒド樹脂とのエステル、ナフトキノン−（１，２）−ジアジド−４−スルホン酸クロライドとピロガロール−アセトン樹脂とのエステルも同様に好適に使用される。その他の有用なｏ−キノンジアジド化合物としては、数多くの特許に報告され知られている。例えば特開昭４７−５３０３号、特開昭４８−６３８０２号、特開昭４８−６３８０３号、特開昭４８−９６５７５号、特開昭４９−３８７０１号、特開昭４８−１３３５４号、特公昭４１−１１２２２号、特公昭４５−９６１０号、特公昭４９−１７４８１号、米国特許第２，７９７，２１３号、同第３，４５４，４００号、同第３，５４４，３２３号、同第３，５７３，９１７号、同第３，６７４，４９５号、同第３，７８５，８２５号、英国特許第１，２２７，６０２号、同第１，２５１，３４５号、同第１，２６７，００５号、同第１，３２９，８８８号、同第１，３３０，９３２号、ドイツ特許第８５４，８９０号などの各明細書中に記載されているものをあげることができる。
【０１５０】
分解性溶解抑止剤であるオニウム塩、および／または、ｏ−キノンジアジド化合物の添加量は好ましくは記録層の全固形分に対し、１〜１０質量％、更に好ましくは１〜５質量％、特に好ましくは１〜２質量％の範囲である。これらの化合物は単一で使用できるが、数種の混合物として使用してもよい。
【０１５１】
ｏ−キノンジアジド化合物以外の添加剤の添加量は、好ましくは０．１〜５質量％、更に好ましくは０．１〜２質量％、特に好ましくは０．１〜１．５質量％である。本発明に係る添加剤と結着剤は、同一層へ含有させることが好ましい。
【０１５２】
また、分解性を有さない溶解抑止剤を併用してもよく、好ましい溶解抑止剤としては、特開平１０−２６８５１２号公報に詳細に記載されているスルホン酸エステル、燐酸エステル、芳香族カルボン酸エステル、芳香族ジスルホン、カルボン酸無水物、芳香族ケトン、芳香族アルデヒド、芳香族アミン、芳香族エーテル等、同じく特開平１１−１９０９０３号公報に詳細に記載されているラクトン骨格、Ｎ，Ｎ−ジアリールアミド骨格、ジアリールメチルイミノ骨格を有し着色剤を兼ねた酸発色性色素、同じく特開２０００−１０５４５４号公報に詳細に記載されている非イオン性界面活性剤等を挙げることができる。
【０１５３】
また別の添加剤としては、感度を向上させる目的で、環状酸無水物類、フェノール類、有機酸類を併用することができる。また、後述する界面活性剤、画像着色剤、および、可塑剤も使用可能な添加剤である。
【０１５４】
環状酸無水物としては米国特許第４，１１５，１２８号明細書に記載されている無水フタル酸、テトラヒドロ無水フタル酸、ヘキサヒドロ無水フタル酸、３，６−エンドオキシ−Δ４−テトラヒドロ無水フタル酸、テトラクロル無水フタル酸、無水マレイン酸、クロル無水マレイン酸、α−フェニル無水マレイン酸、無水コハク酸、無水ピロメリット酸などが使用できる。フェノール類としては、ビスフェノールＡ、ｐ−ニトロフェノール、ｐ−エトキシフェノール、２，４，４'−トリヒドロキシベンゾフェノン、２，３，４−トリヒドロキシベンゾフェノン、４−ヒドロキシベンゾフェノン、４，４'，４''−トリヒドロキシトリフェニルメタン、４，４'，３''，４''−テトラヒドロキシ−３，５，３'，５'−テトラメチルトリフェニルメタンなどが挙げられる。更に、有機酸類としては、特開昭６０−８８９４２号、特開平２−９６７５５号公報などに記載されている、スルホン酸類、スルフィン酸類、アルキル硫酸類、ホスホン酸類、リン酸エステル類およびカルボン酸類などが挙げられる。
【０１５５】
上記の環状酸無水物、フェノール類および有機酸類の記録層中に占める割合は、０．０５〜２０質量％が好ましく、より好ましくは０．１〜１５質量％、特に好ましくは０．１〜１０質量％である。
【０１５６】
また、これら以外にも、本発明者らが先に提案した特開平１１−１６０８６０号公報に記載のアルカリ溶解抑制作用を有する架橋性化合物等を目的に応じて適宜添加することができる。
【０１５７】
また、本発明に係る記録層塗布液中には、現像条件に対する処理の安定性を広げるため、特開昭６２−２５１７４０号公報や特開平３−２０８５１４号公報に記載されているような非イオン界面活性剤、特開昭５９−１２１０４４号公報、特開平４−１３１４９号公報に記載されているような両性界面活性剤、ＥＰ９５０５１７公報に記載されているようなシロキサン系化合物、特開平１１−２８８０９３号公報に記載されているようなフッ素含有のモノマー共重合体を添加することができる。
非イオン界面活性剤の具体例としては、ソルビタントリステアレート、ソルビタンモノパルミテート、ソルビタントリオレート、ステアリン酸モノグリセリド、ポリオキシエチレンノニルフェニルエーテル等が挙げられる。両面活性剤の具体例としては、アルキルジ（アミノエチル）グリシン、アルキルポリアミノエチルグリシン塩酸塩、２−アルキル−Ｎ−カルボキシエチル−Ｎ−ヒドロキシエチルイミダゾリニウムベタインやＮ−テトラデシル−Ｎ，Ｎ−ベタイン型（例えば、商品名「アモーゲンＫ」：第一工業（株）製）等が挙げられる。
シロキサン系化合物としては、ジメチルシロキサンとポリアルキレンオキシドのブロック共重合体が好ましく、具体例として、（株）チッソ社製、ＤＢＥ−２２４，ＤＢＥ−６２１，ＤＢＥ−７１２，ＤＢＰ−７３２，ＤＢＰ−５３４、独Ｔｅｇｏ社製、Ｔｅｇｏ Ｇｌｉｄｅ１００等のポリアルキレンオキシド変性シリコーンを挙げることが出来る。
上記非イオン界面活性剤および両性界面活性剤の感光性組成物中に占める割合は、０．０５〜１５質量％が好ましく、より好ましくは０．１〜５質量％である。
【０１５８】
また、露光による加熱後直ちに可視像を得るための焼き出し剤や、画像着色剤としての染料や顔料を加えることができる。
焼き出し剤としては、露光による加熱によって酸を発生する化合物（光酸発生剤）と塩を形成し得る有機染料の組合せを代表として挙げることができる。具体的には、特開昭５０−３６２０９号、同５３−８１２８号の各公報に記載されているｏ−ナフトキノンジアジド−４−スルホン酸ハロゲニドと塩形成性有機染料の組合せや、特開昭５３−３６２２３号、同５４−７４７２８号、同６０−３６２６号、同６１−１４３７４８号、同６１−１５１６４４号および同６３−５８４４０号の各公報に記載されているトリハロメチル化合物と塩形成性有機染料の組合せを挙げることができる。かかるトリハロメチル化合物としては、オキサゾール系化合物とトリアジン系化合物とがあり、どちらも経時安定性に優れ、明瞭な焼き出し画像を与える。
【０１５９】
画像の着色剤としては、前述の塩形成性有機染料以外に他の染料を用いることができる。塩形成性有機染料を含めて、好適な染料として油溶性染料と塩基性染料を挙げることができる。具体的にはオイルイエロー＃１０１、オイルイエロー＃１０３、オイルピンク＃３１２、オイルグリーンＢＧ、オイルブルーＢＯＳ、オイルブルー＃６０３、オイルブラックＢＹ、オイルブラックＢＳ、オイルブラックＴ−５０５（以上オリエント化学工業（株）製）、ビクトリアピュアブルー、クリスタルバイオレット（ＣＩ４２５５５）、メチルバイオレット（ＣＩ４２５３５）、エチルバイオレット、ローダミンＢ（ＣＩ１４５１７０Ｂ）、マラカイトグリーン（ＣＩ４２０００）、メチレンブルー（ＣＩ５２０１５）などを挙げることができる。また、特開昭６２−２９３２４７号公報に記載されている染料は特に好ましい。これらの染料は、記録層全固形分に対し、０．０１〜１０質量％、好ましくは０．１〜３質量％の割合で記録層中に添加することができる。
【０１６０】
更に、記録層中には必要に応じ、塗膜の柔軟性等を付与するために可塑剤が加えられる。例えば、ブチルフタリル、ポリエチレングリコール、クエン酸トリブチル、フタル酸ジエチル、フタル酸ジブチル、フタル酸ジヘキシル、フタル酸ジオクチル、リン酸トリクレジル、リン酸トリブチル、リン酸トリオクチル、オレイン酸テトラヒドロフルフリル、アクリル酸またはメタクリル酸のオリゴマーおよびポリマー等が用いられる。
【０１６１】
［平版印刷版原版の形成］
本発明の記録層を、平版印刷版原版に適用する際は、上記記録層成分を溶媒に溶かして、適当な支持体上に塗布することにより製造することができる。
また、目的に応じて、後述する樹脂中間層、下塗り層、バックコート層なども同様にして形成することができる。
ここで使用する溶媒としては、エチレンジクロライド、シクロヘキサノン、メチルエチルケトン、メタノール、エタノール、プロパノール、エチレングリコールモノメチルエーテル、１−メトキシ−２−プロパノール、２−メトキシエチルアセテート、１−メトキシ−２−プロピルアセテート、ジメトキシエタン、乳酸メチル、乳酸エチル、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、テトラメチルウレア、Ｎ−メチルピロリドン、ジメチルスルホキシド、スルホラン、γ−ブチロラクトン、トルエン等をあげることができるがこれに限定されるものではない。これらの溶媒は単独あるいは混合して使用される。
溶媒中の上記成分（添加剤を含む全固形分）の濃度は、好ましくは１〜５０質量％である。
また塗布、乾燥後に得られる支持体上の塗布量（固形分）は、用途によって異なるが、平版印刷版原版についていえば一般的に０．５〜５．０ｇ／ｍ²が好ましい。塗布量が少なくなるにつれて、見かけの感度は大になるが、記録層の皮膜特性は低下する。
塗布する方法としては、種々の方法を用いることができるが、例えば、バーコーター塗布、回転塗布、スプレー塗布、カーテン塗布、ディップ塗布、エアーナイフ塗布、ブレード塗布、ロール塗布等を挙げることができる。
【０１６２】
本発明の記録層には、塗布性を良化するための界面活性剤、例えば特開昭６２−１７０９５０号公報に記載されているようなフッ素系界面活性剤を添加することができる。好ましい添加量は、記録層全固形分中０．０１〜１質量％、さらに好ましくは０．０５〜０．５質量％である。
【０１６３】
本発明に係る平版印刷版原版には、必要に応じて、支持体と記録層との間に樹脂中間層を設けることができる。
この樹脂中間層を設けることで、支持体と記録層との間の高分子からなる樹脂中間層が断熱層として機能し、赤外線レーザの露光により発生した熱が支持体に拡散せず、効率よく使用されることから、高感度化が図れるという利点を有する。また、本発明に係る記録層は、この樹脂中間層を設ける際にも、露光面或いはその近傍に位置するため、赤外線レーザに対する感度は良好に維持される。
なお、未露光部においては、アルカリ現像液に対して非浸透性である記録層自体が樹脂中間層の保護層として機能するために、現像安定性が良好になるとともにディスクリミネーションに優れた画像が形成され、且つ、経時的な安定性も確保されるものと考えられ、露光部においては、溶解抑制能が解除された記録層の成分が速やかに現像液に溶解、分散し、さらには、支持体に隣接して存在するこの樹脂中間層自体がアルカリ可溶性高分子からなるものであるため、現像液に対する溶解性が良好で、例えば、活性の低下した現像液などを用いた場合でも、残膜などが発生することなく速やかに溶解し、現像性の向上にも寄与し、この樹脂中間層は有用であると考えられる。
【０１６４】
本発明に係る平版印刷版原版は、支持体上に記録層を設けたものであるが、必要に応じてその間に下塗層を設けることができる。
下塗層成分としては種々の有機化合物が用いられ、例えば、カルボキシメチルセルロース、デキストリン、アラビアガム、２−アミノエチルホスホン酸などのアミノ基を有するホスホン酸類、置換基を有してもよいフェニルホスホン酸、ナフチルホスホン酸、アルキルホスホン酸、グリセロホスホン酸、メチレンジホスホン酸およびエチレンジホスホン酸などの有機ホスホン酸、置換基を有してもよいフェニルリン酸、ナフチルリン酸、アルキルリン酸およびグリセロリン酸などの有機リン酸、置換基を有してもよいフェニルホスフィン酸、ナフチルホスフィン酸、アルキルホスフィン酸およびグリセロホスフィン酸などの有機ホスフィン酸、グリシンやβ−アラニンなどのアミノ酸類、およびトリエタノールアミンの塩酸塩などのヒドロキシ基を有するアミンの塩酸塩等から選ばれるが、２種以上混合して用いてもよい。
【０１６５】
また、本発明における好適な下塗層成分として、特開２０００−２４１９６２号公報に記載の酸基を有する構成成分とオニウム基を有する構成成分とを有する高分子化合物を挙げることができる。具体的には、酸基を有するモノマーとオニウム基を有するモノマーの共重合体が挙げられる。酸基として好ましいのは酸解離指数（ｐKa）が７以下の酸基であり、より好ましくは−ＣＯＯＨ、−ＳＯ₃Ｈ、−ＯＳＯ₃ Ｈ、−ＰＯ₃ Ｈ₂ 、−ＯＰＯ₃ Ｈ₂、−ＣＯＮＨＳＯ₂ −、または−ＳＯ₂ ＮＨＳＯ₂ −であり、特に好ましくは−ＣＯＯＨである。酸基を有するモノマーの具体例としては、アクリル酸、メタクリル酸、クロトン酸、イソクロトン酸、イタコン酸、マレイン酸、無水マレイン酸、上記酸基を有するスチレンなどが挙げられる。オニウム基として好ましいのは、周期律表第Ｖ族あるいは第ＶＩ族の原子からなるオニウム基であり、より好ましくは窒素原子、リン原子あるいはイオウ原子からなるオニウム基であり、特に好ましくは窒素原子からなるオニウム基である。オニウム基を有するモノマーの具体例としては、側鎖に第４級アンモニウム基を有するメタクリレート、メタクリルアミド、第４級アンモニウム基などのオニウム基を含む置換基を有するスチレン等が挙げられる。
【０１６６】
この有機下塗層は次のような方法で設けることができる。即ち、水またはメタノール、エタノール、メチルエチルケトンなどの有機溶剤もしくはそれらの混合溶剤に上記の有機化合物を溶解させた溶液をアルミニウム板上に塗布、乾燥して設ける方法と、水またはメタノール、エタノール、メチルエチルケトンなどの有機溶剤もしくはそれらの混合溶剤に上記の有機化合物を溶解させた溶液に、アルミニウム板を浸漬して上記化合物を吸着させ、その後水などによって洗浄、乾燥して有機下塗層を設ける方法である。前者の方法では、上記有機化合物の濃度０．００５〜１０質量％の溶液を種々の方法で塗布できる。また後者の方法では、溶液の濃度は０．０１〜２０質量％、好ましくは０．０５〜５質量％であり、浸漬温度は２０〜９０℃、好ましくは２５〜５０℃であり、浸漬時間は０．１秒〜２０分、好ましくは２秒〜１分である。これに用いる溶液は、アンモニア、トリエチルアミン、水酸化カリウムなどの塩基性物質や、塩酸、リン酸などの酸性物質によりｐＨ１〜１２の範囲に調整することもできる。また、画像記録材料の調子再現性改良のために黄色染料を添加することもできる。
有機下塗層の被覆量は、２〜２００ｍｇ／ｍ²が適当であり、好ましくは５〜１００ｍｇ／ｍ²である。被覆量を２〜２００ｍｇ／ｍ²とすることで充分な耐刷性能が得られる。
【０１６７】
本発明の平版印刷版原版の支持体裏面には必要に応じてバックコートを設けることができる。かかるバックコートとしては、特開平５−４５８８５号公報記載の有機高分子化合物、および特開平６−３５１７４号公報記載の有機または無機金属化合物を加水分解および重縮合させて得られる金属酸化物などの被覆層が挙げられる。これらの被覆層のうち、Ｓｉ(ＯＣＨ₃)₄、Ｓｉ(ＯＣ₂Ｈ₅)₄、Ｓｉ(ＯＣ₃Ｈ₇)₄、Ｓｉ(ＯＣ₄Ｈ₉)₄などのケイ素のアルコキシ化合物が安価で入手しやすく、それから得られる金属酸化物の被覆層が耐現像液に優れており、特に好ましい。
【０１６８】
［製版および印刷］
本発明の平版印刷版原版は熱により画像形成される。具体的には、熱記録ヘッド等による直接画像様記録、赤外線レーザによる走査露光、キセノン放電灯などの高照度フラッシュ露光や赤外線ランプ露光などが用いられるが、波長７００〜１２００ｎｍの赤外線を放射する半導体レーザ、ＹＡＧレーザ等の固体高出力赤外線レーザによる露光が好適である。
【０１６９】
露光された本発明の平版印刷版原版は、現像処理およびフィニッシャーや保護ガムなどによる後処理を施されて印刷版となる。これらの処理には、公知の自動現像機などの処理機器を用いることができる。
本発明の平版印刷版原版の現像処理および後処理に用いられる処理剤としては、公知の処理剤の中から適宜選択して用いることができる。
【０１７０】
好適な現像液としては、ｐＨが９．０〜１４．０の範囲、好ましくは１２．０〜１３．５の範囲にある現像液である。現像液には、従来から知られているアルカリ水溶液が使用できる。上記のアルカリ水溶液のうち、特に好適な現像液として、塩基としてケイ酸アルカリを含有した、または塩基にケイ素化合物を混ぜてケイ酸アルカリとしたものを含有した、従来から良く知られている所謂「シリケート現像液」と呼ばれるｐＨ１２以上の水溶液、および、特開平８−３０５０３９号、特開平１１−１０９６３７号公報等に記載の、ケイ酸アルカリを含有せず、非還元糖（緩衝作用を有する有機化合物）と塩基とを含有した所謂「ノンシリケート現像液」が挙げられる。
【０１７１】
本発明の平版印刷版をバーニング処理する場合は、バーニング整面液を用い、バーニングプロセサなどを用いて行う従来から知られている方法で行うことが好ましい。
【０１７２】
このような処理によって得られた平版印刷版はオフセット印刷機等にかけられ、多数枚の印刷に用いられる。
【０１７３】
【実施例】
以下、実施例により本発明を詳細に説明するが、本発明はこれらに限定されるものではない。なお、本願実施例においては、本発明の樹脂組成物を記録層として用いた平版印刷版原版についての評価を行い、その評価を本発明の樹脂組成物の評価とする。
・平版印刷版原版の製造
第１表に示す組成の各アルミニウム板に、各表面処理を施し、各平版印刷版用支持体を得た。
【表１】

