JPH11194489A - Photosensitive composition for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive composition for a litho-graphic printing plate high in sensitivity, underdevelopability, overdevelopability, resistance to chemicals, exposure image-visualizability, and gradation. SOLUTION: This photosensitive composition for a lithographic printing plate comprises a novolak resin obtained by condensation of phenols composed essentially of pure phenol with aldehydes or ketones and a quinonediazido compound, and this novolak resin has an area of 30-90% and 0-40% and 20-90% of the total area of GPC patterns in the range of a weight average molecular weight of 6,000-30,000 and 2,000-5,000 and 150-1,000 in terms of a monodispersed polystyrene measured by the gel permeation chromatography(GPC), that is, the novolak resin comprises a combination of two or more kinds of the novolak resins different from each other in the weight average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a positive photosensitive composition containing a quinonediazide compound and a binder resin suitable as a photosensitive layer of a positive photosensitive lithographic printing plate, and more particularly to a binder resin. Things.

[0002]

2. Description of the Related Art A photosensitive composition used in a photosensitive layer of a positive photosensitive lithographic printing plate includes various processing chemicals used in printing together with sensitivity, gradation (high contrast) and developability. ,
For example, resistance (chemical resistance) to a solvent contained in a plate cleaner or the like is required.

[0003] As such a positive photosensitive composition,
The following technologies have been proposed.

As a positive resist for high integration having excellent resolution, sensitivity, developability and heat resistance, a positive-type radiation-sensitive resin composition comprising an alkali-soluble novolak resin and a 1,2-quinonediazide compound is used. As a novolak resin, 30 to 90 mol% of m-cresol and 70 to 10 mol% of phenols represented by the general formula
Is obtained by condensing phenols containing formaldehyde with formaldehyde, and has a polystyrene-equivalent molecular weight of 6,300 to 25,000, as determined by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.
When the maximum height values of the peaks in the range of 2,500 to 6,000 and 150 to 900 are a, b and c, respectively, a / b = 0 to 1.5 and c / b = 0. 5-1.
A positive radiation-sensitive resin composition using a resin in the range of No. 5 (JP-B-6-54386). However, when this resin composition is applied to a photosensitive lithographic printing plate, sensitivity, under-developability (allowable range of reduction in developing ability to obtain an appropriate development result), gradation, chemical resistance and over-development ( Satisfactory performance cannot always be obtained in the range of prolonged development time in which an appropriate development result can be obtained.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a planographic printing plate having good sensitivity, under-developability, gradation, chemical resistance and over-developability. An object of the present invention is to provide a photosensitive composition for a plate.

[0006]

Means for Solving the Problems The constitution of the present invention for achieving the above object of the present invention is as follows (1) to (4).

(1) In a photosensitive composition for a lithographic printing plate containing a quinonediazide compound and a novolak resin obtained by condensing a phenol containing phenol as an essential component with an aldehyde or ketone, monodisperse polystyrene of the novolak resin The weight average molecular weight in terms of polystyrene, determined by a gel permeation chromatography (GPC) method using as a standard, is 6,000 to 30,000, 2,000.
G in the range of 0-5,000 and 150-1,000
The area value of the PC pattern is 30
A photosensitive composition for a lithographic printing plate, wherein the composition is from 90% to 90%, from 0 to 40% and from 20 to 90%.

(2) The photosensitive composition for a lithographic printing plate as described in (1) above, wherein the novolak resin is a novolak resin obtained by combining at least two kinds having different weight average molecular weights.

(3) The photosensitive composition for a lithographic printing plate as described in (1) above, wherein the quinonediazide compound is a quinonediazidesulfonic acid ester of a novolak resin obtained by condensing phenols with aldehydes or ketones. .

(4) The photosensitive composition for a lithographic printing plate as described in (3) above, wherein the quinonediazide compound has a weight average molecular weight of 2,000 to 5,000.

Hereinafter, the present invention will be described in detail.

