JP2008233496A - Photosensitive lithographic printing plate original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate original plate for infrared laser in which ablation of an exposed area is suppressed, while retaining developability and sensitivity at practically proper levels. <P>SOLUTION: The photosensitive lithographic printing plate original plate for an infrared laser is obtained, by disposing a recording layer on a support having a hydrophilic surface, wherein the recording layer contains (a) an infrared absorbent and (b) an acrylic resin containing 50-95 mol% of a polymerizable monomer, selected from either ethyl (meth)acrylate and propyl (meth)acrylate and a polymerizable monomer having an acid group as polymerized components. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive lithographic printing plate precursor and a method for producing a lithographic printing plate. More specifically, the present invention relates to a photosensitive lithographic plate capable of direct plate making by scanning with infrared laser light based on a digital signal from a computer or the like. It relates to the printing version.

  In recent years, the development of lasers has been remarkable, and in particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared region have been increasing in output and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.

  The so-called lithographic printing plate material for infrared laser, which uses an infrared laser having a light emitting region in the infrared region as an exposure light source, is a lithographic printing comprising a binder resin and an IR dye that absorbs light and generates heat as essential components. It is a plate material. When the infrared laser is exposed to the lithographic printing plate material for infrared laser, in the case of a positive type, the IR dye or the like in the lithographic printing plate material for infrared laser is in mutual contact with the binder resin in an unexposed portion (image portion). It acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by the action. On the other hand, in the exposed portion (non-image portion), the IR dye or the like absorbs light and generates heat, so that the interaction between the IR dye or the like and the binder resin is weakened. Therefore, at the time of development, the exposed portion (non-image portion) is dissolved in an alkaline developer, and a lithographic printing plate is formed.

  In the lithographic printing plate material for infrared laser, there is a phenomenon called ablation in which the recording layer component in the exposed portion is scattered by heat generated during exposure. When ablation occurs frequently, the scattered matter adheres to the surface of the printing plate being exposed, the surface of the laser light source, and the like, thereby causing exposure inhibition. In addition, since the frequency of maintenance increases, it is preferable that the amount of ablation is small.

  In order to suppress ablation, for example, use a phenolic hydroxyl group-containing compound having 4 or more aromatic rings in the molecule (see Patent Document 1), or control the content of low molecular weight components of the novolak resin used. (See Patent Document 2), or use of an alkali-soluble novolak resin containing xylenol as a structural unit (see Patent Document 3) has been proposed. All of these have an effect of suppressing ablation, but have problems such as insufficient developability and insufficient sensitivity, and further improvements have been desired.

JP 2002-214767 A JP 2002-323755 A JP 2002-357894 A

  An object of the present invention is to provide a photosensitive lithographic printing plate precursor for an infrared laser in which the ablation amount in an exposed portion is suppressed while maintaining developability and sensitivity at a practically good level.

As a result of intensive studies, the present inventor has found that the above-described problems can be achieved by the following photosensitive lithographic printing plate precursor for infrared laser.
That is, the photosensitive lithographic printing plate precursor for infrared laser of the present invention is a photosensitive lithographic printing plate precursor for infrared laser in which a recording layer is provided on a support having a hydrophilic surface, and the recording layer comprises (a ) An infrared absorber, and (b) an acrylic resin containing, as polymerization components, 50 to 95 mol% of a polymerizable monomer selected from ethyl (meth) acrylate and propyl (meth) acrylate and a polymerizable monomer having an acid group, It is characterized by containing.

Furthermore, the photosensitive lithographic printing plate precursor for infrared laser according to the present invention is a photosensitive lithographic printing plate for infrared laser in which a recording layer having a multilayer structure in which a plurality of recording layers are laminated on a support having a hydrophilic surface is provided. In the original plate, the outermost recording layer of the recording layer is (a) an infrared absorber, and (b) a polymerizable monomer 50 to 95 selected from ethyl (meth) acrylate and propyl (meth) acrylate. It contains an acrylic resin containing a mol% and a polymerizable monomer having an acid group as a polymerization component.
(Meth) acrylate in the present invention means either or both of acrylate and methacrylate.

  According to the present invention, it is possible to provide a photosensitive lithographic printing plate precursor for an infrared laser in which the ablation amount of an exposed portion is suppressed while maintaining developability and sensitivity at a practically good level.

The photosensitive lithographic printing plate precursor for infrared laser according to the present invention is a photosensitive lithographic printing plate precursor for infrared laser in which at least one recording layer is provided on a support having a hydrophilic surface, and the recording layer comprises (a ) An infrared absorber, (b) an acrylic resin, wherein the (b) acrylic resin has a polymerizable monomer having an alkyl (meth) acrylate having 2 to 3 carbon atoms, a polymerizable monomer having an acid group, The copolymer is characterized in that the content of the alkyl (meth) acrylate having 2 to 3 carbon atoms in the copolymer is from 50 mol% to 95 mol%.
Further, when the recording layer has a multilayer structure, the outermost recording layer of the recording layers has the above-described configuration.

The photosensitive lithographic printing plate precursor according to the present invention having the above-described configuration can suppress the ablation amount of the exposed portion while maintaining developability and sensitivity at a practically good level. The reason for this is not clear, but is considered as follows.
That is, in the present invention, an acrylic resin is contained in the recording layer, and the acrylic resin has a specific structure, that is, an alkyl (meth) acrylate having 2 to 3 carbon atoms in an amount of 50 mol% to 95 mol%. It is considered that the structure in the resin plays a role like an adhesive in the recording layer and functions to suppress ablation. Moreover, it is thought that the solubility to an alkali developing solution was able to be ensured by containing the polymerizable monomer which has an acid group in an acrylic resin. This is because the exposed portion (non-image portion) absorbs light by infrared irradiation to generate heat, and (a) the polymerization between the acid absorber and (b) the acrylic resin is weakened by weakening the interaction between the acrylic absorber and (b) the acrylic resin. It is considered that the solubility in an alkali developer is improved by the action of the acid group inherent to the functional monomer.

