JP2000338653A - Photosensitive composition, original plate for printing and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive composition on which images can be written with laser light in the region from near IR to IR, requiring not heating before the development of a latent image and having good shelf stability and to obtain a computer-to-plate(CTP) type original plate which can be formed by a direct photomechanical process using a digital signal of a computer or the like and for which a conventional developing apparatus and a conventional printer can be utilized at it is. SOLUTION: The photosensitive composition contains an alkali-soluble crosslinking agent, a water resin having a functional group capable of crosslinking with the crosslinking agent and an IR absorber. The alkali-soluble crosslinking agent is an amino compound or amino resin, the water resin is a dispersion of fine resin particles which are crosslinkable. The original plate has a photosensitive layer comprising one of the above photosensitive compositions on the substrate. An image is formed on the photosensitive layer with laser light and developed with a basic aqueous solution or water. The laser light has the maximum intensity in the region of 760-3,000 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photosensitive composition using light in the near infrared region. More specifically, the present invention relates to a photosensitive composition in which a latent image is obtained by irradiation with a high-power laser beam in the near infrared region, and the latent image is developed using a basic aqueous solution or water to form an image. The photosensitive composition of the present invention is widely used such as a resist for a color filter, a resist for a printer substrate, and a color proof. The printing plate precursor of the present invention is used as a lithographic printing plate precursor used in the field of offset printing, in particular, as a so-called computer-to-plate (CTP) plate which can be directly made from digital signals by a computer or the like.

[0002]

2. Description of the Related Art In recent years, with the advance of computer image processing technology, a method of directly writing an image on a photosensitive layer by light irradiation corresponding to a digital signal has been developed. A computer-to-plate (CTP) system that directly forms an image on a plate material without using the system for a lithographic printing plate and outputting to a silver halide mask film has attracted attention.

[0003] A thermal CTP system using a high-power laser beam having a maximum intensity in the near infrared or infrared region as a light source for light irradiation requires a compact, high-power laser that can be easily obtained. In particular, attention has been paid to the fact that a high-resolution image can be obtained by the above exposure, and that the printing plate used in the method can be handled in a bright room.

A printing plate precursor used in a CTP system using such a light source is disclosed in Japanese Patent Application Laid-Open No. 10-22810.
Japanese Patent Application Laid-Open No. 9-1990 discloses a photosensitive layer containing a substance that generates an acid by heat (acid generating substance), an infrared absorber, a cross-linking agent that cross-links with an acid, and a resin having a functional group capable of cross-linking with the cross-linking agent. A printing plate precursor is disclosed. However, this printing plate precursor has a problem in the storage stability of the acid generating substance, and also requires a heat treatment before the development after laser irradiation in order to complete the cationic polymerization reaction accompanying the acid generation. Practical problems such as a problem in the reproducibility of halftone dots.

On the other hand, a printing plate precursor which does not require a heat treatment before laser development after laser irradiation is disclosed in JP-A-9-1712.
No. 49 discloses a printing plate precursor in which hydrophobic thermoplastic polymer particles dispersed in a hydrophilic resin are formed on a hydrophilic substrate. This printing plate precursor forms an image by utilizing the difference in solubility between the heat-fused resin fine particles and the non-fused resin fine particles in the developing solution, but forms hydrophobic fine particles insoluble in the developing solution into a hydrophilic resin. In addition, sensitivity, storage stability, and printing durability are low due to the necessity of development, and there is a problem that heat treatment is essential after development in order to actually use as a printing plate. Japanese Patent Application Laid-Open No. HEI 9-171250 discloses a printing plate precursor in which a hydrophilic resin is crosslinked by heat in order to improve printing durability. No printing durability was exhibited, and there was a problem in storage stability.

Japanese Patent Application Laid-Open No. Hei 9-127683 discloses a printing plate precursor in which a self-water-dispersible thermoplastic resin particle layer which can be made lipophilic by heat is formed on the surface of a hydrophilic substrate. This printing plate precursor has low sensitivity because it does not contain an infrared absorber, and it may be necessary to form a peelable drying prevention film such as PET on the resin fine particle layer in order to enhance storage stability. there were. Further, when a polyvalent metal ion is used as a cross-linking agent for improving printing durability, the developing property tends to decrease with time.

[0007]

The first problem to be solved by the present invention is that an image can be written with laser light in the near-infrared region and a heat treatment is required before developing a latent image. Another object of the present invention is to provide a photosensitive composition having good storage stability and excellent printing durability.

The second problem to be solved by the present invention satisfies the above-mentioned first problem, and allows plate making directly from a digital signal from a computer or the like. Another object of the present invention is to provide a computer-to-plate (CTP) plate that can use a conventional printing apparatus as it is in printing.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a so-called PS has been known as a mechanism for forming a written image on a photosensitive composition layer by high-density energy light. Polymerization reaction by monomer and light energy of plate (negative PS plate) or modification by partial decomposition reaction of polymer by light energy (positive PS plate)
Plate), instead of the conventional mechanism using only a chemical reaction, the water generated in the image area is melted and / or fused together by heat generated by absorption of light energy,
A latent image is formed by a polymerization / condensation reaction with a crosslinking agent by heat, and a new method of developing the latent image by dissolving and removing the non-image area by immersing the latent image in a processing solution is completed, thereby completing the present invention. Reached.

That is, the present invention provides a photosensitive composition containing (I) an alkali-soluble crosslinking agent, an aqueous resin having a functional group capable of undergoing a crosslinking reaction with the crosslinking agent, and an infrared absorber. I do.

In order to solve the above-mentioned problems, the present invention provides (II) a photosensitive composition comprising an alkali-soluble crosslinking agent, an aqueous resin having a functional group capable of undergoing a crosslinking reaction with the crosslinking agent, and an infrared absorber. Provided is a printing plate precursor having a photosensitive layer comprising a photosensitive composition.

Further, the present invention provides a photosensitive composition comprising (III) an alkali-soluble crosslinking agent, an aqueous resin having a functional group capable of undergoing a crosslinking reaction with the crosslinking agent, and an infrared absorber. An image forming method is provided in which an image is formed on a photosensitive layer of a printing plate precursor having a photosensitive layer using a laser beam, and then developed using a basic aqueous solution or water.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous resin having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent used in the present invention includes a functional group capable of undergoing a crosslinking reaction with a crosslinking agent described later, for example, a carboxyl group,
A resin having a hydroxyl group, a glycidyl group, an amino group and the like, which is dissolved or dispersed in water.

Examples of a method for preparing an aqueous resin having a functional group capable of undergoing a cross-linking reaction with a crosslinking agent include a method of converting a resin into water while synthesizing the resin in water, and a method of converting a synthesized or previously prepared resin to water. One is. Examples of the former method include an emulsion polymerization method and a soap-free emulsion polymerization method, and the latter method includes a pulverization method of pulverizing a bulk polymer to obtain fine particles, an emulsification method of emulsifying a resin using an emulsifier, and a hydrophilic method. And a method of dissolving and dispersing a resin having a functional group in water.

In the pulverization method, since it is difficult to obtain a resin solution uniformly dissolved in water or a resin fine particle dispersion uniformly dispersed in water, it is used in the photosensitive composition of the present invention. Is inappropriate. On the other hand, in the emulsion polymerization method and the emulsification method, the emulsifier remains, but depending on the type and amount of the emulsifier, it affects sensitivity, ink adhesion, and the like.
Great care must be taken in selecting the emulsifier.

The method of dissolving and dispersing a resin having a hydrophilic group in water includes the use of no emulsifier, the introduction of various functional groups into the resin before dissolution and dispersion, and the dissolution or dispersion state of the resin in water. Because it can be easily changed,
It is excellent as a method for producing an aqueous resin used in the photosensitive composition of the present invention. Since the aqueous resin used in the present invention is required to have a functional group capable of reacting with a cross-linking agent, the method capable of introducing various functional groups is extremely advantageous. In general, some aqueous resins obtained by an emulsification method or a phase inversion emulsification method have a film forming property by themselves, and such an aqueous resin is preferably used in the present invention.

The aqueous resin used in the present invention is a resin having a hydrophilic group together with a functional group capable of crosslinking with a crosslinking agent.
Hereinafter, a method for producing such a resin will be described in detail.

The hydrophilic group contained in the aqueous resin used in the present invention includes, for example, anionic group, cationic group and nonionic group. In the method of forming an image using the printing plate precursor of the present invention, Using an alkali-soluble crosslinking agent to improve the developability, water as a developer, or considering that an alkaline developer is used, an anionic group as a hydrophilic group, and a nonionic group are preferable. In this case, an anionic group is preferable.

When using an anionic acrylic resin,
For at least one kind of the polymerizable composition as a raw material, a polymerizable monomer having an acid group is used, and if necessary, copolymerized with a polymerizable monomer containing another polymerizable vinyl group by a known and common method, What is necessary is just to neutralize the required amount with a base. When a functional group capable of performing a cross-linking reaction with a cross-linking agent is introduced into the resin during polymerization, a polymerizable monomer having a functional group capable of performing a cross-linking reaction with a cross-linking agent, a polymerizable monomer having an acid group, and
If necessary, another polymerizable monomer composition containing a polymerizable vinyl group may be similarly copolymerized and then neutralized with a base. Of course, when the functional group capable of undergoing a cross-linking reaction with the crosslinking agent is the same as the functional group in the polymerizable monomer having an acid group, it contains a polymerizable monomer having an acid group and, if necessary, other polymerizable vinyl groups. The polymerizable monomer composition can be produced in the same manner as described above.

