JPS62150353A - Photosensitive lithographic form plate - Google Patents

Abstract

PURPOSE:To obtain a photosensitive lithographic form plate superior in resistances to processing chemicals and printing by incorporating a specified o-quinonediazidosulfonate and a novolak resin in a photosensitive composition, and forming a specified roughened face on the surface of one side of a base same as that of photosensitive layers. CONSTITUTION:The photosensitive composition contains the o- quinonediazidosulfonate obtained by polycondensing di- or tri-valent phenol with a compound having a carbonyl group, and a novolak resin and the surface of the base on the side of the photosensitive layer has a face roughened so as to adjust a bearing contact face rate tpmi to 0-50% at the section depth 3 ties as long as a center line roughness Ra. The o-quinonediazidosulfonate to be used is such as the ester of benzoquinone-1,2-diazidosulfochloride or naphthoquinone-1,2-diazidosulfochloride with a pyrogallol-acetone resin. As the novolak resin, phenol-m-cresol-p-cresol formaldehyde resin is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positive type photosensitive lithographic printing plate, and more specifically to a photosensitive lithographic printing plate with excellent printing durability and processing chemical resistance. Regarding.

[Conventional technology]

O-quinonediazide compounds are widely used in photosensitive lithographic printing plates as photosensitive components that form positive-positive images.

However, photosensitive lithographic printing plates using such O-quinonediazide compounds are susceptible to attack by processing chemicals such as various acids and solvents used during printing operations, and this attack can reduce the printing durability of the printing plates. is bringing. For this reason, a photosensitive lithographic printing plate with excellent processing chemical resistance is desired.

In addition, the photosensitive lithographic printing plate using an 0-quinonediazide compound has a weak film strength of the photosensitive layer in the image area compared to a negative photosensitive lithographic printing plate, and the photosensitive layer in the image area and the support Because of the weak adhesion, the printing durability was poor.

Conventionally, several attempts have been made to improve the printing durability of positive photosensitive lithographic printing plates using O-quinonediazide compounds. Among them, JP-A No. 50-96504 and No. 5
0-11022 publications have a multi-layered photosensitive layer, and the upper layer contains a highly abrasion-resistant resin and an adhesion improver to increase the strength of the image and improve printing durability. The technology to do this is described. However, since the coating is performed using an organic solvent, it is difficult and impractical to provide a multilayered photosensitive layer due to production technology. Furthermore, it has the disadvantage of poor halftone dot reproducibility. Furthermore, as an attempt to improve the printing durability from the side of the support, Japanese Patent Application Laid-Open No. 133903/1983 discloses a grain-shaped pore size distribution as a support for planographic printing plates with high printing durability. and the center line average roughness is specified. However, although the grain shape indicated by the characteristic value of the pore diameter has good hydrophilicity and water retention to some extent, it cannot necessarily be said that it has good printing durability, and its resistance to processing chemicals is not good. Ta. Furthermore, JP-A-56-1
No. 50593, No. 56-150594 and No. 56-1
No. 50595, each publication states that a printing plate using a support with uniform pit diameters (microscopically uniform) and a deep grain shape has high water retention and printing durability.

[Problem that the invention seeks to solve]

However, none of them necessarily had excellent printing durability, nor did they have good treatment chemical resistance.

Therefore, an object of the present invention is to provide a photosensitive lithographic printing plate which has excellent processing chemical resistance and excellent printing durability. [Means for solving the problems] For example, the present invention relates to a photosensitive lithographic printing plate, which is a photosensitive lithographic printing plate in which a positive-working photosensitive composition is provided as a photosensitive layer on a support made of anodized aluminum material as a base material. , the photosensitive composition comprises the following components (a) and (g): (a) 0-quinonediazide sulfonic acid of a polycondensation resin of divalent and/or trivalent phenols and a p-bonyl group-containing compound; Ester compound (b) contains a novolac resin, and the base material has a bearing contact area ratio (tpmi) of 0 to 0 at a cutting depth of 3 times the center line average roughness (Ra) on the surface on the photosensitive layer side. It is characterized by having a rough surface of 50%.

The present invention will be explained in detail below.

