JPH01307741A - Photosensitive lithographic printing plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a positive-working photosensitive lithographic printing plate containing O-quinonediazide.

Background of the Invention] Photosensitive 1 of a positive-working photosensitive lithographic printing plate generally contains an 0-quinonediazide compound as a photosensitive component and an alkali-soluble resin as a component for increasing film strength and alkali solubility.

It has been known to contain an organic acid in the photosensitive layer of such a positive-working photosensitive lithographic printing plate for the purpose of preventing scumming. However, in photosensitive lithographic printing plates containing such FM acids, there is a tendency for sensitivity, halftone reproducibility, especially small dot reproducibility, safe fly 1~ness, ballpoint pen suitability, etc. to deteriorate, and in particular, halftone dot reproducibility tends to deteriorate. As for the reproducibility, this variation in reproducibility is manifested as a change in gradation, which is a serious problem, and especially when the dot reproducibility is poor, this causes a big problem in the reproducibility of highlight areas in the resulting printed matter. In order to improve the reproducibility of small dots mentioned above, methods such as reducing the exposure amount during exposure are carried out, but although such methods improve the reproducibility of small dots to some extent, they conversely reduce the reproduction of midpoints and defects. This had the disadvantage of deteriorating properties.

For this reason, there has been a desire for the organic acid-containing photosensitive lithographic printing plate described above, which has excellent dot reproducibility without decreasing sensitivity, as well as excellent safelight properties and ballpoint pen suitability.

Here, "safelight property" refers to the resistance to light fog when the photosensitive planographic printing plate is made under white fluorescent light, and "ballpoint pen resistance" refers to the resistance to so-called multi-sided printing on the photosensitive planographic printing plate. This shows the resistance to ink of a ballpoint pen used for marks, etc. for positioning film originals when performing such operations.

[Object of the Invention] An object of the present invention is to provide a photosensitive lithographic printing plate in which the reproducibility of halftone dots, particularly small dots, is improved without reducing sensitivity.

Another object of the present invention is to provide a photosensitive lithographic printing plate that has excellent safelight properties and ballpoint pen suitability.

[Structure of the Invention] The object of the present invention is to provide a photosensitive lithographic printing plate having a photosensitive layer containing an 0-quinonediazide compound, an alkali-soluble resin, and an organic acid on a support; This was achieved by a photosensitive lithographic printing plate characterized in that the content m is greater at least in a region near the surface of the photosensitive layer on the side closer to the support than in a region near the surface of the photosensitive layer on the side farther from the support.

[Specific Structure of the Invention] In the present invention, if the content of dextral acid in the photosensitive layer is higher in the area near the surface of the photosensitive layer on the side closer to the support than in the area near the surface of the photosensitive layer on the side farther from the support. Any content distribution may be shown, but in particular, the organic acid content in a region within a distance of 50% of the total photosensitive layer thickness from the photosensitive layer surface on the side closer to the support is far from the support. [1
11] is preferably higher than the content in the region within the range from the surface of the photosensitive layer to a distance of 50% of the total thickness of the photosensitive layer.

Further, the content of the organic acid is 40% by weight or less of the total organic acid contained in the photosensitive layer on the side far from the support at a distance of 50% of the thickness from the surface of the photosensitive layer, and 40% by weight or less of the total organic acid contained in the photosensitive layer. It is preferable that the near side contains 60ffi1% or more,
Further, on the side far from the support, 30% or less of the total organic acids contained in the photosensitive layer, and on the side close to the support, 70% of the total organic acids contained in the photosensitive layer.
It is preferable that the above is included.

Specifically, in the photosensitive layer, the organic acid content decreases continuously from the surface of the photosensitive layer near the support toward the surface of the photosensitive layer far from the support, and it decreases discontinuously. It is preferable that at least one part of the material has an unchanged content, that is, a negative content part, and furthermore, within the scope of the present invention, it is preferable that at least one part of the content is present on the side farther from the support than on the side closer to the support. ! It also includes those having a portion with a high monoacid content. It also includes combinations of the above various patterns. Furthermore, the organic acid content may change linearly at a constant rate of change from the surface of the photosensitive layer near the support to the surface of the photosensitive layer far from the support, or the rate of change may be increased or decreased in a curved manner. It may be changed while changing.

Preferably, a photosensitive lithographic printing plate having a photosensitive layer having an organic acid content pattern as shown in (a) to (h) of FIG. 1 is desirable.

