JP2009186859A - Waterless lithographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waterless lithographic printing plate precursor having excellent image reproducibility not only immediately after production but also after long-term storage of the plate material. <P>SOLUTION: The waterless lithographic printing plate precursor has at least a radical polymerizable photosensitive layer and an ink-repellent layer on a support in this order, wherein the waterless lithographic printing plate precursor contains an acetophenone-based polymerization initiator and a triphenylmethane-based dye in the photosensitive layer. A more excellent waterless lithographic printing plate precursor can be obtained by adding an additive polymerization inhibitor to the radical polymerizable photosensitive layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a waterless lithographic printing plate precursor, and more particularly to a positive waterless lithographic printing plate precursor using a radical polymerizable photosensitive layer that polymerizes using radicals generated by irradiation with actinic rays.

  Conventionally, various printing plates have been proposed for performing lithographic printing (hereinafter referred to as waterless printing) using silicone rubber or fluorine resin as an ink repellent layer without using dampening water. In such waterless printing, the image area and the non-image area are on the same plane, and the difference in ink adhesion is utilized with the image area as the ink receiving layer and the non-image area as the ink repellent layer. This means a lithographic printing method in which ink is applied only to the image area and then transferred to a printing medium such as paper, and printing can be performed without using dampening water. is there.

  As a positive type waterless lithographic printing plate precursor using a silicone rubber as an ink repellent layer and having an actinic ray irradiation part as a non-imaged part, water having a radical polymerizable photosensitive layer and a silicone rubber layer laminated on a support is used. None Planographic printing plate precursors are known. Such a positive waterless planographic printing plate precursor is exposed through a transparent original (hereinafter referred to as a positive film) having a line image, a halftone dot image, and the like. By developing after exposure, only the ink repellent layer in the unexposed area or only the ink repellent layer and the photosensitive layer are peeled off to form an ink-thinned image area.

  The radical polymerizable photosensitive layer generally employs a mechanism in which a photosensitive layer is polymerized using radicals generated by irradiation with actinic rays and the upper silicone rubber layer adheres. However, there is a problem that most of the generated radicals disappear due to oxygen present in the plate material, particularly at the photosensitive layer or the photosensitive layer-silicone rubber layer interface, and the polymerization reaction does not proceed well. As one method for solving this problem, a method of providing an oxygen permeation preventive coating layer on a silicone rubber layer has been proposed (see, for example, Patent Document 1). Although this method can suppress the absorption of oxygen into the plate during exposure, the effect of oxygen originally contained in the plate cannot be suppressed, and the effect is not sufficient.

  As another method, a method of adding a polymerization inhibitor of a phenol, amine, sulfur, phosphorus, or anthraquinone derivative to the photosensitive layer has been proposed (for example, see Patent Document 2). However, in order to capture oxygen during exposure using this method, it is necessary to add a large amount of a polymerization inhibitor, but on the other hand, a large amount of polymerization inhibitor delays radical polymerization itself, and the polymerization reaction proceeds well. There was a problem that there was no.

As yet another method, a method of using an acetophenone polymerization initiator in the photosensitive layer and adding a thiophosphite compound has been proposed (see, for example, Patent Document 3). Since the thiophosphite compound preferentially captures oxygen contained in the plate during exposure, oxygen deactivation of the generated radicals is suppressed, the polymerization reaction of the photosensitive layer is promoted, and good image reproducibility is achieved. Be able to get. However, such a thiophosphite compound is prone to spontaneous oxidative degradation due to oxygen even at room temperature, and has a problem that its effect is greatly reduced by long-term storage of the plate material. The development of materials was desired.
JP-A-50-59101 (Claims) JP-A-9-244243 (Claims) JP 2007-233346 A (Claims)

  An object of the present invention is to solve such problems of the prior art, and provide a waterless lithographic printing plate precursor having excellent image reproducibility even when the plate material is stored for a long period of time as well as immediately after production. There is.

