JP3869485B2 - Method for producing photosensitive resin plate - Google Patents

Description

【００２１】
（式１中Ｒ1、Ｒ2は水素原子、炭素数が１〜５のアルキル基、炭素数が１〜５のアルコキシル基、Ｆ、Ｃl、Ｂr、Ｉのハロゲン原子、炭素数が１〜５のヒドロキシアルキル基、炭素数が１〜５のヒドロキシアルコキシル基および４級アンモニウム塩誘導体の中から選ばれた基である。）
【００２２】
【化２】

【００２３】
（式２中Ｘ1は、水素原子、Ｆ、Ｃl、Ｂr、Ｉのハロゲン原子、炭素数１〜５のアルコキシル基、ヒドロキシル基、炭素数１〜５のアルキル基、炭素数が１〜５のヒドロキシアルキル基、炭素数が１〜５のヒドロキシアルコキシル基、の中から選ばれた基であり、Ｒ3は炭素数１〜５のアルキル基、炭素数が１〜５のヒドロキシアルキル基、炭素数１〜５のアルコキシル基、炭素数が１〜５のヒドロキシアルコキシル基、４級アンモニウム塩誘導体、
【００２４】
【化３】

【００２５】
（但しＸ2はＦ、Ｃl、Ｂr、Ｉのハロゲン原子、水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシル基、炭素数が１〜５のヒドロキシアルキル基、炭素数が１〜５のヒドロキシアルコキシル基および４級アンモニウム塩誘導体）の中から選ばれた基である。）
【００２６】
【化４】

【００２７】
（式３中Ｒ4、Ｒ5、Ｒ6は、水素原子、Ｆ、Ｃl、Ｂr、Ｉのハロゲン原子、炭素数１〜５のアルコキシル基、ヒドロキシル基、炭素数１〜５のアルキル基、炭素数が１〜５のヒドロキシアルキル基、炭素数が１〜５のヒドロキシアルコキシル基および４級アンモニウム塩誘導体の中から選ばれた基である。）
また、重合性二重結合を有する式１、式２又は式３の誘導体も本発明の水素引き抜き剤として用いることができる。
【００２８】
この様な化合物として具体的には、ベンゾフェノン、４・４’−ジメトキシベンゾフェノン、４−ヒドロキシベンゾフェノン、デオキシベンゾイン、アセトフェノン、４−メチルアセトフェノン、２−クロロアセトフェノン、アントラキノン、２−メチルアントラキノン、２−エチルアントラキノン、２，４−ジエチルチオキサントン、２−クロロチオキサントンなどを例示することができる。
また式１、式２又は式３の４級アンモニウム塩誘導体としては、（２−アクリロイルオキシ）（４−ベンゾイルベンジル）ジメチル臭化アンモニウム塩、（４−ベンゾイルベンジル）塩化トリメチルアンモニウム、２−（３−ジメチルアミノ−２−ヒドロキシプロポキシ）−３，４−ジメチル−９Ｈ−チオキサンソン−９−オンメソクロライドなどが挙げられる。
【００２９】
水素引き抜き剤を未硬化樹脂の表面層に含浸させるにはどのような方法でもかまわないが、例えば水素引き抜き剤を適当な溶剤に溶解させて得られた処理液をハケあるいはスプレーによりカバーフィルム上に塗布し、その後液状感光性樹脂を積層する方法が実用的である。また、あらかじめ水素引き抜き剤が塗布されたカバーフィルムを用いて製版してもよい。
【００３０】
上記溶剤としては水素引き抜き剤を溶解し得るものならいずれも使用できるが、該溶剤の蒸発が十分でないとレリーフ形成にムラが生じるため常温での蒸発速度が速い溶剤がより好ましい。水素引き抜き剤を溶液にして用いる場合、その濃度は溶剤１００重量部に対し多くとも２重量部であれば、表面粘着性除去効果は十分発揮される。その濃度をあまり増大させても意味はなく、むしろ露光後の未硬化樹脂を回収して再使用する場合は樹脂の感度特性を損なうことになり好ましくない。
【００３１】
後露光時に、水素引き抜き剤を含浸させた樹脂版に硬化後に照射する活性光線は、水素引き抜き剤を効率よく励起させる波長領域に波長を有していることが必要である。上述した有機カルボニル化合物を水素引き抜き剤として用いる場合、紫外線、特に３００ｎｍ以下の短波長領域に波長分布を有する紫外線を用いることが好ましい。しかし、２００ｎｍ以下に波長を有する活性光線を空気中で照射する場合、オゾンの発生、硬化物に対する酸化反応が無視できないため、２００〜３００ｎｍの波長領域に分布を有する活性光源が好ましい。そのような活性光源としては、たとえば、低圧水銀灯、殺菌灯、重水素ランプ等を挙げることができる。
【００３２】
十分な表面粘着性除去効果を得るための適正露光量は、硬化樹脂版の樹脂組成、樹脂組成に対する水素引き抜き剤の含浸量により異なるが、少なくとも５００ｍＪ／ｃｍ² (オーク製作所紫外線測定器ＵＶ−Ｍ０２により２５０ｎｍの波長における照射量を測定し、照射時間から算出した値）以上を必要とし、通常、１０００〜３０００ｍＪ／ｃｍ２の範囲で露光することが好ましい。５０００ｍＪ／ｃｍ² 以上の露光量では版表面に微少なクラックが生じるので好ましくない。
【００３３】
本発明において、水素引き抜き剤を含浸させた後、露光・現像した硬化樹脂版に対する活性光線の照射は、通常製版で行われている後露光工程と同時に行っても良いし、また別途露光工程を設けて行っても良い。すなわち通常製版の後露光工程とは、機械的強度の促進を主目的とした現像後硬化物への活性光照射であり、レリーフ露光に用いる３００ｎｍ以上の波長領域に分布を有する活性光源（例えば高圧水銀灯、超高圧水銀灯、紫外線蛍光灯、カーボンアーク灯、キセノンランプ等）と２００〜３００ｎｍの波長領域に分布を有する活性光源を併用して用いられているため、本発明の活性光線照射を通常行われている後露光工程に供して行うことが可能であり、また生産性の点で好ましい。
【００３４】
【発明の実施の形態】
以下、実施例により本発明をさらに詳細に説明する。
（印刷版表面の粘着性評価）
