JP2010107818A - Developer for negative photosensitive lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer in which the development scums accumulating in a developing tank during development processing are markedly reduced and which attains long-term stable processing, and a developer which improves the developability and the printing durability of a lithographic printing plate using a photosensitive composition. <P>SOLUTION: The developer for a negative photosensitive lithographic printing plate contains an anionic surfactant represented by formula (I) and a chelating agent, wherein the developer contains the anionic surfactant in the range of 1.0-10 mass% and the chelating agent in the range of 0.05-1.0 mass% and has pH of 11-12.5. In the formula (I), R<SB>1</SB>represents a straight chain or a branched chain 1C-5C alkylene; n represents an integer of 3-100; m represents 1, 2 or 3; and M represents a monovalent alkali metal or NH<SB>4</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing solution, and more particularly to a developing solution useful for processing a so-called negative photosensitive lithographic printing plate that can be directly made by scanning a laser based on a digital signal from a computer or the like.

  The development of lasers in recent years has been remarkable, and in particular, high-power and small-sized laser light sources having a light emitting region from near infrared to infrared have become readily available. These lasers are very useful as a recording light source when a printing plate is directly made using digital data from a computer or the like (Computer to Plate: hereinafter abbreviated as CTP). For example, a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 760 nm to 1200 nm are useful because their outputs are higher than those in other wavelength regions. Accordingly, there is a growing demand for image forming materials that are highly sensitive to such lasers, that is, image forming materials that are highly soluble in a developer upon laser irradiation.

  As such an image forming material, an image forming material utilizing a radical addition polymerization reaction has been proposed. Usually, an image is formed by laser exposure for an image and then developing with an alkaline aqueous solution. In that case, there are proposed a method in which heat treatment is performed after exposure and development is performed, and a method in which development is performed immediately after exposure without performing heat treatment. The former has the disadvantage of increasing the size and cost of the equipment because it is necessary to attach an overheating oven to the automatic processor. On the other hand, since the latter does not sufficiently promote radical polymerization by exposure, curing of the exposed portion is difficult to proceed, and as a result, the printing durability is lower than that of the heating type. However, since there is a great merit for users who do not need a heating oven, a non-heating method is expected.

  As a means for imparting sufficient printing durability by the non-heating method, it is desirable to reduce damage to the image area in the development process as much as possible. Further, in order to stably develop the function as a lithographic printing plate, it is required that the solubility difference (discrimination) between the exposed and unexposed areas is large as the development processability. It has been reported that the solubility difference can be improved to some extent by adding a specific surfactant to the developer (for example, see Patent Document 1).

  However, for example, Patent Document 2 discloses a negative photosensitive lithographic printing plate using a thermopolymerizable composition, and a strong alkaline (pH exceeding 12.5) aqueous solution containing potassium silicate or the like is used for development. ing. In order to improve the performance of the developer, it is desirable that the damage to the image area is reduced as described above, and it is important that the developer always maintains a stable activity. In the case of a developer having the above, there is a problem that the image portion is greatly damaged and the printing durability is insufficient. Furthermore, if the development process is continued for a long period of time, the carbon dioxide gas absorption amount of the developer changes due to changes in the environment, for example, carbon dioxide concentration, and the developer activity fluctuates. In addition, the plate material component accumulates in the developing layer, causing problems such as clogging of piping and the like.

On the other hand, the photopolymerizable composition formed on the surface of the glass substrate is developed with, for example, a mixed aqueous solution of sodium carbonate and sodium bicarbonate having a pH of about 10 in order to suppress the deterioration of the development performance due to the use over time and repeatedly. (For example, refer to Patent Document 3 and Patent Document 4). However, when the present inventors applied these developers to a photosensitive lithographic printing plate having a photosensitive layer of a photopolymerizable composition on the surface of an aluminum support, the developability in non-image areas is not sufficient. I could not say it.
In addition, the acid value of the photopolymerizable composition is adjusted for the purpose of providing a lithographic printing plate having sufficient image strength and printing durability by improving the adhesion of the photopolymerizable composition to the support. The invention characterized by doing is reported (refer patent document 5).

JP 2003-43703 A JP-A-8-108621 JP-A-5-88377 JP-A-11-65126 JP 2002-214780 A

  An object of the present invention is to improve the developability and printing durability of a lithographic printing plate using a photosensitive composition, and to significantly reduce the development residue accumulated in the developing bath during the development process. An object of the present invention is to provide a developer that can be stably processed.

（式中、Ｒ_１は直鎖または分岐鎖の炭素原子数１〜５のアルキレン基を表し、ｎは３〜１００までの整数を表し、ｍは１、２又は３を表し、Ｍは１価のアルカリ金属またはＮＨ_４を表す。）また、本発明に係る現像液は、下記式（II)で表わされるアニオン界面活性剤をさらに含むこともできる。

（式中、Ｒ_２は直鎖または分岐鎖の炭素原子数１〜５のアルキレン基を表し、ｎは３〜１００までの整数を表し、Ｍは１価のアルカリ金属またはＮＨ_４を表す。） The developer of the present invention is a developer for a negative photosensitive lithographic printing plate containing an anionic surfactant represented by the following formula (I) and a chelating agent. 0 to 10% by mass and a chelating agent in the range of 0.05 to 1.0% by mass, and the developer has a pH of 11 to 12.5.

(In the formula, R ₁ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, m represents 1, 2 or 3, and M represents a monovalent group. .) also an alkali metal or NH _4, the developer according to the present invention may further comprise an anionic surfactant represented by the following formula (II).

(In the formula, R ₂ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, and M represents a monovalent alkali metal or NH _4. )

（上記式中、Ｒ_３およびＲ_４は、それぞれ独立して水素原子または置換基を有してもよい炭素数１〜１０のアルキル基を表す。また、Ｌ_１およびＬ_２はそれぞれ独立して置換基を有してもよいアルキル基、又は、置換基を有していてもよいアリール基を表す。 Furthermore, the negative photosensitive lithographic printing plate to which the developer of the present invention is applied can contain an infrared absorber, a polymerization initiator, and a polymerizable compound having an ethylenically unsaturated bond. Moreover, this negative photosensitive lithographic printing plate can further contain an alkali-soluble resin having a monomer unit represented by the following formula (III).

(In the above formula, R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent. L ₁ and L ₂ each independently represent The alkyl group which may have a substituent or the aryl group which may have a substituent is represented.

  According to the present invention, by containing a specific amount of a specific anionic surfactant and a chelating agent in the developer in a relatively high pH range of pH 11 to 12.5 with little damage to the photosensitive composition, It has been found that the developability of the non-image area is improved, and sufficient developability, printing durability, and stain resistance can be secured, and further, a compound that is insoluble in mere alkaline water, such as a dye, is solubilized. It was also found that residue precipitation accumulated in the developing bath can be suppressed.

(Developer)
Below, the developing solution of this invention is demonstrated. The developer of the present invention contains a specific anionic surfactant described later in a range of 1.0% by mass to 10% by mass and a chelating agent in a range of 0.05% by mass to 1.0% by mass. A developer for negative photosensitive lithographic printing having a pH of 11 to 12.5.
(1. Anionic surfactant)
The anionic surfactant used in the developer of the present invention is a compound represented by the following formula (I).

