JP2004174912A - Printing plate material and printing method using this material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To upgrade printability, especially inking property at the start of printing and resistance to plate wear hardly having a color drift, when a large number of sheets are printed using a plurality of printing plates as is the case of color printing. <P>SOLUTION: This printing plate material has at least a single imaging functional layer containing a heat-melting particulate or a heat-fusion bonding particulate formed on one side of a plastic film support. In addition, the printing plate material is made to have the absolute value of thermal change rate H(%) limited within 0.05% represented by the following formula: The thermal change rate H is represented by 100 × (L-D)/L (wherein L is the length of the printing plate material when the moisture is conditioned, at 23°C, 48%RH for one day and D is the length of the printing plate material when the moisture is conditioned, at 23°C, 48%RH for one day after thermal treatment at 128°C for one minute). <P>COPYRIGHT: (C)2004,JPO

Description

【００８８】
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。
【００８９】
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。
【００９０】
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。
【００９１】
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。
【００９２】
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。
【００９３】
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。
【００９４】
〈親水性層〉
本発明に係る親水性層について説明する。ここで、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、インク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。
【００９５】
請求項５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。
【００９６】
（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。
【００９７】
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。
【００９８】
（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。
【００９９】
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。
【０１００】
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。
【０１０１】
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。
【０１０２】
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。
【０１０３】
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。
【０１０４】
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。
【０１０５】
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。
【０１０６】
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。
【０１０７】
（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。
【０１０８】
（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。
【０１０９】
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。
【０１１０】
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。
【０１１１】
（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。
【０１１２】
（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。
【０１１３】
（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。
【０１１４】
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。
【０１１５】
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。
【０１１６】
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。
【０１１７】
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。
【０１１８】
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。
【０１１９】
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。
【０１２０】
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。
【０１２１】
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。
【０１２２】
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、多糖類を用いることが好ましい。
【０１２３】
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。
【０１２４】
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。
【０１２５】
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。
【０１２６】
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。
【０１２７】
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。
【０１２８】
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。
【０１２９】
また、後述する光熱変換素材を含有することもできる。光熱変換素材としては、粒子状素材の場合は粒径が１μｍ未満であることが好ましい。
【０１３０】
（粒径が１μｍ以上の無機粒子もしくは無機素材で被覆された粒子）
本発明で用いることのできる無機粒子としては、例えば、シリカ、アルミナ、チタニア、ジルコニアなど、公知の金属酸化物粒子を用いることができるが、塗布液中での沈降を抑制するために、多孔質な金属酸化物粒子を用いることが好ましい。多孔質な金属酸化物粒子としては、前述の多孔質シリカ粒子や多孔質アルミノシリケート粒子を好ましく用いることができる。
【０１３１】
また、無機素材で被覆された粒子としては、例えば、ポリメチルメタアクリレートやポリスチレンといった有機粒子を芯材とし、芯材粒子よりも粒径の小さな無機粒子で被覆した粒子が挙げられる。無機粒子の粒径としては、芯材粒子の１／１０〜１／１００程度であることが好ましい。また、無機粒子としては、同様にシリカ、アルミナ、チタニア、ジルコニアなど、公知の金属酸化物粒子を用いることができる。被覆方法としては、種々の公知の方法を用いることができるが、ハイブリダイザのような空気中で芯材粒子と被覆材粒子とを高速に衝突させて芯材粒子表面に被覆材粒子を食い込ませて固定、被覆する乾式の被覆方法を好ましく用いることができる。
【０１３２】
また、有機粒子の芯材を金属メッキした粒子も用いることができる。このような粒子としては、例えば、樹脂粒子に金メッキを施した積水化学工業社製の「ミクロパールＡＵ」等が挙げられる。
【０１３３】
粒径は、１〜１０μｍが好ましく、更に好ましくは、１．５〜８μｍであり、特に好ましくは、２〜６μｍである。
【０１３４】
本発明では、粒径が１μｍ以上の粒子の添加量としては、親水性層全体の１〜５０質量％であることが好ましく、５〜４０質量％であることがより好ましい。親水性層全体としては、有機樹脂やカーボンブラック等の炭素を含有する素材の含有比率が低いことが親水性を向上させるために好ましく、これらの素材の合計が９質量％未満であることが好ましく、５質量％未満であることがより好ましい。
【０１３５】
〈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。
【０１３６】
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。
【０１３７】
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。
【０１３８】
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。
【０１３９】
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。
【０１４０】
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。
【０１４１】
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。
【０１４２】
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。
【０１４３】
〈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。
【０１４４】
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。
【０１４５】
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。
【０１４６】
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。
【０１４７】
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。
【０１４８】
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。
【０１４９】
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。
【０１５０】
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。
【０１５１】
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。
【０１５２】
〈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。
【０１５３】
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。
【０１５４】
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。
【０１５５】
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。
【０１５６】
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。
【０１５７】
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。
【０１５８】
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。
【０１５９】
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。
【０１６０】
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。
【０１６１】
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。
【０１６２】
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。
【０１６３】
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。
【０１６４】
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。
【０１６５】
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。
【０１６６】
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。
【０１６７】
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。
【０１６８】
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。
【０１６９】
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。
【０１７０】
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。
【０１７１】
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。
【０１７２】
〈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。
【０１７３】
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。
【０１７４】
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。
【０１７５】
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。
【０１７６】
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。
【０１７７】
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。
【０１７８】
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。
【０１７９】
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。
【０１８０】
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。
【０１８１】
〈露光〉
本発明は、また印刷版材料をサーマルヘッドもしくはサーマルレーザーを用いて画像を形成した後に、画像形成層の非画像部を印刷機上で除去する工程を含む印刷方法も提供するものである。
【０１８２】
本発明の印刷版材料の画像形成は熱により行うことができるため、感熱プリンタで用いられるようなサーマルヘッドによっても画像形成が可能であるが、特にサーマルレーザーによる露光によって画像形成を行うことが好ましい。
【０１８３】
本発明に関する露光に関し、より具体的には、赤外および／または近赤外領域で発光する、すなわち７００〜１５００ｎｍの波長範囲で発光するレーザーを使用した走査露光が好ましい。レーザーとしてはガスレーザーを用いてもよいが、近赤外領域で発光する半導体レーザーを使用することが特に好ましい。
【０１８４】
本発明の走査露光に好適な装置としては、該半導体レーザーを用いてコンピュータからの画像信号に応じて印刷版材料表面に画像を形成可能な装置であればどのような方式の装置であってもよい。
【０１８５】
一般的には、
（１）平板状保持機構に保持された印刷版材料に一本もしくは複数本のレーザービームを用いて２次元的な走査を行って印刷版材料全面を露光する方式、
（２）固定された円筒状の保持機構の内側に、円筒面に沿って保持された印刷版材料に、円筒内部から一本もしくは複数本のレーザービームを用いて円筒の周方向（主走査方向）に走査しつつ、周方向に直角な方向（副走査方向）に移動させて印刷版材料全面を露光する方式、
（３）回転体としての軸を中心に回転する円筒状ドラム表面に保持された印刷版材料に、円筒外部から一本もしくは複数本のレーザービームを用いてドラムの回転によって周方向（主走査方向）に走査しつつ、周方向に直角な方向（副走査方向）に移動させて印刷版材料全面を露光する方式があげられる。
【０１８６】
本発明に関しては特に（３）の走査露光方式が好ましく、特に印刷装置上で露光を行う装置においては、（３）の露光方式が用いられる。
【０１８７】
こ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できる。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ク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。
【０１８８】
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。
【０１８９】
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ク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。サーマルレーザーで一般的な外面ドラム方式（前述の（３）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。
【０１９０】
【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。
【０１９１】
実施例１
《支持体の作製》：ポリエステルフィルムの作製
（ポリエチレンテレフタレート１；ＰＥＴ１）
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、延伸温度は、前段延伸が１０２℃で１．０倍に、後段延伸は１１０℃で４．１倍に縦延伸した。ついでテンターで１２０℃で６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８３．４Ｎ／ｍで巻き取った。このようにして得たＰＥＴフィルムの幅（製膜幅）は２．５ｍであった。
【０１９２】
（ポリエチレンテレフタレート２；ＰＥＴ２）
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、延伸温度は、前段延伸が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４．８ｋｇ／ｍで巻き取った。このようにして得たＰＥＴフィルムの幅（製膜幅）は２．５ｍであった。
【０１９３】
（ポリエチレン−２，６−ナフタレート；ＰＥＮ３）
２，６−ナフタレンジカルボン酸メチルとエチレングリコールを用い、常法に従いＩＶ（固有粘度）＝０．５５（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ＰＥＮを得た。これをペレット化した後１５０℃で４時間乾燥し、３１０℃で溶融後Ｔ型ダイから押し出し、８０℃の冷却ドラム上で急冷し未延伸フィルムを作製した。これを前段延伸が１３２℃で１．２倍に、後段延伸は１４０℃で２．７倍に縦延伸した。ついでテンターで１４５℃で４．０倍に横延伸した。この後、２５０℃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、両端にナール加工を行い、４０℃に冷却後４．８ｋｇ／ｍで巻き取った。このようにして得たＰＥＮフィルムの幅（製膜幅）は２．５ｍであった。また、ＰＥＮ３の平均膜厚（μｍ）は１９０μｍであった。
【０１９４】
《下引き済み支持体の作製》
上記で得られたＰＥＴ１、２及びＰＥＮ３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、表５に記載のように、一方の面に下記下引き塗布液ａ−１またはａ−２を乾燥膜厚０．８μｍになるように塗設後に、下引き塗布液ｂを塗布し、各々１８０℃、４分間乾燥させた（下引き面Ａ）。
【０１９５】
また反対側の面に下記導電層と中間層を順次塗布し１８０℃、４分間で乾燥させ、これらの層の上に下記下引き塗布液ｃ−１またはｃ−２を乾燥膜厚０．８μｍになるように塗設しそれぞれ１８０℃、４分間乾燥させた（下引き面Ｂ）。塗布後の２５℃、２５％ＲＨでの表面電気抵抗は１０^９Ωであった。また、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。尚、各層塗布液については、塗布後の付量で組成を示した。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。
【０１９６】
《下引き塗布液ａ−１》；（ポリ塩化ビニリデン無し）
ＳＢＲポリマーラテックス
スチレン／ブタジエン／ヒドロキシエチルメタクリレート／ジビニルベンゼ
ン＝６７／３０／２．５／０．５（質量％） １６０質量部
２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジン ４質量部
マット剤（ポリスチレン，平均粒径２．４μｍ） ３質量部
《下引き塗布液ａ−２》；（ポリ塩化ビニリデン有り）
ＰＶｄＣポリマーラテックス
コア部９０質量％、シェル部１０質量％のコアシェルタイプのラテックス
コア部：塩化ビニリデン／メチルアクリレート／メチルメタクリレート／アクリロニトリル／アクリル酸＝９３／３／３／０．９／０．１（質量％）
シェル部：塩化ビニリデン／メチルアクリレート／メチルメタクリレート／アクリロニトリル／アクリル酸＝８８／３／３／３／３（質量％）
（重量平均分子量３８０００） ３０００質量部
２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジン ２３質量部
マット剤（ポリスチレン，平均粒径２．４μｍ） １．５質量部
下記染料Ａ １質量部
【０１９７】
【化１】

