JP2004333814A - Photosensitive planographic printing plate material and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive planographic printing plate material adaptable to laser exposure in the region of 350-450 nm and excellent in high sensitivity, high printing durability, staining property, suitability to a plate cleaner and dot reproducibility and to provide an image forming method for the same. <P>SOLUTION: In the photosensitive planographic printing plate material obtained by coating the top of a support subjected to at least surface roughening and anodic oxidation with a photosensitive composition containing a photopolymerization initiator, a polymer binder, an addition polymerizable monomer containing an ethylenically unsaturated bond, and a sensitizing dye having an absorption maximum between 350 and 450 nm, the support has a finely rough surface having a surface roughness Ra of 0.4-0.8 μm, where the number of peaks having an average interval or an average diameter of 30-150 nm is 50-1,100/μm<SP>2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５８】
好ましくは、２−ヒドロキシエチルメタクリレート、２−ヒドロキシエチルアクリレート、４−ヒドロキシブチルアクリレート、２−ヒドロキシプロピレン−１，３−ジメタクリレート、２−ヒドロキシプロピレン−１−メタクリレート−３−アクリレート等が挙げられる。
【００５９】
これらの反応は、通常のジオール化合物、ジイソシアネート化合物、ヒドロキシル基含有アクリレート化合物の反応で、ウレタンアクリレートを合成する方法と同様に行うことが出来る。
【００６０】
本発明の感光性組成物及び感光性平版印刷版材料に用いられる付加重合可能なエチレン性不飽和結合含有単量体は上記以外に一般的なラジカル重合性のモノマー類、紫外線硬化樹脂に一般的に用いられる分子内に付加重合可能なエチレン性二重結合を複数有する多官能モノマー類や、多官能オリゴマー類を併用することができる。具体的な化合物としては、例えば、２−エチルヘキシルアクリレート、２−ヒドロキシプロピルアクリレート、グリセリルアクリレート、テトラヒドロフルフリルアクリレート、フェノキシエチルアクリレート、ノニルフェノキシエチルアクリレート、テトラヒドロフルフリルオキシエチルアクリレート、テトラヒドロフルフリルオキシヘキシルアクリレート、或いはこれらのアクリレートをメタクリレート、イタコネート、クロトネート、マレエートに代えたメタクリル酸エステル、イタコン酸エステル、クロトン酸エステル、マレイン酸エステル；更には例えば、エチレングリコールジアクリレート、トリエチレングルコールジアクリレート、ペンタエリスリトールジアクリレート、ハイドロキノンジアクリレート、レゾルシンジアクリレート、ヘキサンジオールジアクリレート、ネオペンチルグリコールジアクリレート、トリプロピレングリコールジアクリレート、ヒドロキシピバリン酸ネオペンチルグリコールのジアクリレート、ネオペンチルグリコールアジペートのジアクリレート、ヒドロキシピバリン酸ネオペンチルグリコールのε−カプロラクトン付加物のジアクリレート、２−（２−ヒドロキシ−１，１−ジメチルエチル）−５−ヒドロキシメチル−５−エチル−１，３−ジオキサンジアクリレート、トリシクロデカンジメチロールアクリレート、トリシクロデカンジメチロールアクリレートのε−カプロラクトン付加物、１，６−ヘキサンジオールのジグリシジルエーテルのジアクリレート等の２官能アクリル酸エステル類、或いはこれらのアクリレートをメタクリレート、イタコネート、クロトネート、マレエートに代えたメタクリル酸エステル、イタコン酸エステル、クロトン酸エステル、マレイン酸エステル、；更には例えば、トリメチロールプロパントリアクリレート、ジトリメチロールプロパンテトラアクリレート、トリメチロールエタントリアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールテトラアクリレート、ジペンタエリスリトールテトラアクリレート、ジペンタエリスリトールペンタアクリレート、ジペンタエリスリトールヘキサアクリレート、ジペンタエリスリトールヘキサアクリレートのε−カプロラクトン付加物、ピロガロールトリアクリレート、プロピオン酸・ジペンタエリスリトールトリアクリレート、プロピオン酸・ジペンタエリスリトールテトラアクリレート、ヒドロキシピバリルアルデヒド変性ジメチロールプロパントリアクリレート等の多官能アクリル酸エステル酸、およびこれらのＥＯ変性体、或いはこれらのアクリレートをメタクリレート、イタコネート、クロトネート、マレエートに代えたメタクリル酸、イタコン酸エステル、クロトン酸エステル、マレイン酸エステル等；を挙げることができる。
【００６１】
また、プレポリマーも上記同様に使用することができる。プレポリマーとしては、後述する様な化合物等が挙げることができ、また、適当な分子量のオリゴマーにアクリル酸、又はメタクリル酸を導入し、光重合性を付与したプレポリマーも好適に使用できる。これらプレポリマーは、１種又は２種以上を併用してもよいし、上述の単量体及び／又はオリゴマーと混合して用いてもよい。
【００６２】
プレポリマーとしては、例えばアジピン酸、トリメリット酸、マレイン酸、フタル酸、テレフタル酸、ハイミック酸、マロン酸、こはく酸、グルタール酸、イタコン酸、ピロメリット酸、フマル酸、グルタール酸、ピメリン酸、セバシン酸、ドデカン酸、テトラヒドロフタル酸等の多塩基酸と、エチレングリコール、プロピレングルコール、ジエチレングリコール、プロピレンオキサイド、１，４−ブタンジオール、トリエチレングリコール、テトラエチレングリコール、ポリエチレングリコール、グリセリン、トリメチロールプロパン、ペンタエリスリトール、ソルビトール、１，６−ヘキサンジオール、１，２，６−ヘキサントリオール等の多価のアルコールの結合で得られるポリエステルに（メタ）アクリル酸を導入したポリエステルアクリレート類；例えば、ビスフェノールＡ・エピクロルヒドリン・（メタ）アクリル酸、フェノールノボラック・エピクロルヒドリン・（メタ）アクリル酸のようにエポキシ樹脂に（メタ）アクリル酸を導入したエポキシアクリレート類；例えば、エチレングリコール・アジピン酸・トリレンジイソシアネート・２−ヒドロキシエチルアクリレート、ポリエチレングリコール・トリレンジイソシアネート・２−ヒドロキシエチルアクリレート、ヒドロキシエチルフタリルメタクリレート・キシレンジイソシアネート、１，２−ポリブタジエングリコール・トリレンジイソシアネート・２−ヒドロキシエチルアクリレート、トリメチロールプロパン・プロピレングリコール・トリレンジイソシアネート・２−ヒドロキシエチルアクリレートのように、ウレタン樹脂に（メタ）アクリル酸を導入したウレタンアクリレート；例えば、ポリシロキサンアクリレート、ポリシロキサン・ジイソシアネート・２−ヒドロキシエチルアクリレート等のシリコーン樹脂アクリレート類；その他、油変性アルキッド樹脂に（メタ）アクリロイル基を導入したアルキッド変性アクリレート類、スピラン樹脂アクリレート類；等のプレポリマーが挙げられる。
【００６３】
また、本発明の感光性平版印刷版材料の光重合性感光層に用いられる本発明に係る単量体として、ホスファゼンモノマー・トリエチレングリコール・イソシアヌール酸ＥＯ（エチレンオキシド）変性ジアクリレート、イソシアヌール酸ＥＯ変性トリアクリレート、ジメチロールトリシクロデカンジアクリレート、トリメチロールプロパンアクリル酸安息香酸エステル、アルキレングリコールタイプアクリル酸変性・ウレタン変性アクリレート等の単量体及び該単量体から形成される構成単位を有する付加重合性のオリゴマー及びプレポリマーを挙げることができる。
【００６４】
更に、本発明の感光性平版印刷版材料の光重合性感光層に用いられる本発明に係る単量体として、少なくとも一つの（メタ）アクリロイル基を含有するリン酸エステル化合物が挙げられる。該化合物は、リン酸の水酸基の少なくとも一部がエステル化された化合物であり、しかも、（メタ）アクリロイル基を有する限り特に限定はされない。
【００６５】
この他に特開昭５８−２１２９９４号公報、同６１−６６４９号公報、同６２−４６６８８号公報、同６２−４８５８９号公報、同６２−１７３２９５号公報、同６２−１８７０９２号公報、同６３−６７１８９号公報、特開平１−２４４８９１号公報等に記載の化合物などを挙げることができ、更に「１１２９０の化学商品」化学工業日報社 ｐ．２８６〜ｐ．２９４に記載の化合物、「ＵＶ・ＥＢ硬化ハンドブック（原料編）」高分子刊行会 ｐ．１１〜６５に記載の化合物なども本発明においては好適に用いることができる。これらの中で、分子内に２以上のアクリル基又はメタクリル基を有する化合物が本発明においては好ましく、更に分子量が１０，０００以下、より好ましくは５，０００以下のものが好ましい。
【００６６】
本発明の感光性平版印刷版材料には、上記した本発明に係る単量体またはその他の単量体を該感光層の感光性組成物において、１．０〜８０．０質量％の範囲で含有するのが好ましく、より好ましくは３．０〜７０．０質量％の範囲である。
【００６７】
本発明の感光性平版印刷版材料の光重合性感光層の塗布組成物には、上記した成分の他に、感光性平版印刷版材料の製造中あるいは保存中において重合可能なエチレン性不飽和二重結合単量体の不要な重合を阻止するために、ヒンダードフェノール系化合物、ヒンダードアミン系化合物およびその他の重合防止剤を添加してもよい。
【００６８】
ヒンダードフェノール系化合物の例としては、２，６−ジ−ｔ−ブチル−ｐ−クレゾール、ブチル化ヒドロキシアニソール、２，２′−メチレンビス（４−メチル−６−ｔ−ブチルフェノール）、４，４′−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）、テトラキス−［メチレン−３−（３′，５′−ジ−ｔ−ブチル−４′−ヒドロキシフェニル）プロピオネート］メタン、ビス［３，３′−ビス−（４′−ヒドロキシ−３′−ｔ−ブチルフェニル）ブチリックアシッド］グリコールエステル、２−ｔ−ブチル−６−（３−ｔ−ブチル−２−ヒドロキシ−５−メチルベンジル）−４−メチルフェニルアクリレート、２−［１−（２−ヒドロキシ−３，５−ジ−ｔ−ペンチルフェニル）エチル］−４，６−ジ−ｔ−ペンチルフェニルアクリレート等が挙げられ、好ましくは（メタ）アクリレート基を有する２−ｔ−ブチル−６−（３−ｔ−ブチル−２−ヒドロキシ−５−メチルベンジル）−４−メチルフェニルアクリレート、２−［１−（２−ヒドロキシ−３，５−ジ−ｔ−ペンチルフェニル）エチル］−４，６−ジ−ｔ−ペンチルフェニルアクリレートの等が挙げられる。
【００６９】
ヒンダードアミン系化合物の例としては、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケート、ビス（２，２，６，６−テトラメチルー４−ピペリジル）セバケート、１−［２−〔３−（３，５−ジ−ｔ−ブチル−ヒドロキシフェニル）プロピオニルオキシ〕エチル］−４−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕−２，２，６，６−テトラメチルピペリジン、４−ベンゾイルオキシ−２，２，６，６−テトラメチルピペリジン、８−アセチル−３−ドデシル−７，７，９，９−テトラメチル−１，３，８−トリアザスピロ［４．５］デカン−２，４−ジオン等が挙げられる。
【００７０】
その他の重合防止剤としてはハイドロキノン、ｐ−メトキシフェノール、ジ−ｔ−ブチル−ｐ−クレゾール、ピロガロール、ｔ−ブチルカテコール、ベンゾキノン、４，４′−チオビス（３−メチル−６−ｔ−ブチルフェノール）、２，２′−メチレンビス（４−メチル−６−ｔ−ブチルフェノール）、Ｎ−ニトロソフェニルヒドロキシルアミン第一セリウム塩、２，２，６，６，−テトラメチルピペリジン誘導体等のヒンダードアミン類等があげられる。
【００７１】
重合防止剤の添加量は、上記組成物の全固形分の質量に対して、約０．０１％〜約５％が好ましい。また必要に応じて、酸素による重合阻害を防止するためにベヘン酸やベヘン酸アミドのような高級脂肪酸誘導体等を添加したり、塗布後の乾燥の過程で感光性層の表面に偏在させてもよい。高級脂肪酸誘導体の添加量は、全組成物の約０．５％〜約１０％が好ましい。
【００７２】
本発明の感光性平版印刷版材料の光重合性感光層の塗布組成物には、上記した成分の他に、着色剤も使用することができ、着色剤としては、市販のものを含め従来公知のものが好適に使用できる。例えば、改訂新版「顔料便覧」，日本顔料技術協会編（誠文堂新光社）、カラーインデックス便覧等に述べられているものが挙げられる。
【００７３】
顔料の種類としては、黒色顔料、黄色顔料、赤色顔料、褐色顔料、紫色顔料、青色顔料、緑色顔料、蛍光顔料、金属粉顔料等が挙げられる。具体的には、無機顔料（二酸化チタン、カーボンブラック、グラファイト、酸化亜鉛、プルシアンブルー、硫化カドミウム、酸化鉄、ならびに鉛、亜鉛、バリウム及びカルシウムのクロム酸塩等）及び有機顔料（アゾ系、チオインジゴ系、アントラキノン系、アントアンスロン系、トリフェンジオキサジン系の顔料、バット染料顔料、フタロシアニン顔料及びその誘導体、キナクリドン顔料等）が挙げられる。
【００７４】
これらの中でも、使用する露光レーザーに対応した分光増感色素の吸収波長域に実質的に吸収を持たない顔料を選択して使用することが好ましく、この場合、使用するレーザー波長での積分球を用いた顔料の反射吸収が０．０５以下であることが好ましい。又、顔料の添加量としては、上記組成物の固形分に対し０．１〜１０質量％が好ましく、より好ましくは０．２〜５質量％である。
【００７５】
また、支持体への接着性を向上させるために可塑剤を含有することができる。可塑剤としては、ジメチルフタレート、ジエチルフタレート、ジブチルフタレート、ジヘプチルフタレート、ジ−２−エチルヘキシルフタレート、ジ−ｎ−オクチルフタレート、ジドデシルフタレート、ジイソデシルフタレート、ブチルベンジルフタレート、ジイソノニルフタレート、エチルフタリルエチルグリコール、ジメチルイソフタレート、トリエチレングリコールジカプリレート、ジメチルグリコールフタレート、トリクレジルホスフェート、ジオクチルアジペート、ジブチルセバケート、トリアセチルグリセリンなどを挙げることができる。可塑剤の添加量は、上記塗布組成物の全固形分に対し好ましくは約０〜３質量％であり、より好ましくは０．１〜２質量％である。
【００７６】
また、上記塗布組成物は、本発明の性能を損わない範囲で、界面活性剤を塗布性改良剤として含有することができる。その中でも好ましいのはフッ素系界面活性剤である。
【００７７】
また、硬化皮膜の物性を改良するために、無機充填剤やジオクチルフタレート、ジメチルフタレート、トリクレジルホスフェート等の可塑剤等の添加剤を加えてもよい。これらの添加量は上記塗布組成物の全固形分の１０％以下が好ましい。
【００７８】
本発明の感光性平版印刷版材料の光重合性感光層の塗布組成物を調製する際に使用する溶剤としては、例えば、アルコール類：ｓｅｃ−ブタノール、イソブタノール、ｎ−ヘキサノール、ベンジルアルコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、１，５−ペンタンジオール等；エーテル類：プロピレングリコールモノブチルエーテル、ジプロピレングリコールモノメチルエーテル、トリプロピレングリコールモノメチルエーテル等；ケトン類、アルデヒド類：ジアセトンアルコール、シクロヘキサノン、メチルシクロヘキサノン等；エステル類：乳酸エチル、乳酸ブチル、シュウ酸ジエチル、安息香酸メチル等；が好ましく挙げられる。
【００７９】
調製された塗布組成物（感光層塗布液）は、従来公知の方法で支持体上に塗布し、乾燥し、感光性平版印刷版材料を作製することができる。塗布液の塗布方法としては、例えばエアドクタコータ法、ブレードコータ法、ワイヤバー法、ナイフコータ法、ディップコータ法、リバースロールコータ法、グラビヤコータ法、キャストコーティング法、カーテンコータ法及び押し出しコータ法等を挙げることができる。
【００８０】
感光層の乾燥温度は、６０〜１６０℃の範囲が好ましく、より好ましくは８０〜１４０℃、特に好ましくは９０〜１２０℃の範囲である。６０℃よりも低いと十分な耐刷性を得ることができない。又１６０℃よりも高過ぎるとマランゴニーを生じてしまうばかりか、非画線部のかぶりを生じてしまう。
【００８１】
本発明の感光性平版印刷版材料の光重合性感光層の上側には、保護層を設けることが好ましい。該保護層（酸素遮断層）は、後述する現像液（一般にはアルカリ水溶液）への溶解性が高いことが好ましい。
【００８２】
該保護層を構成する素材として好ましくは、ポリビニルアルコール、ポリサッカライド、ポリビニルピロリドン、ポリエチレングリコール、ゼラチン、膠、カゼイン、ヒドロキシエチルセルロース、カルボキシメチルセルロース、メチルセルロース、ヒドロキシエチル澱粉、アラビアゴム、サクローズオクタアセテート、アルギン酸アンモニウム、アルギン酸ナトリウム、ポリビニルアミン、ポリエチレンオキシド、ポリスチレンスルホン酸、ポリアクリル酸、水溶性ポリアミド等が挙げられる。これらの化合物を単独又は２種以上併用し保護層塗布組成物とし用いることができる。特に好ましい化合物としてはポリビニルアルコールが挙げられる。
【００８３】
保護層塗布組成物を調製するには、上記の素材を適当な溶剤に溶解して塗布液とすることができ、この塗布液を本発明に係る光重合性感光層上に塗布し、乾燥して保護層を形成することができる。保護層の厚みは０．１〜５．０μｍが好ましく、特に好ましくは０．５〜３．０μｍである。保護層には、更に必要に応じて界面活性剤、マット剤等を含有することができる。
【００８４】
保護層の塗布方法としても、上記感光層の塗布において挙げた公知の塗布方法を好適に用いることができる。保護層の乾燥温度は、感光層の乾燥温度よりも低い方が好ましく、好ましくは感光層乾燥温度との差が１０℃以上、より好ましくは２０℃以上であり、上限はせいぜい５０℃程度である。
【００８５】
また、保護層の乾燥温度が、感光層が含有するバインダーのガラス転移温度（Ｔｇ）より低いことが好ましい。保護層の乾燥温度と、感光層が含有するバインダーのガラス転移温度（Ｔｇ）の差は２０℃以上であることが好ましく、より好ましくは４０℃以上であり、上限はせいぜい６０℃程度である。
【００８６】
本発明の感光性平版印刷版材料に用いることができる支持体は、アルミニウム板が好ましく使用され、この場合、純アルミニウム板及びアルミニウム合金板等であってもかまわない。
【００８７】
支持体のアルミニウム合金としては、種々のものが使用でき、例えば、珪素、銅、マンガン、マグネシウム、クロム、亜鉛、鉛、ビスマス、ニッケル、チタン、ナトリウム、鉄等の金属とアルミニウムの合金が用いられ、各種圧延方法により製造されたアルミニウム板が使用できる。また、近年普及しつつあるスクラップ材およびリサイクル材などの再生アルミニウム地金を圧延した再生アルミニウム板も使用できる。
【００８８】
本発明の感光性平版印刷版材料及び本発明の画像形成方法に用いることができる支持体は、粗面化（砂目立て処理）するに先立って表面の圧延油を除去するために脱脂処理を施すことが好ましい。脱脂処理としては、トリクレン、シンナー等の溶剤を用いる脱脂処理、ケシロン、トリエタノール等のエマルジョンを用いたエマルジョン脱脂処理等が用いられる。又、脱脂処理には、苛性ソーダ等のアルカリの水溶液を用いることもできる。脱脂処理に苛性ソーダ等のアルカリ水溶液を用いた場合、上記脱脂処理のみでは除去できない汚れや酸化皮膜も除去することができる。脱脂処理に苛性ソーダ等のアルカリ水溶液を用いた場合、支持体の表面にはスマットが生成するので、この場合には、燐酸、硝酸、硫酸、クロム酸等の酸、或いはそれらの混酸に浸漬しデスマット処理を施すことが好ましい。
【００８９】
粗面化の方法としては、例えば、機械的方法、電解によりエッチングする方法が挙げられる。本発明の一つの形態では、粗面化方法は特に限定されないが、表面粗さＲａが０．４〜０．８μｍである。また、本発明の一つの形態では、塩酸を主体とする酸性電解液中で交流電解処理により粗面化を行う。
【００９０】
機械的粗面化法は特に限定されるものではないが、ブラシ研磨法、ホーニング研磨法が好ましい。ブラシ研磨法による粗面化は、例えば、直径０．２〜０．８ｍｍのブラシ毛を使用した回転ブラシを回転し、支持体表面に、例えば、粒径１０〜１００μｍの火山灰の粒子を水に均一に分散させたスラリーを供給しながら、ブラシを押し付けて行うことができる。ホーニング研磨による粗面化は、例えば、粒径１０〜１００μｍの火山灰の粒子を水に均一に分散させ、ノズルより圧力をかけ射出し、支持体表面に斜めから衝突させて粗面化を行うことができる。又、例えば、支持体表面に、粒径１０〜１００μｍの研磨剤粒子を、１００〜２００μｍの間隔で、２．５×１０^３〜１０×１０^３個／ｃｍ^２の密度で存在するように塗布したシートを張り合わせ、圧力をかけてシートの粗面パターンを転写することにより粗面化を行うこともできる。
【００９１】
上記の機械的粗面化法で粗面化した後、支持体の表面に食い込んだ研磨剤、形成されたアルミニウム屑等を取り除くため、酸又はアルカリの水溶液に浸漬することが好ましい（以降、デスマット処理と呼ぶことがある）。酸としては、例えば、硫酸、過硫酸、弗酸、燐酸、硝酸、塩酸等が用いられ、塩基としては、例えば水酸化ナトリウム、水酸化カリウム等が用いられる。これらの中でも、水酸化ナトリウム等のアルカリ水溶液を用いるのが好ましい。表面のアルミニウムの溶解量としては、０．５〜５ｇ／ｍ^２が好ましい。アルカリ水溶液で浸漬処理を行った後、燐酸、硝酸、硫酸、クロム酸等の酸或いはそれらの混酸に浸漬し中和処理を施すことが好ましい。
【００９２】
電気化学的粗面化法も特に限定されるものではないが、酸性電解液中で電気化学的に交流電流で粗面化を行う方法が好ましい。酸性電解液は、電気化学的粗面化法に通常用いられる酸性電解液を使用することができるが、塩酸系または硝酸系電解液を用いるのが好ましい。電気化学的粗面化方法については、例えば、特公昭４８−２８１２３号、英国特許第８９６，５６３号、特開昭５３−６７５０７号に記載されている方法を用いることができる。この粗面化法は、一般には、１〜５０ボルトの範囲の電圧を印加することによって行うことができるが、１０〜３０ボルトの範囲から選ぶのが好ましい。電流密度は、１０〜２００Ａ／ｄｍ^２の範囲を用いることができるが、２０〜１５０Ａ／ｄｍ^２の範囲から選ぶのが好ましい。電気量は、１００〜５０００ｃ／ｄｍ^２の範囲を用いることができるが、１００〜２５００ｃ／ｄｍ^２の範囲から選ぶのが好ましい。この粗面化法を行う温度は、１０〜５０℃の範囲を用いることができるが、１５〜４５℃の範囲から選ぶのが好ましい。
【００９３】
電解液として硝酸系電解液を用いて電気化学的粗面化を行う場合、一般には、１〜５０ボルトの範囲の電圧を印加することによって行うことができるが、１０〜３０ボルトの範囲から選ぶのが好ましい。電流密度は、１０〜２００Ａ／ｄｍ^２の範囲を用いることができるが、２０〜１００Ａ／ｄｍ^２の範囲から選ぶのが好ましい。電気量は、１００〜５０００ｃ／ｄｍ^２の範囲を用いることができるが、１００〜２５００ｃ／ｄｍ^２の範囲から選ぶのが好ましい。電気化学的粗面化法を行う温度は、１０〜５０℃の範囲を用いることができるが、１５〜４５℃の範囲から選ぶのが好ましい。電解液における硝酸濃度は０．１〜５質量％が好ましい。電解液には、必要に応じて、硝酸塩、塩化物、アミン類、アルデヒド類、燐酸、クロム酸、ホウ酸、酢酸、しゅう酸等を加えることができる。
【００９４】
電解液として塩酸系電解液を用いる場合、一般には、１〜５０ボルトの範囲の電圧を印加することによって行うことができるが、２〜３０ボルトの範囲から選ぶのが好ましい。電流密度は、１０〜２００Ａ／ｄｍ^２の範囲を用いることができるが、２０〜１５０Ａ／ｄｍ^２の範囲から選ぶのが好ましい。電気量は、１００〜５０００ｃ／ｄｍ^２の範囲を用いることができるが、好ましくは１００〜２５００ｃ／ｄｍ^２、更には２００〜２５００ｃ／ｄｍ^２の範囲から選ぶのがより好ましい。電気化学的粗面化法を行う温度は、１０〜５０℃の範囲を用いることができるが、１５〜４５℃の範囲から選ぶのが好ましい。電解液における塩酸濃度は０．１〜５質量％が好ましい。電解液には、必要に応じて、硝酸塩、塩化物、アミン類、アルデヒド類、燐酸、クロム酸、ホウ酸、酢酸、しゅう酸等を加えることができる。
【００９５】
