JP2000280642A - Heat sensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat sensitive lithographic printing plate capable of being directly engraved from digital data by image-like exposure of an infrared ray or the like by providing a hydrophilic heat sensitive layer having a crosslinked structure for crosslinking a polymer having an onium base changing from hydrophilicity into a lipophilicity by a heat and a crosslinkable group on a support. SOLUTION: A hydrophilic heat sensitive layer having a crosslinked structure for crosslinking a polymer having an onium base changing from hydrophilicity into a lipophilicity by a heat and a crosslinkable group is provided on a support. Then, the layer is formed by coating an upper surface of the support with the polymer having the onium base (thermally decomposable group) changing from the hydrophilicity into the lipophilicity by the heat and the crosslinkable group, and then reacting the crosslinkable group to give the crosslinked structure to the heat sensitive layer. The particularly effectively usable polymer has an ammonium base or preferably a pyridinium base as the onium (the decomposable group), and a photocrosslinkable group as the crosslinkable group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-sensitive lithographic printing plate, and more particularly to a heat-sensitive lithographic printing plate capable of obtaining a negative image by heat mode recording.

[0002]

2. Description of the Related Art Lithographic printing is a printing method using a printing plate having a lipophilic area (image area) capable of receiving ink and a hydrophilic area (non-image area) not capable of receiving ink. It is. Water or aqueous humidifier (fountain solution, etc.)
When both the ink and the ink are applied to a printing plate surface having hydrophilic and lipophilic areas, the hydrophilic areas are immersed in water or a humidifier, thereby becoming oleophobic, while the lipophilic areas become Accept ink. Such a lithographic printing plate has been obtained by performing image recording on a lipophilic ink-receiving resin layer provided on a hydrophilic support, and then dissolving and removing a non-image portion with a developing solution.

In the conventional plate making process from a lithographic printing plate precursor, a step of dissolving and removing a non-image portion after image recording is indispensable, and such additional wet processing is indispensable. This is a problem that has been desired to be improved over the prior art. Particularly in recent years, consideration for the global environment has become a major concern of the entire industry. The simplification of the treatment, the dry treatment, and the no treatment are more strongly desired than ever from the viewpoint of both the environmental aspect and the rationalization. In recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread, and various new image output methods corresponding to such digitization techniques have been put to practical use. It became like. Along with this, computer-to-plate technology that manufactures printing plates directly by scanning actinic radiation having a high directivity such as laser light in accordance with digitized image information has been eagerly desired. Obtaining a master version is an important technical issue.

On the other hand, a method using a solid-state laser, such as a semiconductor laser or a YAG laser, has become promising as a method of making a printing plate for recording an image by scanning exposure. In the high power density exposure system using these high power lasers, various phenomena different from the photoreaction used in the conventional photosensitive material system for low to medium power density exposure can be used. Usually, a recording method using such high power density exposure is called heat mode recording. In a high power density exposure system, the light energy absorbed by the photosensitive material is often converted into heat, and it is believed that the generated heat causes a desired phenomenon.

A great advantage of such a heat mode recording method is that fixing of an image after exposure is not essential. That is, the phenomenon used for image recording of the heat mode photosensitive material is as follows.
Fixation of the image after exposure is not essential, since exposure to light of normal intensity and under normal environmental temperatures do not occur substantially. For example, JP-A-10-296895 discloses an infrared-sensitive material obtained by reacting a monomer having a quaternary ammonium group on a hydrophobic support crosslinked as a surface hydrophilic substance.

[0006] However, Japanese Patent Application Laid-Open No. H10-296
The technique of the infrared-sensitive material described in Japanese Patent No. 895 does not require any special treatment after writing an image, but has a quaternary ammonium group after applying the photopolymerizable composition on a support in production. In order to impart hydrophilicity to the monomer by graft polymerization, it is necessary to perform a step of irradiating ultraviolet rays in an aqueous solution of a monomer having an ammonium group, and a step of performing graft polymerization and washing with running water. And the printing performance is not disclosed.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to overcome the drawbacks of the prior art and to make a plate directly from digital data by imagewise exposure such as infrared rays. An object of the present invention is to provide a heat-sensitive lithographic printing plate which does not require special treatment such as rubbing and has no problem in production. Another object of the present invention is to
An object of the present invention is to provide a heat-sensitive lithographic printing plate which is excellent in printing durability and excellent in printing performance in which non-image portions are not stained.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be achieved by the following heat-sensitive lithographic printing plate, and have completed the present invention. That is, the present invention provides a heat-sensitive lithographic printing plate having a hydrophilic heat-sensitive layer having a cross-linked structure obtained by cross-linking a polymer having a cross-linkable group and an onium base that changes from hydrophilic to lipophilic by heat on a support. is there.

