JP4864682B2 - Polymerizable composition and planographic printing plate precursor using the same - Google Patents

Description

  The present invention relates to a polymerizable composition and a lithographic printing plate precursor using the polymerizable composition as a recording layer. More specifically, so-called direct plate-making is possible, which can be directly made from a digital signal of a computer or the like using an infrared laser. The present invention relates to a polymerizable compound suitably used as a recording layer of a negative negative lithographic printing plate precursor, and a lithographic printing plate precursor using the same.

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 region have been increasing in power and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.
The negative lithographic printing plate precursor for infrared laser that uses an infrared laser having a light emitting region in the infrared region as an exposure light source as described above performs image formation by using, for example, a photopolymerizable composition in the recording layer. ing.

  Conventionally, as a method for forming an image by exposure using a photopolymerizable composition, for example, a recording layer using a photopolymerizable composition containing an ethylenically unsaturated compound and a photopolymerization initiator is formed on the support surface. After forming and exposing the image to polymerize and cure the ethylenically unsaturated compound in the exposed area, the non-exposed area is dissolved and removed to form a cured relief image. The photopolymerizable composition layer (recording by exposure) Layer) and a method for forming an image by peeling the support after the adhesive strength to the support is changed, and an image using the change in toner adhesion due to light of the photopolymerizable composition layer Various methods such as a forming method are known. As photopolymerization initiators used in these methods, all have short wavelength light mainly in the ultraviolet region of 400 nm or less, such as benzoin, benzoin alkyl ether, benzyl ketal, benzophenone, anthraquinone, benzyl ketone, or Michler's ketone. Something that can respond to was used.

  On the other hand, in recent years, with the development of image forming technology, there is a strong demand for a photosensitive material exhibiting high sensitivity to light in the visible region. For example, it corresponds to a laser plate making method using an 488 nm oscillation beam of an argon ion laser. A number of photopolymerizable compositions having a sensitivity range of up to about 500 nm have been proposed. Furthermore, research on photopolymerizable compositions for light having a long wavelength region exceeding 600 nm has been actively conducted in response to a laser plate making system using a He-Ne laser or a semiconductor laser and a full-color image reproduction technique.

  Cyanine dye containing an ethylenically unsaturated compound and a photopolymerization initiating system as a photopolymerizable composition, the photopolymerization initiating system having a heterocyclic ring linked by a mono, tri, penta or heptamethine chain and having a specific structure And the technique containing the s-triazine derivative of a specific structure is known. (For example, refer to Patent Documents 1 and 2.) A photopolymerizable composition in which a polymerization initiator system is composed of a squarylium compound having a specific structure and a specific s-triazine compound has been proposed. (For example, refer to Patent Document 3.)

  However, the active radical generating ability of a photopolymerization initiator is usually sensitive to light with a wavelength of 500 nm or more, particularly light with a wavelength exceeding 600 nm, and the sensitivity rapidly decreases as the photoexcitation energy decreases. As described above, none of the photopolymerizable compositions conventionally proposed for light in such a long wavelength region is satisfactory in terms of sensitivity, and further under a white fluorescent lamp. There is also a problem that the photopolymerization reaction proceeds during handling, and it is difficult to obtain a stable quality.

  In the photopolymerizable composition as described above, an ethylenically unsaturated compound, a specific dye, and a photopolymerization initiator (triazine compound, etc.) Has been proposed (for example, see Patent Document 4). However, a lithographic printing plate using such a composition for the recording layer has low stability when stored in the printing plate, and it is eager to achieve high sensitivity while maintaining practically satisfactory stability. Has been.

In addition, a technique using an existing alkyl-substituted iodonium salt or monoalkoxy-substituted iodonium salt as a polymerization initiator in the photopolymerizable composition as described above has also been proposed. However, a lithographic printing plate using such a composition for the recording layer has high sensitivity, but there is a problem that the residual color becomes severe after development with time, and such a polymerization initiator is difficult to use.
Japanese Patent Laid-Open No. 58-29803 JP-A-4-31863 JP-A-4-106548 JP 2000-131837 A

An object of the present invention is to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide a highly sensitive polymerizable composition that has little sensitivity fluctuation, is stable even under severe storage conditions.
Another object of the present invention is to provide a lithographic printing plate precursor having excellent temporal stability using the polymerizable composition of the present invention as a recording layer.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using an iodonium salt and a specific mercapto compound, and have completed the present invention.

That is, the polymerizable composition of the present invention is selected from the group consisting of alkyl groups, alkoxy groups, amino groups, urea groups, alkoxyalkyl groups, acyloxyamino groups, cycloalkyl groups, and allyl groups in the molecule. A polymerization comprising: a diaryl iodonium salt having at least three electron donating groups, a compound having an ethylenically unsaturated double bond, and a mercapto compound represented by the following general formula (I): Composition.

  In general formula (I), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a membered ring or a six-membered heterocycle, and A may further have a substituent.

  The mercapto compound represented by the general formula (I) is at least one selected from the group consisting of a mercapto compound represented by the following general formula (II) and a mercapto compound represented by the general formula (III). Preferably there is.

  In general formula (II) or general formula (III), R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and X represents a halogen group or a substituent. Represents an alkoxy group which may have a substituent, an alkyl group which may have a substituent, or an aryl group which may have a substituent.

  The electron donating group possessed by the diaryliodonium salt is preferably an alkoxy group.

  More specifically, the diaryliodonium salt preferably has a partial structure represented by the following general formula (IV).

In general formula (IV), R ¹ , R ² and R ³ each independently represents an alkyl group or an aryl group.

Furthermore, the lithographic printing plate precursor according to the invention has a recording layer containing the polymerizable composition according to the invention.
The lithographic printing plate precursor according to the invention preferably further has a protective layer on the recording layer.

According to the present invention, it is possible to provide a polymerizable composition that is less sensitive to fluctuations in sensitivity, is stable even under severe storage conditions, and is highly sensitive.
Moreover, according to this invention, the lithographic printing plate precursor excellent in stability with time using the polymerizable composition of this invention as a recording layer can be provided.

Hereinafter, the polymerizable composition of the present invention and the planographic printing plate precursor using the same will be described in more detail.
[Polymerizable composition]
The polymerizable composition of the present invention has an electron donation selected from the group consisting of an alkyl group, an alkoxy group, an amino group, a urea group, an alkoxyalkyl group, an acyloxyamino group, a cycloalkyl group, and an allyl group in the molecule. It contains a diaryl iodonium salt having at least three functional groups, a compound having an ethylenically unsaturated double bond, and a mercapto compound represented by the following general formula (I).

In general formula (I), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a membered ring or a six-membered heterocycle, and A may further have a substituent.
Although the operation of the present invention is not yet clear, it is presumed as follows.
Although an iodonium salt having an excellent function as a polymerization initiator is excellent in polymerization sensitivity, it has a problem in stability and is difficult to use.
In the polymerizable composition of the present invention, it is considered that the chain pyrolysis reaction of the iodonium salt was suppressed by adding the mercapto compound even when the iodonium salt was contained as a polymerization initiator. Furthermore, by using a diaryl iodonium salt having 3 or more electron donating groups introduced as a polymerization initiator, decomposition of the iodonium salt compound with water or a nucleophile over time, or heat due to combination of pigments, etc. The electron transfer is suppressed, and as a result, it is considered that the stability of the polymerizable composition is improved while maintaining the sensitivity.
In general, a mercapto compound not only has a specific odor but is also volatile, and when in a photosensitive composition, the thiol compound evaporates or decomposes during long-term storage and functions effectively in the photosensitive composition. There was a problem that the amount to be reduced. In the present invention, it is presumed that the decomposition of the iodonium salt could be suppressed over a long period of time by using the mercapto compound having a specific structure.

The polymerizable composition of the present invention can be suitably used as a recording layer for a lithographic printing plate precursor.
Hereinafter, each component in the polymerizable composition of the present invention will be sequentially described. First, a description is a characteristic component in the present invention "mercapto compound represented by the general formula (I)" and details about the "electron-donating group in the molecule diaryl iodonium salt having at least three".

<Mercapto Compound Represented by General Formula (I)>
The polymerizable composition of the present invention contains a mercapto compound represented by the following general formula (I) (hereinafter referred to as “specific mercapto compound” as appropriate).

  In general formula (I), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a membered ring or a six-membered heterocycle, and A may further have a substituent.

The general formula (I) will be described in detail.
In general formula (I), as an alkyl group represented by R, a C1-C12 (preferably C1-C6, more preferably C1-C4) alkyl group is preferable.
The alkyl group represented by R may have a substituent, such as a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, Examples include an alkoxycarbonyl group, a carboxyl group, an amino group, an aryl group, an aryloxy group, a sulfo group, a thioalkoxy group, a urea group, and a urethane group.

In the general formula (I), the aryl group represented by R is preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group.
The aryl group represented by R may have a substituent, such as a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, Examples include an alkoxycarbonyl group, a carboxyl group, an amino group, an aryl group, an aryloxy group, a sulfo group, a thioalkoxy group, a urea group, and a urethane group.

  In the general formula (I), A represents an atomic group that forms a 5-membered or 6-membered heterocycle having a carbon atom together with the N═C—N moiety.

  The specific mercapto compound in the present invention is preferably at least one selected from the group consisting of a mercapto compound represented by the following general formula (II) and a mercapto compound represented by the general formula (III).

  In general formula (II) or general formula (III), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, X represents a halogen group, an alkoxy group, The alkyl group which may have a substituent, or the aryl group which may have a substituent is represented.

  In general formula (II) or general formula (III), the alkyl group which may have a substituent, or the aryl group which may have a substituent, represented by R, in general formula (I), It is synonymous with R, and its preferable range is also the same.

  In general formula (II) or general formula (III), as a halogen atom represented by X, a fluorine atom, a chlorine atom, and a bromine atom are mentioned.

  In general formula (II) or general formula (III), as an alkoxy group represented by X, a C1-C10 alkoxy group is preferable, a C1-C4 alkoxy group is preferable, especially a methoxy group and an ethoxy group. Groups are preferred.

  In general formula (II) or general formula (III), as an alkyl group represented by X, a C1-C12 (preferably C1-C6, more preferably C1-C4) alkyl group is mentioned. preferable. The alkyl group may have a substituent, and examples of the substituent include a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, an alkoxycarbonyl group, Examples thereof include a carboxyl group, an amino group, an aryl group, an aryloxy group, a sulfo group, a thioalkoxy group, a urea group, and a urethane group.

  In general formula (II) or general formula (III), as an aryl group represented by X, a phenyl group and a naphthyl group are preferable, and a phenyl group is especially preferable. The aryl group may have a substituent, and examples of the substituent include a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, an alkoxycarbonyl group, Examples thereof include a carboxyl group, an amino group, an aryl group, an aryloxy group, a sulfo group, a thioalkoxy group, a urea group, and a urethane group.

  Although the specific example of the specific mercapto compound in this invention is shown below, this invention is not limited to these.

  As content of the specific mercapto compound in the polymeric composition of this invention, 0.01-20 mass% is preferable with respect to the mass of the total solid which comprises polymeric composition, 0.1-15 mass% More preferably, 1.0-10 mass% is further more preferable.

<Diaryliodonium salt having three even less without an electron donating group>
The polymerizable composition of the present invention has an electron donation selected from the group consisting of an alkyl group, an alkoxy group, an amino group, a urea group, an alkoxyalkyl group, an acyloxyamino group, a cycloalkyl group, and an allyl group in the molecule. A diaryl iodonium salt having at least three functional groups (hereinafter referred to as “specific iodonium salt” as appropriate).

  In the present invention, the specific iodonium salt is contained as a polymerization initiator. This specific iodonium salt has a diaryl iodonium skeleton, and has at least three electron forcing groups in the skeleton, and is a compound excellent in reactivity and stability.

The electron donating group possessed by the specific iodonium salt is selected from the group consisting of an alkyl group, an alkoxy group, an amino group, a urea group, an alkoxyalkyl group, an acyloxyamino group, a cycloalkyl group, and an allyl group. In addition, an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, a thiol group, a thioalkoxy group, an amino group, a halogen atom or the like may be used as long as the electron donating property is not lost.
Preferred electron donating groups are preferably alkyl groups and alkoxy groups, and most preferred electron donating groups are alkoxy groups.

  Preferable substitution positions of the electron donating group with respect to the aryl skeleton are preferably the para position and the ortho position.

The number of substitutions of the electron donating group to be introduced is required to be at least 3 substitutions, and preferably 4 substitutions.
Preferable combinations of the electron donating group and the number of substitution include those having an alkoxy group as the electron donating group and having at least 3 substitutions, more preferably at least 4 substitutions.

As a physical property value when introducing an electron donating group, the sum of Hammett values of substituents introduced into the aryl skeleton is preferably −0.28 or less, more preferably −0.56 or less, Most preferably, it is -0.84 or less.
The Hammett value represents the degree of electron withdrawing property of the substituent in the diaryliodonium salt structure, and the Hammett value in the present invention is edited by the Chemical Society of Japan, Basic Chemistry Handbook II (1984, Maruzen Co., Ltd.). Reference can be made to the numerical values described in (Issuance).
The Hammett value is usually calculated with the values of the substitution positions at the m-th and p-th positions. In the present invention, as an electronic effect, the value at the o position is calculated as the same value as the value at the p position.

