JP2004004604A - Original plate for direct drawing waterlessl planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate for a direct drawing waterless planographic printing plate which enables a user to easily identify the types of the original plate changed in the kinds of silicone layers and the thicknesses of aluminum substrates even if these types coexist. <P>SOLUTION: The original plate for the direct drawing waterless planographic printing plate having at least a thermosensitive layer and ink repulsion layer on the substrate contains (a) a photothermal conversion substance and (b) dyes which are ≤0.01 g at room temperature 25°C in solubility in an aliphatic hydrocarbon solvent having an initial boiling point of ≥110°C and a dry point of ≤145°C and have an absorption peak in a visible light region. <P>COPYRIGHT: (C)2004,JPO

Description

（式中、ｎは２以上の整数を示し、Ｒ^１、Ｒ^２は炭素数１〜５０の置換あるいは非置換のアルキル基、炭素数２〜５０の置換あるいは非置換のアルケニル基、炭素数４〜５０の置換あるいは非置換のアリール基の群から選ばれる少なくとも１種の基を示し、それぞれ同一であっても異なっていてもよい。）
【００４０】
上記式中のＲ^１、Ｒ^２は全体の５０％以上がメチル基であることが、印刷版のインキ反発性の面で好ましい。また、分子量としては数千〜数十万のものが使用できるが、その取扱い性や得られた印刷版のインキ反発性、耐傷性などの観点から重量平均分子量１万〜２０万、さらには３万〜１５万のものを用いることが好ましい。
【００４１】
ＳｉＨ基含有ポリシロキサンとしては、分子鎖中、または末端にＳｉＨ基を有する、例えば下記一般式（ＩＩ）〜（Ｖ）で表されるような化合物を挙げることができる。
【００４２】
【化２】

（式中、ｎは１以上の整数である。）
【００４３】
【化３】

（式中、ｎは１以上の整数である。）
【００４４】
【化４】

（式中、ｎは１以上の整数、ｍは１以上の整数である。）
【００４５】
【化５】

【００４６】
ＳｉＨ基含有ポリシロキサン中におけるＳｉＨ基の量としては、１分子中２個以上、さらには３個以上であることが好ましい。ＳｉＨ基含有ポリシロキサンの添加量としては、シリコーンゴム層全組成物の３〜２０重量％であることが好ましく、５〜１５重量％がさらに好ましい。ポリジメチルシロキサンとの量比ということで言えば、ＳｉＨ基／ポリジメチルシロキサンのビニル基のモル比が１．５〜３０であることが好ましく、１０〜２０がさらに好ましい。このモル比が１．５以上であれば、シリコーンゴム層の硬化が不足することもなく、３０以下であればゴムの物性がもろくなり、印刷版の耐傷性などに悪影響を与えることがない。
【００４７】
反応抑制剤としては、含窒素化合物、リン系化合物、不飽和アルコールなどが挙げられるが、アセチレン基含有のアルコールなどが好ましく用いられる。反応抑制剤の好ましい添加量としては、シリコーンゴム組成物中の０．０１〜１０重量％、さらに好ましくは１〜５重量％である。
【００４８】
硬化触媒としては、ＩＩＩ族遷移金属化合物、好ましくは、白金化合物であり、具体的には白金単体、塩化白金、塩化白金酸、オレフィン配位白金、白金のアルコール変性錯体、白金のメチルビニルポリシロキサン錯体などを一例として挙げることができる。このような硬化触媒の量は、シリコーンゴム層中に固形分として０．０１〜２０重量％、好ましくは０．１〜１０重量％である。添加する触媒量が０．０１重量％以上の場合にはシリコーンゴム層の硬化が十分となり、さらに感熱層との接着性に問題を生じることもない。他方２０重量％以下の場合にはシリコーンゴム層溶液のポットライフに悪影響をもたらすこともない。シリコーンゴム層組成物中における白金などの金属の量で言えば、１０〜１０００ｐｐｍ、好ましくは１００〜５００ｐｐｍであることが好ましい。
【００４９】
また、これらの組成物の他に、縮合型シリコーンゴム層の組成物である水酸基含有オルガノポリシロキサンや加水分解性官能基含有シランもしくはシロキサン、ゴム強度を向上させる目的でシリカなどの公知の充填剤、接着性を向上させる目的で公知のシランカップリング剤、チタネート系カップリング剤、アルミニウム系カップリング剤などを含有してもよい。シランカップリング剤としては、アルコキシシラン類、アセトキシシラン類、ケトキシミンシラン類等が好ましく、特にビニル基を有するものや、ケトキシミンシラン類が好ましい。
【００５０】
また、縮合型のシリコーンゴム層を構成する成分としては、水酸基含有ポリジメチルシロキサン、架橋剤（脱酢酸型、脱オキシム型、脱アルコール型、脱アミン型、脱アセトン型、脱アミド型、脱アミノキシ型など）、および硬化触媒を含む。
【００５１】
水酸基含有ポリジメチルシロキサンも、上記一般式（Ｉ）で表される構造を有する。水酸基は分子末端および／もしくは主鎖中に位置することができるが、好ましく用いられるものは分子量末端に水酸基を有するものである。一般式中のＲ^１、Ｒ^２については、同様に全体の５０％以上がメチル基であることが、印刷版のインキ反発性の面で好ましい。分子量としては数千〜数十万のものが使用できるが、その取扱い性や得られた印刷版のインキ反発性、耐傷性などの観点から重量平均分子量１万〜２０万、さらには３万〜１５万のものを用いることが好ましい。
【００５２】
縮合型のシリコーンゴム層で用いられる架橋剤としては、下記一般式（ＶＩ）で表される、アセトキシシラン類、アルコキシシラン類、ケトキシミンシラン類、アリロキシシラン類などを挙げることができる。
（Ｒ^２）_４−ｎＳｉＸ_ｎ　　（ＶＩ）
（式中、ｎは２〜４の整数を示し、Ｒ^２は炭素数１以上の置換もしくは非置換のアルキル基、アルケニル基、アリール基、またはこれらの組み合わされた基を示す。Ｘはハロゲン原子、アルコキシ基、アシルオキシ基、ケトキシミン基、アミノオキシ基、アミド基、アルケニルオキシ基から選ばれる官能基を示す。）上記式において、加水分解性基の数ｎは３または４であることが好ましい。
【００５３】
具体的な化合物としては、メチルトリアセトキシシラン、エチルトリアセトキシシラン、ビニルトリアセトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、エチルトリメトキシシラン、エチルトリエトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、ビニルトリメトキシシラン、ビニルトリフェノキシシラン、ビニルトリエトキシシラン、アリルトリエトキシシラン、ビニルトリイソプロポキシシラン、ビニルトリスイソプロペノキシシラン、ビニルメチルビス（メチルエチルケトキシミン）シラン、メチルトリ（メチルエチルケトキシミン）シラン、ビニルトリ（メチルエチルケトキシミン）シラン、テトラ（メチルエチルケトキシミン）シラン、ジイソプロペノキシジメチルシラン、トリイソプロペノキシメチルシラン、テトラアリロキシシラン、などが挙げられるが、これらに限定されるものではない。これらの中では、シリコーンゴム層の硬化速度、取扱い性などの観点から、アセトキシシラン類、ケトキシミンシラン類が好ましい。
【００５４】
一般式（ＶＩ）で表される架橋剤の添加量としては、シリコーンゴム層全組成物の１．５〜２０重量％であることが好ましく、３〜１０重量％がさらに好ましい。ポリジメチルシロキサンとの量比ということで言えば、官能基Ｘ／ポリジメチルシロキサンの水酸基のモル比が１．５〜１０．０であることが好ましい。このモル比が１．５以上である場合には、シリコーンゴム層溶液のゲル化の心配もなく、逆に１０．０以下の場合にはゴムの物性の脆化、印刷版の耐傷性などへの悪影響も生じない。
【００５５】
硬化触媒としては、酢酸、プロピオン酸、マレイン酸などの有機カルボン酸、トルエンスルホン酸、ホウ酸等の酸類、水酸化カリウム、水酸化ナトリウム、水酸化リチウム等のアルカリ、アミン、およびチタンテトラプロポキシド、チタンテトラブトキシドなどの金属アルコキシド、鉄アセチルアセトナート、チタンアセチルアセトナートジプロポキシドなどの金属ジケテネート、金属の有機酸塩などを挙げることが出来る。これらの中では、金属の有機酸塩を添加することが好ましく、特に錫、鉛、亜鉛、鉄、コバルト、カルシウム、マンガンから選ばれる金属の有機酸塩であることが好ましい。このような化合物の具体例の一部としては、ジブチル錫ジアセテート、ジブチル錫ジオクテート、ジブチル錫ジラウレート、オクチル酸亜鉛、オクチル酸鉄などを挙げることが出来る。このような硬化触媒の量は、シリコーンゴム層中に固形分として０．０１〜２０重量％、好ましくは０．１〜１０重量％であることが好ましい。添加する触媒量が０．０１重量％以上とすればシリコーンゴム層の硬化が不十分となることはなく、さらに感熱層との接着性に問題を生じることもない。他方２０重量％以下とすればシリコーンゴム層溶液のポットライフに悪影響をもたらすこともない。
【００５６】
また、これらの組成物の他に、ゴム強度を向上させる目的でシリカなどの公知の充填剤、さらには公知のシランカップリング剤を含有してもよい。これらシリコーンゴム層の膜厚は０．５〜２０ｇ／ｍ^２が好ましく、１〜４ｇ／ｍ^２がさらに好ましい。膜厚が０．５ｇ／ｍ^２以上とすることにより印刷版のインキ反撥性や耐傷性、耐刷性が低下する傾向はなくなり、２０ｇ／ｍ^２以下とすれば経済的見地から有利であるばかりでなく、現像性、インキマイレージが悪くなるという問題がない。
【００５７】
本発明の直描型平版印刷版原版には、必要に応じてインキ反発層を保護する目的で保護フィルムをラミネートするかあるいは保護層を形成してもよい。保護フィルムとしてはポリエステルフィルム、ポリプロピレンフィルム、ポリビニルアルコールフィルム、エチレン酢酸ビニル共重合体ケン化物フィルム、ポリ塩化ビニリデンフィルムなどが挙げられる。このようにして得られた直描型水なし平版印刷版原版を、保護フィルムを剥離してから、あるいは保護フィルム上からレーザー光で画像状に露光する。
【００５８】
本発明の直描型水なし平版印刷版原版は、例えば次のようにして製造される。まず基板の上に、リバースロールコーター、エアナイフコーター、メーヤバーコーターなどの通常のコーター、あるいはホエラのような回転塗布装置を用い、感熱層組成物溶液を塗布、熱キュアし、感熱層を作製する。必要ならば、基板と感熱層の間に、同様な方法で断熱層を作製しても良い。この感熱層の上に、シリコーンゴム組成物溶液を、同様の方法で塗布、熱キュアし、シリコーンゴム層を作製する。そして最後に保護フィルムを設ける。
【００５９】
ここで、インキ反発層塗布溶液の溶剤としては炭化水素系溶剤が好ましく用いられ、単独、または数種を混合して用いることも可能である。炭化水素系溶剤としては公知の溶剤が用いられる。例えば脂肪族炭化水素溶剤（へキサン、ヘプタン、”アイソパーＥ、Ｈ、Ｇ”（エッソ化学（株）脂肪族炭化水素類の商標名）、ガソリン、灯油等）、芳香族炭化水素溶剤（ベンゼン、トルエン、キシレン等）、ハロゲン化炭化水素溶剤（トリクレン等）等が挙げられる。
【００６０】
本発明の直描型水なし平版印刷版原版から、レーザー照射の作用で感熱層表面に分解物を生じさせる工程、および、レーザー照射の作用で感熱層内部の硬化を進める工程により直描型平版印刷版を製造することができる。
【００６１】
製版露光工程で用いられるレーザー光源としては、発光波長領域が３００ｎｍ〜１５００ｎｍの範囲にあるものが用いられるが、これらの中でも近赤外領域付近に発光波長領域が存在する半導体レーザーやＹＡＧレーザーが好ましく用いられる。具体的には、明室での版材の取扱い性などの観点から、７８０ｎｍ、８３０ｎｍ、１０６４ｎｍの波長のレーザー光が製版に好ましく用いられる。
【００６２】
本発明においては、レーザー照射により感熱層表面に分解物を生じさせ、さらにレーザー照射により感熱層内部の硬化を進める。
【００６３】
レーザー照射後の製版方法は、少なくとも（１）レーザー照射部のシリコーンゴム層、感熱層間の接着力を低下させる「前処理工程」、および（２）レーザー照射部のシリコーンゴム層を剥離させる「現像工程」からなる。また、（３）画線部の感熱層を染色液で染色する「後処理工程」、および（４）処理液や染色液を完全に洗い落とす「水洗工程」を加えてもよい。
【００６４】
（１）前処理工程
前処理工程は、所定温度に保持した処理液中に、一定時間だけ版を浸漬させる工程である。レーザーを照射すると、その部位においてなんらかの変性（感熱層の分解物が生じたり、感熱層の耐溶剤性が変化するなど）を起こす。レーザーの照射エネルギーが大きければ、前処理工程を経ずに、そのまま現像工程に進んでも、レーザー照射部のシリコーンゴム層を剥離させることは可能である。しかし、照射エネルギーが小さい場合には、感熱層の変性が小さいため、現像工程のみでレーザー照射のＯＮ／ＯＦＦを感知することは難しく、現像不能となりやすい。この場合の印刷版のパターン形成に必要なエネルギーは大きなものとなり、版の感度は低くなってしまう。また、あまり大きなエネルギーのレーザーを照射すると、感熱層は破壊され、現像後には感熱層が残存しにくくなり、先に述べた印刷時の不利を被ることになる。そこで、レーザー照射のＯＮ／ＯＦＦの差を増幅し、低エネルギーの照射部の現像を行うためには、処理液で版を処理する工程が必要となる。前処理工程では、３０〜６０℃の温度の前処理液に１０〜１００秒浸漬させることが好ましい。３０℃未満の温度の前処理液に浸漬した場合、もしくは１０秒未満の時間浸漬した場合には、感熱層の膨潤あるいは溶解が十分でなく、シリコーンゴム層と感熱層間の接着力を十分に低下させることができない。また、６０℃を超えた温度の前処理液に浸漬した場合、もしくは１００秒を超える時間浸漬した場合には、感熱層が基板から剥離するなどの問題が生じる。
【００６５】
処理液中に版を浸漬させると、処理液はシリコーンゴム層中に浸透し、やがて感熱層まで到達する。照射部の感熱層はその上部において、熱分解物が生じていたり、あるいは処理液に対する溶解性が向上していたりするので、感熱層上部は処理液によって膨潤するかあるいは一部溶解してシリコーンゴム層、感熱層間の接着力が低下する。この状態で印刷版面を軽く擦ると、照射部のシリコーンゴム層は剥離し、下層の感熱層は露出してインキ着肉層となる。一方、未照射部の感熱層は処理液に対して不溶あるいは難溶なため、感熱層と強力に接着しているシリコーンゴム層は、強く擦っても剥がれない。このようにして、未照射部のシリコーンゴム層は現像されることなく、この部分がインキ反撥層となり、水なし平版印刷版の画像形成がなされる。
【００６６】
このような機構によって印刷版の高感度化が行われるため、処理液の選択は重要である。感熱層の溶解能が高い処理液を用いると、未照射部のシリコーンゴム層が剥離し、その度合いによっては感熱層までもが溶解されてしまい、その結果、前処理液などを汚染することによって、処理液の寿命を縮める。一方、感熱層の溶解能が低い処理液を用いると、照射部のシリコーンゴム層さえも現像する事ができず、印刷版の高感度化は果たされない。
【００６７】
このような前処理液としては、水にアルコールやケトン、エステル、カルボン酸、アミンなどの極性溶媒を添加したものや、脂肪族炭化水素類、芳香族炭化水素類などの少なくとも１種類からなる溶媒に極性溶媒を少なくとも１種類添加したもの、あるいは極性溶媒が用いられる。さらに、下記一般式（ＶＩＩ）で示されるグリコール化合物あるいはグリコールエーテル化合物を主成分として用いることが好ましい。
【００６８】
【化６】

