JP2002062660A - Lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive lithographic printing original plate for IR laser for direct plate making which has a recording layer excellent in the latitude for image formation by development and excellent in the resistance against scratches. SOLUTION: The original plate is obtained by forming a positive recording layer which contains a water-insoluble and alkali-soluble resin having a siloxane structure and an absorbent for IR rays and which increases its solubility with an alkali aqueous solution by exposure to IR laser beam on a supporting body. The resin soluble with an alkali aqueous solution is prepared by introducing at least one kind of substituent having a siloxane structure (Si-O) into a well- known polymer compound soluble with an alkali aqueous 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 usable as an offset printing master, and more particularly to a positive type lithographic printing plate precursor for an infrared laser for so-called direct plate making that can be directly made from a digital signal of a computer or the like.

[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 non-exposed area (image area) by interaction with the binder resin. In the exposed area (non-image area), the generated heat weakens the interaction between the IR dye and the binder resin and dissolves in the alkaline developer to form a lithographic printing plate in the exposed area (non-image area). I do. However, in such a positive type lithographic printing plate material for an infrared laser, the solubility between the unexposed portion (image portion) in the developing solution and the solubility of the exposed portion (non-image portion) under various use conditions is determined. However, there is a problem that excessive development or poor development is likely to occur due to fluctuations in use conditions. In addition, even when the surface condition slightly changes due to touching the surface during handling, the unexposed portion (image portion) dissolves during development to form scratch marks, which causes deterioration of printing durability and poor adhesion. There was a problem.

[0004] Such a problem originates in an essential difference in a plate making mechanism between a positive type lithographic printing plate material for infrared laser and a positive type lithographic printing plate material made by UV exposure. That is, in a positive planographic printing plate material made by UV exposure, an alkaline aqueous solution-soluble binder resin and an onium salt or a quinonediazide compound are essential components. However, the onium salt or the quinonediazide compound contains an unexposed part ( In the image area), not only does it act as a dissolution inhibitor due to the interaction with the binder resin, but also in the exposed area (non-image area), it is decomposed by light to generate acid and acts as a dissolution promoter. Things. On the other hand, the IR dye and the like in the positive type lithographic printing plate material for infrared laser only act as a dissolution inhibitor in the unexposed portion (image portion) and do not promote the dissolution in the exposed portion (non-image portion). . Therefore, in the positive lithographic printing plate material for infrared laser, in order to obtain a difference in solubility between the unexposed portion and the exposed portion, a binder resin having high solubility in an alkali developing solution must be used in advance. Not get
The state before development becomes unstable.

For the purpose of increasing the solubility of an unexposed portion (image portion) in a developing solution without deteriorating the developability of an exposed portion (non-image portion), for example, Japanese Patent Application Laid-Open No. A method using a copolymer containing an addition-polymerizable fluorine-containing monomer having a fluoroaliphatic group in which a hydrogen atom on an atom is substituted with a fluorine atom in a side chain,
EP 950517 proposes a method using a siloxane-based surfactant, respectively. Although these contribute to improving the development resistance of the image portion of the recording layer to some extent, the difference in solubility between the unexposed portion and the exposed portion is so large that a sharp and good image can be formed irrespective of fluctuations in the activity of the developer. Is hardly enough.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive type lithographic printing plate precursor for an infrared laser for direct plate making, which has a recording layer which is excellent in latitude during image formation by development and has excellent scratch resistance. Is to do.

[0007]

Means for Solving the Problems As a result of intensive studies, the inventor of the present invention has found that the use of a positive photosensitive composition for an infrared laser containing an alkali-soluble resin having a siloxane structure as a recording layer allows the development latitude, The present inventors have found that a lithographic printing plate excellent in scratch resistance can be obtained, and have completed the present invention.

That is, the positive type lithographic printing plate precursor of the present invention comprises:
A positive recording layer is provided on a support, which comprises a water-insoluble and alkali-soluble resin having a siloxane structure and an infrared absorber, and has increased solubility in an alkaline aqueous solution upon exposure to infrared laser. In a preferred embodiment, the water-insoluble and alkali-soluble resin having a siloxane structure in the molecule used herein is a polymer compound having a phenolic hydroxyl group or a novolak compound.

