JPH06250384A - Photosensitive resin composition for planographic printing - Google Patents

Abstract

PURPOSE:To obtain a photosensitive resin compsn. for planographic printing having high sensitivity and high stability and containing a new diazo resin having a wide range of dissolution in a solvent by incorporating a photosensitive diazo resin contaiing a specified photopolymn. initiator as the counter anion for the diazonium group. CONSTITUTION:This photosensitive resin compsn. for planographic printing containing a photosensitive diazo resin contains a photopolymn. initiator having anion groups in the molecule as the counter anion for the diazonium group. This photosensitive resin compsn. has high sensitivity for active energy rays, so that an image can be formed even with a small exposure. Or, an image can be formed with a little amt. of diazo resin used. The diazo resin and the photosensitive compsn. are stable for a long time at room temp. or under conditions of a high humidity and high temp., and cause no deterioration such as decomposition or crosslinking. Further, the resin has a wide range of solubility in solvents to be used for formation of films.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive resin composition for lithographic printing. In particular, it relates to a photosensitive diazo resin composition for a negative plate material.

[0002]

2. Description of the Related Art A lithographic printing plate is generally a plate in which a photosensitive resin composition layer containing a photosensitive resin and a solvent-soluble binder resin as main components is formed on a support such as an aluminum plate. It is a material. Such a plate material is exposed through a photographic image such as a negative, and the unexposed portion of the photosensitive resin composition layer is removed by elution with a developer, and the exposed insolubilized portion is left as an image area. As a result, a lithographic printing plate can be obtained.

The planographic printing plate material is widely used as an offset printing plate material because the plate making process is short and the plate making operation is easy. Therefore, it is possible to provide a printing plate having good image forming properties, storage stability and developability, and excellent printing durability, and there is a great demand for an inexpensive lithographic printing plate or photosensitive resin composition. large.

The photosensitive resin used for preparing the lithographic printing plate and the photosensitive resin composition having such excellent properties are generally required to have the following characteristics.

(1) High sensitivity, that is, high sensitivity to various active energy rays and the ability to form an image even with a small exposure amount.

(2) Stability, that is, no reaction such as decomposition or crosslinking occurs even if it is stored at room temperature or under conditions of high temperature and high humidity for a long time.

(3) Solvent solubility, that is, good solubility in a developer containing no harmful solvent such as DMF and methyl cellosolve.

Since the diazo resin satisfies such characteristics relatively well, it is widely used as a photosensitive resin for a lithographic printing plate. The diazo resin is a resin having a diazonium salt. Currently, resins obtained by reacting a polycondensation reaction product of p-diazodiphenylamine and formaldehyde with an inorganic or organic coupling agent are mainly used as photosensitive resins for lithographic printing plate.

Conventionally, in order to further improve the printing characteristics of diazo resins, in particular the sensitivity, stability and solvent solubility,
Various attempts have been made.

As an attempt to increase the sensitivity of the diazo resin, for example, JP-A-54-30121 describes a diazonium compound having a polyester main chain. However, in order to prepare a diazo resin from such a diazonium compound, it is necessary to use a toxic compound such as trifluoroacetic acid as a solvent, which requires a long reaction step at high temperature. Therefore, such a method is not practical.

JP-A-58-062641 describes a method for preparing a diazo resin by synthesizing a prepolymer from acetylaminoaniline and the like and diazotizing the prepolymer. Further, JP-A-58-187925 describes the synthesis of a diazo resin by reacting a diazonium compound with a vinyl ester compound. However, these methods have many synthetic steps, are complicated, and are not practical. Further, since such a diazo resin is poor in solvent solubility, the developability of the obtained photosensitive plate is poor.

JP-A-61-273538 discloses that a diazonium compound having a hydroxyl group is esterified, bound to a carboxylic acid-containing compound, and then esterified with a styrene / maleic anhydride copolymer at room temperature for 3 hours. The diazo resins obtained according to US Pat. However, since the sensitivity is not sufficiently improved, the image forming property of the obtained photosensitive plate is poor.

These conventional diazo resins generally have about
It has high photosensitivity to light with wavelengths of 220 to 400 nm,
The sensitivity to visible light having a wavelength of about 400 nm or more is not sufficient. Therefore, when visible light is used during exposure, only a part of the irradiation light is used, and sufficient sensitivity cannot be obtained.

In order to improve the stability of the diazo resin, attempts have been made to improve the water-insolubility and lipophilicity of the diazo resin by coupling the water-soluble diazo resin with an inorganic compound. JP-A-47-1167 describes the coupling of a water-soluble diazo resin with an acidic aromatic compound, or the coupling of a water-soluble diazo resin with a phenolic hydroxyl group-containing aromatic compound. However, the resins obtained by these methods are glycols,
Since the solubility in ether, alcohol and ketone is poor, the developability of the photosensitive plate becomes poor. Further, the sulfonic acid or sulfonate having a long chain alkyl group used here is difficult to manufacture because it precipitates in the form of a gum during synthesis.

The use of water-insoluble, organic solvent-soluble counter anions has also been attempted. In JP-A-54-98613, the BF
Halogenated Lewis acids such as ₄ and PF ₆ are used, and in JP-A-56-121031, perhalogenic acid, perchloric acid and periodic acid are used. However, the resins obtained by these methods have insufficient solvent solubility. Therefore, the developability of the photosensitive plate becomes poor,
The diazo resin remains on the non-image areas even after development, and stains occur during printing.

JP-A-59-38746 describes an attempt to use an organic coupling agent and an inorganic coupling agent in combination. However, the resins obtained by these methods have extremely poor solubility in alkaline developers. Therefore, the developability of the photosensitive plate becomes poor, the diazo resin remains in the non-image area even after development, and stains are generated during printing.

