JP2002301877A - Substrate for lithographic printing plate and original plate of lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for lithographic printing plate, constituted of a hydrophilic layer provided on an aluminum substrate and having a sufficient heat insulating property as well as hydrophilic property while excellent in adhesive property to the substrate and capable of forming an image without any contamination with a high sensitivity while being capable of forming a lithographic printing plate excellent in resistance to printing, and an original plate of the lithographic printing plate, provided on the substrate with a heat sensitive ink acceptive layer and high in a sensitivity while excellent in resistance to printing as well as contamination preventing property. SOLUTION: The original plate for lithographic printing plate is provided, on the aluminum substrate, with a hydrophilic layer containing (A) an amorphous oxide containing silicon and alkaline metal, (B) the crystalline oxide of at least an element selected from a group consisting of aluminum, silicon, titanium, tin, indium, zirconium and iron in the amount so that the solid constituent weight ratio [(A)/(B) is within 1-10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a support for a heat-sensitive lithographic printing plate and a lithographic printing plate precursor using the same.
More specifically, it is possible to record an image by infrared laser beam scanning exposure based on a digital signal, and to support a lithographic printing plate that can be mounted on a printing press and printed without developing the image recorded. TECHNICAL FIELD The present invention relates to a lithographic printing plate precursor which is excellent in printing durability, stain resistance and sensitivity and which can be developed on a machine using the same.

[0002]

2. Description of the Related Art As an image forming method for a printing plate, a heat-sensitive lithographic printing plate precursor in which a plate surface is divided into an ink-receptive lipophilic region and a hydrophilic region to form a plate, relates to various image forming methods. Technology has been proposed. One of the promising methods is a method using ablation in which a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser is used for exposure, and the exposed portion is heated with a photothermal conversion agent that converts light into heat, thereby causing decomposition and evaporation. It is. That is, a lipophilic ink-receiving layer is provided on a hydrophilic substrate, the ink-receiving layer is removed by ablation by heating, and the hydrophilic substrate surface is exposed.
This is a method of recording an exposed portion as a hydrophilic region. WO9
No. 8/40212 (EK) describes a recording material in which a photothermal conversion layer is provided in a layer adjacent to an aluminum substrate, a hydrophilic layer containing a metal oxide is provided thereon, and an ink receiving layer is provided thereon. I have. According to this configuration, by providing the light-to-heat conversion layer on the substrate side, the generated heat is diffused to the substrate to reduce the proportion of heat used for ablation, and to improve recording sensitivity. However, this method uses a hydrophilic film containing various organometallic compounds as a main component, and since there are many residual organic components in the film, the hydrophilicity is slightly lowered, and stains are easily generated in a non-image portion. In addition, the light-to-heat conversion layer is composed of oxide particles alone, has low adhesion to the lower layer of nitrocellulose, and when the number of printed sheets is large, the light-to-heat conversion layer having poor surface hydrophilicity is exposed, resulting in poor printing durability. was there.

As such a hydrophilic layer, for example, Japanese Patent Application Laid-Open No. 2000-221666 discloses a layer containing a water-dispersible filler or sodium silicate and colloidal silica.
In the examples of JP-A-00-229485, those containing porous inorganic particles, colloidal silica and sodium silicate, and JP-T-2000-500708, those in which various oxide particles are mixed with sodium silicate, Although each of them is described, all of them have a problem that the content of sodium silicate is low and the hydrophilicity and the film-forming property are not sufficient, so that the stain prevention property and the printing durability are inferior. In addition, WO 99/19143
Japanese Patent Application Publication (EK) discloses not only an ink receiving layer but also a hydrophilic layer (+ photothermal conversion agent) formed by a colloid containing a metal oxide. The hydrophilic layer of the embodiment forms a layer by mixing a metal oxide colloid into a resin, sol-gel, or the like, or dispersing it in a resin, but here, the idea of using sodium silicate as a main component is disclosed. It has not been.

[0004] The support used for the lithographic printing plate is often obtained by subjecting aluminum to anodic oxidation treatment or other surface treatment as described above. In addition, a synthetic resin plate such as PET may be used. A support made of a synthetic resin plate has problems such as a change in dimensions during printing, an image being shifted, being easily scratched, and poor printing durability. The support which has been subjected to surface treatment on aluminum is complicated to manufacture as described above,
Lithographic printing not only is expensive, but also has a so-called heat-sensitive recording layer that changes the laser light into heat using a light-to-heat conversion material, changes the material properties of the recording layer by the generated heat, and forms an image portion and a non-image portion. In the plate, the generated heat diffuses to the support, and the heat energy near the support does not work effectively for image formation, and the sensitivity is substantially lower than that of materials having low thermal conductivity such as resin. There was a problem.

The anodic oxide film formed on the aluminum support is useful from the viewpoint of suppressing thermal diffusion.
Applied Optics / Vol. 32, No
According to 1/1 January (1993), it is known that the thermal conductivity is 1/20 to 1/30 as compared with ceramic alumina having good crystallinity because of low crystallinity and voids. . When an aluminum plate having excellent dimensional stability is used for the support, this anodic oxide film is useful, but as a means for preventing thermal diffusion, it is necessary to form the anodic oxide film to a necessary and sufficient thickness of about 5 μm. However, there is a problem that power cost and production efficiency are reduced. In addition, although the hydrophilized layer according to the technology of each of the above publications has a cost advantage, when viewed comprehensively as a hydrophilized layer of a support for lithographic printing that satisfies printing durability, stainability, and sensitivity, an anodic oxide film is used. Was still insufficient. Therefore, it can be formed without performing anodizing treatment, and is suitable for a support,
At the present time, a technique for forming a hydrophilic layer having characteristics that have no practical problem has not been found yet.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for forming an anodic oxide film on an aluminum substrate without forming the anodic oxide film or making the anodic oxide film extremely thin.
Having a heat-insulating property and hydrophilic property, and forming a hydrophilic layer with excellent adhesion to the support substrate, it is possible to form a high-sensitivity, stain-free image, An object of the present invention is to provide a lithographic printing plate support capable of forming a lithographic printing plate having excellent properties. A further object of the present invention is to provide a recording layer comprising a heat-sensitive ink-receiving layer on the support, to form an image with high sensitivity, to improve printing durability and to prevent contamination of non-image areas. It is to provide an excellent lithographic printing plate precursor.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventor has made water glass mainly on an aluminum substrate.
It has been found that by providing a hydrophilic layer in which an appropriate amount of a metal oxide is mixed, a support having high film strength, excellent hydrophilicity and excellent heat insulating properties can be formed, and the present invention has been completed. Shichirochi, the lithographic printing plate support of the present invention, on an aluminum substrate,
(A) an amorphous oxide containing silicon and an alkali metal;
(B) aluminum, silicon, titanium, tin, indium,
A hydrophilic oxide containing a crystalline oxide of at least one element selected from the group consisting of zirconium and iron in such an amount that the solid content weight ratio of both ((A) / (B)) is in the range of 1 to 10; It is characterized by having a layer. Further, the lithographic printing plate precursor according to claim 2 of the present invention comprises, on an aluminum substrate, (A) a non-crystalline oxide containing silicon and an alkali metal, and (B) aluminum, silicon, titanium, tin, indium. , Zirconium, and a crystalline oxide of at least one element selected from the group consisting of iron in an amount such that the solid content weight ratio of both ((A) / (B)) is in the range of 1 to 10. A lithographic printing plate support having a hydrophilic layer is provided with an ink receiving layer, and at least one of the ink receiving layer and the hydrophilic layer contains a photothermal conversion agent.

