JP2006053316A - Platemaking method of planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a platemaking method of a planographic printing plate excellent in processability and particularly suitable for drawing with laser light. <P>SOLUTION: The platemaking method of a planographic printing plate includes a development step of imagewise exposing a planographic printing original plate having a polymerizable photosensitive layer and a protective layer layered in this order on a supporting body and developing the image with an alkali aqueous solution, wherein the protective layer contains polyvinylalcohol having an acid group or an acid group salt in the molecule, and the protective layer is removed by dissolving in the alkali aqueous solution during the developing step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plate making method for a lithographic printing plate, and more particularly to a plate making method for a lithographic printing plate which is excellent in processability and particularly suitable for drawing with a laser beam.

Conventionally, a lithographic printing plate has a structure in which a photosensitive resin layer is provided on a support having a hydrophilic surface. As a plate-making method, usually, surface exposure (mask exposure) is performed through a lithographic film. The desired printing plate was obtained by removing the non-image area with a developer. However, computer-to-plate that directly exposes the plate without using a lith film by scanning the plate with highly directional light such as laser light according to the digitized image information using recent digitization technology. (CTP) technology has been developed and photosensitive lithographic printing plates adapted to this have been developed.
Examples of the photosensitive lithographic printing plate suitable for exposure with such laser light include a photosensitive lithographic printing plate using a polymerizable photosensitive layer. This is because the polymerizable photosensitive layer can be easily increased in sensitivity as compared with other conventional photosensitive layers by selecting a photopolymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system).

  These polymerizable photosensitive layers have been confirmed to be free from radical reaction due to the influence of oxygen in the atmosphere, and lithographic printing plates having such a photosensitive layer are oxygenated for the purpose of blocking oxygen in the atmosphere. It was necessary to coat a protective layer with extremely low permeability on the surface of the photosensitive layer.

Patent Document 1 (Japanese Patent Laid-Open No. 2003-98674) discloses a photosensitive layer containing a photopolymerization initiator, a compound having an ethylenically unsaturated double bond, and a polymer binder on a support, and oxygen permeability. Has disclosed a photopolymerizable lithographic printing plate having a protective layer of 1 × 10 ⁻¹⁵ [cm ³ (STP) · cm / cm ² · sec · cmHg] or more in succession. A protective layer mainly composed of polyvinyl alcohol having a very high degree was used.

  Such polyvinyl alcohol having a high degree of saponification has excellent oxygen blocking ability, but once dissolved in an alkaline developer, it re-deposits with time, and the gel-like precipitate enters the developing tank. It has been confirmed that this causes accumulation of the printing solution, shortening the working days of the developing solution, increasing the frequency of replacing the solution, and depositing the precipitate on the plate during development. Therefore, generally, a method of removing this protective layer in advance by washing with water or the like before the development processing is employed. In this case, an automatic developing machine of a type in which a washing tank is provided in front of the developing tank is employed. However, in consideration of space and price, it is preferable to use a system corresponding to an automatic processor without a washing tank.

JP 2003-98674 A

  An object of the present invention is to provide a lithographic printing plate making method which is excellent in processability and particularly suitable for drawing with a laser beam.

As a result of intensive studies, the present inventors have succeeded in achieving the object with the following configuration.
That is, the present invention is as follows.
(1) A lithographic printing plate making method comprising a development processing step in which a lithographic printing plate precursor having a polymerizable photosensitive layer and a protective layer laminated in this order on a support is imagewise exposed and developed with an aqueous alkali solution. The lithographic printing plate is characterized in that the protective layer contains polyvinyl alcohol having an acid group or an acid group salt in the molecule, and the protective layer is eluted and removed in an alkaline aqueous solution during the development processing step. How to make a printing plate.
(2) The plate making method of a lithographic printing plate as described in (1) above, wherein the acid group constituting the acid group or the salt of the acid group is a carboxylic acid or a sulfonic acid.
(3) The plate making method of a lithographic printing plate as described in (1) or (2) above, wherein the imagewise exposure is exposure with a laser having an emission wavelength in the range of 300 nm to 1100 nm.

The following configuration is also preferable.
The plate making method of a lithographic printing plate as described in (1) above, wherein the protective layer is eluted and removed in an aqueous alkaline solution during the development step without being washed with water before the development treatment.

  According to the present invention, a plate making method of a lithographic printing plate that is stable and can be processed for a long period of time even in an automatic developing machine without a washing tank and is particularly suitable for drawing with a laser beam is provided.

(Protective layer)
In the present invention, an oxygen-blocking protective layer (overcoat layer) is provided to prevent the action of inhibiting the polymerization of oxygen.
The coating weight of the protective layer in the present invention is preferably in the range of 0.7~3.0g / m ^2. By setting the coating mass to 0.7 g / m ² or more, the sensitivity can be further improved, and by setting the coating mass to 3.0 g / m ² or less, the burden on the processing process can be further reduced.

In the present invention, polyvinyl alcohol having an acid group or an acid group salt in the molecule (hereinafter sometimes referred to as modified polyvinyl alcohol) is used as the oxygen-blocking protective layer.
The acid group means an anionic group capable of releasing a proton. Examples of the acid constituting the acid group include carboxylic acid, sulfonic acid and phosphoric acid. Of these, carboxylic acid or sulfonic acid groups are preferred. The acid group may constitute a salt together with a cation. As the cation, a metal ion is preferable, and an alkali metal ion such as sodium ion is particularly preferable. The modified polyvinyl alcohol is more stable as a molecular structure when the acid group is in a salt state than in a free state. In the production of polyvinyl alcohol used in the present invention, an acid residue or a salt of an acid residue as described above is introduced into the polyvinyl alcohol molecule. Therefore, this polyvinyl alcohol is a kind of modified polyvinyl alcohol (modified poval). The modified poval is described in “Poval (revised version)” (Polymer Publishing Association), pages 280-285. Ordinary polyvinyl alcohol is generally produced by saponifying polyvinyl acetate. The introduction of acid groups can be carried out in two ways: (1) copolymerization modification in the production of polyvinyl acetate and (2) post-modification after production of ordinary polyvinyl alcohol.

  In the copolymerization modification (1), vinyl acetate and an organic acid (or a derivative thereof) having an ethylenically unsaturated group are copolymerized. Examples of the ethylenically unsaturated organic acid include acrylic acid, methacrylic acid, and styrene sulfonic acid. An organic acid derivative means any state of a salt, an ester, an amide, or an acid anhydride. For example, ethylenically unsaturated organic acid amides such as acrylamide, methacrylamide and N, N-dimethylacrylamide can also be used. Polyvinyl alcohol having an acid group is produced by saponifying a copolymer of vinyl acetate and an organic acid having an ethylenically unsaturated group in the same manner as ordinary polyvinyl alcohol. When the organic acid is in the form of an ester, amide or acid anhydride, hydrolysis occurs in this saponification treatment, and an acid group is generated from the bond of the ester, amide or acid anhydride.

