JP2712564B2 - Photosensitive composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photosensitive composition suitable for producing a photosensitive lithographic printing plate. More specifically, the present invention relates to a photopolymerizable photosensitive composition using a novel polyurethane resin which is excellent in quality such as coating properties and stability over time, is easy to manufacture, and is inexpensive.

[Conventional technology]

Conventionally, many image forming methods using a photopolymerizable composition are known. For example, a photosensitive composition comprising an addition-polymerizable ethylenically unsaturated compound, a photopolymerization initiator, and, if necessary, an organic polymer binder, a diazo resin, a colorant, and a stabilizer is prepared. There is known a method of preparing a photosensitive material provided with a layer of a photosensitive composition by applying the composition on a support without solvent or by dissolving it in an organic solvent. The photosensitive material can be image-exposed with actinic rays to cure the exposed portions, and the unexposed portions can be removed with a developer to form a cured relief image.

Such a photopolymerizable composition has been conventionally used for forming various images such as a photosensitive lithographic printing plate, a photosensitive resin relief plate, a screen printing plate, a photoresist, and a color proof.

When the photopolymerizable composition is used as a photosensitive image forming layer suitable for an aqueous alkali developable photosensitive lithographic printing plate,
Generally, alkali-soluble or swellable organic polymer binders are commonly used.

Examples of such an organic polymer binder include, for example, an addition polymer having a carboxyl group in a side chain (for example, a copolymer of methacrylic acid and another vinyl compound; a partially esterified maleic acid copolymer and the like), Addition polymers having an ethylenically unsaturated bond and a carboxyl group in the side chain (for example, a carboxyl group-containing vinyl copolymer having a part thereof added with an oxirane ring-containing ethylenically unsaturated compound; allyl methacrylate and methacrylic acid) A polyvinyl acetal resin and a modified product thereof (eg, a cyclic acid anhydride adduct; an alkyl phosphinic acid isocyanate adduct; an isopropenyl sulfonyl isocyanate adduct); a polyurethane resin having a carboxyl group in a side chain; Polyurethane resin having ethylenically unsaturated bond and carboxyl group in side chain It is known.

Among these, the photopolymerizable composition containing a polyurethane resin having an allyl group and a carboxyl group in the side chain can be developed with an aqueous alkaline developer, is less susceptible to polymerization inhibition by oxygen, has abrasion resistance, It is applied to lithographic printing plates with high printing durability.

As a method for producing this polyurethane resin, generally,
In an organic solvent, by a polyaddition reaction of a diol compound having a carboxyl group and a diisocyanate compound, to produce a polyurethane resin having a carboxyl group in a side chain,
Next, a part of the carboxyl group is reacted with an allyl group-containing halogen compound in the presence of a base. Further, in order to remove by-products, a process of throwing into a large amount of water, separating and purifying by precipitation, and drying is adopted.

However, these production processes were not suitable for industrial mass production. In the step of separation and purification,
There are problems such as odor at the time of work and safety to the human body, and it is necessary to treat a large amount of wastewater containing an organic solvent. Further, a large-sized drying facility is required to dry the water-containing polyurethane resin. As a result, the resulting polyurethane resin was expensive.

Further, since the introduction of the allyl group is a polymer reaction, there is a problem that it is difficult to control the introduction ratio and it is difficult to obtain a polyurethane resin having stable quality.

Furthermore, when a photosensitive solution is prepared using this separated and purified polyurethane resin and applied to a support, coating unevenness, cissing, spots, etc., which are considered to be caused by a trace amount of impurities remaining in the polyurethane resin, are likely to occur. There was a problem.

[Problems to be solved by the invention]

The problem to be solved by the present invention is a photosensitive composition, in particular, when used in the photosensitive composition of a photosensitive lithographic printing plate, it is possible to improve quality such as coating properties, stability over time, and Another object of the present invention is to provide a photosensitive composition which can provide high printing durability. Another object of the present invention is to provide a photopolymerizable photosensitive composition using a novel polyurethane which is simple and inexpensive to produce.

[Means for solving the problem]

The present invention provides (A) a polyurethane resin having an allyl group and a carboxyl group in a side chain, (B) an ethylenically unsaturated compound capable of addition polymerization, (C) a photopolymerization initiator, and if necessary, (D) a diazo resin. In a photosensitive composition containing
As the polyurethane resin, (1) a diisocyanate compound, (2) a diol compound having an allyl group, and (3)
The problem has been solved by using a product obtained by reacting a diol having a carboxyl group and / or a tetrabasic acid anhydride.

