JPH08254825A - Photosensitive planographic printer plate - Google Patents

Abstract

PURPOSE: To obtain a photosensitive planographic printing plate which has excellent printing durability and is hardly contaminated with time. CONSTITUTION: This printing plate has a photosensitive layer on a base body having a hydrophilic surface. The photosensitive layer contains (a) polymers having two or more monomers having unsatd. double bonds which can be crosslinked as the structural unit in the side chains, having >=20000 weight average mol.wt., and containing <=1wt.% component of <=3000 mol.wt., (b) sensitizer, and (c) org. compd. having two or more groups expressed by formula and having <=3000 mol.wt. The weight ratio (a)/(c) is 1/1 to 1/0.01. In formula, R<1> , R<2> are H, halogen atoms or alkyl groups, or R<1> and R<2> may be bonded to form a five or six member ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate, and more particularly to a lithographic printing plate having a photocrosslinking photosensitive layer having improved printing durability as a printing plate.

[0002]

2. Description of the Related Art Photocrosslinkable materials that crosslink by a cycloaddition reaction are well known, and many of these are used as a main component of a photosensitive composition used for producing a photosensitive lithographic printing plate and the like. Among these cross-linking materials, the photo-crosslinkable polymer having a maleimide group in the side chain has good stability and safety, but by itself, since it does not have sufficient photosensitivity in practice, in order to enhance photosensitivity. , Thioxanthones, benzophenones, Michler's ketones, anthraquinones, anthracenes, chrysene, p-dinitrobenzene, 2-nitrofluorene, JP-A-62-294238, JP-A-2-173646, JP-A-2-236552, JP-A-2-236552. The sensitizers described in JP-A-3-54566 and JP-A-6-107718 are used. Further, in order to secure an adhesive force with a support having a hydrophilic surface, it is described in JP-B-5-2227, JP-A-3-2864, JP-A-3-240061, and JP-A-4-274429. As described above, it is proposed to add a diazo resin to the photosensitive layer. However, the photosensitive lithographic printing plates obtained by these methods do not have sufficiently satisfactory printing durability.

Further, Japanese Patent Application Laid-Open No. 2-285349 describes that printing durability is improved by combining the photosensitive layer with an undercoat of a polymer compound having a phosphoric acid group. However, this method has a problem that when the photosensitive lithographic printing plate is aged, it is easily stained during printing.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a photosensitive lithographic printing plate which has excellent printing durability and is resistant to stains over time.

[0005]

As a result of intensive studies to achieve the above object, the present inventors have found that (a) an unsaturated double bond capable of cross-linking a side chain on a support having a hydrophilic surface. A polymer having two or more monomers having a bond as a constitutional unit, having a weight average molecular weight of 20,000 or more and a component having a molecular weight of 3,000 or less of 1% by weight or less, (b) a sensitizer, and (c) the following general It contains an organic compound having two or more groups represented by formula (I) and a molecular weight of 3,000 or less, and the weight ratio of polymer (a) / organic compound (c) is from 1/1 to 1 / 0.01. The present invention has been achieved by finding that the above object can be achieved by a photosensitive lithographic printing plate characterized by having a certain photosensitive layer.

[0006]

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[In the formula (I), R ¹ and R ² each represent a hydrogen atom, a halogen atom or an alkyl group, or R ¹ and R ²
May together form a 5-membered ring or a 6-membered ring. ]

Although the reason why the effect of the present invention is exhibited is not clear, the high molecular weight polymer (a) has many unreacted crosslinking groups because it has a high molecular weight and is hard to move in the photosensitive layer. On the other hand, when the organic compound (c) having two or more groups of the formula (I) and having a molecular weight of 3,000 or less is added, it participates in the cross-linking of the polymer (a), and therefore it is presumed that the curing will proceed further sufficiently. To be done.

The present invention will be described in detail below.
In the polymer represented by (a), as the group having a crosslinkable unsaturated double bond, in addition to the maleimide group represented by the general formula (I), the following groups described in JP-A-62-175730 Groups represented by general formulas (II) and (III),
Examples thereof include a group represented by the following general formula (IV) and a group represented by the general formula (V) described in JP-B-3-63740.