  (2) In post-modification, a bifunctional or higher acid (dibasic acid, tribasic acid, tetrabasic acid) is reacted with a hydroxyl group of polyvinyl alcohol. Thereby, one of a plurality of functional groups of the acid is ester-bonded with the hydroxyl group, and the remaining acid functional groups are released. The acid is preferably a bifunctional or higher carboxylic acid (dicarboxylic acid, tricarboxylic acid, tetracarboxylic acid). Bi- or higher functional carboxylic acids can be used in the anhydride state. For example, maleic anhydride, phthalic anhydride, trimellitic anhydride, succinic anhydride, adipic anhydride and itaconic anhydride can be used.

The modified polyvinyl alcohol is effective in the present invention regardless of whether it is produced by either method (1) or (2). However, the post-modification of (2) is easier to produce or obtain a commercial product.
The molecular weight of the modified polyvinyl alcohol is preferably in the range of 3000 to 500,000. Vinyl acetate units may remain in the modified polyvinyl alcohol. That is, the saponification degree does not need to be 100%. Moreover, it is difficult to produce polyvinyl alcohol having a saponification degree of 100%. However, the saponification degree is preferably 70% or more, and more preferably 90% or more. As described above, the modified polyvinyl alcohol used in the present invention is generally a copolymer composed of three types of units: (A) vinyl acetate unit, (B) vinyl alcohol unit, and (C) acid group unit. The arrangement of each unit in the copolymer may be a graft, but is preferably random. A preferable example of each unit is represented by the following formula.

The above formula (A) means a unit of vinyl acetate. l is preferably 30% or less, more preferably 10% or less, of the total (degree of polymerization) of l + m + n1 (or n2). The vinyl acetate unit in (A) is not present (even if l is 0),
The effect of the present invention can be obtained. Formula (B) means a unit of vinyl alcohol. Formula (C1) is a unit of an acid group introduced by copolymerization modification of (1). In the formula (C1), R is a hydrogen atom, an alkyl group, a carboxylic acid group or a salt thereof. R ′ is a hydrogen atom, a carboxylic acid group or a salt thereof. The alkyl group is preferably a lower alkyl group having 6 or less carbon atoms, and particularly preferably methyl. Link ¹ is a q + 1 valent linking group. The linking group is preferably a hydrocarbon residue. p is 0 or 1; p = 0, that is, there may be no linking group. q is a natural number and is generally 1 or 2. Acid ¹ is an acid group (eg, carboxylic acid group, sulfonic acid group, phosphoric acid group). M ¹ is a cation. The cation is preferably a proton or an alkali metal ion. n1 is preferably in the range of 0.1 to 20%, more preferably in the range of 0.5 to 10%, with respect to the sum (polymerization degree) of l + m + n1. Specific examples of the modified polyvinyl alcohol produced by copolymerization modification in (1) are listed below with reference to the above formulas (A), (B) and (C1).

Formula (C2) is a unit of an acid group introduced by post-modification of (2) above. In Formula (C2), Link ² is an s + 1 valent linking group. The linking group is preferably a hydrocarbon residue. r is 0 or 1; r = 0, that is, there may be no linking group. s is a natural number and is generally 1 or 2. Acid ² is an acid group (eg, carboxylic acid group, sulfonic acid group, phosphoric acid group). M ² is a cation. The cation is preferably a proton or an alkali metal ion. n2 is preferably in the range of 0.1 to 20%, more preferably in the range of 0.5 to 10%, with respect to the sum (polymerization degree) of l + m + n2. Specific examples of the modified polyvinyl alcohol produced by (2) post-modification are listed below with reference to the above formulas (A), (B) and (C2).

A commercially available product may be used as the modified polyvinyl alcohol of the present invention. Examples of commercially available products include Kuraray Poval KM-118, KL-118, KL-318, KL-506, KM-106, KM-118, KM-618, SK-5102 (manufactured by Kuraray Co., Ltd.), Gohsenal T , And Gooselan L-3266 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). Two or more kinds of modified polyvinyl alcohol may be used in combination. The amount of the modified polyvinyl alcohol used in the protective layer is preferably in the range of 0.5 g / m ² to 3.0 g / m ² , more preferably 0.7 g / m ² to 2.9 g / m ² . The range is more preferably 1.0 g / m ² to 2.5 g / m ² .

In the present invention, pure water is preferable as a solvent used for applying the oxygen-blocking protective layer, but alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone may be mixed with pure water. The concentration of the solid content in the coating solution is preferably 1 to 20% by mass. In the oxygen-blocking protective layer of the present invention, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film may be added. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. Further, a water-soluble (meth) acrylic polymer or the like may be added. The coating amount is preferably in the range of 0.01 g / m ² to about 2 g / m ² in terms of mass after drying. More preferably from ^{0.1g / m 2 ~1.0g / m 2} .

[Lithographic printing plate precursor]
Next, the structure of the negative lithographic printing plate precursor having spectral sensitivity in the wavelength range of 300 nm to 1100 nm, for example, used in the present invention will be described sequentially.

[Support]
First, the support for the negative lithographic printing plate precursor used in the present invention will be described.
As the support that can be used in the present invention, any material can be used as long as the surface is hydrophilic, but a dimensionally stable plate-like material is preferable, for example, paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc. ) And laminated metal, and also metals such as aluminum (including aluminum alloys), zinc, copper etc. or alloys thereof (eg silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel and Alloy) plates, and plastics such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose butyrate acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. the film The above-described metal or alloys having laminated or vapor-deposited paper or plastic films. Of these supports, the aluminum plate is particularly preferred because it is dimensionally remarkably stable and inexpensive. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable. Usually, the thickness is about 0.05 mm to 1 mm.

In the case of a support having a surface of metal, particularly aluminum, surface treatment such as graining treatment described later, immersion treatment in an aqueous solution of sodium silicate, potassium fluoride zirconate, phosphate, or anodization treatment may be performed. It is preferable that it is made.
[Graining process]
Examples of the graining method include mechanical graining, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, electrochemical graining method that electrochemically grains in hydrochloric acid or nitric acid electrolyte solution, and wire brush grain method that scratches aluminum surface with metal wire, and ball grain method that graines aluminum surface with polishing ball and abrasive. Further, a mechanical graining method such as a brush grain method in which the surface is grained with a nylon brush and an abrasive can be used, and the above graining methods can be used alone or in combination.
Among them, the method of making the surface roughness usefully used in the present invention is an electrochemical method in which the surface roughness is chemically ground in hydrochloric acid or nitric acid electrolyte, and a suitable current density is 100 C / dm ^{2 to} 400 C. / Dm ² range. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 100 ° C., for 1 second to 30 minutes, electrolysis at a current density of 100C / dm ² ~400C / dm ² It is preferable to carry out.

The grained aluminum support is chemically etched with acid or alkali. When an acid is used as an etching agent, it takes time to destroy the fine structure, which is disadvantageous when the present invention is applied industrially, but it can be improved by using an alkali as the etching agent.
Examples of the alkali agent suitably used in the present invention include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like. The conditions are 50 mass%, 20 to 100 ° C., and the amount of dissolution of aluminum is 5 to 20 g / m ³ .
After etching, pickling is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And an alkali etching method described in Japanese Patent Publication No. 48-28123.
In addition, the surface roughness (Ra) of the aluminum support preferable in the present invention is 0.3 to 0.7 μm.

