JP2004306312A - Printing plate material, its image recording method and its printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing plate material free from deviation in size and deterioration in an initial inking property due to insufficient exposure, even if the printing plate material is subjected to exposure with a large sized exposure drum, an image recording method using the printing plate material, a manufacturing method of a printing plate and a printing method using the printing plate. <P>SOLUTION: In the printing plate material having an imaging forming layer on a plastic support in which an image recording device having an exposure drum of a diameter of 250 mm or more is used to irradiate a laser beam to form an image on the exposure drum, the printing material has a stiffness (ST) of 30g≤ST≤120g at 23°C, 48% RH. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１１７】
本発明では、糖類を含有する層を水溶液で塗布形成することが好ましいため、水溶液から形成された場合は、層中に存在するオリゴ糖が水和物を形成するオリゴ糖である場合は、その融点は水和物の融点であると考えられる。このように、比較的低融点を有しているため、熱溶融微粒子が溶融する温度範囲や熱融着微粒子が融着する温度範囲でオリゴ糖も溶融し、熱溶融微粒子の多孔質な構造を有する親水性層への溶融浸透や熱融着微粒子の融着といった画像形成を妨げることがない。
【０１１８】
オリゴ糖の中でもトレハロースは、比較的純度の高い状態のものが工業的に安価に入手可能であり、水への溶解度が高いにもかかわらず、吸湿性は非常に低く、機上現像性及び保存性共に非常に良好である。
【０１１９】
又、オリゴ糖水和物を熱溶融させて水和水を除去した後に凝固させると（凝固後短時間のうちは）無水物の結晶となるが、トレハロースは水和物よりも無水物の融点が１００℃以上も高いことが特徴的である。これは赤外線露光で熱溶融し、再凝固した直後は露光された部分は高融点で溶融しにくい状態となることを意味し、バンディング等の露光時の画像欠陥を起こしにくくする効果がある。本発明の目的を達成するには、オリゴ糖の中でも特にトレハロースが好ましい。
【０１２０】
構成層中のオリゴ糖の含有量としては、層全体の１〜９０質量％が好ましく、１０〜８０質量％がさらに好ましい。
【０１２１】
また本発明に係る画像形成機能層は、後述する光熱変換素材を含有させることが好ましい。
【０１２２】
画像形成機能層の乾燥塗布質量は好ましくは０．１０〜０．７５ｇ／ｍ^２、より好ましくは０．１５〜０．５０ｇ／ｍ^２である。
【０１２３】
〈親水性オーバーコート層〉
本発明において、取り扱い時の傷つき防止のために、画像形成機能層の上層に親水性オーバーコート層を有することが好ましい。親水性オーバーコート層は画像形成機能層のすぐ上の層であってもよいし、また画像形成機能層と親水性オーバーコート層の間に中間層が設けられてもよい。親水性オーバーコート層は印刷機上で除去可能であることが好ましい。
【０１２４】
本発明において親水性オーバーコート層は、水溶性樹脂又は水溶性樹脂を部分的に架橋した水膨潤性樹脂を含有することが好ましい。かかる水溶性樹脂は、画像形成機能層に含有されるものが用いられる。
【０１２５】
本発明においては、親水性オーバーコート層は、後述する光熱変換素材を含有することができる。
【０１２６】
またレーザー記録装置あるいは印刷機に本発明の印刷版を装着するときの傷つき防止のために、本発明においてオーバーコート層に平均粒径１μｍ以上２０μｍ未満のマット剤を含有させることが好ましい。
【０１２７】
好ましく用いられるマット剤としては新モース硬度５以上の無機微粒子や有機マット剤があげられる。新モース硬度５以上の無機微粒子としては、例えば金属酸化物粒子（シリカ、アルミナ、チタニア、ジルコニア、酸化鉄、酸化クロム等）や金属炭化物粒子（炭化珪素等）、窒化ホウ素粒子、ダイアモンド粒子等が挙げられる。有機マット剤としては、例えば米国特許第２，３２２，０３７号明細書等に記載の澱粉、ＢＥ６２５，４５１号やＧＢ９８１，１９８号明細書等に記載された澱粉誘導体、特公昭４４−３６４３号公報等に記載のポリビニルアルコール、ＣＨ３３０，１５８号明細書等に記載のポリスチレン或いはポリメタアクリレート、米国特許第３，０７９，２５７号等明細書に記載のポリアクリロニトリル、米国特許第３，０２２，１６９号明細書等に記載されたポリカーボネートがあげられる。
【０１２８】
これらマット剤の添加量は１ｍ^２あたり０．１ｇ以上１０ｇ未満であることが好ましい。
【０１２９】
その他、オーバーコート層には塗布の均一性を確保する目的で、水溶液塗布の場合には主に非イオン系界面活性剤を添加することができる。この様な非イオン界面活性剤の具体例としては、ソルビタントリステアレート、ソルビタンモノパルミテート、ソルビタントリオレート、ステアリン酸モノグリセリド、ポリオキシエチレンノニルフェニルエーテル、ポリオキシエチレンドデシルエーテル等を挙げることができる。上記非イオン界面活性剤のオーバーコート層の全固形物中に占める割合は、０．０５〜５質量％が好ましく、より好ましくは１〜３質量％である。
【０１３０】
本発明において、オーバーコート層の乾燥塗布量は、０．０５〜１．５ｇ／ｍ^２が好ましく、更に好ましい範囲は０．１〜０．７ｇ／ｍ^２である。この範囲内で、印刷機上でのオーバーコート層の除去性を損なうことなく、良好な汚れ防止、傷付き防止、指紋跡付着防止およびアブレーションカスの発生低減ができる。
【０１３１】
〈親水性層〉
本発明の印刷版材料は、画像形成機能層を有し、かつ支持体と該画像形成機能層の間に少なくとも１層の親水性層を有する構成をとっているが、ここで、本発明に係る、支持体と該画像形成機能層の間に設けられる親水性層について説明する。親水性層とは、本発明の印刷版材料を印刷版として用いる際に、インキに対する親和性が低く、且つ、水に対する親和性の高い層として定義される。
【０１３２】
請求項４に記載のように、本発明の印刷版材料は、支持体上に設けられた親水性層の少なくとも１層が、多孔質構造を有することが好ましい。前記多孔質構造を有する親水性層を形成するためには、下記に記載の親水性マトリクスを形成する素材が好ましく用いられる。
【０１３３】
（金属酸化物）
親水性マトリクスを形成する素材としては、金属酸化物が好ましい。金属酸化物としては、金属酸化物微粒子を含むことが好ましく、例えば、コロイダルシリカ、アルミナゾル、チタニアゾル、その他の金属酸化物のゾルが挙げられる。該金属酸化物微粒子の形態としては、球状、針状、羽毛状、その他の何れの形態でも良く、平均粒径としては、３〜１００ｎｍの範囲が好ましく、平均粒径が異なる数種の金属酸化物微粒子を併用することもできる。また、粒子表面に表面処理がなされていても良い。
【０１３４】
上記金属酸化物微粒子は、その造膜性を利用して結合剤としての使用が可能である。有機の結合剤を用いるよりも親水性の低下が少なく、親水性層への使用に適している。
【０１３５】
（コロイダルシリカ）
中でも、コロイダルシリカが特に好ましく使用できる。コロイダルシリカは、比較的低温の乾燥条件であっても造膜性が高いという利点があり、良好な強度を得ることができる。コロイダルシリカとしては、後述するネックレス状コロイダルシリカ、平均粒径２０ｎｍ以下の微粒子コロイダルシリカを含むことが好ましく、更に、コロイダルシリカはコロイド溶液としてアルカリ性を呈することが好ましい。
【０１３６】
ネックレス状コロイダルシリカとは、一次粒子径がｎｍのオーダーである球状シリカの水分散系の総称であり、一次粒粒子径が１０〜５０ｎｍの球状コロイダルシリカが５０〜４００ｎｍの長さに結合した「パールネックレス状」のコロイダルシリカを意味する。
【０１３７】
パールネックレス状（即ち真珠ネックレス状）とは、コロイダルシリカのシリカ粒子が連なって結合した状態のイメージが、真珠ネックレスの様な形状をしていることを意味している。
【０１３８】
ネックレス状コロイダルシリカを構成するシリカ粒子同士の結合は、シリカ粒子表面に存在する−ＳｉＯＨ基が脱水結合した−Ｓｉ−Ｏ−Ｓｉ−と推定される。ネックレス状のコロイダルシリカとしては、具体的には日産化学工業社製の「スノーテックス−ＰＳ」シリーズなどが挙げられ、製品名としては「スノーテックス−ＰＳ−Ｓ（連結した状態の平均粒子径は１１０ｎｍ程度）」、「スノーテックス−ＰＳ−Ｍ（連結した状態の平均粒子径は１２０ｎｍ程度）」及び「スノーテックス−ＰＳ−Ｌ（連結した状態の平均粒子径は１７０ｎｍ程度）」があり、これらに各々対応する酸性の製品が「スノーテックス−ＰＳ−Ｓ−Ｏ」、「スノーテックス−ＰＳ−Ｍ−Ｏ」及び「スノーテックス−ＰＳ−Ｌ−Ｏ」である。
【０１３９】
ネックレス状コロイダルシリカを添加することにより、層の多孔性を確保しつつ、強度を維持することが可能となり、親水性層マトリクスの多孔質化材として好ましく使用できる。これらの中でも、アルカリ性である「スノーテックスＰＳ−Ｓ」、「スノーテックスＰＳ−Ｍ」、「スノーテックスＰＳ−Ｌ」を用いると、親水性層の強度が向上し、また、印刷枚数が多い場合でも地汚れの発生が抑制され、特に好ましい。
【０１４０】
また、コロイダルシリカは、粒子径が小さいほど結合力が強くなることが知られており、本発明では平均粒径が２０ｎｍ以下であるコロイダルシリカを用いることが好ましく、更に好ましくは、３〜１５ｎｍのものである。
【０１４１】
前述のようにコロイダルシリカの中ではアルカリ性のものが、地汚れ発生を抑制する効果が高く特に好ましい。平均粒径がこの範囲にあるアルカリ性のコロイダルシリカとしては、例えば、日産化学社製の「スノーテックス−２０（粒子径１０〜２０ｎｍ）」、「スノーテックス−３０（粒子径１０〜２０ｎｍ）」、「スノーテックス−４０（粒子径１０〜２０ｎｍ）」、「スノーテックス−Ｎ（粒子径１０〜２０ｎｍ）」、「スノーテックス−Ｓ（粒子径８〜１１ｎｍ）」、「スノーテックス−ＸＳ（粒子径４〜６ｎｍ）」が挙げられる。
【０１４２】
平均粒径が２０ｎｍ以下であるコロイダルシリカは、前述のネックレス状コロイダルシリカと併用することで、形成する層の多孔質性を維持しながら、強度をさらに向上させることが可能となり、特に好ましい。
【０１４３】
平均粒径が２０ｎｍ以下であるコロイダルシリカ／ネックレス状コロイダルシリカの比率は９５／５〜５／９５の範囲が好ましく、更に好ましくは、７０／３０〜２０／８０の範囲がより好ましく、６０／４０〜３０／７０の範囲が更に好ましい。
【０１４４】
（多孔質金属酸化物粒子）
本発明において、親水性層マトリクス構造の多孔質化材として、粒径が１μｍ未満の多孔質金属酸化物粒子を含有することができる。多孔質金属酸化物粒子としては、以下に記載の多孔質シリカ、多孔質アルミノシリケート粒子または、ゼオライト粒子を好ましく用いることができる。
【０１４５】
（多孔質シリカ多孔質シリカ、多孔質アルミノシリケート粒子）
多孔質シリカ粒子は、一般に湿式法または、乾式法により製造される。湿式法では、ケイ酸塩水溶液を中和して得られるゲルを乾燥、粉砕するか、もしくは中和して析出した沈降物を粉砕することで得ることができる。乾式法では、四塩化珪素を水素と酸素と共に燃焼し、シリカを析出することで得られる。これらの粒子は製造条件の調整により、多孔性や粒径を制御することが可能である。多孔質シリカ粒子としては、湿式法のゲルから得られるものが特に好ましい。
【０１４６】
多孔質アルミノシリケート粒子は、例えば、特開平１０−７１７６４号公報に記載されている方法により製造される。即ち、アルミニウムアルコキシドと珪素アルコキシドを主成分として加水分解法により合成された非晶質な複合体粒子である。粒子中のアルミナとシリカの比率は１：４〜４：１の範囲で合成することが可能である。また、製造時にその他の金属のアルコキシドを添加して３成分以上の複合体粒子として製造したものも本発明に使用できる。これらの複合体粒子も製造条件の調整により多孔性や粒径を制御することが可能である。
【０１４７】
粒子の多孔性としては、細孔容積で０．５ｍｌ／ｇ以上であることが好ましく、０．８ｍｌ／ｇ以上であることがより好ましく、１．０〜２．５ｍｌ／ｇであることが更に好ましい。細孔容積は、塗膜の保水性と密接に関連しており、細孔容積が大きいほど保水性が良好となって印刷時に汚れにくく、水量ラチチュードも広くなるが、２．５ｍｌ／ｇよりも大きくなると粒子自体が非常に脆くなるため塗膜の耐久性が低下する。逆に、細孔容積が０．５ｍｌ／ｇ未満の場合には、印刷性能がやや不十分となる場合がある。
【０１４８】
（細孔容積の測定方法）
ここで、上記の細孔容積の測定は、オートソーブ−１（カンタクローム社製）を使用し、定容法を用いた窒素吸着測定により、粉体の空隙が窒素により、充填されていると仮定して相対圧力が０．９９８における窒素吸着量から算出されるものである。
【０１４９】
（ゼオライト粒子）
ゼオライトは、結晶性のアルミノケイ酸塩であり、細孔径が０．３ｎｍ〜１ｎｍの規則正しい三次元網目構造の空隙を有する多孔質体である。天然及び合成ゼオライトを合わせた一般式は、次のように表される。
【０１５０】
（Ｍ_１、（Ｍ_２）_０．５）_ｍ（Ａｌ_ｍＳｉ_ｎＯ_２）_{（ｍ＋ｎ）}・ｘＨ_２Ｏ
ここで、Ｍ_１、Ｍ_２は交換性のカチオンであって、Ｍ_１はＬｉ^＋、Ｎａ^＋、Ｋ^＋、Ｔｌ^＋、Ｍｅ_４Ｎ^＋（ＴＭＡ）、Ｅｔ_４Ｎ^＋（ＴＥＡ）、Ｐｒ_４Ｎ^＋（ＴＰＡ）、Ｃ_７Ｈ_１５Ｎ^２＋、Ｃ_８Ｈ_１６Ｎ^＋等であり、Ｍ_２はＣａ^２＋、Ｍｇ^２＋、Ｂａ^２＋、Ｓｒ^２＋、Ｃ_８Ｈ_１８Ｎ_２ ^２＋等である。また、ｎ≧ｍであり、ｍ／ｎの値つまりはＡｌ／Ｓｉ比率は１以下となる。Ａｌ／Ｓｉ比率が高いほど交換性カチオンの量が多く含まれるため極性が高く、従って親水性も高い。好ましいＡｌ／Ｓｉ比率は０．４〜１．０であり、更に好ましくは０．８〜１．０である。ｘは整数を表す。
【０１５１】
本発明で使用するゼオライト粒子としては、Ａｌ／Ｓｉ比率が安定しており、又粒径分布も比較的シャープである合成ゼオライトが好ましく、例えばゼオライトＡ：Ｎａ_１２（Ａｌ_１２Ｓｉ_１２Ｏ_４８）・２７Ｈ_２Ｏ；Ａｌ／Ｓｉ比率１．０、ゼオライトＸ：Ｎａ_８６（Ａｌ_８６Ｓｉ_１０６Ｏ_３８４）・２６４Ｈ_２Ｏ；Ａｌ／Ｓｉ比率０．８１１、ゼオライトＹ：Ｎａ_５６（Ａｌ_５６Ｓｉ_１３６Ｏ_３８４）・２５０Ｈ_２Ｏ；Ａｌ／Ｓｉ比率０．４１２等が挙げられる。
【０１５２】
Ａｌ／Ｓｉ比率が０．４〜１．０である親水性の高い多孔質粒子を含有することで、親水性層自体の親水性も大きく向上し、印刷時に汚れにくく、水量ラチチュードも広くなる。また、指紋跡の汚れも大きく改善される。Ａｌ／Ｓｉ比率が０．４未満では親水性が不充分であり、上記性能の改善効果が小さくなる。
【０１５３】
また、親水層を構成する親水性層マトリクス構造は、層状粘土鉱物粒子を含有することができる。該層状鉱物粒子としては、例えば、カオリナイト、ハロイサイト、タルク、スメクタイト（モンモリロナイト、バイデライト、ヘクトライト、サボナイト等）、バーミキュライト、マイカ（雲母）、クロライトといった粘土鉱物及び、ハイドロタルサイト、層状ポリケイ酸塩（カネマイト、マカタイト、アイアライト、マガディアイト、ケニヤアイト等）等が挙げられる。特に、単位層（ユニットレイヤー）の電荷密度が高いほど極性が高く、親水性も高いと考えられる。好ましい電荷密度としては０．２５以上、更に好ましくは０．６以上である。このような電荷密度を有する層状鉱物としては、スメクタイト（電荷密度０．２５〜０．６；陰電荷）、バーミキュライト（電荷密度０．６〜０．９；陰電荷）等が挙げられる。特に、合成フッ素雲母は粒径等安定した品質のものを入手することができ好ましい。また、合成フッ素雲母の中でも、膨潤性のものが好ましく、自由膨潤であるものが更に好ましい。
【０１５４】
また、上記の層状鉱物のインターカレーション化合物（ピラードクリスタル等）や、イオン交換処理を施したもの、表面処理（シランカップリング処理、有機バインダとの複合化処理等）を施したものも使用することができる。
【０１５５】
平板状層状鉱物粒子のサイズとしては、層中に含有されている状態で（膨潤工程、分散剥離工程を経た場合も含めて）、平均粒径（粒子の最大長）が１μｍ未満であり、平均アスペクト比が５０以上であることが好ましい。粒子サイズが上記範囲にある場合、薄層状粒子の特徴である平面方向の連続性及び柔軟性が塗膜に付与され、クラックが入りにくく乾燥状態で強靭な塗膜とすることができる。また、粒子物を多く含有する塗布液においては、層状粘土鉱物の増粘効果によって、粒子物の沈降を抑制することができる。粒子径が上記範囲より大きくなると、塗膜に不均一性が生じて、局所的に強度が弱くなる場合がある。また、アスペクト比が上記範囲以下である場合、添加量に対する平板状の粒子数が少なくなり、増粘性が不充分となり、粒子物の沈降を抑制する効果が低減する。
【０１５６】
層状鉱物粒子の含有量としては、層全体の０．１〜３０質量％であることが好ましく、１〜１０質量％であることがより好ましい。特に膨潤性合成フッ素雲母やスメクタイトは少量の添加でも効果が見られるため好ましい。層状鉱物粒子は、塗布液に粉体で添加してもよいが、簡便な調液方法（メディア分散等の分散工程を必要としない）でも良好な分散度を得るために、層状鉱物粒子を単独で水に膨潤させたゲルを調製した後、塗布液に添加することが好ましい。
【０１５７】
親水層を構成する親水性層マトリクスにはその他の添加素材として、ケイ酸塩水溶液も使用することができる。ケイ酸Ｎａ、ケイ酸Ｋ、ケイ酸Ｌｉといったアルカリ金属ケイ酸塩が好ましく、そのＳｉＯ_２／Ｍ_２Ｏ比率はケイ酸塩を添加した際の塗布液全体のｐＨが１３を超えない範囲となるように選択することが無機粒子の溶解を防止する上で好ましい。
【０１５８】
また、金属アルコキシドを用いた、いわゆるゾル−ゲル法による無機ポリマーもしくは有機−無機ハイブリッドポリマーも使用することができる。ゾル−ゲル法による無機ポリマーもしくは有機−無機ハイブリッドポリマーの形成については、例えば、「ゾル−ゲル法の応用」（作花済夫著／アグネ承風社発行）に記載されているか、又は本書に引用されている文献に記載されている公知の方法を使用することができる。
【０１５９】
また、本発明では、水溶性樹脂を含有してもよい。水溶性樹脂としては、例えば、多糖類、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリビニルアルコール、ポリエチレングリコール（ＰＥＧ）、ポリビニルエーテル、スチレン−ブタジエン共重合体、メチルメタクリレート−ブタジエン共重合体の共役ジエン系重合体ラテックス、アクリル系重合体ラテックス、ビニル系重合体ラテックス、ポリアクリル酸ナトリウム、ポリアクリルアミド、ポリビニルピロリドン等の樹脂が挙げられるが、本発明に用いられる水溶性樹脂としては、多糖類またはポリアクリル酸ナトリウム、を用いることが好ましい。
【０１６０】
多糖類としては、デンプン類、セルロース類、ポリウロン酸、プルランなどが使用可能であるが、特にメチルセルロース塩、カルボキシメチルセルロース塩、ヒドロキシエチルセルロース塩等のセルロース誘導体が好ましく、カルボキシメチルセルロースのナトリウム塩やアンモニウム塩がより好ましい。これは、親水性層に多糖類を含有させることにより、親水性層の表面形状を好ましい状態形成する効果が得られるためである。
【０１６１】
親水性層の表面は、ＰＳ版のアルミ砂目のように０．１〜２０μｍピッチの凹凸構造を有することが好ましく、この凹凸により保水性や画像部の保持性が向上する。このような凹凸構造は、親水性層マトリクスに適切な粒径のフィラーを適切な量含有させて形成することも可能であるが、親水性層の塗布液に前述のアルカリ性コロイダルシリカと前述の水溶性多糖類とを含有させ、親水性層を塗布、乾燥させる際に相分離を生じさせて形成することがより良好な印刷適性を有する構造を得ることができ、好ましい。
【０１６２】
凹凸構造の形態（ピッチ及び表面粗さなど）は、アルカリ性コロイダルシリカの種類及び添加量、水溶性多糖類の種類及び添加量、その他添加材の種類及び添加量、塗布液の固形分濃度、ウエット膜厚、乾燥条件等で適宜コントロールすることが可能である。
【０１６３】
本発明において、親水性マトリクス構造部に添加される水溶性樹脂は、少なくともその一部が水溶性の状態のまま、水に溶出可能な状態で存在することが好ましい。水溶性の素材であっても、架橋剤等によって架橋し、水に不溶の状態になると、その親水性は低下して印刷適性を劣化させる懸念があるためである。また、さらにカチオン性樹脂を含有しても良く、カチオン性樹脂としては、例えば、ポリエチレンアミン、ポリプロピレンポリアミン等のようなポリアルキレンポリアミン類又はその誘導体、第３級アミノ基や第４級アンモニウム基を有するアクリル樹脂、ジアクリルアミン等が挙げられる。カチオン性樹脂は、微粒子状の形態で添加しても良く、例えば、特開平６−１６１１０１号公報に記載のカチオン性マイクロゲルが挙げられる。
【０１６４】
また、本発明に係る親水性層を塗設する為に用いられる塗布液には、塗布性改善等の目的で水溶性の界面活性剤を含有させることができ、Ｓｉ系または、Ｆ系等の界面活性剤を使用することができるが、特にＳｉ元素を含む界面活性剤を使用することが印刷汚れを生じる懸念がなく、好ましい。該界面活性剤の含有量は、親水性層全体（塗布液としては固形分）の０．０１〜３質量％が好ましく、０．０３〜１質量％が更に好ましい。
【０１６５】
また、親水性層には、リン酸塩を含むことができる。本発明では、親水性層の塗布液がアルカリ性であることが好ましいため、リン酸塩としてはリン酸三ナトリウムやリン酸水素二ナトリウムとして添加することが好ましい。リン酸塩を添加することで、印刷時の網の目開きを改善する効果が得られる。リン酸塩の添加量としては、水和物を除いた有効量として、０．１〜５質量％が好ましく、０．５〜２質量％が更に好ましい。
【０１６６】
また、後述する光熱変換素材を含有することもできる。本発明においては、親水性層は支持体と画像形成機能層の間に配置され、かつ、親水性層の乾燥固形分量が１ｍ^２あたり０．５〜５ｇであることが好ましい。親水性層は１層でも複数層でもよく、複数層の場合は、各層の固形分の合計量が上記の範囲になる。
【０１６７】
〈光熱変換素材〉
本発明に係る画像形成機能層、親水性層、親水性オーバーコート層及びその他に設けられる層には、光熱変換素材を含有することが好ましい。
【０１６８】
光熱変換素材としては赤外吸収色素または顔料を添加することができる。
（赤外吸収色素）
一般的な赤外吸収色素であるシアニン系色素、クロコニウム系色素、ポリメチン系色素、アズレニウム系色素、スクワリウム系色素、チオピリリウム系色素、ナフトキノン系色素、アントラキノン系色素などの有機化合物、フタロシアニン系、ナフタロシアニン系、アゾ系、チオアミド系、ジチオール系、インドアニリン系の有機金属錯体などが挙げられる。具体的には、特開昭６３−１３９１９１号、特開昭６４−３３５４７号、特開平１−１６０６８３号、特開平１−２８０７５０号、特開平１−２９３３４２号、特開平２−２０７４号、特開平３−２６５９３号、特開平３−３０９９１号、特開平３−３４８９１号、特開平３−３６０９３号、特開平３−３６０９４号、特開平３−３６０９５号、特開平３−４２２８１号、特開平３−９７５８９号、特開平３−１０３４７６号、特開平７−４３８５１号、特開平７−１０２１７９号、特開２００１−１１７２０１の各公報等に記載の化合物が挙げられる。これらは一種又は二種以上を組み合わせて用いることができる。
【０１６９】
顔料としては、カーボン、グラファイト、金属、金属酸化物等が挙げられる。カーボンとしては特にファーネスブラックやアセチレンブラックの使用が好ましい。粒度（ｄ５０）は１００ｎｍ以下であることが好ましく、５０ｎｍ以下であることが更に好ましい。
【０１７０】
グラファイトとしては粒径が０．５μｍ以下、好ましくは１００ｎｍ以下、更に好ましくは５０ｎｍ以下の微粒子を使用することができる。
【０１７１】
金属としては粒径が０．５μｍ以下、好ましくは１００ｎｍ以下、更に好ましくは５０ｎｍ以下の微粒子であれば何れの金属であっても使用することができる。形状としては球状、片状、針状等何れの形状でも良い。特にコロイド状金属微粒子（Ａｇ、Ａｕ等）が好ましい。
【０１７２】
