JP4738913B2 - Photosensitive composition and planographic printing plate precursor using the same - Google Patents

Abstract

A photosensitive composition containing: (A) a first alkaline aqueous solution-soluble resin having, on a side chain, a hydrophobic aminoalkyl group represented by the following formula (1); (B) a second alkaline aqueous solution-soluble resin, and (C) an infrared absorber: wherein Z 1 , Z 2 and Z 3 each independently represent a hydrogen atom or a monovalent substituent group consisting of one or more nonmetal atoms.

Description

  The present invention relates to a photosensitive composition and a lithographic printing plate precursor using the same. More specifically, the present invention is capable of direct plate making by scanning with infrared laser light based on a digital signal from a computer or the like. The present invention relates to a positive planographic printing plate precursor and a photosensitive composition having sensitivity to infrared rays useful as a recording layer thereof.

In recent years, with the development of image forming technology, a laser beam with a narrow beam is scanned on the plate surface, and a character document, an image document, etc. are directly formed on the plate surface, thereby making a plate directly without using a film document. Is possible. One of the plate materials used for such direct plate making is a so-called thermal positive type lithographic printing plate. A thermal positive type lithographic printing plate causes photothermal conversion in a photosensitive layer by laser light irradiation to cause alkali solubilization of the photosensitive layer and forms a positive image. Utilizing subtle changes in the intermolecular interaction of the binder in the photosensitive layer, the alkali-soluble discrimination in exposed / unexposed areas is reduced, resulting in poor development latitude (development stability depending on use conditions). There was a problem of becoming enough.
In addition, such a lithographic printing plate is also required to have a resistance to a plate cleaner that is used when the ink becomes poor during printing.

  For this reason, for the purpose of expanding the alkali-soluble development latitude of clear exposed / unexposed portions that can be practically used, for example, as described in Patent Document 1, the image recording layer is made of a highly alkaline-soluble resin (sea portion). ) And a resin (island portion) having low alkali solubility form a sea-island structure, and an image recording layer forming a so-called phase separation structure is known. However, an image forming material in which such an image recording layer has a phase separation structure has insufficient film strength of the recording layer itself, and improvement in scratch resistance has been desired.

In order to improve the cleaner resistance, an image forming material using an alkaline aqueous solution-soluble resin having a phenolic monomer unit in the photosensitive layer has been proposed (see, for example, Patent Document 2), thereby improving the cleaner resistance. However, as with the image forming material described in Patent Document 1, improvement in scratch resistance has been desired.
JP 11-44956 A European Patent Application No. 1506858

Therefore, the present invention has been made to overcome the drawbacks of the prior art described above, and an object thereof is to achieve the following object.
That is, an object of the present invention is to provide a photosensitive composition useful as a recording layer for a positive lithographic printing plate precursor for infrared laser, which has a wide development latitude and is excellent in cleaner resistance and scratch resistance, and a positive electrode using the same. It is to provide a lithographic printing plate precursor.

As a result of diligent research, the present inventor has found a condition for achieving the above-mentioned object.
That is, the photosensitive composition of the present invention, (A) the following general formula (2) first alkaline aqueous solution-soluble resin having hydrophobicity aminoalkyl group is a novolak resin represented in a side chain (hereinafter, (Referred to as a first alkali-soluble resin), (B) a second alkaline aqueous resin-soluble resin (hereinafter referred to as a second alkali-soluble resin, as appropriate), which is a novolak resin different from the first alkaline aqueous resin . ), And (C) an infrared absorber, wherein the blending weight ratio of the first alkaline aqueous solution-soluble resin and the second alkaline aqueous solution-soluble resin is 90:10 to 60:40 or 10:90 to 40 : 60.

(In general formula (2), R represents a hydrogen atom or a substituent selected from a methyl group, an ethyl group, an n-butyl group, and a t-butyl group. Z ¹ , Z ^2, and Z ³ are each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O-COR ¹ , —CO—R ² , —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , a halogen atom, a phosphate group, a phosphonate group, a t-amine group, an amide group, an imide group, and Represents a monovalent substituent consisting of a non-metal atom selected from a sulfonamide group, or an alkylene group, an alkenylene group, a phenylene group, a naphthalene group, a pyridyl group, a pyrazyl group, a pyrimidyl group, a thiazoyl group,-(C ₂ H ₄ O) _n - group (n = 1~12), - ( C 2 H 4 S) n - group (n = 1 to 12), and -Ph-NHSO ₂ - and linking moiety selected from groups a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O-COR 1, -CO-R 2, Terminals selected from —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , halogen atoms, phosphate groups, phosphonate groups, t-amine groups, amide groups, imide groups, and sulfonamide groups. Represents a monovalent substituent consisting of a nonmetallic atom consisting of a moiety, wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a cycloalkyl group or an unsaturated cyclic group . Hydrocarbon group, aryl group, heterocyclic group, aralkyl Represents an amine group or an amine group.)

Moreover, positive planographic printing plate precursor of the present invention comprises a support, a first alkaline aqueous solution having a hydrophobicity aminoalkyl group is a novolak resin represented by (A) the general formula (2) in the side chain A photosensitive resin composition comprising a soluble resin, (B) a second alkaline aqueous solution-soluble resin that is a novolak resin different from the first alkaline aqueous solution-soluble resin, and (C) an infrared absorber. It has a recording layer in which the blending weight ratio of the alkaline aqueous solution-soluble resin and the second alkaline aqueous solution-soluble resin is 90:10 to 60:40 or 10:90 to 40:60.