Further, JP-A-62-175731 describes a combination of two kinds of organic sulfonic acids having a basic unit number of 2.5 or more, and JP-A-60-97350 discloses a counter anion. The use of sulfopolyesters is described. According to such a method, although the stability of the obtained diazo resin is improved, the reactivity of the diazo resin is lowered, and thus the image formability is substantially insufficient.

As a conventional attempt for improving the solubility of a diazo resin in a solvent, for example, JP-A-1-102456 describes a cocondensation product of an aromatic compound having a phenolic hydroxyl group and an aromatic diazonium compound. Has been done. JP-A-1-102457 describes a cocondensate of an aromatic compound having at least one of a carboxyl group and a hydroxyl group and an aromatic diazonium compound. Also,
JP-A-1-245246 describes a cocondensation product of an aromatic compound having a sulfonic acid group, a sulfinic acid group and phenylene or naphthylene containing a salt thereof, and an aromatic diazonium compound. However, when these resin compositions are used, the durability of the printing plate obtained is insufficient. Further, as a method for solving the problems of the diazo resin by reducing the amount of the diazo resin as much as possible, the binder resin and the diazo resin are further mixed with a photopolymerizable monomer or oligomer and a photopolymerization initiator. Attempts have been made to add it. In this method, a reaction between a diazo resin and a binder resin, and a reaction between a monomer and an oligomer occur to form a composite curing system, but there are problems of stability of the initiator, sensitivity, and solubility in a developer,
It is difficult to balance plate making properties and plate performance as a printing plate material.

[0019]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object thereof is to:
It has high sensitivity and the crosslinking efficiency at the time of light irradiation is improved.
To provide a photosensitive resin composition for lithographic printing containing a novel diazo resin which has sensitivity to irradiation light having a wavelength of 400 nm or more, has good stability, and has a wide dissolution range in a solvent. It is in.

[0020]

The present invention provides a photosensitive resin composition for lithographic printing containing a photosensitive diazo resin, which contains a photopolymerization initiator having an anion group in the molecule as a counter anion of a diazonium group. By that, the above-mentioned object is achieved.

The photosensitive diazo resin that can be used in the photosensitive resin composition of the present invention uses a photopolymerization initiator containing an anion group as the counter anion of the diazonium group of the diazonium group-containing resin well known to those skilled in the art. is there.

The aromatic diazonium compound is not particularly limited, but is preferably a phenyl or naphthalene derivative which also has an anion group, a hydroxyl group, an amino group and / or a quaternary ammonium group as the case requires, for example, 4-diazo.
-4'-methoxydiphenylamine hexafluorophosphate, 4-diazo-4'-methoxydiphenylamine hydrogensulfate, 4-diazo-4'-ethoxydiphenylamine hexafluorophosphate, 4-
Diazo-4'-propoxydiphenylamine tetrafluoroborate, 4-diazo-3-methoxydiphenylamine hexafluorophosphate, 4-diazo-3-methoxydiphenylamine tetrafluoroborate, 4-diazo-diphenylamine 6 Examples thereof include fluorophosphate and 4-diazodiphenylamine hydrogensulfate. Particularly preferred aromatic diazonium compounds are amine hydrogen sulfates such as 4-diazo-4'-methoxydiphenylamine, 4-diazo-4'-ethoxydiphenylamine and 4-diazo-3-methoxydiphenylamine and 4-diazo-diphenylamine. Is mentioned.

Examples of the active carbonyl compound that can be used as the polycondensation reaction cross-linking agent include aldehydes such as paraformaldehyde, formaldehyde, acetaldehyde, butyraldehyde and benzaldehyde; ketones such as acetone and acetophenone; vinyl compounds; vinyl ester compounds; Vinyl ether compounds; and their sulfur derivatives. Further, alkoxy compounds such as bis-methoxymethyldiphenylene oxide and 4,4'-bis-methoxymethyldiphenylmethane can be mentioned.

The reactions for preparing diazo resins are well known to those skilled in the art. For example, Photographic Science and Engineering (Photo. Sci. Eng.) No. 17
Vol., Page 33 (1973), or British Patent No. 1312725.

In that case, an aromatic diazonium compound and an active carbonyl compound are subjected to a polycondensation reaction in sulfuric acid, phosphoric acid, hydrochloric acid or methanesulfonic acid under atmospheric pressure at 5 to 70 ° C. for 30 minutes to 72 hours, A diazo resin is obtained.

The molecular weight of the obtained diazo resin changes depending on the ratio of the number of moles of the aromatic diazonium compound to the number of moles of the active carbonyl compound added, the reaction temperature and the reaction time. Usually, aromatic diazonium compound / active carbonyl compound = 0.6 to 1.5 / 1, preferably 0.7 to 1.4
It is done at / 1. The weight average molecular weight of the diazo resin thus obtained is 400 to 50,000, preferably 600 to 20,00.
The range is 0, and more preferably 800 to 5,500.

The photopolymerization initiator which can be used in the photosensitive resin composition of the present invention is a photopolymerization initiator having at least one anionic group such as sulfonic acid group, carboxyl group and phosphoric acid group, or salts thereof in the molecule. It is an initiator. Examples of such a photopolymerization initiator include benzophenones, specifically, the formula:

[0028]

[Chemical 1] (Where, n = 1~3, R = -S -CH 3) those represented by the representative examples as 4- (sulfomethylated) benzophenone sodium salt; benzils, specifically formula:

[0029]

[Chemical 2] (Where, n = 1~3, R = -S -CH 3) those represented by the representative examples as 4- (sulfomethylated) benzyl sodium salt; xanthones, specifically formula:

[0030]

[Chemical 3] (In the formula, n = 1 to 3), as a representative example, 2- (3-sulfopropoxy) thioxanthone sodium salt; benzoins, specifically, the formula:

[0031]

[Chemical 4] (In the formula, R = H or OR ', R' = H, CH ₃ or C _{2
H 5, R "= - S} -CH 3) at those represented; anthraquinones, specifically formula:

[0032]

[Chemical 5] (In the formula, R = H or —SO ₃ ^— · Na), and a typical example thereof is anthraquinone-1,5-disulfonic acid sodium salt.

