JPH01102456A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To improve developability by an alkaline developing soln. and to decrease the remaining of diazo by using a co-condensation compd. contg. an arom. diazonium compd. as a constituting unit. CONSTITUTION:The co-condensation compd. (C) contg. an arom. compd. (A) having a phenolic hydroxyl group and the arom. diazonium compd. (B) as the constituting unit is compounded with the title compsn. The compd. C is obtd. by dissolving the component A (e.g. pyrogallol) and the component B (e.g. 4- diazodiphenyl amine sulfate) in, for example, sulfuric acid, and subjecting the soln. to polycondensation under addition of aldehydes thereto. A lipophilic oily high-polymer compd. to serve as the binder of the compd. C and a dye for obtaining visible images, etc., may be incorporated into the compd. A photosensitive planographic printing plate is obtd. if the above-mentioned compsn. is applied on an Al sheet or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photosensitive composition, and particularly to a photosensitive composition suitable for manufacturing a photosensitive lithographic printing plate. .

[Background of the invention]

Photosensitive printing plates are generally produced by coating a photosensitive composition on a support such as an aluminum plate, irradiating it with active light such as ultraviolet rays through a negative image, polymerizing or crosslinking the irradiated areas, and turning the composition into a developer. Insolubilize and elute non-light irradiated areas into a developer, making each area an image area that repels water and receives oil-based ink, and a non-image area that receives water and receives oil-based ink. It is obtained by

As the photosensitive composition in this case, diazo resins such as a condensate of p-diazodiphenylamine and formaldehyde have been widely used.

However, since conventionally known diazo resins do not have alkali solubility in -a, when a photosensitive composition containing the resin is developed with an alkaline developer after exposure, the developability, especially Developability under under conditions is not good, and the diazo resin remains in the form of a film on the surface of the support after development, resulting in a so-called diazo residue, resulting in a decrease in printability.

Therefore, the main object of the present invention is to provide a lipophilic polymer compound (
The object of the present invention is to provide a novel photosensitive composition that can expand the selection range of binder resins.

[Means for solving problems]

The above object is achieved by containing a co-condensed compound containing an aromatic compound having a phenolic hydroxyl group and an aromatic diazonium compound as constitutional units.

[Specific structure of the invention]

The present invention will be explained in more detail below.

The aromatic compound having a phenolic hydroxyl group according to the present invention contains an aromatic ring having at least one phenolic hydroxyl group in the molecule, and this aromatic ring is preferably an aryl group, such as a phenyl group. In the present invention, the number of phenolic hydroxyl groups bonded to one aromatic ring is not particularly limited; It is necessary that the aryl group has at least two unsubstituted sites on the aromatic ring.

Examples of aromatic compounds having a phenolic hydroxyl group in the molecule used in this invention include phenol,
(o, m, p) cresol, xylenol, resorcin, 2-methylresorcin, (o, ml p) methoxyphenol, m-ethoxyphenol, catechol, phloroglycine, p-hydroxyethylphenol, naphthol, pyrogallol, hydroquinone, p -Hydroxybenzyl alcohol, 4-chlororesorcinol, biphenyl-4,4'-diol, 1.2.4-benzenetriol, bisphenol A, 2.4-dihydroxybenzophenone, 2,3.4-trihydroxybenzophenone, p- Examples include hydroxyacetophenone, 4.4-dihydroxydiphenyl ether, 4.4'-dihydroxydiphenylamine, 4.4'-dihydroxydiphenyl sulfone, 4.4'-dihydroxydiphenyl sulfide, cumylphenol, etc. Particularly preferred among these are , p-cresol, resorcin, 2-methylresorcin, pyrogallol, p-methoxyphenol, 4.4
'-dihydroxydiphenyl ether, 4.4'-dihydroxydiphenylamine, and 2.3.4-1-dihydroxybenzophenone.

