JP2002278083A - Developing solution and developing method for negative type photosensitive planographic printing plate for infrared laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer and a developing method for giving a printing plate excellent in image quality, not causing surface stain in printing and excellent in printing resistance without heating a plate material before development when a negative type photosensitive planographic printing plate sensitive to infrared laser light is developed. SOLUTION: The developing solution for a negative type photosensitive planographic printing plate for an infrared laser containing a surfactant, an alkali metal silicate and an alkali metal hydroxide and having 1-4 wt.% concentration of SiO2 in the alkali metal silicate, 2-5 wt.% concentration of the alkali metal hydroxide and an SiO2 to M2 O (M is the alkali metal) molar ratio of 0.5-1.1 is used as an alkaline developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for developing a negative photosensitive lithographic printing plate image-exposed by an infrared laser, and to a printing plate having good image quality and excellent printing durability. And a developing method.

[0002]

2. Description of the Related Art In recent years, computer-to-plate (CTP) technology has been developed in which digital data created on a computer is output directly to a printing plate without being output to film, and various lasers are used as output machines. Various types of mounted plate setters and photosensitive lithographic printing plates compatible with them have been actively developed. In the early stages of development, plate-setters equipped with relatively low-power lasers were mainly used, so photosensitive lithographic printing plates inevitably require higher sensitivity in order to make such low-output lasers more photosensitive. I was asked. After that, an infrared laser came to be mounted on the platesetter as a high-power laser,
It has become possible to increase the amount of light applied on a photosensitive lithographic printing plate to several orders of magnitude. For this reason, light energy has been converted to heat, and image formation in the heat mode has been used for producing printing plates. For example, JP-A-7-20
Nos. 629 and 7-271029 use a photothermal conversion dye that absorbs infrared light and converts it into heat, and thermally decomposes a latent acid generator to generate an acid in an infrared laser-irradiated part, which is a binder. A negative type lithographic printing plate which cures a mixture of a novolak resin and a resol resin by utilizing an acid-catalyzed crosslinking reaction is disclosed. In these cases, it was necessary to heat-treat the entire lithographic printing plate to 90 ° C. or higher after infrared laser irradiation in order to advance the acid-catalyzed crosslinking reaction. In the above-mentioned patent specification, an aqueous solution of a silicate such as 6% sodium metasilicate is recommended as a developing solution for the development after the heat treatment. In these cases, it is essential that the plate material be subjected to heat treatment prior to development, and after heat treatment, image formation is possible only by developing using a developer as described above, and it is difficult to withstand printing. To give a good image intensity. However, in the heat treatment of the plate material, the heating temperature tends to be uneven, and it is difficult to control the heating temperature and time uniformly over the entire surface of the plate material. For example, in a portion where the heating temperature is high, the solubility in the developer is remarkable. When the heating is insufficient, there are problems such as poor printing durability and image defects.

As another example of a negative type lithographic printing plate utilizing an infrared laser, JP-A-7-306528 and JP-A-7-306528.
JP-A-30-30280 and JP-A-10-312056 disclose examples in which development processing can be performed without performing the above-described heat treatment after exposure. However, even if development is performed with a developer containing triethanolamine, benzyl alcohol, or the like as the alkaline developer disclosed in the specification, sufficient image intensity cannot be obtained, and the printing durability of the printing plate is reduced. It was still insufficient.

[0004] When developing various negative-type photosensitive lithographic printing plates as described above, it is important to firstly omit the heat treatment before development. It is important to avoid such problems of image intensity non-uniformity and residual film residue, but there is a system that can be used as a developer for forming images with excellent printing durability without heat treatment. Secondly, in the case of a negative type, the image portion is generally formed of a crosslinked film, and when the unexposed portion is dissolved and removed with a developing solution, the swelling of the image portion with an alkali developing solution is suppressed. At present, there is a long-felt need for a developing solution for realizing good printability by preventing the residual film remaining in the non-image area.

In order to provide infrared light with sensitivity, it is necessary to add a dye having absorption to infrared light, but in general, dyes having absorption at long wavelengths have a long conjugated system. Due to the structure, the molecular weight becomes relatively larger than that of the visible light absorbing dye, resulting in a structure having increased hydrophobicity. Therefore,
When development is to be carried out using an alkaline aqueous developer intended for the present invention, for example, JP-A-54-62
Or use a developer containing sodium silicate / sodium hydroxide as described in 004 JP _{(SiO 2 / M 2 O =} 1.0~1.5), described in JP-B-57-7427 When a developer containing an alkali metal silicate / potassium hydroxide (SiO ₂ / M ₂ O = 1.0 to 1.5) is used within the range of the composition to be used, the penetration of such a developer causes Often hindered by hydrophobic dyes, the development proceeded slowly, and the negative photosensitive lithographic printing plate showed significant residual film remaining in non-image areas and poor elution. Furthermore, when the development processing of a large number of printing plates is performed, agglomerates are generated because the above-mentioned hydrophobic dye is insoluble in the developing solution, which causes inconvenience such as contamination of the developing unit roll. In many cases it was a problem.

