JP4182713B2 - Printing plate material - Google Patents

Description

以上に蒸留水を加えて１０００ｍｌとし、塗布液とした。
【０１２３】
（第二下塗り層）
上記フィルムの第一下塗り層を形成した面にコロナ放電処理を施した後、下記組成の塗布液を、３５℃、相対湿度２２％の雰囲気下でエアーナイフ方式により乾燥後の膜厚が０．１μｍとなるように塗布した。その後、１４０℃で２分間乾燥を行った。
【０１２４】
〈第二下塗り層組成〉
ゼラチン ９．６ｇ
界面活性剤（Ａ） ０．４ｇ
硬膜剤（ｂ） ０．１ｇ
以上に蒸留水を加えて１０００ｍｌとし、塗布液とした。
【０１２５】
【化１】

【０１２６】
（基材２）
厚さ０．２４ｍｍのアルミニウム板（材質１０５０、調質Ｈ１６）を、５０℃の１質量％水酸化ナトリウム水溶液中に浸漬し、溶解量が２ｇ／ｍ²になるように溶解処理を行い水洗した後、２５℃の０．１質量％塩酸水溶液中に３０秒間浸漬し、中和処理した後水洗した。
【０１２７】
次いでこのアルミニウム板を、塩酸１０ｇ／Ｌ、アルミを０．５ｇ／Ｌ含有する電解液により、正弦波の交流を用いて、ピーク電流密度が５０Ａ／ｄｍ²の条件で電解粗面化処理を行なった。この際の電極と試料表面との距離は１０ｍｍとした。電解粗面化処理は１２回に分割して行い、一回の処理電気量（陽極時）を４０Ｃ／ｄｍ²とし、合計で４８０Ｃ／ｄｍ²の処理電気量（陽極時）とした。また、各回の粗面化処理の間に５秒間の休止時間を設けた。
【０１２８】
電解粗面化後は、５０℃に保たれた１質量％水酸化ナトリウム水溶液中に浸漬して、粗面化された面のスマット含めた溶解量が２ｇ／ｍ²になるようにエッチングし、水洗し、次いで２５℃に保たれた１０％硫酸水溶液中に１０秒間浸漬し、中和処理した後水洗した。次いで、２０％硫酸水溶液中で、２０Ｖの定電圧条件で電気量が１５０Ｃ／ｄｍ²となるように陽極酸化処理を行い、さらに水洗した。
【０１２９】
次いで、水洗後の表面水をスクイーズした後、７０℃に保たれた１質量％の３号ケイ酸ソーダ水溶液に３０秒間浸漬し、水洗を行った後に８０℃で５分間乾燥し、基材２を得た。基材２のＲａは４５０ｎｍであった（ＷＹＫＯ社製ＲＳＴ Ｐｌｕｓを使用し、４０倍で測定した）。
【０１３０】
（基材３）
電解粗面化処理及びその後のエッチング処理を行わずに陽極酸化処理を行った以外は基材２と同様にして、基材３を得た。同様にＲａは２２０ｎｍであった。〔金属被覆粒子（ａ）の作製〕
（金属被覆粒子（ａ）−１）
コア粒子として、シリコーン樹脂（ポリメチルシルセスキオキサン）微粒子であるトスパール１２０Ａ（ＧＥ東芝シリコーン社製、平均粒径２μｍ）を用いた。
【０１３１】
コア粒子をアミン錯塩系アルカリキャタリスト：ＯＰＣ−５０インリューサ（奥野製薬社製）液に、液を攪拌しながら添加して分散した。次いでジメチルアミノボランを添加して、２５℃で３分間還元した。これを濾過、洗浄してから下記組成の無電解メッキ浴（１）中で６５℃でメッキを行い、浸漬時間を調整することで、平均０．２μｍ厚のＳｎ−Ｂｉ合金被覆層を形成した。次いで、これを濾過、洗浄し、さらにアルコールで洗浄した後に乾燥して金属被覆粒子（ａ）−１を得た。
【０１３２】
［無電解メッキ浴（１）組成］
メタンスルホン酸第一スズ（Ｓｎ²⁺として） ４０ｇ／Ｌ
メタンスルホン酸ビスマス（Ｂｉ³⁺として） ３ｇ／Ｌ
メタンスルホン酸 ８０ｇ／Ｌ
チオ尿素 １２０ｇ／Ｌ
エチレンジアミンテトラメチレンリン酸 ３０ｇ／Ｌ
次亜リン酸 ３０ｇ／Ｌ
（金属被覆粒子（ａ）−２）
コア粒子として、トスパール１４５Ａ（ＧＥ東芝シリコーン社製、平均粒径４．５μｍ）を用いた以外は粒子（ａ）−１と同様にして、金属被覆粒子（ａ）−２を得た。
【０１３３】
（金属被覆粒子（ａ）−３）
コア粒子としてカーボンブラックで黒色に着色したアクリルコポリマー微粒子：ラブコロール０２０（３Ｍ）ブラック（平均粒径３μｍ、大日精化社製）を用いた。
【０１３４】
特開２００１−２４７９７４号の実施例１に記載された方法に従って、粒子表面を処理し、パラジウム触媒を吸着させて表面を活性化させた。
【０１３５】
次いで、無電解メッキ浴（１）を用いて粒子（ａ）−１と同様にして平均０．２μｍ厚のＳｎ−Ｂｉ合金被覆層を形成した。次いで、これを濾過、洗浄し、さらにアルコールで洗浄した後に乾燥して金属被覆粒子（ａ）−３を得た。
【０１３６】
（金属被覆粒子（ａ）−４）
特開平１１−３２９０６０号の実施例２に記載された方法に従って、平均粒径３μｍのジビニルベンゼン共重合体粒子に定法の無電解メッキにより０．１５μｍ厚のＮｉメッキを行い、次いで置換メッキによってＡｕの厚さが６０ｎｍの粒子を得た。
【０１３７】
次いで、無電解メッキ浴（１）を用いて粒子（ａ）−１と同様にして平均０．２μｍ厚のＳｎ−Ｂｉ合金被覆層を形成した。次いで、これを濾過、洗浄し、さらにアルコールで洗浄した後に乾燥して金属被覆粒子（ａ）−４を得た。
【０１３８】
〔塗布液の作製〕
〈層（Ａ）の塗布液の作製〉
表１の組成の素材を十分に攪拌混合した後、濾過して層（Ａ）−１〜４の塗布液を作製した。（表中、単位記載のない数値は質量部を示す、以下同）
【０１３９】
【表１】