The aromatic diazo compound used in the present invention is not particularly limited as long as it has a diazonium group directly bonded to the aromatic ring, but examples thereof include 4-diazodiphenylamine sulfate, 4-diazodiphenylamine sulfate, Diazodiphenylamine tetrafluoroborate, 4-diazodiphenylamine hexafluorophosphate, 4-morpholino-benzenediazonium tetrafluoroborate, 4-(N-ethyl-N-hydroxyethyl)-aminobenzenediazonium sulfate salt, 4-
N,N'-dimethylaminobenzenediazonium hexafluorophosphate, and 8-hydroxy-2-naphthalenediazonium tetrafluoroborate. Among these, particularly preferred aromatic diazo compounds include 4-diazodiphenylamine salts.

The photosensitive diazo cocondensation resin according to the present invention can be prepared by a known method,
For example, Photographic Science and Engineering Link (Photo, Sci.

Eng.) Vol. 17, p. 33 (1973), U.S. Patent No. 2.063.631, U.S. Patent No. 2.679.498. It can be obtained by polycondensing salts, aromatic compounds having a phenolic hydroxyl group, and aldehydes such as paraformaldehyde, acetaldehyde, benzaldehyde, or ketones such as acetone and acetophenone.

Furthermore, these aromatic compounds, aromatic diazo compounds, and aldehydes or ketones having a phenolic hydroxyl group in their molecules can be freely combined with each other, and it is also possible to mix two or more of each and co-condense them. . Furthermore, co-condensation can be carried out by adding a co-condensable phenol having no carboxyl group.

At that time, the molar ratio of the aromatic compound having a phenolic hydroxyl group and the aromatic diazo compound was 1:0.
1 to 0.1:1; preferably t:O,S to 0.2:1,
More preferably, the ratio is 1:1 to 0.2:1. In this case, the molar ratio of the total of the compound having a phenolic hydroxyl group and the aromatic diazo compound to the aldehyde or ketone is usually 1:0.6 to 1:2, preferably 1:
Prepare at a ratio of 0.7 to 1:1.5 and cook at low temperature for a short time, e.g.
A diazo cocondensation resin is obtained by reacting for about a period of time.

The counter anion of the diazo resin used in the present invention is
It contains an anion that forms a stable salt with the diazo resin and makes the resin soluble in organic solvents.

These include organic carboxylic acids such as decanoic acid and benzoic acid, organic phosphoric acids such as phenylphosphoric acid, and sulfonic acids; typical examples include methanesulfonic acid, chloroethanesulfonic acid, dodecanesulfonic acid, benzenesulfonic acid. , toluenesulfonic acid, mesitylenesulfonic acid, and anthraquinonesulfonic acid, 2-hydroxy-4-
Aliphatic and aromatic sulfonic acids such as methoxybenzophenone-5-sulfonic acid, hydroxysulfonic acid, 4-acetylbenzenesulfonic acid, dimethyl-5-sulfone isophthalate, 2.2', 4.4'-tetrahydroxybenzophenone, Hydroxyl group-containing aromatic compounds such as 1,2.3-trihydroxybenzophenone and 2.2',4-)dihydroxybenzophenone, halogenated Lewis acids such as hexafluorophosphoric acid and tetrafluoroboric acid, and peroxidases such as ClOa and IQs. Examples include, but are not limited to, halogen acids, and among these, particularly preferred are hexafluorophosphoric acid and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid.

Examples of condensation resins (diazo cocondensation resins) with aldehydes or ketones that contain aromatic compounds having a phenolic hydroxyl group and aromatic diazo compounds as constituent units used in the present invention include p-cresol. -4-Diazodiphenylamine/tetrafluoroborate-formaldehyde resin, resorcinol-4-diazodiphenylamine/hexafluorophosphate-formaldehyde resin, 2-methylresorcin-4-diazodiphenylamine/hexafluorophosphate- Formaldehyde resin, p-methoxyphenol-4-diazodiphenylamine/2-hydroxy-
4-methoxybenzophenone-5-sulfonate-acetaldehyde resin, pyrogallol-4-diazodiphenylamine hexafluorophosphate-formaldehyde resin,
Phloroglycin-4-diazodiphenylamine/tetrafluoroborate-acetone resin, 4,4'-dihydroxydiphenyl ether-4-diazodiphenylamine/hexafluorosulfate-acetate aldehyde resin, p-hydroxyethylphenol- 4-Diazodiphenylamine/hexafluorophosphate-benzaldehyde resin, 2,4-dihydroxybenzophenone-4-diazodiphenylamine/
Hexafluorophosphate-formaldehyde resin, 4.4'-
Dihydroxydiphenylamine-4-diazodiphenylamine/hexafluorophosphate-formaldehyde resin, etc., and among these, particularly preferred are resorcin-4-diazodiphenylamine/hexafluorophosphate-formaldehyde resin, 2-methylresorcin-4 -Diazophenylamine/hexafluorophosphate -Formaldehyde resin, pyrogallol-4-diazodiphenylamine/hexafluorophosphate -Formaldehyde resin, 2,4-dihydroxybenzophenone-4-diazodiphenylamine/hexafluorophosphate - formaldehyde resin.