In the present invention, by using the water-insoluble and alkali-soluble resin having the siloxane structure,
It is not clear why the resulting positive type lithographic printing plate precursor has excellent development latitude and scratch resistance, but a recording layer coating solution containing an alkali-soluble resin having a siloxane structure in the molecule is coated on a support. During drying, the siloxane structure-containing portion present in the molecule of the alkali-soluble resin is oriented on the surface of the recording layer during the drying step, and is localized to form the outermost portion. The resistance to the developer and external stress is improved, and in the non-image area, the siloxane structure does not inhibit the stability and solubility inherent in the alkali-soluble resin. It is presumed that a layer can be formed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. [Water-insoluble and alkali-soluble resin having a siloxane structure] Examples of the water-insoluble and alkali-soluble resin having a siloxane structure used in the present invention (hereinafter, appropriately referred to as a siloxane structure-containing alkali-soluble resin) include conventionally known alkali-soluble resins. Any compound may be used as long as at least one kind of partial structure having a siloxane structure is introduced into the hydrophilic polymer compound. The alkali water-soluble polymer compound is preferably a polymer compound having in the molecule any one of (1) a phenolic hydroxyl group, (2) a sulfonamide group, and (3) an active imide group,
(1) A polymer compound having a phenolic hydroxyl group in the molecule is particularly preferred, but is not limited thereto.
In the present invention, the siloxane structure refers to a structure (Si—O) in which oxygen (O) and silicon (Si) are directly bonded, and any other substituent may be bonded to an oxygen atom or a silicon atom as long as it has this structure. It may be. However, the following general formula (I)
The dialkylpolysiloxane partial structure shown by the general formula (I
It is preferable to have the disiloxane partial structure shown in I) from the viewpoint of surface orientation.

[0011]

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In the above formula, R ¹ and R ² each independently represent an alkyl group or an aryl group, and any one can be selected. From the viewpoint of surface orientation, a methyl group, an ethyl group, and a propyl group are preferred. , An isopropyl group and a phenyl group are preferred. In the general formula (I), n represents the number of repeating units of the dialkylpolysiloxane, and is preferably 20 or less from the viewpoint of not impairing the solubility of the alkali-soluble resin. R ³ , R ⁴ and R ⁵ in the general formula (II) each independently represent an alkyl group, and any one can be selected. However, from the viewpoint of surface orientation, a methyl group and an ethyl group are preferable.

As the siloxane structure-containing alkali-soluble resin, specifically, a polymerizable monomer comprising a low molecular compound having at least one substituent having a siloxane structure and at least one polymerizable unsaturated bond in one molecule ( Less than.
"Specific monomer unit"), (1) a polymerizable monomer having a phenolic hydroxyl group, (2) a polymerizable monomer having a sulfonamide group, and (3) activity, which are polymerization components of an alkali water-soluble polymer compound. A copolymer of at least one polymerizable monomer having an imide group and a copolymer of these monomers and another polymerizable monomer are exemplified. Furthermore, examples of the siloxane structure-containing alkali-soluble resin having a phenolic hydroxyl group as an alkali-soluble group include resins obtained by condensing a phenol compound and an aldehyde such as formaldehyde, such as a novolak resin. One or both of the phenol compound and the aldehyde to be condensed have a substituent having a siloxane structure.

The siloxane structure-containing alkali-soluble resin of the present invention only needs to have a specific monomer unit having a siloxane structure as shown below as a constituent unit. In order to obtain such a siloxane structure-containing alkali-soluble resin, synthesis can be performed using the following specific monomer units as a starting material, but it is not always necessary to use a specific monomer unit as a starting material. You don't have to. That is, a monomer obtained by removing a substituent having a siloxane structure from the following specific monomer unit is used as a starting material, and after homopolymerization or copolymerization, a substituent having a siloxane structure is introduced by a polymer reaction. As a result, a method of obtaining a specific alkaline water-soluble polymer having the following specific monomer unit as a constituent unit can be employed. Examples of the polymer reaction for introducing a substituent having a siloxane structure include a method of electrophilically or nucleophilically substituting an aromatic ring in an alkali-soluble polymer, and a method of hydroxyl group or amino group in an alkali-soluble polymer. Examples include a method in which a substituent is modified with an ester bond, an ether bond, a urethane bond, an amide bond, or the like. Examples of the siloxane structure-containing substituent to be introduced into the siloxane structure-containing alkali-soluble resin of the present invention include:
In forming an image forming layer by coating and drying, a substituent having a surface orientation such that the siloxane structure-containing alkali-soluble resin shifts to near the surface and is localized is preferable.

Preferred examples of such a substituent having a siloxane structure include the following, but the present invention is not limited thereto.

[0016]

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[0017]

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Next, typical examples of the polymerization component of the alkali water-soluble polymer compound into which these siloxane structure-containing units are introduced will be described. (1) Examples of the polymerizable monomer having a phenolic hydroxyl group include a polymerizable monomer composed of a phenolic hydroxyl group and a low-molecular compound having at least one polymerizable unsaturated bond. Acrylamide, methacrylamide, acrylate, methacrylate, hydroxystyrene, and the like. 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 mentioned. These monomers having a phenolic hydroxyl group may be used in combination of two or more.

(2) As a polymerizable monomer having a sulfonamide group, a sulfonamide group having at least one hydrogen atom bonded to a nitrogen atom in one molecule (-NH-SO
_2- ) and a polymerizable monomer comprising a low molecular compound having at least one polymerizable unsaturated bond. Examples thereof include an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group. Alternatively, a low molecular weight compound having a substituted sulfonylimino group is preferable. Examples of such a compound include, for example, JP-A-8-1
Compounds represented by formulas (I) to (V) described in No. 23029 can be mentioned.