直径５０ｍｍ、巾１３ｍｍのアルミニウム輪の円周部表面にポリエチレンフィルムを貼り付けたものを、あらかじめ付着物を拭き取ったレリーフ表面層に接触させ、アルミニウム輪に５００ｇの荷重をかけて４秒間放置した後、毎分３０ｍｍの速度でアルミニウム輪を引き上げ、アルミニウム輪がレリーフ表面から離れる時の粘着力をプッシュブルゲージで読みとるタイプのタックテスター（東洋紡機社製）により行う。タックテスターで測定される値が小さい方が表面粘着性がない印刷版であるといえる。ただし、本粘着性評価においては、印刷時に剥がれ落ちてしまうコーティング層がない状態で、すなわち感光性樹脂組成中に表面粘着性除去を目的とした滑剤が含まれる場合は滑剤を除去して、感光性樹脂基質の粘着性を測定しなければならない。
【００３５】
タックテスターによる指示値がおよそ５０ｇを超えるものは、印刷版表面に異物が付着して印刷物に不良をきたし、また１００ｇを超えるものは、印刷版を重ね置きしたときに版同志が密着してしまったり、被印刷物が紙である場合には印刷面と紙との粘着により紙ムケの現象が起こる。良好な非粘着性印刷版としては０ｇであることが望ましいが、５０ｇ以下であれば実用上粘着性に起因する問題は起こり得ないと考えられている。印刷版の中でも特に粘着性が悪いとされている液状感光性樹脂印刷版では、表面粘着性除去の為の何らかの処置を施していない場合、タックテスターによる指示値が１００ｇを超えるものが一般的である。
【００３６】
【実施例】
液状感光性樹脂ＡＰＲ：Ｆ−４７（旭化成工業（株）製）をＡＷＦ型製版機（旭化成工業（株）製）を用いて、７ｍｍ厚の樹脂版を製版した。成形工程において、下部透明基板の上にネガフィルム、カバーフィルムを積層しカバーフィルム上に、ベンゾフェノンを２０ｇ／リットル含有するエチルアルコール溶液をハケを用いて塗布し、エチルアルコールが乾燥後、液状感光性樹脂ＡＰＲ：Ｆ−４７を積層し、その上にポリエステルベースフィルム及びマスキングフィルムを積層し、上部透明基板を載置した。２枚の基板の間はスペーサにより保持した。次いで上下透明基板より真空吸引してネガフィルム及びマスキングフィルムの密着性を保ちながら３分保持した後、上部透明基板及びマスキングフィルムを通して活性光を照射してマスキング露光を１２５秒行い、その後、下部透明基板及びネガフィルムを通して活性光を照射するレリーフ露光を１３０秒行い、マスキングフィルムを除去した。次に上部透明基板を通して活性光を照射するバック露光を２０秒行い画像形成露光を完了した。
【００３７】
このようにして露光処理した感光層を常法に従って洗浄液で洗い出し、現像した後、水道水中に現像後の版を浸せきさせ、紫外線蛍光灯（露光量２０００ｍＪ／ｃｍ² ）、殺菌灯（露光量１０００ｍＪ／ｃｍ² ）の条件で後露光を実施した。
この様にして得られた版表面の粘着性をタックテスターで測定したところ、１５ｇであり、測定後、版表面をエチルアルコールを染み込ませた布で激しく拭いて、エチルアルコールが揮発した後、版表面の粘着性をタックテスターで測定したところ、２０ｇであった。
【００３８】
【比較例】
ベンゾフェノンのエチルアルコール溶液を塗布すること以外は、すべて実施例と同様に製造された版表面の粘着性をタックテスターで測定したところ、２００ｇであり、測定後、版表面をエチルアルコールを染み込ませた布で激しく拭いて、エチルアルコールが揮発した後、版表面の粘着性をタックテスターで測定したところ、４００ｇであった。
【００３９】
【発明の効果】
本発明による感光性樹脂印刷版の製造方法では、液状感光性樹脂を用いた印刷版製版工程として挙げられる露光工程、現像工程、後露光工程、乾燥工程の一連の作業工程を増やすことがないため製版コストにかかる影響は全くない。また本発明により得られる感光性樹脂版は、印刷前後ならびに印刷中において版表面の粘着性が現れることはなく、製版を行った後、印刷中、置き版時において版表面に異物が付着することがないため版表面を拭く等の作業を行う必要がなく、その作業性はゴム版を用いる場合とほとんど変わることなく取り扱い得る。
【図面の簡単な説明】
【図１】感光性樹脂版の露光工程の説明用断面図（マスキング露光とレリーフ露光を終えた状態。）
【図２】バック露光を終えた状態の断面図
【符号の説明】
１．下部透明基板
２．上部透明基板
３．ネガフィルム
４．カバーフィルム
５．感光性樹脂層
６．ベースフィルム
７．マスキングフィルム
８．スペーサー
９．スペーサー
１０．スポンジテープ
１１．スポンジテープ
Ａ．大面積レリーフ部
Ｂ．小面積レリーフ部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a photosensitive resin plate for letterpress printing such as cardboard printing, film printing, preprint printing, and label printing, and more particularly to a method for improving the surface adhesiveness of the photosensitive resin plate. .
[0002]
[Prior art]
In general, the production of a printing plate using a liquid photosensitive resin is performed by the following method.