The novolak resin contained in the photosensitive composition for a lithographic printing plate according to the present invention is a novolak resin obtained by condensing a phenol containing phenol as an essential component with an aldehyde or a ketone, and The weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard is from 6,000 to 30,000, 2,0.
The area values of the GPC patterns in the range of 00 to 5,000 and 150 to 1,000 are 3
Novolak resins having 0 to 90%, 0 to 40%, and 20 to 90% (hereinafter referred to as "molecular weight distribution of the present invention").

Specific examples of the phenols used in the production of the novolak resin include phenol and m- or p-alkylphenol. Examples of the phenol include monovalent, divalent, and trivalent phenols such as catechol, resorcin, hydroquinone, and pyrogallol, but monovalent phenol is preferable. Examples of m-alkylphenol include m-cresol, 3,5-xylenol, carvacrol, thymol, and the like,
As p-alkylphenol, p-cresol, 2,
4-xylenol and the like. These phenols can be used alone or in combination.

Examples of the aldehydes include formaldehyde, acetaldehyde, benzaldehyde, acrolein, methacrolein, crotonaldehyde, acrolein dimethyl acetal, furfural, and the like. Preferred are formaldehyde and benzaldehyde. As formaldehyde, an aqueous formaldehyde solution (formalin) and paraformaldehyde which is an oligomer of formaldehyde can be used.
In particular, 37% formalin is industrially produced in large quantities, which is advantageous. Examples of ketones include acetone and methyl ethyl ketone.

As the method for producing the novolak resin of the present invention, a known method used for this kind of reaction, in particular, a method for producing a high-ortho novolak resin can be appropriately applied. For example, an organic acid salt of a specific divalent metal as shown in Japanese Patent Publication No.
A method of addition-condensation of a phenol containing m- / p-mixed cresol with an aldehyde under the conditions of or after partially condensing the phenol and the aldehyde with an organic acid salt of a divalent metal as a catalyst, There is a method of performing addition condensation using an acid as a catalyst. Also, J.I. Appl. Chem 1
957, pages 676-688,
A method of adding and condensing phenols with aldehydes using a hydroxide or oxide of a divalent metal as a catalyst, or a method of partially adding and condensing phenols and aldehydes with a hydroxide or an oxide of a divalent metal as a catalyst Thereafter, there is a method in which addition condensation is carried out using an acid as a catalyst.

A method of adding an aqueous solution of formalin to phenols prepared by mixing m- / p-cresol at a predetermined ratio and condensing the mixture with triethylamine (JP-A-3-253589, JP-A-3-253860) issue),
There is a method in which phenols and paraformaldehyde are dissolved in a non-polar solvent such as toluene, and heated to a high temperature under pressurized conditions. Acid catalysts such as oxalic acid are widely used in the production of novolak resins, but the resin produced by the method of producing a high-ortho novolak resin has a lower X value than the resin obtained by the usual production method of a novolak resin. Tends to be higher. In the present invention, it is preferable to apply a method using an organic acid salt or oxide of a divalent metal as a catalyst.

In the present invention, the weight average molecular weight of the novolak resin is a weight average molecular weight in terms of polystyrene determined by a gel permeation chromatography (GPC) method using monodisperse polystyrene as a standard. As preferred conditions for GPC, a column manufactured by Tosoh (GMHXL 2
Book), a flow rate of 1 ml / min, and an elution solvent tetrahydrofuran.

In the present invention, the weight average molecular weight is 5,000
The area value of the GPC pattern in the range of 0 to 2,000 exceeds 40% with respect to the entire area, and 30,000 to 6,000
If the ratios are less than 30% and less than 20%, respectively, the gradation, chemical resistance and over-developability deteriorate.