Examples of the polymerizable monomer having an acid group include (meth) acrylic acid, crotonic acid, itaconic acid,
(Anhydrous) vinyl monomers having a carboxyl group such as maleic acid, fumaric acid, monobutyl itaconate and monobutyl maleate; vinyl monomers having a phosphate group such as acid phosphooxyethyl methacrylate;
Vinyl monomers having a sulfonic acid group, such as 2-chloro-acrylamido-2-methylpropanesulfonic acid;
Vinyl monomers having a sulfate group such as 2-sulfoethyl (meth) acrylate, and the like.

The polymerizable monomer having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent differs in the functional group capable of undergoing a crosslinking reaction depending on the crosslinking agent used. When an amino compound such as a phenol derivative, a melamine derivative, or a benzoguanamine derivative is used as the crosslinking agent, examples of the functional group capable of performing a crosslinking reaction include a hydroxyl group, an amino group, an amide group, a carboxyl group, and a glycidyl group. Considering the polymerization with a polymerizable monomer having an acid group, the use of a monomer containing an amino group that forms a salt with an acid group or a glycidyl group that reacts with an acid group may cause gelation,
As the polymerizable monomer having a functional group capable of undergoing a cross-linking reaction with a cross-linking agent, it is preferable to use a polymerizable monomer having a hydroxyl group, an amide group, and a carboxyl group.

Examples of the polymerizable monomer having a hydroxyl group include:
Examples include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like. Examples of the polymerizable monomer having an amide group include (meth)
Acrylamide and the like can be mentioned. Examples of the monomer having a carboxyl group include the vinyl monomers having a carboxyl group described in the above-mentioned polymerizable monomer having an acid group.

The crosslinking agent is not limited to an amino compound, and in that case, a polymerizable monomer having a functional group which reacts with a crosslinking agent which does not cause a problem such as gelling during polymerization can be arbitrarily used. .

Examples of other polymerizable monomers having a polymerizable vinyl group that can be used as necessary as a monomer constituting the aqueous resin include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylate. ) Isopropyl acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, N-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, butoxymethyl (meth) acrylate, (meth) acrylic acid Ethoxydiethylene glycol, tetrahydrofurfuryl (meth) acrylate, (meth) Acrylic acid isobornyl (meth) acrylate, benzyl (meth) acrylate hydroxymethyl, 2-hydroxyethyl (meth) acrylate,
(Meth) acrylates such as 2-hydroxypropyl (meth) acrylate; styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-
Methylstyrene, p-tert-butylstyrene, p-
Styrene-based monomers such as hydroxystyrene; itaconic esters such as benzyl itaconate; maleic esters such as dimethyl maleate; fumaric esters such as dimethyl fumarate; vinyl acetate, vinyl benzoate, vinyl versatate; Vinyl esters such as vinyl propionate; polymerizable nitriles such as (meth) acrylonitrile; (meth) acrylamide;
Allyl alcohol, and the like.

The polymerization method of the polymerizable monomer composition is as follows:
Although various methods such as bulk polymerization and solution polymerization can be used, simple solution polymerization is preferable, and an organic solvent is preferably used as a solvent to be used. The organic solvent is not particularly limited as long as it can dissolve the polymerizable monomer and the obtained polymer. Examples thereof include aromatic hydrocarbons such as benzene, toluene, and xylene; acetone, methyl ethyl ketone, and methyl isobutyl. Ketones such as ketone or cyclohexanone; esters such as ethyl acetate and butyl acetate; alcohols such as methanol, ethanol and isopropyl alcohol. These organic solvents can be used as a mixture of two or more kinds. Among these organic solvents, it is preferable to use a solvent which easily dissolves and disperses in water in a later step and has a relatively high affinity for water, and a low-boiling solvent which is easy to remove the organic solvent. Use is preferred. Examples of such a solvent include acetone, methyl ethyl ketone, and ethyl acetate.

The polymerization initiator used in the solution polymerization is as follows:
A known radical polymerization initiator may be used, for example,
To azo polymerization initiators such as 2,2-azobisisobutyronitrile and 2,2-azobis (2,4-dimethylvaleronitrile); to benzoyl peroxide, lauryl peroxide and tert-butylperoxy 2-ethyl And peroxide-based polymerization initiators such as xanoate.

As a method of synthesizing an anionic acrylic resin, besides the method of introducing an acid group during polymerization as described above, for example, an acid anhydride is added to a polymer having a hydroxyl group, and then a required amount of a base is added with a base. An anionic group can be introduced into the acrylic resin after polymerization, such as neutralization. Similarly, a functional group capable of reacting with a crosslinking agent can be introduced into the resin after polymerization.

When an anionic polyester resin is used as the aqueous resin, a dibasic acid and a diol compound are subjected to dehydration condensation so that the number of acid groups is increased stoichiometrically to obtain a polyester having an acid group. After this,
The polyester resin having a hydrophilic group can be obtained by neutralizing the required amount with a base. Alternatively, a dibasic acid and a diol compound are stoichiometrically subjected to dehydration condensation so that the number of hydroxyl groups is increased, and then a polyester having an acid group is obtained by adding an acid anhydride. By neutralizing the required amount with a base, a polyester resin having a hydrophilic group can be obtained.

Examples of the dibasic acid used as a raw material of the polyester resin include succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, hexahydroterephthalic acid and hexahydroisophthalic acid. Acids, tetrahydrophthalic acid, 2,6-naphthalenedicarboxylic acid, and the like.

Examples of the diol compound used as a raw material of the polyester resin include ethylene glycol, neopentyl glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, and 2,2-diethyl. -1,
3-propanediol, 1,4-butanediol, 1,
3-butanediol, 1,5-pentanediol, 1,
6-hexanediol, 1,4-cyclohexanedimethanol, alkylene oxide adduct of bisphenol A, alkylene oxide adduct of hydrogenated bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycarbonate diol, polycaprolactone diol, etc. Is mentioned.

Examples of the acid anhydride as a raw material of the polyester resin include dibasic acids such as phthalic anhydride, maleic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. Acid anhydrides; tribasic or tetrabasic acid anhydrides such as trimellitic anhydride and pyromellitic anhydride; and the like.

When a dibasic acid and a diol compound are dehydrated and condensed to obtain a polyester, a tribasic or higher polybasic acid such as trimellitic acid or pyromellitic acid, or glycerin, trimethylolpropane, or the like, as long as gelling does not occur. A trihydric or higher polyhydric alcohol compound such as pentaerythritol can be used in combination.

When a known and commonly used esterification catalyst such as dibutyltin oxide is used during the dehydration condensation, the desired reaction can be carried out more smoothly.

If the functional group capable of undergoing a crosslinking reaction with the crosslinking agent is a carboxyl group or a hydroxyl group, the above-mentioned method is used to neutralize the required amount with a base having a carboxyl group or a base having both a carboxyl group and a hydroxyl group. As a result, an anionic polyester having a functional group capable of reacting with the cross-linking agent is obtained, but a functional group capable of reacting with the cross-linking agent can be introduced into the polyester obtained by dehydration condensation.

Next, when an anionic urethane resin is used as the water-soluble resin, a urethane resin having an acid group can be obtained by condensing a diisocyanate compound, a diol compound, and a diol compound having an acid group. The resin having a hydrophilic group can be obtained by neutralizing the required amount with a base. When the functional group capable of crosslinking with the crosslinking agent is a carboxyl group, a diol compound having a carboxyl group may be used as the diol compound having an acid group.When the functional group capable of crosslinking with the crosslinking agent is a hydroxyl group, a diol compound, The amount (mol) of the hydroxyl group of the diol compound having an acid group is condensed under the condition that the amount (mol) of the isocyanate group of the diisocyanate compound is excessive, and then the required amount is neutralized with a base, whereby the anionic urethane having a hydroxyl group is obtained. A resin is obtained.

Examples of the diisocyanate compound as a raw material of the urethane resin include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4-diphenylmethane diisocyanate,
2,4-diphenylmethane diisocyanate, 2,2-
Diphenylmethane diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate diphenylmethane diisocyanate, 3,3-dimethoxy-4,4-
Biphenylene diisocyanate, 3,3-dichloro-
Aromatic diisocyanates such as 4,4-biphenylene diisocyanate and 1,5-naphthalene diisocyanate;

5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, lysine diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, 4,
4-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, trimethyl hexamethylene diisocyanate, hydrogenated xylylene diisocyanate (hydrogenated xylylene diisocyanate), 3,3-dimethyl-4,4-
Examples thereof include aliphatic diisocyanates such as dicyclohexylmethane diisocyanate and alicyclic diisocyanates.

When an isocyanate group is left at the terminal of the resin for the purpose of internal crosslinking of the resin fine particles as described later, the reaction between the isocyanate group and water is relatively slow, and aliphatic diisocyanates, alicyclic diisocyanates, etc. The use of is preferred.

Examples of the diol compound serving as a raw material of the urethane resin include ethylene glycol, 1,2
-Propanediol (1,2-propylene glycol), 1,3-propanediol (1,3-propylene glycol), 1,3-butanediol, 1,4-butanediol (1,4-butylene glycol), neo Pentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, Cyclohexane-1,4-dimethanol, and the like.

Furthermore, various diols, succinic acid, adipic acid, glutaric acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and glutaric anhydride are used as diol compounds as raw materials for urethane resins. Polyester diols which are condensates with dibasic acids or dibasic acid anhydrides such as acids, maleic acid, maleic anhydride and hexahydroisophthalic acid; γ-butyrolactone or ε-caprolactone using various diols as initiators Polyester diols such as poly (hexamethylene carbonate) diol; ethylene oxide, propylene oxide, butylene with one or more of various diols as initiators Oxide, styrene oxide or tetra Polyether diols which are single or two or more kinds of ring-opening polymers such as hydrofuran and the like can also be used.