上記の電気化学的粗面化法で粗面化した後、表面のアルミニウム屑等を取り除くため、酸又はアルカリの水溶液に浸漬することが好ましい（デスマット処理）。酸としては、例えば、硫酸、過硫酸、弗酸、燐酸、硝酸、塩酸等が用いられ、塩基としては、例えば、水酸化ナトリウム、水酸化カリウム等が用いられる。これらの中でもアルカリの水溶液を用いるのが好ましい。表面のアルミニウムの溶解量としては、０．５〜５ｇ／ｍ^２が好ましい。又、アルカリの水溶液で浸漬処理を行った後、燐酸、硝酸、硫酸、クロム酸等の酸或いはそれらの混酸に浸漬し中和処理を施すことが好ましい。
【００９６】
機械的粗面化法、電気化学的粗面化法はそれぞれ単独で用いて粗面化してもよいし、又、機械的粗面化処理法に次いで電気化学的粗面化法を行って粗面化してもよい。
【００９７】
本発明の平均間隔または平均径が３０〜１５０ｎｍで構成される凹凸部が５０〜１１００個／μｍ^２である微細粗面は、機械的粗面化法、硝酸系電解液による交流電解粗面化法では形成されない。その場合は、陽極酸化処理後に封孔処理を行う必要がある。
【００９８】
一方、塩酸系電解液による交流電解粗面化法では本発明の微細粗面が形成されるが、デスマット処理により表面のアルミニウム屑と同時に微細粗面も溶解してしまう場合がある。その場合は、陽極酸化処理後に封孔処理を行う必要がある。またデスマット処理による表面のアルミニウム溶解量を０．５〜１．５ｇ／ｍ^２にすれば微細粗面は溶解されずに維持される。
【００９９】
粗面化処理の次には、陽極酸化処理を行う。本発明において用いることができる陽極酸化処理の方法には特に制限はなく、公知の方法を用いることができる。陽極酸化処理を行うことにより、支持体上には酸化皮膜が形成される。該陽極酸化処理には、硫酸及び／又は燐酸等を１０〜５０％の濃度で含む水溶液を電解液として、電流密度１〜５０Ａ／ｄｍ^２で電解する方法が好ましく用いられるが、他に、米国特許第１，４１２，７６８号に記載されている硫酸中で高電流密度で電解する方法や、同３，５１１，６６１号公報に記載されている燐酸を用いて電解する方法、クロム酸、シュウ酸、マロン酸等を一種又は二種以上含む溶液を用いる方法等が挙げられる。形成された陽極酸化被覆量は、１〜５０ｍｇ／ｄｍ^２が適当であり、好ましくは１０〜４０ｍｇ／ｄｍ^２である。陽極酸化被覆量は、例えばアルミニウム板を燐酸クロム酸溶液（燐酸８５％液：３５ｍｌ、酸化クロム（ＩＶ）：２０ｇを１Ｌの水に溶解して作製）に浸積し、酸化被膜を溶解し、板の被覆溶解前後の質量変化測定等から求められる。
【０１００】
陽極酸化処理された支持体は、必要に応じ封孔処理を施してもよい。これら封孔処理は、熱水処理、沸騰水処理、水蒸気処理、珪酸ソーダ処理、重クロム酸塩水溶液処理、亜硝酸塩処理、酢酸アンモニウム処理等公知の方法を用いて行うことができる。
【０１０１】
機械的粗面化法、硝酸系電解液による交流電解粗面化法では本発明の平均間隔または平均径が３０〜１５０ｎｍで構成される凹凸部が５０〜１１００個／μｍ^２である微細粗面は形成されないため、封孔処理により形成する必要がある。その場合は、熱水処理または酢酸アンモニウム処理が好ましい。熱水処理の場合は、温度は７０〜９７℃、処理時間５〜１８０秒の間で条件を組み合わせ所望の微細粗面を得ることが出来る。また、酢酸アンモニウムでｐＨを７〜９．５に調整することにより、より短時間で所望の微細粗面を得ることが出来る。
【０１０２】
一方、塩酸系電解液による交流電解粗面化法では本発明の微細粗面が形成されるが、デスマット処理により微細粗面も溶解してしまった場合は、上記熱水処理または酢酸アンモニウム処理で再形成することが出来る。また、デスマット処理条件と熱水処理または酢酸アンモニウム処理の組み合わせで微細構造を形成しても良い。
【０１０３】
更に、本発明では、これらの処理を行った後に、親水化処理を施すことが好ましい。親水化処理は特に限定されないが、水溶性の樹脂、たとえばポリビニルホスホン酸、スルホン酸基を側鎖に有する重合体および共重合体、ポリアクリル酸、水溶性金属塩（例えばホウ酸亜鉛）もしくは、黄色染料、アミン塩等を下塗りしたものが使用できる。更に、特開平５−３０４３５８号公報に開示されているようなラジカルによって付加反応を起し得る官能基を共有結合させたゾル−ゲル処理基板も用いられる。好適なのは、ポリビニルホスホン酸で支持体表面を親水化処理を行うことである。処理としては、塗布式、スプレー式、ディップ式等限定されないが、設備を安価にするにはディップ式が好適である。ディップ式の場合には、ポリビニルホスホン酸を０．０５〜３％の水溶液で処理することが好ましい。処理温度は２０〜９０℃、処理時間は１０〜１８０秒が好ましい。処理後、過剰に積層したポリビニルホスホン酸を除去するため、スキージ処理または水洗処理を行うことが好ましい。更に乾燥処理を行うことが好ましい。乾燥温度としては、２０〜９５℃が好ましい。
【０１０４】
本発明では、３５０ｎｍから４５０ｎｍ域でのレーザー光源で露光を行う。３５０〜４５０ｎｍの波長の入手可能なレーザー光源としては以下のものを利用することができる。ガスレーザーとして、Ａｒイオンレーザー（３６４ｎｍ、３５１ｎｍ）、Ｋｒイオンレーザー（３５６ｎｍ，３５１ｎｍ）、Ｈｅ−Ｃｄレーザー（４４１ｎｍ）、固体レーザーとして、Ｎｄ：ＹＡＧ（ＹＶＯ４）とＳＨＧ結晶×２回の組合わせ（３５５ｎｍ）、Ｃｒ：ＬｉＳＡＦとＳＨＧ結晶の組合わせ（４３０ｎｍ）、半導体レーザー系として、ＫＮｂＯ_３、リング共振器（４３０ｎｍ）、導波型波長変換素子とＡｌＧａＡｓ、ＩｎＧａＡｓ半導体の組合わせ（３８０ｎｍ〜４５０ｎｍ）、導波型波長変換素子とＡｌＧａＩｎＰ、ＡｌＧａＡｓ半導体の組合わせ（３００ｎｍ〜３５０ｎｍ）、ＡｌＧａＩｎＮ（３５０ｎｍ〜４５０ｎｍ）、その他にパルスレーザーとしてＮ_２レーザー（３３７ｎｍ、パルス０．１〜１０ｍＪ）、ＸｅＦ（３５１ｎｍ、パルス１０〜２５０ｍＪ）等が挙げられる。特にこの中でＡｌＧａＩｎＮ半導体レーザー（市販ＩｎＧａＮ系半導体レーザー４００〜４１０ｎｍ）が波長特性、コストの面で好適である。
【０１０５】
レーザーの走査方法としては、円筒外面走査、円筒内面走査、平面走査などがある。円筒外面走査では、記録材料を外面に巻き付けたドラムを回転させながらレーザー露光を行い、ドラムの回転を主走査としレーザー光の移動を副走査とする。円筒内面走査では、ドラムの内面に記録材料を固定し、レーザービームを内側から照射し、光学系の一部又は全部を回転させることにより円周方向に主走査を行い、光学系の一部又は全部をドラムの軸に平行に直線移動させることにより軸方向に副走査を行う。平面走査では、ポリゴンミラーやガルバノミラーとｆθレンズ等を組み合わせてレーザー光の主走査を行い、記録媒体の移動により副走査を行う。円筒外面走査及び円筒内面走査の方が光学系の精度を高め易く、高密度記録には適している。
【０１０６】
本発明では、画像露光後、画像形成反応の促進、感度や耐刷性の向上のため加熱処理が施されることが好ましい。加熱処理の方法は特に限定されないが画像形成面への非接触方式が好ましく、通常の恒温槽、熱風式乾燥機および加熱処理部を装着した市販の自動現像機を使用できる。加熱温度は版面温度で１００〜１３０℃で行うことが好ましい。温度が高すぎると非画像部のかぶりが生じる等の問題があり、また温度が低すぎると感度、耐刷性が不十分等の問題が生じる。加熱時間は５〜６０秒で行うことが好ましい。加熱時間が長すぎると非画像部のかぶりが生じる等の問題があり、また加熱時間が短すぎると感度、耐刷性が不十分等の問題が生じる。露光終了から加熱処理までの時間は３００秒以内が好ましい。３００秒を越えると感度、耐刷性が不十分等の問題が生じる。
【０１０７】
本発明の処理方法に用いられる現像液および補充液の主成分は、珪酸、燐酸、炭酸、硼酸、フェノール類、糖類、オキシム類およびフッ素化アルコール類から選ばれる少なくとも一種の化合物を含有することが好ましい。ｐＨは８．５より高く１３．０未満の範囲であるアルカリ性水溶液であることが好ましい。さらに好ましくはｐＨ８．５〜１２である。これらのうちフェノール類、糖類、オキシム類およびフッ素化アルコール類の如き弱酸性物質としては、解離指数（ｐＫａ）が１０．０〜１３．２のものが好ましい。このような酸としては、ＰｅｒｇａｍｏｎＰｒｅｓｓ社発行のＩＯＮＩＳＡＴＩＯＮ ＣＯＮＳＴＡＮＴＳ ＯＦ ＯＲＧＡＮＩＣ ＡＣＩＤＳ ＩＮＡＱＵＥＯＵＳ ＳＯＬＵＴＩＯＮなどに記載されているものから選ばれ、具体的には、サリチル酸（同１３．０）、３−ヒドロキシ−２−ナフトエ酸（同１２．８４）、カテコール（同１２．６）、没食子酸（同１２．４）、スルホサリチル酸（同１１．７）、３，４−ジヒドロキシスルホン酸（同１２．２）、３，４−ジヒドロキシ安息香酸（同１１．９４）、１，２，４−トリヒドロキシベンゼン（同１１．８２）、ハイドロキノン（同１１．５６）、ピロガロール（同１１．３４）、ｏ−クレゾール（同１０．３３）、レゾルソノール（同１１．２７）、ｐ−クレゾール（同１０．２７）、ｍ−クレゾール（同１０．０９）などのフェノール性水酸基を有するフェノール類が挙げられる。
【０１０８】
糖類としてはアルカリ中でも安定な非還元糖が好ましく用いられる。かかる非還元糖とは、遊離のアルデヒド基やケトン基を持たず、還元性を示さない糖類であり、還元基同士の結合したトレハロース型少糖類、糖類の還元基と非糖類が結合した配糖体および糖類に水素添加して還元した糖アルコールに分類され、何れも本発明に好適に用いられる。トレハロース型少糖類には、サッカロースやトレハロースがあり、配糖体としては、アルキル配糖体、フェノール配糖体、カラシ油配糖体などが挙げられる。また糖アルコールとしてはＤ，Ｌ−アラビット、リビット、キシリット、Ｄ，Ｌ−ソルビット、Ｄ，Ｌ−マンニット、Ｄ，Ｌ−イジット、Ｄ，Ｌ−タリット、ズリシットおよびアロズルシットなどが挙げられる。更に二糖類の水素添加で得られるマルチトールおよびオリゴ糖の水素添加で得られる還元体（還元水あめ）が好適に用いられる。更には、２−ブタノンオキシム（同１２．４５）、アセトキシム（同１２．４２）、１．２−シクロヘプタンジオンオキシム（同１２．３）、２−ヒドロキシベンズアルデヒドオキシム（同１２．１０）、ジメチルグリオキシム（同１１．９）、エタンジアミドジオキシム（同１１．３７）、アセトフェノンオキシム（同１１．３５）などのオキシム類、例えば２，２，３，３−テトラフルオロプロパノール−１（同１２．７４）、トリフルオロエタノール（同１２．３７）、トリクロロエタノール（同１２．２４）などのフッ素化アルコール類が挙げられる。他にも、ピリジン−２−アルデヒド（同１２．６８）、ピリジン−４−アルデヒド（同１２．０５）などのアルデヒド類、アデノシン（同１２．５６）、イノシン（同１２．５）、グアニン（同１２．３）、シトシン（同１２．２）、ヒポキサンチン（同１２．１）、キサンチン（同１１．９）などの核酸関連物質、他に、ジエチルアミノメチルスルホン酸（同１２．３２）、１−アミノ−３，３，３−トリフルオロ安息香酸（同１２．２９）、イソプロピリデンジスルホン酸（同１２．１０）、１，１−エチリデンジホスホン酸（同１１．５４）、１，１−エチリデンジスルホン酸１−ヒドロキシ（同１１．５２）、ベンズイミダゾール（同１２．８６）、チオベンズアミド（同１２．８）、ピコリンチオアミド（同１２．５５）、バルビツル酸（同１２．５）などの弱酸が挙げられる。これらの酸性物質は単独でも、また二種以上を組み合わせて用いてもよい。これらの酸性物質の中で好ましいのは、珪酸、燐酸、炭酸、スルホサリチル酸、サリチル酸及び非還元糖の糖アルコールとサッカロースであり、特に珪酸、Ｄ−ソルビット、サッカロース、還元水あめが適度なｐＨ領域に緩衝作用があることと、低価格であることで好ましい。
【０１０９】
これらの酸性物質の現像液中に占める割合は０．１〜３０質量％が好ましく、更に好ましくは、１〜２０質量％である。この範囲以下では十分な緩衝作用が得られず、またこの範囲以上の濃度では、高濃縮化し難く、また原価アップの問題が出てくる。これらの酸に組み合わせる塩基としては、水酸化ナトリウム、同アンモニウム、同カリウムおよび同リチウムが好適に用いられる。これらのアルカリ剤は単独もしくは二種以上を組み合わせて用いられる。現像液のｐＨが８．５以下の場合、このような現像液で現像可能な感光性平版印刷版から得られる印刷版の画像部は物理的に脆弱であり、印刷中の摩耗が早く十分な耐刷力が得られない。また、その画像部は化学的にも弱く、印刷中にインキ洗浄溶剤やプレートクリーナー等で拭いた部分の画像がダメージを受け、その結果、十分な耐薬品性が得られない。ｐＨが１３．０を越える様な高ｐＨの現像液は皮膚や粘膜へ付着した場合の刺激性が強く、取扱いには十分な注意を必要とし好ましくない。
【０１１０】
その他として、例えば、珪酸カリウム、珪酸ナトリウム、珪酸リチウム、珪酸アンモニウム、メタ珪酸カリウム、メタ珪酸ナトリウム、メタ珪酸リチウム、メタ珪酸アンモニウム、燐酸三カリウム、燐酸三ナトリウム、燐酸三リチウム、燐酸三アンモニウム、燐酸二カリウム、燐酸二ナトリウム、燐酸二リチウム、燐酸二アンモニウム、炭酸カリウム、炭酸ナトリウム、炭酸リチウム、炭酸アンモニウム、炭酸水素カリウム、炭酸水素ナトリウム、炭酸水素リチウム、炭酸水素アンモニウム、硼酸カリウム、硼酸ナトリウム、硼酸リチウム、硼酸アンモニウム等があげられ、予め形成された塩の形で加えられてもよい。この場合も、水酸化ナトリウム、同アンモニウム、同カリウムおよび同リチウムをｐＨ調整に加えることができる。また、モノメチルアミン、ジメチルアミン、トリメチルアミン、モノエチルアミン、ジエチルアミン、トリエチルアミン、モノイソプロピルアミン、ジイソプロピルアミン、トリイソプロピルアミン、ｎ−ブチルアミン、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、モノイソプロパノールアミン、ジイソプロパノールアミン、エチレンイミン、エチレンジアミン、ピリジンなどの有機アルカリ剤も組み合わせて用いられる。もっとも好ましいものとして珪酸カリウム及び珪酸ナトリウムがあげられる。珪酸塩の濃度は、ＳｉＯ_２濃度換算で１．０〜３．０質量％が好ましい。また、ＳｉＯ_２とアルカリ金属Ｍのｍｏｌ比（ＳｉＯ_２／Ｍ）が、０．２５〜２の範囲であればなお好ましい。
【０１１１】
尚、本発明で言う現像液とは現像のスタート時に使用される未使用の液だけでなく、ＰＳ版の処理によって低下する液の活性度を補正するために補充液が補充され、活性度が保たれた液（いわゆるランニング液）を含む。補充液は従って、現像液より活性度（アルカリ濃度）が高い必要があるので補充液のｐＨは１３．０を超えていてもよい。
【０１１２】
本発明に用いられる現像液および補充液には、現像性の促進や現像カスの分散および印刷版画像部の親インキ性を高める目的で必要に応じて種々界面活性剤や有機溶剤を添加できる。好ましい界面活性剤としては、アニオン系、カチオン系、ノニオン系および両性界面活性剤が挙げられる。界面活性剤の好ましい例としては、ポリオキシエチレンアルキルエーテル類、ポリオキシエチレンアリールエーテル、エステルポリオキシエチレンアルキルフェニルエーテル類、ポリオキシエチレンナフチルエーテル、ポリオキシエチレンポリスチリルフェニルエーテル類、ポリオキシエチレンポリオキシプロピレンアルキルエーテル類、グリセリン脂肪酸部分エステル類、ソルビタン脂肪酸部分エステル類、ペンタエリスリトール脂肪酸部分エステル類、プロピレングリコールモノ脂肪酸エステル類、しょ糖脂肪酸部分エステル類、ポリオキシエチレンソルビタン脂肪酸部分エステル類、ポリオキシエチレンソルビトール脂肪酸部分エステル類、ポリエチレングリコール脂肪酸エステル類、ポリグリセリン脂肪酸部分エステル類、ポリオキシエチレン化ひまし油類、ポリオキシエチレングリセリン脂肪酸部分エステル類、ポリオキシエチレン−ポリオキシプロピレンブロック共重合体、エチレンジアミンのポリオキシエチレン−ポリオキシプロピレンブロック共重合体付加物、脂肪酸ジエタノールアミド類、Ｎ，Ｎ−ビス−２−ヒドロキシアルキルアミン類、ポリオキシエチレンアルキルアミン、トリエタノールアミン脂肪酸エステル、トリアルキルアミンオキシドなどの非イオン性界面活性剤、脂肪酸塩類、アビエチン酸塩類、ヒドロキシアルカンスルホン酸塩類、アルカンスルホン酸塩類、ジアルキルスルホ琥珀酸エステル塩類、直鎖アルキルベンゼンスルホン酸塩類、分岐鎖アルキルベンゼンスルホン酸塩類、アルキルナフタレンスルホン酸塩類、ポリオキシエチレンアリールエーテルカルボン酸、ポリオキシエチレンナフチルエーテル硫酸エステル塩、アルキルジフェニルエーテルスルホン酸塩類、アルキルフェノキシポリオキシエチレンプロピルスルホン酸塩類、ポリオキシエチレンアルキルスルホフェニルエーテル塩類、ポリオキシエチレンアリールルエーテル硫酸エステル塩、Ｎ−メチル−Ｎ−オレイルタウリンナトリウム塩、Ｎ−アルキルスルホ琥珀酸モノアミド二ナトリウム塩、石油スルホン酸塩類、硫酸化牛脂油、脂肪酸アルキルエステルの硫酸エステル塩類、アルキル硫酸エステル塩類、ポリオキシエチレンアルキルエーテル硫酸エステル塩類、脂肪酸モノグリセリド硫酸エステル塩類、ポリオキシエチレンアルキルフェニルエーテル硫酸エステル塩類、ポリオキシエチレンスチリルフェニルエーテル硫酸エステル塩類、アルキルリン酸エステル塩類、ポリオキシエチレンアルキルエーテルリン酸エステル塩類、ポリオキシエチレンアルキルフェニルエーテルリン酸エステル塩類、スチレン／無水マレイン酸共重合物の部分鹸化物類、オレフィン／無水マレイン酸共重合物の部分鹸化物類、ナフタレンスルホン酸塩ホルマリン縮合物類などのアニオン界面活性剤、アルキルアミン塩類、テトラブチルアンモニウムブロミド等の第四級アンモニウム塩類、ポリオキシエチレンアルキルアミン塩類、ポリエチレンポリアミン誘導体などのカチオン性界面活性剤、カルボキシベタイン類、アミノカルボン酸類、スルホベタイン類、アミノ硫酸エステル類、イミダゾリン類などの両性界面活性剤が挙げられる。以上挙げた界面活性剤の中でポリオキシエチレンとあるものは、ポリオキシメチレン、ポリオキシプロピレン、ポリオキシブチレンなどのポリオキシアルキレンに読み替えることもでき、それらの界面活性剤もまた包含される。更に好ましい界面活性剤は分子内にパーフルオロアルキル基を含有するフッ素系の界面活性剤である。かかるフッ素系界面活性剤としては、パーフルオロアルキルカルボン酸塩、パーフルオロアルキルスルホン酸塩、パーフルオロアルキルリン酸エステルなどのアニオン型、パーフルオロアルキルベタインなどの両性型、パーフルオロアルキルトリメチルアンモニウム塩などのカチオン型およびパーフルオロアルキルアミンオキサイド、パーフルオロアルキルエチレンオキシド付加物、パーフルオロアルキル基および親水性基含有オリゴマー、パーフルオロアルキル基および親油性基含有オリゴマー、パーフルオロアルキル基、親水性基および親油性基含有オリゴマー、パーフルオロアルキル基および親油性基含有ウレタンなどの非イオン型が挙げられる。上記の界面活性剤は、単独もしくは２種以上を組み合わせて使用することができ、現像液中に０．００１〜１０質量％、より好ましくは０．０１〜５質量％の範囲で添加される。
【０１１３】
本発明に用いられる現像液および補充液には、好ましくは種々現像安定化剤が用いられる。それらの好ましい例として、特開平６−２８２０７９号公報記載の糖アルコールのポリエチレングリコール付加物、テトラブチルアンモニウムヒドロキシドなどのテトラアルキルアンモニウム塩、テトラブチルホスホニウムブロマイドなどのホスホニウム塩およびジフェニルヨードニウムクロライドなどのヨードニウム塩が好ましい例として挙げられる。更には、特開昭５０−５１３２４号公報記載のアニオン界面活性剤または両性界面活性剤、また特開昭５５−９５９４６号公報記載の水溶性カチオニックポリマー、特開昭５６−１４２５２８号公報に記載されている水溶性の両性高分子電解質がある。更に、特開昭５９−８４２４１号公報のアルキレングリコールが付加された有機ホウ素化合物、特開昭６０−１１１２４６号公報記載のポリオキシエチレン・ポリオキシプロピレンブロック重合型の水溶性界面活性剤、特開昭６０−１２９７５０号公報のポリオキシエチレン・ポリオキシプロピレンを置換したアルキレンジアミン化合物、特開昭６１−２１５５５４号公報記載の質量平均分子量３００以上のポリエチレングリコール、特開昭６３−１７５８５８号公報のカチオン性基を有する含フッ素界面活性剤、特開平２−３９１５７号公報の酸またはアルコールに４モル以上のエチレンオキシドを付加して得られる水溶性エチレンオキシド付加化合物と、水溶性ポリアルキレン化合物などが挙げられる。
【０１１４】
現像液および現像補充液には更に必要により有機溶剤が加えられる。かかる有機溶剤としては、水に対する溶解度が約１０質量％以下のものが適しており、好ましくは５質量％以下のものから選ばれる。例えば、１−フェニルエタノール、２−フェニルエタノール、３−フェニル−１−プロパノール、４−フェニル−１−ブタノール、４−フェニル−２−ブタノール、２−フェニル−１−ブタノール、２−フェノキシエタノール、２−ベンジルオキシエタノール、ｏ−メトキシベンジルアルコール、ｍ−メトキシベンジルアルコール、ｐ−メトキシベンジルアルコール、ベンジルアルコール、シクロヘキサノール、２−メチルシクロヘキサノール、３−メチルシクロヘキサノールおよび４−メチルシクロヘキサノール、Ｎ−フェニルエタノールアミンおよびＮ−フェニルジエタノールアミンなどを挙げることができる。有機溶剤の含有量は使用液の総質量に対して０．１〜５質量％であるが、実質的に含まれないことが好ましく、全く含まれないことが特に好ましい。ここで実質的に含まれないとは１質量％以下であることを示す。
【０１１５】
本発明に用いられる現像液および補充液には必要に応じて還元剤が加えられる。これは印刷版の汚れを防止するものであり、特に感光性ジアゾニウム塩化合物を含むネガ型感光性平版印刷版を現像する際に有効である。好ましい有機還元剤としては、チオサリチル酸、ハイドロキノン、メトール、メトキシキノン、レゾルシン、２−メチルレゾルシンなどのフェノール化合物、フェニレンジアミン、フェニルヒドラジンなどのアミン化合物が挙げられる。更に好ましい無機の還元剤としては、亜硫酸、亜硫酸水素酸、亜リン酸、亜リン酸水素酸、亜リン酸二水素酸、チオ硫酸および亜ジチオン酸などの無機酸のナトリウム塩、カリウム塩、アンモニウム塩などを挙げることができる。これらの還元剤のうち汚れ防止効果が特に優れているのは亜硫酸塩である。これらの還元剤は使用時の現像液に対して好ましくは、０．０５〜５質量％の範囲で含有される。
【０１１６】
本発明に用いられる現像液および補充液には必要に応じて更に有機カルボン酸を加えることもできる。好ましい有機カルボン酸は炭素原子数６〜２０の脂肪族カルボン酸および芳香族カルボン酸である。脂肪族カルボン酸の具体的な例としては、カプロン酸、エナンチル酸、カプリル酸、ラウリン酸、ミリスチン酸、パルミチン酸およびステアリン酸などがあり、特に好ましいのは炭素数８〜１２のアルカン酸である。また炭素鎖中に二重結合を有する不飽和脂肪酸でも、枝分かれした炭素鎖のものでもよい。芳香族カルボン酸としてはベンゼン環、ナフタレン環、アントラセン環などにカルボキシル基が置換された化合物で、具体的には、ｏ−クロロ安息香酸、ｐ−クロロ安息香酸、ｏ−ヒドロキシ安息香酸、ｐ−ヒドロキシ安息香酸、ｏ−アミノ安息香酸、ｐ−アミノ安息香酸、２，４−ジヒドロキシ安息香酸、２，５−ジヒドロキシ安息香酸、２，６−ジヒドロキシ安息香酸、２，３−ジヒドロキシ安息香酸、３，５−ジヒドロキシ安息香酸、没食子酸、１−ヒドロキシ−２−ナフトエ酸、３−ヒドロキシ−２−ナフトエ酸、２−ヒドロキシ−１−ナフトエ酸、１−ナフトエ酸、２−ナフトエ酸などがあるがヒドロキシナフトエ酸は特に有効である。上記脂肪族および芳香族カルボン酸は水溶性を高めるためにナトリウム塩やカリウム塩またはアンモニウム塩として用いるのが好ましい。本発明で用いる現像液の有機カルボン酸の含有量は格別な制限はないが、０．１質量％より低いと効果が十分でなく、また１０質量％以上ではそれ以上の効果の改善が計れないばかりか、別の添加剤を併用する時に溶解を妨げることがある。従って、好ましい添加量は使用時の現像液に対して０．１〜１０質量％であり、よりこのましくは０．５〜４質量％である。
【０１１７】
本発明に用いられる現像液および補充液には現像性能を高めるために前記の他に以下のような添加剤を加えることができる。例えば特開昭５８−７５１５２号公報記載のＮａＣｌ、ＫＣｌ、ＫＢｒ等の中性塩、特開昭５９−１２１３３６号公報記載の［Ｃｏ（ＮＨ_３）］_６Ｃｌ_３等の錯体、特開昭５６−１４２２５８号公報記載のビニルベンジルトリメチルアンモニウムクロライドとアクリル酸ナトリウムの共重合体等の両性高分子電解質、特開昭５９−７５２５５号公報記載のＳｉ、Ｔｉ等を含む有機金属界面活性剤、特開昭５９−８４２４１号公報記載の有機硼素化合物等が挙げられる。本発明に用いられる現像液および補充液には更に必要に応じて、防腐剤、着色剤、増粘剤、消泡剤および硬水軟化剤などを含有させることもできる。消泡剤としては例えば、特開平２−２４４１４３号公報記載の鉱物油、植物油、アルコール、界面活性剤、シリコーン等が挙げられる。硬水軟化剤としては例えば、ポリ燐酸およびそのナトリウム塩、カリウム塩およびアンモニウム塩、エチレンジアミンテトラ酢酸、ジエチレントリアミンペンタ酢酸、エチレンジアミンジコハク酸、メチルイミノジ酢酸、βアラニンジ酢酸、トリエチレンテトラミンヘキサ酢酸、ヒドロキシエチルエチレンジアミントリ酢酸、ニトリロトリ酢酸、１，２−ジアミノシクロヘキサンテトラ酢酸および１，３−ジアミノ−２−プロパノールテトラ酢酸などのアミノポリカルボン酸およびそれらのナトリウム塩、カリウム塩およびアンモニウム塩、アミノトリ（メチレンホスホン酸）、エチレンジアミンテトラ（メチレンホスホン酸）、ジエチレントリアミンペンタ（メチレンホスホン酸）、トリエチレンテトラミンヘキサ（メチレンホスホン酸）、ヒドロキシエチルエチレンジアミントリ（メチレンホスホン酸）および１−ヒドロキシエタン−１，１−ジホスホン酸やそれらのナトリウム塩、カリウム塩およびアンモニウム塩を挙げることができる。このような硬水軟化剤はそのキレート化力と使用される硬水の硬度および硬水の量によって最適値が変化するが、一般的な使用量を示せば、使用時の現像液に０．０１〜５質量％、より好ましくは０．０１〜０．５質量％の範囲である。この範囲より少ない添加量では所期の目的が十分に達成されず、添加量がこの範囲より多い場合は、色抜けなど、画像部への悪影響がでてくる。現像液および補充液の残余の成分は水である。得られた現像液の電導度は５〜５０ｍＳの範囲であることがより好ましい。