In addition, when an attempt is made to develop a negative-type photosensitive lithographic printing plate without performing a heat treatment before development, for example, an SiO ₂ / M as described in JP-A-6-282079 is used. ₂ O = 0.5-2.0,
Even when a similar developer containing a compound obtained by adding ethylene oxide to a sugar alcohol is used, in the system using the infrared laser according to the present invention, the curability of the infrared laser irradiation part, which is the image part, is not sufficient. Is still not sufficient in many cases, and when development is performed using the above-described developer, the permeation into the image area is remarkable, causing damage to the image area or partial image omission. Problems may occur, or the solubility of the non-image portion, which is an unexposed portion, may be low, resulting in poor elution. Good elution of the non-image portion and the persistence of the image portion, that is, a laser beam irradiation portion At present, there is a long-awaited demand for a developer having a sufficiently increased contrast of solubility in an unirradiated portion.

[0007]

SUMMARY OF THE INVENTION The present invention provides an excellent image quality in developing a negative photosensitive lithographic printing plate having sensitivity to an infrared laser without subjecting the plate material to heat treatment before development. It is another object of the present invention to provide a developer and a developing method for providing a printing plate which is free from background stains during printing and has excellent printing durability.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing method using an alkaline developing solution without heat treatment after exposure, wherein the alkaline developing solution contains a surfactant, an alkali metal silicate and Containing alkali metal hydroxide,
And the concentration of SiO ₂ in the alkali metal silicate is 1 to 4
% By weight, the concentration of the alkali metal hydroxide is in the range of 2 to 5% by weight, and the molar ratio of SiO ₂ / M ₂ O (M represents an alkali metal) is in the range of 0.5 to 1.1, respectively. The problem is solved by using a developer for a negative photosensitive lithographic printing plate for infrared laser, which is characterized by being included.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a negative photosensitive lithographic printing plate utilizing an infrared laser is preferably not based on the above-mentioned heat-sensitive (heat mode) recording utilizing a light-to-heat conversion dye, but is based on infrared rays. A system that is photosensitive and induces a cross-linking reaction by chemically generating active species is preferable,
For example, a system using a combination of a photopolymerization initiator and a dye for spectrally sensitizing the photopolymerization initiator with infrared light is preferable.
Specific examples of these will be described later.

In the present invention, a surfactant, an alkali metal silicate and an alkali metal water are used as a developer when the above-mentioned negative photosensitive lithographic printing plate is developed without being subjected to a heat treatment before development. Containing an oxide, the concentration of SiO ₂ in the alkali metal silicate ranges from 1 to 4% by weight, the concentration of the alkali metal hydroxide ranges from 2 to 5% by weight, and S
It is the gist of the present invention that it is essential that the molar ratio of iO ₂ / M ₂ O (M represents an alkali metal) be included in the range of 0.5 to 1.1. The alkali metal silicate is one or a combination of two or more selected from sodium silicate, potassium silicate and lithium silicate, and the alkali metal hydroxide is sodium hydroxide, potassium hydroxide and lithium hydroxide. Refers to one or a combination of two or more selected from Each of these contains 1 to 4% by weight of an alkali metal silicate and 2 to 5% by weight of an alkali metal hydroxide in a developer, and SiO ₂ / M ₂ O (M represents an alkali metal). )
It is essential that the molar ratio is included in the range of 0.5 to 1.1. In the other range, a residual film remains and causes soiling, or an image is missing, It is not preferable because the printing durability during printing is inferior. Particularly when both potassium ions are contained in the alkali metal silicate and the alkali metal hydroxide in the alkali metal ions in an amount of at least 50 mol% with respect to the total alkali metal ions, the developability is remarkably improved. Therefore, the most preferable case is a case where all the alkali metal ions are potassium ions.

In the above case, when the molar ratio of SiO ₂ / M ₂ O is less than 0.5, the erosion of the image portion by the developer becomes remarkable, and inconveniences such as generation of image defects are caused. The effect of hydrophilizing the surface of the support with the silicate becomes insufficient, causing soiling during printing,
Alternatively, when an aluminum support is used, the aluminum surface may be corroded by alkali, which is not preferable. On the other hand, when the molar ratio of SiO ₂ / M ₂ O is more than 1.1, the developing property decreases because the permeability of the developing solution to the photosensitive layer of the negative-type infrared-sensitive lithographic printing plate is low. This is not preferable because poor elution of the image area occurs.
Further, the concentration of the alkali metal hydroxide contained in the developing solution is also important. In the above-mentioned preferred range of SiO ₂ / M ₂ O, the content is preferably 2 to 5% by weight. This is not preferred because the image quality deteriorates and elution failure occurs in the non-image area. If the concentration exceeds 5% by weight, the strength of the image area is reduced, and the printing durability during printing may be poor. In addition, the concentration of the alkali metal silicate in the developer is preferably in the range of 1 to 4% by weight, and if the concentration is less than 1% by weight, the effect of hydrophilizing the support is insufficient, and If the concentration exceeds 4% by weight, the developability may decrease, which is not preferable.

The addition of a surfactant in the present invention is essential for improving the wettability of the developing solution on the surface of the photosensitive layer and promoting the penetration of the developing solution into the photosensitive layer. It preferably contains a nonionic, nonionic or amphoteric surfactant, and its content is preferably in the range of 0.01 to 5% by weight in the developer, and more preferably 0.1 to 5% by weight.
It is particularly preferred that the content is in the range of from 0.5 to 2% by weight.
In particular, when it is used in the range of 0.1 to 2% by weight, the generation of sludge in the developer can be effectively prevented even during the development processing of a large number of sheets, which is particularly preferable.