The heat-sensitive lithographic printing plate of the present invention has a hydrophilic heat-sensitive layer having a cross-linked structure obtained by cross-linking a polymer having an onium base which changes from hydrophilic to lipophilic by heat and a cross-linkable group. Plates can be made directly from digital data by direct heating with a thermal head or imagewise exposure such as infrared light, and can be used directly on a printing machine without further wet development or rubbing after laser image exposure recording. it can. Further, since the hydrophilic heat-sensitive layer has a crosslinked structure, the heat-sensitive lithographic printing plate having excellent printing durability and excellent printing performance in which no non-image portion is stained can be obtained. Further, such a heat-sensitive lithographic printing plate includes, for example, a polymer having an onium base (thermally decomposable group) that changes from hydrophilic to lipophilic by heat and a photocrosslinkable group on one surface of a support. After the application, the hydrophilic thermosensitive layer can be formed by crosslinking by exposure to ultraviolet light or the like, and can be produced without any production problems.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (Hydrophilic thermosensitive layer having a cross-linked structure obtained by cross-linking a polymer having an onium base and a cross-linkable group that changes from hydrophilic to lipophilic by heat) First, the heat-sensitive lithographic printing plate of the present invention is characterized by heat The hydrophilic thermosensitive layer having a cross-linked structure obtained by cross-linking a polymer having an onium base and a cross-linkable group that changes from hydrophilic to lipophilic will be described. The hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the invention has a property of changing from hydrophilic to lipophilic by heat and has a crosslinked structure. Such a hydrophilic thermosensitive layer is formed by applying a polymer having an onium base (a thermally decomposable group) that changes from hydrophilic to lipophilic by heat and a photocrosslinkable group on a support or the like, and then applying the light It is formed by reacting a crosslinkable group to give a crosslinked structure to the layer.

The polymer having an onium group (thermally decomposable group) which changes from hydrophilic to hydrophobic by heat required for the hydrophilic thermosensitive layer of the thermosensitive lithographic printing plate of the present invention, and a crosslinkable group include Although a polymer known in the literature can be used, a polymer that can be used particularly advantageously has an ammonium base, preferably a pyridinium base, as an onium group (thermally decomposable group), and a photocrosslinkable group as a crosslinkable group. Is a polymer having The photocrosslinkable group mainly includes a photoradical polymerizable group and a photodimerizable group. It is not preferable to use a heat-crosslinkable group as the crosslinkable group, because the heat-decomposable group is affected during heating for crosslinking.
Among the polymers required for the hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention, those particularly preferable in terms of production are polymers having a styrylpyridinium structure represented by the following general formula.

[0012]

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In the formula, R ₁ and R ₂ represent hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. When R ₁ and R ₂ represent an aryl group or a substituted aryl group, the aryl group includes a carbocyclic aryl group and a heterocyclic (hetero) aryl group. As the carbocyclic aryl group, those having 6 to 19 carbon atoms such as a phenyl group, a naphthyl group, an anthracenyl group and a pyrenyl group are used. Examples of the heterocyclic aryl group include a pyridyl group, a furyl group, and other quinolyl groups in which a benzene ring is fused, a benzofuryl group, a thioxanthone group, and a carbazole group. Things are used. When R ₁ and R ₂ represent an alkyl group or a substituted alkyl group, the alkyl group may be a linear, branched or cyclic carbon atom such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, a cyclohexyl group and the like. 1
To 25 are used.