[0010]

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[In the formula (II), A represents an aryl group, a substituted aryl group, a furyl group or a thienyl group, X represents a hydrogen atom, a halogen atom, a phenyl group, an alkyl group, a cyano group or a carbonyl group, and n ₁ represents 0 or 1. ]

[0012]

[Chemical 4]

[In the formula (III), B represents a hydroxy group, an alkoxy group, an aryl group, a substituted aryl group or an alkyl group, Y represents a hydrogen atom, a halogen atom, a phenyl group, an alkyl group or a cyano group, and n ₂ represents 0 or 1. ]

[0014]

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[In the formula (IV), R ³ represents a hydrogen atom or a methyl group. ]

[0016]

[Chemical 6]

[In the formula (V), R ⁴ represents a hydrogen atom or a methyl group. ]

In the present invention, a photocrosslinkable polymer having a maleimide group in its side chain is preferably used, and in particular, the maleimide group represented by the general formula (I) and / or the general formula (I) is used.
Polymers having a group represented by V) in the side chain are preferred.
Here, the maleimide group represented by the general formula (I) is
When used as a side chain of a photocrosslinkable polymer, R
The alkyl groups of ¹ and R ² preferably have 1 to 4 carbon atoms, and a methyl group is particularly preferable. It is also preferable that R ¹ and R ² are taken together to form a 6-membered ring. The halogen atom is preferably a chlorine atom, a bromine atom or an iodine atom.

Such a polymer is disclosed in, for example, Japanese Patent Laid-Open Publication No.
2-988 (corresponding U.S. Pat. No. 4,079,041)
Gazette, West German Patent No. 2,626,769, European Patent No. 21,019, European Patent No. 3,552 and The Die Angewandte Mackromolekulare Chem.
i) 115 (1983), pages 163 to 181, JP-A-49-128991 to 49-128993, 50 to 5376 to 50-5380, and 53-52.
No. 98 to No. 53-5300, No. 50-50107,
51-47940, 52-13907, 50
-45076, 52-121700, 50-1
0884, 50-45087, 58-4395.
No. 1 and West German Patent Nos. 2,349,948 and 2,616,276.

In the present invention, among these, the average molecular weight of two or more maleimide groups per molecule is in the side chain, and the weight average molecular weight of polystyrene standard measured by GPC is 2 or less.
A component having a molecular weight of 30,000 or more and a molecular weight of 3,000 or less is 1% by weight or less is used. Such a polymer can be synthesized using, for example, the monomers represented by the following general formulas (A) to (C).

[0021]

[Chemical 7]

[In the formulas (A) to (C), R ¹¹ and R ¹² have the same meanings as R ¹ and R ^{2 in} the general formula (I), R ¹³ represents a hydrogen atom or a methyl group, and m ₁ , m ₂ and m ₃ are integers, preferably 1 to 6. ]

The photosensitive lithographic printing plate using these polymers is preferably environmentally safe to be developed with an alkaline aqueous developer containing substantially no organic solvent. Therefore, these polymers are soluble or swellable in alkaline water. It is preferably sex. Therefore, it is preferable to copolymerize a monomer having a group having a photopolymerizable unsaturated double bond or a side chain with a monomer having an alkali-soluble group.

As the alkali-soluble group, pKa is 14
The following acid groups are preferred. Specific examples of the monomer having such an alkali-soluble group include vinyl monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, and a -CONHSO ₂ -group represented by the following formula (D). A vinyl monomer containing a —SO ₂ NH— group represented by the following formula (E), a phenolic hydroxyl group-containing vinyl monomer represented by the following formula (F), and a formula (G) In addition to the vinyl monomer having a phosphoric acid group or a phosphonic acid group as shown, maleic anhydride, itaconic anhydride and the like are exemplified.

[0025]

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[In the formula (D), R ¹⁴ represents a hydrogen atom or a methyl group, and R ¹⁵ has 1 carbon atom which may have a substituent.
It represents 2 or less hydrocarbon groups. Note that a methyl group, a phenyl group, and a tolyl group are preferable as R ¹⁵ .

[0027]

[Chemical 9]

[In the formula (E), R ¹⁶ represents a hydrogen atom or a methyl group, and R ¹⁷ represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms which may have a substituent. ] R ¹⁷ is preferably a hydrogen atom, a methyl group,
A phenyl group and a tolyl group.

[0029]

[Chemical 10]

[In the formula (F), R ¹⁸ represents a hydrogen atom or a methyl group. ]

[0031]

[Chemical 11]

[In the formula (G), R ¹⁹ represents a hydrogen atom or a methyl group, and R ²⁰ has 1 carbon atom which may have a substituent.
It represents a hydrocarbon linking group of 2 or less, and Z represents an oxygen atom or a single bond. ] R ²⁰ is preferably an alkylene group having 1 to 6 carbon atoms or a phenylene group.

