JP2006065244A - Positive-type photosensitive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive-type photosensitive composition useful for a positive-type planographic printing plate precursor adaptable to a heat mode, superior in solubility discrimination, good in stain resistance, and thus useful as a recording layer of a planographic printing plate precursor. <P>SOLUTION: The positive-type photosensitive composition contains (A) an infrared absorbing agent and (B) a compound having a triarylsulfonium salt structure wherein a sum of Hammett values of substituents bonded to the aryl skeleton is >0.46. The compound (B) preferably has an anionic structure whose hydrophilicity/hydrophobicity parameter logP is <2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positive photosensitive composition. More specifically, the difference in solubility in an alkaline developer between an exposed portion and an unexposed portion is large, and the plate can be directly made from a digital signal from a computer or the like. The present invention relates to a positive photosensitive composition useful as a recording layer for a lithographic printing plate precursor for an infrared laser.

In recent years, the development of lasers has been remarkable, and in particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can easily obtain high-power and small-sized ones. These lasers are very useful as an exposure light source for making a plate directly from digital data such as a computer.
In a known positive photosensitive image forming material for infrared laser for direct plate making, a novolak resin or the like is used as an alkaline aqueous solution-soluble resin.
For example, as a positive type photosensitive image forming material, a substance capable of generating heat by absorbing light, a variety of onium salts, quinonediazide compounds, and the like in an aqueous alkali soluble resin having a phenolic hydroxyl group such as a novolak resin. A positive photosensitive compound, which acts as a dissolution inhibitor that substantially reduces the solubility of the aqueous alkali-soluble resin in the image area, and is heated by heat in the non-image area. There has been disclosed a technique in which an image is formed so that the dissolution inhibiting ability does not appear and can be removed by development (see, for example, Patent Document 1).

Further, the positive photosensitive image forming material is composed of a substance that generates heat by absorbing light and a resin whose alkali aqueous solution solubility is changed by the heat. Low and non-image areas are disclosed in which an aqueous alkali solution becomes highly soluble by heat and can be removed by development to form an image (see Patent Documents 2 and 3).
In the conventional lithographic printing plate precursor, the novolak resin interacts strongly with the dissolution inhibitor, so that the difference in solubility in the developer between the exposed area and the unexposed area becomes large, and the ink acceptability is excellent. For reasons, it is particularly preferably used. For the same reason, novolak resin is also used for positive-type photosensitive image forming materials for infrared lasers. As the novolak resin, a resin obtained by polymerizing phenols such as phenol, cresol and xylenol using formaldehyde under acidic conditions is generally used.

A wide variety of compounds have been studied as dissolution inhibitors, and it is known that onium salt-type dissolution inhibitors exhibit extremely strong dissolution inhibition ability. However, the addition of a general onium salt compound can improve the alkali resistance of the unexposed area due to its high dissolution inhibiting ability, but it has the problem of causing a decrease in sensitivity. As means for overcoming this problem, a photosensitive composition using a specific onium salt has been disclosed (for example, see Patent Document 4). It has been found that onium salts having such a specific structure exhibit excellent characteristics that achieve both high dissolution inhibiting ability and high sensitivity.
However, in a photosensitive composition using a known onium salt-type dissolution inhibitor, there is still room for improvement in terms of the difference between the developability of the exposed area and the development resistance of the unexposed area. There is currently a need for improvement.
JP-A-7-285275 International Publication No. 97/39894 Pamphlet European Patent Application No. 0823327A2 Japanese Patent No. 2577718

  Accordingly, the object of the present invention is excellent in the difference in solubility in the developer between the exposed area and the unexposed area (dissolvable discrimination: hereinafter referred to as “soluble disk” as appropriate), and the alkali in the exposed area. An object of the present invention is to provide a positive photosensitive composition having excellent solubility. Further, another object of the present invention is a positive type useful as a recording layer of a heat mode-compatible positive type lithographic printing plate precursor having excellent solubility discriminability and developability of an exposed area and suppressing occurrence of stains in a non-image area. It is to provide a photosensitive composition.

As a result of studies, the present inventors have found that the above object can be achieved by using an onium salt having a specific structure, and have completed the present invention.
That is, the positive photosensitive composition of the present invention has (A) an infrared absorber and (B) a triarylsulfonium salt structure, and the sum of Hammett values of substituents bonded to the aryl skeleton is 0. And a compound larger than .46.
Here, (B) a compound having a triarylsulfonium salt structure and a sum of Hammett values of substituents bonded to the aryl skeleton being larger than 0.46 is a compound having a substituent bonded to the aryl skeleton of triarylsulfonium. A preferred embodiment is a compound comprising a cation having a total Hammett value of greater than 0.46 and an anion having a hydrophilicity / hydrophobicity parameter logP of less than 2. In the present invention, the log P of an anion refers to the log P of the acid compound when the anion portion is an acid compound.
These compositions preferably further contain an alkali-soluble resin.

The sulfonium salt compound used in the present invention itself has a function of inhibiting the dissolution of the photosensitive composition in an alkaline aqueous solution, and the cation structure has a total Hammett value of substituents bonded to the aryl skeleton of more than 0.46. Have For this reason, strong hydrophobicity is expressed in the unexposed part due to the strong interaction between the cation part and the polymer and the characteristics of the hydrophobic substituent, and the resistance to dissolution in the developer is improved. In addition, in the non-image area, in addition to the stability due to the main skeleton, thermal decomposition is promoted or the potential is lowered, so that the decomposability of the sulfonium salt at the time of exposure is improved and the dissolution resistance is increased. It is considered that the interaction contributing to the property is quickly released and the development is accelerated by the acid generated during the decomposition, and as a result, good development discretion and good removability of the exposed portion are achieved.
Further, in a preferred embodiment of the present invention, in addition to the cation structure, an anionic structure having a hydrophilicity / hydrophobicity parameter logP of less than 2 and an onium salt structure in which both are ionically bonded is formed. In the non-image area of a lithographic printing plate precursor using such a positive photosensitive composition as a recording layer, the recording layer is quickly removed and developed. By being dispersed in the liquid, it is considered that the hydrophilic surface of the support can be exposed without the formation of a residual film, and the occurrence of stains in the non-image area can be effectively suppressed.

