JPS62175734A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To enable development in an aqueous solution of alkali, to reduce print stains, and to enhance printing resistance by incorporating a diazo resin having specified repeating units. CONSTITUTION:A photosensitive composition enhanced in developability in an aqueous alkali developing solution and reduced in print stains can be obtained by incorporating a polyurethane resin having carboxylic groups and when needed, hydroxyl groups and/or nitrile groups, and the diazo resin having at least one of the repeating units each represented by formula (I), or at least one of the groups represented by formulae (I) and (II), and a number of the hydrogen atoms of a diazodiphenylamine structure as much as >=2.5 times that of a methylene or methine group connecting said structure. In said formula, each of R1-R3 is H, alkyl, or the like; X<-> is a naphthalenesulfonate anion; and Y<-> is the other organic sulfonate anion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive composition. More specifically, the present invention relates to a photosensitive composition that can be developed with an alkaline aqueous solution, has little printing stain, has high printing durability, and has strong images in highlighted areas, and is suitable for use in photosensitive lithographic printing plates.

[Conventional technology]

The majority of substances used as photosensitive substances in printing materials that have been given photosensitivity in advance are diazonium compounds, and the most commonly used ones are diazo resins represented by formaldehyde condensates of p-diazodiphenylamine. be.

The composition of the photosensitive layer of a photosensitive lithographic printing plate using a diazo resin may be a diazo resin alone, i.e. without a binder, as described, for example, in U.S. Pat. No. 2,714,066. For example, JP-A-50-3060
As described in Publication No. 4, it can be classified as a mixture of a binder and a diazo resin. In recent years, many photosensitive lithographic printing plates using diazonium compounds are made of a diazonium compound and a polymer as a binder in order to have high printing durability.

As described in JP-A No. 50-30604, such a photosensitive layer is of the so-called alkaline development type, in which the unexposed area is removed (developed) with an aqueous alkaline developer, and the so-called alkaline development type, in which the unexposed area is removed (developed) with an aqueous alkaline developer, and the photosensitive layer is developed with an organic solvent developer. So-called solvent-developed types that are removed are known. Among them, the alkaline developing type is attracting attention from the viewpoint of occupational safety and health, and this is mainly determined by the properties of the binder. A method for imparting alkaline developability to the binder is to copolymerize a carboxylic acid-containing monomer as described in JP-A-50-30604, or as described in U.S. Pat. No. 2,861,058. There is a method of introducing a carboxylic acid into a polymer by reacting a hydroxyl group of polyvinyl alcohol with a cyclic acid anhydride such as phthalic anhydride. However, the resulting polymer has poor abrasion resistance due to its structure, and only lithographic printing plates with low printing durability can be obtained from photosensitive lithographic printing plates containing such a binder in the photosensitive layer. On the other hand, polyvinyl acetal forms a tough film and has wear resistance, but has the disadvantage that only organic solvent-developable photosensitive lithographic printing plates can be obtained.

[Problem that the invention seeks to solve]

Polyurethane resins are also known as polymers with excellent abrasion resistance. and a combination system of a diazonium salt polycondensate and a branched polyurethane resin is disclosed. However, none of these polyurethane resins have an alkali-soluble group, so they inherently have insufficient solubility in aqueous alkaline developers, and it is extremely difficult to develop them without leaving a residual film. there were.

Furthermore, if a strong force is applied during development, the image in the highlighted area may be removed.

[Purpose of the invention]

An object of the present invention is to overcome the above-mentioned drawbacks, to provide a novel photosensitive composition that has excellent developability with an aqueous alkaline developer and causes less printing stains. Another object of the present invention is to provide a novel photosensitive composition suitable for producing a photosensitive lithographic printing plate having high printing durability and strong images in highlighted areas.

[Means for solving problems]

The present inventors have made extensive studies to achieve the above objects, and as a result, have discovered that these objects can be achieved by using a novel photosensitive composition, and have arrived at the present invention.

