JP2005043724A - Photopolymerizable planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planographic printing plate for laser scanning exposure having excellent workability and economic efficiency and suitable for a CTP (computer-to-plate) system, and moreover, to provide a planographic printing plate which enables drawing with violet laser, which prevents changes (crystallization) in the aggregation state of a sensitizing dye for a long period of time, and which stably shows high sensitivity. <P>SOLUTION: In the photopolymerizable planographic printing plate having a photopolymerizable photosensitive layer on a supporting body, the photopolymerizable photosensitive layer contains: a polymerizable compound having at least an ethylenically unsaturated group; a sensitizing dye; and a binder resin. The sensitizing dye has the absorption maximum in the range of 300 nm to 500 nm and has the solubility parameter (SP value) in the range expressed by ¾SP value of the sensitizing dye - SP value of the mixture of the polymerizable compound having an ethylenically unsaturated group and the binder resin¾≤8 MPa<SP>1/2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer formed on a support. More specifically, the present invention relates to a lithographic printing plate that can be directly made with a laser beam. More specifically, the present invention relates to a lithographic printing plate exhibiting high sensitivity capable of direct plate making with a violet laser of 350 nm to 450 nm.

  Conventionally, PS plates in which an oleophilic photosensitive resin layer is provided on a hydrophilic support are widely used as lithographic printing plates. Usually, exposure (surface exposure) is performed through a lith film to dissolve and remove non-image areas. In this process, a lithographic printing plate having a desired image was obtained.

  In recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread. This technology has also spread to the printing field, and is developed as a CTP technology that scans highly directional light such as laser light in accordance with digitized image information and directly produces a printing plate without going through a lith film. ing.

  As one of such lithographic printing plates capable of scanning exposure, conventionally, a photopolymerizable composition having high sensitivity as an ink-receptive photosensitive resin layer (hereinafter referred to as a photosensitive layer) provided on a hydrophilic support. Printing plates using products are already on the market, have a simple development process, and are excellent in resolution, inking properties, printing durability, and stain resistance.

  The photopolymerizable composition basically comprises an ethylenically unsaturated compound, a photopolymerization initiation system, and a binder resin. Image formation is performed by the photoinitiation system absorbing light and generating active radicals. It causes addition polymerization and causes insolubilization of the photosensitive layer.

  As a light source of the photopolymerizable composition comprising these photoinitiating systems, a long wavelength visible light source such as an Ar ion laser (488 nm) or an FD-YAG laser (532 nm), an InGaN-based material is used, and the light source is from 350 nm. A semiconductor laser (violet laser) capable of continuous oscillation in a 450 nm region has been put into practical use. Examples of photoinitiating systems having excellent photosensitivity to these laser beams include Non-Patent Document 1 (Bruce M. Monroe et al., Chemical Review, 93, 435 (1933)) and Non-Patent Document 2 ( RS Davidson, Journal of Photochemistry and biology A: Chemistry, 73, 81 (1993)), Patent Document 1 (Japanese Patent Laid-Open No. 11-84647), Patent Document 2 (Japanese Patent Laid-Open No. 2000-147663), and the like. ing.

  With regard to these CTP plates, it is desired to write at a higher speed in order to increase the productivity of the plate-making process. As a drawing laser, a violet laser that can be miniaturized and can produce an inexpensive plate setter. Is attracting attention. Therefore, for the purpose of drawing with a violet laser and increasing the sensitivity, photoinitiating systems, ethylenically unsaturated compounds, binder resin materials, and combination prescriptions are being investigated. It is difficult to achieve both stability and sufficient sensitivity is not obtained.

  Normally, as the sensitivity is increased, dark polymerization tends to occur, and a residual film is formed over time.

  On the other hand, it shows high sensitivity at first, but it does not cause dark polymerization over time, and the sensitivity may decrease, and when this phenomenon is analyzed in detail, it is a change in the aggregation state of the sensitizing dye. It became clear that The crystallized portion loses its photoinitiating ability and appears as white spots in the image portion.

  It has been desired to develop a plate material that improves such a problem related to aging and exhibits high sensitivity for a long period of time.

Bruce M. Monroe et al., Chemical Review, 1933, 93, 435 R. S. Davidson, Journal of Photochemistry and Biology A: Chemistry, 1993, 73, 81 JP 11-84647 A JP 2000-147663 A

  An object of the present invention is to provide a lithographic printing plate for laser scanning exposure that is compatible with a CTP system excellent in workability and economy, and more specifically, can be drawn with a violet laser, and is sensitized over a long period of time. An object of the present invention is to provide a lithographic printing plate that prevents the change (crystallization) of the aggregation state of the dye and stably exhibits high sensitivity.

As a result of intensive studies to achieve the above object, the present inventors have changed the aggregation state of the sensitizing dye by appropriately selecting the sensitizing dye, ethylenically unsaturated compound and binder resin of the photopolymerization layer. It has become clear that crystallization and low sensitivity can be prevented, and the present invention has been achieved.
That is, the present invention relates to a photopolymerizable lithographic printing plate having at least a photopolymerizable photosensitive layer on a support, a photopolymerizable compound having a photopolymerizable photosensitive layer having at least an ethylenically unsaturated group, and a sensitizing dye. A binder resin, a sensitizing dye having an absorption maximum in the range of 300 to 500 nm, a solubility parameter (SP value) of the sensitizing dye, a polymerizable compound having an ethylenically unsaturated group, and a binder resin The difference (absolute value) from the SP value of the mixture is 8 MPa ^1/2 or less.

  The present invention makes it possible to provide a lithographic printing plate that is stable and sensitive even over a long period of time.

The present invention will be described in detail below.
Although the embodiment of the present invention has a photopolymerizable photosensitive layer on a support, it is preferable to laminate a protective layer on the photopolymerizable photosensitive layer. Moreover, you may provide an intermediate | middle layer between a support body and a photopolymerizable photosensitive layer as needed.

[1] Support The conventionally known support can be used without any particular limitation, but an aluminum support is preferable. Aluminum supports are widely used in lithographic printing plates because they have good dimensional stability, are relatively inexpensive, and can provide a surface with excellent hydrophilicity and strength by surface treatment as required. A composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 can also be applied.

  A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements. Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  In the case of a support having a surface of metal, particularly aluminum, roughening (graining) treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluoride zirconate, phosphate, etc., or anodic oxidation treatment, etc. It is preferable that surface treatment is performed. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. In addition, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in an electrolytic solution such as hydrochloric acid or nitric acid. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used. Further, prior to roughening the aluminum plate, for example, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like is performed in order to remove the rolling oil on the surface, if desired.