【０１１８】
本発明に用いられる現像液および補充液は使用時よりも水の含有量を少なくした濃縮液としておき、使用時に水で希釈するようにしておくことが運搬上有利である。この場合の濃縮度は各成分が分離や析出を起こさない程度が適当であるが、必要により可溶化剤を加えることが好ましい。かかる可溶化剤としては、特開平６−３２０８１号公報記載のトルエンスルホン酸、キシレンスルホン酸およびそれらのアルカリ金属塩等のいわゆるヒドロトロープ剤が好ましく用いられる。
【０１１９】
濃縮液の水の含有量をさらに減らし、固形状もしくはペースト状にすることもできる。この場合、一旦現像液にしてから蒸発乾固しても良いが、好ましくは複数の素材を混ぜ合わせる際に水を加えず、または少量の水を加える方法で素材を混ぜ合わせることで濃縮状態とする方法が好ましい。また、この現像液濃縮物は、特開昭５１−６１８３７号、特開平２−１０９０４２号、特開平２−１０９０４３号、特開平３−３９７３５号、特開平５−１４２７８６号、特開平６−２６６０６２号、特開平７−１３３４１号等に記載された従来よく知られた方法にて顆粒状、錠剤とすることができる。固形状もしくはペースト状の現像液濃縮物に含まれる素材は、通常の感光性平版印刷版の現像液に用いられる成分を使用することができるが、水で希釈してももとに戻らないものは含まない方が好ましい。たとえば、珪酸塩は水分が低くなると石化し水に溶けにくくなるので、珪酸塩の代わりに後述の炭酸塩、燐酸塩、有機酸塩等を含むことが好ましい。
【０１２０】
これらの現像液の濃縮液もしくは固形状もしくはペースト状の濃縮物は、素材種や素材配合比等の異なる複数のパートに分けても良い。これらの濃縮した現像液濃縮物は、現像前に水で所定の濃度に希釈した後現像に使用することが好ましい。またこの現像液濃縮液または濃縮物を現像補充液として用いる場合は、所定の濃度に水で希釈した後、使用中の現像液に投入することが最も好ましいが、所定の濃度より濃い濃度や、所定の濃度に希釈せずそのまま使用中の現像液に投入することも可能である。所定の濃度より濃い濃度や、所定の濃度に希釈せずそのままで現像液濃縮物を使用中の現像液に投入する際は、同じタイミングまたは別のタイミングで使用中の現像液に直接別途に水を添加しても良い。
【０１２１】
本発明に用いる自動現像機は、好ましくは現像浴に自動的に補充液を必要量補充する機構が付与されており、好ましくは一定量を超える現像液は、排出する機構が付与されており、好ましくは現像浴に自動的に水を必要量補充する機構が付与されており、好ましくは、通版を検知する機構が付与されており、好ましくは通版の検知をもとに版の処理面積を推定する機構が付与されており、好ましくは通版の検知および／または処理面積の推定をもとに補充しようとする補充液および／または水の補充量および／または補充タイミングを制御する機構が付与されており、好ましくは現像液の温度を制御する機構が付与されており、好ましくは現像液のｐＨおよび／または電導度を検知する機構が付与されており、好ましくは現像液のｐＨおよび／または電導度をもとに補充しようとする補充液および／または水の補充量および／または補充タイミングを制御する機構が付与されている。また、現像工程後に水洗工程がある場合、使用後の水洗水を現像濃縮液、現像補充液の濃縮液の希釈水として用いることができる。
【０１２２】
本発明に用いる自動現像機は、現像工程の前に前処理液に版を浸漬させる前処理部を有してもよい。この前処理部は、好ましくは版面に前処理液をスプレーする機構が付与されており、好ましくは前処理液の温度を２５℃〜５５℃の任意の温度に制御する機構が付与されており、好ましくは版面をローラー状のブラシにより擦る機構が付与されている。またこの前処理液としては、水などが用いられる。
【０１２３】
かかる組成の現像液で現像処理された版は水洗水、界面活性剤等を含有するリンス液、アラビアガムや澱粉誘導体等を主成分とするフィニッシャーや保護ガム液で後処理を施される。本発明のＰＳ版の後処理にはこれらの処理を種々組み合わせて用いることができ、例えば、現像後→水洗→界面活性剤を含有するリンス液処理や現像→水洗→フィニッシャー液による処理がリンス液やフィニッシャー液の疲労が少なく好ましい。更にリンス液やフィニッシャー液を用いた向流多段処理も好ましい態様である。これらの後処理は、一般に現像部と後処理部とからなる自動現像機を用いて行われる。後処理液は、スプレーノズルから吹き付ける方法、処理液が満たされた処理槽中を浸漬搬送する方法が用いられる。また、現像後一定量の少量の水洗水を版面に供給して水洗し、その廃液を現像液原液の希釈水として再利用する方法も知られている。このような自動処理においては、各処理液に処理量や稼働時間等に応じてそれぞれの補充液を補充しながら処理することができる。また、実質的に未使用の後処理液で処理するいわゆる使い捨て処理方式も適用できる。このような処理によって得られた平版印刷版は、オフセット印刷機に掛けられ、多数枚の印刷に用いられる。
【０１２４】
ガム液は現像液のアルカリ成分除去のため酸や緩衝剤を添加することが好ましく、その他に親水性高分子化合物、キレート剤、潤滑剤、防腐剤及び可溶化剤等を添加することができる。ガム液に親水性高分子化合物を含む場合は現像後の版の傷や汚れを防ぐ保護剤としての機能も付加される。
【０１２５】
本発明に用いられるガム液中に界面活性剤を添加することにより塗布層の面状等が良化する。使用できる界面活性剤としてはアニオン界面活性剤及び／又はノニオン界面活性剤が挙げられる。例えば、アニオン型界面活性剤としては、脂肪酸塩類、アビエチン酸塩類、ヒドロキシアルカンスルホン酸塩類、アルカンスルホン酸塩類、ジアルキルスルホコハク酸塩類、直鎖アルキルベンゼンスルホン酸塩類、分岐鎖アルキルベンゼンスルホン酸塩類、アルキルナフタレンスルホン酸塩類、アルキルフェノキシポリオキシエチレンプロピルスルホン酸塩類、ポリオキシエチレンアルキルスルホフェニルエーテル塩類、ポリオキシエチレンアリールエーテルスルホン酸塩、ポリオキシエチレンナフチルエーテルスルホン酸塩、Ｎ−メチル−Ｎ−オレイルタウリンナトリウム類、Ｎ−アルキルスルホコハク酸モノアミドニナトリウム塩類、石油スルホン酸塩類、硝酸化ヒマシ油、硫酸化牛脂油、脂肪酸アルキルエステルの硫酸エステル塩類、アルキル硝酸エステル塩類、ポリオキシエチレンアルキルエーテル硫酸エステル塩類、脂肪酸モノグリセリド硫酸エステル塩類、ポリオキシエチレンアルキルフェニルエーテル硫酸エステル塩類、ポリオキシエチレンスチリルフェニルエーテル硫酸エステル塩類、アルキル燐酸エステル塩類、ポリオキシエチレンアルキルエーテル燐酸エステル塩類、ポリオキシエチレンアルキルフェニルエーテル燐酸エステル塩類、スチレン−無水マレイン酸共重合物の部分ケン化物類、オレフィン−無水マレイン酸共重合物の部分ケン化物類、ナフタレンスルホン酸塩ホルマリン縮合物類等が挙げられる。これらの中でもジアルキルスルホコハク酸塩類、アルキル硫酸エステル塩類及びアルキルナフタレンスルホン酸塩類が特に好ましく用いられる。
【０１２６】
又、ノニオン界面活性剤としては、ポリオキシエチレンアルキルエーテル類、ポリオキシエチレンアルキルフェニルエーテル類、ポリオキシエチレンアリールエーテル類、ポリオキシエチレンナフチルエーテル、ポリオキシエチレンポリスチリルフェニルエーテル、ポリオキシエチレンポリオキシプロピレンアルキルエーテル、グリセリン脂肪酸部分エステル類、ソルビタン脂肪酸部分エステル類、ペンタエリスリトール脂肪酸部分エステル類、プロピレングリコールモノ脂肪酸エステル、ショ糖脂肪酸部分エステル、ポリオキシエチレンソルビタン脂肪酸部分エステル類、ポリオキシエチレンソルビトール脂肪酸部分エステル類、ポリエチレングリコール脂肪酸エステル類、ポリグリセリン脂肪酸部分エステル類、ポリオキシエチレン化ひまし油類、ポリオキシエチレングリセリン脂肪酸部分エステル類、脂肪酸ジエタノールアミド類、Ｎ，Ｎ−ビス−２−ヒドロキシアルキルアミン類、ポリオキシエチレンアルキルアミン、トリエタノールアミン脂肪酸エステル、トリアルキルアミンオキシド等が挙げられる。その中でもポリオキシエチレンアルキルフェニルエーテル類、ポリオキシエチレン−ポリオキシプロピレンブロックポリマー類等が好ましく用いられる。又、弗素系、シリコン系のアニオン、ノニオン界面活性剤も同様に使用することができる。これら界面活性剤は２種以上併用することもできる。例えば互いに異なる２種以上を併用することもできる。例えば互いに異なる２種以上のアニオン界面活性剤の併用やアニオン界面活性剤とノニオン界面活性剤の併用が好ましい。上記界面活性剤の使用量は特に限定する必要はないが、好ましくは後処理液の０．０１〜２０質量％である。
【０１２７】
本発明に用いられるガム液には、上記成分の他必要により潤滑剤として多価アルコール、アルコール及び脂肪族炭化水素を用いることができる。
【０１２８】
例えば、多価アルコールの内、好ましい具体例としては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、テトラエチレングリコール、ポリエチレングリコール、グリセリン、ソルビトール、プロピルアルコール、ブチルアルコール、ペンタノール、ヘキサノール、ヘプタノール、オクタノール、ペンジルアルコール、フェノキシエタノール、フェニルアミノエチルアルコール、ｎ−ヘキサノール、メチルアミルアルコール、２−エチルブタノール、ｎ−ヘプタノール、３−ヘプタノール、２−オクタノール、２−エチルヘキサノール、ノナノール、３，５，５−トリメチルヘキサノール、ｎ−デカノール、ウンデカノール、ｎ−ドデカノール、トリメチルノニルアルコール、テトラデカノール、ヘプタデカノール、２−エチル−１，３−ヘキサンジオール、１，６−ヘキサンジオール、２，５−ヘキサンジオール、２，４−ヘキサンジオール、１，８−オクタンジオール、１，９−ノナンジオール、１，１０−デカンジオール、グリセリン、トリメチロールプロパン等が好適に用いられる。これらの湿潤剤は単独で用いてもよいが、２種以上併用してもよい。一般に、上記湿潤剤は１〜２５質量％の量で使用するのが好ましい。
【０１２９】
皮膜形成性を向上させる目的で種々の親水性高分子を含有することができる。この様な親水性高分子としては従来よりガム液に使用し得るとされるものであれば好適に使用できる。例えば、アラビアガム、繊維素誘導体（例えば、カルボキシメチルセルロース、カルボキシエチルセルロース、メチルセルロース等）及びその変性体、ポリビニルアルコール及びその誘導体、ポリビニルピロリドン、ポリアクリルアミド及びその共重合体、ビニルメチルエーテル／無水マレイン酸共重合体、酢酸ビニル／無水マレイン酸共重合体、スチレン／無水マレイン酸共重合体等が挙げられる。
【０１３０】
本発明に用いられるガム液は、一般的には酸性領域ｐＨ３〜６の範囲で使用する方が有利である。ｐＨを３〜６にするためには一般的には後処理液中に鉱酸、有機酸又は無機塩等を添加して調節する。その添加量は０．０１〜２質量％が好ましい。例えば鉱酸としては硝酸、硫酸、リン酸及びメタリン酸等が挙げられる。
【０１３１】
又有機酸としては、クエン酸、酢酸、蓚酸、マロン酸、ｐ−トルエンスルホン酸、酒石酸、リンゴ酸、乳酸、レブリン酸、フィチン酸及び有機ホスホン酸等が挙げられる。更に無機塩としては、硝酸マグネシウム、第１リン酸ナトリウム、第２リン酸ナトリウム、硫酸ニッケル、ヘキサメタン酸ナトリウム、トリポリリン酸ナトリウム等が挙げられる。鉱酸、有機酸又は無機塩等の少なくとも１種もしくは２種以上を併用してもよい。
【０１３２】
本発明に用いられるガム液には、防腐剤、消泡剤等を添加することができる。例えば防腐剤としてはフェノール又はその誘導体、ホルマリン、イミダゾール誘導体、デヒドロ酢酸ナトリウム、４−イソチアゾリン−３−オン誘導体、ベンゾイソチアゾリン−３−オン、ベンズトリアゾール誘導体、アミジングアニジン誘導体、四級アンモニウム塩類、ピリジン、キノリン、グアニジン等の誘導体、ダイアジン、トリアゾール誘導体、オキサゾール、オキサジン誘導体等が挙げられる。好ましい添加量は、細菌、カビ、酵母等に対して、安定に効力を発揮する量であって、細菌、カビ、酵母の種類によっても異なるが、使用時の版面保護剤に対して０．０１〜４質量％の範囲が好ましく、又種々のカビ、殺菌に対して効力のある様に２種以上の防腐剤を併用することが好ましい。又、消泡剤としてはシリコン消泡剤が好ましい。その中で乳化分散型及び可溶化等が何れも使用できる。好ましくは使用時のガム液に対して０．０１〜１．０質量％の範囲が最適である。
【０１３３】
更にキレート化合物を添加してもよい。好ましいキレート化合物としては、例えば、エチレンジアミンテトラ酢酸、そのカリウム塩、そのナトリウム塩；ジエチレントリアミンペンタ酢酸、そのカリウム塩、そのナトリウム塩；トリエチレンテトラミンヘキサ酢酸、そのナトリウム塩；エチレンジアミンジコハク酸、そのカリウム塩、そのナトリウム塩；トリエチレンテトラミンヘキサ酢酸、そのカリウム塩、そのナトリウム塩、ヒドロキシエチルエチレンジアミントリ酢酸、そのカリウム塩、そのナトリウム塩：ニトリロトリ酢酸、そのナトリウム塩；１−ヒドロキシエタン−１，１−ジホスホン酸、そのカリウム塩、そのナトリウム塩；アミノトリ（メチレンホスホン酸）、そのカリウム塩、そのナトリウム塩等の様な有機ホスホン酸類或いはホスホノアルカントリカルボン酸類を挙げることが出来る。上記キレート剤のナトリウム塩、カリウム塩の代わりに有機アミンの塩も有効である。これらキレート剤はガム液組成中に安定に存在し、印刷性を阻害しないものが選ばれる。添加量としては使用時のガム液に対して０．００１〜１．０質量％が適当である。
【０１３４】
上記成分の他、必要により感脂化剤も添加することができる。例えばテレピン油、キシレン、トルエン、ローヘプタン、ソルベントナフサ、ケロシン、ミネラルスピリット、沸点が約１２０℃〜約２５０℃の石油留分等の炭化水素類、例えばジブチルフタレート、ジヘブチルフタレート、ジ−ｎ−オクチルフタレート、ジ（２−エチルヘキシル）フタレート、ジノニルフタレート、ジデシルフタレート、ジラウリルフタレート、ブチルベンジルフタレート等のフタル酸ジエステル剤、例えばジオクチルアジペート、ブチルグリコールアジペート、ジオクチルアゼレート、ジブチルセバケート、ジ（２−エチルヘキシル）セバケート、ジオクチルセバケート等の脂肪族二塩基酸エステル類、例えばエポキシ化大豆油等のエポキシ化トリグリセリド類、例えばトリクレジルフォスフェート、トリオクチルフォスフェート、トリスクロルエチルフォスフェート等のリン酸エステル類、例えば安息香酸ベンジル等の安息香酸エステル類等の凝固点が１５℃以下で、１気圧下での沸点が３００℃以上の可塑剤が含まれる。
【０１３５】
更にカプロン酸、エナント酸、カプリル酸、ヘラルゴン酸、カプリン酸、ウンデシル酸、ラウリン酸、トリデシル酸、ミリスチン酸、ペンタデシル酸、パルミチン酸、ヘプタデシル酸、ステアリン酸、ノナデカン酸、アラキン酸、ベヘン酸、リグノセリン酸、セロチン酸、ヘプタコサン酸、モンタン酸、メリシン酸、ラクセル酸、イソ吉草酸等の飽和脂肪酸とアクリル酸、クロトン酸、イソクロトン酸、ウンデシレン酸、オレイン酸、エライジン酸、セトレイン酸、ニルカ酸、ブテシジン酸、ソルビン酸、リノール酸、リノレン酸、アラキドン酸、プロピオール酸、ステアロール酸、イワシ酸、タリリン酸、リカン酸等の不飽和脂肪酸も挙げられる。より好ましくは５０℃において液体である脂肪酸であり、更に好ましくは炭素数が５〜２５であり、最も好ましくは炭素数が８〜２１である。これらの感脂化剤は１種もしくは２種以上併用することもできる。使用量として好ましい範囲はガムの０．０１〜１０質量％、より好ましい範囲は０．０５〜５質量％である。
【０１３６】
上記の様な感脂化剤は、ガムを乳化分散型としておき、その油相として含有させてもよく、又可溶化剤の助けを借りて可溶化してもよい。
【０１３７】
本発明において、ガム液の固型分濃度は５〜３０ｇ／ｌが好ましい。ガム膜厚量は自現機のスクイズ手段の条件で制御できる。本発明において、ガム塗布量は１〜１０ｇ／ｍ^２が好ましい。ガム塗布量は１０を越えると、短時間で乾燥するためには、版面を非常に高温にする必要があり、コスト上、安全上不利であり、また本発明の効果が十分に得られない。１ｇ／ｍ^２を下回ると、均一塗布が難しくなり、安定した処理性が得られない。
【０１３８】
本発明において、ガム液の塗布終了から乾燥開始までの時間は３秒以下であることが好ましい。更に好ましくは２秒以下であり、この時間が短いほどインキ着肉性が向上する。
【０１３９】
本発明において、乾燥時間は１〜５秒が好ましい。乾燥時間が５秒以上の時は本発明の効果が得られない。乾燥時間が１秒以下の場合には、感光性平版印刷版を十分に乾燥するために、版面を非常に高温にする必要があり、安全上、コスト上好ましくない。
【０１４０】
本発明において、乾燥方式としては、温風ヒーター、遠赤外線ヒーターなど公知の乾燥方式を用いることができる。
【０１４１】
乾燥工程では、ガム液中の溶媒が乾燥される必要がある。そのために十分な、乾燥温度とヒーター容量を確保する必要がある。乾燥に必要な温度は、ガム液の成分によって異なるが、溶媒が水であるガム液の場合は、通常乾燥温度は５５℃以上であることが好ましい。ヒーター容量は乾燥温度よりも重要で有る場合が多く、その容量は温風乾燥方式の場合は２．６ｋＷ以上が好ましい。容量は大きい程よいが、コストとのバランスで２．６〜７ｋＷが好ましい。
【０１４２】
本発明において、現像前の洗浄工程で用いる洗浄液は通常水であるが、必要に応じて以下の添加剤を加えることができる。
【０１４３】
キレート剤としては、金属イオンと配位結合してキレート化合物を形成する化合物を用いる。エチレンジアミンテトラ酢酸、そのカリウム塩、そのナトリウム塩、エチレンジアミンジコハク酸、そのカリウム塩、そのナトリウム塩、トリエチレンテトラミンヘキサ酢酸、そのカリウム塩、そのナトリウム塩、ジエチレントリアミンペンタ酢酸、そのカリウム塩、そのナトリウム塩、ヒドロキシエチルエチレンジアミントリ酢酸、そのカリウム塩、そのナトリウム塩、ニトリオトリ酢酸、そのカリウム塩、そのナトリウム塩、１−ヒドロキシエタン−１，１−ジホスホン酸、そのカリウム塩、そのナトリウム塩、アミノトリ（メチレンホスホン酸）、そのカリウム塩、そのナトリウム塩、ホスホノアルカントリカルボン酸、エチレンジアミンジコハク酸、そのカリウム塩、そのナトリウム塩等が挙げられる。これらのキレート剤はカリウム塩及びナトリウム塩の代わりに有機アミン塩を有するものも有効である。キレート剤の添加量は０〜３．０質量％の範囲が適当である。
【０１４４】
界面活性剤としては、アニオン、ノニオン、カチオン及び両性の何れの界面活性剤も用いることができるが、アニオン又はノニオン界面活性剤が好ましい。好ましい界面活性剤の種類はオーバーコート層や感光層の組成によって異なり、一般にオーバーコート層素材の溶解促進剤となり、感光層成分の溶解性が小さいものが好ましい。
【０１４５】
アニオン界面活性剤としては、脂肪酸塩類、アビチェン酸塩類、ヒドロキシアルカンスルホン酸塩類、アルカンスルホン酸塩類、ジアルキルスルホコハク酸塩類、アルキルベンゼンスルホン酸塩類、アルキルナフタレンスルホン酸塩類、アルキルフェノキシポリオキシエチレンプロピルスルホン酸塩類、ポリオキシエチレンアルキルスルホフェニルエーテル塩類、Ｎ−メチル−Ｎ−オレイルタウリンナトリウム類、Ｎ−アルキルスルホコハク酸モノアミド二ナトリウム塩類、石油スルホン酸塩類、硫酸化ヒマシ油、硫酸化牛脂油、脂肪酸アルキルエステルの硫酸エステル塩類、アルキル硫酸エステル塩類、ポリオキシエチレンアルキルエーテル硫酸エステル塩類、脂肪酸モノグリセリド硫酸エステル塩類、ポリオキシエチレンスチリルフェニルエーテル硫酸エステル塩類、アルキル燐酸エステル塩類、ポリオキシエチレンアルキルエーテル燐酸エステル塩類、ポリオキシエチレンアルキルフェニルエーテル燐酸エステル塩類、スチレン−無水マレイン酸共重合物の部分ケン化物類、オレフィン−無水マレイン酸共重合物の部分ケン化物類、ナフタレンスルホン酸塩ホルマリン縮合物類等が挙げられる。
【０１４６】
ノニオン界面活性剤としては、ポリオキシエチレンアルキルエーテル類、ポリオキシエチレンアルキルフェニルエーテル類、ポリオキシエチレンポリスチリルフェニルエーテル類、ポリオキシエチレンポリオキエイプロピレンアルキルエーテル類、グリセリン脂肪酸エステル類、ソルビタン脂肪酸部分エステル類、ペンタエリスリトール脂肪酸部分エステル類、プロピレングリコールモノ脂肪酸エステル、ショ糖脂肪酸部分エステル類、ポリオキシエチレンソルビタン脂肪酸部分エステル類、イエチレングリコール脂肪酸エステル類、ポリイグリセリン脂肪酸部分エステル類、ポリオキシエチレン化ひまし油類、ポリオキシエチレングリセリン脂肪酸部分エステル類、脂肪酸ジエタノールアミド類、Ｎ，Ｎ−ビス−ヒドロキシアルキルアミン類、ポリオキシエチレンアルキルアミン、トリエタノールアミン脂肪酸エステル、トリアルキルアミンオキシド等が挙げられる。
界面活性剤の好ましい添加量は０〜１０質量％である。また、界面活性剤に消泡剤を併用することもできる。
【０１４７】
防腐剤としては、フェノール又はその誘導体、ホルマリン、イミダゾール誘導体、デヒドロ酢酸ナトリウム、４−イソチアゾリン−３−オン誘導体、ベンゾイソチアゾリン−３−オン、ベンゾトリアゾール誘導体、アミジングアニジン誘導体、四級アンモニウム塩類、ピロジン，キノリン，グアニジン等の誘導体、ダイアジン、トリアゾール誘導体、オキサゾール，オキサジン誘導体等が挙げられる。
【０１４８】
本発明の洗浄方法において、現像前洗浄に用いる洗浄液は温度を調節して用いることが好ましく、該温度は１０〜６０℃の範囲が好ましい。洗浄の方法は、スプレー、ディップ、塗布等公知の処理液供給技術を用いることができ、適宜ブラシや絞りロール、ディップ処理における液中シャワーなどの処理促進手段を用いることができる。
【０１４９】
本発明において、現像前洗浄工程終了後直ちに現像処理を行ってもよく、また、現像前洗浄工程の後に乾燥させてから現像処理を行ってもよい。現像工程の後は、水洗、リンス、ガム引き等公知の後処理を行うことができる。一度以上使用した現像前水洗水は、現像後の水洗水やリンス液、ガム液に再使用することができる。
【０１５０】
本発明の感光性平版印刷版材料は、画像形成後、印刷機により印刷を行うが、印刷機、印刷用紙、印刷インキ、湿し水等特に限定されない。近年印刷業界においても環境保全が叫ばれ、印刷インキにおいては石油系の揮発性有機化合物（ＶＯＣ）を使用しないインキが開発されその普及が進みつつあるが、本発明の効果はこのような環境対応の印刷インキを使用した場合に特に顕著である。環境対応の印刷インキとしては大日本インキ化学工業社製の大豆油インキ“ナチュラリス１００”、東洋インキ社製のＶＯＣゼロインキ“ＴＫハイエコーＮＶ”、東京インキ社製のプロセスインキ“ソイセルボ”等があげられる。
【０１５１】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されない。尚、実施例における「部」は、特に断りない限り「質量部」を表す。
【０１５２】
実施例１
（高分子結合剤Ｂ−１の合成）
窒素気流下の三ツ口フラスコに、メチルメタクリレート（１２５部：１．２５モル）、エチルメタクリレート（１２部：０．１０モル）、メタクリル酸（６３部：０．７３モル）、シクロヘキサノン（２４０部）、イソプロピルアルコール（１６０部）及びα，α′−アゾビスイソブチロニトリル（５部）を入れ、窒素気流中８０℃のオイルバスで６時間反応させて高分子重合体を得た。その後、該重合体に、トリエチルベンジルアンモニウムクロライド４部及びグリシジルメタクリレート（５２部：０．７３モル）を加えて、温度２５℃で３時間反応させて高分子結合剤Ｂ−１を得た。質量平均分子量は約５５，０００（ＧＰＣ：ポリスチレン換算）であった。
【０１５３】
（支持体の作製）
厚さ０．３ｍｍのアルミニウム板（材質１０５０，調質Ｈ１６）を６５℃に保たれた５％水酸化ナトリウム水溶液に浸漬し、１分間の脱脂処理を行った後、水洗した。この脱脂アルミニウム板を、２５℃に保たれた１０％塩酸水溶液中に１分間浸漬して中和した後、水洗した。次いで、このアルミニウム板を、１．５質量％の塩酸水溶液中で、２５℃、電流密度６０Ａ／ｄｍ^２の条件下に交流電流により３０秒間、電解粗面化を行った。その後５０℃に保たれた１％水酸化ナトリウム水溶液中で１０秒間のデスマット処理を行った。デスマット処理を行った粗面化アルミニウム板を、３０％硫酸溶液中で、２５℃、電流密度３０Ａ／ｄｍ^２、電圧２５Ｖの条件下に３０秒間陽極酸化処理を行った。
【０１５４】
（ポリビニルホスホン酸処理）
上記支持体を、０．４４％のポリビニルホスホン酸水溶液に、７５℃、３０秒間ディップ処理を行い、次いで蒸留水で水洗し、２５℃の冷風で乾燥し、感光性平版印刷版用支持体Ａを得た。
【０１５５】
上記方法と同様に、塩酸による電解粗面化条件、デスマット条件を種々変更し、また、陽極酸化処理後に酢酸アンモニウムを含む水溶液中での封孔処理を条件変更し、感光性平版印刷版用支持体Ｂ〜Ｊを得た。作製条件と得られたＲａ、微細粗面の結果を表１に示す。また支持体Ａ、Ｄ、Ｇの電子顕微鏡写真をそれぞれ図１〜３に示す。
【０１５６】
表面粗さＲａは非接触三次元微小表面形状測定システム（Ｖｅｅｃｏ社製ＷＹＫＯ）で４０倍にて測定した。微細粗面の平均間隔または平均径が３０〜１５０ｎｍで構成される凹凸部の個数は、日立走査型電子顕微鏡Ｓ−５０００Ｈにて、Ｐｔ−Ｐｄ；１ｎｍコーティング、加速電圧５ｋＶ、傾斜角；０度、倍率１０００００倍にて表面を観察し求めた。
【０１５７】
【表１】