【０１４０】
〈親水性層塗布液の作製〉
表２の組成の素材をホモジナイザを用いて十分に攪拌混合した後、濾過して親水性層の塗布液を作製した。
【０１４１】
【表２】

【０１４２】
〈保護層用塗布液の作製〉
表３の組成を十分に混合攪拌した後、濾過して保護層用塗布液を作製した。
【０１４３】
【表３】

【０１４４】
（感熱記録材料の作製）
表４に示した基材と塗布液との組み合わせ層（Ａ）を、ワイヤーバーで表に示した乾燥付量となるように塗布して、参考例の感熱記録材料を作製した。
【０１４５】
層（Ａ）の乾燥条件は８０℃３分間で行い、次いで６０℃２４時間のエイジングを行った。
【０１４６】
（画像形成）
画像形成は赤外線レーザー露光により行った。露光には波長８３０ｎｍ、スポット径約１８μｍのレーザービームを用い、レーザービームの焦点を印刷版材料表面に合わせて、露光エネルギーを１５０ｍＪ／ｃｍ²から５０ｍＪ刻みで６００ｍＪ／ｃｍ²とさせた各条件で、２４００ｄｐｉ（尚、ｄｐｉとは２．５４ｃｍ当たりのドット数を表す。）、１７５線で画像を形成した。評価用の画像として、ベタ画像と１〜９９％の網点画像を用いた。
【０１４７】
（露光可視画性の評価）
露光済の材料の露光可視画性の程度を目視で評価し、結果を表４に示した。尚、表中の記号は下記の評価結果を示している。
【０１４８】
◎：非常に明瞭な画像が得られている
○：明瞭な画像が得られている
△：画像の確認は可能である
×：画像を確認しにくい
（感度評価）
露光可視画性が得られているサンプルをルーペで評価し、適正露光エネルギーを評価した。適正露光エネルギーは５０％網点のスクエアドットがほぼ５０％の網点面積となっている露光エネルギーとし、結果を表４に示した。
【０１４９】
（露光装置汚染評価）
赤外線露光時にサンプル表面を厚さ１２μｍのＰＥＴフィルムでカバーし、ペットフィルムへの付着物の有無、着色の程度を評価した。結果を表４に示した。
【０１５０】
尚、表中の記号は下記の評価結果を示している。
◎：実質的に付着物なし
○：わずかに白色の付着物あり
△：白色の付着物あり
×：着色した付着物あり
【０１５１】
【表４】

【０１５２】
表４より、参考例の感熱記録材料は露光装置汚染を生じることなく、低露光エネルギーで画像形成が可能であることがわかる。
【０１５３】
実施例２
（印刷版材料の作製）
表５に示した基材と塗布液との組み合わせで、各層をワイヤーバーで表に示した乾燥付量となるように塗布して実施例の印刷版材料を作製した。
【０１５４】
層（Ａ）及び親水性層の乾燥条件は１００℃３分間で行い、次いで６０℃２４時間のエイジングを行った。
【０１５５】
保護層はエイジング後に塗布形成し、乾燥条件は６０℃３分間で行った。
（比較印刷版材料の作製）
基材２に表６に示した組成のインク着肉層を乾燥付量が０．７ｇ／ｍ²となるように塗布し、１００℃で３分間乾燥した。次いで、特開平１１−２６８４１８号の実施例１記載の方法に従ってビスマス分散液を作製した。このビスマス分散液をインク着肉層の上にビスマス量が平均して０．２μｍ厚となるように塗布し、１００℃で３分間乾燥し、ビスマス層を形成した。しかしながら、インク着肉層表面は基材２の表面粗さに由来する凸凹を有しているため、ビスマス層は表面の凹部では厚く、凸部では薄く形成されていた。
【０１５６】
次いで、この上に前記親水性層を乾燥付量が０．５ｇ／ｍ²となるように塗布し、１００℃で３分間乾燥した。これを６０℃２４時間のエイジングを行って、比較例の印刷版材料を得た。
【０１５７】
（画像形成）
画像形成は赤外線レーザー露光により行った。露光には波長８３０ｎｍ、スポット径約１８μｍのレーザービームを用い、レーザービームの焦点を印刷版材料表面に合わせて、露光エネルギーを１５０ｍＪ／ｃｍ²から５０ｍＪ刻みで６００ｍＪ／ｃｍ²とさせた各条件で、２４００ｄｐｉ、１７５線で画像を形成した。評価用の画像として、ベタ画像と１〜９９％の網点画像を用いた。
【０１５８】
（露光可視画性の評価）
露光済の印刷版材料の露光可視画性の程度を目視で評価し、結果を表５に示した。なお、表中の記号は下記の評価結果を示している。
【０１５９】
◎：非常に明瞭な画像が得られている
○：明瞭な画像が得られている
△：画像の確認は可能である
×：画像を確認しにくい
（印刷方法）
印刷機：三菱重工業（株）製ＤＡＩＹＡ１Ｆ−１の版胴に印刷版材料を取り付け、コート紙、湿し水：アストロマーク３（日研化学研究所製）２質量％、インク（東洋インク（株）製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。印刷は５万枚まで行った。
【０１６０】
（刷り出し性評価）
刷り出し時、良好なＳ／Ｎ（非画像部に地汚れがなく、かつ、画像部網点画像が良好に再現され、ベタ濃度が適正範囲となっている）を有した印刷物が得られるまでの印刷枚数を評価した。結果を表５に示した。なお、表中の記号は下記の評価結果を示している。また、印刷物に画像が得られなかったサンプルについては画像なしと表記した。
【０１６１】
◎：１０枚未満
○：１０枚以上２０枚未満
△：２０枚以上４０枚未満
×：４０枚以上
（感度評価）
印刷された紙面上の画像をルーペで評価し、適正露光エネルギーを評価した。適正露光エネルギーは５０％網点のスクエアドットがほぼ５０％の網点面積となっている露光エネルギーとし、結果を表５に示した。
【０１６２】
（スクラッチ汚れ耐性評価）
印刷版材料サンプルの非画像部に印刷前にＨＥＩＤＯＮ試験機を用いて荷重を変化させてスクラッチ跡をつけておき、印刷開始から１００枚目の時点でどの荷重までが汚れとなっていないかを評価した。触針には０．３ｍｍφのサファイア針を用いた。結果を表５に示した。なお、表中の記号は下記の評価結果を示している。
【０１６３】
◎：１５０ｇ以上
○：１００ｇ以上１５０ｇ未満
△：５０ｇ以上１００ｇ未満
×：５０ｇ未満
（耐刷性評価：画像部）
上記感度評価で適性露光エネルギーとした露光エネルギーで形成された画像部の３％の網点が１／５程度欠落した段階で耐刷枚数とし、結果を表５に示した。
【０１６４】
（耐刷性評価：非画像部）
非画像部に地汚れが生じた段階で耐刷枚数とし、結果を表５に示した。
【０１６５】
【表５】