  The present invention relates to a waterless lithographic printing plate precursor having at least a radical polymerizable photosensitive layer and an ink repellent layer in this order on a support, the acetophenone polymerization initiator and the triphenylmethane dye in the radical polymerizable photosensitive layer. Is a waterless lithographic printing plate precursor characterized by comprising

  According to the present invention, it is possible to provide a waterless lithographic printing plate precursor having excellent image reproducibility even when the plate material is stored for a long period of time.

  Hereinafter, the configuration of the present invention will be described more specifically.

  As a result of diligent investigation to solve the problem of storage stability, the present inventors have excellent image reproducibility even when stored for a long time with two combinations of an acetophenone polymerization initiator and a triphenylmethane dye. I found out.

  The radical polymerizable photosensitive layer used in the present invention is a layer that is polymerized utilizing radicals generated by irradiation with actinic rays. The greatest feature of the present invention is that the photosensitive layer contains an acetophenone polymerization initiator and a triphenylmethane dye.

  An acetophenone-based polymerization initiator is a good polymerization initiator, but is a self-cleavage type polymerization initiator and generates two radicals per molecule, and is therefore an extremely sensitive initiator for ultraviolet rays. Therefore, radicals are generated by receiving ultraviolet rays during long-term storage, which is not preferable from the viewpoint of long-term storage. On the other hand, since the triphenylmethane dye has a resonance stable structure, even if a radical is generated, it can be taken into the molecule. Therefore, by combining these two, even if radicals are generated from the acetophenone polymerization initiator during long-term storage, the triphenylmethane dye prevents the reaction from running out of control by taking in the radicals. It will have sex. On the other hand, when irradiated with actinic rays after long-term storage, the acetophenone polymerization initiator generates radicals all at once, so that the reaction between the image area and the non-image area can be clarified. Therefore, it is possible to achieve both excellent image reproducibility and storage stability.

  Specific examples of the acetophenone-based polymerization initiator used in the present invention are described below, but are not limited thereto.

  Benzyldimethyl ketal, methoxyacetophenone, 4-phenoxydichloroacetophenone, 4-t-butyltrichloroacetophenone, diethoxyacetophenone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl- 1- (4-dodecylphenyl) propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (2-hydroxyethoxyphenyl) -2-hydroxy-2-methylpropane- 1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxy Cyclohexyl-phenyl ketone, 2-methyl-2-morpholine -1-thiomethylphenylpropan-1-one, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, α-acyloxime ester, 2-benzyl-2-dimethylamino-1- ( Examples include acetophenone series such as 4-morpholinophenyl) -butanone and α-hydroxy-α, α′-dimethylacetophenone.

  The content of the acetophenone polymerization initiator is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more as the lower limit in the total solid content of the photosensitive layer. Moreover, as an upper limit, 20 weight% or less is preferable and it is more preferable that it is 15 weight% or less. If it is 0.01% by weight or more, oxygen trapping in the system at the time of exposure will occur sufficiently, and if it is 20% by weight or less, the occurrence of bleed-out and adverse effects on the photosensitive properties can be prevented.

  Specific examples of the triphenylmethane dye used in the present invention are described below, but are not limited thereto.

  3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide 3,3-bis (p-dimethylaminophenyl) -6-diethylamino Phthalide, 3,3-bis (n-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-diatylaminophenylphthalide) brilliant green, ethyl violet, methyl violet, methyl green, erythrosine B, Basic fuchsin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, cyano-p-diethylaminophenylacetanilide and the like can be mentioned.

  The content of the triphenylmethane dye is preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total solid content of the photosensitive layer. When the amount used is less than 0.05% by weight, the plate material is not sufficiently dyed, and when it is more than 10% by weight, the printing durability of the printing plate tends to be lowered.