The polycondensation resin of divalent and/or trivalent pheno-ρ and a carbonyl group-containing compound in the present invention is produced by combining a pheno-μ having two and/or three hydroxyl groups and a carbonyl group-containing compound in an acidic catalyst. It is a resin obtained by polycondensation in the presence of phenols, and examples of the phenol μ include catechol μ, resoμ
Dihydric phenols such as cin, hydroquinone, pyrogallo-μ
and trihydric phenols such as phloroglucin.

Among these, preferred are trivalent phenol and reso/
In terms of L/V, pyrogallol is more preferred. Examples of the carbonyl group-containing compound include acetone,
Examples include ketones such as methyl ethyl ketone and diethyl ketone, and aldehydes such as formaldehyde, acedo-μdehyde and benzaldehyde, with acetone and benzaldehyde being preferred.

A specific example of the polycondensation resin is reso-synform μm-dehyde [11! , v zorcin-benzaldehyde resin, pyrogallol-acetone resin, pyrogallol-
Examples include formaldehyde resin, phloroglucin-acetone resin, and the like.

Preferred among these are pyrogallol-acetone resin and resorcinol-benzaldehyde resin.

The molecular weight (polystyrene standard) of the polycondensation resin is a number average molecular weight Mn of 53 x 102 to 7.2 x 103, and a weight average molecular weight My! The range of tiX102 to 1.5×104 is suitable, and more preferably the range of Mn is 55×102 to
9.3×102, Mw is 5.0×102 to 4.0×10
The range is 3.

The molecular weight of the polycondensation resin is measured by gel permeation chromatography (hereinafter abbreviated as GPC). Calculation of Mn and Mvr is carried out according to Morio Tsuge, Tatsuya Miyabayashi, Masayuki Tanaka 6 "Journal of the Chemical Society of Japan" Vol. pages 800-805 (
(1972) in which the peaks of the oligomer region are leveled (the centers of the peaks and valleys are connected).

In the synthesis of 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. The blending ratio of phenols and carbon-di-group-containing compounds during synthesis is 1 mo μ part of phenol/l/group-containing compound.
17 to 1.0 mole part is used. However, when ketones are used as the reaction solvent, the mixing ratio is not limited to the above. Examples of the reaction solvent used include alcohols such as methanol and ethanol, acetone, water, and tetrahydrofuran.

The reaction is carried out at a predetermined temperature (usually 0 to 120°C) for a predetermined time (
Usually 3 to 24 hours). After the reaction is completed, the reaction solution is poured into water, and the precipitated solids are separated and dried, or the reaction solvent of the reaction solution is concentrated, washed with water, and further dehydrated to produce a liquefied product. The sample is taken out, spread and solidified to obtain a reactant.

The 0-quinonediazide sulfonic acid ester compound of the present invention can be obtained by dissolving the above polycondensation resin in a suitable solvent such as dioxane.

-Quinone diazito esterified by adding μphonic acid chloride and adding dropwise alkali carbonate to the equivalence point while heating and stirring.

In the ester compound, the condensation rate of 0-naphthoquinonediazide sulfonic acid chloride with respect to the hydroxyl group of pheno-μ (reaction rate with respect to one hydroxyl group) is 5 to 50.
The content is preferably 10% to 50%, and even more preferably 10% to 40%. The condensation rate is calculated by determining the content of sulfur atoms in the sulfony μ group by elemental analysis.

Typical specific examples of the 0-quinonediazide sulfonic acid ester compounds include benzoquinone-(1,2)-diazide sulfonic acid or naphthoquinone-(1,2)-diazito μphonic acid chloride and pyrogallol-acetone Jugetsuji. Examples include esters of

The amount of the 0-quinonediazide sulfonic acid ester compound in the photosensitive composition of the present invention is preferably 5 to 70% by weight, particularly preferably 10 to 50% by weight.

The 0-quinone diazito p-phonic acid ester of the present invention has Mw
is preferably in the range of 5.0x102 to 1.7x104, more preferably in the range of 7-OXlo'' to 50x103.The Mn is 0x101 to aOX10
It is preferably in the range of S, more preferably 4.0
The range is from X102 to 1.5X10S.

When Mw is less than 5.0×102, durability against processing chemicals used during printing is poor;
When it exceeds 104, the sensitivity decreases.

The measurement of Mn and My of the esterified product was performed using the GP described above.
Perform by method C.