【０１７４】
（ａ）機械的粗面化処理
比重１．１２の研磨剤（ケイ砂）と水との懸濁液を研磨スラリー液としてアルミニウム板の表面に供給しながら、回転するローラ状ナイロンブラシにより機械的な粗面化を行った。研磨剤の平均粒径は８μｍ、最大粒径は５０μｍであった。ナイロンブラシの材質は６・１０ナイロン、毛長５０ｍｍ、毛の直径は０．３ｍｍであった。ナイロンブラシはφ３００ｍｍのステンレス製の筒に穴をあけて密になるように植毛した。回転ブラシは３本使用した。ブラシ下部の２本の支持ローラ（φ２００ｍｍ）の距離は３００ｍｍであった。ブラシローラはブラシを回転させる駆動モータの負荷が、ブラシローラをアルミニウム板に押さえつける前の負荷に対して７ｋＷプラスになるまで押さえつけた。ブラシの回転方向はアルミニウム板の移動方向と同じであった。ブラシの回転数は一本目が２５０ｒｐｍ、二本目および三本目が２００ｒｐｍであった。
【０１７５】
（ｂ）アルカリエッチング処理
上記で得られたアルミニウム板に温度７０℃のＮａＯＨ水溶液（濃度２６質量％、アルミニウムイオン濃度５質量％）をスプレーしてエッチング処理を行い、アルミニウム板を１０ｇ／ｍ²溶解した。その後、井水を用いてスプレーによる水洗を行った。
【０１７６】
（ｃ）デスマット処理
温度３０℃の硝酸濃度１質量％水溶液（アルミニウムイオンを０．５質量％含む）で、スプレーによるデスマット処理を行い、その後、スプレーで水洗した。前記デスマットに用いた硝酸水溶液は、硝酸水溶液中で交流を用いて電気化学的な粗面化を行う工程の廃液を用いた。
【０１７７】
（ｄ）電気化学的粗面化処理
６０Ｈｚの交流電圧を用いて連続的に電気化学的な粗面化処理を行った。このときの電解液は、硝酸１０．５ｇ／リットル水溶液（アルミニウムイオンを５ｇ／リットル）、温度５０℃であった。交流電源波形は電流値がゼロからピークに達するまでの時間ＴＰが０．８ｍｓｅｃ、ＤＵＴＹ比１：１、台形の矩形波交流を用いて、カーボン電極を対極として電気化学的な粗面化処理を行った。補助陽極にはフェライトを用いた。使用した電解槽はラジアルセルタイプのものを使用した。
電流密度は電流のピーク値で３０Ａ／ｄｍ²、電気量はアルミニウム板が陽極時の電気量の総和で１７５Ｃ／ｄｍ²であった。補助陽極には電源から流れる電流の５％を分流させた。
その後、井水を用いてスプレーによる水洗を行った。
【０１７８】
（ｅ）アルカリエッチング処理
アルミニウム板をカセイソーダ濃度２６質量％、アルミニウムイオン濃度５質量％でスプレーによるエッチング処理を３２℃で行い、アルミニウム板を０．５ｇ／ｍ²溶解し、前段の交流を用いて電気化学的な粗面化を行ったときに生成した水酸化アルミニウムを主体とするスマット成分を除去し、また、生成したピットのエッジ部分を溶解してエッジ部分を滑らかにした。その後、井水を用いてスプレーによる水洗を行った。
【０１７９】
（ｆ）デスマット処理
温度３０℃の硫酸濃度２５質量％水溶液で、スプレーによるデスマット処理を行い、その後、井水を用いてスプレーで水洗した。前記デスマットに用いた硝酸水溶液は、硝酸水溶液中で交流を用いて電気化学的な粗面化を行う工程の廃液を用いた。
【０１８０】
（ｇ）電気化学的粗面化処理
６０Ｈｚの交流電圧を用いて連続的に電気化学的な粗面化処理を行った。このときの電解液は、塩酸５．０ｇ／リットル水溶液（アルミニウムイオンを５ｇ／リットル含む）、温度３５℃であった。交流電源波形は矩形波であり、カーボン電極を対極として電気化学的な粗面化処理を行った。補助アノードにはフェライトを用いた。電解槽はラジアルセルタイプのものを使用した。
電流密度は電流のピーク値で２５Ａ／ｄｍ²、電気量はアルミニウム板が陽極時の電気量の総和で５０Ｃ／ｄｍ²であった。その後、井水を用いてスプレーによる水洗を行った。
【０１８１】
（ｈ）アルカリエッチング処理
アルミニウム板をＮａＯＨ濃度５質量％、アルミニウムイオン濃度０．５質量％でスプレーによるエッチング処理を３２℃で行い、アルミニウム板を０．１０ｇ／ｍ²溶解し、前段の交流を用いて電気化学的な粗面化処理を行ったときに生成した水酸化アルミニウムを主体とするスマット成分を除去し、また、生成したピットのエッジ部分を溶解してエッジ部分を滑らかにした。その後、井水を用いてスプレーによる水洗を行った。
【０１８２】
（ｉ）デスマット処理
温度６０℃の硫酸濃度２５質量％水溶液で、スプレーによるデスマット処理を行い、その後、井水を用いてスプレーによる水洗を行った。
【０１８３】
（ｊ）陽極酸化処理
電解液としては、硫酸を用いた。電解液は、いずれも硫酸濃度１５０ｇ／リットル（アルミニウムイオンを０．５質量％含む。）、温度は４３℃であった。その後、井水を用いてスプレーによる水洗を行った。
電流密度はともに約３０Ａ／ｄｍ²であった。最終的な酸化皮膜量は２．５ｇ／ｍ²であった。
【０１８４】
（ｋ）シリケート処理
温度は３５℃の３号珪酸ソーダ水溶液で、ディップによるシリケート処理を行い、その後、井水を用いてスプレーによる水洗を行った。
【０１８５】
＜支持体Ｘ＞
上記（ａ）〜（ｋ）の各工程を順に行い支持体を作製した。（ｅ）工程におけるエッチング量は０．５ｇ／ｍ²となるように設定した。
＜支持体Ｙ＞
上記工程のうち（ｇ）（ｈ）（ｉ）の工程を省略した以外は各工程を順に行い支持体を作製した。
＜支持体Ｚ＞
上記工程のうち（ａ）及び（ｇ）（ｈ）（ｉ）の工程を省略した以外は各工程を順に行い支持体を作製した。なお、（ｅ）工程におけるエッチング量は３．５ｇ／ｍ²に変更した。
【０１８６】
（下塗り処理）
上記のようにして得られたアルカリ金属ケイ酸塩処理後のアルミニウム支持体上に、下記組成の下塗り液を塗布し、８０℃で１５秒間乾燥した。乾燥後の被覆量は１５ｍｇ／ｍ²であった。
【０１８７】
＜下塗り液組成＞
・下記高分子化合物 ０．３ｇ
・メタノール １００ｇ
・水 １．０ｇ
【０１８８】
【化２７】

【０１８９】
〔実施例１〜７、比較例１〜９〕
得られた支持体Ｘ〜Ｚに、前記下塗り液を塗布した後、下記組成の下層用塗布液えを、ウエット塗布量が１８．７５ｍｌ／ｍ²のワイヤーバーで塗布後、１３０℃の乾燥オーブンで５０秒間乾燥した。乾燥後の下層被覆量は０．８５ｇ／ｍ²であった。
得られた下層付き支持体に、下記組成の画像記録層（上層）用塗布液２を、ウエット塗布量が１８．７５ｍｌ／ｍ²のワイヤーバーで塗布を行い総塗布量を１．１０ｇ／ｍ²とした。塗布後、乾燥オーブンで１４０℃で６０秒間の乾燥を行いポジ型平版印刷版原版を作製した。
【０１９０】

