JP2003029411A - Original plate for planographic printing plate and plate making method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive original plate for a planographic printing plate for direct plate making adaptable to an IR laser recording system and excellent in scuffing resistance and to provide a plate making method. SOLUTION: The original plate has an underlayer containing a water-insoluble and alkali-soluble resin and an upper heat sensitive layer containing a water- insoluble and alkali-soluble resin and an IR absorbing dye and having solubility in an alkaline aqueous solution increased by heating in order on a hydrophilic support, the surface hardness of the upper heat sensitive layer is >=0.50 GPa and the original plate is imagewise exposed and then developed with an alkali developing solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording material which can be used as an offset printing master, and more particularly to a so-called direct plate-making infrared laser positive type lithographic printing plate precursor for direct plate making from a digital signal of a computer or the like. The present invention relates to an image forming method.

[0002]

2. Description of the Related Art The development of lasers in recent years has been remarkable, especially solid-state lasers having a light emitting region from the near infrared to the infrared.
Semiconductor lasers have high output and small size can be easily obtained. These lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like.

The positive type lithographic printing plate material for infrared laser is
An alkaline aqueous solution-soluble binder resin and an IR dye that absorbs light to generate heat are essential components, and the IR dye dissolves in the unexposed area (image area) due to the interaction with the binder resin. It acts as a dissolution inhibitor that substantially lowers the property, and in the exposed area (non-image area) the heat generated weakens the interaction between the IR dye and the binder resin and dissolves in an alkaline developer to form a lithographic printing plate. To do. However, in such a positive type lithographic printing plate precursor for infrared laser, the dissolution resistance of the unexposed portion (image portion) to the developing solution and the solubility of the exposed portion (non-image portion) under various use conditions are The difference between the two is not yet sufficient, and there is a problem that overdevelopment or defective development is likely to occur due to changes in use conditions. Further, since the image forming ability of the lithographic printing plate precursor depends on the heat generated by infrared laser exposure on the surface of the recording layer, it is used for image formation by the diffusion of heat near the support, that is, for solubilizing the recording layer. There is also a problem that the amount of heat applied is small, the difference between exposure and non-exposure is small, and highlight reproducibility is insufficient.

For example, for the development latitude, U
A positive-working lithographic printing plate precursor prepared by V-exposure, that is, containing an alkali aqueous solution-soluble binder resin and an onium salt or quinonediazide compound, and the onium salt or quinonediazide compound is contained in an unexposed area (image area). For the conventional lithographic printing plate, which functions as a dissolution inhibitor by interacting with the binder resin, and also functions as a dissolution accelerator by being decomposed by light to generate an acid in the exposed area (non-image area). Although it was not a problem with the original material, U
Since V light is apt to wrap around when V exposure is performed, highlight reproducibility is also a problem.

On the other hand, in the positive-working lithographic printing plate precursor for infrared laser, the infrared absorber only acts as a dissolution inhibitor for the unexposed area (image area) and dissolves the exposed area (non-image area). Does not promote Therefore, in the positive-working lithographic printing plate precursor for infrared laser, in order to obtain a difference in solubility between the unexposed area and the exposed area, a binder resin having a high solubility in an alkaline developer should be used in advance. Inevitably, there were problems such as poor scratch resistance and instability in the state before development.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems, that is, positive type lithographic printing for direct plate making which is suitable for an infrared laser recording system and is excellent in scratch resistance. It is to provide an original plate for plate and a plate making method.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor has constructed a heat-sensitive layer having a two-layer structure of a lower layer and an upper heat-sensitive layer (multilayer type photosensitive layer), The present invention has been completed by finding that the above problems can be solved by setting the surface hardness of the upper heat-sensitive layer to 0.50 GPa or more. That is, the present invention is as follows.

(1) An upper heat-sensitive layer containing a lower layer containing a water-insoluble and alkali-soluble resin, a water-insoluble and alkali-soluble resin and an infrared absorbing dye on a hydrophilic support, and increasing the solubility in an alkaline aqueous solution by heating. A positive planographic printing plate precursor, wherein the upper heat-sensitive layer has a surface hardness of 0.50 GPa or more. (2) The positive planographic printing plate precursor as described in (1) above, wherein the upper heat-sensitive layer has a surface hardness of 0.60 GPa or more. (3) The positive planographic printing plate precursor as described in (1) or (2) above, wherein the upper heat-sensitive layer contains an infrared absorbing dye in an amount of 10% by weight or more. (4) The positive-working lithographic printing plate precursor as described in any of (1) to (3) above, wherein the upper heat-sensitive layer contains an onium-type dissolution inhibitor.

(5) An upper heat-sensitive layer containing a water-insoluble and alkali-soluble resin on a hydrophilic support and a water-insoluble and alkali-soluble resin and an infrared absorbing dye on the hydrophilic support to increase solubility in an alkaline aqueous solution by heating. And are sequentially laminated, and the surface hardness of the upper heat-sensitive layer is 0.50.
A method for making a positive-working lithographic printing plate precursor, which comprises exposing a lithographic printing plate precursor having a GPa or more to imagewise and then developing with an alkali developer. (6) The plate making method of a lithographic printing plate precursor as described in (5) above, wherein the alkali developing solution is an alkaline developing solution containing an organic compound having a buffering action and a base as main components.

One of the features of the positive type lithographic printing plate precursor of the present invention and the plate-making method thereof, which is one of the characteristics of the upper heat-sensitive layer, is also used in Japanese Patent Laid-Open Publication No. 10-326406 for evaluation of hardness which defines the surface hardness. A triboscope manufactured by Heiditron was used. This is a system in which a diamond triangular pyramid indenter is pressed into a sample with an ultra-small load of sub-millinewton order using electrostatic force, and the displacement amount (pushing depth) at that time can be measured in real time. Therefore, it is an effective measuring instrument for determining the material coefficient of the thin film such as the hardness of the thin film of 1 micron or less. However, it is difficult to convert it into the standardized Vickers hardness as in the conventional case, and the mechanical properties of the thin film are given on a new scale.