As the diol compound serving as a raw material of the urethane resin, a copolymer of these diols can be used. These diol compounds may be used alone or in various combinations.

The diol compound having an acid group, which is a raw material of the urethane resin, includes, for example, 2,2-bis (hydroxymethyl) propionic acid and tartaric acid.

As long as the urethane prepolymer does not gel, a small amount of a polyol compound having an average functionality of more than 2 may be used, and a small amount of a polyisocyanate having an average functionality of more than 2 may be used. Compounds can be used in combination.

In the condensation reaction between the diisocyanate compound, the diol compound and the diol compound having an acid group, a solution reaction is preferred because the viscosity increases. The solvent to be used is not particularly limited as long as it is a solvent that does not react with the isocyanate group, but a relatively high-polarity solvent that can well dissolve the obtained urethane resin is preferable. Considering removal,
Solvents having a higher vapor pressure than water are preferred. Examples of such a solvent include acetone, methyl ethyl ketone, and ethyl acetate.

The urethane condensation reaction can be carried out in the absence of a catalyst. However, in order to accelerate the reaction and obtain the desired urethane resin in a short time, it is preferable to add a known and commonly used organometallic catalyst. .

Examples of the organometallic catalyst include cobalt naphthenate, zinc naphthenate, stannous chloride, stannic chloride, tetra-n-butyltin acetate, tri-n-butyltin acetate, and n-butyltin trichloride. , Trimethyltin hydroxide, dimethyltin dichloride, dibutyltin acetate, dibutyltin dilaurate or tin octenoate.

A functional group capable of undergoing a crosslinking reaction with a crosslinking agent can be introduced not at the same time as the resin synthesis but after the synthesis, similarly to the anionic self-water-dispersible acrylic resin and the anionic self-water-dispersible polyester resin. Any aqueous resin having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent can be used.

The resins having these acid groups introduced have an acid value of 5
It is preferably from 300 to 300 (mg-KOH / g of resin). When the acid value is less than 5, the dispersion stability in water is low because the hydrophilicity of the resin is low even when the resin is completely neutralized in the neutralization step thereafter, and when the acid value is 300 or more, the synthesis is substantially difficult. Becomes

The photosensitive composition of the present invention is coated on a support and then dried in a drying step. Since the resin does not undergo thermal denaturation such as fusion in the drying step, the photosensitive composition of the present invention may be used. The glass transition temperature of the aqueous resin is preferably 40 ° C. or higher. When long-term storage at a high temperature is required, the resin of the present invention preferably has a glass transition temperature of 50 ° C. or higher so as not to involve thermal denaturation such as fusion of the resin.

The resin having an acid group varies depending on the structure, composition, and the like of the resin, but generally has five to five acid groups contained in the resin.
Neutralize with 120% (equivalent) of base and neutralize acid value 5-30.
By setting it to 0, it becomes a resin having hydrophilicity. By changing the degree of neutralization, the resin can be dissolved or dispersed in water.
Here, “dissolution” refers to a state in which a resin solution (dispersion) becomes completely transparent when dissolved and dispersed in water, and “dispersion” refers to a state in which the resin solution (dispersion) is slightly turbid. Means completely milky like milk, and the resin does not immediately settle. As the aqueous resin used in the present invention, in consideration of storage stability and developability, it is preferable to use a resin in which the resin is dispersed. Such a resin is 0.00
It is an aqueous dispersion of resin fine particles of 5 to 1 micrometer (μm). Such an aqueous dispersion has a neutralized acid value of about 5
200 can be obtained. More specifically, dispersing by changing the neutralizing acid value in various ways, and freely changing the neutralizing acid value between a completely dissolved neutralizing acid value and a neutralizing acid value at which the resin can be stably dispersed. Can be.

As the base used for neutralization, for example,
Hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; amines such as triethylamine, tributylamine, triethanolamine and dimethylethanolamine; and aqueous ammonia.

The resin having a functional group and a hydrophilic group which can be crosslinked with the crosslinking agent thus obtained becomes an aqueous resin when dissolved or dispersed in water. Dissolved in water
When the resin is dispersed, the resin generally has an organic solvent and a solid content of 5 to increase the viscosity of the system and to improve workability.
It is preferable to use it after diluting it to 60%.
The organic solvent is not particularly limited as long as it dissolves the resin, but in order to dissolve and disperse the resin stably, it is preferable to use an organic solvent having a relatively high affinity for water. When removing the solvent, it is preferable to use an organic solvent having a higher vapor pressure than water.

Examples of such an organic solvent include ketone solvents such as acetone and methyl ethyl ketone; ether solvents such as diethyl ether, dioxane and tetrahydrofuran; alcohol solvents such as methanol, ethanol and isopropyl alcohol; ethyl acetate such as ethyl acetate. Ester solvents; halogen-based solvents such as dichloromethane, and the like. These solvents may be used alone or as a mixture of two or more.

When dissolving and dispersing a resin having a functional group and a hydrophilic group which can be crosslinked with a crosslinking agent in water, it is common to slowly add water to the resin. The resin solution may be added to water. Further, a water containing a neutralizing agent may be added to a resin having an acid group which is a precursor of the resin, or a resin solution having an acid group which is a precursor of the resin in water containing a neutralizing agent May be added.

As a stirrer used for dissolving and dispersing a resin having a functional group and a hydrophilic group crosslinkable with a crosslinker in water, a known and commonly used stirrer can be used. Alternatively, a dispersing machine such as an emulsifying dispersing machine that gives a shearing force may be used.

The aqueous resin obtained by this method is initially obtained as an aqueous dispersion containing an organic solvent, but may be used as it is, or may be used as an aqueous dispersion by removing the organic solvent under reduced pressure. Alternatively, it may be used as a powder after removing the organic solvent and water.

Further, when an aqueous resin dispersion is used as the aqueous resin used in the present invention, that is, when an aqueous resin fine particle dispersion is used, crosslinked resin fine particles obtained by crosslinking the resin fine particles can be obtained. In order to prepare crosslinked resin fine particles, a resin having a hydrophilic group is introduced with a functional group for intraparticle crosslinkage in advance, or a crosslinkable compound as a third component is added, so that the inside of the resin fine particles is three-dimensionally formed. It can be used as crosslinked resin fine particles, and has printing resistance and
It can be used for improving storage stability and adjusting sensitivity.

As a method for obtaining crosslinked resin fine particles, for example, a urethane resin having an isocyanate group at the terminal is used as a hydrophilic resin, dispersed in water, and then, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc. By adding a polyamine compound and three-dimensionally crosslinking the inside of the particles, crosslinked resin fine particles can be obtained. Alternatively, as a third component, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, bisphenol A type epoxy resin,
Using a polyfunctional glycidyl compound such as a phenolic epoxy resin, a glycidyl methacrylate copolymer, a glycidyl ester resin of a carboxylic acid, or an epoxy compound such as an alicyclic epoxy, disperse in water with a resin having a hydrophilic group, and then heat. In addition, crosslinked resin fine particles can be obtained by an intraparticle crosslinking reaction. in this case,
It is more preferable to remove the organic solvent before applying heat because fusion of the resin fine particles can be prevented. Alternatively, by using a urethane resin in which isocyanate groups are introduced in advance as a resin having a hydrophilic group, and further dispersing in water together with a hydrophobic polyisocyanate compound of the third component, and then adding a polyamine compound, the crosslink density in the particles is reduced. Increased crosslinked resin fine particles are obtained. The crosslinking method exemplified here is only a small part, and a known method of crosslinking in water can be used.

The amount of the crosslinkable functional group for crosslinking the inside of the particles is suitably 1.5 to 300 mmol per 100 g of the resin.
If the amount is less than 1.5 mmol, the effect of crosslinking cannot be obtained,
If it exceeds 300 mmol, it is practically difficult to synthesize.

Next, the alkali-soluble crosslinking agent used in the present invention will be described. By using a cross-linking agent in the photosensitive composition, at the time of laser irradiation, or at the time of burning described below, the image is cross-linked by heat, and a strong image is formed. This leads to a decrease in storage stability, especially a significant decrease in storage stability under wet conditions. Although the cause of the decrease in storage stability under wet conditions is unknown, the inventors have found that even when slight fusion between particles occurs due to heat during storage, storage stability can be maintained by using an alkali-soluble crosslinking agent. It has been found that the properties, in particular the degradation under wet conditions, can be prevented.

The alkali-soluble crosslinking agent referred to in the present invention is:
It refers to a cross-linking agent soluble in an alkali solution that cross-links the aqueous resin by heat, and includes, for example, those having both an anionic functional group and a cross-linkable functional group. Examples of the crosslinkable functional group include those having an amino group, a methylol group, and an alkoxymethyl group.

More specifically, amino resins such as melamine resins, guanamine resins and urea resins having anionic functional groups can be mentioned. In general, amino resins are "Uria Melamine Resin" (Nikkan Kogyo Shimbun, published in 1969),
"Lecture on Polymer Experiment 11: Polycondensation and Polyaddition Reaction" (Kyoritsu Shuppan, published in 1958), "Polymer Experiment 5 Polycondensation and Polyaddition" (Kyoritsu Shuppan, published in 1980), "Chemistry of paint resin" (Shokodo, 1972), "Plastic Materials Course 3 Melamine Resin" (Nikkan Kogyo Shimbun, 1957), "Polymer Synthesis Experimental Method" (Tokyo Kagaku Doujin, Showa 41)
Annual publication), the addition reaction product of melamine, guanamine, urea and aldehyde is polymerized,
It is alcohol-denatured if necessary. Therefore, an amino resin having an anionic group can be mentioned by performing an addition reaction and a polymerization reaction using a raw material having an anionic group in any of these.