【０１６６】
【表６】

【０１６７】
表５から、本発明の印刷版材料は、アルミ基材を用いた場合でも感度低下が少なく、高感度な印刷版材料になっていることがわかる。これは、金属被覆粒子（ａ）のコア粒子として用いている樹脂粒子が断熱効果を発現していることによるものであると考えられる。また、露光可視画性を有するにもかかわらず装置汚染の懸念がなく、また、良好な刷り出し性と十分な耐刷性を有していることがわかる。
【０１６８】
また、本発明の態様のひとつである親水性層を設けた本発明２−２、２−５においては、刷り込みによる非画像部の汚れ発生も抑制されて、さらに良好な耐刷性が得られている。また、もうひとつの態様である保護層を有する本発明２−１〜２−４では、汎用ＣＴＰとしても十分に良好な取扱い性を有していることがわかる。
【０１６９】
一方、比較例の印刷版材料も画像形成から印刷評価までを上記実施例と同様にして行った。その結果、露光による可視画性は得られたが、ビスマス層の膜厚ムラに起因する画像形成ムラが観察された。印刷を行っても同様に画質の低い印刷物しか得られず、本発明の印刷版材料に比較し明らかに劣っていた。
【０１７０】
【発明の効果】
本発明により、高感度で、かつ露光装置汚染がなく、良好な刷り出し性と十分な耐刷性を有する印刷版材料を提供することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing plate material, and more particularly to a printing plate material capable of image formation by a computer-to-plate (CTP) method.
[0003]
[Prior art]
With the digitization of print data, there is a need for CTPs that are inexpensive, easy to handle, and have the same printability as PS plates. In particular, a general-purpose thermal processless plate that can be applied to a printing press with a direct imaging (DI) function and that has the same usability as a PS plate, and that does not require a special chemical development process in recent years. Expectations are growing.
[0004]
As a thermal processless plate for DI, for example, Thermo Lite manufactured by Agfa Co., Ltd. is mentioned. However, on-machine development operation is necessary, and printing performance when printing is started in the same printing machine sequence as the PS plate is It is insufficient. In addition, scratch resistance of the printing plate (scratched parts become printing stains) is low, and sufficient consideration is required for handling. Furthermore, the plate inspection property after exposure with a thermal laser is not particularly taken into consideration, and therefore has almost no visible exposure.
[0005]
On the other hand, a general-purpose processless plate requires a printability that can be printed without changing the printing conditions of the PS plate (without the need for on-machine development operations, of course). In addition, it is scratch stain resistance in handling within the range of common sense and visible image properties after image recording.
[0006]
In CTP, it is expected that the work of plate inspection will not be performed in the future, but it is still necessary in the current workflow. Therefore, in the thermal processless plate, after image recording Visibility, particularly exposure visibility when using a thermal laser, is one of the important performances.
[0007]
A thermal laser recording system having a wavelength of near infrared to infrared is mainly used for image formation of a thermal processless plate. Thermal processless plates that can form images by this method are roughly classified into an ablation type and a thermal fusion image layer on-machine development type, which will be described later.
[0008]
Examples of the ablation type include those described in JP-A-8-507727, JP-A-6-186750, JP-A-6-199064, JP-A-7-314934, JP-A-10-58636, and JP-A-10-244773. Can be mentioned.
[0009]
In these, for example, a hydrophilic layer and a lipophilic layer are laminated on a base material with either layer as a surface layer. If the surface layer is a hydrophilic layer, the image portion can be formed by exposing like an image, ablating the hydrophilic layer and removing it like an image, and exposing the lipophilic layer. JP-A-7-314934 discloses the use of a high melting point titanium or titanium alloy layer that absorbs infrared rays and ablate between a hydrophilic layer and a lipophilic layer.
[0010]
However, since contamination inside the exposure apparatus due to the scattered material on 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 together with the protective layer on the printing press. A method for removing the ablated surface layer has also been proposed.
[0011]
In the case of the ablation type, improving printing durability is related to increasing the strength of the surface layer, and improving printing durability leads to a decrease in sensitivity and resolution. However, it is very difficult to improve printing durability.
[0012]
Moreover, although it is possible to give exposure visible image quality by making the hues of the surface layer and the layer below it different, it is necessary to completely ablate and remove the surface layer. This can be achieved, for example, by installing a cleaner that sucks and removes the ablation scattered matter in the exposure apparatus, but it is not preferable because the cost of the apparatus increases significantly.
[0013]
In the type provided with the protective layer as described above, since the ablation scattered matter remains, even if the surface layer and the layer below it have different hues, good exposure and visible image quality cannot be obtained.
[0014]
As a means for solving the above, a method of “containing 20% by mass or more of a cyanine-based infrared-absorbing dye whose optical density can be changed by exposure in a hydrophilic overcoat layer removable on a printing press” is disclosed. (For example, refer to Patent Document 1). Although this method can surely provide good exposure visibility, it can contain a large amount of dye in the layer to be removed on the printing press, and the dye can be further developed or faded by exposure. Since either the exposed part or the unexposed part is a layer having a high color density, it is clear that contamination of the printing press due to on-press development is unavoidable.
[0015]
On the other hand, as the development type on the heat fusion image layer machine, one using a thermoplastic layer and a water-soluble binder as an image forming layer on a hydrophilic layer or an aluminum grain is disclosed (for example, patent) Reference 2). The above-mentioned Thermo Lite made by Agfa is a processless plate of this type.
[0016]
In order to improve printing durability with this type, for example, as disclosed in JP-A-9-171250, the image forming layer contains a cross-linking agent that cross-links a water-soluble binder, whereby an image area is formed. A method for improving the strength of the steel can be considered. However, such a method deteriorates the on-press developability, that is, the printing performance, and is not preferable even if the printing durability is improved. Thus, it is very difficult to achieve both printing performance and printing durability with an on-press development type printing plate material.
[0017]
Further, for imparting exposure visible image properties, for example, those utilizing the exposure fading of infrared absorbing dyes as described in JP-A No. 11-240270 can be mentioned, and such dyes are added to the image forming layer. In this case, increasing the color difference between the unexposed area and the exposed area to improve the exposure visible image quality, that is, increasing the color density of the unexposed area, and the printing machine during on-machine development of the unexposed area. Contamination is a problem.
[0018]
As described above, with the conventional technology, it has been very difficult to impart sufficient printability, printing durability, and exposure visible image quality to the processless plate.
[0019]
[Patent Document 1]
JP 2002-205466 A
[0020]
[Patent Document 2]
US Pat. No. 2,938,397
[0021]
[Problems to be solved by the invention]
  An object of the present invention is to provide a printing plate material having sufficient printability, printing durability, and exposure visible image property as a general-purpose processless plate.
[0022]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitution.
[0023]
  1. A layer (A) containing particles (a) in which a core of nonmetallic particles is coated with a metal or alloy layer on a substrate.And a metal or alloy layer covering the particles (a) is composed of a plurality of layers, and at least one of the metal or alloy layers has a melting point of 300 ° C. or less, and has gold, copper inside thereof. Having a layer of metal or alloy containing any one of nickelA printing plate material characterized by that.
[0024]
  2.2. The printing plate material as described in 1 above, wherein the metal or alloy that coats the particles (a) does not contain lead.
[0025]
  3.3. The printing plate material as described in 1 or 2 above, wherein the nonmetallic particles that are the core of the particles (a) are ink-thinning properties.
[0026]
  4).The layer (A) containing the particles (a) is a layer in which the particles (a) are dispersed in a hydrophilic matrix insoluble in water. The printing plate material described.
[0027]
  5.5. The printing plate material as described in any one of 1 to 4 above, which has a hydrophilic layer (B) on the layer (A) containing the particles (a).
[0028]
  6).6. The printing plate material as described in any one of 1 to 5 above, wherein the outermost layer has a protective layer containing a water-soluble material.
[0029]
  7.7. The printing plate material according to any one of 1 to 6, wherein at least one layer on the substrate contains a photothermal conversion material.
[0035]
Hereinafter, the present invention will be described in detail.
The printing plate material of the present invention is a printing plate material having a layer (A) containing particles (a) obtained by coating a core of nonmetallic particles with a metal or an alloy on a substrate.
The printing plate material of the present invention is preferably imaged by infrared laser exposure, and the ultrathin layer metal that covers the particles (a) in the exposed area is melted by heat, and the molten metal is subjected to its own surface tension. By reducing the specific surface area, the surface of the core particles of the particles (a) (or the surface immediately below the metal layer thermally melted by exposure) is exposed to form an image. In this embodiment, it is preferable that the ultrathin layer metal covering the particles (a) has a photothermal conversion function.
[0036]
Examples of the metal-coated particles that can be used in the present invention include JP-A-9-204815, JP-A-9-306231, JP-A-9-306232, JP-A-11-329060, WO98 / 46811, and JP-A-2001-126532. It can be produced by forming a metal coating layer on the core particles by electroless plating by the method described in Kai 2001-247974.
[0037]
The metal-coated particles thus prepared can be further coated with a hydrophilic material to form particles having a hydrophilic surface. As the hydrophilic material, a hydrophilic binder, a cross-linking agent and the like described later can be used.
[0038]
As a particle size of particle | grains (a), it is preferable that it is 0.1-20 micrometers, and it is more preferable that it is 0.5-10 micrometers. It may have a particle size distribution within a preferred range, or a plurality of types of particles having different average particle sizes may be used in combination.
[0039]
If it is 0.1 μm or less, there is a concern that the exposure of the core particle surface due to the exposure described above may be insufficient, and if it is larger than 20 μm, the resolution is lowered, or the surface of the layer (A) has a surface roughness more than necessary. It becomes undesirable to have.
[0040]
As content of the particle | grains (a) in a layer (A), it is preferable that it is 30-99 mass% of the whole layer, and it is more preferable that it is 50-90 mass%. If it is less than 30% by mass, image formation is insufficient, and if it exceeds 99% by mass, it is difficult to maintain the strength of the layer (A).
[0041]
The preferred range for the thickness (average value) of the layer (A) varies depending on the average particle size of the particles (a), but is preferably in the range of ± 50% of the average particle size, and in the range of ± 30%. More preferably. This means that it is preferable that the particles (a) are arranged in a single layer in the layer (A), that is, the particles (a) do not exist in the thickness direction (the ratio is low even if they exist). Means.
[0042]
In addition to the particles (a), the layer (A) can contain a hydrophilic binder, a crosslinking agent, a photothermal conversion material, a surfactant and the like which will be described later. That is, the layer (A) is preferably a layer in which the particles (a) are dispersed in a hydrophilic matrix insoluble in water.
[0043]
In the layer (A), since the unexposed part becomes a non-image part, the surface of the particle (a) is hydrophilic or the surface of the particle (a) is insoluble in water. It is preferable to have a hydrophilic surface by coating with.
[0044]
Even in a mode in which the hydrophilic binder covers the surface of the particle (a), the metal layer on the surface of the particle (a) is melted and moved by exposure, and a void is formed below the hydrophilic binder on the surface of the exposed portion. As a result, the hydrophilic binder can be removed by a normal printing process using dampening water or ink on the printing press, that is, it can be developed on the press.
[0045]
In order to obtain good on-press developability, the hydrophilic binder covering the surface of the particles (a) preferably has a thickness of 2.0 μm or less, and preferably 0.01 to 1.0 μm. Is more preferable. If the thickness is less than 0.01 μm, there is a concern that the non-image area may be soiled when printed.
[0046]
  According to the present inventionThe melting point of the metal or alloy covering the particles (a) is 300 ° C. or lower.But thisAmong such materials, examples of the simple metal include In (156.2 ° C.), Sn (232 ° C.), and Bi (274.1 ° C.).