(1-a) First, as shown in FIG. 1, a negative film 3 and a cover film 4 are adhered to the lower transparent substrate 1 by means of vacuum or the like, and a photosensitive resin layer 5 is laminated thereon, The base film 6 and the masking film 7 are overlapped with each other. Thereafter, in order to determine the thickness of the photosensitive resin plate, masking exposure is performed to irradiate actinic light through the upper transparent substrate 2 placed on the set spacer 8 to form the base of the relief portion. In order to form an image of the relief portion, the exposure is performed by irradiating active light from the lower transparent substrate 1 through the negative film 3, and then the masking film 7 is removed as shown in FIG. Back exposure for stably fixing the portions A and B to the base film 6 is performed from the upper transparent substrate 2 side. Or
(1-b) Without using a masking film, the negative film 3 and the cover film 4 are placed in close contact on the lower transparent substrate 1, and the photosensitive resin layer 5 is laminated thereon, and the base film 6 is placed thereon. Overlapping. Thereafter, back exposure is performed to irradiate actinic light through the upper transparent substrate 2 placed on the spacer 8 set in order to determine the thickness of the photosensitive resin plate to form the base of the plate, and then to the lower portion. Relief exposure is performed by irradiating active light through the negative film 3 from the transparent substrate 1 side.
[0003]
(2) After washing and developing an uncured portion with a suitable detergent from the photosensitive resin plate exposed by the method (1-a) or (1-b), printing is performed by post-exposure and drying Get a version.
In general, a photosensitive resin composition that is polymerized and cured by irradiation with actinic rays remains unreacted even after being cured, and thus is more or less sticky to the surface of the obtained printing plate, that is, has adhesiveness. This is not preferable for storage, handling or use of the printing plate. In other words, when printing a plate with high adhesiveness, handling problems when loading and unloading the plate cylinder, problems of adhesion between plates and adhesion of dust at the time of placing the plate, and when the substrate to be printed is paper Includes problems such as adhesion of paper dust to the plate and paper smearing. In particular, when printing paper adhesion or paper smearing occurs due to the stickiness of the plate during printing, not only does the printing yield decrease, but it is necessary to interrupt printing and wipe the plate, resulting in reduced work.
