JPS63311247A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain high resistance to treating chemicals, particularly to a plate cleaner or cleaning liquid to be used in UV ink printing, and to obtain superior visible picture quality for exposed light by using a specified photosensitive compsn. CONSTITUTION:A quinonediazide compd., a compd. which generates a free radical by the irradiation with active rays, and a vinyl copolymer are contained in a photosensitive compsn. Said quinonediazide compd. to be used suitably is an ester of ortho quinonediazide sulfonic acid with a compd. having phenolic OH group. Suitable compd. which generates a free radical by the irradiation with active rays is pref. a trihaloalkyl compd. or a diazonium salt compd. Preferred vinyl copolymer is that having a structure unit contg. a phenolic OH group in the molecule. By this constitution, a photosensitive compsn. having improved visible picture quality for exposed rays and improved resistance to treating chemicals and being suitable for photosensitive lithographic printing form is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photosensitive composition suitable for positive-working photosensitive lithographic printing plates. The present invention relates to a photosensitive composition suitable for a positive-working photosensitive lithographic printing plate having excellent development tolerance.

(Background of the Invention) A positive-working photosensitive lithographic printing plate generally has an ink-receptive photosensitive layer formed on a hydrophilic support, which becomes solubilized by exposure to ultraviolet rays or the like. When this photosensitive layer is imagewise exposed and developed, the non-image area is removed leaving the image area, and an image is formed. In planographic printing, the difference in properties is utilized in that the image area is lipophilic and the non-image area is hydrophilic.

When performing so-called "multi-sided printing" in which multiple film originals are printed one after another on a photosensitive lithographic printing plate, the exposed and unexposed areas are It is necessary to be able to distinguish between For this reason, photosensitive compositions used in photosensitive lithographic printing plates generally include a printout material for forming a visible image upon exposure to light. The printout material consists of a compound that generates acids or free radicals when exposed to light, and a dye that changes color tone by interacting with this compound. Conventionally, compounds that generate acids or free radicals when exposed to light are , for example, JP-A-5
0-36209, 0-naphthoquinone diazide-4
- Sulfonic acid halogenides are described, which are
It has the disadvantage of poor storage stability. Also, JP-A-53-36
Trihalomethyl-2-pyrone and trihalomethyltriazine described in Publication No. 223, JP-A-55-77
Compounds that generate free radicals upon exposure to light, such as the halomethyl-vinyl-oxadiazole compound described in Publication No. 742, have good storage stability and the visible image quality upon exposure improves in proportion to the amount added. If the amount added is increased, it has the disadvantage of lowering sensitivity, lowering alkali solubility, and deteriorating developability.

On the other hand, the above-mentioned positive photosensitive lithographic printing plates have low resistance to various processing chemicals used during printing, such as isopropyl alcohol contained in fountain solution, ink, surface preparation liquid, plate cleaner, etc. As a result, there is a drawback that printing durability is reduced. Tokuko Showa 43-2840
Publication No. 3 describes that processing chemical resistance was improved by using O-naphthoquinonediazide sulfonic acid ester of a polycondensation resin of pyrogallol and acetone as a photosensitive component. This is normal oil-based ink.

It has shown some good performance against the processing chemicals used in printing with. However, in recent years, UV-curable U■
Printing using ink is increasing, and for the ink and processing chemicals (washing oil, plate cleaners, etc.) used for this U■ ink printing, the photosensitive components mentioned above are
When a normal novolac resin such as m-cresol novolak resin is used as a binder, it has a drawback of insufficient durability. Also, special public service in 1982-
Publication No. 54621 describes that a photosensitive composition containing as a binder a resin obtained by copolycondensing phenol, m- and p-mixed cresol, and aldehyde improves processing chemical resistance. However, the resin also has U■
They have very poor resistance to the processing chemicals used in ink printing.

Furthermore, Japanese Patent Publication No. 52-28401 describes a photosensitive composition containing as a binder a polymer containing p-hydroxymethacrylanilide or the like as a repeating structural unit, and Japanese Patent Publication No. 58-122533 The publication describes a photosensitive composition containing an acrylic copolymer as a binder. Although the processing chemical resistance has been improved by using these photosensitive compositions, the above-mentioned exposure and visible image properties are poor, and photosensitive compositions suitable for photosensitive lithographic printing plates with excellent overall performance are still not in practical use. It had not been standardized.