According to the present invention, on an aluminum substrate,
(A) A hydrophilic layer containing an amorphous oxide containing silicon and an alkali metal, such as water glass, is provided. However, since this material is amorphous, it is difficult to conduct heat, and a sensitivity equivalent to that of an anodic oxide film is achieved. Yes, it is highly hydrophilic. Further, by using (B) a crystalline oxide of at least one element selected from the group consisting of aluminum, silicon, titanium, tin, indium, zirconium, and iron at a specific ratio, the film strength and film strength can be improved. Improved formability and water resistance can be achieved. Therefore,
According to the present invention, by providing this hydrophilic layer without forming an anodic oxide film, it is possible to achieve a stain prevention property, a printing durability, and a sensitivity improvement effect comparable to the case of forming an anodic oxide film having the same thickness. Can be formed, but the usual 0.5 μm (2 g / m
² ) When an anodic oxide film of about the thickness is formed and the hydrophilic layer of the present invention is further formed thereon, further improvement in printing durability and sensitivity can be realized. Further, by providing a heat-sensitive ink-receiving layer that is ablated by the heat of laser exposure, on a support provided with a hydrophilic layer having excellent heat insulating properties and a film forming property according to the above-described configuration, the heat insulating properties and hydrophilic properties are utilized. In addition, it has become possible to provide a lithographic printing plate precursor that is recordable with high sensitivity and has excellent non-image portion stain prevention properties and excellent printing durability.

[0009]

Embodiments of the present invention will be described below in detail. First, the configuration of the lithographic printing plate support will be described. The lithographic printing plate support of the present invention is provided with a hydrophilic layer containing a non-crystalline oxide containing silicon oxide and sodium oxide and crystalline oxide fine particles at a specific ratio on an aluminum substrate. Hereinafter, the configuration of the support of the present invention will be sequentially described.

[Hydrophilic layer] The lithographic printing plate support of the present invention comprises, on the aluminum substrate, (A) a non-crystalline oxide containing silicon and an alkali metal, (B) aluminum, silicon, titanium, A crystalline oxide of at least one element selected from the group consisting of tin, indium, zirconium and iron, in an amount such that the solid content weight ratio of both ((A) / (B)) is in the range of 1 to 10; Having a hydrophilic layer. This hydrophilic layer contains (A) a non-crystalline oxide containing silicon and an alkali metal, specifically, water glass as a main component. As the water glass, various commercially available water glasses can be used. For example, the sodium silicate No. 3 specified by JIS-K1408 (Osaka Sodium Silicate Co., Ltd.'s SiO ₂ content: 28 to 30% by weight, Na ₂ O content: 9 to 10% by weight,
Water glass such as lithium silicate and potassium silicate can be used in the same manner as Nippon Chemical Industry Co., Ltd. (SiO ₂ content: 28 to 30% by weight, Na ₂ O content: 9 to 10% by weight).

As the component (A), for example, a film obtained by a so-called sol-gel method having an addition reactive group and a hydrophilic group using an organic silicone compound described in JP-A-9-236911 is also non-crystalline. It is an oxide and can be applied to the hydrophilic layer of the present invention. However, the organic component tends to remain in the film obtained by the sol-gel method, and therefore the hydrophilicity is slightly lowered. As the component (A) of the present invention, the water glass is more preferable. This (A) amorphous oxide containing silicon and an alkali metal is described later in (B)
It contains crystalline oxide fine particles of at least one element selected from the group consisting of aluminum, silicon, titanium, tin, indium, zirconium, and iron, and functions as a matrix of a hydrophilic layer. 1 to 10 times the solid content weight of the oxide fine particles.

In the present invention, the term "crystalline" means a compound which shows a clear peak in an X-ray diffractometer or an electron beam diffractometer, and the term "non-crystalline" means that a clear peak is not observed in those devices. Means substance. Generally, a metal oxide having higher crystallinity has a higher hardness, and it can be said that it is desirable as the component (B) described later. (B) aluminum, silicon,
Titanium, tin, indium, zirconium, crystalline oxide of at least one element selected from the group consisting of iron, specifically, aluminum, silicon, titanium, tin, indium, zirconium, selected from iron It refers to a crystalline oxide of at least one element, and when added, is preferably in the form of fine particles. The size of the fine particles is preferably in the range of 0.01 μm to 3 μm, more preferably in the range of 0.05 μm to 2 μm, and most preferably in the range of 0.1 μm to 1 μm. As a specific example of such a metal oxide fine particle, a commercially available reagent can be used. For example, a reagent [aluminum oxide (particle diameter 0.0
6 μm), indium oxide (particle diameter 1 μm), silicon dioxide (particle diameter 0.8 μm), zirconium oxide (particle diameter 1
μm), iron oxide (particle diameter 1 μm), titanium dioxide (particle diameter 1-2 μm), stannic oxide (particle diameter 1 μm)], and the like. Further, fine particles formed by a CVD method, a vapor deposition method, or the like can be used.

In the present invention, the above-mentioned (A) is added to the hydrophilic layer.
The non-crystalline oxide and (B) metal oxide fine particles
Weight ratio [(A) / (B)] in the range of 1 to 10
Must be contained in such an amount that: That is, the hydrophilic layer
When forming, determine the blending amount according to these weight ratios.
Just do it. These components in the already formed hydrophilic layer
The measurement of the solids ratio of the minute can be performed by the following method.
You. (A) Non-crystalline such as water glass used in the present invention
The oxide is generally SiO 2 _Two, K_TwoO, Na_TwoO, Li
O_TwoConsisting of non-crystalline oxides such as No. 3 silicate
In the case of_TwoAnd Na_TwoThe ratio of O is approximately 3: 1
It is. Since these oxides are non-crystalline, X-ray diffraction
Quantitative analysis is not possible with an XRD
Quantitative analysis is possible with an optical X-ray analyzer (XRF)
You. On the other hand, (B) the metal oxide fine particles have crystallinity.
X-ray diffraction analyzer (XRD) and X-ray fluorescence analysis
Quantitative analysis is possible with an apparatus (XRF). This property
(A) Acid derived from an amorphous oxide such as water glass
And fine metal oxide particles.

In the case where an overcoat layer is present, measurement may be performed after stripping with water or the like. For qualitative analysis of all elements, X-ray fluorescence spectroscopy (XRF) was used, and Na and Si
Is detected, in the case of No. 3 sodium silicate, S
i: Na = 3: 2, and when there are crystalline silica fine particles, the ratio of Si increases. Further, the presence of various oxide metal oxides can be confirmed. Qualitative analysis and quantitative analysis of various metal oxide fine particles are performed by an X-ray diffraction analyzer (XRD). For example, the hydrophilic layer composed of No. 3 sodium silicate and silicate fine particles can be quantitatively analyzed by an X-ray diffraction analyzer (XRD) and an X-ray fluorescence analyzer (XRF).

The water glass film has almost no crystallinity,
Although quantitative analysis cannot be performed by a X-ray diffraction analyzer (XRD), since the crystalline silica fine particles have crystallinity, quantitative analysis can be performed by X-ray diffraction. The total amount of silica can be quantitatively analyzed by an X-ray fluorescence analyzer (XRF). Therefore, the solid content of silica derived from water glass as the component (A) and the amount of the metal oxide fine particles (B) can be calculated by the following two formulas according to the following formula.