The monomer having an alkali-soluble group and the monomer having a group having a photocrosslinkable or polymerizable unsaturated double bond are 10/90 to 70/30 (molar ratio), preferably 20/80. The photocrosslinkable polymer (a) of the present invention can be easily obtained by copolymerizing at a ratio of 60/40 (molar ratio). The acid value of the polymer (a) is preferably in the range of 30 to 500, and particularly preferably 50 to 300.

Among these photo-crosslinkable polymers, di-
Die Angewand
te Mackromolekulare Chemi) 128 (1984) 71
Copolymers of N- [2-methacryloyloxy) alkyl] -2,3-dimethylmaleimide with methacrylic acid or acrylic acid as described on page 91 are useful. Furthermore, by synthesizing the vinyl monomer of the third component at the time of synthesizing the copolymer, a multi-component copolymer suitable for the purpose can be easily synthesized. For example, by using an alkyl methacrylate or an alkyl acrylate having a glass transition point of a homopolymer of room temperature or lower as a vinyl monomer of the third component, flexibility can be given to the copolymer.

As the polymer (a) used in the present invention, the polystyrene standard weight average molecular weight using GPC is 20,000 or more, preferably 20,000 to 500,000, particularly preferably 20,000 to 300,000. The thing of is desirable. Further, as the polymer (a), it is also possible to use a combination of two or more corresponding polymers.

As the sensitizer of (b), a triplet sensitizer having a maximum absorption that actually allows sufficient light absorption in a range of 300 nm or more is preferable. Examples of such sensitizers include benzophenone derivatives, benzanthrone derivatives, quinones, aromatic nitro compounds, naphthothiazoline derivatives, benzothiazoline derivatives, thioxanthones,
Examples thereof include naphthothiazole derivatives, ketocoumarin compounds, benzothiazole derivatives, naphthofuranone compounds, pyrylium salts and thiapyrylium salts.

Specifically, Michler's ketone, N, N'-diethylaminobenzophenone, benzanthrone, (3
-Methyl-1,3-diaza-1,9-benz) anthrone picramide, 5-nitroacenaphthene, 2-chlorothioxanthone, 2-isopropylthioxanthone, dimethylthioxanthone, methylthioxanthone-1-ethylcarboxylate, 2-nitro Fluorene, 2-dibenzoylmethylene-3-methylnaphthothiazoline, 3,
In addition to 3-carbonyl-bis (7-diethylaminocoumarin), 2,4,6-triphenylthiapyrylium perchlorate, 2- (p-chlorobenzoyl) naphthothiazole, JP-B-45-8832 and JP-A-52-52 -12
9791, JP-A-62-294238, JP-A-2-
173646, JP-A-2-131236, European Patent 368327, JP-A-2-236552, JP-A-3.
Examples thereof include sensitizers described in JP-A-54566 and JP-A-6-107718.

Of these, preferred is JP-A-2-236.
No. 552, JP-A-3-54566, and JP-A-6-107.
The sensitizers described in the respective specifications of Japanese Patent No. 718, particularly preferably, as the alkali-soluble group in the molecule, -C, as described in JP-A-6-107718.
OOH group, -NHSO ₂ R ²¹ group, -CONHCOR
²¹ group, -CONHSO ₂ R ²¹ group (R ²¹ is an alkyl group, an aromatic group or an alkyl aromatic group) sensitizer comprising one or more. The amount of these sensitizers added is 1 to 20% by weight, preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight, based on the total composition of the photosensitive layer.

In the present invention, an organic compound (c) having two or more groups represented by the following general formula (I) and having a molecular weight of 3,000 or less.
Have.

[0040]

[Chemical 12]

[In the formula (I), R ¹ and R ² each represent a hydrogen atom, a halogen atom or an alkyl group, or R ¹ and R ²
May together form a 5-membered ring or a 6-membered ring. ]

Here, the alkyl group of R ¹ and R ² preferably has 1 to 4 carbon atoms, and particularly preferably a methyl group. It is also preferable that R ¹ and R ² are taken together to form a 6-membered ring. As a halogen atom, a chlorine atom,
A bromine atom or an iodine atom is preferable.