【０１５８】
（感光性平版印刷版材料１〜１０の作製）
上記表面処理済み支持体上に、下記組成の光重合性感光層塗布液を乾燥時１．５ｇ／ｍ^２になるようワイヤーバーで塗布し、９５℃で１．５分間乾燥した。その後、更に該感光層上に、下記組成の保護層塗布液を乾燥時２．０ｇ／ｍ^２になるようにアプリケーターで塗布し、７５℃で１．５分間乾燥して、感光層上に保護層を有する感光性平版印刷版材料を作製した。
【０１５９】

【０１６０】
【化２】

【０１６１】
（画像形成）
このようにして作製した光重合型の感光性平版印刷版材料について、４０８ｎｍ、３０ｍＷ出力のレーザー光源を備えたプレートセッター（タイガーキャット：ＥＣＲＭ社製改造品）を用いて２４００ｄｐｉ（ｄｐｉとは１インチ即ち２．５４ｃｍ当たりのドット数を表す）の解像度で画像露光を行った。次いで、現像前に、加熱装置部、保護層を除去する前水洗部、下記現像液組成を充填した現像部、版面に付着した現像液を取り除く水洗部、画線部保護のためのガム液（ＧＷ−３：三菱化学社製を２倍希釈したもの）を備えたＣＴＰ自動現像機（ＰＨＷ２３−Ｖ：Ｔｅｃｈｎｉｇｒａｐｈ社製）で現像処理を行い、平版印刷版材料１〜１０を得た。このとき加熱装置部は、版面温度１１５℃、版滞在時間１５秒となるように設定した。また露光終了から自現機の加熱装置部への版挿入は６０秒以内に行った。
【０１６２】
現像液組成（下記添加剤を含有する水溶液）
珪酸カリウム水溶液（ＳｉＯ_２：２６％、Ｋ_２Ｏ：１３．５％） ４０．０ｇ／Ｌ
水酸化カリウム ４．０ｇ／Ｌ
エチレンジアミンテトラ酢酸 ０．５ｇ／Ｌ
ポリオキシエチレン（１３）ナフチルエーテルスルホン酸塩 ２０．０ｇ／Ｌ
水にて１Ｌとした。ｐＨは１２．３であった。
【０１６３】
（平版印刷版の評価）
上記のようにして得られた感光性平版印刷版材料について、以下の評価をした。評価結果を表２に示す。
【０１６４】
（感度）
感光性平版印刷版材料に１７５線の画像を露光、現像して平版印刷版を作製し、平版印刷版の版面に記録された１００％画像部において、膜減りが観察されない最低量の露光エネルギー量の２倍を記録エネルギーとし、感度の指標とした。記録エネルギーが小さい程高感度であることを表す。
【０１６５】
（耐刷性）
感光性平版印刷版材料に１７５線の画像を１００μＪ／ｃｍ^２露光量で露光、現像して作製した平版印刷版を、印刷機（ＤＡＩＹＡ１Ｆ−１：三菱重工業製）で、コート紙、印刷インキ（大豆油インキ ナチュラリス１００：大日本インキ化学工業社製）及び湿し水（Ｈ液ＳＧ−５１ 濃度１．５％：東京インク社製）を用いて印刷を行い、ハイライト部の点細り、シャドウ部の絡みの発生する印刷枚数を耐刷性を示す指標として示す。印刷枚数が多いほど高耐刷性であることを表す。
【０１６６】
（汚れ性）
上記と同条件で印刷を行い、刷り出しから２０００枚印刷した。その後３分間空転放置し、版面の湿し水を完全に乾燥した後、インキ着けローラーを版面に５回転接触させ版全面にインキを付着させた。印刷をスタートし、全面地汚れの状態から非画像部の汚れが回復するまでの印刷枚数を汚れ性の指標として示す。回復枚数が少ないものが良好であることを表す。
【０１６７】
（プレートクリーナー適性）
上記と同様の印刷条件で、５００枚印刷ごとにウルトラプレートクリーナー（ＡＢＣケミカル社製）で版面を１分間スポンジで洗浄し、３分間放置後、スポンジで水洗し印刷を再開した。同操作を繰り返し行い、ベタ部にインキが載らなくなる回数を、プレートクリーナー適性の指標とした。回数が多いほどプレートクリーナー適性が高いことを表す。
【０１６８】
（網点再現性）
感光性平版印刷版材料に１７５線の網点パターンをリニアリティー補正なしで１００μＪ／ｃｍ^２露光量で露光、現像して作製した平版印刷版について、網点％の再現域を網点再現性の指標とした。ハイライト部からシャドウ部まで再現域が広いほど網点再現性が優れることを表す。
【０１６９】
【表２】

【０１７０】
表２から、本発明の支持体を用いた感光性平版印刷版材料はいずれも高感度、高耐刷、汚れ性、プレートクリーナー適性、網点再現性に優れていることが分かる。
【０１７１】
実施例２
支持体の作製を以下のように変更した以外は、実施例１と同様に感光性平版印刷版材料を作製し、同様の評価を行った。
【０１７２】
（支持体の作製）
厚さ０．３ｍｍのアルミニウム板（材質１０５０，調質Ｈ１６）を８号ナイロンブラシと８００メッシュのパミストンの水懸濁液を用い、その表面を砂目立てした後、よく水で洗浄した。１０％水酸化ナトリウムに７０℃で６０秒間浸漬してエッチングした後、流水で、水洗後、２０％ＨＮＯ_３で中和洗浄、水洗した。次いで、このアルミニウム板を、０．７質量％の塩酸水溶液中で、２５℃、電流密度５０Ａ／ｄｍ^２の条件下に交流電流により４０秒間、電解粗面化を行った。その後５０℃に保たれた０．８％水酸化ナトリウム水溶液中で１０秒間のデスマット処理を行った。デスマット処理を行った粗面化アルミニウム板を、３０％硫酸溶液中で、２５℃、電流密度３０Ａ／ｄｍ^２、電圧２５Ｖの条件下に３０秒間陽極酸化処理を行った。
【０１７３】
（ポリビニルホスホン酸処理）
上記支持体を、０．４４％のポリビニルホスホン酸水溶液に、７５℃、３０秒間ディップ処理を行い、次いで蒸留水で水洗し、２５℃の冷風で乾燥し、感光性平版印刷版用支持体Ｋを得た。
【０１７４】
上記方法と同様に、塩酸による電解粗面化条件、デスマット条件を種々変更し、また、陽極酸化処理後に酢酸アンモニウムを含む水溶液中での封孔処理を条件変更し、感光性平版印刷版用支持体Ｌ〜Ｓを得た。作製条件と得られたＲａ、微細粗面の結果を表３に示す。
【０１７５】
【表３】

【０１７６】
評価結果を表４に示す。
【０１７７】
【表４】

【０１７８】
表４から、本発明の支持体を用いた感光性平版印刷版材料はいずれも高感度、高耐刷、汚れ性、プレートクリーナー適性、網点再現性に優れていることが分かる。
【０１７９】
実施例３
支持体の作製を以下のように変更した以外は、実施例１と同様に感光性平版印刷版材料を作製し、同様の評価を行った。
【０１８０】
（支持体の作製）
厚さ０．３ｍｍのアルミニウム板（材質１０５０，調質Ｈ１６）を６５℃に保たれた５％水酸化ナトリウム水溶液に浸漬し、１分間の脱脂処理を行った後、水洗した。この脱脂アルミニウム板を、２５℃に保たれた１０％塩酸水溶液中に１分間浸漬して中和した後、水洗した。次いで、このアルミニウム板を、１．５質量％の硝酸水溶液中で、２５℃、電流密度４０Ａ／ｄｍ^２の条件下に交流電流により２０秒間、電解粗面化を行った。その後５０℃に保たれた１％水酸化ナトリウム水溶液中で１０秒間のデスマット処理を行った。デスマット処理を行った粗面化アルミニウム板を、３０％硫酸溶液中で、２５℃、電流密度３０Ａ／ｄｍ^２、電圧２５Ｖの条件下に３０秒間陽極酸化処理を行った。次いで８５℃に保たれた０．１％の酢酸アンモニウム水溶液により１０秒間封孔処理を行った。
【０１８１】
（ポリビニルホスホン酸処理）
上記支持体を、０．４４％のポリビニルホスホン酸水溶液に、７５℃、３０秒間ディップ処理を行い、次いで蒸留水で水洗し、２５℃の冷風で乾燥し、感光性平版印刷版用支持体Ｔを得た。
【０１８２】
上記方法と同様に、硝酸による電解粗面化条件、デスマット条件、陽極酸化処理後に酢酸アンモニウムを含む水溶液中での封孔処理を条件変更し、感光性平版印刷版用支持体Ｕ〜Ｚを得た。作製条件と得られたＲａ、微細粗面の結果を表５に示す。
【０１８３】
【表５】

【０１８４】
評価結果を表６に示す。
【０１８５】
【表６】

【０１８６】
表６から、本発明の支持体を用いた感光性平版印刷版材料はいずれも高感度、高耐刷、汚れ性、プレートクリーナー適性、網点再現性に優れていることが分かる。
【０１８７】
実施例４
支持体の作製を以下のように変更した以外は、実施例１と同様に感光性平版印刷版材料を作製し、同様の評価を行った。
【０１８８】
（支持体の作製）
厚さ０．３ｍｍのアルミニウム板（材質１０５０，調質Ｈ１６）を８号ナイロンブラシと８００メッシュのパミストンの水懸濁液を用い、その表面を砂目立てした後、よく水で洗浄した。１０％水酸化ナトリウムに７０℃で６０秒間浸漬してエッチングした後、流水で、水洗後、２０％ＨＮＯ_３で中和洗浄、水洗した。次いで、このアルミニウム板を、１．０質量％の硝酸水溶液中で、２５℃、電流密度３０Ａ／ｄｍ^２の条件下に交流電流により２０秒間、電解粗面化を行った。その後５０℃に保たれた１％水酸化ナトリウム水溶液中で１０秒間のデスマット処理を行った。デスマット処理を行った粗面化アルミニウム板を、３０％硫酸溶液中で、２５℃、電流密度３０Ａ／ｄｍ^２、電圧２５Ｖの条件下に３０秒間陽極酸化処理を行った。次いで８５℃に保たれた０．１２％の酢酸アンモニウム水溶液により１０秒間封孔処理を行った。
【０１８９】
（ポリビニルホスホン酸処理）
上記支持体を、０．４４％のポリビニルホスホン酸水溶液に、７５℃、３０秒間ディップ処理を行い、次いで蒸留水で水洗し、２５℃の冷風で乾燥し、感光性平版印刷版用支持体ＡＡを得た。
【０１９０】
上記方法と同様に、硝酸による電解粗面化条件、デスマット条件、陽極酸化処理後に酢酸アンモニウムを含む水溶液中での封孔処理を条件変更し、感光性平版印刷版用支持体ＡＢ〜ＡＧを得た。作製条件と得られたＲａ、微細粗面の結果を表７に示す。
【０１９１】
【表７】

