JP2002357897A - Original plate for planographic printing plate and processing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive type original plate for a planographic printing plate for an IR laser excellent in both scuffing resistance and sensitivity and capable of direct plate making particularly from digital signals of a computer or the like and to provide a processing method for the original plate. SOLUTION: In the multilayer original plate for a planographic printing plate obtained by disposing an alkali-soluble resin-containing layer and a positive type recording layer containing an IR absorbent and having solubility in an alkaline aqueous solution increased by exposure with infrared laser light in order on a support, the positive type recording layer contains a specified polyethylene glycol compound. The original plate is imagewise exposed and developed with an alkaline developing solution containing an organic compound having the action of a pH buffer and a base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor and a method of processing the same, and more particularly to a positive type lithographic printing plate precursor for an infrared laser for so-called direct plate making which can make a plate directly from a digital signal of a computer or the like. More specifically, the present invention relates to a lithographic printing plate precursor excellent in both scratch resistance and sensitivity, and a method of treating the same.

[0002]

2. Description of the Related Art In recent years, lasers have been remarkably developed.
2. Description of the Related Art Semiconductor lasers are easily available in small size with high output. These lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like.

[0003] Positive type lithographic printing plate materials for infrared lasers are:
An essential component is an alkaline aqueous solution-soluble binder resin and an IR dye or the like that absorbs light and generates heat. The IR dye or the like dissolves in the unexposed area (image area) by interaction with the binder resin. In the exposed area (non-image area), the interaction between the IR dye etc. and the binder resin weakens in the exposed area (non-image area) and dissolves in the alkaline developer to form a lithographic printing plate. I do.

However, in such a positive type lithographic printing plate material for infrared laser, the solubility 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. However, there is a problem that the sensitivity is low, and that excessive development or poor development is likely to occur due to fluctuations in use conditions.
In addition, the surface condition is liable to fluctuate, such as fine scratches, due to touching the surface during handling, etc., but even if such fine scratches or slight surface fluctuations occur, the solubility is improved. As a result, the unexposed portion (image portion) dissolves during development to form scratch marks, which causes a problem of deterioration in printing durability and poor adhesion.

[0005] Such a problem stems from an essential difference in the plate making mechanism between a positive planographic printing plate material for infrared laser and a positive planographic printing plate material made by UV exposure. That is, in a positive lithographic printing plate material made by UV exposure, a binder resin soluble in an aqueous alkaline solution and an onium salt or a quinonediazide compound are essential components. In the image area), not only does it act as a dissolution inhibitor due to the interaction with the binder resin, but in the exposed area (non-image area), it is decomposed by light to generate acid and acts as a dissolution accelerator. Things. On the other hand, the IR dye or the like in the positive type lithographic printing plate material for an infrared laser only functions as a dissolution inhibitor in an unexposed portion (image portion) and does not promote dissolution in an exposed portion (non-image portion). . Therefore, in order to obtain a difference in solubility between the unexposed portion and the exposed portion in the infrared laser positive lithographic printing plate material, a binder resin having high solubility in an alkali developing solution must be used in advance as a binder resin. Not get
There are problems that the scratch resistance is poor and the state before development becomes unstable.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the above-mentioned prior art and to make plate making directly from a digital signal of a positive type for an infrared laser, particularly a computer, which is excellent in both scratch resistance and sensitivity. An object of the present invention is to provide a lithographic printing plate precursor for so-called direct plate making and a processing method therefor.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that the recording layer has a multilayer structure, and when an infrared absorbing agent and a polyethylene glycol compound are added to the upper layer of the multilayer structure, the scratch resistance becomes poor. And sensitivity were found to be compatible, and the present invention was completed.

That is, the present invention is as follows. (1) A multilayer lithographic printing plate comprising an alkali-soluble resin-containing layer provided on a support, and a positive-type recording layer containing an infrared absorber and having increased solubility in an alkaline aqueous solution upon exposure to an infrared laser. A lithographic printing plate precursor, wherein the positive recording layer contains a compound having the following structure.

R ¹ -｛-O- (R ³ -O-) _m -R ² ｝ _n

[0010] (R ¹ is a polyhydric alcohol residue or a polyhydric phenol residue, R ² is a hydrogen atom, an alkyl group which may have a substituent C ₁ ~ _25, an alkenyl group, an alkynyl group,
An alkylloyl group, an aryl group or an aryloyl group, R ³
Represents an alkylene residue which may have a substituent. m
Is an arbitrary integer, and n is an integer of 1 or more and 4 or less. )

(2) In the compound having the above structure, m is an integer of 10 or more on average.
The lithographic printing plate precursor described. (3) In the compound having the above structure, R ² and R ³ are each independently a group composed of at least one selected from carbon, oxygen and hydrogen. Lithographic printing plate precursor. (4) The lithographic printing plate precursor as described in (1) above, wherein the binder contained in the positive recording layer is a novolak resin. (5) The lithographic printing plate precursor as described in (1) above, wherein the alkali-soluble resin-containing layer contains an onium salt.

(6) An alkali-soluble resin-containing layer is provided on a support, and a positive-type recording layer containing an infrared absorbent and a compound having the following structure and having increased solubility in an alkaline aqueous solution upon exposure to infrared laser is provided thereon. A method for processing a lithographic printing plate precursor, comprising subjecting the provided multilayer lithographic printing plate precursor to image exposure and developing with an alkaline developer containing a pH buffering organic compound and a base.

