JP2016156968A - Positive lithographic printing plate precursor and method for manufacturing lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive lithographic printing plate precursor that gives a lithographic printing plate excellent in printing durability and chemical resistance even when the printing plate is subjected to a burning treatment, in a lithographic printing plate using a binder resin that easily induces pyrolysis (for example, a polyurea resin or a polyurethane resin), and a method for manufacturing a lithographic printing plate.SOLUTION: The positive lithographic printing plate precursor has an image recording layer described below on a support body: the image recording layer comprises a polymer having a urea bond and/or a urethane bond in the main chain as a component A, an infrared ray-absorbing material as component B, and a compound having a block isocyanate group as component C.SELECTED DRAWING: None

Description

  The present invention relates to a positive lithographic printing plate precursor and a method for producing a lithographic printing plate, and more particularly to a positive lithographic printing plate precursor including a burning treatment step and a lithographic printing plate production method.

Conventionally, various photosensitive compositions have been used as visible image forming materials and lithographic printing plate materials. In particular, the development of lasers in the field of lithographic printing has been remarkable in recent years. Particularly, solid lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can be easily obtained with high output and small size. ing. In the field of lithographic printing, these lasers are very useful as an exposure light source for making a plate directly from digital data such as a computer.
The positive lithographic printing plate precursor for infrared laser contains an alkali-soluble binder resin and an IR dye that absorbs light and generates heat as essential components. The IR dye or the like acts as a development inhibitor that substantially reduces the solubility of the binder resin in the developer by interaction with the binder resin in the unexposed area (image area), and in the exposed area (non-image area). The generated heat weakens the interaction between the IR dye and the binder resin and dissolves in an alkaline developer to form a lithographic printing plate.
As conventional lithographic printing plate precursors, those described in Patent Documents 1 to 3 are known.

JP 2007-17913 A Japanese Patent Laid-Open No. 10-268512 JP 2005-215651 A

The performance required for the positive type lithographic printing plate precursor includes, for example, developability of the exposed portion, printing durability of the obtained lithographic printing plate, chemical resistance to a plate cleaner used during printing, etc. is there. In response to such demands, some positive lithographic printing plates can obtain high printing durability by performing high-temperature heat treatment (so-called burning treatment) after exposure and development.
It is also known that a printing plate having excellent printing durability can be obtained by using a urea polymer or urethane polymer as one of the binder resins (see, for example, Patent Document 1). However, in order to further improve the chemical resistance and printing durability of printing plates using urea polymers and urethane polymers, when the burning treatment is performed, the polymer is decomposed by heating, and the printing durability and chemical resistance are lowered. There was a case. Thus, there has been a demand for a technique that improves the printing durability and chemical resistance even when a printing plate using such a binder resin having a low heat resistance is burned.
As a conventional technique for improving printing durability and chemical resistance by a burning process, for example, a technique using a novolac resin as a main binder has been proposed (see, for example, Patent Document 2). Improvement in printing durability has been realized. However, this recording layer has a problem of poor chemical resistance. In addition, a method using a modified phenolic resin (see, for example, Patent Document 3) is also known, but the effect was insufficient when applied to a printing plate mainly composed of a binder resin having low heat resistance.

  The problem to be solved by the present invention is that the lithographic printing plate using a binder resin (for example, a polyurea resin or a polyurethane resin) that easily undergoes thermal decomposition has excellent printing durability and chemical resistance even when performing a burning treatment. A positive lithographic printing plate precursor from which a lithographic printing plate can be obtained and a method for producing the lithographic printing plate.

The above-described problems of the present invention have been solved by the means described in <1> or <21> below. It describes below with <2>-<20> and <22> which are preferable embodiments.
<1> An image recording layer comprising, as component A, a polymer having a urea bond and / or a urethane bond in the main chain, an infrared absorbing material as component B, and a compound having a blocked isocyanate group as component C, A positive lithographic printing plate precursor having a support on a support,
<2> The positive lithographic printing plate precursor as described in <1>, wherein the blocked isocyanate group is a group represented by the following formula C-1.

  In formula C-1, Z represents a monovalent organic group.

<3> The positive lithographic printing plate precursor as described in <1> or <2>, wherein the component A is a polymer having a urea bond in the main chain,
<4> The positive planographic printing plate precursor according to any one of <1> to <3>, wherein Component C is a polymer having a blocked isocyanate group,
<5> The positive lithographic printing plate precursor as described in <4>, wherein the polymer having a blocked isocyanate group has a structural unit represented by the following formula C-2.

In Formula C-2, R ^C1 represents a hydrogen atom or a methyl group, X and Y each independently represent a divalent linking group or a single bond, and Z represents a monovalent organic group.

<6> The positive planographic printing plate precursor according to <5>, wherein X is an arylene group or —C (═O) —.
<7> The positive lithographic printing plate precursor as described in <6>, wherein X is —C (═O) —,
<8> The positive lithographic printing plate precursor as described in any one of <4> to <7>, wherein the polymer having a blocked isocyanate group further has an acidic group,
<9> The positive lithographic printing plate precursor according to <8>, wherein the acidic group is at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, and a carboxylic acid group,
<10> Z is a group obtained by removing one active hydrogen from a compound selected from the group consisting of a compound having a phenolic hydroxyl group, an oxime compound, a compound having a pyrazole structure, a lactam compound, and an aliphatic alcohol compound. A positive lithographic printing plate precursor as described in <2> or <5>,
<11> The positive lithographic printing plate precursor as described in any one of <1> to <3>, wherein Component C is a compound having a blocked isocyanate group and a molecular weight of less than 1,000,
<12> The positive lithographic printing plate precursor as described in <11>, wherein Component C is a compound having a molecular weight of less than 1,000 and having three or more blocked isocyanate groups,
<13> The positive planographic printing plate according to any one of <1> to <12>, wherein the content of component C is 1 to 30 parts by mass with respect to 100 parts by mass of component A Original,
<14> The positive-type planographic printing plate precursor according to any one of <1> to <13>, wherein the image recording layer further contains a phenol resin as component D,
<15> The positive lithographic printing plate precursor as described in any one of <1> to <14>, wherein the component A further has an acidic group,
<16> The positive lithographic printing plate precursor as described in <15>, wherein the acidic group in component A is an acidic group directly bonded to the main chain,
<17> The positive lithographic plate according to <15> or <16>, wherein the acidic group in component A is at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, and a carboxylic acid group. Printing plate master,
<18> The positive lithographic printing plate precursor as described in <17>, wherein the acidic group in component A is a phenolic hydroxyl group,
<19> Any of <1> to <18>, wherein the image recording layer is composed of a lower layer and an upper layer, and the image recording layer containing component A to component C is at least one of the lower layer and the upper layer Or positive lithographic printing plate precursor as described in
<20> The positive planographic printing plate precursor as described in <19>, wherein the image recording layer containing component A to component C is at least the lower layer,
<21> An exposure process for image exposure of the positive planographic printing plate precursor according to any one of <1> to <20>, and a development process for developing using an alkaline aqueous solution having a pH of 8.5 to 13.5 A method for producing a lithographic printing plate, comprising:
<22> The method for preparing a lithographic printing plate as described in <21>, further comprising a heating step of performing a heat treatment after the developing step.

  According to the present invention, in a lithographic printing plate using a binder resin (for example, a urea resin or a urethane resin) that easily undergoes thermal decomposition, a lithographic printing plate excellent in printing durability and chemical resistance can be obtained even when performing a burning treatment. The positive type lithographic printing plate precursor obtained and a method for producing the lithographic printing plate can be provided.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the specification of the present application, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
Furthermore, the geometrical isomer which is the substitution mode of the double bond in each general formula is not limited to the E-form or the Z-form unless otherwise specified. Or a mixture thereof.
In addition, the chemical structural formula in this specification may be expressed as a simplified structural formula in which a hydrogen atom is omitted.
In this specification, “(meth) acrylate” represents acrylate and methacrylate, “(meth) acryl” represents acryl and methacryl, “(meth) acryloyl” represents acryloyl and methacryloyl, and “(meth) ) Acrylamide "refers to acrylamide and methacrylamide. The “acrylic resin” is a homopolymer or copolymer of a compound selected from the group consisting of a (meth) acrylate compound and a (meth) acrylamide compound. It is assumed that the resin is copolymerized by 50% by mass or more.
In the present invention, “mass%” and “wt%” are synonymous, and “part by mass” and “part by weight” are synonymous.
In the present invention, a combination of two or more preferred embodiments is a more preferred embodiment.

  In the present invention, unless otherwise specified, the molecular weight in the polymer component is a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

(Positive planographic printing plate precursor)
The positive-type planographic printing plate precursor (hereinafter also simply referred to as “lithographic printing plate precursor”) of the present invention is a component A, a polymer having a urea bond and / or a urethane bond in the main chain, and a component B as an infrared absorbing material. And an image recording layer (also referred to as “photosensitive layer”) containing, as Component C, a compound having a blocked isocyanate group, on the support.

As a result of diligent study, the present inventor has an image recording layer containing the above components A to C, so that in a lithographic printing plate using a binder resin (for example, a urea resin or a urethane resin) that easily undergoes thermal decomposition, It has been found that a lithographic printing plate excellent in printing durability and chemical resistance can be obtained even by performing the burning treatment, and the present invention has been completed.
The mechanism of the effect in the present invention is not clear, but is presumed as follows.
Urea polymers and urethane polymers are considered to have decomposed into oligomers with molecular weights of about several thousand or monomer units with molecular weights of about several hundreds by the burning treatment, so that the printing durability and chemical resistance are deteriorated compared to before burning. It is inferred that he has been invited. At this time, it is considered that the terminal of the oligomer or monomer which is a decomposition product has an amino group. On the other hand, the blocked isocyanate group of the compound having a blocked isocyanate group is considered to be deprotected by heating to generate a reactive isocyanate group. It is speculated that these isocyanate groups react with the amino group of the decomposition product to form bonds again, thereby improving the printing durability and chemical resistance.
At this time, if the compound having a blocked isocyanate group is trifunctional or more, the product of repolymerization can take a three-dimensional network structure, and therefore the effect of the invention is estimated to be greater.

Component A: Polymer having urea bond and / or urethane bond in main chain The positive planographic printing plate precursor of the present invention is a polymer having urea bond and / or urethane bond in main chain as component A in the image recording layer. (Also simply referred to as “component A” or “urea / urethane resin”).
The urea / urethane resin used in the present invention is not particularly limited as long as it is a conventionally known resin, and is a polymer having either a urea bond or a urethane bond, or both a urea bond and a urethane bond in the main chain. For example, the following is used.

Component A is preferably a polymer having at least a urea bond in the main chain, and more preferably a polyurea resin having at least a urea bond in the main chain. The above aspect is more excellent in printing durability and chemical resistance of the resulting lithographic printing plate.
The urea bond is a bond represented by the following formula U-1, and in Component A, the urea bond is preferably a bond represented by the following formula U-2.

In the formula, R ^U1 and R ^U2 each independently represent a hydrogen atom or an alkyl group, and a wavy line represents a bonding position with another structure.
R ^U1 and R ^U2 are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.). It is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or a methyl group.

  The urea bond may be formed by any means, but can be obtained by a reaction between an isocyanate compound and an amine compound. In addition, a hydroxyl group or a terminal is formed at the terminal, such as 1,3-bis (2-aminoethyl) urea, 1,3-bis (2-hydroxyethyl) urea, 1,3-bis (2-hydroxypropyl) urea, and the like. A macromonomer may be synthesized using a urea compound substituted with an alkyl group having an amino group as a raw material.

The isocyanate compound used as a raw material is not particularly limited as long as it is a polyisocyanate compound having two or more isocyanate groups in the molecule, but a diisocyanate compound is preferable.
Examples of the polyisocyanate compound include 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,3-cyclopentane diisocyanate, 9H-fluorene. -2,7-diisocyanate, 9H-fluoren-9-one-2,7-diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, tolylene-2,4-diisocyanate, Tolylene-2,6-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 2,2-bis (4-isocyanatophenyl) hexafluoropropane, 1,5-diisocyanate And naphthalene.

The amine compound used as a raw material is preferably a polyamine compound having two or more amino groups in the molecule, and more preferably a diamine compound.
Examples of polyamine compounds include 2,7-diamino-9H-fluorene, 3,6-diaminoacridine, acriflavine, acridine yellow, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-diamino Benzophenone, bis (4-aminophenyl) sulfone, 4,4′-diaminodiphenyl ether, bis (4-aminophenyl) sulfide, 1,1-bis (4-aminophenyl) cyclohexane, 4,4′-diaminodiphenylmethane, 3 3,3'-diaminodiphenylmethane, 3,3'-diaminobenzophenone, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4- (phenyldiazenyl) benzene-1,3-diamine, 1,5-diaminonaphthalene 1,3-phenylenediamine, 2,4-diaminoto Ruene, 2,6-diaminotoluene, 1,8-diaminonaphthalene, 1,3-diaminopropane, 1,3-diaminopentane, 2,2-dimethyl-1,3-propanediamine, 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, N, N-bis (3-aminopropyl) methylamine, 1,3-diamino-2-propanol, diethylene glycol bis (3-aminopropyl) Ether, m-xylylenediamine, tetraethylenepentamine, 1,3-bis (aminomethyl) cyclohexane, benzoguanamine, 2,4-diamino-1,3,5-triazine, 2,4-diamino-6-methyl- 1,3,5-triazine, 6-chloro-2,4-diaminopyrimidine, 2-chloro-4,6-diamino- , 3,5-triazine. These polyamine compounds may be reacted with phosgene or triphosgene to synthesize polyisocyanate compounds and used as macromonomer raw materials.