Furthermore, photosensitive lithographic printing plates having such an organic acid distribution have the same composition. It can be produced by sequentially applying a plurality of coating liquids that differ only in acid concentration. 2 As the organic acid used in the present invention, all known various organic acids can be used, but those having a pKa value of 2 or more are preferable, and more preferably those having a pKa value of 3.0 to 9.
0, particularly preferably 3.5 to 8.0. However, the pKa value used in the present invention is a value at 25°C.

Examples of such organic acids include, for example, 1.
Examples of such compounds include benzoic acid, adipic acid, and azelaic acid. , isophthalic acid, p-toluic acid, Q-1-ruic acid, β-ethylglutaric acid, m-oxybenzoic acid, p-oxybenzoic acid, 3,5-dimethylbenzoic acid, 1,3,4-dimethoxybenzoic acid , glyceric acid, gluta, conic acid, glutaric acid, p-anisic acid, succinic acid, sebacic acid, β, β-diethylglutaric acid, 1,1-cyclobutanedicarboxylic acid,
1.3-cyclobutanedicarboxylic acid, 1.1-cyclopentanedicarboxylic acid, 1.2-cyclopentanedicarboxylic acid, 1-13-cyclopentanedicarboxylic acid, β, β
-dimethylglutaric acid, dimethylmalonic acid, α-tartaric acid, speric acid, terephthalic acid, pimelic acid, phthalic acid,
Fumaric acid, β-propylglutaric acid, propylmalonic acid, mandelic acid, mesotartaric acid, β-methylglutaric acid, β
, β-methylpropylglutaric acid, methylmalonic acid, malic acid, 1,1-cyclohexanedicarboxylic acid, 1.2
-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cis-4-cyclohexene 1,2-dicarboxylic acid, and the like.

Other organic acids having an enol structure such as Meldrum's acid and ascorbic acid can also be preferably used. The proportion of the above-mentioned specific acid in the photosensitive layer is 0.05 to 10% by weight.
is suitable, preferably 0.1 to 5 weight26.

Examples of the O-quinonediazide compound in the present invention include ester compounds of O-naphthoquinonediazide sulfonic acid and polycondensation resins of phenols and aldehydes or ketones.

Examples of the phenols include phenol, 0-
Cresol, m-cresol, p-cresol, 3,5
- Monohydric phenols such as xylenol, carvacrol, and thymol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and 70 loglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, ace1-aldehyde, crotonaldenide, and furfural. Preferred among these are formaldehyde and benzaldehyde. Also, examples of the ketone include acetone, methyl ethyl ketone, and the like.

Specific examples of the polycondensation resin include phenol/formaldehyde resin, m-cresol/formaldehyde resin, m-, p-mixed cresol/formaldehyde resin, resorcinol/benzaldehyde resin, pyrogallol/acetone resin, etc. .

The overall conversion rate of O-naphthoquinonediazide sulfonic acid to the OH group of the phenol in the O-naphthoquinonediazide compound (reaction rate to one OH group) is 15 to 80%.
is preferable, and more preferably 20 to 45%.

Furthermore, as the orthoquinone diazide compound used in the present invention, the following compounds described in JP-A-58-43451 can also be used. For example, 1,2-
Known 1.2-quinonediazide compounds such as benzoquinonediazide sulfonic acid ester, 1.2-naphthoquinonediazide sulfonic acid ester, 1.2-benzoquinonediazide sulfonic acid amide, and 1.2-naphthoquinonediazide sulfonic acid amide, more specifically "Lie! - Sensitive" by J. Kosar.
System J
3systems”) pages 339-352 (1965
John Wiley and Sons
Wiley & 5ons (New York) and W varnish Day Forest (W, S,
"Photoresist J ("
Photoresis Volume 50.