The recording layer according to the present invention contains (a) an infrared absorber and (b) an acrylic resin.
Below, each item is demonstrated one by one.
<(B) Acrylic resin>
The acrylic resin contained in the recording layer, particularly the outermost recording layer in the case of a multilayer structure, is a copolymer of a polymerizable monomer having an alkyl (meth) acrylate having 2 to 3 carbon atoms and a polymerizable monomer having an acid group. The copolymer is characterized in that the content of the alkyl (meth) acrylate having 2 to 3 carbon atoms in the copolymer is from 50 mol% to 95 mol%.

An alkyl group having 2 to 3 carbon atoms means an ethyl group or a propyl group.
The propyl group may be linear or branched.

Specific examples of the alkyl (meth) acrylate having 2 to 3 carbon atoms include ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, i-propyl acrylate and i-propyl methacrylate. Of these, ethyl methacrylate, n-propyl methacrylate, and i-propyl methacrylate are preferable, and ethyl methacrylate is most preferable.
These may be used alone or in combination of two or more.

  The weight ratio of ethyl (meth) acrylate or propyl (meth) acrylate to the total amount of acrylic resin is 50 mol% or more and 95 mol% or less, more preferably 55 mol% or more and 95 mol% or less, and still more preferably 55 mol%. More than 90 mol%. When the ratio is less than 50 mol%, the ablation suppression effect and the development resistance effect are lowered. Further, the ratio of the polymerizable monomer having an acid group is relatively increased, and the surface of the image area may be easily damaged during development. On the other hand, when the ratio is larger than 95 mol%, the ratio of the polymerizable monomer having an acid group is relatively decreased, and the developability is deteriorated.

Examples of the acid group in the polymerizable monomer having an acid group contained in the acrylic resin include the acid groups listed in the following (1) to (6).
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) phosphoric acid group (-OPO ₃ H ₂₎

In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent.
As a polymerizable monomer which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the polymerizable monomer having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.
(2) The polymerizable monomer having a sulfonamide group is preferably a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule. For example, the monomer represented by the following general formula (i)-general formula (v) is mentioned.

In general formulas (i) to (v), X ¹ and X ² each independently represent —O— or —NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² and R ¹⁶ are each independently an alkylene group having 1 to 12 carbon atoms which may have a substituent, and an optionally substituted carbon number. 1 to 12 cycloalkylene group, an optionally substituted arylene group having 1 to 12 carbon atoms or an optionally substituted aralkylene group having 1 to 12 carbon atoms.

R ³ , R ⁷ , and R ¹³ are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, or an optionally substituted carbon atom having 1 to 12 carbon atoms. A cycloalkyl group, an aryl group having 1 to 12 carbon atoms which may have a substituent, or an aralkyl group having 1 to 12 carbon atoms which may have a substituent.

R ⁶ and R ¹⁷ are each independently an optionally substituted alkyl group having 1 to 12 carbon atoms, an optionally substituted cycloalkyl group having 1 to 12 carbon atoms, and a substituent. The C1-C12 aryl group which may have a group, and the C1-C12 aralkyl group which may have a substituent are represented.

R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ are each independently a single bond or an optionally substituted alkylene group having 1 to 12 carbon atoms, an optionally substituted cycloalkylene group having 1 to 12 carbon atoms, The C1-C12 arylene group which may have a substituent, or the C1-C12 aralkylene group which may have a substituent is represented. Y ¹ and Y ² each independently represent a single bond or CO.

  (3) Examples of the polymerizable monomer having an active imide group include monomers having one or more active imide groups represented by the following structural formula and one or more polymerizable unsaturated groups in the molecule.

Specific examples include N- (p-toluenesulfonyl) methacrylamide and N- (p-toluenesulfonyl) acrylamide.
(4) Examples of the polymerizable monomer having a carboxylic acid group include acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

(5) Examples of the polymerizable monomer having a sulfonic acid group include acrylamide, methacrylamide, acrylic acid ester, and methacrylic acid ester having an alkylsulfonic acid group.
(6) Examples of the polymerizable monomer having a phosphoric acid group include acrylamide, methacrylamide, acrylic acid ester, and methacrylic acid ester having an alkyl phosphoric acid group.

Among the polymerizable monomers having an acidic group selected from (1) to (6) above, (1) a polymerizable monomer having a phenol group, (4) a carboxylic acid group, and (5) a sulfonic acid group is preferable. (1) A polymerizable monomer having a phenol group and (4) a carboxylic acid group is most preferred.
In addition, the polymerizable monomer having an acidic group selected from the above (1) to (6) is not particularly limited to one type, and two or more polymerizable monomers having the same acidic group or different acidic groups are included. What copolymerized 2 or more types of polymerizable monomers can be used.

  The polymerizable monomer having an acid group is preferably contained in the acrylic resin (b) in an amount of 5 mol% to 50 mol%, more preferably 10 mol% to 45 mol%. If it is less than 5 mol%, the solubility in an alkaline developer containing substantially no solvent may be reduced. On the other hand, if it exceeds 50 mol%, the effect of suppressing ablation is reduced, and the surface of the image area is easily damaged during development.

