JP2008188995A - Plate making method of lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing plate which forms images with heat, shows good on-press developing nature, and can obtain more printed matters. <P>SOLUTION: The original plate for a lithographic printing plate is characterized by keeping a hydrophilic support overlaid with a thermal layer consisting of a microcapsule whose exterior wall is torn by heat used for image formation and containing a compound having a functional group capable of reacting by the heat with a photothermal conversion material contained in a thermal layer or its adjoining layer, wherein the hydrophilic support desirably is an aluminum substrate which is sujected to anodization processing after subjected to roughening processing, and the aluminum substrate is desirably performed with silicate processing further. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a negative lithographic printing plate precursor comprising a support having a hydrophilic surface and a hydrophilic image forming layer. More specifically, the present invention relates to a lithographic printing plate precursor capable of making a plate by scanning exposure based on a digital signal, and capable of giving a printed material with high sensitivity and high printing durability and free from residual color and stains.

  It consists of a hydrophilic non-image part. As such a lithographic printing plate precursor, conventionally, a PS plate in which an oleophilic photosensitive resin layer (ink receiving layer) is provided on a hydrophilic support has been widely used. From the lithographic printing plate precursor, As a method for making a lithographic printing plate, a desired printing plate is usually obtained by performing mask exposure via a lithographic film and then dissolving and removing the non-image area with a developer.

  In recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread, and various new image output methods corresponding to such digitization technology have been put into practical use. It has become. Along with this, computer-to-plate (CTP) technology that scans a highly directional active radiation such as laser light according to digitized image information and directly produces a printing plate without using a lith film is anxious. Therefore, it is an important technical problem to obtain a printing plate precursor adapted to this.

  On the other hand, in the plate making process in the conventional PS plate, the step of dissolving and removing the non-image portion after the exposure is indispensable, and such additional wet processing is indispensable in the prior art. On the other hand, it is another issue that has been desired to be improved. Particularly in recent years, consideration for the global environment has become a major concern for the entire industry. From the viewpoint of both the environmental aspects and the rationalization of the process accompanying the digitization described above, the simplification, the dry process, and the non-treatment of the process are strongly desired more than before. .

  From this point of view, the following method has been proposed as one of the methods for eliminating the conventional processing steps. That is, using a photosensitive layer that can remove the non-image portion of the printing plate precursor in a normal printing process, without performing a development process, after exposure, the image is developed on a printing machine and the final printing plate is prepared. It is a method to obtain. A lithographic printing plate making method in this way is called an on-press development method. Specific methods include, for example, the use of a photosensitive layer soluble in dampening water or an ink solvent, and a method of performing mechanical removal by contact with an impression cylinder or a blanket cylinder in a printing press. However, when a conventional PS plate is applied to an on-press development printing plate, the photosensitive layer is not fixed after exposure of the original plate. For example, the plate is completely shielded from light and / or until it is mounted on the printing press. Or there was a big problem that it must be stored under constant temperature conditions.

  For the technical problems as described above, as a method for producing a printing plate by scanning exposure, a solid laser such as a semiconductor laser or a YAG laser has recently become available at low cost. A method using these lasers has been considered promising. In the high power density exposure system using these high output lasers, various phenomena different from the photoreaction used in the conventional photosensitive material system for low to medium power density exposure can be used. Specifically, in addition to chemical changes, structural changes such as phase changes and morphological changes can be used. Usually, such a recording method using high power density exposure is called heat mode recording. This is because, in a high power density exposure system, in many cases, light energy absorbed by a light-sensitive material is converted into heat, and it is believed that a desired phenomenon is caused by the generated heat.

  The great advantage of such a heat mode recording method is that it is not essential to fix the image after exposure. That is, since the phenomenon used for image recording of the heat mode light-sensitive material does not substantially occur under exposure to light of ordinary intensity or under ordinary environmental temperature, fixing of the image after exposure is not essential. Therefore, for example, a photosensitive layer that is insolubilized or solubilized by heat mode exposure is used, and after image exposure, an image can be obtained even after exposure to ambient light and development (removal of non-image areas). A system that does not change is possible. Therefore, according to the heat mode recording, it is possible to obtain a lithographic printing plate precursor desirable for the above-described on-press development method.

  As one of the preferred methods for producing a lithographic printing plate based on heat mode recording, a hydrophilic image forming layer is provided on a hydrophilic support, the image is exposed to heat mode, and the hydrophilic layer is soluble and dispersible. A method has been proposed in which the unexposed portion is removed by wet development as required. Further, the conventional heat mode method master has another serious problem that the non-image area is poorly soiled or the image area is weak. That is, it is necessary to improve that the change in solubility due to exposure in the vicinity of the support in the image forming layer is smaller than that in the vicinity of the surface of the image forming layer. In the heat mode type original plate, the heat generation during the heat mode exposure is based on the light absorption of the light absorber in the recording layer, so that the heat generation amount is large on the surface of the recording layer and small in the vicinity of the support. For this reason, the degree of change in the solubility of the recording layer in the vicinity of the support becomes relatively small. As a result, often in a heat mode negative master, the ink receptive layer may be removed during the development and / or printing process in the exposed areas where a hydrophobic ink receptive layer should be provided. Such removal of the image area ink-receptive layer in the negative master causes a problem that printing durability is poor in terms of printing performance. In particular, when a metal support having a high thermal conductivity such as Al, which is preferable in terms of printability, is used, the temperature increase near the support is further hindered by thermal diffusion. is there. In order to obtain a sufficient change in solubility in the vicinity of the substrate, extremely large exposure energy is required, or post-processing such as heating after exposure has to be performed.

  For example, as described in Japanese Patent No. 2938397 (Patent Document 1), thermoplastic hydrophobic polymer fine particles are thermally fused by infrared laser exposure to form an image, and then a plate is placed on a printing machine cylinder. There are methods for on-press development with mounting, fountain solution and / or ink. However, in such a method of simply forming an image by thermal fusion, although good on-machine developability is exhibited, when a heat-sensitive layer is provided directly on the aluminum substrate, the generated heat is taken away by the aluminum substrate, so that the substrate No reaction occurs on the interface of the heat sensitive layer, resulting in insufficient printing durability. Similarly, Japanese Patent Application Laid-Open No. 9-127683 (Patent Document 2) or International Publication No. 99/10186 pamphlet (Patent Document 3) describes that thermoplastic fine particles are thermally fused to form an image by on-machine development. However, the printing durability is insufficient.

Further, as described in JP-A-8-48020 (Patent Document 4), an oleophilic heat-sensitive layer is provided on a porous hydrophilic support, exposed to an infrared laser, and fixed to the substrate by heat. Although a method is mentioned, the on-machine developability is poor in an oleophilic film, and debris of the oleophilic heat-sensitive layer adheres to the ink roller or printed matter. In addition, when the lipophilic heat-sensitive layer is provided on the hydrophilic swelling layer as described in JP-A-10-287062 (Patent Document 5), the absorption of heat by the aluminum substrate is suppressed. If ink is applied in a state where the water-swelling layer is not swollen by the fountain solution, the ink is poorly discharged and the amount of waste paper increases.
Japanese Patent No. 2938397 JP-A-9-127683 WO99 / 10186 pamphlet JP-A-8-48020 Japanese Patent Laid-Open No. 10-287062

  As described above, a heat-sensitive material having good on-press developability, high sensitivity, and high printing durability has not been obtained yet. Accordingly, the object of the present invention is to provide an excellent on-press developability and to obtain more printed matter in a lithographic printing plate precursor that can be developed on a printing press that forms an image by heat. is there.

  The present invention provides a photothermal conversion material by providing a thermosensitive layer comprising a microcapsule containing a compound having a functional group whose outer wall is broken by heat used for image formation and reacts by the heat on a hydrophilic support. By containing it in the heat-sensitive layer or a layer adjacent thereto, a lithographic printing plate precursor that can be developed on a printing press while having good on-press developability and high printing durability is provided.

  The lithographic printing plate precursor of the present invention is a microcapsule containing a compound having a functional group that is broken by heat used for image formation and has a functional group that reacts with heat in a heat-sensitive layer provided on a hydrophilic support. By containing the ink, it is possible to provide a printed material with high sensitivity and high printing durability and free from residual color and smudge, and further exhibit excellent on-press developability, and more printed materials can be obtained. It is a thing. Moreover, by using an anodized aluminum substrate and further an silicate-treated aluminum substrate as the support, better on-press developability could be exhibited.

The present invention will be described in detail below.
[Microcapsule]
The microcapsule used in the present invention contains a compound whose outer wall is broken by heat used for image formation and has a functional group (also referred to as heat-reactive group) that reacts with the heat, and its average particle size is 0.01 μm to 20 μm is preferable, among which 0.05 μm to 2.0 μm is more preferable, and 0.10 μm to 1.0 μm is particularly preferable. If the average particle size is too large, the resolution will be poor, and if it is too small, the stability over time will be poor.