（上記式中、Ｒ_１は直鎖または分岐鎖の炭素原子数１〜５のアルキレン基を表し、ｎは３〜１００までの整数を表し、ｍは１、２又は３を表し、Ｍは１価のアルカリ金属またはＮＨ_４を表す。）

(In the above formula, R ₁ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, m represents 1, 2 or 3, and M represents 1) Represents a valent alkali metal or NH _4. )

In a preferred embodiment of the present invention, in the above formula, preferred examples of R ₁ include —CH ₂ —, —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, more preferably —CH _2. CH ₂ — may be mentioned. Moreover, it is preferable that n is an integer of 1-20. M is preferably sodium, potassium, lithium, or NH ₄ .

これらのアニオン界面活性剤は市場で入手することができ、市販品として例えば日本乳化剤株式会社製の商品名、「ニューコール707-SF」、「ニューコール707-SFC」、「ニューコール707-SN」、「ニューコール714-SF」、「ニューコール714-SN」、「ニューコール723-SF」、「ニューコール740-SF」、「ニューコール780-SF」、「ニューコール2607-SF」、「ニューコール2614-SF」などが挙げられる。 Specific examples of the compound represented by the formula (I) include the following compounds.

These anionic surfactants can be obtained on the market. As commercial products, for example, trade names made by Nippon Emulsifier Co., Ltd., “New Coal 707-SF”, “New Coal 707-SFC”, “New Coal 707-SN” ”,“ New Call 714-SF ”,“ New Call 714-SN ”,“ New Call 723-SF ”,“ New Call 740-SF ”,“ New Call 780-SF ”,“ New Call 2607-SF ”, For example, “New Call 2614-SF”.

The above compounds may be used alone or in combination of two or more. The addition amount of the compound is suitably 1.0% by mass to 10% by mass in the developer, and it is effective to add 2.0% by mass to 10% by mass.
Here, if the addition amount is less than 1.0% by mass, the developability and the solubility of the photosensitive layer components are lowered, and if it exceeds 10% by mass, the developability becomes excessive and the printing durability of the printing plate is lowered.

  The developer of the present invention may contain an anionic surfactant represented by the following formula (II).

（上記式中、Ｒ_２は直鎖または分岐鎖を有する炭素原子数１〜５のアルキレン基を表し、ｎは３〜１００までの整数を表し、Ｍは１価のアルカリ金属またはＮＨ_４を表す。）

(In the above formula, R ₂ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, and M represents a monovalent alkali metal or NH ₄ . .)

Preferred examples of _{R 2} in the _{formula, -CH 2 -, - CH 2} CH 2 -, - CH 2 CH 2 CH 2 - and the like, more preferably _-CH 2 CH ₂ - include. Moreover, it is preferable that n is an integer of 1-20. M is preferably sodium, potassium, lithium, or NH ₄ .
Specific examples of the compound represented by the general formula (II) include the following compounds, but are not limited thereto.

  You may contain the said compound individually or in combination of 2 or more. The amount of the compound added is preferably 1.0 to 10% by mass, more preferably 2.0 to 10% by mass in the developer.

Examples of other surfactants that can be contained in the developer of the present invention include polyoxyethylene naphthyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and polyoxyethylene. Polyoxyethylene alkyl ethers such as ethylene stearyl ether, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan Nonio such as sorbitan alkyl esters such as trioleate, glycerol monostearate, glycerol monooleate and glyceride alkyl esters A surfactant.
These surfactants can be used alone or in combination. Further, the content of these surfactants in the developer is preferably from 0.1% by mass to 10% by mass.

(2. Chelating agent)
The developer of the present invention can contain a chelating agent. Particularly preferred as the chelating agent contained in the developer of the present invention is a chelating agent for a divalent metal.
Examples of divalent metals include magnesium and calcium. Examples of the chelating agent for the divalent metal include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , Polyphosphates such as calgon (sodium polymetaphosphate) such as ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt, triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt , Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt, nitrilotriacetic acid, its potassium salt, its sodium salt, 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt, 1,3-diamino-2 -Propanol tetraacetic acid In addition to aminopolycarboxylic acids such as potassium salt and sodium salt thereof, 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salt thereof, sodium salt thereof, 2-phosphonobutanone tricarboxylic acid-2,3 , 4, its potassium salt, its sodium salt, 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, its sodium salt, aminotri (methylenephosphonic acid), its potassium salt, its sodium salt, etc. Mention may be made of phosphonic acids. The optimum amount of such a chelating agent varies depending on the hardness of the hard water used and the amount used, but it is 0.05 to 1.0% by weight, more preferably 0.8% by weight in the developer at the time of use. It is made to contain in the range of 05 mass%-0.5 mass%.
If the addition amount is less than 0.05% by mass, the printing plate is soiled. On the other hand, if it exceeds 1.0% by mass, the developability is lowered and the solubility of the photosensitive layer components is lowered.

  In addition to the above components, the following components can be used in combination in the developer of the present invention as necessary. For example, benzoic acid, phthalic acid, p-ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, p-2-hydroxyethylbenzoic acid Organic carboxylic acids such as acid, decanoic acid, salicylic acid, 3-hydroxy-2-naphthoic acid, organic solvents such as isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol, and others Antifoaming agents, alkali metal salts of organic acids, alkali metal salts of inorganic acids, reducing agents, dyes, pigments, preservatives, and the like can be used in combination.

A commercially available silicone antifoaming agent can be used as the silicone antifoaming agent. For example, KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.), TSA737 (manufactured by GE Toshiba Silicone Co., Ltd.), FS Anti Home 544 (manufactured by Toray Dow Corning Co., Ltd.), FS Anti Home 90 (manufactured by Toray Dow Corning Co., Ltd.) ) And the like.
Specific examples of the alcohol-based antifoaming agent include methanol, ethanol, butanol and the like.
Specific examples of the nonionic surfactant system include sorbitan acid fatty acid ester and acetylene glycol. For example, Pronal C-448 (manufactured by Toho Chemical Industry Co., Ltd.), Pronal EX-300 (manufactured by Toho Chemical Industry Co., Ltd.), Neoclaire TO-1 (manufactured by Takemoto Yushi Co., Ltd.), Neo Klenol TO-2 (Takemoto Yushi Co., Ltd.) ), Acetylenol EL (manufactured by Kawaken Fine Chemical Co., Ltd.), acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.), acetylenol E40 (manufactured by Kawaken Fine Chemical Co., Ltd.), acetylenol E100 (manufactured by Kawaken Fine Chemical Co., Ltd.), Surfynol 61 (Air Products Japan Co., Ltd.), Surfinol 82 (Air Products Japan Co., Ltd.), Surfinol 104 (Air Products Japan Co., Ltd.), Surfynol DF-110 (Air Products Japan Co., Ltd.), etc. .
The addition amount of the antifoaming agent is preferably 0.00001% by mass or more, more preferably about 0.0001% by mass to 0.5% by mass with respect to the developer mass.

  Examples of alkali metals of organic acids and alkali metal salts of inorganic acids include sodium carbonate, potassium, ammonium, sodium citrate, potassium, ammonium and the like.

  Examples of alkaline agents include inorganic alkaline agents such as tribasic sodium phosphate, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, potassium, ammonium and lithium, monomethylamine, dimethyl Amine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolanolamine, ethyleneimine, ethylenediamine , Organic alkaline agents such as pyridine and tetramethylammonium hydroxide.

  The alkali silicate is alkaline when dissolved in water, and examples thereof include sodium silicate, potassium silicate, lithium silicate, and ammonium silicate.