In the present application, examples of the composition (b) composition [composition A to composition N] of (b) acrylic resin that is suitably used are shown below. In addition, the numerical value of a composition ratio represents mol%.
Composition (A) Ethyl acrylate / acrylic acid = 70/30
Composition (B) ethyl acrylate / methacrylic acid = 80/20
Composition (C) Ethyl methacrylate / acrylic acid = 90/10
Composition (D) Ethyl methacrylate / methacrylic acid = 65/35
Composition (E) n-propyl methacrylate / methacrylic acid = 75/25
Composition (F) n-propyl methacrylate / acrylic acid = 85/15
Composition (G) i-propyl methacrylate / methacrylic acid = 60/40
Composition (H) i-propyl methacrylate / acrylic acid = 55/45
Composition (I) n-propyl methacrylate / ethyl methacrylate / methacrylic acid = 55/15/30
Composition (J) i-propyl methacrylate / ethyl methacrylate / methacrylic acid = 5/60/35
Composition (K) n-propyl methacrylate / itaconic acid = 50/50
Composition (L) Ethyl methacrylate / 2- (p-hydroxyphenyl) ethyl methacrylate = 60/40
Composition (M) i-propyl methacrylate / methacrylic acid / 2- (p-hydroxyphenyl) ethyl methacrylate = 75/20/5
Composition (N) i-propyl methacrylate / ethyl methacrylate / methacrylic acid / 2- (p-hydroxyphenyl) ethyl methacrylate = 10/60/20/10

  The weight average molecular weight of these (b) acrylic resins measured by GPC is preferably 5,000 to 500,000, more preferably 7,000 to 300,000, and even more preferably 10,000 to 200,000. is there. If the molecular weight is small, the effect of suppressing ablation is small, which is not preferable.

  In the present invention, the amount of (b) acrylic resin added is preferably 1 to 30% by weight, more preferably 2 to 25% by weight, and further preferably 3 to 20% by weight with respect to the total amount of the recording layer. (B) If the amount of the acrylic resin added is less than 1% by weight, the effect of suppressing ablation cannot be sufficiently exerted, and if it exceeds 30% by weight, other components contained in the recording layer, particularly the infrared absorber described later, This is not preferable because the amount added decreases and sensitivity decreases.

<Other polymer compounds>
The recording layer of the photosensitive lithographic printing plate precursor according to the invention preferably contains another polymer compound in addition to (b) the acrylic resin. Although the preferable example of another high molecular compound is described below, if it is resin which satisfy | fills this condition, it will not specifically limit.

The other polymer compound used in the present invention is preferably (c) an alkali-soluble or swellable polymer compound from the viewpoint of ensuring developability. Examples of such a polymer compound include polymer compounds having the acidic groups listed in the following (1) to (6) in the main chain and / or side chain of the polymer.
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) phosphoric acid group (-OPO ₃ H ₂₎

In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent.
As a high molecular compound which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.

  (1) Examples of the polymer compound having a phenol group include novolak resins, xylenol resins, and resole resins. Specifically, phenol formaldehyde resins, m-cresol formaldehyde resins, p-cresol formaldehyde resins, m // p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed) mixed formaldehyde resin, 1,2-xylenol, 1,3-xylenol, 1,4-xylenol, 1,5-xylenol, 2,3-xylenol, 2,4-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak mixed resin, xylenol / Novolac / Phenol mixed resin and Pi Mention may be made of the condensation polymers of Garoru and acetone. In addition, a polymer compound obtained by copolymerizing a compound having a phenol group in the side chain can also be mentioned, and acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, or hydroxystyrene having a phenol group can be used as a copolymer component. High molecular compounds.

  (2) As a polymer compound having a sulfonamide group, for example, a polymer composed of a minimum structural unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among them, a monomer having a structure derived from a low molecular weight compound having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. -The thing of the structure similar to the monomer represented by general formula (v) is mentioned.

  Among the compounds represented by the general formula (i) to the general formula (v), in the photosensitive lithographic printing plate precursor according to the invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide , N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) As a high molecular compound which has an active imide group, the polymer comprised as a main structural component the minimum structural unit derived from the compound which has an active imide group can be mentioned, for example. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.
(4) As a high molecular compound having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and one or more polymerizable unsaturated groups in the molecule is used as a main constituent component. A polymer can be mentioned. In the photosensitive lithographic printing plate precursor according to the invention, acrylic acid, methacrylic acid, maleic acid and itaconic acid can be preferably used.

(5) As a high molecular compound having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and polymerizable unsaturated group in the molecule is used as a main structural unit. A polymer can be mentioned.
(6) As a high molecular compound having a phosphoric acid group, for example, a minimum structural unit derived from a compound having at least one phosphoric acid group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

In addition to the above, a polymer using an unsaturated compound having an acidic group of (1) to (6) in the side chain and having a urea bond as a linking group can also be used.
Among the polymer compounds having an acidic group selected from (1) to (6) above, (1) a phenol group, (2) a sulfonamide group, (3) an active imide group, and (4) a carboxylic acid group Molecular compounds are preferred, and in particular, a polymer compound having (1) a phenol group, (2) a sulfonamide group or (4) a carboxylic acid group is most preferred.

  Further, the minimum structural unit having an acidic group selected from the above (1) to (6) is not particularly limited to one kind, and has two or more minimum structural units having the same acidic group or different acidic groups. What copolymerized 2 or more types of the minimum structural unit can be used.

  When the other polymer compound (c) that can be used in combination is a copolymer, the compound having an acidic group selected from (1) to (6) to be copolymerized is 3 mol% to 50 mol in the copolymer. % Or less is preferable, and 5 mol% or more and 45 mol% or less is more preferable. If it is less than 3 mol%, the solubility in an alkaline developer containing substantially no solvent will decrease. On the other hand, if it exceeds 50 mol%, the surface of the image area is easily damaged during development.