Further, the organic compound (c) preferably further has an alkali-soluble group, and as the alkali-soluble group, the same pKa as described in the polymer (a) is used.
Is preferably 14 or less. Specifically, as the organic compound (c), the OH group of aldonic acid or aldaric acid is 2
One or more, esterified with the following compound (i)

[0044]

[Chemical 13]

Alternatively, one obtained by esterifying two or more COOH groups of a polymethacrylic acid oligomer having a molecular weight of 3,000 or less with the following compound (ii)

[0046]

Embedded image

And the like. In compound (i) and compound (ii), R ¹ and R ² are as defined above, and a methyl group is particularly preferable.

The molecular weight of the organic compound (c) is 3000 or less, preferably 500 to 3000. Further, the usage ratio (weight) of the polymer (a) and the organic compound (c)
Is 1/1 to 1 / 0.01, especially 1 / 0.5 to 1
It is preferably in the range of /0.02. As the organic compound (c), two or more corresponding compounds may be used in combination. At this time, the use ratio (weight) of the polymer (a) and the organic compound (c) may be the above ratio as a combined value of two or more kinds of the organic compounds (c).

The photosensitive layer of the present invention preferably further contains a diazo resin. Examples of the diazo resin include co-condensates of aromatic diazonium compounds and aldehydes. As a specific example, Japanese Patent Publication No. 49-48001,
The diazo resins described in JP-B No. 50-7481, JP-B-5-2227, JP-A-3-2864, JP-A-3-240061, and JP-A-4-274429 are mentioned.

Among them, diazo resins described in JP-A-3-240061, which are co-condensed with an aromatic compound having at least one carboxyl group, and JP-A-3-2864, Such as a diazo resin condensed with an aldehyde having a carboxyl group,
A diazo resin having a carboxyl group introduced into the molecule is preferable. The amount of these diazo resins added is 0.1 to 30% by weight, preferably 0.5 to 10% by weight, and particularly preferably 1 to 5% by weight, based on the total composition of the photosensitive layer.

The photosensitive layer of the present invention may further contain a binder, if desired, and it is usually selected appropriately from linear organic polymers. Specific examples of the binder include phenol formaldehyde resin, cresol formaldehyde resin, phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene and carboxyl group-containing epoxy resin, polyacetal resin, acrylic resin, methacrylic resin, carboxyl group-containing polyurethane. Known alkali-soluble polymer compounds such as resins can be used. The alkali-soluble polymer compound is used in an amount of 50% by weight or less based on the total composition.

If desired, various additives may be added to the photosensitive layer of the present invention. For example, a polyfunctional monomer having two or more radically polymerizable ethylenic double bonds in the molecule can be added. Such compounds include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate,
Hexanediol di (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta-erythritol and dipenerythritol tri-, tetra- or hexa (meth) acrylate and the like can be mentioned. The amount of these polyfunctional monomers added is 1 in the total composition of the photosensitive layer.
It is 0% by weight or less.

Further, for the purpose of coloring the photosensitive layer, dyes or pigments such as diphenylmethane dyes, triphenylmethane dyes, thiazine dyes, oxazine dyes,
It is preferable to add a xanthone dye, an anthraquinone dye, an iminonaphthoquinone dye, an azomethine dye, an azo dye, titanium oxide, iron oxide, carbon black, a phthalocyanine pigment, an azo pigment, and the like. Further, as a print-out agent, for example, a combination of a photoacid generator or photooxidant such as a trihalomethyl group-containing compound, a diazo monomer, a sulfonium salt or an iodonium salt, a pH indicator and a leuco dye may be added to the photosensitive layer. .

Further, the photosensitive layer of the present invention may contain a plasticizer and the like. As the plasticizer, dialkyl phthalate such as dibutyl phthalate and dihexyl phthalate, oligoethylene glycol alkyl ester, phosphate plasticizer and the like can be used. Further, various acid compounds as stabilizers for diazo resins and acid group-containing compounds soluble in alkaline water for promoting development may be used. Further, the photosensitive layer of the present invention, by adding an oil sensitizer, a surfactant, a fluorine compound, a silica compound, etc.,
It is also possible to change the properties of the surface of the photosensitive layer.

Further, it is preferable to add a thermal polymerization inhibitor and an antioxidant to the photosensitive layer. For example, hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol. , Benzoquinone, 4,4'-thiobis (3-methyl-6-t-
Butylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, etc. are useful.

The photosensitive layer of the photosensitive lithographic printing plate of the present invention is dissolved in a solvent which dissolves each of the above components and coated on a support. As the solvent used here, methanol, ethanol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, ethylene dichloride, cyclohexanone, acetone, methyl ethyl ketone, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2- Methoxyethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N, N-
There are dimethylformamide, tetrahydrofuran, dioxane, dimethylsulfoxide, ethyl acetate, toluene, methyl lactate, ethyl lactate and the like, and these solvents can be used alone or as a mixture. Also, a small amount of water may be added to these solvents or mixed solvents. The concentration (solid content) of the above components in the solvent is 1 to 50% by weight.