In the present invention, “corresponding to heat mode” means that recording by heat mode exposure is possible.
The definition of the heat mode exposure in this invention is explained in full detail. Hans-Joachim Time, IS & Ts NIP 15: 1999 International Conference on Digital Printing Technologies. As described in p209, a light-absorbing substance (for example, a dye) is photoexcited in a photosensitive material and undergoes a chemical or physical change to form a chemical or physical change from the photoexcitation of the light-absorbing substance that forms an image. It is known that there are two modes in the above process. One is that the photo-excited light-absorbing substance is deactivated by some photochemical interaction (for example, energy transfer, electron transfer) with other reactants in the photosensitive material, and as a result, the activated reactant is The so-called photon mode that causes the chemical or physical change necessary for the above-described image formation, and the other is that the photo-excited light-absorbing material generates heat and deactivates, and the reaction material is converted into the above-described using the heat. This is a so-called heat mode that causes a chemical or physical change necessary for image formation. In addition, there are special modes such as ablation that explosively scatters by the energy of light gathered locally, and multiphoton absorption in which one molecule absorbs a large number of photons at once.

  The exposure process using each of the above modes is called photon mode exposure and heat mode exposure. The technical difference between photon mode exposure and heat mode exposure is whether or not the energy amount of several photons to be exposed can be added to the target energy amount of the reaction. For example, consider that a certain reaction is caused by using n photons. In photon mode exposure, photochemical interaction is used, so that one-photon energy cannot be added together due to the requirement of quantum energy and momentum conservation laws. That is, in order to cause some kind of reaction, a relationship of “one photon energy amount ≧ reaction energy amount” is necessary. On the other hand, in heat mode exposure, heat is generated after light excitation, and light energy is converted into heat and used, so that the amount of energy can be added. Therefore, the relationship “energy amount of n photons ≧ energy amount of reaction” is sufficient. However, this energy amount addition is restricted by thermal diffusion. That is, if the next photoexcitation-deactivation process occurs and heat is generated before the heat escapes from the exposed portion (reaction point) of interest now, due to thermal diffusion, the heat is surely accumulated and added, and the temperature of that portion increases. Leads to. However, when the next heat generation is slow, the heat escapes and does not accumulate. In other words, in the heat mode exposure, even when the same total exposure energy amount is used, the result differs depending on whether a high energy amount of light is irradiated for a short time or a low energy amount of light for a long time. It becomes advantageous for accumulation.

Of course, in the photon mode exposure, a similar phenomenon may occur due to the diffusion of the subsequent reactive species, but basically this does not occur.
That is, in terms of the characteristics of the photosensitive material, in the photon mode, the intrinsic sensitivity of the photosensitive material (energy for reaction required for image formation) with respect to the exposure power density (W / cm ² ) (= energy density per unit time). In the heat mode, the intrinsic sensitivity of the photosensitive material increases with respect to the exposure power density. Therefore, when the exposure time is fixed so that the necessary productivity can be maintained in practice as an image recording material, when comparing the modes, the photon mode exposure usually has a high sensitivity of about 0.1 mJ / cm ^2. However, since the reaction occurs at any small exposure amount, the problem of low exposure fogging in the unexposed area is likely to occur. On the other hand, in the heat mode exposure, the reaction does not occur unless the exposure amount is a certain level or more, and usually about 50 mJ / cm ² is required because of the relationship with the thermal stability of the photosensitive material. The problem is avoided.
In fact, in the heat mode exposure, the exposure power density on the plate surface of the photosensitive material needs to be 5000 W / cm ² or more, preferably 10000 W / cm ² or more. However, although not described in detail here, use of a high power density laser of 5.0 × 10 ⁵ W / cm ² or more is not preferable because of problems such as ablation and contamination of the light source.

Hereinafter, the present invention will be described in detail.
The positive photosensitive composition of the present invention has (A) an infrared absorber and (B) a triarylsulfonium salt structure, and the total Hammett value of substituents bonded to the aryl skeleton is 0.46. A larger compound is contained as an essential component, and other components are contained as necessary.
Hereinafter, each component contained in the recording layer of the positive type image forming material of the present invention will be described in order. First, (B) a compound having a triarylsulfonium salt structure, which is a characteristic component of the present invention, and having a total Hammett value of substituents bonded to the aryl skeleton of greater than 0.46 will be described.

[(B) Compound having a triarylsulfonium salt structure and a sum of Hammett values of substituents bonded to the aryl skeleton being larger than 0.46]
The compound (B) used in the present invention has a triarylsulfonium salt structure and the sum of Hammett values of substituents bonded to the aryl skeleton is larger than 0.46 (hereinafter referred to as a specific sulfonium salt as appropriate). The onium salt is a compound having a cation structure in which the sum of Hammett values (Hammet substituent constant σ) of substituents bonded to the aryl skeleton is greater than 0.46.

-Triarylsulfonium salt structure-
A compound having a triarylsulfonium salt structure is known, for example, as a polymerization initiator. Amer. Chem. Soc. 112 (16), 1990; pp 6004-6015, J. MoI. Org. Chem. 1988; pp5571-5573, WO02 / 081439A1 pamphlet, or European Patent (EP) No. 1113005, etc., can be easily synthesized.

-Substituent bonded to aryl skeleton-
In a specific compound, the substituent bonded to the aryl skeleton of the triarylsulfonium salt structure is preferably an electron-withdrawing substituent, and the sum of Hammett values of the substituents bonded to the three aryl skeletons is greater than 0.46. Therefore, it is preferable that it is larger than 0.60. When the sum of the Hammett values is 0.46 or less, the sensitivity improvement effect that is a feature of the present invention cannot be sufficiently obtained.
The Hammett value represents the degree of electron withdrawing of a cation having a triarylsulfonium salt structure, and there is no particular upper limit from the viewpoint of increasing sensitivity, but from the viewpoint of reactivity and stability, It is preferably more than 0.46 and less than 4.0, more preferably more than 0.50 and less than 3.5, and particularly preferably more than 0.60 and less than 3.0.
In addition, the Hammett value in the present invention uses the numerical value described in Naoki Inamoto, edited by Chemistry Seminar 10 Hammett's Rule-Structure and Reactivity (1983, published by Maruzen Co., Ltd.).

Examples of the electron-withdrawing substituent introduced into the aryl skeleton include a trifluoromethyl group, a halogen atom, an ester group, a sulfoxide group, a cyano group, an amide group, a carboxyl group, and a carbonyl group. The Hammett values of these substituents are shown below. A trifluoromethyl group (—CF ₃ , m: 0.43, p: 0.54), a halogen atom [eg, —F (m: 0.34, p: 0.06), —Cl (m: 0. 37, p: 0.23), - Br (m: 0.39, p: 0.23), - I (m: 0.35, p: 0.18) ], an ester group (e.g., -COCH ₃ , O: 0.37, p: 0.45), a sulfoxide group (for example, —SOCH ₃ , m: 0.52, p: 0.45), a cyano group (—CN, m: 0.56, p: 0.66), an amide group (for example, —NHCOCH ₃ , m: 0.21, p: 0.00), a carboxy group (—COOH, m: 0.37, p: 0.45), a carbonyl group (— CHO, m: 0.36, p: (043)) and the like. The parenthesis represents the introduction position of the substituent in the aryl skeleton and the Hammett value, and (m: 0.50) is the Hammett value of 0.50 when the substituent is introduced at the meta position. Indicates that there is.
Among these substituents, nonionic substituents such as a halogen atom and a halogenated alkyl group are preferable from the viewpoint of hydrophobicity. Among them, —Cl is preferable from the viewpoint of reactivity, and the film has hydrophobicity. From the viewpoint of providing, —F, —CF ₃ , —Cl, and —Br are preferable.

