JP2001264991A - Original plate of planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative type original plate of a planographic printing plate excellent in the adhesion of a photosensitive layer to the substrate in an image area, less liable to stain due to defective development in a non-image area, excellent in image reproducibility and printing durability and capable of accepting with an IR laser. SOLUTION: The original plate is obtained by successively disposing a middle layer containing a polymer having an acid group and an onium group and a photosensitive layer containing I) an IR absorbent, II) a thermo- or photopolymerization initiator, III) a compound having a polymerizable unsaturated group and IV) a binder insoluble in water and soluble an aqueous alkali solution on a base made hydrophilic by treatment. The acid group of the polymer constituting the middle layer is preferably -COOH having an acid dissociation exponent (pKa) of <=7 and the onium group preferably comprises a nitrogen atom and a phosphorus or sulfur atom belonging to the group V or VI of the Periodic Table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor that can be written with an infrared laser, and more particularly, to a lithographic printing plate having a negative recording layer which has excellent adhesion of a recording layer and is less likely to cause stains in a non-image area. Regarding the printing plate.

[0002]

2. Description of the Related Art In recent years, the development of lasers has been remarkable, and in particular, solid lasers and semiconductor lasers having a light emitting region in the near infrared to infrared region have been increasing in output and miniaturization. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like. Using an infrared laser having an emission region in the infrared region as an exposure light source, a negative type lithographic printing plate material for an infrared laser, an infrared absorber, and a polymerization initiator that generates radicals by light or heat,
A lithographic printing plate material having a photosensitive layer containing a polymerizable compound.

Usually, such a negative type image recording material employs a recording system in which a polymerization reaction is caused by using a radical generated by light or heat as an initiator, and a recording layer in an exposed portion is cured to form an image portion. We are using. Such a negative type image forming material has a lower image forming property than a positive type in which the recording layer is solubilized by the energy of infrared laser irradiation, and promotes a curing reaction by polymerization to form a strong image portion. In general, a heat treatment is performed before the development step in order to form. A printing plate having such a light- or heat-polymerized recording layer is disclosed in JP-A-8-108621.
And a technique using a photopolymerizable or thermopolymerizable composition as a photosensitive layer as described in JP-A-9-34110. Although these photosensitive layers are excellent in high-sensitivity image forming properties, they use anodized (AD) treatment or an aluminum substrate that has been subjected to AD treatment and then hydrophilized with sodium silicate. When used as a support, the photosensitive layer is adsorbed to the support and the adhesion between the two is excellent, so that there is no problem in the image area, but the non-image area is not completely removed by the developer, and the printing is not performed. Time,
There has been a problem that stains in the non-image area easily occur due to the residual film of poor development. On the other hand, when a substrate treated with sodium silicate after AD treatment is used as the support, the adhesion at the interface between the photosensitive layer and the support is low. There has been a problem that the image is damaged or the image flows and the image is not formed.

In order to solve such a problem, for example,
JP-A-10-69092 proposes a lithographic printing plate provided with an intermediate layer containing a polymer compound containing a specific structural unit such as p-vinylbenzoic acid. Having a photosensitive layer of the type
Although the printing durability was excellent, it was not sufficient from the viewpoint of preventing generation of stains. For example, both effects were exhibited only in combination with a support having excellent hydrophilicity.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide an image portion having excellent adhesion between a substrate and a photosensitive layer, and a non-image portion. Accordingly, an object of the present invention is to provide a negative type lithographic printing plate precursor which is less likely to be stained by poor development and has excellent printing durability.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that by providing a specific intermediate layer on an aluminum support, it is possible to prevent the residual color in the non-image portion and to make the photosensitive layer adhere to the support. It has been found that the improvement of the performance is achieved, and the present invention has been completed. That is, the lithographic printing plate precursor of the present invention is a lithographic printing plate precursor that is compatible with a heat mode, and has an intermediate layer containing a polymer having an acid group and an onium group on an anodized aluminum support. And I) an infrared absorber, II) a thermal polymerization initiator, III) a compound having a polymerizable unsaturated group, and IV) a photosensitive layer containing a water-insoluble and aqueous alkali-soluble binder. It is characterized by the following.

In the present invention, "corresponding to the heat mode" means that recording by heat mode exposure is possible. The definition of the heat mode exposure in the present invention will be described in detail. Hans-Joachim Tim
pe, IS & Ts NIP 15: 1999 Inte
rational Conference on D
digital printing technology
ies. P. As described in 209, a photoabsorbing substance (for example, a dye) is photoexcited in a photoreceptor material, and undergoes a chemical or physical change to form a chemical or physical change from the photoexcitation of the photoabsorbing substance forming an image. It is known that there are roughly two modes in the above processes. One is that the photo-excited light-absorbing substance deactivates due to some photochemical interaction (eg, energy transfer, electron transfer) with other reactants in the photosensitive material,
As a result, a so-called photon mode in which the activated reactant causes a chemical or physical change required for the above-described image formation, and the other is that the photoexcited light absorbing substance generates heat and deactivates, and the heat is lost. This is a so-called heat mode in which a reactant causes a chemical or physical change required for image formation by utilizing the above-mentioned method. In addition, there are special modes such as ablation in which substances are explosively scattered by the energy of light locally collected and multiphoton absorption in which one molecule absorbs many photons at a time, but these modes are omitted here. The exposure process using each of the above modes is called a font mode exposure and a heat mode exposure. The technical difference between the font mode exposure and the heat mode exposure is whether or not the energy amount of several photons to be exposed can be added to the energy amount of the target reaction. For example, consider a case where a certain reaction occurs using n photons. In the font mode exposure, photochemical interaction is used, so that the energy of one photon cannot be added and used due to the requirement of the law of conservation of quantum energy and momentum. That is, in order to cause a certain reaction, the relationship of “energy amount of one photon ≧ energy amount of reaction” is necessary. On the other hand, in heat mode exposure, heat is generated after light excitation, and light energy is converted into heat and used, so that the amount of energy can be added. Therefore, the relationship “energy amount of n photons ≧ energy amount of reaction” is sufficient. However, this energy addition is restricted by thermal diffusion. In other words, if the next photoexcitation-deactivation process occurs and heat is generated before heat escapes from the exposed portion (reaction point) of interest by thermal diffusion, the heat is reliably accumulated and added, and the temperature rises in that portion. Leads to. However, when the next heat is generated slowly, the heat escapes and is not accumulated. In other words, in the heat mode exposure, even if the total exposure energy is the same, the result is different between the case where the high energy light is irradiated for a short time and the case where the low energy light is irradiated for a long time. It becomes advantageous for accumulation of.

Of course, in the font mode exposure, a similar phenomenon may occur due to the influence of the diffusion of the subsequent reactive species, but basically, this does not occur. That is, in terms of the characteristics of the photosensitive material, in the font mode, the intrinsic sensitivity of the photosensitive material (energy for reaction required for image formation) versus exposure power density (w / cm ² ) (= energy density per unit time). Amount) is constant, but in the heat mode, the intrinsic sensitivity of the photosensitive material increases with respect to the exposure power density. Therefore, when the exposure time is fixed so that the productivity necessary for practical use as an image recording material can be maintained, a high sensitivity of about 0.1 mJ / cm ² is usually obtained in the font mode exposure when comparing the modes. Reaction can be achieved at any low exposure, although
The problem of low-exposure fog is likely to occur in the unexposed area. On the other hand, in the heat mode exposure, a reaction does not occur unless the exposure amount exceeds a certain value, and usually about 50 mJ / cm ² is required in relation to the thermal stability of the photosensitive material. Is avoided. In fact, in heat mode exposure, the exposure power density on the plate surface of the photosensitive material is 500
0 w / cm ² or more, preferably 10,000
w / cm ² or more is required. However, although not described in detail here, when a high power density laser of 5.0 × 10 ⁵ / cm ² or more is used, ablation occurs, which is not preferable because of problems such as soiling the light source.

Although the function of the present invention is not clear,
By providing an intermediate layer containing a polymer having an onium salt, the polymer forming the intermediate layer has a hydrophilic onium group in the non-image area, so that the permeability to an alkali developing solution is improved, and the remaining film is removed. It becomes difficult to do. On the other hand, in the image area, the acid groups contained in the intermediate layer interact with the aluminum oxide on the anodized aluminum substrate, and the onium groups interact with the alkali-soluble groups in the photosensitive layer to improve adhesion. It is considered that the printing durability is improved by the fact that the upper layer is rapidly cured due to the polymerization system, the penetration of the developer is slowed down, and the interaction in the image area is easily maintained. In addition, when an aluminum substrate that has been hydrophilized with sodium silicate after the AD treatment is used, the polymer forming the intermediate layer has an acid group in the non-image area, and thus has a permeability to an alkali developing solution. And the remaining film is hardly formed. In the image area, between the aluminum substrate treated with sodium silicate and the photosensitive layer, the onium salt reacts with alkali-soluble groups in the photosensitive layer and SiOH groups on the substrate, such as hydrogen bonding and electrostatic interaction. It shows interaction and significantly improves the adhesion between the two, as compared with the case where the photosensitive layer is directly provided on the support. It is expected to be achieved. Further, since the heat mode is used, the exposed portion generates heat due to the exposure, and the interaction between the acid group and the aluminum oxide and the interaction between the onium salt and the SiOH group are enhanced by the heat. Furthermore, the photosensitive layer according to the present invention is made of a thermopolymerizable composition, and curing is started from an exposed portion of a surface layer by exposure to an infrared laser,
It is considered that the fact that the penetration of the developer from the surface is effectively suppressed and the developing action in the vicinity of the aluminum support is suppressed is also useful for the adhesion of the image area. In the present invention, a suitable support can be selected depending on the composition of the photosensitive layer, the type of the developer, and the like.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The photosensitive layer of the lithographic printing plate precursor according to the invention comprises I) an infrared absorber, II) a thermal polymerization initiator, III) a compound having a polymerizable unsaturated group, and IV) a water-insoluble and aqueous alkali-soluble binder. Irradiation of the infrared laser causes the I) infrared absorber to generate heat, and the light of the infrared laser or I) heat generated by the infrared absorber reacts with the II) thermal polymerization initiator to generate radicals. III) Accelerate the curing reaction of the compound having a polymerizable unsaturated group.