[0004]
The post-exposure step of the plate making method is more active in order to increase the mechanical strength by curing unreacted materials inside and on the surface of the cured plate obtained after development, or to reduce the surface tackiness of the plate. Although it is a step of irradiating the printing plate with light, removal of surface tackiness is not always sufficient even with a printing plate subjected to post-exposure.
As a method for solving such a problem, at the time of post-exposure, a photosensitive resin plate is immersed in a liquid and irradiated with actinic rays (in-water post-exposure method), or after exposure in an inert gas, the photosensitive resin layer. A method for promoting surface polymerization, coating various photosensitive materials such as rubber latex and saran latex on the photosensitive resin plate to reduce the surface, or using an oxidizing agent and a reducing agent alone or in combination. A method of chemically treating these or a combination of these methods is employed. Further, as a kind of coating method, a compound having a higher alkyl group (lubricant) is contained in the photosensitive resin composition, and the surface tackiness removing method utilizing the fact that the compound crystallizes and precipitates on the printing plate surface after the plate making. Has also been proposed. However, these methods may be insufficient in the effect itself or may have a problem in handling of chemicals used even if the method is effective. Specifically, there are the following problems.
[0005]
(1) The coating method has a drawback that the coating layer is peeled off during printing, and the durability of the effect is insufficient.
(2) Depending on the type of the photosensitive resin composition, the adhesive removal itself may be insufficient even after post-exposure in an atmosphere in which oxygen is blocked, such as in a liquid or an inert gas.
[0006]
(3) In the treatment method using an oxidizing agent and a reducing agent, attention is generally required for handling of chemicals used, and rust prevention processing is required for an apparatus in contact with the treatment liquid.
In particular, the above (2) has a three-dimensional structure by efficiently carrying out radical polymerization of polymerizable double bonds in the composition by blocking oxygen, and at the same time increases mechanical strength and unreacts. In other words, the number of polymerizable double bonds in one molecule of the prepolymer is 2 or less. When it is contained, an increase in mechanical strength is observed, but the tackiness removing effect is insufficient. Even in the case where the number of polymerizable double bonds exceeds 2, a long irradiation time of active light is required to achieve a sufficient adhesive removal effect. That is, in the current plate making process, it is difficult to react all the terminal double bonds, and even if all the double bonds at the end of the prepolymer react, it is often impossible to obtain a plate having no tackiness. Therefore, in order to more fully remove the tackiness of a photosensitive resin composition containing such a prepolymer, it is effective to perform a method other than polymerization of a polymerizable double bond to crosslink the prepolymer three-dimensionally. It is.
[0007]
In Japanese Examined Patent Publication No. 56-16182, as such a three-dimensional cross-linking by a reaction other than a double bond, radicals are generated by extracting hydrogen from a prepolymer main chain in which a terminal double bond reacts with a monomer or a prepolymer. Discloses a method of crosslinking by forming bonds between prepolymer backbones. That is, after impregnating the surface layer of the radical polymerizable resin cured product with a hydrogen abstracting agent capable of extracting a hydrogen atom in the compound by irradiation with actinic rays, the impregnated portion of the cured product is 300 nm or less, Preferably, the surface tackiness of the radically polymerizable resin cured product is removed by irradiating with an actinic ray having a wavelength of 200 to 300 nm.
[0008]
In Japanese Patent Publication No. 56-16182, as a means for impregnating a hydrogen abstracting agent, a solution in which a hydrogen abstracting agent is dissolved is applied to a radically polymerizable resin cured product by brush or spray, or radical polymerization is performed on the hydrogen abstracting agent solution. The method to immerse the cured resin is cited.
[0009]
[Problems to be solved by the invention]
However, when impregnated with a hydrogen abstraction agent by the above method, the surface tack removal effect is sufficiently recognized, but compared to plate making in a normal process, it is necessary to immerse and dry in a hydrogen abstraction agent solution, and the plate making process Increase in complexity and complexity, resulting in problems such as the introduction of new equipment and an increase in plate making costs resulting from a decrease in production. That is, as a hydrogen abstracting agent solution for obtaining a sufficient surface tack removing effect, a high concentration organic solvent must be used in a large amount in order to dissolve the hydrogen abstracting agent although there is a tradeoff with the immersion time. Care must be taken in handling. If a solvent with a high flash point is used in consideration of handleability, or if a solvent with a high flash point is used by mixing with water, the solvent will not evaporate when left at room temperature. When the amount of actinic rays applied to the plate surface is reduced, the surface tackiness is not sufficiently removed and the plate surface is uneven. For this reason, forced drying is required before actinic ray irradiation, and more expensive equipment such as an explosion-proof dryer and forced exhaust device is required.