Solid content ratio = [SiO ₂ amount (XRF) + Na ₂ O amount (XRF) −SiO ₂ amount (XRD) −Na ₂ O amount (XRD)] / SiO ₂ amount (XRD) (Formula 1) Na _Since the amount of ₂ O (XRD) is hardly detected since Na ₂ O is derived from water glass, it is equivalent to the expression (2). Solid content = (SiO ₂ amount (XRF) + Na ₂ O amount (XRF) -SiO ₂ amount (XR D)) / SiO ₂ weight (XRD) method of quantifying (Equation 2) Quantitative analysis of water glass and colloidal oxide A predetermined amount of the substance or hydroxide is dropped and dried to prepare a standard sample for a calibration curve, and quantified by the calibration curve method. When there is an overcoat layer, measurement is performed after peeling with water or the like.

In the hydrophilic layer according to the present invention, in addition to the above essential components, various additives can be used in combination depending on the purpose. For example, for the hydrophilic layer, film strength and water resistance of the film,
Further, a resin having an aromatic hydroxyl group can be used for the purpose of improving image quality. As the resin having an aromatic hydroxyl group, a resin that dissolves in methanol in an amount of 5% by weight or more at 25 ° C. is preferable, and examples thereof include an alkali-soluble resin such as a novolak resin, a resol resin, a polyvinylphenol resin, and a ketone pyrogallol resin. Preferred novolak resins include phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, and at least one hydroxyl-containing aromatic compound selected from 3,5-xylenol and resorcinol,
At least one selected from aldehydes such as formaldehyde, acetaldehyde and propionaldehyde
Novolak resins that have been addition-condensed with a species under an acidic catalyst are mentioned. Instead of formaldehyde and acetaldehyde, paraformaldehyde and paraaldehyde, respectively, may be used.

Among them, m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol:
The mixing ratio of resorcinol is 40 to 100: 0 to 5 in molar ratio.
A mixture of 0: 0 to 20: 0 to 20: 0 to 20, or
A novolak resin which is an addition condensation product of a mixture of phenol: m-cresol: p-cresol at a molar ratio of 1 to 100: 0 to 70: 0 to 60 and an aldehyde is preferred. Of the aldehydes, formaldehyde is particularly preferred. The polystyrene-equivalent weight average molecular weight (hereinafter abbreviated as weight average molecular weight) of the novolak resin measured by gel permeation chromatography (hereinafter abbreviated as GPC) is preferably 1,000 to 15,000, and more preferably 1,500 to 10 , 000 are used.

Preferred resole resins include phenol, m-cresol, o-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, resorcinol, pyrogallol, bis- (4-hydroxyphenyl) methane, bisphenol -A, o-ethylphenol, m-ethylphenol, p-ethylphenol, propylphenol, n-butylphenol, t-
Hydroxy group-containing aromatic hydrocarbons such as butylphenol, 1-naphthol, and 2-naphthol, and at least one other polynuclear aromatic hydrocarbon having two or more hydroxyl groups are subjected to formaldehyde, acetaldehyde, propionaldehyde under an alkaline catalyst. And aldehydes such as benzaldehyde and furfural, and addition-condensation with at least one aldehyde or ketone selected from ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. Instead of formaldehyde and acetaldehyde, paraformaldehyde and paraaldehyde, respectively, may be used. The weight average molecular weight of the resole resin is preferably 500 to 1
It is particularly preferably from 1,000 to 5,000.

Preferred polyvinyl phenol resins include o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene and 2- (m-hydroxyphenyl)
Examples thereof include homopolymers of hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene, or copolymers of two or more thereof. Hydroxystyrenes may have a substituent such as a halogen such as chlorine, bromine, iodine or fluorine or an alkyl group having 1 to 4 carbon atoms on the aromatic ring. And a polyvinyl phenol which may have a halogen or an alkyl group having 1 to 4 carbon atoms. In addition, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl)
Those obtained by copolymerizing hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene with methacrylic acid, acrylic acid, alkyl methacrylate or alkyl acrylate are also useful.

The polyvinyl phenol resin is usually obtained by polymerizing hydroxystyrene, which may have a substituent, alone or in combination of two or more in the presence of a radical polymerization initiator or a cationic polymerization initiator. . Such a polyvinyl phenol resin may be partially hydrogenated. Further, a resin in which some hydroxyl groups of the polyvinyl phenol resin are protected by a t-butoxycarbonyl group, a pyranyl group, a furanyl group, or the like may be used. The weight average molecular weight of the polyvinyl phenol resin is preferably 1,0.
00 to 100,000, particularly preferably 1,500 to 5
000. As ketone pyrogallol resin,
Acetone pyrogallol resins are particularly useful. The proportion of the resin having an aromatic hydroxyl group to be added is 1 to 5% by weight, preferably 1 to 3% by weight based on the solid content of the hydrophilic layer.

Further, a hydrophilic resin may be added for the purpose of improving the film properties of the hydrophilic layer. As the hydrophilic resin, those having a hydrophilic group such as a hydroxyl group, a carboxyl group, a hydroxyethyl group, a hydroxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, a carboxymethyl group are preferable. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and their sodium salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymer, styrene-maleic acid copolymer, polyacrylic acid and , Polymethacrylic acid and salts thereof, homopolymers and copolymers of hydroxyethyl methacrylate,
Homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers and copolymers of hydroxybutyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycol, polypropylene oxide , Polyvinyl alcohol, and a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight
Polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers, methacrylamide homopolymers and polymers, N-methylol acrylamide homopolymers and copolymers, and the like.

Particularly preferred hydrophilic resins are hydroxyl group-containing polymers, specifically, polyvinyl alcohol, silica-modified polyvinyl alcohol, homopolymers and copolymers of hydroxyethyl methacrylate and copolymers of hydroxyethyl acrylate.

When the hydrophilic resin is water-soluble, the proportion of the hydrophilic resin is preferably 10% by weight or less based on the solid content of the hydrophilic layer. Above that, the water resistance and surface quality of the coating are improved, but the good hydrophilicity of the water glass is impaired, which is not preferred. On the other hand, if the content is less than 0.1% by weight, the film-forming property is slightly deteriorated, and after drying, the film is apt to crack, which may lead to a reduction in printing durability. More preferably, the content is in the range of 0.1 to 3% by weight.

The hydrophilic layer of the present invention may contain a crosslinking agent for promoting the crosslinking of the colloidal oxide or hydroxide. Examples of such a crosslinking agent include an initial hydrolysis condensate of tetraalkoxysilane, trialkoxysilylpropyl-N, N, N-trialkylammonium halide,
Alternatively, aminopropyl trialkoxysilane is preferred. The addition ratio is preferably 5% by weight or less of the solid content of the hydrophilic layer.

Further, for the purpose of increasing the printing durability during printing, a crosslinking agent for the above-mentioned hydrophilic resin or resin having an aromatic hydroxyl group may be added. Examples of such a crosslinking agent include formaldehyde, glyoxal, polyisocyanate, an initial hydrolysis / condensation product of tetraalkoxysilane, dimethylol urea, and hexamethylol melamine. Further, in the hydrophilic layer of the present invention,
In order to improve the surface condition of the coating, a well-known fluorine-based surfactant, silicon-based surfactant, or polyoxyethylene-based surfactant may be added.

