JP2009210636A - Original plate of planographic printing plate and method of producing planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate of a planographic printing plate superior in printing durability by being developed in aqueous development solution of pH 2 to 10 at high sensitivity and having a high developing speed, and to provide a method of producing the planographic printing plate. <P>SOLUTION: The original plate of the planographic printing plate has a photosensitive layer containing (A) a sensitizing coloring matter, (B) a polymerization initiator, (C) a polymerization compound, (D) a binder, and (E) a chain transfer agent on a support. At least any one of (C) the polymerization compound and (D) the binder has urethane bond, and (E) the chain transfer agent has urethane bond. The method of producing the planographic printing plate using the original plate is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor and a method for producing a lithographic printing plate using the original plate.

In general, a lithographic printing plate has a surface composed of an oleophilic image portion and a hydrophilic non-image portion. In lithographic printing, dampening water and oil-based ink are alternately applied to the plate surface, and the hydrophilic non-image area is dampened with a dampening water receiving area (ink non-receiving area) by utilizing the property that water and oil repel each other. ), After the ink is received only in the oleophilic image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer to be an image portion is left, and the other unnecessary image recording layer is removed with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by carrying out plate making by a method in which the surface of the hydrophilic support is exposed by dissolving and removing to form a non-image portion.

  In the conventional plate making process of a lithographic printing plate precursor, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary after exposure, but simplifies such additional wet processing. This is one of the issues. As one of simplification, it is desired that development can be performed with an aqueous solution close to neutrality or simple water.

  On the other hand, in recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread, and various new image output methods corresponding to such digitization technology have been put into practical use. It has come to be. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  From the background as described above, it is now more strongly desired than ever to adapt both the simplification of the plate making operation and the digitization.

  On the other hand, for example, in Patent Document 1, in an image forming layer of a lithographic printing plate precursor having an image forming layer containing a hydrophobic precursor, a hydrophilic resin, and a photothermal conversion agent on a hydrophilic support. In addition to the on-press development, it is further described that by using a compound having an ethylene oxide chain, it can be used for printing after being subjected to exposure, liquid development processing using water or a suitable aqueous solution as a developer. Yes.

Patent Document 2 contains (i) a hydrophilic support, and (ii) a radical polymerizable ethylenically unsaturated monomer, a radical polymerization initiator and an infrared absorbing dye, and is cured by infrared laser exposure. Moreover, a lithographic printing plate precursor comprising an oleophilic heat-sensitive layer containing 60% by mass or more of water and developable with an aqueous developer having a pH of 2 to 10 is prepared, exposed imagewise with an infrared laser, and an aqueous developer. A method for processing a lithographic printing plate precursor comprising removing an uncured region of the heat sensitive layer is described.
Patent Document 3 also describes a polymerized planographic printing plate precursor that is developed with a low pH developer.
JP 2002-365789 A US Patent Application Publication No. 2004/0013968 International Publication No. 05/111727 Pamphlet

However, in order to maintain developability with respect to an aqueous developer having a pH of 2 to 10, the photosensitive layer needs to be hydrophilic or highly water-permeable. However, the photosensitive layer cured by exposure has water resistance and film strength. As a result, the printing durability was insufficient.
An object of the present invention is to provide a lithographic printing plate precursor that can provide a lithographic printing plate that is highly sensitive, can be developed with an aqueous developer having a pH of 2 to 10, has a high development speed, and is excellent in printing durability, and the lithographic printing It is to provide a method for making a plate.

  The present inventor has found that the above problem can be solved by including a chain transfer agent having a urethane bond in the photosensitive layer. That is, the present invention is as follows.

<1> Lithographic printing having a photosensitive layer containing (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, (D) a binder, and (E) a chain transfer agent on a support. A lithographic printing plate, wherein at least one of (C) a polymerizable compound and (D) a binder has a urethane bond, and (E) a chain transfer agent has a urethane bond A printing plate master.

<2> The lithographic printing plate precursor as described in <1> above, wherein the (A) sensitizing dye has a maximum absorption in a wavelength range of 350 to 450 nm.
<3> The lithographic printing plate precursor as described in <1> or <2> above, wherein the (B) initiator compound is a hexaarylbiimidazole compound.

<4> The lithographic printing according to any one of <1> to <3>, wherein the chain transfer agent (E) having a urethane bond is a compound represented by the following general formula (I): Version original edition.

  In the formula, A represents an atomic group that forms a heterocycle with an N═C moiety, and has at least one urethane bond.

<5> The chain transfer agent having the (E) urethane bond is a compound represented by the following general formula (II) or (II ′), wherein any of the above <1> to <4> The lithographic printing plate precursor described.