(1975), McGraw-H
1, 2 listed in New York)
-benzoquinonediazide-4-sulfonic acid phenyl ester, 1.2.1',2', -di<benzoquinonediazide-4-sulfonyl)-dihydroxybiphenyl,
1.2-Benzoquinonediazide-4-(N-ethyl-he-β-naphthyl)-sulfonamide, 1.2-naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1-(1,2-naphthoquinonediazide-5- sulfonyl)-3゜5-dimethylpyrazole, 1,2-naphthoquinonediazide-5-sulfonic acid-4"-human 0oxydiphenyl-4"-azo B-naphthol ester, N,N
-di(1,2-naphthoquinonediazide-5-sulfonyl)-aniline, 2'-(1,2-naphthoquinonediazide-5-sulfonyloxy)-1-hydroxy-anthraquinone, 1,2-butoquinonediazide-5- Sulfone? ! -2,4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfone IQ
-2,3゜4-trihydroxybenzophenone ester, 1゜Condensate of 2 moles of 2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of 4,4'-diaminobenzophenone, 1,2-naphthoquinonediazide-5-sulfone 2 moles of acid chloride and 4,4'-dihydroxy-1,1
'-Diphenylsulfone 1 mol condensate, 1,2-naphthoquinonediazide-5-sulfonic acid chloride 1 mol condensate and purbrogalin 1 mol, 1,2-naphthoquinonediazide-5-(N-dihydroagoethyl)-sulfone Examples include 1,2-quinonediazide compounds such as amides. Also, Special Publication No. 37-1953, No. 37-3
No. 627, No. 37-13109, No. 40-26126
No. 40-3801, No. 45-5604, No. 45-27345, No. 51-13013, JP-A-4
No. 8-96575, No. 48-63802, No. 48-6
1,2-quinonediazide compounds described in Patent No. 3802 can also be mentioned.

As the 0-quinonediazide compound of the present invention, each of the above compounds may be used alone, or two or more thereof may be used in combination. The proportion of the O-quinonediazide compound used in the present invention in the photosensitive layer is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight.

As the alkali-soluble resin in the present invention, various resins known in the art can be used, but a vinyl polymer having a novolac resin and a structural unit having phenolic water II in its molecular structure is particularly preferred.

Novolac resins preferably used in the present invention include:
Examples include resins obtained by condensing phenols and formaldehyde in the presence of an MFO medium; examples of the phenols include phenol, 0-cresol, m-cresol, p-cresol, 3.5-xylenol, 2 ．．
Examples include 4-xylenol, 2,5-xylenol, carvacrol, thymol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucin, and the like.

The above-mentioned phenolic compounds can be used alone or in combination with formaldehyde to obtain a resin. Among these, a preferred novolak resin is a resin obtained by copolycondensing formaldehyde with at least one selected from phenol, m-cresol (or -cresol), and p-cresol. For example, phenol/formaldehyde resin, l-cresol/formaldehyde resin, 0-cresol/formaldehyde resin, phenol/p-cresol/formaldehyde copolymer resin, l-cresol/p-cresol/formaldehyde copolymer resin, 0- Examples include cresol/p-cresol/formaldehyde copolycondensate resin, phenol/partially cresol/p-cresol/formaldehyde copolycondensate resin, and phenol/0-cresol/p-cresol/formaldehyde copolycondensate resin. Furthermore, among the above novolac resins, phenol/m
-Cresol/p-cresol/formaldehyde resins are preferred.

In the present invention, the above-mentioned novolac resins may be used alone or in combination of two or more.

The molecular award for the above novolac resin (polystyrene standard) is
Heavy 9 average molecular fuMv is 2.0X103~2, OX 1
04, the number average molecule ffiMn is 7.0×102 to 5.
It is preferable that the value is within the range of OX 1Q3, and more preferably, lylw is 3.0×103-6. Ox
103, Mn is 7.7x 1Q 2-・j, 2xlQ
The value is within the range of 3. The molecular weight of the novolak resin in the present invention is measured by the above-mentioned GPC.

Furthermore, the vinyl polymer having a structural unit having a phenolic hydroxyl group in its molecular structure, which is preferably used in the present invention, is a polymer formed by polymerization by cleavage of a carbon-carbon double bond. Polymers containing at least one structural unit of the following general formulas [I] to [VI] are preferred.

General formula [I] + CR+ R2-CR3+- 0-C○-B-OH General formula [■] →CR1R2-CR3→- C0NR1→1rB-OH General formula [I[[] % formula% General formula [rV] -+ CR+ R2-CR3← -0H General formula [Vl OH General formula [Vl] 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 or an alkyl group such as a methyl group or an ethyl group. R+ is a hydrogen atom, an alkyl group,
Represents an aryl group or an aralkyl group, preferably a hydrogen atom. A represents an alkylene group which may have a substituent connecting a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10, and 81. represents a phenylene group which may have a substituent or a naphthylene group which may have a substituent. In the present invention, among these, a copolymer containing at least one structural unit represented by the general formula [II] is preferred.

