JP2004114324A - Lithographic printing plate support and lithographic printing plate original plate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate support, a lithographic printing plate made of which has no development of dotted residual films and is excellent in stain resistance and in plate wear, and a lithographic printing plate original plate using the same. <P>SOLUTION: This lithographic printing plate support is made of an aluminum plate subjected to a roughening treatment including a mechanical roughening treatment and an anodizing treatment. In addition, the aluminum content of the aluminum plate is ≥95 mass% and <99.50 mass%. The surface of the aluminum plate has a grained form obtained by superposing a large wave structure having a mean wavelength of 5-100 μm, a medium wave structure having a mean aperture diameter of 0.5-5 μm and a small wave structure having a mean aperture diameter of 0.01-0.20 μm one upon another. <P>COPYRIGHT: (C)2004,JPO

Description

【０１３２】
上記の各アルミニウム板ＡＬ１〜ＡＬ７に、以下に示す表面処理Ａ〜Ｅを第２表に示す組み合わせで施し、平版印刷版用支持体を得た。
【０１３３】
＜表面処理Ａ＞
表面処理Ａは、以下に示す各種処理を連続的に行うことにより行った。なお、各処理および水洗の後にはニップローラで液切りを行った。
【０１３４】
（ａ）機械的粗面化処理
図１に示したような装置を使って、研磨剤（パミス、平均粒径３０μｍ）と水との懸濁液（比重１．１２）を研磨スラリー液としてアルミニウム板の表面に供給しながら、回転するローラ状ナイロンブラシにより機械的粗面化処理を行った。図１において、１はアルミニウム板、２および４はローラ状ブラシ、３は研磨スラリー液、５、６、７および８は支持ローラである。研磨剤の平均粒径は３０μｍであった。ナイロンブラシの材質は６・１０ナイロン、毛長は５０ｍｍ、毛の直径は０．４８ｍｍであった。ナイロンブラシはφ３００ｍｍのステンレス製の筒に穴をあけて密になるように植毛した（ブラシの毛密度は４５０本／ｃｍ^２であった。）。回転ブラシは３本使用した。ブラシ下部の２本の支持ローラ（φ２００ｍｍ）の距離は３００ｍｍであった。ブラシローラはブラシを回転させる駆動モータの負荷が、ブラシローラをアルミニウム板に押さえつける前の負荷に対して７ｋＷプラスになるまで押さえつけた。ブラシの回転方向はアルミニウム板の移動方向と同じであった。ブラシの回転数は２００ｒｐｍであった。
【０１３５】
（ｂ）アルカリエッチング処理
上記で得られたアルミニウム板をカセイソーダ濃度２．６質量％、アルミニウムイオン濃度６．５質量％、温度７０℃の水溶液を用いてスプレーによるエッチング処理を行い、アルミニウム板を６ｇ／ｍ^２溶解した。その後、スプレーによる水洗を行った。
【０１３６】
（ｃ）デスマット処理
温度３０℃の硝酸濃度１質量％水溶液（アルミニウムイオンを０．５質量％含む。）で、スプレーによるデスマット処理を行い、その後、スプレーで水洗した。デスマット処理に用いた硝酸水溶液は、硝酸水溶液中で交流を用いて電気化学的粗面化処理を行う工程の廃液を用いた。
【０１３７】
（ｄ）電気化学的粗面化処理
６０Ｈｚの交流電圧を用いて連続的に電気化学的な粗面化処理を行った。このときの電解液は、硝酸１０．５ｇ／Ｌ水溶液（アルミニウムイオンを５ｇ／Ｌ、アンモニウムイオンを０．００７質量％含む。）、液温５０℃であった。交流電源波形は図２に示した波形であり、電流値がゼロからピークに達するまでの時間ＴＰが０．８ｍｓｅｃ、ｄｕｔｙ比１：１、台形の矩形波交流を用いて、カーボン電極を対極として電気化学的な粗面化処理を行った。補助アノードにはフェライトを用いた。電解槽は図３に示すものを使用した。
電流密度は電流のピーク値で３０Ａ／ｄｍ^２、電気量はアルミニウム板が陽極時の電気量の総和で２２０Ｃ／ｄｍ^２であった。補助陽極には電源から流れる電流の５％を分流させた。
その後、スプレーによる水洗を行った。
【０１３８】
（ｅ）アルカリエッチング処理
アルミニウム板をカセイソーダ濃度２６質量％、アルミニウムイオン濃度６．５質量％の水溶液を用いてスプレーによるエッチング処理を３２℃で行い、アルミニウム板を０．２５ｇ／ｍ^２溶解し、前段の交流を用いて電気化学的粗面化処理を行ったときに生成した水酸化アルミニウムを主体とするスマット成分を除去し、また、生成したピットのエッジ部分を溶解してエッジ部分を滑らかにした。その後、スプレーによる水洗を行った。
【０１３９】
（ｆ）デスマット処理
温度３０℃の硫酸濃度１５質量％水溶液（アルミニウムイオンを４．５質量％含む。）で、スプレーによるデスマット処理を行い、その後、スプレーで水洗した。デスマット処理に用いた硝酸水溶液は、硝酸水溶液中で交流を用いて電気化学的粗面化処理を行う工程の廃液を用いた。
【０１４０】
（ｇ）電気化学的粗面化処理
６０Ｈｚの交流電圧を用いて連続的に電気化学的な粗面化処理を行った。このときの電解液は、塩酸７．５ｇ／Ｌ水溶液（アルミニウムイオンを５ｇ／Ｌ含む。）、温度３５℃であった。交流電源波形は図２に示した波形であり、電流値がゼロからピークに達するまでの時間ＴＰが０．８ｍｓｅｃ、ｄｕｔｙ比１：１、台形の矩形波交流を用いて、カーボン電極を対極として電気化学的粗面化処理を行った。補助アノードにはフェライトを用いた。電解槽は図３に示すものを使用した。
電流密度は電流のピーク値で２５Ａ／ｄｍ^２、電気量はアルミニウム板が陽極時の電気量の総和で５０Ｃ／ｄｍ^２であった。
その後、スプレーによる水洗を行った。
【０１４１】
（ｈ）アルカリエッチング処理
アルミニウム板をカセイソーダ濃度２６質量％、アルミニウムイオン濃度６．５質量％の水溶液を用いてスプレーによるエッチング処理を３２℃で行い、アルミニウム板を０．１０ｇ／ｍ^２溶解し、前段の交流を用いて電気化学的粗面化処理を行ったときに生成した水酸化アルミニウムを主体とするスマット成分を除去し、また、生成したピットのエッジ部分を溶解してエッジ部分を滑らかにした。その後、スプレーによる水洗を行った。
【０１４２】
（ｉ）デスマット処理
温度６０℃の硫酸濃度２５質量％水溶液（アルミニウムイオンを０．５質量％含む。）で、スプレーによるデスマット処理を行い、その後、スプレーによる水洗を行った。
【０１４３】
（ｊ）陽極酸化処理
図４に示す構造の陽極酸化装置を用いて陽極酸化処理を行った。第一および第二電解部に供給した電解液としては、硫酸を用いた。電解液は、いずれも、硫酸濃度１７０ｇ／Ｌ（アルミニウムイオンを０．５質量％含む。）、温度３８℃であった。その後、スプレーによる水洗を行った。最終的な酸化皮膜量は２．７ｇ／ｍ^２であった。
【０１４４】
＜表面処理Ｂ＞
上記表面処理Ａの（ｈ）アルカリエッチング処理において、アルミニウム板の溶解量を、１．０ｇ／ｍ^２とした以外は、表面処理Ａと同様の方法により、表面処理した。
【０１４５】
＜表面処理Ｃ＞
上記表面処理Ａの（ｇ）、（ｈ）、（ｉ）を行わなかった以外は、表面処理Ａと同様の方法により、表面処理した。
【０１４６】
＜表面処理Ｄ＞
上記表面処理Ａの（ａ）、（ｄ）、（ｅ）、（ｆ）を行わず、上記表面処理Ａの（ｇ）において、アルミニウム板が陽極時の電気量の総和を１２００Ｃ／ｄｍ^２とした以外は、表面処理Ａと同様の方法により、表面処理した。
【０１４７】
＜表面処理Ｅ＞
上記表面処理Ａの（ａ）、（ｇ）、（ｈ）、（ｉ）を行わなかった以外は、表面処理Ａと同様の方法により、表面処理した。
【０１４８】
２．平版印刷版用支持体の表面形状の測定
上記で得られた平版印刷版用支持体の表面の凹部について、下記（１）〜（４）の測定を行った。
結果を第２表に示す。なお、第２表中、「−」は、該当する平均波長または平均開口径の凹部がなかったことを示す。
【０１４９】
（１）中波構造の平均開口径
ＳＥＭを用いて支持体の表面を真上から倍率２０００倍で撮影し、得られたＳＥＭ写真においてピットの周囲が環状に連なっている中波構造のピット（中波ピット）を５０個抽出し、その直径を読み取って開口径とし、平均開口径を算出した。
【０１５０】
（２）小波構造の平均開口径
高分解能ＳＥＭを用いて支持体の表面を真上から倍率５００００倍で撮影し、得られたＳＥＭ写真において小波構造のピット（小波ピット）を５０個抽出し、その直径を読み取って開口径とし、平均開口径を算出した。
【０１５１】
（３）小波構造の開口径に対する深さの比の平均
小波構造の開口径に対する深さの比の平均は、高分解能ＳＥＭを用いて支持体の破断面を倍率５００００倍で撮影し、得られたＳＥＭ写真において開口径０．３μｍ以下の小波ピットを２０個抽出し、開口径と深さとを読み取って比を求めて平均値を算出した。
【０１５２】
（４）大波構造の平均波長
触針式粗さ計（ｓｕｆｃｏｍ５７５、東京精密社製）で２次元粗さ測定を行い、ＩＳＯ４２８７に規定されている平均山間隔Ｓ_ｍを５回測定し、その平均値を平均波長とした。２次元粗さ測定は、以下の条件で行った。
ｃｕｔ　ｏｆｆ０．８、傾斜補正ＦＬＡＴ−ＭＬ、測定長３ｍｍ、縦倍率１００００倍、走査速度０．３ｍｍ／ｓｅｃ、触針先端径２μｍ。
【０１５３】
【表２】

【０１５４】
【表３】

【０１５５】
３．平版印刷版原版の作成
上記で得られた各平版印刷版用支持体に、下記の画像記録層Ｉ〜ＩＩＩを設けて平版印刷版原版を得た。
なお、画像記録層Ｉ〜ＩＩＩを設ける前には、下記のアルカリ金属ケイ酸塩処理による親水化処理および下塗処理の界面処理を行った。
【０１５６】
上記で得られた平版印刷版用支持体を、温度３０℃の３号ケイ酸ソーダの１質量％水溶液の処理槽の中に１０秒間浸せきさせることで、アルカリ金属ケイ酸塩処理（シリケート処理）を行った。その後、井水を用いたスプレーによる水洗を行った。
上記のようにして得られたアルカリ金属ケイ酸塩処理後の平版印刷版用支持体上に、下記組成の下塗液を塗布し、８０℃で１５秒間乾燥し、塗膜を形成させた。乾燥後の塗膜の被覆量は１０ｍｇ／ｍ^２であった。
【０１５７】
＜下塗液組成＞
・下記高分子化合物　　０．２ｇ
・メタノール　　１００ｇ
・水　　１ｇ
【０１５８】
【化１】

【０１５９】
＜画像記録層Ｉ＞
下記組成の感熱層塗布液を調製し、下塗りした平版印刷版用支持体に、この感熱層塗布液を乾燥後の塗布量（感熱層塗布量）が１．７ｇ／ｍ^２になるよう塗布し、乾燥させて感熱層を形成させ、平版印刷版原版を得た。
【０１６０】
（感熱層塗布液組成）
・ノボラック樹脂（ｍ−クレゾール／ｐ−クレゾール＝６０／４０、重量平均分子量７，０００、未反応クレゾール０．５質量％含有）　　１．０ｇ
・下記構造式で表されるシアニン染料Ａ　　０．１ｇ
・テトラヒドロ無水フタル酸　　０．０５ｇ
・ｐ−トルエンスルホン酸　　０．００２ｇ
・エチルバイオレットの対イオンを６−ヒドロキシ−β−ナフタレンスルホン酸にしたもの　　０．０２ｇ
・フッ素系界面活性剤（メガファックＦ−１７７、大日本インキ化学工業社製）　０．０５ｇ
・メチルエチルケトン　　１２ｇ
【０１６１】
【化２】

【０１６２】
＜画像記録層ＩＩ＞
上記下塗りした平版印刷版用支持体上に、バーを用いて下記組成の感光液を塗布し、１２０℃で４０秒間乾燥して感光層を形成させた。乾燥後の感光層の重量は１．０ｇ／ｍ^２であった。
（感光液組成）