[Anodic oxidation treatment]
The aluminum support treated as described above is further anodized.
The anodizing treatment can be performed by a method conventionally performed in this technical field.
Specifically, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzene sulfonic acid, etc., or a combination of two or more of these, and when direct current or alternating current is applied to aluminum in an aqueous solution or non-aqueous solution, aluminum is supported. An anodized film can be formed on the body surface.

The conditions of the anodizing treatment cannot be determined unconditionally because they vary depending on the electrolytic solution used. In general, the concentration of the electrolytic solution is 1 to 80%, the liquid temperature is 5 to 70 ° C., the current density is 0.00. A range of 5 to 60 amperes / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 to 100 seconds is appropriate.
Among these anodizing treatments, in particular, the method of anodizing at high current density in sulfuric acid described in British Patent 1,412,768, and US Pat. No. 3,511,661. A method of anodizing phosphoric acid described in the book as an electrolytic bath is preferred.
In the present invention, the anodized film is preferably 1 to 10 g / m ² . More preferably, it is 1.5-7 g / m < ² >, More preferably, it is 2-5 g / m < ² >.

  Furthermore, in the present invention, the support may be subjected to a sealing treatment after graining treatment and anodizing. Such sealing treatment is performed by immersing the substrate in a hot aqueous solution containing hot water and an inorganic salt or an organic salt, a steam bath, or the like. Further, the support used in the present invention is subjected to a surface treatment such as a silicate treatment with an alkali metal silicate or other treatment, for example, an immersion treatment in an aqueous solution of potassium fluorinated zirconate or phosphate. Also good.

  In the present invention, a polymerizable photosensitive layer made of, for example, a polymerizable photosensitive composition is coated on a support (in the case of aluminum, aluminum that has been appropriately surface-treated as described above), and then, By applying the protective layer, a negative lithographic printing plate precursor is formed. However, before coating the polymerizable photosensitive layer, an organic or inorganic subbing layer may be provided as necessary. A sol-gel treatment in which a functional group capable of causing an addition reaction by a radical as disclosed in Kaihei 7-159983 is covalently bonded may be applied.

Substances forming the organic undercoat layer include water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having sulfonic acid groups in the side chain, polyacrylic acid, water-soluble metal salts (for example, zinc borate) or , Yellow dyes, amine salts and the like.
More specifically, examples of the organic compound used in the organic undercoat layer may include phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and a substituent. Organic phosphonic acids such as phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphonic acid, naphthylphosphonic acid, alkylphosphoric acid and Organic phosphoric acids such as glycerophosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanol Hydroxy such as amine hydrochloride -Alanine, and hydrochlorides of amines having a group may be used as a mixture of two or more.

  This organic undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like, or a mixed solvent thereof is dissolved on the support, and a method of providing the substrate by drying, water, methanol, ethanol, methyl ethyl ketone, etc. The organic compound is dissolved in a solution of the above organic compound or a mixed solvent thereof to immerse the support so that the organic compound is adsorbed, and then washed with water and dried to provide an organic undercoat layer. Is the method. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time. Is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute.

The solution used for this can be used in a pH range of 1 to 12 by adjusting the pH with a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. In addition, a yellow dye can be added to improve tone reproducibility of the negative lithographic printing plate precursor.
The coating amount after drying of the organic undercoat layer is preferably ² to 200 mg / m ² , more preferably 5 to 100 mg / m ² . Sufficient printing durability can be obtained within the above range.

  In addition, examples of the material used for the inorganic undercoat layer include inorganic salts such as cobalt acetate, nickel acetate, and potassium fluorotitanate. The method of providing this inorganic undercoat layer is the same as the organic undercoat layer described above. is there.

(Polymerizable photosensitive layer)
The polymerizable photosensitive layer of the lithographic printing plate precursor used in the present invention has spectral sensitivity in a wavelength range of at least 300 nm to 1100 nm. In consideration of a laser light source currently used as a general purpose, a more preferable spectral sensitivity region is either a wavelength range of 300 nm to 550 nm or a wavelength range of 760 nm to 1100 nm. More preferably, it is a negative lithographic printing plate precursor comprising the following (i) to (iii).
(I) a sensitizing dye having an absorption maximum in a wavelength range of 300 nm to 550 nm or a wavelength range of 760 nm to 1100 nm,
(Ii) A photopolymerization initiator, preferably a titanocene compound, and (iii) an addition polymerizable compound having an ethylenically unsaturated double bond.

[Sensitizing dye]
First, the sensitizing dye having an absorption maximum in the wavelength region of 300 nm to 550 nm used in the negative lithographic printing plate precursor used in the present invention will be described. Examples of such a sensitizing dye include merocyanine dyes represented by the following general formula (2), benzopyrans and coumarins represented by the following general formula (3), and fragrances represented by the following general formula (4). Group ketones, anthracenes represented by the following general formula (5), and the like.

(In the formula, A represents an S atom or NR ₆ , R ₆ represents a monovalent non-metallic atomic group, Y represents a basic nucleus of the dye in cooperation with the adjacent A and the adjacent carbon atom. A non-metallic atomic group, X ₁ and X ₂ each independently represent a monovalent non-metallic atomic group, and X ₁ and X ₂ may combine with each other to form an acidic nucleus of the dye.)

(In the formula, = Z represents a carbonyl group, a thiocarbonyl group, an imino group or an alkylidene group represented by the partial structural formula (1 ′), and X ₁ and X ₂ have the same meanings as in the general formula (2). R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.)

(In the formula, Ar ₃ represents an aromatic group or a heteroaromatic group which may have a substituent, and R ₁₃ represents a monovalent nonmetallic atomic group. More preferred R ₁₃ represents an aromatic group or It is a heteroaromatic group, and Ar ₃ and R ₁₃ may be bonded to each other to form a ring.)

(In the formula, X ₃ , X ₄ and R _{14 to} R ₂₁ each independently represent a monovalent non-metallic atomic group, and more preferable X ₃ and X ₄ are electron donating groups having a negative Hammett's substituent constant. .)

In the general formulas (2) to (5), preferred examples of the monovalent nonmetallic atomic group represented by X ₁ to X ₄ and R ₆ to R ₂₁ include a hydrogen atom, an alkyl group (for example, a methyl group, Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group , S-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group, chloromethyl group , Bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, methoxyethoxy Ethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl Group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, allyloxycarbonylbutyl group, chloro Phenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl Ru-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoyl group Propyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphine group Onatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, syn Namyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc.), aryl group (for example , Phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, Acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, Noxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), heteroaryl group (for example, thiophene, thiathrene) , Furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, indazole, purine, quinolidine, isoquinoline, phthalazine , Naphthyridine, quinazoline, cynoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenazazine, fu Noxazine, furazane, phenoxazine, etc.), alkenyl groups (eg, vinyl, 1-propenyl, 1-butenyl, cinnamyl, 2-chloro-1-ethenyl, etc.), alkynyl (eg, ethynyl, 1 -Propynyl group, 1-butynyl group, trimethylsilylethynyl group, etc.), halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyl Dithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group , Carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoy Ruoxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N- Alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N′-diarylureido group, N '-Alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N', N ' -Dialkyl-N-alkylureido groups, N ', N'-dialkyl-N-arylureido groups N′-aryl-N-alkylureido group, N′-aryl-N-arylureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxy Carbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl Group, aryloxycarbonyl group, carbamoyl group, N-alkyl group Vamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group , Sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfina Moyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfur group Famoyl group, N-aryl Sulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonate group), dialkylphosphine Phono group (—PO ₃ (alkyl) ₂ ), diaryl phosphono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) (aryl)), monoalkyl phosphono group (— PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkyl phosphonate group), monoaryl phosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as aryl phosphonate group) ), Phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonateoxy group), dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), dia Reel phosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylaryl phosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (—OPO ₃ H (alkyl)) and its A conjugated base group (hereinafter referred to as an alkylphosphonatooxy group), a monoarylphosphonooxy group (—OPO ₃ H (aryl)) and a conjugated base group (hereinafter referred to as an arylphosphonatooxy group), a cyano group, A nitro group, and the like. Among these substituents, a hydrogen atom, an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acyl group are particularly preferable.