  Furthermore, an aluminum plate that has been roughened and then immersed in an aqueous sodium silicate solution can be preferably used. As described in Japanese Examined Patent Publication No. 47-5125, an aluminum plate which has been anodized and then immersed in an aqueous solution of an alkali metal silicate is preferably used. The anodizing treatment is carried out in an electrolytic solution in which an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid or boric acid, or an organic acid such as oxalic acid or sulfamic acid, or a salt solution thereof, or a combination of two or more thereof, is used. This is carried out by passing an electric current using the aluminum plate as an anode. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective.

  Furthermore, a combination of a support with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, JP-A-52-30503, and the above-mentioned anodizing treatment and sodium silicate treatment Surface treatment is also useful. Further, those obtained by performing mechanical surface roughening, chemical etching, electrolytic graining, anodizing treatment, and sodium silicate treatment in this order as disclosed in JP-A-56-28893 are also suitable.

[2] Intermediate layer After the above treatment, a water-soluble resin such as polyvinyl phosphonic acid, a polymer having a sulfonic acid group in the side chain and a copolymer (JP-A-59-101651), as an intermediate layer, Polyacrylic acid, a water-soluble metal salt (for example, zinc borate), a yellow dye, an amine salt, or the like can be provided. Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-7-159983 is covalently used.

Other preferred examples include an undercoat layer having an onium group described in JP-A No. 2003-021908, and a substrate provided with a water-resistant hydrophilic layer as a surface layer on an arbitrary support. Examples of such a surface layer include a layer comprising an inorganic pigment and a binder described in US3055295 and JP-A-56-13168, a hydrophilic swelling layer described in JP-A-9-80744, and JP-A-8-507727. The sol-gel film made of titanium oxide, polyvinyl alcohol, silicic acid or the like described in the above can be raised. These hydrophilic treatments are performed to make the surface of the support hydrophilic, in order to prevent harmful reactions of the photosensitive composition provided thereon, and to improve the adhesion of the photosensitive layer, etc. It is given for.
The coating amount of the intermediate layer, as dry weight, generally 0.5 to 500 mg / m ^2, preferably from 1 to 100 mg / m ^2.

[3] Photopolymerizable photosensitive layer The photosensitive composition for coating the photopolymerizable photosensitive layer (hereinafter also simply referred to as photosensitive layer) of the present invention comprises at least a polymerizable compound having an ethylenically unsaturated group, Contains dyes, radical initiators, binder resins as essential components, and, if necessary, co-sensitizers (compounds that are reduced to generate active radicals, compounds that are oxidized to generate active radicals, chain transfer agents), It can contain a polymerization inhibitor, a colorant, and other additives.

(A) Polymerizable compound having an ethylenically unsaturated group (hereinafter also referred to as an addition polymerizable compound)
The polymerizable compound having an ethylenically unsaturated group of the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, more preferably at least a terminal ethylenically unsaturated bond. It is selected from compounds having one, preferably two or more. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used.

  In addition, unsaturated carboxylic acid ester having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group, amide and monofunctional or polyfunctional isocyanate, addition reaction product of epoxy, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an unsaturated carboxylic acid ester having an electrophilic substituent such as an isocyanato group or an epoxy group, an addition reaction product of an amide with a monofunctional or polyfunctional alcohol, an amine or a thiol, a halogen group, Also suitable are substitution reaction products of unsaturated carboxylic acid esters and amides with monofunctional or polyfunctional alcohols, amines and thiols having a leaving substituent such as a tosyloxy group. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

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 hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  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, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) 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. Examples of other esters include, for example, aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A Those having an aromatic skeleton described in JP-A No. 59-5241 and JP-A-2-226149, those containing an amino group described in JP-A-1-165613, and the like are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  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. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (VI) to a polyisocyanate compound having two or more isocyanate groups. Etc.
_{CH 2 = C (R) COOCH} 2 CH (R ') OH (VI)
(However, R and R ′ represent H or CH _3. )
Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable.

  Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, It is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Examples thereof include polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, and JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 can also be exemplified. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, those introduced as photocurable monomers and oligomers in Journal of Japan Adhesion Association vol. 20, No. 7, pages 300 to 308 (1984) can also be used.

  In addition, α-hetero type monomers having a structure represented by the general formula (I) described in JP-A-2001-92127 can also be suitably used. Specific examples of the α-hetero monomer are shown below.

For these addition-polymerizable compounds, the details of the method of use, such as what type of structure is used, whether it is used alone or in combination, and how much it is added, can be selected according to the performance design of the final photosensitive material. Can be set.
For example, it is selected from the following viewpoints. From the viewpoint of the speed of photosensitivity, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. In addition, when used in a photosensitive layer for a lithographic printing plate, in order to increase the strength of the image area, that is, the cured film, it is preferable to have a trifunctional or higher functional group, and further, a different functional number and a different polymerizable group (for example, acrylic acid). A method of adjusting both photosensitivity and strength is also effective by using a combination of an ester, a methacrylic ester, a styrene compound, or a vinyl ether compound. A compound having a large molecular weight or a compound having a high hydrophobicity is not preferable in terms of development speed and precipitation in a developing solution, although it is excellent in photosensitive speed and film strength. In addition, the selection of the addition polymerization compound is also required for the compatibility and dispersibility with other components in the photosensitive layer (for example, the binder resin described later, the photopolymerization initiator (system) described above, the colorant described later, etc.). -The usage method is an important factor. For example, compatibility may be improved by using a low-purity compound or using two or more kinds in combination.

In addition, a specific structure may be selected for the purpose of improving the adhesion of the support, the protective layer and the like. As for the compounding ratio of the addition polymerizable compound in the photosensitive layer, a larger amount is advantageous in terms of sensitivity. However, when the amount is too large, undesirable phase separation occurs or the production process due to the adhesiveness of the photosensitive layer occurs. Problems such as transfer of photosensitive material components (manufacturing defects due to adhesion) and precipitation from the developer may occur.
From these viewpoints, the addition amount of the addition polymerizable compound is generally 5 to 80% by mass, preferably 25 to 75% by mass with respect to the total solid content of the composition. These may be used alone or in combination of two or more.
In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

(B) Binder resin The binder resin preferably contains a linear organic polymer. The linear organic polymer is not particularly limited, but is preferably selected from water or weak alkaline water soluble or swellable linear organic polymer capable of water development or weak alkaline water development. .
The linear organic high molecular polymer is selected and used not only as a film-forming agent for the composition but also according to its use as water, weak alkaline water or an organic solvent developer. For example, when a water-soluble organic polymer is used, water development is possible. Examples of such linear organic high molecular polymers include addition polymers having a carboxylic acid group in the side chain, such as JP 59-44615, JP-B 54-34327, JP-B 58-12777, and JP-B. 54-25957, JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Examples include acid copolymers, crotonic acid copolymers, maleic acid copolymers, and partially esterified maleic acid copolymers. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful.