【０１９８】
《下引き塗布液ｂ》
アルカリ処理ゼラチン
（Ｃａ^２＋含量３０ｐｐｍ、ゼリー強度２３０ｇ） ５０ｍｇ／ｍ^２
《導電層》
ジュリマーＥＴ−４１０（日本純薬（株）製）
：Ｔｇ＝５２℃ ３８ｍｇ／ｍ^２
ＳｎＯ_２／Ｓｂ（９／１質量比、平均粒子径０．２５μｍ）１２０ｍｇ／ｍ^２
マット剤（ポリメチルメタクリレート、平均粒子径５μｍ） ７ｍｇ／ｍ^２
デナコールＥＸ−６１４Ｂ（ナガセ化成工業（株）製） １３ｍｇ／ｍ^２
《中間層》
ジュリマーＥＴ−４１０（日本純薬（株）製）
：Ｔｇ＝５２℃ ３８ｍｇ／ｍ^２
《下引き塗布液ｃ−１》；（ポリ塩化ビニリデン無し）
ＳＢＲポリマーラテックス：
スチレン／ブタジエン／ヒドロキシエチルメタクリレート／ジビニルベンゼ
ン＝６７／３０／２．５／０．５（質量％） １６０質量部
２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジン ４質量部
マット剤（ポリスチレン，平均粒径２．４μｍ） ３質量部
《下引き塗布液ｃ−２》；（ポリ塩化ビニリデン有り）
ＰＶｄＣポリマーラテックス：コア部９０質量％、シェル部１０質量％
（コアシェルタイプのラテックス）
コア部：塩化ビニリデン／メチルアクリレート／メチルメタクリレート／アクリロニトリル／アクリル酸＝９３／３／３／０．９／０．１（質量％）
シェル部：塩化ビニリデン／メチルアクリレート／メチルメタクリレート／アクリロニトリル／アクリル酸＝８８／３／３／３／３（質量％）
（重量平均分子量３８０００） ３０００質量部
２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジン ２３質量部
マット剤（ポリスチレン，平均粒径２．４μｍ） １．５質量部
《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。
【０１９９】
《熱処理条件》
１．２５ｍ幅にスリットした後の支持体のＰＥＴ２およびＰＥＮ３に対し、張力２ｈＰａで１８０℃、１分間の低張力熱処理を実施した。
【０２００】
《印刷版材料１０１〜１０３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、ＰＥＴ１は１．２％、ＰＥＴ２は０．２％、ＰＥＮ３は０．２％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。
【０２０１】
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）、および表４に示す画像形成機能層塗布液を用いて下引き済み支持体の各々のＡ面上にワイヤーバーを用いて塗布した。
【０２０２】
それぞれ、下引き済み支持体上に親水性層１、親水性層２の順番でワーヤーバーを用いてそれぞれ乾燥付量が２．７ｇ／ｍ^２、０．７ｇ／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、その後、表４に示す画像形成機能層塗布液を、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。
【０２０３】
《親水性層１用塗布液の調製》
表２に記載の各素材を、ホモジナイザを用いて十分に攪拌混合した後、表２に記載の組成で混合、濾過して親水性層１用塗布液を調製した。
【０２０４】
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。
【０２０５】
【表２】