When the photosensitive solution dissolved in these solvents is applied and dried, it is desirable to dry at 50 ° C to 120 ° C. The drying method may be such that the temperature is first lowered and pre-dried and then dried at a high temperature, but it may be directly dried at a high temperature by selecting an appropriate solvent and concentration. The coating amount of the photosensitive layer after drying, the range of 0.1g / m ² ~10g / m ² are suitable, preferably from ^{0.5g / m 2 ~5g / m 2} .

In the present invention, an intermediate layer may be optionally added for the purpose of increasing the adhesion between the support and the photosensitive layer, preventing the photosensitive layer from remaining after development, or preventing halation. It may be provided. In order to improve the adhesion, the intermediate layer generally comprises a diazo resin, a phosphoric acid compound adsorbed on aluminum, a silane coupling agent, or the like. The intermediate layer made of a highly soluble substance so that the photosensitive layer does not remain in the developing solution is generally made of a polymer having a good solubility or a water-soluble polymer. Furthermore, for antihalation, the intermediate layer generally contains dyes and UV absorbers. The thickness of the intermediate layer is arbitrary, and must be a thickness capable of performing a uniform bond-forming reaction with the upper photosensitive layer upon exposure. Usually about 1 to 1 as a dry solid
Applying a rate of 200 mg / m ² good, 5 to 40 mg / m ² is particularly favorable.

The co-condensed diazo resin used in the photosensitive layer of the present invention or a photocrosslinking polymer may be added to the intermediate layer. The proportion of these used is 5 to 100% by weight of the intermediate layer,
It is preferably 10 to 100% by weight. In the intermediate layer, if necessary, a sensitizer, a diazo stabilizer, a polymer binder,
In addition to the antihalation agent and the surfactant, various additives may be added. To provide the intermediate layer, the above compound is dissolved in any solvent at a desired concentration, and it is applied or dipped,
It is then obtained by drying.

The surface of the photosensitive layer provided as described above is preferably matted in order to shorten the vacuuming time during contact exposure using a vacuum baking frame and to prevent burning blur. Specifically, a method of providing a mat layer as described in JP-A-50-125805, JP-A-58-182636 and JP-B-57-6582, and JP-B-62-62337 are described. Examples of the method include heat fusion of such solid powder.

The support having a hydrophilic surface used in the present invention is preferably a dimensionally stable plate-like material. Such dimensionally stable plate-like materials include those conventionally used as a support for a printing plate, and they can be suitably used in the present invention. Examples of such a support include paper, paper laminated with plastics (for example, polyethylene, polypropylene, polystyrene, etc.),
Metal plates such as aluminum (including aluminum alloy), zinc, copper, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate , A plastic film such as polyvinyl acetal, and a paper or plastic film on which the above metal is laminated or vapor deposited. Among these supports, the aluminum plate is preferable because it is extremely stable in dimension, is inexpensive, and has particularly good adhesion to the photosensitive layer of the present invention. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-B-48-18327 is also preferable.

In the case of a metal, particularly an aluminum support, it is preferable that surface treatment such as graining treatment and anodic oxidation treatment be performed. In order to enhance the hydrophilicity of the surface, it is preferable to perform a dipping treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate or the like. As described in U.S. Pat. No. 2,714,066, an aluminum plate which has been grained and then immersed in an aqueous sodium silicate solution, JP-B-47-512.
It is also preferable to use an aluminum plate which has been subjected to anodizing treatment as described in JP-A-2005-53187 and then subjected to immersion treatment in an aqueous solution of an alkali metal silicate.

Further, silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. Furthermore, Japanese Patent Publication No. 46-27481 and Japanese Unexamined Patent Publication No.
It is also useful to use a combination of the electrolytic grained support as disclosed in JP-A No. 2-58602 and JP-A No. 52-30503 with the above anodizing treatment and sodium silicate treatment. Further, as disclosed in JP-A-56-28893, a brush grain, an electrolytic grain, an anodic oxidation treatment, and a sodium silicate treatment which are sequentially performed are also preferable. It is also preferable that after these treatments, a water-soluble resin, such as polyvinyl phosphonic acid, a polymer or copolymer having a sulfonic acid group in its side chain, is undercoated. Further, those disclosed in JP-A-2-23348 and Japanese Patent Application No. 2-151858 are also suitable. These hydrophilic treatments are
In addition to being applied to make the surface of the support hydrophilic, it is applied to prevent harmful reaction with the photosensitive composition provided thereon and to improve the adhesion with the photosensitive layer. It

The photosensitive lithographic printing plate of the present invention is imagewise exposed by using a light source rich in ultraviolet rays such as a metal halide lamp, a high pressure mercury lamp and the like, and treated with a developing solution to remove the unexposed portion of the photosensitive layer, and finally. A lithographic printing plate is prepared by applying a desensitizing gum solution to the.