The polyurethane resin having an allyl group and a carboxyl group in the side chain used in the present invention is the following (A) or (B)
Can be synthesized.

(A) A diisocyanate compound is reacted with a diol compound having an allyl group and a diol component containing a diol compound having a carboxyl group.

(B) A diisocyanate compound is reacted with a diol component containing a diol compound having an allyl group in excess of a diol component, and then a tetrabasic acid anhydride is reacted.

As the diisocyanate compound used in the present invention,
For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylene diisocyanate. Aromatic diisocyanate compounds such as meta-xylylene diisocyanate, 4,4'diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate; hexamethylene diisocyanate; aliphatic diisocyanate compounds such as trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate; Alicyclic diisocyanate compounds such as isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane; Examples thereof include diisocyanate compounds derived from diols and diisocyanates, such as adducts of 1 mol of butylene glycol and 2 mol of tolylene diisocyanate.

Examples of the diol compound having an allyl group include, for example,
Glycerol α-monoallyl ether, trimethylolpropane monoallyl ether, pentaerythritol diallyl ether, N, N-diallyl tartaric acid diamide and the like can be mentioned.

Examples of the diol compound having a carboxyl group include 2,2-bis (hydroxymethyl) propionic acid, 2,2
-Bis (hydroxyethyl) propionic acid, 2,2-bis (3-hydroxypropyl) propionic acid, bis (hydroxymethyl) acetic acid, 3,5-dihydroxybenzoic acid, bis (4-hydroxyphenyl) acetic acid, 4,4 -Bis (4-hydroxyphenyl) pentanoic acid, tartaric acid, N, N-bis (2-
(Hydroxyethyl) 3-carboxypropionamide and the like.

Further, a diol compound having no allyl group or carboxyl group can be used in combination. Such diol compounds include, for example, ethylene glycol,
Diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, 2-butene-1,
4-diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol
F, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, bisphenol F ethylene oxide adduct, bisphenol F propylene oxide adduct, hydrogenated bisphenol A ethylene oxide adduct, hydrogenated bisphenol A Propylene oxide adducts, hydroquinone dihydroxyethyl ether, p-xylylene glycol, bis (2-hydroxyethyl) isophthalate, hydroquinone, bisphenol A, bisphenol F and the like can be mentioned.

The polyurethane resin of the above-mentioned method (a) is obtained by adding a catalyst as required in the diisocyanate compound, a diol component containing a diol compound having an allyl group and a diol compound having a carboxyl group, preferably in an organic solvent, It is synthesized at room temperature or by heating. The use ratio of the diisocyanate compound and the diol component is
The diol component is added to 1 mole of the diisocyanate compound.
A range from 0.7 to 1.3 moles is preferred. When the diol component is less than 0.7 mol or more than 1.3 mol, the molecular weight of the polyurethane resin is not sufficiently increased, and sufficient printing durability tends not to be obtained. Further, the ratio of the diol compound having an allyl group is 1000 polyurethane resin.
It is preferable to select such that the content of the allyl group is 0.3 mol or more based on g. When the amount is less than 0.3 mol, polymerization is liable to be inhibited by oxygen, and a printing plate having high printing durability tends to be not obtained. The proportion of the diol compound having a carboxyl group is preferably selected so that the acid value of the polyurethane resin is 10 to 200. When the acid value of the polyurethane resin is less than 10, the developability with an aqueous alkali developer is insufficient, and when the acid value of the polyurethane resin exceeds 200, the oil sensitivity and printing durability tend to decrease. Is not preferred.

In the above reaction, for example, dibutyltin dilaurate, dibutyltin diacetate, triethylamine, morpholine and the like can be used as a urethanization catalyst.

Examples of the organic solvent that can be used in the above reaction include methylene chloride, chloroform, dichloroethane, trichloroethane, trichloroethylene, monochlorobenzene,
Halogen solvents such as dichlorobenzene and carbon tetrachloride; hexane, heptane, cyclohexane, benzene,
Aliphatic or alicyclic or aromatic hydrocarbon solvents such as toluene and xylene; tetrahydrofuran, dioxane,
Ether solvents such as diethyl ether, ethyl propyl ether, dibutyl ether, ethylene glycol dimethyl ether; ester solvents such as glycol methyl ether acetate, glycol ethyl ether acetate, methyl acetate, ethyl acetate, butyl acetate;
Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-methyl-4-methoxy-2-
Ketone solvents such as pentanone; nitrogen-containing solvents such as acetonitrile, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, nitrobenzene and the like; dimethylsulfoxide and the like. These solvents may be used alone or in combination of two or more. You can also.