【０１９２】
評価結果を表８に示す。
【０１９３】
【表８】

【０１９４】
表８から、本発明の支持体を用いた感光性平版印刷版材料はいずれも高感度、高耐刷、汚れ性、プレートクリーナー適性、網点再現性に優れていることが分かる。
【０１９５】
【発明の効果】
本発明により、高感度、高耐刷、汚れ性、プレートクリーナー適性、網点再現性に優れた３５０ｎｍから４５０ｎｍ域でのレーザー露光に対応した感光性平版印刷版材料及びその画像形成方法を提供することができた。
【図面の簡単な説明】
【図１】支持体Ａの電子顕微鏡写真である。
【図２】支持体Ｄの電子顕微鏡写真である。
【図３】支持体Ｇの電子顕微鏡写真である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photopolymerizable photosensitive lithographic printing plate material and an image forming method for the photopolymerizable photosensitive lithographic printing plate material.
[0002]
[Prior art]
Conventionally, a photosensitive composition using a photopolymerization system is well known. Further, a photopolymerizable photosensitive composition layer (hereinafter, sometimes referred to as a photopolymerizable photosensitive layer or simply a photosensitive layer) is provided on a support that has been subjected to a surface roughening treatment, an anodic oxidation treatment, and if necessary, a hydrophilic treatment. And a photosensitive lithographic printing plate material having a protective layer laminated thereon.
[0003]
The photopolymerizable photosensitive layer generally contains an acrylic monomer, an alkali-soluble resin, a photopolymerizable initiator, and, if necessary (especially when performing laser writing), a sensitizing dye to adjust the wavelength. It is known to It is also known to provide a protective layer for the purpose of preventing polymerization inhibition by oxygen.
[0004]
In recent years, in order to quickly obtain a high-resolution lithographic printing plate material and, for the purpose of filmlessness, perform digital exposure based on image information using a laser and develop it to produce a lithographic printing plate. The method has been generalized.
[0005]
For example, an output signal from an electronic plate making system or an image processing system or an image signal transmitted through a communication line or the like modulates a light source and directly scans and exposes a photosensitive material to form a printing plate. There are known systems.
[0006]
As a light source for laser exposure and plate making of the photopolymerizable photosensitive lithographic printing plate material, a light source such as an Ar laser (488 nm), an FD-YAG laser (532 nm), or a high-power semiconductor laser emitting light in a region of 750 nm or more is used. A visible light source of a wavelength is used. Furthermore, in recent years, for example, a semiconductor laser (hereinafter, sometimes referred to as a violet laser) using an InGaN-based or ZnSe-based material and capable of continuously oscillating in a range of 350 nm to 450 nm has been put into practical use. The scanning exposure system using these short-wave light sources has the advantage that an economical system can be constructed while having a sufficient output because a semiconductor laser can be manufactured inexpensively due to its structure. Furthermore, as compared with a system using a conventional FD-YAG or Ar laser, there is a possibility that the photosensitive region capable of working under a brighter safelight can be used for a photosensitive lithographic printing plate material having a short wavelength.
[0007]
At present, a photosensitive lithographic printing plate capable of supporting violet laser exposure has been marketed as a silver salt diffusion method capable of supporting a 5 mW output laser. However, due to advances in laser technology, a 30 mW output laser has become a practical stage, and a less expensive photopolymerization method has been developed. A photosensitive lithographic printing plate material of the type is desired.
[0008]
Photopolymerizable photosensitive lithographic printing plate materials are usually subjected to image exposure and, if necessary, heat treatment, followed by washing to remove the protective layer, developing to dissolve and remove unexposed portions, washing with water, A lithographic printing plate was obtained by performing a finisher gum treatment for making the image area hydrophilic. At this time, it is known that, by performing a heat treatment after the image exposure, a polymerization reaction is promoted, and high sensitivity and high printing durability can be obtained.
[0009]
On the other hand, a developer for the photosensitive lithographic printing plate material is usually used as an aqueous alkaline developer at a pH of 12.5 or more to completely remove the photosensitive layer in the non-image area, that is, to perform development. Was common. However, recently, from the viewpoints of workability, safety, environmental suitability, and the like, development with an aqueous alkaline developer having a lower pH has been desired.
[0010]
At present, the photopolymerizable photosensitive lithographic printing plate materials as described above have not been found to satisfy both sensitivity, printing durability and stain resistance. In particular, it has poor suitability for chemicals such as a plate cleaner used for preventing stains during printing, and causes poor printing durability.
[0011]
In recent years, environmental conservation has also been called out in the printing industry, and inks that do not use petroleum-based volatile organic compounds (VOCs) have been developed as printing inks and their use has been spreading. At present, it is difficult to achieve both high printing durability and stain resistance by printing using such an ink.
[0012]
Further, at present, it is difficult to achieve both high sensitivity, high printing durability and stain resistance by laser exposure in the range of 350 nm to 450 nm. In addition, since light is scattered by the support for drawing using a high output laser. It was susceptible to influence and the dot reproducibility from highlight to shadow was insufficient.
[0013]
A support in which the diameter and the density of the micropores are specified by anodic oxidation (for example, see Patent Literatures 1 and 2), a support in which the surface roughness Ra is specified (for example, see Patent Literatures 3 and 4), on the order of several micrometers. (See, for example, Patent Document 5) which defines a rough surface structure for determining Ra and micropores of several nm. However, the performance of such a support was insufficient.
[0014]
[Patent Document 1]
JP-A-2001-264978 (Claims)
[0015]
[Patent Document 2]
JP 2002-196506 A (Claims)
[0016]
[Patent Document 3]
JP-A-2002-229187 (Claims)
[0017]
[Patent Document 4]
JP 2003-43703 A (Claims)
[0018]
[Patent Document 5]
JP 2003-1956 A (Claims)
[0019]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive lithographic printing plate material and a method for forming an image thereof, which are compatible with laser exposure in the range of 350 nm to 450 nm and have high sensitivity, high printing durability, stain resistance, suitability for a plate cleaner, and excellent dot reproducibility. To provide.
[0020]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following configurations.
[0021]
1. A photopolymerization initiator, a polymer binder, an addition-polymerizable ethylenically unsaturated bond-containing monomer and an absorption maximum between 350 nm and 450 nm are provided on a support that has been subjected to at least roughening treatment and anodizing treatment. In a photosensitive lithographic printing plate material obtained by coating a photosensitive composition containing a sensitizing dye having a surface roughness Ra of the support of 0.4 to 0.8 μm, and an average interval or average 50 to 1100 irregularities with a diameter of 30 to 150 nm / μm ² A photosensitive lithographic printing plate material having a fine rough surface.
[0022]
2. 2. The photosensitive lithographic printing plate material as described in 1 above, wherein the fine rough surface of the support is a rough surface formed by an alternating current electrolytic treatment in an acidic electrolytic solution mainly containing hydrochloric acid.
[0023]
3. 2. The photosensitive lithographic printing plate material as described in 1 above, wherein the fine rough surface of the support is a rough surface formed by sealing after anodic oxidation.
[0024]
4. 4. The photosensitive lithographic printing plate material as described in any one of the above items 1 to 3, wherein the support has been subjected to a hydrophilization treatment before the photosensitive composition is applied.
[0025]
5. 5. The photosensitive lithographic printing plate material as described in any one of the above items 1 to 4, wherein the photopolymerization initiator is an iron arene complex compound.
[0026]
6. The photosensitive composition contains a trihaloalkyl compound and an addition-polymerizable ethylenically unsaturated bond-containing monomer containing a group that can be oxidized by light, The photosensitive composition according to any one of the above items 1 to 5, wherein Photosensitive lithographic printing plate material.
[0027]
7. 7. The photosensitive lithographic printing plate material according to any one of 1 to 6, above, is image-exposed to a photosensitive composition layer of the photosensitive lithographic printing plate material imagewise by exposing the photosensitive lithographic printing plate material to an image with a laser beam of 350 nm to 450 nm. Forming a photosensitive lithographic printing plate material image, wherein the unexposed portion of the photosensitive composition layer is removed from the support with an alkali developing solution.
[0028]
The present invention will be described in more detail. In the present invention, the presence and the number of the Ra of the support and the unevenness having an average spacing or an average diameter of 30 to 150 nm which is larger than the micropores by anodization and not involved in the determination of Ra are 350 nm. The present invention has been found to obtain a photopolymerizable photosensitive lithographic printing plate material capable of forming an image by laser exposure in the range of from 450 to 450 nm while achieving both high sensitivity, high printing durability, stain resistance, and suitability for a plate cleaner. In addition, the present invention has been found to be particularly remarkable when an environmentally friendly printing ink is used, and has also been found to be excellent in halftone dot reproducibility during high-power laser exposure.
[0029]
Preferred examples of the photopolymerization initiator used in the photosensitive lithographic printing plate material of the present invention include titanocene compounds, monoalkyltriarylborate compounds, and iron arene complex compounds.
[0030]
Examples of the titanocene compound include compounds described in JP-A-63-41483 and JP-A-2-291. More preferred specific examples are bis (cyclopentadienyl) -Ti-di-chloride. , Bis (cyclopentadienyl) -Ti-bis-phenyl, bis (cyclopentadienyl) -Ti-bis-2,3,4,5,6-pentafluorophenyl, bis (cyclopentadienyl) -Ti -Bis-2,3,5,6-tetrafluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4,6-trifluorophenyl, bis (cyclopentadienyl) -Ti-bis-2 , 6-Difluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4-difluorophenyl, bis (methylcyclopentadienyl) -Ti-bi -2,3,4,5,6-pentafluorophenyl, bis (methylcyclopentadienyl) -Ti-bis-2,3,5,6-tetrafluorophenyl, bis (methylcyclopentadienyl) -Ti -Bis-2,6-difluorophenyl (IRUGACURE727L: manufactured by Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrid-1-yl) phenyl) titanium (IRUGACURE784) : Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,4,6-trifluoro-3- (pyr-1-yl) phenyl) titanium bis (cyclopentadienyl) -bis ( 2,4,6-trifluoro-3- (2-5-dimethylpyr-1-yl) phenyl) titanium And the like.
[0031]
Examples of the monoalkyltriaryl borate compound include compounds described in JP-A-62-150242 and JP-A-62-143044. More preferred specific examples include tetra-n-butylammonium. n-butyl-trinaphthalen-1-yl-borate, tetra-n-butylammonium / n-butyl-triphenyl-borate, tetra-n-butylammonium / n-butyl-tri- (4-tert-butylphenyl) -borate And tetra-n-butylammonium / n-hexylrytoly (3-chloro-4-methylphenyl) -borate, tetra-n-butylammonium / n-hexyllytoly ((3-fluorophenyl) -borate, and the like.
[0032]
Examples of the iron arene complex compound include compounds described in JP-A-59-219307, and more preferred specific examples are η-benzene- (η-cyclopentadienyl) iron hexafluorophosphate and η-benzene. Cumene- (η-cyclopentadienyl) iron hexafluorophosphate, η-fluorene- (η-cyclopentadienyl) iron hexafluorophosphate, η-naphthalene- (η-cyclopentadienyl) iron hexafluoro Phosphate, η-xylene- (η-cyclopentadienyl) iron hexafluorophosphate, η-benzene- (η-cyclopentadienyl) irontetrafluoroborate and the like can be mentioned.
In the present invention, a titanocene compound and an iron arene complex compound are particularly preferable. Further, an iron arene complex compound is preferable from the viewpoint of safelight.
[0033]
In addition, any photopolymerization initiator can be used in combination. For example, Carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes as described in Chapter 5 of "Light Sensitive Systems" by J. Kosar. And the like. More specific compounds are disclosed in British Patent 1,459,563.
[0034]
That is, the following can be used as the photopolymerization initiator that can be used in combination.
[0035]
Benzoin derivatives such as benzoin methyl ether, benzoin-i-propyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4′-bis (dimethyl Benzophenone derivatives such as amino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-i-propylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; N-methylacridone and N-butylacridone And α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone and uranyl compounds, as well as those described in JP-B-59-1281, JP-B-61-9621 and JP-A-60-60104. Triazine derivatives; organic peroxides described in JP-A-59-1504 and JP-A-61-243807; JP-B-43-23684, JP-A-44-6413, JP-A-44-6413, JP-A-47-1604 and U.S. Pat. No. 3,567,453; organic azide compounds described in U.S. Pat. Nos. 2,848,328, 2,852,379 and 2,940,853; Japanese Patent Publication Nos. 36-22062b and 37. O-Quinonediazides described in JP-13109, JP38-18015, and JP45-9610; JP-B-55-39162, JP-A-59-14023, and "Macromolecules", Vol. Various onium compounds described on page 1977; azo described in JP-A-59-142205. Compounds: described in JP-A-1-54440, European Patent Nos. 109,851, 126,712 and "Journal of Imaging Science (J. Imag. Sci.)", Vol. 30, p. 174 (1986). (Oxo) sulfonium organoboron complexes described in JP-A-5-213861 and JP-A-5-255347; "Coordination Chemistry Review," Vol. 84, pp. 85-277 (1988). And a transition metal complex containing a transition metal such as ruthenium described in JP-A-2-182701; a 2,4,5-triarylimidazole dimer described in JP-A-3-209777; carbon tetrabromide; Organic halogen compounds described in No. 59-107344, etc.
[0036]
The photosensitive composition and the photosensitive lithographic printing plate material of the present invention have an addition-polymerizable ethylenically unsaturated bond-containing monomer containing a photo-oxidizable group as an addition-polymerizable ethylenically unsaturated bond-containing monomer. When a compound is used, it is preferable to contain a compound containing a photodegradable trihaloalkyl group known as a free radical-forming photoinitiator for a photopolymerizable mixture. Compounds containing chlorine and bromine as halogens are particularly suitable as combined initiators of this type. The trihaloalkyl group is preferably a trihalomethyl group, and is preferably bonded to an aromatic carbocyclic or heterocyclic ring directly or via a continuously conjugated chain. Those having a triazine ring having two trihalomethyl groups as a mother nucleus, particularly those of EP-A-137,452, DE-A-2,118,259 and DE-A-2,243,621 The compounds described in each specification are preferred. These compounds exhibit strong light absorption in the near ultraviolet region, for example, 350 to 400 nm. Co-initiators that do not themselves or only slightly absorb in the spectral region of the copying light, such as trihalomethyltriazines containing substituents with short electronic systems or aliphatic substituents that enable mesomeries, Is also appropriate. Also suitable are compounds having a different basic skeleton and which absorb light in the short-wave ultraviolet region, for example phenyltrihalomethylsulphone or phenyltrihalomethylketone, for example phenyltribromomethylsulphone.
[0037]
As the sensitizing dye having an absorption maximum between 350 nm and 450 nm used in the photosensitive lithographic printing plate material of the present invention, those which can be preferably used are not particularly limited in structure, but are cyanine, phthalocyanine, merocyanine, porphyrin, spiro compound. , Ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, phenothiazine, polyene, azo compound, diphenylmethane, triphenylmethane, polymethine acridine, coumarin, coumarin, coumarin derivative, ketocoumarin, quinacridone, indigo, styryl, pyrylium compound, pyrromethene compound, pyrazolo Dyes such as triazole compounds, benzothiazole compounds, barbituric acid derivatives, thiobarbituric acid derivatives, and other keto alcohol borate complexes are limited to those whose absorption maximum meets the requirements. , Both of which it is available. Specifically, JP-A-2002-296564, JP-A-2002-268239, JP-A-2002-268238, JP-A-2002-268204, JP-A-2002-221790, JP-A-2002-202598, and JP-A-2001 -42524, JP-A-2000-309724, JP-A-2000-258910, JP-A-2000-206690, JP-A-2000-147763, and dyes described in JP-A-2000-98605 can be used. , But is not limited to this.
[0038]
The amounts of the polymerization initiator, trihaloalkyl compound and sensitizing dye are not particularly limited, but are preferably 0.1 to 20 parts by mass, preferably 3 to 12 parts by mass in the photosensitive composition of the photosensitive layer. is there. The mixing ratio of the photopolymerization initiator, the trihaloalkyl compound and the sensitizing dye is 30 to 55 parts by mass based on the total amount of the three, and the ratio of the trihaloalkyl compound is 3 to 15 parts by mass. Parts, the ratio of the sensitizing dye is 40 to 67 parts by mass.
[0039]
Examples of the polymer binder of the present invention include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenolic resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellac, and other natural materials. Resin or the like can be used. Further, two or more of these may be used in combination.
[0040]
Preferably, a vinyl copolymer obtained by copolymerizing an acrylic monomer is preferred. Further, the copolymer composition of the polymer binder is preferably a copolymer of (a) a carboxyl group-containing monomer, (b) an alkyl methacrylate, or an alkyl acrylate.
[0041]
Specific examples of the carboxyl group-containing monomer include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, and itaconic anhydride. In addition, a carboxylic acid such as a half ester of phthalic acid and 2-hydroxymethacrylate is also preferable.
[0042]
Specific examples of alkyl methacrylate and alkyl acrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate , Decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, acrylic In addition to unsubstituted alkyl esters such as decyl acrylate, undecyl acrylate and dodecyl acrylate, cyclic alkyl esters such as cyclohexyl methacrylate and cyclohexyl acrylate, Substituted alkyl esters such as benzyl methacrylate, 2-chloroethyl methacrylate, N, N-dimethylaminoethyl methacrylate, glycidyl methacrylate, benzyl acrylate, 2-chloroethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate Are also mentioned.
[0043]
Further, in the polymer binder of the present invention, monomers and the like described in the following 1) to 14) can be used as other copolymerized monomers.
1) Monomers having an aromatic hydroxyl group, for example, o- (or p-, m-) hydroxystyrene, o- (or p-, m-) hydroxyphenyl acrylate and the like.
2) Monomers having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N-methylol acrylamide, N-methylol methacrylamide, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 5-hydroxypentyl methacrylate , 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, N- (2-hydroxyethyl) acrylamide, N- (2-hydroxyethyl) methacrylamide, hydroxyethyl vinyl ether and the like.
3) Monomers having an aminosulfonyl group, for example, m- (or p-) aminosulfonylphenyl methacrylate, m- (or p-) aminosulfonylphenyl acrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p -Aminosulfonylphenyl) acrylamide and the like.
4) Monomers having a sulfonamide group, for example, N- (p-toluenesulfonyl) acrylamide, N- (p-toluenesulfonyl) methacrylamide and the like.
5) Acrylamide or methacrylamides such as acrylamide, methacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N- (4-nitrophenyl) acrylamide, N-ethyl-N- Phenylacrylamide, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide and the like.
6) Monomers containing an alkyl fluoride group, for example, trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octafluoropentyl acrylate, octafluoropentyl methacrylate, heptadecafluorodecyl methacrylate, N- Butyl-N- (2-acryloxyethyl) heptadecafluorooctylsulfonamide and the like.
7) Vinyl ethers, for example, ethyl vinyl ether, 2-chloroethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether and the like.
8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate.
9) Styrenes, for example, styrene, methylstyrene, chloromethylstyrene and the like.
10) Vinyl ketones, for example, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone and the like.
11) Olefins, for example, ethylene, propylene, i-butylene, butadiene, isoprene and the like.
12) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine and the like.
13) Monomers having a cyano group, for example, acrylonitrile, methacrylonitrile, 2-pentenenitrile, 2-methyl-3-butenenitrile, 2-cyanoethylacrylate, o- (or m-, p-) cyanostyrene and the like.
14) Monomers having an amino group, for example, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, polybutadiene urethane acrylate, N, N-dimethylaminopropyl acrylamide, N, N N-dimethylacrylamide, acryloylmorpholine, Ni-propylacrylamide, N, N-diethylacrylamide and the like.
[0044]
Further, other monomers copolymerizable with these monomers may be copolymerized.
The vinyl polymer can be produced by ordinary solution polymerization. It can also be produced by bulk polymerization or suspension polymerization. Examples of the polymerization initiator include, but are not particularly limited to, azobis-based radical generators such as 2,2'-azobisisobutyronitrile (AIBN) and 2,2'-azobis (2-methylbutyroyl). Nitrile) and the like. The amount of the polymerization initiator to be used is generally 0.05 to 10.0 parts by mass (preferably 0.1 to 5 parts by mass) based on 100 parts by mass of the whole monomers used to form the copolymer. Part). Examples of the solvent used for performing the solution polymerization include ketone, ester, and aromatic organic solvents, among which toluene, ethyl acetate, benzene, methyl cellosolve, ethyl cellosolve, acetone, and methyl ethyl ketone. In general, a good solvent of an acrylic polymer is mentioned, and among them, a solvent having a boiling point of 60 to 120 ° C is preferable. In the case of solution polymerization, the above-mentioned solvent is used, and the reaction is usually carried out at a temperature of 40 to 120 ° C (preferably 60 to 110 ° C) and a reaction time of usually 3 to 10 hours (preferably 5 to 8 hours). it can. After completion of the reaction, the solvent is removed to obtain a copolymer. Further, a double bond introduction reaction described later can also be carried out without removing the solvent.
[0045]
The molecular weight of the resulting copolymer can be adjusted by adjusting the solvent used and the reaction temperature. The solvent used for obtaining the copolymer having the desired molecular weight, the reaction temperature, and the like can be appropriately determined depending on the monomer used. Further, the molecular weight of the obtained copolymer can also be adjusted by mixing a specific solvent with the above solvent. Examples of such a solvent include mercaptans (eg, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, etc.), and carbon tetrachlorides (eg, carbon tetrachloride, butyl chloride, propylene chloride) Etc.). The mixing ratio of these solvents to the solvent used in the above reaction can be appropriately determined depending on the monomers used in the reaction, the solvent, the reaction conditions and the like.
[0046]
Further, the polymer binder of the present invention is preferably a vinyl polymer having a carboxyl group and a polymerizable double bond in a side chain. For example, an unsaturated bond-containing vinyl copolymer obtained by performing an addition reaction of a compound having a (meth) acryloyl group and an epoxy group in the molecule to a carboxyl group present in the molecule of the vinyl copolymer. Are also preferred as the polymeric binder. Specific examples of the compound containing both an unsaturated bond and an epoxy group in the molecule include glycidyl acrylate, glycidyl methacrylate, and an epoxy group-containing unsaturated compound described in JP-A-11-271969. Further, an unsaturated bond-containing vinyl copolymer obtained by subjecting a hydroxyl group present in the molecule of the vinyl polymer to an addition reaction of a compound having a (meth) acryloyl group and an isocyanate group in the molecule is also high. Preferred as a molecular binder. Compounds having both an unsaturated bond and an isocyanate group in the molecule include vinyl isocyanate, (meth) acrylic isocyanate, 2- (meth) acryloyloxyethyl isocyanate, m- or p-isopropenyl-α, α'-dimethylbenzyl Isocyanates are preferred, and examples include (meth) acrylic isocyanate and 2- (meth) acryloyloxyethyl isocyanate.
[0047]
A known method can be used to add a compound having a (meth) acryloyl group and an epoxy group in the molecule to a carboxyl group present in the molecule of the vinyl copolymer. For example, the reaction is performed at a reaction temperature of 20 to 100 ° C., preferably 40 to 80 ° C., particularly preferably at the boiling point of the solvent used (under reflux), and the reaction time is 2 to 10 hours, preferably 3 to 6 hours. Can be. Examples of the solvent used include those used in the polymerization reaction of the vinyl copolymer. After the polymerization reaction, the solvent can be used as it is for the introduction reaction of the alicyclic epoxy group-containing unsaturated compound without removing the solvent. The reaction can be carried out in the presence of a catalyst and a polymerization inhibitor, if necessary. Here, the catalyst is preferably an amine-based or ammonium chloride-based material. Specifically, examples of the amine-based material include triethylamine, tributylamine, dimethylaminoethanol, diethylaminoethanol, methylamine, ethylamine, and n-propylamine. Isopropylamine, 3-methoxypropylamine, butylamine, allylamine, hexylamine, 2-ethylhexylamine, benzylamine and the like, and the ammonium chloride-based substance includes triethylbenzylammonium chloride. When these are used as catalysts, they may be added in the range of 0.01 to 20.0% by mass based on the alicyclic epoxy group-containing unsaturated compound used. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroquinone, 2-methylhydroquinone, and 2-t-butylhydroquinone. The amount is 0.01 to 5.0% by mass based on the alicyclic epoxy group-containing unsaturated compound used. The progress of the reaction may be measured by measuring the acid value of the reaction system and stopping the reaction when the desired acid value is reached.
[0048]
A known method can be used to add a compound having a (meth) acryloyl group and an isocyanate group in the molecule to a hydroxyl group present in the molecule of the vinyl polymer. For example, the reaction temperature is usually 20 to 100 ° C., preferably 40 to 80 ° C., particularly preferably at the boiling point of the solvent to be used (under reflux), and the reaction time is usually 2 to 10 hours, preferably 3 to 6 hours. It can be carried out. Examples of the solvent to be used include a solvent used in the polymerization reaction of the polymer copolymer. After the polymerization reaction, the solvent can be used as it is for the introduction reaction of the isocyanate group-containing unsaturated compound without removing the solvent. The reaction can be carried out in the presence of a catalyst and a polymerization inhibitor, if necessary. Here, the catalyst is preferably a tin-based or amine-based substance, and specific examples include dibutyltin laurate and triethylamine. The catalyst is preferably added in the range of 0.01 to 20.0% by mass based on the compound having a double bond to be used. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroquinone 2-methylhydroquinone, and 2-t-butylhydroquinone. The used amount is usually 0.01 to 5.0% by mass based on the isocyanate group-containing unsaturated compound used. The progress of the reaction may be determined by determining the presence or absence of an isocyanato group in the reaction system by infrared absorption spectrum (IR), and stopping the reaction when the absorption disappears.
[0049]
The above-mentioned vinyl polymer having a carboxyl group and a polymerizable double bond in the side chain used in the present invention is preferably 50 to 100% by mass, and more preferably 100% by mass in the total polymer binder. More preferred.
[0050]
The content of the polymer binder in the photosensitive composition applied and formed as the photosensitive layer is preferably in the range of 10 to 90% by mass, more preferably in the range of 15 to 70% by mass, and more preferably in the range of 20 to 50% by mass. Is particularly preferable from the viewpoint of sensitivity.
[0051]
The addition-polymerizable ethylenically unsaturated bond-containing monomer used in the photosensitive composition and photosensitive lithographic printing plate material of the present invention is a radically polymerizable monomer containing at least one photo-oxidizable group. The body is preferred. Particularly preferred are addition polymerizable compounds containing at least one photo-oxidizable group and at least one urethane group in the molecule. Suitable photo-oxidizable groups are, in particular, thio groups, thioether groups, ureido groups, amino groups and enol groups which may be members of a heterocycle. Examples of such groups are triethanolamino, triphenylamino, thioureido, imidazolyl, oxazolyl, thiazolyl, acetylacetonyl, N-phenylglycine and ascorbic acid residues. Preferred are addition polymerizable compounds containing a tertiary amino group and a thioether group.
[0052]
Examples of compounds containing a photooxidizable group are described in European Patent Application Publication Nos. 287,818, 353,389 and 364,735. Preferred among the compounds described therein are those which, in addition to the tertiary amino group, also contain ureido and / or urethane groups.
[0053]
The monomers having at least one photo-oxidizable group and at least one urethane group of the present invention include JP-A-63-260909, JP-A-2669849, JP-A-6-35189, and JP-A-6-35189. 2001-125255.
[0054]
Further, in the present invention, a reaction product of a polyhydric alcohol containing a tertiary amino group in the molecule, a diisocyanate compound, and a compound containing an ethylenic double bond capable of addition polymerization with a hydroxyl group in the molecule is used. Is preferred.
[0055]
Here, the polyhydric alcohol containing a tertiary amino group in the molecule includes triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Nn-butyldiethanolamine, N-tert-butyldiethanolamine, N, N-di (hydroxyethyl) aniline, N, N, N ', N'-tetra-2-hydroxypropylethylenediamine, p-tolyldiethanolamine, N, N, N', N'-tetra-2-hydroxy Ethylethylenediamine, N, N-bis (2-hydroxypropyl) aniline, allyldiethanolamine, 3- (dimethylamino) -1,2-propanediol, 3-diethylamino-1,2-propanediol, N, N- Di (n-propyl) amino-2,3-propanediol, N, N-di iso- propyl) amino-2,3-propanediol, 3- (N-methyl--N- benzylamino) -1,2-propanediol - but Le and the like, but are not limited thereto.
[0056]
Examples of the diisocyanate compound include butane-1,4-diisocyanate, hexane-1,6-diisocyanate, 2-methylpentane-1,5-diisocyanate, octane-1,8-diisocyanate, and 1,3-diisocyanatomethyl-cyclohexanone. 2,2,4-trimethylhexane-1,6-diisocyanate, isophorone diisocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene Examples thereof include 2,5-diisocyanate, tolylene-2,6-diisocyanate, 1,3-di (isocyanatomethyl) benzene, and 1,3-bis (1-isocyanato-1-methylethyl) benzene. Limited to Not. Examples of the compound containing an ethylenic double bond capable of addition polymerization with a hydroxyl group in the molecule include the following compounds such as MH-1 to MH-13, but are not limited thereto.
[0057]
Embedded image