  Suitable specific iodonium salts that can be used in the present invention include iodonium salts having a partial structure represented by the following general formula (IV) in the molecule.

In general formula (IV), R ¹ , R ² and R ³ each independently represents an alkyl group or an aryl group.

R ¹ , R ² and R ³ may each further have a substituent, and examples of the substituent that can be introduced here include a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group. , Cycloalkenyl group, alkoxy group, alkoxycarbonyl group, carboxyl group, amino group, aryl group, aryloxy group, sulfo group, thioalkoxy group, urea group, urethane group and the like. From the viewpoint of stability, an alkyl group is preferred.

  The aromatic ring in the general formula (IV) may be substituted with other substituents such as a halogen atom, a hydroxyl group, an alkoxycarbonyl group, a carboxyl group, and an amide group as long as the effect of the electron donating group is not lost.

  In the partial structure represented by the general formula (IV), a more preferable structure includes a partial structure represented by the following general formula (IV-ii).

^R 1, ^{R 2} and ^{R 3} in the general formula (IV-ii) has the same meaning as ^R 1, ^{R 2} and ^{R 3} in the general formula (IV). R ⁴ is also synonymous with R ¹ , R ² and R ³ in the general formula (IV).

Regarding the counter anion of the specific iodonium salt in the present invention, any anion structure can be used without limitation.
Usable counter anions include carboxylate anion, sulfonate anion, sulfonamide anion, borate anion, phosphate anion, sulfinate anion, sulfate anion, PF ₆ ⁻ , BF ₄ ⁻ , SbF ₆ ⁻ , halogen anion, and the like. It is done. Among these, from the viewpoint of stability and sensitivity, an anion having a sulfonic acid group is preferable from the balance of stability and sensitivity.

  Specific examples [Exemplary compounds (IV-1) to (IV-28)] of specific iodonium salts that can be suitably used in the present invention are illustrated below, but the present invention is not limited thereto.

  Only 1 type may be used for the specific iodonium salt in a polymeric composition, and 2 or more types may be used together.

  The specific iodonium salt can be used in a proportion of 0.1 to 40% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the polymerizable composition. . When the content of the specific iodonium salt is within this range, better curing sensitivity and stability can be obtained.

  Further, when the polymerizable composition of the present invention is used as a recording layer of a lithographic printing plate precursor, good recording sensitivity is achieved, and due to its stability, good stain resistance of non-image areas during printing is difficult. Is obtained.

In addition to the specific iodonium salt, other known polymerization initiators can be used in combination with the polymerizable composition of the present invention as long as the effects of the present invention are not impaired.
Other polymerization initiators that can be used in combination include lophine dimer compounds, disulfone compounds, azo compounds, peroxide compounds, oxime ester compounds, haloalkyl compounds, triazine compounds, borate compounds, sulfonium salt compounds, iodonium salt compounds, diazonium salt compounds , Pyridinium salt compounds and the like can be used in combination.

In the polymerizable composition of the present invention, the total amount of the polymerization initiator in the case where the specific iodonium salt is used in combination with another polymerization initiator is 0.1 to 40% by mass with respect to the total solid content constituting the polymerizable composition. , Preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass.
The amount of other polymerization initiators that can be used in combination is preferably 50% by mass or less, more preferably 25% by mass or less, and more preferably 10% by mass or less, based on the total polymerization initiator. Most preferred.

When the polymerizable composition of the present invention is used as a recording layer of a lithographic printing plate precursor described later, a polymerization initiator containing a specific iodonium salt does not necessarily need to be contained in the recording layer. Even if the layer is provided and added thereto, the same effect can be obtained.
When a highly stable specific iodonium salt polymerization initiator, which is preferable as a polymerization initiator, is used for the recording layer of the lithographic printing plate precursor according to the invention, the radical polymerization reaction proceeds effectively, and the strength of the formed image area is very high. It will be expensive. Therefore, a lithographic printing plate having high image area strength can be produced, and as a result, printing durability is further improved. In addition, since the specific iodonium salt itself is excellent in stability over time due to the influence of the electron donating group, even when the prepared lithographic printing plate precursor is stored, an undesirable polymerization reaction is effectively generated. It also has the advantage of being suppressed.

-Other polymerization initiators that can be used together-
Other polymerization initiators that can be used in combination with the present invention will be described in more detail.
Other polymerization initiators that can be used in combination with the present invention are polymerization initiators other than the above-mentioned specific iodonium salts, which generate radicals by the energy of light, heat, or both, and have polymerizable unsaturated groups. A compound that initiates and accelerates the polymerization of the compound is used. As such a compound that generates radicals (radical generator), a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used. In the present invention, a compound that generates radicals refers to a compound that generates radicals by thermal energy and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As the thermal radical generator according to the present invention, a known polymerization initiator, a compound having a bond with a small bond dissociation energy, or the like can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types.

  Examples of the compound capable of generating radicals that can be used as a polymerization initiator in the present invention include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators (azo compounds), azide compounds, metallocene compounds, Examples include hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, oxime ester compounds, and onium salt compounds other than specific iodonium salts.

  Specific examples of the organic halogenated compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP 62 -212401, JP-A-63-70243, JP-A-63-298339, M.S. P. Hutt “Journal of Heterocyclic Chemistry” 1 (No 3), (1970) ”, and particularly, an oxazole compound substituted with a trihalomethyl group: an S-triazine compound.

  More preferably, an s-triazine derivative having at least one mono, di, or trihalogen-substituted methyl group bonded to the s-triazine ring, specifically, for example, 2,4,6-tris (monochloromethyl)- s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl)- s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, -(3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1 -(P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( p-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p -Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-natoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-pheni Thio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -S-triazine and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy-2 -Phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenylketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1-hydroxy -1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenyl) Acetophenone derivatives such as thioxanthone, thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, thioxanthone derivatives such as 2,4-diisopropylthioxanthone, p- Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide compound include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxide). Oxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroper Oxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2 , -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4 '-Tetra- (t-hexylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate) , Carbonyldi (t-hexylperoxydihydrogen diphthalate) and the like.

  Examples of the azide compound include organic azide compounds described in U.S. Pat. No. 2,848,328, U.S. Pat. No. 2,852,379 and U.S. Pat. No. 2,940,553, 2,6-bis (4-azidobenzylidene) -4-ethyl. And cyclohexanone (BAC-E).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di -Cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pentaful Lophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of hexaarylbiimidazole compounds include those described in JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. Various compounds, specifically 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl)) 4 , 4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis ( o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) biidazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetra Phenylbiimidazole 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5 Examples include '-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4', 5,5'-tetraphenylbiimidazole.

  Examples of the organic borate compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A-2000. -131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application No. 2000-310808, and Kunz, Martin “Rad Tech'98. Proceeding April 19-22, 1998, Chicago”. The organic borate described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, or organic boron oxosulfonium complex, JP-A-6-175554 No. 6, JP-A-6-175553 Organoboron iodonium complexes described in JP-A-9-188710, organoboron phosphonium complexes described in JP-A-9-348710, JP-A-7-128785, JP-A-7-140589, JP-A-7- Specific examples include organoboron transition metal coordination complexes such as those described in Japanese Patent No. 306527 and Japanese Patent Laid-Open No. 7-292014.

  Examples of the disulfone compound include compounds described in JP-A No. 61-166544 and Japanese Patent Application No. 2001-132318.

  Examples of oxime ester compounds include J.M. C. S. Perkin II (1979) 1653-1660), J. MoI. C. S. Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, JP-A 2000-66385, and JP-A 2000-80068. The compounds shown are mentioned.

Examples of the onium salt compounds that can be used in the present invention include onium salt compounds other than the specific iodonium salt among the onium salt compounds listed below.
For example, S.M. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in U.S. Pat. No. 4,069,055, ammonium salts described in JP-A-4-365049, U.S. Pat. No. 4,069, No. 055, No. 4,069,056, phosphonium salts described in European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049 and 410,201, JP -150848, JP-A-2-296514, European Patent Nos. 370,693, 390,214, 233,567, 297,443, 297,442, US Patent Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,734,444 , 2,833,827, German Patent 2,904,626, the 3,604,580 Patent, sulfonium salts described in the specification of Nos. 3,604,581, J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

  Examples of the onium salt used in the present invention include onium salts represented by the following general formulas (RI-I) to (RI-III). However, the onium represented by the general formula (RI-II) excludes those having the specific iodonium salt structure.

In General Formula (RI-I), Ar ¹¹ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms. Z11 ^- represents a monovalent anion, a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, surface stability To perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, and sulfinate ions.

In the general formula (RI-II), Ar ^{21 and} Ar ²² each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents have 1 to 12 carbon atoms. Alkyl group, alkenyl group having 1 to 12 carbon atoms, alkynyl group having 1 to 12 carbon atoms, aryl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryloxy group having 1 to 12 carbon atoms, halogen Atoms, alkylamino groups having 1 to 12 carbon atoms, dialkylamino groups having 1 to 12 carbon atoms, alkylamide groups or arylamide groups having 1 to 12 carbon atoms, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, carbon numbers A 1-12 thioalkyl group and a C1-C12 thioaryl group are mentioned. Z ^21- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, From the viewpoint of reactivity, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable.
However, the onium represented by the general formula (RI-II) excludes those having the specific iodonium salt structure.

In the general formula (RI-III), R ³¹ , R ³² , and R ³³ each independently represent an aryl group having a carbon number of 20 or less, an alkyl group, an alkenyl group, or an alkynyl group that may have 1 to 6 substituents. In view of reactivity and stability, an aryl group is desirable. Preferred substituents are alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, alkynyl groups having 1 to 12 carbon atoms, aryl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ^31- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, From the viewpoint of reactivity, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable. In particular, carboxylate ions described in JP-A No. 2001-343742 and carboxylate ions described in JP-A No. 2002-148790 are preferable, and carboxylate ions described in JP-A No. 2002-148790 are more preferable. preferable.

  Specific examples of onium salts that can be suitably used as polymerization initiators that can be used in combination in the polymerizable composition of the present invention are shown below, but are not limited thereto.

Examples of the polymerization initiator that can be used in combination with the present invention include oxime ester compounds, diazonium salts, iodonium salts other than specific iodonium salts, and sulfonium salts, particularly from the viewpoint of reactivity and stability. Among these, a sulfonium salt is more preferable from the viewpoints of sensitivity and thermal stability.
In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.

<Compound having an ethylenically unsaturated double bond>
The polymerizable composition of the present invention contains a compound having an ethylenically unsaturated double bond. The compound having an ethylenically unsaturated double bond (hereinafter also referred to as “polymerizable compound” as appropriate) is preferably an addition polymerizable compound having at least one ethylenically unsaturated double bond. , Preferably selected from the group of compounds having at least one terminal ethylenically unsaturated bond, preferably two or more.
Such compound groups are widely known in the industrial field, and these can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.

  Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, and JP-A-59-5240. Those having an aromatic skeleton described in JP-A-59-5241, JP-A-2-226149, and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.

  Examples of other preferable amide-based monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (i) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

^{_{CH 2 = C (R 51)}} COOCH 2 CH (R 52) OH (i)
(However, in General Formula (i), R ⁵¹ and R ⁵² represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable.

  Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 are also included. be able to. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, 30
Those introduced as photocurable monomers and oligomers on pages 0 to 308 (1984) can also be used.

About these compounds having an ethylenically unsaturated double bond, the details of the usage method such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final polymerizable composition .
For example, when the polymerizable composition of the present invention is used as a recording layer of a negative lithographic printing plate precursor, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether type). A method of adjusting both photosensitivity and intensity by using a compound) is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in photosensitive speed and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, selection and use of compounds having an ethylenically unsaturated double bond for compatibility and dispersibility with other components in the photosensitive layer (eg, binder polymer, polymerization initiator, colorant, etc.) Is an important factor. For example, compatibility may be improved by the use of a low-purity compound or a combination of two or more.

  Further, when the polymerizable composition in the present invention is applied as a recording layer of a lithographic printing plate precursor, a specific structure is used for the purpose of improving the adhesion of the support of the lithographic printing plate precursor and a protective layer described later. It can also be selected. Regarding the compounding ratio of the compound having an ethylenically unsaturated double bond in the recording layer, a larger amount is advantageous in terms of sensitivity, but if it is too much, an undesirable phase separation occurs, and the production due to the adhesiveness of the recording layer occurs. Problems such as process problems (for example, transfer of recording layer components, manufacturing defects due to adhesion) and precipitation from the developer may occur.

  From these viewpoints, the content of the polymerizable compound in the polymerizable composition of the present invention is the same as that when the polymerizable composition is applied to the recording layer of a lithographic printing plate precursor. The non-volatile component is preferably used in an amount of 5 to 80% by mass, more preferably 25 to 75% by mass. Moreover, the polymeric compound which concerns on this invention may be used independently, or may be used together 2 or more types. In addition, the polymerizable compound according to the present invention can be arbitrarily selected according to an appropriate structure, blending, and addition amount from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface tackiness, and the like. Furthermore, the lithographic printing plate precursor can also be used in a layer configuration and coating method such as an undercoat layer described later.

