JPH0954435A - Photosensitive composition, photosensitive planographic printing plate and its plate making method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive compsn. and a photosensitive planographic printing plate having excellent blocking resistance, chemical resistance, especially durability against a washing oil for UV ink, which show excellent developing property even for development with an alkali soln. substantially containing no org. solvent, and moreover, which hardly produce an insoluble component in a developer and can be developed in a large amt. with a specified amt. of a developer. SOLUTION: This photosensitive compsn. consists of a compd. having addition polymerizable unsatd. bonds in the molecule, a photopolymn. initiator, a copolymerized diazo resin and an alkali-soluble or swellable binder polymer. The alkali-soluble or swellable binder polymer is such a polymer that >50 mol% of the repeating units which constitute the main chain of the polymer are the repeating units produced from a methacrylate deriv.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive composition, a photosensitive lithographic printing plate and a plate-making method thereof.

[0002]

BACKGROUND OF THE INVENTION A photosensitive lithographic printing plate is one in which a photosensitive layer is provided on a hydrophilic support. For example, in a negative photosensitive lithographic printing plate, actinic rays such as ultraviolet rays are formed on the hydrophilic support. To form a photosensitive layer which becomes insoluble by exposure to light and becomes ink-receptive.

In such a negative photosensitive lithographic printing plate, when the photosensitive layer is subjected to image exposure and then developed, the unexposed portion of the photosensitive layer is removed to expose the surface of the hydrophilic support while the exposed portion is exposed. The photosensitive layer remains on the support to form an ink receiving layer. In lithographic printing, the difference in the properties that the exposed portions are lipophilic and the unexposed portions are hydrophilic is used.

A photopolymerizable composition containing a compound having a polymerizable unsaturated bond in the molecule (photopolymerizable monomer) and a photopolymerization initiator is used in the photosensitive layer of the above negative type photosensitive lithographic printing plate. There is.

Many studies have been conducted on photopolymerizable compositions containing a compound having a polymerizable unsaturated bond (photopolymerizable monomer) and a photopolymerization initiator in these molecules, and a photopolymerizable composition on a support having a hydrophilic surface has been studied. There have also been reports on photosensitive lithographic printing plates coated with a photopolymerizable composition.

However, many of the compounds having a polymerizable unsaturated bond used in these photosensitive compositions are liquid compounds which are viscous liquids at room temperature. Therefore, the photosensitive compositions formed by coating these photosensitive compositions are used. In the case of a photosensitive lithographic printing plate having a layer, the surface of the photosensitive layer is sticky, and if the layers are stored under high temperature conditions, blocking may occur partially, so measures such as providing a protective layer on the photosensitive layer should be taken. I had to get it.

Further, in a photosensitive lithographic printing plate, in a development process after exposure, a method is generally used in which an unexposed portion of the photosensitive layer is eluted with an organic solvent or an alkaline aqueous solution containing an organic solvent to form an image. there were. The organic solvent used in the alkaline aqueous solution is used to obtain sufficient developability. However, organic solvents have an odor, and many of them are toxic, which poses a risk of fire, deteriorates the working environment of the plate making process, and adversely affects the health of workers. And further,
When the developer containing the organic solvent is discarded, it has many drawbacks such as being subject to BOD regulations, and the use of the organic solvent increases the cost. Therefore, the photosensitive lithographic printing plate In particular, it is desirable that sufficient developability be obtained without using an organic solvent. Further, it is desired that development can be stably performed for a long period of time.

The photosensitive lithographic printing plate thus prepared is washed with washing oil during printing, and it is desired that the photosensitive layer has resistance to these washing oils.

[0009]

OBJECTS OF THE INVENTION Therefore, the first object of the present invention is to provide a photosensitive composition having excellent blocking resistance.

A second object of the invention is chemical resistance, especially
It is to provide a photosensitive composition having excellent resistance to UV ink washing oil.

The third object of the present invention is to obtain excellent developability even in the development with an alkaline aqueous solution containing substantially no organic solvent, and moreover, it is difficult to form an insoluble component in the developing solution, and it is uniform. An object of the present invention is to provide a photosensitive lithographic printing plate that can be developed in a large amount with a developing solution.

[0012]

The above-mentioned objects of the present invention are: (1) (A) a compound having an addition-polymerizable unsaturated bond in the molecule, (B) a photopolymerization initiator, (C) a co-condensed diazo resin and (D). In a photosensitive composition comprising an alkali-soluble or swellable binder polymer, (D) the alkali-soluble or swellable binder polymer comprises a methacrylic acid derivative in which 50 mol% or more of the repeating units constituting the main chain of the binder polymer are A photosensitive composition, which is a binder polymer composed of repeating units of (2) The photosensitive composition as described in (1) above, wherein the methacrylic acid derivative is an alkyl ester of methacrylic acid. (3) The above (1) or (2), wherein the alkali-soluble or swellable binder polymer (D) is a binder polymer having a repeating unit from an addition polymerizable monomer having an aromatic hydroxyl group. The photosensitive composition of. (4) The photosensitive composition as described in (3) above, wherein the addition-polymerizable monomer having an aromatic hydroxyl group is a compound represented by the following general formula (1).

[0013]

Embedded image [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents —COO
-, -CONH-. n represents 0 or 1. (5) The (C) co-condensation diazo resin is a co-condensation product of diazodiphenylamine and an aromatic compound having at least one group selected from a carbonyl group and a sulfonyl group in the molecule. The photosensitive composition as described in (1) to (4) above. (6) The photosensitive composition according to the above (1) to (5), wherein the (C) co-condensed diazo resin is a co-condensed product of diazodiphenylamine and p-hydroxybenzoic acid. (7) Above (1) to (6) on a hydrophilic support.
A photosensitive lithographic printing plate comprising a layer of the photosensitive composition described. (8) The photosensitive lithographic printing plate as described in (7) above, wherein a protective layer is not provided on the layer of the photosensitive composition. (9) A method for making a photosensitive lithographic printing plate, which comprises developing the photosensitive lithographic printing plate described in (8) above with an alkaline aqueous solution having a pH of 12 or more and substantially containing no organic solvent. Achieved by

The present invention will be described in detail below.