The vinyl polymer has a copolymer type structure,
In such a copolymer, the general formulas [I] to [V
Examples of monomer units that can be used in combination with at least one of the structural units represented by each of I] include ethylene, propylene, isobutylene, butadiene,
Ethylenically unsaturated olefins such as isoprene, such as styrene, α-methylstyrene, p-methylstyrene,
Styrenes such as p-chlorostyrene, acrylic acids such as acrylic acid and methacrylic acid, itaconic acid,
Unsaturated aliphatic dicarboxylic acids such as maleic acid and maleic anhydride, such as methyl acrylate, ethyl acrylate,
α-methylene aliphatic monocarboxes such as ln-butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, ethyl ethacrylate, etc. Esters of acids, such as nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide, and anilides such as acrylanilide, p-chloroacrylanilide, m-nitroacrylanilide, m-mel-xyacrylanilide, etc. , vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanide, etc. , for example 1-
Ethylene derivatives such as methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1-ditroethylene, such as N-vinylpyrol, N -vinylcarbazole, N-vinylindole, N
- Vinyl monomers such as N-vinyl compounds such as 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 are used in combination with at least one of the structural units represented by general formulas [11 to VI]. It shows excellent overall performance and is preferable. More preferred are methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate, and the like.

These monomers may be bonded in the vinyl polymer either in a block or random manner.

In the vinyl polymer, general formulas [11 to [VI
] The content of the structural units shown in each is 5 to 70
It is preferably mol %, particularly preferably 10 to 40 mol %.

Further, the proportion of the alkali-soluble resin in the photosensitive layer is 50 to 95% by weight, preferably 60 to 95% by weight.
It is 90% by weight.

The above-mentioned polymers may be used alone in the above-mentioned combination, or two or more may be used in combination in the photosensitive composition.

Typical examples of vinyl polymers used in the present invention are listed below. In addition, in the compounds exemplified below, Mw
is a heavy ω-average molecule], Mn is a number-average molecule; however, s, j!
, o, m and n each represent mol% of the structural unit.

Exemplary Compound (Bi) ru-Tsum 13 1) CHs The photosensitive layer of the photosensitive lithographic printing plate of the present invention further contains a compound having the following structural units [I] and/or [II] in its molecular structure. It is preferable to do so.

Structural unit [I] +CH2CH2O+- Structural unit [I] CH3 +CH2CH-0+- (In the formula, n represents an integer of 2 to 5000, ,) Structural unit [I] and/or [II] used in the present invention As a compound having one of the above structural units [I] and [■]
Any compound may be used as long as it has one or both, but in particular, in each of the structural units [I] and [I[], n is an integer within the range of 2 to 5000, and the boiling point is 240 ° C. or higher. Compounds are preferred, and more preferably n is an integer within the range of 2 to 500 and the boiling point is 2.
A compound whose temperature is 80°C or higher, and the most preferable one is n
is a compound within the range of 3 to 100.

Examples of such compounds include: - Polyethylene glycol (HO→CH, CH, O"1
rrH)・Polyoxyethylene alkyl ether (RO
(CHt CH20)n H) ・Polyoxyethylene alkylphenyl ether ・Polyoxyethylene polystyrylphenyl ether ・Polyoxyethylene-polyoxypropylene glycol (including block polymer and random polymer) ・Polyoxyethylene-polyoxy Brobylene alkyl ether (the terminal forms an alkyl ether) (however,
・Ethylene oxide derivatives of alkylphenol-pormarine condensates ・Polyoxyethylene polyhydric alcohol fatty acid partial esters such as CHO(CH2CH20)nH CH,0(CH2CH,0)nH ・Polyoxyethylene fatty acid esters (such as RCOO (CH2CH20> n H)・Polyoxyethylene F'/H: Examples include ruamine and the like.

Specifically, the following are preferable, for example.

Namely, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether alcohol ether, polyoxyethylene octylphenyl ether, polyoxyethylene ethylene octylphenyl ether, polyoxyethylene Ethylene sorbitan monolaurate, polyoni diethylene sorbitan monopalmitate monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, Polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, polyethylene glycol distearate, polyoxyethylene nonylphenyl ether formaldehyde condensate, oxyethylene oxybrobylene block copolymer, polyethylene glycol, tetraethylene glycol, etc. It is.