That is, the present invention provides a photosensitive composition containing a polyurethane resin having a carboxyl group and, if necessary, a hydroxyl group and/or a nitrile group, and a diazo resin, in which the diazo resin is a repeater represented by the general formula (I). unit, or each has at least one repeating unit represented by general formulas (I) and (II), and the ratio of aromatic hydrogen in the diazodiphenylamine skeleton to methylene or methine hydrogen connecting the skeleton is at least The object of the present invention is to provide a photosensitive composition characterized in that it has a molecular weight of 2.5 or more.

(I) (II) In the formula, R,
represents a hydrogen atom, an alkyl or alkoxy, hydroxy, or carboxy ester group which may have a substituent. Preferably, it represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a hydroxy group.

R2 represents a hydrogen atom, an alkyl group, or a phenyl group, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. R3 represents a hydrogen atom, an alkyl group, or an alkoxy group, preferably a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms. X- represents an alkyl having 3 or more carbon atoms or an anion of naphthalenesulfonic acid having at least one alkoxy group, and Y- represents an anion of other organic sulfonic acids.

Specifically, X- is isopropylnaphthalene sulfonic acid,
Butylnaphthalenesulfonic acid, hexylnaphthalenesulfonic acid, octylnaphthalenesulfonic acid, butoxynaphthalenesulfonic acid, octyloxynaphthalenesulfonic acid, dodecyloxynaphthalenesulfonic acid, diisopropylnaphthalenesulfonic acid, dibutylnaphthalenesulfonic acid, dioctylnaphthalenesulfonic acid, didodecylnaphthalene Included are anions of naphthalene sulfonic acids such as sulfonic acid, dibutoxynaphthalene sulfonic acid, triisopropylnaphthalene sulfonic acid, and tributylnaphthalene sulfonic acid.

Specific examples of Y- include butylbenzenesulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, butoxybenzenesulfonic acid, dodecyloxybenzenesulfonic acid, p-toluenesulfonic acid, 2.5
-dimethylbenzenesulfonic acid, mesitylenesulfonic acid, p-acetylbenzenesulfonic acid, 5-nitro-〇-
Toluenesulfonic acid, 5-sulfosalicylic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfone 12-10-5-nitrobenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy anion of an aromatic sulfonic acid such as -4-hydroxy-5-benzoylbenzenesulfonic acid;
lauryl sulfonic acid, dioctyl sulfosuccinic acid, dicyclohexyl sulfosuccinic acid, camphor sulfonic acid,
Tolyloxy-3-propanesulfonic acid, nonylphenoxy-3-propanesulfonic acid, nonylphenoxy-4
-butanesulfonic acid, dibutylphenoxy-3-propanesulfonic acid, cyamylphenoxy-3-propanesulfonic acid, dinonylphenoxy-3-propanesulfonic acid, dibutylphenoxy-4-butanesulfonic acid, dinonylphenoxy-4-butane Includes anions of aliphatic sulfonic acids such as sulfonic acids.

In addition, when the diazo resin used in the present invention is a resin having at least one repeating unit of general formulas (I) and (n), the sulfonic acid anions used X-/Y-
The molar ratio is 1/99 to 99/L, preferably 20/L.
It is 80 to 80/20.

When such a specific diazo resin is combined with the above-mentioned polyurethane resin, its printing durability is further increased and a strong highlight image is obtained. Publication No. 59-3874
This was truly surprising since it was not observed in combination with diazo resins as described in Publication No. 7 and the like.

In the diazo resin used in the present invention, the ratio of aromatic hydrogen in the diazodiphenylamine skeleton to methylene or methine hydrogen connecting the skeleton is at least 2.5. As this ratio decreases, the molecular weight increases, but a value smaller than 2.5 results in a highly connected structure, which is unfavorable from the viewpoint of organic solvent solubility and alkali developability. This ratio can be calculated from the ratio of the respective integral values of nuclear magnetic resonance spectra (NMR).

Specifically, the diazo resin used in the present invention comprises a diazo monomer having a 4-diazodiphenylamine skeleton and a condensing agent such as formaldehyde, acetaldehyde, benzaldehyde, etc. in a molar ratio of 1:1.2 to 1:0.5, respectively. The condensate obtained by condensation in an acidic medium preferably in a ratio of 1:1 to 1:0.6 and the anion of the organic sulfonic acid X- alone or a mixture of X- and Y-. Obtained as a reaction product.