When an isocyanate group remains at the polymer terminal in the above reaction, it is preferable to inactivate an unreacted isocyanate group by treating with an alcohol, an amine or the like.

In the polyurethane resin of the above method (b), the diisocyanate compound and a diol component containing a diol compound having an allyl group may be added with a catalyst, if necessary, in an excess of the diol component, preferably in an organic solvent. The urethane diol is synthesized at room temperature or by heating, and then reacted with a tetrabasic acid anhydride at normal temperature or under heating.

Examples of the tetrabasic acid anhydride used in the present invention include pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-diphenyl Tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4'-sulfonyldiphthalic dianhydride Product, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4 '-[3,3'-(alkyl phosphoryl Diphenylene) -bis (iminocarbonyl)] diphthalic anhydride, adduct of glycol diacetate and trimellitic anhydride, adduct of hydroquinone diacetate and trimellitic anhydride, diacetyldiamine and trimellitic anhydride Aromatic tetraca such as adduct of Rubonic acid dianhydride; 5- (2,5-dioxotetrahydrofuryl) -3
-Methyl-3-cyclohexene-1,2-dicarboxylic anhydride (trade name "Epiclone B-4400", manufactured by Dainippon Ink and Chemicals, Incorporated), 1,2,3,4-cyclopentanetetracarboxylic diacid Anhydrides, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydrides such as tetrahydrofurantetracarboxylic dianhydride;
Aliphatic tetracarboxylic dianhydrides such as 2,3,4-butanetetracarboxylic dianhydride and 1,2,4,5-pentanetetracarboxylic dianhydride can be used.

The usage ratio of the diisocyanate compound and the diol component is preferably in the range of 1.05 to 2.0 mol of the diol component per 1 mol of the diisocyanate compound. The amount of the tetrabasic acid anhydride used is preferably 0.5 to 1.0 equivalent of the acid anhydride group of the tetrabasic acid anhydride per 1 equivalent of the hydroxyl group of urethanediol.

The content of the allyl group and the acid value are preferably selected so as to be the same as those in the method (a).

The weight average molecular weight of the polyurethane resin having an allyl group and a carboxyl group in the side chain produced by the above method (a) or (b) is preferably in the range of 2,000 to 150,000.

An addition-polymerizable ethylenically unsaturated compound and a photopolymerization initiator are added to the polyurethane resin thus obtained, and a diazo resin, a colorant, a stabilizer, and the like are added as necessary. Add coating solvent according to
It is the photopolymerizable composition of the present invention.

Examples of the photopolymerization initiator include α-carbonyl compounds described in US Pat. No. 2,666,661, acyloin ethers described in US Pat. No. 2,448,828, and US Pat. No. 2,722,512. Has been α
Hydrocarbon-substituted aromatic acyloin compounds, polyquinone compounds described in U.S. Pat. No. 3,046,127, and triarylbiimidazole / p-aminophenyl ketones described in U.S. Pat. No. 3,493,367. A trihalomethyl-S-triazine-based compound described in U.S. Pat. No. 4,239,850, U.S. Pat.
Oxadiazole compounds described in 4212970, acridine and phenazine compounds described in U.S. Pat. No. 3,751,259, benzothiazole compounds described in JP-B-51-48516, etc. The amount used is 0.5 to 0.2 with respect to the solid content of the composition.
A range of weight% is preferred.

The addition-polymerizable ethylenically unsaturated compound is a monomer or oligomer having a boiling point of 100 ° C. or more at normal pressure and having at least one, preferably two or more addition-polymerizable ethylenically unsaturated groups in one molecule. is there. As such a monomer or oligomer, for example, polyethylene glycol mono (meth) acrylate [hereinafter, methacrylate and acrylate are collectively referred to as (meth) acrylate]. Monofunctional (meth) acrylates such as polypropylene glycol mono (meth) acrylate and phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth)
Acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, hexanediol di (meth) acrylate, tri (acryloyloxyethyl) isocyanate, (meth) of polyhydric alcohol / alxylene oxide adduct Acrylate, (meth) acrylate of polyhydric phenol / alkylene oxide adduct, JP-B-48-41
Urethane acrylates described in JP-A-708-708, JP-B-50-6034 and JP-A-51-37193;
No. 183, JP-B-49-43191 and JP-B-52-30490, polyfunctional (meth) acrylates such as polyester acrylates and epoxy acrylates obtained by adding epoxy resin and (meth) acrylic acid. Can be mentioned.