(2) Specific examples of the polymerizable monomer having a sulfonamide group include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like. Can be suitably used.

(3) As the polymerizable monomer having an active imide group, those having an active imide group in a molecule described in JP-A-11-84657 are preferable.
Examples of the polymerizable monomer include an active imide group and a low-molecular compound having at least one polymerizable unsaturated bond.

(3) As the polymerizable monomer having an active imide group, specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like are preferably used. it can.

As the other polymerizable monomers, for example, the following monomers (4) to (15) can be used, but are not limited thereto. (4) Acrylic esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, and methacrylic esters. (5) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate. (6) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate. (7) 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. (8) 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.

(9) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. (10) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. (11) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone and phenyl vinyl ketone. (12) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (13) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like. (14) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, and N- (p-chlorobenzoyl) methacrylamide. (15) acrylic acid, methacrylic acid, maleic anhydride,
Unsaturated carboxylic acids such as itaconic acid;

Examples of the alkali water-soluble polymer compound having a siloxane structure include a polymerizable monomer having a siloxane structure and (1) a polymerizable monomer having a phenolic hydroxyl group because of its excellent image-forming properties upon exposure to infrared laser or the like. It is preferable that the compound has a phenolic hydroxyl group in the molecule, such as a copolymer with the above. In addition to the polymer, a siloxane structure is introduced into (1) an alkaline water-soluble polymer compound having a phenolic hydroxyl group. May be used. Examples of the alkaline water-soluble polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, and m-cresol formaldehyde resin.
Novolak resins and pyrogallol acetone resins, such as-/ p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, or m- / p-mixture) mixed formaldehyde resin, and the like.

As the alkali water-soluble polymer 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 for copolymerizing the alkali water-soluble polymer compound having a siloxane structure, conventionally known methods such as graft copolymerization, block copolymerization, and random copolymerization can be used.

The alkali water-soluble polymer compound having a siloxane structure is prepared by mixing the polymerizable monomer having a siloxane structure with another polymerizable monomer (polymerizable monomer having a silicon atom: other polymerizable monomer). Monomer) is preferably from 1:99 to 60:40, more preferably from 1:99 to 50:50. If the compounding weight ratio of the polymerizable monomer having a siloxane structure is small, the effect of improving the development latitude and scratch resistance tends to be small, because it is difficult to form the outermost part by protruding on the recording layer surface of the positive type lithographic printing plate precursor. On the contrary, if the amount is too large, the image forming property and the solubility in the coating solution tend to decrease, which is not preferable.

The alkali water-soluble polymer having a siloxane structure preferably has a weight average molecular weight of 500 or more, more preferably 1,000 to 700,000. In addition, the number average molecular weight is 500
It is more preferably at least 750 to 650,000. The degree of dispersion (weight average molecular weight / number average molecular weight) is preferably from 1.1 to 10.

The alkali water-soluble polymer compound having a siloxane structure may be used alone or in combination of two or more, and the total content thereof is 1 to 70% by weight based on the total solid content of the recording layer of the lithographic printing plate. % Is preferable, 2 to 50% by weight is more preferable, and 2 to 30% by weight is particularly preferable. If the content is less than 1% by weight, the durability tends to deteriorate, and if it exceeds 70% by weight, sensitivity and image forming properties tend to decrease, which is not preferable.

The alkali water-soluble polymer compound having a siloxane structure may be used in combination with a conventionally known alkali water-soluble polymer compound as long as the effects of the present invention are not impaired. Examples of the conventionally known alkali water-soluble polymer compound include a homopolymer of the monomers mentioned as a polymerization component of the alkali water-soluble polymer compound into which the siloxane structure is introduced, and a copolymer obtained by combining a plurality of types. . The content of this general alkali-soluble resin is 0 to 95% by weight, preferably 50 to 9% by weight, based on the siloxane structure-containing alkali-soluble resin according to the present invention.
It is 5% by weight, more preferably in the range of 70 to 90% by weight.

Hereinafter, specific examples of the alkali water-soluble polymer compound having a siloxane structure ((F-1) to (F-
6)), but the present invention is not limited to these specific examples. In the specific examples, the weight average molecular weight (M _w ) and the copolymerization ratio (molar ratio) are shown.

[0033]

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[0034]

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[Infrared absorbing agent] The infrared absorbing agent used in the present invention is not particularly limited as long as it is a substance that absorbs infrared light and generates heat, and various infrared absorbing dyes or infrared absorbing pigments are known. Pigments or dyes can be used. As pigments, commercially available pigments and Color Index (CI) Handbook, “Latest Pigment Handbook”
(Edited by Japan Pigment Technology Association, 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), and “Printing Ink Technology”, CMC Publishing, 1984) can be used.

