JPH11194485A - Original plate for planographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original plate for positive planographic printing which may be directly made from digital data of a computer, etc., by an IR laser and does not require special processing, such as wet development processing and rubbing, after image writing. SOLUTION: This original plate for planographic printing has an image recording layer contg. at least an IR absorbent and a high-polymer compd. which contains >=2 structural units A described below in the polymer main chain and in which both ends of the structural units A are sealed by end sealing groups bonded by any one bond selected from the group consisting of an ester bond, ether bond and urethane bond on a hydrophilic base. The structural units A are -CHR<1> -O-, where R<1> denotes hydrogen, 1-3C alkyl group or halogen atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called direct plate making positive type lithographic printing plate precursor capable of making a plate directly from digital data by ablating an image recording layer with an infrared laser.

[0002]

2. Description of the Related Art Heretofore, as a system for directly making a plate from digitized data of a computer or the like, an electrophotographic system, a photopolymerization system for exposing using a laser emitting blue or green light, a silver salt-sensitive system, or the like. There have been proposed ones laminated on a conductive resin, ones based on a silver salt diffusion transfer method, and the like. However, in the case of using the electrophotographic method, an image forming process such as charging, exposure, and development is complicated, and the apparatus is complicated and large. In the case of the photopolymerization system, since it is a highly sensitive plate material, it is difficult to handle it in a bright room. The method using a silver salt has disadvantages such as complicated processing such as development and silver contained in the processing waste liquid. Also requires post-heating and subsequent development processing, which complicates the processing.

In the production of these printing plates, after the exposure process, a wet developing process for removing the image recording layer provided on the surface of the support in an image-like manner, and washing the developed printing plates with water are provided. A post-treatment step of washing with water or treating with a rinse solution containing a surfactant, gum arabic, or a desensitizing solution containing a starch derivative is included.

[0004] On the other hand, in the plate making and printing industries in recent years, environmental problems have arisen due to the alkaline developer waste liquid. In addition, plate making work is being streamlined,
There is a demand for a printing original plate that does not require the above-described complicated wet development processing and can be used for printing as it is after exposure.

In recent years, the development of lasers has been remarkable. Particularly, solid-state lasers and semiconductor lasers that emit infrared rays having a wavelength of 760 nm to 1200 nm (hereinafter sometimes referred to as “IR”) have high output and small size. It is easily available. These lasers are very useful as a recording light source when making a plate directly from digital data of a computer or the like. However, many photosensitive recording materials that are practically useful have a photosensitive wavelength in the visible light range of 760 nm or less, and therefore cannot record images with these infrared lasers. Therefore, a material that can be recorded by an infrared laser is desired.

Some lithographic printing systems using an image forming material that can be made with an infrared laser, utilize polymer ablation, and do not require a wet development process have already been disclosed. For example, it is hydrophobic,
In addition, EP 649,374 discloses a printing plate technology in which a heat-sensitive layer composed of a thermally depolymerizable polymer whose main chain is cut by the action of heat, a light-to-heat conversion material, and an ink repellent substance is formed.
No. However, in this case, the printing plate preparation required a developing operation for removing the ink repellent layer composed of the silicone layer.

JP-A-6-317899 describes a negative printing plate for recording a heat-sensitive layer containing a cationic polymer having pendant ammonium and an IR absorber with a laser. However, this requires tap water development. In other words, although no wet development processing is required after image writing, rubbing or other special processing is required, which is not sufficient from the viewpoint of simplification of processing.

A lithographic printing system which can make a plate using an infrared laser and does not require any special processing such as wet development or rubbing after writing an image. A lithographic printing system forms an image by decomposing a polymer surface with a laser. A laser printing plate is disclosed. For example, US Pat. No. 5,605,780 describes a lithographic printing plate in which an anodized aluminum support is provided with an image-forming material containing an infrared absorber and a cyanoacrylate polymer. In this case, in terms of sensitivity and contamination of the printed matter, it was considerably improved, but in practice, the sensitivity was further increased.
There is a need for a material that does not easily cause dirt.