As a developing solution for the photosensitive composition of the present invention, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, triphosphoric acid can be used. Aqueous solutions of inorganic alkaline agents such as ammonium, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, etc. and aqueous solutions of organic amine compounds such as mono-, di- or triethanolamine are suitable, and their concentrations are suitable. 0.1 to 10% by weight, preferably 0.5 to 5% by weight
To be added.

If necessary, an organic solvent such as a surface-active agent or alcohol may be added to the alkaline aqueous solution. Preferable organic solvents include benzyl alcohol, 2-phenoxyethanol, 2-butoxyethanol, n-propyl alcohol and the like. Examples of the surfactant include anionic surfactants such as alkylnaphthalene sulfonate and sodium lauryl sulfate. In addition, diazo dissolving agent,
For example, it is also preferable to add a reducing substance such as a sulfite, a methylresorcin, or a pyrazolone compound. Also, U.S. Pat. Nos. 3,475,171 and 3,615,48
The thing described in each specification of No. 0 can be mentioned. Furthermore, JP-A-50-26601 and JP-B-56-
The developers described in Japanese Patent Nos. 39464 and 56-42860 are also excellent as developers for the photosensitive lithographic printing plate of the present invention.

However, when an organic solvent or the like is contained, there is a problem in hygiene such as toxicity and odor during work, a problem in safety such as flame and gas explosion, a problem in workability such as generation of bubbles, pollution due to waste liquid, etc. Therefore, it is preferable that the organic solvent does not substantially contain the organic solvent. In addition, "substantially does not contain an organic solvent" means that the organic solvent is not contained to the extent that causes inconvenience in view of the above-mentioned environmental health, safety, workability, etc., and in the present invention, The ratio of the substance in the composition is 2% by weight or less, preferably 1% by weight or less. As such an aqueous alkaline developer containing substantially no organic solvent, the positive type lithographic printing plate described in, for example, JP-A-59-84241 and JP-A-57-192952 is subjected to image exposure, The developer composition used in developing can be used.

Photosensitive lithographic printing plates using the photosensitive composition of the present invention are disclosed in JP-A-54-8002 and JP-A-55-1150.
Needless to say, the plate-making process may be carried out by the methods described in JP-B No. 45 and JP-A-59-58431. That is, after the development treatment, it may be washed with water and then subjected to a desensitizing treatment, a desensitizing treatment as it is, a treatment with an aqueous solution containing an acid, or a desensitizing treatment after a treatment with an aqueous solution containing an acid. Furthermore, in the developing step of this type of photosensitive lithographic printing plate, the aqueous alkali solution is consumed depending on the processing amount to reduce the alkali concentration, or the alkali concentration is reduced by air due to long-time operation of the automatic developer. Although the processing capacity is lowered, at that time, the Japanese Patent Laid-Open No. 54-6200
No. 4, No. 55-22759, No. 55-115039
No. 56-12645, No. 58-95349, No. 64-21451, JP-A-1-180548 and JP-A-2-3065, and a method of replenishing the treating ability. Can be done.

Further, the plate making process as described above is disclosed in
It is preferably carried out by an automatic developing machine as described in Nos. -7054 and 2-32357. The desensitizing gum that is optionally applied in the final step of the plate making process is described in JP-B Nos. 62-16834 and 62-25118.
No. 63-52600, JP-A No. 62-7595,
Those described in JP-A Nos. 62-11693 and 62-83194 are preferable. After development process, if necessary, erase, wash, desensitize process,
Further, for the purpose of increasing the strength of the image area, post-exposure, burning treatment, etc. can be performed.

[0070]

EXAMPLES The present invention will now be described in more detail with reference to examples. However, the present invention is not limited to these examples. Note that "%" indicates% by weight unless otherwise specified.