R ¹ -｛-O- (R ³ -O-) _m -R ² ｝ _n

[0014] (R ¹ is a polyhydric alcohol residue or a polyhydric phenol residue, R ² is a hydrogen atom, an alkyl group which may have a substituent C ₁ ~ _25, an alkenyl group, an alkynyl group,
An alkylloyl group, an aryl group or an aryloyl group, R ³
Represents an alkylene residue which may have a substituent. m
Is an arbitrary integer, and n is an integer of 1 or more and 4 or less. )

The present inventors have conducted intensive studies and have found that when a polyethylene glycol compound is added to the recording layer, the inhibition (dissolution inhibition) of the recording layer is improved, and the scratch resistance is also improved. Obtained knowledge. However, when a polyethylene glycol compound is simply added to the recording layer, the scratch resistance is improved, but the sensitivity is lowered. This was considered to be due to the fact that in the single-layer type recording layer, the thermal energy converted by the infrared absorber escaped to a support such as aluminum having high thermal conductivity. Therefore, in the present invention, an alkali-soluble resin-containing layer is provided in a multilayer structure on a support, and an infrared absorber and a polyethylene glycol compound having the above structure are contained in the upper layer to provide a lower layer with heat absorption by a support such as aluminum. It is considered that heat generation due to exposure can be effectively used to cancel the interaction between the polyethylene glycol and the upper heat-sensitive layer, and the decrease in sensitivity can be suppressed while improving the scratch resistance.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the invention has a two-layer positive recording layer, and the heat-sensitive layer located on the upper side contains an infrared absorbing dye and a polyethylene glycol compound.

The positive recording layer of the lithographic printing plate precursor according to the present invention will be described below. The positive recording layer in the invention has a laminated structure, and has a heat-sensitive layer (also referred to as an upper layer) provided at a position close to the surface (exposed surface) and an alkali-soluble resin provided at a side close to the support. And a lower layer containing All of these layers need to contain a water-insoluble and alkali-soluble resin, and the upper heat-sensitive layer needs to contain an infrared absorbing dye and a polyethylene glycol compound having the following structure.

R ¹ -｛-O- (R ³ -O-) _m -R ² ｝ _n

[0019] (R ¹ is a polyhydric alcohol residue or a polyhydric phenol residue, R ² is a hydrogen atom, an alkyl group which may have a substituent C ₁ ~ _25, an alkenyl group, an alkynyl group, alkyloyl group, An aryl group or an aryloyl group, R ³ represents an alkylene residue which may have a substituent, m is preferably an integer of 10 or more on average, and n is an integer of 1 or more and 4 or less.)

Hereinafter, each component of the lithographic printing plate precursor of the present invention will be described. The heat-sensitive layer (also referred to as the upper layer) located above the lithographic printing plate precursor according to the invention contains a polyethylene glycol compound that inhibits the solubility of the layer in order to increase the scratch resistance. (Polyethylene glycol compound) Examples of polyethylene glycol compounds include polyethylene glycols,
Polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers,
Polyethylene glycol alkyl aryl ethers,
Polypropylene glycol alkyl aryl ethers, polyethylene glycol glycerin ester, polypropylene glycol glycerin ester, polyethylene sorbitol ester, polypropylene glycol sorbitol ester, polyethylene glycol fatty acid ester, polypropylene glycol fatty acid ester, polyethylene glycolated ethylenediamine, polypropylene glycolized Ethylenediamines,
Examples include polyethylene glycolated diethylene triamines and polypropylene glycolated diethylene triamines.

Specific examples of these are polyethylene glycol 1000, polyethylene glycol 2000,
Polyethylene glycol 4000, polyethylene glycol 10,000, polyethylene glycol 20,000,
Polyethylene glycol 5000, polyethylene glycol 100,000, polyethylene glycol 20,000
0, polyethylene glycol 500000, polypropylene glycol 1500, polypropylene glycol 3
000, polypropylene glycol 4000, polyethylene glycol methyl ether, polyethylene glycol ethyl ether, polyethylene glycol phenyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol diphenyl ether, polyethylene glycol lauryl ether, polyethylene glycol dilauryl ether, polyethylene glycol nonyl ether,
Polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol distearyl ether, polyethylene glycol behenyl ether, polyethylene glycol dibehenyl ether, polypropylene glycol methyl ether, polypropylene glycol ethyl ether, polypropylene glycol phenyl ether, polypropylene glycol dimethyl ether, polypropylene glycol diethyl ether , Polypropylene glycol diphenyl ether, polypropylene glycol lauryl ether, polypropylene glycol dilauryl ether, polypropylene glycol nonyl ether, polyethylene glycol acetyl ester, polyethylene glycol diacetyl ester, Ethylene glycol benzoate, polyethylene glycol lauryl ester, polyethylene glycol dilauryl ester, polyethylene glycol nonylate, polyethylene glycol cetylate, polyethylene glycol stearoyl ester, polyethylene glycol distearoyl ester, polyethylene glycol behenate, polyethylene glycol dibehenate Acid ester, polypropylene glycol acetyl ester, polypropylene glycol diacetyl ester, polypropylene glycol benzoate, polypropylene glycol dibenzoate, polypropylene glycol laurate, polypropylene glycol dilaurate,
Polypropylene glycol nonylate, polyethylene glycol glycerin ether, polypropylene glycol glycerin ether, polyethylene glycol sorbitol ether, polypropylene glycol sorbitol ether, polyethylene glycolated ethylene diamine, polypropylene glycolated ethylene diamine, polyethylene glycolated diethylene triamine,
Examples include polypropylene glycolated diethylenetriamine and polyethylene glycolated pentamethylenehexamine.

The amount of the polyethylene glycol compound to be added is 0.1 to 40% in solid content, preferably 0.2 to 20%.
%. If the content is less than 0.1%, no inhibition (solubility inhibition) effect is exhibited, and if the content is more than 40%, polyethylene glycol, which could not interact with the heat-sensitive layer binder, promotes the penetration of the developing solution. Deteriorates.

[Infrared absorbing dye] The infrared absorbing dye contained in the upper layer of the lithographic printing plate precursor of the present invention is not particularly limited as long as it is a dye that absorbs infrared light and generates heat. Various known dyes can be used.