As a means for achieving the above surface hardness, it is effective to increase the concentration of the infrared absorbing dye in the upper heat sensitive layer. In order to effectively increase the surface hardness, it is important that the content is at least 10% by weight of the upper heat-sensitive layer. It is preferably at least 15% by weight. When this method is applied to a single-layer type heat-sensitive layer, the sensitivity of the heat-sensitive layer is significantly reduced, which is not realistic, but in combination with the lower layer having an alkali-soluble resin, the infrared absorption of the upper heat-sensitive layer is not reduced. It is possible to raise the dye concentration to a predetermined concentration. Further, as another means for achieving the above surface hardness, addition of a dissolution inhibitor to the upper heat-sensitive layer can be performed. As the dissolution inhibitor, any compound can be used as long as it is a compound that reduces the dissolution rate of novolak, but an onium-based dissolution inhibitor is preferable in order to effectively increase the surface hardness. More preferably, it is an ammonium-based dissolution inhibitor. The addition amount of the dissolution inhibitor is from 1 of the upper thermosensitive layer.
It is 15% by weight, preferably 3 to 10% by weight. When this method is applied to a single-layer type heat-sensitive layer, the sensitivity of the heat-sensitive layer is significantly reduced, which is not realistic, but in combination with a lower layer having an alkali-soluble resin, a predetermined amount can be applied to the upper heat-sensitive layer without decreasing the sensitivity. A dissolution inhibitor can be added. However, if the added amount exceeds 15% by weight, there is a concern that the sensitivity may be lowered even in a multilayer system. The above means may be used alone or in combination.

With the above structure and the surface hardness of the upper heat-sensitive layer of 0.
When it is at least 50 GPa, the lithographic printing plate precursor and plate making method of the present invention are compatible with the infrared laser recording system and are excellent in scratch resistance, that is, generation of defects caused by scratches in the image area is suppressed. A positive planographic printing plate precursor for direct plate making can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the positive type lithographic printing plate precursor and plate making method of the present invention will be described in detail. The positive heat-sensitive layer in the present invention has a laminated structure, and an upper heat-sensitive layer provided at a position close to the surface (exposed surface) and a lower layer containing an alkali-soluble resin provided on the side closer to the support. And having. These layers include
All of them must contain a water-insoluble and alkali-soluble resin, and the upper heat-sensitive layer located on the upper side must contain an infrared absorbing dye. Hereinafter, each component of the lithographic printing plate precursor to which the plate making method of the present invention is applied will be described.

[Alkali-soluble polymer] In the present invention,
A water-insoluble and alkali-water-soluble polymer compound used in the upper heat-sensitive layer and the lower layer (hereinafter, appropriately referred to as an alkali-soluble polymer) means that the polymer contains an acidic group in its main chain and / or side chain. Homopolymers, copolymers thereof or mixtures thereof. Therefore, the polymer layer according to the present invention has a property of dissolving when contacted with an alkaline developer. The alkali-soluble polymer used in the lower layer and the upper heat-sensitive layer of the present invention is not particularly limited as long as it is a conventionally known polymer, but (1) phenolic hydroxyl group, (2) sulfonamide group, (3) activity It is preferable that the polymer compound has any functional group of an imide group in the molecule. For example, the following are exemplified, but the invention is not limited thereto.

(1) As the polymer compound having a phenolic hydroxyl group, for example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m
-, P-, or m- / p-mixture may be used) Novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. In addition to the above, the polymer compound having a phenolic hydroxyl group is preferably a polymer compound having a phenolic hydroxyl group in the side chain. As the polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer composed of a low molecular weight compound having at least one unsaturated bond capable of polymerizing with the phenolic hydroxyl group is homopolymerized, or another polymerizable compound is added to the monomer. Examples thereof include polymer compounds 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) ethyl 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 conveniently. The resin having such a phenolic hydroxyl group may be used in combination of two or more kinds. Further, U.S. Pat. No. 4,123,279.
As described in the specification, even if a condensation polymer of phenol and formaldehyde having a C3-8 alkyl group as a substituent, such as t-butylphenolformaldehyde resin and octylphenolformaldehyde resin, is used in combination. Good.

(2) As the alkali-soluble polymer compound having a sulfonamide group, a polymer compound obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the polymerizable monomer with another polymerizable monomer. Is mentioned. Examples of the polymerizable monomer having a sulfonamide group include a sulfonamide group —NH—SO ₂ — having at least one hydrogen atom bonded to a nitrogen atom in one molecule.
And a polymerizable monomer composed of a low molecular weight compound each having one or more polymerizable unsaturated bonds. Among them, a low molecular weight compound having an acryloyl group, an allyl group or a vinyloxy group and a substituted or mono-substituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

(3) The alkali-soluble polymer compound having an active imide group is preferably one having an active imide group in the molecule, and this polymer compound is an unsaturated compound capable of polymerizing with the active imide group in one molecule. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer composed of a low molecular weight compound having one or more bonds, or by copolymerizing the polymerizable monomer with another polymerizable monomer.

Specific examples of such compounds include:
N- (p-toluenesulfonyl) methacrylamide, N
-(P-toluenesulfonyl) acrylamide etc. can be used conveniently.

Further, as the alkali-soluble polymer compound of the present invention, two or more kinds of the above-mentioned polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, and a polymerizable monomer having an active imide group are used. It is preferable to use a polymer compound obtained by polymerizing the above, or a polymer compound obtained by copolymerizing another polymerizable monomer with these two or more polymerizable monomers. 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 weight ratio of these components is 50:50 to 5: 5. It is preferably in the range of 95, particularly preferably in the range of 40:60 to 10:90.

In the present invention, the alkali-soluble polymer is a copolymer of a polymerizable monomer having the above-mentioned phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group or a polymerizable monomer having an active imide group, and another polymerizable monomer. When it is a polymer, the content of the alkali-solubilizing monomer is preferably 10 mol% or more, more preferably 20 mol% or more. When the content of the copolymerization component is less than 10 mol%, the alkali solubility tends to be insufficient, and the effect of improving the development latitude may not be sufficiently achieved.

The monomer components to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group are listed in the following (m1) to (m12). Examples of the compound include, but are not limited to, these. (M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. (M2) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate,
Alkyl acrylates such as hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate and glycidyl acrylate. (M3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid-2-
Alkyl methacrylates such as chloroethyl, glycidyl methacrylate, etc. (M4) acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N
-Acrylamide or methacrylamide such as phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-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 acetate, vinyl chloroacetate,
Vinyl esters such as vinyl butyrate and vinyl benzoate. (M7) Styrenes such as styrene, α-methylstyrene, methylstyrene and 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 etc. (M11) maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N
Unsaturated imides such as-(p-chlorobenzoyl) methacrylamide. (M12) An unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride or itaconic acid.

As the alkaline water-soluble polymer compound,
It is preferable to have a phenolic hydroxyl group from the viewpoint of excellent image formability upon exposure with an infrared laser or the like. For example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde. Resin, phenol / cresol (m-, p-, or m- /
Preference is given to novolak resins such as mixed formaldehyde resins and pyrogallolacetone resins.