(Intermediate layer) The lithographic printing plate precursor of the present invention is described below.
Detailed explanation of the polymer contained in the intermediate layer of the plate
I will tell. The polymer contained in the intermediate layer according to the present invention,
A polymer having an acid group and an onium group, at least an acid
Group-containing monomer and an onium group-containing monomer
It is a compound obtained by polymerization. Here, as an acid group
Is preferably an acid group having an acid dissociation index (pKa) of 7 or less,
More preferably -COOH, -SO_ThreeH, -OSO
_ThreeH, -PO_ThreeH_Two, -OPO_ThreeH_Two, -CONHSO
_Two, -SO_TwoNHSO_TwoAnd particularly preferably -C
OOH. Also preferred as onium groups
Is an atom consisting of an atom of Group V or Group IV of the periodic table
Group, more preferably a nitrogen atom or a phosphorus atom.
Or an onium group consisting of a sulfur atom,
Or an onium group consisting of a nitrogen atom.

Among the polymers according to the present invention, compounds whose main chain structure is a vinyl polymer such as an acrylic resin, a methacrylic resin or polystyrene, a urethane resin, a polyester or a polyamide are preferred. More preferably, the main chain structure of this polymer is a vinyl polymer such as an acrylic resin, a methacrylic resin, or polystyrene, and particularly preferably, the monomer having an acid group is represented by the following general formula (1) or (2 Wherein the monomer having an onium group is a compound represented by the following general formula (3), (4) or (5): is there.

[0013]

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In the formula, A represents a divalent linking group. B is aromatic
Represents an aromatic group or a substituted aromatic group. D and E are respectively
Independently represents a divalent linking group. G represents a trivalent linking group
You. X and X 'are each independently an acid having a pKa of 7 or less.
Group or its alkali metal salt or ammonium salt
Represents R₁Is a hydrogen atom, alkyl group or halogen atom
Represents a child. a, b, d, and e are each independently 0 or
Represents 1. t is an integer of 1 to 3. Mono with acid group
More preferably, A is -COO- or -C
Represents ONH-, and B represents a phenylene group or a substituted phenyl group.
Represents a ren group, the substituents of which are a hydroxyl group and a halogen atom
Or an alkyl group. D and E are each independently
When the alkylene group or molecular formula is C_nH_2nO, C_nH_2nS
Or C_nH_{2n + 1}Represents a divalent linking group represented by N. G
Has the molecular formula C_nH_2n-1, C_nH_2n-1O, C_nH _2n-1S
Or C_nH_2nRepresents a trivalent linking group represented by N. However
Here, n represents an integer of 1 to 12. X and X '
Each independently carboxylic acid, sulfonic acid, phosphone
Shows acid, sulfuric acid monoester or phosphoric acid monoester.
You. R₁Represents a hydrogen atom or an alkyl group. a, b,
d and e each independently represent 0 or 1, but a and b
Are not simultaneously 0.

Among the monomers having an acid group, a compound represented by the general formula (1) is particularly preferred, wherein B represents a phenylene group or a substituted phenylene group, and the substituent is a hydroxyl group or an alkyl group having 1 to 3 carbon atoms. Group. D and E
Each independently represents an alkylene group having 1 to 2 carbon atoms or an alkylene group having 1 to 2 carbon atoms linked by an oxygen atom. R ₁ represents a hydrogen atom or an alkyl group. X represents a carboxylic acid group. a is 0 and b is 1.

Specific examples of the monomer having an acid group are shown below. However, the present invention is not limited to this specific example. (Specific examples of monomers having an acid group) acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride

[0017]

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[0018]

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[0019]

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Next, the polymers represented by the following general formulas (3), (4) and (5), which are monomers having an onium group, will be described.

[0021]

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In the formula, J represents a divalent linking group. K is aromatic
Represents an aromatic group or a substituted aromatic group. M are independent
Represents a divalent linking group. Y₁Represents an atom of group V in the periodic table
Represents, Y_TwoRepresents an atom belonging to Group VI of the periodic table. Z^-Is a
Represents a nonion. R_TwoIs a hydrogen atom, an alkyl group or a halo
Represents a gen atom. R_Three, R_Four, R_Five, R₇Is German
A hydrogen atom or, in some cases, a substituent
May represent an alkyl group, an aromatic group, an aralkyl group,
R₆Represents an alkylidyne group or substituted alkylidyne
Is R_ThreeAnd R_FourOr R₆And R₇Are combined
A ring may be formed. j, k, and m are each independently 0
Or represents 1. u represents an integer of 1 to 3. Onium group
More preferably, J is -COO among the monomers having
-Or -CONH-, wherein K is a phenylene group or
Represents a substituted phenylene group, and the substituent is a hydroxyl group, a halo
Gen atom or alkyl group. M is an alkylene group
Or -C_nH_2nO-, -C_nH_2nS- or -C
_nH_{2n + 1}It represents a divalent linking group represented by N-. However, this
Here, n represents an integer of 1 to 12. Y₁Is a nitrogen atom or
Represents a phosphorus atom;_TwoRepresents a sulfur atom. Z-ha
Rogen ion, PF₆ ^- , BF_Four ^-Or R₈SO_Three
^-Represents R_TwoRepresents a hydrogen atom or an alkyl group. R
_Three, R_Four, R_Five, R₇Are each independently a hydrogen atom
Alternatively, in some cases, the substituent may have a carbon number of 1 to 1.
10 represents an alkyl group, an aromatic group, or an aralkyl group;
₆Represents an alkylidine group having 1 to 10 carbon atoms or a substituted alkyl group;
Represents kyridine, but R_ThreeAnd R_FourOr R₆And R₇Haso
Each may combine to form a ring. j, k, m are
Each independently represents 0 or 1, but j and k are 0 at the same time.
There is no. R₈Is a group having 1 to 10 carbon atoms to which a substituent may be bonded.
Represents an alkyl group, an aromatic group, or an aralkyl group.

Particularly preferred among monomers having an onium group are
Preferably, K is a phenylene group or a substituted phenylene group
Represents a hydrogen atom or a group having 1 to 3 carbon atoms.
It is an alkyl group. M is an alkylene group having 1 to 2 carbon atoms
Or an alkylene group having 1 to 2 carbon atoms linked by an oxygen atom
Represents Z^-Is chlorine ion or R₈SO_Three ^-The table
You. R_TwoRepresents a hydrogen atom or a methyl group. j is 0
And k is 1. R ₈Is an alkyl group having 1 to 3 carbon atoms
Represents

Specific examples of the monomer having an onium group are shown below. However, the present invention is not limited to this specific example. (Specific examples of monomers having an onium group)

[0025]

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[0026]

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[0027]

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The monomers having an acid group may be used alone or in combination of two or more. The monomers having an onium group may be used alone or in combination of two or more. Further, the polymer according to the present invention may be a mixture of two or more monomers or those having different composition ratios or molecular weights. At this time, the polymer having a monomer having an acid group as a polymerization component contains 1% by mole or more, preferably 5% by mole of a monomer having an acid group.
It is desirable that the polymer containing a monomer having an onium group as a polymerization component contains 1% by mole or more, preferably 5% by mole or more of a monomer having an onium group.

Further, these polymers are represented by the following (1) to
At least one selected from the polymerizable monomers shown in (14) may be contained as a copolymer component. (1) N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o-, m- or p-hydroxystyrene, o- or m-bromo-p-hydroxystyrene, o- or Acrylamides, methacrylamides, acrylic esters, methacrylic esters and hydroxystyrenes having an aromatic hydroxyl group such as m-chloro-p-hydroxystyrene, o-, m- or p-hydroxyphenyl acrylate or methacrylate (2) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride and its half ester, itaconic acid, itaconic anhydride and its half ester,

(3) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) Naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Phenyl)
Methacrylamides such as methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, and o-aminosulfonylphenyl acrylate and m-aminosulfonylphenyl Acrylate, p
-Aminosulfonylphenyl acrylate, 1- (3-
Unsaturated sulfonamides such as acrylates such as aminosulfonylphenylnaphthyl) acrylate;
unsaturated sulfonamides such as methacrylates such as o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3-aminosulfonylphenylnaphthyl) methacrylate;

(4) phenylsulfonylacrylamide which may have a substituent such as tosylacrylamide;
And phenylsulfonyl methacrylamide which may have a substituent such as tosyl methacrylamide. (5) Acrylic esters and methacrylic esters having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (6) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate , Amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, etc. (Substituted) acrylates,

(7) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
Amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid
(Substituted) methacrylates such as 2-chloroethyl, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate,

(8) Acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N
-Hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N
Acrylamides such as -phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N-ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide Or methacrylamide, (9) vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether;

(10) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate; (11) styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene, and (12) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone; (13) olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene; (14) N-vinyl pyrrolidone, N-vinyl carbazole; 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.