As the infrared absorbing dye according to the present invention, commercially available dyes and known dyes described in literatures (for example, "Dye Handbook" edited by The Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dye, metal complex salt azo dye, pyrazolone azo dye, anthraquinone dye, phthalocyanine dye, carbonium dye, quinone imine dye,
Dyes such as methine dye and cyanine dye are exemplified. 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 lasers that emit infrared light or near-infrared light.

As such a dye that absorbs infrared light or near infrared light, for example, JP-A-58-125246.
JP-A-59-84356, JP-A-59-2028
29, JP-A-60-78787, JP-A-58-173696 and JP-A-5-173696.
Methine dyes described in JP-A-8-181690 and JP-A-58-194595;
JP-A-58-224793, JP-A-59-481
No. 87, JP-A-59-73996, JP-A-60-52
No. 940, naphthoquinone dyes described in JP-A-60-63744, squarylium dyes described in JP-A-58-112792, British Patent 43
And the cyanine dyes described in U.S. Pat.

Further, US Pat.
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (U.S. Pat. No. 4,327,169), a trimethinethiapyrylium salt described in JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363
Nos. 59-84248, 59-84249, 59-146063, and 59-146061 and pyrylium compounds described in JP-A-59-2161.
No. 46, a cyanine dye disclosed in U.S. Pat. No. 4,283,4.
No. 75, pentamethine thiopyrylium salt and the like, and Japanese Patent Publication Nos. 5-135514 and 5-19702, pyrylium compounds and the like, as commercial products, Epolin III-178 by Eporin, Epoli
Ght III-130, Epollight III-125 and the like are particularly preferably used. Another particularly preferred 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 heat-sensitive layer but also to the lower layer. By adding an infrared absorbing dye to the lower layer, the lower layer can also function as a heat-sensitive layer. When an infrared absorbing dye is added to the lower layer, the same substance as in the upper heat-sensitive layer may be used, or a different substance may be used. Further, these infrared absorbing dyes may be added to the same layer as other components, or another layer may be provided and added thereto. If it is a separate layer, it is desirable to add it to a layer adjacent to the heat-sensitive layer. Further, the dye and the alkali-soluble resin described later are preferably contained in the same layer, but may be in different layers. The addition amount is 0.01 to 50% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.5 to 10% by weight, based on the total solid content of the thermosensitive layer. be able to. If the amount of the dye is less than 0.01% by weight, the sensitivity becomes low, and if it exceeds 50% by weight, the uniformity of the thermosensitive layer is lost and the durability of the thermosensitive layer is deteriorated.

[Alkali-Soluble Polymer] Next, the upper and lower layers of the lithographic printing plate precursor according to the present invention are provided with a water-insoluble and alkali-water-soluble polymer compound (hereinafter referred to as an alkali-soluble polymer or an alkali-soluble resin as appropriate). ). The alkali-soluble polymer includes a homopolymer containing an acidic group in a main chain and / or a side chain in the polymer, a copolymer thereof, or a mixture thereof. Therefore, the upper layer and the lower layer according to the present invention have the property of dissolving when contacted with an alkaline developer. The alkali-soluble polymer used for the lower layer and the upper layer of the present invention is not particularly limited as long as it is a conventionally known one, but (1) a phenolic hydroxyl group, (2) a sulfonamide group, and (3) an active imide group. It is preferable that the polymer compound has any one of the above functional groups in the molecule. For example, the following are exemplified, but the present invention is not limited thereto.

(1) Examples of the high molecular 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-, or m- / p-mixture). Novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. As the high molecular compound having a phenolic hydroxyl group, a high molecular compound having a phenolic hydroxyl group in a side chain is preferably used. As the high molecular compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer composed of a low molecular compound having at least one unsaturated bond capable of polymerizing with the phenolic hydroxyl group may be homopolymerized, or another polymerizable monomer may be used. Examples include a polymer compound obtained by copolymerizing a monomer.

Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylate, methacrylate, 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 and the like can be suitably used. Such resins having a phenolic hydroxyl group may be used in combination of two or more. No. 4,123,279.
As described in the specification, a condensation polymer of 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, may be 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 monomer with another polymerizable monomer is used. Is mentioned. Examples of the polymerizable monomer having a sulfonamide group include a sulfonamide group having at least one hydrogen atom bonded to a nitrogen atom in one molecule, —NH—SO ₂ —.
And a polymerizable monomer composed of a low-molecular compound having at least one polymerizable unsaturated bond. Among them, a low-molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

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

As such a compound, specifically,
N- (p-toluenesulfonyl) methacrylamide, N
-(P-Toluenesulfonyl) acrylamide and the like can be suitably used.

Further, as the alkali-soluble polymer compound of the present invention, two or more of the above-mentioned polymerizable monomers having a phenolic hydroxyl group, polymerizable monomers having a sulfonamide group, and polymerizable monomers 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 two or more polymerizable monomers. When a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imide group is copolymerized with a polymerizable monomer having a phenolic hydroxyl group, the mixing weight ratio of these components is from 50:50 to 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 a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group with another polymerizable monomer. In the case of a polymer, the content of the monomer for imparting alkali solubility is preferably at least 10 mol%, more preferably at least 20 mol%. If the monomer component imparting alkali solubility is less than 10 mol%, alkali solubility tends to be insufficient, and the effect of improving development latitude may not be sufficiently achieved.

The monomer components to be copolymerized with the above-mentioned polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a 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, compounds. (M1) Acrylic esters and methacrylic 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 and glycidyl methacrylate; (M4) acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N
Acrylamide or methacrylamide such as -phenylacrylamide, N-nitrophenylacrylamide, and 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 and the like. (M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide. (M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

As the alkali 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- /
Novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins are preferred.

Further, as an alkali water-soluble polymer compound having a phenolic hydroxyl group, further, as described in US Pat. No. 4,123,279,
C3 to C3 such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin
And polycondensates of phenol and formaldehyde having an alkyl group of 8 as a substituent.