The diazo cocondensation resin of the present invention can have any molecular weight by varying the molar ratio of each monomer and the condensation conditions, but it can be effectively used for the purpose of the present invention. Therefore, the molecular weight is about 400 to t.
o, ooo can be used, but preferably about 800 to 5,000.

The photosensitive diazo cocondensation resin described above is preferably used in combination with a water-insoluble and alkali-soluble or lubricating lipophilic polymer compound as a binder resin.

As this lipophilic polymer compound, the following (1) to (2) are used.
Examples include copolymers whose structural units are the monomers shown below and which usually have a molecular weight of 20,000 to 200,000.

(1) Acrylamides, methacrylamides, acrylic esters, and methacrylic esters having an aromatic hydroxyl group, such as N-(4-hydroxyphenyl) alkylamide or N-(4-hydroxyphenyl) methacrylamide, 0-1m -1p-hydroxystyrene, 0-1m-1p-hydroxyphenyl acrylate or methacrylate, ゛(2) Acrylic esters having aliphatic hydroxyl groups, and methacrylic esters, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, (4) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, acrylic acid hexyl, octyl acrylate, acrylic acid-
(Substituted) alkyl acrylates such as 2-chloroethyl, glycidyl acrylate, N-dimethylaminoethyl acrylate, (5) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 4-hydroxybutyl methacrylate,
(Substituted) alkyl methacrylates such as glycidyl methacrylate and N-dimethylaminoethyl methacrylate; (6) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N- Cyclohexyl acrylamide, N-
Acrylamides or methacrylamides such as hydroxyethyl acrylamide, N-phenylacrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenylacrylamide, (η ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl Vinyl ethers such as vinyl ether, octyl vinyl ether, and phenyl vinyl ether; (8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate; (9) Styrene, α-methylstyrene, methylstyrene, and chloromethyl. Styrenes such as styrene, (II Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, αD Olefins such as ethylene, propylene, isobutylene, butadiene, isoprene, etc., 02 N-vinylpyrrolidone, N -Vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylatetrile, etc. Furthermore, monomers that can be copolymerized with the above monomers may be copolymerized.Also, copolymers obtained by copolymerization of the above monomers may be used, for example, with glycidyl It also includes, but is not limited to, those modified with methacrylate, glycidyl acrylate, etc.

More specifically, it contains the monomers listed in (1) and (2) above. A copolymer having a hydroxyl group is preferable,
More preferred are copolymers having aromatic hydroxyl groups.

The copolymer preferably contains an α,β-unsaturated carboxylic acid listed in (3), and the copolymer preferably has an acid value of 10 to 100.

The preferred molecular weight of the above copolymer is 40,000 to 150,000.

Further, polyvinyl butyral resin, polyurethane resin, polyamide resin, epoxy resin, novolac resin, natural resin, etc. may be added to the above copolymer as necessary.

The lipophilic polymer compound used in the present invention is usually 40 to 99% by weight, preferably 50 to 99% by weight in the solid content of the photosensitive composition.
Contains 95% by weight. In addition, the photosensitive diazo resin used in the present invention is usually 1 to 60% by weight, preferably 3 to 3% by weight.
Contains 0% by weight.

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

As the dye, one that changes color tone by reacting with free radicals or acids can be preferably used.