The polymer used here contains at least 1 mol%, preferably at least 5 mol%, of a monomer having an acid group, and contains at least 1 mol%, preferably, at least 5 mol% of a monomer having an onium group. It is desirable. Furthermore, when the monomer having an acid group is contained in an amount of 20 mol% or more, the dissolving and removing property during alkali development is further improved, and when the monomer containing an onium group is contained in an amount of 1 mol% or more, adhesion is achieved due to a synergistic effect with the acid group. The performance is further improved.

The components having an acid group may be used alone or in combination of two or more, and the monomers having an onium group may be used alone or in combination of two or more. Further, the polymer according to the present invention may be a mixture of two or more monomers or those having different composition ratios or molecular weights. Next, typical examples of the polymer used in the present invention are shown below. The composition ratio of the polymer structure represents a mole percentage.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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The polymer according to the present invention can be generally produced by a radical chain polymerization method (“Textbook”).
of Polymer Science "3rd ed, (1984) FW Billmeyer, A
Wiley-Interscience Publication).

The molecular weight of the polymer according to the present invention may be in a wide range, but it is preferable that the polymer has a polymerization average molecular weight (Mw) of 500 to 2,000,000 as measured by a light scattering method. More preferably, it is in the range of 1,000 to 600,000. Further, the number average molecular weight (Mn) calculated from the integrated intensity of the terminal group and the side chain functional group in NMR measurement is preferably from 300 to 500,000, more preferably from 500 to 100,000. preferable. If the molecular weight is smaller than the above range,
The adhesion to the substrate becomes weak, and the printing durability deteriorates. On the other hand, when the molecular weight is higher than the above range, the adhesive strength to the support becomes too strong, and there is a possibility that a residual film may occur due to poor development of the photosensitive layer in the non-image area. The amount of unreacted monomer contained in the polymer may be wide,
It is preferably at most 0% by weight, more preferably at most 10% by weight.

The polymer having a molecular weight within the above range can be obtained by adjusting the amount of the polymerization initiator and the chain transfer agent used together when the corresponding monomer is copolymerized. Note that a chain transfer agent refers to a substance that moves an active site of a reaction by a chain transfer reaction in a polymerization reaction, and the likelihood of occurrence of the transfer reaction is represented by a chain transfer constant Cs. The chain transfer constant Cs × 10 ⁴ (60 ° C.) of the chain transfer agent used in the present invention is preferably 0.01 or more, more preferably 0.1 or more, and 1 or more.
It is particularly preferable that the above is satisfied. As the polymerization initiator,
A peroxide, an azo compound, and a redox initiator that are commonly used in radical polymerization can be used as they are. Of these, azo compounds are particularly preferred.

Specific examples of the chain transfer agent include halogen compounds such as carbon tetrachloride and carbon tetrabromide; alcohols such as isopropyl alcohol and isobutyl alcohol;
Olefins such as methyl-1-butene, 2,4-diphenyl-4-methyl-1-pentene, ethanethiol, butanethiol, dodecanethiol, mercaptoethanol, mercaptopropanol, methyl mercaptopropionate, ethyl mercaptopropionate, mercapto Propionic acid, thioglycolic acid, ethyl disulfide,
Examples thereof include, but are not limited to, sulfur-containing compounds such as sec-butyl disulfide, 2-hydroxyethyl disulfide, thiosalicylic acid, thiophenol, thiocresol, benzyl mercaptan, and phenethyl mercaptan.

More preferably, ethanethiol, butanethiol, dodecanethiol, mercaptoethanol,
Mercaptopropanol, methyl mercaptopropionate, ethyl mercaptopropionate, mercaptopropionic acid, thioglycolic acid, ethyl disulfide, se
c-butyl disulfide, 2-hydroxyethyl disulfide, thiosalicylic acid, thiophenol, thiocresol, benzyl mercaptan, and phenethyl mercaptan, and particularly preferably ethanethiol, butanethiol, dodecanethiol, mercaptoethanol, mercaptopropanol, and mercaptopropionic acid Methyl,
Ethyl mercaptopropionate, mercaptopropionic acid, thioglycolic acid, ethyl disulfide, sec-
Butyl disulfide and 2-hydroxyethyl disulfide.

The amount of unreacted monomer contained in the polymer may be wide, but is preferably 20 wt% or less, and more preferably 10 wt% or less.

Next, a synthesis example of the polymer according to the present invention will be described. [Synthesis Example 1] Synthesis of polymer (No. 1) p-vinylbenzoic acid [manufactured by Hokko Chemical Industry Co., Ltd.] 50.4
g, triethyl (p-vinylbenzyl) ammonium chloride (15.2 g), mercaptoethanol (1.9 g) and methanol (153.1 g) were placed in a 2-liter three-necked flask, and heated to 60 ° C. while stirring under a nitrogen stream. To this solution, 2.8 g of dimethyl 2,2'-azobis (isobutyrate) was added, and stirring was continued for 30 minutes. Thereafter, 201.5 p-vinylbenzoic acid was added to the reaction solution.
g, triethyl (p-vinylbenzyl) ammonium chloride 60.9 g, mercaptoethanol 7.5 g and dimethyl 2,2'-azobis (isobutyrate) 11.1 g
Was dissolved in 612.3 g of methanol over 2 hours. After completion of the dropwise addition, the temperature was raised to 65 ° C., and stirring was continued for 10 hours under a nitrogen stream. After completion of the reaction, the reaction solution was allowed to cool to room temperature, and the yield of the reaction solution was 1132 g, and the solid concentration was 30.5 wt%. Further, the number average molecular weight (Mn) of the obtained product was determined from the ¹³ C-NMR spectrum to find that the value was 2100.

[Synthesis Example 2] Synthesis of Polymer (No. 2) Instead of triethyl (p-vinylbenzyl) ammonium chloride, an m / p (2/1) mixture of triethyl (vinylbenzyl) ammonium chloride was used. Further, the same operation as in Synthesis Example 1 was carried out except that ethyl mercaptopropionate was used instead of mercaptoethanol, to obtain a polymer having a number average molecular weight (Mn) of 4,800.

[Synthesis Example 3] Synthesis of polymer (No. 25) p-vinylbenzoic acid [Hokuko Chemical Co., Ltd.] 146.
9 g (0.99 mol), 44.2 g (0.21 mol) of vinylbenzyltrimethylammonium chloride and 446 g of 2-methoxyethanol were placed in a 1 L three-necked flask, and heated to 75 ° C. while stirring under a nitrogen stream. Next, dimethyl 2,2-azobis (isobutyrate) 2,
76 g (12 mmol) were added and stirring continued. After 2 hours, 2,76 g of dimethyl 2,2-azobis (isobutyrate)
(12 mmol) was added. After another two hours,
2.76 g of dimethyl azobis (isobutyrate) (12 mm
ol) was added. After stirring for 2 hours, the mixture was allowed to cool to room temperature. This reaction solution was poured into 12 L of ethyl acetate with stirring. The precipitated solid was collected by filtration and dried. The yield is 18
It was 9.5 g. As a result of measuring the molecular weight of the obtained solid by a light scattering method, the weight average molecular weight (Mw) was 32,000.

The other polymers according to the invention are synthesized in a similar manner.

Further, in addition to the polymer, a compound represented by the following general formula (6) can be added to the intermediate layer in the photosensitive lithographic printing plate of the present invention. General formula (6)

[0056]

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(Wherein, R ₁ represents an arylene group having 6 to 14 carbon atoms, and m and n each independently represent an integer of 1 to 3.) For the compound represented by the above general formula (6), Will be described. The carbon number of the arylene group represented by R ₁ is 6 to
14 is preferable, and 6 to 10 are more preferable. Specific examples of the arylene group represented by R ₁ include a phenylene group, a naphthyl group, an anthryl group, and a phenathril group. The arylene group represented by R ₁ has 1 to 1 carbon atoms.
10 alkyl groups, alkenyl groups having 2 to 10 carbon atoms, alkynyl groups having 2 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, carboxylic acid ester groups, alkoxy groups, phenoxy groups, sulfonic acid ester groups, phosphonic acid Ester group,
It may be substituted with a sulfonylamide group, a nitro group, a nitrile group, an amino group, a hydroxy group, a halogen atom, an ethylene oxide group, a propylene oxide group, a triethylammonium chloride group, or the like.

Specific examples of the compound represented by the general formula (6) include, for example, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, salicylic acid, 1-hydroxy-2-
Examples include naphthoic acid, 2-hydroxy-1-naphthoic acid, 2-hydroshiki 3-naphthoic acid, 2,4-dihydroxybenzoic acid, and 10-hydroxy-9-anthracene carboxylic acid. However, the present invention is not limited to the above specific examples, and the compound represented by the general formula (6)
They may be used alone or in combination of two or more.

