JP2006065061A - Photosensitive lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photopolymerizable photosensitive lithographic printing plate suitable for drawing with laser light and giving good uniformity in screen tint unevenness of halftone in high-definition AM screen printing with ≥200 screen lines or FM screen printing, particularly FM screen printing. <P>SOLUTION: In the photosensitive lithographic printing plate which has at least one polymerizable photosensitive layer on a hydrophilic support and is subjected to laser exposure, an unexposed portion of the photosensitive layer satisfies 2≤t≤30 wherein t is a time (second) in which the unexposed portion is thoroughly removed by dissolution in an alkaline aqueous developer of ≤pH 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive lithographic printing plate, and more particularly to a photosensitive lithographic printing plate suitable for drawing with a laser beam and suitable for high-definition AM screen printing or FM screen printing having a screen line number of 200 lines or more.

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 surface without using a lith film by scanning the plate surface according to digitized image information with highly directional light such as laser light by 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 the laser beam 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 polymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system).

However, since the photosensitive lithographic printing plate as described above is drawn with a laser beam, the edge of the image depends on the shape of the energy distribution of the laser beam, and an insufficiently polymerized region is formed due to an insufficient exposure amount. . For this reason, the sharpness of the image edge is impaired, leading to a decrease in resolution. In addition, such poorly polymerized image edges have poor removal due to the alkali concentration of the developer and the state of the developing brush in the development processing step, and the in-plane variation in the halftone dot area of the plate making plate is increased. It was.
Furthermore, since such a printing plate uses a support having irregularities formed on the surface by electrolytic treatment or brushing to ensure hydrophilicity as a support, it is further caused by scattering of reflected light during laser exposure. Image quality and sharpness are impaired, and the reproducibility of the shadow portion is greatly reduced.

  On the other hand, in recent years, the demand for high-definition AM screen printing and FM screen printing has increased in the CTP technology, and the resolution of the planographic printing plate has become an important performance.

  An FM (Frequency Modulation) screen is one in which minute halftone dots of about 20 microns are randomly arranged regardless of the screen angle and the number of lines, and density gradation is expressed by the density of halftone dots per unit area. Features of this FM screen printed matter include no interference moiré or rosette pattern, no tone jump in the halftone area near 50%, and halftone dots are small. The colors appear bright.

  An AM (Amplitude Modulation) screen is a screen in which halftone dots are regularly arranged at an angle with respect to the FM screen and the density gradation is expressed by the size of the halftone dots per unit area. The number of AM screen lines in Japan is 175 lines per inch. On the other hand, what uses a screen line number of 200 lines or more is generally called high definition.

  Features of high-definition printed materials include a reduction in moire and rosetta patterns, an improvement in image texture, a sense of existence, and an improvement in reproducibility of details.

  However, in order to provide a printing plate suitable for FM screen and high-definition AM screen printing, a photosensitive material that reduces the reproducibility of a shadow portion such as a lithographic printing plate using the polymerizable photosensitive layer described above. Cannot reproduce extremely fine halftone dots and was difficult to use.

  In Patent Document 1 (Japanese Patent Laid-Open No. 2003-43703), an intermediate layer containing a polymer compound having a structural unit having a sulfonic acid group in the side chain is provided on a support, and a polymerizable feeling is provided thereon. Although a photosensitive lithographic printing plate provided with an optical layer has been disclosed, it is not yet sufficient as a plate material suitable for high-definition AM screen printing or FM screen printing, and in particular, unevenness of the flat net on the FM screen is present. Intense and difficult to use FM screen.

JP 2003-43703 A

  The object of the present invention is a photopolymerization suitable for drawing with a laser beam and having good uniformity of halftone flat screen unevenness using high-definition AM screen printing and FM screen printing with a screen line number of 200 lines or more, especially using an FM screen. Is to provide a type photosensitive lithographic printing plate.

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. In a photosensitive lithographic printing plate having at least one polymerizable photosensitive layer on a hydrophilic support and exposed with a laser, the non-exposed portion of the photosensitive layer is completely dissolved in an alkaline aqueous developer having a pH of 13 or less. A photosensitive lithographic printing plate satisfying 2 ≦ t ≦ 30 when the removal time is t seconds.

2. ^2. The photosensitive lithographic printing plate as described in 1 above, wherein the coating amount of the photosensitive layer is from 0.5 g / m ² to 3.0 g / m ² .