金属酸化物としては、可視光域で黒色を呈している素材、または素材自体が導電性を有するか、半導体であるような素材を使用することができる。可視光域で黒色を呈している素材しては、黒色酸化鉄（Ｆｅ_３Ｏ_４）や、前述の二種以上の金属を含有する黒色複合金属酸化物が挙げられる。金属酸化物が二種以上の金属の酸化物からなる黒色複合金属酸化物であることである。具体的には、Ａｌ、Ｔｉ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｓｂ、Ｂａから選ばれる二種以上の金属からなる複合金属酸化物である。これらは、特開平８−２７３９３号公報、特開平９−２５１２６号公報、特開平９−２３７５７０号公報、特開平９−２４１５２９号公報、特開平１０−２３１４４１号公報等に開示されている方法により製造することができる。本発明に用いることができる複合金属酸化物としては、特にＣｕ−Ｃｒ−Ｍｎ系またはＣｕ−Ｆｅ−Ｍｎ系の複合金属酸化物であることが好ましい。Ｃｕ−Ｃｒ−Ｍｎ系の場合には、６価クロムの溶出を低減させるために、特開平８−２７３９３号公報に開示されている処理を施すことが好ましい。これらの複合金属酸化物は添加量に対する着色、つまり、光熱変換効率が良好である。これらの複合金属酸化物は平均１次粒子径が１μｍ以下であることが好ましく、平均１次粒子径が０．０１〜０．５μｍの範囲にあることがより好ましい。平均１次粒子径が１μｍ以下とすることで、添加量に対する光熱変換能がより良好となり、平均１次粒子径が０．０１〜０．５μｍの範囲とすることで添加量に対する光熱変換能がより良好となる。ただし、添加量に対する光熱変換能は、粒子の分散度にも大きく影響を受け、分散が良好であるほど良好となる。従って、これらの複合金属酸化物粒子は、層の塗布液に添加する前に、別途公知の方法により分散して、分散液（ペースト）としておくことが好ましい。平均１次粒子径が０．０１未満となると分散が困難となるため好ましくない。分散には適宜分散剤を使用することができる。分散剤の添加量は複合金属酸化物粒子に対して０．０１〜５質量％が好ましく、０．１〜２質量％がより好ましい。分散剤の種類は特に限定しないが、Ｓｉ元素を含むＳｉ系界面活性剤を用いることが好ましい。
【０１７３】
素材自体が導電性を有するか、半導体であるような素材としては、例えばＳｂをドープしたＳｎＯ_２（ＡＴＯ）、Ｓｎを添加したＩｎ_２Ｏ_３（ＩＴＯ）、ＴｉＯ２、ＴｉＯ_２を還元したＴｉＯ（酸化窒化チタン、一般的にはチタンブラック）などが挙げられる。また、これらの金属酸化物で芯材（ＢａＳＯ_４、ＴｉＯ_２、９Ａｌ_２Ｏ_３・２Ｂ_２Ｏ、Ｋ_２Ｏ・ｎＴｉＯ_２等）を被覆したものも使用することができる。これらの粒径は、０．５μｍ以下、好ましくは１００ｎｍ以下、更に好ましくは５０ｎｍ以下である。
【０１７４】
特に好ましい光熱変換素材の態様としては、前記の赤外吸収色素および金属酸化物が二種以上の金属の酸化物からなる黒色複合金属酸化物であることである。
【０１７５】
これらの光熱変換素材の添加量としては、各層に対して０．１〜５０質量％であり、１〜３０質量％が好ましく、３〜２５質量％がより好ましい。
【０１７６】
〈可視画性の付与〉
通常、印刷業界においては、印刷材料に画像形成した印刷版を印刷する前に、正しく画像が形成されているかを検査する検版という作業がある。検版をするためには、印刷前に形成された画像が版面上で見える性能、つまり可視画性が良いことが好ましい。本発明の印刷版材料は、現像処理なしに印刷可能なプロセスレス印刷版材料なので、露光することによる光または熱によって露光部分または未露光部分の光学濃度が変化することが好ましい。
【０１７７】
本発明において好ましく用いられる方法としては、露光することにより光学濃度が変化するシアニン系赤外線吸収色素を含有する方法、光酸発生剤とその酸により変色する化合物を用いる方法、ロイコ色素のような発色剤と顕色剤を組み合わせて用いる方法などがある。
【０１７８】
本発明において、光酸発生剤とは、露光によってルイス酸やブレンステッド酸を生成する化合物を意味する。
【０１７９】
光酸発生剤の具体例としては、ジアゾ化合物、オルトキノンジアジド化合物、ポリハロゲン化合物、オニウム塩化合物などが挙げられる。またこれらの構造をポリマーに組み込んだ化合物を用いることもできる。
【０１８０】
ジアゾ化合物としては、例えば、米国特許２，０６３，６３１号明細書、米国特許２，６６７，４１５号明細書などに開示されているジアゾニウム塩とアルドールやアセタールなどの反応性カルボニル基を含有する有機結合剤との反応生成物であるジフェニルアミン−ｐ−ジアゾニウム塩とフォルムアルデヒド縮合生成物、またこれらの水溶性ジアゾニウム塩化合物を特開昭５４−９８６１３号公報に開示された方法により、ＢＦ^４−、ＰＦ^６−などのアニオン成分などで置換したハロゲン化ルイス酸塩、アリルジアゾニウム塩化合物などが挙げられる。
【０１８１】
オルトキノンジアジド化合物としては、１分子中に少なくともひとつのオルトキノンジアジド基を有する化合物で、１，２−ナフトキノン−２−ジアジド−５−スルフォン酸−エチルエステル、１，２−ナフトキノン−２−ジアジド−５−スルフォン酸−イソブチルエステル、１，２−ナフトキノン−２−ジアジド−５−スルフォン酸−フェニルエステル、１，２−ナフトキノン−２−ジアジド−５−スルフォン酸−α−ナフチルエステル、１，２−ナフトキノン−２−ジアジド−５−スルフォン酸−ベンジルエステル、１，２−ナフトキノン−２−ジアジド−４−スルフォン酸−フェニルエステル、１，２−ナフトキノン−２−ジアジド−４−スルフォン酸−エチルアミド、１，２−ナフトキノン−２−ジアジド−４−スルフォン酸−フェニルアミドなどが挙げられる。
【０１８２】
ポリハロゲン化合物としては、ポリハロゲンを含むアセトフェノン、例えばトリブロモアセトフェノン、トリクロロアセトフェノン、ｏ−ニトロ−トリブロモアセトフェノン、ｐ−ニトロ−トリブロモアセトフェノン、ｍ−ニトロ−トリブロモアセトフェノン、ｍ−ブロモ−トリブロモアセトフェノン、ｐ−ブロモ−トリブロモアセトフェノンなど、また、ポリハロゲンを含むスルフォキサイド、例えばビス（トリブロモメチル）スルフォキサイド、ジブロモメチル−トリブロモメチルスルフォキサイド、トリブロモメチル−フェニルスルフォキサイドなど、またポリハロゲンを含むスルフォン、例えばビス（トリブロモメチル）スルフォン、トリクロロメチル−フェニルスルフォン、トリブロモメチル−フェニルスルフォン、トリクロロメチル−ｐ−クロロフェニルスルフォン、トリブロモメチル−ｐ−ニトロフェニルスルフォン２−トリクロロメチルベンゾチアゾールスルフォン、２，４−ジクロロフェニル−トリクロロメチルスルフォンなど、その他ポリハロゲンを含むピロン化合物、トリアジン化合物、オキサジアゾール化合物などが挙げられる。
【０１８３】
オニウム塩化合物およびその他の光酸発生剤としては、Ｓ．Ｐ．Ｐａｐａｓ，ｅｔ ａｌ．，Ｐｏｌｙｍ．Ｐｈｏｔｏｃｈｅｍ．，５，１，ｐ１０４〜１１５（１９８４）に記載されているオニウム塩化合物、また色材、６６（２）、ｐ１０４〜１１５（１９９３）に紹介されている、Ｐｈ_２Ｉ^＋／ＳｂＦ^６−等のジアリルヨードニウム塩化合物に代表される光酸発生剤、トリアリルスルフォニウム塩化合物、トリアリルセレノニウム塩化合物、ジアルキルフェナシルスルフォニウム塩化合物、ジアルキル−４−フェナシルスルフォニウム塩化合物、α−ヒドロキシメチルベンゾインスルフォン酸エステル、Ｎ−ヒドロキシイミノスルフォネート、α−スルフォニロキシケトン、β−スルフォニロキシケトン、鉄−アレーン錯体化合物（ベンゼン−シクロペンタジエニル−鉄（ＩＩ）ヘキサフルオロフォスフェートなど）、ｏ−ニトロベンジルシリルエーテル化合物、ベンゾイントシレート、トリ（ニトロベンジル）フォスフェートなどが挙げられる。
【０１８４】
その他に、アンモニウム塩、ホスホニウム塩、ヨードニウム塩、スルホニウム塩、セレノニウム塩、アルソニウム塩、有機ハロゲン化合物、ｏ−ニトロベンジル誘導体、イミノスルホネート及びジスルホン化合物等を挙げることができる。
【０１８５】
さらに具体的には、例えば、特開平９−２４４２２６号公報の化７〜化９に記載のＴ−１〜Ｔ−１５の式で示される化合物を挙げることができる。
【０１８６】
これらの中、より好ましいものはトリハロメチル基を２個以上有するｓ−トリアジン化合物であり、特に好ましくはトリス（トリクロロメチル）−ｓ−トリアジンである。これら光酸発生剤の含有量は、印刷版材料の全固形分に対し、０．０１〜４０質量％、好ましくは０．１〜３０質量％である。
【０１８７】
本発明において、酸によって変色する化合物としては、例えばジフェニルメタン、トリフェニルメタン系、チアジン系、オキサジン系、キサンテン系、アンスラキノン系、イミノキノン系、アゾ系、アゾメチン系等の各種色素が有効に用いられる。
【０１８８】
具体例としては、ブリリアントグリーン、エチルバイオレット、メチルグリーン、クリスタルバイオレット、ベイシックフクシン、メチルバイオレット２Ｂ、キナルジンレッド、ローズベンガル、メタニルイエロー、チモールスルホフタレイン、キシレノールブルー、メチルオレンジ、パラメチルレッド、コンゴーフレッド、ベンゾプルプリン４Ｂ、α−ナフチルレッド、ナイルブルー２Ｂ、ナイルブルーＡ、メチルバイオレット、マラカイドグリーン、パラフクシン、ビクトリアピュアブルーＢＯＨ（保土ケ谷化学社製）、オイルブルー＃６０３（オリエント化学工業社製）、オイルピンク＃３１２（オリエント化学工業社製）、オイルレッド５Ｂ（オリエント化学工業社製）、オイルスカーレット＃３０８（オリエント化学工業社製）、オイルレッドＯＧ（オリエント化学工業社製）、オイルレッドＲＲ（オリエント化学工業社製）、オイルグリーン＃５０２（オリエント化学工業社製）、スピロンレッドＢＥＨスペシャル（保土ケ谷化学社製）、ｍ−クレゾールパープル、クレゾールレッド、ローダミンＢ、ローダミン６Ｇ、スルホローダミンＢ、オーラミン、４−ｐ−ジエチルアミノフェニルイミノナフトキノン、２−カルボキシアニリノ−４−ｐ−ジエチルアミノフェニルイミノナフトキノン、２−カルボステアリルアミノ−４−ｐ−ジヒドロオキシエチルアミノ−フェニルイミノナフトキノン、１−フェニル−３−メチル−４−ｐ−ジエチルアミノフェニルイミノ−５−ピラゾロン、１−β−ナフチル−４−ｐ−ジエチルアミノフェニルイミノ−５−ピラゾロン等が挙げられる。
【０１８９】
また、酸で発色する化合物としてアリールアミン類の有機染料を用いることができる。この目的に適するアリールアミン類としては、第一級、第二級芳香族アミンのような単なるアリールアミンのほかにいわゆるロイコ色素も含まれ、これらの例としては次のようなものが挙げられる。
【０１９０】
ジフェニルアミン、ジベンジルアニリン、トリフェニルアミン、ジエチルアニリン、ジフェニル−ｐ−フェニレンジアミン、ｐ−トルイジン、４，４′−ビフェニルジアミン、ｏ−クロロアニリン、ｏ−ブロモアニリン、４−クロロ−ｏ−フェニレンジアミン、ｏ−ブロモ−Ｎ，Ｎ−ジメチルアニリン、１，２，３−トリフェニルグアニジン、ナフチルアミン、ジアミノジフェニルメタン、アニリン、２，５−ジクロロアニリン、Ｎ−メチルジフェニルアミン、ｏ−トルイジン、ｐ，ｐ′−テトラメチルジアミノジフェニルメタン、Ｎ，Ｎ−ジメチル−ｐ−フェニレンジアミン、１，２−ジアニリノエチレン、ｐ，ｐ′，ｐ″ヘキサメチルトリアミノトリフェニルメタン（ロイコクリスタルバイオレット）、ｐ，ｐ′−テトラメチルジアミノトリフェニルメタン、ｐ，ｐ′−テトラメチルジアミノジフェニルメチルイミン、ｐ，ｐ′，ｐ″−トリアミノ−ｏ−メチルトリフェニルメタン、ｐ，ｐ′，ｐ″−トリアミノトリフェニルカルビノール、ｐ，ｐ′−テトラメチルアミノジフェニル−４−アニリノナフチルメタン、ｐ，ｐ′，ｐ″−トリアミノフェニルメタン、ｐ，ｐ′，ｐ″−ヘキサプロピルトリアミノトリフェニルメタン等。
【０１９１】
本発明において、顕色剤としては、感熱記録体において電子受容体として使用される酸性物質がいずれも使用でき、例えば酸性白土カオリン、ゼオライト等の無機酸、芳香族カルボン酸、その無水物又はその金属塩類、有機スルホン酸、その他の有機酸、フェノール系化合物、該フェノール系化合物のメチロール化物、該フェノール系化合物の塩又は錯体等の有機系顕色剤などが挙げられ、なかでもフェノール系化合物のメチロール化物およびフェノール系化合物の塩（以下、特に断りのないかぎり錯塩も含む）が好ましい。
【０１９２】
これら顕色剤のうち、有機系顕色剤の具体例としては、フェノール、４−フェニルフェノール、４−ヒドロキシアセトフェノン、２，２′−ジヒドロキシジフェニル、２，２′−メチレンビス（４−クロロフェノール）、２，２′−メチレンビス（４−メチル−６−ｔ−ブチルフェノール）、４，４′−イソプロピリデンジフェノール（別名ビスフェノールＡ）、４，４′−イソプロピリデンビス（２−クロロフェノール）、４，４′−イソプロピリデンビス（２−メチルフェノール）、４，４′エチレンビス（２−メチルフェノール）、４，４′−チオビス（６−ｔ−ブチル−３−メチルフェノール）、１，１−ビス（４−ヒドロキシフェニル）−シクロヘキサン、２，２′−ビス（４−ヒドロキシフェニル）−ｎ−ヘプタン、４，４′−シクロヘキシリデンビス（２−イソプロピルフェノール）、４，４′−スルホニルジフェノール等のフェノール系化合物、該フェノール系化合物のメチロール化物、該フェノール系化合物の塩サリチル酸アニリド、ノボラック型フェノール樹脂、ｐ−ヒドロキシ安息香酸ベンジル等が挙げられる。
【０１９３】
本発明においては、顕色剤とともに用いられる発色剤としては、トリフェニルメタンラクトン型などのロイコ色素を用いることができる。
【０１９４】
このようなロイコ色素としては、例えば、クリスタルバイオレットラクトン、３−ジエチルアミノ−７−クロロフルオラン、３−ジエチルアミノ−６−メチル−７−クロロフルオラン、２−（Ｎ−フェニル−Ｎ−メチルアミノ）−６−（Ｎ−ｐ−トリル−Ｎ−エチル）アミノフルオラン、マラカイトグリーンラクトン、３，３−ビス（１−エチル−２−メチルドール−３−イル）フタリド、３−ジエチルアミノ−６−メチル−７−アニリノフルオラン、２−アニリノ−３−メチル−６−（Ｎ−エチル−ｐ−トルイジノ）フルオラン、３−（Ｎ−シクロヘキシル−Ｎ−メチルアミノ）−６−メチル−７−アニリノフルオラン、３−ピペリジノ−６−メチル−７−アニリノフルオランなどが挙げられる。
【０１９５】
上記発色剤と顕色剤は、顕色剤／発色剤の質量比が０．１／１〜５／１となる範囲で通常用いるが、なかでも該質量比が０．５／１〜３／１となる範囲が好ましい。
【０１９６】
〈画像形成機能層の反対側の構成層〉
本発明においては、取り扱い性及び保管時の物性変化防止のために、支持体の画像形成機能層の反対側に少なくとも１層の構成層を有することが好ましい。好ましい構成層としては、下引き層、親水性結合剤含有層または疎水性結合剤含有層であり、結合剤含有層は下引き層の上に塗設されてもよい。
【０１９７】
下引き層としては、前述の支持体の下引き層が好ましい。
親水性結合剤としては、親水性のものなら特に限定はされないが、親水性構造単位としてヒドロキシル基を有する樹脂であるポリビニルアルコール（ＰＶＡ）、セルロース系樹脂（メチルセルロース（ＭＣ）、エチルセルロース（ＥＣ）、ヒドロキシエチルセルロース（ＨＥＣ）、カルボキシメチルセルロース（ＣＭＣ）等）、キチン類、及びデンプン；エーテル結合を有する樹脂であるポリエチレンオキサイド（ＰＥＯ）、ポリプロピレンオキサイド（ＰＰＯ）、ポリエチレングリコール（ＰＥＧ）及びポリビニルエーテル（ＰＶＥ）；アミド基又はアミド結合を有する樹脂であるポリアクリルアミド（ＰＡＡＭ）及びポリビニルピロリドン（ＰＶＰ）等を挙げることができる。また、解離性基としてカルボキシル基を有するポリアクリル酸塩、マレイン酸樹脂、アルギン酸塩及びゼラチン類；スルホン基を有するポリスチレンスルホン酸塩；アミノ基、イミノ基、第３アミン及び第４級アンモニウム塩を有するポリアリルアミン（ＰＡＡ）、ポリエチレンイミン（ＰＥＩ）、エポキシ化ポリアミド（ＥＰＡｍ）、ポリビニルピリジン及びゼラチン類を挙げることができる。
【０１９８】
疎水性結合剤は、結合剤として疎水性のものなら特に限定されないが、例えばα，β−エチレン性不飽和化合物に由来するポリマー、例えばポリ塩化ビニル、後−塩素化ポリ塩化ビニル、塩化ビニルと塩化ビニリデンのコポリマー、塩化ビニルと酢酸ビニルのコポリマー、ポリ酢酸ビニル及び部分的に加水分解されたポリ酢酸ビニル、出発材料としてポリビニルアルコールから作られ、繰り返しビニルアルコール単位の一部のみがアルデヒドと反応していることができるポリビニルアセタール、好ましくはポリビニルブチラール、アクリロニトリルとアクリルアミドのコポリマー、ポリアクリル酸エステル、ポリメタクリル酸エステル、ポリスチレン及びポリエチレン又はそれらの混合物等が挙げられる。
【０１９９】
また疎水性結合剤は仕上がり印刷版材料表面が疎水性であれば、特開２００２−２５８４６９号公報の段落００３３〜００３８に記載されている水分散系樹脂（ポリマーラテックス）から得られたものでもよい。
【０２００】
また印刷機の版胴への取り付けやすさ、および、印刷中における印刷版の位置ずれによるカラー印刷での色ずれを防止するために、本発明において該構成層のうちの最表面層に平均粒径１μｍ以上２０μｍ未満のマット剤を含有させることが好ましい。
【０２０１】
好ましく用いられるマット剤としては新モース硬度５以上の無機微粒子や有機マット剤があげられる。新モース硬度５以上の無機微粒子としては、例えば金属酸化物粒子（シリカ、アルミナ、チタニア、ジルコニア、酸化鉄、酸化クロム等）や金属炭化物粒子（炭化珪素等）、窒化ホウ素粒子、ダイアモンド粒子等が挙げられる。有機マット剤としては、例えばＵＳＰ２，３２２，０３７号明細書等に記載の澱粉、ＢＥＰ６２５，４５１号やＧＢＰ９８１，１９８号明細書等に記載された澱粉誘導体、特公昭４４−３６４３号公報等に記載のポリビニルアルコール、ＣＨＰ３３０，１５８号明細書等に記載のポリスチレン或いはポリメタアクリレート、ＵＳＰ３，０７９，２５７号等明細書に記載のポリアクリロニトリル、ＵＳＰ３，０２２，１６９号明細書等に記載されたポリカーボネートがあげられる。
【０２０２】
これらマット剤の添加量は１ｍ^２あたり０．１ｇ以上１０ｇ未満であることが好ましい。
【０２０３】
本発明においては、前記のマット剤の粒径、添加量および結合剤の量を調整することで、画像形成層の反対側の表面の表面粗さは、Ｒａ値で、０．１μｍ以上２μｍ未満であることが好ましい。０．１μｍ未満では摩擦係数が高い等の理由で印刷版材料の搬送性に問題を生じる懸念があったり、印刷版材料の印刷機への取付に不具合を生じたり場合もある。また、２μｍ以上の粗い表面では、印刷版材料の製造時その他でロールに巻かれる際に反対面に形成された塗布層を傷つける懸念や、印刷版材料を版胴上に固定した際に、裏面側からの突き上げで印刷版材料表面が部分的に突出し、その部分に印圧が集中するために耐刷不良を生じる懸念もある。
【０２０４】
さらに、レーザー記録装置あるいはプロセスレス印刷機には、装置内部において印刷版の搬送を制御するためのセンサーを有しており、これらの制御を滞りなく行うために、本発明において、該構成層には、色素および顔料を含有させることが好ましい。色素及び顔料としては、前述の光熱変換素材に用いられる赤外吸収色素及び顔料が好ましく用いられる。また、更に、該構成層には公知の界面活性剤を含有させることができる。
【０２０５】
〈包装材料〉
上記のように製造された印刷版材料は、所望のサイズに断裁した後に、後述する露光を行うまで保管するためにロール状に巻かれて包装される。その際に長期の保管に耐えるためには、包装材料として、特開２０００−２０６６５３号報に記載の酸素透過度５０ｍｌ／ａｔｍ・ｍ^２・３０℃・ｄａｙ以下の包装材料で包装されることが好ましい。またもう一つの好ましい形態として、特開２０００−２０６６５３号報に記載の水分透過度１０ｇ／ａｔｍ・ｍ^２・２５℃・ｄａｙ以下の包装材料で包装されることが好ましい。
【０２０６】
〈印刷〉
前記のようにして画像形成がなされた印刷版材料は、現像処理を行うことなく印刷を行うことが好ましい。画像形成後の印刷版材料をそのまま印刷機の版胴に取り付けるか、あるいは印刷版材料を印刷機の版胴に取り付けた後に画像形成を行い、版胴を回転させながら水供給ローラーおよびまたはインキ供給ローラーを印刷版材料に接触させることで画像形成層の非画像部を除去することが可能である。
【０２０７】
本発明の印刷版材料における上記の画像形成層非画像部の除去工程は、ＰＳ版を使用した通常の印刷シークエンスで行うことができるため、いわゆる機上現像処理による作業時間の延長の必要がないため、コストダウンにも有効である。
【０２０８】
さらに、本発明の印刷方法において、画像形成後から、印刷機上で印刷版材料表面と水供給ローラーまたはインキ供給ローラーとが接触するまでに印刷版材料の表面を乾燥させる工程を有することが好ましい。本発明の印刷方法においては画像形成直後から画像強度が徐々に向上していくと考えられる。レーザーで一般的な外面ドラム方式（前述の方式）では、一般に露光開始から終了までに３分程度かかるため、露光終了時での露光開始部と終了部とでは画像強度が異なる懸念がある。乾燥工程を設けることで画像強度の差を問題ないレベルにまで縮めることができる。
【０２０９】
また本発明の印刷版材料を印刷する場合には、石油系の揮発性有機化合物を使用しないインキ、いわゆる環境対応インキを使用した場合に、本発明の効果が顕著に現れる。
【０２１０】
本発明に用いられる環境対応インキの具体例としては、大日本インキ化学工業社製の大豆油インキ・ナチュラリス１００、東洋インキ社製のＶＯＣゼロインキ・ＴＫハイエコーＳＯＹ１、東京インキ社製のプロセスインキ・ソルセイボなどがあげられる。
【０２１１】
【実施例】
以下、実施例により本発明を説明するが、本発明はこれらに限定されない。
【０２１２】
実施例１
《支持体の作製》：プラスチックフィルムの作製
（支持体１：ポリエチレンテレフタレート支持体）
テレフタル酸とエチレングリコールを用い、常法に従いＩＶ（固有粘度）＝０．６６（フェノール／テトラクロルエタン＝６／４（質量比）中２５℃で測定）のＰＥＴを得た。これをペレット化した後１３０℃で４時間乾燥し、３００℃で溶融後Ｔ型ダイから押し出し、５０℃の冷却ドラム上で急冷し熱固定後の平均膜厚が１９０μｍになるような厚みの未延伸フィルムを作製した。これを、前段延伸の延伸温度を１０２℃とし１．１倍に、後段延伸は１１０℃で２．６倍に縦延伸した。ついでテンターで１２０℃で１．８倍に横延伸した。この後、２４０℃で２０秒間熱固定後、これと同じ温度で横方向に４％緩和した。この後テンターのチャック部をスリットした後、両端にナーリング加工を行い、４０℃に冷却後８３．３Ｎ／ｍで巻き取った。このようにして得たポリエチレンテレフタレートフィルムの幅（製膜幅）は２．５ｍであった。得られた支持体の厚み分布は１２％であった。
【０２１３】
（支持体２：ポリエチレンテレフタレート支持体）
テレフタル酸とエチレングリコールを用い、常法に従いＩＶ（固有粘度）＝０．６６（フェノール／テトラクロルエタン＝６／４（質量比）中２５℃で測定）のＰＥＴを得た。これをペレット化した後１３０℃で４時間乾燥し、３００℃で溶融後Ｔ型ダイから押し出し、５０℃の冷却ドラム上で急冷し熱固定後の平均膜厚が１９０μｍになるような厚みの未延伸フィルムを作製した。これを、前段延伸を１０２℃で１．３倍に、後段延伸は１１０℃で２．６倍に縦延伸した。ついでテンターで１２０℃で４．５倍に横延伸した。この後、２４０℃で２０秒間熱固定後これと同じ温度で横方向に４％緩和した。この後テンターのチャック部をスリットした後、両端にナーリング加工を行い、４０℃に冷却後４７．０４Ｎ／ｍで巻き取った。このようにして得たポリエチレンテレフタレートフィルムの幅（製膜幅）は２．５ｍであった。得られた支持体の厚み分布は３％であった。
【０２１４】
（支持体３：ポリエチレンテレフタレート支持体）
テレフタル酸とエチレングリコールを用い、常法に従いＩＶ（固有粘度）＝０．６６（フェノール／テトラクロルエタン＝６／４（質量比）中２５℃で測定）のＰＥＴを得た。これをペレット化した後１３０℃で４時間乾燥し、３００℃で溶融後Ｔ型ダイから押し出し、５０℃の冷却ドラム上で急冷し熱固定後の平均膜厚が３５０μｍになるような厚みの未延伸フィルムを作製した。これを、延伸温度は前段延伸が１０２℃で１．５倍に、後段延伸は１１０℃で４．０倍に縦延伸した。ついでテンターで１２０℃で５．０倍に横延伸した。この後、２４０℃で２０秒間熱固定後これと同じ温度で横方向に４％緩和した。この後テンターのチャック部をスリットした後、両端にナーリング加工を行い、４０℃に冷却後８３．３Ｎ／ｍで巻き取った。このようにして得たポリエチレンテレフタレートフィルムの幅（製膜幅）は２．５ｍであった。
【０２１５】
《下引き済み支持体の作製》
上記で得られた支持体１、２および３の各々のフィルムの両面に、８Ｗ／ｍ^２・分のコロナ放電処理を施し、次いで、一方の面に下記下引き塗布液ａを乾燥膜厚０．８μｍになるように塗設後にコロナ放電処理（８Ｗ／ｍ^２・分）を行いながら下引き塗布液ｂを乾燥膜厚０．１μｍになるように塗布し、各々１８０℃、４分間乾燥させた（下引き面Ａ）。また、表５に記載のように、反対側の面に下記下引き塗布液ｃ−１、ｃ−２またはｃ−３を乾燥膜厚０．８μｍになるように塗設後にコロナ放電処理（８Ｗ／ｍ^２・分）を行いながら下引き塗布液ｄ−１、ｄ−２またはｄ−３を乾燥膜厚１．０μｍになるように塗布し、それぞれ１８０℃、４分間乾燥させた（下引き面Ｂ）。また、支持体２の下引き面Ｂ側の表面の表面粗さを測定したところＲａ値で０．８μｍであった。
【０２１６】
《下引き塗布液ａ》