[0058]
Preferably, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxypropylene-1,3-dimethacrylate, 2-hydroxypropylene-1-methacrylate-3-acrylate and the like are exemplified.
[0059]
These reactions can be carried out in the same manner as in the method of synthesizing urethane acrylate by the reaction of ordinary diol compounds, diisocyanate compounds, and hydroxyl group-containing acrylate compounds.
[0060]
The addition-polymerizable ethylenically unsaturated bond-containing monomer used in the photosensitive composition and the photosensitive lithographic printing plate material of the present invention is a general radical-polymerizable monomer other than the above, and is generally used for ultraviolet-curable resins. Polyfunctional monomers having a plurality of addition-polymerizable ethylenic double bonds in the molecule used therein and polyfunctional oligomers can be used in combination. Specific compounds include, for example, 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glyceryl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, tetrahydrofurfuryloxyhexyl acrylate Or methacrylates, itaconates, crotonates, and methacrylates, itaconates, crotonates, and maleates in place of these acrylates; furthermore, for example, ethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol Diacrylate, hydroquinone diacrylate, resorcinol diacrylate , Hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, diacrylate of neopentyl glycol hydroxypivalate, diacrylate of neopentyl glycol adipate, ε-caprolactone adduct of neopentyl glycol hydroxypivalate Diacrylate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1,3-dioxane diacrylate, tricyclodecane dimethylol acrylate, tricyclodecane dimethylol acrylate Bifunctional acrylates such as ε-caprolactone adduct, diglycidyl ether diacrylate of 1,6-hexanediol, or these acrylates Methacrylate, itaconic acid ester, crotonic acid ester, maleic acid ester in place of acrylate, itaconate, crotonate, maleate; furthermore, for example, trimethylolpropane triacrylate, ditrimethylolpropanetetraacrylate, trimethylolethanetriacrylate, pentane Erythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ε-caprolactone adduct of dipentaerythritol hexaacrylate, pyrogallol triacrylate, dipentaerythritol tripropionate Acrylate, propionic acid / dipentaerythritol Polyfunctional acrylates such as tetraacrylate, hydroxypivalylaldehyde-modified dimethylolpropane triacrylate, and EO modified products thereof, or methacrylic acid and itaconate in which these acrylates are replaced with methacrylate, itaconate, crotonate, and maleate Crotonates, maleates and the like.
[0061]
Further, a prepolymer can be used in the same manner as described above. Examples of the prepolymer include the compounds described below, and a prepolymer obtained by introducing acrylic acid or methacrylic acid into an oligomer having an appropriate molecular weight and imparting photopolymerizability can also be suitably used. One or more of these prepolymers may be used in combination, or may be used as a mixture with the above-mentioned monomer and / or oligomer.
[0062]
Examples of the prepolymer include adipic acid, trimellitic acid, maleic acid, phthalic acid, terephthalic acid, hymic acid, malonic acid, succinic acid, glutaric acid, itaconic acid, pyromellitic acid, fumaric acid, glutaric acid, pimelic acid, Polybasic acids such as sebacic acid, dodecanoic acid, and tetrahydrophthalic acid, and ethylene glycol, propylene glycol, diethylene glycol, propylene oxide, 1,4-butanediol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, and trimethylol Polyester obtained by introducing (meth) acrylic acid into a polyester obtained by bonding a polyhydric alcohol such as propane, pentaerythritol, sorbitol, 1,6-hexanediol, and 1,2,6-hexanetriol. Acrylates; for example, epoxy acrylates in which (meth) acrylic acid is introduced into an epoxy resin such as bisphenol A / epichlorohydrin / (meth) acrylic acid or phenol novolak / epichlorohydrin / (meth) acrylic acid; for example, ethylene glycol / adipin Acid ・ tolylene diisocyanate ・ 2-hydroxyethyl acrylate, polyethylene glycol ・ tolylene diisocyanate ・ 2-hydroxyethyl acrylate, hydroxyethylphthalyl methacrylate ・ xylene diisocyanate, 1,2-polybutadiene glycol ・ tolylene diisocyanate ・ 2-hydroxyethyl acrylate Of trimethylolpropane / propylene glycol / tolylene diisocyanate / 2-hydroxyethyl acrylate As described above, urethane acrylate in which (meth) acrylic acid is introduced into urethane resin; for example, silicone resin acrylates such as polysiloxane acrylate, polysiloxane / diisocyanate / 2-hydroxyethyl acrylate; and (meth) acryloyl in oil-modified alkyd resin And prepolymers such as alkyd-modified acrylates having introduced groups and spirane resin acrylates.
[0063]
Further, as the monomer according to the present invention used in the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the present invention, phosphazene monomer / triethylene glycol / isocyanuric acid EO (ethylene oxide) -modified diacrylate, isocyanuric acid Having monomers such as EO-modified triacrylate, dimethylol tricyclodecane diacrylate, trimethylolpropane acrylate benzoate, alkylene glycol type acrylic acid-modified / urethane-modified acrylate, and structural units formed from the monomers Oligomerizable oligomers and prepolymers can be mentioned.
[0064]
Further, as the monomer according to the present invention used in the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the present invention, a phosphate compound containing at least one (meth) acryloyl group can be mentioned. The compound is a compound in which at least a part of the hydroxyl group of phosphoric acid is esterified, and is not particularly limited as long as it has a (meth) acryloyl group.
[0065]
In addition, JP-A-58-212994, JP-A-61-6649, JP-A-62-46688, JP-A-62-48589, JP-A-62-173295, JP-A-62-187092, and JP-A-63-187092. Compounds described in JP-A-67189, JP-A-1-244891 and the like can be mentioned. 286-p. 294, “UV / EB curing handbook (raw material)”, Polymer Publishing Association, p. The compounds described in 11 to 65 and the like can also be suitably used in the present invention. Of these, compounds having two or more acrylic or methacrylic groups in the molecule are preferred in the present invention, and those having a molecular weight of 10,000 or less, more preferably 5,000 or less are preferred.
[0066]
In the photosensitive lithographic printing plate material of the present invention, the monomer or other monomer according to the present invention described above is used in an amount of 1.0 to 80.0% by mass in the photosensitive composition of the photosensitive layer. It is preferably contained, more preferably in the range of 3.0 to 70.0% by mass.
[0067]
The coating composition for the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the present invention contains, in addition to the above-mentioned components, an ethylenically unsaturated diamine which can be polymerized during the production or storage of the photosensitive lithographic printing plate material. In order to prevent unnecessary polymerization of the heavy bond monomer, a hindered phenol compound, a hindered amine compound and other polymerization inhibitors may be added.
[0068]
Examples of hindered phenol compounds include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4 '-Butylidenebis (3-methyl-6-t-butylphenol), tetrakis- [methylene-3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3 '-Bis- (4'-hydroxy-3'-tert-butylphenyl) butyric acid] glycol ester, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl)- 4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylfe Acrylate and the like, and preferably 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate having a (meth) acrylate group, 2- [ 1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate.
[0069]
Examples of the hindered amine compound include bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-t-butyl-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2, 2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3 8-Triazaspiro [4.5] decane-2,4-dione and the like.
[0070]
Other polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol). And hindered amines such as 2,2'-methylenebis (4-methyl-6-t-butylphenol), cerium N-nitrosophenylhydroxylamine, and 2,2,6,6-tetramethylpiperidine derivatives. Can be
[0071]
The addition amount of the polymerization inhibitor is preferably from about 0.01% to about 5% based on the total solid content of the composition. Also, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition by oxygen, or may be unevenly distributed on the surface of the photosensitive layer in a drying process after coating. Good. The addition amount of the higher fatty acid derivative is preferably about 0.5% to about 10% of the whole composition.
[0072]
In the coating composition for the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the present invention, in addition to the above-described components, a coloring agent may be used. Can be suitably used. For example, those described in the revised new edition “Pigment Handbook”, edited by the Japan Pigment Technical Association (Seibundo Shinkosha), Color Index Handbook, and the like can be mentioned.
[0073]
Examples of the type of the pigment include a black pigment, a yellow pigment, a red pigment, a brown pigment, a violet pigment, a blue pigment, a green pigment, a fluorescent pigment, and a metal powder pigment. Specifically, inorganic pigments (titanium dioxide, carbon black, graphite, zinc oxide, Prussian blue, cadmium sulfide, iron oxide, and chromates of lead, zinc, barium, and calcium, etc.) and organic pigments (azo, thioindigo, etc.) , Anthraquinone, anthranthrone, and triphenedioxazine pigments, vat dye pigments, phthalocyanine pigments and derivatives thereof, and quinacridone pigments.
[0074]
Among these, it is preferable to select and use a pigment that does not substantially absorb in the absorption wavelength region of the spectral sensitizing dye corresponding to the exposure laser to be used, and in this case, an integrating sphere at the laser wavelength to be used is used. The reflection and absorption of the pigment used is preferably 0.05 or less. The amount of the pigment is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, based on the solid content of the composition.
[0075]
Further, a plasticizer can be contained in order to improve the adhesiveness to the support. As the plasticizer, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, didodecyl phthalate, diisodecyl phthalate, butyl benzyl phthalate, diisononyl phthalate, ethyl phthalyl ethyl Glycol, dimethyl isophthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin and the like can be mentioned. The amount of the plasticizer added is preferably about 0 to 3% by mass, more preferably 0.1 to 2% by mass, based on the total solid content of the coating composition.
[0076]
Further, the coating composition may contain a surfactant as a coating improver as long as the performance of the present invention is not impaired. Among them, preferred are fluorine-based surfactants.
[0077]
Further, in order to improve the physical properties of the cured film, additives such as an inorganic filler and a plasticizer such as dioctyl phthalate, dimethyl phthalate and tricresyl phosphate may be added. These addition amounts are preferably 10% or less of the total solid content of the coating composition.
[0078]
Examples of the solvent used for preparing the coating composition for the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the present invention include alcohols: sec-butanol, isobutanol, n-hexanol, benzyl alcohol, diethylene glycol. Ethers: propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, etc .; ketones, aldehydes: diacetone alcohol, cyclohexanone, Preferred examples include methylcyclohexanone and the like; esters: ethyl lactate, butyl lactate, diethyl oxalate, methyl benzoate and the like.
[0079]
The prepared coating composition (photosensitive layer coating solution) is applied on a support by a conventionally known method and dried to prepare a photosensitive lithographic printing plate material. Examples of the application method of the coating liquid include an air doctor coater method, a blade coater method, a wire bar method, a knife coater method, a dip coater method, a reverse roll coater method, a gravure coater method, a cast coating method, a curtain coater method, an extrusion coater method, and the like. Can be mentioned.
[0080]
The drying temperature of the photosensitive layer is preferably in the range of 60 to 160C, more preferably 80 to 140C, and particularly preferably 90 to 120C. If the temperature is lower than 60 ° C., sufficient printing durability cannot be obtained. On the other hand, if the temperature is higher than 160 ° C., not only Marangoni occurs but also fogging of the non-image area occurs.
[0081]
A protective layer is preferably provided on the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate material of the invention. The protective layer (oxygen blocking layer) preferably has a high solubility in a developer described later (generally, an aqueous alkaline solution).
[0082]
The material constituting the protective layer is preferably polyvinyl alcohol, polysaccharide, polyvinylpyrrolidone, polyethylene glycol, gelatin, glue, casein, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, hydroxyethyl starch, gum arabic, saccharose octaacetate, alginic acid Examples include ammonium, sodium alginate, polyvinylamine, polyethylene oxide, polystyrenesulfonic acid, polyacrylic acid, and water-soluble polyamide. These compounds can be used alone or in combination of two or more kinds as a protective layer coating composition. Particularly preferred compounds include polyvinyl alcohol.
[0083]
To prepare the protective layer coating composition, the above-mentioned materials can be dissolved in an appropriate solvent to form a coating solution, and this coating solution is coated on the photopolymerizable photosensitive layer according to the present invention, and dried. To form a protective layer. The thickness of the protective layer is preferably from 0.1 to 5.0 μm, particularly preferably from 0.5 to 3.0 μm. The protective layer may further contain a surfactant, a matting agent, and the like, if necessary.
[0084]
As the coating method of the protective layer, the known coating methods mentioned in the coating of the photosensitive layer can be suitably used. The drying temperature of the protective layer is preferably lower than the drying temperature of the photosensitive layer, and the difference from the drying temperature of the photosensitive layer is preferably at least 10 ° C, more preferably at least 20 ° C, and the upper limit is at most about 50 ° C. .
[0085]
Further, the drying temperature of the protective layer is preferably lower than the glass transition temperature (Tg) of the binder contained in the photosensitive layer. The difference between the drying temperature of the protective layer and the glass transition temperature (Tg) of the binder contained in the photosensitive layer is preferably at least 20 ° C, more preferably at least 40 ° C, and the upper limit is at most about 60 ° C.
[0086]
As the support that can be used for the photosensitive lithographic printing plate material of the present invention, an aluminum plate is preferably used. In this case, a pure aluminum plate, an aluminum alloy plate, or the like may be used.
[0087]
As the aluminum alloy of the support, various materials can be used, for example, an alloy of aluminum with a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, or iron is used. Aluminum plates manufactured by various rolling methods can be used. Also, a recycled aluminum plate obtained by rolling a recycled aluminum ingot, such as a scrap material and a recycled material, which has become popular in recent years, can be used.
[0088]
The photosensitive lithographic printing plate material of the present invention and the support that can be used in the image forming method of the present invention are subjected to a degreasing treatment to remove rolling oil on the surface prior to roughening (graining treatment). Is preferred. Examples of the degreasing treatment include a degreasing treatment using a solvent such as trichlene and thinner, and an emulsion degreasing treatment using an emulsion such as kesilon and triethanol. For the degreasing treatment, an aqueous solution of an alkali such as caustic soda can be used. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide films that cannot be removed only by the above degreasing treatment can be removed. If an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is formed on the surface of the support. Preferably, a treatment is applied.
[0089]
Examples of the method of surface roughening include a mechanical method and a method of etching by electrolysis. In one embodiment of the present invention, the method of surface roughening is not particularly limited, but the surface roughness Ra is 0.4 to 0.8 μm. In one embodiment of the present invention, the surface is roughened by alternating current electrolysis in an acidic electrolyte mainly containing hydrochloric acid.
[0090]
The mechanical surface roughening method is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The surface roughening by the brush polishing method is performed, for example, by rotating a rotating brush using brush bristles having a diameter of 0.2 to 0.8 mm, and applying, for example, particles of volcanic ash having a particle size of 10 to 100 μm to water on the support surface. It can be performed by pressing a brush while supplying a uniformly dispersed slurry. For surface roughening by honing polishing, for example, particles of volcanic ash having a particle size of 10 to 100 μm are uniformly dispersed in water, pressure is applied from a nozzle to be ejected, and the surface is made to impinge obliquely on the support surface to perform surface roughening. Can be. Further, for example, abrasive particles having a particle size of 10 to 100 μm are formed on the surface of the support at an interval of 100 to 200 μm by 2.5 × 10 ³ -10 × 10 ³ Pieces / cm ² The sheets can be roughened by laminating the coated sheets so that the sheets are present at a density of 1 and transferring the rough surface pattern of the sheet by applying pressure.
[0091]
After the surface is roughened by the above-mentioned mechanical surface roughening method, it is preferable to immerse the substrate in an aqueous solution of an acid or an alkali in order to remove the abrasive, the formed aluminum debris, and the like that have penetrated the surface of the support (hereinafter, desmutted). Process). As the acid, for example, sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid and the like are used, and as the base, for example, sodium hydroxide, potassium hydroxide and the like are used. Among these, it is preferable to use an aqueous alkali solution such as sodium hydroxide. The dissolution amount of aluminum on the surface is 0.5 to 5 g / m ² Is preferred. After performing the immersion treatment with an alkaline aqueous solution, it is preferable to immerse in an acid such as phosphoric acid, nitric acid, sulfuric acid, and chromic acid or a mixed acid thereof to perform a neutralization treatment.
[0092]
Although the electrochemical surface roughening method is not particularly limited, a method in which the surface is electrochemically roughened with an alternating current in an acidic electrolytic solution is preferable. As the acidic electrolytic solution, an acidic electrolytic solution usually used for an electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolytic solution is preferably used. As the electrochemical surface roughening method, for example, the methods described in JP-B-48-28123, British Patent No. 896,563, and JP-A-53-67507 can be used. This surface roughening method can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. Current density is 10-200 A / dm ² Can be used, but 20 to 150 A / dm ² It is preferable to select from the range. Electricity is 100-5000 c / dm ² Can be used, but 100 to 2500 c / dm ² It is preferable to select from the range. The temperature for performing the surface roughening method may be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C.
[0093]
In the case where electrochemical surface roughening is performed using a nitric acid-based electrolyte as the electrolyte, it can be generally performed by applying a voltage in the range of 1 to 50 volts, but is selected from the range of 10 to 30 volts. Is preferred. Current density is 10-200 A / dm ² Can be used, but 20 to 100 A / dm ² It is preferable to select from the range. Electricity is 100-5000 c / dm ² Can be used, but 100 to 2500 c / dm ² It is preferable to select from the range. The temperature at which the electrochemical surface roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The nitric acid concentration in the electrolytic solution is preferably from 0.1 to 5% by mass. If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.
[0094]
When a hydrochloric acid-based electrolyte is used as the electrolyte, it can be generally applied by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 2 to 30 volts. Current density is 10-200 A / dm ² Can be used, but 20 to 150 A / dm ² It is preferable to select from the range. Electricity is 100-5000 c / dm ² Can be used, but is preferably 100 to 2500 c / dm. ² , And 200 to 2500 c / dm ² It is more preferable to select from the range. The temperature at which the electrochemical surface roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of hydrochloric acid in the electrolyte is preferably 0.1 to 5% by mass. If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.
[0095]
After the surface is roughened by the above-mentioned electrochemical surface roughening method, it is preferable to immerse in an aqueous solution of an acid or an alkali to remove aluminum dust and the like on the surface (desmut treatment). As the acid, for example, sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid and the like are used, and as the base, for example, sodium hydroxide, potassium hydroxide and the like are used. Among these, it is preferable to use an aqueous alkali solution. The dissolution amount of aluminum on the surface is 0.5 to 5 g / m ² Is preferred. Further, it is preferable that after immersion treatment with an aqueous alkali solution, immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof to perform neutralization treatment.
[0096]
The mechanical surface roughening method and the electrochemical surface roughening method may be used alone for surface roughening, or may be performed by performing an electrochemical surface roughening method after the mechanical surface roughening method. It may be surfaced.
[0097]
50 to 1100 irregularities / μm having an average interval or an average diameter of 30 to 150 nm according to the present invention. ² Is not formed by the mechanical surface roughening method or the AC electrolytic surface roughening method using a nitric acid-based electrolytic solution. In that case, it is necessary to perform a sealing treatment after the anodizing treatment.
[0098]
On the other hand, in the AC electrolytic surface roughening method using a hydrochloric acid-based electrolyte, the fine rough surface of the present invention is formed, but the fine rough surface may be dissolved simultaneously with the aluminum dust on the surface due to the desmutting treatment. In that case, it is necessary to perform a sealing treatment after the anodizing treatment. Further, the dissolution amount of aluminum on the surface by the desmut treatment is 0.5 to 1.5 g / m. ² By doing so, the fine rough surface is maintained without being dissolved.
[0099]
Subsequent to the roughening treatment, an anodic oxidation treatment is performed. The method of the anodic oxidation treatment that can be used in the present invention is not particularly limited, and a known method can be used. By performing the anodic oxidation treatment, an oxide film is formed on the support. In the anodic oxidation treatment, an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% is used as an electrolytic solution, and the current density is 1 to 50 A / dm. ² A method of electrolysis at high current density in sulfuric acid described in U.S. Pat. No. 1,412,768, and a method of electrolysis at high current density described in U.S. Pat. No. 3,511,661 are also used. And a method using a solution containing one or more of chromic acid, oxalic acid, malonic acid, and the like. The formed anodized coating amount is 1 to 50 mg / dm. ² Is suitable, and preferably 10 to 40 mg / dm. ² It is. The anodic oxidation coating amount is obtained, for example, by immersing an aluminum plate in a chromic acid phosphoric acid solution (prepared by dissolving 35 g of a 85% phosphoric acid solution and 20 g of chromium (IV) oxide in 1 L of water) to dissolve the oxide film, It can be determined by measuring the change in mass before and after dissolving the coating on the plate.
[0100]
The support subjected to the anodizing treatment may be subjected to a sealing treatment as required. These sealing treatments can be performed using a known method such as hot water treatment, boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.
[0101]
In the mechanical surface roughening method or the AC electrolytic surface roughening method using a nitric acid-based electrolyte, the number of uneven portions having an average interval or an average diameter of 30 to 150 nm of the present invention is 50 to 1100 / μm. ² Since the fine rough surface is not formed, it must be formed by a sealing treatment. In that case, hot water treatment or ammonium acetate treatment is preferred. In the case of hot water treatment, a desired fine rough surface can be obtained by combining the conditions at a temperature of 70 to 97 ° C. and a treatment time of 5 to 180 seconds. Also, by adjusting the pH to 7 to 9.5 with ammonium acetate, a desired fine rough surface can be obtained in a shorter time.
[0102]
On the other hand, in the AC electrolytic surface roughening method using a hydrochloric acid-based electrolyte, the fine rough surface of the present invention is formed, but when the fine rough surface is also dissolved by the desmutting treatment, the hot water treatment or ammonium acetate treatment Can be reformed. Further, a fine structure may be formed by a combination of desmutting treatment conditions and hot water treatment or ammonium acetate treatment.
[0103]
Furthermore, in the present invention, it is preferable to perform a hydrophilization treatment after performing these treatments. Although the hydrophilic treatment is not particularly limited, a water-soluble resin such as polyvinylphosphonic acid, a polymer and a copolymer having a sulfonic acid group in a side chain, polyacrylic acid, a water-soluble metal salt (for example, zinc borate) or A primer coated with a yellow dye, an amine salt or the like can be used. Further, a sol-gel treated substrate having a functional group capable of causing an addition reaction by a radical covalently bonded as disclosed in JP-A-5-304358 is also used. It is preferable that the surface of the support is hydrophilized with polyvinylphosphonic acid. The treatment is not limited to a coating method, a spray method, a dip method, and the like, but a dip method is preferable for reducing the cost of equipment. In the case of the dip method, it is preferable to treat polyvinyl phosphonic acid with a 0.05 to 3% aqueous solution. The processing temperature is preferably 20 to 90 ° C., and the processing time is preferably 10 to 180 seconds. After the treatment, it is preferable to perform a squeegee treatment or a water washing treatment in order to remove excessively laminated polyvinylphosphonic acid. Further, a drying treatment is preferably performed. The drying temperature is preferably from 20 to 95C.
[0104]
In the present invention, exposure is performed using a laser light source in a range of 350 nm to 450 nm. As the available laser light source having a wavelength of 350 to 450 nm, the following can be used. As a gas laser, an Ar ion laser (364 nm, 351 nm), a Kr ion laser (356 nm, 351 nm), a He-Cd laser (441 nm), and as a solid laser, a combination of Nd: YAG (YVO4) and SHG crystal × 2 times ( 355 nm), a combination of Cr: LiSAF and SHG crystal (430 nm), KNbO as a semiconductor laser system ₃ , A ring resonator (430 nm), a combination of a waveguide type wavelength conversion element and an AlGaAs or InGaAs semiconductor (380 nm to 450 nm), a combination of a waveguide type wavelength conversion element and an AlGaInP or AlGaAs semiconductor (300 nm to 350 nm), or an AlGaInN ( 350 nm to 450 nm) and N as a pulse laser ₂ Laser (337 nm, pulse 0.1 to 10 mJ), XeF (351 nm, pulse 10 to 250 mJ) and the like can be mentioned. Among them, an AlGaInN semiconductor laser (commercially available InGaN semiconductor laser 400 to 410 nm) is particularly preferable in terms of wavelength characteristics and cost.
[0105]
Laser scanning methods include cylinder outer surface scanning, cylinder inner surface scanning, and plane scanning. In the cylindrical outer surface scanning, laser exposure is performed while rotating a drum around which a recording material is wound around the outer surface, and rotation of the drum is defined as main scanning and movement of laser light is defined as sub-scanning. In the cylindrical inner surface scanning, a recording material is fixed on the inner surface of the drum, a laser beam is irradiated from the inside, and a main scan is performed in the circumferential direction by rotating a part or all of the optical system, and a part of the optical system Sub-scanning is performed in the axial direction by moving the whole linearly in parallel to the axis of the drum. In the planar scanning, the main scanning of the laser beam is performed by combining a polygon mirror or a galvanometer mirror with an fθ lens or the like, and the sub-scanning is performed by moving the recording medium. The scanning of the outer surface of the cylinder and the scanning of the inner surface of the cylinder are easier to improve the precision of the optical system, and are suitable for high-density recording.
[0106]
In the present invention, after the image exposure, a heat treatment is preferably performed to promote an image forming reaction and to improve sensitivity and printing durability. The method of the heat treatment is not particularly limited, but a non-contact method to the image forming surface is preferable, and a commercially available automatic developing machine equipped with a usual thermostat, a hot-air dryer and a heat treatment unit can be used. The heating is preferably performed at a plate surface temperature of 100 to 130 ° C. If the temperature is too high, there are problems such as fogging of non-image areas, and if the temperature is too low, problems such as insufficient sensitivity and printing durability occur. The heating time is preferably 5 to 60 seconds. If the heating time is too long, there are problems such as fogging of non-image areas, and if the heating time is too short, problems such as insufficient sensitivity and printing durability occur. The time from the end of exposure to the heat treatment is preferably within 300 seconds. If it exceeds 300 seconds, problems such as insufficient sensitivity and printing durability occur.
[0107]
The main component of the developer and replenisher used in the processing method of the present invention may contain at least one compound selected from silicic acid, phosphoric acid, carbonic acid, boric acid, phenols, sugars, oximes and fluorinated alcohols. preferable. It is preferable that the pH of the aqueous alkaline solution is higher than 8.5 and lower than 13.0. More preferably, the pH is 8.5 to 12. Of these, weakly acidic substances such as phenols, saccharides, oximes, and fluorinated alcohols preferably have a dissociation index (pKa) of 10.0 to 13.2. Such acids are selected from those described in IONISATION CONSTANTS OF ORGANIC ACIDS INAQUEOUS SOLUTION published by PergamonPress, and specifically, salicylic acid (13.0) and 3-hydroxy-2-naphthoic acid. (12.84), catechol (12.6), gallic acid (12.4), sulfosalicylic acid (11.7), 3,4-dihydroxysulfonic acid (12.2), 3,4 -Dihydroxybenzoic acid (11.94), 1,2,4-trihydroxybenzene (11.82), hydroquinone (11.56), pyrogallol (11.34), o-cresol (10.94). 33), resorsonol (11.27), p-cresol (10.27), - phenols having a phenolic hydroxyl group, such as cresol (same 10.09) and the like.
[0108]
As the saccharide, a non-reducing sugar that is stable even in an alkali is preferably used. Such non-reducing sugars are saccharides having no free aldehyde group or ketone group and exhibiting no reducibility, trehalose-type oligosaccharides in which reducing groups are bonded to each other, glycosides in which the reducing groups of saccharides are bonded to non-saccharides. It is classified as a sugar alcohol reduced by hydrogenation of a body or a saccharide, and any of them is suitably used in the present invention. Trehalose-type oligosaccharides include saccharose and trehalose, and examples of glycosides include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of sugar alcohols include D, L-arabit, ribit, xylit, D, L-sorbit, D, L-mannit, D, L-idit, D, L-talit, zuricit, and allozurcit. Further, maltitol obtained by hydrogenation of disaccharide and reductant (reduced starch syrup) obtained by hydrogenation of oligosaccharide are preferably used. Furthermore, 2-butanone oxime (12.45), acetoxime (12.42), 1.2-cycloheptanedione oxime (12.3), 2-hydroxybenzaldehyde oxime (12.10), dimethyl Oximes such as glyoxime (11.9), ethanediamide dioxime (11.37) and acetophenone oxime (11.35), for example, 2,2,3,3-tetrafluoropropanol-1 (12 .74), fluorinated alcohols such as trifluoroethanol (12.37) and trichloroethanol (12.24). In addition, aldehydes such as pyridine-2-aldehyde (12.68) and pyridine-4-aldehyde (12.05), adenosine (12.56), inosine (12.5) and guanine (12.68) 12.3), cytosine (12.2), hypoxanthine (12.1), xanthine (11.9) and other nucleic acid-related substances, as well as diethylaminomethylsulfonic acid (12.32) 1-amino-3,3,3-trifluorobenzoic acid (12.29), isopropylidene disulfonic acid (12.10), 1,1-ethylidene diphosphonic acid (11.54), 1,1 -Ethylidene disulfonic acid 1-hydroxy (11.52), benzimidazole (12.86), thiobenzamide (12.8), picoline thioamide (12.55), barbi Include weak acid, such as Le acid (same 12.5). These acidic substances may be used alone or in combination of two or more. Among these acidic substances, preferred are silicic acid, phosphoric acid, carbonic acid, sulfosalicylic acid, salicylic acid and sugar alcohols of non-reducing sugars and saccharose. It is preferable because it has a buffering action and is inexpensive.
[0109]
The ratio of these acidic substances in the developer is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass. Below this range, a sufficient buffering effect cannot be obtained, and at concentrations higher than this range, it is difficult to achieve high concentration and the problem of increased cost arises. As the base to be combined with these acids, sodium hydroxide, ammonium hydroxide, potassium hydroxide and lithium hydroxide are preferably used. These alkali agents are used alone or in combination of two or more. When the pH of the developer is 8.5 or less, the image area of a printing plate obtained from a photosensitive lithographic printing plate developable with such a developer is physically weak, and abrasion during printing is quick and sufficient. Printing durability cannot be obtained. In addition, the image area is chemically weak, and the image of the part wiped with an ink cleaning solvent or a plate cleaner during printing is damaged, and as a result, sufficient chemical resistance cannot be obtained. A developer having a high pH such as a pH exceeding 13.0 has a strong irritating property when it adheres to skin or mucous membranes, and it is not preferable because it requires sufficient care in handling.
[0110]
Others include, for example, potassium silicate, sodium silicate, lithium silicate, ammonium silicate, potassium metasilicate, sodium metasilicate, lithium metasilicate, ammonium metasilicate, tripotassium phosphate, trisodium phosphate, trilithium phosphate, triammonium phosphate, phosphoric acid Dipotassium, disodium phosphate, dilithium phosphate, diammonium phosphate, potassium carbonate, sodium carbonate, lithium carbonate, ammonium carbonate, potassium bicarbonate, sodium bicarbonate, lithium bicarbonate, ammonium bicarbonate, potassium borate, sodium borate, boric acid Lithium, ammonium borate and the like may be mentioned, and may be added in the form of a preformed salt. Also in this case, sodium hydroxide, ammonium hydroxide, potassium and lithium can be added for pH adjustment. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used in combination. Most preferred are potassium silicate and sodium silicate. The concentration of silicate is SiO ₂ It is preferably 1.0 to 3.0% by mass in terms of concentration. In addition, SiO ₂ And the molar ratio of alkali metal M (SiO ₂ / M) is more preferably in the range of 0.25 to 2.