【０２０６】
《親水性層２用塗布液の調製》
表３に記載の各素材を、ホモジナイザを用いて十分に攪拌混合した後、表３に記載の組成で混合、濾過して親水性層２用塗布液を調製した。
【０２０７】
【表３】

【０２０８】
《画像形成機能層塗布液の調製》
【０２０９】
【表４】

【０２１０】
《熱変化率の測定》
ＭＤ方向（長さ方向）５ｃｍ幅×ＴＤ方向（幅方向）５０ｃｍ長にサンプルを切り出し、２３℃４８％ＲＨ下に２４時間調湿した後、４５ｃｍ間隔の孔を開け、孔の間隔をピンゲージを用い測長する（この長さをＬとする）。これを１２８℃に加熱したヒートブロックに１分接触させ無張力下で熱処理する。これを２３℃４８％ＲＨ下に２４時間調湿した後、孔の間隔をピンゲージを用い測長する（この長さをＤとする）。これから下記式に従い熱変化率Ｈを求める。
熱変化率Ｈ（％）＝１００×（Ｌ−Ｄ）／Ｌ
測定した熱変化率Ｈの絶対値を表５に示す。
【０２１１】
《印刷版材料１０１〜１０３の評価》
（ａ）赤外線レーザ方式による画像形成
上記で作製した印刷版材料１０１〜１０３の試料を、保存性の代用条件として５０℃８０％のサーモ条件で３日間保管した。その試料を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のレーザビームを用い、露光エネルギを３００ｍＪ／ｃｍ^２とした条件で、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１０１〜１０３を各々作製した。
【０２１２】
（ｂ）上記で画像形成した印刷版試料１０１〜１０３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。
【０２１３】
《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、インクとして、東洋インク社製のトーヨーキングハイエコーＭ紅を使用して印刷を行った。印刷開始のシークエンスはＰＳ版の印刷シークエンスで行い、特別な機上現像操作は行わなかった。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。
【０２１４】
《インク着肉性の評価》
１０００枚印刷後に、インクの供給を止めて水のみ５分間供給した。その後インクの供給を再開しインクを着肉させて何枚目に正常なインク濃度になる印刷物が得られるかを評価した。枚数が少ないほどインク着肉性が優れている。
【０２１５】
《寸法安定性の評価》
印刷前に版面に５０μｍ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（寸法変化（μｍ））測定した。変化が少ないほど優れている。
【０２１６】
《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２万枚まで行った）。印刷枚数の多いほど優れている。
【０２１７】
以上により得られた結果を表５に示す。
【０２１８】
【表５】

【０２１９】
表５から、比較の試料と比べて、本発明の印刷版試料は、インク着肉性、寸法安定性が良好であり、且つ、耐刷性にも優れていることが明らかである。
【０２２０】
実施例２
《印刷版材料２０１の作製》
実施例１で作製した印刷版材料１０２と同様にして画像形成機能層を塗布した。さらに画像形成機能層の上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。
【０２２１】
《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２
０万 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。
【０２２２】
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）。
【０２２３】
以上により得られた結果を表６に示す。
【０２２４】
【表６】