3. The photosensitive layer contains the following components (A), (B), (C) and (D), and the mass ratio of the component (C) to the component (D) is (C). The photosensitive lithographic printing plate as described in 1 or 2 above, wherein / D is 1.5 or less.
(A) a sensitizing dye having an absorption maximum in a wavelength range of 360 nm to 450 nm,
(B) a polymerization initiator,
(C) an addition polymerizable compound having an ethylenically unsaturated double bond, and (D) a binder polymer

  4). 4. The photosensitive lithographic printing plate as described in 3 above, wherein the binder polymer has at least a structural unit represented by the following formulas (1) to (3).

In the formula, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C1 to C6 alkyl group, and X represents —COOH, —CO—W ₁ —L ₁ —COOH, or —SO _3. A functional group selected from H, W ₁ represents an oxygen atom, a sulfur atom, or —NH— group, L ₁ represents a divalent organic group, and Y represents —CO—O—CH ₂ —CH═CH. ₂ groups, —CO—W ₂ —L ₂ —O—CO—CR ₄ ═CH ₂ group, W ₂ represents an oxygen atom, sulfur atom, or —NH— group, and L ₂ represents a divalent organic group. R ₄ represents a hydrogen atom or a C1 to C6 alkyl group, W ₃ represents an oxygen atom, a sulfur atom, or a —NH— group, R ₅ represents a C1 to C18 alkyl group, C5 to C20 An alkyl group having an alicyclic structure or a group having a C6 to C20 aromatic ring is shown.

  According to the present invention, photopolymerization that is suitable for drawing with laser light and has good uniformity of halftone flat screen unevenness using high-definition AM screen printing and FM screen printing with a screen line number of 200 lines or more, especially using an FM screen. A type photosensitive lithographic printing plate is provided.

[Measurement of time taken to dissolve and remove non-exposed portion of photosensitive layer]
In the photosensitive lithographic printing plate of the present invention, when the time during which the non-exposed portion of the photosensitive layer is completely dissolved and removed in an alkaline aqueous developer having a pH of 13 or less (hereinafter referred to as dissolution time) is t seconds, 2 ≦ It is necessary to satisfy t ≦ 30.
The dissolution time is, for example, an aqueous alkaline developer (temperature 28 ° C.) adjusted to a pH of 13 or less, preferably pH 12.5 to 10.0 in the developer composition described later, and a photosensitive layer on the support described later. After immersing the lithographic printing plate coated only with water, washing it with water, measuring the density of the photosensitive layer remaining on the support with a reflection densitometer, the time when it became the same as the density of the support alone t (seconds). In the present invention, the time t seconds is 2 ≦ t ≦ 30, preferably 3 ≦ t ≦ 25, and more preferably 5 ≦ t ≦ 25. If the dissolution time exceeds 30 seconds, the photosensitive layer is not sufficiently removed at the time of exposure and development, and remains on the support, causing smearing of the non-image area at the time of printing. It damages the interface between the layer and the support, and it becomes difficult to sufficiently reproduce a region having a very small image area such as a highlight or a fine line. In addition, as a method for adjusting the dissolution time to the above range, in consideration of the method for adjusting the acid value of the binder polymer in the photosensitive layer within the range described later, and the solubility of the low molecular weight material other than the binder in the developer. Examples thereof include a method for optimizing the mixing ratio with the binder polymer.

[Photosensitive planographic printing plate]
Next, the structure of the photosensitive lithographic printing plate (lithographic printing plate precursor) having spectral sensitivity in the wavelength range of 360 nm to 450 nm used in the present invention will be described in order.

[Support]
First, the support for the photosensitive lithographic printing plate 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, etc., 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%, 20 to 100 ° C., and the amount of aluminum dissolved 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 the graining treatment and the anodizing treatment. 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. The support used in the present invention may be subjected to a surface treatment such as a treatment other than a silicate treatment with an alkali metal silicate, for example, an immersion treatment in an aqueous solution of potassium fluorinated zirconate or phosphate.