The coating thickness (after drying) of the hydrophilic layer of the present invention is 1
It is preferably from 10 to 10 μm. More preferably 3 to
5 μm. Within this range, the heat insulating property and durability of the hydrophilic layer are secured, and good printing durability during printing is obtained. (Method of Measuring Film Thickness of Hydrophilic Layer) The film thickness of the hydrophilic layer can be measured using an ultra-high resolution SEM (Hitachi S-900). In the present invention, the aluminum support with the hydrophilic layer is bent at a relatively low accelerating voltage of 12 V and subjected to a vapor deposition treatment or the like for imparting conductivity, and then the side surface of a crack generated when the bending is performed ( (Commonly known as fracture surface)
Are measured using an ultra-high resolution SEM (Hitachi S-900). The fractured surface was observed at an appropriate magnification of 10,000 to 50,000 times, and the thickness was randomly extracted and measured at ten places, and the average value was used. The standard deviation error was less than ± 10%.

[Overcoat layer] The support for the heat-sensitive lithographic printing plate of the present invention may have a water-soluble overcoat layer on the hydrophilic layer. The overcoat layer can prevent the lipophilic substance from contaminating the hydrophilic layer and damaging the hydrophilic layer during storage and handling of the support. Also, by including a photothermal conversion agent in the overcoat layer,
It is possible to increase the sensitivity. Thus, the method of increasing the sensitivity of adding the photothermal conversion agent to the overcoat layer is higher than the method of increasing the sensitivity of adding a large amount of the photothermal converter to the hydrophilic layer,
This is a preferable embodiment because there is little possibility of deteriorating the hydrophilicity and film quality of the hydrophilic layer and the same effect can be expected.

The water-soluble overcoat layer that can be used in the present invention is preferably easily removable at the time of printing, and therefore contains a resin selected from water-soluble high molecular compounds. As the water-soluble polymer compound used here, a film formed by coating and drying has a film-forming ability, and specifically, polyvinyl acetate (provided that the hydrolysis rate is 6%).
5% or more), polyacrylic acid and its alkali metal salt or amine salt, acrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, methacrylic acid copolymer And alkali metal salts or amine salts thereof, acrylamide homopolymers and copolymers, polyhydroxyethyl acrylate, vinylpyrrolidone homopolymers and copolymers, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly- 2-acrylamido-2-methyl-1-propanesulfonic acid and its alkali metal salt or amine salt, 2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic,
Fibrin derivatives (eg, carboxymethylcellulose,
Carboxyethylcellulose, methylcellulose and the like) and modified products thereof, white dextrin, pullulan, enzymatically decomposed etherified dextrin and the like. Further, according to the purpose, two or more of these resins can be used in combination.

In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution application for the purpose of ensuring uniformity of application. Specific examples of such a nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearate, polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl ether, and the like. . The proportion of the nonionic surfactant in the total solid content of the overcoat layer is preferably 0.05 to 5% by weight, and more preferably 1 to 3% by weight.

The thickness of the overcoat layer according to the present invention is set to 0.1.
It is preferably from 0.1 to 0.5 μm, more preferably from 0.1 to 0.5 μm.
０．３0.3 μm. Within this range, it takes time to remove the overcoat layer during printing, or a large amount of dissolved water-soluble resin affects the dampening solution, causing roller strips during printing, and ink depositing on the image area. Good prevention of scattering of ablation scum and prevention of lipophilic substance contamination can be obtained without giving any adverse effects such as no abrasion and without impairing the film properties.

[Support Substrate] As the raw aluminum substrate used for the aluminum support of the present invention, an aluminum plate which is a conventionally known material can be appropriately used. The aluminum substrate referred to in the present invention includes a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of a different element. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is preferably 10% by weight or less. In addition, any one of an aluminum plate made from an ingot by the DC casting method and an aluminum plate made from the ingot by the continuous casting method can be used as the support substrate of the present invention.

The thickness of the aluminum substrate used in the present invention is 0.05 to 0.6 mm, preferably 0.1 to 0.6 mm.
It is 0.4 mm, particularly preferably 0.15 to 0.3 mm.

Prior to anodizing the aluminum plate, it is preferable to roughen the surface. Roughening can increase the surface area and improve the adhesion to the upper layer. The surface roughening treatment of the aluminum plate surface is performed by various methods. For example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of selectively dissolving the surface chemically. It is performed by a method or a combination of two or more of these methods. As a mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used. As a chemical method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A-54-31187 is suitable. Further, as an electrochemical surface roughening method, there is a method of carrying out an alternating current or a direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Also, Japanese Patent Application Laid-Open No. 54-6390
An electrolytic surface roughening method using a mixed acid as described in No. 2 can also be used. The surface roughening by the above-mentioned method is performed by using the center line average roughness (Ha) of the aluminum plate surface.
Is preferably applied in the range of 0.3 to 1.0 μm.

The roughened aluminum plate is preferably subjected to an alkali etching treatment with an aqueous solution of potassium hydroxide or sodium hydroxide, if necessary, further subjected to a neutralization treatment, and then to an anodic oxidation treatment. Moreover, in the present invention, since the hydrophilic layer described later has excellent hydrophilicity and heat insulating properties, it is possible to provide an inexpensive plate by omitting the anodic oxidation treatment described below.

As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, sulfamic acid, Benzenesulfonic acid,
Alternatively, their mixed acids are used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte. Anodizing treatment conditions vary depending on the electrolyte to be used, and thus cannot be specified unconditionally.
80% by weight solution, liquid temperature 5 to 70 ° C, current density 5 to 60
A / dm ² , voltage 1 to 100 V, electrolysis time 10 seconds to 50
A range of minutes is appropriate. Among these anodizing treatments, in particular, a method of anodizing with high current density in sulfuric acid described in British Patent No. 1,412,768 and US Pat. No. 3,511,661 are described. A method of performing anodic oxidation using phosphoric acid as an electrolytic bath is preferable.

In the present invention, when an anodic oxide film is provided on an aluminum substrate, the amount of the film is 2.0 g / g.
m ² or more, preferably 2.0 to
6.0 g / m ² , more preferably 2.0 to 2.0 g / m ^2.
It is in the range of 5.0 g / m ² .

In the present invention, after the distribution density of the micropores is adjusted by optimizing the anodic oxidation conditions, treatment with an aqueous acid or alkali solution (pore widening treatment) for the purpose of expanding the size of the micropores may be performed. preferable. In this treatment, the aluminum substrate on which the anodic oxide film is formed is immersed in an aqueous acid or alkali solution, and the anodic oxide film is preferably treated at 0.05 to 20 g / m 2.
² , more preferably 0.1 to 5 g / m ² , particularly preferably 0.2 to 4 g / m ² .

The following conditions are desirable as processing conditions for obtaining the above-mentioned film dissolution amount. As a specific condition range, when treating with an aqueous acid solution, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid or phosphoric acid or a mixture thereof, and the concentration is preferably 10 to 500 g /
l, more preferably 20 to 100 g / l, and the temperature is preferably 10 to 90 ° C, more preferably 40 to 7 ° C.
0 ° C., the immersion time is preferably 10 to 300
Seconds, more preferably 30 to 120 seconds. On the other hand, when treating with an alkaline aqueous solution, it is preferable to use an aqueous solution of sodium hydroxide, potassium hydroxide, lithium hydroxide, or a mixture thereof, and the pH of the aqueous solution is preferably 9 to 13, more preferably 11.5
To 12.5, and the temperature is preferably 10 to 9
0 ° C, more preferably 30 to 50 ° C, and the immersion time is preferably 1 to 300 seconds, more preferably 5 to 3 seconds.
0 seconds. Within this range, good pore widening can be achieved without significantly shortening the time required to dissolve and reducing the working efficiency, or dissolving in an extremely short time and preventing practical control. Can be processed.