《下引き塗布液ｂ》

【０２１７】
【化１】

【０２１８】
《下引き塗布液ｃ−１》

《下引き塗布液ｄ−１》

成分ｄ−１１；
スチレンスルホン酸ナトリウム／マレイン酸＝５０／５０の共重合体からなるアニオン性高分子化合物
成分ｄ−１２；
スチレン／グリシジルメタクリレート／ブチルアクリレート＝４０／４０／２０からなる３成分系共重合ラテックス
成分ｄ−１３；
スチレン／イソプレンスルホン酸ナトリウム＝８０／２０からなる高分子活性剤
【０２１９】
【化２】

【０２２０】
《下引き塗布液ｃ−２》

《下引き塗布液ｄ−２》

《下引き塗布液ｃ−３》

ついで、各々の下引き層表面に下記プラズマ処理条件でプラズマ処理を施した。
【０２２１】
《プラズマ処理条件》
バッチ式の大気圧プラズマ処理装置（イーシー化学（株）製、ＡＰ−Ｉ−Ｈ−３４０）を用いて、高周波出力が４．５ｋＷ、周波数が５ｋＨｚ、処理時間が５秒及びガス条件としてアルゴン、窒素及び水素の体積比をそれぞれ９０％及び５％で、プラズマ処理を行った。
【０２２２】
《熱処理条件》
１．２５ｍ幅にスリットした後の支持体に対し、張力２ｈＰａで１８０℃、１分間の低張力熱処理を実施した。
【０２２３】
《印刷版材料の作製》
《印刷版材料１０１〜１０４の作製》
親水性層を塗設する直前に、下引き済み支持体に対し、１００℃で３０秒間熱処理を加えて乾燥させ、防湿シートでカバーをして空気中の湿度が入らないようにした。支持体試料の一部をサンプリングして水分率測定をしたところ、支持体１は１．２％、支持体２は０．２％、支持体３は１．２％であった。カバーをしたものについてはシートを除去後、すぐに塗布を行った。
【０２２４】
それぞれ、前記下引き済み支持体１、支持体２および支持体３、各々のＡ面上に、表２に示す親水性層１用塗布液（調製方法は下記に示す）、表３に示す親水性層２用塗布液（調製方法は下記に示す）を、表５に示す組み合わせでワイヤーバーを用いてそれぞれ乾燥付量が２．５ｇ／ｍ^２、０．６ｇ／ｍ^２になるように塗布し、１２０℃で３分間乾燥したのちに６０℃で２４時間の加熱処理を施した。その後、表４に示す画像形成機能層塗布液を、それぞれ、ワイヤーバーを用いて乾燥付量が０．６ｇ／ｍ^２になるように塗布して５０℃で３分間乾燥したのちに、５０℃で７２時間のシーズニング処理を施した。このように印刷版材料１０１〜１０４を作製した。塗布後の２５℃、２５％ＲＨでの表面電気抵抗は、試料１０１と１０４は１０^１２Ωであり、試料１０２と１０３は１０^８Ωであった。
【０２２５】
《親水性層１用塗布液の調製》
表２に記載の各素材を、表２に記載の組成でホモジナイザを用いて十分に攪拌混合した後、濾過して親水性層１用塗布液を調製した。なお、各素材の詳細は、以下の通りであり、表中の数値は質量部を表す。
【０２２６】
【表２】

【０２２７】
《親水性層２用塗布液の調製》
表３に記載の各素材を、表３に記載の組成でホモジナイザを用いて十分に攪拌混合した後、濾過して親水性層２用塗布液を調製した。なお、各素材の詳細は、以下の通りであり、表中の数値は質量部を表す。
【０２２８】
【表３】

【０２２９】
（※１）アクリル樹脂ａ：下記の製造方法で作製。
撹拌装置、温度調節器、還流管を備えた反応装置に酢酸ｎ−ブチル６５部を仕込み１１０℃に加温し、以下のモノマー組成の混合物を３時間かけて滴下した。
メチルメタクリレート ６０部
ｉ−ブチルメタクリレート １５部
ｉ−ブチルアクリレート ７．５部
２−ヒドロキシエチルアクリレート １０部
２−ヒドロキシエチルメタクリレート ２．５部
アクリル酸 ５部
アゾビスイソブチロニトリル ２．５部
滴下後１時間保温し、アゾビスイソブチロニトリルを０．５部と酢酸ｎ−ブチル１０部との混合溶液を１時間かけて滴下し、ついで１時間保温した。その後Ｎ，Ｎ−ジメチルエタノールアミンで０．７当量中和し、脱イオン水を加え、樹脂濃度が３０質量％となるまで希釈し、水性アクリル樹脂ａを得た。得られた樹脂ａの水酸基価は５９、酸価は３９であった。
【０２３０】
《画像形成機能層塗布液の調製》
【０２３１】
【表４】