（ここで、Ｒ^４は水素原子あるいは炭素数１〜５のアルキル基を示し、Ｒ^５およびＲ^６は水素原子あるいは炭素数１〜１５のアルキル基を示し、ｋは１〜１２の整数である。）
【００６９】
概して、グリコール化合物に比べると、グリコールエーテル化合物の方が感熱層に対する溶解能は高い。よって、両者の中で適当な化合物を選択するか、両者を混合することによって、感熱層の硬化具合の異なる版材に対して、最適な選択的溶解性を有する処理液を得ることができる。処理液としての効果は、感熱層の選択的溶解性だけでなく、シリコーンゴム層の膨潤能も加味される。シリコーンゴム層が膨潤すると、シリコーンゴムを剥がしやすくなるため、たとえ感熱層の溶解性が低い処理液でも現像しやすくなる。ただし、シリコーンが膨潤しすぎると現像時に擦り傷が付きやすくなるので、適当な範囲にとどめる必要がある。具体的には、シリコーンゴムの膨潤率が３０％以下のものが好ましく、さらに好ましくは１０％以下である。グリコール化合物によるシリコーンゴム層の膨潤率はほぼ０％であり、ほとんどシリコーンゴム層を膨潤させないので、単に感熱層の選択的溶解性のみが処理液としての適性に影響する。一方、エチレンオキサイドやプロピレンオキサイドなどの繰り返し単位が少なく、Ｒ^５やＲ^６にある程度長い直鎖の官能基を導入すると、シリコーンゴム層の膨潤能が高くなる。グリコールモノエーテルとグリコールジエーテルとでは、ジエーテルの方が、シリコーンゴムの膨潤能が一般的に高い。このような場合には、感熱層の選択的溶解性とシリコーンゴムの膨潤能の両者を考慮して処理液の設計を行う。
【００７０】
グリコール化合物として、エチレングリコール、プロピレングリコール、ブチレングリコール（１，２−ブタンジオール）、２，３−ブタンジオール、ｋ＝２〜１２のポリエチレングリコール、ポリプロピレングリコールが挙げられる。これらのグリコール化合物は単独あるいは２種以上混合して用いることができる。これらの中で、選択的溶解性の面から、ｋ＝２〜４であるジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、ジプロピレングリコール、トリプロピレングリコール、テトラプロピレングリコールが処理液として好ましく用いられる。
【００７１】
グリコールエーテル化合物として、上記グリコール化合物のモノアルキルエーテルおよびジアルキルエーテルが挙げられる。Ｒ^２やＲ^３のアルキル基として、メチル基、エチル基、プロピル基、ｉｓｏ−プロピル基、ブチル基、ｉｓｏ−ブチル基、ｔｅｒｔ−ブチル基、ヘプチル基、ヘキシル基、ヘプチル基、オクチル基、２−エチルヘキシル基、ノニル基、デカニル基、ウンデカニル基、ドデカニル基が挙げられる。好ましく用いられるグリコールエーテル化合物としては、ジエチレングリコールモノメチルエーテル（メチルカルビトール）、ジエチレングリコールモノエチルエーテル（エチルカルビトール）、ジエチレングリコールモノプロピルエーテル（プロピルカルビトール）、ジエチレングリコールモノブチルエーテル（ブチルカルビトール）、ジエチレングリコールモノヘキシルエーテル、ジエチレングリコールモノ２−エチルヘキシルエーテル、ジエチレングリコールジメチルエーテル（ジグライム）、ジエチレングリコールメチルエチルエーテル、ジエチレングリコールジエチルエーテル、トリエチレングリコールモノメチルエーテル、トリエチレングリコールモノエチルエーテル、トリエチレングリコールモノプロピルエーテル、トリエチレングリコールモノブチルエーテル、トリエチレングリコールモノヘキシルエーテル、トリエチレングリコールモノ２−エチルヘキシルエーテル、トリエチレングリコールジメチルエーテル（トリグライム）、トリエチレングリコールメチルエチルエーテル、トリエチレングリコールジエチルエーテル、テトラエチレングリコールモノメチルエーテル、テトラエチレングリコールモノエチルエーテル、テトラエチレングリコールモノプロピルエーテル、テトラエチレングリコールモノブチルエーテル、テトラエチレングリコールモノヘキシルエーテル、テトラエチレングリコール２−エチルヘキシルエーテル、テトラエチレングリコールジメチルエーテル（テトラグライム）、テトラエチレングリコールメチルエチルエーテル、テトラエチレングリコールジエチルエーテル、ジプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノエチルエーテル、ジプロピレングリコールモノプロピルエーテル、ジプロピレングリコールモノブチルエーテル、ジプロピレングリコールモノヘキシルエーテル、ジプロピレングリコールモノ２−エチルヘキシルエーテル、トリプロピレングリコールモノメチルエーテル、トリプロピレングリコールモノエチルエーテル、トリプロピレングリコールモノプロピルエーテル、トリプロピレングリコールモノブチルエーテル、トリプロピレングリコールモノヘキシルエーテル、トリプロピレングリコールモノ２−エチルヘキシルエーテル、テトラプロピレングリコールモノメチルエーテル、テトラプロピレングリコールモノエチルエーテル、テトラプロピレングリコールモノプロピルエーテル、テトラプロピレングリコールモノブチルエーテル、テトラプロピレングリコールモノヘキシルエーテル、テトラプロピレングリコールモノ２−エチルヘキシルエーテルが挙げられる。
【００７２】
上記一般式（１）で表されるグリコール化合物あるいはグリコールエーテル化合物の処理液中の含有量は、５０重量％〜１００重量％が好ましく、７０重量％〜９５重量％がより好ましい。５０重量％より少ないと感熱層の選択的溶解性に劣るため画像を再現することが困難になる。
【００７３】
また、本発明で使用する処理液には、アミン化合物を共存させることも好ましい。アミン化合物は選択的溶解性には劣るが、感熱層の溶解能が高いため、高感度化の目的で、処理液中に副成分として加えてもよい。
【００７４】
アミン化合物として、エチレングリコールアミン、ジエチレングリコールアミン、トリエチレングリコールアミン、テトラエチレングリコールアミン、プロピレングリコールアミン、ジプロピレングリコールアミン、トリプロピレングリコールアミンのようなグリコールアミン化合物や、メチルアミン、エチルアミン、ジメチルアミン、ジエチルアミン、トリメチルアミン、トリエチルアミン、プロピルアミン、ブチルアミン、アミルアミン、ジプロピルアミン、ジブチルアミン、ジアミルアミン、トリプロピルアミン、トリブチルアミン、メチルジエチルアミン、エチレンジアミン、トリメチレンジアミン、テトラメチレンジアミン、ポリエチレンイミン、ベンジルアミン、Ｎ，Ｎ−ジメチルベンジルアミン、Ｎ，Ｎ−ジエチルベンジルアミン、Ｎ，Ｎ−ジプロリルベンジルアミン、ｏ−、またはｍ−、ｐ−メトキシ、またはメチルベンジルアミン、Ｎ，Ｎ−ジ（メトキシベンジル）アミン、β−フェニルエチルアミン、γ−フェニルプロピルアミン、シクロヘキシルアミン、アニリン、モノメチルアニリン、ジメチルアニリン、トルイジン、αまたはβナフチルアミン、ｏ−、またはｍ−、またはｐ−フェニレンジアミン、アミノ安息香酸、２−（２−アミノエチル）エタノール、２−アミノ−２−メチル−１，３−プロパンジオール、２−アミノ−１，３−プロパンジオール、２−アミノ−２−ヒドロキシメチル−１，３−プロパンジオールなどが挙げられる。
【００７５】
アミン化合物の処理液中の含有量は、２５重量％以下が好ましく、１５重量％以下がより好ましい。２５重量％より多いと、感熱層に対する溶解力がかなり強くなるため、画線部のシリコーンゴム層のみでなく、非画線部まで剥離しやすくなるため、画像を再現することが困難になる。
【００７６】
また処理液中には、必要に応じて、水、アルコール類、カルボン酸類、エステル類、脂肪族炭化水素類（ヘキサン、へプランなど）、脂肪族炭化水素類（トルエン、キシレンなど）、ハロゲン化炭化水素類（トリクレンなど）を添加してもよい。また、現像時に版面を擦るときに、傷が入るのを防止するために、処理液中に硫酸塩、燐酸塩、カルボン酸塩、スルホン酸塩などの界面活性剤を加えてもよい。
【００７７】
（２）現像工程
前処理により、レーザー照射部では、感熱層表面が膨潤あるいは一部溶解しているため、選択的にシリコーンゴム層が剥がれやすくなっている。本発明では、水を用いて版面を擦ることにより現像を行う。処理液は親水性のグリコール化合物を主成分としているため、印刷版に浸透している処理液を水で洗い落とすことができるためである。水による現像は排液の点からも最も好ましい。温水や水蒸気を版面に噴射することによっても現像を行ってもよい。現像性を上げるために、水に処理液を加えたものを用いてもよい。現像液の温度は任意でよいが、１０℃〜５０℃が好ましい。
【００７８】
（３）後処理工程
現像により画線部が形成され、現像の確認を容易にするために染色液で染色する後処理工程を設けてもよい。本発明の染色液に用いられる染料としては、塩基性染料、酸性染料、直接染料、分散染料、および反応性染料などの中から単独で、あるいは２種以上のものを混合して用いることができる。なかでも、水溶性の塩基性染料および酸性染料が好ましく用いられる。
【００７９】
塩基性染料としては、”クリスタルバイオレット”、”エチルバイオレット”、”ビクトリアピュアブルー”、”ビクトリアブルー”、”メチルバイオレット”、”ＤＩＡＢＡＣＩＳ　ＭＡＧＥＮＴＡ”（三菱化学（株）製）、”ＡＩＺＥＮ　ＢＡＳＩＣ　ＣＹＡＮＩＮＥ　６ＧＨ”（保土ヶ谷化学工業（株）製）、”ＰＲＩＭＯＣＹＡＮＩＮＥ　ＢＸ　ＣＯＮＣ．”（住友化学（株）製）、”ＡＳＴＲＡＺＯＮ　ＢＬＵＥ　Ｇ”（ＦＡＲＢＥＮＦＡＲＲＩＫＥＮ　ＢＡＹＥＲ製）、”ＤＩＡＣＲＹＬ　ＳＵＰＲＡ　ＢＲＩＬＬＩＡＮＴ　２Ｂ”（三菱化学（株）製）、”ＡＩＺＥＮ　ＣＡＴＨＩＬＯＮ　ＴＵＲＱＵＯＩＳＥ　ＢＬＵＥ　ＬＨ”（保土ヶ谷化学工業（株）製）、”ＡＩＺＥＮ　ＤＩＡＭＯＮＤ　ＧＲＥＥＮ　ＧＨ”（保土ヶ谷化学工業（株）製）、”ＡＩＺＥＮ　ＭＡＬＡＣＨＩＴＥ　ＧＲＥＥＮ”（保土ヶ谷化学工業（株）製）などが用いられる。
【００８０】
酸性染料としては、”ＡＣＩＤ　ＶＩＯＲＥＴ　５Ｂ”（保土ヶ谷化学工業（株）製）、”ＫＩＴＯＮ　ＢＬＵＥ　Ａ”（ＣＩＢＡ製）、”ＰＡＴＥＮＴ　ＢＬＵＥ　ＡＦ”（ＢＡＳＦ製）、”ＲＡＫＵＴＯ　ＢＲＩＬＬＩＡＮＴ　ＢＬＵＥ　ＦＣＦ”（洛東化学工業（株）製）、”ＢＲＩＬＬＩＡＮＴ　ＡＣＩＤ　ＢＬＵＥ　Ｒ”（ＧＥＩＧＹ製）、”ＫＡＹＡＮＯＬ　ＣＹＡＮＩＮＥ　６Ｂ”（日本化薬（株）製）、”ＳＵＰＲＡＮＯＬ　ＣＹＡＮＩＮＥ　Ｇ”（ＦＡＲＢＥＮＦＡＲＲＩＫＥＮ　ＢＡＹＥＲ製）、”ＯＲＩＥＮＴ　ＳＯＬＵＢＬＥ　ＢＬＵＥ　ＯＢＢ”（オリエント化学工業（株）製）、”ＡＣＩＤ　ＢＲＩＬＬＩＡＮＴ　ＢＬＵＥ　５Ｇ”（中外化成（株）製）、”ＡＣＩＤ　ＢＲＩＬＬＩＡＮＴ　ＢＬＵＥ　ＦＦＲ”（中外化成（株）製）、”ＡＣＩＤ　ＧＲＥＥＮ　ＧＢＨ”（高岡化学工業（株）製）、”ＡＣＩＤ　ＢＲＩＬＬＩＡＮＴ　ＭＩＬＬＩＮＧ　ＧＲＥＥＮ　Ｂ”（保土ヶ谷化学工業（株）製）などが用いられる。
【００８１】
これら染料の染色液中の含有量は、０．０１重量％〜１０重量％が好ましく、０．１重量％〜５重量％がより好ましい。
【００８２】
本発明に用いられる染色液の溶媒としては、水、アルコール類、グリコール類、グリコールモノアルキルエーテル類、グリコールジアルキルエーテル類が用いられ、これらの溶媒は単独あるいは２種以上混合して用いられる。グリコール類、グリコールモノアルキルエーテル類、グリコールジアルキルエーテル類は処理液としての効果を有するので、仮に現像工程でレーザー照射部のシリコーンゴム層が現像できず付着していても、後処理工程で現像させることもできる。
【００８３】
その他、染色助剤、有機酸、無機酸、消泡剤、可塑剤、界面活性剤を任意に添加してもよい。
【００８４】
染色液の温度は任意でよいが、１０℃〜５０℃が好ましい。また、現像液中に上記染料を添加しておいて、現像と同時に画像部の染色化を行うこともできる。
【００８５】
（４）水洗工程