When the aluminum substrate having the anodic oxide film has been subjected to the pore widening treatment, the aluminum substrate can be subjected to a sealing treatment later. The sealing treatment to be applied is performed using a known method such as hot water treatment, boiling water treatment, steam treatment, dichromate treatment, nitrite treatment, ammonium acetate treatment, and electrodeposition sealing treatment. Can be. As a method of hot water treatment, steam treatment or boiling water treatment, for example, JP-A-4-176690, 5-1.
There are many known examples such as 31773. Processing temperature is 9
About 5 to 200 ° C., preferably about 100 to 150 ° C., and the processing time is about 5 to 150 seconds at 100 ° C.
At 150 ° C., it is preferably about 1 to 30 seconds.

As another sealing treatment, JP-B-36-220
No. 63 or the like can be used. Alternatively, JP-A-9-244
No. 227, a method of treating with an aqueous solution containing a phosphate and an inorganic fluorine compound can be used. Further, the method of treating with an aqueous solution containing a saccharide described in JP-A-9-134002 can also be used.
In addition, Japanese Patent Application Nos. 10-252078 and 10-
The method of treating with an aqueous solution containing titanium and fluorine described in No. 253411 can be used.

As the sealing treatment, a treatment using an alkali metal silicate may be performed. In such a case, a method described in US Pat. No. 3,181,461 can be used. In the alkali metal silicate treatment, an alkali metal silicate aqueous solution having a pH of 10 to 13 at 25 ° C. which does not cause gelation of the solution and dissolution of the anodic oxide film is used. The sealing process can be performed by appropriately selecting processing conditions such as processing time. Suitable alkali metal silicates include sodium silicate, potassium silicate, lithium silicate and the like. Further, in order to adjust the pH of the alkali metal silicate aqueous solution to high, sodium hydroxide, potassium hydroxide,
Lithium hydroxide and the like can be blended.

If necessary, an alkaline earth metal salt or a Group IVB metal salt may be added to the aqueous alkali metal silicate solution. Examples of the alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and sulfates, hydrochlorides, phosphates, acetates, oxalates, and borates of these alkaline earth metals. And water-soluble salts such as salts. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, and the like. be able to. Alkaline earth metal salt or No.
Group IVB metal salts can be used alone or in combination of two or more. The preferred use amount range of these metal salts is 0.01 to 10% by weight, and the more preferred range is 0.05 to 5.0% by weight.

The lithographic printing plate support of the present invention thus obtained is excellent in hydrophilicity and heat insulating properties, and has good adhesion and strength. It can be suitably used as a support for an original plate.

[Lithographic printing plate precursor] The lithographic printing plate precursor according to the present invention is obtained by providing an ink receiving layer on the lithographic printing plate support. It is preferable from the viewpoint of recording sensitivity that at least one layer contains a photothermal conversion agent in each layer configuration such as an overcoat layer provided by the above.

[Ink Receiving Layer] The ink receiving layer used in the present invention contains an organic polymer compound and, if desired, further contains a photothermal conversion agent. The organic polymer compound is not particularly limited as long as it is soluble in a solvent and can form a lipophilic film. Among them, from the viewpoint of the stability of the layer, it is desirable to select a compound that is insoluble in the coating solvent of the hydrophilic layer or the overcoat layer, which is a layer provided adjacent to the layer. May be selected to swell in the coating solvent.In this case, it is expected that the adhesiveness with an adjacent layer such as a hydrophilic layer can be improved. What dissolves is undesirable.

Examples of useful organic polymer compounds include polyester, polyurethane, polyurea, polyimide, polysiloxane, polycarbonate, phenoxy resin, epoxy resin, novolak resin, resole resin, condensation resin of phenol compound and acetone, polyvinyl acetate, acrylic Resin and its copolymer, polyvinylphenol, polyvinylhalogenated phenol, methacrylic resin and its copolymer, acrylamide copolymer, methacrylamide copolymer, polyvinylformal, polyamide, polyvinylbutyral, polystyrene, cellulose ester resin, poly Examples thereof include vinyl chloride and polyvinylidene chloride. Among these, as a more preferable compound, a resin having a hydroxyl group, a carboxyl group, a sulfonamide group or a trialkoxysilyl group in a side chain is excellent in adhesion to a substrate or an upper hydrophilic layer, and in some cases, a crosslinking agent. It is desirable because it cures easily. In addition, an acrylonitrile copolymer, polyurethane, a copolymer having a sulfonamide group in a side chain or a copolymer having a hydroxyl group in a side chain, which is photocured with a diazo resin, is preferable.

As the novolak resin and resol resin, phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol Modified xylene, t-butylphenol, octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl,
p-Cl), bromophenol (m-Br, p-B
r), addition condensation products of salicylic acid, phloroglucinol and the like with aldehydes such as formaldehyde and paraformaldehyde.

Other suitable high molecular compounds include copolymers having the average molecular weight of usually from 100,000 to 200,000, containing the monomers shown in the following (1) to (12) as constituent units. (1) acrylamides having an aromatic hydroxy group,
Methacrylamides, acrylates, methacrylates and hydroxystyrenes such as N
-(4-hydroxyphenyl) acrylamide or N
-(4-hydroxyphenyl) methacrylamide, o
-, M- and p-hydroxystyrene, o-, m- and p-hydroxyphenyl acrylate or methacrylate, (2) acrylates and methacrylates having an aliphatic hydroxy group, for example,
2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, Acrylates such as phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N, N-dimethylaminoethyl acrylate,

(4) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
Amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid
Methacrylic acid esters such as 2-chloroethyl, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N, N-dimethylaminoethyl methacrylate;
(5) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide,
N-cyclohexylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenyl Methacrylamide, N-ethyl-N-phenylacrylamide and N-ethyl-
Acrylamide or methacrylamide such as N-phenylmethacrylamide,

(6) Ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and phenyl vinyl ether; (7) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate; (8) styrenes such as styrene, methyl styrene and chloromethyl styrene; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone;
(10) olefins such as ethylene, propylene, isobutylene, butadiene and isoprene; (11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc.

(12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) Naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Acrylamide or methacrylamides containing a sulfonamide group such as phenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide;
Further, o-aminosulfonylphenyl acrylate, m
-Aminosulfonylphenyl acrylate, p-aminosulfonylphenyl acrylate, 1- (3-aminosulfonylphenylnaphthyl) acrylate, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3 -Sulfonamide group-containing acrylates or methacrylates such as -aminosulfonylphenylnaphthyl) methacrylate.

These organic polymers can be dissolved in a suitable solvent, coated on the support and dried to form an ink receiving layer. At this time, only the organic polymer compound may be used by dissolving it in a solvent, but the ink receiving layer coating solution may further include a crosslinking agent, an adhesion auxiliary agent, a coloring agent, inorganic or organic fine particles, and a coating surface improvement. Agents and plasticizers can be added as needed. In addition, a heat coloring or decoloring additive for forming a printout image after exposure may be added.

Examples of the crosslinking agent for crosslinking the organic polymer compound include diazo resin, aromatic azide compound, epoxy resin, isocyanate compound, blocked isocyanate compound, initial hydrolysis condensate of tetraalkoxy silicon, glyoxal, aldehyde compound and the like. Methylol compounds can be mentioned.

As the adhesion aid, the above diazo resin is excellent in adhesion to the substrate and the hydrophilic layer. In addition, a silane coupling agent, an isocyanate compound, and a titanium coupling agent are also useful.