The developer of the present invention comprises silicon oxide SiO ₂ which is a component of silicate as a hydrophilic component with the substrate, and alkali oxide M ₂ O (M represents an alkali metal or ammonium group) as an alkali component. By adjusting the mixing ratio and concentration, it is possible to easily adjust to the optimum range. A preferable mixing ratio (SiO ₂ / M ₂ O molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O is 0.75 to 4.0, preferably 0.75 to 3.5. is there.
When the SiO ₂ / M ₂ O is less than 0.75, the alkalinity becomes strong, the anodized film of the aluminum substrate as the support of the photosensitive lithographic printing plate is excessively dissolved (etched), and the left stain is removed. Or when an insoluble residue due to complex formation between dissolved aluminum and silicic acid occurs, and if SiO ₂ / M ₂ O exceeds 4.0 or more than 3.5, the developability decreases or the silicate There may be a problem that condensed insoluble residue is generated.

The concentration of the alkali silicate in the developer is preferably in the range of 0.01 to 1 mol / L as SiO _{2 with} respect to the total mass of the developer, more preferably 0.05 to 0. Within the range of 8 mol / L. If this concentration is less than 0.01 mol / L, the effect of inhibiting dissolution (etching) of the anodized film on the aluminum substrate cannot be obtained, and the developability and development processing ability may be reduced. As a result of facilitating the formation of precipitates and crystals, and facilitating gelation during neutralization of the waste liquid, the waste liquid treatment may be hindered.

  The pH of the developer of the present invention is essential to be 10 to 12.5, and preferably 11 to 12.5. Moreover, it is essential that the electrical conductivity x is 2 <x <30 mS / cm, and it is preferable that it is 5-25 mS / cm.

  Further, as a conductivity adjusting agent, an alkali metal salt of an organic acid or an alkali metal salt of an inorganic acid can be added to adjust the conductivity.

  The developer of the present invention can be used as a developer and a developer replenisher for the exposed negative photosensitive composition and is preferably applied to an automatic processor. When developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. The replenishment method is also preferably applied to the image forming method using the developer of the present invention.

The developer of the present invention is preferably used for a negative photosensitive lithographic printing plate because the effect is particularly remarkable. The composition for forming the photosensitive layer of the negative photosensitive lithographic printing plate contains an infrared absorber, a polymerization initiator, and a polymerizable compound having an ethylenically unsaturated bond, and is an alkali-soluble resin or an alkali-soluble resin. It is more preferable to further contain a resin and a silane coupling agent.
Below, the negative photosensitive composition in which the developing solution of this invention is used suitably is demonstrated in detail.

(Infrared absorber)
The infrared absorber has a function of converting absorbed infrared rays into heat. With the heat generated by this conversion, a polymerization initiator (radical generator) described later is thermally decomposed to generate radicals. The infrared absorbing dye contained in the infrared absorber used in the negative photosensitive composition has an absorption maximum at a wavelength of 650 nm to 1300 nm, preferably an absorption maximum and a molar extinction coefficient ε of 10 ⁵ or more. Infrared absorbing dyes are particularly effective.

  Infrared absorbing dyes include cyanine dyes, squarylium dyes, croconium dyes, azurenium dyes, phthalocyanine dyes, naphthalocyanine dyes, polymethine dyes, naphthoquinone dyes, thiopyrylium dyes, dithiol metal complex dyes, anthraquinones System dyes, indoaniline metal complex dyes, and intermolecular CT dyes.

  Further, for example, infrared absorbing dyes are described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-7878, and the like. Cyanine dyes, methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, JP-A 58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., Examples thereof include squarylium dyes described in JP-A No. 58-112792, and cyanine dyes described in US Pat. No. 434,875.

  In addition, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted arylbenzos described in US Pat. No. 3,881,924 ( Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-220143 Disclosed in Japanese Patent Laid-Open Nos. 59-41363, 59-84248, 59-84249, 59-146061, and 59-146063. Pyryllium compounds, cyanine dyes described in JP-A-59-216146, pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, etc. 5-13514, JP-pyrylium compounds disclosed in JP-A-5-19702 are also preferably used. Further, as another preferred example of the dye, there can be mentioned infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993.

Although these pigment | dyes can be synthesize | combined by a well-known method, the following commercial items can also be used.
Nippon Kayaku Co., Ltd .: IR750 (anthraquinone), IR002, IR003 (aluminum), IR820 (polymethine), IRG022, IRG033 (diimonium), CY-2, CY-4, CY-9, CY-10, CY-20
Dainippon Ink & Chemicals, Inc .: Fastogen blue 8120
Midori Chemical Co., Ltd .: MIR-101, MIR-1011, MIR-1021
In addition, the above dyes are also commercially available from Nippon Photosensitive Co., Ltd., Mitsui Chemicals, Showa Denko, and Fuji Film Co., Ltd.

（式中、Ｒ_５およびＲ_６はそれぞれ独立して水素原子または置換基を有してもよいアルキル基またはアルコキシ基を表し、Ｒ_７およびＲ_８はそれぞれ独立して置換基を有してもよいアルキル基またはアルコキシ基を表し、Ｘは電位中和イオンを表し、ｎは１〜７の整数を表す。） Among the infrared absorbing dyes, an infrared absorbing dye represented by the following formula (A) is particularly preferable.

(In the formula, R ₅ and R ₆ each independently represent a hydrogen atom or an alkyl group or an alkoxy group which may have a substituent, and R ₇ and R ₈ may each independently have a substituent. Represents a good alkyl group or alkoxy group, X represents a potential neutralization ion, and n represents an integer of 1 to 7.)

  Specific examples ([A-1] to [A-4]) of the infrared absorber represented by the general formula (A) that can be suitably used are listed below, but are not limited thereto. .

  The addition amount of the infrared absorber containing the infrared absorbing dye is 0.5% by mass to 10% by mass, preferably 0.6% by mass to 8.0% by mass with respect to the total weight of the photosensitive composition. . When the addition amount is 0.5% by mass or more, particularly 0.6% by mass or more, the sensitivity is high, and when it is 10% by mass or less, particularly 8.0% by mass or less, the developability of the non-image area (unexposed area) is high. Since it improves, it is preferable.

(Polymerization initiator)
The negative photosensitive composition can contain a polymerization initiator that generates radicals by light or heat in order to initiate and advance the curing reaction of the polymerizable compound described below. As the polymerization initiator, it is preferable to contain an organic boron salt polymerization initiator which is a thermal decomposition type radical generator that generates radicals by being decomposed by heat.
Further, by using an organic boron salt polymerization initiator in combination with the above-described infrared absorber, the infrared absorber generates heat when irradiated with an infrared laser, and radicals can be generated by the heat. Since these combinations enable high-sensitivity heat mode recording, such combinations are preferable.

  Examples of the organic boron salt polymerization initiator suitably used include organic boron anions represented by the following general formula (B).

（式中、Ｒ_９、Ｒ_１０、Ｒ_１１、およびＲ_１２は、それぞれ同じでも異なっていてもよく、アルキル基、アリール基、アラルキル基、アルケニル基、アルキニル基、シクロアルキル基、複素環基を表す。これらのうちでＲ_９、Ｒ_１０、Ｒ_１１、およびＲ_１２の内１つがアルキル基であり、他の置換基がアリール基である場合が特に好ましい。）

(Wherein R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ may be the same or different, and each represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, or a heterocyclic group. Among them, it is particularly preferred that one of R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ is an alkyl group and the other substituent is an aryl group.)