  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] are preferred because they are excellent in the balance of film strength, sensitivity and developability.

  In addition, Japanese Patent Publication No. 7-2004, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Laid-Open No. 63-287944, Japanese Patent Laid-Open No. 63-287947, Japanese Patent Laid-Open No. The urethane-based binder polymer containing an acid group described in the specifications of No. 271741 and Japanese Patent Application No. 10-116232 is very excellent in strength, and is advantageous in terms of printing durability and low exposure suitability. is there. A binder having an amide group described in JP-A No. 11-171907 is suitable because it has both excellent developability and film strength.

In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful.
The binder resin can be mixed in an arbitrary amount. 90 mass% or less is preferable with respect to the total solid of a photosensitive composition at points, such as image strength, and 30-85 mass% is more preferable.
The polymerizable compound having an ethylenically unsaturated double bond and the binder resin are preferably in the range of 1/9 to 7/3 by mass ratio.

In a preferred embodiment, a binder resin that is substantially insoluble in water and soluble in alkali is used. By doing so, an organic solvent that is not environmentally preferable is not used as the developer, or the amount can be limited to a very small amount.
In such a method of use, the acid value of the binder resin (the acid content per gram of the polymer expressed as a chemical equivalent number) and the molecular weight are appropriately selected from the viewpoints of image strength and developability.
The acid value of the binder resin is preferably 0.4 to 3.0 meq / g, more preferably 0.6 to 2.0 meq / g.
The molecular weight of the binder resin is preferably 3000 to 500,000, more preferably 10,000 to 300,000.

(C) Sensitizing dye The sensitizing dye used in the present invention is a dye having a maximum absorption at 300 nm to 500 nm. The dye that has absorbed light and is in an excited state generates radicals with high efficiency by interaction with a radical initiator described later.

  Specifically, a dye having an oxazoline acidic nucleus described in JP-B-61-9621, a dye having an oxazolone acidic nucleus described in JP-A-8-272096, and a heterocyclic acidic nucleus described in JP-A-10-101719. A dye, a naphthofuranone dye described in JP-A No. 2000-206690, a carbonyl dye described in JP-A No. 11-212549, an oxazolidinone-containing dye described in JP-A No. 2001-100272, and a bismerocyanine described in JP-A No. 2000-309724 Dyes, carbazolyl styryl dyes described in JP-A No. 2001-42524, pyrrolopyrrole dyes described in JP-A No. 2002-351065, bisbenzothiazole dyes described in JP-A No. 2002-351072, and Japanese Patent Application No. 2001-159059 Stilbene dyes described in Japanese Patent Application No. 2002-0 Diarylaminostyryl dyes described in No. 1723, dyes described in Japanese Patent Application Nos. 2001-401891, JP-A 2003-021895, JP-A 2003-021894, JP-A 2003-021901, and the like are used. The

The photosensitive layer of the present invention is required to satisfy the following formula for the solubility parameter (SP value) of the sensitizing dye.
| SP value of sensitizing dye-SP value of a mixture of a polymerizable compound having an ethylenically unsaturated group and a binder resin | ≦ 8 MPa ^1/2
Preferably, the left side is 5 MPa ^1/2 or less.

The SP value is an accumulated value using the theoretical formula proposed by Toshinao Okitsu (Journal of Adhesion Society of Japan, Vol. 29, No. 6 (1993), pages 249 to 259). The weighted average value was adopted according to the molar ratio.
Further, the SP value of the mixture of the polymerizable compound having an ethylenically unsaturated group and the binder resin was obtained by weighted averaging with the mass ratio.

By increasing the compatibility of the sensitizing dye with the other main components of the photosensitive layer, it is possible to reduce the fluctuation of the aggregation state of the sensitizing dye over time, preventing crystallization and ensuring stable sensitivity. It becomes possible.
The sensitizing dye that satisfies the SP value requirement may be used alone or in combination of two or more.
The addition amount of the sensitizing dye that satisfies the SP value requirement is generally 0.1 to 30% by mass, preferably, based on the total solid content of the photosensitive composition for constituting the photosensitive layer, preferably 0.5 to 10% by mass.

  The sensitizing dye preferably has a melting point of less than 140 ° C, more preferably 10 to 130 ° C.

Moreover, it is preferable to use 2 or more types of sensitizing dyes together. That is, two or more sensitizing dyes satisfying the SP value requirement may be used, or a sensitizing dye satisfying the SP value requirement and another sensitizing dye not satisfying the SP value requirement may be used in combination.
It is preferable to mix in the range of 1:10 to 100: 1 as a mass ratio of one kind of sensitizing dye that satisfies the SP value requirement to the other sensitizing dye.
As the other sensitizing dye, a sensitizing dye having a structure similar to that of one sensitizing dye satisfying the SP value requirement is preferable.

  As the most preferable dye as the sensitizing dye in the present invention, among the diarylaminostyryl dyes represented by the following general formula (1) described in Japanese Patent Application No. 2002-021723, those satisfying the conditions of the melting point and the SP value are raised. I can do it. Among these dyes, many of the dyes satisfying the melting point and SP value have substituents that lower the melting point and reduce the SP value of long-chain alkyl, alkyloxy groups and the like as substituents.

(R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or a monovalent nonmetallic atomic group. R ⁵ represents R ¹ , R ² , R ³ , R ^4. Ar ¹ and Ar ² each independently represents an aromatic group or an aromatic heterocyclic residue which may have a substituent, respectively, to form an aliphatic or aromatic ring. G ¹ and G ² each independently represents a monovalent nonmetallic atomic group.)

The general formula (1) will be described in detail. R ¹ , R ² , R ³ , R ⁴ and R ⁵ 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 unsubstituted aryl group, substituted or unsubstituted aromatic heterocyclic residue, substituted or unsubstituted alkoxy group, substituted or unsubstituted amino group, substituted or unsubstituted alkylthio group, hydroxy group, halogen atom Represents.