【０１９１】

【０１９２】
【化２８】

【０１９３】
【化２９】

【０１９４】
【化３０】

【０１９５】
下層にチオール化合物を添加しない感光層を用いて得たものを平版印刷用原版ａとし、下層にＣ−１を添加した感光層を用いて得たものを平版印刷用原版ｂ、下層にＣ−２を添加した感光層を用いて得たものを平版印刷用原版ｃ、下層にＣ−３を添加した感光層を用いて得たものを平版印刷用原版ｄとした。
【０１９６】
〔感度の評価〕
得られた平版印刷用原版をＣｒｅｏ社製Ｔｒｅｎｄｓｅｔｔｅｒ３２４４にて書き込み回転数を１５０ｒｐｍに固定し、レーザー出力を３〜８Ｗで０．２５Ｗ刻みで露光エネルギーを変えて描き込みを行った。その後、ＬＰ−９４０Ｈ（富士写真フイルム（株）製自動現像機）の現像処理浴に、サーマルポジ用現像液（富士写真フィルム(株)製ＤＴ−２）１部に対して水８部で希釈した液を２０リットル仕込み、３０℃に保温し、第二浴目には水道水を８リットル、第三浴目にはフィニッシングガム（富士写真フィルム(株)製ＦＧ−１）１部を水１部で希釈した液を８リットル仕込んだ。現像スピードは現像時間１２秒になるように設定した。現像液で非画像部が現像できる露光量（ドラム回転速度１５０ｒｐｍのときのビーム強度）を測定し、感度とした。数値が小さいほど高感度であると評価する。
【０１９７】
得られた平版印刷版について印刷試験を行い、以下のようにして耐刷性及び汚れにくさを評価した。
〔耐刷性の評価〕
印刷機として、三菱ダイヤマチック印刷機を用い、インキとして、ジオスＧ（Ｓ）墨色を用い、湿し水として、富士写真フイルム（株）製のＥＵ−３（１：１００）に、イソプロパノールを全体の７質量％となるように添加した液を用いて、印刷を行った。
ベタ画像部が薄くかすれ始めたことが目視で認められるまでの印刷枚数により評価した。なお、耐刷性は、実施例１の耐刷性を１００とした相対値で示した。
【０１９８】
〔汚れにくさ〕
印刷機として、三菱ダイヤマチック印刷機を用い、インキとして、ジオスＧ（Ｓ）紅色を用い、湿し水として、富士写真フイルム（株）製のＥＵ−３（１：１００）に、イソプロパノールを全体の７質量％となるように添加した液を用いて、印刷を行った。印刷時に、版に相対するブランケット上に発生した非画像部の汚れを、セロハンテープに転写させて採取し、インキの付着した程度によって、４段階評価した。インキ付着のないものから多いものの順に、◎、○、△、×とした。
これらの結果を表２に示す。
【０１９９】
【表２】

【０２００】
表２から、銅含有量が０．００５質量％以下であり、表面のピットの平均径が１．２μｍ以下、ピットの平均密度が１×１０⁶〜１２５×１０⁶個／ｍｍ²であるアルミニウム支持体上に、チオール化合物が添加されている記録層をもつ例のみが、耐刷と汚れのバランスを維持しつつ高感度化を達成しえることがわかる。記録層にチオール化合物が添加されていない場合、感度が低い。また、前記支持体よりピット径が大きく、ピット平均密度が低いものは、印刷性能（耐刷、汚れ）が低いことが明らかである。
【０２０１】
〔実施例８、比較例１０〜１１〕
実施例１〜７、比較例１〜９と同様にして得られた支持体上に、下記の画像記録層用塗布液１を塗布した後、１５０℃の乾燥オーブンで１分間乾燥して乾燥膜厚が１．８ｇ／ｍ²のポジ型画像記録層を有する平版印刷版原版を作製した。
【０２０２】

【０２０３】
【化３１】

【０２０４】
チオール化合物を添加しない感光層を用いて得たものを平版印刷用原版ｅとし、チオール化合物Ｃ−１を添加した感光層を用いて得たものを平版印刷用原版ｆとした。
【０２０５】
〔感度の評価〕
得られた平版印刷用原板をＣｒｅｏ社製Ｔｒｅｎｄｓｅｔｔｅｒ３２４４にて書き込み回転数を１５０ｒｐｍに固定し、レーザー出力を３〜８Ｗで０．２５Ｗ刻みで露光エネルギーを変えて描き込みを行った。その後、ＦＬＨ−８５Ｎ（富士写真フイルム（株）製自動現像機）の現像処理浴に、サーマルポジ用現像液（富士写真フィルム(株)製ＬＨ−ＤＳ）を仕込み、２８℃に保温し、第二浴目には水道水を、第三浴目にはフィニッシングガム（富士写真フィルム(株)製ＦＮ−６）１部を水１部で希釈した液を８リットル仕込んだ。現像スピードは現像時間２６秒になるように設定した。現像液で非画像部が現像できる露光量（ドラム回転速度１５０ｒｐｍのときのビーム強度）を測定し、感度とした。数値が小さいほど高感度であると評価する。
【０２０６】
〔耐刷性および汚れの評価〕
実施例１〜７及び比較例１〜９と同様にして耐刷性および汚れを評価した。
これらの結果を表３に示す。
【０２０７】
【表３】

【０２０８】
表３から、本発明に係わる支持体とチオール化合物を含有する記録層とを有する実施例８が、耐刷と汚れのバランスを維持しつつ高感度化を達成しえることがわかる。
【０２０９】
〔実施例９〜１０〕
実施例５及び実施例８で用いた平版印刷用原版をＣｒｅｏ社製Ｔｒｅｎｄｓｅｔｔｅｒ３２４４にてドラム回転数を１５０ｒｐｍで露光した。その後、下記アルカリ現像液Ａ組成を仕込んだ９００Ｈ（富士写真フイルム（株）製ＰＳプロセッサー）を用い、液温を２８℃に保温し、実施例５のもの（実施例９）を１０秒、実施例８のもの（実施例１０）を２０秒で現像した。これらについて、実施例１〜７、比較例１〜９と同様にして感度、耐刷性および汚れを評価した。結果を表４に示す。
【０２１０】