[0047]
Such a low-melting-point metal or alloy coating layer can also be formed by plating. Specific methods include JP-A Nos. 11-1791, 11-21673, 11-61426, 2000-26991, 2000-87252, 2001-164396, and 2001-172791. Can be mentioned. Among these, the electroless plating method is preferable.
[0048]
Moreover, as one of the preferable aspects of the printing plate material of this invention, the aspect in which the metal or alloy which coat | covers particle | grains (a) does not contain lead is mentioned. This is because it is preferable as an environmental measure.
[0049]
Furthermore, as a preferred embodiment of the printing plate material of the present invention, it is mentioned that the nonmetallic particles that are the core of the particles (a) are ink-inking properties. For this, resin particles such as polymethyl methacrylate, styrene, and acrylic that are generally used as a matting agent can be preferably used. In addition, inorganic particles having a surface treated to impart ink depositability can also be used. A known silane coupling agent or the like can be used for the treatment.
[0050]
  In the printing plate material of the present invention, the metal or alloy covering the particles (a) is composed of a plurality of layers.is there.This is because, when forming a metal or alloy layer on the surface layer side, when another metal layer is formed as a base treatment, the adhesion strength of the layer is improved or productivity is improved. Can be done.
[0051]
As one of the embodiments, the metal or alloy that coats the particles (a) is composed of a plurality of layers, and one of the coating layers is a metal or alloy layer having a melting point of 300 ° C. or less, with gold inside thereof, The aspect which has the layer of the metal or alloy containing either copper and nickel can be mentioned. In the case of this aspect, when the metal or alloy layer having a melting point of 300 ° C. or less melts, the surface of the inner metal or alloy layer containing gold, copper, or nickel is exposed to form an image. Is done. A metal or alloy layer containing any one of gold, copper, and nickel has ink deposition properties and can be preferably used as an image portion of a printing plate.
[0052]
As particles having gold plating or the like on the surface, known conductive fine particles can also be used. For example, “Micropearl AU” series manufactured by Sekisui Fine Chemical Co., Ltd. has resin particles plated with gold. Using this particle as a core, a metal or alloy layer having a melting point of the present invention of 300 ° C. or lower is further formed on the surface, whereby the particle (a) of this embodiment can be produced. In this case, since the core particles themselves have conductivity, it is possible to apply a method by electrolytic plating.
[0053]
Another embodiment of the present invention includes an embodiment having a hydrophilic layer (B) on the layer (A). By providing the hydrophilic layer (B), it is possible to improve printability and to improve printing durability by suppressing the occurrence of background stains in non-image areas when imprinted. Since the hydrophilic layer (B) also preferably has on-press developability in the exposed area, it is preferably a thin layer of 0.01 to 2.0 μm, more preferably 0.05 to 1.0 μm. .
[0054]
For the hydrophilic layer (B), the same material as the hydrophilic matrix of the layer (A) can be used, but it is more porous than the hydrophilic matrix of the layer (A) in order to improve printability. This is a preferred embodiment.
[0055]
Furthermore, in this invention, the aspect which has a protective layer containing a water-soluble raw material in the outermost layer can also be mentioned. In this embodiment, there is an advantage that even when the plate surface is scratched by scratches or the like, the portion thereof is less likely to be stained. The protective layer itself must have on-press developability.
[0056]
In addition to the water-soluble material, a surfactant, a lubricant and the like can be contained. As the lubricant, known waxes can be used, and in particular, fatty acid amide wax can be preferably used.
[0057]
  In addition, any layer on the base material can contain a photothermal conversion material.
  Also, GroupIn the heat-sensitive recording material having a layer (A) containing particles (a) in which a core of non-metallic particles is coated with a metal or an alloy on a material, at least one of the coating layers of particles (a) has a melting point of 300. A heat-sensitive recording material which is a metal or alloy layer having a temperature of not higher than ° C. and has a different color tone between the outermost layer of particles (a) and the particle surface under the metal or alloy layer having a melting point of not higher than 300 ° C.Is also useful.
[0058]
The thermal recording material having the configuration of the present invention is not limited to a printing plate material, and can be formed by coating, has high sensitivity and high resolution, and is particularly suitable for image formation by infrared laser exposure. It is.
[0059]
As a heat-sensitive recording material using a thin metal layer, a case where a dry process such as a vapor deposition method is used is conceivable, but there is a problem that costs increase because special equipment is required. On the other hand, methods for forming a thin metal layer by coating are also disclosed in JP-A-11-263070, JP-A-11-268418, and JP-A-2000-94839, but the process is complicated and also leads to an increase in cost. .
[0060]
  Configuration of the present inventionAppliedThe heat-sensitive recording material can be produced by simply coating and forming on a substrate, and the cost is reduced because it is very simple.
[0061]
  further, GroupA method for forming an image of a heat-sensitive recording material having a layer (A) containing particles (a) obtained by coating a core of non-metallic particles with a metal or an alloy on a material, wherein at least one of the coating layers of particles (a) The layer is a metal or alloy layer having a melting point of 300 ° C. or less, and the color tone of the outermost layer of the particle (a) is different from that of the particle surface under the metal or alloy layer having a melting point of 300 ° C. or less. The heat-sensitive recording material is exposed imagewise using an infrared laser, and a layer of metal or alloy in which the melting point of the particles (a) in the exposed area is 300 ° C. or less is melted. For forming a heat-sensitive recording material by exposing the surface of the underlying particle by reducing the particle size and forming an identifiable imageIs also useful.
[0062]
  AboveIn the image forming method, since the lowest image forming temperature is relatively low at 300 ° C. or less, it is possible to increase the sensitivity, and it is possible to form an image without removing the material in the image forming layer. There is no need to add a special suction device to the exposure apparatus, and image formation can be performed without concern about apparatus contamination.
[0063]
As a material for forming the hydrophilic layer matrix, a metal oxide is preferable.
The metal oxide preferably contains metal oxide fine particles. 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 3 to 100 nm, and several kinds of metal oxide fine particles having different average particle diameters can be used in combination. Moreover, surface treatment may be performed on the particle surface.
[0064]
The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer.
[0065]
Among the above, colloidal silica can be preferably used in the present invention. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and can provide good strength.
[0066]
The colloidal silica preferably includes a necklace-shaped colloidal silica, which will be described later, and fine particle colloidal silica having an average particle size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.
[0067]
The necklace-like colloidal silica used in the present invention is a general term for an aqueous dispersion of spherical silica whose primary particle diameter is on the order of nm. The necklace-like colloidal silica used in the present invention means “pearl necklace-like” colloidal silica in which spherical colloidal silica having a primary particle diameter of 10 to 50 nm is bonded to a length of 50 to 400 nm. A pearl necklace shape (that is, a pearl necklace shape) means that an image in a state in which silica particles of colloidal silica are connected and connected has a shape like a pearl necklace. The bond 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. Specific examples of the colloidal silica in the form of necklace include “Snowtex-PS” series manufactured by Nissan Chemical Industries, Ltd.
[0068]
Product names include “Snowtex-PS-S (average particle size in the connected state is about 110 nm)”, “Snowtex-PS-M (average particle size in the connected state is about 120 nm)” and “Snowtex- PS-L (the average particle size in the connected state is about 170 nm) ", and acidic products corresponding to these are" Snowtex-PS-SO "," Snowtex-PS-MO "and “Snowtex-PS-LO”.
[0069]
By adding necklace-like colloidal silica, it becomes possible to maintain the strength while ensuring the porosity of the layer, and it can be preferably used as a porous material for the hydrophilic layer matrix.
[0070]
Among these, when “Snowtex PS-S”, “Snowtex PS-M”, and “Snowtex PS-L”, which are alkaline, are used, the strength of the hydrophilic layer is improved and the number of printed sheets is large. However, it is particularly preferable because the occurrence of soiling is suppressed.
[0071]
Further, it is known that the colloidal silica has a stronger binding force as the particle diameter is smaller, and it is preferable to use colloidal silica having an average particle diameter of 20 nm or less in the present invention, and more preferably 3 to 15 nm. preferable. Further, as described above, alkaline colloidal silica is particularly preferably used because it is highly effective in suppressing the occurrence of scumming in colloidal silica.
[0072]
Examples of alkaline colloidal silica having an average particle diameter within this range include “Snowtex-20 (particle diameter 10-20 nm)”, “Snowtex-30 (particle diameter 10-20 nm)”, “Snow” manufactured by Nissan Chemical Co., Ltd. "Tex-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- 6 nm) ".
[0073]
Colloidal silica having an average particle size of 20 nm or less is particularly preferable because it can be further improved in strength while maintaining the porous property of the layer, when used in combination with the aforementioned necklace-shaped colloidal silica.
[0074]
The ratio of colloidal silica / necklace-shaped colloidal silica having an average particle diameter of 20 nm or less is preferably 95/5 to 5/95, more preferably 70/30 to 20/80, and still more preferably 60/40 to 30/70.
[0075]
Moreover, what was disperse | distributed to the solvent as colloidal silica can be used. As such colloidal silica, “organosilica” manufactured by Nissan Chemical Co., Ltd. can be preferably used.
[0076]
As the porous material of the hydrophilic layer matrix of the present invention, porous metal oxide particles having a particle size of less than 1 μm can be contained. As the porous metal oxide particles, porous silica, porous aluminosilicate particles, or zeolite particles described later can be preferably used.
[0077]
The porous silica particles are generally produced by a wet method or a dry method. In the wet method, it can be obtained by drying and pulverizing a gel obtained by neutralizing an aqueous silicate solution, or by pulverizing a precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in porosity and particle size by adjusting the production conditions.
[0078]
As the porous silica particles, those obtained from a wet gel are particularly preferable. 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 hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. Moreover, what was manufactured as composite particle | grains of 3 or more components by adding the alkoxide of another metal at the time of manufacture can also be used for this invention. These composite particles can also control the porosity and particle size by adjusting the production conditions.
[0079]
The porosity of the particles is preferably 0.5 ml / g or more in terms of pore volume, more preferably 0.8 ml / g or more, and 1.0 to 2.5 ml / g or less. Further preferred.
[0080]
The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less smudged during printing, and the greater the water volume latitude, but greater than 2.5 ml / g. Then, the particles themselves become very brittle, and the durability of the coating film is lowered. When the pore volume is less than 0.5 ml / g, the printing performance may be slightly insufficient.
[0081]
Zeolite is a crystalline aluminosilicate and is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 to 1 nm. The general formula combining natural and synthetic zeolite is expressed as follows:
[0082]
(M₁, M₂ ^1/2)_m(Al_mSi_nO_{2 (m + n)}XH₂O
Where M₁, M₂Is an exchangeable cation, and M₁Li⁺, Na⁺, K⁺, Tl⁺, Me_FourN⁺(TMA), Et_FourN⁺(TEA), Pr_FourN⁺(TPA), C₇H₁₅N₂ ⁺, C₈H₁₆N⁺Etc., M₂Is Ca²⁺, Mg²⁺, Ba²⁺, Sr²⁺, C₈H₁₈N₂ ²⁺Etc. 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, and thus the higher the polarity and therefore the higher the hydrophilicity. A preferable Al / Si ratio is 0.4 to 1.0, and more preferably 0.8 to 1.0. x represents an integer.