Although the operation of the present invention is not clear, it is presumed as follows.
That is, the photosensitive composition of the present invention contains two types of alkali-soluble resins, and one (A) first alkali-soluble resin has a hydrophobic aminoalkyl group having a specific structure. The hydrophobic aminoalkyl group of the (A) first alkali-soluble resin can form an interaction with the functional group of the (B) second alkali-soluble resin. As a result, it is presumed that the photosensitive composition of the present invention can form a physically strong film.
In addition, when the compatibility of the two types of alkali-soluble resins constituting the photosensitive composition of the present invention is low, a phase separation structure (sea-island structure) is formed by forming a dispersed phase with one alkali-soluble resin. can do. In addition, as described above, (A) the first alkali-soluble resin has a hydrophobic aminoalkyl group, so that (B) interacts with the functional group of the second alkali-soluble resin, and the sea part in the sea-island structure It is conceivable that the adhesion to the islands will be strengthened.
When such a photosensitive composition of the present invention is applied to the recording layer of a positive lithographic printing plate precursor for infrared laser, the film strength of the entire recording layer is increased, so that the resistance to the plate cleaner (cleaner resistance) ) And scratch resistance are specifically improved, and in an unexposed area, the resistance to an alkaline aqueous developer is improved. It is estimated that the development latitude is increased.

According to the present invention, a strong film can be formed physically and against an alkaline developer, and the development resistance is quickly released by infrared exposure, so that an exposed / unexposed portion of the alkaline developer can be removed. It is possible to provide a photosensitive composition which is greatly different in solubility and useful as a recording layer of a positive planographic printing plate precursor for infrared laser.
Further, the lithographic printing plate precursor of the present invention used for the recording layer containing the photosensitive composition has an effect that it has a wide development latitude and is excellent in cleaner resistance and scratch resistance.

<Photosensitive composition>
The photosensitive composition of the present invention, (A) the general formula first alkaline aqueous solution-soluble resin having hydrophobicity aminoalkyl group is a novolak resin represented by (2) in the side chain (the first alkali-soluble resin) (B) a second alkaline aqueous solution-soluble resin (second alkaline-soluble resin) which is a novolak resin different from the first alkaline aqueous solution-soluble resin , and (C) an infrared absorber, and the first alkaline The blending weight ratio of the aqueous solution-soluble resin and the second alkaline aqueous solution-soluble resin is 90:10 to 60:40 or 10:90 to 40:60.
Below, each component is demonstrated one by one.

[(A) the following formula first alkaline aqueous solution-soluble resin having hydrophobicity aminoalkyl group is a novolak resin represented by (2) in the side chain (the first alkali-soluble resin)]
In the present invention, (A) the first alkali-soluble resin is a resin represented by the following general formula (1) among resins contained in an alkaline aqueous solution-soluble resin having a hydrophobic aminoalkyl group represented by the following general formula (1) in the side chain. It is an alkaline aqueous solution-soluble resin having a hydrophobic aminoalkyl group in the side chain, which is a novolak resin represented by 2) .

  In the general formula (1), Z ¹ , Z ² And Z ^Three Each independently represents a monovalent substituent consisting of a hydrogen atom or a nonmetallic atom.

In the general formula (2), R represents a hydrogen atom or a substituent selected from a methyl group, an ethyl group, an n-butyl group, and a t-butyl group, and Z ¹ , Z ² , and Z ³ are Each independently represents a monovalent substituent consisting of a hydrogen atom or a non-metallic atom, and the monovalent substituent consisting of the non-metallic atom is a linking site and a terminal selected from the linking sites and terminal sites listed below. Or a monovalent substituent formed only from a terminal site selected from the terminal sites listed below.
Moreover, the monovalent substituent consisting of a nonmetallic atom represented by Z ¹ , Z ² , or Z ³ may be further substituted with an alkyl group, an aryl group, or the like.

The linking moiety, alkylene group, an alkenylene group, phenylene, arylene groups such as naphthalene, pyridyl, pyrazinyl, pyrimidyl, heterocyclic group containing a heteroatom such as _{thiazolyl, - (C 2 H 4 O} ) n - group (n = _{1~12), - (C 2 H} 4 S) n - group (n = 1~12), - Ph -NHSO 2 - group, or the like combinations thereof.

As the terminal portion, a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, - O—COR ¹ , —CO—R ² , —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , halogen atom, phosphate group, phosphonate group, t-amine group, amide group, imide Group, sulfonamide group and the like. Here, R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a cycloalkyl group , an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl group, or an amine group. Selected.

Hereinafter, although the preferable structure of the 1st alkali-soluble resin in this invention is shown, this invention is not limited to these.
Incidentally, showing the substituent R in the general formula (2), examples of Z ^1, Z ² and Z ³ in the following Table 1 to Table 3. In addition, the substituents R, Z ¹ , Z ² and Z ³ shown in the following Tables 1 to 3 can be arbitrarily combined.

  Specific examples (compound numbers 1 to 4) of the first alkali-soluble resin represented by the above general formula (2) are listed in Table 4 below, but the present invention is not limited thereto.