  In the present invention, a polymerizable photosensitive layer made of, for example, a photosensitive composition is coated on a support (in the case of aluminum, aluminum that has been appropriately surface-treated as described above), and then a protective layer is formed. The photosensitive lithographic printing plate is formed by coating, but an organic or inorganic undercoat layer may be provided as needed before coating the polymerizable photosensitive layer, or JP-A-7-159983. A sol-gel treatment in which a functional group capable of causing an addition reaction by a radical is disclosed as disclosed in Japanese Patent Publication No. Gazette 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. A yellow dye can also be added to improve the tone reproducibility of the photopolymerization type photosensitive lithographic printing plate.
The coating amount after drying of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . Sufficient printing durability can be obtained within the above range.

  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. .

(Photosensitive layer)
The photosensitive layer of the photosensitive lithographic printing plate used in the present invention has spectral sensitivity in a wavelength region of at least 360 nm to 450 nm. A photosensitive lithographic printing plate comprising the following (A) to (D) is preferred.
(A) a sensitizing dye having an absorption maximum in a wavelength range of 360 nm to 450 nm,
(B) a polymerization initiator, preferably a titanocene compound,
(C) an addition polymerizable compound having an ethylenically unsaturated double bond, and (D) a binder polymer.
These will be described sequentially.

[(A) Sensitizing dye]
The sensitizing dye used in the photosensitive lithographic printing plate used in the present invention is a sensitizing dye having an absorption maximum in a wavelength region of 360 nm to 450 nm. 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-dialkylsulfate 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), dialkyl phosphonooxy 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 constitute the basic nucleus in merocyanine dyes described in, for example, LGBrooker et al., J. Am. Chem. Soc., 73, 5326-5358 (1951). Any known material 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-chloro Benzoki Sol, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazoles (eg, naphtho [1,2] oxazole, naphtho [2,1] oxazole, etc.), selenazoles (eg, , 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazoles (for example, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselena) Sol etc.), naphthoselenazoles (eg naphtho [1,2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), 2-quinolines (eg Quinoline, 3-methyl Norin, 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,- Trimethylindolenine etc.), 2-pyridines (eg pyridine, 5-methylpyridine etc.), 4-pyridine (eg pyridine etc.) and 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 aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, a halogen atom, or a carboxyl group.

More preferred 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 group Examples of these include ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group and the like. Examples of G1 in the acyl group (G1CO-) 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 (D39) 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.

  These sensitizing dyes are preferably used in the range of 1.0 to 10.0% by mass of the total components of the photosensitive layer. More preferably, it is the range of 1.0-5.0 mass%.

[(B) polymerization initiator]
Next, the polymerization initiator contained in the photosensitive layer used in the present invention will be described. As the polymerization initiator contained in the photosensitive layer used in the present invention, various polymerization initiators known in patents, literatures, etc., or a combination system of two or more polymerization initiators (photopolymerization initiation system) are used. It can be appropriately selected and used. In the present invention, a polymerization initiator used alone and a system in which two or more polymerization initiators are used in combination are collectively referred to simply as a polymerization 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, lophine dimer, etc. 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 polymerization initiator. 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.

  These polymerization initiators are preferably used in the range of 0.5 to 10.0% by mass of the total components of the photosensitive layer. More preferably, it is the range of 1.0-5.0 mass%.

[(C) Addition polymerizable compound having an ethylenically unsaturated double bond]
The addition-polymerizable compound having an ethylenically unsaturated double bond contained in the photosensitive layer used in the present invention can be selected from compounds having at least one ethylenically unsaturated double bond group, preferably two or more. Can be selected.
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, A polyester acrylate oligomer etc. can be mentioned.

  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- can be mentioned (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 mentioned.

  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 with respect to the total components of the photosensitive layer.

[(D) Binder polymer]
As the binder polymer, an organic high molecular polymer that is soluble or swellable in alkaline water is used because it needs to be dissolved in an alkaline developer as well as a film forming agent for the photosensitive layer.
The binder polymer suitable in the present invention desirably has at least a structural unit represented by the following formulas (1) to (3).

In the above formula, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C1 to C6 alkyl group, and X represents —COOH, —CO—W ₁ —L ₁ —COOH, or —SO ₃ represents a functional group selected from H, W ₁ represents an oxygen atom, a sulfur atom, or —NH— group, L ₁ represents a divalent organic group, and Y represents —CO—O—CH ₂ —CH═. CH ₂ group, —CO—W ₂ —L ₂ —O—CO—CR ₄ ═CH ₂ group, W ₂ represents an oxygen atom, sulfur atom, or —NH— group, and L ₂ represents a divalent organic group. R ₄ represents a hydrogen atom or a C 1 to C 6 alkyl group, W ₃ represents an oxygen atom, a sulfur atom, or a —NH— group, R ₅ represents a C 1 to C 18 alkyl group, C 5 to C 20 Or an alkyl group having an alicyclic structure or a group having an aromatic ring of C6 to C20.