The compound having an addition polymerizable unsaturated bond in the molecule used in the present invention is known, and in the photosensitive composition of the present invention, the known polymerizable unsaturated compound used in the photopolymerizable composition is used. Can be used and may have any chemical structure, but compounds having 2 or more addition-polymerizable unsaturated bonds in the molecule are preferable. Further, a polymerizable compound having two or more addition-polymerizable unsaturated bonds may be used in combination.

Examples of the compound having an addition-polymerizable unsaturated bond in the molecule include unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, unsaturated carboxylic acids and aromatic polyhydroxy compounds. And the esters obtained by the esterification reaction of the unsaturated carboxylic acid and polyvalent carboxylic acid and the above-mentioned aliphatic polyhydroxy compound, polyvalent hydroxy compound such as aromatic polyhydroxy compound, and the like. , JP Sho
59-71048, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate, hydroquinone di (meth) acrylate, glycerol di ( Examples thereof include (meth) acrylate, pyrogallol triacrylate, and 2,2-bis (4-acryloxydiethoxyphenyl) propane. Other examples include (meth) acrylamides such as ethylene bis (meth) acrylamide and hexamethylene bis (meth) acrylamide, vinyl urethane compounds and epoxy (meth) acrylates.

The amount of the compound having an addition-polymerizable unsaturated bond in the molecule used in the photopolymerizable composition of the present invention is usually 5 to 70% by weight, preferably 5 to 70% by weight based on the total solid content of the photopolymerizable composition. , 10 to 50% by weight.

The photopolymerization initiator that can be used in the present invention is not particularly limited, and conventionally known ones used in photopolymerizable compositions can be used. Examples thereof include benzoin, benzoin alkyl ether, benzophenone, anthraquinone, and the like.
Michler's ketone, a trihalomethyl-s-triazine-based compound, an oxadiazole-based compound, a complex system of biimidazole and Michler's ketone, a complex system of thioxanthone and an aromatic tertiary amine, and the like can all be suitably used.

As the photopolymerization initiator, a compound having absorption at the wavelength of the light source used for exposing the photosensitive lithographic printing plate is usually used.

In the present invention, the following are preferable as the photopolymerization initiator.

[0021]

Embedded image [R ¹ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, or a halogen. a and b are 0 ≦ a + b ≦ 4
Represents an integer. Specific examples include 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and isopropylthioxanthone.

[0022]

Embedded image [R ² , R ³ , and R ⁴ represent a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. Ar represents a substituted or unsubstituted phenylene group, naphthylene group or heterocyclic aromatic group. Specifically, ethyl p-dimethylaminobenzoate, p-
Isoamyl dimethylaminobenzoate and the like can be mentioned.

[0023]

Embedded image[Ar is a substituted or unsubstituted phenylene group, naphthyl
A heterocyclic group or a heterocyclic aromatic group. R^FiveIs a hydrogen source
Child, alkyl group, alkoxy group, dialkylamino group,
Alkylthio group, hydroxy group, halogen, COO
R⁶, -O- (CH ₂)_f-COOR⁶, -O- (CH₂C
H (R⁷) O)_g-R⁶, -R⁸-COOR⁶, -R⁸-CO
NHR⁶, -NHCOR⁹(R⁶Is a hydrogen atom, alkyl
Group, substituted alkyl group, aryl group, and substituted aryl group
You. R⁷Is a hydrogen atom or a methyl group, R⁸Is an archille
Group, R⁹Represents an alkyl group, a substituted alkyl group,
Represents a silyl group, an aryl group or a substituted aryl group. f and g are
Represents an integer of 1 to 10. ). c is an integer from 0 to 2
Represents X represents a halogen. d and e are integers from 0 to 3
It represents a number, but is in the range of d + e ≦ 5. Specifically, 2,4-bis (trichloromethyl) -6-
(P-methoxystyryl) -s-triazine, 2,4-
Bis (trichloromethyl) -6- (p-methylstyrene
L) -s-triazine, 2,4-bis (trichloromethyl
) -6- (o, p-dimethylstyryl) -s-tria
Gin, 2,4-bis (trichloromethyl) -6- (o,
(p-dimethoxystyryl) -s-triazine and the like.
be able to.

The amount of the photopolymerization initiator used is usually 0.5 to 30% by weight, more preferably 2% by weight, based on the total solid content of the photosensitive layer.
~ 10% by weight.

Next, the co-condensed diazo resin will be described.

The co-condensed diazo resin used in the present invention includes, for example, a condensed resin of an aromatic diazonium compound and a carbonyl compound and salts of these condensed resins. These condensation resins have a carbonyl group in the molecule,
Those into which a group such as a sulfonyl group is introduced are preferred.

The co-condensed diazo resin preferably used in the present invention is an aromatic compound having a carbonyl group (eg, carboxyl group) or a sulfonyl group (eg, sulfonic acid group) and an aromatic diazonium compound, preferably diazodiphenylamine. It is a cocondensation compound having as a structural unit in the molecule.

The above-mentioned aromatic compound having a carbonyl group or a sulfonyl group contains an aromatic ring having at least one carbonyl group and / or an aromatic ring having at least one sulfonyl group in the molecule, In this case, the carbonyl group and the sulfonyl group may have the same aromatic ring.

The above aromatic ring is preferably an aryl group such as a phenyl group or a naphthyl group.

The above-mentioned carbonyl group and sulfonyl group may be directly bonded to the aromatic ring, or may be bonded via some bonding group (hereinafter, simply referred to as a joint).

In the above case, the number of carbonyl groups or sulfonyl groups bonded to one aromatic ring is preferably 1 or 2. Furthermore, as a joint, for example,
Examples thereof include an alkylene group having 1 to 4 carbon atoms.