【０１６３】
【化３】

【０１６４】
このようにして設けた感光層の上に、下記組成のマット液を静電スプレーで吹きつけ塗布し、６０℃で５秒間乾燥して表面にマットを付着させ、平版印刷版原版を得た。
液滴の数は５０〜１００個／ｍｍ^２であり、乾燥後のマットの重量は０．０５ｇ／ｍ^２、高さは２〜６μｍ、直径は２０〜１５０μｍであった。
（マット液組成）
・２−アクリルアミド−２−メチルプロパン酸ナトリウム／エチルアクリレート／メチルメタクリレート＝１５／１５／７０（モル比）　の共重合体（重量平均分子量１０万）　　　　２０．０ｇ
・タートラジン（水溶性染料）　　　０．　１ｇ
・純水　　　７９．９ｇ
【０１６５】
＜画像記録層ＩＩＩ＞
上記下塗りした平版印刷版用支持体上に、まず、バーを用いて下記組成の中間層液を塗布し、８０℃で２０秒間乾燥することで、中間層を設けた。乾燥後の中間層の塗布重量は０．００５ｇ／ｍ^２であった。
（中間層液組成）
・２−アクリルアミド−２−メチルプロパン酸ナトリウム／エチルアクリレート／メチルアクリレート＝２０／３０／５０（モル比）の共重合体（重量平均分子量７万）　　　１．０ｇ
・メタノール　　　９０．０ｇ
・純粋　　　９．０ｇ
【０１６６】
次に、バーを用いて、下記組成の感光液を塗布し、１３０℃で４０秒間乾燥することで、感光層を設けた。乾燥後の中間層の重量は１．５ｇ／ｍ^２であった。
（感光液組成）
・４，４’−ジフェニルメタンジイソシアネート／ヘキサメチレンジイソシアネート／２，２−ビス（ヒドロキシメチル）プロピオン酸／テトラエチレングリコール＝４０／１０／３５／１５（モル比）のウレタン樹脂（重量平均分子量１０万）　　　２．５ｇ
・メタクリル酸／メチルメタクリレート／２−ヒドロキシエチルメタクリレート／アクリロニトリル＝５／３５／４０／２０（モル比）の共重合体（重量平均分子量８万）　　　２．５ｇ
・４−ジアゾジフェニルアミンとホルムアルデヒドとの縮合物のドデシルベンゼンスルホン酸塩（ジアゾ樹脂）　　　１．２ｇ
・スチレン／無水マレイン酸＝５０／５０（モル比）の共重合体（重量平均分子量３万）のｎ−ヘキシルアルコールによるハーフエステル　　　０．１ｇ
・ビクトリアピュアブルーＢＯＨ（保土ヶ谷化学社製）　　　０．　１５ｇ
・メガファックＦ−１７６ＰＦ（大日本インキ化学工業（株）製フッ素系界面活
性剤）　　　　　　　０．　１ｇ
・リン酸トリクレジル　　　０．１５ｇ
・亜リン酸　　０．０２ｇ
・りんご酸　　０．０２ｇ
・プロピレングリコールモノメチルエーテル　　４０ｇ
・メチルエチルケトン　　　　３０ｇ
・メタノール　　　　２０ｇ
・乳酸メチル　　１０ｇ
・純水　　　１．５ｇ
【０１６７】
このようにして設けた感光層の上に、下記組成のマット液を静電スプレーで吹きつけ塗布し、６０℃で５秒間乾燥して表面にマットを付着させ、平版印刷版原版を得た。
液滴の数は５０〜１５０個／ｍｍ^２であり、乾燥後のマットの重量は０．１０ｇ／ｍ^２、高さは２〜６μｍ、直径は２０〜１５０μｍであった。
（マット液組成）
・２−アクリルアミド−２−メチルプロパン酸ナトリウム／エチルアクリレート／メチルメタクリレート＝１５／１５／７０（モル比）　の共重合体（重量平均分子量１０万）　　　　　　２０．０ｇ
・タートラジン（水溶性染料）　　　０．　１ｇ
・純水　　　７９．９ｇ
【０１６８】
４．露光および現像処理
上記で得られた、画像記録層Ｉ〜ＩＩＩを設けた各平版印刷版原版に、該画像記録層に応じて下記の方法で画像露光および現像処理を行い、平版印刷版を得た。
【０１６９】
＜画像記録層Ｉを設けた平版印刷版原版＞
画像記録層Ｉを設けた平版印刷版原版を出力５００ｍＷ、波長８３０ｎｍビーム径１７μｍ（１／ｅ^２）の半導体レーザーを装備したＣＲＥＯ社製ＴｒｅｎｎｄＳｅｔｔｅｒ３２４４を用いて主走査速度５ｍ／秒、版面エネルギー量１４０ｍＪ／ｃｍ^２で像様露光した。なお、後述するポツ状残膜の発生の有無を評価するのために、版面エネルギー量を２０〜１４０ｍＪ／ｃｍ^２まで２０ｍＪ／ｃｍ^２おきに変えて露光を行ったサンプルを準備した。
その後、非還元糖と塩基とを組み合わせたＤ−ソルビット／酸化カリウムＫ_２Ｏよりなるカリウム塩５．０質量％およびオルフィンＡＫ−０２（日信化学社製）０．０１５質量％を含有する水溶液１Ｌに下記化合物ａを添加したアルカリ現像液を用いて現像処理を行った。現像処理は、上記アルカリ現像液を満たした自動現像機ＰＳ９００ＮＰ（富士写真フイルム（株）製）を用いて、現像温度２５℃、１２秒の条件で行った。現像処理が終了した後、水洗工程を経て、ガム（ＧＵ−７（１：１））等で処理して、製版が完了した平版印刷版を得た。なお、化合物ａの代わりに、下記化合物ｂまたはｃを同じ添加量で添加したアルカリ現像液を用いた場合であっても、同様に現像処理を行うことができた。
＜化合物ａ〜ｃ＞
化合物ａ：Ｃ_１２Ｈ_２５Ｎ（ＣＨ_２ＣＨ_２ＣＯＯＮａ）_２
化合物ｂ：Ｃ_１２Ｈ_２５Ｏ（ＣＨ_２ＣＨ_２Ｏ）_７Ｈ
化合物ｃ：（Ｃ_６Ｈ_１３）_２ＣＨＯ（ＣＨ_２ＣＨ_２Ｏ）_２０Ｈ
【０１７０】
＜画像記録層ＩＩを設けた平版印刷版原版＞
上記画像記録層ＩＩを設けた平版印刷版原版の上に網点ネガフィルムを重ね、米国ヌアーク社製プリンタＦＴ２６Ｖ２ＵＰＮＳ（光源；２ＫＷメタルハライドランプ）で２００カウント露光した。なお、後述するポツ状残膜の発生の有無を評価するのために、カウント数を１００〜２００カウントまで１０カウントおきに変えて露光を行ったサンプルを準備した。
その後、富士写真フイルム（株）製自動現像機９００ＮＰを用いて現像処理およびガム液の塗布を行った。その際現像液としては下記組成の現像液を、ガム液としては下記組成のガム液を用いた。現像液の温度は３０℃にし、現像液への浸透時間が１２秒になるように搬送速度を調整した。
【０１７１】
（現像液組成）
・［ＳｉＯ_２］／［Ｋ_２Ｏ］のモル比が１．　２で、ＳｉＯ_２濃度が２．　１質量％のケイ酸カリウム水溶液　　　９９９ｇ
・エチレンジアミン四酢酸の二ナトリウム塩　　　　　１ｇ
（ガム液組成）
・アラビアガム　　　　５．　０ｇ
・白色デキストリン　　　３０ｇ
・エチレングリコール　　　１０ｇ
・リン酸　　　　　３ｇ
・水　　　９５２ｇ
【０１７２】
＜画像記録層ＩＩＩを設けた平版印刷版原版＞
上記画像記録層ＩＩを設けた平版印刷版原版の上に網点ネガフィルムを重ね、米国ヌアーク社製プリンタＦＴ２６Ｖ２ＵＰＮＳ（光源；２ＫＷメタルハライドランプ）で２００カウント露光した。なお、後述するポツ状残膜の発生の有無を評価するのために、カウント数を１００〜２００カウントまで１０カウントおきに変えて露光を行ったサンプルを準備した。
その後、富士写真フイルム（株）製自動現像機９００Ｎを用いて現像処理およびガム液の塗布を行った。その際現像液現像補充液としてはＤＮ−６（富士写真フイルム（株）製現像液）、ガム液としては、ＦＮ−２（富士写真フイルム（株）製ガム液）をそれぞれ用いた。
第１現像液の温度は３０℃にし、第１現像液への浸透時間が１２秒になるように搬送速度を調整した。
【０１７３】
５．平版印刷版の評価
上記で得られた平版印刷版のポツ状残膜の発生の有無、耐汚れ性および耐刷性を下記の方法で評価した。それぞれの結果を第３表に示す。
なお、下記評価方法は、各平版印刷版用支持体に上記３種類の画像記録層Ｉ〜ＩＩＩを設けた各平版印刷版原版を露光現像した平版印刷版３種類で行った。各実施例および比較例における評価は、それら３種類の平版印刷版の平均値を示した。
【０１７４】
（１）ポツ状残膜の発生の有無
各版面エネルギー量または各カウント数で露光したサンプルの現像後の非画像部を光学顕微鏡で倍率１００倍で観察し、１ｍｍ四方の面積におけるポツの有無を調べた。ポツが観察されないサンプルの版面エネルギー量またはカウント数の最小値により、ポツ状残膜の発生の有無を評価した。版面エネルギー量またはカウント数が小さい方から順に、数値で１０〜１の１０段階で表した。
該数値が大きい方ほどポツ状残膜が発生しにくいことを意味している。
【０１７５】
（２）耐汚れ性
耐汚れ性については、ブランケット汚れについて評価した。
三菱ダイヤ型Ｆ２印刷機（三菱重工業社製）で、ＤＩＣ−ＧＥＯＳ（ｓ）紅のインキを用いて印刷し、１万枚印刷した後におけるブランケットの汚れを目視で評価した。
ブランケットの汚れが少ない方から順に、数値で１０〜１の１０段階で表した。数字が大きいほど耐汚れ性に優れることを意味している。
【０１７６】
（３）耐刷性
小森コーポレーション社製のリスロン印刷機で、大日本インキ化学工業社製のＤＩＣ−ＧＥＯＳ（Ｎ）墨のインキを用いて印刷し、ベタ画像の濃度が薄くなり始めたと目視で認められた時点の印刷枚数により、耐刷性を評価した。
耐刷性は、比較例１の平版印刷版用支持体に上記３種類の画像記録層を設けた平版印刷版の印刷枚数の平均枚数を１００としたときの、各実施例および比較例の平均印刷枚数を相対値で表した。
【０１７７】
【表４】