【０２３２】
【化３】

【０２３３】
上記で作製した印刷版材料を、７３ｃｍ幅で３２ｍの長さに切断して直径７．５ｃｍのボール紙でできたコアに巻き付けロール形状の試料を作製した。さらに試料をＡｌ_２Ｏ_３ＰＥＴ（１２μｍ）／Ｎｙ（１５μｍ）／ＣＰＰ（７０μｍ）の材料でできた１５０ｃｍ×２ｍの包装材料で巻き、端面をヒートシールして外気と遮断した。作製した包装された印刷版材料試料を、強制劣化条件として５０℃、８０％ＲＨで７日間加温した。
【０２３４】
なお包装材料について、Ａｌ_２Ｏ_３ＰＥＴはアルミナ蒸着ＰＥＴ（ポリエチレンテレフタレート）を、Ｎｙはナイロンを、ＣＰＰはキャスティングポリプロピレンを表す。又、包装材料の酸素透過度は１．７ｍｌ／ａｔｍ・ｍ^２・３０℃・ｄａｙ、水分透過度は１．８ｇ／ａｔｍ・ｍ^２・２５℃・ｄａｙであった。
【０２３５】
《スティフネスの測定》
２０ｃｍ×１０ｃｍにサンプルを切り出し、フィルムスティフネステスターＵＴ−２００ＧＲ（東洋精機（株）製）を用いて、サンプルを平坦な台に置き、長辺側の両端を台に沿って近づけて、両端各５ｃｍは台への固定しろとし、中央部１０ｃｍを台から１ｃｍ上方にたわませて、頂上部を針で押して３ｍｍ押し下げた時の荷重を評価した。
【０２３６】
《印刷版材料１０１〜１０４の評価》
（ａ）赤外線レーザー方式による画像形成
上記の試料を露光サイズに合わせて切断した後に図１〜３に示す構成の露光装置を用いて、露光ドラムに巻付け固定した。露光には、波長８３０ｎｍ、スポット径約１８μｍのレーザービームを用い、露光エネルギーを１００〜３５０ｍＪ／ｃｍ^２まで５０ｍＪ毎に段階的に露光エネルギーを変化させ、２４００ｄｐｉ（ｄｐｉとは、２．５４ｃｍ当たりのドット数を表す。）、１７５線で画像を形成し、印刷版試料を作製した。
【０２３７】
露光で使用した露光ドラムは直径２７０ｍｍ、幅８５０ｍｍであり、露光条件は、ドラムを１分間に８５０回転で、像面レーザーパワーを２７０ｍＷとした。
【０２３８】
（ｂ）上記で画像形成した印刷版試料１０１〜１０４について、下記の印刷方法により、印刷版としての諸特性を評価した。
【０２３９】
《印刷方法》
印刷装置として、三菱重工業社製のＤＡＩＹＡ１Ｆ−１を用いて、コート紙と、湿し水としてアストロマーク３（日研化学研究所製）の２質量％溶液、環境対応インキとして、東洋インキ社製のトーヨーキングハイエコーＳＯＹ１Ｍ紅を使用して印刷を行った。
【０２４０】
《初期インキ着肉性の評価》
印刷開始のシークエンスをＰＳ版の印刷シークエンスで行い、何枚目で非画線部のインキ汚れがなくなるかを評価した。枚数が少ないほどインキ着肉性が優れている。印刷後に版面を観察したところ、本発明に係る材料の非画像部は除去されていた。
【０２４１】
《寸法安定性の評価》
印刷前に版面に２５μｍ幅のキズを２カ所５０ｃｍ離してつけた。１００枚印刷後の印刷紙面と３０００枚印刷後の印刷紙面で２カ所のキズの距離がどのくらい変化したかで寸法変化（μｍ）を測定した。変化が少ないほど優れている。
【０２４２】
《耐刷性の評価》
３％網点画像の点が半分以上欠落する印刷枚数を求めた（印刷は３万枚まで行った）。印刷枚数の多いほど優れている。
【０２４３】
以上により得られた結果を表５に示す。
【０２４４】
【表５】

【０２４５】
実施例２
《印刷版材料の作製》
実施例１で作製した印刷版材料１０２と同様にして作製した印刷版材料の画像形成機能層の上に、さらに下記オーバーコート層をワイヤーバーを用いて乾燥付量が０．４ｇ／ｍ^２となるように塗布し、５０℃で３分間乾燥した。そしてさらに画像形成機能層側とは支持体の反対側に下記バック層をワイヤーバーを用いて乾燥付量が１．５ｇ／ｍ^２になるように塗布し、５０℃で２０分間乾燥して印刷版材料２０１を作製した。さらに５０℃で２４時間のシーズニング処理を施し、その後２３℃相対湿度２０％で２４時間調湿した。
【０２４６】
《オーバーコート層塗布液》
９８％加水分解されたポリ酢酸ビニル（重量平均分子量２０万） １５質量部
ヘキサメチレンジイソシアネート １質量部
マット剤（不定形シリカ、平均粒径２μｍ） ２質量部
水 ８２質量部
《バック層塗布液》
ポリアクリル酸（商品名：ジュリマーＡＣ−１０Ｈ、日本純薬、平均分子量２０
万 水溶性樹脂） １６質量部
カルボジイミド（架橋剤） ２質量部
マット剤（不定形シリカ、平均粒径３．５μｍ） ２質量部
水 ８０質量部
またバック層の表面の表面粗さを測定したところ、Ｒａ値で０．９μｍであった。
【０２４７】
実施例１と同様にして評価を行った。なお実施例２での耐刷性の評価は、ベタ部にかすれが出る印刷枚数を求めた（印刷は５万枚まで行った）。
【０２４８】
以上により得られた結果を表６に示す。
【０２４９】
【表６】

【０２５０】
実施例３
《印刷版材料の作製》
実施例１で作製した印刷版材料１０３に用いたものと同じ下引済み支持体のＡ面に下記の塗布液を塗布、加熱乾燥（１８０℃、３０秒）し、乾燥膜厚０．２ｇ／ｍ^２の中間層を形成した。
【０２５１】
《中間層塗布液１》
ポリエステル系ラテックス分散液（ＡＡ−６４、固形分３０質量％、日本ＮＳＣ
（株）製） ５ｇ
酸化錫−酸化アンチモン水分散物（平均粒径０．１μｍ １７質量％） １５ｇ
ポリオキシエチレンアルキルフェニルエーテル（エマルゲン９１１、１０質量％
水溶液、花王（株）製） ２．０ｇ
蒸留水 ８０ｇ
次いで、上記中間層上に、下記の塗布液を塗布し、加熱乾燥（１００℃、１０分）することにより、乾燥質量５ｇ／ｍ^２の親水性層を形成した。
【０２５２】
《親水性層塗布液》

〈ゾル−ゲル調製液の作製〉
下記組成の液を室温において、１時間熟成してゾル−ゲル調製液を作製した。
テトラエトキシシラン ８．５ｇ
メタノール １．８ｇ
水 １５．０ｇ
リン酸 ０．０１５ｇ
次いで、上記親水性層の上に、下記の感熱記録層塗布液を塗布、乾燥（１００℃、２分）することにより、乾燥塗布質量０．６ｇ／ｍ^２の感熱記録層を形成して、平版印刷版３０１を得た。
【０２５３】
《感熱記録層塗布液》
スルホン酸発生型高分子化合物（平均分子量約３万）Ｂ−１ １．０ｇ
赤外線吸収剤Ａ（下記構造） ０．２ｇ
ビクトリアピュアブルーＢＯＨの対イオンを１−ナフタレン−スルホン酸にした
染料 ０．０５ｇ
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（株）製） ０．０２ｇ
メチルエチルケトン １５ｇ
プロピレングリコールモノメチルエーテル ２ｇ
メチルアルコール ８ｇ
ジメチルホムアミド １ｇ
【０２５４】
【化４】