[0083]
The zeolite particles used in the present invention are preferably synthetic zeolites having a stable Al / Si ratio and a relatively sharp particle size distribution, such as zeolite A: Na.₁₂(Al₁₂Si₁₂O₄₈27H₂O: Al / Si ratio 1.0, zeolite X: Na₈₆(Al₈₆Si₁₀₆O₃₈₄) ・ 264H₂O: Al / Si ratio 0.811, zeolite Y: Na₅₆(Al₅₆Si₁₃₆O₃₈₄) ・ 250H₂O; Al / Si ratio 0.412 and the like.
[0084]
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 greatly improved, it is difficult to get dirty during printing, and the water latitude is widened. Also, fingerprint marks are greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance becomes small.
[0085]
Moreover, the hydrophilic layer matrix of the printing plate material of the present invention can contain layered clay mineral particles. Examples of the layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite, and hydrotalcite, layered polysilicate. (Kanemite, macatite, ialite, magadiaite, Kenyaite, etc.). Among them, 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 charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable because it can be obtained with stable quality such as particle size. Among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.
[0086]
Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.
[0087]
As the size of the flat lamellar mineral particles, the average particle diameter (maximum length of the particles) is less than 1 μm in the state of being contained in the layer (including the case where the swelling process and the dispersion peeling process have been performed). The aspect ratio is preferably 50 or more. When the particle size is in the above-mentioned range, the continuity in the planar direction and the flexibility, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult to crack and it can be made a tough coating film in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. When the particle diameter is larger than the above range, the coating film may be non-uniform, and the strength may be locally reduced. Further, when the aspect ratio is not more than the above range, the number of tabular grains with respect to the addition amount is reduced, the viscosity is insufficient, and the effect of suppressing the sedimentation of the particulate matter is reduced.
[0088]
The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer. In particular, swellable synthetic fluorinated mica and smectite are preferable because they are effective even when added in a small amount. The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. It is preferable that the gel swollen in water is prepared and then added to the coating solution.
[0089]
A silicate aqueous solution can also be used as another additive material in the hydrophilic layer matrix of the present invention. Alkali metal silicates such as silicate Na, silicate K, and silicate Li are preferred, and their SiO₂/ M₂The O ratio is preferably selected so that the pH of the entire coating solution when the silicate is added does not exceed 13 in order to prevent dissolution of the inorganic particles.
[0090]
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 inorganic polymers or organic-inorganic hybrid polymers by the sol-gel method is described in, for example, “Application of the sol-gel method” (Sakuo Sakuo / Agne Jofusha) or cited in this book. Known methods described in the literature can be used.
[0091]
Moreover, you may contain water-soluble resin or water-dispersible resin. Examples of water-soluble resins and water-dispersible resins include polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymers, and conjugated diene systems of methyl methacrylate-butadiene copolymers. Resins such as polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylamide, and polyvinyl pyrrolidone can be mentioned. In the present invention, it is preferable to use a polysaccharide as the water-soluble resin.
[0092]
As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.
[0093]
The hydrophilic matrix used in the present invention is preferably cross-linked by a known cross-linking agent. For example, the water-soluble resin described above exists in a state where at least a part thereof is water-soluble and can be eluted in water. It is also possible to adjust the degree of crosslinking as described above. This is because even if it is a water-soluble material, when it is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity is lowered and printability may be deteriorated.
[0094]
Further, a cationic resin may be further included. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, acrylic having a tertiary amino group and a quaternary ammonium group. Examples thereof include resins and diacrylamine. The cationic resin may be added in the form of fine particles. Examples thereof include a cationic microgel described in JP-A-6-161101.
[0095]
The hydrophilic layer coating solution of the present invention may contain a water-soluble surfactant for the purpose of improving coating properties. A surfactant such as Si-based or F-based can be used, but it is particularly preferable to use a surfactant containing Si element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).
[0096]
In addition, the hydrophilic layer of the present invention can contain a phosphate. In the present invention, since the hydrophilic layer coating solution is preferably alkaline, the phosphate is preferably added as trisodium phosphate or disodium hydrogen phosphate. By adding phosphate, the effect of improving the mesh opening at the time of printing can be obtained. The addition amount of phosphate is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass as an effective amount excluding hydrate.
[0097]
The following materials can be included as photothermal conversion materials, but materials that are highly resistant to visible light, such as black pigments, are added to the layer that can be developed on-machine, and the added amount is 5% by mass of the total layer. It is preferable to set it as follows, and it is preferable that it is 0-3 mass%.
[0098]
When added to the layer (A), the hydrophilic layer (B), or the protective layer, which can be developed on the machine, it is preferable to use an infrared absorbing dye described later, and coloring with visible light among the infrared absorbing dyes It is preferable to use a dye having a small amount. As addition amount, it is 0.1-10 mass% of the whole layer, and 0.2-5 mass% is preferable.
[0099]
Examples of the pigment include carbon, graphite, metal, metal oxide and the like. As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.
[0100]
As the 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.
[0101]
As the metal, any metal can be used as long as the particle diameter is 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 spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.
[0102]
As the metal oxide, a material that is black in the visible light region or a material that is conductive or that is a semiconductor can be used.
[0103]
As the former, black iron oxide (Fe_ThreeO_Four) And black composite metal oxides containing two or more of the aforementioned metals.
[0104]
Examples of the latter include SnO doped with Sb, for example.₂(ATO), In with Sn added₂O_Three(ITO), TiO₂TiO₂And TiO (titanium oxynitride, generally titanium black) reduced. These metal oxides can also be used as a core material (BaSO_FourTiO₂, 9Al₂O_Three・ 2B₂O, K₂O · nTiO₂Etc.) can also be used. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.
[0105]
Among these photothermal conversion materials, black composite metal oxides containing two or more metals are more preferable materials.
[0106]
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 can be produced by methods disclosed in JP-A-8-27393, 9-25126, 9-237570, 9-241529, 10-231441, and the like.
[0107]
The composite metal oxide 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 the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, they have good photothermal conversion efficiency.
[0108]
These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). An average primary particle size of less than 0.01 is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.
[0109]
Infrared absorbing dyes include organic compounds such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, which are general infrared absorbing dyes , Phthalocyanine-based, naphthalocyanine-based, 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, JP-A-3-26593, Described in 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, etc. The compound of this is mentioned. These can be used alone or in combination of two or more.
[0110]
As the water-soluble material for the protective layer, the water-soluble resins mentioned as materials that can be contained in the hydrophilic layer can be used. Among these, it is preferable to use a polysaccharide.
[0111]
In addition to the above, oligosaccharides can also be used.
Since the oligosaccharide dissolves quickly in water, the protective layer on the printing device can be removed very quickly, and printing can be carried out in the same manner as a normal PS plate printing operation without being aware of the special removal operation. It can be removed by printing, and printing waste paper does not increase.
[0112]
In addition, oligosaccharides can be preferably used because they can maintain good printability without concern for reducing the hydrophilicity of the hydrophilic layer (B) or layer (A). Among oligosaccharides, trehalose is commercially available in a relatively high purity state at a low cost, and despite its high solubility in water, its hygroscopicity is very low, on-press developability, In addition, the storage stability is very good and preferable.
[0113]
As a base material, the well-known material used as a board | substrate of a printing plate can be used. For example, a metal plate, a plastic film, paper treated with a polyolefin, a composite base material obtained by appropriately bonding the above materials, and the like can be given. The thickness of the base material is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.
[0114]
Examples of the metal plate include iron, stainless steel, and aluminum, and aluminum or an aluminum alloy (hereinafter referred to as aluminum) is particularly preferable from the relationship between specific gravity and rigidity. The aluminum plate is usually used after degreasing with an alkali, an acid, a solvent or the like in order to remove oil used during rolling and winding existing on the surface. As the degreasing treatment, degreasing with an alkaline aqueous solution is particularly preferable. Moreover, in order to improve adhesiveness with a coating layer, it is preferable to perform an easily bonding process and undercoat layer application | coating to an application surface. For example, a method of dipping in a liquid containing a coupling agent such as a silicate or a silane coupling agent, or applying a liquid and then sufficiently drying may be mentioned. Anodizing treatment is also considered as a kind of easy adhesion treatment and can be used. Moreover, it can also use combining an anodizing process and the said immersion or application | coating process.
[0115]
In addition, an aluminum plate roughened by a known method and a base material combined with the above easy-adhesion treatment can also be used, and the surface is roughened by a known method and anodized, and if necessary. It is also possible to use a so-called aluminum grain having a surface treatment as a base material.
[0116]
As described above, a base material in which an anodized layer is provided on aluminum can be used as the hydrophilic layer of the present invention by appropriately performing a surface treatment on the anodized layer.
[0117]
Examples of the plastic film include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, and cellulose esters. In particular, polyethylene terephthalate and polyethylene naphthalate are preferable. These plastic films are preferably subjected to easy adhesion treatment or undercoat layer coating on the coated surface in order to improve adhesion with the coated layer. Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. Examples of the undercoat layer include a layer containing gelatin or latex.
[0118]
A substrate having a roughened surface of a plastic film can also be used.
In addition, as the composite base material, the above materials are appropriately bonded together, but may be bonded before forming the coating layer, or may be bonded after forming the coating layer, and attached to a printing press. You may paste together just before.
[0119]
【Example】
Examples of the present invention are shown below, but the embodiments of the present invention are not limited to these.
[0120]
Example 1
[Preparation of substrate]
(Substrate 1)
An undercoat layer was formed on one side of a 175 μm-thick PET film by the following procedure to obtain a substrate 1.
[0121]
(First undercoat layer)
After the corona discharge treatment is applied to the coated surface of the PET base material, a coating solution having the following composition is coated with a wire bar in an atmosphere of 20 ° C. and a relative humidity of 55% so that the film thickness after drying is 0.4 μm. did. Thereafter, drying was performed at 140 ° C. for 2 minutes.
[0122]
<First undercoat layer composition>