【０１７８】
【表５】

【０１７９】
第２表および第３表から明らかなように、低純度アルミニウム板を用い、特定の凹凸構造を持つ平版印刷版用支持体上に画像記録層を設けた平版印刷版原版は、ポツ状残膜の発生がなく耐汚れ性に優れ、また耐刷性にも優れる（実施例１〜５）。
特に、引張り強度が１６０ＭＰａ以上の低純度アルミニウム板を用いた平版印刷版用支持体上に画像記録層を設けた平版印刷版原版は、ポツ状残膜の発生をより効果的に抑えることができ、耐汚れ性および耐刷性にも優れる（実施例１〜４）。
また、小波構造の開口径に対する深さの比の平均が０．２以上であると、耐刷性が特に向上する。
【０１８０】
【発明の効果】
以上に説明したように、低純度アルミニウム板、好ましくはその引張り強度が特定範囲の低純度アルミニウム板に表面処理等して得られる、特定波長の大波構造および特定開口径の中波、小波構造とを重畳した構造の砂目形状を表面に有する本発明の平版印刷版用支持体を用いれば、ポツ状残膜の発生を効果的に抑えることができ、また従来トレードオフの関係から脱しえなかった耐汚れ性と耐刷性との両立もできる。
【図面の簡単な説明】
【図１】本発明の平版印刷版用支持体の作成における機械粗面化処理に用いられるブラシグレイニングの工程の概念を示す側面図である。
【図２】本発明の平版印刷版用支持体の作成における電気化学的粗面化処理に用いられる交番波形電流波形図の一例を示すグラフである。
【図３】本発明の平版印刷版用支持体の作成における交流を用いた電気化学的粗面化処理におけるラジアル型セルの一例を示す側面図である。
【図４】本発明の平版印刷版用支持体の作成における陽極酸化処理に用いられる陽極酸化処理装置の概略図である。
【符号の説明】
１　アルミニウム板
２、４　ローラ状ブラシ
３　研磨スラリー液
５、６、７、８　支持ローラ
１１　アルミニウム板
１２　ラジアルドラムローラ
１３ａ、１３ｂ　主極
１４　電解処理液
１５　電解液供給口
１６　スリット
１７　電解液通路
１８　補助陽極
１９ａ、１９ｂ　サイリスタ
２０　交流電源
４０　主電解槽
５０　補助陽極槽
４１０　陽極酸化処理装置
４１２　給電槽
４１４　電解処理槽
４１６　アルミニウム板
４１８、４２６　電解液
４２０　給電電極
４２２、４２８　ローラ
４２４　ニップローラ
４３０　電解電極
４３２　槽壁
４３４　直流電源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lithographic printing plate support and a lithographic printing plate precursor using the lithographic printing plate, and in particular, when used as a lithographic printing plate, there is no generation of a pot-like residual film and excellent stain resistance and printing durability. The present invention relates to an excellent lithographic printing plate support using a low-purity aluminum plate, and further to a lithographic printing plate precursor using the same.
[0002]
[Prior art]
The lithographic printing method is a printing method that utilizes the fact that water and oil are not essentially mixed. The printing plate surface of the lithographic printing plate used for this is a region that accepts water and repels oil-based ink (hereinafter referred to as “removal”). This region is referred to as a “non-image portion”) and a region that repels water and receives oil-based ink (hereinafter, this region is referred to as “image portion”).
[0003]
An aluminum support for a lithographic printing plate used for a lithographic printing plate (hereinafter simply referred to as a “support for a lithographic printing plate”) is used so that its surface bears a non-image portion, and therefore has hydrophilicity and water retention. Are required to have various performances which are contradictory to each other, for example, excellent adhesion, and excellent adhesion to an image recording layer provided thereon.
If the hydrophilicity of the support is too low, ink will adhere to the non-image area during printing, and the blanket cylinder will be soiled, and so-called background soiling will occur. On the other hand, if the water holding capacity of the support is too low, the shadow portion is clogged unless dampening water is increased during printing. Therefore, the so-called water width is narrowed.
[0004]
On the other hand, if a deep concave portion exists on the surface of the support subjected to the roughening treatment, the thickness of the image recording layer at that portion becomes thick, so that development may be suppressed in shape. As a result of the development being suppressed, the image recording layer remains in the deep concave portion, and a local residual film (hereinafter also referred to as “spot-like residual film”) is generated in the non-image area. There is a problem that the non-image area is stained. For example, in a lithographic printing plate precursor provided with a so-called thermal type image recording layer in which the solubility in an alkali developer changes due to heat generated by photothermal conversion, the image formation reaction is insufficient at the bottom of the concave portion, and a pot-like residual film Will occur.
Such a pot-like residual film is likely to occur when the conditions of exposure and development are severe. For example, in a planographic printing plate precursor provided with a thermal type image recording layer, the exposure time is shortened to improve productivity, or the laser beam energy is lowered to extend the life of the laser. This is a case where the exposure amount is reduced. In addition, in order to use an image recording layer that tends to cause image omission in a portion that should originally be an image portion with a highly active developer with high sensitivity, there is a case where development is performed using a developer with low sensitivity. is there.
[0005]
In order to obtain a lithographic printing plate support having good performance, it is common to make the surface of an aluminum plate grained (roughening treatment) to give irregularities. As for the unevenness, various shapes (structures) have been proposed as shown below.
For example, a triple structure (see Patent Document 1) having a large wave, a medium wave and a small wave defining the opening diameters of the medium wave and the small wave (see Patent Document 1), and a structure defining the diameter of the small wave in a large and small double structure (for example, Patent Document 2) , See Patent Document 3), a technique for providing fine protrusions in addition to large and small double recesses (pits) (see Patent Document 4), and a double structure that defines an opening diameter (see Patent Document 5). ), A double structure (see Patent Document 6) defining a factor a30 indicating the smoothness of the surface, and a plurality of electrochemical roughening treatments (hereinafter also referred to as “electrolytic roughening treatment”). A structure (see Patent Document 7) that defines the ratio of pit diameters to be formed has been proposed.
[0006]
This graining includes mechanical graining methods such as ball graining, brush graining, wire graining, and blast graining, and an electrolytic grained surface for electrolytic etching of an aluminum plate in an electrolyte containing hydrochloric acid and / or nitric acid. And a composite roughening method (see Patent Document 8) in which a mechanical roughening method and an electrolytic roughening method are combined.
[0007]
[Patent Document 1]
JP-A-8-300844
[Patent Document 2]
JP 11-99758 A
[Patent Document 3]
Japanese Patent Laid-Open No. 11-208138
[Patent Document 4]
JP 11-167207 A
[Patent Document 5]
Japanese Patent No. 2023476
[Patent Document 6]
JP-A-8-300843
[Patent Document 7]
Japanese Patent Laid-Open No. 10-35133
[Patent Document 8]
US Pat. No. 4,476,006
[0008]
[Problems to be solved by the invention]
However, in the above-mentioned prior art, deep recesses are easily formed, and the occurrence of a pot-like residual film cannot be effectively suppressed, and the stain resistance and the printing durability are in a trade-off relationship. And printing durability were not compatible.
Therefore, the present invention solves this problem and provides a support for a lithographic printing plate that is free from the occurrence of a pot-like residual film and has excellent stain resistance and printing durability when used as a lithographic printing plate. For the purpose.
Another object of the present invention is to provide a lithographic printing plate precursor using the above support.
[0009]
[Means for Solving the Problems]
As a result of intensive studies on the aluminum plate used for the support for lithographic printing plates and the uneven structure of the surface, the inventor has obtained a uniform large wave structure by mechanical roughening by using a low-purity aluminum plate. Since it is formed and the formation of deep recesses is suppressed, and because the adhesion between the recording layer and the support is excellent by combining irregularities of a specific size on the surface of the low-purity aluminum or the like, lithographic printing As a plate, it was found that there was no occurrence of a pot-like residual film, excellent stain resistance, and excellent printing durability, and the present invention was completed.
[0010]
That is, this invention is made | formed based on the said knowledge, and provides the following (1)-(4).
[0011]
(1) A lithographic printing plate support obtained by subjecting an aluminum plate to a roughening treatment including a mechanical roughening treatment and an anodizing treatment,
The aluminum content of the aluminum plate is 95% by mass or more and less than 99.50% by mass,
Lithographic printing having a grained shape on the surface with a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.20 μm superimposed on each other Plate support.
[0012]
(2) The lithographic printing plate support according to (1), wherein the aluminum plate has a tensile strength of 160 MPa or more.
[0013]
(3) The lithographic printing plate support according to (1) or (2), wherein the average ratio of the depth to the opening diameter of the small wave structure is 0.2 or more.
[0014]
(4) A lithographic printing plate precursor in which an image recording layer is provided on the lithographic printing plate support according to any one of (1) to (3).
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
The aluminum alloy plate (hereinafter simply referred to as “aluminum plate”) used in the present invention is a metal whose main component is dimensionally stable aluminum, and the aluminum content is 95% by mass or more and less than 99.50% by mass. Preferably, the tensile strength is 160 MPa or more.
In the present invention, low purity aluminum refers to aluminum having an aluminum content of 95% by mass or more and less than 99.50% by mass.
[0016]
<Aluminum plate (rolled aluminum)>
The aluminum plate used in the present invention has an aluminum content of 95% by mass or more. An aluminum plate of less than 50% by mass. That is, it contains 0.50 to 5% by mass of elements other than aluminum. The trace elements contained in these aluminum alloys preferably contain the following elements in the following amounts. Here, the amount of inevitable impurities other than the following elements is preferably 0.06% by mass or less.
If the purity is 99.50% by mass (hereinafter sometimes referred to as “wt%”) or more, the allowable amount of impurities decreases, and the cost reduction effect may decrease. If the content is lower than 95 wt%, defects such as cracks may occur during rolling due to containing a large amount of impurities. More preferably, the purity of aluminum is 95 to 99 wt%, more preferably 95 to 97 wt%.
[0017]
The aluminum content is 95% by mass or more. As an aluminum alloy of less than 50% by mass, it is not an aluminum lump with a purity of 99.7% or more called a new bullion, such as scrap aluminum, secondary bullion, recycled bullion, etc. An aluminum lump having such a low purity can be mentioned. By using a low-purity aluminum lump as a raw material, a lithographic printing plate support can be produced at a lower cost than the conventional method, and the tensile strength of the aluminum plate can be increased, resulting in deep mechanical roughening treatment. The formation of the recess can be effectively suppressed.
[0018]
The elements contained in the aluminum plate of the present invention will be described.
Fe is an element contained in the new metal in the range of about 0.1 to 0.2 wt%, and the amount dissolved in aluminum is small, and most remains as an intermetallic compound. Although there exists an effect | action which raises mechanical strength, when more than 1.0 wt%, it will become easy to generate | occur | produce a crack in the middle of rolling, and 0.1 wt% or less is not realistic. As an intermetallic compound, Al₃Fe, Al₆Typical examples include Fe, AlFeSi-based compounds, and AlFeSiMn-based compounds.
[0019]
Si is an element contained in a new metal in the range of about 0.03 to 0.1 wt%, and is also contained in a large amount in scrap Al. It exists as a solid solution in aluminum, as an intermetallic compound, or as a single precipitate. In addition, when heated in the process of producing a lithographic printing plate support, the dissolved Si may precipitate as elemental Si. It is known that when the amount of simple Si is excessive, severe ink stains are reduced. Also, it affects the electrochemical roughening property. Examples of intermetallic compounds include AlFeSi compounds, AlFeSiMn compounds, Mg₂Si and the like are typical.
[0020]
Cu is contained in trace amounts in the new metal. Moreover, it is an element contained abundantly in scrap of JIS2000 series and 4000 series materials. It is relatively easy to dissolve in aluminum. Cu is an element that greatly affects the electrochemical roughening performance.
[0021]
Mg is contained in trace amounts in new bullion. Moreover, it is an element contained in many scraps of JIS2000, 3000, 5000, and 7000 materials. In particular, it is one of the main impurity metals contained in scrap material because it is contained in a large amount in can end material. Heat resistance softening property and mechanical strength can be improved by adding Mg. It is also known that it is relatively easily dissolved in aluminum and forms an intermetallic compound with Si.
[0022]
Mn is contained in trace amounts in new bullion. Mn is an element contained in a large amount in scrap of JIS 3000 series materials. In particular, it is one of the main impurity metals contained in scrap materials because it is contained in a large amount in can body materials. Mn is also relatively easily dissolved in aluminum, and forms an intermetallic compound with Al, Fe, Si and the like. Mn improves the mechanical strength and affects the electrochemical roughening property.
[0023]
Zn is contained in trace amounts in the new bullion. Zn is an element that is particularly abundant in JIS7000 series scrap. It is relatively easy to dissolve in aluminum. Affects electrochemical roughening.
[0024]
Cr may be contained in a very small amount in new bullion. Moreover, it may be contained in a small amount in JIS 5000 series, 6000 series, and 7000 series scraps.
[0025]
Ti is an element usually added in an amount of 0.01 to 0.04 wt% as a crystal refining material. Mainly intermetallic compound with Al or TiB₂Added in the form of JIS 5000 series, 6000 series, and 7000 series scraps contain relatively large amounts of impurity metals. If it is contained in excess, it may affect the electrochemical surface roughness.
[0026]
B may be added together with Ti as a crystal refining material, and may be included as long as it is 0.04 wt% or less.
[0027]
Elements contained in aluminum raw materials or elements added to molten aluminum melt into the aluminum (solid solution) when solidified in the casting process, and the rest are intermetallic compounds or single crystallized products -Present as a precipitate. The proportion remaining as an intermetallic compound or as a single crystallized product / precipitate is greatly affected by the solidification rate. For example, when solidifying rapidly as in the case of a phase roll type continuous casting, most of the solid solution is formed, and DC casting. When the solidification rate is slow as in the above, it is relatively easy to remain as an intermetallic compound or a single crystallized product / precipitate.
Then, during heat treatment processes such as soaking, annealing, etc., and during hot rolling, it is re-dissolved in Al or changed to a more stable intermetallic compound, but the thickness is about 0.1 to 0.7 mm When an aluminum plate for a lithographic printing plate is obtained, it is often present as an intermetallic compound or as a single crystallized product / precipitate on the surface and inside thereof.
[0028]
The aluminum plate used in the present invention preferably has a tensile strength of 160 MPa or more. If the tensile strength of the aluminum plate is 160 MPa or more, the formation of deep pits can be suppressed even when the processing conditions are not strictly defined in the mechanical surface roughening treatment described later, and the surface is not suitable for a lithographic printing plate. The generation of residual film can be suppressed and the stain resistance is excellent. The tensile strength of the aluminum plate is more preferably 200 MPa or more, and particularly preferably 220 MPa or more.
The tensile strength of the aluminum plate is preferably 260 MPa or less, and more preferably 240 MPa or less. If the tensile strength of the aluminum plate exceeds 260 MPa, the large wave structure formed by the mechanical surface roughening treatment becomes too shallow or not formed, so that the hydrophilicity and water retention of the support surface are poor, and water The width may be narrowed. In addition, when attached to a printing press, the fit to the plate cylinder is poor, which may lead to color misregistration of the printed matter and plate breakage during printing.
[0029]
In order to obtain an aluminum plate having a tensile strength of 160 MPa or more, it can be usually cast according to the following method using a molten aluminum alloy having the above aluminum content. In particular, the strength of the obtained aluminum plate can be adjusted by adjusting the rolling reduction in the final rolling step. It can also be achieved by carrying out a process called intermediate annealing at an early stage where the thickness of the aluminum plate is thick.
Alternatively, it is known that iron, magnesium, and the like contained in aluminum affect the strength of the aluminum alloy, and the content of these elements may be adjusted.
[0030]
In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter that uses alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or a combination of a degassing process and a filtering process is performed.
[0031]
These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.
[0032]
Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. Regarding the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. When the temperature is less than 1 ° C., many coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be manufactured. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient.
[0033]
Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.
[0034]
The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve the productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.
[0035]
On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a double belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.
[0036]
When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.
[0037]
These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. Regarding the intermediate annealing condition and the cold rolling condition when using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, It is described in JP-A-8-92709.
[0038]
Various characteristics described below are desired for the aluminum plate thus manufactured.
In order to obtain a certain level of waist strength even when performing a burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and is 100 MPa or more. Is more preferable. In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used, but if the waist is strengthened, the ease of fitting to the plate cylinder of a printing press becomes inferior. Depending on the application, the material and the amount of trace components added are appropriately selected. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 7-126820 and 62-140894.
[0039]
The crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.
[0040]
The alloy component distribution of the aluminum plate, when chemical surface roughening treatment or electrochemical surface roughening treatment is performed, poor surface quality occurs due to non-uniform distribution of the alloy component on the surface of the aluminum plate. Therefore, it is preferable that the surface is not very uneven. With regard to these, the techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-48058, 5-301478, and 7-132689.
[0041]
In the intermetallic compound of the aluminum plate, the size and density of the intermetallic compound may affect the chemical roughening treatment or the electrochemical roughening treatment. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 7-138687 and 4-254545.
[0042]
In the present invention, an aluminum plate as shown above can be used with unevenness by lamination rolling, transfer or the like in the final rolling step.
[0043]
The aluminum plate used in the present invention is a continuous belt-like sheet material or plate material. That is, it may be an aluminum web or a sheet-like sheet cut to a size corresponding to a planographic printing plate precursor shipped as a product.
Since scratches on the surface of the aluminum plate may become defects when processed into a lithographic printing plate support, it is possible to generate scratches at the stage prior to the surface treatment process for making a lithographic printing plate support It is necessary to suppress as much as possible. For that purpose, it is preferable that the package has a stable form and is not easily damaged during transportation.
In the case of an aluminum web, for example, the packing form of aluminum is, for example, laying a hardboard and felt on an iron pallet, applying cardboard donut plates to both ends of the product, wrapping the whole with a polytube, and inserting a wooden donut into the inner diameter of the coil Then, a felt is applied to the outer periphery of the coil, the band is squeezed with a band, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and a needle felt or a hard board can be used as the cushioning material. There are various other forms, but the present invention is not limited to this method as long as it is stable and can be transported without being damaged.
[0044]
The thickness of the aluminum plate used in the present invention is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and more preferably 0.2 to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, the user's desires, and the like.
[0045]
In this manner, an aluminum plate having an aluminum content of 95% by mass or more and less than 99.50% by mass and preferably a tensile strength of 160 MPa or more can be obtained.
[0046]
On the other hand, an aluminum plate (tempered aluminum) having a tensile strength of less than 160 MPa can be obtained even when the molten aluminum alloy having a high impurity content is used. For example, an aluminum plate having a tensile strength of 160 MPa or less can be obtained by annealing after finishing to a desired thickness.
An aluminum plate having a tensile strength of less than 160 MPa obtained by the above-described method or the like is prone to forming deep pits in the mechanical surface roughening treatment. It is not preferable.
[0047]
The tensile strength of the aluminum plate is measured according to JIS Z2201 and JIS Z2241.
[0048]
The aluminum plate thus obtained contains an intermetallic compound composed of three or more kinds of metal elements as described above, and the density of the intermetallic compound existing within 2 μm from the surface layer is 3000 to 35000 pieces / mm.²Is preferred.
[0049]
The present inventors have found that these intermetallic compounds (particles) serve as pitting base points for pits formed by the electrochemical surface roughening treatment, and the intermetallic compounds are uniformly present within 2 μm from the surface layer. I found that it was possible to make a fine grain. When the density of the intermetallic compound is within the above range, dense pits are uniformly formed and the stain resistance is excellent.
[0050]
The density (abundance) of the intermetallic compound can be controlled by changing the amount of the raw material containing impurities or the amount of secondary metal added. It can also be adjusted slightly by appropriately changing the production conditions (surface treatment conditions) of the lithographic printing plate support. For example, the density can be lowered by removing the intermetallic compound by chemical etching using hydrochloric acid.
[0051]
The density of the intermetallic compound is 60 μm × 50 μm at 5 locations (n = 5), for example, by observing the surface of the roughened lithographic printing plate support with an SEM (scanning electron microscope) or the like. In range, count intermetallic compounds, 1mm²It can be easily calculated by converting to a per unit.
In addition, the density of the intermetallic compound is measured by using an EPMA (Electron Probe Microanalyzer), for example, in a range of 170 μm × 170 μm to count the intermetallic compound,²It can also be easily calculated by converting to a hit. When using EPMA, the kind of intermetallic compound can also be specified.
[0052]
<Surface grain shape>
The lithographic printing plate support of the present invention has a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.20 μm. It has a grain shape of structure on its surface.
In the present invention, the large wave structure having an average wavelength of 5 to 100 μm is involved in the generation of a pot-like residual film and the printing performance. If a deep concave portion is formed as a large wave structure, the image recording layer remains in the deep concave portion when exposure is insufficient or when it cannot be completely removed by development processing, resulting in a pop-like residual film. In some cases, the non-image area may become dirty during printing. On the other hand, when a shallow concave portion is formed as a large wave structure, hydrophilicity and water retention are deteriorated, and printing performance such as stain resistance may be inferior.
[0053]