  These microcapsules may have a structure in which the microcapsules can react with each other via the heat-reactive group of the above-described compound contained therein, or a hydrophilic resin described below or a low content as another additive in the heat-sensitive layer. When molecular compounds are contained, a structure capable of reacting with them may be used. Alternatively, two or more types of microcapsules may have a heat-reactive group capable of reacting with each other so that the microcapsules can react with each other. That is, the reaction by these thermally reactive groups includes a polymerization reaction by an unsaturated group, an addition reaction by an isocyanate group or a block thereof and a compound having an active hydrogen atom (for example, amine, alcohol, carboxylic acid, etc.), epoxy Group and amino group / carboxyl group / hydroxyl group addition reaction, carboxyl group and hydroxyl group or amino group condensation reaction, acid anhydride and amino group or hydroxyl group ring-opening addition reaction, etc. These may be any reaction as long as a chemical bond is formed.

  Microcapsules containing such a compound having a heat-reactive group include, for example, acrylate groups, methacrylate groups, vinyl groups, allyl groups, epoxy groups, amino groups, hydroxyl groups, carboxyl groups, isocyanates, acid anhydrides, and the like. It can be obtained by encapsulating a compound having a thermoreactive group such as a group protected in detail (described later in detail) in a microcapsule or introducing these compounds into the outer wall of the microcapsule. In addition, the compound having a heat-reactive group may be encapsulated in the microcapsule and simultaneously introduced into the outer wall of the microcapsule.

  Examples of the compound having a thermally reactive group contained in the microcapsule include a compound having an unsaturated group, and the compound having an unsaturated group is a radically polymerizable compound having at least one ethylenically unsaturated double bond. And selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, unsaturated carboxylic acid ester having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group, amide and monofunctional or polyfunctional isocyanate, addition reaction product of epoxy, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, halogen A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a group or a tosyloxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene or the like instead of the unsaturated carboxylic acid.

  Specific examples of the radical polymerizable compound that is an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butanediol diacrylate. , Tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4- Cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol Triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, etc. is there.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.

  Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149, those containing an amino group described in JP-A-1-165613, and the like are also preferably used.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.

  Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (A) to a polyisocyanate compound having two or more isocyanate groups. Etc.

Formula (A)
_{CH 2 = C (R 41)} COOCH 2 CH (R 42) OH
(However, R ₄₁ and R ₄₂ represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable.

  Furthermore, radical polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 may be used.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337 and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also be mentioned. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, those introduced as photocurable monomers and oligomers in Journal of Japan Adhesion Association vol. 20, No. 7, pages 300 to 308 (1984) can also be used.

  Examples of the epoxy compound include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols, or polyhydrides thereof. A glycidyl ether body etc. are mentioned. The compound having an isocyanate is preferably tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexane phenylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, or alcohols or amines thereof. Examples of the compound blocked with a kind. As the amine compound, ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like are preferably used.

  Preferred examples of the compound having a hydroxyl group include compounds having terminal methylol, polyhydric alcohols such as pentaerythritol, bisphenols and polyphenols, and the like. Preferable examples of the compound having a carboxyl group include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid. Preferable examples of the acid anhydride include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  By including the microcapsules containing the compound having a heat-reactive group specifically described in detail in the heat-sensitive layer of the lithographic printing plate precursor according to the present invention, the outer wall of the microcapsules is heated by the heat during image formation. This is broken and the compound contained in the microcapsule is released into the heat-sensitive layer and causes a chemical reaction, whereby the molecular structure of the image portion of the heat-sensitive layer is changed to a three-dimensional crosslinked body. Therefore, the difference in the solubility of the image portion in water or aqueous solution before and after image formation becomes large, and good on-press developability is exhibited. In addition, since the outer wall of the microcapsule is broken by heat used for image formation, the compound can surely react with the compound outside the microcapsule, so that the crosslinking density of the three-dimensional crosslinked body is very high. It is considered expensive. Therefore, it is considered that an image portion having high strength can be obtained after image formation, and more printed matter can be obtained.

  The preferred microcapsule wall material used in the present invention is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. As described above, a compound having a thermally reactive group may be introduced into the outer wall of the microcapsule.

  As a method for microencapsulating a compound having a heat-reactive group as an inclusion, a known microencapsulation method can be applied. For example, as a method for producing microcapsules, a method using coacervation found in US Pat. Nos. 2,800,547 and 2,800,498, British Patent 990443, US Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, 42-446, 42-711, interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304, polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol wall A method using a material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, a urea-formaldehyde system or a urea formaldehyde-reso found in US Pat. Nos. 4001140, 4087376, and 4089802. A method using a sinol-based wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and a monomer polymerization method as shown in Japanese Patent Publication Nos. 36-9163 and 51-9079. Situ method, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. are not limited thereto.

[Photothermal conversion material]
Further, the lithographic printing plate precursor according to the present invention can carry out image writing by laser light irradiation or the like by containing a photothermal conversion material in the heat sensitive layer or in a layer adjacent thereto. Furthermore, in order to effectively use the heat generated from the photothermal conversion material, the photothermal conversion material is preferably contained in the microcapsules. By containing the photothermal conversion material in the microcapsule, heat can be effectively used for the destruction of the outer wall of the microcapsule, the release of the encapsulated substance, and the reaction activation of the reactant. Thereby, the printing durability of the lithographic printing plate precursor according to the present invention can be improved. The photothermal conversion material is not particularly limited as long as it absorbs the wavelength of the light source such as carbon black, metal fine particles, and a dye, but a compound that absorbs infrared rays and converts it into heat is particularly preferable.

  The photothermal conversion material is particularly preferably a substance that absorbs light of 700 nm or more, and various pigments and dyes can be used. Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology", published by CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed 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. Surface treatment methods include surface coating with a hydrophilic resin or lipophilic resin, a method of attaching a surfactant, a reactive substance (eg, silica sol, alumina sol, silane coupling agent, epoxy compound, isocyanate compound, etc.) A method of bonding to the pigment surface is conceivable. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes. Among these pigments, those that absorb infrared light or near infrared light are particularly preferred because they are suitable for use in lasers that emit infrared light or near infrared light.

  As the pigment that absorbs infrared light or near infrared light, carbon black, carbon black coated with a hydrophilic resin, or carbon black modified with silica sol is preferably used. Among these, carbon black whose surface is coated with a hydrophilic resin or silica sol is useful as it is easily dispersible with a water-soluble resin and does not impair the hydrophilicity.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm. As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like 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 Applied Technology" (CMC Publishing, 1986).

  As the dye, commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by Organic Synthetic Chemical Society, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. Among these dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near infrared light.

  Examples of dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, and US Pat. No. 4,973,572. Cyanine dyes described in JP-A-10-268512, etc., methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc. Disclosed in JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Naphthoquinone dyes, squarylium dyes described in JP-A-58-112792, etc., cyanine dyes described in British Patent 434,875 and US Pat. No. 4,756,993 Dyes Saisho described can include cyanine dyes and dyes described in JP-10-268512 Patent forth described in U.S. Patent 4,973,572.

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are substituted or unsubstituted alkyl groups; Z ¹ and Z ² are substituted or unsubstituted phenyl groups or naphthalene groups; A substituted or unsubstituted methine group, and the substituent is an alkyl group having a carbon number of 8 or less, a halogen atom or an amino group, or the methine group is bonded to the substituents on the two methine carbons; It may include a cyclohexene ring or a cyclopentene ring which may have a substituent formed, and the substituent is an alkyl group having 6 or less carbon atoms or a halogen atom; X is an anionic group; n is 1 or 2; and at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , Z ¹ and Z ² represents an acidic group or a substituent having an alkali metal base or amine base of an acidic group.

[Wherein, R ¹¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; R ¹² and R ¹⁵ represent a hydrogen atom or a group that can be substituted for a hydrogen atom: R ¹³ and R ¹⁴ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkyl group, provided that R ¹³ and R ¹⁴ are not simultaneously a hydrogen atom: R ¹⁶ and R ¹⁷ are substituted or unsubstituted. A substituted alkyl group, a substituted or unsubstituted aryl group, an acyl group or a sulfonyl group, or the formation of a nonmetallic 5-membered or 6-membered ring by R ¹⁶ and R ¹⁷ is shown. ]

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59 -84248, 59-84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes described in U.S. Pat. No. 4,283,475 The pentamethine thiopyrylium salt described in No. 5 and the pyrylium compounds disclosed in JP-B Nos. 5-13514 and 5-19702, Phosphorus Ltd. Epolight III-178, Epolight III-130, Epolight III-125 and the like are particularly preferably used. Among these dyes, when they are encapsulated in microcapsules, those that are soluble in a solvent that is not mixed with water are preferable from the viewpoint of synthesis. More preferred are those that can be dissolved in ethyl acetate. Specific examples include oil-soluble cyanine containing an alkyl chain having 4 or more carbon atoms, oil-soluble phthalocyanine, and oil-soluble polymethine dye. When added outside the microcapsules, the water-soluble cyanine dye of the above formula (I) is particularly preferable. Specific compounds are listed below.