  The polyurea resin in component A is preferably a linear polyurea resin, and more preferably a polyurea resin obtained by polycondensation of a diisocyanate compound and a diamine compound.

As the component A, a polymer having at least a urethane bond in the main chain can also be used.
The urethane bond is a bond represented by the following formula T-1, and in Component A, the urethane bond is preferably a bond represented by the following formula T-2.

In the formula, R ^T1 represents a hydrogen atom or an alkyl group, and a wavy line portion represents a bonding position with another structure.
R ^T1 is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.), hydrogen It is more preferably an atom or an alkyl group having 1 to 5 carbon atoms, and further preferably a hydrogen atom or a methyl group.

The urethane bond may be formed by any means, but can be obtained by a reaction between an isocyanate compound and a compound having a hydroxy group.
The isocyanate compound used as a raw material is preferably a polyisocyanate compound having two or more isocyanate groups in the molecule, and more preferably a diisocyanate compound. As a polyisocyanate compound, the polyisocyanate compound mentioned by the said urea bond can be mentioned.
Examples of the compound having a hydroxy group used as a raw material include a polyol compound, an aminoalcohol compound, an aminophenol compound, and an alkylaminophenol compound, and a polyol compound or an aminoalcohol compound is preferable.
The polyol compound is a compound having at least two or more hydroxy groups in the molecule, and is preferably a diol compound. Moreover, you may have an ester bond or an ether bond in a molecule | numerator.
Examples of the polyol compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexane. Dimethanol, pentaerythritol, 3-methyl-1,5-pentanediol, poly (ethylene adipate), poly (diethylene adipate), poly (propylene adipate), poly (tetramethylene adipate), poly (hexamethylene adipate), poly (Neopentylene adipate) and the like.
The amino alcohol compound is a compound having an amino group and a hydroxy group in the molecule, and may further have an ether bond in the molecule. Examples of amino alcohol compounds include aminoethanol, 3-amino-1-propanol, 2- (2-aminoethoxy) ethanol, 2-amino-1,3-propanediol, and 2-amino-2-methyl-1,3. -Propanediol, 1,3-diamino-2-propanol, etc. can be mentioned.

  When forming a polymer having both a urea bond and a urethane bond, for example, the amino alcohol compound is reacted with the polyisocyanate compound, or both the polyamine compound and the polyol compound are reacted. Can be obtained.

Component A preferably further has an acidic group. By having an acidic group, the developability is excellent.
The acidic group in component A is preferably at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, an active imide group, a carboxylic acid group, a phosphoric acid group and a sulfonic acid group. It is more preferably at least one group selected from the group consisting of a hydrophilic hydroxyl group, a sulfonamide group and a carboxylic acid group, and even more preferably a phenolic hydroxyl group.
The active imide group in the present invention is a group in which two carbonyl groups are bonded to a nitrogen atom, and is an acidic group that can generate a carboxylic acid group in equilibrium due to water in the developer during development, moisture in the layer, or the like. is there.
The acidic group may have either the main chain or the side chain of the polymer, or both the main chain and the side chain, but the acidic group in Component A is an acidic group directly bonded to the main chain. It is preferable.
The method for introducing an acidic group into Component A is not particularly limited, and can be obtained by reacting the polyisocyanate compound with a polyamine compound having an acidic group or a polyol compound having an acidic group. It may be introduced after polycondensation by molecular reaction.

  Component A preferably has a structural unit represented by the following formula AF-1 as a structural unit having a phenolic hydroxyl group in the main chain.

In formula AF-1, R ^A1 represents a single bond or a divalent linking group.
R ^A1 is preferably a single bond, an alkylene group having 1 to 6 carbon atoms or a sulfonyl group, more preferably a single bond or an alkylene group having 1 to 5 carbon atoms, and a single bond or a methylene group. More preferably, it is a single bond.
The alkylene group in R ^A1 may be linear, branched or cyclic. The alkylene group in R ^A1 may be substituted, and preferred examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an aryl group, and a halogen atom. The aryl group may be further substituted, and a preferable substituent is a hydroxy group.
Moreover, it is preferable that the phenolic hydroxyl group in Formula AF-1 is couple | bonded with the ortho position of the position which -NH- couple | bonded. In the above embodiment, a lithographic printing plate precursor excellent in developability can be obtained.
Preferred examples of the diamine compound that forms the structural unit represented by Formula AF-1 include the following compounds.

  Among the diamine compounds, DADHB, 1,3-DAP, DAMDH, PDABP, AHPPHFP or AHPFL are preferable, and DADHB is more preferable.

  Component A preferably has a structural unit represented by the following formula AF-2 as a structural unit having a sulfonamide group in the main chain.

In formula AF-2, R ^A2 , R ^A3 and R ^A4 each independently represent a divalent linking group.
R ^A2 and R ^A4 are each independently preferably an alkylene group or an arylene group, more preferably an alkylene group having 1 to 4 carbon atoms or an arylene group having 6 to 10 carbon atoms, and a phenylene group. Is more preferable.
R ^A2 and R ^A4 are preferably both an arylene group, and more preferably a phenylene group.
The arylene group or alkylene group in R ^A2 and R ^A4 may be substituted, and the substituent is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom. An alkyl group of ˜4 is more preferred.
R ^A3 is preferably an arylene group, —R ^A5 —O—R ^A6 —, or —R ^A5 —SO ₂ —R ^A6 —, more preferably an arylene group, and preferably a phenylene group. Further preferred. R ^A5 and R ^A6 each independently represent an arylene group, preferably a phenylene group.
The arylene group in R ^A3 may be substituted, and the substituent is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and an alkyl group having 1 to 4 carbon atoms. More preferred.
Preferred examples of the diamine compound that forms the structural unit represented by Formula AF-2 include the following compounds.

  Component A preferably has a structural unit represented by the following formula AF-3 as a structural unit having a sulfonamide group in the main chain.

In formula AF-3, R ^A7 , R ^A8 and R ^A9 each independently represent a divalent linking group.
R ^A7 and R ^A9 are each independently preferably an alkylene group or an arylene group, more preferably an alkylene group having 2 to 6 carbon atoms or an arylene group having 6 to 10 carbon atoms, and 2 to 4 carbon atoms. More preferably, it is an alkylene group.
R ^A7 and R ^A9 are preferably both alkylene groups, more preferably ethylene groups.
The arylene group or alkylene group in R ^A7 and R ^A9 may be substituted, and the substituent is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom. An alkyl group of ˜4 is more preferred.
R ^A8 is preferably an arylene group, —R ^A10 —O—R ^A11 —, or —R ^A10 —SO ₂ —R ^A11 —, more preferably an arylene group, and preferably a phenylene group. Further preferred. R ^A10 and R ^A11 each independently represent an arylene group, preferably a phenylene group.
The arylene group in R ^A8 may be substituted. The substituent is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and an alkyl group having 1 to 4 carbon atoms. More preferred.
Preferred examples of the diol compound that forms the structural unit represented by the formula AF-3 include the following compounds.

  Moreover, there is no restriction | limiting in particular as a compound which introduce | transduces a carboxylic acid group into the component A, For example, compounds, such as diaminobenzoic acid and 2-carboxy piperazine, are mentioned, Moreover, a polyol compound is mentioned in the compound which has the following acid anhydride groups. May be reacted.

  The weight average molecular weight of Component A is preferably 1,000 or more, more preferably 5,000 to 300,000, still more preferably 10,000 to 200,000, and more preferably 30,000 to Particularly preferred is 100,000. Within the above range, the lithographic printing plate obtained is more excellent in printing durability and chemical resistance.

Component A may be contained singly or in combination of two or more.
The content of Component A in the image recording layer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and more preferably 40 to 70% with respect to the total mass of the image recording layer. More preferably, it is mass%. When it is within the above range, the pattern formability upon development is good, and the lithographic printing plate obtained is more excellent in printing durability and chemical resistance.

Component B: Infrared Absorbing Material The image recording layer contains an infrared absorbing material (also simply referred to as “component B”) as component B.
The infrared absorbing material is not particularly limited as long as it is a dye that absorbs infrared light and generates heat, and various dyes known as infrared absorbing materials can be used.
As the infrared absorbing material that can be used in the present invention, commercially available dyes and known materials described in literature (for example, “Dye Handbook” edited by Organic Synthetic Chemistry Association, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb at least infrared light or near-infrared light are preferable because they are suitable for use in lasers that emit infrared light or near-infrared light, and cyanine dyes are particularly preferred. preferable.

  Examples of the dye that absorbs at least infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-. Cyanine dyes described in each publication such as 78787, methine dyes described in each publication such as JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, Japanese Laid-Open Patent Publication Nos. 58-112793, 58-224793, 59-48187, 59-73996, 60-52940, 60-63744, etc. Naphthoquinone dyes described in JP-A-58-112792, squarylium dyes described in JP-A-58-112792, cyanine dyes described in British Patent 434,875, etc. Can.

Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzoates described in US Pat. No. 3,881,924 are also preferred. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (U.S. Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-2220143, 59-41363, 59-84248, 59-84249, 59-146063, 59-146061, and pyrium compounds described in JP-A-59-216146. Cyanine dyes, pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, etc., and Japanese Patent Publication Nos. 5-13514 and 5-19702 Pyrylium compounds disclosed in distribution is, as commercially available products, Epolight III-178 of Eporin Co., Epolight III-130, Epolight III-125 and the like are particularly preferably used.
Another particularly preferable example of the dye includes near infrared absorbing dyes described as formulas I and II in US Pat. No. 4,756,993.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the cyanine dye represented by the following formula a is most preferable because it gives high polymerization activity and is excellent in stability and economy when used in the upper layer in the present invention.

In formula a, X ¹ represents a hydrogen atom, a halogen atom, a diarylamino group (—NPh ₂ ), X ² -L ² or a group shown below. X ² represents an oxygen atom or a sulfur atom. L ² represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. Here, the hetero atom represents N, S, O, a halogen atom, or Se.

In the above formulas, 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 substitution, selected from the group consisting of substituted or unsubstituted amino group and a halogen atom Represents a group.

R ²¹ and R ²² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive layer coating solution, R ²¹ and R ²² are preferably a hydrocarbon group having 2 to 12 carbon atoms, and R ²¹ and R ²² are bonded to each other to form a 5-membered ring or 6 It is particularly preferable that a member 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 C1-C12 hydrocarbon group, a halogen atom, and a C1-C12 alkoxy group are mentioned.
Y ¹¹ and Y ¹² may be the same or different and each represents a sulfur atom or a C 3-12 dialkylmethylene group. R ²³ and R ²⁴ may be the same or different and each represents a C 1-20 hydrocarbon group which may have a substituent. Preferable substituents include an alkoxy group having 1 to 12 carbon atoms, a carboxyl group, and a sulfo group.
R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Further, _{Z a} ^- represents a counter anion. However, when the cyanine dye represented by the formula a has an anionic substituent in the structure and neutralization of charge is not necessary, Z _a ⁻ is not necessary. Preferred Z _a ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably perchloric acid, from the storage stability of the photosensitive layer coating solution. Ions, hexafluorophosphate ions, and aryl sulfonate ions.

Specific examples of the cyanine dye represented by formula a that can be suitably used include paragraphs 0017 to 0019 of JP-A No. 2001-133969, paragraphs 0012 to 0038 of JP-A No. 2002-40638, and JP-A No. 2002-23360. And those described in paragraphs [0012] to [0023] of the publication.
Particularly preferred as the infrared absorbing material contained in the upper layer is the cyanine dye A shown below.

  The content of the infrared absorbing material in the image recording layer is preferably 0.01 to 50% by mass, more preferably 0.1 to 30% by mass, based on the total mass of the image recording layer. 1.0 to 30% by mass is particularly preferable. When the addition amount is 0.01% by mass or more, high sensitivity is obtained, and when it is 50% by mass or less, the uniformity of the layer is good and the durability of the layer is excellent.

Component C: Compound Having Blocked Isocyanate Group The image recording layer contains, as Component C, a compound having a blocked isocyanate group (also simply referred to as “Component C”).
In the present invention, the blocked isocyanate group is a protective group obtained by reacting a compound having a hydrogen atom capable of reacting with an isocyanate group (usually called a blocking agent) to protect the isocyanate group. The introduced protecting group is a hydrogen atom removed from the blocking agent and is usually called a blocking group. For example, in the structure represented by A′—C (═O) —NH—, A ′ is a protecting group.