【０２５５】
得られた印刷版について実施例１と同様にして評価を行った。
以上により得られた結果を表７に示す。
【０２５６】
【表７】

【０２５７】
【発明の効果】
大型露光ドラムで露光しても、寸法のズレや、露光不足による初期のインキ着肉性劣化がない耐刷性の高いプラスチック支持体を有する印刷版材料が得られた。
【図面の簡単な説明】
【図１】印刷版材料を露光ドラムに巻きつけた状態を示す斜視図。
【図２】露光ドラムの基本的構成を示す断面図。
【図３】印刷版材料を露光部に繰り出すための繰出部と露光部を示す全体構成図。
【符号の説明】
１ 圧力ロール
２ 吸引孔
３ 印刷版材料
５ 露光ドラム
７ 繰り出し部
８ 光学的書込み手段
９ 筐体
１０ 減圧孔弁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing plate material having a plastic support, which forms an image by irradiating a laser beam on an exposure drum, an image recording method using the printing material, a printing plate manufacturing method, and a printing method using the printing plate. About.
[0002]
[Prior art]
With the digitization of print data, a computer-to-plate (CTP) technology that is inexpensive, easy to handle, and has the same printability as a PS plate is required.
[0003]
As a support for a printing plate material used for CTP, there are various types, but a printing plate technology using a plastic film support has been known so as to be convenient for handling and carrying the printing plate ( Patent Documents 1, 2, 3).
[0004]
When exposing a printing plate material having such a plastic support to a laser, there is an image forming apparatus having a drum type exposure apparatus.
[0005]
The size of printed materials has been increasing year by year (Patent Document 4), and printing plate materials having a side of 550 mm or more have appeared.
[0006]
Therefore, when exposing a printing plate material with a laser, a large-sized image forming apparatus having an exposure drum having a diameter of 250 mm or more has appeared.
[0007]
On the other hand, short delivery times are required in the industry, and for that purpose, it is necessary to reduce the time for forming images. When exposure is performed while rotating at a high speed in an image forming apparatus having the above-described large-sized exposure drum, the film is stretched or deformed and the dimensions are shifted.
[0008]
In recent years, in order to reduce the burden on the global environment, expectations for a so-called processless CTP printing plate that does not require a wet development process using a special agent have been increasing. One of the most prominent is infrared laser recording, in which a type in which a printing plate material having an image layer containing heat fusible fine particles or heat fusible fine particles is developed on a press is known (Patent Documents 5 and 6). ).
[0009]
When these printing plates are exposed while rotating at a high speed in the image forming apparatus having the large-sized exposure drum, the dimensions are shifted, and the initial ink deposition due to insufficient exposure is inferior. There was a problem.
[0010]
[Patent Document 1]
JP-A-4-261538
[0011]
[Patent Document 2]
JP-A-5-257287
[0012]
[Patent Document 3]
JP 2000-258899 A
[0013]
[Patent Document 4]
JP-A-11-254743
[0014]
[Patent Document 5]
JP-A-9-12387
[0015]
[Patent Document 6]
JP-A-9-123388
[0016]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a heat-meltable fine particle which has no dimensional deviation due to film elongation or deformation even when exposed by an image forming apparatus having a large exposure drum, and has no initial ink deposition deterioration due to insufficient exposure. Another object of the present invention is to provide a printing plate material having an image layer containing heat-fusible fine particles, an image recording method using the printing material, a method for producing a printing plate, and a printing method using the printing plate.
[0017]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following means.
[0018]
1. A printing plate material having an image forming functional layer on a plastic support, which is formed by irradiating a laser beam on the exposure drum with an image recording device having an exposure drum having a diameter of 250 mm or more to form an image. A printing plate material, characterized in that the stiffness (ST) at 23 ° C. and 48% RH is 30 g ≦ ST ≦ 120 g.
[0019]
2. 2. The printing plate material as described in 1 above, wherein the image forming functional layer contains heat fusible fine particles or heat fusible fine particles.
[0020]
3. 3. The printing plate material as described in 1 or 2, further comprising at least one hydrophilic layer between the plastic support and the image layer forming functional layer.
[0021]
4. The printing plate material as described in any one of the above items 1 to 3, wherein the plastic support has an average thickness in a range of 100 µm to 300 µm.
[0022]
5. 4. The printing plate material as described in 3 above, wherein at least one of the hydrophilic layers has a porous structure.
[0023]
6. The printing plate material as described in any one of the above items 1 to 5, wherein any one layer on the plastic support contains a light-to-heat conversion material.
[0024]
7. The printing plate material as described in any one of the above items 1 to 6, wherein the moisture content of the support is 0.5% by mass or less.
[0025]
8. The printing plate material according to any one of the above items 1 to 7, wherein the printing plate material is wound in a roll shape.
[0026]
9. A printing plate material wound into a roll having an image forming functional layer on a plastic support is fed, and the fed printing plate material is wound around an exposure drum having a diameter of 250 mm or more, and is held by close contact with a reduced pressure. The image recording method of irradiating a laser beam according to image data from a surface having a forming functional layer, converting the laser beam absorbed by the printing plate material into heat, and forming an image on the printing plate material by the converted heat, An image recording method, wherein a stiffness (ST) of a printing plate material at 23 ° C. and 48% RH is 30 g ≦ ST ≦ 120 g.
[0027]
10. 9. The printing plate material according to any one of 1 to 8, which is wound around an exposure drum having a diameter of 250 mm or more, held in close contact under reduced pressure, irradiated with a laser beam to form an image, and then subjected to wet development processing. A method for producing a printing plate, characterized by producing a printing plate without using the same.
[0028]
11. 9. The printing plate material according to any one of 1 to 8, which is wound around an exposure drum having a diameter of 250 mm or more, held in close contact under reduced pressure, irradiated with a laser beam to form an image, and is not subjected to wet development processing. Printing method for printing on a printing press.
[0029]
Hereinafter, the present invention will be described in detail.
The scanning exposure apparatus used for the printing plate material of the present invention will be described. The laser used for the exposure of the present invention is more specifically a laser that emits light in the infrared and / or near-infrared region, that is, a laser that emits light in the wavelength range of 700 to 1500 nm. Exposure is preferred. Although a gas laser may be used as the laser, it is particularly preferable to use a semiconductor laser that emits light in the near infrared region.
[0030]
As an apparatus suitable for the scanning exposure of the present invention, any apparatus can be used as long as it can form an image on the surface of a printing plate material in response to an image signal from a computer using the semiconductor laser. In the present invention, the printing plate material held on the surface of a cylindrical exposure drum that rotates about an axis as a rotating body is rotated by rotating the drum using one or more laser beams from outside the cylinder. A method of exposing the entire surface of the printing plate material by moving in a direction perpendicular to the circumferential direction (sub-scanning direction) while scanning in the circumferential direction (main scanning direction) is preferable. The present invention is characterized in that the diameter of the exposure drum at that time is 250 mm or more.
[0031]
The printing plate material of the present invention is a printing plate material having an image forming functional layer on a plastic support wound in a roll shape, and the fed printing plate material is wound around an exposure drum and held by pressure-contact. Exposure is performed by a device that irradiates a laser beam according to image data from the surface having the image forming functional layer.
[0032]
Preferably, thereafter, the laser beam absorbed by the printing plate material of the present invention is converted into heat, and the converted heat forms an image.
[0033]
(Explanation of device example)
An outline of an example of an apparatus for performing the method of the present invention will be described with reference to the drawings.
[0034]
1 to 3 are views showing an example of an apparatus, FIG. 1 is a perspective view showing a state in which a printing plate material is wound around an exposure drum, FIG. 2 is a sectional view showing a basic configuration of the exposure drum, and FIG. FIG. 2 is an overall configuration diagram showing a feeding section for feeding a material to an exposure section and an exposure section.
[0035]
The printing plate material fed to the exposure unit is wound into a roll, and the roll-shaped printing plate material is set in the feeding unit 7.
[0036]
The present invention is characterized in that the diameter of the exposure drum 5 is 250 mm or more, that is, a drum that can cope with an increase in size is used.
[0037]
The exposure drum 5 used in this example of the apparatus has a plurality of suction holes 2 so that the printing plate material is brought into close contact with the drum surface under reduced pressure. The pressure roll 1 is provided on the exposure drum 5 in order to improve the adhesion between the printing plate material and the drum. 3 is a printing plate material. Reference numeral 8 denotes an optical writing means by laser exposure, 9 denotes a housing, and 10 denotes a pressure reducing valve. When the suction hole at the end of the exposure drum is opened due to the printing plate material width, the pressure reducing valve is closed and adjusted so that the suction pressure does not drop.
[0038]
In the above-described apparatus example, the printing plate material is fed from the feeding section 7, cut into a predetermined length, wound around the exposure drum 5, and the sheet is held in a closely contacted state. Next, it is laser-exposed and discharged after exposure.
[0039]
<Stiffness (ST)>
In the present invention, the stiffness can be measured using a commercially available film stiffness tester (for example, “Stiffness Tester UT-100-230” or “Stiffness Tester UT-200GR” manufactured by Toyo Seiki Seisaku-sho, Ltd.). Specifically, the long side of a 20 cm x 10 cm sample placed on a flat table is brought close to the table, and both ends are fixed at 5 cm to the table, and the center is bent 1 cm above the table. Then, the top was pressed with a needle and evaluated by the load when pushed down by 3 mm.
[0040]
In the printing plate material, the stiffness range of the present invention can be achieved by appropriately selecting and combining a plurality of technical means described below.
[0041]
(1) As a support for a printing plate material, the elastic modulus (E120) at 120 ° C. is 1000 to 6000 N / mm.²Is used.
[0042]
(2) The average thickness of the support of the printing plate material is set to 100 to 300 μm.
(3) Adjust the stretching conditions in the production of the printing plate material support.
[0043]
(4) The water content of the support of the printing plate material is set to 0.5% by mass or less.
(5) At least one hydrophilic layer is disposed between the support of the printing plate material and the image forming functional layer, and the hydrophilic layer has a porous structure.
[0044]
(6) At least one hydrophilic layer is disposed between the support of the printing plate material and the image forming functional layer, and the dry solid content of the hydrophilic layer is 1 m.²0.5 g to 5 g per weight.
[0045]
(7) At least one layer containing a conductive compound is provided on at least one surface of the support.
[0046]
Hereinafter, each technical means will be described.
(1) As a support for a printing plate material, the elastic modulus (E120) at 120 ° C. is 1000 to 6000 N / mm.²It is preferable to use a plastic film support that is
[0047]
<Plastic film support>
(Constituent material of support)
As a constituent material of the plastic film support according to the present invention, a plastic film is preferable, and examples thereof include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, and cellulose esters.
[0048]
The support according to the present invention has an elastic modulus at 120 ° C. (E120) of 100 kg / mm from the viewpoint of imparting the above-described handling suitability to the printing plate material of the present invention.²~ 600kg / mm²And more preferably 120 kg / mm²~ 500kg / mm²It is. Specifically, polyethylene naphthalate (E120 = 410 kg / mm²), Polyethylene terephthalate (E120 = 150 kg / mm)²), Polybutylene naphthalate (E120 = 160 kg / mm)²), Polycarbonate (E120 = 170 kg / mm)²), Syndiotactic polystyrene (E120 = 220 kg / mm²), Polyetherimide (E120 = 190 kg / mm)²), Polyarylate (E120 = 170 kg / mm)²), Polysulfone (E120 = 180 kg / mm)²), Polyether sulfone (E120 = 170 kg / mm)²) And the like. These may be used alone, or may be used by laminating or mixing. Among them, particularly preferred plastic films include polyethylene naphthalate and polyethylene terephthalate.
[0049]
Here, the elastic modulus is obtained by using a tensile tester to find the slope of the stress with respect to the strain amount in a region where the strain indicated by the marked line of the sample conforming to JIS C2318 and the corresponding stress have a linear relationship. It is a thing. This is a value called a Young's modulus, and in the present invention, the Young's modulus is defined as an elastic modulus.
[0050]
(2) The average thickness of the support of the printing plate material is set to 100 to 300 μm.
Further, the support according to the present invention, in order for the printing plate material of the present invention to exhibit the effects described in the present invention, from the viewpoint of improving the handling suitability when installing the printing plate material in a printing press, the average film thickness. Is preferably in the range of 100 μm to 300 μm, and the thickness distribution is preferably 10% or less.
[0051]
As described above, the average thickness of the support is preferably in the range of 100 μm to 300 μm, more preferably in the range of 120 μm to 280 μm, and particularly preferably in the range of 150 μm to 260 μm.
[0052]
The thickness distribution (the value obtained by dividing the difference between the maximum value and the minimum value of the thickness by the average thickness and expressed as a percentage) of the support according to the present invention is preferably 10% or less as described above, and more preferably 8% or less. %, Particularly preferably 6% or less.
[0053]
Here, the method of measuring the thickness distribution of the support is as follows. A support cut out into a square having a side of 60 cm is drawn in a grid pattern at intervals of 10 cm in length and width, and the thickness of these 25 points is measured, and the average value and the maximum value are measured. Find the value and minimum value.
[0054]
(3) Adjust the stretching conditions in the production of the printing plate material support.
It is preferable to adjust the stretching conditions in the production of the support for the printing plate material so that the stiffness of the printing plate material falls within the range of the present invention.
[0055]
The stiffness increases as the stretching ratio increases, and decreases as the stretching ratio decreases. Although the stiffness changes in both the vertical and horizontal stretching ratios, the effect of the vertical stretching is particularly large. Also, when the stretching temperature is lowered, the orientation advances and becomes larger, and when it is raised, the orientation becomes smaller. Further, the degree of polymerization also affects the stiffness. As the degree of polymerization increases, the stiffness also increases.
[0056]
(Method of manufacturing support)
In order to adjust the average film thickness and the thickness distribution of the support according to the present invention to the above ranges, there is a method of adjusting the film forming conditions appropriately, or adjusting the film with a smooth roller while reheating after film formation. In the present invention, it is preferable to be manufactured by the film forming process described below.
[0057]
That is, as a means for forming a film of the support, a thermoplastic resin is melted at a temperature between melting point (Tm) and Tm + 50 ° C., filtered through a sintering filter or the like, extruded from a T-die, and subjected to a glass transition temperature (Tg). An unstretched sheet is formed on a casting drum adjusted to a temperature of −50 ° C. to Tg. At this time, in order to make the thickness distribution fall within the above range, it is preferable to use an electrostatic application method or the like.
[0058]
The unstretched sheet is longitudinally stretched 2 to 4 times between Tg and Tg + 50 ° C. Further, as another method for adjusting the thickness distribution to the above range, it is preferable to perform longitudinal stretching in multiple stages. At this time, it is preferable to adjust the temperature of the second-stage stretching higher than that of the first-stage stretching in the range of 1 ° C to 30 ° C, and more preferably, to adjust the temperature in the range of 2 ° C to 15 ° C.
[0059]
The magnification in the first-stage stretching is preferably 0.25 to 0.7 times, more preferably 0.3 to 0.5 times the magnification in the second-stage stretching. Then, after holding for 5 seconds to 60 seconds, more preferably for 10 seconds to 40 seconds in the temperature range of Tg-30 ° C. to Tg, it is increased 2.5 to 5 times between Tg and Tg + 50 ° C. in the lateral direction. Stretching is preferred.
[0060]
Thereafter, heat fixing is performed at (Tm-50 ° C.) to (Tm-5 ° C.) for 5 seconds to 120 seconds while being held by the chuck. At this time, it is also preferable to reduce the chuck interval by 0% to 10% in the width direction (thermal relaxation). After cooling, a method of attaching a knurling of 10 μm to 100 μm to the end (also referred to as providing a knurling height), winding, and obtaining a multiaxially stretched film is preferable.
[0061]
(Easy adhesion treatment to support, application of undercoat layer)
In the support according to the present invention, in order to improve the adhesiveness with the coating layer, it is preferable to apply an easy adhesion treatment or an undercoating layer to the coating surface. Examples of the easy adhesion treatment include a corona discharge treatment, a flame treatment, a plasma treatment, and an ultraviolet irradiation treatment.
[0062]
As the undercoat layer, it is preferable to provide a layer containing gelatin or latex described later on a support. It is also preferable to provide a conductive layer containing a conductive compound as described below as an undercoat layer.
[0063]
Further, as the support according to the present invention, a plastic film support is used, and a plastic film and a material such as a metal plate (for example, iron, stainless steel, aluminum, etc.) or paper coated with polyethylene (also referred to as a composite base material). ) Can be used as appropriate. These composite base materials may be bonded before forming a coating layer, may be bonded after forming a coating layer, or may be bonded immediately before being attached to a printing machine.
[0064]
(Fine particles)
Further, it is preferable to add fine particles of 0.01 μm to 10 μm to the above-mentioned support in an amount of 1 ppm to 1000 ppm for improving the handling property.
[0065]
Here, the fine particles may be either an organic substance or an inorganic substance. For example, as inorganic substances, silica described in Swiss Patent No. 330,158, etc., glass powder described in French Patent No. 1,296,995, etc., British Patent No. 1,173,181 Alkaline earth metals or carbonates such as cadmium, zinc, and the like described in publications and the like can be used. Examples of the organic substance include starch described in U.S. Pat. No. 2,322,037, starch derivatives described in Belgian Patent No. 625,451 and British Patent No. 981,198, and the like. No. 44-3643, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, etc., polyacrylonitrile described in U.S. Pat. No. 3,079,257, U.S. Pat. Organic fine particles such as polycarbonate described in Japanese Patent No. 3,022,169 can be used. The shape of the fine particles may be either regular or irregular.
[0066]
(4) The water content of the support of the printing plate material is set to 0.5% by mass or less.
In the present invention, the moisture content of the support is D 'represented by the following formula.
[0067]
D ′ (% by mass) = (w ′ / W ′) × 100
(Wherein W 'is the mass of the support in equilibrium with humidity in an atmosphere of 25 ° C. and 60% RH, w ′ is the moisture of the support in equilibrium with humidity in an atmosphere of 25 ° C. and 60% RH) Content is shown.)
The moisture content of the support is preferably 0.5% by mass or less, more preferably 0.01 to 0.5% by mass, and particularly preferably 0.01 to 0.3% by mass.
[0068]
As means for controlling the water content of the support to 0.5% by mass or less, (a) heat-treating the support at 100 ° C. or more immediately before applying the coating solution for the image forming functional layer and other layers; C) controlling the relative humidity in the step of applying the coating solution for the image forming functional layer and other layers, and (c) heat treating the support at 100 ° C. or higher before applying the coating solution for the image forming functional layer and other layers. Then, cover with a moisture-proof sheet, store and apply immediately after opening. These may be performed in combination of two or more.
[0069]
(Heat treatment)
In the present invention, it is preferable to heat-treat the plastic film after stretching and heat-setting in order to favorably transport the printing plate material in an exposure device or the like. The heat treatment according to the present invention is preferably achieved by the following means after cooling and winding after completion of heat setting and then unwinding in a separate step.
[0070]
As the heat treatment method according to the present invention, the film is transported by a transport method in which both ends of a film such as a tenter are gripped with pins or clips, a roll transport method using a plurality of roll groups, an air transport in which air is blown onto the film to float. A method of heat treatment using a method (a method of blowing heated air from a plurality of slits to one or both sides of a film surface), a method of using radiant heat from an infrared heater or the like, a method of contacting with a plurality of heated rolls, or a combination thereof. Further, it is preferable that the film hangs down by its own weight, and a conveying method such as winding is used below alone or in combination of a plurality of methods. The tension adjustment of the heat treatment can be achieved by adjusting the torque of the winding roll and / or the feeding roll, and / or by installing a dancer roll in the process and adjusting the load applied thereto. When the tension is changed during the heat treatment and / or at the time of cooling after the heat treatment, a desired tension state may be set by installing dancer rolls before and / or after these steps and / or adjusting their loads. . In addition, it is possible to effectively change the conveying tension by reducing the span between the heat treatment rolls.
[0071]
In the heat treatment according to the present invention, it is desirable to reduce the transfer tension as much as possible and to lengthen the heat treatment time in order to reduce the dimensional change during the subsequent heat treatment (thermal development) without hindering the progress of the heat shrinkage. The processing temperature is preferably in a temperature range of Tg + 50 to Tg + 150 ° C. of the plastic film, and in that temperature range, the transport tension is preferably 5 Pa to 1 MPa, more preferably 5 Pa to 500 kPa, and still more preferably 5 Pa to 200 kPa. Is preferably 30 seconds to 30 minutes, more preferably 30 seconds to 15 minutes. By setting the temperature range, the transport tension range, and the processing time to the above, the flatness of the support is not deteriorated due to a partial difference in thermal shrinkage of the support during the heat treatment, and fine scratches due to friction with the transport roll and the like. Etc. can be suppressed.
[0072]
In the present invention, the heat treatment is required at least once in order to obtain a desired purpose, and can be performed two or more times as necessary.
[0073]
In the present invention, the heat-treated plastic film is cooled from a temperature in the vicinity of Tg to room temperature and then wound up. In order to prevent deterioration in flatness due to cooling at this time, at least −5 is required until the temperature is lowered to room temperature over Tg. It is preferable to cool at a rate of at least ° C / sec.
[0074]
In the present invention, the heat treatment is preferably performed after the above-mentioned undercoat layer is applied. For example, it is preferable to apply an undercoat layer in-line between extrusion, heat fixation, and cooling, wind it up, and heat-treat it in another step. Further, after winding once after the heat setting, an undercoat may be applied and dried in another step, and then the heat treatment may be performed in a state where the undercoated plastic film support is continuously kept flat. Further, after applying and drying various functional layers such as a back layer, a conductive layer, a slippery layer, and an undercoat layer, the same heat treatment as described above may be performed.
[0075]
(5) At least one hydrophilic layer is disposed between the support of the printing plate material and the image forming functional layer, and the hydrophilic layer has a porous structure.
[0076]
(6) At least one hydrophilic layer is disposed between the support of the printing plate material and the image forming functional layer, and the hydrophilic layer has a dry solid content of 1 m.²0.5 g to 5 g per weight.
[0077]
<Hydrophilic layer>
The printing plate material of the present invention has an image forming function layer, and has a configuration having at least one hydrophilic layer between the support and the image forming function layer. The hydrophilic layer provided between the support and the image forming functional layer will be described. The hydrophilic layer is defined as a layer having low affinity for ink and high affinity for water when the printing plate material of the present invention is used as a printing plate. The hydrophilic layer will be described later.
[0078]
(7) At least one surface of the support has at least one layer containing a conductive compound.
[0079]
In the present invention, the conductive compound is a conductive polymer, metal oxide or conductive carbon black.
[0080]
The conductive polymer used in the present invention is preferably a water-soluble conductive polymer, and can have an antistatic function when used together with a hydrophobic polymer particle and a curing agent. Examples of the water-soluble conductive polymer include a polymer having at least one conductive group selected from sulfonic acid groups, sulfate groups, quaternary ammonium salts, tertiary ammonium salts, and carboxyl groups. The conductive group requires 5% by mass or more per polymer molecule. The water-soluble conductive polymer may contain a hydroxy group, an amino group, an epoxy group, an aziridine group, an active methylene group, a sulfinic acid group, an aldehyde group, and a vinyl sulfone group. The molecular weight of the polymer is preferably from 3,000 to 100,000, more preferably from 3,500 to 70,000. Specific examples of the water-soluble conductive polymer include compounds described in paragraphs (0033) to (0046) of JP-A-7-20596.
[0081]
These polymers can be synthesized by polymerizing a commercially available or conventional monomer. The addition amount of these compounds is 0.01 g / m²-10 g / m²And particularly preferably 0.1 g / m²~ 5g / m²It is. These compounds can be used alone or in combination with various hydrophilic binders or hydrophobic binders to form a layer. Gelatin or polyacrylamide are particularly advantageously used as hydrophilic binders, but others include colloidal albumin, cellulose acetate, cellulose nitrate, polyvinyl alcohol, hydrolyzed polyvinyl acetate, phthalated gelatin. Can be Examples of the hydrophobic binder include polymers having a molecular weight of 20,000 to 1,000,000 or more, styrene-butyl acrylate-acrylic acid terpolymer, butyl acrylate-acrylonitrile-acrylic acid terpolymer, methyl methacrylate-ethyl acrylate. -An acrylic acid terpolymer.
[0082]
Hydrophobic polymer particles that can be contained in the conductive layer are composed of so-called latex particles that are substantially insoluble in water, and this hydrophobic polymer is not particularly limited, and styrene, a styrene derivative, an alkyl acrylate, an alkyl methacrylate, an olefin derivative, It can be obtained by polymerizing a monomer selected in any combination from halogenated ethylene derivatives, vinylster derivatives, acrylonitrile and the like. In particular, it is preferable that at least 30 mol% of a styrene derivative, alkyl acrylate, or alkyl methacrylate is contained, and it is particularly preferable that the content is 50 mol% or more.
[0083]
There are two methods for converting a hydrophobic polymer into a latex by emulsion polymerization (emulsion polymerization method), dissolving a solid polymer in a low-boiling solvent, finely dispersing, and distilling off the solvent (dispersion method). Either of them can be employed, but it is preferable to carry out emulsion polymerization from the viewpoint that a fine and uniform particle size can be obtained. The molecular weight of the hydrophobic polymer may be 3000 or more, and there is almost no difference in transparency due to the molecular weight.
[0084]
Specific examples of the hydrophobic polymer include compounds described in paragraphs (0052) to (0057) of JP-A-7-20596. The addition amount of the hydrophobic polymer is preferably 0.01 g / m²-10 g / m²And particularly preferably 0.1 g / m²~ 5g / m²It is.
[0085]
As the activator used in the emulsion polymerization or the dispersant used in the dispersion method, a nonionic activator is used, and a polyalkylene oxide compound is preferably used. The polyalkylene oxide compound refers to a compound containing at least 3 or more and at most 500 or less polyalkylene oxide chains in a molecule, such as polyalkylene oxide and aliphatic alcohols, phenols, fatty acids, aliphatic mercaptans, and organic amines. It can be synthesized by a condensation reaction with a compound having an active hydrogen atom such as, or by condensing an aliphatic mercaptan, an organic amine, ethylene oxide, propylene oxide, or the like with a polyol such as polypropylene glycol or polyoxytetramethylene polymer. .
[0086]
The above polyalkylene oxide compound may be a block copolymer in which the polyalkylene oxide chain in the molecule is divided into two or more sites instead of one. At this time, the total polymerization degree of the polyalkylene oxide is preferably 3 or more and 100 or less. Specific examples of the polyalkylene oxide compound optionally used in the present invention include, for example, compounds described in the specification of Japanese Patent Application No. 2-65831.
[0087]
As a curing agent that can be used for the conductive layer, a hydroxy-containing epoxy curing agent is preferable, but a reaction product [CA] of polyglycidol and epihalohydrin is more preferable. This is considered to be a mixture in terms of the synthesis method.However, since the effect of the present invention can be obtained by suppressing the number of hydroxy groups and the number of epoxy groups, it is not important whether or not the mixture is a mixture. It may be an isolate or a mixture. Specific examples include the compounds described in paragraphs 0062 to 0073 of JP-A-7-20596.
[0088]
Next, a metal oxide as a conductive compound will be described. The preferred metal oxides are crystalline metal oxide particles, but those containing oxygen vacancies and those containing a small amount of heteroatoms that form donors for the metal oxide used are generally conductive. In particular, those containing a small amount of a hetero atom forming a donor for the latter metal oxide are particularly preferable because they do not give fog to the silver halide emulsion.
[0089]
Examples of metal oxidation include ZnO₂, TiO₂, SnO₂, Al₂O₃, In₂O₃, SiO₂, MgO, BaO, MoO₃, V₂O₅Or a composite oxide thereof is preferable, and in particular, ZnO₂, TiO₂, SnO₂Is preferred. As an example including a hetero atom, for example, addition of Sb or the like to SnO or₂For this, the addition of Nb, Ta, or the like is effective. The addition amount of these different atoms is preferably in the range of 0.01 to 30 mol%, and particularly preferably in the range of 0.1 to 10 mol%.
[0090]
The metal oxide particles used in the present invention have conductivity, and have a volume resistivity of 10%.⁷Ωcm or less, especially 10⁵It is preferably Ωcm or less. This oxide is described in JP-A-56-143431, JP-A-56-120519, and JP-A-58-62647.
[0091]
The metal oxide particles are used by being dispersed or dissolved in a binder. The binder that can be used is not particularly limited as long as it has a film forming ability.
[0092]
In order to reduce the resistance of the conductive layer by using the metal oxide more effectively, the volume content of the metal oxide in the conductive layer is preferably higher, but in order to have sufficient strength as a layer. Requires a binder of at least about 5%, so that the volume percentage of the metal oxide is preferably in the range of 5 to 95%.
[0093]
The amount of metal oxide used is 0.05 g / m²-10 g / m²And more preferably 0.01 g / m²~ 5g / m²It is. Thereby, an antistatic property is obtained.
[0094]
When conductive carbon black is thermally decomposed by passing acetylene gas into a preheated reaction furnace, acetylene black, oil produced by a continuous pyrolysis method or the like in which the furnace temperature rises and the decomposition reaction automatically proceeds thereafter A conductive carbon black, such as lamp black, which is incompletely burned with a flame that does not disturb the tar, resin, etc., and other high-structure furnace blacks, and can be used alone or in combination of two or more. Is preferably 100 μm or less, particularly preferably 0.01 to 2 μm. When the particle size is 100 μm or more, the coating material is soiled during the production of the material, or the carbon black cannot be uniformly contained without sufficient dispersion, so that the commercial value is lost.
[0095]
The conductive carbon black is black and has an effect of preventing halation.
In the present invention, the layer containing the conductive compound may be coated on any side as long as it is on the polyester film support, but is preferably coated on the opposite side of the image forming functional layer with respect to the support. Is preferred. By providing this conductive layer, the chargeability is improved, the adhesion of dust and the like is reduced, and the occurrence of white spot failure during printing is greatly reduced.
[0096]
The printing plate material in the invention has a layer capable of forming a printable image after exposure or exposure and development on a plastic support. Preferably, a lithographic printing plate using a silver salt diffusion transfer method as described in JP-A-4-261538, a thermal laser recording or a thermal head recording is disclosed in JP-A-8-507727 or JP-A-8-507727. Printing plate materials of the ablation type as described in JP-A-6-186750 and the on-press development type and the hot-melt transfer type as described in JP-A-9-12387. Among them, ablation type, heat fusion image layer on-machine development type, and heat fusion transfer type printing plate materials, which are so-called processless CTP printing plates that do not require a developer treatment with a special chemical, impose a burden on the global environment. Is preferred because it is reduced. More preferably, a printing plate material having an image forming functional layer containing heat fusible fine particles or heat fusible fine particles on a plastic film support is preferred.
[0097]
<Image forming functional layer>
The image forming functional layer according to the present invention contains heat fusible and / or heat fusible fine particles. Specifically, it is preferable that the following materials can be contained.
[0098]
(Heat-meltable fine particles)
The heat-meltable fine particles used in the present invention are fine particles formed of a material which is particularly low in viscosity when melted and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 ° C. to 120 ° C. and a melting point of 60 ° C. to 150 ° C., and more preferably a softening point of 40 ° C. to 100 ° C. and a melting point of 60 ° C. to 120 ° C. If the melting point is lower than 60 ° C., the storage stability is a problem, and if the melting point is higher than 150 ° C., the ink deposition sensitivity decreases.
[0099]
Examples of usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, and fatty acid wax. These have a molecular weight of about 800 to 10,000, and these waxes may be oxidized to facilitate emulsification, and polar groups such as a hydroxyl group, an ester group, a carboxyl group, an aldehyde group, and a peroxide group may be introduced. Furthermore, in order to lower the softening point or to improve workability, these waxes include, for example, stearoamide, linoleamide, laurylamide, myristeramide, hardened bovine fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, It is also possible to add coconut fatty acid amide or a methylolated product of these fatty acid amides, methylene bissteraloamide, ethylene bissteraloamide and the like. Further, a cumarone-indene resin, a rosin-modified phenol resin, a terpene-modified phenol resin, a xylene resin, a ketone resin, an acrylic resin, an ionomer, and a copolymer of these resins can also be used.
[0100]
Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. These materials have relatively low melting points and low melt viscosities, so that high-sensitivity image formation can be performed. Further, since these materials have lubricity, damage when a shear force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches and the like is improved.
[0101]
The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.05 to 3 μm. When the average particle diameter is smaller than 0.01 μm, when the coating liquid of the layer containing the heat-fusible fine particles is applied on a hydrophilic layer having a porous structure described later, the heat-fusible fine particles , Or into the gaps of fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause background contamination. When the average particle diameter of the heat-meltable fine particles is larger than 10 μm, the resolution is reduced.
[0102]
Further, the composition of the heat-fusible fine particles may be changed continuously between the inside and the surface layer, or may be covered with a different material. As a coating method, a known microcapsule forming method, a sol-gel method, or the like can be used.
[0103]
The content of the heat-fusible fine particles in the constituent layer is preferably from 1 to 90% by mass, more preferably from 5 to 80% by mass of the whole layer.
[0104]
(Heat-fusible fine particles)
Examples of the heat-fusible fine particles according to the present invention include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the thermoplastic hydrophobic high polymer fine particles. The temperature is preferably lower than the decomposition temperature of the polymer fine particles. Further, the weight average molecular weight (Mw) of the high molecular polymer is preferably in the range of 10,000 to 1,000,000.
[0105]
Specific examples of the polymer constituting the polymer particles include, for example, polypropylene, polybutadiene, polyisoprene, diene (co) polymers such as ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( (N-methylolacrylamide) copolymer, (meth) acrylates such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyls such as polymers Ester (co) polymer, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof. Of these, (meth) acrylic acid esters, (meth) acrylic acid (co) polymers, vinyl ester (co) polymers, polystyrene, and synthetic rubbers are preferably used.
[0106]
The polymer particles may be composed of a polymer polymerized by any known method such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a gas phase polymerization method. As a method of forming fine particles of a polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of a high molecular polymer in an inert gas, drying and forming fine particles, A method in which a polymer is dissolved in an organic solvent immiscible with water, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled off to form fine particles. Further, the heat-fusible fine particles and the heat-fusible fine particles may be used in any method as a dispersant or a stabilizer during polymerization or micronization, if necessary, for example, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene. A surfactant such as glycol or a water-soluble resin such as polyvinyl alcohol may be used. Further, triethylamine, triethanolamine and the like may be contained.
[0107]
Further, the thermoplastic fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle diameter is smaller than 0.01 μm, and when the coating liquid of the layer containing the heat-fusible fine particles is applied on a porous hydrophilic layer described later, the heat-fusible fine particles are converted into the hydrophilic layer. , Or into the gaps of fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause background contamination. When the average particle diameter of the heat-fusible fine particles is larger than 10 μm, the resolution is reduced.
[0108]
Further, the composition of the thermoplastic fine particles may be such that the composition of the inside and the surface layer is continuously changed, or may be covered with a different material. As a coating method, a known microcapsule forming method, a sol-gel method, or the like can be used.
[0109]
The content of the thermoplastic fine particles in the constituent layer is preferably from 1 to 90% by mass, more preferably from 5 to 80% by mass of the whole layer.
[0110]
It is also a preferred embodiment that the image forming functional layer according to the present invention contains a light-to-heat conversion material described later.
[0111]
The dry coating weight of the image forming functional layer is preferably 0.10 to 1.50 g / m.², More preferably 0.15 to 1.00 g / m²It is.
[0112]
(Water-soluble material)
The image forming functional layer containing the heat-fusible and / or heat-fusible fine particles according to the present invention preferably further contains a water-soluble material. By containing a water-soluble material, when the image-forming functional layer in the unexposed area is removed using a fountain solution or ink on a printing press, the removability can be improved.
[0113]
As the water-soluble material, it is preferable to use the water-soluble resins and saccharides listed as materials that can be contained in the hydrophilic layer. As the water-soluble resin, a polysaccharide or sodium polyacrylate is preferable. These will be described later. It is preferable to use an oligosaccharide as the saccharide. Since the oligosaccharides dissolve in water quickly, the removal of the unexposed areas of the image forming functional layer on the printing device becomes very quick, and the printing operation of the normal PS plate is performed without being conscious of any special removal operation. It can be removed by printing with the same operation as that described above, and there is no increase in waste of printing. In addition, the oligosaccharide has no fear of lowering the hydrophilicity of the hydrophilic layer, and can maintain good printability of the hydrophilic layer. Oligosaccharides are generally sweet, crystalline substances that are soluble in water and are obtained by dehydrating and condensing several monosaccharides through glycosidic bonds. Oligosaccharides are a kind of o-glycoside using sugar as aglycone, so they are easily hydrolyzed with acids to produce monosaccharides, and depending on the number of monosaccharide molecules produced, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, etc. are categorized. The oligosaccharide in the present invention refers to a disaccharide to a decasaccharide.
[0114]
These oligosaccharides are roughly classified into reducing oligosaccharides and non-reducing oligosaccharides according to the presence or absence of a reducing group. Homo-oligosaccharides composed of a single monosaccharide and two or more monosaccharides Hetero-oligosaccharides are also classified. Oligosaccharides occur naturally in free or glycoside form and can also be obtained by partial hydrolysis of polysaccharides with acids or enzymes. In addition, various oligosaccharides are produced by glycosyl transfer by enzymes.
[0115]
Oligosaccharides often exist as hydrates in ordinary atmospheres. In addition, the melting points of hydrates and anhydrides are different, and examples are as shown in Table 1.
[0116]
[Table 1]