The types of pigments include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensation azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments,
Quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dye lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.

These pigments may be used without surface treatment, or may be used after surface treatment. Methods of surface treatment include a method of surface-coating a resin or wax, a method of attaching a surfactant, and a reactive substance (for example, a silane coupling agent, an epoxy compound, or a polyisocyanate).
Can be conceived on the surface of the pigment. The above surface treatment methods are described in "Properties and Applications of Metallic Soaps" (Koshobo),
"Printing ink technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986)
It is described in.

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm.
Is preferably within the range. Pigment particle size 0.01μ
When it is less than m, the dispersion is not preferred in terms of stability in a photosensitive layer coating solution, and when it exceeds 10 μm, it is not preferred in terms of uniformity of the photosensitive layer. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Dispersers include ultrasonic dispersers, sand mills, attritors, pearl mills, super mills,
Examples include a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. For details, see “Latest Pigment Application Technology”
(CMC Publishing, 1986).

As the dye, 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. Specific examples include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, and cyanine dyes. In the present invention, among these pigments or 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 pigment absorbing infrared light or near infrared light, carbon black is preferably used. Dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246 and JP-A-59-125246.
-84356, JP-A-59-202829, JP-A-60-78787 and the like.
JP-A-58-173696, JP-A-58-18169
0, methine dyes described in JP-A-58-194595, JP-A-58-112793, and JP-A-58-112793.
Naphthoquinone dyes described in JP-A-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744 and the like; And the cyanine dyes described in British Patent No. 434,875.

As a dye, US Pat. No. 5,156,
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 pyrylium compounds disclosed in Japanese Examined Patent Application Publication Nos. 5-135514 and 5-19702, as well as commercially available products.
Epoline III-178, Epo
light III-130, Epollight III-12
5 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 pigments or dyes are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 10% by weight, and particularly preferably 0.5 to 10% by weight, based on the total solid content of the material constituting the recording layer. In the case of a pigment, it can be particularly preferably added at a ratio of 3.1 to 10% by weight. If the amount of the pigment or dye is less than 0.01% by weight, the sensitivity is lowered. If the amount exceeds 50% by weight, the uniformity of the photosensitive layer is lost and the durability of the recording layer is deteriorated. These dyes or pigments may be added to the same layer as other components, or a separate layer may be provided and added thereto. When it is a separate layer, it is desirable to add it to a layer adjacent to the layer containing the alkali-soluble resin according to the present invention. Further, the dye or pigment and the alkali-soluble resin are preferably added to the same layer, but may be different layers.

[Other Components] In forming the positive recording layer of the present invention, various additives can be used in combination, if necessary. For example, an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, and the like, which are thermally decomposable and used together with a substance that substantially lowers the solubility of the alkali water-soluble polymer compound when not decomposed. This is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developer. Examples of the onium salt include a diazonium salt, an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a selenonium salt, and an arsonium salt.

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, ammonium salt described in the specification of JP-A-3-140140, DC Necker et al, Macromolecul
es, 17, 2468 (1984), CS Wen et al, Teh, Proc. Co.
nf.Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055 and 4,069,056, phosphonium salts described in JVCrivello et al, Macromorecules, 10
(6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31.
(1988), EP 104,143, U.S. Patent 339,049
No. 410,201, JP-A-2-150848, JP-A-2-2-2965
Iodonium salt described in No. 14, JVCrivello et al, P
olymer J. 17, 73 (1985), JV Crivello et al. J.
Org.Chem., 43, 3055 (1978), WR Watt et al, J. P.
olymer Sci., Polymer Chem. 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 Sci.,
Polymer Chem. Ed., 17, 2877 (1979), European Patent No. 37
0,693, 233,567, 297,443, 297,442
Nos. 4,933,377, 3,902,114, 410,
No. 201, No. 339,049, No. 4,760,013, No. 4,734,444
No. 2,833,827, German Patent No. 2,904,626, No. 3,60
Nos. 4,580 and 3,604,581, sulfonium salts described in J.
V. Crivello et al, Macromorecules, 10 (6), 1307 (19
77), JV Crivello et al, J. Polymer Sci., Polyme
r Selenonium salt described in Chem. Ed., 17, 1047 (1979), CS Wen et al, Teh, Proc. Conf. Rad. Curing AS
IA, p478 Tokyo, Oct (1988).

In the present invention, diazonium salts are particularly preferred. Particularly preferred diazonium salts include those described in JP-A-5-158230. Examples of the counter ion of the onium salt include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid,
-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-benzoyl-benzenesulfonic acid, p-toluenesulfonic 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.