When R ₁ and R ₂ are a substituted aryl group, a substituted heteroaryl group or a substituted alkyl group, examples of the substituent include an alkoxy group having 1 to 10 carbon atoms such as a methoxy group and an ethoxy group, a fluorine atom, and a chlorine atom. Atom, halogen atom such as bromine atom, trifluoromethyl group, halogen-substituted alkyl group such as trichloromethyl group, methoxycarbonyl group, ethoxycarbonyl group, t-butyloxycarbonyl group, p-chlorophenyloxycarbonyl group, etc. An alkoxycarbonyl group or an aryloxycarbonyl group having 2 to 15 carbon atoms; a hydroxyl group; an acyloxy group such as an acetyloxy group, a benzoyloxy group, a p-diphenylaminobenzoyloxy group; a carbonate group such as a t-butyloxycarbonyloxy group; t-butyloxycarbonyl Ether groups such as tyloxy group and 2-pyranyloxy group; substituted and unsubstituted amino groups such as amino group, dimethylamino group, diphenylamino group, morpholino group and acetylamino group; thioether groups such as methylthio group and phenylthio group; vinyl An alkenyl group such as a group or styryl group; a nitro group; a cyano group; an acyl group such as a formyl group, an acetyl group or a benzoyl group; an aryl group such as a phenyl group or a naphthyl group; and a heteroaryl group such as a pyridyl group. be able to. When R ₁ and R ₂ are a substituted aryl group or a substituted heteroaryl group, alkyl groups such as a methyl group and an ethyl group can be used as the substituent in addition to the above.

Among the above, particularly preferred as R ₁ and R ₂ are aryl groups substituted with electron-withdrawing groups such as halogen, cyano and nitro, and electron-withdrawing groups such as halogen, cyano and nitro. An alkyl group, a secondary or tertiary branched alkyl group, and a cyclic alkyl group.
Hereinafter, specific examples of the polymer having a styrylpyridinium structure represented by the general formula will be described. However, the present invention is not limited to this specific example.

[0016]

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In the present invention, the polymer having an onium base (pyrolysable group) which changes from hydrophilic to lipophilic by heat and a crosslinkable group is based on the total solid content of the hydrophilic thermosensitive layer of the thermosensitive lithographic printing plate. , 5 to 100% by weight, more preferably 30 to 100% by weight. If the content is less than 30% by weight, discrimination of an image may be deteriorated.

Next, the above-mentioned polymer is photocrosslinked by ultraviolet exposure or the like to form a hydrophilic thermosensitive layer having a crosslinked structure, and then the mechanism of changing from hydrophilic to lipophilic by heat is described in the following reaction scheme. It will be explained in.

[0019]

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When a hydrophilic thermosensitive layer coating containing a polymer having a functional group (ethylene group) and an onium group (pyridinium base) capable of photodimerization is applied to a support or the like and exposed to light, the side chains of different polymer molecules differ from each other. The ethylene groups in the above form a photodimerization reaction to form a crosslinked portion of a cyclobutene structure. When the crosslinked layer is further heated, the hydrophilic pyridinium salt is decomposed by heat and changes to lipophilic pyridine.

The heat-sensitive lithographic printing plate of the present invention can record an image directly by heat using a heat-sensitive head or the like.
It is preferable to perform image recording by an exposure recording method by providing a layer containing a substance capable of converting light into heat (hereinafter, also referred to as a light-to-heat conversion material) on the support. The light-to-heat conversion material may be contained in the hydrophilic heat-sensitive layer, and as another intermediate layer between the support and the hydrophilic heat-sensitive layer, a light-to-heat conversion layer composed of a light-to-heat conversion material and a binder is provided. May have.

[Light-to-heat conversion material] As a light-to-heat conversion material to be contained in the hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention together with the above-mentioned polymer, it absorbs light such as ultraviolet light, visible light, infrared light, white light and the like. Any substance can be used as long as it can be converted into, for example, carbon black, carbon graphite, pigment, phthalocyanine pigment, iron powder, graphite powder, iron oxide powder, lead oxide, silver oxide, chromium oxide, iron sulfide, chromium sulfide, etc. Is mentioned. Particularly preferred is a wavelength 760
a dye that effectively absorbs infrared rays from nm to 1200 nm,
Pigment or metal.

As the dye, commercially available dyes and known dyes described in literatures (for example, "Dye Handbook" edited by The Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, and dyes such as metal thiolate complexes. Preferred dyes include, for example, JP-A-58-125246.
JP-A-59-84356, JP-A-59-2028
29, JP-A-60-78787, JP-A-58-173696, and JP-A-5-173696.
Methine dyes described in JP-A-8-181690 and JP-A-58-194595;
JP-A-58-224793, JP-A-59-481
No. 87, JP-A-59-73996, JP-A-60-52
No. 940, JP-A-60-63744 and the like, naphthoquinone dyes described in JP-A-58-112792 and the like, British Patent 434
No. 875, and the like.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924 is also used. JP-A-57-142645 (U.S. Pat. No. 4,327,169) describes a trimethinethiapyrylium salt described in JP-A-58-181051, and JP-A-58-181051, and JP-A-58-181051.
Nos. 8-220143, 59-41363 and 59-
No. 84248, No. 59-84249, No. 59-146
Nos. 063 and 59-146061; cyanine dyes described in JP-A-59-216146; pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475; Fairness 5-135
Nos. 14 and 5-19702 are also preferably used.