Examples of the cationic surfactant include, for example,
Quaternary ammonium salts such as lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, perfluorotrimethylammonium chloride, laurylpyridinium chloride, 2-octadecyl-hydroxyethyl- Imidazoline derivatives such as 2-imidazoline, N, N
Amine salts such as -diethyl-stearamide-methylamine hydrochloride and polyoxyethylene stearylamine.

Examples of the anionic surfactant include higher fatty acid salts such as sodium laurate, sodium stearate, and sodium oleate; alkyl sulfates such as sodium lauryl sulfate and sodium stearyl sulfate; sodium octyl alcohol sulfate; sodium lauryl alcohol sulfate. Higher alcohol sulfates such as sodium ester sodium, lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyls such as sodium isopropylnaphthalene sulfonate Alkyl diphenyls such as naphthalene sulfonates and sodium alkyl diphenyl ether disulfonate -Alkyl diester salts such as terdisulfonic acid salts, sodium lauryl phosphate and sodium stearyl phosphate, polyethylene oxide adducts of sodium lauryl ether sulfate, polyethylene oxide adducts of ammonium lauryl ether sulfate, and polyethylene oxide adducts of lauryl ether triethanolamine sulfate. Alkyl ether sulfates such as polyethylene oxide adducts of alkyl ether sulfate, sodium nonylphenyl ether sulfate and polyethylene oxide adducts, and alkyl ether phosphates such as polyethylene oxide adduct of sodium lauryl ether phosphate and the like. Polyethylene oxide adducts of sodium nonylphenyl ether phosphate It can be mentioned side adducts of polyethylene oxide adducts of alkyl phenyl ether phosphate salts such like.

Examples of the nonionic surfactant include polyethylene glycols such as polyethylene glycol and polyethylene glycol polypropylene glycol block copolymer, and polyethylene glycol alkyl such as polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol oleyl ether and polyethylene glycol behenyl ether. Ethers, polyethylene glycol polypropylene glycol cetyl ether, polyethylene glycol polypropylene glycol decyl tetradecyl ether, etc., polyethylene glycol polypropylene glycol alkyl ethers, polyethylene glycol octyl phenyl ether, polyethylene glycol nonyl phenyl ether, etc. Ethylene glycol alkyl phenyl ethers, ethylene glycol monostearate,
Polyethylene glycol fatty acid esters such as ethylene glycol distearate, diethylene glycol stearate, polyethylene glycol distearate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, glyceryl monomyristate, glyceryl monostearate, monoisostearin Glyceryl acid, glyceryl distearate, glyceryl monooleate, glycerin fatty acid esters such as glyceryl dioleate, and polyethylene oxide adducts thereof,
Sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate and the like, and their polyethylene oxide adducts, sorbit monolaurate, sorbit tetrastearate, hexastearin Sorbitol fatty acid esters such as sorbit acid, sorbit tetraoleate,
And polyethylene oxide adducts thereof and castor oil polyethylene oxide adducts.

As the amphoteric surfactant, N-lauryl-
N, N-dimethyl-N-carboxymethyl ammonium, N-stearyl-N, N-dimethyl-N-carboxymethyl ammonium, N-lauryl-N, N-dihydroxyethyl-N-carboxymethyl ammonium, N
-Lauryl-N, N, N-tris (carboxymethyl)
Betaine-type compounds such as ammonium, 2-alkyl-
Examples thereof include imidazolium salts such as N-carboxymethyl-N-hydroxyethyl imidazolium, and imidazolines such as imidazoline-N-sodium ethyl sulfonate and imidazoline-N-sodium ethyl sulfate.

Among the above surfactants, in the present invention, the quaternary ammonium salts as a cationic surfactant, the various polyethylene glycol derivatives as a nonionic surfactant, and the various polyethylenes Polyethylene oxide derivatives such as oxide adducts and betaine-type compounds as amphoteric surfactants are preferred.

In the negative photosensitive lithographic printing plate sensitive to an infrared laser according to the present invention, a photopolymerization initiator is preferably used, and (a) aromatic ketones are preferably used. , (B) an aromatic onium salt compound, (c) an organic peroxide, (d) a hexaarylbiimidazole compound, (e) a ketoxime ester compound, (f) an azinium compound, (g) an active ester compound, (h) ) Metallocene compounds, (i) trihaloalkyl-substituted compounds, and (j) organoboron compounds.

Preferred examples of (a) aromatic ketones as the photopolymerization initiator include compounds having a benzophenone skeleton or a thioxanthone skeleton, and JP-B-47-64.
An α-thiobenzophenone compound described in No. 16
Benzoin ether compounds described in JP-B-7-3981, α-substituted benzoin compounds described in JP-B-47-22326, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, Dialkoxybenzophenone described in JP-B-60-26483, benzoin ethers described in JP-B-60-26403, JP-A-62-81345, p-di (dimethylaminobenzoyl) benzene described in JP-A-2-21452, Thio-substituted aromatic ketones described in JP-A-61-194062; acylphosphine sulfides described in JP-B-2-9597; acylphosphines described in JP-B-2-9596; thioxanthones described in JP-B-63-61950; Coumarins described in JP-B-59-42864 are cited. Door can be.

Another example of the photopolymerization initiator is (b).
As aromatic onium salts, N, P, As, Sb, B
Aromatic onium salts of i, O, S, Se, Te or I are included. Such an aromatic onium salt is disclosed in
-14277, JP-B 52-14278, JP-B-5
Compounds described in JP-A No. 2-1279 and the like can be mentioned.