  The method for synthesizing the first alkali-soluble resin in the present invention is not particularly limited. For example, in order to substitute a part of the substituent of the phenol resin having a phenoxide substituent with a specific substituent, Thus, it can be produced by reacting with an isocyanate group (nucleophilic addition reaction) using Sn metal as a catalyst. The nucleophilic addition reaction between the phenoxide of the novolak-type phenol resin and the isocyanate group-containing compound can be performed as follows. That is, the total weight of the novolak-type phenol resin for substituting a part of the hydroxyl group with a specific functional group is dissolved in a solvent so as to have a concentration of 20 to 80% by mass (preferably 30 to 70% by mass). With respect to the total number of moles of hydroxyl groups of the novolak-type phenol resin, the isocyanate group-containing compound is added so that the mole ratio thereof is a mole ratio to be substituted with a specific functional group, and further, the mole of the isocyanate group-containing compound using Sn metal as a catalyst. It is added under temperature conditions in the range of 10 ° C. to 200 ° C. so that the molar ratio to the number is 0.5 to 5.0% (preferably 1.0 to 2.5), and the number is maintained while maintaining the temperature range. This can be done by stirring for a period of time. In addition, it is preferable that reaction temperature is the range of 20 to 150 degreeC, and it is more preferable that it is the range of 20 to 100 degreeC. In this case, examples of the solvent used in the above reaction include chloroform, dichloromethane, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), dimethyl ether (DME), tetrahydrofuran (THF), and the like. Tetrahydrofuran (THF) is preferably used. As the Sn metal, dibutyltin dilaurate is preferably used.

  Moreover, as a molecular weight of the 1st alkali-soluble resin in this invention, 2000 or more are preferable in a weight average molecular weight, and 3000-500,000 are more preferable. Further, the number average molecular weight is preferably 1000 or more, and more preferably 2000 to 400,000.

  Furthermore, the content of the hydrophobic aminoalkyl group in the first alkali-soluble resin in the present invention is preferably 1 to 99 mol%, more preferably 5 to 95 mol%, from the viewpoint of cleaner resistance and developability. More preferred is ˜95 mol%.

[(B) Second alkaline aqueous solution-soluble resin (second alkali-soluble resin)]
The (B) a second alkali-soluble resin in the present invention the (A) alkali-soluble resin incompatible with each other and the first alkali-soluble resin is preferably the (A) phase separating the first alkali-soluble resin More preferably, it is an alkali-soluble resin.
Specific examples of such alkali-soluble resins include, for example, alkali-soluble resins including resins having an acidic group such as a phenolic resin in the main chain and / or side chain of a polymer . It is shall be subject to containing a novolak resin as the second alkali-soluble resin.

  The alkali-soluble resin having the acidic group in the main chain and / or side chain of the polymer has the acidic group listed in the following (1) to (6) in the main chain and / or side chain of the polymer. Is mentioned.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

  In the above (1) to (6), Ar represents a divalent aryl linking group, and R represents a hydrogen atom or a hydrocarbon group.

  Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), an alkali-soluble resin having (1) a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable. (1) An alkali-soluble resin having a phenol group or (2) a sulfonamide group is more preferable from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength. Most preferred are those in the main chain and / or side chain.

(1) Examples of the alkali-soluble resin having a phenol group include the following resins.
For example, a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, a condensation polymer of m- / p-mixed cresol and formaldehyde, phenol And a novolak resin such as a condensation polymer of formaldehyde and cresol (which may be any of m-, p-, or m- / p-mixed) and formaldehyde, and a condensation polymer of pyrogallol and acetone. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned.

Among these, since the discrimination of the resin itself is relatively high, in the present invention, it is necessary to contain a novolac resin as the second alkali-soluble resin .
Examples of the novolak resin include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p -Any of mixing, m- / o-mixing and o- / p-mixing.) Mixed formaldehyde resins are mentioned.

  The novolak resin preferably has a weight average molecular weight of 1,500 or more and a number average molecular weight of 300 or more. More preferably, the weight average molecular weight is 3,000 to 300,000, the number average molecular weight is 500 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

  Examples of other compounds having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

(2) As an alkali-soluble resin having a sulfonamide group, for example, a polymer composed of a minimum constituent unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule.
Among these, in the present invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) As an alkali-soluble resin having an active imide group, for example, a polymer composed of a minimum constituent unit derived from a compound having an active imide group as a main constituent can be mentioned. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

  Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

Before SL (1) to the minimum constituent unit having an acidic group selected from (6) it is not necessarily limited to one particular unit, the minimum block unit having the same acidic group 2 or more, or a different acidic groups What copolymerized 2 or more types of the minimum structural unit which has can also be used.
In the copolymer, a compound having an acidic group selected from (1) to (6) to be copolymerized is preferably contained in an amount of 10 mol% or more, and is contained in an amount of 20 mol% or more. Those are more preferred. When the content is less than 10 mol%, the development latitude improving effect due to the addition tends not to be sufficiently obtained.
Examples of such a copolymer include N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate .

  The second alkali-soluble resin in the present invention preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

Among the above-described alkali-soluble resins, novolak resins are particularly used . Specifically, (A) the hydrophobic aminoalkyl group of the first alkali-soluble resin, and (B) the second alkali-soluble resin as the second alkali-soluble resin. The —OH group in the novolak resin forms an interaction such as a hydrogen bond, and improves the film strength of the photosensitive composition. As a result, the strength of the entire photosensitive layer using the photosensitive composition is increased, This is preferable from the viewpoint of improving scratch resistance.

In the photosensitive composition of the present invention, the total content of (A) the first alkali-soluble resin and (B) the second alkali-soluble resin is 30 to 99 mass from the viewpoint of cleaner resistance and stable film quality maintenance. % Is preferable, a range of 40 to 95% by mass is more preferable, and a range of 50 to 90% by mass is still more preferable.