As the blocking agent used in the present invention, for example, the blocking agent described in paragraph 0009 of JP-A-5-186564, the blocking agent described in paragraph 0022 of JP-A-2002-275231 can be used, These contents are incorporated herein.
Specifically, compounds having a phenolic hydroxyl group such as phenol, naphthol, cresol, xylenol, halogen-substituted phenol; oxime compounds such as acetoxime, formaldoxime, cyclohexaneoxime, methylethylketoxime; pyrazole, methylpyrazole, dimethylpyrazole, etc. Compounds having a pyrazole structure; aliphatic alcohol compounds such as methanol, ethanol, propanol, butanol, cyclohexanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, and alkyl lactate; activities such as ethyl acetoacetate, diethyl malonate, and acetylacetone Compound having methylene structure; mercaptan compound such as alkyl mercaptan and aryl mercaptan; α-lactam, β -Lactam compounds, such as lactam, (gamma) -lactam, (delta) -lactam, an imide compound, an imidazole compound, a primary amine compound, a secondary amine compound, etc. are mentioned.

Examples of the blocked isocyanate group include a compound having a phenolic hydroxyl group, an oxime compound, a compound having a pyrazole structure, an aliphatic alcohol compound, a compound having an active methylene structure, a mercaptan compound, a lactam compound, an imide compound, an imidazole compound, first It is preferably a blocked isocyanate group in which an isocyanate group is protected by a compound selected from the group consisting of a secondary amine compound and a secondary amine compound, a compound having a phenolic hydroxyl group, an oxime compound, and an aliphatic group More preferably, it is a blocked isocyanate group in which an isocyanate group is protected by a compound selected from the group consisting of alcohol compounds, and a compound selected from the group consisting of oxime compounds and aliphatic alcohol compounds. More preferably an isocyanate group is protected blocked isocyanate groups Ri, it is particularly preferred by an oxime compound isocyanate group is a protected blocked isocyanate groups. In the above embodiment, the thermal decomposability at the time of burning is excellent, and even when the burning treatment is performed, the printing durability and chemical resistance are excellent.
Further, the blocked isocyanate group is preferably a group represented by the following formula C-1.

In formula C-1, Z represents a monovalent organic group.
Z is preferably a group that can be eliminated by heating. Here, the group that is eliminated by heating refers to a group that is eliminated when heated at 90 to 250 ° C., for example.
As Z, a compound having a phenolic hydroxyl group, an oxime compound, a compound having a pyrazole structure, an aliphatic alcohol compound, a compound having an active methylene structure, a mercaptan compound, a lactam compound, an imide compound, an imidazole compound, a primary amine It is preferably a group obtained by removing one active hydrogen from a compound selected from the group consisting of a compound and a secondary amine compound, a compound having a phenolic hydroxyl group, an oxime compound, a compound having a pyrazole structure, and a lactam compound And more preferably a group obtained by removing one active hydrogen from a compound selected from the group consisting of aliphatic alcohol compounds, active from a compound selected from the group consisting of oxime compounds and aliphatic alcohol compounds. It is even more preferred that it is a group without one hydrogen. Ku, and particularly preferably a group formed by removing a hydrogen atom of the = N-OH is in the active hydrogen from an oxime compound.
Moreover, it is preferable that it is 1-40, as for carbon number of Z, it is more preferable that it is 1-20, it is still more preferable that it is 2-12, and it is especially preferable that it is 3-8.
Furthermore, Z is preferably a group bonded to the carbon atom of the carbonyl group in Formula C-1 by a hetero atom, and more preferably a group bonded to the carbon atom of the carbonyl group in Formula C-1 by an oxygen atom. preferable.
The blocked isocyanate group is more preferably a group represented by the following formula C-1-1.

In formula C-1-1, R ^OX1 and R ^OX2 each independently represent a hydrogen atom, an alkyl group, or an aryl group.
R ^OX1 and R ^OX2 are each independently preferably an alkyl group or an aryl group, more preferably an alkyl group, and particularly preferably a methyl group or an ethyl group.
R ^OX1 and R ^OX2 may be bonded to each other to form a ring.
Moreover, it is preferable that carbon number of ^ROX1 and ^ROX2 is respectively independently 1-20, It is more preferable that it is 1-12, It is further more preferable that it is 1-6, It is 1 or 2 Is particularly preferred.

  The compound having a blocked isocyanate group used in the present invention may be a polymer as long as it has one blocked isocyanate group in one molecule, and two or more blocked isocyanate groups in one molecule. It is preferable that it has 3 or more blocked isocyanate groups in one molecule, and a polymer having a blocked isocyanate group in the side chain is particularly preferable.

<Polymer having blocked isocyanate group>
The polymer having a blocked isocyanate group used in the present invention is preferably an acrylic resin, a polystyrene resin, or a copolymer thereof, and a polymer having a structural unit represented by the following formula C-2-0 It is more preferable that

In formula C-2-0, R ^C1 represents a hydrogen atom or a methyl group, W represents a divalent linking group, and Z represents a monovalent organic group.
In formula C-2-0, W represents a divalent linking group.
Examples of the divalent linking group include a linear, branched or cyclic alkylene group, an arylene group, -O-, -COO-, -S-, -NR-, -CO-, -NRCO-, -SO. Examples thereof include a divalent group such as _2- or a combination of these groups. Here, R represents a hydrogen atom or a C1-C4 alkyl group, and a hydrogen atom is preferable.
Examples of the divalent linking _{group, - (CH 2) m -} (. M represents an integer of 1 to 10, preferably an integer of 1 to 6, more preferably an integer of 1 to 4), 5 carbon atoms A cyclic alkylene group having 10 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, or these groups and at least one group of -O-, -COO-, -S-, -NH- and -CO-. Groups consisting of combinations are preferred.
Z in formula C-2-0 has the same meaning as Z in formula C-1, and the preferred embodiment is also the same.
The polymer having a blocked isocyanate group more preferably has a structural unit represented by the following formula C-2.

In Formula C-2, R ^C1 represents a hydrogen atom or a methyl group, X and Y each independently represent a divalent linking group or a single bond, and Z represents a monovalent organic group.

In formula C-2, X is preferably an arylene group or —C (═O) —, and more preferably —C (═O) —. When X is an arylene group, a phenylene group is preferable.
In formula C-2, Y represents a divalent linking group.
Examples of the divalent linking group include a linear, branched or cyclic alkylene group, —O—, —COO—, —S—, —NR—, —CO—, —NRCO—, —SO ₂ — and the like. And those consisting of a combination of these groups. Here, R represents a hydrogen atom or a C1-C4 alkyl group, and a hydrogen atom is preferable.
Examples of the divalent linking _{group, - (CH 2) m -} (. M represents an integer of 1 to 10, preferably an integer of 1 to 6, more preferably an integer of 1 to 4), 5 carbon atoms 10 to 10 cyclic alkylene groups, or a group composed of a combination of these groups with at least one of —O—, —COO—, —S—, —NH— and —CO—, is preferable. CH ₂ ) _m — (m represents an integer of 1 to 4) is particularly preferable.
Z in Formula C-2 has the same meaning as Z in Formula C-1, and the preferred embodiment is also the same.
More preferably, the polymer having a blocked isocyanate group has a structural unit represented by the following formula C-2-1.

In formula C-2-1, R ^C1 represents a hydrogen atom or a methyl group, Y represents a divalent linking group or a single bond, and Z represents a monovalent organic group.

Y and Z in formula C-2-1 have the same meanings as Y and Z in formula C-1, and the preferred embodiments are also the same.
Specific examples of the structural unit having a blocked isocyanate group are listed below, but the present invention is not limited to these. In the following specific examples, R ^x represents a hydrogen atom or a methyl group, and a structural unit represented by the following formula BU-1 or formula BU-2 is preferable.

The polymer having a blocked isocyanate group preferably further has an acidic group. By having an acidic group, the developability is excellent.
The acidic group in Component C is preferably at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, an active imide group, a carboxylic acid group, a phosphoric acid group and a sulfonic acid group. It is more preferably at least one group selected from the group consisting of a functional hydroxyl group, a sulfonamide group, and a carboxylic acid group, and more preferably a sulfonamide group and / or a carboxylic acid group.
The acidic group in component C may be present in either the main chain or the side chain of the polymer, or in both the main chain and the side chain.
The method for introducing an acidic group into the polymer having a blocked isocyanate group is not particularly limited, and an ethylenically unsaturated compound having a carboxy group may be copolymerized or after polycondensation by a polymer reaction. It may be introduced.
Especially, it is preferable that the polymer which has the said blocked isocyanate group has a structural unit derived from (meth) acrylic acid.

-Preferred embodiment of polymer having blocked isocyanate group-
In the polymer having a blocked isocyanate group, the constituent unit having a blocked isocyanate group is preferably 1 mol% or more, more preferably 10 mol% or more, and still more preferably 50 mol% or more. When it is in the above range, the printing durability and chemical resistance after the burning treatment are improved. In the present invention, when the content of the “structural unit” is defined in terms of molar ratio, the “structural unit” is synonymous with the “monomer unit”. In the present invention, the “monomer unit” may be modified after polymerization by a polymer reaction or the like. The same applies to the following.
The polymer having a blocked isocyanate group preferably has a weight average molecular weight of 1,000 or more, and more preferably 5,000 or more. The upper limit of the weight average molecular weight is not particularly limited, but is preferably 50,000 or less, and more preferably 30,000 or less.
By setting the weight average molecular weight to 5,000 or more, it is presumed that the molecular weight of the crosslinked structure after the burning treatment is improved, and the improvement in printing durability and chemical resistance is effectively exhibited. Further, when the molecular weight is 30,000 or less, the developability and development residue dispersibility are excellent.

<Compound having a blocked isocyanate group and a molecular weight of less than 1,000>
In the present invention, a polymer having a blocked isocyanate group is preferably used, but a compound having a blocked isocyanate group and having a molecular weight of less than 1,000 can also be suitably used.
The compound having a blocked isocyanate group and a molecular weight of less than 1,000 is not particularly limited as long as it has a blocked isocyanate group, but preferably has two or more blocked isocyanate groups in one molecule. More preferably, it has three or more blocked isocyanate groups.
Preferred examples of the compound having a blocked isocyanate group and having a molecular weight of less than 1,000 include compounds represented by the following formula C-3 or formula C-4.

In formula C-3, L ^C each independently represents a divalent organic group having 1 to 30 carbon atoms.

L ^C may be branched, may be an unsaturated bond, and may have an aromatic ring and / or an aliphatic ring cyclic structure. Further, some of the atoms constituting the cyclic structure may be an oxygen atom, a sulfur atom, or a nitrogen atom. Furthermore, the organic group or the substituent that the organic group has may be substituted with a group containing an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, a boron atom, or a halogen atom, and these substituents form a bond with each other. You may do it.
The three L ^{C in} formula C-3 may be the same or different.
L ^C in Formula C-3 is preferably a divalent hydrocarbon group having 1 to 20 carbon atoms, and more preferably a divalent hydrocarbon group having 3 to 15 carbon atoms.
The molecular weight of the compound represented by Formula C-3 is preferably 700 or more and less than 1,000.
Specific examples of L ^C include an alkylene group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an arylene group, a carbonyl group, and a group obtained by combining these. Further, when ^{L C} contains the aforementioned groups, ether structure (-O-), thioether structures (-S-) may have been combined. L ^C is preferably an alkylene group, a cycloalkyl group, an arylene group, a carbonyl group, or a group obtained by combining these, and particularly has a structure represented by the following formula C-3-1 or C-3-2. preferable.

In the formula, R ^N1 represents a bonding position with the isocyanurate mother nucleus, R ^N2 represents a bonding position with the blocked isocyanate group, m represents an integer of 3 to 9, and n represents an integer of 1 to 6. .

  Specific examples of the compound represented by the formula C-3 include Death Module BL4265SN, Death Module BL3575 / 1 MPA / SN, Death Module BL3272 MPA (all manufactured by Sumika Bayer Urethane Co., Ltd.), Duranate TPA-B80E. (Asahi Kasei Chemicals Co., Ltd.).

In formula C-4, L ^C each independently represents a divalent organic group having 1 to 20 carbon atoms.

L ^C in Formula C-4 is synonymous with L ^C in Formula C-3, except for the following, and the preferred embodiments are also the same.
L ^C in Formula C-4 is preferably a divalent hydrocarbon group having 1 to 12 carbon atoms, and more preferably a divalent hydrocarbon group having 3 to 9 carbon atoms.
The molecular weight of the compound represented by Formula C-4 is preferably 600 to 900.

  Specific examples of the compound represented by the formula C-4 include Duranate 17B-60P and Duranate 17B-60PX (both manufactured by Asahi Kasei Chemicals Corporation).