Another example of the photopolymerization initiator which is preferably used in the photosensitive lithographic printing plate according to the present invention is (c) an organic compound having at least one oxygen-oxygen bond in the molecule. , But includes, for example,
3,3 ', 4,4'-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra- (t-amylperoxycarbonyl) benzophenone, 3,3 ', 4 , 4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ', 4
4'-tetra (t-octylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (cumylperoxycarbonyl) benzophenone, 3,3', 4
Peroxide esters such as 4'-tetra (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate are preferred.

Other examples of the photopolymerization initiator which is preferably used in connection with the present invention include (d) hexaarylbiimidazole, which is described in JP-B-45-37377 and JP-B-sho-4.
4-85516 lophine dimers, for example, 2,2'-bis (o-chlorophenyl) -4,4 ',
5,5'-tetraphenylbiimidazole, 2,2'-
Bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p
-Dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole , 2,2'-bis (o, o '
-Dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2 '-Bis (o-methylphenyl)-
4,4 ', 5,5'-tetraphenylbiimidazole,
2,2'-bis (o-trifluoromethylphenyl)-
4,4 ', 5,5'-tetraphenylbiimidazole and the like.

Other examples of the photopolymerization initiator preferably used in the photosensitive lithographic printing plate according to the present invention include (e) ketoxime esters such as 3-benzoyloxyiminobutan-2-one, Acetoxy iminobutan-2-
On, 3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentan-3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2
-Benzoyloxyimino-1-phenylpropane-1-
On, 3-p-toluenesulfonyloxyiminobutan-2-one, 2-ethoxycarbonyloxyimino-1
-Phenylpropan-1-one and the like.

Another example of the photopolymerization initiator (f), which is an azinium salt compound, is disclosed in JP-A-63-138345.
JP-A-63-142345, JP-A-63-142
No. 346, JP-A-63-143537 and JP-B-46-43363.

Examples of the (g) active ester compound which is another example of the photopolymerization initiator include imide sulfonate compounds described in JP-B-62-6223 and JP-B-63-14340.
And active sulfonates described in JP-A-59-174831.

As another example of the metallocene compound (h) which is another example of the photopolymerization initiator, see JP-A-59-152396.
JP-A-61-151197, JP-A-63-414
No. 84, JP-A-2-249, JP-A-2-4705 and the titanocene compounds described in JP-A-1-30445.
No. 3 and JP-A-1-152109.

Another example of the photopolymerization initiator is (i) a trihaloalkyl-substituted compound. The trihaloalkyl-substituted compound referred to herein is, specifically, a compound having at least one trihaloalkyl group such as a trichloromethyl group and a tribromomethyl group in a molecule. Preferred examples include the trihaloalkyl group. Examples of the compound bonded to the nitrogen heterocyclic group include an s-triazine derivative and an oxadiazole derivative, or a trihaloalkylsulfonyl compound in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocycle through a sulfonyl group. No.

Particularly preferred photopolymerization initiators for use in the negative-working infrared laser-sensitive lithographic printing plate according to the present invention include (j) organoboron compounds. In particular, compounds having an organoboron anion represented by Chemical Formula 1 are used. Is preferred.

[0029]

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In the chemical formula 1, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different and each represents an alkyl group,
Represents an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, or a heterocyclic group. Of these, it is particularly preferred that one of R ₁ , R ₂ , R ₃ and R ₄ is an alkyl group and the other substituent is an aryl group.

In the above-mentioned organic boron anion, a cation which forms a salt with the organic boron anion simultaneously exists. In this case, the cation includes an alkali metal ion and an onium ion. Onium salts include ammonium, sulfonium, monodonium and phosphonium compounds. When a salt of an alkali metal ion or an onium compound with an organic boron anion is used, a sensitizing dye is separately added to impart photosensitivity in the wavelength range of light absorbed by the dye.

One of the preferred embodiments for use in the negative photosensitive lithographic printing plate according to the present invention is a photosensitive lithographic printing plate containing an organic boron salt together with a dye sensitizing with infrared light. The organic boron salt does not exhibit sensitivity to the wavelength region of infrared light, and exhibits sensitivity to light in such a wavelength region only by adding a sensitizing dye.

The organic boron salt in this case is a salt containing an organic boron anion represented by the above-mentioned formula 1, and as the cation forming the salt, an alkali metal ion and an onium compound are preferably used. Particularly preferred examples are as onium salts with organic boron anions,
Examples include ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Examples of particularly preferred organic boron salts are shown in Chemical formulas 2 and 3.

[0034]

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[0035]

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The ratio of the photopolymerization initiator in the composition of the photoreceptor formed on the photosensitive lithographic printing plate has a preferable range, and the photopolymerization initiator is 0 in 100 parts by weight of the total photosensitive composition. It is preferably contained in the range of 0.1 to 50 parts by weight.