These substituents may be introduced into any one of the three aryl skeletons in the triarylsulfonium salt structure, or may be introduced into two or more aryl skeletons. Moreover, the substituent introduced into each of the three aryl skeletons may be one or plural. If the sum of Hammett values of the substituents introduced into these aryl skeletons exceeds 0.46, the substitution position and the number of substituents are arbitrary. For example, one of the aryl skeletons of a triarylsulfonium salt structure Only one substituent having a particularly large Hammett value (the Hammett value alone exceeds 0.46) may be introduced at one location, and a plurality of substituents are introduced so that the total Hammett value is 0.46. It may be exceeded.
As described above, since the Hammett value of the substituent varies depending on the position of introduction, the sum of Hammett values in the triarylsulfonium salt initiator according to the present invention is determined by the type of substituent, the introduction position, and the number of introductions. It will be.
The Hammett side is usually represented by the m-position and the p-position, but in the present invention, the substituent effect at the o-position is calculated as the same value as the p-position as an index of electron withdrawing.

  The most preferred in the present invention is a sulfonium salt that is trisubstituted with a chloro group, and specifically, one having a triarylsulfonium salt structure in which —Cl is introduced into each of three aryl skeletons is preferable.

As the counter anion of the specific sulfonium salt in the present invention, from the viewpoint of stability, sulfonate anion, benzoylformate anion, PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , carboxylate anion, sulfinate anion, sulfate anion, borate Examples include anions, halogen anions, phosphate anions, phosphonate anions, phosphinate anions, active imide anions, polymer sulfonate anions, and polymer carboxylate anions. As the counter anion, an anion having a hydrophilicity / hydrophobicity parameter logP of less than 2 is most preferably used as described in detail below.

In the following, preferred specific examples [Exemplary compounds (1) to (55)] of the specific sulfonium salt, which is the component (B) in the present invention, have a cation structure and an anion structure suitably used for the cation structure. Although it mentions by illustrating, this invention is not limited to these. In addition, the sum total of Hammett values of the substituents bonded to the aryl skeleton of the cation part of these compounds is
0.69. In the following exemplary compounds, the sum σ of Hammett values of the substituents bonded to the aryl skeleton of the cation part is shown in parentheses, and the logP value of the anion part is shown in parentheses.

In addition, as a preferable aspect in (B) specific sulfonium salt, the compound which has an above-described cation structure and an anion structure whose hydrophilicity / hydrophobicity parameter logP is less than 2 is mentioned. Here, the log P of the anion refers to the log P of the acid compound when the anion part is an acid compound, and the hydrophilicity / hydrophobicity parameter logP of the anion part in the present invention is the acid compound of the anion part. This means the common logarithm of the partition coefficient P (Partition Coefficient) of the acid compound, and how an organic compound is distributed in the equilibrium of a two-phase system of oil (generally 1-octanol) and water. This is a physical property value that expresses as a quantitative numerical value, and can be obtained by the following equation.
logP = log (Coil / Cwater)
Here, Coil represents the molar concentration in the oil phase, Cwater represents the molar concentration in the aqueous phase, and the greater the log P value is, the more positive the oil solubility is. It turns out that it is excellent in water solubility, so that becomes large. This value has a negative correlation with the water solubility of the organic compound, and is widely used as a parameter for estimating the hydrophilicity / hydrophobicity of the compound. In principle, logP is actually measured in a distribution experiment. However, since the experiment is complicated, it is usually calculated using an online measured value database or calculation software estimated from a structural formula. In the present invention, C.I. Hansch, A.D. LogP value estimation program developed by Leo et al.'S Medchem project and Biobyte: CLOGP (Daylight Chemical Systems system: PCLOGS embedded in PCModels (ver 1.02): Algorithm = 4.01 Fragment database = 17 ) Is used.
The hydrophilicity / hydrophobicity parameter logP in the anion structure of the specific sulfonium salt of the present invention is preferably less than 2, and a more preferable value of logP is in the range of −1 to 1 from the viewpoint of alkali developability and film formation.

Specific preferred examples of the compound having an anion having a hydrophilicity / hydrophobicity parameter logP of less than 2 as a specific sulfonium salt which is a preferred embodiment of the component (B) [Exemplary compounds (56) to (80)] are shown below. Examples of the anion structure and the cation structure suitably used for the anion structure will be given as examples, but the present invention is not limited to these examples.
In addition, the sum σ of Hammett values of substituents bonded to the aryl skeleton of the cation part of these compounds is shown in parentheses, and the logP value of the anion part is shown in parentheses.

The (B) specific sulfonium salt may be used alone or in combination of two or more.
These specific sulfonium salts are blended in an amount of 0.1 to 50 wt.% Based on the total solid content of the positive photosensitive composition from the viewpoint of the balance between the solubility of the exposed area in an alkali developer and the development resistance of the unexposed area. %, More preferably 0.5 to 40% by weight, and most preferably 1 to 30% by weight.

In the photosensitive composition of the present invention, an onium salt other than the specific sulfonium salt can be used in combination. Examples of the onium salt include general sulfonium salts other than the specific sulfonium salts described above, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, selenonium salts, arsonium salts, azinium salts, and the like. Of these, ammonium salts are preferred.
Such an onium salt is not particularly limited as long as it decomposes by exposure to light having a wavelength that can be absorbed by the infrared absorber (A) used in the present invention, and generates an acid. , Diazonium salts and sulfonium salts are preferred. Such a general onium salt can be used in the range of 0 to 30% by weight, preferably in the range of 0.5 to 15% by weight, based on the specific sulfonium salt.

[(A) Infrared absorber]
The positive photosensitive composition of the present invention contains (A) an infrared absorber.
The (A) infrared absorber used in the present invention is not particularly limited as long as it is a substance that absorbs an infrared laser used for recording and generates heat. From the viewpoint of compatibility, an infrared absorbing dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferably mentioned.