Specific examples of each structural unit represented by the above formulas (1) to (3) are described below, but the present invention is not limited to these structures.
Specific examples of formula (1) include the structural units shown below.

  Specific examples of formula (2) include the structural units shown below.

  Specific examples of the monomer capable of forming the structural unit of the formula (3) include methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, normal butyl (meth) acrylate, isopropyl (meth) acrylate, cyclohexyl Examples include alkyl or aryl (meth) acrylates such as (meth) acrylate, n-hexyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, and phenethyl (meth) acrylate.

  In order to maintain the developability of the photosensitive layer, the binder polymer used in the present invention preferably has an appropriate molecular weight and acid value, and has a mass average molecular weight of 5000 to 300,000 and an acid value of 0.5 to 200. Binder polymers are particularly preferred.

  The combination of the structural units represented by the formulas (1), (2), and (3) may be any combination as long as the molecular weight, acid value, and double bond amount are satisfied. The ratio of the structural units represented by the formulas (1), (2), and (3) is preferably (1) 1 to 70% by mass, (2) 0.5 to 98% by mass, ( 3) The range of 0.5-98 mass% is preferable. Note that structural units other than the above formulas (1) to (3) may be further added as long as the molecular weight, acid value, and double bond amount are satisfied.

  These binder polymers can be contained in an arbitrary amount in the photosensitive layer, but preferably 10 to 90% by mass, more preferably 30 to 80% by mass.

In the present invention, a binder polymer other than the above can be mixed and used.
Examples of the organic polymer include various polymers. When water development is desired, for example, a water-soluble organic polymer is used. 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.
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.

  In the present invention, the ratio of the (C) addition polymerizable compound having an ethylenically unsaturated double bond and the (D) binder polymer is 1.5 or less in mass ratio (C) / (D). Is particularly preferably 0.1 to 1.5, more preferably 0.1 to 1.0, and still more preferably 0.1 to 0.8.

  Further, in the photosensitive layer used in the present invention, in addition to the above basic components, an ethylenically unsaturated double bond during the production or storage of the composition for forming the photosensitive layer (photosensitive composition). It is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the addition-polymerizable compound having. 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 may be added and unevenly distributed on the surface of the photosensitive layer in the drying process after coating. 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 photosensitive composition.

Further, a coloring agent may be added for the purpose of coloring the 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 photosensitive 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 based on the total components of the photosensitive composition.
Further, a surfactant can be added to the composition for forming the photosensitive layer in order to improve the coating surface quality. Suitable surfactants include, for example, fluorine-based nonionic surfactants.

In the present invention, the photosensitive composition is applied onto a support that has been subjected to various surface treatments as desired, but when the photosensitive composition is applied onto a support, Used 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 coating amount of the photosensitive layer used in the present invention is suitably in the range of about 0.5 g / m ² or more and 3.0 g / m ² or less, more preferably 0.7 g / m ^{2 by} weight after coating and drying. ^{It is 2} or more and 2.5 g / m ² or less, more preferably 0.8 g / m ² or more and 2.0 g / m ² or less.

In general, an oxygen-blocking protective layer (overcoat layer) is provided on the photosensitive layer in order 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.
Examples of the water-soluble vinyl polymer contained in the oxygen-blocking protective layer include polyvinyl alcohol and partial esters, ethers, and acetals thereof, or a substantial amount of unsubstituted vinyl alcohol units that make them necessary water-soluble. And a copolymer thereof. Examples of the polyvinyl alcohol include those having a hydrolysis degree of 71 to 100% and a polymerization degree in the range of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA- 203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, L-8 etc. are mentioned. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal and polyvinyl acetal, and copolymers thereof. Other useful polymers include polyvinyl pyrrolidone, gelatin and gum arabic, and these may be used alone or in combination.

