JP2005084526A - Lithographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive lithographic printing original plate for IR laser light for direct platemaking having excellent development latitude and high printing durability. <P>SOLUTION: The lithographic printing original plate has two or more layers of positive recording layers on a support, the layers containing a water-insoluble and alkali-soluble resin and having the solubility in an alkaline aqueous solution increased by IR laser exposure. One of the layers contains an IR absorbent. The water-insoluble and alkali-soluble resin in the lowermost layer of the recording layers is a blend of two kinds of resin materials: resin having ≥110°C Tg and resin having ≤90°C Tg. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a positive lithographic printing plate precursor for infrared laser for so-called direct plate making which can be directly made from digital data such as a computer.

  In recent years, the development of lasers has been remarkable, and in particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can easily obtain high-power and small-sized ones. These lasers are very useful as an exposure light source when directly making a plate from digital data of a computer or the like.

As a lithographic printing plate precursor for direct plate making using a near infrared to infrared laser as a light source, an alkaline aqueous solution-soluble binder resin and an infrared absorbing dye (IR dye) that absorbs light and generates heat There is known a positive lithographic printing plate precursor for infrared lasers having a recording layer containing as an essential component.
In the unexposed state, this positive recording layer acts as a dissolution inhibitor that causes IR dyes or the like to interact with the binder resin to substantially reduce the solubility of the binder resin, and the above interaction is weakened by the heat generated upon exposure. , The solubility in an alkaline developer increases. Therefore, by alkali development after exposure, the non-exposed portion remains undissolved and becomes an image portion, and the exposed portion is dissolved and removed to become a non-image portion where the hydrophilic support surface is exposed, so that a lithographic printing plate is formed. .

  However, such positive lithographic printing plate materials for infrared lasers are more resistant to dissolution of the recording layer non-exposed portion with respect to the developer than conventional positive lithographic printing plate materials (PS plates) that are made by UV exposure. The difference between the solubility of the exposed portion and the exposed portion is still not sufficient, and there is a problem that overdevelopment and development failure are liable to occur due to fluctuations in use conditions. In addition, even if the surface condition slightly changes due to contact with the surface during handling, the unexposed area dissolves into a scratch mark during development, causing deterioration in printing durability and poor inking properties. It was. Further, the image area is deteriorated by a cleaner, ink or the like during printing, and the printing durability is insufficient.

Such a problem originates in the essential difference of the platemaking mechanism of the positive lithographic printing plate material for infrared lasers and PS plate. That is, in the recording layer (photosensitive layer) of the PS plate, an alkaline aqueous solution-soluble binder resin and an onium salt or a quinonediazide compound are essential components. The onium salt and the quinonediazide compound are separated from the binder resin in an unexposed area. In addition to functioning as a dissolution inhibitor due to the above interaction, in the exposed portion, it plays two roles of being decomposed by light to generate an acid and acting as a dissolution accelerator.
On the other hand, the IR dye or the like in the positive lithographic printing plate material for infrared laser only serves as a dissolution inhibitor for the non-exposed area, and does not promote dissolution of the exposed area. Therefore, in the positive lithographic printing plate material for infrared laser, in order to obtain a difference in solubility between the non-exposed portion and the exposed portion, a binder resin having high solubility in an alkaline developer must be used in advance. In other words, the state before development becomes unstable.

In order to solve the above problems, a two-layer recording layer comprising a lower layer containing a copolymer having a sulfonamide group and the like, and an upper layer containing an alkaline aqueous solution-soluble resin having a phenolic hydroxyl group and a photothermal conversion agent, A provided lithographic printing plate precursor is proposed, and it is described that sensitivity, development latitude, and printing durability are improved (see Patent Document 1).
JP 11-218914 A

However, the development latitude and the printing durability are still insufficient in order to cope with various practical use conditions even by the above technique, and further improvements are required.
An object of the present invention is to provide a positive lithographic printing plate precursor for infrared laser for direct plate-making having excellent development latitude and high printing durability, which has been made in view of the above problems. is there.

  As a result of extensive research, the inventor has provided two or more positive-type recording layers containing a water-insoluble and alkali-soluble resin on the support and increasing the solubility in an aqueous alkali solution by infrared laser exposure. And any one of the layers contains an infrared absorber, and the water-insoluble and alkali-soluble resin in the lowermost layer of the recording layer is a blend of a resin having a Tg of 110 ° C. or higher and a resin having a Tg of 90 ° C. or lower. The above-mentioned problem can be solved by a planographic printing plate precursor comprising

  According to the present invention, it is possible to provide a positive lithographic printing plate precursor for infrared laser for direct plate making having excellent development latitude and high printing durability.

The lithographic printing plate precursor of the present invention comprises, on a support, two or more positive recording layers that contain a water-insoluble and alkali-soluble resin and increase the solubility in an aqueous alkali solution by infrared laser exposure. The layer contains an infrared absorber, and the water-insoluble and alkali-soluble resin in the lowermost layer of the recording layer comprises two blends of a resin having a Tg of 110 ° C. or higher and a resin having a Tg of 90 ° C. or lower. It is characterized by.
The water-insoluble and alkali-soluble resin in the lowermost layer is preferably composed of a blend of a resin having a Tg of 120 ° C. or higher and a resin having a Tg of 85 ° C. or lower.
When blending alkali-soluble resins, the blend ratio (high Tg resin / low Tg resin) is preferably 90/10 to 10/90 (mass ratio), and the more preferable blend ratio (high Tg resin / low Tg resin) is It is 80 / 20-60 / 40 (mass ratio).

  As described above, blending high-Tg resin with alkali-soluble resin that constitutes the bottom layer can increase the strength of the film and improve printing durability, and blend with low-Tg resin to increase the solubility of the film and develop it. Can be improved.