[0010]
Therefore, the present invention solves the problem of workability or productivity caused by the method of removing the surface adhesiveness of the surface layer of the cured resin using a crosslinking reaction by a conventional hydrogen abstraction agent, and letterpress printing with low surface adhesiveness. It is an object of the present invention to provide a method for making a photosensitive resin plate for use in printing.
[0011]
[Means for Solving the Problems]
1st invention of this application arrange | positions a negative film, the cover film by which the hydrogen abstraction agent solution was apply | coated to the upper part, a liquid photosensitive resin, and a base film in this order, and after removing an exposure and an unexposed part, A method for producing a photosensitive resin plate, comprising performing post-exposure by irradiating the entire plate surface with actinic rays.
[0012]
In the second invention of the present application, a negative film and a cover film are arranged in this order, and then a hydrogen abstracting agent solution is applied and arranged on the surface of the cover film, and then a liquid photosensitive resin and a base film are arranged in this order. A method for producing a photosensitive resin plate, comprising performing post-exposure by irradiating an entire surface of the plate with actinic rays after removing exposed and unexposed portions. Specific embodiments of the first invention of the present application include the following embodiments.
[0013]
(1) First, a negative film, a cover film, a liquid photosensitive resin, a base film, a masking film, and an upper transparent substrate are laminated in this order on the lower transparent substrate. First, masking exposure is performed through the upper transparent substrate, and then the lower portion. In the method of making a photosensitive resin plate by performing relief exposure through a transparent substrate, further removing the masking film, performing back exposure through the upper transparent substrate, and then removing the uncured liquid photosensitive resin. A hydrogen abstraction agent capable of extracting hydrogen atoms in the compound by irradiating is impregnated into the lower surface layer of the liquid photosensitive resin by applying and arranging it on the cover film during lamination, and then exposing, developing, and curing The subsequent surface layer is irradiated with actinic rays. Or
(2) A negative film, a cover film, a liquid photosensitive resin, a base film, and an upper transparent substrate are laminated in this order on the lower transparent substrate. First, back exposure is performed through the upper transparent substrate, and then relief exposure is performed through the lower transparent substrate. In the method of preparing a photosensitive resin plate by removing the uncured liquid photosensitive resin, a hydrogen abstraction agent capable of abstracting hydrogen atoms in the compound by irradiating with actinic rays is laminated. Occasionally, the lower surface layer of the liquid photosensitive resin is impregnated by being applied and disposed on the cover film, and then exposed and developed, and the surface layer after curing is irradiated with actinic rays.
[0014]
In the case of the second invention using the cover film on which the hydrogen abstraction agent is applied and arranged, the same aspect can be adopted except that the hydrogen abstraction agent is not applied and arranged on the cover film at the time of lamination.
In the case of the first invention of the present application, referring to the image of the negative film, it is also one of preferred embodiments that the hydrogen abstracting agent is applied only to a desired portion of the surface of the cover film.
[0015]
According to the present invention, it is possible to obtain a photosensitive resin printing plate having low printing surface adhesion without changing the conventional plate making process and plate making apparatus.
Hereinafter, the present invention will be described in more detail.
The photosensitive resin to which the method of the present invention is applied is not particularly limited. For example, JP-B-52-7761, JP-A-60-191237, JP-A-63-88555, The liquid photosensitive resin shown by Kaihei 1-245245 etc. can be used.
[0016]
Usually, when manufacturing a so-called thick plate having a plate thickness of 4 mm or more, first, a negative film 3 and a cover film 4 are overlaid on a transparent substrate 1 as shown in FIG. The negative film 3 and the cover film 4 are brought into vacuum contact with the transparent substrate 1 by the grooves and the vacuum piping. Thereafter, a hydrogen abstracting agent is applied on the cover film 4, a photosensitive resin layer 5 is further laminated, and a base film 6 and a masking film 7 are overlaid thereon. Thereafter, the transparent substrate 2 is placed on the spacer 8 set to determine the thickness of the photosensitive resin plate, and back exposure (masking) is performed for irradiating active light through the transparent substrate 2 to form the base of the relief portion. In order to form a relief portion of the image, relief exposure is performed by irradiating active light from the transparent substrate 1 side through the negative film 3. Next, the masking film 7 is removed, and back exposure for fixing the formed relief portions A and B and the base film 6 is performed from the transparent substrate 2 side.
[0017]
Next, the uncured photosensitive resin is washed and removed with a suitable detergent, and post-exposure and drying are performed to obtain a printing plate.
The hydrogen abstraction agent used in the present invention is preferably an organic carbonyl compound that can be excited by irradiation with actinic rays to extract a hydrogen atom in another compound. However, the hydrogen abstraction reaction is another reaction of an excited carbonyl group. For example, a Norrish type 1 reaction, that is, a reaction in which a carbonyl compound undergoes α-position cleavage under light irradiation, or a type 2 reaction, that is, a ketone having hydrogen that is extracted to the γ position of a carbonyl group is irradiated with light. An organic carbonyl compound that exhibits a reaction comparable to or higher than the reaction under which an olefin and a low-molecular-weight ketone compound are cleaved is suitable.