【０２２５】
表６から、オーバーコート層を設けた本発明の印刷版材料２０１は、インク着肉性、スクラッチ耐性が良好であり、かつ耐刷性に優れていることが明らかである。
【０２２６】
【発明の効果】
寸法安定性がよく、複数の版を用いて印刷する場合に色ズレが起こりにくく、刷り出し時のインク着肉性や耐刷性のよいプラスチックフィルム支持体を用いた印刷版材料が得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing plate material having an image forming function by heat and a printing method using the same.
[0002]
[Prior art]
In recent years, with the digitization of print data, a computer-to-plate (CTP) technique that is inexpensive, easy to handle, and has the same printability as a PS plate has been demanded. In particular, expectations for a so-called processless CTP printing plate, which does not require a developer treatment with a special agent to reduce the burden on the global environment, are increasing.
[0003]
One of the most prominent image forming methods for processless printing plates is infrared laser recording, which can be broadly divided into three types of recording methods: ablation type, heat-fused image layer on-machine development type, and hot-melt transfer type, which will be described later. Exists.
[0004]
Infrared laser recording makes it possible to record a high-resolution image in a short time, but has a problem that the price of an exposure system is high.
[0005]
Examples of the ablation type include those described in Patent Documents 1 to 5 below. These are, for example, those having a hydrophilic layer and a lipophilic layer on a support, and laminating any of them as a surface layer.
[0006]
If the surface layer is a hydrophilic layer, an image portion can be formed by exposing the lipophilic layer by exposing the hydrophilic layer to an image and exposing the lipophilic layer by ablating the hydrophilic layer. However, since contamination of the inside of the exposure apparatus due to the scattered matter of the ablated surface layer becomes a problem, a water-soluble protective layer is further provided on the hydrophilic layer to prevent the ablated surface layer from scattering and the protective layer on the printing machine. At the same time, a method of removing the ablated surface layer has been proposed.
[0007]
The heat-fused image layer is an on-machine development type in which an image forming layer containing thermoplastic fine particles is used on a support, an image is formed by exposure and heating with a high-output infrared laser, and then developed. There is known a so-called processless printing plate technology in which printing can be performed by removing unnecessary portions by applying ink and dampening solution on a printing press without performing chemical treatment such as a liquid (Patent Document 6 and Patent Document 6). 7).
[0008]
In addition, as a hot-melt transfer type, for example, a hot-melt material such as DICOweb of Man Roland Co., Ltd. is used instead of an aluminum grain, and a hot-melt material is image-likely transferred to a metal sleeve having a reusable hydrophilic surface. After the transfer, a method of fixing the image by heating is used.
[0009]
On the other hand, a metal plate such as aluminum has conventionally been used as a support for a CTP printing plate material. Recently, however, a printing plate technology using a plastic film support has been known to facilitate handling and carrying of the printing plate. I was able to. Techniques described in Patent Documents 8 and 9 are also known as on-press development types.
[0010]
However, processless printing plates using these plastic supports have poor dimensional stability such as color misregistration when printing a large number of sheets using a plurality of plates as in color printing, and have printability, especially printing. The performance was insufficient for ink deposition and printing durability at the time of dispensing.
[0011]
[Patent Document 1]
Japanese Patent Publication No. Hei 8-507727
[0012]
[Patent Document 2]
JP-A-6-186750
[0013]
[Patent Document 3]
JP-A-6-199064
[0014]
[Patent Document 4]
JP-A-7-314934
[0015]
[Patent Document 5]
JP-A-10-244773
[0016]
[Patent Document 6]
JP-A-9-12387
[0017]
[Patent Document 7]
JP-A-9-123388
[0018]
[Patent Document 8]
JP 2002-79772 A
[0019]
[Patent Document 9]
JP 2002-79773 A
[0020]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to reduce the occurrence of color misregistration when printing a large number of sheets using a plurality of printing plates such as color printing, and to improve printability, especially ink inking property and printing durability at the time of printing. It is to obtain a printing plate material using a plastic film support.
[0021]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following means.
[0022]
1. In a printing plate material having an image forming functional layer containing at least one layer of heat-fusible fine particles or heat-fusible fine particles on one surface of a plastic film support, an absolute value of a heat change rate H represented by the following formula: Is not more than 0.05%.
[0023]
H (%) = 100 × (LD) / L
L: Length of printing plate material when conditioned at 23 ° C. and 48% RH for 1 day
D: Length of printing plate material when heat-treated at 128 ° C for 1 minute and then conditioned for 1 day at 23 ° C and 48% RH
2. The printing according to the above item 1, wherein the plastic film support is heat-treated after stretching and heat setting, where Tg is the glass transition temperature of the plastic film, and Tg + 50 to Tg + 150 ° C. Plate material.
[0024]
3. 3. The printing plate material as described in 1 or 2 above, further comprising at least one hydrophilic layer between the plastic film support and the image layer forming functional layer.
[0025]
4. 4. The printing plate material as described in any one of the above items 1 to 3, wherein the average thickness of the plastic film support is in the range of 150 μm to 300 μm.
[0026]
5. The printing plate material as described in any one of the above items 1 to 4, wherein at least one of the hydrophilic layers has a porous structure.
[0027]
6. The printing plate material as described in any one of the above items 1 to 5, wherein any one layer on the plastic film support contains a light-to-heat conversion material.
[0028]
7. The printing plate material as described in any one of the above items 1 to 6, wherein at least one surface of the plastic film support has at least one layer containing a polyvinylidene chloride resin.
[0029]
8. 8. The printing plate material as described in any one of 1 to 7 above, wherein the water content of the plastic film support is 0.5% by mass or less.
[0030]
9. 9. A printing method, comprising: after forming an image on the printing plate material according to any one of 1 to 8 above using a thermal head or a thermal laser, removing a non-image portion of the image forming functional layer on a printing press. .
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the absolute value of the heat change rate H of the printing plate material needs to be 0.05% or less, preferably 0.04% or less, and more preferably 0.03% or less.
[0032]
The thermal change rate (H) of the printing plate material is obtained by the following equation.
H (%) = 100 × (LD) / L
put it here,
L: Length of printing plate material when conditioned at 23 ° C. and 48% RH for 1 day
D: length of the printing plate material when heat-treated at 128 ° C. for 1 minute and then conditioned for 1 day at 23 ° C. and 48% RH;
It is.
[0033]
The following method is preferable to keep the thermal change rate H of the printing plate material in the above range, and it is more preferable to combine the following methods.
[0034]
(1) The moisture content of the support is 0.5% by mass or less
(2) The support has been heat-treated in a temperature range of Tg + 50 to Tg + 150 ° C., where Tg is the glass transition temperature of the plastic film after stretching and heat setting.
Here, the moisture content of the support is D 'represented by the following formula.
[0035]
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 water content 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.
[0036]
Means for controlling the moisture content of the support to 0.5% by mass or less include (1) heat-treating the support at 100 ° C. or higher immediately before applying the coating solution for the image forming functional layer and other layers; And (3) controlling the relative humidity in the step of applying the coating liquid for the image forming functional layer and other layers, and (3) heat treating the support at 100 ° C. or higher before applying the coating liquid for the image forming functional layer and other layers. Then, cover and store with a moisture-proof sheet, and apply immediately after opening. These may be performed in combination of two or more.
[0037]
<Heat treatment>
The heat treatment of the plastic film after stretching and heat setting in the present invention will be described. The stretching and the heat setting will be described later. The heat treatment according to the present invention is preferably achieved by the following means after cooling, winding and then unwinding in a separate step after the completion of heat setting. 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. In addition, it is preferable to use a single transport method or a combination of a plurality of transport methods in which the film hangs down under its own weight and is wound downward. 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.
[0038]
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.
[0039]
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 the temperature range of Tg (glass transition temperature) of the plastic film +50 to Tg + 150 ° C., 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 500 kPa. The processing time is preferably from 30 seconds to 30 minutes, and more preferably from 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 heat treatment, and fine scratches due to friction with the transport roll and the like. Can also be suppressed.