【０２１１】
【表４】

【０２１２】
表４に示された結果から、本発明の平版印刷版原版は、非シリケート系のみならず、Ａ組成のようなシリケート系現像液を使用した場合においても、感度および印刷性能に優れていることが確認された。
【０２１３】
【発明の効果】
本発明によれば、良好な感度、耐刷性および汚れにくさに優れた平版印刷版原版を提供できる。また、アルカリ金属ケイ酸塩を含有しない現像液でも良好に処理できる平版印刷版原版を提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lithographic printing plate precursor, and more particularly, to a so-called infrared laser lithographic printing plate precursor for direct plate making, in which a digital image signal generated and output by a computer can be recorded with an infrared laser beam to directly perform plate making.
[0002]
[Prior art]
Conventionally, as a system for making a plate directly from digital data of a computer, (1) an electrophotographic method, (2) a photopolymerization method such as Ar ion laser exposure, and (3) a silver salt emulsion on a photosensitive resin layer Those in which layers are laminated, and those using (4) silver salt diffusion transfer are known.
However, those using the electrophotographic method (1) require complicated processes such as charging, exposure, and development, and the apparatus becomes complicated and large. The methods {circle around (2)}, {circle around (3)} and {circle around (4)} are visible light sensitive and therefore difficult to handle in a bright room. Furthermore, the methods (3) and (4) have the disadvantage that the processing becomes complicated and the cost is increased because silver salt is used.
On the other hand, the development of lasers in recent years has been remarkable, and in particular, solid-state lasers / semiconductor lasers having a light emitting region from near infrared to infrared have become readily available for high-power and small-sized devices. A lithographic printing plate precursor that directly makes a plate from digital data such as a computer using an infrared laser as a light source can be handled in a bright room and is very preferable for plate making operations.
[0003]
As a lithographic printing plate precursor for direct plate making using such an infrared laser, a negative lithographic plate containing an infrared absorber, a compound that generates an acid by heat (acid generator), a crosslinking agent that undergoes a crosslinking reaction with an acid, and a binder polymer The printing plate precursor is known. However, since this negative lithographic printing plate precursor requires heating after exposure in order to cause a cross-linking reaction, the number of steps is complicated and there is a problem of high energy consumption for heating.
[0004]
Therefore, as an infrared laser lithographic printing plate precursor that does not require heating after exposure, (A) an alkaline aqueous solution-soluble resin having a phenolic hydroxyl group such as a cresol novolak resin and (B) a recording layer containing an infrared absorber A type lithographic printing plate precursor has been proposed. In this positive type lithographic printing original plate, the association state of the cresol novolak resin is changed by the action of heat generated by the infrared absorber in the exposed area, resulting in a difference in solubility (dissolution rate difference) from the unexposed area. Is used to develop and form an image. However, since the difference in dissolution rate is small, the actual plate-making operation is easily affected by slight fluctuations in alkali activity and lacks stability. That is, there is a problem that the development latitude is narrow.
[0005]
As a countermeasure for the above-mentioned problem of the positive type lithographic printing original plate, a technique for enlarging the development latitude with an alkali dissolution inhibitor (dissolution inhibitor) is being actively developed. For example, Patent Document 1 (WO 98/42507 pamphlet) proposes the use of a compound having a hydrogen bond group as a dissolution inhibitor for enlarging development latitude. However, this method of suppressing the solubility by hydrogen bonds is liable to cause a decrease in sensitivity and deterioration of the suitability for baking because hydrogen bonds dissociated by exposure cause a reverse reaction over time after exposure. Furthermore, since the number of hydrogen-bonding sites fluctuates depending on the aging conditions even before exposure, there was a fatal defect that the alkali activity of the developer that can be developed changes.
[0006]
On the other hand, photosensitive lithographic printing plate precursors using an aluminum plate as a support are widely used for offset printing. This lithographic printing plate precursor is generally obtained by providing a recording layer by applying a roughening treatment to the surface of an aluminum plate, further subjecting it to an anodic oxidation treatment, applying a photosensitive solution and drying. When the roughening treatment including the electrolytic roughening treatment is performed, minute irregularities (pits) are generated on the surface of the support. In order to improve the adhesion between the recording layer and the support, a method for improving the shape and uniformity of the electrolytic roughening pits has been proposed.
However, the pits on the surface of the support have a substantially bowl-like shape, the diameter is uniform and large, and when the depth is deep, the recording layer enters the bottom part of the pit and the recording layer While the adhesiveness between the pit and the support is sufficient, the recording layer is relatively thin at the edge of the pit and the edge of the pit is sharp. There is a problem that a strong stress is easily applied to the recording layer on the upper portion of the recording layer, and the recording layer in that portion is liable to break or peel off.
As a countermeasure against this problem, there is known a method of chemically dissolving the edge of the edge portion. However, when the edge portion is dissolved, the present inventors have confirmed that the number of printing durability (the recording layer of the image portion of the lithographic printing plate is It has been found that the number of prints (before printing becomes impossible) tends to decrease due to peeling or abrasion.
[0007]
In addition, for the purpose of improving the stain resistance (resistance to stains) of a lithographic printing plate, by adding an alkali metal silicate to the developer, silicate is added only to the non-image area from which the recording layer has been removed. It is generally performed to adhere and further improve the hydrophilicity of the non-image area. However, when developing using a developer containing alkali metal silicate, SiO ₂ In the neutralization process when processing the development waste liquid. ₂ There was a problem such as the formation of a gel due to. As a countermeasure for this problem, the surface of the lithographic printing plate support, which is a non-image part of the lithographic printing plate, is treated with an alkali metal silicate solution in advance, and a recording layer is provided. There has been proposed a technique for developing using a developer that does not contain (see Patent Document 2 (Japanese Patent Application Laid-Open No. 11-109637)).
[0008]
However, this technique has a problem that the adhesion between the recording layer and the support is weakened. Therefore, by controlling the content of specific elements in the aluminum plate used for the lithographic printing plate support, the pits on the electrolytically roughened support surface are made uniform so that the recording layer and the support adhere to each other. It has been found that a lithographic printing plate precursor having improved printing properties, excellent printing durability when used as a lithographic printing plate, and excellent in resistance to dirt can be obtained (Patent Document 3 (Japanese Patent Publication No. 1-447545). ), And Patent Document 4 (Japanese Patent Laid-Open No. 8-337835).
[0009]
[Patent Document 1]
International Publication No. 98/42507 Pamphlet
[Patent Document 2]
JP-A-11-109637
[Patent Document 3]
Japanese Patent Publication No. 1-447545
[Patent Document 4]
JP-A-8-337835
[0010]
However, even when the above-described support technology is used, the above-mentioned infrared laser positive recording layer has a small development speed difference between the exposed portion and the unexposed portion (that is, small discrepancy) and a narrow development latitude. In the case of a lithographic printing plate precursor, depending on the development conditions, the deep part of the pit of the support tends to be poorly developed, and if the lithographic printing plate precursor is left for a long time under high temperature and humidity conditions, In particular, there was a problem of reducing dirtiness.
[0011]
[Problems to be solved by the invention]
The object of the present invention is to solve these problems. That is, an object of the present invention is to provide a lithographic printing plate precursor capable of recording an image with an infrared laser based on a digital signal and having excellent sensitivity, printing durability and resistance to stains. Another object of the present invention is to provide a lithographic printing plate precursor that can be satisfactorily processed with a developer containing no alkali metal silicate.
[0012]
[Means for Solving the Problems]
As a result of intensive studies, the present inventor has found that the above object can be achieved by a lithographic printing plate precursor having a specific recording layer on a specific support. That is, the present invention is as follows.
The copper content of the raw material aluminum alloy is 0.005% by mass or less, surface roughening treatment including electrochemical surface roughening treatment is performed, the average diameter of the surface pits is 1.2 μm or less, Average density is 1 × 10 ⁶ ~ 125 × 10 ⁶ Piece / mm ² A lithographic printing plate precursor comprising a recording layer containing (A) an alkali-soluble resin, (B) an infrared absorber, and (C) a thiol compound on an aluminum support.
[0013]
The present invention achieves the above object by electrolytically roughening an aluminum plate having a controlled copper content, and further using a support having a controlled average diameter and average density of surface pits and a recording layer containing a thiol compound. did it. In particular, positive lithographic printing with excellent printing durability and stain resistance can be obtained by controlling the average diameter and average density of the support surface pits, and it has excellent discrimination by including a thiol compound in the recording layer. The original edition has been achieved.
The improvement of the discrimination by the thiol compound is considered to be due to the improvement of the solubility resistance in the developer in the image portion and the improvement in the solubility in the developer in the non-image portion. That is, the improvement in dissolution resistance in the image area is that the thiol compound has higher acidity than the phenol-soluble hydroxyl group-containing compound that is an alkali-soluble resin, but has low polarization between SH bonds and low hydrophilicity. Therefore, it is considered that it can be obtained by suppressing the penetration of the alkaline developer into the formed coating film. On the other hand, the improvement in the solubility in the developer in the non-image area is that the interaction such as the association of the alkali-soluble resin is released by exposure, the developer penetrates and the thiol compound is eluted, and the thiol compound is dissolved due to its high acidity. It is thought that it is dissociated and functions as a dissolution accelerator.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, each component constituting the lithographic printing plate precursor according to the invention will be described in order.
[0015]
[Support]
<Aluminum plate (rolled aluminum)>
An aluminum alloy having a copper (Cu) content of 0.005% by mass or less is used for the lithographic printing plate support of the present invention. Other alloy components that may be included include Fe, Si, and Ti. Further, it preferably contains at least one of Ni or V. Furthermore, Mg can also be contained.
[0016]
Cu is a very important element in controlling the electrolytic surface roughening treatment. By controlling the Cu content with a small value, it is possible to generate extremely uniform and fine pits, preferably by controlling the Cu content in association with the Si content as described later. Cu content in this invention is 0.005 mass% or less. More preferably, it is 0.003 mass% or less.
[0017]
Fe is usually contained in an aluminum alloy (Al ingot) used as a raw material in an amount of about 0.04 to 0.2% by mass. Fe has an effect of increasing the mechanical strength of the aluminum alloy, and greatly affects the strength of the support. If the Fe content is too small, the mechanical strength is too low, and it becomes easy to cause plate breakage when the lithographic printing plate is attached to the plate cylinder of a printing press. Further, when printing a large number of copies at high speed, the plate is likely to be cut out similarly. On the other hand, when the Fe content is too high, the strength becomes higher than necessary, and when the lithographic printing plate is attached to the plate cylinder of a printing press, the fitness is inferior, and the plate is easily cut during printing. In the present invention, the Fe content is preferably 0.1% by mass or more and 0.5% by mass or less. In order to prevent the planographic printing plate from being cut during printing, the Fe content is more preferably 0.2% by mass or more.
[0018]
Si is contained as an inevitable impurity in the Al ingot, which is a raw material, and is often intentionally added in a small amount in order to prevent variations due to differences in raw materials.
In this invention, Si content is 0.02 mass% or more, and 0.10 mass% or less is preferable. More preferably, it is 0.04 mass% or more and 0.08 mass% or less from the surface of stability.
[0019]
When the Si content (mass%) in the aluminum alloy is expressed as [Si] and the Cu content (mass%) as [Cu], the following formula
[Si] / 10 + [Cu] ≦ 0.01
It is preferable to satisfy. When the above formula is satisfied, more uniform and finer pits can be generated.
[0020]
Ti has been contained in order to make the crystal structure at the time of casting finer. If the Ti content is too large, the resistance of the surface oxide film becomes excessive in the electrolytic surface-roughening treatment, so that uniform pits may not be formed. In the present invention, the Ti content is preferably 0.05% by mass or less, and more preferably 0.03% by mass or less.
Moreover, it is preferable that Ti content is 0.005 mass% or more. Ti is an optional component, and a small amount of Ti contained as an inevitable impurity in the raw Al base metal may be utilized for crystal refinement, but in order to enhance the crystal refinement effect, an Al-Ti alloy or It is preferable to add it as an Al-B-Ti alloy. When added as an Al—B—Ti alloy, a trace amount of B is contained in the aluminum alloy, but the characteristics of the present invention are not impaired.
[0021]
In the present invention, the aluminum alloy contains at least one of Ni and V in a range of Ni: 0.002 to 0.005 mass% and V: 0.01 to 0.05 mass%. preferable.
Many proposals have been made to add 0.005% by mass or more of Ni as an element for improving the efficiency of electrolytic surface roughening. Further, it is known that a maximum of 0.002% by mass is contained in the Al ingot. V is known to be contained in Al ingots at a maximum of about 0.01% by mass.
According to the knowledge of the present inventor, when the Si and Cu contents of the aluminum alloy are controlled within the ranges described above, Ni is contained in an amount of 0.002 to 0.005 mass%, or V is 0.01 By containing ˜0.05% by mass, or by containing both Ni and V in the above range, improvement in the uniformity of the electrolytic surface-roughening treatment and refinement of pits can be promoted.
In addition, when Ni and / or V are contained in the above range in the aluminum alloy, it is preferable to add as much as necessary by taking advantage of the content in the Al metal to be used.
[0022]
Moreover, the aluminum alloy of the present invention can contain Mg. Mg is an important element for controlling the electrolytic surface roughening treatment, and also has an effect of improving the strength of the lithographic printing plate. In particular, the Mg content is preferably 0.1% by mass or more in order to prevent the lithographic printing plate from being broken during printing. On the other hand, it is preferable that it is 1.0 mass% or less from the point of raw material cost.
[0023]
The balance of the aluminum plate is made of Al and inevitable impurities. Most of the inevitable impurities are contained in the Al ingot. If the inevitable impurities are contained in, for example, a metal having an Al purity of 99.7%, the effects of the present invention are not impaired. For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.
[0024]
In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, unnecessary gases such as hydrogen mixed in the molten metal and solid impurities are removed. Examples of the cleaning treatment for removing unnecessary gas include flux treatment; degassing treatment using argon gas, chlorine gas, or the like. In addition, as a cleaning process for removing solid impurities, for example, a so-called rigid media filter such as a ceramic tube filter or a ceramic foam filter, a filter using alumina flakes or alumina balls as a filter medium, a glass cloth filter, or the like is used. A filtering process is mentioned. Moreover, the cleaning process which combined the degassing process and the filtering process can also be performed.
[0025]
These cleaning treatments are preferably carried out in order to prevent defects due to foreign substances such as non-metallic inclusions and oxides in the molten metal and defects due to gas dissolved in the molten metal. As the molten metal filtering process, for example, JP-A-6-57342, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, The methods described in Kaihei 5-311261 and JP-A-6-136466 can be used. As the degassing treatment of the molten metal, for example, the methods described in JP-A-5-51659, JP-A-5-51660, JP-A-5-49148 and JP-A-7-40017 are used. Can be used.
[0026]
Next, the molten aluminum alloy is cast by either a casting method using a fixed mold typified by a DC casting method or a casting method using a driving mold typified by a continuous casting method.
When the DC casting method is used, it is preferable to solidify at a cooling rate in the range of 1 to 300 ° C./second. It is preferable to set the cooling rate to 1 ° C./second or more because formation of coarse intermetallic compounds can be suppressed.
As the continuous casting method, a method using a cooling roll typified by the Hunter method and the 3C method, and a method using a cooling belt or a cooling block typified by the Husley method and the Al Swiss Caster II type are industrially performed. Yes. When the continuous casting method is used, it is solidified at a cooling rate in the range of 100 to 1000 ° C./second. In general, the continuous casting method has a feature that the solid solution of the alloy component with respect to the aluminum matrix can be increased because the cooling rate is higher than that of the DC casting method. With regard to the continuous casting method, for example, JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, JP-A-6-122949, JP-A-6-122949. The methods described in JP-A-6-210406 and JP-A-6-262308 can be used.
[0027]
In the case of the DC casting method, an ingot having a plate thickness of 300 to 800 mm is manufactured, and 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut by face milling according to a conventional method. Thereafter, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. By performing the treatment for 1 hour or longer, the effect of the soaking treatment is often sufficiently obtained. If it is not necessary to stabilize the intermetallic compound, the soaking treatment can be omitted.
[0028]
Thereafter, hot rolling and cold rolling are performed to obtain a rolled plate of an aluminum alloy plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after cold rolling, or in the middle thereof. The condition is that heating is performed at 280 to 600 ° C. for 2 to 20 hours using a batch type annealing furnace, preferably 350 to 500 ° C. for 2 to 10 hours, or using a continuous annealing furnace at 400 to 600 ° C. for 6 minutes or less. It is preferably heated at 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 ° C./second or more using a continuous annealing furnace. If the crystal structure is fine at the end of hot rolling, intermediate annealing may be omitted. For cold rolling, for example, a method described in JP-A-6-210308 can be used.
[0029]
The aluminum alloy plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm may be further improved in flatness by a correction device such as a roller leveler or a tension leveler.
The improvement (correction) of the flatness may be performed after the plate is cut into a sheet shape. However, in order to improve the productivity, it is preferably performed in a continuous coil state. When a tension leveler is used, it is preferable that the difference in elongation in the width direction before and after correction is within 0.06%. The difference in the elongation in the width direction before and after the correction can be obtained by, for example, the following method. First, before correction, two parallel lines are drawn perpendicularly to the sheet rolling direction, and the interval L between the parallel lines is accurately measured. Draw a line to divide the aluminum plate in the width direction, for example, 20 mm width to make a thin strip plate, measure the actual length of the portion corresponding to L of each strip plate after correction, Let this length be l. It is possible to measure the elongation ((l−L) / L × 100) (%) of each plate and determine the difference in the elongation in the width direction before and after correction from the plate with the largest elongation and the plate with the smallest elongation. it can.
[0030]
By such correction using a tension leveler or the like, the aluminum plate is cut and placed on a surface plate as a rectangular cut sheet having a length in the plate rolling direction of 1.5 m, and 0 from each of the sides perpendicular to the plate rolling direction. Place a weight covering the entire width of the cut sheet at a position 25 m inside, and hold down the curl, and for the inner length of 1 m, the maximum height of the two raised parts (distortion) parallel to the plate rolling direction It is possible to obtain an aluminum plate having a height of 2.0 mm or less, a number of raised portions (distortions) of 5 or less per side, and a total height of the raised portions (distortions) of 4.0 mm or less. In addition, when the corner of the cut sheet is lifted, this is also included in the number of lifted portions (distortions). Also, inside the aluminum plate, the maximum height of the raised portion (strain) is 2.0 mm or less, the number of the raised portions (strain) is 5 or less, and the total height of the raised portions (strain) is 4.0 mm. It is preferable that:
[0031]
The aluminum plate preferably has the following cross-sectional shape.
Usually, an aluminum plate is stored for a predetermined period while being wound as a coil. In the cross section of the plate, if the end of the plate, that is, the thickness of the ear portion is too thick, the thick portion will be plastically deformed while being wound in a coil shape for several thousand meters, which is called ear distortion. Distortion occurs. Similarly, if the inner thickness of the plate is too thick, plastic deformation occurs and an inner strain called abdominal strain occurs.
[0032]
Since the occurrence of abdominal distortion tends to be less likely to occur than ear distortion, in the present invention, priority is given to preventing the occurrence of ear distortion, and it is preferable to finish the thickness of the inner side of the plate slightly thicker than the end of the plate. . Specifically, in order to make the plate thickness of the ear portion relative to the average plate thickness of the plate below a certain value, it is preferable to set the a value defined as follows to 1.0 or less. Moreover, in order not to make the plate | board thickness inside a plate | board too thick with respect to average plate | board thickness, it is preferable to make pc value defined as follows 2.0% or less. In the cold rolling process described above, the a value and the pc value can be adjusted to desired values by adjusting the deflection shape of the cold rolling roll.
a = h / c
pc = c / tc × 100 (%)
h: Difference between ear thickness and minimum thickness
c: Difference between the maximum thickness at the center and the minimum thickness
tc: Maximum thickness at the center
These values can be understood more easily by referring to FIG. 2 of JP-A-11-254847.
[0033]
Moreover, in this invention, it is preferable that the curvature per 4 m length of an aluminum plate is 0.3 mm or less. When the bend of the aluminum plate is large, when it is wound as a coil, the winding shift gradually increases as it is wound, and the end of the plate due to the winding shift or distortion occurs. The target value of the bend can be achieved by controlling the parallelism of the cold rolling roll and the feeding accuracy of the aluminum plate in the cold rolling mill.
[0034]
In the present invention, the height of burrs at the end of the plate is preferably 10 μm or less. For the same reason as described in the description of the cross-sectional shape, if the burr at the end is large, plastic deformation at the end tends to occur while being wound and stored as a coil. In addition, in the surface treatment for obtaining a lithographic printing plate support and the recording layer coating process for preparing a lithographic printing plate precursor, burrs are likely to damage the lithographic printing plate precursor manufacturing equipment such as pass rolls and coating devices. Is not preferable. Therefore, as described above, the height of the burr is preferably 10 μm or less. The burr height can be reduced to 10 μm or less by controlling the clearance of the blade in the slitter process of cutting off the coil ears.
[0035]
In addition, a slitter line is usually used for processing to a predetermined plate width. At the end face of the plate cut by the slitter, when the slitter blade cuts, one or both of a shear plane and a fracture surface are generated.
[0036]
Regarding the accuracy of the plate thickness, the difference in plate thickness over the entire length of the coil is preferably within 20 μm, and more preferably within 12 μm. The plate thickness difference in the width direction is preferably 6 μm or less, and more preferably 3 μm or less. The plate width accuracy is preferably within 2.0 mm, more preferably within 1.0 mm.
[0037]
The surface roughness of the aluminum plate is easily affected by the surface roughness of the rolling roll, but finally the arithmetic average roughness R _a Is preferably finished to be about 0.1 to 1.0 μm. R _a Is about 1.0 μm or less, in the obtained lithographic printing plate precursor, the original roughness of the aluminum plate, that is, the rough rolling streaks transferred by the rolling roll cannot be seen from above the recording layer. preferable. R _a Is about 0.1 μm or more, it is not necessary to finish the surface of the rolling roll with excessively low roughness, which is industrially preferable.
[0038]
Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary. Oil amount is 100mg / m to prevent slip failure in the production line ² Preferably, it is 50 mg / m ² More preferably, it is 10 mg / m ² More preferably, the amount of oil is 3 mg / m in order to prevent scratches during coil transportation. ² The above is preferable.
[0039]
In the case of continuous casting, for example, according to a method using a cooling belt such as the Hunter method, a cast plate having a thickness of 1 to 10 mm can be directly continuously cast and rolled, and the hot rolling step can be omitted. There are advantages. Further, according to a method using a cooling roll such as the Hasley method, a cast plate having a thickness of 10 to 50 mm can be cast, and generally, it is continuously rolled using a hot rolling roll immediately after casting. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.
As described in the case of DC casting, the continuous cast and rolled plate obtained by these methods is subjected to processes such as cold rolling, intermediate annealing, flatness improvement, slitting, etc., to a predetermined thickness, for example, plate thickness. Finished to 0.1 to 0.5 mm. Regarding the conditions of intermediate annealing and cold rolling in the case of using the continuous casting method, for example, JP-A-6-220593, JP-A-6-210308, JP-A-7-54111 and JP-A-8-92709. Can be used.
[0040]
<Roughening treatment>
The aluminum plate is subjected to a roughening treatment including an electrochemical roughening treatment. In the present invention, as described above, since the aluminum alloy sheet contains a specific amount of a specific element, uniform and extremely fine pits can be generated by electrochemical surface roughening treatment. As a result, adhesion between the recording layer and the support is further improved, printing durability is improved, and resistance to dirt is also improved. Even when a laser direct-drawing type recording layer is provided using the lithographic printing plate support of the present invention to form a lithographic printing plate precursor for laser printing plate, the adhesion between the recording layer and the support is improved. be able to. Moreover, the Si atom adhesion amount on the support surface is 0.1 to 8 mg / m. ² Even in the case where a recording layer is provided on the lithographic printing plate precursor, adhesion between the recording layer and the support can be improved.
[0041]
The electrochemical surface roughening treatment is usually performed by passing a direct current or an alternating current between an aluminum plate and an electrode facing the aluminum plate using an acid such as nitric acid or hydrochloric acid as an electrolytic solution. In AC electrolysis, commercial AC sine wave (sine wave) current, special alternating current, rectangular wave current and the like can be used. The concentration of the electrolytic solution is preferably 1 to 300 g / L. Elements necessary for stabilizing the electrochemical surface roughening treatment can be appropriately added in the form of ions in an electrolytic solution such as nitric acid or hydrochloric acid.
[0042]
Crater-like or honeycomb-like pits can be generated on the surface of the aluminum alloy plate at an area ratio (dispersion density) of 30 to 100% by electrochemical surface roughening treatment. The average diameter of the pits generated by the electrochemical surface roughening treatment is usually about 0.5 to 20 μm, but in the present invention, by controlling the content of the specific element in the aluminum alloy, The average diameter is 1.2 μm or less, and the average density of pits is 1 × 10 ⁶ ~ 125 × 10 ⁶ Piece / mm ² It can be. When the average diameter and the average density of the pits are within the above ranges, the adhesion between the recording layer of the lithographic printing plate precursor and the support is excellent, and the printing durability when the lithographic printing plate is obtained is excellent. Excellent in bitterness.
[0043]
The amount of electricity used for the electrochemical surface roughening treatment is 5 to 500 C / dm in terms of the total amount of electricity in the anode reaction. ² Is preferred.
[0044]
Pits (electrolytic surface roughening pits) formed by electrochemical surface roughening have the effect of reducing stains on the non-image area of the lithographic printing plate and the printing durability of the lithographic printing plate. . In the electrochemical surface roughening treatment, by adjusting the quantity of electricity during electrolysis, that is, the product of the current during electrolysis and the time during which the current is passed, It is possible to adjust the area ratio or the like.
[0045]
In the present invention, electrochemical surface roughening treatment and other surface roughening treatment may be combined. Examples of other roughening treatment include mechanical roughening treatment and chemical roughening treatment.
For example, an electrochemical roughening treatment may be performed after a mechanical roughening treatment using a brush or the like. Examples of the mechanical surface roughening treatment include ball grain, wire grain, brush grain, and liquid honing. In addition, for example, a mechanical surface roughening treatment method described in JP-A-6-135175 and JP-B-50-40047 can be employed. When the mechanical surface roughening treatment is performed, the surface of the aluminum plate is usually converted into an average surface roughness R. _a Can be 0.35 to 1.0 μm. By performing the mechanical surface roughening treatment, the water retention of the non-image area of the planographic printing plate can be increased. However, in order to stabilize the amount of water retained in the non-image area, prevent unnecessary reflection (light reflection) of the printing plate surface during printing, and to obtain a lithographic printing plate with good workability for observing the printing state, the average surface Roughness R _a Is preferably 0.35 to 0.8 μm.
Examples of the chemical roughening treatment include a method of immersing an aluminum plate in an alkaline bath, a method of spraying an alkaline solution on the aluminum plate, and a method of applying an alkaline solution to the aluminum plate.
[0046]
Before or after each roughening treatment, the surface of the aluminum plate may be etched using an alkaline agent such as caustic soda or caustic potash. Furthermore, when an etching process is performed, a desmutting process with an acid may be performed after the etching process in order to remove an alkali-insoluble substance (smut) remaining on the surface of the aluminum plate. In particular, it is preferable to perform an etching treatment and a desmut treatment before and after the electrochemical surface roughening treatment.
[0047]
<Anodizing treatment>
Subsequent to the roughening treatment, an anodizing treatment is preferably performed in order to increase the wear resistance of the surface of the aluminum plate. Any electrolyte can be used as long as it can form a porous oxide film. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixture thereof is used. The concentration of the electrolyte is appropriately determined depending on the type of electrolyte. The conditions for anodizing treatment vary considerably depending on the electrolyte, so it is difficult to specify, but in general, the concentration of the electrolyte is 1 to 80% by mass, the liquid temperature is 5 to 70 ° C., and the current density is 1 to 60 A / dm. ² The voltage may be 1 to 100 V and the electrolysis time may be 10 to 300 seconds.
[0048]
<Hydrophilic treatment>
As described above, the aluminum plate that has been subjected to the roughening treatment and preferably further subjected to the anodization treatment is subjected to a hydrophilic treatment using an aqueous solution of an alkali metal silicate. As the hydrophilization treatment with an alkali metal silicate, various conventionally known methods can be used, but it is preferable to carry out the adhesion of the alkali metal silicate to the support surface within a predetermined range. .
In the present invention, the amount of alkali metal silicate attached to the surface of the lithographic printing plate support in terms of Si atoms (the amount of Si atoms attached) is 0.1 mg / m 2. ² The above is preferable because it is excellent in stain resistance, and 0.3 mg / m ² The above is more preferable. Further, in order to increase the hydrophilicity of the non-image area of the lithographic printing plate, when developed using a developer containing an alkali metal silicate, SiO 2 ₂ In some cases, the solid matter resulting from the precipitation may cause whitening of the non-image area during development and generation of scum or sludge during development.
On the other hand, from the standpoint of printing durability, the Si atom adhesion amount is 8 mg / m 2. ² Preferably 6 mg / m ² More preferably, it is 4 mg / m or less. ² More preferably, it is as follows.
[0049]
In the present invention, the amount of alkali metal silicate attached to the surface of the lithographic printing plate support is determined by the calibration curve method using an XRF (X-ray Fluorescence Spectrometer). (Simg / m ² ) Is used as the measured value. As a standard sample for preparing a calibration curve, a sodium silicate aqueous solution containing a known amount of Si atoms is uniformly dropped into an area of 30 mmφ on an aluminum plate and then dried. The model of the X-ray fluorescence analyzer and other conditions are not particularly limited. An example of the X-ray fluorescence X-ray analysis conditions is shown below.
[0050]
X-ray fluorescence analyzer: RIX3000 manufactured by Rigaku Corporation, X-ray tube: Rh, measurement spectrum: Si-Kα, tube voltage: 50 kV, tube current: 50 mA, slit: COARSE, spectral crystal: RX4, detector: F -PC, analysis area: 30 mmφ, peak position (2θ): 144.75 deg. , Background (2θ): 140.70 deg. And 146.85 deg. Integration time: 80 seconds / sample
[0051]
The hydrophilization treatment, for example, has a concentration of alkali metal silicate of 0.001 to 30% by mass, preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and a pH at 25 ° C. Is carried out by immersing an anodized aluminum support in an aqueous alkali metal silicate solution of 10 to 13 at 4 to 40 ° C. for 0.5 to 120 seconds, preferably 2 to 30 seconds. be able to. The processing conditions such as the alkali metal silicate concentration, pH, temperature, and processing time can be appropriately selected so that the Si atom adhesion amount becomes the specific amount. When the pH of the aqueous alkali metal silicate solution is lower than 10, the solution tends to gel, and when the pH is higher than 13.0, the anodic oxide film may be dissolved.
[0052]
Examples of the alkali metal silicate used for the hydrophilization treatment include sodium silicate, potassium silicate, and lithium silicate.
In the hydrophilization treatment, a hydroxide can be blended in order to adjust the pH of the alkali metal silicate aqueous solution as high as necessary. Examples of the hydroxide include sodium hydroxide, potassium hydroxide, and lithium hydroxide.
[0053]
Moreover, you may mix | blend an alkaline-earth metal salt and / or a group 4 (Group IVA) metal salt with alkali metal silicate aqueous solution as needed. Examples of alkaline earth metal salts include alkaline earth metal nitrates (for example, calcium nitrate, strontium nitrate, magnesium nitrate, barium nitrate), sulfate, hydrochloride, phosphate, acetate, oxalate, and boron. Water-soluble salts such as acid salts are mentioned. Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. Alkaline earth metal salts and Group 4 (Group IVA) metal salts may be used alone or in combination of two or more. The amount of these metal salts to be used is preferably 0.01 to 10% by mass, more preferably 0.05 to 5.0% by mass.
[0054]
<Flatness of lithographic printing plate support>
The lithographic printing plate support of the present invention thus obtained is cut on the lithographic printing plate support and placed on a platen as a rectangular cut sheet having a length in the plate rolling direction of 1.5 m. Place a weight covering the entire width of the cut sheet at the position inside 0.25 m from each of the sides perpendicular to the plate rolling direction, and press down the curl, and the inner length of 1 m is parallel to the plate rolling direction. The maximum height of two raised portions (distortions) is 2.0 mm or less, the number of raised portions (distortions) is 5 or less for each side, and the total height of the raised portions (distortions) is 4.0 mm or less. Is preferred. In this case, the coating property and the sheet passing property of the recording layer of the planographic printing plate support are excellent. In addition, when the corner of the cut sheet is lifted, this is also included in the number of lifted portions (distortions). In addition, on the inside of the lithographic printing plate support, the maximum height of the lifted portion (strain) is 2.0 mm or less, the number of lifted portions (strain) is 5 or less, and the total height of the lifted portion (strain) Is preferably 4.0 mm or less.
[0055]
[Recording layer (photosensitive layer)]
The recording layer of the present invention comprises (A) an alkali-soluble resin, (B) an infrared absorber that absorbs light energy such as infrared light and generates heat, and (C) a thiol compound. Below, each component which comprises this invention is demonstrated sequentially.
[0056]
<(C) Thiol compound>
The thiol compound used in the present invention is not particularly limited as long as it is a compound having at least one mercapto group (-SH) in its structure, but from the viewpoint of suppressing the odor peculiar to mercapto compounds, the molecular weight is high, A compound having low volatility is preferable. The molecular weight of such a thiol compound is preferably 90 or more, and more preferably 110 or more. Moreover, the thiol compound and aromatic thiol compound which have a some mercapto group are also preferable from a similar viewpoint.
[0057]
Furthermore, in the present invention, a thiol compound capable of tautomerization represented by the following general formula (1) is preferably used. In such a thiol compound, an alkaline aqueous solution permeates into the recording layer at the time of development, so that the thiol compound is eluted and the tautomeric equilibrium of the eluted thiol compound is on the SH side (1 side). It is presumed that there is an effect of further accelerating the solubility of the recording layer due to the bias.
[0058]
[Chemical 1]