  Next, the photothermal conversion metal fine particles will be described. Many of the metal particles are photothermally convertible and self-heating. As preferable metal fine particles, Si, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ag, Au, Pt, Pd, Rh, In, Sn, W, Te , Pb, Ge, Re, and Sb, or their oxides or sulfides. Among the metals constituting these metal fine particles, preferred metals are metals having a melting point of about 1000 ° C. or less that is easily heat-bonded by light irradiation and having absorption in the infrared, visible, or ultraviolet region, such as Re, Sb, Te, Au, and the like. , Ag, Cu, Ge, Pb and Sn. Particularly preferred are fine metal particles such as Ag, Au, Cu, Sb, Ge, and Pb, which have a relatively low melting point and a relatively high absorbance to heat rays, and particularly preferred elements include Ag, Au, and Cu. .

  For example, fine particles of low melting point metal such as Re, Sb, Te, Au, Ag, Cu, Ge, Pb, Sn and fine particles of self-heating metal such as Ti, Cr, Fe, Co, Ni, W, Ge are used. You may be comprised by 2 or more types of photothermal conversion substances, such as mixing use. In addition, it is preferable to use a combination of a metal piece with a particularly large light absorption when combined with other metal minute pieces such as Ag, Pt, and Pd. The effects of the present invention are further exhibited by subjecting the fine particles of the simple metal and alloy described above to a hydrophilic treatment on the surface. Surface hydrophilization means surface treatment with a hydrophilic compound that has adsorptivity to particles, such as a surfactant, or a surface treatment with a substance having a hydrophilic group that reacts with the constituent material of the particle, A method such as providing a protective colloidal hydrophilic polymer film can be used. Particularly preferred is surface silicate treatment. For example, in the case of iron fine particles, the surface can be sufficiently rendered hydrophilic by a method of dipping in an aqueous solution of sodium silicate (3%) at 70 ° C. for 30 seconds. Other metal fine particles can also be subjected to surface silicate treatment by the same method.

  The particle diameter of these particles is 10 μm or less, preferably 0.003 to 5 μm, and more preferably 0.01 to 3 μm. The finer the temperature, the lower the thermal fusing temperature, that is, the higher the heat mode photosensitivity, which is advantageous, but the dispersion of the particles is difficult, and the resolution of the printed matter is worse at 10 μm or more. In the present invention, when these photothermal conversion materials are used, the addition amount is 1% by weight or more, preferably 2% by weight or more, particularly preferably 5% by weight or more in the total solid content of the heat-sensitive layer. . If the content of the photothermal conversion material is less than 1% by weight, the sensitivity is lowered.

[Hydrophilic resin]
A hydrophilic resin may be added to the heat-sensitive layer of the lithographic printing plate precursor according to the invention. By adding a hydrophilic resin, not only the on-press developability is improved, but also the film strength of the thermosensitive layer itself is increased. A hydrophilic resin that is not three-dimensionally cross-linked is preferred because of good on-press developability. As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and their Na salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids And salts thereof, polymethacrylic acids and salts thereof, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxy Homopolymers and copolymers of butyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene Glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight, Mention may be made of homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, and homopolymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid and its salts.

  The amount of the hydrophilic resin added to the heat-sensitive layer is preferably 2% to 40%, more preferably 3% to 30%. When it is less than 2%, the film strength is weak, and when it is more than 40%, the on-press developability is improved but the printing durability is deteriorated.

[Compound that initiates or accelerates the reaction]
In the heat-sensitive layer of the lithographic printing plate precursor according to the present invention, microcapsules containing a compound having the above-mentioned heat-reactive group are used. Therefore, if necessary, a compound that initiates or accelerates these reactions may be added. May be. Examples include compounds that generate radicals or cations by heat, such as lophine dimers, trihalomethyl compounds, peroxides, azo compounds, diazonium salts or diphenyliodonium salts, onium salts, acylphosphines, imide sulfones. Narto etc. are mentioned. These compounds can be added in the range of 1% by weight to 20% by weight in the heat sensitive layer. Preferably it is the range of 3 weight%-10 weight%. If the amount is more than this, the on-press developability deteriorates, and if it is less than this, the reaction initiation or acceleration effect becomes weak and the printing durability deteriorates.

  Moreover, in order to advance reaction efficiently, it is preferable to contain the compound which starts or accelerates | stimulates reaction in a microcapsule. By containing these compounds in the microcapsules, it can be well mixed with the compound having a heat-reactive group in advance, and when irradiated with a laser, the reaction can be performed while the inclusions are released. Thereby, the printing durability of the lithographic printing plate precursor according to the present invention can be further improved.

[Low molecular weight compound that reacts with compound having thermoreactive group contained in microcapsule]
The heat-sensitive layer of the lithographic printing plate precursor according to the invention further has a functional group capable of reacting with a compound having a heat-reactive group contained in the microcapsule by heat used for image formation and a protective group thereof. A low molecular weight compound can be contained. The amount of these compounds added is preferably 5% by weight to 40% by weight in the heat sensitive layer, and particularly preferably 5% by weight to 20% by weight. If it is less than this, the crosslinking effect is small and the printing durability is insufficient, and if it is more than this, the on-press developability after aging deteriorates. Specific examples of such a compound include the same compounds as those of the compound having a thermally reactive group contained in the microcapsule.

[Other additives]
In the present invention, various compounds other than these may be added as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant. 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 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in No. 293247. In addition, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can also be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. In addition, the addition amount is a ratio of 0.01 to 10% by weight with respect to the total solid content of the heat-sensitive layer coating solution.

  In the present invention, a small amount of a thermal polymerization inhibitor is added in order to prevent unnecessary thermal polymerization of a compound having an ethylenically unsaturated double bond capable of radical polymerization during preparation or storage of a heat-sensitive layer coating solution. It is desirable to do. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by weight to about 5% by weight with respect to the weight of the total composition. If necessary, higher fatty acid derivatives such as behenic acid and behenic acid amide may be added to prevent polymerization inhibition by oxygen, and may be unevenly distributed on the surface of the heat-sensitive layer in the course of drying after coating. . The amount of the higher fatty acid derivative added is preferably from about 0.1% to about 10% by weight of the total composition.

  Further, in the heat-sensitive layer coating solution of the present invention, a nonionic surfactant as described in JP-A-62-251740 or JP-A-3-208514 is used in order to broaden the processing stability against development conditions. , Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.

  Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N, N- Examples include betaine type (for example, trade name Amorgen K, manufactured by Dai-ichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and the amphoteric surfactant in the heat-sensitive layer coating solution is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

  Furthermore, a plasticizer is added to the heat-sensitive layer coating liquid according to the present invention, if necessary, in order to impart flexibility of 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 and the like are used.

  In order to produce the lithographic printing plate precursor according to the present invention, the above-mentioned components necessary for the heat-sensitive layer coating solution are usually dissolved in a solvent and coated on a suitable support. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, it is not limited to this. These solvents are used alone or in combination. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by weight.

Moreover, although the heat-sensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the use, it is generally preferably 0.5 to 5.0 g / m ² for a lithographic printing plate precursor. Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the heat-sensitive layer that performs the image recording function decrease.

  In the heat-sensitive layer coating liquid according to the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant as described in JP-A-62-170950 can be added. . A preferable addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the solid content of the material of the entire heat sensitive layer.

[Overcoat layer]
In the lithographic printing plate precursor according to the invention, a water-soluble overcoat layer can be provided on the heat-sensitive layer in order to prevent contamination of the surface of the heat-sensitive layer with an oleophilic substance. The water-soluble overcoat layer used in the present invention can be easily removed during printing and contains a resin selected from water-soluble organic polymer compounds. As the water-soluble organic polymer compound used here, a film formed by coating and drying has film-forming ability. Specifically, polyvinyl acetate (however, a hydrolysis rate of 65% or more), polyacrylic Acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal salt or amine Salt, polyacrylamide and copolymer thereof, polyhydroxyethyl acrylate, polyvinylpyrrolidone and copolymer thereof, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamide-2-methyl-1- Propanesulfonic acid and its alkali Metal salt or amine salt, poly-2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and alkali metal salt or amine salt thereof, gum arabic, fiber derivative (for example, carboxymethyl cellulose, carboxyethyl cellulose, Methyl cellulose, etc.) and modified products thereof, white dextrin, pullulan, enzymatically decomposed etherified dextrin and the like. Further, two or more kinds of these resins can be mixed and used depending on the purpose.

Further, the water-soluble photothermal conversion agent may be added to the overcoat layer. Furthermore, in order to ensure the uniformity of coating, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether can be added to the overcoat layer in the case of aqueous solution coating. . The dry coating amount of the overcoat layer is preferably 0.1 to 2.0 g / m ² . If it is less than that, fingerprint adhesion contamination will occur, and if it is more than that, the on-press developability will be poor.

[Support]
The hydrophilic support to which the heat-sensitive layer can be applied in the lithographic printing plate precursor according to the present invention is a dimensionally stable plate-like material such as paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.). Laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene , Polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which a metal as described above is laminated or vapor-deposited. A preferable support includes a polyester film or an aluminum plate.

  As the support used for the lithographic printing plate precursor according to the present invention, it is preferable to use an aluminum plate that is lightweight and excellent in surface treatment, workability, and corrosion resistance. Aluminum materials used for this purpose include JIS 1050, JIS 1100, JIS 1070, Al-Mg alloy, Al-Mn alloy, Al-Mn-Mg alloy, Al-Zr alloy, Al -Mg-Si based alloys and the like.