[0040]
In the present invention, the heat treatment is required at least once in order to obtain a desired dimensional change rate, and can be performed two or more times as necessary.
[0041]
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.
[0042]
In the present invention, the heat treatment is preferably performed after applying the undercoat layer. 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.
[0043]
<Plastic film support>
The plastic film support according to the printing plate material of the present invention will be described.
[0044]
(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.
[0045]
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 phthalate (E120 = 160 kg / mm)²), Polycarbonate (E120 = 170 kg / mm²), 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.
[0046]
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.
[0047]
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 150 μm to 300 μm, and the thickness distribution is preferably 10% or less.
[0048]
The average thickness of the support is preferably in the range of 150 μm to 300 μm as described above, more preferably in the range of 160 μm to 280 μm, and particularly preferably in the range of 170 μm to 250 μm.
[0049]
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, more preferably 8% or less, It is particularly preferably at most 6%.
[0050]
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 36 points is measured, and the average value and the maximum value are measured. Find the value and minimum value.
[0051]
(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.
[0052]
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 with a sintering filter or the like, extruded from a T-die, and then glass transition temperature (Tg) −50. An unstretched sheet is formed on a casting drum controlled at a temperature of from C to Tg. At this time, it is preferable to use an electrostatic application method or the like to make the thickness distribution fall within the above range.
[0053]
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.
[0054]
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.
[0055]
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.
[0056]
(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.
[0057]
As the undercoat layer, it is preferable to provide a layer containing gelatin or latex on the support. Also, conductive layers such as the conductive polymer-containing layer described in JP-A-7-20596 [0031] to [0073] and the metal oxide-containing layer described in JP-A-7-20596 [0074] to [0081] Is preferably provided. The conductive layer may be coated on any side as long as it is on the plastic film support, but is preferably coated on the side opposite to the image forming functional layer with respect to the support. 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.
[0058]
In the present invention, a plastic film support is used, and a plastic film and a material (also referred to as a composite substrate) such as a metal plate (for example, iron, stainless steel, aluminum, etc.) or paper coated with polyethylene are appropriately attached. Combined composite supports can also be used. 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.
[0059]
(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.
[0060]
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, polyvinyl alcohol described in Swiss Patent No. 330,158, etc., polystyrene or polymethacrylate described in US Pat. No. 3,079,257, polyacrylonitrile described in US 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.
[0061]
(Polyvinylidene chloride resin)
In one embodiment for obtaining the effects described in the present invention, the printing plate material of the present invention is characterized in that the support is a plastic film as described above, and one surface of the support having an image forming functional layer. However, there is an embodiment having at least one layer containing a polyvinylidene chloride resin.
[0062]
As the polyvinylidene chloride resin according to the present invention, a copolymer is preferred, and the amount of the vinylidene chloride monomer polymerization component in the repeating units of the copolymer is preferably 70 to 99.9% by mass, and further, It is preferably from 85 to 99% by mass, particularly preferably from 90 to 99% by mass.
[0063]
The copolymerization components other than the vinylidene chloride monomer in the copolymer include methacrylic acid, acrylic acid, itaconic acid, citraconic acid and esters thereof, acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, Glycidyl methacrylate, 2-hydroxyethyl methacrylate, vinyl acetate, acrylamide, styrene and the like can be mentioned.
[0064]
The weight average molecular weight of these copolymers is preferably in the range of 5,000 to 100,000, more preferably 8,000 to 80,000, and particularly preferably 10,000 to 45,000. Here, the weight average molecular weight can be measured by a commercially available GPC (gel permeation chromatography) device.
[0065]
The arrangement of the monomer units of these copolymers is not limited, and may be any of random, block, and the like.
[0066]
When the polyvinylidene chloride resin is an aqueous dispersion, it may be a latex of polymer particles having a uniform structure or a latex of so-called core-shell structure polymer particles having different compositions in a core portion and a shell portion. Specific examples of the vinylidene chloride copolymer include the following. However, the numerical value indicating the copolymerization ratio is a mass ratio, and Mw indicates a weight average molecular weight.
[0067]
(A) Latex of vinylidene chloride: methyl acrylate: acrylic acid (90: 9: 1) (Mw = 42000)
(B) Latex of vinylidene chloride: methyl acrylate: methyl methacrylate: acrylonitrile: methacrylic acid (87: 4: 4: 4: 1) (Mw = 40000)
(C) Latex of vinylidene chloride: methyl methacrylate: glycidyl methacrylate: methacrylic acid (90: 6: 2: 2) (Mw = 38000)
(D) Latex of vinylidene chloride: ethyl methacrylate: 2-hydroxyethyl methacrylate: acrylic acid (90: 8: 1.5: 0.5) (Mw = 44000)
(E) Core-shell type latex (core 90% by mass, shell 10% by mass)
Core: vinylidene chloride: methyl acrylate: methyl methacrylate: acrylonitrile: acrylic acid (93: 3: 3: 0.9: 0.1)
Shell part: vinylidene chloride: methyl acrylate: methyl methacrylate: acrylonitrile: acrylic acid (88: 3: 3: 3: 3) (Mw = 38000)
(F) Core-shell type latex (core 70% by mass, shell 30% by mass)
Core: vinylidene chloride: methyl acrylate: methyl methacrylate: acrylonitrile: methacrylic acid (92.5: 3: 3: 1: 0.5)
Shell part: vinylidene chloride: methyl acrylate: methyl methacrylate: acrylonitrile: methacrylic acid (90: 3: 3: 1: 3) (Mw = 20,000)
(Polyvinylidene chloride containing layer)
The polyvinylidene chloride resin according to the present invention may be any of an undercoat layer, a hydrophilic layer described later, an image forming function layer, and other layers as long as the image forming function layer is coated on the support. , But is preferably contained in an undercoat layer. The undercoat layer may be a single layer or a plurality of layers. The thickness of these layers is preferably provided on at least one side of the support with a thickness in the range of 0.5 to 10 μm, and more preferably, on both sides of the support, layers having a thickness of 0.8 to 5 μm each. It is particularly preferable that both sides have a thickness of 1.0 to 3 μm.
[0068]
<Image forming functional layer>
The image forming functional layer according to the invention preferably contains heat-fusible and / or heat-fusible fine particles. Specifically, the following materials can be contained.
[0069]
(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.
[0070]
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, linolenamide, 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.
[0071]
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.
[0072]
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.
[0073]
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.
[0074]
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.
[0075]
(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.
[0076]
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.
[0077]
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.
[0078]
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 size 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 coated on 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.
[0079]
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.
[0080]
The content of the thermoplastic fine particles in the constituent layer is preferably from 1 to 90% by mass of the entire layer, more preferably from 5 to 80% by mass.
[0081]
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.
[0082]
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.
[0083]
(Water-soluble material)
The image forming functional layer containing the heat-fusible and / or heat-fusible fine particles according to the invention may further contain a water-soluble material. By containing the water-soluble material, when the image-forming functional layer in the unexposed portion is removed using a fountain solution or ink on a printing press, the removability can be improved.
[0084]
As the water-soluble material, the water-soluble resin mentioned as a material that can be contained in the hydrophilic layer can also be used, but as the image forming functional layer of the present invention, it is preferable to use a saccharide, and particularly to use an oligosaccharide. Is preferred. 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 with 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.
[0085]
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.
[0086]
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.
[0087]
[Table 1]