  As the photosensitive layer used in the present invention, the radical polymerizable photosensitive layer proposed so far can be used except that it contains an acetophenone polymerization initiator and a triphenylmethane dye. That is, it is a layer containing a monomer capable of radical polymerization, and may contain various additives such as a binder polymer, a polymerization inhibitor, a dye, and a sensitizer as necessary.

  As monomers capable of radical polymerization, monomers containing amino groups such as those described in JP-A-6-118629 and JP-A-7-110573, JP-A-8-184960 and JP-A-10- Monomers that do not contain an amino group as described in Japanese Patent No. 339946 can be used alone or in combination. Further, an oleophilic monomer as described in JP-A-6-21091 may be included for the purpose of promoting a polymerization reaction at a low temperature, and JP-A-5-2005-5 can be used to improve the adhesive force with the upper ink repellent layer. You may include the silylated monomer described in 333535 gazette.

  Examples of the binder polymer include polyvinyls, polyacryls, polyoxides, polyesters, polyurethanes, polyamides, and unvulcanized rubbers having a glass transition temperature of 20 ° C. or less described in JP-A-10-123699. Polymers can be used alone or in combination.

  As the polymerization inhibitor, a chain transfer type, addition type or stable radical type polymerization inhibitor can be used.

  As a result of diligent studies to solve the storage stability problem, the present inventors have also found that the storage stability is further improved by using an addition-type polymerization inhibitor.

  Since the addition type polymerization inhibitor contains a polar group in the molecule, the affinity with other components constituting the photosensitive layer is increased, and carbonization commonly used as a solvent for the ink repellent layer composition liquid. Compatibility with a hydrogen-based solvent decreases. Therefore, more excellent storage stability can be obtained.

  Examples of the addition type polymerization inhibitor include anthraquinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, nitro compounds and the like.

Specifically, 2,5-diphenyl-1,4-benzoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 1 -(Methylamino) anthraquinone, 1-bromoanthraquinone, 2-bromoanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2,3-dimethylanthraquinone, 1,5-dibromoanthraquinone, 2,6-dibromoanthraquinone, 1, 4-dichloroanthraquinone, 1,5-dichloroanthraquinone, 1,8-dichloroanthraquinone, 1,2-benzanthraquinone, bianthrone, N, N'-dimethylquinacridone, flavantron, 1,1'-iminodianthraquinone, in Nthrone, isoviolanthrone, 5,7,12,14-pentacentetron, 8,16-pyrantorangeone, 3,3 ′, 5,5′-tetra-tert-butyl-4,4′-stilbenequinone, vitamin K ₁ , coenzyme Q _{10 and the} like can be mentioned.

  Among them, from the viewpoints of solubility in the photosensitive layer composition liquid for forming the photosensitive layer, production line contamination due to sublimation during heating, and safety, a halogen atom or a hydrocarbon group having 1 or more carbon atoms is directly present. Or 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 1- (methylamino) anthraquinone, which are anthraquinone derivatives introduced through oxygen, nitrogen, sulfur, or phosphorus, -Bromoanthraquinone, 2-bromoanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2,3-dimethylanthraquinone, 1,5-dibromoanthraquinone, 2,6-dibromoanthraquinone, 1,4-dichloroanthraquinone, 1,5 -Dichloroanthraquinone, 1, - dichloro anthraquinone, be used 1,2-anthraquinone preferred.

  The content of the addition-type polymerization inhibitor is preferably 0.005% by weight or more, more preferably 0.01% by weight or more in the total solid content of the photosensitive layer. Moreover, 1 weight% or less is preferable and 0.5 weight% or less is more preferable. If it is 0.005% by weight or more, the radical polymerization reaction of the monomers due to long-term storage of the original plate can be effectively suppressed, and if it is 1% by weight or less, the photoradical polymerization reactivity of the photosensitive layer is hardly adversely affected.

  Furthermore, the photosensitive layer may contain appropriate amounts of various additives such as pigments, pH indicators, print-out agents, surfactants, acids and bases as required.