Specific examples of the diazo monomer include 4-diazodiphenylamine, 4'-hydroxy-4-diazodiphenylamine, 4'-methoxy-4-diazodiphenylaminomi4'-ethoxy-4-diazodiphenylamine 4/, -Propoxy-4-diazodiphenylamine 4/ i-propoxy-4-diazodiphenylamine, 4'-methyl-4-diazodiphenylamine, 4
'-Ethyl-4-diazodiphenylamine 4/.

-propyl-4-diazodiphenylamine, 4'=i-
7'pyr-4-diazodiphenylamine, 4'-n-
Butyl-4-diazodiphenylamine, 4'-hydroxymethyl-4-diazodiphenylamine, 4'-β-hydroxyethyl-4-diazodiphenylamine, 4'-
r-hydroxypropyl-4-diazodiphenylamine, 4'-methoxymethyl-4-diazodiphenylamine, 4'-ethoxymethyl-4-diazodiphenylamine, 4'-β-methoxyethyl-4-diazodiphenylamine, 4'-β- Ethoxyethyl-4-diazodiphenylamine, 4'-carbomethoxy-4-diazodiphenylamine, 4'-carboethoxy-4-diazodiphenylamine, etc., and their 2'- or 3'-positional isomers are included.

Furthermore, those in which an alkyl group having 1 to 3 carbon atoms or an alkoxy group is substituted at the 3-position of these diazo monomers are also included.

The molecular weight of the diazo resin used in the photosensitive composition of the present invention ranges from about 1000 to 100.000, preferably from about 1000 to 10.000.

The content of the diazo resin contained in the photosensitive composition of the present invention is 1 to 50% by weight, preferably 3 to 20% by weight.

Furthermore, in the present invention, in addition to the above-mentioned diazo resin, Japanese Patent Publication No. 47
-1167 publication, JP-A-50-118802 publication,
Japanese Patent Publication No. 52-7364 and Japanese Patent Publication No. 59-22
A diazo resin as described in specifications such as Japanese Patent No. 2834 may be used in combination in an amount of 50% by weight or less based on the diazo resin of the present invention.

On the other hand, the polyurethane resin suitably used in the present invention is mainly a polyurethane resin having a group having a carboxyl group in the main chain, and further having a hydroxyl group and/or a nitrile group as necessary, and preferably the following: A diisocyanate compound represented by general formula (I) and (
Included are polyurethane resins whose basic skeleton is a reaction product of a diol compound having a carboxyl group represented by IV) or (V).

0CN-R, -NCO' (II
I ) R3 HO-R6-C-R, -OH(rV)0OI1 110 Rs Ar R70H(V)Con)I In the formula, R1 is a divalent aliphatic or aromatic carbonized group which may have a substituent Indicates hydrogen. If necessary, R4 may contain other functional groups that do not react with isocyanate groups, such as ester, urethane, amide, and ureido groups.

R5 is a hydrogen atom, alkyl which may have a substituent,
It represents an aralkyl, aryl, alkoxy, or aryloxy group, preferably a hydrogen atom, an alkino group having 1 to 8 carbon atoms, or an aryl group having 6 to 15 carbon atoms. R6, R7,
R8 may be the same or different, and may be a single bond,
Indicates a divalent aliphatic or aromatic hydrocarbon that may have a substituent. Preferably, it is an alkylene group having 1 to 20 carbon atoms, an arylene group having 6 to 15 carbon atoms, and more preferably an alkylene group having 1 to 8 carbon atoms. Also, if necessary,
R6, R1, and R8 may contain other functional groups that do not react with isocyanate groups, such as ester, urethane, amide, ureido, and ether groups. Note that R3, R6,
Two or three of R7 and R8 may form a ring.

Ar represents a trivalent aromatic hydrocarbon which may have a substituent, preferably an aromatic group having 6 to 15 carbon atoms.

Specifically, the diisocyanate compound represented by the general formula (I) includes those shown below.