  In the formula, B represents an atomic group that forms a heterocycle with the N═C moiety, L represents an m-valent linking group, and one of B and L has at least one urethane bond. m represents an integer of 2 or more.

<6> The lithographic printing plate precursor as described in any one of <1> to <5> above, wherein part or all of the components contained in the photosensitive layer are encapsulated in microcapsules.

<7> A method for preparing a lithographic printing plate, wherein the lithographic printing plate precursor according to any one of the above <1> to <6> is imagewise exposed and then developed with a developer.
<8> The method for preparing a lithographic printing plate precursor as described in <7> above, wherein the pH of the developer is from 2 to 10.

  According to the present invention, it is possible to provide a method for preparing a lithographic printing plate that can be developed with an aqueous developer having a pH of 2 to 10, has a high development speed and excellent printing durability, and a lithographic printing plate precursor used in this method. .

[Lithographic printing plate precursor]
First, the planographic printing plate precursor used in the present invention will be described.

<Photosensitive layer>
The photosensitive layer of the lithographic printing plate precursor according to the invention contains (A) a sensitizing dye, (B) an initiator compound, (C) a polymerizable compound, (D) a binder, and (E) a chain transfer agent. And at least one of (C) the polymerizable compound and (D) the binder has a urethane bond, and (E) the chain transfer agent has a urethane bond.
The photosensitive layer of the present invention can further contain other components as required. Hereinafter, the components of the photosensitive layer will be described in detail.

(A) Sensitizing dye The photosensitive layer of the invention contains a sensitizing dye. For example, by adding a sensitizing dye having a maximum absorption at 300 to 450 nm, a sensitizing dye having a maximum absorption at 500 to 600 nm, and an infrared absorber having a maximum absorption at 750 to 1400 nm, each is normally used in the industry. It is possible to provide a high-sensitivity lithographic printing plate corresponding to the 405 nm violet laser, 532 nm green laser, and 803 nm IR laser.
First, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described. Examples of such a sensitizing dye include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, and the like.

  Of the sensitizing dyes having an absorption maximum in a 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 (IX).

(In the general formula (IX), A represents an aromatic ring group or a heterocyclic group 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 represent 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 good.)

General formula (IX) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group. Represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Next, A in the general formula (IX) will be described. A represents an aromatic ring group or a heterocyclic group which may have a substituent. Specific examples of the aromatic ring or heterocyclic ring which may have a substituent include R ₁ in the general formula (IX). , R ₂ and R ₃ are the same.

  As specific examples of such sensitizing dyes, compounds described in JP-A 2007-58170, [0030] to [0031] are preferably used.

JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, JP 2007-316582, JP 2007-328243. The sensitizing dyes described in 1) can also be preferably used.
The preferred addition amount of the sensitizing dye is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and most preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photosensitive layer. It is the range of mass parts.

Subsequently, a sensitizing dye having a maximum absorption at 750 to 1400 nm that is preferably used in the present invention will be described in detail.
The sensitizing dye used here is highly sensitive to infrared laser irradiation (exposure) and is in an electronically excited state. The electron transfer, energy transfer, heat generation (photothermal conversion function), etc., associated with the electronically excited state are the photosensitive layer. It is presumed that it acts on a polymerization initiator coexisting therein to cause a chemical change in the polymerization initiator to generate a radical. In any case, the addition of a sensitizing dye having a maximum absorption at 750 to 1400 nm is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 to 1400 nm, and the conventional lithographic printing plate precursor Compared with this, high image forming properties can be exhibited.

  The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 750 nm to 1400 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷
And R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. In addition, Za ^-
Represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the photosensitive layer coating solution. Fluorophosphate ions and aryl sulfonate ions. In addition, the thing which does not contain a halogen ion as a counter ion is especially preferable.

  Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include

Examples thereof include those described in paragraph numbers [0017] to [0019] of JP-A-2001-133969.

  Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

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

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within this preferred particle size range, excellent dispersion stability of the pigment in the photosensitive layer can be obtained, and a uniform photosensitive layer can be obtained.

As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto.

  From the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer, these infrared absorbers are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the photosensitive layer. In the case of a dye, it is particularly preferably 0.5 to 10% by mass, and in the case of a pigment, it is particularly preferably 0.1 to 10% by mass.

(B) Polymerization initiator
The photosensitive layer of the present invention contains a polymerization initiator (hereinafter also referred to as an initiator compound). The initiator compound is a compound that undergoes a chemical change through the action of electron transfer, energy transfer, heat generation, etc. caused by the electronic excitation state of the sensitizing dye, and generates at least one selected from radicals, acids, and bases. is there. Hereinafter, radicals, acids, and bases generated in this way are simply referred to as active species. When the initiator compound is not present or when only the initiator compound is used alone, practically sufficient sensitivity cannot be obtained. As one mode in which a sensitizing dye and an initiator compound are used in combination, they can be used as a single compound by an appropriate chemical method (such as linking a sensitizing dye and an initiator compound through a chemical bond). It is.