In order to obtain the novolak resin having the molecular weight distribution of the present invention, the synthesis conditions are adjusted (for example, the solvent composition).
Alternatively, a method of separating the reaction products by a fractionation precipitation method or the like and mixing them so that the molecular weight distribution of the present invention is obtained, or a method of mixing novolak resins having different weight average molecular weights synthesized in separate batches is used. Can be applied. The fractional precipitation method is described in "Basics of Polymer Experiments-Molecular Characteristic Analysis" Kyoritsu Publishing (1
994) p. 206 to 216 can be referred to.

As the novolak resin having a molecular weight distribution of the present invention, for example, a novolak resin having a narrow molecular weight distribution produced by applying the production method described in JP-A-9-124756 can be used.

The amount of unreacted monomer in the novolak resin of the present invention is at most 5 mol%, preferably at most 2 mol%. If the amount of the unreacted monomer is more than 5 mol%, it is not preferable because chemical resistance may be deteriorated or printing performance may be reduced. Reduce the amount of unreacted monomer in the resin to 2
In order to reduce the content to less than mol%, for example, after the condensation reaction, the purpose can be achieved by increasing the degree of vacuum.

The proportion of the novolak resin in the lithographic printing plate photosensitive composition of the present invention (at the time of forming the photosensitive layer) is usually 30 to 95% by weight, more preferably 50 to 90% by weight.
% By weight.

Examples of the quinonediazide compound used in the present invention include an ester of o-naphthoquinonediazidesulfonic acid and a polycondensation resin of a phenol and an aldehyde or ketone. Examples of the phenols of these polycondensation resins include monovalent phenols such as phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, carvacrol, and thymol, and divalent compounds such as catechol, resorcinol, and hydroquinone. Phenol,
And trihydric phenols such as pyrogallol and phloroglucin. As the aldehyde, formaldehyde,
Examples include acetaldehyde, benzaldehyde, crotonaldehyde, and furfural. Examples of the ketone include acetone and methyl ethyl ketone.

Specific examples of these polycondensation resins include:
Phenol / formaldehyde resin, m-cresol /
Formaldehyde resins, m- and p-mixed cresol / formaldehyde resins, resorcin / benzaldehyde resins, pyrogallol / acetone resins, and the like. o-
The ester ratio of o-naphthoquinonediazidesulfonic acid to OH groups of phenols in a polycondensation resin of a naphthoquinonediazide compound (reaction rate per OH group) is:
15-18% is preferred, more preferably 20-45%
It is.

Further, as the quinonediazide compound used in the present invention, the following compounds described in JP-A-58-43451 can be used. That is, for example, well-known 1,2- such as 1,2-benzoquinonediazidosulfonic acid ester, 1,2-naphthoquinonediazidosulfonic acid ester, 1,2-benzoquinonediazidosulfonic acid amide, and 1,2-naphthoquinonediazidosulfonic acid amide. And quinonediazide compounds.

More specifically, J. Kosal (JK)
osar), "Light Sensitive Systems"
("Light-Sensitive System
s ") pp. 339-352 (1965), John Wiley & Sons.
Sons, Inc. (New York) and WS De Forest, "Photoresist", Vol. 50, (1975), McGraw Hill
1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, 1,2,1 ', 2'-di- (benzoquinonediazide-4-sulfonyl) -dihydroxyphenyl, as described in W-Hill), New York. ,
1,2-benzoquinonediazide-4- (N-ethyl-N
-Β-naphthyl) -sulfonamide, 1,2-naphthoquinonediazido-5-sulfonic acid cyclohexyl ester, 1- (1,2-naphthoquinonediazide-5-sulfonyl) -3,5-dimethylpyrazole, 1,2- Naphthoquinonediazide-5-sulfonic acid-4 ″ -hydroxydiphenyl-4 ″ -azo-β-naphthol ester, N,
N-di- (1,2-naphthoquinonediazido-5-sulfonyl) -aniline, 2 '-(1,2-naphthoquinonediazide-5-sulfonyloxy) -1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-5 -Sulfonic acid-2,4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfonic acid-
2,3,4-trihydroxybenzophenone ester,
Condensate of 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mol of 4,4'-diaminobenzophenone; 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 4,4'-dihydroxy- 1,1 '
Condensate of 1 mol of diphenylsulfone, 1 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mol of purprogalin, 1,2-naphthoquinonediazide-5- (N-dihydroabiethyl) -sulfonamide And 1,2-quinonediazide compounds. No. 37-1953, 37-362
No. 7, No. 37-13109, No. 40-26126,
No. 40-3801, No. 45-5604, No. 45-2
Nos. 7345 and 51131013, JP-A-48-9
No. 6575, No. 48-63802, No. 48-6380
The 1,2-quinonediazide compound described in each of JP-A No. 3 can also be mentioned.