Particularly preferable polymerization initiators are anthraquinones and xanthones.

By adding such a photopolymerization initiator to the diazo resin prepared as described above, an exchange reaction of a counter anion occurs. As a result, the diazo resin of the present invention containing a photopolymerization initiator as the counter anion of the diazonium group is deposited. The amount of the dye added varies depending on the type of photopolymerization initiator used and the diazo group equivalent of the diazo resin. Generally, the diazo group of the diazo resin and the anion group of the photopolymerization initiator are used in a range of 100/2 to 120, preferably 100/20 to 100 when expressed in molar concentration.

In the diazo resin of the present invention, various compounds are used as counter anions in combination with the above photopolymerization initiator. The compound obtained as such a counter anion includes an organic acid, an organic acid salt, an inorganic acid and the like.

Examples of the organic acid and organic acid salt that can be used as the counter anion include compounds having the skeleton listed in i) below and the acid group listed in ii) below. i) benzene,
Aromatic skeletons such as toluene, naphthalene and benzophenone, and aliphatic skeletons such as the polymers and sulfonated polymers described in JP 5700542. i
i) carboxylic acid, decanoic acid, phosphonic acid, phosphinic acid,
Phenylphosphoric acid and sulfonic acid.

Specific examples include organic acids and acid salts such as paratoluenesulfonic acid, mesitylenesulfonic acid, naphthalenesulfonic acid and dodecylbenzenesulfonic acid, and their sodium salts and potassium salts.

Examples of inorganic acids which can be used as counter anions include halogenated Lewis acids such as PF ₆ and BF ₄ , and perhalogen acids such as ClO ₄ and IO ₄ .

Polymers having a hydroxyl group-containing aromatic compound such as phenolic acid and a carboxyl group or an acid anhydride group can also be used as the counter anion.

Preferred counter anions are p-toluenesulfonic acid, mesitylenesulfonic acid, dodecylbenzenesulfonic acid, 2-methoxy-4-hydroxybenzophenone-
Examples include 5-sulfonic acid, PF ₆ and BF ₄ .

When a counter anion other than such an anion group-containing photopolymerization initiator is used in combination, first, the anion group-containing photopolymerization initiator is added to the diazo resin, and then the other counter anion is added to perform anion exchange. May be done,
You may add both anionic compounds simultaneously and perform anion exchange. The anionic group-containing photopolymerization initiator and the other counter anion are used in a molar ratio of 100 to 2/0.
It is preferably in the range of 98.

The diazo resin of the present invention alone can be polymerized by a photopolymerization reaction by irradiation with light to form an image. However, in consideration of cost, physical properties of film, workability, etc., it is preferable to use it as a photosensitive resin composition in combination with a binder resin forming a matrix of a printing plate. Such a binder resin is not particularly limited as long as it has good solvent solubility, and may have reactivity with a diazo resin. For example, PVA
A water-developable photosensitive resin composition is prepared by containing such a water-soluble resin.

Examples of the binder resin that can be used in the photosensitive resin composition of the present invention include acrylic resin, polyester resin, alkyd resin, phenol resin, epoxy resin, polyvinyl resin, polyurethane resin, polyether resin, polyamide resin, polyurethane. Examples thereof include resins and modified resins thereof. A resin having solubility and dispersibility in water or an aqueous alkali solution is preferable, and an acrylic resin soluble in an aqueous alkali solution and a phenol resin are particularly preferable. You may use such binder resin in combination of 2 or more types.

A preferred alkaline aqueous solution-soluble acrylic resin has, for example, an acid value of 10 to 150, a hydroxyl value of 0 to 250, and a molecular weight.
2,000 to 500,000 acrylic resins can be mentioned. More preferably, the acid value is 10-40, the hydroxyl value is 40-200, and the molecular weight is 5,000-4.
It is 0,000 acrylic resin. The resin itself may contain a photosensitive group.

These acrylic resins are acrylic polymers normally used in the paint industry. Further, such an acrylic resin is obtained by homopolymerizing an ester monomer of acrylic acid or methacrylic acid or by copolymerizing these with another ethylenically unsaturated monomer. Such a polymerization operation is performed by a method well known to those skilled in the art. As a preferred example, Japanese Patent Application No. 3-20919 describes a polymerization initiator, a solvent and reaction conditions which can be used for polymerization.

The monomers that can be used to prepare the preferred acrylic resins are listed below.