More specifically, an amino resin derived from a compound having both a carboxyl group and an aldehyde group in the molecule, such as glyoxylic acid or succinic semialdehyde, may be mentioned. A mixture of at least one compound such as melamine, guanamine, or urea with a compound having both a carboxyl group and an aldehyde group in the molecule, such as glyoxylic acid and succinic semialdehyde, in part or all of the aldehyde Can be produced by an addition reaction.

Further, 2- and 3- represented by the general formula [I]
Also, amino resins derived from 4- (4,6-diamino-1,3,5-triazin-2-yl) benzoic acid are mentioned as examples, and 2-, 3- or 4- (4,6-diamino Amino resins derived from (-1,3,5-triazin-2-yl) benzoic acid are also mentioned by way of example.
2-, 3- or 4- (4,6-diamino-1,3,5-
Triazin-2-yl) benzoic acid alone or
It can be produced by reacting a mixture of at least one compound such as urea, melamine and benzoguanamine with an aldehyde compound.

[0065]

Embedded image

Among the compounds represented by the general formula [I], two compounds disclosed in JP-A-9-143169 are disclosed.
-(4,6-diamino-1,3,5-triazine-2-
Ill) Benzoic acid is obtained in high yield and purity and is preferably used.

These amino resins having an anionic group can be used as they are. However, in order to improve the storage stability, as described in the above-mentioned literature, a methylolation reaction or an alkyl etherification (acetal) reaction is carried out. It is preferable to carry out the reaction and use it.

Examples of the aldehyde compound include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, glyoxal and the like. Among these, use of formaldehyde and paraformaldehyde is preferred from the viewpoint of reactivity.

As the alcohol compound, it is preferable to use an aliphatic alcohol having a carbon chain of 4 or less, and examples thereof include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and i-butyl alcohol. These alcohol compounds may be used alone or in combination.

The amino resin derived from a compound having a carboxyl group and an aldehyde group in a molecule includes, for example, a compound having a carboxyl group and an aldehyde group in a molecule alone, or a compound having a carboxyl group and an aldehyde group in a molecule. A mixture of a compound having a carboxyl group and an aldehyde group in a molecule, and a mixture of a compound having another aldehyde compound,
At least one of melamine, guanamine, urea, etc.
About 40 to 12
It can be produced by reacting at 0 ° C. In general, aldehyde compounds, especially formaldehyde, and melamine,
The addition reaction with at least one compound such as guanamine or urea is performed by addition reaction between a compound having both a carboxyl group and an aldehyde group in a molecule and at least one compound such as melamine, guanamine or urea. Since the reaction proceeds rapidly, a compound having both a carboxyl group and an aldehyde group in the molecule in advance is subjected to an addition reaction with at least one compound such as melamine, guanamine, or urea, followed by an addition reaction with formaldehyde to form an anion. The functional group can be more uniformly introduced into the amino resin.

An amino compound or an amino resin derived from 2- (4,6-diamino-1,3,5-triazin-2-yl) benzoic acid is, for example, 2- (4,6-diamino-1,2,3-triamino-2-yl) benzoic acid. 3,5-Triazin-2-yl) benzoic acid alone or a mixture with at least one compound such as urea, melamine and benzoguanamine is mixed with an aldehyde compound and an alcohol compound and reacted at about 40 to 120 ° C. Can be manufactured.

When storage stability is required in the photosensitive composition of the present invention, low reactivity at low temperatures is required, and the photosensitive composition is used as a lithographic printing plate. In this case, since the ink is required to be further excellent in the ink inking property, an amino compound having few amino groups or methylol groups, that is, an amino compound having a highly alkyl etherified (acetalized) alkoxymethyl group is used. Alternatively, the use of an amino resin is preferred.

The use ratio of these crosslinking agents in the total solid content of the photosensitive material of the present invention is preferably in the range of 0.1 to 60% by weight, particularly preferably in the range of 1 to 40% by weight. If the use ratio of the crosslinking agent is less than 1% by weight, the effect of crosslinking cannot be obtained, and if it exceeds 40% by weight, the photosensitive composition layer of the present invention tends to become brittle, which is not preferable.

The infrared absorbent used in the present invention refers to a substance that generates heat by absorbing light in the photosensitive composition layer,
Such substances include, for example, various pigments or dyes.

Examples of the pigments used in the present invention include commercially available pigments, Color Index Handbook, "Latest Pigment Handbook, edited by Japan Pigment Technical Association, 1977", "Latest Pigment Application Technology" (CMC Publishing, 1986), Pigments described in "Printing Ink Technology" (CMC Publishing, 1984) can be used. Examples of the type of the pigment include a black pigment, a yellow pigment, an orange pigment, a brown pigment, a red pigment, a violet pigment, a blue pigment, a green pigment, a fluorescent pigment, and a polymer-bound dye. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these, carbon black is preferably used as a substance that efficiently absorbs light in the near infrared region and generates heat efficiently and is economically excellent. Also, grafted carbon black having various functional groups and good dispersibility is commercially available, for example, "Carbon Black Handbook 3rd Edition"
(Carbon Black Association, 1995), page 167, and "Characteristics and Optimum Blending and Utilization Techniques of Carbon Black" (Technical Information Association, 1997), page 111. It is suitably used in the invention.

These pigments may be used without being subjected to a surface treatment, or may be used after being subjected to a known surface treatment. Examples of the known surface treatment methods include a method of surface-coating a resin or wax, and a method of surface activity. And a method of attaching a reactive substance such as a silane coupling agent, an epoxy compound, or a polyisocyanate to the surface of the pigment. These surface treatment methods are described in “Properties and Applications of Metallic Soap” (Koshobo), “Latest Pigment Application Technology” (CMC
Publishing, 1986) and "Printing Ink Technology" (CMC Publishing, 1984).

The particle size of the pigment used in the present invention is 0.0
It is preferably in the range of 1 to 15 micrometers, more preferably in the range of 0.01 to 5 micrometers.

The dyes that can be used in the present invention include known dyes, and examples thereof include “Dye Handbook” (edited by The Society of Synthetic Organic Chemistry, published in 1970) and “Handbook of Color Material Engineering” (edited by the Color Material Association). , Asakura Shoten, 1989), "Technologies and Markets of Industrial Dyes" (CMC, 1983), "Chemical Handbook Applied Chemistry" (edited by The Chemical Society of Japan, Maruzen Shoten, 1986). Is mentioned. More specifically, azo dye, metal chain salt azo dye, pyrazolone azo dye, anthraquinone dye, phthalocyanine dye, carbonium dye, quinone imine dye, methine dye, cyanine dye, indigo dye, quinoline dye, nitro dye, xanthene dye And thiazine dyes, azine dyes, oxazine dyes and the like. Among these dyes, those that absorb near-infrared to infrared light are particularly preferred. Dyes that absorb near-infrared light or infrared light are described, for example, in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Cyanine dyes described in JP-A-58-173696 and 58-173.
Methine dyes described in JP-A-181690 and JP-A-58-194595;
JP-A-58-224793 and JP-A-59-481.
Nos. 87, 59-73996 and 60-52
Nos. 940 and 60-63744, naphthoquinone dyes, squalilium dyes described in JP-A-58-112792, and cyanines described in British Patent No. 434,875. Dyes, and near infrared absorbers described in US Pat. No. 5,156,938, and the like. Further, substituted arylbenzo (thio) pyridinium salts described in U.S. Pat. No. 3,881,924,
Trimethine thiapyrylium salts described in JP-A-7-142645, JP-A-58-181051, JP-A-58-220143, JP-A-59-146063, JP-A-59-146061 and the like. Pyrylium compounds, cyanine dyes described in JP-A-59-216146, U.S. Pat. No. 4,283,
475, pentamethine thiopyrylium salt described in JP-B-5-13514, 5-197
No. 02, and a near-infrared absorbing dye described in U.S. Pat. No. 4,756,993.

From the above-mentioned pigments or dyes, at least one suitable pigment or dye capable of absorbing a specific wavelength of a high-output light source described later and converting it into heat is selected and added to the photosensitive composition layer. Can be used.

When a pigment is used as an infrared absorber,
The amount of the pigment used is based on the total solid content of the photosensitive composition layer.
A range of 1 to 70% by weight is preferred, and a range of 3 to 50% by weight is particularly preferred. When the addition amount is less than 3% by weight, even if it absorbs light and generates heat, the amount of heat does not become sufficient to melt and crosslink the coexisting fine particles, and the addition amount is more than 50% by weight. However, the amount of heat generated is too large, and phenomena such as combustion and destruction occur, which tends to make it difficult to form a fused latent image suitable for forming an image.

When a dye is used as the infrared absorbing agent, the amount of the dye is preferably in the range of 0.1 to 30% by weight, preferably 0.5 to 2% by weight, based on the total solid content of the photosensitive composition layer.
A range of 0% by weight is particularly preferred. The amount of dye used is 0.1
When the amount is less than the weight%, even if it absorbs light and generates heat, the amount of heat does not become sufficient to melt the coexisting resin,
If the amount of addition is more than 30% by weight, the amount of heat generated is substantially saturated, and the effect of addition tends not to increase, such being undesirable.