That is, 2.4-) lylene diisocyanate, a dimer of 2.4-tolylene diisocyanate, 2.6-) lylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4.4'-diphenylmethane diisocyanate, Aromatic diisocyanate compounds such as 1.5-naphthylene diisocyanate, 3.3'-dimethylbiphenyl-4,4'-diisocyanate, etc.; Fats such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate, etc. group diisocyanate compounds; alicyclic compounds such as isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) diisocyanate, 1°3-bis(isocyanatomethyl)cyclohexane, etc. Group diisocyanate compound; 1゜3-
Examples include diisocyanate compounds which are reaction products of diols and diisocyanates, such as adducts of 1 mol of butylene glycol and 2 mols of tolylene diisocyanate.

Further, the diol compound having a carboxyl group represented by the general formula (IV) or (V) specifically includes those shown below.

That is, 3,5-dihydroxybenzoic acid, 2,2-bis(
hydroxymethyl)propionic acid, 2゜2-bis(2-
hydroxyethyl)propionic acid, 2,2-bis(3-
hydroxypropyl)propionic acid, bis(hydroxymethyl)acetic acid, bis(4-hydroxyphenyl)acetic acid,
4.4-bis(4-hydroxyphenyl)pentanoic acid,
Examples include tartaric acid.

The hydroxyl group and/or IJ group optionally contained in the polyurethane resin of the present invention has the general formula (rV).
Alternatively, a part of the carboxyl group derived from (V) can be incorporated into the polyurethane resin by reacting with a halogen compound having a hydroxyl group and/or a di-IJ group in the presence of a base. In addition, in the case of a nitrile group, a diol compound having a nitrile group is expressed by the general formula (
It can also be introduced into the polyurethane resin by using it in combination with the diol compound IV) or (V).

The polyurethane resin of the present invention may be formed from a diisocyanate compound represented by the general formula (III) and two or more diol compounds having a carboxyl group represented by the general formula (IV) or (V).

Furthermore, a diol compound that does not have a carboxyl group and may have other substituents that do not react with isocyanate may be used in combination to the extent that the alkali developability is not reduced.

Specifically, such diol compounds include those shown below. Namely, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, 1,3-butylene glycol, l,fi-hexanediol, 2-butene- 1,4-diol, 2.2.4-)limethyl-1
．． 3-bentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexane dimetatool, tricyclodecane dimetatool, hydrogenated bisphenol A1 hydrogenated bisphenol F1 ethylene oxide adduct to bisphenol, to bisphenol Propylene oxide adduct, ethylene oxide adduct of bisphenol F, propylene oxide adduct of bisphenol F, ethylene oxide adduct of hydrogenated bisphenol Δ, propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-
xylylene glycol, dihydroxyethyl sulfone,
Bis(2-hydroxyethyl)-2,4-)lylene dicarbamate, 2゜4-tolylene-bis(2-hydroxyethylcarbamide), bis(2-hydroxyethyl)-
Examples include m-xylylene dicarbamate, bis(2-hydroxyethyl)iso7talate, and the like.

The polyurethane resin used in the present invention is prepared by mixing the above diisocyanate compound and diol compound in an aprotic solvent.
Add a known catalyst with activity according to each reactivity,
Synthesized by heating. The molar ratio of diisocyanate and diol compound used is preferably 0.8
:1 to 1.2:1, and if an isocyanate group remains at the end of the polymer, it is finally synthesized in a form in which no isocyanate group remains by treating with alcohols or amines.

The molecular weight of the polyurethane resin is preferably 1000 or more on weight average, more preferably 5,000 to 10
The range is 10,000.

These polyurethane resins may be used alone or in combination. The content of these polyurethane resins in the photosensitive composition is about 50 to 99.5% by weight, preferably about 55 to 95% by weight.

The photosensitive composition of the present invention may also contain other resins in an amount of 50% by weight or less based on the polyurethane resin. Examples of resins to be mixed include polyamide resin,
Examples include epoxy resins, polyacetal resins, acrylic resins, methacrylic resins, polystyrene resins, and novolac type phenolic resins.

The photosensitive composition of the present invention may contain dyes, pigments,
Performance can also be improved by adding stabilizers, fillers, surfactants, plasticizers, etc.

Suitable dyes include oil-soluble dyes such as C,I.

26105 (Oil Red RR), C, I.

21260 (Oil Bluelet #308), C, 1
, 74350 (oil blue), C, I.