(I) Acid group-containing monomer: for example, acrylic acid,
Methacrylic acid, crotonic acid itaconic acid, maleic acid, maleic anhydride, fumaric acid, sodium vinyl sulfonate, sodium styrene-p-sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, 2-amidophosphoxyethyl methacrylate;

(II) Hydroxyl group-containing monomer: eg 2-
Hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methallyl alcohol, N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl ) Methacrylamide, o-, m-, p-hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or -methacrylate;

(III) Alkyl acrylates or methacrylates: eg methyl (meth) acrylate, ethyl
(Meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, acyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl acrylate, 2-chloroethyl acrylate;

(IV) Polymerizable amide: for example, acrylamide, methacrylamide, N-methylol acrylamide,
Acrylamide such as N-methylolmethacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylamide, N-ethyl-N-phenylacrylamide, etc. Methacrylamides;

(V) Nitrogen-containing alkyl acrylate or methacrylate: for example, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylic acid acid;

(VI) Vinyl ethers: For example, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether;

(VII) Vinyl esters: for example, vinyl acetate, vinyl chloroacetate, vinyl butyrate,
Vinyl benzoate;

(VIII) Styrenes: for example, styrene, α-methylstyrene, methylstyrene, chloromethylstyrene;

(IX) Vinyl ketones: for example, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone,
Phenyl vinyl ketone;

(X) olefins: for example, ethylene, propylene, isobutylene, butadiene, isoprene;

(XI) glycidyl (meth) acrylate;

(XII) Polymerizable nitrile: for example, acrylonitrile, methacrylonitrile;

(XIII) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine;

(XIV) Zwitterionic monomer: N, N-dimethyl-N
-Methacryloxyethyl-N- (3-sulfopropyl) -ammonium-betaine, N, N-dimethyl-N-methacrylamidopropyl-N- (3-sulfopropyl) -ammonium-betaine, 1- (3-sulfopropyl ) -2-Vinylpyridinium-betaine;

(XV) A compound obtained by reacting a compound having a functional group which chemically reacts with the above-mentioned monomer: for example, a monomer produced by the reaction of the hydroxyl group-containing monomer (II) and an isocyanate compound, or a carboxyl group-containing monomer. Monomers produced by reaction of the monomer (I) with a glycidyl group-containing compound.

In the present invention, other binder resins which are preferable to be blended with the diazo resin include alkali-soluble novolac resins. Specifically, phenol formaldehyde resin, cresol formaldehyde resin,
Examples include pt-butylphenol formaldehyde resin, phenol-modified xylene resin, and phenol-modified xylene mesitylene resin. Other useful alkali-soluble resins also include polyhydroxystyrenes, polyhalogenated hydroxystyrenes, copolymers of (meth) acrylic acid with other vinyl compounds (eg, methylmethacrylate), and the like. Furthermore, if necessary, polyvinyl butyral resin, polyurethane resin, polyamide resin, polystyrene-maleic acid resin, epoxy resin, natural resin and their modified resins and water-solubilized modified resins are used.

Further, in the present invention, a compound having at least one photopolymerizable or photoreactive group in the molecule may also be used. They may be in the form of monomers, oligomers or polymers, but monofunctional and polyfunctional monomers are utilized.

An ethylenically unsaturated monomer is often used as the compound having a photopolymerizable group. The photopolymerizable ethylenically unsaturated monomer imparts higher durability to the printing plate. Examples of such a monomer include a compound having an ethylenically unsaturated group, and preferably a polyfunctional monomer is included. The use of the polyfunctional monomer in the resin system of the present invention imparts durability to the printing plate, but does not impair the developability of the resin plate with an alkaline developer. As the monomer, a monofunctional monomer or a polyfunctional monomer having good compatibility with a resin system (for example, those in the following specific examples or those described in US Pat. No. 3,801,328) may be used. Butyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methallyl alcohol, N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o
-, M-, p-hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or -methacrylate, alkyl acrylate or methacrylate: for example methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth). Acrylate, propyl (meth)
Acrylate, acyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl acrylate, 2-
Chloroethyl acrylate, polymerizable amide: for example, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-hexyl acrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl. Acrylamide such as acrylamide, N-nitrophenylacrylamide, N-ethyl-phenylacrylamide, or methacrylamide, nitrogen-containing alkyl acrylate or methacrylate: for example, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, vinyl ethers: for example, ethyl vinyl ether, 2-chloro Ethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether Ether, octyl vinyl ether, phenyl vinyl ether, vinyl esters: for example vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate, styrenes:
For example, styrene, α-methylstyrene, methylstyrene, chloromethylstyrene, vinyl ketones: for example, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, olefins: for example, glycidyl (meth) acrylate, polymerizable nitrile:
For example, acrylonitrile, methacrylonitrile, N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, zwitterionic monomers: such as N, N-dimethyl-N.
-Methacryloxyethyl-N- (3-sulfopropyl) ammonium-betaine, N, N-dimethyl-N-methacrylamidopropyl-N- (3-sulfopropyl) -ammonium-betaine, 1- (3-sulfopropyl) -2-Vinylpyridinium-betaine, monomer having sulfonic acid group, phosphoric acid group: vinyl sulfonic acid, 2-acrylamide-2
Compounds obtained by reacting a compound having a functional group that chemically reacts with methylpropane sulfonic acid and any of the above monomers: for example, a reaction product monomer of the above hydroxyl group-containing monomer and an isocyanate compound, a carboxyl group-containing monomer And a glycidyl group-containing compound produced by reaction, and other monomers shown in Japanese Patent Application No. 3-36029. One or more of the compounds exemplified above may be included.

Examples of polyfunctional monomers are trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene,
Ethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triethylene Glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2,2-bis [4- (methacryloxy polyethoxy) phenyl] propane, 1,3-butylene glycol di (meth ) Acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol di (meth) acrylate, glycerol allyloxydi (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) Acrylate, 1,1,1-to Lishydroxymethylethane tri (meth) acrylate, 1,1,1
-Trishydroxymethylpropane di (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate, etc. Can be mentioned. Further, if necessary, a combination of two kinds of monomers having an ethylenically unsaturated group each having a group having mutual reactivity is possible. For example, glycidyl acrylate, an ethylenically unsaturated monomer containing an ethoxy group such as glycidyl methacrylate, and a carboxyl group-containing ethylenically unsaturated monomer such as acrylic acid, methacrylic acid, and crotonic acid are the most representative ones. The mutually reactive groups are not limited to these, and examples thereof include amine and carbonyl, epoxide and carboxylic acid anhydride, amine and carboxylic acid chloride, alkyleneimine and carbonyl, organoalkoxysilane and carboxyl, and hydroxyl. Various substances such as isocyanato have been proposed and can be used.