The printing plate precursor of the present invention can be produced by applying a coating composition for a photosensitive composition layer on a support and then drying it. The coating composition for the photosensitive composition layer can be prepared by dispersing a pigment or dye in an aqueous resin solution (dispersion) and then mixing with a crosslinking agent. Further, the photosensitive composition layer coating liquid can also be prepared by dispersing a pigment or dye in water or a mixed solvent of water and an organic solvent, and then blending the dispersion with an aqueous resin and a crosslinking agent. Further, the photosensitive composition layer coating solution is obtained by dispersing a pigment or dye in a resin solution before aqueous conversion, and then dispersing the dispersion in water to form fine particles containing a pigment or dye therein (fine particles containing a dye or a pigment encapsulated therein). ) And then mixing with a crosslinking agent.

As the dispersing machine used for dispersing the pigment or the dye, known ones can be used. For example, an ultrasonic dispersing machine, a sand mill, an attritor, a bur mill,
Examples include a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, a pressure kneader, and a paint conditioner. Further, at this time, an organic solvent may be used in combination, and in that case, it is preferable to use a low-melting organic solvent that can be uniformly dissolved in water, and specifically, methanol, ethanol, n-propyl alcohol, isopropyl Alcohols such as alcohol, n-butanol, sec-butanol and t-butanol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as toluene and xylene Is mentioned.

Further, the photosensitive composition layer of the present invention may contain, if necessary, a resin soluble in an alkaline aqueous solution such as a phenolic novolak and a (meth) acrylic acid resin, an acid generator, a dissolution regulator and the like. Can also be added.

The photosensitive composition layer coating solution thus prepared may contain various auxiliaries for improving coating properties, for example, various natural water-soluble polymers and synthetic water-soluble polymers for adjusting viscosity, methanol, etc. And water-soluble organic solvents such as ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, ethylene glycol and propylene glycol, and various surfactants.

The coating solution of the photosensitive composition is preferably applied to a support by a conventionally known method after the solid content ratio in the application solution is adjusted to 1 to 50% by weight. As a coating method, specifically, a spin coating method using a spin coater or the like,
Dip coating, roll coating, curtain coating, blade coating, air knife coating, spray coating, bar coater coating, and the like.

The photosensitive composition layer coating solution coated on the support as described above is dried at room temperature to form a photosensitive composition layer. In order to dry in a shorter time, it is preferable to dry at 30 to 150 ° C. for 10 seconds to 10 minutes using a hot air dryer, an infrared dryer, or the like.

In the photosensitive composition layer of the present invention, after an image is written by a high-output laser in the near-infrared region, the non-image portion is removed by a developing method by a wet method. The developer used for the development treatment is an acidic aqueous solution or an alkaline aqueous solution. In consideration of corrosion of the substrate and the like, it is generally preferable to use an alkaline aqueous solution using an alkaline agent. As a high-power laser in the near infrared region, 7
Various lasers having a maximum intensity in the near infrared region of 60 nm to 3,000 nm, for example, a semiconductor laser, a YAG laser and the like can be mentioned.

Hereinafter, the case where the photosensitive composition of the present invention is applied to a lithographic printing plate precursor will be described.

When the photosensitive composition of the present invention is applied to a lithographic printing plate precursor, the photosensitive composition of the present invention may be provided on a support having a hydrophilic surface. That is, a lithographic printing plate precursor can be prepared by applying the photosensitive composition layer coating solution on a support having a hydrophilic surface and drying it as described above.

Examples of such a support include metal plates such as aluminum, zinc, copper, stainless steel, and iron;
Plastic films such as polyethylene glycol terephthalate (PET), polycarbonate, polyvinyl acetal, and polyethylene; composites in which a metal layer is provided on a paper or plastic film coated with a synthetic resin by fusion coating or a synthetic resin solution by vacuum evaporation or lamination Materials and the like. Of these, aluminum and the use of a composite support coated with aluminum are particularly preferred.

The surface of the aluminum support is desirably surface-treated for the purpose of increasing water retention and improving adhesion to the photosensitive layer. Examples of such a surface treatment method include, for example, a brush polishing method, a ball polishing method, an electrolytic etching, a chemical etching, a liquid honing, a sand blasting and the like as a surface roughening method, and a combination thereof, and in particular, an electrolytic etching. A surface roughening method comprising the use of is preferred.

As the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used. Among them, hydrochloric acid, nitric acid or a salt thereof is used. An electrolytic solution containing Further, the aluminum plate subjected to the surface roughening treatment is desmutted with an acid or alkali aqueous solution as required. The aluminum plate thus obtained is desirably subjected to an anodic acid value treatment, particularly desirably a method of treating the aluminum plate with a bath containing sulfuric acid or phosphoric acid.

Further, if necessary, US Pat.
Silicate treatment (sodium silicate, potassium silicate) described in U.S. Pat. Nos. 2,946,638 and 4,066,3,181,461. Potassium fluorozirconate treatment,
Phosphomolybdate treatment described in U.S. Pat. No. 3,201,247; British Patent 1,108,5
No. 59, an alkyl titanate treatment,
Polyacrylic acid treatment described in German Patent 1,091,433 and polyvinyl sulfone described in German Patent 1,134,093 and British Patent 1,230,447 Acid treatment, Japanese Patent Publication No. 44-640
No.9, JP-A-58-16839 and JP-A-5-16839, the phosphinic acid treatment described in U.S. Pat. No. 9,307,951 and the phytic acid treatment described in U.S. Pat.
8-18291, a treatment with a salt of a hydrophilic organic polymer compound and a divalent metal;
Those subjected to a hydrophilization treatment by undercoating of a water-soluble polymer having a sulfonic acid group described in JP 101651 A, those subjected to coloring with an acid dye described in JP-A-60-64352, US Patent 3,65
A process such as silicate electrodeposition described in Japanese Patent No. 8,662 can be performed.

Further, after graining treatment and anodic acid value treatment, sealing treatment is also preferred. Such a sealing treatment is performed by immersion in hot water or a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath, or the like.

Next, a method for preparing a printing plate using the printing plate precursor of the present invention will be described.

The lithographic printing plate of the present invention is a so-called computer-to-plate (CTP) plate in which an image can be directly written on a plate using a high-power laser based on digital image information from a computer or the like. is there. Examples of high-power lasers capable of forming an image on the printing plate precursor of the present invention include various semiconductor lasers, YAG lasers, and the like. The dye can be used by selecting from the above-mentioned pigments or dyes and adding it to the photosensitive composition layer.

The photosensitive composition layer of the printing plate precursor of the present invention comprises:
After the image is written by the high-power laser, the non-image portion is removed by a wet process by a developing process. The developer used at this time is an alkaline aqueous solution containing an alkaline agent when the aqueous resin contained in the photosensitive composition layer has an anionic group.

Examples of the alkaline agent used in the developer of the printing plate precursor of the present invention include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, and secondary or tertiary phosphoric acid. Inorganic alkali compounds such as sodium, potassium or ammonium salts, sodium metasilicate, sodium carbonate, ammonia; monomethylamine, dimethylamine, trimethylamine,
Monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine,
Amine organic alkali compounds such as n-butylamine, di-n-butylamine, monoethanolamine, diethanolamine, triethanolamine, ethyleneimine and ethylenediamine are exemplified.

The content of the alkali agent in the developer is 0.0
The range is preferably from 05 to 10% by weight, particularly preferably from 0.05 to 5% by weight. When the content of the alkali agent in the developer is less than 0.005% by weight, the development tends to be poor. On the other hand, when the content is more than 10% by weight, adverse effects such as erosion of the image forming layer during development are caused. This is not preferred because of the tendency.

An organic solvent can be added to the developer of the printing plate precursor of the present invention. Examples of the organic solvent that can be added to the developer include, for example, ethyl acetate, butyl acetate, amyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate, butyl levulinate,
Methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether,
Benzyl alcohol, methyl phenyl carbitol, n
-Amyl alcohol, methyl amyl alcohol, xylene, methylene dichloride, ethylene dichloride, monochlorobenzene, and the like.

When the organic solvent is added to the developer, the content of the organic solvent is preferably 20% by weight or less, and more preferably 10% by weight.
The following are particularly preferred.

Further, in the above-mentioned developer, water-soluble sulfites such as lithium sulfite, sodium sulfite, potassium sulfite, and magnesium sulfite; Aromatic compounds; water softeners such as polyphosphates and aminopolycarboxylic acids; sodium isopropylnaphthalenesulfonate, sodium n-butylnaphthalenesulfonate, N-
Anionic surfactants such as sodium methyl-N-pentadecylaminoacetate and sodium lauryl sulfate, nonionic surfactants, cationic surfactants,
Various surfactants such as amphoteric surfactants and fluorine-based surfactants and various antifoaming agents can be used.

As the developer used in the image forming method of the present invention, the developer having the above composition is used. However, in practice, a commercially available developer for a negative PS plate or a positive PS plate is used. Can be used. A commercially available concentrated negative or positive developer diluted 1 to 1,000 times can be used as a developer for a printing plate precursor according to the present invention.

In the development of the printing plate precursor according to the present invention, after forming an image using a laser beam, the plate is immersed in a developer and then washed with water. The temperature of the developer is preferably in the range of 15 to 40 ° C., and the immersion time is preferably in the range of 1 second to 2 minutes. If necessary, the surface can be lightly rubbed during development.

After completion of development, the printing plate precursor of the present invention is subjected to washing with water and / or treatment with an aqueous desensitizing agent. Examples of the aqueous desensitizing agent include aqueous solutions of water-soluble natural polymers such as gum arabic, dextrin, and carboxymethyl cellulose; and aqueous solutions of water-soluble synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid. According to the above, an acid or a surfactant is added to these aqueous desensitizing agents. Thereafter, after being subjected to a treatment with a desensitizing agent, the printing plate precursor is dried and used for printing as a printing plate.