[Infrared absorbing dye or pigment]
As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, naphthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, (thio) pyrylium salts And dyes such as metal thiolate complexes, indoaniline metal complex dyes, oxonol dyes, diimonium dyes, aminium dyes, croconium dyes, and intermolecular CT dyes.
Examples of preferable dyes include cyanine dyes described in, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. ,
Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595,
JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60- Naphthoquinone dyes described in Japanese Patent No. 63744
Squarylium dyes described in JP-A-58-112792, etc.,
Cyanine dyes described in British Patent 434,875,
Etc.

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted aryl benzoates described in US Pat. No. 3,881,924 are also preferably used. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-220143 No. 59-41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, JP-A 59-216146 Cyanine dyes described in US Pat. No. 4,283,475, pentamethine thiopyrylium salt described in US Pat. No. 4,283,475, etc. Pyrylium compounds disclosed in JP same 5-19702 are also preferably used.

Moreover, as another example preferable as a dye, the near-infrared absorptive dye described as the formula (I) and (II) in US Patent 4,756,993 can be mentioned.
Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes.

  Furthermore, the dyes represented by the following general formulas (a) to (f) are preferable because of excellent photothermal conversion efficiency, and in particular, the cyanine dye represented by the following general formula (a) is used in the present invention. It is most preferable because it gives high interaction with an alkali-soluble resin, functions as a dissolution inhibitor, and is excellent in stability and economy.

In general formula (a), R ¹ and R ² each independently represents an alkyl group having 1 to 12 carbon atoms, and an alkoxy group, an aryl group, an amide group, an alkoxycarbonyl group, a hydroxyl group, sulfo group on the alkyl group. The substituent may be selected from a group and a carboxyl group. Y ¹ and Y ² each independently represent oxygen, sulfur, selenium, a dialkylmethylene group or —CH═CH—. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group, which may have a substituent selected from an alkyl group, an alkoxy group, a halogen atom, and an alkoxycarbonyl group, and is adjacent to Y ¹ and Y ² The aromatic ring may be condensed with two consecutive carbon atoms.

In the general formula (a), X represents a counter ion necessary for charge neutralization, and is not necessarily required when the dye cation portion has an anionic substituent. Q represents a polymethine group selected from a trimethine group, a pentamethine group, a heptamethine group, a nonamethine group or an undecamethine group, and is preferably a pentamethine group, a heptamethine group or a nonamethine group from the viewpoint of wavelength suitability and stability for infrared rays used for exposure. It is preferable in terms of stability to have a cyclohexene ring or a cyclopentene ring containing three consecutive methine chains on any carbon.
In general formula (a), Q is an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a dialkylamino group, a diarylamino group, a halogen atom, an alkyl group, an aralkyl group, a cycloalkyl group, an aryl group, an oxy group, It may be substituted with an iminium base, a group selected from the substituents represented by the following general formula (i), and preferred substituents include halogen atoms such as chlorine atoms, diarylamino groups such as diphenylamino groups, phenylthio And arylthio groups such as groups.

In general formula (i), R < ³ > and R < ⁴ > represent a hydrogen atom, a C1-C8 alkyl group, or a C6-C10 aryl group each independently. Y ³ represents an oxygen atom or a sulfur atom.
Of the cyanine dyes represented by the general formula (a), heptamethine cyanine represented by the following general formulas (a-1) to (a-4) is particularly preferable when exposed to infrared rays having a wavelength of 800 to 840 nm. Mention may be made of pigments.

In general formula (a-1), X ¹ represents a hydrogen atom or a halogen atom. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. Alternatively, it is particularly preferable that a 6-membered ring is formed.
In general formula (a-1), Ar ¹ and Ar ² may be the same or different, and each represents an aromatic hydrocarbon group that may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion necessary for charge neutralization, and Za ⁻ is not necessary when the dye has an anionic substituent in its structure and charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a tetrachlorate ion, in view of the storage stability of the recording layer coating solution. Fluoroborate ion, hexafluorophosphate ion, and sulfonate ion. The heptamethine dye represented by the general formula (a-1) can be suitably used for a positive type image forming material, and in particular, a so-called interaction release type positive photosensitive material combined with an alkali-soluble resin having a phenolic hydroxyl group. Is preferably used.

In general formula (a-2), R ¹ and R ² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ¹ and R ² are bonded to each other to form a ring structure. The ring to be formed is preferably a 5-membered ring or a 6-membered ring, and a 5-membered ring is particularly preferable. 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 on the aromatic hydrocarbon group include hydrocarbon groups having 12 or less carbon atoms, halogen atoms, alkoxy groups having 12 or less carbon atoms, alkoxycarbonyl groups, alkylsulfonyl groups, and halogenated groups. An alkyl group etc. are mentioned, An electron withdrawing substituent is especially preferable. 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. R ⁹ and R ¹⁰ may be the same or different and each may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom Alternatively, R ⁹ and R ¹⁰ may be bonded to each other to form a ring having the following structure.

As R < ⁹ > and R < ¹⁰ > in general formula (a-2), aromatic hydrocarbon groups, such as a phenyl group, are the most preferable among the above.
X ⁻ is a counter anion necessary for charge neutralization and has the same definition as Za ⁻ in the general formula (a-1).

In the general formula (a-3), R ^{1 to} R ⁸ , Ar ¹ , Ar ² , Y ¹ , Y ² and X ⁻ have the same meanings as those in the general formula (a-2). Ar ³ represents an aromatic hydrocarbon group such as a phenyl group or a naphthyl group, or a monocyclic or polycyclic heterosphere group containing at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. Naphthothiazole, thianaphtheno-7,6,4,5-thiazole, oxazole, benzoxazole, naphthoxazole, selenazole, benzoselenazole, naphthselenazole, thiazoline, 2-quinoline, 4-quinoline, 1-isoquinoline, 3-isoquinoline, benzimidazole, 3,3-dialkylbenzoindolenine, 2-pyridine, 4-pyridine, 3,3-dialkylbenzo [e] indole , Tetrazole, triazole, pyrimidine, and thiadiazole Heterocyclic group is preferable to be, include the following structures Particularly preferred heterocyclic groups.

In general formula (a-4), R ^{1 to} R ⁸ , Ar ¹ , Ar ² , Y ¹ and Y ² have the same meanings as in general formula (a-2). R ¹¹ and R ¹² may be the same or different and each represents a hydrogen atom, an allyl group, a cyclohexyl group, or an alkyl group having 1 to 8 carbon atoms. Z represents an oxygen atom or a sulfur atom.
Specific examples of the cyanine dye represented by formula (a) that can be preferably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. And paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents may be bonded to each other to form a ring structure. Good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Ni ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group Or a substituent selected from amino groups, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in general formula (b), L represents a methine chain having 7 conjugated carbon atoms, and R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. It is preferable from the viewpoint of effect.
In the present invention, specific examples of the dye represented by formula (b) that can be suitably used include those exemplified below.