Known techniques relating to aluminum materials that can be used for the support are listed below.
(1) Regarding the JIS 1050 material, the following technology is disclosed.
JP 59-153861, JP 61-51395, JP 62-146694, JP 60-215725, JP 60-215726, JP 60-215727, JP 60-215728, JP-A-61-272357, JP-A-58-11759, JP-A-58-42493, JP-A-58-212254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3 -68939, JP-A-3-234594, JP-B-1-47545, JP-A-62-140894, and the like. Japanese Patent Publication No. 1-35910, Japanese Patent Publication No. 55-28874, and the like are also known.

(2) Regarding the JIS 1070 material, the following technology is disclosed.
JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108659, JP-A-8-92679, and the like.

(3) Regarding the Al—Mg alloy, the following technique is disclosed.
JP-B-62-5080, JP-B-63-60823, JP-B-3-61753, JP-A-60-203497, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-2 23794, JP-A 63-47347, JP-A 63-47348, JP-A 63-47349, JP-A 64-61293, JP-A 63-135294, JP-A 63-87288, JP-B 4-73392, Japanese Patent Publication No. 7-100904, Japanese Patent Publication No. 62-149856, Japanese Patent Publication No. 4-73394, Japanese Patent Publication No. Sho 62-181191, Japanese Patent Publication No. 5-76530, Japanese Patent Publication No. 63-30294, Japanese Patent Publication No. 6-37116, and the like. JP-A-2-215599, JP-A-61-201747, and the like are also known.

(4) Regarding the Al—Mn alloy, the following techniques are disclosed.
JP-A-60-230951, JP-A-1-306288, JP-A-2-293189, and the like. JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51592, US5009722, US5028276, JP-A-4-226394, etc. Is also known.
(5) Regarding the Al—Mn—Mg based alloy, the following techniques are disclosed.
JP-A-62-286143, JP-A-3-222296, JP-B-63-60824, JP-A-60-63346, JP-A-60-63347, EP223737, JP-A-1-283350, US48818300, BR1222777 and the like are known. .

(6) The following techniques are known for Al—Zr alloys.
Japanese Patent Publication Nos. 63-15978, 61-513395, 63-143234, 63-143235 and the like are known.
(7) Regarding the Al—Mg—Si based alloy, BR14221710 and the like are known.

  Moreover, the following content can be used as a manufacturing method of the aluminum plate for support bodies. The aluminum alloy melt containing the above-described components and alloy components is subjected to a cleaning treatment according to a conventional method and cast. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using Ar gas, Cl gas, etc., so-called rigid media such as ceramic tube filter, ceramic foam filter, etc. Filtering using a filter, a filter using alumina flakes, alumina balls, or the like, a filtering using a glass cloth filter, or a combination of degassing and filtering is performed. These cleaning treatments are desirably carried out in order to prevent defects due to foreign matters such as non-metallic inclusions and oxides in the molten metal, and defects due to gas dissolved in the molten metal.

  Regarding the filtering of molten metal, JP-A-6-57342, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-312661, JP-A-6-136466, etc. are known. It has been. Regarding degassing of the molten metal, Japanese Patent Laid-Open Nos. 5-51659, 5-51660, 5-49148, and 7-70017 are known. As described above, casting is performed using the molten metal that has been subjected to the cleaning treatment. As for the casting method, there are a method using a fixed mold represented by a DC casting method and a method using a driving mold represented by a continuous casting method. When the DC casting method is used, the cooling rate is solidified in the range of 1 to 300 ° C./second. When it is less than 1 ° C./second, a large number of coarse intermetallic compounds are formed.

  For the continuous casting method, a method using a cooling roll represented by the Hunter method and the 3C method, a Hazeley method, a cooling belt represented by Al Swiss Caster II, and a method using a cooling block are industrially used. It has been broken. When the continuous casting method is used, the cooling rate is solidified in the range of 100 to 1000 ° C./second. In general, since the cooling rate is higher than that in the DC casting method, there is a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. With respect to the continuous casting method, the inventors of the present application disclosed in Japanese Patent Laid-Open Nos. 3-79798, 5-201166, 5-156414, 6-262203, 6-122949, 6-210406, 6-210406, 6-262308 and the like are disclosed.

  When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be produced. The ingot is chamfered according to a conventional method, and 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Thereafter, soaking treatment is performed as necessary. When performing the soaking process, heat treatment is performed at 450 to 620 ° C. for 1 hour or more and 48 hours or less so that the intermetallic compound does not become coarse. When it is shorter than 1 hour, the effect of the soaking treatment is insufficient. Next, hot rolling and cold rolling are performed to obtain an aluminum rolled sheet. The hot rolling start temperature is in the range of 350 to 500 ° C. An intermediate annealing treatment may be performed before, after, or during the cold rolling. The intermediate annealing conditions in this case are a method of heating at 280 ° C. to 600 ° C. for 2 to 20 hours using a batch type annealing furnace, preferably 2 to 10 hours at 350 to 500 ° C., or 400 using a continuous annealing furnace. A heat treatment at ˜600 ° C. for 360 seconds or shorter, desirably 450-550 ° C. for 120 seconds or shorter can be employed. When heated using a continuous annealing furnace at a heating rate of 10 ° C./second or more, the crystal structure can be made finer.

  In order to improve the flatness of the Al plate finished to a predetermined thickness of 0.1 to 0.5 mm by the above steps, the flatness may be improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the plate is cut into a sheet, but in order to improve the productivity, it is desirable to improve the flatness in a continuous coil state. Further, in order to process the plate width into a predetermined width, a slitter line is usually passed. When the end face of the plate cut by the slitter is cut by the slitter blade, one or both of a shear plane and a fracture surface are generated.

  The accuracy of the thickness of the plate is within ± 10 μm, preferably within ± 6 μm over the entire length of the coil. The plate thickness difference in the width direction is within 6 μm, preferably within 3 μm. Further, the accuracy of the plate width is within ± 1.0 mm, preferably within ± 0.5 mm. The surface roughness of the Al plate is likely to be affected by the surface roughness of the rolling roll, but it is preferable that the surface roughness is finally about Ra = 0.1 to 1.0 μm as the centerline surface roughness (Ra). If Ra is too large, when roughening treatment for lithographic printing plate and heat sensitive layer application, the original roughness of Al, that is, rough rolling streaks transferred by the rolling roll can be seen from above the heat sensitive layer. It is not preferable in appearance. A roughness of Ra = 0.1 μm or less is industrially undesirable because it is necessary to finish the surface of the rolling roll with an excessively low roughness.

Further, a thin oil film may be provided on the surface of the Al plate in order to prevent generation of scratches due to friction between the Al plates. As the oil film, a volatile or non-volatile film is appropriately used as necessary. If the amount of oil is too large, a slip failure will occur in the production line, but if there is no amount of oil, there will be a problem that scratches will occur during coil transportation, so the amount of oil will be 3 mg / m ² or more and 100 mg / m ^2. Hereinafter, the desirable upper limit is 50 mg / m ² or less, and more desirably 10 mg / m ² or less. Regarding cold rolling, JP-A-6-210308 and the like are disclosed.

  When continuous casting is performed, for example, when a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly continuously cast and rolled, and a merit that a hot rolling process can be omitted is obtained. Further, when a cooling roll such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled, so that a thickness of 1 to 1 is obtained. A 10 mm continuous cast and rolled plate is obtained. These continuous cast and rolled sheets are finished to a thickness of 0.1 to 0.5 mm through processes such as cold rolling, intermediate annealing, flatness improvement, and slitting, as described in the case of DC casting. It is done. Regarding the intermediate annealing condition and the cold rolling condition when the continuous casting method is used, JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, JP-A-8-92709, and the like are disclosed.

  The Al plate produced by the above method can be subjected to a surface treatment such as a roughening treatment on the surface, and a heat-sensitive layer can be applied to form a lithographic printing plate precursor. In the roughening treatment, mechanical roughening, chemical roughening, and electrochemical roughening are performed alone or in combination. Moreover, it is also preferable to perform an anodizing process for ensuring the scratch resistance of the surface or a process for increasing hydrophilicity.

  The surface treatment of the support will be described below. Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing rolling oil on the surface may be performed as necessary. In the case of an alkali, treatments such as neutralization and smut removal may be performed with an acidic solution.

  Next, in order to improve the adhesion between the support and the heat-sensitive layer and to provide water retention to the non-image area, a so-called graining treatment is performed to roughen the surface of the support. Specific means of this graining method include sandblasting, ball grain, wire grain, nylon brush and brush grain made of abrasive / water slurry, mechanical sand made of honing grain that sprays abrasive / water slurry on the surface at high pressure, etc. There is a sharpening method, and there is a chemical sanding method in which the surface is roughened with an etching agent comprising an alkali, an acid, or a mixture thereof. Further, the electrochemical graining method described in British Patent No. 896,563, JP-A-53-67507, JP-A-54-146234 and JP-B-48-28123, or JP A method combining the mechanical graining method and the electrochemical graining method described in JP-A-53-123204 and JP-A-54-63902, described in JP-A-56-55261 A combination of a mechanical graining method and a chemical graining method with a saturated aqueous solution of an aluminum salt of a mineral acid is also known. In addition, the above-mentioned support material is bonded with a granular material by an adhesive or a method having an effect thereof, and the surface is roughened, or a continuous band or roll having fine unevenness is pressure-bonded to the support material to form unevenness. The rough surface may be formed by transferring.

