JP2006178325A - Photopolymerizable composition and photosensitive lithographic printing plate using this photopolymerizable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photopolymerizable composition which can be photopolymerized by absorption of light in a wavelength range of 300-450 nm and excels in sensitivity and temporal stability, and a photosensitive lithographic printing plate excellent in sensitivity, printing durability and temporal stability. <P>SOLUTION: The photopolymerizable composition comprises an addition polymerizable compound having at least one ethylenically unsaturated double bond, a binder soluble or swellable in alkaline water, a sensitizing dye having a specific structure and a photoinitiator. The photosensitive lithographic printing plate uses the photopolymerizable composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photopolymerizable composition and a photosensitive lithographic printing plate. In particular, the present invention relates to a photosensitive lithographic printing plate having sensitivity in the wavelength range of 300 nm to 450 nm and excellent in sensitivity, printing durability, and storage stability.

  In general, a negative photosensitive lithographic printing plate (original) is obtained by coating a photosensitive composition on a roughened aluminum plate or the like, exposing a desired image, and exposing an image portion (light irradiated). Image formation is performed by a process of polymerizing or cross-linking the portion) to insolubilize it in a developer and eluting non-image areas with the developer. Conventionally, as a photosensitive composition used for such a purpose, a photopolymerizable composition is well known, and a part thereof is put into practical use. High-sensitivity photopolymers that incorporate recent photoinitiator technology that is sensitive to visible light have become more sensitive to the area used for direct plate making with visible lasers, and have become popular as so-called CTP (Computer To Plate) plates. ing.

  A typical photopolymerization printing plate has previously been exposed by an Ar ion laser (488 nm) or FD-YAG laser (532 nm), but was originally a low-cost blue or violet laser developed for storing data on a DVD. The availability of diodes has become extremely easy, making it possible to produce plate setters that operate at shorter wavelengths. More specifically, semiconductor lasers emitting at 350 to 450 nm are realized using InGaN materials, and plate setters using these can be handled under a yellow light and can be made inexpensive, and there are signs of widespread use.

Photopolymerizable printing plates that are sensitized for a wavelength range of 350 to 450 nm are also described in the prior art. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-147663) discloses a combination of a merocyanine dye having a specific structure and a titanocene initiator, Patent Document 2 (Japanese Patent Laid-Open No. 2003-221517), a dye having an oxazolidinone skeleton and a titanocene initiator, A photopolymerizable composition using a combination initiating system of a fluorescent whitening agent and various initiators described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2003-29426) has been described. For plate making with a laser diode, sufficient sensitivity is not obtained, or storage stability is low, and improvement has been demanded.
JP 2000-147663 A JP 2003-221517 A JP 2003-29426 A

  An object of the present invention is to provide a highly sensitive photopolymerizable composition that can be photopolymerized by absorbing light in the wavelength range of 300 to 450 nm and that can be exposed by a low-cost laser with a small output. is there. It is another object of the present invention to provide a photopolymerizable composition having high storage stability in which a residual film or the like due to dark polymerization does not occur in a high temperature and high humidity environment or over a long period of time. Furthermore, the present invention provides a photosensitive lithographic printing plate having excellent printing durability and excellent sensitivity and storage stability.

As a result of intensive studies on a combined initiation system of various sensitizing dyes and an initiating system in order to solve the above problems, the present inventors have found that a sensitizing dye represented by the general formula (I) and a specific photoinitiator By using the combined use initiation system, it was found that a photopolymerizable composition having high sensitivity and high storage stability with respect to light in a wavelength region of 300 to 450 nm was obtained, and the present invention was achieved.
That is, the present invention is as follows.

(1) Contains an addition-polymerizable compound having at least one ethylenically unsaturated double bond, an alkaline water-soluble or swellable binder, a sensitizing dye represented by the following general formula (I), and a photoinitiator A photopolymerizable composition characterized by comprising:

In general formula (I), X represents a nonmetallic atom or a nonmetallic atomic group, and n is 0-5. When n is 2 to 5, a plurality of Xs may be different. Moreover, several X may couple | bond together and it may form the ring. Y represents —O—, —S—, or> N—R ¹ . R ¹ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent. R represents an aromatic ring or a hetero ring which may have a substituent.

(2) The photoinitiator is an aromatic ketone, aromatic onium salt, thio compound, hexaarylbiimidazole compound, ketoxime ester compound, organic peroxide, borate compound, azinium compound, metallocene compound, active ester compound, and The photopolymerizable composition as described in (1) above, which is at least one compound selected from compounds having a carbon-halogen bond.
(3) A photosensitive lithographic printing plate provided with an image recording layer containing the photopolymerizable composition according to (1) or (2) above on a support.

  According to the present invention, a photopolymerizable composition having high sensitivity and excellent storage stability is provided, and further, using this, the photosensitivity excellent in high printing durability as well as high sensitivity and storage stability. A lithographic printing plate is provided. The photopolymerizable composition of the present invention can also be applied to a photoresist for preparing a printed circuit board, three-dimensional modeling, a hologram material, and the like.

  The present invention will be described in detail below.

<Photopolymerizable composition>
The photopolymerizable composition of the present invention comprises an addition-polymerizable compound having at least one ethylenically unsaturated double bond (hereinafter sometimes abbreviated as “ethylenically unsaturated bond-containing compound”), alkaline water or A soluble or swellable binder and a photopolymerization initiator are essential components, and various compounds such as a colorant, a plasticizer and a thermal polymerization inhibitor can be used in combination as necessary.