Here, "the color tone changes" includes both a change from colorless to a colored tone, and a change from a color to colorless or a different colored tone. Preferred dyes are those that change color tone by forming salts with acids.

For example, Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.), Oil Blue #603 (manufactured by Orient Chemical Industry Co., Ltd.), Patent Pure Blue (manufactured by Sumitomo Mikuni Chemical Co., Ltd.), Crystal Violet, Brilliant Green, Ethyl Bioleft, Methyl Bioleft , methyl green, erythrosin B1 basic tsuksin, malachite green, oil red, m-cresol purple, rhodamine B1 auramine, 4-p-diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenyl acetanilide, etc. , diphenylmethane type, oxazine type, xanthine type,
Iminonaphthoquinone-based, azomethine-based, or anthraquinone-based dyes are examples of color-changing agents that change color from colored to colorless or to a different colored tone.

On the other hand, examples of color changing agents that change from colorless to colored include leuco dyes, triphenylamine, diphenylamine, 0-chloroaniline, 1.2.3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis -dimethylaminodiphenylamine,
1.2-dianilinoethylene, p, p', p'-)lis-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p',
p'-) riamino-〇-methyltriphenylmethane, p
, p'-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane, and p, p', p"-triaminotriphenylmethane. .

Particularly preferred are triphenylmethane-based and diphenylmethane-based dyes, more preferably triphenylmethane-based dyes, and especially Victoria Vinia Blue BOH.

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

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

For example, alkyl ethers (
(e.g., ethyl cellulose, methyl cellulose), fluorine-based surfactants, nonionic surfactants (e.g., Pluronic L-64 (manufactured by Asahi Denka Corporation)), plasticizers for imparting flexibility and abrasion resistance to coating films. agents (e.g. butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate,
tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers and polymers of acrylic acid or methacrylic acid), fat-sensitizing agents for improving the fat-sensitivity of image areas (for example, JP-A-55-527) half-esterified styrene-maleic anhydride copolymer with alcohol, etc.), stabilizers [e.g., phosphoric acid, phosphorous acid, organic acids (citric acid, chelic acid, benzenesulfonic acid, naphthalenesulfonic acid, 4- Methoxy
2-hydroxybenzophenone-5-sulfonic acid, tartaric acid, etc.)]. The amount of these additives added varies depending on the purpose of use, but is generally 0.01 to 30% by weight based on the total solid content.

When such a photosensitive composition is applied to the production of a photosensitive lithographic printing plate, it is coated on a suitable support.

The support used in the photosensitive lithographic printing plate is as follows:
Paper, plastics (e.g. polyethylene, polypropylene, polystyrene, etc.) laminated paper, plates of metals such as aluminum (including aluminum alloys), zinc, copper, etc., cellulose diacetate, cellulose triacetate, cellulose propionate, polyethylene terephthalate, Plastic films such as polyethylene, polypropylene, polycarbonate polyvinyl acecool, etc., plastic films laminated or vapor-deposited with metals such as those mentioned above, steel plates plated with aluminum or chrome, etc., and among these, in particular, Aluminum and aluminum-coated composite supports are preferred.

Further, the surface of the aluminum material is preferably roughened for the purpose of increasing water retention and improving adhesion with the photosensitive layer.

Examples of the surface roughening method include generally known methods such as brush polishing, ball polishing, electrolytic etching, chemical elastomer lamp, liquid honing, sandblasting, etc., and combinations thereof, preferably brush polishing and electrolytic etching. , chemical etching and liquid honing. Among these, a surface roughening method including the use of electrolytic etching is particularly preferred. Also, as the electrolytic bath used during electrolytic etching, acids, alkalis or their An aqueous solution containing a salt or an aqueous solution containing an organic solvent is used, and among these, an electrolytic solution containing hydrochloric acid, nitric acid, or a salt thereof is particularly preferred. Further, the roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary. It is desirable that the aluminum plate thus obtained is subjected to anodizing treatment, and particularly preferred is a method of treatment in a bath containing sulfuric acid or phosphoric acid. Further, if necessary, a sealing treatment using an alkali silicate or hot water, and a surface treatment such as immersion in a water-soluble polymer compound or an aqueous potassium fluorozirconate solution can be performed.