<Infrared absorber>
When the polymerizable composition of the present invention or a lithographic printing plate precursor in which the polymerizable composition is applied to a recording layer is exposed and cured by a laser that emits infrared light of 760 to 1200 nm, it is usually absorbed by infrared rays. It is preferable to use an agent.

  The infrared absorber has a function of converting the absorbed infrared light into heat and a function of being excited by the infrared light and transferring electrons / energy to the above-described polymerization initiator (specific iodonium salt, other polymerization initiator that can be used in combination). . The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. . Another example of a preferable dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.
Other preferred examples of the infrared absorbing dye of the present invention include specific indolenine cyanine dyes described in Japanese Patent Application Nos. 2001-6326 and 2001-237840 as exemplified below.

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

In the general formula (a), ^{X 1} represents a hydrogen atom, a halogen atom, -NPh2, a group shown X2-L1 or less. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L 1 represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 12 carbon atoms including a hetero atom. Represents a hydrocarbon group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. X ^a- is defined in the same manner as Z ^1- described later, and Ra represents a substituent selected from a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, and a halogen atom.

In general formula (a), R ¹ and R ² each independently represent 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 or It is particularly preferable that a 6-membered ring is formed.

In the general formula (a), Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred substituents include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, an alkoxy group having 12 or less carbon atoms, a hydrocarbon group having 12 or less carbon atoms, and 12 carbon atoms. Most preferred are not more than alkoxy groups. Y1 and Y2 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. Preferable substituents include an alkoxy group having 12 or less carbon atoms, a carboxyl group, and a sulfo group, and an alkoxy group having 12 or less carbon atoms is most preferable. 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. However, ^Za- is not necessary when the cyanine dye represented by formula (i) has an anionic substituent in its structure and neutralization of charge 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, in view of storage stability of the recording layer coating solution. Tetrafluoroborate ion, hexafluorophosphate ion, and aryl sulfonate ion.

Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in Japanese Patent Application Nos. 2001-6326 and 2001-237840 described above.

  Examples of pigments that can be used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

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

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

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within this range, good stability of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording layer can be obtained.

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

  In a lithographic printing plate precursor to which the polymerizable composition of the present invention is applied as a recording layer (lithographic printing plate precursor of the present invention), when the lithographic printing plate precursor is prepared, the recording layer has a maximum in the wavelength range of 760 nm to 1200 nm. It is added so that the absorbance at the absorption wavelength is in the range of 0.3 to 1.2 by the reflection measurement method. Preferably, it is the range of 0.4-1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the recording layer, and good film strength of the image area and adhesion to the support can be obtained. In the lithographic printing plate precursor, the infrared absorber may be provided with another layer other than the recording layer. The absorbance of the recording layer can be adjusted by the amount of the infrared absorber added to the recording layer and the thickness of the recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

<Binder polymer>
When the polymerizable composition of the present invention is applied to the recording layer of a lithographic printing plate precursor as a preferred embodiment thereof, it has a polymerization initiator containing the above-described specific iodonium salt and an ethylenically unsaturated double bond. It is preferable to use a binder polymer in addition to the compound.

The binder polymer that can be contained in the polymerizable composition of the present invention is a polymer that functions as a film-forming agent for the recording layer, and preferably contains a linear organic polymer. Any such “linear organic polymer” may be used.
As an example of such a binder polymer, a polymer selected from an acrylic resin, a polyvinyl acetal resin, a polyurethane resin, a polyamide resin, an epoxy resin, a methacrylic resin, a styrene resin, and a polyester resin is preferable. Of these, acrylic resins and polyurethane resins are preferable.

Further, the binder polymer can be cross-linked in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the course of radical polymerization reaction that occurs in the recording layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

In the general formula (1), R ^{1 to} R ³ each independently represents a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom and a methyl group are preferable because of high radical reactivity. R ²
, R ³ each independently has a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group that may have a substituent, or a substituent. An aryl group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an aryl which may have a substituent Examples include an amino group, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among which a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, and a substituent. Preferred alkyl groups and aryl groups which may have a substituent are preferred because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2), R ^{4 to} R ⁸ each independently represents a monovalent organic group, but R ⁴
To R ⁸ is preferably a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent Arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent may be mentioned. The alkyl group which may have and the aryl group which may have a substituent are preferable.

Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R < ¹² > is synonymous with the case of R < ¹² > of General formula (1), and its preferable example is also the same.

In the general formula (3), R ⁹ is preferably a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group is preferable because of high radical reactivity. . R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group that may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, a substituent An arylamino group that may have, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Z represents an oxygen atom, a sulfur atom, -N (R ¹³ )-, or an optionally substituted phenylene group. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol.

-Alkali-soluble binder polymer-
In the embodiment in which the development treatment applied to the lithographic printing plate precursor according to the present invention is performed using an alkali developer, the binder polymer needs to be dissolved in the alkali developer, and thus is soluble or swellable in alkali water. An organic high molecular polymer is preferably used. In particular, when an alkali developer having a pH of 10 or more is used, an alkali-soluble binder is preferably used. In order to be soluble in alkaline water, it preferably has an alkali-soluble group. The alkali solubility is preferably an acid group, and examples thereof include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a hydroxyl group. Among these, a binder polymer having a carboxyl group is particularly preferable from the viewpoint of achieving both film properties, counter-printing properties, and developability.

  Furthermore, the alkali-soluble binder polymer can be cross-linked as described above in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  The weight average molecular weight of the alkali-soluble binder polymer is appropriately determined from the viewpoints of image forming properties and printing durability in the lithographic printing plate precursor. A preferred weight average molecular weight is in the range of 2,000 to 1,000,000, more preferably 5,000 to 500,000, and still more preferably 10,000 to 200,000. Moreover, it is preferable that a number average molecular weight is 1000 or more, and it is more preferable that it is 2000-250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The alkali-soluble binder polymer may be any of a random polymer, a block polymer, a graft polymer and the like, but is preferably a random polymer.
The alkali-soluble binder polymer may be used alone or in combination of two or more.
The content of the alkali-soluble binder polymer is usually 5 to 90% by mass, preferably 10 to 70% by mass, and more preferably 10 to 60% by mass with respect to the total solid content of the recording layer. . Within this range, good image area strength and image formability can be obtained.

  Moreover, as an alkali-soluble binder polymer suitable in this invention, it is a binder polymer which has a repeating unit represented by following General formula (4). Hereinafter, the binder polymer having the repeating unit represented by the general formula (4) will be referred to as a specific binder polymer, and will be described in detail.

In General Formula (4), R ¹ represents a hydrogen atom or a methyl group, and R ² includes two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. And represents a linking group having 2 to 82 total atoms. A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. n represents an integer of 1 to 5.

R ¹ in the general formula (4) represents a hydrogen atom or a methyl group, and a methyl group is particularly preferable.
The linking group represented by R ² in the general formula (4) includes two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. The number is 2 to 82, preferably 2 to 50, and more preferably 2 to 30. The total number of atoms shown here refers to the number of atoms including the substituent when the linking group has a substituent. More specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1-30, more preferably 3-25, and 4-20. More preferred is 5-10. In addition, the “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the general formula (4), and particularly when there are a plurality of linking paths. Refers to an atom or atomic group that constitutes a path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

More specific examples include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond may be used.
Examples of the linking group having a chain structure include ethylene and propylene. A structure in which these alkylenes are linked via an ester bond can also be exemplified as a preferable example.

Among these, the linking group represented by R ² in the general formula (4) is preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. More specifically, a compound having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, dicyclohexyl, tercyclohexyl, norbornane and the like, which may be substituted by one or more arbitrary substituents And (n + 1) valent hydrocarbon groups by removing (n + 1) hydrogen atoms on an arbitrary carbon atom constituting. R ² preferably has 3 to 30 carbon atoms including a substituent.

One or more arbitrary carbon atoms of the compound constituting the aliphatic cyclic structure may be replaced with a heteroatom selected from a nitrogen atom, an oxygen atom, or a sulfur atom. In terms of printing durability, R ² is a condensed polycyclic aliphatic hydrocarbon, a bridged cyclic aliphatic hydrocarbon, a spiro aliphatic hydrocarbon, an aliphatic hydrocarbon ring assembly (a plurality of rings are connected by a bond or a linking group). A (n + 1) valent hydrocarbon group having an aliphatic cyclic structure which may have a substituent of 5 to 30 carbon atoms containing two or more rings. . Also in this case, the carbon number includes the carbon atom of the substituent.

As the linking group represented by R ² , those having 5 to 10 atoms constituting the main skeleton of the linking group are particularly preferable, and are structurally a chain structure, and an ester bond in the structure. And those having a cyclic structure as described above are preferred.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. Group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N- Diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy Group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′- Arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N '-Alkyl-N-arylureido group, N', N'-dialkyl-N-alkylureido group, N ', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N '-Aryl-N-arylureido group, N', N'-diaryl-N-alkylureido group, N ', N'-diaryl-N-arylureido group, N'-a Kill-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group and its conjugate base group, Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, Alkylsulfinyl , An arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (-SO 3 _H) and its conjugated base group, alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group, N- alkylsulfinamoyl group, N, N -Dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group , N- alkylsulfonylsulfamoyl group _(-SO 2 NHS ₂ (alkyl)) and its conjugated base group, N- aryl sulfonylsulfamoyl group _{(-SO 2 NHSO 2 (aryl)} ) and its conjugated base group, N- alkylsulfonylcarbamoyl group _(-CONHSO 2 _(alkyl)) and Its conjugated base group, N-arylsulfonylcarbamoyl group (—CONHSO ₂ (aryl)) and its conjugated base group, alkoxysilyl group (—Si (Oalkyl) ₃ ), aryloxysilyl group (—Si (Oaryl) ₃ ), Hydroxysilyl group (—Si (OH) ₃ ) and its conjugate base group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (—PO ₃ (alkyl) ₂ ), diarylphosphono group (—PO ₃ (aryl) ₂ ), alkylarylphosphono group (—PO ₃ (a lkyl) (aryl)), monoalkylphosphono group (—PO ₃ H (alkyl)) and its conjugate base group, monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group, phosphonooxy group ( -OPO ₃ H ₂₎ and its conjugated base group, a dialkyl phosphono group _{(-OPO 3 (alkyl) 2)} , diaryl phosphono group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphono group (- _{OPO 3 (alkyl) (aryl)} ), monoalkyl phosphono group _(-OPO 3 H _(alkyl)) and its conjugated base group, monoarylphosphono group _(-OPO 3 H _(aryl)) and its conjugate base group, a cyano group, a nitro group, a dialkyl boryl group (-B _{(alkyl) 2),} Jiariruboriru group (-B ( _RYL) 2), alkyl aryl boryl group (-B (alkyl) (aryl) ), dihydroxy boryl group (-B _{(OH) 2)} and its conjugated base group, an alkyl hydroxy boryl group (-B (alkyl) (OH) ) And its conjugated base group, arylhydroxyboryl group (-B (aryl) (OH)) and its conjugated base group, aryl group, alkenyl group and alkynyl group.

  When the polymerizable composition of the present invention is applied to the recording layer of a lithographic printing plate precursor, depending on the design of the recording layer, the substituent having a hydrogen atom capable of hydrogen bonding, particularly an acid rather than a carboxylic acid. Substituents having an acidity with a small dissociation constant (pKa) are not preferred because they tend to lower the printing durability. On the other hand, hydrophobic substituents such as halogen atoms, hydrocarbon groups (alkyl groups, aryl groups, alkenyl groups, alkynyl groups), alkoxy groups, aryloxy groups and the like are more preferable because they tend to improve printing durability. When the cyclic structure is a monocyclic aliphatic hydrocarbon having 6 or less members such as cyclopentane or cyclohexane, it preferably has such a hydrophobic substituent. If possible, these substituents may be bonded to each other or with a substituted hydrocarbon group to form a ring, and the substituent may be further substituted.

R ³ in the case where A in formula (4) is NR ³ — represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.

  Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, 1 carbon number such as tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Up to 10 linear, branched or cyclic alkyl groups.

Specific examples of the aryl group include carbon having one heteroatom selected from the group consisting of an aryl group having 1 to 10 carbon atoms such as a phenyl group, a naphthyl group, and an indenyl group, a nitrogen atom, an oxygen atom, and a sulfur atom. Examples include heteroaryl groups of 1 to 10, such as furyl, thienyl, pyrrolyl, pyridyl, and quinolyl groups.
Specific examples of the alkenyl group include those having 1 to 10 carbon atoms such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like. A linear, branched, or cyclic alkenyl group is mentioned.

Specific examples of the alkynyl group include alkynyl groups having 1 to 10 carbon atoms such as ethynyl group, 1-propynyl group, 1-butynyl group, and 1-octynyl group. The substituent that R ³ may have is the same as those exemplified as the substituent that R ² can introduce. The number of carbon atoms of ^{R 3} is 1 to 10 including the carbon number of the substituent.
A in the general formula (4) is preferably an oxygen atom or —NH— because synthesis is easy.

N in the general formula (4) represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.
Although the preferable specific example of the repeating unit represented by General formula (4) below is shown, this invention is not limited to these.