The sensitizing dye preferably used in the negative type infrared laser-sensitive lithographic printing plate according to the present invention includes cationic dyes, anionic dyes and neutral dyes having no charge, such as merocyanine, coumarin and xanthene. , Thioxanthene, azo dyes and the like can be used. Among these, particularly preferred examples are cyanine as a cationic dye, carbocyanine, hemicyanine, methine, polymethine, triarylmethane, indoline, azine, thiazine, xanthene, oxazine, oxazine, acridine, rhodamine and azamethine dyes. is there. In combination with these cationic dyes, they are particularly preferably used because of their high sensitivity and excellent storage stability.
Among the above sensitizing dyes, 750 nm particularly related to the present invention.
In a system for imparting photosensitivity to light in the above-mentioned infrared light wavelength region, it is necessary to have absorption in such a wavelength region as a sensitizing dye. 4 and 5

[0038]

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[0039]

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There is a preferable range in the quantitative ratio between the sensitizing dye and the photopolymerization initiator as described above. The photopolymerization initiator is used in an amount of from 0.01 part by weight to 1 part by weight of the sensitizing dye.
It is preferably used in the range of 00 parts by weight, and more preferably the photopolymerization initiator is used in the range of 0.1 to 50 parts by weight.

In the negative type infrared laser-sensitive lithographic printing plate according to the present invention, it is preferable that the photosensitive layer contains an ethylenically unsaturated compound.
A polymerizable compound having two or more polymerizable double bonds in a molecule is exemplified. Examples of preferred ethylenically unsaturated compounds include 1,4-butanediol diacrylate,
1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate, ethylene glycol glycerol triacrylate, glycerol epoxy triacrylate, trimethylolpropane triacrylate And polyfunctional acrylic monomers such as pentaerythritol triacrylate and pentaerythritol tetraacrylate.

Alternatively, instead of the above polymerizable compounds, oligomers having radical polymerizability are also preferably used, and polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meta) may be used as various oligomers having acryloyl or methacryloyl groups introduced. ) Acrylates and the like are similarly used, but these can also be preferably used as ethylenically unsaturated compounds.

Alternatively, a more preferred ethylenically unsaturated compound is a styrene derivative. When a compound having two or more styryl groups in the molecule is used, the re-generation of styryl radicals generated by the generated radicals is preferred. Since crosslinking is effectively performed by bonding, it is extremely preferable for producing a highly sensitive negative photosensitive material. Particularly preferred examples of the ethylenically unsaturated compound include the examples shown in Chemical formulas 6 to 8.

[0044]

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[0045]

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[0046]

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There is a preferred range for the proportion of the above-mentioned ethylenically unsaturated compound in the photosensitive composition, and 1 part by weight to 60 parts by weight of the ethylenically unsaturated compound in 100 parts by weight of the total photosensitive composition. It is preferably contained in the range of 5 parts by weight, more preferably in the range of 5 parts by weight to 50 parts by weight.

In the negative type infrared laser-sensitive lithographic printing plate according to the present invention, the polymer binder contained in the photosensitive layer is preferably soluble in the developer according to the present invention, and particularly, an alkali having a carboxyl group. Preferably, it is a soluble polymer. An example of such a polymer is a polymer containing a carboxyl group-containing monomer as a copolymer component. In this case, the ratio of the carboxyl group-containing monomer contained in the copolymer composition is 5% by weight in a total composition of 100% by weight. % Or less and 99% by weight or less, and below this ratio, the copolymer may not be dissolved in the aqueous alkaline solution.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, crotonic acid, maleic acid, fumaric acid, monoalkyl maleate, and fumaric acid. Examples include acid monoalkyl esters, 4-carboxystyrene, and the like.

The monomers for forming a copolymer together with the carboxyl group-containing monomer as described above include:
Styrene, 4-methylstyrene, -hydroxystyrene, monoacetoxystyrene, -carboxystyrene,
Monoaminostyrene, chloromethylstyrene, styrene derivatives such as -methoxystyrene, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, alkyl methacrylates such as dodecyl methacrylate, phenyl methacrylate,
Aryl methacrylate or alkyl aryl esters such as benzyl methacrylate, methacrylic acid 2
Methacrylates having an alkyleneoxy group such as hydroxyethyl, 2-hydroxypropyl methacrylate, methoxydiethylene glycol methacrylate monoester, methoxypolyethylene glycol methacrylate monoester, and polypropylene glycol methacrylate monoester; 2-dimethylamino methacrylate Ethyl, amino group-containing methacrylates such as 2-diethylaminoethyl methacrylate, or the same examples as the corresponding methacrylates as acrylates, or vinylphosphonic acid or the like as a monomer having a phosphate group, or Amino group-containing monomers such as allylamine and diallylamine, or vinyl sulfonic acid and its salts, allyl sulfonic acid and its salts, methallyl sulfonic acid And salts thereof, styrenesulfonic acid and salts thereof, monomers having a 2-acrylamido-2-methylpropane sulfonic acid and sulfonic acid groups of salts thereof, 4-vinylpyridine, 2-vinyl pyridine, N
Monomers having a nitrogen-containing heterocyclic ring, such as -vinylimidazole, -vinylcarbazole, or monomers having a quaternary ammonium base, such as 4-vinylbenzyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and dimethyl. Quaternized products of aminopropylacrylamide with methyl chloride, quaternized products of vinylimidazole with methyl chloride, 4-vinylbenzylpyridinium chloride, etc., or acrylonitrile, methacrylonitrile, acrylamide, methacrylamide,
Dimethyl acrylamide, diethyl acrylamide,
-Isopropyl acrylamide, diacetone acrylamide,-methylol acrylamide,-methoxyethyl acrylamide, acrylamide or methacrylamide derivatives such as 4-hydroxyphenylacrylamide, further acrylonitrile, methacrylonitrile,
Phenylmaleimide, hydroxyphenylmaleimide,
Vinyl acetate, vinyl chloroacetate, vinyl propionate,
Vinyl esters such as vinyl butyrate, vinyl stearate, and vinyl benzoate; vinyl ethers such as methyl vinyl ether and butyl vinyl ether; and others; Vinyltrimethoxysilane,
In the negative photosensitive lithographic printing plate of the present invention, a copolymer containing various monomers such as glycidyl methacrylate together with the above-mentioned carboxyl group-containing monomer alone or in any combination thereof is preferably used. It can be used as a molecular binder.