In the present invention, the quinonediazide compound contained in the photosensitive composition is preferably a quinonediazidesulfonic acid ester of a novolak resin obtained by condensing phenols with aldehydes or ketones. The weight average molecular weight is preferably in the range of 2,000 to 5,000. When the weight average molecular weight is less than 2,000, chemical resistance is particularly deteriorated, and when it exceeds 5,000, sensitivity, under developability and gradation are particularly deteriorated.

The above compounds may be used alone or in combination of two or more. The proportion of the quinonediazide compound in the photosensitive composition (at the time of forming the photosensitive layer) of the present invention is preferably from 5 to 70% by weight, particularly preferably from 10 to 50% by weight.

The photosensitive composition of the present invention may contain other additives as required in addition to the above-mentioned materials. Examples of the plasticizer include various low-molecular compounds, such as phthalates, triphenyl phosphates, and maleic esters, and surfactants such as fluorine-based surfactants and ethylcellulose polyalkylene ethers as coating improvers. And a printout material for forming a visible image by exposure.

The printout material comprises a compound that generates an acid or a free radical upon exposure to light and an organic dye that changes its color tone by interacting with the compound. Examples of the compound that generates an acid or a free radical upon exposure include: For example, o-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A-50-36209, trihalomethyl-2-pyrone and trihalomethyl-triazine described in JP-A-53-36223. O- described in JP-A-55-6244.
Ester compounds of naphthoquinonediazide-4-sulfonic acid chloride with phenols or anilines having an electron-withdrawing substituent, halomethyl-vinyl-oxadiazole compounds described in JP-A-55-77742, and diazonium And the like.

Examples of the organic dyes include Victoria Pure Blue BOH [Hodogaya Chemical], Oil Blue # 603 [Orient Chemical], Patent Pure Blue [Sumitomo Mikuni Chemical], Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Green, Erythrosin B, basic fuchsin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4-p-diethylaminophenylimino naphthoquinone, triphenylmethane series represented by cyano-p-diethylaminophenylacetanilide, diphenylmethane series And oxazine, xanthene, iminonaphthoquinone, azomethine and anthraquinone dyes. Of these, triphenylmethane dyes are preferred.

A sensitizer for improving the sensitivity can be added to the photosensitive composition of the present invention. Examples of the sensitizer include gallic acid derivatives described in JP-A-57-118237 and 5-membered cyclic acid anhydrides described in JP-A-52-80022, for example, phthalic anhydride. , Tetrahydrophthalic anhydride, maleic anhydride,
Examples thereof include succinic anhydride and the like, and 6-membered cyclic acid anhydrides described in JP-A-58-11932, such as glutaric anhydride and derivatives thereof. Among these, a cyclic acid anhydride is preferable, and a 6-membered cyclic acid anhydride is particularly preferable.

Further, a lipophilic resin can be added to the photosensitive composition of the present invention in order to improve the oil sensitivity of the photosensitive composition.

Each component of the photosensitive composition of the present invention is as follows:
A photosensitive layer can be formed by dissolving in a solvent as shown below and applying and drying it on the surface of a suitable support to form a photosensitive lithographic printing plate.

