JPH04152345A - Photosensitive layer for planographic printing plate - Google Patents

Abstract

PURPOSE:To enhance printability and storage stability with time lapse by mixing a specified amount of specified compound. CONSTITUTION:The photosensitive layer containing an acrylic copolymer having hydroxy groups and carboxy groups, the organic acid salt of a diazo resin, and a dye, for forming the plano-graphic printing plate further contains the acid-photogenerating compound represented by formula I in an amount of 0.3-10wt.%. This compound is embodied by trichloromethyl phenylsulfonate, tribromophenylsulfonate, and trichloromethyl 2,4-dichlorophenylsulfonate. In the formula I, R is optionally substituted alkyl, such aryl, or a heterocyclic group, and each of X1-X3, is halogen, thus permitting a printed image to be sharp and storage stability to to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a photosensitive layer for lithographic printing plates, and more particularly to a photosensitive layer for lithographic printing plates with improved stability over time and printout properties.

b. Prior art Negative photosensitive lithographic printing in which a photosensitive composition whose main components are an acrylic copolymer having hydroxyl groups and carboxylic acid groups and a photosensitive diazo resin is coated on an aluminum support treated to make it hydrophilic. The edition is well known in the art. In this printing plate, by exposing the image to light, the exposed areas are cured and made insoluble in a developer, and the unexposed areas are dissolved and removed by the developer to form a lipophilic image area on the surface of the hydrophilic support. It is used for lithographic printing using water and ink.

The photosensitive diazo resin used in such lithographic printing plates is, in most cases, an organic acid salt of a condensate of an aromatic diazonium compound and a carbonyl-containing organic compound (
mainly aromatic sulfonates).

By mixing a dye having a salt-forming ability into the photosensitive layer containing such a diazo resin, print-out properties are imparted that allow images to be recognized immediately after exposure.

C1 Problems to be Solved by the Invention However, when the above-mentioned diazo resin is used, the print-out properties are poor. For this reason, in Japanese Patent Publication No. 39-17602 and Japanese Patent Application Laid-open No. 54-98613, halogenated Lewis acid salts of diazo resins (for example, hexate of a condensate of 4-diazodiphenylamine and formaldehyde) are used instead of organic acid salts of diazo resins. By using fluorophosphate, the bake-out property is improved.

However, when a halogenated Lewis acid salt of a diazo resin is used, a photosensitive lithographic printing plate having a photosensitive layer made of this and an acrylic copolymer having a hydroxyl group and a carboxylic acid group has poor stability over time.

That is, there are disadvantages in that developing defects occur over time and non-image areas are likely to become stained during printing.

In order to overcome this drawback, photoacid generating compounds have been proposed to replace the halogenated Lewis acid salts of diazo resins, such as JP-A Nos. 59-148784 and 63-2.
No. 61352 discloses an oxadiazole compound and a trihalomethyl compound, but no significant improvement was observed in printout properties.

Therefore, as a result of intensive research to improve these drawbacks, the inventors of the present invention discovered that, instead of using a photoacid-generating compound such as a halogenated Lewis acid salt of a diazo resin as a photosensitive diazo resin, an organic acid salt of a diazo resin was used. The inventors have discovered that a photosensitive layer having excellent print-out properties and stability over time can be obtained by mixing a specific photoacid-generating compound into a photosensitive layer containing .

d. Means for solving the problem, that is, the present invention, provides the following method in a photosensitive layer for a lithographic printing plate containing an acrylic copolymer having a hydroxyl group and a carboxylic acid group, an organic acid salt of a diazo resin, and a dye. The present invention provides a photosensitive layer for a lithographic printing plate, characterized in that the photoacid generating compound represented by (I) is mixed in an amount of 0.3 to 10% by weight.

- Shipura: (In the formula, R represents a substituted or unsubstituted alkyl group, aryl group, or heterocyclic compound residue, and X, , X, and x3 each represent a halogen atom) The above hydroxyl group and carboxylic acid The acrylic copolymer having a group can be produced by copolymerizing an addition polymerizable unsaturated compound having a hydroxyl group and an addition polymerizable unsaturated compound having a carboxylic acid group.

Examples of the addition polymerizable compound having a hydroxyl group include the following.

(1) Acrylates and methacrylates having hydroxyl groups, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and hydroxydodecyl, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, trimethylol Acrylates or methacrylates such as propanepentaerythritol, 2-hydroxy-3-phenoxypropyl, 2-hydroxy-3-methylphenoxyprovil.