Further, (A) mixing weight ratio of the first alkali-soluble resin and (B) a second alkali-9 0: 10 to 60: 40 The 10: 90-40: Ru 60 der.

[(C) Infrared absorber]
(C) As an infrared absorber, a well-known various pigment, dye, etc. are mentioned suitably.
Examples of the pigment include a commercially available pigment and color index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “ Examples thereof include pigments described in "Printing Ink Technology", published by CMC Publishing, 1984).

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

  The pigment may be used without being subjected to a surface treatment or may be used after being subjected to a surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (for example, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The surface treatment method is described in “Characteristics and Applications of Metal Soap” (Sachishobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). .

  The particle diameter of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.1 to 1 μm. When the particle size of the pigment is less than 0.01 μm, it may be undesirable from the viewpoint of stability of the dispersion in the photosensitive layer coating solution. On the other hand, when the particle size exceeds 10 μm, the photosensitive layer is uniform. It is not preferable in terms of sex.

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

  Examples of the dyes include commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970). For example, azo dyes, metal complex azo dyes, Examples of the dye include pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. Among the pigments or dyes, pigments and dyes that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near infrared light.

  Carbon black is preferably used as the pigment that absorbs the infrared light or near infrared light. Examples of the dye that absorbs the infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Examples thereof include squarylium dyes described in JP-A-58-112792, and cyanine dyes described in British Patent 434,875.

  Further, as the dye, a near-infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and substituted arylbenzo (described in US Pat. No. 3,881,924) Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US Pat. The pentamethine thiopyrylium salt described in No. 283,475 and the pyrilylation disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 Things like, as commercially available products, the Eporin Co., EpolIghtIII-178, EpolIghtIII-130, EpolIghtIII-125, EpolIghtV-176A or the like are particularly preferably used.

  Moreover, as said dye, as another especially preferable example, the near-infrared absorptive dye described as U.S. Pat. No. 4,756,993 as the formulas (I) and (II) can be mentioned.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and one particularly preferred example is a cyanine dye represented by the following general formula (i).

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

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or 6-membered ring. It is particularly preferable that a 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. Preferred substituents include hydrocarbon groups having 12 or less carbon atoms, halogen atoms, and alkoxy groups having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Z ¹⁻ represents a counter anion. However, when the cyanine dye represented by the general formula (i) has an anionic substituent in its structure and charge neutralization is not necessary, Z ¹⁻ is not necessary. Z ¹⁻ is preferably a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexafluoro ion, in view of storage stability of the coating solution. Phosphate ion and aryl sulfonate ion.

  (C) The amount of the pigment or dye used as the infrared absorber is preferably 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, based on the total solid content of the photosensitive composition. In the case of the dye, 0.5 to 10% by weight is particularly preferable, and in the case of a pigment, 3.1 to 10% by weight is particularly preferable. When the added amount of the pigment or dye is within the above range, preferable recording sensitivity when used as a positive recording layer, and excellent uniformity and durability of the recording layer can be obtained.

<Positive planographic printing plate precursor>
Positive planographic printing plate precursor of the present invention comprises a support, (A) a first alkaline aqueous solution-soluble to have a hydrophobicity aminoalkyl group is a novolak resin represented by the general formula (2) in the side chain A recording layer comprising a resin, (B) a second alkaline aqueous solution-soluble resin that is a novolak resin different from the first alkaline aqueous solution-soluble resin, and (C) a photosensitive composition containing an infrared absorber. Features.
That is, the lithographic printing plate precursor according to the present invention is characterized in that the above-mentioned photosensitive composition according to the present invention is contained in a recording layer.
The lithographic printing plate precursor according to the invention will be described below.

[Layer structure of recording layer]
The recording layer of the lithographic printing plate precursor according to the invention can be preferably used, for example, as a photosensitive layer having a phase separation structure as described in JP-A-11-44956, but is not limited thereto.

[Other ingredients]
In the photosensitive composition constituting the recording layer of the lithographic printing plate precursor according to the invention, in addition to the essential components (A) to (C), various additives may be added as necessary. it can.
For example, in order to adjust the solubility of the recording layer, when an onium salt, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, a polyfunctional amine compound, or the like is added, the alkali-soluble resin (A) or (B) described above is added. It is preferable to add a so-called dissolution inhibitor that improves the function of inhibiting dissolution in the developer. Among them, it is possible to develop an image portion by using together a substance that is thermally decomposable, such as an onium salt, an o-quinonediazide compound, a sulfonic acid alkyl ester, and that substantially reduces the solubility of the alkali-soluble resin when not decomposed. This is preferable from the viewpoint of improving the dissolution inhibition property to the liquid.

  Preferred examples of the onium salt used in the present invention include S.P. I. SchlesInger, Photogr. ScI. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. CurIng ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. CrIvello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. CrIvello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. CrIvello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer ScI. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. CrIvello et al, Polymer Bull. 14, 279 (1985), J. Am. V. CrIvelo et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. CrIvello et al, J. MoI. Polymer ScI. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. CrIvello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. CrIvello et al, J. MoI. Polymer ScI. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. CurIng ASIA, p478 Tokyo, Oct (1988).

  Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) in Chemical formula [Chemical Formula 5] and [Chemical Formula 6] of Unexamined-Japanese-Patent No. 2002-229186 is preferable.

  Further, counter ions of onium salts include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfone. Acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5 -Sulphonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, p-toluenesulfonic acid and the like can be mentioned. Among these, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalene sulfonic acid and 2,5-dimethylbenzene sulfonic acid are particularly preferable.

Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the recording layer by both the effects of losing the ability to suppress the dissolution of the binder by thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance.
Examples of the o-quinonediazide compound used in the present invention include J. Although compounds described in pages 339 to 352 of “Light-Sensitive Systems” (John Wiley & Sons. Inc.) by Korser can be used, in particular, o-reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. Preferred are sulfonic acid esters or sulfonic acid amides of quinonediazide. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 10% by mass, based on the total solid content of the photosensitive composition or recording layer. It is 5 mass%, Most preferably, it is the range of 1-2 mass%.
These compounds can be used alone, but may be used as a mixture of several kinds.

Moreover, the addition amount of degradable dissolution inhibitors other than onium salts and o-quinonediazide compounds is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1%. 0.5% by mass.
The dissolution inhibitor in the present invention is preferably contained in the same layer as the alkali-soluble resin from the viewpoint of expression of its function.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton and also serving as a colorant, as well as nonionic surfactants described in detail in JP-A No. 2000-105454.

In addition, cyclic acid anhydrides, phenols, and organic acids can be used in combination with the photosensitive composition constituting the recording layer of the lithographic printing plate precursor according to the invention for the purpose of improving sensitivity.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, and tetrachlorophthalic anhydride described in US Pat. No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used.
As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 "-Trihydroxytriphenylmethane, 4,4 ', 3", 4 "-tetrahydroxy-3,5,3', 5'-tetramethyltriphenylmethane and the like.
Furthermore, examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942, JP-A-2-96755, and the like. Etc.
The proportion of the cyclic acid anhydride, phenols, and organic acids in the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by mass.

  In addition to these, epoxy compounds, vinyl ethers, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group, and the present inventors described in JP-A-8-276558. A crosslinkable compound having an alkali dissolution inhibiting effect described in JP-A-11-160860 can be appropriately added according to the purpose.

The photosensitive composition constituting the recording layer of the lithographic printing plate precursor according to the invention is added with a printing agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant. Can do.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

  In addition to the above-mentioned salt-forming organic dyes, other dyes can be used as the image colorant. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the recording layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the recording layer.

  Furthermore, a plasticizer is added to the photosensitive composition constituting the recording layer of the lithographic printing plate precursor according to the present invention, if necessary, in order to impart flexibility 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.

  In addition, it is preferable to add a surfactant to the photosensitive composition constituting the recording layer of the lithographic printing plate precursor according to the invention in order to broaden the processing stability against the development conditions. As this surfactant, a fluorosurfactant is suitable.

[Coating solvent and coating method]
The lithographic printing plate precursor according to the invention can be produced by dissolving the photosensitive composition according to the invention in a solvent and applying the solution on a suitable support to form a recording layer. Further, depending on the purpose, a protective layer, a resin intermediate layer, a backcoat layer and the like, which will be described later, can be formed in the same manner.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.

The coating amount (solid content) of the recording layer on the support obtained after coating and drying varies depending on the application, but generally, the coating amount after drying is 0.5 to 5.0 mg from the viewpoint of sensitivity and film properties. / m ² and comprising an amount is preferable, and more preferable amount of the 0.6～2.0Mg / m ^2.

  Various methods can be used for applying the recording layer coating liquid. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating, etc. Can be mentioned.

[Support]
The support used in the lithographic printing plate precursor according to the present invention is a dimensionally stable plate-like material, and is not particularly limited as long as it satisfies physical properties such as required strength and flexibility. , Paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper laminated with or vapor-deposited metal as described above, or plastic film.

As a support that can be applied to a lithographic printing plate precursor, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. 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 in which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate that is a conventionally known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image portion of the planographic printing plate is easily damaged, and the ink adheres to the damaged portion during printing. So-called “scratch stains” easily occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

[Undercoat layer]
The lithographic printing plate precursor of the present invention is provided with a recording layer containing the photosensitive composition of the present invention as described above on a support, and if necessary, a support and a recording layer (in the case of multiple layers). Can be provided with an undercoat layer. By providing this undercoat layer, the undercoat layer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, it is presumed that there is an advantage that high sensitivity can be achieved. In addition, since the recording layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, the sensitivity to the infrared laser is maintained well.
In the unexposed area, the recording layer itself that is impermeable to the alkaline developer functions as a protective layer for the undercoat layer, so that the development stability is good and the image is excellent in discrimination. In the exposed area, the components of the recording layer whose dissolution-inhibiting ability is released are quickly dissolved and dispersed in the developer. Since the undercoat layer itself, which is adjacent to the support, is made of an alkali-soluble polymer, it has good solubility in a developer, for example, even when a developer with reduced activity is used. It is considered that this undercoat layer is useful because it dissolves rapidly without the formation of a film and the like and contributes to the improvement of developability.

  Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid which may have a substituent, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

  Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

In the above formula, R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. , -OR ¹⁴ , -COOR ¹⁵ , -CONHR ¹⁶ , -COR ¹⁷ , or -CN, or R ¹² and R ¹³ may combine to form a ring, and R ^{14 to} R ¹⁷ are each independently X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, It represents an aryl group or a substituted aryl group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

Moreover, as a suitable undercoat layer component in the present invention, there can be mentioned a polymer compound having a component having an acid group and a component having an onium group, as described in JP-A No. 2000-241962. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , —CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium salt is an onium group composed of Group V or Group VI atoms, more preferably an onium salt composed of a nitrogen atom, a phosphorus atom or a sulfur atom, and particularly preferably an onium salt composed of a nitrogen atom. Salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds described in JP-A No. 2000-108538, JP-A No. 2004-94075, Japanese Patent Application No. 2004-73073, and the like can be used as necessary.