Distilled water was added to make 1000 ml, and a coating solution was obtained.
[0123]
(Second undercoat layer)
After the surface of the film having the first undercoat layer formed thereon is subjected to a corona discharge treatment, a coating solution having the following composition is dried by an air knife method in an atmosphere of 35 ° C. and a relative humidity of 22% so that the thickness after drying is 0 It was applied so as to be 1 μm. Thereafter, drying was performed at 140 ° C. for 2 minutes.
[0124]
<Second undercoat layer composition>
9.6 g of gelatin
Surfactant (A) 0.4g
Hardener (b) 0.1g
Distilled water was added to make 1000 ml, and a coating solution was obtained.
[0125]
[Chemical 1]

[0126]
(Substrate 2)
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 1% by mass sodium hydroxide aqueous solution at 50 ° C., and the dissolution amount was 2 g / m.²The solution was dissolved and washed with water, then immersed in a 0.1% by mass hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and then washed with water.
[0127]
Next, this aluminum plate was subjected to a peak current density of 50 A / dm by using a sine wave alternating current with an electrolyte containing hydrochloric acid 10 g / L and aluminum 0.5 g / L.²The electrolytic surface roughening treatment was performed under the conditions described above. The distance between the electrode and the sample surface at this time was 10 mm. The electrolytic surface roughening treatment is performed in 12 steps, and the amount of electricity for one treatment (at the time of anode) is 40 C / dm.²480C / dm in total²The amount of electricity to be treated (at the time of anode). In addition, a rest period of 5 seconds was provided between each surface roughening treatment.
[0128]
After electrolytic surface roughening, the amount of dissolution including the smut of the roughened surface is 2 g / m by dipping in a 1% by mass sodium hydroxide aqueous solution kept at 50 ° C.²Etching was performed, and the sample was washed with water, then immersed in a 10% sulfuric acid aqueous solution maintained at 25 ° C. for 10 seconds, neutralized, and washed with water. Next, in a 20% sulfuric acid aqueous solution, the amount of electricity is 150 C / dm2 at a constant voltage of 20 V.²Then, anodization was performed, and further washing with water was performed.
[0129]
Next, after squeezing the surface water after washing with water, it was immersed in an aqueous 1% by mass sodium silicate 3 solution maintained at 70 ° C. for 30 seconds, washed with water, dried at 80 ° C. for 5 minutes, and then the substrate 2 Got. Ra of the substrate 2 was 450 nm (measured at 40 times using RST Plus manufactured by WYKO).
[0130]
(Substrate 3)
A base material 3 was obtained in the same manner as the base material 2 except that the anodizing treatment was performed without performing the electrolytic surface roughening treatment and the subsequent etching treatment. Similarly, Ra was 220 nm. [Production of metal-coated particles (a)]
(Metal-coated particles (a) -1)
As core particles, Tospearl 120A (GE Toshiba Silicones, average particle size 2 μm), which is silicone resin (polymethylsilsesquioxane) fine particles, was used.
[0131]
The core particles were dispersed in an amine complex alkaline catalyst: OPC-50 Inleusa (Okuno Pharmaceutical Co., Ltd.) solution while stirring the solution. Dimethylaminoborane was then added and reduced at 25 ° C. for 3 minutes. This was filtered and washed, then plated at 65 ° C. in an electroless plating bath (1) having the following composition, and an immersion time was adjusted to form an Sn—Bi alloy coating layer having an average thickness of 0.2 μm. . Next, this was filtered, washed, further washed with alcohol and dried to obtain metal-coated particles (a) -1.
[0132]
[Electroless plating bath (1) Composition]
Stannous methanesulfonate (Sn²⁺As) 40g / L
Bismuth methanesulfonate (Bi³⁺As) 3g / L
Methanesulfonic acid 80g / L
Thiourea 120g / L
Ethylenediaminetetramethylene phosphate 30g / L
Hypophosphorous acid 30g / L
(Metal-coated particles (a) -2)
Metal-coated particles (a) -2 were obtained in the same manner as particles (a) -1 except that Tospearl 145A (manufactured by GE Toshiba Silicone, average particle size: 4.5 μm) was used as the core particles.
[0133]
(Metal-coated particles (a) -3)
Acrylic copolymer fine particles colored black with carbon black as core particles: Labcolol 020 (3M) black (average particle size 3 μm, manufactured by Dainichi Seika Co., Ltd.) was used.
[0134]
According to the method described in Example 1 of JP-A-2001-247974, the particle surface was treated and the surface was activated by adsorbing a palladium catalyst.
[0135]
Subsequently, an Sn—Bi alloy coating layer having an average thickness of 0.2 μm was formed in the same manner as the particles (a) -1 using the electroless plating bath (1). Next, this was filtered, washed, further washed with alcohol and dried to obtain metal-coated particles (a) -3.
[0136]
(Metal-coated particles (a) -4)
According to the method described in Example 2 of JP-A-11-329060, 0.15 μm-thick Ni plating is applied to divinylbenzene copolymer particles having an average particle diameter of 3 μm by conventional electroless plating, and then Au plating is performed by displacement plating. Particles having a thickness of 60 nm were obtained.
[0137]
Subsequently, an Sn—Bi alloy coating layer having an average thickness of 0.2 μm was formed in the same manner as the particles (a) -1 using the electroless plating bath (1). Next, this was filtered, washed, further washed with alcohol and then dried to obtain metal-coated particles (a) -4.
[0138]
[Preparation of coating solution]
<Preparation of coating solution for layer (A)>
After sufficiently stirring and mixing the materials having the compositions shown in Table 1, filtration was performed to prepare coating solutions for layers (A) -1 to 4. (In the table, numerical values without unit description indicate parts by mass, the same shall apply hereinafter)
[0139]
[Table 1]