The compounding amount of the compound having a blocked isocyanate group in the image recording layer is preferably 1 to 50% by mass, more preferably 5 to 30% by mass with respect to the total mass of the image recording layer. .
The compounding amount of the compound having a blocked isocyanate group in the image recording layer is preferably 1 to 50% by mass, and preferably 10 to 30% by mass, based on the total mass of component A in the image recording layer. It is more preferable that
Moreover, the compound which has a blocked isocyanate group may be used not only individually by 1 type but in combination of 2 or more types.

The photosensitive resin composition of the present invention may contain other components as desired as long as the effects of the present invention are not impaired.
Hereinafter, other alkali-soluble resins, acid generators, acid multipliers, and other additives, which are optional components of the photosensitive resin composition of the present invention, will be described.

Component D: Phenol Resin In the present invention, the image recording layer preferably contains a phenol resin (also simply referred to as “component D”) as component D together with component A, and phenol or substituted phenols as a structural unit. More preferably, it is a phenolic resin containing novolak resin.
The novolak resin is an alkali-soluble resin that is preferably used for the image recording layer in the invention from the viewpoint that strong hydrogen bonding occurs in the unexposed area and that some hydrogen bonds are easily released in the exposed area.
The novolak resin is not particularly limited as long as it contains phenols as a structural unit in the molecule.

The novolak resin in the present invention is a resin obtained by a condensation reaction of phenol, a substituted phenol shown below and an aldehyde. Specifically, the phenols include phenol, isopropylphenol, t-butylphenol, Examples thereof include t-amylphenol, hexylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isopropylcresol, t-butylcresol, and t-amylresole. T-butylphenol and t-butylcresol are preferred.
Examples of aldehydes include aliphatic and aromatic aldehydes such as formaldehyde, acetaldehyde, acrolein, and crotonaldehyde. Preferred are formaldehyde and acetaldehyde.
More specifically, the novolak resin in the present invention includes, for example, a condensation polymer of phenol and formaldehyde (phenol formaldehyde resin), a condensation polymer of m-cresol and formaldehyde (m-cresol formaldehyde resin), p. -Condensation polymer of cresol and formaldehyde (p-cresol formaldehyde resin), m- / p-mixed cresol and formaldehyde (m- / p-mixed cresol formaldehyde resin), phenol and cresol (m-, Any of p- or m- / p-mixed) and a condensation polymer of formaldehyde (phenol / cresol (may be any of m-, p- or m- / p-mixed) mixed formaldehyde resin), etc. Is mentioned.
Further, as the novolak resin, as described in U.S. Pat. No. 4,123,279, an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. Examples thereof include a condensation polymer of phenol and formaldehyde as a substituent.
Among these novolak resins, phenol formaldehyde resins and phenol / cresol mixed formaldehyde resins are particularly preferable.

The weight average molecular weight of the phenol resin is preferably 500 to 50,000, more preferably 700 to 20,000, and particularly preferably 1,000 to 10,000. Further, the dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
Only 1 type may be used for such a phenol resin, and 2 or more types may be mixed and used for it.
The addition amount of the phenol resin in the image recording layer in the present invention is 1 to 90 as the content ratio (mass ratio) of the phenol resin with respect to 100 parts by mass of the component A from the viewpoints of burning suitability and image formability. Part by mass is preferable, 5 to 50 parts by mass is more preferable, and 10 to 30 parts by mass is particularly preferable.

<Acid generator>
The image recording layer preferably contains an acid generator from the viewpoint of improving sensitivity.
In this invention, an acid generator is a compound which generate | occur | produces an acid with light or a heat | fever, and points out the compound which decomposes | disassembles and generate | occur | produces an acid by infrared irradiation or a heating of 100 degreeC or more. The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid. The acid generated from the acid generator functions as a catalyst, the chemical bond in the acid-decomposable group is cleaved to become an acid group, and the solubility of the image recording layer in an alkaline aqueous solution is further improved.

Examples of the acid generator suitably used in the present invention include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and diazonium salts. Specific examples include compounds described in US Pat. No. 4,708,925 and JP-A-7-20629. In particular, iodonium salts, sulfonium salts, and diazonium salts having a sulfonate ion as a counter ion are preferable. Examples of the diazonium salt include a diazonium compound described in U.S. Pat. No. 3,867,147, a diazonium compound described in U.S. Pat. No. 2,632,703, and JP-A-1-102456 and JP-A-1-102457. The diazo resin described in each of the above publications is also preferred. Also preferred are benzyl sulfonates described in US Pat. Nos. 5,135,838 and 5,200,544. Furthermore, active sulfonic acid esters and disulfonyl compounds described in JP-A-2-100054, JP-A-2-100055 and JP-A-9-197671 are also preferred. In addition, haloalkyl-substituted S-triazines described in JP-A-7-271029 are also preferable.
Furthermore, the compound described as “acid precursor” in the above-mentioned JP-A-8-220552, or “(a) a compound capable of generating an acid upon irradiation with actinic rays” in JP-A-9-171254. Can be applied as the acid generator of the present invention.
Among these, from the viewpoint of sensitivity and stability, it is preferable to use an onium salt compound as the acid generator. Hereinafter, the onium salt compound will be described.

Examples of the onium salt compound that can be suitably used in the present invention include compounds known as compounds that generate an acid upon decomposition by thermal energy generated from an infrared absorber by infrared exposure and exposure. Examples of the onium salt compound suitable for the present invention include known thermal polymerization initiators and compounds having an onium salt structure described below having a bond with small bond dissociation energy from the viewpoint of sensitivity.
Examples of the onium salt suitably used in the present invention include known diazonium salts, iodonium salts, sulfonium salts, ammonium salts, pyridinium salts, azinium salts, and the like. Among them, triarylsulfonium or diaryliodonium sulfonate , Carboxylate, BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ^{— and the} like are preferable.
As an onium salt that can be used as an acid generator in the present invention, an onium salt described as an example of a radical polymerization initiator in paragraphs 0031 to 0056 of JP-A-2008-195018 is used as the acid generator in the present invention. Can be suitably used. These compounds easily generate an acid when decomposed by the thermal energy generated from the infrared absorber.
In addition, N—O bonds described in JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363 are disclosed. A group of compounds having the above is also suitably used as the acid generator in the present invention.
More preferable examples of the acid generator that can be used in the present invention include the following compounds PAG-1 to PAG-5. Me represents a methyl group.

When these acid generators are contained in the image recording layer, these compounds may be used alone or in combination of two or more.
The addition amount of the acid generator in the image recording layer is preferably 0.01 to 50% by mass, more preferably 0.1 to 40% by mass with respect to the total mass of the image recording layer. More preferably, it is 0.5-30 mass%. When the addition amount is in the above range, an improvement in sensitivity, which is an effect of adding an acid generator, is observed, and generation of a residual film in a non-image area is suppressed.

<Acid multiplication agent>
An acid proliferation agent may be added to the image recording layer.
The acid proliferating agent in the present invention is a compound substituted with a relatively strong acid residue, and is a compound that is easily eliminated in the presence of an acid catalyst to newly generate an acid. That is, it decomposes by an acid catalytic reaction and generates an acid again. One or more acids are increased in one reaction, and the sensitivity is dramatically improved by increasing the acid concentration at an accelerated rate as the reaction proceeds. The strength of the acid generated is preferably 3 or less, more preferably 2 or less, as an acid dissociation constant (pKa). Within the above range, the elimination reaction by the acid catalyst can be easily caused.
Examples of the acid used for such an acid catalyst include dichloroacetic acid, trichloroacetic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and phenylsulfonic acid.

Examples of the acid proliferating agent include International Publication No. 95/29968, International Publication No. 98/24000, JP-A-8-305262, JP-A-9-34106, JP-A-8-248561, JP-A-8-503082, US Pat. No. 5,445,917, JP-T-8-503081, US Pat. No. 5,534,393, US Pat. No. 5,395,736, US Pat. No. 5,741,630, US Pat. No. 5,334,489, US Pat. No. 5,582,956, US Pat. No. 5,578,424, US Pat. No. 5,453,345, US Pat. No. 5,445,917, European patent Nos. 665,960, 757,628, 665,961, U.S. Pat. No. 5,667,943, and JP-A-10-1598.
Moreover, an acid growth agent can be used 1 type or in combination of 2 or more types.

  Preferable specific examples of the acid proliferating agent in the present invention include compounds described in paragraphs 0056 to 0067 of JP-A No. 2001-66765. Among these, the following compounds described as exemplary compounds (ADD-1), (ADD-2), and (ADD-3) can be preferably used.

  The addition amount of these acid proliferating agents is preferably 0.01 to 20% by mass, more preferably 0.01 to 10% by mass, and preferably 0. 0% by mass relative to the total mass of the image recording layer. More preferably, it is 1-5 mass%. When the addition amount of the acid proliferating agent is within the above range, the effect of adding the acid proliferating agent is sufficiently obtained, sensitivity is improved, and a decrease in the film strength of the image area is suppressed.

<Other additives>
The image recording layer may contain, as other additives, a development accelerator, a surfactant, a printout / coloring agent, a plasticizer, a wax agent, and the like.

-Development accelerator-
A development accelerator such as acid anhydrides, phenols, and organic acids may be added to the image recording layer for the purpose of improving sensitivity.
As the acid anhydrides, cyclic acid anhydrides are preferable. Specific examples of the cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, and hexahydro anhydride described in US Pat. No. 4,115,128. Phthalic acid, 3,6-endooxytetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of acyclic acid anhydrides include acetic anhydride.
Examples of phenols include bisphenol A, 2,2′-bishydroxysulfone, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4- Examples include hydroxybenzophenone, 4,4 ′, 4 ″ -trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane. .
Examples of the organic acids are described in JP-A-60-88942, JP-A-2-96755, and the like. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, Ethyl sulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene Examples include -1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like.
The content of the acid anhydride, phenols and organic acids in the image recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass with respect to the total mass of the image recording layer. Preferably, 0.1-10 mass% is especially preferable.

-Surfactant-
The image recording layer may contain a surfactant in order to improve the coating property at the time of forming the layer and to expand the stability of the processing with respect to the developing conditions.
Examples of the surfactant include nonionic surfactants such as those described in JP-A-62-251740 and JP-A-3-208514, JP-A-59-121044, and JP-A-4- Amphoteric surfactants as described in JP-A-13149, fluorine-containing monomers as described in JP-A-62-170950, JP-A-11-288093, JP-A-2003-57820 A copolymer can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.
Specific examples of amphoteric activators include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
The content of the surfactant in the image recording layer is preferably from 0.01 to 15% by mass, more preferably from 0.01 to 5% by mass, based on the total mass of the image recording layer. 0% by mass is more preferable.

-Print-out agent / colorant-
A print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added to the image recording layer.
Examples of the print-out agent and the colorant are described in detail in paragraphs 0122 to 0123 of JP-A-2009-229917, and the compounds described herein can be applied to the present invention.
The content of these print-out agent and colorant in the image recording layer is preferably added in a proportion of 0.01 to 10% by mass, based on the total mass of the image recording layer. It is more preferable to add at a ratio of%.

-Plasticizer-
A plasticizer may be added to the image recording layer in order to impart flexibility and the like of the coating film.
For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.
These plasticizers in the image recording layer are preferably added at a rate of 0.5 to 10% by mass, and added at a rate of 1.0 to 5% by mass with respect to the total mass of the image recording layer. Is more preferable.

-Wax agent-
In the image recording layer, for the purpose of imparting scratch resistance, a compound that lowers the static friction coefficient of the surface, for example, a wax agent may be added. Specifically, as described in US Pat. No. 6,117,913, JP-A No. 2003-149799, JP-A No. 2003-302750, or JP-A No. 2004-12770, A compound having an ester of a long-chain alkyl carboxylic acid can be exemplified.
The content of the wax agent in the image recording layer is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass with respect to the total mass of the image recording layer.

<Preferred composition ratio of each component>
In the image recording layer, the content of the component A is preferably 10 to 90% by mass and the content of the infrared absorbing material is 0.01 to 50% by mass with respect to the total mass of the image recording layer. Preferably, the content of the compound having a blocked isocyanate group is preferably 1 to 50% by mass, the content of the phenol resin is preferably 0 to 50% by mass, and the content of the acid generator is It is preferably 0 to 30% by mass, the content of the acid proliferating agent is preferably 0 to 20% by mass, the content of the development accelerator is preferably 0 to 20% by mass, and the surfactant The content of is preferably 0 to 5% by mass, the content of the baking agent / colorant is preferably 0 to 10% by mass, and the content of the plasticizer is 0 to 10% by mass. Preferably, wax agent The content is preferably 0 to 10 mass%.

<Solvent>
The image recording layer used in the present invention can be formed by dissolving each of the above components in a solvent, coating the solution on a suitable support, and drying as necessary.
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 Ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, 1,3-dimethyl-2- Although imidazolidinone etc. can be mentioned, it is not limited to this. These solvents are used alone or in combination.