  Examples of the cation constituting the organoboron salt include alkali metal ions and onium compounds, preferably onium salts such as ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonyl salts, and triaryls. Examples thereof include alkylphosphonium salts.

  Specific examples ([OB-1] to [OB-6]) of organic boron salts represented by the general formula (B) that can be suitably used are shown below, but are not limited thereto.

In addition to the organic boron salt polymerization initiator, other polymerization initiators (other radical generators) can be used in combination.
Other radical generators include onium salts other than organic boron salts, trihaloalkyl-substituted compounds, and sulfonium salts.

  The trihaloalkyl-substituted compound is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. Preferable examples include s-triazine derivatives and oxazole derivatives as compounds in which the trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group, or the trihaloalkyl group is an aromatic ring or nitrogen-containing heterocyclic ring via a sulfonyl group. And a trihaloalkylsulfonyl compound bonded to.

  Specific examples ([T-1] to [T-14], [BR-1] to [BR-10]) of trihaloalkylsulfonyl compounds that can be suitably used are shown below, but are limited thereto. It is not a thing.

Examples of other onium salts include sulfonium salts represented by the following formula (C).

In the formula (C), R ₁₃ , R ₁₄ , and R ₁₅ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. Z ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchlorate ion, hexa Fluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

  Specific examples ([OS-1] to [OS-10]) of onium salts represented by the formula (C) that can be suitably used are shown below, but are not limited thereto.

  The polymerization initiator (radical generator) as described above preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. Thus, the photosensitive lithographic printing plate can be handled under white light by setting the absorption wavelength in the ultraviolet region.

  The content of the polymerization initiator in the photosensitive composition is preferably 1% by mass to 40% by mass, more preferably 1% by mass to 20% by mass with respect to the alkali-soluble resin contained in the photosensitive composition. It is. When the content is less than 1% by mass, the sensitivity tends to be low, and when it exceeds 40% by mass, smearing tends to occur in non-image areas during printing when applied to a photosensitive lithographic printing plate.

  The polymerization initiator in the photosensitive composition is particularly preferably one containing an organic boron salt polymerization initiator or a trihaloalkyl compound, and only one organic boron salt polymerization initiator or trihaloalkyl compound may be used. More than one species may be used in combination.

(Polymerizable compound)
The polymerizable compound used in the negative photosensitive composition is an addition polymerizable compound having at least one ethylenically unsaturated bond, and is a compound having at least one ethylenically unsaturated bond, preferably two or more. To be elected. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof, and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  The polymerizable compound having an ethylenically unsaturated bond can be synthesized by a known method, or a commercially available compound can be used.

  The polymerizable compound used in the photosensitive composition is contained from the viewpoint of improving film properties, and various compounds can be used as long as they have a function of improving film properties. Content of the polymeric compound in a photosensitive composition is 5.0 mass%-70 mass% with respect to the alkali-soluble resin mentioned later, More preferably, it is 10 mass%-60 mass%. In the case of 5.0% by mass or more, particularly 10% by mass or more, a tough and highly flexible image can be obtained when an image is formed. 70% by mass or less, particularly 60% by mass or less, is preferable because it is easy to dissolve in an alkaline aqueous solution, the development speed is high, and the sensitivity is not slowed down.

  About the polymerizable compound in the photosensitive composition, details of the usage method such as its structure, single use or combination, addition amount and the like can be arbitrarily set according to the final performance design. For example, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether). The method of adjusting both photosensitivity and strength is also effective by using a compound of a compound type) together. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in photosensitive speed and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components in the composition (for example, binder polymer, initiator, colorant, etc.). In some cases, the compatibility can be improved by using a low-purity compound or using two or more of them together.

（上記式中、Ｒ_３およびＲ_４は、それぞれ独立して水素原子または置換基を有してもよい炭素数１〜１０のアルキル基を表す。また、Ｌ_１およびＬ_２はそれぞれ独立して置換基を有してもよいアルキル基、又は、置換基を有していてもよいアリール基を表す。）
アルカリ可溶性樹脂は、上記式（III）の構造式を有する重合性化合物の重合により得られる共重合体である。上記式（III）の単量単位を有する重合性化合物は、例えば、アルコール性水酸基を有する重合性化合物と不飽和二重結合を有するイソシアネート化合物との付加反応から得ることができる。 (Alkali-soluble resin)
Moreover, it is preferable that the photosensitive composition contains an alkali-soluble resin having a monomer unit represented by the following formula (III).

(In the above formula, R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent. L ₁ and L ₂ each independently represent Represents an alkyl group which may have a substituent or an aryl group which may have a substituent.
The alkali-soluble resin is a copolymer obtained by polymerization of a polymerizable compound having the structural formula of the above formula (III). The polymerizable compound having a monomer unit of the above formula (III) can be obtained, for example, from an addition reaction between a polymerizable compound having an alcoholic hydroxyl group and an isocyanate compound having an unsaturated double bond.

  Content of the polymeric compound which has structural formula of a formula (III) is 5-70 mass% with respect to alkali-soluble resin, More preferably, it is 10-60 mass%. In the case of 5% by mass or more, particularly 10% by mass or more, a tough and highly flexible image can be obtained when an image is formed. 70 mass% or less, particularly 60 mass% or less, is preferable because it is easy to dissolve in an alkaline aqueous solution and the development speed is not increased and the sensitivity is not decreased.

Examples of the other monomer having a polymerizable unsaturated bond group that is added as necessary together with the polysynthetic compound represented by the above formula (III) include, for example, monomers listed in the following (1) to (10) Is preferred.
(1) Monomers having a phenolic hydroxyl group such as N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, p-isopropenylphenol, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, and p-hydroxyphenyl methacrylate.
(2) Monomers having a sulfonamide group such as m-aminosulfonyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, and N- (p-aminosulfonylphenyl) acrylamide.
(3) Monomers having an active imide group such as N- (p-toluenesulfonyl) methacrylamide and N- (p-toluenesulfonyl) acrylamide.
(4) Monomers having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 2-hydroxy-3-phenoxypropyl methacrylate.
(5) α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid and maleic anhydride.
(6) Monomers having an allyl group such as acrylic methacrylate and N-acrylmethacrylamide.
(7) Alkyl acrylates or alkyl methacrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, glycidyl acrylate, methyl methacrylate Ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, glycidyl methacrylate.
(8) Acrylamides or methacrylamides such as acrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N -Phenylacrylamide, methacrylamide, N-methylol methacrylamide, N-ethyl methacrylamide, N-hexyl methacrylamide, N-cyclohexyl methacrylamide, N-hydroxyethyl methacrylamide, N-phenyl methacrylamide.
(9) Styrenes such as styrene, α-methylstyrene, chloromethylstyrene and the like.
(10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.
These monomers may be used alone or in combination of two or more compounds of the same group of (1) to (10) or in combination of two or more compounds of different groups. Good.
The other monomer content added as necessary is preferably 1% by mass to 40% by mass and more preferably 5% by mass to 40% by mass with respect to the alkali-soluble resin.