Preferable examples of R ¹ , R ² , R ³ , R ⁴ and R ⁵ 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 a hydrogen atom is used. Preferred examples include halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups, and alkoxy groups. , 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 ,

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 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 Ruureido 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,

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-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 conjugate base group (hereinafter referred to as “phosphonate group”), dialkyl phosphono 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), a dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), a diarylphosphonooxy group (—OPO ₃ (aryl) ₂ ), an alkylarylphosphonooxy group (—OPO ₃ (alkyl) (aryl) )), -Alkyl phosphonooxy group (-OPO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (aryl)) and its conjugate Examples include a base group (hereinafter referred to as an arylphosphonatooxy 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, cyanophene Group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl phenyl group, and a phosphonophenyl phenyl group.

  As the heteroaryl group, a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used. Examples of particularly preferred heteroaryl groups include 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, cinolin, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenazazine, phenoxazine, furazane, phenoxazine, etc. These further may be benzo-fused or may have a substituent.

  Examples of alkenyl groups include vinyl, 1-propenyl, 1-butenyl, cinnamyl, 2-chloro-1-ethenyl, etc. Examples of alkynyl include ethynyl, 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.

Although the substituent of the substituted alkyl group preferable as R < ¹ >, R < ² >, R < ³ >, R < ⁴ >, R < ⁵ > obtained by combining this substituent and an alkylene group is arbitrary, As a specific example of a preferable substituted alkyl group, Chloromethyl, bromomethyl, 2-chloroethyl, trifluoromethyl, methoxymethyl, methoxyethoxyethyl, allyloxymethyl, phenoxymethyl, methylthiomethyl, tolylthiomethyl, ethylaminoethyl, 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, allyl Oxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl-N- (sulfo) Phenyl) 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, methylphosphonatobutyl group , Tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonateoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methyl Benzyl 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. be able to.

Specific examples of preferred substituted amino groups as R ¹ , R ² , R ³ , R ⁴ and R ⁵ include N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diaryl. Amino group, N-alkyl-N-arylamino 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, N-alkylamino group, N, N-dialkylamino group, acylamino group, N-alkylacylamino group, N-arylacylamino group Etc.

Specific examples of preferable aryl groups as R ¹ , R ² , R ³ , R ⁴ , and R ⁵ include those in which 1 to 3 benzene rings form a condensed ring, and a benzene ring and a 5-membered unsaturated ring are condensed. Examples thereof include a ring-forming group, and specific examples thereof 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 A naphthyl group is more preferable.

Specific examples of preferable substituted aryl groups as R ¹ , R ² , R ³ , R ⁴ and R ⁵ include monovalent nonmetallic atomic groups excluding hydrogen as substituents on the ring-forming carbon atoms of the aforementioned aryl groups. What has is used. 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, diphenylphosphonophenyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group , Tolylphosphonate phenyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallylphenyl group, 2-methylpropenylphenyl group, 2-propynylphenyl group, 2-butynylphenyl group, 3- List butynylphenyl groups, etc. It can be.

Specific examples of preferable aromatic heterocyclic residues as R ¹ , R ² , R ³ , R ⁴ and R ⁵ include 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, cinolin, pteridine, carbazole, carboline, phenanthrine, acridine, Examples include perimidine, phenanthroline, phthalazine, phenazazine, phenoxazine, furazane, phenoxazine, and the like. These may be further benzo-fused and may have a substituent.

Examples of the substituted or unsubstituted aromatic group or aromatic heterocyclic residue in Ar ¹ and Ar ² include the same as those described in detail for R ^{1 to} R ⁵ , but the crystallinity of the compound increases. Aromatic heterocyclic residues are more preferred.
Next, examples of G ¹ and G ² in the general formula (1) include the examples described in R ^{1 to} R ⁵ , and the following specific examples are particularly preferable. For example, halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkyl Amino 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, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido , N'- alkylureido group, N ', N'- dialkyl ureido group, N'- arylureido group, N', N 'one diaryl ureido group, N'- alkyl -N
'-Aryl ureido group, N-alkyl ureido group, N-aryl ureido 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-arylureido 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-NT arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, a70
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 monoalkylsulfamoyl group, N, N -Dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N
A monoalkyl-N-arylsulfamoyl group, a phosphono group (—PO ₃ H ₂ ) and a conjugate base group thereof (hereinafter referred to as a phosphonate group), a dialkylphosphono group (—PO;
Alkyl) ₂ ), diaryl phosphino group (—PO ₃ (aryl) ₂ ), alkyl phos phono group (—PO ₃ (alkyl) ar aryl)), monoalkyl phosphino group (—PO ₃ H (al
kyl)) and conjugated base groups thereof (hereinafter referred to as alkyl phosphonate groups), monoaryl phosphono groups (—PO ₃ H (aryl)) and conjugated base groups thereof (hereinafter referred to as aryl phosphonate groups), phosphonooxy Group (-OPO ₃ H ₂ ) and its conjugate base group (
Hereafter referred to as phosphonatooxy group), dialkylphosphonooxy group (-OPO ₃
(Alkyl) ₂ ), diaryl phosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylaryl phosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (—OPO ₃ H (Alkyl)) and its conjugate base group (hereinafter referred to as alkyl phosphonatooxy group), monoaryl phosphonooxy group (—OPO ₃ H (aryl
)) And conjugated base groups thereof (hereinafter referred to as aryl phosphonatooxy groups), cyano groups, nitro groups, substituted or unsubstituted aryl groups, heteroaryl groups, alkenyl groups, and alkynyl groups.

  Although the preferable specific example of a compound represented by General formula (1) below is shown, this invention is not limited to this. In addition, the isomer due to the double bond connecting the acidic nucleus and the triphenylamine skeleton is not clear, and the present invention is not limited to either isomer.

(C) Radical initiator As the radical initiator used in the present invention, a compound capable of generating a radical capable of initiating polymerization can be appropriately selected and used by interaction with the above-described sensitizing dye.
For example, as described in Chapter 5 of “Light Sensitive Systems” by J. Kosar, a carbonyl compound, an organic sulfur compound, a persulfide, a redox compound, an azo compound, a diazo compound, a halogen compound, Examples thereof include photoreducible dyes, and the compounds disclosed in British Patent 1,459,563 are also preferable.