[0117]
In the present invention, it is preferable to apply and form a layer containing saccharides with an aqueous solution. The melting point is considered to be the hydrate melting point. As described above, because of having a relatively low melting point, the oligosaccharide is also melted in a temperature range in which the hot-melted fine particles are melted or a temperature range in which the hot-melted fine particles are fused, and the porous structure of the hot-melted fine particles is reduced It does not hinder image formation such as melt infiltration into the hydrophilic layer and fusion of the heat-fused fine particles.
[0118]
Among the oligosaccharides, trehalose, which is in a relatively high purity state, is available at low cost industrially and has a very low hygroscopicity despite its high solubility in water. Both sexes are very good.
[0119]
Also, when the oligosaccharide hydrate is heat-melted to remove the water of hydration and solidified (for a short time after solidification), it forms anhydrous crystals, but trehalose has a higher melting point than the hydrate. It is characteristic that the temperature is higher than 100 ° C. This means that immediately after re-coagulation, the exposed portion has a high melting point and is hardly melted, which has the effect of making it difficult to cause image defects such as banding at the time of exposure. To achieve the object of the present invention, trehalose is particularly preferred among the oligosaccharides.
[0120]
The content of the oligosaccharide in the constituent layer is preferably from 1 to 90% by mass, more preferably from 10 to 80% by mass of the whole layer.
[0121]
Further, the image forming functional layer according to the present invention preferably contains a light-to-heat conversion material described later.
[0122]
The dry coating weight of the image forming functional layer is preferably 0.10 to 0.75 g / m.², More preferably 0.15 to 0.50 g / m²It is.
[0123]
<Hydrophilic overcoat layer>
In the present invention, it is preferable to have a hydrophilic overcoat layer on the image forming functional layer in order to prevent damage during handling. The hydrophilic overcoat layer may be a layer immediately above the image forming function layer, or an intermediate layer may be provided between the image forming function layer and the hydrophilic overcoat layer. Preferably, the hydrophilic overcoat layer is removable on a printing press.
[0124]
In the present invention, the hydrophilic overcoat layer preferably contains a water-soluble resin or a water-swellable resin obtained by partially cross-linking the water-soluble resin. As the water-soluble resin, those contained in the image forming functional layer are used.
[0125]
In the present invention, the hydrophilic overcoat layer can contain a light-to-heat conversion material described below.
[0126]
In addition, in order to prevent the printing plate of the present invention from being damaged when the printing plate of the present invention is mounted on a laser recording apparatus or a printing machine, it is preferable in the present invention that the overcoat layer contains a matting agent having an average particle size of 1 μm or more and less than 20 μm.
[0127]
Preferred examples of the matting agent include inorganic fine particles having a new Mohs hardness of 5 or more and organic matting agents. Examples of the inorganic fine particles having a new Mohs hardness of 5 or more include metal oxide particles (silica, alumina, titania, zirconia, iron oxide, chromium oxide, and the like), metal carbide particles (silicon carbide, and the like), boron nitride particles, and diamond particles. No. Examples of the organic matting agent include starch described in U.S. Pat. No. 2,322,037, starch derivatives described in BE 625,451 and GB 981,198, etc., and JP-B-44-3643. Etc., polystyrene or polymethacrylate described in CH330,158, etc., polyacrylonitrile described in U.S. Pat. No. 3,079,257, U.S. Pat. No. 3,022,169. Examples thereof include polycarbonates described in the specification and the like.
[0128]
The added amount of these matting agents is 1 m²It is preferably 0.1 g or more and less than 10 g.
[0129]
In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution application for the purpose of ensuring uniformity of application. Specific examples of such a nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl ether, and the like. . The proportion of the nonionic surfactant in the total solid content of the overcoat layer is preferably 0.05 to 5% by mass, and more preferably 1 to 3% by mass.
[0130]
In the present invention, the dry coating amount of the overcoat layer is 0.05 to 1.5 g / m²Is more preferable, and a more preferable range is 0.1 to 0.7 g / m.²It is. Within this range, good stain prevention, scratch prevention, fingerprint mark adhesion prevention, and ablation scum generation can be achieved without impairing the removability of the overcoat layer on the printing press.
[0131]
<Hydrophilic layer>
The printing plate material of the present invention has an image forming function layer, and has a configuration having at least one hydrophilic layer between the support and the image forming function layer. The hydrophilic layer provided between the support and the image forming functional layer will be described. The hydrophilic layer is defined as a layer having low affinity for ink and high affinity for water when the printing plate material of the present invention is used as a printing plate.
[0132]
As described in claim 4, in the printing plate material of the present invention, it is preferable that at least one of the hydrophilic layers provided on the support has a porous structure. In order to form the hydrophilic layer having the porous structure, the following materials for forming a hydrophilic matrix are preferably used.
[0133]
(Metal oxide)
As a material forming the hydrophilic matrix, a metal oxide is preferable. The metal oxide preferably contains metal oxide fine particles, and examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle diameter is preferably in the range of 3 to 100 nm, and several kinds of metal oxide particles having different average particle diameters are used. Substance fine particles can also be used in combination. Further, the surface of the particles may be subjected to a surface treatment.
[0134]
The metal oxide fine particles can be used as a binder by utilizing the film forming property. Compared to the use of an organic binder, the decrease in hydrophilicity is less, so that it is suitable for use in a hydrophilic layer.
[0135]
(Colloidal silica)
Among them, colloidal silica can be particularly preferably used. Colloidal silica has the advantage of high film-forming properties even under relatively low-temperature drying conditions, and can provide good strength. The colloidal silica preferably includes a necklace-shaped colloidal silica described below, and fine-particle colloidal silica having an average particle size of 20 nm or less. Further, the colloidal silica preferably exhibits alkalinity as a colloid solution.
[0136]
Necklace-shaped colloidal silica is a general term for an aqueous dispersion of spherical silica having a primary particle diameter of the order of nm, and a spherical colloidal silica having a primary particle diameter of 10 to 50 nm is bonded to a length of 50 to 400 nm. Pearl necklace-shaped "colloidal silica.
[0137]
The pearl necklace shape (that is, pearl necklace shape) means that an image in which colloidal silica silica particles are connected and connected has a shape like a pearl necklace.
[0138]
The bonding between the silica particles constituting the necklace-shaped colloidal silica is presumed to be -Si-O-Si- in which -SiOH groups present on the surface of the silica particles are dehydrated and bonded. Specific examples of the necklace-shaped colloidal silica include the “Snowtex-PS” series manufactured by Nissan Chemical Industries, and the product name is “Snowtex-PS-S (the average particle diameter of "About 110 nm)", "Snowtex-PS-M (average particle diameter in a connected state is about 120 nm)" and "Snowtex-PS-L (average particle diameter in a connected state is about 170 nm)". The corresponding acidic products are "Snowtex-PS-SO", "Snowtex-PS-MO" and "Snowtex-PS-LO".
[0139]
By adding necklace-shaped colloidal silica, the strength can be maintained while ensuring the porosity of the layer, and it can be preferably used as a porous material for the hydrophilic layer matrix. Among these, when "Snowtex PS-S", "Snowtex PS-M", and "Snowtex PS-L", which are alkaline, are used, the strength of the hydrophilic layer is improved, and the number of printed sheets is large. However, the occurrence of background dirt is suppressed, which is particularly preferable.
[0140]
It is known that colloidal silica has a stronger bonding force as the particle diameter is smaller. In the present invention, it is preferable to use colloidal silica having an average particle diameter of 20 nm or less, more preferably 3 to 15 nm. Things.
[0141]
As described above, among the colloidal silicas, alkaline ones are particularly preferable because they have a high effect of suppressing the occurrence of background fouling. Examples of the alkaline colloidal silica having an average particle diameter in this range include “Snowtex-20 (particle diameter 10 to 20 nm)” and “Snowtex-30 (particle diameter 10 to 20 nm)” manufactured by Nissan Chemical Industries, Ltd. "Snowtex-40 (particle size 10-20 nm)", "Snowtex-N (particle size 10-20 nm)", "Snowtex-S (particle size 8-11 nm)", "Snowtex-XS (particle size) 4 to 6 nm) ".
[0142]
The colloidal silica having an average particle diameter of 20 nm or less is particularly preferable because it can further improve the strength while maintaining the porosity of the layer to be formed by being used in combination with the necklace-shaped colloidal silica described above.
[0143]
The ratio of colloidal silica having an average particle size of 20 nm or less to colloidal silica / necklace-like colloidal silica is preferably in the range of 95/5 to 5/95, more preferably in the range of 70/30 to 20/80, and more preferably 60/40. The range of ３０30/70 is more preferred.
[0144]
(Porous metal oxide particles)
In the present invention, porous metal oxide particles having a particle size of less than 1 μm can be contained as a porous material having a hydrophilic layer matrix structure. As the porous metal oxide particles, porous silica, porous aluminosilicate particles, or zeolite particles described below can be preferably used.
[0145]
(Porous silica, porous silica, porous aluminosilicate particles)
The porous silica particles are generally produced by a wet method or a dry method. In the wet method, a gel obtained by neutralizing an aqueous silicate solution can be dried and pulverized, or can be obtained by pulverizing a precipitate precipitated by neutralization. In the dry method, it is obtained by burning silicon tetrachloride together with hydrogen and oxygen to precipitate silica. The porosity and particle size of these particles can be controlled by adjusting the production conditions. As the porous silica particles, those obtained from a gel obtained by a wet method are particularly preferable.
[0146]
The porous aluminosilicate particles are produced, for example, by a method described in JP-A-10-71764. That is, it is an amorphous composite particle synthesized by a hydrolysis method using aluminum alkoxide and silicon alkoxide as main components. The particles can be synthesized in a ratio of alumina to silica of 1: 4 to 4: 1. Further, those produced as composite particles of three or more components by adding an alkoxide of another metal during the production can also be used in the present invention. The porosity and particle size of these composite particles can also be controlled by adjusting the production conditions.
[0147]
The porosity of the particles is preferably 0.5 ml / g or more in pore volume, more preferably 0.8 ml / g or more, and further preferably 1.0 to 2.5 ml / g. preferable. The pore volume is closely related to the water retention of the coating film, and the larger the pore volume, the better the water retention, the less the stain during printing, and the larger the water volume latitude. If the particle size increases, the particles themselves become very brittle, and the durability of the coating film decreases. Conversely, if the pore volume is less than 0.5 ml / g, the printing performance may be slightly insufficient.
[0148]
(Method of measuring pore volume)
Here, it is assumed that the above pore volume is measured using Autosorb-1 (manufactured by Cantachrome Co., Ltd.) and that the voids of the powder are filled with nitrogen by nitrogen adsorption measurement using a constant volume method. Is calculated from the nitrogen adsorption amount at a relative pressure of 0.998.
[0149]
(Zeolite particles)
Zeolite is a crystalline aluminosilicate and is a porous body having pores of a regular three-dimensional network structure having a pore diameter of 0.3 nm to 1 nm. The general formula combining natural and synthetic zeolites is as follows:
[0150]
(M₁, (M₂)_0.5)_m(Al_mSi_nO₂)_{(M + n)}・ XH₂O
Where M₁, M₂Is an exchangeable cation and M₁Is Li⁺, Na⁺, K⁺, Tl⁺, Me₄N⁺(TMA), Et₄N⁺(TEA), Pr₄N⁺(TPA), C₇H_FifteenN²⁺, C₈H₁₆N⁺And M₂Is Ca²⁺, Mg²⁺, Ba²⁺, Sr²⁺, C₈H₁₈N₂ ²⁺And so on. Further, n ≧ m, and the value of m / n, that is, the Al / Si ratio is 1 or less. The higher the Al / Si ratio, the greater the amount of exchangeable cations included, and thus the higher the polarity and, therefore, the higher the hydrophilicity. The preferred Al / Si ratio is 0.4 to 1.0, more preferably 0.8 to 1.0. x represents an integer.
[0151]
The zeolite particles used in the present invention are preferably synthetic zeolites having a stable Al / Si ratio and a relatively sharp particle size distribution. For example, zeolite A: Na₁₂(Al₁₂Si₁₂O₄₈) ・ 27H₂O: Al / Si ratio 1.0, zeolite X: Na₈₆(Al₈₆Si₁₀₆O₃₈₄) ・ 264H₂O: Al / Si ratio 0.811, zeolite Y: Na₅₆(Al₅₆Si₁₃₆O₃₈₄) ・ 250H₂O; an Al / Si ratio of 0.412;
[0152]
By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is also greatly improved, and it is difficult to stain during printing, and the water flow latitude is widened. In addition, stains on fingerprint traces are greatly reduced. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance is reduced.
[0153]
In addition, the hydrophilic layer matrix structure constituting the hydrophilic layer can contain layered clay mineral particles. Examples of the layered mineral particles include clay minerals such as kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, savonite, etc.), vermiculite, mica (mica), chlorite, hydrotalcite, and layered polysilicate. Salts (kanemite, macatite, aialite, magadiite, kenyaite, etc.) and the like. In particular, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The preferred charge density is 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density of 0.25 to 0.6; negative charge), vermiculite (charge density of 0.6 to 0.9; negative charge), and the like. In particular, synthetic fluorine mica is preferable because it can be obtained in a stable quality such as a particle size. Further, among synthetic fluorine mica, swellable ones are preferable, and those that are free swelling are more preferable.
[0154]
In addition, the above layered mineral intercalation compounds (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, complexing treatment with organic binder, etc.) are also used. can do.
[0155]
As for the size of the tabular layered mineral particles, the average particle size (the maximum length of the particles) is less than 1 μm when contained in the layer (including the case of passing through the swelling step and the dispersion peeling step). The aspect ratio is preferably 50 or more. When the particle size is in the above range, continuity and flexibility in the planar direction, which are characteristics of the thin layered particles, are imparted to the coating film, and a crack is unlikely to be formed, and a tough coating film in a dry state can be obtained. Further, in a coating liquid containing a large amount of particles, sedimentation of the particles can be suppressed by the thickening effect of the layered clay mineral. If the particle size is larger than the above range, the coating film may be uneven and the strength may be locally reduced. When the aspect ratio is less than the above range, the number of tabular grains with respect to the added amount is small, the viscosity is insufficient, and the effect of suppressing the sedimentation of the grains is reduced.
[0156]
The content of the layered mineral particles is preferably from 0.1 to 30% by mass of the entire layer, more preferably from 1 to 10% by mass. In particular, swellable synthetic fluorine mica and smectite are preferable because the effect can be seen even in a small amount. The layered mineral particles may be added as a powder to the coating solution. However, in order to obtain a good degree of dispersion by a simple liquid preparation method (which does not require a dispersing step such as media dispersion), the layered mineral particles are used alone. After preparing a gel swollen in water with the above, it is preferable to add the gel to a coating solution.
[0157]
A silicate aqueous solution can also be used as another additive material in the hydrophilic layer matrix constituting the hydrophilic layer. Alkali metal silicates such as sodium silicate, K silicate and Li silicate are preferred,₂/ M₂It is preferable to select the O ratio so that the pH of the entire coating solution when the silicate is added does not exceed 13, from the viewpoint of preventing the dissolution of the inorganic particles.
[0158]
Further, an inorganic polymer or an organic-inorganic hybrid polymer using a metal alkoxide by a so-called sol-gel method can also be used. The formation of the inorganic polymer or the organic-inorganic hybrid polymer by the sol-gel method is described, for example, in “Application of the Sol-Gel Method” (written by Mio Sakuhana / published by Agne Shofusha) or described in this document. Known methods described in the cited documents can be used.
[0159]
Further, in the present invention, a water-soluble resin may be contained. Examples of the water-soluble resin include polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymer, and conjugated diene-based polymer latex of methyl methacrylate-butadiene copolymer. Acrylic polymer latex, vinyl polymer latex, sodium polyacrylate, polyacrylamide, resins such as polyvinylpyrrolidone, and the like, the water-soluble resin used in the present invention, polysaccharides or sodium polyacrylate, It is preferable to use
[0160]
As the polysaccharides, starches, celluloses, polyuronic acid, pullulan and the like can be used.Methyl cellulose salts, carboxymethyl cellulose salts, cellulose derivatives such as hydroxyethyl cellulose salts are preferred, and sodium salts and ammonium salts of carboxymethyl cellulose. More preferred. This is because the effect of forming the surface shape of the hydrophilic layer in a favorable state can be obtained by including the polysaccharide in the hydrophilic layer.
[0161]
It is preferable that the surface of the hydrophilic layer has an uneven structure having a pitch of 0.1 to 20 μm like the aluminum grain of the PS plate, and the unevenness improves the water retention and the retention of the image area. Such a concavo-convex structure can be formed by adding an appropriate amount of a filler having an appropriate particle size to the hydrophilic layer matrix. However, the above-mentioned alkaline colloidal silica and the above-mentioned aqueous solution are added to the hydrophilic layer coating solution. When a hydrophilic layer is applied and dried by applying a hydrophilic layer, it is preferable to form the layer by causing phase separation, since a structure having better printability can be obtained.
[0162]
The form of the concavo-convex structure (such as pitch and surface roughness) depends on the type and amount of alkaline colloidal silica, the type and amount of water-soluble polysaccharide, the type and amount of other additives, the solid content concentration of the coating solution, and the wetness. It can be appropriately controlled by the film thickness, drying conditions and the like.
[0163]
In the present invention, the water-soluble resin added to the hydrophilic matrix structure preferably exists at least partially in a water-soluble state while being soluble in water. This is because, even when a water-soluble material is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity is reduced and printability may be deteriorated. Further, the resin may further contain a cationic resin. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine and derivatives thereof, tertiary amino groups and quaternary ammonium groups. Acrylic resin, diacrylamine and the like. The cationic resin may be added in the form of fine particles, for example, a cationic microgel described in JP-A-6-161101.
[0164]
In addition, the coating liquid used for coating the hydrophilic layer according to the present invention can contain a water-soluble surfactant for the purpose of improving coatability, such as a Si-based or F-based surfactant. Although a surfactant can be used, it is particularly preferable to use a surfactant containing a Si element, since there is no fear of causing printing stains. The content of the surfactant is preferably from 0.01 to 3% by mass, more preferably from 0.03 to 1% by mass of the entire hydrophilic layer (solid content as a coating solution).
[0165]
Further, the hydrophilic layer may contain a phosphate. In the present invention, since the coating solution for the hydrophilic layer is preferably alkaline, it is preferable to add phosphate as trisodium phosphate or disodium hydrogenphosphate. By adding the phosphate, an effect of improving the mesh opening at the time of printing can be obtained. The amount of the phosphate added is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass, as an effective amount excluding the hydrate.
[0166]
Further, a light-to-heat conversion material described below can be contained. In the present invention, the hydrophilic layer is disposed between the support and the image forming functional layer, and the hydrophilic layer has a dry solid content of 1 m.²It is preferably 0.5 to 5 g per unit. The hydrophilic layer may be a single layer or a plurality of layers, and in the case of a plurality of layers, the total amount of solid content of each layer falls within the above range.
[0167]
<Light-to-heat conversion material>
The image forming functional layer, the hydrophilic layer, the hydrophilic overcoat layer, and other layers provided in the invention preferably contain a photothermal conversion material.
[0168]
As the light-to-heat conversion material, an infrared absorbing dye or pigment can be added.
(Infrared absorbing dye)
Organic compounds such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, and anthraquinone dyes, which are common infrared absorbing dyes, phthalocyanine, naphthalocyanine And azo-based, thioamide-based, dithiol-based and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-1-280750, JP-A-1-293342, JP-A-2-2074, and JP-A-3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, JP-A-3-42281, JP-A-3-42281 Compounds described in JP-A-3-97589, JP-A-3-103476, JP-A-7-43851, JP-A-7-102179, JP-A-2001-117201 and the like can be mentioned. These can be used alone or in combination of two or more.
[0169]
Examples of the pigment include carbon, graphite, metal, and metal oxide. It is particularly preferable to use furnace black or acetylene black as carbon. The particle size (d50) is preferably 100 nm or less, more preferably 50 nm or less.
[0170]
Fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used as graphite.
[0171]
Any metal can be used as long as it is fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less. The shape may be any shape such as a sphere, a piece, and a needle. In particular, colloidal metal fine particles (Ag, Au, etc.) are preferable.
[0172]