  There is no restriction | limiting in particular about the manufacturing method of alkali-soluble resin, It can manufacture similarly to the manufacturing method of a normal vinyl type or an acryl-type polymeric compound. For example, a desired copolymer can be obtained by dissolving each monomer component in an appropriate solvent, adding a conventionally used radical polymerization initiator, and performing polymerization by heating as necessary. The copolymer thus obtained has a polystyrene calculated weight average molecular weight of 10,000 to 200,000, preferably 20,000 to 100,000, as measured by gel permeation chromatography (GPC). If the polymerization average molecular weight is less than 10,000, the image portion is likely to swell and the mechanical strength is insufficient. If it exceeds 200,000, it is not preferable because stains due to poor development are likely to occur.

  Examples of the solvent used for the polymerization of the copolymer include methyl cellosolve, propylene glycol monomethyl ether, dioxane, methyl ethyl ketone, cyclohexanone, N, N-dimethylformamide, N, N-dimethylacetamide and the like. Examples of the radical polymerization initiator used for polymerization of the polymerizable compound include 2,2′-azobis (2-methylbutyronitrile), benzoin peroxide and the like. As addition amount, it is 0.1 mass%-1.0 mass% with respect to the whole quantity of a monomer.

  Moreover, the copolymer used may be used independently and may be used together 2 or more types. For example, a polymerizable compound of an acrylic acid derivative is preferable among them. The polymerizable compound of the acrylic acid derivative is an acrylic acid polymerizable compound having a side chain carboxyl group, and an alkali-soluble polymerizable compound having an ethylenically unsaturated bond at the terminal by addition reaction of glycidyl methacrylate with the carboxyl group Is preferred.

  The introduction rate of glycidyl methacrylate is 20 to 70%, more preferably 30 to 60%, based on the carboxyl group in the copolymer. When the introduction rate is less than 20%, the sensitivity may be significantly lowered, and when the introduction rate is 70% or more, the developability may be deteriorated.

  The Mw of the polymerizable compound of the acrylic acid derivative is preferably 1,000 to 500,000, particularly preferably 1,500 to 300,000. When Mw is 1,000 or more, particularly 1,500 or more, a particularly sufficient coating film can be obtained. Can be developed.

  Although it is not particularly limited, in the photosensitive composition, as a polyurethane resin that is preferably further contained, the glass transition temperature (Tg) of the polymer is 50 ° C to 180 ° C, more preferably 70 ° C to 150 ° C. It is a range. When Tg is less than 50 ° C., film formability, that is, a uniform surface of the photosensitive layer may be difficult to form, and surface stickiness may easily occur. When Tg exceeds 180 ° C., alkali solubility becomes worse and development failure tends to occur, which is not preferable. Here, in this specification, the glass transition temperature (Tg) was measured using a differential scanning calorimeter DSC-60 (Shimadzu Corporation). The average molecular weight (Mw) of the polyurethane resin is not particularly limited, and any conventionally used polyurethane resin can be used.

  Generally, the alkali-soluble polyurethane resin is a polyurethane resin having a carboxyl group in a side chain as described in JP-A No. 2002-311579, and an addition reaction of glycidyl methacrylate with the carboxyl group is performed at the terminal. An alkali-soluble polyurethane resin having an ethylenically unsaturated bond is particularly desirable.

  Moreover, when synthesizing an alkali-soluble polyurethane resin having an ethylenically unsaturated bond at a preferable terminal, the diisocyanate compounds preferably used include those shown below. That is, as the diisocyanate compound, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3- Dimethylbiphenyl-4,4-diisocyanate, hexamethylene diisocyanate, trimethylhexanemethylene diisocyanate, lysine diisocyanate, isophorodiisocyanate, 4,4-methylenebis (cyclohexyl isocyanate), methylcyclohexyl-2,4- (or 2,6-) diisocyanate 1,3-bis (isocyanatomethyl) cyclohexane and the like.

  Specific examples of the diol compound having a carboxyl group of the alkali-soluble polyurethane resin include those shown below. That is, as a diol compound having a carboxyl group, 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxypropyl) propionic acid, N, N-2,2- Examples include dihydroxyethyl glycine, bis (hydroxymethyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, tartaric acid and the like.

  Moreover, the diol compound which does not have a carboxyl group and may have the other substituent which does not react with isocyanate can also be used, Specifically, what is shown below is included. That is, as a diol compound, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, polyester polyol, polycarbonate diol, neopentyl glycol, 1,3-butylene glycol, 1,6- Hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, Ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol F, bis Enol F propylene oxide adduct, hydrogenated bisphenol A ethylene oxide adduct, hydrogenated bisphenol A propylene oxide adduct, hydroquinone dihydroxyethyl ether, p-xylene glycol, dihydroxyethyl sulfone, bis- (2-hydroxyethyl) Examples include -2,4-tolylene dicarbamate and bis (2-hydroxyethyl) isophthalate.

  An alkali-soluble polyurethane resin having an ethylenically unsaturated bond at the terminal can be synthesized by a two-step reaction, which is a polyurethane resin having a side chain carboxyl group, which is obtained by adding glycidyl methacrylate to the carboxyl group. . First, a polyurethane resin as a basic skeleton is obtained by using a known catalyst having an activity corresponding to the reactivity of the diisocyanate compound, the diol compound having a carboxyl group and the diol compound not having a carboxyl group in an aprotic solvent. It can be synthesized by adding and heating. Next, the alkali-soluble polyurethane resin can be synthesized by addition reaction of glycidyl methacrylate with the obtained polyurethane as the basic skeleton. The molar ratio of the diisocyanate compound and the diol compound to be used is preferably 0.8: 1 to 1.2: 1. When an isocyanate group remains at the polymer terminal, it is treated with an alcohol or an amine. Finally, it is synthesized in a form in which no isocyanate group remains.

  The introduction rate of glycidyl methacrylate is 20 to 70%, more preferably 30 to 60%, based on the carboxyl group in the polyurethane that is the basic skeleton in the first stage. If the introduction ratio is less than 20%, the effect of high printing durability may be difficult, and if the introduction ratio exceeds 70%, the developability may deteriorate.

（式中Ｒ_１６〜Ｒ_１８は、それぞれ独立して水素原子、置換基を有してもよいアルキル基またはアルコキシ基を示す。Ｘは、エステル結合、アミド結合又はフェニル基を示す。Ｚは、０または１を示す。Ｙは、０〜１０の整数を示す。）
上記アルカリ可溶性樹脂および上記シランカップリング剤を含有する感光層は、レーザー等によって照射されると、上記アルカリ可溶性樹脂中の特定不飽和二重結合部位と上記シランカップリング剤中の不飽和二重結合部位との高速重合によって、非常に高密度な架橋構造と有することができる。 Moreover, it is preferable that the photosensitive composition contains the silane coupling agent represented by Formula (IV) with alkali-soluble resin.

(In the formula, R _{16 to} R ₁₈ each independently represents a hydrogen atom, an alkyl group or an alkoxy group which may have a substituent. X represents an ester bond, an amide bond or a phenyl group. Z represents Represents 0 or 1. Y represents an integer of 0 to 10.)
When the photosensitive layer containing the alkali-soluble resin and the silane coupling agent is irradiated with a laser or the like, the specific unsaturated double bond site in the alkali-soluble resin and the unsaturated double bond in the silane coupling agent are used. By high-speed polymerization with a binding site, it can have a very high density cross-linked structure.

  The content of the silane coupling agent represented by the formula (IV) is preferably 15 to 40% by mass, more preferably 20 to 40% by mass with respect to the total mass of the photosensitive composition. When the content is 15% by mass or more, printing durability and chemical resistance are particularly improved. On the other hand, if it is 10% by mass or less, the printing durability and chemical resistance deteriorate.