Examples of other preferred dyes include those represented by formulas (I) and (I) described in US Pat. No. 4,756,993.
Mention may be made of near-infrared absorbing dyes described under I). Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Among these, a water-soluble dye substituted with a hydrophilic group is preferable. Specific examples (compound 1) to (compound 15) of the hydrophilic near-infrared absorbing dye among the above-mentioned light-to-heat conversion materials are shown below, but the present invention is not limited thereto.

[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
Can be used. The types of pigments include black pigment, yellow pigment, orange pigment, brown pigment,
Red pigment, purple pigment, blue pigment, green pigment, fluorescent pigment,
Metal powder pigments and other polymer-bound dyes can be used.
Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Preferred among these pigments is carbon black.

These pigments may be used without surface treatment, or may be used after surface treatment. Examples of the surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a method of bonding a reactive substance (for example, a silane coupling agent, an epoxy compound, or a polyisocyanate) to the pigment surface. Conceivable. The above surface treatment methods are described in “Properties and Applications of Metallic Soap” (Koshobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). I have.

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Pigment particle size 0.01μ
If it is less than m, it is not preferable in terms of stability of the dispersion in the coating solution for the hydrophilic thermosensitive layer, and if it exceeds 10 μm, it is not preferable in terms of uniformity of the hydrophilic thermosensitive layer. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Dispersers include ultrasonic disperser, sand mill, attritor, pearl mill, super mill, ball mill, impeller, desparser, K
Examples thereof include a D mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

These dyes or pigments are used in an amount of 0.01 to 80% by weight, preferably 0.1 to 50% by weight, more preferably 1.0 to 30% by weight of the total solids of the hydrophilic thermosensitive layer composition. Can be used in proportions. If the content is more than 80% by weight, the non-image area is undesirably stained during printing. The concentration of the hydrophilic thermosensitive layer when using the above photothermal conversion material should be at least 0.3, preferably 0.5, more preferably 1.0 or more in terms of optical density (OD) at the exposure wavelength. . However, the OD at this time is a value when the hydrophilic thermosensitive layer composition is applied to a transparent support and measured by transmission.

The light-to-heat conversion material may be contained in a light-to-heat conversion layer provided as an intermediate layer between the support and the hydrophilic heat-sensitive layer. The light-to-heat conversion layer can be provided as an evaporation layer when the light-to-heat conversion agent is a metal. In other cases, it can be dissolved or dispersed in a suitable binder. The polymer binder for the light-to-heat conversion layer is preferably hydrophobic, and examples thereof include cellulose esters (eg, cellulose acetate, cellulose nitrate), copolymers of vinylidene chloride and acrylonitrile, poly (meth) acrylate, polyvinyl chloride, and the like. preferable. The polymer binder in the recording layer is preferably heat-sensitive, for example, a polymer containing a nitrate ester group (for example, GB-136398 and DE-A-25).
Preferred is a self-oxidizing binder cellulose nitrate disclosed in No. 12038), a polymer containing a carbonate group (such as a polyalkylene carbonate), or a polymer containing a covalent chlorine (such as polyvinylidene chloride).

[Water-insoluble particles] The hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention may contain the following water-insoluble particles in order to enhance the hydrophilicity. At least one kind of water-insoluble particles (hereinafter, also simply referred to as solid particles) selected from inorganic particles, organic particles and metal particles used in the present invention will be described. The solid particles have good affinity and adhesion to the above-mentioned crosslinked binder, and particles that improve the water retention are preferable as particulate matter. Particles surface-treated to improve dispersibility may be used. These inorganic particles, metal particles and organic particles may be used in appropriate combination.