The intermediate layer containing the polymer according to the present invention and the compound represented by the general formula (6), which is optionally added, is formed on an aluminum support which has been subjected to a hydrophilization treatment described later. It is provided by being applied by a method.

This intermediate layer can be provided by the following method. The polymer according to the present invention and the compound represented by the general formula (6) which is added to an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like or a mixed solvent thereof or a mixed solvent of these organic solvents and water are added, if necessary. A coating method in which a dissolved solution is applied on an aluminum support and dried. Alternatively, the polymer according to the present invention and an organic solvent such as methanol, ethanol, and methyl ethyl ketone, or a mixed solvent thereof, or a mixed solvent of these organic solvents and water are represented by the general formula (6) which is added as necessary. A coating method in which an aluminum support is immersed in a solution in which a compound is dissolved, and then washed with water or air and the like and dried to form an intermediate layer can be used.

In the former method, the total of the above compounds is 0.0
A solution having a concentration of 05 to 10% by weight can be applied in various ways. For example, any method such as bar coater coating, spin coating, spray coating, and curtain coating may be used. In the latter method, the concentration of the solution is 0.005 to 20% by weight, preferably 0.01% to 10% by weight, and the immersion temperature is 0 ° C to 70 ° C, preferably 5 to 60 ° C. The time is 0.1 seconds to 5 minutes, preferably 0.5 seconds to 120 seconds.

The above solution may be a basic substance such as ammonia, triethylamine or potassium hydroxide, an inorganic acid such as hydrochloric acid, phosphoric acid, sulfuric acid or nitric acid, an organic sulfonic acid such as nitrobenzenesulfonic acid or naphthalenesulfonic acid, or phenylphosphonic acid. The pH is adjusted with various organic acidic substances such as organic phosphonic acids such as acids, benzoic acid, coumaric acid, and organic carboxylic acids such as malic acid, and organic chlorides such as naphthalene sulfonyl chloride and benzenesulfonyl chloride. More preferably, pH = 0 to 6
Can also be used. Further, in order to improve the tone reproducibility of the photosensitive lithographic printing plate, a substance absorbing ultraviolet light, visible light, infrared light or the like can be added.

After drying the compound constituting the intermediate layer of the present invention
Coating amount is 1 to 100 mg / m ^TwoIs appropriate and good
Preferably 2 to 70 mg / m^TwoIt is. The above coating amount is 1mg / m^Two
If it is less than this, a sufficient effect cannot be obtained. Also 100mg
/ m^TwoThe same applies to more than that.

(Photosensitive Layer) Next, the photosensitive layer having an image forming function in the lithographic printing plate precursor according to the invention will be described. The composition constituting the photosensitive layer includes: I) an infrared absorber;
A heat (photo) polymerizable composition containing I) a heat or photopolymerization initiator, III) a compound having a polymerizable unsaturated group, and IV) a water-insoluble and aqueous alkali-soluble binder. Examples of the thermopolymerizable composition that can be used in the present invention include, for example, JP-A-8-108621 and JP-A-9-3.
No. 4,110, JP-A-7-306528, and compositions constituting a photosensitive and heat-sensitive image recording layer.

I) Infrared absorber The infrared absorber contained in the photosensitive layer is a substance having a photothermal conversion function of generating heat by irradiation with an infrared laser.
The infrared absorbent used in the present invention has a wavelength of 760.
It is preferable that the dye or the pigment has an absorption maximum in the range from nm to 1200 nm.

As the dye, commercially available dyes and known dyes described in literatures such as “Dye Handbook” (edited by The Society of Synthetic Organic Chemistry, Japan, 1970) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes Is mentioned.

Preferred dyes include, for example, those described in
Cyanine dyes described in JP-A-8-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, etc .;
No. 96, JP-A-58-181690, JP-A-58-1
No. 94595, etc., methine dyes described in
8-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996,
Naphthoquinone dyes described in JP-A-60-52940 and JP-A-60-63744;
Squarylium dyes described in No. 12792, etc.,
Cyanine dyes described in British Patent 434,875 and the like can be mentioned.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also preferable. Pyrylium salt, JP-A-57-142645
No. (U.S. Pat. No. 4,327,169) described in JP-A-58-181051, JP-A-58-220143, JP-A-59-41363, and JP-A-59-41363.
Nos. -84248, 59-84249, 59-14
Nos. 6063 and 59-146061, pyranyl compounds, cyanine dyes described in JP-A-59-216146, pentamethinethiopyrylium salts described in U.S. Pat. No. 4,283,475, and the like. Fairness 5-13
Pyrylium compounds disclosed in JP-A-514 and JP-A-5-19702 are also preferably used.

As another preferred example of the dye, US Pat. No. 4,756,993 discloses a compound represented by the formula (I):
Near-infrared absorbing dyes described as (II) can be mentioned.

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

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In the general formula (I), X ¹ is a halogen atom,
Or an X ² -L ^1. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of a photosensitive layer coating liquid, R ¹ and R ² are preferably a hydrocarbon group having two or more carbon atoms, further, R ¹ and R ²
And particularly preferably combine with each other to form a 5- or 6-membered ring.

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 examples of the substituent include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different, and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms,
Examples include a carboxyl group and a sulfo group. R ⁵ , R ⁶ , R
⁷ and R ⁸ may be the same or different,
It represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the viewpoint of availability of raw materials, a hydrogen atom is preferable. Z ^1- represents a counter anion. However, when any of R ^{1 to} R ⁸ is substituted with a sulfo group, Z ^1- is not required. Preferred Z ¹⁻ is, from the storage stability of the photosensitive layer coating solution, a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion,
And sulfonate ions, particularly preferably perchlorate ion, hexafluorophosphate ion and arylsulfonate ion.

In the present invention, specific examples of the cyanine dye represented by the general formula (I) which can be suitably used include paragraph [0] of Japanese Patent Application No. 11-310623.
017] to [0019].

The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
Can be used.

The types of pigments include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensation azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyeing lake pigments,
Azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.
Preferred among these pigments is carbon black.

These pigments may be used without surface treatment, or may be used after surface treatment. Examples of the surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a method of bonding a reactive substance (eg, a silane coupling agent, an epoxy compound, a polyisocyanate, etc.) to the pigment surface. Can be considered. The above surface treatment methods are described in "Properties and Applications of Metallic Soap" (Koshobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).

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.
Is preferably within the range. Pigment particle size 0.01μ
If it is less than m, the dispersion is not preferred in terms of stability in the coating solution of the image-sensitive layer.

As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner 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. For details, refer to “Latest Pigment Application Technology” (CMC Publishing, 1
986).

These infrared absorbers may be added to the same layer as other components, or may be added to a separate layer provided. However, when a negative type image forming material is prepared, The optical density of the photosensitive layer at the absorption maximum in the wavelength range of 760 nm to 1200 nm is preferably between 0.1 and 3.0. Outside of this range, sensitivity tends to decrease. Since the optical density is determined by the amount of the infrared absorbing agent added and the thickness of the recording layer, a predetermined optical density can be obtained by controlling both conditions. The optical density of the recording layer can be measured by a conventional method. As a measuring method, for example, on a transparent or white support, a coating layer after drying is formed to a recording layer having a thickness appropriately determined in a range necessary for a lithographic printing plate, and a transmission type optical densitometer is used. Examples include a method of measuring, a method of forming a recording layer on a reflective support such as aluminum, and measuring a reflection density.

II) Polymerization Initiator The polymerization initiator is used in combination with the above-mentioned I) infrared absorber, and when irradiated with an infrared laser, a radical is generated by the light or heat or both energies. Initiate polymerization of a compound having an unsaturated group,
Refers to a compound that promotes. As the polymerization initiator according to the present invention, known photopolymerization initiators, thermal polymerization initiators and the like can be selected and used, for example, onium salts, triazine compounds having a trihalomethyl group, peroxides, azo compounds. Examples thereof include a system polymerization initiator, an azide compound, and a quinonediazide, and an onium salt is preferable because of its high sensitivity. The onium salt that can be suitably used as a polymerization initiator in the present invention will be described. Preferred onium salts include iodonium salts, diazonium salts, and sulfonium salts. In the present invention, these onium salts function not as acid generators but as radical polymerization initiators. Onium salts suitably used in the present invention are onium salts represented by the following general formulas (III) to (V).

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In the formula (III), Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms which may have a substituent. When the aryl group has a substituent, preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a 12 or less carbon atom. Aryloxy groups. Z ^11- represents a counter ion selected from the group consisting of a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, and is preferably a perchlorate ion or a hexafluorophosphate. And arylsulfonate ions.

In the formula (IV), Ar ²¹ represents an aryl group having 20 or less carbon atoms which may have a substituent. Preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and a 12 or less carbon atom. Alkylamino group, dialkylamino group having 12 or less carbon atoms, 1 carbon atom
An arylamino group having 2 or less or a diarylamino group having 12 or less carbon atoms is exemplified. Z ^{21 -} is Z ^11-
Represents a counter ion having the same meaning as

In the formula (V), R ³¹ , R ³² and R ³³ may be the same or different and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, and an aryloxy group having 12 or less carbon atoms. Z ^31- represents a counter ion having the same ^meaning as Z ^11- .