As a method of copolymerizing an alkali water-soluble polymer compound, a conventionally known graft copolymerization method,
A block copolymerization method, a random copolymerization method, or the like can be used.

In the present invention, the alkali-soluble polymer is
In the case of a homopolymer or 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 Those having a molecular weight of 500 or more are preferred. 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 degree of dispersion (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 a phenol formaldehyde resin and a cresol aldehyde resin, the weight average molecular weight is 500 to
20,000 and a number average molecular weight of 200 to 10,000
00 is preferred.

As the alkali-soluble polymer used in the lower layer, an acrylic resin can maintain good solubility of the lower layer in an alkali developing solution containing an organic compound having a buffering action and a base as main components. It is preferable from the viewpoint of image formation at the time of development. Further, a resin having a sulfoamide group is particularly preferable as the acrylic resin. Further, as the alkali-soluble polymer used in the upper layer, strong hydrogen bonding occurs in an unexposed portion, and in an exposed portion, some hydrogen bonds are easily released, so that image forming properties are improved. Therefore, a resin having a phenolic hydroxyl group is desirable. More preferably, it is a novolak resin.

Each of these alkali-soluble polymer compounds may be used alone or in combination of two or more.
It is used in an amount of 0 to 99% by weight, preferably 40 to 95% by weight, particularly preferably 50 to 90% by weight. If the addition amount of the alkali-soluble polymer is less than 30% by weight, the durability of each of the upper layer and the lower layer deteriorates, and if it exceeds 99% by weight, both sensitivity and durability are not preferable.

[Other Components] In forming the upper layer or the lower layer, in addition to the above-mentioned essential components, various additives may be further added as necessary as long as the effects of the present invention are not impaired. it can. The additive may be contained only in the lower layer, or may be contained only in the upper layer. Further, it may be contained in both layers. Hereinafter, an example of the additive will be described. For example, a thermally decomposable substance such as an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, and a substance that substantially lowers the solubility of an alkali water-soluble polymer compound when not decomposed is used in combination. This is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developing solution. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et a
1, Polymer, 21, 423 (1980), JP-A-5-158230
No. 4,069,055 diazonium salt described in U.S. Pat.
No. 4,069,056, and ammonium salts described in the specification of JP-A-3-140140, DC Necker et al, Macr.
omolecules, 17, 2468 (1984), CS Wen et al, Teh,
Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (198
8), U.S. Pat.Nos. 4,069,055 and 4,069,056, phosphonium salts described in JVCrivello et al, Macromorecule
s, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28,
p31 (1988), EP 104,143, U.S. Patent 339,04
No. 9, 410,201, JP-A-2-150848, JP-A-2-296
No. 514, an iodonium salt, JVCrivello et al,
Polymer J. 17, 73 (1985), JV Crivello et al. J.
Org.Chem., 43, 3055 (1978), WR Watt et al, J.
Polymer Sci., PolymerChem.Ed., 22, 1789 (1984),
JV Crivello et al, Polymer Bull., 14, 279 (198
5), JV Crivello et al, Macromorecules, 14 (5)
, 1141 (1981), JV Crivello et al, J. Polymer Sc
i., Polymer Chem. Ed., 17, 2877 (1979), European Patent No.
370,693, 233,567, 297,443, 297,442
Nos., U.S. Pat.Nos. 4,933,377, 3,902,114, 410,20
No. 1, No. 339,049, No. 4,760,013, No. 4,734,444, No.
2,833,827, German Patent No. 2,904,626, 3,604,580
No. 3,604,581, JV Cri
vello et al, Macromorecules, 10 (6), 1307 (1977), J.
V. Crivello et al, J. Polymer Sci., Polymer Chem.
Ed., 17, 1047 (1979).
S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p
478 Tokyo, Oct (1988). Of the onium salts, diazonium salts are particularly preferred. Particularly preferred diazonium salts include those described in JP-A-5-158230.

As the counter ion of the onium salt, tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid,
-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- Benzoyl-benzenesulfonic acid, paratoluenesulfonic acid and the like can be mentioned. Among them, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable. The onium salt may be added to either the upper layer or the lower layer, but the lower layer is preferred from the viewpoint of image forming properties.

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 can be a compound having various structures. In other words, o-quinonediazide assists the solubility of the light-sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the fact that o-quinonediazide itself changes to an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include those described in J. Am. The compounds described in "Light-Sensitive Systems" by John Coleyer (John Wiley & Sons. Inc.), pages 339-352, can be used, but are particularly suitable for reacting with various aromatic polyhydroxy compounds or aromatic amino compounds. Sulfonic acid esters or amides of quinonediazides are preferred. Also, benzoquinone (1,2) -diazidesulfonic acid chloride or naphthoquinone- (1,1) described in JP-B-43-28403.
2) esters of -diazide-5-sulfonic acid chloride with pyrogallol-acetone resin, U.S. Pat. No. 3,046,12
No. 0 and 3,188,210, esters of benzoquinone- (1,2) -diazidesulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride with phenol-formaldehyde resin. It is preferably used.

Further, esters of naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazide-
Esters of 4-sulfonic acid chloride with pyrogallol-acetone resin are likewise preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-965
No. 75, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication No.
41-11222, JP-B-45-9610, JP-B-49-17481,
U.S. Pat.Nos. 2,797,213, 3,454,400, 3,544,
No. 323, No. 3,573,917, No. 3,674,495, No. 3,78
No. 5,825, British Patent No. 1,227,602, No. 1,251,345,
No. 1,267,005, No. 1,329,888, No. 1,330,932
And German Patent No. 854,890.

The amount of the o-quinonediazide compound added is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 1 to 50% by weight, based on the total solids forming the layer.
It is in the range of 0 to 30% by weight. 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 weight, more preferably 5 to 30% by weight, particularly preferably 10 to 30% by weight. The additive of the present invention and the alkali-soluble polymer are preferably contained in the same layer.