The proportion of the above compound in the photosensitive layer is preferably 0.1 to 2% by weight, more preferably 0.2 to 10% by weight, based on the total photosensitive layer.

Moreover, the above-mentioned compounds may be used alone or in combination of two or more types, as long as they are within the range of the above-mentioned content m.

In addition, in the present invention, the ♀ containing a compound having the structural units [I] and/or [II] in the molecular structure in the photosensitive layer is attached to the support in a region near the surface of the photosensitive layer on the side far from the support. It is preferable that the distribution is larger than the area near the surface of the photosensitive layer on the near side, and especially in the above-mentioned area within the range from the surface of the photosensitive layer on the side far from the support to a distance of 50% of the total thickness of the photosensitive layer. It is preferable that the content m of the compound is greater than the content in a region within the range from the surface of the photosensitive layer on the side closer to the support to a distance of 50% of the total thickness of the photosensitive layer.

Furthermore, as for the content 1 of the above-mentioned compounds, not more than 40 weight n% of the total of the above-mentioned compounds contained in the photosensitive layer is added to the support at a distance of 50% of the thickness from the surface of the photosensitive layer, on the side closer to the supporting body. It is preferable that 60% or more is contained on the side far from the
Further, it is preferable that the photosensitive layer contains 30% by weight or less of the above-mentioned compound in the photosensitive layer on the side closer to the support, and 70% or more by weight on the side far from the support.

Specifically, the content of the above compound in the photosensitive layer decreases continuously from the surface of the photosensitive layer far from the support toward the surface of the photosensitive layer close to the support, and it decreases discontinuously. Preferably, at least one part of the content does not change, that is, it has an equal content, and within the scope of the present invention, one part is closer to the support than on the side farther from the support. It also includes those having a portion where the content of the above compound is high. It also includes combinations of the above various patterns. Furthermore, the change in compound content from the surface of the photosensitive layer far from the support to the surface of the photosensitive layer close to the support may be linearly changed at a constant rate of change, or may be increased or decreased in a curved manner. It may be changed while changing.

In addition to the above-mentioned materials, pigments such as dyes and pigments, plasticizers, etc. may be added to the photosensitive layer of the photosensitive lithographic printing plate of the present invention, if necessary.

Furthermore, a lipophilic resin may be added to the photosensitive layer of the photosensitive lithographic printing plate of the present invention in order to improve the oil sensitivity. The photosensitive lithographic printing plate of the present invention can be formed by dissolving each of these components in the following solvents and coating and drying the solution on the surface of a suitable support to provide a photosensitive layer.

Examples of solvents that can be used to dissolve each component of the photosensitive composition forming the photosensitive layer of the present invention include cellosol, rubs such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate. , dimethylformamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, ]-]lichloroethylene methyl ethyl ketone, and the like. These solvents can be used alone or in combination of two or more.

Coating methods used in the present invention to provide the photosensitive layer on the surface of the support include conventionally known methods, such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating. etc. are possible. At this time, the coating amount varies depending on the application, but for example, the solid content is preferably 0.5 to 5.0 (1/i'').

Supports on which the photosensitive layer is provided in the present invention include metal plates made of aluminum, zinc, steel, copper, etc., metal plates plated or vapor-deposited with chromium, zinc, copper, nickel, aluminum, iron, etc., paper, and plastic films. Examples include glass plates, 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.

As the support for the photosensitive lithographic printing plate of the present invention, it is more preferable to use an aluminum plate that has been subjected to surface treatments such as graining, anodizing, and, if necessary, sealing.

Known methods can be applied to these treatments.

Generally, a photosensitive lithographic printing plate is exposed to light using a printing device and then developed with a developer. As a result, only the unexposed portion remains on the surface of the support, creating a positive-positive relief image.

As the developer used for developing the photosensitive lithographic printing plate of the present invention, an aqueous alkaline developer is suitable. Examples of the aqueous alkaline developing solution include sodium hydroxide, potassium hydroxide, mono-lithium carbonate, potassium carbonate, mono-lithium metasilicate, potassium metasilicate, sodium diphosphate, and sodium triphosphate. Examples include aqueous solutions of alkali metal salts.