As the solvent used for coating the oxygen-blocking protective layer in the photosensitive lithographic printing plate of the present invention, pure water is preferable, but alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone are mixed with pure water. May be. The concentration of the solid content in the coating solution is suitably 1 to 20% by mass. In the oxygen-blocking protective layer of the present invention, known additives such as a surfactant for improving coating properties and a water-soluble plasticizer for improving physical properties of the film may be added. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer may be added. The coating amount is suitably in the range of about 0.1 g / m ² to about 15 g / m ² in terms of the mass after drying. More preferably, it is 1.0 g / m ² to about 5.0 g / m ² .

[Plate making process]
Next, the plate making method of the photosensitive lithographic printing plate of the present invention will be described in detail. In the exposure method of the photosensitive lithographic printing plate 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.

  The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. Moreover, the photosensitive layer component of the photosensitive lithographic printing plate of the present invention can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component. The planographic printing plate can be loaded on a printing press and then subjected to a method such as exposure-development on the press. 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 photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. 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. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC.

(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 surfactant and having a pH of 13 or less is preferably used. More preferably, the pH is 12.5 to 10.0.

  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.

In the case of using silicate, developability can be achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). 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. When the SiO ₂ / M ₂ O is less than 0.5, it 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.

  In addition, an organic alkali agent may be supplementarily used for the purpose of finely adjusting the alkali concentration and assisting the solubility of the 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 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 sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate and sorbitan trioleate, monoglyceride alkyl esters such as glycerol monostearate and glycerol monooleate; dodecylbenzenesulfonic acid Alkylbenzene sulfonates such as sodium, sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, sodium hexyl naphthalene sulfonate Anion interfaces such as alkyl naphthalene sulfonates such as sodium, sodium octyl naphthalene sulfonate, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, and sulfosuccinate esters such as sodium dilauryl sulfosuccinate Activators: Alkyl betaines such as lauryl betaine and stearyl betaine, amphoteric surfactants such as amino acids, and the like can be mentioned. Particularly preferred are nonionic surfactants having a polyoxyalkylene ether group.

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

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 (I), 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} formula (I) 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 composite system, and 1-30% by mass, preferably 2-20% by mass of the developer is added to developability and resistance of the printing plate. Effective in terms of printability.

Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the above formula (I) 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 conductivity of the developer is preferably 3 to 30 mS / cm. If it is 3 mS / cm or more, the photopolymerizable photosensitive layer on the surface of the aluminum support can be surely eluted, and there is no stain on printing, and if it is 30 mS / cm or less, the salt concentration does not become too high. The elution rate of the photopolymerizable photosensitive layer does not become extremely slow, and no remaining film is formed in the unexposed area. Particularly preferred conductivity is in the range of 5-20 mS / cm.

The development of the photosensitive lithographic printing plate in the present invention is carried out according to a conventional method, for example, by immersing the exposed photosensitive lithographic printing plate in a developer at a temperature of about 0 to 60 ° C., preferably about 15 to 40 ° C. For example, rubbing with.
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 photosensitive lithographic printing plate thus developed is washed with water, surface active as described in JP-A Nos. 54-8002, 55-1115045 and 59-58431. It is post-treated with a rinsing solution containing an agent and the like, 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 photosensitive lithographic printing plate.
The printing plate obtained by the above treatment can be improved in printing durability by post-exposure treatment or heating treatment such as burning according to the method described in JP-A-2000-89478.
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.

Examples 1-4
[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)
A solution of the following polymer (P1) 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)

[Photosensitive compositions P-1 to P-3]
A photosensitive composition (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 . In addition, the following B-1 to B-3 was used for the binder polymer.

Ethylenically unsaturated bond-containing compound (A-1) 1.0 part by weight Binder polymer (B-1 to B-3) 1.0 part by weight Sensitizing dye (specific example D30) 0.15 part by weight Polymerization initiator (C-1) 0.12 parts by mass ε-phthalocyanine (F-1) dispersion 0.02 parts by mass Sensitization aid (G-1) 0.5 parts by mass Fluorine-based 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

On this photosensitive layer, the following protective layer aqueous solution was applied with a bar coater so that the dry coating mass was 2.5 g / m ^2, and dried at 120 ° C. for 1 minute to obtain photosensitive lithographic printing plates 1 to 3. It was.

(Aqueous solution for protective layer)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 5.0 parts by mass
EMALEX 710 (Nonionic surfactant manufactured by Nippon Emulsifier Co., Ltd.) 0.09 parts by mass Pure water 94.91 parts by mass

[Photosensitive composition P-4]
Photosensitive lithographic printing plate as in Example 1 except that the exemplified compound (D39) was used as a sensitizing dye, biimidazole manufactured by Kurokin Chemical Co., Ltd. as a polymerization initiator, and mercaptobenzothiazole as a sensitizing aid. 4 was created.