Specific examples of the above-mentioned aromatic compound having a carbonyl group include benzoic acid, (o, m, p) -chlorobenzoic acid, phthalic acid, terephthalic acid, diphenylacetic acid,
Phenoxyacetic acid, p-methoxyphenylacetic acid, p-methoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,4-
Dimethylbenzoic acid, p-phenoxybenzoic acid, 4-anilinobenzoic acid, 4- (m-methoxyanilino) benzoic acid, 4- (p-methoxybenzoyl) benzoic acid, 4-
(P-methylanilino) benzoic acid, 4-phenylsulfonylbenzoic acid, salicylic acid, 4-methylsalicylic acid, 6
-Methylsalicylic acid, 4-ethylsalicylic acid, 6-propylsalicylic acid, 6-laurylsalicylic acid, 6-stearylsalicylic acid, 4,6-dimethylsalicylic acid, p-hydroxybenzoic acid, 2-methyl-4-hydroxybenzoic acid, 6-methyl -4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 2,6-dihydroxybenzoic acid, 2,6 -Dihydroxy-4-methylbenzoic acid, 4-chloro-2,6-dihydroxybenzoic acid, 4-methoxy-2,6-dioxybenzoic acid, gallic acid, phloroglucin carboxylic acid, 2,
4,5-trihydroxybenzoic acid, m-galloyl gallic acid, tannic acid, m-benzoyl gallic acid, m- (p-
Toluyl) gallic acid, protocatechu oil-gallic acid,
4,6-dihydroxyphthalic acid, (2,4-dihydroxyphenyl) acetic acid, (2,4-dihydroxyphenyl)
Acetic acid, (3,4,5-trihydroxyphenyl) acetic acid,
p-hydroxymethylbenzoic acid, p-hydroxyethylbenzoic acid, 4- (p-hydroxyphenyl) methylbenzoic acid, 4- (o-hydroxybenzoyl) benzoic acid, 4
-(2,4-dihydroxybenzoyl) benzoic acid, 4-
(P-hydroxyphenoxy) benzoic acid, 4- (p-hydroxyanilino) benzoic acid, bis (3-carboxy-
4-hydroxyphenyl) amine, 4- (p-hydroxyphenylsulfonyl) benzoic acid, 4- (p-hydroxyphenylthio) benzoic acid, and the like. Of these, salicylic acid, p-hydroxybenzoic acid, p-methoxybenzoic acid and metachlorobenzoic acid.

Further, specific examples of the aromatic compound having a sulfonyl group include benzenesulfonic acid, (o, m,
p) -chlorobenzenesulfonic acid, p-methoxybenzenesulfonic acid, 2,4-dimethoxybenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, p-phenoxybenzenesulfonic acid, 4-anilinobenzenesulfonic acid, 4- ( m-methoxyanilino) benzenesulfonic acid, 4- (p-methoxybenzoyl) benzenesulfonic acid, 4- (p-methylanilino) benzenesulfonic acid,
4-phenylsulfonylbenzenesulfonic acid, p-hydroxybenzenesulfonic acid, 2-methyl-4-hydroxybenzenesulfonic acid, 6-methyl-4-hydroxybenzenesulfonic acid, 2,6-dimethyl-4-hydroxybenzenesulfonic acid, 2,4-dihydroxybenzenesulfonic acid, 2,4-dihydroxy-6-methylbenzenesulfonic acid, 2,6-dihydroxybenzenesulfonic acid, 2,6-dihydroxy-4-methylbenzenesulfonic acid, 4-chloro-2, 6-dihydroxybenzenesulfonic acid, 4-methoxy-2,6-dioxybenzenesulfonic acid, 2,4,5-trihydroxybenzenesulfonic acid, p-hydroxymethylbenzenesulfonic acid, p-hydroxyethylbenzenesulfonic acid, 4- (P-hydroxyphenyl) meth Benzenesulfonic acid, 4-(o-
(Hydroxybenzoyl) benzenesulfonic acid, 4-
(2,4-dihydroxybenzoyl) benzenesulfonic acid, 4- (p-hydroxyphenoxy) benzenesulfonic acid, 4- (p-hydroxyanilino) benzenesulfonic acid, bis (3-carboxy-4-hydroxyphenyl) amine, Examples thereof include 4- (p-hydroxyphenylsulfonyl) benzenesulfonic acid and 4- (p-hydroxyphenylthio) benzenesulfonic acid, and particularly preferred are benzenesulfonic acid, p-hydroxybenzenesulfonic acid, and p-hydroxybenzenesulfonic acid. Methoxybenzenesulfonic acid and metachlorobenzenesulfonic acid.

The aromatic diazonium compound forming the constitutional unit of the above-mentioned co-condensed diazo resin is used as a salt, for example, a diazonium salt as described in JP-B-49-48001 can be used. Particularly, diphenylamine-4-diazonium salts are preferable.

The diphenylamine-4-diazonium salts are derived from 4-amino-diphenylamines, and such 4-amino-diphenylamines include 4-amino-diphenylamine and 4-amino-3-.
Methoxy-diphenylamine, 4-amino-2-methoxy-diphenylamine, 4-amino-2'-methoxy-
Diphenylamine, 4-amino-4'-methoxy-diphenylamine, 4-amino-3-methyldiphenylamine, 4-amino-3-ethoxy-diphenylamine, 4
-Amino-3-β-hydroxy-ethoxydiphenylamine, 4-amino-diphenylamine-2-sulfonic acid, 4-amino-diphenylamine-2-carboxylic acid,
4-amino-diphenylamine-2'-carboxylic acid and the like can be mentioned, and 4-amino-4'-methoxy-diphenylamine and 4-amino-diphenylamine are particularly preferable.