  These roughening methods may be performed in combination, and the order, the number of repetitions, and the like can be arbitrarily selected. When a plurality of roughening treatments are combined, chemical treatment with an acid or alkaline aqueous solution can be performed in order to uniformly perform the subsequent roughening treatment. Specific examples of the acid or alkali aqueous solution include acids such as hydrofluoric acid, fluorinated zirconic acid, phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid, and alkali aqueous solutions such as sodium hydroxide, sodium silicate, and sodium carbonate. . These acid or alkali aqueous solutions can be used alone or in combination of two or more. The chemical treatment is generally carried out using a 0.05 to 40% by weight aqueous solution of these acids or alkalis at a liquid temperature of 40 to 100 ° C. for 5 to 300 seconds.

  Since smut is formed on the surface of the support obtained by the roughening treatment, that is, the graining treatment as described above, a treatment such as washing with water or alkali etching is appropriately performed to remove the smut. Is generally preferred. Examples of such treatment include treatment methods such as the alkali etching method described in Japanese Patent Publication No. 48-28123 and the sulfuric acid desmut method described in Japanese Patent Laid-Open No. 53-12739. In the case of the aluminum support used in the present invention, after the pretreatment as described above, an oxide film is usually formed on the support by anodic oxidation in order to improve wear resistance, chemical resistance and water retention. To form.

Any electrolyte that forms a porous oxide film can be used for the anodizing treatment of an aluminum plate, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. . The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used and cannot be specified. However, in general, the electrolyte concentration is 1 to 80% solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. It is appropriate if the voltage is in the range of 1 to 100 V and the electrolysis time is in the range of 10 seconds to 5 minutes. The amount of the anodized film is suitably 1.0 g / m ² or more, but more preferably in the range of 2.0 to 6.0 g / m ^2. When the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the lithographic printing plate is easily scratched, so that the ink adheres to the scratched part during printing. “Scratches and dirt” are likely to occur.

Such anodizing treatment is applied to the surface used for printing on the support of the lithographic printing plate, but an anodized film of 0.01 to 3 g / m ² is also formed on the back surface due to the back of the lines of electric force. It is common to form. In addition, an alkaline aqueous solution (for example, a several percent aqueous solution of caustic soda), an anodizing treatment in a molten salt, an anodizing treatment for forming a nonporous anodized film using an aqueous ammonium borate solution, or the like can also be performed. . Before the anodizing treatment, a hydrated oxide film described in JP-A-4-148991 and JP-A-4-97896 may be formed. A treatment in a metal silicate solution described in 63-67295, a hydrated oxide film production treatment, a chemical film production treatment described in JP-A-56-144195, and the like can also be performed.

  The aluminum support used in the lithographic printing plate precursor according to the present invention can be treated with an organic acid or a salt thereof after anodizing treatment, or the organic acid or a salt thereof can be used as an undercoat layer applied with a heat-sensitive layer. Examples of the organic acid or salt thereof include organic carboxylic acid, organic phosphonic acid, organic sulfonic acid or salt thereof, and the organic carboxylic acid or salt thereof is preferable. Examples of organic carboxylic acids include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lauric acid, palmitic acid and stearic acid; unsaturated aliphatic monocarboxylic acids such as oleic acid and linoleic acid; oxalic acid and succinic acid Aliphatic dicarboxylic acids such as acid, adipic acid and maleic acid; oxycarboxylic acids such as lactic acid, gluconic acid, malic acid, tartaric acid and citric acid; aromatic carboxylic acids such as benzoic acid, mandelic acid, salicylic acid and phthalic acid; and Ia IIb, IIIb, IVa, VIb and Group VIII metal salts and ammonium salts. Among the organic carboxylates, the metal salts and ammonium salts of formic acid, acetic acid, butyric acid, propionic acid, lauric acid, oleic acid, succinic acid and benzoic acid are preferable. These compounds may be used alone or in combination of two or more.

  These compounds are preferably dissolved in water and alcohol to a concentration of 0.001 to 10% by weight, particularly 0.01 to 1.0% by weight. The treatment conditions are 25 to 95 ° C., preferably 50 The temperature range of ˜95 ° C. and the pH is 1 to 13, preferably 2 to 10 minutes, 10 seconds to 20 minutes, preferably 10 seconds to 3 minutes, or the treatment liquid is applied to the support.

  Further, after the anodizing treatment, treatment with a compound solution as described below, or these compounds can be used as an undercoat layer applied with a heat sensitive layer. Suitable compounds include, for example, phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, which may have a substituent, substituted Organic phosphoric acid such as phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a group, phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid which may have a substituent Amino acids such as organic phosphinic acid, glycine, β-alanine, valine, serine, threonine, aspartic acid, glutamic acid, arginine, lysine, tryptophan, parahydroxyphenylglycine, dihydroxyethylglycine, anthranilic acid; sulfamic acid Aminosulfonic acids such as cyclohexylsulfamic acid; 1-aminomethylphosphonic acid, 1-dimethylaminoethylphosphonic acid, 2-aminoethylphosphonic acid, 2-aminopropylphosphonic acid, 4-aminophenylphosphonic acid, 1-aminoethane-1, 1-diphosphonic acid, 1-amino-1-phenylmethane-1,1-diphosphonic acid, 1-dimethylaminoethane-1,1-diphosphonic acid, 1-dimethylaminobutane-1,1-diphosphonic acid, ethylenediaminetetramethylene Examples thereof include compounds such as aminophosphonic acid such as phosphonic acid.

  Also suitable are salts of hydrochloric acid, sulfuric acid, nitric acid, sulfonic acid (methanesulfonic acid, etc.) or oxalic acid with alkali metal, ammonia, lower alkanolamine (triethanolamine, etc.), lower alkylamine (triethylamine, etc.), etc. Can be used.

  Polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, polyethyleneimine and its mineral salt, poly (meth) acrylic acid and its metal salt, polystyrene sulfonic acid and its metal salt, (meth) acrylic acid alkyl ester and 2-acrylamide-2- A water-soluble polymer such as methyl-1-propanesulfonic acid and its metal salt, a trialkylammonium chloride methylstyrene polymer and a copolymer thereof with (meth) acrylic acid, and polyvinylphosphonic acid can also be suitably used. Furthermore, soluble starch, carboxymethyl cellulose, dextrin, hydroxyethyl cellulose, gum arabic, guar gum, sodium alginate, gelatin, glucose, sorbitol and the like can be suitably used. These compounds may be used alone or in combination of two or more.

  In the case of treatment, these compounds are preferably dissolved in water and / or methyl alcohol to a concentration of 0.001 to 10% by weight, particularly 0.01 to 1.0% by weight. The support is immersed in a temperature range of ˜95 ° C., preferably 50 to 95 ° C., pH 1 to 13, preferably 2 to 10, 10 seconds to 20 minutes, preferably 10 seconds to 3 minutes.

When used as an undercoat layer for heat-sensitive layer application, it is similarly dissolved in water and / or methyl alcohol to a concentration of 0.001 to 10% by weight, particularly 0.01 to 1.0% by weight, and if necessary The pH can be adjusted with a basic substance such as ammonia, triethylamine, potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid, and the pH can be used in the range of 1-12. A yellow dye can also be added to improve the tone reproducibility of the lithographic printing plate precursor. The coating amount after drying of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , a sufficient effect for the original purpose such as prevention of contamination cannot be obtained. On the other hand, if it exceeds 200 mg / m ² , the printing durability decreases.

An intermediate layer for improving the adhesion between the support and the heat-sensitive layer may be provided. In order to improve the adhesion, the intermediate layer is generally composed of a diazo resin, a phosphoric acid compound adsorbed on aluminum, for example. The thickness of the intermediate layer is arbitrary, and it must be a thickness capable of performing a uniform bond-forming reaction with the upper heat-sensitive layer when exposed. Usually, the application ratio of about 1 to 100 mg / m ² is good as a dry solid, and 5 to 40 mg / m ² is particularly good. The ratio of the diazo resin used in the intermediate layer is 30 to 100%, preferably 60 to 100%.

  Prior to the treatment and application of the undercoat layer as described above, the anodized support is washed with water, and then the dissolution of the anodized film in the developer and fountain solution is suppressed, and the residual film of the heat-sensitive layer component is suppressed. The following treatments can be performed for the purpose of improving the strength of the anodized film, improving the hydrophilicity of the anodized film, and improving the adhesion to the heat-sensitive layer. One example is a silicate treatment in which the anodic oxide film is treated by bringing it into contact with an alkali metal silicate aqueous solution. In this case, the concentration of the alkali metal silicate is 0.1 to 30% by weight, preferably 0.5 to 15% by weight, and 5 to 80 ° C. in an aqueous solution having a pH of 10 to 13.5 at 25 ° C. The contact is preferably performed at 10 to 70 ° C., more preferably at 15 to 50 ° C. for 0.5 to 120 seconds. The contact method may be any method, such as dipping or spraying. When the pH of the alkali metal silicate aqueous solution is lower than 10, the solution gels, and when it is higher than 13.5, the anodized film is dissolved.