The lithographic printing plate precursor according to the invention has two or more recording layers, but other layers such as a surface protective layer, an undercoat layer, an intermediate layer, and a backcoat layer can be further provided as desired.
Hereinafter, the constituent elements of the lithographic printing plate precursor according to the invention will be described in detail.

[Water-insoluble and alkali-soluble resin]
In the present invention, the water-insoluble and alkali-soluble resin (hereinafter simply referred to as alkali-soluble resin) used for the recording layer is water-insoluble and has an acidic group on the main chain and / or side chain in the polymer. It is a polymer to be contained, and includes a homopolymer, a copolymer or a mixture thereof. Therefore, the recording layer according to the present invention has a property of dissolving when contacted with an alkaline developer.

The alkali-soluble resin used in the recording layer of the present invention is not particularly limited as long as it is a conventionally known resin, but (1) a phenolic hydroxyl group, (2) a sulfonamide group, (3) an active imide group, and ( 4) It is preferably a polymer compound having any functional group of a carboxyl group in the molecule. (Hereinafter, these functional groups (1) to (4) are also referred to as specific functional groups.)
Examples of the polymer compound having the specific functional group include, but are not limited to, the following.

(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 thereof 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 the polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer comprising a low molecular compound having at least one unsaturated bond polymerizable with the phenolic hydroxyl group is homopolymerized, or other polymerizable property is added to the monomer. Examples thereof include a polymer compound obtained by copolymerizing monomers.

  Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid 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- Hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) Preferred are ethyl acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, and the like. Can be used.

  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. A condensation polymer 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 at least one sulfonamide group —NH—SO ₂ — in which at least one hydrogen atom is bonded on a nitrogen atom and one polymerizable unsaturated bond in one molecule. And a polymerizable monomer comprising a low molecular weight compound. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group, and an unsubstituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

(3) The alkali-soluble resin having an active imide group is obtained by homopolymerizing a polymerizable monomer composed of a low molecular compound having at least one active imide group and one polymerizable unsaturated bond in one molecule. Examples thereof include a polymer compound or a polymer compound obtained by copolymerizing the monomer with another polymerizable monomer.
Specific examples of such a monomer include N- (p-toluenesulfonyl) methacrylamide and N- (p-toluenesulfonyl) acrylamide.

  (4) As the alkali-soluble resin having a carboxyl group, for example, a polymerizable monomer comprising a low molecular compound having at least one carboxyl group and polymerizable unsaturated group in the molecule is homopolymerized, or other than this monomer. And a polymer compound obtained by copolymerizing the polymerizable monomer. Specific examples of the polymerizable monomer having a carboxyl group include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, and itaconic acid. Also, monoesters of hydroxyl groups of acrylates or methacrylates having a hydroxyl group in the side chain (for example, 2-hydroxyethylethyl acrylate or methacrylate) and dibasic acids (for example, succinic acid, glutaric acid, phthalic acid, etc.) The unsaturated carboxylic acid which is is also preferable.

  Furthermore, as the alkali-soluble resin of the present invention, a polymer compound obtained by polymerizing two or more of the four kinds of polymerizable monomers having a specific functional group, or other polymerizable compounds to these two or more kinds of polymerizable monomers. Polymer compounds obtained by copolymerizing monomers are also suitable. When a polymerizable monomer having a phenolic hydroxyl group is copolymerized with a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imide group, the blending mass ratio of these components is 50:50 to 5 : 95, preferably 40:60 to 10:90.

In the present invention, when the alkali-soluble resin is a copolymer of the polymerizable monomer having the specific functional group and another polymerizable monomer, the monomer having the specific functional group imparting alkali solubility is 10 mol. %, Preferably 20 mol% or more.
Examples of other monomer components copolymerized with a polymerizable monomer having a specific functional group include the compounds listed in the following (m1) to (m11), but are not limited thereto.

(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

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

  As a method for copolymerization of the monomer, a conventionally known graft copolymerization method, block copolymerization method, random copolymerization method, or the like can be used.

  In addition to the above, examples of the alkali-soluble resin suitably used in the present invention include a polyurethane resin having a carboxyl group.

  Examples of the polyurethane resin having a carboxyl group include alkali developer-soluble polyurethane resins having a carboxyl group described in JP-A Nos. 5-281718 and 11-352691. Specifically, it is a polyurethane resin having as a basic skeleton a structural unit represented by a reaction product of a diisocyanate compound and a diol compound having a carboxyl group. As the diol compound, a diol compound having no carboxyl group is preferably used in combination for the purpose of adjusting the carboxyl group content and controlling the physical properties of the polymer.

  Examples of the diisocyanate compound include 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4 , 4′-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate and the like; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, Aliphatic diisocyanate compounds such as dimer acid diisocyanate; isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2 , 4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane and the like alicyclic diisocyanate compounds; adducts of 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate, etc. And diisocyanate compounds which are reaction products of diols and diisocyanates.

  Examples of the diol compound having a carboxyl group include 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (2-hydroxyarea) propionic acid, and 2,2-bis. (3-hydroxypropyl) propionic acid, bis (hydroxymethyl) acetic acid, bis (4-hydroxyphenyl) acetic acid, 2,2-bis (hydroxymethyl) butyric acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, Examples include tartaric acid, N, N-dihydroxyethylglycine, N, N-bis (2-hydroxyethyl) -3-carboxy-propionamide and the like.