Example 1 An aluminum plate of 1S material having a thickness of 0.24 mm was sand-washed with a nylon brush and an aqueous suspension of 400 mesh pumice, and then washed thoroughly with water. This was immersed in a 10% aqueous sodium hydroxide solution at 70 ° C. for 60 seconds for etching, washed with running water and neutralized with 20% nitric acid, and then a sine wave with V _A = 12.7 V and V _C = 9.1 V. 170 coulomb / in 1% nitric acid aqueous solution using alternating waveform current
The electrolytic surface-roughening treatment was performed with the amount of electricity at the anode time of dm ² . Subsequently, it was immersed in a 30% aqueous solution of sulfuric acid, desmutted at 55 ° C. for 2 minutes, and then anodized in a 7% aqueous solution of sulfuric acid so that the coating amount of aluminum oxide was 1.8 g / m ² . Then add 1% to a 3% aqueous solution of sodium silicate at 70 ° C.
It was immersed for a minute, washed with water and dried. Applied using a whirler the photosensitive solution (I) shown below in the aluminum plate obtained as described above, 80 to a dry weight of 1.5 g / m ²
It was dried at 0 ° C for 2 minutes. The photosensitive lithographic printing plate thus obtained is referred to as a printing plate [A].

Photosensitive Solution (I) Methylmethacrylate / N- [6- (methacryloyloxy) hexyl] -2,3-dimethylmaleimide / methacrylic acid = 10/60/30 (molar ratio) copolymer {hereinafter polymer Called (a)} 4.0 g-Compound of the following structure (a) 1.0 g-The following sensitizer 0.3 g

[0073]

[Chemical 15]

Hexafluorophosphate salt of formaldehyde co-condensation polymer of 3-methoxy-4-diazodiphenylamine / phenoxyacetic acid = 1/1 (molar ratio) 0.1 g Megafac F-177 (Dainippon Ink and Chemicals, Inc.) Fluorine-based nonionic surfactant manufactured by Co., Ltd. 0.05 g-Ethyl violet counter anion converted to 6-hydroxy-β-naphthalene sulfonic acid 0.1 g-4-diazodiphenylamine dodecylbenzene sulfonate 1 g-Propylene glycol monomethyl ether 50 g-Methyl ethyl ketone 50 g

Comparative Example 1 Example 1 was repeated except that the compound (a) was not added at all in the photosensitive solution (I) and the amount of the polymer (a) was 5.0 g.
A photosensitive lithographic printing plate [B] was obtained in the same manner as.

The polymer (A) used in Example 1 and Comparative Example 1 was synthesized as in Synthesis Example 1 below.

Synthesis Example 1 500 ml of propylene glycol monomethyl ether as a reaction solvent was placed in a 2-liter four-necked flask equipped with a stirrer and stirring blades, a reflux condenser, a dropping funnel and a thermometer.
Was heated to 75 ° C. while purging with nitrogen. In a dropping funnel, 30.0 g of methyl methacrylate, 527.4 g of N- [6-methacryloyloxy) hexyl] -2,3-dimethylmaleimide, 77.4 g of methacrylic acid, and dimethyl 2,2'-azobisisobutyrate 13 as a polymerization initiator. .8g
Was dissolved in 500 ml of propylene glycol monomethyl ether and added, and this mixed solution was added dropwise to the flask over 2 hours while stirring. After completion of dropping, the reaction was further stirred at a reaction temperature of 75 ° C. for 5 hours to complete the reaction. After completion of heating, the reaction solution was added to 10 liters of water to cause precipitation, and after vacuum drying, 507.8 g (yield 80%) of a copolymerized polymer {polymer (A)} was obtained. The weight average molecular weight of this polymer (A) was measured by GPC and found to be 35,000 based on polystyrene standard. Also this polymer (A)
The component having a molecular weight of 3,000 or less was 0.5% or less of the whole.

A part of the above photosensitive lithographic printing plate was put at 45 ° C. for 8 hours.
It was allowed to stand for 2 days at 0% RH for forced aging. On the other hand, on the photosensitive lithographic printing plates [A] and [B] obtained as described above, a step wedge (density step 0.15,
Highest density 15 steps) and halftone dot negative film are overlaid, and printer FT26V2UPNS (light source; 2) manufactured by Nuark, Inc. in the US
50 count exposure with a KW metal halide lamp), soaking in the following developer (I) at 25 ° C. for 20 seconds, lightly rubbing with absorbent cotton, washing with water, and desensitizing treatment with the desensitizing solution described below. A lithographic printing plate was obtained.