These undercoat layers can be provided by the following method.
That is, a method in which a solution prepared by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is applied on a support (aluminum plate) and dried, and water or methanol The substrate is immersed in a solution in which the above organic compound is dissolved in an organic solvent such as ethanol or methyl ethyl ketone, or a mixed solvent thereof, to adsorb the above compound, and then washed with water or the like and dried to form an undercoat layer. It is a method of providing.
In the former method, a solution of the organic compound having a concentration of 0.005 to 10% by mass can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the recording layer.
The coverage of the undercoat layer, from the viewpoint of the expression of printing durability, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2.

(Image formation)
Since the lithographic printing plate precursor according to the invention contains the photosensitive composition described above in the recording layer, an image is formed by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.

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, and the energy applied to the recording material is preferably 10 to 500 mJ / cm ² .

  The developer that can be applied to the lithographic printing plate precursor according to the invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used for the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer, which is an aqueous solution called “silicate developer” having a pH of 12 or more, does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

In the former, the aqueous solution of alkali metal silicate is represented by the ratio of silicon oxide SIO ₂ which is a component of silicate to alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SIO ₂ ] / [M ₂ O]. ) And the density, the developability can be adjusted. For example, as disclosed in JP-A-54-62004, the molar ratio of SIO ₂ / Na ₂ O is 1.0 to 1.5 (that is, [SIO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having an SIO ₂ content of 1 to 4% by mass is disclosed in JP-B-57-7427. As described, [SIO ₂ ] / [M] is 0.5 to 0.75 (ie, [SIO ₂ ] / [M ₂ O] is 1.0 to 1.5), and SIO ₂ Concentration of 1 to 4% by mass, and the developer contains gram atoms of all alkali metals present therein. In the quasi containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  Further, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of the lithographic printing plate material of the present invention. When this developer is used to develop a lithographic printing plate precursor, the surface of the photosensitive layer is not deteriorated and the thickness of the recording layer can be maintained in a good state. In addition, the lithographic printing plate material generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. Further, the effect of improving discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention is mild, and the difference between the exposed and unexposed areas is likely to occur.

  The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other, or a glycoside in which a reducing group and a non-saccharide are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

  Examples of the trehalose type oligosaccharides include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable in that they have a buffering action in an appropriate pH region and are inexpensive.

These non-reducing sugars may be used alone or in combination of two or more.
The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass. If the content is less than 0.1% by mass, a sufficient buffering effect tends to be not obtained, and if it exceeds 30% by mass, it is difficult to achieve high concentration and the cost tends to increase.

  Examples of the base used in combination with the non-reducing sugar include conventionally known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

  Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.

  The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable. In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

  In addition, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in IonIzatIon Constants of OrganIc AcIdsIn Aqueous SoluteIon published by Pergmon Press.

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (and the like) , Salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m Compounds having a phenolic hydroxyl group such as-, p-cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine , Ki Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  In the developer and replenisher, various surfactants and organic solvents are added as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. it can. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acid, antifoaming agent, hard water, if necessary. Softeners and the like can be added.

Furthermore, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer so that the developer in the developer tank is not changed for a long time. It is known that the PS version can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area.
Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Furthermore, reducing agents such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acids, antifoaming agents, and water softeners are added to the developer and replenisher as necessary. Can also be added.

  The lithographic printing plate developed as described above is post-treated with water-washing water, a rinse solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the lithographic printing plate precursor according to the invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

  In the lithographic printing plate precursor according to the present invention, an image portion unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, film edge trace of the original film). Etc.), the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution to an unnecessary image portion as described in Japanese Patent Publication No. 2-13293, 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-59-174842 can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with a higher printing durability, if desired, Burning process is performed.
In the case of burning a lithographic printing plate, before burning, an adjustment 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 treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the coating amount of the surface conditioning liquid is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  The lithographic printing plate that has been subjected to the burning treatment can be subjected to conventional treatments such as water washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound or the like can be used. When used, 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.

  EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.

[Examples 1-6 , Comparative Examples 1-3]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to a surface of an aluminum plate, it is mechanically rotated by a roller-like nylon brush. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the lower part of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to perform an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

(C) Desmut treatment A desmut treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkaline etching treatment An aluminum plate is etched by spraying at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, and the aluminum plate is dissolved at 0.10 g / m ² , so The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

<Support A>
The steps (a) to (j) were sequentially performed, and the support A was produced so that the etching amount in the step (e) was 3.4 g / m ² .
<Support B>
A support B was prepared by sequentially performing the steps except that the steps (g), (h), and (i) were omitted.

<Support C>
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.
<Support D>
Of the above steps, the steps (a) and (d) (e) (f) are omitted except that the steps are performed in order, and the total amount of electricity in the step (g) is 450 C / dm ² for support. Body D was prepared.
The following support (k) hydrophilic treatment and undercoat treatment were subsequently performed on the supports A, B, C, and D obtained as described above.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment is immersed in a treatment layer of 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silicate. Processing (silicate processing) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

[Undercoating]
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying was 15 mg / m ² .