This large wave structure has the effect of increasing the amount of water retained on the surface of the non-image part of the lithographic printing plate. The more water is retained on the surface, the less the surface of the non-image area is affected by contamination in the atmosphere, and a non-image area that is less likely to get dirty even when the plate is left in the middle of printing can be obtained. Further, when the large wave structure is formed, it becomes easy to visually confirm the amount of dampening water given to the printing plate during printing. That is, the plate inspection property of the planographic printing plate is excellent. If the average wavelength of the large wave structure is less than 5 μm, there may be no difference from the medium wave structure. If the average wavelength of the large wave structure exceeds 100 μm, the exposed non-image area may appear glaring after exposure and development, which may impair plate inspection. The average wavelength of the large wave structure is preferably 10 to 80 μm.
[0054]
The medium wave structure having an average opening diameter of 0.5 to 5 μm has a function of holding the image recording layer mainly by an anchor (throwing) effect and imparting printing durability. When the average opening diameter of the pits having a medium wave structure is less than 0.5 μm, the adhesiveness with the image recording layer provided on the upper layer is lowered, and the printing durability of the lithographic printing plate may be lowered. Further, when the average opening diameter of the pits having the medium wave structure exceeds 5 μm, the number of pit boundary portions serving as anchors is reduced, so that the printing durability may also be lowered.
[0055]
The small wave structure with an average opening diameter of 0.01 to 0.20 μm superimposed on the medium wave structure mainly serves to improve the stain resistance. By combining the medium wave structure with the small wave structure, when dampening water is supplied to the lithographic printing plate during printing, a water film is uniformly formed on the surface of the lithographic printing plate, thereby suppressing the occurrence of stains on the non-image area. it can. When the average opening diameter of the pits having the small wave structure is less than 0.01 μm, a large effect may not be obtained in forming a water film. On the other hand, when the average opening diameter of the pits having the small wave structure exceeds 0.20 μm, the medium wave structure is destroyed, and the effect of improving the printing durability by the medium wave structure may not be obtained.
[0056]
With this small wave structure, not only the opening diameter of the pit but also the depth of the pit can be controlled to obtain even better stain resistance. That is, it is preferable that the average of the ratio of the depth to the opening diameter of the small wave structure is 0.2 or more. As a result, the uniformly formed water film is reliably held on the surface, and the stain resistance of the surface of the non-image part is maintained for a long time.
[0057]
In the lithographic printing plate support of the present invention, the average opening diameter of the medium wave structure on the surface, the average opening diameter of the small wave structure, the average of the depth relative to the opening diameter, and the measurement method of the average wavelength of the large wave are as follows. It is.
[0058]
(1) Average opening diameter of medium wave structure
The surface of the support was photographed at a magnification of 2000 times from directly above using an electron microscope, and in the obtained electron micrograph, at least 50 pits (medium wave pits) having a medium wave structure in which the periphery of the pits are connected in a ring shape. Extract, read the diameter and use it as the opening diameter, and calculate the average opening diameter. The same method is used for a structure with a large wave structure superimposed. In addition, in order to suppress variation in measurement, it is possible to perform equivalent circle diameter measurement using commercially available image analysis software. In this case, the electron micrograph is captured by a scanner, digitized, and binarized by software, and then an equivalent circle diameter is obtained.
As a result of measurement by the present inventor, the result of visual measurement and the result of digital processing showed almost the same value. The same applies to the structure in which the large wave structure is superimposed.
[0059]
(2) Average aperture diameter of small wave structure
Using a high-resolution scanning electron microscope (SEM), the surface of the support was photographed from directly above at a magnification of 50000 times, and at least 50 small-wave structure pits (small-wave pits) were extracted from the obtained SEM photograph. Is read as the opening diameter, and the average opening diameter is calculated.
[0060]
(3) Average ratio of depth to aperture diameter of small wave structure
The average ratio of the depth to the aperture diameter of the wavelet structure is obtained by photographing the fracture surface of the support at a magnification of 50000 times using a high-resolution SEM, extracting at least 20 wavelet pits from the obtained SEM photograph, And the depth are read to find the ratio and the average value is calculated.
[0061]
(4) Average wavelength of large wave structure
Two-dimensional roughness measurement is performed with a stylus type roughness meter, and the average peak interval S defined in ISO 4287 is measured._mIs measured five times, and the average value is taken as the average wavelength.
[0062]
<Surface treatment>
The lithographic printing plate support of the present invention is one in which the above-described surface grain shape is formed on the surface of the aluminum plate by subjecting the above-described aluminum plate to surface treatment. The lithographic printing plate support of the present invention is obtained by subjecting an aluminum plate to roughening treatment including mechanical roughening and electrochemical roughening treatment and anodizing treatment. Is not particularly limited, and may include various steps other than the roughening treatment including mechanical roughening and electrochemical roughening treatment and anodizing treatment.
In the following, as a representative method for forming the above-described surface grain shape,
A method of sequentially performing mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with an acid and electrochemical surface roughening treatment using an electrolytic solution on an aluminum plate,
A method of performing mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with acid and electrochemical surface roughening treatment using different electrolytes a plurality of times on an aluminum plate,
However, the present invention is not limited to these. In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed.
As described above, the support for a lithographic printing plate of the present invention obtained by these methods has a structure in which three or more kinds of irregularities with different periods are superimposed on the surface. Excellent in both stain resistance and printing durability.
Hereinafter, each step of the surface treatment will be described in detail.
[0063]
<Mechanical roughening>
The present inventors use low-purity aluminum and increase the tensile strength to a predetermined value or more, thereby making it possible to generate deep pits more than before without specially limiting the conditions in the mechanical surface roughening treatment. The present invention has been completed. Therefore, in the mechanical surface roughening treatment, generally used methods and conditions can be selected, and the surface having irregularities with an average wavelength of 5 to 100 μm is cheaper than the electrochemical surface roughening treatment. Therefore, it is effective as a roughening treatment means of the present invention.
[0064]
Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used.
A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in Japanese Patent Application No. -55871 and Japanese Patent Application No. 4-204235 (Japanese Patent Laid-Open No. 6-024168) characterized in that the surface is elastic is also applicable.
[0065]
In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of repeatedly transferring using a transfer roll etched with fine irregularities, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, etc. may be used. it can. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded.
Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed.
In addition, as the mechanical surface roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used.
In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably performed before the electrochemical surface roughening treatment.
[0066]
Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.
The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is performed by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.
When using a roller brush, the flexural modulus is preferably 10,000 to 40,000 kg / cm.², More preferably 15,000-35,000 kg / cm²In addition, brush hair having a bristle waist strength of preferably 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.
[0067]
A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumicestone, silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. In particular, silica sand is preferable in terms of excellent roughening efficiency because it is harder and less likely to break than Pamiston.
The average particle diameter of the abrasive is preferably 3 to 50 μm, and more preferably 6 to 45 μm in terms of excellent surface roughening efficiency and a narrow graining pitch.
For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.
[0068]
As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.
[0069]
<Electrochemical roughening treatment>
In the electrochemical surface roughening treatment, an electrolytic solution used for the electrochemical surface roughening treatment using a normal alternating current can be used. Among them, the concavo-convex structure characteristic of the present invention can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid.
As the electrolytic surface roughening treatment in the present invention, it is preferable to perform the first and second electrolytic treatments with an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated to make the surface state uniform, and it is possible to obtain a uniform electrolytic surface during the subsequent electrolysis with an alternating waveform current. .
This electrolytic surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.
[0070]
Various electrolyzers and power sources have been proposed. U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used. Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-133638, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 And those described in JP-A No. 54-146234 and the like can also be used.
[0071]
As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600, 482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 can also be used.
[0072]
The concentration of the acidic solution is preferably 0.5 to 2.5% by mass, but it is particularly preferably 0.7 to 2.0% by mass in consideration of use in the smut removal treatment. Moreover, it is preferable that liquid temperature is 20-80 degreeC, and it is more preferable that it is 30-60 degreeC.
[0073]
An aqueous solution mainly composed of hydrochloric acid or nitric acid is an aqueous solution of hydrochloric acid or nitric acid having a concentration of 1 to 100 g / L, such as nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate, aluminum chloride, sodium chloride, ammonium chloride, At least one of the hydrochloric acid compounds having hydrochloric acid ions can be used by adding in a range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid or nitric acid as a main component. Preferably, a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of hydrochloric acid or nitric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L is preferably used.
Here, “mainly” means that the main component in the aqueous solution is contained in an amount of 30% by mass or more, preferably 50% by mass or more based on the total components added to the aqueous solution. Hereinafter, the same applies to other components.
[0074]
Further, by adding and using a compound capable of forming a complex with Cu, uniform graining is possible even for an aluminum plate containing a relatively large amount of Cu. Examples of the compound capable of forming a complex with Cu include ammonia; hydrogen atom of ammonia such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, cyclohexylamine, triethanolamine, triisopropanolamine, EDTA (ethylenediaminetetraacetic acid). And amines obtained by substituting with a hydrocarbon group (aliphatic, aromatic, etc.); metal carbonates such as sodium carbonate, potassium carbonate, potassium hydrogen carbonate and the like. In addition, ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, and ammonium carbonate are also included.
The temperature is preferably 10-60 ° C, more preferably 20-50 ° C.
[0075]
The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable. A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 0.3 to 3 msec. If it is less than 0.3 msec, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate tend to occur. When TP exceeds 3 msec, especially when a nitric acid electrolyte is used, it is easily affected by trace components in the electrolyte typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is performed. It becomes hard to be broken. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.
[0076]
A trapezoidal wave alternating current duty ratio of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum. A duty ratio of 1: 1 is preferable. A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. When the frequency is lower than 50 Hz, the carbon electrode of the main electrode is easily dissolved, and when the frequency is higher than 70 Hz, it is easily affected by an inductance component on the power supply circuit, and the power supply cost is increased.
[0077]
One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 3, the current ratio between the AC anode and cathode applied to the aluminum plate facing the main electrode is controlled to achieve uniform graining and to dissolve the carbon of the main electrode. In addition, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 is a main electrolytic cell, and 50 is an auxiliary anode cell. An anodic reaction that acts on the aluminum plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.
[0078]
As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.
[0079]
(Nitric acid electrolysis)
Pits having an average opening diameter of 0.5 to 5 μm can be formed by electrochemical surface roughening using an electrolytic solution mainly composed of nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm are also generated.
In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is 1 to 1000 C / dm.²Is preferably 50 to 300 C / dm.²It is more preferable that The current density at this time is 20 to 100 A / dm.²Is preferred.
Further, when a high concentration or high temperature nitric acid electrolytic solution is used, a small wave structure having an average opening diameter of 0.2 μm or less can be formed.
[0080]
(Hydrochloric acid electrolysis)
Since hydrochloric acid has a strong aluminum dissolving power, it is possible to form fine irregularities on the surface with only slight electrolysis. The fine irregularities have an average opening diameter of 0.01 to 0.20 μm and are uniformly generated on the entire surface of the aluminum plate. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is 1 to 100 C / dm.²It is preferable that it is 20-70 C / dm.²It is more preferable that The current density at this time is 20 to 50 A / dm.²Is preferred.
[0081]
In such an electrochemical surface roughening treatment with an electrolyte mainly composed of hydrochloric acid, the total amount of electricity involved in the anode reaction is set to 400 to 1000 C / dm.²It is possible to simultaneously form a large crater-like undulation by increasing the crater shape, but in this case, an average opening diameter of 0.01 to 0.4 μm is superimposed on the crater-like undulation having an average opening diameter of 10 to 30 μm. Fine irregularities are generated on the entire surface. Therefore, in this case, since the medium wave structure with an average opening diameter of 0.5 to 5 μm cannot be superimposed, the grain shape of the surface that is a feature of the present invention cannot be made.
[0082]
The aluminum plate is preferably subjected to cathodic electrolysis treatment during the first and second electrolytic surface-roughening treatments performed in the electrolytic solution such as nitric acid and hydrochloric acid. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic surface roughening treatment. The cathodic electrolysis is preferably performed in an acidic solution with a cathode electric quantity of 3 to 80 C / dm.², More preferably 5-30 C / dm²Done in Cathode electricity is 3 C / dm²If it is less than 80, the smut adhesion amount may be insufficient, and 80 C / dm.²If it exceeds 1, the amount of smut adhesion may become excessive, which is not preferable. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening processes.
[0083]
<Alkaline etching treatment>
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.
[0084]
Alkaline etching performed before the electrolytic surface roughening treatment removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) if mechanical surface roughening treatment is not performed. If the surface of the unevenness generated by the mechanical surface roughening treatment is dissolved, the surface with sharp undulations is smoothed. It is done for the purpose of changing.
[0085]
When the mechanical surface roughening treatment is not performed before the alkali etching treatment, the etching amount is 0.1 to 10 g / m.²1 to 5 g / m is preferable.²It is more preferable that Etching amount is 0.1g / m²If it is less than that, rolling oil, dirt, natural oxide film, etc. on the surface may remain, so that uniform pits cannot be generated in the subsequent electrolytic surface roughening treatment, and unevenness may occur. On the other hand, the etching amount is 1 to 10 g / m.²If it is, removal of rolling oil, dirt, natural oxide film, etc. on the surface is sufficiently performed. An etching amount exceeding the above range is economically disadvantageous.
[0086]
When mechanical roughening treatment is performed before the alkali etching treatment, the etching amount is 3 to 20 g / m.²Is preferably 5 to 15 g / m.²It is more preferable that Etching amount is 3g / m²If it is less than 1, the unevenness formed by mechanical surface roughening or the like may not be smoothed, and uniform pit formation may not be possible in the subsequent electrolytic treatment. In addition, the stain may deteriorate during printing. On the other hand, the etching amount is 20 g / m.²Exceeding may cause the concavo-convex structure to disappear.
[0087]
The alkali etching treatment performed immediately after the electrolytic surface roughening treatment is performed for the purpose of dissolving the smut generated in the acidic electrolytic solution and dissolving the edge portion of the pit formed by the electrolytic surface roughening treatment. .
Since the pits formed by the electrolytic surface roughening treatment are different depending on the type of the electrolytic solution, the optimum etching amount is also different, but the etching amount of the alkali etching treatment performed after the electrolytic surface roughening treatment is 0.1 to 5 g / m.²Is preferred. When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used.
When the electrolytic surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.
In addition, although it is not necessary to perform an alkali etching process immediately after an electrolytic surface roughening process, in this case, it may be inferior to stain resistance when using a lithographic printing plate.
[0088]
Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of the alkali metal salt include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.
[0089]
Although the density | concentration of an alkaline solution can be determined according to the etching amount, it is preferable that it is 1-50 mass%, and it is more preferable that it is 10-35 mass%. When aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90 ° C. The treatment time is preferably 1 to 120 seconds.
[0090]
Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.
[0091]
<Desmut treatment>
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
The desmutting treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include, for example, a method of passing the aluminum plate through a bath containing the acidic solution, a method of immersing the aluminum plate in a bath containing the acidic solution, and an acidic solution containing aluminum. The method of spraying on the surface of a board is mentioned.
In the desmutting treatment, the acidic solution is mainly composed of an aqueous solution mainly composed of nitric acid or an aqueous solution mainly composed of hydrochloric acid discharged in the above-described electrolytic surface-roughening treatment, or sulfuric acid discharged in an anodic oxidation process described later. It is possible to use a waste solution of an aqueous solution.
It is preferable that the liquid temperature of a desmut process is 25-90 degreeC. Moreover, it is preferable that processing time is 1-180 second. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.
[0092]
<Anodizing treatment>
The aluminum plate treated as described above is further subjected to anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.
[0093]
Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cations such as ammonium ion; anions such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10000 ppm It may be contained at a concentration of about.
[0094]
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ~ 60A / dm²It is appropriate that the voltage is 1 to 100 V and the electrolysis time is 15 seconds to 50 minutes.
[0095]
Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.
[0096]
Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), and the aluminum ion concentration is 1 to 25 g / L (0.1 to 2.5% by mass). It is preferable that it is 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.
[0097]
When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied.
When direct current is applied to the aluminum plate, the current density is 1 to 60 A / dm.²Is preferably 5 to 40 A / dm.²It is more preferable that
In the case of continuously performing anodizing treatment, 5-10 A / m at the beginning of the anodizing treatment so that current is concentrated on a part of the aluminum plate and so-called “burn” does not occur.²30 to 50 A / dm as the anodizing process proceeds at a low current density of²Alternatively, it is preferable to increase the current density further.
When the anodizing treatment is continuously performed, it is preferable that the anodizing process is performed by a liquid power feeding method in which power is supplied to the aluminum plate through an electrolytic solution.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ~ 800 / μm²Degree.
[0098]
The amount of anodized film is 1-5g / m²Is preferred. 1g / m²If it is less than 5%, the plate is likely to be damaged, while 5 g / m.²Exceeding this requires a large amount of power for production, which is economically disadvantageous. The amount of anodized film is 1.5-4 g / m²It is more preferable that Further, the difference in the amount of the anodized film between the center portion of the aluminum plate and the vicinity of the edge portion is 1 g / m.²It is preferable to carry out as follows.
[0099]
As the electrolysis apparatus used for the anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, and the like can be used.
Among these, the apparatus shown in FIG. 4 is preferably used. FIG. 4 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum plate. In the anodizing apparatus 410, the aluminum plate 416 is transported as indicated by arrows in FIG. In the power supply tank 412 in which the electrolytic solution 418 is stored, the aluminum plate 416 is charged to (+) by the power supply electrode 420. The aluminum plate 416 is conveyed upward by the roller 422 in the power supply tank 412, changed in direction downward by the nip roller 424, and then conveyed toward the electrolytic treatment tank 414 in which the electrolytic solution 426 is stored. The direction is changed horizontally. Next, the aluminum plate 416 is charged to (−) by the electrolytic electrode 430 to form an anodized film on the surface thereof, and the aluminum plate 416 exiting the electrolytic treatment tank 414 is conveyed to a subsequent process. In the anodizing apparatus 410, the roller 422, the nip roller 424, and the roller 428 constitute a direction changing means, and the aluminum plate 416 is disposed between the power supply tank 412 and the electrolytic treatment tank 414 in the inter-tank section. By 428, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 420 and the electrolytic electrode 430 are connected to a DC power source 434.
[0100]