[0009] EP 0 649 374 mentions polyacetal compounds as an example of polymers which can be ablated in combination with infrared absorbers. However, this technical content relates to so-called waterless printing, in which a polyacetal compound and a silicone layer are combined, the silicone layer is used as an ink repellent layer, and the portion where the silicone layer is removed by IR laser exposure is used as an ink receiving layer. Yes, it does not relate to the usual so-called printing with water, printing with ink and water. With "waterless", a normal printing machine and printing ink cannot be used. Therefore, a planographic printing plate with "water" was desired. In fact, when several polymers described in this document were applied to a hydrophilic support and evaluated for printability, ablation did not completely occur near the hydrophilic support, and decomposed products remained on the hydrophilic substrate. As a result, the exposed portion becomes dirty.

[0010]

Accordingly, an object of the present invention is to make plate making directly from digital data of a computer or the like by using an infrared laser, and does not require any special processing such as wet development or rubbing after image writing. An object of the present invention is to provide a positive type lithographic printing plate precursor. It is a further object of the present invention to provide a positive type lithographic printing plate precursor having high sensitivity and free from stains.

[0011]

Means for Solving the Problems As a result of various studies on polymers capable of being ablated, the present inventors have found that a polymer having a specific polyacetal structure can be recorded by an infrared laser or the like by combining with a polymer having an IR dye. It has been found that in a so-called printing method with water, in which printing is performed with the ink and water, a printed matter free of stains can be obtained without particularly troublesome processing. That is, the present invention comprises, on a hydrophilic support, at least 1) an infrared absorber, and 2) two or more structural units A shown below in a polymer main chain;
And a polymer compound in which both ends of the structural unit A are blocked by a terminal blocking group bonded by any one bond selected from the group consisting of an ester bond, an ether bond, and a urethane bond. A lithographic printing original plate having a recording layer. - structural unit A: -CHR of ¹ -O- wherein, R ¹ represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a halogen atom.

Although the reason why the above-mentioned polymer compound is particularly effective among many ablatable polymers is not clear, when this polymer is combined with an IR absorber, it is completely decomposed by IR exposure, and Is likely to be scattered by heat due to its low molecular weight, and no polymer residue remains on the surface of the hydrophilic support, so that excellent printing performance can be obtained. In addition, by using an IR absorber, a positive type lithographic printing plate precursor having high sensitivity can be obtained, and an image can be formed with a less expensive laser device.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component of the present invention will be sequentially described in detail. First, a polymer compound which is a characteristic component of the present invention will be described.

[Polymer Compound] The polymer compound used in the present invention contains two or more of the following structural units A in the polymer main chain. - structural unit A: -CHR of ¹ -O- wherein, R ¹ represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a halogen atom, (F, Cl, Br, etc.).

In the formula, when R ¹ represents an alkyl group,
It may have a substituent. The substituent has 1 carbon atom
An alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms such as a phenyl group, an alkoxy group having 1 to 10 carbon atoms,
And halogen atoms such as F, Cl, and Br, such as an acyl group having 10 to 10, an alkoxy group having 2 to 14 carbon atoms, and a carbonyl group having 1 to 15 carbon atoms. When there are a plurality of substituents for R ^1, the substituents may be bonded to each other to form a ring.

Further, the polymer compound used in the present invention is:
An end capping group in which both ends of the structural unit A are bonded by any one bond selected from the group consisting of an ester bond, an ether bond and a urethane bond (end c
Applied). In addition, both ends of the structural unit A of the polymer compound used in the present invention may be blocked by the same terminal blocking group or may be different. The terminal capping group is preferably acid-decomposable.
Preferred examples of the acid-decomposable terminal capping group include the following.

Examples of the terminal blocking group for blocking the terminal by an ester bond include a formyl group and a t-butyloxycarbonate group. Examples of a terminal capping group for capping a terminal by an ether bond include an alkyl group such as a t-butyl group, a methoxymethyl group, a benzyloxymethyl group, a methoxybenzyl group, a substituted alkyl group such as a tetrahydropyranyl group, a trimethylsilyl group, Dimethyl-t-
And silyl groups such as butylsilyl group. As a terminal blocking group for blocking the terminal by a urethane bond,
_{-CO (NH-C 6 H 5} ), - CO (NH-CH 3),
—CO (NH-nC ₄ H ₉ ) and the like.