Solvents that can be used for dissolving each component include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, dimethylformamide, dimethylsulfoxide, dioxane, acetone, cyclohexanone, and the like.
Examples include carbitols such as trichloroethylene, methyl ethyl ketone, diethylene glycol dimethyl ether, diethylene glycol methyl ether, and ethyl carbitol; propylene glycols such as propylene glycol monomethyl ether acetate; and ethyl lactate. Of these, carbitols, propylene glycols, ethyl lactate and the like are preferably used from the viewpoint of toxicity to the human body. These solvents may be used alone or in combination of two or more.

As the coating method used for coating the photosensitive composition on the surface of the support, there are conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and curtain coating. Coating or the like is possible. At this time, the amount of application varies depending on the application, but for example, a solid content of 0.5 to 5.0 g / m ² is preferable.

In a photosensitive lithographic printing plate having the photosensitive composition of the present invention as a photosensitive layer, a support on which a photosensitive layer is provided, such as a metal plate of aluminum, zinc, steel, copper, and the like, chromium, zinc, copper, nickel, Examples thereof include a metal plate, paper, plastic film and glass plate on which aluminum or iron is plated or vapor-deposited, paper coated with a resin, paper on which a metal foil such as aluminum is stretched, a plastic film subjected to hydrophilic treatment, and the like. Of these, an aluminum plate is preferred. As the support of the photosensitive lithographic printing plate, it is more preferable to use an aluminum plate which has been subjected to surface treatment such as graining treatment, anodic oxidation treatment and, if necessary, sealing treatment. A known method can be applied to these processes.

Examples of the graining method include a mechanical method and an electrolytic etching method.
Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a puff polishing method. The various methods described above can be used alone or in combination depending on the composition of the aluminum material and the like. Preferred is a method by electrolytic etching.

In the electrolytic etching, phosphoric acid, sulfuric acid, hydrochloric acid,
The reaction is carried out in a bath containing one or more inorganic acids such as nitric acid. After the graining treatment, if necessary, a desmut treatment is performed with an aqueous solution of an alkali or an acid to neutralize and wash with water.

The anodic oxidation treatment is carried out by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid, etc. as an electrolytic solution, and using an aluminum plate as an anode for electrolysis. The amount of anodic oxide film formed is 1 to 50 m
g / dm ² is suitable, and preferably 10 to 40 mg / g.
dm ² . The amount of the anodic oxide film is determined, for example, by placing an aluminum plate on a chromic phosphate solution (phosphoric acid 85% solution: 35 ml,
Chromium oxide (VI): 20 g is dissolved in 1 liter of water) to dissolve the oxide film, and it can be determined by measuring the change in weight before and after dissolution of the film on the plate.

Examples of the sealing treatment include a boiling water treatment, a steam treatment, a sodium silicate treatment, a dichromate aqueous solution treatment and the like. In addition, the aluminum plate support may be subjected to an undercoating treatment with an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconic acid.

The photosensitive lithographic printing plate having the photosensitive composition of the present invention as a photosensitive layer can be subjected to development processing by a usual method. For example, exposure is performed through a transparent positive film using a light source such as an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or a tungsten lamp, and then development is performed using various alkali developing solutions. Only this unexposed portion remains on the support surface to form a positive-positive relief image.

Examples of the alkali developer include alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, dibasic sodium phosphate and tertiary sodium phosphate. Aqueous solution. The concentration of the alkali metal salt is preferably from 0.1 to 10% by weight. In addition, an organic solvent such as an anionic surfactant, an amphoteric surfactant or an alcohol can be added to the developer, if necessary.

[0044]

Next, the present invention will be described more specifically with reference to Production Examples and Examples, but the present invention is not limited to these Production Examples and Examples. In the following description, the weight average molecular weight is based on GPC.

Production of Novolak Resin Production Example 1 In a 300 ml separable flask, 3.48 g of phenol, 42.4 g of meta-cresol, 27.2 g of para-cresol, and 4 of formalin (37% aqueous solution)
6.5 g and oxalic acid 0.16 g were charged, heated and stirred in a 110 ° C. oil bath for 4 hours, and reacted to dry the product under reduced pressure to obtain a novolak resin. The weight average molecular weight of this resin is 9,20.
It was 0.