  Examples of the ink repellent layer used in the present invention include a condensation reaction type silicone rubber layer or an addition reaction type silicone rubber layer as described in JP-A-2005-331924.

  In the present invention, a primer layer can be provided on the support described later for the purpose of improving adhesion between the support and the photosensitive layer, preventing light halation, improving plate inspection, and improving printing durability. Examples of the primer layer that can be suitably used in the present invention include a primer layer described in JP-A-10-123699.

  As the support used in the present invention, known dimensionally stable paper, metal, film and the like conventionally used as a support for printing plates can be used. Specifically, paper, paper laminated with plastic (polyethylene, polypropylene, polystyrene, etc.), aluminum (including aluminum alloy), zinc, copper and other metal plates, cellulose acetate, polyethylene terephthalate, polyethylene, polyester, polyamide, Examples thereof include a plastic film such as polyimide, polystyrene, polypropylene, polycarbonate, and polyvinyl acetal, and a paper or plastic film on which the above metal is laminated or vapor-deposited. The plastic film can be either transparent or opaque. Among these, the use of an opaque film is preferable from the viewpoint of plate inspection.

  Of these supports, an aluminum plate is particularly preferred because it is extremely dimensionally stable and inexpensive. A polyethylene terephthalate film is particularly preferable as a flexible substrate for light printing.

  The positive-type waterless lithographic printing plate precursor constituted as described above preferably has a protective film for the purpose of protecting the ink repellent layer. As the protective film, a film of 100 μm or less that transmits light of the exposure light source wavelength satisfactorily is preferable. Representative examples include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, cellophane, and the like. Among these, a polyethylene terephthalate film having low oxygen permeability is particularly preferable from the viewpoint of storage stability of the plate material.

  For the purpose of preventing exposure of the original plate due to exposure, various light absorbers, photobleachable substances, and photochromic substances as described in JP-A-2-063050 may be provided on the protective film. . For the purpose of such protection from exposure, it is important not to suppress the radical polymerization reaction of the photosensitive layer during the main exposure.

  In the case of exposure using a positive film, from the viewpoint of improving the adhesion to the positive film, a protective film processed to have an unevenness as described in JP-A-55-55343 and JP-A-2-063051 is used. It is preferable to use it.

  Examples of the method for producing the positive waterless planographic printing plate precursor of the present invention include the following methods.

  A primer layer, a photosensitive layer, and an ink repellent layer are laminated on the support as necessary. Each of these layers is generally formed by applying and drying the composition liquid of each layer. For application of each composition liquid, slit die coater, direct gravure coater, offset gravure coater, reverse roll coater, natural roll coater, air knife coater, roll blade coater, varibar roll blade coater, two stream coater, rod coater, Wire bar coaters, dip coaters, curtain coaters, spin coaters and the like can be used. A known hot air oven or infrared oven can be used for drying.

  Thereafter, if necessary, a protective film may be laminated, or a slip sheet may be provided on the protective film.

  The lithographic printing plate precursor thus obtained is exposed imagewise by exposure through a positive film or laser scanning exposure with digital data. Examples of exposure light sources include carbon arc lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, fluorescent lamps, tungsten lamps, halogen lamps, ultraviolet lasers, visible light lasers, and (near) infrared light. A laser etc. are mentioned.

  After the exposure, if there is a protective film, it is peeled off and then developed. The development process may be a manual process or an automatic developing machine. By development processing, only the ink repellent layer in the unexposed area, or only the ink repellent layer and the photosensitive layer in the unexposed area are selectively removed to form an image area.

  As the automatic developing machine, a pre-processing unit, a developing unit, and a post-processing unit are preferably provided in this order, and more preferably a water-washing unit is provided after the post-processing unit. Specific examples of such an automatic developing machine include TWL-650 and TWL-1160 (both manufactured by Toray Industries, Inc.), JP-A-4-2265, JP-A-5-2272, and JP-A-5-205. Examples thereof include an automatic processor disclosed in Japanese Patent No. 6000 and the like, and these can be used alone or in combination.