Developer (I)-[SiO ₂ ] / [K ₂ O] molar ratio 1.2 potassium silicate 32 g-Ethylenediaminetetraacetic acid sodium salt 1 g-Water 967 g

Desensitizing liquid-Arabic gum 5 g-White dextrin 30 g-Ethylene glycol 10 g-Phosphoric acid 3 g-Water 952 g

Using these printing plates, high-quality paper was printed with a commercially available ink using an SOR printer manufactured by Heidelberg.
The performance at that time was as shown in Table 1. For the evaluation of developability and stain, a plate using a photosensitive lithographic printing plate that was forcibly aged was used.

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[Table 1]

The performance evaluations in Table 1 are as follows. The "developing property" was defined as good developing property when the unexposed portion of the photosensitive layer was not observed after development, and the remaining product was considered to be present.・ For the "maximum step number of step wedges", the part with the largest number where the image is recognized on the step wedge after development is taken as the maximum number of step wedges, and the sensitivity is doubled if this number is larger by two. Means・ "Dirt" indicates that ink is attached to the originally plain area during printing. -"Printing durability" is considered to be printing when the area where the ink originally adheres to the printed matter is faint or ink does not adhere. Therefore, the greater the number of sheets, the better the printing durability.

Example 2 In the photosensitive liquid (I) of Example 1, the polymer (A) 4.
Instead of 0 g, 2.5 g of polymer (a) and 1.5 g of a copolymer of allyl methacrylate / methacrylic acid = 70/30 (molar ratio) {hereinafter referred to as polymer (c)} were used, and compound (a) 1 A photosensitive lithographic printing plate [C] was obtained in the same manner as in Example 1 except that 1.0 g of the following compound (D) was used instead of 0.0 g to prepare the photosensitive solution (II).

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Embedded image

Comparative Example 2 Example except that the compound (d) was not added at all in the photosensitive solution (II), the amount of the polymer (a) was 3.12 g, and the amount of the polymer (c) was 1.88 g. A photosensitive lithographic printing plate [D] was obtained in the same manner as in 2.

The polymer (c) used in Example 2 and Comparative Example 2 was synthesized as in Synthesis Example 2 below.

Synthesis Example 2 500 ml of propylene glycol monomethyl ether as a reaction solvent was placed in a 2-liter four-necked flask equipped with a stirrer and stirring blades, a reflux condenser, a dropping funnel and a thermometer.
Was heated to 70 ° C. while purging with nitrogen. In a dropping funnel, 88.2 g of allyl methacrylate and 25.
8 g and 2,2'-azobis (2,4 as a polymerization initiator
-Dimethylvaleronitrile) (4.66 g) was dissolved and put in 500 ml of propylene glycol monomethyl ether, and the mixed solution was added dropwise to the flask over 2 hours while stirring. After completion of the dropping, the reaction was further stirred at a reaction temperature of 70 ° C. for 5 hours to complete the reaction. After heating, add 1 reaction mixture
Add to 0 liter of water to precipitate and after vacuum drying 91.2
g (yield 80%) of copolymerized polymer {Polymer (C)}
I got The weight average molecular weight of this polymer (c) is determined by GPC
Was measured with a polystyrene standard and found to be 30,000. Further, the content of the polymer (C) having a molecular weight of 3,000 or less was 0.5% or less of the whole.

The photosensitive lithographic printing plates [C] and [D] thus obtained were evaluated in the same manner as in Example 1.
The performance as shown in was obtained.

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[Table 2]

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The photosensitive lithographic printing plate of the present invention has excellent printing durability and is resistant to stains over time.

Claims (2)

[Claims] 1. On a support having a hydrophilic surface, (a)
A polymer having two or more monomers having a group having a crosslinkable unsaturated double bond in the side chain as a constitutional unit and having a weight average molecular weight of 20,000 or more and a molecular weight of 3,000 or less in an amount of 1% by weight or less. , (B) a sensitizer, and (c) an organic compound having two or more groups represented by the following general formula (I) and having a molecular weight of 3,000 or less, and a polymer (a) / organic compound (c) A photosensitive lithographic printing plate comprising a photosensitive layer having a weight ratio of 1/1 to 1 / 0.01. Embedded image [In the formula (I), R ¹ and R ² each represent a hydrogen atom, a halogen atom or an alkyl group, or R ¹ and R ² may be combined to form a 5-membered ring or a 6-membered ring. ] 2. The photosensitive lithographic printing plate according to claim 1, wherein the polymer (a) is a polymer having a group represented by the general formula (I) according to claim 1 in a side chain.