(Addition polymerizable compound having at least one ethylenically unsaturated double bond)
Here, an addition-polymerizable compound having at least one ethylenically unsaturated double bond (hereinafter, also referred to as an ethylenically unsaturated bond-containing compound) is when the photopolymerizable composition is irradiated with actinic rays. A compound having an ethylenically unsaturated double bond that undergoes addition polymerization, crosslinking and curing by the action of a photopolymerization initiator. The compound containing an ethylenically unsaturated double bond can be arbitrarily selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. For example, it has 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 esters of unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and aliphatic polyhydric alcohol compounds, unsaturated Examples include amides of carboxylic acids and aliphatic polyvalent amine compounds.
Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pen Erythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer Etc.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p − (3− Methacryloxy-2-hydroxypropoxy) phenyl] dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like.

Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,5-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.
Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate. Furthermore, the mixture of the above-mentioned ester monomer can also be mentioned.
Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.

  As another example, a polyisocyanate compound having two or more isocyanate groups in one molecule described in JP-B-48-41708 contains a hydroxyl group represented by the following general formula (A). Examples thereof include a vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule to which a vinyl monomer is added.

_{CH 2 = C (R) COOCH} 2 CH (R ') OH (A)
(However, R and R ′ each independently represents a hydrogen atom or a methyl group.)

Further, urethane acrylates as described in JP-A-51-37193 and JP-B-2-32293, JP-A-48-64183, JP-B-49-43191, JP-B-52-30490 Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid, as described in each publication. Furthermore, those introduced as photocurable monomers and oligomers in Journal of Japan Adhesion Association, Vo 1.20, No. 7, pages 300 to 308 (1984) can also be used.
The addition amount of the ethylenically unsaturated bond-containing compound is generally 10 to 80% by mass, preferably 30 to 70% by mass, based on the entire photopolymerizable composition.

(Alkaline water soluble or swellable binder)
The alkaline water-soluble or swellable binder (hereinafter, also simply referred to as polymer binder) used in the photopolymerizable composition of the present invention not only functions as a film forming agent but also needs to be dissolved in an alkaline developer. Therefore, an organic high molecular polymer that is soluble or swellable in alkaline water is used. For example, when the water-soluble organic polymer is used as the organic polymer, water development is possible. Examples of such an organic polymer include addition polymers having a carboxylic acid group in the side chain, such as JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54- No. 25957, JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, that is, methacrylic acid copolymer, acrylic acid copolymer, Examples thereof include an itaconic acid copolymer, a crotonic acid copolymer, a maleic acid copolymer, and a partially esterified maleic acid copolymer.

  Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful. Among these, [benzyl (meth) acrylate / (meth) acrylic acid / other addition-polymerizable vinyl monomers as required] copolymers and [allyl (meth) acrylate (meth) acrylic acid / as required Other addition polymerizable vinyl monomers] copolymers are preferred. In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble organic polymer. In order to increase the strength of the cured film, alcohol-soluble polyamide, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful. JP-B-7-120040, JP-B7-120041, JP-B7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A1-271741 And polyurethane resins described in JP-A-11-352691 are also useful for the use of the present invention.

These organic polymer polymers can improve the strength of the cured film by introducing a radical reactive group into the side chain. Functional groups that can undergo an addition polymerization reaction include ethylenically unsaturated bond groups, amino groups, and epoxy groups, and functional groups that can become radicals upon light irradiation include mercapto groups, thiol groups, halogen atoms, triazine structures, and onium salt structures. In addition, examples of the polar group include a carboxyl group and an imide group. The functional group capable of undergoing addition polymerization reaction is particularly preferably an ethylenically unsaturated bond group such as an acryl group, a methacryl group, an allyl group, or a styryl group, but an amino group, a hydroxy group, a phosphonic acid group, a phosphoric acid group, a carbamoyl group, Functional groups selected from isocyanate groups, ureido groups, ureylene groups, sulfonic acid groups, and ammonio groups are also useful.

In order to maintain the developability of the photosensitive layer, the polymer binder preferably has an appropriate molecular weight and acid value, and a polymer having a mass average molecular weight of 5,000 to 300,000 and an acid value of 20 to 200 meq / g is effective. Used for.
These polymer binders can be mixed in an arbitrary amount in the composition. In the composition, particularly 90% by mass or less gives preferable results in terms of formed image strength and the like, preferably 10 to 90% by mass, more preferably 30 to 80% by mass.
The photopolymerizable ethylenically unsaturated bond-containing compound and the polymer binder are preferably in the range of 1/9 to 9/1 by mass ratio. A more preferable range is 2/8 to 8/2, still more preferably 3/7 to 7/3.

(Light initiation system)
The photoinitiating system of the present invention comprises at least a sensitizing dye represented by the following general formula (I), a photoinitiator, and, if necessary, a co-sensitizer such as a chain transfer agent.

In general formula (I), X represents a nonmetallic atom or a nonmetallic atomic group, and n is 0-5. When n is 2 to 5, a plurality of Xs may be different. Moreover, several X may couple | bond together and it may form the ring. Y represents —O—, —S—, or> N—R ¹ . R ¹ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent. R represents an aromatic ring or a hetero ring which may have a substituent.

The nonmetallic atom or nonmetallic atomic group as X preferably has 20 or less carbon atoms, and specifically includes, for example, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, etc.), a heterocyclic group, and a carboxy group. , A halogen atom, an alkoxy group, —N (R ² ) (R ³ ) (R ² and R ³ independently represent an alkyl group or an aryl group), and the like.
Examples of the ring formed by combining two Xs include an aromatic ring and a hetero ring.
n is preferably 0-2.