The inorganic particles include, for example, metal oxides such as zinc oxide, titanium dioxide, iron oxide, and zirconia; silicic anhydride, hydrous calcium silicate, and hydrous aluminum silicate, which themselves have no absorption in the visible region. Silicon-containing oxides also called carbon; clay mineral particles such as clay, talc, kaolin, and fluorite can be used. As the metal particles, for example, aluminum, copper,
Nickel, silver, iron and the like can be used. The inorganic particles or metal particles are 10 μm or less, preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm, and still more preferably 1 to 5 μm.
m. When the average particle diameter of the inorganic particles or the metal particles is less than 0.01 μm, the water-retention of the laser-irradiated portion becomes insufficient, and the background stain is easily generated. If it exceeds 10 μm, the resolution of the printed matter will be poor, the adhesion to the support will be poor, and particles near the surface will be easily removed.

The inorganic particles or metal particles are contained in the recording layer in an amount of 2 to 90% by volume, preferably 5 to 80% by volume, more preferably 10 to 50% by volume based on the total composition. When the content of the particles is less than 2% by volume, water retention becomes insufficient at the laser-irradiated portion on the surface of the hydrophilic thermosensitive layer,
Background dirt is likely to occur. If the content exceeds 50% by weight, the strength of the recording layer is reduced and the printing durability is reduced, and the adhesion between the support and the recording layer is reduced. Organic particles other than inorganic particles or metal particles can be used as the granular material. The organic particles are not particularly limited as long as they enhance water retention, but resin particles can be used as the organic particles in a granular form. The following precautions need to be taken during use: When a solvent is used to disperse the resin particles, it is necessary to select resin particles that do not dissolve in the solvent or to select a solvent that does not dissolve the resin particles. When dispersing the resin particles with the thermoplastic polymer and heat, it is necessary to select a material that does not melt, deform, or decompose due to the heat at the time of dispersing the resin particles.

Crosslinked resin particles can be preferably used to reduce these cautions. Organic particles are 0.01 to 10 μm, preferably 0.05 to 10 μm.
μm, more preferably 0.1-5 μm, even more preferably 1-5 μm. When the average particle size of the organic particles is less than 0.01 μm, the water-retention of the laser-irradiated portion becomes insufficient, and soiling is likely to occur. If it exceeds 10 μm, the resolution of the printed matter will be poor, the adhesion to the support will be poor, and particles near the surface will be easily removed. The organic particles are 2 to 90% by volume, preferably 5 to 80% by volume, more preferably 10 to 90% by volume based on the total composition.
It is contained in the recording layer in an amount of 50% by volume. If the content of the particles is less than 3% by volume, the water retention of the laser-irradiated portion on the surface of the recording layer will be insufficient, and the background stain will easily occur.
If the content exceeds 50% by weight, the strength of the recording layer is reduced and the printing durability is reduced, and the adhesion between the support and the recording layer is reduced.

As the organic particles, polystyrene particles (particle diameter: 4 to 10 μm), silicone resin particles (particle diameter: 2 to 4 μm)
m) and the like. Examples of the crosslinked resin particles include a microgel (particle diameter: 0.01 to 1 μm) composed of two or more ethylenically unsaturated monomers and a crosslinked resin particle composed of styrene and divinylbenzene (particle diameter: 4 to 10 μm).
m), crosslinked resin particles composed of methyl methacrylate and diethylene glycol dimethacrylate (particle diameter 4 to 10).
μm), that is, acrylic resin microgel, cross-linked polystyrene, cross-linked methyl methacrylate, and the like. These are emulsion polymerization, soap-free emulsion polymerization,
It is prepared by a general method such as a seed emulsion polymerization method, a dispersion polymerization method, and a suspension polymerization method.

It is also possible to prepare inorganic particles from a solution. For example, a metal lower alkoxide is added to a solvent such as ethanol, and inorganic particles containing the metal are obtained in the presence of water and an acid or alkali. The resulting inorganic particle solution can be added to a solvent-soluble thermoplastic polymer solution to form an inorganic particle dispersion. Alternatively, it is also possible to add the metal lower alkoxide to the thermoplastic polymer solution first and then add water and an acid or an alkali to obtain inorganic particles containing the metal. When inorganic particles are prepared by adding a metal lower alkoxide to a thermoplastic polymer precursor solution, a polymer / inorganic composite is obtained when the polymer precursor is converted into a thermoplastic polymer by heat. As the metal lower alkoxide, tetraethoxysilane, tetraethoxytitanium and the like can be used.