  In addition, when the photosensitive composition is applied to a photosensitive lithographic printing plate, a specific structure may be selected for the purpose of improving the adhesion of a support or an overcoat layer described later.

  In addition, the use method of the addition polymerizable compound can arbitrarily select an appropriate structure, blending, and addition amount from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface adhesiveness, and the like.

  In addition to the above basic components, other components suitable for the application, production method, and the like can be appropriately added to the photosensitive composition. Hereinafter, it illustrates about a preferable additive.

(Polymerization inhibitor)
In the photosensitive composition, it is preferable to add a small amount of a thermal polymerization inhibitor in order to inhibit unnecessary thermal polymerization of a polymerizable compound having an ethylenically unsaturated bond, that is, a polymerizable compound. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pingarol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like can be mentioned. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the nonvolatile components in the entire composition. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition due to oxygen, and it may be unevenly distributed on the surface of the photosensitive layer in the course of drying after coating. . The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass with respect to the nonvolatile components in the entire composition.

(Coloring agent)
Furthermore, you may add dye to the photosensitive composition for the purpose of the coloring. Thereby, so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring machine as a printing plate can be improved. As the colorant, oil-soluble dyes and basic dyes are preferable. Specific examples include Crystal Violet, Malachite Green, Victoria Blue, Methylene Blue, Ethyl Violet, Rhodamine B, Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Oil Blue 613 (Orient Chemical Industry Co., Ltd.), Oil Green Etc. The addition amount of these dyes is preferably 0.05% by mass to 5.0% by mass, more preferably 0.1% by mass to 4.0% by mass, based on the photosensitive composition. When the content is 0.05% by mass or more, particularly 0.1% by mass or more, the photosensitive layer is sufficiently colored, and the image is particularly easy to see. This is preferable because the dye residue hardly remains in the image area.

(Other additives)
Furthermore, you may add well-known additives, such as the inorganic filler for improving the physical property of a cured film, other plasticizers, and the fat sensitive agent which can improve the ink inking property of the photosensitive layer surface. Examples of plasticizers include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin, and addition polymerization with binder polymer. In general, it can be added in a range of 10% by mass or less with respect to the total mass with the active compound. Further, in the photosensitive lithographic printing plate described later, a UV initiator, a thermal cross-linking agent, or the like for enhancing the effect of heating / exposure after development for the purpose of improving the film strength (printing durability) can be added.

  The negative photosensitive composition described above can be suitably used as a photosensitive layer in a photosensitive lithographic printing plate described below.

(Photosensitive lithographic printing plate)
The photosensitive lithographic printing plate is obtained by sequentially laminating a photosensitive layer and optionally a protective layer on a support, and the photosensitive layer contains the above-described photosensitive composition. Such a photosensitive lithographic printing plate is coated on a suitable support or intermediate layer by dissolving a photosensitive layer coating solution containing the photosensitive composition described above or a coating layer component of a desired layer such as a protective layer in a solvent. Can be manufactured.

(Photosensitive layer)
The photosensitive layer is a negative photosensitive layer corresponding to the photosensitive composition described above, and the polymerization initiator is decomposed by light or heat to generate radicals, and the generated radicals cause a polymerization reaction. It has a mechanism. The photosensitive lithographic printing plate having these photosensitive layers is particularly suitable for plate making by direct drawing with a laser beam having a wavelength of 300 nm to 1200 nm, and has a higher printing durability and higher printing durability than conventional photosensitive lithographic printing plates. It has the feature of developing image forming properties.

  When coating the photosensitive layer, the above-described photosensitive composition is dissolved in various organic solvents and coated on the support or the intermediate layer. Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol dimethyl ether. Propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxy Ethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethyl Le formamide, dimethyl sulfoxide, .gamma.-butyrolactone, methyl lactate and ethyl lactate. These solvents can be used alone or in combination. And, the concentration of the solid content in the coating solvent is suitably 2% by mass to 50% by mass.

The coating amount of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the developability, the strength and printing durability of the exposed film, and is preferably selected as appropriate according to the application. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. As the photosensitive lithographic printing plate for scanning exposure which is the main object of the present invention, the coating amount is suitably in the range of about 0.1 g / m ² to about 10 g / m ² in terms of the mass after drying. More preferably from ^{0.5g / m 2 ~5g / m 2} .

(Support)
As the support for the above-described photosensitive lithographic printing plate, a conventionally known hydrophilic support for use in a photosensitive lithographic printing plate can be used without limitation.
The support used is preferably a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc). , Copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), above For example, paper or plastic films laminated or vapor-deposited with metals such as these, and appropriate known physical and chemical treatments for the purpose of imparting hydrophilicity and improving strength as necessary. May be applied.

  In particular, preferable supports include paper, polyester film or aluminum plate, among which dimensional stability is good, relatively inexpensive, and a surface having excellent hydrophilicity and strength by surface treatment as required. An aluminum plate that can be provided is more preferred. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

(Roughening treatment)
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Electrochemical surface roughening method in which the surface is further electrochemically roughened in hydrochloric acid or nitric acid electrolytic solution, and the wire brush grain method in which the aluminum surface is scratched with a metal wire, and the aluminum surface is grained with a polishing ball and an abrasive. A mechanical roughening method such as a grain method or a brush grain method in which a surface is roughened with a nylon brush and an abrasive can be used, and the above roughening methods can be used alone or in combination. Among them, a method usefully used for roughening is an electrochemical method in which roughening is chemically performed in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity during anode is 50 C / dm ^{2 to} 400 C / dm ² . It is a range. Further, specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, at a current density of 100C ^/ dm ² ~400C ^/ dm 2 It is preferable to perform alternating current and / or direct current electrolysis.

  The roughened aluminum substrate may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, and the like. Preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C. Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123. After the treatment as described above, the method conditions are not particularly limited as long as the center line average roughness Ra of the treatment surface is 0.2 to 0.5 μm.

(Anodizing treatment)
The aluminum substrate on which the oxide layer processed as described above is formed is then anodized.
In the anodizing treatment, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid or boric acid / sodium borate is used alone or in combination of a plurality of kinds as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, ions of metals such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and ammonium. Examples of the ions include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions, and the like, and the concentration is 0 to About 10,000 ppm may be contained. Although there is no particular limitation on the conditions for the anodic oxidation treatment, preferably 30 to 500 g / liter, with a processing solution temperature of 10 to 70 ° C., the direct current or alternating current electrolysis in a range of current density 0.1A ^{/ m 2} ~40A ^/ m 2 It is processed. The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. The support prepared by the above treatment is treated so that the pore diameter of the micropores existing in the anodized film is in the range of 5 nm to 10 nm and the pore density is in the range of 8 × 10 ¹⁵ to 2 × 10 ¹⁶ pieces / m ^2. Conditions can be selected.

A widely known method can be applied as the hydrophilic treatment on the surface of the support. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. Coating Si, or P element amount as ^{2mg / m 2 ~40mg / m 2} , and more preferably is formed of a ^{4mg / m 2 ~30mg / m 2} . The coating amount can be measured by fluorescent X-ray analysis.

  Specifically, the above hydrophilization treatment includes alkali metal silicate or polyvinylphosphonic acid in the range of 1 to 30% by mass, preferably 2 to 15% by mass, and the pH at 25 ° C. is 10 to 10%. For example, the aluminum substrate on which the anodized film is formed is immersed in the aqueous solution No. 13 at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or a group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass in the treatment liquid, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. A surface treatment in which an electrolytic grained support as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 is combined with the above-described anodizing treatment and hydrophilic treatment. Is also useful.