(Example) [Production of aluminum plate] Aluminum plate with a thickness of 0.24IRQ+ (material: 1050
．． After degreasing H16) in a 5% by weight aqueous sodium hydroxide solution at 60°C for 1 minute, 1/l of 0.5
In molar hydrochloric acid aqueous solution, temperature: 25°C, current density: 6
Electrolytic etching treatment was carried out under the conditions of 0 A/dn'' and a treatment time of 30 seconds.Next, a desmut treatment was performed at 60°C for 10 seconds in a 5% by weight aqueous sodium hydroxide solution, and then in a 20% by weight sulfuric acid solution. Temperature: 20℃, current: degrees;
The anodic oxidation treatment was performed under the conditions of 3Δ/d vz and treatment time: 1 minute.

Furthermore, hot water sealing treatment was performed with hot water at 30°C for 20 seconds.
An aluminum plate as a support for lithographic printing plate material was produced.

Preparation of 10 Photosensitive Lithographic Printing Plate Samples A photosensitive composition coating liquid (1) having the following composition was coated on the aluminum plate prepared as described above using a wire bar at a solid content of 1.2 g per 1f, and then heated at 90°C for 40 minutes. Dry for a minute.

Further, 1.2 g of photosensitive composition coating liquid (2) having the following composition was similarly applied on the solid content per 1f and dried at 90°C for 4 minutes to obtain positive photosensitive lithographic printing plate sample 1. .

(Photosensitive composition coating liquid (1) composition) - Novolac resin A 6.71;
1.O-quinonediazide compound 1.50(Q
D-1) - Benzoic acid 0.4 Q. Victoria Pure Blue BOH 0.08g (manufactured by Hodogaya Kagakuen)) - Compound that generates halogen free radicals 0.15 (1 (
rad-1) ・Methyl cellosolve 50. ρ (Photosensitive composition coating liquid (2) composition) ・Novolac resin A 6.7g・
0-quinonediazide compound 1.5g (QD-
1) - Victoria Pure Blue B OH0,08+3 - Compound that generates halogen free radicals o, isg (rac
l-1) ・Ethyl Cellosolve 50 Sample the upper layer of the photosensitive lithographic printing plate, which was removed by 1q, at the thickness of 172 on the side far from the support, and measure the amount of benzoic acid contained in it. As a result, approximately 25% of the total m
There was a darkness.

Preparation of Photosensitive Planographic Printing Plate Samples 2 to 10 The specific materials and coating amounts of the photosensitive composition coating liquids (1) and (2) in the preparation of the above photosensitive planographic printing plate sample 1 were as shown in Table 1. Photosensitive lithographic printing plate samples 2 to 10 were obtained in the same manner as in the preparation of sample 1 except for the following changes.

Preparation of Photosensitive Planographic Printing Plate Samples 11 to 20 A photosensitive composition coating solution (3) having the following composition was applied to the aluminum plate prepared as described above, and a photosensitive composition coating solution (4) was applied thereon to the photosensitive planographic plate. The coating was applied and dried in the same manner as in the preparation of printing plate sample 1 to obtain photosensitive lithographic printing plate sample 11. Furthermore, lithographic printing plate samples 12 to 20 were obtained in the same manner as in the preparation of lithographic printing plate sample 11, except that the specific materials and coating amounts in coating solutions (3) and (4) were changed as shown in Table 1. .

(Photosensitive composition coating liquid (3) composition) -Novolac resin A' 6.3g
・O-quinonediazide compound 1.9g (Q
D-1) - Cis-1,2-cyclohexane 0.3g Dicarboxylic acid - Biku 1 Helia Pure Blue B OH 0.07g (manufactured by Odugaya Kagaku U) - Compound that generates halogen free rIim 0.131
7 (rad -2) - Methyl cellosolve 501g (photosensitive composition coating liquid (4) composition) - Novolac resin A 6.3 (1
・0-quinonediazide compound 1.9(1(Q
D-1) Isshi Odo JL, TW-0 120 0.3
g・Victoria Pure Blue BOH0.07g・Halogen: Compound that produces 111 groups 0.13(]
(rad -2) Methyl cellosolve 501g Preparation of photosensitive lithographic printing plate samples 21 to 23 The amount of p-toluic acid in the photosensitive composition coating liquid (1) used for the photosensitive lithographic printing plate sample N0.2 was is 0.2g, sample No. 2
(Same as ¥ made, solid content per 112 is 2.49
After coating and drying, photosensitive planographic printing plate sample N
o, 21 was prepared.