  Only one type of repeating unit represented by the general formula (4) may be contained in the binder polymer, or two or more types may be contained. The specific binder polymer in the present invention may be a polymer composed only of the repeating unit represented by the general formula (4), but is usually used as a copolymer in combination with other copolymerization components. The total content of the repeating unit represented by the general formula (4) in the copolymer is appropriately determined depending on the structure, the design of the polymerizable composition, and the like, but preferably 1 to 99 with respect to the total molar amount of the polymer component. It is contained in the range of mol%, more preferably 5 to 40 mol%, still more preferably 5 to 20 mol%.

  As a copolymerization component in the case of using as a copolymer, a conventionally well-known thing can be used without a restriction | limiting if it is a monomer which can be radically polymerized. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of such copolymerization component may be used, or two or more types may be used in combination.

  The binder polymer used in the present invention may be a specific binder polymer alone, or may be used as a mixture by combining one or more other binder polymers. The binder polymer used in combination is used in the range of 1 to 80% by mass, preferably 1 to 40% by mass, and more preferably 1 to 20% by mass with respect to the total mass of the binder polymer component. As the binder polymer that can be used in combination, a conventionally known binder polymer can be used without limitation, and specifically, an acrylic main chain binder, a urethane binder, or the like often used in the industry is preferably used. Furthermore, those having a polymerizable group often used in the industry are preferred, and those having an acidic group are preferred.

Although the total amount of the specific binder polymer in the polymerizable composition and the binder polymer that may be used in combination can be appropriately determined, it is generally 10 to 90 with respect to the total mass of the nonvolatile components in the photosensitive layer composition. It is mass%, Preferably it is 20-80 mass%, More preferably, it is the range of 30-70 mass%.
Moreover, as an acid value (meq / g) of such a binder polymer, it is preferable that it is the range of 2.00-3.60.

<Other ingredients>
To the polymerizable composition of the present invention, other components suitable for its use, production method and the like can be appropriately added. Hereinafter, preferable additives will be described.
(1) Co-sensitizer The sensitivity can be further improved by using certain additives in the polymerizable composition. Such a compound is hereinafter referred to as a co-sensitizer. These mechanisms of action are not clear, but many are thought to be based on the following chemical processes. That is, the photosensitivity initiated by the thermal polymerization initiator and the various intermediate active species (radicals and cations) generated during the subsequent addition polymerization reaction react with the co-sensitizer to generate new active radicals. Presumed to be. These can be broadly divided into (i) those that can be reduced to generate active radicals, (ii) those that can be oxidized to generate active radicals, and (iii) radicals that react with less active radicals and have higher activity. Can be classified into those that act as chain transfer agents, but there is often no generality as to which of these individual compounds belong.

(I) Compound that is reduced to generate an active radical Compound having a carbon-halogen bond: It is considered that an active radical is generated by reductive cleavage of the carbon-halogen bond. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.
Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that an oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.
Ferrocene and iron arene complexes: An active radical can be reductively generated.

(Ii) Compound that is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.
Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines , N-phenyliminodiacetic acid and derivatives thereof, and N-trimethylsilylmethylanilines.
Sulfur-containing and tin-containing compounds: those in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.

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

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

In addition, for the purpose of improving sensitivity and / or developability, a polycarboxylic acid having an aromatic ring or a heteroaromatic ring structure and having at least two carboxyl groups bonded thereto directly or via a divalent linking group. It is also a preferable aspect to contain an acid compound. Specific examples of such polycarboxylic acid compounds include (p-acetamidophenylimide) diacetic acid, 3- (bis (carboxymethyl) amino) benzoic acid, and 4- (bis (carboxymethyl) amino) benzoic acid. Acid, 2-[(carboxymethyl) phenylamino] benzoic acid, 2-[(carboxymethyl) phenylamino] -5-methoxybenzoic acid, 3- [bis (carboxymethyl) amino] -2-naphthalenecarboxylic acid, N -(4-aminophenyl) -N- (carboxymethyl) glycine, N, N'-1,3-phenylenebisglycine, N, N'-1,3-phenylenebis [N- (carboxymethyl)] glycine, N, N′-1,2-phenylenebis [N- (carboxymethyl)] glycine, N- (carboxymethyl) -N- (4-methoxyphenyl) Nyl) glycine, N- (carboxymethyl) -N- (3-methoxyphenyl) glycine, N- (carboxymethyl) -N- (3-hydroxyphenyl) glycine, N- (carboxymethyl) -N- (3- Chlorophenyl) glycine, N- (carboxymethyl) -N- (4-bromophenyl) glycine, N- (carboxymethyl) -N- (4-chlorophenyl) glycine, N- (carboxymethyl) -N- (2-chlorophenyl) ) Glycine, N- (carboxymethyl) -N- (4-ethylphenyl) glycine, N- (carboxymethyl) -N- (2,3-dimethylphenyl) glycine, N- (carboxymethyl) -N- (3 , 4-Dimethylphenyl) glycine, N- (carboxymethyl) -N- (3,5-dimethylphenyl) glycine, N- Carboxymethyl) -N- (2,4-dimethylphenyl) glycine, N- (carboxymethyl) -N- (2,6-dimethylphenyl) glycine, N- (carboxymethyl) -N- (4-formylphenyl) Glycine, N- (carboxymethyl) -N-ethylanthranilic acid, N- (carboxymethyl) -N-propylanthranilic acid, 5-bromo-N- (carboxymethyl) anthranilic acid, N- (2-carboxyphenyl) glycine O-dianisidine-N, N, N ′, N′-tetraacetic acid, N, N ′-[1,2-ethanediylbis (oxy-2,1-phenylene)] bis [N- (carboxymethyl) glycine], 4-carboxyphenoxyacetic acid, catechol-O, O'-diacetic acid, 4-methylcatechol-O, O'-diacetic acid, resorcinol-O, O'- Diacetic acid, hydroquinone-O, O′-diacetic acid, α-carboxy-o-anisic acid, 4,4′-isopropylidenediphenoxyacetic acid, 2,2 ′-(dibenzofuran-2,8-diyldioxy) diacetic acid, Examples include 2- (carboxymethylthio) benzoic acid, 5-amino-2- (carboxymethylthiobenzoic acid, 3-[(carboxymethyl) thio] -2-naphthalenecarboxylic acid, and the like.
Especially, the compound represented by the N-aryl polycarboxylic acid represented by the following general formula (A) or general formula (B) is preferable.

  In general formula (A), Ar represents a mono-, poly- or unsubstituted aryl group, and m represents an integer of 1 to 5. Here, examples of the substituent that can be introduced into the aryl group include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a thioalkyl group having 1 to 3 carbon atoms, and a halogen atom. The aryl group preferably has 1 to 3 identical or different substituents. m is preferably 1, and Ar preferably represents a phenyl group.

In General Formula (B), R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and n and p each represent an integer of 1 to 5. n is preferably ¹ , and R ¹ is preferably a hydrogen atom. The most preferred polycarboxylic acid is anilinodiacetic acid.

Other preferable compounds for improving sensitivity and / or improving developability are compounds having at least either a carboxylic acid group or a sulfonic acid group, or more specifically, 5-aminoisophthalic acid, 5-nitro Isophthalic acid, 4-methylphthalic acid, terephthalic acid, 2-bromoterephthalic acid, 2,3-naphthalenedicarboxylic acid, diphenic acid, 1,4,5,8-naphthalenetetracarboxylic acid, N-benzyliminodiacetic acid, N- (2-carboxyphenylglycine), N-phenyliminodiacetic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, 5-sulfosalicylic acid, 2-sulfobenzoic acid, 1 , 5-naphthalenedisulfonic acid, 4-sulfophthalic acid and the like. The above compound is further substituted with an alkyl group, alkenyl group, alkynyl group, cyano group, halogen atom, hydroxyl group, carboxyl group, carbonyl group, alkoxy group, amino group, amide group, thiol group, thioalkoxy group, sulfonyl group. May be.
Among these, the most preferable is a compound represented by the general formula (A) or the general formula (B).
The amount of the poly (carboxylic acid / sulfonic acid) compound added is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass in the solid content before the polymerizable composition. 3 to 8% by mass is particularly preferable.

More specific examples of these cosensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity, and these are also applied to the present invention. can do.
These co-sensitizers can be used alone or in combination of two or more. The amount used is 0.05 to 100 parts by mass, preferably 1 to 80 parts by mass, and more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the compound having an ethylenically unsaturated double bond.

(2) Polymerization inhibitor In the present invention, in addition to the basic components described above, a small amount of heat is used to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the composition used for the recording layer. It is desirable to add a polymerization inhibitor. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the entire composition. In addition, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition due to oxygen, and a lithographic printing plate precursor is dried after coating on a support or the like. In this process, it may be unevenly distributed on the surface of the recording layer. The amount of the higher fatty acid derivative added is preferably about 0.5% by mass to about 10% by mass of the total composition.

(3) Colorant etc. Furthermore, you may add dye or a pigment to the polymeric composition of this invention for the purpose of coloring. As a result, if the polymerizable composition of the present invention is applied to the recording layer of a lithographic printing plate precursor, it improves the so-called plate inspection properties such as visibility after plate making and suitability for image density measurement as a printing plate. Can be made.
As the colorant, many dyes cause a decrease in the sensitivity of the photopolymerization recording layer. Therefore, it is particularly preferable to use a pigment as the colorant. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the dye and the pigment is preferably about 0.5% by mass to about 5% by mass of the total composition.

(4) Other additives Furthermore, when the polymerizable composition of the present invention is applied to the recording layer of a lithographic printing plate precursor, an inorganic filler for improving the physical properties of the cured film, other plasticizers, You may add well-known additives, such as a fat-sensitizing agent which can improve the ink inking property of the recording layer surface.

  Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin, and a binder was used. In this case, 10% by mass or less can be added with respect to the total mass of the compound having an ethylenically unsaturated double bond and the binder.

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

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has a recording layer containing the polymerizable composition according to the invention. Hereinafter, the layer structure of the lithographic printing plate precursor according to the invention will be described.

<Recording layer>
For the recording layer in the lithographic printing plate precursor according to the invention, a recording layer coating solution (polymerizable composition of the invention) in which the components constituting the recording layer are dissolved in a solvent is prepared, and the recording layer coating solution is used as a suitable support. It can form by apply | coating on.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl. Ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether Diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate and so on. These solvents can be used alone or in combination. The solid content in the coating solution is suitably 2 to 50% by mass.

The coating amount of the recording layer on the support is preferably selected according to the intended use in consideration of the sensitivity of the recording layer, the developability, the strength of the exposed film and the printing durability. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. The coating amount of the lithographic printing plate precursor according to the present invention is generally about 0. 0 by weight after drying. A range of 1 to about 10 g / m ² is suitable. More preferably from 0.5 to 5 g / ^{m 2.}

<Protective layer>
The lithographic printing plate precursor according to the invention preferably further has a protective layer on the recording layer. Hereinafter, the protective layer will be described in detail.
It is desirable that the protective layer does not substantially inhibit the transmission of light used for exposure, has excellent adhesion to the recording layer, and can be easily removed in a development process after exposure. Various devices relating to such a protective layer have been conventionally used, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-A-55-49729. Such a protective layer can also be applied to the lithographic printing plate precursor according to the invention.

  In addition, since the lithographic printing plate precursor in the present invention has a polymerization type recording layer, it is desirable to have an oxygen blocking ability that blocks oxygen in the atmosphere and exhibits a polymerization inhibiting action during exposure. On the other hand, it is also desirable to have an oxygen permeation ability that exhibits an effect of preventing dark polymerization from the viewpoint of stability during storage or suitability for safelight, and a protective layer having a low oxygen barrier property to the extent that it has both functions. Is desirable.

-Water-soluble polymer compounds-
As a material used as a main component for the protective layer, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic Water-soluble polymers such as polyacrylic acid are well known in the art. Of these, the use of polyvinyl alcohol as the main component gives the best results for basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having the required oxygen barrier properties and water solubility. . Similarly, it may be a copolymer partially having other repeating units.

  Specific examples of water-soluble polymer compounds include PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, manufactured by Kuraray Co., Ltd. PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA- 224E, PVA-405, PVA-420, PVA-613, L-8 and the like. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof. Other useful water-soluble polymer compounds include polyvinylpyrrolidone, gelatin and gum arabic, and these may be used alone or in combination.

  Examples of the polyvinyl alcohol suitably used include those having a saponification degree of 71 to 100% and a molecular weight of 200 to 2400. It is more preferable to use polyvinyl alcohol having a saponification degree of 91 mol% or more from the viewpoint of good oxygen barrier properties, excellent film forming properties and a low adhesion surface.

  A commercial item can also be used as polyvinyl alcohol. Specific examples of commercially available polyvinyl alcohol include PVA-102, PVA-103, PVA-104, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, manufactured by Kuraray Co., Ltd. PVA-117H, PVA-135H, PVA-HC, PVA-617, PVA-624, PVA-706, PVA-613, PVA-CS, PVA-CST, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol NL-05, NM-11, NM-14, AL-06, P-610, C-500, A-300, AH-17, JV-04, JF-05, JF-10, manufactured by Nippon Vinegar Poval Co., Ltd. JF-17, JF-17L, JM-05, JM-10, JM-17, JM-17L, JT-05, JT-13, JT-15, etc. That.