As the alkaline water-soluble polymer compound having a phenolic hydroxyl group, further, as described in US Pat. No. 4,123,279,
Carbon number 3 ~, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin
Examples thereof include a condensation polymer of phenol and formaldehyde having the alkyl group of 8 as a substituent.

As a method for copolymerizing the alkaline water-soluble polymer compound, a graft copolymerization method, which is conventionally known,
A block copolymerization method, a random copolymerization method, etc. can be used.

In the present invention, the alkali-soluble polymer is
In the case of a homopolymer or a copolymer of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group, the weight average molecular weight is 2,000 or more and the number average is Those having a molecular weight of 500 or more are preferable. 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 the present invention, when the alkali-soluble polymer is a resin such as phenol formaldehyde resin or cresol aldehyde resin, the weight average molecular weight is 500 to
20,000 and a number average molecular weight of 200 to 10,0.
00 is preferable.

The alkali-soluble polymer used in the lower layer is preferably an acrylic resin. Further, the acrylic resin having a sulfamide group is particularly preferable. Further, as the alkali-soluble polymer used in the upper upper heat-sensitive layer, a strong hydrogen bonding property is generated in the unexposed area, and a phenolic hydroxyl group is generated in the exposed area because some hydrogen bonds are easily released. A resin having is desirable. More preferably, it is a novolac resin.

These alkali-soluble polymer compounds may be used either individually or in combination of two or more, and they are used in an amount of 30 to 99% by weight, preferably 40 to 95% by weight, especially 40 to 95% by weight, based on the total solid content of the heat-sensitive layer. Preferably 50-90
It is used in the addition amount of weight%. If the amount of the alkali-soluble polymer added is less than 30% by weight, the durability of the heat-sensitive layer deteriorates, and if it exceeds 99% by weight, it is not preferable in terms of sensitivity and durability.

[Infrared absorbing dye] In the present invention, the infrared absorbing dye used in the upper heat-sensitive layer is not particularly limited as long as it is a dye that absorbs infrared light and generates heat, and various infrared absorbing dyes known as infrared absorbing dyes can be used. Dyes can be used.

As the infrared absorbing dye according to the present invention, commercially available dyes and known dyes described in the literature (for example, "Handbook of Dyes" edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes,
Examples include dyes such as methine dyes and cyanine dyes. In the present invention, among these dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in a laser that emits infrared light or near infrared light.

Examples of such a dye that absorbs infrared light or near infrared light include, for example, JP-A-58-125246.
JP-A-59-84356 and JP-A-59-2028.
29, JP-A-60-78787, and other cyanine dyes, JP-A-58-173696, and JP-A-5-173966.
8-181690, methine dyes described in JP-A-58-194595, and JP-A-58-112793.
JP-A-58-224793, JP-A-59-481
87, JP-A-59-73996, JP-A-60-52.
940, naphthoquinone dyes described in JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, UK Patent 43
Examples thereof include cyanine dyes described in No. 4,875.

Also, as a dye, US Pat. No. 5,156,
The near-infrared absorption sensitizer described in US Pat. No. 938 is also preferably used, and the substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, JP-A-57-1.
No. 42645 (US Pat. No. 4,327,169), a trimethine thiapyrylium salt, JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363.
No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and the pyrylium compounds described in JP-A-59-2161.
Cyanine dye described in US Pat. No. 4,283,4
The pentamethine thiopyrylium salt described in No. 75, the Japanese Patent Publication No. 513514, and the pyrylium compound disclosed in No. 5-19702 are commercially available products, such as Epolight III-178 manufactured by Eporin Co., Epoli
ght 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 as formulas (I) and (II) in US Pat. No. 4,756,993.

These infrared absorbing dyes can be added not only to the upper heat-sensitive layer but also to the lower layer. The lower layer can also function as a heat-sensitive layer by adding an infrared absorbing dye to the lower layer. When the infrared absorbing dye is added to the lower layer, the same one as the infrared absorbing dye in the upper heat-sensitive layer may be used, or a different one may be used. Further, these infrared absorbing dyes may be added to the same layer as other components, or may be added to another layer provided separately.
When it is formed as another layer, it is preferably added to the layer adjacent to the heat-sensitive layer. The dye and the alkali-soluble resin are preferably contained in the same layer, but they may be contained in different layers. The amount added may be 10 to 50% by weight, preferably 10 to 20% by weight, based on the total solid content of the upper thermosensitive layer composition. Addition amount of dye is 10% by weight
If it is less than 50% by weight, the sensitivity is lowered, and if it exceeds 50% by weight, the sensitivity is remarkably lowered, and further, the uniformity of the heat-sensitive layer is lost.
The durability of the heat sensitive layer becomes poor. Further, it may be added in an amount of 0 to 10% by weight, preferably 0 to 6% by weight, more preferably 0.1 to 5% by weight, based on the total solid content of the lower layer composition. If the amount of the dye added exceeds 10% by weight, the sensitivity will decrease.

As a means for increasing the surface hardness to 0.50 GPa or more, it is possible to increase the concentration of infrared absorbing dye in the upper heat-sensitive layer. In order to effectively increase the surface hardness, it is important that the upper heat-sensitive layer is at least 10% by weight or more. It is preferably at least 15% by weight. When this method is applied to a single-layer type heat-sensitive layer, the sensitivity of the heat-sensitive layer is significantly reduced, which is not realistic, but in combination with the lower layer having an alkali-soluble resin, the infrared absorption of the upper heat-sensitive layer is not reduced. It is possible to raise the dye concentration to a predetermined concentration.