As the monomer component to be copolymerized with the polymerizable monomer having an acidic group, for example, monomers listed in the following (m1) to (m11) can be used, but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.

(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-phenylmaleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

  Although the high molecular compound in this invention may be used individually by 1 type, you may use together 2 or more types of different high molecular compounds.

  Of the polymer compounds exemplified above, novolak resins and xylenol resins are preferably used, and phenol formaldehyde resins, m-cresol formaldehyde resins, p-cresol formaldehyde resins, m- / p-mixed cresol formaldehyde resins, phenol / Cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed) mixed formaldehyde resin, 1,2-xylenol, 1,3- Xylenol, 1,4-xylenol, 1,5-xylenol, 2,3-xylenol, 2,4-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak mixed resin, xylenol / novolak / phenol mixed resin, etc. Can do.

  In addition, a polymer compound having a sulfonamide group or a carboxylic acid group is also preferably used, and is preferably a copolymer. As the component of the copolymer, alkyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile and the like are preferably used, but a small amount of the above-mentioned monomer components may be contained. Furthermore, a copolymer containing maleimide as a constituent component such as N-phenylmaleimide is also particularly preferably used as the polymer compound. The copolymer component includes alkyl (meth) acrylate, (meth) acrylamide, (meta ) Acrylonitrile and the like are used, but a small amount of the above-mentioned monomer components may be contained.

  In the present invention, when the other polymer compound is a resin such as phenol formaldehyde resin or cresol aldehyde resin, the weight average molecular weight measured by GPC is preferably 500 to 20,000, more preferably 1,000 to 18,000. 1,500 to 15,000 is more preferable. The number average molecular weight is preferably 200 to 10,000, more preferably 300 to 10,000, and still more preferably 500 to 8,000.

In the case of other polymer compounds other than those described above, the weight average molecular weight measured by GPC is preferably 2,000 or more and the number average molecular weight is 500 or more, more preferably the weight average molecular weight is 5,000 to 300, The number average molecular weight is 800 to 250,000, more preferably the weight average molecular weight is 7,000 to 250,000, and the number average molecular weight is 1,000 to 200,000.
The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10, more preferably 1.1 to 8, and still more preferably 1.2 to 7.

  In the present invention, the amount of other polymer compound added is preferably from 30 to 99% by weight, more preferably from 50 to 99% by weight, particularly preferably from 65 to 99% by weight, based on the total amount of the recording layer. When the amount of other polymer compound added is less than 30% by weight, the durability of the recording layer may be deteriorated. When the amount exceeds 99% by weight, the amount of the infrared absorber described later decreases and sensitivity increases. Since it falls, it is not preferable.

<(A) Infrared absorber>
The positive recording layer of the present invention contains an infrared absorber that exhibits a photothermal conversion function. This infrared absorber has a function of converting the absorbed infrared rays into heat, and the release of the interaction, decomposition of the development inhibitor, generation of acid, etc. occur in the positive recording layer by infrared laser scanning, The solubility in the developer is greatly increased. In addition, the infrared absorber itself may interact with the alkali-soluble resin to suppress alkali solubility.
The infrared absorber used in the present invention is a dye or pigment that effectively absorbs infrared rays having a wavelength of 760 nm to 1200 nm. A dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.
Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” Examples thereof include pigments described in "Ink Technology" (published by CMC Publishing, 1984).

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

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

  The particle diameter of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.1 to 1 μm. If the particle size of the pigment is less than 0.01 μm, it may not be preferable in terms of the stability of the dispersion in the recording layer coating solution, whereas if it exceeds 10 μm, the recording layer is uniform. It may not be preferable in terms of sex.

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

  Examples of the dye include commercially available dyes and known dyes described in literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970), such as azo dyes, metal complex azo dyes, pyrazolone azos. And dyes such as dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes.

  From the viewpoint of being suitable for use in a laser emitting infrared light or near infrared light, among the pigments or dyes, pigments and dyes that absorb infrared light or near infrared light are particularly preferable.

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

Further, as the dye, a near-infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and substituted arylbenzo (described in US Pat. No. 3,881,924) Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US Pat. The pentamethine thiopyrylium salt described in No. 283,475 and the pyrilylation disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 Things, EpolightIII-178, EpolightIII-130, Epolight III-125, EpolightV-176A or the like is used particularly preferably.
Moreover, as said dye, as another especially preferable example, the near-infrared absorptive dye described as U.S. Pat. No. 4,756,993 as the formulas (I) and (II) can be mentioned.

The amount of the pigment or dye added is preferably 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, based on the total solid content of the printing plate material. In the case of the dye, 0.5 to 10% by weight is particularly preferable, and in the case of a pigment, 3.1 to 10% by weight is particularly preferable.
When the amount of the pigment or dye added is less than 0.01% by weight, the sensitivity may be lowered. On the other hand, when it exceeds 50% by weight, the uniformity of the recording layer is lost, and the recording layer Durability may deteriorate.

<Other ingredients>
Various additives can be further added to the recording layer in the present invention as necessary. Specifically, in order to adjust the solubility of the recording layer, for example, an onium salt, an aromatic sulfone compound, An aromatic sulfonic acid ester compound, a polyfunctional amine compound, etc. can be added.
In addition, it is preferable to add a so-called dissolution inhibitor that improves the function of preventing dissolution of the alkaline water-soluble polymer (alkali-soluble resin) in the developer. Among them, it is possible to use together a substance that is thermally decomposable, such as an onium salt, an o-quinonediazide compound, and a sulfonic acid alkyl ester, and that substantially reduces the solubility of the alkali-soluble resin when not decomposed. It is preferable at the point which can control the dissolution inhibitory property to.