  Usually, many of these initiator compounds are considered to generate active species through the initial chemical processes represented by the following (1) to (3). (1) Reductive decomposition of the initiator compound based on the electron transfer reaction from the electronically excited state of the sensitizing dye to the initiator compound, (2) Electron transfer from the initiator compound to the electronically excited state of the sensitizing dye (3) decomposition of the initiator compound from the electronically excited state based on energy transfer from the electronically excited state of the sensitizing dye to the initiator compound. Although it is often ambiguous as to which type of (1) to (3) each individual initiator compound belongs, the sensitizing dye in the present invention is extremely in combination with any of these types of initiator compounds. Shows a high sensitizing effect.

  As the initiator compound in the present invention, those known to those skilled in the art can be used without limitation, and specifically include, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds. , Hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable. Two or more of the above polymerization initiators can be used in combination as appropriate.

Examples of the hexaarylbiimidazole polymerization initiator include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) ) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2 , 2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5 ′ − Traphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

As other polymerization initiators, JP-A 2007-171406, JP-A 2007-206216, JP-A 2007-206217, JP-A 2007-225701, JP-A 2007-225702, JP-A 2007-316582, A polymerization initiator described in JP-A-2007-328243 can be preferably used.

The polymerization initiator in the present invention is preferably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0 mass%-10 mass%.

(C) Polymerizable compound The polymerizable compound used in the photosensitive layer in the invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond, preferably It is selected from compounds having 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 copolymers thereof, or mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. 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, isocyanuric acid ethylene oxide (EO) Examples include modified triacrylates and polyester acrylate oligomers.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, 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-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 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 No. 54-21726.

  Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. 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 general formula (A) to a polyisocyanate compound having two or more isocyanate groups Etc.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (A)
(However, R ₄ and R ₅ represent H or CH _3. )

Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable. Furthermore, 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 are used. Depending on the case, 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. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount and the like can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later. In addition, the use method of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer configuration and coating method such as undercoating and overcoating can be considered.

In the present invention, since the photosensitive layer contains (E) a chain transfer agent having a urethane bond, it is preferable to use a polymerizable compound having a urethane bond.
The molecular weight of the polymerizable compound having a urethane bond is generally about 100 to 1000, preferably about 200 to 7000, particularly preferably about 300 to 5000.
The polymerizable compound having a urethane bond can be synthesized by a known method, for example, from diisocyanate and polyhydric alcohol acrylic acid or methacrylic acid partial ester, or from polyhydric alcohol and monofunctional isocyanate acrylic acid. Or it can manufacture from a methacrylic acid partial ester.
Although the specific example of the polymeric compound which has a urethane bond is given to the following, it is not limited to these.

  The addition amount of the polymerizable compound including the polymerizable compound having a urethane bond is preferably 5 to 75% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 30% by mass with respect to the total solid content of the photosensitive layer. It is used in the range of 60% by mass.

<(A) Binder polymer>
As the binder polymer that can be used in the photosensitive layer of the invention, a binder polymer having a hydrophilic group is preferably used from the viewpoint of developability with respect to a developer.
The hydrophilic group is selected from monovalent or divalent or higher hydrophilic groups, for example, an alkyleneoxy group such as hydroxy group, sulfonic acid group, carboxylic acid group, phosphoric acid group, ethyleneoxy group, propyleneoxy group, Primary amino group, secondary amino group, tertiary amino group, salt obtained by neutralizing amino group with acid, quaternary ammonium group, amide group, ether group, carboxylic acid, sulfonic acid, phosphoric acid, etc. Salts obtained by neutralizing acid groups are preferred, especially primary amino groups, secondary amino groups, tertiary amino groups, salts obtained by neutralizing amino groups with acids, quaternary ammonium groups, amide groups, hydroxy groups. , —CH ₂ CH ₂ O—repeating unit or —CH ₂ CH ₂ NH—repeating unit is preferred, a tertiary amino group, a salt obtained by neutralizing an acid group with an amino group-containing compound, and neutralizing an amino group with an acid Salt, quaternary ammonium But most preferred.

  The binder polymer is preferably a copolymer, and the proportion of the copolymer component having a hydrophilic group as described above in the total copolymer components of the copolymer is 1 to 70 mol% from the viewpoint of developability. preferable. Considering compatibility between developability and printing durability, the content is more preferably 1 to 50 mol%, and particularly preferably 1 to 30 mol%.