  Examples of other diol compounds include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, 1,3-butylene glycol, 1,6- Hexanediol, 2-butene-1,4-diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecane dimethanol, Hydrogenated bisphenol A, hydrogenated bisphenol F, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, bisphenol F ethylene oxide Adduct, propylene oxide adduct of bisphenol F, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-xylylene glycol, dihydroxyethyl sulfone, bis (2- Hydroxyethyl) -2,4-tolylenedicarbamate, 2,4-tolylene-bis (2-hydroxyethylcarbamide), bis (2-hydroxyethyl) -m-xylylenedicarbamate, bis (2-hydroxyethyl) isophthalate Etc.

  As other diol compounds, in addition to the above, a polyether diol compound, a polyester diol compound, a polycarbonate diol compound, or the like can be preferably used. Specific examples include, but are not limited to, the following compounds. N in the specific examples represents an integer of 2 or more.

  In addition to the above, the polyurethane resin suitable for the present invention includes a polyurethane resin having a structural unit derived from a compound obtained by ring-opening tetracarboxylic dianhydride with a diol compound as a basic skeleton. Examples of the method for introducing the structural unit into the polyurethane resin include: a) a method in which a compound having an alcohol terminal obtained by ring-opening tetracarboxylic dianhydride with a diol compound and a diisocyanate compound are reacted; b) There is a method of reacting an alcohol-terminated urethane compound obtained by reacting a diisocyanate compound under an excess of a diol compound with tetracarboxylic dianhydride.

  Moreover, the molecular weight of the polyurethane resin of the present invention is preferably 1000 or more in weight average, and more preferably in the range of 5,000 to 500,000.

  As the alkali-soluble resin used in the upper layer of the recording layer of the present invention, among the above alkali-soluble resins, strong hydrogen bonding occurs in the non-exposed area, and some hydrogen bonds are easily released in the exposed area. In this respect, a resin having a phenolic hydroxyl group is more preferable. More preferred is a novolac resin. A weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 are preferred.

  As the alkali-soluble resin used in the lower layer of the recording layer of the present invention (the lowermost layer in the case of two or more recording layers), among the alkali-soluble resins, a resin having a Tg of 110 ° C. or more and a resin having a Tg of 90 ° C. or less Are used in a blend. As a kind of resin, among the alkali-soluble resins, an alkali-soluble resin other than the novolak resin is preferable. Of these, acrylic resins and polyurethane resins are more preferable. Among acrylic resins, those having a sulfonamide group are particularly preferred. A resin having a Tg of 110 ° C. or higher and a resin having a Tg of 90 ° C. or lower can be used in combination of two or more resins.

  A preferable blend ratio of a resin having a Tg of 110 ° C. or more and a Tg of 90 ° C. or less is high Tg resin / low Tg resin = 90/10 to 10/90 (mass ratio), and further, high Tg resin / low Tg resin. = 75/25 to 50/50 (mass ratio) is more preferable.

As a method for changing the Tg of the alkali-soluble resin, there is a method of adjusting the content of a polar group, an oriented group, or a rigid group in the alkali-soluble resin molecule. Specific examples of such groups include amide groups, carbonyl groups, and aromatic ring groups.
For example, in an N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer, by changing the copolymerization molar ratio of each monomer from 50/20/30 to 20/30/50, Tg is , From 140 ° C to 90 ° C.

  The Tg of the resin is measured by a known DSC (differential scanning calorimeter) method, dynamic viscoelasticity method or the like. In this invention, it measured using DSC-2 of Perkin-Elmer.

  The alkali-soluble resin is used in an added amount of 30 to 99% by mass, preferably 40 to 95% by mass, particularly preferably 50 to 90% by mass in the total solid content of the recording layer. Within this range, good printing durability can be obtained.

[Infrared absorber]
In the present invention, the infrared absorber that can be contained in the recording layer is not particularly limited as long as it absorbs infrared light and generates heat, but the wavelength of the infrared laser used for image exposure can be used. Are preferably used, and various dyes known as infrared absorbing dyes can be used.

  As the dye, commercially available dyes and known dyes 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.

  Examples of such dyes that absorb infrared light or near infrared light include JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, US Pat. Cyanine dyes described in JP 973,572, etc., methine dyes described in JP-A 58-173696, JP-A 58-181690, JP-A 58-194595, etc. JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Naphthoquinone dyes described, squarilium dyes described in JP-A-58-112792, etc., cyanine dyes described in British Patent No. 434,875, and the like. That.

Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzoates described in US Pat. No. 3,881,924 are also preferred. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (U.S. Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-2220143, 59-41363, 59-84248, 59-84249, 59-146063, 59-146061, and pyranyl compounds described in JP-A-59-216146 Dyes, pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, etc., and Japanese Patent Publication Nos. 5-13514 and 5-19702 Pyrylium compounds disclosed in distribution is, as commercially available products, Eporin Co. Epolight III-178, Epolight III-130, Epolight III-125 and the like are particularly preferably used.
Another particularly preferable example of the dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  In the present invention, since the thickness of the recording layer that contributes to image formation is thin, it is necessary to select an infrared-absorbing dye that can form a good image in as small an amount as possible. From this viewpoint, a cyanine dye is preferable. Preferred cyanine dyes include those represented by the following general formula (I).

In the general formula (I), X ¹ represents a halogen atom, or X ² -L ^1. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.
Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned.
Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred.
Z ¹⁻ represents a counter anion. However, when the cyanine dye has an anionic substituent and the charge is neutralized in the molecule, Z ¹⁻ is not necessary. Preferred Z ¹⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of storage stability of the recording layer coating solution. Hexafluorophosphate ion and aryl sulfonate ion.

  Specific examples of the cyanine dye represented by formula (I) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.