版面に処理液が浸透したままになっていると、経時により非画線部のシリコーンゴム層が剥離しやすくなる場合があるため、処理液や染色液を版面から完全に洗い落とす水洗工程を設けてもよい。水洗水の温度は任意でよいが、１０℃〜５０℃が好ましい。
【００８６】
これまで述べてきた工程による現像方法としては、手による現像でも自動現像装置による現像のどちらでも良い。手による現像では、これらの処理液および現像液を順次不織布、脱脂綿、布、スポンジなどに含浸させて版面を拭き取ることによって行うことが出来る。自動現像装置を用いる場合には、前処理部、現像部および後処理部がこの順に設けられているものが好ましい。場合によっては後処理部の後方にさらに水洗部が設けられていてもよい。このような自動現像機としては東レ（株）製のＴＷＬ−１１６０、ＴＷＬ−６５０、あるいは特開平４−２２６５号公報や特開平５−２２７２号公報、特開平５−６０００号公報などに開示されている現像装置が挙げられる。
【００８７】
【実施例】
以下、本発明を実施例によりさらに詳しく説明する。
【００８８】
実施例１
厚さ０．２４ｍｍの脱脂したアルミ板上に下記の組成よりなる溶液をスリットダイコーターにより塗布し、１３０℃×３０秒間乾燥し、１ｇ／ｍ^２の感熱層を設けた。
【００８９】
＜感熱層溶液＞
（ａ）近赤外線吸収染料“ＰＲＯＪＥＴ”８２５ＬＤＩ（（株）Ａｖｅｃｉａ製）　：１１重量部
（ｂ）可視領域に吸収を持つ染料“ＯＩＬ　ＳＣＡＲＬＥＴ３０８”（オリエント化学工業（株）製）（”アイソパーＥ、”（エッソ化学（株）対する溶解度０．００５）２部
（ｃ）チタンジ−ｎ−ブトキサイドビス（２，４−ペンタンジオネート）“ナーセムチタン”（日本化学産業（株）製）：２２重量部
（ｄ）フェノールノボラック樹脂“スミライトレジン”ＰＲ５４６５２（住友デュレズ（株）製）：６０重量部
（ｅ）ポリウレタン“サンプレン”ＬＱＴ１３３１Ｄ（三洋化成（株）製）：１０重量部
（ｆ）ｍ−キシリレンジアミン／グリシジルメタクリレート／３−グリシドキシプロピルトリメトキシシラン＝１／３／１ｍｏｌ比付加反応物：１５重量部
（ｇ）テトラヒドロフラン：８００重量部
（ｈ）ジメチルホルムアミド：１００重量部
次いで、下記シリコーン溶液を乾燥膜厚２．０μｍ、乾燥条件は１２０℃×１２０秒としてスリットダイコーターにより塗布し、シリコーンゴム層を設けた。
【００９０】
＜シリコーンゴム層＞
（ａ）α，ω−ジビニルポリジメチルシロキサン（分子量約６０，０００）：１００重量部
（ｂ）ＨＭＳ−５０１（チッソ（株）製　両末端メチル（メチルハイドロジェンシロキサン）（ジメチルシロキサン）共重合体　ＳｉＨ基数／分子量＝０．６９ｍｏｌ／ｇ）：７重量部
（ｃ）“ＢＹ２４−８０８”（東レダウコーニングシリコーン（株）製、反応抑制剤）：３重量部
（ｄ）“ＳＲＸ−２１２”（東レダウコーニングシリコーン（株）製、白金触媒）：５重量部
（ｅ）ビニルトリ（メチルエチルケトオキシム）シラン：３重量部
（ｆ）“アイソパー”Ｅ（エッソ化学（株）製）：１０００重量部
上記のようにして得られた積層板にカバーフィルムとして厚さ８μｍのポリプロピレンフィルム“トレファン”ＢＯ（東レ（株）製）をカレンダーローラーを用いてラミネートし、直描型水なし平版印刷版原版を得た。
【００９１】
この後、この印刷版原版を”ＦＸ４００−ＡＰ”（製版機、東レエンジニアリング（株）製）に装着し、半導体レーザー（波長８３０ｎｍ、ビーム直径２０μｍ）を用いて露光時間１０μｓで照射エネルギー１５０ｍＪ／ｃｍ^２で露光を行った。　続いて、自動現像機”ＴＷＬ−８６０ＫＩＩ”（東レ（株）製、前処理液：ＮＰ−１（東レ（株）製）、現像液：水、後処理液：ＮＡ−１（東レ（株）製））により、前処理時間３０秒という条件で、上記露光済み版の現像を行い、直描型水なし平版印刷版を得た。ここで、剥離後のカバーフィルムを目視により観察した結果、染料による着色は見られなかった。
【００９２】
＜＜画像再現性の評価＞＞
得られた印刷版を枚葉オフセット印刷機”スプリント２５”（小森コーポレーション（株）製）に取り付け、水なし平版用インキ“ドライオカラーＮＳＩ”、藍（大日本インキ化学工業（株）製）を使用して上質紙（６２．５ｋｇ／菊）に印刷し、印刷物としての画像再現性を評価したところ１〜９９％の網点を再現し、良好な画像再現性が得られた。
【００９３】
＜＜印刷版のＵＶスペクトルの測定＞＞
“Ｓｐｅｃｔｒｏｐｈｏｔｏｍｅｔｅｒ　Ｕ−３２１０”（日立製作所（株）製）を用いてＵＶ吸収スペクトルを測定した。その結果、約５２０ｎｍに吸収ピークを有し、染料を添加していないもの（比較例１）との吸光度差は０．３５であった。
【００９４】
＜＜検版性の評価＞＞
印刷に供した印刷版を印刷機から取り外し、インキがついた状態で印刷版を２５倍のルーペで観察することにより、検版性を評価した。その結果、１％の網点まで容易に確認することができ、検版性が良好であることがわかった。
【００９５】
実施例２〜５
実施例１における感熱層組成の（ｂ）“ＯＩＬ　ＳＣＡＲＬＥＴ３０８”を表２に示す染料に変更した以外は全く同様にして平版印刷版を作製した。実施例１と同様の評価を行ったところ、カバーフィルムへの着色もなく、画像再現性、検版性ともに良好であった。また、それぞれ可視光領域４５０〜６００ｎｍに吸収ピークを有し、染料を添加していないもの（比較例３）との吸光度差は０．１以上であった。
【００９６】
実施例６
実施例１において感熱層中の成分（ａ）を“ＹＫＲ−２９００”（山本化成（株）製）に変更した以外は全く同様にして印刷版原版を作製し、直描型平版印刷版を得た。実施例１と同様に評価したところ、カバーフィルムへの着色もなく、画像再現性、検版性ともに良好であった。また、ＵＶ吸収スペクトルを測定した結果、５１５ｎｍに吸収ピークを有し染料を添加していないもの（比較例４）との吸光度差は０．３０であった。
【００９７】
実施例７
実施例１において感熱層中の成分（ａ）を“ＫＡＹＡＳＯＲＢ”ＰＳ１０１（日本化薬（株）製）に変更した以外は全く同様にして印刷版原版を作製し、直描型平版印刷版を得た。実施例１と同様に評価したところ、カバーフィルムへの着色もなく、画像再現性も良好であった。また、印刷板を観察した結果、４％の網点まで確認することができた。ＵＶ吸収スペクトルを測定した結果、５１５ｎｍに吸収ピークを有し染料を添加していないもの（比較例５）との吸光度差は０．２９であった。
【００９８】
実施例８
厚さ０．２４ｍｍの脱脂したアルミ板上に下記の組成よりなる溶液をスリットダイコーターにより塗布し、１９０℃×６０秒間乾燥し、６．０ｇ／ｍ^２の断熱層を設けた。
【００９９】
（酸化チタン分散液の作製方法）
ジメチルホルムアミド１０重量部中に、酸化チタン”ＣＲ−５０”（石原産業（株）製）１０重量部を添加して５分間撹拌した。更に、ガラスビーズ（Ｎｏ．０８）を１５重量部添加し、２０分間激しく撹拌し、ガラスビーズを取り去ることで酸化チタン分散液を得た。この酸化チタン分散液を用いて、さらに以下の溶液を調合した。
【０１００】
＜断熱層溶液１＞
（ａ）エポキシ樹脂”エピコート”１０１０（油化シェルエポキシ（株）製）：３５重量部
（ｂ）ポリウレタン“サンプレン”ＬＱ−Ｔ１３３１Ｄ（三洋化成（株）製）：４０重量部
（ｃ）金属キレート“アルミキレート”ＡＬＣＨ−ＴＲ（川研ファインケミカル（株）製）：８重量部
（ｄ）ビニル系重合物“ディスパロン”ＬＣ９５１（楠本化成（株）製）：０．１重量部
（ｅ）酸化チタン分散液：７２重量部
（ｆ）ジメチルホルムアミド：９００重量部。
【０１０１】
次いで下記の組成よりなる感熱層溶液をスリットダイコーターにより塗布し、１３０℃×３０秒間乾燥して１．５ｇ／ｍ^２の感熱層を設けた。
【０１０２】
＜感熱層溶液＞
（ａ）近赤外線吸収染料“ＰＲＯＪＥＴ”８２５ＬＤＩ（（株）Ａｖｅｃｉａ製）　：１１重量部
（ｂ）可視領域に吸収を持つ染料“Ｒｈｏｄａｍｉｎｅ６ＧＣＰ”（田岡化学工業（株）製）”アイソパーＥ、”（エッソ化学（株）対する溶解度０ｇ）：２部
（ｃ）チタンジ−ｎ−ブトキサイドビス（２，４−ペンタンジオネート）“ナーセムチタン”（日本化学産業（株）製）：２２重量部
（ｄ）フェノールノボラック樹脂“スミライトレジン”ＰＲ５４６５２（住友デュレズ（株）製）：６０重量部
（ｅ）ポリウレタン“サンプレン”ＬＱＴ１３３１Ｄ（三洋化成（株）製）：１０重量部
（ｆ）ｍ−キシリレンジアミン／グリシジルメタクリレート／３−グリシドキシプロピルトリメトキシシラン＝１／３／１ｍｏｌ比付加反応物：１５重量部
（ｇ）テトラヒドロフラン：８００重量部
（ｈ）ジメチルホルムアミド：１００重量部。
【０１０３】
次いで、下記シリコーン溶液を乾燥膜厚２．０μｍ、乾燥条件を１２０℃×１２０秒としてスリットダイコーターにより塗布し、シリコーンゴム層を設けた。
【０１０４】
＜シリコーンゴム層＞
（ａ）α，ω−ジビニルポリジメチルシロキサン（分子量約６０，０００）：１００重量部
（ｂ）ＨＭＳ−５０１（チッソ（株）製　両末端メチル（メチルハイドロジェンシロキサン）（ジメチルシロキサン）共重合体　ＳｉＨ基数／分子量＝０．６９ｍｏｌ／ｇ）：７重量部
（ｃ）“ＢＹ２４−８０８”（東レダウコーニングシリコーン（株）製、反応抑制剤）：３重量部
（ｄ）“ＳＲＸ−２１２”（東レダウコーニングシリコーン（株）製、白金触媒）：５重量部
（ｅ）ビニルトリ（メチルエチルケトオキシム）シラン：３重量部
（ｆ）“アイソパー”Ｅ（エッソ化学（株）製）：１０００重量部。
【０１０５】
実施例１と同様の評価を行ったところ、カバーフィルムへの着色もなく、画像再現性、検版性ともに良好であった。また、それぞれ可視光領域４５０〜６００ｎｍに吸収ピークを有し、染料を添加していないもの（比較例３）との吸光度差は０．５以上であった。
【０１０６】
比較例１
実施例１における感熱層組成の（ｂ）を“ＯＩＬ　ＲＥＤ　ＲＲ”に変更した以外は全く同様にして平版印刷版を作製した。実施例１と同様の評価を行ったところ、印刷物では１〜９９％の網点を再現し検版性も良好であった。しかし、カバーフィルムを確認した結果、着色していることを確認した。
【０１０７】
比較例２
実施例１における感熱層組成の（ｂ）を“ＯＩＬ　ＲＥＤ　５Ｂ”に変更した以外は全く同様にして平版印刷版を作製した。実施例１と同様の評価を行ったところ、印刷物では１〜９９％の網点を再現し検版性も良好であった。しかし、カバーフィルムを確認した結果、着色していることを確認した。
【０１０８】
比較例３
実施例１における感熱層組成から（ｂ）“ＯＩＬ　ＳＣＡＲＬＥＴ３０８”（オリエント化学工業（株）製）を抜いた以外は全く同様にして平版印刷版を作製した。実施例１と同様に評価したところ、印刷物では１〜９９％の網点を再現し良好な画像再現性が得られた。また、印刷板を観察した結果、１％の網点まで容易に確認でき、検版性も良好であった。ここで可視光領域４５０〜６００ｎｍに吸収ピークは存在せず、ベースラインの値は０．０５であった。
【０１０９】
比較例４
実施例６における感熱層組成から（ｂ）“ＯＩＬ　ＳＣＡＲＬＥＴ３０８”（オリエント化学工業（株）製）を抜いた以外は全く同様にして平版印刷版を作製した。実施例１と同様に評価したところ、印刷物では１〜９９％の網点を再現し良好な画像再現性が得られた。また、印刷板を観察した結果、１％の網点まで容易に確認でき、検版性も良好であった。ここで可視光領域４５０〜６００ｎｍに吸収ピークは存在せず、ベースラインの値は０．１であった。
【０１１０】
比較例５
実施例７における感熱層組成から（ｂ）“ＯＩＬ　ＳＣＡＲＬＥＴ３０８”（オリエント化学工業（株）製）を抜いた以外は全く同様にして平版印刷版を作製した。実施例１と同様に評価したところ、印刷物では１〜９９％の網点を再現し良好な画像再現性が得られた。また、印刷板を観察した結果、４％の網点まで確認することができた。ここで可視光領域４５０〜６００ｎｍに吸収ピークは存在せず、ベースラインの値は０．１であった。
【０１１１】
【表１】