The molecular weight of the polymer compound used in the present invention is 500 to 1,000 as a weight average molecular weight.
It is preferably about 000, and more preferably about 1,000.
It is about 0 to 200,000. If it is less than 500, it is not preferable because the film-forming property is deteriorated.

Examples of the high molecular compound useful in the present invention include formaldehyde, alkyl aldehyde, halogenated aldehyde, phthalaldehyde, and the like.
Polymers such as aromatic dialdehydes such as o-formylphenylacetaldehyde, and copolymers thereof, which are end-capped as described above.

Specific examples of the polymer compound used in the present invention are shown below. The present invention is not limited to these specific examples.

[0021]

Embedded image

[0022]

Embedded image

In the above compounds, n is selected from a number that can fall within the above-mentioned range of the molecular weight of the polymer compound as a whole, and is preferably 5 or more.

The polymer compound used in the present invention can be synthesized by a general method described in literature as a method for synthesizing a polyacetal compound or the like. Such literature includes “Synthetic Polymer IV,” Shunsuke Murahashi et al., P.
176 Asakura Shoten (1975), and the literature described therein, for example, Brit P.S. 965,42
5 (1964), Masanobu Nishii et al., Annual Report of Japanese Society for Radiation Polymer Research, Vol. 6, 181 (1964); Dando et al., J. Polymer. Sci. 60, S-24.
(1962). USP2,
No. 998,409 (Dupont).

The proportion of the polymer compound used in the present invention in the image recording layer is preferably 30% of the total solid content of the image recording layer.
９９99.99% by weight, preferably 50-99.9% by weight.
%, More preferably 80 to 99% by weight.

[Infrared absorber] The infrared absorber used in the present invention is a dye or pigment that effectively absorbs infrared rays having a wavelength of 760 nm to 1200 nm. Preferably, it is a dye or a pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm. 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. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes Is mentioned.

Preferred dyes are described in, for example, JP-A-58-1983.
125246, JP-A-59-84356, JP-A-5-84356
Cyanine dyes described in JP-A-9-202829 and JP-A-60-78787;
JP-A-58-181690, JP-A-58-194
No. 595, etc .;
Naphthoquinone dyes described in JP-A-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. JP-A-58-112
792 and the cyanine dyes described in British Patent No. 434,875, and the like.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also preferable. Pyrylium salt, JP-A-57-142645
No. (U.S. Pat. No. 4,327,169) described in JP-A-58-181051, JP-A-58-220143, JP-A-59-41363, and JP-A-59-41363.
Nos. -84248, 59-84249, 59-14
Pyrylium compounds described in JP-A Nos. 6063 and 59-146061, cyanine dyes described in JP-A-59-216146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and the like. Fairness 5-13
Pyrylium compounds disclosed in JP-A-514 and JP-A-5-19702 are also preferably used. Another preferred example of the dye is U.S. Pat. No. 4,756,993.
Near-infrared absorbing dyes described in the specification as formulas (I) and (II) can be mentioned. Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes.

The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook, “Latest Pigment Handbook” (edited by Japan Pigment Technical Association, 1977)
Annual Publication), “Latest Pigment Application Technology” (CMC Publishing, 1986)
Pigments described in "Printing Ink Technology", CMC Publishing, 1984). Examples of the type of the pigment include a black pigment, a yellow pigment, an orange pigment, a brown pigment, a red pigment, a violet pigment, a blue pigment, a green pigment, a fluorescent pigment, a metal powder pigment, and a polymer-bound pigment. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Preferred among these pigments is carbon black.

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 Soap" (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, it is not preferable in terms of stability of the dispersion in the coating solution for the image recording layer, and when it exceeds 10 μm, it is not preferable in terms of uniformity of the image recording layer. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

These dyes or pigments are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 50% by weight, based on the total solid content of the image recording layer.
1 to 10% by weight, particularly preferably 0.5 to 1 in the case of dyes
0% by weight, and in the case of a pigment, particularly preferably 1.0 to 10% by weight, can be added to the image recording layer. If the amount of the pigment or the dye is less than 0.01% by weight, the sensitivity is lowered, and if it exceeds 50% by weight, the non-image portion is stained during printing.