  Specifically, the following examples can be given, but the invention is not limited thereto. Benzoin derivatives such as benzoin methyl ether, benzoin-i-propyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4′-bis (Dimethylamino) benzophenone derivatives such as benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-i-propylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; N-methylacridone and N-butylacrylic Acridone derivatives such as dong; α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, Japanese Patent Publication Nos. 59-1281, 61-9621, and JP 60-60104 The triazine derivatives described above; organic peroxides described in JP-A-59-1504 and JP-A-61-243807; JP-B-43-23684, JP-A-44-6413, JP-A-44-6413, and JP-A-47-1604 And diazonium compounds described in US Pat. No. 3,567,453; organic azide compounds described in US Pat. Nos. 2,848,328, 2,852,379 and 2,940,853; Various onium compounds described in JP-A-55-39162, JP-A-59-14023 and “Macromolecules”, Vol. 10, page 1307 (1977); azo compounds described in JP-A-59-142205; JP-A-1-54440, European Patent Nos. 109,851, 126,712 and "Journal Of Imaging Science (J. Imag. Sci.), 30, 174 (1986); (oxo) sulfonium organoboron complexes described in JP-A-5-213861 and 5-255347 Titanocenes described in JP-A-59-152396 and JP-A-61-151197; "Coordination Chemistry Review", 84, 85-277 (1988) and JP-A-2- Transition metal complexes containing a transition metal such as ruthenium described in No. 182701, 2,4,5-triarylimidazole dimer described in JP-A-3-209477, carbon tetrabromide, JP-A-59-107344 Halogenated organic compounds described in the above item.

  Of these, preferred are titanocenes. Specific examples of titanocenes include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3,4. , 5,6-pentafluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophenyl, 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- Difluorophen-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- (pyridin-1-yl) phenyl) titanium (IRUGACURE784: manufactured by Ciba Specialty Chemicals) and the like, but are not limited thereto.

  Regarding the radical initiator contained in the photosensitive composition of the present invention, as in the case of the sensitizing dye, when the photosensitive layer of the lithographic printing plate precursor is used, various chemical modifications for improving its properties are performed. It is also possible to do this. For example, bonding with sensitizing dyes, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents to suppress crystal precipitation, introduction of substituents to improve adhesion A method such as polymerization can be used.

The usage of these radical initiators can be arbitrarily set as appropriate depending on the performance design of the light-sensitive material, as in the case of the above-mentioned addition polymerizable compound and sensitizing dye.
For example, the sensitivity can be further increased by using two or more kinds in combination.
A larger amount of radical initiator such as titanocene compound is usually advantageous in terms of photosensitivity, and is usually 0.5 to 80 parts by mass with respect to 100 parts by mass of components (total solid content) constituting the photosensitive layer. Preferably sufficient photosensitivity is obtained by using in 1-50 mass parts.
On the other hand, for use in white lighting such as yellow, it is preferable that the amount of titanocene used is small from the viewpoint of fogging by light near 500 nm, but the amount of titanocene used is 6 in combination with the above-mentioned sensitizing dye. Sufficient photosensitivity can be obtained even if it is lowered to not more than parts by mass, further not more than 1.9 parts by mass, and further not more than 1.4 parts by mass.

  In order to use the photosensitive composition of the present invention as a photosensitive layer of a photopolymerization type lithographic printing plate, other components suitable for its use, production method and the like can be added as appropriate. Hereinafter, preferred additives will be exemplified.

(D1) Co-sensitizer The sensitivity of the photosensitive layer can be further improved by using a certain additive (hereinafter referred to as a co-sensitizer). These mechanisms of action are not clear, but many are thought to be based on the following chemical processes.
That is, a photoreaction initiated by light absorption of the above-described photopolymerization initiation system, and various intermediate active species (radicals, peroxides, oxidizing agents, reducing agents, etc.) generated in the course of the subsequent addition polymerization reaction, It is presumed that the co-sensitizer reacts to generate a new active radical.
The co-sensitizers are roughly classified into the following (a) to (c), but there are many cases where there is no general knowledge as to which of the individual compounds belongs.
(A) a compound that can be reduced to produce an active radical (b) a compound that can be oxidized to produce an active radical (c) reacts with a less active radical and converts to a more active radical or chain transfer Compounds acting as agents

(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that an active radical is generated by reductive cleavage of the carbon-halogen bond. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.

Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that the oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.

  Ferrocene and iron arene complexes: An active radical can be reductively generated.

(B) Compound which is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.

  Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines, and the like.

  Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.

  α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopronone-1 and these and a hydroxylamine were reacted, and then N—OH was etherified. Oxime ethers can be listed.

  Sulfinic acid salts: An active radical can be reductively generated. Specific examples include sodium arylsulfinate.

  (C) Compounds that react with radicals to convert into highly active radicals or act as chain transfer agents: For example, a group of compounds having SH, PH, SiH, GeH in the molecule is used. These can generate hydrogen by donating hydrogen to a low-activity radical species to generate radicals, or after being oxidized and deprotonated. Specifically, 2-mercaptobenzimidazoles etc. are mentioned, for example.

  More specific examples of these co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity. Some examples are shown below, but the present invention is not limited thereto.

These co-sensitizers can also be subjected to various chemical modifications for improving the characteristics of the photosensitive layer as in the case of the above sensitizing dye. For example, bonds with sensitizing dyes, titanocene, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, improved compatibility, introduction of substituents for suppressing crystal precipitation, substituents for improving adhesion Methods such as introduction and polymerization can be used. These co-sensitizers can be used alone or in combination of two or more.
The amount of the co-sensitizer used is usually 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 3 to 50 parts per 100 parts by weight of the polymerizable compound having an ethylenically unsaturated double bond. Part by mass.

(D2) Polymerization inhibitor In the photosensitive composition of the present invention, a small amount of polymerization is used to prevent unnecessary polymerization of a polymerizable compound having an ethylenically unsaturated double bond during its production or storage. It is desirable to add an inhibitor.
As polymerization inhibitors, hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like.
The addition amount of the polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the total solid content of the composition.

  Further, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition due to oxygen, and may be unevenly distributed on the surface of the photosensitive layer in the course of drying after coating. The amount of the higher fatty acid derivative added is preferably about 0.5% by mass to about 10% by mass with respect to the total solid content of the composition.

(D3) Colorant, etc. A dye or pigment may be added for the purpose of coloring the photosensitive layer. As a result, it is possible to improve the so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring machine as a lithographic printing plate precursor. As the colorant, many dyes cause a decrease in the sensitivity of the photopolymerization type photosensitive layer. Therefore, it is particularly preferable to use a pigment as the colorant. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, 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 based on the total solid content of the composition.

(D4) Other Additives Known additions such as inorganic fillers, other plasticizers, and oil sensitizers that can improve the ink inking property on the surface of the photosensitive layer in order to improve the physical properties of the cured film of the photosensitive layer An agent may be added. Examples of plasticizers include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin. 10 mass% or less can be added with respect to the total mass of the polymerizable compound which has an ionic unsaturated double bond, and binder resin.