The amount of the ethylenically unsaturated compound capable of undergoing addition polymerization is preferably in the range of 5 to 70% by weight based on the solid content of the composition.

As the diazo resin, there is a diazo resin represented by a salt of a condensate of a diazodiarylamine and an active carbonyl compound, and a photosensitive, water-insoluble and organic solvent-soluble resin is preferable.

Particularly preferred diazo resins are 4-diazodiphenylamine, 4-diazo-3-methyldiphenylamine, 4-diazo-4'-methyldiphenylamine, 4-diazo-
3'-methyldiphenylamine, 4-diazo-4'-methoxydiphenylamine, 4-diazo-3-methyl-
Organic or inorganic acid salts of condensates of 4'-ethoxydiphenylamine, 4-diazo-3-methoxydiphenylamine, etc. with formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, 4,4'-bis-methoxymethyldiphenyl ether, etc. .

Examples of the organic acid include methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, mesitylenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, propylnaphthalenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 2
-Hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,4-dihydroxybenzophenone, benzenephosphinic acid, and the like, and examples of the inorganic acid include hexafluorophosphoric acid, tetrafluoroboric acid, and thiocyanic acid. .

Further, a diazo resin having a main chain of a polyester group described in JP-A-54-30121; a polymer having a carboxylic anhydride residue described in JP-A-61-273538, and a diazo resin having a hydroxyl group. A diazo resin obtained by reacting a compound; a diazo resin obtained by reacting a polyisocyanate compound with a diazo compound having a hydroxyl group can also be used.

The amount of the diazo resin used is preferably in the range of 0 to 40% by weight based on the solid content of the composition, and if necessary, two or more diazo resins may be used in combination.

In addition, the photosensitive composition of the present invention may contain another organic polymer binder in an amount of 50% by weight or less based on the polyurethane resin. Examples of such an organic polymer binder include acrylic resin, polyamide resin, polyester resin, epoxy resin, polyacetal resin, polystyrene resin, and novolak resin.

Further, in order to improve the performance, known additives such as a thermal polymerization inhibitor, a dye, a pigment, a surfactant, a plasticizer, and a stability improver can be added.

Suitable dyes include, for example, basic oil-soluble dyes such as crystal violet, Maikai Green, Victoria Blue, methylene blue, ethyl violet, and rhodamine B. As a commercial product, for example,
"Victoria Pure Blue BOH" (manufactured by Hodogaya Chemical Industry Co., Ltd.), "Oil Blue # 603" (manufactured by Orient Chemical Industry Co., Ltd.) and the like. Examples of the pigment include phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone red, and the like.

Examples of the surfactant include an anionic surfactant, a nonionic surfactant, and a fluorine-based surfactant.

Examples of the plasticizer include diethyl phthalate, dibutyl phthalate, dioctyl phthalate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate, tri (2-chloroethyl) phosphate, and tributyl citrate.

Further, as known stability improvers, for example, phosphoric acid, phosphorous acid, oxalic acid, tartaric acid, malic acid, citric acid, dipicolinic acid, polyacrylic acid, benzenesulfonic acid, toluenesulfonic acid and the like can be used in combination.

The amount of these various additives varies depending on the purpose, but is generally preferably in the range of 0 to 30% by weight of the solid content of the photopolymerizable composition for a lithographic printing plate of the present invention.

Further, a coating solvent can be added as needed. Examples of such a coating solvent include an organic solvent used for producing the above-mentioned polyurethane resin; methanol, ethanol, propanol, butanol, tetrahydrofurfuryl alcohol, benzyl alcohol, diacetone alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl. Ether, propylene glycol monomethyl ether, ethylene glycol monophenyl ether, cyclohexanol and the like are suitable, and a mixed solvent thereof is suitable. In some cases, a mixed solvent with water can also be used.