(Objective of the invention) The object of the present invention is to
The object of the present invention is to provide a photosensitive composition suitable for a photosensitive lithographic printing plate, which has improved exposure visibility and processing chemical resistance.

(Structure of the Invention) The above object of the present invention can be obtained by applying a photosensitive composition having the following structure to a photosensitive lithographic printing plate. That is, the photosensitive composition of the present invention is characterized by containing (a) a quinonediazide compound, (b) a compound that generates free radicals upon irradiation with actinic rays, and (c) a vinyl copolymer.

(Specific structure of the invention) The photosensitive composition of the present invention will be described in more detail below.

The quinonediazide compound used in the present invention is an ester compound of orthoquinonediazide sulfonic acid and a compound having a phenolic hydroxyl group.

Examples of the compound having a phenolic hydroxyl group include monomers such as -valent, divalent, and trivalent phenols, naphthols, and hydroxybenzophenes, and polycondensation resins of phenols and aldehydes or ketones. this house,
Phenolic water W! A compound having two or more iM is preferred, and a compound having three hydroxyl groups is particularly preferred.

The polycondensation resin is preferably one in which phenols and aldehydes or ketones are condensed, particularly in the presence of an acidic catalyst. Examples of the phenols include phenol, 0-cresol, ■-cresol, p-cresol, 3.5-xylenol, carvacrol, thymol, and p-alkyl group (1 to 8 carbon atoms)! ! Examples include monohydric phenols such as phenol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Among these, preferred are:
Among the divalent and trivalent polyhydric phenols, pyrogallol is more preferred. Examples of the aldehyde include formaldehyde, penzaldehyde, acetaldehyde, crotonaldehyde, and furfural. Among these, formaldehyde and benzaldehyde are preferred. Furthermore, examples of the ketone include acetone, methyl ethyl ketone, etc., with acetone being preferred.

When synthesizing the polycondensation resin, inorganic acids and organic acids such as hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, and phosphorus oxychloride are used as acidic catalysts, and the blending ratio of phenols and aldehydes or ketones is as follows: The aldehyde or ketone is used in an amount of 0.7 to 1.0 mole part per mole part of the phenol. However, when aldehyde or ketone is used as the reaction solvent, the mixing ratio is not limited to the above. Examples of reaction solvents used include alcohols such as methanol and ethanol, acetone, water, and tetrahydrofuran.

After reaction at a predetermined temperature (-5 to 120° C.) for a predetermined time (3 to 48 hours), the reaction product is obtained by heating under reduced pressure, washing with water and dehydration, or by precipitating water.

Specific examples of the polycondensation resin include phenol/formaldehyde resin, ■-cresol/formaldehyde resin, -1,p-mixed cresol/formaldehyde resin, phenol/cresol/formaldehyde resin, phenol/benzaldehyde resin, and cresol/benzaldehyde. resin, resorcinol-benzaldehyde resin, resorcinol-formaldehyde resin, pyrogallol-formaldehyde resin, pyrogallol-acetone resin, pyrogallol-benzaldehyde resin, hydroquinone-formaldehyde resin, catechol-formaldehyde resin and the like. Among these, preferred are:
They are pyrogallol formaldehyde resin, resorcinol, benzaldehyde resin and pyrogallol acetone resin. Most preferred is pyrogallol acetone resin.

The molecular weight (polystyrene standard) of the polycondensation resin is such that the weight average molecular weight MW is 5. OX 1Q 2~7.0×103
and the number average molecular weight Mn is 4.0×102 to 3.5×10
MW is preferably in the range of 3. More preferably, the MW is in the range of 7. O
x 102 to 2.5x 103, and Mn is 9. OX1
It is in the range of 02 to 2.0XIQ3.

The molecular weight of the resin is measured by GPC (gel permeation chromatography).