The above-mentioned co-condensed diazo resin can be obtained by a known method, for example, Photographic Science and Engineering (Photo.Sci.Eng.) Vol. 17, page 33 (197).
3), US Pat. Nos. 2,063,631 and 2,679,498, a diazonium salt, an aromatic compound having a carboxyl group and / or a hydroxyl group, and aldehydes in sulfuric acid, phosphoric acid or hydrochloric acid, For example, it can be obtained by polycondensing paraformaldehyde, acetaldehyde, benzaldehyde or ketones such as acetone and acetophenone.

The aromatic compound having a carbonyl group or sulfonyl group in the molecule, the aromatic diazo compound and the aldehydes or ketones may be freely combined with each other, and two or more kinds of them may be mixed and co-condensed. Although it is also possible, it is preferably a co-condensation resin of diazodiphenylamine and an aromatic compound having a carbonyl group or a sulfonyl group in the molecule, and more preferably diazodiphenylamine and benzoic acid, hydroxybenzoic acid or phenylacetic acid. Is a cocondensation product with a diazodiphenylamine and p-hydroxybenzoic acid.

The molar ratio of the aromatic compound having at least one of the carbonyl group and the sulfonyl group to the aromatic diazo compound is usually 1: 0.1 to 0.1: 1, preferably 1: 0.5 to 0.2: 1, more preferably 1: 1 to 0.2: 1
It is. Further, in this case, the molar ratio of the total amount of the aromatic compound and the aromatic diazo compound having at least one of a carbonyl group and a sulfonyl group to the aldehydes or ketones is usually 1: 0.6 to 1.5, preferably 1: 0.7 to 1.2
Then, the co-condensed diazo resin is obtained by reacting at low temperature for a short time, for example, for about 3 hours.

The counter anion of the co-condensed diazo resin used in the present invention includes an anion which forms a salt with the co-condensed diazo resin in a stable manner and makes the resin soluble in an organic solvent. These include organic carboxylic acids such as decanoic acid and benzoic acid, and organic phosphoric acids and sulfonic acids such as phenylphosphoric acid. Typical examples include methanesulfonic acid, chloroethanesulfonic acid, dodecanesulfonic acid, and benzenesulfonic acid. , Toluenesulfonic acid, mesitylenesulfonic acid, and anthraquinonesulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, hydroxysulfonic acid, 4-acetylbenzenesulfonic acid,
Aliphatic and aromatic sulfonic acids such as dimethyl-5-sulfoisophthalate, 2,2 ', 4,4'-tetrahydroxybenzophenone, 1,2,3-trihydroxybenzophenone, 2,2', 4-trihydroxy Hydroxyl-containing aromatic compounds such as benzophenone, halogenated Lewis acids such as hexafluorophosphoric acid and tetrafluoroboric acid, C
lO _4, IO ₄ perhalogen acids such as including but not limited to these. Among these, particularly preferred are hexafluorophosphoric acid, tetrafluoroboric acid, 2-hydroxy-4-methoxybenzophenone-5.
-Sulfonic acid.

The molecular weight of the above co-condensed diazo resin can be obtained as an arbitrary value by variously changing the molar ratio of each monomer and the condensation conditions, but it is effectively used for the intended purpose of the present invention. In order to have a molecular weight of about 400-10,000
It is generally selected from the range of, but preferably about 800 to 5,000.

The co-condensed diazo resin is preferably contained in the photopolymerizable composition in an amount of 1 to 12% by weight.

Next, an alkali-soluble or swellable binder polymer (hereinafter referred to as "the present invention") in which 50 mol% or more of the repeating units constituting the main chain used in the present invention are constituted of repeating units derived from a methacrylic acid derivative. This is referred to as a binder polymer).

The binder polymer of the present invention is not particularly limited as long as it is an alkali-soluble or swellable binder polymer in which 50 mol% or more of the repeating units constituting the main chain are constituted by repeating units derived from a methacrylic acid derivative. However, it is preferably a copolymer of vinyl monomers.

As the methacrylic acid derivative constituting the repeating unit of the binder polymer of the present invention, for example, the following monomers are preferably used. (1) methyl methacrylate, ethyl methacrylate,
(Substituted) alkyl methacrylates such as propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl acrylate, N-diethylaminoethyl methacrylate (2) Methacrylic acid, 2-hydroxyethyl methacrylate, 4-hydroxybutyl Methacrylic acid esters having aliphatic hydroxyl groups such as methacrylate, o, m, p
-Hydroxyphenylmethacrylamide, o, m, p-
Vinyl monomers having an aromatic hydroxyl group in the side chain such as hydroxyphenyl methacrylate Among the above methacrylic acid derivatives, preferred methacrylic acid derivatives for use in the present invention are methyl methacrylate, ethyl methacrylate, methacrylic acid, and 2-hydroxyethyl. Methacrylate, 4-hydroxybutyl methacrylate, o, m, p-hydroxyphenyl methacrylamide, o, m, p-hydroxyphenyl methacrylate.

Further, the binder polymer of the present invention preferably has a repeating unit from an addition polymerizable monomer having an aromatic hydroxyl group in the molecule.

The monomer used for introducing the repeating unit from the addition polymerizable monomer having an aromatic hydroxyl group into the molecule is not particularly limited as long as it is an addition polymerizable monomer having an aromatic hydroxyl group. A monomer represented by the following general formula (1) is preferable.

[0047]

[Chemical 6] [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents —COO
-, -CONH-. n represents 0 or 1. Examples of the other monomer constituting the binder polymer of the present invention include (a) acrylic acid esters having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate (b) α such as acrylic acid, maleic anhydride, and itaconic acid. , Β-unsaturated carboxylic acid (c) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid-
(Substituted) alkyl acrylates such as 2-chloroethyl, glycidyl acrylate and N-dimethylaminoethyl acrylate (d) acrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl acrylamide, N-cyclohexyl acrylamide, N-hydroxy Acrylamides such as ethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide (e) Ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether , Vinyl ethers such as phenyl vinyl ether (f) Vinyl acetate, vinyl chloroacetate, vinyl Vinyl esters such as stylate and vinyl benzoate (g) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene (h) Methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, etc. Vinyl ketones (i) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene (j) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine and the like.