The photosensitive composition thus produced is applied to a support by a known coating method such as dip coating, curtain coating, roll coating, spray coating, wheeler coating, spinner coating, air knife coating, doctor knife coating, and the like. You.

As the support, for example, aluminum, zinc, copper,
Metal plate of stainless steel, iron, etc .; plastic film of polyethylene terephthalate, polycarbonate, polyvinyl acetal, polyethylene, etc .; paper coated with synthetic resin melted or coated with synthetic resin solution, metal layer on plastic film by vacuum evaporation, lamination, etc. Provided composite material; and other various materials used as a support for a printing plate. In the case of a support having a metal surface, particularly an aluminum surface, it is preferable that a surface treatment such as a graining treatment, an anodic oxidation treatment, and a hydrophilic treatment is performed. The amount of coating is usually about 0.5 to about 5 g / m ² on a dry weight basis.

After coating, the coating is dried by a known method to obtain a photosensitive lithographic printing plate provided with a photosensitive layer on a support. The photosensitive layer of this photosensitive lithographic printing plate is subjected to image exposure with a negative image to cure the exposed portion of the photosensitive layer, to make it insoluble, and then developed with an aqueous alkaline developer to dissolve and remove the unexposed portion, thereby supporting the photosensitive layer. A lithographic printing plate with the corresponding image formed on the body is obtained.

Suitable light sources used for exposure include, for example, carbon arc lamps, mercury lamps, metal halide lamps, xenon lamps, chemical lamps, lasers, and the like.

Examples of the aqueous alkaline developer include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, and sodium metasilicate. , Sodium carbonate, aqueous ammonia, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, monomethylamine,
An aqueous solution containing an alkaline agent such as dimethylamine, triethylamine, or the like can be given. In order to further improve the solubility of the unexposed portion of the photosensitive layer and the permeability of the developer, anionic surfactants such as sodium isopropylnaphthalenesulfonate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, and sodium dialkylsulfosuccinate are used. A solvent such as benzyl alcohol, N-benzylethanolamine, phenoxyethanol, diacetone alcohol, methyl cellosolve, or isopropyl alcohol can also be added.

The photosensitive composition of the present invention is useful as a photopolymerizable composition for a lithographic printing plate, but is not necessarily limited to this use, and a resin relief plate, a screen printing plate,
It can also be used for applications such as photoresists, color proofs, and hologram forming materials.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

(Synthesis Examples 1 to 7) To a reactor equipped with a cooling pipe and a stirrer, a diisocyanate compound, a diol compound having a carboxyl group, a diol compound having an allyl group, and a solvent in the types and amounts described in Table 1 were added, A 40% by weight solution was obtained. While stirring in a dry nitrogen gas atmosphere, the temperature was gradually raised to 60 ° C. over 2 hours. Next, dibutyltin dilaurate was used as a catalyst.
0.5 g was added, and the mixture was further reacted at 90 ° C. until the ratio of reactive NCO became 0.5% or less (about 6 to 8 hours). Next, the temperature was lowered to 80 ° C., 10.0 g of methanol was added, and the mixture was treated for 2 hours to obtain a polyurethane resin solution having an allyl group and a carboxyl group in a side chain.

Acid value (solid content conversion value) and GP of this polyurethane resin
Table 1 shows the weight average molecular weight (in terms of polystyrene) measured by the C analysis.

Further, as a result of NMR analysis and IR analysis, it was confirmed that an allyl group and a carboxyl group were introduced into the polyurethane resin.

(Synthesis Example 8) 250 g (1.0 mol) of 4,4'-diphenylmethane diisocyanate, 134 g (1.0 mol) of 2,2-bis (hydroxymethyl) propionic acid and 580 g of dioxane were placed in a reactor equipped with a cooling pipe and a stirring device. In addition, the mixture was stirred under a dry nitrogen gas atmosphere. N, N-diethylaniline (2 g) was added as a catalyst, and the mixture was heated and refluxed for 8 hours with stirring. Thereafter, the reaction solution was poured into a solution of water 8 and acetic acid 80 ml with stirring to precipitate a polymer. The polymer was filtered, washed with water, and dried under vacuum to obtain 370 g of a polyurethane resin having a carboxyl group in a side chain. As a result of GPC analysis, this polyurethane resin had a weight average molecular weight of 28,000, and an acid value of 138.
It was five.