A feature of the anodizing apparatus 410 in FIG. 4 is that the feeding tank 412 and the electrolytic treatment tank 414 are partitioned by a single tank wall 432, and the aluminum plate 416 is conveyed in a mountain shape and an inverted U shape between the tanks. It is in. As a result, the length of the aluminum plate 416 in the inter-tank portion can be minimized. Therefore, the overall length of the anodizing apparatus 410 can be shortened, so that the equipment cost can be reduced. In addition, by conveying the aluminum plate 416 in a mountain shape and an inverted U shape, it is not necessary to form an opening for allowing the aluminum plate 416 to pass through the tank walls of the tanks 412 and 414. Therefore, since the liquid feeding amount required to maintain the liquid level height in each tank 412 and 414 at a required level can be suppressed, the operating cost can be reduced.
[0101]
<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, Japanese Patent Publication No. 56-12518, Japanese Patent Application Laid-Open No. 4-4194, Japanese Patent Application No. 4-33952 (Japanese Patent Application Laid-Open No. 5-202496), Japanese Patent Application No. 4-33951 (Japanese Patent Application Laid-Open No. -179482) etc. may be used for sealing treatment.
[0102]
<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorinated zirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinyl phosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a subbing layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.
[0103]
Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids.
Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.
[0104]
Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. It is preferable to carry out the treatment.
[0105]
Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures.
Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.
[0106]
The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is about 1.0 to 15.0 mg / m.²Is preferred.
By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.
[0107]
The hydrophilization treatment by forming a hydrophilic undercoat layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491.
Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, sulfo group-containing vinyl polymerizable compounds such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Moreover, as a hydrophilic compound used for this method, for example, —NH₂And a compound having at least one selected from the group consisting of a group, a —COOH group and a sulfo group.
[0108]
<Washing treatment>
It is preferable to perform water washing after the completion of the above-described processes. For washing, pure water, well water, tap water, or the like can be used. A nip device may be used to prevent the processing liquid from being brought into the next process.
[0109]
[Lithographic printing plate precursor]
Next, the planographic printing plate precursor of the present invention will be described. The lithographic printing plate precursor according to the invention comprises an image recording layer provided on the lithographic printing plate support according to the invention.
[0110]
<Undercoat layer>
In the lithographic printing plate precursor according to the present invention, before providing an image recording layer on the lithographic printing plate support of the present invention obtained as described above, if necessary, for example, zinc borate or the like. An inorganic undercoat layer such as a water-soluble metal salt or an organic undercoat layer may be provided.
[0111]
Examples of the organic compound used in the organic undercoat layer include carboxymethyl cellulose; dextrin; gum arabic; polymers and copolymers having a sulfonic acid group in the side chain; polyacrylic acid; amino such as 2-aminoethylphosphonic acid Phosphonic acids having a group; phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid, ethylenediphosphonic acid, etc., which may have a substituent; Organic phosphoric acid such as phenylphosphonic acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid which may be substituted; phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid, etc. which may have a substituent Organic phosphinic acids; amino acids such as glycine and β-alanine Amine hydrochloride having hydroxy group such as triethanolamine hydrochloride; and the yellow dye. These may be used alone or in combination of two or more.
[0112]
The organic undercoat layer is provided by applying a solution obtained by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof on an aluminum plate and drying it. The concentration of the solution in which the organic compound is dissolved is preferably 0.005 to 10% by mass. The coating method is not particularly limited, and any method such as bar coater coating, spin coating, spray coating, curtain coating and the like can be used.
The coating amount of the organic undercoat layer after drying is 2 to 200 mg / m²Is preferably 5 to 100 mg / m²It is more preferable that When it is in the above range, the printing durability becomes better.
[0113]
<Image recording layer>
The lithographic printing plate support of the present invention can be provided with an image recording layer such as a photosensitive layer and a heat-sensitive layer exemplified below to form the lithographic printing plate precursor of the present invention. Suitable examples of the image recording layer include a conventional positive type, a conventional negative type, a photopolymer type, a thermal positive type, a thermal negative type, and an unprocessable type that can be developed on the machine. Hereinafter, these suitable image recording layers will be described.
[0114]
<Conventional positive type>
Examples of the photosensitive resin composition suitably used for the conventional positive type photosensitive layer include an o-quinonediazide compound and a water-insoluble and alkali-soluble polymer compound (hereinafter referred to as “alkali-soluble polymer compound”). The composition to contain is mentioned.
Examples of o-quinonediazide compounds include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, and US Pat. No. 3,635,709. Examples include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol / acetone resin as described.
Examples of the alkali-soluble polymer compound include phenol / formaldehyde resin, cresol / formaldehyde resin, phenol / cresol / formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, Carboxy group-containing polymers described in JP-A-7-36184, acrylic resins containing phenolic hydroxy groups as described in JP-A-51-34711, and JP-A-2-866. Examples thereof include acrylic resins having sulfonamide groups and urethane resins.
Further, in the photosensitive resin composition, compounds such as a sensitivity adjusting agent, a baking agent, and a dye described in [0024] to [0027] of JP-A-7-92660 and [0031] of the same publication. It is preferable to add a surfactant for improving the coating property.
[0115]
<Conventional negative type>
Examples of the photosensitive resin composition suitably used for the conventional negative type photosensitive layer include a composition containing a diazo resin and an alkali-soluble or swellable polymer compound (hereinafter referred to as “binder”).
Examples of the diazo resin include a condensate of an aromatic diazonium salt and an active carbonyl group-containing compound such as formaldehyde, a condensate of p-diazophenylamines and formaldehyde, and a hexafluorophosphate or a tetrafluoroborate. Organic solvent-soluble diazo resin inorganic salts which are reaction products of In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable.
Suitable binders include, for example, a copolymer containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as an essential component, specifically 2 as described in JP-A-50-118802. -Multi-component copolymers of monomers such as hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylic acid, alkyl acrylates as described in JP-A-56-4144, (meth) acrylonitrile And multi-component copolymers composed of unsaturated carboxylic acids.
Furthermore, plastics for imparting flexibility and abrasion resistance to the photosensitive resin composition described in JP-A-7-281425, [0014] to [0015]. It is preferable to add a compound such as an agent and a development accelerator and a surfactant for improving the coating property.
As an undercoat layer of the conventional positive or negative photosensitive layer, a polymer having a component having an acid group and a component having an onium group as described in JP-A-2000-105462. An intermediate layer containing the compound is preferably provided.
[0116]
<Photopolymer type>
A photopolymerization type photosensitive composition (hereinafter referred to as “photopolymerizable composition”) suitably used for a photopolymer type photosensitive layer is an addition-polymerizable ethylenically unsaturated bond-containing compound (hereinafter simply referred to as “ethylene”). ), A photopolymerization initiator, and a polymer binder as essential components, and if necessary, various compounds such as a colorant, a plasticizer, and a thermal polymerization inhibitor. Containing.
The ethylenically unsaturated bond-containing compound contained in the photopolymerizable composition is such that, when the photopolymerizable composition is irradiated with actinic rays, it undergoes addition polymerization by the action of the photopolymerization initiator, crosslinks and cures. It is a compound having an ethylenically unsaturated bond. The ethylenically unsaturated bond-containing compound can be arbitrarily selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more, such as monomers, prepolymers (ie, dimers). Trimers and oligomers), mixtures thereof, and copolymers thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic polyhydric compounds. And amides with a polyvalent amine compound. Urethane addition polymerizable compounds are also suitable.
[0117]
As the photopolymerization initiator contained in the photopolymerizable composition, various photopolymerization initiators or a combination system (photoinitiation system) of two or more photopolymerization initiators are appropriately selected depending on the wavelength of the light source used. For example, an initiation system described in JP-A-2001-22079, [0021] to [0023] is preferable.
The polymer binder contained in the photopolymerizable composition not only functions as a film-forming agent for the photopolymerizable composition, but also needs to dissolve the photosensitive layer in an alkali developer. An organic high molecular weight polymer that is swellable is used. As the polymer binder, those described in [0036] to [0063] of the same publication are useful.
It is preferable to add the additive (for example, surfactant for improving applicability | paintability) described in [0079]-[0088] of the same gazette to the photopolymerizable composition. Further, it is preferable to provide an oxygen-blocking protective layer on the photosensitive layer in order to prevent the oxygen polymerization inhibiting action. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and copolymers thereof.
Furthermore, it is also preferable to provide an adhesive layer as described in [0131] to [0165] of JP-A-2001-228608 as the undercoat layer of the photosensitive layer.
[0118]
<Thermal positive type>
The thermal positive type heat-sensitive layer contains an alkali-soluble polymer compound and a photothermal conversion substance.
Alkali-soluble polymer compounds include homopolymers containing acidic groups in the polymer, copolymers thereof, and mixtures thereof, in particular, (1) phenolic hydroxy groups (—Ar—OH), (2) Sulfonamide group (—SO₂Those having an acidic group such as NH-R) are preferred from the viewpoint of solubility in an alkali developer. In particular, it is preferable to have a phenolic hydroxy group from the viewpoint of excellent image formability upon exposure with an infrared laser or the like. For example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) may be mixed Preferred are novolak resins such as formaldehyde resin; pyrogallol acetone resin. More specifically, the polymers described in [0023] to [0042] of JP-A No. 2001-305722 are preferably used.
[0119]
The photothermal conversion substance converts exposure energy into heat and can efficiently cancel the interaction of the exposed area of the heat sensitive layer. From the viewpoint of recording sensitivity, a pigment or dye having a light absorption region in the infrared region with a wavelength of 700 to 1200 nm is preferable. Specific examples of the dye include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolates. Complex (for example, nickel thiolate complex) etc. are mentioned. Among these, cyanine dyes are preferable, and examples thereof include cyanine dyes represented by general formula (I) in JP-A No. 2001-305722.
In the composition used for the thermal positive type heat-sensitive layer, the same sensitivity control agent, bake-out agent, dye, etc. as those described in the conventional positive type, and a surfactant for improving coating properties are added. It is preferable to add. Specifically, the compounds described in [0053] to [0059] of JP-A No. 2001-305722 are preferable.
The thermal positive type heat-sensitive layer may be a single layer or may have a two-layer structure as described in JP-A-11-218914.
An undercoat layer is preferably provided between the thermal positive type heat-sensitive layer and the support. Examples of components contained in the undercoat layer include various organic compounds described in JP-A-2001-305722, [0068].
[0120]
<Thermal negative type>
The thermal negative-type heat-sensitive layer is a negative-type heat-sensitive layer in which the infrared laser irradiation part is cured to form an image part.
A preferred example of such a thermal negative type heat-sensitive layer is a polymerization type layer (polymerization layer). The polymerization layer comprises (A) an infrared absorber, (B) a radical generator (radical polymerization initiator), a curing reaction caused by the generated radical (C) a radical polymerizable compound, and (D) a binder. Containing polymer.
In the polymerization layer, the infrared rays absorbed by the infrared absorber are converted into heat, and the generated heat decomposes radical polymerization initiators such as onium salts to generate radicals. The radically polymerizable compound is selected from compounds having a terminal ethylenically unsaturated bond, and a polymerization reaction is caused in a chain by the generated radicals and is cured.
Examples of (A) infrared absorbers include the above-described photothermal conversion substances contained in the above-described thermal positive type heat-sensitive layer. In particular, specific examples of cyanine dyes are disclosed in JP-A No. 2001-133969. To [0019], and (B) radical generators include onium salts. Specific examples of onium salts that can be suitably used include those described in JP-A-2001-133969. The compounds described in [0030] to [0033] are mentioned, and the (C) radical polymerizable compound is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. (D) It is preferable to use a linear organic polymer as the binder polymer, and a linear organic polymer that is soluble or swellable in water or weak alkaline water is selected. Of these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxy group in the side chain is particularly preferable because of its excellent balance of film strength, sensitivity, and developability. Regarding (C) the radical polymerizable compound and (D) the binder polymer, those described in detail in [0036] to [0060] of the same publication can be used. As other additives, it is also preferable to add the additives described in [0061] to [0068] of the same publication (for example, a surfactant for improving coatability).
[0121]
In addition to the polymerization type, an acid cross-linked layer (acid cross-linked layer) is preferably used as one of the thermal negative type heat-sensitive layers. The acid cross-linking layer includes (E) a compound that generates an acid by light or heat (hereinafter referred to as “acid generator”) and (F) a compound that cross-links by the generated acid (hereinafter referred to as “cross-linking agent”). And (G) an alkali-soluble polymer compound that can react with a crosslinking agent in the presence of an acid. In order to efficiently use the energy of the infrared laser, (A) an infrared absorber is blended in the acid crosslinking layer. Examples of the acid generator (E) include compounds capable of generating an acid upon thermal decomposition, such as a photoinitiator for photopolymerization, a photochromic agent for dyes, and an acid generator used for a microresist. . (F) As the crosslinking agent, (i) an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group, (ii) a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group, (Iii) An epoxy compound is mentioned. (G) Examples of the alkali-soluble polymer compound include novolak resins and polymers having a hydroxyaryl group in the side chain.
[0122]
<Non-treatment type>
Non-treatment type heat-sensitive layers include thermoplastic fine particle polymer type, microcapsule type, and sulfonic acid-generating polymer-containing type.
In the thermoplastic fine particle polymer type, (H) hydrophobic hot-melt resin fine particles are dispersed in (J) a hydrophilic polymer matrix, and the hydrophobic polymer is melted by the heat of the exposed area and fused to each other. To form a hydrophobic region, that is, an image portion.
(H) Hydrophobic heat-meltable resin fine particles (hereinafter referred to as “fine-particle polymer”) are preferably those in which fine-particle polymers are melted and coalesced by heat, have a hydrophilic surface, and are used as hydrophilic components such as dampening water. Dispersed particulate polymers having a hydrophilic surface are preferred. As the fine particle polymer, Research Disclosure No. 33303 (January 1992), JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, and European Patent Application Publication No. 931,647. Preferred examples thereof include thermoplastic fine particle polymers. Specific examples include homopolymers or copolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or mixtures thereof. . Of these, polystyrene and polymethyl methacrylate are preferably used. The fine particle polymer having a hydrophilic surface is such that the polymer itself constituting the fine particle is hydrophilic, or the polymer itself is hydrophilic, such as those obtained by introducing a hydrophilic group into the main chain or side chain of the polymer. A hydrophilic polymer such as polyvinyl alcohol or polyethylene glycol, a hydrophilic oligomer or a hydrophilic low molecular weight compound is adsorbed on the surface of the fine particle polymer to make the surface hydrophilic. As the fine particle polymer, a fine particle polymer having a thermally reactive functional group is more preferable. When the fine particle polymer as described above is dispersed in the (J) hydrophilic polymer matrix, the on-press development property is improved when the on-press development is performed, and the film strength of the thermosensitive layer itself is also improved.
[0123]
Examples of the microcapsule type include a type described in JP-A No. 2000-118160 and a microcapsule type containing a compound having a thermally reactive functional group as described in JP-A No. 2001-277740. Preferably mentioned.
Examples of the sulfonic acid generating polymer used in the sulfonic acid generating polymer-containing type include, for example, a sulfonic acid ester group, a disulfone group, or a sec- or tert-sulfonamide group described in JP-A-10-282672 as a side chain. The polymer etc. which have are mentioned.
By including a hydrophilic resin in the untreated type heat-sensitive layer, not only the on-press developability is improved, but also the film strength of the heat-sensitive layer itself is improved. In addition, a lithographic printing plate precursor that does not require development processing can be obtained by crosslinking and curing the hydrophilic resin. Examples of the hydrophilic resin include those having a hydrophilic group such as hydroxy group, carboxy group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group, and hydrophilic sol-gel conversion. A system binder resin is preferred. Specific examples of the hydrophilic resin include those listed as the hydrophilic resin used as the above-mentioned (J) hydrophilic polymer matrix.
Among these, a sol-gel conversion binder resin is preferable.
It is necessary to add a photothermal conversion substance to the untreated type heat-sensitive layer. The photothermal conversion substance may be any substance that absorbs light having a wavelength of 700 nm or more, and a dye similar to the dye used for the above-described thermal positive type is particularly preferable.
[0124]
<Back coat layer>
Thus, the image recording layer in the case where the lithographic printing plate is overlaid on the back surface of the lithographic printing plate precursor obtained by providing various image recording layers on the lithographic printing plate support, if necessary. In order to prevent scratching, a backcoat layer made of an organic polymer compound can be provided.
[0125]
<Application method>
As a method of applying the conventional type, photopolymer type, thermal type, and non-processing type image recording layer forming liquid to the roughened surface of the lithographic printing plate support, a method using a coating rod, an extrusion type Conventionally known methods such as a method using a coater and a method using a slide bead coater can be used, and can be performed according to known conditions.
[0126]
As an apparatus for drying the aluminum plate after applying the conventional type, photopolymer type, thermal type, and non-processing type image recording layer forming liquid, a pass roll is provided in the drying apparatus described in JP-A-6-63487. An arch dryer that is dried while being conveyed by the pass roll, an air dryer that supplies air from above and below by a nozzle, and dries while floating the web, a radiant heat dryer that is dried by radiant heat from a medium heated to a high temperature, In addition, there is a roller dryer that heats the roller and dries by conduction heat transfer by contact with the roller.
[0127]
[Lithographic printing plate]
The lithographic printing plate precursor according to the invention is made into a lithographic printing plate by various processing methods according to the image recording layer.
In general, image exposure is performed. Examples of the actinic ray light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include a helium-neon laser (He-Ne laser), an argon laser, a krypton laser, a helium-cadmium laser, a KrF excimer laser, a semiconductor laser, a YAG laser, and a YAG-SHG laser.
After the exposure, when the image recording layer is any one of a thermal type, a conventional type, and a photopolymer type, it is preferable to develop with a developer and obtain a lithographic printing plate after the exposure. The preferred developer used for the lithographic printing plate precursor is not particularly limited as long as it is an alkaline developer, but an alkaline aqueous solution substantially not containing an organic solvent is preferred. Moreover, it can also develop using the developing solution which does not contain alkali metal silicate substantially. About the method of developing using the developing solution which does not contain alkali metal silicate substantially, it describes in Unexamined-Japanese-Patent No. 11-109637 in detail, The content described in this gazette can be used. . Moreover, the lithographic printing plate precursor can be developed using a developer containing an alkali metal silicate.
[0128]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
(Examples 1-5 and Comparative Examples 1-29)
1. Making a support for planographic printing plates
<Aluminum plate>
The metal components shown in Table 1 below are contained, and the balance is prepared by using Al and an inevitable impurity aluminum alloy, and after performing the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is converted into DC. Made by casting. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Further, after heat treatment was performed at 500 ° C. using a continuous annealing machine, the thickness was finished to 0.24 mm by cold rolling. In the final rolling, the aluminum plate AL1 to AL7 shown in Table 1 was obtained by changing the rolling reduction to adjust the strength of the aluminum plate. The density of intermetallic compounds existing within 2 μm from the surface layer of each aluminum plate was determined by the following method.
[0129]
Each aluminum plate was subjected to surface analysis in the range of 170 μm × 170 μm using EPMA (Electron Probe Microanalyzer) to count intermetallic compounds, and 1 mm²The density of the intermetallic compound existing within 2 μm from the surface layer was determined by converting to the per unit. The results are shown in Table 1.
[0130]
Moreover, about each aluminum plate, the tensile strength was measured as follows. The results are shown in Table 1.
Using an autograph (trade name) manufactured by Shimadzu Corporation, a tensile strength in the plate rolling direction was measured using a sample having a width of 25 mm.
[0131]
[Table 1]