The binder polymer of the present invention preferably uses the following monomers in order to obtain excellent alkali solubility. (1) α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, etc. (2) 2-hydroxyethyl (meth) acrylate, 4
Acrylic acid esters having an aliphatic hydroxyl group such as -hydroxybutyl (meth) acrylate, methacrylic acid esters (3) o, m, p-hydroxyphenyl (meth) acrylamide, o, m, p-hydroxystyrene, o,
m, p-hydroxyphenyl (meth) acrylate;
Vinyl monomer having aromatic hydroxyl group in side chain such as o, m, p-hydroxyphenylmaleimide The binder polymer of the present invention can be obtained by polymerizing the above-mentioned monomer by a known means.

Further, these vinyl type copolymers may have an unsaturated bond capable of being cross-linked by light in the molecule for the purpose of improving the curability with respect to light. Examples of the group having such an unsaturated bond include an acryl group, a methacryl group, a maleimide group, a cinnamyl group, and a cinnamoyl group.

The molecular weight of the binder polymer of the present invention is
The weight average molecular weight is preferably 5,000 to 200,000, and more preferably 20,000 to 12,000.

The binder polymer of the present invention is preferably used so that the weight ratio of the compound having an addition-polymerizable unsaturated bond in the molecule / the binder polymer of the present invention is from 5/95 to 70/30. , 10/90 to 50/50 are preferably used.

The photosensitive composition of the present invention may further contain a dye. The dye is used for the purpose of obtaining a visible image by exposure (exposed visible image) and a visible image after development.

As the dye, those which change color tone by reacting with free radicals or acids can be preferably used.
Here, the term “color tone changes” includes both a change from colorless to a color tone and a change from color to colorless or a different color tone. Preferred dyes are those which form a salt with an acid to change the color tone.

Examples of dyes that change from colored to colorless or to different colored tones include Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) and Oil Blue #.
603 [manufactured by Orient Chemical Industry Co., Ltd.], patent pure blue [manufactured by Sumitomo Sangoku Chemical Co., Ltd.], crystal violet,
Brilliant Green, Ethyl Violet, Methyl Violet, Methyl Green, Erythrosin B, Basic Fuchsin, Malachite Green, Oil Red, m
-Cresol purple, rhodamine B, auramine, 4
Examples thereof include triphenylmethane dyes, diphenylmethane dyes, oxazine dyes, xanthene dyes, iminonaphthoquinone dyes, azomethine dyes, and anthraquinone dyes represented by -p-diethylaminophenyliminonaphthoquinone and cyano-p-diethylaminophenylacetanilide.

On the other hand, examples of dyes that change from colorless to colored include, for example, leuco dyes and triphenylamine, diphenylamine, o-chloroaniline,
1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis-dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p ', p "-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p ', p "-triamino-o-
Methyltriphenylmethane, p, p'-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane, p,
Examples thereof include primary or secondary arylamine dyes represented by p ′, p ″ -triaminotriphenylmethane.

Among these dyes, triphenylmethane type dyes and diphenylmethane type dyes are preferable, triphenylmethane type dyes are more preferable, and Victoria Pure Blue BOH is particularly preferable.

The above dye is usually contained in the solid content of the photosensitive composition in an amount of 0.5 to 10% by weight, preferably about 1 to 5% by weight.

Various additives can be further added to the photosensitive composition of the present invention.

For example, alkyl ethers (eg, ethyl cellulose, methyl cellulose) for improving coating properties, fluorochemical surfactants, and nonionic surfactants (eg, Pluronic L-64 (Asahi Denka Co., Ltd.)
Plasticizer (for example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
Tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers and polymers of acrylic acid or methacrylic acid), and a sensitizing agent for improving the lipophilicity of an image area (for example, JP-A-55 / 55) No. 527, a half-esterified product of a styrene-maleic anhydride copolymer with an alcohol), a stabilizer [for example, phosphoric acid, phosphorous acid, organic acids (citric acid, oxalic acid, benzenesulfonic acid, naphthalene sulfone) acid,
4-methoxy-2-hydroxybenzophenone-5-sulfonic acid, tartaric acid, etc.)] and development accelerators (eg, higher alcohols, acid anhydrides, etc.). The amount of these additives varies depending on the purpose of use, but is generally 0.01 to 30% by weight based on the total solid content of the photosensitive layer.

The photosensitive lithographic printing plate of the present invention is prepared by using the photosensitive composition of the present invention in a suitable solvent (for example, methyl cellosolve,
Ethyl cellosolve, methyl cellosolve acetate, acetone, methyl ethyl ketone, methanol, dimethylformamide, dimethylsulfoxide, methyl lactate, 4-hydroxy-2-butanone, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, water or a mixture thereof Etc.) to prepare a coating solution of the photosensitive composition, apply the solution on a support, and dry to form a photosensitive layer.

As the solvent, it is preferable to use lactic acid ester such as methyl lactate. Lactic acid esters such as methyl lactate are preferred because they are excellent in environmental suitability, have no problem in safety, have a suitable boiling point and are easy to dry.

The concentration of the photosensitive composition in the coating liquid is 1 to
It is desirable to set it in the range of 50% by weight.

For coating, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and curtain coating can be used.

In this case, the coating amount may be about 0.2 to 10 g / m ² in dry weight.

As the support, paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) laminated paper, aluminum (including aluminum alloy), metal plate such as zinc, copper, cellulose diacetate, cellulose triacetate, etc. , Plastic films such as cellulose propionate, polyethylene terephthalate, polyethylene, polypropylene, and polycarbonate polyvinyl acetal, paper or plastic films laminated or vapor-deposited with the above metals, steel plates plated with aluminum or chrome. Of these, aluminum and aluminum-coated composite supports are particularly preferred.