[Other Components] In forming the positive heat-sensitive layer or the lower layer, various additives are added, if necessary, in addition to the above-mentioned essential components unless the effects of the present invention are impaired. can do. The additive may be contained only in the lower layer or only in the upper heat-sensitive layer. Further, it may be contained in both layers. An example of the additive will be described below. For example onium salt,
The combined use of a substance that is thermally decomposable, such as an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, and that substantially reduces the solubility of the alkaline water-soluble polymer compound when not decomposed, It is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developing solution and improving the surface hardness. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts and arsonium salts.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et a
l, Polymer, 21, 423 (1980), JP-A-5-158230
Diazonium salt described in U.S. Pat. No. 4,069,055
No. 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecule
s, 17, 2468 (1984), CS Wen et al, Teh, Proc. Con
f. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Patent Nos. 4,069,055 and 4,069,056, JVCrivello et al, Macromorecules, 10
(6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1
988), European Patent 104,143, US Patent 339,049,
No. 410,201, JP-A-2-150848, JP-A-2-296514, iodonium salts described in JVCrivello et al, Polym
er J. 17, 73 (1985), JV Crivello et al. J.Org.C.
hem., 43, 3055 (1978), WR Watt et al, J. Polymer
Sci., Polymer Chem. Ed., 22, 1789 (1984), JVC
rivello et al, Polymer Bull., 14, 279 (1985), JV
Crivello et al, Macromorecules, 14 (5), 1141 (198)
1), JV Crivello et al, J. PolymerSci., Polymer C
hem. Ed., 17, 2877 (1979), European Patent No. 370,693,
233,567, 297,443, 297,442, U.S. Pat.Nos. 4,933,377, 3,902,114, 410,201, 33
9,049, 4,760,013, 4,734,444, 2,833,
827, German Patents 2,904,626, 3,604,580, and
JV Crivello, sulfonium salts described in 3,604,581
et al, Macromorecules, 10 (6), 1307 (1977), JV Cr
ivello et al, J. Polymer Sci., Polymer Chem. Ed., 1
7, 1047 (1979), selenonium salt, CS Wene
t al, Teh, Proc.Conf.Rad. Curing ASIA, p478 Tokyo,
Examples include arsonium salts described in Oct (1988).
Among the onium salts, diazonium salts and ammonium salts are particularly preferable from the viewpoint of improving the surface hardness. Further, as a particularly preferable diazonium salt, JP-A-5-15823.
Examples of those described in Japanese Patent Application No. 0, particularly preferable ammonium salts include those described in Japanese Patent Application No. 2001-029890.

As the counter ion of the onium salt, 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-sulfonic acid, 2-methoxy-4-hydroxy-5- Examples thereof include benzoyl-benzenesulfonic acid and paratoluenesulfonic acid. Among these, alkylaromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

When an onium-based dissolution inhibitor, preferably an ammonium-based dissolution inhibitor, is used as a means for increasing the surface hardness to 0.50 GPa or more, the addition amount is 1 to 1 of the upper heat-sensitive layer.
It is 5% by weight, preferably 3-10% by weight. When this method is applied to a single-layer type heat-sensitive layer, the sensitivity of the heat-sensitive layer is significantly reduced, which is not realistic, but in combination with a lower layer having an alkali-soluble resin, a predetermined amount can be applied to the upper heat-sensitive layer without decreasing the sensitivity. A dissolution inhibitor can be added. However,
If the amount added exceeds 15% by weight, there is a concern that the sensitivity may be lowered even in a multilayer system.

Further, as described in JP-A-2000-187318, for the purpose of strengthening image discrimination (hydrophobic / hydrophilic discrimination) and resistance to surface scratches, 3 to 20 carbon atoms in the molecule
Having 2 or 3 perfluoroalkyl groups of (meth)
It is preferable to use a polymer having an acrylate monomer as a polymerization component in combination. Such a compound may be contained in either the lower layer or the upper heat-sensitive layer, but it is more effective to contain it in the upper heat-sensitive layer. The amount of addition is 0.1 to 10% by weight in the heat-sensitive layer material.
Is preferable, and more preferably 0.5 to 5% by weight.

A compound that lowers the coefficient of static friction of the surface can be added to the printing plate material of the present invention for the purpose of imparting resistance to scratches. In particular,
Examples thereof include esters of long-chain alkylcarboxylic acids as used in US Pat. No. 6,117,913. Such a compound may be contained in either the lower layer or the upper heat-sensitive layer, but it is more effective that it is contained in the upper heat-sensitive layer located above. The preferable amount of addition is 0.1% in the material forming the layer.
-10% by weight. It is more preferably 0.5 to 5% by weight.

Further, the lower layer or the upper heat-sensitive layer in the present invention may optionally contain a compound having a low molecular weight acidic group. Examples of the acidic group include sulfonic acid, carboxylic acid and phosphoric acid groups. Of these, compounds having a sulfonic acid group are preferable. Specific examples thereof include aromatic sulfonic acids such as p-toluenesulfonic acid and naphthalenesulfonic acid, and aliphatic sulfonic acids.
Such a compound may be contained in either the lower layer or the upper heat-sensitive layer. The amount of addition is preferably 0.05 to 5% by weight in the material forming the layer. It is more preferably 0.1 to 3% by weight. If it exceeds 5%, the solubility of each layer in the developing solution increases, which is not preferable.

Further, in the present invention, various dissolution inhibitors other than those mentioned above may be contained for the purpose of adjusting the solubility of the lower or upper heat-sensitive layer and increasing the surface hardness of the upper heat-sensitive layer. Examples of such dissolution inhibitors include JP-A 11-119.
A disulfone compound or a sulfone compound as disclosed in Japanese Patent No. 418 is preferably used. Such a compound may be contained in either the lower layer or the upper heat-sensitive layer. The preferable amount of addition is 0.05 to 20% by weight in the material constituting each layer. It is more preferably 0.5 to 10% by weight.

Further, cyclic acid anhydrides, phenols and organic acids may be used in combination for the purpose of further improving the sensitivity. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride and tetrachlorophthalic anhydride described in U.S. Pat. No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenyl maleic anhydride, succinic anhydride, pyromellitic dianhydride, etc. can be used. Examples of phenols include bisphenol A, p-nitrophenol, p-
Ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "
-Trihydroxytriphenylmethane, 4,4 ',
3 ", 4" -tetrahydroxy-3,5,3 ', 5'-
Examples thereof include tetramethyltriphenylmethane. Further, as organic acids, there are JP-A-60-88942 and JP-A-2.
-96755, sulfonic acids,
There are sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids and the like. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfuric acid, phenylphosphonic acid, Phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-
1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like can be mentioned. The content of the cyclic acid anhydride, phenols and organic acids in the material constituting the layer is preferably 0.05 to 20% by weight, more preferably 0.1 to 15% by weight, and particularly preferably 0.1. It is 1 to 10% by weight.