Furthermore, what acid-modified polyvinyl alcohol is also used suitably. Specifically, itaconic acid and maleic acid-modified carboxy-modified polyvinyl alcohol and sulfonic acid-modified polyvinyl alcohol are preferable. These acid-modified polyvinyl alcohols having a saponification degree of 91 mol% or more can be more preferably used.
Specific examples of the acid-modified polyvinyl alcohol include KL-118, KM-618, KM-118, SK-5102, MP-102, R-2105, manufactured by Kuraray Co., Ltd., and Nippon Synthetic Chemical Industry Co., Ltd. , GOHSENAL CKS-50, T-HS-1, T-215, T-350, T-330, T-330H, AF-17, AT-17, etc. manufactured by Nihon Ventures & Poval Co., Ltd. are included.

  In consideration of the sensitivity of the obtained lithographic printing plate precursor and the suppression of adhesion between the lithographic printing plate precursors when the lithographic printing plate precursors are laminated, the water-soluble polymer compound is based on the total solid content in the protective layer. It is preferable to contain in 45-95 mass%, and it is more preferable to contain in 50-90 mass%.

  Further, at least one water-soluble polymer compound may be used in the protective layer, and a plurality of water-soluble polymer compounds may be used in combination. Even when a plurality of types of water-soluble polymer compounds are used in combination, the total amount is preferably in the above-described mass range.

  On the other hand, in the protective layer, the adhesion of the recording layer to the image portion and the uniformity of the film are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic recording layer, film peeling due to insufficient adhesive force is likely to occur, and the peeled portion causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563 disclose an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and the like and laminating on the recording layer. Of course, any of these known techniques can be applied.

  Polyvinyl alcohol and polyvinyl pyrrolidone may be used in combination in the protective layer from the viewpoints of adhesive strength with the recording layer, sensitivity, and generation of unnecessary fog. In this case, the addition ratio (mass ratio) of polyvinyl alcohol / polyvinylpyrrolidone having a saponification degree of 91 mol% or more is preferably 3/1 or less. In addition to polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and copolymers thereof having relatively excellent crystallinity can be used in combination with polyvinyl alcohol.

-Filler-
In addition to the water-soluble polymer compound, the protective layer according to the present invention preferably contains a filler. By containing a filler, scratch resistance on the surface of the recording layer can be improved, and furthermore, adhesion between adjacent lithographic printing plate precursors that occurs when lithographic printing plate precursors are laminated without interleaving is suppressed. In addition, the releasability between the lithographic printing plate precursors can be made excellent, so that the handling property is also improved. As such a filler, any of an organic filler, an inorganic filler, an inorganic-organic composite filler, and the like may be used, and two or more of these may be mixed and used. Preferably, an inorganic filler and an organic filler are used in combination.

  The shape of the filler is appropriately selected depending on the purpose, but for example, fibrous, needle-like, plate-like, spherical, granular (herein, “granular” refers to “indefinitely shaped particles”, hereinafter, In the present specification, they are used in the same meaning.), Tetrapot shape, balloon shape and the like. Of these, preferred are plate-like, spherical and granular.

  Examples of the organic filler include synthetic resin particles, natural polymer particles, and the like, and preferably acrylic resin, polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, polyethyleneimine, polystyrene, polyurethane, polyurea, polyester, polyamide, polyimide, Resin particles such as carboxymethyl cellulose, gelatin, starch, chitin, and chitosan, and more preferably resin particles such as acrylic resin, polyethylene, polypropylene, and polystyrene.

  Specific examples of commercially available fillers suitable for the organic filler added to the protective layer include Chemipearl W100, W200, W300, W308, W310, W400, W401, W4005, W410, W500, WF640, and W700 manufactured by Mitsui Chemicals. W800, W900, W950, WP100, manufactured by Soken Chemical Co., Ltd., MX-150, MX-180, MX-300, MX-500, MX-1000, MX-1500H, MX-2000, MR-2HG, MR-7HG, MR-10HG, MR-3GSN, MR-5GSN, MR-2G, MR-7G, MR-10G, MR-20G, MR-5C, MR-7GC, SX-130H, SX-350H, SX-500H, SGP- 50C, SGP-70C, MBX-5, MBX-8, MBX made by Sekisui Plastics 12, MBX-15, MBX-20, MB20X-5, MB30X-5, MB30X-8, MB30X-20, SBX-6, SBX-8, SBX-12, SBX-17, and the like.

  The particle size distribution may be monodisperse or polydisperse, but monodispersion is preferred. The filler preferably has an average particle size of 1 to 20 μm, more preferably an average particle size of 2 to 15 μm, and still more preferably an average particle size of 3 to 10 μm. By setting it within these ranges, the effect of the present invention is more effectively expressed.

  The content of the organic filler is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and further preferably 2 to 10% by mass with respect to the total solid content of the protective layer.

Inorganic fillers include metals and metal compounds such as oxides, composite oxides, hydroxides, carbonates, sulfates, silicates, phosphates, nitrides, carbides, sulfides and at least two of these. Specific examples include the above composites, specifically, mica compounds, glass, zinc oxide, alumina, zircon oxide, tin oxide, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, magnesium borate, aluminum hydroxide , Magnesium hydroxide, calcium hydroxide, titanium hydroxide, basic magnesium sulfate, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, calcium silicate, magnesium silicate, calcium phosphate, silicon nitride, titanium nitride, aluminum nitride, carbonized Silicon, titanium carbide, zinc sulfide and at least of these It includes species or more composite products, such as.
Preferably, mica compound, glass, alumina, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium phosphate, calcium sulfate and the like can be mentioned.
Of these, mica compounds are particularly suitable for the protective layer. The inorganic layered compound represented by this mica will be described in detail below.

-Inorganic layered compounds-
The protective layer according to the present invention preferably contains an inorganic layered compound. By using an inorganic stratiform compound in combination, the oxygen barrier property is further increased, and the film strength of the protective layer is further improved to improve scratch resistance, and matte properties can be imparted to the protective layer.
As a result, the protective layer can suppress deterioration due to deformation or the like and generation of scratches in addition to the above-described barrier property against oxygen or the like. Furthermore, when a lithographic printing plate precursor is laminated by imparting a matte property to the protective layer, adhesion between the protective layer surface of the lithographic printing plate precursor and the back surface of the adjacent lithographic printing plate precursor is suppressed. Is possible.

Examples of the inorganic layered compound include, for example, a general formula: A (B, C) ₂ -5D ₄ O ₁₀ (OH, F, O) ₂ [where A is any of K, Na, Ca, B and C Is one of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica compounds such as natural mica and synthetic mica.

In the mica compound, examples of natural mica include muscovite, soda mica, phlogopite, biotite, and sericite. In addition, examples of the synthetic mica include non-swelling mica such as fluorine phlogopite mica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 (Si ₄ O ₁₀ ) F ₂ , and Na tetrasilic mica. NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li Teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite Na or Li Hectorite (Na, Li) _1/8 Examples thereof include swellable mica such as Mg _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ . In addition, synthetic smectites are also useful.

Of the mica compounds, fluorine-based swellable mica is particularly useful. That is, this swellable synthetic mica has a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and the substitution of metal atoms in the lattice is significantly larger than other viscosity minerals. As a result, the lattice layer is deficient in positive charge, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swellable synthetic mica has a strong tendency and is useful in the present embodiment. In particular, swellable synthetic mica is preferably used.

  The shape of the mica compound is preferably as small as possible from the viewpoint of diffusion control, and the plane size is preferably as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured from, for example, a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the mica compound is 0.3 to 20 μm, preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. Specifically, for example, the swellable synthetic mica that is a representative compound has a thickness of 1 to 50 nm and a surface size (major axis) of about 1 to 20 μm.

The amount contained in the protective layer of the inorganic stratiform compound is from the viewpoint of suppression of adhesion between lithographic printing plate precursors when they are laminated, suppression of scratches, sensitivity reduction due to blocking during laser exposure, low oxygen permeability, etc. The total solid content of the protective layer is preferably in the range of 5 to 50% by mass, particularly preferably in the range of 10 to 40% by mass. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass.
Similarly, the amount contained in the protective layer of the inorganic filler other than the inorganic layered compound is also preferably in the range of 5 to 50% by mass, and in the range of 10 to 40% by mass with respect to the total solid content of the protective layer. Particularly preferred.

In the protective layer, an organic filler and an inorganic filler can be mixed and used, and the mixing ratio is preferably in a range of 1: 1 to 1: 5 by weight. As content to the protective layer in this case, it is preferable that it is the range of 5-50 mass% by the total amount of an inorganic filler organic filler with respect to the total solid content of a protective layer, and the range of 10-40 mass% is preferable. More preferred.
An inorganic-organic composite filler can also be used. Examples of the inorganic-organic composite filler include composites of the above organic filler and inorganic filler. Examples of the inorganic filler used for the composite include metal powders, metal compounds (for example, oxides, nitrides, sulfides). , Carbides and composites thereof), preferably oxides and sulfides, more preferably glass, SiO ₂ , ZnO, Fe ₂ O ₃ , ZrO ₂ , SnO ₂ , ZnS, CuS. And the like. As content to the protective layer of an inorganic-organic composite filler, it is preferable that it is the range of 5-50 mass% with respect to the total solid content of a protective layer, and the range of 10-40 mass% is more preferable.

Components of the protective layer (selection of polyvinyl alcohol and inorganic layered compounds, use of additives), coating amount, etc. are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability The
In the present invention, the protective layer is not limited to a single layer, and a plurality of protective layers having different compositions can be provided in a multilayer structure. As a preferred embodiment of the protective layer having a multilayer structure, a protective layer containing an inorganic layered compound is provided as a lower protective layer in the vicinity of the recording layer, and a protective layer containing a filler on the surface thereof is used as an upper protective layer. The aspect which laminates sequentially is mentioned.
By providing a protective layer having such a laminated structure, the uppermost protective layer has the excellent oxygen barrier properties and compatibility with the lower protective layer while fully utilizing the advantages of scratch resistance and adhesion resistance due to the filler. Thus, it is possible to effectively prevent image defects due to both the generation of scratches and undesired oxygen permeation.
The protective layer in the present invention has an oxygen permeability of 0.5 ml / m ² · at 25 ° C.-1 atm.
The amount is preferably not less than day and not more than 100 ml / m ² · day, and the coating amount is preferably adjusted so as to achieve such oxygen permeability.

  The protective layer may be added with a colorant (water-soluble dye) that is excellent in the transparency of light used when exposing the recording layer and that can efficiently absorb light having a wavelength that is not related to exposure. Good. Thereby, safelight aptitude can be improved, without reducing a sensitivity.

-Formation of protective layer-
The method for applying the protective layer is not particularly limited, and is carried out by applying an aqueous protective layer coating solution containing the above components on the recording layer. For example, the method described in US Pat. No. 3,458,311 or JP-A-55-49729 can also be applied.

  Hereinafter, a method for applying a protective layer containing an inorganic layered compound such as a mica compound and a water-soluble polymer compound such as polyvinyl alcohol will be described in detail. A dispersion in which an inorganic layered compound such as a mica compound is dispersed is prepared, and the dispersion is mixed with a water-soluble polymer compound such as polyvinyl alcohol (or an aqueous solution in which a water-soluble polymer compound is dissolved). The protective layer is formed by applying the protective layer coating liquid formed on the recording layer.

  An example of a method for dispersing an inorganic layered compound such as a mica compound used in the protective layer will be described. First, 5 to 10 parts by mass of the swellable mica compound mentioned above as a preferable mica compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. In general, a 2 to 15% by mass dispersion of the mica compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a coating solution for a protective layer using this dispersion, after diluting with water and stirring sufficiently, a water-soluble polymer compound such as polyvinyl alcohol (or a water-soluble polymer compound such as polyvinyl alcohol) is added. It is preferable to prepare by blending with a dissolved aqueous solution.

  Known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the resulting film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, a known additive for improving the adhesion to the recording layer and the temporal stability of the coating solution may be added to the coating solution.

The coating amount of the protective layer is 0.1 g / m ² to 4 in terms of maintaining the film strength and scratch resistance of the protective layer to be obtained, maintaining the image quality, and maintaining appropriate oxygen permeability for imparting safelight suitability. 0.0 g / m ² is preferable, and 0.3 g / m ^{2 to} 3.0 g / m ² is more preferable.

The protective layer may be a single layer or a multilayer structure. There is no particular limitation on the coating method in the case of providing a protective layer having a multilayer structure, and either a method of simultaneous multilayer coating or a method of sequential coating and multilayering can be applied.
When performing multi-layer coating, the coating amount of the upper protective layer containing a lower protective layer and the filler containing an inorganic stratiform compound, the lower protective layer is 0.1g ^/ m ² ~1.5g / m 2 preferably , more preferably ^{0.2g / m 2 ~1.0g / m 2} , the upper protective layer is preferably ^{0.1g / m 2 ~4.0g / m 2} , 0.2g / m 2 ~3.0g / m ² is more preferable. The balance between the two is preferably 1: 1 to 1: 5.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, an undercoat layer (also referred to as an intermediate layer) made of an alkali-soluble polymer can be provided between the recording layer and the support, if necessary.