Further, it is desirable that the surface of the aluminum material is roughened for the purpose of enhancing water retention and improving adhesion to the photosensitive layer.

Examples of the surface roughening method include generally known brush polishing method, ball polishing method, electrolytic etching, chemical etching, liquid honing, sand blasting and the like and combinations thereof, preferably brush polishing method,
Examples include electrolytic etching, chemical etching, and liquid honing, of which a surface roughening method including the use of electrolytic etching is particularly preferable. Further, as an electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used, and among these, an electrolytic solution containing hydrochloric acid, nitric acid or a salt thereof is used. Liquids are preferred. Further, the roughened aluminum plate is desmutted with an acid or alkali aqueous solution as required. The aluminum plate thus obtained is desirably subjected to anodic oxidation treatment, and particularly preferably a method of treating the aluminum plate with a bath containing sulfuric acid or phosphoric acid. Further, if necessary, surface treatment such as treatment with an alkali silicate or hot water, or immersion in a water-soluble polymer compound or an aqueous solution of potassium fluorozirconate can be performed.

The binder polymer of the present invention has excellent compatibility with a compound having an addition polymerizable unsaturated bond in the molecule, and a compound having an addition polymerizable unsaturated bond in the molecule may be deposited on the surface of the photosensitive layer. Therefore, the photosensitive composition of the present invention can provide a photosensitive lithographic printing plate excellent in blocking property without providing a protective layer or the like. Further, as a result of the improved compatibility, the crosslinked structure of the exposed portion becomes denser and chemical resistance, particularly resistance to UV ink washing oil, can be improved.

The photosensitive composition of the present invention can provide a photosensitive lithographic printing plate excellent in blocking property without providing a protective layer or the like, but the photosensitive composition of the present invention can be produced by oxygen in the air. In the case of having a polymerization inhibiting action, in order to prevent the polymerization inhibiting action due to oxygen in the air, for example, polyvinyl alcohol, acidic celluloses, etc. are formed on the layer of the photosensitive composition provided on the support. A protective layer made of a polymer having an excellent oxygen barrier property may be provided.

The photosensitive lithographic printing plate of the present invention can be processed by a conventional method.

That is, by exposing through a transparent original image having a line image, a halftone image and the like, and then developing with an aqueous developer, a negative relief image is obtained with respect to the original image. Examples of the active light source suitable for exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a metal halide lamp, and a strobe.

The developing solution for the photosensitive lithographic printing plate of the present invention is not particularly limited, but particularly preferred is an alkaline aqueous solution containing substantially no organic solvent.

The term "substantially free of organic solvent" means that the organic solvent is not contained to the extent that it causes problems in hygiene and safety, and that it does not contain any organic solvent. is not. Generally, when the organic solvent contained in the developer composition is 1% by weight or less, these problems do not occur.

From the viewpoint of hygiene and safety, the content of the organic solvent contained in the developer composition is preferably small, and the content of the organic solvent is 0.5% by weight or less, more preferably the content of the organic solvent. It is not to contain at all.

Preferred alkaline agents used in the developer include potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, and dibasic sodium phosphate. Examples thereof include potassium triphosphate, dibasic potassium phosphate, sodium carbonate, potassium carbonate and the like. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, or sodium silicate has the best development gradation and is most preferable.

In the present invention, the composition of alkali silicate is [SiO ₂ ] / [M] = 0.5 to 1.5 (where [S
i0 ₂ ] and [M] represent the molar concentration of SiO ₂ and the total alkaline metal concentration, respectively. ) And SiO ₂
A developer containing 0.8 to 8% by weight is preferably used.

Further, the composition of alkali silicate is [SiO ₂ ] / [M] = 0.5 to 0.75 in molar ratio, and SiO ₂
A developer in which ₂ is 0.8 to 4% by weight is preferable in that the waste developer is easily neutralized due to its low concentration.
i0 ₂ ] / [M] = 0.75 to 1.3, and SiO ₂ is 1 to 8
A developer having a weight percent is preferable because it has a high buffering power and a high processing capacity.

The pH (25 ° C.) of the developing solution is preferably 12 or more, more preferably 12.5 to 14. Further, water-soluble sulfites such as sodium sulfite, potassium sulfite, lithium sulfite, and magnesium sulfite can be added to the developer. The preferred content of sulfite in the developer composition is 0.05 to 4% by weight.
And more preferably 0.1 to 1% by weight.

In the developer, anionic surfactants and amphoteric surfactants as described in JP-A-50-51324, JP-A-59-75255 and JP-A-60-111246 are also included. By incorporating at least one of the nonionic surfactants as described in JP-A No.
By incorporating a polymer electrolyte as described in JP-A-95946 and JP-A-56-142528, the wettability to the photosensitive layer can be enhanced and the gradation can be further enhanced. The amount of the surfactant added is not particularly limited, but is preferably 0.003 to 3% by weight, and particularly 0.006 to 1% by weight.
Is preferred.

Further, it is preferable to use an alkali silicate containing 20 mol% or more of all alkali metals in the developer because the generation of insoluble matter in the developer is reduced, and more preferably 90 mol% or more of potassium is used. That is the most preferable case is 100 mol% of potassium.

Further, the developer used in the present invention may contain an antifoaming agent. Suitable defoamers include organosilane compounds.

[0082]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Example << Preparation of sand grain >> An aluminum plate having a thickness of 0.3 mm is electrolytically surface-roughened in an aqueous hydrochloric acid solution, then anodized in an aqueous hydrochloric acid solution, and hydrophilized using an aqueous sodium silicate solution. An aluminum support was obtained. << Preparation of Photosensitive Planographic Printing Plate Samples 1 to 10 >> A photosensitive composition coating liquid having the composition shown below was applied to the obtained support using a wire bar and dried to obtain a photosensitive lithographic printing plate sample 1 Got 10. At this time, the coating amount of the photosensitive composition coating liquid was set to be 1.5 mg / m ² as a dry weight.