[0132]
Surface treatments A to E shown below were applied to the aluminum plates AL1 to AL7 in the combinations shown in Table 2 to obtain a lithographic printing plate support.
[0133]
<Surface treatment A>
Surface treatment A was performed by continuously performing the various treatments shown below. In addition, after each process and water washing, the liquid was drained with the nip roller.
[0134]
(A) Mechanical roughening treatment
Using an apparatus as shown in FIG. 1, while rotating a suspension (specific gravity 1.12) of a polishing agent (pumice, average particle size 30 μm) and water as a polishing slurry liquid on the surface of the aluminum plate, rotation The surface was mechanically roughened with a roller nylon brush. In FIG. 1, 1 is an aluminum plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers. The average particle size of the abrasive was 30 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.48 mm. Nylon brush was planted so as to be dense by making a hole in a stainless steel cylinder of φ300 mm (the brush hair density was 450 / cm²Met. ). Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.
[0135]
(B) Alkali etching treatment
The aluminum plate obtained above was subjected to an etching process by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C.²Dissolved. Then, water washing by spraying was performed.
[0136]
(C) Desmut treatment
A desmut treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.
[0137]
(D) Electrochemical roughening treatment
An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 3 was used.
The current density is 30 A / dm at the peak current value.²The amount of electricity is 220 C / dm in terms of the total amount of electricity when the aluminum plate is the anode.²Met. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.
[0138]
(E) Alkali etching treatment
The aluminum plate was etched by spraying at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was 0.25 g / m.²Dissolve and remove the smut component mainly composed of aluminum hydroxide that was generated when the electrochemical roughening treatment was performed using the alternating current of the previous stage, and the edge portion of the generated pit was dissolved Made smooth. Then, water washing by spraying was performed.
[0139]
(F) Desmut treatment
The desmutting treatment was performed by spraying with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.
[0140]
(G) Electrochemical roughening treatment
An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 3 was used.
The current density is 25 A / dm at the peak current value.²The amount of electricity is 50 C / dm as the total amount of electricity when the aluminum plate is the anode.²Met.
Then, water washing by spraying was performed.
[0141]
(H) Alkali etching treatment
The aluminum plate was etched by spraying at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was 0.10 g / m.²Dissolve and remove the smut component mainly composed of aluminum hydroxide that was generated when the electrochemical roughening treatment was performed using the alternating current of the previous stage, and the edge portion of the generated pit was dissolved Made smooth. Then, water washing by spraying was performed.
[0142]
(I) Desmut treatment
The desmutting treatment was performed by spraying with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), and then washing with water by spraying.
[0143]
(J) Anodizing treatment
Anodization was performed using the anodizing apparatus having the structure shown in FIG. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount is 2.7 g / m²Met.
[0144]
<Surface treatment B>
In the (h) alkali etching treatment of the surface treatment A, the dissolution amount of the aluminum plate is 1.0 g / m.²A surface treatment was performed in the same manner as in the surface treatment A except that.
[0145]
<Surface treatment C>
Surface treatment was performed in the same manner as surface treatment A, except that (g), (h), and (i) of surface treatment A were not performed.
[0146]
<Surface treatment D>
The surface treatment A (a), (d), (e), (f) is not performed. In the surface treatment A (g), the total amount of electricity when the aluminum plate is an anode is 1200 C / dm.²A surface treatment was performed in the same manner as in the surface treatment A except that.
[0147]
<Surface treatment E>
Surface treatment was performed in the same manner as surface treatment A except that (a), (g), (h), and (i) of surface treatment A were not performed.
[0148]
2. Measurement of surface shape of lithographic printing plate support
The following measurements (1) to (4) were performed on the concave portions on the surface of the lithographic printing plate support obtained above.
The results are shown in Table 2. In Table 2, "-" indicates that there was no recess having the corresponding average wavelength or average aperture diameter.
[0149]
(1) Average opening diameter of medium wave structure
Using the SEM, the surface of the support was photographed at a magnification of 2000 times from directly above, and 50 pits (medium pits) having a medium wave structure in which the periphery of the pit was connected in a ring shape were extracted from the obtained SEM photograph. The diameter was read and used as the opening diameter, and the average opening diameter was calculated.
[0150]
(2) Average aperture diameter of small wave structure
The surface of the support was photographed at a magnification of 50000 times from directly above using a high-resolution SEM, 50 small-wave structure pits (small-wave pits) were extracted from the obtained SEM photograph, and the diameter was read as the opening diameter. The average opening diameter was calculated.
[0151]
(3) Average ratio of depth to aperture diameter of small wave structure
The average ratio of the depth to the aperture diameter of the small wave structure was obtained by photographing the fracture surface of the support at a magnification of 50000 times using a high-resolution SEM, and in the obtained SEM photograph, 20 small-wave pits having an aperture diameter of 0.3 μm or less. Each sample was extracted, the aperture diameter and depth were read, the ratio was determined, and the average value was calculated.
[0152]
(4) Average wavelength of large wave structure
Two-dimensional roughness measurement is performed with a stylus type roughness meter (SUFCOM 575, manufactured by Tokyo Seimitsu Co., Ltd.), and the average mountain interval S defined in ISO 4287 is measured._mWas measured five times, and the average value was defined as the average wavelength. Two-dimensional roughness measurement was performed under the following conditions.
Cut off 0.8, tilt correction FLAT-ML, measurement length 3 mm, longitudinal magnification 10000 times, scanning speed 0.3 mm / sec, stylus tip diameter 2 μm.
[0153]
[Table 2]