<Formation of lower layer and upper layer>
The image recording layer in the present invention is preferably an image recording layer in which a lower layer and an upper layer are disposed in this order on a support (hereinafter also referred to as “two-layer planographic printing plate precursor”).
More specifically, in the positive planographic printing plate precursor of the present invention, the image recording layer is composed of a lower layer and an upper layer, and the image recording layer containing component A to component C is at least any one of the lower layer and the upper layer. The image recording layer containing component A to component C is more preferably at least the lower layer, the lower layer is the image recording layer containing component A to component C, and the upper layer. Is more preferably other image recording layer not containing at least one of component A to component C.
In principle, the lower layer and the upper layer are preferably formed by separating the two layers.
As a method for forming the two layers separately, for example, as described in paragraphs 0068 to 0069 of JP2011-209343A, a solvent of a component contained in the lower layer and a component contained in the upper layer Examples thereof include a method utilizing the difference in solubility, or a method of rapidly drying and removing the solvent after applying the upper layer. Use of the latter method in combination is preferable because separation between layers can be performed more satisfactorily.

  The content of the component A contained in the upper layer and / or the lower layer is preferably 10 to 100% by mass, and 50 to 98% by mass with respect to the total mass of the upper layer and / or the lower layer in which the component A is contained. It is more preferable, and it is still more preferable that it is 60-95 mass%. When the content is within this range, the pattern formability upon development is good.

The coating amount after drying of the lower layer component coated on the support of the lithographic printing plate precursor according to the present invention is preferably in the range of 0.5 to 4.0 g / m ² , 0.6 to 2.5 g. / M ² is more preferable. When it is 0.5 g / m ² or more, printing durability is excellent, and when it is 4.0 g / m ² or less, image reproducibility and sensitivity are excellent.
Moreover, it is preferable that it is the range of 0.05-1.0 g / m < ² >, and, as for the application quantity after drying of an upper layer component, it is more preferable that it is the range of 0.08-0.7 g / m < ² >. If it is 0.05 g / ^{m 2} or more, development latitude, and excellent scratch resistance, if it is 1.0 g / ^{m 2} or less, excellent sensitivity.
The lower layer and the coating amount after drying of the combined upper layer, preferably in the range of 0.6~4.0g / ^{m 2,} more preferably in the range of 0.7 to 2.5 g / ^{m 2} . When it is 0.6 g / m ² or more, printing durability is excellent, and when it is 4.0 g / m ² or less, image reproducibility and sensitivity are excellent.

<Upper layer>
The upper layer of the lithographic printing plate precursor having a two-layer structure in the present invention may be the image forming layer containing Component A to Component C, or other image recording not containing at least one of Component A to Component C. Although it may be a layer, it is preferably another image recording layer that does not contain at least one of component A to component C.
The upper layer of the lithographic printing plate precursor having a two-layer structure in the present invention is preferably an infrared-sensitive positive recording layer whose solubility in an alkaline aqueous solution is improved by heat.
There is no particular limitation on the mechanism for improving the solubility in an aqueous alkali solution by heat in the upper layer, and any mechanism can be used as long as it includes a binder resin and improves the solubility of the heated region. As heat utilized for image formation, heat generated when a lower layer containing an infrared absorber is exposed can be used.
The upper layer whose solubility in an alkaline aqueous solution is improved by heat includes, for example, a layer containing an alkali-soluble resin having a hydrogen bonding ability such as novolak and urethane, a water-insoluble and alkali-soluble resin, and a compound having a dissolution inhibiting action. Preferred examples include a layer and a layer containing a compound capable of ablation.

  Further, by adding an infrared absorbing material to the upper layer, the heat generated in the upper layer can also be used for image formation. Examples of the structure of the upper layer containing the infrared absorbing material include, for example, a layer containing the infrared absorbing material, a water-insoluble and alkali-soluble resin, and a compound having a dissolution inhibiting action, an infrared absorbing material, a water-insoluble and alkali-soluble resin, and an acid generator. A layer containing is preferred.

-Water-insoluble and alkali-soluble resin-
The upper layer in the present invention preferably contains a water-insoluble and alkali-soluble resin. By containing the water-insoluble and alkali-soluble resin, an interaction is formed between the infrared absorbing material and the polar group of the water-insoluble and alkali-soluble resin, and a positive-type photosensitive layer is formed.
General water-insoluble and alkali-soluble resins are described in detail below. Among them, for example, polyamide resins, epoxy resins, polyacetal resins, acrylic resins, methacrylic resins, polystyrene resins, novolak type phenol resins, and the like are preferable. be able to.
The water-insoluble and alkali-soluble resin that can be used in the present invention is not particularly limited as long as it has a property of dissolving when contacted with an alkaline developer, but the main chain and / or side chain in the polymer is acidic. It is preferably a homopolymer containing a group, a copolymer thereof, or a mixture thereof.
The water-insoluble and alkali-soluble resin having such an acidic group preferably has a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. Accordingly, such a resin can be suitably produced by copolymerizing a monomer mixture containing one or more ethylenically unsaturated monomers having the above functional group. Preferred examples of the ethylenically unsaturated monomer having the functional group include a compound represented by the following formula and a mixture thereof in addition to acrylic acid and methacrylic acid. In the following formulae, R ⁴⁰ represents a hydrogen atom or a methyl group.

  The water-insoluble and alkali-soluble resin that can be used in the present invention is preferably a polymer compound obtained by copolymerizing other polymerizable monomers in addition to the polymerizable monomer. The copolymerization ratio in this case is 10 mol of a monomer that imparts alkali solubility such as a monomer having a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. %, Preferably 20 mol% or more. When the copolymerization component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility is obtained and the developability is excellent.

Examples of other polymerizable monomers that can be used include the compounds listed below.
Alkyl acrylates and alkyl methacrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate.
Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
Acrylamide or methacrylamide such as acrylamide, methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-phenylacrylamide, etc.
Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene.
Other nitrogen atom-containing monomers such as N-vinylpyrrolidone, N-vinylpyridine, acrylonitrile and methacrylonitrile.
N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, Maleimides such as N-cyclohexylmaleimide, N-laurylmaleimide and N-hydroxyphenylmaleimide.
Among these other ethylenically unsaturated monomers, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitrile are preferably used.

Further, as the alkali-soluble resin, the novolak resin mentioned as the component D is also preferable.
It is also possible to use the above water-insoluble and alkali-soluble resin for the single-layer image recording layer.

Furthermore, in the upper layer in the present invention, other resins can be used in combination as long as the effects of the present invention are not impaired. Since the upper layer itself needs to express alkali solubility particularly in the non-image area, it is necessary to select a resin that does not impair this property. From this viewpoint, examples of resins that can be used in combination include water-insoluble and alkali-soluble resins. General water-insoluble and alkali-soluble resins will be described in detail below. Among them, for example, polyamide resins, epoxy resins, polyacetal resins, acrylic resins, polystyrene resins, novolac type phenol resins and the like can be preferably exemplified. .
The amount to be mixed is preferably 50% by mass or less based on the water-insoluble and alkali-soluble resin.

The water-insoluble and alkali-soluble resin preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a weight average molecular weight of 5,000 to 300,000 and a number average molecular weight of 800 to More preferably, it is 250,000. Moreover, it is preferable that the dispersity (weight average molecular weight / number average molecular weight) of the alkali-soluble resin is 1.1 to 10.
Alkali-soluble resin may be used individually by 1 type, or may use 2 or more types together.
The content of the alkali-soluble resin is preferably 2.0 to 99.5% by mass, more preferably 10.0 to 99.0% by mass, more preferably 20.0% with respect to the total mass of the upper layer. More preferably, it is -90.0 mass%. When the addition amount of the alkali-soluble resin is 2.0% by mass or more, the durability of the image recording layer (photosensitive layer) is excellent, and when it is 99.5% by mass or less, both sensitivity and durability are obtained. Excellent.

-Infrared absorbing material-
The upper layer not including at least one of component A to component C may include an infrared absorbing material.
The infrared absorbing material is not particularly limited as long as it is a dye that absorbs infrared light and generates heat, and the above-described infrared absorbing material can be similarly used.
Particularly preferred dyes are cyanine dyes represented by the above formula a.

By including an infrared absorbing material in the upper layer, the sensitivity is improved.
The addition amount of the infrared absorbing material in the upper layer is preferably 0.01 to 50% by mass, more preferably 0.1 to 30% by mass, and more preferably 1.0 to 10% with respect to the total mass of the upper layer. It is particularly preferable that the content is% by mass. When the addition amount is 0.01% by mass or more, the sensitivity is improved, and when it is 50% by mass or less, the uniformity of the layer is good and the durability of the layer is excellent.

-Other ingredients-
In addition, the upper layer in the lithographic printing plate precursor having a two-layer structure may contain an acid generator, an acid proliferation agent, a development accelerator, a surfactant, a bake-out / coloring agent, a plasticizer, a wax agent, and the like.
These components can use each component mentioned above similarly, A preferable aspect is also the same.

<Lower layer>
The lower layer of the lithographic printing plate precursor having a two-layer structure in the invention is preferably the image recording layer containing Component A to Component C.
By containing Component A to Component C in the lower layer, a printing plate having excellent image forming properties and printing durability can be obtained.
Further, by including the components A to C in the lower layer, the printing durability is improved particularly when materials such as low-quality ink and paper are used.
The detailed mechanism for obtaining the above effects is unknown, but the printing durability in printing is presumed to be important for the film strength of the resin used in the lower layer, so the interaction between the binders is strong. It is estimated that the printing durability is improved by using the image recording layer containing the components A to C, which are estimated to have high film strength, as the lower layer.

  When the upper layer is the image recording layer containing component A to component C, the lower layer is preferably the image recording layer containing component A to component C, but the lower layer is at least one of component A to component C. Other image recording layers not included may be used. In this case, the preferred embodiment of the lower layer is the same as the preferred embodiment of the upper layer described above.

<Support>
The support used in the present invention is not particularly limited as long as it is a dimensionally stable plate having necessary strength and durability. For example, paper, plastic (for example, polyethylene, polypropylene, polystyrene) Etc.) laminated paper, 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 on which a metal as described above is laminated or vapor-deposited, or a plastic film.

  The support used in the lithographic printing plate precursor according to the invention is preferably a polyester film or an aluminum plate, and particularly preferably an aluminum plate having good dimensional stability and relatively low cost. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less.

Aluminum that is particularly suitable as the support is pure aluminum, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain slightly different elements.
Thus, the composition of the aluminum plate of the present invention is not specified, and conventionally known and used aluminum plates can be appropriately used.
The thickness of the aluminum plate used in the present invention is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.3 mm. preferable.

Such an aluminum plate may be subjected to a surface treatment such as a roughening treatment or an anodizing treatment as necessary. As for the surface treatment of the aluminum support, for example, degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like, as described in detail in paragraphs 0167 to 0169 of JP-A-2009-175195, Anodizing treatment, anodizing treatment or the like is appropriately performed.
The anodized aluminum surface is subjected to a hydrophilic treatment as necessary.
As the hydrophilization treatment, treatment with an alkali metal silicate (for example, sodium silicate aqueous solution) method, potassium fluoride zirconate or polyvinylphosphonic acid as disclosed in paragraph 0169 of JP-A-2009-175195 is performed. A method or the like is used.
Moreover, the support body described in Unexamined-Japanese-Patent No. 2011-245844 is also preferably used.

<Undercoat layer>
The lithographic printing plate precursor according to the invention may have an undercoat layer between the support and the image recording layer (lower layer) as necessary.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having amino groups such as carboxymethylcellulose and dextrin, organic phosphonic acids, organic phosphoric acids, organic phosphinic acids, amino acids, and hydroxy groups. Preferred examples thereof include hydrochlorides of amines and the like. These undercoat layer components may be used singly or in combination of two or more. Details of the compounds used for the undercoat layer and the method for forming the undercoat layer are described in paragraphs 0171 to 0172 of JP-A-2009-175195, and these descriptions also apply to the present invention.
The coverage of the undercoat layer is preferably 2 to 200 mg / ^{m 2,} and more preferably 5 to 100 mg / ^{m 2.} When the coating amount is in the above range, sufficient printing durability can be obtained.

<Back coat layer>
A back coat layer is provided on the back surface of the support of the planographic printing plate precursor of the present invention, that is, the surface opposite to the surface on which the image recording layer is provided, as necessary.
Such a back coat layer comprises a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. A coating layer is preferably used. Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide obtained therefrom is particularly preferable because of its excellent developer resistance.

(Preparation method of lithographic printing plate)
The preparation method of the lithographic printing plate of the present invention comprises an exposure step of image exposure of the positive lithographic printing plate precursor of the present invention, a development step of developing using an alkaline aqueous solution of pH 8.5 to 13.5, and necessary. Accordingly, it is preferable to include a heating process for performing a heating process (burning process) in this order.
According to the method for producing a lithographic printing plate of the present invention, there is no occurrence of stains due to the remaining film in the non-image area, and the printing durability and chemical resistance after the burning treatment are improved.
The lithographic printing plate of the present invention is a lithographic printing plate prepared from the positive lithographic printing plate precursor of the present invention, and is preferably a lithographic printing plate prepared by the method of preparing a lithographic printing plate of the present invention. .
Hereafter, each process of the preparation method of the lithographic printing plate of this invention is demonstrated in detail.