  As the alkali metal silicate used in the present invention, sodium silicate, potassium silicate, lithium silicate and the like are used. Examples of the hydroxide used for adjusting the pH of the alkali metal silicate aqueous solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend an alkaline-earth metal salt or a group IVb metal salt with the said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble salts such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Is mentioned. Examples of the Group IVb metal salt include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium potassium oxalate, titanium sulfate, titanium tetraiodide, and zirconium chloride oxide. Alkaline earth metals or Group IVb metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by weight, and more preferably 0.05 to 5.0% by weight.

In addition, various sealing treatments are also mentioned, and generally known as a sealing treatment method for an anodized film, water vapor sealing, boiling water (hot water) sealing, metal salt sealing (chromate). / Bichromate seal, nickel acetate seal, etc.), oil-impregnated seal, synthetic resin seal, low temperature seal (due to red blood salt or alkaline earth salt, etc.) can be used. Water vapor sealing is relatively preferred from the standpoints of performance as a support for a substrate (adhesion and hydrophilicity with a heat-sensitive layer), high-speed processing, low cost, low pollution, and the like. As the method, for example, a pressurized or normal pressure steam disclosed in JP-A-4-176690 is continuously or non-continuously set at a relative humidity of 70% or more and a steam temperature of 95 ° C. or more for 2 seconds to 180 seconds. For example, a method of contacting the anodized film for about 2 seconds may be mentioned. Other sealing treatment methods include a method of immersing or spraying the support in hot water or an alkaline aqueous solution of about 80 to 100 ° C., or alternatively, or subsequently immersing or spraying with a nitrous acid solution. it can. Examples of nitrites include nitrites or ammonium salts of metals of groups Ia, IIa, IIb, IIIb, IVb, IVa, VIa, VIIa, VIII of the periodic table, i.e. ammonium nitrite, For example, LiO ₂ , NaNO ₂ , KNO ₂ , Mg (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ , Zn (NO ₃ ) ₂ , Al (NO ₂ ) ₃ , Zr (NO ₂ ) ₄ , Sn (NO ₂₎ ) ₃ , Cr (NO ₂ ) ₃ , Co (NO ₂ ) ₂ , Mn (NO ₂ ) ₂ , Ni (NO ₂ ) _{2 and the} like are preferable, and alkali metal nitrite is particularly preferable. Two or more nitrites can be used in combination.

  The treatment conditions vary depending on the state of the support and the type of alkali metal, and therefore cannot be uniquely determined. For example, when sodium nitrite is used, the concentration is generally 0.001 to 10% by weight, more Preferably 0.01 to 2 wt%, bath temperature is generally from room temperature to about 100 ° C, more preferably 60 to 90 ° C, treatment time is generally 15 to 300 seconds, more preferably 10 to 180. Select from each range of seconds. The pH of the aqueous nitrous acid solution is preferably adjusted to 8.0 to 11.0, particularly preferably 8.5 to 9.5. In order to adjust the pH of the aqueous nitrous acid solution to the above range, it can be suitably prepared using, for example, an alkaline buffer solution or the like. Examples of the alkaline buffer include, but are not limited to, a mixed aqueous solution of sodium bicarbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium bicarbonate, sodium chloride and sodium hydroxide. A mixed aqueous solution, a mixed aqueous solution of hydrochloric acid and sodium carbonate, a mixed aqueous solution of sodium tetraborate and sodium hydroxide, or the like can be suitably used. The alkali buffer may be an alkali metal salt other than sodium, such as a potassium salt.

  After performing the silicate treatment or the sealing treatment as described above, an acidic aqueous solution treatment and a hydrophilic undercoat disclosed in JP-A-5-278362 can be performed in order to improve the adhesion with the heat-sensitive layer. An organic layer disclosed in JP-A-4-282737 and JP-A-7-314937 may be provided.

After the above-described treatment or undercoating is applied to the support surface, a back coat is provided on the back surface of the support as necessary. As such a back coat, a coating layer made of a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174 is used. Preferably used. Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , and Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide obtained therefrom is particularly preferable because of its excellent developer resistance.

  A preferable characteristic as a support for a lithographic printing plate is a center line average roughness of 0.10 to 1.2 μm. If it is lower than 0.10 μm, the adhesiveness with the heat-sensitive layer is lowered, resulting in a significant reduction in printing durability. When it is larger than 1.2 μm, the stain property at the time of printing deteriorates. Further, the color density of the support is 0.15 to 0.65 as a reflection density value. If the density is whiter than 0.15, the halation at the time of image exposure is too strong, which hinders image formation, and 0.65. In the case of a blacker color, it is difficult to see the image in the plate inspection work after development, and the plate inspection property is extremely poor.

  The lithographic printing plate precursor according to the present invention can obtain better on-press developability by using an aluminum substrate that has been subjected to roughening and then anodized as the support. . In that case, it is more preferable to use an aluminum substrate that has been further silicate-treated.

  This printing plate is a hydrophilic layer insoluble in water on an aluminum substrate, a hydrophilic layer that generates heat by laser exposure and is insoluble in water, or a heat insulating layer made of an organic polymer to provide heat insulation on the aluminum substrate. In addition, a hydrophilic layer insoluble in water or a hydrophilic layer that generates heat by laser exposure and is insoluble in water may be provided. For example, a hydrophilic layer of silica fine particles and a hydrophilic resin may be provided on an aluminum substrate. Furthermore, the photothermal conversion material listed above may be introduced into the hydrophilic layer to form an exothermic hydrophilic layer. This makes it difficult for heat to escape to the aluminum substrate, or it can be used as a hydrophilic substrate that generates heat by laser exposure. Furthermore, if an intermediate layer made of an organic polymer is provided between the hydrophilic layer and the aluminum substrate, it is possible to further prevent heat from escaping to the aluminum substrate. The support is preferably not porous from the viewpoint of on-press developability, and the support that swells with water containing 40% or more of the hydrophilic organic polymer material has a problem that ink is difficult to be removed. turn into.

  The hydrophilic layer used in the present invention is three-dimensionally cross-linked, is a layer that does not dissolve in immersion water in lithographic printing using water and / or ink, and is preferably composed of the following colloids. It is a colloid comprising a sol-gel conversion system of oxide or hydroxide of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony or transition metal. In some cases, it may be a colloid composed of a complex of these elements. These colloids have a structure in which the above elements form a network structure through oxygen atoms and at the same time have an unbonded hydroxyl group or alkoxy group, and these are mixed. From the initial hydrolysis-condensation stage where there are many active alkoxy groups and hydroxyl groups, the particle size increases and becomes inactive as the reaction proceeds. The colloidal particles are generally 2 nm to 500 nm, and in the case of silica, those having a spherical shape of 5 nm to 100 nm are suitable in the present invention. A feather-like material such as 100 × 10 nm like an aluminum colloid is also effective. Furthermore, a pearl neck colloid in which spherical particles of 10 nm to 50 nm are connected in a length of 50 nm to 400 nm can also be used.

  The colloid may be used alone or may be used by mixing with a hydrophilic resin. In order to promote crosslinking, a colloidal crosslinking agent may be added. Usually, colloids are often stabilized by stabilizers. In a colloid charged with a cation, a compound having an anion group is added as a stabilizer, whereas in a colloid charged with an anion, a compound having a cation group is added as a stabilizer. For example, since an anion is charged in a colloid of silicon, an amine compound is added as a stabilizer, and in a colloid of aluminum, a cation is charged, so a strong acid such as hydrochloric acid or acetic acid is added. When such a colloid is coated on a substrate, many of them form a transparent film at room temperature, but gelation is incomplete when the solvent of the colloid is evaporated, and heating to a temperature at which the stabilizer can be removed. , A strong tertiary cross-linking is performed, and a hydrophilic layer preferable for the present invention is obtained.

  Without using a stabilizer as described above, a hydrolytic condensation reaction is directly performed from a starting material (for example, di, tri and / or tetraalkoxysilane), an appropriate sol state is created, and is directly coated on a substrate. The reaction may be completed by drying. In this case, three-dimensional crosslinking can be performed at a lower temperature than when a stabilizer is included.

  In addition, a colloid obtained by dispersing and stabilizing an appropriate hydrolysis-condensation reaction product in an organic solvent is also suitable for the present invention. A film that is three-dimensionally crosslinked can be obtained simply by evaporating the solvent. When a solvent having a low boiling point such as methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether or methyl ethyl ketone is selected as these solvents, drying at room temperature becomes possible. In particular, in the present invention, a colloid of methanol or ethanol solvent is useful because it can be easily cured at a low temperature.

  As hydrophilic resin used with said colloid, what has hydrophilic groups, such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl, is preferable, for example. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and their sodium salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids And salts thereof, polymethacrylic acids and salts thereof, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxy Homopolymers and copolymers of butyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene Recalls, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight, Mention may be made of homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, and homopolymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid or its salts.