For the purpose of enhancing the discrimination of images and the resistance to scratches on the surface, perfluoro compounds having 3 to 20 carbon atoms in the molecule as described in JP-A-2000-187318. It is preferable to use a polymer having a (meth) acrylate monomer having two or three alkyl groups as a polymerization component. Such a compound may be contained in either the upper layer or the lower layer, but more effective is to include it in the upper layer. The amount added is preferably from 0.1 to 10% by weight, more preferably from 0.5 to 5% by weight, in the upper layer material.

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

Further, the lower layer or the upper layer in the present invention may contain a compound having a low molecular weight acidic group, if necessary. Sulfonic acid, carboxylic acid,
A phosphate group can be mentioned. Among them, compounds having a sulfonic acid group are preferred. Specific examples 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 layer. The addition amount is preferably 0.05 to 5% by weight in the material forming the layer, more preferably 0.1 to 5% by weight.
1 to 3% by weight. If it is more than 5%, the solubility of each layer in the developer increases, which is not preferable.

In the present invention, various dissolution inhibitors may be contained for the purpose of adjusting the solubility of the lower layer or the upper layer. Examples of the dissolution inhibitor include JP-A-11-119418.
A disulfone compound or a sulfone compound as disclosed in JP-A No. 5-2,078 is preferably used, and as a specific example, 4,4′-bishydroxyphenyl sulfone is preferably used. Such a compound may be contained in either the lower layer or the upper layer. It is preferable that the content of each layer is 0.05 to 20% by weight in the material constituting the layer.
More preferably, it is 0.5 to 10% by weight.

For the purpose of further improving the sensitivity, cyclic acid anhydrides, phenols and organic acids can be used in combination. 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. Patent No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride, and the like. As phenols, bisphenol A, p-nitrophenol, p-nitrophenol
Ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "
-Trihydroxytriphenylmethane, 4,4 ',
3 ", 4" -tetrahydroxy-3,5,3 ', 5'-
Tetramethyltriphenylmethane and the like can be mentioned. Further, as organic acids, JP-A-60-88942 and JP-A-Hei 2
Sulfonic acids described in -96755 and the like,
There are sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters and carboxylic acids, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, 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-
Examples thereof include 1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid. The proportion of the above-mentioned 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, particularly preferably 0.1 to 15% by weight. 1 to 10% by weight.

Further, in the lower or upper layer coating solution according to the present invention, in order to broaden the stability of processing under development conditions,
JP-A-62-251740 and JP-A-3-2085
Non-ionic surfactants described in JP-A No. 14-114, JP-A No. 59-121044, JP-A No. 4-13
No. 149, an amphoteric surfactant,
A siloxane-based compound as described in EP950517 and a fluorine-containing monomer copolymer as described in JP-A-11-288093 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearic acid, and polyoxyethylene nonyl phenyl ether. Specific examples of the amphoteric surfactant include:
Alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine type (for example, trade name "Amogen K ": Manufactured by Daiichi Kogyo Co., Ltd.).

The siloxane-based compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE- made by Chisso Corporation.
224, DBE-621, DBE-712, DBP-7
32, DBP-534, manufactured by Tego, Germany, Tego G
and polyalkylene oxide-modified silicones such as LIDE100. The ratio of the nonionic surfactant and the amphoteric surfactant in the coating liquid material is 0.1%.
It is preferably from 0.5 to 15% by weight, more preferably from 0.1 to 15% by weight.
5% by weight.

In the lower layer or the thermosensitive layer in the present invention,
A printing-out agent for obtaining a visible image immediately after heating by exposure, and a dye or pigment as an image coloring agent can be added. Representative examples of the printing-out agent include a combination of a compound that releases an acid by heating upon exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, o-naphthoquinonediazide-4 described in JP-A-50-36209 and JP-A-53-8128 is disclosed.
A combination of a sulfonic acid halide and a salt-forming organic dye, and JP-A-53-36223 and JP-A-54-74728.
No. 60-3626, No. 61-143748, No. 61-151644 and No. 63-58440 in combination with the trihalomethyl compounds and salt-forming organic dyes. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear print-out images.

As a colorant for an image, other dyes can be used in addition to the above-mentioned salt-forming organic dye. 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) and the like. Also, Japanese Unexamined Patent Publication No. Sho 62-2
The dyes described in JP 93247 A are particularly preferred. These dyes are used in an amount of 0.1 to the total solid content of the printing plate material.
It can be added to the printing plate material in a proportion of from 01 to 10% by weight, preferably from 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 and the like 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 the lower layer of the lithographic printing plate precursor according to the present invention can be usually formed by dissolving the above-mentioned components in a solvent and coating the solution on a suitable support. As the solvent used herein, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate,
Examples thereof include, but are not limited to, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, and toluene. These solvents are used alone or as a mixture.

As the solvent used for coating, it is preferable to select a solvent having different solubility in the alkali-soluble polymer used in the heat-sensitive layer and the alkali-soluble polymer used in the lower layer. In other words, when a lower layer is coated and then a heat-sensitive layer as an upper layer is coated next to the lower layer, if a solvent that can dissolve the lower layer alkali-soluble polymer is used as a coating solvent for the uppermost layer, mixing at the layer interface is ignored. In an extreme case, it may not be a multilayer but a uniform single layer. As described above, when mixing occurs at the interface between two adjacent layers or when the two layers are compatible with each other and exhibit a behavior like a uniform layer, 2
The effect of the present invention due to the presence of the layer may be impaired, which is not preferred. Therefore, it is desirable that the solvent used for applying the upper heat-sensitive layer be a poor solvent for the alkali-soluble polymer contained in the lower layer. The concentration of the above components (total solids including additives) in the solvent when applying each layer is preferably 1 to 50% by weight.