By having the undercoat layer, the recording layer is provided on the exposed surface or in the vicinity thereof, so that the sensitivity to an infrared laser or the like is improved, and the undercoat layer exists between the support and the recording layer, and the heat insulating layer As a result, the heat generated by the infrared laser exposure is not diffused to the support, and the sensitivity can be increased because it is used efficiently.
In the exposed area, the photosensitive layer (recording layer) that has become impermeable to the alkali developer functions as a protective layer for the undercoat layer. It is considered that an excellent image is formed and the stability over time is ensured. In the unexposed area, the uncured binder component quickly dissolves and disperses in the developer. The undercoat layer that is adjacent to the surface is made of an alkali-soluble polymer, so the solubility in the developer is good.For example, even when a developer with reduced activity is used, a residual film is generated. Therefore, it is considered that the developability is excellent.

<Support>
As the support in the present invention, it is preferable to use a support subjected to a hydrophilization treatment as described later. Examples of such a support include paper, polyester film, and aluminum plate. Among them, a surface having good dimensional stability, relatively inexpensive, and excellent hydrophilicity and strength by surface treatment as required. An aluminum plate that can be provided is more preferred. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  The aluminum plate as the most preferable support in the present invention is a metal plate mainly composed of dimensionally stable aluminum. In addition to a pure aluminum plate, an alloy mainly composed of aluminum and containing a trace amount of foreign elements. A plate or aluminum (alloy) is selected from laminated or vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or aluminum alloy is used generically as an aluminum support.

  Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.

Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's desire.
Such an aluminum support is subjected to a surface treatment described later to be hydrophilized.

−Roughening treatment−
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, an electrochemical surface roughening method in which the surface of the aluminum surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte, and the aluminum surface is ground with a metal wire, and the aluminum brush surface is polished with a polishing ball and an abrasive. A mechanical graining method such as a pole grain method, a brush grain method in which the surface is roughened with a nylon brush and an abrasive, can be used, and the above roughening methods can be used alone or in combination. Among them, a method usefully used for roughening is an electrochemical method in which roughening is chemically roughened in hydrochloric acid or nitric acid electrolyte, and a suitable anodic electricity is 50 C / dm ^{2 to} 400 C /
It is in the range of dm ^2. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, alternating at a current density of 100C ^/ dm ² ~400C ^/ dm 2 It is preferable to perform direct current electrolysis.

  The roughened aluminum support may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, and the like. Preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C. Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123. After the treatment as described above, the method and conditions are not particularly limited as long as the surface roughness Ra of the treated surface is about 0.2 to 0.5 μm.

-Anodizing treatment-
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions and the like, and the concentration is 0 to 10,000 ppm. May be included. There are no particular limitations on the conditions of the anodizing treatment, but the treatment is preferably carried out by direct current or alternating current electrolysis at a treatment liquid temperature of 10 to 70 ° C. and a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter. . The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. Preferably it is the range of 0.5-1.0 micrometer. The support produced by the above treatment is treated so that the pore diameter of the micropores existing in the anodized film is in the range of 5 to 10 nm and the pore density is in the range of 8 × 10 ¹⁵ to 2 × 10 ¹⁶ pieces / m ^2. It is preferred that the conditions are selected.

A widely known method can be applied as the hydrophilic treatment of the support surface. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. The coating is formed with a Si or P element amount of ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The coating amount can be measured by fluorescent X-ray analysis.

  In the hydrophilization treatment, an anodized film is formed in an aqueous solution containing 1 to 30% by mass, preferably 2 to 15% by mass of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. For example, it is carried out by immersing the aluminum support thus obtained at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or Group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. A surface obtained by combining a support subjected to electrolytic grain as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 with the above-described anodizing treatment and hydrophilization treatment. Processing is also useful.

-Backside treatment of support-
In the lithographic printing plate precursor according to the invention, the back surface of the support is preferably modified for the purpose of further improving scratch resistance. As a method for modifying the back surface of the support, for example, when an aluminum support is used, a method of uniformly forming an anodic oxide film on the entire back surface as in the recording layer side or a back coat layer is formed on the back surface. The method of doing is mentioned. The film-forming amount in the case of taking a method of forming an anodic oxide film, is preferably 0.6 g / ^{m 2} or more, preferably in the range of 0.7~6g / ^{m 2.} Of these, a method of providing a backcoat layer is more effective and preferable. Hereinafter, these back surface processing methods will be described.

(1) Method for Forming Back Anodic Oxide Film First, a method for uniformly forming an anodized film on the entire back surface of the aluminum support in the same manner as the recording layer side at 0.6 g / m ² or more will be described. The formation of the anodized film is performed by the same means as described in the support surface treatment. The thickness of the anodized film provided on the back surface of the support is effective if it is 0.6 g / m ² or more, and the upper limit is not particularly limited from the viewpoint of performance. Considering energy, time required for formation, etc., it may be about 6 g / m ² , and a practical preferable film amount is 0.7 g to 6 g / m ² , and a more preferable range is 1.0 g to 3 g / m ^2. a m ^2.
The amount of the anodic oxide film can be converted by measuring the peak of Al ₂ O ₃ using fluorescent X-rays and using a calibration curve of the peak height and the film amount.

In the present invention, the anodic oxide film is provided on the entire surface of the aluminum support, and the amount thereof is 0.6 g / m ² or more. The center part of the surface having the oxide film, and the end part 5 cm from both ends in the direction (Transverse Direction) passing through the center part and orthogonal to the processing direction (Machine Direction) are both 0.6 g of anodic oxide film amount. / M ² or more.

(2) Method for Forming Backcoat Layer Next, a method for providing a backcoat layer on the back surface of the aluminum support will be described. As the back coat layer in the present invention, any composition may be used, and in particular, a metal oxide obtained by hydrolysis and polycondensation of an organometallic compound or an inorganic metal compound described in detail below. A back coat layer comprising a colloidal silica sol or a back coat layer comprising an organic resin film is preferred.
(2-1) Backcoat layer containing metal oxide and colloidal silica sol A preferred first embodiment of the backcoat layer in the present invention is a backcoat layer containing a metal oxide and colloidal silica sol.
More specifically, it is formed by a so-called sol-gel reaction solution in which an organometallic compound or an inorganic metal compound is hydrolyzed with a catalyst such as an acid or alkali in a water and an organic solvent, and a polycondensation reaction is caused. A backcoat layer is preferred.
Examples of the organic metal compound or inorganic metal compound used for forming the back coat layer include metal alkoxide, metal acetylacetonate, metal acetate, metal oxalate, metal nitrate, metal sulfate, metal carbonate, metal oxychloride. , Metal chlorides, and condensates obtained by oligomerizing these by partial hydrolysis.
The metal alkoxide is represented by a general formula of M (OR) _n (M is a metal element, R is an alkyl group, and n is an oxidation number of the metal element). As specific examples, for example, Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ , Al (OCH ₃ ) ₃ , Al ( OC ₂ H ₅ ) ₃ , Al (OC ₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , B (OCH ₃ ) ₃ , B (OC ₂ H ₅ ) ₃ , B (OC ₃ H ₇ ) ₃ , B (OC ₄ H ₉ ) ₃ , Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Zr (OCH ₃ ) ₄ , Zr (OC ₂ H ₅ ) ₄ , Zr (OC ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) _{4 and the} like can be mentioned. In addition, for example, Ge, Li, Na, Fe, Ga, Mg, P , Alkoxides such as Sb, Sn, Ta, and V. In addition, mono-substituted silicon such as CH ₃ Si (OCH ₃ ) ₃ , C ₂ H ₅ Si (OCH ₃ ) ₃ , CH ₃ Si (OC ₂ H ₅ ) ₃ , C ₂ H ₅ Si (OC ₂ H ₅ ) ₃ Alkoxides are also used.

These organic metal compounds or inorganic metal compounds can be used alone or in combination of two or more. Among these organometallic compounds or inorganic metal compounds, metal alkoxides are preferable because they are highly reactive and easily form a polymer made of a metal-oxygen bond. Among them, silicon alkoxide compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , and Si (OC ₄ H ₉ ) ₄ are inexpensive and easily available. The coating layer of the metal oxide obtained therefrom is excellent and particularly preferred. Also preferred are oligomers obtained by condensing these silicon alkoxide compounds by partial hydrolysis. An example of this is an average pentamer ethylsilicate oligomer containing about 40% by weight of SiO ₂ .

Furthermore, it is also preferable to use a so-called silane coupling agent in which one or two alkoxy groups of the silicon tetraalkoxy compound are substituted with an alkyl group or a reactive group in combination with these metal alkoxides. As the silane coupling agent to be added to the backcoat layer in the present invention, one or two alkoxy groups in the silicon tetraalkoxy compound may be a hydrophobic group such as a long-chain alkyl group having 4 to 20 carbon atoms or a fluorine-substituted alkyl group. Examples include silane coupling agents substituted with a substituent, and silane coupling agents having a fluorine-substituted alkyl group are particularly preferable. Specific examples of such a silane coupling agent include CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , CF ₃ CF ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , CF ₃ CH ₂ CH ₂ Si (OC). ₂ H ₅ ) _{3 and the} like, and commercially available products include LS-1090 manufactured by Shin-Etsu Chemical Co., Ltd. The silane coupling agent substituted with the fluorine-substituted alkyl group is included in the organic fluorine compound in the present invention. The preferable content of such a silane coupling agent is 5 to 90% by mass, more preferably 10 to 80% by mass, based on the total solid content of the backcoat layer.

  As a catalyst useful when forming a sol-gel coating solution for the backcoat layer, organic and inorganic acids and alkalis are used. Examples include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, fluorine, phosphoric acid, phosphorous acid and other inorganic acids, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, Fluoroacetic acid, bromoacetic acid, methoxyacetic acid, oxaloacetic acid, citric acid, oxalic acid, succinic acid, malic acid, tartaric acid, fumaric acid, maleic acid, malonic acid, ascorbic acid, benzoic acid, 3,4-dimethoxybenzoic acid Substituted benzoic acid, phenoxyacetic acid, phthalic acid, picric acid, nicotinic acid, picolinic acid, pyrazine, pyrazole, dipicolinic acid, adipic acid, p-toluic acid, terephthalic acid, 1,4-cyclohexene-2,2-dicarboxylic acid , Erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and other organic acids, alkali metals and alkaline earths Genus hydroxide, ammonia, ethanolamine, diethanolamine, and alkali such as triethanolamine.

  Other preferred catalysts include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, and phosphate esters, such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl acid. Organic acids such as phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, and diphenyl phosphate can also be used.

  These catalysts can be used alone or in combination of two or more. The catalyst is preferably from 0.001 to 10% by mass, more preferably from 0.05 to 5% by mass, based on the starting metal compound. If the amount of the catalyst is less than this range, the start of the sol-gel reaction is delayed, and if it is more than this range, the reaction proceeds rapidly and non-uniform sol-gel particles are formed. Become.

  In order to initiate the sol-gel reaction, an appropriate amount of water is further required, and the preferred amount of addition is preferably 0.05 to 50 times the amount of water required to completely hydrolyze the starting metal compound. More preferably, it is 0.5 to 30 times mol. If the amount of water is less than this range, the hydrolysis is difficult to proceed, and if it is more than this range, the reaction is difficult to proceed because the raw material is diluted.

A solvent is further added to the sol-gel reaction solution. Any solvent may be used as long as it dissolves the starting metal compound and dissolves or disperses the sol-gel particles produced by the reaction, such as lower alcohols such as methanol, ethanol, propanol, and butanol, acetone, methyl ethyl ketone, diethyl ketone, and the like. Ketones are used. In addition, mono- or dialkyl ethers and acetates of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol can be used for the purpose of improving the coating surface quality of the backcoat layer. Of these solvents, lower alcohols that are miscible with water are preferred. The sol-gel reaction solution is prepared with a solvent at a concentration suitable for coating. However, if the total amount of the solvent is added to the reaction solution from the beginning, the raw material is diluted, making it difficult for the hydrolysis reaction to proceed. Therefore, a method of adding a part of the solvent to the sol-gel reaction solution and adding the remaining solvent when the reaction proceeds is preferable.
The coating amount of the back coat layer containing the metal oxide thus formed and the colloidal silica sol is preferably 0.01 to 3.0 g / m ² and preferably 0.03 to 1.0 g / m 2. ² is more preferable.

(2-2) Backcoat layer comprising an organic resin film Another preferred example of the backcoat layer in the present invention is a backcoat layer comprising an organic resin film formed on the back surface of the support.
Examples of a preferable resin that can form the backcoat layer in this embodiment include thermosetting resins such as urea resin, epoxy resin, phenol resin, melamine resin, and diallyl phthalate resin. Among these, from the viewpoint that the physical strength of the layer to be formed is high, a phenol resin is preferable, and more specifically, for example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m− / p. Preferred examples include novolak resins and pyrogallol acetone resins such as mixed cresol formaldehyde resins and phenol / cresol (which may be either m-, p-, or m- / p-mixed) mixed formaldehyde resins.

Further, as the phenol resin, as described in US Pat. No. 4,123,279, an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is further used. Examples thereof include a condensation polymer of phenol and formaldehyde as a substituent.
The phenol 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 phenol 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 organic compound 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 You may use resin etc. together.