52015 (methylene blue), C, I, 42
555 (cristle violet), C, I, 42595
(Victoria Pure Blue), etc.

As stabilizers, phosphoric acid, phosphorous acid, oxalic acid, p-)
Luenesulfonic acid, dipicolinic acid, malic acid, tartaric acid,
Examples include 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, butylnaphthalenesulfonic acid, and p-hydroxybenzenesulfonic acid.

The photosensitive composition of the present invention is usually used by dissolving it in a solvent, applying it to a suitable support, and drying it.

The coating weight is about 0.1-5 g/m'', preferably 0.3-3 g/m'', dry weight.

Such solvents include, for example, methanol, ethanol,
isopropanol, n-butanol, -butanol,
2-methoxyethanol, ■-methoxy 2-propanol, 2-ethoxyethanol, 2-methoxyethyl acetate, ethylene glycol, tetrahydrofuran,
Dioxane, dimethylsulfoxide, N,N-dimethylformamide, acetone, methyl ethyl ketone, etc. and mixtures thereof are used.

Supports to which the photosensitive composition of the present invention is applied include, for example, paper, plastics (such as polyethylene,
Paper laminated with polypropylene, polystyrene, etc., such as aluminum (also includes aluminum alloys).

), zinc, copper, etc., such as cellulose diacetate, cellulose triacetate, cellulose propionate,
Includes plastic films such as cellulose acetate, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc., and paper or plastic films laminated with or vapor-deposited with the metals listed above. . Among these supports, aluminum plates are particularly preferred because they are extremely dimensionally stable and inexpensive. Furthermore, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferred.

In addition, in the case of a support having a surface of metal, especially aluminum, surface treatments such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate, etc., or anodization treatment are performed. It is preferable that In addition, as described in U.S. Pat. after being anodized and then immersed in an aqueous solution of an alkali metal silicate, treated by a combination of mechanical and electrolytic roughening as described in U.S. Pat. No. 4,476.006. Also suitable are aluminum supports. The above-mentioned anodizing treatment may be carried out by electrolysis using an aqueous or non-aqueous solution of an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid, or boric acid, or an organic acid such as oxalic acid or misulfamic acid, or a salt thereof alone or in combination of two or more. This is carried out by passing an electric current through a liquid using an aluminum plate as an anode.

It is also preferable that the material is grained, anodized, and then sealed. Such pore sealing treatment is performed using a sodium silicate aqueous solution,
This is carried out by immersion in hot water and a hot aqueous solution containing an inorganic or organic salt, a steam bath, and the like.

Also effective is silicate electrodeposition as described in U.S. Pat. No. 3,658,662.

The photosensitive composition of the present invention coated on a support can form a line image,
Exposure through a transparent original having a halftone image or the like, followed by development with an aqueous developer, provides a negative relief image on the original.

Light sources used for exposure include carbon arc lamps, mercury lamps, xenon lamps, tungsten lamps, and metal halide lamps.

The photosensitive composition of the present invention has excellent solubility in organic coating solvents when coated on a support, and has excellent developability when unexposed areas are developed with an alkaline developer after coating, drying, and image exposure. Excellent. The obtained relief image has good abrasion resistance, oil sensitivity, and adhesion to the support, and when used as a printing plate, many good prints without printing stains can be removed.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Synthesis Examples and □Examples, but the content of the present invention is not limited thereto.

Synthesis Example 1 500+nl equipped with condenser and stirrer! 125 g (0.50 mol) of 4.4'-diphenylmethane diisocyanate and 2°2
-bis(hydroxymethyl)propionic acid 67g (0
, 50 mol> was added and dissolved in dioxane 290-. Add 1 g of N,N-diethylaniline as a catalyst,
The mixture was heated to reflux for 6 hours while stirring. After that, the reaction solution was diluted with 4 ml of water.
1. The mixture was poured into a solution of 40 mf of acetic acid with stirring to precipitate a white polymer.

This polymer was filtered, washed with water, and then dried under vacuum to obtain 185 g of polymer.

When the molecular weight was measured by gel permeation chromatography (GPC), the weight average (polystyrene standard) was 28.000. Further, the carboxyl group content was measured by titration and found to be 2.47 meq/g.