To provide the above photosensitive composition on a support, predetermined amounts of a photosensitive diazo cocondensation resin, a lipophilic polymer compound, and, if necessary, various additives are added to a suitable solvent (methyl cellosolve, ethyl cellosolve). , methyl cellosolve acetate, acetone, methyl ethyl ketone, methanol, dimethyl formamide, dimethyl sulfoxide, water, or a mixture thereof, etc.) to prepare a coating solution of the photosensitive composition, and apply this onto a support and dry it. It is desirable that the concentration of the photosensitive composition during coating is in the range of 1 to 50 glcd. In this case, the amount of photosensitive composition applied may be approximately 0.2 to 10 glcd. .

A conventional method is applied to coat the photosensitive material on the support. That is, by exposing a transparent original image having a line image, a halftone image, etc. to light, and then developing it with an aqueous developer, a negative relief image can be obtained with respect to the original image. Examples of active light sources suitable for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, and the like.

The developer used for developing the photosensitive composition according to the present invention contains a specific organic solvent, an alkaline agent, and water as essential components. The specific organic solvent herein refers to the non-exposed area (
An organic solvent that can dissolve or swell the non-image area (non-image area) and has a solubility in water of 10% by weight or less at room temperature (20°C), and has the above characteristics. Examples include ethyl acetate, propyl acetate, butyl acetate, amine acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate. , carboxylic acid esters such as butyl levulinate; ketones such as ethyl butyl ketone, methyl isobutyl ketone, and cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, benzyl alcohol, methylphenyl carbinol, Alcohols such as n-amyl alcohol and methyl amyl alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride, and monochlorobenzene. One or more of these organic solvents may be used, and among these organic solvents, ethylene glycol monophenyl ether and benzyl alcohol are particularly effective. The content of these organic solvents in the developer is generally 1 to 20% by weight, particularly 2 to 1% by weight.
More preferable results are obtained when the amount is 0% by weight.

On the other hand, the alkaline agents contained as essential components in the developer include (A) sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium dibasic or tertiary phosphate, or Inorganic alkaline agents such as ammonium salts, sodium metasilicate, sodium carbonate, ammonia, etc. (B) Mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or diisopropylamine, n-
Examples include organic amine compounds such as butylamine, mono-, di-, or triethanolamine, mono-, di-, or triisopropanolamine, ethyleneimine, and ethylenediamine.

The content of these alkaline agents in the developer is usually 0.
05 to 4% by weight, preferably 0.5 to 2% by weight.

In addition, in order to further improve storage stability, rigidity resistance, etc., it is preferable to include a water-soluble sulfite in the developer. Such water-soluble sulfites include alkali or alkaline earth sulfites. Metal salts are preferred, such as sodium sulfite, potassium sulfite, lithium sulfite, magnesium sulfite, and the like. The content of these sulfites in the developer composition is usually 0.05 to 4% by weight, preferably 0.1 to 1% by weight.

If such a developer is brought into contact with the photosensitive composition after imagewise exposure or is rubbed with the developer, the exposed areas of the photosensitive composition layer will be removed after 10 to 60 seconds at room temperature to 40°C. The photosensitive composition in non-exposed areas is completely removed without adversely affecting the surface of the photosensitive lithographic printing plate, for example, resulting in a photosensitive lithographic printing plate.

Next, a typical synthesis example of the diazo cocondensation resin according to the present invention will be shown.

(Synthesis Example 1) Pyrogallol (0,025 mol) and 22.0 g (0,075 r-ole) of 4-diazodiphenylamine sulfate were dissolved in 90 g of concentrated sulfuric acid under water cooling. After this reaction, 2.7 g of paraformaldehyde (0.09 mol) were added slowly. At this time, the addition was carried out so that the reaction temperature did not exceed 10°C. Thereafter, stirring was continued for 2 hours under water cooling. This reaction mixture was poured into 1 liter of ethanol under ice cooling, and the resulting precipitate was filtered. After washing with ethanol, this precipitate was dissolved in 20 (ld) pure water, and this solution was diluted with 1
A cold concentrated aqueous solution of 0.5 g of zinc chloride was added. The resulting precipitate was filtered, washed with ethanol, and dissolved in 300-pure water. To this liquid was added a cold concentrated aqueous solution in which 13.7 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was filtered and washed with water, and then heated at 30°C for 1
Diazo cocondensation resin-1 was obtained by drying day and night.