Calculation of number average molecular weight Mn and weight average molecular weight MW is based on Morio Tsuge, Tatsuya Miyabayashi, Masayuki Tanaka, “Journal of the Chemical Society of Japan” 8G
It shall be carried out by the method described on pages G to 805 (1972), by leveling the peaks of the oligomer region (connecting the centers of the peaks and valleys).

The quinonediazide compound of the present invention can be prepared by dissolving the phenol in a suitable solvent, such as dioxane, and adding 0-quinonediazide sulfonic acid chloride thereto.
It is obtained by esterification by dropping alkali carbonate to the equivalence point while stirring with heating.

In the ester compound, the condensation rate of 0-naphthoquinonediazide sulfonic acid chloride with respect to OHM of phenol (reaction rate % with respect to 11 OH) is 15 to 8.
It is preferably 0%, more preferably 20-50%, even more preferably 20-45%. The condensation rate is calculated by determining the content of sulfur atoms in the sulfonyl group by elemental analysis.

The amount of the quinonediazide compound in the photosensitive composition of the present invention is preferably 5 to 601% by weight, particularly preferably 10% by weight.
~50% by weight.

As the compound that generates a free M group upon irradiation with actinic rays used in the present invention, trihaloalkyl compounds or diazonium salt compounds represented by the following general formulas [I] and [[], respectively, are preferably used.

General formula [I] Mu (wherein xa represents a trihaloalkyl group having 1 to 3 carbon atoms, W represents N, S, Se, P, Z represents O, N%
S%Se, P is shown. Y has a chromophore group, and W and 2
Indicates a group consisting of a group of nonmetallic atoms necessary to cyclize.

) General formula [II] + Ar -N2 As a compound, the following general formula [1[[], [IV] or [
V].

General formula [1 [[] General formula [V] represents, n is ○,
1 or 2. 2-trichloromethyl-5-(p- methoxystyryl)-1,3,4-oxadiazole compounds and the like.

Further, as a specific example of the compound represented by the general formula [rV] or [L], 4-(2,4-dimethoxy-4-styryl) described in JP-A-53-36223 is
-6-Dolichloromethyl-2-pyrone compound, 2.4-
Bis-(trichloromethyl)-6-p-methoxystyryl-8-triazine compound, 2,4-bis-(trichloromethyl)-〇-〇-dimethylaminostyryl-8-
Examples include triazine compounds.

On the other hand, the diazonium salt compound is preferably a diazonium salt that generates a strong Lewis acid upon exposure to light, and a counter ion of an inorganic compound is recommended as the counter ion part. Specific examples include aromatic diazonium salts in which the anion moiety of the diazonium salt is at least one of a fluoride ion, an arsenic fluoride ion, an antimony fluoride ion, an antimony chloride ion, a tin chloride ion, a bismuth chloride ion, and a zinc chloride ion. Preferably, it is a diazophenylamine salt.

The content of the compound that generates free radicals upon irradiation with actinic rays in the total photosensitive layer composition is 0.01 to 20% by weight;
Preferably 0.1 to 20% by weight, more preferably 0.2
~10% by weight.

Furthermore, the vinyl copolymer used in the present invention is preferably a vinyl copolymer having a structural unit having a phenolic hydroxyl group in its molecular structure; It refers to a polymer formed by polymerization, and copolymers containing at least one structural unit of the following general formulas [VI] to [X] are more preferable.

General formula [VI] +CR+ R2-CRa← 0-Co-B-OH General formula [■] General formula [■] -(-CR+ R2-CRa→- COO+AkB -OH General formula [rX] 1+CR1R2-CR3← - 0H General formula [X] OH In the formula, R1 and R2 each represent a hydrogen atom, an alkyl group, or a carboxyl group, preferably a hydrogen atom. R3 represents a hydrogen atom, a halogen atom, or an alkyl group, preferably a hydrogen atom. an atom or an alkyl group such as a methyl group or an ethyl group.R+ is a hydrogen atom, an alkyl group,
It represents an aryl group or an aralkyl group, preferably an aryl group. A represents an alkylene group that may have a substituent that connects a nitrogen atom or an oxygen atom and an aromatic carbon atom, - represents an integer from 0 to 10, and B represents a phenylene group that may have a substituent. Represents a naphthylene group which may have a group or a substituent. Among these, copolymers containing at least one structural unit represented by the general formula [■] are preferred.