  As the pretreatment liquid, the developer, and the posttreatment liquid, development of a waterless lithographic printing plate precursor as described in JP-A-4-163557, JP-A-4-343360, and JP-A-9-34132 is described. What was disclosed with respect to can be used. Specific examples of the pretreatment liquid include PP-1, PP-3, PP-F, PP-FII, PTS-1, and CP-1 (all manufactured by Toray Industries, Inc.). Specific examples of the post-treatment liquid include PA-1, PA-2, and PA-F (all manufactured by Toray Industries, Inc.).

  In the case where the developed printing plates are stacked and stored, it is preferable to sandwich a slip sheet between the plates for the purpose of protecting the printing plate.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(Image reproducibility evaluation)
A Gretag Macbeth spectrophotometer (manufactured by Gretag Macbeth Co., Ltd.) was used for evaluation of a 1 to 10% halftone dot (175 dpi) of a waterless planographic printing plate precursor obtained by exposure and development. Paper white measured the non-image area (exposed area), solid measured the image area (unexposed area), and after setting the reference, 1 to 10% halftone dots were measured. If 5% or less is reproduced, it can be said that the storage stability is good.

Example 1
The following primer layer composition liquid is applied onto a 0.24 mm thick degreased aluminum support (manufactured by Mitsubishi Aluminum Co., Ltd.) and dried at 200 ° C. for 1 minute to form a primer layer having a thickness of 3 g / m ^2. Provided.

<Titanium oxide dispersion>
N, N-dimethylformamide: in 10 parts by weight, titanium oxide “Taipeku” CR-50 (manufactured by Ishihara Sangyo Co., Ltd.): 10 parts by weight, glass beads: (φ = 1.5 to 2.5 mm): 15 Part by weight was added and stirred vigorously for 20 minutes. Thereafter, the glass beads were removed to obtain a titanium oxide dispersion.

<Primer layer composition liquid>
(A) Epoxy resin “Epicoat” 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 78.5 parts by weight (b) Titanium oxide dispersion: 20 parts by weight (c) 1 mol of diphenylmethane-4,4′-diisocyanate and methyl ethyl keto Reactive substance of 2 moles of oxime: 4.5 parts by weight (d) Surfactant “Florard” FC470 (manufactured by Sumitomo 3M): 0.01 parts by weight (e) Leveling agent “Disparon” LC951 (Takamoto Kasei Co., Ltd.) )): 0.05 parts by weight (f) Dibutyltin diacetate: 0.1 parts by weight (g) Resole resin “Sumilite Resin” PR-54573 (manufactured by Sumitomo Durres Co., Ltd.): 3 parts by weight (h) Tetrahydrofuran: 400 parts by weight (i) N, N-dimethylformamide: 165 parts by weight.

Subsequently, the following photosensitive layer composition liquid was apply | coated on the said primer layer, and it heated at 120 degreeC for 1 minute, and provided the photosensitive layer with a film thickness of 4 g / m < ² >.

<Photosensitive layer composition solution>
(A) Polyurethane “Samprene” LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd.): 335 parts by weight (b) Reaction product of 1 mol of m-xylylenediamine and 4 mol of glycidyl methacrylate: 10 parts by weight (c) Polyoxy Reaction product of 1 mol of propylenediamine and 4 mol of glycidyl methacrylate: 10 parts by weight (d) “Light Ester” 1 · 10DC (manufactured by Kyoeisha Chemical Co., Ltd.): 8 parts by weight (e) Polyoxypropylenediamine / glycidyl methacrylate / 3 -Glycidoxypropyltrimethoxysilane = 1/3/1 mole of reactant: 2 parts by weight (f) Hindered phenolic antioxidant: "Plastanox" 1729 (American Cyanamid Co.): 1 part by weight (g) Acetophenone photopolymerization initiator “Irgacure” 651 (Ciba Geigy) Manufactured by :) 10 parts by weight (h) Triphenylmethane dye “Oil Blue” 613 (manufactured by Orient Chemical Co., Ltd.): 0.3 parts by weight (i) Surfactant “Florard” FC470 (Sumitomo 3M) Manufactured): 0.03 parts by weight (j) chain transfer polymerization inhibitor: hydroquinone mono-ethyl ether: 0.02 parts by weight (k) ethyl cellosolve: 150 parts by weight (l) methyl ethyl ketone: 400 parts by weight (m) Tetrahydrofuran: 200 parts by weight.