[0018]
Representative organic carbonyl compounds that can be used in the present invention include, for example, benzophenone, 4-bromobenzophenone, 4 · 4′-dichlorobenzophenone, 4-methylbenzophenone, 4-hydroxybenzophenone, 3 · 5-hydroxybenzophenone, 4 -Substituted or unsubstituted benzophenones such as phenylbenzophenone; acetophenone, 4-methylacetophenone, 3,5-dimethylacetophenone, 4-methoxyacetophenone, 2- or 4-chloroacetophenone, 2-chloro-3- (or 5-) nitro Substituted or unsubstituted acetophenones such as acetophenone, α-chloro-α-phenylacetophenone, α, α-dichloroacetophenone, 2,6-dimethoxyacetophenone, 4-hydroxyacetophenone; Zoin, phenyl naphthyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin-i-propyl ether, benzoin-n-butyl ether, benzoin-i-butyl ether Substituted or unsubstituted aromatic ketones such as benzoin alkyl ether compounds such as tereline and benzoin-t-butyl ether; p-benzoquinone, 2,5-dimethyl-p-benzoquinone, 2,6-dichloro-p-benzoquinone 9,10-anthraquinone, 2-bromoanthraquinone, 1-nitro-2-carboxy-9.10-anthraquinone, 2-ethylquinone, 2-ethyl-5,6,7,8-tetrahydroanthraquinone, 1 4-naphthoquinone, 2,3-dichloronaphthoquinone, 2,3- Various o-p-quinone compounds such as methyl-1,4-naphthoquinone, 2-ethyl-1,4-naphthoquinone, phenanthraquinone, 1,2-naphthoquinone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, Various organic carbonyl compounds such as substituted or unsubstituted thioxanthones such as 2-isopropylthioxanthone can be used as the hydrogen abstraction agent of the present invention.
[0019]
As a preferable example of such a hydrogen abstracting agent, the organic carbonyl compound is a compound in which at least one substituted or unsubstituted aromatic is bonded to the carbonyl carbon, and in the following formula 1, formula 2 or formula 3, The organic carbonyl compound having the structure represented is effective as the hydrogen abstracting agent of the present invention. At least one compound represented by Formula 1, Formula 2 or Formula 3 may be used. Of course, two or more hydrogen abstracting agents may be used in combination.
[0020]
[Chemical 1]

[0021]
(In formula 1, R1 and R2 are hydrogen atoms, alkyl groups having 1 to 5 carbon atoms, alkoxyl groups having 1 to 5 carbon atoms, halogen atoms of F, Cl, Br and I, and hydroxy groups having 1 to 5 carbon atoms. It is a group selected from an alkyl group, a hydroxyalkoxyl group having 1 to 5 carbon atoms, and a quaternary ammonium salt derivative.)
[0022]
[Chemical 2]

[0023]
(In Formula 2, X1 is a hydrogen atom, a halogen atom of F, Cl, Br, or I, an alkoxyl group having 1 to 5 carbon atoms, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, or a hydroxy group having 1 to 5 carbon atoms. R3 is an alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, 1 to 5 carbon atoms, and a group selected from an alkyl group and a hydroxyalkoxyl group having 1 to 5 carbon atoms. 5 alkoxyl groups, hydroxyalkoxyl groups having 1 to 5 carbon atoms, quaternary ammonium salt derivatives,
[0024]
[Chemical 3]

[0025]
(However, X2 is a halogen atom of F, Cl, Br, or I, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, or a carbon number. 1-5 hydroxyalkoxyl groups and quaternary ammonium salt derivatives). )
[0026]
[Formula 4]

[0027]
(In Formula 3, R4, R5, and R6 are each a hydrogen atom, a halogen atom of F, Cl, Br, or I, an alkoxyl group having 1 to 5 carbon atoms, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, or 1 carbon atom. A group selected from a hydroxyalkyl group of -5, a hydroxyalkoxyl group having 1 to 5 carbon atoms, and a quaternary ammonium salt derivative.)
Moreover, the derivative | guide_body of Formula 1, Formula 2 or Formula 3 which has a polymerizable double bond can also be used as a hydrogen abstraction agent of this invention.
[0028]
Specific examples of such compounds include benzophenone, 4 · 4′-dimethoxybenzophenone, 4-hydroxybenzophenone, deoxybenzoin, acetophenone, 4-methylacetophenone, 2-chloroacetophenone, anthraquinone, 2-methylanthraquinone, 2-ethyl. Anthraquinone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and the like can be exemplified.