Furthermore, 40 g of this polymer was placed in a 300-meter round bottom flask equipped with a condenser and a stirrer, and 200 g of DMF was added.
ml! It was dissolved in Triethylamine 6,
After adding 3 g (0,062 mol) and heating to 80°C, 7.7 g (0,062 mol) of ethylene bromohydrin was added.
mol) was added dropwise over 10 minutes while stirring. Stirring was then continued for 2 hours.

After the reaction was completed, the reaction solution was poured into a solution of 41 ml of water and 20 ml of acetic acid with stirring to precipitate a white polymer.

This polymer was filtered, washed with water, and dried under vacuum to obtain 42 g of polymer.

It was confirmed by NMR measurement that the hydroxyethyl group was introduced into the carboxyl group, and the content of the remaining carboxyl group was measured by titration, and it was found to be 1.21.
meq/g. (Polyurethane (a)).

Synthesis Examples 2 to 14 Polyurethane resins having carboxyl groups were synthesized in the same manner as in Synthesis Example 1 using the diisocyanates and diol compounds shown in Table 1. For some of these, ethylene bromohydrin, ethylene cyanopromide IBI or ethyl bromide (C1) was further reacted with a portion of the carboxyl groups in the polyurethane resin.

Regarding these products, it was confirmed by NMR measurement that a hydroxyethyl group, a cyanoethyl group, or an ethyl group was introduced into the carboxyl group. Moreover, the molecular weight was measured by GPC, and the carboxyl group content was measured by titration. The measured carboxyl group contents are shown in Table 1.

In the table, A is ethylene bromohydrin, B is ethylene cyanopromide, and C is ethyl bromide, which was further reacted with a part of the carboxyl group.

Moreover, the molecular weights of all of them were 8.000 to 45,000 as a weighted average (polystyrene standard).

Synthesis Example 15 29.4 g of 4-diazodiphenylamine hydrogen sulfate (
0,100 mol) in 96% sulfuric acid 120 while cooling to 5°C.
Dissolved in g. Add 3.0 g of paraformaldehyde to this
(0,100+++ol) was added and stirred at 5°C for 1 hour. After that, the reaction solution was mixed with ice water for 1.51 hours! 260 g of a 50% aqueous solution of zinc chloride was added to precipitate a yellow precipitate. This yellow precipitate was filtered and dried under vacuum to obtain 30 g of zinc chloride double salt of 4-diazodiphenylamine-formaldehyde resin.

Zinc chloride double salt of the obtained 4-diazodiphenylamine-formaldehyde resin 15.6 g (0,050 mo
l) in 300 m of water, and 12.6 g (0,044 m
ol) and 3.8 g (0,011 mol) of the sodium salt of n-dodecylbenzenesulfonic acid in 200 ml of water
i' solution was added with stirring. The produced yellow precipitate was collected by filtration and dried to obtain 23 g of a mixed salt of butylnaphthalenesulfonic acid and n-dodecylbenzenesulfonic acid of 4-diazodiphenylamine-formaldehyde resin (diazo resin (a)).

Similarly, when the zinc chloride double salt of this 4-diazodiphenylamine-formaldehyde resin was replaced with hexafluorophosphate and the resulting diazo resin was measured by NMR, the ratio of aromatic hydrogen to methylene hydrogen was 3.5. Met.

Synthesis Examples 16 to 22 Using the zinc chloride double salt of the 4-diazodiphenylamine-formaldehyde resin obtained in Synthesis Example 15, the anion of the organic sulfonic acid shown in Table 2 was used as the counteranion in the same manner as in Synthesis Example 15. A diazo resin was synthesized.

Example 1 and Comparative Examples 1 and 2 The surface of an aluminum plate having a thickness of 0.24 mm was grained using a nylon brush and an aqueous suspension of 400 mesh pumice stone, and then thoroughly washed with water. This is 10
% sodium hydroxide aqueous solution at 70° C. for 60 seconds, washed with running water, neutralized with 20% nitric acid, and then subjected to the electrochemical roughening method described in JP-A-53-67507, i.e. ■E = 12.7 V, V, = 9. 160°C in a 1% nitric acid aqueous solution using a sinusoidal alternating waveform current of IV.
Electrolytic surface roughening treatment was carried out using a special anode electricity amount of Cron/dm'. Continue to immerse in 30% sulfuric acid aqueous solution at 55°C.
After being desmutted for 2 minutes in a 7% sulfuric acid aqueous solution, it was anodized with aluminum oxide (the amount was 2.0 g/m'. Then, it was coated with silicic acid at 70°C).
It was immersed in a 3% aqueous solution of IJum for 1 minute, washed with water and dried. The following photosensitive solution was applied to the aluminum plate obtained as described above using a wheeler, and dried at 80° C. for 2 minutes. The dry weight was 2.0 g/m'.