Y represents —O—, —S—, or> N—R ¹ .
Examples of the alkyl group having 1 to 8 carbon atoms as R ¹ include a methyl group, an ethyl group, a propyl group, and a butyl group.
Examples of the aromatic ring or hetero ring which may have a substituent for R include a benzene ring, a naphthalene ring, a hetero ring, and a condensed ring thereof.

The substituent which the alkyl group having 1 to 8 carbon atoms as R ^{1 and} the aromatic ring or heterocyclic ring as R may have is preferably 20 or less carbon atoms, for example, a halogen atom, a cyano group, An alkoxy group, an alkoxycarbonyl group, etc. can be mentioned.
As for the aromatic ring or hetero ring as R, an alkyl group can be further exemplified as a substituent.

  The sensitizing dye represented by the above general formula (I) has an absorption maximum in the range of 300 nm to 450 nm and has a high molecular extinction coefficient. Therefore, the photosensitizing state is efficiently increased due to the interaction with the photoinitiator. Indicates radical generation efficiency. Specific compounds (I) -1 to (I) -15 are shown below, but are not limited thereto.

  The sensitizing dye represented by the general formula (I) can be synthesized by various methods. For example, the benzoylglycine which may have a substituent and the aromatic which may have a substituent The aldehyde can be synthesized by condensing acetic anhydride with sodium acetate catalyst.

  The method of using these sensitizing dyes can be arbitrarily set according to the performance design of the light-sensitive material, like the above-described addition polymerizable compound. For example, the compatibility with the photosensitive layer can be enhanced by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film properties of the photosensitive layer. The photosensitivity and resolution of the photosensitive layer and the physical properties of the exposed film have a great influence on the absorbance at the light source wavelength. Therefore, the addition amount of the sensitizing dye is appropriately selected in consideration of these factors. For example, the sensitivity decreases in a low region where the absorbance is 0.1 or less. Also, the resolution becomes low due to the influence of halation. However, for the purpose of curing a thick film of, for example, 5 μm or more, there are cases where such a low absorbance can be increased instead. In the region where the absorbance is as high as 3 or more, most of the light is absorbed on the surface of the photosensitive layer, and the internal curing is further inhibited. For example, when used as a printing plate, the film strength and the substrate adhesion are poor. It will be insufficient.

  When used as a photosensitive lithographic printing plate used in a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance of the photosensitive layer is in the range of 0.1 to 3.0, particularly 0.25 to 1. It is preferable to set so as to be in the range of 5. When used as a photosensitive lithographic printing plate, this is usually 0.05 to 30 parts by weight, preferably 0.1 to 20 parts by weight, more preferably 0.2 to 0.2 parts by weight with respect to 100 parts by weight of the photosensitive layer component. The range is 10 parts by mass.

As the photoinitiator, known photopolymerization initiators can be used, and suitable types include aromatic ketones, aromatic onium salts, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, Examples include organic peroxides, borate compounds, azinium compounds, metallocene compounds, active ester compounds, and compounds having a carbon-halogen bond. Many specific examples of such a photoinitiating system are described in EP-A 1091247 and JP-A-8-262714.
Among them, hexaarylbiimidazole and titanocene compounds give high sensitivity and good storage stability when used in combination with the sensitizing dye.

The method of using hexaarylbiimidazole in the photopolymerization composition is described in JP-B No. 45-37377, JP-A No. 54-155292, EP 107792, US Pat. No. 4,410,621. Preferred specific examples include, for example, 2 4,5,2 ′, 4 ′, 5′-hexaphenylbisimidazole, 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2 ′ -Bis (2-bromophenyl) -4,5,4 ', 5'-tetraphenylbisimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,5,4', 5'-tetraphenyl Bisimidazole, 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetrakis (3-methoxyphenyl) bisimidazole, 2,2′-bis (2-chlorophenyl) -4 , 5,4 ′, 5′-tetrakis (3,4,5-trimethoxyphenyl) -bisimidazole, 2,5,2 ′, 5′-tetrakis (2-chlorophenyl) -4,4′-bis (3 , 4-Dimethoxyphenyl) bisimidazole, 2,2′-bis (2,6-dichlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2-nitrophenyl) -4,5,4 ', 5'-tetraphenylbisimidazole, 2,2'-di-o-tolyl-4,5,4', 5'-tetraphenylbisimidazole, 2,2'-bis (2 -Ethoxyphenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole and 2,2′-bis (2,6-difluorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole Can be mentioned.

  Various titanocene compounds can be used. For example, various titanocene compounds described in JP-A-59-152396 and JP-A-61-151197 can be appropriately selected and used. . More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2 , 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4-di-fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti -Bis-2, - difluoro-1-yl, di - cyclopentadienyl -Ti- bis-2,6-difluoro-3- (pyrr-1-yl) - can be exemplified 1-yl and the like. Further, if necessary for the above photoinitiator, thiol compounds such as 2-mercaptobenzthiazole, 2-mercaptobenzimidazole and 2-mercaptobenzoxazole, and amines such as N-phenylglycine and N, N-dialkylamino aromatic alkyl esters It is known that the photoinitiating ability can be further enhanced by adding a hydrogen-donating compound such as a compound.

The addition amount of the photoinitiator is generally 0.01 to 30% by mass, preferably 0.5 to 20% by mass with respect to the ethylenically unsaturated bond-containing compound.
Furthermore, in the present invention, in order to obtain high sensitivity, it is possible to add an amine compound and a sulfur compound having chain transfer properties as necessary. Examples include thiols such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, and 2-mercaptobenzimidazole. These amounts are generally used in the range of 0.1 to 30% by mass, preferably 0.5 to 20% by mass with respect to the ethylenically unsaturated bond-containing compound.