Specific examples of preferable monomers used in the present invention include unsaturated carboxylic acid esters [for example, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl.
(Meth) acrylate, polyethylene glycol mono (meth) acrylate, methoxy polyethylene glycol mono (meth) acrylate, polypropylene glycol mono
(Meth) acrylate, phenoxy polyethylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate,
Methoxy polyethylene glycol di (meth) acrylate, polypropylene di (meth) acrylate, diallyl itaconate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4- Cyclohexanediol di (meth) acrylate, 1,2,4-butanetriol tri (meth) acrylate, glycerol polypropylene glycol tri (meth) acrylate, 1,4-benzenediol di (meth) acrylate, pentaerythritol tetra (meth) acrylate , Tetramethylene glycol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc.], unsaturated amide [eg, methylenebis (meth) acrylamide, ethylenebis] (Meta) Riruamido, 1,6-hexamethylene bis (meth) acrylamide,
Diethylenetriamine tris (meth) acrylamide, N
-(Hydroxymethyl) acrylamide, N- (hydroxymethyl) methacrylamide, N- (β-hydroxyethyl)
Acrylamide, N- (β-hydroxyethyl) methacrylamide, N, N-bis (β-hydroxyethyl) acrylamide, N, N-bis (β-hydroxyethyl) methacrylamide, etc.], divinyl ester [eg, divinyl adipate, Divinyl phthalate), etc.], acrylated or methacrylated urethane (these are derived from, for example, a hydroxyalkyl acrylate or hydroxyalkyl methacrylate and an isocyanate compound), a diacrylic or dimethacrylic ester, or an aromatic compound and a polyalcohol [eg bisphenol. Or a diepoxy polyether derived from a novolac compound], and further polyester mono / di (meth) acrylate,
Also included are polyether mono / di (meth) acrylates. One or more of these compounds are used,
Generally, water-soluble or water-dispersible monomers are preferred.

The photosensitive composition of the present invention comprises the binder resin and the diazo resin of the present invention.
5 to 30 parts by weight of diazo resin per 100 parts by weight, preferably
It is prepared by blending in an amount of 6 to 15 parts by weight. When the diazo resin content is less than 5 parts by weight, the image forming property of the obtained photosensitive plate and the durability of the printing plate are deteriorated. When the content of the diazo resin exceeds 30 parts by weight, the sensitivity of the photosensitive composition and the developability of the photosensitive plate are deteriorated.

When a compound having at least one photopolymerizable functional group in the molecule is further added to form a photosensitive composition, 2 to 20 parts by weight of the diazo resin is added to 100 parts by weight of the binder resin. Parts, preferably 3 to 10 parts by weight, a compound having a photopolymerizable functional group 0 to 40 parts by weight, preferably 5
It is prepared by blending each in an amount of ˜30 parts by weight.

When the amount of the compound having a photopolymerizable functional group is more than 40 parts by weight, the surface of the printing plate obtained by applying the photosensitive composition becomes sticky or exposed to light. It is not preferable because the durability may be reduced. The diazo resin according to the present invention can be used in combination with a conventional diazo resin obtained by using a conventional inorganic or organic coupling agent. The usage ratio can be used with this diazo resin / conventional diazo resin = 100/0 to 10/90.

The photosensitive resin composition of the present invention further contains other image colorants such as dyes and pigments. The image colorant is blended for the plate inspection property and the easy handling of the printing plate, and a basic dye and an oil-soluble dye are preferable. Specifically, Victoria Pure Blue BOH, Victoria
Blue BH, methyl violet, Eisen macalite green (above, Hodogaya Chemical Co., Ltd.), patent
Basic dyes such as Pure Blue VX, Rhodamine B, Methylene Blue (above, manufactured by Sumitomo Chemical Co., Ltd.), Sudan Blue II, Victoria Blue F4R (above,
BASF), oil blue # 603, oil blue BOS, oil blue IIN (above, manufactured by Orient Chemical Industry).

These coloring materials are based on the binder resin 100.
It is contained in the photosensitive composition of the present invention in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 4 parts by weight, based on parts by weight. If the content of the coloring material is less than 0.1 part by weight, the visibility of the image area cannot be obtained. When the content of the coloring material is more than 5 parts by weight, the sensitivity of the photosensitive composition is lowered, so that the image forming property of the obtained photosensitive plate is lowered.

The photosensitive composition of the present invention contains a solvent, a filler, a pigment, a photodegradable acid generator, a surfactant for improving the coating property, an antifoaming agent, and other organic and inorganic fillers. Additives may also be included. As an organic filler,
A microgel (particle size 0.01 to 5 μm) having a gel inside is preferable. An example thereof is shown in Japanese Patent Application No. 3-36029.

A lithographic printing plate is prepared by a conventional method using the photosensitive resin composition of the present invention. For example, first, the photosensitive resin composition of the present invention is applied to a suitable support. Examples of the support include paper; plastic
Paper laminated with (for example, polyethylene, polypropylene, polystyrene, etc.); metal plates such as aluminum (including aluminum alloy), zinc, copper; cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate, acetic acid Examples thereof include films of plastics such as methyl cellulose, ethyl cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal; and papers or plastic films laminated or vapor-deposited with the above metals. Of these supports, the aluminum plate is particularly preferable because it is excellent in dimensional stability, relatively lightweight and inexpensive. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-B-48-18327 is also preferable.