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

Among these onium salts, a diazonium salt, a quaternary ammonium salt, and a sulfonium salt are particularly preferable from the viewpoint of dissolution inhibiting ability and thermal decomposability.
In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable.

Further, as the quaternary ammonium salt, the quaternary ammonium represented by [Chemical Formula 4] and [Chemical Formula 5] specific examples (1) to (10) described in paragraphs [0020] and [0021] of JP-A-2002-229186 are disclosed. Salts are preferred. Moreover, as a sulfonium salt, the sulfonium salt shown by [Chemical formula 6] general formula (II) of paragraph number [0043] of Unexamined-Japanese-Patent No. 2005-266003 is preferable.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, alkyl aromatic sulfonic acids such as 2,5-dimethylbenzenesulfonic acid, and 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid are particularly preferable. It is.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance.

  Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17478, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

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

  The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and still more preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

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

  Moreover, in the photosensitive composition of this invention, cyclic acid anhydrides, phenols, and organic acids can be used together for the purpose of improving a sensitivity. Further, a surfactant, an image colorant, and a plasticizer described later can also be used in the positive recording layer of the present invention.

  Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.

  The proportion of the cyclic acid anhydride, phenols, and organic acids in the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by mass.

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

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

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

  Furthermore, a plasticizer is added to the photosensitive composition of the present invention, if necessary, in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

<Coating solvent>
The photosensitive lithographic printing plate precursor is prepared by dissolving the above-described components in a solvent, coating the support on a support, and drying to provide a recording layer. The coating solvent used here is methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, sec-butanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl. 2-butanol, 2-ethyl-1-butanol, 1-pentanol, 2-pentanol, 3-pentanol, n-hexanol, 2-hexanol, cyclohexanol, methylcyclohexanol, 1-heptanol, 2-heptanol , 3-heptanol, 1-octanol, 4-methyl-2-pentanol, 2-hexyl alcohol, benzyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1, -Pentane glycol, dimethyltriglycol, furfuryl alcohol, hexylene glycol, hexyl ether, 3-methoxy-1-butanol, 3-methoxy-3-methylbutanol, butylphenyl ether, ethylene glycol monoacetate, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl Ether, dipropylene glycol monobutyl ether, tripropylene Recall monomethyl ether, methyl carbitol, ethyl carbitol, ethyl carbitol acetate, butyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol dimethyl ether, diacetone alcohol, acetophenone, cyclohexanone, methylcyclohexanone, Acetonylacetone, isophorone, methyl lactate, ethyl lactate, butyl lactate, propylene carbonate, phenyl acetate, sec-butyl acetate, cyclohexyl acetate, diethyl oxalate, methyl benzoate, ethyl benzoate, γ-butyrolactone,

3-methoxy-1-butanol, 4-methoxy-1-butanol, 3-ethoxy-1-butanol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-ethyl-1-pentanol, 4 -Ethoxy-1-pentanol, 5-methoxy-1-hexanol, 4-hydroxy-2-pentanone, 5-hydroxy-2-pentanone, 6-hydroxy-2-pentanone, 4-hydroxy-3-pentanone, 6- Hydroxy-2-hexanone, 3-methyl-3-hydroxy-2-pentanone, methyl cellosolve (MC), ethyl cellosolve (EC), allyl alcohol, isopropyl ether, butyl ether, anisole, propylene glycol monomethyl ether acetate, diethyl carb Tolu, tetrahydrofuran, dioxane Dioxolane, acetone, methyl propyl ketone, methyl ethyl ketone, methyl amyl ketone, diethyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, 3-hydroxy-2-butanone, 4-hydroxy-2-butanone, 2-methoxyethyl acetate , 2-ethoxyethyl acetate, methoxybutyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, N-methyl-2-pyrrolidone, acetonitrile, dimethylformamide (DMF), dimethyl Acetamide (DMAc), n-pentane, 2-methylpentane, 3-ethylpentane, methylcyclopentane, n-hexane, isohexane, cyclohexane, methylcyclohexane, n-heptane, cyclohexane Tan, n-octane, isooctane, nonane, decane, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, cumene, n-amylbenzene, dimethyl Solvents such as sulfoxide (DMSO) and dimethyldiglycol (DMDG) are used alone or in combination of two or more.
In the photosensitive composition solution using these (mixed) solvents, the concentration of the total solid content in the solvent is 1 to 50% by mass, preferably 1 to 30% by mass.

<Application method, etc.>
The photosensitive lithographic printing plate precursor according to the present invention can be produced by applying the above-described photosensitive composition solution onto a suitable support. Depending on the purpose, a protective layer, a resin intermediate layer, A back coat layer and the like can be formed in the same manner.

  Various methods can be used for applying the recording layer coating liquid. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating, etc. Can be mentioned. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer film deteriorate.

-Layer structure of recording layer-
The recording layer of the photosensitive lithographic printing plate precursor according to the invention can be used in any of a single layer structure, a phase separation structure, and a multilayer structure.
As the single-layer recording layer, for example, a recording layer described in JP-A-7-285275, WO 97/39894, and as a phase-separated recording layer, for example, a recording layer described in JP-A-11-44956, As the multi-layer recording layer, for example, the recording described in JP-A No. 11-218914, US Pat. No. 6,352,812 B1, US Pat. No. 6,352,811 B1, US Pat. No. 6,358,669 B1, US Pat. No. 6,534,238 B1, and European Patent No. 864420 B1. Layers can be used, but are not limited to these.
In the case of the multilayer structure, the (b) acrylic resin and (a) infrared absorber of the present invention are contained in the outermost recording layer, but one or both of them are contained in a layer other than the outermost surface. May be. Moreover, when (b) acrylic resin and (c) other polymer compounds are contained in a plurality of layers, these may be the same or different.