<Photosensitive composition coating liquid composition> Samples 1 to 4 Acrylic polymer compound (described in Table 1) 5.0 g Glycerol dimethacrylate 5.0 g 2,4-Diethylthioxanthone 0.5 g p-Dimethylaminobenzoic acid ethyl ester 0.5g Co-condensation product of p-diazodiphenylamine PF6 salt and p-hydroxybenzoic acid (molar ratio 60/40, Mw.2,500) 1.0g Julimer AC10L (40% by weight polyacrylic acid aqueous solution, manufactured by Nippon Pure Chemical Co., Ltd.) 0.5g Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.1g Methyl lactate 180g 1-Ethoxypropanol 20g

Samples 5 and 6 Acrylic polymer compound (described in Table 1) 6.0 g Glycerol dimethacrylate 4.0 g 2,4-Diethylthioxanthone 0.5 g p-Dimethylaminobenzoic acid ethyl ester 0.5 g p-diazodiphenylamine PF6 salt Co-condensate with p-hydroxybenzoic acid (molar ratio 60/40, Mw.3,000) 0.5 g Julimer AC10L (40 wt% polyacrylic acid aqueous solution, manufactured by Nippon Pure Chemical Co., Ltd.) 0.5 g Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) Co., Ltd.) 0.1 g Methyl lactate 180 g 1-Ethoxypropanol 20 g

Samples 7 to 10 Acrylic polymer compound (described in Table 1) 6.0 g Glycerol dimethacrylate 4.0 g 2,4-Diethylthioxanthone 0.2 g p-diazodiphenylamine PF6 salt and p-hydroxybenzoic acid co-condensate (Mole ratio 60/40, Mw.2,500) 0.5 g Julimer AC10L (40 wt% polyacrylic acid aqueous solution, manufactured by Nippon Pure Chemical Co., Ltd.) 0.5 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.1 g Methyl lactate 180 g 1-Ethoxypropanol 20g

[0086]

[Table 1]

The acrylic polymer compounds 1 to 10 used in the photosensitive composition coating liquid are synthesized as follows. (Synthesis of Acrylic Polymer Compound 1) A 500 ml 4-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet tube was charged with a mixed solvent of 85 ml of acetone and 85 ml of methanol, and ethyl acetate. Acrylate 25.0 g (0.25 mol), ethyl methacrylate 33.1
g (0.29 mol), acrylonitrile 12.7 g (0.24 mol), methacrylic acid 3.3 g (0.0385 mol, 55% of total methacrylic acid) and 4-hydroxyphenylmethacrylamide 14.6 g (0.0825 mol, total 4-hydroxyphenylmethacrylamide) 55%) was dissolved. Further, 3.28 g (0.02 mol) of azobisisobutyronitrile as a polymerization initiator was dissolved and refluxed with stirring under a nitrogen stream.

1.5 hours after the start of reflux, 1.8 g of methacrylic acid
(0.021 mol, 30% of total methacrylic acid), 4-hydroxyphenylmethacrylamide 8.0 g (0.045 mol, total 4-
A solution prepared by dissolving 30% of hydroxyphenylmethacrylamide) in a mixed solvent of 10 ml of acetone and 10 ml of methanol was added dropwise to the reaction solution over 10 minutes.
Methacrylic acid 0.9 g (0.0
105 mol, 15% of total methacrylic acid), 4.0 g of 4-hydroxyphenylmethacrylamide (0.0225 mol, 15% of total 4-hydroxyphenylmethacrylamide) dissolved in a mixed solvent of 5 ml of acetone and 5 ml of methanol. , Was added dropwise to the reaction solution over 10 minutes.

After refluxing for 3 hours, the reaction solution was cooled to room temperature and poured into water to precipitate a polymer compound. This was collected by filtration and vacuum dried at 50 ° C. for 24 hours to obtain an acrylic polymer compound 1.

The acrylic polymer compound 1 thus obtained had an average molecular weight of 75,000 as measured by gel permeation chromatography (GPC) with pullulan standard and N, N-dimethylformamide (DMF) solvent. .

(Synthesis of acrylic polymer compounds 2 to 6)
Acrylic polymer compounds 2 to 6 were synthesized under the same synthetic conditions as in the synthesis of acrylic polymer compound 1, except that the amounts of all monomers used were changed as shown in Table 2. However, at the initial stage of the reaction, all the monomers other than methacrylic acid and 4-hydroxyphenylmethacrylamide were charged. Further, methacrylic acid and 4-hydroxyphenylmethacrylamide are 55 mol% of total methacrylic acid and 4-hydroxyphenylmethacrylamide at the initial stage of the reaction, and 30 mol% of total methacrylic acid and 4-hydroxyphenylmethacrylamide are refluxed. 1.5 hours after the start, 15 mol% of all methacrylic acid and all 4-hydroxyphenylmethacrylamide were charged 3 hours after the start of reflux.

The average molecular weights of the obtained acrylic polymer compounds 2 to 6 were measured in the same manner as in the acrylic polymer compound 1. Table 2 shows the obtained results.

(Synthesis of Acrylic Polymer 7) 50 equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet tube
A mixed solvent of 100 ml of acetone and 100 ml of methanol was placed in a 0 ml four-necked flask, and ethyl acrylate 9.09 (0.09 mol), ethyl methacrylate 34.2 g (0.30 mol), acronitrile 15.9 g.
(0.30 mol), methacrylic acid 0.86 g (0.01 mol), and 4-hydroxyphenylmethacrylamide 51.6 g
(0.30 mol) was dissolved. Furthermore, 3.28 g (0.02 mol) of azobisisobutyronitrile was dissolved as a polymerization initiator,
The mixture was heated under a nitrogen stream with stirring and refluxed for 6 hours.

After completion of the reaction, the reaction solution was cooled to room temperature and poured into water to precipitate the polymer compound. I collected this by filtration,
Acrylic polymer compound 7 after vacuum drying at 50 ℃ for 24 hours
I got

The average molecular weight was 35,000 as measured by the same method as for the acrylic polymer compound 1.