[Other Components] In the present invention, the above two components are essential. However, various compounds other than these may be added as necessary.

In the present invention, in order to decompose the polymer compound to form an image, it is desirable to add an acid generator as an acid generating means for accelerating the decomposition reaction.
However, the polymer compound itself is decomposed by heat, and the decomposition proceeds in a chain reaction. In particular, an acid generator is indispensable because an image can be formed without using another acid generator in combination. is not. In the present invention, a known compound that generates an acid by the action of light or heat can be selected and used as the acid generator.

For example, SISchlesinger, Photogr.Sci.E
ng., 18,387 (1974), TSBal etal, Polymer, 21,423 (198
0) etc., U.S. Pat.
Nos. 9,055 and 4,069,056;
Ammonium salts described in Nos. 40 and 140, DCNecker
etal, Macromolecules, 17,2468 (1984), CSWen etal, T
eh, Proc.Conf.Rad.Curing ASIA, p478 Tokyo, Oct (1988)
U.S. Pat. Nos. 4,069,055 and 4,069,
No. 056, etc., phosphonium salts, JVCrivello eta
l, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng.New
s, Nov. 28, p31 (1988), EP 104,143,
U.S. Patent Nos. 339,049 and 410,201,
JP-A-2-150,848, JP-A-2-296,51
Iodonium salts described in No. 4, etc., JVCrivello etal, Po
lymer J. 17,73 (1985), JVCrivello et al. J. Org.Che
m., 43, 3055 (1978), WRWatt et al, J. Polymer Sci., Pol
ymer Chem. Ed., 22, 1789 (1984), JVCrivello etal, Po
lymer Bull., 14,279 (1985), JVCrivello etal, Macrom
olecules, 14 (5), 1141 (1981), JVCrivello et al, J. Po.
lymer Sci., Polymer Chem. Ed., 17,2877 (1979), EP 370,693, U.S. Pat.
No. 233,567 and EP 297,443.
No. 297,442, U.S. Pat. No. 4,933,37.
Nos. 7, 410,201, 339,049, 4,760,013, 4,734,444, 2,833,827 and Dokoku Patent No. 2,904,626.
Nos. 3,604,580, 3,604,581, etc., JVCrivello et al, Macrom
olecules, 10 (6), 1307 (1977), JVCrivello et al, J. Po
selenonium salts described in lymer Sci., Polymer Chem. Ed., 17, 1047 (1979), etc., CSWen et al., Teh, Proc. Conf. Rad. C
onium salts such as arsonium salts described in uring ASIA, p478 Tokyo, Oct (1988), etc.

US Pat. No. 3,905,815, JP-B-46-4605, JP-A-48-36281, JP-A-55-32070, JP-A-60-239736, and JP-A-61-169835. No., JP-A-61-169837
JP-A-62-258241, JP-A-62-2124
No. 01, JP-A-63-70243, JP-A-63-29
No. 8339, K. Meier et.
al, J. Rad. Curing, 13 (4), 26 (1986), TPGill et al, Inor
g.Chem., 19,3007 (1980), D.Astruc, Acc.Chem.Res., 19
(12), 377 (1896), and organometallic / organic halides described in JP-A-2-161445, S. Hayase et al., J. Poly.
mer Sci., 25,753 (1987), E.Reichmanis et al, J.Pholyme
r Sci., Polymer Chem. Ed., 23, 1 (1985), QQZhu et al.
J. Photochem., 36, 85, 39, 317 (1987), B. Amit etal, Tetra
hedron Lett., (24) 2205 (1973), DHR Barton et al, JC
hem Soc., 3571 (1965), PMCollins et al., J. Chem. Soc.,
PerkinI, 1695 (1975), M. Rudinstein et al, Tetrahedron
Lett., (17), 1445 (1975), JWWalker et al., J. Am. Chem. S
oc., 110, 7170 (1988), SCBusman et al., J. Imaging Tech
nol., 11 (4), 191 (1985), HMHoulihan et al, Macormolec
ules, 21, 2001 (1988), PM Collins et al., J. Chem. Soc., C
hem.Commun., 532 (1972), S.Hayase etal, Macromolecule
s, 18, 1799 (1985), E. Reichmanis et al., J. Electrochem. S
oc., Solid State Sci. Technol., 130 (6), FMHoulihan e
tal, Macromolcules, 21, 2001 (1988),