In the case of a single layer, the solid content coating amount obtained after coating and drying is preferably 0.3 to 5.0 g / m ² , more preferably 0.5 to 3.0 g / m ² . In the case of multiple layers, the upper layer is preferably 0.05 to 2.0 g / m ² and the lower layer is preferably 0.3 to 5.0 g / m ² , more preferably the upper layer is 0.1 to 1.0 g / m ^2. The lower layer is in the range of 0.5 to 3.0 g / m ² . Moreover, 0.05-1 are preferable and, as for ratio of the coating amount of an upper layer and a lower layer, More preferably, it is the range of 0.1-0.8.

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

  As the support that can be applied to the photosensitive lithographic printing plate precursor, a polyester film or an aluminum plate is preferable. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.

  Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.12 mm to 0.4 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. Among these, it is preferable to include a step of roughening at least in a hydrochloric acid electrolyte.

The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image portion of the planographic printing plate is easily damaged, and ink adheres to the damaged portion during printing. So-called “scratch stains” easily occur.

  After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

<Undercoat layer>
The photosensitive lithographic printing plate precursor according to the present invention is provided with an image recording layer as described above on a support, and an undercoat layer can be provided between the support and the lower layer as necessary. . By providing this undercoat layer, the undercoat layer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, there is an advantage that high sensitivity can be achieved. In addition, since the recording layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, the sensitivity to the infrared laser is maintained well.

  In the unexposed area, the recording layer itself that is impermeable to the alkaline developer functions as a protective layer for the undercoat layer, so that the development stability is good and the image is excellent in discrimination. It is considered that stability over time is secured. In the exposed area, the components of the recording layer whose dissolution-inhibiting ability is released are quickly dissolved and dispersed in the developer, and the undercoat layer itself that is adjacent to the support is made of an alkali-soluble polymer. Therefore, the solubility in the developer is good.For example, even when a developer with reduced activity is used, it dissolves quickly without the formation of a residual film, contributing to the improvement of the developability. This subbing layer is considered useful.

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

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

R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent, and R ¹² and R ¹³ each independently have a hydrogen atom, a hydroxyl group, a halogen atom or a substituent. alkyl group, an aryl group which may have a substituent, -OR ^14, -COOR ^15, represents a -CONHR ^16, -COR ¹⁷ or -CN. R ¹² and R ¹³ may combine to form a ring. R ^{14 to} R ¹⁷ each independently represents an alkyl group which may have a substituent or an aryl group which may have a substituent. X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently have a hydrogen atom, an alkyl group that may have a substituent, or a substituent. Represents an aryl group which may be substituted, and R ¹⁸ and R ¹⁹ may combine to form a ring. m represents an integer of 1 to 3.

Moreover, as a suitable undercoat layer component in the present invention, a polymer compound containing a compound having an acid group and a compound having an onium group described in JP-A No. 2000-241962 can be exemplified.
Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH.

Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group.
Preferred as the onium salt is an onium group comprising atoms of Group V or VI of the periodic table, more preferred is an onium salt comprising nitrogen, phosphorus or sulfur atoms, and particularly preferred is an onium salt comprising nitrogen atoms. Salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as methacrylate, methacrylamide, or quaternary ammonium group having an ammonium group in the side chain.

  Furthermore, compounds such as those described in JP-A No. 2000-108538, Japanese Patent Application No. 2002-257484, Japanese Patent Application No. 2003-78699, and the like can be used as an undercoat layer component as necessary. it can.

  The undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, and then washed and dried with water or the like to provide an undercoat layer.

In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute.
The solution used for the undercoat layer can be adjusted to a pH range of 1 to 12 with a basic substance such as ammonia, triethylamine, potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.

The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . Sufficient printing durability can be obtained by setting the above range.

<Exposure>
The photosensitive lithographic printing plate of the present invention is imaged by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy irradiated to the recording material is preferably 10 to 500 mJ / cm 2.

<Development>
In the present invention, the exposed photosensitive lithographic printing plate is preferably developed with an alkaline aqueous solution having a pH of 12 or higher that does not substantially contain an organic solvent. Here, “substantially free of organic solvent” means that it does not contain an organic solvent to the extent of causing inconvenience in terms of environmental health, safety, workability, etc. The ratio of the organic solvent in the developer is 0.5% by weight or less, preferably 0.3% by weight or less, and most preferably not contained at all. Moreover, although pH is 12.0 or more, More preferably, it is 12.0-14.0.

  A conventionally known alkaline aqueous solution can be used as the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

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

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

  In addition, a so-called “non-silicate developer” that does not contain an alkali silicate and contains a non-reducing sugar and a base can also be suitably used. In this case, it is preferable to contain a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Non-reducing sugars are saccharides that do not have a free aldehyde group or ketone group and do not exhibit reducibility, trehalose-type oligosaccharides in which reducing groups are bonded, and glycosides in which reducing groups of saccharides are combined with non-saccharides. , And sugar alcohols reduced by hydrogenation of sugars, any of which can be used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

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

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

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

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

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

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

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

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

The image forming material developed using the developer and the replenisher is post-processed with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As the post-treatment when the image forming material is used as a printing plate, these treatments can be used in various combinations.
Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of developer can be obtained without replacing the developer in the developer tank for a long time. It is known that PS plates can be processed. This replenishment method is also preferably applied in the present invention.

  The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the lithographic printing plate precursor using the photosensitive composition of the present invention, these treatments can be used in various combinations.

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

  In the lithographic printing plate precursor using the photosensitive composition of the present invention, an image portion unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, If there is a film edge mark of the original image film, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to make a lithographic printing plate with a higher printing durability, if desired, Burning process is performed.
In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.