【０１１２】
【表２】

【０１１３】
【表３】

【０１１４】
【発明の効果】本発明によれば、直描型水なし平版印刷版原版において、優れた版性能有し、かつ様々な外観の直描型水なし平版印刷版原版が得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a direct-drawing lithographic printing plate precursor that can be directly made by laser light, and particularly to a direct-drawing lithographic printing plate precursor that can be printed without using dampening water.
[0002]
[Prior art]
So-called direct-printing plate making, which does not use plate-making films and produces offset printing plates directly from manuscripts, is simple, does not require skill, is quick to obtain printing plates in a short period of time, and offers quality from a variety of systems. Taking advantage of such features as rationality that can be selected according to cost and cost, the company has begun to enter the field of general offset printing and flexographic printing as well as the light printing industry. Particularly recently, new types of various direct-drawing lithographic printing plate precursors have been developed due to rapid advances in output systems such as prepress systems, imagesetters, and laser printers. These direct-drawing lithographic printing plate precursors can be classified according to the plate-making method, such as a method of irradiating a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode, and an ink repellent layer or ink coating with an inkjet. Examples include a method of forming a layer. Above all, the method using laser light is superior to other methods in terms of resolution and plate making speed, and there are many types thereof.
[0003]
The printing plate precursors using the laser light are further classified into two types, a photon mode by a photoreaction and a heat mode by performing a photothermal conversion to cause a thermal reaction. In particular, the heat mode method has an advantage that it can be handled in a bright room, and its usefulness has recently been reviewed due to the rapid progress of a semiconductor laser as a light source.
[0004]
For example, Patent Literature 1, Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 8, Patent Literature 9, Patent Literature 10, Patent Literature 11, Patent Literature 12, Patent Literature 13, Patent Literature 14, Patent Literature 15, Patent Literature 16, and Patent Literature 17 describe a direct-drawing waterless planographic printing plate precursor using a laser beam as a light source, a plate making method thereof, and the like.
[0005]
The heat-sensitive layer of the printing plate precursor of this thermal destruction method mainly uses carbon black as a laser light absorbing compound and nitrocellulose as a thermal decomposition compound. The carbon black is converted into thermal energy by absorbing the laser light, and the heat destroys the heat-sensitive layer. Finally, by removing this portion by development, the silicone rubber layer on the surface is simultaneously peeled off to form an ink-coated portion.
[0006]
However, this printing plate has a problem in that since the image is formed by destroying the heat-sensitive layer, the depth of the cells in the image area becomes deep, the ink deposition property at minute halftone dots is poor, and the ink mileage is poor. there were. Further, there is also a problem that a crosslinked structure is formed in order to easily cause the heat-sensitive layer to be thermally destroyed, and that the printing durability of the printing plate precursor is poor. Further, this printing plate precursor has a problem that the sensitivity is low and a high laser light intensity is required to destroy the heat-sensitive layer.
[0007]
In Patent Document 18, a layer in which adhesion to a silicone rubber layer is reduced by converting laser light into heat, and an addition-type silicone rubber layer containing 10 to 20% by weight of an organohydrogensiloxane based on the solid content are described. And a heat-free lithographic printing plate precursor having a heat mode. However, in the same publication, the heat-sensitive layer is basically composed of carbon black and nitrocellulose, is of a type that is removed by laser irradiation and development, and the ink-receiving layer is a primer layer below the heat-sensitive layer. Therefore, there is a problem of ink mileage and a problem of intensity of laser light required for plate making. Patent Literature 19 enables high sensitivity by including hollow polymer fine particles in a primer layer. However, the problem of ink mileage still remained.
[0008]
Patent Document 20 describes a release development type printing plate containing a substance that generates an acid in a laser-sensitive layer and a polymer compound that is decomposed by the action of an acid. Therefore, there are problems inherent in peeling development such that the steps are complicated and the reproducibility of fine halftone dots is poor.
[0009]
In addition, Patent Literature 21, Patent Literature 22, and Patent Literature 23 describe a direct drawing type waterless planographic printing plate precursor using a metal thin film as a heat-sensitive layer. This printing plate material has a very thin heat-sensitive layer, so that a very sharp image can be obtained, which is advantageous in terms of the resolution of the printing plate. There has been a problem that the heat-sensitive layer at the line portion is peeled off, ink adheres, and becomes a defect on printed matter.
[0010]
In order to solve the above-mentioned problems, in Patent Documents 24, 25, and 26, the silicone rubber layer in a portion irradiated with a laser beam is selectively removed, while the heat-sensitive layer remains thermally separated. A direct drawing type waterless planographic printing plate precursor has been proposed.
[0011]
As the waterless lithographic printing plate precursor, a type in which the type and film thickness of the silicone rubber layer are changed for each application such as high definition and printing durability is on the market. However, since the silicone rubber layer is transparent and has the same appearance, there is a problem that if these are mixed, it is difficult for the user to identify them. In addition, there is a similar problem with the thickness of the aluminum substrate, and a prescription for facilitating identification of the type of plate has been strongly desired.
[0012]
[Patent Document 1]
U.S. Pat. No. 5,339,737
[Patent Document 2]
U.S. Pat. No. 5,353,705
[Patent Document 3]
JP-A-6-55723
[Patent Document 4]
U.S. Pat. No. 5,378,580
[Patent Document 5]
JP-A-7-164773
[Patent Document 6]
JP-A-6-186750
[Patent Document 7]
JP-A-7-309001
[Patent Document 8]
JP-A-9-104182
[Patent Document 9]
JP-A-9-146264
[Patent Document 10]
JP-A-9-146265
[Patent Document 11]
JP-A-9-236927
[Patent Document 12]
JP-A-9-244228
[Patent Document 13]
U.S. Pat. No. 5,487,338
[Patent Document 14]
U.S. Pat. No. 5,385,092
[Patent Document 15]
U.S. Pat. No. 5,649,486
[Patent Document 16]
U.S. Pat. No. 5,704,291
[Patent Document 17]
U.S. Pat. No. 5,570,636
[Patent Document 18]
JP-A-9-239943
[Patent Document 19]
JP-A-9-244228
[Patent Document 20]
JP-A-9-239942
[Patent Document 21]
U.S. Pat. No. 5,379,698
[Patent Document 22]
JP-A-7-314934
[Patent Document 23]
JP-A-9-236927
[Patent Document 24]
JP-A-11-221977
[Patent Document 25]
JP-A-11-227353
[Patent Document 26]
JP-A-11-35267
[0013]
[Problems to be solved by the invention]
An object of the present invention is to provide a prescription of a heat-peelable, direct-drawing, waterless lithographic printing plate precursor capable of changing only the appearance without deteriorating the plate performance in order to improve the disadvantages of the prior art.
[0014]
[Means for Solving the Problems]
The direct drawing type lithographic printing plate precursor according to the invention mainly has the following constitution in order to solve the above-mentioned problems. That is, "a direct drawing type waterless lithographic printing plate precursor having at least a heat-sensitive layer and an ink repellent layer on a substrate, wherein (a) a light-to-heat conversion material, and (b) an initial boiling point of 110 And a dye having an absorption peak in the visible light region at a room temperature of 25 ° C. of 0.01 g or less, and a solubility in an aliphatic hydrocarbon solvent having a dry point of 145 ° C. or lower. A direct drawing type waterless planographic printing plate precursor.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
A feature of the present invention is a direct-drawing waterless lithographic printing plate precursor having at least a heat-sensitive layer and an ink repellent layer on a substrate, wherein (a) a light-to-heat conversion material, A dye having a solubility in an aliphatic hydrocarbon solvent having a point of 110 ° C. or more and a dry point of 145 ° C. or less, 0.01 g or less at room temperature 25 ° C. and having an absorption peak in a visible light region. It is.
[0016]
First, (b) the solubility in an aliphatic hydrocarbon solvent having an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less is 0.01 g or less at room temperature 25 ° C. and has an absorption peak in a visible light region. The dye will be described.
[0017]
In the present invention, the absorption peak of the dye is a value measured in an actual printing plate in consideration of a case where the peak wavelength shifts due to interaction with other components in the heat-sensitive layer. As a method for measuring the UV absorption spectrum, a reflection method and a transmission method are mentioned. When the substrate of the printing plate uses a UV non-transmissive substrate such as aluminum, the reflection method is used, and the substrate is made of polyethylene terephthalate or the like. When a UV-transmissive substrate is used, it is preferable to measure by a transmission method. The visible region refers to a wavelength range in the electromagnetic spectrum that is perceived by human eyes as light, and indicates a range of about 400 to 700 nm. In the present invention, a dye having an absorption peak at 450 to 600 nm is particularly preferably used. The addition of the dye to the heat-sensitive layer enhances the absorption in the visible region and causes a difference in appearance, so that it is easy to distinguish the heat-sensitive layer from the dye without the dye. Here, if the difference in absorbance is 0.1 or more, and more preferably 0.2 or more, the identification is not possible as compared with the case where no dye is added or the case where no dye is added. It becomes possible.
[0018]
The dye (b) in the present invention not only has an absorption peak in the visible light region, but also has an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less at room temperature (25 ° C.). Must be 0.01 g or less. This is because some dyes bleed to the surface of the ink repellent layer and stained the hands during handling, and when a cover film was provided on the ink repellent layer, the cover film was colored. As a result, the above problem is caused by the solubility of the dye in the coating solution for the ink repellent layer. In other words, dyes that are easily dissolved in the aliphatic hydrocarbon solvent used in the ink repellent layer coating solution are easy to bleed to the surface of the ink repellent layer. Conversely, by using a dye having low solubility in these hydrocarbon solvents. Bleed can be prevented.
[0019]
As a result of further detailed examination, the dye having an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less in an aliphatic hydrocarbon solvent having a solubility of 0.01 g or less at a room temperature of 25 ° C. It was found that bleeding on the surface of the ink repellent layer could be substantially prevented. The solubility refers to the concentration of a solute in a saturated solution, and in the case of a solid, is represented by the amount of a solute per 100 g of a solvent (gram number) or the amount of a solute per 100 g of solution (gram number). In addition, the solubility changes depending on the temperature at the time of dissolution.
[0020]
As used herein, the aliphatic hydrocarbon solvents include hexane, heptane, etc., as well as “Isoper E”, “Isoper H” and “Isoper G” (all are trademarks of aliphatic hydrocarbon solvents of Esso Chemical Co., Ltd.). Solvent), gasoline, kerosene and the like. Specific examples of the aliphatic hydrocarbon solvent having an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less include “Isoper E” (trade name of an aliphatic hydrocarbon solvent of Esso Chemical Co., Ltd.). Can be