European Patent Nos. 0290,750 and 04
No. 6,083, No. 156,535, No. 271,851
No. 0,388,343, U.S. Pat.
Nos. 710 and 4,181,531, JP-A-60-19
No. 8538, JP-A-53-133022 and the like.
A photoacid generator having a nitrobenzyl-type protecting group, M.TUNO
OKA etal, Polymer Preprints Japan, 35 (8), G. Berner e
tal, J.Rad.Curing, 13 (4), WJMijs etal, Coating Techn
ol., 55 (697), 45 (1983), Akzo, H. Adachi et al, Polymer P
reprints, Japan, 37 (3), European Patent No. 0199,672
Nos. 84515, 199,672 and 044
Nos. 115 and 0101,122; U.S. Pat.
8,564, 4,371,605, 4,43
1,774, JP-A-64-18143, JP-A-2-
No. 245756, Japanese Patent Application No. 3-140109, etc., compounds which generate sulfonic acid by photodecomposition represented by iminosulfonates, etc., disulfone compounds described in JP-A-61-166544 and the like; O-Naphthoquinonediazide-4-sulfonic acid halide described in JP-A-50-36209 (U.S. Pat. No. 3,969,118);
And o-naphthoquinonediazide compounds described in No. 2444 (British Patent No. 2038801) or Japanese Patent Publication No. 1-1935.

Further, in addition to these, Japanese Patent Application No. 9-26878.
And sulfonic acid esters which generate an acid by heat described in Japanese Patent Application Nos. 9-89451 and 9-85328 can be used.

As other additives, dyes having a large absorption in the visible light region can be used as colorants for images. 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 Industries, Ltd.),
Victoria Pure Blue, Crystal Violet (C
I42555), methyl violet (CI4253)
5), ethyl violet, rhodamine B (CI145
170B), malachite green (CI42000),
Examples thereof include methylene blue (CI52015) and the dyes described in JP-A-62-293247. These dyes are preferably added because the image area and the non-image area can be easily distinguished after image formation. Incidentally, the addition amount is based on the total solid content of the image recording layer.
The ratio is 0.01 to 10% by weight.

Further, a plasticizer is added to the image recording layer of the present invention, if necessary, in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic acid or methacrylic acid And a polymer. In addition to these, epoxy compounds, vinyl ethers, phenol compounds having a hydroxymethyl group described in Japanese Patent Application No. 7-18120, phenol compounds having an alkoxymethyl group, and the like may be added. Further, another polymer compound may be added to improve the strength of the coating film.

The lithographic printing plate precursor of the present invention can be usually produced by dissolving the above-mentioned components in a solvent and applying the solution on a suitable support to form an image recording layer. 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,
N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyllactone, toluene, water and the like, but are not limited thereto. Absent.

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 speaking, the lithographic printing plate precursor is preferably 0.5 to 5.0 g / m ² . Various methods can be used as the method of coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

In the image recording layer of the present invention, a surfactant for improving coating properties, for example, a surfactant described in JP-A-62-17
A fluorine-based surfactant as described in JP-A-0950 can be added. The preferred addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the total solid content of the image recording layer.

The hydrophilic support (hereinafter referred to as the hydrophilic support) used in the present invention.
Any of the conventionally known hydrophilic supports used for lithographic printing plates, which have a hydrophilic surface and can be used as the lithographic printing plate, can be used. The hydrophilic support used in the present invention is preferably a dimensionally stable plate-like material, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (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) Acetals, etc.), metal-laminated or vapor-deposited paper, plastic films, etc., as described above. For the purpose of imparting hydrophilicity and improving strength as necessary, these are known in the art. Physical or physical Processing may be performed.