(Undercoat liquid)
・ The following polymer compound (I or II) 0.3 g
・ Methanol 100g
・ Water 1g

(Formation of recording layer)
Next, after applying any of the coating liquid A to the coating liquid C having the following composition to the support with the undercoat layer obtained above with a wire bar, it is dried in a drying oven at 140 ° C. for 50 seconds, The total coating amount was 1.00 g / m ² .
In addition, it shows in following Table 5 regarding the kind of coating liquid used by each Example and the comparative example.

<Coating liquid A>
-(A) 1st alkali-soluble resin (compound of Table 5) 0.75g
-(B) 2nd alkali-soluble resin (compound of Table 5) 0.25g
・ (C) Cyanine dye P (the following structure) 0.017 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015g
・ Γ-Butyrolactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

<Coating liquid B>
-(A) 1st alkali-soluble resin (compound of Table 5) 0.60g
(B) Second alkali-soluble resin (compound described in Table 5) 0.40 g
・ (C) Cyanine dye P (the above structure) 0.017 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015g
・ Γ-Butyrolactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

<Coating liquid C>
-(A) 1st alkali-soluble resin (compound of Table 5) 0.25g
-(B) 2nd alkali-soluble resin (compound of Table 5) 0.75g
・ (C) Cyanine dye P (the above structure) 0.017 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015g
・ Γ-Butyrolactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

[Evaluation of planographic printing plate precursor]
Next, performance evaluation of the obtained positive planographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3 was performed.
The evaluation test was carried out for the sample stored at 25 ° C. for 14 days after the recording layer was applied.

(Evaluation of development latitude)
On the obtained positive planographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3, a test pattern was drawn in an image with a Trend setter 800 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm. (Exposure).
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. with water dilution (1: 9) until the conductivity reached 37 mS / cm, and Fuji Photo Film Co., Ltd. Using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd., charged with a water diluted (1: 1) solution of Finisher FG-1 manufactured by the manufacturer, the liquid temperature was kept at 30 ° C. and development was performed for 12 seconds. Thereafter, an appropriate amount of DT-2R diluted with water (1: 9) was added to the developer, the conductivity was adjusted to 39 mS / cm, and the lithographic printing plate precursor in which the test pattern was drawn in an image shape as before was developed. . Further, the electrical conductivity was increased by 2 mS / cm, and this operation was continued until a film loss due to image development was observed remarkably.

In these lithographic printing plates of Examples and Comparative Examples after development, the plates developed with each conductivity were confirmed with a 50 × magnifier to see whether there was any stain or coloring due to poorly developed non-image area residual film, The conductivity of the developer that was able to develop well was determined. Next, the conductivity at which the developed film does not decrease in the unexposed area, specifically, the image density of the solid area before development is measured with a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth), and 0 is determined from this image density. The electric conductivity of the developer having a solid portion having an image density of 10 or more was determined.
The development latitude was defined as the electric conductivity of the developer that was able to be developed satisfactorily and the limit of the electric conductivity at which the decrease in the developed film was maintained (the difference between the two). The larger the numerical value, the better the development latitude. The results are shown in Table 5.

(Evaluation of cleaner resistance)
A cleaner solution (manufactured by Fuji Photo Film Co., Ltd .: “Plate Cleaner CL2”) was dropped onto the positive type lithographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3, and the dropping portion after 1 minute The change in density was visually observed and evaluated according to the following criteria. The results are shown in Table 5.
○: No change in concentration Δ: Little change in concentration ×: Large change in concentration

(Scratch resistance evaluation)
After scratching the surface of the recording layer of each of the positive lithographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3 with a rubber needle loaded with a weight, the developer DT-2R was diluted with water (1 9), using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd., charged with a solution in which carbon dioxide gas was blown until the electric conductivity reached 47 mS / cm, and the developing temperature was maintained at 30 ° C. Developed in seconds. Thereafter, the scratched portion was visually observed, and if no scratch was found, an even stronger load was applied and scratched with a rubber needle, which was developed and visually observed in the same manner as described above. This operation was repeated, and the maximum load amount at which no scratch was observed was determined. The larger the value, the better the scratch resistance. The results are shown in Table 5.

In addition, the 1st alkali-soluble resin in Table 5 shows the specific example represented by the compound numbers 1-2, 4 described in the said Table 4, and other alkali-soluble resin represents the following. .
Resin (1): m / p cresol novolac resin
(M / p ratio = 6/4, Mw: 5000)
Resin (2): Phenol / m / p cresol novolac resin
(Phenol / m / p ratio = 5/3/2, Mw: 5000)
Resin (3): N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate
(Molar ratio 36:34:30, weight average molecular weight 50,000)
Further, in the coating liquid A used in Comparative Example 1, the first alkali-soluble resin was not used, and 1.00 g of the resin (1) corresponding to the second alkali-soluble resin was used.
Furthermore, the coating liquid A used in Comparative Example 2 did not use the second alkali-soluble resin, but used 1.00 g of Compound No. 1, which is the first alkali-soluble resin.

As is apparent from Table 5, according to the lithographic printing plate precursors of Examples 1 to 6 of the present invention, lithographic printing plates having a wide development latitude and excellent in cleaner resistance and scratch resistance were obtained. From this, the photosensitive composition of the present invention can form a strong film physically and against an alkaline developer, and the development resistance is quickly released by infrared exposure. It can be seen that it can be suitably used for the recording layer of the plate precursor.
On the other hand, it can be seen that the lithographic printing plate precursor of Comparative Example 1 having a recording layer containing only a novolak resin is inferior in development latitude and inferior in cleaner resistance and scratch resistance.
Further, even if the (A) first alkali-soluble resin according to the present invention is included, the lithographic printing plate precursor of Comparative Example 2 that does not include the (B) second alkali-soluble resin has good cleaner resistance. It can be seen that the development latitude is inferior and the scratch resistance is also inferior.
Furthermore, the lithographic printing plate precursor of Comparative Example 3 having a recording layer containing two types of alkali-soluble resins outside the scope of the present invention has good cleaner resistance, but is inferior in development latitude, and has scratch resistance. It turns out that it is remarkably inferior.