As the coloring agent, ordinary dyes and pigments are used. In particular, rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, quinizarin, 2- (α-naphthyl) -5- Phenyloxazole and the like. Specific examples of other dyes include Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green B
G, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet (CI
42555), methyl violet (CI4253)
5), ethyl violet, methylene blue (CI52
015), Patent Pure Blue (manufactured by Sumitomo Sangoku Chemical), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4-p-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc. Triphenylmethane series represented by
Diphenylmethane, oxazine, xanthene, iminonaphthoquinone, azomethine or anthraquinone dyes or JP-A-62-293247,
Dyes described in JP-A-9-179290 can be exemplified. When the above dye is added to the ink receiving layer, it is usually used in an amount of about 0.0
The proportion is 2 to 10% by weight, more preferably about 0.1 to 5% by weight.

Further, fluorine-based surfactants and silicon-based surfactants, which are well-known compounds as coating surface condition improvers, can also be used. Specifically, a surfactant having a perfluoroalkyl group or a dimethylsiloxane group is useful for preparing the coated surface.

In order to improve the recording sensitivity, a light-to-heat converting agent having a function of converting light into heat can be added to the ink receiving layer of the present invention. The light-to-heat conversion agent may be added to the layer structure of the lithographic printing plate precursor, for example, to the hydrophilic layer or the overcoat layer, or a light-to-heat conversion layer for the purpose of a light-to-heat conversion function may be provided. It can also be added. As the photothermal conversion agent that can be used in the present invention,
There is no particular limitation as long as it is a substance that absorbs light having an absorption band in at least a part of the range of 700 to 1200 nm and generates heat, and various infrared absorbing pigments or dyes can be used. As pigments, commercially available pigments and Color Index (CI) Handbook, “Latest Pigment Handbook”
Infrared absorbing pigments described in “Latest Pigment Application Technology” (CMC Publishing, 1986) and “Printing Ink Technology” (CMC Publishing, 1984) can be used. . These pigments can be used after being subjected to a known surface treatment, if necessary, in order to improve the dispersibility in the layer to which the pigment is added. Examples of the surface treatment include a method of surface-coating a hydrophilic resin or a lipophilic resin, a method of attaching a surfactant, and a reactive substance (eg, a silica sol, an alumina sol, a silane coupling agent, an epoxy compound, an isocyanate compound, and the like). Can be conceived on the surface of the pigment. When a light-to-heat conversion agent is added to a layer having a hydrophilic matrix such as a hydrophilic layer, the pigment to be used is, in particular, a hydrophilic resin or a silica sol so that it is easily dispersed with a water-soluble resin and does not impair the hydrophilicity. It is desirable that the surface is coated. The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm,
More preferably, it is in the range of 0.01 μm to 0.5 μm. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Among the pigments, a particularly preferred pigment is carbon black.

Examples of the dye include commercially available dyes and literatures (for example, "Near-Infrared Absorbing Dyes" in "Chemical Industry", May, 1986, p. , "Development of functional dyes and market trends in the 1990s", Chapter 2, section 2.3 (CMC, 1990)
Alternatively, known dyes described in patents can be used. Specifically, infrared absorbing dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, polymethine dyes, and cyanine dyes are preferred.
Further, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, and JP-A-58-173696.
JP-A-58-181690, JP-A-58-194
No. 595, etc., methine dyes described in JP-A-58-112793, JP-A-58-224793,
JP-A-59-48187, JP-A-59-73996
JP-A-60-52940, JP-A-60-6374
No. 4, No. 4, etc.
Squarylium dyes described in JP-A-112792, cyanine dyes described in British Patent No. 434,875, dyes described in U.S. Pat. No. 4,756,993, cyanine dyes described in U.S. Pat. No. 4,973,572, JP Hei 10
And dyes described in JP-A-268512.

As a dye, US Pat. No. 5,156,
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (U.S. Pat. No. 4,327,169), a trimethinethiapyrylium salt described in JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363
Nos. 59-84248, 59-84249, 59-146063, and 59-146061 and pyrylium compounds described in JP-A-59-2161.
No. 46, a cyanine dye disclosed in U.S. Pat. No. 4,283,4.
No. 75, pentamethine thiopyrylium salt and the like, and Japanese Patent Publication Nos. 5-135514 and 5-19702, and the like. Epolite I
II-130, Epolite III-125 and the like are also preferably used. Among these, a particularly preferred dye to be added to the overcoat layer and the hydrophilic layer is a water-soluble dye, and specific examples thereof are listed below by structural formulas.

[0061]

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[0062]

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[0063]

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The dye used when added to the ink receiving layer according to the present invention may be the above-mentioned infrared absorbing dye, but a more lipophilic dye is preferred from the viewpoint of uniformity. Preferred examples of the dye include the following cyanine dyes.

[0065]

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[0066]

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The proportion of the photothermal conversion agent varies depending on the thickness of the ink receiving layer, the presence or absence of the overcoat layer, and the infrared reflectance of the hydrophilic layer. 20% by weight or less is preferred,
The range is preferably 3 to 20% by weight, more preferably 5 to 15% by weight. Within this range, a good sensitivity improving effect can be obtained without impairing the durability of the ink receiving layer. Particularly, in a plate requiring printing durability, the thickness of the ink receiving layer is increased. In this case, 5% by weight or less of the solid content of the overcoat layer, preferably 1 / l of the addition amount of the photothermal conversion agent in the ink receiving layer. Addition of about 10 light-to-heat conversion agents may improve sensitivity in some cases. If a light-to-heat conversion agent is added to the overcoat layer beyond this,
Since the light transmittance of the overcoat layer is reduced and sufficient light does not reach the lower layer, the sensitivity may be reduced instead.
When a light-to-heat conversion agent is added to the overcoat layer, the amount of the light-to-heat conversion agent in the ink receiving layer can be reduced according to the amount of the light-to-heat conversion agent.

Inorganic fine particles can be added to the ink receiving layer of the present invention. As inorganic fine particles that can be used,
Colloidal silica and colloidal aluminum up to 10 to 100 nm, and further, inert particles having a particle size larger than these colloids, for example, silica particles, surface-hydrophobized silica particles, alumina particles, titanium dioxide particles, other heavy metal particles, clay And talc. Among the inorganic fine particles, particularly preferred are oxides of at least one element selected from aluminum, silicon, titanium, tin, indium, iron and zirconium.

The colloid particles of colloidal silica or the like are preferably spherical particles having a colloid particle diameter of 5 to 100 nm in the case of silica. 10-50 nm spherical particles,
Colloidal particles in the shape of a pearl necklace connected to a length of 50 to 400 nm can also be used. 100nm x 10nm like colloidal particles of aluminum oxide
Such a feather-like material is also effective. These colloidal dispersions can be purchased from Nissan Chemical Industries, Ltd., or other commercial products. However, "Particle Handbook" (Asakura Shoten)
Fine particles are formed by mechanical pulverization as described in pages 234 to 235, and CVD as described in "Particle Handbook" (Asakura Shoten) pages 226 to 320
It can also be formed by a method such as a vapor deposition method.

As a dispersion medium of these colloidal particles,
In addition to water, organic solvents such as methanol, ethanol, ethylene glycol monomethyl ether, and methyl ethyl ketone are also useful. The addition of these inorganic fine powders to the ink receiving layer has the effect of improving the adhesion to the upper hydrophilic layer and increasing the printing durability in printing. The addition ratio of these fine powders in the ink receiving layer is preferably 0 to 80% by weight of the solid content of the ink receiving layer,
More preferably, it is in the range of 1 to 40% by weight.

Further, a plasticizer may be added to the ink receiving layer of the present invention, if necessary, in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic acid or methacrylic acid And a polymer.