[0059]
In formula (1), X represents a trivalent atom or atomic group, and among them, a nitrogen atom or a methine group (CH) is preferable, and a nitrogen atom is particularly preferable from the viewpoint of easily causing tautomerism.
[0060]
Examples of the thiol compound of the present invention include those having an —SH group in any of organic compounds, and those having an —SH group in a hydrocarbon compound are common. It is sufficient that at least one -SH group is present in the molecule, but it goes without saying that it may have a plurality of -SH groups.
Examples of the chain compound include those having —SH at the side chain or terminal of the aliphatic hydrocarbon. These hydrocarbon compounds may be linear or branched, and may further have a substituent such as a hydroxyl group, a halogen atom, or an amino group.
In addition, the methylene group in the hydrocarbon compound may be substituted with a divalent organic group such as ether, thioether, ester, amide, urea, thiourea.
As such a compound, for example, an —SH group is introduced at one end or both ends of a linear hydrocarbon having about 2 to 18 carbon atoms such as ethane, butane, hexane, nonane, decane, dodecane, and octadecane. Compounds, compounds in which —SH groups are introduced on carbon in hydrocarbon chains having about 2 to 18 carbon atoms, and compounds in which methine groups in these hydrocarbon chains are substituted with ether bonds or ester bonds are included. .
Examples of the cyclic compound include alicyclic hydrocarbons, aromatic hydrocarbons, condensed polycyclic hydrocarbons, and heterocyclic compounds. Moreover, you may have a 2 or more ring structure mutually independent in the molecule | numerator. In the cyclic hydrocarbon compound, the ring structure may have a substituent such as an alkyl group, a halogen atom, and a hydroxyl group in addition to the —SH group.
Examples of such compounds include compounds in which a cyclic hydrocarbon such as cyclohexane, benzene, and naphthalene is substituted with a —SH group, compounds in which a —SH group is substituted on a substituent such as an alkyl group on the cyclic hydrocarbon, and a heterocyclic ring And compounds having a substituted -SH group.
[0061]
As described above, as the thiol compound, those having a relatively large molecular weight are preferable, but in a linear hydrocarbon compound, the solubility tends to decrease when the molecular weight is increased. From the viewpoint of coating solution preparation, Those having a branched chain and those having a ring structure are preferred.
Among them, from the viewpoint that those having tautomerism are preferable as described above, aromatic thiol compounds and heterocyclic-containing thiol compounds having a conjugated double bond in the molecule are exemplified, and aromatic thiol compounds are particularly preferable.
Furthermore, so-called thione compounds having a —C═S (compounds having a structure represented by (2) in the general formula (1)), which are usually described in a form having a —SH group, are also included in the present invention. It is suitably used as a thiol compound. Examples of such a compound include thiourea compounds and thioamide compounds.
Although the specific example of the thiol compound used suitably for this invention below is shown, this invention is not limited to these.
[0062]
[Chemical 2]