As the metal oxide, a material exhibiting black in the visible light region, or a material having conductivity or a semiconductor itself can be used. Materials exhibiting black in the visible light range include black iron oxide (Fe₃O₄) And black composite metal oxides containing two or more metals described above. The metal oxide is a black composite metal oxide composed of an oxide of two or more metals. Specifically, it is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. These are obtained by the methods disclosed in JP-A-8-27393, JP-A-9-25126, JP-A-9-237570, JP-A-9-241529, JP-A-10-231441 and the like. Can be manufactured. The composite metal oxide that can be used in the present invention is particularly preferably a Cu—Cr—Mn-based or Cu—Fe—Mn-based composite metal oxide. In the case of a Cu-Cr-Mn system, it is preferable to perform a treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides have good coloring with respect to the amount added, that is, good light-to-heat conversion efficiency. These composite metal oxides preferably have an average primary particle diameter of 1 μm or less, and more preferably an average primary particle diameter in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the light-to-heat conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is in the range of 0.01 to 0.5 μm, the light-to-heat conversion ability with respect to the addition amount is improved. It will be better. However, the light-to-heat conversion ability with respect to the added amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable that these composite metal oxide particles are dispersed by a known method before being added to the coating solution for the layer to prepare a dispersion (paste). If the average primary particle diameter is less than 0.01, dispersion becomes difficult, which is not preferable. For dispersion, a dispersant can be used as appropriate. The amount of the dispersant added is preferably 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, based on the composite metal oxide particles. The type of the dispersant is not particularly limited, but it is preferable to use a Si-based surfactant containing a Si element.
[0173]
Examples of the material having conductivity or being a semiconductor include, for example, SnO doped with Sb.₂(ATO), In with Sn added₂O₃(ITO), TiO2, TiO₂(Titanium oxynitride, generally titanium black) or the like. In addition, a core material (BaSO₄, TiO₂, 9Al₂O₃・ 2B₂O, K₂O ・ nTiO₂Etc.) can also be used. Their particle size is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less.
[0174]
A particularly preferred embodiment of the photothermal conversion material is that the infrared absorbing dye and the metal oxide are black composite metal oxides composed of oxides of two or more metals.
[0175]
The addition amount of these light-to-heat conversion materials is 0.1 to 50% by mass, preferably 1 to 30% by mass, and more preferably 3 to 25% by mass with respect to each layer.
[0176]
<Visibility enhancement>
Generally, in the printing industry, there is a work of plate inspection for checking whether an image is correctly formed before printing a printing plate on which an image is formed on a printing material. In order to perform plate inspection, it is preferable that the image formed before printing has good performance on the plate surface, that is, good visibility. Since the printing plate material of the present invention is a processless printing plate material that can be printed without development processing, it is preferable that the optical density of the exposed or unexposed portion be changed by light or heat from exposure.
[0177]
As a method preferably used in the present invention, a method containing a cyanine-based infrared-absorbing dye whose optical density changes upon exposure, a method using a photoacid generator and a compound which changes its color by an acid, and color formation such as a leuco dye There is a method of using a combination of an agent and a developer.
[0178]
In the present invention, the photoacid generator means a compound that generates a Lewis acid or a Bronsted acid upon exposure.
[0179]
Specific examples of the photoacid generator include a diazo compound, an orthoquinonediazide compound, a polyhalogen compound, and an onium salt compound. Further, compounds in which these structures are incorporated in a polymer can also be used.
[0180]
Examples of the diazo compound include diazonium salts disclosed in U.S. Pat. No. 2,063,631 and U.S. Pat. No. 2,667,415 and organic compounds containing a reactive carbonyl group such as aldol and acetal. A diphenylamine-p-diazonium salt, which is a reaction product with a binder, and a formaldehyde condensation product, and these water-soluble diazonium salt compounds were prepared by the method disclosed in JP-A-54-98613.^4-, PF^6-And halogenated Lewis acid salts, allyldiazonium salt compounds, etc. substituted with an anion component or the like.
[0181]
The orthoquinone diazide compound is a compound having at least one orthoquinone diazide group in one molecule, such as 1,2-naphthoquinone-2-diazide-5-sulfonic acid-ethyl ester, 1,2-naphthoquinone-2-diazide-5. -Sulfonic acid-isobutyl ester, 1,2-naphthoquinone-2-diazido-5-sulfonic acid-phenyl ester, 1,2-naphthoquinone-2-diazide-5-sulfonic acid-α-naphthyl ester, 1,2-naphthoquinone -2-diazido-5-sulfonic acid-benzyl ester, 1,2-naphthoquinone-2-diazido-4-sulfonic acid-phenyl ester, 1,2-naphthoquinone-2-diazide-4-sulfonic acid-ethylamide, 1, 2-Naphthoquinone-2-diazide-4-sulfonic acid-fe Ruamido and the like.
[0182]
Examples of the polyhalogen compound include acetophenone containing polyhalogen, such as tribromoacetophenone, trichloroacetophenone, o-nitro-tribromoacetophenone, p-nitro-tribromoacetophenone, m-nitro-tribromoacetophenone, and m-bromo-tribromo. Acetophenone, p-bromo-tribromoacetophenone and the like; and sulfoxides containing polyhalogen, such as bis (tribromomethyl) sulfoxide, dibromomethyl-tribromomethylsulfoxide, tribromomethyl-phenylsulfoxide and the like. Also, sulfones containing polyhalogens, for example, bis (tribromomethyl) sulfone, trichloromethyl-phenylsulfone, tribromomethyl-phenylsulfone, trichloromethyl Other polyhalogen-containing pyrone compounds, triazine compounds, oxadiazole compounds such as ru-p-chlorophenylsulfone, tribromomethyl-p-nitrophenylsulfone 2-trichloromethylbenzothiazolesulfone, 2,4-dichlorophenyl-trichloromethylsulfone, etc. And the like.
[0183]
Onium salt compounds and other photoacid generators include S.I. P. Papas, et al. , Polym. Photochem. , 5, 1, pp. 104-115 (1984), and Ph. Introduced in Coloring Materials, 66 (2), pp. 104-115 (1993).₂I⁺/ SbF^6-A photoacid generator represented by a diallyliodonium salt compound such as, a triallylsulfonium salt compound, a triallyl selenonium salt compound, a dialkylphenacylsulfonium salt compound, a dialkyl-4-phenacylsulfonium salt compound, α -Hydroxymethylbenzoin sulfonate, N-hydroxyiminosulfonate, α-sulfonyloxy ketone, β-sulfonyloxy ketone, iron-arene complex compound (benzene-cyclopentadienyl-iron (II) hexafluorophospho Phosphate, etc.), o-nitrobenzylsilyl ether compound, benzoin tosylate, tri (nitrobenzyl) phosphate and the like.
[0184]
Other examples include ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, organic halogen compounds, o-nitrobenzyl derivatives, iminosulfonates and disulfone compounds.
[0185]
More specifically, for example, compounds represented by the formulas T-1 to T-15 described in Chemical formulas 7 to 9 of JP-A-9-244226 can be exemplified.
[0186]
Among these, more preferred are s-triazine compounds having two or more trihalomethyl groups, and particularly preferred is tris (trichloromethyl) -s-triazine. The content of these photoacid generators is 0.01 to 40% by mass, and preferably 0.1 to 30% by mass, based on the total solid content of the printing plate material.
[0187]
In the present invention, as the compound that changes color by an acid, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used. .
[0188]
Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanil yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Co., Ltd.) Oil Pink # 312 (manufactured by Orient Chemical Industry), Oil Red 5B (manufactured by Orient Chemical Industry), Oil Scarlet # 308 (manufactured by Orient Chemical Industry), Il Red OG (Orient Chemical Co., Ltd.), Oil Red RR (Orient Chemical Co., Ltd.), Oil Green # 502 (Orient Chemical Co., Ltd.), Spiron Red BEH Special (Hodogaya Chemical Co., Ltd.), m-cresol purple, cresol red , Rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p-diethylaminophenyliminonaphthoquinone, 2-carbostarylamino-4-p-dihydrooxyethyl Amino-phenylimino naphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4-p-diethylaminophenylimino-5-pyrazolone and the like. It is.
[0189]
In addition, an organic dye such as an arylamine can be used as the compound that develops a color with an acid. Arylamines suitable for this purpose include not only simple arylamines such as primary and secondary aromatic amines, but also so-called leuco dyes, examples of which include the following.
[0190]
Diphenylamine, dibenzylaniline, triphenylamine, diethylaniline, diphenyl-p-phenylenediamine, p-toluidine, 4,4'-biphenyldiamine, o-chloroaniline, o-bromoaniline, 4-chloro-o-phenylenediamine , O-bromo-N, N-dimethylaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, aniline, 2,5-dichloroaniline, N-methyldiphenylamine, o-toluidine, p, p'- Tetramethyldiaminodiphenylmethane, N, N-dimethyl-p-phenylenediamine, 1,2-dianilinoethylene, p, p ′, p ″ hexamethyltriaminotriphenylmethane (leuco crystal violet), p, p′-tetra Methyldiamino Riphenylmethane, p, p'-tetramethyldiaminodiphenylmethylimine, p, p ', p "-triamino-o-methyltriphenylmethane, p, p', p" -triaminotriphenylcarbinol, p, p'-tetramethylaminodiphenyl-4-anilinonaphthylmethane, p, p ', p "-triaminophenylmethane, p, p', p" -hexapropyltriaminotriphenylmethane and the like.
[0191]
In the present invention, as the color developer, any acidic substance used as an electron acceptor in the thermosensitive recording medium can be used, for example, an acidic acid clay kaolin, an inorganic acid such as zeolite, an aromatic carboxylic acid, an anhydride thereof or the like. Metal salts, organic sulfonic acids, other organic acids, phenolic compounds, methylolates of the phenolic compounds, organic developers such as salts or complexes of the phenolic compounds, and the like, among which phenolic compounds Methylolates and salts of phenolic compounds (including complex salts unless otherwise specified) are preferred.
[0192]
Among these developers, specific examples of organic developers include phenol, 4-phenylphenol, 4-hydroxyacetophenone, 2,2'-dihydroxydiphenyl, and 2,2'-methylenebis (4-chlorophenol). 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-isopropylidenediphenol (also known as bisphenol A), 4,4'-isopropylidenebis (2-chlorophenol), 4,4'-isopropylidenebis (2-methylphenol), 4,4'ethylenebis (2-methylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), 1,1- Bis (4-hydroxyphenyl) -cyclohexane, 2,2'-bis (4-hydroxyphenyl) -n-heptane, 4,4'- Phenolic compounds such as clohexylidenebis (2-isopropylphenol) and 4,4'-sulfonyldiphenol; methylolated products of the phenolic compounds; salts of the phenolic compounds; salicylic acid anilide; novolak phenolic resins; Benzyl hydroxybenzoate and the like.
[0193]
In the present invention, a leuco dye such as a triphenylmethanelactone type can be used as the color former used together with the color developer.
[0194]
Such leuco dyes include, for example, crystal violet lactone, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) aminofluoran, malachite green lactone, 3,3-bis (1-ethyl-2-methyldol-3-yl) phthalide, 3-diethylamino-6-methyl -7-anilinofluoran, 2-anilino-3-methyl-6- (N-ethyl-p-toluidino) fluoran, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilino Fluorane, 3-piperidino-6-methyl-7-anilinofluoran and the like.
[0195]
The color former and the color developer are usually used in a range in which the weight ratio of the color developer / the color former is 0.1 / 1 to 5/1, and especially, the weight ratio is 0.5 / 1 to 3 /. A range of 1 is preferable.
[0196]
<Constituent layer on the opposite side of the image forming functional layer>
In the present invention, it is preferable that the support has at least one constituent layer on the side of the support opposite to the image forming functional layer in order to prevent a change in physical properties during handling and storage. Preferred constituent layers are an undercoat layer, a hydrophilic binder-containing layer and a hydrophobic binder-containing layer, and the binder-containing layer may be provided on the undercoat layer.
[0197]
As the undercoat layer, the above-described undercoat layer of the support is preferable.
The hydrophilic binder is not particularly limited as long as it is hydrophilic, but polyvinyl alcohol (PVA), which is a resin having a hydroxyl group as a hydrophilic structural unit, cellulose resin (methyl cellulose (MC), ethyl cellulose (EC), Hydroxyethylcellulose (HEC), carboxymethylcellulose (CMC), etc.), chitins and starch; resins having ether linkages: polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG) and polyvinyl ether (PVE) Polyacrylamide (PAAM) and polyvinylpyrrolidone (PVP), which are resins having an amide group or an amide bond. Also, polyacrylates having a carboxyl group as a dissociable group, maleic acid resins, alginates and gelatins; polystyrene sulfonates having a sulfone group; amino groups, imino groups, tertiary amines and quaternary ammonium salts. Polyallylamine (PAA), polyethyleneimine (PEI), epoxidized polyamide (EPAm), polyvinylpyridine and gelatins.
[0198]
The hydrophobic binder is not particularly limited as long as it is hydrophobic as the binder. For example, polymers derived from α, β-ethylenically unsaturated compounds, such as polyvinyl chloride, post-chlorinated polyvinyl chloride, and vinyl chloride Made from copolymers of vinylidene chloride, copolymers of vinyl chloride and vinyl acetate, polyvinyl acetate and partially hydrolyzed polyvinyl acetate, made of polyvinyl alcohol as a starting material, only part of the vinyl alcohol units react with aldehydes repeatedly. Polyvinyl acetals, preferably polyvinyl butyral, copolymers of acrylonitrile and acrylamide, polyacrylates, polymethacrylates, polystyrene and polyethylene or mixtures thereof.
[0199]
Further, the hydrophobic binder may be one obtained from an aqueous dispersion resin (polymer latex) described in paragraphs 0033 to 0038 of JP-A-2002-258469, as long as the finished printing plate material surface is hydrophobic. .
[0200]
In addition, in order to prevent color misregistration in color printing due to misregistration of the printing plate during printing during printing, and to prevent color misregistration due to misregistration of the printing plate during printing, the average particle size of the outermost surface layer of the constituent layers is set in the present invention. It is preferable to include a matting agent having a diameter of 1 μm or more and less than 20 μm.
[0201]
Preferred examples of the matting agent include inorganic fine particles having a new Mohs hardness of 5 or more and organic matting agents. Examples of the inorganic fine particles having a new Mohs hardness of 5 or more include metal oxide particles (silica, alumina, titania, zirconia, iron oxide, chromium oxide, and the like), metal carbide particles (silicon carbide, and the like), boron nitride particles, and diamond particles. No. Examples of the organic matting agent include starch described in US Pat. No. 2,322,037, starch derivatives described in BEP 625,451 and GBP 981,198, etc., and JP-B-44-3643. Polyvinyl alcohol, polystyrene or polymethacrylate described in CHP 330, 158, etc., polyacrylonitrile described in US Pat. No. 3,079,257, etc., and polycarbonate described in US Pat. No. 3,022,169, etc. can give.
[0202]
The added amount of these matting agents is 1 m²It is preferably 0.1 g or more and less than 10 g.
[0203]
In the present invention, the surface roughness of the surface on the opposite side of the image forming layer is adjusted to a Ra value of 0.1 μm or more and less than 2 μm by adjusting the particle size, the addition amount and the amount of the binder of the matting agent. It is preferable that When the thickness is less than 0.1 μm, there is a concern that a problem occurs in the transportability of the printing plate material due to a high friction coefficient or the like, or a problem may occur in attaching the printing plate material to a printing machine. On the other hand, a rough surface of 2 μm or more may damage the coating layer formed on the opposite surface when the printing plate material is wound around a roll during the production of the printing plate material or when the printing plate material is fixed on the plate cylinder. There is also a concern that the printing plate material surface partially protrudes due to pushing up from the side, and printing pressure concentrates on that portion, resulting in poor printing durability.
[0204]
Further, the laser recording device or the processless printing machine has a sensor for controlling the transport of the printing plate inside the device, and in order to perform these controls without delay, in the present invention, in the constituent layers, Preferably contains a dye and a pigment. As the coloring matter and the pigment, the infrared absorbing coloring matter and the pigment used in the above-mentioned light-to-heat conversion material are preferably used. Further, the constituent layer may contain a known surfactant.
[0205]
<Packaging materials>
After the printing plate material manufactured as described above is cut into a desired size, the printing plate material is wound into a roll and packaged for storage until exposure described below is performed. In this case, in order to withstand long-term storage, as a packaging material, an oxygen permeability of 50 ml / atm · m described in JP-A-2000-206653 is used.²-It is preferable that the package is packaged with a packaging material of 30 ° C · day or less. As another preferred embodiment, a water permeability of 10 g / atm · m described in JP-A-2000-206653 is used.²It is preferable that the package is packed with a packaging material having a temperature of 25 ° C. · day or less.
[0206]
<printing>
The printing plate material on which an image has been formed as described above is preferably printed without performing a developing process. The printing plate material after image formation is directly attached to the plate cylinder of the printing press, or the printing plate material is attached to the plate cylinder of the printing press to form an image, and the water supply roller and / or ink supply is performed while rotating the plate cylinder. The non-image portion of the image forming layer can be removed by bringing the roller into contact with the printing plate material.
[0207]
The step of removing the non-image portion of the image forming layer in the printing plate material of the present invention can be performed in a normal printing sequence using a PS plate, so that there is no need to extend the working time by so-called on-press development processing. Therefore, it is effective for cost reduction.
[0208]
Furthermore, in the printing method of the present invention, it is preferable that the printing method further includes a step of drying the surface of the printing plate material after the image is formed and before the surface of the printing plate material and the water supply roller or the ink supply roller are in contact with each other on the printing press. . In the printing method of the present invention, it is considered that the image intensity gradually increases immediately after image formation. In the case of a laser-based external drum method (the above-described method), since it generally takes about three minutes from the start to the end of exposure, there is a concern that the image intensity differs between the exposure start part and the end part at the end of exposure. By providing the drying step, the difference in image intensity can be reduced to a level that does not cause any problem.
[0209]
When printing the printing plate material of the present invention, the effect of the present invention is remarkably exhibited when an ink that does not use a petroleum-based volatile organic compound, that is, a so-called environmentally friendly ink is used.
[0210]
Specific examples of the environmentally-friendly ink used in the present invention include soybean oil ink Naturalis 100 manufactured by Dainippon Ink and Chemicals, VOC Zero Ink TK Hi-Echo SOY1 manufactured by Toyo Ink, process ink manufactured by Tokyo Ink. Sol seibo and the like.
[0211]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0212]
Example 1
<< Preparation of support >>: Preparation of plastic film
(Support 1: polyethylene terephthalate support)
Using terephthalic acid and ethylene glycol, PET having an IV (intrinsic viscosity) of 0.66 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) was obtained according to a conventional method. This is pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, quenched on a cooling drum at 50 ° C., and heat-fixed so that the average film thickness becomes 190 μm. A stretched film was produced. The film was longitudinally stretched 1.1 times at a stretching temperature of 102 ° C. in the first stage stretching and 2.6 times at 110 ° C. in the second stage stretching. Next, the film was transversely stretched 1.8 times at 120 ° C. with a tenter. Thereafter, after heat-setting at 240 ° C. for 20 seconds, it was relaxed by 4% in the lateral direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling was performed on both ends, and after cooling to 40 ° C., winding was performed at 83.3 N / m. The width (film formation width) of the polyethylene terephthalate film thus obtained was 2.5 m. The thickness distribution of the obtained support was 12%.
[0213]
(Support 2: polyethylene terephthalate support)
Using terephthalic acid and ethylene glycol, PET having an IV (intrinsic viscosity) of 0.66 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) was obtained according to a conventional method. This is pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, quenched on a cooling drum at 50 ° C., and heat-fixed so that the average film thickness becomes 190 μm. A stretched film was produced. This was longitudinally stretched by 1.3 times at 102 ° C. in the former stretching and 2.6 times at 110 ° C. in the latter stretching. Then, it was horizontally stretched 4.5 times at 120 ° C. with a tenter. After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the horizontal direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling was performed on both ends, and after cooling to 40 ° C., winding was performed at 47.04 N / m. The width (film formation width) of the polyethylene terephthalate film thus obtained was 2.5 m. The thickness distribution of the obtained support was 3%.
[0214]
(Support 3: polyethylene terephthalate support)
Using terephthalic acid and ethylene glycol, PET having an IV (intrinsic viscosity) of 0.66 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) was obtained according to a conventional method. This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, quenched on a cooling drum at 50 ° C., and heat-fixed to a thickness of 350 μm. A stretched film was produced. This was longitudinally stretched at a stretching temperature of 1.5 times at 102 ° C. in the former stage and at 4.0 ° C. at 110 ° C. in the latter stage. Next, the film was stretched 5.0 times at 120 ° C. with a tenter. After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the horizontal direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling was performed on both ends, and after cooling to 40 ° C., winding was performed at 83.3 N / m. The width (film formation width) of the polyethylene terephthalate film thus obtained was 2.5 m.
[0215]
《Preparation of undercoated support》
8 W / m on both sides of each film of supports 1, 2 and 3 obtained above²・ A corona discharge treatment (8 W / m 2) was performed after applying the following undercoating coating liquid a on one surface so as to have a dry film thickness of 0.8 μm.²), The undercoating coating solution b was applied to a dry film thickness of 0.1 μm and dried at 180 ° C. for 4 minutes (undercoating surface A). As shown in Table 5, the undercoating solution c-1, c-2, or c-3 shown below was applied on the opposite surface to a dry film thickness of 0.8 μm, and then subjected to corona discharge treatment (8 W / M²Min), the undercoating coating solution d-1, d-2 or d-3 was applied to a dry film thickness of 1.0 μm and dried at 180 ° C. for 4 minutes (undercoating surface B). . Further, the surface roughness of the surface of the support 2 on the side of the undercoating surface B was measured, and the Ra value was 0.8 μm.
[0216]
<< Undercoating liquid a >>