In the copolymer of the present invention, the general formulas [VI] to [X
] Examples of monomer units that can be used in combination with the structural unit shown are ethylene, propylene,
Ethylenically unsaturated olefins such as isobutylene, butadiene, isoprene, etc., styrenes such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, etc., acrylic acids such as acrylic acid, methacrylic acid, etc., e.g. itaconic acid , unsaturated aliphatic dicarboxylic acids such as maleic acid and maleic anhydride, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α - Esters of α-methylene aliphatic monocarboxylic acids such as methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, ethyl ethacrylate, nitriles such as acrylonitrile, methacrylonitrile, amides such as acrylamide, e.g. acrylic Anilide, p-chloroacrylanilide, Sono-nitroacrylanilide, -
Anilides such as monomethoxyacrylanilide, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl acetate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, β-chloroO ethyl vinyl ether, Vinyl chloride, vinylidene chloride, vinylidene cyanide, such as 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1
- Ethylene derivatives such as methyl-1-nitroethylene,
For example, N-vinylpyrol, N-vinylcarbazole,
There are vinyl monomers such as N-vinyl compounds such as N-vinylindole, N-vinylpyrrolidone, and N-vinylpyrrolidone. These vinyl monomers exist in polymer compounds with a structure in which unsaturated double bonds are cleaved.

Among the above monomers, (meth)acrylic acids, esters of aliphatic monocarboxylic acids, and nitriles exhibit excellent overall performance and are therefore preferred. More preferred are methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate, and the like.

These monomers may be bound in the copolymer of the present invention in either a block or random manner.

The above vinyl copolymers may be used alone in the photosensitive composition of the present invention, or two or more of them may be used in combination. Moreover, it may be used together with other polymer compounds.

The proportion of the vinyl copolymer of the present invention in the photosensitive composition is preferably 50 to 95% by weight, more preferably 60% by weight.
~90% by weight.

Typical examples of the vinyl copolymer of the present invention are listed below, but the vinyl copolymer of the present invention is not limited to the following compounds.

In the following example compounds, MW is 1ffi average molecular weight, Mn is number average molecular weight, s, and 1. o, I and n each represent the mol% of the structural unit (Mw=280
00. Mw/Mn=7.8 m:n=40:60) (
Mw=22000. Mw/Mn=6.9 m:n
:l = 30:40:30) (Mw = 33000
．． Mw/41V4n = 31 m: n:
l=20:35:45)(r41 (Mw=33000. Mw/Mn=7 m:
n: l = 38:60:2)
Button S 6 Sat CH.

Exposure (MW=2oooo, Mw/Mn=2.1m:
n:j:o;3o:3o:36. r:3. S) The photosensitive composition of the present invention preferably contains an organic dye that changes its color tone by interacting with a compound that generates free radicals upon irradiation with actinic rays.

Examples of such organic dyes include Victoria Pure Blue BOH [Hodogaya Chemical] and Oil Blue #6.
03 [Orient Chemical], Patent Pure Blue [manufactured by Sumitomo Mikuni Chemical], Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Green, Erythrosin B1 Basic Tsuksin, Malachite Green, Oil Red, -1 Cresol Purple B1 Auramine, 4-p - Triphenylmethane type represented by diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenylacetanilide, etc.
Examples include diphenylmethane-based, oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based, and anthraquinone-based dyes. Among these, triphenylmethane dyes are preferred.

Further, it is preferable that the photosensitive composition of the present invention further contains an organic acid such as dicarboxylic acids, and examples of such dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, Examples include pimelic acid, maleic acid, nicotinic acid, phthalic acid, picric acid, fumaric acid, etc. Among these, pKat at 25°C
Those having ii of 3.0 or more are preferably used.