<Production Example 2> A novolak resin was produced in the same manner as in Production Example 1 except that 3.48 g of phenol, 30.4 g of metacresol, 45.6 g of paracresol, and 37.47 g of formalin (37% aqueous solution) were used. did. The weight average molecular weight of the obtained resin was 2,000.

<Production Example 3> 60 g of the resin of Production Example 1 was added to 50
The resin precipitate was dissolved in 0 ml of methanol, and 140 ml of water was added dropwise to the resin solution under stirring, and the resulting resin precipitate was dried under reduced pressure. The weight average molecular weight of the obtained resin was 12,000.

<Production Example 4> 60 g of the resin of Production Example 2 was added to 50
The resin solution was dissolved in 0 ml of methanol, and under stirring, 300 ml of water was added dropwise to the resin solution to remove the formed resin precipitate.
The supernatant was distilled under reduced pressure to dry the resin. The weight average molecular weight of the resin thus obtained was 1,000.

<Production Example 5> A novolak resin was produced in the same manner as in Production Example 1 except that 41.78 g of phenol, 19.2 g of meta-cresol, and 6.4 g of para-cresol were used. Thus, a fractionated precipitation resin was obtained. The weight average molecular weight was 12,500.

<Production Example 6> A novolak resin was produced in the same manner as in Production Example 2 except that 41.78 g of phenol, 19.2 g of meta-cresol, and 6.4 g of para-cresol were used. Thus, a fractionated precipitation resin was obtained. The weight average molecular weight was 1,100.

<Production Example 7> A novolak resin was obtained in the same manner as in Example 8 of JP-A-9-124756, except that 7.1 g of phenol, 92.3 g of meta-cresol, and 61.6 g of para-cresol were used. . The weight average molecular weight of this resin was 8,200.

<Production Example 8> A novolak resin was obtained in the same manner as in Example 2 of JP-A-9-124756, except that 7.1 g of phenol, 92.3 g of meta-cresol, and 61.6 g of para-cresol were used. . The weight average molecular weight of this resin was 2,200.

<Production Example 9> 24.7 g of phenol (0.
263 mol), 324 g (3 mol) of meta-cresol and 244 g (2 mol) of para-cresol were used in the same manner as in Example 1 of JP-B-6-54386 to obtain a novolak resin.

<Production Example 10> 16 g of phenol (0.1
7 mol), 216 g (2 mol) of meta-cresol, ter
A novolak resin was obtained in the same manner as in Example 4 of JP-B-6-54386 except that 300 g (2 mol) of t-butylphenol was used.

<Production Example 11> A novolak resin was obtained in the same manner as in Example 1 of JP-B-6-54386.

<Production Example 12> A novolak resin was obtained in the same manner as in Example 4 of JP-B-6-54386.

<Production Example 13> 50 g of pyrogallol and 350 g of acetone were charged into a three-headed corbane set in a water bath, nitrogen gas was blown thereinto, the atmosphere was replaced with nitrogen, and 5 g of phosphorus oxychloride was charged to carry out a polycondensation reaction. went.
The reaction temperature was kept at 20 ° C and the reaction was carried out all day and night.
The resin is gradually added to the mixture while being vigorously stirred to precipitate the formed resin. Next, 60 g of this resin was mixed with 720 ml of dioxane.
After adding 70 g of o-naphthoquinonediazide-5-sulfonyl chloride and dissolving, 60 g of potassium carbonate aqueous solution (13% by weight) was added dropwise, and after performing a condensation reaction at 40 to 50 ° C. for about 1 hour, The reaction solution was poured into a large amount of dilute hydrochloric acid solution (concentrated hydrochloric acid 13 ml, water 1 l), and the precipitated resin was collected by filtration and dried to obtain a quinonediazide compound. The weight average molecular weight was 3,830.