[0021]
From the above, it is necessary that the dye used in the present invention has a solubility in an aliphatic hydrocarbon solvent having an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less at room temperature of 25 ° C. of 0.01 g or less. And a dye insoluble in the above solvent can be particularly preferably used. The solubility in the same aliphatic hydrocarbon solvent as the solvent actually used for the ink repellent layer coating solution is preferably 0.01 g or less. Dyes having a solubility in an aliphatic hydrocarbon solvent of 0.01 g or less are not extracted from the heat-sensitive layer into the coating solution for the ink repellent layer and are not taken into the ink repellent layer, so that they do not bleed to the surface of the ink repellent layer. That is, by using the dye, only the appearance can be changed without lowering the plate performance.
[0022]
(B) The solubility in an aliphatic hydrocarbon solvent having an initial boiling point of 110 ° C. or more and a dry point of 145 ° C. or less at room temperature 25 ° C. of 0.01 g or less at room temperature of 25 ° C., and an absorption peak in a visible light region. Any known dye can be used as long as these conditions are satisfied. Specific examples include monoazo dyes, polyazo dyes, metal salt azo dyes, stilbene azo dyes, pyrazolone azo dyes, thiazole azo dyes, anthraquinone dyes, anthrone dyes, indigo dyes, thioindigo dyes, phthalocyanine dyes, naphthalocyanine dyes, Diphenylmethane dye, triphenylmethane dye, xanthene dye, acridine dye, azine dye, oxazine dye, thiazine dye, polymethine dye, azomethine dye, quinoline dye, nitro dye, nitroso dye, benzoquinone dye, naphthoquinone dye, naphthalimide dye, verinone dye And the like, but the present invention is not limited to these.
[0023]
The proportion of the dye (b) in the heat-sensitive layer is preferably from 0.1% by weight to 20% by weight of the total solids of the heat-sensitive layer, more preferably from 0.5% to 10% by weight. When the amount is 0.1% by weight or more, a sufficient effect is obtained. When the amount is 20% by weight or less, characteristics such as developability and image reproducibility are not affected.
[0024]
As the light-to-heat converting substance (a) used in the heat-sensitive layer of the present invention, known light-to-heat converting substances can be mentioned. Specific examples include phthalocyanine, naphthalocyanine-based green pigment, diamine-based metal complex, dithiol-based metal complex, phenolthiol-based metal complex, mercaptophenol-based metal complex, water-containing inorganic compound, copper sulfate, chromium sulfide, and silicate Examples thereof include compounds, metal oxides such as titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, and tungsten oxide, and hydroxides and sulfates of these metals. Dyes that absorb infrared rays or near infrared rays, particularly dyes, are preferably used as the light-to-heat conversion material. Particularly preferred dyes are cyanine-based, phthalocyanine-based, naphthalocyanine-based, dithiol metal complex-based, piasurenium-based, squarylium-based, croconium-based, azo-based disperse dyes, bisazo-based, bisazostilbene-based, naphthoquinone-based, anthraquinone-based, Examples include perylene, polymethine, indoaniline metal complex dyes, intermolecular CT, benzothiopyran, spiropyran, nigrosine, thioindigo, nitroso, quinoline, and fulgide dyes, particularly dyes.
[0025]
The content of the photothermal conversion material (a) is preferably 1 to 40% by weight, more preferably 5 to 25% by weight of the total solids of the heat-sensitive layer. When the content is 1% by weight or more, the effect of improving the sensitivity to laser light is large, and when the content is 40% by weight or less, the printing durability of the printing plate does not decrease.
[0026]
Particularly, in the present invention, a light-to-heat conversion material is preferably used which is added to the heat-sensitive layer and whose absorbance characteristics of the heat-sensitive layer are as follows in a UV absorption spectrum measured by a reflection method.
(1) a main peak of the absorption spectrum exists between 700 and 1200 nm;
(2) The absorbance at 830 nm (A) and the absorbance at 650 nm (B)
Ratio: (A / B) is 1.5 or more
By using such a light-to-heat conversion substance, a large contrast difference between the image area and the non-image area can be obtained, so that a direct-drawing waterless planographic printing plate precursor having extremely good plate inspection properties can be obtained.
[0027]
Specific examples of preferred commercially available light-to-heat conversion materials include the following products of the “KAYASORB” series CY-10, CY-17, CY-5, CY-4, CY-2, IRG-002 (Nippon Kayaku Co., Ltd.) YKR-4010, YKR-3030, YKR-3070, SIR-159, PA-1005, SIR-128, YKR-2080, PA-1006 (Yamamoto Kasei Co., Ltd.), "PROJET" 825LDI, "PROJET""830NP, S1749963, S174270 (manufactured by Avecia Limited), NK-2014, NK-2911, NK-2912, NK-4432, NK-4474, NK-4489, NK-4680, NK-4776, NK-5020, NK- 5036, NK-5042, (Hayashibara Institute of Biological Sciences) ), IR2T, IR3T (Showa Denko KK), "EXCOLOR" 801K, IR-1, IR-2, "TX-EX-801B", "TX-EX-805K" (manufactured by Nippon Shokubai Co., Ltd.) ), CIR-1080 (manufactured by Nippon Carlit Co., Ltd.), IR98011, IR980301, IR980401, IR980402, IR980405, IR980406, IR980504 (manufactured by YAMADA CHEMICAL Co., Ltd.), "EPOLIGHT" V-149, V-129, V- 63, III-184, III-192, IV-62B, IV-67, VI-19, VI-148 (manufactured by EPOLIN, Inc.), but are not limited thereto.
[0028]
The thermosensitive layer of the present invention preferably contains a thermosetting compound. The thermosetting compound in the present invention refers to a group of compounds in the heat-sensitive layer of the printing plate precursor, which still have the ability to be cured directly or indirectly by the action of laser irradiation. Novolak resin and resol resin, phenol / furfural resin, furan resin, unsaturated polyester, alkyd resin, urea resin, melamine resin obtained by the condensation reaction of phenols such as phenol, cresol and xylenol with formaldehyde , A guanamine resin, an epoxy resin, a diallyl phthalate resin, an unsaturated polyurethane resin, a polyimide precursor, and the like, but are not limited thereto.
[0029]
Further, in addition to the resin itself reacting as described above, a composition obtained by adding a thermoreactive cross-linking agent to a compound having a reactive functional group can also be used in the present invention as a thermosetting compound. . Examples of the cross-linking agent include known polyfunctional compounds having a cross-linking property, such as polyfunctional blocked isocyanate, polyfunctional epoxy compound, polyfunctional acrylate compound, metal chelate compound, polyfunctional aldehyde, polyfunctional mercapto compound, and polyfunctional alkoxy. Examples thereof include a silyl compound, a polyfunctional amine compound, a polyfunctional carboxylic acid, a polyfunctional vinyl compound, a polyfunctional diazonium salt, a polyfunctional azide compound, and hydrazine. Further, a known catalyst may be added to promote the reaction of the crosslinking agent. These crosslinking agents can be used alone or in combination of two or more.
[0030]
Further, a compound that generates an acid or an amine under the action of heat and a compound that cures under the action of the generated acid or amine can also be used in the present invention. Among such thermosetting compounds, a combination of a phenol resin and a metal chelate compound is particularly preferred.
[0031]
The proportion of such a thermosetting compound in the thermosensitive layer is preferably 10 to 95% by weight, more preferably 30 to 70% by weight of the total solids of the thermosensitive layer. When the amount of the thermosetting compound is 10% by weight or more, the effect of improving the solvent resistance of the image portion heat-sensitive layer due to the heat curing of the heat-sensitive layer is observed. There is no problem in image formability by laser irradiation due to the reduced amount of thermally decomposable compounds and photothermal conversion substances.
[0032]
In addition, the heat-sensitive layer may contain a binder polymer, a surfactant, and various additives. Specific examples of the binder polymer include acrylates such as polymethyl methacrylate and polybutyl methacrylate, homopolymers and copolymers of methacrylates, polystyrene, α-methylstyrene, and homopolymers of styrene monomers such as hydroxystyrene. Homopolymers and copolymers of copolymers and copolymers, various synthetic rubbers such as isoprene and styrene-butadiene, vinyl esters such as polyvinyl acetate and vinyl chloride, and polyoxides (polyethers such as polyethylene oxide and polypropylene oxide) ), Polyesters, polyurethanes, polyamides, cellulose derivatives such as ethylcellulose, cellulose acetate, phenoxy resin, methylpentene resin, polyparaxylylene resin, polyphenylene Such as Fido resin and the like.
[0033]
The content of these binders is preferably from 5 to 70% by weight, more preferably from 10 to 50% by weight, based on the total solids of the heat-sensitive layer. When the content is 5% by weight or more, there is no problem in printing durability and coating properties of the coating solution, and when the content is 70% by weight or less, there is no adverse effect on image reproducibility. The thickness of the heat-sensitive layer is 0.1 to 10 g / m as a coating layer. ² Is preferable in terms of the printing durability of the printing plate and the point that the dilution solvent is easily volatilized and the productivity is excellent, and 1 to 5 g / m ² Is more preferred.
[0034]
It is effective to provide a heat insulating layer in the direct drawing type lithographic printing plate precursor according to the invention in order to prevent heat from the irradiated laser from escaping to the substrate. A known primer layer which has been conventionally used for strengthening the adhesiveness between the substrate and the ink receiving layer may be used as a substitute.
[0035]
When using a heat insulating layer in the present invention, it is preferable to satisfy the following conditions. That is, an effect is obtained in that the aluminum substrate and the ink receiving layer are well bonded, are stable over time, and have high resistance to a developing solution and a solvent used for printing. Those satisfying such conditions include those containing epoxy resin, polyurethane resin, phenol resin, acrylic resin, alkyd resin, polyester resin, polyamide resin, urea resin, polyvinyl butyral resin, casein, gelatin and the like. Among these, it is preferable to use a polyurethane resin, a polyester resin, an acrylic resin, an epoxy resin, a urea resin, or the like alone or as a mixture of two or more. It is also preferable to add additives such as pigments and dyes to the heat insulating layer to improve plate inspection. The thickness of the heat insulating layer is 0.5 to 50 g / m in the form of a coating layer. ² Is preferably 1 to 10 g / m ² Is more preferred. 0.5g / m thickness ² By doing so, the effect of blocking morphological defects and chemical adverse effects on the substrate surface is improved, and 50 g / m ² The following is advantageous from an economic point of view.
[0036]
Examples of the ink repellent layer used in the present invention include a hydrophilic layer made of vinyl alcohols and the like, a hydrophilic layer containing acrylic acid and acrylate, sulfonic acid and sulfonic acid salt, and JP-A-8-282142. It is possible to use a hydrophilic swelling layer, a silicone rubber layer, a layer containing a fluorine compound, and the like proposed in Japanese Unexamined Patent Publication Nos. Hei 8-282144, Hei 8-292558, Hei 9-54425, and the like. However, it is preferably a silicone rubber layer. As the silicone rubber layer, any of an addition reaction type and a condensation reaction type can be used.
[0037]
Components constituting the addition type silicone rubber layer include vinyl group-containing polydimethylsiloxane, SiH group-containing polysiloxane, and a reaction inhibitor for the purpose of controlling the curing rate, and a curing catalyst.
[0038]
The vinyl group-containing polydimethylsiloxane has a structure represented by the following general formula (I), and has a vinyl group at a molecular terminal and / or in a main chain.
[0039]
Embedded image