The novolak resin of the present invention has a phenolic tophomoμ μ
It is obtained by polycondensing dehyde in the presence of an acidic catalyst.
Examples of pheno-IVs include monohydric phenols such as pheno-, FL/, 0-cresol, m-cresol, p-cunzol, xylenol, baculo-μ, thymo-μ, and α-naphthol, catechol, resorcinol, and hypo-naphthol. Examples include dihydric phenols such as hydroquinone, pyrogallo-A', and trivalent phenols such as hyphlologousin. Among these, a copolycondensation resin of formaldehyde and at least one selected from phenol, 0-talesol, m-cresol, and p-cresol is preferred.

Specific examples of novolac resins include phenol-formaldehyde resin, m-cresol-formaldehyde resin, 0-cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensate resin, m-cresol-formaldehyde resin,
-Cresol-p-cresol-formaldehyde copolycondensate resin, 0.-Frezi-1'L/-p-cresol μ
・Formaldehyde copolycondensate resin, JP-A-55-57
Pheno-μ-m-creso/L'-p-cresol-formaldehyde copolycondensate resin, pheno-μ-0-creso/L'-p-cresol-formaldehyde copolymer described in Publication No. 841 Examples include condensate resins. In addition, examples of polycondensation resins of polyhydric phenols and formaldehyde include catechol-formaldehyde resins and hydroquinone-formaldehyde resins described in JP-A-59-86046.

Among the above novolak resins, pheno-μm coke reso-
/L'-p-cresol-formadehyde resin is preferred.

The content of the novolac resin in the photosensitive layer is preferably 30 to 95% by weight, more preferably 50 to 85% by weight based on the total solid content of the photosensitive layer.

The molecular weight of the novolak resin is preferably Mn of 4.
0X10" ~ 4.5X10", My is 2.0X10
'~1.5x104, more preferably Mn is 1.0x
10”~50X10”, My is &0X103~1.5×
It is 104. The molecular weight of the resin is measured in the same manner as for the 0-quinone diazito μphonic acid ester.

In addition to the materials described above, the photosensitive layer of the present invention can also contain other additives as necessary. As plasticizers, various low-molecular-weight compounds such as evaphthalic acid NTE, triphenyl phosphates, maleic esters are used, and as coating property improving agents, surfactants such as fluorine monosurfactants, ethyphenyl esters are used.
Examples include nonionic activators such as cellulose boria μ-kylene ether, and preton-out materials that form visible images upon exposure. The print-out material is composed of a compound that generates acid or free radicals when exposed to light, and an organic dye that changes its color tone by interacting with it. Examples of compounds that generate acid or free radicals when exposed to light include: Japanese Patent Publication No. 50-562
0-Naphthoquinonediazide-4-sulfonic acid halide described in Publication No. 09, JP-A-55-5622
Trihalomethyl A/-2-pyrone and trihalomethyl-triazine described in Publication No. 5, JP-A-55-624
0-Naphthoquinonediazide described in Publication No. 4
Ester compounds of 4-sulfonic acid chloride and pheno-μ or anilines having electron-withdrawing substituents, halomethyp-vinyμm oxadiazo-μ compounds and diazonium described in JP-A-55-77742 Examples include salt.

Examples of the organic dyes include Victoria Purep/l/-BOH (manufactured by Udogaya Chemical Co., Ltd.), Oil Blue φ603 (manufactured by Orient Chemical Co., Ltd.), Patent Purep~- (manufactured by Sumitomo Mikuni Chemical Co., Ltd.), and Crystal Violet, brilliant clean, ethyl violet, methyl green, erythrosin B1 basic tsuksin, mafkite green, oil red, m-cresol barb~, rhodamine B1 auramine, 4-p-diethyμ aminophenylimino naphthoquinone, cyano-p-diethylamino Triphenylmethane type, diphenylmethane type, oxazine type, represented by phenylacetanilide, etc.
Examples include xanthine threads, iminonaphthoquinone threads, azomethine-based or anthraquinone-based dyes.

Furthermore, in order to improve the oil sensitivity, it is possible to add a photosensitive resin obtained by condensing lipophilic phenol formaldehyde resin and p-[6 phenol formaldehyde resin with sulfonic acid chloride of o-quinonediazide. can. These oil sensitizers account for 0.1 to 5 of the total composition of the photosensitive layer.
Preferably, the content is % by weight.