The quaternary ammonium salt derivatives of Formula 1, Formula 2 or Formula 3 include (2-acryloyloxy) (4-benzoylbenzyl) dimethylammonium bromide salt, (4-benzoylbenzyl) trimethylammonium chloride, 2- (3 -Dimethylamino-2-hydroxypropoxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride and the like.
[0029]
Any method may be used for impregnating the surface layer of the uncured resin with the hydrogen abstraction agent. For example, a treatment liquid obtained by dissolving the hydrogen abstraction agent in an appropriate solvent is applied onto the cover film by brushing or spraying. A method of applying and then laminating a liquid photosensitive resin is practical. Moreover, you may plate-making using the cover film previously apply | coated with the hydrogen abstraction agent.
[0030]
Any solvent can be used as long as it can dissolve the hydrogen abstracting agent. However, if the solvent is not sufficiently evaporated, unevenness in relief formation occurs, and a solvent having a high evaporation rate at room temperature is more preferable. When the hydrogen abstracting agent is used as a solution, if the concentration is at most 2 parts by weight with respect to 100 parts by weight of the solvent, the effect of removing surface tackiness is sufficiently exhibited. It is meaningless to increase the concentration too much. Rather, when the uncured resin after exposure is recovered and reused, the sensitivity characteristics of the resin are impaired, which is not preferable.
[0031]
At the time of post-exposure, the actinic ray irradiated to the resin plate impregnated with the hydrogen abstraction agent after curing needs to have a wavelength in a wavelength region that excites the hydrogen abstraction agent efficiently. When the above-described organic carbonyl compound is used as a hydrogen abstracting agent, it is preferable to use ultraviolet rays, particularly ultraviolet rays having a wavelength distribution in a short wavelength region of 300 nm or less. However, when irradiating an actinic ray having a wavelength of 200 nm or less in the air, generation of ozone and oxidation reaction to the cured product cannot be ignored. Therefore, an actinic light source having a distribution in the wavelength region of 200 to 300 nm is preferable. Examples of such an active light source include a low-pressure mercury lamp, a germicidal lamp, and a deuterium lamp.
[0032]
The appropriate exposure amount for obtaining a sufficient surface adhesive removal effect varies depending on the resin composition of the cured resin plate and the impregnation amount of the hydrogen abstracting agent with respect to the resin composition, but is at least 500 mJ / cm ² (Oak Seisakusho UV-M02 The amount of irradiation at a wavelength of 250 nm is measured by the above and a value calculated from the irradiation time) is required, and it is usually preferable to expose in the range of 1000 to 3000 mJ / cm 2. An exposure amount of 5000 mJ / cm ² or more is not preferable because minute cracks are generated on the plate surface.
[0033]
In the present invention, after the impregnation with a hydrogen abstracting agent, the exposed and developed cured resin plate may be irradiated with actinic rays at the same time as the post-exposure step that is usually performed in plate making, or a separate exposure step may be performed. It may be provided. In other words, the post-exposure step for normal plate making is irradiation of actinic light to a post-development cured product whose main purpose is to promote mechanical strength, and an active light source having a distribution in a wavelength region of 300 nm or more used for relief exposure (for example, high pressure) Mercury lamps, ultra-high pressure mercury lamps, ultraviolet fluorescent lamps, carbon arc lamps, xenon lamps, etc.) and active light sources having a distribution in the wavelength region of 200 to 300 nm are used in combination. It can be used in the post-exposure process, which is preferable in terms of productivity.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to examples.
(Evaluation of tackiness of printing plate surface)
Diameter 50 mm, the circumference surface of the aluminum wheel width 13mm those stuck poly ethylene film is brought into contact with the relief surface layer wiping advance deposit and left aluminum wheels under a load of 500 g 4 seconds Thereafter, the aluminum ring is pulled up at a speed of 30 mm per minute, and a tack tester (manufactured by Toyobo Co., Ltd.) that reads the adhesive force when the aluminum ring is separated from the relief surface with a pushbull gauge is used. A smaller value measured by a tack tester can be said to be a printing plate having no surface tackiness. However, in this adhesive evaluation, in the state where there is no coating layer that peels off at the time of printing, that is, when the photosensitive resin composition contains a lubricant for the purpose of removing surface adhesiveness, the lubricant is removed and the photosensitive layer is removed. The stickiness of the conductive resin substrate must be measured.