For the purpose of increasing the printing durability of the obtained printing plate, the above printing plate can be burned to form a printing plate. As the burning treatment, first, the printing plate obtained by the above-described treatment method is washed with water to remove a rinsing liquid and a gum liquid, and then squeegeeed.
Next, the surface conditioning liquid is spread evenly over the entire plate and dried. Burning is performed in an oven at 180 to 300 ° C for 1 to 30 minutes. After cooling the plate, the surface conditioning liquid is removed by washing with water, gummed and dried, and then used as a printing plate.
It is carried out by the process described above. In the printing plate precursor according to the present invention, the printing durability is significantly improved by this burning.

The surface conditioning liquid is used exclusively as an aqueous solution to be treated before the burning treatment so as to prevent the occurrence of background fouling after the burning treatment, and its main component is a surfactant, particularly preferably an anionic surfactant. 0.005 to 30 of surfactant and / or fluorine-based surfactant
Various acids, alkalis or salts are added to maintain the weight% and pH in the range of 2 to 11, preferably 3 to 10.

Examples of the anionic surfactant used in the surface conditioning solution include alkyl benzene sulfonate, alkyl diphenyl ether disulfonate, alkyl naphthalene sulfonate, aldehyde condensate of alkyl naphthalene sulfonic acid, α-olefin sulfonate, Surfactants having a sulfonic acid group such as an alkyl sulfonate; sulfate ester surfactants such as lauryl sulfate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkylphenyl ether sulfate; and the like.

Examples of the fluorosurfactant used in the surface conditioning liquid include carboxylate having a perfluoroalkyl group, sulfonate having a perfluoroalkyl group, and sulfate salt having a perfluoroalkyl group. , Anionic fluorosurfactants such as a phosphate having a perfluoroalkyl group; cationic fluorosurfactants such as an amine salt having a perfluoroalkyl group and a quaternary ammonium salt having a perfluoroalkyl group; Amphoteric fluorosurfactants such as fluoroalkylcarboxybetaines, aminocarboxylates having a perfluoroalkyl group, oligomers having a perfluoroalkyl group, polymers having a perfluoroalkyl group, sulfonamide polyethylene glycol having a perfluoroalkyl group Such nonionic fluorocarbon surfactant adducts, and the like.

Examples of the acid used for the surface conditioning liquid include, for example,
Mineral acids such as nitric acid, sulfuric acid, phosphoric acid, citric acid, succinic acid,
Oxalic acid, tartaric acid, acetic acid, malic acid, phytic acid, organic phosphonic acid, p-toluenesulfonic acid, xylenesulfonic acid, and the like. In addition, lithium salts, sodium salts, potassium salts, ammonium salts of these acids, hydroxides, carbonates, hydrogencarbonates of alkali metals, and the like can also be used for the surface conditioning liquid.

Further, to the surface conditioning liquid, 0.0001 to 3% by weight, based on the total weight, of a polymer which is a natural product or a modified or synthetic polymer of the natural product and has a film forming ability is added. You can also. Still further, a preservative, an antifoaming agent, a coloring agent, and the like can be added to the surface conditioning liquid.

As a preferable method for producing a good printing plate using the printing original plate of the present invention, first, an image exposing machine using a high-power laser such as a YAG laser or an infrared semiconductor laser as a light source is used. The printing original is mounted, and digital information from a computer is directly written on the printing original of the present invention to form an image, and then a developing process is performed with a developer to remove a non-image portion. Thereafter, after being washed with water and / or treated with a water-based desensitizing agent, the printing plate can be obtained by drying. The series of development processing steps may, of course, be carried out one by one. However, in practice, it is easy and preferable to use an automatic developing machine capable of continuously performing these steps. At this time, the printing plate precursor of the present invention has a feature that before and after exposure, no special safety light is required, and the work can be normally performed under room light. In addition, in the conventional plate, after writing the image, a heating process was performed before development to form a latent image.
The printing plate precursor of the present invention also has a feature that heat treatment is not required after image writing. The photosensitive composition of the present invention can be used for various uses other than the printing plate.

[0114]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the scope of these examples.

In the following examples, the dry solid content ratio is described by measuring the weight ratio of a sample of about 1 g before and after drying at 130 ° C. for 1 hour. The number average molecular weight was measured by gel / permeation / chromatography (hereinafter abbreviated as GPC) and described in terms of the molecular weight in terms of polystyrene. The acid value was determined by weighing a predetermined amount of a sample solution and titrating with a methanol solution of potassium hydroxide having a known concentration. NCO
(Isocyanate group) content is determined by weighing a predetermined amount of a sample solution, adding a fixed amount of a solution of di-n-butylamine in ethyl acetate having a known concentration in excess of the isocyanate group to be measured, and reacting with isocyanate. n-Butylamine was determined by back titration with an aqueous hydrochloric acid solution of known concentration. The particle size of the resin fine particles was measured with a laser Doppler particle size distribution analyzer Microtrac UPA-150.

<Synthesis Example 1> (Synthesis Example (1) of Acrylic Resin) 400 g of methyl ethyl ketone was charged into a 1-L four-necked flask equipped with a stirrer, a reflux device, a dry nitrogen inlet tube with a thermometer, and a dropping device. The temperature was raised to 80 ° C. 80 g of styrene and 253.4 of methyl methacrylate
A solution in which 4 g, 51.32 g of acrylic acid, 15.24 g of butyl methacrylate, and 8 g of “Perbutyl O” (a polymerization initiator manufactured by NOF Corporation) were mixed well was dropped over 2 hours. After the dropwise addition, stirring was further continued for 15 hours to obtain an acrylic resin having a dry solid content ratio of 49.5%, an acid value of 50.1 and a number average molecular weight of 18,000. Hereinafter, this is referred to as an acrylic resin (1).

<Synthesis Example 2> (Synthesis Example (2) of Acrylic Resin) 400 g of methyl ethyl ketone was charged into a 1 L four-necked flask equipped with a stirrer, a reflux device, a dry nitrogen inlet tube with a thermometer, and a dropping device. The temperature was raised to 80 ° C. 80 g of styrene and 205.92 of methyl methacrylate were added thereto.
g, acrylic acid 41.04 g, butyl acrylate 4
5.04 g, 2-hydroxyethyl methacrylate 28
g, "Perbutyl O" (a polymerization initiator manufactured by NOF Corporation)
A solution in which 8 g was well mixed was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 15 hours, whereby the dry solid content ratio was 49.8%, the acid value was 40.2, and the number average molecular weight was 2
1,000 acrylic resins were obtained. Hereinafter, this is referred to as an acrylic resin (2).

<Synthesis Example 3> (Synthesis Example (1) of Acrylic Aqueous Resin) 100 g of the solution of the acrylic resin (1) was neutralized with 26.7 g of a 1.0 M aqueous sodium hydroxide solution, and water was added dropwise. . The viscosity of the resin solution gradually increased, and the viscosity was remarkably reduced from the time when about 150 g of water was dropped, whereby the phase inversion was completed.
After addition of a further 150 g of water, the resulting dispersion is
The mixture was heated to ° C., and the organic solvent and excess water were removed under reduced pressure and concentrated. Water was added to the concentrated resin solution to adjust the dry solid content ratio to 30%. Hereinafter, this is referred to as an aqueous resin (A). Its average particle size was 0.2 micrometers.

<Synthesis Example 4> (Synthesis Example of Acrylic Aqueous Resin) 100 g of the above acrylic resin (2) solution was neutralized with 26.7 g of a 1.0 M aqueous sodium hydroxide solution, and water was added dropwise. The viscosity of the resin solution gradually increased, and the viscosity was remarkably reduced from the time when about 150 g of water was dropped, whereby the phase inversion was completed. After further adding 150 g of water, the resulting dispersion was heated to 30 ° C., and the organic solvent and excess water were removed under reduced pressure and concentrated. Water is added to the concentrated resin solution to adjust the dry solid content ratio to 30.
%. Hereinafter, this is referred to as an aqueous resin (B). Its average particle size was 0.07 micrometers.

<Synthesis Example 5> (Synthesis Example of Acrylic Cross-Linked Resin Fine Particles) "TETR" was added to 100 g of the acrylic resin (1) solution.
AD-X "(polyglycidyl compound manufactured by Mitsubishi Gas Chemical Co., Ltd.) 0.89 g and 1.0 M aqueous sodium hydroxide solution 2
Water was slowly added dropwise to the well-mixed solution to which 6.7 g was added. The viscosity of the resin solution gradually increased, and the viscosity was remarkably reduced from the time when about 150 g of water was dropped, whereby the phase inversion was completed.
After addition of a further 150 g of water, the resulting dispersion is
C. to remove the organic solvent and excess water under reduced pressure, then heated to 80.degree. C. and stirred for 4 hours. Water was added to adjust the dry solids ratio to 30% to obtain an aqueous acrylic resin solution. Hereinafter, this is referred to as an aqueous resin (C). Its average particle size was 0.25 micrometers.

<Synthesis Example 6> (Synthesis Example of Polyester Resin Fine Particles) Terephthalic acid 397.6 was placed in a 2 L four-necked flask equipped with a stirrer, a rectification tube, a dry nitrogen introduction tube, and a thermometer.
g, 397.6 g of isophthalic acid, ethylene glycol 1
44.9 g and 243.6 g of neopentyl glycol were charged and heated to 160 ° C. After adding 0.5 g of dibutyltin oxide and performing a dehydration reaction while raising the temperature to 260 ° C. over 6 hours, the rectification tube was replaced with a decanter, and 30 g of xylene was added to remove azeotropically water at 260 ° C. Stirring was continued for another 4 hours. After allowing the reaction mixture to cool, it was diluted with 500 g of methyl ethyl ketone to obtain a polyester having an acid value of 19.3 and a dry solid content ratio of 65.5%.