(2) Acrylates and methacrylates of oligoesters having hydroxyl groups, such as polyester diols of succinic acid and propylene glycol, polyester diols of maleic acid and propylene glycol, polyester diols of phthalic acid and propylene glycol, hexahydrophthalic acid and propylene Acrylates and methacrylates such as polyester diols with glycols, polyester diols with tetrahydrophthalic acid and propylene glycol, polyester diols with tetrahydrophthalic acid and propylene glycol and glycerin-1-butyl ether.

(3) Acrylamide and methacrylamide having a hydroxyl group or derivatives thereof, such as acrylamide or methacrylamide such as hydroxyethyl, hydroxyphenyl, hydroxynaphthyl, N-hydroxyethyl-N-methyl.

Examples of addition-polymerizable unsaturated compounds having a carboxylic acid group include acrylic acid, methacrylic acid, mono(2-
Examples include methacryloxyethyl) hexahydrophthalate and mono(2-acryloxyethyl)hexahydrophthalate.

The above acrylic copolymer can also be copolymerized with other addition polymerizable unsaturated compounds.

As other addition-polymerizable unsaturated compounds, any unsaturated compounds can be used.

For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-amyl, n-hexyl, 2-ethylhexyl, octyl, lauryl, dodecyl, cyclohexyl, tetrahydrofuryl, benzyl, stearyl, dimethylaminoethyl, Examples include diethylaminoethyl, chloroethyl, aryl (eg, phenyl, tolyl, naphthyl, etc.), acrylic esters or methacrylic esters of glycidyl, or nitriles such as acrylonitrile and methacrylnitrile.

In the above acrylic copolymer, the content of the addition polymerizable unsaturated compound having a hydroxyl group is preferably 10 to 70% by weight, more preferably 20 to 60% by weight, based on the total amount of the acrylic copolymer. If it is less than 10% by weight, the adhesion to the aluminum support will be poor, and if it is more than 70% by weight, swelling of the image area during development is likely to occur.

In addition, the content of the addition polymerizable unsaturated compound having a carboxylic acid group is 2.0 to 4% based on the total amount of the acrylic copolymer.
It is preferably 0% by weight, more preferably 3.0 to 30% by weight. If it is less than 2.0% by weight, it will be difficult to dissolve in an alkaline aqueous developer solution, resulting in poor developability, and if it is more than 40% by weight, it will gel depending on the reaction conditions.

As the organic acid salt of the above-mentioned diazo resin, Japanese Patent Publication No. 40-86
No. 11, U.S. Patent No. 2922715, U.S. Patent No. 2946
Organic acid salts of condensates of diazodiarylamines and active carbonyl compounds such as formaldehyde and acetaldehyde, as described in No. 683, can be used.

Examples of the diazoarylamine include 4-diazodiphenylamine, 4-diazo-3-methyldiphenylamine, 4-diazo-3'-methyldiphenylamine, 4-diazo-3'-methyldiphenylamine,
Examples include -diazo-4'-methoxydiphenylamine and 4-diazo-3-methoxydiphenylamine.

Examples of compounds that form organic acid salts by reacting with the above condensates include Japanese Patent Publication No. 40-2203, Japanese Patent Publication No. 41-68
13, Japanese Patent Publication No. 47-1167, and the like.

Specifically, benzenesulfonic acid, p-1 luenesulfonic acid, 2,5-xylenesulfonic acid, linear or side chain dodecylbenzenesulfonic acid (commonly known as dodecylbenzenesulfone #), 2-methoxy-4-hydroxy- Examples include 5-benzoylbenzenesulfonic acid, methanyl yellow 2-chlorotoluene 4-sulfonic acid, and alkali metal salts, alkaline earth metal salts, and ammonium salts thereof.

The IsI salt of the diazo resin is preferably contained in an amount of 5 to 30% by weight based on the total weight of the photosensitive layer.

The dye used in the present invention is one that develops color from colorless to colored by the acid generated by exposure to light, one that fades from color to colorless, or one that changes hue.

Specific examples of such dyes include Victoria Pure Blue〇〇FI (manufactured by Hodogaya Chemical Co., Ltd.) and Oil Blue 16.
03 (manufactured by Orient Chemical Industries, Ltd.), Patent Pure Blue (manufactured by Sumitomo Mikuni Chemical Industries, Ltd.), Crystal Violet, Brilliant Green, Ethyl Bioleft, Methyl Violet, Methyl Green, Erythrosin B,
Triphenylmethane-based, diphenylmethane-based, represented by Pesic Tsuksin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4p-diethylamide, l-phenyliminonaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc. Examples include oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based, and anthraquinone-based dyes.

In the photosensitive layer of the present invention, a photoacid-generating compound represented by the general formula (I) is mixed.