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. Preference is given to sulfonic esters or sulphonamides of quinonediazides. Also, benzoquinone (1,2)-as described in JP-B-43-28403.
Diazidesulfonic acid chloride or naphthoquinone-
Esters of (1,2) -diazide-5-sulfonic acid chloride with pyrogallol-acetone resin, U.S. Pat.
Esters of benzoquinone- (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazido-5-sulfonic acid chloride and phenol-formaldehyde resin described in 046,120 and 3,188,210 are also used. 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-48-96
No. 575, JP-A-49-38701, JP-A-48-13354, JP-B-41-11222, JP-B-45-9610, JP-B-49-17481
No. 2,797,213, No. 3,454,400, No. 3,544,323, No. 3,573,917, No. 3,674,495
No. 3,785,825; British Patent No. 1,227,602;
Nos. 1,251,345, 1,267,005, 1,329,888,
No. 1,330,932, and German Patent No. 854,890, etc. can be mentioned. o
-The addition amount of the quinonediazide compound is preferably in the range of 1 to 50% by weight, more preferably 5 to 30% by weight, particularly preferably 10 to 30% by weight, based on the total solid content of the printing plate recording layer. These compounds can be used alone, but may be used as a mixture of several kinds.

The amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight. It is preferable that the additive and the binder of the present invention are contained in the same layer.

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. Pat. 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,
Sulfonic acids, such as those described in
There are sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters, carboxylic acids, and the like.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 solid content of the recording 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. -10% by weight.

Further, in the coating solution of the recording layer in the present invention, JP-A-62-251740 and JP-A-3-208514 are used in order to widen the stability of processing under development conditions.
Non-ionic surfactants described in JP-A-59-121044, JP-A-4-13149.
Surfactant, EP described in JP
A siloxane compound as described in 950517 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 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 Dai-ichi Kogyo Co., Ltd.) and the like. As the siloxane-based compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, manufactured by Chisso Corporation.
DBE-621, DBE-712, DBP-732, D
BP-534, manufactured by Tego, Germany, Tego Glide
And polyalkylene oxide-modified silicones such as 100. The proportion of the nonionic surfactant and the amphoteric surfactant in the recording layer coating solution is 0.05 to
It is preferably 15% by weight, more preferably 0.1 to 5% by weight.

In the recording layer of 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, combinations of o-naphthoquinonediazide-4-sulfonic acid halogenide and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128,
3-36223, 54-74728, 60-3
No. 626, No. 61-143748, No. 61-1516
Nos. 44 and 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 temporal stability and give clear print-out images.

As the colorant for the image, 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 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 recording layer 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 may be added to the coating solution for the recording layer 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 recording layer of the lithographic printing plate precursor according to the present invention can be usually produced by dissolving the above-mentioned 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-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone,
Examples include, but are not limited to, toluene. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by weight. Also apply,
The coating amount (solid content) on the support obtained after drying varies depending on the application, but generally 0.5 to 5.0 g / m ² is preferred for photosensitive printing plates.

Various methods can be used for the application, such as bar coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating and the like. Can be. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate. In the photosensitive layer according to the invention, a surfactant for improving coating properties, for example, a fluorine-based surfactant described in JP-A-62-170950 can be added. A preferable addition amount is 0.01 to the total solid content of the recording layer.
To 1% by weight, more preferably 0.05 to 0.5% by weight
It is.

[Support] The support used in the present invention is a dimensionally stable plate, for example, paper or paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.). , Metal plates (eg, 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 a 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 having good dimensional stability and relatively low cost 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 the aluminum alloy 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. Aluminum which is particularly preferred 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 approximately 0.1 mm to 0.6 mm, preferably 0.15 m.
m to 0.4 mm, particularly preferably 0.2 mm to 0.3 m
m.

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 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. Further, 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.

The anodizing treatment conditions vary depending on the electrolyte used and 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 according to the present invention has a positive recording layer provided on a support. An undercoat layer may be provided between the recording layers 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 , Naphthylphosphonic acid, alkylphosphonic acid, organic phosphonic acids such as 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 planographic printing plate precursor prepared as described above is usually subjected to image exposure and 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. As radiation,
There are electron beams, X-rays, ion beams, far infrared rays, and the like. In addition, g-line, i-line, Deep-UV light, and high-density energy beam (laser beam) are also used. Laser beams include helium / neon laser, argon laser, krypton laser, helium / cadmium laser, K
rF excimer laser and the like can be mentioned. 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 the developer and replenisher for the lithographic printing plate of the present invention, conventionally known aqueous alkaline solutions can be used. For example, sodium silicate, potassium, tribasic sodium, potassium, ammonium, dibasic sodium, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, potassium Ammonium, sodium borate, potassium, ammonium, sodium hydroxide,
And inorganic alkali salts such as ammonium, potassium and lithium. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine,
Organic alkaline agents such as diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine and pyridine are also used. Can be These alkaline agents can be used alone or
Used in combination of more than one species. Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. The reason is that the developability can be adjusted by the ratio and the concentration of the silicon oxide SiO ₂ and the alkali metal oxide M ₂ O which are the components of the silicate. For example, JP-A-54-62004 discloses An alkali metal silicate described in JP-B-57-7427 is effectively used.