Next, the following silicone rubber layer composition solution prepared immediately before coating was coated on the photosensitive layer and heated at 120 ° C. for 1 minute to provide a silicone rubber layer having a thickness of 2.0 g / m ² .

<Silicone rubber layer composition liquid>
(A) α, ω-dihydroxypolydimethylsiloxane: DMS-S42 (weight average molecular weight 77,000, manufactured by GELEST Inc.): 100 parts by weight (b) ethyltriacetoxysilane: 10 parts by weight (c) dibutyltin diacetate : 0.1 part by weight (d) “Isopar” E (Esso Chemical Co., Ltd.): 990.9 parts by weight.

  A polyethylene terephthalate film having a film thickness of 6 μm was laminated as a protective film on the silicone rubber layer to obtain a positive waterless lithographic printing plate precursor.

  Prepare the positive-type waterless lithographic printing plate precursor obtained at 50 ° C. for 1 month, 50 ° C. × 2 months, and 50 ° C. × 3 months, and expose each under the following exposure conditions. Further, a waterless lithographic printing plate was obtained by performing development under the following development conditions. Table 1 shows the image reproducibility evaluation results of the obtained waterless lithographic printing plate.

(Exposure conditions)
Exposure exposure system using positive film: "Idle Fin" ID-2000 (Oak Manufacturing)
Light meter: “Light measure” UV365 (Oak Manufacturing)
Exposure conditions: After positive film vacuum contact (30 seconds), 11 mW / cm ² (365 nm light) × 60 seconds exposure exposure plate temperature: 25 ° C. (room temperature exposure)
Film: Positive film-halftone dot 1% to 10% (175 lpi)

(Development conditions)
Developer: “TWL-650” (manufactured by Toray Industries, Inc.)
Developer (pretreatment solution): 35 ° C. “PP-F” (manufactured by Toray Industries, Inc.)
Developer (developer): Tap water developer (post-treatment solution): “PA-F” (manufactured by Toray Industries, Inc.)
Development speed: 100 cm / min

(Example 2)
Positive waterless lithographic printing in the same manner as in Example 1 except that the chain transfer polymerization inhibitor hydroquinone mono-ethyl ether of the photosensitive layer composition liquid was changed to the addition polymerization inhibitor anthraquinone derivative 2-ethylanthraquinone. The plate original plate was prepared and evaluated. The evaluation results are shown in Table 1.

(Example 3)
The same method as in Example 1 except that the chain transfer polymerization inhibitor hydroquinone mono-ethyl ether in the photosensitive layer composition solution was changed to the addition polymerization inhibitor benzoquinone derivative 2,5-diphenyl-1,4-benzoquinone. The positive type waterless lithographic printing plate precursor was prepared and evaluated. The evaluation results are shown in Table 1.

Example 4
In the same manner as in Example 1, except that the chain transfer polymerization inhibitor hydroquinone mono-ethyl ether in the photosensitive layer composition solution was changed to the addition type polymerization inhibitor naphthoquinone derivative 2-hydroxy-1,4-naphthoquinone. The production and evaluation of a waterless planographic printing plate precursor were carried out. The evaluation results are shown in Table 1.