Examples of the photoacid generating compound include trichloromethyl-phenylsulfone, tribromomethyl-phenylsulfone, trichloromethyl-p-chlorophenylsulfone, tribromomethyl-p-nitrophenylsulfone,
Trichloromethyl-p-nitrophenylsulfone, trichloromethyl-2,4-dichlorophenylsulfone, tribromomethyl-2,4-dichlorophenylsulfone,
2-Trichloromethylbenzothiazole sulfone, 46
-dimethylpyridine-2-tribromomethylsulfone,
Examples include 4,6-dimethyl-3-cyanopyridine-2-tribromomethylsulfone.

The above-mentioned photoacid-generating compound is mixed in an amount of 0.3 to 10% by weight based on the total weight of the photosensitive layer for a lithographic printing plate of the present invention. If the overlaying amount is less than 0.3%, an excellent printout effect cannot be obtained. On the other hand, if it is 10% by weight or more, an excellent bakeout effect is exhibited, but stiffness resistance is deteriorated.

Other lipophilic polymers or copolymers can also be added to the photosensitive layer of the present invention.

Examples include phenolic resins, substituted phenolic resins, polyhydroxystyrenes, halogenated polyhydroquinestyrenes, copolymers of hydroxystyrene and acrylic compounds, styrene-maleic anhydride copolymers, acrylic resins, modified acrylic copolymers. Examples include merging.

Furthermore, a preservative may be added to the photosensitive layer of the present invention.

Examples of preservatives include citric acid, tartaric acid, lactic acid, 5-
Examples include sulfosalicylic acid, oxalic acid, DL-malic acid, and 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid.

The content of these preservatives is preferably about 0.1 to 4.0% by weight, more preferably 0.5 to 3.0% by weight, based on the total weight of the photosensitive layer.

Furthermore, in order to improve the adhesion of the photosensitive layer or to obtain a uniform coating surface, a plasticizer or a surfactant may be added.

Examples of the plasticizer include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diethyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, diisononyl phthalate, ethyl phthalylethyl glycol, dimethyl Examples include isophthalate.

The content of the plasticizer is approximately 0 based on the total weight of the photosensitive layer.
．． 5 to 3.0% by weight, more preferably 0.6 to 2% by weight
．． It is in the range of 0% by weight.

As surfactants, sorbitan monooleate, sorbitan stearate, sorbitan monostearate,
Examples include sorbitan sekisuoleate, sorbitan monolaurate, polyoxyethylene nonylphenyl ether, and polyoxyethylene octylphenyl ether.

The content of the surfactant is about 0.4 to 2.0% by weight, more preferably 0.4 to 2.0% by weight, based on the total weight of the photosensitive layer.
It is 6-1.6% by weight.

When the photosensitive layer of the present invention is formed on a support, an acrylic copolymer, an organic acid salt of a diazo resin, a dye, a photoacid generating compound, and a preservative, a plasticizer, and a surfactant added as necessary. etc., by organic cutting, such as methanol, methylene chloride, ethyl acetate, tetrahydrofuran, N-N
-dimethylformamide, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
It is dissolved in one or more mixed solvents such as propylene glycol monomethyl ether, coated on a matrix support using various coating machines (e.g., Wheeler roll coater, bar coater, extrusion type coater, etc.), and dried. let

The support to which the photosensitive layer of the present invention is coated can be a plastic film, a metal plate made of copper, zinc, aluminum, stainless steel, etc., or a composite material combining two or more of these. In particular, aluminum plates that have been brushed or ball polished, aluminum plates that have been brush polished and then subjected to open oxidation treatment, aluminum plates that have been electrolytically polished and then anodized, or aluminum plates that have been treated with a combination of these. is preferred.

The pretreated aluminum plate is further subjected to chemical conversion treatment with alkali silicate, zirconium fluoride, alkyl titanate, trihydroxybenzoic acid, boehmite treatment, strontium acetate, zinc acetate, etc.
Coating treatment with an aqueous solution of magnesium acetate, calcium benzoate, etc. Coating treatment with polyvinylpyrrolidone, polyamine sulfonic acid, polyacrylic acid, polymethacrylic acid, poly-2-hydroxyethyl acrylate, etc. can also be carried out as a post-treatment.

An image can be obtained by exposing the photosensitive layer of the present invention coated on a support to actinic rays such as ultraviolet rays and developing it using an alkaline aqueous solution as a developer.