[Protective layer (overcoat layer)]
A protective layer is preferably provided on the photosensitive layer described above. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer to allow exposure in the atmosphere. To do. Basically, it is provided to protect the photosensitive layer, but when the photosensitive layer has a radical polymerizable image forming mechanism, it has a role as an oxygen blocking layer and is exposed by a high-intensity infrared laser. Serves as an anti-ablation layer.
In addition to the properties desired for the protective layer, in addition to the above, the transmission of light used for exposure is not substantially inhibited, it has excellent adhesion to the photosensitive layer, and can be easily removed in the development process after exposure. Is desirable. Such a protective layer has been conventionally devised and described in detail in US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinylpyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol that can be used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit that has the necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components.
Specific examples of polyvinyl alcohol include those that are hydrolyzed by 71 to 100% and have a polymerization repeating unit in the range of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, manufactured by Kuraray Co., Ltd. PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like.

  The components of the protective layer (selection of PVA, use of additives), coating amount, etc. are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of unsubstituted vinyl alcohol units in the oxygen barrier layer), the thicker the film, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. is there. However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure. In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic polymer layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization.

As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Number of anionic surfactants such as sodium acid, amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates, and nonionic surfactants such as polyoxyethylene alkylphenyl ethers relative to (co) polymers Mass% can be added.
The thickness of the protective layer is suitably from 0.5 to 5 μm, particularly preferably from 0.5 to 2 μm.

  In addition, it improves the detachability between plates when stacking a large number of lithographic printing plates without interleaving paper, and also improves the detachability between interleaving paper and plate even when interleaving the interleaving paper. In order to do this, the lithographic printing plate may be matted. As a method of matting the surface of the protective layer, a method of adding a matting agent or the like in the protective layer, a method of spray-coating a solution in which a water-soluble resin or a water-soluble resin and a matting agent are dissolved and dispersed on the surface of the protective layer and so on. Examples of the matting agent include silicon dioxide, titanium oxide, alumina powder, starch, starch, polymer particles (for example, particles such as polyacrylic acid and polystyrene), and the like.

  In addition, adhesion to the image area and scratch resistance are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on a new oil-based polymer layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is added to a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing ˜60 mass% and laminating on the polymerized layer. Any of these known techniques can be applied to the protective layer. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and JP-B-55-49729.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
[Photosensitive lithographic printing plate 1]

<Surface treatment>
The aluminum (material 1050) having a thickness of 0.24 mm was degreased with alkali, then the surface was polished with a nylon brush while applying a water suspension of palmiston, and washed thoroughly with water. Subsequently, 70 degreeC and 15 weight% sodium hydroxide aqueous solution was poured over 5 second, and the surface was etched 3g / m < ² >, Then, it washed with water further. Next, an electrolytic surface roughening treatment was performed at 200 C / dm ² in a 1N hydrochloric acid bath. Subsequently, after washing with water, the surface was etched again with a 15% by weight aqueous sodium hydroxide solution, washed with water, then immersed in a 20% by weight aqueous nitric acid solution and desmutted. Next, anodization was performed in a 15% by weight sulfuric acid aqueous solution to form a 2.0 g / m ² oxide film. After washing with water, 1% by weight potassium fluoride at 50 ° C. and 10% by weight phosphoric acid. It was post-treated with a mixture of monosodium, washed with water and dried.

[Photosensitive layer]
Next, the following photosensitive layer coating solution [P-1] was prepared and coated on the treated aluminum plate using a wire bar. Drying was carried out at 90 ° C. for 3 minutes with a hot air dryer to form a photosensitive layer. The coating amount after drying was 1.5 g / m ² .

<Photosensitive layer coating solution [P-1]>
・ Polymerizable compound (E-1) 0.6 g
・ Alkali-soluble resin (A-1) 2.0g
・ Infrared absorber (IR-1) 0.05g
-Polymerization initiator 1 (BO-1) 0.1g
-Polymerization initiator 2 (T-1) 0.1g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

 Polymerizable compound (E-1), specific alkali-soluble resin (A-1), infrared absorber (IR-1), polymerization initiator (OB-1) and polymerization initiator (used for the photosensitive layer coating solution) The structure of T-1) is shown below.

[Protective layer (overcoat layer)]
A mixed aqueous solution of polyvinyl alcohol (saponification degree: 98 mol%, polymerization degree: 500) and polyvinylpyrrolidone (BASF Corp., Rubiscor K-30) is applied to the surface of the photosensitive layer using a wire bar, and hot air drying is performed. It dried at 90 degreeC for 5 minutes with the apparatus. The content of PVA was 85% by mass, and the coating amount (coating amount after drying) was 2.45 g / m ² .
The photosensitive lithographic printing plate 1 was obtained as described above.

[Photosensitive lithographic printing plate 2]
[Photosensitive layer]
A photosensitive lithographic printing plate 2 was obtained in the same manner as the photosensitive lithographic printing plate 1 except that the following photosensitive layer coating solution [P-2] was prepared and the photosensitive layer coating solution [P-2] was used.

<Photosensitive layer coating solution [P-2]>
・ Polymerizable compound (E-1) 0.6 g
・ Alkali-soluble resin (A-2) 2.0g
・ Infrared absorber (IR-1) 0.05g
-Polymerization initiator 1 (BO-1) 0.1g
-Polymerization initiator 2 (T-1) 0.1g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

 The structure of the alkali-soluble resin (A-2) used for the photosensitive layer coating solution is shown below.

<Developer 1>
The following components were dissolved in water, and the developer was adjusted to pH = 11.0 with KOH.
-Specific anionic surfactant according to the present invention: (I-1) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 2>
The following components were dissolved in water, and the developer was adjusted to pH = 12.0 with KOH.
-Specific anionic surfactant according to the present invention: (I-2) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 3>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 11.5.
-Specific anionic surfactant according to the present invention: (I-3) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 4>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 11.5.
-Specific anionic surfactant according to the present invention: (I-1) 2.5% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 5>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 12.5.
-Specific anionic surfactant according to the present invention: (I-1) 9.5% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 6>
The following components were dissolved in water, and the developer was adjusted to pH = 11.0 with KOH.
-Specific anionic surfactant according to the present invention: (I-1) 2.5% by mass
-Anionic surfactant according to the present invention: (II-1) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Developer 7>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 11.5.
-Specific anionic surfactant according to the present invention: (I-1) 2.5% by mass
-Anionic surfactant according to the present invention: (II-1) 5.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparison developer 1>
The following components were dissolved in water, and the developer was adjusted to pH = 11.0 with KOH.
Anionic surfactant: Perex NB-L (Kao Corporation) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfinol 104E (manufactured by Air Products Japan Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparison developer 2>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 11.5.
-Specific anionic surfactant according to the present invention: (I-1) 0.5% by mass
Anionic surfactant: Perex NB-L (manufactured by Kao Corporation) 1.5% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparative developer 3>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 11.5.
-Specific anionic surfactant according to the present invention: (I-1) 0.6% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparison developer 4>
The following components were dissolved in water, and the developer was adjusted to pH = 11.0 with KOH.
-Specific anionic surfactant according to the present invention: (I-1) 1.0% by mass
Chelating agent: Kirest 4K-50 (made by Kirest Co., Ltd.) 2.5% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparative developer 5>
The following components were dissolved in water, and the developer was adjusted to pH = 11.0 with KOH.
-Specific anionic surfactant according to the present invention: (I-1) 1.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.05% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

<Comparison developer 6>
The following components were dissolved in water, and the developer was adjusted with KOH to pH = 12.5.
-Specific anionic surfactant according to the present invention: (I-1) 1 5.0% by mass
・ Chelating agent: Kirest 4K-50 (manufactured by Kirest Co., Ltd.) 0.25% by mass
-Antifoaming agent: Surfynol 104E (manufactured by Air Products Japan Co., Ltd.) 0.08% by mass
・ Potassium carbonate 0.2% by mass

The structures of the specific anionic surfactants (I-1), (I-2), (I-3), and (II-1) used in the developer are shown below.