(Comparative Example 1)
The same as in Example 1 except that the triphenylmethane dye “oil blue” 613 of the photosensitive layer composition solution was changed to triallylmethane “Eisen Victoria Pure Blue” -BOH Conch (manufactured by Hodogaya Chemical Co., Ltd.). The positive waterless lithographic printing plate precursor was prepared and evaluated by the above method. The evaluation results are shown in Table 1.

(Comparative Example 2)
A positive waterless lithographic printing plate precursor in the same manner as in Example 1 except that the acetophenone photopolymerization initiator “Irgacure” 651 in the photosensitive layer composition solution was changed to thioxanthone photopolymerization initiator 2,4-diethylthioxanthone. Were prepared and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 3)
Positive waterless lithographic printing plate in the same manner as in Example 2 except that the triphenylmethane dye “oil blue” 613 of the photosensitive layer composition liquid was changed to triallylmethane “Eisen Victoria Pure Blue” -BOH Conch The original plate was prepared and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 4)
A positive waterless planographic printing plate precursor in the same manner as in Example 2 except that the acetophenone photopolymerization initiator “Irgacure” 651 in the photosensitive layer composition solution was changed to thioxanthone photopolymerization initiator 2,4-diethylthioxanthone. Were prepared and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 5)
A positive waterless lithographic printing plate precursor was prepared and evaluated in the same manner as in Example 1 except that the photosensitive layer composition liquid was changed to the following <Photosensitive layer composition liquid-2>. The evaluation results are shown in Table 1.

<Photosensitive layer composition liquid-2>
(A) Polyurethane “Samprene” LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd.): 335 parts by weight (b) Reaction product of 1 mol of m-xylylenediamine and 4 mol of glycidyl methacrylate: 10 parts by weight (c) Polyoxy Reaction product of 1 mol of propylenediamine and 4 mol of glycidyl methacrylate: 10 parts by weight (d) “Light Ester” 1 · 10DC (manufactured by Kyoeisha Chemical Co., Ltd.): 8 parts by weight (e) Polyoxypropylenediamine / glycidyl methacrylate / 3 -Glycidoxypropyltrimethoxysilane = 1/3/1 mole of reactant: 2 parts by weight (f) Tri (butoxycarbonylmethyl) trithiophosphite: 2 parts by weight (g) Hindered phenol antioxidant: " Plasanox "1729 (American Cyanamid Co.): 1 part by weight ( ) 4,4 ′-(diethylamino) benzophenone: 2 parts by weight (i) 10-n-butyl-2-chloroacridone: 4 parts by weight (j) 2,4-diethylthioxanthone: 7 parts by weight (k) Dye “ Eisen Victoria Pure Blue "-BOH Conch (Hodogaya Chemical Co., Ltd.): 0.3 parts by weight (l) Surfactant" Florard "FC470 (Sumitomo 3M Co., Ltd.): 0.03 parts by weight (m ) Addition type polymerization inhibitor: 2-ethylanthraquinone: 0.02 parts by weight (n) Ethyl cellosolve: 150 parts by weight (o) Methyl ethyl ketone: 400 parts by weight (p) Tetrahydrofuran: 200 parts by weight.

  From Table 1, it can be seen that the waterless planographic printing plate precursor of the present invention has a good image reproducibility evaluation and excellent long-term storage stability.

Claims (3)

  A waterless lithographic printing plate precursor having at least a radical polymerizable photosensitive layer and an ink repellent layer in this order on a support, and containing an acetophenone polymerization initiator and a triphenylmethane dye in the radical polymerizable photosensitive layer A waterless lithographic printing plate precursor characterized by that.   2. The waterless lithographic printing plate precursor as claimed in claim 1, wherein the radical polymerizable photosensitive layer contains an addition type polymerization inhibitor.   The waterless lithographic printing plate precursor as claimed in claim 2, wherein the addition-type polymerization inhibitor contains an anthraquinone derivative.