Claims (7)

(A) a first alkaline aqueous solution-soluble resin having a hydrophobic aminoalkyl group in the side chain, which is a novolak resin represented by the following general formula (2), and (B) a novolak different from the first alkaline aqueous solution-soluble resin The blending weight ratio of the first alkaline aqueous solution-soluble resin and the second alkaline aqueous solution-soluble resin is 90:10. The photosensitive composition characterized by being 60:40 or 10: 90-40: 60.

(In General Formula (2), R represents a hydrogen atom or a substituent selected from a methyl group, an ethyl group, an n-butyl group, and a t-butyl group. Z ¹ , Z ^2, and Z ³ represent , each independently, a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O- ^{COR 1, -CO-R 2,} -SO 3 -R 1, -SO 2 -R 1, -CN, -NO 2, a halogen atom, a phosphate group, phosphonate group, t-amine group, an amide group, an imide group, And a monovalent substituent selected from a non-metal atom selected from a sulfonamide group, or an alkylene group, an alkenylene group, a phenylene group, a naphthalene group, a pyridyl group, a pyrazyl group, a pyrimidyl group, a thiazoyl group,-( C ₂ H ₄ O ) _N - group (n = 1~12), - ( C 2 H 4 S) n - group (n = 1 to 12), and -Ph-NHSO ₂ - and linking moiety selected from groups a hydrogen atom, alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O-COR 1, -CO-R 2 , —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , a halogen atom, a phosphate group, a phosphonate group, a t-amine group, an amide group, an imide group, and a sulfonamide group. Represents a monovalent substituent consisting of a nonmetallic atom consisting of a terminal moiety, wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a cycloalkyl group , or an unsaturated group . Cyclic hydrocarbon group, aryl group, heterocyclic group, arral Represents a kill group or an amine group.) In the general formula (2), Z ¹ is any one selected from the following Z ¹ -1 to Z ¹ -5 and Z ¹ -7 to Z ¹ -20, and Z ² and Z ³ are the photosensitive composition according to claim 1, wherein the following Z ²³ -1~Z ²³ is any one combination selected from -20.

3. The photosensitive composition according to claim 1, wherein the first alkaline aqueous solution-soluble resin is a compound selected from compounds represented by the following compound numbers 1 to 4. 4.
On the support, (A) a first alkaline aqueous solution-soluble resin having a hydrophobic aminoalkyl group in the side chain, which is a novolak resin represented by the following general formula (2), (B) the first alkaline aqueous solution-soluble resin A second alkaline aqueous solution-soluble resin which is a novolak resin different from the resin, and (C) a photosensitive composition containing an infrared absorber, the first alkaline aqueous solution-soluble resin and the second alkaline aqueous solution-soluble resin The positive lithographic printing plate precursor has a recording layer having a blending weight ratio of 90:10 to 60:40 or 10:90 to 40:60.

(In general formula (2), R represents a hydrogen atom or a substituent selected from a methyl group, an ethyl group, an n-butyl group, and a t-butyl group. Z ¹ , Z ^2, and Z ³ are each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O-COR ¹ , —CO—R ² , —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , a halogen atom, a phosphate group, a phosphonate group, a t-amine group, an amide group, an imide group, and Represents a monovalent substituent consisting of a non-metal atom selected from a sulfonamide group, or an alkylene group, an alkenylene group, a phenylene group, a naphthalene group, a pyridyl group, a pyrazyl group, a pyrimidyl group, a thiazoyl group,-(C ₂ H ₄ O) _n - group (n = 1~12), - ( C 2 H 4 S) n - group (n = 1 to 12), and -Ph-NHSO ₂ - and linking moiety selected from groups a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an unsaturated cyclic hydrocarbon group, an aryl group, a heterocyclic group, an aralkyl ^{group, -OR 1, -SR 1, -COOR} 1, -O-COR 1, -CO-R 2, Terminals selected from —SO ₃ —R ¹ , —SO ₂ —R ¹ , —CN, —NO ₂ , halogen atoms, phosphate groups, phosphonate groups, t-amine groups, amide groups, imide groups, and sulfonamide groups. Represents a monovalent substituent consisting of a nonmetallic atom consisting of a moiety, wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a cycloalkyl group or an unsaturated cyclic group . Hydrocarbon group, aryl group, heterocyclic group, aralkyl Represents an amine group or an amine group.) In the general formula (2), Z ¹ is any one selected from the following Z ¹ -1 to Z ¹ -5 and Z ¹ -7 to Z ¹ -20, and Z ² and Z ³ are positive planographic printing plate precursor according to claim 4, characterized in that any one combination selected from the following Z ²³ -1~Z ²³ -20.

The positive lithographic printing plate precursor as claimed in claim 4 or 5, wherein the first alkaline aqueous solution-soluble resin is a compound selected from the compounds represented by the following compound numbers 1 to 4.
  A positive lithographic printing plate precursor comprising a step of coating a coating liquid containing the photosensitive composition according to any one of claims 1 to 3 and forming a recording layer on a support. Production method.