(Measurement of dissolution time)
As a developer, a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. diluted 5 times with water (pH = 11.95) was charged into a beaker, and the photosensitive lithographic printing plates 1 to 4 The sample without the protective layer was immersed and washed with water at different times, and the density of the photosensitive layer remaining on the support was measured with a reflection densitometer. T (seconds) was measured. The results are shown in Table 1.

(Evaluation of flat mesh unevenness)
The above-described photosensitive lithographic printing plate is loaded into a Violet semiconductor laser setter Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) manufactured by FUJIFILM Electronic Imaging Ltd, Fuji Photo with an exposure amount of 90 μJ / cm ² and a resolution of 2438 dpi A 35% flat screen was drawn on a film FM screen, TAFFETA 20. The plate after exposure is automatically sent to the connected automatic processor LP1250PLX (with brush), heated at 100 ° C. for 10 seconds, washed away with PVA protective layer, and subsequently developed at 28 ° C. for 20 seconds. It is processed. 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 on which a flat net was drawn. The area ratio of the obtained flat net of the planographic printing plate was measured using CC-dot, and the maximum and minimum area difference (δdot) was measured. The results are shown in Table 1.

Comparative Example 1
Photosensitive composition P as in Example 1 except that 2.0 parts by mass of the ethylenically unsaturated bond-containing compound (A1) of Example 1 and 1.0 part by mass of B-4 as a binder polymer were used. -5 was prepared, and using the photosensitive lithographic printing plate provided with this as a photosensitive layer, the dissolution time and δdot were measured in the same manner as in Example 1. The results are shown in Table 1.

  It can be seen from Table 1 that the lithographic printing plates obtained in the examples have a good uniformity of flat halftone unevenness because the dissolution time t seconds is appropriately set.

  In addition, the ethylenically unsaturated bond containing compound (A-1) used for preparation of the photosensitive composition of an Example and a comparative example, a polymer binder (B-1 to B-4), a polymerization initiator (C- The structures of 1), ε-phthalocyanine (F-1), and sensitization aid (G-1) are shown below. As the sensitizing dye, (D30) or (D39) shown in the specific examples was used.

Claims (4)

  In a photosensitive lithographic printing plate having at least one polymerizable photosensitive layer on a hydrophilic support and exposed with a laser, the non-exposed portion of the photosensitive layer is completely dissolved in an alkaline aqueous developer having a pH of 13 or less. A photosensitive lithographic printing plate satisfying 2 ≦ t ≦ 30 when the removal time is t seconds. ^2. The photosensitive lithographic printing plate according to claim 1, wherein the coating amount of the photosensitive layer is 0.5 g / m ² or more and 3.0 g / m ² or less. The photosensitive layer contains the following components (A), (B), (C) and (D), and the mass ratio of the component (C) to the component (D) is (C). 3. The photosensitive lithographic printing plate according to claim 1, wherein / (D) is 1.5 or less.
(A) a sensitizing dye having an absorption maximum in a wavelength range of 360 nm to 450 nm,
(B) a polymerization initiator,
(C) an addition polymerizable compound having an ethylenically unsaturated double bond, and (D) a binder polymer The photosensitive lithographic printing plate according to claim 3, wherein the binder polymer has at least a structural unit represented by the following formulas (1) to (3).

In the formula, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C1 to C6 alkyl group, and X represents —COOH, —CO—W ₁ —L ₁ —COOH, or —SO _3. A functional group selected from H, W ₁ represents an oxygen atom, a sulfur atom, or —NH— group, L ₁ represents a divalent organic group, and Y represents —CO—O—CH ₂ —CH═CH. ₂ groups, —CO—W ₂ —L ₂ —O—CO—CR ₄ ═CH ₂ group, W ₂ represents an oxygen atom, sulfur atom, or —NH— group, and L ₂ represents a divalent organic group. R ₄ represents a hydrogen atom or a C1 to C6 alkyl group, W ₃ represents an oxygen atom, a sulfur atom, or a —NH— group, R ₅ represents a C1 to C18 alkyl group, C5 to C20 An alkyl group having an alicyclic structure or a group having a C6 to C20 aromatic ring is shown.