  In addition to the above-mentioned essential components, the photopolymerizable composition of the present invention can be used in combination with various compounds such as a thermal polymerization inhibitor, a colorant, a surfactant, and a plasticizer as necessary.

  Hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4-thiobis (3-methyl-6-t-butylphenol), 2 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine primary cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the total composition. If necessary, a higher fatty acid derivative such as behenic acid or behenamide is added to prevent polymerization inhibition by oxygen, and it is unevenly distributed on the surface of the photopolymerizable photosensitive layer in the process of drying after coating. May be. The addition amount of the higher fatty acid derivative or the like is preferably about 0.5% by mass to about 10% by mass of the total composition.

  Further, a colorant may be added for the purpose of coloring the photopolymerizable photosensitive layer. Examples of the colorant include phthalocyanine pigments (CIPigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, azo dyes, There are anthraquinone dyes and cyanine dyes. The addition amount of the dye and the pigment is preferably about 0.5% by mass to about 20% by mass of the total composition. In addition, in order to improve the physical properties of the cured film, an additive such as an inorganic filler or a plasticizer such as dioctyl phthalate, dimethyl phthalate, or tricresyl phosphate may be added. These addition amounts are preferably 10% by mass or less of the total composition.

A surfactant can be added to the photopolymerizable composition of the present invention in order to improve the coating surface quality. The coating amount is generally in the range of about 0.1 g / m ² to about 10 g / m ² in terms of mass after drying. More preferably from 0.3 to 5 g / m ^2. More preferably from 0.5 to 3 g / m ^2.

<Description of usage pattern in photosensitive lithographic printing plate>
Next, the case where the photopolymerizable composition of the present invention is applied to a photosensitive lithographic printing plate will be described. Usually, in the photosensitive lithographic printing plate, a form in which a photosensitive layer (image recording layer) containing the photopolymerizable composition is provided on a support such as an aluminum plate and, if necessary, an intermediate layer or a protective layer. Used in.

  In order to provide the photopolymerizable composition on a support, a photosensitive layer coating solution is prepared by dissolving a predetermined amount of the essential components and other additives as required in a suitable organic solvent. What is necessary is just to apply | coat and dry on a support body. Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 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, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene 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-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are ethyl and the like. These solvents can be used alone or in combination. In addition, 1-50 mass% is suitable for the density | concentration of the solid content in a coating solution.

(Support)
In order to obtain a photosensitive lithographic printing plate which is one of the main objects of the present invention, it is desirable to provide the photosensitive layer on a support having a hydrophilic surface. As the hydrophilic support, a conventionally known hydrophilic support used for 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 (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.) Paper or plastic film, etc., laminated or vapor-deposited with such metals is included, and appropriate physical and chemical treatments are applied to these surfaces for the purpose of imparting hydrophilicity and improving strength as necessary. You may give it.

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

The aluminum substrate is a metal plate mainly composed of dimensionally stable aluminum. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or aluminum (alloy) is laminated or Selected from vapor-deposited plastic film or paper.

In the following description, the above-mentioned substrates made of aluminum or an aluminum alloy are generically used as an aluminum substrate. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and used materials such as JIS A 1050, JIS A 1100, JIS A 3103, and JIS A 3005 are appropriately used. It can be used. The thickness of the aluminum substrate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.2 mm to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's desire. The aluminum substrate may be subjected to a substrate surface treatment described later as necessary. Of course, it may not be applied.

(Roughening treatment)
The aluminum substrate is usually roughened. Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Electrochemical roughening method that further electrochemically roughens in hydrochloric acid or nitric acid electrolyte solution, and a wire brush grain method in which the aluminum surface is scratched with a metal wire, and a pole in which 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 the 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 roughened in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity at the time of anode is 50 C / dm ^{2 to} 400 C / d ² . It is a range. More 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, alternating at a current density of 100C / dm ² ~400C / dm ² It is preferable to perform 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 processing as described above, the method condition is not particularly limited as long as the center line average group Ra Ra of the processing surface is 0.2 to 0.5 μm.

[Anodizing treatment]
The aluminum substrate that has been roughened as described above is then anodized to form an oxide film. In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of an 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, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples 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 10,000 ppm. May be included. There are no particular limitations on the conditions for the anodizing treatment, but the treatment is preferably performed by direct current or alternating current electrolysis at a treatment liquid temperature of 10 to 70 ° C. and a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter. . The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. Preferably it is the range of 0.5-1.0 micrometer.

  Furthermore, after performing these treatments, water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having sulfonic acid groups in the side chain, polyacrylic acid, water-soluble metal salts (for example, zinc borate) or Those having a primer such as a yellow dye or an amine salt are also suitable. Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-7-159983 is covalently used.

  As another preferred example, a substrate provided with a water-resistant hydrophilic layer as a surface layer on an arbitrary support can be raised. Examples of such a surface layer include a layer composed of an inorganic pigment and a binder described in US Pat. No. 3,055,295 and JP-A-56-13168, and a hydrophilic swelling described in JP-A-9-80744. A layer, a sol-gel film made of titanium oxide, polyvinyl alcohol, silicic acid or the like described in JP-A-8-507727 can be raised. These hydrophilic treatments are performed to make the surface of the support hydrophilic, in order to prevent harmful reaction of the photopolymerizable composition provided thereon, and to improve the adhesion of the photosensitive layer. It is given for the purpose.