<< Undercoat coating solution b >>

[0217]
Embedded image

[0218]
<< Undercoat coating liquid c-1 >>

<< Undercoating coating solution d-1 >>

Component d-11;
Anionic polymer compound comprising a copolymer of sodium styrene sulfonate / maleic acid = 50/50
Component d-12;
Three-component copolymer latex consisting of styrene / glycidyl methacrylate / butyl acrylate = 40/40/20
Component d-13;
Polymer activator consisting of styrene / sodium isoprenesulfonate = 80/20
[0219]
Embedded image

[0220]
<< Undercoating coating liquid c-2 >>

<< Undercoating coating solution d-2 >>

<< Undercoating liquid c-3 >>

Next, the surface of each undercoat layer was subjected to plasma processing under the following plasma processing conditions.
[0221]
《Plasma treatment conditions》
Using a batch type atmospheric pressure plasma processing apparatus (AP-I-H-340, manufactured by EC Chemical Co., Ltd.), high-frequency output was 4.5 kW, frequency was 5 kHz, processing time was 5 seconds, and argon was used as a gas condition. Plasma treatment was performed with nitrogen and hydrogen at a volume ratio of 90% and 5%, respectively.
[0222]
《Heat treatment conditions》
The support after slitting to a width of 1.25 m was subjected to a low tension heat treatment at 180 ° C. for 1 minute at a tension of 2 hPa.
[0223]
<< Preparation of printing plate material >>
<< Preparation of printing plate materials 101-104 >>
Immediately before applying the hydrophilic layer, the undercoated support was subjected to a heat treatment at 100 ° C. for 30 seconds and dried, and was covered with a moisture-proof sheet to prevent moisture in the air from entering. A portion of the support sample was sampled and the moisture content was measured. As a result, Support 1 was 1.2%, Support 2 was 0.2%, and Support 3 was 1.2%. With respect to those covered, the sheet was removed and immediately applied.
[0224]
The undercoated support 1, the support 2 and the support 3, respectively, the coating solution for the hydrophilic layer 1 shown in Table 2 (preparation method is shown below) and the hydrophilic solution shown in Table 3 Each of the coating solutions for the conductive layer 2 (preparation method is described below) was dried in a combination shown in Table 5 using a wire bar at a drying amount of 2.5 g / m², 0.6 g / m²After drying at 120 ° C. for 3 minutes, a heat treatment was performed at 60 ° C. for 24 hours. Thereafter, each of the coating solutions for the image forming functional layers shown in Table 4 was dried using a wire bar to obtain a coating weight of 0.6 g / m 2.²After drying at 50 ° C. for 3 minutes, a seasoning treatment was performed at 50 ° C. for 72 hours. Thus, printing plate materials 101 to 104 were produced. The surface electric resistance at 25 ° C. and 25% RH after application was 10% for samples 101 and 104.¹²Ω, and samples 102 and 103 are 10⁸Ω.
[0225]
<< Preparation of coating liquid for hydrophilic layer 1 >>
Each material shown in Table 2 was sufficiently stirred and mixed with a composition shown in Table 2 using a homogenizer, and then filtered to prepare a coating solution for the hydrophilic layer 1. The details of each material are as follows, and the numerical values in the table represent parts by mass.
[0226]
[Table 2]

[0227]
<< Preparation of coating liquid for hydrophilic layer 2 >>
Each material shown in Table 3 was sufficiently stirred and mixed with a composition shown in Table 3 using a homogenizer, and then filtered to prepare a coating solution for the hydrophilic layer 2. The details of each material are as follows, and the numerical values in the table represent parts by mass.
[0228]
[Table 3]

[0229]
(* 1) Acrylic resin a: produced by the following production method.
A reactor equipped with a stirrer, a temperature controller and a reflux tube was charged with 65 parts of n-butyl acetate, heated to 110 ° C., and a mixture of the following monomer compositions was added dropwise over 3 hours.
Methyl methacrylate 60 parts
i-butyl methacrylate 15 parts
7.5 parts of i-butyl acrylate
2-hydroxyethyl acrylate 10 parts
2.5 parts of 2-hydroxyethyl methacrylate
Acrylic acid 5 parts
Azobisisobutyronitrile 2.5 parts
After the dropwise addition, the temperature was maintained for 1 hour, a mixed solution of 0.5 parts of azobisisobutyronitrile and 10 parts of n-butyl acetate was added dropwise over 1 hour, and the temperature was maintained for 1 hour. Thereafter, the mixture was neutralized by 0.7 equivalent with N, N-dimethylethanolamine, and deionized water was added thereto to dilute the resin until the resin concentration became 30% by mass, to obtain an aqueous acrylic resin a. The resulting resin a had a hydroxyl value of 59 and an acid value of 39.
[0230]
<< Preparation of coating solution for image forming functional layer >>
[0231]
[Table 4]

[0232]
Embedded image

[0233]
The printing plate material prepared as described above was cut into a length of 73 cm and a length of 32 m, and was wound around a core made of cardboard having a diameter of 7.5 cm to prepare a roll-shaped sample. Further, the sample is₂O₃It was wrapped with a 150 cm × 2 m wrapping material made of PET (12 μm) / Ny (15 μm) / CPP (70 μm), and the end face was heat-sealed to shut off the outside air. The prepared packaged printing plate material sample was heated at 50 ° C. and 80% RH for 7 days under forced deterioration conditions.
[0234]
For packaging materials, Al₂O₃PET represents alumina-deposited PET (polyethylene terephthalate), Ny represents nylon, and CPP represents casting polypropylene. The oxygen permeability of the packaging material is 1.7 ml / atm · m²・ 30 ° C ・ day, moisture permeability 1.8g / atm ・ m²・ 25 ° C. ・ day
[0235]
《Measurement of stiffness》
A sample is cut out to a size of 20 cm × 10 cm, and the sample is placed on a flat table using a film stiffness tester UT-200GR (manufactured by Toyo Seiki Co., Ltd.). Was fixed to a table, the center 10 cm was bent 1 cm above the table, and the load when the top was pushed down with a needle and pressed down 3 mm was evaluated.
[0236]
<< Evaluation of printing plate materials 101-104 >>
(A) Image formation by infrared laser method
After cutting the above-mentioned sample according to the exposure size, it was wound around an exposure drum and fixed using an exposure apparatus having a configuration shown in FIGS. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm was used, and the exposure energy was 100 to 350 mJ / cm.²The exposure energy was changed stepwise every 50 mJ until 2400 dpi (dpi represents the number of dots per 2.54 cm), an image was formed with 175 lines, and a printing plate sample was prepared.
[0237]
The exposure drum used for exposure was 270 mm in diameter and 850 mm in width. The exposure conditions were 850 rotations of the drum per minute, and the image plane laser power was 270 mW.
[0238]
(B) The printing plate samples 101 to 104 on which the images were formed were evaluated for various properties as printing plates by the following printing methods.
[0239]
《Printing method》
Using DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd. as a printing device, coated paper, a 2% by mass solution of Astromark 3 (manufactured by Niken Kagaku Kenkyusho) as a dampening solution, and Toyo Ink Co., Ltd. as an environmentally friendly ink Was printed using Toyo King Hi-Echo SOY1M Red.
[0240]
<< Evaluation of initial ink deposition >>
The printing start sequence was performed using the PS plate printing sequence, and the number of sheets on which the ink stain on the non-image area was eliminated was evaluated. The smaller the number of sheets, the better the ink deposition property. Observation of the plate after printing revealed that the non-image areas of the material according to the invention had been removed.
[0241]
《Evaluation of dimensional stability》
Prior to printing, scratches having a width of 25 μm were formed on the plate surface at two locations 50 cm apart. The dimensional change (μm) was measured by how much the distance between the two flaws changed between the printing paper after printing 100 sheets and the printing paper after printing 3000 sheets. The smaller the change, the better.
[0242]
《Evaluation of printing durability》
The number of prints in which half or more of the 3% halftone dot image was missing was obtained (printing was performed up to 30,000). The higher the number of prints, the better.
[0243]
Table 5 shows the results obtained as described above.
[0244]
[Table 5]

[0245]
Example 2
<< Preparation of printing plate material >>
On the image forming functional layer of the printing plate material produced in the same manner as the printing plate material 102 produced in Example 1, the following overcoat layer was further dried with a wire bar at a dry weight of 0.4 g / m.²And dried at 50 ° C. for 3 minutes. Further, the following back layer was dried on a side opposite to the support from the image forming functional layer side using a wire bar to a dry weight of 1.5 g / m 2.²And dried at 50 ° C. for 20 minutes to prepare a printing plate material 201. Further, a seasoning treatment was performed at 50 ° C. for 24 hours, and then the humidity was controlled at 23 ° C. and a relative humidity of 20% for 24 hours.
[0246]
<< Overcoat layer coating solution >>
15% by mass of 98% hydrolyzed polyvinyl acetate (weight average molecular weight 200,000)
Hexamethylene diisocyanate 1 part by mass
Matting agent (Amorphous silica, average particle size 2 μm) 2 parts by mass
82 parts by mass of water
<< Back layer coating solution >>
Polyacrylic acid (trade name: Julimer AC-10H, Nippon Pure Chemical, average molecular weight 20)
10,000 water-soluble resin) 16 parts by mass
Carbodiimide (crosslinking agent) 2 parts by mass
Matting agent (amorphous silica, average particle size 3.5 μm) 2 parts by mass
80 parts by weight of water
When the surface roughness of the surface of the back layer was measured, the Ra value was 0.9 μm.
[0247]
Evaluation was performed in the same manner as in Example 1. In the evaluation of the printing durability in Example 2, the number of printed sheets on which the solid portion was blurred was obtained (printing was performed up to 50,000 sheets).
[0248]
Table 6 shows the results obtained as described above.
[0249]
[Table 6]

[0250]
Example 3
<< Preparation of printing plate material >>
The following coating solution was applied to the surface A of the undercoated support same as that used for the printing plate material 103 prepared in Example 1, heated and dried (180 ° C., 30 seconds), and dried to a film thickness of 0.2 g / m²Was formed.
[0251]
<< Intermediate layer coating liquid 1 >>
Polyester latex dispersion (AA-64, solid content 30% by mass, Japan NSC
5 g
15 g of tin oxide-antimony oxide aqueous dispersion (average particle size 0.1 μm 17 mass%)
Polyoxyethylene alkyl phenyl ether (Emulgen 911, 10% by mass
Aqueous solution, manufactured by Kao Corporation) 2.0 g
80 g of distilled water
Next, the following coating solution was applied on the intermediate layer, and was dried by heating (100 ° C., 10 minutes) to obtain a dry mass of 5 g / m 2.²Was formed.
[0252]
<< Hydrophilic layer coating solution >>

<Preparation of sol-gel preparation liquid>
A liquid having the following composition was aged at room temperature for 1 hour to prepare a sol-gel preparation liquid.
8.5 g of tetraethoxysilane
1.8 g of methanol
15.0 g of water
Phosphoric acid 0.015g
Next, the following heat-sensitive recording layer coating solution was applied onto the hydrophilic layer and dried (100 ° C., 2 minutes) to obtain a dry applied mass of 0.6 g / m 2.²To form a lithographic printing plate 301.
[0253]
《Heat-sensitive recording layer coating solution》
Sulfonic acid-generating polymer compound (average molecular weight: about 30,000) B-1 1.0 g
Infrared absorbent A (structure below) 0.2 g
Victoria Pure Blue BOH counter ion was 1-naphthalene-sulfonic acid
Dye 0.05g
Fluorinated surfactant
(MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.02 g
15 g of methyl ethyl ketone
Propylene glycol monomethyl ether 2g
8 g of methyl alcohol
Dimethylformamide 1g
[0254]
Embedded image

[0255]
The obtained printing plate was evaluated in the same manner as in Example 1.
Table 7 shows the results obtained as described above.
[0256]
[Table 7]

[0257]
【The invention's effect】
A printing plate material having a plastic support with high printing durability was obtained, which was free from dimensional deviation and initial ink deposition deterioration due to insufficient exposure even when exposed with a large exposure drum.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state in which a printing plate material is wound around an exposure drum.
FIG. 2 is a cross-sectional view illustrating a basic configuration of an exposure drum.
FIG. 3 is an overall configuration diagram showing a feeding unit and an exposure unit for feeding a printing plate material to an exposure unit.
[Explanation of symbols]
1 pressure roll
2 suction holes
3 printing plate materials
5 Exposure drum
7 Feeding part
8 Optical writing means
9 Case
10 Pressure reducing valve

Claims (11)

A printing plate material having an image forming functional layer on a plastic support, which is formed by irradiating a laser beam on the exposure drum with an image recording device having an exposure drum having a diameter of 250 mm or more to form an image. A printing plate material, characterized in that the stiffness (ST) at 23 ° C. and 48% RH is 30 g ≦ ST ≦ 120 g. The printing plate material according to claim 1, wherein the image forming functional layer contains heat fusible fine particles or heat fusible fine particles. The printing plate material according to claim 1, further comprising at least one hydrophilic layer between the plastic support and the image forming functional layer. The printing plate material according to any one of claims 1 to 3, wherein an average film thickness of the plastic support is in a range of 100 µm to 300 µm. The printing plate material according to claim 3, wherein at least one of the hydrophilic layers has a porous structure. The printing plate material according to any one of claims 1 to 5, wherein any one layer on the plastic support contains a light-to-heat conversion material. The printing plate material according to any one of claims 1 to 6, wherein the water content of the plastic support is 0.5% by mass or less. The printing plate material according to any one of claims 1 to 7, wherein the printing plate material is wound in a roll shape. A printing plate material wound into a roll having an image forming functional layer on a plastic support is fed, and the fed printing plate material is wound around an exposure drum having a diameter of 250 mm or more, and is held by close contact with a reduced pressure. The image recording method of irradiating a laser beam according to image data from a surface having a forming functional layer, converting the laser beam absorbed by the printing plate material into heat, and forming an image on the printing plate material by the converted heat, An image recording method, wherein a stiffness (ST) of a printing plate material at 23 ° C. and 48% RH is 30 g ≦ ST ≦ 120 g. The printing plate material according to any one of claims 1 to 8, which is wound around an exposure drum having a diameter of 250 mm or more, held in close contact under reduced pressure, irradiated with a laser beam to form an image, and then subjected to wet development processing. A method for producing a printing plate, characterized by producing a printing plate without performing the method. The printing plate material according to any one of claims 1 to 8, which is wound around an exposure drum having a diameter of 250 mm or more, held in close contact under reduced pressure, irradiated with a laser beam to form an image, and then subjected to wet development processing. A printing method in which the printer is attached to a printing press and printed.

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