In the structure of the above-mentioned polymer binder having a carboxyl group, a case where a substituent having reactivity to a radical generated from a photopolymerization initiator is preferably used.
For example, when a polymerizable double bond is introduced into a polymer side chain, it is particularly preferably used because a highly sensitive negative photosensitive composition can be obtained. Furthermore, when the polymerizable double bond in the side chain has a phenyl group substituted with a vinyl group as a polymerizable double bond, the vinyl radicals generated by the addition of the radicals are bonded to each other by recombination, resulting in high sensitivity. It is very preferable to provide a negative photosensitive material. Examples of preferred polymer binders are shown below. The numbers in the formula represent parts by weight of each repeating unit in the polymer.

[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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There is a preferred range for the molecular weight of the above-mentioned polymer binder, and the weight average molecular weight is 10%.
It is preferably in the range of 00 to 1,000,000, and more preferably in the range of 5000 to 500,000.

As another element constituting the negative type infrared laser-sensitive lithographic printing plate according to the present invention, a colorant can be preferably added. The colorant is used for the purpose of enhancing the visibility of the image area after the exposure and development processing, and various types of carbon black, phthalocyanine dye, triarylmethane dye, anthraquinone dye, azo dye, etc. Pigments and pigments can be used, and the binder weight is 0.005
It can be added preferably in the range of 0.5 parts by weight to 0.5 parts by weight.

Elements constituting the negative type infrared laser-sensitive lithographic printing plate according to the present invention may contain other elements in addition to the above-mentioned elements for various purposes. For example, it is also preferable to add inorganic fine particles or organic fine particles for the purpose of preventing blocking of the photosensitive lithographic printing plate or for improving the sharpness of an image after development.

Regarding the thickness of the photosensitive layer itself on the photosensitive lithographic printing plate, it is preferable to form the photosensitive layer on a support with a dry thickness in the range of 0.5 to 10 microns, and more preferably 1
It is extremely preferred that the thickness be in the range of from 5 microns to 5 microns in order to greatly improve the printing durability. The photosensitive layer is prepared by preparing a solution in which the above-mentioned various elements are mixed, applying the solution on a support using various known coating methods, and drying the solution. As the support, for example, a film or a polyethylene-coated paper may be used, but a more preferable support is an aluminum plate having a polished and anodized film.

In order to use the material having the photosensitive layer formed on the support as described above as a printing plate, it is subjected to infrared laser scanning exposure at a wavelength of 750 nm or more, and the exposed portion is crosslinked. By doing so, the solubility in the developing solution of the present invention is significantly reduced, and thus, the unexposed portions are efficiently eluted by the developing solution of the present invention as described above to form an image.

A particularly preferred laser light source for use in the infrared laser scanning exposure according to the present invention is a laser having an oscillation wavelength in the infrared region of 750 nm or more, and various semiconductor lasers, solid lasers such as a YAG laser and a glass laser are most preferred. preferable.

When developing a negative-type infrared laser-sensitive lithographic printing plate formed with the above-described structure, the development is performed at a developer temperature of 35 ° C. or lower using the developer according to the present invention. Is preferred. When the development is performed at a temperature higher than this, the permeation of the developing solution into the image area becomes remarkable, and the image area may be damaged or the image may be missing. When printing is performed using a material, the printing durability may be significantly reduced, which is not preferable.

When developing a negative photosensitive lithographic printing plate using the developing solution of the present invention, it is preferable to use an automatic developing apparatus. Preferably, the automatic developing device is provided with a developing section, a washing section and a rinsing section. In the developing section, when the developing solution is supplied to the surface of the plate material by a shower or the plate material is immersed in the developing solution. Preferably, a mechanism is provided. Further, it is also preferable to provide a mechanism for scraping off the non-image area from the surface of the photosensitive layer using a driven Molton roll or brush roll in the developing section. Alternatively, such a driven Molton roll or brush roll is preferably provided not in the developing section but in the subsequent washing section. In the rinsing section following the developing tank, it is preferable to carry out rinsing by using a shower or the like on the surface of the plate material, or by rinsing the plate material by immersing the plate material in a washing tank. it can. Further, a step of applying a liquid containing gum arabic or the like, which is called a gum liquid for plate surface protection, is provided in the rinsing section following the washing section, and a drying step is also preferably performed.

In the present invention, the moleton roll preferably provided in the developing section or the washing section is rayon,
A roll obtained by winding a Molton cloth formed by knitting fibers such as polypropylene and vinylon around a rubber roll of nitrile rubber, ethylene-propylene copolymer rubber, polyurethane or the like is preferably used. In this case, it is preferable that the fiber layer is formed as uniformly as possible on the surface of the moleton, and it is preferable that the surface of the photosensitive layer be uniformly rubbed by a method such as suppressing fluffing. Furthermore, the Moulton roll, as a drive roll, is rotated in the same or opposite direction to the transport direction without being synchronized with the transport speed of the transported plate material, effectively removing the residual film in the non-image area. Is preferably performed. When the drive roll rotates in the same direction as the transport direction, the relative speed between the drive roll surface and the transported plate material surface is not the same, and the effect of surface abrasion appears by increasing the relative speed of the drive roll surface. Preferred. In addition, even when the rotation direction of the drive roll is opposite to the transport direction, the surface is effectively rubbed, which is preferable.