[Middle layer]
The photosensitive lithographic printing plate may be provided with an intermediate layer for the purpose of improving adhesion between the photosensitive layer and the substrate and soiling. Specific examples of such an intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, Special Kaihei 8-320551, JP 9-34104, JP 9-236911, JP 9-269593, JP 10-69092, JP 10-115931, JP 10-161317, JP 10-260536, JP-A-10-282682, JP-A-11-84684, JP-A-11-38635, JP-A-11-38629, JP 10-282645, JP 10-301262, JP 11-24277, JP 11-109641, JP 10-319600, JP 11-327152, JP 2000-10292, JP Examples described in JP 2000-235254 A, JP 2000-352824 A, JP 2001-209170 A, and the like.

[Protective layer]
When the photosensitive lithographic printing plate having the photopolymerizable composition of the present invention is subjected to scanning exposure, the exposure is usually carried out in the air, so that the protective layer is further protected on the photosensitive layer containing the photopolymerizable composition. It is preferable to provide a layer. 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, and enables exposure in the atmosphere. To do. Therefore, the properties desired for such a protective layer are low permeability of low-molecular compounds such as oxygen, and further, transmission of light used for exposure is not substantially inhibited, and adhesion to the photosensitive layer is excellent. And it is desirable that it can be easily removed in the development process after exposure. Such a device for the protective layer has been conventionally devised, which is described in detail in US Pat. No. 3,458,311 and JP-A-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 (PVA), polyvinyl pyrrolidone, acidic celluloses, gelatin, Arabic Water-soluble polymers such as rubber and polyacrylic acid are known, but among these, using polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. give. The polyvinyl alcohol 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 for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100% and a molecular weight in the range of 300 to 2400.

  Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, 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.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like 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 the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. 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.

  As these measures, 5-80% by mass of an additive such as an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer is mixed in a hydrophilic polymer mainly composed of polyvinyl alcohol, on the polymerization layer. It is known to laminate. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and JP-A-55-49729.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (such as a water-soluble dye) that is excellent in the transmission of light from 350 nm to 450 nm and that can absorb light of 500 nm or more, which is used for exposure, it is safe light without causing a decrease in sensitivity. The aptitude can be further enhanced.

  When a photosensitive material using the photopolymerizable composition of the present invention is used as an image forming material, usually, after image exposure, an unexposed portion of the photosensitive layer is removed with a developer to obtain an image.

In addition, as the plate making process using the photosensitive lithographic printing plate of the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, the image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to perform the entire post-heating or the entire exposure on the developed image. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as covering up to the non-image area occur. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

  As a method for exposing the photosensitive lithographic printing plate, a known method can be used without limitation. A desirable wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN-based semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. The photosensitive layer component of the present invention can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component. A lithographic printing plate having such a structure is used in a printing machine. After loading on top, exposure-development can be performed on the machine.

Further, as other exposure light rays for the photopolymerizable composition according to the present invention, ultrahigh pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet lasers. A lamp, a fluorescent lamp, a tungsten lamp, sunlight, etc. can also be used. As available laser light sources of 350 nm to 450 nm, the following can be used. As a gas laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser as Nd: YAG (YVO ₄ ) and SHG crystal × 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), KNbO ₃ ring resonator (430 nm, 30 mW) as a semiconductor laser system A combination of a waveguide type wavelength conversion element and AlGaAs, InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), a combination of a waveguide type wavelength conversion element, AlGaInP, and an AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 10 mW) 0 mW), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW) Others, N ₂ laser (337 nm as a pulse laser, pulse: 0.1 to 10), XeF (351 nm, pulse 10 to 250 mJ) particular AlGaInN semiconductor laser in this (commercially available InGaN-based semiconductor lasers 400 to 410 nm, 5 to 30 mW) are preferable in terms of wavelength characteristics and cost.

  As the exposure apparatus for the photosensitive lithographic printing plate of the scanning exposure system, there are an internal drum system, an external drum system, and a flat bed system as an exposure mechanism, and a light source that can continuously oscillate among the above light sources is preferably used. can do. Practically, the following exposure apparatus is particularly preferable in terms of the relationship between the photosensitive material sensitivity and the plate making time.

(1) Single-beam to triple-beam exposure equipment that uses one or more gas lasers or solid-state laser light sources so that the internal drum system produces a semiconductor laser with a total output of 20 mW or more. (2) Total output of 20 mW or more with a flat bed system. (1) Multi-beam (1 to 10) exposure apparatus using one or more semiconductor lasers, gas lasers or solid-state lasers (3) Semiconductor laser, gas so that the total output is 20 mW or more with the external drum system Multi-beam (1-9) exposure device using one or more lasers or solid lasers (4) Multi-beam using one or more semiconductor lasers or solid lasers so that the total output is 20 mW or more with the external drum system (10 or more) exposure devices In the above laser direct drawing type photosensitive lithographic printing plate In general, the sensitivity between the photosensitive material sensitivity X (J / cm ² ), the photosensitive material exposure area S (cm ² ), the power q (W) of one laser light source, the number of lasers n, and the total exposure time t (s). Equation (eq1) holds.
X · S = n · q · t-(eq 1)

i) In the case of the internal drum (single beam) system, the laser rotation speed f (radian / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dot / cm), and the total exposure time t (s) In general, equation (eq 2) holds.
f.Z.t = Lx-(eq 2)

ii) External drum (multi-beam) system Drum rotation speed F (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), number of beams In general, the equation (eq 3) is established during (n).
F.Z.n.t = Lx-(eq 3)

iii) In the case of the flat head (multi-beam) system, the rotational speed H (radian / s) of the polygon mirror, the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dot / cm), the total exposure time t (s), Equation (eq4) is generally established between the number of beams (n).
F.Z.n.t = Lx-(eq 4)