[0154]
[Table 3]

[0155]
3. Creating a lithographic printing plate precursor
Each of the lithographic printing plate supports obtained above was provided with the following image recording layers I to III to obtain a lithographic printing plate precursor.
In addition, before providing the image recording layers I to III, the following hydrophilic treatment by an alkali metal silicate treatment and an interface treatment of an undercoat treatment were performed.
[0156]
The lithographic printing plate support obtained above is immersed in a treatment tank of a 1% by weight aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds, whereby an alkali metal silicate treatment (silicate treatment). Went. Then, the water washing by the spray using well water was performed.
On the lithographic printing plate support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds to form a coating film. The coating amount of the coating after drying is 10 mg / m²Met.
[0157]
<Undercoat liquid composition>
・ The following polymer compound 0.2g
・ Methanol 100g
・ Water 1g
[0158]
[Chemical 1]

[0159]
<Image recording layer I>
A heat-sensitive layer coating solution having the following composition was prepared, and the coating amount (heat-sensitive layer coating amount) after drying the heat-sensitive layer coating solution on a lithographic printing plate support that was undercoated was 1.7 g / m.²And dried to form a heat-sensitive layer to obtain a lithographic printing plate precursor.
[0160]
(Thermosensitive layer coating solution composition)
・ Novolak resin (m-cresol / p-cresol = 60/40, weight average molecular weight 7,000, containing 0.5% by mass of unreacted cresol) 1.0 g
・ Cyanine dye A represented by the following structural formula 0.1 g
・ Tetrahydrophthalic anhydride 0.05g
・ P-Toluenesulfonic acid 0.002g
-Ethyl violet counter ion with 6-hydroxy-β-naphthalenesulfonic acid 0.02g
-Fluorosurfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.) 0.05g
・ Methyl ethyl ketone 12g
[0161]
[Chemical 2]

[0162]
<Image recording layer II>
On the undercoated lithographic printing plate support, a photosensitive solution having the following composition was applied using a bar and dried at 120 ° C. for 40 seconds to form a photosensitive layer. The weight of the photosensitive layer after drying is 1.0 g / m.²Met.
(Photosensitive solution composition)