Further, as a color-forming or decoloring-type additive that can be added to the ink receiving layer of the present invention, for example, a thermal acid generator such as a diazo compound or a diphenyliodonium salt and a leuco dye (leucomalachite green, leuco crystal) Violet, a lactone of crystal violet, etc.) and a PH discoloration dye (for example, a dye such as ethyl violet or Victoria Pure Blue BOH) are used in combination. In addition, a combination of an acid coloring dye and an acidic binder as described in EP 897134 is also effective. In this case, the bond in the associated state forming the dye is broken by heating, and a lactone is formed to change from colored to colorless. The additive ratio of these additives is preferably 0 to 1 with respect to the solid content of the ink receiving layer.
0% by weight, more preferably in the range of 0.01 to 5% by weight.

As the solvent for coating the ink receiving layer, alcohols (methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), ethers (tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, tetrahydropyran, etc.), ketones (acetone, methyl ethyl ketone, acetylacetone, etc.), esters ( Methyl acetate, ethyl acetate, ethylene glycol monomethyl ether monoacetate, gamma-butyrolactone, methyl lactate, ethyl lactate, and the like, amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone, and the like) can be used. These solvents are used alone or as a mixture. The concentration of the ink receiving layer component (total solid content including additives) in the coating liquid is preferably 1 to 50% by weight. In addition, a film can be formed not only from the above-mentioned application from an organic solvent but also from an aqueous emulsion. In this case, the concentration is preferably 5% by weight to 50% by weight.

The thickness of the ink receiving layer of the present invention after coating and drying is preferably 0.5 μm to 1.5 μm. If it is too thin, the abrasion resistance is reduced, and the printing durability cannot be secured. If the thickness is too large, it becomes difficult to form an image in the exposure and development process.

The heat-sensitive lithographic printing plate precursor of the present invention forms an image by heat. Specifically, direct image-like recording using a thermal recording head or the like, scanning exposure using an infrared laser, high-intensity flash exposure such as a xenon discharge lamp, or infrared lamp exposure is used. Semiconductors that emit infrared light having a wavelength of 700 to 1200 nm are used. Exposure with a solid-state high-output infrared laser such as a laser or a YAG laser is preferable. The printing plate precursor of the present invention, which has been image-exposed, can be mounted on a printing machine without development after exposure. When the interface between the ink-receiving layer and the hydrophilic layer at the laser-exposed area is peeled off by abrasion and printing is started using ink and dampening water, the ink is applied to the hydrophilic layer exposed by laser exposure. The ink is deposited only on the remaining ink receiving layer without being deposited, and printing proceeds. The overcoat layer is quickly dissolved and removed by contact with the dampening solution, and hardly affects printing. Further, the lithographic printing plate precursor of the present invention can be mounted on a printing press cylinder, exposed by a laser mounted on the printing press, and then developed on a printing press with dampening water and / or ink. It is.

[0076]

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

(Examples 1 to 5, Comparative Examples 1 to 3) [Production of aluminum substrate] 99.5 weight of aluminum
%, Copper 0.01% by weight, iron 0.3% by weight, titanium 0.0%
JIS containing 3% by weight and 0.1% by weight of silicon
 A1050 rolled 0.24mm thick aluminum plate
Of a 400 mesh pamistone (manufactured by Kyoritsu Ceramics)
Weight percent aqueous suspension using a rotating nylon brush
After graining the surface, it was thoroughly washed with water. This is 15
Wt% sodium hydroxide aqueous solution (aluminum 4.5
% Aluminum) and the amount of aluminum dissolved is 10 g /
m^TwoAnd then washed with running water.
Further neutralize with 1% by weight nitric acid aqueous solution, then 0.7% by weight
In a nitric acid aqueous solution (containing 0.5% by weight of aluminum),
Square wave alternating voltage of extreme voltage 10.5V, cathode voltage 9.3V
Waveform voltage (current ratio r = 0.90, Japanese Patent Publication No. 58-5796)
Using the current waveform described in the embodiment of
0C / dm^TwoElectrolytic surface roughening treatment with the amount of electricity at the anode
Was. After washing with water, 35% aqueous solution of 10% by weight sodium hydroxide
Immersed in liquid to dissolve aluminum at 1 g / m^TwoNana
And then washed with water. Next, at 50 ° C,
Dipped and immersed in 30% by weight sulfuric acid aqueous solution
Thereafter, the substrate was washed with water to obtain a substrate [A]. In addition, sulfuric acid at 35 ° C
In a 20% by weight aqueous solution (containing 0.8% by weight of aluminum)
The anodic oxidation treatment was performed using a direct current. Sand
And a current density of 13 A / dm ^TwoAnd electrolysis time
By adjustment, anodic oxide film weight 2.0g / m^TwoForm
A substrate [B] was produced.

[Formation of Hydrophilic Layer] The substrate [A] was used as an aluminum support as it was, and the substrate [B] was heated at 30 ° C.
1 g of film dissolved in aqueous sodium hydroxide solution at pH 13
/ M ² and then washed with water. After the pore widening treatment, a sealing treatment was performed for 12 seconds in a steam chamber saturated at 100 ° C. and 1 atm to prepare an aluminum support. The following hydrophilic layer coating solution [S1] was coated on an aluminum support and dried at 100 ° C. for 1 minute to obtain a lithographic printing plate support (S10) having a hydrophilic layer dry coating amount of 2 g / m ² . . (Hydrophilic layer coating solution [S1]) Polyvinyl alcohol powder 0.5 g Silica fine particles ((B) component) 4 g Methyl lactate 3 g No. 3 sodium silicate ((A) component) Xg Water 92.5-Xg

The silica fine particles used here were silica having a particle size of 0.8 μm, a reagent manufactured by Soekawa Rikagaku Co., Ltd., and No. 3 sodium silicate was manufactured by Nippon Kagaku Kogyo, having a SiO ₂ content of 30% by weight and Na ₂ Those having an O content of 10% by weight were used. The polyvinyl alcohol resin has a polymerization degree of 1750 and a saponification degree of 9
8.6 mol% (Kuraray Co., Ltd. powder) was used.

The content of sodium silicate No. 3 (expressed as Xg) in the aluminum support (substrates [A] and [B]) coated with the hydrophilic layer coating solution [S1] and the hydrophilic layer coating solution [S1] is as follows. The hydrophilic layer coating solutions [S10] to [S14] were adjusted as shown in Table 1. The hydrophilic layer coating solutions [S15] and [S16] were prepared by changing the contents of silica, methyl lactate, and No. 3 sodium silicate in the hydrophilic layer coating solution [S1] as shown in Table 1. A support was prepared using these hydrophilic layer coating solutions. The ratio of the solid content in the hydrophilic layer [(A) / (B)] is shown in the table. As apparent from Table 1, the hydrophilic layer coating liquids [S12] to [S15] are the hydrophilic layers according to the present invention, and the hydrophilic layer coating liquids [S10], [S11], and [S16] are the same as those of the present invention. The hydrophilic layer is out of the range. The solid content ratio was calculated according to the following formula (1), and the results are shown in Table 1 below. Solid content ratio = (SiO ₂ + Na ₂ O in No. 3 sodium silicate) / crystalline SiO ₂ (Formula 1)

[Formation of Ink-Receiving Layer] On each of the hydrophilic layers, an ink-receiving layer coating solution I-1 having the following composition was applied using a bar coater. Thereafter, the ink was dried by heating at 100 ° C. for 1 minute to form an ink receiving layer having a dry coating amount of about 1.2 g / m ² . (Ink receiving layer coating solution I-1) Epicoat 1010 3 g Photothermal conversion agent (IR-24 described in this specification) 0.3 g Methyl ethyl ketone 32.7 g Propylene glycol monomethyl ether 30 g Here, epicoat 1010 has a softening point of 169. C. epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.).