Further, in the case of a support having a surface of metal, especially aluminum, it is desirable to carry out hydrophilic treatment by a known method.

The coating method is not particularly limited, for example, using a bar coater or the like, and then 1 to 40 ° C.
Dry for 10 minutes. The coating amount after drying is about 0.5 to 2.5 g / m ² . If necessary, a resin soluble in an alkaline developer,
For example, an overcoat layer may be provided by further coating polyvinyl alcohol, hydroxypropyl methylcellulose, etc. and drying.

Then, a negative or positive film is covered on the obtained dried coating film, and exposure and development are carried out by a usual method to obtain a lithographic printing plate. Examples of the light source used for exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a metal halide lamp, a tungsten incandescent lamp, an ultraviolet ray, an ultraviolet ray and a visible light laser beam. In the conventional system, the light exposure is merely irradiation with light which accelerates the decomposition of the diazonium group by these light sources, but in the present invention, (1) exposure for decomposing the diazonium group, (2) decomposition of the initiator Two types of exposures can be selected. Therefore,
In the first exposure, the diazo resin is decomposed to perform photocrosslinking and development, and then in the second exposure, the initiator is decomposed to crosslink, and further, in the first exposure, the initiator is added. An exposure method or the like in which the diazo resin is decomposed and photopolymerized and then the diazo resin is decomposed and crosslinked by the second exposure becomes possible, and can be appropriately selected depending on the purpose.

Development is preferably carried out with an alkali developing solution. Examples of the alkali agent mixed in the alkaline developer include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, and ammonium triphosphate. Inorganic dibasic ammonium phosphates, sodium metasilicate, sodium bicarbonate, ammonia, etc., and monomethylamine, dimethylamine,
Trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, n-butylamines, monoethanolamine, diethanolamine, triethanolamine,
Monoisopropanolamine, di-isopropanolamine, triisopropanolamine, ethyleneimine,
Organic amine compounds such as ethylenediamine, pyridine and the like can be mentioned. Examples of the solvent for the alkaline agent include water (particularly deionized water). Further, benzyl alcohol, phenyl cellosolve, ethyl cellosolve and the like are used as necessary. Further, the concentration of the alkaline agent and the like are appropriately selected.

[0078]

The diazo resin of the present invention has a remarkably high crosslinkability with the binder resin to be blended and is highly sensitive. Although not intended to be limited to a particular mechanism and theory,
It can be considered as follows. There are two types of compositions: (1) not containing a photopolymerizable compound and (2) containing a photopolymerizable compound.

In the case of (1), the i diazo resin is decomposed by irradiation with active energy rays to crosslink the binder resin. ii Sensitizing action of the initiator (the initiator is excited, and the excitation energy thereof causes the diazo resin to be excited and decomposed).

In the case of (2), i The diazo resin decomposes to crosslink the binder resin. ii Sensitizing action of the initiator (the initiator is excited, and the excitation energy thereof causes the diazo resin to be excited and decomposed). iii The initiator decomposes to generate radicals and photopolymerize the monomers and the like. iv Sensitizing action of diazo resin (the diazo resin is excited, and its excitation energy excites and decomposes the initiator to photopolymerize a monomer and the like).

Particularly, in the present invention, since the diazonium group and the initiator are present at the same time in the diazo resin, it is possible to utilize the sensitizing action by exciting the diazo resin and / or the initiator up to triplet by light irradiation. It is conceivable that the sensitivity will be higher and the photosensitive wavelength will be wider than under the conventional system even under the same light irradiation conditions. This phenomenon can be seen even when compared with the case of simply blending the same concentration of an initiator and a conventional diazo resin, but the system of the present invention is more sensitive because the initiator is a diazonium group counter anion. It is considered that this is because the excitation energy is transferred very efficiently because it exists in the vicinity of.

[0082]

The photosensitive resin composition of the present invention has the following 4
Have one effect. (1) High sensitivity: High sensitivity to actinic energy rays and an image can be formed at least with an exposure amount. Alternatively, at least the amount of diazo resin used can form an image. (2) Stability of resin: It is stable under the conditions even when the diazo resin or the photosensitive composition is left at room temperature for a long time or at high humidity or high temperature, and does not cause deterioration reaction such as decomposition or crosslinking. . (3) Solubility in organic solvent: The solubility range of the solvent used when forming a film as a photosensitive composition is wide. In particular,
It can be made free of harmful solvents such as DMF and methicello. (4) Durability of plate material: It has high printing durability when the plate material obtained by using the diazo resin is used for printing. This has a high reactivity of the diazo resin itself used, and also has a high crosslinking density due to a crosslinking reaction with the binder resin.

[0083]

The present invention will be further described by the following examples, but the present invention is not limited thereto.

Examples 1-6 illustrate the preparation of the diazo resins of this invention.

[0085]

Example 1 4-diazo-diphenylamine hydrogensulfate 29.
3 parts (0.1 mol) was dissolved in 100 parts concentrated sulfuric acid under ice cooling. To this reaction liquid, 3 parts (0.1 mol) of paraformaldehyde was gradually added, and the reaction temperature was kept so as not to exceed 10 ° C. Two
After reacting for a period of time, the reaction mixture was poured into 1 liter of ethanol under ice cooling, and the precipitate formed was filtered off. After extensive washing with ethanol, the precipitate was dissolved in 200 ml deionized water. A precipitate was formed by adding an aqueous solution containing 13.6 parts of zinc chloride to the resulting aqueous solution. The precipitate formed was filtered off and washed with ethanol. The resin thus obtained was redissolved in 200 ml of deionized water, and 32.8 parts of anthraquinone 2-sodium sulfonate was added to the aqueous solution to carry out an anion exchange reaction. The obtained precipitate was separated by filtration, washed with deionized water, and then dried at room temperature for one day to obtain diazo resin 1. The molecular weight of this diazo resin was measured by GPC. As a result, the weight average molecular weight was 2,200. When the solubility of the diazo resin 1 in an organic solvent was evaluated, it was well dissolved in DMF, methyl cellosolve, and methoxypropanol.