[0163]
[Chemical 3]

[0164]
On the photosensitive layer thus provided, a mat solution having the following composition was sprayed and applied by electrostatic spraying, dried at 60 ° C. for 5 seconds to adhere the mat to the surface, and a lithographic printing plate precursor was obtained.
The number of droplets is 50-100 / mm²The mat weight after drying is 0.05 g / m.²The height was 2 to 6 μm and the diameter was 20 to 150 μm.
(Matte liquid composition)
-Sodium 2-acrylamido-2-methylpropanoate / ethyl acrylate / methyl methacrylate = 15/15/70 (molar ratio) copolymer (weight average molecular weight 100,000) 20.0 g
・ Tartrazine (water-soluble dye) 0. 1g
・ Pure water 79.9g
[0165]
<Image recording layer III>
On the undercoated lithographic printing plate support, first, an intermediate layer solution having the following composition was applied using a bar and dried at 80 ° C. for 20 seconds to provide an intermediate layer. The coating weight of the intermediate layer after drying is 0.005 g / m²Met.
(Interlayer liquid composition)
・ Copolymer of sodium 2-acrylamido-2-methylpropanoate / ethyl acrylate / methyl acrylate = 20/30/50 (molar ratio) (weight average molecular weight 70,000) 1.0 g
・ Methanol 90.0g
・ Pure 9.0g
[0166]
Next, a photosensitive solution having the following composition was applied using a bar and dried at 130 ° C. for 40 seconds to provide a photosensitive layer. The weight of the intermediate layer after drying is 1.5 g / m²Met.
(Photosensitive solution composition)
・ 4,4′-diphenylmethane diisocyanate / hexamethylene diisocyanate / 2,2-bis (hydroxymethyl) propionic acid / tetraethylene glycol = 40/10/35/15 (molar ratio) urethane resin (weight average molecular weight 100,000) 2.5g
-Copolymer of methacrylic acid / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylonitrile = 5/35/40/20 (molar ratio) (weight average molecular weight 80,000) 2.5 g
・ Dodecylbenzenesulfonate (diazo resin), a condensate of 4-diazodiphenylamine and formaldehyde, 1.2 g
・ Styrene / maleic anhydride = 50/50 (molar ratio) copolymer (weight average molecular weight 30,000) half ester of n-hexyl alcohol 0.1 g
・ Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 15g
・ Megafac F-176PF (Dainippon Ink & Chemicals, Inc. fluorine-based surface active
Sex agent) 0. 1g
・ Tricresyl phosphate 0.15 g
・ Phosphorous acid 0.02g
・ Malic acid 0.02g
・ Propylene glycol monomethyl ether 40g
・ Methyl ethyl ketone 30g
・ Methanol 20g
・ Methyl lactate 10g
・ Pure water 1.5g
[0167]
On the photosensitive layer thus provided, a mat solution having the following composition was sprayed and applied by electrostatic spraying, dried at 60 ° C. for 5 seconds to adhere the mat to the surface, and a lithographic printing plate precursor was obtained.
The number of droplets is 50 to 150 / mm²The mat weight after drying is 0.10 g / m.²The height was 2 to 6 μm and the diameter was 20 to 150 μm.
(Matte liquid composition)
-Sodium 2-acrylamido-2-methylpropanoate / ethyl acrylate / methyl methacrylate = 15/15/70 (molar ratio) copolymer (weight average molecular weight 100,000) 20.0 g
・ Tartrazine (water-soluble dye) 0. 1g
・ Pure water 79.9g
[0168]
4). Exposure and development processing
Each lithographic printing plate precursor provided with the image recording layers I to III obtained above was subjected to image exposure and development treatment according to the following method in accordance with the image recording layer to obtain a lithographic printing plate.
[0169]
<Lithographic printing plate precursor provided with image recording layer I>
A lithographic printing plate precursor provided with the image recording layer I has an output of 500 mW, a wavelength of 830 nm, a beam diameter of 17 μm (1 / e²) Using a TrendSetter 3244 manufactured by CREO equipped with a semiconductor laser, a main scanning speed of 5 m / sec, and a plate surface energy amount of 140 mJ / cm.²And imagewise exposure. In addition, in order to evaluate the presence or absence of the generation of a pot-like residual film described later, the plate surface energy amount is 20 to 140 mJ / cm.²Up to 20 mJ / cm²Samples subjected to exposure at different intervals were prepared.
Thereafter, D-sorbite / potassium oxide K, which is a combination of a non-reducing sugar and a base₂Development processing was performed using an alkaline developer in which the following compound a was added to 1 L of an aqueous solution containing 5.0% by mass of a potassium salt of O and 0.015% by mass of Olphine AK-02 (manufactured by Nissin Chemical). . The development process was carried out using an automatic processor PS900NP (Fuji Photo Film Co., Ltd.) filled with the above alkaline developer under the conditions of a development temperature of 25 ° C. and 12 seconds. After completion of the development treatment, a lithographic printing plate in which plate making was completed was obtained through a water washing step and treatment with a gum (GU-7 (1: 1)). In addition, even if it was a case where the alkaline developing solution which added the following compound b or c by the same addition amount instead of the compound a was used, it was able to develop similarly.
<Compounds a to c>
Compound a: C₁₂H₂₅N (CH₂CH₂COONa)₂
Compound b: C₁₂H₂₅O (CH₂CH₂O)₇H
Compound c: (C₆H₁₃)₂CHO (CH₂CH₂O)₂₀H
[0170]
<Lithographic printing plate precursor provided with image recording layer II>
A halftone dot negative film was superimposed on the lithographic printing plate precursor provided with the image recording layer II, and exposed for 200 counts with a printer FT26V2UPNS (light source; 2 KW metal halide lamp) manufactured by Nuark, USA. In addition, in order to evaluate the presence or absence of the occurrence of a pot-like residual film, which will be described later, a sample was prepared by changing the count number from 100 to 200 counts every 10 counts.
Thereafter, development processing and application of a gum solution were performed using an automatic developing machine 900NP manufactured by Fuji Photo Film Co., Ltd. At that time, a developing solution having the following composition was used as the developing solution, and a gum solution having the following composition was used as the gum solution. The temperature of the developer was 30 ° C., and the conveyance speed was adjusted so that the penetration time into the developer was 12 seconds.
[0171]
(Developer composition)
・ [SiO₂] / [K₂The molar ratio of O] is 1. 2 、 SiO₂Concentration is 2. 1 mass% potassium silicate aqueous solution 999 g
-Disodium salt of ethylenediaminetetraacetic acid 1g
(Gum solution composition)
-Arabic gum 5. 0g
・ White dextrin 30g
・ Ethylene glycol 10g
・ Phosphoric acid 3g
・ Water 952g
[0172]
<Lithographic printing plate precursor provided with image recording layer III>
A halftone dot negative film was superimposed on the lithographic printing plate precursor provided with the image recording layer II, and exposed for 200 counts with a printer FT26V2UPNS (light source; 2 KW metal halide lamp) manufactured by Nuark, USA. In addition, in order to evaluate the presence or absence of the occurrence of a pot-like residual film, which will be described later, a sample was prepared by changing the count number from 100 to 200 counts every 10 counts.
Thereafter, development processing and application of a gum solution were performed using an automatic developing machine 900N manufactured by Fuji Photo Film Co., Ltd. At that time, DN-6 (Fuji Photo Film Co., Ltd. developer) was used as the developer development replenisher, and FN-2 (Fuji Photo Film Co., Ltd. gum solution) was used as the gum solution.
The temperature of the first developer was 30 ° C., and the conveyance speed was adjusted so that the penetration time into the first developer was 12 seconds.
[0173]
5). Evaluation of planographic printing plates
The lithographic printing plate obtained above was evaluated for the presence or absence of a pot-like residual film, stain resistance and printing durability by the following methods. The respective results are shown in Table 3.
In addition, the following evaluation method was performed with three types of lithographic printing plates obtained by exposing and developing each lithographic printing plate precursor provided with the above three types of image recording layers I to III on each lithographic printing plate support. The evaluation in each example and comparative example showed the average value of these three types of lithographic printing plates.
[0174]
(1) Presence of pot-like residual film
The non-image part after development of the sample exposed with each plate surface energy amount or each count number was observed with an optical microscope at a magnification of 100 times, and the presence or absence of a pot in an area of 1 mm square was examined. The presence or absence of a pot-like residual film was evaluated based on the plate surface energy amount or the minimum count number of samples in which no spots were observed. The numerical values are expressed in 10 levels from 10 to 1, in order from the smaller plate surface energy amount or count.
It means that the larger the numerical value, the harder the formation of a pot-like residual film.
[0175]
(2) Dirt resistance
As for stain resistance, blanket stains were evaluated.
Using a Mitsubishi diamond type F2 printing machine (manufactured by Mitsubishi Heavy Industries, Ltd.), printing was performed using DIC-GEOS (s) red ink, and the blanket stain after printing 10,000 sheets was visually evaluated.
The numerical value was expressed in 10 levels from 10 to 1, in order from the least dirty blanket. The larger the number, the better the stain resistance.
[0176]
(3) Printing durability
Printing with Komori Corporation Lithron printing machine using DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc., when it is visually recognized that the density of the solid image has started to fade Printing durability was evaluated by the number of sheets.
The printing durability is the average of each Example and Comparative Example when the average number of printed lithographic printing plates in which the above three types of image recording layers are provided on the lithographic printing plate support of Comparative Example 1 is 100. The number of printed sheets was expressed as a relative value.
[0177]
[Table 4]

[0178]
[Table 5]

[0179]
As is apparent from Tables 2 and 3, a lithographic printing plate precursor using a low-purity aluminum plate and having an image recording layer provided on a lithographic printing plate support having a specific concavo-convex structure is a pot-like residual film. No occurrence of smudges and excellent stain resistance and printing durability (Examples 1 to 5).
In particular, a lithographic printing plate precursor provided with an image recording layer on a lithographic printing plate support using a low-purity aluminum plate having a tensile strength of 160 MPa or more can more effectively suppress the occurrence of a pot-like residual film. Moreover, it is excellent also in stain resistance and printing durability (Examples 1-4).
Further, when the average of the ratio of the depth to the opening diameter of the small wave structure is 0.2 or more, the printing durability is particularly improved.
[0180]
【The invention's effect】
As described above, a low-purity aluminum plate, preferably a high-wave structure with a specific wavelength and a medium-wave, small-wave structure with a specific opening diameter obtained by surface treatment or the like on a low-purity aluminum plate having a tensile strength in a specific range The use of the lithographic printing plate support of the present invention having a grained shape with a superposed structure on its surface can effectively suppress the occurrence of a pot-like residual film and cannot be removed from the conventional trade-off relationship. Both stain resistance and printing durability can be achieved.
[Brief description of the drawings]
FIG. 1 is a side view showing a concept of a brush graining process used in a mechanical surface roughening process in producing a lithographic printing plate support of the present invention.
FIG. 2 is a graph showing an example of an alternating waveform current waveform diagram used for electrochemical surface roughening treatment in producing a lithographic printing plate support of the present invention.
FIG. 3 is a side view showing an example of a radial type cell in an electrochemical surface roughening treatment using alternating current in producing a lithographic printing plate support of the present invention.
FIG. 4 is a schematic view of an anodizing apparatus used for anodizing treatment in the production of a lithographic printing plate support of the present invention.
[Explanation of symbols]
1 Aluminum plate
2, 4 Roller brush
3 Polishing slurry liquid
5, 6, 7, 8 Support rollers
11 Aluminum plate
12 Radial drum roller
13a, 13b main pole
14 Electrolytic treatment liquid
15 Electrolyte supply port
16 slits
17 Electrolyte passage
18 Auxiliary anode
19a, 19b Thyristor
20 AC power supply
40 Main electrolytic cell
50 Auxiliary anode tank
410 Anodizing equipment
412 Feed tank
414 Electrolytic treatment tank
416 Aluminum plate
418, 426 electrolyte
420 Power supply electrode
422, 428 rollers
424 Nip roller
430 Electrolytic electrode
432 tank wall
434 DC power supply

Claims (4)

A support for a lithographic printing plate obtained by subjecting an aluminum plate to a roughening treatment including a mechanical roughening treatment and an anodizing treatment,
The aluminum content of the aluminum plate is 95% by mass or more and less than 99.50% by mass,
Lithographic printing having a grain-like shape on the surface with a structure in which a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.20 μm are superimposed. Plate support. The lithographic printing plate support according to claim 1, wherein the aluminum plate has a tensile strength of 160 MPa or more. The lithographic printing plate support according to claim 1 or 2, wherein an average of a ratio of a depth to an opening diameter of the small wave structure is 0.2 or more. A lithographic printing plate precursor comprising an image recording layer provided on the lithographic printing plate support according to any one of claims 1 to 3.

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