These dyes can be added in a proportion of 0.01 to 50% by mass, preferably 0.1 to 10% by mass, particularly preferably 0.5 to 10% by mass, based on the total solid content of each recording layer. Within this range, good sensitivity can be obtained without deteriorating the uniformity and durability of the recording layer.
These dyes may be added directly to the recording layer together with other components, or another layer may be provided and added thereto. In the case of another layer, it is desirable to provide a layer adjacent to the recording layer and add it there. Moreover, although it is preferable from a viewpoint of a sensitivity that this infrared rays absorption dye and the said alkali-soluble resin are contained in the same layer, another layer may be sufficient.

[Other ingredients]
Various additives can be further added to the upper and lower recording layers of the present invention as required. For example, a fluorine-containing polymer can be added for the purpose of improving the development resistance of the image area. Examples of the fluorine-containing polymer used in the recording layer include fluorine-containing monomer copolymers as described in JP-A Nos. 11-288093 and 2000-187318.

Preferable specific examples include acrylic polymers containing fluorine of P-1 to P-13 described in JP-A No. 11-288093 and A-1 to JP-A No. 2000-187318. A fluorine-containing polymer obtained by copolymerizing a fluorine-containing acrylic monomer of A-33 with an arbitrary acrylic monomer can be exemplified.
As the molecular weight of the fluorine-containing polymer mentioned above, those having a weight average molecular weight of 2000 or more and a number average molecular weight of 1000 or more are preferably used. More preferably, the weight average molecular weight is 5000 to 300000, and the number average molecular weight is 2000 to 250,000.

In addition, as the fluorine-containing polymer, a commercially available fluorine-based surfactant that is a compound having the preferred molecular weight can also be used. As specific examples, MegaFuck F-171, F-173, F-176, F-183, F-184, F-780, F-781 (all trade names) manufactured by Dainippon Ink & Chemicals, Inc. are used. Can be mentioned.
One kind of these fluorine-containing polymers may be used, or two or more kinds may be used in combination.

  The addition amount is 1.4% by mass or more based on the solid content of the recording layer as a requirement of the present invention. A preferable addition amount is 1.4 to 5.0% by mass. Within this range, a good development latitude improvement effect can be obtained without causing the surface of the recording layer to become hardly soluble or to reduce sensitivity.

  Other additives for the recording layer include, for example, thermal decomposition of onium salts, o-quinonediazide compounds, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, and the like. Substances that can be reduced. Use of this substance in combination is preferable from the standpoint of improving dissolution inhibition of the image area in the developer. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts.

Preferable examples of the onium salt used in the present invention include SI Schlesinger, Photogr. Sci. Eng., 18,387 (1974), TS Bal et al, Polymer, 21, 423 (1980), and JP-A-5-158230. No. 4,069,055, US Pat.No. 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecules, 17, 2468 (1984), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055 and 4,069,056, JVCrivello et al, Macromorecules, 10 (6) , 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Pat.Nos. 5,041,358, 4,491,628, JP-A-2-150848, JP-A-2-150848 Iodonium salt described in each publication No. 2-296514, JVCrivello et al, Polymer J. 17, 73 (1985), JVCrivello et al. J. Org. Chem., 43, 3055 (1978), WR Watt et al, J . PolymerSci., Polymer Chem. Ed., 22, 1789 (1984), JV Crivello et al, Polymer Bull., 14, 279 (1985), JV Crivello et al, Macromorecules, 14 (5), 1141 (1981), JVCrivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979), European Patent Nos. 370,693, 233,567, 297,443, 297,442, U.S. Pat. 3,902,114, 4,491,628, 5,041,358, 4,760,013, 4,734,444, 2,833,827, German Patents 2,904,626, 3,604,580, 3,604,581 Selenonium salts described in Crivello et al, Macromorecules, 10 (6), 1307 (1977), JV Crivelloet al, J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), CS Wen et al, Teh , Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
In the present invention, a diazonium salt is particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.

  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, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  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 339-352 of "Light Sensitive Systems" by Korser can be used, but in particular o-reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. Preferred are sulfonic acid esters or sulfonic acid amides of quinonediazide. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of phenol and formaldehyde resins 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 47-5303, JP 48-63802, JP 48-63803, JP 48-96575, JP 49-38701, JP 48-13354, Kosho 41-11222, Shoko 45-9610, Shoko 49-17481, U.S. Patent 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825 , British Patent Nos. 1,227,602, 1,251,345, 1,267,005, 1,329,888, 1,330,932, German Patent No. 854,890, etc. it can.

The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of each recording layer. 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 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass.

  Further, for the purpose of enhancing the discrimination of images and the resistance to scratches on the surface, a perfluoroalkyl group having 3 to 20 carbon atoms in the molecule as described in JP-A-2000-87318 is disclosed. A polymer having 2 or 3 (meth) acrylate monomers as polymerization components can be used in combination.

Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride, and trachlorophthalic 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. Examples of phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 4,4′-bishydroxyphenylsulfone, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4 -Hydroxybenzophenone, 4,4 ', 4 "-trihydroxytriphenylmethane, 4,4', 3", 4 "-tetrahydroxy-3,5,3 ', 5'-tetramethyltriphenylmethane Furthermore, examples of organic acids include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric esters and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Examples of acids include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and p-toluenesulfinic acid. Ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-methoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene Examples include -1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like.
The proportion of the cyclic acid anhydride, phenols, and organic acids in each recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 5% by mass, and particularly preferably 0.1 to 10%. % By mass.