[0086]

Example 2 4-diazo-4'-methoxydiphenylamine sulfate 32.5 instead of 4-diazo-diphenylamine sulfate
Part (0.1 mol), paraformaldehyde 2.7 parts (0.09
Mol) and using 29.8 parts of a sodium salt of 4-sulfomethylbenzophenone in place of sodium anthraquinone 2-sulfonate, as in Example 1,
Diazo resin 2 was obtained. The weight average molecular weight of the obtained diazo resin 2 was 2,300. When the solubility of the diazo resin 2 in an organic solvent was evaluated, it was well dissolved in DMF, methyl cellosolve and methoxypropanol.

[0087]

Example 3 4-Diazo-diphenylamine sulfate 29.2 parts
(0.08 moles), 4.4 parts (0.1 moles) of acetaldehyde in place of paraformaldehyde, and 31.1 parts of soda salt of 4-sulfomethylbenzyl in place of sodium anthraquinone 2-sulfonate. Diazo resin 3 was obtained in the same manner as in Example 1. The weight average molecular weight of the obtained diazo resin 3 was 3000. When the solubility of the diazo resin 3 in an organic solvent was evaluated, it was dissolved in DMF, methyl cellosolve and methoxypropanol.

[0088]

Example 4 4-diazodiphenylamine 16.6 parts (0.057 mol) and benzyltrimethylammonium chloride 8.1 parts (0.043) instead of 4-diazo-diphenylamine sulfate.
Mol) and 3.3 parts of sodium anthraquinone 2-sulfonate and sodium hexafluorophosphate 15.1
A diazo resin 4 was obtained in the same manner as in Example 1 except that an aqueous solution containing 1 part and 2 parts was used. Obtained diazo resin 4
Had a weight average molecular weight of 4,500. When the solubility of the diazo resin 4 in an organic solvent was evaluated, it was dissolved in DMF, methyl cellosolve, and methoxypropanol.

[0089]

Example 5 Anthraquinone 2-Sulfonate Sodium Salt 1 of 4-Sulfomethylbenzophenone 1 Instead of Sodium Sulfonate 1
A diazo resin 5 was obtained in the same manner as in Example 1 except that a mixture of 4.9 parts and 15 parts of a sodium salt of 3-sulfopropoxythioxanthone was used. The weight average molecular weight of the obtained diazo resin 5 was 2,200. When the solubility of the diazo resin 5 in an organic solvent was evaluated, it was well dissolved in DMF, methyl cellosolve, and methoxypropanol.

[0090]

Example 6 A diazo resin 6 was obtained in the same manner as in Example 2 except that 34 parts of soda salt of 2- (3-sulfopropoxy) thioxanthone was used in place of sodium anthraquinone 2-sulfonate. The weight average molecular weight of the obtained diazo resin 6 was 2,900. When the solubility of the diazo resin 6 in an organic solvent was evaluated, it was well dissolved in DMF, methyl cellosolve, and methoxypropanol.

[0091]

Comparative Example 1 In the same manner as in Example 1 except that an aqueous solution containing 16.8 parts of sodium hexafluorophosphate was used instead of anthraquinone 2-sulfonate sodium.
Diazo resin 7 was obtained. The weight average molecular weight of the obtained diazo resin 7 was 2,200. When the solubility of the diazo resin 7 in the organic solvent was evaluated, it showed good solubility only in DMF.

Examples 7 to 12 describe a photosensitive plate and a printing plate using the diazo resin of the present invention.

[0093]

Example 7 A photosensitive resin composition having the composition shown in Table 1 below was prepared using the diazo resin 1 prepared in Example 1.

[0094]

[Table 1] Composition (parts by weight) Alkali-soluble acrylic resin 1 ¹⁾ 9.0 Diazo resin 1 prepared in Example 1 1.9 Methoxypropanol 40.00 Dimethylformamide 49.75 Victoria Pure Blue 0.025 ¹⁾ 100 parts of 2-hydroxyethyl methacrylate, acrylonitrile 40 Acrylic resin with a molecular weight of 25,000 prepared using 10 parts, 50 parts isobutyl methacrylate and 10 parts methacrylic acid

When the obtained photosensitive resin composition solution was placed in a container and allowed to stand for 3 days, no precipitates or separated substances were observed and it had good stability. Further, the photosensitive resin composition solution is applied to a roughened and hydrophilized aluminum plate with a bar coater and dried at 80 ° C. for 4 minutes to provide a negative type photosensitive plate for offset printing with a coating weight of 2 g / m ^2. Got The composition had good coatability and could be applied uniformly, and no coating abnormalities such as spots and cissing were observed.

Then, a printing plate was prepared using the obtained photosensitive plate and the image forming property was evaluated. First, the photosensitive plate was image-exposed for 1 minute and 30 seconds through a negative from a distance of 1.2 m with a vacuum printer HVP-22H manufactured by Sakaguchi Seiwa Kogyo Co., Ltd. (an idle fin metal halide lamp with a power of 3 KW manufactured by Eye Graphics Co., Ltd.), A lithographic printing plate was obtained by developing with an automatic processor at a developing speed of 80 cm / min using a water dilution of a negative developer of 1: 1 and gumming with a gum solution. The obtained printing plate has no development residue, the number of steps is 2 to 15, the dot residual property is 0.05 to 97%, and the fine line residual size is 4.
It had a good image reproducibility of μ and a reverse line of 20μ.