[0140]
<Preparation of hydrophilic layer coating solution>
The material having the composition shown in Table 2 was sufficiently stirred and mixed using a homogenizer, and then filtered to prepare a coating solution for the hydrophilic layer.
[0141]
[Table 2]

[0142]
<Preparation of coating solution for protective layer>
After sufficiently mixing and stirring the compositions shown in Table 3, the mixture was filtered to prepare a protective layer coating solution.
[0143]
[Table 3]

[0144]
  (Preparation of thermal recording material)
  Apply the combination layer (A) of the base material and the coating liquid shown in Table 4 so as to be the dry weight shown in the table with a wire bar,Reference exampleA heat-sensitive recording material was prepared.
[0145]
The drying condition of the layer (A) was 80 ° C. for 3 minutes, followed by aging at 60 ° C. for 24 hours.
[0146]
(Image formation)
Image formation was performed by infrared laser exposure. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm is used. The laser beam is focused on the printing plate material surface, and the exposure energy is 150 mJ / cm.²600mJ / cm in increments of 50mJ²Under these conditions, an image was formed with 2400 dpi (dpi represents the number of dots per 2.54 cm) and 175 lines. As an image for evaluation, a solid image and a dot image of 1 to 99% were used.
[0147]
(Evaluation of exposure visibility)
The degree of exposure visible image quality of the exposed material was visually evaluated, and the results are shown in Table 4. In addition, the symbol in a table | surface has shown the following evaluation result.
[0148]
A: A very clear image is obtained.
○: A clear image is obtained
Δ: The image can be confirmed
×: Difficult to confirm image
(Sensitivity evaluation)
Samples for which the exposure visibility was obtained were evaluated with a loupe, and the appropriate exposure energy was evaluated. The appropriate exposure energy is the exposure energy at which a 50% halftone dot has a halftone dot area of about 50%, and the results are shown in Table 4.
[0149]
(Exposure device contamination assessment)
The surface of the sample was covered with a PET film having a thickness of 12 μm during infrared exposure, and the presence or absence of deposits on the pet film and the degree of coloring were evaluated. The results are shown in Table 4.
[0150]
In addition, the symbol in a table | surface has shown the following evaluation result.
◎: Substantially no deposit
○: Slightly white deposit
Δ: There is white deposit
×: There is a colored deposit
[0151]
[Table 4]