In the lower layer or heat-sensitive 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. A typical example of the print-out agent is a combination of a compound that releases an acid when heated by exposure (photo-acid releasing agent) and an organic dye capable of forming a salt. Specifically, o-naphthoquinonediazide-4 described in JP-A Nos. 50-36209 and 53-8128 are disclosed.
-A combination of a sulfonic acid halogenide and a salt-forming organic dye, and JP-A-53-36223 and 54-74728.
No. 60-3626, No. 61-143748, No. 61-151644, and No. 63-58440, and combinations of trihalomethyl compounds and salt-forming organic dyes. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give a clear printout image.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. 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 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl. Violet (CI42535), ethyl violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201).
5) etc. can be mentioned. In addition, JP-A-62-2
The dyes described in Japanese Patent No. 93247 are particularly preferable. These dyes are added in an amount of 0.
It can be added to the printing plate material in a proportion of 01 to 10% by weight, preferably 0.1 to 3% by weight. Further, a plasticizer is added to the printing plate material of the present invention, if necessary, in order to impart flexibility to 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. Oligomers and polymers are used.

The heat-sensitive layer and lower layer of the lithographic printing plate precursor to which the method of the present invention is applied can be usually formed by dissolving each of the above components in a solvent and coating the solution on a suitable support. As the solvent used here, 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-
Examples thereof include methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene, but are not limited thereto. These solvents may be used alone or as a mixture.

The solvent used for coating is preferably selected from those having different solubilities in the alkali-soluble polymer used in the upper heat-sensitive layer and the alkali-soluble polymer used in the lower layer. In other words, when the lower layer is applied and then the upper heat-sensitive layer is applied adjacent thereto, if a solvent capable of dissolving the lower layer alkali-soluble polymer is used as the uppermost layer coating solvent, the mixing at the layer interface is ignored. In some extreme cases, it becomes impossible to form multiple layers and a uniform single layer is formed. As described above, when mixing occurs at the interface between two adjacent layers or when they are compatible with each other and behave like a uniform layer, the effect of the present invention due to having two layers may be impaired, which is not preferable. . Therefore, the solvent used for coating the upper heat-sensitive layer is preferably a poor solvent for the alkali-soluble polymer contained in the lower layer.

The concentration of the above-mentioned components (total solid content including additives) in the solvent when applying each layer is preferably 1-5.
It is 0% by weight. The coating amount (solid content) of the heat-sensitive layer on the support obtained after coating and drying varies depending on the use, but the heat-sensitive layer is 0.05 to 1.0 g / m ² , and the lower layer is 0.3 to 3 It is preferably 0.0 g / m ² . When the heat-sensitive layer is less than 0.05 g / m ^2, the image forming property is lowered, sensitivity exceeds 1.0 g / m ² comes out is ON can be reduced. Further, if the coating amount of the lower layer is out of the above range, the image forming property tends to be deteriorated when the amount is too small or too large. In addition, the total of the above two layers is 0.
Is preferably 5~3.0g / m ^2, film properties is reduced and the amount of coating is less than 0.5g / m ^2, 3.0
If it exceeds g / m ² , the sensitivity tends to decrease. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate.

Various methods can be used for coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating and roll coating. You can In the heat-sensitive layer of the present invention, a surfactant for improving the coatability, for example, JP-A-62-1709.
Fluorine-based surfactants such as those described in Japanese Patent Publication No. 50 can be added. The preferable addition amount is 0.01 to 1% by weight, and more preferably 0.05 to 0.5% by weight based on the total solid content of the lower layer or the upper heat-sensitive layer.

[Support] The support of the lithographic printing plate precursor used in the present invention includes a dimensionally stable plate-like material having necessary strength and durability, such as paper, Paper laminated with plastic (eg, 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.), a paper laminated with the above-mentioned metal, or vapor-deposited, or a plastic film.

As the support of the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, and may be a plastic film in which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese,
Examples include copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of foreign elements in the alloy is at most 10% by weight.

Aluminum which is particularly preferred in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in terms of refining technology, and thus may contain slightly different elements. As described above, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and publicly known aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.1 mm to 0.4 mm.
It is 2 mm to 0.3 mm.

Prior to roughening the aluminum plate, if desired, a degreasing treatment for removing the rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. Roughening treatment of the surface of the aluminum plate,
Various methods are used, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of chemically selectively dissolving the surface. As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. Further, as an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution.
Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can be used. The thus roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to anodizing treatment if desired to enhance the water retention and abrasion 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, and generally, sulfuric acid, phosphoric acid,
Oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodic oxidation vary depending on the electrolyte used and cannot be unconditionally specified. Generally, however, the concentration of the electrolyte is 1 to 80 wt% solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A. / Dm ² , voltage 1 to 100 V, electrolysis time 10 seconds to 5 minutes are suitable. If the amount of the anodic oxide film is less than 1.0 g / m ² , printing durability may be insufficient, or the non-image area of the planographic printing plate may be easily scratched.
So-called "scratch stains" tend to occur in which ink adheres to the scratched portion during printing. After being subjected to anodizing treatment, the aluminum surface is optionally subjected to hydrophilic treatment. Examples of the hydrophilic treatment used in the present invention include US Pat.
No. 14,066, No. 3,181,461, No. 3,2
There are alkali metal silicate (eg sodium silicate aqueous solution) methods such as those disclosed in 80,734 and 3,902,734. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolyzed. In addition, potassium fluorozirconate disclosed in JP-B-36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272 are disclosed. The method of treating with polyvinylphosphonic acid as described above is used.

The lithographic printing plate precursor applied to the present invention is
Although at least two layers of an upper heat-sensitive layer and a lower layer are laminated on the support, an undercoat layer may be provided between the support and the lower layer, if necessary. Various organic compounds are used as the undercoat layer component, and examples thereof include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent. , Naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, etc. Organic phosphoric acid, phenylphosphinic acid which may have a substituent, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

This organic undercoat layer can be provided by the following method. That is, water or methanol, ethanol,
A method in which the above organic compound is dissolved in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is applied onto an aluminum plate and dried, and an organic solvent such as water or methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is applied. Is a method in which an aluminum plate is immersed in a solution in which the above organic compound is dissolved to adsorb the above compound, followed by washing with water or the like and drying to provide an organic undercoat layer. In the former method, a solution having a concentration of 0.005 to 10% by weight of the above organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight.
And the immersion temperature is 20 to 90 ° C., preferably 25 to 5
The temperature is 0 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this is ammonia,
The pH can be adjusted within the range of 1 to 12 by using a basic substance such as triethylamine and potassium hydroxide, or an acidic substance such as hydrochloric acid and phosphoric acid. Further, a yellow dye may be added to improve the tone reproducibility of the image recording material. The coating amount of the organic undercoat layer is appropriately ² to 200 mg / m ² , and preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

The positive-working lithographic printing plate precursor prepared as described above is imagewise exposed in accordance with the plate-making method of the present invention, and then developed. As a light source of actinic rays used for image exposure, for example, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp,
There are carbon arc lamps. As radiation, electron beam,
There are X-rays, ion beams, far infrared rays, and the like. Also g line,
i-line, Deep-UV light, and high-density energy beam (laser beam) are also used. Examples of the laser beam include helium / neon laser, argon laser, krypton laser, helium / cadmium laser, and KrF excimer laser. In the present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser and a semiconductor laser are particularly preferable.