To 100 g of the above polyester solution was added 30 g of methyl ethyl ketone, and 2.36 of triethylamine was added.
Then, water was added dropwise with stirring. The viscosity of the resin solution gradually increased, and the viscosity was remarkably reduced from the time when about 150 g of water was dropped, whereby the phase inversion was completed. After addition of a further 150 g of water, the resulting dispersion is heated to 30 ° C. and the organic solvent and excess water are removed under reduced pressure,
An aqueous polyester resin solution having a dry solid content ratio of 30.0% was obtained. Hereinafter, this is referred to as an aqueous resin (D). Its average particle size was 0.30 micrometers.

<Synthesis Example 7> (Synthesis Example of Urethane Cross-Linked Resin Fine Particles) A 1 L four-necked flask equipped with a stirrer, a reflux unit, a dry nitrogen inlet tube, and a thermometer was charged with "Varnock DN-9".
80 "(polyisocyanate manufactured by Dainippon Ink and Chemicals, Inc.) 533 g, 2,3-bis (hydroxymethyl) propionic acid 33.5 g, dibutyltin dilaurate 0.0
5 g and 300 g of ethyl acetate were added, and stirring was continued at 80 ° C. for 3 hours, whereby the dry solid content ratio was 50.0%,
A solution of a polyurethane prepolymer having an NCO content of 6.80% was obtained.

Solution 10 of the above polyurethane prepolymer
30 g of methyl ethyl ketone was added to 0 g, neutralized with 3.50 g of triethylamine, and water was added dropwise with stirring.
The viscosity of the prepolymer solution gradually increased, and the viscosity was remarkably reduced from the time when about 150 g of water was dropped, whereby the phase inversion was completed.
After further adding 150 g of water, an aqueous solution in which 2.51 g of diethylenetriamine was dissolved in 50 g of water was slowly added while stirring. Next, the obtained dispersion was heated at 30 ° C.
To remove an organic solvent and excess water under reduced pressure to obtain an aqueous urethane solution having a dry solid content ratio of 33.5%. This was further diluted with water to obtain an aqueous urethane solution having a dry solid content ratio of 30%. Hereinafter, this is referred to as an aqueous resin (E). Its average particle size is 0.0
It was 78 micrometers.

<Synthesis Example 8> (Synthesis Example (1) of Alkali-Soluble Crosslinking Agent) In a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, 2- (4,6) was added. -Diamino-1,3,5-triazin-2-yl) benzoic acid (hereinafter abbreviated as BAG) 71.2 g, 374.3% aqueous formaldehyde solution 154.3 g and n-butanol 133.
2 g was charged and heated at 80 ° C. for 30 minutes. Next, the reflux tube was replaced with a decanter, and water was removed over 4 hours while azeotroping water and butanol under reduced pressure. Next, methyl isobutyl ketone (hereinafter abbreviated as MIBK)
100 g was added, and the solvent was removed under reduced pressure to obtain an alkali-soluble crosslinking agent. This was diluted with methyl ethyl ketone (hereinafter abbreviated as MEK) to obtain an alkali-soluble crosslinking agent solution having a dry solid content ratio of 40%. Hereinafter, this is referred to as an alkali-soluble crosslinking agent (a).

<Synthesis Example 9> (Synthesis Example (2) of Alkali-Soluble Crosslinking Agent) In a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, 23.8 g of BAG was added.
2,4-diamino-6-phenyl-1,3,5-triazine (hereinafter abbreviated as benzoguanamine) 18.7
g, 37% aqueous formaldehyde solution 68.6 g and n-
88.8 g of butanol was charged and heated at 80 ° C. for 30 minutes. Next, the reflux tube was replaced with a decanter, and water was removed over 4 hours while azeotroping water and butanol under reduced pressure. Next, 50 g of MIBK was added and the solvent was removed under reduced pressure to obtain an alkali-soluble crosslinking agent.
This was diluted with MEK to obtain an alkali-soluble crosslinking agent solution having a dry solid content ratio of 40%. Hereinafter, this is referred to as an alkali-soluble crosslinking agent (b).

<Synthesis Example 10> (Synthesis Example (3) of Alkali-Soluble Crosslinking Agent) In a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube and a nitrogen inlet tube, 7.1 g of BAG and benzoguanamine 31 were placed. 8.8 g, 68.6 g of a 37% aqueous formaldehyde solution and 88.8 g of n-butanol,
Heat at 80 ° C. for 30 minutes. Next, the reflux tube was replaced with a decanter, and water was removed over 4 hours while azeotroping water and butanol under reduced pressure. Next, 50 g of MIBK was added and the solvent was removed under reduced pressure to obtain an alkali-soluble crosslinking agent. This was diluted with MEK to obtain an alkali-soluble crosslinking agent solution having a dry solid content ratio of 40%. Hereinafter, this is referred to as an alkali-soluble crosslinking agent (c).

<Synthesis Example 11> (Synthesis Example of Alkali-Soluble Crosslinking Agent (4)) Benzoguanamine 3 was placed in a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube.
7.4 g, glyoxylic acid monohydrate 2.8 g, 37% formaldehyde aqueous solution 66.0 g and n-butanol 8
8.8 g was charged and heated at 80 ° C. for 30 minutes. Next, the reflux tube was replaced with a decanter, and water was removed over 4 hours while azeotroping water and butanol under reduced pressure. Next, 50 g of MIBK was added and the solvent was removed under reduced pressure to obtain an alkali-soluble crosslinking agent. This is ME
After dilution with K, an alkali-soluble crosslinking agent solution having a dry solid content ratio of 40% was obtained. Hereinafter, this is referred to as an alkali-soluble crosslinking agent (d).

<Synthesis Example 12> (Synthesis Example (5) of Alkali-Soluble Crosslinking Agent) In a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube and a nitrogen inlet tube, 25.2 g of melamine was added.
Glyoxylic acid monohydrate 3.0 g, 37% aqueous formaldehyde solution 100.3 g and n-butanol 118.4
g was heated at 80 ° C. for 30 minutes. Next, the reflux tube was replaced with a decanter, and water was removed over 4 hours while azeotroping water and butanol under reduced pressure. Then, MIB
An alkali-soluble crosslinking agent was obtained by adding 50 g of K and removing the solvent under reduced pressure. This was diluted with MEK to obtain an alkali-soluble crosslinking agent solution having a dry solid content ratio of 40%. Hereinafter, this is referred to as an alkali-soluble crosslinking agent (e).

<Synthesis Example 13> (Synthesis example of polymethyl methacrylate fine particles) 200 g of water and New were placed in a 500 mL four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube.
col-560SF (Emulsifier manufactured by Japan Emulsifier Co., Ltd.)
0.2 g and 0.2 g of methyl methacrylate
Stirred at 0 ° C. for 30 minutes. Next, a mixture of 100 g of methyl methacrylate and 0.8 g of Newcol-560SF was added dropwise over 2 hours, followed by stirring at 80 ° C. for 6 hours. This was diluted with water to obtain an aqueous dispersion of polymethyl methacrylate fine particles (F) having an average particle diameter of 0.1 μm and a dry solid content ratio of 20%.

<Example 1> 40 g of the aqueous dispersion (A) of the acrylic water-based resin obtained in Synthesis Example 3, "Carbon Black MA-100" (carbon black manufactured by Mitsubishi Chemical Corporation)
3 g, 37 g of water and 20 g of isopropyl alcohol were mixed well, and 180 g of 1 mm glass beads were added thereto.
The mixture was dispersed for 1 hour with a paint conditioner. By filtering off the glass beads, an acrylic fine particle solution in which carbon black was dispersed was obtained. This solution 20
g of the alkali-soluble crosslinking agent (a) obtained in Synthesis Example 8
88 g, 1 M aqueous sodium hydroxide solution 1.6 g, water 3
g and 10 g of isopropyl alcohol to give a coating solution.

B4 Wide-sized aluminum plate having a thickness of 0.3 mm was grained with a nylon brush and a 400-mesh aqueous suspension of pumicestone, and then subjected to current density in a 20% sulfuric acid electrolyte. After anodizing treatment at 2 A / dm ² to form an oxide film of 2.7 g / m ² ,
After washing with water and drying, a support was obtained.

The above coating solution was applied to this support using a No. 14 bar coater and dried at 60 ° C. for 4 minutes.
A printing plate precursor of the present invention was obtained.

Using this printing plate precursor, a test exposure machine (wavelength 808 nm, output 1) equipped with a near-infrared semiconductor laser
W, manufactured by Line Electronics Co., Ltd.) while changing the irradiation amount. Laser aperture is one of intensity at peak
/ E ² was 20 μm. After image exposure, positive PS plate developer "PD-1" (manufactured by Polychrome Japan Co., Ltd.)
It was immersed in a 1:99 diluted solution at 30 ° C. for 30 seconds to perform development, washed with water, and dried. Its sensitivity was 200 mJ / cm ² , and the non-image area was peeled off cleanly. The sensitivity after the accelerated storage stability test after heating the printing plate precursor at 60 ° C. for 15 hours did not change, and no stain on the non-image area was observed. Furthermore, the printing plate precursor was heated at 60 ° C for 7 minutes.
In the accelerated storage stability test exposed for 15 hours under a humidity of 5%, there was no change in the developability, and no stain on the non-image area was observed.

<Examples 2 to 9> A printing plate precursor was prepared in the same manner as in Example 1 except that the aqueous resin and the alkali-soluble crosslinking agent were changed to the materials shown in Table 1. The same evaluation was performed, and the results are summarized in Table 2.