In the present invention, as for the brush roll which is preferably provided in the developing section or the washing section, a brush roll using a brush wire such as nylon or polypropylene is preferable, and an implant roll brush and a channel roll brush are preferably used. Also in this case, the brush roll is preferably a driving roll driven by a driving device, and is preferably rotated in the same direction or in the opposite direction to the transport direction of the plate material to scrape the surface.

[0067]

EXAMPLES Hereinafter, the effects of the present invention will be further described based on examples. (Examples 1 to 5 and Comparative Examples 1 to 3) (Preparation of negative photosensitive lithographic printing plate) Thickness 0.24 mm
Using a grained anodized aluminum plate, a photosensitive coating solution having the following formulation was applied thereon by a roll coater so as to have a dry thickness of 2 microns. A photosensitive lithographic printing plate was prepared.
The size of the photosensitive lithographic printing plate material is 670 mm x 530 m
It was cut into a size of m and used.

<Photosensitive Coating Liquid> 10 parts by weight of polymer (P-1 in Chemical Formula 9) 2 parts by weight of photoradical generator (BC-6 in Chemical Formula 3) Polymerizable compound (C-5 in Chemical Formula 6) 3 Parts by weight Sensitizing dye (S-4 in Chemical Formula 4) 0.5 parts by weight Dioxane 70 parts by weight Cyclohexane 20 parts by weight

Synthesis Example 1 (Synthesis Example of Polymer of P-1 in Chemical Formula 9) Bismuthiol (2,5-dimercapto-1,3-4-
(Thiadiazole) (150 g) was suspended in 600 ml of methanol, and 101 g of triethylamine was gradually added while cooling to obtain a uniform solution. While keeping at room temperature, p-chloromethylstyrene (manufactured by Seimi Chemical, CMS
-14) was added dropwise over 10 minutes, and stirring was continued for another 3 hours. The reaction product was gradually precipitated, and after stirring, transferred to an ice bath and cooled to 10 ° C., and then the product was separated by suction filtration. After washing with methanol and drying in a vacuum drier for one day and night, the compound shown in Chemical formula 14 was obtained in a yield of 75%.

[0070]

Embedded image

In a 1-liter four-necked flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser, 70 g of methacrylic acid, 200 ml of ethanol, and 50 ml of distilled water were added, and 40 g of a monomer was added to a water bath with stirring. 110 g of triethylamine were added above. The mixture was heated to 70 ° C. in a nitrogen atmosphere, and 1 g of azobisisobutyronitrile (AIBN) was added at this temperature to initiate polymerization. After heating and stirring for 6 hours, the polymerization system was cooled to room temperature. Take out a portion (add dilute hydrochloric acid and p
H was adjusted to about 3 and this was opened in water.
Was obtained.

[0072]

Embedded image

100 g of 1,4-dioxane and 23 g of p-chloromethylstyrene were added to the remaining polymer solution from which a part was taken out, and the mixture was further stirred at room temperature for 15 hours. Thereafter, 85 g of concentrated hydrochloric acid (35-37% aqueous solution) was added, and after confirming that the pH of the system was 4 or less, the whole was transferred into 3 liters of distilled water. The precipitated polymer was separated by filtration, washed repeatedly with distilled water, and dried in a vacuum dryer for one day. The target polymer was obtained with a yield of 90%. The polymer was found to have a weight-average molecular weight of 90,000 (in terms of polystyrene) as determined by gel permeation chromatography, and supported by the structure of P-1 in polymerized 9 by proton NMR analysis.

Synthesis Example 2 (Synthesis example of C-5 in Chemical Formula 6) 89 g of thiocyanuric acid was suspended in 1.5 liter of methanol, and 84 g of potassium hydroxide was dissolved while cooling.
A 0% aqueous solution was gradually added to obtain a uniform solution. to this,
At room temperature, 230 g of p-chloromethylstyrene
The solution was gradually dropped so as not to exceed 0 ° C. Although the product was precipitated shortly after the addition, stirring was continued, and after stirring for 3 hours, the product was separated by suction filtration. After washing with methanol and drying all day and night in a vacuum dryer,
A compound represented by C-5 in Chemical Formula 6 was obtained in a yield of 90%.

The photosensitive lithographic printing plate prepared by the above method was used as a plate setter PT-R manufactured by Dainippon Screen Mfg. Co., Ltd.
Using 4000, a drum rotation speed of 1000 rpm, a resolution of 2400 dpi, and a plate surface exposure energy of 150 mJ /
The test image was exposed under the conditions of cm ² and the image area of 20%. The plate material after exposure was subjected to a developing treatment under the following conditions using a developing solution having the following formulation.

As the aqueous solution of potassium silicate, an aqueous solution of potassium silicate manufactured by Tama Chemical Industry Co., Ltd. was used as a component in the developer. The content of SiO ₂ was 20% and the content of KOH was 10%. Used. The KOH was further added to the aqueous potassium silicate solution to adjust the ratios as shown in Tables 1 and 2 below. Furthermore, polyethylene glycol (addition mole number = 5) monostearate was added as a surfactant to 0.3.
%, And ion-exchanged water was added so that the total amount of the solution was 100 liters to prepare a developer.