In the present invention, specific examples of onium salts that can be suitably used as a radical generator include:
Paragraph number [003 of Japanese Patent Application No. 11-310623]
0] to [0033].

The general formula (I) described in paragraphs [0012] to [0050] of JP-A-9-34110
-Onium salts represented by formulas (IV) to (IV):
Known polymerization initiators such as the thermal polymerization initiator described in Paragraph No. [0016] of JP-A-1 (1998) are also preferably used. The radical generator used in the present invention has a maximum absorption wavelength of 4
00 nm or less, preferably 360 nm
The following is preferred. By setting the absorption wavelength in the ultraviolet region, the image forming material can be handled under a white light.

III) Compound Having a Polymerizable Unsaturated Group The compound having a polymerizable unsaturated group used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, Preferably, it is selected from compounds having at least one, and preferably at least two, terminal ethylenically unsaturated bonds. Such compounds are widely known in the industrial field, and they can be used in the present invention without any particular limitation. These are, for example, monomers, prepolymers, ie dimers,
Includes those having chemical forms such as trimers and oligomers, or mixtures thereof, and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and esters and amides thereof, and are preferred. As the ester, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. Further, an unsaturated carboxylic acid ester having a nucleophilic substituent such as a hydroxyl group, an amino group or a mercapto group, an addition reaction product of an amide with a monofunctional or polyfunctional isocyanate, an epoxy,
A dehydration condensation product with a monofunctional or polyfunctional carboxylic acid is also preferably used.

Also, unsaturated carboxylic acid esters, amides and monofunctional or polyfunctional alcohols having an electrophilic substituent such as an isocyanato group or an epoxy group,
Amines, addition products with thiols, halogen groups,
Substitution products of unsaturated carboxylic esters and amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines and thiols are also suitable. As another example, it is also possible to use a group of compounds in which unsaturated phosphonic acid, styrene, vinyl ether or the like is substituted for the above unsaturated carboxylic acid.

Specific examples of the ester monomer of the aliphatic polyhydric alcohol compound and the unsaturated carboxylic acid include acrylates such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3.
-Butanediol diacrylate, 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, SO Bito one Le pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

Examples of the methacrylate include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, and 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-hi Rokishipuropokishi) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate,
There are 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetritaconate and the like.

The crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Sorbitol tetradicrotonate and the like. Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

The maleic acid ester includes ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, sorbitol tetramaleate and the like.

Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, and JP-A-57-196231, and JP-A-59-5240 and JP-A-59-5240. 59-524
1, those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Further, the above-mentioned ester monomers can be used as a mixture.

Specific examples of the amide monomer of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide, and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

A urethane-based addition-polymerizable compound produced by an addition reaction between an isocyanate and a hydroxyl group is also suitable.
JP-A-8-41708 discloses a polyisocyanate compound having two or more isocyanate groups per molecule, to which a hydroxyl-containing vinyl monomer represented by the following general formula (2) is added. Examples include vinyl urethane compounds containing two or more polymerizable vinyl groups.

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In the general formula (2), R and R ′ represent H or CH3. Also, urethane acrylates described in JP-A-51-37193, JP-B-2-32293 and JP-B-2-16765, and
Urethane compounds having an ethylene oxide skeleton described in JP-A-8-49860, JP-B-56-17654, JP-B-62-39417, and JP-B-62-39418 are also suitable.

Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277563, JP-A-63-260909 and JP-A-1-105238. Can obtain a photosensitive composition having a very high photosensitive speed.

As another example, see JP-A-48-641.
No. 83, JP-B-49-43191, JP-B-52-30
No. 490, polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid as described in each publication. Also,
JP-B-46-43946, JP-B-1-40337,
Specific unsaturated compounds described in JP-B-1-40336,
Vinyl phosphonic acid compounds described in JP-A-2-25493 can also be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Further, the Journal of the Adhesion Society of Japan vol. 20, no. 7, pages 300 to 308 (1
984) as photocurable monomers and oligomers.

Regarding these addition polymerizable compounds, what kind of structure is used, whether they are used alone or in combination,
Details of the method of use, such as the amount of addition, can be arbitrarily set in accordance with the final performance design of the light-sensitive material. For example, it is selected from the following viewpoints. From the viewpoint of the photosensitive speed, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or more functional structure is preferable. In order to increase the strength of the image area, that is, the cured film, those having three or more functional groups are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylates, methacrylates, styrene compounds, vinyl ethers) It is also effective to adjust both the photosensitivity and the intensity by using the compound (1) in combination. A compound having a large molecular weight or a compound having a high hydrophobicity is excellent in photosensitive speed and film strength, but may not be preferable in terms of developing speed and precipitation in a developing solution.

Further, compatibility with other components (eg, binder polymer, initiator, colorant, etc.) in the photosensitive composition,
The selection and use of the addition polymerization compound is also an important factor for the dispersibility. For example, the use of a low-purity compound or the combination of two or more compounds may improve the compatibility. In the case of a lithographic printing plate precursor, a specific structure may be selected for the purpose of improving the adhesion of a support, an overcoat layer, and the like described below. Regarding the compounding ratio of the addition polymerizable compound in the photosensitive composition, the larger the proportion, the more advantageous in sensitivity. Process problems (for example, improper production due to transfer of photosensitive material components or adhesion)
In the case of a lithographic printing plate precursor, problems such as precipitation from a developing solution may occur. From these viewpoints, the preferred compounding ratio is often 5 to 8 based on all components of the composition.
0% by weight, preferably 25 to 75% by weight. Also,
These may be used alone or in combination of two or more. In addition, the method of using the addition polymerizable compound can be arbitrarily selected from the viewpoints of the degree of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, etc. Depending on the case, a layer structure and a coating method such as undercoating and overcoating may be performed.

IV) Binder Insoluble in Water and Soluble in Alkaline Aqueous Solution In the lithographic printing plate precursor according to the invention, it is preferable to further use a binder polymer in the photosensitive layer. It is preferable to contain a linear organic high molecular polymer as the binder. Any of such “linear organic high molecular polymers” may be used. Preferably, a water- or weakly alkaline water-soluble or swellable linear organic high molecular polymer that enables water development or weakly alkaline water development is selected. The linear organic high molecular polymer is selected and used not only as a film forming agent of the composition but also as a water, weakly alkaline water or organic solvent developing agent. For example, when a water-soluble organic high molecular polymer is used, water development becomes possible. Examples of such a linear organic high molecular polymer include an addition polymer having a carboxylic acid group in a side chain, for example, Japanese Unexamined Patent Publication No.
Nos. 9-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-54-92723, JP-A-59-53836, and JP-A-59-71048. Those described, that is, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, partially esterified maleic acid copolymer, and the like. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful.

In particular, among these, [benzyl (meth) acrylate / (meth) acrylic acid / if necessary, other addition-polymerizable vinyl monomers] copolymer and [allyl (meth) acrylate / (meth) acrylic acid / Other addition-polymerizable vinyl monomers as needed) copolymer,
It is suitable because it has an excellent balance of film strength, sensitivity and developability.

Further, Japanese Patent Publication No. 7-12004, Japanese Patent Publication No.
JP-A-120041, JP-B-7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A-1-271174,
The urethane-based binder polymer containing an acid group described in Japanese Patent Application No. 10-116232 is very excellent in strength, and therefore is advantageous in terms of printing durability and low exposure suitability.
Further, a binder having an amide group described in JP-A-11-171907 is suitable because it has excellent developability and film strength.

Further, as the water-soluble linear organic polymer, polyvinyl pyrrolidone, polyethylene oxide and the like are useful. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful. These linear organic high molecular polymers can be incorporated in any amount in the entire composition. However, if it exceeds 90% by weight, no favorable result is obtained in view of the strength of the formed image and the like. Preferably 30 to 85
% By weight. The weight ratio of the photopolymerizable compound having an ethylenically unsaturated double bond and the linear organic high molecular polymer is preferably in the range of 1/9 to 7/3.

The binder polymer of the present invention is substantially insoluble in water and soluble in an aqueous alkali solution. For this reason, an organic solvent which is not environmentally unfavorable is not used or the amount used is extremely small as a developer.
The acid value (the acid content per gram of the polymer expressed by a chemical equivalent number) and the molecular weight of such a binder polymer are appropriately selected from the viewpoint of image strength and developability. Preferred acid values are 0.4-3. The molecular weight is Omeq / g, and the preferred molecular weight is in the range of 3,000 to 500,000, and more preferably the acid value is in the range of 0.6 to 2.0, and the molecular weight is in the range of 10,000 to 300,000.

(V) Other Components The photosensitive composition of the present invention may further contain other components suitable for its use, production method and the like.
Hereinafter, preferred additives will be exemplified. (V-1) Co-sensitizer The sensitivity can be further improved by using a certain additive (hereinafter referred to as a co-sensitizer). Although their mechanism of action is not clear, most are thought to be based on the following chemical processes. That is, a co-sensitizer reacts with a photoreaction initiated by a thermal polymerization initiator and various intermediate active species (radicals, cations) generated during the subsequent addition polymerization reaction to generate a new active radical. It is estimated that These are roughly (a) those that can be reduced to produce active radicals, (b) those that can be oxidized to produce active radicals, and (C) those that react with less active radicals and are more active radicals. Or acting as a chain transfer agent, but it is often unconventional as to which of these compounds an individual compound belongs to.