[0088]
In the present invention, since it is preferable that the layer containing the saccharide is formed by coating with an aqueous solution, when formed from an aqueous solution, when the oligosaccharide present in the layer is an oligosaccharide that forms a hydrate, The melting point is considered to be the melting point of the hydrate. 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 in a temperature range in which the hot-melted fine particles are fused, and a porous structure of the hot-melted fine particles is obtained. It does not hinder image formation such as melt infiltration into the hydrophilic layer or fusion of heat-fused fine particles.
[0089]
Among the oligosaccharides, trehalose, which is in a relatively high purity state, is industrially available at low cost and has a very low hygroscopicity, despite its high solubility in water, and has on-press developability and storage. Both sexes are very good.
[0090]
Also, when the oligosaccharide hydrate is heat-melted to remove the water of hydration and solidified (for a short time after solidification), the crystals of the anhydride are formed, but trehalose has a higher melting point than the hydrate. It is characteristic that the temperature is higher than 100 ° C. This means that the portion exposed to heat is melted by infrared exposure, and immediately after re-solidification, the exposed portion has a high melting point and is hardly melted. This has the effect of making image defects such as banding less likely to occur at the time of exposure. To achieve the object of the present invention, trehalose is particularly preferred among the oligosaccharides.
[0091]
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.
[0092]
Further, the image forming functional layer according to the present invention preferably contains a light-to-heat conversion material described later.
[0093]
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.
[0094]
<Hydrophilic layer>
The hydrophilic layer according to the present invention will be described. Here, 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.
[0095]
As described in claim 5, 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.
[0096]
(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.
[0097]
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.
[0098]
(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.
[0099]
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.
[0100]
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.
[0101]
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".
[0102]
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, the use of alkaline “Snowtex PS-S”, “Snowtex PS-M”, and “Snowtex PS-L” improves the strength of the hydrophilic layer and increases the number of printed sheets. However, the occurrence of background dirt is suppressed, which is particularly preferable.
[0103]
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.
[0104]
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) ".
[0105]
The colloidal silica having an average particle size 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.
[0106]
The ratio of colloidal silica / necklace-shaped colloidal silica having an average particle size of 20 nm or less is preferably in the range of 95/5 to 5/95, more preferably 70/30 to 20/80, and more preferably 60/40. The range of 30 to 70/70 is more preferable.
[0107]
(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.
[0108]
(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 deposited 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.
[0109]
The porous aluminosilicate particles are produced, for example, by the 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.
[0110]
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. When the particle size is large, the particles themselves become very brittle, and the durability of the coating film is reduced. Conversely, if the pore volume is less than 0.5 ml / g, the printing performance may be slightly insufficient.
[0111]
(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.
[0112]
(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:
[0113]
(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.
[0114]
As the zeolite particles used in the present invention, a synthetic zeolite having a stable Al / Si ratio and a relatively sharp particle size distribution is preferable. 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;
[0115]
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.
[0116]
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 polysilicic acid. 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.
[0117]
Further, the above layered mineral intercalation compounds (eg, pillared crystals), 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.
[0118]
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.
[0119]
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.
[0120]
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 Na 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, in order to prevent the dissolution of the inorganic particles.
[0121]
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.
[0122]
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. And a resin such as an acrylic polymer latex, a vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone. As the water-soluble resin used in the present invention, it is preferable to use a polysaccharide.
[0123]
As the polysaccharide, starches, celluloses, polyuronic acid, pullulan and the like can be used, and particularly, cellulose derivatives such as methylcellulose salts, carboxymethylcellulose salts, and hydroxyethylcellulose salts are preferable, and sodium salts and ammonium salts of carboxymethylcellulose are preferable. 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.
[0124]
It is preferable that the surface of the hydrophilic layer has an uneven structure with 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 coating solution for the hydrophilic layer. When the hydrophilic layer is applied and dried by forming a phase separation when the hydrophilic layer is applied, a structure having better printability can be obtained, which is preferable.
[0125]
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.
[0126]
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, a cationic resin may be further contained. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or 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.
[0127]
Further, 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, etc., 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).
[0128]
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.
[0129]
Further, a light-to-heat conversion material described below can be contained. In the case of a particulate material, the light-to-heat conversion material preferably has a particle size of less than 1 μm.
[0130]
(Inorganic particles having a particle size of 1 μm or more or particles coated with an inorganic material)
As the inorganic particles that can be used in the present invention, for example, known metal oxide particles such as silica, alumina, titania, and zirconia can be used, but in order to suppress sedimentation in the coating solution, a porous material is used. It is preferable to use fine metal oxide particles. As the porous metal oxide particles, the aforementioned porous silica particles and porous aluminosilicate particles can be preferably used.
[0131]
Examples of the particles coated with an inorganic material include particles in which organic particles such as polymethyl methacrylate and polystyrene are used as a core material and coated with inorganic particles having a smaller particle size than the core material particles. The particle size of the inorganic particles is preferably about 1/10 to 1/100 of the core material particles. As the inorganic particles, similarly, known metal oxide particles such as silica, alumina, titania, and zirconia can be used. As the coating method, various known methods can be used.However, the core material particles and the coating material particles collide with each other at high speed in the air such as a hybridizer to dig the coating material particles into the surface of the core material particles. A dry coating method of fixing and coating can be preferably used.
[0132]
Further, particles obtained by plating a core material of organic particles with metal can also be used. Examples of such particles include “Micropearl AU” manufactured by Sekisui Chemical Co., Ltd., in which resin particles are plated with gold.
[0133]
The particle size is preferably from 1 to 10 μm, more preferably from 1.5 to 8 μm, and particularly preferably from 2 to 6 μm.
[0134]
In the present invention, the amount of particles having a particle size of 1 μm or more is preferably 1 to 50% by mass, more preferably 5 to 40% by mass of the entire hydrophilic layer. For the entire hydrophilic layer, a low content ratio of a carbon-containing material such as an organic resin or carbon black is preferable for improving hydrophilicity, and the total of these materials is preferably less than 9% by mass. And more preferably less than 5% by mass.
[0135]
<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.
[0136]
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.
[0137]
In the present invention, the hydrophilic overcoat layer can contain a light-to-heat conversion material described below.
[0138]
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.
[0139]
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 US Pat. No. 3,079,257, US Pat. No. 3,022,169. Examples thereof include polycarbonates described in the specification and the like.
[0140]
The added amount of these matting agents is 1 m²It is preferably 0.1 g or more and less than 10 g.
[0141]
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, monoglyceride stearate, 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.
[0142]
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.
[0143]
<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.
[0144]
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.
[0145]
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.
[0146]
As graphite, 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.
[0147]
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, 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.
[0148]
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 oxides 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.
[0149]
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.
[0150]
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.
[0151]
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.
[0152]
<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 an exposed portion or an unexposed portion be changed by light or heat by exposure.
[0153]
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.
[0154]
In the present invention, the photoacid generator means a compound that generates a Lewis acid or a Bronsted acid upon exposure.
[0155]
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.
[0156]
Examples of the diazo compound include diazonium salts disclosed in U.S. Pat. Nos. 2,063,631 and 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.
[0157]
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.
[0158]
As the polyhalogen compound, acetophenone containing polyhalogen, for example, tribromoacetophenone, trichloroacetophenone, o-nitro-tribromoacetophenone, p-nitro-tribromoacetophenone, m-nitro-tribromoacetophenone, 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.
[0159]
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.
[0160]
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.
[0161]
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.
[0162]
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.
[0163]
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. .
[0164]
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.
[0165]
In addition, an organic dye such as an arylamine can be used as a 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.
[0166]
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 p'-tetramethylaminodiphenyl-4-anilinonaphthylmethane, p, p ', p "-triaminophenylmethane, p, p', p" -hexapropyltriaminotriphenylmethane and the like.
[0167]
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, acidic clay clay kaolin, inorganic acids such as zeolite, aromatic carboxylic acids, anhydrides 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 Preference is given to methylolates and salts of phenolic compounds (hereinafter also including complex salts, unless otherwise specified).
[0168]
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.
[0169]
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.
[0170]
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.
[0171]
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.
[0172]
<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 the handling. 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.
[0173]
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; polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG) and polyvinyl ether (PVE), which are resins having an ether bond. 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.
[0174]
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.
[0175]
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. .
[0176]
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.
[0177]
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.
[0178]
The added amount of these matting agents is 1 m²It is preferably 0.1 g or more and less than 10 g.
[0179]
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 of the matting agent, the amount added and the amount of the binder. It is preferable that If the thickness is less than 0.1 μm, there is a concern that there is a problem 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 manufacturing or other reasons. 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.
[0180]
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.
[0181]
<exposure>
The present invention also provides a printing method including a step of forming an image on a printing plate material using a thermal head or a thermal laser, and then removing a non-image portion of the image forming layer on a printing machine.
[0182]
Since the image formation of the printing plate material of the present invention can be performed by heat, it is possible to form an image by a thermal head used in a thermal printer, but it is particularly preferable to perform image formation by exposure with a thermal laser. .
[0183]
Regarding the exposure according to the present invention, more specifically, scanning exposure using a laser that emits light in the infrared and / or near-infrared region, that is, emits light in a wavelength range of 700 to 1500 nm is preferable. 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.
[0184]
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. Good.
[0185]
In general,
(1) a method in which the printing plate material held by the plate-shaped holding mechanism is subjected to two-dimensional scanning using one or a plurality of laser beams to expose the entire printing plate material,
(2) On the printing plate material held along the cylindrical surface inside the fixed cylindrical holding mechanism, using one or a plurality of laser beams from inside the cylinder, the circumferential direction of the cylinder (main scanning direction) ), While moving in the direction perpendicular to the circumferential direction (sub-scanning direction) while scanning, the entire surface of the printing plate material is exposed,
(3) A printing plate material held on the surface of a cylindrical drum that rotates around an axis as a rotating body is rotated in the circumferential direction (main scanning direction) by rotating the drum using one or more laser beams from outside the cylinder. ), While moving in a direction perpendicular to the circumferential direction (sub-scanning direction), and exposing the entire surface of the printing plate material.
[0186]
In the present invention, the scanning exposure method (3) is particularly preferable, and the exposure method (3) is particularly used in an apparatus that performs exposure on a printing apparatus.
[0187]
The printing plate material on which an image has been formed in this way can be 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 is supplied 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.
[0188]
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.
[0189]
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 a general external drum method (method (3)) using a thermal laser, it generally takes about 3 minutes from the start to the end of exposure, so that the image intensity differs between the exposure start part and the end part at the end of exposure. There are concerns. By providing the drying step, the difference in image intensity can be reduced to a level that does not cause any problem.
[0190]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0191]
Example 1
<< Preparation of support >>: Preparation of polyester film
(Polyethylene terephthalate 1; PET1)
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 stretching temperature was longitudinally stretched 1.0 times at 102 ° C. in the former stretching and 4.1 times at 110 ° C. in the latter stretching. Then, it was transversely stretched 6 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. After slitting the chuck portion of the tenter, knurling was performed on both ends, and after cooling to 40 ° C., winding was performed at 83.4 N / m. The width (film formation width) of the PET film thus obtained was 2.5 m.
[0192]
(Polyethylene terephthalate 2; PET2)
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 stretching temperature was longitudinally stretched 1.3 times at 102 ° C. in the first stage stretching and 2.6 times at 110 ° C. in the second stage 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 4.8 kg / m. The width (film formation width) of the PET film thus obtained was 2.5 m.
[0193]
(Polyethylene-2,6-naphthalate; PEN3)
PEN having an IV (intrinsic viscosity) = 0.55 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) using methyl 2,6-naphthalenedicarboxylate and ethylene glycol according to a conventional method. Was. This was pelletized, dried at 150 ° C. for 4 hours, melted at 310 ° C., extruded from a T-die, and rapidly cooled on a cooling drum at 80 ° C. to produce an unstretched film. This was longitudinally stretched by 1.2 times at 132 ° C. in the first stage stretching and 2.7 times by 140 ° C. in the second stage stretching. Then, the film was transversely stretched 4.0 times at 145 ° C. with a tenter. After that, it was heat-set at 250 ° C. for 20 seconds and relaxed 4% in the horizontal direction at the same temperature. After slitting the chuck portion of the tenter, knurling was performed on both ends, and after cooling to 40 ° C., winding was performed at 4.8 kg / m. The width (film forming width) of the PEN film thus obtained was 2.5 m. The average film thickness (μm) of PEN3 was 190 μm.
[0194]
《Preparation of undercoated support》
8 W / m on both sides of each of the PET1, 2 and PEN3 films obtained above.²Min of corona discharge treatment, and then, as shown in Table 5, after applying the following undercoating coating solution a-1 or a-2 on one surface to a dry film thickness of 0.8 μm, The undercoating coating solution b was applied and dried at 180 ° C. for 4 minutes (undercoating surface A).
[0195]
Further, the following conductive layer and intermediate layer were sequentially coated on the opposite surface and dried at 180 ° C. for 4 minutes, and the following undercoating coating solution c-1 or c-2 was coated on these layers with a dry film thickness of 0.8 μm. And dried at 180 ° C. for 4 minutes (undercoating surface B). The surface electric resistance at 25 ° C. and 25% RH after application is 10⁹Ω. When the surface roughness of the surface on the side of the undercoating surface B was measured, the Ra value was 0.8 μm. The composition of each layer coating solution was indicated by the amount after application. Next, the surface of each undercoat layer was subjected to plasma processing under the following plasma processing conditions.
[0196]
<< Undercoating coating liquid a-1 >>; (no polyvinylidene chloride)
SBR polymer latex
Styrene / butadiene / hydroxyethyl methacrylate / divinylbenze
= 67/30 / 2.5 / 0.5 (mass%) 160 parts by mass
2,4-dichloro-6-hydroxy-s-triazine 4 parts by mass
Matting agent (polystyrene, average particle size 2.4 μm) 3 parts by mass
<< Undercoating coating liquid a-2 >>; (with polyvinylidene chloride)
PVdC polymer latex
Core-shell type latex with 90% by weight core and 10% by weight shell
Core part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 93/3/3 / 0.9 / 0.1 (% by mass)
Shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 88/3/3/3/3 (% by mass)
(Weight average molecular weight 38000) 3000 parts by mass
2,4-dichloro-6-hydroxy-s-triazine 23 parts by mass
Matting agent (polystyrene, average particle size 2.4 μm) 1.5 parts by mass
1 part by mass of the following dye A
[0197]
Embedded image