[Overcoat layer] Provided in this manner
Overcoat layer of the following composition on the ink receiving layer
Apply liquid OC-1 and dry at 100 ° C. for 90 seconds.
Dry coating weight 0.25g / m ^TwoHas an overcoat layer of
Heat-sensitive lithographic printing plate precursors [S10] to [S16]
did. (Overcoat layer coating liquid OC-1) 5% aqueous solution of gum arabic 10 g Polyoxyethylene nonylphenyl ether 0.02 g Water 14 g

[Evaluation of Lithographic Printing Plate Precursor] The heat-sensitive lithographic printing plate precursor obtained as described above was exposed with a trend setter (a plate setter equipped with a 40 W 830 nm semiconductor laser) manufactured by Creo Corporation. The exposed original plate was attached to Komori Corporation's Lithrone printing machine without further processing, and the plate etchant EU-3 was used.
Printed using mixed water consisting of (Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol (1/99/10 volume ratio) and Geos G Ink Ink (Dainippon Ink & Chemicals, Inc.). . From the results, an appropriate exposure energy amount (sensitivity) was obtained, and the clear sensitivity, the number of printable sheets (printable number of sheets), and the observation result of the print stain when exposed with this appropriate exposure energy amount are shown in Table 1. . The stainability was evaluated according to the following criteria. Stainability ：: No occurrence of stain is visually observed. Δ: Stain is slightly observed visually. X: The generation of dirt is remarkable.

[0084]

[Table 1]

As is clear from Table 1, the lithographic printing plate precursors of the present invention can be recorded with high sensitivity, and a large number of prints without stain on the non-image area can be obtained. It was confirmed that the film had excellent properties. Example 5 is an embodiment in which an anodic oxide film is not formed, but the film hardness and heat insulating properties are slightly reduced, and therefore, although sensitivity and printing durability are slightly lower than those of Examples 1 to 4, there is a problem in practical use. It can be seen that the evaluation level has no evaluation. On the other hand, (A) the lithographic printing plate of Comparative Example 1 provided with a hydrophilic layer containing no non-crystalline oxide was low in both sensitivity and antifouling property and insufficient in printing durability. Also,
Even in the case of a hydrophilic layer containing (A) an amorphous oxide and (B) metal oxide fine particles, in a comparative example in which the blending ratio of both is outside the range of the present invention, sodium silicate No. 3 (( A)
In Comparative Example 2 having a low (component) ratio, the stain resistance was insufficient and the hydrophilic layer film was cracked, resulting in poor printing durability. Also in Comparative Example 3 in which the ratio of silica ((B) component) was too low, the film properties of the hydrophilic layer were reduced, and the printing durability was insufficient.

(Examples 6 and 7) On the aluminum substrate used in Example 1, the hydrophilic layer coating solution [S
12] was changed to 27 g of 2K potassium silicate (containing 20% by weight of SiO _{2 and} 10% by weight of K ₂ O, manufactured by Nippon Chemical Industry Co., Ltd.), and the amount of water was changed from 82.5 g to 65.5 g. A lithographic printing plate precursor of Example 6 was obtained in the same manner except that the hydrophilic layer coating solution [S17] was used. Further, 10 g of sodium silicate No. 3 in the hydrophilic layer coating solution [S12] used in Example 1 was mixed with lithium silicate 75
(20% by weight of SiO _2, 2.2% by weight of Li ₂ O, Nissan Chemical Industries, Ltd.) Changed to 36 g, and used a hydrophilic layer coating solution [S18] in which the amount of water was changed from 82.5 g to 56.5 g. Except for the above, a lithographic printing plate precursor of Example 7 was obtained in the same manner. These were evaluated in the same manner as in Example 1, and the results are shown in Table 1 above. Table 1 also shows the results of measuring the solid content ratio of the amorphous oxide and the metal oxide fine particles in the hydrophilic layer in the same manner as in Example 1. As is clear from Table 1, even when an alkali metal oxide such as potassium or lithium is used instead of sodium as the water glass, recording is possible with high sensitivity, and stain resistance and printing durability are excellent. It was confirmed that.

(Examples 8 to 14) On the aluminum substrate used in Example 1, a hydrophilic layer coating solution [S4] having the following composition was used. [S41] to [S47] were formed. (Hydrophilic layer coating liquid S4) Polyvinyl alcohol resin powder 0.5 g Metal oxide fine particles (shown in Table 2) 4 g Methyl lactate 3 g No. 3 sodium silicate 30 g Water 62.5 g The polyvinyl alcohol resin used here was polymerized Degree 1750, saponification degree 98.6 mol% (Kuraray Co., Ltd.)
Made). In Table 2, those described as ITO are:
It is a tin-containing indium oxide (a reagent manufactured by Soegawa Rikagaku KK). The results of measuring the solid content ratio of the amorphous oxide and the metal oxide fine particles in the hydrophilic layer in the same manner as in Example 1 are shown in Table 2 below.

[0088]

[Table 2]

An ink receiving layer and an overcoat layer were formed on each of the obtained supports in the same manner as in Example 1 to obtain a lithographic printing plate precursor. The results of evaluating each of the resulting lithographic printing plate precursors in the same manner as in Example 1 are also shown in Table 2 above. As is clear from Table 2, the lithographic printing plate precursor according to the present invention can be recorded with high sensitivity regardless of the type of metal fine particles used, and a large number of prints without stains in the non-image area can be obtained. It was confirmed that the ink had excellent stain resistance and printing durability.

[0090]

According to the lithographic printing plate support of the present invention,
Even when an aluminum plate with high thermal conductivity is used as a substrate, it has high heat insulation, high hydrophilicity, and a durable hydrophilic layer, enabling high-sensitivity recording and printing durability. An excellent lithographic printing plate can be provided. Further, the lithographic printing plate precursor of the present invention using the support does not require a development treatment after exposure, has a high sensitivity and can be recorded, and has an effect of being excellent in stain prevention and printing durability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA01 AA12 AA14 AB03 AC01 AC08 BH03 DA18 DA20 DA36 2H096 AA06 CA03 EA04 EA23 GA45 2H114 AA04 AA14 AA21 AA22 BA01 BA10 DA03 DA04 DA08 DA15 DA34 DA52 DA53 DA55 DA56 DA57 DA60 EA03 EA05 EA08

Claims (2)

[Claims] 1. An aluminum substrate comprising: (A) an amorphous oxide containing silicon and an alkali metal; and (B) aluminum, silicon, titanium, tin, indium, zirconium,
A crystalline oxide of at least one element selected from the group consisting of iron and a solid content weight ratio of both ([A) /
(B)], which has a hydrophilic layer in an amount of 1 to 10. 2. An aluminum substrate comprising: (A) an amorphous oxide containing silicon and an alkali metal; and (B) aluminum, silicon, titanium, tin, indium, zirconium,
A crystalline oxide of at least one element selected from the group consisting of iron and a solid content weight ratio of both ([(A) /
(B)] is a lithographic printing plate precursor comprising an ink receiving layer provided on a lithographic printing plate support having a hydrophilic layer in an amount of 1 to 10; A lithographic printing plate precursor, wherein at least one of the layers contains a light-to-heat conversion agent.