[0063]
[Chemical Formula 3]

[0064]
[Formula 4]

[0065]
[Chemical formula 5]

[0066]
[Chemical 6]

[0067]
[Chemical 7]

[0068]
[Chemical 8]

[0069]
[Chemical 9]

[0070]
[Chemical Formula 10]

[0071]
The thiol compound according to the present invention is preferably added in an amount of 0.2 to 20% by mass, more preferably 0.5 to 10% by mass in the total solid content of the recording layer. When the addition amount is too small, it is difficult to obtain excellent development latitude and image contrast, and when the addition amount is too large, the film properties of the coating film tend to deteriorate.
[0072]
<(A) Alkali-soluble resin>
The (A) alkali-soluble resin used in the recording layer of the present invention includes homopolymers containing these acidic groups in the main chain and / or side chain in the polymer, copolymers thereof, or mixtures thereof. .
Among these, those having the acidic groups listed in the following (1) to (6) in the main chain and / or side chain of the polymer are preferable in terms of development resistance and solubility in an aqueous alkali solution.
[0073]
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH-R)
(3) Active imide group
[-SO ₂ NHCOR, -SO ₂ NHSO ₂ R, -CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (-SO _Three H)
(6) Phosphate group (-OPO _Three H ₂ )
[0074]
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent.
[0075]
Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), an alkali-soluble resin having (1) a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable, An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.
[0076]
As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolak resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (any of m-, p-, or m- / p-mixed) and formaldehyde, and pyrogallol and acetone Can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group in the side chain can also be used.
[0077]
Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.
[0078]
(2) As an alkali-soluble resin having a sulfonamide group, for example, a polymer composed of a minimum constituent unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Of these, low molecular weight compounds having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule are preferable. For example, the following general formulas (i) to ( and a compound represented by v).
[0079]
Embedded image

[0080]
[Where X ¹ , X ² Are each independently -O- or -NR ⁷ Represents. R ¹ , R ^Four Are each independently a hydrogen atom or CH _Three Represents. R ² , R ^Five , R ⁹ , R ¹² And R ¹⁶ Each independently represents a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a substituent. R ^Three , R ⁷ And R ¹³ Each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ , R ¹⁷ Represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group that may each independently have a substituent. R ⁸ , R ^Ten , R ¹⁴ Are each independently a hydrogen atom or CH _Three Represents. R ¹¹ , R ¹⁵ Each independently represents a C1-C12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ¹ , Y ² Each independently represents a single bond or CO. ]
[0081]
Among the compounds represented by general formula (i) to general formula (v), in the recording layer of the present invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- ( p-Aminosulfonylphenyl) acrylamide and the like can be preferably used.
[0082]
(3) As an alkali-soluble resin having an active imide group, for example, a polymer composed of a minimum constituent unit derived from a compound having an active imide group as a main constituent can be mentioned. Examples of such compounds include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.
[0083]
Embedded image

[0084]
Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.
[0085]
(4) As an alkali-soluble resin having a carboxylic acid group, for example, a polymer having as a main constituent a minimum structural unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule. Can be mentioned.
(5) The alkali-soluble polymer having a sulfonic acid group includes, for example, a polymer having a minimum structural unit derived from a compound having at least one sulfonic acid group and at least one polymerizable unsaturated group in the molecule as a main structural unit. Coalescence can be mentioned.
(6) As an alkali-soluble resin having a phosphate group, for example, a polymer whose main constituent is a minimum structural unit derived from a compound having at least one phosphate group and at least one polymerizable unsaturated group in the molecule. Can be mentioned.
[0086]
The minimum structural unit having an acidic group selected from the above (1) to (6) that constitutes the alkali-soluble resin used in the recording layer of the present invention is not necessarily limited to one kind, and has the same acidic group. It is also possible to use a copolymer obtained by copolymerizing two or more minimum structural units or two or more minimum structural units having different acidic groups.
[0087]
The copolymer preferably contains 10 mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized in order to sufficiently improve the development latitude. More preferably, 20 mol% or more is contained.
[0088]
In this invention, when copolymerizing a compound and using an alkali-soluble resin as a copolymer, the other compound which does not contain the acidic group of said (1)-(6) can also be used as a compound to copolymerize. Examples of other compounds not containing an acidic group of (1) to (6) include the compounds listed in the following (m1) to (m12), but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
[0089]
(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.
[0090]
The alkali-soluble resin preferably has a phenolic hydroxyl group from the viewpoint of excellent image forming properties when exposed to an infrared laser or the like. For example, a phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- Preferred are novolak resins and pyrogallol acetone resins such as / p-mixed cresol formaldehyde resin and phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin.
[0091]
Further, as an alkali-soluble resin having a phenolic hydroxyl group, as described in US Pat. No. 4,123,279, a carbon number of 3 such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. And a condensation polymer of phenol and formaldehyde having an alkyl group of ˜8 as a substituent.
[0092]
The alkali-soluble resin preferably has a weight average molecular weight of 500 or more from the viewpoint of image formability, and more preferably 1,000 to 700,000. The number average molecular weight is preferably 500 or more, and more preferably 750 to 650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
[0093]
Moreover, these alkali-soluble resins may be used alone or in combination of two or more. In the case of combination, it has 3 to 8 carbon atoms such as a condensation polymer of t-butylphenol and formaldehyde or a condensation polymer of octylphenol and formaldehyde as described in US Pat. No. 4,123,279. A polycondensation product of phenol and formaldehyde having an alkyl group as a substituent, an alkali having a phenol structure having an electron-withdrawing group on an aromatic ring described in JP-A-2000-241972 previously filed by the present inventors A soluble resin or the like may be used in combination.
[0094]
The total content of the alkali-soluble resin in the present invention is preferably from 30 to 98% by mass, more preferably from 40 to 95% by mass, based on the total solid content of the recording layer. When the content is 30% by mass or more, durability can be sufficiently secured, and when the content is 98% by mass or less, sensitivity and image formability can be sufficiently secured, which is preferable.
[0095]
<(B) Infrared absorber>
The infrared absorber used in the present invention is not particularly limited as long as it is a substance that absorbs infrared rays and generates heat, but from the viewpoint of compatibility with an easily available high-power laser, a wavelength of 760 nm. Preferred is an infrared absorbing dye or pigment having an absorption maximum at ˜1200 nm.
[0096]
As the dye, commercially available dyes, for example, known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, oxonol dyes And dyes such as diimonium dyes, aminium dyes, and croconium dyes.
[0097]
Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, U.S. Pat. No. 4,973,572, etc. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.
[0098]
Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .
[0099]
Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).
[0100]
Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Further, the dyes represented by the following general formulas (a) to (e) are preferable because of their excellent photothermal conversion efficiency. Particularly, the cyanine dye represented by the following general formula (a) is used in the recording layer of the present invention. Further, it is most preferable because it gives high interaction with the alkali-soluble resin and is excellent in stability and economy.
[0101]
Embedded image

[0102]
In general formula (a), X ¹ Is a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ Or the group shown below is represented. Where X ² Represents an oxygen atom or a sulfur atom, and L ¹ Represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, and a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.
[0103]
Embedded image

[0104]
R ¹ And R ² Each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ And R ² Is preferably a hydrocarbon group having 2 or more carbon atoms, and further R ¹ And R ² Are preferably bonded to each other to form a 5-membered ring or a 6-membered ring.
[0105]
Ar ¹ , Ar ² These may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ , Y ² May be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ^Three , R ^Four These may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ^Five , R ⁶ , R ⁷ And R ⁸ May be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ^- Represents a counter anion. However, R ¹ ~ R ⁸ When any of the above is substituted with a sulfo group, ^- Is not necessary. Preferred Za ^- Are halogen ions, perchlorate ions, tetrafluoroborate ions, hexafluorophosphate ions, and sulfonate ions, particularly preferably perchlorate ions, hexafluorophosphate ions, from the storage stability of the recording layer coating solution. , And aryl sulfonate ions.
[0106]
Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A-2001-133969. And those described in paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.
[0107]
Embedded image

[0108]
Embedded image

[0109]
Embedded image

[0110]
Embedded image

[0111]
In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents are bonded to each other to form a ring structure. Also good. Zb ⁺ Indicates a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Ni ⁺ , K ⁺ , Li ⁺ ) And the like. R ⁹ ~ R ¹⁴ And R ¹⁵ ~ R ²⁰ Are each independently a substituent selected from a hydrogen atom or a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group, Or it represents the substituent which combined these 2 or 3 and may combine with each other and may form the ring structure. Here, in the general formula (b), L represents a methine chain having 7 conjugated carbon atoms, and R ⁹ ~ R ¹⁴ And R ¹⁵ ~ R ²⁰ In which all represent hydrogen atoms are preferred from the viewpoint of availability and effects.
[0112]
Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.
[0113]
Embedded image

[0114]
Embedded image

[0115]
In the general formula (c), Y ^Three And Y ^Four Each represents an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{twenty one} ~ R ^{twenty four} And R ^{twenty five} ~ R ²⁸ Each may be the same or different, and may be a hydrogen atom, halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group, Or represents an amino group. In the formula, Za ^- Represents a counter anion, and Za in the general formula (a) ^- It is synonymous with.
[0116]
In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.
[0117]
Embedded image

[0118]
Embedded image

[0119]
In the general formula (d), R ²⁹ ~ R ³² Each independently represents a hydrogen atom, an alkyl group, or an aryl group. R ³³ And R ³⁴ Each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ And R ³⁰ Or R ³¹ And R ³² May be bonded to each other to form a ring, and R ²⁹ And / or R ³⁰ Is R ³³ And again R ³¹ And / or R ³² Is R ³⁴ To form a ring, and further R ³³ Or R ³⁴ R is present when there are multiple ³³ Each other or R ³⁴ They may be bonded to each other to form a ring. X ² And X ^Three Are each independently a hydrogen atom, an alkyl group, or an aryl group, and X ² And X ^Three At least one of represents a hydrogen atom or an alkyl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ^- Represents a counter anion, and Za in the general formula (a) ^- It is synonymous with.
[0120]
In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.
[0121]
Embedded image