As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.
In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

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

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

(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

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

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

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

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

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

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

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

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

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

(J) Anodizing treatment As the electrolytic solution, sulfuric acid having a temperature of 43 ° C. and a concentration of 170 g / liter (containing 0.5 mass% of aluminum ions) was used. The current density was about 30 A / dm ² and the final oxide film amount was 2.7 g / m ² . Thereafter, washing with water was performed using well water.
The supports A to D shown below were produced by combining the steps (a) to (j) described above.

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

<Support B>
A support B was prepared by sequentially performing the steps except that the steps (g), (h), and (i) were omitted.

<Support C>
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.

<Support D>
Of the above steps, the steps (a) and (d) (e) (f) are omitted except that the steps are performed in order, and the total amount of electricity in the step (g) is 450 C / dm ² for support. Body D was prepared.

  The supports A to D thus obtained were subsequently subjected to silicate treatment and undercoat formation as shown in (k) below.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment is immersed in a treatment layer of a 1% by mass aqueous solution of No. 1 sodium silicate at a temperature of 30 ° C. for 10 seconds to obtain an alkali metal silicate. Processing (silicate processing) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate attached was 5.5 mg / m ² .

[Formation of undercoat]
First, the following undercoat liquid (1) was applied to the aluminum plate thus treated using a wire bar, and then dried at 80 ° C. for 20 seconds. The coating amount after drying was 0.02 g / m ² .
Undercoat liquid (1)
-Compound (weight average molecular weight 150,000, following formula) 0.1 g
・ Methanol 100.0g

  After the undercoat liquid (1) was applied to an aluminum plate and dried, a photosensitive lithographic printing plate precursor was prepared by any one of methods 1 to 4 for forming a recording layer described later.

[Formation of recording layer 1]
The coating liquid A having the following composition is applied to the support provided with the intermediate layer with a wire bar, and then dried in a drying oven at 150 ° C. for 40 seconds so that the coating amount becomes 0.8 g / m ^2. Was provided.
Moreover, after providing a lower layer, the coating liquid B of the following composition was apply | coated with the wire bar. After coating, drying was performed at 150 ° C. for 40 seconds to obtain a photosensitive lithographic printing plate in which the component of the coating solution B was an upper layer so that the total coating amount of the lower layer and the upper layer was 1.0 g / m ² .

<Coating liquid A>
N- (p-aminosulfonylphenyl) methacrylamide / methyl methacrylate / acrylonitrile = 35/35/30 (molar ratio) copolymer (weight average molecular weight 65,000) 3.5 g
M, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 6000)
0.6g
・ Infrared absorber (cyanine dye A, the following formula) 0.25 g
0.15 g of a dye in which the counter anion of ethyl violet is 6-hydroxy-β-naphthalenesulfonic acid
・ Bisphenolsulfone 0.3g
・ Tetrahydrophthalic acid 0.4g
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02g
・ Methyl ethyl ketone 60g
・ Propylene glycol monomethyl ether 20g
・ Γ-Butyrolactone 20g

<Coating liquid B>
Novolak resin (m-cresol / p-cresol / phenol = 3/2/5, weight average molecular weight 8000) 1.7 g
-(A) Infrared absorber (cyanine dye A, the above formula) 0.15 g
Compound Q (following formula) 0.35 g
・ Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.03g
Tridecafluorooctyl methacrylate / 2-adamantyl acrylate / 2-carboxyethyl methacrylate = 30/50/20 (copolymer having a weight average molecular weight of 30,000) 0.1 g
・ (B) Acrylic resin 0.3g
(Compound having the composition and weight average molecular weight shown in Table 1)
・ Methyl ethyl ketone 33.0g
・ 6-Methoxy-2-propanol 67.0g

[Recording layer formation 2]
After coating the coating liquid C having the following composition on the support provided with the intermediate layer with a wire bar, the lower layer is coated so that the coating amount is 1.3 g / m ² by drying in a drying oven at 150 ° C. for 40 seconds. Provided.
Moreover, after providing a lower layer, the coating liquid B of the said composition was apply | coated with the wire bar. After coating, drying was performed at 150 ° C. for 40 seconds so that the total coating amount became 1.8 g / m ^2, and a photosensitive lithographic printing plate was obtained.

<Coating liquid C>
-Copolymer of N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) (weight average molecular weight 50,000) 0.85 g
・ Ethyl violet 0.05g
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02g
・ Methyl ethyl ketone 5g
・ Propylene glycol monomethyl ether 15g
・ Γ-Butyrolactone 5g

[Recording Layer Formation 3]
A coating solution D having the following composition is coated on a support provided with an intermediate layer with a wire bar, and then dried in a drying oven at 160 ° C. for 40 seconds so that the coating amount is 1.20 g / m ^2. A sex lithographic printing plate was obtained.

<Coating liquid D>
-Copolymer of 2- (N ′-(4-carboxyphenyl) ureido) ethyl methacrylate / N-phenylmaleimide = 75/25 (weight ratio) (weight average molecular weight 30,000) 0.40 g
-Copolymer of N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) (weight average molecular weight 50,000) 0.45 g
・ (A) Infrared absorber (cyanine dye A, the above formula) 0.10 g
・ Ethyl violet 0.05g
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02g
・ (B) Acrylic resin 0.1g
(Compound having the composition and weight average molecular weight shown in Table 1)
・ Methyl ethyl ketone 5g
・ Propylene glycol monomethyl ether 20g
・ Γ-Butyrolactone 5g

[Recording Layer Formation 4]
A coating solution E having the following composition is coated on a support provided with an intermediate layer with a wire bar, and then dried in a drying oven at 160 ° C. for 60 seconds so that the coating amount becomes 1.60 g / m ^2. A sex lithographic printing plate was obtained.

<Coating liquid E>
・ Novolak resin (2,3-xylenol / m-cresol / p-cresol = 1/5/4, weight average molecular weight 8000) 1.0 g
・ (A) Infrared absorber (cyanine dye A, the above formula) 0.10 g
・ Ethyl violet 0.05g
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02g
・ (B) Acrylic resin 0.1g
(Compound having the composition and weight average molecular weight shown in Table 1)
・ Methyl ethyl ketone 20g

The photosensitive lithographic printing plates of Examples 1 to 16 and Comparative Examples 1 to 4 were obtained by combining the type of support, the type of recording layer, and the added acrylic resin as shown in Table 1 by the above preparation method.
In Table 1, the comparative compound (X) is an acrylic resin having methyl methacrylate / methacrylic acid = 70/30 and a weight average molecular weight of 10,000. In Table 1, the comparative compound (Y) is an acrylic resin having ethyl acrylate / acrylic acid = 30/70 and a weight average molecular weight of 30,000.

[Evaluation of photosensitive planographic printing plate]
<Evaluation of ablation>
A transparent polyethylene terephthalate film (manufactured by Fuji Film Co., Ltd.) having a thickness of 0.1 mm was brought into close contact with the surface of the obtained photosensitive lithographic printing plate, and a drum rotation speed of 150 rpm, The entire surface was exposed with a beam intensity of 10 W. After the exposure, the polyethylene terephthalate film was removed and visually observed, and the surface contamination was observed. The case where no stain was observed was judged as ◯, the case where stain was slightly observed was judged as Δ, and the case where the stain was not visible through the film through the other side was judged as ×.

<Development evaluation>
The resulting photosensitive lithographic printing plate was imaged in a test pattern with a Trend setter manufactured by Creo at a drum rotation speed of 150 rpm and a beam intensity of 8 W. Thereafter, a PS processor LP-940H manufactured by FUJIFILM Corporation was used, and the liquid temperature was kept at 30 ° C., and development was performed for 12 seconds to obtain a sample for evaluation. At this time, as the developer, a solution obtained by blowing carbon dioxide into a solution obtained by mixing developer DT-2R manufactured by Fuji Film Co., Ltd. and tap water at a ratio of 1: 6.5 was used. Further, as the gum solution, a solution obtained by mixing and diluting gum solution FG-1 manufactured by Fuji Film Co., Ltd. and tap water at a ratio of 1: 1 was used. The conductivity of the developer was changed from 58 mS / cm to 42 mS / cm at 2 mS / cm intervals, and the obtained samples were observed. First, the color and the state of image formation were visually observed in the image area, and the highest electrical conductivity at which a good image was obtained without image blurring was indicated by a numerical value. It means that it is so favorable that a numerical value is large, and it can develop also with a developing solution with a high liquid feeling. Further, the non-image area was observed with a magnifying glass, and the electric conductivity at which a pot-like residual film began to be generated was shown numerically. This means that the smaller the numerical value, the better, and it is possible to develop with a developing solution having a low liquid feeling.

<Evaluation of sensitivity>
The obtained photosensitive lithographic printing plate was drawn on an image by changing the beam intensity at a constant drum rotation speed of 150 rpm on a Trend setter manufactured by Creo. Thereafter, a PS processor LP-940H manufactured by FUJIFILM Corporation was used, and the liquid temperature was kept at 30 ° C., and development was performed for 12 seconds to obtain a sample for evaluation. At this time, as the developer, a solution obtained by mixing a developer DT-2 manufactured by Fuji Film Co., Ltd. and tap water at a ratio of 1: 8 was used. Further, as the gum solution, a solution obtained by mixing and diluting gum solution FG-1 manufactured by Fuji Film Co., Ltd. and tap water at a ratio of 1: 1 was used. The obtained sample was observed with a magnifying glass, and the minimum beam intensity at which no pot-like residual film was generated was shown as sensitivity. A smaller value means higher sensitivity and better sensitivity.
These results are shown together in Table 1.

  From Table 1, the photosensitive lithographic printing plates of Examples 1 to 16 were compared with Comparative Examples 1 and 4 in which the acrylic resin of the present application was not added. It turns out that generation | occurrence | production is suppressed. On the other hand, the photosensitive lithographic printing plates of Comparative Examples 1 and 4 to which the acrylic resin of the present application is not added are greatly inferior in ablation. Moreover, it turns out that the photosensitive lithographic printing plate of Comparative Example 2 and Comparative Example 3 to which a known acrylic resin other than the present invention is added is inferior in developability on the high liquid side. Further, the photosensitive lithographic printing plate of Comparative Example 2 was insufficient in suppressing ablation.

Claims (2)

  A photosensitive lithographic printing plate precursor for infrared laser having a recording layer provided on a support having a hydrophilic surface, wherein the recording layer comprises (a) an infrared absorber, and (b) ethyl (meth) acrylate and A photosensitive lithographic printing plate for infrared laser, comprising: an acrylic resin containing, as polymerization components, 50 to 95 mol% of a polymerizable monomer selected from propyl (meth) acrylate and a polymerizable monomer having an acid group Original edition.   A photosensitive lithographic printing plate precursor for infrared laser, in which a recording layer having a multilayer structure formed by laminating a plurality of recording layers is provided on a support having a hydrophilic surface, the outermost recording layer among the recording layers However, (a) Infrared absorber and (b) 50 to 95 mol% of a polymerizable monomer selected from ethyl (meth) acrylate and propyl (meth) acrylate and a polymerizable monomer having an acid group are used as polymerization components. A photosensitive lithographic printing plate precursor for infrared laser, characterized by containing an acrylic resin.