  Furthermore, the binder polymer that can be used in the present invention preferably contains substantially no carboxylic acid group or phosphoric acid group from the viewpoints of developability and stain resistance.

Further, the acid value of the binder polymer (the acid content per 1 g of the polymer expressed as a chemical equivalent number) is preferably 0.3 meq / g or less, more preferably 0.1 meq / g or less. is there.
Moreover, it is preferable that the binder polymer used for this invention is insoluble with respect to water and aqueous solution of pH 10 or more. The solubility of the appropriate binder polymer in water (binder polymer concentration at the time of saturated dissolution) is 10% by mass or less, more preferably 1.0% by mass or less. The solubility measurement temperature is 25 ° C., which is a normal temperature during plate-making development.

The skeleton of such a binder polymer is preferably a polymer selected from acrylic resin, polyvinyl acetal resin, polyvinyl alcohol resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin. Of these, acrylic resins, methacrylic resins, vinyl copolymers such as styrene resins, and polyurethane resins are particularly preferable.
In particular, in the present invention, it is preferable to use a polyurethane resin which is a binder containing a urethane bond, from the viewpoint of improving printing durability by interaction with a chain transfer agent containing a urethane bond.

  The binder polymer used in the present invention preferably has a crosslinkable group. Here, the crosslinkable group is a group that crosslinks the binder polymer in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, etc. are mentioned, for example. Of these, an ethylenically unsaturated bond group is preferable. As the ethylenically unsaturated bond group, a styryl group, a (meth) acryloyl group, and an allyl group are preferable.

In the binder polymer, for example, free radicals (polymerization initiating radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and addition polymerization is performed directly between polymers or through a polymerization chain of the polymerizable compound. As a result, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.
The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.01 to 10.0 mmol, more preferably 0.05, per 1 g of the binder polymer. -5.0 mmol, most preferably 0.1-2.0 mmol.

  Further, from the viewpoint of improving printing durability, the crosslinkable group is desirably in the vicinity of the hydrophilic group, and the hydrophilic group and the crosslinkable group may be on the same polymer unit.

  The binder polymer used in the present invention includes, in addition to the unit having a hydrophilic group, a unit having a crosslinkable group, a unit having a hydrophilic group and a crosslinkable group, an alkyl (meth) acrylate or aralkyl ester unit. It is preferable to have. The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. Examples of (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

  The binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.

  The binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.

A binder polymer may be used independently or may be used in mixture of 2 or more types. The content of the binder polymer is preferably from 5 to 75 mass%, more preferably from 10 to 70 mass%, more preferably from 10 to 70 mass%, based on the total solid content of the photosensitive layer, from the viewpoint of good image area strength and image formability. More preferably, it is 60 mass%.

  The total content of the polymerizable compound and the binder polymer is preferably 80% by mass or less based on the total solid content of the photosensitive layer. If it exceeds 80% by mass, the sensitivity and developability may be lowered. More preferably, it is 35-75 mass%.

  Specific examples of polymer units constituting the binder polymer binder polymer used in the present invention and specific examples of the binder polymer binder polymer are shown below, but the present invention is not limited to these examples.

  Specific examples of the additive binder polymer are listed below, but are not limited thereto. The mass average molecular weight (Mw) in the table is measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

(E) Chain transfer agent having a urethane bond The photosensitive layer of the invention contains a chain transfer agent having a urethane bond. Chain transfer agents contribute to improved sensitivity and storage stability. Any compound that acts as a chain transfer agent and has a urethane bond is not particularly limited. As the compound acting as a chain transfer agent, for example, a compound having SH, PH, SiH, GeH in the molecule is selected and used. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals. Among them, a compound having an SH group, particularly a compound represented by the following general formula (I) is preferable.
By using such a thiol compound as a chain transfer agent, the problem of odor and the decrease in sensitivity due to evaporation from the photosensitive layer or diffusion to other layers are avoided, and the storage stability is excellent and the developability is good. Since there are few residual colors and residues later, there is little contamination during printing, and a lithographic printing plate precursor with high sensitivity and high printing durability can be obtained.

In the formula, A represents an atomic group that forms a heterocycle with an N═C moiety, and has at least one urethane bond.
The compound represented by the general formula (I) has a keto-enol tautomer, and shows an enol structure here, but the present invention also includes a keto structure.

  The heterocycle in the general formula (I) is a 5-membered or higher ring containing at least one of N, S and O, may have a substituent, and may contain a condensed ring.

Examples of preferred heterocycles include, for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, Indoles, indazoles, purines, quinolidines, isoquinolines, phthalazines, naphthyridines, quinazolines, sinolines, pteridines, carbazoles, carbolines, phenanthrines, acridines, perimidines, phenanthrolins, phthalazines, phenazazines, phenoxazines, furansans, etc. Further, it may be benzo-fused and may have a monovalent substituent.