[0035]
When the value indicated by the tack tester exceeds about 50 g, foreign matter adheres to the surface of the printing plate and the printed matter is defective. When the value exceeds 100 g, the plates are in close contact with each other when the printing plates are placed on top of each other. When the printed material is paper, a paper blur phenomenon occurs due to adhesion between the printing surface and the paper. As a good non-tacky printing plate, 0 g is desirable, but if it is 50 g or less, it is considered that problems due to tackiness cannot occur practically. In liquid photosensitive resin printing plates that are considered to have particularly poor adhesiveness among printing plates, when the tackiness tester does not take any measures for removing surface adhesiveness, it is common that the indicated value by the tack tester exceeds 100 g. is there.
[0036]
【Example】
A liquid photosensitive resin APR: F-47 (Asahi Kasei Kogyo Co., Ltd.) was used to make a 7 mm thick resin plate using an AWF type plate making machine (Asahi Kasei Kogyo Co., Ltd.). In the molding process, a negative film and a cover film are laminated on the lower transparent substrate, and an ethyl alcohol solution containing 20 g / liter of benzophenone is applied onto the cover film using a brush. Resin APR: F-47 was laminated, a polyester base film and a masking film were laminated thereon, and an upper transparent substrate was placed thereon. A space between the two substrates was held by a spacer. Next, vacuum suction is performed from the upper and lower transparent substrates and held for 3 minutes while maintaining the adhesion between the negative film and the masking film, and then the masking exposure is performed for 125 seconds by irradiating active light through the upper transparent substrate and the masking film. Relief exposure of irradiating active light through the substrate and negative film was performed for 130 seconds, and the masking film was removed. Next, back exposure by irradiating active light through the upper transparent substrate was performed for 20 seconds to complete image formation exposure.
[0037]
The photosensitive layer thus exposed is washed with a washing solution according to a conventional method and developed, and then the developed plate is immersed in tap water, and an ultraviolet fluorescent lamp (exposure amount 2000 mJ / cm ² ), germicidal lamp (exposure amount 1000 mJ). / Cm ² ) post-exposure was performed.
The tackiness of the plate surface obtained in this way was measured with a tack tester to find 15 g. After the measurement, the plate surface was vigorously wiped with a cloth soaked with ethyl alcohol, and after the ethyl alcohol had volatilized, the plate It was 20g when the adhesiveness of the surface was measured with the tack tester.
[0038]
[Comparative example]
Except for applying an ethyl alcohol solution of benzophenone, the tackiness of the plate surface produced in the same manner as in the examples was measured with a tack tester, which was 200 g. After the measurement, the plate surface was soaked with ethyl alcohol. After violently wiping with a cloth and ethyl alcohol volatilized, the tackiness of the plate surface was measured with a tack tester to be 400 g.
[0039]
【The invention's effect】
In the method for producing a photosensitive resin printing plate according to the present invention, there is no need to increase a series of work steps such as an exposure step, a development step, a post-exposure step, and a drying step, which are cited as printing plate making steps using a liquid photosensitive resin. There is no impact on the plate making cost. In addition, the photosensitive resin plate obtained by the present invention does not show the adhesiveness of the plate surface before and after printing and during printing, and foreign matter adheres to the plate surface during printing and placing after printing. Therefore, there is no need to perform operations such as wiping the plate surface, and the workability can be handled almost the same as when a rubber plate is used.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining an exposure process of a photosensitive resin plate (a state where masking exposure and relief exposure are completed).
FIG. 2 is a cross-sectional view after back exposure is completed.
1. 1. Lower transparent substrate 2. Upper transparent substrate Negative film4. 4. Cover film 5. Photosensitive resin layer Base film7. Masking film8. Spacer 9. Spacer 10. Sponge tape11. Sponge tape Large area relief B. Small area relief

Claims (5)

A negative film, a cover film coated with a hydrogen abstraction agent solution (excluding those containing polyvinyl alcohol) , liquid photosensitive resin and base film are placed in this order to remove exposed and unexposed parts. And then performing post-exposure by irradiating the entire surface of the plate with actinic rays. After placing the negative film and cover film in this order, apply the hydrogen abstracting agent solution on the cover film surface, then place the liquid photosensitive resin and base film in this order, and remove the exposed and unexposed parts. And then performing post-exposure by irradiating the entire surface of the plate with actinic rays. The method for producing a photosensitive resin plate according to claim 1, wherein the hydrogen abstraction solution is applied and then dried at room temperature. The method for producing a photosensitive resin plate according to claim 1 or 2, wherein the application and arrangement of the hydrogen abstracting agent solution on the surface of the cover film is performed only on a desired portion with reference to an image of the negative film. . The method for producing a photosensitive resin plate according to claim 1 or 2, wherein the hydrogen abstraction solution applied to the cover film surface comprises a hydrogen abstraction agent and a solvent.

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