[0122]
Embedded image

[0123]
In the general formula (e), R ³⁵ ~ R ⁵⁰ Are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group which may have a substituent. , Amino group, onium salt structure. R ³⁶ And R ³⁷ , R ⁴⁰ And R ⁴¹ , R ⁴⁴ And R ⁴⁵ And R ⁴⁸ And R ⁴⁹ May be linked to form an aliphatic ring, an aromatic ring or a heterocyclic ring, and the ring may have a condensed ring. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein are IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.
[0124]
In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.
[0125]
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[0126]
Examples of pigments used as infrared absorbers in the present invention include commercially available pigments and Color Index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology”. (CMC Publishing, published in 1986) and “Printing Ink Technology”, published by CMC Publishing, published in 1984).
[0127]
Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.
[0128]
These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.
[0129]
The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. The particle size of the pigment is preferably 0.01 μm or more from the viewpoint of the stability of the dispersion in the image recording layer coating solution, and is preferably 10 μm or less from the viewpoint of the uniformity of the recording layer.
[0130]
As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).
[0131]
These pigments or dyes are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, particularly preferably 0.5 to 10% by mass, and pigments, based on the total solid content of the recording layer. Especially preferably, it can add in the ratio of 0.1-10 mass%. When the added amount of the pigment or dye is 0.01% by mass or more, sufficient sensitivity can be secured, and by setting the amount to 50% by mass or less, the uniformity of the recording layer and the recording layer film Strength can be maintained.
[0132]
[Positive recording layer]
The recording layer of the present invention is applied to a lithographic printing plate precursor as a positive recording layer whose solubility in an aqueous alkali solution is improved by infrared laser exposure. Examples of the positive recording layer include an interaction release type recording layer and an acid catalyst decomposition type recording layer. These recording layers can be used in a multilayer configuration. For example, a recording layer composed of two layers of interaction release system, a two-layer structure composed of an interaction system and an acid catalyst decomposition system, and the like can be mentioned. In the case where the acid catalyst decomposition system is provided in a plurality of layers as one layer in the multilayer structure, it is particularly preferable that the acid catalyst decomposition system is formed as the uppermost layer of the exposure surface.
[0133]
<Interaction release system>
The interaction release system recording layer is a layer containing (A) an alkali-soluble resin and (B) an infrared absorber, and the alkali-soluble resin forming the recording layer by thermal energy generated by light irradiation or heating. The interaction such as the association is released, the solution becomes soluble in an alkaline aqueous solution, and is removed by development to form a non-image portion. At that time, by allowing the thiol compound (C) of the present invention to coexist, good discrimination is imparted.
A known compound other than the components (A), (B), and (C) can be used in combination in the recording layer of the interaction release system of the present invention as desired.
[0134]
<Acid catalyst decomposition system>
In addition to the components (A), (B) and (C), the recording layer of the acid catalyst decomposition system catalyzes a compound (acid generator) that generates acid by the action of light or heat, and the generated acid. The layer contains a compound (acid-decomposable compound) that cleaves a chemical bond and increases the solubility in an alkaline developer as an essential component. In this system, (A) the alkali-soluble resin mainly functions as a binder polymer.
Due to such an acid-catalyzed decomposition mechanism, the acid-catalyzed decomposition-type image forming material is also referred to as a chemically amplified image-forming material.
[0135]
<Acid-decomposable compound>
In the present invention, the compound that cleaves a chemical bond using an acid as a catalyst and increases the solubility in an alkaline developer can be referred to as a compound having a bonding group that can be decomposed by an acid in the molecule. As such a compound, those described in Japanese Patent Application Laid-Open No. 9-171254 as “a compound having at least one bond that can be decomposed by an acid” can be used. Preferred examples of the bond that can be decomposed by an acid include an acetal bond and a ketal bond.
Among such compounds, it is more preferable to use a compound represented by the following general formula (I) from the viewpoint of sensitivity and developability.
[0136]
Embedded image

[0137]
In general formula (I), R ¹ , R ² And R ^Three Each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, a carboxyl group or a hydroxyl group, and p, q and r are each an integer of 1 to 3 M and n each represents an integer of 1 to 5.
[0138]
In general formula (I), R ¹ , R ² And R ^Three The alkyl group represented by may be linear or branched, and examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, and a pentyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Group, propoxy group, isopropoxy group, butoxy group, tert-butoxy group, pentoxy group and the like, and sulfo group and carboxyl group include salts thereof. Of the compounds represented by formula (I), compounds in which m and n are 1 or 2 are particularly preferred. The compound represented by the general formula (I) can be synthesized by a known method.
[0139]
Other acid-decomposable compounds that can be applied to the present invention include JP-A-48-89603, 51-120714, 53-133429, 55-12995, 55-126236, 56- Compounds having C—O—C bonds described in JP-A No. 17345, compounds having Si—O—C bonds described in JP-A Nos. 60-37549 and 60-121446, JP-A Nos. 60-3625, Other acid-decomposing compounds described in JP-A-60-10247 can be listed, and further compounds having an Si-N bond described in JP-A-62-2222246, described in JP-A-62-2251743 Carbonic acid esters, ortho-carbonic acid esters described in JP-A-62-209451, ortho-titanic acid esters described in JP-A-62-280841 Ter, orthosilicate esters described in JP-A-62-280842, JP-A-63-1010153, JP-A-10-55067, JP-A-10-111564, JP-A-10-87733, and JP-A-10-153853 10-228102, 10-268507, 282648, 10-282670, acetals, ketals and orthocarboxylic acid esters described in EP-088547547Al, described in JP-A-62-244038 A compound having a C—S bond can be used.
[0140]
Among these acid-decomposable compounds, JP-A-53-133429, JP-A-56-17345, JP-A-60-121446, JP-A-60-37549, JP-A-62-209451, JP-A-63-010153, JP-A-10 -55067, 10-111564, 10-87733, 10-153835, 10-228102, 10-268507, 282648, 10-282670, EP 08484747Al Preferred are compounds having a C—O—C bond, compounds having a Si—O—C bond, orthocarbonates, acetals, ketals and silyl ethers.
Among these acid-decomposable compounds, a high molecular compound that has an acetal or ketal moiety repeatedly in the main chain and increases in solubility in an alkali developer is preferably used.
[0141]
These acid-decomposable compounds may be used alone or in combination of two or more. Moreover, as addition amount, 5-70 mass% with respect to chemical amplification layer total solid, Preferably it is 10-50 mass%, More preferably, it adds to a layer in the ratio of 15-35 mass%. It is preferable that the addition amount be 5% by mass or more because the non-image area is not stained, and the addition amount is 70% by mass or less because the film strength of the image part can be maintained.
[0142]
<Acid generator>
The compound that generates an acid by light or heat (acid generator) refers to a compound that decomposes when irradiated with infrared rays or heated at 100 ° C. or more to generate an acid. The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid.
[0143]
Examples of the acid generator suitably used in the present invention include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and diazonium salts. Specific examples include compounds described in US Pat. No. 4,708,925 and JP-A-7-20629. In particular, iodonium salts, sulfonium salts, and diazonium salts having a sulfonate ion as a counter ion are preferable. Examples of the diazonium salt include a diazonium compound described in US Pat. No. 3,867,147, a diazonium compound described in US Pat. No. 2,632,703, and JP-A-1-102456 and JP-A-1-102457. The diazo resin described in 1 is also preferable. Further, benzyl sulfonates described in US Pat. No. 5,135,838 and US Pat. No. 5,200,544 are also preferable. Furthermore, active sulfonic acid esters and disulfonyl compounds described in JP-A-2-100054, JP-A-2-100055 and JP-A-9-197671 are also preferred. In addition, haloalkyl-substituted S-triazines described in JP-A-7-271029 are also preferable.
[0144]
The content of the photoacid generator in the present invention can vary widely depending on its chemical properties and the composition or physical properties of the recording layer of the present invention, but it is about 0.1 to about 20 mass relative to the solid content of the recording layer. % Range is appropriate, preferably 0.2 to 10% by mass.
[0145]
<Other ingredients>
Various additives can be further added to the above-described recording layer of the present invention as necessary.
For example, when other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. are added, so-called dissolution improves the function of preventing dissolution of alkaline water-soluble polymers (alkali-soluble resins) in the developer. It is preferable to add a deterrent agent. Among them, a substance that is thermally decomposable, such as an onium salt, an o-quinonediazide compound, and a sulfonic acid alkyl ester, and that substantially reduces the solubility of the alkali-soluble resin when not decomposed is used in combination. It is preferable to improve the inhibition of dissolution of the image area in the developer. As the decomposable dissolution inhibitor, onium salts such as diazonium salts, iodonium salts, sulfonium salts, ammonium salts, and o-quinonediazide compounds are preferable, and diazonium salts, iodonium salts, and onium salts of sulfonium salts are more preferable.
[0146]
Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
Among these onium salts, diazonium salts are particularly preferable from the viewpoints of dissolution inhibiting ability and thermal decomposability. In particular, the diazonium salt represented by the general formula (I) described in JP-A No. 5-158230 and the diazonium salt represented by the general formula (1) described in JP-A No. 11-143064 are preferable. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength is most preferable.
[0147]
The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.
[0148]
Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid ester or sulfonic acid amide is preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.
[0149]
Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.
[0150]
The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, particularly preferably the total solid content of the recording layer. Is in the range of 1-2% by weight. These compounds can be used alone, but may be used as a mixture of several kinds.
[0151]
The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.
[0152]
Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.
[0153]
As another additive, cyclic acid anhydrides, phenols, and organic acids can be used in combination for the purpose of improving sensitivity. Further, surfactants, image colorants, and plasticizers described later are also additives that can be used.
[0154]
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 '' -Trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. Further, examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Is mentioned.
[0155]
The proportion of the cyclic acid anhydride, phenols and organic acids in the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10%. % By mass.
[0156]
In addition to these, a crosslinkable compound having an alkaline dissolution inhibiting effect described in JP-A-11-160860 previously proposed by the present inventors can be appropriately added depending on the purpose.
[0157]
Further, in the recording layer coating liquid according to the present invention, in order to widen the processing stability against the developing conditions, nonionic ions as described in JP-A-62-251740 and JP-A-3-208514 are used. Surfactants, amphoteric surfactants as described in JP-A-59-121044, JP-A-4-13149, siloxane compounds as described in EP950517, JP-A-11-288093 Fluorine-containing monomer copolymers such as those described in the publication can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.
[0158]
Further, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
A representative example of the print-out agent is a combination of a compound that generates an acid (photo acid generator) upon heating by exposure and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, No. -36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.
[0159]
As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, oil yellow # 101, oil yellow # 103, oil pink # 312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the recording layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the recording layer.
[0160]
Furthermore, a plasticizer is added to the recording layer as needed to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.
[0161]
[Formation of planographic printing plate precursor]
When the recording layer of the present invention is applied to a lithographic printing plate precursor, it can be produced by dissolving the recording layer component in a solvent and coating the solution on a suitable support.
Further, depending on the purpose, a resin intermediate layer, an undercoat layer, a backcoat layer and the like, which will be described later, can be formed in the same manner.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally speaking, it is 0.5 to 5.0 g / m for a lithographic printing plate precursor. ² Is preferred. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer decrease.
Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
[0162]
In the recording layer of the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant as described in JP-A No. 62-170950 can be added. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in the total solid content of the recording layer.
[0163]
The lithographic printing plate precursor according to the present invention can be provided with a resin intermediate layer between the support and the recording layer, if necessary.
By providing this resin intermediate layer, the resin intermediate layer made of a polymer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the exposure of the infrared laser does not diffuse to the support efficiently. Since it is used, there is an advantage that high sensitivity can be achieved. Further, since the recording layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the resin intermediate layer is provided, the sensitivity to the infrared laser is maintained well.
In the unexposed area, the recording layer itself that is impermeable to the alkali developer functions as a protective layer for the resin intermediate layer, so that the development stability is good and the image is excellent in discrimination. In the exposed area, the components of the recording layer whose dissolution inhibiting ability has been released are quickly dissolved and dispersed in the developer. Since this resin intermediate layer itself that is adjacent to the support is made of an alkali-soluble polymer, it has good solubility in a developer, for example, even when a developer with reduced activity is used. It is considered that this resin intermediate layer is useful because it dissolves quickly without generating a film and the like and contributes to improvement of developability.
[0164]
The lithographic printing plate precursor according to the invention has a recording layer provided on a support, and an undercoat layer can be provided between the recording layers as necessary.
Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Hydroxy such as salt -Alanine, and hydrochlorides of amines having a group may be used in combination of two or more.
[0165]
Moreover, as a suitable undercoat layer component in the present invention, there can be mentioned a polymer compound having a component having an acid group and a component having an onium group, as described in JP-A No. 2000-241962. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or less, more preferably —COOH, —SO. _Three H, -OSO _Three H, -PO _Three H ₂ , -OPO _Three H ₂ , -CONHSO ₂ -, Or -SO ₂ NHSO ₂ -, Particularly preferably -COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium group is an onium group composed of Group V or Group VI atoms of the Periodic Table, more preferably an onium group composed of a nitrogen atom, a phosphorus atom or a sulfur atom, and particularly preferably a nitrogen atom. Is an onium group. Specific examples of the monomer having an onium group include styrene having a substituent containing an onium group such as methacrylate, methacrylamide, or quaternary ammonium group having a quaternary ammonium group in the side chain.
[0166]
This organic undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the organic compound in an organic solvent or a mixed solvent thereof to adsorb the compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution of the organic compound having a concentration of 0.005 to 10% by mass can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.
The coverage of the organic undercoat layer is 2 to 200 mg / m ² Is suitable, preferably 5 to 100 mg / m ² It is. The coating amount is 2 to 200 mg / m ² As a result, sufficient printing durability can be obtained.
[0167]
A back coat can be provided on the back side of the support of the lithographic printing plate precursor according to the invention, if necessary. Examples of such back coats include organic polymer compounds described in JP-A-5-45885 and metal oxides obtained by hydrolysis and polycondensation of organic or inorganic metal compounds described in JP-A-6-35174. A covering layer is mentioned. Of these coating layers, Si (OCH _Three ) _Four , Si (OC ₂ H _Five ) _Four , Si (OC _Three H ₇ ) _Four , Si (OC _Four H ₉ ) _Four A silicon alkoxy compound such as the above is inexpensive and easily available, and a metal oxide coating layer obtained therefrom is particularly preferable because of its excellent developer resistance.
[0168]
[Plate making and printing]
The planographic printing plate precursor of the present invention is image-formed by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.
[0169]
The exposed lithographic printing plate precursor of the present invention is subjected to development treatment and post-treatment with a finisher, a protective gum, or the like to form a printing plate. For these processes, a known processing apparatus such as an automatic processor can be used.
The processing agent used in the development processing and post-processing of the lithographic printing plate precursor according to the invention can be appropriately selected from known processing agents.
[0170]
A suitable developer is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used as the developer. Among the above alkaline aqueous solutions, as a particularly suitable developer, a so-called “well-known”, which contains an alkali silicate as a base, or contains an alkali silicate by mixing a silicon compound with a base. An aqueous solution called “silicate developer” having a pH of 12 or higher, and non-reducing sugars (organic compounds having a buffering action) that do not contain an alkali silicate and are described in JP-A-8-305039 and JP-A-11-109637 And a so-called “non-silicate developer” containing a base.
[0171]
When the lithographic printing plate of the present invention is burned, it is preferably carried out by a conventionally known method using a burning surface-conditioning liquid and using a burning processor or the like.
[0172]
The lithographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.
[0173]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In Examples of the present application, an evaluation is performed on a lithographic printing plate precursor using the resin composition of the present invention as a recording layer, and the evaluation is regarded as an evaluation of the resin composition of the present invention.
・ Manufacture of lithographic printing plate precursors
Each aluminum plate having the composition shown in Table 1 was subjected to various surface treatments to obtain lithographic printing plate supports.
[Table 1]