[0111]
The developer referred to in the present invention is not only an unused solution used at the start of development, but also a replenisher for replenishing a replenisher to correct the activity of the solution which is reduced by the processing of the PS plate. Includes retained liquid (so-called running liquid). The replenisher may therefore have a higher activity (alkali concentration) than the developer, so the pH of the replenisher may be above 13.0.
[0112]
To the developer and replenisher used in the present invention, various surfactants and organic solvents can be added as necessary for the purpose of accelerating the developability, dispersing development scum, and enhancing the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Preferred examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, ester polyoxyethylene alkyl phenyl ethers, polyoxyethylene naphthyl ether, polyoxyethylene polystyryl phenyl ethers, and polyoxyethylene polyether. Oxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene Sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxo Ethylene castor oils, polyoxyethylene glycerin fatty acid partial esters, polyoxyethylene-polyoxypropylene block copolymer, polyoxyethylene-polyoxypropylene block copolymer adduct of ethylenediamine, fatty acid diethanolamides, N, N -Bis-2-hydroxyalkylamines, nonionic surfactants such as polyoxyethylenealkylamine, triethanolamine fatty acid ester, and trialkylamine oxide, fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid Acid salts, dialkyl sulfosuccinate salts, linear alkylbenzene sulfonates, branched alkylbenzene sulfonates, alkylnaphthalene sulfonates, polyoxyethylene ants Carboxylic acid, polyoxyethylene naphthyl ether sulfate, alkyl diphenyl ether sulfonate, alkylphenoxy polyoxyethylene propyl sulfonate, polyoxyethylene alkyl sulfophenyl ether salt, polyoxyethylene aryl ether sulfate, N-methyl -N-oleyltaurine sodium salt, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates , Fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styrylphenyl ate Tersulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, partially saponified styrene / maleic anhydride copolymers, olefins / maleic anhydride Partially saponified acid copolymers, anionic surfactants such as naphthalene sulfonate formalin condensates, quaternary ammonium salts such as alkylamine salts, tetrabutylammonium bromide, polyoxyethylene alkylamine salts, polyethylene polyamine Examples include cationic surfactants such as derivatives, amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines. Among the surfactants mentioned above, the term "polyoxyethylene" can be read as a polyoxyalkylene such as polyoxymethylene, polyoxypropylene, or polyoxybutylene, and these surfactants are also included. Further preferred surfactants are fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such a fluorosurfactant include an anionic type such as a perfluoroalkyl carboxylate, a perfluoroalkyl sulfonate, a perfluoroalkyl phosphate, an amphoteric type such as a perfluoroalkyl betaine, and a perfluoroalkyltrimethylammonium salt. Cationic and perfluoroalkylamine oxides, perfluoroalkylethylene oxide adducts, oligomers containing perfluoroalkyl groups and hydrophilic groups, oligomers containing perfluoroalkyl groups and lipophilic groups, perfluoroalkyl groups, hydrophilic groups and lipophilic Non-ionic types such as group-containing oligomers, urethanes containing perfluoroalkyl groups and lipophilic groups are included. The above surfactants can be used alone or in combination of two or more, and are added to the developer in an amount of 0.001 to 10% by mass, more preferably 0.01 to 5% by mass.
[0113]
Various development stabilizers are preferably used in the developer and replenisher used in the present invention. Preferred examples thereof include polyethylene glycol adducts of sugar alcohols described in JP-A-6-282079, tetraalkylammonium salts such as tetrabutylammonium hydroxide, phosphonium salts such as tetrabutylphosphonium bromide, and iodonium such as diphenyliodonium chloride. Salts are mentioned as preferred examples. Further, anionic surfactants or amphoteric surfactants described in JP-A-50-51324, water-soluble cationic polymers described in JP-A-55-95946, and JP-A-56-142528 are described. There are water-soluble amphoteric polyelectrolytes that have been used. Further, an organic boron compound to which an alkylene glycol is added as disclosed in JP-A-59-84241, a polyoxyethylene / polyoxypropylene block polymerization type water-soluble surfactant described in JP-A-60-111246, Polyoxyethylene / polyoxypropylene-substituted alkylenediamine compounds described in JP-A-60-129750, polyethylene glycol having a weight average molecular weight of 300 or more described in JP-A-61-215554, and cations described in JP-A-63-175858 Fluorinated surfactants having a functional group, water-soluble ethylene oxide addition compounds obtained by adding 4 mol or more of ethylene oxide to an acid or alcohol described in JP-A-2-39157, and water-soluble polyalkylene compounds.
[0114]
An organic solvent is further added to the developing solution and the developing replenisher, if necessary. As such an organic solvent, one having a solubility in water of about 10% by mass or less is suitable, and is preferably selected from those having a solubility of 5% by mass or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2-phenoxyethanol, Benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol, N-phenylethanol Examples include amines and N-phenyldiethanolamine. Although the content of the organic solvent is from 0.1 to 5% by mass based on the total mass of the working solution, it is preferably substantially not contained, and particularly preferably not contained at all. Here, “substantially not contained” means that the content is 1% by mass or less.
[0115]
A reducing agent is added to the developer and replenisher used in the present invention as needed. This prevents contamination of the printing plate, and is particularly effective when developing a negative photosensitive lithographic printing plate containing a photosensitive diazonium salt compound. Preferred organic reducing agents include phenolic compounds such as thiosalicylic acid, hydroquinone, methol, methoxyquinone, resorcin, and 2-methylresorcin; and amine compounds such as phenylenediamine and phenylhydrazine. Further preferred inorganic reducing agents include sodium salts, potassium salts, and ammonium salts of inorganic acids such as sulfurous acid, bisulfite, phosphorous acid, hydrogen phosphite, diphosphite, thiosulfate and dithionite. Salts and the like can be mentioned. Among these reducing agents, sulfites are particularly excellent in the stain prevention effect. These reducing agents are contained preferably in the range of 0.05 to 5% by mass with respect to the developing solution at the time of use.
[0116]
An organic carboxylic acid can be further added to the developer and replenisher used in the present invention, if necessary. Preferred organic carboxylic acids are aliphatic and aromatic carboxylic acids having 6 to 20 carbon atoms. Specific examples of the aliphatic carboxylic acid include caproic acid, enantiic acid, caprylic acid, lauric acid, myristic acid, palmitic acid and stearic acid, and particularly preferred are alkanoic acids having 8 to 12 carbon atoms. . Further, unsaturated fatty acids having a double bond in the carbon chain or branched fatty acids may be used. The aromatic carboxylic acid is a compound in which a carboxyl group is substituted on a benzene ring, a naphthalene ring, an anthracene ring, or the like. Specifically, o-chlorobenzoic acid, p-chlorobenzoic acid, o-hydroxybenzoic acid, p- Hydroxybenzoic acid, o-aminobenzoic acid, p-aminobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3, 5-dihydroxybenzoic acid, gallic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-naphthoic acid, 2-naphthoic acid, etc. Naphthoic acid is particularly effective. The above aliphatic and aromatic carboxylic acids are preferably used as a sodium salt, a potassium salt or an ammonium salt in order to enhance water solubility. The content of the organic carboxylic acid in the developer used in the present invention is not particularly limited. However, if the content is less than 0.1% by mass, the effect is not sufficient, and if it is 10% by mass or more, the effect cannot be further improved. In addition, dissolution may be hindered when another additive is used in combination. Therefore, the preferred addition amount is 0.1 to 10% by mass, more preferably 0.5 to 4% by mass, based on the developer used.
[0117]
The following additives can be added to the developer and replenisher used in the present invention, in addition to the above, in order to enhance the developing performance. For example, neutral salts such as NaCl, KCl and KBr described in JP-A-58-75152, and [Co (NH) described in JP-A-59-121336. ₃ )] ₆ Cl ₃ And amphoteric polymer electrolytes such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A-56-142258, and Si, Ti and the like described in JP-A-59-75255. Organic metal surfactants, and organic boron compounds described in JP-A-59-84241 are exemplified. The developer and replenisher used in the present invention may further contain, if necessary, a preservative, a colorant, a thickener, a defoamer, a water softener and the like. Examples of the antifoaming agent include mineral oils, vegetable oils, alcohols, surfactants, and silicones described in JP-A-2-244143. Examples of water softeners include polyphosphoric acid and its sodium, potassium, and ammonium salts, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminedisuccinic acid, methyliminodiacetic acid, β-alaninediacetic acid, triethylenetetraminehexaacetic acid, and hydroxyethylethylenediaminetriacetic acid. Aminopolycarboxylic acids such as acetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexanetetraacetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium, potassium and ammonium salts, aminotri (methylenephosphonic acid), Ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid) Hydroxyethyl ethylene diamine tri (methylene phosphonic acid) and 1-hydroxyethane-1,1-diphosphonic acid and their sodium salts, potassium salts and ammonium salts. The optimum value of such a water softener varies depending on the chelating power, the hardness of the hard water used and the amount of the hard water. %, More preferably in the range of 0.01 to 0.5% by mass. If the addition amount is less than this range, the intended purpose is not sufficiently achieved, and if the addition amount is more than this range, adverse effects on the image area such as color omission appear. The remaining component of the developer and replenisher is water. The conductivity of the obtained developer is more preferably in the range of 5 to 50 mS.
[0118]
It is advantageous from the viewpoint of transportation that the developing solution and the replenishing solution used in the present invention are concentrated solutions having a smaller water content than at the time of use, and are diluted with water at the time of use. In this case, the degree of concentration is appropriately such that each component does not cause separation or precipitation, but it is preferable to add a solubilizing agent if necessary. As such a solubilizing agent, a so-called hydrotroping agent such as toluenesulfonic acid, xylenesulfonic acid and alkali metal salts thereof described in JP-A-6-32081 is preferably used.
[0119]
The water content of the concentrated solution can be further reduced to make it into a solid or paste. In this case, the developer may be once evaporated and then evaporated to dryness.However, it is preferable that the water be not added when mixing a plurality of materials, or the concentrated state is obtained by mixing the materials by adding a small amount of water. Is preferred. Further, this developer concentrate is disclosed in JP-A-51-61837, JP-A-2-10942, JP-A-2-109043, JP-A-3-39735, JP-A-5-142786, and JP-A-6-266602. And granules and tablets can be prepared by a conventionally well-known method described in JP-A-7-13341. The ingredients contained in the solid or paste-like developer concentrate can be the same as those used in ordinary photosensitive lithographic printing plate developers, but those that do not return to the original state even when diluted with water Is preferably not included. For example, silicates become petrochemical when they become low in water content, and become difficult to dissolve in water. Therefore, it is preferable that silicates contain carbonates, phosphates, organic acid salts and the like described later instead of silicates.
[0120]
These concentrates of the developer or solid or paste-like concentrates may be divided into a plurality of parts having different material types and material mixing ratios. These concentrated developer concentrates are preferably diluted with water to a predetermined concentration before development and then used for development. When the developer concentrate or concentrate is used as a development replenisher, it is most preferable to dilute the concentrate with water to a predetermined concentration and then add the diluted solution to the developing solution in use. It is also possible to introduce the developer in use as it is without diluting it to a predetermined concentration. When the developer concentrate is added to a developer in use at a concentration higher than the predetermined concentration or without being diluted to the predetermined concentration, separate water directly into the developer at the same timing or at another timing. May be added.
[0121]
The automatic developing machine used in the present invention is preferably provided with a mechanism for automatically replenishing a required amount of a replenisher to a developing bath, and preferably a mechanism for discharging a developer exceeding a certain amount is provided, Preferably, a mechanism for automatically replenishing a required amount of water to the developing bath is provided, and preferably, a mechanism for detecting pass-through is provided, and preferably, a processing area of the plate based on the pass-through detection is provided. And a mechanism for controlling the replenishing amount and / or replenishing timing of the replenisher and / or water to be replenished, preferably based on the detection of pass-through and / or the estimation of the processing area. A mechanism for controlling the temperature of the developer, preferably a mechanism for detecting the pH and / or conductivity of the developer, and preferably a mechanism for controlling the pH and / or the conductivity of the developer. Or mechanism for controlling the replenishment amount and / or replenishment timing of replenishment solution and / or water attempts to replenish based on conductivity is imparted. When there is a washing step after the developing step, the used washing water can be used as a diluting water for the developing concentrated solution and the concentrated solution of the developing replenisher.
[0122]
The automatic developing machine used in the present invention may have a pre-processing section for immersing the plate in a pre-processing liquid before the developing step. The pre-treatment unit is preferably provided with a mechanism for spraying a pre-treatment liquid on the plate surface, and is preferably provided with a mechanism for controlling the temperature of the pre-treatment liquid to an arbitrary temperature of 25 ° C to 55 ° C, Preferably, a mechanism for rubbing the plate surface with a roller-shaped brush is provided. Water or the like is used as the pretreatment liquid.
[0123]
The plate developed with a developer having such a composition is subjected to post-treatment with washing water, a rinsing solution containing a surfactant or the like, a finisher containing a gum arabic or a starch derivative, or a protective gum solution as a main component. These treatments can be used in various combinations for the post-treatment of the PS plate of the present invention. And less fatigue of the finisher liquid. Further, a countercurrent multistage treatment using a rinsing liquid or a finisher liquid is also a preferred embodiment. These post-processings are generally performed using an automatic developing machine including a developing section and a post-processing section. A method of spraying the post-treatment liquid from a spray nozzle or a method of immersing and conveying the post-treatment liquid in a treatment tank filled with the treatment liquid is used. There is also known a method in which a small amount of washing water is supplied to the plate after washing and washed with water, and the waste liquid is reused as dilution water of the undiluted developer solution. In such automatic processing, processing can be performed while replenishing each processing solution with a replenisher in accordance with the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which treatment is performed with a substantially unused post-treatment liquid can be applied. The lithographic printing plate obtained by such a process is set on an offset printing press and used for printing a large number of sheets.
[0124]
The gum solution is preferably added with an acid or a buffer to remove an alkali component of the developer, and may further contain a hydrophilic polymer compound, a chelating agent, a lubricant, a preservative, a solubilizing agent, and the like. When the gum solution contains a hydrophilic polymer compound, it also has a function as a protective agent for preventing scratches and stains on the plate after development.
[0125]
By adding a surfactant to the gum solution used in the present invention, the surface condition of the coating layer is improved. Surfactants that can be used include anionic surfactants and / or nonionic surfactants. For example, anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, straight-chain alkylbenzenesulfonates, branched-chain alkylbenzenesulfonates, alkylnaphthalene sulfones Acid salts, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, polyoxyethylene aryl ether sulfonates, polyoxyethylene naphthyl ether sulfonates, N-methyl-N-oleyltaurine sodium , N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, nitrated castor oil, sulfated tallow oil, sulfate salts of fatty acid alkyl esters, Alkyl nitrate salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ethers Phosphate salts, polyoxyethylene alkyl phenyl ether phosphate salts, partially saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, naphthalene sulfonate formalin condensates And the like. Among them, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.
[0126]
Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene aryl ethers, polyoxyethylene naphthyl ether, polyoxyethylene polystyryl phenyl ether, and polyoxyethylene polyoxy. Propylene alkyl ether, glycerin fatty acid partial ester, sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol monofatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial Esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylene Sesame oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, triethanolamine fatty acid ester, trialkylamine oxide, etc. Can be Among them, polyoxyethylene alkylphenyl ethers, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used. Further, fluorine-based, silicon-based anion and nonionic surfactants can be used in the same manner. These surfactants can be used in combination of two or more. For example, two or more different types may be used in combination. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable. The amount of the surfactant used is not particularly limited, but is preferably 0.01 to 20% by mass of the post-treatment solution.
[0127]
In the gum solution used in the present invention, a polyhydric alcohol, an alcohol, and an aliphatic hydrocarbon can be used as a lubricant, if necessary, in addition to the above components.
[0128]
For example, among the polyhydric alcohols, preferred specific examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, sorbitol, propyl alcohol, butyl alcohol, pentanol, hexanol, heptanol, Octanol, pendyl alcohol, phenoxyethanol, phenylaminoethyl alcohol, n-hexanol, methylamyl alcohol, 2-ethylbutanol, n-heptanol, 3-heptanol, 2-octanol, 2-ethylhexanol, nonanol, 3,5,5 -Trimethylhexanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol , Heptadecanol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2,4-hexanediol, 1,8-octanediol, 1,9-nonanediol , 1,10-decanediol, glycerin, trimethylolpropane and the like are preferably used. These wetting agents may be used alone or in combination of two or more. Generally, it is preferred that the wetting agent be used in an amount of 1 to 25% by weight.
[0129]
Various hydrophilic polymers can be contained for the purpose of improving the film forming property. As such a hydrophilic polymer, any polymer which can be conventionally used in a gum solution can be suitably used. For example, gum arabic, cellulose derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, polyvinyl alcohol and its derivatives, polyvinylpyrrolidone, polyacrylamide and its copolymers, vinyl methyl ether / maleic anhydride Examples include a polymer, a vinyl acetate / maleic anhydride copolymer, and a styrene / maleic anhydride copolymer.
[0130]
Generally, it is more advantageous to use the gum solution used in the present invention in the acidic range of pH 3 to 6. In order to adjust the pH to 3 to 6, it is generally adjusted by adding a mineral acid, an organic acid or an inorganic salt to the post-treatment liquid. The addition amount is preferably 0.01 to 2% by mass. For example, the mineral acids include nitric acid, sulfuric acid, phosphoric acid, and metaphosphoric acid.
[0131]
Examples of the organic acid include citric acid, acetic acid, oxalic acid, malonic acid, p-toluenesulfonic acid, tartaric acid, malic acid, lactic acid, levulinic acid, phytic acid, and organic phosphonic acid. Further, examples of the inorganic salt include magnesium nitrate, sodium phosphate monobasic, sodium phosphate dibasic, nickel sulfate, sodium hexamethanoate, sodium tripolyphosphate and the like. At least one kind or two or more kinds of mineral acids, organic acids or inorganic salts may be used in combination.
[0132]
A preservative, an antifoaming agent and the like can be added to the gum solution used in the present invention. For example, as a preservative, phenol or a derivative thereof, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benzoisothiazolin-3-one, benztriazole derivative, amidizing anidine derivative, quaternary ammonium salt, pyridine, Derivatives such as quinoline and guanidine, diazines, triazole derivatives, oxazoles, oxazine derivatives and the like can be mentioned. A preferable addition amount is an amount that exerts a stable effect on bacteria, molds, yeasts, and the like, and varies depending on the kind of bacteria, molds, and yeasts. It is preferably in the range of 4% by mass to 4% by mass, and it is preferable to use two or more preservatives in combination so as to be effective against various molds and sterilization. Further, as the defoaming agent, a silicone defoaming agent is preferable. Among them, any of an emulsification dispersion type and a solubilization type can be used. Preferably, the range is 0.01 to 1.0% by mass based on the gum solution at the time of use.
[0133]
Further, a chelate compound may be added. Preferred chelating compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its sodium salt; ethylenediaminedisuccinic acid, its potassium salt Triethylenetetramine hexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt: nitrilotriacetic acid, its sodium salt; 1-hydroxyethane-1,1-diphosphone Acids, potassium salts, sodium salts thereof; organic phosphonic acids or phosphonoalkanetricarboxylic acids such as aminotri (methylene phosphonic acid), potassium salts, sodium salts thereof, etc. It can be mentioned. Organic amine salts are also effective in place of the sodium and potassium salts of the above chelating agents. These chelating agents are selected from those which are stably present in the gum solution composition and do not inhibit printability. The addition amount is suitably 0.001 to 1.0% by mass based on the gum solution at the time of use.
[0134]
In addition to the above components, a sensitizer may be added as necessary. For example, hydrocarbons such as turpentine oil, xylene, toluene, loheptane, solvent naphtha, kerosene, mineral spirit, and a petroleum fraction having a boiling point of about 120 ° C. to about 250 ° C., for example, dibutyl phthalate, dihebutyl phthalate, di-n-octyl Phthalate diester agents such as phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, and butyl benzyl phthalate, for example, dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di ( Aliphatic dibasic acid esters such as 2-ethylhexyl) sebacate and dioctyl sebacate; for example, epoxidized triglycerides such as epoxidized soybean oil; for example, tricresyl phosphate and trioctyl phosphate; Feto, phosphoric acid esters such as tris chloroethyl phosphate, for example, freezing point, such as benzoic acid esters of benzyl benzoate and at 15 ℃ below boiling point at one atmosphere include 300 ° C. or more plasticizers.
[0135]
Furthermore, caproic acid, enanthic acid, caprylic acid, helargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoserin Saturated fatty acids such as acids, cerotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, isovaleric acid, and acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, setreic acid, nilucic acid, and butesidine. Also included are unsaturated fatty acids such as acids, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearic acid, succinic acid, tallic acid, and ricanoic acid. More preferably, it is a fatty acid which is liquid at 50 ° C., more preferably 5 to 25 carbon atoms, most preferably 8 to 21 carbon atoms. These sensitizers can be used alone or in combination of two or more. A preferred range for the amount used is 0.01 to 10% by mass of the gum, and a more preferred range is 0.05 to 5% by mass.
[0136]
The above-mentioned sensitizing agent may be prepared by emulsifying and dispersing a gum and may be contained as an oil phase thereof, or may be solubilized with the aid of a solubilizing agent.
[0137]
In the present invention, the solid concentration of the gum solution is preferably 5 to 30 g / l. The gum film thickness can be controlled by the condition of the squeezing means of the automatic processing machine. In the present invention, the amount of gum applied is 1 to 10 g / m. ² Is preferred. If the gum application amount exceeds 10, the plate surface must be heated to a very high temperature in order to dry in a short time, which is disadvantageous in terms of cost and safety, and the effect of the present invention cannot be sufficiently obtained. 1g / m ² When the ratio is less than the above range, uniform coating becomes difficult, and stable processability cannot be obtained.
[0138]
In the present invention, the time from the end of application of the gum solution to the start of drying is preferably 3 seconds or less. More preferably, it is 2 seconds or less, and the shorter this time is, the more the ink deposition property is improved.
[0139]
In the present invention, the drying time is preferably from 1 to 5 seconds. When the drying time is 5 seconds or longer, the effects of the present invention cannot be obtained. If the drying time is 1 second or less, it is necessary to heat the plate surface to a very high temperature in order to sufficiently dry the photosensitive lithographic printing plate, which is not preferable in terms of safety and cost.
[0140]
In the present invention, as a drying method, a known drying method such as a warm air heater or a far infrared heater can be used.
[0141]
In the drying step, the solvent in the gum solution needs to be dried. Therefore, it is necessary to secure a sufficient drying temperature and heater capacity. The temperature required for drying depends on the components of the gum solution, but in the case of a gum solution in which the solvent is water, the drying temperature is usually preferably 55 ° C. or higher. In many cases, the heater capacity is more important than the drying temperature, and the capacity is preferably 2.6 kW or more in the case of the hot air drying method. The larger the capacity, the better, but preferably 2.6 to 7 kW in terms of cost.
[0142]
In the present invention, the washing liquid used in the washing step before development is usually water, but the following additives can be added as needed.
[0143]
As the chelating agent, a compound that coordinates with a metal ion to form a chelate compound is used. Ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, ethylenediaminedisuccinic acid, its potassium salt, its sodium salt, triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt , Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt, nitriotriacetic acid, its potassium salt, its sodium salt, 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, its sodium salt, aminotri (methylenephosphonic acid) Acid), its potassium salt, its sodium salt, phosphonoalkanetricarboxylic acid, ethylenediaminedisuccinic acid, its potassium salt, its sodium salt and the like. As these chelating agents, those having an organic amine salt instead of the potassium salt and the sodium salt are also effective. The addition amount of the chelating agent is suitably in the range of 0 to 3.0% by mass.
[0144]
As the surfactant, any of anionic, nonionic, cationic and amphoteric surfactants can be used, but anionic or nonionic surfactants are preferred. The type of the preferred surfactant differs depending on the composition of the overcoat layer and the photosensitive layer. Generally, a surfactant which serves as a dissolution accelerator for the material of the overcoat layer and has a low solubility of the photosensitive layer component is preferred.
[0145]
Examples of anionic surfactants include fatty acid salts, avicenates, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylphenoxypolyoxyethylenepropylsulfonates , Polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurate, disodium N-alkyl sulfosuccinate monoamides, petroleum sulfonates, sulfated castor oil, sulfated tallow oil, fatty acid alkyl esters Sulfate, alkyl sulfate, polyoxyethylene alkyl ether sulfate, fatty acid monoglyceride sulfate, polyoxyethylene styrylphenyl Ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, partially saponified styrene-maleic anhydride copolymers, olefin-maleic anhydride copolymers Saponified products, formalin condensates of naphthalenesulfonate and the like.
[0146]
Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid esters, and sorbitan fatty acid partial esters , Pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, ethylene glycol fatty acid esters, polyiglycerin fatty acid partial esters, polyoxyethylene castor oil , Polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-hydroxyalkylamine , Polyoxyethylene alkylamine, triethanolamine fatty acid esters, trialkylamine oxides and the like.
The preferable addition amount of the surfactant is 0 to 10% by mass. Further, an antifoaming agent can be used in combination with the surfactant.
[0147]
Examples of preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, benzotriazole derivatives, amidizing anidine derivatives, quaternary ammonium salts, pyrazine, Derivatives such as quinoline and guanidine, diazines, triazole derivatives, oxazoles, oxazine derivatives and the like can be mentioned.
[0148]
In the cleaning method of the present invention, the temperature of the cleaning solution used for pre-development cleaning is preferably adjusted, and the temperature is preferably in the range of 10 to 60C. As a cleaning method, a known processing liquid supply technique such as spraying, dipping, or coating can be used, and a processing promoting means such as a brush, a squeezing roll, and a submerged shower in dipping can be used as appropriate.
[0149]
In the present invention, the development treatment may be performed immediately after the completion of the pre-development cleaning step, or the development processing may be performed after drying after the pre-development cleaning step. After the development step, known post-treatments such as washing with water, rinsing, and gumming can be performed. The pre-development rinse water used once or more can be reused for the post-development rinse water, rinsing solution and gum solution.
[0150]
The photosensitive lithographic printing plate material of the invention is printed by a printing machine after image formation, but is not particularly limited to a printing machine, printing paper, printing ink, fountain solution, and the like. In recent years, environmental conservation has been called for in the printing industry, and inks that do not use petroleum-based volatile organic compounds (VOCs) have been developed and widely used as printing inks. This is particularly noticeable when the printing ink is used. Examples of environmentally friendly printing inks include soybean oil ink "Naturalis 100" manufactured by Dainippon Ink and Chemicals, VOC zero ink "TK Hi-Echo NV" manufactured by Toyo Ink, and process ink "Soiselbo" manufactured by Tokyo Ink. Can be
[0151]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but embodiments of the present invention are not limited thereto. In the examples, “parts” represents “parts by mass” unless otherwise specified.
[0152]
Example 1
(Synthesis of polymer binder B-1)
In a three-necked flask under a nitrogen stream, methyl methacrylate (125 parts: 1.25 mol), ethyl methacrylate (12 parts: 0.10 mol), methacrylic acid (63 parts: 0.73 mol), cyclohexanone (240 parts), Isopropyl alcohol (160 parts) and α, α′-azobisisobutyronitrile (5 parts) were added and reacted in an oil bath at 80 ° C. for 6 hours in a nitrogen stream to obtain a high molecular polymer. Thereafter, 4 parts of triethylbenzylammonium chloride and glycidyl methacrylate (52 parts: 0.73 mol) were added to the polymer and reacted at a temperature of 25 ° C. for 3 hours to obtain a polymer binder B-1. The weight average molecular weight was about 55,000 (GPC: in terms of polystyrene).
[0153]
(Preparation of support)
A 0.3 mm thick aluminum plate (material 1050, tempered H16) was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., subjected to a 1-minute degreasing treatment, and then washed with water. The degreased aluminum plate was immersed in a 10% hydrochloric acid aqueous solution maintained at 25 ° C. for 1 minute to neutralize, and then washed with water. Next, this aluminum plate was placed in a 1.5% by mass aqueous hydrochloric acid solution at 25 ° C. and a current density of 60 A / dm. ² The electrolytic surface roughening was performed for 30 seconds with an alternating current under the conditions described above. Thereafter, a desmut treatment was performed for 10 seconds in a 1% aqueous sodium hydroxide solution kept at 50 ° C. The surface-roughened aluminum plate subjected to desmut treatment is placed in a 30% sulfuric acid solution at 25 ° C. and a current density of 30 A / dm. ² Anodizing treatment was performed for 30 seconds under the conditions of a voltage of 25 V.
[0154]
(Polyvinyl phosphonic acid treatment)
The above support was dipped in a 0.44% aqueous solution of polyvinyl phosphonic acid at 75 ° C. for 30 seconds, washed with distilled water, and dried with cold air at 25 ° C. to obtain a support A for a photosensitive lithographic printing plate. Got.
[0155]
In the same manner as in the above method, the conditions for electrolytic surface roughening with hydrochloric acid and desmutting conditions were variously changed, and the conditions for sealing treatment in an aqueous solution containing ammonium acetate after the anodizing treatment were changed, and the support for the photosensitive lithographic printing plate was changed. The bodies B to J were obtained. Table 1 shows the manufacturing conditions, the obtained Ra, and the results of the fine rough surface. Electron micrographs of the supports A, D, and G are shown in FIGS.
[0156]
The surface roughness Ra was measured by a non-contact three-dimensional micro surface shape measurement system (WYKO manufactured by Veeco) at a magnification of 40 times. The number of uneven portions having an average interval or an average diameter of the fine rough surface of 30 to 150 nm is determined by using a Hitachi scanning electron microscope S-5000H with a Pt-Pd; 1 nm coating, an acceleration voltage of 5 kV, an inclination angle; The surface was observed and determined at a magnification of 100,000.
[0157]
[Table 1]