Further, a sensitizer for improving sensitivity can also be added to the photosensitive composition of the photosensitive layer of the present invention. As a sensitizer, a gallic acid salt conductor described in JP-A-57-118237, a 5-membered cyclic acid anhydride as described in JP-A-52-80022, such as anhydrous lid y
acids, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, pyromellitic acid, itaconic acid, etc., and 6-membered cyclic acid anhydrides as described in JP-A-58-11932. Examples include glutaric anhydride and its derivatives. Among these, cyclic acid anhydrides are preferred, and 6-membered cyclic acid anhydrides are particularly preferred.

In the photosensitive lithographic printing plate of the present invention, the photosensitive composition constituting the photosensitive layer may be mixed with various solvents, such as cellosolp such as methyl cellosolve, ethyl cellosolve, methyl heptarosobacterium acetate, ethyl cellosub acetate, dimethylformamide, etc. , dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl .mu.ketone, etc., and a mixed solvent of two or more of the above to prepare a photosensitive coating solution, and apply this to the surface of the anodic oxide film side of the uninvented support. It can be formed by coating and drying.

In the present invention, an anodized aluminum material is used as a base material for the support, and in addition to pure aluminum, alloys mainly composed of aluminum, such as silicon, magnesium, iron, copper, zinc, Including TLTR aluminum alloys such as manganese, chromium, bismuth, nickel, etc.

As the aluminum material used in the present invention, rolling method,
A plate-shaped (including foil-shaped) aluminum material manufactured by hot-dip aluminum plating or the like can be used. Aluminum materials manufactured by molten aluminum plating are
A metal plate such as a steel plate is plated with a molten aluminum bath and has an aluminum layer preferably having a thickness of 7 μm or more.

The base material in the present invention has a center line average roughness Ra of 0.4 to
0.9 μm1 Preferably, it is 0.5 to 0.8 μm, and the contact area ratio (Bearing Area tpmi) of the bearing at a cutting depth of 3 times Ra is 0 to 50.
H, preferably has a rough surface of 0 to 35%.

Center Line Aver
age) (Ra) is German standard DIN 4768
As defined in
g Area TPMI) is German standard DIN47
Abbott load curve C described in 62-3.2.2.3
Bearing Area Curve (Abbot
t ) ), the value (9 g) at a specific cutting depth can be determined.

If the contact area ratio (TPMI) of the bearing is more than 50 inches, the adhesion between the support and the photosensitive layer will decrease, and the processing chemical resistance and printing durability will decrease.

Next, methods for forming the surface shape of the base material in the present invention include, for example, a mechanical method and an electrolytic etching method. Mechanical methods include, for example, bow/
Examples include l/polishing method, brush polishing method, polishing method using liquid honing, and puff polishing method. Among these, the method of etching by electrolysis is preferred. Abrasives used in mechanical polishing include alumina, silicon carbide, chromium oxide, red iron, tungsten carbide, poron carbide, diamond, sand, silica, granite, limestone, artificial emery, steel balls, iron pieces, and aluminum. Examples include random, bumiston, and magnesium oxide. Etching methods using electrolysis include phosphoric acid, sulfuric acid,
Examples include etching methods using solutions containing perchloric acid, hydrochloric acid, nitric acid, birophosphoric acid, hydrofluoric acid, and the like. When producing a roughened aluminum material, the various methods described above can be used alone or in combination depending on the composition of the aluminum material.

Electrolytic etching is carried out in a bath containing one or a mixture of two or more of the above inorganic acids. Among these, preferred are sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, or a mixture of two or more of these, and particularly preferred is a bath containing nitric acid or hydrochloric acid as a main component. In addition, organic acids such as alcohol, acetic anhydride, and unsaturated acid, inorganic substances such as potassium dichromate and hydrogen peroxide, colloids such as gelatin and starch, glycerin, and other viscous substances, and surfactants can be added to the bath as additives. These additives may be used alone or in combination of two or more. The electrolytic etching bath is prepared by adding the above-mentioned acids and, if necessary, the above-mentioned additives to water.

The concentration of the bath during electrolytic etching is IIL1-10,
The bath temperature is preferably in the range of 10 to 50°C, the applied voltage is in the range of 10 to 100 V, the current density is in the range of 1 to 100 A/dm2, and the electrolysis time is in the range of 3 to 300 seconds.