The coating amount (solid content) of the upper layer and the lower layer on the support obtained after coating and drying varies depending on the use, but the upper layer is 0.05 to 1.0 g / m ² , and the lower layer is 0.1 g / m ² . It is preferably from ³ to 3.0 g / m ² . If the upper layer is less than 0.05 g / m ^2, the image forming property is lowered, sensitivity exceeds 1.0 g / m ² comes out may be reduced. If the amount of the lower layer is out of the above range, the image forming property tends to be reduced when the amount is too small or too large. In addition, the total of the two layers is 0.5 to
It is preferably 3.0 g / m ² and the coating amount is 0.5 g / m ^2.
If it is less than g / m ² , the film properties will be degraded and 3.0 g / m ²
If it exceeds, the sensitivity tends to decrease. As the amount of coating decreases, the apparent sensitivity increases, but the film properties of the upper and lower layers decrease.

Various methods can be used for the coating, such as bar coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating, and the like. Can be. In the upper layer and the lower layer in the present invention, a surfactant for improving coating properties, for example,
A fluorine-based surfactant as described in JP-A-170950 can be added. The preferred amount is
It is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the total solid content of the lower or upper layer.

[Support] As the support of the lithographic printing plate precursor used in the present invention, a dimensionally stable plate having the required strength and durability can be mentioned. Plastic (for example, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (for example,
Aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate)
Polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic film on which a metal as described above is laminated or vapor-deposited.

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

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

Anodizing treatment conditions vary depending on the electrolyte to be used, and thus cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° 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 appropriate. When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image portion of the lithographic printing plate is easily scratched,
So-called "scratch stains" in which ink adheres to scratches during printing are likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment as necessary. U.S. Pat. Nos. 2,7,7
No. 14,066, No. 3,181,461, No. 3,2
There is an alkali metal silicate (e.g., sodium silicate aqueous solution) method as disclosed in U.S. Pat. Nos. 80,734 and 3,902,734. In this method, the support is immersed or electrolytically treated with an aqueous solution of sodium silicate. Further, potassium fluoride zirconate disclosed in JP-B-36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689,272 are disclosed. A method of treating with polyvinyl phosphonic acid as described above is used.

The lithographic printing plate precursor applied to the present invention is:
At least two layers, a positive thermosensitive layer and a lower layer, are laminated on the support, and an undercoat layer can be provided between the support and the lower layer as needed. As the undercoat layer component, various organic compounds are used, for example, carboxymethyl cellulose, dextrin, gum arabic, phosphonic acids having an amino group such as 2-aminoethylphosphonic acid, and phenylphosphonic acid optionally having a substituent , Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, 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 hydroxy groups such as salts -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 a solution obtained by dissolving the above organic compound in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is applied to an aluminum plate and dried, and an organic solvent such as water or methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is used. In this method, an aluminum plate is immersed in a solution in which the above-mentioned organic compound is dissolved to adsorb the above-mentioned compound, and then washed with water or the like and dried to form an organic undercoat layer. In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight 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.
The immersion temperature is 20 to 90 ° C., preferably 25 to 5 ° C.
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 to a range of 1 to 12 with a basic substance such as triethylamine or potassium hydroxide or an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye can be added for improving the tone reproducibility of the image recording material. The coating amount of the organic undercoat layer is suitably from ² to 200 mg / m ² , and preferably from 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 is true even if it is larger than 200 mg / m ² .

The positive type lithographic printing plate precursor prepared as described above is exposed imagewise and then subjected to development processing. Examples of the light source of the actinic ray used for the image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp, and the like.
Examples of the radiation include an electron beam, an X-ray, an ion beam, and a far-infrared ray. In addition, 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 an emission wavelength in the near infrared to infrared region is preferable, and a solid-state laser and a semiconductor laser are particularly preferable.

As a developer and a replenisher used for developing the lithographic printing plate precursor according to the present invention, conventionally known developers and replenishers are used.
It is preferable to use an alkali developer containing an organic compound having a buffering action and a base as main components and containing substantially no silicon dioxide. In the present invention, such a developer is hereinafter referred to as a “non-silicate developer”. Here, “substantially” means that the presence of trace amounts of silicon dioxide as unavoidable impurities and by-products is allowed. In the development step of the lithographic printing plate precursor according to the invention, by applying the non-silicate developer, the effect of suppressing the occurrence of scratches is further improved, and a good lithographic printing plate having no defects in the image area can be obtained. it can. As the alkaline aqueous solution, particularly, pH 12.
Those having 5 to 13.5 are preferred.

The "non-silicate developer" used in the development of the lithographic printing plate precursor according to the present invention contains, as described above, an organic compound having a buffering action and a base as main components.
Examples of the organic compound having a buffering action include JP-A-8-22.
No. 0775, saccharides (particularly those represented by general formula (I) or (II)), oximes (particularly those represented by general formula (III)), and phenols described as compounds having a buffering action (Particularly those represented by the general formula (IV)) and fluorinated alcohols (particularly those represented by the general formula (V)). General formulas (I) to (V)
Among the compounds represented by the formula, preferred are saccharides represented by the general formula (I) or (II) and phenols represented by the general formula (V), and more preferably phenols represented by the general formula (I)
Or, among the saccharides represented by (II), non-reducing sugars such as saccharose or sulfosalicylic acid. Non-reducing sugars include trehalose-type oligosaccharides in which reducing groups are bonded to each other, glycosides in which the reducing groups of saccharides are bonded to non-saccharides, sugar alcohols obtained by hydrogenating and reducing saccharides, and the like.

The trehalose-type oligosaccharides include, for example, saccharose and trehalose, and the glycosides include, for example, alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, ribit, xylit, D, L-sorbit, D, L-annit,
D, L-idit, D, L-talit, zuricit, allozurcit and the like. Further, maltitol obtained by hydrogenation of a disaccharide, a reductant (reduced starch syrup) obtained by hydrogenation of an oligosaccharide, and the like can also be preferably exemplified.