(Synthesis of Acrylic Polymer 8-10) Acrylic polymer under the same synthetic conditions as the synthesis of Acrylic Polymer 7 except that the amounts of all monomers used were changed as shown in Table 2. Compounds 8-10 were synthesized.

By the same method as for the acrylic polymer compound 1, the average molecular weights of the obtained acrylic polymer compounds 8 to 10 were measured. Table 2 shows the obtained results.

Table 2 shows the proportion of the methacrylic acid derivative in the acrylic polymer compounds 1 to 10.

[0099]

[Table 2] With respect to the obtained photosensitive lithographic printing plate samples 1 to 10, UV washing oil resistance, blocking resistance, fatigue developing solution development suitability and fatigue developing solution precipitate amount were evaluated as follows. Table 3 shows the obtained results.

<< Evaluation of UV Washing Oil Resistance >> A photosensitive lithographic printing plate sample was used at 8 mW / using a 2 kw metal halide lamp.
After exposing at cm ² for 30 seconds, develop with the following developing solution (30
℃, 30 seconds).

The developed sample was immersed in UV wash oil (3-methoxy-3-methyl-1-butanol) for 5 minutes. The color densities of the sample before immersion and the sample after immersion were measured with a Sakura densitometer using a RED filter.
In addition, the color density of the sand was measured in the same manner, and the residual ratio (%) of the photosensitive layer was determined by the following to evaluate the UV washing oil resistance.

[0102]

[Equation 1]

<Developer composition> A potassium silicate (manufactured by Nippon Kagaku) 1160 g caustic potash: 133 g pure water: 5133 g (pH≈12.7)

<< Evaluation of Blocking Resistance >> A photosensitive lithographic printing plate sample was superposed on the surface of the photosensitive layer with interleaving paper, and 40 kg /
After applying a load of m ² and storing at 55 ° C. for 3 days, the presence or absence of blocking of the sample was visually observed, and the blocking resistance was evaluated according to the following evaluation criteria. <Evaluation criteria> ○: No blocking △: Slight blocking ×: Blocking

<< Evaluation of Fatigue Developer Development Suitability >> A photosensitive lithographic printing plate was overlaid with an Eastman Kodak step tablet and a negative image film original, and exposed at 8 mW / cm ² for 30 seconds using a 2 kw metal halide lamp. .

The exposed sample was developed (30 ° C., at 30 ° C.) with a developer (development fatigue solution) obtained by treating a photosensitive lithographic printing plate sample having a final exposure of 5 m ² with 1 liter of the above composition.
For 30 seconds), the obtained lithographic printing plate sample was used for printing with a Heidelberg GTO printing machine, and the degree of stain on the printing paper surface was visually observed, and the developability was evaluated according to the following evaluation criteria. <Evaluation Criteria> ○: No stain on the printing paper surface △: Slight stain on the printing paper surface △ ×: Staining on the printing paper surface ×: Many stains on the printing paper surface

<< Evaluation of Fatigue Developer Precipitation Amount >> A photosensitive lithographic printing plate sample after 5 m ² of end-exposure was treated with 1 liter of the developer having the above composition, and the precipitate produced in the developer was collected by filtration and dried. Then, the amount of the obtained precipitate was measured to evaluate the amount of precipitation of the fatigue developer.

[0108]

[Table 3]

[0109]

INDUSTRIAL APPLICABILITY The photosensitive composition and the photosensitive lithographic printing plate of the present invention are excellent in blocking resistance, chemical resistance, particularly resistance to UV ink washing oil, and are hand-woven, and substantially free of organic solvent. Excellent developability can be obtained even by the development with an alkaline aqueous solution, moreover, it is difficult to generate insoluble components in the developing solution, and a large amount of developing treatment can be carried out with a fixed amount of the developing solution.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Matsumura No. 1 Sakuramachi, Hino City, Tokyo Konica Stock Company

Claims (9)

[Claims] 1. A compound comprising (A) a compound having an addition-polymerizable unsaturated bond in the molecule, (B) a photopolymerization initiator, (C) a co-condensed diazo resin, and (D) an alkali-soluble or swellable binder polymer. In the photosensitive composition, the (D) alkali-soluble or swellable binder polymer is a repeating unit of 50 units of the main chain of the binder polymer.
A photosensitive composition, characterized in that a mol% or more is a binder polymer composed of repeating units derived from a methacrylic acid derivative. 2. The photosensitive composition according to claim 1, wherein the methacrylic acid derivative is an alkyl ester of methacrylic acid. 3. The alkali-soluble or swellable binder polymer (D) is a binder polymer having a repeating unit derived from an addition polymerizable monomer having an aromatic hydroxyl group, according to claim 1 or 2. Photosensitive composition. 4. The photosensitive composition according to claim 3, wherein the addition-polymerizable monomer having an aromatic hydroxyl group is a compound represented by the following general formula (1). Embedded image [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents —COO
-, -CONH-. n represents 0 or 1. ] 5. The (C) co-condensed diazo resin is a co-condensed product of diazodiphenylamine and an aromatic compound having at least one group selected from a carbonyl group and a sulfonyl group in the molecule. The photosensitive composition according to claim 1. 6. The photosensitive composition according to claim 1, wherein the co-condensed diazo resin (C) is a co-condensed product of diazodiphenylamine and p-hydroxybenzoic acid. 7. The method according to claim 1 on a hydrophilic support.
A photosensitive lithographic printing plate comprising a layer of the photosensitive composition according to item 6. 8. The photosensitive lithographic printing plate according to claim 7, wherein a protective layer is not provided on the layer of the photosensitive composition. 9. A plate-making method for a photosensitive lithographic printing plate, which comprises developing the photosensitive lithographic printing plate according to claim 8 with an alkaline aqueous solution having a pH of 12 or more substantially containing no organic solvent.