  In the recording layer of the present invention, a nonionic surfactant as described in JP-A-62-251740 or JP-A-3-208514 is used in order to increase the processing stability against development conditions. Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane-based compounds as described in EP 950517, JP-A-11 A copolymer containing a fluorine monomer as described in Japanese Patent No. 288093 can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.). As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, DBE-621, DBE-712, DBP- manufactured by Chisso Corporation. Polyalkylene oxide-modified silicones such as 732, DBP-534, and Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the printing plate material is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

In the recording layer of the present invention, a print-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, for example, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A Nos. 50-36,209 and 53-8128, Trihalomethyl compounds and salts described in JP-A Nos. 53-36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440 Examples of such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images. Examples of other photoacid releasing agents include various o-naphthoquinonediazide compounds described in JP-A-55-62444; 2-trihalomethyl-5--5 described in JP-A-55-77742. Examples include aryl-1,3,4-oxadiazole compounds; diazonium salts.

  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 at a ratio 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 can be added to the recording layer and the lower layer coating solution 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.

[Formation of recording layer]
The lithographic printing plate precursor of the present invention can be produced by sequentially applying a recording layer lower layer coating solution obtained by dissolving the above-mentioned components in a solvent and a recording layer upper layer coating solution in sequence on a suitable support. it can.
Suitable solvents for coating the lower and upper recording layers 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, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, etc. However, the present invention is not limited to this. 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.

In principle, the lower layer and the upper layer are preferably formed by separating two layers.
As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between a component contained in the lower layer and a component contained in the upper layer, or after applying the upper layer, a solvent is rapidly used. However, it is not limited to these methods.

  As a method of utilizing the difference in solvent solubility between the component contained in the lower layer and the component contained in the upper layer, a method using a solvent that does not dissolve the alkali-soluble resin contained in the lower layer when applying the upper layer coating solution. Can be mentioned. Thereby, even if it carries out 2 layer application | coating, it becomes possible to isolate | separate each layer clearly and to make a coating film. For example, as the lower layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the upper layer component is selected, and the lower layer is applied using a solvent system that dissolves the lower layer component. -It is possible to form two layers by drying and then dissolving the upper layer mainly composed of alkali-soluble resin with methyl ethyl ketone, 1-methoxy-2-propanol, etc., and applying and drying.

  When applying a method that uses a solvent that does not dissolve the alkali-soluble resin contained in the lower layer when applying the upper layer coating solution, the upper layer coating solvent does not dissolve in the solvent that dissolves the alkali-soluble resin contained in the lower layer. You may mix and use a solvent. By changing the mixing ratio of the two solvents, interlayer mixing between the upper layer and the lower layer can be arbitrarily controlled. When the ratio of the solvent that dissolves the alkali-soluble resin in the lower layer increases, a part of the lower layer dissolves when the upper layer is applied, and after drying, it is contained as a particulate component in the upper layer. Protrusions are made and scratch resistance is improved. On the other hand, when the lower layer components are dissolved into the upper layer, the film quality of the lower layer is lowered, and the chemical resistance tends to be lowered. In this way, by controlling the mixing ratio in consideration of each physical property, various characteristics can be expressed, and further, partial compatibility between layers described later can be caused.

  From the viewpoint of the effect of the present invention, when the above mixed solvent is used as the upper layer coating solvent, the solvent for dissolving the lower layer alkali-soluble resin should be 80% by mass or less of the upper layer coating solvent. From the viewpoint, it is preferably in the range of 10 to 60% by mass in consideration of scratch resistance.

  Next, after applying the second layer (upper layer), as a method of drying the solvent very quickly, high-pressure air is blown from a slit nozzle installed substantially perpendicular to the running direction of the web, or a heating medium such as steam. Can be achieved by applying thermal energy as conduction heat from the lower surface of the web from a roll (heating roll) supplied inside, or by combining them.

Various methods can be used as a method for applying each layer such as a recording layer in the present invention. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, Examples thereof include roll coating.
In particular, in order to prevent damage to the lower layer when the upper layer is applied, the upper layer application method is preferably a non-contact type. Further, although it is a contact type, it is possible to use bar coater coating as a method generally used for solvent-based coating, but it is desirable to perform coating by forward rotation in order to prevent damage to the lower layer.

Coating amount after drying of a lower layer of the lithographic printing plate precursor of the present invention is preferably in the range of 0.5 to 1.5 g / m ^2, more preferably in the range of 0.7~1.0g / m ² It is. Within this range, no residual film is generated and good printing durability can be obtained.
The coating amount after drying of the recording layer upper layer is preferably in the range of 0.05 to 1.0 g / m ^2, more preferably in the range of 0.07~0.7g / m ^2. Within this range, good sensitivity, development latitude, and film characteristics can be obtained.

  In the lower layer or upper layer coating solution in the present invention, a surfactant for improving coating properties, for example, a fluorine-based surfactant as described in JP-A-62-170950 may be added. it can. A preferable addition amount is 0.01 to 1% by mass of the total solid content of the coating solution, and more preferably 0.05 to 0.5% by mass.

[Support]
The support used in the present invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal Plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, Polyvinyl acetal, etc.), paper or plastic film on which a metal as described above is laminated or deposited.

As the support used in the present invention, 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. Thus, the composition of the aluminum plate applied to the present invention is not specified, and a conventionally known and publicly available aluminum plate 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 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Such an aluminum plate can be subjected to a surface treatment such as a roughening treatment, an anodizing treatment, or a hydrophilizing treatment as necessary. Hereinafter, such surface treatment will be described.

Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired.
The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. As an electrolyte used for anodizing treatment of an 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 less than 1.0 g / m ² , the printing durability will be insufficient, or the non-image area of the lithographic printing plate will be easily scratched. Adhering so-called “scratch stains” are likely to occur.