Further, a sensitizer for improving sensitivity can also be added to the photosensitive composition of the present invention. Examples of the sensitizer include gallic acid derivatives described in JP-A-57-118237, five-membered cyclic acid anhydrides as described in JP-A-52-80022, such as phthalic anhydride, Tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, birometic acid, itaconic acid, etc., and 6-membered cyclic acid anhydrides as described in JP-A-58-11932, for example, Examples include glutaric anhydride and derivatives thereof. Among these, cyclic acid anhydrides are preferred, and 6-membered cyclic acid anhydrides are particularly preferred.

The photosensitive composition of the present invention combines the above materials,
By containing, the purpose of the present invention can be achieved, but in addition to each of these materials, pigments such as dyes and pigments, plasticizers, surfactants, etc. may be added as necessary. Can be done.

A positive-working photosensitive lithographic printing plate can be formed by dissolving the photosensitive composition of the present invention in a solvent that dissolves each of the above-mentioned components, and applying and drying the solution on the surface of a suitable support. Examples of solvents that can be used include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, and methyl ethyl ketone. These solvents may be used alone or in combination of two or more.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating, etc. can be used.

Supports on which the photosensitive layer is provided using the photosensitive composition of the present invention include metal plates such as aluminum, zinc, copper, steel, etc., and metal plates plated or vapor-deposited with chromium, zinc, copper, nickel, aluminum, iron, etc. Examples include metal plates, paper, plastic films, paper coated with resin, paper covered with metal foil such as aluminum, and plastic films treated to make them hydrophilic. Among these, aluminum plates are preferred. When an aluminum plate is used as a support, it is preferably subjected to surface treatments such as graining, anodizing, and, if necessary, sealing. Known methods can be applied to these treatments.

Examples of the graining treatment include a mechanical method and an electrolytic etching method. Examples of mechanical methods include ball polishing, brush polishing, liquid honing, and puff polishing.

The various methods described above can be used alone or in combination depending on the composition of the aluminum material. Preferred is electrolytic etching.

Electrolytic etching is carried out in a bath containing one or a mixture of two or more inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid. After the graining process, desmutting is performed using an alkali or acid aqueous solution as necessary to neutralize the material, followed by washing with water.

For anodizing, the electrolyte used is sulfuric acid, chromic acid, oxalic acid, phosphoric acid, or manganese! Electrolysis is carried out using a solution containing one or more of the following, using an aluminum plate as an anode. The amount of anodic oxide film formed is 1 to 5011G/
di' is suitable, preferably 10 to 401 Mdf. The ml amount of anodized skin is, for example, an aluminum plate in a phosphoric acid chromic acid solution (85% phosphoric acid solution: 35 mff11
Chromium oxide (■): Prepared by dissolving 20o in 1ffi water) to dissolve the oxide film, and determine by measuring the weight change of the plate before and after the film is dissolved.

Specific examples of the sealing treatment include boiling water treatment, steam treatment, sodium silicate treatment, and dichromate aqueous solution treatment. In addition, the aluminum plate support may be subjected to subbing treatment using an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconate.

In addition, in general, when contact baking a film original onto a photosensitive lithographic printing plate, the printing frame is vacuumed, and a method for improving this vacuum adhesion is also a positive-working photosensitive lithographic printing plate using the photosensitive composition of the present invention. Can be applied to printing plates. Methods for improving vacuum adhesion include mechanically creating unevenness on the surface of the photosensitive layer, scattering solid powder on the surface of the photosensitive layer,
A method of providing a matte layer on the surface of a photosensitive layer as described in JP-A-50-125805, and JP-A-55
Examples include a method of heat-sealing a solid powder onto the surface of a photosensitive layer, as described in Japanese Patent No. 12974.

A positive-working photosensitive lithographic printing plate to which the photosensitive composition of the present invention is applied can be used in the same manner as conventional ones. It is exposed to light using a light source such as a tungsten lamp, and then developed with an alkaline developer, leaving only the unexposed portion on the surface of the support.
A positive relief image is created.

Examples of alkaline developers include sodium hydroxide,
Examples include aqueous solutions of alkali metal salts such as potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, sodium diphosphate, and sodium triphosphate.