In the method of the present invention, the developing solution and the replenishing solution used for the development of the lithographic printing plate precursor are composed mainly of a conventionally known organic compound having a buffering action and a base, and are substantially oxidized. It is necessary to use an alkaline developer that does not contain silicon. In the present invention, such a developing solution is hereinafter referred to as "non-silicate developing solution". Here, "substantially" means allowing the presence of inevitable impurities and a trace amount of silicon dioxide as a by-product. In the image forming method of the present invention, by applying such a non-silicate developer in the development step of the lithographic printing plate precursor, the effect of suppressing the occurrence of scratches is expressed, and there is no defect in the image area, which is good. A lithographic printing plate can be obtained. The pH of the alkaline aqueous solution is particularly 12.5-1.
3.5 is preferable.

The "non-silicate developer" used in the plate-making method of the present invention is composed mainly of an organic compound having a buffering action and a base as described above. Examples of the organic compound having a buffering action include saccharides (especially those represented by the general formula (I) or (II)) described in JP-A-8-220775 as a compound having a buffering action, and oximes (especially General formula (III)), phenols (particularly represented by general formula (IV)), fluorinated alcohols (particularly represented by general formula (V)) and the like. Among the compounds represented by the general formulas (I) to (V), preferable compounds are those represented by the general formula (I) or (II).
And a phenol represented by the general formula (V), more preferably a non-reducing sugar such as saccharose or a sulfosalicylic acid among the saccharides represented by the general formula (I) or (II). is there. The non-reducing sugars include trehalose-type oligosaccharides having reducing groups bound to each other, glycosides having reducing groups of saccharides bound to non-saccharides, sugar alcohols obtained by hydrogenating and reducing saccharides, and the like. In the present invention, any of these is preferably used.

Examples of the trehalose type oligosaccharides include saccharose and trehalose, and examples of the glycosides include alkyl glycosides, phenol glycosides, mustard oil glycosides and the like. Examples of the sugar alcohol include, for example, D, L-arabite, rebit, xylit, D, L-sorbit, D, L-annitol,
Examples thereof include D, L-idit, D, L-talit, zuricit, and alodulcit. Furthermore, maltitol obtained by hydrogenation of a disaccharide, a reduced form (reduced starch syrup) obtained by hydrogenation of an oligosaccharide, and the like can be preferably mentioned.

Of the above, sugar alcohol and saccharose are preferable as the non-reducing sugar, and among them, D-sorbit, sucrose and reduced starch syrup are more preferable because they have a buffering action in an appropriate pH range. These non-reducing sugars may be used alone or in combination of two or more, and the proportion in the developer is preferably 0.1 to 30% by weight,
1 to 20% by weight is more preferable.

An alkaline agent as a base may be appropriately selected and combined from the conventionally known compounds as the organic compound having a buffering action. Examples of the alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate,
Triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate,
Inorganic alkaline agents such as potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, ammonium borate, potassium citrate, tripotassium citrate,
Sodium citrate and the like can be mentioned. Furthermore, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanol. Preference is also given to organic alkali agents such as neuramis, ethyleneimine, ethylenediamine, pyridine and the like. These alkaline agents may be used alone or in combination of two or more kinds.

Of these, sodium hydroxide and potassium hydroxide are preferred. The reason is that the pH can be adjusted in a wide pH range by adjusting the addition amount to the non-reducing sugar. Also, trisodium phosphate,
Tripotassium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they have a buffering effect by themselves.

Furthermore, in the case of developing using an automatic processor, an aqueous solution (replenisher) having a higher alkali strength than the developer.
It is known that a large amount of the lithographic printing plate precursor can be processed by replacing the developing solution in the developing tank for a long time without adding the developing solution to the developing solution. Also in the present invention, this replenishment system is preferably applied. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution, if necessary, for the purpose of promoting or suppressing the developing property, dispersing the development residue and enhancing the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, in the developing solution and the replenishing solution, if necessary, hydroquinone, resorcin,
It is also possible to add a reducing agent such as sodium salt or potassium salt of an inorganic acid such as sulfurous acid or bisulfite, and further an organic carboxylic acid, an antifoaming agent or a water softener.

The printing plate developed using the above-mentioned developing solution and replenishing solution is post-treated with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As the post-treatment when the image recording material of the present invention is used as a printing plate, various combinations of these treatments can be used.

In recent years, in the plate making / printing industry, automatic developing machines for printing plates have been widely used in order to rationalize and standardize the plate making work. This automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for conveying a printing plate, each processing liquid tank and a spraying device, which conveys an exposed printing plate horizontally while pumping it up with each pump. The processing liquid is sprayed from a spray nozzle for development processing. Further, recently, a method has also been 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 for processing. In such automatic processing, it is possible to perform processing while supplementing each processing solution with a replenishing solution according to the processing amount, operating time, and the like. Further, a so-called disposable processing method of processing with a substantially unused processing liquid can be applied.

In the lithographic printing plate precursor according to the invention, imagewise exposure, development, washing and / or rinsing and / or
Alternatively, when the planographic printing plate obtained by gumming has an unnecessary image portion (for example, a film edge mark of the original image film), the unnecessary image portion is erased. For such erasing, for example, an erasing liquid as described in Japanese Patent Publication No. 2-13293 is applied to an unnecessary image portion,
It is preferable to carry out a process of leaving it as it is for a predetermined time and then washing it with water. However, as described in JP-A-59-174842, the unnecessary rays are irradiated with an actinic ray guided by an optical fiber and then developed. The method to do is also available.

The lithographic printing plate obtained by the plate-making method of the present invention as described above can be subjected to a printing step after applying a desensitizing gum, if desired. When it is desired to make a printing plate, a burning process is performed. When the planographic printing plate is burned, Japanese Patent Publication Nos. 61-2518 and 55-280 should be used before burning.
62, JP-A-62-31859 and JP-A-61-1596.
It is preferable to treat with a leveling solution as described in JP-A-55. As the method, with a sponge or absorbent cotton soaked with the surface-adjusting solution, it is applied on the lithographic printing plate, or by immersing the printing plate in a vat filled with the surface-adjusting solution, Application by an automatic coater is applied. Further, making the coating amount uniform with a squeegee or a squeegee roller after coating gives more preferable results.