A surfactant can be added to the backcoat layer for the purpose of improving the coating surface properties and controlling the surface properties. The surfactant used here is an anionic surfactant having any of carboxylic acid, sulfonic acid, sulfate ester and phosphate ester; a cationic surfactant such as aliphatic amine, quaternary ammonium salt. Agents: Betaine-type amphoteric surfactants; or nonionic surfactants such as fatty acid esters of polyoxy compounds, polyalkynelene oxide condensation type, polyethyleneimine condensation type, and fluorine surfactants. A fluorochemical surfactant is preferred.
The addition amount of the surfactant is appropriately selected according to the purpose, but in general, it can be added in the range of 0.1 to 10.0% by mass in the back coat layer.

As the fluorine-based surfactant, a fluorine-based surfactant containing a perfluoroalkyl group in the molecule is particularly preferable. Such a fluorinated surfactant will be described in detail.
Fluorosurfactants that can be particularly preferably used in the backcoat layer include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates, and amphoteric such as perfluoroalkyl betaines. Type, cationic type such as perfluoroalkyltrimethylammonium salt and perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, perfluoroalkyl group and hydrophilic group-containing oligomer, perfluoroalkyl group and lipophilic group-containing oligomer, perfluoro Nonionic types such as alkyl group, hydrophilic group and lipophilic group-containing oligomer, perfluoroalkyl group and lipophilic group-containing urethane are included. Among these, the fluoroaliphatic group is preferably a group represented by the following general formula (C).

In general formula (C), R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and X is a divalent group selected from a single bond, an alkylene group, an arylene group, and the like. , M represents an integer of 0 or more, and n represents an integer of 1 or more.
Here, when X represents a divalent linking group, the linking group such as an alkylene group or an arylene group may have a substituent, and the structure includes an ether group, an ester group, an amide group. It may have a linking group selected from a group and the like. Examples of the substituent that can be introduced into the alkylene group or arylene group include a halogen atom, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these may further have a substituent. Good. Among these, X is preferably an alkylene group, an arylene group, or an alkylene group having a linking group selected from an ether group, an ester group, an amide group, and the like, an unsubstituted alkylene group, an unsubstituted arylene group, or An alkylene group having an ether group or an ester group inside is more preferable, and an unsubstituted alkylene group or an alkylene group having an ether group or an ester group inside is most preferable.
It is preferable to contain about 0.5 to 10% by mass of such a fluorosurfactant in the backcoat layer.

  Various methods can be applied to cover the back surface of the aluminum support with the backcoat layer made of an organic resin film. After adding fine particles such as silica gel to the backcoat layer components, specifically, organic resin as the main ingredient, if desired, for example, dissolved in an appropriate solvent or prepared as an emulsified dispersion to prepare a coating solution Then, it is applied to the back side of the support and dried, or an organic resin film previously formed into a film shape is bonded to the aluminum support via an adhesive or by heating, and a molten film is formed with a melt extruder. And a method of bonding to a support. Among these, the most preferable method from the viewpoint of easy control of the coating amount is a method of coating and drying the solution. As the solvent used here, an organic solvent as described in JP-A-62-251739 is used alone or in combination.

  Examples of means for applying the backcoat layer coating solution to the support surface include a bar coater, a roll coater, a gravure coater, a known coater, such as a curtain coater, an extruder, and a slide hopper. Non-contact quantitative coaters such as curtain coaters, extruders, slide hoppers, etc. are particularly preferred from the viewpoint of not scratching the surface.

The thickness of the back coat layer is such that the formed film thickness is in the range of 0.1 to 8 μm in both the back coat layer containing the metal oxide and the colloidal silica sol and the back coat layer made of an organic resin. preferable. In this thickness range, the surface slipperiness of the back surface of the aluminum support is improved, and during printing, the thickness variation due to dissolution and swelling of the backcoat layer by chemicals used around the printing, and the printing pressure resulting therefrom Can suppress the deterioration of the printing characteristics due to the change.
The most preferable backcoat layer is a backcoat layer made of an organic resin.

<Plate making method>
Hereinafter, an example of the plate making method of the lithographic printing plate precursor according to the invention will be described.
As the plate making method of the lithographic printing plate precursor according to the present invention, for example, the lithographic printing plate precursor according to the present invention described above is described with a protective layer and a support (in the following description of the plate making method, an aluminum support is used as an example. ) After setting the laminated body formed by laminating a plurality of sheets in direct contact with the back surface in a plate setter and automatically transporting the lithographic printing plate precursor one by one, after exposure processing at a wavelength of 750 nm to 1400 nm, There is a method in which the development processing is performed under the condition that the conveyance speed is 1.25 m / min or more without substantially undergoing the heat treatment.

Even if the planographic printing plate precursor of the present invention is laminated without interposing the interleaf, the adhesion between the planographic printing plate precursors and the generation of scratches on the protective layer are suppressed. It can be applied to the plate making method.
Further, according to the plate making method as described above, since a laminated body in which planographic printing plate precursors are laminated without interposing the interleaving paper is used, it is unnecessary to remove the interleaving paper, and productivity in the plate making process is improved.

  The recording layer (photosensitive layer) to which the lithographic printing plate making method described above is applied has a development rate of 80 nm / sec or more in an unexposed area with respect to an alkaline developer having a pH of 10 to 13.5, and the alkali development. It is preferable that the penetration rate of the liquid at the exposed portion is 50 nF / sec or less. The method for measuring the developing speed of the unexposed portion of the recording layer and the penetration speed of the alkali developer into the photosensitive layer after curing is the method described in Japanese Patent Application No. 2004-248535 previously filed by the present applicant. Can be used. Control of the development speed of the unexposed portion of the recording layer and the penetration speed of the alkali developer with respect to the photosensitive layer after curing can be performed by a conventional method, but a typical method is to use the specific binder polymer. In addition, the addition of a hydrophilic compound is useful for improving the developing speed of the unexposed area, and the means for adding a hydrophobic compound is useful for suppressing the penetration of the developer into the exposed area.

-Exposure-
The light source used in the exposure process applied to the lithographic printing plate precursor according to the present invention may be any light source as long as it can be exposed at a wavelength of 750 nm to 1400 nm, and an infrared laser is preferable. In particular, in the present invention, image exposure is preferably performed with a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 750 nm to 1400 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . If the exposure energy is too low, the photosensitive layer is not sufficiently cured. If the exposure energy is too high, the photosensitive layer may be laser ablated and the image may be damaged.

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

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

  In the present invention, as described above, the exposed lithographic printing plate precursor is subjected to a development process without performing a special heat treatment and water washing treatment. By not performing this heat treatment, image non-uniformity due to the heat treatment can be suppressed. Further, by performing neither heat treatment nor water washing treatment, stable high-speed processing is possible in the development processing.

-Development-
In the development processing applied to the present invention, the non-image portion of the recording layer is removed using a developer.
In the present invention, as described above, the processing in the development processing speed, i.e., the conveying speed of the lithographic printing plate precursor in the development process (line speed) is preferably a this is 1.25 m / min or more, more preferably Is 1.35 m / min or more. Moreover, there is no restriction | limiting in particular in the upper limit of a conveyance speed, However, From a viewpoint of stability of conveyance, it is preferable that it is 3 m / min or less.
Hereinafter, the developer used in the present invention will be described.

<Developer>
The developer used in the present invention is preferably an alkaline aqueous solution having a pH of 14 or less, and preferably contains an aromatic anionic surfactant.

-Aromatic anionic surfactant-
Aromatic anionic surfactants have a development accelerating effect and a dispersion stabilizing effect in a developing solution of a polymerizable negative photosensitive layer component and a protective layer component, and are preferable in developing processing stabilization. Among them, the aromatic anionic surfactant used in the present invention is preferably a compound represented by the following general formula (D) or general formula (E).

The general formula (D) or the general formula (E) will be described in detail.
R ¹ and R ³ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, and specific examples include an ethylene group, a propylene group, a butylene group, a pentylene group, Among these, an ethylene group and a propylene group are particularly preferable.
m and n each independently represent an integer selected from 1 to 100. Among them, 1 to 30 are preferable, and 2 to 20 are more preferable. When m is 2 or more, a plurality of R ¹ may be the same or different. Similarly, when n is 2 or more, a plurality of R ³ may be the same or different.
t and u each independently represents 0 or 1.

R ² and R ⁴ each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, hexyl group, dodecyl group Among them, a methyl group, an ethyl group, an iso-propyl group, an n-propyl group, an n-butyl group, an iso-butyl group, and a tert-butyl group are particularly preferable.
p and q each represent an integer selected from 0 to 2; Y ¹ and Y ² each represent a single bond or an alkylene group having 1 to 10 carbon atoms. Specifically, a single bond, a methylene group or an ethylene group is preferred, and a single bond is particularly preferred.
(Z ¹ ) ^{r +} and (Z ² ) ^{s +} each independently represent an alkali metal ion, an alkaline earth metal ion, or an ammonium ion that is unsubstituted or substituted with an alkyl group. Sodium ion, potassium ion, magnesium ion, calcium ion, ammonium ion, secondary to quaternary ammonium ion substituted with an alkyl group, aryl group, or aralkyl group in the range of 1 to 20 carbon atoms, etc. In particular, sodium ion is preferable. r and s each represent 1 or 2.

  Specific examples of the aromatic anionic surfactant are shown below, but the present invention is not limited thereto.

  These aromatic anionic surfactants may be used alone or in appropriate combination of two or more. The amount of the aromatic anionic surfactant added is preferably such that the concentration of the aromatic anionic surfactant in the developer is in the range of 1.0 to 10% by mass, more preferably in the range of 2 to 10% by mass. It is effective to do. Here, if the content is less than 1.0% by mass, the developability and the solubility of the photosensitive layer components may be reduced. If the content exceeds 10% by mass, the printing durability of the printing plate may be reduced. There is a concern to reduce.

In addition to the aromatic anionic surfactant, other surfactants may be used in combination with the developer. Examples of other surfactants include polyoxyethylene naphthyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, Polyoxyethylene alkyl esters such as oxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan triesterate and other sorbitan alkyl esters, glycerol mono Nonionic surfactants such as monoglyceride alkyl esters such as stearate and glycerol monooleate.
The content of these other surfactants in the developer is preferably from 0.1 to 10% by mass in terms of active ingredients.

-Chelating agents for bivalent metals-
For example, the developer preferably contains a chelating agent for a divalent metal in order to suppress the influence of calcium ions contained in hard water. Examples of chelating agents for divalent metals include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , Calgon (polymetalin). Polyphosphates such as ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, its amine salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino-2 -Propanol tetraacetic acid 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salt, sodium salt thereof; 2-phosphonobutanone tricarboxylic acid-2, in addition to aminopolycarboxylic acids such as potassium salt, sodium salt, etc. 3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid-1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, Examples thereof include organic phosphonic acids such as aminotri (methylenephosphonic acid), potassium salt, sodium salt, and the like. Among them, ethylenediaminetetraacetic acid, potassium salt, sodium salt, amine salt; ethylenediamine; Tetra (methylenephosphonic acid), its ammonium salt, its potash Salt; hexamethylenediamine tetra (methylene phosphonic acid), an ammonium salt, its potassium salt is preferred.
The optimum amount of such a chelating agent varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by mass, more preferably 0% in the developing solution at the time of use. It is made to contain in the range of 0.01-0.5 mass%.

  Further, an alkali metal salt of an organic acid or an alkali metal salt of an inorganic acid may be added to the developer as a development regulator. For example, sodium carbonate, potassium, ammonium, sodium citrate, potassium, ammonium and the like may be used alone or in combination of two or more.

-Alkaline agent-
Examples of the alkali agent used in the developer include inorganic alkalis such as tribasic sodium phosphate, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, potassium, ammonium, and lithium. And monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanol Examples include organic alkali agents such as noramine, ethyleneimine, ethylenediamine, pyridine, and tetramethylammonium hydroxide. In the present invention, these may be used alone or in combination of two or more.

  Moreover, alkali silicate can be mentioned as alkali agents other than the above. Alkali silicates may be used in combination with a base. The alkali silicate to be used exhibits alkalinity when dissolved in water, and examples thereof include sodium silicate, potassium silicate, lithium silicate, and ammonium silicate. These alkali silicates may be used alone or in combination of two or more.

The developer used in the present invention includes silicon oxide SiO ₂ which is a silicate component as a hydrophilizing component of a support, and alkali oxide M ₂ O as an alkali component (M represents an alkali metal or ammonium group). By adjusting the mixing ratio and concentration, it can be easily adjusted to the optimum range. Mixing ratio of silicon oxide SiO ₂ and alkali oxide M ₂ O (SiO ₂ /
M ₂ O (molar ratio) suppresses the generation of insoluble gas due to leaving soil due to excessive dissolution (etching) of the support anodic oxide film and complex formation between dissolved aluminum and silicate. From the viewpoint of, for example, it is preferably in the range of 0.75 to 4.0, more preferably in the range of 0.75 to 3.5.

In addition, the alkali silicate concentration in the developer includes the effect of inhibiting dissolution (etching) of the anodic oxide film on the support, the developability, the effect of inhibiting precipitation and crystal formation, and the gelation during neutralization during waste From the viewpoint of the prevention effect and the like, the amount of SiO _{2 with} respect to the mass of the developing solution
˜1 mol / L is preferable, and more preferably 0.05 to 0.8 mol / L.