Resolution (2560 dpi) required for actual photosensitive lithographic printing plate, plate size (A1 / B1, sub-scanning length 42 inches), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the photosensitive composition of the present invention ( By substituting (sensitivity wavelength, sensitivity: about 0.1 mJ / cm ² ) into the above formula, it is understood that a combination with a multi-beam exposure method using a laser having a total output of 20 mW or more is preferable in the photosensitive material of the present invention. it can. However, when a laser having a necessary and sufficient output (30 mW or more) is used, a combination with an internal drum type semiconductor laser single beam exposure apparatus is most preferable in terms of operability and cost.

  In addition, a heating process is performed at a temperature of 50 ° C. to 150 ° C. for a period of 1 second to 5 minutes in order to increase the curing rate of the photopolymerization type photosensitive layer after image exposure with conventionally known actinic light and development. Thus, the curability of the non-image area can be improved and the printing durability can be further improved, which is more preferable.

  Further, the developed photosensitive lithographic printing plate is washed with water, a surfactant, etc. as described in JP-A Nos. 54-8002, 55-1115045, 59-58431, etc. And a desensitizing solution containing gum arabic, starch derivatives and the like. These treatments can be used in various combinations for the post-treatment of the photosensitive lithographic printing plate of the present invention. The lithographic printing plate obtained by such treatment is applied to an offset printing machine and used for printing a large number of sheets.

  The above-described photosensitive lithographic printing plate can be developed with a conventionally known developer to form an image. In particular, the following special developer is used in terms of image formability and development residue. To preferred. Examples of these conventionally known developers include developers described in JP-B-57-7427, such as sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, Such as inorganic alkaline agents such as tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia etc. and monoethanolamine or diethanolamine etc. An aqueous solution of an organic alkali agent is suitable. It is added so that the concentration of such an alkaline solution is 0.1 to 10% by mass, preferably 0.5 to 5% by mass.

Such an alkaline aqueous solution may contain a small amount of a surfactant, an organic solvent such as benzyl alcohol, 2-phenoxyethanol, and 2-butoxyethanol as necessary. Examples thereof include those described in US Pat. Nos. 3,375,171 and 3,615,480. Furthermore, the developing solution described in each gazette of Unexamined-Japanese-Patent No. 50-26601, 58-54341, Japanese Patent Publication No. 56-39464, and 56-42860 can also be mentioned.

(Developer)
The developer used in the plate making method of the photosensitive lithographic printing plate of the present invention preferably contains a nonionic surfactant having an inorganic alkali salt and a polyoxyalkylene ether group, and has a pH of 11.0 to 12.2. 7.

  The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

When silicate is used, developability can be achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ , which is a component of silicate, and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). Can be easily adjusted. Among the aqueous alkali solutions, the mixing ratio (SiO ₂ / M ₂ O: molar ratio) between the silicon oxide SiO ₂ and the alkali oxide M ₂ O is preferably 0.5 to 3.0, and preferably 1.0 to 2 0.0 is more preferable. Moreover, it is preferable that the content of a silicate is 1-10 mass% with respect to the mass of alkaline aqueous solution, 3-8 mass% is more preferable, and 4-7 mass% is the most preferable.

  In addition, an organic alkali agent may be supplementarily used for the purpose of finely adjusting the alkali concentration and assisting the solubility of the photosensitive layer. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

  The developer used in the present invention must contain a nonionic surfactant having a polyoxyalkylene ether group. By adding this surfactant, the dissolution of the photosensitive layer in the unexposed area is promoted, and the exposed area. It is possible to reduce the permeability of the developer into the liquid. As the surfactant containing a polyoxyalkylene ether group, one having a structure of the following general formula (II) is preferably used.

R ⁴ —O— (R ⁵ —O) _pH (II)
In the formula, R ⁴ has an optionally substituted alkyl group having 3 to 15 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, or a substituent. A heteroaromatic cyclic group having 4 to 15 carbon atoms (wherein the substituent is an alkyl group having 1 to 20 carbon atoms, a halogen atom such as Br, Cl or I, or an aromatic hydrocarbon having 6 to 15 carbon atoms) group, an aralkyl group having from 7 to 17 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, alkoxy of 2-20 carbon atoms -. the carbonyl group, and an acyl group having 2 to 15 carbon atoms) shows a, R ⁵ is , An optionally substituted alkylene group having 1 to 100 carbon atoms (in addition, examples of the substituent include an alkyl group having 1 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 15 carbon atoms). P represents an integer of 1 to 100.

In the definition of the above formula (II), specific examples of the “aromatic hydrocarbon group” include phenyl group, tolyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group and the like, and “heteroaromatic ring” Specific examples of the “group” include a furyl group, a thionyl group, an oxazolyl group,
Examples include an imidazolyl group, a pyranyl group, a pyridinyl group, an acridinyl group, a benzofuranyl group, a benzothionyl group, a benzopyranyl group, a benzoxazolyl group, and a benzoimidazolyl group.