  Particularly preferred hydrophilic resins are hydroxyl-containing polymers that are not water soluble, specifically hydroxyethyl methacrylate homopolymers and copolymers and copolymers of hydroxyethyl acrylate. These hydrophilic resins are used together with colloids, but the addition ratio is preferably 40% by weight or less based on the total solid content of the hydrophilic layer when the hydrophilic resin is water-soluble, and the total solid content when the hydrophilic resin is not water-soluble. It is preferably 20% by weight or less.

  Although these hydrophilic resins can be used as they are, a crosslinking agent for hydrophilic resins other than colloids may be added for the purpose of increasing the printing durability during printing. Examples of such a hydrophilic resin crosslinking agent include initial hydrolysis / condensation products of formaldehyde, glyoxal, polyisocyanate and tetraalkoxysilane, dimethylol urea and hexamethylol melamine. In addition to the above-mentioned oxide or hydroxide colloid and hydrophilic resin, the hydrophilic layer of the present invention may contain a crosslinking agent that promotes crosslinking of the colloid. As such a crosslinking agent, an initial hydrolysis condensate of tetraalkoxysilane, trialkoxysilylpropyl-N, N, N-trialkylammonium halide or aminopropyltrialkoxysilane is preferable. The addition ratio is preferably 5% by weight or less of the total solid content of the hydrophilic layer.

  Furthermore, a hydrophilic photothermal conversion material may be added to the hydrophilic layer of the present invention in order to increase the thermal sensitivity. A particularly preferred photothermal conversion material is a water-soluble infrared-absorbing dye, which is a cyanine dye having a sulfonic acid group of formula (I) or an alkali metal base or an amine base of sulfonic acid. The addition ratio of these dyes is 1% by weight to 20% by weight, more preferably 5% by weight to 15% by weight, based on the total amount of the hydrophilic layer.

The coating thickness of the three-dimensionally crosslinked hydrophilic layer of the present invention is preferably 0.1 μm to 10 μm. More preferably, it is 0.5 μm to 5 μm. If it is too thin, the durability of the hydrophilic layer is inferior and the printing durability during printing is inferior. If it is too thick, the resolution is lowered. Hereinafter, an intermediate layer made of an organic polymer will be described. The organic polymer that can be used for the intermediate layer can be used without any problem as long as it is a commonly used organic polymer such as polyurethane resin, polyester resin, acrylic resin, cresol resin, resol resin, polyvinyl acetal resin, vinyl resin. It is preferred that these are the coating weight of ^{0.1g / m 2 ~5.0g / m 2} . When it is 0.1 g / m ² or less, the heat insulating effect is small, and when it is larger than 5.0 g / m ² , the printing durability of the non-image area is deteriorated.

Although the lithographic printing plate precursor of the present invention can form an image by high-power laser exposure, a writing machine such as a thermal head may be used. In particular, in the present invention, it is preferable to use a laser that emits light in the infrared or near infrared region. A laser diode that emits light in the near infrared region is particularly preferable. In this case, it is necessary to carry out with an energy amount that can break the outer wall of the microcapsule contained in the heat sensitive layer. In addition, although recording with an ultraviolet lamp is possible, in the present invention, image exposure is preferably performed by a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 760 nm to 1200 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The energy applied to the recording material is preferably 10 to 300 mJ / cm ² .

The plate exposed in this way is attached to the cylinder of the printing press without processing. The plate attached in this way can be printed in the following procedure.
(1) Supplying dampening water to the printing plate and developing it on the machine, then supplying ink and starting printing. (2) Supplying dampening water and ink to the printing plate and developing on the machine There are a method of starting printing after printing, and (3) a method of supplying ink to the plate, supplying dampening water, and simultaneously supplying paper and starting printing. Further, as described in Japanese Patent No. 2938398, these plates are mounted on a printing machine cylinder, exposed by a laser mounted on the printing machine, and then dampened with water and / or ink. The image can be developed on top, and is preferably developable with water or an aqueous solution, or can be mounted on a printing machine and printed without being developed.

EXAMPLES Hereinafter, although this invention is demonstrated with an Example, this invention is not limited to these Examples.
Examples 1-6, Comparative Examples 1-3
Preparation of support (1) (preparation of aluminum substrate)
A molten metal of JIS A1050 alloy containing 99.5% or more of aluminum and Fe 0.30%, Si 0.10%, Ti 0.02%, and Cu 0.013% was subjected to a cleaning treatment and cast. In the cleaning process, a degassing process was performed to remove unnecessary gases such as hydrogen in the molten metal, and a ceramic tube filter process was performed. The casting method was a DC casting method. The solidified 500 mm thick ingot was chamfered 10 mm from the surface and homogenized at 550 ° C. for 10 hours so as not to coarsen the intermetallic compound. Next, after hot rolling at 400 ° C. and intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, cold rolling was performed to obtain an aluminum rolled plate having a thickness of 0.30 mm. By controlling the roughness of the rolling roll, the centerline average surface roughness Ra after cold rolling was controlled to 0.2 μm. Then, it applied to the tension leveler in order to improve planarity.

  Next, the surface treatment for making a lithographic printing plate support was performed. First, in order to remove the rolling oil on the surface of the aluminum plate, degreasing treatment was carried out with a 10% sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were carried out with a 30% sulfuric acid aqueous solution at 50 ° C. for 30 seconds.

Next, in order to improve the adhesion between the support and the heat-sensitive layer and to provide water retention to the non-image area, a so-called graining treatment was performed to roughen the surface of the support. While maintaining an aqueous solution containing 1% nitric acid and 0.5% aluminum nitrate at 45 ° C. and flowing an aluminum web through the aqueous solution, an alternating waveform with a current density of 20 A / dm ² and a duty ratio of 1: 1 by an indirect power supply cell Then, electrolytic graining was performed by giving an anode side electric quantity of 240 C / dm ² . Thereafter, etching treatment was performed with a 10% sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were performed with a 30% sulfuric acid aqueous solution at 50 ° C. for 30 seconds. (Aluminum substrate A)

Furthermore, in order to improve wear resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. An anodized film of 2.5 g / m ² by using a 20% sulfuric acid aqueous solution as an electrolyte at 35 ° C. and carrying out an electrolytic treatment with a direct current of 14 A / dm ² by an indirect power feeding cell while carrying an aluminum web into the electrolyte. It was created. (Aluminum substrate B)
Thereafter, a silicate treatment was performed in order to ensure hydrophilicity as a non-image portion of the printing plate. The treatment was carried with a 1.5% aqueous solution of sodium silicate 3 maintained at 70 ° C. so that the contact time of the aluminum web was 15 seconds and further washed with water. The adhesion amount of Si was 10 mg / m ² . Ra (center line surface roughness) of the support prepared as described above was 0.25 μm. (Aluminum substrate C)

Preparation of support (2) (preparation of support with exothermic hydrophilic layer provided on aluminum substrate)
Methanol silica sol (manufactured by Nissan Chemical Co., Ltd .: colloid consisting of methanol solution containing 30% by weight of silica particles of 10 nm to 20 nm) 45.2 g of methanol, 1.52 g of poly-2-hydroxyethyl methacrylate, infrared absorbing dye (I -32) 3.2 g was dissolved, and bar coating was performed on the aluminum substrate C obtained previously. It dried on 100 degree and 30 second conditions using oven. The coating amount was 1.0 g / m ² .

Preparation of support (3) (preparation of support with a heat-insulating layer on an aluminum substrate and a heat-generating hydrophilic layer)
Application of heat insulating layer 10 g of polyvinyl butyral resin was dissolved in 100 g of methyl ethyl ketone and 90 g of methyl lactate, and bar coating was performed on the aluminum substrate C obtained previously. It dried on 100 degree and 1 minute conditions using oven. The coating amount was 0.5 g / m ² .
Application of Exothermic Hydrophilic Layer Dissolve 45.2 g of methanol silica sol, 1.52 g of poly-2-hydroxyethyl methacrylate and 3.2 g of infrared absorbing dye (I-32) in 240 g of methanol. Bar coating was performed. It dried on 100 degree and 30 second conditions using oven. The coating amount was 1.0 g / m ² .

Synthesis of microcapsules whose outer wall is broken by the heat of synthesis of microcapsules (1)
As an oil phase component, 40 g of xylene diisocyanate, 10 g of trimethylolpropane diacrylate, 10 g of a copolymer of allyl methacrylate and butyl methacrylate (molar ratio 60/40), Pionein A41C (manufactured by Takemoto Yushi) were dissolved in 60 g of ethyl acetate. As an aqueous phase component, 120 g of a 4% aqueous solution of PVA205 (manufactured by Kuraray) was prepared. The oil phase component and the aqueous phase component were emulsified at 10,000 rpm using a homogenizer. Thereafter, 40 g of water was added, followed by stirring at room temperature for 30 minutes and further at 40 degrees for 3 hours. The microcapsule solution thus obtained had a solid content concentration of 20% and an average particle size of 0.5 μm.