<Exposure process>
The method for producing a lithographic printing plate of the present invention includes an exposure step of image-exposing the positive lithographic printing plate precursor of the present invention.
As a light source of actinic rays used for image exposure of the positive planographic printing plate precursor of the present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is more preferable. Among them, in the present invention, it is particularly preferable that the image exposure is performed by a solid laser or a semiconductor laser that emits infrared rays having a wavelength of 750 to 1,400 nm.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec.
The energy applied to the positive planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . Within the above range, laser ablation can be suppressed and the image can be prevented from being damaged.

  The exposure in the present invention can be performed by overlapping the light beams of the light sources. Overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the full width at half maximum (FWHM) of the beam intensity. In the present invention, the overlap coefficient is preferably 0.1 or more.

  The scanning method of the light source of the exposure apparatus that can be used in the present invention is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but the multi-channel is preferably used in the case of a cylindrical outer surface type.

<Development process>
The method for producing a lithographic printing plate of the present invention includes a development step of developing using an alkaline aqueous solution (hereinafter also referred to as “developer”) having a pH of 8.5 to 13.5.
The developer used in the development step is preferably pH 12.5 to 13.5.
The developer preferably contains a surfactant, and more preferably contains at least an anionic surfactant or a nonionic surfactant. Surfactant contributes to the improvement of processability.
As the surfactant used in the developer, any of anionic, nonionic, cationic and amphoteric surfactants can be used. As described above, anionic and nonionic surfactants are used. Agents are preferred.
As the anionic, nonionic, cationic, and amphoteric surfactants used in the developer in the present invention, those described in paragraphs 0128 to 0131 of JP2013-134341A can be used.

Further, from the viewpoint of stable solubility or turbidity in water, the HLB value of the surfactant is preferably 6 or more, and more preferably 8 or more.
The surfactant used in the developer is preferably an anionic surfactant or a nonionic surfactant, and has an anionic surfactant containing a sulfonic acid or a sulfonate, an aromatic ring, and an ethylene oxide chain. Nonionic surfactants are particularly preferred.
Surfactants can be used alone or in combination.
The content of the surfactant in the developer is preferably from 0.01 to 10% by mass, and more preferably from 0.01 to 5% by mass.

In order to maintain the developer at pH 8.5 to 13.5, the presence of carbonate ions and hydrogen carbonate ions as buffering agents can suppress pH fluctuations even when the developer is used for a long period of time. It is possible to suppress developability degradation, development residue generation, and the like due to pH fluctuations. In order for carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and bicarbonate may be added to the developer, or the pH is adjusted after adding carbonate or bicarbonate. Thus, carbonate ions and hydrogen carbonate ions may be generated.
The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.

  The total content of carbonate and bicarbonate is preferably 0.3 to 20% by mass, more preferably 0.5 to 10% by mass, and particularly preferably 1 to 5% by mass with respect to the total mass of the developer. . When the total amount is 0.3% by mass or more, developability and processing capacity do not deteriorate, and when it is 20% by mass or less, it becomes difficult to form precipitates and crystals. It becomes difficult to gel and does not interfere with waste liquid treatment.

Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the non-image area photosensitive layer, another alkali agent such as an organic alkali agent may be supplementarily used together. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These other alkaline agents are used alone or in combination of two or more.
In addition to the above, the developer may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, organic solvent, inorganic acid, inorganic salt, and the like. However, when a water-soluble polymer compound is added, the plate surface tends to become sticky especially when the developer is fatigued, so it is preferable not to add it.

  As the wetting agent, the wetting agent described in paragraph 0141 of JP2013-134341A can be suitably used. The wetting agent may be used alone or in combination of two or more. The wetting agent is preferably used in an amount of 0.1 to 5% by mass relative to the total mass of the developer.

  As the preservative, the preservative described in paragraph 0142 of JP2013-134341A can be suitably used. Two or more preservatives are preferably used in combination so as to be effective against various molds and bacteria. The addition amount of the preservative is an amount that exhibits a stable effect on bacteria, fungi, yeast, etc., and varies depending on the type of bacteria, fungi, yeast, etc., but is 0 with respect to the total mass of the developer. The range of 0.01 to 4% by mass is preferable.

  As the chelate compound, a chelate compound described in paragraph 0143 of JP2013-134341A can be suitably used. A chelating agent is selected that is stably present in the developer composition and does not impair the printability. The addition amount is preferably 0.001 to 1.0 mass% with respect to the total mass of the developer.

  As the antifoaming agent, the antifoaming agent described in paragraph 0144 of JP2013-134341A can be suitably used. The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by mass with respect to the total weight of the developer.

  As the organic acid, an antifoaming agent described in paragraph 0145 of JP2013-134341A can be suitably used. The content of the organic acid is preferably 0.01 to 0.5% by mass with respect to the total mass of the developer.

Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (Esso Chemical Co., Ltd.), gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, Xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and polar solvents.
Polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, etc.), ketones (methyl ethyl ketone, cyclohexanone, etc.), esters (ethyl acetate, methyl lactate, propylene) Glycol monomethyl ether acetate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).
When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples thereof include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content of the inorganic salt is preferably 0.01 to 0.5% by mass with respect to the total mass of the developer.

The development temperature is not particularly limited as long as development is possible, but it is preferably 60 ° C. or lower, more preferably 15 ° C. to 40 ° C. In the development processing using an automatic developing machine, the developing solution may be fatigued depending on the processing amount. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. In addition, using an automatic developing apparatus as described in JP-A-9-96910, the reference conductivity for determining the timing of replenishing the developer replenisher is set in consideration of the ratio between processing fatigue and carbon dioxide fatigue. By automatically setting an appropriate value, the activity of the developer may be maintained in a good state for a long time.
An example of development and post-development processing is a method in which alkali development is performed, alkali is removed in a post-water washing step, gumming is performed in a gumming step, and drying is performed in a drying step. As another example, a method in which pre-water washing, development and gumming are simultaneously performed by using an aqueous solution containing carbonate ions, hydrogen carbonate ions and a surfactant can be preferably exemplified. Therefore, the pre-water washing step is not particularly required, and it is preferable to perform the drying step after performing pre-water washing, development and gumming in one bath only by using one liquid. After development, it is preferable to dry after removing excess developer using a squeeze roller or the like. When the obtained lithographic printing plate has an unnecessary image portion, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-5-174842 can also be used.

  The development process can be preferably carried out by an automatic processor equipped with 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 conveying a lithographic printing plate precursor after image exposure, or a cylinder An automatic processing machine described in the specifications of US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rubs the lithographic printing plate precursor after image exposure set thereon while rotating the cylinder Etc. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the strength of the waist 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, a metal or plastic in which brush materials are implanted in a row, as described in JP-A-58-159533, JP-A-3-100554, or JP-A-62-167253 A brush roll in which the groove mold material is radially wound around a plastic or metal roll as a core without any gap can be used.
Brush materials include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6,6 and nylon 6,10, polyacrylonitriles such as polyacrylonitrile and poly (meth) acrylate). , Polyolefin synthetic fibers such as polypropylene and polystyrene). For example, fibers having a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm can be preferably used.
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. It is preferable to use a plurality of rotating brush rolls.

  The rotating direction of the rotating brush roll may be the same or opposite to the conveying direction of the lithographic printing plate precursor. However, when two or more rotating brush rolls are used, at least one rotating brush roll is used. It is preferred that the rotating brush rolls rotate in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the photosensitive layer in the non-image area. It is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

It is preferable to provide a drying step continuously or discontinuously after the development step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.
In the method for preparing a lithographic printing plate according to the present invention, an automatic processor capable of obtaining a lithographic printing plate by performing development and gumming on a lithographic printing plate precursor in a developing tank and then drying in a drying section. May be used.

<Heating process (burning process)>
The lithographic printing plate production method of the present invention preferably includes a heating step (burning treatment step) for performing a heating treatment (burning treatment) after the development step.
Moreover, in this invention, it is preferable to heat-process (burning process), after apply | coating the desensitizing gum if necessary to the lithographic printing plate after a image development process.

The burning process is performed by heating in a range of 150 ° C. or more and 350 ° C. or less with a burning processor (for example, a burning processor sold by FUJIFILM Corporation: “BP-1300”) or the like.
The heating temperature is preferably in the range of 150 ° C to 350 ° C, more preferably 160 ° C to 300 ° C, and still more preferably 180 ° C to 270 ° C. The heating time is preferably in the range of 1 minute to 20 minutes, more preferably 1 minute to 15 minutes, and still more preferably 1 minute to 10 minutes.
As for the heating temperature and the heating time, optimum conditions are selected in consideration of the types of components forming the image.

In the burning process, before the burning process, a surface-conditioning liquid as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to process. As the method, a method of applying the surface-adjusting liquid onto the lithographic printing plate with a sponge or absorbent cotton soaked with the surface-adjusting liquid, or immersing and applying the printing plate in a vat filled with the surface-adjusting liquid The method, the method of apply | coating with an automatic coater etc. are applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.
The coating amount of the surface conditioning liquid is preferably 0.03 to 0.8 g / m ² (dry mass).

The lithographic printing plate that has been subjected to the burning treatment can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound or the like is used. If so, so-called desensitizing treatment such as gumming can be omitted.
The lithographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets. The planographic printing plate of the present invention can be suitably used for offset printing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In this example, “parts” and “%” mean “parts by mass” and “mass%” unless otherwise specified.

(Synthesis example)
<Synthesis Example of Polymer A-1>
Propylene glycol monomethyl ether acetate (PGMEA) (89 parts) was placed in a three-necked flask and heated to 90 ° C. in a nitrogen atmosphere. A PGMEA solution in which MOI-BM was dissolved was added dropwise to PGMEA in a three-necked flask over 2 hours. After completion of the dropwise addition, the reaction was terminated by stirring for 2 hours. Thereby, a polymer A-1 was obtained. The ratio of the total amount of PGMEA and solid content was 60:40. That is, a polymer solution having a solid content concentration of 40% was prepared. (Mw: 14,000, Mw / Mn: 1.8)
MOI-BM: (Showa Denko Co., Ltd., the following compound)

<Synthesis Example of Polymer A-2>
The polymer was synthesized in the same manner as the polymer A-1, except that MOI-BP was used instead of MOI-BM. (Mw: 13,000, Mw / Mn: 1.9)
MOI-BP: (Showa Denko Co., Ltd., the following compound)

<Synthesis Example of Polymer A-3>
The monomer type was changed to MOI-BM (amount to be 80 mol% in all monomer components) and MAA (amount to be 20 mol% in all monomer components), and a polymer was synthesized in the same manner as the polymer A-1. . The solid content concentration was 40 parts by mass. (Mw: 16,000, Mw / Mn: 2.5)
MAA: Methacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

<Synthesis Example of Polymer A-4>
The monomer type was synthesized in the same manner as the polymer A-3 except that 4-methacrylamideamidobenzenesulfonamide (manufactured by FUJIFILM Fine Chemicals Co., Ltd.) was used instead of MAA. (Mw: 19,000, Mw / Mn: 2.7)

<Synthesis example of polyurea resin (PU-1)>
To a three-necked flask equipped with a condenser and a stirrer, 4.32 parts of 3,3′-dihydroxybenzidine (DADHB, manufactured by Tokyo Chemical Industry Co., Ltd.) and cyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0. 0083 parts, 33.6 parts of N, N-dimethylacetamide (manufactured by Kanto Chemical Co., Inc.) were weighed, and the reaction solution was allowed to reach room temperature (25 ° C., the same applies hereinafter) to obtain a uniform solution.
Hexamethylene diisocyanate (HDI, manufactured by Tokyo Chemical Industry Co., Ltd.) (3.36 parts) was dissolved in N, N-dimethylacetamide (Kanto Chemical Co., Ltd.) (10.00 parts), and the solution was added at room temperature using a dropping funnel. After dropwise addition over a period of time, the mixture was allowed to react at room temperature for 30 minutes, and then 0.30 part of cyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred for 15 minutes. Next, 11.9 parts of methanol was added to the reaction solution, reacted at 65 ° C. for 2 hours, then cooled to room temperature and dissolved.
The said reaction liquid was poured into the liquid mixture of 300 parts of pure waters, and 237 parts of methanol, and the polymer was deposited. This was collected by filtration, washed, and dried to obtain 7.01 parts of a binder polymer (PU-1) having a weight average molecular weight of 56,000.
It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.

<Synthesis example of polyurea resin (PU-2 to 5)>
The diamine component and / or diisocyanate component was changed as shown in Table 1 below, and PU-2 to 5 were synthesized in the same manner as PU-1.