In addition, the part of (R ⁵ —O) _p in the formula (II) may be two or three groups as long as it is in the above range. Specific examples include a combination of random or block combinations of ethyleneoxy and propyleneoxy, ethyleneoxy and isopropyloxy, ethyleneoxy and butyleneoxy, ethyleneoxy and isobutylene, and the like. . In the present invention, the surfactant having a polyoxyalkylene ether group is used alone or in a composite system, and it is effective to add 1 to 30% by mass, preferably 2 to 20% by mass in the developer. If the addition amount is small, the developability is deteriorated. On the other hand, if the amount is too large, the development damage becomes strong and the printing durability of the printing plate is lowered.

  Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the above formula (II) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether and polyoxyethylene stearyl ether. Polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether and polyoxyethylene naphthyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Kind.

  Furthermore, you may add the other surfactant described below. Other surfactants include polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate Nonionic surfactants such as sorbitan alkyl esters such as glycerol monostearate and monoglyceride alkyl esters such as glycerol monooleate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, sodium butylnaphthalene sulfonate, pentyl naphthalene sulfonic acid Alkyl naphthalene sulfonates such as sodium, sodium hexyl naphthalene sulfonate, sodium octyl naphthalene sulfonate , Alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, sulfosuccinate ester salts such as sodium dilauryl sulfosuccinate; alkyl betaines such as lauryl betaine and stearyl betaine Amphoteric surfactants such as amino acids can be used, and anionic surfactants such as alkylnaphthalene sulfonates are particularly preferred.

  These surfactants can be used alone or in combination. Further, the content of these surfactants in the developer is preferably in the range of 0.1 to 20% by mass in terms of active ingredients.

  The pH of the developer is generally 11.0 to 12.7, preferably 11.5 to 12.5. The conductivity of the developer is preferably 3 to 30 mS / cm. Particularly preferred conductivity is in the range of 5-20 mS / cm.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

[Example 1]
(Method for producing aluminum support)
An aluminum plate having a thickness of 0.3 mm was etched by being immersed in 10% by mass sodium hydroxide at 60 ° C. for 25 seconds, washed with running water, neutralized with 20% by mass nitric acid, and then washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using a sinusoidal alternating waveform current at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / current density. At dm ² , the anodization treatment was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² . When the surface roughness was measured, it was 0.3 μm (Ra display according to JIS B0601).

[Coating intermediate layer]
Next, an intermediate layer coating solution having the following composition was applied to the aluminum support with a wire bar, and dried at 90 ° C. for 30 seconds using a warm air dryer. The coating amount after drying was 10 mg / m ² .

(Interlayer coating solution)
Ethyl methacrylate and 2-acrylamido-2-methyl-1-
Propanesulfonic acid sodium salt copolymer with a molar ratio of 75:25 (molecular weight 18,000) 0.1 g
2-Aminoethylphosphonic acid 0.1g
50g of methanol
Ion exchange water 50g

[Coating photosensitive layer]
On the intermediate layer, a photosensitive layer coating solution having the following composition was prepared, coated with a wheeler so that the film thickness after drying was 0.15 g / m ^2, and dried at 100 ° C. for 1 minute.

(Photosensitive layer coating solution)
Ethylenically unsaturated bond-containing compound: pentaerythritol tetramethacrylate
1.5g
Binder: 1.8g of the following structure

Sensitizing dye: Compound (I) -2 0.1 g
Photoinitiator: 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole 0.4 g
Sensitization aid: Mercaptobenzothiazole 0.2g
Colored pigment dispersion: 2.0 g of composition shown below
Thermal polymerization inhibitor: N-nitrosophenylhydroxylamine aluminum salt
0.01g
Surfactant: Dai Nippon Ink Chemical Co., Ltd. MegaFuck F176
0.02g
Methyl ethyl ketone 20.0g
Propylene glycol monomethyl ether 20.0g

(Composition of pigment dispersion)
Pigment Blue 15: 6 15 parts by mass Allyl methacrylate / methacrylic acid copolymer 10 parts by mass (copolymerization molar ratio 83/17) Thermal polymerization Cyclohexanone 15 parts by mass Methoxypropyl acetate 20 parts by mass Propylene glycol monomethyl ether 40 parts by mass

[Coating of protective layer]
A coating solution for a protective layer having the following composition was applied onto the photosensitive layer so that the dry coating mass was 2 g / m ² and dried at 100 ° C. for 2 minutes.
(Coating solution composition for protective layer)
4 g of polyvinyl alcohol (degree of saponification 98 mol%, degree of polymerization 550)
Polyvinylpyrrolidone (molecular weight 100,000) 1g
95g of water

The photosensitive lithographic printing plate obtained above was made by the following method and evaluated for sensitivity and printing durability.
(exposure)
Example 1 is an internal drum type experimental machine equipped with a 30 mW violet laser (532 nm), the light amount is adjusted so that the light amount on the plate surface is 0.1 mJ / cm ^2, and a gray scale is pasted on the plate surface, It was exposed from above. The gray scale is made so that the amount of light changes by 1 / √2, and the higher the number of gray scale steps, the higher the sensitivity.
(Development / plate making)
Fuji Photo Film Co., Ltd. automatic processor LP-850P2 (preheat temperature is 100 ° C.) was charged with the following developer and Fuji Photo Film Co., Ltd. finisher FP-2W, each with a developer temperature of 30 ° C. and a development time of 18 seconds. The plate exposed under the conditions was developed / plate making to obtain a lithographic printing plate.