  In the general formula (2), the basic nucleus of the dye formed together with A adjacent to Y and the adjacent carbon atom includes a 5, 6 or 7-membered nitrogen-containing or sulfur-containing heterocyclic ring. A 5- or 6-membered heterocyclic ring is preferable.

  Examples of nitrogen-containing heterocycles include, for example, the basic nucleus in merocyanine dyes described in LGBrooker et al., J. Am. Chem. Soc., 73, 5326-5358 (1951). Any of those known to be used can be suitably used. Specific examples include thiazoles (for example, thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4,5- Di (p-methoxyphenylthiazole), 4- (2-thienyl) thiazole, etc.), benzothiazoles (for example, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7- Chlorobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzo Cheer , 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-di Oxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 6-dimethylaminobenzothiazole, 5-ethoxycarbonylbenzothiazole, etc.), naphthothiazoles (for example, naphtho [1,2] thiazole, naphtho [2 , 1] thiazole, 5-methoxynaphtho [2,1] thiazole, 5-ethoxynaphtho [2,1] thiazole, 8-methoxynaphtho [1,2] thiazole, 7-methoxynaphtho [1,2] thiazole, etc.) , Chianafuteno 7 ′, 6 ′, 4,5-thiazole (for example, 4′-methoxythianaphtheno-7 ′, 6 ′, 4,5-thiazole, etc.), oxazole (for example, 4-methyloxazole, 5-methyloxazole) 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, etc.), benzoxazoles (benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole) 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 6-methoxybenzoxazole, 5-methoxybenzoxazole, 4-ethoxybenzoxazole, 5-chloroben Zoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazoles (eg, naphtho [1,2] oxazole, naphtho [2,1] oxazole, etc.), selenazoles ( For example, 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazoles (for example, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzo Selenazole etc.), naphthoselenazoles (eg naphtho [1,2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), 2-quinolines (eg Quinoline, 3- Tilquinoline, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), 4 -Quinolines (eg, quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline, etc.), 1-isoquinolines (eg, isoquinoline, 3,4-dihydroisoquinoline, etc.), 3-isoquinolines (eg, , Isoquinoline, etc.), benzimidazoles (eg, 1,3-diethylbenzimidazole, 1-ethyl-3-phenylbenzimidazole, etc.), 3,3-dialkylindolenins (eg, 3,3-dimethylindolenin, 3,3,5-trimethylindolenine, 3,3 7, - trimethyl indolenine, etc.), 2-pyridines (e.g., pyridine, 5-methyl-pyridine, etc.), 4-pyridine (for example, a pyridine, etc.) or the like.

Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759.
Specific examples include benzodithiols (for example, benzodithiol, 5-t-butylbenzodithiol, 5-methylbenzodithiol, etc.), naphthodithiols (for example, naphtho [1,2] dithiol, naphtho [2,1] Dithiols, etc.), dithiols (for example, 4,5-dimethyldithiols, 4-phenyldithiols, 4-methoxycarbonyldithiols, 4,5-dimethoxycarbonylbenzodithiols, 4,5-ditrifluoromethyldithiols, 4 , 5-dicyanodithiol, 4-methoxycarbonylmethyldithiol, 4-carboxymethyldithiol and the like.

  As mentioned above, for the sake of convenience, the description used in the description of the heterocyclic ring has conventionally used the name of the heterocyclic mother skeleton, but when forming the basic skeleton partial structure of the sensitizing dye, for example, in the case of the benzothiazole skeleton It is introduced as an alkylidene-type substituent with one degree of unsaturation, such as a 3-substituted-2 (3H) -benzothiazolylidene group.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (1).

(In the general formula (1), A represents an aromatic ring or a hetero ring which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a hydrogen atom or a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be.)

The general formula (1) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or non-substituted It represents a substituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Preferable examples of R ₁ , R ₂ and R ₃ will be specifically described. Examples of preferable alkyl groups include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, s-butyl, Examples thereof include t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group and 2-norbornyl group. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

As the substituent of the substituted alkyl group, a monovalent nonmetallic atomic group excluding hydrogen is used, and preferred examples include a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, Aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, Reelsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N'-alkylureido group, N ', N'-dialkylureido group, N'-arylureido Group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N′- Alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N'- Aryl-N-arylureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-ary Luureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl- N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group , Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group , Alkylsul Finyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N -Alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group (-PO ₃ H ₂₎ and its conjugated base group (hereinafter, phospho Referred to as bets group), dialkyl phosphono group _{(-PO 3 (alkyl) 2)} , diaryl phosphono group _{(-PO 3 (aryl) 2)} , alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )) , Monoalkylphosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonate group), monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group (Hereinafter referred to as arylphosphonate group), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonateoxy group), dialkylphosphonooxy group (—OPO ₃ (alkyl)) ₂ ), diarylphosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylarylphosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkylphosphonooxy group (—OPO ₃ H (alkyl)) )and The conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (aryl)) and its conjugated base group (hereinafter referred to as aryl phosphite Hona preparative group), a cyano group , A nitro group, an aryl group, a heteroaryl group, an alkenyl group, and an alkynyl group.

  Specific examples of the alkyl group in these substituents include the above-described alkyl groups, and specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, a mesityl group, and a cumenyl group. , Chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylamino Phenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group Cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl phenyl group, phosphonophenyl phenyl group and the like.

As the preferred heteroaryl group as R ₁ , R ₂ and R ₃ , a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used. Examples of particularly preferred heteroaryl groups Is, for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indolizine, indazole, indazole, Purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenalazine, phenoxazine, flaza And phenoxazine and the like. These may be further benzo-fused and may have a substituent.

Examples of preferable alkenyl groups as R ₁ , R ₂ and R ₃ include vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group and the like, and alkynyl Examples of the group include ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group and the like. Examples of G ₁ in the acyl group (G ₁ CO—) include hydrogen and the above alkyl groups and aryl groups. Among these substituents, even more preferred are halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N— Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group Group, N-arylsulfa Yl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonate group, dialkyl phosphono group, diaryl phosphono group, monoalkyl phosphono group, alkyl phosphonate group, monoaryl phosphono group, aryl phosphine group Examples include an onato group, a phosphonooxy group, a phosphonateoxy group, an aryl group, and an alkenyl group.