The amount of the surface conditioning solution applied is generally 0.03 to 0.8.
g / m ² (dry weight) is suitable. The planographic printing plate coated with the surface-adjusting solution is dried if necessary, and then a burning processor (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: “BP-130”).
0 ") and so on. The heating temperature and time in this case depend on the types of components forming the image,
The range of 180 to 300 ° C. and the range of 1 to 20 minutes are preferable.

The lithographic printing plate which has been subjected to the burning treatment can be subjected to conventional treatments such as washing with water and gumming, if necessary, but a surface-adjusting solution containing a water-soluble polymer compound or the like. When is used, so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such treatment is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0072]

EXAMPLES The present invention will be described below with reference to examples.
The scope of the invention is not limited to these examples. [Preparation of support substrate] Si: 0.06 mass%, Fe:
0.30% by mass, Cu: 0.014% by mass, Mn: 0.
001 mass%, Mg: 0.001 mass%, Zn: 0.0
01% by mass, Ti: 0.03% by mass, balance A
A molten metal was prepared by using 1 and aluminum alloy of unavoidable impurities, subjected to molten metal treatment and filtration, and then had a thickness of 500 m.
A m ingot having a width of 1200 mm was prepared by a DC casting method. After scraping the surface with an average thickness of 10 mm with a chamfer,
It was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., a rolled plate having a thickness of 2.7 mm was formed using a hot rolling mill. Further, heat treatment is performed for 500 times using a continuous annealing machine.
After being performed at 0 ° C., cold rolling was performed to finish an aluminum plate having a thickness of 0.24 mm. This aluminum plate has a width of 1030
After the thickness was adjusted to mm, the following surface treatment was continuously performed.

(A) Mechanical roughening treatment A roller-shaped nylon brush that rotates while supplying a suspension of an abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to the surface of an aluminum plate. Was used to mechanically roughen the surface. 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 bristle length was 50 mm, and the bristle diameter was 0.3 mm. The nylon brush was prepared by forming holes in a stainless steel cylinder having a diameter of 300 mm and densely implanting the bristles. 3 rotating brushes
I used this book. Two support rollers under the brush (φ200
mm) was 300 mm. As for the brush roller, the load of the drive motor that rotates the brush is 7 kW against the load before the brush roller is pressed against the aluminum plate.
Hold down until it becomes positive. 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 alkaline agent The aluminum plate after the mechanical roughening treatment obtained above was sprayed at a caustic soda concentration of 2.6% by mass, an aluminum ion concentration of 6.5% by mass and a temperature of 70 ° C. An etching treatment was performed to melt the aluminum plate at 6 g / m ² .
Then, washing with water was performed by spraying.

(C) Desmutting treatment Desmutting treatment was carried out by spraying with a 1% by weight nitric acid aqueous solution (containing 0.5% by weight of aluminum ion) at a temperature of 30 ° C., and thereafter, washing with water was carried out by spraying. As the nitric acid aqueous solution used for the desmut, a waste liquid from the step of electrochemically roughening the surface of the nitric acid aqueous solution using an alternating current was used.

(D) Electrochemical surface roughening treatment Electrochemical surface roughening treatment was continuously carried out using an alternating voltage of 60 Hz. The electrolytic solution at this time is 10 g / L of nitric acid.
The solution was an aqueous solution (containing 5 g / L of aluminum ion and 0.007 mass% of ammonium ion) at a temperature of 80 ° C. The current density is 30 A / dm ² at the peak value of the current, and the quantity of electricity is 130 C as the total quantity of electricity when the aluminum plate is the anode.
/ Dm ² . 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, washing with water was performed by spraying.

(E) Alkali etching treatment An aluminum plate was subjected to a spray etching treatment at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass to give 0.20 g of the aluminum plate.
/ M ² melted and the smut component mainly composed of aluminum hydroxide generated when electrochemical roughening was performed using the alternating current in the previous stage was removed, and the edge portion of the generated pit was melted. To smooth the edges. afterwards,
It was washed with water by spraying.

(F) Desmutting treatment Desmutting treatment was carried out by spraying with an aqueous 25% by weight sulfuric acid solution (containing 0.5% by weight of aluminum ion) at a temperature of 60 ° C., and then washing with water was carried out by spraying.

(G) Anodizing treatment Anodizing device of the two-stage power feeding electrolytic treatment method (first and second electrolysis section lengths each 6 m, first and second power feed section lengths 3 m, first and second power feed electrode lengths 2 each) .4 m) was used to perform anodizing treatment. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis sections. The electrolytes are all sulfuric acid concentration 1
70 g / liter (0.5% by mass of aluminum ion)
Including. ) And the temperature was 43 ° C. Then, washing with water was performed by spraying. Final oxide film amount is 2.7 g / m ²
Met.

(H) Alkali Metal Silicate Treatment By immersing the aluminum support obtained by anodizing treatment in a treated layer of a 1% by mass aqueous solution of No. 3 sodium silicate at a temperature of 30 ° C. for 10 seconds. Alkali metal silicate treatment (silicate treatment) was performed. Then, washing with water was performed by spraying.

(I) Formation of Undercoat Layer An undercoat solution having the following composition was coated on the aluminum metal silicate-treated aluminum support obtained as described above, 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 .

[0082] <Undercoat composition>   ・ The following compound 0.3g   ・ Methanol 100g   ・ Water 1g

[0083]

[Chemical 1]

[Example 1] The following coating solution for lower layer was applied to the obtained substrate so that the coating amount was 0.85 g / m ^2, and then PERFECT OVEN P, manufactured by TABAI.
Wind Control is set to 7 in H200 and dried at 140 ° C. for 50 seconds, and then the heat-sensitive layer coating solution is applied at a coating amount of 0.15 g / m ² and then 1
It was dried at 20 ° C. for 1 minute to obtain a lithographic printing plate precursor 1.