(Wherein, n represents an integer of 2 or more; ¹ , R ² Is at least one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, and a substituted or unsubstituted aryl group having 4 to 50 carbon atoms. And the groups may be the same or different. )
[0040]
R in the above formula ¹ , R ² It is preferable that 50% or more of the polymer is a methyl group in terms of ink repellency of the printing plate. Further, the molecular weight may be in the range of thousands to hundreds of thousands, but from the viewpoints of handleability, ink repellency and scratch resistance of the obtained printing plate, the weight-average molecular weight is 10,000 to 200,000, and more preferably 3 to 100,000. It is preferable to use a material of 10,000 to 150,000.
[0041]
Examples of the SiH group-containing polysiloxane include compounds having a SiH group in a molecular chain or at a terminal and represented by, for example, the following general formulas (II) to (V).
[0042]
Embedded image

(In the formula, n is an integer of 1 or more.)
[0043]
Embedded image

(In the formula, n is an integer of 1 or more.)
[0044]
Embedded image

(In the formula, n is an integer of 1 or more, and m is an integer of 1 or more.)
[0045]
Embedded image

[0046]
The amount of SiH groups in the SiH group-containing polysiloxane is preferably 2 or more, more preferably 3 or more in one molecule. The addition amount of the SiH group-containing polysiloxane is preferably from 3 to 20% by weight, more preferably from 5 to 15% by weight, based on the total composition of the silicone rubber layer. Speaking of the quantitative ratio with polydimethylsiloxane, the molar ratio of SiH group / vinyl group of polydimethylsiloxane is preferably 1.5 to 30, and more preferably 10 to 20. When the molar ratio is 1.5 or more, the curing of the silicone rubber layer does not become insufficient, and when the molar ratio is 30 or less, the physical properties of the rubber become brittle and the scratch resistance of the printing plate is not adversely affected.
[0047]
Examples of the reaction inhibitor include a nitrogen-containing compound, a phosphorus-based compound, and an unsaturated alcohol, and an acetylene group-containing alcohol is preferably used. The preferable addition amount of the reaction inhibitor is 0.01 to 10% by weight, more preferably 1 to 5% by weight in the silicone rubber composition.
[0048]
As the curing catalyst, a Group III transition metal compound, preferably a platinum compound, specifically, platinum alone, platinum chloride, chloroplatinic acid, olefin-coordinated platinum, an alcohol-modified complex of platinum, and methylvinylpolysiloxane of platinum A complex or the like can be given as an example. The amount of such a curing catalyst is 0.01 to 20% by weight, preferably 0.1 to 10% by weight as a solid content in the silicone rubber layer. When the amount of the catalyst to be added is 0.01% by weight or more, the silicone rubber layer is sufficiently cured, and there is no problem in adhesion to the heat-sensitive layer. On the other hand, when the content is 20% by weight or less, there is no adverse effect on the pot life of the silicone rubber layer solution. In terms of the amount of metal such as platinum in the silicone rubber layer composition, it is preferably 10 to 1000 ppm, and more preferably 100 to 500 ppm.
[0049]
In addition to these compositions, a known filler such as a hydroxyl group-containing organopolysiloxane or a hydrolyzable functional group-containing silane or siloxane, which is a composition of the condensation type silicone rubber layer, and silica for the purpose of improving rubber strength. For the purpose of improving adhesiveness, a known silane coupling agent, titanate coupling agent, aluminum coupling agent and the like may be contained. As the silane coupling agent, alkoxysilanes, acetoxysilanes, ketoximine silanes and the like are preferable, and those having a vinyl group and ketoximine silanes are particularly preferable.
[0050]
The components constituting the condensation type silicone rubber layer include a hydroxyl group-containing polydimethylsiloxane, a crosslinking agent (deacetic acid type, deoxime type, dealcohol type, deamine type, deacetone type, deamide type, deamidoxy type). And a curing catalyst.
[0051]
The hydroxyl group-containing polydimethylsiloxane also has a structure represented by the general formula (I). The hydroxyl group can be located at the molecular terminal and / or in the main chain, but those preferably used are those having a hydroxyl group at the molecular weight terminal. R in the general formula ¹ , R ² It is similarly preferable that 50% or more of the whole is a methyl group from the viewpoint of the ink repellency of the printing plate. As the molecular weight, those having a molecular weight of several thousand to several hundred thousand can be used, but from the viewpoints of handleability, ink repellency and scratch resistance of the obtained printing plate, the weight average molecular weight is 10,000 to 200,000, and further 30,000 to It is preferable to use 150,000.
[0052]
Examples of the crosslinking agent used in the condensation type silicone rubber layer include acetoxysilanes, alkoxysilanes, ketoximinesilanes, and allyloxysilanes represented by the following general formula (VI).
(R ² ) _4-n Six _n (VI)
(Wherein, n represents an integer of 2 to 4; ² Represents a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 or more carbon atoms, or a combination thereof. X represents a functional group selected from a halogen atom, an alkoxy group, an acyloxy group, a ketoximine group, an aminooxy group, an amide group, and an alkenyloxy group. In the above formula, the number n of the hydrolyzable groups is preferably 3 or 4.
[0053]
Specific compounds include methyltriacetoxysilane, ethyltriacetoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, tetraethoxysilane, tetrapropoxysilane, Vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltriethoxysilane, allyltriethoxysilane, vinyltriisopropoxysilane, vinyltrisisopropenoxysilane, vinylmethylbis (methylethylketoximine) silane, methyltri (methylethylketoximine) silane , Vinyltri (methylethylketoximine) silane, tetra (methylethylketoximine) silane, diisopropenoxydimethylsilane, triisoprope Carboxymethyl silane, tetra allyloxy silane, but like, but it is not limited thereto. Among these, acetoxy silanes and ketoximine silanes are preferred from the viewpoints of the curing speed of the silicone rubber layer, handleability, and the like.
[0054]
The amount of the crosslinking agent represented by the general formula (VI) is preferably from 1.5 to 20% by weight, more preferably from 3 to 10% by weight, based on the total composition of the silicone rubber layer. Speaking of the quantitative ratio with polydimethylsiloxane, the molar ratio of the functional group X / hydroxyl group of polydimethylsiloxane is preferably 1.5 to 10.0. When the molar ratio is 1.5 or more, there is no risk of gelation of the silicone rubber layer solution, and when the molar ratio is 10.0 or less, the physical properties of the rubber become brittle and the printing plate becomes scratch-resistant. There is no adverse effect.
[0055]
Examples of the curing catalyst include organic carboxylic acids such as acetic acid, propionic acid and maleic acid, acids such as toluenesulfonic acid and boric acid, alkalis such as potassium hydroxide, sodium hydroxide and lithium hydroxide, amines, and titanium tetrapropoxide. Metal alkoxides such as titanium tetrabutoxide, metal diketenates such as iron acetylacetonate and titanium acetylacetonate dipropoxide, and organic acid salts of metals. Among these, it is preferable to add a metal organic acid salt, particularly preferably a metal organic acid salt selected from tin, lead, zinc, iron, cobalt, calcium and manganese. Specific examples of such compounds include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. The amount of such a curing catalyst is preferably 0.01 to 20% by weight, preferably 0.1 to 10% by weight as a solid content in the silicone rubber layer. When the amount of the catalyst to be added is 0.01% by weight or more, the curing of the silicone rubber layer does not become insufficient, and there is no problem in the adhesiveness to the heat-sensitive layer. On the other hand, if the content is 20% by weight or less, the pot life of the silicone rubber layer solution is not adversely affected.
[0056]
Further, in addition to these compositions, a known filler such as silica and a known silane coupling agent may be contained for the purpose of improving rubber strength. The thickness of these silicone rubber layers is 0.5 to 20 g / m ² Is preferred, and 1 to 4 g / m ² Is more preferred. 0.5 g / m film thickness ² By doing so, the ink repellency, scratch resistance and printing durability of the printing plate do not tend to be reduced, and are reduced to 20 g / m2. ² The following is not only advantageous from an economic point of view, but also has no problem that the developability and the ink mileage are deteriorated.
[0057]
A protective film may be laminated or a protective layer may be formed on the direct-lithographic printing plate precursor according to the invention for the purpose of protecting the ink repellent layer, if necessary. Examples of the protective film include a polyester film, a polypropylene film, a polyvinyl alcohol film, a saponified ethylene-vinyl acetate copolymer film, and a polyvinylidene chloride film. The thus obtained direct drawing type waterless planographic printing plate precursor is exposed imagewise with a laser beam after the protective film is peeled off or from above the protective film.
[0058]
The direct-drawing waterless planographic printing plate precursor of the invention is manufactured, for example, as follows. First, a heat-sensitive layer composition solution is applied and heat-cured on a substrate using a normal coater such as a reverse roll coater, an air knife coater, or a Mayer bar coater, or a spin coater such as a wooler to prepare a heat-sensitive layer. . If necessary, a heat insulating layer may be formed between the substrate and the heat-sensitive layer in a similar manner. On this heat-sensitive layer, a silicone rubber composition solution is applied and heat-cured in the same manner to prepare a silicone rubber layer. Finally, a protective film is provided.
[0059]
Here, as the solvent for the ink repellent layer coating solution, a hydrocarbon solvent is preferably used, and it is also possible to use a single solvent or a mixture of several solvents. Known solvents are used as the hydrocarbon-based solvent. For example, aliphatic hydrocarbon solvents (hexane, heptane, "Isoper E, H, G" (trade names of aliphatic hydrocarbons of Esso Chemical Co., Ltd.), gasoline, kerosene, etc.), aromatic hydrocarbon solvents (benzene, Toluene, xylene, etc.) and halogenated hydrocarbon solvents (trichlene, etc.).
[0060]
From the direct-drawing waterless lithographic printing plate precursor of the present invention, a step of generating a decomposition product on the surface of the heat-sensitive layer by the action of laser irradiation, and a step of promoting the curing of the inside of the heat-sensitive layer by the action of laser irradiation. Printing plates can be manufactured.
[0061]
As the laser light source used in the plate-making exposure step, those having an emission wavelength region in the range of 300 nm to 1500 nm are used. Among these, a semiconductor laser or a YAG laser having an emission wavelength region near the near infrared region is preferable. Used. Specifically, a laser beam having a wavelength of 780 nm, 830 nm, or 1064 nm is preferably used for plate making from the viewpoint of handleability of the plate material in a bright room.
[0062]
In the present invention, a decomposition product is generated on the surface of the heat-sensitive layer by laser irradiation, and the inside of the heat-sensitive layer is further cured by laser irradiation.
[0063]
The plate making method after laser irradiation includes at least (1) a “pretreatment step” for reducing the adhesive force between the silicone rubber layer and the heat-sensitive layer in the laser irradiation section, and (2) “development” for peeling off the silicone rubber layer in the laser irradiation section. Process ". In addition, (3) a “post-treatment step” for dyeing the heat-sensitive layer in the image area with a staining liquid, and (4) a “water-washing step” for completely washing off the treatment liquid and the staining liquid may be added.
[0064]
(1) Pretreatment process
The pretreatment step is a step in which the plate is immersed in a treatment liquid maintained at a predetermined temperature for a certain time. Irradiation with the laser causes some modification (such as generation of decomposition products of the heat-sensitive layer or change in the solvent resistance of the heat-sensitive layer) at the site. If the irradiation energy of the laser is large, it is possible to peel off the silicone rubber layer of the laser-irradiated portion without going through the pre-treatment step and proceeding to the development step as it is. However, when the irradiation energy is small, it is difficult to detect ON / OFF of the laser irradiation only in the developing step because the heat-sensitive layer is less denatured, so that the development tends to be impossible. In this case, the energy required for forming the pattern of the printing plate becomes large, and the sensitivity of the plate becomes low. In addition, when a laser beam having too large energy is irradiated, the heat-sensitive layer is destroyed, and the heat-sensitive layer hardly remains after development, and suffers from the above-described disadvantage during printing. Therefore, in order to amplify the difference between ON / OFF of laser irradiation and to develop the low-energy irradiated portion, a process of processing the plate with a processing liquid is required. In the pretreatment step, it is preferable to immerse the pretreatment liquid at a temperature of 30 to 60 ° C for 10 to 100 seconds. When immersed in a pretreatment liquid at a temperature of less than 30 ° C. or for less than 10 seconds, the swelling or dissolution of the thermosensitive layer is not sufficient, and the adhesive strength between the silicone rubber layer and the thermosensitive layer is sufficiently reduced. I can't let it. Further, when immersed in a pretreatment liquid at a temperature exceeding 60 ° C. or when immersed for more than 100 seconds, a problem such as peeling of the heat-sensitive layer from the substrate occurs.
[0065]
When the plate is immersed in the processing liquid, the processing liquid penetrates into the silicone rubber layer and eventually reaches the heat-sensitive layer. The upper part of the heat-sensitive layer of the irradiation part has a thermal decomposition product generated in the upper part or the solubility in the processing liquid is improved. The adhesive strength between the layers and the heat-sensitive layer decreases. When the printing plate surface is lightly rubbed in this state, the silicone rubber layer at the irradiated portion is peeled off, and the lower heat-sensitive layer is exposed to become an ink-coated layer. On the other hand, since the heat-sensitive layer in the non-irradiated portion is insoluble or hardly soluble in the treatment liquid, the silicone rubber layer strongly bonded to the heat-sensitive layer does not peel off even if strongly rubbed. In this manner, the unirradiated portion of the silicone rubber layer is not developed, and this portion becomes an ink repellent layer, and an image of a waterless planographic printing plate is formed.
[0066]
Since the sensitivity of the printing plate is increased by such a mechanism, the selection of the processing liquid is important. When a processing liquid having a high heat-sensitive layer dissolving power is used, the silicone rubber layer in the unirradiated portion is peeled off, and depending on the degree, even the heat-sensitive layer is dissolved, and as a result, the pretreatment liquid is contaminated. And shorten the life of the processing solution. On the other hand, when a processing solution having a low solubility of the heat-sensitive layer is used, even the silicone rubber layer in the irradiated area cannot be developed, and the sensitivity of the printing plate cannot be increased.
[0067]
Examples of such a pretreatment liquid include a solvent obtained by adding a polar solvent such as alcohol, ketone, ester, carboxylic acid, and amine to water, and a solvent composed of at least one kind of aliphatic hydrocarbons and aromatic hydrocarbons. To which at least one polar solvent is added, or a polar solvent is used. Further, it is preferable to use a glycol compound or a glycol ether compound represented by the following general formula (VII) as a main component.
[0068]
Embedded image