Examples of the alkaline aqueous fJ solution used as a developer include (1) sodium hydroxide, potassium hydroxide; (2)
Metal salts of weak acids, such as sodium salts, lithium salts, potassium salts, etc. of silicic acid, metasilicic acid, orthosilicic acid, phosphoric acid, birophosphoric acid, metaphosphoric acid, hexametaphosphoric acid, carbonic acid, tartaric acid, boric acid; (3 ) Ammonia and its derivatives, such as alkylamines (e.g. amine compounds such as monomethyl, dimethyl, trimethyl, monoethyl, diethyl, triethyl, etc.) or alkanolamines (e.g. monoethanolamine, jetanolamine, triethanolamine, diisopropylamine) Aqueous solutions of alkaline compounds such as amines);

An activator and/or a solvent can be added to the above alkaline aqueous solution. As the active agent, an anionic surfactant or an amphoteric surfactant can be used.

Examples of anionic surfactants include those having 8 to 22 carbon atoms.
Sulfuric esters of alcohols (e.g. polyoxyethylene alkyl sulfate soda salt), alkylaryl sulfonates (e.g. sodium dodecylbenzenesulfonate, polyoxyethylene dodecylphenyl sulfate soda, alkylnaphthalene sodium sulfonate, naphthalene sodium sulfonate, naphthalene) Formalin condensation of sodium sulfonate (1), sodium dialkyl sulfosaxonate, fatty acid amide sulfonate, alkyl phosphate, alkyl ether phosphate, etc. can be used.

Further, as the amphoteric surfactant, for example, an alkyl betaine type surfactant or an alkylimidacillin type surfactant can be used.

As the solvent, alcohols and ethers are preferable, but a solvent that does not dissolve 10% or more in water (20° C.) is most preferable. Examples of this type of solvent include alcohols such as benzyl alcohol, nc-α-phenylethyl alcohol, and 2-phenylethyl alcohol.
Examples of ethers include phenyl glycol and propylene glycol monobutyl ether.

The composition of the developer is 0.5 to 0.5% of the above alkaline compound.
10 wt%, surfactant 0-10 wt%, and solvent 0
Preferably, it contains up to 10% by weight.

The photosensitive layer of the present invention can also be used as a resist for fine processing or as a photosensitive layer for forming other images.

00 Effect The photosensitive layer for a lithographic printing plate of the present invention has a remarkable change in hue between the unexposed area and the exposed area, making it easier to recognize the image, and deterioration of the photosensitive layer over time is less than that of conventional ones.

f. Examples The present invention will be explained in more detail by Examples below, but the present invention is not limited thereto.

Examples 1-3. Comparative Example 1 A web-shaped aluminum plate (Material 1050) with a thickness of 0.24 m and a width of 1000 mm was degreased with alkali, and then the surface was polished with a nylon brush while applying a water suspension of vermiston, and then thoroughly washed with water.

Next, a 20% caustic soda solution was poured over the surface for 5 seconds at 70°C to etch 3 g/yet on the surface, and then washed with running water and treated with hydrochloric acid (35 g/l) and boric acid (20 g/l).
and aluminum ions (20 g/1) at 25° C. for 6 seconds at a current density of 25 A/d++”, followed by washing with water.

Next, the surface was etched by pouring a 20% caustic soda solution at 70°C, further washed with water, and then heated at 30°C.
2. Perform anodizing treatment in a 10% sulfuric acid aqueous solution.
An oxide film of 0 g/s' was formed.

Next, after washing with water, it was immersed in an aqueous solution containing 5% sodium silicate No. JTSa at 70°C for 10 seconds, and then washed with water and dried. A photosensitive solution having the composition shown below was applied to the aluminum plate thus obtained so that the dry coating weight was 1.8 g/m'', and it was dried at 100°C for 1 minute to obtain a photosensitive lithographic printing plate. Ta.

5 JL Enjiri 22 and acrylic copolymer (1) Diazo-based photosensitive side (1) (2-methoxy-4-hydroxy-5-benzoylbenzene sulfonate of a condensate of 4-diazodiphenylamine and formaldehyde) General Compound represented by formula (1) Victoria Pure Blue 80H (manufactured by Hodogaya Chemical Industry ■) 3.0g 0.3g χ g 0.1g Tartaric acid 0.03g Propylene glycol monomethyl ether 45g Ethylene glycol monomethyl ether
45gN-N-dimethylformamide
10g of the above acrylic copolymer (1) was produced as follows.

Under a nitrogen stream, dimethylformamide 1 was used as the reaction solvent.
0.3 g of azobisisobutyronitrile was added to 50 g, heated to 80 to 85° C., and a mixture having the following composition was dropped therein while stirring.