Further, 80 g of this polyurethane resin was put into a reactor equipped with a cooling tube and a stirrer, and dissolved in 400 ml of dimethylformamide. To this solution was added 12.6 g of triethylamine (0.124 g).
Mol) and heated to 80 ° C, then 15.0 g of allyl bromide
(0.124 mol) was added dropwise over 10 minutes with stirring. Then, after continuing to stir for 2 hours, the reaction solution was water 8 and acetic acid 400m
The solution was poured into the solution (1) with stirring to precipitate a polymer. The polymer was filtered, washed with water, and dried under vacuum to obtain 82 g of a polyurethane resin having an allyl group and a carboxyl group in a side chain (Comparative polyurethane resin-1).

This polyurethane resin has an acid value of 67.0, and
As a result of NMR analysis and IR analysis, it was confirmed that an allyl group and a carboxyl group had been introduced.

(Example) (1) Preparation of a photosensitive lithographic printing plate A 0.30 mm thick aluminum plate was coated with a nylon brush and 40
A 0-mesh aqueous suspension of pamistone is used to grain the surface, and then the current density is 2 A / dm ^{2 in a} 20% sulfuric acid electrolyte.
To form an oxide film of 2.7 g / m ² .
Thereafter, the support was immersed in a 3% aqueous solution of No. 3 sodium silicate at 60 ° C. for 1 minute, washed with water and dried to obtain a support.

The following photosensitive solution is applied to this support with a roll coater,
The photosensitive lithographic printing plate was obtained by drying at 100 ° C. for 2 minutes. At this time, the weight of the dried coating film was 2.0 g / m ² .

(2) Preparation of a lithographic printing plate A film of a dot negative image and a step of 0.15 step wedge are brought into close contact with the photosensitive lithographic printing plate obtained in (1),
A metal halide lamp with an output of 1 kW (1 m from Iwasaki Electric Co., Ltd.)
0 ") for 85 seconds. Then, use the following developer
Development was performed at 5 ° C. for 1 minute to obtain a lithographic printing plate.

(3) Evaluation of photosensitive lithographic printing plate and lithographic printing plate Coating properties and aging stability of photosensitive lithographic printing plate The printing durability of the lithographic printing plate was evaluated, and the results are shown in Table 1.

 The test conditions are shown below.

-Coating properties: The coating state after coating and drying was visually observed and evaluated.

Stability over time: The photosensitive lithographic printing plate was stored at 60 ° C. in a humidity of 75% for 3 days, and then exposed and developed under the same conditions as described above. Immediately after the production of the photosensitive lithographic printing plate, compared with the exposed and developed one,
Developability and the like were evaluated.

Printing durability: A lithographic printing plate was prepared in the same manner as in (2), except that exposure was performed for an exposure time at which the light sensitivity became 5 steps. Attach this lithographic printing plate to Roland Fabolit printing machine,
Printing was performed using a 400-fold diluted solution of the printing ink "GAPS-G Beni" (manufactured by Dainippon Ink and Chemicals, Inc.) and fountain solution "DH-78" (manufactured by Dainippon Ink and Chemicals, Inc.). Was. 20
At the time of printing 10,000 sheets, it was evaluated whether or not a printed matter faithful to the original surface could be obtained without causing dot thickening, plate skipping and the like.

(Effect of the Invention) The photosensitive composition of the present invention contains a polyurethane resin having an allyl group and a carboxyl group in a specific side chain, and particularly when a photosensitive lithographic printing plate is used, coating properties, Quality such as stability over time can be improved, and high printing durability can be obtained. Further, the photosensitive composition of the present invention is economically advantageous because a novel polyurethane resin which is simple and inexpensive to produce is used.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-232217 (JP, A) JP-A-54-53193 (JP, A) JP-A-1-245245 (JP, A) JP-A-60-1985 43896 (JP, A) JP-A-59-36246 (JP, A) JP-A-55-717 (JP, A)

Claims (1)

(57) [Claims] 1. A polyurethane resin having an allyl group and a carboxyl group in a side chain, (B) an ethylenically unsaturated compound capable of addition polymerization, (C) a photopolymerization initiator, and if necessary, (D) a diazo compound. In a photosensitive composition containing a resin,
The polyurethane resin is obtained by reacting (1) a diisocyanate compound, (2) a diol compound having an allyl group, and (3) a diol compound having a carboxyl group and / or a tetrabasic acid anhydride. Characteristic photosensitive composition.