  DADHB, PDABP (manufactured by Tokyo Chemical Industry Co., Ltd.), AHPPHFP (manufactured by Tokyo Chemical Industry Co., Ltd.) and HDI described in Table 1 are the compounds described above, and DABA is the following compound (Tokyo Chemical Industry Co., Ltd.). XDI is m-xylylene diisocyanate.

<Synthesis Example of Sulfonamide-Containing Diamine (SA-1)>
To a three-necked flask equipped with a condenser and a stirrer, 350.0 parts of chlorosulfonic acid was weighed, and then 46.1 parts of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) was added while cooling with ice. The mixture was stirred for 1 hour under ice cooling. The reaction solution was heated to 60 ° C. and stirred for 3 hours. While stirring this reaction solution, it was cooled to room temperature, dropped into 1,000 parts of ice water and 1,492 parts of chloroform mixed solution, stirred for 30 minutes, transferred to a separatory funnel, and the organic layer (chloroform Layer). The chloroform solution was again transferred to a separating funnel, washed with saturated multistory water, then separated and washed twice with pure water, and then separated and washed with saturated saline. The organic layer (chloroform layer) was transferred to an Erlenmeyer flask, 30 parts of magnesium sulfate was added and stirred, and after removing the solid matter by filtration, the chloroform was distilled off using an evaporator and vacuum-dried at room temperature for 24 hours. 70.0 g of the precursor S-1 (4-methylbenzene-1,3-disulfonic acid chloride) of the target product was obtained. The precursor (S-1) was confirmed from the NMR spectrum. The precursor S-1 was analyzed by ¹ HNMR. The results are shown below.
¹ HNMR data (deuterated chloroform, 400 MHz, internal standard: tetramethylsilane) δ (ppm) = 2.95 (s, 3H), 7.73-7.75 (d, 1H), 8.24-8.27 (D, 1H), 8.70 (s, 1H)

  In a three-necked flask equipped with a condenser and a stirrer, 97.3 parts of 1,4-phenylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 400 parts of acetonitrile were weighed and stirred while cooling to 0 to 5 ° C. . After 43.4 parts of the precursor (S-1) obtained above was dissolved in 400 parts of tetrahydrofuran, it was transferred to a dropping funnel and dropped into the stirring three-necked flask over 1 hour, and then 1 hour. Stir. The reaction solution was returned to room temperature and stirred for 2 hours, and then 615 parts of 1M aqueous sodium hydroxide solution and 500 parts of pure water were added and dissolved. The reaction mixture was transferred to a separatory funnel and separated and washed three times with 401 parts of ethyl acetate to recover the aqueous layer. In a beaker, 33.7 parts of ammonium chloride (manufactured by Kanto Chemical Co., Inc.) was weighed, dissolved in 2,000 parts of pure water, and stirred at room temperature. The aqueous layer is dropped into a beaker, the precipitated crystals are collected by filtration, the crystals are reslurry washed with 1,000 parts of pure water, the crystals are collected by filtration, and then the crystals are reslurry washed with 746 parts of chloroform, and then the crystals are filtered. The product was collected and vacuum dried at 40 ° C. for 24 hours to obtain 56.5 g of the desired product (SA-1). The desired product was confirmed from the NMR spectrum.

<Synthesis example of polyurea resin (PU-6)>
To a three-necked flask equipped with a condenser and a stirrer, 5.19 parts of SA-1 obtained above, 0.04 part of sulfanilamide (Tokyo Chemical Industry Co., Ltd.), N, N-dimethylacetamide 25 .8 parts were weighed, and the reaction solution was brought to room temperature to obtain a uniform solution.
Hexamethylene diisocyanate (Tokyo Chemical Industry Co., Ltd.) 4.04 parts, Neostan U-600 (Nitto Kasei Co., Ltd .: bismuth catalyst) 0.01 parts were added in this order, and the mixture was stirred at room temperature for 1 hour, then 60 The reaction was carried out at 3 ° C. for 3 hours. Subsequently, 5 parts of methanol was added and reacted at 90 ° C. for 2 hours to obtain a binder polymer (PU-6) having a weight average molecular weight of 52,000. It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.

<Synthesis Example of Sulfonamide-Containing Diol (SP-1)>
In a three-necked flask equipped with a condenser and a stirrer, 30.54 parts of 2-aminoethanol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 30.0 parts of tetrahydrofuran were weighed and stirred while cooling to 0 to 5 ° C. . After dissolving 20.76 parts of the precursor (S-1) obtained above in 170 parts of tetrahydrofuran, it was transferred to a dropping funnel, and dropped into the stirring three-necked flask over 1 hour, followed by stirring for 1 hour. did. The reaction solution is returned to room temperature and stirred for 2 hours. The reaction solution is transferred to a separatory funnel, dissolved in 902 parts of ethyl acetate, and separated and washed three times with aqueous hydrochloric acid, water, and saturated brine, and the organic layer is recovered. did. The organic layer was dried over magnesium sulfate, filtered, and then ethyl acetate was distilled off using an evaporator to obtain crystals. The crystals were vacuum dried at 40 ° C. for 24 hours to obtain 20.1 parts of the desired product (SP-1). It was confirmed from the NMR spectrum that it was the target product.

<Synthesis example of polyurethane resin (PT-1)>
In a three-necked flask equipped with a condenser and a stirrer, weigh out 18.58 parts of SP-1 and 65.76 parts of N, N-dimethylacetamide (manufactured by Kanto Chemical Co., Inc.), and bring the reaction solution to room temperature. A homogeneous solution was obtained.
8.41 parts of hexamethylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise at room temperature using a dropping funnel over 10 minutes, and then Neostan U-600 (manufactured by Nitto Kasei Co., Ltd .: bismuth catalyst) After adding 0.01 part and stirring for 10 minutes, the reaction liquid was heated to 60 ° C. and stirred for 6 hours. Subsequently, 7.9 parts of methanol was added to the reaction liquid, reacted at 60 ° C. for 2 hours, and then cooled to room temperature.
The reaction solution was poured into a mixed solution of 1,000 parts of pure water and 791 parts of methanol to precipitate a polymer. This was collected by filtration, washed and dried to obtain 26.2 parts of a binder polymer (PT-1) having a weight average molecular weight of 56,000.
It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.

<Synthesis example of polyurethane resin (PT-2)>
2.7 parts 4,4'-diphenylmethane diisocyanate, 14.5 parts toluene-2,4-diisocyanate, 7.0 parts neopentyl glycol in a round bottom three-necked flask equipped with a concentrator and stirrer; 35.8 parts 2,2-bis (hydroxymethyl) propionic acid and 280 parts 3-pentanone were introduced. 0.3 part dibutyltin didodecanoate was added and the reaction mixture was heated to 80 ° C. with stirring. The reaction was continued at 80 ° C. for 6 hours. A polyurethane resin (PT-2) was thus obtained. The weight average molecular weight by GPC was 24,000. The acid value was 125 mgKOH / g.

(Examples 1-21 and Comparative Examples 1-3: Production of planographic printing plate precursor)
<Production of support>
The treatment shown in the following (a) to (k) was applied to an aluminum alloy plate of material 1S having a thickness of 0.3 mm to produce a lithographic printing plate support. In addition, the water washing process was performed between all the process processes, and the liquid draining was performed with the nip roller after the water washing process.

<Processing>
(A) Mechanical roughening treatment (brush grain method)
While supplying a suspension of pumice (specific gravity 1.1 g / cm ³ ) as a polishing slurry liquid to the surface of the aluminum plate, mechanical surface roughening was performed with a rotating bundle-planting brush.
The median diameter (μm) of the abrasive was 30 μm, the number of brushes was 4, and the rotation speed (rpm) of the brushes was 250 rpm. The material of the bunch planting brush was 6 · 10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. The distance between the two support rollers (φ200 mm) at the bottom of the bundle-planting brush was 300 mm. The bundle brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus with respect to the load before the bundle brush was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate.

(B) Alkaline etching treatment The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% with a spray tube at a temperature of 70 ° C. Then, water washing by spraying was performed. The amount of dissolved aluminum was 10 g / m ² .

(C) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous nitric acid solution. The nitric acid aqueous solution used for the desmut treatment was a nitric acid waste solution used for electrochemical roughening in the next step. The liquid temperature was 35 ° C. The desmutting liquid was sprayed and sprayed for 3 seconds.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of nitric acid electrolysis 60 Hz. As the electrolytic solution at this time, an electrolytic solution in which aluminum nitrate was adjusted to 4.5 g / L by adding aluminum nitrate to an aqueous solution having a temperature of 35 ° C. and nitric acid of 10.4 g / L was used. As the AC power supply waveform, the time tp until the current value reaches a peak from zero is 0.8 msec, the duty ratio is 1: 1, and a trapezoidal rectangular wave AC is used to electrochemically roughen the surface using a carbon electrode as a counter electrode. Processed. 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. Amount of electricity (C / dm ²⁾ the aluminum plate was 185C / dm ² as the total quantity of electricity when the anode. Then, water washing by spraying was performed.

(E) Alkaline etching treatment The aluminum plate obtained above was etched by spraying an aqueous caustic soda solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of dissolved aluminum was 0.5 g / m ² .

(F) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. The sulfuric acid aqueous solution used for the desmut treatment was a solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The liquid temperature was 30 ° C. The desmutting liquid was sprayed and sprayed for 3 seconds.

(G) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of hydrochloric acid electrolysis 60 Hz. As the electrolytic solution, an electrolytic solution in which aluminum chloride was adjusted to 4.5 g / L by adding aluminum chloride to an aqueous solution having a liquid temperature of 35 ° C. and hydrochloric acid of 6.2 g / L was used. An electrochemical surface roughening treatment was performed using a trapezoidal rectangular wave alternating current with a time tp of 0.8 msec until the current value reached a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Ferrite was used for the auxiliary anode.
The current density was 25A / dm ² at the peak of electric current amount of hydrochloric acid electrolysis (C / dm ²⁾ the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode. Then, water washing by spraying was performed.

(H) Alkaline etching treatment The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of aluminum dissolved was 0.1 g / m ² .

(I) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. Specifically, desmutting treatment was performed for 4 seconds at a liquid temperature of 35 ° C. using the waste liquid generated in the anodizing treatment step (dissolving 5 g / L of aluminum ions in a 170 g / L aqueous solution of sulfuric acid). The desmutting liquid was sprayed and sprayed for 3 seconds.

(J) Anodizing treatment Anodizing device of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode section length 2.4 m each) Anodizing was performed using this. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 50 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 20 ° C. Then, water washing by spraying was performed.

(K) Silicate treatment In order to ensure the hydrophilicity of the non-image area, a silicate treatment was performed by dipping at 50 ° C. for 7 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution. The adhesion amount of Si was 10 mg / m ² . Then, water washing by spraying was performed.

<Formation of undercoat layer>
The undercoat layer coating solution 1 shown below was applied onto the support produced as described above, and then dried at 80 ° C. for 15 seconds to produce a support A provided with an undercoat layer. The coating amount after drying was 15 mg / m ² .

-Undercoat layer coating solution 1-
-The following copolymer having a weight average molecular weight of 28,000: 0.3 parts-Methanol: 100 parts-Water: 1 part

  In the above formula, Et represents an ethyl group.

<Formation of image recording layer>
After coating the lower layer forming coating liquid composition (I) having the following composition on the support A provided with the undercoat layer obtained as described above with a wire bar, it is dried in a drying oven at 150 ° C. for 40 seconds. The coating amount was as shown in Table 2, and a lower layer was provided. After providing the lower layer, the upper layer forming coating liquid composition (II) having the following composition was applied with a wire bar, dried at 150 ° C. for 40 seconds to obtain a coating amount of 0.2 g / m ² , and the upper layer. A lithographic printing plate precursor was obtained.

-Coating liquid composition (I) for lower layer formation-
-Polymers listed in Table 2: 3.5 parts-Compounds having blocked isocyanate groups listed in Table 2: Addition amounts listed in Table 2-m, p-cresol novolak (m / p ratio = 6/4, Weight average molecular weight 6,000): Addition amount described in Table 2 Infrared absorber (IR dye (1): structure shown below): 0.2 part 4,4′-bishydroxyphenylsulfone: 0.3 part Tetrahydrophthalic acid: 0.4 parts p-Toluenesulfonic acid: 0.02 parts 3-methoxy-4-diazodiphenylamine hexafluorophosphate: 0.06 parts Ethyl violet counter ion to 6-hydroxynaphthalenesulfonic acid Changed: 0.15 part Fluorosurfactant (Megafac F-780, manufactured by DIC Corporation): 0.07 part Methyl ethyl ketone: 30 parts 1-methoxy 2-propanol: 15 parts · N, N-dimethylacetamide: 15 parts

-Upper layer forming coating composition (II)-
Novolac resin (m-cresol / p-cresol / phenol = 3/2/5 (molar ratio), Mw 8,000): 0.68 part Infrared absorber (IR dye (1): the above structure): 0. 045 parts-Fluorosurfactant (Megafac F-780, manufactured by DIC Corporation): 0.03 parts-Methyl ethyl ketone: 15.0 parts-1-methoxy-2-propanol: 30.0 parts-1- ( 4-Methylbenzyl) -1-phenylpiperidinium 5-benzoyl-4-hydroxy-2-methoxybenzenesulfonate: 0.01 parts

<Evaluation of image formability>
Each of the prepared lithographic printing plate precursors was placed in a container containing a developer XP-D manufactured by Fuji Film Co., Ltd. (diluted to a conductivity of 43 mS / cm, pH 13.1, 30 ° C.) for 2 seconds. Each time, the time was changed and immersed, and then washed with water, and the minimum time required for the recording layer to completely dissolve was determined.
Next, the entire surface was exposed with a Trend setter manufactured by Creo at a beam intensity of 15 W and a drum rotation speed of 150 rpm, and the time required for dissolving the recording layer was determined in the same manner as described above. When the dissolution time in unexposed was a, and the dissolution time after exposure was b, the value of a / b was determined and used as a reference for image forming property evaluation. It is evaluated that the larger the obtained value, the greater the effect of promoting dissolution during exposure, the better dissolution discrimination, and the better the image formability.
The results are shown in Table 2.