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

[Undercoat layer]
The lithographic printing plate precursor according to the present invention is provided by laminating the lower layer and the upper layer on a support. If necessary, an undercoat layer may be provided between the support and the lower layer. it can.
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 -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

It is also preferred that the undercoat layer contains a compound having an onium group. The compounds having an onium group are described in detail in JP-A No. 2000-10292, JP-A No. 2000-108538, JP-A No. 2000-241962, and the like.
Among them, preferred is at least one compound selected from the group of polymer compounds having a structural unit represented by poly (p-vinylbenzoic acid) in the molecule. Specific examples include a copolymer of p-vinylbenzoic acid and vinylbenzyltriethylammonium chloride, a copolymer of p-vinylbenzoic acid and vinylbenzyltrimethylammonium salt, and the like.

This organic 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 obtained by dissolving the above organic compound in an 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 organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound is applied on a support 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 coating solution or immersion solution can be adjusted to a pH in the range of 1 to 12 with a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid.

The coating amount of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . Within this range, good printing durability can be obtained.

[Plate making]
The positive lithographic printing plate precursor produced as described above is usually subjected to image exposure and development processing.
Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Further, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are also used. Examples of the laser beam include a helium / neon laser, an argon laser, a krypton laser, a helium / cadmium laser, and a KrF excimer laser. In the present invention, a light source having a light emission wavelength from the near infrared region to the infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.

An alkaline aqueous solution is used as the developer and replenisher for the lithographic printing plate of the present invention.
The developer applicable to the present invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. 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.

  Furthermore, as the lithographic printing plate developer of the present invention, an alkaline aqueous solution comprising a non-reducing sugar and a base can be used. Non-reducing sugar means a saccharide that does not have a free aldehyde group or ketone group and therefore has no reducing ability. Trehalose-type oligosaccharides in which reducing groups are bonded to each other, and a configuration in which a reducing group of saccharides and a non-saccharide are bonded. Sugar sugars are classified into sugar alcohols reduced by hydrogenation of sugars. Any of these is preferably used in the present invention.

Examples of trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides 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 and allozulcit. Furthermore, maltitol obtained by hydrogenation of a disaccharide and a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide are preferably used. Among these, sugar alcohol and saccharose are particularly preferred non-reducing sugars, and D-sorbite, saccharose, and reduced syrup are particularly preferred because they have a buffering action in an appropriate pH region and are inexpensive.
These non-reducing sugars can be used alone or in combination of two or more thereof, and the proportion of the non-reducing sugar in the developer is preferably from 0.1 to 30% by mass, and more preferably from 1 to 20% by mass.
A conventionally known alkaline agent can be used as the base to be combined with the non-reducing sugar. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, Examples include inorganic alkali agents such as ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate. 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 also used.
These alkali agents are used alone or in combination of two or more. Among these, sodium hydroxide and potassium hydroxide are preferable. The reason is that the pH can be adjusted in a wide pH range by adjusting the amount added to the non-reducing sugar. Further, trisodium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they themselves have a buffering action.

  When developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developer is added to the developer, so that a large amount of PS can be obtained without replacing the developer in the developer tank for a long time. It is known that plates can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added. The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. When the lithographic printing plate precursor according to the invention is used as a printing plate, these treatments can be used in various combinations as post-treatments.

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

  A method for processing a lithographic printing plate precursor according to the present invention will be described. When there is an unnecessary image portion on the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution 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. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-5-174842 can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with a higher printing durability, a burning treatment is performed. Is given. 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. Moreover, 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 subjected to the burning treatment can be appropriately subjected to known treatments such as washing and gumming as needed, but when a surface-conditioning solution containing a water-soluble polymer compound is used. 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.
[Example 1]

(Production of support)
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.014 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.03% by mass, and the balance is prepared by using an aluminum alloy of Al and inevitable impurities. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Further, after heat treatment was performed at 500 ° C. using a continuous annealing machine, an aluminum plate having a thickness of 0.24 mm was finished by cold rolling. After making this aluminum plate width 1030mm, it used for the surface treatment shown below.

In the surface treatment, the following various treatments (a) to (j) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.
(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) Etching treatment with alkali agent The aluminum plate obtained above is subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. 10 g / m ^{2 was} dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass 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 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 80 ° C.
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. Then, water washing by spraying was performed.

(E) Alkaline etching treatment An aluminum plate is subjected to an etching treatment by spraying at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.20 g / m ^2. The smut component mainly composed of aluminum hydroxide generated when the electrochemical surface roughening process is performed using the alternating current of the previous stage is removed, and the edge portion of the generated pit is melted to smooth the edge portion. I made it. Then, water washing by spraying was performed.

(F) Desmutting treatment Desmutting treatment was carried out by spraying with a 25% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(G) Anodizing treatment Anodizing device of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode length 2.4 m each) Anodizing was performed using this. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 43 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

(H) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment was immersed in a treatment tank of 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silicate. Salt treatment (silicate treatment) was performed. Then, water washing by spraying was performed.

(I) Formation of undercoat layer On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution (1) having the following composition was applied and dried at 80 ° C for 15 seconds. A coating film was formed. The coating amount of the coating film after drying was 15 mg / m ² .

<Undercoat liquid (1)>
・ The following compound 1 0.3g
・ Methanol 100g
・ Water 1g

(Recording layer application)
The following coating solution for the lower layer was applied to the obtained support so that the coating amount after drying was 0.85 g / m ^2, and then Wind Control was set to 7 with PERFECT OVEN PH200 manufactured by Tabai Co., Ltd. Dry at 50 ° C. for 50 seconds. Thereafter, the recording layer upper layer coating solution was applied so that the coating amount after drying was 0.15 g / m ^2, and then dried at 120 ° C. for 1 minute to obtain a planographic printing plate precursor 1.