The concentration of the alkali metal salt is preferably 0.1 to 10% by weight. In addition, an anionic surfactant, if necessary, is added to the developer.
Amphoteric surfactants and organic solvents such as alcohols can be added.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these embodiments.

Example 1 [Synthesis of binder] 4001 l of p-hydroxyaniline, 4 l of hydroquinone monomethyl ether, 41 g of acetone, and 360 g of pyridine were mixed and cooled from the outside using a cryogen until the internal temperature had fallen to -10°C. methacrylic acid chloride 4
20 g was added dropwise while stirring. The dropping rate was adjusted so that the reaction temperature was 0°C or less, and after the dropwise addition was completed, the mixture was stirred at 0 to 3°C for about 2 hours.

Next, after stirring at 25°C for 2 hours, the reaction solution was concentrated to 1/3, poured into 101 ml of diluted hydrochloric acid (DH about 1.0), and the resulting precipitate was suction-filtered to obtain a white solid. Obtained.

Dissolve this white solid in warm methanol 21, and add 5% sodium carbonate aqueous solution 2j! In addition, 40℃
The mixture was stirred for 30 minutes.

This dark red solution was then poured into 5% aqueous hydrochloric acid solution 81 to form a large amount of precipitate, which was filtered with suction and dried to give a pale pink solid. This was recrystallized from a mixed solvent of ethanol and water, and N-(4
-Hydroxyphenyl)acrylamide colorless needles 4
I got 50Q.

Said N-(4-hydroxyphenyl)acrylamide 1
06.4G, acrylonitrile 32g, ethyl acrylate 7.2Q, methyl methacrylate 73.2
g, and α, α′-azobisisoputyronitrile 6.5
6+I+ in acetone/methanol (1:1) mixed solvent 3
001 [After dissolving in nitrogen gas and purging with nitrogen gas, 4
The mixture was heated for a period of time to obtain a polymer solution. 3f of this polymer solution
The resulting white precipitate was filtered and dried to obtain a white polymer (Exemplary Compound No.
j! )>195g was obtained. When the weight molecular weight was measured by GPC, it was MW -3.5x104.

Below, the obtained binder resin is referred to as “binder resin [■
]”.

[Preparation of photosensitive planographic printing plate 1 An aluminum plate with a thickness of 0.24 mm was heated in a 5% aqueous sodium hydroxide solution at a temperature of 25°C and a current density of 60 A/df.
, processing time: 1 m: 30 seconds) chisel solution etching treatment was performed. Next, a desmut treatment was performed with a 5% aqueous sodium hydroxide solution, and then an anodization treatment was performed in a sulfuric acid solution. The amount of anodic oxide film was 20 g/df.

Next, it was immersed in a hot aqueous solution at 90'C to seal the holes.

Subsequently, a photosensitive coating solution having the composition shown below was coated on the aluminum support using a spin coater and dried at 100° C. for 4 minutes to obtain a photosensitive lithographic printing plate (A).

(Photosensitive coating liquid composition) Naphthoquinone-(1,2)-diazide-(2)-5-
Ester compound of sulfonic acid chloride and pyrogallol acetone resin (compound described in JP-A-60-143345, Synthesis Example 2) 1.634 dopinder resin [I 3 4.870.2-trichloromethyl-5- (p-butoxystyryl)-1,
3,4-Oxadiazole (compound described in JP-A-54-74728; Exemplary Compound No. 10)
An ester compound of a novolac resin synthesized from 0.13 g p -tert-octylphenol and formaldehyde and naphthoquinone-(1°2)-diazide-(2)-5-sulfonic acid chloride (condensation rate 50 mol%, MW - 1700) 0.1
3゜Victoria Pure Blue BOH (manufactured by Hodogaya Chemicals) 0.065
g. Ethyl Cellosolve θγ Gu. Methyl Cellosolve 33-112 The coating weight after drying was about 241 (1/dw').

A step tablet for sensitivity measurement (N manufactured by Eastman Kodak Company) was placed on the thus obtained photosensitive lithographic printing plate (A).
002, 21 levels of gray scale with a density difference of 0.15) in close contact, and a 2KW metal halide lamp (Idolfin 2000 manufactured by Iwasaki Electric) as the light source.
Exposure was performed for 70 seconds under the conditions of mW/Cf.