  Examples of monovalent substituents include halogen atoms, amino groups, substituted amino groups, substituted carbonyl tombs, hydroxyl groups, substituted oxy groups, silyl groups, nitro groups, cyano groups, alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. A heterocyclic group, a sulfo group, a substituted sulfonyl group, a sulfonate group, a substituted sulfinyl group, a phosphono group, a substituted phosphono group, a phosphonato group, a substituted phosphonato group, and the like. It may be.

  Specific examples of the compound represented by formula (I) are shown below, but are not limited thereto.

  Furthermore, the compound which has 2 or more in the molecule | numerator which produces | generates a radical by the said deprotonation from the surface of a sensitivity and printing durability is preferable. In particular, a compound having two or more SH groups, for example, a compound represented by the following general formula (II) or (II ′) is preferable.

In the formula, B represents an atomic group that forms a heterocycle together with the N═C moiety. L represents an m-valent linking group. Either B or L has at least one urethane bond. m represents an integer of 2 or more.

The compound represented by the general formula (II) and the compound represented by the general formula (II ′) have a keto-enol tautomer relationship.
The heterocycle in the general formula (II) or (II ′) may be monocyclic or polycyclic (fused ring), and may be an alicyclic ring or an aromatic ring. .
Preferred examples of the hetero ring include a triazole ring, an oxadiazole ring, a thiadiazole ring, a benzimidazole ring, a benzoxazole ring, a benzthiazole ring, and a tetrazole ring.

  Although the specific example of a compound represented by general formula (II) is shown below, it is not limited to these. Here, an enol structure is shown, but the present invention also includes a keto structure.

The amount of the chain transfer agent having a urethane bond is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, and still more preferably 1.0 to 1.0% by mass with respect to the total solid content of the photosensitive layer. 10% by mass.
The chain transfer agent having a urethane bond of the present invention can be produced, for example, by reacting an amino group-containing chain transfer agent with an alkyl chloroformate compound. Moreover, it can manufacture also by the method of introduce | transducing SH group into a compound which has a urethane bond using a substitution reaction.
Moreover, when using together chain transfer agents other than the chain transfer agent which has a urethane bond as needed, it is preferable to use together the chain transfer agent which does not have a hydrophilic group.
The chain transfer agent used in combination is preferably 50% by mass or less based on the chain transfer agent having a urethane bond.

<Microcapsule>
In the present invention, as a method for causing the photosensitive layer to contain the above-described photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

  As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<Other photosensitive layer components>
The photosensitive layer of the present invention can further contain various additives as required. Additives include surfactants for promoting developability and improving the surface of the coating, hydrophilic polymers for improving developability and dispersion stability of microcapsules, and visual and non-image areas visible A colorant and a print-out agent, a polymerization inhibitor for preventing unnecessary thermal polymerization of radically polymerizable compounds during production or storage of the photosensitive layer, a higher fat derivative for preventing polymerization inhibition by oxygen, Inorganic fine particles for improving the strength of the cured film in the image area, hydrophilic low molecular weight compounds for improving developability, co-sensitizers for improving sensitivity, plasticizers, and the like can be added. Any known compounds can be used, such as JP2007-171406, JP2007-206216, JP2007-206217, JP2007-225701, JP2007-225702, The compounds described in JP2007-316582A and JP2007-328243A can be used.

<Formation of photosensitive layer>
The photosensitive layer of the present invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photosensitive layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

The coating, the photosensitive layer coating amount on the support obtained after drying (solid content) may be varied according to the intended purpose, generally 0.3 to 3.0 g / m ² is preferred. Within this range, good sensitivity and good film properties of the photosensitive layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is preferably provided on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer used in the present invention preferably has an oxygen permeability A at 25 ° C. and 1 atm of 1.0 ≦ A ≦ 20 (mL / m ² · day). When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably in the range of 1.5 ≦ A ≦ 12 (mL / m ² · day), further preferably 2.0 ≦ A ≦ 10.0 (mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  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, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. Or they can be mixed. Of these, the use of polyvinyl alcohol as the 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 that are hydrolyzed by 71 to 100 mol% and have a polymerization repeating unit 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, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

  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 higher the film thickness, the higher the oxygen barrier property and the more advantageous in terms of sensitivity. The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) can be in the range of 2000 to 10 million, preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.

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 photosensitive 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. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 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 adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. As for the method of coating such a protective layer, for example, US Pat. No. 3,458,311 and JP-B-5
This is described in detail in Japanese Patent No. 5-49729.

Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin flat plate shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any one of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.
In the present invention, among the inorganic layered compounds described above, fluorine-based swellable synthetic mica that is a synthetic inorganic layered compound is particularly useful.
The aspect ratio of the inorganic layered compound of the present invention is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  The dispersion method of the inorganic stratiform compound used for the protective layer is disclosed in JP2007-171406, JP2007-206216, JP2007-206217, JP2007-225701, JP2007-225702, and JP2007. The methods described in JP-A-316582 and JP-A-2007-328243 are used.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

[Support]
The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate,
Cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which the above-mentioned metal is laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. 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 preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to the roughening treatment of the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, 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.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferable compounds include compounds having a polymerizable group such as a methacryl group or an allyl group and a support adsorbing group such as a sulfonic acid group, a phosphoric acid group, or a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Plate making method]
A lithographic printing plate is prepared by subjecting the lithographic printing plate precursor according to the invention to image exposure and development. Development processing includes (a) a method of developing with an alkaline developer (pH is greater than 10), (b) a method of developing with a developer having a pH of 2 to 10, and (c) a wet on a printing press. A method (on-press development) of developing while adding water and / or ink is mentioned. In the present invention, although not particularly limited, a method of developing with a developer having a pH of 2 to 10 is preferred.
That is, the lithographic printing plate precursor of the present invention can be set on a printing machine and printed immediately after the protective layer and the photosensitive layer in the non-exposed area are removed together with a developer having a pH of 2 to 10.
In addition, such processing in an automatic developing machine has an advantage that it is freed from dealing with development residue derived from the protective layer / photosensitive layer that occurs in the case of on-press development.

The developer used in the present invention is an aqueous solution having a pH of 2 to 10. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution having the same composition as that of a generally known fountain solution, a surfactant (anionic, nonionic, An aqueous solution containing a cationic system or the like, or an aqueous solution containing a water-soluble polymer compound is preferable. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the developer is more preferably 3-8, and even more preferably 4-7.
When an acidic to neutral developer is used, it is preferable to contain either an organic acid or an inorganic acid. By containing an organic acid or an inorganic acid, developability can be improved during plate making, and it is possible to suppress the occurrence of stains in the non-image area of the plate that has been made.

  The anionic surfactant used in the developer of the present invention is not particularly limited, but dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are preferably used.

The cationic surfactant used in the developer of the present invention is not particularly limited, and conventionally known ones can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants used in the developer of the present invention include sorbitol and / or sorbitan fatty acid ester ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide). -Ethylene oxide) block copolymers and fatty acid esters of polyhydric alcohols are preferably used.

  Two or more surfactants may be used, and the ratio of the surfactant contained in the developer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

  Examples of the water-soluble polymer compound used in the developer of the present invention include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan. , Polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. It is done.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.

  Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  Further, the developer of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). , Xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, tricrene, monochlorobenzene, etc.) and polar solvents.

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  In addition to the above, the developer of the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

  The developer described above can be used as a developer and developer replenisher for the exposed negative lithographic printing plate precursor, and is preferably applied to an automatic processor described later. When developing using an automatic processor, the developing solution becomes fatigued according to the amount of processing, so the processing capability may be restored using a replenisher or a fresh developer. This replenishing method is also preferably applied to the lithographic printing plate making method of the present invention.

  The development treatment with an aqueous solution having a pH of 2 to 10 in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while transporting a lithographic printing plate precursor after image recording, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image recording set thereon while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100554, or Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows. A brush roll can be used in which the groove mold material is radially wound around a plastic or metal roll as a core without a gap.
The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene) can be used. For example, the fiber has a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm. Can be used.
Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.
Moreover, it is preferable to use two or more rotating brush rolls.

  The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the conveying direction of the planographic printing plate precursor of the present invention. Thus, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the heat sensitive layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized. In the desensitizing treatment, a known desensitizing solution can be used.

  In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. 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 100-500 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.

Prior to the above development processing, the lithographic printing plate precursor is exposed imagewise by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data.
A desirable light source wavelength is preferably 350 nm to 450 nm or 700 nm to 1200 nm. In the case of 350 nm to 450 nm, a lithographic printing plate precursor having a sensitizing dye having an absorption maximum in this region in the photosensitive layer is used, and in the case of 700 nm to 1200 nm, infrared absorption which is a sensitizing dye having absorption in this region. A lithographic printing plate precursor containing an agent is used. A semiconductor laser is suitable as a light source of 350 nm to 450 nm. As a light source of 700 nm to 1200 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable.
The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

(Production of support)
In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using a 15% by mass sulfuric acid aqueous solution (containing 0.5% by mass of aluminum ions) as an electrolyte, then washed with water and dried. .
The centerline average roughness Ra (JIS B0601) of the surface of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Further, the following undercoat liquid (1) was bar-coated and then oven-dried at 80 ° C. for 10 seconds to prepare a support having an undercoat layer having a dry coating amount of 10 mg / m ² .