When performing electrolytic elatincula, degreasing and cleaning can be performed to remove oil, fat, rust, dirt, etc. from the surface of the aluminum material. Degreasing treatments include solvent degreasing, which removes dirt using petroleum-based solvents or chlorinated hydrocarbons such as trichlorethylene and perchlorethylene, and solutions made by emulsifying nonionic surfactants, solvents such as trichlorethylene and kerosene, and water. Examples include emulsion degreasing using an alkaline chemical, alkaline degreasing using boiling in a treatment solution containing an alkaline chemical, and electrolytic degreasing.

Alkaline chemicals used for alkaline degreasing include sodium hydroxide, sodium carbonate, sodium silicate,
A surfactant such as sodium phosphate may also be added.

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.

The aluminum material used in the present invention is then subjected to anodization treatment. When electrolysis is performed using aluminum as an anode using sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid, etc. or a mixture of two or more of these as the electrolyte, an anodic oxide film is formed on the aluminum surface. be done.

The electrolytic conditions are acid concentration 1-70% by weight, current density 1-70% by weight.
60 A/dm", bath temperature 10~65℃, applied voltage 1~
100v, 11! A solution time range of 10 seconds to 10 minutes is appropriate. The amount of anodic oxide film formed in this way is 5 to 70
■/dm” is appropriate, preferably 15 to 50 Wq
/dm", more preferably in the range of 25 to 40 η/dm". The amount of anodized film can be determined, for example, by immersing an aluminum plate in a phosphoric acid chromic acid solution [prepared by dissolving 85% phosphoric acid solution 35 mA and chromium oxide (Vl) 20.9 in 1 t of water] to dissolve the oxide film. , which can be determined by measuring changes in weight before and after dissolving the film on the plate.

In the present invention, "using an anodized aluminum material as the base material" refers to the anodized film surface of the aluminum material (the film surface has the specific surface shape of the base material of the present invention).
It means that a photosensitive layer is provided on the plate surface so as to constitute a printing plate surface, and the anodized film includes the one in which the film surface is subjected to a surface treatment. For example, in the present invention, an anodized aluminum material may be used as a support so that a photosensitive layer is coated on the anodized film surface, or an anodized aluminum material may be used as a support so that a photosensitive layer is coated on the anodized film surface of the anodized aluminum material. A surface-treated material may be used as a support so that a photosensitive layer is provided on the surface-treated surface, or an anodized aluminum material with a lining or other treatment may be used. It may also be used as a support. This surface treatment includes, for example, pore sealing treatment, undercoating with an aqueous solution of a water-soluble polymer compound and a water-soluble salt, etc., performed on the anodized surface. Examples of the sealing treatment include boiling water treatment, steam treatment, sodium silicate treatment, and dichromate solution treatment.

When the roughened aluminum material is thin like foil, a metal plate, plastic film, paper, etc. may be attached to the back surface directly or via an adhesive layer.

When using the photosensitive lithographic printing plate of the present invention, a known method is applied, in which a positive film is adhered, exposed to light using an ultra-high pressure mercury lamp, metal halide film, etc., and developed with an alkaline developer. used as.

Examples of the alkaline developer include aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, potassium metasilicate, sodium diphosphate, sodium triphosphate, etc.
The concentration of the alkaline agent is preferably 0.1 to 10% by weight.

〔Example〕

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 An aluminum plate with a thickness of 124 m was subjected to surface roughening treatment using a rotating nylon brush using an abrasive and water suspension, washed with water, and then alkaline etched in a 10 ml aqueous solution of caustic soda. After washing with water, the surface was washed and neutralized by immersing it in a 30% nitric acid aqueous solution at room temperature for 1 minute. After washing with water, anodic oxidation treatment was performed in a 30% sulfuric acid aqueous solution at 60° C. and 6 A/dm'' for 50 seconds, followed by pore sealing treatment with hot water.

The surface roughness of this support [I] was measured. The surface roughness meter is a belt meter (Pe) manufactured by Perthen.
rthometer) S 5 P under the following seven rules conditions.

Needle cartridge: RT-50C (diamond needle,
Radius of needle tip: 5 μm) Needle sensitivity adjustment: Pen-10-1, adjusted based on 90 μm Profile lv: Roughness profile R Vertical magnification: 2.5 μm Horizontal magnification: 250 μm Measurement length: 4. 0 simple cut-off value: Q, 8mm In the obtained centerline average roughness (Ra) and Abbott load curve, the contact surface ratio of the bearing at a cutting depth of 3 times the value of the centerline average roughness (Ra) The value of (tpmi) is as follows.