  Further, for the purpose of improving the film strength (printing durability) of the photosensitive layer, a UV initiator, a thermal crosslinking agent, or the like can be added to enhance the effect of heating and exposure after development. In addition, it is possible to provide an additive and an intermediate layer for improving the adhesion between the photosensitive layer and the support and for improving the development removability of the unexposed photosensitive layer. For example, by adding or undercoating a compound having a relatively strong interaction with a substrate described later, such as a compound having a diazonium structure or a phosphone compound, adhesion can be improved and printing durability can be increased. By adding or undercoating with a hydrophilic polymer such as acrylic acid or polysulfonic acid, the developability of the non-image area is improved, and the stain resistance can be improved.

  When the photosensitive composition of the present invention is applied as a photosensitive layer on a support, it is dissolved in various organic solvents and used. Solvents 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, Ethylene 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. And the density | concentration of the solid content in a coating solution is 2-50 mass% normally.

The coating amount of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the developability, the strength of the exposed film, and the printing durability, and is preferably selected as appropriate according to the application. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. As the lithographic printing plate for scanning exposure which is the main purpose of use of the photosensitive composition of the present invention, the coating amount is generally in the range of about 0.1 g / m ² to about 10 g / m ² in terms of the mass after drying. And more preferably 0.5 to 5 g / m ² .

[4] Protective layer In the lithographic printing plate for scanning exposure, which is a desirable use mode of the photosensitive composition of the present invention, the exposure is usually carried out in the air. Therefore, on the layer made of the photosensitive composition, Furthermore, it is preferable to provide a protective layer. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer, and enables exposure in the atmosphere. To do. Therefore, the properties desired for such a protective layer are low permeability of low-molecular compounds such as oxygen, and further, transmission of light used for exposure is not substantially inhibited, and adhesion to the photosensitive layer is excellent. And it is desirable that it can be easily removed in the development process after exposure. Such a device relating to the protective layer has been conventionally devised, which is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729.

  On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in US Pat. Nos. 292,501 and 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing by mass% and laminating on a polymerized layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and JP-A-55-49729.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (such as a water-soluble dye) that excels in light transmission from 350 nm to 550 nm used for exposure and can efficiently absorb light of 550 nm or more, it is suitable for safe light without causing a decrease in sensitivity. Can be further enhanced.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, Water-soluble polymers such as acrylic acid are known, but among these, the use of polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100% and a molecular weight 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 and the like.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure. In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic polymer layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization.

The coating amount of the protective layer is a dry weight, generally 0.1 to 10 g / m ^2, preferably from 0.5 to 5 g / m ^2.

  In addition, as a plate-making process of a lithographic printing plate from a lithographic printing plate precursor using the photosensitive composition of the present invention as a photosensitive layer, the entire surface can be used before exposure, during exposure, and from exposure to development as necessary. May be heated. By such heating, the 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 subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as covering up to the non-image area occur. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

  As a method for exposing a lithographic printing plate precursor using the photosensitive composition of the present invention for a photosensitive layer, a known method can be used without limitation. Desirably, the wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN-based semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. Further, the photosensitive layer component can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component, and the lithographic printing plate precursor having such a configuration is used in a printing machine. After loading on top, exposure-development can be performed on the machine.

Further, as other exposure light rays for the photopolymerizable composition according to the present invention, ultrahigh pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet lasers. A lamp, a fluorescent lamp, a tungsten lamp, sunlight, etc. can also be used. As available laser light sources of 350 nm to 450 nm, the following can be used. As a gas laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser as Nd: YAG (YVO4) and SHG crystal x 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), KNbO ₃ ring resonator (430 nm, 30 mW) as a semiconductor laser system, Combination of waveguide type wavelength conversion element and AlGaAs / InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide type wavelength conversion element, AlGaInP and AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 10 mW) mW), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW) and other pulse lasers such as N2 laser (337 nm, pulse 0.1 to 10 mJ), XeF (351 nm, pulse 10 to 250 mJ), particularly AlGaInN semiconductor laser (commercially available InGaN) System semiconductor lasers 400 to 410 nm, 5 to 30 mW) are preferable in terms of wavelength characteristics and cost.

  Further, as the lithographic printing plate exposure apparatus of the scanning exposure method, there are an inner drum method, an outer drum method, and a flat bed method as an exposure mechanism, and a light source that can continuously oscillate among the light sources can be preferably used. . Practically, the following exposure apparatus is particularly preferable in terms of the relationship between the photosensitive material sensitivity and the plate making time.

・ Single beam to triple beam exposure equipment that uses one or more gas lasers or solid laser light sources so that the internal drum system produces a semiconductor laser with a total output of 20 mW or more. ・ The total output of the flat bed system is 20 mW or more. , Multi-beam (1 to 10) exposure equipment using one or more semiconductor lasers, gas lasers or solid-state lasers ・ 1 semiconductor laser, gas laser or solid-state laser is used so that the total output is 20 mW or more by the external drum system. Multi-beam (1 to 9) exposure equipment using more than one ・ Multi-beam (10 or more) exposure equipment using one or more semiconductor lasers or solid-state lasers so that the total output is 20 mW or more with the external drum system In the laser direct drawing type lithographic printing plate as described above, in general, the photosensitive material sensitivity X ( J / cm ² ), exposure area S (cm ² ) of the light-sensitive material, power q (W) of one laser light source, n number of lasers, and total exposure time t (s), the formula (eq 1) is established. To do.

X · S = n · q · t-(eq 1)
i) In the case of the internal drum (single beam) system, the laser rotation speed f (radians / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dots / cm), and the total exposure time t (s) In general, equation (eq 2) holds.

f.Z.t = Lx-(eq 2)
ii) External drum (multi-beam) system Drum rotation speed F (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), number of beams In general, the equation (eq 3) is established during (n).

F.Z.n.t = Lx-(eq 3)
iii) In the case of the flat head (multi-beam) system, the rotational speed H (radian / s) of the polygon mirror, the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dot / cm), the total exposure time t (s), Equation (eq 4) is generally established between the number of beams (n).