<Undercoat liquid (1)>
・ Undercoat compound (1) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

[Preparation of lithographic printing plate precursor (1)]
A photosensitive layer coating solution (1) having the following composition was bar coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and a photosensitive layer having a dry coating amount of 1.1 g / m ² . A protective layer coating solution (1) having the following composition is applied on the substrate using a bar so that the dry coating amount is 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds. A lithographic printing plate precursor (1) was obtained.

<Photosensitive layer coating solution (1)>
-Binder polymer (P-20) (mass average molecular weight 59,000) 0.54 g
・ Polymerizable compound 0.40g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
・ Polymerizable compound Ethoxylated trimethylolpropane triacrylate 0.08 g
(Nippon Kayaku Co., Ltd., SR9035, EO addition mole number 15, molecular weight 1000)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (1) 0.18 g
・ The following chain transfer agent (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder polymer (1): 10 parts by mass, solvent cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt ・ The following water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (1)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 0.5g
Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
950g of water

Furthermore, when the oxygen permeability of the protective layer was measured under the following conditions, the oxygen permeability of the protective layer was 3.8 ml / (m ² · day · atom).

(Measurement of oxygen permeability)
A protective layer was applied to the surface of a photographic paper base having a thickness of about 200 μm and coated on both sides with polyethylene having a thickness of about 200 μm, and then dried to prepare a sample for measurement. . The oxygen permeability of the photographic paper base paper measured in advance was about 700 ml / (m ² · day · atom) under the following measurement conditions, and was sufficiently negligible when measuring the oxygen permeability in the protective layer. .
Using the sample thus obtained, according to the gas permeability test method described in JIS K7126B and ASTM D3985, oxygen permeation was performed at 25 ° C. and 60% RH using OX-TRAN 2/20 manufactured by Mocon. The rate [ml / (m ² · day · atom)] was measured.

[Preparation of lithographic printing plate precursors (2) to (4)]
The same as the lithographic printing plate precursor (1) except that the chain transfer agent (1) in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) is replaced with the following chain transfer agents (2) to (4), respectively. Thus, lithographic printing plate precursors (2) to (4) were obtained.
[Preparation of lithographic printing plate precursor (5)]
The lithographic printing plate precursor (1), except that the polymerizable compound isocyanuric acid EO-modified triacrylate in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) is replaced with the polymerizable compound (M-1). Similarly, a lithographic printing plate precursor (5) was obtained.

[Preparation of comparative planographic printing plate precursor (1)]
Except for replacing the chain transfer agent (1) in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) with the following comparative chain transfer agent (1), as in the lithographic printing plate precursor (1), A comparative lithographic printing plate precursor (1) was obtained.

[Preparation of comparative planographic printing plate precursor (2)]
Except for replacing the chain transfer agent (1) in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) with the following comparative chain transfer agent (2), as in the lithographic printing plate precursor (1), A comparative lithographic printing plate precursor (1) was obtained.

[Preparation of comparative planographic printing plate precursor (3)]
A comparative lithographic printing plate precursor (3) is obtained in the same manner as the lithographic printing plate precursor (1) except that the chain transfer agent (1) in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) is excluded. It was.
[Preparation of comparative planographic printing plate precursor (4)]
The chain transfer agent (1) in the photosensitive layer coating solution (1) of the lithographic printing plate precursor (1) is replaced with the following comparative chain transfer agent (1), and the polymerizable compound isocyanuric acid EO-modified triacrylate is polymerized. A comparative lithographic printing plate precursor (4) was obtained in the same manner as in the lithographic printing plate precursor (1) except that the compound (M-1) was used.

[Examples 1 to 5 and Comparative Examples 1 to 4]
(1) Exposure, development and printing For each of the above lithographic printing plate precursors (1) to (5) and comparative lithographic printing plate precursors (1) to (4), the energy density was measured using a 405 nm semiconductor laser with an output of 100 mW. The imagewise exposure was performed with a change.
Thereafter, the developing solution (1) having the following composition was used, and development processing was carried out with an automatic developing processor having a structure shown in FIG. The pH of the developer was 4.6. The automatic processor is an automatic processor having two rotating brush rolls. As the rotating brush roll, the first brush roll and the polybutylene terephthalate fiber (hair diameter 200 μm, hair length 17 mm). Using a brush roll with an outer diameter of 90 mm implanted with 200 mm / min in the same direction as the conveying direction (peripheral speed 0.94 m / sec at the tip of the brush), the second brush roll is made of polybutylene terephthalate Using a brush roll having an outer diameter of 60 mm in which fibers (hair diameter: 200 μm, hair length: 17 mm) were planted, it was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip: 0.63 m / sec). . The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the developer was 10 liters.