Particularly preferred supports include paper, polyester film and aluminum plate. Among them, they have good dimensional stability, are relatively inexpensive, and have hydrophilicity and strength by surface treatment as required. Aluminum plates that can provide excellent surfaces are particularly preferred. Also, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in JP-B-48-18327 can be preferably used.

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 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.

In the case of a support having a metal surface, particularly an aluminum surface, a surface treatment such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate or the like, or anodizing treatment. Preferably, the treatment has been performed.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing rolling oil on the surface is performed. The surface roughening treatment of the surface of the aluminum plate is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. 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, a method combining both of them can be used as disclosed in JP-A-54-63902.

Further, an aluminum plate which has been subjected to graining treatment and then immersed in an aqueous solution of an alkali metal silicate (such as sodium silicate and potassium silicate) can be preferably used. In particular, as described in JP-B-47-5125, an aluminum plate which is anodized and then immersed in an aqueous solution of an alkali metal silicate is preferably used. Anodizing of an aluminum plate is, for example,
Anodizing an aluminum plate in an electrolytic solution containing an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid or boric acid, or an organic acid such as oxalic acid or sulfamic acid, or an aqueous solution or a non-aqueous solution of these salts alone or in combination of two or more. It is implemented by flowing a current as follows.

Electrodeposition of a silicate as described in US Pat. No. 3,658,662 is also effective. Furthermore, JP-B-46-27481, JP-A-52-586.
No. 02, JP-A-52-30503, and a surface treatment obtained by combining a support provided with electrolytic grains and the above-described anodic oxidation treatment and sodium silicate treatment are also useful. Further, those obtained by sequentially performing mechanical roughening, chemical etching, electrolytic graining, anodizing treatment, and sodium silicate treatment as described in JP-A-56-28893 are also suitable. Furthermore, after performing these treatments, a water-soluble resin such as polyvinyl sulfonic acid, a polymer and a copolymer having a sulfonic acid group in a side chain, polyacrylic acid, a water-soluble metal salt (eg, zinc borate) or yellow A primer coated with a dye, an amine salt or the like can also be suitably used. Furthermore, a sol-gel treated substrate having a functional group capable of causing an addition reaction by a radical covalently disclosed in Japanese Patent Application No. 5-304358 is also preferably used.

Other preferred examples include those in which a water-resistant hydrophilic layer is provided as a surface layer on an arbitrary support. Examples of such a surface layer include, for example, US Pat. No. 3,055,295 and JP-A-56-131.
No. 68, etc., a layer composed of an inorganic pigment and a binder, JP-A-9-80744, a hydrophilic swelling layer, and JP-A-8-80744.
No. 507727, a sol-gel film composed of titanium oxide, polyvinyl alcohol, and silicic acids.

As described above, the lithographic printing original plate of the present invention can be produced. This lithographic printing original plate is imagewise exposed by a solid-state laser and a semiconductor laser that emit infrared light having a wavelength of 760 nm to 1200 nm. In the lithographic printing plate precursor according to the present invention, the printing plate can be mounted on an offset printing machine or the like immediately after the laser irradiation to print a large number of sheets.

[0053]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples.

[0054]Examples 1-4 0.30mm thick aluminum plate (material 1050)
After washing with trichlorethylene and degreasing,
Using a 400 mesh pumicestone-water suspension
The surface was grained and washed well with water. 45 ℃
Dipped in a 25% aqueous sodium hydroxide solution for 9 seconds.
After performing washing and washing with water, 2% HNO _ThreeSoak for 20 seconds
Pickled and washed with water. The amount of etching of the grained surface at this time
Is about 3g / m^TwoMet. Next, this plate is_TwoSO_Four
Current density 15A / dm^Two3g / m^Twoof
After the DC anodic oxide film was provided, the film was washed and dried. Got
The support is referred to as support A.