<Coating liquid for lower layer>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 50/20/30) copolymer (weight average molecular weight 30,000, Tg = 140 ° C.) 1.280 g
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 20/30/50) copolymer (weight average molecular weight 20,000, Tg = 90 ° C.) 0.853 g
・ Cyanine dye A (the following structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalenesulfonate 0.10g
・ Fluorosurfactant (Surface improving surfactant) 0.035 g
[Megafuck F781F, manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

  In addition, the molecular weight of the alkali-soluble resin for the lower layer was measured with a gas chromatography apparatus (HLC-8020, manufactured by Tosoh Corporation), and Tg was measured with a DSC apparatus (Mettler DSC30, manufactured by Mettler). .

<Coating liquid for recording layer upper layer>
・ M, p-cresol novolak 0.2846g
(M / p ratio = 6/4, weight average molecular weight 4500, containing unreacted cresol 0.8% by mass)
・ Cyanine dye A (the above structure) 0.075 g
・ Behenamide 0.060g
-Fluorosurfactant (Surface improving surfactant) 0.022g
[Megafuck F781F, manufactured by Dainippon Ink & Chemicals, Inc.]
・ Image formation improved fluorosurfactant 0.120g
[Megafuck F780 (30% by mass), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 15.1g
-1-methoxy-2-propanol 7.7g

[Example 2]
A lithographic printing plate precursor 2 was obtained in the same manner as in Example 1 except that the recording layer upper layer coating solution and lower layer coating solution of Example 1 were changed to the following.

<Coating liquid for lower layer>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 25/25/50) copolymer (weight average molecular weight 50,000, Tg = 85 ° C.) 1.919 g
・ Polyurethane resin made by Synthesis 1 below (1)
(Weight average molecular weight 150,000, Tg = 160 ° C.) 0.213 g
・ Cyanine dye A (the above structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorosurfactant (Surface improving surfactant) 0.035 g
[Megafuck F176 (20% by mass), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Image formation improved fluorosurfactant 0.120g
[Megafuck MCF-312 (30% by mass), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

[Synthesis 1: Synthesis of the above polyurethane resin (1)]
In a 500 ml three-necked flask, 125 g of 4,4′-diphenylmethane diisocyanate and 67 g of 2,2-bis (hydroxymethyl) propionic acid were dissolved in 290 ml of dioxane. After adding 1 g of N, N-diethylaniline, the mixture was stirred for 12 hours under reflux of dioxane. After the reaction, it was added little by little to a solution of 4 L of water and 40 mL of acetic acid to precipitate a polymer. This solid was vacuum-dried to obtain 185 g of polyurethane resin (1). The acid content was 2.47 meq / g. When the molecular weight was measured by GPC, the weight average (polystyrene standard) was 150,000.

<Upper layer coating solution>
・ M, p-cresol novolak 0.2846g
(M / p ratio = 6/4, weight average molecular weight 4500, containing unreacted cresol 0.8% by mass)
・ Cyanine dye A (the above structure) 0.095 g
・ Polyethylene oxide (average molecular weight 1000) 0.06 g
-Fluorosurfactant (Surface improving surfactant) 0.022g
[Megafuck F781F, manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 15.1 g
・ 1-methoxy-2-propanol 7.7 g

Example 3
A lithographic printing plate precursor 3 was obtained in the same manner as in Example 1 except that the upper layer coating amount of Example 1 was 0.20 g / m ² .

Example 4
In the production of the support of Example 1, (h) no alkali metal silicate treatment was performed, and (i) in the formation of an undercoat layer, an undercoat solution (2) having the following composition was applied, and at 80 ° C. for 30 seconds. A lithographic printing plate precursor 4 was obtained in the same manner as in Example 1 except that it was dried and the coating amount after drying was 10 mg / m ² .

<Undercoat liquid (2)>
β-Alanine 0.1g
Phenylsulfonic acid 0.05g
40g of methanol
60g of pure water

Example 5
(Production of support)
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.025 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.03% by mass, and the balance is prepared by using an aluminum alloy of Al and inevitable impurities. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Further, after heat treatment was performed at 500 ° C. using a continuous annealing machine, an aluminum plate having a thickness of 0.30 mm was finished by cold rolling. After making this aluminum plate 1030 mm in width, the following surface treatment was continuously performed.

(A) Mechanical roughening treatment (brush grain method)
While supplying an aqueous suspension (specific gravity 1.1 g / cm ³ ) of an abrasive (pumice) as a polishing slurry liquid to the surface of the aluminum plate, a mechanical surface roughening treatment was performed with a rotating roller brush. The median diameter of the abrasive was 33 μm. As for the roller-like brush, a nylon brush was planted so as to be dense by making a hole in a stainless steel cylinder having a diameter of 400 mm. 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 distance between the surfaces of the two support rollers (φ250 mm) under the brush was 300 mm. The roller brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus with respect to the load before the roller brush was pressed against the aluminum plate.

(B) Etching treatment with alkali agent The aluminum plate after the mechanical surface-roughening treatment obtained above is sprayed with an aqueous caustic soda solution having a caustic soda concentration of 2.6 mass% and an aluminum ion concentration of 5 mass%, so that the aluminum dissolution amount is 10 g. Etching was performed at / m ² . Then, water washing by spraying was performed. The temperature for the alkali etching treatment was 70 ° C.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying.

(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 10% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 35 ° C.
The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 197 C / dm ^{2 as} the total amount of electricity when the aluminum plate was the anode.
Then, water washing by spraying was performed.

(E) Alkali etching treatment An aluminum plate was subjected to aging treatment by spraying at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 70 ° C. to dissolve the aluminum plate by 3.8 g / m ² . Then, water washing by spraying was performed.