2-Hydroxyethyl methacrylate 4-hydroxyphenyl methacrylamide Methyl methacrylate Mono(2-methacryloxyethyl) hexahydrophthalate 0 g 0 g 5 g 5 g Acrylic nitrile 0 g After the dropwise addition, stirring was continued for 5 hours, and 150 g of dimethylformamide was added. Thereafter, it was poured into water to precipitate the copolymer. The precipitate was redissolved in 2-methoxyethanol, purified by dropping it into water, and vacuum-dried (70"C).
) to obtain an acrylic copolymer (1).

The weight average molecular weight of this copolymer was measured by gel vermi- nation chromatography (GPC), and was approximately 1.
It was 02.000.

The resulting photosensitive lithographic printing plate was exposed to light for 30 seconds at a distance of 1 - with a 2KW high-pressure mercury lamp, and the surface reflectance of the photosensitive layer in the exposed and unexposed areas was measured using Murakami Color Technology Research Fracture CM-53P. did. The results are shown in Table-1.

In Comparative Example 1, a comparative photosensitive liquid to which the compound (1) of Funagura (1) was not added was used.

As is clear from the results shown in Table 1, by adding the compound represented by the general formula (1) to the photosensitive liquid, the difference ΔR in reflectance increases and the image becomes clearer.

Example 4. Comparative Example 2 The following photosensitive liquid 4 or comparative photosensitive liquid 2 was applied to the aluminum plate used in Examples 1 to 3 at a dry coating weight of 1.8 g/■2, and dried at 100 ''C for 1 minute. Let me,
A photosensitive lithographic printing plate was obtained.

Note 1-[j:( Acrylic copolymer (1) 3.0g Diazo photosensitizer (1) (2-methoxy-4-hydro-5-benzoylbenzenesulfonic acid, a condensate of 4-diazodiphenylamine and formaldehyde) Salt) 0.3g Trichloromethyl-phenylsulfone 0.1g Victoria Pure Blue Bol+ (manufactured by Hodogaya Chemical Industry ■)
0.1g tartaric acid
0.03 g Propylene glycol monomethyl ether 45 g Ethylene glycol monomethyl ether
45gN-N-dimethylformamide
10g Top-71ELj:L Acrylic copolymer (113, (1g Diazo-based photosensitive 1(2) (hexafluorophosphate of condensate of 4-diazodiphenylamine and formaldehyde) 0.3g Victoria vinyl blue BOB (preserved) Tsuchiya Chemical Industry■
(manufactured by) 0.1g tartar stone M1
0.03g Propylene glycol monomethyl ether 45g Ethylene glycol monomethyl ether
45gN-N-dimethylformamide
10g of the photosensitive lithographic printing plate obtained as in Example 1 was exposed to light for 30 seconds using a high-pressure mercury lamp at a distance of 1-1, and the surface reflectance of the photosensitive layer in the exposed and unexposed areas was measured as shown in Example 1- Measurement was carried out in the same manner as in 3. The results are shown in Table-2.

In addition, these photosensitive lithographic printing plates were heated at high temperatures (35
℃, 80%) for several days, exposed as above, developed with the following developer at 25℃ for 30 seconds, washed with water, made fat-free with gum arabic solution, and then applied to a printing machine to remove stains. I checked to see if it existed. The number of days left until staining (preservability) is shown in Table 2. It can be said that the longer the number of days left, the more excellent the photosensitive printing plate is in terms of stability over time.

3U/UL group" Good potassium silicate 20% aqueous solution 50g Phenyl glycol PCI+ (manufactured by Nippon Nyukazai ■) 40g Potassium isopropyl naphthalene disulfonate g Potassium sulfite g Water 03g As is clear from the results shown in Table 2, Example 4 The photosensitive layer for a lithographic printing plate had a larger difference ΔR in reflectance between the unexposed area and the exposed area than the photosensitive layer of Comparative Example 2, which used a halogenated Lewis acid salt of a diazo resin as a photosensitizer, and the printed image was clear. It is. It also has excellent stability over time.

f. Effects of the Invention According to the present invention, a photosensitive layer for a lithographic printing plate with a clear printed image and excellent stability over time can be obtained.

Patent applicant: Okamoto Chemical Industry Co., Ltd. (4 idiots)

Claims (1)

[Claims] (1) A photoacid-generating compound represented by the following general formula (I) is added to the photosensitive layer for a lithographic printing plate containing an acrylic copolymer having a hydroxyl group and a carboxylic acid group, an organic acid salt of a diazo resin, and a dye. A photosensitive layer for a lithographic printing plate, characterized in that it contains a mixture of 3 to 10% by weight. General formula: R-SO_2-C▲There are mathematical formulas, chemical formulas, tables, etc.▼(
I) (In the formula, R represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic compound residue, and X_1, X_2 and X_3 each represent a halogen atom.)