In general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are each a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thiol group, Represents a group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a-1) ^- synonymous.
In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

In general formula (d), R ^{29 to} R ³² each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ taken together, may form a ring, further, when R ³³ or R ³⁴ there are a plurality, R ³³ or between R ³⁴ each other may be bonded to each other to form a ring. X ² and X ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ⁻ represents a counter anion and has the same meaning as Za ⁻ in the general formula (a-1).
In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

In the general formula (e), R ^{35 to} R ⁵⁰ each independently represent a hydrogen atom or a substituent, which may have a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, A carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, an amino group, and an onium salt structure are shown. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein include IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements may be mentioned, among which copper, nickel, magnesium, iron, zinc, tin, cobalt, aluminum, titanium, and vanadium are preferable, and vanadium, nickel, zinc, and tin are particularly preferable. These metal atoms may be bonded to an oxygen atom, a halogen atom or the like in order to make the valence appropriate.
In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

In the general formulas (f-1) and (f-2), R ^{51 to} R ⁵⁸ each independently represent a hydrogen atom or an alkyl group or an aryl group that may have a substituent. X ⁻ has the same meaning as in general formula (a-2).
In the present invention, specific examples of the dyes represented by formulas (f-1) and (f-2) that can be suitably used include those exemplified below.

  Other photothermal conversion agents include dyes having a plurality of chromophores described in JP-A-2001-242613, JP-A-2002-97384, and U.S. Pat. No. 6,124,425. Suitable are pigments in which a chromophore is covalently linked to a molecular compound, an anionic dye described in US Pat. No. 6,248,893, a dye having a surface orientation group described in JP-A-2001-347765, etc. Can be used.

Examples of the pigment used as the photothermal conversion agent in the present invention include commercially available pigments and Color Index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology”. (CMC Publishing, published in 1986), “Printing Ink Technology”, published by CMC Publishing, published in 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 In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

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

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, particularly 0.1 μm, from the viewpoint of the uniformity of the recording layer and the dispersion stability. It is preferable to be in the range of ˜1 μm.

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

The dye or pigment used may be a single compound or a combination of two or more compounds.
These pigments or dyes are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the recording layer, from the viewpoint of balance between sensitivity, stability and uniformity. In the case of a dye, it is particularly preferably 0.5 to 10% by mass, and in the case of a pigment, it is particularly preferably 0.1 to 10% by mass.

[(C) Water-insoluble and alkali-soluble resin]
It is preferable to use (C) a water-insoluble and alkali-soluble resin (hereinafter, appropriately referred to as an alkali-soluble resin) for the photosensitive composition of the present invention. The alkali-soluble resin includes a homopolymer containing an acidic group in the main chain and / or side chain in the polymer, a copolymer thereof, or a mixture thereof.
Among these, those having the acidic groups listed in the following (1) to (6) in the main chain and / or side chain of the polymer are preferable from the viewpoint of solubility in an alkaline developer and expression of dissolution inhibiting ability.

(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 which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .

  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, An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolak resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (any of m-, p-, or m- / p-mixed) and formaldehyde, and pyrogallol and acetone Can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group in the side chain can also be used.

  Examples of the compound 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 them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. For example, the following general formula (i) to general formula ( and a compound represented by v).

[Wherein, X ¹ and X ² each independently represent —O— or —NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , and R ¹⁶ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group, or aralkylene group that may have a substituent. . R ³ , R ⁷ and R ¹³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ¹⁷ each independently represents a C 1-12 alkyl group, cycloalkyl group, aryl group or aralkyl group which may have a substituent. R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ^1, Y ² represents a single bond or CO independently. ]

  Among the compounds represented by the general formula (i) to the general formula (v), in the positive planographic printing plate precursor of 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.

(4) As an alkali-soluble resin having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.
(5) As the alkali-soluble polymer having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and a polymerizable unsaturated group in the molecule is a main structural unit. Can be mentioned.
(6) As an alkali-soluble resin having a phosphate group, for example, a minimum structural unit derived from a compound having at least one phosphate group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

  The minimum structural unit having an acidic group selected from the above (1) to (6) that constitutes the alkali-soluble resin used in the positive photosensitive composition is not necessarily limited to one type, and the same acidic group is used. It is also possible to use a copolymer obtained by copolymerizing two or more minimum structural units having two or more minimum structural units having different acidic groups.

  The copolymer preferably contains 10 mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized, and is contained in an amount of 20 mol% or more. Those are more preferred. If it is less than 10 mol%, the development latitude tends to be insufficiently improved.

In this invention, when copolymerizing a compound and using an alkali-soluble resin as a copolymer, the other compound which does not contain the acidic group of said (1)-(6) can also be used as a compound to copolymerize. Examples of other compounds not containing an acidic group of (1) to (6) include the compounds listed in the following (m1) to (m12), but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  The alkali-soluble resin preferably has a phenolic hydroxyl group from the viewpoint of excellent image-forming properties when exposed to infrared laser or the like. For example, a phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- Preferred are novolak resins such as / p-mixed cresol formaldehyde resin and phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin and pyrogallol acetone resin.

  Further, as an alkali-soluble resin having a phenolic hydroxyl group, as described in US Pat. No. 4,123,279, a carbon number of 3 such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. And a condensation polymer of phenol and formaldehyde having an alkyl group of ˜8 as a substituent.

  The alkali-soluble resin preferably has a weight average molecular weight of 500 or more from the viewpoint of image forming properties, and more preferably 1,000 to 700,000. The number average molecular weight is preferably 500 or more, and more preferably 750 to 650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

Moreover, these alkali-soluble resins may be used alone or in combination of two or more. In the case of combination, it has 3 to 8 carbon atoms such as a condensation polymer of t-butylphenol and formaldehyde or a condensation polymer of octylphenol and formaldehyde as described in US Pat. No. 4,123,279. A polycondensation product of phenol and formaldehyde having an alkyl group as a substituent, an alkali having a phenol structure having an electron-withdrawing group on an aromatic ring described in JP-A-2000-241972 previously filed by the present inventors A soluble resin or the like may be used in combination.

  In the case of using an alkali-soluble resin in the present invention, from the viewpoint of sensitivity, image formability, and film durability, 30 to 98% by weight is preferable in the total solid content of the composition constituting the photosensitive composition, and 40 to 40%. More preferred is 95% by weight.