(A) Compound which generates an active radical by being reduced Compound having a carbon-halogen bond: It is considered that a carbon-halogen bond is reductively cleaved to generate an active radical. Specifically, for example, trihalomethyl-s-
Triazines, trihalomethyloxadiazoles and the like can be suitably used. Compounds having a 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 an oxygen-oxygen bond: It is considered that an oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides and the like are preferably used. Onium compounds: carbon-hetero bond or oxygen-
It is thought that the nitrogen bond is cleaved to generate an active radical. Specifically, for example, diaryliodonium salts,
Triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used. Ferrocene, iron arene complexes: can generate active radicals reductively.

(B) Compound which is oxidized to generate an active radical Alkyl ate 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 CX 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-trimethylsilylmethylanilines and the like. Sulfur-containing and tin-containing compounds: The above-mentioned amines in which the nitrogen atom is replaced with a sulfur atom or a tin atom can generate an active radical by the same action. Compounds having an SS bond are also known to be sensitized by SS cleavage.

Α-Substituted methylcarbonyl compound: An active radical can be generated by the cleavage of carbonyl-α carbon bond by oxidation. In addition, those obtained by converting carbonyl to oxime ether also show the same action. In particular,
2-alkyl-1- [4- (alkylthio) phenyl]
-2-Morpholinopronones-1 and oxime ethers obtained by reacting these with hydroxyamines and then etherifying N-OH. Sulfinates: Active radicals can be generated reductively. Specific examples include sodium arylsulfin and the like.

(C) Compounds which react with radicals to convert them into highly active radicals or act as chain transfer agents: For example, compounds having SH, PH, SiH, GeH in the molecule are used. These can generate a radical by donating hydrogen to a low-activity radical species, or can generate a radical by being oxidized and then deprotonated. Specific examples include 2-mercaptobenzimidazoles.

Many more specific examples of these co-sensitizers are described in, for example, JP-A-9-236913 as additives for the purpose of improving sensitivity. Can also be applied. These co-sensitizers can be used alone or in combination of two or more. The amount is suitably in the range of 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 3 to 50 parts by weight, per 100 parts by weight of the compound having an ethylenically unsaturated double bond.

(V-2) Polymerization Inhibitor In the present invention, in addition to the above basic components, there is no need for a compound having an ethylenically unsaturated double bond which can be polymerized during the production or storage of the photosensitive composition. It is desirable to add a small amount of a thermal polymerization inhibitor to prevent the thermal polymerization. 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-t-butylphenol), cerium N-nitrosophenylhydroxyamine, and the like. The amount of the thermal polymerization inhibitor added is about 0.01 to the weight of the whole composition.
% By weight to about 5% by weight is preferred. In addition, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition by oxygen, and when used as a lithographic printing plate precursor, after application to a support or the like, During the drying process, it may be unevenly distributed on the surface of the photosensitive layer. The amount of the higher fatty acid derivative to be added ranges from about 0.5% by weight to about 10% by weight of the total composition.
% By weight is preferred.

(V-3) Colorant, etc. When the photosensitive composition of the present invention is used for a lithographic printing plate precursor, a dye or pigment may be added for the purpose of coloring the photosensitive layer. As a result, as a printing plate,
It is possible to improve so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring device. As a coloring agent, since many dyes cause a decrease in the sensitivity of the photopolymerizable photosensitive layer,
As the colorant, use of a pigment is particularly preferable. 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. Dyes and pigments may be added in an amount of about 0.5% to about 5% by weight of the total composition.
% By weight is preferred.

(V-4) Other Additives When the photosensitive composition of the present invention is used for a lithographic printing plate precursor, an inorganic filler, other plasticizers, and a photosensitive agent are used to improve the physical properties of the cured film. A known additive such as a sensitizer that can improve the ink inking property of the layer surface may be added.

Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin and the like. A binder was used. In this case, it can be added in an amount of 10% by weight or less based on the total weight of the compound having an ethylenically unsaturated double bond and the binder.

Further, a UV initiator, a mature crosslinking agent, etc. can be added to enhance the effect of heating and exposure after development for the purpose of improving the film strength (printing durability) described later. In addition, it is possible to provide an additive and an intermediate layer for improving the adhesion between the photosensitive layer and the support and for improving the development and removability of the unexposed photosensitive layer. For example, a compound having a diazonium structure or a phosphone compound, such as a compound having a relatively strong interaction with the substrate or an undercoat, the adhesion is improved,
The printing durability can be increased, while the addition or undercoating of a hydrophilic polymer such as polyacrylic acid or polysulfonic acid improves the developability of the non-image area and improves the stain resistance.

When the photosensitive composition of the present invention is applied on a support to provide a lithographic printing plate, it is used after being dissolved in various organic solvents. As the solvent used here, 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, Ethylene 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, etc. These solvents can be used alone or as a mixture. The concentration of the solid content in the coating solution is 2
~ 50% by weight is suitable.

The amount of the photosensitive layer to be applied to the support is desirably appropriately selected depending on the application in consideration of the effects of the sensitivity and developability of the photosensitive layer and the strength and printing durability of the exposed film. When the coating amount is too small, the printing durability becomes insufficient. On the other hand, if the amount is too large, the sensitivity is lowered, and it takes a long time for exposure, and a longer time is required for the developing process, which is not preferable. The coating amount of the lithographic printing plate precursor according to the invention is generally about 0. lg / m ² to about 10 g / m ²
Is appropriate. More preferably 0.5 to 5 g / m
²

"Protective Layer" The lithographic printing plate precursor according to the invention is usually provided with a protective layer on the photopolymerizable composition layer, since exposure is usually performed in the air. The protective layer is
The present invention prevents low-molecular compounds such as oxygen and basic substances present in the atmosphere that inhibit an image forming reaction caused by exposure in the photosensitive layer from being mixed into the photosensitive layer, thereby enabling exposure in the atmosphere.
Therefore, the desired properties of such a protective layer is that the permeability of low molecular compounds such as oxygen is low, and further, the transparency of light used for exposure is good, and the adhesion with the photosensitive layer is excellent.
In addition, it is desirable that it can be easily removed in a developing step after exposure.

Such a device for the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used, and specifically, polyvinyl alcohol, polyvinylpyrrolidone, acidic celluloses, gelatin, gum arabic, and polystyrene. Although water-soluble polymers such as acrylic acid are known, use of polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, or an acetal as long as it contains an unsubstituted vinyl alcohol unit for obtaining necessary oxygen barrier properties and water solubility. Similarly, a part thereof may have another copolymer component.

Specific examples of polyvinyl alcohol include 7
1-100% hydrolyzed, molecular weight 300-240
A range of 0 can be given. Specifically, Kuraray's PVA-105, PVA-110, PVA
A-117, PVA-117H, PVA-120, PV
A-124, PVA-124H, PVA-CS, PVA
-CST, PVA-HC, PVA-203, PVA-2
04, PVA-205, PVA-210, PVA-21
7, PVA-220, PVA-224, PVA-217
EE, PVA-217E, PVA-220E, PVA-
224E, PVA-405, PVA-420, PVA-
613 and L-8.

The components of the protective layer (selection of PVA, use of additives), coating amount, etc. are selected in consideration of fogging properties, adhesion and scratch resistance in addition to oxygen barrier properties and development removal properties. Generally, the higher the hydrolysis rate of the PVA used (the higher the content of unsubstituted vinyl alcohol units in the protective layer) and the thicker the film thickness, the higher the oxygen barrier properties, which is advantageous in terms of sensitivity. However, when the oxygen barrier property is extremely increased, there arises a problem that an unnecessary polymerization reaction occurs at the time of production or raw storage, and that unnecessary fogging and thickening of an image occur at the time of image exposure. Further, the adhesion to the image area and the scratch resistance are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on a lipophilic polymer layer, film peeling due to insufficient adhesive force tends to occur, and the peeled portion causes defects such as poor film curing due to inhibition of oxygen polymerization.

On the other hand, various proposals have been made to improve the adhesiveness between these two layers. For example, US Patent No. 2
No. 92,501 and U.S. Pat. No. 44,563, an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer or the like is mixed in a hydrophilic polymer mainly composed of polyvinyl alcohol in an amount of 20 to 60% by weight. It is described that sufficient adhesiveness can be obtained by laminating on a polymer layer. Any of these known techniques can be applied to the protective layer in the present invention. Regarding the method of applying such a protective layer,
For example, U.S. Pat. No. 3,458,311;
No. 49729.

Further, other functions can be imparted to the protective layer. For example, it excels in the transmission of light of the wavelength used for exposure,
And can efficiently absorb light of a wavelength not related to exposure,
By adding a coloring agent (such as a water-soluble dye), the suitability for safelight can be further increased without lowering the sensitivity.

(Support) The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, plastic (for example,
Paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate) laminated with polyethylene, polypropylene, polystyrene, etc. Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.). These are single component sheets such as resin films and metal plates,
The laminate may be a laminate of two or more materials, for example, such as the above-described metal-laminated or vapor-deposited paper or plastic film, or a laminated sheet of different types of plastic films.