  On the other hand, examples of the alkylene group in the substituted alkyl group include divalent organic residues obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Can include linear alkylene groups having 1 to 12 carbon atoms, branched chains having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferable substituted alkyl groups as R ₁ , R ₂ and R ₃ obtained by combining the substituent and the alkylene group include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxy Methyl group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N -Cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbo Nylethyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl- N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobu Group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonateoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p -Methylbenzyl group, cinnamyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc. Can be mentioned.

Specific examples of preferred aryl groups as R ₁ , R ₂ and R ₃ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group and a naphthyl group are more preferable. .

Specific examples of preferred substituted aryl groups as R ₁ , R ₂ and R ₃ include those having a monovalent non-metallic atomic group excluding hydrogen as a substituent on the ring-forming carbon atom of the aryl group described above. . Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenyl group, N-methylbenzoylaminophenyl group, carbo Cyphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphono Enyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallylphenyl group, 2- Examples thereof include a methylpropenylphenyl group, a 2-propynylphenyl group, a 2-butynylphenyl group, and a 3-butynylphenyl group.

Next, A in the general formula (1) will be described. A represents an aromatic ring or a hetero ring which may have a substituent. Specific examples of the aromatic ring or hetero ring which may have a substituent include R ₁ and R in the general formula (1). similar to those described in ₂ and R ₃ can be exemplified.

  The sensitizing dye represented by the general formula (1) of the present invention includes an acidic nucleus as shown above, an acidic nucleus having an active methylene group, a substituted or unsubstituted aromatic ring or heterocyclic ring. These can be synthesized by referring to Japanese Patent Publication No. 59-28329.

  Preferred specific examples (D1) to (D38) of the compound represented by the general formula (1) are shown below. In addition, an isomer with a double bond connecting an acidic nucleus and a basic nucleus is not limited to either isomer.

Next, a sensitizing dye having spectral sensitivity in the wavelength range from 760 nm to 1100 nm will be described.
When the polymerizable photosensitive layer of the present invention is recorded with a laser emitting infrared rays, it is preferable to add a compound that generates heat by infrared exposure (hereinafter referred to as an infrared absorber as appropriate). The infrared absorbing agent has a function of converting absorbed infrared rays into heat, and the radical generator is decomposed by the heat generated at this time to generate radicals. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 nm to 1100 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, and metal thiolate complexes. Examples of preferred dyes include cyanine dyes described in JP-A Nos. 58-125246, 59-84356, 59-5929, 60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, JP-A-58-224793, Naphthoquinone dyes described in JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., JP-A-58-112792 And the cyanine dyes described in British Patent 434,875.

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted aryl benzoates described in US Pat. No. 3,881,924 are also preferably used. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A Nos. 58-181051, 58-220143, 59- No. 41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and Pyrlium compounds described in JP-A-59-216146. In US Pat. No. 4,283,475, the pentamethine thiopyrylium salt, etc., and Japanese Patent Publication Nos. 5-13514 and 5-19702 are disclosed. Pyrylium compounds are also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993. Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Further, a cyanine dye is preferable, and a cyanine dye represented by the following general formula (I) is most preferable.

In the general formula (I), X ¹ represents a halogen atom, X ² -L ¹ or NL ² L ³ . Here, X ² represents an oxygen atom or a sulfur atom, L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, and L ² and L ³ are each independently a hydrocarbon having 1 to 12 carbon atoms. Indicates a group. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.
Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Z ¹⁻ represents a counter anion. However, Z ^1- is not necessary when any of R ^{1 to} R ⁸ is substituted with a sulfo group. Preferred Z ¹⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of storage stability of the photosensitive layer coating solution. Hexafluorophosphate ion and aryl sulfonate ion.

  In the present invention, specific examples of the cyanine dye represented by formula (I) that can be suitably used include the following [IR-1] to [IR-12]. It is not limited.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Details of these pigments are described in detail in paragraphs [0052] to [0054] of JP-A-10-39509, and these can also be applied to the present invention. Among these pigments, carbon black is preferable.

These sensitizing dyes are preferably used in the range of 1.0 to 10.0% by mass of the total components of the polymerizable photosensitive layer.

(Photopolymerization initiator)
Next, the photopolymerization initiator contained in the polymerizable photosensitive layer used in the present invention will be described. Examples of the photopolymerization initiator contained in the polymerizable photosensitive layer used in the present invention include various photopolymerization initiators known in patents, literatures, etc., or a combination system of two or more photopolymerization initiators (photo A polymerization initiation system) can be appropriately selected and used. In the present invention, a photopolymerization initiator used alone and a system in which two or more photopolymerization initiators are used in combination are collectively referred to as a photopolymerization initiator.
For example, when light near 400 nm is used as a light source, benzyl, benzoyl ether, Michler's ketone, anthraquinone, thioxanthone, acridine, phenazine, benzophenone, and the like are widely used.

Also, various photopolymerization initiators have been proposed when using visible light of 400 nm or more as a light source. For example, some photoreductive properties described in US Pat. No. 2,850,445 are described. Dyes, such as rose bengal, eosin, erythrosine, etc., or a combination of a dye and a photopolymerization initiator, such as a complex initiation system of a dye and an amine (Japanese Patent Publication No. 44-20189), hexaarylbiimidazole and a radical A combination system of a generator and a dye (Japanese Patent Publication No. 45-37377), a system of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (Japanese Patent Publication Nos. 47-2528 and 54-155292), Cyclic cis-α-dicarbonyl compound and dye system (Japanese Patent Laid-Open No. 48-84183), cyclic triazine and merocyanine dye System (Japanese Patent Laid-Open No. 54-151024), a system of 3-ketocoumarin and an activator (Japanese Patent Laid-Open Nos. 52-112681, 58-15503), a system of biimidazole, styrene derivative, thiol ( JP-A-59-140203), organic peroxide and dye system (JP-A-59-1504, JP-A-59-140203, JP-A-59-189340, JP-A-62-174203) JP-B-62-1641, U.S. Pat. No. 4,766,055), dyes and active halogen compounds (JP-A 63-178105, JP-A 63-258903, JP-A 2 -63054, etc.), dye and borate compound systems (JP-A-62-143044, JP-A-62-1050242, JP-A-64-13140, JP-A-64-13141, JP-A-64-13142, JP-A-64-13143, JP-A-64-13144, JP-A-64-17048, JP-A-1-229003, JP-A-1-298348, JP-A-1- No. 138204, etc.), a dye having a rhodanine ring and a radical generator (JP-A-2-17943, JP-A-2-244050).
Furthermore, a titanocene compound is mentioned as a preferable photoinitiator. As the titanocene compound, for example, known compounds described in JP-A Nos. 59-152396 and 61-151197 can be appropriately selected and used.

  Specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5, 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4-difluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2, 3, 5, 6 Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- ( Pyrid-1-yl) phenyl) titanium and the like.

  In addition, it is preferable that these photoinitiators are used in the range of 0.5-10.0 mass% of all the components of a polymerizable photosensitive layer.