F.Z.n.t = Lx-(eq 4)
Resolution (2560 dpi) required for an actual printing plate, plate size (A1 / B1, sub-scanning length 42 inch), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the photosensitive composition of the present invention (photosensitive wavelength, By substituting (sensitivity: about 0.1 mJ / cm ² ) into the above formula, the photosensitive material using the photosensitive composition of the present invention can be combined with a multi-beam exposure method using a laser having a total output of 20 mW or more. It can be seen that it is particularly preferable. Further, by combining operability, cost, etc., a combination with an external drum type semiconductor laser multi-beam (10 or more) exposure apparatus is most preferable.

After image exposure, an unexposed portion of the photosensitive layer is removed with a developer to obtain an image.
Preferred developers include those described in JP-B-57-7427, such as sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium triphosphate. Of inorganic alkaline agents such as dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia etc. and organic alkaline agents such as monoethanolamine or diethanolamine An aqueous solution is suitable. It is added so that the concentration of such an alkaline solution is 0.1 to 10% by mass, preferably 0.5 to 5% by mass.

  Such an alkaline aqueous solution may contain a small amount of a surfactant, an organic solvent such as benzyl alcohol, 2-phenoxyethanol, and 2-butoxyethanol as necessary. Examples thereof include those described in US Pat. Nos. 3,375,171 and 3,615,480. Further, the developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, and 56-42860 are also excellent.

  Moreover, as a use of the photosensitive composition by this invention, it can apply without a restriction | limiting to what is widely known as a use of photocurable resin besides the planographic printing plate for scanning exposure. For example, a highly sensitive optical modeling material can be obtained by applying to a liquid photopolymerizable composition used in combination with a cationic polymerizable compound as necessary. Further, a hologram material can be obtained by utilizing a change in refractive index accompanying photopolymerization. It can be applied to various transfer materials (peeling sensitive material, toner developing sensitive material, etc.) by utilizing the change in surface adhesiveness accompanying photopolymerization. It can also be applied to photocuring of microcapsules. It can also be applied to the production of electronic materials such as photoresists, and photocurable resin materials such as inks, paints, and adhesives.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

[Examples 1 to 3, Comparative Examples 1 and 2]
An aluminum plate of material 1S having a thickness of 0.3 mm was used with a No. 8 nylon brush and an aqueous suspension of 800 mesh Pamiston, the surface of which was grained, and then thoroughly washed with water. After etching by immersing in 10% sodium hydroxide at 70 ° C. for 60 seconds, washed with running water, neutralized and washed 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 quantity of 300 coulomb / dm ² using a sinusoidal alternating current under the condition of V _A = 12.7V. When the surface roughness was measured, it was 0.45 μm (Ra indication) (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 μm). 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 2.7 g / m ² .

(Formation of intermediate layer)
On the aluminum plate thus treated, methyl methacrylate / ethyl acrylate / 2-acrylamido-2-methylpropane sodium sulfonate copolymer (60/25/15 molar ratio, molecular weight Mn = 30,000) A solution (priming solution) dissolved in methanol = 5 g / 95 g was applied and dried at 80 ° C. for 30 seconds. The thickness of this intermediate layer was 3 mg / m ² .

[Formation of back coat layer]
The following sol-gel reaction liquid was applied to the back surface of the substrate thus treated with a bar coater, dried at 100 ° C. for 1 minute, and a support provided with a backcoat layer having a coating amount after drying of 70 mg / m ^2. It was created.

(Sol-gel reaction solution)
Tetraethylsilicate 50 parts by weight Water 20 parts by weight Methanol 15 parts by weight Phosphoric acid 0.05 parts by weight

  When the above components were mixed and stirred, heat generation started in about 5 minutes. After reacting for 60 minutes, a backcoat coating solution was prepared by adding the following solution.

Pyrogallol formaldehyde condensation resin (molecular weight 2000) 4 parts by weight Dimethyl phthalate 5 parts by weight Fluorosurfactant 0.7 parts by weight (N-butylperfluorooctanesulfonamidoethyl acrylate / polyoxyethylene acrylate copolymer: molecular weight 20,000)
Methanol silica sol (manufactured by Nissan Chemical Industries, Ltd., methanol 30% by mass)
50 parts by mass Methanol 800 parts by mass

(Preparation of photosensitive layer)
The photopolymerizable composition having the following composition was applied to the intermediate layer side of the aluminum plate thus treated so that the dry coating amount was 1.0 g / m ² and dried at 80 ° C. for 2 minutes to form a photosensitive layer. Formed.

Pentaerythritol tetraacrylate 1.5g
Allyl methacrylate / methacrylic acid /
N-isopropylacrylamide copolymer 2.0g
(Molar ratio of copolymerization 67/13/20)
Photopolymerization initiation system Sensitizing dye (described in Table 7) 0.1 g
Titanocene compound 0.1g

  Co-sensitizer 0.3g

Fluorine-based nonionic surfactant (F-177P) 0.02 g
Thermal polymerization inhibitor N-nitrosophenyl hydroxyl 0.01 g
Amine aluminum salt Pigment dispersion 2.0g
Composition of pigment dispersion Composition: Pigment Blue 15: 6 15 parts by mass
Allyl methacrylate / methacrylic acid copolymer 20 parts by mass
(Copolymerization molar ratio 83/17)
15 parts by mass of cyclohexanone
20 parts by mass of methoxypropyl acetate
Propylene glycol monomethyl ether 40 parts by weight Methyl ethyl ketone 20.0 g
Propylene glycol monomethyl ether 20.0g

(Preparation of protective layer)
An aqueous solution having the following composition was applied onto the photosensitive layer so that the dry coating mass was 2 g / m ² and dried at 100 ° C. for 2 minutes.
Pure water 1500g
Polyvinyl alcohol 90g
(Saponification degree 98 mol%, polymerization degree 550)
Polyvinylpyrrolidone 5g
Poly (vinyl acetate / vinyl pyrrolidone) 5g

  In order to grasp the sensitivity of the printing plate over time, crystallization, etc., a plate was prepared that was left for 5 days under forced aging conditions (50 ° C., 80% RH).

<Evaluation of sensitivity and crystallization>
A Fuji step guide manufactured by Fuji Photo Film Co., Ltd. (gray scale whose transmission optical density changes discontinuously at ΔD = 0.15) was brought into close contact with the lithographic printing plate precursor thus obtained. Using a xenon lamp through a filter (Kenko BP-40), exposure was performed so as to obtain a known exposure energy. As an optical filter, Kenko BP-40 capable of exposure with monochromatic light of 400 nm was used for the purpose of estimating the suitability of exposure to a short wave semiconductor laser. Thereafter, the film was dipped in a developer solution having the following composition at pH 12 for 10 seconds at 25 ° C., developed, and the sensitivity (clear sensitivity) was calculated from the maximum number of steps at which the image was completely removed (Table 7 below). Here, the clear sensitivity represents the minimum energy required for image formation, and the lower this value, the higher the sensitivity.