Synthesis of microcapsules whose outer walls are broken by heat (2)
As oil phase components, 30 g of isophorone diisocyanate, 10 g of hexamethylene diisocyanate, 20 g of diethylene glycol diglycidyl ether, and 0.1 g of Pionine A41C (manufactured by Takemoto Yushi) were dissolved in 60 g of ethyl acetate. As an aqueous phase component, 120 g of a 4% aqueous solution of PVA205 (manufactured by Kuraray) was prepared. The oil phase component and the aqueous phase component were emulsified at 10,000 rpm using a homogenizer. Thereafter, 40 g of water was added, followed by stirring at room temperature for 30 minutes and further at 40 degrees for 3 hours. The thus obtained microcapsule liquid had a solid content of 20% and an average particle size of 0.7 μm.

Synthesis of particulate polymer that coalesces by heat (1) (comparative example) (no reactive group)
15 g of styrene and 200 ml of a polyoxyethylenephenol aqueous solution (concentration 9.84 × 10 ⁻³ mol·l ⁻¹ ) are added, and the system is replaced with nitrogen gas while stirring at 250 rpm. After the temperature of this liquid is 25 ° C., 10 ml of an aqueous cerium (IV) ammonium salt solution (concentration 0.984 × 10 ⁻³ mol·l ⁻¹ ) is added. At this time, an aqueous ammonium nitrate solution (concentration 58.8 × 10 ⁻³ mol·l ⁻¹ ) is added to adjust the pH to 1.3 to 1.4. This was then stirred for 8 hours. The liquid thus obtained had a solid content concentration of 9.5% and an average particle size of 0.4 μm.

Application of heat-sensitive layer Fine particles to be combined with the microcapsules of Synthesis Examples (1) and (2) and the heat of Synthesis Example (1) on the supports (1), (2) and (3) prepared as described above The coating liquid which consists of the following compositions each containing a shape polymer was created, and the heat sensitive layer was apply | coated.

Thermosensitive layer coating solution composition Water 70 g
1-methoxy-2-propanol 30 g
Synthesized microcapsules (1), (2), 5 g
Particulate polymer that coalesces by heat (1) (in terms of solid content)
Polyhydroxyethyl acrylate 0.5g
0.3 g of sulfate of p-diazodiphenylamine
Infrared absorbing dye (I-32) 0.3g

After the above liquid was applied by a bar, it was dried in an oven at 90 ° C. for 120 seconds. The coating amount was 0.5 g / m ² . The on-press developable lithographic printing plate thus obtained was output by a Creo Trendsetter 3244VFS equipped with a water-cooled 40 W infrared semiconductor laser, output 9 W, outer drum rotation speed 210 rpm, plate surface energy 100 mJ / cm ² , After exposure at a resolution of 2400 dpi, without being processed, it was attached to a cylinder of a printing machine Heidel SOR-M, dampening water was supplied, ink was supplied, paper was further supplied, and printing was performed. All plates could be developed on-press without problems and were printable. The number of printed materials obtained on each plate is shown in Table-1.

  From the above results, it was found that the lithographic printing plate having microcapsules in the heat-sensitive layer has better printing durability. In addition, a support having an exothermic hydrophilic layer provided on an aluminum substrate, or a support having an insulating layer provided on an aluminum substrate and further provided with an exothermic hydrophilic layer may have better printing durability. I understood. It was found that the microcapsules (1) and (2) whose outer walls are broken by heat upon laser irradiation have higher printing durability at the time of low energy exposure than the fine particle polymer (1) which is coalesced by heat.

Example 7
On the support (3), a thermosensitive layer coating solution comprising the following was applied.

70 g of water
1-methoxy-2-propanol 30 g
Synthesized microcapsule (1) (in terms of solid content) 5 g
Polyacrylic acid (weight average molecular weight 25000) 0.5g
Sorbitol triacrylate 1.0g
Infrared absorbing dye (I-31) 0.3g
0.3 g of t-butyldiphenyliodonium sulfate

  The plate thus obtained was subjected to the conditions of 250 mW per beam output, 800 rpm external drum rotation, and 2400 dpi resolution on a Luxel T-9000CTP manufactured by Fuji Photo Film Co., Ltd. equipped with a multichannel laser head. Exposed. When printing was performed in the same manner as in Examples 1 to 6, normal printing of 15000 sheets could be performed.

Example 8
On the support (3), a thermosensitive layer coating solution comprising the following was applied.

70 g of water
1-methoxy-2-propanol 30 g
Microcapsule (2) (in terms of solid content) 5 g
Polyacrylic acid (weight average molecular weight 25000) 0.5g
Diethylenetriamine 1.0g
Infrared absorbing dye (I-31) 0.3g
0.3 g of t-butyldiphenyliodonium sulfate

  The plate thus obtained was subjected to the conditions of 250 mW per beam output, 800 rpm external drum rotation, and 2400 dpi resolution on a Luxel T-9000CTP manufactured by Fuji Photo Film Co., Ltd. equipped with a multichannel laser head. Exposed. When printing was performed in the same manner as in Examples 1 to 6, normal printing of 30000 sheets could be performed.

Examples 9-11
The following microcapsules (3) and (4) were synthesized, and for a lithographic printing plate, as in Examples 1 to 6, except that a heat-sensitive layer coating liquid comprising the following was coated on the support (1). Preparation of the original plate, image exposure, and printing were performed.

Synthesis of microcapsules whose outer walls are broken by heat (3)
As an oil phase component, 40 g of xylene diisocinanaate, 9 g of trimethylolpropane diacrylate, 8 g of a copolymer of allyl methacrylate and butyl acrylate (molar ratio 60/40) 3 g of infrared absorbing dye (I-33), Pionine A41C (Takemoto Oil A) 0.1 g was dissolved in 60 g of ethyl acetate. As an aqueous phase component, 120 g of a 4% aqueous solution of PVA205 (manufactured by Kuraray) was prepared. The oil phase component and the aqueous phase component were emulsified at 10,000 rpm using a homogenizer. Thereafter, 40 g of water was added, and the mixture was stirred at room temperature for 30 minutes and further at 40 ° C. for 3 hours. The microcapsule liquid thus obtained had a solid content concentration of 20% and an average particle size of 0.6 μm.

Synthesis of microcapsules whose outer walls are broken by heat (4)
As an oil phase component, 40 g of xylene diisocinanaate, 9 g of trimethylolpropane diacrylate, 8 g of a copolymer of allyl methacrylate and butyl acrylate (molar ratio 60/40) 3 g of infrared absorbing dye (I-33), Pionine A41C (Takemoto Oil A) 0.1 g of 2,2′-azobisisobutyronitrile (1.0 g) was dissolved in 60 g of ethyl acetate. As an aqueous phase component, 120 g of a 4% aqueous solution of PVA205 (manufactured by Kuraray) was prepared. The oil phase component and the aqueous phase component were emulsified at 10,000 rpm using a homogenizer. Thereafter, 40 g of water was added, and the mixture was stirred at room temperature for 30 minutes and further at 40 ° C. for 3 hours. The microcapsule liquid thus obtained had a solid content concentration of 20% and an average particle size of 0.6 μm.

Thermosensitive layer coating solution of Example 9 70 g of water
1-methoxy-2-propanol 30 g
Synthesized microcapsule (3) 5 g
Polyhydroxyethyl acrylate 0.5g
p-diazodiphenylamine sulfate 0.3 g

Thermosensitive layer coating solution of Example 10 Water 70 g
1-methoxy-2-propanol 30 g
Synthesized microcapsule (3) 5 g
Polyhydroxyethyl acrylate 0.5g
Paradiazodiphenylamine sulfate 0.3g
Infrared absorbing dye (I-32) 0.1g

Heat-sensitive layer coating solution of Example 11 Water 70 g
1-methoxy-2-propanol 30 g
Synthesized microcapsule (4) 5 g
Polyhydroxyethyl acrylate 0.5g
Paradiazodiphenylamine sulfate 0.3g
Infrared absorbing dye (I-32) 0.1g

  In Examples 9 and 10, the number of printable sheets is 15000 sheets, the number of printable sheets in Example 11 is 25000 sheets, which is higher than that of Example 1 (9000 sheets) that does not contain a photothermal conversion substance in the microcapsules. A compound exhibiting printing durability and further promoting initiation of the reaction was placed in a microcapsule to further increase printing durability.

Examples 12-14
Except for using the aluminum substrates A to C obtained by the production process of the support (1), the lithographic printing plate precursor was prepared, image-exposed, and printed in the same manner as in Example 1, and its on-machine developability. Evaluated. The on-press developability was determined by observing how much the shadow portion of the dot of 150 lines / inch in the 100th printed material from the start of printing can be reproduced, and the higher the value, the better. The results are shown in Table-2 below.

  From Table 2 above, it was found that the use of an anodized aluminum substrate and further an silicate-treated aluminum substrate as the support was superior in on-press developability.

Claims (3)

  On the hydrophilic support, a heat-sensitive layer comprising a microcapsule containing a compound having a functional group whose outer wall is broken by the heat used for image formation and reacts by the heat is provided, and the photothermal conversion material is the heat-sensitive layer or its A lithographic printing plate precursor, which is contained in an adjacent layer.   2. The lithographic printing plate precursor as claimed in claim 1, wherein the hydrophilic support is an anodized aluminum substrate after a surface roughening treatment.   The lithographic printing plate precursor as claimed in claim 2, wherein the aluminum substrate is further subjected to a silicate treatment.