Further, when developing using an automatic developing machine, an aqueous solution having a higher alkali strength than the developing solution (replenisher)
It has been known that a large amount of PS plates can be processed without replacing the developing solution in the developing tank for a long 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 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, an unnecessary image portion (for example, a film of an original film) of a lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming is obtained. If there is an edge trace, the unnecessary image portion is erased. Such erasing is preferably carried out by applying an erasing liquid as described in, for example, Japanese Patent Publication No. 2-129393 to an unnecessary image portion, leaving it for a predetermined time, and then washing it with water. A method described in JP-A-59-174842, in which active light guided by an optical fiber is applied to an unnecessary image portion and then developed, can be used.

The lithographic printing plate obtained as described above can be subjected to a printing step after coating with a desensitizing gum if desired. However, when a lithographic printing plate having a higher printing durability is desired to be obtained, 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.

[0068]

Hereinafter, the present invention will be described with reference to Examples.
The scope of the present invention is not limited to these examples. [Synthesis of siloxane structure-containing alkali-soluble resin] [Synthesis Example 1: Synthesis of siloxane structure-containing alkali-soluble resin (F-1)] Cresol novolak (m / p =
60/40, Mw = 5.2 × 10 ³ ) 120 g was dissolved in methanol 400 ml, and sodium methoxide 5.4 was dissolved.
g was added and stirred for 30 minutes. The methanol was distilled off under reduced pressure, and 400 ml of tetrahydrofuran was added to replace the solvent. Epoxy type terminal reactive silicone MCR-E11
17 g (manufactured by Chisso Corporation) was added, and the mixture was heated and refluxed for 6 hours. The reaction solution was cooled to room temperature, poured into 8000 ml of water, and the separated product was collected by filtration, washed with water and dried to obtain 132 g of a siloxane structure-containing alkali-soluble resin (F-1).

[Synthesis Example 2: Synthesis of siloxane structure-containing alkali-soluble resin (F-2)] Polyparahydroxystyrene (Mw = 8.0 × 10 ³ ) 120 g was added to methanol 4
The mixture was dissolved in 00 ml, and 5.4 g of sodium methoxide was added, followed by stirring for 30 minutes. The methanol was distilled off under reduced pressure, and 400 ml of tetrahydrofuran was added to replace the solvent. Epoxy type terminal reactive silicone MCR-E11 (Co., Ltd.)
33 g (manufactured by Chisso) were added, and the mixture was heated and refluxed for 6 hours. The reaction solution was cooled to room temperature, poured into 8000 ml of water, and the separated product was collected by filtration, washed with water and dried to obtain 148 g of a siloxane structure-containing alkali-soluble resin (F-2).

[Synthesis Example 3: Synthesis of alkali-soluble resin (F-3) containing siloxane structure] Methacrylic acid 31.0
g, ethyl chloroformate 39.1 g and acetonitrile 2
The mixture was stirred while cooling in an ice-water bath. To this mixture, 36.4 g of triethylamine was dropped by a dropping funnel over about 1 hour. After completion of the dropwise addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes. The reaction mixture was added to p-aminobenzenesulfonamide 5
1.7 g was added and the mixture was stirred for 1 hour while warming to 70 ° C. After the reaction is completed, the obtained mixture is mixed with 1000 ml of water.
This water was added thereto while stirring, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to remove a precipitate, and 500 ml of water was added to the slurry to form a slurry. The slurry was filtered, and the obtained solid was dried to obtain N- (p-aminosulfonylphenyl) methacrylamide. Obtained (yield 46.9 g). N- (p-aminosulfonylphenyl) methacrylamide 5.04 g, ethyl methacrylate 1.03 g, acrylonitrile 1.1
1 g, 2.86 g of tris (trimethylsiloxy) silylpropyl methacrylate and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. 2,2 ′ as a radical polymerization initiator was added to this mixture.
0.15 g of -azobis (2,4-dimethylvaleronitrile) (trade name: "V-65", manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred under a nitrogen stream for 2 hours while maintaining the temperature at 65 ° C. To this reaction mixture, 5.04 g of N- (p-aminosulfonylphenyl) methacrylamide, 1.03 g of ethyl methacrylate, 1.11 g of acrylonitrile, 2.86 g of tris (trimethylsiloxy) silylpropyl methacrylate, N, N-dimethylacetamide A mixture of 20 g and 0.15 g of the above-mentioned "V-65" was dropped by a dropping funnel over 2 hours. After completion of the dropwise addition, the obtained mixture was further stirred at 65 ° C. for 2 hours. After the completion of the reaction, 40 g of methanol was added to the mixture, and the mixture was cooled.
After stirring the mixture for minutes, the precipitate was removed by filtration and dried, and the siloxane structure-containing alkali-soluble resin (F
-4) 19 g was obtained. The weight average molecular weight (M _w ) of each of the siloxane structure-containing alkali-soluble resins was measured by gel permeation chromatography (polystyrene standard).