[Addition polymerizable compound having an ethylenically unsaturated double bond]
The addition polymerizable compound having an ethylenically unsaturated double bond contained in the polymerizable photosensitive layer used in the present invention is a compound having at least one ethylenically unsaturated double bond group, preferably two or more. You can select any of them.
For example, it has a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof.
Examples of monomers and copolymers thereof include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) with aliphatic polyhydric alcohol compounds, unsaturated Examples include amides of carboxylic acids and aliphatic polyvalent amine compounds.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, Examples include polyester acrylate oligomers.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p (3-methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.
Furthermore, the mixture of the above-mentioned ester monomer can also be mention | raise | lifted.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-A-48-64183, JP-B-49-43191, JP-B-52-30490 are described. Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid can be used. Furthermore, Journal of Japan Adhesion Association Vol. 20, no. 7, pages 300 to 308 (1984), those introduced as photocurable monomers and oligomers can also be used.

  Specifically, NK oligo U-4HA, U-4H, U-6HA, U-108A, U-1084A, U-200AX, U-122A, U-340A, U-324A, UA-100 (above, new Nakamura Chemical Co., Ltd.), UA-306H, AI-600, UA-101T, UA-101I, UA-306T, UA-306I (above, manufactured by Kyoeisha Yushi), Art Resin UN-9200A, UN-3320HA, UN-3320HB , UN-3320HC, SH-380G, SH-500, SH-9832 (manufactured by Negami Kogyo Co., Ltd.) and the like.

  The amount of the addition polymerizable compound having an ethylenically unsaturated double bond is preferably in the range of 5 to 90% by mass, more preferably in the range of 10 to 80% by mass of the total components of the polymerizable photosensitive layer. is there.

[Polymer binder]
In the present invention, a polymeric binder (binder polymer) can be contained in the polymerizable photosensitive layer.
As the polymer binder, an organic polymer polymer that is soluble or swellable in alkaline water is used because it needs to be dissolved in an alkali developer as well as a film-forming agent for the polymerizable photosensitive layer.
Examples of the organic high molecular polymer include various types. Examples of such an organic polymer include addition polymers having a carboxylic acid group in the side chain, such as JP 59-44615, JP-B 54-34327, JP-B 58-12577, JP-B 54-. No. 25957, JP 54-92723, JP 59-53836, JP 59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Cyclic acid anhydrides for acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, acidic cellulose derivatives having a carboxylic acid group in the side chain, and addition polymers having a hydroxyl group Products, polyvinyl pyrrolidone, polyethylene oxide, and alcohol-soluble polyamide or 2,2-bis- (4-hydride) that can increase the strength of the cured film Kishifeniru) - and a polyether of propane and epichlorohydrin.

Among these, [benzyl (meth) acrylate / (meth) acrylic acid / other addition-polymerizable vinyl monomers as required] copolymer and [allyl (meth) acrylate / (meth) acrylic acid / as required Other addition polymerizable vinyl monomers] copolymers are particularly preferred.
Furthermore, JP-B-7-120040, JP-B-7-120041, JP-B-7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A-1 Polyurethane resins described in JP-A Nos. -271741 and JP-A No. 11-352691 can also be used in the application of the present invention.

  These polymer polymers can improve the strength of the cured film by introducing a radical reactive group into the side chain. Examples of functional groups capable of undergoing addition polymerization include ethylenically unsaturated bond groups, amino groups, and epoxy groups, and examples of functional groups that can become radicals upon irradiation with light include mercapto groups, thiol groups, halogen atoms, and triazines. Structure, onium salt structure and the like, and polar groups include a carboxyl group and an imide group. The functional group capable of addition polymerization is particularly preferably an ethylenically unsaturated bond group such as an acryl group, a methacryl group, an allyl group, or a styryl group, but an amino group, a hydroxy group, a phosphonic acid group, a phosphoric acid group, or a carbamoyl group. A functional group selected from a group, an isocyanate group, a ureido group, a ureylene group, a sulfonic acid group, and an ammonio group can also be used.

In order to maintain the developability of the polymerizable photosensitive layer, the polymer binder used preferably has an appropriate molecular weight and acid value, and has a weight average molecular weight of 5,000 to 300,000 and an acid value of 1.5 to 3. A high molecular weight polymer of 0 meq / g is particularly preferable.
These polymer binders can be contained in an arbitrary amount in the polymerizable photosensitive layer. However, if it exceeds 90% by mass, it may not give a preferable result in terms of formed image strength and the like. , Preferably 10 to 90 mass%, more preferably 30 to 80 mass%.
Further, the use ratio of the addition polymerizable compound having an ethylenically unsaturated double bond and the polymer binder is preferably in the range of 0.1 to 1.5, more preferably the former / the latter in terms of mass ratio. Is 0.1 to 1.0, and most preferably 0.1 to 0.8.

  In addition, the polymerizable photosensitive layer used in the present invention has an ethylenically unsaturated double bond during production or storage of the composition for forming the polymerizable photosensitive layer, in addition to the above basic components. In order to prevent unnecessary thermal polymerization of the addition polymerizable compound, it is desirable to add a small amount of a thermal polymerization inhibitor. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- Butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass of the total components of the composition. If necessary, in order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenic acid amide are added and unevenly distributed on the surface of the polymerizable layer in the drying process after coating. Also good. The amount of the higher fatty acid derivative added is preferably about 0.5% by mass to about 10% by mass of the total components of the composition.

Further, a coloring agent may be added for the purpose of coloring the polymerizable photosensitive layer. Examples of the colorant include phthalocyanine pigments (CI Pigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, There are azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the dye and the pigment is preferably about 0.5% by mass to about 5% by mass of the total components of the composition.
In addition, in order to improve the physical properties of the cured film, an additive such as an inorganic filler or a plasticizer such as dioctyl phthalate, dimethyl phthalate, or tricresyl phosphate may be added. These additives are preferably 10% by mass or less of the total components of the composition.
In addition, a surfactant can be added to the composition for forming the polymerizable photosensitive layer in order to improve the coating surface quality. Suitable surfactants include, for example, fluorine-based nonionic surfactants.

In the present invention, the composition for forming the polymerizable photosensitive layer is coated on a support subjected to various surface treatments as desired as described above. When coating, it is used by dissolving in various organic solvents. Solvents that can be used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether. , Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether , Diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are ethyl and the like. These solvents can be used alone or in combination. In addition, 1-50 mass% is suitable for solid content concentration in a coating solution.
The coverage of the polymerizable photosensitive layer in the lithographic printing plate precursor used in the present invention is preferably in the range of about 0.1 g / m ² ~ about 10 g / m ² in weight after coating and drying, and more preferably 0.3 -5 g / m ² , more preferably 0.5-3 g / m ² .

[Plate making process]
Next, the plate making method of the planographic printing plate of the present invention will be described in detail. In the lithographic printing plate precursor exposure method described above, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 5 to 30 mW) is suitable as a light source in terms of wavelength characteristics and cost. Further, FD-YAG, Ar ⁺ thermal laser may be used.

  The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. After the image exposure, the entire surface may be heated between exposure and development as necessary. By such heating, an image forming reaction in the polymerizable photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur.