(Where R ⁴ Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; ⁵ And R ⁶ Represents a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and k is an integer of 1 to 12. )
[0069]
In general, glycol ether compounds have higher solubility in the thermosensitive layer than glycol compounds. Therefore, by selecting an appropriate compound or mixing the two, it is possible to obtain a processing solution having an optimum selective solubility for plate materials having different curing conditions of the heat-sensitive layer. The effect of the treatment liquid is determined not only by the selective solubility of the heat-sensitive layer, but also by the swelling ability of the silicone rubber layer. When the silicone rubber layer swells, the silicone rubber is easily peeled off, so that even a processing solution having a low solubility of the heat-sensitive layer is easily developed. However, if the silicone is excessively swelled, abrasion is likely to occur during development, so it is necessary to keep the silicone within an appropriate range. Specifically, the swelling ratio of the silicone rubber is preferably 30% or less, more preferably 10% or less. The swelling rate of the silicone rubber layer by the glycol compound is almost 0%, and almost no swelling of the silicone rubber layer. Therefore, only the selective solubility of the heat-sensitive layer affects the suitability as a treatment liquid. On the other hand, there are few repeating units such as ethylene oxide and propylene oxide, and R ⁵ And R ⁶ Introducing a somewhat long linear functional group into the silicone rubber increases the swelling ability of the silicone rubber layer. Of glycol monoether and glycol diether, diether generally has higher swelling ability of silicone rubber. In such a case, the treatment liquid is designed in consideration of both the selective solubility of the heat-sensitive layer and the swelling ability of the silicone rubber.
[0070]
Examples of the glycol compound include ethylene glycol, propylene glycol, butylene glycol (1,2-butanediol), 2,3-butanediol, polyethylene glycol with k = 2 to 12, and polypropylene glycol. These glycol compounds can be used alone or in combination of two or more. Among these, from the viewpoint of selective solubility, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol in which k is 2 to 4 are preferably used as the treatment liquid.
[0071]
Examples of the glycol ether compound include a monoalkyl ether and a dialkyl ether of the above glycol compound. R ² And R ³ As the alkyl group of methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, tert-butyl, heptyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl Group, decanyl group, undecanyl group and dodecanyl group. Preferred glycol ether compounds include diethylene glycol monomethyl ether (methyl carbitol), diethylene glycol monoethyl ether (ethyl carbitol), diethylene glycol monopropyl ether (propyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), and diethylene glycol monohexyl. Ether, diethylene glycol mono 2-ethylhexyl ether, diethylene glycol dimethyl ether (diglyme), diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethyl Glycol monobutyl ether, triethylene glycol monohexyl ether, triethylene glycol mono 2-ethylhexyl ether, triethylene glycol dimethyl ether (triglyme), triethylene glycol methyl ethyl ether, triethylene glycol diethyl ether, tetraethylene glycol monomethyl ether, tetraethylene Glycol monoethyl ether, tetraethylene glycol monopropyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol monohexyl ether, tetraethylene glycol 2-ethylhexyl ether, tetraethylene glycol dimethyl ether (tetraglyme), tetraethylene glycol methyl ethyl ether, tetraethylene Glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monohexyl ether, dipropylene glycol mono 2-ethylhexyl ether, tripropylene glycol monomethyl Ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, tripropylene glycol monohexyl ether, tripropylene glycol mono 2-ethylhexyl ether, tetrapropylene glycol monomethyl ether, tetrapropylene glycol monoethyl ether , Tetrapropylene glycol monopropyl ether, tetrapropylene glycol monobutyl ether, tetrapropylene glycol monohexyl ether, and tetrapropylene glycol mono-2-ethylhexyl ether.
[0072]
The content of the glycol compound or glycol ether compound represented by the general formula (1) in the treatment liquid is preferably 50% by weight to 100% by weight, and more preferably 70% by weight to 95% by weight. When the amount is less than 50% by weight, it is difficult to reproduce an image because of poor selective solubility of the heat-sensitive layer.
[0073]
It is also preferable that an amine compound coexist in the treatment liquid used in the present invention. The amine compound is poor in selective solubility, but has a high solubility in the heat-sensitive layer, and may be added as an auxiliary component to the processing solution for the purpose of increasing sensitivity.
[0074]
As the amine compound, ethylene glycol amine, diethylene glycol amine, triethylene glycol amine, tetraethylene glycol amine, propylene glycol amine, dipropylene glycol amine, glycolamine compounds such as tripropylene glycol amine, methylamine, ethylamine, dimethylamine, Diethylamine, trimethylamine, triethylamine, propylamine, butylamine, amylamine, dipropylamine, dibutylamine, diamylamine, tripropylamine, tributylamine, methyldiethylamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, polyethyleneimine, benzylamine, N, N-dimethylbenzylamine, N, N-diethylbenzyla , N, N-diprolylbenzylamine, o- or m-, p-methoxy, or methylbenzylamine, N, N-di (methoxybenzyl) amine, β-phenylethylamine, γ-phenylpropylamine, cyclohexylamine Aniline, monomethylaniline, dimethylaniline, toluidine, α or β naphthylamine, o- or m-, or p-phenylenediamine, aminobenzoic acid, 2- (2-aminoethyl) ethanol, 2-amino-2-methyl -1,3-propanediol, 2-amino-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol and the like.
[0075]
The content of the amine compound in the treatment liquid is preferably 25% by weight or less, more preferably 15% by weight or less. If the content is more than 25% by weight, the dissolving power for the heat-sensitive layer is considerably increased, so that not only the silicone rubber layer in the image area but also the non-image area is easily peeled off, making it difficult to reproduce an image.
[0076]
In the treatment liquid, if necessary, water, alcohols, carboxylic acids, esters, aliphatic hydrocarbons (hexane, heplan, etc.), aliphatic hydrocarbons (toluene, xylene, etc.), halogenated Hydrocarbons (such as trichlene) may be added. Further, a surfactant such as a sulfate, a phosphate, a carboxylate, or a sulfonate may be added to the processing solution in order to prevent scratches when the plate surface is rubbed during development.
[0077]
(2) Development process
Due to the pretreatment, the surface of the heat-sensitive layer swells or partially dissolves in the laser-irradiated portion, so that the silicone rubber layer is selectively easily peeled off. In the present invention, development is performed by rubbing the plate surface with water. This is because the treatment liquid contains a hydrophilic glycol compound as a main component, so that the treatment liquid permeating the printing plate can be washed off with water. Development with water is most preferred from the viewpoint of drainage. Development may also be performed by injecting hot water or steam onto the plate surface. To increase developability, a mixture of water and a processing solution may be used. The temperature of the developer may be arbitrarily set, but is preferably from 10C to 50C.
[0078]
(3) Post-processing step
An image portion may be formed by development, and a post-processing step of dyeing with a dye solution may be provided to facilitate confirmation of development. As the dye used in the dyeing solution of the present invention, a basic dye, an acid dye, a direct dye, a disperse dye, a reactive dye, or the like can be used alone, or a mixture of two or more dyes can be used. . Among them, water-soluble basic dyes and acid dyes are preferably used.
[0079]
Examples of basic dyes include “crystal violet”, “ethyl violet”, “victoria pure blue”, “victoria blue”, “methyl violet”, “DIABACIS MAGENTA” (manufactured by Mitsubishi Chemical Corporation), and “AIZEN BASIC Cyanine 6GH”. (Manufactured by Hodogaya Chemical Industry Co., Ltd.), "PRIMOCYANINE BX CONC." (Manufactured by Sumitomo Chemical Co., Ltd.), "ASTRAZON BLUE G" (manufactured by FARBENFARRIKEN BAYER), "DIACRYL SUPRA BRILLIANT 2B" (manufactured by Mitsubishi Chemical) ), "AIZEN CATHILON TURQUAOISE BLUE LH" (manufactured by Hodogaya Chemical Industry Co., Ltd.), "AIZEN DIAMOND GREEN GH" (manufactured by Hodogaya Chemical Industry Co., Ltd.), "A IZEN MALACHITE GREEN "(manufactured by Hodogaya Chemical Industry Co., Ltd.) or the like is used.
[0080]
Examples of the acidic dye include “ACID VIORET 5B” (manufactured by Hodogaya Chemical Industry Co., Ltd.), “KITON BLUE A” (manufactured by CIBA), “PATENT BLUE AF” (manufactured by BASF), and “RAKUTO BRILLIANT BLUE FCF” (Rakuto Chemical) Industrial Co., Ltd.), "BRILLIANT ACID BLUE R" (manufactured by GEIGY), "KAYANOL Cyanine 6B" (manufactured by Nippon Kayaku Co., Ltd.), "SUPRANOL Cyanine G" (manufactured by FARBENFARIKEN BAYER), "ORIBENBLUEBLUEBLUEBLUEBLUEBLUEBLUEBLUEBLUEBLUEBLUEBLUELANCEL BABYER (Orient Chemical Industry Co., Ltd.), "ACID BRILLIANT BLUE 5G" (Chugai Kasei Co., Ltd.), "ACID BRILLIANT BLUE FFR" (Chugai Kasei Co., Ltd.), "ACID" REEN GBH "(manufactured by Takaoka Chemical Co. (Ltd.))," ACID BRILLIANT MILLING GREEN B "(Hodogaya Chemical Co., Ltd.) and the like can be used.
[0081]
The content of these dyes in the dyeing solution is preferably from 0.01% by weight to 10% by weight, more preferably from 0.1% by weight to 5% by weight.
[0082]
Water, alcohols, glycols, glycol monoalkyl ethers and glycol dialkyl ethers are used as the solvent of the dyeing solution used in the present invention, and these solvents are used alone or in combination of two or more. Since glycols, glycol monoalkyl ethers, and glycol dialkyl ethers have an effect as a processing liquid, even if the silicone rubber layer of the laser irradiation part cannot be developed in the developing step and adheres, it is developed in the post-processing step. You can also.
[0083]
In addition, a coloring aid, an organic acid, an inorganic acid, an antifoaming agent, a plasticizer, and a surfactant may be optionally added.
[0084]
The temperature of the dyeing solution may be arbitrary, but is preferably from 10 ° C to 50 ° C. The dye may be added to the developer so that the image area is dyed simultaneously with the development.
[0085]
(4) Washing process
If the processing liquid is still infiltrated into the plate surface, the silicone rubber layer in the non-image area may be easily peeled off with the passage of time.Therefore, a water washing step for completely removing the processing liquid and the dyeing liquid from the plate surface is provided. Is also good. The temperature of the washing water may be arbitrary, but is preferably from 10 ° C to 50 ° C.
[0086]
As the developing method according to the steps described above, either manual development or development using an automatic developing apparatus may be used. Manual development can be performed by sequentially impregnating a nonwoven fabric, absorbent cotton, cloth, sponge, or the like with these processing solutions and developing solutions and wiping the plate surface. When an automatic developing device is used, it is preferable that a pre-processing section, a developing section, and a post-processing section are provided in this order. In some cases, a water washing section may be further provided behind the post-processing section. Examples of such an automatic developing machine are disclosed in TWL-1160 and TWL-650 manufactured by Toray Industries, Inc., JP-A-4-2265, JP-A-5-2272, and JP-A-5-6000. Developing device.
[0087]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0088]
Example 1
A solution having the following composition was applied on a degreased aluminum plate having a thickness of 0.24 mm using a slit die coater, dried at 130 ° C. for 30 seconds, and dried at 1 g / m 2. ² Was provided.
[0089]
<Thermal layer solution>
(A) Near infrared absorbing dye "PROJET" 825 LDI (manufactured by Avecia): 11 parts by weight
(B) 2 parts of dye "OIL SCARLET 308" (manufactured by Orient Chemical Industry Co., Ltd.) having absorption in the visible region ("Isopar E," (solubility in Esso Chemical Co., Ltd. 0.005))
(C) Titanium di-n-butoxide bis (2,4-pentanedionate) "Nasem Titanium" (manufactured by Nippon Chemical Industry Co., Ltd.): 22 parts by weight
(D) Phenol novolak resin "Sumilite Resin" PR54652 (manufactured by Sumitomo Durez Co., Ltd.): 60 parts by weight
(E) Polyurethane "SAMPLEN" LQT1331D (manufactured by Sanyo Chemical Industries, Ltd.): 10 parts by weight
(F) m-xylylenediamine / glycidyl methacrylate / 3-glycidoxypropyltrimethoxysilane = 1/3/1 mole ratio Addition product: 15 parts by weight