[Evaluation: Printing plate 1]
The resulting photosensitive lithographic printing plate 1 is changed by 1.5 W in a range of resolution 2400 dpi, outer drum rotation speed 360 rpm, output 4 to 11 W with Kodak Polychrome Graphics Trendsetter 800IIQuantum equipped with a water-cooled 20 W infrared semiconductor laser. And exposed. After the exposure, the protective layer was removed by rinsing with tap water, and then developed with the developers of Examples and Comparative Examples at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics. As the finisher, a 1: 3 water dilution of GN-2K manufactured by Fuji Film Co., Ltd. was used.

(Developability evaluation)
Development was performed at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics, and the developability of the actual non-image area was observed. In the developability evaluation, ◯ represents no remaining film.

(FM screening test (image reproducibility))
The resulting photosensitive lithographic printing plate 1 was exposed with FM Staccato 36 at a resolution of 2,400 dpi, outer drum rotation speed 360 rpm, output 7 W with a Trendsetter 800 II Quantum manufactured by Kodak Polychrome Graphics equipped with a water-cooled 20 W infrared semiconductor laser. After the exposure, the protective layer was removed by rinsing with tap water, and then developed with the developers of Examples and Comparative Examples at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics. As the finisher, a 1: 3 water dilution of GN-2K manufactured by Fuji Film Co., Ltd. was used.
At this time, it was confirmed that the set value of 50.5 (± 0.5)% was reproduced in the FM mode using a halftone dot densitometer IC plate II (manufactured by Greytag Macbeth).

(Evaluation of printing durability)
The obtained lithographic printing plate 1 is 1 to 100% obtained at a resolution of 2,400 dpi, an outer drum rotation speed of 360 rpm, and an output of 7 W with a Trendsetter 800IIQuantum manufactured by Kodak Polychrome Graphics Inc. equipped with a water-cooled 20 W infrared semiconductor laser. A halftone dot image was printed on high-quality paper using a commercially available offset ink with a Ryobi printer. The printing was stopped each time 1,000 sheets were printed, and the image portion was enlarged by an electron micrograph, and the number of sheets was counted until a halftone dot image of 20 μm square was missing.

(Evaluation of development residue)
The above-mentioned coated photosensitive material 3,000 m ² was developed with the above-described developer using PK-1310II manufactured by Kodak Polychrome Graphics, and left for one week to examine the presence or absence of settling development debris. This result is also shown.
In the development residue evaluation, ◯ represents no precipitation. Δ represents a slight amount of precipitation, × represents a large amount of precipitation, and Δ × represents an intermediate amount of precipitation.

[Evaluation: Printing plate 2]
The obtained photosensitive lithographic printing plate 2 is 1.5 W in the range of resolution 2400 dpi, outer drum rotation speed 360 rpm, output 4 to 16.5 W, using Trendsetter 800 II Quantum manufactured by Kodak Polychrome Graphics equipped with a water-cooled 20 W infrared semiconductor laser. The exposure was carried out by changing each time. After the exposure, the protective layer was removed by rinsing with tap water, and then developed with the developers 6 and 7 and the developer of Comparative Example 6 at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics. As the finisher, a 1: 3 water dilution of GN-2K manufactured by Fuji Film Co., Ltd. was used.

(Developability evaluation)
Development was performed at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics, and the developability of the actual non-image area was observed. In the developability evaluation, ◯ represents no remaining film.

(FM screening test (image reproducibility))
The resulting photosensitive lithographic printing plate 2 was exposed to FM Staccato 36 at a resolution of 2,400 dpi, outer drum rotation speed 360 rpm, and output 16 W with a Trendsetter 800IIQuantum manufactured by Kodak Polychrome Graphics equipped with a water-cooled 20 W infrared semiconductor laser. After the exposure, the protective layer was removed by rinsing with tap water, and then developed with the developers of Examples and Comparative Examples at 30 ° C. for 15 seconds using PK-1310II manufactured by Kodak Polychrome Graphics. As the finisher, a 1: 3 water dilution of GN-2K manufactured by Fuji Film Co., Ltd. was used.
Under the present circumstances, FM mode was measured using halftone dot concentration meter IC plateII (made by a Gretag Macbeth company).

(Evaluation of printing durability)
The obtained lithographic printing plate 2 is 1 to 100% obtained at a resolution of 2,400 dpi, an outer drum rotation speed of 360 rpm, and an output of 16 W on a Trendsetter 800 II Quantum manufactured by Kodak Polychrome Graphics equipped with a water-cooled 20 W infrared semiconductor laser. A halftone dot image was printed on high-quality paper using a commercially available offset ink with a Ryobi printer. The printing was stopped each time 1,000 sheets were printed, and the image portion was enlarged by an electron micrograph, and the number of sheets was counted until a halftone dot image of 20 μm square was missing.

(Evaluation of development residue)
The above-mentioned coated photosensitive material 3,000 m ² was developed with the above-described developer using PK-1310II manufactured by Kodak Polychrome Graphics, and left for one week to examine the presence or absence of settling development debris. This result is also shown.
In the development residue evaluation, ◯ represents no precipitation. Δ represents a slight amount of precipitation, × represents a large amount of precipitation, and Δ × represents an intermediate amount of precipitation.

  As can be seen from Table 1, when the negative photosensitive lithographic printing plate is treated with the developer of the present invention, it is found that it is excellent in all of developability, FM screening image reproduction, printing durability, and development residue. It was. Furthermore, it was able to be improved into an excellent developer by combining specific anionic surfactants.

Claims (3)

A developer for a negative photosensitive lithographic printing plate comprising an anionic surfactant represented by the following formula (I) and a chelating agent, wherein the developer contains 1.0% by mass to 10% by mass of the anionic surfactant. A developing solution containing in the range of mass%, containing the chelating agent in the range of 0.05 mass% to 1.0 mass%, and having a pH of 11 to 12.5.

(In the formula, R ₁ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, m represents 1, 2 or 3, and M represents a monovalent group. Represents an alkali metal or NH _4. ) The developer according to claim 1, further comprising an anionic surfactant represented by the following formula (II).

(In the formula, R ₂ represents a linear or branched alkylene group having 1 to 5 carbon atoms, n represents an integer of 3 to 100, and M represents a monovalent alkali metal or NH _4. ) The developer according to claim 1 or 2, wherein the negative photosensitive lithographic printing plate targeted by the developer contains an alkali-soluble resin having a monomer unit represented by the following formula (III).

(In the above formulas, R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent. L ₁ and L ₂ are each independently Represents an alkyl group which may have a substituent or an aryl group which may have a substituent.)