  In the developer, in addition to the above components, the following components may be used in combination as required. For example, benzoic acid, phthalic acid, p-ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, pt-butylbenzoic acid Acids, p-2-hydroxyethylbenzoic acid, decanoic acid, salicylic acid, organic carboxylic acids such as 3-hydroxy-2-naphthoic acid; organic solvents such as propylene glycol; other reducing agents, dyes, pigments, water softeners And preservatives.

  The developer preferably has a pH in the range of 10 to 12.5 at 25 ° C, and more preferably in the range of pH 11 to 12.5. Since the developer contains the surfactant, even if such a low pH developer is used, excellent developability is exhibited in the non-image area. Thus, by setting the pH of the developing solution to a relatively low value, damage to the image area during development is reduced and the handling property of the developing solution is excellent.

The conductivity x of the developer is preferably 2 <x <30 mS / cm, and more preferably 5 to 25 mS / cm.
Here, it is preferable to add an alkali metal salt of an organic acid, an alkali metal salt of an inorganic acid, or the like as a conductivity adjusting agent for adjusting the conductivity.

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

    Furthermore, in order to restore the processing capacity of the developer using an automatic developing machine, it is preferable to replenish by the method described in US Pat. No. 4,882,246. Developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, 56-42860, and 57-7427 are also preferable.

  A more preferable development replenisher contains an oxycarboxylic acid chelating agent having an ability to form a water-soluble chelate compound with aluminum ions, an alkali metal hydroxide, a surfactant, no silicate, and a pH of 11 A development replenisher characterized by being an aqueous solution of ˜13.5. By using such a development replenisher, it has excellent developability and characteristics that do not impair the strength of the image area of the plate material, and is formed by elution of the aluminum support by the alkali of the developer. Precipitation of aluminum is effectively suppressed, and adhesion of stains mainly composed of aluminum hydroxide to the surface of the developing bath roller of the automatic processor and subsequent accumulation of aluminum hydroxide precipitates in the washing bath are reduced. It can be processed stably for a long time.

  The lithographic printing plate precursor thus developed is subjected to washing water, surface activity as described in JP-A Nos. 54-8002, 55-11545, 59-58431, and the like. It is post-treated with a desensitizing solution containing a rinse solution containing an agent and the like, gum arabic and starch derivatives. These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention.

In the plate making of the lithographic printing plate precursor according to the present invention, for the purpose of improving the image strength and printing durability, the image after development can be subjected to entire post-heating or entire exposure.
Very strong conditions can be used for heating after development. Usually, the heating temperature is 200 to 500 ° C. If the heating temperature after development is low, sufficient image reinforcing action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

  The planographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.

  In addition, as a plate cleaner that can be used for removing stains on the plate during printing, a conventionally known plate cleaner for PS plate is used. For example, a multi cleaner, CL-1, CL-2, CP, CN-4, CN, CG-1, PC-1, SR, IC (made by Fuji Photo Film Co., Ltd.), etc. are mentioned.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. In Examples of the present application, the polymerizable composition of the present invention is applied to the recording layer of the lithographic printing plate precursor, the lithographic printing plate precursor is evaluated, and the evaluation result is evaluated for the polymerizable composition of the present invention. As a result.

[Examples 1 to 4, Comparative Examples 1 to 6]
(Production of support)
The surface treatment shown below was performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched with an aqueous solution having a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate by 5 g / m ² . Thereafter, it was washed with water.

(B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the current peak value, and the amount of electricity was 250 C / cm 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, it was washed with water.

(D) The aluminum plate was etched by spraying with an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% at 35 ° C., the aluminum plate was dissolved by 0.2 g / m ^2, and the previous stage AC was used. In addition, the smut component mainly composed of aluminum hydroxide generated during electrochemical surface roughening was removed, and the edge portion of the generated pit was dissolved to smooth the edge portion. Thereafter, it was washed with water.

(E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(F) Anodization was performed for 50 seconds at a temperature of 33 ° C. and a current density of 5 (A / dm ² ) in an aqueous solution having a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .
The surface roughness Ra of the aluminum support thus obtained was 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 micrometer) .

<Back coat layer>
Next, the following undercoat layer coating solution was applied to the back surface of the aluminum support with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 0.5 g / m ² .

-Coating liquid for back coat layer-
・ PR5542 (Sumitomo Bakelite Co., Ltd. 0.44g
(Phenol / m-cresol / p-cresol = 5/3/2 average molecular weight 5300). Fluorosurfactant 0.002 g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methanol 3.70 g
・ 0.92 g of 1-methoxy-2-propanol

<Undercoat layer>
Next, the following undercoat layer coating solution was applied to the surface of the aluminum support with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 10 mg / m ² .

-Undercoat layer coating solution-
-Polymer compound A having the following structure (weight average molecular weight: 10,000) 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

(Formation of photosensitive layer)
On this, a high-sensitivity photopolymerizable composition having the following composition was applied so that the dry coating mass was 1.4 g / m ² and dried at 125 ° C. for 34 seconds to form a photosensitive layer (recording layer).

-Photopolymerizable composition-
・ Infrared absorber (IR-1) 0.038 g
-Polymerization initiator A (S-1) 0.061g
-Polymerization initiator B (compound described in Table 1) 0.094 g
-Mercapto compound (compound described in Table 1) 0.015 g
Polymerizable compound (M-1) (A-BPE-4 manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.425 g
-Binder polymer A (B-1) 0.311g
・ Binder polymer B (B-2) 0.250 g
-Binder polymer C (B-3) 0.062g
・ Additive (A-1) 0.079g
-Polymerization inhibitor (Q-1) 0.0012g
・ Ethyl violet (EV-1) 0.021g
・ Fluorine surfactant 0.0081g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886g
・ Methanol 2.733g
・ 1-methoxy-2-propanol 5.886 g

The details of the infrared absorber, polymerization initiator, specific mercapto compound, polymerizable compound, binder polymer, additive, and ethyl violet used in Examples 1 to 4 and Comparative Examples 1 to 6 are as follows.
In addition, (I-1) used as a polymerization initiator (B) is a specific iodonium salt according to the present invention. Moreover, (E-1)-(E-5) used as a mercapto compound is a specific mercapto compound according to the present invention.

<Lower protective layer>
On the surface of the recording layer, synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300, sulfonic acid Modified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Surfactant A (Nihon Emulsion Co., Emalex 710) and Surfactant B (Adeka Pluronic P-84: Asahi Denka Kogyo Co., Ltd.) mixed aqueous solution (protective layer) Coating solution) was applied with a wire bar, and dried at 125 ° C. for 30 seconds with a hot air dryer.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in the mixed aqueous solution (coating liquid for protective layer) was 7.5 / 89/2 / 1.5 (mass). The coating amount (the coating amount after drying) was 0.5 g / m ² .

<Upper protective layer>
On the surface of the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol ( L-3266: Saponification degree 87 mol%, polymerization degree 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polymer A mixed aqueous solution (protective layer coating solution) of compound A (the above structure) and a surfactant (manufactured by Nippon Emulsion Co., Ltd.) is applied with a wire bar, and heated at 125 ° C. for 30 seconds with a hot air dryer. Dried.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / polymer compound A / surfactant in the mixed aqueous solution (protective layer coating solution) is 4.7 / 2.8. /67.4/18.6/2.3/4.2 (mass%), and the coating amount (the coating amount after drying) was 1.2 g / m ² .
In this way, a protective layer was formed on the surface of the protective layer as shown in Table 1 below, and lithographic printing plate precursors of Examples 1 to 4 and Comparative Examples 1 to 6 were obtained.

[Evaluation of planographic printing plate precursor]
(1) Evaluation of sensitivity After the obtained lithographic printing plate precursor was laminated without interleaving the interleaving paper, set on an Amiz setter manufactured by NEC, and automatically conveyed one by one, resolution 1200 dpi, outer drum rotation speed 160 rpm, Exposure was performed while changing the log E by 0.15 in the range of 0 to 19 W output. The exposure was performed under conditions of 25 ° C. and 50% RH. After the exposure, heat treatment and pre-water washing treatment before alkali development were not performed, and development processing was performed at a conveyance speed (line speed) of 2 m / min and a development temperature of 30 ° C. using an automatic developing machine LP-1310News manufactured by FUJIFILM Corporation. . The developer is a 1: 4 water diluted solution of DH-N manufactured by Fuji Film Co., Ltd., and the developer replenisher is a 1: 1.4 water diluted solution of “FCT-421” manufactured by Fuji Film Co., Ltd., finisher. Used was a 1: 1 water dilution of “GN-2K” manufactured by FUJIFILM Corporation.

  The cyan density of the image area density of the lithographic printing plate obtained by development was measured using a Macbeth reflection densitometer RD-918 and using a red filter equipped in the densitometer. The reciprocal of the exposure necessary to obtain a measured density of 0.9 was used as an index of sensitivity. The sensitivity of the lithographic printing plate obtained in Example 1 was set to 100, and the sensitivity of other lithographic printing plates was set as a relative evaluation. The larger the value, the higher the sensitivity. The results are shown in Table 1.

(2) Evaluation of sensitivity fluctuations Sensitivity fluctuations are measured in the sensitivity evaluation after each lithographic printing plate precursor obtained as described above is packaged in an environment of 25 ° C and 65% RH and stored at 60 ° C for 48 hours. In the same manner as described above, exposure and development were performed, and the difference in sensitivity between the sensitivity before storage and the sensitivity after storage was expressed. It is evaluated that the smaller the difference in variation is, the better the stability with time is, and if the variation is within 10%, it is evaluated that the stability is satisfactory with no practical problem. The results are shown in Table 1.

(3) Evaluation of residual color After storing and elapses in the same manner as in the sensitivity fluctuation evaluation in (2), the same exposure and development as in the sensitivity evaluation are performed, and the Macbeth reflection densitometer RD-918 is used for the non-image part. Then, the cyan density was measured using a red filter equipped in the densitometer, and the change between the plate before aging and the plate after aging was observed.
The case where the concentration did not change before and after aging was evaluated as ◯, and the case where the concentration became high was evaluated as ×.

(4) Residual rate of initiator after forced aging (%)
The obtained lithographic printing plate precursor 25 cm ² was immersed in 20 ml of methanol, and the remaining amount of the obtained liquid was measured by HPLC using a Waters 2690 apparatus. The eluent was 0.1% acetic acid and 0.1% triethylamine methanol, and the column was Kanto Chemical Lighttysil RP-18, 250 * Φ 4.6 mm, 5 μm. Table 1 shows the percentage of the initiator amount after storage and aging as in the case of the sensitivity fluctuation evaluation in (2), where the initiator amount before aging is 100%.

As is clear from Table 1, the lithographic printing plate precursors of Examples 1 to 4 having the recording layer containing the polymerizable composition of the present invention are excellent in that the sensitivity fluctuation due to storage is suppressed while maintaining high sensitivity. It can be seen that the storage stability is excellent, and the occurrence of residual color in the non-image area due to the undesired progress of polymerization over time is suppressed.
On the other hand, a lithographic printing plate precursor of a comparative example using a combination of a known mercapto compound and a specific iodonium salt, a lithographic printing plate precursor of a comparative example used in combination with a specific mercapto compound and a polymerization initiator outside the scope of the present invention, Although it is possible to record with high sensitivity, it is inferior in stability over time (Comparative Examples 1, 2, 4, 6), or inferior in both sensitivity and stability over time (Comparative Examples 3 and 5). It turns out that it is a planographic printing plate precursor at a problematic level.

Claims (7)

In the molecule, an alkyl group, an alkoxy group, an amino group, a urea group, an alkoxyalkyl group, Ashirokishiamino group has three even cycloalkyl group, and an electron-donating group selected from the group consisting of allyl small without A polymerizable composition comprising a diaryliodonium salt, a compound having an ethylenically unsaturated double bond, and a mercapto compound represented by the following general formula (I).

[In General Formula (I), R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a 5-membered or 6-membered heterocycle, and A may further have a substituent. ] The mercapto compound represented by the general formula (I) is at least one selected from the group consisting of a mercapto compound represented by the following general formula (II) and a mercapto compound represented by the general formula (III). The polymerizable composition according to claim 1, wherein the polymerizable composition is present.

[In general formula (II) or general formula (III), R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and X represents a halogen group, an alkoxy group. Represents a group, an alkyl group which may have a substituent, or an aryl group which may have a substituent. ]   Furthermore, an infrared absorber and a binder polymer are contained, The polymerizable composition of Claim 1 or Claim 2 characterized by the above-mentioned.   The polymerizable composition according to any one of claims 1 to 3, wherein the electron donating group of the diaryliodonium salt is an alkoxy group. The polymerizable composition according to any one of claims 1 to 3, wherein the diaryliodonium salt has a partial structure represented by the following general formula (IV).

[In General Formula (IV), R ¹ , R ² and R ³ each independently represents an alkyl group or an aryl group. ]   A lithographic printing plate precursor comprising a recording layer containing the polymerizable composition according to any one of claims 1 to 5 on a support.   The lithographic printing plate precursor as claimed in claim 6, further comprising a protective layer on the recording layer.