[0198]
<< Undercoating coating solution b >>
Alkali treated gelatin
(Ca²⁺Content: 30 ppm, jelly strength: 230 g) 50 mg / m²
《Conductive layer》
Julimar ET-410 (manufactured by Nippon Pure Chemical Co., Ltd.)
: Tg = 52 ° C. 38 mg / m²
SnO₂/ Sb (9/1 mass ratio, average particle size 0.25 μm) 120 mg / m²
Matting agent (polymethyl methacrylate, average particle size 5 μm) 7 mg / m²
Denacol EX-614B (manufactured by Nagase Kasei Kogyo Co., Ltd.) 13 mg / m²
《Intermediate layer》
Julimar ET-410 (manufactured by Nippon Pure Chemical Co., Ltd.)
: Tg = 52 ° C. 38 mg / m²
<< Undercoating solution c-1 >>; (no polyvinylidene chloride)
SBR polymer latex:
Styrene / butadiene / hydroxyethyl methacrylate / divinylbenze
= 67/30 / 2.5 / 0.5 (mass%) 160 parts by mass
2,4-dichloro-6-hydroxy-s-triazine 4 parts by mass
Matting agent (polystyrene, average particle size 2.4 μm) 3 parts by mass
<< Undercoating coating liquid c-2 >>; (with polyvinylidene chloride)
PVdC polymer latex: 90% by mass of core portion, 10% by mass of shell portion
(Core-shell type latex)
Core part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 93/3/3 / 0.9 / 0.1 (% by mass)
Shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 88/3/3/3/3 (% by mass)
(Weight average molecular weight 38000) 3000 parts by mass
2,4-dichloro-6-hydroxy-s-triazine 23 parts by mass
Matting agent (polystyrene, average particle size 2.4 μm) 1.5 parts by mass
《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.
[0199]
《Heat treatment conditions》
The PET 2 and PEN 3 of the support after slitting to a width of 1.25 m were subjected to a low tension heat treatment at 180 ° C. for 1 minute at a tension of 2 hPa.
[0200]
<< Preparation of printing plate materials 101-103 >>
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. When a part of the support sample was sampled and the water content was measured, PET1 was 1.2%, PET2 was 0.2%, and PEN3 was 0.2%. With respect to those covered, the sheet was removed and immediately applied.
[0201]
Coating solution for hydrophilic layer 1 shown in Table 2 (preparation method is shown below), coating solution for hydrophilic layer 2 shown in Table 3 (preparation method is shown below), and image forming functional layer shown in Table 4 The solution was applied on each side A of the undercoated support using a wire bar.
[0202]
Each of the hydrophilic layer 1 and the hydrophilic layer 2 was dried on the undercoated support in the order of hydrophilic layer 1 and hydrophilic layer 2 by using a wire bar at 2.7 g / m 2.²0.7g / m²And dried at 120 ° C. for 3 minutes, and then subjected to a heat treatment at 60 ° C. for 24 hours. Thereafter, the coating amount of the image forming functional layer shown in Table 4 was dried using a wire bar to obtain 0.6g / m²After drying at 50 ° C. for 3 minutes, a seasoning treatment was performed at 50 ° C. for 72 hours.
[0203]
<< Preparation of coating liquid for hydrophilic layer 1 >>
Each material shown in Table 2 was sufficiently stirred and mixed using a homogenizer, and then mixed with the composition shown in Table 2 and filtered to prepare a coating solution for the hydrophilic layer 1.
[0204]
The details of each material are as follows, and the numerical values in the table represent parts by mass.
[0205]
[Table 2]