In addition, photosensitive lithographic printing plate samples Nos. 22 and 23 were prepared in the same manner as sample No. 021 except that the specific material of the photosensitive composition coating liquid (1) was changed as shown in Table 1.

Photosensitive lithographic printing plate samples No. 1 to 23 thus obtained
A step tablet for sensitivity measurement (N082 manufactured by Eastman Kodak, 21 levels of gray scale with a density difference of 0.15) and a Brunner chart were placed on top of the 4
Clear stage number is 5 using KW metal halide lamp as light source
Exposure was performed under the following conditions. At that time, the exposure count and the reproducibility of Brunner's 2% point were evaluated.

In addition, in order to evaluate the safelight property, the unexposed samples N011 to 23 were left in a bright room for 10 minutes, 15 minutes, and 20 minutes and exposed to light. It was developed with a twice diluted phenomenon solution (standard phenomenon solution) at 27° C. for 20 seconds, and the degree of erosion of the image area was evaluated by comparing it with that of a sample that was not exposed to light in a bright room.

Furthermore, in order to examine suitability for a ballpoint pen, drawings were drawn on the unexposed areas using a Pelikan ballpoint pen, and then developed in the same manner as above, and the damage (erosion r!) of the drawn areas was determined. The results are shown in Table 1.

The following margins are ", 4:・1" U: Umbrella 10-quinonediazide compound QD-1: 1,2-naphthoquinonediazide-5-sulfone M-2,3,II, 4'-tetrahydroxybenzophenone ester QD-2; ( X/V -1/3 MW of resin before reacting QD -1,600) QD
-3; MW of resin before reacting with QDs = 1,300 pieces 2 Novolac resin/Novolac resin A Copolycondensation resin of phenol, m-cresol, p-cresol, and formaldehyde (phenol, m-cresol, and p-cresol) The molar ratio of each cresol is 2.0:
4.8: 3.2, MW = 7,000, tvL
w /Mn -5,4) - Novolac resin B Copolymer resin of m-cresol, p-cresol and formaldehyde (molar ratio of each of a+-cresol and p-cresol is 6:4, MW -a,ooo, MW/M
n -5,7) $3 Compound having structural unit [I] and/or [I[] - Rheodol TW-0120 (manufactured by Kao); Polyoxyethylene sorbitan monooleate - Emulgen 920
(manufactured by Kao@): Polyoxyethylene nonylphenyl ether/polyethylene glycol (manufactured by Kanto Kagaku Co., Ltd.); Polyethylene glycol #2000 ・Emanon 1112 (manufactured by Kao ■): Polyethylene glycol monolaurate/Nilacol R
= 1010 (manufactured by Nikko Chemicals): polyoxyethylene nonylphenyl formaldehyde condensate, Rheodol 440 (manufactured by Kao ■); polyoxyethylene sorbitol tetraoleate, Emulgen 408 (manufactured by Kao); polyoxyethylene oleyl ether, Emulgen A-90 (Kao (manufactured by Tai); Polyoxyethylene derivative/Emulgen l-40 (manufactured by Kao ■); Polyoxyethylene W Q form/Emulgen pp-250 (Kao (manufactured by Tai); Oxyethylene/oxypropylene block copolymer Compound rad-1 that generates O halogen free radical; 2-trichloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole (described in Example 1 of JP-A-54-74728) Compound) rad-2:2-trichloromethyl-5-[β-(2-
benzofuryl)vinyl]1゜3.4-oxadiazole (exemplified compound (1) described in JP-A-60-138539) It was possible to provide a photosensitive lithographic printing plate with improved reproducibility of small dots.

In addition, the present invention could provide a photosensitive lithographic printing plate with excellent safelight properties and ballpoint pen suitability.

[Brief explanation of the drawing]

(a) to (h) in FIG. 1 show preferred concentration distributions of organic acids in the photosensitive layer of the photosensitive lithographic printing plate of the present invention. In the figure, u and S indicate the surface of the photosensitive layer on the side far from the support,
L and S indicate the surface of the photosensitive layer closer to the support. Figure 1

Claims (1)

[Claims] In a photosensitive lithographic printing plate having a photosensitive layer containing an o-quinonediazide compound, an alkali-soluble resin, and an organic acid on a support, the content of the organic acid in the photosensitive layer is at least on the side closer to the support. A photosensitive lithographic printing plate characterized in that the area near the surface of the layer is larger than the area near the surface of the photosensitive layer on the side farther from the support.