(Developer composition)
Potassium hydroxide 0.2 parts by weight Compound of formula 1 below 5.0 parts by weight Kirest 400 (chelating agent) 0.1 parts by weight Water 94.8 parts by weight

  Further, the evaluation of the crystallization of the sensitizing dye in the photosensitive layer is carried out by visually and x-exposing this state because when the sensitizing dye is crystallized, spotted or needle-like white spots are generated in the processed exposed portion. Observation and judgment were made with a 50-fold magnifier.

<Melting point of sensitizing dye, SP value>
The melting point was determined by the usual method of checking the melting point while heating the crystal in a capillary tube and calculating the SP value according to the above-mentioned Okitsu equation. The results are shown in Table 7.

<Examples 4 to 6, Comparative Examples 3 and 4>
Except that the undercoating liquid of Example 1 and the photopolymerization composition for coating a photosensitive layer were changed to the liquids shown below, the same operations as in Example 1 were performed, and the sensitivity and crystallization of the sensitizing dye in the photosensitive layer were performed. Investigated about. The results are shown in Table 7.

<Undercoat liquid>
The following components were mixed and stirred. After about 5 minutes, heat generation was observed, and after 60 minutes of reaction, the contents were transferred to another container, and further 30,000 parts by mass of methanol was added to make liquid composition 2.

Unichemical Co., Ltd. Phosmer PE 20 parts by mass Methanol 130 parts by mass Water 20 parts by mass Paratoluenesulfonic acid 5 parts by mass Tetraethoxysilane 50 parts by mass 3-Methacryloxypropyltriethoxysilane 50 parts by mass

<Coating solution for photosensitive layer>
Ethylenically unsaturated bond-containing compound (A1) 1.5 parts by mass Linear organic polymer (polymer binder) (B1) 2.0 parts by mass Photopolymerization initiation system Sensitizing dye (described in Table 7) 0 .1g
Titanocene compound 0.2g

  Co-sensitizer 0.3g

ε-phthalocyanine (F1) dispersion 0.02 parts by mass Dispersion medium: methallyl methacrylate / methacrylic acid = 8/2 (molecular weight 50,000)
0.03 parts by mass of fluorine-based nonionic surfactant Megafac F177 (Dainippon Ink Chemical Co., Ltd.)
Methyl ethyl ketone 9.0 parts by mass Propylene glycol monomethyl ether acetate 7.5 parts by mass Toluene 11.0 parts by mass

<Examples 7 and 8>
Except for changing the sensitizing dye of Example 1 to the dye mixture system shown in Table 7, the same operation was repeated. The results are shown in Table 7.

<Examples 9 and 10>
Except that the sensitizing dye of Example 4 was changed to the dye mixing system shown in Table 7, the same operation was repeated. The results are shown in Table 7.
In Examples 1 to 10 in Table 7, the sensitivity fluctuation before and after forced aging was small, and it was confirmed that no crystallization was observed in the photosensitive layer even after aging and the sensitivity was stably shown. On the other hand, in Comparative Examples 1 to 4, the sensitizing dye was crystallized in the photosensitive layer after the lapse of time, and the phenomenon of sensitivity reduction was observed.

Example 11
An aluminum plate (material: JIS A 1050) with a thickness of 0.3 mm is etched for 10 seconds at caustic soda 30 g / l, aluminum ion concentration 10 g / l, liquid temperature 60 ° C., washed with running water, and 12 g / l nitric acid. After washing with water, it was washed with water. Using an alternating waveform current of a sine wave of 50 Hz, the electrolytic surface is roughened at a hydrochloric acid concentration of 15 g / l, an aluminum ion concentration of 10 g / l, a liquid temperature of 30 ° C., a current density of 16 A / dm ² , and an electric quantity of 400 c / dm ^2. Treated and washed with water. Next, etching is performed for 10 seconds at a caustic soda of 36 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 35 ° C., washed with running water, and then desmutted for 10 seconds in a sulfuric acid aqueous solution having a sulfuric acid concentration of 15 wt% and a liquid temperature of 30 ° C. And washed with water. Furthermore, anodization was performed in a 10% aqueous sulfuric acid solution at a liquid temperature of 20 ° C. under a current density of 6 A / dm ^{2 so that} the amount of the anodized film was equivalent to ^2.5 g / m ² . When the surface roughness was measured, it was Ra = 0.44 μm.

  In order to ascertain the sensitivity of the printing plate over time, crystallization, etc., by applying the same intermediate layer, photosensitive layer, and protective layer to this aluminum support as in Example 9, and drying to create a printing plate. It was left for 3 days under forced aging conditions (60 ° C., 50% RH).

<Evaluation of sensitivity and crystallization>
Evaluation was conducted in the same manner as in Example 9 except that a developer having the following formulation having a pH of 12.3 was used. The results are shown in Table 7.
Developer formulation 1K-Potassium silicate 2.5g
Potassium hydroxide 0.08g
Polyethylene naphthyl ether 5.0 g
Kirest 400 (chelating agent) 0.1g
92.32 g of water

The sensitizing dyes (1) to (6) in Table 7 are as follows.

  It can be seen that the photopolymerization printing plate according to the present invention does not cause sensitizing dye crystal precipitation in the photosensitive layer over time, and the sensitivity change is small and good.

Claims (4)

In a photopolymerizable lithographic printing plate having a photopolymerizable photosensitive layer on a support, the photopolymerizable photosensitive layer contains at least a polymerizable compound having an ethylenically unsaturated group, a sensitizing dye, and a binder resin. A photopolymerization type lithographic printing plate having a dye-sensitive absorption maximum in the range of 300 nm to 500 nm and a solubility parameter (SP value) in the range of the following formula.
| SP value of sensitizing dye-SP value of a mixture of a polymerizable compound having an ethylenically unsaturated group and a binder resin | ≦ 8 MPa ^1/2 2. The photopolymerizable lithographic printing plate according to claim 1, further comprising a protective layer on the photopolymerizable photosensitive layer. The photopolymerizable lithographic printing plate according to claim 1 or 2, wherein the sensitizing dye has a melting point of less than 140 ° C. The photopolymerizable photosensitive layer contains the sensitizing dye according to claim 1, 2 or 3 and another sensitizing dye in a mass ratio of 1:10 to 100: 1. The photopolymerization type lithographic printing plate according to any one of to 3.