Among the above, as the non-reducing sugar, sugar alcohols and saccharol are preferable, and among them, D-sorbitol, saccharose 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. The ratio of the non-reducing sugar in the developer is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight.

The above-mentioned organic compound having a buffering action can be combined with an alkali agent as a base by appropriately selecting from the conventionally known ones. 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,
And sodium citrate.

Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropylamine Organic alkali agents such as isopropanolamine, ethyleneimine, ethylenediamine, pyridine and the like can also be suitably mentioned. These alkaline agents may be used alone or in combination of two or more.

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 amount of the non-reducing sugar. Also, trisodium phosphate,
Tripotassium phosphate, sodium carbonate, potassium carbonate and the like are also preferable because they have a buffering action by themselves.

In the case of developing using an automatic developing machine, an aqueous solution having a higher alkali strength than the developing solution (replenisher)
It is known that a large amount of lithographic printing plate precursors can be processed without replacing the developing solution in the developing tank for a long period of time by adding to the developing solution. This replenishment system is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution as needed for the purpose of accelerating or suppressing the developing property, dispersing the developing residue and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, the developing solution and the replenisher may contain, if necessary, a reducing agent such as a sodium salt or a potassium salt of an inorganic acid such as hydroquinone, resorcinol, sulfurous acid, and bisulfite, and further include an organic carboxylic acid, an antifoaming agent, and a water softener. Can be added. The printing plate developed using the above developer and replenisher 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-processing of the lithographic printing plate precursor of the present invention, these processings can be used in various combinations.

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 plate making operations. This automatic developing machine generally includes a developing section and a post-processing section, and includes a device for transporting a printing plate, each processing solution tank and a spray device, and transports the exposed printing plate horizontally while pumping each plate. The developing process is performed by spraying a processing liquid from a spray nozzle. Recently, a method has been known in which a printing plate is immersed and conveyed by a submerged guide roll or the like in a processing liquid tank filled with a processing liquid to perform processing. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied.

In the lithographic printing plate precursor according to the present invention, image exposure, development, washing and / or rinsing and / or
Alternatively, if there is an unnecessary image portion (for example, a film edge mark of the original film) on the lithographic printing plate obtained by gumming, the unnecessary image portion is erased. Such erasing is performed by applying an erasing liquid as described in, for example, Japanese Patent Publication No. 2-129393 to an unnecessary image portion.
It is preferable to carry out washing by rinsing with water after leaving it for a predetermined period of time, but it is necessary to irradiate an unnecessary image area with an actinic ray guided by an optical fiber as described in JP-A-59-174842, and then develop. A method to do this is also available.

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

The coating amount of the surface conditioning liquid is generally 0.03 to 0.8.
g / m ² (dry weight) is appropriate. The lithographic printing plate to which the surface conditioning liquid has been applied is dried if necessary, and then burned (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: "BP-130").
0 "). The heating temperature and time in this case depend on the type of the component forming the image,
The temperature is preferably in the range of 180 to 300 ° C for 1 to 20 minutes.

The burned lithographic printing plate can be subjected to conventional treatments such as washing with water and gumming if necessary. However, a surface conditioning solution containing a water-soluble polymer compound or the like can be used. When is used, so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such a process is set on an offset printing machine or the like and used for printing a large number of sheets.

[0084]

Hereinafter, the present invention will be described with reference to Examples.
The scope of the present invention is not limited to these examples. [Preparation of lithographic printing plate precursors 1 to 12] [Preparation of substrate] 0.3 mm thick aluminum plate (material
1050) was degreased by washing with trichloroethylene.
After, nylon brush and 400 mesh pumice-water suspension
The surface was grained using a liquid and washed well with water. This
The plate in a 25% aqueous solution of sodium hydroxide at 45 ° C for 9 seconds
Etching by immersion, washing with water, and then 20% nitric acid
For 20 seconds and washed with water. At this time,
Etching amount is about 3g / m ^TwoMet. Next, this plate
% Sulfuric acid as electrolyte and current density 15A / dm^Two3g /
m^TwoAfter providing a direct current anodic oxide coating of
Furthermore, at 30 ° C. with a 2.5% by weight aqueous solution of sodium silicate.
Treat for 10 seconds, apply the following undercoat liquid, and coat the film at 80 ° C.
After drying for 15 seconds, a substrate was obtained. The coating amount of the coating film after drying is 1
5mg / m^TwoMet.

[Undercoat liquid]-0.3 g of the following polymer compound-100 g of methanol-1 g of water

[0086]

Embedded image

[Formation of Recording Layer 1] The following coating solution for the lower layer was applied to the obtained substrate so that the coating amount was 0.85 g / m ^2, and then PERFECT OVE manufactured by TABAI.
After drying at 140 ° C. for 50 seconds with Wind Control set to 7 with N PH200, the following heat-sensitive layer coating solution was applied so that the coating amount was 0.15 g / m ^2, and then applied at 120 ° C. for 1 hour. After drying for 1 minute, planographic printing plate precursors 1 to 7 were obtained.