[0174]
(A) Mechanical roughening treatment
While a suspension of a polishing agent (silica sand) having a specific gravity of 1.12 and water was supplied to the surface of the aluminum plate as a polishing slurry, mechanical surface roughening was performed with a rotating roller-like nylon brush. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The number of rotations of the brush was 250 rpm for the first, and 200 rpm for the second and third.
[0175]
(B) Alkali etching treatment
The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration: 26 mass%, aluminum ion concentration: 5 mass%) to carry out an etching treatment. ² Dissolved. Thereafter, washing with water was performed using well water.
[0176]
(C) Desmut treatment
A desmut treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid having a nitric acid concentration of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.
[0177]
(D) Electrochemical roughening treatment
An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density is 30 A / dm at the peak current value. ² The amount of electricity is 175 C / dm as the total amount of electricity when the aluminum plate is the anode. ² Met. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.
[0178]
(E) Alkali etching treatment
The aluminum plate was etched at 32 ° C. with a caustic soda concentration of 26 mass% and an aluminum ion concentration of 5 mass%, and the aluminum plate was 0.5 g / m. ² Dissolve and remove the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening was performed using alternating current in the previous stage, and dissolve the edge part of the generated pit to produce the edge part Made smooth. Thereafter, washing with water was performed using well water.
[0179]
(F) Desmut treatment
A desmut treatment was performed by spraying with an aqueous solution of sulfuric acid having a concentration of sulfuric acid at a temperature of 30 ° C. and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.
[0180]
(G) Electrochemical roughening treatment
An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolyte at this time was a hydrochloric acid 5.0 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density is 25 A / dm at the peak current value. ² The amount of electricity is 50 C / dm as the total amount of electricity when the aluminum plate is the anode. ² Met. Thereafter, washing with water was performed using well water.
[0181]
(H) Alkali etching treatment
The aluminum plate was etched by spraying at 32 ° C. with an NaOH concentration of 5 mass% and an aluminum ion concentration of 0.5 mass%, and the aluminum plate was 0.10 g / m. ² Dissolves and removes the smut component mainly composed of aluminum hydroxide generated when electrochemical roughening treatment is performed using the alternating current of the previous stage, and dissolves the edge part of the generated pit The part was smoothed. Thereafter, washing with water was performed using well water.
[0182]
(I) Desmut treatment
Desmutting treatment was performed by spraying with a 25% by mass sulfuric acid concentration aqueous solution at a temperature of 60 ° C., and then water washing by spraying using well water.
[0183]
(J) Anodizing treatment
Sulfuric acid was used as the electrolytic solution. All electrolytes had a sulfuric acid concentration of 150 g / liter (containing 0.5 mass% of aluminum ions) and a temperature of 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities are about 30 A / dm ² Met. The final oxide film amount is 2.5 g / m ² Met.
[0184]
(K) Silicate processing
A silicate treatment by dipping was performed with a No. 3 sodium silicate aqueous solution at a temperature of 35 ° C., followed by washing with water using well water.
[0185]
<Support X>
Each process of said (a)-(k) was performed in order, and the support body was produced. (E) The etching amount in the process is 0.5 g / m. ² It set so that it might become.
<Support Y>
Except for omitting the steps (g), (h) and (i) among the above steps, each step was performed in order to prepare a support.
<Support Z>
A support was prepared by sequentially performing each step except that the steps (a), (g), (h), and (i) were omitted. The etching amount in the step (e) is 3.5 g / m. ² Changed to
[0186]
(Undercoating)
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying is 15 mg / m ² Met.
[0187]
<Undercoat liquid composition>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1.0g
[0188]
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[0189]
[Examples 1-7, Comparative Examples 1-9]
After applying the undercoat liquid to the obtained supports X to Z, a lower layer coating liquid having the following composition was applied at a wet coating amount of 18.75 ml / m. ² After being coated with a wire bar, it was dried in a drying oven at 130 ° C. for 50 seconds. Lower layer coverage after drying is 0.85 g / m ² Met.
On the obtained support with a lower layer, a coating solution 2 for an image recording layer (upper layer) having the following composition was applied at a wet coating amount of 18.75 ml / m. ² Coating with a wire bar of 1.10 g / m ² It was. After coating, drying was performed at 140 ° C. for 60 seconds in a drying oven to prepare a positive planographic printing plate precursor.
[0190]

[0191]

[0192]
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[0193]
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[0194]
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[0195]
What was obtained using the photosensitive layer which does not add a thiol compound to the lower layer was used as a lithographic printing original plate a, and what was obtained using a photosensitive layer to which C-1 was added to the lower layer was used as a lithographic printing original plate b and C- A lithographic printing original plate c was obtained using the photosensitive layer with 2 added, and a lithographic printing original plate d was obtained using the photosensitive layer with C-3 added to the lower layer.
[0196]
[Evaluation of sensitivity]
The obtained lithographic printing original plate was drawn at a rotation speed of 150 rpm with a Trend setter 3244 manufactured by Creo Co., Ltd., and the laser output was changed from 3 to 8 W in steps of 0.25 W while changing the exposure energy. After that, diluted with 8 parts of water to 1 part of a developer for thermal positive (DT-2 manufactured by Fuji Photo Film Co., Ltd.) in a developing bath of LP-940H (automatic developing machine manufactured by Fuji Photo Film Co., Ltd.) 20 liters of the resulting solution was kept at 30 ° C., 8 liters of tap water was used in the second bath, and 1 part of finishing gum (FG-1 manufactured by Fuji Photo Film Co., Ltd.) was used in the third bath. 8 liters of the diluted solution was added. The development speed was set so that the development time was 12 seconds. The exposure amount (beam intensity at a drum rotation speed of 150 rpm) that can develop the non-image area with the developer was measured and used as sensitivity. The smaller the numerical value, the higher the sensitivity.
[0197]
A printing test was performed on the obtained lithographic printing plate, and printing durability and resistance to soiling were evaluated as follows.
[Evaluation of printing durability]
As a printing machine, use a Mitsubishi Diamatic printing machine, use Dios G (S) black as the ink, and use EU-3 (1: 100) manufactured by Fuji Photo Film Co., Ltd. as the dampening water. Printing was performed using the liquid added so as to be 7% by mass.
Evaluation was made based on the number of printed sheets until the solid image portion started to be faintly thinly observed. The printing durability was shown as a relative value with the printing durability of Example 1 as 100.
[0198]
[Dust resistance]
As a printing machine, use a Mitsubishi Diamatic printing machine, use Dios G (S) red as ink, and use EU-3 (1: 100) manufactured by Fuji Photo Film Co., Ltd. as the dampening water. Printing was performed using the liquid added so as to be 7% by mass. At the time of printing, the stain on the non-image area generated on the blanket facing the plate was transferred to a cellophane tape, collected, and evaluated according to the degree of ink adhesion. In order from the ink-free one to the one with many inks, ◎, ○, Δ, and × were given.
These results are shown in Table 2.
[0199]
[Table 2]

[0200]
From Table 2, the copper content is 0.005% by mass or less, the average diameter of pits on the surface is 1.2 μm or less, and the average density of pits is 1 × 10 ⁶ ~ 125 × 10 ⁶ Piece / mm ² It can be seen that only an example having a recording layer to which a thiol compound is added on an aluminum support can achieve high sensitivity while maintaining a balance between printing durability and stain. When no thiol compound is added to the recording layer, the sensitivity is low. Further, it is clear that those having a larger pit diameter and lower average pit density than the above support have low printing performance (printing durability, stain).
[0201]
[Example 8, Comparative Examples 10-11]
On the supports obtained in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 9, the following image recording layer coating solution 1 was applied, and then dried in a drying oven at 150 ° C. for 1 minute to obtain a dry film. Thickness 1.8g / m ² A lithographic printing plate precursor having a positive image recording layer was prepared.
[0202]

[0203]
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[0204]
A lithographic printing plate precursor e was obtained using a photosensitive layer to which no thiol compound was added, and a lithographic printing plate f was obtained using a photosensitive layer to which a thiol compound C-1 was added.
[0205]
[Evaluation of sensitivity]
The obtained original plate for lithographic printing was drawn with a writing setter 3244 manufactured by Creo at a writing speed of 150 rpm, and the laser output was changed in 3 to 8 W at 0.25 W increments and the exposure energy was changed. Thereafter, a developer for thermal positive (LH-DS manufactured by Fuji Photo Film Co., Ltd.) was charged into the development processing bath of FLH-85N (Fuji Photo Film Co., Ltd. automatic developing machine) and kept at 28 ° C. In the second bath, tap water was added, and in the third bath, 8 liters of a solution obtained by diluting 1 part of finishing gum (FN-6 manufactured by Fuji Photo Film Co., Ltd.) with 1 part of water was charged. The development speed was set so that the development time was 26 seconds. The exposure amount (beam intensity at a drum rotation speed of 150 rpm) that can develop the non-image area with the developer was measured and used as sensitivity. The smaller the numerical value, the higher the sensitivity.
[0206]
[Evaluation of printing durability and dirt]
Printing durability and stains were evaluated in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 9.
These results are shown in Table 3.
[0207]
[Table 3]

[0208]
From Table 3, it can be seen that Example 8 having the support according to the present invention and the recording layer containing a thiol compound can achieve high sensitivity while maintaining the balance between printing durability and stain.
[0209]
[Examples 9 to 10]
The lithographic printing plate precursor used in Example 5 and Example 8 was exposed at 150 rpm with a Trendsetter 3244 manufactured by Creo. Then, using 900H (Fuji Photo Film Co., Ltd. PS processor) charged with the following alkaline developer A composition, the liquid temperature was kept at 28 ° C., and the sample of Example 5 (Example 9) was carried out for 10 seconds. Example 8 (Example 10) was developed in 20 seconds. About these, sensitivity, printing durability, and stain | pollution | contamination were evaluated like Example 1-7 and Comparative Examples 1-9. The results are shown in Table 4.
[0210]

[0211]
[Table 4]

[0212]
From the results shown in Table 4, the lithographic printing plate precursor of the present invention is excellent in sensitivity and printing performance not only in the non-silicate type, but also in the case of using a silicate type developer such as A composition. Was confirmed.
[0213]
【The invention's effect】
According to the present invention, it is possible to provide a lithographic printing plate precursor excellent in good sensitivity, printing durability and resistance to stains. In addition, a lithographic printing plate precursor that can be satisfactorily processed even with a developer containing no alkali metal silicate can be provided.

Claims (1)

The copper content of the raw material aluminum alloy is 0.005% by mass or less, surface roughening treatment including electrochemical surface roughening treatment is performed, the average diameter of the surface pits is 1.2 μm or less, A recording layer containing (A) an alkali-soluble resin, (B) an infrared absorber, and (C) a thiol compound on an aluminum support having an average density of 1 × 10 ^{6 to} 125 × 10 ⁶ pieces / mm ^2. A positive lithographic printing plate precursor comprising: