JP2010066732A - Photosensitive lithographic printing plate precursor for infrared laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate precursor for infrared laser which exhibits excellent chemical and scratch resistances of an image area, has good developability, and improves printing durability when heat-treated at a high temperature after development. <P>SOLUTION: The photosensitive lithographic printing plate precursor includes in the following order: a support having a hydrophilic surface; a lower layer containing a polymer compound having a unit derived from a (meth)acrylic acid derivative monomer of a specific structure, a polymer compound having an aminomethyl structure-containing group in a side chain, and an infrared absorbent; and an upper layer containing a water-insoluble and alkali-soluble resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photosensitive lithographic printing plate precursor for infrared laser, and more specifically, so-called direct lithographic photosensitive lithographic printing capable of direct plate making by scanning infrared laser light based on a digital signal from a computer or the like. Regarding the original edition.

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.
A photosensitive lithographic printing plate precursor 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 plate comprising a binder resin and an IR dye that absorbs light and generates heat as essential components. It is a printing plate master. When the infrared laser is exposed to the infrared laser on the lithographic printing plate precursor, the IR dye or the like in the lithographic printing plate precursor for the infrared laser is added to the binder resin in the unexposed portion (image portion) when a positive photosensitive layer is provided. It acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by interacting with it. 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.

Such lithographic printing plate precursors for infrared lasers still have various problems, and one of them is how to improve resistance to various printing chemicals. If the surface has low chemical resistance, it is not preferred because the image portion may be altered or dissolved due to chemical splashing during printing or unwiping after use of the chemical, resulting in a problem that ink does not drip during printing. Another problem is how to improve the scratch resistance of the surface. If the scratch resistance is low, there is a problem that the original image portion is worn by being rubbed and damaged by a member in contact with the surface when performing exposure or development automatically, which is also not preferable.
Various studies have been made on these issues. For example, a technique for forming a recording layer having an alkali-soluble resin excellent in chemical resistance has been proposed (see, for example, Patent Document 1). However, although this recording layer shows an improvement in chemical resistance, there is a problem that the periphery of a slight scratch that has entered before development is dissolved during development, and white spots are generated in the image area.

In addition, it is considered that the structure of the resin layer of the lithographic printing plate having two or more layers is useful for achieving both chemical resistance and scratch resistance. For example, a polymer compound having a maleimide compound as a constituent unit is used in the lower layer. Although it has been proposed (see, for example, Patent Document 2), the adhesion between the lower layer and the upper layer is not always sufficient, and further improvement has been demanded.
Moreover, although patent documents 3-5 describe what improves chemical resistance and scratch resistance in burning, further improvements have been demanded.
JP 2005-62875 A US Patent Application Publication No. 2004/0067432 US Pat. No. 7,144,661 US Pat. No. 7300726 International Publication No. 07/084284 Pamphlet

  The object of the present invention is excellent in chemical resistance and scratch resistance of the image area, and also has good developability, and further, when subjected to heat treatment at a high temperature after development, the photosensitivity for infrared laser is remarkably improved in printing durability. It is to provide a sex lithographic printing plate precursor.

As a result of diligent research, the present inventor achieves the above-mentioned problems by the following photosensitive lithographic printing plate precursor for infrared laser (hereinafter also simply referred to as “lithographic printing plate precursor” or “photosensitive lithographic printing plate”). I found.
That is, the present invention
A polymer having at least a unit derived from a polymerizable monomer represented by the following general formula (I) on a support having a hydrophilic surface, and a polymer having a group represented by the following general formula (II) in the side chain A photosensitive lithographic printing plate precursor for infrared laser, comprising a lower layer containing a compound and an infrared absorber and an upper layer containing a water-insoluble and alkali-soluble resin in this order.

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a methylene or ethylene, R ³ represents a hydrogen atom or a methyl group, and X represents O or NH.

In the formula, Z ¹ , Z ² , and Z ³ each independently represent a monovalent substituent composed of a hydrogen atom or a nonmetallic atom.

Here, "having in order" means having at least the lower layer and the upper layer in this order on a support having a hydrophilic surface, and other layers provided as desired, for example, an undercoat layer, The existence of a protective layer, a backcoat layer, etc. is not denied.
The lithographic printing plate precursor according to the present invention is excellent in chemical resistance and scratch resistance of the image area by containing two kinds of specific polymer compounds in the lower layer. Printability can be improved. The reason for this is not clear, but is considered as follows. That is, the chemical resistance of the entire printing plate is improved by using two kinds of polymer compounds having excellent chemical resistance in the lower layer. Further, by having a multi-layer structure, it is possible to control the scratch resistance in the upper layer. Furthermore, the polymer compound used in the lower layer can undergo a crosslinking reaction by heat, and when it is heat-treated at a high temperature after development, it is considered that the printing durability can be remarkably improved.

  According to the present invention, not only is the chemical resistance and scratch resistance of the image area excellent, but also the developability is good, it is possible to obtain a good printed matter. A photosensitive lithographic printing plate precursor for infrared laser with improved printability can be provided.

The photosensitive lithographic printing plate precursor for infrared laser of the present invention comprises, on a support having a hydrophilic surface, a polymer compound having at least a polymerizable monomer unit represented by the general formula (I) and the general formula (II). ), And a lower layer containing a polymer compound having a group shown in the side chain, and an upper layer containing a polymer compound different from the aforementioned polymer compound in this order. It is a sex lithographic printing plate precursor.
Below, each item is demonstrated one by one.

Units derived from the polymerizable monomer represented by the general formula (I) (hereinafter also referred to as “polymerizable monomer (I)” or “compound (I)”) contained in the lower layer of the lithographic printing plate precursor according to the invention. A polymer compound having at least the above (hereinafter also referred to as “polymer compound (I)”) will be described.
In the general formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents a methylene or ethylene, R ³ represents a hydrogen atom or a methyl group, and X represents O or NH.
R ¹ is preferably a hydrogen atom, R ² is preferably methylene. When X is O, R ³ is preferably a methyl group.
Specific examples of the polymerizable monomer (I) are not particularly limited, but N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-methoxyethylacrylamide, N-methoxyethylmethacrylamide, methoxymethyl acrylate, methoxymethyl methacrylate N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxyethylmethacrylamide and the like.

The polymer compound (I) may be a polymer composed only of the polymerizable monomer (I), or may be a copolymer with other copolymerizable monomers. A copolymer of the polymerizable monomer (I) and another copolymerizable monomer is preferable from the viewpoint that desired characteristics can be appropriately provided.
Moreover, as another copolymerizable monomer, a monomer having an acid group is preferable.

  Although it does not specifically limit as a monomer which has an acid group, For example, the monomer which has an acidic group mentioned to the following (1)-(6) can be mentioned.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) sulfonic acid group _(-SO 3 H)
(6) 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 monomer which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.

(1) Examples of the monomer having a phenol group include acrylamide, methacrylamide, acrylic ester or methacrylic ester having a phenol group, and hydroxystyrene.

(2) Examples of the monomer having a sulfonamide group include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. . Among these, low molecular weight compounds 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 are preferable. For example, the following formulas (i) to (v ).

(In the formula, X ¹ and X ² each independently represent —O— or —NR ^7. R ¹ and R ⁴ each independently represents a hydrogen atom or —CH _3. R ² , R ⁵ , R ⁹ , R ¹² and R ¹⁶ each independently represents an alkylene group, a cycloalkylene group, an arylene group or an aralkylene group having 1 to 12 carbon atoms, and R ³ , R ⁷ and R ¹³ each independently represent Represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, and R ⁶ and R ¹⁷ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or an aryl group. R ⁸ , R ¹⁰ and R ¹⁴ each independently represents a hydrogen atom or —CH ₃ , R ¹¹ and R ¹⁵ each independently represents a single bond or an alkylene having 1 to 12 carbon atoms. Group, cycloalkylene group, arylene group or aralkylene group Y ¹ and Y ² each independently represents a single bond or CO. The above alkylene group, cycloalkylene group, arylene group, aralkylene group, alkyl group, cycloalkyl The group, aryl group, or aralkyl group may have a substituent, and a preferred substituent is an alkyl group.)

  Among the compounds represented by formulas (i) to (v), in the 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) Examples of the monomer having an active imide group include compounds having one or more active imide groups represented by the following structural formula and one or more polymerizable unsaturated groups in the molecule.

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

(4) Examples of the monomer having a carboxylic acid group include compounds having one or more carboxylic acid groups and polymerizable unsaturated groups in the molecule. In the lithographic printing plate precursor according to the invention, in particular, acrylic acid, methacrylic acid, maleic acid and itaconic acid can be preferably used.

(5) Examples of the monomer having a sulfonic acid group include compounds having one or more sulfonic acid groups and polymerizable unsaturated groups in the molecule.
(6) Examples of the monomer having a phosphoric acid group include compounds having at least one phosphoric acid group and a polymerizable unsaturated group in the molecule.

  In the lithographic printing plate precursor according to the invention, a monomer having a carboxylic acid group is preferred, and methacrylic acid is particularly preferred.

  In addition to the polymerizable monomer (I) and the monomer having an acid group, the polymer compound (I) may be obtained by further copolymerizing an arbitrary polymerizable monomer. The other monomer is not particularly specified as long as it is a monomer copolymerizable with the monomer component of the polymer compound (I), but (meth) acrylic acid ester, (meth) acrylonitrile, styrenic compound, maleimides, etc. Can be mentioned.

The amount of the component derived from the polymerizable monomer (I) in the polymer compound (I) is not particularly limited, but is preferably 5 to 95 mol%, more preferably 10 to 90 mol%, and polymerization having an acid group. The amount of the component derived from the polymerizable monomer is also not particularly limited, but is preferably 1 to 90 mol%, more preferably 10 to 70 mol%, and is not particularly limited when there are components derived from other copolymerization monomers. However, it is preferably 1 to 70 mol%.
The method for synthesizing the polymer compound (I) is not particularly limited, and widely known radical polymerization methods can be used.
Further, the molecular weight of the polymer compound (I) is not particularly limited, but is preferably 5000 to 500,000, more preferably 8000 to 300,000 in terms of weight average molecular weight.

Examples of preferred copolymers are shown below.
(1) N-methoxymethylmethacrylamide / methacrylic acid / acrylonitrile = 40/30/30 (molar ratio), copolymer having a weight average molecular weight of 60,000
(2) N-methoxymethylmethacrylamide / methacrylic acid / benzyl methacrylate = 50/25/25 (molar ratio), copolymer having a weight average molecular weight of 70,000
(3) N-methoxyethylmethacrylamide / methacrylic acid / N-phenylmaleimide = 65/20/15 (molar ratio), copolymer having a weight average molecular weight of 40,000
(4) N-methoxyethylmethacrylamide / 4-hydroxyphenylmethacrylamide / acrylonitrile = 30/25/45 (molar ratio), copolymer having a weight average molecular weight of 50,000
(5) Copolymer of methoxymethyl methacrylate / methacrylic acid / p-hydroxystyrene / acrylonitrile = 40/20/5/35 (molar ratio), weight average molecular weight 70,000
(6) Copolymer having methoxymethyl methacrylate / methacrylic acid / N-phenylmaleimide / acrylonitrile = 25/25/10/40 (molar ratio) and weight average molecular weight 70,000
(7) N-hydroxymethylmethacrylamide / methacrylic acid / benzyl methacrylate = 30/30/40 (molar ratio), copolymer having a weight average molecular weight of 70,000
(8) N-hydroxymethylmethacrylamide / methacrylic acid / N-phenylmaleimide = 65/25/10 (molar ratio), copolymer having a weight average molecular weight of 70,000

  The addition amount of the polymer compound (I) in the lower layer is not particularly limited, but is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, and particularly preferably 10 to 10% by mass with respect to the total amount of solid components in the lower layer. Used in an amount of 70% by mass. It is preferable that the addition amount of the polymer compound (I) is within the above range because the chemical resistance is excellent and the thermal crosslinking efficiency is increased.

Next, a polymer compound having a group represented by the general formula (II) in the side chain contained in the lower layer of the lithographic printing plate precursor according to the invention (hereinafter also referred to as “polymer compound (II)”) will be described. To do.
In the general formula (II), Z ¹ , Z ² , and Z ³ each independently represent a monovalent substituent consisting of a hydrogen atom or a nonmetallic atom.
The monovalent substituent composed of a nonmetallic atom represented by Z ¹ , Z ² , or Z ³ is preferably a substituent composed of a linking site and a terminal site. In addition, a connection site | part is used as needed, and the monovalent | monohydric substituent which consists of a nonmetallic atom may be formed only from the terminal site | part mentioned below.
In addition, the monovalent substituent composed of a nonmetallic atom may be further substituted with an alkyl group, an aryl group, or the like.

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

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

  The hydrophobic aminoalkyl group as shown above is preferably bonded to the side chain of the alkali-soluble resin, and as the alkali-soluble resin, a conventionally known alkali-soluble resin can be used. It is preferably bonded to the side chain of the alkali-soluble resin having a phenol structure, and specifically, it is preferably covalently bonded to the phenyl ring of the phenol resin.

Hereinafter, preferred structures of the polymer compound (II) having a group represented by the general formula (II) in the side chain contained in the lower layer of the lithographic printing plate precursor according to the invention are shown, but the invention is not limited thereto. It is not something.
In addition, the general formula (2) shown below shows a preferable structure of the polymer compound (II), and examples of the substituents R, Z ¹ , Z ² and Z ^{3 in} the general formula (2) Are shown in Tables 1 to 3 below. In addition, the substituents R, Z ¹ , Z ² and Z ³ shown in the following Tables 1 to 3 can be arbitrarily combined.

  Specific examples (compound numbers 1 to 5) of the polymer compound (II) represented by the general formula (2) are listed in the following table, but the present invention is not limited thereto.

In addition, if the polymer compound (II) has a structure represented by the general formula (2), phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2 , 4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol can be included as a repeating unit.
Further, the content of the repeating unit having a group represented by the general formula (II) in the polymer compound (II) is not particularly limited, but is preferably 30 to 100 mol%, more preferably 50 to 100 mol. %.

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

  The molecular weight of the polymer compound (II) is preferably 2000 or more, more preferably 3000 to 500,000 in terms of weight average molecular weight. Moreover, in number average molecular weight, 1000 or more are preferable and 2000-400,000 are more preferable.

  The addition amount of the polymer compound (II) in the lower layer is not particularly limited, but is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, and particularly preferably 10 to 10% by mass with respect to the total amount of solid components in the lower layer. Used in an amount of 70% by mass. It is preferable that the addition amount of the polymer compound (II) is within the above range because the chemical resistance is excellent and the thermal crosslinking efficiency is increased.

  Further, the content ratio of the polymer compound (I) and the polymer compound (II) contained in the lower layer of the lithographic printing plate precursor according to the invention is not particularly limited, and preferably I / II = 95/5 to 5 / 95, and more preferably 90/10 to 10/90.

(Infrared absorber)
The lower layer of the lithographic printing plate precursor according to the invention contains an infrared absorber in addition to the polymer compound (I) and the polymer compound (II).
The infrared absorber used here is not particularly limited as long as it is a dye having an absorption maximum from a wavelength of 750 nm to 1,400 nm and absorbing light of this wavelength and generating heat, and is known as an infrared absorbing dye. Various dyes can be used.

  As the infrared absorbing agent in the present invention, commercially available dyes and known ones described in literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb infrared light or near infrared light are particularly preferred because they are suitable for use in lasers that emit infrared light or near infrared light.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Furthermore, cyanine dyes are particularly preferred. Specific examples of cyanine dyes that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969.

  It is preferable that an infrared absorber is contained in 0.01-50 mass% in the total solid of a lower layer, More preferably, it is 0.1-30 mass%, Most preferably, it is 1.0-30 mass%. There is a ratio.

(Other polymer compounds)
In the lower layer in the present invention, in addition to the specific polymer compound described above, other polymer compounds can be used in combination. The polymer compound used in combination may be one type or two or more types. Moreover, although a high molecular compound is used for the upper layer, two or more types of high molecular compounds may be used. Here, these polymer compounds are described.

  Other polymer compounds that can be used in the present invention are preferably polymer compounds that are soluble or swellable in an alkaline aqueous solution. Such a high molecular compound is a high molecular compound different from the specific high molecular compound, and has an acidic group listed in (1) to (6) below in the main chain and / or side chain of the polymer. Mention may be made of molecular compounds.

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

In the acidic groups listed as (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R ^A is a hydrocarbon group which may have a substituent. Represents.

  Examples of the polymer compound having an acidic group selected from (1) to (6) include the following.

  (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 such compounds 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. Sulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be suitably 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 having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule, respectively. 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. Acrylic acid, methacrylic acid, maleic acid, and itaconic acid can be particularly preferably used in the multilayer sensitive material type printing plate precursor of the present invention.
(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 a urea bond as a linking group can also be used.

  Among the polymer compounds having an acidic group selected from (1) to (6), a polymer having (1) a phenol group, (2) a sulfonamide group, (3) an active imide group, and (4) a carboxylic acid group. A compound is 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 (1) to (6) is not particularly limited to one kind, and two or more minimum structural units having the same acidic group are used, or different acidic groups are used. What copolymerized 2 or more types of the minimum structural unit which has can also be used.

  In the case where the polymer compound is a copolymer, it is preferable that a compound having an acidic group selected from (1) to (6) to be copolymerized is contained in an amount of 3 mol% or more in the copolymer. % Is more preferable.

As described above, among the other polymer compounds mentioned as examples, the other polymer compound used in combination with the specific polymer compound in the lower layer is preferably a copolymer having a sulfonamide group and / or a carboxylic acid group. Examples of the copolymer component include alkyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile, and N-phenylmaleimide.
Two or more kinds of other polymer compounds may be used in combination.

  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 is 500 to 20,000, and the number average molecular weight is 200 to 10,000. Those are preferred. When the other polymer compound is other polymer compound, the weight average molecular weight 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 It is preferably 300,000, a number average molecular weight of 800 to 250,000 and a dispersity (weight average molecular weight / number average molecular weight) of 1.1 to 10.

  In the present invention, the total content of the polymer compound (specific polymer compound and other polymer compounds) contained in the lower layer is 30 to 99% by mass, preferably from the viewpoint of durability and sensitivity of the recording layer. It is 50-99 mass%, Most preferably, it is the range of 65-99 mass%.

(Other ingredients)
Various additives can be further added to the lower layer as necessary.
For example, in order to adjust the solubility of the lower layer, it is preferable to add a dissolution inhibitor such as onium salt, aromatic sulfone compound, aromatic sulfonic acid ester compound, polyfunctional amine compound, etc. -The use of a substance that is thermally decomposable, such as a quinonediazide compound and a sulfonic acid alkyl ester, and that substantially reduces the solubility of the alkali-soluble resin in a state where it does not decompose can prevent the dissolution of the image area in the developer. It is preferable in that it can be controlled. As the onium salt, a diazonium salt and a quaternary ammonium salt are particularly preferable.

  In addition, a dissolution inhibitor having no decomposability may be used in combination, such as sulfonic acid ester, phosphoric acid ester, aromatic carboxylic acid ester, aromatic disulfone, carboxylic acid anhydride, aromatic ketone, aromatic aldehyde, aromatic Examples thereof include amines and aromatic ethers.

  Furthermore, for the purpose of improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in the lower layer together with surfactants, image colorants, and a visible image immediately after heating by exposure. Bakeout agents and plasticizers can also be used.

Formation of a lower layer can be formed by dissolving each component which forms a lower layer in a solvent, and apply | coating on a suitable support body. Solvents that can be used include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, Examples include, but are not limited to, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. Is not to be done. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.

Coating a lower layer coating solution on the support, the solid coating amount of the lower layer obtained after drying is preferably ^{0.3g / m 2 ~5.0g / m 2} , more preferably 0.5 g / m ² It is the range of -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.

  Various methods can be used as a method of applying the lower layer coating solution on the support, such as bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, Examples thereof include roll coating.

[Upper layer containing water-insoluble and alkali-soluble resin]
The upper layer in the present invention is characterized by containing a water-insoluble and alkali-soluble resin (hereinafter, appropriately referred to as “alkali-soluble resin”). Hereafter, each component which the upper layer in this invention contains is demonstrated.

(Water-insoluble and alkali-soluble resin)
The alkali-soluble resin that can be used for the upper layer is not particularly limited as long as it is insoluble in water and has a property of dissolving when contacted with an alkaline developer, but the main chain and / or side chain in the polymer is acidic. A homopolymer obtained from a monomer containing a group, a copolymer thereof, or a mixture thereof is preferable.

  As such an alkali-soluble resin having an acidic group, in particular, a polymer compound having a functional group in any one of (1) a phenolic hydroxyl group, (2) a sulfonamide group, and (3) an active imide group. Can be mentioned. For example, although the following are illustrated, this invention is not limited to these.

  (1) Examples of the polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p Any of-or m- / p-mixing may be used. Examples include novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. In addition to this, a polymer compound having a phenolic hydroxyl group in the side chain is preferably used as the polymer compound having a phenolic hydroxyl group. As a polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer comprising a low molecular compound having at least one phenolic hydroxyl group and at least one polymerizable unsaturated bond is homopolymerized, or other polymerization is performed on the monomer. And a high molecular compound obtained by copolymerizing a functional monomer.

  Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic ester, methacrylic ester, and hydroxystyrene having a phenolic hydroxyl group. Specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N- (3- Hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p-hydroxy Phenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) Preferable are til acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, etc. Can be used. Such resins having a phenolic hydroxyl group may be used in combination of two or more. Furthermore, as described in U.S. Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin, These copolymers may be used in combination.

(2) Examples of the alkali-soluble resin having a sulfonamide group include polymer compounds obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the monomer with another polymerizable monomer. The polymerizable monomer having a sulfonamide group includes one or more sulfonamide groups —NH—SO ₂ — in which at least one hydrogen atom is bonded on a nitrogen atom and one or more polymerizable unsaturated bonds in one molecule. And a polymerizable monomer comprising a low molecular weight compound. Among these, 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 is preferable.

(3) The alkali-soluble resin having an active imide group is preferably one having an active imide group in the molecule, and the polymer compound has one unsaturated bond polymerizable with the active imide group in each molecule. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer comprising the above-described low molecular weight compound, or copolymerizing the monomer with another polymerizable monomer.
As such a compound, specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

  The alkali-soluble resin contained in the upper layer is a polymer compound obtained by polymerizing two or more of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, and a polymerizable monomer having an active imide group. Preferably there is. Although there is no restriction | limiting in the copolymerization ratio of the said polymerizable monomer, and the combination of a polymerizable monomer, Especially the polymerizable monomer which has a sulfonamide group in the polymerizable monomer which has a phenolic hydroxyl group, and / or the polymerizable property which has an active imide group When monomers are copolymerized, the compounding polymerization ratio of these components is preferably in the range of 50:50 to 5:95, and particularly preferably in the range of 40:60 to 10:90.

  Furthermore, as the alkali-soluble resin contained in the upper layer, one or more kinds selected from a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group are used. In addition to the polymerizable monomer, a polymer compound obtained by copolymerizing another polymerizable monomer is preferable. As a copolymerization ratio in this case, it is preferable that the monomer which provides alkali solubility is contained 10 mol% or more, and what contains 20 mol% or more is more preferable. If the copolymerization component of the monomer imparting alkali solubility is 10 mol% or more, alkali solubility is likely to be sufficient, and the development latitude tends to be improved, which is preferable.

  When the alkali-soluble resin contained in the upper layer is a homopolymer or copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group, the weight average molecular weight Are preferably 2,000 or more and a number average molecular weight of 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

  In particular, when the alkali-soluble resin contained in the upper layer is a phenol formaldehyde resin or a cresol aldehyde resin, the weight average molecular weight is 500 to 20,000, and the number average molecular weight is 200 to 10,000. Is preferred.

As the alkali-soluble resin contained in the upper layer, a resin having a phenolic hydroxyl group is desirable in terms of causing strong hydrogen bonding in the unexposed area and easily releasing some hydrogen bonds in the exposed area. Among the resins having a functional hydroxyl group, a novolak resin is particularly preferable.
In the present invention, two or more kinds of alkali-soluble resins having different dissolution rates in an alkaline aqueous solution may be mixed and used, and the mixing ratio in that case is arbitrary. The alkali-soluble resin suitable for mixing with the resin having a phenolic hydroxyl group is preferably an acrylic resin because of its low compatibility with a resin having a phenolic hydroxyl group, and more preferably a sulfoamide group. It is an acrylic resin.

  The content of the alkali-soluble resin in the total solid content of the upper layer is preferably in the range of 50 to 98% by mass from the viewpoint of the sensitivity and durability of the recording layer. In addition, this content points out the total amount, when using together multiple types of alkali-soluble resin.

  An infrared absorber can be added to the upper layer. The infrared absorber is not particularly limited as long as it has an absorption maximum from a wavelength of 750 nm to 1,400 nm and absorbs light of this wavelength and generates heat, and various dyes known as infrared absorbing dyes can be used. Specifically, the same materials as those mentioned as the infrared absorber used in the lower layer can be used.

  As content of the infrared absorber in an upper layer, it is preferable that it is 0.01-50 mass% in the total solid of an upper layer, More preferably, it is 0.1-30 mass%, Most preferably, it is 1.0-30. It is the range of mass%. By setting it in the above range, the sensitivity becomes better, and the uniformity and durability of the upper layer (upper recording layer) become better.

  The upper layer preferably contains a development inhibitor for the purpose of increasing its inhibition (dissolution inhibiting ability).

  As a development inhibitor, it forms an interaction with the alkali-soluble resin contained in the upper layer, substantially lowers the solubility of the alkali-soluble resin in the developer in the unexposed area, and in the exposed area There is no particular limitation as long as the interaction is weakened and can be soluble in the developer, but quaternary ammonium salts, polyethylene glycol compounds and the like are particularly preferably used. In addition, when the compound which has a function of a development inhibitor is used as an infrared absorber, it is not necessary to add a development inhibitor.

  Examples of quaternary ammonium salts include tetraalkylammonium salts, trialkylarylammonium salts, dialkyldiarylammonium salts, alkyltriarylammonium salts, tetraarylammonium salts, cyclic ammonium salts, and bicyclic ammonium salts. Polyethylene glycol compounds include polyethylene glycols, polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers, polyethylene glycol alkyl aryl ethers, polypropylene glycol alkyl. Aryl ethers, polyethylene glycol glycerol esters, polypropylene glycol glycerol esters, polyethylene sorbitol esters, polypropylene glycol sorbitol esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, polyethylene glycolated ethylenediamine , Polypropylene glycolated ethylenediamines, polyethylene glycolated diethylenetriamine, and polypropylene glycol diethylenetriamines.

  In addition, substances that are thermally decomposable, such as onium salts, o-quinonediazide compounds, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, and that substantially reduce the solubility of alkali-soluble resins when not decomposed. Is preferably used from the viewpoint of improving the inhibition of the image portion in the developer.

  Examples of onium salts that can be used in the present invention include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like, and among these, diazonium salts are particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.

Suitable quinonediazides include o-quinonediazide compounds.
The amount of these added is preferably in the range of 0.1 to 10% by mass, and more preferably in the range of 0.5 to 5% by mass in the total solid content of the upper layer.

  In forming the upper layer, in addition to the above-described components, various additives can be added as long as the effects of the present invention are not impaired.

  For example, acid anhydrides, phenols, and organic acids may be added for the purpose of improving sensitivity, and nonionic surfactants and amphoteric surfactants are used to improve coatability and improve processing stability against development conditions. Agents, siloxane compounds, and fluorine-containing monomer copolymers can be added. Baking agents for obtaining a visible image immediately after heating by exposure and dyes and pigments as image colorants can be added. Further, a plasticizer may be added to impart flexibility and the like of the coating film.

  The upper layer can usually be formed by dissolving the above components in a solvent and coating, but preferably the one that does not dissolve the lower layer as much as possible. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Mention may be made of ethane, methyl lactate, ethyl lactate, toluene and the like. These solvents are used alone or in combination.

Further, the solid coating amount of the upper layer obtained after applying and drying the upper layer coating solution on the lower layer is preferably in the range of 0.05 to 2.0 g / m ² , more preferably 0.8. in the range of 1~1.0g / m ^2.

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

  As a support that can be applied to a lithographic printing plate precursor, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film 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.

  The composition of the aluminum plate applicable to the present invention is not specified, and an aluminum plate made of a publicly known material can be used as appropriate. 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. If the amount of the anodized film is 1.0 g / m ² or more, the printing durability is sufficient, and the non-image part of the lithographic printing plate is hardly scratched, so that the ink adheres to the scratched part during printing. “Scratches and dirt” do not occur, which is preferable.

  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.

The lithographic printing plate precursor according to the present invention is provided with a recording layer having a multi-layer structure including the upper layer and the lower layer as described above on the support, and if necessary, between the support and the lower layer, Further, an undercoat layer can be provided. 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. Various organic compounds are used as the primer layer component, such as carboxymethylcellulose, dextrin, gum arabic, phosphonic acids having amino groups, organic phosphonic acids, organic phosphoric acids such as phenylphosphoric acid, organic phosphinic acids, amino acids And a hydrochloride of an amine having a hydroxy group, and a polymer compound having a component having an acid group and a component having an onium group described in JP-A No. 2000-241962. The coverage of the undercoat layer is in terms of printing durability, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2.

-Prepress processing of lithographic printing plate precursors-
〔exposure〕
The lithographic printing plate precursor according to the invention is image-formed by heat. Specifically, an image is formed by scanning exposure using a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared light having a wavelength of 700 to 1200 nm. The planographic printing plate precursor of the present invention can also form an image by direct image-like recording using a thermal recording head or the like, high-illuminance flash exposure such as a xenon discharge lamp, or infrared lamp exposure.

The output of the infrared laser 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 .

〔developing〕
The exposed lithographic printing plate precursor 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, trisodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof 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. An aqueous solution having a pH of 12 or more called “silicate developer”, and another more preferable developer does not contain an alkali silicate but contains a non-reducing sugar (an organic compound having a buffering action) and a base. Non-silicate developer ".

  Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. . 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 lithographic printing plate precursor developed using a developer and a replenisher is post-treated with a desensitizing solution containing rinsing water containing a washing water, a surfactant and the like, gum arabic and starch derivatives. As post-processing, these processes 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 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 of the lithographic printing plate precursor according to the invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. A developing solution is sprayed from a spray nozzle. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll 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.

  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.

  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.
[Example 1]
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.
The above aluminum plate was sprayed with an aqueous NaOH solution (concentration 26 mass%, aluminum ion concentration 6.5 mass%) at a temperature of 70 ° C. to dissolve the aluminum plate 6 g / m ² . Thereafter, washing with water was performed using well water.
Next, desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid having a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying.

An electrochemical surface roughening treatment was continuously performed 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 450 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.

The aqueous solution having a caustic soda concentration of 26 wt%, performed an aluminum ion concentration of 6.5 wt% to etching treatment by spraying at 32 ° C., the aluminum plate 0.10 g / m ² was dissolved, electrochemical by using the alternating current in the previous stage The smut component mainly composed of aluminum hydroxide generated during the 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.
A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.
Subsequently, anodizing treatment was performed. The electrolytic solution had a sulfuric acid concentration of 170 g / liter (containing 0.5% by mass of aluminum ions) and a temperature of 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .
Further, an anodized aluminum plate was immersed for 5 seconds in a solution obtained by heating a 0.5% polyvinylphosphonic acid aqueous solution to 60 ° C., and washed with water by spraying.
Thus, a support for a photosensitive lithographic printing plate was obtained.

The lower layer coating liquid A having the following composition was applied to the support obtained above with a wire bar, and then dried for 50 seconds in a drying oven set at 140 ° C. to obtain a lower layer. The coating amount after drying was 1.2 g / m ² .

<Coating liquid A for lower layer>
Copolymer of general formula (I) [polymer compound (I)] Example (1) Amount described in Table 5 “Compound No. 1 (compound 1)” [polymer compound (II)]
(Weight-average molecular weight 8,000) Cyanine dye P 0.15 g in the amount shown in Table 5 and the following structure

・ Ethyl violet 0.05g
・ Methyl ethyl ketone 5.00g
・ 1-methoxy-2-propanol 5.00g
・ N, N-dimethylformamide 10.00g

On the lower layer thus obtained, an upper layer coating solution A having the following composition was coated with a wire bar, and then dried in a drying oven set at 130 ° C. for 60 seconds to obtain an upper layer. The coating amount after drying was 0.4 g / m ² .

<Upper layer coating liquid A>
-Novolak resin (weight average molecular weight 5,000) of m-cresol / p-cresol = 60/40 0.90 g
・ Cyanine dye P of the above structure 0.10g
・ Methyl ethyl ketone 10.00g
1-methoxy-2-propanol 10.00g

  In this way, a photosensitive lithographic printing plate (a) was obtained.

[Example 2] to [Example 10]
In Example 1, the lower layer copolymer (1) [Polymer Compound (I)], “Compound No. 1 Compound (Compound 1)” [Polymer Compound (II)], and the compounds shown in Table 5 Photosensitive lithographic printing plates (b) to (j) were obtained in the same manner as in Example 1 except that the addition amount (Compound Nos. 1 to 5, all weight average molecular weights 8,000) was changed.

[Comparative Example 1]
In Example 1, copolymer of lower layer (1) Instead of [polymer compound (I)], N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) as a polymer compound A photosensitive lithographic printing plate (k) was obtained in the same manner as in Example 1 except that 0.6 g of the copolymer (weight average molecular weight 20,000) was used.
[Comparative Example 2]
In Example 1, 0.2 g of novolak resin (weight average molecular weight 5,000) of m-cresol / p-cresol = 60/40 was used instead of the lower layer compound 1 [polymer compound (II)]. Was the same as in Example 1 to obtain a photosensitive lithographic printing plate (l).
[Comparative Example 3]
A photosensitive lithographic printing plate (m) was obtained in the same manner as in Example 1 except that no upper layer was provided in Example 1.

[Evaluation of chemical resistance]
The resulting photosensitive lithographic printing plates (a) to (m) were subjected to a 175 lpi / 2400 dpi halftone dot on a Luxel PLANETTER T-9800HS manufactured by Fuji Film Co., Ltd. under conditions of a beam output of 100% and a drum rotation speed of 150 rpm. Drawing (exposure) was performed on an image of a test pattern containing a chart with an area ratio of 1 to 99%.
Next, a lithographic printing plate was obtained by performing development processing and gumming treatment using an Autolith PN85CE automatic developing machine manufactured by AGFA with a developer temperature of 30 degrees and a development time of 25 seconds. At this time, a developer EP26 manufactured by AGFA was used as the developer, and FG-1 manufactured by Fuji Film Co., Ltd. was diluted 1: 1 with water as the gum solution. The lithographic printing plates thus obtained were all well developed and it was confirmed that there was no difference in developability.

Next, printing was performed using the lithographic printing plate thus obtained. At this time, the Lislon printer manufactured by Komori Corporation was used as the printing machine, the Varius G black ink manufactured by Dainippon Ink and Chemicals was used as the ink, and Fuji Film Co., Ltd. was used as the fountain solution. Each of IF-102 diluted with water to a concentration of 4% was used, and each time 5000 sheets were printed, the plate surface was wiped with a multi-cleaner manufactured by Fuji Film Co., Ltd. Printing durability was evaluated based on the number of printed sheets when printed on high-quality paper and visually recognized that the density of the solid image started to decrease. A larger value means better chemical resistance. The results are shown in Table 5.
As shown in Table 5, the photosensitive lithographic printing plates (a) to (j) satisfying the requirements of the constitution of the present invention all showed good chemical resistance. On the other hand, the photosensitive lithographic printing plates (k) and (l) were inferior in chemical resistance.

[Evaluation of scratch resistance]
The obtained photosensitive lithographic printing plates (a) to (m) were rubbed 15 times with Abrazer felt CS5 to which a load of 250 g weight was applied using a rotary ablation tester manufactured by TOYOSEIKI.
Next, this plate was developed by the same method as the evaluation of chemical resistance described above. For the plate thus obtained, the density of the plate surface was measured with a Macbeth densitometer on the part subjected to friction and the part not subjected to friction, and the absolute value of the difference was calculated. The results are shown in Table 5. The larger the value, the greater the damage to the plate due to friction.
As shown in Table 5, the photosensitive lithographic printing plates (a) to (j) satisfying the requirements of the present invention have a small value and good scratch resistance. On the other hand, both the photosensitive lithographic printing plates (k) and (l) were inferior in scratch resistance, and the photosensitive lithographic printing plate (m) was inferior in scratch resistance.

[Burning Evaluation]
The obtained photosensitive lithographic printing plates (a) to (m) were exposed and developed in the same manner as in the evaluation of chemical resistance to obtain lithographic printing plates.
Next, this plate was washed with water and the gum solution was dropped. Then, BC-3 manufactured by Fuji Film Co., Ltd. was included in the sponge as a surface-adjusting solution and dried naturally. Thereafter, it was heated at 260 ° C. for 5 minutes in a burning oven manufactured by Wisconsin. After cooling to room temperature and washing with water and dropping the surface-adjusting solution, gumming was performed using a gum coater G-800 manufactured by FUJIFILM Corporation. As a gum, a solution obtained by diluting GU-7 manufactured by Fuji Film Co., Ltd. 1: 1 with water was used.
The plate subjected to the burning treatment in this manner was printed in the same manner as the chemical resistance evaluation, and the printing durability was evaluated. The results are shown in Table 5.

As shown in Table 5, the photosensitive lithographic printing plates (a) to (j) satisfying the requirements of the present invention all exhibited good printing durability. On the other hand, the photosensitive lithographic printing plates (k) to (m) did not have printing durability as high as (a) to (j).
As shown in the above examples, the constitution of the present invention can provide a photosensitive lithographic printing plate that is excellent in both chemical resistance and scratch resistance and can obtain higher printing durability by burning.

Claims (1)

A polymer having at least a unit derived from a polymerizable monomer represented by the following general formula (I) on a support having a hydrophilic surface, and a polymer having a group represented by the following general formula (II) in the side chain A photosensitive lithographic printing plate precursor for infrared laser, comprising a lower layer containing a compound and an infrared absorber and an upper layer containing a water-insoluble and alkali-soluble resin in this order.

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a methylene or ethylene, R ³ represents a hydrogen atom or a methyl group, and X represents O or NH.

In the formula, Z ¹ , Z ² , and Z ³ each independently represent a monovalent substituent composed of a hydrogen atom or a nonmetallic atom.