<Production Example 14> In the synthesis of a condensation resin of pyrogallol and acetone, the weight-average molecular weight was the same as in Production Example 13 except for 50 g of pyrogallol, 150 g of acetone, 1 g of phosphorus oxychloride, a reaction temperature of 60 ° C. and a reaction time of 7 hours. 1,380 quinonediazide compounds were obtained.

<Examples and Comparative Examples> A 0.30 mm-thick aluminum plate (material 1050, tempered H16) was degreased in a 5% by weight aqueous sodium hydroxide solution at 65 ° C for 1 minute, and then washed with water. The electrolytic etching treatment was performed in a 0.5 mol aqueous hydrochloric acid solution at 25 ° C. and a current density of 60 A / dm ² for 30 seconds. Then, after a desmut treatment at 60 ° C. for 10 seconds in a 5% by weight aqueous sodium hydroxide solution, a 20% by weight aqueous sulfuric acid solution at a temperature of 20 ° C. and a current density of 3 A / dm.
^An anodic oxidation treatment was performed for 1 minute under the conditions of ² . Further, the substrate was washed with water, followed by sealing with a 2.5% aqueous solution of sodium silicate at 80 ° C. for 20 seconds, followed by washing with water to produce a support.

A photosensitive solution having the following composition was applied on the grained surface of the support so as to have a dry weight of 1.6 g / m ^2, and dried under a stream of air at 80 ° C. for 2 minutes. Lithographic printing plate samples (No. 1 to No. 8) were obtained.

[Photosensitive composition] Quinonediazide 1.0 g Novolak resin 2.5 g Triphenylmethane dye (trade name: Victoria Pure Blue BOH, manufactured by Hodogaya Chemical Co.) 0.03 g Fluorine surfactant (trade name: Florard FC430) 0.01 g methyl lactate 16 g propylene glycol monoethyl ether 4 g The quinonediazide compound and novolak resin used in the photosensitive solution of each of the above photosensitive lithographic printing plate samples are shown in Table 1 below.

[0062]

[Table 1]

In Table 1, Production Example N of quinonediazide compound
"Monomer Q" in the column of o. means a condensate of 1 mol of 2,3,4-trihydroxybenzophenone and 2.5 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride.

A positive image film original and a step tablet manufactured by Eastman Kodak Co. (one step having a transmission density difference of 0.15) were passed through each of the above photosensitive lithographic printing plate samples.
Exposure was performed at 8 mW / cm ² for 30 seconds using a 2 kW metal halide lamp using a PS plate baking machine.

The exposed sample was immersed for 30 seconds in a developing solution having the following composition adjusted to 25 ° C., gently rubbed with a sponge, and washed with running water to obtain a lithographic printing plate sample.

[Developer Composition] Potassium A silicate (manufactured by Nippon Chemical Co., Ltd.) 1000 ml Caustic potash 130 ml Pure water 5000 ml The sensitivity, gradation, under developability, over developability and chemical resistance of each photosensitive lithographic printing plate sample were determined. Evaluation was performed, and the results shown in Table 1 were obtained.

<Performance Evaluation Method> The sensitivity, gradation, under developability, over developability, and
The chemical resistance and the visible light exposure were evaluated, and the results shown in Table 2 were obtained.

<Performance Evaluation Method> Sensitivity and Gradation The clear sensitivity was evaluated according to the following method. A tablet for sensitivity measurement (No. 2 manufactured by Eastman Kodak Co., Ltd., a 21-step ferret scale with a density difference of 0.5) was closely attached to the photosensitive lithographic printing plate sample, and a 2 kW metal halide lamp (SPG-manufactured by Nippon Battery Co., Ltd.) was used. 1000) as the light source and 8.0
Exposure was performed under the conditions of mW / cm. Next, SDR-
1 (manufactured by Konica Corporation) was diluted 40 times with water using a developing solution (standard developing solution) and subjected to development processing at 25 ° C. for 40 seconds. After processing, the number of completely developed steps of the step tablet was defined as clear sensitivity.