As the support, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of foreign elements in the alloy is at most 10% by weight
It is as follows. Particularly preferred aluminum in the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the aluminum plate,
About 0.1 to 0.6 mm, preferably 0.15 to
It is 0.4 mm, particularly preferably 0.2 to 0.3 mm.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent, or an aqueous alkaline solution for removing rolling oil on the surface is performed. The surface roughening treatment of the aluminum plate is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. In addition, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte. Also,
As disclosed in JP-A-54-63902, a method in which both are combined can also be used. The aluminum plate thus roughened can be subjected to an anodic oxidation treatment through alkali etching treatment and neutralization treatment, if desired, in order to increase the water retention and abrasion resistance of the surface. As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.

The anodizing treatment conditions vary depending on the electrolyte to be used and cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70.degree.
Current density 5 to 60 A / dm ^2, voltage 1 to 100 V, which is an electrolyzing time of 10 seconds to 5 minutes. The amount of the anodized film is suitably 1.0 g / m ² or more, but more preferably in the range of 2.0 to 6.0 g / m ^2. When the anodic oxide coating is less than 1.0 g / m ² , the printing durability is insufficient, and the non-image area of the lithographic printing plate is easily damaged, and the ink adheres to the damaged area during printing. "Scratch dirt" is likely to occur. Although such anodizing treatment is performed on a surface used for printing of the support of lithographic printing plates, the back around the electric lines of force, 0.01 to 3 g / m ² on the back surface
Is generally formed.

The hydrophilic treatment of the support surface is performed after the above-described anodic oxidation treatment, and a conventionally known treatment method is used. As such a hydrophilic treatment,
U.S. Pat. Nos. 2,714,066 and 3,181,4
No. 61, No. 3,280,734 and No. 3,902,7
There is an alkali metal silicate (for example, an aqueous solution of sodium silicate) disclosed in Japanese Patent No. 34-34. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolytically treated. In addition, Japanese Patent Publication No. 36-22
No. 063, and potassium fluoride zirconate disclosed in U.S. Pat. Nos. 3,276,868 and 4,15.
For example, a method of treating with polyvinyl phosphonic acid as disclosed in JP-A-3,461 and JP-A-4,689,272 is used. Among these, a particularly preferred hydrophilic treatment in the present invention is a silicate treatment. The silicate treatment will be described below.

The anodic oxide film of the aluminum plate treated as described above was coated with an alkali metal silicate in an amount of 0.1 to 30% by weight, preferably 0.5 to 10% by weight, and a pH at 25 ° C. of 10 to 10% by weight. Aqueous solution, for example, 15 to 80
Soak at 0.5C for 0.5-120 seconds. If the pH of the alkali metal silicate aqueous solution is lower than 10, the solution will gel, and if it is higher than 13.0, the oxide film will be dissolved. As the alkali metal silicate used in the present invention, sodium silicate, potassium silicate, lithium silicate and the like are used. Hydroxides used to increase the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide and lithium hydroxide. In addition, an alkaline earth metal salt or a Group IVB metal salt may be added to the above-mentioned processing solution.
Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate and barium nitrate, and water-soluble salts such as sulfates, hydrochlorides, phosphates, acetates, oxalates and borates. No. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride and the like. Can be. Alkaline earth metal salt or
The Group IVB metal salts can be used alone or in combination of two or more. The preferred range of these metal salts is 0.0
1 to 10% by weight, more preferably 0.05 to 10% by weight.
5.0% by weight. Since the silicate treatment further improves the hydrophilicity on the aluminum plate surface, the ink hardly adheres to the non-image area during printing, and the stain performance is improved.

On the back surface of the support, a back coat is provided if necessary. Examples of the back coat include a coating comprising a metal oxide obtained by hydrolyzing and polycondensing an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. Layers are preferably used. Among these coating layers, Si (OCH ₃ ) ₄ , Si (OC
_{2 H 5) 4, Si (} OC 3 H 7) 4, Si (OC
Alkoxy compounds of silicon such as ₄ H ₉ ) ₄ are inexpensive and readily available, and a coating layer of a metal oxide provided therefrom is particularly preferred because of its excellent development resistance.

(Exposure) As described above, the planographic printing plate precursor of the invention can be prepared. This lithographic printing plate precursor is image-exposed by a solid-state laser and a semiconductor laser that emit infrared light having a wavelength of 760 nm to 1200 nm. In the present invention, the developing treatment may be performed immediately after the laser irradiation, or the heat treatment may be performed between the laser irradiation step and the developing step. The conditions of the heat treatment are 80 ° C to 15 ° C.
It is preferable to carry out for 10 seconds to 5 minutes within the range of 0 ° C. By this heat treatment, the laser energy required for recording at the time of laser irradiation can be reduced.

(Developer) When a photosensitive material using the photosensitive composition of the present invention is used as an image forming material, it is usually
After image exposure, an unexposed portion of the photosensitive layer is removed with a developer to obtain an image. Preferred developers when these photopolymerizable compositions are used for preparing a lithographic printing plate include those described in JP-B-57-7427, such as sodium silicate and potassium silicate. Like sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, etc. An aqueous solution of a suitable inorganic alkali agent or an organic alkali agent such as monoethanolamine or diethanolamine is suitable. The alkaline solution is added so that the concentration of the alkaline solution is 0.1 to 10% by weight, preferably 0.5 to 5% by weight.

Also, such an alkaline aqueous solution includes:
If necessary, a small amount of a surfactant or an organic solvent such as benzyl alcohol, 2-phenoxyethanol or 2-butoxyethanol can be contained. For example, those described in U.S. Pat. Nos. 3,375,171 and 3,615,480 can be mentioned. Further, Japanese Unexamined Patent Publication No.
Nos. 0-26601, 58-54341, Tokubo Sho56
The developers described in JP-A-39464 and JP-A-56-42860 are also excellent.

The lithographic printing plate obtained as described above can be subjected to a printing step after coating with a desensitizing gum if desired. Is subjected to a burning process. When burning a lithographic printing plate, before burning,
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-regulating liquid as described in JP-A Nos. 1859 and 61-159655. As the method, a method of applying the printing solution on a lithographic printing plate with a sponge or absorbent cotton impregnated with the surface conditioning solution, or immersing the printing plate in a vat filled with the surface conditioning solution, Application by an automatic coater or the like is applied. Further, it is more preferable to make the amount of the coating uniform with a squeegee or a squeegee roller after the coating.

The lithographic printing plate that has been subjected to the burning treatment can be subjected to a conventional treatment such as washing with water or gumming if necessary. When a liquid is used, a so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such a process is set on an offset printing machine or the like and used for printing a large number of sheets.

[0140]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Examples 1 to 5, Comparative Examples 1 to 3) [Preparation of Substrate] An aluminum plate (material 1050) having a thickness of 0.3 mm was washed and degreased with trichlorethylene, and then a nylon brush and a 400 mesh pumice were used. The surface was grained with a water suspension and washed well with water. This plate was immersed in a 25% aqueous solution of sodium hydroxide at 45 ° C. for 9 seconds to perform etching, washed with water, further immersed in 20% nitric acid for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² . Then this board is 7%
At a current density of 15A / dm ² sulfuric acid as electrolyte 3 g / m
^After the DC anodic oxide coating of No. ² was provided, the substrate was washed with water and dried to prepare a substrate [A]. Substrate [A] is sodium silicate 2
The substrate was treated with a 15% by weight aqueous solution at 25 ° C. for 15 seconds and washed with water to prepare a substrate [B].

[Formation of Intermediate Layer] A solution containing the following polymer according to the present invention (the polymer shown in Table 1) was applied onto the substrate [A] or [B] prepared as described above, and then coated. 15 at ℃
After drying for 2 seconds, an intermediate layer was provided. The coating amount after drying is 15
mg / m ² .

(Intermediate layer coating solution) Polymer shown in Table 1 0.3 g Methanol 100 g Water 1 g

[0144]

[Table 1]

The following photosensitive layer coating solution was applied onto the substrate prepared as described above so that the coating amount was 1.5 g / m ² .

(Coating solution of photosensitive layer) 1.5 g of pentaerythritol tetraacrylate 2.0 g of allyl methacrylate / methacrylic acid copolymer (83/17) 0.1 g of infrared absorbent DX-1 (the following structure) 0.1 g Polymerization Initiator SX-1 (the following structure) 0.2 g-Fluorinated nonionic surfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02 g-Victoria Pure Blue 0.04 g-Methyl ethyl ketone 10 g- 7 g of methanol 10 g of 2-methoxy-1-propanol

For comparison, a substrate having no intermediate layer was prepared on the substrate [A], and the photosensitive layer-forming coating solutions 1 and 2 were coated on the substrate so that the coating amount was 1.8 g / m ^2. Apply,
A lithographic printing plate precursor was obtained (Comparative Example 1). Further, for comparison, a substrate having no intermediate layer was prepared on the substrate [B], and a photosensitive layer coating solution was applied so that the coating amount was 1.5 g / m ² to obtain a lithographic printing plate precursor ( Comparative Example 2). Furthermore, a solution containing the polymer P-1 shown below, which is described in JP-A-10-69092, was applied onto the substrate [B], and dried at 80 ° C. for 15 seconds to form an intermediate layer. . The coating amount after drying was 20 mg / m ² . Thereafter, a photosensitive layer coating solution was applied onto the substrate so that the coating amount was 20 mg / m ² , to obtain a lithographic printing plate precursor (Comparative Example 3).