Next, in the following solution [A], four kinds of solutions [A-1] to [A-4] were prepared by changing the type of the polymer compound as shown in Table 1 below. Each of the solutions was applied to the support A, and dried at 100 ° C. for 2 minutes to obtain positive planographic printing original plates [A-1] to [A-4]. The coating weight after drying was 1.5 g / m ² . (Composition of solution [A])-High molecular compound (described in Table 1 below) 1.0 g-Infrared absorbent (NK-3508, manufactured by Japan Color Sensitive Pigment Research Institute) 0.15 g-Victoria Dye in which the counter ion of pure blue BOH was converted to 1-naphthalene-sulfonic acid 0.05 g Megafac F-177 (a fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 0.03 g Methyl ethyl ketone 20 g 7 g of methyl alcohol

The obtained positive type lithographic printing plate precursor [A-1]
To [A-4] is converted to Y emitting infrared light having a wavelength of 1064 nm.
Exposure with an AG laser (output 750 mW, scanning speed 2 m
/ Sec. ). After the exposure, printing was performed on a Heidel KOR-D machine without any special processing. At this time, whether or not the non-image portion of the printed matter was stained was observed, and the number of printings was confirmed. The results are shown in Table 1 below. In each case, 50,000 or more good prints with no stain on the non-image area were obtained.

Comparative Examples 1 to 3 In the solution [A] used in Examples 1 to 3,
R dye was not added (Comparative Example 1), and the polymer compound was polymethyl methacrylate (Medium Molec).
ull Weight, Aldrich, EP064
No. 9374) (Comparative Example 2), and a product using lipophilic polyethylene terephthalate (film thickness 180 μm) as a support (Comparative Example 3).
Other than the above, positive type lithographic printing original plates [B-1] to [B-1] were prepared in the same manner as in Examples 1 to 3, and a test was performed in the same manner as in Examples 1 to 3. . The results are shown in Table 2 below. In all cases, stains occurred in the non-image area, and good printed matter could not be obtained.

[0058]

[Table 1]

Examples 5 to 8 In the following solution [B], four kinds of solutions [A-5] to [A] were prepared by changing the type of the polymer compound as shown in Table 2 below.
-8] was prepared. Each of the solutions was applied to a support A, and dried at 100 ° C. for 2 minutes to obtain positive planographic printing original plates [A-5] to [A-8]. The coating weight after drying was 1.5 g / m ² .

(Composition of Solution [B]) 3 g of high molecular compound (as shown in Table 2 below) 0.15 g of infrared absorber (IR125, manufactured by Wako Pure Chemical) Acid generator (diphenyliodonium anthraquinone sulfone) Acid salt) 0.15 g ・ methyl ethyl ketone 9 g ・ γ-butyrolactone 6 g

The obtained positive type lithographic printing plate precursor [A-5]
To [A-8] were exposed with a semiconductor laser emitting infrared light having a wavelength of 840 nm (output: 360 mW, scanning speed: 2.8).
m / sec. ). After the exposure, whether an image was formed was observed with a microscope (500 times).も の indicates that the polymer layer was completely ablated and the support was exposed, and X indicates that the polymer layer was not completely ablated and the polymer remained even a little. The results are shown in Table 2 below. In each case, the polymer layer was completely ablated and the support was exposed.

[0062]

[Table 2]

[0063]

According to the present invention, an infrared laser
Plates can be directly made from digital data from a computer or the like, and a positive type lithographic printing plate precursor that does not require special processing such as wet development or rubbing after image writing can be provided. Further, according to the present invention, the sensitivity is high,
In addition, it is possible to provide a positive type lithographic printing original plate free from stains.

Claims (2)

[Claims] 1. A hydrophilic support, comprising at least 1) an infrared absorber and 2) two or more structural units A shown below in a polymer main chain,
And a polymer compound in which both ends of the structural unit A are blocked by a terminal blocking group bonded by any one bond selected from the group consisting of an ester bond, an ether bond, and a urethane bond. A lithographic printing plate precursor having a recording layer. - structural unit A: -CHR of ¹ -O- wherein, R ¹ represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a halogen atom. 2. The lithographic printing plate precursor according to claim 1, wherein the terminal capping group is acid-decomposable.