[Other ingredients]
The photosensitive composition of the present invention may further contain various additives as necessary.
For example, a substance that is thermally decomposable, such as an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, and that substantially reduces the solubility of the alkaline water-soluble polymer compound in a state where it is not decomposed is used in combination. Is preferable in terms of improving the dissolution inhibition of the image portion in the developer.

  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 helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to 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 the compounds described in pages 339 to 352 of “Light-Sensitive Systems” (John Wiley & Sons. Inc.) by Korser can be used, they have been reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulfonic acid esters or sulfonic acid amides of quinonediazides are preferred. Further, benzoquinone (1,2) -diazide sulfonic 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 U.S. 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) -diazide-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, 49-17478, U.S. Pat. Nos. 2,797,213, 3,454,400, and 3,544 No. 323, No. 3,573,917, No. 3,674,495, No. 3,785,825, British Patent No. 1,227,602, No. 1,251,345, No. No. 1,267,005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890 and the like. .
The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of the image forming material. These compounds can be used alone, but may be used as a mixture of several kinds.
The addition amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of the image forming material. is there. The additive and binder in the present invention are preferably contained in the same layer.

  Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, 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. There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric esters and carboxylic acids described in Japanese Laid-Open Patent Publication No. 60-88942 and Japanese Patent Laid-Open No. 2-96755, specifically , P-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate Phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1, Examples thereof include 2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. The ratio of the cyclic acid anhydride, phenols and organic acids in the image forming material is 0.05 to 20%. % By mass is preferable, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass.

In addition, when the photosensitive composition of the present invention is used as a recording layer of a lithographic printing plate precursor, JP-A-62-251740 and JP-A-3-208514 are disclosed in order to broaden the stability of processing with respect to development conditions. Nonionic surfactants as described in JP-A-59-121044, amphoteric surfactants as described in JP-A-4-13149, as described in EP950517 A siloxane compound, a fluorine-containing monomer copolymer as described in JP-A-11-288093 can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.) and the like.

The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the image forming material is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

When the photosensitive composition of the present invention is used for the recording layer, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
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.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. 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 image forming material 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 image forming material.

Furthermore, a plasticizer is added to the photosensitive composition of the present invention as needed 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 to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and the present inventors The crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 proposed in JP-A-11-160860 can be appropriately added depending on the purpose.

  The photosensitive composition of the present invention can be applied to various uses such as a lithographic printing plate precursor, a color proof, and a display material by coating on a suitable support and forming a photosensitive film. It is useful as a recording layer of a lithographic printing plate precursor for heat mode capable of direct plate making by exposure. Hereinafter, the case where the photosensitive composition of the present invention is used as a recording layer of a lithographic printing plate precursor will be described in detail.

[Lithographic printing plate precursor]
Hereinafter, specific examples will be described with reference to an example in which the photosensitive composition of the present invention is applied to a recording layer of a lithographic printing plate precursor.
[Recording layer (image forming layer)]
When the photosensitive composition of the present invention is used as a recording layer for a lithographic printing plate precursor, the composition may be dissolved in a solvent for a coating solution and coated 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 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.

Further, the coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally speaking, 0.5 to 5.0 g / m ² for the recording layer of the lithographic printing plate precursor. preferable. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer decrease.
The recording layer may be a single layer or may have a multilayer structure.

Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
In the recording layer of the present invention, a surfactant for improving the coating property, for example, a fluorine-based surfactant described in JP-A-62-170950 can be added. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in the total solid content of the recording layer.

(Resin intermediate layer)
The lithographic printing plate precursor can be provided with a resin intermediate layer between the recording layer and the support, if necessary.
By providing this resin intermediate layer, the recording layer which is an infrared sensitive layer whose solubility in an alkaline developer is improved by exposure, the sensitivity to the infrared laser is good by being provided on the exposed surface or in the vicinity thereof, A resin intermediate layer made of a polymer exists between the support and the infrared sensitive layer, functions as a heat insulation layer, and heat generated by infrared laser exposure does not diffuse to the support and can be used efficiently for image formation Therefore, there is an advantage that the sensitivity can be increased. In the unexposed area, the recording layer itself that is impermeable to the alkali developer functions as a protective layer for the resin intermediate 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 has been released are quickly dissolved and dispersed in the developer. Since this resin intermediate layer itself that 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 resin intermediate layer is useful because it dissolves quickly without generating a film and the like and contributes to improvement of developability.

[Support]
The support used in the present invention is a dimensionally stable plate, for example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal plate (for example, aluminum). , Zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), Examples include paper or plastic film on which a metal as described above is laminated or vapor-deposited.
The support according to the present invention is preferably a polyester film or an aluminum plate, particularly when used for a lithographic printing plate precursor. Among them, an aluminum plate is particularly preferable because of its good dimensional stability and relatively low cost. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of different elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.

Thus, the composition of the aluminum plate applied to the image forming material of the present invention is not specified, and a conventionally known aluminum plate 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 JP-A-54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. 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 anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the planographic printing plate is easily damaged, and the ink adheres to the damaged part during printing. So-called “scratch dirt” is likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. Examples of the hydrophilization treatment used in the present invention include US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902. There is an alkali metal silicate (for example, aqueous sodium silicate) method as disclosed in US Pat. No. 734. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461, 4,689, A method of treating with polyvinylphosphonic acid as disclosed in the specification of No. 272 is used.

The lithographic printing plate precursor to which the present invention is applied has a positive recording layer provided on a support, and an undercoat layer can be provided between them if necessary.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphone which may have a substituent. Acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphonic acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid which may have a substituent Organic phosphoric acid such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine Hydroxy groups such as hydrochloride Selected from hydrochloride of the amine to be, but may be used by mixing two or more.

This organic undercoat layer can be provided by the following method. That is, a method in which a solution obtained 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 an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the above compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods.
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 a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image forming material.
The coating amount of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. Moreover, even if it is larger than 200 mg / m ^2, it is the same.

[Exposure / Development]
The positive lithographic printing plate precursor produced as described above is usually subjected to image exposure and development processing.
As the light source of the light beam used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.

As a developer and a replenisher for a lithographic printing plate precursor to which the present invention is applied, conventionally known alkaline aqueous solutions can be used.
For example, sodium silicate, potassium, trisodium 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. In addition, 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 also used. These alkali agents are used alone or in combination of two or more.

Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. The reason is that the developability can be adjusted by the ratio and concentration of silicon oxide SiO ₂ and alkali metal oxide M ₂ O, which are silicate components. An alkali metal silicate as described in JP-B-57-7427 is effectively used.