[0148]

Embedded image

(Examples 6 to 10 and Comparative Examples 4 and 5) On the same substrate [A] or [B] as in Example 1, instead of the polymer used in Example 1, the following Table 2 was used. A substrate having an intermediate layer formed thereon was obtained in the same manner as in Example 1 except that an intermediate layer was formed using the polymer described.

[0150]

[Table 2]

The following photosensitive layer coating solution 2 was applied onto the intermediate layer so that the coating amount was 1.5 g / m ² , to obtain a lithographic printing plate precursor.

(Photosensitive Layer Coating Solution 2) 50 parts by weight of binder polymer (hydroxyethyl methacrylate / methyl methacrylate / butyl acrylate / acrylic acid copolymer (30/50/5/15)) monomer: polymerizable compound (di 50 parts by weight of pentaerythritol hexaacrylate) 10 parts by weight of infrared absorber IR-5 (the following structure) 5 parts by weight of polymerization initiator A-1 (the following structure) 5 parts by weight of onium salt QN-1 (the following structure)・ 400 parts by weight of methyl ethyl ketone

[0153]

Embedded image

For comparison, a substrate having no intermediate layer was prepared on the substrate [A] and the substrate [B] prepared in Example 1, and then the photosensitive layer coating liquid 2 was coated on this substrate in a coating amount. The composition was applied to 1.5 g / m ² to obtain a lithographic printing plate precursor (Comparative Examples 4 and 5).

(Examples 11 and 12) On the same substrate [A] or [B] as in Example 1, instead of the polymer used in Example 1, a polymer shown in Table 3 below was used. A substrate having an intermediate layer formed thereon was obtained in the same manner as in Example 1 except that the intermediate layer was formed.

[0156]

[Table 3]

The following photosensitive layer coating solution 3 was applied on the intermediate layer so that the coating amount was 1.5 g / m ² , to obtain a lithographic printing plate precursor. (Photosensitive layer coating liquid 3)-Binder polymer (methyl methacrylate / methacrylic acid copolymer (80/20) Mw = 25,000) 0.75 g-Polymerizable compound (dipentaerythritol hexaacrylate, DPHA, Nippon Kayaku Co., Ltd.) )) 0.74 g ・ Infrared absorber (carbon black dispersion, carbon black content 33% by weight) 1.21 g ・ Polymerization initiator (benzoyl peroxide) 0.1 g ・ Methyl ethyl ketone 7.19 g

(Examples 13 to 15, Comparative Examples 6 and 7) On the same substrate [B] as in Example 1, instead of the polymer used in Example 1, the polymers shown in Table 4 below were used. A substrate on which an intermediate layer was formed was obtained in the same manner as in Example 1 except that an intermediate layer was formed by using the above method.

[0159]

[Table 4]

On the intermediate layer, the following photosensitive layer coating solution 4 was applied so that the coating amount was 1.5 g / m ² to obtain a lithographic printing plate precursor.

(Photosensitive Layer Coating Solution 4) Binder polymer (allyl acrylate / methacrylic acid / N-isopropylamide copolymer (67/13/20)) 2.0 g Monomer: Polymerizable compound (dipentaerythritol hexacryl) Rate) 1.0 g ・ Infrared absorber DX-1 (the above structure) 0.1 g ・ Polymerization initiator SX-2 (the following structure) 0.2 g ・ Fluorine nonionic surfactant (MegaFac F-177, Dainippon Ink) 0.02 g ・ Victoria Pure Blue 0.04 g ・ Methanol 10 g ・ Methyl ethyl ketone 15 g

[0162]

Embedded image

For comparison, the substrate [A] used in Example 1 was used.
Further, a substrate having no intermediate layer was prepared on the substrate [B], and the photosensitive layer coating solution 4 was applied so that the coating amount was 1.5 g / m ² to obtain a lithographic printing plate precursor (Comparative Example). 6, 7).

In the developing step, an alkali developing solution used for developing a plate using the substrate [B] was a developing solution DN-3L (manufactured by Fuji Photo Film Co., Ltd., diluted with water at 1: 2). ) Was used. Further, the development of the plate using the substrate [A] includes a developing solution DP-4 manufactured by Fuji Photo Film Co., Ltd.
(Water-diluted at a ratio of 1: 8) was used.

Using the obtained lithographic printing plate precursor, a Cresor plate setter Trendsetter 3244 was used.
Exposure conditions: After exposure at a rotation speed of 115 rpm and an output of 65 W, the developing solution and the rinsing solution FR-
3 (1: 7) was developed using a purple-blue automatic developing machine (PS Processor 900VR, manufactured by Fuji Photo Film Co., Ltd.), and the following evaluation was performed. Table 5 shows the results.

(Remaining Color of Non-Image Area) After developing the unexposed area for the remaining color, the lithographic printing plate precursor was transferred to a Heidel printing machine SOR.
When the sheet was attached to -M and 50 sheets were printed, it was visually confirmed whether or not the ink was stained in the unexposed area, and evaluated as follows. 〇: No ink stain. ×: Stained with ink.

(Adhesion test) Adhesion was measured by using R201 manufactured by Roland as a printing machine and GEOS-G (N) manufactured by Dainippon Ink and Chemicals as an ink. 5 from the start of printing
On the 000 th sheet, PS plate cleaner CL-2 manufactured by Fuji Photo Film Co., Ltd. was soaked into a printing sponge, halftone dots were wiped off, and the ink on the plate surface was washed. Then, 100,
After printing 000 sheets, the presence or absence of halftone dot skipping in the printed matter was visually observed and evaluated according to the following criteria. 〇: No version skip ×: Version skip

(Evaluation of Printing Durability) Printing was performed on high quality paper using an R201 printing machine manufactured by Roland as a printing machine and using GEOS-G (N) manufactured by Dainippon Ink Co., Ltd. as an ink. The solid image area of the obtained printed matter was observed, and the number of sheets where the image area to which ink originally adhered began to fade was counted. The greater the number, the better the printing durability.
Table 5 also shows these results.

[0169]

[Table 5]

From the results shown in Table 5, the lithographic printing plate precursor according to the present invention has high solubility in the non-image portion of the alkali developing solution, has no non-image portion stain due to poor development, and has no image portion. It can be seen that the photosensitive layer has excellent adhesion and printing durability. On the other hand, Comparative Examples 1, 4, and 6 without the intermediate layer
The lithographic printing plate precursors of the above are excellent in printing durability, but inferior in solubility of non-images, easily cause stains in non-image areas, and Comparative Examples 2, 5, and 7 in which a photosensitive layer is directly provided on a silicate-treated substrate. Was inferior in printing durability. Also, JP-A-10-69092
In Comparative Example 3 provided with an intermediate layer made of a polymer described in Japanese Patent Application Laid-Open Publication No. H08-187, it was found that although the printing durability was slightly improved, there was a problem in non-image area staining.

(Examples 16 to 20, Comparative Examples 8 to 10) Polyvinyl alcohol (degree of saponification: 98) was formed on the photosensitive layer of the lithographic printing plate precursor obtained in Examples 1 to 5 and Comparative Examples 1 to 3.
Mol%, polymerization degree: 550) in an amount of 2 g / m ² after drying.
After drying for 5 minutes, a lithographic printing plate precursor having a protective layer provided on the photosensitive layer was obtained, and Examples 16 to 20 and Comparative Examples 8 to 10, respectively. The resulting lithographic printing plate precursor was exposed and developed under the same conditions as in Examples 1 to 5 and Comparative Examples 1 to 3 to make a lithographic printing plate. The adhesion and printing durability were evaluated. The results are shown in Table 6 below.

[0172]

[Table 6]

From the results shown in Table 6, when the protective layer was provided on the photosensitive layer, the same tendency as in Examples 1 to 5 having no protective layer was observed. , The non-image area has high solubility in an alkali developing solution, there is no occurrence of non-image area contamination due to poor development, and the adhesiveness of the photosensitive layer in the image area and the printing durability are excellent. The lithographic printing plate precursor of Comparative Example 8, which was not provided with, was excellent in printing durability, but inferior in non-image solubility, and Comparative Example 9, in which a photosensitive layer was directly provided on a silicate-treated substrate, was inferior in printing durability. I understand. Further, it can be seen that Comparative Example 10 in which an intermediate layer made of a polymer described in JP-A-10-69092 is provided also has a problem of non-image area stain even when a protective layer is provided.

[0174]

The negative type lithographic printing plate precursor according to the present invention can be written with an infrared laser, has excellent adhesion to the substrate and the photosensitive layer in the image area, and has stains due to poor development in the non-image area. This is advantageous in that it is difficult to perform printing and has excellent image reproducibility and printing durability.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuto Kunida 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Pref. AA06 BA05 CA03 CA05 EA04 EA23

Claims (1)

[Claims] 1. An intermediate layer containing a polymer having an acid group and an onium group on an anodized aluminum support, I) an infrared absorber, II) a polymerization initiator, and III)
A lithographic printing plate precursor adapted for a heat mode, comprising: a compound having a polymerizable unsaturated group; and IV) a photosensitive layer containing a water-insoluble and aqueous alkali-soluble binder.