(F) Desmutting treatment A desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washing with water by spraying.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The liquid temperature was 40 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value.
The electrolytic solution used for hydrochloric acid electrolysis was a 5.0% by mass aqueous solution of hydrochloric acid (including 5.0% by mass of aluminum ions). The amount of electricity in hydrochloric acid electrolysis was 60 C / It was dm ^2. The electrolytic layer was a radial cell type.
Then, water washing by spraying was performed.

(H) Alkali etching treatment sodium hydroxide concentration of 4.5 wt%, by spraying an aluminum ion concentration of 0.5 wt% sodium hydroxide aqueous solution, an aluminum dissolution amount 0.16 g / m ² was subjected to etching treatment. Then, water washing by spraying was performed. The temperature for the alkali etching treatment was 70 ° C. Then, water washing by spraying was performed.

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

(J) Anodizing treatment Anodizing device of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode length 2.4 m each) Anodizing was performed using this.
Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 15% by mass (containing 0.5% by mass of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.5 g / m ² .

(K) Alkali metal silicate treatment Alkali metal silicate was obtained by immersing the aluminum support obtained by anodizing treatment in a treatment layer of a 1 mass% aqueous solution of sodium silicate 3 at a temperature of 30 ° C. for 10 seconds. Salt treatment (silicate treatment) was performed. Then, water washing by spraying was performed.

(L) Formation of undercoat layer On the aluminum support after the alkali metal silicate treatment obtained as described above, the coating amount of the coating film after drying was 15 mg / m ^{2 in the same} manner as in Example 1. An undercoat layer was provided.

(Preparation of lithographic printing plate precursor)
A lithographic printing plate precursor 5 was obtained by providing lower and upper recording layers in the same manner as in Example 1 except that the above support was used.

Example 6
In the production of the support of Example 1, (a) no mechanical surface roughening treatment was performed, and (d) in the electrochemical surface roughening treatment, the electrolyte solution temperature was set to 40 ° C. A lithographic printing plate precursor 6 was obtained in the same manner as in Example 1 except that the total amount of electricity at the time was 270 C / dm ² .

Example 7
In the production of the support of Example 5, (a) no mechanical surface roughening treatment was performed, and (d) in the electrochemical surface roughening treatment, the electrolyte solution temperature was set to 40 ° C. A lithographic printing plate precursor 7 was obtained in the same manner as in Example 5 except that the total amount of electricity at the time was 270 C / dm ² .

Example 8
A lithographic printing plate precursor as in Example 1 except that the resin of Tg = 90 ° C. used in the lower layer of Example 1 was changed to a resin having the following structure (weight average molecular weight 30,000, Tg = 80 ° C.). 8 was obtained.

[Comparative Example 1]
A lithographic printing plate precursor 9 was obtained in the same manner as in Example 1 except that the lower layer coating solution of Example 1 was changed to the following.

<Coating liquid for lower layer>
-N-4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 50/20/30) copolymer (weight average molecular weight 30,000, Tg = 140 ° C.) 2.133 g
・ Cyanine dye A (the above structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorine-based surfactant (surfactant with improved coating surface) 0.035 g
[Megafuck F176 (20% by mass), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

[Comparative Example 2]
A lithographic printing plate precursor 10 was obtained in the same manner as in Example 1 except that the lower layer coating solution of Example 1 was changed to the following.

<Coating liquid for lower layer>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 20/30/50) copolymer (weight average molecular weight 20,000, Tg = 90 ° C.) 2.133 g
・ Cyanine dye A (the above structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorine-based surfactant (surfactant with improved coating surface) 0.035 g
[Megafuck F176 (20% by mass), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

[Evaluation of planographic printing plate precursor]
1. Evaluation of development latitude The lithographic printing plate precursors 1 to 8 of the present invention and the lithographic printing plate precursors 9 and 10 of the comparative example were drawn on a Trend setter manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm. Went.
First, each lithographic printing plate precursor exposed under the above-mentioned conditions was used with a PS processor 900H manufactured by Fuji Photo Film Co., Ltd., which was prepared by changing the dilution ratio of the developer DT-1 manufactured by Fuji Photo Film Co., Ltd. The liquid temperature was kept at 30 ° C., and development was performed with a development time of 12 seconds. At this time, it was confirmed whether there was any stain or coloring due to the recording layer residual film with poor development, and the conductivity range of the developer that was able to be developed satisfactorily was obtained. The results are shown in Table 1. A film having a large difference between the upper limit value and the lower limit value of the conductivity range is evaluated as being excellent in development latitude.

2. Evaluation of printing durability A lithographic printing plate obtained by developing with a developer having an electric conductivity range that can be satisfactorily developed under the same conditions as the evaluation of the development latitude, using a printing press manufactured by Komori Corporation. Printed. At this time, every time 10,000 sheets are printed, the printing is continuously performed while wiping the printing plate with a cleaner (CL-2, manufactured by Fuji Photo Film Co., Ltd.). The printing durability with chemical resistance was evaluated by visually observing whether printing was possible. The larger the number of sheets, the better the printing durability. The results are shown in Table 1.

  From Table 1, the lithographic printing plate precursors of Comparative Examples 1 and 2 in which the alkali-soluble resin in the lower layer of the recording layer is composed of a resin having a high Tg or a low resin, either the development latitude or the printing durability is insufficient. On the other hand, it can be seen that both the lithographic printing plate precursors of the present invention are excellent in both development latitude and printing durability.

Claims (1)

  Two or more positive-type recording layers containing a water-insoluble and alkali-soluble resin on the support and increased in solubility in an aqueous alkali solution by infrared laser exposure are provided, and either layer contains an infrared absorber The lithographic printing plate precursor, wherein the water-insoluble and alkali-soluble resin in the lowermost layer of the recording layer comprises two kinds of blends of a resin having a Tg of 110 ° C. or higher and a resin having a Tg of 90 ° C. or lower.