(Developer)
The developer used in the plate making method of the lithographic printing plate is not particularly limited. For example, a developer containing an inorganic alkali salt and a nonionic or anionic surfactant is preferably used.
The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogen carbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

When silicate is used, silicon oxide SiO ₂ and alkali oxide M ₂ which are components of silicate are used.
By adjusting the mixing ratio and concentration with O (M represents an alkali metal or ammonium group), the developability can be easily adjusted. Among the alkali aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 2 0.0 is preferred. The amount of the mixture of SiO ₂ and M ₂ O added is preferably 1 to 10% by mass, more preferably 3 to 8% by mass, and most preferably 4 to 7% by mass with respect to the mass of the alkaline aqueous solution. When this concentration is 1% by mass or more, developability and processing capacity are not lowered, and when it is 10% by mass or less, it is difficult to form precipitates and crystals, and further, it is difficult to gel during neutralization in the waste liquid. Does not interfere with waste liquid treatment.

  Further, an organic alkali agent may be supplementarily used for the purpose of finely adjusting the alkali concentration and assisting the solubility of the polymerizable photosensitive layer. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

  The surfactant can be used as appropriate. For example, nonionic or anionic surfactants having a polyoxyalkylene ether group, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate Nonionic surfactants such as sorbitan alkyl esters such as rate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, monoglyceride alkyl esters such as glycerol monostearate and glycerol monooleate; dodecylbenzene Alkylbenzene sulfonates such as sodium sulfonate, sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, hexyl naphthalene Alkyl naphthalene sulfonates such as sodium sulfonate, sodium octyl naphthalene sulfonate, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, sulfosuccinate ester salts such as sodium dilauryl sulfosuccinate, etc. Examples of anionic surfactants include alkylbetaines such as lauryl betaine and stearyl betaine, and amphoteric surfactants such as amino acids. Nonionic and anionic surfactants having a polyoxyalkylene ether group are particularly preferred. is there.

As the nonionic surfactant containing a polyoxyalkylene ether group, those having the structure of the following general formula (II) are preferably used.
R ₄₀ —O— (R ₄₁ —O) _pH (II)

In the formula, R ₄₀ has an optionally substituted alkyl group having 3 to 15 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, or a substituent. An optionally substituted heteroaromatic cyclic group having 4 to 15 carbon atoms (in addition, an alkyl group having 1 to 20 carbon atoms, a halogen atom such as Br, Cl, or I, an aromatic hydrocarbon having 6 to 15 carbon atoms) Group, an aralkyl group having 7 to 17 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, and an acyl group having 2 to 15 carbon atoms), and R ₄₁ is C1-C100 alkylene group which may have a substituent (In addition, as a substituent, a C1-C20 alkyl group and a C6-C15 aromatic hydrocarbon group are mentioned.). P represents an integer of 1 to 100.

  In the definition of the above formula (II), specific examples of the “aromatic hydrocarbon group” include phenyl group, tolyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group and the like, and “heteroaromatic ring” Specific examples of the “group” include furyl group, thionyl group, oxazolyl group, imidazolyl group, pyranyl group, pyridinyl group, acridinyl group, benzofuranyl group, benzothionyl group, benzopyranyl group, benzooxazolyl group, benzoimidazolyl group, and the like. It is done.

In addition, the part of (R ₄₁ —O) _{p in} the formula (II) may be two or three groups within the above range. Specific examples include random or block combinations of ethyleneoxy and propyleneoxy groups, ethyleneoxy and isopropyloxy groups, ethyleneoxy and butyleneoxy groups, ethyleneoxy groups and isobutylene groups, and the like. . In the present invention, the surfactant having a polyoxyalkylene ether group is used alone or in a complex system, and it is effective to add 1 to 30% by mass, more preferably 2 to 20% by mass in the developer. .

Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the above formula (II) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether and polyoxyethylene stearyl ether. Polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether and polyoxyethylene naphthyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Kind.
These surfactants can be used alone or in combination. Further, the content of these surfactants in the developer is preferably in the range of 0.1 to 20% by mass in terms of active ingredients.

  The anionic surfactant containing a polyoxyalkylene ether group is a compound represented by the following formulas (IA) and (IB).

(In the above formula, R ₃ and R ₅ each represent a linear or branched alkylene group having 1 to 5 carbon atoms; R ₄ and R ₆ are a linear or branched alkylene group having 1 to 20 carbon atoms; P and q each represent 0, 1 or 2; Y ₁ and Y ₂ each represent a single bond or an alkylene group having 1 to 10 carbon atoms; n and m each represents an integer of 1 to 100; And when n and m are 2 or more, R ₃ or R ₅ may be selected from two or more groups).

In a preferred embodiment of the present invention, in the above formula, preferred examples of R ₃ and R ₅ include —CH ₂ —, —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, more preferably -CH ₂ CH ₂ - and the like.
Preferred examples of R ₄ and R ₆ include CH ₃ , C ₂ H ₅ , C ₃ H ₇ , and C ₄ H ₉ . Further, p and q are preferably 0 or 1. Y ₁ and Y ₂ are each preferably a single bond. N and m are each preferably an integer of 1 to 20.

The addition amount of the above compound is suitably 1 to 10% by mass in the developer, and it is effective to add 2 to 10% by mass.
If the addition amount is too small, the developability and the solubility of the photosensitive layer components are lowered. On the other hand, if the addition amount is too large, the printing durability of the printing plate is lowered.

  The pH of the developer used for the plate making of the lithographic printing plate of the present invention is not particularly limited, but is preferably 9.0 to 12.7, and more preferably 9.5 to 12.5. If it is 9.0 or more, image formation can be ensured, and if it is 12.7 or less, over-development is not caused, and damage due to development of the exposed portion is not caused.

The development of the lithographic printing plate in the present invention is carried out at a temperature of about 0 to 60 ° C., preferably about 15 to 40 ° C., for example, by immersing the exposed lithographic printing plate in a developer and rubbing with a brush according to a conventional method. Do.
Further, when developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored by using a replenishing solution or a fresh developing solution.
The lithographic printing plates thus developed are washed with water, surfactants, etc. as described in JP-A Nos. 54-8002, 55-1115045, 59-58431, etc. And a desensitizing solution containing gum arabic, starch derivatives and the like. In the present invention, these treatments can be used in various combinations for the post-treatment of the planographic printing plate.

  Further, for the purpose of improving the image strength and printing durability, it is also effective to carry out whole surface post-heating or whole surface exposure on the developed image. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC.

  The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
[Example 1]
[Support Example 1]
(Support 1: Anodized aluminum support)
An aluminum plate made of material 1S having a thickness of 0.30 mm was used with a No. 8 nylon brush and an aqueous suspension of 800 mesh Pamiston, and its surface was grained and washed thoroughly with water. After etching by immersing in 10% sodium hydroxide at 70 ° C. for 60 seconds, washed with running water, neutralized with 20% HNO ₃ and washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% nitric acid aqueous solution with a anodic electricity amount of 300 coulomb / dm ² using a sinusoidal alternating current under the condition of VA = 12.7V. When the surface roughness was measured, it was 0.45 μm (Ra indication). Next, after dipping in a 30% H ₂ SO ₄ aqueous solution and desmutting at 55 ° C. for 2 minutes, a cathode was placed on the grained surface in 33 ° C., 20% H ₂ SO ₄ aqueous solution to obtain a current density. When anodized at 5 A / dm ² for 50 seconds, the thickness was 2.6 g / m ² . This was designated as Support 1.