[0206]
<< Preparation of coating liquid for hydrophilic layer 2 >>
Each material shown in Table 3 was sufficiently stirred and mixed using a homogenizer, and then mixed with the composition shown in Table 3 and filtered to prepare a coating solution for the hydrophilic layer 2.
[0207]
[Table 3]

[0208]
<< Preparation of coating solution for image forming functional layer >>
[0209]
[Table 4]

[0210]
《Measurement of thermal change rate》
A sample was cut out in a length of 5 cm in the MD direction (length direction) × a length of 50 cm in the TD direction (width direction) and conditioned at 23 ° C. and 48% RH for 24 hours. The length is measured (this length is L). This is brought into contact with a heat block heated to 128 ° C. for 1 minute and heat-treated under no tension. After this was conditioned at 23 ° C. and 48% RH for 24 hours, the distance between the holes was measured using a pin gauge (this length is referred to as D). From this, the thermal change rate H is determined according to the following equation.
Thermal change rate H (%) = 100 × (LD) / L
Table 5 shows the absolute values of the measured thermal change rates H.
[0211]
<< Evaluation of printing plate materials 101-103 >>
(A) Image formation by infrared laser method
The samples of the printing plate materials 101 to 103 produced as described above were stored for 3 days under a thermocondition of 50 ° C. and 80% as a condition for preservation. The sample was wound around an exposure drum and fixed. 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 300 mJ / cm.²An image was formed with 175 lines at 2400 dpi (dpi represents the number of dots per 2.54 cm.), And printing plate samples 101 to 103 were produced.
[0212]
(B) The printing plate samples 101 to 103 on which the images were formed were evaluated for various properties as printing plates by the following printing method.
[0213]
《Printing method》
As a printing device, DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd. was used. A coated paper, a 2% by mass solution of Astromark 3 (manufactured by Niken Kagaku Kenkyusho) as dampening solution, and Toyo manufactured by Toyo Ink Co., Ltd. as ink were used. Printing was performed using King Hi Echo M Beni. The printing start sequence was a PS plate printing sequence, and no special on-press development operation was performed. When the plate surface was observed after printing, the non-image portion of the material according to the present invention was removed.
[0214]
<< Evaluation of ink inking property >>
After printing 1000 sheets, the supply of ink was stopped and only water was supplied for 5 minutes. After that, the supply of the ink was restarted, and the ink was deposited to evaluate the number of sheets on which a print having a normal ink density was obtained. The smaller the number of sheets, the better the ink inking property.
[0215]
《Evaluation of dimensional stability》
Before printing, scratches having a width of 50 μm were made at two places 50 cm apart from the plate surface. The change (dimension change (μm)) of the distance between the two flaws on the printing paper after printing 100 sheets and the printing paper after printing 3000 sheets was measured. The smaller the change, the better.
[0216]
《Evaluation of printing durability》
The number of printed sheets where half or more of the 3% halftone dot image was missing was obtained (printing was performed up to 20,000 sheets). The higher the number of prints, the better.
[0217]
Table 5 shows the results obtained as described above.
[0218]
[Table 5]

[0219]
From Table 5, it is clear that the printing plate sample of the present invention has better ink inking property and dimensional stability, and is more excellent in printing durability than the comparative sample.
[0220]
Example 2
<< Preparation of printing plate material 201 >>
An image forming functional layer was applied in the same manner as in the printing plate material 102 prepared in Example 1. Further, the following overcoat layer was dried on the image forming functional layer using a wire bar to a dry weight of 0.4 g / m.²And dried at 50 ° C. for 3 minutes. Further, on the opposite side of the image forming functional layer, the following back layer was dried at 1.5 g / m 2 using a wire bar.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.
[0221]
<< 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 2)
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.
[0222]
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).
[0223]
Table 6 shows the results obtained as described above.
[0224]
[Table 6]

[0225]
From Table 6, it is clear that the printing plate material 201 of the present invention provided with the overcoat layer has good ink inking property, scratch resistance, and excellent printing durability.
[0226]
【The invention's effect】
A printing plate material using a plastic film support that has good dimensional stability, is unlikely to cause color misregistration when printing using a plurality of plates, and has good ink inking properties and printing durability at the start of printing.

Claims (9)

In a printing plate material having an image forming functional layer containing at least one layer of heat-fusible fine particles or heat-fusible fine particles on one surface of a plastic film support, an absolute value of a heat change rate H represented by the following formula: Is not more than 0.05%.
H (%) = 100 × (LD) / L
L: Length of the printing plate material when conditioned at 23 ° C. and 48% RH for 1 day D: Length of the printing plate material when heat treated at 128 ° C. for 1 minute and conditioned at 23 ° C. and 48% RH for 1 day Sa 2. The plastic film support according to claim 1, wherein the plastic film support is heat-treated after stretching and heat-setting, when the glass transition temperature of the plastic film is Tg, in a temperature range of Tg + 50 to Tg + 150 ° C. 3. Printing plate material. 3. The printing plate material according to claim 1, further comprising at least one hydrophilic layer between the plastic film support and the image layer forming functional layer. The printing plate material according to any one of claims 1 to 3, wherein the average thickness of the plastic film support is in a range of 150 µm to 300 µm. The printing plate material according to any one of claims 1 to 4, 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 film support contains a light-to-heat conversion material. The printing plate material according to any one of claims 1 to 6, wherein at least one surface of the plastic film support has at least one layer containing a polyvinylidene chloride resin. The printing plate material according to any one of claims 1 to 7, wherein the water content of the plastic film support is 0.5% by mass or less. A printing method comprising: after forming an image on the printing plate material according to any one of claims 1 to 8 using a thermal head or a thermal laser, removing a non-image portion of the image forming functional layer on a printing press. Method.