Further, the diazo resin and polyurethane resin used in the following photosensitive solution are shown in Table 3.

(Photosensitive liquid) Next, as a comparative example, a photosensitive liquid was applied and dried in the same manner as in Example 1, except that the following diazo resin was used in the photosensitive liquid.

The dry weight was 2.0 g/m'.

(Diazo resin used in comparative example) Comparative example 1 4-diazodiphenylamine of synthesis example I5
PF, -salt of formaldehyde resin.

Comparative example 23-methoxy-4-diazodiphenylamine
Mesitylene sulfonate of condensate of 1 mol and 1 mol of 4,4'-bis(methoxymethyl)-diphenyl ether.

[Printing performance evaluation]

Each of the photosensitive lithographic printing plates thus obtained was image-exposed for 1 minute from a distance of 1 m using a PS light manufactured by Fuji Photo Film Co., Ltd., and after being immersed in the following developer for 1 minute at room temperature, The unexposed areas were removed by lightly rubbing the surface with a wafer to obtain lithographic printing plates (I) to (■) with bright blue images.

(Developer) Each printing plate was printed on high-quality paper with a commercially available ink using a Heidelberg KOR type printing machine.

The printing durability of the lithographic printing plates (I) to (■) and the strength of the highlight image were examined by rubbing strongly with absorbent cotton during development during the preparation of each lithographic printing plate, and the results were as shown in Table 3. Ta.

As shown in Table 3, the lithographic printing plates (I) to (VT) using the photosensitive composition of the present invention are the same as those of the comparative examples (■) to (■).
It has a longer print life than the previous model, and the strength of the highlight image is also very good.

Example 2 and Comparative Example 3 In the photosensitive liquid of Example 1, <
A lithographic printing plate (IX) was prepared in the same manner as in Example 1 using a photosensitive solution using the following diazo resin.

In order to demonstrate the excellent properties against printing stains of the present invention, the lithographic printing plates (I) to (VI) prepared in Example 1 were
x) was used to print on high-quality paper in the same manner as in Example 1.

When the printing stains of the lithographic printing plates (I) to (VI) and (IX) were examined, the results were as shown in Table 4.

(Diazo resin used in comparative example) Comparative example 3 In Synthesis example 15, only the amount of paraformaldehyde added was changed to 4.5 g (0,150 mol), and the ratio of aromatic hydrogen to methylene hydrogen was 2.0. Diazo resin.

As can be seen from Table 4, the lithographic printing plates (I) to (VI) using the photosensitive composition of the present invention had no printing stains during printing and were very superior compared to the comparative example (IX). It is something.

Claims (1)

[Claims] Carboxy group, and optionally hydroxyl group and/or
Or, in a photosensitive composition containing a polyurethane resin having a nitrile group and a diazo resin, the diazo resin has a repeating unit represented by the general formula (I), or the diazo resin has a repeating unit represented by the general formula (I) or (II). 1. A photosensitive composition having at least one repeating unit each, and having a ratio of aromatic hydrogen in the diazodiphenylamine skeleton to methylene or methine hydrogen connecting the skeleton of at least 2.5. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) [In the formula, R_1 is a hydrogen atom, alkyl or alkoxy that may have a substituent, hydroxy, or a carboxyester group, R_2 is a hydrogen atom, alkyl,
or represents an aryl group, R_3 represents a hydrogen atom, alkyl, or an alkoxy group, and X^- represents an alkyl group having 3 or more carbon atoms, or at least one alkoxy substituent.
Indicates the anion of naphthalene sulfonic acid that has Y^
- indicates an anion of other organic sulfonic acid. ]