(Support 2)
The following polymer (P1) solution (undercoat liquid) was applied to the support 1 using a bar coater so that the dry coating amount was 2 mg / m ^2, and dried at 80 ° C. for 20 seconds.

[Undercoat liquid]
Polymer (P1) 0.3g
60.0g of pure water
Methanol 939.7g

    Structural formula of polymer (P1)

[Polymerizable photosensitive composition P-1]
A photosensitive layer (1) having the following composition was coated on the support 2 using a bar coater and then dried at 100 ° C. for 1 minute. The mass of the photosensitive composition after drying was 1.1 g / m ² .

Photosensitive layer (1)
Ethylenically unsaturated bond-containing compound (A1) 1.0 part by weight Polymer binder (B1) 2.0 part by weight Sensitizing dye (D29) 0.15 part by weight Photopolymerization initiator (C1) 0.12 part by weight ε -Phthalocyanine (F1) dispersion 0.02 parts by mass Sensitization aid (G1) 0.5 parts by mass Fluorine nonionic surfactant Megafac F-780F
(Dai Nippon Ink Chemical Co., Ltd.) 0.02 parts by mass Methyl ethyl ketone 26.0 parts by mass Propylene glycol monomethyl ether 26.3 parts by mass

  The ethylenically unsaturated bond-containing compound (A1), polymer binder (B1), photopolymerization initiator (C1), and ε-phthalocyanine (F1) used in the photopolymerizable photosensitive composition P-1 ), The sensitization aid (G1) was a compound of the following chemical formula. As the sensitizing dye, (D29) shown in the specific example was used.

On this photosensitive layer,
Kuraray Co., Ltd. KL-118 5.0 parts by mass EMALEX 710 (Nippon Emulsifier Co., Ltd. nonionic surfactant) 0.09 parts by mass Pure water 94.91 parts by mass An aqueous solution for protective layer consisting of 94.91 parts by mass has a dry coating mass of 2. It was applied with a bar coater so as to be 5 g / m ² and dried at 120 ° C. for 1 minute to obtain a photosensitive lithographic printing plate precursor.

(Exposure, plate making)
Was loaded on the above photosensitive lithographic printing plate precursor FUJIFILM Electronic Imaging Ltd made Violet semiconductor laser setter Vx9600 (InGaN-based semiconductor laser 405 nm ± 10 nm emission / output 30 mW), an exposure amount of 90μJ / cm ^2, at a resolution 2,438 dpi, the image An image with an area ratio of 22% was drawn. The plate after exposure is automatically sent to the automatic processor LP1250PLX from which the pre-water washing bath is removed from the connected automatic processor, heated at 150 ° C. for 10 seconds, and subsequently developed at 28 ° C. for 20 seconds. The The developer was prepared by diluting a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water. The developed plate was rinsed in a rinse bath, sent to a gumming bath, and a solution obtained by diluting a gum solution FP-2W manufactured by Fuji Photo Film Co., Ltd. with water twice. The plate after gumming was discharged after drying with hot air to obtain a planographic printing plate P-1.

(Processability evaluation)
The photosensitive lithographic printing plate was processed with 50 plates per day (1030 × 800 mm size) for 60 days, the developing solution was drained, and the state of precipitation in the developing bath tank was observed. The deposits deposited on days 1, 15, 30, and 60 were evaluated as x, and those not deposited were evaluated as ◯.

(Evaluation of adhesion of PVA residue on plate)
The photosensitive lithographic printing plate was processed for 60 days with 50 plates per day (1030 × 800 mm size), and the PVA gelled product on the plate was processed on the first day of the processing on days 1, 15, 30, and 60. The number of adhesions was counted, and the average number of adhesions per plate was calculated.

[Examples 2-3]
Instead of KL-118 used in the protective layer of Example 1, lithographic printing plates P-2 to P-3 were prepared in the same manner as in Example 1 except that KM-106 and KM-118 manufactured by Kuraray Co., Ltd. were used. Obtained.

[Comparative Example 1]
P-4 was obtained in the same manner as in Example 1 except that Kuraray Co., Ltd. highly saponified polyvinyl alcohol PVA-105 was used instead of KL-118 used in the protective layer of Example 1.

Example 4
A lithographic printing plate P-5 was obtained in the same manner as in Example 1 except that SK-5102 manufactured by Kuraray Co., Ltd. was used instead of KL-118 used in the protective layer of Example 1.

Example 5
A photosensitive layer coating solution P-6 having the following composition was coated on the undercoated support 2 prepared in Example 1 using a wire bar. Drying was performed at 122 ° C. for 43.5 seconds using a hot air drying apparatus to form a photosensitive layer. The coating amount after drying was 1.4 g / m ² .

Photosensitive layer coating solution P-6
Infrared absorber (IR-1) 0.08 g
Polymerization initiator (OS-1) 0.25 g
Dipentaerythritol hexaacrylate 1.00g
Binder polymer (BT-1) 1.00g
0.04g of ethyl violet chloride salt
Fluorosurfactant 0.03g
(Megafuck F-780-F, manufactured by Dainippon Ink & Chemicals, Inc.)
Methyl ethyl ketone 10.4g
4.83 g of methanol
1-methoxy-2-propanol 10.4 g

  The structures of the infrared absorber (IR-1), the polymerization initiator (OS-1) and the binder polymer (BT-1) used in the photosensitive layer coating solution are shown below.

On this photosensitive layer, the same protective layer as in Example 1 was coated to obtain a lithographic printing plate precursor P-6.
The obtained lithographic printing plate precursor was drawn with a Trendsetter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser, with an outer drum rotating speed of 150 rpm and a resolution of 2438 dpi, and an image area ratio of 22%. After the exposure, the developer DH-N manufactured by Fuji Photo Film Co., Ltd. was diluted 5 times using LP-1310HII manufactured by Fuji Photo Film Co., Ltd. and developed at 30 ° C. for 12 seconds. The finisher used the 1: 1 water dilution of FP-2W manufactured by Fuji Photo Film Co., Ltd. to obtain a lithographic printing plate P-6.

  A summary of the used modified or unmodified polyvinyl alcohol is shown in Table 3 below.

  The evaluation results are shown in Table 4.

  From the results of Table 4, the lithographic printing plates of Examples 1 to 5 provided with the protective layer in the present invention are excellent in processability, but do not have acid residues or acid residue salts in the molecule. It can be seen that the lithographic printing plate of Comparative Example 1 using alcohol is inferior.

Claims (3)

  A lithographic printing plate precursor comprising a lithographic printing plate precursor comprising a polymerizable photosensitive layer and a protective layer laminated in this order on a support, imagewise exposed and developed with an aqueous alkali solution, the lithographic printing plate making method comprising: A lithographic printing plate characterized in that the protective layer contains polyvinyl alcohol having an acid group or an acid group salt in the molecule, and the protective layer is eluted and removed in an alkaline aqueous solution during the development processing step. Plate making method.   The lithographic printing plate making method according to claim 1, wherein the acid group constituting the acid group or the salt of the acid group is a carboxylic acid or a sulfonic acid.   The lithographic printing plate making method according to claim 1 or 2, wherein the imagewise exposure is exposure with a laser having an emission wavelength in a range of 300 nm to 1100 nm.