[Other Components] In the hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention, for example, a dye having a large absorption in a visible light region may be used as a coloring agent for an image. it can. Specifically, Oil Yellow # 10
1, oil yellow # 103, oil pink # 312,
Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black B
S, oil black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, crystal violet (CI42555), methyl violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI
42000), methylene blue (CI52015) and the dyes described in JP-A-62-293247. These dyes are preferably added because they discolor after laser exposure, and it is easy to distinguish between image areas and non-image areas. The amount of addition is 0.01 to 10% by weight of the total solid content of the hydrophilic thermosensitive layer-forming material.

The hydrophilic heat-sensitive layer in the heat-sensitive lithographic printing plate of the present invention is disclosed in Japanese Patent Application Laid-Open Nos.
Non-ionic surfactants as described in JP-A-8514, JP-A-59-121044, JP-A-4-14-2
An amphoteric surfactant as described in JP-A-3149 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearic acid, and polyoxyethylene nonyl phenyl ether. Specific examples of the amphoteric surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-
Examples thereof include carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine type (for example, trade name Amogen K, manufactured by Daiichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and the amphoteric surfactant in the hydrophilic thermosensitive layer material is 0.05 to
It is preferably 15% by weight, more preferably 0.1 to 5% by weight.

Further, a plasticizer is added to the hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention, if necessary, for imparting 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, oligomers and polymers of acrylic acid or methacrylic acid, and the like are used. In addition to these, epoxy compounds, vinyl ethers, phenol compounds having a hydroxymethyl group described in Japanese Patent Application No. 7-18120, phenol compounds having an alkoxymethyl group, and the like may be added. Further, another polymer compound may be added to improve the strength of the coating film.

The hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate of the present invention can be usually produced by dissolving or dispersing the above-mentioned components in water and coating the solution on a hydrophilic support or the above-mentioned intermediate layer. Depending on the polymer or light-to-heat conversion material used, it can be dissolved in a solvent or a coating solution is prepared using a solvent in combination. As the solvent used herein, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples thereof include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, toluene, water and the like. It is not limited to this. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1
５０50% by weight.

Various methods can be used for the coating, such as bar coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. Can be. The hydrophilic heat-sensitive layer of the heat-sensitive lithographic printing plate used in the method of the present invention is provided with a surfactant for improving coating properties, for example, a fluorine-based interface as described in JP-A-62-170950. An activator can be added. The amount of these additives is preferably from 0.01 to 1% by weight, more preferably from 0.1 to 1% by weight, based on the total solid content of the hydrophilic thermosensitive layer material.
0.5 to 0.5% by weight.

The hydrophilic thermosensitive layer is exposed to light and heated to
It exhibits a function of accepting ink.
The amount of coating on the support (solid
Min) is generally 5 mg / m^Two~ 50g / m^TwoIs preferred
And more preferably 50 mg / m ^Two-10 g / m^Two,
More preferably 0.1 g / m^Two~ 5g / m^TwoIt is. Paint
Cloth weight is 5mg / m^TwoIf less, the hydrophobicity becomes insufficient
50 g / m^TwoThe effect is improved even if it is applied beyond
However, it is not preferable because the sensitivity is lowered. Book
According to an embodiment of the invention, the thickness is between 0.01 μm and 30 μm.
m hydrophilic thermosensitive layers are used.

The heat-sensitive lithographic printing plate of the present invention may be in any form as long as it has the above-mentioned hydrophilic heat-sensitive layer, but is provided in a form in which the hydrophilic heat-sensitive layer is provided on a suitable support. You can also. The support used in the heat-sensitive lithographic printing plate of the present invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, plastic (eg, polyethylene, polypropylene, polystyrene, etc.)
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.), and paper or plastic film on which the above-mentioned metal is laminated or vapor-deposited.

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

The back of the support may be covered with
A light coat is provided. As such a back coat
Organic polymer compounds described in JP-A-5-45885 and
Or inorganic or organic compounds described in JP-A-6-35174
Metals obtained by hydrolysis and polycondensation of metal compounds
An oxide coating layer is preferably used. these
Among the coating layers, Si (OCH_Three)_Four, Si (OC_TwoH_Five)_Four, S
i (OC_ThreeH₇) _Four, Si (OC_FourH₉)_FourSuch as silicon al
Koxy compounds are inexpensive and readily available, and gold obtained from them
A coating layer of a metal oxide is particularly preferable because of its excellent hydrophilicity.