[0085] (Coating liquid for lower layer) ・ N- (4-aminosulfonylphenyl) methacrylamide /     Acrylonitrile / methyl methacrylate     (36/34/30: weight average molecular weight 50,000, acid value 2.65) 2.133 g ・ Cyanine dye A (the following structure) 0.109 g * 4,4'-bishydroxyphenyl sulfone 0.126 g ・ Tetrahydrophthalic anhydride 0.190g -P-toluenesulfonic acid 0.008 g ・ 3-Methoxy-4-diazodiphenylamine     Hexafluorophosphate 0.030 g ・ Ethyl violet counter ion     Replaced with 6-hydroxynaphthalene sulfone 0.10 g ・ Megafuck F176, manufactured by Dainippon Ink and Machinery Co., Ltd.   (Coating surface condition improving fluorinated surfactant) 0.035g ・ Methyl ethyl ketone 25.38 g ・ 1-Methoxy-2-propanol 13.0 g -Γ-butyrolactone 13.2 g

[0086]

[Chemical 2]

[0087] [Coating liquid for upper heat-sensitive layer] -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight     4500, containing 0.8% by weight of unreacted cresol) 0.2846 g ・ Cyanine dye A (the above structure) 0.075 g ・ Megafuck F176 (20%), manufactured by Dainippon Ink and Chemicals, Inc.         (Surface-improving surfactant) 0.022g ・ MegaFac MCF-312 (30%), manufactured by Dainippon Ink and Chemicals, Inc.]         (Image forming improved fluorinated surfactant) 0.120 g ・ Methyl ethyl ketone 15.1 g ・ 1-Methoxy-2-propanol 7.7 g

Further, the following experiment was conducted to measure the surface hardness. On the smooth aluminum surface which has not been treated as a lithographic printing plate precursor support, the photosensitive layer coating liquid used in the lithographic printing plate precursor 1 is used as a photosensitive film in a lower layer of 0.85 g / m ² and an upper heat sensitive layer. The coating was sequentially applied at 0.15 g / m ² and dried at 140 ° C. for 50 seconds, and then the hardness of the upper heat-sensitive layer under an ultra small load was measured using a triboscope manufactured by Heiditron. Using a diamond indenter with an apex angle of 90 degrees, the indentation depth under an indentation load of 30 μN was 66 nm, and the hardness was calculated to be 0.64 GPa by the same calculation method as in JP-A-10-326406.

[Example 2] A lithographic printing plate precursor 2 was obtained in the same manner as in Example 1 except that the cyanine dye A in the coating solution for the upper heat-sensitive layer of Example 1 was changed to 0.050 g. Further, the surface hardness was evaluated in the same manner as in Example 1, and the hardness was 0.53 GPa.
Was calculated.

Comparative Example 1 A lithographic printing plate precursor 3 was obtained in the same manner as in Example 1, except that the cyanine dye A in the coating solution for the upper heat-sensitive layer of Example 1 was changed to 0.030 g. Further, the surface hardness was evaluated in the same manner as in Example 1, and the hardness was 0.45 GPa.
Was calculated.

[Example 3] The cyanine dye A in the coating solution for the upper heat-sensitive layer of Example 1 was changed to 0.033 g, and tetrabutylammonium hexafluoroborate was newly added.
A lithographic printing plate precursor 4 was obtained in the same manner as in Example 1 except that 03 g was added. Further, the surface hardness was evaluated in the same manner as in Example 1, and the hardness was calculated to be 0.57 GPa.

Example 4 A lithographic printing plate was prepared in the same manner as in Example 1 except that 0.033 g of cyanine dye A and 0.03 g of azodiphenylamine hexafluorophosphate were added to the coating solution for the upper heat-sensitive layer of Example 1. I got the original version 5.
Further, the surface hardness was evaluated in the same manner as in Example 1, and the hardness was 0.6
It was calculated to be 2 GPa.

[Evaluation of lithographic printing plate precursor] (Scratch resistance test) Obtained lithographic printing plate precursor of the present invention
HEIDO 1, 2 and 4,5, the lithographic printing plate precursor 3 of the comparative example
Using a scratch tester manufactured by N company, diamond (tip diameter 1.0m
m) is applied with a load to scratch the plate, and then developed with Fuji Photo Film Co., Ltd. developer DT-1 (diluted to have an electric conductivity of 45 mS / cm), and the load at which scratches are visible is displayed. did. It is evaluated that the larger the value is, the more excellent the scratch resistance is. The developing solution (DT-1) is a non-silicate developing solution whose main component is sorbitol. The results of the scratch resistance evaluation are shown in Table 1.

[0094]

[Table 1]

As is clear from Table 1, the lithographic printing plate precursors 1, 2, 4 and 5 of the present invention have higher hardness and good scratch resistance than the lithographic printing plate precursor 3 of Comparative Example. showed that.
In addition, the infrared absorption dye weight% shows the compounding quantity with respect to the total solid content of the upper heat-sensitive layer composition.

[0096]

INDUSTRIAL APPLICABILITY The lithographic printing plate precursor and plate-making method of the present invention are adapted to the infrared laser recording system by forming the heat-sensitive layer into a two-layer structure and setting the surface hardness of the upper heat-sensitive layer to 0.50 GPa or more. It is possible to obtain a positive-working lithographic printing plate precursor for direct plate making which is excellent in scratch resistance, that is, in which generation of defects due to scratches in the image area is suppressed.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H025 AA04 AB03 AC08 AD03 CB52                       CC11 DA36 DA40 FA10 FA17                 2H096 AA06 BA09 CA03 CA20 EA04                       EA23 GA08

Claims (5)

[Claims] 1. An upper heat-sensitive layer comprising a hydrophilic support, a lower layer containing a water-insoluble and alkali-soluble resin, and a water-insoluble and alkali-soluble resin and an infrared absorbing dye, the solubility of which is increased in an alkaline aqueous solution by heating. And
The upper heat-sensitive layer has a surface hardness of 0.5.
A positive-working lithographic printing plate precursor, which is 0 GPa or more. 2. The surface hardness of the upper heat-sensitive layer is 0.60 G.
The positive planographic printing plate precursor according to claim 1, which has a Pa value of at least Pa. 3. An infrared absorbing dye is added to the upper thermosensitive layer in an amount of 10%.
The content is in the range of weight% or more.
Alternatively, the positive planographic printing plate precursor as described in 2 above. 4. The positive-working lithographic printing plate precursor as claimed in claim 1, wherein the upper heat-sensitive layer contains an onium-type dissolution inhibitor. 5. An upper heat-sensitive layer containing a water-insoluble and alkali-soluble resin on a hydrophilic support, and an upper heat-sensitive layer containing a water-insoluble and alkali-soluble resin and an infrared absorbing dye and having an increased solubility in an alkaline aqueous solution by heating. And the surface hardness of the upper heat-sensitive layer is 0.50 GP.
A method for making a positive type lithographic printing plate precursor, which comprises exposing the lithographic printing plate precursor a or more described above to imagewise and then developing with an alkali developer.