[0152]
  From Table 4,Reference exampleIt can be seen that the thermosensitive recording material can form an image with low exposure energy without causing contamination of the exposure apparatus.
[0153]
Example 2
(Preparation of printing plate material)
Each layer was coated with a combination of the base material and the coating solution shown in Table 5 so that the amount of drying shown in the table was a wire bar, and the printing plate material of the example was produced.
[0154]
The drying conditions of the layer (A) and the hydrophilic layer were 100 ° C. for 3 minutes, and then aging was performed at 60 ° C. for 24 hours.
[0155]
The protective layer was formed by coating after aging, and the drying condition was 60 ° C. for 3 minutes.
(Preparation of comparative printing plate materials)
The ink deposit layer having the composition shown in Table 6 is applied to the substrate 2 with a drying weight of 0.7 g / m.²And then dried at 100 ° C. for 3 minutes. Next, a bismuth dispersion was prepared according to the method described in Example 1 of JP-A-11-268418. This bismuth dispersion was applied onto the ink deposit layer so that the average amount of bismuth was 0.2 μm, and dried at 100 ° C. for 3 minutes to form a bismuth layer. However, since the surface of the ink deposit layer has irregularities derived from the surface roughness of the substrate 2, the bismuth layer is thick at the concave portion of the surface and thin at the convex portion.
[0156]
Next, the hydrophilic layer is dried on this with a dry weight of 0.5 g / m.²And then dried at 100 ° C. for 3 minutes. This was aged at 60 ° C. for 24 hours to obtain a printing plate material of a comparative example.
[0157]
(Image formation)
Image formation was performed by infrared laser exposure. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm is used. The laser beam is focused on the printing plate material surface, and the exposure energy is 150 mJ / cm.²600mJ / cm in increments of 50mJ²Under these conditions, an image was formed with 2400 dpi and 175 lines. As an image for evaluation, a solid image and a dot image of 1 to 99% were used.
[0158]
(Evaluation of exposure visibility)
The degree of exposure visible image quality of the exposed printing plate material was visually evaluated, and the results are shown in Table 5. In addition, the symbol in a table | surface has shown the following evaluation result.
[0159]
A: A very clear image is obtained.
○: A clear image is obtained
Δ: The image can be confirmed
×: Difficult to confirm image
(Printing method)
Printing machine: A printing plate material is attached to a plate cylinder of DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., coated paper, dampening water: 2% by mass of Astro Mark 3 (manufactured by Nikken Chemical Laboratory), ink (Toyo Ink Co., Ltd.) ) And Toyo King High Echo M Red). The printing start sequence was the PS printing sequence, and no special on-press development operation was performed. Printing was performed up to 50,000 sheets.
[0160]
(Printability evaluation)
Until printed matter having good S / N (no smudge in non-image area, halftone image in image area is reproduced well, solid density is in proper range) at the time of printing The number of printed sheets was evaluated. The results are shown in Table 5. In addition, the symbol in a table | surface has shown the following evaluation result. In addition, a sample in which no image was obtained on the printed material was described as no image.
[0161]
A: Less than 10 sheets
○: 10 or more and less than 20
Δ: 20 or more and less than 40
×: 40 or more
(Sensitivity evaluation)
The image on the printed paper was evaluated with a magnifying glass, and the proper exposure energy was evaluated. The appropriate exposure energy is the exposure energy at which the dot area of 50% halftone dots is approximately 50%, and the results are shown in Table 5.
[0162]
(Scratch dirt resistance evaluation)
Before printing, make a scratch mark by changing the load using a HEIDON tester on the non-image area of the printing plate material sample, and see what load is not soiled at the 100th sheet from the start of printing. evaluated. A 0.3 mmφ sapphire needle was used as the stylus. The results are shown in Table 5. In addition, the symbol in a table | surface has shown the following evaluation result.
[0163]
A: 150 g or more
○: 100 g or more and less than 150 g
Δ: 50 g or more and less than 100 g
X: Less than 50 g
(Evaluation of printing durability: Image part)
Table 5 shows the results of the printing durability at the stage where about 1/5 of 3% of the halftone dots of the image area formed with the exposure energy determined as the appropriate exposure energy in the sensitivity evaluation were lost.
[0164]
(Evaluation of printing durability: non-image area)
Table 5 shows the results when the number of printing durability was determined at the stage when the background smudge occurred in the non-image area.
[0165]
[Table 5]

[0166]
[Table 6]

[0167]
From Table 5, it can be seen that the printing plate material of the present invention is a highly sensitive printing plate material with little decrease in sensitivity even when an aluminum substrate is used. This is thought to be due to the fact that the resin particles used as the core particles of the metal-coated particles (a) exhibit a heat insulating effect. Further, it can be seen that there is no concern about the contamination of the apparatus despite having the exposure visible image property, and it has good printing performance and sufficient printing durability.
[0168]
In addition, in the present invention 2-2 and 2-5 provided with a hydrophilic layer which is one of the embodiments of the present invention, the occurrence of stains in the non-image area due to imprinting is also suppressed, and even better printing durability is obtained. It has been. Moreover, in this invention 2-1 to 2-4 which has a protective layer which is another aspect, it turns out that it has sufficient favorable handleability also as general purpose CTP.
[0169]
On the other hand, the printing plate material of the comparative example was subjected to the same process as the above example from image formation to printing evaluation. As a result, visible image quality by exposure was obtained, but image formation unevenness due to film thickness unevenness of the bismuth layer was observed. Even when printing was performed, only a printed matter having a low image quality was obtained, which was clearly inferior to the printing plate material of the present invention.
[0170]
【The invention's effect】
According to the present invention, it is possible to provide a printing plate material which has high sensitivity, is free from contamination of the exposure apparatus, and has good printability and sufficient printing durability.

Claims (7)

On the base material, there is a layer (A) containing particles (a) in which a core of nonmetallic particles is coated with a metal or alloy layer, and a plurality of metal or alloy layers covering the particles (a) And at least one of the metal or alloy layers has a melting point of 300 ° C. or lower and a metal or alloy layer containing any one of gold, copper, and nickel inside thereof. And printing plate material. The printing plate material according to claim 1, wherein the metal or alloy that coats the particles (a) does not contain lead. The printing plate material according to claim 1, wherein the nonmetallic particles that are the core of the particles (a) are ink-thinning properties. The layer (A) containing the particles (a) is a layer in which the particles (a) are dispersed in a hydrophilic matrix insoluble in water. The printing plate material described. The printing plate material according to claim 1, further comprising a hydrophilic layer (B) on the layer (A) containing the particles (a). The printing plate material according to any one of claims 1 to 5, further comprising a protective layer containing a water-soluble material on the outermost layer. At least 1 layer on the said base material contains a photothermal conversion raw material, The printing plate material of any one of Claims 1-6 characterized by the above-mentioned.