[Preparation of Substrate] Aluminum having a thickness of 0.3 mm
Plate (material 1050) is washed with trichlorethylene
Degreased, nylon brush and 400 mesh pumice
Use a water suspension to grain this surface and wash well with water.
Was cleaned. Put this plate in a 25% aqueous solution of sodium hydroxide at 45 ° C.
Immerse in the solution for 9 seconds to perform etching, and after washing with water,
It was immersed in 20% nitric acid for 20 seconds and washed with water. Grain at this time
The amount of etching on the standing surface is about 3 g / m ^TwoMet. next
This plate was subjected to a current density of 15 A / dm using 7% sulfuric acid as an electrolyte.
^Two3g / m^TwoAfter providing a direct current anodic oxide coating of
Dried, and further with a 2.5% by weight aqueous solution of sodium silicate
Treat at 30 ° C for 10 seconds, apply the following undercoat liquid,
The substrate was dried at 80 ° C. for 15 seconds to obtain a substrate. Coating of coating film after drying
15mg / m^TwoMet. [Undercoat liquid]-The following compound 0.3 g-Methanol 100 g-Water 1 g

[0072]

Embedded image

(Example 1) The following photosensitive solution 1 was applied to the obtained substrate so that the coating amount was 1.0 g / m ² ,
TABAI's PERFECT OVEN PH20
At 0, WindControl was set to 7, and drying was performed at 140 ° C. for 50 seconds to obtain a lithographic printing plate precursor 1.

[Photosensitive solution 1] m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 3500, unreacted cresol 0.5% by weight) 0.427 g Alkali-soluble resin containing siloxane structure (F -1) 0.047 g Specific copolymer 1 described in JP-A-11-288093 2.37 g Cyanine dye A (the following structure) 0.155 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.03 g Tetrahydrophthalic anhydride 0.19 g A counter ion of ethyl violet converted to 6-hydroxy-β-naphthalenesulfonic acid 0.05 g Fluorosurfactant (MegaFac F176PF, manufactured by Dainippon Ink and Chemicals, Inc.) ) 0.035 g fluorinated surfactant (MegaFac MCF-312, 0.05 g para-toluenesulfonic acid 0.008 g bis-p-hydroxyphenylsulfone 0.063 g n-dodecyl stearylate 0.06 g γ-butyl lactone 13 g methyl ethyl ketone 24 g 1-methoxy-2 -11 g of propanol

[0075]

Embedded image

Example 2 The following photosensitive solution 2 was applied to the obtained substrate so that the coating amount was 1.6 g / m ² ,
Drying was performed under the same conditions as in Example 1 to obtain a lithographic printing plate precursor 2. [Photosensitive solution 2] m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, unreacted cresol 0.5% by weight) 2.00 g Alkali-soluble resin containing siloxane structure (F-1) 0.25 g octylphenol novolak (weight average molecular weight: 2500) 0.015 g cyanine dye A 0.105 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.03 g tetrahydrophthalic anhydride 0.10 g ethyl Violet counter ion converted to 6-hydroxy-β-naphthalenesulfonic acid 0.063 g Fluorosurfactant (MegaFac F176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorosurfactant (Mega FAC MCF-312, Dainippon Ink Industry Co., Ltd.) 0.13 g bis -p- hydroxyphenyl sulfone 0.08g Methyl ethyl ketone 16g 1-methoxy-2-propanol 10g

(Examples 3 and 4) In the photosensitive solution 1 of Example 1, the alkali-soluble resin having a siloxane structure shown in Table 1 below was used in place of (F-1) as the alkali-soluble resin having a siloxane structure. Except for the above, planographic printing plate precursors 3 and 4 were obtained in the same manner as in Example 1.

[0078]

[Table 1]

(Comparative Example 1) In the photosensitive solution 1 of Example 1, m, p-cresol novolak (m / p ratio = 6 /
4, weight average molecular weight 3500, unreacted cresol 0.5
Lithographic printing plate precursor 5 was obtained in the same manner as in Example 1, except that 0.474 g of the lithographic printing plate precursor was used, and the siloxane structure-containing alkali-soluble resin (F-1) was not used.

(Comparative Example 2) In the photosensitive solution 2 of Example 2, m, p-cresol novolak (m / p ratio = 6 /
4, weight average molecular weight 3500, unreacted cresol 0.5
Lithographic printing plate precursor 6 was obtained in the same manner as in Example 2 except that 2.25 g of the lithographic printing plate precursor was used without using the siloxane structure-containing alkali-soluble resin (F-1).