  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 lithographic printing plate precursors 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. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment when the image forming material of the present invention is used as a printing plate, 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 present invention, when there is an unnecessary image portion (for example, a film edge mark of the original film) on the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming. 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 higher printing durability, Processing 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 amount of the surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting liquid 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.). Is done. The heating temperature and time in this case are preferably in the range of 180 to 300 ° C. and 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 burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound or the like is used. If so, so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.
As described above, when the photosensitive composition of the present invention is used as a recording layer of a lithographic printing plate precursor, it is excellent in development discrepancy and forms a high-quality image free from smudges in non-image areas.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Here, the photosensitive composition of the present invention is evaluated by evaluating a lithographic printing plate precursor using the photosensitive composition of the present invention as a recording layer.
(Production of support)
Supports A, B, C, and D were prepared by using a JIS-A-1050 aluminum plate having a thickness of 0.3 mm in combination with the following processes.
(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12. 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 bottom 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) Desmutting treatment Desmutting 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 the 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 is electrochemically roughened using a carbon electrode as the 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) Alkaline etching treatment An aluminum plate is etched by spraying at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C., 0.20 g / m ^{2 of the} aluminum plate is dissolved, 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 by spraying was performed with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (including 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 the 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) 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 at 0.10 g / m ² , 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 dissolved 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 having 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. The electrolyte solutions all 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 performed in order, and the support was prepared so that the etching amount in the step (e) was 3.4 g / m ² .
<Support B>
Except for omitting the steps (g), (h) and (i) among the above steps, each step was performed in order to prepare a support.
<Support C>
A support was prepared by sequentially performing each step except that the steps (a), (g), (h), and (i) were omitted.
<Support D>
Except for omitting the process of the above step (a) and (d) (e) (f ) performs the steps in turn, supported as total amount of electricity is 450C / dm ² in step (g) The body was made.
The supports A, B, C and D obtained as described above were subsequently subjected to the following hydrophilization treatment and undercoating treatment.

(K) Alkali metal silicate treatment An alkali metal silica was obtained by immersing the aluminum support obtained by anodizing treatment in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C for 10 seconds. Acid salt treatment (silicate treatment) 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 16 mg / m ² .

<Undercoat liquid composition>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1.0g

[Examples 1-7, Comparative Examples 1-2]
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support A with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.95 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 130 ° C. for 90 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 1 to 7 and Comparative Examples 1 and 2 were prepared with a total coating amount of 1.25 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 (synthesized by the following) 1.833 g
・ Cyanine dye A (the following structure) 0.098 g
・ 2-Mercapto-5-methylthio-
1,3,4-thiadiazole 0.030 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ 0.100 g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ 3-methoxy-4-diazodiphenylamine 0.030 g
Hexafluorophosphate / fluorine surfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Synthesis of Copolymer 1>
After stirring, 31.0 g (0.36 mol) of methacrylic acid, 39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile were placed in a 500 ml three-necked flask equipped with a condenser and a dropping funnel, and cooled in an ice-water bath. The mixture was stirred while. To this mixture, 36.4 g (0.36 mol) of triethylamine was dropped with a dropping funnel over about 1 hour. After completion of the dropwise addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes.
To this reaction mixture, 51.7 g (0.30 mol) of p-aminobenzenesulfonamide was added, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After completion of the reaction, the mixture was added to 1 liter of water with stirring, and the resulting mixture was stirred for 30 minutes. This mixture was filtered to take out a precipitate, which was slurried with 500 ml of water, and then the slurry was filtered, and the obtained solid was dried to dry a white solid of N- (p-aminosulfonylphenyl) methacrylamide. Was obtained (yield 46.9 g).

  Next, 4.61 g (0.0192 mol) of N- (p-aminosulfonylphenyl) methacrylamide and 2.58 g of ethyl methacrylate (0.0258 mol) were added to a 20 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel. ), 0.80 g (0.015 mol) of acrylonitrile and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name: “V-65”, manufactured by Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator and maintained at 65 ° C. The mixture was stirred for 2 hours under a nitrogen stream. This reaction mixture was further mixed with 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.58 g of methyl methacrylate, 0.80 g of acrylonitrile, 20 g of N, N-dimethylacetamide and 0.15 g of “V-65”. Was dropped by a dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, 40 g of methanol was added to the mixture, cooled, and the resulting mixture was added to 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was removed by filtration and dried. 15 g of a white solid was obtained. It was 54,000 when the weight average molecular weight (polystyrene standard) of this specific copolymer 1 was measured by the gel permeation chromatography.

<Second layer (upper layer) coating solution>
・ Ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.040 g
Copolymer (molar ratio 75:25, weight average molecular weight 70,000)
Phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 50: 30: 20, weight average molecular weight: 8800) 0.400 g
・ Specific sulfonium salt or comparative onium salt 0.1g
・ Cyanine dye A (the above structure) 0.015 g
・ 0.012g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ Fluorosurfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

  The numbers of the specific sulfonium salts listed in Table 1 below are the compound Nos. Of the exemplified compounds. Represents. The structure of the onium salt used in the comparative example is as shown below.

[Evaluation of lithographic printing plate precursor]
The evaluation of the lithographic printing plate precursor was performed for each of the development latitude and stain resistance. Details of the evaluation method are as follows.
1. Development Latitude A lithographic printing plate precursor is stored for 5 days at a temperature of 25 ° C. and a relative humidity of 50%. After that, a test pattern is drawn in an image form with a Trend setter 3244 VX manufactured by Creo at a beam intensity of 10.0 W and a drum rotation speed of 125 rpm. I did.
Thereafter, a PS processor 900H manufactured by Fuji Photo Film Co., Ltd. was used, in which the electric conductivity was changed by changing the mass ratio of water in the alkaline developer of the following A composition and B composition. The liquid temperature was kept at 30 ° C., and development was performed with a development time of 25 seconds. At this time, the developer with the highest and lowest conductivity of the developer in which the image portion is not eluted and there is no stain or coloring due to the residual film of the poorly developed photosensitive layer and the development can be performed satisfactorily. The difference was evaluated as development latitude.

<Alkali developer A composition>
・ SiO ₂ · K ₂ O (K ₂ O / SiO ₂ = 1/1 (molar ratio)) 4.0% by mass
・ Citric acid 0.5% by mass
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 95.0 mass%

<Alkali developer B composition>
・ D sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 96.15% by mass

2. Evaluation of stain resistance in non-image areas Among the lithographic printing plates obtained during the above evaluation, the conductivity of the developer that was able to develop well without being stained or colored due to poorly developed photosensitive layer residual film DIC-GEOS (s) red using a lithographic printing plate obtained by developing with the developer activity at the center of the lowest and the lowest one on a Mitsubishi diamond F2 printer (Mitsubishi Heavy Industries, Ltd.) After printing 10,000 sheets of ink, blanket stains were visually evaluated after printing 10,000 sheets.
The evaluation criteria were ◎ for those that were not soiled at all, ◯ for those that were hardly soiled, and × that were markedly soiled.