Center line average roughness Ra = 0.61 Bearing brightness ratio tpmi = 22% Next, a photosensitive coating liquid having the following composition was applied onto the support CI) using a rotary coating machine, After drying for a minute, a photosensitive lithographic printing plate was obtained.

[Photosensitive coating liquid composition]

0 naphthoquinone-(1,2)-diazide-(2) -5
- Ester compound of sulfonic acid clophyte and pyrogallol-acetone resin (Mw = 1800, NTep conversion rate per 1 pheno-μ hydroxyl group 30%) 1.8011O phenol and m''-, p-mixed cresolt formaldehyde copolycondensation resin (synthesized by charging each molar ratio of phenol, m-Frezy ~ and p-cresol at a ratio of 20:48:32, Mn = 1393, Mw - 7358)
& 4 Novolac resin synthesized from gop-t-buty p-phenoltoform acid (Mv=2000) 16F10 Victoria Pure Blue BOH [manufactured by Odugaya Kagaku Co., Ltd.], 07go Ethyl cello μ Bu 80 + dO Methiμ Cellophore 20rnl.

The coating weight after drying was approximately 22 rNi/d m2.

The above-mentioned molecular weight measurement was performed using the above-mentioned GPC,
The measurement conditions are as follows.

Equipment + if: Model 655 manufactured by Hitachi, Separation force ram: Shodex A 80 manufactured by Showa Denko K.K.
2. Connect A303 and A304 in series, temperature:
A calibration curve was prepared using polystyrene as a standard at room temperature, solvent: tetrahydrofuran, flow rate: 1.5 g/min.

A step tablet (manufactured by Eastman Kodak Company) for measuring the degree of badness was placed on the thus obtained photosensitive lithographic printing plate (G).
Short 2, 21 levels of gray scale with a density difference of 0.15/
l/) and positive original film, and then use a 2kw metal hafide hump [idle fin 2 manufactured by Iwasaki Electric Co., Ltd.].
000:) as a light source and under the condition of a o my/α2,
Exposure was made for 70 seconds. Next, this sample was developed with a 4% potassium metasilicate aqueous solution at 25° C. for 45 seconds, and the non-image area was completely removed to obtain a lithographic printing plate.

When the sensitivity was measured using the gray scale of the step tablet, the s572nd stage was completely developed (clear).

Next, in order to examine processing chemical resistance, we examined Ultra Plate Cleaners CA, B, C, and Chemiyoku/L, which are used as cleaning solutions to remove background stains that occur in non-image areas during printing.
/ manufactured by Co., Ltd.] was measured.

The printing plate, on which an image with a density difference was formed on the gray scale steps, was immersed in μtra plate cleaner stock solution at room temperature for 45 minutes, washed with water, dried, and compared with the unsoaked image area. The degree of corrosion of the image area against processing chemicals was determined. As a result, the printing plate had no erosion in the image area and exhibited good treatment chemical resistance.

Next, in order to examine printing durability, printing was performed using the above lithographic printing plate on an offset printing machine (Hamada Star 900CDX), and the printed matter obtained before the image area was damaged and printing became impossible. The printing durability was evaluated based on the number of sheets. As a result, when the above lithographic printing plate was used, up to 250,000 copies of good printed matter were obtained. In addition, the lithographic printing plate was smudge-free during printing and had good water retention.

Comparative Example 1 The following photosensitive coating solution was applied to the support CI) prepared in Example 1 and dried in the same manner as in Example 1 to form a photosensitive lithographic printing plate (CI).
I got it.

[Composition of photosensitive coating liquid]

0 naphthoquinone-(192)-diazide-(2) -5
- Ester compound of sulfonic acid chloride and m-cresol formaldehyde novolac resin (Mw=, 1
800, condensation rate 25%) 1g Copolycondensation resin of phenol, m-1p-mixed creso-μ, and formaldehyde (the molar ratio of phenol, m-cresol, and p-cresol was 20:48:32)
Un-1395, M
w -7358) 51g Novolac fat synthesized from op-t-butylphenol and formaldehyde (My-2000) (116g o Victoria Pure Blue BOH [manufactured by Odugaya Chemical Co., Ltd.] α0790 Ethyl Cellosolve 100 - After drying The coating weight was approximately 22 η/dm''.

The molecular weight was measured in the same manner as in Example 1.