When this sample was developed with a 4% potassium metasilicate aqueous solution at 25° C. for 45 seconds, the non-image area was completely removed and a lithographic printing plate was obtained. When the sensitivity was measured using the gray scale of the step tablet, the fourth stage was completely developed (
clear).

Next, in order to examine visual acceptability, we prepared a developer solution with a diluted alkali concentration and a developer solution with a higher alkali concentration than the standard 4% potassium metasilicate aqueous solution. Developability using a developer with reduced developing ability (under-developability) using an exposed sample
Also, the developability with respect to a developer with excessive developing ability (over-developability) was investigated. In examining under-developability, the film was developed with 2.3% and 2.1% potassium metasilicate aqueous solutions at 25° C. for 45 seconds, and the solubility of the non-image area was determined. The more diluted the developer dissolves the photosensitive layer in the non-image area, the better the under-developability will be. In addition, to examine over-developability, development was performed at 25°C for 60 seconds with a 6.0% potassium metasilicate aqueous solution and at 25°C for 90 seconds with a 7.2% potassium metasilicate aqueous solution, and the number of solid stages was determined. (The lowest number of stages at which the photosensitive layer remains completely in the gray scale of the step tablet) is measured, and this is compared with the number of solid stages when standard development (4% potassium metasilicate aqueous solution, 25°C, 45 seconds) is carried out. The difference was calculated. The smaller the difference in the number of solid steps is and the closer it is to standard development, the less erosion of unexposed areas and the better the over-development performance.

Good development tolerance means that both under-development property and over-development property are good.

Furthermore, in order to examine resistance to processing chemicals, durability against plate cleaner and cleaning oil, which are used as a cleaning liquid to remove background stains that occur in non-image areas during printing, was investigated. The printing plate on which the image with the gray scale step-like density difference was formed was immersed in the stock solutions of FD plate cleaner (manufactured by Toyo Ink Co., Ltd.) and Uv plate cleaner (manufactured by Moroya Ink Co., Ltd.) for 12 hours at room temperature, and the same process was carried out. , UV plate cleaning solution Best Cure (manufactured by Toka Dye Chemical Co., Ltd.), UV plate cleaning solution Tsurfit (manufactured by Clarei Soprene Chemical Co., Ltd.) undiluted solution for 1.0 minutes, rinsed with water, and compared with the image area before immersion. The degree of erosion against treatment chemicals was measured.

Next, in order to examine the exposure visibility, the density of the exposed and unexposed areas of the exposed sample before development was measured under the above conditions using a densitometer (Sakura Densitometer PDA-65 manufactured by Roku Konishi Photo Industry Co., Ltd.).
' Red filter was used). It means that the larger the density difference ΔD, the better the exposure visible image quality.

Table 1 shows the results of the sensitivity, development tolerance, processing chemical resistance, and exposed visible image properties obtained above.

Comparative Example 1 From the photosensitive coating liquid of Example 1, the above-mentioned binder resin [
A photosensitive lithographic printing plate (B) was obtained by applying and drying a photosensitive lithographic printing plate (B) in the same manner as in Example 1 to which a same amount of the following novolac resin [I] was added except for Novolac resin [I].

・Novolac resin [I] Resin obtained by copolycondensation of phenol, -mono-cresol, p-cresol and formaldehyde (ratio of phenol/l-cresol/p-cresol during synthesis was 40/36/24, weight average molecular weight MW 10200, number average molecular weight Mn −1
300) 4.87g The coating weight after drying was about 24 mQ/df.

Using this photosensitive lithographic printing plate (B), the sensitivity, development tolerance, processing chemical resistance, and exposure visible image quality were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 2-tric00methyl-5 from the photosensitive coating liquid of Example 1
・-(p-butoxystyryl)-1,3゜4-oxadiazole (compound described in JP-A-54-74728: Exemplary Compound No. 10) is excluded, and instead, naphthoquinone-1 , 2-diazide-(2)-4-sulfonyl chloride in the same amount was coated on the same support as in Example 1 and dried in the same manner as in Example 1 to obtain a photosensitive lithographic printing plate (
'C) was obtained.