[0158]
(Preparation of photosensitive lithographic printing plate materials 1 to 10)
A coating solution of a photopolymerizable photosensitive layer having the following composition was dried at 1.5 g / m 2 on the surface-treated support. ² And dried at 95 ° C. for 1.5 minutes. Thereafter, a coating solution of a protective layer having the following composition was further dried on the photosensitive layer at a rate of 2.0 g / m 2 when dried. ² And dried at 75 ° C. for 1.5 minutes to prepare a photosensitive lithographic printing plate material having a protective layer on the photosensitive layer.
[0159]

[0160]
Embedded image

[0161]
(Image formation)
The photopolymerizable photosensitive lithographic printing plate material thus produced was subjected to 2400 dpi (1 inch by dpi) using a plate setter (Tigercat: a modified product of ECRM) equipped with a laser light source of 408 nm and 30 mW output. That is, image exposure was performed at a resolution of 2.54 cm. Next, before development, a heating unit, a washing unit before removing the protective layer, a developing unit filled with the following developer composition, a washing unit for removing the developing solution attached to the plate surface, a gum solution for protecting the image area ( Developing treatment was performed with a CTP automatic developing machine (PHW23-V: manufactured by Techniggraph) equipped with GW-3: manufactured by Mitsubishi Chemical Co., Ltd., which was diluted two-fold. Thus, planographic printing plate materials 1 to 10 were obtained. At this time, the heating device was set so that the plate surface temperature was 115 ° C. and the plate residence time was 15 seconds. After the exposure was completed, the plate was inserted into the heating unit of the automatic processing machine within 60 seconds.
[0162]
Developer composition (aqueous solution containing the following additives)
Potassium silicate aqueous solution (SiO ₂ : 26%, K ₂ O: 13.5%) 40.0 g / L
Potassium hydroxide 4.0g / L
Ethylenediaminetetraacetic acid 0.5g / L
Polyoxyethylene (13) naphthyl ether sulfonate 20.0 g / L
The volume was made up to 1 L with water. pH was 12.3.
[0163]
(Evaluation of lithographic printing plate)
The photosensitive lithographic printing plate material obtained as described above was evaluated as follows. Table 2 shows the evaluation results.
[0164]
(sensitivity)
A lithographic printing plate is prepared by exposing and developing an image of 175 lines on a photosensitive lithographic printing plate material, and the minimum amount of exposure energy at which no film loss is observed in the 100% image area recorded on the plate surface of the lithographic printing plate Was set as the recording energy and used as an index of sensitivity. The smaller the recording energy, the higher the sensitivity.
[0165]
(Printing durability)
A 175 line image is applied to a photosensitive lithographic printing plate material at 100 μJ / cm. ² The lithographic printing plate prepared by exposing and developing at the exposure amount is coated with a printing machine (DAIYA1F-1: manufactured by Mitsubishi Heavy Industries), coated paper, printing ink (soybean oil ink Naturalis 100: manufactured by Dainippon Ink and Chemicals) and Printing is performed using a dampening solution (H-solution SG-51, concentration: 1.5%, manufactured by Tokyo Ink Co., Ltd.), and the number of printed sheets in which highlight spots are thinned and shadows are entangled is an index indicating printing durability. Shown as The higher the number of prints, the higher the printing durability.
[0166]
(Dirty)
Printing was performed under the same conditions as above, and 2,000 sheets were printed from the start of printing. Thereafter, the plate was left idle for 3 minutes to completely dry the fountain solution on the plate surface. Then, an ink-applying roller was brought into contact with the plate surface five times to apply ink to the entire surface of the plate. The number of prints from the start of printing to the recovery of the stain on the non-image portion from the state of the entire background stain is shown as an indicator of stainability. Those with a small number of recovered sheets indicate good.
[0167]
(Appropriate for plate cleaner)
Under the same printing conditions as above, the printing plate was washed with a sponge for 1 minute with an ultraplate cleaner (manufactured by ABC Chemical Co., Ltd.) for every 500 prints, left for 3 minutes, washed with sponge, and printing was resumed. The same operation was repeated, and the number of times that the ink was not placed on the solid portion was used as an index of suitability for the plate cleaner. The higher the number, the higher the suitability for the plate cleaner.
[0168]
(Dot reproducibility)
A 175-line halftone dot pattern is formed on a photosensitive lithographic printing plate material without linearity correction at 100 μJ / cm. ² With respect to the lithographic printing plate prepared by exposing and developing at the exposure amount, the reproduction range of dot percentage was used as an index of dot reproducibility. The wider the reproduction range from the highlight portion to the shadow portion, the better the dot reproducibility.
[0169]
[Table 2]

[0170]
Table 2 shows that the photosensitive lithographic printing plate materials using the support of the present invention are all excellent in high sensitivity, high printing durability, stain resistance, suitability for plate cleaner, and dot reproducibility.
[0171]
Example 2
A photosensitive lithographic printing plate material was prepared in the same manner as in Example 1 except that the preparation of the support was changed as described below, and the same evaluation was performed.
[0172]
(Preparation of support)
An aluminum plate having a thickness of 0.3 mm (material: 1050, tempered H16) was grained with a No. 8 nylon brush and an 800-mesh pumicestone water suspension, and then thoroughly washed with water. After etching by dipping in 10% sodium hydroxide at 70 ° C. for 60 seconds, washing with running water, and then washing with 20% HNO ₃ And washed with water. Next, this aluminum plate was placed in a 0.7% by mass aqueous hydrochloric acid solution at 25 ° C. and a current density of 50 A / dm. ² Under the conditions described above, the electrolytic surface roughening was performed with an alternating current for 40 seconds. Thereafter, a desmut treatment was performed for 10 seconds in a 0.8% aqueous sodium hydroxide solution kept at 50 ° C. The surface-roughened aluminum plate subjected to desmut treatment is placed in a 30% sulfuric acid solution at 25 ° C. and a current density of 30 A / dm. ² Anodizing treatment was performed for 30 seconds under the conditions of a voltage of 25 V.
[0173]
(Polyvinyl phosphonic acid treatment)
The above support is dipped in a 0.44% aqueous solution of polyvinylphosphonic acid at 75 ° C. for 30 seconds, then washed with distilled water and dried with cold air at 25 ° C. to obtain a support K for a photosensitive lithographic printing plate. Got.
[0174]
In the same manner as in the above method, the conditions for electrolytic surface roughening with hydrochloric acid and desmutting conditions were variously changed, and the conditions for sealing treatment in an aqueous solution containing ammonium acetate after the anodizing treatment were changed, and the support for the photosensitive lithographic printing plate was changed. The bodies L to S were obtained. Table 3 shows the production conditions, the obtained Ra, and the results of the fine rough surface.
[0175]
[Table 3]

[0176]
Table 4 shows the evaluation results.
[0177]
[Table 4]

[0178]
Table 4 shows that the photosensitive lithographic printing plate materials using the support of the present invention are all excellent in high sensitivity, high printing durability, stain resistance, suitability for plate cleaner, and dot reproducibility.
[0179]
Example 3
A photosensitive lithographic printing plate material was prepared in the same manner as in Example 1 except that the preparation of the support was changed as described below, and the same evaluation was performed.
[0180]
(Preparation of support)
A 0.3 mm thick aluminum plate (material 1050, tempered H16) was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., subjected to a 1-minute degreasing treatment, and then washed with water. The degreased aluminum plate was immersed in a 10% hydrochloric acid aqueous solution maintained at 25 ° C. for 1 minute to neutralize, and then washed with water. Next, this aluminum plate was placed in a 1.5% by mass aqueous nitric acid solution at 25 ° C. and a current density of 40 A / dm. ² Under the conditions described above, the electrolytic surface roughening was performed for 20 seconds with an alternating current. Thereafter, a desmutting treatment was performed for 10 seconds in a 1% aqueous sodium hydroxide solution kept at 50 ° C. The surface-roughened aluminum plate subjected to the desmut treatment is placed in a 30% sulfuric acid solution at 25 ° C. and a current density of 30 A / dm. ² Anodizing treatment was performed for 30 seconds under the conditions of a voltage of 25 V. Next, sealing treatment was performed for 10 seconds with a 0.1% aqueous ammonium acetate solution maintained at 85 ° C.
[0181]
(Polyvinyl phosphonic acid treatment)
The above support is dipped in a 0.44% aqueous solution of polyvinylphosphonic acid at 75 ° C. for 30 seconds, then washed with distilled water and dried with cold air at 25 ° C. to obtain a photosensitive lithographic printing plate support T. Got.
[0182]
In the same manner as in the above method, the conditions for electrolytic surface roughening with nitric acid, desmutting conditions, and sealing treatment in an aqueous solution containing ammonium acetate after anodizing treatment were changed to obtain photosensitive lithographic printing plate supports U to Z. Was. Table 5 shows the manufacturing conditions, the obtained Ra, and the results of the fine rough surface.
[0183]
[Table 5]

[0184]
Table 6 shows the evaluation results.
[0185]
[Table 6]

[0186]
Table 6 shows that the photosensitive lithographic printing plate materials using the support of the present invention are all excellent in high sensitivity, high printing durability, stain resistance, suitability for plate cleaner, and dot reproducibility.
[0187]
Example 4
A photosensitive lithographic printing plate material was prepared in the same manner as in Example 1 except that the preparation of the support was changed as described below, and the same evaluation was performed.
[0188]
(Preparation of support)
An aluminum plate having a thickness of 0.3 mm (material: 1050, tempered H16) was grained with a No. 8 nylon brush and an 800-mesh pumicestone water suspension, and then thoroughly washed with water. After etching by dipping in 10% sodium hydroxide at 70 ° C. for 60 seconds, washing with running water, and then washing with 20% HNO ₃ And washed with water. Next, this aluminum plate was placed in a 1.0% by mass aqueous nitric acid solution at 25 ° C. and a current density of 30 A / dm. ² Under the conditions described above, the electrolytic surface roughening was performed for 20 seconds with an alternating current. Thereafter, a desmutting treatment was performed for 10 seconds in a 1% aqueous sodium hydroxide solution kept at 50 ° C. The surface-roughened aluminum plate subjected to the desmut treatment is placed in a 30% sulfuric acid solution at 25 ° C. and a current density of 30 A / dm. ² Anodizing treatment was performed for 30 seconds under the conditions of a voltage of 25 V. Then, sealing treatment was performed for 10 seconds with a 0.12% aqueous ammonium acetate solution kept at 85 ° C.
[0189]
(Polyvinyl phosphonic acid treatment)
The above support is dipped in a 0.44% aqueous solution of polyvinylphosphonic acid at 75 ° C. for 30 seconds, then washed with distilled water and dried with cold air at 25 ° C. to obtain a support AA for a photosensitive lithographic printing plate. Got.
[0190]
In the same manner as in the above method, the conditions for electrolytic surface roughening with nitric acid, desmutting conditions, and sealing treatment in an aqueous solution containing ammonium acetate after anodizing treatment were changed to obtain photosensitive planographic printing plate supports AB to AG. Was. Table 7 shows the manufacturing conditions, the obtained Ra, and the results of the fine rough surface.
[0191]
[Table 7]

[0192]
Table 8 shows the evaluation results.
[0193]
[Table 8]

[0194]
Table 8 shows that the photosensitive lithographic printing plate materials using the support of the present invention are all excellent in high sensitivity, high printing durability, stain resistance, suitability for plate cleaner, and halftone dot reproducibility.
[0195]
【The invention's effect】
According to the present invention, there is provided a photosensitive lithographic printing plate material which is excellent in high sensitivity, high printing durability, stain resistance, plate cleaner suitability, and dot reproducibility, and which is compatible with laser exposure in a 350 nm to 450 nm region, and an image forming method thereof. I was able to.
[Brief description of the drawings]
FIG. 1 is an electron micrograph of a support A.
FIG. 2 is an electron micrograph of a support D.
FIG. 3 is an electron micrograph of a support G.

Claims (7)

A photoinitiator, a polymer binder, an addition-polymerizable ethylenically unsaturated bond-containing monomer, and an absorption maximum between 350 nm and 450 nm In a photosensitive lithographic printing plate material obtained by coating a photosensitive composition containing a sensitizing dye having a surface roughness Ra of the support of 0.4 to 0.8 μm, and an average interval or average A photosensitive lithographic printing plate material, characterized in that the uneven portion having a diameter of 30 to 150 nm has a fine rough surface of 50 to 1100 / μm ² . The photosensitive lithographic printing plate material according to claim 1, wherein the fine rough surface of the support is a rough surface formed by an alternating current electrolytic treatment in an acidic electrolytic solution mainly containing hydrochloric acid. 2. The photosensitive lithographic printing plate material according to claim 1, wherein the fine rough surface of the support is a rough surface formed by a sealing treatment after anodic oxidation. The photosensitive lithographic printing plate material according to any one of claims 1 to 3, wherein the support has been subjected to a hydrophilic treatment before applying the photosensitive composition. The photosensitive lithographic printing plate material according to any one of claims 1 to 4, wherein the photopolymerization initiator is an iron arene complex compound. The photosensitive composition contains a trihaloalkyl compound and an addition-polymerizable ethylenically unsaturated bond-containing monomer containing a photo-oxidizable group, according to any one of claims 1 to 5, The photosensitive lithographic printing plate material as described above. The photosensitive lithographic printing plate material according to any one of claims 1 to 6 is image-exposed by a laser beam having a wavelength of from 350 nm to 450 nm, so that the photosensitive composition layer of the photosensitive lithographic printing plate material is imagewise exposed. An image forming method for a photosensitive lithographic printing plate material, comprising, after curing, removing an unexposed portion of the photosensitive composition layer from a support with an alkali developing solution.

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