(Example 10) To 100 g of the above-mentioned acrylic resin (1) solution, 2.5 g of "YKR-3070" (an infrared absorbing dye manufactured by Yamamoto Kasei Co., Ltd.) was added and mixed well. The mixture was neutralized with 26.7 g of a 1.0 M aqueous sodium hydroxide solution, and water was added dropwise. The resin solution gradually thickens,
From about the time when about 150 g of water was dropped, the viscosity was remarkably lowered and the phase inversion was completed. After further adding 150 g of water, the resulting dispersion was heated to 30 ° C. to remove the organic solvent and excess water under reduced pressure. After concentration, water was added to obtain an aqueous dispersion having a dry solid content ratio of 30%. The average particle size of this is
0.2 micrometers.

10 g of this aqueous dispersion was added to a mixed solution consisting of 1.88 g of an alkali-soluble crosslinking agent (c), 0.3 g of a 1 molar NaOH aqueous solution, 50 g of water and 15 g of isopropyl alcohol to prepare a coating solution. The coating solution was applied to the support obtained in the same process as in Example 1 using a No. 14 bar coater, and dried at 60 ° C. for 4 minutes to obtain a printing plate precursor of the present invention.

Using this printing plate precursor, a test exposure machine (wavelength 808 nm, output 1) equipped with a near-infrared semiconductor laser
W, manufactured by Line Electronics Co., Ltd.) while changing the irradiation amount. After image exposure, a positive PS plate developer "PD
-1 "(manufactured by Polychrome Japan Ltd.) was immersed in a 1:99 diluted solution at 30 ° C. for 30 seconds for development, washed with water, and dried. The sensitivity is 200
mJ / cm ² , and the non-image area was peeled off cleanly. There was no change in the developability after the accelerated storage stability test after heating the printing plate precursor at 60 ° C. for 15 hours, and no stain on the non-image area was observed. Further, in the accelerated storage stability test in which the printing plate precursor was exposed at 60 ° C. under a humidity of 75% for 15 hours, there was no change in the sensitivity and no stain on the non-image area was observed.

(Comparative Example 1) 24 g of the acrylic resin (1) obtained in Synthesis Example 1, 3 g of "MA-100" (carbon black manufactured by Mitsubishi Chemical Corporation) and 23 g of methyl ethyl ketone were mixed well, and 1 mm was added thereto. Add 90g of glass beads,
The mixture was dispersed for 1 hour with a paint conditioner. By filtering and removing the glass beads, an acrylic resin solution in which carbon black was dispersed was obtained. 10 g of this solution
And 1.88 g of an alkali-soluble crosslinking agent (a) were mixed well and diluted with 50 g of methyl ethyl ketone to obtain a coating solution. This coating solution was applied to the support obtained in the same process as in Example 1 using a No. 20 bar coater,
For 4 minutes to obtain a printing plate precursor. The dry coating amount was 2.0 g / m ² . This printing plate precursor was used as a positive PS plate developer "PD-1" (Polychrome Japan Co., Ltd.)
Was immersed at 30 ° C. for 30 seconds using a 1: 9 diluted solution of the above, but did not peel off.

(Comparative Example 2) 24 g of the acrylic resin (2) obtained in Synthesis Example 2, 3 g of "MA-100" (carbon black manufactured by Mitsubishi Chemical Corporation) and 23 g of methyl ethyl ketone were mixed well, and 1 mm was added thereto. Add 90g of glass beads,
The mixture was dispersed for 1 hour with a paint conditioner. By filtering and removing the glass beads, an acrylic resin solution in which carbon black was dispersed was obtained. 10 g of this solution
And 1.88 g of an alkali-soluble crosslinking agent (a) were thoroughly mixed, and diluted with 50 g of methyl ethyl ketone to obtain a coating solution. After applying this coating solution to the support obtained in the same process as in Example 1 using a No. 20 bar coater,
For 4 minutes to obtain a printing plate precursor. The dry coating amount was 2.0 g / m ² .

Using this printing plate precursor, a test exposure machine (wavelength 808 nm, output 1) equipped with a near-infrared semiconductor laser
(W, manufactured by Line Electronics Co., Ltd.) while changing the irradiation amount. After image exposure, a positive PS plate developer "PD-
Using a 1:99 diluted solution of "1" (manufactured by Polychrome Japan Co., Ltd.), the film was immersed at 30.degree. C. for 30 seconds to perform development. This product did not peel off both the image area and the non-image area, and could not form an image. Further, a developer "PD-1" (Polychrome Japan Co., Ltd.)
Developing was carried out by immersing in a 1: 9 diluted solution of (1) at 30 ° C. for 30 seconds, but image formation was not possible.

Comparative Example 3 10.8 g of an aqueous dispersion of the polymethyl methacrylate fine particles (F) obtained in Synthesis Example 13
In addition, 3.4 g of “CW-1” (carbon black aqueous dispersion manufactured by Orient Chemical Co., Ltd., dry solid content ratio: 20%), 60.9 g of water, and Kuraray Povar PVA-120
25 g of a 2% aqueous solution of (polyvinyl alcohol manufactured by Kuraray Co., Ltd.), "Nikarac MW-30" (Sanwa Chemical)
2.5 g of a 1% aqueous solution of methylated melamine (manufactured by K.K.) was well mixed. The coating solution was applied to the support obtained in the same process as in Example 9 using a No. 32 bar coater, and dried at 35 ° C. for 24 hours to obtain a printing plate precursor. The dry coating amount was 2.0 g / m ² .

Using this printing plate precursor, a test exposure machine (wavelength 808 nm, output 1) equipped with a near-infrared semiconductor laser
W, manufactured by Line Electronics Co., Ltd.) while changing the irradiation amount. After image exposure, development was carried out by immersion in a mixture of water and IPA (weight ratio 1/9) at 30 ° C. for 30 seconds, followed by washing with water and drying. Its sensitivity was 1,000 mJ / cm ² . After the accelerated storage stability test after heating the printing plate precursor at 60 ° C. for 15 hours, development was not possible with the above-mentioned developer comprising a mixture of water and IPA, and a change in sensitivity was clearly observed.

(Printing test) The printing plate precursors obtained in Examples 1 to 10 were subjected to a test exposure machine (wavelength: 808 nm, output: 1 W, manufactured by Line Electronics Co., Ltd.), and the sensitivity required by each printing plate precursor. An image was written with the energy amount of, and then developed under the same conditions as in the example, washed with water and dried to obtain a printing plate.

The printing plates thus obtained were each mounted on a printing machine (TOKO 820L: manufactured by Tokyo Aviation Instruments Co., Ltd.), and a printing test was performed. As printing conditions, printing speed: 3,000 sheets / hour, printing paper: Jujo Diamond Coat B4, ink: GEOS-G Beni S (manufactured by Dainippon Ink and Chemicals, Inc.), dampening solution: NA108W (1:50) Table 2 summarizes the results of printing tests performed on 6,000 sheets under dilution (manufactured by Dainippon Ink and Chemicals, Inc.). Each of the obtained 6,000 prints was a good print without any problems such as quality. Further, after burning at 230 ° C. for 20 minutes, a printing test was similarly performed.
20,000 sheets with no problem in quality were obtained, and no damage was observed on the plate surface.

The printing plate precursor obtained in Comparative Example 3 was subjected to a printing test in the same manner as described above. In the printing plate precursor obtained in Comparative Example 3, up to 6,000 sheets of the obtained printed material were good prints without any problem of quality or the like. However, the printing plate obtained from this printing plate precursor was 230 After printing at 20 ° C. for 20 minutes, the printing plate had stains on the printed matter after about 15,000 sheets. These results are also shown in Table 2.

[0147]

[Table 1]

[0148]

[Table 2]

[0149]

Since the photosensitive composition of the present invention uses an alkali-soluble crosslinking agent together with an aqueous resin, a photosensitive layer having good storage stability can be provided. The printing plate precursor having a photosensitive layer composed of the photosensitive composition of the present invention can be plate-made without preheating after laser writing, has good sensitivity, and further has printing durability by burning if necessary. A printing plate with excellent properties can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 101/02 C08L 101/14 101/14 G03F 7/00 503 G03F 7/00 503 7/038 505 7 / 038 505 B41M 5/26 T (72) Inventor Katsuharu Takahashi 5-21-2 Someno, Sakura City, Chiba Prefecture (72) Inventor Yasuhiko Kojima 1-14-3-403, Akamidai, Konosu City, Saitama Prefecture (72) Inventor Koji Oe 5-90-2-505 Higashima, Kitamoto City, Saitama Prefecture

Claims (7)

[Claims] 1. A photosensitive composition comprising an alkali-soluble crosslinking agent, an aqueous resin having a functional group capable of undergoing a crosslinking reaction with the crosslinking agent, and an infrared absorber. 2. The photosensitive composition according to claim 1, wherein the alkali-soluble crosslinking agent is an amino compound or an amino resin. 3. The photosensitive composition according to claim 1, wherein the aqueous resin is a resin fine particle dispersion. 4. The photosensitive composition according to claim 1, wherein the resin fine particles are crosslinked resin fine particles. 5. The method according to claim 1, wherein the support is provided on a support.
13. A printing plate precursor comprising a photosensitive layer comprising the composition described in any one of the above items. 6. The photosensitive layer of the printing plate precursor according to claim 5,
An image forming method, comprising: forming an image using a laser beam; and developing the image using a basic aqueous solution or water. 7. The image forming method according to claim 6, wherein a laser beam having a maximum intensity in a range of 760 to 3,000 nm is used.