Developer (1)
・ Water 100g
・ Benzyl alcohol 1g
・ Polyoxyethylene naphthyl ether (oxyethylene average number n = 13) 1g
・ Dioctyl sulfosuccinate sodium salt 0.5g
・ 1g gum arabic
・ Ethylene glycol 0.5g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

Next, the developed lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (an etchant manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 ( Capacity ratio)) and TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.)
And a printing speed of 6000 sheets per hour.

(2) Evaluation The lithographic printing plate precursor was evaluated for sensitivity, developability, transport speed and printing durability as follows. The results are shown in Table 1.

<Sensitivity>
After 100 sheets were printed as described above and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were printed continuously. In the 600th printed matter in total, the exposure amount (mJ / cm ² ) with no unevenness in the ink density in the image area was evaluated as sensitivity.
<Developability>
The lithographic printing plate precursor was exposed and developed as described above, the non-image area of the obtained lithographic printing plate was visually confirmed, and the presence or absence of the remaining photosensitive layer was evaluated according to the following criteria.
○: No remaining film, Δ: Slightly remaining film, ×: Residual film <Conveying speed>
The conveyance speed of the lithographic printing plate precursor was changed using the above automatic developing processor, and the maximum conveyance speed (cm / min) capable of completely removing the non-image area was determined. The faster the conveyance speed, the higher the developability.
<Print durability>
When printing was performed as described above, as the number of printed sheets increased, the image area was gradually worn out and the ink receptivity was lowered, so that the ink density in the printing paper was lowered. Printing durability was evaluated based on the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.

As is apparent from the results shown in Table 1, the lithographic printing plate precursor using the chain transfer agent having a urethane bond of the present invention for the photosensitive layer is excellent in sensitivity, developability, transport speed and printing durability. The lithographic printing plate precursor (5) in which the binder polymer and the polymerizable compound both have a urethane bond is particularly excellent in sensitivity and printing durability.
On the other hand, the comparative lithographic printing plate precursor (1) using a chain transfer agent having no urethane bond for the photosensitive layer has a poor conveying speed and a slightly poor printing durability. The comparative lithographic printing plate precursor (2) using a chain transfer agent having a hydrophilic group (carboxyl group) for the photosensitive layer is slightly inferior in printing durability. Furthermore, the comparative lithographic printing plate precursor (3) that does not use a chain transfer agent in the photosensitive layer has very low sensitivity and does not substantially form an image. In the comparative lithographic printing plate precursor (4) in which the binder polymer and the polymerizable compound both have urethane bonds, the sensitivity is improved compared to the comparative lithographic printing plate precursor (1), but the conveyance speed and printing durability are increased. Is still inferior, and the difference is clear when compared with the planographic printing plate precursor (5).

The structure of an automatic processor is shown.

Explanation of symbols

1: rotating brush roll 2: receiving roll 3: transport roll 4: transport guide plate 5: spray pipe 6: pipeline 7: filter 8: plate supply table 9: plate discharge table 10: developer tank 11: circulation pump 12: plate

Claims (8)

  A lithographic printing plate precursor having a photosensitive layer containing (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, (D) a binder, and (E) a chain transfer agent on a support. A lithographic printing plate precursor, wherein at least one of (C) a polymerizable compound and (D) a binder has a urethane bond, and (E) the chain transfer agent has a urethane bond .   The lithographic printing plate precursor as claimed in claim 1, wherein the (A) sensitizing dye has a maximum absorption in a wavelength range of 350 to 450 nm.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the initiator compound (B) is a hexaarylbiimidazole compound. The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the (E) chain transfer agent having a urethane bond is a compound represented by the following general formula (I).

In the formula, A represents an atomic group that forms a heterocycle with an N═C moiety, and has at least one urethane bond. The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the chain transfer agent (E) having a urethane bond is a compound represented by the following general formula (II) or (II '): .

In the formula, B represents an atomic group that forms a heterocycle with the N═C moiety, L represents an m-valent linking group, and one of B and L has at least one urethane bond. m represents an integer of 2 or more.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein some or all of the components contained in the photosensitive layer are encapsulated in microcapsules.   A method for producing a lithographic printing plate, comprising: exposing the lithographic printing plate precursor according to any one of claims 1 to 6 in an imagewise manner and then developing the same with a developer.   The method for preparing a lithographic printing plate according to claim 7, wherein the pH of the developer is 2 to 10.

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