[Coating solution for lower layer] N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (36/34/30: weight average molecular weight 50,000) 2.133 g 3-methoxy-4-diazo Diphenylamine 0.030 g Hexafluorophosphate • Cyanine dye A (the following structure) 0.109 g • 4,4'-Bizhydroxyphenylsulfone 0.063 g • Tetrahydrophthalic anhydride 0.190 g • p-Toluenesulfonic acid 0.008 g • Ethyl The counter ion of violet was changed to 6-hydroxynaphthalene sulfone 0.05 g ・ Fluorine surfactant (MegaFac F176, manufactured by Dainippon Ink Industries, Ltd.) 0.035 g ・ Methyl ethyl ketone 26.6 g ・ 1 -Methoxy-2-p Lopanol 13.6 g ・ γ-butyrolactone 13.8 g

[0089]

Embedded image

[Coating solution for thermosensitive layer] m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 4,500, unreacted cresol 0.8% by weight) 0.237 g, cyanine dye A ( The above structure) 0.047 g ・ Dodecyl stearate 0.060 g ・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g ・ Fluorinated surfactant (MegaFac F176, manufactured by Dainippon Ink and Chemicals, Inc.) 0 0.110 g ・ Fluorine surfactant [Megafac MCF-312 (30%), manufactured by Dainippon Ink Industries, Ltd.] 0.120 g ・ Methyl ethyl ketone 15.1 g ・ 1-Methoxy-2-propanol 7.7 g -Polyethylene glycol compound X g described in Table 1 below

[Formation of Recording Layer 2] Instead of the recording layer 1 having a two-layer structure, a coating solution for the heat-sensitive layer of the recording layer 1 was applied onto the substrate so that the coating amount was 1.00 g / m ^2. After drying at 120 ° C. for 1 minute, the lithographic printing plate precursor 8 to 1
2 was obtained.

[Evaluation of Lithographic Printing Plate Precursors] For development of the obtained lithographic printing plate precursors 1 to 12, developers DT-1 and DT-1R manufactured by Fuji Photo Film Co., Ltd. were developed in a usual manner. A scratch resistance test and sensitivity evaluation as described below were performed using the test pieces.

[Scratch Resistance Test] The obtained lithographic printing plate precursor was subjected to a rotary ablation tester (TOYO).
(SEIKI) and rubbed 20 times with Abrazelfelt CS5 under a load of 250 g. Thereafter, the film was developed using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd., charged with the above alkali developing solution, at a liquid temperature of 30 ° C. for a developing time of 12 seconds. Observed visually. The evaluation criteria for the scratch resistance were as follows, and the evaluation results are shown in Table 1 below.

：: no change in optical density △: scratch marks can be visually discriminated ：: substrate is slightly exposed ×: optical density is about ２

[Evaluation of Sensitivity] A test pattern was drawn on the obtained lithographic printing plate precursor in the form of an image by changing the exposure energy with a Trendsetter manufactured by Creo Corporation. Thereafter, a developer DT- manufactured by Fuji Photo Film Co., Ltd.
The developer was developed at 1 (diluted to an electric conductivity of 45 mS / cm), and the exposure energy at which a non-image area could be developed with this developer was measured and defined as sensitivity. The smaller the value, the higher the sensitivity. Table 1 shows the results.

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[Table 1]

From this, it can be seen that the lithographic printing plate precursor of the present invention has excellent scratch resistance and good sensitivity. On the other hand, when the heat-sensitive layer did not contain the ethylene glycol compound, the scratch resistance was low, and when the recording layer had a single-layer structure, the sensitivity was low.

[0098]

According to the lithographic printing plate precursor of the present invention and a method for treating the same, the positive recording layer contains a lower layer containing an alkali-soluble resin, an infrared absorber and a specific ethylene glycol compound, and is exposed to infrared laser. By providing an upper layer having increased solubility in an alkaline aqueous solution, both scratch resistance and sensitivity could be improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/11 503 G03F 7/11 503 7/32 7/32 (72) Inventor Akio Oda Haibara-gun, Shizuoka 4,000 Kawajiri, Yoshidacho Fujisha Shin Film Co., Ltd. F-term (reference) 2H025 AA01 AA13 AB03 AC01 AC08 AD03 BE00 CB29 CC20 DA36 FA03 FA17 2H096 AA07 BA09 BA16 BA20 CA05 EA04 GA08 GA09 GA10

Claims (6)

[Claims] 1. A multilayer lithographic plate comprising an alkali-soluble resin-containing layer provided on a support, and a positive-type recording layer containing an infrared absorber and having increased solubility in an alkaline aqueous solution upon exposure to infrared laser. In the printing plate precursor,
A lithographic printing plate precursor, wherein the positive recording layer contains a compound having the following structure. R ¹ -｛-O- (R ³ -O-) _m -R ² ｝ _n (R ¹ is a polyhydric alcohol residue or a polyhydric phenol residue,
R ² is a hydrogen atom, an alkyl group of C ₁ ~ _25, an alkenyl group,
An alkynyl group, an alkylloyl group, an aryl group or an aryloyl group, R ³ represents an alkylene residue. m is an arbitrary integer, and n is an integer of 1 or more and 4 or less. ) 2. The lithographic printing plate precursor according to claim 1, wherein in the compound having the structure, m is an integer of 10 or more on average. 3. The compound of the above structure, wherein R ² and R ³
The lithographic printing plate precursor according to claim 1, wherein each is independently a group composed of at least one selected from carbon, oxygen and hydrogen. 4. The lithographic printing plate precursor according to claim 1, wherein the binder contained in the positive recording layer is a novolak resin. 5. The lithographic printing plate precursor according to claim 1, wherein the alkali-soluble resin-containing layer contains an onium salt. 6. An alkali-soluble resin-containing layer is provided on a support, and a positive-type recording layer containing an infrared absorbent and a compound having the following structure and having increased solubility in an alkaline aqueous solution upon exposure to infrared laser is provided thereon. A method for processing a lithographic printing plate precursor, comprising: exposing an image of the multilayer lithographic printing plate precursor to an image, followed by developing with an alkaline developer containing a pH buffering organic compound and a base. R ¹ -｛-O- (R ³ -O-) _m -R ² ｝ _n (R ¹ is a polyhydric alcohol residue or a polyhydric phenol residue,
R ² is a hydrogen atom, an alkyl group of C ₁ ~ _25, an alkenyl group,
An alkynyl group, an alkylloyl group, an aryl group or an aryloyl group, R ³ represents an alkylene residue. m is an arbitrary integer, and n is an integer of 1 or more and 4 or less. )