[Evaluation of lithographic printing plate precursor] [Scratch resistance test] The obtained lithographic printing plate precursor 1 of the present invention was obtained.
The lithographic printing plate precursors 5 and 6 of Comparative Examples 1 to 4 were rubbed 30 times with an abraser felt CS5 under a load of 250 g using a rotary ablation tester (manufactured by TOYOSEIKI). Thereafter, a developer DT-1 (diluted 1: 8) manufactured by Fuji Photo Film Co., Ltd. and a finisher FP2W manufactured by Fuji Photo Film Co., Ltd.
Using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd.
The development was performed for a development time of 12 seconds. At this time, the conductivity of the developer was 45 mS / cm.

The scratch resistance was evaluated according to the following criteria. ：: The optical density of the photosensitive film in the rubbed portion did not change at all. Δ: The optical density of the photosensitive film in the rubbed portion was slightly observed visually. ×: The optical density of the photosensitive film in the rubbed portion was small. 2 / of non-friction part
Table 2 shows the results of the scratch resistance evaluation of the samples having a rating of 3 or less.

[0083]

[Table 2]

As is clear from Table 2, the lithographic printing plate of the present invention exhibited better scratch resistance than Comparative Examples 1 and 2 which did not contain the siloxane structure-containing alkali-soluble resin.

[Evaluation of Development Latitude] The obtained planographic printing plate precursors 1 to 4 of the present invention and the planographic printing plate precursors 5 and 6 of Comparative Examples were tested with a Trendsetter made by Creo at a beam intensity of 9 W and a drum rotation speed of 150 rpm. The pattern was drawn as an image. First, the lithographic printing plate precursors 1 to 6 exposed under the above conditions were used with a developer DT-1 (diluted at 1: 9 and 1:10) manufactured by Fuji Photo Film Co., Ltd. and by Fuji Photo Film Co., Ltd. Using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd. charged with Finisher FP2W (diluted 1: 1), development was performed for 12 s while maintaining the liquid temperature at 30 ° C. The conductivity of the developer at this time was 41 mS / cm and 39 mS, respectively.
/ Cm.

The exposed portion (non-image portion) after the development was visually inspected for any stain or coloring caused by the poorly developed recording layer residual film. In the lithographic printing plate, no stain on the non-image area was observed in any of the lithographic printing plates, and good developability was exhibited. Dirt was seen in the image area. From this, lithographic printing plate precursors 1-6
It was confirmed that the developing properties of the exposed portions were almost the same.

Next, the lithographic printing plate precursors 1 to 6 exposed under the above conditions were combined with a developer DT-1 manufactured by Fuji Photo Film Co., Ltd.
(1: 6.5 dilution) and Fuji Photo Film Co., Ltd. finisher FP2W (1: 1 dilution) charged using Fuji Photo Film Co., Ltd. PS processor 900H. Temperature, development time 1
Developed for 2 s. The conductivity of the developer at this time was 52 mS /
cm. Therefore, the optical density of the unexposed portion (image portion) of the photosensitive layer of the obtained lithographic printing plate after development is visually evaluated,
Compared to the DT-1 developed with a developing solution diluted 1: 9, those in which no decrease in optical density was observed were evaluated as ○, and those in which a decrease in optical density was recognized were evaluated as x. .
Table 3 shows the results. It should be noted that the case where no concentration decrease was observed indicates that the image area was not eluted with respect to the developer having higher activity, and it can be said that the latitude with respect to the activity of the developer is wide.

[0088]

[Table 3]

As apparent from Table 3, the lithographic printing plate precursor according to the present invention has no residual film in the non-image area, has good developability, and has no reduction in the density of the image area. From this, it was found that good development latitude was exhibited.

【The invention's effect】

According to the present invention, it is possible to provide a positive type lithographic printing plate precursor for infrared laser for direct plate making which is excellent in latitude during image formation by development and excellent in scratch resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/004 505 G03F 7/004 505 // C08K 5/00 C08K 5/00 C08L 101/02 C08L 101 / 02 F-term (reference) 2H025 AA13 AB03 AC08 AD03 BE00 BE07 CB15 CB28 CB33 CB41 CB45 FA17 2H084 AA14 AE05 BB04 CC05 2H096 AA06 BA09 EA04 EA23 GA08 2H114 AA04 AA23 BA01 DA04 DA25 DA52 DA03 GA03 BC03 GA03 GA03 GA03 GA03 CC071 CP031 DA036 EE056 EQ016 EU026 FD096 FD206 GP03

Claims (3)

[Claims] 1. A positive recording layer comprising, on a support, a water-insoluble and alkali-soluble resin having a siloxane structure and an infrared absorbing agent, the solubility of which in an alkaline aqueous solution is increased by irradiation with infrared laser. Positive planographic printing plate precursor. 2. The positive planographic printing plate precursor according to claim 1, wherein the water-insoluble and alkali-soluble resin having a siloxane structure is a polymer compound having a phenolic hydroxyl group. 3. The positive lithographic printing plate precursor according to claim 1, wherein the water-insoluble and alkali-soluble resin having a siloxane structure is a novolak compound.