When the molecular weight of this diazo cocondensation resin-1 was measured by GPC, it was found to be about 2100 in weight average molecular weight.

Regarding the other diazo cocondensation resins mentioned above, Synthesis Example 1
It can be synthesized by the same method as .

Next, a synthesis example of the lipophilic polymer compound according to the present invention will be shown.

(Synthesis of lipophilic polymer compound 1) N-(4-hydroxyphenyl)methacryamide lo,
Og, acrylonitrile 25g, ethyl acrylate) 6
0 g, 5 g of methacrylic acid, and 1.642 g of azobisisobutyronitrile were dissolved in a 1:1 acetone-methanol mixed solution 1) 2-, and the mixture was purged with nitrogen and then heated at 60° C. for 8 hours.

After the reaction was completed, the reaction solution was poured into 5 l of water with stirring, and the white precipitate was filtered and dried to obtain 90 l of the lipophilic polymer compound.
I got g.

When the molecular weight of this lipophilic polymer compound 1 was measured by gel permini-silane chromatography (hereinafter abbreviated as GPC), the weight average molecular weight was 85,000.

(Synthesis of lipophilic polymer 2) 2-hydroxyethyl methacrylate) 50.0 g.

Acrylonitrile 20g 1 Methyl methacrylate 25g
1 A mixture of 5 g of methacrylic acid and 1.2 g of benzoyl peroxide was added dropwise to 300 g of ethylene glycol monomethyl ether heated to 100°C over 2 hours.
and 0.3 g of penzoyl peroxide were added thereto, and the mixture was allowed to react for 4 hours. After the reaction was completed, the mixture was diluted with methanol and poured into water 51 with stirring, and the resulting white precipitate was collected by filtration and dried to obtain 90 g of lipophilic polymer compound 2.

When the molecular weight of this lipophilic polymer compound was measured by GPC, the weight average molecular weight was 65,000.

(Synthesis of lipophilic polymer compound 3) 2-hydroxyethyl methacrylate) 45 g.

Acrylonitrile 10g 1 Ethyl methacrylate 35g
A mixed solution of 10 g of methacrylic acid and 1.2 g of benzoyl peroxide was added dropwise to ethylene glycol monomethyl ether in the same manner as in the synthesis of lipophilic polymer compound 2 to obtain 90 g of lipophilic polymer 3.

When the molecular weight of this lipophilic polymer compound was measured by GPC, the weight average molecular weight was 62,000.

〔Example〕

(Example 1) An aluminum plate was degreased with a 3% aqueous sodium hydroxide solution, electrolytically etched in a 2% hydrochloric acid bath at 25°C and at a current density of 3 A/ds, and after washing with water, it was etched in a 30% sulfuric acid bath. 30
Anodizing was carried out for 2 minutes at 1.5 A/d at 1.5 A/d. Next, a 1% aqueous sodium metasilicate solution was sealed at 85° C. for 30 seconds, washed with water, and dried to obtain an aluminum plate for lithographic printing.

A photosensitive liquid having the following composition was applied to this aluminum plate so that the film weight after drying was 1.5 g/rd.

Photosensitive liquid-1 Lipophilic polymer compound-15.0g Diazo cocondensation resin-1 (Synthesis example 1) 0.5g Methyl cellosolve 100+nff1 The obtained photosensitive planographic printing plate was brought into close contact with a negative transparent original image, and 2- The film was exposed to light for 30 seconds from a distance of 60 cm using a metal halide lamp, and developed for 40 seconds at 25° C. using developer-1 having the following composition.