(G) Tetrahydrofuran: 800 parts by weight
(H) dimethylformamide: 100 parts by weight
Next, the following silicone solution was applied by a slit die coater with a dry film thickness of 2.0 μm and drying conditions of 120 ° C. × 120 seconds to provide a silicone rubber layer.
[0090]
<Silicone rubber layer>
(A) α, ω-divinylpolydimethylsiloxane (molecular weight: about 60,000): 100 parts by weight
(B) HMS-501 (manufactured by Chisso Corporation, both ends methyl (methylhydrogensiloxane) (dimethylsiloxane) copolymer SiH group number / molecular weight = 0.69 mol / g): 7 parts by weight
(C) "BY24-808" (a reaction inhibitor manufactured by Toray Dow Corning Silicone Co., Ltd.): 3 parts by weight
(D) "SRX-212" (Toray Dow Corning Silicone Co., Ltd., platinum catalyst): 5 parts by weight
(E) Vinyl tri (methylethyl ketoxime) silane: 3 parts by weight
(F) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 1000 parts by weight
An 8 μm-thick polypropylene film “Trefane” BO (manufactured by Toray Industries, Inc.) was laminated as a cover film on the laminate obtained as described above using a calendar roller, and a direct-drawing waterless planographic printing plate precursor was used. Got.
[0091]
Thereafter, this printing plate precursor was mounted on “FX400-AP” (plate making machine, manufactured by Toray Engineering Co., Ltd.), and irradiation energy was 150 μJ / cm using a semiconductor laser (wavelength: 830 nm, beam diameter: 20 μm) with an exposure time of 10 μs and an irradiation time of 10 μs. ² Exposure was performed. Subsequently, an automatic developing machine “TWL-860KII” (manufactured by Toray Industries, Inc., pretreatment solution: NP-1 (manufactured by Toray Industries, Inc.), developing solution: water, post-processing solution: NA-1, manufactured by Toray Industries, Inc. )), The exposed plate was developed under the condition of a pre-processing time of 30 seconds to obtain a direct-drawing waterless planographic printing plate. Here, as a result of visually observing the cover film after peeling, no coloring by the dye was observed.
[0092]
<< Evaluation of image reproducibility >>
The obtained printing plate was attached to a sheet-fed offset printing machine “Sprint 25” (manufactured by Komori Corporation), and waterless lithographic ink “Dryocolor NSI”, indigo (manufactured by Dainippon Ink and Chemicals, Inc.) Was used to print on high quality paper (62.5 kg / chrysanthemum), and the image reproducibility of the printed matter was evaluated. As a result, 1 to 99% of halftone dots were reproduced, and good image reproducibility was obtained.
[0093]
<< Measurement of UV spectrum of printing plate >>
The UV absorption spectrum was measured using "Spectrophotometer U-3210" (manufactured by Hitachi, Ltd.). As a result, it had an absorption peak at about 520 nm, and the absorbance difference from that without the dye added (Comparative Example 1) was 0.35.
[0094]
<< Evaluation of plate inspection >>
The printing plate used for printing was removed from the printing press, and the printing plate was observed with a magnifying loupe of 25 times in a state where the printing plate was inked, thereby evaluating the plate inspection property. As a result, halftone dots of 1% could be easily confirmed, and it was found that the plate inspection property was good.
[0095]
Examples 2 to 5
A lithographic printing plate was prepared in exactly the same manner as in Example 1 except that the composition (b) “OIL SCARLET308” of the heat-sensitive layer was changed to the dye shown in Table 2. When the same evaluation as in Example 1 was performed, there was no coloring on the cover film, and both image reproducibility and plate inspection properties were good. In addition, each had an absorption peak in the visible light region of 450 to 600 nm, and the difference in absorbance from that in which no dye was added (Comparative Example 3) was 0.1 or more.
[0096]
Example 6
A printing plate precursor was prepared in exactly the same manner as in Example 1 except that the component (a) in the heat-sensitive layer was changed to "YKR-2900" (manufactured by Yamamoto Kasei Co., Ltd.) to obtain a direct-drawing lithographic printing plate. Was. When evaluated in the same manner as in Example 1, there was no coloring on the cover film, and both image reproducibility and plate inspection properties were good. In addition, as a result of measuring the UV absorption spectrum, the absorbance difference from that having no absorption dye at 515 nm (Comparative Example 4) was 0.30.
[0097]
Example 7
A printing plate precursor was prepared in exactly the same manner as in Example 1 except that the component (a) in the heat-sensitive layer was changed to "KAYASORB" PS101 (manufactured by Nippon Kayaku Co., Ltd.) to obtain a direct-drawing planographic printing plate. Was. When evaluated in the same manner as in Example 1, there was no coloring on the cover film and the image reproducibility was good. Further, as a result of observing the printing plate, it was possible to confirm up to 4% of halftone dots. As a result of measuring the UV absorption spectrum, the difference in absorbance from that having no absorption dye at 515 nm (Comparative Example 5) was 0.29.
[0098]
Example 8
A solution having the following composition was applied on a degreased aluminum plate having a thickness of 0.24 mm using a slit die coater, dried at 190 ° C. for 60 seconds, and 6.0 g / m 2. ² Was provided.
[0099]
(Production method of titanium oxide dispersion)
10 parts by weight of titanium oxide "CR-50" (manufactured by Ishihara Sangyo Co., Ltd.) was added to 10 parts by weight of dimethylformamide, and the mixture was stirred for 5 minutes. Further, 15 parts by weight of glass beads (No. 08) were added, and the mixture was vigorously stirred for 20 minutes, and the glass beads were removed to obtain a titanium oxide dispersion. Using this titanium oxide dispersion, the following solutions were further prepared.
[0100]
<Insulation layer solution 1>
(A) Epoxy resin “Epicoat” 1010 (manufactured by Yuka Shell Epoxy Co., Ltd.): 35 parts by weight
(B) Polyurethane "SAMPLEN" LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd.): 40 parts by weight
(C) Metal chelate “Aluminum chelate” ALCH-TR (manufactured by Kawaken Fine Chemical Co., Ltd.): 8 parts by weight
(D) Vinyl polymer "DISPARON" LC951 (manufactured by Kusumoto Kasei Co., Ltd.): 0.1 part by weight
(E) Titanium oxide dispersion: 72 parts by weight
(F) Dimethylformamide: 900 parts by weight.
[0101]
Next, a heat-sensitive layer solution having the following composition was applied by a slit die coater, dried at 130 ° C. for 30 seconds, and dried at 1.5 g / m 2. ² Was provided.
[0102]
<Thermal layer solution>
(A) Near infrared absorbing dye "PROJET" 825 LDI (manufactured by Avecia): 11 parts by weight
(B) Dye "Rhodamine 6GCP" having absorption in the visible region (manufactured by Taoka Chemical Industry Co., Ltd.) "Isoper E" (solubility in Esso Chemical Co., Ltd .: 0 g): 2 parts
(C) Titanium di-n-butoxide bis (2,4-pentanedionate) "Nasem Titanium" (manufactured by Nippon Chemical Industry Co., Ltd.): 22 parts by weight
(D) Phenol novolak resin "Sumilite Resin" PR54652 (manufactured by Sumitomo Durez Co., Ltd.): 60 parts by weight
(E) Polyurethane "SAMPLEN" LQT1331D (manufactured by Sanyo Chemical Industries, Ltd.): 10 parts by weight
(F) m-xylylenediamine / glycidyl methacrylate / 3-glycidoxypropyltrimethoxysilane = 1/3/1 mole ratio Addition product: 15 parts by weight
(G) Tetrahydrofuran: 800 parts by weight
(H) dimethylformamide: 100 parts by weight.
[0103]
Next, the following silicone solution was applied by a slit die coater with a dry film thickness of 2.0 μm and drying conditions of 120 ° C. × 120 seconds to provide a silicone rubber layer.
[0104]
<Silicone rubber layer>
(A) α, ω-divinylpolydimethylsiloxane (molecular weight: about 60,000): 100 parts by weight
(B) HMS-501 (manufactured by Chisso Corporation, both ends methyl (methylhydrogensiloxane) (dimethylsiloxane) copolymer SiH group number / molecular weight = 0.69 mol / g): 7 parts by weight
(C) "BY24-808" (a reaction inhibitor manufactured by Toray Dow Corning Silicone Co., Ltd.): 3 parts by weight
(D) "SRX-212" (Toray Dow Corning Silicone Co., Ltd., platinum catalyst): 5 parts by weight
(E) Vinyl tri (methylethyl ketoxime) silane: 3 parts by weight
(F) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 1000 parts by weight.
[0105]
When the same evaluation as in Example 1 was performed, there was no coloring on the cover film, and both image reproducibility and plate inspection properties were good. In addition, each had an absorption peak in the visible light region of 450 to 600 nm, and the difference in absorbance from that in which no dye was added (Comparative Example 3) was 0.5 or more.
[0106]
Comparative Example 1
A lithographic printing plate was prepared in exactly the same manner as in Example 1 except that the composition (b) of the heat-sensitive layer was changed to "OIL RED RR". When the same evaluation as in Example 1 was performed, the printed matter reproduced 1 to 99% of halftone dots, and the plate inspection property was good. However, as a result of checking the cover film, it was confirmed that the cover film was colored.
[0107]
Comparative Example 2
A lithographic printing plate was prepared in exactly the same manner as in Example 1 except that the composition (b) of the heat-sensitive layer was changed to "OIL RED 5B". When the same evaluation as in Example 1 was performed, the printed matter reproduced 1 to 99% of halftone dots, and the plate inspection property was good. However, as a result of checking the cover film, it was confirmed that the cover film was colored.
[0108]
Comparative Example 3
A lithographic printing plate was produced in exactly the same manner as in Example 1 except that (b) "OIL SCARLET 308" (manufactured by Orient Chemical Industries, Ltd.) was omitted from the composition of the heat-sensitive layer. When evaluated in the same manner as in Example 1, the printed matter reproduced 1 to 99% of halftone dots, and good image reproducibility was obtained. Further, as a result of observing the printing plate, it was possible to easily confirm the halftone dot of 1%, and the plate inspection property was good. Here, there was no absorption peak in the visible light region of 450 to 600 nm, and the value of the baseline was 0.05.
[0109]
Comparative Example 4
A lithographic printing plate was prepared in exactly the same manner as in Example 6, except that (b) "OIL SCARLET 308" (manufactured by Orient Chemical Industry Co., Ltd.) was omitted from the composition of the heat-sensitive layer. When evaluated in the same manner as in Example 1, the printed matter reproduced 1 to 99% of halftone dots, and good image reproducibility was obtained. Further, as a result of observing the printing plate, it was possible to easily confirm the halftone dot of 1%, and the plate inspection property was good. Here, there was no absorption peak in the visible light region of 450 to 600 nm, and the value of the baseline was 0.1.
[0110]
Comparative Example 5
A lithographic printing plate was produced in exactly the same manner as in Example 7 except that (b) “OIL SCARLET 308” (manufactured by Orient Chemical Industries, Ltd.) was omitted from the composition of the heat-sensitive layer. When evaluated in the same manner as in Example 1, the printed matter reproduced 1 to 99% of halftone dots, and good image reproducibility was obtained. Further, as a result of observing the printing plate, it was possible to confirm up to 4% of halftone dots. Here, there was no absorption peak in the visible light region of 450 to 600 nm, and the value of the baseline was 0.1.
[0111]
[Table 1]

[0112]
[Table 2]

[0113]
[Table 3]

[0114]
According to the present invention, a direct-drawing waterless lithographic printing plate precursor having excellent plate performance and various appearances can be obtained.

Claims (3)

A direct-drawing waterless lithographic printing plate precursor having at least a heat-sensitive layer and an ink repellent layer on a substrate, wherein the heat-sensitive layer contains (a) a light-to-heat conversion substance, and (b) an initial boiling point of 110 ° C. or more and A dye having an absorption peak in the visible light region having a solubility in an aliphatic hydrocarbon solvent having a dry point of 145 ° C. or less at room temperature of 25 ° C. of 0.01 g or less. Lithographic printing plate precursor without mold water. (A) The absorbance characteristic of the photothermal conversion substance is (1) the main peak of the absorption spectrum exists between 700 and 1200 nm, and (2) the ratio of the absorbance at 830 nm (A) to the absorbance at 650 nm (B): 2. The direct-drawing waterless planographic printing plate precursor according to claim 1, wherein (A / B) is 1.5 or more. The direct drawing type waterless lithographic printing plate precursor according to claim 1, wherein a solvent used for the ink repellent layer coating solution is an aliphatic hydrocarbon solvent.