(PH 11.6 aqueous solution having the following composition)
Sodium hydroxide 0.15 parts by mass The following structural compound 5.0 parts by mass Ethylenediaminetetraacetic acid / 4Na salt 0.1 parts by mass Water 94.75 parts by mass

As a result of initial sensitivity measurement under the above conditions, a value of 8 steps was obtained as the number of gray scale steps.
The printing durability was determined by examining the number of printed sheets in which a solid image produced under the above conditions was worn away in the printing process and no ink was applied. The printer used was a R201 type printer manufactured by Man Roland, and the ink used was GEOS G black (N) manufactured by Dainippon Ink.
This plate material could be printed up to 250,000 sheets without any problem of inking.
Next, as an evaluation of stability over time, the plate was left to stand in an atmosphere of 60 ° C. and 50% RH for 3 days, taken out, and evaluated for sensitivity (sensitivity after being left under high temperature and high humidity) by the same method as described above. There was no generation of residual film, and the gray scale value was 7.5 steps, and it became clear that the sensitivity fluctuation was small between the initial sensitivity and 0.5 steps.

[Examples 2 to 10, Comparative Examples 1 to 3]
The sensitizing dye, photoinitiator, and sensitization aid of Example 1 were changed as shown in Table 1, and other operations were carried out in exactly the same manner as in Example 1 to evaluate sensitivity, printing durability, and stability over time. Carried out. The results are shown in Table 1.

  As can be seen from Table 1, the Examples of the present invention are superior in sensitivity, printing durability, and stability over time as compared with Comparative Examples.

[Examples 11 to 18, Comparative Examples 4 to 6]
(Method for producing aluminum support)
An aluminum plate of material 1S having a thickness of 0.30 mm was used with a No. 8 nylon brush and an 800 mesh Bamiston water suspension, and the surface was grained and washed thoroughly with water. Etching was performed by immersing in 10% sodium hydroxide at 70 ° C. for 60 seconds, washing with running water, neutralizing and washing with 20% HNO ₃ , and washing with water. This was subjected to an electrolytic surface roughening treatment in a 1% nitric acid aqueous solution with a anodic electricity quantity of 300 coulomb / dm ² using a sinusoidal alternating current under the condition of V _A = 12.7V. When the surface roughness was measured, it was 0.45 μm (Ra indication). Subsequently, after dipping in 30% H ₂ SO ₄ aqueous solution and desmutting at 55 ° C. for 2 minutes, a cathode was placed on the grained surface in 33 ° C. and 20% H ₂ SO ₄ aqueous solution to obtain a current density. When anodized at 5 A / dm ² for 50 seconds, the thickness was 2.7 g / m ² .

[Coating intermediate layer]
Next, an intermediate layer coating solution having the following composition was applied to the aluminum support with a wire bar, and dried at 90 ° C. for 30 seconds using a warm air dryer. The coating amount after drying was 10 mg / m ² .
(Interlayer coating solution)
90g of methanol
10g of pure water
0.01g of the following structural compound

[Coating photosensitive layer]
On the intermediate layer, a photosensitive solution having the following composition was prepared, applied with a wheeler so that the film thickness after drying was 0.15 g / m ^2, and dried at 120 ° C. for 2 minutes.
(Photosensitive layer coating solution (photopolymerizable composition): details are given in Table 2)
Ethylenically unsaturated bond-containing compound (following structure) 2.0 g

  Binder: Urethane resin (the following structure) 1.5g

Sensitizing dye: compounds shown in Table 2 (addition amount is the same as the sensitizing dye of Example 1)
Photoinitiator: Compounds shown in Table 2 (addition amount is the same as the photoinitiator of Example 1)
Sensitization aid: compounds shown in Table 2 (addition amount is the same as that of Example 1)
Colored pigment dispersion: 2.0 g of the above composition
Thermal polymerization inhibitor: p-methoxyphenol 0.01 g
Surfactant: Megafac F176 0.02g
Methyl ethyl ketone 20.0g
Propylene glycol monomethyl ether 20.0g

[Coating of protective layer]
A protective layer coating solution having the following composition was coated on the photosensitive layer so that the dry coating mass was 2.5 g / m ² and dried at 100 ° C. for 2 minutes.
(Coating solution composition for protective layer)
4 g of polyvinyl alcohol (degree of saponification 95 mol%, degree of polymerization 800)
Polyvinylpyrrolidone (molecular weight 50,000) 0.5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 0.5g
95g of water

The photosensitive lithographic printing plate obtained above was made by the same method as in Example 1 and evaluated for sensitivity, printing durability, and stability over time.
The results are shown in Table 2.

  From Table 2, it became clear that the present invention has higher sensitivity and higher printing durability and better stability over time than the comparative example.

Claims (3)

An addition-polymerizable compound having at least one ethylenically unsaturated double bond, an alkaline water-soluble or swellable binder, a sensitizing dye represented by the following general formula (I), and a photoinitiator. A photopolymerizable composition characterized.
In general formula (I), X represents a nonmetallic atom or a nonmetallic atomic group, and n is 0-5. When n is 2 to 5, a plurality of Xs may be different. Moreover, several X may couple | bond together and it may form the ring. Y represents —O—, —S—, or> N—R ¹ . R ¹ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent. R represents an aromatic ring or a hetero ring which may have a substituent.   The photoinitiator is an aromatic ketone, aromatic onium salt, thio compound, hexaarylbiimidazole compound, ketoxime ester compound, organic peroxide, borate compound, azinium compound, metallocene compound, active ester compound, and carbon-halogen. The photopolymerizable composition according to claim 1, wherein the photopolymerizable composition is at least one compound selected from compounds having a bond.   A photosensitive lithographic printing plate provided with an image recording layer containing the photopolymerizable composition according to claim 1 or 2 on a support.