Composition of developer-1 Benzyl alcohol 30m Sodium carbonate 5g Sodium sulfite
5g Sodium dodecylbenzenesulfonate 10g Water
1) Next, prepare a diluted developer (developer-2) in which an equal volume of pure water is added to developer-1 and a diluted developer (developer-3) in which twice the amount of pure water is added, When development was carried out in the same manner as above, good printing plates were obtained in all cases without developing defects (stains) in non-image areas. Next, in order to examine the diazo residue in the non-image area, half of the non-image area of the printing plate obtained in this way was exposed again and compared with the area that was not re-exposed, and it was not visually distinguishable. Furthermore, when the above-mentioned photosensitive lithographic printing plate was forcibly stored (55°C, concentration 0%RH, 3 days) and plate-making was carried out in the same manner as above, no staining occurred with either developer. , a good printing plate could be obtained.

When the printing plate obtained as described above was printed on an offset printing machine, a large number of prints with sharp and high contrast images were obtained.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that the diazo cocondensation resin-1 in the photosensitive liquid-1 in Example 1 was replaced with the following diazo resin-1. Diazo resin-1 was prepared in the same manner as in Synthesis Example 1, except that p-hydroxybenzoic acid was omitted and 29.3 g (0.1 mol) of 4-diazodiphenylamine sulfate was used as the raw material. Obtained. The molecular weight of the obtained 4-diazodiphenylamine/hexafluorophosphate-formaldehyde resin was measured by GPC, and the weight average molecular weight was about 2,300.

As a result, when developed using developer-3, stains occurred in the non-image areas of the printing plate. In addition, with respect to the photosensitive lithographic printing plates that were forcibly stored, stains occurred in the non-image areas in the case of Developer Solution-2 and Developer Solution-3.

On the other hand, regarding the diazo residue in the non-image area, when half of the non-image area of the printing plate that was well developed using developer-1 was re-exposed and compared with the area that was not re-exposed, it was visually observed. Diazo residue was clearly observed in areas that were not re-exposed.

(Example 2) A photosensitive liquid having the following composition was applied to the same aluminum plate as in Example 1 so that the film weight after drying was 1.7 g/m.

Photosensitive liquid-2 Lipophilic polymer compound-25.0g Jurimer MCIOL (manufactured by Nippon Shiyaku) 0.3
g Methyl cellosolve 100 - The resulting photosensitive lithographic printing plate was exposed for 40 seconds under the same conditions as in Example 1, and then developed with the same developer 1 to 3 as used in Example 1 at 30°C and 20°C. When developing for a second, a good printing plate with no stains in the non-image area was obtained in all cases. Next, the diazo residue in the non-image area was examined in the same manner as in Example 1. I couldn't observe it. Furthermore, when the photosensitive lithographic printing plates that had been forcibly stored were developed, no stains were observed and the printing results were good.

(Example 3) After forming primary grains on a degreased aluminum plate by liquid honing using 400 mesh pumice stone-water suspension, the surface was lightly etched with 10% sodium hydroxide, and % nitric acid bath at 30 °C, IO
Secondary grains were formed by electrolytic etching at a current density of A/dm''. Next, anodizing and sealing were performed in the same manner as in Example 1 to obtain an aluminum plate for lithographic printing plate.

A photosensitive liquid having the following composition was applied to this aluminum plate so that the film weight after drying was 1.5 g/rrr.

Photosensitive solution-3 Lipophilic polymer compound-35.0 g Methyl cellosolve 100 m The obtained photosensitive lithographic printing plate was exposed for 40 seconds under the same conditions as in Example 1, and the same developer as used in Example 1 was used. -1 to 3 were developed at 30°C for 20 seconds, and a good printing plate with no stains in the non-image area was obtained in all cases.
Next, when the diazo residue in the non-image area was examined in the same manner as in Example 1, it could not be visually observed. Furthermore, when the photosensitive lithographic printing plates that had been forcibly stored were developed, no stains were observed and the printing results were good.

〔Effect of the invention〕

As described above, according to the present invention, the developability is excellent and diazo residue can be prevented. 7

Claims (1)

[Claims] (1) A photosensitive composition comprising a co-condensation compound containing an aromatic compound having a phenolic hydroxyl group and an aromatic diazonium compound as constitutional units.