Next, using this photosensitive lithographic printing plate CB), Example 1
Similarly, treatment chemical resistance and printing durability were examined. The results are shown in Table 1 below along with other examples.

Comparative Example 2 Aluminum plate with thickness Q, 24 sam (material 1050,
After degreasing the tempered H16) in a caustic soda aqueous solution, it was immersed in 30 sulfuric acid to neutralize it, and then washed with water. Next, in a 11.6 molar hydrochloric acid aqueous solution, current density: 50 A
/dm", treatment time: 40 seconds. Next, after desmutting in a caustic soda aqueous solution, desmutting was performed in a 30ts sulfuric acid solution at 30°C.
Anodic oxidation treatment was performed for 30 seconds under 6A/dm20 conditions. Furthermore, this was subjected to a sealing treatment using hot water.

The surface roughness of this support (II"l) was measured in the same manner as in Example 1. The results were as follows: Center line average roughness (Ra) = 1178 Bearing contact area ratio (TPMI) - 68%.

Next, the same photosensitive coating agent as in Example 1 was coated and dried on the support (It), and the photosensitive planographic printing plate (
C) was obtained.

The coating weight after drying was approximately 22 .mu./dm''.

Next, the test was carried out using this photosensitive lithographic printing plate (C).

The results are shown in Table 1.

Comparative Example 3 On the support [■] in Comparative Example 2, the photosensitive coating g1. in Comparative Example 1 was applied. CB) was coated and dried in the same manner as in Example 1 to obtain a photosensitive planographic printing plate CD).

The coating weight after drying was approximately 22*/dm''.

Next, using this photosensitive lithographic printing plate CD), Example 1
In the same manner as above, treatment chemical resistance and i@printing force were examined.

The results are shown in Table 1.

As mentioned above, the sensitivity performed for Example 1 and Comparative Examples 1 to 3,
Table 1 summarizes the measurement results of treatment chemical resistance and printing durability.

In Table 1, Mark A shows almost no erosion in the image area.

Mark B shows slight erosion as above.

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

A mark D means that significant erosion is observed and the grains of the support below the photosensitive layer are completely exposed.

From the above Examples and Comparative Examples, although the sensitivities are almost the same, there are large differences in performance in treatment chemical resistance and printing durability. First, the effect of the support alone is that the printing durability increases by 100,000 sheets from the comparison of Comparative Example 1 and Comparative Example 3. It can be seen that the effect of the quinonediazide sulfonic acid ester compound) alone increases the level of treatment chemical resistance by two ranks. However, as is clear from the comparison between Example 1 and Comparative Example 3, the effect of combining the two is that the printing durability increases by 150,000 sheets, and the processing chemical resistance V-pel increases by 3.
The rank has increased, and it was found that the sum of the above two individual effects was greater than that of the courtesy one.

〔Effect of the invention〕

As explained above, the photosensitive lithographic printing plate of the present invention has remarkable effects in that it has excellent printing durability and excellent durability against processing chemicals such as plate cleaners used during printing operations. be.

Claims (1)

[Claims] 1. A photosensitive lithographic printing plate in which a positive-working photosensitive composition is provided as a photosensitive layer on a support made of anodized aluminum material, in which the photosensitive composition is , below (a
) and (b) components: (a) an o-quinonediazide sulfonic acid ester compound of a polycondensation resin of divalent and/or trivalent phenols and a carbonyl group-containing compound (b) a novolac resin; The photosensitive lithographic plate is characterized in that the surface on the photosensitive layer side has a rough surface having a bearing contact surface ratio (TPMI) of 0 to 50% at a cutting depth three times the center line average roughness (Ra). Print version. 2. The weight average molecular weight Mw of the polycondensation resin is 3.3×
The photosensitive lithographic printing plate according to claim 1, wherein 10^2≦Mw≦1.5×10^4. 3. The photosensitive lithographic printing plate according to claim 1, wherein the ester compound has an esterification rate of 10 to 40% per phenolic hydroxyl group. 4. The weight average molecular weight Mw of the novolak resin is 2.0.
The photosensitive lithographic printing plate according to claim 1, wherein ×10^3≦Mw≦1.5×10^4. 5. The contact area ratio (tpmi) of the bearing of the base material is 0.
35%. The photosensitive lithographic printing plate according to claim 1, wherein the photosensitive lithographic printing plate has a content of 35%.