Then, the durability and printability of the obtained printing plate were evaluated. First, a rubbing test was performed 100 times on the surface of the printing plate taken out from the automatic developing machine using absorbent cotton soaked with water. As a result, it was shown that the printing plate had sufficient durability of the image area without rubbing of the image area or exposure of the support member due to abrasion even after rubbing.

On the other hand, another obtained printing plate was attached to a small lithographic printing machine Hamada Star 700CDX manufactured by Hamada Printing Machinery Co., Ltd., and printed on high quality paper using a commercially available ink. As a result, 100,000 sheets could be printed satisfactorily without staining the non-image area.

[0099]

Comparative Example 2 A photosensitive plate was obtained in the same manner as in Example 7 except that 1.0 part of diazo resin 7 was used instead of diazo resin 1. The obtained photosensitive plate was evaluated for image forming property in the same manner as in Example 7. The printing plate obtained had no development residue, the number of steps was 2 to 12, and the halftone dot residual property was 0.05 to 98.
%, The remaining size of the fine line was 4 μ, and the reverse line was 15 μ.

[0100]

Comparative Example 3 A photosensitive plate was obtained in the same manner as in Example 7, except that 1.0 part of diazo resin 7 and 0.9 part of anthraquinone 2-sulfonic acid sodium were used in place of diazo resin 1. The image forming property of the obtained photosensitive plate was evaluated in the same manner as in Example 7. The obtained printing plate had no development residue, the number of steps was 2 to 13, and the halftone dot residual property was 0.05 to 98%.
The fine line remaining size was 4μ and the reverse line was 15μ.

[0101]

Example 8 An acid value of 54.6 having the composition shown in Table 2 below,
Using the alkali-soluble acrylic resin 2 having a hydroxyl value of 199 and a molecular weight of 22,000 and the diazo resin 2 obtained in Example 2,
A photosensitive composition having the composition shown in Table 3 was prepared.

[0102]

[Table 2] Ingredients Composition (parts by weight) 2-Hydroxypropyl methacrylate 46 Acrylonitrile 15 Isobutyl methacrylate 28.9 SPE ¹⁾ 2.5 Methacrylic acid 7.6 ¹⁾ N, N-Dimethyl-N-methacrylamidopropyl-N- (3-sulfopropyl) Ammonium betaine, Mn = 292

[0103]

[Table 3] Composition (parts by weight) Alkali-soluble acrylic resin 2 8.7 Microgel ¹⁾ 0.46 Diazo resin 2 1.2 Victoria pure blue / BOH 0.05 methoxypropanol 69.75 Isopropanol 20 ¹⁾ Polymer emulsifier / ethylene glycol dimethacrylate /
Methylene methacrylate / n-butyl acrylate, 10 /
0.24μm particle size microgel obtained by emulsion polymerization at a ratio of 30/10/45

A photosensitive plate was obtained in the same manner as in Example 7 except that the obtained resin was used instead of the diazo resin 2.
When the photosensitive plate was tested for durability and printability in the same manner as in Example 7, the printing plate obtained exhibited the same performance as the printing plate of Example 7.

[0105]

Examples 9 to 12 Diazo resins 3, 4, 5 and 6 were used in place of the diazo resin 2, and durability and printability tests were conducted in the same manner as in Example 8 to obtain printing plates. Showed the same performance as Example 8.

[0106]

Example 13 Using the diazo resin 1 prepared in Example 1, a photosensitive resin composition having the composition shown in Table 2 below was prepared.

[0107]

[Table 4] Composition (parts by weight) Alkali-soluble acrylic resin 1 7.0 Diazo resin 1 1.0 Triethylene glycol dimethacrylate 1.0 Trimethylolpropane triacrylate 1.0 Methoxypropanol 40.0 Dimethylformaside 45.0 Victoria Pure Blue 0.025 Obtained photosensitive resin composition The product was applied in the same manner as in Example 1 to obtain a negative type photosensitive plate for offset printing.

First, the photosensitive plate is a vacuum printer HVP-22H manufactured by Sakaguchi Seiwa Kogyo Co., Ltd. (Idle Fins Metal Halide Lamp of 3KW electric power manufactured by Eye Graphics Co., Ltd.).
After image exposure for 1 minute and 30 seconds through a negative from a distance of 2 m, it was developed with an automatic processor at a developing speed of 80 cm / min using a water diluting solution having a weight ratio of 1: 1 of a negative developing solution. Next, a lithographic printing plate was obtained by post-exposure with a medium-pressure mercury lamp from a distance of 1.2 m for 5 minutes and then gumming. The obtained printing plate has good image reproducibility without any development residue,
Even in the print test, it was possible to print 150,000 sheets and had sufficient printing durability.

Claims (6)

[Claims] 1. A photosensitive resin composition for lithographic printing comprising a photosensitive diazo resin, which contains a photopolymerization initiator having at least one anion group in the molecule as a counter anion of a diazonium group. 2. The photosensitive resin composition for lithographic printing according to claim 1, wherein the photopolymerization initiator is selected from the group consisting of benzophenones, benzyls, thioxanthones, benzoins, and anthraquinones. object. 3. The photosensitive resin composition for lithographic printing according to claim 1, further comprising a binder resin. 4. The photosensitive resin composition for lithographic printing according to claim 3, further containing a compound having at least one photopolymerizable functional group in the molecule. 5. A method for obtaining a molded product by simultaneously irradiating the composition of claim 1 with active energy rays having a wavelength that excites a diazonium group and a wavelength that excites an initiator. 6. A method for obtaining a molded product by separately irradiating the composition of claim 1 with active energy rays having a wavelength that excites a diazonium group and an wavelength that excites an initiator.