As described above, the heat-sensitive lithographic printing plate of the present invention can be prepared. This heat-sensitive lithographic printing plate is image-exposed by a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 760 nm to 1200 nm. In the present invention, it is not necessary to perform a melting process, and it is possible to mount a printing plate on a printing machine immediately after laser irradiation and perform printing, and it is not necessary to perform a heating process between a laser irradiation process and a printing process. It became. The planographic printing plate obtained by such a process is used for printing a large number of sheets by using an offset printing machine or the like.

[0052]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. (Example 1, two-layer structure type) Polymer P-1 (trademark: SP)
A liquid comprising P-H13, manufactured by Toyo Gosei Co., Ltd.) and 5 g of water was stirred to prepare a photocrosslinkable liquid. Next, this solution was applied on a light-to-heat conversion layer composed of carbon black and nitrocellulose using a rod bar 18, dried at 100 ° C. for 10 minutes, and irradiated with light using a UV lamp for 5 minutes to give a photocrosslinked hydrophilic material. A heat layer was prepared to obtain a heat-sensitive lithographic printing plate. The light-to-heat conversion layer composed of carbon black and nitrocellulose was coated on a PET support with a liquid composed of 5 g of carbon black (trade name: MHI black, # 5F357M, manufactured by Mikuni Dyestuffs Co., Ltd.), 10 g of nitrocellulose, and 50 g of methyl ethyl ketone. 14 and dried at 80 ° C. for 3 minutes. The thickness of the light-to-heat conversion layer after drying was 2 μm.

(Example 2, one-layer constitution type) Polymer P-1
(Trademark: SPP-H13, manufactured by Toyo Gosei Co., Ltd.), 5 g of water
Was stirred to prepare a photocrosslinkable liquid. Next, 0.2 g of an infrared-absorbing dye (trademark: NK-3508, manufactured by Nippon Kogaku Dyeing Co., Ltd.) was added to the liquid, and the liquid was dispersed. Apply using 18,
After drying at 100 ° C. for 10 minutes, the mixture was further irradiated with light using a UV lamp for 5 minutes to prepare a hydrophilic thermosensitive layer which was photocrosslinked and contained a light-to-heat conversion substance, thereby obtaining a heat-sensitive lithographic printing plate. (Examples 3 to 5, two-layer structure type) The same operation as in Example 1 was performed. However, the polymer P- in the coating solution in the hydrophilic thermosensitive layer
Instead of 1, polymers P-2, 3 and 4 were used. (Example 6, two-layer structure type) The same operation as in Example 1 was performed. However, 5 g of silica gel particles (trade name: Sycilia # 445, manufactured by Fuji Silysia K.K.) and 3 g of PVA were further added to the coating solution in the hydrophilic thermosensitive layer to prepare a sol-gel solution, which was used as a coating solution.

[Evaluation of Printing Performance] The heat-sensitive lithographic printing plates obtained in Examples 1 to 6 were imagewise exposed by a semiconductor laser emitting infrared rays having a wavelength of 838 nm. After exposure, the resulting plate is not developed and is directly used as a printing machine, Heidel SO
RM was attached and printing was performed. Each of the heat-sensitive lithographic printing plates was subjected to 2,000 printings, and in each case, a clear printed matter was obtained, and a good printed matter having no stain on the non-image area was obtained.

[0055]

As described above, according to the heat-sensitive lithographic printing plate of the present invention, a polymer having an onium base which changes from hydrophilic to lipophilic by heat and a crosslinkable group is crosslinked on a support. By having a hydrophilic thermosensitive layer with a cross-linked structure, direct heating can be performed from digital data by direct heating with a thermal head or imagewise exposure such as infrared rays,
After the laser image exposure recording, it can be used as it is on a printing machine without further performing a wet development process, a rubbing process or the like. Further, since the hydrophilic heat-sensitive layer has a crosslinked structure, there is an effect that a heat-sensitive lithographic printing plate excellent in printing durability and excellent in printing performance in which a non-image portion is not stained can be obtained. Further, the heat-sensitive lithographic printing plate is formed by applying a polymer having an onium group and a crosslinkable group that change from hydrophilic to lipophilic by heat on a support or the like, and then forming the polymer by exposure to ultraviolet light or the like. Therefore, it can be manufactured without manufacturing problems.

Claims (1)

[Claims] 1. A heat-sensitive lithographic printing plate having a hydrophilic heat-sensitive layer having a crosslinked structure in which a polymer having an onium base which changes from hydrophilic to lipophilic by heat and a crosslinkable group is crosslinked on a support.