<Evaluation of planographic printing plate precursors of Examples 1 to 7 and Comparative Examples 1 and 2>
About each lithographic printing plate precursor of Examples 1-7 and Comparative Examples 1-2, the development latitude and stain resistance were evaluated by the methods described above. Developer B was used as the developer. The results are shown in Table 1.

  As shown in Table 1, it can be seen that the lithographic printing plate precursors of Examples 1 to 7 using the photosensitive composition of the present invention as the recording layer have improved development latitude and stain resistance. On the other hand, Comparative Examples 1 and 2 using an onium salt whose cation structure is outside the scope of the present invention are inferior in development latitude, in particular, a compound having a small cation part Hammett value and a relatively high anion part log P value. It can be seen that in Comparative Example 2 using No., both development latitude and stain resistance are greatly inferior. Further, in comparison between Examples 1 to 6 and Example 7, the effect is particularly remarkable when a sulfonium salt having a cation structure within the scope of the present invention and a log P of the anion portion within a preferable range is used. Was confirmed.

(Examples 8-14, Comparative Examples 3-4)
A coating solution for the first layer (lower layer) having the following composition was coated on the obtained support C with a wire bar, and then dried in a drying oven at 120 ° C. for 90 seconds to obtain a coating amount of 0.60 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 120 ° C. for 90 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 8 to 14 and Comparative Examples 3 to 4 were prepared with a total coating amount of 1.35 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 2.200g
・ Cyanine dye A (the above structure) 0.098 g
・ 2-Mercapto-5-methylthio
-1,3,4-thiadiazole 0.030 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
-The counter anion of ethyl violet is changed to 6-hydroxynaphthalenesulfonic acid 0.100 g
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ Fluorosurfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Dimethylsulfoxide 13.8g

<Second layer (upper layer) coating solution>
・ Ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.040 g
Copolymer (molar ratio 70:30, weight average molecular weight 88,000)
Phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 30: 50: 20,
(Weight average molecular weight: 7700) 0.250 g
・ Specific sulfonium salt or comparative onium salt compound 0.02g
・ Cyanine dye A (the above structure) 0.015 g
・ Fluorine surfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

<Evaluation of Examples 8 to 14 and Comparative Examples 3 to 4>
The obtained planographic printing plate precursors of Examples 8 to 14 and Comparative Examples 3 to 4 were evaluated in the same manner as in Example 1. Developer B was used as the developer. The results are shown in Table 2.
The numbers of specific sulfonium salts listed in Table 2 below are the compound Nos. Of the exemplified compounds. Represents.

  As shown in Table 2, it was confirmed that each of the lithographic printing plate precursors of the Examples achieved improvement in development latitude and stain resistance as compared with the Comparative Examples, and the same results as in Examples 1-7. was gotten. This shows that the lithographic printing plate precursor using the photosensitive composition of the present invention for the recording layer exhibits the same excellent effect even if the components of the photosensitive layer are different.

(Examples 15 to 21, Comparative Examples 5 to 6)
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support D with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.81 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 120 ° C. for 90 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 15 to 21 and Comparative Examples 5 to 6 were prepared with a total coating amount of 1.1 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 2.133 g
・ Cyanine dye A (the above structure) 0.098 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.110 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ 0.100 g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ 3-methoxy-4-diazodiphenylamine 0.030 g
Hexafluorophosphate / fluorine surfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Second layer (upper layer) coating solution>
-Copolymer of ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.0350 g
(Molar ratio 65:35, weight average molecular weight 78,000)
-Cresol-formaldehyde novolak (m-cresol: p-cresol = 60: 40, weight average molecular weight: 4100)
0.300g
-Specific sulfonium salt or comparative onium salt compound 0.0150 g
・ Cyanine dye A (the above structure) 0.015 g
・ Fluorine surfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

<Evaluation of Examples 15 to 21 and Comparative Examples 5 to 6>
The obtained lithographic printing plate precursor was evaluated by the method described above. Developer A was used as the developer. The results are shown in Table 3.
The numbers of specific sulfonium salts listed in Table 3 below are the compound Nos. Of the exemplified compounds. Represents.

  As shown in Table 3, it can be seen that the lithographic printing plate precursors of Examples 15 to 21 have improved development latitude and stain resistance.

(Examples 22 to 28, Comparative Examples 7 to 8)
The following image-forming layer coating solution was applied to the obtained support D and dried at 120 ° C. for 90 seconds to form image-forming layers. The planographic printing plate precursors of Examples 22 to 28 and Comparative Examples 7 to 8 Got. The coating amount after drying was 1.60 g / m ² .

<Image forming layer coating solution>
Phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 50: 30: 20
Weight average molecular weight: 6500) 1.0 g
・ Specific sulfonium salt or comparative onium salt compound 0.05g
・ Cyanine dye A (the above structure) 0.05 g
0.01 g of dye having 1-naphthalenesulfonic acid anion as the counter anion of Victoria Pure Blue BOH
・ Fluorosurfactant 0.05g
(Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 9.0g
・ 9.0 g of 1-methoxy-2-propanol

<Evaluation of Examples 22 to 28 and Comparative Examples 7 to 8>
The obtained lithographic printing plate precursors of Examples 22 to 28 and Comparative Examples 7 to 8 were evaluated in the same manner as in Example 1. Developer A was used as the developer. The results are shown in Table 4.
The numbers of the specific sulfonium salts listed in Table 4 below are the compound Nos. Of the exemplified compounds. Represents.

As shown in Table 4, it can be seen that the planographic printing plate precursors of Examples 22 to 28 have improved development latitude and stain resistance.
Further, in the comparison between Examples 1 to 7 and Examples 22 to 28, the planographic printing plate precursor using the photosensitive composition of the present invention for the recording layer is the same as in the case where the recording layer is a single layer or a multilayer. It was confirmed that the excellent effects of the present invention were exhibited.

Claims (2)

  (A) an infrared absorber, and (B) a compound having a triarylsulfonium salt structure and a sum of Hammett values of substituents bonded to the aryl skeleton being larger than 0.46. A positive photosensitive composition.   The compound (B) having a triarylsulfonium salt structure and having a sum of Hammett values of substituents bonded to the aryl skeleton greater than 0.46 is a Hammett value of substituents bonded to the aryl skeleton of triarylsulfonium. 2. The positive photosensitive composition according to claim 1, wherein the positive photosensitive composition is a compound comprising a cation having a sum total of greater than 0.46 and an anion having a hydrophilicity / hydrophobicity parameter logP of less than 2. 3.