For evaluation of the gradation, the value of the number of solid steps minus the number of clear steps was determined and evaluated according to the following evaluation criteria. The meanings of the symbols in Table 2 are as follows.

：: number of solid steps−number of clear steps ≦ 7.0 Δ: 7.0 <number of solid steps−number of clear steps ≦ 8.0 The number of clear steps refers to the number of steps of the step tablet that have been completely developed. The step number refers to the step number of the step tablet that has not been completely developed. The smaller the value of the number of solid steps-the number of clear steps, the better the gradation.

Under developing property and over developing property A positive type film containing a pattern is closely adhered to a photosensitive lithographic printing plate sample, and a 2 kW metal halide lamp (manufactured by Nihon Battery Co., Ltd.)
(PG-1000) as a light source under the condition of 8.0 mW / cm. Next, SDR-1 (Konica Corporation) was added to this sample.
(Standard developing solution), a developing solution diluted 12 times, 14 times and 16 times (under developing property) and a developing solution diluted 4 times and 6 times (over (Developability) at 25 ° C. for 40 seconds.
The sample surface after the treatment was visually observed and evaluated according to the following evaluation criteria. The meanings of the symbols in Table 2 are as follows.

Evaluation criteria for under-developability ：: The photosensitive layer in the non-image area was completely dissolved and removed. ：: The photosensitive layer in the non-image area was partially left. ×: The light in the non-image area was exposed. The layer is hardly dissolved.

Evaluation criteria for over-developability ○: No damage to image area ×: Film in image area is reduced.

Chemical resistance Ultra plate cleaner (UPC) used as a cleaning liquid for removing background stains generated in non-image areas during printing
(ABC Chemical Co., Ltd.). By immersing the printing plate on which the image is formed in the ultraplate cleaner at room temperature for a predetermined time (1 hour and 2 hours), washing with water, and comparing with the image portion before immersion,
The degree of erosion of the image portion with respect to the treatment chemical was determined.

Evaluation criteria for chemical resistance to treatment ○: No erosion of image area ：: Partial erosion of image area ×: Erosion of image area occurs entirely ○ △ is between ○ and △ The performance is shown.

Exposure Visibility The photosensitive lithographic printing plate sample was exposed to a metal halide lamp (manufactured by Nippon Battery Co., Ltd., SPG-1000) as a light source through a positive transparent original at 50 to 400 mJ / cm ^2, and the exposed portion and the unexposed portion were exposed. The optical density difference (ΔD) of the photosensitive layer in each part was measured using a Macbeth reflection densitometer.

The above results are shown in Table 2 below.

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[Table 2]

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According to the present invention, it is possible to provide a lithographic printing plate photosensitive composition having good sensitivity, under developability, over developability, chemical resistance, visible light exposure and gradation. .

Claims (4)

[Claims] 1. A lithographic printing plate photosensitive composition containing a quinonediazide compound and a novolak resin obtained by condensing a phenol containing phenol as an essential component with an aldehyde or a ketone. The weight average molecular weight in terms of polystyrene determined by a gel permeation chromatography (GPC) method as a standard is from 6,000 to 30,000, from 2,000 to 2,000.
GPC in the range of 5,000 and 150-1,000
The area value of the pattern is 30 to 9 with respect to the entire area.
A photosensitive composition for a lithographic printing plate comprising 0%, 0 to 40%, and 20 to 90%. 2. The photosensitive composition for a lithographic printing plate according to claim 1, wherein the novolak resin is a novolak resin obtained by combining at least two kinds having different weight average molecular weights. 3. The photosensitive composition for a lithographic printing plate according to claim 1, wherein the quinonediazide compound is a quinonediazidesulfonic acid ester of a novolak resin obtained by condensing phenols with aldehydes or ketones. 4. The photosensitive composition for a lithographic printing plate according to claim 3, wherein the quinonediazide compound has a weight average molecular weight of 2,000 to 5,000.