The coated weight after drying was approximately 241 Mdf.

Using this photosensitive lithographic printing plate (c), the sensitivity, development tolerance, processing chemical resistance, and exposure visible image quality were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 The above-mentioned binder resin [I
] and 2-trichloromethyl-5-(p-butoxystyryl)-1,3,4-oxadiazole, and instead of the novolac resin [I]4 described in Comparative Example 1.
4.87g naphthoquinone-1゜2-diazide-(2)
-4-Sulfonyl chloride 0.139 was added to the same support as in Example 1 and dried in the same manner to obtain a photosensitive lithographic printing plate (D).

The coating weight after drying was approximately 24mMdf.

Using this photosensitive lithographic printing plate (D), the sensitivity, development tolerance, processing chemical resistance, and exposure visible image quality were evaluated in the same manner as in Example 1. The results are shown in Table 1 for treatment chemical resistance. Mark A indicates slight erosion in the image area.

Mark B indicates erosion as above, and the grains of the support under the photosensitive layer are slightly exposed.

Mark C shows significant erosion as above, and the grains of the support below the photosensitive layer are completely exposed.

It means that.

In addition, in terms of under-developability, Mark Q indicates that the photosensitive layer in the non-image area has been completely dissolved and removed.

Part of the Δ mark remains as above.

The X mark indicates that the same as above is hardly dissolved.

It means that.

Regarding over-developability, the numerical value means the difference in the number of solid stages from standard development, and the - mark means that the erosion of the image area is so severe that the over-developability is so bad that the number of solid stages can hardly be determined.

From the results of the above Examples and Comparative Examples, the following is clear. That is, from the comparison between Examples and Comparative Examples, photosensitive lithographic printing plates (B) of Comparative Examples 1 to 3 other than Example 1 to
(D) has a significant defect in at least one of the properties shown in Table 1. That is, the photosensitive lithographic printing plate (B) had poor under-developability and processing chemical resistance;
The photosensitive planographic printing plate (c) has poor over-developability and exposure visible image quality, and the photosensitive planographic printing plate (D) has poor processing chemical resistance.

In the photosensitive planographic printing plate (A), by combining the binder resin of the present invention and the compound of the present invention that generates free radicals when exposed to actinic rays, the photosensitive planographic printing plate (B)
The disadvantages of using each of them alone, such as those of the and photosensitive lithographic printing plate (c), are eliminated, and the processing chemical resistance and sensitivity are better than when the binder resin [I] is used alone.
It can be seen that the performance has further improved.

Example 2 The binder resin [I] was removed from the photosensitive coating solution of Example 1, and the same amount of the following binder resin [I] was added instead to the same support as in Example 1. The coating was coated and dried to obtain a photosensitive planographic printing plate (E).

- Binder resin [n] Acetal obtained by reacting polyvinyl alcohol and roseoxybenzaldehyde (compound described in Example 1 of Japanese Patent Publication No. 5G-8658) The coating weight after drying was about 241 Mdf.

Using this photosensitive lithographic printing plate (E), sensitivity, development tolerance, processing chemical resistance, and exposure visible image quality were evaluated in the same manner as in Example 1. As a result, the above photosensitive lithographic printing plate (
Like the photosensitive lithographic printing plate (A) of Example 1, E) was found to be comprehensively excellent in sensitivity, development tolerance, processing chemical resistance, and exposure visible image quality.

(Effects of the Invention) As explained above, by using the photosensitive composition of the present invention, the photosensitive composition of the present invention has excellent resistance to processing chemicals, especially resistance to plate cleaners and cleaning solutions used in U-ink printing, and A photosensitive lithographic printing plate was obtained which had visible imageability upon exposure and was also excellent in sensitivity and development tolerance.

Claims (1)

[Claims] A photosensitive composition comprising (a) a quinonediazide compound, (b) a compound that generates free radicals upon irradiation with actinic rays, and (c) a vinyl copolymer.