[0077]

[Table 1]

[0078]

[Table 2]

The development was carried out using PD-912-M manufactured by Dainippon Screen Mfg. Co., Ltd. as an automatic developing device for carrying out the development. As the developing solution, the developing solution prepared above was used. The PD-912-M has a mechanism in which a molton roll, which is a driving roll, is installed in a developing tank, and a plate material surface is rubbed in a developing solution. The rotation direction of the Molton roll, which is the drive roll, was the same as the transport direction, and the surface was rubbed by rotating at a relative speed approximately twice as high as the transport speed of the plate material. A mechanism for supplying a gum solution is provided in the final processing section. As the gum solution, a solution obtained by diluting Niken Ultra PS gum manufactured by Niken Chemical Laboratory Co., Ltd. one-to-one with water was used.

Into the developing tank, 18 liters of the developing solution were charged, and 30 ml of the same developing solution was replenished per plate as a replenishing solution. The washing water and the gum solution were supplied in a form circulating from a tank installed outside the automatic developing apparatus. The conditions for immersion in the developer were set at a liquid temperature of 32 ° C. and the immersion time was set to 14 seconds.
An average of 100 plates of the exposed photosensitive lithographic printing plates prepared above were processed per day.

The printing material subjected to the above-described processing was evaluated for printing under the following conditions. The printing machine used was Ryobi-560, the printing ink used was F Gloss Black B manufactured by Dainippon Ink and the fountain solution was a commercially available fountain solution diluted and used. As a printing evaluation item, the number of printed sheets until the ink density transferred to the paper from the start of printing was sufficient and stabilized was determined as the ink run, and the smaller the number, the better the evaluation. The printing durability was evaluated based on the number of prints until minute dots and fine lines in the test image began to be lost. The presence or absence of background stain was visually determined based on the presence or absence of background stain on the printed matter. Tables 3 and 4 also show the print evaluation results when the processing was continued. In addition, Comparative Examples 1-3
In Comparative Example 1, as described later in the processing on the first day, poor elution occurred in Comparative Examples 1 and 3, and in Comparative Example 2, remarkable omission of an image portion was observed. Therefore, no further development processing was performed.

[0082]

[Table 3]

[0083]

[Table 4]

In addition to the above evaluations, the image quality of the printing plate developed on each processing day was evaluated. The evaluation items were to confirm whether halftone dots in the range of 1% to 99% were reproduced on the plate material as a reproduction range of 133 halftone dots, to confirm that 20 micron fine lines were uniformly reproduced, and to check on the image. The presence or absence of a scratch and the presence or absence of a residual film remaining in a non-image portion were visually determined. The results are shown in Table 5. When the developing solutions of Examples 1 to 5 were used, a plate material having good image quality was stably obtained through the running test in each case. On the other hand, in Comparative Examples 1 and 3, poor elution occurred in the development processing on the first day, and net clogging was remarkable. Also,
Also in Comparative Example 2, the loss of the image portion was remarkable in the first development, and the halftone portion also had uneven reproducibility. Table 6 summarizes the results of Comparative Examples 1 to 3.

[0085]

[Table 5]

[0086]

[Table 6]

Comparative Example 4 Development was carried out in exactly the same manner as in Examples 1 to 5 above, using a 6% aqueous sodium metasilicate solution as a developing solution. And printing was not possible.

Comparative Example 5 As a developer, JP-A-6-282079 describes
The developer described in Example 1 (SiO ₂ = 1.35%,
_{KOH = 2.0%, SiO 2 /} K 2 O = 1.2, and polyoxyethylene (addition molar number = 12) sorbitol using contains) 0.02% exactly as in Example 1-5 When development was carried out in the same manner, remarkable residual film residue (elution failure) occurred in the first development, and printing was impossible.

[0089]

According to the developing solution of the present invention, when developing a negative photosensitive lithographic printing plate having photosensitivity to an infrared laser, the image quality is excellent, there is no generation of background stain at the time of printing, and there is no resistance. Provides a printing plate with excellent printing power.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/038 501 G03F 7/038 501

Claims (3)

[Claims] When developing a negative photosensitive lithographic printing plate exposed to an infrared laser using an alkaline developing solution without performing heat treatment after exposure, a surfactant, an alkali metal silicic acid is used as the alkaline developing solution. Containing silicates and alkali metal hydroxides and in the alkali metal silicate
The concentration of O ₂ is in the range of 1 to 4% by weight, the concentration of alkali metal hydroxide is in the range of 2 to 5% by weight, and the molar ratio of SiO ₂ / M ₂ O (M represents an alkali metal) is 0.5. A developer for a negative-type photosensitive lithographic printing plate for infrared laser, which is contained in the range of -1.1. 2. The developer according to claim 1, wherein the alkali metal silicate is a potassium salt. 3. The negative-working photosensitive lithographic printing plate comprises a photosensitive layer provided on an aluminum support, wherein the photosensitive layer has a polymerizable double bond in a side chain and a carboxyl group and an organic boron salt. A developing method, comprising developing the negative photosensitive lithographic printing plate with the alkaline developer of claim 1 or 2 at a temperature of 35 ° C. or lower.