<Evaluation of printing durability>
-Exposure and development-
Each positive type lithographic printing plate precursor obtained as described above was used to draw a test pattern in an image with a Trendsetter manufactured by Creo at a beam intensity of 9 W and a drum rotation speed of 150 rpm. Thereafter, a developing solution XP-D (manufactured by Fuji Film Co., Ltd., diluted to a conductivity of 43 mS / cm, pH 13.1) was used, and a developing temperature 30 ° C. using a PS processor LP940H manufactured by Fuji Film Co., Ltd. The development was performed with a development time of 12 seconds.

<Heat treatment (burning treatment)>
About Examples 1-21 and Comparative Examples 1-3, it heat-processed for 5 minutes at 235 degreeC using the following baking gum solutions with respect to a part of lithographic printing plate after image development.

-Baking gum solution-
As the baking gum solution, a burning surface-conditioning solution BC-7 manufactured by Fuji Film Co., Ltd. was used.

  As described above, lithographic printing plates of Examples 1 to 21 and Comparative Examples 1 to 3 (the presence or absence of each burning treatment) were obtained.

<Printing>
The obtained lithographic printing plate (before and after burning) was continuously printed using a printing machine Lithlon manufactured by Komori Corporation. As the ink, Toyo Ink ink containing calcium carbonate was used as a model for low-grade materials. At this time, the number of sheets that can be printed while maintaining a sufficient ink density was measured visually to evaluate the printing durability. The larger the number, the better the printing durability. The results are shown in Table 2.
In addition, when printing performance was evaluated under the same conditions as described above except that development was performed while controlling conductivity using a PS processor XP-940R manufactured by FUJIFILM Corporation instead of the PS processor LP940H, In the examples and comparative examples, the results were the same as when the PS processor LP940H was used.

<Evaluation of chemical resistance>
Printing was performed in the same manner as in the evaluation of printing durability. At this time, every time 5,000 sheets were printed, a process of wiping the plate surface 5 times with a PS sponge containing a cleaner (manufactured by Fuji Film Co., Ltd., MC-E) was added to evaluate chemical resistance. In this case, the printing durability is 4, from 100% to less than 95%, 3, from 60% to less than 80%, and from 2, 60% to 80%. Less than 1 was assigned. Even when the process of wiping the printing plate with a cleaner is added, the smaller the change in the number of printing sheets, the better the chemical resistance. The results are shown in Table 2 below.

“Polymer specific mass parts” described in Table 2 and Table 3 and Table 4 described below represent the amount of each corresponding component added to 100 parts by mass of the polymer such as PU-1.
Details of components other than those described in Table 2 are shown below.
CP-1: The following methacrylic acid-methyl methacrylate copolymer (molar ratio 15:85), Mw: 41,000
B-1: Desmodur BL4265SN (manufactured by Sumika Bayer Urethane Co., Ltd., corresponding to the compound represented by the above formula C-3)
B-2: Duranate 17B-60P (Asahi Kasei Chemicals Corporation, corresponding to the compound represented by the above formula C-4)
B-3: Duranate TPA-B80E (Asahi Kasei Chemicals Corporation, corresponding to the compound represented by the formula C-3)
B-4: Desmodur BL3575 / 1 MPA / SN (manufactured by Sumika Bayer Urethane Co., Ltd., corresponding to the compound represented by the above formula C-3)
B-5: Desmodur BL3272 MPA (manufactured by Sumika Bayer Urethane Co., Ltd., corresponding to the compound represented by the above formula C-3)

  As is apparent from the results in Table 2, it can be seen that when the planographic printing plate precursor of the present invention containing a compound having a blocked isocyanate group is used, the printing durability and chemical resistance after the burning treatment are improved. . It can also be seen that the inclusion of the phenolic resin improves the printing durability and image forming property after burning. On the other hand, when the compound having a blocked isocyanate group is added excessively, the printing durability after burning is improved, but it is understood that there is a concern about deterioration of image formability.

(Example 22 and Comparative Example 4)
<Production of support>
A support was prepared in the same manner as in Example 1.

<Formation of undercoat layer>
On the support prepared as described above, the undercoat layer coating solution 2 shown below was applied, followed by drying at 80 ° C. for 15 seconds to provide an undercoat layer to obtain a support B. The coating amount after drying was 15 mg / m ² .

-Undercoat layer coating solution 2-
・ Β-Alanine: 0.5 part ・ Methanol: 95 parts ・ Water: 5 parts

<Formation of image recording layer>
After applying the lower layer forming coating liquid composition (V) having the following composition to the obtained support B with a wire bar so that the coating amount becomes 1.5 g / m ² , the coating is performed in a 160 ° C. drying oven for 40 seconds. It dried and immediately cooled with the cold air of 17-20 degreeC until the temperature of the support body became 35 degreeC, and provided the lower layer. After providing the lower layer, the upper layer forming coating liquid composition (VI) having the following composition was coated with a wire bar so that the coating amount was 0.5 g / m ² , dried at 130 ° C. for 40 seconds, and further 20 to 20 Slow cooling was performed with 26 ° C. wind, and an upper layer was provided to obtain a lithographic printing plate precursor.

-Coating liquid composition for lower layer formation (V)-
N-phenylmaleimide / methacrylic acid / methacrylamide copolymer (molar ratio: 59/15/26, molecular weight: 50,000): 0.8 part Infrared absorber (IR dye (1): the above structure): 0.017 part ・ Crystal violet (manufactured by Hodogaya Chemical Co., Ltd.): 0.017 part ・ Megafac F-177 (manufactured by DIC Corporation, fluorosurfactant): 0.015 part ・ N, N-dimethyl Acetamide: 10 parts Methyl ethyl ketone: 10 parts 1-methoxy-2-propanol: 8 parts

-Upper layer forming coating solution composition (VI)-
-Polyurethane (PT-2): 10 parts-Compound having blocked isocyanate group (A-1): Amount described in Table 3-Ethyl violet: 0.03 parts-MegaFac F-177 (manufactured by DIC Corporation) , Fluorosurfactant): 0.05 parts-3-pentanone: 60 parts-Propylene glycol monomethyl ether-2-acetate: 8 parts

  The resulting lithographic printing plate precursor was developed using a Fuji processor PS processor FLH 85P charged with Kodak developer Goldstar Premium Plate Developer (pH 13.0) for development, and the liquid temperature was set to 23 ° C. The evaluation was performed under the same conditions as in Example 1 except that the development time was 40 seconds. The evaluation results are shown in Table 3.

  As is apparent from Table 3, it can be seen that the printing durability and chemical resistance after burning are improved by including a compound having a blocked isocyanate group.

(Example 23 and Comparative Example 5)
<Production of support>
A support was prepared in the same manner as in Example 1.

<Formation of undercoat layer>
Example 1, Support A having an undercoat layer was produced.

<Formation of image recording layer>
A coating liquid composition (IX) having the following composition is coated on the obtained support A with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to obtain a coating amount described in Table 4. I got the original version.

-Coating liquid composition (IX)-
M, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5,000): 0.474 parts Specific polymer compound (PU-1): 2.37 parts Blocked isocyanate group Compounds: Amounts listed in Table 4 Infrared absorber (IR dye (1) above): 0.155 parts 2-methoxy-4- (N-phenylamino) benzenediazonium hexafluorophosphate: 0.03 parts -Tetrahydrophthalic anhydride: 0.19 parts-Ethyl violet counter ion in the form of 6-hydroxy-β-naphthalenesulfonic acid: 0.11 parts-Fluorosurfactant (Megafac F-780, DIC Corporation) Manufactured): 0.07 part p-Toluenesulfonic acid: 0.008 part Bis-p-hydroxyphenylsulfone: 0.13 part 3,3'-thiodipropion Dimyristyl acid: 0.04 part ・ Lauryl stearate: 0.02 part ・ N, N-dimethylacetamide: 13 parts ・ Methyl ethyl ketone: 24 parts ・ 1-methoxy-2-propanol: 11 parts

  The obtained lithographic printing plate precursor was evaluated under the same conditions as in Example 1 except that the developer LH-DS (pH 13.5) manufactured by Fuji Film Co., Ltd. was used for the development treatment. The evaluation results are shown in Table 4 below.

  As is apparent from Table 4, it can be seen that the printing durability and chemical resistance after burning are improved by including a compound having a blocked isocyanate group.

Claims (22)

As component A, a polymer having a urea bond and / or a urethane bond in the main chain,
As component B, an infrared absorbing material, and
As component C, a compound having a blocked isocyanate group,
A positive lithographic printing plate precursor comprising: an image recording layer comprising: on a support. The positive lithographic printing plate precursor according to claim 1, wherein the blocked isocyanate group is a group represented by the following formula C-1.

In formula C-1, Z represents a monovalent organic group.   The positive planographic printing plate precursor according to claim 1 or 2, wherein Component A is a polymer having a urea bond in the main chain.   The positive planographic printing plate precursor according to any one of claims 1 to 3, wherein Component C is a polymer having a blocked isocyanate group. The positive-type planographic printing plate precursor according to claim 4, wherein the polymer having a blocked isocyanate group has a structural unit represented by the following formula C-2.

In Formula C-2, R ^C1 represents a hydrogen atom or a methyl group, X and Y each independently represent a divalent linking group or a single bond, and Z represents a monovalent organic group.   The positive lithographic printing plate precursor according to claim 5, wherein X is an arylene group or —C (═O) —.   The positive planographic printing plate precursor according to claim 6, wherein X is -C (= O)-.   The positive-type planographic printing plate precursor according to any one of claims 4 to 7, wherein the polymer having a blocked isocyanate group further has an acidic group.   The positive-type planographic printing plate precursor according to claim 8, wherein the acidic group is at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, and a carboxylic acid group.   Z is a group obtained by removing one active hydrogen from a compound selected from the group consisting of a compound having a phenolic hydroxyl group, an oxime compound, a compound having a pyrazole structure, a lactam compound, and an aliphatic alcohol compound, Item 6. The positive planographic printing plate precursor according to Item 2 or 5.   The positive planographic printing plate precursor according to any one of claims 1 to 3, wherein Component C is a compound having a blocked isocyanate group and a molecular weight of less than 1,000.   The positive-type planographic printing plate precursor according to claim 11, wherein Component C is a compound having a molecular weight of less than 1,000 and having three or more blocked isocyanate groups.   The positive-type planographic printing plate precursor according to any one of claims 1 to 12, wherein the content of Component C is 1 to 30 parts by mass with respect to 100 parts by mass of Component A.   The positive planographic printing plate precursor according to any one of claims 1 to 13, wherein the image recording layer further contains a phenol resin as component D.   The positive type lithographic printing plate precursor according to any one of claims 1 to 14, wherein Component A further has an acidic group.   The positive planographic printing plate precursor according to claim 15, wherein the acidic group in component A is an acidic group directly bonded to the main chain.   The positive planographic printing plate precursor according to claim 15 or 16, wherein the acidic group in Component A is at least one group selected from the group consisting of a phenolic hydroxyl group, a sulfonamide group, and a carboxylic acid group.   The positive planographic printing plate precursor according to claim 17, wherein the acidic group in Component A is a phenolic hydroxyl group. The image recording layer is composed of a lower layer and an upper layer,
The positive planographic printing plate precursor according to any one of Claims 1 to 18, wherein the image recording layer containing Component A to Component C is at least one of the lower layer and the upper layer.   The positive planographic printing plate precursor according to claim 19, wherein the image recording layer containing Component A to Component C is at least the lower layer. An exposure step for image-exposing the positive planographic printing plate precursor according to any one of claims 1 to 20, and
a development step of developing using an alkaline aqueous solution of pH 8.5 to 13.5,
Are prepared in this order, and a method for preparing a lithographic printing plate.   The method of preparing a lithographic printing plate according to claim 21, further comprising a heating step of performing a heat treatment after the developing step.